Sema.h source code [llvm_projects/clang/include/clang/Sema/Sema.h]

1	//===--- Sema.h - Semantic Analysis & AST Building --------------- C++ --===//
2	//
3	// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4	// See https://llvm.org/LICENSE.txt for license information.
5	// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6	//
7	//===----------------------------------------------------------------------===//
8	//
9	// This file defines the Sema class, which performs semantic analysis and
10	// builds ASTs.
11	//
12	//===----------------------------------------------------------------------===//
13
14	#ifndef LLVM_CLANG_SEMA_SEMA_H
15	#define LLVM_CLANG_SEMA_SEMA_H
16
17	#include "clang/APINotes/APINotesManager.h"
18	#include "clang/AST/ASTFwd.h"
19	#include "clang/AST/ASTLambda.h"
20	#include "clang/AST/Attr.h"
21	#include "clang/AST/AttrIterator.h"
22	#include "clang/AST/CharUnits.h"
23	#include "clang/AST/DeclBase.h"
24	#include "clang/AST/DeclCXX.h"
25	#include "clang/AST/DeclTemplate.h"
26	#include "clang/AST/DeclarationName.h"
27	#include "clang/AST/Expr.h"
28	#include "clang/AST/ExprCXX.h"
29	#include "clang/AST/ExprConcepts.h"
30	#include "clang/AST/ExternalASTSource.h"
31	#include "clang/AST/NestedNameSpecifier.h"
32	#include "clang/AST/OperationKinds.h"
33	#include "clang/AST/StmtCXX.h"
34	#include "clang/AST/Type.h"
35	#include "clang/AST/TypeLoc.h"
36	#include "clang/Analysis/Analyses/LifetimeSafety/LifetimeAnnotations.h"
37	#include "clang/Basic/AttrSubjectMatchRules.h"
38	#include "clang/Basic/BuiltinTraits.h"
39	#include "clang/Basic/Builtins.h"
40	#include "clang/Basic/CapturedStmt.h"
41	#include "clang/Basic/Cuda.h"
42	#include "clang/Basic/DiagnosticSema.h"
43	#include "clang/Basic/ExceptionSpecificationType.h"
44	#include "clang/Basic/LLVM.h"
45	#include "clang/Basic/Lambda.h"
46	#include "clang/Basic/LangOptions.h"
47	#include "clang/Basic/Module.h"
48	#include "clang/Basic/OpenCLOptions.h"
49	#include "clang/Basic/OperatorKinds.h"
50	#include "clang/Basic/PartialDiagnostic.h"
51	#include "clang/Basic/PragmaKinds.h"
52	#include "clang/Basic/SourceLocation.h"
53	#include "clang/Basic/Specifiers.h"
54	#include "clang/Basic/StackExhaustionHandler.h"
55	#include "clang/Basic/TemplateKinds.h"
56	#include "clang/Basic/TokenKinds.h"
57	#include "clang/Sema/AnalysisBasedWarnings.h"
58	#include "clang/Sema/Attr.h"
59	#include "clang/Sema/CleanupInfo.h"
60	#include "clang/Sema/DeclSpec.h"
61	#include "clang/Sema/ExternalSemaSource.h"
62	#include "clang/Sema/IdentifierResolver.h"
63	#include "clang/Sema/Ownership.h"
64	#include "clang/Sema/ParsedAttr.h"
65	#include "clang/Sema/Redeclaration.h"
66	#include "clang/Sema/Scope.h"
67	#include "clang/Sema/SemaBase.h"
68	#include "clang/Sema/SemaConcept.h"
69	#include "clang/Sema/TypoCorrection.h"
70	#include "clang/Sema/Weak.h"
71	#include "llvm/ADT/APInt.h"
72	#include "llvm/ADT/ArrayRef.h"
73	#include "llvm/ADT/BitmaskEnum.h"
74	#include "llvm/ADT/DenseMap.h"
75	#include "llvm/ADT/DenseSet.h"
76	#include "llvm/ADT/FloatingPointMode.h"
77	#include "llvm/ADT/FoldingSet.h"
78	#include "llvm/ADT/MapVector.h"
79	#include "llvm/ADT/PointerIntPair.h"
80	#include "llvm/ADT/PointerUnion.h"
81	#include "llvm/ADT/STLExtras.h"
82	#include "llvm/ADT/STLForwardCompat.h"
83	#include "llvm/ADT/STLFunctionalExtras.h"
84	#include "llvm/ADT/SetVector.h"
85	#include "llvm/ADT/SmallBitVector.h"
86	#include "llvm/ADT/SmallPtrSet.h"
87	#include "llvm/ADT/SmallSet.h"
88	#include "llvm/ADT/SmallVector.h"
89	#include "llvm/ADT/StringExtras.h"
90	#include "llvm/ADT/StringMap.h"
91	#include "llvm/ADT/TinyPtrVector.h"
92	#include "llvm/Support/Allocator.h"
93	#include "llvm/Support/Compiler.h"
94	#include "llvm/Support/Error.h"
95	#include "llvm/Support/ErrorHandling.h"
96	#include <cassert>
97	#include <climits>
98	#include <cstddef>
99	#include <cstdint>
100	#include <deque>
101	#include <functional>
102	#include <iterator>
103	#include <memory>
104	#include <optional>
105	#include <string>
106	#include <tuple>
107	#include <type_traits>
108	#include <utility>
109	#include <vector>
110
111	namespace llvm {
112	struct InlineAsmIdentifierInfo;
113	} // namespace llvm
114
115	namespace clang {
116	class ADLResult;
117	class APValue;
118	struct ASTConstraintSatisfaction;
119	class ASTConsumer;
120	class ASTContext;
121	class ASTDeclReader;
122	class ASTMutationListener;
123	class ASTReader;
124	class ASTWriter;
125	class CXXBasePath;
126	class CXXBasePaths;
127	class CXXFieldCollector;
128	class CodeCompleteConsumer;
129	enum class ComparisonCategoryType : unsigned char;
130	class ConstraintSatisfaction;
131	class DarwinSDKInfo;
132	class DeclGroupRef;
133	class DeducedTemplateArgument;
134	struct DeductionFailureInfo;
135	class DependentDiagnostic;
136	class Designation;
137	class IdentifierInfo;
138	struct ImplicitAllocationArguments;
139	class ImplicitConversionSequence;
140	typedef MutableArrayRef<ImplicitConversionSequence> ConversionSequenceList;
141	class InitializationKind;
142	class InitializationSequence;
143	class InitializedEntity;
144	enum class LangAS : unsigned int;
145	class LocalInstantiationScope;
146	class LookupResult;
147	class MangleNumberingContext;
148	typedef ArrayRef<IdentifierLoc> ModuleIdPath;
149	class ModuleLoader;
150	class MultiLevelTemplateArgumentList;
151	struct NormalizedConstraint;
152	class ObjCInterfaceDecl;
153	class ObjCMethodDecl;
154	struct OverloadCandidate;
155	enum class OverloadCandidateParamOrder : char;
156	enum OverloadCandidateRewriteKind : unsigned;
157	class OverloadCandidateSet;
158	class Preprocessor;
159	struct APINotesSelectorDiagnosticState;
160	struct ResolvedAllocation;
161	class SemaAMDGPU;
162	class SemaARM;
163	class SemaAVR;
164	class SemaBPF;
165	class SemaCodeCompletion;
166	class SemaCUDA;
167	class SemaDirectX;
168	class SemaHLSL;
169	class SemaHexagon;
170	class SemaLoongArch;
171	class SemaM68k;
172	class SemaMIPS;
173	class SemaMSP430;
174	class SemaNVPTX;
175	class SemaObjC;
176	class SemaOpenACC;
177	class SemaOpenCL;
178	class SemaOpenMP;
179	class SemaPPC;
180	class SemaPseudoObject;
181	class SemaRISCV;
182	class SemaSPIRV;
183	class SemaSYCL;
184	class SemaSwift;
185	class SemaSystemZ;
186	class SemaWasm;
187	class SemaX86;
188	class StandardConversionSequence;
189	class TemplateArgument;
190	class TemplateArgumentLoc;
191	class TemplateInstantiationCallback;
192	class TemplatePartialOrderingContext;
193	class TemplateSpecCandidateSet;
194	class Token;
195	class TypeConstraint;
196	class TypoCorrectionConsumer;
197	class UnresolvedSetImpl;
198	class UnresolvedSetIterator;
199	class VisibleDeclConsumer;
200
201	namespace sema {
202	class BlockScopeInfo;
203	class Capture;
204	class CapturedRegionScopeInfo;
205	class CapturingScopeInfo;
206	class CompoundScopeInfo;
207	class DelayedDiagnostic;
208	class DelayedDiagnosticPool;
209	class FunctionScopeInfo;
210	class LambdaScopeInfo;
211	class SemaPPCallbacks;
212	class TemplateDeductionInfo;
213	} // namespace sema
214
215	// AssignmentAction - This is used by all the assignment diagnostic functions
216	// to represent what is actually causing the operation
217	enum class AssignmentAction {
218	Assigning,
219	Passing,
220	Returning,
221	Converting,
222	Initializing,
223	Sending,
224	Casting,
225	Passing_CFAudited
226	};
227
228	// Inline capacity for type-aware, aligned, and unaligned allocation argument
229	// list candidates.
230	using AllocationArgumentSet = SmallVector<ImplicitAllocationArguments, `3`>;
231
232	namespace threadSafety {
233	class BeforeSet;
234	void threadSafetyCleanup(BeforeSet *Cache);
235	} // namespace threadSafety
236
237	// FIXME: No way to easily map from TemplateTypeParmTypes to
238	// TemplateTypeParmDecls, so we have this horrible PointerUnion.
239	typedef std::pair<llvm::PointerUnion<const TemplateTypeParmType , NamedDecl ,
240	const TemplateSpecializationType *,
241	const SubstBuiltinTemplatePackType *>,
242	SourceLocation>
243	UnexpandedParameterPack;
244
245	/// Describes whether we've seen any nullability information for the given
246	/// file.
247	struct FileNullability {
248	/// The first pointer declarator (of any pointer kind) in the file that does
249	/// not have a corresponding nullability annotation.
250	SourceLocation PointerLoc;
251
252	/// The end location for the first pointer declarator in the file. Used for
253	/// placing fix-its.
254	SourceLocation PointerEndLoc;
255
256	/// Which kind of pointer declarator we saw.
257	uint8_t PointerKind;
258
259	/// Whether we saw any type nullability annotations in the given file.
260	bool SawTypeNullability = false;
261	};
262
263	/// A mapping from file IDs to a record of whether we've seen nullability
264	/// information in that file.
265	class FileNullabilityMap {
266	/// A mapping from file IDs to the nullability information for each file ID.
267	llvm::DenseMap<FileID, FileNullability> Map;
268
269	/// A single-element cache based on the file ID.
270	struct {
271	FileID File;
272	FileNullability Nullability;
273	} Cache;
274
275	public:
276	FileNullability &operator[](FileID file) {
277	// Check the single-element cache.
278	if (file == Cache.File)
279	return Cache.Nullability;
280
281	// It's not in the single-element cache; flush the cache if we have one.
282	if (!Cache.File.isInvalid()) {
283	Map [Cache.File] = Cache.Nullability;
284	}
285
286	// Pull this entry into the cache.
287	Cache.File = file;
288	Cache.Nullability = Map [file];
289	return Cache.Nullability;
290	}
291	};
292
293	/// Tracks expected type during expression parsing, for use in code completion.
294	/// The type is tied to a particular token, all functions that update or consume
295	/// the type take a start location of the token they are looking at as a
296	/// parameter. This avoids updating the type on hot paths in the parser.
297	class PreferredTypeBuilder {
298	public:
299	PreferredTypeBuilder(ASTContext Ctx, bool* Enabled)
300	: Ctx(Ctx), Enabled(Enabled) {}
301
302	void enterCondition(Sema &S, SourceLocation Tok);
303	void enterReturn(Sema &S, SourceLocation Tok);
304	void enterVariableInit(SourceLocation Tok, Decl *D);
305	/// Handles e.g. BaseType{ .D = Tok...
306	void enterDesignatedInitializer(SourceLocation Tok, QualType BaseType,
307	const Designation &D);
308	/// Computing a type for the function argument may require running
309	/// overloading, so we postpone its computation until it is actually needed.
310	///
311	/// Clients should be very careful when using this function, as it stores a
312	/// function_ref, clients should make sure all calls to get() with the same
313	/// location happen while function_ref is alive.
314	///
315	/// The callback should also emit signature help as a side-effect, but only
316	/// if the completion point has been reached.
317	void enterFunctionArgument(SourceLocation Tok,
318	llvm::function_ref<QualType()> ComputeType);
319
320	void enterParenExpr(SourceLocation Tok, SourceLocation LParLoc);
321	void enterUnary(Sema &S, SourceLocation Tok, tok::TokenKind OpKind,
322	SourceLocation OpLoc);
323	void enterBinary(Sema &S, SourceLocation Tok, Expr *LHS, tok::TokenKind Op);
324	void enterMemAccess(Sema &S, SourceLocation Tok, Expr *Base);
325	void enterSubscript(Sema &S, SourceLocation Tok, Expr *LHS);
326	/// Handles all type casts, including C-style cast, C++ casts, etc.
327	void enterTypeCast(SourceLocation Tok, QualType CastType);
328
329	/// Get the expected type associated with this location, if any.
330	///
331	/// If the location is a function argument, determining the expected type
332	/// involves considering all function overloads and the arguments so far.
333	/// In this case, signature help for these function overloads will be reported
334	/// as a side-effect (only if the completion point has been reached).
335	QualType get(SourceLocation Tok) const {
336	if (!Enabled \|\| Tok != ExpectedLoc)
337	return QualType ();
338	if (!Type.isNull())
339	return Type;
340	if (ComputeType)
341	return ComputeType ();
342	return QualType ();
343	}
344
345	private:
346	ASTContext *Ctx;
347	bool Enabled;
348	/// Start position of a token for which we store expected type.
349	SourceLocation ExpectedLoc;
350	/// Expected type for a token starting at ExpectedLoc.
351	QualType Type;
352	/// A function to compute expected type at ExpectedLoc. It is only considered
353	/// if Type is null.
354	llvm::function_ref<QualType()> ComputeType;
355	};
356
357	struct SkipBodyInfo {
358	SkipBodyInfo() = default;
359	bool ShouldSkip = false;
360	bool CheckSameAsPrevious = false;
361	NamedDecl Previous = nullptr*;
362	NamedDecl New = nullptr*;
363	};
364
365	/// Describes the result of template argument deduction.
366	///
367	/// The TemplateDeductionResult enumeration describes the result of
368	/// template argument deduction, as returned from
369	/// DeduceTemplateArguments(). The separate TemplateDeductionInfo
370	/// structure provides additional information about the results of
371	/// template argument deduction, e.g., the deduced template argument
372	/// list (if successful) or the specific template parameters or
373	/// deduced arguments that were involved in the failure.
374	enum class TemplateDeductionResult {
375	/// Template argument deduction was successful.
376	Success = `0`,
377	/// The declaration was invalid; do nothing.
378	Invalid,
379	/// Template argument deduction exceeded the maximum template
380	/// instantiation depth (which has already been diagnosed).
381	InstantiationDepth,
382	/// Template argument deduction did not deduce a value
383	/// for every template parameter.
384	Incomplete,
385	/// Template argument deduction did not deduce a value for every
386	/// expansion of an expanded template parameter pack.
387	IncompletePack,
388	/// Template argument deduction produced inconsistent
389	/// deduced values for the given template parameter.
390	Inconsistent,
391	/// Template argument deduction failed due to inconsistent
392	/// cv-qualifiers on a template parameter type that would
393	/// otherwise be deduced, e.g., we tried to deduce T in "const T"
394	/// but were given a non-const "X".
395	Underqualified,
396	/// Substitution of the deduced template argument values
397	/// resulted in an error.
398	SubstitutionFailure,
399	/// After substituting deduced template arguments, a dependent
400	/// parameter type did not match the corresponding argument.
401	DeducedMismatch,
402	/// After substituting deduced template arguments, an element of
403	/// a dependent parameter type did not match the corresponding element
404	/// of the corresponding argument (when deducing from an initializer list).
405	DeducedMismatchNested,
406	/// A non-depnedent component of the parameter did not match the
407	/// corresponding component of the argument.
408	NonDeducedMismatch,
409	/// When performing template argument deduction for a function
410	/// template, there were too many call arguments.
411	TooManyArguments,
412	/// When performing template argument deduction for a function
413	/// template, there were too few call arguments.
414	TooFewArguments,
415	/// The explicitly-specified template arguments were not valid
416	/// template arguments for the given template.
417	InvalidExplicitArguments,
418	/// Checking non-dependent argument conversions failed.
419	NonDependentConversionFailure,
420	/// The deduced arguments did not satisfy the constraints associated
421	/// with the template.
422	ConstraintsNotSatisfied,
423	/// Deduction failed; that's all we know.
424	MiscellaneousDeductionFailure,
425	/// CUDA Target attributes do not match.
426	CUDATargetMismatch,
427	/// Some error which was already diagnosed.
428	AlreadyDiagnosed
429	};
430
431	/// The kind of conversion being performed.
432	enum class CheckedConversionKind {
433	/// An implicit conversion.
434	Implicit,
435	/// A C-style cast.
436	CStyleCast,
437	/// A functional-style cast.
438	FunctionalCast,
439	/// A cast other than a C-style cast.
440	OtherCast,
441	/// A conversion for an operand of a builtin overloaded operator.
442	ForBuiltinOverloadedOp
443	};
444
445	enum class TagUseKind {
446	Reference, // Reference to a tag: 'struct foo X;'*
447	Declaration, // Fwd decl of a tag: 'struct foo;'
448	Definition, // Definition of a tag: 'struct foo { int X; } Y;'
449	Friend // Friend declaration: 'friend struct foo;'
450	};
451
452	/// Used with attributes/effects with a boolean condition, e.g. `nonblocking`.
453	enum class FunctionEffectMode : uint8_t {
454	None, // effect is not present.
455	False, // effect(false).
456	True, // effect(true).
457	Dependent // effect(expr) where expr is dependent.
458	};
459
460	/// pragma clang section kind
461	enum class PragmaClangSectionKind {
462	Invalid = `0`,
463	BSS = `1`,
464	Data = `2`,
465	Rodata = `3`,
466	Text = `4`,
467	Relro = `5`
468	};
469
470	enum class PragmaClangSectionAction { Set = `0`, Clear = `1` };
471
472	enum class PragmaOptionsAlignKind {
473	Native, // #pragma options align=native
474	Natural, // #pragma options align=natural
475	Packed, // #pragma options align=packed
476	Power, // #pragma options align=power
477	Mac68k, // #pragma options align=mac68k
478	Reset // #pragma options align=reset
479	};
480
481	enum class TUFragmentKind {
482	/// The global module fragment, between 'module;' and a module-declaration.
483	Global,
484	/// A normal translation unit fragment. For a non-module unit, this is the
485	/// entire translation unit. Otherwise, it runs from the module-declaration
486	/// to the private-module-fragment (if any) or the end of the TU (if not).
487	Normal,
488	/// The private module fragment, between 'module :private;' and the end of
489	/// the translation unit.
490	Private
491	};
492
493	enum class FormatStringType {
494	Scanf,
495	Printf,
496	NSString,
497	Strftime,
498	Strfmon,
499	Kprintf,
500	FreeBSDKPrintf,
501	OSTrace,
502	OSLog,
503	Unknown
504	};
505
506	// Used for emitting the right warning by DefaultVariadicArgumentPromotion
507	enum class VariadicCallType {
508	Function,
509	Block,
510	Method,
511	Constructor,
512	DoesNotApply
513	};
514
515	enum class BuiltinCountedByRefKind {
516	Assignment,
517	Initializer,
518	FunctionArg,
519	ReturnArg,
520	ArraySubscript,
521	BinaryExpr,
522	};
523
524	// Contexts where using non-trivial C union types can be disallowed. This is
525	// passed to err_non_trivial_c_union_in_invalid_context.
526	enum class NonTrivialCUnionContext {
527	// Function parameter.
528	FunctionParam,
529	// Function return.
530	FunctionReturn,
531	// Default-initialized object.
532	DefaultInitializedObject,
533	// Variable with automatic storage duration.
534	AutoVar,
535	// Initializer expression that might copy from another object.
536	CopyInit,
537	// Assignment.
538	Assignment,
539	// Compound literal.
540	CompoundLiteral,
541	// Block capture.
542	BlockCapture,
543	// lvalue-to-rvalue conversion of volatile type.
544	LValueToRValueVolatile,
545	};
546
547	/// Describes the result of the name lookup and resolution performed
548	/// by \c Sema::ClassifyName().
549	enum class NameClassificationKind {
550	/// This name is not a type or template in this context, but might be
551	/// something else.
552	Unknown,
553	/// Classification failed; an error has been produced.
554	Error,
555	/// The name has been typo-corrected to a keyword.
556	Keyword,
557	/// The name was classified as a type.
558	Type,
559	/// The name was classified as a specific non-type, non-template
560	/// declaration. ActOnNameClassifiedAsNonType should be called to
561	/// convert the declaration to an expression.
562	NonType,
563	/// The name was classified as an ADL-only function name.
564	/// ActOnNameClassifiedAsUndeclaredNonType should be called to convert the
565	/// result to an expression.
566	UndeclaredNonType,
567	/// The name denotes a member of a dependent type that could not be
568	/// resolved. ActOnNameClassifiedAsDependentNonType should be called to
569	/// convert the result to an expression.
570	DependentNonType,
571	/// The name was classified as an overload set, and an expression
572	/// representing that overload set has been formed.
573	/// ActOnNameClassifiedAsOverloadSet should be called to form a suitable
574	/// expression referencing the overload set.
575	OverloadSet,
576	/// The name was classified as a template whose specializations are types.
577	TypeTemplate,
578	/// The name was classified as a variable template name.
579	VarTemplate,
580	/// The name was classified as a function template name.
581	FunctionTemplate,
582	/// The name was classified as an ADL-only function template name.
583	UndeclaredTemplate,
584	/// The name was classified as a concept name.
585	Concept,
586	};
587
588	enum class PointerAuthDiscArgKind {
589	// Address discrimination argument of __ptrauth.
590	Addr,
591
592	// Extra discriminator argument of __ptrauth.
593	Extra,
594	};
595
596	/// Common ways to introduce type names without a tag for use in diagnostics.
597	/// Keep in sync with err_tag_reference_non_tag.
598	enum class NonTagKind {
599	NonStruct,
600	NonClass,
601	NonUnion,
602	NonEnum,
603	Typedef,
604	TypeAlias,
605	Template,
606	TypeAliasTemplate,
607	TemplateTemplateArgument,
608	};
609
610	enum class OffsetOfKind {
611	// Not parsing a type within __builtin_offsetof.
612	Outside,
613	// Parsing a type within __builtin_offsetof.
614	Builtin,
615	// Parsing a type within macro "offsetof", defined in __buitin_offsetof
616	// To improve our diagnostic message.
617	Macro,
618	};
619
620	/// Describes the kind of merge to perform for availability
621	/// attributes (including "deprecated", "unavailable", and "availability").
622	enum class AvailabilityMergeKind {
623	/// Don't merge availability attributes at all.
624	None,
625	/// Merge availability attributes for a redeclaration, which requires
626	/// an exact match.
627	Redeclaration,
628	/// Merge availability attributes for an override, which requires
629	/// an exact match or a weakening of constraints.
630	Override,
631	/// Merge availability attributes for an implementation of
632	/// a protocol requirement.
633	ProtocolImplementation,
634	/// Merge availability attributes for an implementation of
635	/// an optional protocol requirement.
636	OptionalProtocolImplementation
637	};
638
639	enum class TrivialABIHandling {
640	/// The triviality of a method unaffected by "trivial_abi".
641	IgnoreTrivialABI,
642
643	/// The triviality of a method affected by "trivial_abi".
644	ConsiderTrivialABI
645	};
646
647	enum class TryCaptureKind { Implicit, ExplicitByVal, ExplicitByRef };
648
649	enum class AllowFoldKind {
650	No,
651	Allow,
652	};
653
654	/// Context in which we're performing a usual arithmetic conversion.
655	enum class ArithConvKind {
656	/// An arithmetic operation.
657	Arithmetic,
658	/// A bitwise operation.
659	BitwiseOp,
660	/// A comparison.
661	Comparison,
662	/// A conditional (?:) operator.
663	Conditional,
664	/// A compound assignment expression.
665	CompAssign,
666	};
667
668	// Used for determining in which context a type is allowed to be passed to a
669	// vararg function.
670	enum class VarArgKind {
671	Valid,
672	ValidInCXX11,
673	Undefined,
674	MSVCUndefined,
675	Invalid
676	};
677
678	/// AssignConvertType - All of the 'assignment' semantic checks return this
679	/// enum to indicate whether the assignment was allowed. These checks are
680	/// done for simple assignments, as well as initialization, return from
681	/// function, argument passing, etc. The query is phrased in terms of a
682	/// source and destination type.
683	enum class AssignConvertType {
684	/// Compatible - the types are compatible according to the standard.
685	Compatible,
686
687	/// CompatibleVoidPtrToNonVoidPtr - The types are compatible in C because
688	/// a void can implicitly convert to another pointer type, which we*
689	/// differentiate for better diagnostic behavior.
690	CompatibleVoidPtrToNonVoidPtr,
691
692	/// PointerToInt - The assignment converts a pointer to an int, which we
693	/// accept as an extension.
694	PointerToInt,
695
696	/// IntToPointer - The assignment converts an int to a pointer, which we
697	/// accept as an extension.
698	IntToPointer,
699
700	/// FunctionVoidPointer - The assignment is between a function pointer and
701	/// void, which the standard doesn't allow, but we accept as an extension.*
702	FunctionVoidPointer,
703
704	/// IncompatiblePointer - The assignment is between two pointers types that
705	/// are not compatible, but we accept them as an extension.
706	IncompatiblePointer,
707
708	/// IncompatibleFunctionPointer - The assignment is between two function
709	/// pointers types that are not compatible, but we accept them as an
710	/// extension.
711	IncompatibleFunctionPointer,
712
713	/// IncompatibleFunctionPointerStrict - The assignment is between two
714	/// function pointer types that are not identical, but are compatible,
715	/// unless compiled with -fsanitize=cfi, in which case the type mismatch
716	/// may trip an indirect call runtime check.
717	IncompatibleFunctionPointerStrict,
718
719	/// IncompatiblePointerSign - The assignment is between two pointers types
720	/// which point to integers which have a different sign, but are otherwise
721	/// identical. This is a subset of the above, but broken out because it's by
722	/// far the most common case of incompatible pointers.
723	IncompatiblePointerSign,
724
725	/// CompatiblePointerDiscardsQualifiers - The assignment discards
726	/// c/v/r qualifiers, which we accept as an extension.
727	CompatiblePointerDiscardsQualifiers,
728
729	/// IncompatiblePointerDiscardsQualifiers - The assignment
730	/// discards qualifiers that we don't permit to be discarded,
731	/// like address spaces.
732	IncompatiblePointerDiscardsQualifiers,
733
734	/// IncompatiblePointerDiscardsOverflowBehavior - The assignment
735	/// discards overflow behavior annotations between otherwise compatible
736	/// pointer types.
737	IncompatiblePointerDiscardsOverflowBehavior,
738
739	/// IncompatibleNestedPointerAddressSpaceMismatch - The assignment
740	/// changes address spaces in nested pointer types which is not allowed.
741	/// For instance, converting __private int * to __generic int ** is*
742	/// illegal even though __private could be converted to __generic.
743	IncompatibleNestedPointerAddressSpaceMismatch,
744
745	/// IncompatibleNestedPointerQualifiers - The assignment is between two
746	/// nested pointer types, and the qualifiers other than the first two
747	/// levels differ e.g. char * -> const char *, but we accept them as an
748	/// extension.
749	IncompatibleNestedPointerQualifiers,
750
751	/// IncompatibleVectors - The assignment is between two vector types that
752	/// have the same size, which we accept as an extension.
753	IncompatibleVectors,
754
755	/// IntToBlockPointer - The assignment converts an int to a block
756	/// pointer. We disallow this.
757	IntToBlockPointer,
758
759	/// IncompatibleBlockPointer - The assignment is between two block
760	/// pointers types that are not compatible.
761	IncompatibleBlockPointer,
762
763	/// IncompatibleObjCQualifiedId - The assignment is between a qualified
764	/// id type and something else (that is incompatible with it). For example,
765	/// "id <XXX>" = "Foo ", where "Foo " doesn't implement the XXX protocol.
766	IncompatibleObjCQualifiedId,
767
768	/// IncompatibleObjCWeakRef - Assigning a weak-unavailable object to an
769	/// object with __weak qualifier.
770	IncompatibleObjCWeakRef,
771
772	/// IncompatibleOBTKinds - Assigning between incompatible OverflowBehaviorType
773	/// kinds, e.g., from __ob_trap to __ob_wrap or vice versa.
774	IncompatibleOBTKinds,
775
776	/// CompatibleOBTDiscards - Assignment discards overflow behavior
777	CompatibleOBTDiscards,
778
779	/// Incompatible - We reject this conversion outright, it is invalid to
780	/// represent it in the AST.
781	Incompatible
782	};
783
784	/// The scope in which to find allocation functions.
785	enum class AllocationFunctionScope {
786	/// Only look for allocation functions in the global scope.
787	Global,
788	/// Only look for allocation functions in the scope of the
789	/// allocated class.
790	Class,
791	/// Look for allocation functions in both the global scope
792	/// and in the scope of the allocated class.
793	Both
794	};
795
796	/// Describes the result of an "if-exists" condition check.
797	enum class IfExistsResult {
798	/// The symbol exists.
799	Exists,
800
801	/// The symbol does not exist.
802	DoesNotExist,
803
804	/// The name is a dependent name, so the results will differ
805	/// from one instantiation to the next.
806	Dependent,
807
808	/// An error occurred.
809	Error
810	};
811
812	enum class CorrectTypoKind {
813	NonError, // CorrectTypo used in a non error recovery situation.
814	ErrorRecovery // CorrectTypo used in normal error recovery.
815	};
816
817	enum class OverloadKind {
818	/// This is a legitimate overload: the existing declarations are
819	/// functions or function templates with different signatures.
820	Overload,
821
822	/// This is not an overload because the signature exactly matches
823	/// an existing declaration.
824	Match,
825
826	/// This is not an overload because the lookup results contain a
827	/// non-function.
828	NonFunction
829	};
830
831	/// Contexts in which a converted constant expression is required.
832	enum class CCEKind {
833	CaseValue, ///< Expression in a case label.
834	Enumerator, ///< Enumerator value with fixed underlying type.
835	TemplateArg, ///< Value of a non-type template parameter.
836	TempArgStrict, ///< As above, but applies strict template checking
837	///< rules.
838	ArrayBound, ///< Array bound in array declarator or new-expression.
839	ExplicitBool, ///< Condition in an explicit(bool) specifier.
840	Noexcept, ///< Condition in a noexcept(bool) specifier.
841	StaticAssertMessageSize, ///< Call to size() in a static assert
842	///< message.
843	StaticAssertMessageData, ///< Call to data() in a static assert
844	///< message.
845	PackIndex ///< Index of a pack indexing expression or specifier.
846	};
847
848	/// Enums for the diagnostics of target, target_version and target_clones.
849	namespace DiagAttrParams {
850	enum DiagType { Unsupported, Duplicate, Unknown };
851	enum Specifier { None, CPU, Tune };
852	enum AttrName { Target, TargetClones, TargetVersion };
853	} // end namespace DiagAttrParams
854
855	void inferNoReturnAttr(Sema &S, Decl *D);
856
857	#ifdef __GNUC__
858	#pragma GCC diagnostic push
859	#pragma GCC diagnostic ignored "-Wattributes"
860	#endif
861	/// Sema - This implements semantic analysis and AST building for C.
862	/// \nosubgrouping
863	class Sema final : public SemaBase {
864	#ifdef __GNUC__
865	#pragma GCC diagnostic pop
866	#endif
867	// Table of Contents
868	// -----------------
869	// 1. Semantic Analysis (Sema.cpp)
870	// 2. API Notes (SemaAPINotes.cpp)
871	// 3. C++ Access Control (SemaAccess.cpp)
872	// 4. Attributes (SemaAttr.cpp)
873	// 5. Availability Attribute Handling (SemaAvailability.cpp)
874	// 6. Bounds Safety (SemaBoundsSafety.cpp)
875	// 7. Casts (SemaCast.cpp)
876	// 8. Extra Semantic Checking (SemaChecking.cpp)
877	// 9. C++ Coroutines (SemaCoroutine.cpp)
878	// 10. C++ Scope Specifiers (SemaCXXScopeSpec.cpp)
879	// 11. Declarations (SemaDecl.cpp)
880	// 12. Declaration Attribute Handling (SemaDeclAttr.cpp)
881	// 13. C++ Declarations (SemaDeclCXX.cpp)
882	// 14. C++ Exception Specifications (SemaExceptionSpec.cpp)
883	// 15. Expressions (SemaExpr.cpp)
884	// 16. C++ Expressions (SemaExprCXX.cpp)
885	// 17. Member Access Expressions (SemaExprMember.cpp)
886	// 18. Initializers (SemaInit.cpp)
887	// 19. C++ Lambda Expressions (SemaLambda.cpp)
888	// 20. Name Lookup (SemaLookup.cpp)
889	// 21. Modules (SemaModule.cpp)
890	// 22. C++ Overloading (SemaOverload.cpp)
891	// 23. Statements (SemaStmt.cpp)
892	// 24. `inline asm` Statement (SemaStmtAsm.cpp)
893	// 25. Statement Attribute Handling (SemaStmtAttr.cpp)
894	// 26. C++ Templates (SemaTemplate.cpp)
895	// 27. C++ Template Argument Deduction (SemaTemplateDeduction.cpp)
896	// 28. C++ Template Deduction Guide (SemaTemplateDeductionGuide.cpp)
897	// 29. C++ Template Instantiation (SemaTemplateInstantiate.cpp)
898	// 30. C++ Template Declaration Instantiation
899	// (SemaTemplateInstantiateDecl.cpp)
900	// 31. C++ Variadic Templates (SemaTemplateVariadic.cpp)
901	// 32. Constraints and Concepts (SemaConcept.cpp)
902	// 33. Types (SemaType.cpp)
903	// 34. FixIt Helpers (SemaFixItUtils.cpp)
904	// 35. Function Effects (SemaFunctionEffects.cpp)
905	// 36. C++ Expansion Statements (SemaExpand.cpp)
906
907	/// \name Semantic Analysis
908	/// Implementations are in Sema.cpp
909	///@{
910
911	public:
912	Sema(Preprocessor &pp, ASTContext &ctxt, ASTConsumer &consumer,
913	TranslationUnitKind TUKind = TU_Complete,
914	CodeCompleteConsumer CompletionConsumer = nullptr*);
915	~Sema();
916
917	/// Perform initialization that occurs after the parser has been
918	/// initialized but before it parses anything.
919	void Initialize();
920
921	/// This virtual key function only exists to limit the emission of debug info
922	/// describing the Sema class. GCC and Clang only emit debug info for a class
923	/// with a vtable when the vtable is emitted. Sema is final and not
924	/// polymorphic, but the debug info size savings are so significant that it is
925	/// worth adding a vtable just to take advantage of this optimization.
926	LLVM_DECLARE_VIRTUAL_ANCHOR_FUNCTION();
927
928	const LangOptions &getLangOpts() const { return LangOpts; }
929	OpenCLOptions &getOpenCLOptions() { return OpenCLFeatures; }
930	FPOptions &getCurFPFeatures() { return CurFPFeatures; }
931
932	DiagnosticsEngine &getDiagnostics() const { return Diags; }
933	SourceManager &getSourceManager() const { return SourceMgr; }
934	Preprocessor &getPreprocessor() const { return PP; }
935	ASTContext &getASTContext() const { return Context; }
936	ASTConsumer &getASTConsumer() const { return Consumer; }
937	ASTMutationListener getASTMutationListener() const*;
938	ExternalSemaSource getExternalSource() const* { return ExternalSource.get(); }
939
940	DarwinSDKInfo *getDarwinSDKInfoForAvailabilityChecking(SourceLocation Loc,
941	StringRef Platform);
942	DarwinSDKInfo *getDarwinSDKInfoForAvailabilityChecking();
943
944	/// Registers an external source. If an external source already exists,
945	/// creates a multiplex external source and appends to it.
946	///
947	///\param[in] E - A non-null external sema source.
948	///
949	void addExternalSource(IntrusiveRefCntPtr<ExternalSemaSource> E);
950
951	/// Print out statistics about the semantic analysis.
952	void PrintStats() const;
953
954	/// Run some code with "sufficient" stack space. (Currently, at least 256K is
955	/// guaranteed). Produces a warning if we're low on stack space and allocates
956	/// more in that case. Use this in code that may recurse deeply (for example,
957	/// in template instantiation) to avoid stack overflow.
958	void runWithSufficientStackSpace(SourceLocation Loc,
959	llvm::function_ref<void()> Fn);
960
961	/// Returns default addr space for method qualifiers.
962	LangAS getDefaultCXXMethodAddrSpace() const;
963
964	/// Load weak undeclared identifiers from the external source.
965	void LoadExternalWeakUndeclaredIdentifiers();
966
967	/// Load #pragma redefine_extname'd undeclared identifiers from the external
968	/// source.
969	void LoadExternalExtnameUndeclaredIdentifiers();
970
971	/// Determine if VD, which must be a variable or function, is an external
972	/// symbol that nonetheless can't be referenced from outside this translation
973	/// unit because its type has no linkage and it's not extern "C".
974	bool isExternalWithNoLinkageType(const ValueDecl VD) const*;
975
976	/// Determines whether the given source location is in the main file
977	/// and we're in a context where we should warn about unused entities.
978	bool isMainFileLoc(SourceLocation Loc) const;
979
980	/// Obtain a sorted list of functions that are undefined but ODR-used.
981	void getUndefinedButUsed(
982	SmallVectorImpl<std::pair<NamedDecl *, SourceLocation>> &Undefined);
983
984	typedef std::pair<SourceLocation, bool> DeleteExprLoc;
985	typedef llvm::SmallVector<DeleteExprLoc, `4`> DeleteLocs;
986	/// Retrieves list of suspicious delete-expressions that will be checked at
987	/// the end of translation unit.
988	const llvm::MapVector<FieldDecl *, DeleteLocs> &
989	getMismatchingDeleteExpressions() const;
990
991	/// Cause the built diagnostic to be emitted on the DiagosticsEngine.
992	/// This is closely coupled to the SemaDiagnosticBuilder class and
993	/// should not be used elsewhere.
994	void EmitDiagnostic(unsigned DiagID, const DiagnosticBuilder &DB);
995
996	void addImplicitTypedef(StringRef Name, QualType T);
997
998	/// Whether uncompilable error has occurred. This includes error happens
999	/// in deferred diagnostics.
1000	bool hasUncompilableErrorOccurred() const;
1001
1002	/// Looks through the macro-expansion chain for the given
1003	/// location, looking for a macro expansion with the given name.
1004	/// If one is found, returns true and sets the location to that
1005	/// expansion loc.
1006	bool findMacroSpelling(SourceLocation &loc, StringRef name);
1007
1008	/// Calls \c Lexer::getLocForEndOfToken()
1009	SourceLocation getLocForEndOfToken(SourceLocation Loc, unsigned Offset = `0`);
1010
1011	/// Calls \c Lexer::findNextToken() to find the next token, and if the
1012	/// locations of both ends of the token can be resolved it return that
1013	/// range; Otherwise it returns an invalid SourceRange.
1014	SourceRange getRangeForNextToken(
1015	SourceLocation Loc, bool IncludeMacros, bool IncludeComments,
1016	std::optional<tok::TokenKind> ExpectedToken = std::nullopt);
1017
1018	/// Retrieve the module loader associated with the preprocessor.
1019	ModuleLoader &getModuleLoader() const;
1020
1021	/// Invent a new identifier for parameters of abbreviated templates.
1022	IdentifierInfo *
1023	InventAbbreviatedTemplateParameterTypeName(const IdentifierInfo *ParamName,
1024	unsigned Index);
1025
1026	void emitAndClearUnusedLocalTypedefWarnings();
1027
1028	// Emit all deferred diagnostics.
1029	void emitDeferredDiags();
1030
1031	/// This is called before the very first declaration in the translation unit
1032	/// is parsed. Note that the ASTContext may have already injected some
1033	/// declarations.
1034	void ActOnStartOfTranslationUnit();
1035	/// ActOnEndOfTranslationUnit - This is called at the very end of the
1036	/// translation unit when EOF is reached and all but the top-level scope is
1037	/// popped.
1038	void ActOnEndOfTranslationUnit();
1039	void ActOnEndOfTranslationUnitFragment(TUFragmentKind Kind);
1040
1041	/// Determines the active Scope associated with the given declaration
1042	/// context.
1043	///
1044	/// This routine maps a declaration context to the active Scope object that
1045	/// represents that declaration context in the parser. It is typically used
1046	/// from "scope-less" code (e.g., template instantiation, lazy creation of
1047	/// declarations) that injects a name for name-lookup purposes and, therefore,
1048	/// must update the Scope.
1049	///
1050	/// \returns The scope corresponding to the given declaraion context, or NULL
1051	/// if no such scope is open.
1052	Scope getScopeForContext(DeclContext Ctx);
1053
1054	void PushFunctionScope();
1055	void PushBlockScope(Scope BlockScope, BlockDecl Block);
1056	sema::LambdaScopeInfo *PushLambdaScope();
1057
1058	/// This is used to inform Sema what the current TemplateParameterDepth
1059	/// is during Parsing. Currently it is used to pass on the depth
1060	/// when parsing generic lambda 'auto' parameters.
1061	void RecordParsingTemplateParameterDepth(unsigned Depth);
1062
1063	void PushCapturedRegionScope(Scope RegionScope, CapturedDecl CD,
1064	RecordDecl *RD, CapturedRegionKind K,
1065	unsigned OpenMPCaptureLevel = `0`);
1066
1067	/// Custom deleter to allow FunctionScopeInfos to be kept alive for a short
1068	/// time after they've been popped.
1069	class PoppedFunctionScopeDeleter {
1070	Sema *Self;
1071
1072	public:
1073	explicit PoppedFunctionScopeDeleter(Sema *Self) : Self(Self) {}
1074	void operator()(sema::FunctionScopeInfo Scope) const*;
1075	};
1076
1077	using PoppedFunctionScopePtr =
1078	std::unique_ptr<sema::FunctionScopeInfo, PoppedFunctionScopeDeleter>;
1079
1080	/// Pop a function (or block or lambda or captured region) scope from the
1081	/// stack.
1082	///
1083	/// \param WP The warning policy to use for CFG-based warnings, or null if
1084	/// such warnings should not be produced.
1085	/// \param D The declaration corresponding to this function scope, if
1086	/// producing CFG-based warnings.
1087	/// \param BlockType The type of the block expression, if D is a BlockDecl.
1088	PoppedFunctionScopePtr
1089	PopFunctionScopeInfo(const sema::AnalysisBasedWarnings::Policy WP = nullptr*,
1090	Decl D = nullptr*, QualType BlockType = QualType ());
1091
1092	sema::FunctionScopeInfo getEnclosingFunction() const*;
1093
1094	void setFunctionHasBranchIntoScope();
1095	void setFunctionHasBranchProtectedScope();
1096	void setFunctionHasIndirectGoto();
1097	void setFunctionHasMustTail();
1098
1099	void PushCompoundScope(bool IsStmtExpr);
1100	void PopCompoundScope();
1101
1102	/// Determine whether any errors occurred within this function/method/
1103	/// block.
1104	bool hasAnyUnrecoverableErrorsInThisFunction() const;
1105
1106	/// Retrieve the current block, if any.
1107	sema::BlockScopeInfo *getCurBlock();
1108
1109	/// Get the innermost lambda or block enclosing the current location, if any.
1110	/// This looks through intervening non-lambda, non-block scopes such as local
1111	/// functions.
1112	sema::CapturingScopeInfo getEnclosingLambdaOrBlock() const*;
1113
1114	/// Retrieve the current lambda scope info, if any.
1115	/// \param IgnoreNonLambdaCapturingScope true if should find the top-most
1116	/// lambda scope info ignoring all inner capturing scopes that are not
1117	/// lambda scopes.
1118	sema::LambdaScopeInfo *
1119	getCurLambda(bool IgnoreNonLambdaCapturingScope = false);
1120
1121	/// Retrieve the current generic lambda info, if any.
1122	sema::LambdaScopeInfo *getCurGenericLambda();
1123
1124	/// Retrieve the current captured region, if any.
1125	sema::CapturedRegionScopeInfo *getCurCapturedRegion();
1126
1127	void ActOnComment(SourceRange Comment);
1128
1129	/// Retrieve the parser's current scope.
1130	///
1131	/// This routine must only be used when it is certain that semantic analysis
1132	/// and the parser are in precisely the same context, which is not the case
1133	/// when, e.g., we are performing any kind of template instantiation.
1134	/// Therefore, the only safe places to use this scope are in the parser
1135	/// itself and in routines directly invoked from the parser and never* from*
1136	/// template substitution or instantiation.
1137	Scope getCurScope() const* { return CurScope; }
1138
1139	IdentifierInfo getSuperIdentifier() const*;
1140
1141	DeclContext getCurLexicalContext() const* {
1142	return OriginalLexicalContext ? OriginalLexicalContext : CurContext;
1143	}
1144
1145	SemaDiagnosticBuilder targetDiag(SourceLocation Loc, unsigned DiagID,
1146	const FunctionDecl FD = nullptr*);
1147	SemaDiagnosticBuilder targetDiag(SourceLocation Loc,
1148	const PartialDiagnostic &PD,
1149	const FunctionDecl FD = nullptr*) {
1150	return targetDiag(Loc, DiagID: PD.getDiagID(), FD) << PD;
1151	}
1152
1153	/// Check if the type is allowed to be used for the current target.
1154	void checkTypeSupport(QualType Ty, SourceLocation Loc,
1155	ValueDecl D = nullptr*);
1156
1157	/// ImpCastExprToType - If Expr is not of type 'Type', insert an implicit
1158	/// cast. If there is already an implicit cast, merge into the existing one.
1159	/// If isLvalue, the result of the cast is an lvalue.
1160	ExprResult ImpCastExprToType(
1161	Expr *E, QualType Type, CastKind CK, ExprValueKind VK = VK_PRValue,
1162	const CXXCastPath BasePath = nullptr*,
1163	CheckedConversionKind CCK = CheckedConversionKind::Implicit);
1164
1165	/// ScalarTypeToBooleanCastKind - Returns the cast kind corresponding
1166	/// to the conversion from scalar type ScalarTy to the Boolean type.
1167	static CastKind ScalarTypeToBooleanCastKind(QualType ScalarTy);
1168
1169	/// If \p AllowLambda is true, treat lambda as function.
1170	DeclContext getFunctionLevelDeclContext(bool* AllowLambda = false) const;
1171
1172	/// Returns a pointer to the innermost enclosing function, or nullptr if the
1173	/// current context is not inside a function. If \p AllowLambda is true,
1174	/// this can return the call operator of an enclosing lambda, otherwise
1175	/// lambdas are skipped when looking for an enclosing function.
1176	FunctionDecl getCurFunctionDecl(bool* AllowLambda = false) const;
1177
1178	/// getCurMethodDecl - If inside of a method body, this returns a pointer to
1179	/// the method decl for the method being parsed. If we're currently
1180	/// in a 'block', this returns the containing context.
1181	ObjCMethodDecl *getCurMethodDecl();
1182
1183	/// getCurFunctionOrMethodDecl - Return the Decl for the current ObjC method
1184	/// or C function we're in, otherwise return null. If we're currently
1185	/// in a 'block', this returns the containing context.
1186	NamedDecl getCurFunctionOrMethodDecl() const*;
1187
1188	/// Warn if we're implicitly casting from a _Nullable pointer type to a
1189	/// _Nonnull one.
1190	void diagnoseNullableToNonnullConversion(QualType DstType, QualType SrcType,
1191	SourceLocation Loc);
1192
1193	/// Warn when implicitly casting 0 to nullptr.
1194	void diagnoseZeroToNullptrConversion(CastKind Kind, const Expr *E);
1195
1196	/// Warn when implicitly changing function effects.
1197	void diagnoseFunctionEffectConversion(QualType DstType, QualType SrcType,
1198	SourceLocation Loc);
1199
1200	/// makeUnavailableInSystemHeader - There is an error in the current
1201	/// context. If we're still in a system header, and we can plausibly
1202	/// make the relevant declaration unavailable instead of erroring, do
1203	/// so and return true.
1204	bool makeUnavailableInSystemHeader(SourceLocation loc,
1205	UnavailableAttr::ImplicitReason reason);
1206
1207	/// Retrieve a suitable printing policy for diagnostics.
1208	PrintingPolicy getPrintingPolicy() const {
1209	return getPrintingPolicy(Ctx: Context, PP);
1210	}
1211
1212	/// Retrieve a suitable printing policy for diagnostics.
1213	static PrintingPolicy getPrintingPolicy(const ASTContext &Ctx,
1214	const Preprocessor &PP);
1215
1216	/// Scope actions.
1217	void ActOnTranslationUnitScope(Scope *S);
1218
1219	/// Determine whether \param D is function like (function or function
1220	/// template) for parsing.
1221	bool isDeclaratorFunctionLike(Declarator &D);
1222
1223	/// The maximum alignment, same as in llvm::Value. We duplicate them here
1224	/// because that allows us not to duplicate the constants in clang code,
1225	/// which we must to since we can't directly use the llvm constants.
1226	/// The value is verified against llvm here: lib/CodeGen/CGDecl.cpp
1227	///
1228	/// This is the greatest alignment value supported by load, store, and alloca
1229	/// instructions, and global values.
1230	static const unsigned MaxAlignmentExponent = `32`;
1231	static const uint64_t MaximumAlignment = `1ull` << MaxAlignmentExponent;
1232
1233	/// Flag indicating whether or not to collect detailed statistics.
1234	bool CollectStats;
1235
1236	std::unique_ptr<sema::FunctionScopeInfo> CachedFunctionScope;
1237
1238	/// Stack containing information about each of the nested
1239	/// function, block, and method scopes that are currently active.
1240	SmallVector<sema::FunctionScopeInfo *, `4`> FunctionScopes;
1241
1242	/// The index of the first FunctionScope that corresponds to the current
1243	/// context.
1244	unsigned FunctionScopesStart = `0`;
1245
1246	/// Track the number of currently active capturing scopes.
1247	unsigned CapturingFunctionScopes = `0`;
1248
1249	llvm::BumpPtrAllocator BumpAlloc;
1250
1251	/// The kind of translation unit we are processing.
1252	///
1253	/// When we're processing a complete translation unit, Sema will perform
1254	/// end-of-translation-unit semantic tasks (such as creating
1255	/// initializers for tentative definitions in C) once parsing has
1256	/// completed. Modules and precompiled headers perform different kinds of
1257	/// checks.
1258	const TranslationUnitKind TUKind;
1259
1260	/// Translation Unit Scope - useful to Objective-C actions that need
1261	/// to lookup file scope declarations in the "ordinary" C decl namespace.
1262	/// For example, user-defined classes, built-in "id" type, etc.
1263	Scope *TUScope;
1264
1265	void incrementMSManglingNumber() const {
1266	return CurScope->incrementMSManglingNumber();
1267	}
1268
1269	/// Try to recover by turning the given expression into a
1270	/// call. Returns true if recovery was attempted or an error was
1271	/// emitted; this may also leave the ExprResult invalid.
1272	bool tryToRecoverWithCall(ExprResult &E, const PartialDiagnostic &PD,
1273	bool ForceComplain = false,
1274	bool (IsPlausibleResult)(QualType) = nullptr*);
1275
1276	// Adds implicit lifetime bound attribute for implicit this to its
1277	// TypeSourceInfo.
1278	void addLifetimeBoundToImplicitThis(CXXMethodDecl *MD);
1279
1280	/// Figure out if an expression could be turned into a call.
1281	///
1282	/// Use this when trying to recover from an error where the programmer may
1283	/// have written just the name of a function instead of actually calling it.
1284	///
1285	/// \param E - The expression to examine.
1286	/// \param ZeroArgCallReturnTy - If the expression can be turned into a call
1287	/// with no arguments, this parameter is set to the type returned by such a
1288	/// call; otherwise, it is set to an empty QualType.
1289	/// \param OverloadSet - If the expression is an overloaded function
1290	/// name, this parameter is populated with the decls of the various
1291	/// overloads.
1292	bool tryExprAsCall(Expr &E, QualType &ZeroArgCallReturnTy,
1293	UnresolvedSetImpl &NonTemplateOverloads);
1294
1295	typedef OpaquePtr<DeclGroupRef> DeclGroupPtrTy;
1296	typedef OpaquePtr<TemplateName> TemplateTy;
1297	typedef OpaquePtr<QualType> TypeTy;
1298
1299	OpenCLOptions OpenCLFeatures;
1300	FPOptions CurFPFeatures;
1301
1302	const LangOptions &LangOpts;
1303	Preprocessor &PP;
1304	ASTContext &Context;
1305	ASTConsumer &Consumer;
1306	DiagnosticsEngine &Diags;
1307	SourceManager &SourceMgr;
1308	api_notes::APINotesManager APINotes;
1309
1310	std::unique_ptr<APINotesSelectorDiagnosticState> APINotesSelectorDiagnostics;
1311
1312	/// A RAII object to enter scope of a compound statement.
1313	class CompoundScopeRAII {
1314	public:
1315	CompoundScopeRAII(Sema &S, bool IsStmtExpr = false) : S(S) {
1316	S.ActOnStartOfCompoundStmt(IsStmtExpr);
1317	}
1318
1319	~CompoundScopeRAII() { S.ActOnFinishOfCompoundStmt(); }
1320	CompoundScopeRAII(const CompoundScopeRAII &) = delete;
1321	CompoundScopeRAII &operator=(const CompoundScopeRAII &) = delete;
1322
1323	private:
1324	Sema &S;
1325	};
1326
1327	/// An RAII helper that pops function a function scope on exit.
1328	struct FunctionScopeRAII {
1329	Sema &S;
1330	bool Active;
1331	FunctionScopeRAII(Sema &S) : S(S), Active(true) {}
1332	~FunctionScopeRAII() {
1333	if (Active)
1334	S.PopFunctionScopeInfo();
1335	}
1336	void disable() { Active = false; }
1337	};
1338
1339	sema::FunctionScopeInfo getCurFunction() const* {
1340	return FunctionScopes.empty() ? nullptr : FunctionScopes.back();
1341	}
1342
1343	/// Worker object for performing CFG-based warnings.
1344	sema::AnalysisBasedWarnings AnalysisWarnings;
1345	threadSafety::BeforeSet *ThreadSafetyDeclCache;
1346
1347	/// Callback to the parser to parse templated functions when needed.
1348	typedef void LateTemplateParserCB(void *P, LateParsedTemplate &LPT);
1349	LateTemplateParserCB *LateTemplateParser;
1350	void *OpaqueParser;
1351
1352	void SetLateTemplateParser(LateTemplateParserCB LTP, void* *P) {
1353	LateTemplateParser = LTP;
1354	OpaqueParser = P;
1355	}
1356
1357	/// Callback to the parser to parse a type expressed as a string.
1358	std::function<TypeResult(StringRef, StringRef, SourceLocation)>
1359	ParseTypeFromStringCallback;
1360
1361	/// VAListTagName - The declaration name corresponding to __va_list_tag.
1362	/// This is used as part of a hack to omit that class from ADL results.
1363	DeclarationName VAListTagName;
1364
1365	/// Is the last error level diagnostic immediate. This is used to determined
1366	/// whether the next info diagnostic should be immediate.
1367	bool IsLastErrorImmediate = true;
1368
1369	/// Track if we're currently analyzing overflow behavior types in assignment
1370	/// context.
1371	bool InOverflowBehaviorAssignmentContext = false;
1372
1373	class DelayedDiagnostics;
1374
1375	class DelayedDiagnosticsState {
1376	sema::DelayedDiagnosticPool SavedPool = nullptr*;
1377	friend class Sema::DelayedDiagnostics;
1378	};
1379	typedef DelayedDiagnosticsState ParsingDeclState;
1380	typedef DelayedDiagnosticsState ProcessingContextState;
1381
1382	/// A class which encapsulates the logic for delaying diagnostics
1383	/// during parsing and other processing.
1384	class DelayedDiagnostics {
1385	/// The current pool of diagnostics into which delayed
1386	/// diagnostics should go.
1387	sema::DelayedDiagnosticPool CurPool = nullptr*;
1388
1389	public:
1390	DelayedDiagnostics() = default;
1391
1392	/// Adds a delayed diagnostic.
1393	void add(const sema::DelayedDiagnostic &diag); // in DelayedDiagnostic.h
1394
1395	/// Determines whether diagnostics should be delayed.
1396	bool shouldDelayDiagnostics() { return CurPool != nullptr; }
1397
1398	/// Returns the current delayed-diagnostics pool.
1399	sema::DelayedDiagnosticPool getCurrentPool() const* { return CurPool; }
1400
1401	/// Enter a new scope. Access and deprecation diagnostics will be
1402	/// collected in this pool.
1403	DelayedDiagnosticsState push(sema::DelayedDiagnosticPool &pool) {
1404	DelayedDiagnosticsState state;
1405	state.SavedPool = CurPool;
1406	CurPool = &pool;
1407	return state;
1408	}
1409
1410	/// Leave a delayed-diagnostic state that was previously pushed.
1411	/// Do not emit any of the diagnostics. This is performed as part
1412	/// of the bookkeeping of popping a pool "properly".
1413	void popWithoutEmitting(DelayedDiagnosticsState state) {
1414	CurPool = state.SavedPool;
1415	}
1416
1417	/// Enter a new scope where access and deprecation diagnostics are
1418	/// not delayed.
1419	DelayedDiagnosticsState pushUndelayed() {
1420	DelayedDiagnosticsState state;
1421	state.SavedPool = CurPool;
1422	CurPool = nullptr;
1423	return state;
1424	}
1425
1426	/// Undo a previous pushUndelayed().
1427	void popUndelayed(DelayedDiagnosticsState state) {
1428	assert(CurPool == nullptr);
1429	CurPool = state.SavedPool;
1430	}
1431	} DelayedDiagnostics;
1432
1433	ParsingDeclState PushParsingDeclaration(sema::DelayedDiagnosticPool &pool) {
1434	return DelayedDiagnostics.push(pool);
1435	}
1436
1437	/// Diagnostics that are emitted only if we discover that the given function
1438	/// must be codegen'ed. Because handling these correctly adds overhead to
1439	/// compilation, this is currently only used for offload languages like CUDA,
1440	/// OpenMP, and SYCL.
1441	SemaDiagnosticBuilder::DeferredDiagnosticsType DeviceDeferredDiags;
1442
1443	/// CurContext - This is the current declaration context of parsing.
1444	DeclContext *CurContext;
1445
1446	SemaAMDGPU &AMDGPU() {
1447	assert(AMDGPUPtr);
1448	return *AMDGPUPtr;
1449	}
1450
1451	SemaARM &ARM() {
1452	assert(ARMPtr);
1453	return *ARMPtr;
1454	}
1455
1456	SemaAVR &AVR() {
1457	assert(AVRPtr);
1458	return *AVRPtr;
1459	}
1460
1461	SemaBPF &BPF() {
1462	assert(BPFPtr);
1463	return *BPFPtr;
1464	}
1465
1466	SemaCodeCompletion &CodeCompletion() {
1467	assert(CodeCompletionPtr);
1468	return *CodeCompletionPtr;
1469	}
1470
1471	SemaCUDA &CUDA() {
1472	assert(CUDAPtr);
1473	return *CUDAPtr;
1474	}
1475
1476	SemaDirectX &DirectX() {
1477	assert(DirectXPtr);
1478	return *DirectXPtr;
1479	}
1480
1481	SemaHLSL &HLSL() {
1482	assert(HLSLPtr);
1483	return *HLSLPtr;
1484	}
1485
1486	SemaHexagon &Hexagon() {
1487	assert(HexagonPtr);
1488	return *HexagonPtr;
1489	}
1490
1491	SemaLoongArch &LoongArch() {
1492	assert(LoongArchPtr);
1493	return *LoongArchPtr;
1494	}
1495
1496	SemaM68k &M68k() {
1497	assert(M68kPtr);
1498	return *M68kPtr;
1499	}
1500
1501	SemaMIPS &MIPS() {
1502	assert(MIPSPtr);
1503	return *MIPSPtr;
1504	}
1505
1506	SemaMSP430 &MSP430() {
1507	assert(MSP430Ptr);
1508	return *MSP430Ptr;
1509	}
1510
1511	SemaNVPTX &NVPTX() {
1512	assert(NVPTXPtr);
1513	return *NVPTXPtr;
1514	}
1515
1516	SemaObjC &ObjC() {
1517	assert(ObjCPtr);
1518	return *ObjCPtr;
1519	}
1520
1521	SemaOpenACC &OpenACC() {
1522	assert(OpenACCPtr);
1523	return *OpenACCPtr;
1524	}
1525
1526	SemaOpenCL &OpenCL() {
1527	assert(OpenCLPtr);
1528	return *OpenCLPtr;
1529	}
1530
1531	SemaOpenMP &OpenMP() {
1532	assert(OpenMPPtr && "SemaOpenMP is dead");
1533	return *OpenMPPtr;
1534	}
1535
1536	SemaPPC &PPC() {
1537	assert(PPCPtr);
1538	return *PPCPtr;
1539	}
1540
1541	SemaPseudoObject &PseudoObject() {
1542	assert(PseudoObjectPtr);
1543	return *PseudoObjectPtr;
1544	}
1545
1546	SemaRISCV &RISCV() {
1547	assert(RISCVPtr);
1548	return *RISCVPtr;
1549	}
1550
1551	SemaSPIRV &SPIRV() {
1552	assert(SPIRVPtr);
1553	return *SPIRVPtr;
1554	}
1555
1556	SemaSYCL &SYCL() {
1557	assert(SYCLPtr);
1558	return *SYCLPtr;
1559	}
1560
1561	SemaSwift &Swift() {
1562	assert(SwiftPtr);
1563	return *SwiftPtr;
1564	}
1565
1566	SemaSystemZ &SystemZ() {
1567	assert(SystemZPtr);
1568	return *SystemZPtr;
1569	}
1570
1571	SemaWasm &Wasm() {
1572	assert(WasmPtr);
1573	return *WasmPtr;
1574	}
1575
1576	SemaX86 &X86() {
1577	assert(X86Ptr);
1578	return *X86Ptr;
1579	}
1580
1581	/// Source of additional semantic information.
1582	IntrusiveRefCntPtr<ExternalSemaSource> ExternalSource;
1583
1584	protected:
1585	friend class Parser;
1586	friend class InitializationSequence;
1587	friend class ASTReader;
1588	friend class ASTDeclReader;
1589	friend class ASTWriter;
1590
1591	private:
1592	std::optional<std::unique_ptr<DarwinSDKInfo>> CachedDarwinSDKInfo;
1593	bool WarnedDarwinSDKInfoMissing = false;
1594
1595	StackExhaustionHandler StackHandler;
1596
1597	Sema(const Sema &) = delete;
1598	void operator=(const Sema &) = delete;
1599
1600	/// The handler for the FileChanged preprocessor events.
1601	///
1602	/// Used for diagnostics that implement custom semantic analysis for #include
1603	/// directives, like -Wpragma-pack.
1604	sema::SemaPPCallbacks *SemaPPCallbackHandler;
1605
1606	/// The parser's current scope.
1607	///
1608	/// The parser maintains this state here.
1609	Scope *CurScope;
1610
1611	mutable IdentifierInfo *Ident_super;
1612
1613	std::unique_ptr<SemaAMDGPU> AMDGPUPtr;
1614	std::unique_ptr<SemaARM> ARMPtr;
1615	std::unique_ptr<SemaAVR> AVRPtr;
1616	std::unique_ptr<SemaBPF> BPFPtr;
1617	std::unique_ptr<SemaCodeCompletion> CodeCompletionPtr;
1618	std::unique_ptr<SemaCUDA> CUDAPtr;
1619	std::unique_ptr<SemaDirectX> DirectXPtr;
1620	std::unique_ptr<SemaHLSL> HLSLPtr;
1621	std::unique_ptr<SemaHexagon> HexagonPtr;
1622	std::unique_ptr<SemaLoongArch> LoongArchPtr;
1623	std::unique_ptr<SemaM68k> M68kPtr;
1624	std::unique_ptr<SemaMIPS> MIPSPtr;
1625	std::unique_ptr<SemaMSP430> MSP430Ptr;
1626	std::unique_ptr<SemaNVPTX> NVPTXPtr;
1627	std::unique_ptr<SemaObjC> ObjCPtr;
1628	std::unique_ptr<SemaOpenACC> OpenACCPtr;
1629	std::unique_ptr<SemaOpenCL> OpenCLPtr;
1630	std::unique_ptr<SemaOpenMP> OpenMPPtr;
1631	std::unique_ptr<SemaPPC> PPCPtr;
1632	std::unique_ptr<SemaPseudoObject> PseudoObjectPtr;
1633	std::unique_ptr<SemaRISCV> RISCVPtr;
1634	std::unique_ptr<SemaSPIRV> SPIRVPtr;
1635	std::unique_ptr<SemaSYCL> SYCLPtr;
1636	std::unique_ptr<SemaSwift> SwiftPtr;
1637	std::unique_ptr<SemaSystemZ> SystemZPtr;
1638	std::unique_ptr<SemaWasm> WasmPtr;
1639	std::unique_ptr<SemaX86> X86Ptr;
1640
1641	///@}
1642
1643	//
1644	//
1645	// -------------------------------------------------------------------------
1646	//
1647	//
1648
1649	/// \name API Notes
1650	/// Implementations are in SemaAPINotes.cpp
1651	///@{
1652
1653	public:
1654	/// Map any API notes provided for this declaration to attributes on the
1655	/// declaration.
1656	///
1657	/// Triggered by declaration-attribute processing.
1658	void ProcessAPINotes(Decl *D);
1659	/// Apply the 'Nullability:' annotation to the specified declaration
1660	void ApplyNullability(Decl *D, NullabilityKind Nullability);
1661	/// Apply the 'Type:' annotation to the specified declaration
1662	void ApplyAPINotesType(Decl *D, StringRef TypeString);
1663
1664	/// Diagnose exact API notes selectors that were not matched by any
1665	/// declaration processed in this translation unit.
1666	void DiagnoseUnusedAPINotesSelectors();
1667
1668	/// Whether APINotes should be gathered for all applicable Swift language
1669	/// versions, without being applied. Leaving clients of the current module
1670	/// to select and apply the correct version.
1671	bool captureSwiftVersionIndependentAPINotes() {
1672	return APINotes.captureVersionIndependentSwift();
1673	}
1674	///@}
1675
1676	//
1677	//
1678	// -------------------------------------------------------------------------
1679	//
1680	//
1681
1682	/// \name C++ Access Control
1683	/// Implementations are in SemaAccess.cpp
1684	///@{
1685
1686	public:
1687	enum AccessResult {
1688	AR_accessible,
1689	AR_inaccessible,
1690	AR_dependent,
1691	AR_delayed
1692	};
1693
1694	/// SetMemberAccessSpecifier - Set the access specifier of a member.
1695	/// Returns true on error (when the previous member decl access specifier
1696	/// is different from the new member decl access specifier).
1697	bool SetMemberAccessSpecifier(NamedDecl *MemberDecl,
1698	NamedDecl *PrevMemberDecl,
1699	AccessSpecifier LexicalAS);
1700
1701	/// Perform access-control checking on a previously-unresolved member
1702	/// access which has now been resolved to a member.
1703	AccessResult CheckUnresolvedMemberAccess(UnresolvedMemberExpr *E,
1704	DeclAccessPair FoundDecl);
1705	AccessResult CheckUnresolvedLookupAccess(UnresolvedLookupExpr *E,
1706	DeclAccessPair FoundDecl);
1707
1708	/// Checks access to an overloaded operator new or delete.
1709	AccessResult CheckAllocationAccess(SourceLocation OperatorLoc,
1710	SourceRange PlacementRange,
1711	CXXRecordDecl *NamingClass,
1712	DeclAccessPair FoundDecl,
1713	bool Diagnose = true);
1714
1715	/// Checks access to a constructor.
1716	AccessResult CheckConstructorAccess(SourceLocation Loc, CXXConstructorDecl *D,
1717	DeclAccessPair FoundDecl,
1718	const InitializedEntity &Entity,
1719	bool IsCopyBindingRefToTemp = false);
1720
1721	/// Checks access to a constructor.
1722	AccessResult CheckConstructorAccess(SourceLocation Loc, CXXConstructorDecl *D,
1723	DeclAccessPair FoundDecl,
1724	const InitializedEntity &Entity,
1725	const PartialDiagnostic &PDiag);
1726	AccessResult CheckDestructorAccess(SourceLocation Loc,
1727	CXXDestructorDecl *Dtor,
1728	const PartialDiagnostic &PDiag,
1729	QualType objectType = QualType ());
1730
1731	/// Checks access to the target of a friend declaration.
1732	AccessResult CheckFriendAccess(NamedDecl *D);
1733
1734	/// Checks access to a member.
1735	AccessResult CheckMemberAccess(SourceLocation UseLoc,
1736	CXXRecordDecl *NamingClass,
1737	DeclAccessPair Found);
1738
1739	/// Checks implicit access to a member in a structured binding.
1740	AccessResult
1741	CheckStructuredBindingMemberAccess(SourceLocation UseLoc,
1742	CXXRecordDecl *DecomposedClass,
1743	DeclAccessPair Field);
1744	AccessResult CheckMemberOperatorAccess(SourceLocation Loc, Expr *ObjectExpr,
1745	const SourceRange &,
1746	DeclAccessPair FoundDecl);
1747
1748	/// Checks access to an overloaded member operator, including
1749	/// conversion operators.
1750	AccessResult CheckMemberOperatorAccess(SourceLocation Loc, Expr *ObjectExpr,
1751	Expr *ArgExpr,
1752	DeclAccessPair FoundDecl);
1753	AccessResult CheckMemberOperatorAccess(SourceLocation Loc, Expr *ObjectExpr,
1754	ArrayRef<Expr *> ArgExprs,
1755	DeclAccessPair FoundDecl);
1756	AccessResult CheckAddressOfMemberAccess(Expr *OvlExpr,
1757	DeclAccessPair FoundDecl);
1758
1759	/// Checks access for a hierarchy conversion.
1760	///
1761	/// \param ForceCheck true if this check should be performed even if access
1762	/// control is disabled; some things rely on this for semantics
1763	/// \param ForceUnprivileged true if this check should proceed as if the
1764	/// context had no special privileges
1765	AccessResult CheckBaseClassAccess(SourceLocation AccessLoc, QualType Base,
1766	QualType Derived, const CXXBasePath &Path,
1767	unsigned DiagID, bool ForceCheck = false,
1768	bool ForceUnprivileged = false);
1769
1770	AccessResult CheckBaseClassAccess(
1771	SourceLocation AccessLoc, CXXRecordDecl Base, CXXRecordDecl Derived,
1772	const CXXBasePath &Path, unsigned DiagID,
1773	llvm::function_ref<void(PartialDiagnostic &PD)> SetupPDiag,
1774	bool ForceCheck = false, bool ForceUnprivileged = false);
1775
1776	/// Checks access to all the declarations in the given result set.
1777	void CheckLookupAccess(const LookupResult &R);
1778
1779	/// Checks access to Target from the given class. The check will take access
1780	/// specifiers into account, but no member access expressions and such.
1781	///
1782	/// \param Target the declaration to check if it can be accessed
1783	/// \param NamingClass the class in which the lookup was started.
1784	/// \param BaseType type of the left side of member access expression.
1785	/// \p BaseType and \p NamingClass are used for C++ access control.
1786	/// Depending on the lookup case, they should be set to the following:
1787	/// - lhs.target (member access without a qualifier):
1788	/// \p BaseType and \p NamingClass are both the type of 'lhs'.
1789	/// - lhs.X::target (member access with a qualifier):
1790	/// BaseType is the type of 'lhs', NamingClass is 'X'
1791	/// - X::target (qualified lookup without member access):
1792	/// BaseType is null, NamingClass is 'X'.
1793	/// - target (unqualified lookup).
1794	/// BaseType is null, NamingClass is the parent class of 'target'.
1795	/// \return true if the Target is accessible from the Class, false otherwise.
1796	bool IsSimplyAccessible(NamedDecl Decl, CXXRecordDecl NamingClass,
1797	QualType BaseType);
1798
1799	/// Is the given member accessible for the purposes of deciding whether to
1800	/// define a special member function as deleted?
1801	bool isMemberAccessibleForDeletion(CXXRecordDecl *NamingClass,
1802	DeclAccessPair Found, QualType ObjectType,
1803	SourceLocation Loc,
1804	const PartialDiagnostic &Diag);
1805	bool isMemberAccessibleForDeletion(CXXRecordDecl *NamingClass,
1806	DeclAccessPair Found,
1807	QualType ObjectType) {
1808	return isMemberAccessibleForDeletion(NamingClass, Found, ObjectType,
1809	Loc: SourceLocation (), Diag: PDiag());
1810	}
1811
1812	void HandleDependentAccessCheck(
1813	const DependentDiagnostic &DD,
1814	const MultiLevelTemplateArgumentList &TemplateArgs);
1815	void HandleDelayedAccessCheck(sema::DelayedDiagnostic &DD, Decl *Ctx);
1816
1817	///@}
1818
1819	//
1820	//
1821	// -------------------------------------------------------------------------
1822	//
1823	//
1824
1825	/// \name Attributes
1826	/// Implementations are in SemaAttr.cpp
1827	///@{
1828
1829	public:
1830	/// Controls member pointer representation format under the MS ABI.
1831	LangOptions::PragmaMSPointersToMembersKind
1832	MSPointerToMemberRepresentationMethod;
1833
1834	bool MSStructPragmaOn; // True when \#pragma ms_struct on
1835
1836	/// Source location for newly created implicit MSInheritanceAttrs
1837	SourceLocation ImplicitMSInheritanceAttrLoc;
1838
1839	struct PragmaClangSection {
1840	std::string SectionName;
1841	bool Valid = false;
1842	SourceLocation PragmaLocation;
1843	};
1844
1845	PragmaClangSection PragmaClangBSSSection;
1846	PragmaClangSection PragmaClangDataSection;
1847	PragmaClangSection PragmaClangRodataSection;
1848	PragmaClangSection PragmaClangRelroSection;
1849	PragmaClangSection PragmaClangTextSection;
1850
1851	enum PragmaMsStackAction {
1852	PSK_Reset = `0x0`, // #pragma ()
1853	PSK_Set = `0x1`, // #pragma (value)
1854	PSK_Push = `0x2`, // #pragma (push[, id])
1855	PSK_Pop = `0x4`, // #pragma (pop[, id])
1856	PSK_Show = `0x8`, // #pragma (show) -- only for "pack"!
1857	PSK_Push_Set = PSK_Push \| PSK_Set, // #pragma (push[, id], value)
1858	PSK_Pop_Set = PSK_Pop \| PSK_Set, // #pragma (pop[, id], value)
1859	};
1860
1861	struct PragmaPackInfo {
1862	PragmaMsStackAction Action;
1863	StringRef SlotLabel;
1864	Token Alignment;
1865	};
1866
1867	// #pragma pack and align.
1868	class AlignPackInfo {
1869	public:
1870	// `Native` represents default align mode, which may vary based on the
1871	// platform.
1872	enum Mode : unsigned char { Native, Natural, Packed, Mac68k };
1873
1874	// #pragma pack info constructor
1875	AlignPackInfo(AlignPackInfo::Mode M, unsigned Num, bool IsXL)
1876	: PackAttr(true), AlignMode(M), PackNumber(Num), XLStack(IsXL) {
1877	assert(Num == PackNumber && "The pack number has been truncated.");
1878	}
1879
1880	// #pragma align info constructor
1881	AlignPackInfo(AlignPackInfo::Mode M, bool IsXL)
1882	: PackAttr(false), AlignMode(M),
1883	PackNumber(M == Packed ? `1` : UninitPackVal), XLStack(IsXL) {}
1884
1885	explicit AlignPackInfo(bool IsXL) : AlignPackInfo (Native, IsXL) {}
1886
1887	AlignPackInfo() : AlignPackInfo (Native, false) {}
1888
1889	// When a AlignPackInfo itself cannot be used, this returns an 32-bit
1890	// integer encoding for it. This should only be passed to
1891	// AlignPackInfo::getFromRawEncoding, it should not be inspected directly.
1892	static uint32_t getRawEncoding(const AlignPackInfo &Info) {
1893	std::uint32_t Encoding{};
1894	if (Info.IsXLStack())
1895	Encoding \|= IsXLMask;
1896
1897	Encoding \|= static_cast<uint32_t>(Info.getAlignMode()) << `1`;
1898
1899	if (Info.IsPackAttr())
1900	Encoding \|= PackAttrMask;
1901
1902	Encoding \|= static_cast<uint32_t>(Info.getPackNumber()) << `4`;
1903
1904	return Encoding;
1905	}
1906
1907	static AlignPackInfo getFromRawEncoding(unsigned Encoding) {
1908	bool IsXL = static_cast<bool>(Encoding & IsXLMask);
1909	AlignPackInfo::Mode M =
1910	static_cast<AlignPackInfo::Mode>((Encoding & AlignModeMask) >> `1`);
1911	int PackNumber = (Encoding & PackNumMask) >> `4`;
1912
1913	if (Encoding & PackAttrMask)
1914	return AlignPackInfo (M, PackNumber, IsXL);
1915
1916	return AlignPackInfo (M, IsXL);
1917	}
1918
1919	bool IsPackAttr() const { return PackAttr; }
1920
1921	bool IsAlignAttr() const { return !PackAttr; }
1922
1923	Mode getAlignMode() const { return AlignMode; }
1924
1925	unsigned getPackNumber() const { return PackNumber; }
1926
1927	bool IsPackSet() const {
1928	// #pragma align, #pragma pack(), and #pragma pack(0) do not set the pack
1929	// attriute on a decl.
1930	return PackNumber != UninitPackVal && PackNumber != `0`;
1931	}
1932
1933	bool IsXLStack() const { return XLStack; }
1934
1935	bool operator==(const AlignPackInfo &Info) const {
1936	return std::tie(args: AlignMode, args: PackNumber, args: PackAttr, args: XLStack) ==
1937	std::tie(args: Info.AlignMode, args: Info.PackNumber, args: Info.PackAttr,
1938	args: Info.XLStack);
1939	}
1940
1941	bool operator!=(const AlignPackInfo &Info) const {
1942	return !(*this == Info);
1943	}
1944
1945	private:
1946	/// \brief True if this is a pragma pack attribute,
1947	/// not a pragma align attribute.
1948	bool PackAttr;
1949
1950	/// \brief The alignment mode that is in effect.
1951	Mode AlignMode;
1952
1953	/// \brief The pack number of the stack.
1954	unsigned char PackNumber;
1955
1956	/// \brief True if it is a XL #pragma align/pack stack.
1957	bool XLStack;
1958
1959	/// \brief Uninitialized pack value.
1960	static constexpr unsigned char UninitPackVal = -`1`;
1961
1962	// Masks to encode and decode an AlignPackInfo.
1963	static constexpr uint32_t IsXLMask{`0x0000'0001`};
1964	static constexpr uint32_t AlignModeMask{`0x0000'0006`};
1965	static constexpr uint32_t PackAttrMask{`0x00000'0008`};
1966	static constexpr uint32_t PackNumMask{`0x0000'01F0`};
1967	};
1968
1969	template <typename ValueType> struct PragmaStack {
1970	struct Slot {
1971	llvm::StringRef StackSlotLabel;
1972	ValueType Value;
1973	SourceLocation PragmaLocation;
1974	SourceLocation PragmaPushLocation;
1975	Slot(llvm::StringRef StackSlotLabel, ValueType Value,
1976	SourceLocation PragmaLocation, SourceLocation PragmaPushLocation)
1977	: StackSlotLabel (StackSlotLabel), Value(Value),
1978	PragmaLocation (PragmaLocation),
1979	PragmaPushLocation (PragmaPushLocation) {}
1980	};
1981
1982	void Act(SourceLocation PragmaLocation, PragmaMsStackAction Action,
1983	llvm::StringRef StackSlotLabel, ValueType Value) {
1984	if (Action == PSK_Reset) {
1985	CurrentValue = DefaultValue;
1986	CurrentPragmaLocation = PragmaLocation;
1987	return;
1988	}
1989	if (Action & PSK_Push)
1990	Stack.emplace_back(StackSlotLabel, CurrentValue, CurrentPragmaLocation,
1991	PragmaLocation);
1992	else if (Action & PSK_Pop) {
1993	if (!StackSlotLabel.empty()) {
1994	// If we've got a label, try to find it and jump there.
1995	auto I = llvm::find_if(llvm::reverse(Stack), [&](const Slot &x) {
1996	return x.StackSlotLabel == StackSlotLabel;
1997	});
1998	// If we found the label so pop from there.
1999	if (I != Stack.rend()) {
2000	CurrentValue = I->Value;
2001	CurrentPragmaLocation = I->PragmaLocation;
2002	Stack.erase(std::prev(I.base()), Stack.end());
2003	}
2004	} else if (!Stack.empty()) {
2005	// We do not have a label, just pop the last entry.
2006	CurrentValue = Stack.back().Value;
2007	CurrentPragmaLocation = Stack.back().PragmaLocation;
2008	Stack.pop_back();
2009	}
2010	}
2011	if (Action & PSK_Set) {
2012	CurrentValue = Value;
2013	CurrentPragmaLocation = PragmaLocation;
2014	}
2015	}
2016
2017	// MSVC seems to add artificial slots to #pragma stacks on entering a C++
2018	// method body to restore the stacks on exit, so it works like this:
2019	//
2020	// struct S {
2021	// #pragma <name>(push, InternalPragmaSlot, <current_pragma_value>)
2022	// void Method {}
2023	// #pragma <name>(pop, InternalPragmaSlot)
2024	// };
2025	//
2026	// It works even with #pragma vtordisp, although MSVC doesn't support
2027	// #pragma vtordisp(push [, id], n)
2028	// syntax.
2029	//
2030	// Push / pop a named sentinel slot.
2031	void SentinelAction(PragmaMsStackAction Action, StringRef Label) {
2032	assert((Action == PSK_Push \|\| Action == PSK_Pop) &&
2033	"Can only push / pop #pragma stack sentinels!");
2034	Act(PragmaLocation: CurrentPragmaLocation, Action, StackSlotLabel: Label, Value: CurrentValue);
2035	}
2036
2037	// Constructors.
2038	explicit PragmaStack(const ValueType &Default)
2039	: DefaultValue(Default), CurrentValue(Default) {}
2040
2041	bool hasValue() const { return CurrentValue != DefaultValue; }
2042
2043	SmallVector<Slot, `2`> Stack;
2044	ValueType DefaultValue; // Value used for PSK_Reset action.
2045	ValueType CurrentValue;
2046	SourceLocation CurrentPragmaLocation;
2047	};
2048	// FIXME: We should serialize / deserialize these if they occur in a PCH (but
2049	// we shouldn't do so if they're in a module).
2050
2051	/// Whether to insert vtordisps prior to virtual bases in the Microsoft
2052	/// C++ ABI. Possible values are 0, 1, and 2, which mean:
2053	///
2054	/// 0: Suppress all vtordisps
2055	/// 1: Insert vtordisps in the presence of vbase overrides and non-trivial
2056	/// structors
2057	/// 2: Always insert vtordisps to support RTTI on partially constructed
2058	/// objects
2059	PragmaStack<MSVtorDispMode> VtorDispStack;
2060	PragmaStack<AlignPackInfo> AlignPackStack;
2061	// The current #pragma align/pack values and locations at each #include.
2062	struct AlignPackIncludeState {
2063	AlignPackInfo CurrentValue;
2064	SourceLocation CurrentPragmaLocation;
2065	bool HasNonDefaultValue, ShouldWarnOnInclude;
2066	};
2067	SmallVector<AlignPackIncludeState, `8`> AlignPackIncludeStack;
2068	// Segment #pragmas.
2069	PragmaStack<StringLiteral *> DataSegStack;
2070	PragmaStack<StringLiteral *> BSSSegStack;
2071	PragmaStack<StringLiteral *> ConstSegStack;
2072	PragmaStack<StringLiteral *> CodeSegStack;
2073
2074	// #pragma strict_gs_check.
2075	PragmaStack<bool> StrictGuardStackCheckStack;
2076
2077	// This stack tracks the current state of Sema.CurFPFeatures.
2078	PragmaStack<FPOptionsOverride> FpPragmaStack;
2079	FPOptionsOverride CurFPFeatureOverrides() {
2080	FPOptionsOverride result;
2081	if (!FpPragmaStack.hasValue()) {
2082	result = FPOptionsOverride ();
2083	} else {
2084	result = FpPragmaStack.CurrentValue;
2085	}
2086	return result;
2087	}
2088
2089	enum PragmaSectionKind {
2090	PSK_DataSeg,
2091	PSK_BSSSeg,
2092	PSK_ConstSeg,
2093	PSK_CodeSeg,
2094	};
2095
2096	// RAII object to push / pop sentinel slots for all MS #pragma stacks.
2097	// Actions should be performed only if we enter / exit a C++ method body.
2098	class PragmaStackSentinelRAII {
2099	public:
2100	PragmaStackSentinelRAII(Sema &S, StringRef SlotLabel, bool ShouldAct);
2101	~PragmaStackSentinelRAII();
2102	PragmaStackSentinelRAII(const PragmaStackSentinelRAII &) = delete;
2103	PragmaStackSentinelRAII &
2104	operator=(const PragmaStackSentinelRAII &) = delete;
2105
2106	private:
2107	Sema &S;
2108	StringRef SlotLabel;
2109	bool ShouldAct;
2110	};
2111
2112	/// Last section used with #pragma init_seg.
2113	StringLiteral *CurInitSeg;
2114	SourceLocation CurInitSegLoc;
2115
2116	/// Sections used with #pragma alloc_text.
2117	llvm::StringMap<std::tuple<StringRef, SourceLocation>> FunctionToSectionMap;
2118
2119	/// VisContext - Manages the stack for \#pragma GCC visibility.
2120	void VisContext; // Really a "PragmaVisStack"
2121
2122	/// This an attribute introduced by \#pragma clang attribute.
2123	struct PragmaAttributeEntry {
2124	SourceLocation Loc;
2125	ParsedAttr *Attribute;
2126	SmallVector<attr::SubjectMatchRule, `4`> MatchRules;
2127	bool IsUsed;
2128	};
2129
2130	/// A push'd group of PragmaAttributeEntries.
2131	struct PragmaAttributeGroup {
2132	/// The location of the push attribute.
2133	SourceLocation Loc;
2134	/// The namespace of this push group.
2135	const IdentifierInfo *Namespace;
2136	SmallVector<PragmaAttributeEntry, `2`> Entries;
2137	};
2138
2139	SmallVector<PragmaAttributeGroup, `2`> PragmaAttributeStack;
2140
2141	/// The declaration that is currently receiving an attribute from the
2142	/// #pragma attribute stack.
2143	const Decl *PragmaAttributeCurrentTargetDecl;
2144
2145	/// This represents the last location of a "#pragma clang optimize off"
2146	/// directive if such a directive has not been closed by an "on" yet. If
2147	/// optimizations are currently "on", this is set to an invalid location.
2148	SourceLocation OptimizeOffPragmaLocation;
2149
2150	/// Get the location for the currently active "\#pragma clang optimize
2151	/// off". If this location is invalid, then the state of the pragma is "on".
2152	SourceLocation getOptimizeOffPragmaLocation() const {
2153	return OptimizeOffPragmaLocation;
2154	}
2155
2156	/// The "on" or "off" argument passed by \#pragma optimize, that denotes
2157	/// whether the optimizations in the list passed to the pragma should be
2158	/// turned off or on. This boolean is true by default because command line
2159	/// options are honored when `#pragma optimize("", on)`.
2160	/// (i.e. `ModifyFnAttributeMSPragmaOptimze()` does nothing)
2161	bool MSPragmaOptimizeIsOn = true;
2162
2163	/// Set of no-builtin functions listed by \#pragma function.
2164	llvm::SmallSetVector<StringRef, `4`> MSFunctionNoBuiltins;
2165
2166	/// AddAlignmentAttributesForRecord - Adds any needed alignment attributes to
2167	/// a the record decl, to handle '\#pragma pack' and '\#pragma options align'.
2168	void AddAlignmentAttributesForRecord(RecordDecl *RD);
2169
2170	/// AddMsStructLayoutForRecord - Adds ms_struct layout attribute to record.
2171	void AddMsStructLayoutForRecord(RecordDecl *RD);
2172
2173	/// Add gsl::Pointer attribute to std::container::iterator
2174	/// \param ND The declaration that introduces the name
2175	/// std::container::iterator. \param UnderlyingRecord The record named by ND.
2176	void inferGslPointerAttribute(NamedDecl ND, CXXRecordDecl UnderlyingRecord);
2177
2178	/// Add [[gsl::Owner]] and [[gsl::Pointer]] attributes for std:: types.
2179	void inferGslOwnerPointerAttribute(CXXRecordDecl *Record);
2180
2181	/// Add [[clang:::lifetimebound]] attr for std:: functions and methods.
2182	void inferLifetimeBoundAttribute(FunctionDecl *FD);
2183
2184	/// Add [[clang:::lifetime_capture_by(this)]] to STL container methods.
2185	void inferLifetimeCaptureByAttribute(FunctionDecl *FD);
2186
2187	/// Add [[gsl::Pointer]] attributes for std:: types.
2188	void inferGslPointerAttribute(TypedefNameDecl *TD);
2189
2190	LifetimeCaptureByAttr ParseLifetimeCaptureByAttr(const* ParsedAttr &AL,
2191	StringRef ParamName);
2192	// Processes the argument 'X' in [[clang::lifetime_capture_by(X)]]. Since 'X'
2193	// can be the name of a function parameter, we need to parse the function
2194	// declaration and rest of the parameters before processesing 'X'. Therefore
2195	// do this lazily instead of processing while parsing the annotation itself.
2196	void LazyProcessLifetimeCaptureByParams(FunctionDecl *FD);
2197
2198	/// Add _Nullable attributes for std:: types.
2199	void inferNullableClassAttribute(CXXRecordDecl *CRD);
2200
2201	/// ActOnPragmaClangSection - Called on well formed \#pragma clang section
2202	void ActOnPragmaClangSection(SourceLocation PragmaLoc,
2203	PragmaClangSectionAction Action,
2204	PragmaClangSectionKind SecKind,
2205	StringRef SecName);
2206
2207	/// ActOnPragmaOptionsAlign - Called on well formed \#pragma options align.
2208	void ActOnPragmaOptionsAlign(PragmaOptionsAlignKind Kind,
2209	SourceLocation PragmaLoc);
2210
2211	/// ActOnPragmaPack - Called on well formed \#pragma pack(...).
2212	void ActOnPragmaPack(SourceLocation PragmaLoc, PragmaMsStackAction Action,
2213	StringRef SlotLabel, Expr *Alignment);
2214
2215	/// ConstantFoldAttrArgs - Folds attribute arguments into ConstantExprs
2216	/// (unless they are value dependent or type dependent). Returns false
2217	/// and emits a diagnostic if one or more of the arguments could not be
2218	/// folded into a constant.
2219	bool ConstantFoldAttrArgs(const AttributeCommonInfo &CI,
2220	MutableArrayRef<Expr *> Args);
2221
2222	enum class PragmaAlignPackDiagnoseKind {
2223	NonDefaultStateAtInclude,
2224	ChangedStateAtExit
2225	};
2226
2227	void DiagnoseNonDefaultPragmaAlignPack(PragmaAlignPackDiagnoseKind Kind,
2228	SourceLocation IncludeLoc);
2229	void DiagnoseUnterminatedPragmaAlignPack();
2230
2231	/// ActOnPragmaMSStruct - Called on well formed \#pragma ms_struct [on\|off].
2232	void ActOnPragmaMSStruct(PragmaMSStructKind Kind);
2233
2234	/// ActOnPragmaMSComment - Called on well formed
2235	/// \#pragma comment(kind, "arg").
2236	void ActOnPragmaMSComment(SourceLocation CommentLoc, PragmaMSCommentKind Kind,
2237	StringRef Arg);
2238
2239	/// ActOnPragmaDetectMismatch - Call on well-formed \#pragma detect_mismatch
2240	void ActOnPragmaDetectMismatch(SourceLocation Loc, StringRef Name,
2241	StringRef Value);
2242
2243	/// Are precise floating point semantics currently enabled?
2244	bool isPreciseFPEnabled() {
2245	return !CurFPFeatures.getAllowFPReassociate() &&
2246	!CurFPFeatures.getNoSignedZero() &&
2247	!CurFPFeatures.getAllowReciprocal() &&
2248	!CurFPFeatures.getAllowApproxFunc();
2249	}
2250
2251	void ActOnPragmaFPEvalMethod(SourceLocation Loc,
2252	LangOptions::FPEvalMethodKind Value);
2253
2254	/// ActOnPragmaFloatControl - Call on well-formed \#pragma float_control
2255	void ActOnPragmaFloatControl(SourceLocation Loc, PragmaMsStackAction Action,
2256	PragmaFloatControlKind Value);
2257
2258	/// ActOnPragmaMSPointersToMembers - called on well formed \#pragma
2259	/// pointers_to_members(representation method[, general purpose
2260	/// representation]).
2261	void ActOnPragmaMSPointersToMembers(
2262	LangOptions::PragmaMSPointersToMembersKind Kind,
2263	SourceLocation PragmaLoc);
2264
2265	/// Called on well formed \#pragma vtordisp().
2266	void ActOnPragmaMSVtorDisp(PragmaMsStackAction Action,
2267	SourceLocation PragmaLoc, MSVtorDispMode Value);
2268
2269	bool UnifySection(StringRef SectionName, int SectionFlags,
2270	NamedDecl *TheDecl);
2271	bool UnifySection(StringRef SectionName, int SectionFlags,
2272	SourceLocation PragmaSectionLocation);
2273
2274	/// Called on well formed \#pragma bss_seg/data_seg/const_seg/code_seg.
2275	void ActOnPragmaMSSeg(SourceLocation PragmaLocation,
2276	PragmaMsStackAction Action,
2277	llvm::StringRef StackSlotLabel,
2278	StringLiteral *SegmentName, llvm::StringRef PragmaName);
2279
2280	/// Called on well formed \#pragma section().
2281	void ActOnPragmaMSSection(SourceLocation PragmaLocation, int SectionFlags,
2282	StringLiteral *SegmentName);
2283
2284	/// Called on well-formed \#pragma init_seg().
2285	void ActOnPragmaMSInitSeg(SourceLocation PragmaLocation,
2286	StringLiteral *SegmentName);
2287
2288	/// Called on well-formed \#pragma alloc_text().
2289	void ActOnPragmaMSAllocText(
2290	SourceLocation PragmaLocation, StringRef Section,
2291	const SmallVector<std::tuple<IdentifierInfo *, SourceLocation>>
2292	&Functions);
2293
2294	/// ActOnPragmaMSStrictGuardStackCheck - Called on well formed \#pragma
2295	/// strict_gs_check.
2296	void ActOnPragmaMSStrictGuardStackCheck(SourceLocation PragmaLocation,
2297	PragmaMsStackAction Action,
2298	bool Value);
2299
2300	/// ActOnPragmaUnused - Called on well-formed '\#pragma unused'.
2301	void ActOnPragmaUnused(const Token &Identifier, Scope *curScope,
2302	SourceLocation PragmaLoc);
2303
2304	void ActOnPragmaAttributeAttribute(ParsedAttr &Attribute,
2305	SourceLocation PragmaLoc,
2306	attr::ParsedSubjectMatchRuleSet Rules);
2307	void ActOnPragmaAttributeEmptyPush(SourceLocation PragmaLoc,
2308	const IdentifierInfo *Namespace);
2309
2310	/// Called on well-formed '\#pragma clang attribute pop'.
2311	void ActOnPragmaAttributePop(SourceLocation PragmaLoc,
2312	const IdentifierInfo *Namespace);
2313
2314	/// Adds the attributes that have been specified using the
2315	/// '\#pragma clang attribute push' directives to the given declaration.
2316	void AddPragmaAttributes(Scope S, Decl D);
2317
2318	using InstantiationContextDiagFuncRef =
2319	llvm::function_ref<void(SourceLocation, PartialDiagnostic)>;
2320	auto getDefaultDiagFunc() {
2321	return [this](SourceLocation Loc, PartialDiagnostic PD) {
2322	// This bypasses a lot of the filters in the diag engine, as it's
2323	// to be used to attach notes to diagnostics which have already
2324	// been filtered through.
2325	DiagnosticBuilder Builder(Diags.Report(Loc, DiagID: PD.getDiagID()));
2326	PD.Emit(DB: Builder);
2327	};
2328	}
2329
2330	void PrintPragmaAttributeInstantiationPoint(
2331	InstantiationContextDiagFuncRef DiagFunc);
2332	void PrintPragmaAttributeInstantiationPoint() {
2333	PrintPragmaAttributeInstantiationPoint(DiagFunc: getDefaultDiagFunc());
2334	}
2335
2336	void DiagnoseUnterminatedPragmaAttribute();
2337
2338	/// Called on well formed \#pragma clang optimize.
2339	void ActOnPragmaOptimize(bool On, SourceLocation PragmaLoc);
2340
2341	/// #pragma optimize("[optimization-list]", on \| off).
2342	void ActOnPragmaMSOptimize(SourceLocation Loc, bool IsOn);
2343
2344	/// Call on well formed \#pragma function.
2345	void
2346	ActOnPragmaMSFunction(SourceLocation Loc,
2347	const llvm::SmallVectorImpl<StringRef> &NoBuiltins);
2348
2349	NamedDecl lookupExternCFunctionOrVariable(IdentifierInfo IdentId,
2350	SourceLocation NameLoc,
2351	Scope *curScope);
2352
2353	/// Information from a C++ #pragma export, for a symbol that we
2354	/// haven't seen the declaration for yet.
2355	struct PendingPragmaInfo {
2356	SourceLocation NameLoc;
2357	bool Used;
2358	};
2359
2360	llvm::DenseMap<IdentifierInfo *, PendingPragmaInfo> PendingExportedNames;
2361
2362	/// ActonPragmaExport - called on well-formed '\#pragma export'.
2363	void ActOnPragmaExport(IdentifierInfo *IdentId, SourceLocation ExportNameLoc,
2364	Scope *curScope);
2365
2366	/// Only called on function definitions; if there is a pragma in scope
2367	/// with the effect of a range-based optnone, consider marking the function
2368	/// with attribute optnone.
2369	void AddRangeBasedOptnone(FunctionDecl *FD);
2370
2371	/// Only called on function definitions; if there is a `#pragma alloc_text`
2372	/// that decides which code section the function should be in, add
2373	/// attribute section to the function.
2374	void AddSectionMSAllocText(FunctionDecl *FD);
2375
2376	/// Adds the 'optnone' attribute to the function declaration if there
2377	/// are no conflicts; Loc represents the location causing the 'optnone'
2378	/// attribute to be added (usually because of a pragma).
2379	void AddOptnoneAttributeIfNoConflicts(FunctionDecl *FD, SourceLocation Loc);
2380
2381	/// Only called on function definitions; if there is a MSVC #pragma optimize
2382	/// in scope, consider changing the function's attributes based on the
2383	/// optimization list passed to the pragma.
2384	void ModifyFnAttributesMSPragmaOptimize(FunctionDecl *FD);
2385
2386	/// Only called on function definitions; if there is a pragma in scope
2387	/// with the effect of a range-based no_builtin, consider marking the function
2388	/// with attribute no_builtin.
2389	void AddImplicitMSFunctionNoBuiltinAttr(FunctionDecl *FD);
2390
2391	/// AddPushedVisibilityAttribute - If '\#pragma GCC visibility' was used,
2392	/// add an appropriate visibility attribute.
2393	void AddPushedVisibilityAttribute(Decl *RD);
2394
2395	/// FreeVisContext - Deallocate and null out VisContext.
2396	void FreeVisContext();
2397
2398	/// ActOnPragmaVisibility - Called on well formed \#pragma GCC visibility... .
2399	void ActOnPragmaVisibility(const IdentifierInfo *VisType,
2400	SourceLocation PragmaLoc);
2401
2402	/// ActOnPragmaFPContract - Called on well formed
2403	/// \#pragma {STDC,OPENCL} FP_CONTRACT and
2404	/// \#pragma clang fp contract
2405	void ActOnPragmaFPContract(SourceLocation Loc, LangOptions::FPModeKind FPC);
2406
2407	/// Called on well formed
2408	/// \#pragma clang fp reassociate
2409	/// or
2410	/// \#pragma clang fp reciprocal
2411	void ActOnPragmaFPValueChangingOption(SourceLocation Loc, PragmaFPKind Kind,
2412	bool IsEnabled);
2413
2414	/// ActOnPragmaFenvAccess - Called on well formed
2415	/// \#pragma STDC FENV_ACCESS
2416	void ActOnPragmaFEnvAccess(SourceLocation Loc, bool IsEnabled);
2417
2418	/// ActOnPragmaCXLimitedRange - Called on well formed
2419	/// \#pragma STDC CX_LIMITED_RANGE
2420	void ActOnPragmaCXLimitedRange(SourceLocation Loc,
2421	LangOptions::ComplexRangeKind Range);
2422
2423	/// Called on well formed '\#pragma clang fp' that has option 'exceptions'.
2424	void ActOnPragmaFPExceptions(SourceLocation Loc,
2425	LangOptions::FPExceptionModeKind);
2426
2427	/// Called to set constant rounding mode for floating point operations.
2428	void ActOnPragmaFEnvRound(SourceLocation Loc, llvm::RoundingMode);
2429
2430	/// Called to set exception behavior for floating point operations.
2431	void setExceptionMode(SourceLocation Loc, LangOptions::FPExceptionModeKind);
2432
2433	/// PushNamespaceVisibilityAttr - Note that we've entered a
2434	/// namespace with a visibility attribute.
2435	void PushNamespaceVisibilityAttr(const VisibilityAttr *Attr,
2436	SourceLocation Loc);
2437
2438	/// PopPragmaVisibility - Pop the top element of the visibility stack; used
2439	/// for '\#pragma GCC visibility' and visibility attributes on namespaces.
2440	void PopPragmaVisibility(bool IsNamespaceEnd, SourceLocation EndLoc);
2441
2442	/// Handles semantic checking for features that are common to all attributes,
2443	/// such as checking whether a parameter was properly specified, or the
2444	/// correct number of arguments were passed, etc. Returns true if the
2445	/// attribute has been diagnosed.
2446	bool checkCommonAttributeFeatures(const Decl D, const* ParsedAttr &A,
2447	bool SkipArgCountCheck = false);
2448	bool checkCommonAttributeFeatures(const Stmt S, const* ParsedAttr &A,
2449	bool SkipArgCountCheck = false);
2450
2451	///@}
2452
2453	//
2454	//
2455	// -------------------------------------------------------------------------
2456	//
2457	//
2458
2459	/// \name Availability Attribute Handling
2460	/// Implementations are in SemaAvailability.cpp
2461	///@{
2462
2463	public:
2464	/// Issue any -Wunguarded-availability warnings in \c FD
2465	void DiagnoseUnguardedAvailabilityViolations(Decl *FD);
2466
2467	void handleDelayedAvailabilityCheck(sema::DelayedDiagnostic &DD, Decl *Ctx);
2468
2469	/// Retrieve the current function, if any, that should be analyzed for
2470	/// potential availability violations.
2471	sema::FunctionScopeInfo *getCurFunctionAvailabilityContext();
2472
2473	void DiagnoseAvailabilityOfDecl(NamedDecl *D, ArrayRef<SourceLocation> Locs,
2474	const ObjCInterfaceDecl *UnknownObjCClass,
2475	bool ObjCPropertyAccess,
2476	bool AvoidPartialAvailabilityChecks,
2477	ObjCInterfaceDecl *ClassReceiver);
2478
2479	void DiagnoseAvailabilityOfDecl(NamedDecl *D, ArrayRef<SourceLocation> Locs);
2480
2481	std::pair<AvailabilityResult, const NamedDecl *>
2482	ShouldDiagnoseAvailabilityOfDecl(const NamedDecl D, std::string Message,
2483	ObjCInterfaceDecl *ClassReceiver);
2484	///@}
2485
2486	//
2487	//
2488	// -------------------------------------------------------------------------
2489	//
2490	//
2491
2492	/// \name Bounds Safety
2493	/// Implementations are in SemaBoundsSafety.cpp
2494	///@{
2495	public:
2496	/// Check if applying the specified attribute variant from the "counted by"
2497	/// family of attributes to FieldDecl \p FD is semantically valid. If
2498	/// semantically invalid diagnostics will be emitted explaining the problems.
2499	///
2500	/// \param FD The FieldDecl to apply the attribute to
2501	/// \param E The count expression on the attribute
2502	/// \param CountInBytes If true the attribute is from the "sized_by" family of
2503	/// attributes. If the false the attribute is from
2504	/// "counted_by" family of attributes.
2505	/// \param OrNull If true the attribute is from the "_or_null" suffixed family
2506	/// of attributes. If false the attribute does not have the
2507	/// suffix.
2508	///
2509	/// Together \p CountInBytes and \p OrNull decide the attribute variant. E.g.
2510	/// \p CountInBytes and \p OrNull both being true indicates the
2511	/// `counted_by_or_null` attribute.
2512	///
2513	/// \returns false iff semantically valid.
2514	bool CheckCountedByAttrOnField(FieldDecl FD, Expr E, bool CountInBytes,
2515	bool OrNull);
2516
2517	/// Perform Bounds Safety Semantic checks for assigning to a `__counted_by` or
2518	/// `__counted_by_or_null` pointer type \param LHSTy.
2519	///
2520	/// \param LHSTy The type being assigned to. Checks will only be performed if
2521	/// the type is a `counted_by` or `counted_by_or_null ` pointer.
2522	/// \param RHSExpr The expression being assigned from.
2523	/// \param Action The type assignment being performed
2524	/// \param Loc The SourceLocation to use for error diagnostics
2525	/// \param Assignee The ValueDecl being assigned. This is used to compute
2526	/// the name of the assignee. If the assignee isn't known this can
2527	/// be set to nullptr.
2528	/// \param ShowFullyQualifiedAssigneeName If set to true when using \p
2529	/// Assignee to compute the name of the assignee use the fully
2530	/// qualified name, otherwise use the unqualified name.
2531	///
2532	/// \returns True iff no diagnostic where emitted, false otherwise.
2533	bool BoundsSafetyCheckAssignmentToCountAttrPtr(
2534	QualType LHSTy, Expr *RHSExpr, AssignmentAction Action,
2535	SourceLocation Loc, const ValueDecl *Assignee,
2536	bool ShowFullyQualifiedAssigneeName);
2537
2538	/// Perform Bounds Safety Semantic checks for initializing a Bounds Safety
2539	/// pointer.
2540	///
2541	/// \param Entity The entity being initialized
2542	/// \param Kind The kind of initialization being performed
2543	/// \param Action The type assignment being performed
2544	/// \param LHSTy The type being assigned to. Checks will only be performed if
2545	/// the type is a `counted_by` or `counted_by_or_null ` pointer.
2546	/// \param RHSExpr The expression being used for initialization.
2547	///
2548	/// \returns True iff no diagnostic where emitted, false otherwise.
2549	bool BoundsSafetyCheckInitialization(const InitializedEntity &Entity,
2550	const InitializationKind &Kind,
2551	AssignmentAction Action,
2552	QualType LHSType, Expr *RHSExpr);
2553
2554	/// Perform Bounds Safety semantic checks for uses of invalid uses counted_by
2555	/// or counted_by_or_null pointers in \param E.
2556	///
2557	/// \param E the expression to check
2558	///
2559	/// \returns True iff no diagnostic where emitted, false otherwise.
2560	bool BoundsSafetyCheckUseOfCountAttrPtr(const Expr *E);
2561	///@}
2562
2563	//
2564	//
2565	// -------------------------------------------------------------------------
2566	//
2567	//
2568
2569	/// \name Casts
2570	/// Implementations are in SemaCast.cpp
2571	///@{
2572
2573	public:
2574	static bool isCast(CheckedConversionKind CCK) {
2575	return CCK == CheckedConversionKind::CStyleCast \|\|
2576	CCK == CheckedConversionKind::FunctionalCast \|\|
2577	CCK == CheckedConversionKind::OtherCast;
2578	}
2579
2580	/// ActOnCXXNamedCast - Parse
2581	/// {dynamic,static,reinterpret,const,addrspace}_cast's.
2582	ExprResult ActOnCXXNamedCast(SourceLocation OpLoc, tok::TokenKind Kind,
2583	SourceLocation LAngleBracketLoc, Declarator &D,
2584	SourceLocation RAngleBracketLoc,
2585	SourceLocation LParenLoc, Expr *E,
2586	SourceLocation RParenLoc);
2587
2588	ExprResult BuildCXXNamedCast(SourceLocation OpLoc, tok::TokenKind Kind,
2589	TypeSourceInfo Ty, Expr E,
2590	SourceRange AngleBrackets, SourceRange Parens);
2591
2592	ExprResult ActOnBuiltinBitCastExpr(SourceLocation KWLoc, Declarator &Dcl,
2593	ExprResult Operand,
2594	SourceLocation RParenLoc);
2595
2596	ExprResult BuildBuiltinBitCastExpr(SourceLocation KWLoc, TypeSourceInfo *TSI,
2597	Expr *Operand, SourceLocation RParenLoc);
2598
2599	// Checks that reinterpret casts don't have undefined behavior.
2600	void CheckCompatibleReinterpretCast(QualType SrcType, QualType DestType,
2601	bool IsDereference, SourceRange Range);
2602
2603	// Checks that the vector type should be initialized from a scalar
2604	// by splatting the value rather than populating a single element.
2605	// This is the case for AltiVecVector types as well as with
2606	// AltiVecPixel and AltiVecBool when -faltivec-src-compat=xl is specified.
2607	bool ShouldSplatAltivecScalarInCast(const VectorType *VecTy);
2608
2609	// Checks if the -faltivec-src-compat=gcc option is specified.
2610	// If so, AltiVecVector, AltiVecBool and AltiVecPixel types are
2611	// treated the same way as they are when trying to initialize
2612	// these vectors on gcc (an error is emitted).
2613	bool CheckAltivecInitFromScalar(SourceRange R, QualType VecTy,
2614	QualType SrcTy);
2615
2616	ExprResult BuildCStyleCastExpr(SourceLocation LParenLoc, TypeSourceInfo *Ty,
2617	SourceLocation RParenLoc, Expr *Op);
2618
2619	ExprResult BuildCXXFunctionalCastExpr(TypeSourceInfo *TInfo, QualType Type,
2620	SourceLocation LParenLoc,
2621	Expr *CastExpr,
2622	SourceLocation RParenLoc);
2623
2624	///@}
2625
2626	//
2627	//
2628	// -------------------------------------------------------------------------
2629	//
2630	//
2631
2632	/// \name Extra Semantic Checking
2633	/// Implementations are in SemaChecking.cpp
2634	///@{
2635
2636	public:
2637	/// Used to change context to isConstantEvaluated without pushing a heavy
2638	/// ExpressionEvaluationContextRecord object.
2639	bool isConstantEvaluatedOverride = false;
2640
2641	bool isConstantEvaluatedContext() const {
2642	return currentEvaluationContext().isConstantEvaluated() \|\|
2643	isConstantEvaluatedOverride;
2644	}
2645
2646	SourceLocation getLocationOfStringLiteralByte(const StringLiteral *SL,
2647	unsigned ByteNo) const;
2648
2649	enum FormatArgumentPassingKind {
2650	FAPK_Fixed, // values to format are fixed (no C-style variadic arguments)
2651	FAPK_Variadic, // values to format are passed as variadic arguments
2652	FAPK_VAList, // values to format are passed in a va_list
2653	FAPK_Elsewhere, // values to format are not passed to this function
2654	};
2655
2656	// Used to grab the relevant information from a FormatAttr and a
2657	// FunctionDeclaration.
2658	struct FormatStringInfo {
2659	unsigned FormatIdx;
2660	unsigned FirstDataArg;
2661	FormatArgumentPassingKind ArgPassingKind;
2662	};
2663
2664	/// Given a function and its FormatAttr or FormatMatchesAttr info, attempts to
2665	/// populate the FormatStringInfo parameter with the attribute's correct
2666	/// format_idx and firstDataArg. Returns true when the format fits the
2667	/// function and the FormatStringInfo has been populated.
2668	static bool getFormatStringInfo(const Decl Function, unsigned* FormatIdx,
2669	unsigned FirstArg, FormatStringInfo *FSI);
2670	static bool getFormatStringInfo(unsigned FormatIdx, unsigned FirstArg,
2671	bool HasImplicitThisParam, bool IsVariadic,
2672	FormatStringInfo *FSI);
2673
2674	// Used by C++ template instantiation.
2675	ExprResult BuiltinShuffleVector(CallExpr *TheCall);
2676
2677	/// ConvertVectorExpr - Handle __builtin_convertvector
2678	ExprResult ConvertVectorExpr(Expr E, TypeSourceInfo TInfo,
2679	SourceLocation BuiltinLoc,
2680	SourceLocation RParenLoc);
2681
2682	static StringRef GetFormatStringTypeName(FormatStringType FST);
2683	static FormatStringType GetFormatStringType(StringRef FormatFlavor);
2684	static FormatStringType GetFormatStringType(const FormatAttr *Format);
2685	static FormatStringType GetFormatStringType(const FormatMatchesAttr *Format);
2686
2687	bool FormatStringHasSArg(const StringLiteral *FExpr);
2688
2689	/// Check for comparisons of floating-point values using == and !=. Issue a
2690	/// warning if the comparison is not likely to do what the programmer
2691	/// intended.
2692	void CheckFloatComparison(SourceLocation Loc, const Expr *LHS,
2693	const Expr *RHS, BinaryOperatorKind Opcode);
2694
2695	/// Register a magic integral constant to be used as a type tag.
2696	void RegisterTypeTagForDatatype(const IdentifierInfo *ArgumentKind,
2697	uint64_t MagicValue, QualType Type,
2698	bool LayoutCompatible, bool MustBeNull);
2699
2700	struct TypeTagData {
2701	TypeTagData() {}
2702
2703	TypeTagData(QualType Type, bool LayoutCompatible, bool MustBeNull)
2704	: Type (Type), LayoutCompatible(LayoutCompatible),
2705	MustBeNull(MustBeNull) {}
2706
2707	QualType Type;
2708
2709	/// If true, \c Type should be compared with other expression's types for
2710	/// layout-compatibility.
2711	LLVM_PREFERRED_TYPE(bool)
2712	unsigned LayoutCompatible : `1`;
2713	LLVM_PREFERRED_TYPE(bool)
2714	unsigned MustBeNull : `1`;
2715	};
2716
2717	/// A pair of ArgumentKind identifier and magic value. This uniquely
2718	/// identifies the magic value.
2719	typedef std::pair<const IdentifierInfo *, uint64_t> TypeTagMagicValue;
2720
2721	/// Diagnoses the current set of gathered accesses. This happens at the end of
2722	/// each expression evaluation context. Diagnostics are emitted only for
2723	/// accesses gathered in the current evaluation context.
2724	void DiagnoseMisalignedMembers();
2725
2726	/// This function checks if the expression is in the sef of potentially
2727	/// misaligned members and it is converted to some pointer type T with lower
2728	/// or equal alignment requirements. If so it removes it. This is used when
2729	/// we do not want to diagnose such misaligned access (e.g. in conversions to
2730	/// void).*
2731	void DiscardMisalignedMemberAddress(const Type T, Expr E);
2732
2733	/// Returns true if `From` is a function or pointer to a function with the
2734	/// `cfi_unchecked_callee` attribute but `To` is a function or pointer to
2735	/// function without this attribute.
2736	bool DiscardingCFIUncheckedCallee(QualType From, QualType To) const;
2737
2738	/// This function calls Action when it determines that E designates a
2739	/// misaligned member due to the packed attribute. This is used to emit
2740	/// local diagnostics like in reference binding.
2741	void RefersToMemberWithReducedAlignment(
2742	Expr *E,
2743	llvm::function_ref<void(Expr , RecordDecl , FieldDecl *, CharUnits)>
2744	Action);
2745
2746	enum class AtomicArgumentOrder { API, AST };
2747	ExprResult
2748	BuildAtomicExpr(SourceRange CallRange, SourceRange ExprRange,
2749	SourceLocation RParenLoc, MultiExprArg Args,
2750	AtomicExpr::AtomicOp Op,
2751	AtomicArgumentOrder ArgOrder = AtomicArgumentOrder::API);
2752
2753	/// Check to see if a given expression could have '.c_str()' called on it.
2754	bool hasCStrMethod(const Expr *E);
2755
2756	/// Diagnose pointers that are always non-null.
2757	/// \param E the expression containing the pointer
2758	/// \param NullKind NPCK_NotNull if E is a cast to bool, otherwise, E is
2759	/// compared to a null pointer
2760	/// \param IsEqual True when the comparison is equal to a null pointer
2761	/// \param Range Extra SourceRange to highlight in the diagnostic
2762	void DiagnoseAlwaysNonNullPointer(Expr *E,
2763	Expr::NullPointerConstantKind NullType,
2764	bool IsEqual, SourceRange Range);
2765
2766	/// CheckParmsForFunctionDef - Check that the parameters of the given
2767	/// function are appropriate for the definition of a function. This
2768	/// takes care of any checks that cannot be performed on the
2769	/// declaration itself, e.g., that the types of each of the function
2770	/// parameters are complete.
2771	bool CheckParmsForFunctionDef(ArrayRef<ParmVarDecl *> Parameters,
2772	bool CheckParameterNames);
2773
2774	/// CheckCastAlign - Implements -Wcast-align, which warns when a
2775	/// pointer cast increases the alignment requirements.
2776	void CheckCastAlign(Expr *Op, QualType T, SourceRange TRange);
2777
2778	/// checkUnsafeAssigns - Check whether +1 expr is being assigned
2779	/// to weak/__unsafe_unretained type.
2780	bool checkUnsafeAssigns(SourceLocation Loc, QualType LHS, Expr *RHS);
2781
2782	/// checkUnsafeExprAssigns - Check whether +1 expr is being assigned
2783	/// to weak/__unsafe_unretained expression.
2784	void checkUnsafeExprAssigns(SourceLocation Loc, Expr LHS, Expr RHS);
2785
2786	/// Emit \p DiagID if statement located on \p StmtLoc has a suspicious null
2787	/// statement as a \p Body, and it is located on the same line.
2788	///
2789	/// This helps prevent bugs due to typos, such as:
2790	/// if (condition);
2791	/// do_stuff();
2792	void DiagnoseEmptyStmtBody(SourceLocation StmtLoc, const Stmt *Body,
2793	unsigned DiagID);
2794
2795	/// Warn if a for/while loop statement \p S, which is followed by
2796	/// \p PossibleBody, has a suspicious null statement as a body.
2797	void DiagnoseEmptyLoopBody(const Stmt S, const* Stmt *PossibleBody);
2798
2799	/// DiagnoseSelfMove - Emits a warning if a value is moved to itself.
2800	void DiagnoseSelfMove(const Expr LHSExpr, const* Expr *RHSExpr,
2801	SourceLocation OpLoc);
2802
2803	bool IsLayoutCompatible(QualType T1, QualType T2) const;
2804	bool IsPointerInterconvertibleBaseOf(const TypeSourceInfo *Base,
2805	const TypeSourceInfo *Derived);
2806
2807	/// CheckFunctionCall - Check a direct function call for various correctness
2808	/// and safety properties not strictly enforced by the C type system.
2809	bool CheckFunctionCall(FunctionDecl FDecl, CallExpr TheCall,
2810	const FunctionProtoType *Proto);
2811
2812	enum class EltwiseBuiltinArgTyRestriction {
2813	None,
2814	FloatTy,
2815	IntegerTy,
2816	SignedIntOrFloatTy,
2817	};
2818
2819	/// \param FPOnly restricts the arguments to floating-point types.
2820	std::optional<QualType>
2821	BuiltinVectorMath(CallExpr *TheCall,
2822	EltwiseBuiltinArgTyRestriction ArgTyRestr =
2823	EltwiseBuiltinArgTyRestriction::None);
2824	bool BuiltinVectorToScalarMath(CallExpr *TheCall);
2825
2826	void checkLifetimeCaptureBy(FunctionDecl FDecl, bool* IsMemberFunction,
2827	const Expr ThisArg, ArrayRef<const* Expr *> Args);
2828
2829	/// Handles the checks for format strings, non-POD arguments to vararg
2830	/// functions, NULL arguments passed to non-NULL parameters, diagnose_if
2831	/// attributes and AArch64 SME attributes.
2832	void checkCall(NamedDecl FDecl, const* FunctionProtoType *Proto,
2833	const Expr ThisArg, ArrayRef<const* Expr *> Args,
2834	bool IsMemberFunction, SourceLocation Loc, SourceRange Range,
2835	VariadicCallType CallType);
2836
2837	/// Verify that two format strings (as understood by attribute(format) and
2838	/// attribute(format_matches) are compatible. If they are incompatible,
2839	/// diagnostics are emitted with the assumption that \c
2840	/// AuthoritativeFormatString is correct and
2841	/// \c TestedFormatString is wrong. If \c FunctionCallArg is provided,
2842	/// diagnostics will point to it and a note will refer to \c
2843	/// TestedFormatString or \c AuthoritativeFormatString as appropriate.
2844	bool
2845	CheckFormatStringsCompatible(FormatStringType FST,
2846	const StringLiteral *AuthoritativeFormatString,
2847	const StringLiteral *TestedFormatString,
2848	const Expr FunctionCallArg = nullptr*);
2849
2850	/// Verify that one format string (as understood by attribute(format)) is
2851	/// self-consistent; for instance, that it doesn't have multiple positional
2852	/// arguments referring to the same argument in incompatible ways. Diagnose
2853	/// if it isn't.
2854	bool ValidateFormatString(FormatStringType FST, const StringLiteral *Str);
2855
2856	/// \brief Enforce the bounds of a TCB
2857	/// CheckTCBEnforcement - Enforces that every function in a named TCB only
2858	/// directly calls other functions in the same TCB as marked by the
2859	/// enforce_tcb and enforce_tcb_leaf attributes.
2860	void CheckTCBEnforcement(const SourceLocation CallExprLoc,
2861	const NamedDecl *Callee);
2862
2863	void CheckConstrainedAuto(const AutoType *AutoT, SourceLocation Loc);
2864
2865	/// BuiltinConstantArg - Handle a check if argument ArgNum of CallExpr
2866	/// TheCall is a constant expression.
2867	bool BuiltinConstantArg(CallExpr TheCall, unsigned* ArgNum,
2868	llvm::APSInt &Result);
2869
2870	/// BuiltinConstantArgRange - Handle a check if argument ArgNum of CallExpr
2871	/// TheCall is a constant expression in the range [Low, High].
2872	bool BuiltinConstantArgRange(CallExpr TheCall, unsigned* ArgNum, int Low,
2873	int High, bool RangeIsError = true);
2874
2875	/// BuiltinConstantArgMultiple - Handle a check if argument ArgNum of CallExpr
2876	/// TheCall is a constant expression is a multiple of Num..
2877	bool BuiltinConstantArgMultiple(CallExpr TheCall, unsigned* ArgNum,
2878	unsigned Multiple);
2879
2880	/// BuiltinConstantArgPower2 - Check if argument ArgNum of TheCall is a
2881	/// constant expression representing a power of 2.
2882	bool BuiltinConstantArgPower2(CallExpr TheCall, unsigned* ArgNum);
2883
2884	/// BuiltinConstantArgShiftedByte - Check if argument ArgNum of TheCall is
2885	/// a constant expression representing an arbitrary byte value shifted left by
2886	/// a multiple of 8 bits.
2887	bool BuiltinConstantArgShiftedByte(CallExpr TheCall, unsigned* ArgNum,
2888	unsigned ArgBits);
2889
2890	/// BuiltinConstantArgShiftedByteOr0xFF - Check if argument ArgNum of
2891	/// TheCall is a constant expression representing either a shifted byte value,
2892	/// or a value of the form 0x??FF (i.e. a member of the arithmetic progression
2893	/// 0x00FF, 0x01FF, ..., 0xFFFF). This strange range check is needed for some
2894	/// Arm MVE intrinsics.
2895	bool BuiltinConstantArgShiftedByteOrXXFF(CallExpr TheCall, unsigned* ArgNum,
2896	unsigned ArgBits);
2897
2898	/// Checks that a call expression's argument count is at least the desired
2899	/// number. This is useful when doing custom type-checking on a variadic
2900	/// function. Returns true on error.
2901	bool checkArgCountAtLeast(CallExpr Call, unsigned* MinArgCount);
2902
2903	/// Checks that a call expression's argument count is at most the desired
2904	/// number. This is useful when doing custom type-checking on a variadic
2905	/// function. Returns true on error.
2906	bool checkArgCountAtMost(CallExpr Call, unsigned* MaxArgCount);
2907
2908	/// Checks that a call expression's argument count is in the desired range.
2909	/// This is useful when doing custom type-checking on a variadic function.
2910	/// Returns true on error.
2911	bool checkArgCountRange(CallExpr Call, unsigned* MinArgCount,
2912	unsigned MaxArgCount);
2913
2914	/// Checks that a call expression's argument count is the desired number.
2915	/// This is useful when doing custom type-checking. Returns true on error.
2916	bool checkArgCount(CallExpr Call, unsigned* DesiredArgCount);
2917
2918	/// Returns true if the argument consists of one contiguous run of 1s with any
2919	/// number of 0s on either side. The 1s are allowed to wrap from LSB to MSB,
2920	/// so 0x000FFF0, 0x0000FFFF, 0xFF0000FF, 0x0 are all runs. 0x0F0F0000 is not,
2921	/// since all 1s are not contiguous.
2922	bool ValueIsRunOfOnes(CallExpr TheCall, unsigned* ArgNum);
2923
2924	void CheckImplicitConversion(Expr *E, QualType T, SourceLocation CC,
2925	bool ICContext = nullptr*,
2926	bool IsListInit = false);
2927
2928	/// Check for overflow behavior type related implicit conversion diagnostics.
2929	/// Returns true if OBT-related diagnostic was issued, false otherwise.
2930	bool CheckOverflowBehaviorTypeConversion(Expr *E, QualType T,
2931	SourceLocation CC);
2932
2933	bool
2934	BuiltinElementwiseTernaryMath(CallExpr *TheCall,
2935	EltwiseBuiltinArgTyRestriction ArgTyRestr =
2936	EltwiseBuiltinArgTyRestriction::FloatTy);
2937	bool PrepareBuiltinElementwiseMathOneArgCall(
2938	CallExpr *TheCall, EltwiseBuiltinArgTyRestriction ArgTyRestr =
2939	EltwiseBuiltinArgTyRestriction::None);
2940
2941	private:
2942	void CheckArrayAccess(const Expr BaseExpr, const* Expr *IndexExpr,
2943	const ArraySubscriptExpr ASE = nullptr*,
2944	bool AllowOnePastEnd = true, bool IndexNegated = false);
2945	void CheckArrayAccess(const Expr *E);
2946
2947	bool CheckPointerCall(NamedDecl NDecl, CallExpr TheCall,
2948	const FunctionProtoType *Proto);
2949
2950	/// Checks function calls when a FunctionDecl or a NamedDecl is not available,
2951	/// such as function pointers returned from functions.
2952	bool CheckOtherCall(CallExpr TheCall, const* FunctionProtoType *Proto);
2953
2954	/// CheckConstructorCall - Check a constructor call for correctness and safety
2955	/// properties not enforced by the C type system.
2956	void CheckConstructorCall(FunctionDecl *FDecl, QualType ThisType,
2957	ArrayRef<const Expr *> Args,
2958	const FunctionProtoType *Proto, SourceLocation Loc);
2959
2960	/// Warn if a pointer or reference argument passed to a function points to an
2961	/// object that is less aligned than the parameter. This can happen when
2962	/// creating a typedef with a lower alignment than the original type and then
2963	/// calling functions defined in terms of the original type.
2964	void CheckArgAlignment(SourceLocation Loc, NamedDecl *FDecl,
2965	StringRef ParamName, QualType ArgTy, QualType ParamTy);
2966
2967	ExprResult CheckOSLogFormatStringArg(Expr *Arg);
2968
2969	ExprResult CheckBuiltinFunctionCall(FunctionDecl FDecl, unsigned* BuiltinID,
2970	CallExpr *TheCall);
2971
2972	bool CheckTSBuiltinFunctionCall(const TargetInfo &TI, unsigned BuiltinID,
2973	CallExpr *TheCall);
2974
2975	void checkFortifiedBuiltinMemoryFunction(FunctionDecl FD, CallExpr TheCall);
2976
2977	/// Argument-value fortify checks for libc functions that are not builtins,
2978	/// dispatched by name (e.g. umask). Diagnostics belong to -Wfortify-source.
2979	void checkFortifiedLibcArgument(FunctionDecl FD, CallExpr TheCall);
2980
2981	/// Check the arguments to '__builtin_va_start', '__builtin_ms_va_start',
2982	/// or '__builtin_c23_va_start' for validity. Emit an error and return true
2983	/// on failure; return false on success.
2984	bool BuiltinVAStart(unsigned BuiltinID, CallExpr *TheCall);
2985	bool BuiltinVAStartARMMicrosoft(CallExpr *Call);
2986
2987	/// BuiltinUnorderedCompare - Handle functions like __builtin_isgreater and
2988	/// friends. This is declared to take (...), so we have to check everything.
2989	bool BuiltinUnorderedCompare(CallExpr TheCall, unsigned* BuiltinID);
2990
2991	/// BuiltinSemaBuiltinFPClassification - Handle functions like
2992	/// __builtin_isnan and friends. This is declared to take (...), so we have
2993	/// to check everything.
2994	bool BuiltinFPClassification(CallExpr TheCall, unsigned* NumArgs,
2995	unsigned BuiltinID);
2996
2997	/// Perform semantic analysis for a call to __builtin_complex.
2998	bool BuiltinComplex(CallExpr *TheCall);
2999	bool BuiltinOSLogFormat(CallExpr *TheCall);
3000
3001	/// BuiltinPrefetch - Handle __builtin_prefetch.
3002	/// This is declared to take (const void, ...) and can take two*
3003	/// optional constant int args.
3004	bool BuiltinPrefetch(CallExpr *TheCall);
3005
3006	/// Handle __builtin_alloca_with_align. This is declared
3007	/// as (size_t, size_t) where the second size_t must be a power of 2 greater
3008	/// than 8.
3009	bool BuiltinAllocaWithAlign(CallExpr *TheCall);
3010
3011	/// BuiltinArithmeticFence - Handle __arithmetic_fence.
3012	bool BuiltinArithmeticFence(CallExpr *TheCall);
3013
3014	/// BuiltinAssume - Handle __assume (MS Extension).
3015	/// __assume does not evaluate its arguments, and should warn if its argument
3016	/// has side effects.
3017	bool BuiltinAssume(CallExpr *TheCall);
3018
3019	/// Handle __builtin_assume_aligned. This is declared
3020	/// as (const void, size_t, ...) and can take one optional constant int arg.*
3021	bool BuiltinAssumeAligned(CallExpr *TheCall);
3022
3023	/// BuiltinLongjmp - Handle __builtin_longjmp(void env[5], int val).*
3024	/// This checks that the target supports __builtin_longjmp and
3025	/// that val is a constant 1.
3026	bool BuiltinLongjmp(CallExpr *TheCall);
3027
3028	/// BuiltinSetjmp - Handle __builtin_setjmp(void env[5]).*
3029	/// This checks that the target supports __builtin_setjmp.
3030	bool BuiltinSetjmp(CallExpr *TheCall);
3031
3032	/// We have a call to a function like __sync_fetch_and_add, which is an
3033	/// overloaded function based on the pointer type of its first argument.
3034	/// The main BuildCallExpr routines have already promoted the types of
3035	/// arguments because all of these calls are prototyped as void(...).
3036	///
3037	/// This function goes through and does final semantic checking for these
3038	/// builtins, as well as generating any warnings.
3039	ExprResult BuiltinAtomicOverloaded(ExprResult TheCallResult);
3040
3041	/// BuiltinNontemporalOverloaded - We have a call to
3042	/// __builtin_nontemporal_store or __builtin_nontemporal_load, which is an
3043	/// overloaded function based on the pointer type of its last argument.
3044	///
3045	/// This function goes through and does final semantic checking for these
3046	/// builtins.
3047	ExprResult BuiltinNontemporalOverloaded(ExprResult TheCallResult);
3048	ExprResult AtomicOpsOverloaded(ExprResult TheCallResult,
3049	AtomicExpr::AtomicOp Op);
3050
3051	/// \param FPOnly restricts the arguments to floating-point types.
3052	bool BuiltinElementwiseMath(CallExpr *TheCall,
3053	EltwiseBuiltinArgTyRestriction ArgTyRestr =
3054	EltwiseBuiltinArgTyRestriction::None);
3055	bool PrepareBuiltinReduceMathOneArgCall(CallExpr *TheCall);
3056
3057	bool BuiltinNonDeterministicValue(CallExpr *TheCall);
3058
3059	bool CheckInvalidBuiltinCountedByRef(const Expr *E,
3060	BuiltinCountedByRefKind K);
3061	bool BuiltinCountedByRef(CallExpr *TheCall);
3062
3063	// Matrix builtin handling.
3064	ExprResult BuiltinMatrixTranspose(CallExpr *TheCall, ExprResult CallResult);
3065	ExprResult BuiltinMatrixColumnMajorLoad(CallExpr *TheCall,
3066	ExprResult CallResult);
3067	ExprResult BuiltinMatrixColumnMajorStore(CallExpr *TheCall,
3068	ExprResult CallResult);
3069
3070	/// CheckFormatArguments - Check calls to printf and scanf (and similar
3071	/// functions) for correct use of format strings.
3072	/// Returns true if a format string has been fully checked.
3073	bool CheckFormatArguments(const FormatAttr *Format,
3074	ArrayRef<const Expr > Args, bool* IsCXXMember,
3075	VariadicCallType CallType, SourceLocation Loc,
3076	SourceRange Range,
3077	llvm::SmallBitVector &CheckedVarArgs);
3078	bool CheckFormatString(const FormatMatchesAttr *Format,
3079	ArrayRef<const Expr > Args, bool* IsCXXMember,
3080	VariadicCallType CallType, SourceLocation Loc,
3081	SourceRange Range,
3082	llvm::SmallBitVector &CheckedVarArgs);
3083	bool CheckFormatArguments(ArrayRef<const Expr *> Args,
3084	FormatArgumentPassingKind FAPK,
3085	StringLiteral *ReferenceFormatString,
3086	unsigned format_idx, unsigned firstDataArg,
3087	FormatStringType Type, VariadicCallType CallType,
3088	SourceLocation Loc, SourceRange range,
3089	llvm::SmallBitVector &CheckedVarArgs);
3090
3091	void CheckInfNaNFunction(const CallExpr Call, const* FunctionDecl *FDecl);
3092
3093	/// Warn when using the wrong abs() function.
3094	void CheckAbsoluteValueFunction(const CallExpr *Call,
3095	const FunctionDecl *FDecl);
3096
3097	void CheckMaxUnsignedZero(const CallExpr Call, const* FunctionDecl *FDecl);
3098
3099	/// Check for dangerous or invalid arguments to memset().
3100	///
3101	/// This issues warnings on known problematic, dangerous or unspecified
3102	/// arguments to the standard 'memset', 'memcpy', 'memmove', and 'memcmp'
3103	/// function calls.
3104	///
3105	/// \param Call The call expression to diagnose.
3106	void CheckMemaccessArguments(const CallExpr Call, unsigned* BId,
3107	IdentifierInfo *FnName);
3108
3109	bool CheckSizeofMemaccessArgument(const Expr SizeOfArg, const* Expr *Dest,
3110	IdentifierInfo *FnName);
3111	// Warn if the user has made the 'size' argument to strlcpy or strlcat
3112	// be the size of the source, instead of the destination.
3113	void CheckStrlcpycatArguments(const CallExpr Call, IdentifierInfo FnName);
3114
3115	// Warn on anti-patterns as the 'size' argument to strncat.
3116	// The correct size argument should look like following:
3117	// strncat(dst, src, sizeof(dst) - strlen(dest) - 1);
3118	void CheckStrncatArguments(const CallExpr *Call,
3119	const IdentifierInfo *FnName);
3120
3121	/// Alerts the user that they are attempting to free a non-malloc'd object.
3122	void CheckFreeArguments(const CallExpr *E);
3123
3124	void CheckReturnValExpr(Expr *RetValExp, QualType lhsType,
3125	SourceLocation ReturnLoc, bool isObjCMethod = false,
3126	const AttrVec Attrs = nullptr*,
3127	const FunctionDecl FD = nullptr*);
3128
3129	/// Diagnoses "dangerous" implicit conversions within the given
3130	/// expression (which is a full expression). Implements -Wconversion
3131	/// and -Wsign-compare.
3132	///
3133	/// \param CC the "context" location of the implicit conversion, i.e.
3134	/// the most location of the syntactic entity requiring the implicit
3135	/// conversion
3136	void CheckImplicitConversions(Expr *E, SourceLocation CC = SourceLocation ());
3137
3138	/// CheckBoolLikeConversion - Check conversion of given expression to boolean.
3139	/// Input argument E is a logical expression.
3140	void CheckBoolLikeConversion(Expr *E, SourceLocation CC);
3141
3142	/// Diagnose when expression is an integer constant expression and its
3143	/// evaluation results in integer overflow
3144	void CheckForIntOverflow(const Expr *E);
3145	void CheckUnsequencedOperations(const Expr *E);
3146
3147	/// Perform semantic checks on a completed expression. This will either
3148	/// be a full-expression or a default argument expression.
3149	void CheckCompletedExpr(Expr *E, SourceLocation CheckLoc = SourceLocation (),
3150	bool IsConstexpr = false);
3151
3152	void CheckBitFieldInitialization(SourceLocation InitLoc, FieldDecl *Field,
3153	Expr *Init);
3154
3155	/// A map from magic value to type information.
3156	std::unique_ptr<llvm::DenseMap<TypeTagMagicValue, TypeTagData>>
3157	TypeTagForDatatypeMagicValues;
3158
3159	/// Peform checks on a call of a function with argument_with_type_tag
3160	/// or pointer_with_type_tag attributes.
3161	void CheckArgumentWithTypeTag(const ArgumentWithTypeTagAttr *Attr,
3162	const ArrayRef<const Expr *> ExprArgs,
3163	SourceLocation CallSiteLoc);
3164
3165	/// Check if we are taking the address of a packed field
3166	/// as this may be a problem if the pointer value is dereferenced.
3167	void CheckAddressOfPackedMember(Expr *rhs);
3168
3169	/// Helper class that collects misaligned member designations and
3170	/// their location info for delayed diagnostics.
3171	struct MisalignedMember {
3172	Expr *E;
3173	RecordDecl *RD;
3174	ValueDecl *MD;
3175	CharUnits Alignment;
3176
3177	MisalignedMember() : E(), RD(), MD() {}
3178	MisalignedMember(Expr E, RecordDecl RD, ValueDecl *MD,
3179	CharUnits Alignment)
3180	: E(E), RD(RD), MD(MD), Alignment (Alignment) {}
3181	explicit MisalignedMember(Expr *E)
3182	: MisalignedMember (E, nullptr, nullptr, CharUnits ()) {}
3183
3184	bool operator==(const MisalignedMember &m) { return this->E == m.E; }
3185	};
3186
3187	/// Adds an expression to the set of gathered misaligned members.
3188	void AddPotentialMisalignedMembers(Expr E, RecordDecl RD, ValueDecl *MD,
3189	CharUnits Alignment);
3190	///@}
3191
3192	//
3193	//
3194	// -------------------------------------------------------------------------
3195	//
3196	//
3197
3198	/// \name C++ Coroutines
3199	/// Implementations are in SemaCoroutine.cpp
3200	///@{
3201
3202	public:
3203	/// The C++ "std::coroutine_traits" template, which is defined in
3204	/// \<coroutine_traits>
3205	ClassTemplateDecl *StdCoroutineTraitsCache;
3206
3207	bool ActOnCoroutineBodyStart(Scope *S, SourceLocation KwLoc,
3208	StringRef Keyword);
3209	ExprResult ActOnCoawaitExpr(Scope S, SourceLocation KwLoc, Expr E);
3210	ExprResult ActOnCoyieldExpr(Scope S, SourceLocation KwLoc, Expr E);
3211	StmtResult ActOnCoreturnStmt(Scope S, SourceLocation KwLoc, Expr E);
3212
3213	ExprResult BuildOperatorCoawaitLookupExpr(Scope *S, SourceLocation Loc);
3214	ExprResult BuildOperatorCoawaitCall(SourceLocation Loc, Expr *E,
3215	UnresolvedLookupExpr *Lookup);
3216	ExprResult BuildResolvedCoawaitExpr(SourceLocation KwLoc, Expr *Operand,
3217	Expr Awaiter, bool* IsImplicit = false);
3218	ExprResult BuildUnresolvedCoawaitExpr(SourceLocation KwLoc, Expr *Operand,
3219	UnresolvedLookupExpr *Lookup);
3220	ExprResult BuildCoyieldExpr(SourceLocation KwLoc, Expr *E);
3221	StmtResult BuildCoreturnStmt(SourceLocation KwLoc, Expr *E,
3222	bool IsImplicit = false);
3223	StmtResult BuildCoroutineBodyStmt(CoroutineBodyStmt::CtorArgs);
3224	bool buildCoroutineParameterMoves(SourceLocation Loc);
3225	VarDecl *buildCoroutinePromise(SourceLocation Loc);
3226	void CheckCompletedCoroutineBody(FunctionDecl FD, Stmt &Body);
3227
3228	// As a clang extension, enforces that a non-coroutine function must be marked
3229	// with [[clang::coro_wrapper]] if it returns a type marked with
3230	// [[clang::coro_return_type]].
3231	// Expects that FD is not a coroutine.
3232	void CheckCoroutineWrapper(FunctionDecl *FD);
3233	/// Lookup 'coroutine_traits' in std namespace and std::experimental
3234	/// namespace. The namespace found is recorded in Namespace.
3235	ClassTemplateDecl *lookupCoroutineTraits(SourceLocation KwLoc,
3236	SourceLocation FuncLoc);
3237	/// Check that the expression co_await promise.final_suspend() shall not be
3238	/// potentially-throwing.
3239	bool checkFinalSuspendNoThrow(const Stmt *FinalSuspend);
3240
3241	///@}
3242
3243	//
3244	//
3245	// -------------------------------------------------------------------------
3246	//
3247	//
3248
3249	/// \name C++ Scope Specifiers
3250	/// Implementations are in SemaCXXScopeSpec.cpp
3251	///@{
3252
3253	public:
3254	// Marks SS invalid if it represents an incomplete type.
3255	bool RequireCompleteDeclContext(CXXScopeSpec &SS, DeclContext *DC);
3256	// Complete an enum decl, maybe without a scope spec.
3257	bool RequireCompleteEnumDecl(EnumDecl *D, SourceLocation L,
3258	CXXScopeSpec SS = nullptr*);
3259
3260	/// Compute the DeclContext that is associated with the given type.
3261	///
3262	/// \param T the type for which we are attempting to find a DeclContext.
3263	///
3264	/// \returns the declaration context represented by the type T,
3265	/// or NULL if the declaration context cannot be computed (e.g., because it is
3266	/// dependent and not the current instantiation).
3267	DeclContext *computeDeclContext(QualType T);
3268
3269	/// Compute the DeclContext that is associated with the given
3270	/// scope specifier.
3271	///
3272	/// \param SS the C++ scope specifier as it appears in the source
3273	///
3274	/// \param EnteringContext when true, we will be entering the context of
3275	/// this scope specifier, so we can retrieve the declaration context of a
3276	/// class template or class template partial specialization even if it is
3277	/// not the current instantiation.
3278	///
3279	/// \returns the declaration context represented by the scope specifier @p SS,
3280	/// or NULL if the declaration context cannot be computed (e.g., because it is
3281	/// dependent and not the current instantiation).
3282	DeclContext computeDeclContext(const* CXXScopeSpec &SS,
3283	bool EnteringContext = false);
3284	bool isDependentScopeSpecifier(const CXXScopeSpec &SS);
3285
3286	/// If the given nested name specifier refers to the current
3287	/// instantiation, return the declaration that corresponds to that
3288	/// current instantiation (C++0x [temp.dep.type]p1).
3289	///
3290	/// \param NNS a dependent nested name specifier.
3291	CXXRecordDecl *getCurrentInstantiationOf(NestedNameSpecifier NNS);
3292
3293	/// The parser has parsed a global nested-name-specifier '::'.
3294	///
3295	/// \param CCLoc The location of the '::'.
3296	///
3297	/// \param SS The nested-name-specifier, which will be updated in-place
3298	/// to reflect the parsed nested-name-specifier.
3299	///
3300	/// \returns true if an error occurred, false otherwise.
3301	bool ActOnCXXGlobalScopeSpecifier(SourceLocation CCLoc, CXXScopeSpec &SS);
3302
3303	/// The parser has parsed a '__super' nested-name-specifier.
3304	///
3305	/// \param SuperLoc The location of the '__super' keyword.
3306	///
3307	/// \param ColonColonLoc The location of the '::'.
3308	///
3309	/// \param SS The nested-name-specifier, which will be updated in-place
3310	/// to reflect the parsed nested-name-specifier.
3311	///
3312	/// \returns true if an error occurred, false otherwise.
3313	bool ActOnSuperScopeSpecifier(SourceLocation SuperLoc,
3314	SourceLocation ColonColonLoc, CXXScopeSpec &SS);
3315
3316	/// Determines whether the given declaration is an valid acceptable
3317	/// result for name lookup of a nested-name-specifier.
3318	/// \param SD Declaration checked for nested-name-specifier.
3319	/// \param IsExtension If not null and the declaration is accepted as an
3320	/// extension, the pointed variable is assigned true.
3321	bool isAcceptableNestedNameSpecifier(const NamedDecl *SD,
3322	bool CanCorrect = nullptr*);
3323
3324	/// If the given nested-name-specifier begins with a bare identifier
3325	/// (e.g., Base::), perform name lookup for that identifier as a
3326	/// nested-name-specifier within the given scope, and return the result of
3327	/// that name lookup.
3328	NamedDecl FindFirstQualifierInScope(Scope S, NestedNameSpecifier NNS);
3329
3330	/// Keeps information about an identifier in a nested-name-spec.
3331	///
3332	struct NestedNameSpecInfo {
3333	/// The type of the object, if we're parsing nested-name-specifier in
3334	/// a member access expression.
3335	ParsedType ObjectType;
3336
3337	/// The identifier preceding the '::'.
3338	IdentifierInfo *Identifier;
3339
3340	/// The location of the identifier.
3341	SourceLocation IdentifierLoc;
3342
3343	/// The location of the '::'.
3344	SourceLocation CCLoc;
3345
3346	/// Creates info object for the most typical case.
3347	NestedNameSpecInfo(IdentifierInfo *II, SourceLocation IdLoc,
3348	SourceLocation ColonColonLoc,
3349	ParsedType ObjectType = ParsedType ())
3350	: ObjectType (ObjectType), Identifier(II), IdentifierLoc (IdLoc),
3351	CCLoc (ColonColonLoc) {}
3352
3353	NestedNameSpecInfo(IdentifierInfo *II, SourceLocation IdLoc,
3354	SourceLocation ColonColonLoc, QualType ObjectType)
3355	: ObjectType(ParsedType::make(P: ObjectType)), Identifier(II),
3356	IdentifierLoc (IdLoc), CCLoc (ColonColonLoc) {}
3357	};
3358
3359	/// Build a new nested-name-specifier for "identifier::", as described
3360	/// by ActOnCXXNestedNameSpecifier.
3361	///
3362	/// \param S Scope in which the nested-name-specifier occurs.
3363	/// \param IdInfo Parser information about an identifier in the
3364	/// nested-name-spec.
3365	/// \param EnteringContext If true, enter the context specified by the
3366	/// nested-name-specifier.
3367	/// \param SS Optional nested name specifier preceding the identifier.
3368	/// \param ScopeLookupResult Provides the result of name lookup within the
3369	/// scope of the nested-name-specifier that was computed at template
3370	/// definition time.
3371	/// \param ErrorRecoveryLookup Specifies if the method is called to improve
3372	/// error recovery and what kind of recovery is performed.
3373	/// \param IsCorrectedToColon If not null, suggestion of replace '::' -> ':'
3374	/// are allowed. The bool value pointed by this parameter is set to
3375	/// 'true' if the identifier is treated as if it was followed by ':',
3376	/// not '::'.
3377	/// \param OnlyNamespace If true, only considers namespaces in lookup.
3378	///
3379	/// This routine differs only slightly from ActOnCXXNestedNameSpecifier, in
3380	/// that it contains an extra parameter \p ScopeLookupResult, which provides
3381	/// the result of name lookup within the scope of the nested-name-specifier
3382	/// that was computed at template definition time.
3383	///
3384	/// If ErrorRecoveryLookup is true, then this call is used to improve error
3385	/// recovery. This means that it should not emit diagnostics, it should
3386	/// just return true on failure. It also means it should only return a valid
3387	/// scope if it knows* that the result is correct. It should not return in a*
3388	/// dependent context, for example. Nor will it extend \p SS with the scope
3389	/// specifier.
3390	bool BuildCXXNestedNameSpecifier(Scope *S, NestedNameSpecInfo &IdInfo,
3391	bool EnteringContext, CXXScopeSpec &SS,
3392	NamedDecl *ScopeLookupResult,
3393	bool ErrorRecoveryLookup,
3394	bool IsCorrectedToColon = nullptr*,
3395	bool OnlyNamespace = false);
3396
3397	/// The parser has parsed a nested-name-specifier 'identifier::'.
3398	///
3399	/// \param S The scope in which this nested-name-specifier occurs.
3400	///
3401	/// \param IdInfo Parser information about an identifier in the
3402	/// nested-name-spec.
3403	///
3404	/// \param EnteringContext Whether we're entering the context nominated by
3405	/// this nested-name-specifier.
3406	///
3407	/// \param SS The nested-name-specifier, which is both an input
3408	/// parameter (the nested-name-specifier before this type) and an
3409	/// output parameter (containing the full nested-name-specifier,
3410	/// including this new type).
3411	///
3412	/// \param IsCorrectedToColon If not null, suggestions to replace '::' -> ':'
3413	/// are allowed. The bool value pointed by this parameter is set to 'true'
3414	/// if the identifier is treated as if it was followed by ':', not '::'.
3415	///
3416	/// \param OnlyNamespace If true, only considers namespaces in lookup.
3417	///
3418	/// \returns true if an error occurred, false otherwise.
3419	bool ActOnCXXNestedNameSpecifier(Scope *S, NestedNameSpecInfo &IdInfo,
3420	bool EnteringContext, CXXScopeSpec &SS,
3421	bool IsCorrectedToColon = nullptr*,
3422	bool OnlyNamespace = false);
3423
3424	/// The parser has parsed a nested-name-specifier
3425	/// 'template[opt] template-name < template-args >::'.
3426	///
3427	/// \param S The scope in which this nested-name-specifier occurs.
3428	///
3429	/// \param SS The nested-name-specifier, which is both an input
3430	/// parameter (the nested-name-specifier before this type) and an
3431	/// output parameter (containing the full nested-name-specifier,
3432	/// including this new type).
3433	///
3434	/// \param TemplateKWLoc the location of the 'template' keyword, if any.
3435	/// \param TemplateName the template name.
3436	/// \param TemplateNameLoc The location of the template name.
3437	/// \param LAngleLoc The location of the opening angle bracket ('<').
3438	/// \param TemplateArgs The template arguments.
3439	/// \param RAngleLoc The location of the closing angle bracket ('>').
3440	/// \param CCLoc The location of the '::'.
3441	///
3442	/// \param EnteringContext Whether we're entering the context of the
3443	/// nested-name-specifier.
3444	///
3445	///
3446	/// \returns true if an error occurred, false otherwise.
3447	bool ActOnCXXNestedNameSpecifier(
3448	Scope *S, CXXScopeSpec &SS, SourceLocation TemplateKWLoc,
3449	TemplateTy TemplateName, SourceLocation TemplateNameLoc,
3450	SourceLocation LAngleLoc, ASTTemplateArgsPtr TemplateArgs,
3451	SourceLocation RAngleLoc, SourceLocation CCLoc, bool EnteringContext);
3452
3453	bool ActOnCXXNestedNameSpecifierDecltype(CXXScopeSpec &SS, const DeclSpec &DS,
3454	SourceLocation ColonColonLoc);
3455
3456	bool ActOnCXXNestedNameSpecifierIndexedPack(CXXScopeSpec &SS,
3457	const DeclSpec &DS,
3458	SourceLocation ColonColonLoc,
3459	QualType Type);
3460
3461	/// IsInvalidUnlessNestedName - This method is used for error recovery
3462	/// purposes to determine whether the specified identifier is only valid as
3463	/// a nested name specifier, for example a namespace name. It is
3464	/// conservatively correct to always return false from this method.
3465	///
3466	/// The arguments are the same as those passed to ActOnCXXNestedNameSpecifier.
3467	bool IsInvalidUnlessNestedName(Scope *S, CXXScopeSpec &SS,
3468	NestedNameSpecInfo &IdInfo,
3469	bool EnteringContext);
3470
3471	/// Given a C++ nested-name-specifier, produce an annotation value
3472	/// that the parser can use later to reconstruct the given
3473	/// nested-name-specifier.
3474	///
3475	/// \param SS A nested-name-specifier.
3476	///
3477	/// \returns A pointer containing all of the information in the
3478	/// nested-name-specifier \p SS.
3479	void *SaveNestedNameSpecifierAnnotation(CXXScopeSpec &SS);
3480
3481	/// Given an annotation pointer for a nested-name-specifier, restore
3482	/// the nested-name-specifier structure.
3483	///
3484	/// \param Annotation The annotation pointer, produced by
3485	/// \c SaveNestedNameSpecifierAnnotation().
3486	///
3487	/// \param AnnotationRange The source range corresponding to the annotation.
3488	///
3489	/// \param SS The nested-name-specifier that will be updated with the contents
3490	/// of the annotation pointer.
3491	void RestoreNestedNameSpecifierAnnotation(void *Annotation,
3492	SourceRange AnnotationRange,
3493	CXXScopeSpec &SS);
3494
3495	bool ShouldEnterDeclaratorScope(Scope S, const* CXXScopeSpec &SS);
3496
3497	/// ActOnCXXEnterDeclaratorScope - Called when a C++ scope specifier (global
3498	/// scope or nested-name-specifier) is parsed, part of a declarator-id.
3499	/// After this method is called, according to [C++ 3.4.3p3], names should be
3500	/// looked up in the declarator-id's scope, until the declarator is parsed and
3501	/// ActOnCXXExitDeclaratorScope is called.
3502	/// The 'SS' should be a non-empty valid CXXScopeSpec.
3503	bool ActOnCXXEnterDeclaratorScope(Scope *S, CXXScopeSpec &SS);
3504
3505	/// ActOnCXXExitDeclaratorScope - Called when a declarator that previously
3506	/// invoked ActOnCXXEnterDeclaratorScope(), is finished. 'SS' is the same
3507	/// CXXScopeSpec that was passed to ActOnCXXEnterDeclaratorScope as well.
3508	/// Used to indicate that names should revert to being looked up in the
3509	/// defining scope.
3510	void ActOnCXXExitDeclaratorScope(Scope S, const* CXXScopeSpec &SS);
3511
3512	///@}
3513
3514	//
3515	//
3516	// -------------------------------------------------------------------------
3517	//
3518	//
3519
3520	/// \name Declarations
3521	/// Implementations are in SemaDecl.cpp
3522	///@{
3523
3524	public:
3525	IdentifierResolver IdResolver;
3526
3527	/// The index of the first InventedParameterInfo that refers to the current
3528	/// context.
3529	unsigned InventedParameterInfosStart = `0`;
3530
3531	/// A RAII object to temporarily push a declaration context.
3532	class ContextRAII {
3533	private:
3534	Sema &S;
3535	DeclContext *SavedContext;
3536	ProcessingContextState SavedContextState;
3537	QualType SavedCXXThisTypeOverride;
3538	unsigned SavedFunctionScopesStart;
3539	unsigned SavedInventedParameterInfosStart;
3540
3541	public:
3542	ContextRAII(Sema &S, DeclContext ContextToPush, bool* NewThisContext = true)
3543	: S(S), SavedContext(S.CurContext),
3544	SavedContextState(S.DelayedDiagnostics.pushUndelayed()),
3545	SavedCXXThisTypeOverride (S.CXXThisTypeOverride),
3546	SavedFunctionScopesStart(S.FunctionScopesStart),
3547	SavedInventedParameterInfosStart(S.InventedParameterInfosStart) {
3548	assert(ContextToPush && "pushing null context");
3549	S.CurContext = ContextToPush;
3550	if (NewThisContext)
3551	S.CXXThisTypeOverride = QualType ();
3552	// Any saved FunctionScopes do not refer to this context.
3553	S.FunctionScopesStart = S.FunctionScopes.size();
3554	S.InventedParameterInfosStart = S.InventedParameterInfos.size();
3555	}
3556
3557	void pop() {
3558	if (!SavedContext)
3559	return;
3560	S.CurContext = SavedContext;
3561	S.DelayedDiagnostics.popUndelayed(state: SavedContextState);
3562	S.CXXThisTypeOverride = SavedCXXThisTypeOverride;
3563	S.FunctionScopesStart = SavedFunctionScopesStart;
3564	S.InventedParameterInfosStart = SavedInventedParameterInfosStart;
3565	SavedContext = nullptr;
3566	}
3567
3568	~ContextRAII() { pop(); }
3569	ContextRAII(const ContextRAII &) = delete;
3570	ContextRAII &operator=(const ContextRAII &) = delete;
3571	};
3572
3573	void DiagnoseInvalidJumps(Stmt *Body);
3574
3575	/// The function definitions which were renamed as part of typo-correction
3576	/// to match their respective declarations. We want to keep track of them
3577	/// to ensure that we don't emit a "redefinition" error if we encounter a
3578	/// correctly named definition after the renamed definition.
3579	llvm::SmallPtrSet<const NamedDecl *, `4`> TypoCorrectedFunctionDefinitions;
3580
3581	/// A cache of the flags available in enumerations with the flag_enum
3582	/// attribute.
3583	llvm::DenseMap<const EnumDecl *, llvm::APInt> FlagBitsCache;
3584
3585	/// A cache of enumerator values for enums checked by -Wassign-enum.
3586	llvm::DenseMap<const EnumDecl *, llvm::SmallVector<llvm::APSInt>>
3587	AssignEnumCache;
3588
3589	/// WeakUndeclaredIdentifiers - Identifiers contained in \#pragma weak before
3590	/// declared. Rare. May alias another identifier, declared or undeclared.
3591	///
3592	/// For aliases, the target identifier is used as a key for eventual
3593	/// processing when the target is declared. For the single-identifier form,
3594	/// the sole identifier is used as the key. Each entry is a `SetVector`
3595	/// (ordered by parse order) of aliases (identified by the alias name) in case
3596	/// of multiple aliases to the same undeclared identifier.
3597	llvm::MapVector<
3598	IdentifierInfo *,
3599	llvm::SetVector<
3600	WeakInfo, llvm::SmallVector<WeakInfo, `1u`>,
3601	llvm::SmallDenseSet<WeakInfo, `2u`, WeakInfo::DenseMapInfoByAliasOnly>>>
3602	WeakUndeclaredIdentifiers;
3603
3604	/// ExtnameUndeclaredIdentifiers - Identifiers contained in
3605	/// \#pragma redefine_extname before declared. Used in Solaris system headers
3606	/// to define functions that occur in multiple standards to call the version
3607	/// in the currently selected standard.
3608	llvm::MapVector<IdentifierInfo , AsmLabelAttr >
3609	ExtnameUndeclaredIdentifiers;
3610
3611	/// Set containing all typedefs that are likely unused.
3612	llvm::SmallPtrSet<const TypedefNameDecl *, `4`>
3613	UnusedLocalTypedefNameCandidates;
3614
3615	/// Store UnusedLocalTypedefNameCandidates in \p Sorted in a deterministic
3616	/// order.
3617	void getSortedUnusedLocalTypedefNameCandidates(
3618	SmallVectorImpl<const TypedefNameDecl > &Sorted) const*;
3619
3620	typedef LazyVector<const DeclaratorDecl *,
3621	&ExternalSemaSource::ReadUnusedFileScopedDecls, `2`, `2`>
3622	UnusedFileScopedDeclsType;
3623
3624	/// The set of file scoped decls seen so far that have not been used
3625	/// and must warn if not used. Only contains the first declaration.
3626	UnusedFileScopedDeclsType UnusedFileScopedDecls;
3627
3628	typedef LazyVector<VarDecl *, &ExternalSemaSource::ReadTentativeDefinitions,
3629	`2`, `2`>
3630	TentativeDefinitionsType;
3631
3632	/// All the tentative definitions encountered in the TU.
3633	TentativeDefinitionsType TentativeDefinitions;
3634
3635	/// All the external declarations encoutered and used in the TU.
3636	SmallVector<DeclaratorDecl *, `4`> ExternalDeclarations;
3637
3638	/// Generally null except when we temporarily switch decl contexts,
3639	/// like in \see SemaObjC::ActOnObjCTemporaryExitContainerContext.
3640	DeclContext *OriginalLexicalContext;
3641
3642	/// Is the module scope we are in a C++ Header Unit?
3643	bool currentModuleIsHeaderUnit() const {
3644	return ModuleScopes.empty() ? false
3645	: ModuleScopes.back().Module->isHeaderUnit();
3646	}
3647
3648	/// Get the module owning an entity.
3649	Module getOwningModule(const* Decl *Entity) {
3650	return Entity->getOwningModule();
3651	}
3652
3653	DeclGroupPtrTy ConvertDeclToDeclGroup(Decl Ptr, Decl OwnedType = nullptr);
3654
3655	enum class DiagCtorKind { None, Implicit, Typename };
3656	/// Returns the TypeDeclType for the given type declaration,
3657	/// as ASTContext::getTypeDeclType would, but
3658	/// performs the required semantic checks for name lookup of said entity.
3659	void checkTypeDeclType(DeclContext LookupCtx, DiagCtorKind DCK, TypeDecl TD,
3660	SourceLocation NameLoc);
3661
3662	/// If the identifier refers to a type name within this scope,
3663	/// return the declaration of that type.
3664	///
3665	/// This routine performs ordinary name lookup of the identifier II
3666	/// within the given scope, with optional C++ scope specifier SS, to
3667	/// determine whether the name refers to a type. If so, returns an
3668	/// opaque pointer (actually a QualType) corresponding to that
3669	/// type. Otherwise, returns NULL.
3670	ParsedType getTypeName(const IdentifierInfo &II, SourceLocation NameLoc,
3671	Scope S, CXXScopeSpec SS = nullptr,
3672	bool isClassName = false, bool HasTrailingDot = false,
3673	ParsedType ObjectType = nullptr,
3674	bool IsCtorOrDtorName = false,
3675	bool WantNontrivialTypeSourceInfo = false,
3676	bool IsClassTemplateDeductionContext = true,
3677	ImplicitTypenameContext AllowImplicitTypename =
3678	ImplicitTypenameContext::No,
3679	IdentifierInfo CorrectedII = nullptr**);
3680
3681	/// isTagName() - This method is called for error recovery purposes only
3682	/// to determine if the specified name is a valid tag name ("struct foo"). If
3683	/// so, this returns the TST for the tag corresponding to it (TST_enum,
3684	/// TST_union, TST_struct, TST_interface, TST_class). This is used to
3685	/// diagnose cases in C where the user forgot to specify the tag.
3686	TypeSpecifierType isTagName(IdentifierInfo &II, Scope *S);
3687
3688	/// isMicrosoftMissingTypename - In Microsoft mode, within class scope,
3689	/// if a CXXScopeSpec's type is equal to the type of one of the base classes
3690	/// then downgrade the missing typename error to a warning.
3691	/// This is needed for MSVC compatibility; Example:
3692	/// @code
3693	/// template<class T> class A {
3694	/// public:
3695	/// typedef int TYPE;
3696	/// };
3697	/// template<class T> class B : public A<T> {
3698	/// public:
3699	/// A<T>::TYPE a; // no typename required because A<T> is a base class.
3700	/// };
3701	/// @endcode
3702	bool isMicrosoftMissingTypename(const CXXScopeSpec SS, Scope S);
3703	void DiagnoseUnknownTypeName(IdentifierInfo *&II, SourceLocation IILoc,
3704	Scope S, CXXScopeSpec SS,
3705	ParsedType &SuggestedType,
3706	bool IsTemplateName = false);
3707
3708	/// Attempt to behave like MSVC in situations where lookup of an unqualified
3709	/// type name has failed in a dependent context. In these situations, we
3710	/// automatically form a DependentTypeName that will retry lookup in a related
3711	/// scope during instantiation.
3712	ParsedType ActOnMSVCUnknownTypeName(const IdentifierInfo &II,
3713	SourceLocation NameLoc,
3714	bool IsTemplateTypeArg);
3715
3716	class NameClassification {
3717	NameClassificationKind Kind;
3718	union {
3719	ExprResult Expr;
3720	NamedDecl *NonTypeDecl;
3721	TemplateName Template;
3722	ParsedType Type;
3723	};
3724
3725	explicit NameClassification(NameClassificationKind Kind) : Kind(Kind) {}
3726
3727	public:
3728	NameClassification(ParsedType Type)
3729	: Kind(NameClassificationKind::Type), Type (Type) {}
3730
3731	NameClassification(const IdentifierInfo *Keyword)
3732	: Kind(NameClassificationKind::Keyword) {}
3733
3734	static NameClassification Error() {
3735	return NameClassification (NameClassificationKind::Error);
3736	}
3737
3738	static NameClassification Unknown() {
3739	return NameClassification (NameClassificationKind::Unknown);
3740	}
3741
3742	static NameClassification OverloadSet(ExprResult E) {
3743	NameClassification Result(NameClassificationKind::OverloadSet);
3744	Result.Expr = E;
3745	return Result;
3746	}
3747
3748	static NameClassification NonType(NamedDecl *D) {
3749	NameClassification Result(NameClassificationKind::NonType);
3750	Result.NonTypeDecl = D;
3751	return Result;
3752	}
3753
3754	static NameClassification UndeclaredNonType() {
3755	return NameClassification (NameClassificationKind::UndeclaredNonType);
3756	}
3757
3758	static NameClassification DependentNonType() {
3759	return NameClassification (NameClassificationKind::DependentNonType);
3760	}
3761
3762	static NameClassification TypeTemplate(TemplateName Name) {
3763	NameClassification Result(NameClassificationKind::TypeTemplate);
3764	Result.Template = Name;
3765	return Result;
3766	}
3767
3768	static NameClassification VarTemplate(TemplateName Name) {
3769	NameClassification Result(NameClassificationKind::VarTemplate);
3770	Result.Template = Name;
3771	return Result;
3772	}
3773
3774	static NameClassification FunctionTemplate(TemplateName Name) {
3775	NameClassification Result(NameClassificationKind::FunctionTemplate);
3776	Result.Template = Name;
3777	return Result;
3778	}
3779
3780	static NameClassification Concept(TemplateName Name) {
3781	NameClassification Result(NameClassificationKind::Concept);
3782	Result.Template = Name;
3783	return Result;
3784	}
3785
3786	static NameClassification UndeclaredTemplate(TemplateName Name) {
3787	NameClassification Result(NameClassificationKind::UndeclaredTemplate);
3788	Result.Template = Name;
3789	return Result;
3790	}
3791
3792	NameClassificationKind getKind() const { return Kind; }
3793
3794	ExprResult getExpression() const {
3795	assert(Kind == NameClassificationKind::OverloadSet);
3796	return Expr;
3797	}
3798
3799	ParsedType getType() const {
3800	assert(Kind == NameClassificationKind::Type);
3801	return Type;
3802	}
3803
3804	NamedDecl getNonTypeDecl() const* {
3805	assert(Kind == NameClassificationKind::NonType);
3806	return NonTypeDecl;
3807	}
3808
3809	TemplateName getTemplateName() const {
3810	assert(Kind == NameClassificationKind::TypeTemplate \|\|
3811	Kind == NameClassificationKind::FunctionTemplate \|\|
3812	Kind == NameClassificationKind::VarTemplate \|\|
3813	Kind == NameClassificationKind::Concept \|\|
3814	Kind == NameClassificationKind::UndeclaredTemplate);
3815	return Template;
3816	}
3817
3818	TemplateNameKind getTemplateNameKind() const {
3819	switch (Kind) {
3820	case NameClassificationKind::TypeTemplate:
3821	return TNK_Type_template;
3822	case NameClassificationKind::FunctionTemplate:
3823	return TNK_Function_template;
3824	case NameClassificationKind::VarTemplate:
3825	return TNK_Var_template;
3826	case NameClassificationKind::Concept:
3827	return TNK_Concept_template;
3828	case NameClassificationKind::UndeclaredTemplate:
3829	return TNK_Undeclared_template;
3830	default:
3831	llvm_unreachable("unsupported name classification.");
3832	}
3833	}
3834	};
3835
3836	/// Perform name lookup on the given name, classifying it based on
3837	/// the results of name lookup and the following token.
3838	///
3839	/// This routine is used by the parser to resolve identifiers and help direct
3840	/// parsing. When the identifier cannot be found, this routine will attempt
3841	/// to correct the typo and classify based on the resulting name.
3842	///
3843	/// \param S The scope in which we're performing name lookup.
3844	///
3845	/// \param SS The nested-name-specifier that precedes the name.
3846	///
3847	/// \param Name The identifier. If typo correction finds an alternative name,
3848	/// this pointer parameter will be updated accordingly.
3849	///
3850	/// \param NameLoc The location of the identifier.
3851	///
3852	/// \param NextToken The token following the identifier. Used to help
3853	/// disambiguate the name.
3854	///
3855	/// \param CCC The correction callback, if typo correction is desired.
3856	NameClassification ClassifyName(Scope *S, CXXScopeSpec &SS,
3857	IdentifierInfo *&Name, SourceLocation NameLoc,
3858	const Token &NextToken,
3859	CorrectionCandidateCallback CCC = nullptr*);
3860
3861	/// Act on the result of classifying a name as an undeclared (ADL-only)
3862	/// non-type declaration.
3863	ExprResult ActOnNameClassifiedAsUndeclaredNonType(IdentifierInfo *Name,
3864	SourceLocation NameLoc);
3865	/// Act on the result of classifying a name as an undeclared member of a
3866	/// dependent base class.
3867	ExprResult ActOnNameClassifiedAsDependentNonType(const CXXScopeSpec &SS,
3868	IdentifierInfo *Name,
3869	SourceLocation NameLoc,
3870	bool IsAddressOfOperand);
3871	/// Act on the result of classifying a name as a specific non-type
3872	/// declaration.
3873	ExprResult ActOnNameClassifiedAsNonType(Scope S, const* CXXScopeSpec &SS,
3874	NamedDecl *Found,
3875	SourceLocation NameLoc,
3876	const Token &NextToken);
3877	/// Act on the result of classifying a name as an overload set.
3878	ExprResult ActOnNameClassifiedAsOverloadSet(Scope S, Expr OverloadSet);
3879
3880	/// Describes the detailed kind of a template name. Used in diagnostics.
3881	enum class TemplateNameKindForDiagnostics {
3882	ClassTemplate,
3883	FunctionTemplate,
3884	VarTemplate,
3885	AliasTemplate,
3886	TemplateTemplateParam,
3887	Concept,
3888	DependentTemplate
3889	};
3890	TemplateNameKindForDiagnostics
3891	getTemplateNameKindForDiagnostics(TemplateName Name);
3892
3893	/// Determine whether it's plausible that E was intended to be a
3894	/// template-name.
3895	bool mightBeIntendedToBeTemplateName(ExprResult E, bool &Dependent) {
3896	if (!getLangOpts().CPlusPlus \|\| E.isInvalid())
3897	return false;
3898	Dependent = false;
3899	if (auto *DRE = dyn_cast<DeclRefExpr>(Val: E.get()))
3900	return !DRE->hasExplicitTemplateArgs();
3901	if (auto *ME = dyn_cast<MemberExpr>(Val: E.get()))
3902	return !ME->hasExplicitTemplateArgs();
3903	Dependent = true;
3904	if (auto *DSDRE = dyn_cast<DependentScopeDeclRefExpr>(Val: E.get()))
3905	return !DSDRE->hasExplicitTemplateArgs();
3906	if (auto *DSME = dyn_cast<CXXDependentScopeMemberExpr>(Val: E.get()))
3907	return !DSME->hasExplicitTemplateArgs();
3908	// Any additional cases recognized here should also be handled by
3909	// diagnoseExprIntendedAsTemplateName.
3910	return false;
3911	}
3912
3913	void warnOnReservedIdentifier(const NamedDecl *D);
3914	void warnOnCTypeHiddenInCPlusPlus(const NamedDecl *D);
3915
3916	void ProcessPragmaExport(DeclaratorDecl *newDecl);
3917
3918	Decl ActOnDeclarator(Scope S, Declarator &D);
3919
3920	NamedDecl HandleDeclarator(Scope S, Declarator &D,
3921	MultiTemplateParamsArg TemplateParameterLists);
3922
3923	/// Attempt to fold a variable-sized type to a constant-sized type, returning
3924	/// true if we were successful.
3925	bool tryToFixVariablyModifiedVarType(TypeSourceInfo *&TInfo, QualType &T,
3926	SourceLocation Loc,
3927	unsigned FailedFoldDiagID);
3928
3929	/// Register the given locally-scoped extern "C" declaration so
3930	/// that it can be found later for redeclarations. We include any extern "C"
3931	/// declaration that is not visible in the translation unit here, not just
3932	/// function-scope declarations.
3933	void RegisterLocallyScopedExternCDecl(NamedDecl ND, Scope S);
3934
3935	/// DiagnoseClassNameShadow - Implement C++ [class.mem]p13:
3936	/// If T is the name of a class, then each of the following shall have a
3937	/// name different from T:
3938	/// - every static data member of class T;
3939	/// - every member function of class T
3940	/// - every member of class T that is itself a type;
3941	/// \returns true if the declaration name violates these rules.
3942	bool DiagnoseClassNameShadow(DeclContext *DC, DeclarationNameInfo Info);
3943
3944	/// Diagnose a declaration whose declarator-id has the given
3945	/// nested-name-specifier.
3946	///
3947	/// \param SS The nested-name-specifier of the declarator-id.
3948	///
3949	/// \param DC The declaration context to which the nested-name-specifier
3950	/// resolves.
3951	///
3952	/// \param Name The name of the entity being declared.
3953	///
3954	/// \param Loc The location of the name of the entity being declared.
3955	///
3956	/// \param IsMemberSpecialization Whether we are declaring a member
3957	/// specialization.
3958	///
3959	/// \param TemplateId The template-id, if any.
3960	///
3961	/// \returns true if we cannot safely recover from this error, false
3962	/// otherwise.
3963	bool diagnoseQualifiedDeclaration(CXXScopeSpec &SS, DeclContext *DC,
3964	DeclarationName Name, SourceLocation Loc,
3965	TemplateIdAnnotation *TemplateId,
3966	bool IsMemberSpecialization);
3967
3968	bool checkPointerAuthEnabled(SourceLocation Loc, SourceRange Range);
3969
3970	bool checkConstantPointerAuthKey(Expr keyExpr, unsigned* &key);
3971
3972	bool checkPointerAuthDiscriminatorArg(Expr *Arg, PointerAuthDiscArgKind Kind,
3973	unsigned &IntVal);
3974
3975	/// Diagnose function specifiers on a declaration of an identifier that
3976	/// does not identify a function.
3977	void DiagnoseFunctionSpecifiers(const DeclSpec &DS);
3978
3979	/// Return the declaration shadowed by the given typedef \p D, or null
3980	/// if it doesn't shadow any declaration or shadowing warnings are disabled.
3981	NamedDecl getShadowedDeclaration(const* TypedefNameDecl *D,
3982	const LookupResult &R);
3983
3984	/// Return the declaration shadowed by the given variable \p D, or null
3985	/// if it doesn't shadow any declaration or shadowing warnings are disabled.
3986	NamedDecl getShadowedDeclaration(const* VarDecl D, const* LookupResult &R);
3987
3988	/// Return the declaration shadowed by the given variable \p D, or null
3989	/// if it doesn't shadow any declaration or shadowing warnings are disabled.
3990	NamedDecl getShadowedDeclaration(const* BindingDecl *D,
3991	const LookupResult &R);
3992	/// Diagnose variable or built-in function shadowing. Implements
3993	/// -Wshadow.
3994	///
3995	/// This method is called whenever a VarDecl is added to a "useful"
3996	/// scope.
3997	///
3998	/// \param ShadowedDecl the declaration that is shadowed by the given variable
3999	/// \param R the lookup of the name
4000	void CheckShadow(NamedDecl D, NamedDecl ShadowedDecl,
4001	const LookupResult &R);
4002
4003	/// Check -Wshadow without the advantage of a previous lookup.
4004	void CheckShadow(Scope S, VarDecl D);
4005
4006	/// Warn if 'E', which is an expression that is about to be modified, refers
4007	/// to a shadowing declaration.
4008	void CheckShadowingDeclModification(Expr *E, SourceLocation Loc);
4009
4010	/// Diagnose shadowing for variables shadowed in the lambda record \p LambdaRD
4011	/// when these variables are captured by the lambda.
4012	void DiagnoseShadowingLambdaDecls(const sema::LambdaScopeInfo *LSI);
4013
4014	void handleTagNumbering(const TagDecl Tag, Scope TagScope);
4015	void setTagNameForLinkagePurposes(TagDecl *TagFromDeclSpec,
4016	TypedefNameDecl *NewTD);
4017	void CheckTypedefForVariablyModifiedType(Scope S, TypedefNameDecl D);
4018	NamedDecl ActOnTypedefDeclarator(Scope S, Declarator &D, DeclContext *DC,
4019	TypeSourceInfo *TInfo,
4020	LookupResult &Previous);
4021
4022	/// ActOnTypedefNameDecl - Perform semantic checking for a declaration which
4023	/// declares a typedef-name, either using the 'typedef' type specifier or via
4024	/// a C++0x [dcl.typedef]p2 alias-declaration: 'using T = A;'.
4025	NamedDecl ActOnTypedefNameDecl(Scope S, DeclContext DC, TypedefNameDecl D,
4026	LookupResult &Previous, bool &Redeclaration);
4027	NamedDecl ActOnVariableDeclarator(Scope S, Declarator &D, DeclContext *DC,
4028	TypeSourceInfo *TInfo,
4029	LookupResult &Previous,
4030	MultiTemplateParamsArg TemplateParamLists,
4031	bool &AddToScope,
4032	ArrayRef<BindingDecl *> Bindings = {});
4033
4034	private:
4035	// Perform a check on an AsmLabel to verify its consistency and emit
4036	// diagnostics in case of an error.
4037	void CheckAsmLabel(Scope S, Expr AsmLabelExpr, StorageClass SC,
4038	TypeSourceInfo TInfo, VarDecl );
4039
4040	public:
4041	/// Perform semantic checking on a newly-created variable
4042	/// declaration.
4043	///
4044	/// This routine performs all of the type-checking required for a
4045	/// variable declaration once it has been built. It is used both to
4046	/// check variables after they have been parsed and their declarators
4047	/// have been translated into a declaration, and to check variables
4048	/// that have been instantiated from a template.
4049	///
4050	/// Sets NewVD->isInvalidDecl() if an error was encountered.
4051	///
4052	/// Returns true if the variable declaration is a redeclaration.
4053	bool CheckVariableDeclaration(VarDecl *NewVD, LookupResult &Previous);
4054	void CheckVariableDeclarationType(VarDecl *NewVD);
4055	void CheckCompleteVariableDeclaration(VarDecl *VD);
4056
4057	NamedDecl ActOnFunctionDeclarator(Scope S, Declarator &D, DeclContext *DC,
4058	TypeSourceInfo *TInfo,
4059	LookupResult &Previous,
4060	MultiTemplateParamsArg TemplateParamLists,
4061	bool &AddToScope);
4062
4063	/// Attach the ABI tag a standard calling convention variant requires, as an
4064	/// implicit abi_tag attribute. Call this once the function type is final.
4065	void addImplicitCallingConvAbiTag(FunctionDecl *FD);
4066
4067	/// AddOverriddenMethods - See if a method overrides any in the base classes,
4068	/// and if so, check that it's a valid override and remember it.
4069	bool AddOverriddenMethods(CXXRecordDecl DC, CXXMethodDecl MD);
4070
4071	/// Perform semantic checking of a new function declaration.
4072	///
4073	/// Performs semantic analysis of the new function declaration
4074	/// NewFD. This routine performs all semantic checking that does not
4075	/// require the actual declarator involved in the declaration, and is
4076	/// used both for the declaration of functions as they are parsed
4077	/// (called via ActOnDeclarator) and for the declaration of functions
4078	/// that have been instantiated via C++ template instantiation (called
4079	/// via InstantiateDecl).
4080	///
4081	/// \param IsMemberSpecialization whether this new function declaration is
4082	/// a member specialization (that replaces any definition provided by the
4083	/// previous declaration).
4084	///
4085	/// This sets NewFD->isInvalidDecl() to true if there was an error.
4086	///
4087	/// \returns true if the function declaration is a redeclaration.
4088	bool CheckFunctionDeclaration(Scope S, FunctionDecl NewFD,
4089	LookupResult &Previous,
4090	bool IsMemberSpecialization, bool DeclIsDefn);
4091
4092	/// Checks if the new declaration declared in dependent context must be
4093	/// put in the same redeclaration chain as the specified declaration.
4094	///
4095	/// \param D Declaration that is checked.
4096	/// \param PrevDecl Previous declaration found with proper lookup method for
4097	/// the same declaration name.
4098	/// \returns True if D must be added to the redeclaration chain which PrevDecl
4099	/// belongs to.
4100	bool shouldLinkDependentDeclWithPrevious(Decl D, Decl OldDecl);
4101
4102	/// Determines if we can perform a correct type check for \p D as a
4103	/// redeclaration of \p PrevDecl. If not, we can generally still perform a
4104	/// best-effort check.
4105	///
4106	/// \param NewD The new declaration.
4107	/// \param OldD The old declaration.
4108	/// \param NewT The portion of the type of the new declaration to check.
4109	/// \param OldT The portion of the type of the old declaration to check.
4110	bool canFullyTypeCheckRedeclaration(ValueDecl NewD, ValueDecl OldD,
4111	QualType NewT, QualType OldT);
4112	void CheckMain(FunctionDecl FD, const* DeclSpec &D);
4113	void CheckMSVCRTEntryPoint(FunctionDecl *FD);
4114
4115	/// Returns an implicit CodeSegAttr if a __declspec(code_seg) is found on a
4116	/// containing class. Otherwise it will return implicit SectionAttr if the
4117	/// function is a definition and there is an active value on CodeSegStack
4118	/// (from the current #pragma code-seg value).
4119	///
4120	/// \param FD Function being declared.
4121	/// \param IsDefinition Whether it is a definition or just a declaration.
4122	/// \returns A CodeSegAttr or SectionAttr to apply to the function or
4123	/// nullptr if no attribute should be added.
4124	Attr getImplicitCodeSegOrSectionAttrForFunction(const* FunctionDecl *FD,
4125	bool IsDefinition);
4126
4127	/// Common checks for a parameter-declaration that should apply to both
4128	/// function parameters and non-type template parameters.
4129	void CheckFunctionOrTemplateParamDeclarator(Scope *S, Declarator &D);
4130
4131	/// ActOnParamDeclarator - Called from Parser::ParseFunctionDeclarator()
4132	/// to introduce parameters into function prototype scope.
4133	Decl ActOnParamDeclarator(Scope S, Declarator &D,
4134	SourceLocation ExplicitThisLoc = {});
4135
4136	/// Synthesizes a variable for a parameter arising from a
4137	/// typedef.
4138	ParmVarDecl BuildParmVarDeclForTypedef(DeclContext DC, SourceLocation Loc,
4139	QualType T);
4140	ParmVarDecl CheckParameter(DeclContext DC, SourceLocation StartLoc,
4141	SourceLocation NameLoc,
4142	const IdentifierInfo *Name, QualType T,
4143	TypeSourceInfo *TSInfo, StorageClass SC);
4144
4145	/// Emit diagnostics if the initializer or any of its explicit or
4146	/// implicitly-generated subexpressions require copying or
4147	/// default-initializing a type that is or contains a C union type that is
4148	/// non-trivial to copy or default-initialize.
4149	void checkNonTrivialCUnionInInitializer(const Expr *Init, SourceLocation Loc);
4150
4151	// These flags are passed to checkNonTrivialCUnion.
4152	enum NonTrivialCUnionKind {
4153	NTCUK_Init = `0x1`,
4154	NTCUK_Destruct = `0x2`,
4155	NTCUK_Copy = `0x4`,
4156	};
4157
4158	/// Emit diagnostics if a non-trivial C union type or a struct that contains
4159	/// a non-trivial C union is used in an invalid context.
4160	void checkNonTrivialCUnion(QualType QT, SourceLocation Loc,
4161	NonTrivialCUnionContext UseContext,
4162	unsigned NonTrivialKind);
4163
4164	/// Certain globally-unique variables might be accidentally duplicated if
4165	/// built into multiple shared libraries with hidden visibility. This can
4166	/// cause problems if the variable is mutable, its initialization is
4167	/// effectful, or its address is taken.
4168	bool GloballyUniqueObjectMightBeAccidentallyDuplicated(const VarDecl *Dcl);
4169	void DiagnoseUniqueObjectDuplication(const VarDecl *Dcl);
4170
4171	/// AddInitializerToDecl - Adds the initializer Init to the
4172	/// declaration dcl. If DirectInit is true, this is C++ direct
4173	/// initialization rather than copy initialization.
4174	void AddInitializerToDecl(Decl dcl, Expr init, bool DirectInit);
4175	void ActOnUninitializedDecl(Decl *dcl);
4176
4177	/// ActOnInitializerError - Given that there was an error parsing an
4178	/// initializer for the given declaration, try to at least re-establish
4179	/// invariants such as whether a variable's type is either dependent or
4180	/// complete.
4181	void ActOnInitializerError(Decl *Dcl);
4182
4183	void ActOnCXXForRangeDecl(Decl D, bool* InExpansionStmt);
4184	StmtResult ActOnCXXForRangeIdentifier(Scope *S, SourceLocation IdentLoc,
4185	IdentifierInfo *Ident,
4186	ParsedAttributes &Attrs);
4187
4188	/// Check if VD needs to be dllexport/dllimport due to being in a
4189	/// dllexport/import function.
4190	void CheckStaticLocalForDllExport(VarDecl *VD);
4191	void CheckThreadLocalForLargeAlignment(VarDecl *VD);
4192
4193	/// FinalizeDeclaration - called by ParseDeclarationAfterDeclarator to perform
4194	/// any semantic actions necessary after any initializer has been attached.
4195	void FinalizeDeclaration(Decl *D);
4196	DeclGroupPtrTy FinalizeDeclaratorGroup(Scope S, const* DeclSpec &DS,
4197	ArrayRef<Decl *> Group);
4198
4199	/// BuildDeclaratorGroup - convert a list of declarations into a declaration
4200	/// group, performing any necessary semantic checking.
4201	DeclGroupPtrTy BuildDeclaratorGroup(MutableArrayRef<Decl *> Group);
4202
4203	/// Should be called on all declarations that might have attached
4204	/// documentation comments.
4205	void ActOnDocumentableDecl(Decl *D);
4206	void ActOnDocumentableDecls(ArrayRef<Decl *> Group);
4207
4208	enum class FnBodyKind {
4209	/// C++26 [dcl.fct.def.general]p1
4210	/// function-body:
4211	/// ctor-initializer[opt] compound-statement
4212	/// function-try-block
4213	Other,
4214	/// = default ;
4215	Default,
4216	/// deleted-function-body
4217	///
4218	/// deleted-function-body:
4219	/// = delete ;
4220	/// = delete ( unevaluated-string ) ;
4221	Delete
4222	};
4223
4224	void ActOnFinishKNRParamDeclarations(Scope *S, Declarator &D,
4225	SourceLocation LocAfterDecls);
4226	void CheckForFunctionRedefinition(
4227	FunctionDecl FD, const* FunctionDecl EffectiveDefinition = nullptr*,
4228	SkipBodyInfo SkipBody = nullptr*);
4229	Decl ActOnStartOfFunctionDef(Scope S, Declarator &D,
4230	MultiTemplateParamsArg TemplateParamLists,
4231	SkipBodyInfo SkipBody = nullptr*,
4232	FnBodyKind BodyKind = FnBodyKind::Other);
4233	Decl ActOnStartOfFunctionDef(Scope S, Decl *D,
4234	SkipBodyInfo SkipBody = nullptr*,
4235	FnBodyKind BodyKind = FnBodyKind::Other);
4236	void applyFunctionAttributesBeforeParsingBody(Decl *FD);
4237
4238	/// Determine whether we can delay parsing the body of a function or
4239	/// function template until it is used, assuming we don't care about emitting
4240	/// code for that function.
4241	///
4242	/// This will be \c false if we may need the body of the function in the
4243	/// middle of parsing an expression (where it's impractical to switch to
4244	/// parsing a different function), for instance, if it's constexpr in C++11
4245	/// or has an 'auto' return type in C++14. These cases are essentially bugs.
4246	bool canDelayFunctionBody(const Declarator &D);
4247
4248	/// Determine whether we can skip parsing the body of a function
4249	/// definition, assuming we don't care about analyzing its body or emitting
4250	/// code for that function.
4251	///
4252	/// This will be \c false only if we may need the body of the function in
4253	/// order to parse the rest of the program (for instance, if it is
4254	/// \c constexpr in C++11 or has an 'auto' return type in C++14).
4255	bool canSkipFunctionBody(Decl *D);
4256
4257	/// Given the set of return statements within a function body,
4258	/// compute the variables that are subject to the named return value
4259	/// optimization.
4260	///
4261	/// Each of the variables that is subject to the named return value
4262	/// optimization will be marked as NRVO variables in the AST, and any
4263	/// return statement that has a marked NRVO variable as its NRVO candidate can
4264	/// use the named return value optimization.
4265	///
4266	/// This function applies a very simplistic algorithm for NRVO: if every
4267	/// return statement in the scope of a variable has the same NRVO candidate,
4268	/// that candidate is an NRVO variable.
4269	void computeNRVO(Stmt Body, sema::FunctionScopeInfo Scope);
4270
4271	/// Performs semantic analysis at the end of a function body.
4272	///
4273	/// \param RetainFunctionScopeInfo If \c true, the client is responsible for
4274	/// releasing the associated \p FunctionScopeInfo. This is useful when
4275	/// building e.g. LambdaExprs.
4276	Decl ActOnFinishFunctionBody(Decl Decl, Stmt *Body,
4277	bool IsInstantiation = false,
4278	bool RetainFunctionScopeInfo = false);
4279	Decl ActOnSkippedFunctionBody(Decl Decl);
4280	void ActOnFinishInlineFunctionDef(FunctionDecl *D);
4281
4282	/// ActOnFinishDelayedAttribute - Invoked when we have finished parsing an
4283	/// attribute for which parsing is delayed.
4284	void ActOnFinishDelayedAttribute(Scope S, Decl D, ParsedAttributes &Attrs);
4285
4286	/// Diagnose any unused parameters in the given sequence of
4287	/// ParmVarDecl pointers.
4288	void DiagnoseUnusedParameters(ArrayRef<ParmVarDecl *> Parameters);
4289
4290	/// Diagnose whether the size of parameters or return value of a
4291	/// function or obj-c method definition is pass-by-value and larger than a
4292	/// specified threshold.
4293	void
4294	DiagnoseSizeOfParametersAndReturnValue(ArrayRef<ParmVarDecl *> Parameters,
4295	QualType ReturnTy, NamedDecl *D);
4296
4297	Decl ActOnFileScopeAsmDecl(Expr expr, SourceLocation AsmLoc,
4298	SourceLocation RParenLoc);
4299
4300	TopLevelStmtDecl ActOnStartTopLevelStmtDecl(Scope S);
4301	void ActOnFinishTopLevelStmtDecl(TopLevelStmtDecl D, Stmt Statement);
4302
4303	void ActOnPopScope(SourceLocation Loc, Scope *S);
4304
4305	/// ParsedFreeStandingDeclSpec - This method is invoked when a declspec with
4306	/// no declarator (e.g. "struct foo;") is parsed.
4307	Decl ParsedFreeStandingDeclSpec(Scope S, AccessSpecifier AS, DeclSpec &DS,
4308	const ParsedAttributesView &DeclAttrs,
4309	RecordDecl *&AnonRecord);
4310
4311	/// ParsedFreeStandingDeclSpec - This method is invoked when a declspec with
4312	/// no declarator (e.g. "struct foo;") is parsed. It also accepts template
4313	/// parameters to cope with template friend declarations.
4314	Decl ParsedFreeStandingDeclSpec(Scope S, AccessSpecifier AS, DeclSpec &DS,
4315	const ParsedAttributesView &DeclAttrs,
4316	MultiTemplateParamsArg TemplateParams,
4317	bool IsExplicitInstantiation,
4318	RecordDecl *&AnonRecord,
4319	SourceLocation EllipsisLoc = {});
4320
4321	/// BuildAnonymousStructOrUnion - Handle the declaration of an
4322	/// anonymous structure or union. Anonymous unions are a C++ feature
4323	/// (C++ [class.union]) and a C11 feature; anonymous structures
4324	/// are a C11 feature and GNU C++ extension.
4325	Decl BuildAnonymousStructOrUnion(Scope S, DeclSpec &DS, AccessSpecifier AS,
4326	RecordDecl *Record,
4327	const PrintingPolicy &Policy);
4328
4329	/// Called once it is known whether
4330	/// a tag declaration is an anonymous union or struct.
4331	void ActOnDefinedDeclarationSpecifier(Decl *D);
4332
4333	/// Emit diagnostic warnings for placeholder members.
4334	/// We can only do that after the class is fully constructed,
4335	/// as anonymous union/structs can insert placeholders
4336	/// in their parent scope (which might be a Record).
4337	void DiagPlaceholderFieldDeclDefinitions(RecordDecl *Record);
4338
4339	/// BuildMicrosoftCAnonymousStruct - Handle the declaration of an
4340	/// Microsoft C anonymous structure.
4341	/// Ref: http://msdn.microsoft.com/en-us/library/z2cx9y4f.aspx
4342	/// Example:
4343	///
4344	/// struct A { int a; };
4345	/// struct B { struct A; int b; };
4346	///
4347	/// void foo() {
4348	/// B var;
4349	/// var.a = 3;
4350	/// }
4351	Decl BuildMicrosoftCAnonymousStruct(Scope S, DeclSpec &DS,
4352	RecordDecl *Record);
4353
4354	/// Given a non-tag type declaration, returns an enum useful for indicating
4355	/// what kind of non-tag type this is.
4356	NonTagKind getNonTagTypeDeclKind(const Decl *D, TagTypeKind TTK);
4357
4358	/// Determine whether a tag with a given kind is acceptable
4359	/// as a redeclaration of the given tag declaration.
4360	///
4361	/// \returns true if the new tag kind is acceptable, false otherwise.
4362	bool isAcceptableTagRedeclaration(const TagDecl *Previous, TagTypeKind NewTag,
4363	bool isDefinition, SourceLocation NewTagLoc,
4364	const IdentifierInfo *Name);
4365
4366	/// This is invoked when we see 'struct foo' or 'struct {'. In the
4367	/// former case, Name will be non-null. In the later case, Name will be null.
4368	/// TagSpec indicates what kind of tag this is. TUK indicates whether this is
4369	/// a reference/declaration/definition of a tag.
4370	///
4371	/// \param IsTypeSpecifier \c true if this is a type-specifier (or
4372	/// trailing-type-specifier) other than one in an alias-declaration.
4373	///
4374	/// \param SkipBody If non-null, will be set to indicate if the caller should
4375	/// skip the definition of this tag and treat it as if it were a declaration.
4376	DeclResult ActOnTag(Scope S, unsigned* TagSpec, TagUseKind TUK,
4377	SourceLocation KWLoc, CXXScopeSpec &SS,
4378	IdentifierInfo *Name, SourceLocation NameLoc,
4379	const ParsedAttributesView &Attr, AccessSpecifier AS,
4380	SourceLocation ModulePrivateLoc,
4381	MultiTemplateParamsArg TemplateParameterLists,
4382	bool &OwnedDecl, bool &IsDependent,
4383	SourceLocation ScopedEnumKWLoc,
4384	bool ScopedEnumUsesClassTag, TypeResult UnderlyingType,
4385	bool IsTypeSpecifier, bool IsTemplateParamOrArg,
4386	OffsetOfKind OOK, SkipBodyInfo SkipBody = nullptr*);
4387
4388	/// ActOnField - Each field of a C struct/union is passed into this in order
4389	/// to create a FieldDecl object for it.
4390	Decl ActOnField(Scope S, Decl *TagD, SourceLocation DeclStart,
4391	Declarator &D, Expr *BitfieldWidth);
4392
4393	/// HandleField - Analyze a field of a C struct or a C++ data member.
4394	FieldDecl HandleField(Scope S, RecordDecl *TagD, SourceLocation DeclStart,
4395	Declarator &D, Expr *BitfieldWidth,
4396	InClassInitStyle InitStyle, AccessSpecifier AS);
4397
4398	/// Build a new FieldDecl and check its well-formedness.
4399	///
4400	/// This routine builds a new FieldDecl given the fields name, type,
4401	/// record, etc. \p PrevDecl should refer to any previous declaration
4402	/// with the same name and in the same scope as the field to be
4403	/// created.
4404	///
4405	/// \returns a new FieldDecl.
4406	///
4407	/// \todo The Declarator argument is a hack. It will be removed once
4408	FieldDecl *CheckFieldDecl(DeclarationName Name, QualType T,
4409	TypeSourceInfo TInfo, RecordDecl Record,
4410	SourceLocation Loc, bool Mutable,
4411	Expr *BitfieldWidth, InClassInitStyle InitStyle,
4412	SourceLocation TSSL, AccessSpecifier AS,
4413	NamedDecl PrevDecl, Declarator D = nullptr);
4414
4415	bool CheckNontrivialField(FieldDecl *FD);
4416
4417	/// ActOnLastBitfield - This routine handles synthesized bitfields rules for
4418	/// class and class extensions. For every class \@interface and class
4419	/// extension \@interface, if the last ivar is a bitfield of any type,
4420	/// then add an implicit `char :0` ivar to the end of that interface.
4421	void ActOnLastBitfield(SourceLocation DeclStart,
4422	SmallVectorImpl<Decl *> &AllIvarDecls);
4423
4424	// This is used for both record definitions and ObjC interface declarations.
4425	void ActOnFields(Scope S, SourceLocation RecLoc, Decl TagDecl,
4426	ArrayRef<Decl *> Fields, SourceLocation LBrac,
4427	SourceLocation RBrac, const ParsedAttributesView &AttrList);
4428
4429	/// ActOnTagStartDefinition - Invoked when we have entered the
4430	/// scope of a tag's definition (e.g., for an enumeration, class,
4431	/// struct, or union).
4432	void ActOnTagStartDefinition(Scope S, Decl TagDecl);
4433
4434	/// Perform ODR-like check for C/ObjC when merging tag types from modules.
4435	/// Differently from C++, actually parse the body and reject / error out
4436	/// in case of a structural mismatch.
4437	bool ActOnDuplicateDefinition(Scope S, Decl Prev, SkipBodyInfo &SkipBody);
4438
4439	typedef void *SkippedDefinitionContext;
4440
4441	/// Invoked when we enter a tag definition that we're skipping.
4442	SkippedDefinitionContext ActOnTagStartSkippedDefinition(Scope S, Decl TD);
4443
4444	/// ActOnStartCXXMemberDeclarations - Invoked when we have parsed a
4445	/// C++ record definition's base-specifiers clause and are starting its
4446	/// member declarations.
4447	void ActOnStartCXXMemberDeclarations(Scope S, Decl TagDecl,
4448	SourceLocation FinalLoc,
4449	bool IsFinalSpelledSealed,
4450	bool IsAbstract,
4451	SourceLocation LBraceLoc);
4452
4453	/// ActOnTagFinishDefinition - Invoked once we have finished parsing
4454	/// the definition of a tag (enumeration, class, struct, or union).
4455	void ActOnTagFinishDefinition(Scope S, Decl TagDecl,
4456	SourceRange BraceRange);
4457
4458	ASTContext::CXXRecordDeclRelocationInfo
4459	CheckCXX2CRelocatable(const clang::CXXRecordDecl *D);
4460
4461	void ActOnTagFinishSkippedDefinition(SkippedDefinitionContext Context);
4462
4463	/// ActOnTagDefinitionError - Invoked when there was an unrecoverable
4464	/// error parsing the definition of a tag.
4465	void ActOnTagDefinitionError(Scope S, Decl TagDecl);
4466
4467	EnumConstantDecl CheckEnumConstant(EnumDecl Enum,
4468	EnumConstantDecl *LastEnumConst,
4469	SourceLocation IdLoc, IdentifierInfo *Id,
4470	Expr *val);
4471
4472	/// Check that this is a valid underlying type for an enum declaration.
4473	bool CheckEnumUnderlyingType(TypeSourceInfo *TI);
4474
4475	/// Check whether this is a valid redeclaration of a previous enumeration.
4476	/// \return true if the redeclaration was invalid.
4477	bool CheckEnumRedeclaration(SourceLocation EnumLoc, bool IsScoped,
4478	QualType EnumUnderlyingTy, bool IsFixed,
4479	const EnumDecl *Prev);
4480
4481	/// Determine whether the body of an anonymous enumeration should be skipped.
4482	/// \param II The name of the first enumerator.
4483	SkipBodyInfo shouldSkipAnonEnumBody(Scope S, IdentifierInfo II,
4484	SourceLocation IILoc);
4485
4486	Decl ActOnEnumConstant(Scope S, Decl EnumDecl, Decl LastEnumConstant,
4487	SourceLocation IdLoc, IdentifierInfo *Id,
4488	const ParsedAttributesView &Attrs,
4489	SourceLocation EqualLoc, Expr *Val,
4490	SkipBodyInfo SkipBody = nullptr*);
4491	void ActOnEnumBody(SourceLocation EnumLoc, SourceRange BraceRange,
4492	Decl EnumDecl, ArrayRef<Decl > Elements, Scope *S,
4493	const ParsedAttributesView &Attr);
4494
4495	/// Set the current declaration context until it gets popped.
4496	void PushDeclContext(Scope S, DeclContext DC);
4497	void PopDeclContext();
4498
4499	/// EnterDeclaratorContext - Used when we must lookup names in the context
4500	/// of a declarator's nested name specifier.
4501	void EnterDeclaratorContext(Scope S, DeclContext DC);
4502	void ExitDeclaratorContext(Scope *S);
4503
4504	/// Enter a template parameter scope, after it's been associated with a
4505	/// particular DeclContext. Causes lookup within the scope to chain through
4506	/// enclosing contexts in the correct order.
4507	void EnterTemplatedContext(Scope S, DeclContext DC);
4508
4509	/// Push the parameters of D, which must be a function, into scope.
4510	void ActOnReenterFunctionContext(Scope S, Decl D);
4511	void ActOnExitFunctionContext();
4512
4513	/// Add this decl to the scope shadowed decl chains.
4514	void PushOnScopeChains(NamedDecl D, Scope S, bool AddToContext = true);
4515
4516	/// isDeclInScope - If 'Ctx' is a function/method, isDeclInScope returns true
4517	/// if 'D' is in Scope 'S', otherwise 'S' is ignored and isDeclInScope returns
4518	/// true if 'D' belongs to the given declaration context.
4519	///
4520	/// \param AllowInlineNamespace If \c true, allow the declaration to be in the
4521	/// enclosing namespace set of the context, rather than contained
4522	/// directly within it.
4523	bool isDeclInScope(NamedDecl D, DeclContext Ctx, Scope S = nullptr*,
4524	bool AllowInlineNamespace = false) const;
4525
4526	/// Finds the scope corresponding to the given decl context, if it
4527	/// happens to be an enclosing scope. Otherwise return NULL.
4528	static Scope getScopeForDeclContext(Scope S, DeclContext *DC);
4529
4530	/// Subroutines of ActOnDeclarator().
4531	TypedefDecl ParseTypedefDecl(Scope S, Declarator &D, QualType T,
4532	TypeSourceInfo *TInfo);
4533	bool isIncompatibleTypedef(const TypeDecl Old, TypedefNameDecl New);
4534
4535	/// mergeDeclAttributes - Copy attributes from the Old decl to the New one.
4536	void mergeDeclAttributes(
4537	NamedDecl New, Decl Old,
4538	AvailabilityMergeKind AMK = AvailabilityMergeKind::Redeclaration);
4539
4540	/// CheckAttributesOnDeducedType - Calls Sema functions for attributes that
4541	/// requires the type to be deduced.
4542	void CheckAttributesOnDeducedType(Decl *D);
4543
4544	/// MergeTypedefNameDecl - We just parsed a typedef 'New' which has the
4545	/// same name and scope as a previous declaration 'Old'. Figure out
4546	/// how to resolve this situation, merging decls or emitting
4547	/// diagnostics as appropriate. If there was an error, set New to be invalid.
4548	void MergeTypedefNameDecl(Scope S, TypedefNameDecl New,
4549	LookupResult &OldDecls);
4550
4551	/// CleanupMergedEnum - We have just merged the decl 'New' by making another
4552	/// definition visible.
4553	/// This method performs any necessary cleanup on the parser state to discard
4554	/// child nodes from newly parsed decl we are retiring.
4555	void CleanupMergedEnum(Scope S, Decl New);
4556
4557	/// MergeFunctionDecl - We just parsed a function 'New' from
4558	/// declarator D which has the same name and scope as a previous
4559	/// declaration 'Old'. Figure out how to resolve this situation,
4560	/// merging decls or emitting diagnostics as appropriate.
4561	///
4562	/// In C++, New and Old must be declarations that are not
4563	/// overloaded. Use IsOverload to determine whether New and Old are
4564	/// overloaded, and to select the Old declaration that New should be
4565	/// merged with.
4566	///
4567	/// Returns true if there was an error, false otherwise.
4568	bool MergeFunctionDecl(FunctionDecl New, NamedDecl &Old, Scope *S,
4569	bool MergeTypeWithOld, bool NewDeclIsDefn);
4570
4571	/// Completes the merge of two function declarations that are
4572	/// known to be compatible.
4573	///
4574	/// This routine handles the merging of attributes and other
4575	/// properties of function declarations from the old declaration to
4576	/// the new declaration, once we know that New is in fact a
4577	/// redeclaration of Old.
4578	///
4579	/// \returns false
4580	bool MergeCompatibleFunctionDecls(FunctionDecl New, FunctionDecl Old,
4581	Scope S, bool* MergeTypeWithOld);
4582	void mergeObjCMethodDecls(ObjCMethodDecl New, ObjCMethodDecl Old);
4583
4584	/// MergeVarDecl - We just parsed a variable 'New' which has the same name
4585	/// and scope as a previous declaration 'Old'. Figure out how to resolve this
4586	/// situation, merging decls or emitting diagnostics as appropriate.
4587	///
4588	/// Tentative definition rules (C99 6.9.2p2) are checked by
4589	/// FinalizeDeclaratorGroup. Unfortunately, we can't analyze tentative
4590	/// definitions here, since the initializer hasn't been attached.
4591	void MergeVarDecl(VarDecl *New, LookupResult &Previous);
4592
4593	/// MergeVarDeclTypes - We parsed a variable 'New' which has the same name and
4594	/// scope as a previous declaration 'Old'. Figure out how to merge their
4595	/// types, emitting diagnostics as appropriate.
4596	///
4597	/// Declarations using the auto type specifier (C++ [decl.spec.auto]) call
4598	/// back to here in AddInitializerToDecl. We can't check them before the
4599	/// initializer is attached.
4600	void MergeVarDeclTypes(VarDecl New, VarDecl Old, bool MergeTypeWithOld);
4601
4602	/// We've just determined that \p Old and \p New both appear to be definitions
4603	/// of the same variable. Either diagnose or fix the problem.
4604	bool checkVarDeclRedefinition(VarDecl OldDefn, VarDecl NewDefn);
4605	void notePreviousDefinition(const NamedDecl *Old, SourceLocation New);
4606
4607	/// Filters out lookup results that don't fall within the given scope
4608	/// as determined by isDeclInScope.
4609	void FilterLookupForScope(LookupResult &R, DeclContext Ctx, Scope S,
4610	bool ConsiderLinkage, bool AllowInlineNamespace);
4611
4612	/// We've determined that \p New is a redeclaration of \p Old. Check that they
4613	/// have compatible owning modules.
4614	bool CheckRedeclarationModuleOwnership(NamedDecl New, NamedDecl Old);
4615
4616	/// [module.interface]p6:
4617	/// A redeclaration of an entity X is implicitly exported if X was introduced
4618	/// by an exported declaration; otherwise it shall not be exported.
4619	bool CheckRedeclarationExported(NamedDecl New, NamedDecl Old);
4620
4621	/// A wrapper function for checking the semantic restrictions of
4622	/// a redeclaration within a module.
4623	bool CheckRedeclarationInModule(NamedDecl New, NamedDecl Old);
4624
4625	/// Check the redefinition in C++20 Modules.
4626	///
4627	/// [basic.def.odr]p14:
4628	/// For any definable item D with definitions in multiple translation units,
4629	/// - if D is a non-inline non-templated function or variable, or
4630	/// - if the definitions in different translation units do not satisfy the
4631	/// following requirements,
4632	/// the program is ill-formed; a diagnostic is required only if the
4633	/// definable item is attached to a named module and a prior definition is
4634	/// reachable at the point where a later definition occurs.
4635	/// - Each such definition shall not be attached to a named module
4636	/// ([module.unit]).
4637	/// - Each such definition shall consist of the same sequence of tokens, ...
4638	/// ...
4639	///
4640	/// Return true if the redefinition is not allowed. Return false otherwise.
4641	bool IsRedefinitionInModule(const NamedDecl New, const* NamedDecl Old) const*;
4642
4643	bool ShouldWarnIfUnusedFileScopedDecl(const DeclaratorDecl D) const*;
4644
4645	/// If it's a file scoped decl that must warn if not used, keep track
4646	/// of it.
4647	void MarkUnusedFileScopedDecl(const DeclaratorDecl *D);
4648
4649	typedef llvm::function_ref<void(SourceLocation Loc, PartialDiagnostic PD)>
4650	DiagReceiverTy;
4651
4652	void DiagnoseUnusedNestedTypedefs(const RecordDecl *D);
4653	void DiagnoseUnusedNestedTypedefs(const RecordDecl *D,
4654	DiagReceiverTy DiagReceiver);
4655	void DiagnoseUnusedDecl(const NamedDecl *ND);
4656
4657	/// DiagnoseUnusedDecl - Emit warnings about declarations that are not used
4658	/// unless they are marked attr(unused).
4659	void DiagnoseUnusedDecl(const NamedDecl *ND, DiagReceiverTy DiagReceiver);
4660
4661	/// If VD is set but not otherwise used, diagnose, for a parameter or a
4662	/// variable.
4663	void DiagnoseUnusedButSetDecl(const VarDecl *VD, DiagReceiverTy DiagReceiver);
4664
4665	/// getNonFieldDeclScope - Retrieves the innermost scope, starting
4666	/// from S, where a non-field would be declared. This routine copes
4667	/// with the difference between C and C++ scoping rules in structs and
4668	/// unions. For example, the following code is well-formed in C but
4669	/// ill-formed in C++:
4670	/// @code
4671	/// struct S6 {
4672	/// enum { BAR } e;
4673	/// };
4674	///
4675	/// void test_S6() {
4676	/// struct S6 a;
4677	/// a.e = BAR;
4678	/// }
4679	/// @endcode
4680	/// For the declaration of BAR, this routine will return a different
4681	/// scope. The scope S will be the scope of the unnamed enumeration
4682	/// within S6. In C++, this routine will return the scope associated
4683	/// with S6, because the enumeration's scope is a transparent
4684	/// context but structures can contain non-field names. In C, this
4685	/// routine will return the translation unit scope, since the
4686	/// enumeration's scope is a transparent context and structures cannot
4687	/// contain non-field names.
4688	Scope getNonFieldDeclScope(Scope S);
4689
4690	FunctionDecl CreateBuiltin(IdentifierInfo II, QualType Type, unsigned ID,
4691	SourceLocation Loc);
4692
4693	/// LazilyCreateBuiltin - The specified Builtin-ID was first used at
4694	/// file scope. lazily create a decl for it. ForRedeclaration is true
4695	/// if we're creating this built-in in anticipation of redeclaring the
4696	/// built-in.
4697	NamedDecl LazilyCreateBuiltin(IdentifierInfo II, unsigned ID, Scope *S,
4698	bool ForRedeclaration, SourceLocation Loc);
4699
4700	/// Get the outermost AttributedType node that sets a calling convention.
4701	/// Valid types should not have multiple attributes with different CCs.
4702	const AttributedType getCallingConvAttributedType(QualType T) const*;
4703
4704	/// GetNameForDeclarator - Determine the full declaration name for the
4705	/// given Declarator.
4706	DeclarationNameInfo GetNameForDeclarator(Declarator &D);
4707
4708	/// Retrieves the declaration name from a parsed unqualified-id.
4709	DeclarationNameInfo GetNameFromUnqualifiedId(const UnqualifiedId &Name);
4710
4711	/// ParsingInitForAutoVars - a set of declarations with auto types for which
4712	/// we are currently parsing the initializer.
4713	llvm::SmallPtrSet<const Decl *, `4`> ParsingInitForAutoVars;
4714
4715	/// Look for a locally scoped extern "C" declaration by the given name.
4716	NamedDecl *findLocallyScopedExternCDecl(DeclarationName Name);
4717
4718	void deduceOpenCLAddressSpace(VarDecl *decl);
4719	void deduceHLSLAddressSpace(VarDecl *decl);
4720
4721	/// Adjust the \c DeclContext for a function or variable that might be a
4722	/// function-local external declaration.
4723	static bool adjustContextForLocalExternDecl(DeclContext *&DC);
4724
4725	void MarkTypoCorrectedFunctionDefinition(const NamedDecl *F);
4726
4727	/// Checks if the variant/multiversion functions are compatible.
4728	bool areMultiversionVariantFunctionsCompatible(
4729	const FunctionDecl OldFD, const* FunctionDecl *NewFD,
4730	const PartialDiagnostic &NoProtoDiagID,
4731	const PartialDiagnosticAt &NoteCausedDiagIDAt,
4732	const PartialDiagnosticAt &NoSupportDiagIDAt,
4733	const PartialDiagnosticAt &DiffDiagIDAt, bool TemplatesSupported,
4734	bool ConstexprSupported, bool CLinkageMayDiffer);
4735
4736	/// type checking declaration initializers (C99 6.7.8)
4737	bool CheckForConstantInitializer(
4738	Expr Init, unsigned* DiagID = diag::err_init_element_not_constant);
4739
4740	QualType deduceVarTypeFromInitializer(VarDecl *VDecl, DeclarationName Name,
4741	QualType Type, TypeSourceInfo *TSI,
4742	SourceRange Range, bool DirectInit,
4743	Expr *Init);
4744
4745	bool DeduceVariableDeclarationType(VarDecl VDecl, bool* DirectInit,
4746	Expr *Init);
4747
4748	sema::LambdaScopeInfo RebuildLambdaScopeInfo(CXXMethodDecl CallOperator);
4749
4750	// Heuristically tells if the function is `get_return_object` member of a
4751	// coroutine promise_type by matching the function name.
4752	static bool CanBeGetReturnObject(const FunctionDecl *FD);
4753	static bool CanBeGetReturnTypeOnAllocFailure(const FunctionDecl *FD);
4754
4755	/// ImplicitlyDefineFunction - An undeclared identifier was used in a function
4756	/// call, forming a call to an implicitly defined function (per C99 6.5.1p2).
4757	NamedDecl *ImplicitlyDefineFunction(SourceLocation Loc, IdentifierInfo &II,
4758	Scope *S);
4759
4760	/// If this function is a C++ replaceable global allocation function
4761	/// (C++2a [basic.stc.dynamic.allocation], C++2a [new.delete]),
4762	/// adds any function attributes that we know a priori based on the standard.
4763	///
4764	/// We need to check for duplicate attributes both here and where user-written
4765	/// attributes are applied to declarations.
4766	void AddKnownFunctionAttributesForReplaceableGlobalAllocationFunction(
4767	FunctionDecl *FD);
4768
4769	/// Adds any function attributes that we know a priori based on
4770	/// the declaration of this function.
4771	///
4772	/// These attributes can apply both to implicitly-declared builtins
4773	/// (like __builtin___printf_chk) or to library-declared functions
4774	/// like NSLog or printf.
4775	///
4776	/// We need to check for duplicate attributes both here and where user-written
4777	/// attributes are applied to declarations.
4778	void AddKnownFunctionAttributes(FunctionDecl *FD);
4779
4780	/// VerifyBitField - verifies that a bit field expression is an ICE and has
4781	/// the correct width, and that the field type is valid.
4782	/// Returns false on success.
4783	ExprResult VerifyBitField(SourceLocation FieldLoc,
4784	const IdentifierInfo *FieldName, QualType FieldTy,
4785	bool IsMsStruct, Expr *BitWidth);
4786
4787	/// IsValueInFlagEnum - Determine if a value is allowed as part of a flag
4788	/// enum. If AllowMask is true, then we also allow the complement of a valid
4789	/// value, to be used as a mask.
4790	bool IsValueInFlagEnum(const EnumDecl ED, const* llvm::APInt &Val,
4791	bool AllowMask) const;
4792
4793	/// ActOnPragmaWeakID - Called on well formed \#pragma weak ident.
4794	void ActOnPragmaWeakID(IdentifierInfo *WeakName, SourceLocation PragmaLoc,
4795	SourceLocation WeakNameLoc);
4796
4797	/// ActOnPragmaRedefineExtname - Called on well formed
4798	/// \#pragma redefine_extname oldname newname.
4799	void ActOnPragmaRedefineExtname(IdentifierInfo *WeakName,
4800	IdentifierInfo *AliasName,
4801	SourceLocation PragmaLoc,
4802	SourceLocation WeakNameLoc,
4803	SourceLocation AliasNameLoc);
4804
4805	/// ActOnPragmaWeakAlias - Called on well formed \#pragma weak ident = ident.
4806	void ActOnPragmaWeakAlias(IdentifierInfo WeakName, IdentifierInfo AliasName,
4807	SourceLocation PragmaLoc,
4808	SourceLocation WeakNameLoc,
4809	SourceLocation AliasNameLoc);
4810
4811	/// Status of the function emission on the CUDA/HIP/OpenMP host/device attrs.
4812	enum class FunctionEmissionStatus {
4813	Emitted,
4814	CUDADiscarded, // Discarded due to CUDA/HIP hostness
4815	OMPDiscarded, // Discarded due to OpenMP hostness
4816	TemplateDiscarded, // Discarded due to uninstantiated templates
4817	Unknown,
4818	};
4819	FunctionEmissionStatus getEmissionStatus(const FunctionDecl *Decl,
4820	bool Final = false);
4821
4822	// Whether the callee should be ignored in CUDA/HIP/OpenMP host/device check.
4823	bool shouldIgnoreInHostDeviceCheck(FunctionDecl *Callee);
4824
4825	/// Function or variable declarations to be checked for whether the deferred
4826	/// diagnostics should be emitted.
4827	llvm::SmallSetVector<Decl *, `4`> DeclsToCheckForDeferredDiags;
4828
4829	private:
4830	/// Map of current shadowing declarations to shadowed declarations. Warn if
4831	/// it looks like the user is trying to modify the shadowing declaration.
4832	llvm::DenseMap<const NamedDecl , const* NamedDecl *> ShadowingDecls;
4833
4834	// We need this to handle
4835	//
4836	// typedef struct {
4837	// void foo() { return 0; }*
4838	// } A;
4839	//
4840	// When we see foo we don't know if after the typedef we will get 'A' or 'A'*
4841	// for example. If 'A', foo will have external linkage. If we have 'A',*
4842	// foo will have no linkage. Since we can't know until we get to the end
4843	// of the typedef, this function finds out if D might have non-external
4844	// linkage. Callers should verify at the end of the TU if it D has external
4845	// linkage or not.
4846	static bool mightHaveNonExternalLinkage(const DeclaratorDecl *FD);
4847
4848	#include "clang/Sema/AttrIsTypeDependent.inc"
4849
4850	///@}
4851
4852	//
4853	//
4854	// -------------------------------------------------------------------------
4855	//
4856	//
4857
4858	/// \name Declaration Attribute Handling
4859	/// Implementations are in SemaDeclAttr.cpp
4860	///@{
4861
4862	public:
4863	/// Describes the kind of priority given to an availability attribute.
4864	///
4865	/// The sum of priorities deteremines the final priority of the attribute.
4866	/// The final priority determines how the attribute will be merged.
4867	/// An attribute with a lower priority will always remove higher priority
4868	/// attributes for the specified platform when it is being applied. An
4869	/// attribute with a higher priority will not be applied if the declaration
4870	/// already has an availability attribute with a lower priority for the
4871	/// specified platform. The final prirority values are not expected to match
4872	/// the values in this enumeration, but instead should be treated as a plain
4873	/// integer value. This enumeration just names the priority weights that are
4874	/// used to calculate that final vaue.
4875	enum AvailabilityPriority : int {
4876	/// The availability attribute was specified explicitly next to the
4877	/// declaration.
4878	AP_Explicit = `0`,
4879
4880	/// The availability attribute was applied using '#pragma clang attribute'.
4881	AP_PragmaClangAttribute = `1`,
4882
4883	/// The availability attribute for a specific platform was inferred from
4884	/// an availability attribute for another platform.
4885	AP_InferredFromOtherPlatform = `2`,
4886
4887	/// The availability attribute was inferred from an 'anyAppleOS'
4888	/// availability attribute.
4889	AP_InferredFromAnyAppleOS = `3`,
4890
4891	/// The availability attribute was inferred from an 'anyAppleOS'
4892	/// availability attribute that was applied using '#pragma clang attribute'.
4893	/// This has the lowest priority.
4894	AP_PragmaClangAttribute_InferredFromAnyAppleOS = `4`
4895	};
4896
4897	/// Describes the reason a calling convention specification was ignored, used
4898	/// for diagnostics.
4899	enum class CallingConventionIgnoredReason {
4900	ForThisTarget = `0`,
4901	VariadicFunction,
4902	ConstructorDestructor,
4903	BuiltinFunction
4904	};
4905
4906	/// A helper function to provide Attribute Location for the Attr types
4907	/// AND the ParsedAttr.
4908	template <typename AttrInfo>
4909	static std::enable_if_t<std::is_base_of_v<Attr, AttrInfo>, SourceLocation>
4910	getAttrLoc(const AttrInfo &AL) {
4911	return AL.getLocation();
4912	}
4913	SourceLocation getAttrLoc(const AttributeCommonInfo &CI);
4914
4915	/// If Expr is a valid integer constant, get the value of the integer
4916	/// expression and return success or failure. May output an error.
4917	///
4918	/// Negative argument is implicitly converted to unsigned, unless
4919	/// \p StrictlyUnsigned is true.
4920	template <typename AttrInfo>
4921	bool checkUInt32Argument(const AttrInfo &AI, const Expr *Expr, uint32_t &Val,
4922	unsigned Idx = UINT_MAX,
4923	bool StrictlyUnsigned = false) {
4924	std::optional<llvm::APSInt> I = llvm::APSInt(`32`);
4925	if (Expr->isTypeDependent() \|\|
4926	!(I = Expr->getIntegerConstantExpr(Ctx: Context))) {
4927	if (Idx != UINT_MAX)
4928	Diag(getAttrLoc(AI), diag::err_attribute_argument_n_type)
4929	<< &AI << Idx << AANT_ArgumentIntegerConstant
4930	<< Expr->getSourceRange();
4931	else
4932	Diag(getAttrLoc(AI), diag::err_attribute_argument_type)
4933	<< &AI << AANT_ArgumentIntegerConstant << Expr->getSourceRange();
4934	return false;
4935	}
4936
4937	if (!I ->isIntN(N: `32`)) {
4938	Diag(Loc: Expr->getExprLoc(), DiagID: diag::err_ice_too_large)
4939	<< toString(I: I, Radix: `10`, Signed: false) << `32` << /* Unsigned / `1`;
4940	return false;
4941	}
4942
4943	if (StrictlyUnsigned && I ->isSigned() && I ->isNegative()) {
4944	Diag(getAttrLoc(AI), diag::err_attribute_requires_positive_integer)
4945	<< &AI << /non-negative/ `1`;
4946	return false;
4947	}
4948
4949	Val = (uint32_t)I ->getZExtValue();
4950	return true;
4951	}
4952
4953	/// WeakTopLevelDecl - Translation-unit scoped declarations generated by
4954	/// \#pragma weak during processing of other Decls.
4955	/// I couldn't figure out a clean way to generate these in-line, so
4956	/// we store them here and handle separately -- which is a hack.
4957	/// It would be best to refactor this.
4958	SmallVector<Decl *, `2`> WeakTopLevelDecl;
4959
4960	/// WeakTopLevelDeclDecls - access to \#pragma weak-generated Decls
4961	SmallVectorImpl<Decl > &WeakTopLevelDecls() { return* WeakTopLevelDecl; }
4962
4963	typedef LazyVector<TypedefNameDecl *, &ExternalSemaSource::ReadExtVectorDecls,
4964	`2`, `2`>
4965	ExtVectorDeclsType;
4966
4967	/// ExtVectorDecls - This is a list all the extended vector types. This allows
4968	/// us to associate a raw vector type with one of the ext_vector type names.
4969	/// This is only necessary for issuing pretty diagnostics.
4970	ExtVectorDeclsType ExtVectorDecls;
4971
4972	/// Check if the argument \p E is a ASCII string literal. If not emit an error
4973	/// and return false, otherwise set \p Str to the value of the string literal
4974	/// and return true.
4975	bool checkStringLiteralArgumentAttr(const AttributeCommonInfo &CI,
4976	const Expr *E, StringRef &Str,
4977	SourceLocation ArgLocation = nullptr*);
4978
4979	/// Check if the argument \p ArgNum of \p Attr is a ASCII string literal.
4980	/// If not emit an error and return false. If the argument is an identifier it
4981	/// will emit an error with a fixit hint and treat it as if it was a string
4982	/// literal.
4983	bool checkStringLiteralArgumentAttr(const ParsedAttr &Attr, unsigned ArgNum,
4984	StringRef &Str,
4985	SourceLocation ArgLocation = nullptr*);
4986
4987	/// Determine if type T is a valid subject for a nonnull and similar
4988	/// attributes. Dependent types are considered valid so they can be checked
4989	/// during instantiation time. By default, we look through references (the
4990	/// behavior used by nonnull), but if the second parameter is true, then we
4991	/// treat a reference type as valid.
4992	bool isValidPointerAttrType(QualType T, bool RefOkay = false);
4993
4994	/// AddAssumeAlignedAttr - Adds an assume_aligned attribute to a particular
4995	/// declaration.
4996	void AddAssumeAlignedAttr(Decl D, const* AttributeCommonInfo &CI, Expr *E,
4997	Expr *OE);
4998
4999	/// AddAllocAlignAttr - Adds an alloc_align attribute to a particular
5000	/// declaration.
5001	void AddAllocAlignAttr(Decl D, const* AttributeCommonInfo &CI,
5002	Expr *ParamExpr);
5003
5004	bool CheckAttrTarget(const ParsedAttr &CurrAttr);
5005	bool CheckAttrNoArgs(const ParsedAttr &CurrAttr);
5006
5007	AvailabilityAttr *
5008	mergeAvailabilityAttr(NamedDecl D, const* AttributeCommonInfo &CI,
5009	const IdentifierInfo Platform, bool* Implicit,
5010	VersionTuple Introduced, VersionTuple Deprecated,
5011	VersionTuple Obsoleted, bool IsUnavailable,
5012	StringRef Message, bool IsStrict, StringRef Replacement,
5013	AvailabilityMergeKind AMK, int Priority,
5014	const IdentifierInfo *IIEnvironment,
5015	const IdentifierInfo InferredPlatformII = nullptr*);
5016
5017	AvailabilityAttr *mergeAndInferAvailabilityAttr(
5018	NamedDecl D, const* AttributeCommonInfo &CI,
5019	const IdentifierInfo Platform, bool* Implicit, VersionTuple Introduced,
5020	VersionTuple Deprecated, VersionTuple Obsoleted, bool IsUnavailable,
5021	StringRef Message, bool IsStrict, StringRef Replacement,
5022	AvailabilityMergeKind AMK, int Priority,
5023	const IdentifierInfo *IIEnvironment,
5024	const IdentifierInfo *InferredPlatformII);
5025
5026	TypeVisibilityAttr *
5027	mergeTypeVisibilityAttr(Decl D, const* AttributeCommonInfo &CI,
5028	TypeVisibilityAttr::VisibilityType Vis);
5029	VisibilityAttr mergeVisibilityAttr(Decl D, const AttributeCommonInfo &CI,
5030	VisibilityAttr::VisibilityType Vis);
5031	void mergeVisibilityType(Decl *D, SourceLocation Loc,
5032	VisibilityAttr::VisibilityType Type);
5033	SectionAttr mergeSectionAttr(Decl D, const AttributeCommonInfo &CI,
5034	StringRef Name);
5035
5036	/// Used to implement to perform semantic checking on
5037	/// attribute((section("foo"))) specifiers.
5038	///
5039	/// In this case, "foo" is passed in to be checked. If the section
5040	/// specifier is invalid, return an Error that indicates the problem.
5041	///
5042	/// This is a simple quality of implementation feature to catch errors
5043	/// and give good diagnostics in cases when the assembler or code generator
5044	/// would otherwise reject the section specifier.
5045	llvm::Error isValidSectionSpecifier(StringRef Str);
5046	bool checkSectionName(SourceLocation LiteralLoc, StringRef Str);
5047	CodeSegAttr mergeCodeSegAttr(Decl D, const AttributeCommonInfo &CI,
5048	StringRef Name);
5049
5050	// Check for things we'd like to warn about. Multiversioning issues are
5051	// handled later in the process, once we know how many exist.
5052	bool checkTargetAttr(SourceLocation LiteralLoc, StringRef Str);
5053
5054	ErrorAttr mergeErrorAttr(Decl D, const AttributeCommonInfo &CI,
5055	StringRef NewUserDiagnostic);
5056	FormatAttr mergeFormatAttr(Decl D, const AttributeCommonInfo &CI,
5057	const IdentifierInfo Format, int* FormatIdx,
5058	int FirstArg);
5059	FormatMatchesAttr mergeFormatMatchesAttr(Decl D,
5060	const AttributeCommonInfo &CI,
5061	const IdentifierInfo *Format,
5062	int FormatIdx,
5063	StringLiteral *FormatStr);
5064	ModularFormatAttr mergeModularFormatAttr(Decl D,
5065	const AttributeCommonInfo &CI,
5066	const IdentifierInfo *ModularImplFn,
5067	StringRef ImplName,
5068	MutableArrayRef<StringRef> Aspects);
5069
5070	PersonalityAttr mergePersonalityAttr(Decl D, FunctionDecl *Routine,
5071	const AttributeCommonInfo &CI);
5072
5073	/// AddAlignedAttr - Adds an aligned attribute to a particular declaration.
5074	void AddAlignedAttr(Decl D, const* AttributeCommonInfo &CI, Expr *E,
5075	bool IsPackExpansion);
5076	void AddAlignedAttr(Decl D, const* AttributeCommonInfo &CI, TypeSourceInfo *T,
5077	bool IsPackExpansion);
5078
5079	/// AddAlignValueAttr - Adds an align_value attribute to a particular
5080	/// declaration.
5081	void AddAlignValueAttr(Decl D, const* AttributeCommonInfo &CI, Expr *E);
5082
5083	/// CreateAnnotationAttr - Creates an annotation Annot with Args arguments.
5084	Attr CreateAnnotationAttr(const* AttributeCommonInfo &CI, StringRef Annot,
5085	MutableArrayRef<Expr *> Args);
5086	Attr CreateAnnotationAttr(const* ParsedAttr &AL);
5087
5088	bool checkMSInheritanceAttrOnDefinition(CXXRecordDecl *RD, SourceRange Range,
5089	bool BestCase,
5090	MSInheritanceModel SemanticSpelling);
5091
5092	void CheckAlignasUnderalignment(Decl *D);
5093
5094	/// AddModeAttr - Adds a mode attribute to a particular declaration.
5095	void AddModeAttr(Decl D, const* AttributeCommonInfo &CI,
5096	const IdentifierInfo Name, bool* InInstantiation = false);
5097	AlwaysInlineAttr mergeAlwaysInlineAttr(Decl D,
5098	const AttributeCommonInfo &CI,
5099	const IdentifierInfo *Ident);
5100	MinSizeAttr mergeMinSizeAttr(Decl D, const AttributeCommonInfo &CI);
5101	OptimizeNoneAttr mergeOptimizeNoneAttr(Decl D,
5102	const AttributeCommonInfo &CI);
5103	InternalLinkageAttr mergeInternalLinkageAttr(Decl D, const ParsedAttr &AL);
5104	InternalLinkageAttr mergeInternalLinkageAttr(Decl D,
5105	const InternalLinkageAttr &AL);
5106
5107	/// Check validaty of calling convention attribute \p attr. If \p FD
5108	/// is not null pointer, use \p FD to determine the CUDA/HIP host/device
5109	/// target. Otherwise, it is specified by \p CFT.
5110	bool CheckCallingConvAttr(
5111	const ParsedAttr &attr, CallingConv &CC, const FunctionDecl FD = nullptr*,
5112	CUDAFunctionTarget CFT = CUDAFunctionTarget::InvalidTarget);
5113
5114	/// Checks a regparm attribute, returning true if it is ill-formed and
5115	/// otherwise setting numParams to the appropriate value.
5116	bool CheckRegparmAttr(const ParsedAttr &attr, unsigned &value);
5117
5118	/// Create a CUDALaunchBoundsAttr attribute. By default, the function only
5119	/// supports nvptx target architectures and skips MaxBlocks if it is previous
5120	/// to sm_90. Use \p IgnoreArch to skip the architecture check.
5121	CUDALaunchBoundsAttr CreateLaunchBoundsAttr(const* AttributeCommonInfo &CI,
5122	Expr *MaxThreads,
5123	Expr MinBlocks, Expr MaxBlocks,
5124	bool IgnoreArch = false);
5125
5126	/// AddLaunchBoundsAttr - Adds a launch_bounds attribute to a particular
5127	/// declaration.
5128	void AddLaunchBoundsAttr(Decl D, const* AttributeCommonInfo &CI,
5129	Expr MaxThreads, Expr MinBlocks, Expr *MaxBlocks);
5130
5131	/// Add a cluster_dims attribute to a particular declaration.
5132	CUDAClusterDimsAttr createClusterDimsAttr(const* AttributeCommonInfo &CI,
5133	Expr X, Expr Y, Expr *Z);
5134	void addClusterDimsAttr(Decl D, const* AttributeCommonInfo &CI, Expr *X,
5135	Expr Y, Expr Z);
5136	/// Add a no_cluster attribute to a particular declaration.
5137	void addNoClusterAttr(Decl D, const* AttributeCommonInfo &CI);
5138
5139	enum class RetainOwnershipKind { NS, CF, OS };
5140
5141	UuidAttr mergeUuidAttr(Decl D, const AttributeCommonInfo &CI,
5142	StringRef UuidAsWritten, MSGuidDecl *GuidDecl);
5143
5144	BTFDeclTagAttr mergeBTFDeclTagAttr(Decl D, const BTFDeclTagAttr &AL);
5145
5146	DLLImportAttr mergeDLLImportAttr(Decl D, const AttributeCommonInfo &CI);
5147	DLLExportAttr mergeDLLExportAttr(Decl D, const AttributeCommonInfo &CI);
5148	MSInheritanceAttr mergeMSInheritanceAttr(Decl D,
5149	const AttributeCommonInfo &CI,
5150	bool BestCase,
5151	MSInheritanceModel Model);
5152
5153	EnforceTCBAttr mergeEnforceTCBAttr(Decl D, const EnforceTCBAttr &AL);
5154	EnforceTCBLeafAttr mergeEnforceTCBLeafAttr(Decl D,
5155	const EnforceTCBLeafAttr &AL);
5156
5157	/// Helper for delayed processing TransparentUnion or
5158	/// BPFPreserveAccessIndexAttr attribute.
5159	void ProcessDeclAttributeDelayed(Decl *D,
5160	const ParsedAttributesView &AttrList);
5161
5162	// Options for ProcessDeclAttributeList().
5163	struct ProcessDeclAttributeOptions {
5164	ProcessDeclAttributeOptions()
5165	: IncludeCXX11Attributes(true), IgnoreTypeAttributes(false) {}
5166
5167	ProcessDeclAttributeOptions WithIncludeCXX11Attributes(bool Val) {
5168	ProcessDeclAttributeOptions Result = *this;
5169	Result.IncludeCXX11Attributes = Val;
5170	return Result;
5171	}
5172
5173	ProcessDeclAttributeOptions WithIgnoreTypeAttributes(bool Val) {
5174	ProcessDeclAttributeOptions Result = *this;
5175	Result.IgnoreTypeAttributes = Val;
5176	return Result;
5177	}
5178
5179	// Should C++11 attributes be processed?
5180	bool IncludeCXX11Attributes;
5181
5182	// Should any type attributes encountered be ignored?
5183	// If this option is false, a diagnostic will be emitted for any type
5184	// attributes of a kind that does not "slide" from the declaration to
5185	// the decl-specifier-seq.
5186	bool IgnoreTypeAttributes;
5187	};
5188
5189	/// ProcessDeclAttributeList - Apply all the decl attributes in the specified
5190	/// attribute list to the specified decl, ignoring any type attributes.
5191	void ProcessDeclAttributeList(Scope S, Decl D,
5192	const ParsedAttributesView &AttrList,
5193	const ProcessDeclAttributeOptions &Options =
5194	ProcessDeclAttributeOptions ());
5195
5196	/// Annotation attributes are the only attributes allowed after an access
5197	/// specifier.
5198	bool ProcessAccessDeclAttributeList(AccessSpecDecl *ASDecl,
5199	const ParsedAttributesView &AttrList);
5200
5201	/// checkUnusedDeclAttributes - Given a declarator which is not being
5202	/// used to build a declaration, complain about any decl attributes
5203	/// which might be lying around on it.
5204	void checkUnusedDeclAttributes(Declarator &D);
5205
5206	void DiagnoseUnknownAttribute(const ParsedAttr &AL);
5207
5208	/// DeclClonePragmaWeak - clone existing decl (maybe definition),
5209	/// \#pragma weak needs a non-definition decl and source may not have one.
5210	NamedDecl DeclClonePragmaWeak(NamedDecl ND, const IdentifierInfo *II,
5211	SourceLocation Loc);
5212
5213	/// DeclApplyPragmaWeak - A declaration (maybe definition) needs \#pragma weak
5214	/// applied to it, possibly with an alias.
5215	void DeclApplyPragmaWeak(Scope S, NamedDecl ND, const WeakInfo &W);
5216
5217	void ProcessPragmaWeak(Scope S, Decl D);
5218	// Decl attributes - this routine is the top level dispatcher.
5219	void ProcessDeclAttributes(Scope S, Decl D, const Declarator &PD);
5220
5221	void PopParsingDeclaration(ParsingDeclState state, Decl *decl);
5222
5223	/// Given a set of delayed diagnostics, re-emit them as if they had
5224	/// been delayed in the current context instead of in the given pool.
5225	/// Essentially, this just moves them to the current pool.
5226	void redelayDiagnostics(sema::DelayedDiagnosticPool &pool);
5227
5228	/// Check that the type is a plain record with one field being a pointer
5229	/// type and the other field being an integer. This matches the common
5230	/// implementation of std::span or sized_allocation_t in P0901R11.
5231	bool CheckSpanLikeType(const AttributeCommonInfo &CI, const QualType &Ty);
5232
5233	/// Check if IdxExpr is a valid parameter index for a function or
5234	/// instance method D. May output an error.
5235	///
5236	/// \returns true if IdxExpr is a valid index.
5237	template <typename AttrInfo>
5238	bool checkFunctionOrMethodParameterIndex(
5239	const Decl D, const* AttrInfo &AI, unsigned AttrArgNum,
5240	const Expr IdxExpr, ParamIdx &Idx, bool* CanIndexImplicitThis = false,
5241	bool CanIndexVariadicArguments = false) {
5242	assert(isFunctionOrMethodOrBlockForAttrSubject(D));
5243
5244	// In C++ the implicit 'this' function parameter also counts.
5245	// Parameters are counted from one.
5246	bool HP = hasFunctionProto(D);
5247	bool HasImplicitThisParam = hasImplicitObjectParameter(D);
5248	bool IV = HP && isFunctionOrMethodVariadic(D);
5249	unsigned NumParams =
5250	(HP ? getFunctionOrMethodNumParams(D) : `0`) + HasImplicitThisParam;
5251
5252	std::optional<llvm::APSInt> IdxInt;
5253	if (IdxExpr->isTypeDependent() \|\|
5254	!(IdxInt = IdxExpr->getIntegerConstantExpr(Ctx: Context))) {
5255	Diag(getAttrLoc(AI), diag::err_attribute_argument_n_type)
5256	<< &AI << AttrArgNum << AANT_ArgumentIntegerConstant
5257	<< IdxExpr->getSourceRange();
5258	return false;
5259	}
5260
5261	constexpr unsigned Limit = `1` << ParamIdx::IdxBitWidth;
5262	unsigned IdxSource = IdxInt ->getLimitedValue(Limit);
5263	if (IdxSource < `1` \|\| IdxSource == Limit \|\|
5264	((!IV \|\| !CanIndexVariadicArguments) && IdxSource > NumParams)) {
5265	Diag(getAttrLoc(AI), diag::err_attribute_argument_out_of_bounds)
5266	<< &AI << AttrArgNum << IdxExpr->getSourceRange();
5267	return false;
5268	}
5269	if (HasImplicitThisParam && !CanIndexImplicitThis) {
5270	if (IdxSource == `1`) {
5271	Diag(getAttrLoc(AI), diag::err_attribute_invalid_implicit_this_argument)
5272	<< &AI << IdxExpr->getSourceRange();
5273	return false;
5274	}
5275	}
5276
5277	Idx = ParamIdx (IdxSource, D);
5278	return true;
5279	}
5280
5281	///@}
5282
5283	//
5284	//
5285	// -------------------------------------------------------------------------
5286	//
5287	//
5288
5289	/// \name C++ Declarations
5290	/// Implementations are in SemaDeclCXX.cpp
5291	///@{
5292
5293	public:
5294	void CheckDelegatingCtorCycles();
5295
5296	/// Called before parsing a function declarator belonging to a function
5297	/// declaration.
5298	void ActOnStartFunctionDeclarationDeclarator(Declarator &D,
5299	unsigned TemplateParameterDepth);
5300
5301	/// Called after parsing a function declarator belonging to a function
5302	/// declaration.
5303	void ActOnFinishFunctionDeclarationDeclarator(Declarator &D);
5304
5305	// Act on C++ namespaces
5306	Decl ActOnStartNamespaceDef(Scope S, SourceLocation InlineLoc,
5307	SourceLocation NamespaceLoc,
5308	SourceLocation IdentLoc, IdentifierInfo *Ident,
5309	SourceLocation LBrace,
5310	const ParsedAttributesView &AttrList,
5311	UsingDirectiveDecl &UsingDecl, bool* IsNested);
5312
5313	/// ActOnFinishNamespaceDef - This callback is called after a namespace is
5314	/// exited. Decl is the DeclTy returned by ActOnStartNamespaceDef.
5315	void ActOnFinishNamespaceDef(Decl *Dcl, SourceLocation RBrace);
5316
5317	NamespaceDecl getStdNamespace() const*;
5318
5319	/// Retrieve the special "std" namespace, which may require us to
5320	/// implicitly define the namespace.
5321	NamespaceDecl *getOrCreateStdNamespace();
5322
5323	CXXRecordDecl getStdBadAlloc() const*;
5324	EnumDecl getStdAlignValT() const*;
5325
5326	TypeAwareAllocationMode ShouldUseTypeAwareOperatorNewOrDelete() const;
5327	FunctionDecl BuildTypeAwareUsualDelete(FunctionTemplateDecl FnDecl,
5328	QualType AllocType, SourceLocation);
5329
5330	ValueDecl tryLookupUnambiguousFieldDecl(RecordDecl ClassDecl,
5331	const IdentifierInfo *MemberOrBase);
5332
5333	enum class ComparisonCategoryUsage {
5334	/// The '<=>' operator was used in an expression and a builtin operator
5335	/// was selected.
5336	OperatorInExpression,
5337	/// A defaulted 'operator<=>' needed the comparison category. This
5338	/// typically only applies to 'std::strong_ordering', due to the implicit
5339	/// fallback return value.
5340	DefaultedOperator,
5341	/// A builtin needed 'std::strong_ordering' (eg. '__builtin_type_order').
5342	Builtin,
5343	};
5344
5345	/// Lookup the specified comparison category types in the standard
5346	/// library, an check the VarDecls possibly returned by the operator<=>
5347	/// builtins for that type.
5348	///
5349	/// \return The type of the comparison category type corresponding to the
5350	/// specified Kind, or a null type if an error occurs
5351	QualType CheckComparisonCategoryType(ComparisonCategoryType Kind,
5352	SourceLocation Loc,
5353	ComparisonCategoryUsage Usage);
5354
5355	/// Tests whether Ty is an instance of std::initializer_list and, if
5356	/// it is and Element is not NULL, assigns the element type to Element.
5357	bool isStdInitializerList(QualType Ty, QualType *Element);
5358
5359	/// Tests whether Ty is an instance of std::type_identity and, if
5360	/// it is and TypeArgument is not NULL, assigns the element type to Element.
5361	/// If MalformedDecl is not null, and type_identity was ruled out due to being
5362	/// incorrectly structured despite having the correct name, the faulty Decl
5363	/// will be assigned to MalformedDecl.
5364	bool isStdTypeIdentity(QualType Ty, QualType *TypeArgument,
5365	const Decl MalformedDecl = nullptr**);
5366
5367	/// Looks for the std::initializer_list template and instantiates it
5368	/// with Element, or emits an error if it's not found.
5369	///
5370	/// \returns The instantiated template, or null on error.
5371	QualType BuildStdInitializerList(QualType Element, SourceLocation Loc);
5372
5373	/// Looks for the std::type_identity template and instantiates it
5374	/// with Type, or returns a null type if type_identity has not been declared
5375	///
5376	/// \returns The instantiated template, or null if std::type_identity is not
5377	/// declared
5378	QualType tryBuildStdTypeIdentity(QualType Type, SourceLocation Loc);
5379
5380	/// Determine whether Ctor is an initializer-list constructor, as
5381	/// defined in [dcl.init.list]p2.
5382	bool isInitListConstructor(const FunctionDecl *Ctor);
5383
5384	Decl ActOnUsingDirective(Scope CurScope, SourceLocation UsingLoc,
5385	SourceLocation NamespcLoc, CXXScopeSpec &SS,
5386	SourceLocation IdentLoc,
5387	IdentifierInfo *NamespcName,
5388	const ParsedAttributesView &AttrList);
5389
5390	void PushUsingDirective(Scope S, UsingDirectiveDecl UDir);
5391
5392	Decl ActOnNamespaceAliasDef(Scope CurScope, SourceLocation NamespaceLoc,
5393	SourceLocation AliasLoc, IdentifierInfo *Alias,
5394	CXXScopeSpec &SS, SourceLocation IdentLoc,
5395	IdentifierInfo *Ident);
5396
5397	/// Remove decls we can't actually see from a lookup being used to declare
5398	/// shadow using decls.
5399	///
5400	/// \param S - The scope of the potential shadow decl
5401	/// \param Previous - The lookup of a potential shadow decl's name.
5402	void FilterUsingLookup(Scope *S, LookupResult &lookup);
5403
5404	/// Hides a using shadow declaration. This is required by the current
5405	/// using-decl implementation when a resolvable using declaration in a
5406	/// class is followed by a declaration which would hide or override
5407	/// one or more of the using decl's targets; for example:
5408	///
5409	/// struct Base { void foo(int); };
5410	/// struct Derived : Base {
5411	/// using Base::foo;
5412	/// void foo(int);
5413	/// };
5414	///
5415	/// The governing language is C++03 [namespace.udecl]p12:
5416	///
5417	/// When a using-declaration brings names from a base class into a
5418	/// derived class scope, member functions in the derived class
5419	/// override and/or hide member functions with the same name and
5420	/// parameter types in a base class (rather than conflicting).
5421	///
5422	/// There are two ways to implement this:
5423	/// (1) optimistically create shadow decls when they're not hidden
5424	/// by existing declarations, or
5425	/// (2) don't create any shadow decls (or at least don't make them
5426	/// visible) until we've fully parsed/instantiated the class.
5427	/// The problem with (1) is that we might have to retroactively remove
5428	/// a shadow decl, which requires several O(n) operations because the
5429	/// decl structures are (very reasonably) not designed for removal.
5430	/// (2) avoids this but is very fiddly and phase-dependent.
5431	void HideUsingShadowDecl(Scope S, UsingShadowDecl Shadow);
5432
5433	/// Determines whether to create a using shadow decl for a particular
5434	/// decl, given the set of decls existing prior to this using lookup.
5435	bool CheckUsingShadowDecl(BaseUsingDecl BUD, NamedDecl Target,
5436	const LookupResult &PreviousDecls,
5437	UsingShadowDecl *&PrevShadow);
5438
5439	/// Builds a shadow declaration corresponding to a 'using' declaration.
5440	UsingShadowDecl BuildUsingShadowDecl(Scope S, BaseUsingDecl *BUD,
5441	NamedDecl *Target,
5442	UsingShadowDecl *PrevDecl);
5443
5444	/// Checks that the given using declaration is not an invalid
5445	/// redeclaration. Note that this is checking only for the using decl
5446	/// itself, not for any ill-formedness among the UsingShadowDecls.
5447	bool CheckUsingDeclRedeclaration(SourceLocation UsingLoc,
5448	bool HasTypenameKeyword,
5449	const CXXScopeSpec &SS,
5450	SourceLocation NameLoc,
5451	const LookupResult &Previous);
5452
5453	/// Checks that the given nested-name qualifier used in a using decl
5454	/// in the current context is appropriately related to the current
5455	/// scope. If an error is found, diagnoses it and returns true.
5456	/// R is nullptr, if the caller has not (yet) done a lookup, otherwise it's
5457	/// the result of that lookup. UD is likewise nullptr, except when we have an
5458	/// already-populated UsingDecl whose shadow decls contain the same
5459	/// information (i.e. we're instantiating a UsingDecl with non-dependent
5460	/// scope).
5461	bool CheckUsingDeclQualifier(SourceLocation UsingLoc, bool HasTypename,
5462	const CXXScopeSpec &SS,
5463	const DeclarationNameInfo &NameInfo,
5464	SourceLocation NameLoc,
5465	const LookupResult R = nullptr*,
5466	const UsingDecl UD = nullptr*);
5467
5468	/// Builds a using declaration.
5469	///
5470	/// \param IsInstantiation - Whether this call arises from an
5471	/// instantiation of an unresolved using declaration. We treat
5472	/// the lookup differently for these declarations.
5473	NamedDecl BuildUsingDeclaration(Scope S, AccessSpecifier AS,
5474	SourceLocation UsingLoc,
5475	bool HasTypenameKeyword,
5476	SourceLocation TypenameLoc, CXXScopeSpec &SS,
5477	DeclarationNameInfo NameInfo,
5478	SourceLocation EllipsisLoc,
5479	const ParsedAttributesView &AttrList,
5480	bool IsInstantiation, bool IsUsingIfExists);
5481	NamedDecl BuildUsingEnumDeclaration(Scope S, AccessSpecifier AS,
5482	SourceLocation UsingLoc,
5483	SourceLocation EnumLoc,
5484	SourceLocation NameLoc,
5485	TypeSourceInfo EnumType, EnumDecl ED);
5486	NamedDecl BuildUsingPackDecl(NamedDecl InstantiatedFrom,
5487	ArrayRef<NamedDecl *> Expansions);
5488
5489	/// Additional checks for a using declaration referring to a constructor name.
5490	bool CheckInheritingConstructorUsingDecl(UsingDecl *UD);
5491
5492	/// Given a derived-class using shadow declaration for a constructor and the
5493	/// correspnding base class constructor, find or create the implicit
5494	/// synthesized derived class constructor to use for this initialization.
5495	CXXConstructorDecl *
5496	findInheritingConstructor(SourceLocation Loc, CXXConstructorDecl *BaseCtor,
5497	ConstructorUsingShadowDecl *DerivedShadow);
5498
5499	Decl ActOnUsingDeclaration(Scope CurScope, AccessSpecifier AS,
5500	SourceLocation UsingLoc,
5501	SourceLocation TypenameLoc, CXXScopeSpec &SS,
5502	UnqualifiedId &Name, SourceLocation EllipsisLoc,
5503	const ParsedAttributesView &AttrList);
5504	Decl ActOnUsingEnumDeclaration(Scope CurScope, AccessSpecifier AS,
5505	SourceLocation UsingLoc,
5506	SourceLocation EnumLoc, SourceRange TyLoc,
5507	const IdentifierInfo &II, ParsedType Ty,
5508	const CXXScopeSpec &SS);
5509	Decl ActOnAliasDeclaration(Scope CurScope, AccessSpecifier AS,
5510	MultiTemplateParamsArg TemplateParams,
5511	SourceLocation UsingLoc, UnqualifiedId &Name,
5512	const ParsedAttributesView &AttrList,
5513	TypeResult Type, Decl *DeclFromDeclSpec);
5514
5515	/// BuildCXXConstructExpr - Creates a complete call to a constructor,
5516	/// including handling of its default argument expressions.
5517	///
5518	/// \param ConstructKind - a CXXConstructExpr::ConstructionKind
5519	ExprResult BuildCXXConstructExpr(
5520	SourceLocation ConstructLoc, QualType DeclInitType, NamedDecl *FoundDecl,
5521	CXXConstructorDecl *Constructor, MultiExprArg Exprs,
5522	bool HadMultipleCandidates, bool IsListInitialization,
5523	bool IsStdInitListInitialization, bool RequiresZeroInit,
5524	CXXConstructionKind ConstructKind, SourceRange ParenRange);
5525
5526	/// Build a CXXConstructExpr whose constructor has already been resolved if
5527	/// it denotes an inherited constructor.
5528	ExprResult BuildCXXConstructExpr(
5529	SourceLocation ConstructLoc, QualType DeclInitType,
5530	CXXConstructorDecl Constructor, bool* Elidable, MultiExprArg Exprs,
5531	bool HadMultipleCandidates, bool IsListInitialization,
5532	bool IsStdInitListInitialization, bool RequiresZeroInit,
5533	CXXConstructionKind ConstructKind, SourceRange ParenRange);
5534
5535	// FIXME: Can we remove this and have the above BuildCXXConstructExpr check if
5536	// the constructor can be elidable?
5537	ExprResult BuildCXXConstructExpr(
5538	SourceLocation ConstructLoc, QualType DeclInitType, NamedDecl *FoundDecl,
5539	CXXConstructorDecl Constructor, bool* Elidable, MultiExprArg Exprs,
5540	bool HadMultipleCandidates, bool IsListInitialization,
5541	bool IsStdInitListInitialization, bool RequiresZeroInit,
5542	CXXConstructionKind ConstructKind, SourceRange ParenRange);
5543
5544	ExprResult ConvertMemberDefaultInitExpression(FieldDecl FD, Expr InitExpr,
5545	SourceLocation InitLoc);
5546
5547	/// FinalizeVarWithDestructor - Prepare for calling destructor on the
5548	/// constructed variable.
5549	void FinalizeVarWithDestructor(VarDecl VD, CXXRecordDecl DeclInit);
5550
5551	/// Helper class that collects exception specifications for
5552	/// implicitly-declared special member functions.
5553	class ImplicitExceptionSpecification {
5554	// Pointer to allow copying
5555	Sema *Self;
5556	// We order exception specifications thus:
5557	// noexcept is the most restrictive, but is only used in C++11.
5558	// throw() comes next.
5559	// Then a throw(collected exceptions)
5560	// Finally no specification, which is expressed as noexcept(false).
5561	// throw(...) is used instead if any called function uses it.
5562	ExceptionSpecificationType ComputedEST;
5563	llvm::SmallPtrSet<CanQualType, `4`> ExceptionsSeen;
5564	SmallVector<QualType, `4`> Exceptions;
5565
5566	void ClearExceptions() {
5567	ExceptionsSeen.clear();
5568	Exceptions.clear();
5569	}
5570
5571	public:
5572	explicit ImplicitExceptionSpecification(Sema &Self)
5573	: Self(&Self), ComputedEST(EST_BasicNoexcept) {
5574	if (!Self.getLangOpts().CPlusPlus11)
5575	ComputedEST = EST_DynamicNone;
5576	}
5577
5578	/// Get the computed exception specification type.
5579	ExceptionSpecificationType getExceptionSpecType() const {
5580	assert(!isComputedNoexcept(ComputedEST) &&
5581	"noexcept(expr) should not be a possible result");
5582	return ComputedEST;
5583	}
5584
5585	/// The number of exceptions in the exception specification.
5586	unsigned size() const { return Exceptions.size(); }
5587
5588	/// The set of exceptions in the exception specification.
5589	const QualType data() const* { return Exceptions.data(); }
5590
5591	/// Integrate another called method into the collected data.
5592	void CalledDecl(SourceLocation CallLoc, const CXXMethodDecl *Method);
5593
5594	/// Integrate an invoked expression into the collected data.
5595	void CalledExpr(Expr *E) { CalledStmt(S: E); }
5596
5597	/// Integrate an invoked statement into the collected data.
5598	void CalledStmt(Stmt *S);
5599
5600	/// Overwrite an EPI's exception specification with this
5601	/// computed exception specification.
5602	FunctionProtoType::ExceptionSpecInfo getExceptionSpec() const {
5603	FunctionProtoType::ExceptionSpecInfo ESI;
5604	ESI.Type = getExceptionSpecType();
5605	if (ESI.Type == EST_Dynamic) {
5606	ESI.Exceptions = Exceptions;
5607	} else if (ESI.Type == EST_None) {
5608	/// C++11 [except.spec]p14:
5609	/// The exception-specification is noexcept(false) if the set of
5610	/// potential exceptions of the special member function contains "any"
5611	ESI.Type = EST_NoexceptFalse;
5612	ESI.NoexceptExpr =
5613	Self->ActOnCXXBoolLiteral(OpLoc: SourceLocation (), Kind: tok::kw_false).get();
5614	}
5615	return ESI;
5616	}
5617	};
5618
5619	/// Evaluate the implicit exception specification for a defaulted
5620	/// special member function.
5621	void EvaluateImplicitExceptionSpec(SourceLocation Loc, FunctionDecl *FD);
5622
5623	/// Check the given exception-specification and update the
5624	/// exception specification information with the results.
5625	void checkExceptionSpecification(bool IsTopLevel,
5626	ExceptionSpecificationType EST,
5627	ArrayRef<ParsedType> DynamicExceptions,
5628	ArrayRef<SourceRange> DynamicExceptionRanges,
5629	Expr *NoexceptExpr,
5630	SmallVectorImpl<QualType> &Exceptions,
5631	FunctionProtoType::ExceptionSpecInfo &ESI);
5632
5633	/// Add an exception-specification to the given member or friend function
5634	/// (or function template). The exception-specification was parsed
5635	/// after the function itself was declared.
5636	void actOnDelayedExceptionSpecification(
5637	Decl *D, ExceptionSpecificationType EST, SourceRange SpecificationRange,
5638	ArrayRef<ParsedType> DynamicExceptions,
5639	ArrayRef<SourceRange> DynamicExceptionRanges, Expr *NoexceptExpr);
5640
5641	class InheritedConstructorInfo;
5642
5643	/// Determine if a special member function should have a deleted
5644	/// definition when it is defaulted.
5645	bool ShouldDeleteSpecialMember(CXXMethodDecl *MD, CXXSpecialMemberKind CSM,
5646	InheritedConstructorInfo ICI = nullptr*,
5647	bool Diagnose = false);
5648
5649	/// Produce notes explaining why a defaulted function was defined as deleted.
5650	void DiagnoseDeletedDefaultedFunction(FunctionDecl *FD);
5651
5652	/// Declare the implicit default constructor for the given class.
5653	///
5654	/// \param ClassDecl The class declaration into which the implicit
5655	/// default constructor will be added.
5656	///
5657	/// \returns The implicitly-declared default constructor.
5658	CXXConstructorDecl *
5659	DeclareImplicitDefaultConstructor(CXXRecordDecl *ClassDecl);
5660
5661	/// DefineImplicitDefaultConstructor - Checks for feasibility of
5662	/// defining this constructor as the default constructor.
5663	void DefineImplicitDefaultConstructor(SourceLocation CurrentLocation,
5664	CXXConstructorDecl *Constructor);
5665
5666	/// Declare the implicit destructor for the given class.
5667	///
5668	/// \param ClassDecl The class declaration into which the implicit
5669	/// destructor will be added.
5670	///
5671	/// \returns The implicitly-declared destructor.
5672	CXXDestructorDecl DeclareImplicitDestructor(CXXRecordDecl ClassDecl);
5673
5674	/// DefineImplicitDestructor - Checks for feasibility of
5675	/// defining this destructor as the default destructor.
5676	void DefineImplicitDestructor(SourceLocation CurrentLocation,
5677	CXXDestructorDecl *Destructor);
5678
5679	/// Build an exception spec for destructors that don't have one.
5680	///
5681	/// C++11 says that user-defined destructors with no exception spec get one
5682	/// that looks as if the destructor was implicitly declared.
5683	void AdjustDestructorExceptionSpec(CXXDestructorDecl *Destructor);
5684
5685	/// Define the specified inheriting constructor.
5686	void DefineInheritingConstructor(SourceLocation UseLoc,
5687	CXXConstructorDecl *Constructor);
5688
5689	/// Declare the implicit copy constructor for the given class.
5690	///
5691	/// \param ClassDecl The class declaration into which the implicit
5692	/// copy constructor will be added.
5693	///
5694	/// \returns The implicitly-declared copy constructor.
5695	CXXConstructorDecl DeclareImplicitCopyConstructor(CXXRecordDecl ClassDecl);
5696
5697	/// DefineImplicitCopyConstructor - Checks for feasibility of
5698	/// defining this constructor as the copy constructor.
5699	void DefineImplicitCopyConstructor(SourceLocation CurrentLocation,
5700	CXXConstructorDecl *Constructor);
5701
5702	/// Declare the implicit move constructor for the given class.
5703	///
5704	/// \param ClassDecl The Class declaration into which the implicit
5705	/// move constructor will be added.
5706	///
5707	/// \returns The implicitly-declared move constructor, or NULL if it wasn't
5708	/// declared.
5709	CXXConstructorDecl DeclareImplicitMoveConstructor(CXXRecordDecl ClassDecl);
5710
5711	/// DefineImplicitMoveConstructor - Checks for feasibility of
5712	/// defining this constructor as the move constructor.
5713	void DefineImplicitMoveConstructor(SourceLocation CurrentLocation,
5714	CXXConstructorDecl *Constructor);
5715
5716	/// Declare the implicit copy assignment operator for the given class.
5717	///
5718	/// \param ClassDecl The class declaration into which the implicit
5719	/// copy assignment operator will be added.
5720	///
5721	/// \returns The implicitly-declared copy assignment operator.
5722	CXXMethodDecl DeclareImplicitCopyAssignment(CXXRecordDecl ClassDecl);
5723
5724	/// Defines an implicitly-declared copy assignment operator.
5725	void DefineImplicitCopyAssignment(SourceLocation CurrentLocation,
5726	CXXMethodDecl *MethodDecl);
5727
5728	/// Declare the implicit move assignment operator for the given class.
5729	///
5730	/// \param ClassDecl The Class declaration into which the implicit
5731	/// move assignment operator will be added.
5732	///
5733	/// \returns The implicitly-declared move assignment operator, or NULL if it
5734	/// wasn't declared.
5735	CXXMethodDecl DeclareImplicitMoveAssignment(CXXRecordDecl ClassDecl);
5736
5737	/// Defines an implicitly-declared move assignment operator.
5738	void DefineImplicitMoveAssignment(SourceLocation CurrentLocation,
5739	CXXMethodDecl *MethodDecl);
5740
5741	/// Check a completed declaration of an implicit special member.
5742	void CheckImplicitSpecialMemberDeclaration(Scope S, FunctionDecl FD);
5743
5744	/// Determine whether the given function is an implicitly-deleted
5745	/// special member function.
5746	bool isImplicitlyDeleted(FunctionDecl *FD);
5747
5748	/// Check whether 'this' shows up in the type of a static member
5749	/// function after the (naturally empty) cv-qualifier-seq would be.
5750	///
5751	/// \returns true if an error occurred.
5752	bool checkThisInStaticMemberFunctionType(CXXMethodDecl *Method);
5753
5754	/// Whether this' shows up in the exception specification of a static
5755	/// member function.
5756	bool checkThisInStaticMemberFunctionExceptionSpec(CXXMethodDecl *Method);
5757
5758	/// Check whether 'this' shows up in the attributes of the given
5759	/// static member function.
5760	///
5761	/// \returns true if an error occurred.
5762	bool checkThisInStaticMemberFunctionAttributes(CXXMethodDecl *Method);
5763
5764	bool CheckImmediateEscalatingFunctionDefinition(
5765	FunctionDecl FD, const* sema::FunctionScopeInfo *FSI);
5766
5767	void DiagnoseImmediateEscalatingReason(FunctionDecl *FD);
5768
5769	/// Given a constructor and the set of arguments provided for the
5770	/// constructor, convert the arguments and add any required default arguments
5771	/// to form a proper call to this constructor.
5772	///
5773	/// \returns true if an error occurred, false otherwise.
5774	bool CompleteConstructorCall(CXXConstructorDecl *Constructor,
5775	QualType DeclInitType, MultiExprArg ArgsPtr,
5776	SourceLocation Loc,
5777	SmallVectorImpl<Expr *> &ConvertedArgs,
5778	bool AllowExplicit = false,
5779	bool IsListInitialization = false);
5780
5781	/// ActOnCXXEnterDeclInitializer - Invoked when we are about to parse an
5782	/// initializer for the declaration 'Dcl'.
5783	/// After this method is called, according to [C++ 3.4.1p13], if 'Dcl' is a
5784	/// static data member of class X, names should be looked up in the scope of
5785	/// class X.
5786	void ActOnCXXEnterDeclInitializer(Scope S, Decl Dcl);
5787
5788	/// ActOnCXXExitDeclInitializer - Invoked after we are finished parsing an
5789	/// initializer for the declaration 'Dcl'.
5790	void ActOnCXXExitDeclInitializer(Scope S, Decl Dcl);
5791
5792	/// Define the "body" of the conversion from a lambda object to a
5793	/// function pointer.
5794	///
5795	/// This routine doesn't actually define a sensible body; rather, it fills
5796	/// in the initialization expression needed to copy the lambda object into
5797	/// the block, and IR generation actually generates the real body of the
5798	/// block pointer conversion.
5799	void
5800	DefineImplicitLambdaToFunctionPointerConversion(SourceLocation CurrentLoc,
5801	CXXConversionDecl *Conv);
5802
5803	/// Define the "body" of the conversion from a lambda object to a
5804	/// block pointer.
5805	///
5806	/// This routine doesn't actually define a sensible body; rather, it fills
5807	/// in the initialization expression needed to copy the lambda object into
5808	/// the block, and IR generation actually generates the real body of the
5809	/// block pointer conversion.
5810	void DefineImplicitLambdaToBlockPointerConversion(SourceLocation CurrentLoc,
5811	CXXConversionDecl *Conv);
5812
5813	/// ActOnStartLinkageSpecification - Parsed the beginning of a C++
5814	/// linkage specification, including the language and (if present)
5815	/// the '{'. ExternLoc is the location of the 'extern', Lang is the
5816	/// language string literal. LBraceLoc, if valid, provides the location of
5817	/// the '{' brace. Otherwise, this linkage specification does not
5818	/// have any braces.
5819	Decl ActOnStartLinkageSpecification(Scope S, SourceLocation ExternLoc,
5820	Expr *LangStr, SourceLocation LBraceLoc);
5821
5822	/// ActOnFinishLinkageSpecification - Complete the definition of
5823	/// the C++ linkage specification LinkageSpec. If RBraceLoc is
5824	/// valid, it's the position of the closing '}' brace in a linkage
5825	/// specification that uses braces.
5826	Decl ActOnFinishLinkageSpecification(Scope S, Decl *LinkageSpec,
5827	SourceLocation RBraceLoc);
5828
5829	//===--------------------------------------------------------------------===//
5830	// C++ Classes
5831	//
5832
5833	/// Get the class that is directly named by the current context. This is the
5834	/// class for which an unqualified-id in this scope could name a constructor
5835	/// or destructor.
5836	///
5837	/// If the scope specifier denotes a class, this will be that class.
5838	/// If the scope specifier is empty, this will be the class whose
5839	/// member-specification we are currently within. Otherwise, there
5840	/// is no such class.
5841	CXXRecordDecl getCurrentClass(Scope S, const CXXScopeSpec *SS);
5842
5843	/// isCurrentClassName - Determine whether the identifier II is the
5844	/// name of the class type currently being defined. In the case of
5845	/// nested classes, this will only return true if II is the name of
5846	/// the innermost class.
5847	bool isCurrentClassName(const IdentifierInfo &II, Scope *S,
5848	const CXXScopeSpec SS = nullptr*);
5849
5850	/// Determine whether the identifier II is a typo for the name of
5851	/// the class type currently being defined. If so, update it to the identifier
5852	/// that should have been used.
5853	bool isCurrentClassNameTypo(IdentifierInfo &II, const* CXXScopeSpec *SS);
5854
5855	/// ActOnAccessSpecifier - Parsed an access specifier followed by a colon.
5856	bool ActOnAccessSpecifier(AccessSpecifier Access, SourceLocation ASLoc,
5857	SourceLocation ColonLoc,
5858	const ParsedAttributesView &Attrs);
5859
5860	/// ActOnCXXMemberDeclarator - This is invoked when a C++ class member
5861	/// declarator is parsed. 'AS' is the access specifier, 'BW' specifies the
5862	/// bitfield width if there is one, 'InitExpr' specifies the initializer if
5863	/// one has been parsed, and 'InitStyle' is set if an in-class initializer is
5864	/// present (but parsing it has been deferred).
5865	NamedDecl *
5866	ActOnCXXMemberDeclarator(Scope *S, AccessSpecifier AS, Declarator &D,
5867	MultiTemplateParamsArg TemplateParameterLists,
5868	Expr BitfieldWidth, const* VirtSpecifiers &VS,
5869	InClassInitStyle InitStyle);
5870
5871	/// Enter a new C++ default initializer scope. After calling this, the
5872	/// caller must call \ref ActOnFinishCXXInClassMemberInitializer, even if
5873	/// parsing or instantiating the initializer failed.
5874	void ActOnStartCXXInClassMemberInitializer();
5875
5876	/// This is invoked after parsing an in-class initializer for a
5877	/// non-static C++ class member, and after instantiating an in-class
5878	/// initializer in a class template. Such actions are deferred until the class
5879	/// is complete.
5880	void ActOnFinishCXXInClassMemberInitializer(Decl *VarDecl,
5881	SourceLocation EqualLoc,
5882	ExprResult Init);
5883
5884	/// Handle a C++ member initializer using parentheses syntax.
5885	MemInitResult
5886	ActOnMemInitializer(Decl ConstructorD, Scope S, CXXScopeSpec &SS,
5887	IdentifierInfo *MemberOrBase, ParsedType TemplateTypeTy,
5888	const DeclSpec &DS, SourceLocation IdLoc,
5889	SourceLocation LParenLoc, ArrayRef<Expr *> Args,
5890	SourceLocation RParenLoc, SourceLocation EllipsisLoc);
5891
5892	/// Handle a C++ member initializer using braced-init-list syntax.
5893	MemInitResult ActOnMemInitializer(Decl ConstructorD, Scope S,
5894	CXXScopeSpec &SS,
5895	IdentifierInfo *MemberOrBase,
5896	ParsedType TemplateTypeTy,
5897	const DeclSpec &DS, SourceLocation IdLoc,
5898	Expr *InitList, SourceLocation EllipsisLoc);
5899
5900	/// Handle a C++ member initializer.
5901	MemInitResult BuildMemInitializer(Decl ConstructorD, Scope S,
5902	CXXScopeSpec &SS,
5903	IdentifierInfo *MemberOrBase,
5904	ParsedType TemplateTypeTy,
5905	const DeclSpec &DS, SourceLocation IdLoc,
5906	Expr *Init, SourceLocation EllipsisLoc);
5907
5908	MemInitResult BuildMemberInitializer(ValueDecl Member, Expr Init,
5909	SourceLocation IdLoc);
5910
5911	MemInitResult BuildBaseInitializer(QualType BaseType,
5912	TypeSourceInfo BaseTInfo, Expr Init,
5913	CXXRecordDecl *ClassDecl,
5914	SourceLocation EllipsisLoc);
5915
5916	MemInitResult BuildDelegatingInitializer(TypeSourceInfo TInfo, Expr Init,
5917	CXXRecordDecl *ClassDecl);
5918
5919	bool SetDelegatingInitializer(CXXConstructorDecl *Constructor,
5920	CXXCtorInitializer *Initializer);
5921
5922	bool SetCtorInitializers(CXXConstructorDecl Constructor, bool* AnyErrors,
5923	ArrayRef<CXXCtorInitializer *> Initializers = {});
5924
5925	/// MarkBaseAndMemberDestructorsReferenced - Given a record decl,
5926	/// mark all the non-trivial destructors of its members and bases as
5927	/// referenced.
5928	void MarkBaseAndMemberDestructorsReferenced(SourceLocation Loc,
5929	CXXRecordDecl *Record);
5930
5931	/// Mark destructors of virtual bases of this class referenced. In the Itanium
5932	/// C++ ABI, this is done when emitting a destructor for any non-abstract
5933	/// class. In the Microsoft C++ ABI, this is done any time a class's
5934	/// destructor is referenced.
5935	void MarkVirtualBaseDestructorsReferenced(
5936	SourceLocation Location, CXXRecordDecl *ClassDecl,
5937	llvm::SmallPtrSetImpl<const CXXRecordDecl > DirectVirtualBases =
5938	nullptr);
5939
5940	/// Do semantic checks to allow the complete destructor variant to be emitted
5941	/// when the destructor is defined in another translation unit. In the Itanium
5942	/// C++ ABI, destructor variants are emitted together. In the MS C++ ABI, they
5943	/// can be emitted in separate TUs. To emit the complete variant, run a subset
5944	/// of the checks performed when emitting a regular destructor.
5945	void CheckCompleteDestructorVariant(SourceLocation CurrentLocation,
5946	CXXDestructorDecl *Dtor);
5947
5948	/// The list of classes whose vtables have been used within
5949	/// this translation unit, and the source locations at which the
5950	/// first use occurred.
5951	typedef std::pair<CXXRecordDecl *, SourceLocation> VTableUse;
5952
5953	/// The list of vtables that are required but have not yet been
5954	/// materialized.
5955	SmallVector<VTableUse, `16`> VTableUses;
5956
5957	/// The set of classes whose vtables have been used within
5958	/// this translation unit, and a bit that will be true if the vtable is
5959	/// required to be emitted (otherwise, it should be emitted only if needed
5960	/// by code generation).
5961	llvm::DenseMap<CXXRecordDecl , bool*> VTablesUsed;
5962
5963	/// Load any externally-stored vtable uses.
5964	void LoadExternalVTableUses();
5965
5966	/// Note that the vtable for the given class was used at the
5967	/// given location.
5968	void MarkVTableUsed(SourceLocation Loc, CXXRecordDecl *Class,
5969	bool DefinitionRequired = false);
5970
5971	/// Mark the exception specifications of all virtual member functions
5972	/// in the given class as needed.
5973	void MarkVirtualMemberExceptionSpecsNeeded(SourceLocation Loc,
5974	const CXXRecordDecl *RD);
5975
5976	/// MarkVirtualMembersReferenced - Will mark all members of the given
5977	/// CXXRecordDecl referenced.
5978	void MarkVirtualMembersReferenced(SourceLocation Loc, const CXXRecordDecl *RD,
5979	bool ConstexprOnly = false);
5980
5981	/// Define all of the vtables that have been used in this
5982	/// translation unit and reference any virtual members used by those
5983	/// vtables.
5984	///
5985	/// \returns true if any work was done, false otherwise.
5986	bool DefineUsedVTables();
5987
5988	/// AddImplicitlyDeclaredMembersToClass - Adds any implicitly-declared
5989	/// special functions, such as the default constructor, copy
5990	/// constructor, or destructor, to the given C++ class (C++
5991	/// [special]p1). This routine can only be executed just before the
5992	/// definition of the class is complete.
5993	void AddImplicitlyDeclaredMembersToClass(CXXRecordDecl *ClassDecl);
5994
5995	/// ActOnMemInitializers - Handle the member initializers for a constructor.
5996	void ActOnMemInitializers(Decl *ConstructorDecl, SourceLocation ColonLoc,
5997	ArrayRef<CXXCtorInitializer *> MemInits,
5998	bool AnyErrors);
5999
6000	/// Check class-level dllimport/dllexport attribute. The caller must
6001	/// ensure that referenceDLLExportedClassMethods is called some point later
6002	/// when all outer classes of Class are complete.
6003	void checkClassLevelDLLAttribute(CXXRecordDecl *Class);
6004	void checkClassLevelCodeSegAttribute(CXXRecordDecl *Class);
6005
6006	void referenceDLLExportedClassMethods();
6007
6008	/// Perform propagation of DLL attributes from a derived class to a
6009	/// templated base class for MS compatibility.
6010	void propagateDLLAttrToBaseClassTemplate(
6011	CXXRecordDecl Class, Attr ClassAttr,
6012	ClassTemplateSpecializationDecl *BaseTemplateSpec,
6013	SourceLocation BaseLoc);
6014
6015	/// Perform semantic checks on a class definition that has been
6016	/// completing, introducing implicitly-declared members, checking for
6017	/// abstract types, etc.
6018	///
6019	/// \param S The scope in which the class was parsed. Null if we didn't just
6020	/// parse a class definition.
6021	/// \param Record The completed class.
6022	void CheckCompletedCXXClass(Scope S, CXXRecordDecl Record);
6023
6024	/// Check that the C++ class annoated with "trivial_abi" satisfies all the
6025	/// conditions that are needed for the attribute to have an effect.
6026	void checkIllFormedTrivialABIStruct(CXXRecordDecl &RD);
6027
6028	/// Check that VTable Pointer authentication is only being set on the first
6029	/// first instantiation of the vtable
6030	void checkIncorrectVTablePointerAuthenticationAttribute(CXXRecordDecl &RD);
6031
6032	void ActOnFinishCXXMemberSpecification(Scope *S, SourceLocation RLoc,
6033	Decl *TagDecl, SourceLocation LBrac,
6034	SourceLocation RBrac,
6035	const ParsedAttributesView &AttrList);
6036
6037	/// Perform any semantic analysis which needs to be delayed until all
6038	/// pending class member declarations have been parsed.
6039	void ActOnFinishCXXMemberDecls();
6040	void ActOnFinishCXXNonNestedClass();
6041
6042	/// This is used to implement the constant expression evaluation part of the
6043	/// attribute enable_if extension. There is nothing in standard C++ which
6044	/// would require reentering parameters.
6045	void ActOnReenterCXXMethodParameter(Scope S, ParmVarDecl Param);
6046	unsigned ActOnReenterTemplateScope(Decl *Template,
6047	llvm::function_ref<Scope *()> EnterScope);
6048	void ActOnStartDelayedMemberDeclarations(Scope S, Decl Record);
6049
6050	/// ActOnStartDelayedCXXMethodDeclaration - We have completed
6051	/// parsing a top-level (non-nested) C++ class, and we are now
6052	/// parsing those parts of the given Method declaration that could
6053	/// not be parsed earlier (C++ [class.mem]p2), such as default
6054	/// arguments. This action should enter the scope of the given
6055	/// Method declaration as if we had just parsed the qualified method
6056	/// name. However, it should not bring the parameters into scope;
6057	/// that will be performed by ActOnDelayedCXXMethodParameter.
6058	void ActOnStartDelayedCXXMethodDeclaration(Scope S, Decl Method);
6059	void ActOnDelayedCXXMethodParameter(Scope S, Decl Param);
6060	void ActOnFinishDelayedMemberDeclarations(Scope S, Decl Record);
6061
6062	/// ActOnFinishDelayedCXXMethodDeclaration - We have finished
6063	/// processing the delayed method declaration for Method. The method
6064	/// declaration is now considered finished. There may be a separate
6065	/// ActOnStartOfFunctionDef action later (not necessarily
6066	/// immediately!) for this method, if it was also defined inside the
6067	/// class body.
6068	void ActOnFinishDelayedCXXMethodDeclaration(Scope S, Decl Method);
6069	void ActOnFinishDelayedMemberInitializers(Decl *Record);
6070
6071	enum class StringEvaluationContext { StaticAssert = `0`, Asm = `1` };
6072
6073	bool EvaluateAsString(Expr *Message, APValue &Result, ASTContext &Ctx,
6074	StringEvaluationContext EvalContext,
6075	bool ErrorOnInvalidMessage);
6076	bool EvaluateAsString(Expr *Message, std::string &Result, ASTContext &Ctx,
6077	StringEvaluationContext EvalContext,
6078	bool ErrorOnInvalidMessage);
6079
6080	Decl *ActOnStaticAssertDeclaration(SourceLocation StaticAssertLoc,
6081	Expr AssertExpr, Expr AssertMessageExpr,
6082	SourceLocation RParenLoc);
6083	Decl *BuildStaticAssertDeclaration(SourceLocation StaticAssertLoc,
6084	Expr AssertExpr, Expr AssertMessageExpr,
6085	SourceLocation RParenLoc, bool Failed);
6086
6087	/// Try to print more useful information about a failed static_assert
6088	/// with expression \E
6089	void DiagnoseStaticAssertDetails(const Expr *E);
6090
6091	/// If E represents a built-in type trait, or a known standard type trait,
6092	/// try to print more information about why the type type-trait failed.
6093	/// This assumes we already evaluated the expression to a false boolean value.
6094	void DiagnoseTypeTraitDetails(const Expr *E);
6095
6096	/// Handle a friend type declaration. This works in tandem with
6097	/// ActOnTag.
6098	///
6099	/// Notes on friend class templates:
6100	///
6101	/// We generally treat friend class declarations as if they were
6102	/// declaring a class. So, for example, the elaborated type specifier
6103	/// in a friend declaration is required to obey the restrictions of a
6104	/// class-head (i.e. no typedefs in the scope chain), template
6105	/// parameters are required to match up with simple template-ids, &c.
6106	/// However, unlike when declaring a template specialization, it's
6107	/// okay to refer to a template specialization without an empty
6108	/// template parameter declaration, e.g.
6109	/// friend class A<T>::B<unsigned>;
6110	/// We permit this as a special case; if there are any template
6111	/// parameters present at all, require proper matching, i.e.
6112	/// template <> template \<class T> friend class A<int>::B;
6113	Decl ActOnFriendTypeDecl(Scope S, const DeclSpec &DS,
6114	MultiTemplateParamsArg TemplateParams,
6115	SourceLocation EllipsisLoc);
6116	NamedDecl ActOnFriendFunctionDecl(Scope S, Declarator &D,
6117	MultiTemplateParamsArg TemplateParams);
6118
6119	/// CheckConstructorDeclarator - Called by ActOnDeclarator to check
6120	/// the well-formedness of the constructor declarator @p D with type @p
6121	/// R. If there are any errors in the declarator, this routine will
6122	/// emit diagnostics and set the invalid bit to true. In any case, the type
6123	/// will be updated to reflect a well-formed type for the constructor and
6124	/// returned.
6125	QualType CheckConstructorDeclarator(Declarator &D, QualType R,
6126	StorageClass &SC);
6127
6128	/// CheckConstructor - Checks a fully-formed constructor for
6129	/// well-formedness, issuing any diagnostics required. Returns true if
6130	/// the constructor declarator is invalid.
6131	void CheckConstructor(CXXConstructorDecl *Constructor);
6132
6133	/// CheckDestructorDeclarator - Called by ActOnDeclarator to check
6134	/// the well-formednes of the destructor declarator @p D with type @p
6135	/// R. If there are any errors in the declarator, this routine will
6136	/// emit diagnostics and set the declarator to invalid. Even if this happens,
6137	/// will be updated to reflect a well-formed type for the destructor and
6138	/// returned.
6139	QualType CheckDestructorDeclarator(Declarator &D, QualType R,
6140	StorageClass &SC);
6141
6142	/// CheckDestructor - Checks a fully-formed destructor definition for
6143	/// well-formedness, issuing any diagnostics required. Returns true
6144	/// on error.
6145	bool CheckDestructor(CXXDestructorDecl *Destructor);
6146
6147	/// CheckConversionDeclarator - Called by ActOnDeclarator to check the
6148	/// well-formednes of the conversion function declarator @p D with
6149	/// type @p R. If there are any errors in the declarator, this routine
6150	/// will emit diagnostics and return true. Otherwise, it will return
6151	/// false. Either way, the type @p R will be updated to reflect a
6152	/// well-formed type for the conversion operator.
6153	void CheckConversionDeclarator(Declarator &D, QualType &R, StorageClass &SC);
6154
6155	/// ActOnConversionDeclarator - Called by ActOnDeclarator to complete
6156	/// the declaration of the given C++ conversion function. This routine
6157	/// is responsible for recording the conversion function in the C++
6158	/// class, if possible.
6159	Decl ActOnConversionDeclarator(CXXConversionDecl Conversion);
6160
6161	/// Check the validity of a declarator that we parsed for a deduction-guide.
6162	/// These aren't actually declarators in the grammar, so we need to check that
6163	/// the user didn't specify any pieces that are not part of the
6164	/// deduction-guide grammar. Return true on invalid deduction-guide.
6165	bool CheckDeductionGuideDeclarator(Declarator &D, QualType &R,
6166	StorageClass &SC);
6167
6168	void CheckExplicitlyDefaultedFunction(Scope S, FunctionDecl MD);
6169
6170	bool CheckExplicitlyDefaultedSpecialMember(CXXMethodDecl *MD,
6171	CXXSpecialMemberKind CSM,
6172	SourceLocation DefaultLoc);
6173	void CheckDelayedMemberExceptionSpecs();
6174
6175	bool CheckExplicitlyDefaultedComparison(Scope S, FunctionDecl MD,
6176	DefaultedComparisonKind DCK);
6177	void DeclareImplicitEqualityComparison(CXXRecordDecl *RD,
6178	FunctionDecl *Spaceship);
6179	void DefineDefaultedComparison(SourceLocation Loc, FunctionDecl *FD,
6180	DefaultedComparisonKind DCK);
6181
6182	void CheckExplicitObjectMemberFunction(Declarator &D, DeclarationName Name,
6183	QualType R, bool IsLambda,
6184	DeclContext DC = nullptr*);
6185	void CheckExplicitObjectMemberFunction(DeclContext *DC, Declarator &D,
6186	DeclarationName Name, QualType R);
6187	void CheckExplicitObjectLambda(Declarator &D);
6188
6189	//===--------------------------------------------------------------------===//
6190	// C++ Derived Classes
6191	//
6192
6193	/// Check the validity of a C++ base class specifier.
6194	///
6195	/// \returns a new CXXBaseSpecifier if well-formed, emits diagnostics
6196	/// and returns NULL otherwise.
6197	CXXBaseSpecifier CheckBaseSpecifier(CXXRecordDecl Class,
6198	SourceRange SpecifierRange, bool Virtual,
6199	AccessSpecifier Access,
6200	TypeSourceInfo *TInfo,
6201	SourceLocation EllipsisLoc);
6202
6203	/// ActOnBaseSpecifier - Parsed a base specifier. A base specifier is
6204	/// one entry in the base class list of a class specifier, for
6205	/// example:
6206	/// class foo : public bar, virtual private baz {
6207	/// 'public bar' and 'virtual private baz' are each base-specifiers.
6208	BaseResult ActOnBaseSpecifier(Decl *classdecl, SourceRange SpecifierRange,
6209	const ParsedAttributesView &Attrs, bool Virtual,
6210	AccessSpecifier Access, ParsedType basetype,
6211	SourceLocation BaseLoc,
6212	SourceLocation EllipsisLoc);
6213
6214	/// Performs the actual work of attaching the given base class
6215	/// specifiers to a C++ class.
6216	bool AttachBaseSpecifiers(CXXRecordDecl *Class,
6217	MutableArrayRef<CXXBaseSpecifier *> Bases);
6218
6219	/// ActOnBaseSpecifiers - Attach the given base specifiers to the
6220	/// class, after checking whether there are any duplicate base
6221	/// classes.
6222	void ActOnBaseSpecifiers(Decl *ClassDecl,
6223	MutableArrayRef<CXXBaseSpecifier *> Bases);
6224
6225	/// Determine whether the type \p Derived is a C++ class that is
6226	/// derived from the type \p Base.
6227	bool IsDerivedFrom(SourceLocation Loc, CXXRecordDecl *Derived,
6228	CXXRecordDecl *Base, CXXBasePaths &Paths);
6229	bool IsDerivedFrom(SourceLocation Loc, CXXRecordDecl *Derived,
6230	CXXRecordDecl *Base);
6231	bool IsDerivedFrom(SourceLocation Loc, QualType Derived, QualType Base);
6232	bool IsDerivedFrom(SourceLocation Loc, QualType Derived, QualType Base,
6233	CXXBasePaths &Paths);
6234
6235	// FIXME: I don't like this name.
6236	void BuildBasePathArray(const CXXBasePaths &Paths, CXXCastPath &BasePath);
6237
6238	bool CheckDerivedToBaseConversion(QualType Derived, QualType Base,
6239	SourceLocation Loc, SourceRange Range,
6240	CXXCastPath BasePath = nullptr*,
6241	bool IgnoreAccess = false);
6242
6243	/// CheckDerivedToBaseConversion - Check whether the Derived-to-Base
6244	/// conversion (where Derived and Base are class types) is
6245	/// well-formed, meaning that the conversion is unambiguous (and
6246	/// that all of the base classes are accessible). Returns true
6247	/// and emits a diagnostic if the code is ill-formed, returns false
6248	/// otherwise. Loc is the location where this routine should point to
6249	/// if there is an error, and Range is the source range to highlight
6250	/// if there is an error.
6251	///
6252	/// If either InaccessibleBaseID or AmbiguousBaseConvID are 0, then the
6253	/// diagnostic for the respective type of error will be suppressed, but the
6254	/// check for ill-formed code will still be performed.
6255	bool CheckDerivedToBaseConversion(QualType Derived, QualType Base,
6256	unsigned InaccessibleBaseID,
6257	unsigned AmbiguousBaseConvID,
6258	SourceLocation Loc, SourceRange Range,
6259	DeclarationName Name, CXXCastPath *BasePath,
6260	bool IgnoreAccess = false);
6261
6262	/// Builds a string representing ambiguous paths from a
6263	/// specific derived class to different subobjects of the same base
6264	/// class.
6265	///
6266	/// This function builds a string that can be used in error messages
6267	/// to show the different paths that one can take through the
6268	/// inheritance hierarchy to go from the derived class to different
6269	/// subobjects of a base class. The result looks something like this:
6270	/// @code
6271	/// struct D -> struct B -> struct A
6272	/// struct D -> struct C -> struct A
6273	/// @endcode
6274	std::string getAmbiguousPathsDisplayString(CXXBasePaths &Paths);
6275
6276	bool CheckOverridingFunctionAttributes(CXXMethodDecl *New,
6277	const CXXMethodDecl *Old);
6278
6279	/// CheckOverridingFunctionReturnType - Checks whether the return types are
6280	/// covariant, according to C++ [class.virtual]p5.
6281	bool CheckOverridingFunctionReturnType(const CXXMethodDecl *New,
6282	const CXXMethodDecl *Old);
6283
6284	// Check that the overriding method has no explicit object parameter.
6285	bool CheckExplicitObjectOverride(CXXMethodDecl *New,
6286	const CXXMethodDecl *Old);
6287
6288	/// Mark the given method pure.
6289	///
6290	/// \param Method the method to be marked pure.
6291	///
6292	/// \param InitRange the source range that covers the "0" initializer.
6293	bool CheckPureMethod(CXXMethodDecl *Method, SourceRange InitRange);
6294
6295	/// CheckOverrideControl - Check C++11 override control semantics.
6296	void CheckOverrideControl(NamedDecl *D);
6297
6298	/// DiagnoseAbsenceOfOverrideControl - Diagnose if 'override' keyword was
6299	/// not used in the declaration of an overriding method.
6300	void DiagnoseAbsenceOfOverrideControl(NamedDecl D, bool* Inconsistent);
6301
6302	/// CheckIfOverriddenFunctionIsMarkedFinal - Checks whether a virtual member
6303	/// function overrides a virtual member function marked 'final', according to
6304	/// C++11 [class.virtual]p4.
6305	bool CheckIfOverriddenFunctionIsMarkedFinal(const CXXMethodDecl *New,
6306	const CXXMethodDecl *Old);
6307
6308	enum AbstractDiagSelID {
6309	AbstractNone = -`1`,
6310	AbstractReturnType,
6311	AbstractParamType,
6312	AbstractVariableType,
6313	AbstractFieldType,
6314	AbstractIvarType,
6315	AbstractSynthesizedIvarType,
6316	AbstractArrayType
6317	};
6318
6319	struct TypeDiagnoser;
6320
6321	bool isAbstractType(SourceLocation Loc, QualType T);
6322	bool RequireNonAbstractType(SourceLocation Loc, QualType T,
6323	TypeDiagnoser &Diagnoser);
6324	template <typename... Ts>
6325	bool RequireNonAbstractType(SourceLocation Loc, QualType T, unsigned DiagID,
6326	const Ts &...Args) {
6327	BoundTypeDiagnoser<Ts...> Diagnoser(DiagID, Args...);
6328	return RequireNonAbstractType(Loc, T, Diagnoser);
6329	}
6330
6331	void DiagnoseAbstractType(const CXXRecordDecl *RD);
6332
6333	//===--------------------------------------------------------------------===//
6334	// C++ Overloaded Operators [C++ 13.5]
6335	//
6336
6337	/// CheckOverloadedOperatorDeclaration - Check whether the declaration
6338	/// of this overloaded operator is well-formed. If so, returns false;
6339	/// otherwise, emits appropriate diagnostics and returns true.
6340	bool CheckOverloadedOperatorDeclaration(FunctionDecl *FnDecl);
6341
6342	/// CheckLiteralOperatorDeclaration - Check whether the declaration
6343	/// of this literal operator function is well-formed. If so, returns
6344	/// false; otherwise, emits appropriate diagnostics and returns true.
6345	bool CheckLiteralOperatorDeclaration(FunctionDecl *FnDecl);
6346
6347	/// ActOnExplicitBoolSpecifier - Build an ExplicitSpecifier from an expression
6348	/// found in an explicit(bool) specifier.
6349	ExplicitSpecifier ActOnExplicitBoolSpecifier(Expr *E);
6350
6351	/// tryResolveExplicitSpecifier - Attempt to resolve the explict specifier.
6352	/// Returns true if the explicit specifier is now resolved.
6353	bool tryResolveExplicitSpecifier(ExplicitSpecifier &ExplicitSpec);
6354
6355	/// ActOnCXXConditionDeclarationExpr - Parsed a condition declaration of a
6356	/// C++ if/switch/while/for statement.
6357	/// e.g: "if (int x = f()) {...}"
6358	DeclResult ActOnCXXConditionDeclaration(Scope *S, Declarator &D);
6359
6360	// Emitting members of dllexported classes is delayed until the class
6361	// (including field initializers) is fully parsed.
6362	SmallVector<CXXRecordDecl *, `4`> DelayedDllExportClasses;
6363	SmallVector<CXXMethodDecl *, `4`> DelayedDllExportMemberFunctions;
6364
6365	/// Merge the exception specifications of two variable declarations.
6366	///
6367	/// This is called when there's a redeclaration of a VarDecl. The function
6368	/// checks if the redeclaration might have an exception specification and
6369	/// validates compatibility and merges the specs if necessary.
6370	void MergeVarDeclExceptionSpecs(VarDecl New, VarDecl Old);
6371
6372	/// MergeCXXFunctionDecl - Merge two declarations of the same C++
6373	/// function, once we already know that they have the same
6374	/// type. Subroutine of MergeFunctionDecl. Returns true if there was an
6375	/// error, false otherwise.
6376	bool MergeCXXFunctionDecl(FunctionDecl New, FunctionDecl Old, Scope *S);
6377
6378	/// Helpers for dealing with blocks and functions.
6379	void CheckCXXDefaultArguments(FunctionDecl *FD);
6380
6381	/// CheckExtraCXXDefaultArguments - Check for any extra default
6382	/// arguments in the declarator, which is not a function declaration
6383	/// or definition and therefore is not permitted to have default
6384	/// arguments. This routine should be invoked for every declarator
6385	/// that is not a function declaration or definition.
6386	void CheckExtraCXXDefaultArguments(Declarator &D);
6387
6388	/// Perform semantic analysis for the variable declaration that
6389	/// occurs within a C++ catch clause, returning the newly-created
6390	/// variable.
6391	VarDecl BuildExceptionDeclaration(Scope S, TypeSourceInfo *TInfo,
6392	SourceLocation StartLoc,
6393	SourceLocation IdLoc,
6394	const IdentifierInfo *Id);
6395
6396	/// ActOnExceptionDeclarator - Parsed the exception-declarator in a C++ catch
6397	/// handler.
6398	Decl ActOnExceptionDeclarator(Scope S, Declarator &D);
6399
6400	void DiagnoseReturnInConstructorExceptionHandler(CXXTryStmt *TryBlock);
6401
6402	/// Handle a friend tag declaration where the scope specifier was
6403	/// templated.
6404	DeclResult ActOnTemplatedFriendTag(Scope *S, SourceLocation FriendLoc,
6405	unsigned TagSpec, SourceLocation TagLoc,
6406	CXXScopeSpec &SS, IdentifierInfo *Name,
6407	SourceLocation NameLoc,
6408	SourceLocation EllipsisLoc,
6409	const ParsedAttributesView &Attr,
6410	MultiTemplateParamsArg TempParamLists,
6411	TemplateIdAnnotation *TemplateId);
6412
6413	bool CheckDependentFriend(SourceLocation Loc, NestedNameSpecifierLoc NNSLoc,
6414	ArrayRef<TemplateParameterList *> TPLs,
6415	bool IsInstantiation);
6416
6417	bool DiagnosePackIndexingInFriendNNS(SourceLocation Loc,
6418	NestedNameSpecifierLoc NNSLoc);
6419
6420	MSPropertyDecl HandleMSProperty(Scope S, RecordDecl *TagD,
6421	SourceLocation DeclStart, Declarator &D,
6422	Expr *BitfieldWidth,
6423	InClassInitStyle InitStyle,
6424	AccessSpecifier AS,
6425	const ParsedAttr &MSPropertyAttr);
6426
6427	/// Diagnose why the specified class does not have a trivial special member of
6428	/// the given kind.
6429	void DiagnoseNontrivial(const CXXRecordDecl *Record,
6430	CXXSpecialMemberKind CSM);
6431
6432	/// Determine whether a defaulted or deleted special member function is
6433	/// trivial, as specified in C++11 [class.ctor]p5, C++11 [class.copy]p12,
6434	/// C++11 [class.copy]p25, and C++11 [class.dtor]p5.
6435	bool SpecialMemberIsTrivial(
6436	CXXMethodDecl *MD, CXXSpecialMemberKind CSM,
6437	TrivialABIHandling TAH = TrivialABIHandling::IgnoreTrivialABI,
6438	bool Diagnose = false);
6439
6440	/// Handle a C++11 empty-declaration and attribute-declaration.
6441	Decl ActOnEmptyDeclaration(Scope S, const ParsedAttributesView &AttrList,
6442	SourceLocation SemiLoc);
6443
6444	enum class CheckConstexprKind {
6445	/// Diagnose issues that are non-constant or that are extensions.
6446	Diagnose,
6447	/// Identify whether this function satisfies the formal rules for constexpr
6448	/// functions in the current lanugage mode (with no extensions).
6449	CheckValid
6450	};
6451
6452	// Check whether a function declaration satisfies the requirements of a
6453	// constexpr function definition or a constexpr constructor definition. If so,
6454	// return true. If not, produce appropriate diagnostics (unless asked not to
6455	// by Kind) and return false.
6456	//
6457	// This implements C++11 [dcl.constexpr]p3,4, as amended by DR1360.
6458	bool CheckConstexprFunctionDefinition(const FunctionDecl *FD,
6459	CheckConstexprKind Kind);
6460
6461	/// Diagnose methods which overload virtual methods in a base class
6462	/// without overriding any.
6463	void DiagnoseHiddenVirtualMethods(CXXMethodDecl *MD);
6464
6465	/// Check if a method overloads virtual methods in a base class without
6466	/// overriding any.
6467	void
6468	FindHiddenVirtualMethods(CXXMethodDecl *MD,
6469	SmallVectorImpl<CXXMethodDecl *> &OverloadedMethods);
6470	void
6471	NoteHiddenVirtualMethods(CXXMethodDecl *MD,
6472	SmallVectorImpl<CXXMethodDecl *> &OverloadedMethods);
6473
6474	/// ActOnParamDefaultArgument - Check whether the default argument
6475	/// provided for a function parameter is well-formed. If so, attach it
6476	/// to the parameter declaration.
6477	void ActOnParamDefaultArgument(Decl *param, SourceLocation EqualLoc,
6478	Expr *defarg);
6479
6480	/// ActOnParamUnparsedDefaultArgument - We've seen a default
6481	/// argument for a function parameter, but we can't parse it yet
6482	/// because we're inside a class definition. Note that this default
6483	/// argument will be parsed later.
6484	void ActOnParamUnparsedDefaultArgument(Decl *param, SourceLocation EqualLoc,
6485	SourceLocation ArgLoc);
6486
6487	/// ActOnParamDefaultArgumentError - Parsing or semantic analysis of
6488	/// the default argument for the parameter param failed.
6489	void ActOnParamDefaultArgumentError(Decl *param, SourceLocation EqualLoc,
6490	Expr *DefaultArg);
6491	ExprResult ConvertParamDefaultArgument(ParmVarDecl Param, Expr DefaultArg,
6492	SourceLocation EqualLoc);
6493	void SetParamDefaultArgument(ParmVarDecl Param, Expr DefaultArg,
6494	SourceLocation EqualLoc);
6495
6496	void ActOnPureSpecifier(Decl *D, SourceLocation PureSpecLoc);
6497	void SetDeclDeleted(Decl *dcl, SourceLocation DelLoc,
6498	StringLiteral Message = nullptr*);
6499	void SetDeclDefaulted(Decl *dcl, SourceLocation DefaultLoc);
6500
6501	void SetFunctionBodyKind(Decl *D, SourceLocation Loc, FnBodyKind BodyKind,
6502	StringLiteral DeletedMessage = nullptr*);
6503	void ActOnStartTrailingRequiresClause(Scope *S, Declarator &D);
6504	ExprResult ActOnFinishTrailingRequiresClause(ExprResult ConstraintExpr);
6505	ExprResult ActOnRequiresClause(ExprResult ConstraintExpr);
6506
6507	NamedDecl *
6508	ActOnDecompositionDeclarator(Scope *S, Declarator &D,
6509	MultiTemplateParamsArg TemplateParamLists);
6510	void DiagPlaceholderVariableDefinition(SourceLocation Loc);
6511	bool DiagRedefinedPlaceholderFieldDecl(SourceLocation Loc,
6512	RecordDecl *ClassDecl,
6513	const IdentifierInfo *Name);
6514
6515	UnsignedOrNone GetDecompositionElementCount(QualType DecompType,
6516	SourceLocation Loc);
6517	void CheckCompleteDecompositionDeclaration(DecompositionDecl *DD);
6518
6519	/// Stack containing information needed when in C++2a an 'auto' is encountered
6520	/// in a function declaration parameter type specifier in order to invent a
6521	/// corresponding template parameter in the enclosing abbreviated function
6522	/// template. This information is also present in LambdaScopeInfo, stored in
6523	/// the FunctionScopes stack.
6524	SmallVector<InventedTemplateParameterInfo, `4`> InventedParameterInfos;
6525
6526	/// FieldCollector - Collects CXXFieldDecls during parsing of C++ classes.
6527	std::unique_ptr<CXXFieldCollector> FieldCollector;
6528
6529	typedef llvm::SmallSetVector<const NamedDecl *, `16`> NamedDeclSetType;
6530	/// Set containing all declared private fields that are not used.
6531	NamedDeclSetType UnusedPrivateFields;
6532
6533	typedef llvm::SmallPtrSet<const CXXRecordDecl *, `8`> RecordDeclSetTy;
6534
6535	/// PureVirtualClassDiagSet - a set of class declarations which we have
6536	/// emitted a list of pure virtual functions. Used to prevent emitting the
6537	/// same list more than once.
6538	std::unique_ptr<RecordDeclSetTy> PureVirtualClassDiagSet;
6539
6540	typedef LazyVector<CXXConstructorDecl *,
6541	&ExternalSemaSource::ReadDelegatingConstructors, `2`, `2`>
6542	DelegatingCtorDeclsType;
6543
6544	/// All the delegating constructors seen so far in the file, used for
6545	/// cycle detection at the end of the TU.
6546	DelegatingCtorDeclsType DelegatingCtorDecls;
6547
6548	/// The C++ "std" namespace, where the standard library resides.
6549	LazyDeclPtr StdNamespace;
6550
6551	/// The C++ "std::initializer_list" template, which is defined in
6552	/// \<initializer_list>.
6553	ClassTemplateDecl *StdInitializerList;
6554
6555	/// The C++ "std::type_identity" template, which is defined in
6556	/// \<type_traits>.
6557	ClassTemplateDecl *StdTypeIdentity;
6558
6559	// Contains the locations of the beginning of unparsed default
6560	// argument locations.
6561	llvm::DenseMap<ParmVarDecl *, SourceLocation> UnparsedDefaultArgLocs;
6562
6563	/// UndefinedInternals - all the used, undefined objects which require a
6564	/// definition in this translation unit.
6565	llvm::MapVector<NamedDecl *, SourceLocation> UndefinedButUsed;
6566
6567	typedef llvm::PointerIntPair<CXXRecordDecl *, `3`, CXXSpecialMemberKind>
6568	SpecialMemberDecl;
6569
6570	/// The C++ special members which we are currently in the process of
6571	/// declaring. If this process recursively triggers the declaration of the
6572	/// same special member, we should act as if it is not yet declared.
6573	llvm::SmallPtrSet<SpecialMemberDecl, `4`> SpecialMembersBeingDeclared;
6574
6575	void NoteDeletedInheritingConstructor(CXXConstructorDecl *CD);
6576
6577	void ActOnDefaultCtorInitializers(Decl *CDtorDecl);
6578
6579	typedef ProcessingContextState ParsingClassState;
6580	ParsingClassState PushParsingClass() {
6581	ParsingClassDepth++;
6582	return DelayedDiagnostics.pushUndelayed();
6583	}
6584	void PopParsingClass(ParsingClassState state) {
6585	ParsingClassDepth--;
6586	DelayedDiagnostics.popUndelayed(state);
6587	}
6588
6589	ValueDecl tryLookupCtorInitMemberDecl(CXXRecordDecl ClassDecl,
6590	CXXScopeSpec &SS,
6591	ParsedType TemplateTypeTy,
6592	IdentifierInfo *MemberOrBase);
6593
6594	private:
6595	void setupImplicitSpecialMemberType(CXXMethodDecl *SpecialMem,
6596	QualType ResultTy,
6597	ArrayRef<QualType> Args);
6598	// Helper for ActOnFields to check for all function pointer members.
6599	bool EntirelyFunctionPointers(const RecordDecl *Record);
6600
6601	// A cache representing if we've fully checked the various comparison category
6602	// types stored in ASTContext. The bit-index corresponds to the integer value
6603	// of a ComparisonCategoryType enumerator.
6604	llvm::SmallBitVector FullyCheckedComparisonCategories;
6605
6606	/// Check if there is a field shadowing.
6607	void CheckShadowInheritedFields(const SourceLocation &Loc,
6608	DeclarationName FieldName,
6609	const CXXRecordDecl *RD,
6610	bool DeclIsField = true);
6611
6612	///@}
6613
6614	//
6615	//
6616	// -------------------------------------------------------------------------
6617	//
6618	//
6619
6620	/// \name C++ Exception Specifications
6621	/// Implementations are in SemaExceptionSpec.cpp
6622	///@{
6623
6624	public:
6625	/// All the overriding functions seen during a class definition
6626	/// that had their exception spec checks delayed, plus the overridden
6627	/// function.
6628	SmallVector<std::pair<const CXXMethodDecl , const* CXXMethodDecl *>, `2`>
6629	DelayedOverridingExceptionSpecChecks;
6630
6631	/// All the function redeclarations seen during a class definition that had
6632	/// their exception spec checks delayed, plus the prior declaration they
6633	/// should be checked against. Except during error recovery, the new decl
6634	/// should always be a friend declaration, as that's the only valid way to
6635	/// redeclare a special member before its class is complete.
6636	SmallVector<std::pair<FunctionDecl , FunctionDecl >, `2`>
6637	DelayedEquivalentExceptionSpecChecks;
6638
6639	/// Determine if we're in a case where we need to (incorrectly) eagerly
6640	/// parse an exception specification to work around a libstdc++ bug.
6641	bool isLibstdcxxEagerExceptionSpecHack(const Declarator &D);
6642
6643	/// Check the given noexcept-specifier, convert its expression, and compute
6644	/// the appropriate ExceptionSpecificationType.
6645	ExprResult ActOnNoexceptSpec(Expr *NoexceptExpr,
6646	ExceptionSpecificationType &EST);
6647
6648	CanThrowResult canThrow(const Stmt *E);
6649	/// Determine whether the callee of a particular function call can throw.
6650	/// E, D and Loc are all optional.
6651	static CanThrowResult canCalleeThrow(Sema &S, const Expr E, const* Decl *D,
6652	SourceLocation Loc = SourceLocation ());
6653	const FunctionProtoType *ResolveExceptionSpec(SourceLocation Loc,
6654	const FunctionProtoType *FPT);
6655	void UpdateExceptionSpec(FunctionDecl *FD,
6656	const FunctionProtoType::ExceptionSpecInfo &ESI);
6657
6658	/// CheckSpecifiedExceptionType - Check if the given type is valid in an
6659	/// exception specification. Incomplete types, or pointers to incomplete types
6660	/// other than void are not allowed.
6661	///
6662	/// \param[in,out] T The exception type. This will be decayed to a pointer
6663	/// type
6664	/// when the input is an array or a function type.
6665	bool CheckSpecifiedExceptionType(QualType &T, SourceRange Range);
6666
6667	/// CheckDistantExceptionSpec - Check if the given type is a pointer or
6668	/// pointer to member to a function with an exception specification. This
6669	/// means that it is invalid to add another level of indirection.
6670	bool CheckDistantExceptionSpec(QualType T);
6671	bool CheckEquivalentExceptionSpec(FunctionDecl Old, FunctionDecl New);
6672
6673	/// CheckEquivalentExceptionSpec - Check if the two types have equivalent
6674	/// exception specifications. Exception specifications are equivalent if
6675	/// they allow exactly the same set of exception types. It does not matter how
6676	/// that is achieved. See C++ [except.spec]p2.
6677	bool CheckEquivalentExceptionSpec(const FunctionProtoType *Old,
6678	SourceLocation OldLoc,
6679	const FunctionProtoType *New,
6680	SourceLocation NewLoc);
6681	bool CheckEquivalentExceptionSpec(const PartialDiagnostic &DiagID,
6682	const PartialDiagnostic &NoteID,
6683	const FunctionProtoType *Old,
6684	SourceLocation OldLoc,
6685	const FunctionProtoType *New,
6686	SourceLocation NewLoc);
6687	bool handlerCanCatch(QualType HandlerType, QualType ExceptionType);
6688
6689	/// CheckExceptionSpecSubset - Check whether the second function type's
6690	/// exception specification is a subset (or equivalent) of the first function
6691	/// type. This is used by override and pointer assignment checks.
6692	bool CheckExceptionSpecSubset(
6693	const PartialDiagnostic &DiagID, const PartialDiagnostic &NestedDiagID,
6694	const PartialDiagnostic &NoteID, const PartialDiagnostic &NoThrowDiagID,
6695	const FunctionProtoType Superset, bool* SkipSupersetFirstParameter,
6696	SourceLocation SuperLoc, const FunctionProtoType *Subset,
6697	bool SkipSubsetFirstParameter, SourceLocation SubLoc);
6698
6699	/// CheckParamExceptionSpec - Check if the parameter and return types of the
6700	/// two functions have equivalent exception specs. This is part of the
6701	/// assignment and override compatibility check. We do not check the
6702	/// parameters of parameter function pointers recursively, as no sane
6703	/// programmer would even be able to write such a function type.
6704	bool CheckParamExceptionSpec(
6705	const PartialDiagnostic &NestedDiagID, const PartialDiagnostic &NoteID,
6706	const FunctionProtoType Target, bool* SkipTargetFirstParameter,
6707	SourceLocation TargetLoc, const FunctionProtoType *Source,
6708	bool SkipSourceFirstParameter, SourceLocation SourceLoc);
6709
6710	bool CheckExceptionSpecCompatibility(Expr *From, QualType ToType);
6711
6712	/// CheckOverridingFunctionExceptionSpec - Checks whether the exception
6713	/// spec is a subset of base spec.
6714	bool CheckOverridingFunctionExceptionSpec(const CXXMethodDecl *New,
6715	const CXXMethodDecl *Old);
6716
6717	///@}
6718
6719	//
6720	//
6721	// -------------------------------------------------------------------------
6722	//
6723	//
6724
6725	/// \name Expressions
6726	/// Implementations are in SemaExpr.cpp
6727	///@{
6728
6729	public:
6730	/// Describes how the expressions currently being parsed are
6731	/// evaluated at run-time, if at all.
6732	enum class ExpressionEvaluationContext {
6733	/// The current expression and its subexpressions occur within an
6734	/// unevaluated operand (C++11 [expr]p7), such as the subexpression of
6735	/// \c sizeof, where the type of the expression may be significant but
6736	/// no code will be generated to evaluate the value of the expression at
6737	/// run time.
6738	Unevaluated,
6739
6740	/// The current expression occurs within a braced-init-list within
6741	/// an unevaluated operand. This is mostly like a regular unevaluated
6742	/// context, except that we still instantiate constexpr functions that are
6743	/// referenced here so that we can perform narrowing checks correctly.
6744	UnevaluatedList,
6745
6746	/// The current expression occurs within a discarded statement.
6747	/// This behaves largely similarly to an unevaluated operand in preventing
6748	/// definitions from being required, but not in other ways.
6749	DiscardedStatement,
6750
6751	/// The current expression occurs within an unevaluated
6752	/// operand that unconditionally permits abstract references to
6753	/// fields, such as a SIZE operator in MS-style inline assembly.
6754	UnevaluatedAbstract,
6755
6756	/// The current context is "potentially evaluated" in C++11 terms,
6757	/// but the expression is evaluated at compile-time (like the values of
6758	/// cases in a switch statement).
6759	ConstantEvaluated,
6760
6761	/// In addition of being constant evaluated, the current expression
6762	/// occurs in an immediate function context - either a consteval function
6763	/// or a consteval if statement.
6764	ImmediateFunctionContext,
6765
6766	/// The current expression is potentially evaluated at run time,
6767	/// which means that code may be generated to evaluate the value of the
6768	/// expression at run time.
6769	PotentiallyEvaluated,
6770
6771	/// The current expression is potentially evaluated, but any
6772	/// declarations referenced inside that expression are only used if
6773	/// in fact the current expression is used.
6774	///
6775	/// This value is used when parsing default function arguments, for which
6776	/// we would like to provide diagnostics (e.g., passing non-POD arguments
6777	/// through varargs) but do not want to mark declarations as "referenced"
6778	/// until the default argument is used.
6779	PotentiallyEvaluatedIfUsed
6780	};
6781
6782	/// Store a set of either DeclRefExprs or MemberExprs that contain a reference
6783	/// to a variable (constant) that may or may not be odr-used in this Expr, and
6784	/// we won't know until all lvalue-to-rvalue and discarded value conversions
6785	/// have been applied to all subexpressions of the enclosing full expression.
6786	/// This is cleared at the end of each full expression.
6787	using MaybeODRUseExprSet = llvm::SmallSetVector<Expr *, `4`>;
6788	MaybeODRUseExprSet MaybeODRUseExprs;
6789
6790	using ImmediateInvocationCandidate = llvm::PointerIntPair<ConstantExpr *, `1`>;
6791
6792	/// Data structure used to record current or nested
6793	/// expression evaluation contexts.
6794	struct ExpressionEvaluationContextRecord {
6795	/// The expression evaluation context.
6796	ExpressionEvaluationContext Context;
6797
6798	/// Whether the enclosing context needed a cleanup.
6799	CleanupInfo ParentCleanup;
6800
6801	/// The number of active cleanup objects when we entered
6802	/// this expression evaluation context.
6803	unsigned NumCleanupObjects;
6804
6805	MaybeODRUseExprSet SavedMaybeODRUseExprs;
6806
6807	/// The lambdas that are present within this context, if it
6808	/// is indeed an unevaluated context.
6809	SmallVector<LambdaExpr *, `2`> Lambdas;
6810
6811	/// The declaration that provides context for lambda expressions
6812	/// and block literals if the normal declaration context does not
6813	/// suffice, e.g., in a default function argument.
6814	Decl *ManglingContextDecl;
6815
6816	/// Declaration for initializer if one is currently being
6817	/// parsed. Used when an expression has a possibly unreachable
6818	/// diagnostic to reference the declaration as a whole.
6819	VarDecl DeclForInitializer = nullptr*;
6820
6821	/// If we are processing a decltype type, a set of call expressions
6822	/// for which we have deferred checking the completeness of the return type.
6823	SmallVector<CallExpr *, `8`> DelayedDecltypeCalls;
6824
6825	/// If we are processing a decltype type, a set of temporary binding
6826	/// expressions for which we have deferred checking the destructor.
6827	SmallVector<CXXBindTemporaryExpr *, `8`> DelayedDecltypeBinds;
6828
6829	llvm::SmallPtrSet<const Expr *, `8`> PossibleDerefs;
6830
6831	/// Expressions appearing as the LHS of a volatile assignment in this
6832	/// context. We produce a warning for these when popping the context if
6833	/// they are not discarded-value expressions nor unevaluated operands.
6834	SmallVector<Expr *, `2`> VolatileAssignmentLHSs;
6835
6836	/// Set of candidates for starting an immediate invocation.
6837	llvm::SmallVector<ImmediateInvocationCandidate, `4`>
6838	ImmediateInvocationCandidates;
6839
6840	/// Set of DeclRefExprs referencing a consteval function when used in a
6841	/// context not already known to be immediately invoked.
6842	llvm::SmallPtrSet<DeclRefExpr *, `4`> ReferenceToConsteval;
6843
6844	/// P2718R0 - Lifetime extension in range-based for loops.
6845	/// MaterializeTemporaryExprs in for-range-init expressions which need to
6846	/// extend lifetime. Add MaterializeTemporaryExpr if the value of*
6847	/// InLifetimeExtendingContext is true.
6848	SmallVector<MaterializeTemporaryExpr *, `8`> ForRangeLifetimeExtendTemps;
6849
6850	/// Small set of gathered accesses to potentially misaligned members
6851	/// due to the packed attribute.
6852	SmallVector<MisalignedMember, `4`> MisalignedMembers;
6853
6854	/// \brief Describes whether we are in an expression constext which we have
6855	/// to handle differently.
6856	enum ExpressionKind {
6857	EK_Decltype,
6858	EK_TemplateArgument,
6859	EK_AttrArgument,
6860	EK_VariableInit,
6861	EK_Other
6862	} ExprContext;
6863
6864	// A context can be nested in both a discarded statement context and
6865	// an immediate function context, so they need to be tracked independently.
6866	bool InDiscardedStatement;
6867	bool InImmediateFunctionContext;
6868	bool InImmediateEscalatingFunctionContext;
6869
6870	bool IsCurrentlyCheckingDefaultArgumentOrInitializer = false;
6871
6872	// We are in a constant context, but we also allow
6873	// non constant expressions, for example for array bounds (which may be
6874	// VLAs).
6875	bool InConditionallyConstantEvaluateContext = false;
6876
6877	/// Whether we are currently in a context in which all temporaries must be
6878	/// lifetime-extended, even if they're not bound to a reference (for
6879	/// example, in a for-range initializer).
6880	bool InLifetimeExtendingContext = false;
6881
6882	/// Whether evaluating an expression for a switch case label.
6883	bool IsCaseExpr = false;
6884
6885	/// Whether we should rebuild CXXDefaultArgExpr and CXXDefaultInitExpr.
6886	bool RebuildDefaultArgOrDefaultInit = false;
6887
6888	// When evaluating immediate functions in the initializer of a default
6889	// argument or default member initializer, this is the declaration whose
6890	// default initializer is being evaluated and the location of the call
6891	// or constructor definition.
6892	struct InitializationContext {
6893	InitializationContext(SourceLocation Loc, ValueDecl *Decl,
6894	DeclContext *Context)
6895	: Loc (Loc), Decl(Decl), Context(Context) {
6896	assert(Decl && Context && "invalid initialization context");
6897	}
6898
6899	SourceLocation Loc;
6900	ValueDecl Decl = nullptr*;
6901	DeclContext Context = nullptr*;
6902	};
6903	std::optional<InitializationContext> DelayedDefaultInitializationContext;
6904
6905	ExpressionEvaluationContextRecord(ExpressionEvaluationContext Context,
6906	unsigned NumCleanupObjects,
6907	CleanupInfo ParentCleanup,
6908	Decl *ManglingContextDecl,
6909	ExpressionKind ExprContext)
6910	: Context(Context), ParentCleanup (ParentCleanup),
6911	NumCleanupObjects(NumCleanupObjects),
6912	ManglingContextDecl(ManglingContextDecl), ExprContext(ExprContext),
6913	InDiscardedStatement(false), InImmediateFunctionContext(false),
6914	InImmediateEscalatingFunctionContext(false) {}
6915
6916	bool isUnevaluated() const {
6917	return Context == ExpressionEvaluationContext::Unevaluated \|\|
6918	Context == ExpressionEvaluationContext::UnevaluatedAbstract \|\|
6919	Context == ExpressionEvaluationContext::UnevaluatedList;
6920	}
6921
6922	bool isPotentiallyEvaluated() const {
6923	return Context == ExpressionEvaluationContext::PotentiallyEvaluated \|\|
6924	Context ==
6925	ExpressionEvaluationContext::PotentiallyEvaluatedIfUsed \|\|
6926	Context == ExpressionEvaluationContext::ConstantEvaluated;
6927	}
6928
6929	bool isConstantEvaluated() const {
6930	return Context == ExpressionEvaluationContext::ConstantEvaluated \|\|
6931	Context == ExpressionEvaluationContext::ImmediateFunctionContext;
6932	}
6933
6934	bool isImmediateFunctionContext() const {
6935	return Context == ExpressionEvaluationContext::ImmediateFunctionContext \|\|
6936	(Context == ExpressionEvaluationContext::DiscardedStatement &&
6937	InImmediateFunctionContext) \|\|
6938	// C++23 [expr.const]p14:
6939	// An expression or conversion is in an immediate function
6940	// context if it is potentially evaluated and either:
6941	// its innermost enclosing non-block scope is a function*
6942	// parameter scope of an immediate function, or
6943	// its enclosing statement is enclosed by the compound-*
6944	// statement of a consteval if statement.
6945	(Context == ExpressionEvaluationContext::PotentiallyEvaluated &&
6946	InImmediateFunctionContext);
6947	}
6948
6949	bool isDiscardedStatementContext() const {
6950	return Context == ExpressionEvaluationContext::DiscardedStatement \|\|
6951	((Context ==
6952	ExpressionEvaluationContext::ImmediateFunctionContext \|\|
6953	isPotentiallyEvaluated()) &&
6954	InDiscardedStatement);
6955	}
6956	};
6957
6958	const ExpressionEvaluationContextRecord &currentEvaluationContext() const {
6959	assert(!ExprEvalContexts.empty() &&
6960	"Must be in an expression evaluation context");
6961	return ExprEvalContexts.back();
6962	}
6963
6964	ExpressionEvaluationContextRecord &currentEvaluationContext() {
6965	assert(!ExprEvalContexts.empty() &&
6966	"Must be in an expression evaluation context");
6967	return ExprEvalContexts.back();
6968	}
6969
6970	ExpressionEvaluationContextRecord &parentEvaluationContext() {
6971	assert(ExprEvalContexts.size() >= `2` &&
6972	"Must be in an expression evaluation context");
6973	return ExprEvalContexts [ExprEvalContexts.size() - `2`];
6974	}
6975
6976	const ExpressionEvaluationContextRecord &parentEvaluationContext() const {
6977	return const_cast<Sema >(this*)->parentEvaluationContext();
6978	}
6979
6980	bool isAttrContext() const {
6981	return ExprEvalContexts.back().ExprContext ==
6982	ExpressionEvaluationContextRecord::ExpressionKind::EK_AttrArgument;
6983	}
6984
6985	/// Increment when we find a reference; decrement when we find an ignored
6986	/// assignment. Ultimately the value is 0 if every reference is an ignored
6987	/// assignment.
6988	///
6989	/// Uses canonical VarDecl as key so in-class decls and out-of-class defs of
6990	/// static data members get tracked as a single entry.
6991	llvm::DenseMap<const VarDecl , int*> RefsMinusAssignments;
6992
6993	/// Used to control the generation of ExprWithCleanups.
6994	CleanupInfo Cleanup;
6995
6996	/// ExprCleanupObjects - This is the stack of objects requiring
6997	/// cleanup that are created by the current full expression.
6998	SmallVector<ExprWithCleanups::CleanupObject, `8`> ExprCleanupObjects;
6999
7000	/// Determine whether the use of this declaration is valid, without
7001	/// emitting diagnostics.
7002	bool CanUseDecl(NamedDecl D, bool* TreatUnavailableAsInvalid);
7003	// A version of DiagnoseUseOfDecl that should be used if overload resolution
7004	// has been used to find this declaration, which means we don't have to bother
7005	// checking the trailing requires clause.
7006	bool DiagnoseUseOfOverloadedDecl(NamedDecl *D, SourceLocation Loc) {
7007	return DiagnoseUseOfDecl(
7008	D, Locs: Loc, /UnknownObjCClass=/UnknownObjCClass: nullptr, /ObjCPropertyAccess=/ObjCPropertyAccess: false,
7009	/AvoidPartialAvailabilityChecks=/AvoidPartialAvailabilityChecks: false, /ClassReceiver=/ClassReceiver: nullptr,
7010	/SkipTrailingRequiresClause=/SkipTrailingRequiresClause: true);
7011	}
7012
7013	/// Determine whether the use of this declaration is valid, and
7014	/// emit any corresponding diagnostics.
7015	///
7016	/// This routine diagnoses various problems with referencing
7017	/// declarations that can occur when using a declaration. For example,
7018	/// it might warn if a deprecated or unavailable declaration is being
7019	/// used, or produce an error (and return true) if a C++0x deleted
7020	/// function is being used.
7021	///
7022	/// \returns true if there was an error (this declaration cannot be
7023	/// referenced), false otherwise.
7024	bool DiagnoseUseOfDecl(NamedDecl *D, ArrayRef<SourceLocation> Locs,
7025	const ObjCInterfaceDecl UnknownObjCClass = nullptr*,
7026	bool ObjCPropertyAccess = false,
7027	bool AvoidPartialAvailabilityChecks = false,
7028	ObjCInterfaceDecl ClassReceiver = nullptr*,
7029	bool SkipTrailingRequiresClause = false);
7030
7031	/// Emit a note explaining that this function is deleted.
7032	void NoteDeletedFunction(FunctionDecl *FD);
7033
7034	/// DiagnoseSentinelCalls - This routine checks whether a call or
7035	/// message-send is to a declaration with the sentinel attribute, and
7036	/// if so, it checks that the requirements of the sentinel are
7037	/// satisfied.
7038	void DiagnoseSentinelCalls(const NamedDecl *D, SourceLocation Loc,
7039	ArrayRef<Expr *> Args);
7040
7041	void PushExpressionEvaluationContext(
7042	ExpressionEvaluationContext NewContext, Decl LambdaContextDecl = nullptr*,
7043	ExpressionEvaluationContextRecord::ExpressionKind Type =
7044	ExpressionEvaluationContextRecord::EK_Other);
7045
7046	void PushExpressionEvaluationContextForFunction(
7047	ExpressionEvaluationContext NewContext, FunctionDecl *FD);
7048
7049	enum ReuseLambdaContextDecl_t { ReuseLambdaContextDecl };
7050	void PushExpressionEvaluationContext(
7051	ExpressionEvaluationContext NewContext, ReuseLambdaContextDecl_t,
7052	ExpressionEvaluationContextRecord::ExpressionKind Type =
7053	ExpressionEvaluationContextRecord::EK_Other);
7054	void PopExpressionEvaluationContext();
7055
7056	void DiscardCleanupsInEvaluationContext();
7057
7058	ExprResult TransformToPotentiallyEvaluated(Expr *E);
7059	TypeSourceInfo TransformToPotentiallyEvaluated(TypeSourceInfo TInfo);
7060	ExprResult HandleExprEvaluationContextForTypeof(Expr *E);
7061
7062	/// Check whether E, which is either a discarded-value expression or an
7063	/// unevaluated operand, is a simple-assignment to a volatlie-qualified
7064	/// lvalue, and if so, remove it from the list of volatile-qualified
7065	/// assignments that we are going to warn are deprecated.
7066	void CheckUnusedVolatileAssignment(Expr *E);
7067
7068	ExprResult ActOnConstantExpression(ExprResult Res);
7069
7070	// Functions for marking a declaration referenced. These functions also
7071	// contain the relevant logic for marking if a reference to a function or
7072	// variable is an odr-use (in the C++11 sense). There are separate variants
7073	// for expressions referring to a decl; these exist because odr-use marking
7074	// needs to be delayed for some constant variables when we build one of the
7075	// named expressions.
7076	//
7077	// MightBeOdrUse indicates whether the use could possibly be an odr-use, and
7078	// should usually be true. This only needs to be set to false if the lack of
7079	// odr-use cannot be determined from the current context (for instance,
7080	// because the name denotes a virtual function and was written without an
7081	// explicit nested-name-specifier).
7082	void MarkAnyDeclReferenced(SourceLocation Loc, Decl D, bool* MightBeOdrUse);
7083
7084	/// Mark a function referenced, and check whether it is odr-used
7085	/// (C++ [basic.def.odr]p2, C99 6.9p3)
7086	void MarkFunctionReferenced(SourceLocation Loc, FunctionDecl *Func,
7087	bool MightBeOdrUse = true);
7088
7089	/// Mark a variable referenced, and check whether it is odr-used
7090	/// (C++ [basic.def.odr]p2, C99 6.9p3). Note that this should not be
7091	/// used directly for normal expressions referring to VarDecl.
7092	void MarkVariableReferenced(SourceLocation Loc, VarDecl *Var);
7093
7094	/// Perform reference-marking and odr-use handling for a DeclRefExpr.
7095	///
7096	/// Note, this may change the dependence of the DeclRefExpr, and so needs to
7097	/// be handled with care if the DeclRefExpr is not newly-created.
7098	void MarkDeclRefReferenced(DeclRefExpr E, const* Expr Base = nullptr*);
7099
7100	/// Perform reference-marking and odr-use handling for a MemberExpr.
7101	void MarkMemberReferenced(MemberExpr *E);
7102
7103	/// Perform reference-marking and odr-use handling for a FunctionParmPackExpr.
7104	void MarkFunctionParmPackReferenced(FunctionParmPackExpr *E);
7105	void MarkCaptureUsedInEnclosingContext(ValueDecl *Capture, SourceLocation Loc,
7106	unsigned CapturingScopeIndex);
7107
7108	ExprResult CheckLValueToRValueConversionOperand(Expr *E);
7109	void CleanupVarDeclMarking();
7110
7111	/// Try to capture the given variable.
7112	///
7113	/// \param Var The variable to capture.
7114	///
7115	/// \param Loc The location at which the capture occurs.
7116	///
7117	/// \param Kind The kind of capture, which may be implicit (for either a
7118	/// block or a lambda), or explicit by-value or by-reference (for a lambda).
7119	///
7120	/// \param EllipsisLoc The location of the ellipsis, if one is provided in
7121	/// an explicit lambda capture.
7122	///
7123	/// \param BuildAndDiagnose Whether we are actually supposed to add the
7124	/// captures or diagnose errors. If false, this routine merely check whether
7125	/// the capture can occur without performing the capture itself or complaining
7126	/// if the variable cannot be captured.
7127	///
7128	/// \param CaptureType Will be set to the type of the field used to capture
7129	/// this variable in the innermost block or lambda. Only valid when the
7130	/// variable can be captured.
7131	///
7132	/// \param DeclRefType Will be set to the type of a reference to the capture
7133	/// from within the current scope. Only valid when the variable can be
7134	/// captured.
7135	///
7136	/// \param FunctionScopeIndexToStopAt If non-null, it points to the index
7137	/// of the FunctionScopeInfo stack beyond which we do not attempt to capture.
7138	/// This is useful when enclosing lambdas must speculatively capture
7139	/// variables that may or may not be used in certain specializations of
7140	/// a nested generic lambda.
7141	///
7142	/// \returns true if an error occurred (i.e., the variable cannot be
7143	/// captured) and false if the capture succeeded.
7144	bool tryCaptureVariable(ValueDecl *Var, SourceLocation Loc,
7145	TryCaptureKind Kind, SourceLocation EllipsisLoc,
7146	bool BuildAndDiagnose, QualType &CaptureType,
7147	QualType &DeclRefType,
7148	const unsigned *const FunctionScopeIndexToStopAt);
7149
7150	/// Try to capture the given variable.
7151	bool tryCaptureVariable(ValueDecl *Var, SourceLocation Loc,
7152	TryCaptureKind Kind = TryCaptureKind::Implicit,
7153	SourceLocation EllipsisLoc = SourceLocation ());
7154
7155	/// Checks if the variable must be captured.
7156	bool NeedToCaptureVariable(ValueDecl *Var, SourceLocation Loc);
7157
7158	/// Given a variable, determine the type that a reference to that
7159	/// variable will have in the given scope.
7160	QualType getCapturedDeclRefType(ValueDecl *Var, SourceLocation Loc);
7161
7162	/// Mark all of the declarations referenced within a particular AST node as
7163	/// referenced. Used when template instantiation instantiates a non-dependent
7164	/// type -- entities referenced by the type are now referenced.
7165	void MarkDeclarationsReferencedInType(SourceLocation Loc, QualType T);
7166
7167	/// Mark any declarations that appear within this expression or any
7168	/// potentially-evaluated subexpressions as "referenced".
7169	///
7170	/// \param SkipLocalVariables If true, don't mark local variables as
7171	/// 'referenced'.
7172	/// \param StopAt Subexpressions that we shouldn't recurse into.
7173	void MarkDeclarationsReferencedInExpr(Expr *E,
7174	bool SkipLocalVariables = false,
7175	ArrayRef<const Expr *> StopAt = {});
7176
7177	/// Try to convert an expression \p E to type \p Ty. Returns the result of the
7178	/// conversion.
7179	ExprResult tryConvertExprToType(Expr *E, QualType Ty);
7180
7181	/// Conditionally issue a diagnostic based on the statements's reachability
7182	/// analysis.
7183	///
7184	/// \param Stmts If Stmts is non-empty, delay reporting the diagnostic until
7185	/// the function body is parsed, and then do a basic reachability analysis to
7186	/// determine if the statement is reachable. If it is unreachable, the
7187	/// diagnostic will not be emitted.
7188	bool DiagIfReachable(SourceLocation Loc, ArrayRef<const Stmt *> Stmts,
7189	const PartialDiagnostic &PD);
7190
7191	/// Conditionally issue a diagnostic based on the current
7192	/// evaluation context.
7193	///
7194	/// \param Statement If Statement is non-null, delay reporting the
7195	/// diagnostic until the function body is parsed, and then do a basic
7196	/// reachability analysis to determine if the statement is reachable.
7197	/// If it is unreachable, the diagnostic will not be emitted.
7198	bool DiagRuntimeBehavior(SourceLocation Loc, const Stmt *Statement,
7199	const PartialDiagnostic &PD);
7200	/// Similar, but diagnostic is only produced if all the specified statements
7201	/// are reachable.
7202	bool DiagRuntimeBehavior(SourceLocation Loc, ArrayRef<const Stmt *> Stmts,
7203	const PartialDiagnostic &PD);
7204
7205	// Primary Expressions.
7206	SourceRange getExprRange(Expr E) const*;
7207
7208	ExprResult ActOnIdExpression(Scope *S, CXXScopeSpec &SS,
7209	SourceLocation TemplateKWLoc, UnqualifiedId &Id,
7210	bool HasTrailingLParen, bool IsAddressOfOperand,
7211	CorrectionCandidateCallback CCC = nullptr*,
7212	bool IsInlineAsmIdentifier = false);
7213
7214	/// Decomposes the given name into a DeclarationNameInfo, its location, and
7215	/// possibly a list of template arguments.
7216	///
7217	/// If this produces template arguments, it is permitted to call
7218	/// DecomposeTemplateName.
7219	///
7220	/// This actually loses a lot of source location information for
7221	/// non-standard name kinds; we should consider preserving that in
7222	/// some way.
7223	void DecomposeUnqualifiedId(const UnqualifiedId &Id,
7224	TemplateArgumentListInfo &Buffer,
7225	DeclarationNameInfo &NameInfo,
7226	const TemplateArgumentListInfo *&TemplateArgs);
7227
7228	/// Diagnose a lookup that found results in an enclosing class during error
7229	/// recovery. This usually indicates that the results were found in a
7230	/// dependent base class that could not be searched as part of a template
7231	/// definition. Always issues a diagnostic (though this may be only a warning
7232	/// in MS compatibility mode).
7233	///
7234	/// Return \c true if the error is unrecoverable, or \c false if the caller
7235	/// should attempt to recover using these lookup results.
7236	bool DiagnoseDependentMemberLookup(const LookupResult &R);
7237
7238	/// Diagnose an empty lookup.
7239	///
7240	/// \return false if new lookup candidates were found
7241	bool
7242	DiagnoseEmptyLookup(Scope *S, CXXScopeSpec &SS, LookupResult &R,
7243	CorrectionCandidateCallback &CCC,
7244	TemplateArgumentListInfo ExplicitTemplateArgs = nullptr*,
7245	ArrayRef<Expr *> Args = {},
7246	DeclContext LookupCtx = nullptr*);
7247
7248	/// If \p D cannot be odr-used in the current expression evaluation context,
7249	/// return a reason explaining why. Otherwise, return NOUR_None.
7250	NonOdrUseReason getNonOdrUseReasonInCurrentContext(ValueDecl *D);
7251
7252	DeclRefExpr BuildDeclRefExpr(ValueDecl D, QualType Ty, ExprValueKind VK,
7253	SourceLocation Loc,
7254	const CXXScopeSpec SS = nullptr*);
7255	DeclRefExpr *
7256	BuildDeclRefExpr(ValueDecl *D, QualType Ty, ExprValueKind VK,
7257	const DeclarationNameInfo &NameInfo,
7258	const CXXScopeSpec SS = nullptr*,
7259	NamedDecl FoundD = nullptr*,
7260	SourceLocation TemplateKWLoc = SourceLocation (),
7261	const TemplateArgumentListInfo TemplateArgs = nullptr*);
7262
7263	/// BuildDeclRefExpr - Build an expression that references a
7264	/// declaration that does not require a closure capture.
7265	DeclRefExpr *
7266	BuildDeclRefExpr(ValueDecl *D, QualType Ty, ExprValueKind VK,
7267	const DeclarationNameInfo &NameInfo,
7268	NestedNameSpecifierLoc NNS, NamedDecl FoundD = nullptr*,
7269	SourceLocation TemplateKWLoc = SourceLocation (),
7270	const TemplateArgumentListInfo TemplateArgs = nullptr*);
7271
7272	bool UseArgumentDependentLookup(const CXXScopeSpec &SS, const LookupResult &R,
7273	bool HasTrailingLParen);
7274
7275	/// BuildQualifiedDeclarationNameExpr - Build a C++ qualified
7276	/// declaration name, generally during template instantiation.
7277	/// There's a large number of things which don't need to be done along
7278	/// this path.
7279	ExprResult BuildQualifiedDeclarationNameExpr(
7280	CXXScopeSpec &SS, const DeclarationNameInfo &NameInfo,
7281	bool IsAddressOfOperand, TypeSourceInfo RecoveryTSI = nullptr**);
7282
7283	ExprResult BuildDeclarationNameExpr(const CXXScopeSpec &SS, LookupResult &R,
7284	bool NeedsADL,
7285	bool AcceptInvalidDecl = false);
7286
7287	/// Complete semantic analysis for a reference to the given declaration.
7288	ExprResult BuildDeclarationNameExpr(
7289	const CXXScopeSpec &SS, const DeclarationNameInfo &NameInfo, NamedDecl *D,
7290	NamedDecl FoundD = nullptr*,
7291	const TemplateArgumentListInfo TemplateArgs = nullptr*,
7292	bool AcceptInvalidDecl = false);
7293
7294	// ExpandFunctionLocalPredefinedMacros - Returns a new vector of Tokens,
7295	// where Tokens representing function local predefined macros (such as
7296	// __FUNCTION__) are replaced (expanded) with string-literal Tokens.
7297	std::vector<Token> ExpandFunctionLocalPredefinedMacros(ArrayRef<Token> Toks);
7298
7299	ExprResult BuildPredefinedExpr(SourceLocation Loc, PredefinedIdentKind IK);
7300	ExprResult ActOnPredefinedExpr(SourceLocation Loc, tok::TokenKind Kind);
7301	ExprResult ActOnIntegerConstant(SourceLocation Loc, int64_t Val);
7302
7303	bool CheckLoopHintExpr(Expr E, SourceLocation Loc, bool* AllowZero);
7304
7305	ExprResult ActOnNumericConstant(const Token &Tok, Scope UDLScope = nullptr*);
7306	ExprResult ActOnCharacterConstant(const Token &Tok,
7307	Scope UDLScope = nullptr*);
7308	ExprResult ActOnParenExpr(SourceLocation L, SourceLocation R, Expr *E);
7309	ExprResult ActOnParenListExpr(SourceLocation L, SourceLocation R,
7310	MultiExprArg Val);
7311	ExprResult ActOnCXXParenListInitExpr(ArrayRef<Expr *> Args, QualType T,
7312	unsigned NumUserSpecifiedExprs,
7313	SourceLocation InitLoc,
7314	SourceLocation LParenLoc,
7315	SourceLocation RParenLoc);
7316
7317	/// ActOnStringLiteral - The specified tokens were lexed as pasted string
7318	/// fragments (e.g. "foo" "bar" L"baz"). The result string has to handle
7319	/// string concatenation ([C99 5.1.1.2, translation phase #6]), so it may come
7320	/// from multiple tokens. However, the common case is that StringToks points
7321	/// to one string.
7322	ExprResult ActOnStringLiteral(ArrayRef<Token> StringToks,
7323	Scope UDLScope = nullptr*);
7324
7325	ExprResult ActOnUnevaluatedStringLiteral(ArrayRef<Token> StringToks);
7326
7327	/// ControllingExprOrType is either an opaque pointer coming out of a
7328	/// ParsedType or an Expr . FIXME: it'd be better to split this interface*
7329	/// into two so we don't take a void , but that's awkward because one of*
7330	/// the operands is either a ParsedType or an Expr , which doesn't lend*
7331	/// itself to generic code very well.
7332	ExprResult ActOnGenericSelectionExpr(SourceLocation KeyLoc,
7333	SourceLocation DefaultLoc,
7334	SourceLocation RParenLoc,
7335	bool PredicateIsExpr,
7336	void *ControllingExprOrType,
7337	ArrayRef<ParsedType> ArgTypes,
7338	ArrayRef<Expr *> ArgExprs);
7339	/// ControllingExprOrType is either a TypeSourceInfo or an Expr . FIXME:
7340	/// it'd be better to split this interface into two so we don't take a
7341	/// void , but see the FIXME on ActOnGenericSelectionExpr as to why that*
7342	/// isn't a trivial change.
7343	ExprResult CreateGenericSelectionExpr(SourceLocation KeyLoc,
7344	SourceLocation DefaultLoc,
7345	SourceLocation RParenLoc,
7346	bool PredicateIsExpr,
7347	void *ControllingExprOrType,
7348	ArrayRef<TypeSourceInfo *> Types,
7349	ArrayRef<Expr *> Exprs);
7350
7351	// Binary/Unary Operators. 'Tok' is the token for the operator.
7352	ExprResult CreateBuiltinUnaryOp(SourceLocation OpLoc, UnaryOperatorKind Opc,
7353	Expr InputExpr, bool* IsAfterAmp = false);
7354	ExprResult BuildUnaryOp(Scope *S, SourceLocation OpLoc, UnaryOperatorKind Opc,
7355	Expr Input, bool* IsAfterAmp = false);
7356
7357	/// Unary Operators. 'Tok' is the token for the operator.
7358	ExprResult ActOnUnaryOp(Scope *S, SourceLocation OpLoc, tok::TokenKind Op,
7359	Expr Input, bool* IsAfterAmp = false);
7360
7361	/// Determine whether the given expression is a qualified member
7362	/// access expression, of a form that could be turned into a pointer to member
7363	/// with the address-of operator.
7364	bool isQualifiedMemberAccess(Expr *E);
7365	bool CheckUseOfCXXMethodAsAddressOfOperand(SourceLocation OpLoc,
7366	const Expr *Op,
7367	const CXXMethodDecl *MD);
7368
7369	/// CheckAddressOfOperand - The operand of & must be either a function
7370	/// designator or an lvalue designating an object. If it is an lvalue, the
7371	/// object cannot be declared with storage class register or be a bit field.
7372	/// Note: The usual conversions are not* applied to the operand of the &*
7373	/// operator (C99 6.3.2.1p[2-4]), and its result is never an lvalue.
7374	/// In C++, the operand might be an overloaded function name, in which case
7375	/// we allow the '&' but retain the overloaded-function type.
7376	QualType CheckAddressOfOperand(ExprResult &Operand, SourceLocation OpLoc);
7377
7378	/// ActOnAlignasTypeArgument - Handle @c alignas(type-id) and @c
7379	/// _Alignas(type-name) .
7380	/// [dcl.align] An alignment-specifier of the form
7381	/// alignas(type-id) has the same effect as alignas(alignof(type-id)).
7382	///
7383	/// [N1570 6.7.5] _Alignas(type-name) is equivalent to
7384	/// _Alignas(_Alignof(type-name)).
7385	bool ActOnAlignasTypeArgument(StringRef KWName, ParsedType Ty,
7386	SourceLocation OpLoc, SourceRange R);
7387	bool CheckAlignasTypeArgument(StringRef KWName, TypeSourceInfo *TInfo,
7388	SourceLocation OpLoc, SourceRange R);
7389
7390	/// Build a sizeof or alignof expression given a type operand.
7391	ExprResult CreateUnaryExprOrTypeTraitExpr(TypeSourceInfo *TInfo,
7392	SourceLocation OpLoc,
7393	UnaryExprOrTypeTrait ExprKind,
7394	SourceRange R);
7395
7396	/// Build a sizeof or alignof expression given an expression
7397	/// operand.
7398	ExprResult CreateUnaryExprOrTypeTraitExpr(Expr *E, SourceLocation OpLoc,
7399	UnaryExprOrTypeTrait ExprKind);
7400
7401	/// ActOnUnaryExprOrTypeTraitExpr - Handle @c sizeof(type) and @c sizeof @c
7402	/// expr and the same for @c alignof and @c __alignof
7403	/// Note that the ArgRange is invalid if isType is false.
7404	ExprResult ActOnUnaryExprOrTypeTraitExpr(SourceLocation OpLoc,
7405	UnaryExprOrTypeTrait ExprKind,
7406	bool IsType, void *TyOrEx,
7407	SourceRange ArgRange);
7408
7409	/// Check for operands with placeholder types and complain if found.
7410	/// Returns ExprError() if there was an error and no recovery was possible.
7411	ExprResult CheckPlaceholderExpr(Expr *E);
7412	bool CheckVecStepExpr(Expr *E);
7413
7414	/// Check the constraints on expression operands to unary type expression
7415	/// and type traits.
7416	///
7417	/// Completes any types necessary and validates the constraints on the operand
7418	/// expression. The logic mostly mirrors the type-based overload, but may
7419	/// modify the expression as it completes the type for that expression through
7420	/// template instantiation, etc.
7421	bool CheckUnaryExprOrTypeTraitOperand(Expr *E, UnaryExprOrTypeTrait ExprKind);
7422
7423	/// Check the constraints on operands to unary expression and type
7424	/// traits.
7425	///
7426	/// This will complete any types necessary, and validate the various
7427	/// constraints on those operands.
7428	///
7429	/// The UsualUnaryConversions() function is not* called by this routine.*
7430	/// C99 6.3.2.1p[2-4] all state:
7431	/// Except when it is the operand of the sizeof operator ...
7432	///
7433	/// C++ [expr.sizeof]p4
7434	/// The lvalue-to-rvalue, array-to-pointer, and function-to-pointer
7435	/// standard conversions are not applied to the operand of sizeof.
7436	///
7437	/// This policy is followed for all of the unary trait expressions.
7438	bool CheckUnaryExprOrTypeTraitOperand(QualType ExprType, SourceLocation OpLoc,
7439	SourceRange ExprRange,
7440	UnaryExprOrTypeTrait ExprKind,
7441	StringRef KWName);
7442
7443	ExprResult ActOnPostfixUnaryOp(Scope *S, SourceLocation OpLoc,
7444	tok::TokenKind Kind, Expr *Input);
7445
7446	ExprResult ActOnArraySubscriptExpr(Scope S, Expr Base, SourceLocation LLoc,
7447	MultiExprArg ArgExprs,
7448	SourceLocation RLoc);
7449	ExprResult CreateBuiltinArraySubscriptExpr(Expr *Base, SourceLocation LLoc,
7450	Expr *Idx, SourceLocation RLoc);
7451
7452	ExprResult CreateBuiltinMatrixSingleSubscriptExpr(Expr Base, Expr RowIdx,
7453	SourceLocation RBLoc);
7454
7455	ExprResult CreateBuiltinMatrixSubscriptExpr(Expr Base, Expr RowIdx,
7456	Expr *ColumnIdx,
7457	SourceLocation RBLoc);
7458
7459	/// ConvertArgumentsForCall - Converts the arguments specified in
7460	/// Args/NumArgs to the parameter types of the function FDecl with
7461	/// function prototype Proto. Call is the call expression itself, and
7462	/// Fn is the function expression. For a C++ member function, this
7463	/// routine does not attempt to convert the object argument. Returns
7464	/// true if the call is ill-formed.
7465	bool ConvertArgumentsForCall(CallExpr Call, Expr Fn, FunctionDecl *FDecl,
7466	const FunctionProtoType *Proto,
7467	ArrayRef<Expr *> Args, SourceLocation RParenLoc,
7468	bool ExecConfig = false);
7469
7470	/// CheckStaticArrayArgument - If the given argument corresponds to a static
7471	/// array parameter, check that it is non-null, and that if it is formed by
7472	/// array-to-pointer decay, the underlying array is sufficiently large.
7473	///
7474	/// C99 6.7.5.3p7: If the keyword static also appears within the [ and ] of
7475	/// the array type derivation, then for each call to the function, the value
7476	/// of the corresponding actual argument shall provide access to the first
7477	/// element of an array with at least as many elements as specified by the
7478	/// size expression.
7479	void CheckStaticArrayArgument(SourceLocation CallLoc, ParmVarDecl *Param,
7480	const Expr *ArgExpr);
7481
7482	/// ActOnCallExpr - Handle a call to Fn with the specified array of arguments.
7483	/// This provides the location of the left/right parens and a list of comma
7484	/// locations.
7485	ExprResult ActOnCallExpr(Scope S, Expr Fn, SourceLocation LParenLoc,
7486	MultiExprArg ArgExprs, SourceLocation RParenLoc,
7487	Expr ExecConfig = nullptr*);
7488
7489	/// BuildCallExpr - Handle a call to Fn with the specified array of arguments.
7490	/// This provides the location of the left/right parens and a list of comma
7491	/// locations.
7492	ExprResult BuildCallExpr(Scope S, Expr Fn, SourceLocation LParenLoc,
7493	MultiExprArg ArgExprs, SourceLocation RParenLoc,
7494	Expr ExecConfig = nullptr*,
7495	bool IsExecConfig = false,
7496	bool AllowRecovery = false);
7497
7498	/// BuildBuiltinCallExpr - Create a call to a builtin function specified by Id
7499	// with the specified CallArgs
7500	Expr *BuildBuiltinCallExpr(SourceLocation Loc, Builtin::ID Id,
7501	MultiExprArg CallArgs);
7502
7503	using ADLCallKind = CallExpr::ADLCallKind;
7504
7505	/// BuildResolvedCallExpr - Build a call to a resolved expression,
7506	/// i.e. an expression not of \p OverloadTy. The expression should
7507	/// unary-convert to an expression of function-pointer or
7508	/// block-pointer type.
7509	///
7510	/// \param NDecl the declaration being called, if available
7511	ExprResult
7512	BuildResolvedCallExpr(Expr Fn, NamedDecl NDecl, SourceLocation LParenLoc,
7513	ArrayRef<Expr *> Arg, SourceLocation RParenLoc,
7514	Expr Config = nullptr, bool* IsExecConfig = false,
7515	ADLCallKind UsesADL = ADLCallKind::NotADL);
7516
7517	ExprResult ActOnCastExpr(Scope *S, SourceLocation LParenLoc, Declarator &D,
7518	ParsedType &Ty, SourceLocation RParenLoc,
7519	Expr *CastExpr);
7520
7521	/// Prepares for a scalar cast, performing all the necessary stages
7522	/// except the final cast and returning the kind required.
7523	CastKind PrepareScalarCast(ExprResult &src, QualType destType);
7524
7525	/// Build an altivec or OpenCL literal.
7526	ExprResult BuildVectorLiteral(SourceLocation LParenLoc,
7527	SourceLocation RParenLoc, Expr *E,
7528	TypeSourceInfo *TInfo);
7529
7530	/// This is not an AltiVec-style cast or or C++ direct-initialization, so turn
7531	/// the ParenListExpr into a sequence of comma binary operators.
7532	ExprResult MaybeConvertParenListExprToParenExpr(Scope S, Expr ME);
7533
7534	ExprResult ActOnCompoundLiteral(SourceLocation LParenLoc, ParsedType Ty,
7535	SourceLocation RParenLoc, Expr *InitExpr);
7536
7537	ExprResult BuildCompoundLiteralExpr(SourceLocation LParenLoc,
7538	TypeSourceInfo *TInfo,
7539	SourceLocation RParenLoc,
7540	Expr *LiteralExpr);
7541
7542	ExprResult ActOnInitList(SourceLocation LBraceLoc, MultiExprArg InitArgList,
7543	SourceLocation RBraceLoc);
7544
7545	ExprResult BuildInitList(SourceLocation LBraceLoc, MultiExprArg InitArgList,
7546	SourceLocation RBraceLoc, bool IsExplicit);
7547
7548	/// Binary Operators. 'Tok' is the token for the operator.
7549	ExprResult ActOnBinOp(Scope *S, SourceLocation TokLoc, tok::TokenKind Kind,
7550	Expr LHSExpr, Expr RHSExpr);
7551	ExprResult BuildBinOp(Scope *S, SourceLocation OpLoc, BinaryOperatorKind Opc,
7552	Expr LHSExpr, Expr RHSExpr,
7553	bool ForFoldExpression = false);
7554
7555	/// CreateBuiltinBinOp - Creates a new built-in binary operation with
7556	/// operator @p Opc at location @c TokLoc. This routine only supports
7557	/// built-in operations; ActOnBinOp handles overloaded operators.
7558	ExprResult CreateBuiltinBinOp(SourceLocation OpLoc, BinaryOperatorKind Opc,
7559	Expr LHSExpr, Expr RHSExpr,
7560	bool ForFoldExpression = false);
7561	void LookupBinOp(Scope *S, SourceLocation OpLoc, BinaryOperatorKind Opc,
7562	UnresolvedSetImpl &Functions);
7563
7564	/// Look for instances where it is likely the comma operator is confused with
7565	/// another operator. There is an explicit list of acceptable expressions for
7566	/// the left hand side of the comma operator, otherwise emit a warning.
7567	void DiagnoseCommaOperator(const Expr *LHS, SourceLocation Loc);
7568
7569	/// ActOnConditionalOp - Parse a ?: operation. Note that 'LHS' may be null
7570	/// in the case of a the GNU conditional expr extension.
7571	ExprResult ActOnConditionalOp(SourceLocation QuestionLoc,
7572	SourceLocation ColonLoc, Expr *CondExpr,
7573	Expr LHSExpr, Expr RHSExpr);
7574
7575	/// ActOnAddrLabel - Parse the GNU address of label extension: "&&foo".
7576	ExprResult ActOnAddrLabel(SourceLocation OpLoc, SourceLocation LabLoc,
7577	LabelDecl *TheDecl);
7578
7579	void ActOnStartStmtExpr();
7580	ExprResult ActOnStmtExpr(Scope S, SourceLocation LPLoc, Stmt SubStmt,
7581	SourceLocation RPLoc);
7582	ExprResult BuildStmtExpr(SourceLocation LPLoc, Stmt *SubStmt,
7583	SourceLocation RPLoc, unsigned TemplateDepth);
7584	// Handle the final expression in a statement expression.
7585	ExprResult ActOnStmtExprResult(ExprResult E);
7586	void ActOnStmtExprError();
7587
7588	/// __builtin_offsetof(type, a.b[123][456].c)
7589	ExprResult BuildBuiltinOffsetOf(SourceLocation BuiltinLoc,
7590	TypeSourceInfo *TInfo,
7591	const Designation &Desig,
7592	SourceLocation RParenLoc);
7593	ExprResult ActOnBuiltinOffsetOf(Scope *S, SourceLocation BuiltinLoc,
7594	SourceLocation TypeLoc,
7595	ParsedType ParsedArgTy,
7596	const Designation &Desig,
7597	SourceLocation RParenLoc);
7598
7599	// __builtin_choose_expr(constExpr, expr1, expr2)
7600	ExprResult ActOnChooseExpr(SourceLocation BuiltinLoc, Expr *CondExpr,
7601	Expr LHSExpr, Expr RHSExpr,
7602	SourceLocation RPLoc);
7603
7604	// __builtin_va_arg(expr, type)
7605	ExprResult ActOnVAArg(SourceLocation BuiltinLoc, Expr *E, ParsedType Ty,
7606	SourceLocation RPLoc);
7607	ExprResult BuildVAArgExpr(SourceLocation BuiltinLoc, Expr *E,
7608	TypeSourceInfo *TInfo, SourceLocation RPLoc);
7609
7610	// __builtin_LINE(), __builtin_FUNCTION(), __builtin_FUNCSIG(),
7611	// __builtin_FILE(), __builtin_COLUMN(), __builtin_source_location()
7612	ExprResult ActOnSourceLocExpr(SourceLocIdentKind Kind,
7613	SourceLocation BuiltinLoc,
7614	SourceLocation RPLoc);
7615
7616	// #embed
7617	ExprResult ActOnEmbedExpr(SourceLocation EmbedKeywordLoc,
7618	StringLiteral *BinaryData, StringRef FileName);
7619
7620	// Build a potentially resolved SourceLocExpr.
7621	ExprResult BuildSourceLocExpr(SourceLocIdentKind Kind, QualType ResultTy,
7622	SourceLocation BuiltinLoc, SourceLocation RPLoc,
7623	DeclContext *ParentContext);
7624
7625	// __null
7626	ExprResult ActOnGNUNullExpr(SourceLocation TokenLoc);
7627
7628	bool CheckCaseExpression(Expr *E);
7629
7630	//===------------------------- "Block" Extension ------------------------===//
7631
7632	/// ActOnBlockStart - This callback is invoked when a block literal is
7633	/// started.
7634	void ActOnBlockStart(SourceLocation CaretLoc, Scope *CurScope);
7635
7636	/// ActOnBlockArguments - This callback allows processing of block arguments.
7637	/// If there are no arguments, this is still invoked.
7638	void ActOnBlockArguments(SourceLocation CaretLoc, Declarator &ParamInfo,
7639	Scope *CurScope);
7640
7641	/// ActOnBlockError - If there is an error parsing a block, this callback
7642	/// is invoked to pop the information about the block from the action impl.
7643	void ActOnBlockError(SourceLocation CaretLoc, Scope *CurScope);
7644
7645	/// ActOnBlockStmtExpr - This is called when the body of a block statement
7646	/// literal was successfully completed. ^(int x){...}
7647	ExprResult ActOnBlockStmtExpr(SourceLocation CaretLoc, Stmt *Body,
7648	Scope *CurScope);
7649
7650	//===---------------------------- Clang Extensions ----------------------===//
7651
7652	/// ActOnConvertVectorExpr - create a new convert-vector expression from the
7653	/// provided arguments.
7654	///
7655	/// __builtin_convertvector( value, dst type )
7656	///
7657	ExprResult ActOnConvertVectorExpr(Expr *E, ParsedType ParsedDestTy,
7658	SourceLocation BuiltinLoc,
7659	SourceLocation RParenLoc);
7660
7661	//===---------------------------- OpenCL Features -----------------------===//
7662
7663	/// Parse a __builtin_astype expression.
7664	///
7665	/// __builtin_astype( value, dst type )
7666	///
7667	ExprResult ActOnAsTypeExpr(Expr *E, ParsedType ParsedDestTy,
7668	SourceLocation BuiltinLoc,
7669	SourceLocation RParenLoc);
7670
7671	/// Create a new AsTypeExpr node (bitcast) from the arguments.
7672	ExprResult BuildAsTypeExpr(Expr *E, QualType DestTy,
7673	SourceLocation BuiltinLoc,
7674	SourceLocation RParenLoc);
7675
7676	/// Attempts to produce a RecoveryExpr after some AST node cannot be created.
7677	ExprResult CreateRecoveryExpr(SourceLocation Begin, SourceLocation End,
7678	ArrayRef<Expr *> SubExprs,
7679	QualType T = QualType ());
7680
7681	/// Cast a base object to a member's actual type.
7682	///
7683	/// There are two relevant checks:
7684	///
7685	/// C++ [class.access.base]p7:
7686	///
7687	/// If a class member access operator [...] is used to access a non-static
7688	/// data member or non-static member function, the reference is ill-formed
7689	/// if the left operand [...] cannot be implicitly converted to a pointer to
7690	/// the naming class of the right operand.
7691	///
7692	/// C++ [expr.ref]p7:
7693	///
7694	/// If E2 is a non-static data member or a non-static member function, the
7695	/// program is ill-formed if the class of which E2 is directly a member is
7696	/// an ambiguous base (11.8) of the naming class (11.9.3) of E2.
7697	///
7698	/// Note that the latter check does not consider access; the access of the
7699	/// "real" base class is checked as appropriate when checking the access of
7700	/// the member name.
7701	ExprResult PerformObjectMemberConversion(Expr *From,
7702	NestedNameSpecifier Qualifier,
7703	NamedDecl *FoundDecl,
7704	NamedDecl *Member);
7705
7706	/// CheckCallReturnType - Checks that a call expression's return type is
7707	/// complete. Returns true on failure. The location passed in is the location
7708	/// that best represents the call.
7709	bool CheckCallReturnType(QualType ReturnType, SourceLocation Loc,
7710	CallExpr CE, FunctionDecl FD);
7711
7712	/// Emit a warning for all pending noderef expressions that we recorded.
7713	void WarnOnPendingNoDerefs(ExpressionEvaluationContextRecord &Rec);
7714
7715	ExprResult BuildCXXDefaultInitExpr(SourceLocation Loc, FieldDecl *Field);
7716
7717	/// Instantiate or parse a C++ default argument expression as necessary.
7718	/// Return true on error.
7719	bool CheckCXXDefaultArgExpr(SourceLocation CallLoc, FunctionDecl *FD,
7720	ParmVarDecl Param, Expr Init = nullptr,
7721	bool SkipImmediateInvocations = true);
7722
7723	/// BuildCXXDefaultArgExpr - Creates a CXXDefaultArgExpr, instantiating
7724	/// the default expr if needed.
7725	ExprResult BuildCXXDefaultArgExpr(SourceLocation CallLoc, FunctionDecl *FD,
7726	ParmVarDecl Param, Expr Init = nullptr);
7727
7728	/// Wrap the expression in a ConstantExpr if it is a potential immediate
7729	/// invocation.
7730	ExprResult CheckForImmediateInvocation(ExprResult E, FunctionDecl *Decl);
7731
7732	void MarkExpressionAsImmediateEscalating(Expr *E);
7733
7734	// Check that the SME attributes for PSTATE.ZA and PSTATE.SM are compatible.
7735	bool IsInvalidSMECallConversion(QualType FromType, QualType ToType);
7736
7737	/// Abstract base class used for diagnosing integer constant
7738	/// expression violations.
7739	class VerifyICEDiagnoser {
7740	public:
7741	bool Suppress;
7742
7743	VerifyICEDiagnoser(bool Suppress = false) : Suppress(Suppress) {}
7744
7745	virtual SemaDiagnosticBuilder
7746	diagnoseNotICEType(Sema &S, SourceLocation Loc, QualType T);
7747	virtual SemaDiagnosticBuilder diagnoseNotICE(Sema &S,
7748	SourceLocation Loc) = `0`;
7749	virtual SemaDiagnosticBuilder diagnoseFold(Sema &S, SourceLocation Loc);
7750	virtual ~VerifyICEDiagnoser() {}
7751	};
7752
7753	/// VerifyIntegerConstantExpression - Verifies that an expression is an ICE,
7754	/// and reports the appropriate diagnostics. Returns false on success.
7755	/// Can optionally return the value of the expression.
7756	ExprResult
7757	VerifyIntegerConstantExpression(Expr E, llvm::APSInt Result,
7758	VerifyICEDiagnoser &Diagnoser,
7759	AllowFoldKind CanFold = AllowFoldKind::No);
7760	ExprResult
7761	VerifyIntegerConstantExpression(Expr E, llvm::APSInt Result,
7762	unsigned DiagID,
7763	AllowFoldKind CanFold = AllowFoldKind::No);
7764	ExprResult
7765	VerifyIntegerConstantExpression(Expr E, llvm::APSInt Result = nullptr,
7766	AllowFoldKind CanFold = AllowFoldKind::No);
7767	ExprResult
7768	VerifyIntegerConstantExpression(Expr *E,
7769	AllowFoldKind CanFold = AllowFoldKind::No) {
7770	return VerifyIntegerConstantExpression(E, Result: nullptr, CanFold);
7771	}
7772
7773	/// DiagnoseAssignmentAsCondition - Given that an expression is
7774	/// being used as a boolean condition, warn if it's an assignment.
7775	void DiagnoseAssignmentAsCondition(Expr *E);
7776
7777	/// Redundant parentheses over an equality comparison can indicate
7778	/// that the user intended an assignment used as condition.
7779	void DiagnoseEqualityWithExtraParens(ParenExpr *ParenE);
7780
7781	class FullExprArg {
7782	public:
7783	FullExprArg() : E(nullptr) {}
7784	FullExprArg(Sema &actions) : E(nullptr) {}
7785
7786	ExprResult release() { return E; }
7787
7788	Expr get() const* { return E; }
7789
7790	Expr *operator->() { return E; }
7791
7792	private:
7793	// FIXME: No need to make the entire Sema class a friend when it's just
7794	// Sema::MakeFullExpr that needs access to the constructor below.
7795	friend class Sema;
7796
7797	explicit FullExprArg(Expr *expr) : E(expr) {}
7798
7799	Expr *E;
7800	};
7801
7802	FullExprArg MakeFullExpr(Expr *Arg) {
7803	return MakeFullExpr(Arg, CC: Arg ? Arg->getExprLoc() : SourceLocation ());
7804	}
7805	FullExprArg MakeFullExpr(Expr *Arg, SourceLocation CC) {
7806	return FullExprArg (
7807	ActOnFinishFullExpr(Expr: Arg, CC, /DiscardedValue/ DiscardedValue: false).get());
7808	}
7809	FullExprArg MakeFullDiscardedValueExpr(Expr *Arg) {
7810	ExprResult FE =
7811	ActOnFinishFullExpr(Expr: Arg, CC: Arg ? Arg->getExprLoc() : SourceLocation (),
7812	/DiscardedValue/ DiscardedValue: true);
7813	return FullExprArg (FE.get());
7814	}
7815
7816	class ConditionResult {
7817	Decl *ConditionVar;
7818	ExprResult Condition;
7819	bool Invalid;
7820	std::optional<bool> KnownValue;
7821
7822	friend class Sema;
7823	ConditionResult(Sema &S, Decl *ConditionVar, ExprResult Condition,
7824	bool IsConstexpr)
7825	: ConditionVar(ConditionVar), Condition (Condition), Invalid(false) {
7826	if (IsConstexpr && Condition.get()) {
7827	if (std::optional<llvm::APSInt> Val =
7828	Condition.get()->getIntegerConstantExpr(Ctx: S.Context)) {
7829	KnownValue = !!(*Val);
7830	}
7831	}
7832	}
7833	explicit ConditionResult(bool Invalid)
7834	: ConditionVar(nullptr), Condition (Invalid), Invalid(Invalid),
7835	KnownValue (std::nullopt) {}
7836
7837	public:
7838	ConditionResult() : ConditionResult (false) {}
7839	bool isInvalid() const { return Invalid; }
7840	std::pair<VarDecl , Expr > get() const {
7841	return std::make_pair(x: cast_or_null<VarDecl>(Val: ConditionVar),
7842	y: Condition.get());
7843	}
7844	std::optional<bool> getKnownValue() const { return KnownValue; }
7845	};
7846	static ConditionResult ConditionError() { return ConditionResult (true); }
7847
7848	/// CheckBooleanCondition - Diagnose problems involving the use of
7849	/// the given expression as a boolean condition (e.g. in an if
7850	/// statement). Also performs the standard function and array
7851	/// decays, possibly changing the input variable.
7852	///
7853	/// \param Loc - A location associated with the condition, e.g. the
7854	/// 'if' keyword.
7855	/// \return true iff there were any errors
7856	ExprResult CheckBooleanCondition(SourceLocation Loc, Expr *E,
7857	bool IsConstexpr = false);
7858
7859	enum class ConditionKind {
7860	Boolean, ///< A boolean condition, from 'if', 'while', 'for', or 'do'.
7861	ConstexprIf, ///< A constant boolean condition from 'if constexpr'.
7862	Switch ///< An integral condition for a 'switch' statement.
7863	};
7864
7865	ConditionResult ActOnCondition(Scope S, SourceLocation Loc, Expr SubExpr,
7866	ConditionKind CK, bool MissingOK = false);
7867
7868	QualType CheckConditionalOperands( // C99 6.5.15
7869	ExprResult &Cond, ExprResult &LHS, ExprResult &RHS, ExprValueKind &VK,
7870	ExprObjectKind &OK, SourceLocation QuestionLoc);
7871
7872	/// Emit a specialized diagnostic when one expression is a null pointer
7873	/// constant and the other is not a pointer. Returns true if a diagnostic is
7874	/// emitted.
7875	bool DiagnoseConditionalForNull(const Expr LHSExpr, const* Expr *RHSExpr,
7876	SourceLocation QuestionLoc);
7877
7878	/// type checking for vector binary operators.
7879	QualType CheckVectorOperands(ExprResult &LHS, ExprResult &RHS,
7880	SourceLocation Loc, bool IsCompAssign,
7881	bool AllowBothBool, bool AllowBoolConversion,
7882	bool AllowBoolOperation, bool ReportInvalid);
7883
7884	/// Return a signed ext_vector_type that is of identical size and number of
7885	/// elements. For floating point vectors, return an integer type of identical
7886	/// size and number of elements. In the non ext_vector_type case, search from
7887	/// the largest type to the smallest type to avoid cases where long long ==
7888	/// long, where long gets picked over long long.
7889	QualType GetSignedVectorType(QualType V);
7890	QualType GetSignedSizelessVectorType(QualType V);
7891
7892	/// CheckVectorCompareOperands - vector comparisons are a clang extension that
7893	/// operates on extended vector types. Instead of producing an IntTy result,
7894	/// like a scalar comparison, a vector comparison produces a vector of integer
7895	/// types.
7896	QualType CheckVectorCompareOperands(ExprResult &LHS, ExprResult &RHS,
7897	SourceLocation Loc,
7898	BinaryOperatorKind Opc);
7899	QualType CheckSizelessVectorCompareOperands(ExprResult &LHS, ExprResult &RHS,
7900	SourceLocation Loc,
7901	BinaryOperatorKind Opc);
7902	QualType CheckMatrixCompareOperands(ExprResult &LHS, ExprResult &RHS,
7903	SourceLocation Loc,
7904	BinaryOperatorKind Opc);
7905	QualType CheckVectorLogicalOperands(ExprResult &LHS, ExprResult &RHS,
7906	SourceLocation Loc,
7907	BinaryOperatorKind Opc);
7908	QualType CheckMatrixLogicalOperands(ExprResult &LHS, ExprResult &RHS,
7909	SourceLocation Loc,
7910	BinaryOperatorKind Opc);
7911	// type checking for sizeless vector binary operators.
7912	QualType CheckSizelessVectorOperands(ExprResult &LHS, ExprResult &RHS,
7913	SourceLocation Loc, bool IsCompAssign,
7914	ArithConvKind OperationKind);
7915
7916	/// Type checking for matrix binary operators.
7917	QualType CheckMatrixElementwiseOperands(ExprResult &LHS, ExprResult &RHS,
7918	SourceLocation Loc,
7919	bool IsCompAssign);
7920	QualType CheckMatrixMultiplyOperands(ExprResult &LHS, ExprResult &RHS,
7921	SourceLocation Loc, bool IsCompAssign);
7922
7923	/// Are the two types SVE-bitcast-compatible types? I.e. is bitcasting from
7924	/// the first SVE type (e.g. an SVE VLAT) to the second type (e.g. an SVE
7925	/// VLST) allowed?
7926	///
7927	/// This will also return false if the two given types do not make sense from
7928	/// the perspective of SVE bitcasts.
7929	bool isValidSveBitcast(QualType srcType, QualType destType);
7930
7931	/// Are the two types matrix types and do they have the same dimensions i.e.
7932	/// do they have the same number of rows and the same number of columns?
7933	bool areMatrixTypesOfTheSameDimension(QualType srcTy, QualType destTy);
7934
7935	bool areVectorTypesSameSize(QualType srcType, QualType destType);
7936
7937	/// Are the two types lax-compatible vector types? That is, given
7938	/// that one of them is a vector, do they have equal storage sizes,
7939	/// where the storage size is the number of elements times the element
7940	/// size?
7941	///
7942	/// This will also return false if either of the types is neither a
7943	/// vector nor a real type.
7944	bool areLaxCompatibleVectorTypes(QualType srcType, QualType destType);
7945
7946	/// Is this a legal conversion between two types, one of which is
7947	/// known to be a vector type?
7948	bool isLaxVectorConversion(QualType srcType, QualType destType);
7949
7950	// This returns true if at least one of the types is an altivec vector.
7951	bool anyAltivecTypes(QualType srcType, QualType destType);
7952
7953	// type checking C++ declaration initializers (C++ [dcl.init]).
7954
7955	/// Check a cast of an unknown-any type. We intentionally only
7956	/// trigger this for C-style casts.
7957	ExprResult checkUnknownAnyCast(SourceRange TypeRange, QualType CastType,
7958	Expr *CastExpr, CastKind &CastKind,
7959	ExprValueKind &VK, CXXCastPath &Path);
7960
7961	/// Force an expression with unknown-type to an expression of the
7962	/// given type.
7963	ExprResult forceUnknownAnyToType(Expr *E, QualType ToType);
7964
7965	/// Type-check an expression that's being passed to an
7966	/// __unknown_anytype parameter.
7967	ExprResult checkUnknownAnyArg(SourceLocation callLoc, Expr *result,
7968	QualType &paramType);
7969
7970	// CheckMatrixCast - Check type constraints for matrix casts.
7971	// We allow casting between matrixes of the same dimensions i.e. when they
7972	// have the same number of rows and column. Returns true if the cast is
7973	// invalid.
7974	bool CheckMatrixCast(SourceRange R, QualType DestTy, QualType SrcTy,
7975	CastKind &Kind);
7976
7977	// CheckVectorCast - check type constraints for vectors.
7978	// Since vectors are an extension, there are no C standard reference for this.
7979	// We allow casting between vectors and integer datatypes of the same size.
7980	// returns true if the cast is invalid
7981	bool CheckVectorCast(SourceRange R, QualType VectorTy, QualType Ty,
7982	CastKind &Kind);
7983
7984	/// Prepare `SplattedExpr` for a vector splat operation, adding
7985	/// implicit casts if necessary.
7986	ExprResult prepareVectorSplat(QualType VectorTy, Expr *SplattedExpr);
7987
7988	/// Prepare `SplattedExpr` for a matrix splat operation, adding
7989	/// implicit casts if necessary.
7990	ExprResult prepareMatrixSplat(QualType MatrixTy, Expr *SplattedExpr);
7991
7992	// CheckExtVectorCast - check type constraints for extended vectors.
7993	// Since vectors are an extension, there are no C standard reference for this.
7994	// We allow casting between vectors and integer datatypes of the same size,
7995	// or vectors and the element type of that vector.
7996	// returns the cast expr
7997	ExprResult CheckExtVectorCast(SourceRange R, QualType DestTy, Expr *CastExpr,
7998	CastKind &Kind);
7999
8000	QualType PreferredConditionType(ConditionKind K) const {
8001	return K == ConditionKind::Switch ? Context.IntTy : Context.BoolTy;
8002	}
8003
8004	// UsualUnaryConversions - promotes integers (C99 6.3.1.1p2), converts
8005	// functions and arrays to their respective pointers (C99 6.3.2.1), and
8006	// promotes floating-piont types according to the language semantics.
8007	ExprResult UsualUnaryConversions(Expr *E);
8008
8009	// UsualUnaryFPConversions - promotes floating-point types according to the
8010	// current language semantics.
8011	ExprResult UsualUnaryFPConversions(Expr *E);
8012
8013	/// CallExprUnaryConversions - a special case of an unary conversion
8014	/// performed on a function designator of a call expression.
8015	ExprResult CallExprUnaryConversions(Expr *E);
8016
8017	// DefaultFunctionArrayConversion - converts functions and arrays
8018	// to their respective pointers (C99 6.3.2.1).
8019	ExprResult DefaultFunctionArrayConversion(Expr E, bool* Diagnose = true);
8020
8021	// DefaultFunctionArrayLvalueConversion - converts functions and
8022	// arrays to their respective pointers and performs the
8023	// lvalue-to-rvalue conversion.
8024	ExprResult DefaultFunctionArrayLvalueConversion(Expr *E,
8025	bool Diagnose = true);
8026
8027	// DefaultLvalueConversion - performs lvalue-to-rvalue conversion on
8028	// the operand. This function is a no-op if the operand has a function type
8029	// or an array type.
8030	ExprResult DefaultLvalueConversion(Expr *E);
8031
8032	// DefaultArgumentPromotion (C99 6.5.2.2p6). Used for function calls that
8033	// do not have a prototype. Integer promotions are performed on each
8034	// argument, and arguments that have type float are promoted to double.
8035	ExprResult DefaultArgumentPromotion(Expr *E);
8036
8037	VariadicCallType getVariadicCallType(FunctionDecl *FDecl,
8038	const FunctionProtoType *Proto,
8039	Expr *Fn);
8040
8041	/// Determine the degree of POD-ness for an expression.
8042	/// Incomplete types are considered POD, since this check can be performed
8043	/// when we're in an unevaluated context.
8044	VarArgKind isValidVarArgType(const QualType &Ty);
8045
8046	/// Check to see if the given expression is a valid argument to a variadic
8047	/// function, issuing a diagnostic if not.
8048	void checkVariadicArgument(const Expr *E, VariadicCallType CT);
8049
8050	/// GatherArgumentsForCall - Collector argument expressions for various
8051	/// form of call prototypes.
8052	bool GatherArgumentsForCall(
8053	SourceLocation CallLoc, FunctionDecl *FDecl,
8054	const FunctionProtoType Proto, unsigned* FirstParam,
8055	ArrayRef<Expr > Args, SmallVectorImpl<Expr > &AllArgs,
8056	VariadicCallType CallType = VariadicCallType::DoesNotApply,
8057	bool AllowExplicit = false, bool IsListInitialization = false);
8058
8059	// DefaultVariadicArgumentPromotion - Like DefaultArgumentPromotion, but
8060	// will create a runtime trap if the resulting type is not a POD type.
8061	ExprResult DefaultVariadicArgumentPromotion(Expr *E, VariadicCallType CT,
8062	FunctionDecl *FDecl);
8063
8064	// Check that the usual arithmetic conversions can be performed on this pair
8065	// of expressions that might be of enumeration type.
8066	void checkEnumArithmeticConversions(Expr LHS, Expr RHS, SourceLocation Loc,
8067	ArithConvKind ACK);
8068
8069	// UsualArithmeticConversions - performs the UsualUnaryConversions on it's
8070	// operands and then handles various conversions that are common to binary
8071	// operators (C99 6.3.1.8). If both operands aren't arithmetic, this
8072	// routine returns the first non-arithmetic type found. The client is
8073	// responsible for emitting appropriate error diagnostics.
8074	QualType UsualArithmeticConversions(ExprResult &LHS, ExprResult &RHS,
8075	SourceLocation Loc, ArithConvKind ACK);
8076
8077	bool IsAssignConvertCompatible(AssignConvertType ConvTy) {
8078	switch (ConvTy) {
8079	default:
8080	return false;
8081	case AssignConvertType::Compatible:
8082	case AssignConvertType::CompatiblePointerDiscardsQualifiers:
8083	case AssignConvertType::CompatibleVoidPtrToNonVoidPtr:
8084	return true;
8085	}
8086	llvm_unreachable("impossible");
8087	}
8088
8089	/// DiagnoseAssignmentResult - Emit a diagnostic, if required, for the
8090	/// assignment conversion type specified by ConvTy. This returns true if the
8091	/// conversion was invalid or false if the conversion was accepted.
8092	bool DiagnoseAssignmentResult(AssignConvertType ConvTy, SourceLocation Loc,
8093	QualType DstType, QualType SrcType,
8094	Expr *SrcExpr, AssignmentAction Action,
8095	bool Complained = nullptr*);
8096
8097	/// CheckAssignmentConstraints - Perform type checking for assignment,
8098	/// argument passing, variable initialization, and function return values.
8099	/// C99 6.5.16.
8100	AssignConvertType CheckAssignmentConstraints(SourceLocation Loc,
8101	QualType LHSType,
8102	QualType RHSType);
8103
8104	/// Check assignment constraints and optionally prepare for a conversion of
8105	/// the RHS to the LHS type. The conversion is prepared for if ConvertRHS
8106	/// is true.
8107	AssignConvertType CheckAssignmentConstraints(QualType LHSType,
8108	ExprResult &RHS, CastKind &Kind,
8109	bool ConvertRHS = true);
8110
8111	/// Check assignment constraints for an assignment of RHS to LHSType.
8112	///
8113	/// \param LHSType The destination type for the assignment.
8114	/// \param RHS The source expression for the assignment.
8115	/// \param Diagnose If \c true, diagnostics may be produced when checking
8116	/// for assignability. If a diagnostic is produced, \p RHS will be
8117	/// set to ExprError(). Note that this function may still return
8118	/// without producing a diagnostic, even for an invalid assignment.
8119	/// \param DiagnoseCFAudited If \c true, the target is a function parameter
8120	/// in an audited Core Foundation API and does not need to be checked
8121	/// for ARC retain issues.
8122	/// \param ConvertRHS If \c true, \p RHS will be updated to model the
8123	/// conversions necessary to perform the assignment. If \c false,
8124	/// \p Diagnose must also be \c false.
8125	AssignConvertType CheckSingleAssignmentConstraints(
8126	QualType LHSType, ExprResult &RHS, bool Diagnose = true,
8127	bool DiagnoseCFAudited = false, bool ConvertRHS = true);
8128
8129	// If the lhs type is a transparent union, check whether we
8130	// can initialize the transparent union with the given expression.
8131	AssignConvertType CheckTransparentUnionArgumentConstraints(QualType ArgType,
8132	ExprResult &RHS);
8133
8134	/// the following "Check" methods will return a valid/converted QualType
8135	/// or a null QualType (indicating an error diagnostic was issued).
8136
8137	/// type checking binary operators (subroutines of CreateBuiltinBinOp).
8138	QualType InvalidOperands(SourceLocation Loc, ExprResult &LHS,
8139	ExprResult &RHS);
8140
8141	/// Diagnose cases where a scalar was implicitly converted to a vector and
8142	/// diagnose the underlying types. Otherwise, diagnose the error
8143	/// as invalid vector logical operands for non-C++ cases.
8144	QualType InvalidLogicalVectorOperands(SourceLocation Loc, ExprResult &LHS,
8145	ExprResult &RHS);
8146
8147	QualType CheckMultiplyDivideOperands( // C99 6.5.5
8148	ExprResult &LHS, ExprResult &RHS, SourceLocation Loc,
8149	BinaryOperatorKind Opc);
8150	QualType CheckRemainderOperands( // C99 6.5.5
8151	ExprResult &LHS, ExprResult &RHS, SourceLocation Loc,
8152	bool IsCompAssign = false);
8153	QualType CheckAdditionOperands( // C99 6.5.6
8154	ExprResult &LHS, ExprResult &RHS, SourceLocation Loc,
8155	BinaryOperatorKind Opc, QualType CompLHSTy = nullptr*);
8156	QualType CheckSubtractionOperands( // C99 6.5.6
8157	ExprResult &LHS, ExprResult &RHS, SourceLocation Loc,
8158	BinaryOperatorKind Opc, QualType CompLHSTy = nullptr*);
8159	QualType CheckShiftOperands( // C99 6.5.7
8160	ExprResult &LHS, ExprResult &RHS, SourceLocation Loc,
8161	BinaryOperatorKind Opc, bool IsCompAssign = false);
8162	void CheckPtrComparisonWithNullChar(ExprResult &E, ExprResult &NullE);
8163	QualType CheckCompareOperands( // C99 6.5.8/9
8164	ExprResult &LHS, ExprResult &RHS, SourceLocation Loc,
8165	BinaryOperatorKind Opc);
8166	QualType CheckBitwiseOperands( // C99 6.5.[10...12]
8167	ExprResult &LHS, ExprResult &RHS, SourceLocation Loc,
8168	BinaryOperatorKind Opc);
8169	QualType CheckLogicalOperands( // C99 6.5.[13,14]
8170	ExprResult &LHS, ExprResult &RHS, SourceLocation Loc,
8171	BinaryOperatorKind Opc);
8172	// CheckAssignmentOperands is used for both simple and compound assignment.
8173	// For simple assignment, pass both expressions and a null converted type.
8174	// For compound assignment, pass both expressions and the converted type.
8175	QualType CheckAssignmentOperands( // C99 6.5.16.[1,2]
8176	Expr *LHSExpr, ExprResult &RHS, SourceLocation Loc, QualType CompoundType,
8177	BinaryOperatorKind Opc);
8178
8179	/// To be used for checking whether the arguments being passed to
8180	/// function exceeds the number of parameters expected for it.
8181	static bool TooManyArguments(size_t NumParams, size_t NumArgs,
8182	bool PartialOverloading = false) {
8183	// We check whether we're just after a comma in code-completion.
8184	if (NumArgs > `0` && PartialOverloading)
8185	return NumArgs + `1` > NumParams; // If so, we view as an extra argument.
8186	return NumArgs > NumParams;
8187	}
8188
8189	/// Whether the AST is currently being rebuilt to correct immediate
8190	/// invocations. Immediate invocation candidates and references to consteval
8191	/// functions aren't tracked when this is set.
8192	bool RebuildingImmediateInvocation = false;
8193
8194	bool isAlwaysConstantEvaluatedContext() const {
8195	const ExpressionEvaluationContextRecord &Ctx = currentEvaluationContext();
8196	return (Ctx.isConstantEvaluated() \|\| isConstantEvaluatedOverride) &&
8197	!Ctx.InConditionallyConstantEvaluateContext;
8198	}
8199
8200	/// Determines whether we are currently in a context that
8201	/// is not evaluated as per C++ [expr] p5.
8202	bool isUnevaluatedContext() const {
8203	return currentEvaluationContext().isUnevaluated();
8204	}
8205
8206	bool isImmediateFunctionContext() const {
8207	return currentEvaluationContext().isImmediateFunctionContext();
8208	}
8209
8210	bool isInLifetimeExtendingContext() const {
8211	return currentEvaluationContext().InLifetimeExtendingContext;
8212	}
8213
8214	bool needsRebuildOfDefaultArgOrInit() const {
8215	return currentEvaluationContext().RebuildDefaultArgOrDefaultInit;
8216	}
8217
8218	bool isCheckingDefaultArgumentOrInitializer() const {
8219	const ExpressionEvaluationContextRecord &Ctx = currentEvaluationContext();
8220	return (Ctx.Context ==
8221	ExpressionEvaluationContext::PotentiallyEvaluatedIfUsed) \|\|
8222	Ctx.IsCurrentlyCheckingDefaultArgumentOrInitializer;
8223	}
8224
8225	std::optional<ExpressionEvaluationContextRecord::InitializationContext>
8226	InnermostDeclarationWithDelayedImmediateInvocations() const {
8227	assert(!ExprEvalContexts.empty() &&
8228	"Must be in an expression evaluation context");
8229	for (const auto &Ctx : llvm::reverse(C: ExprEvalContexts)) {
8230	if (Ctx.Context == ExpressionEvaluationContext::PotentiallyEvaluated &&
8231	Ctx.DelayedDefaultInitializationContext)
8232	return Ctx.DelayedDefaultInitializationContext;
8233	if (Ctx.isConstantEvaluated() \|\| Ctx.isImmediateFunctionContext() \|\|
8234	Ctx.isUnevaluated())
8235	break;
8236	}
8237	return std::nullopt;
8238	}
8239
8240	std::optional<ExpressionEvaluationContextRecord::InitializationContext>
8241	OutermostDeclarationWithDelayedImmediateInvocations() const {
8242	assert(!ExprEvalContexts.empty() &&
8243	"Must be in an expression evaluation context");
8244	std::optional<ExpressionEvaluationContextRecord::InitializationContext> Res;
8245	for (auto &Ctx : llvm::reverse(C: ExprEvalContexts)) {
8246	if (Ctx.Context == ExpressionEvaluationContext::PotentiallyEvaluated &&
8247	!Ctx.DelayedDefaultInitializationContext && Res)
8248	break;
8249	if (Ctx.isConstantEvaluated() \|\| Ctx.isImmediateFunctionContext() \|\|
8250	Ctx.isUnevaluated())
8251	break;
8252	Res = Ctx.DelayedDefaultInitializationContext;
8253	}
8254	return Res;
8255	}
8256
8257	/// Returns a field in a CXXRecordDecl that has the same name as the decl \p
8258	/// SelfAssigned when inside a CXXMethodDecl.
8259	const FieldDecl *
8260	getSelfAssignmentClassMemberCandidate(const ValueDecl *SelfAssigned);
8261
8262	void MaybeSuggestAddingStaticToDecl(const FunctionDecl *D);
8263
8264	template <typename... Ts>
8265	bool RequireCompleteSizedType(SourceLocation Loc, QualType T, unsigned DiagID,
8266	const Ts &...Args) {
8267	SizelessTypeDiagnoser<Ts...> Diagnoser(DiagID, Args...);
8268	return RequireCompleteType(Loc, T, CompleteTypeKind::Normal, Diagnoser);
8269	}
8270
8271	template <typename... Ts>
8272	bool RequireCompleteSizedExprType(Expr E, unsigned* DiagID,
8273	const Ts &...Args) {
8274	SizelessTypeDiagnoser<Ts...> Diagnoser(DiagID, Args...);
8275	return RequireCompleteExprType(E, CompleteTypeKind::Normal, Diagnoser);
8276	}
8277
8278	/// Abstract class used to diagnose incomplete types.
8279	struct TypeDiagnoser {
8280	TypeDiagnoser() {}
8281
8282	virtual void diagnose(Sema &S, SourceLocation Loc, QualType T) = `0`;
8283	virtual ~TypeDiagnoser() {}
8284	};
8285
8286	template <typename... Ts> class BoundTypeDiagnoser : public TypeDiagnoser {
8287	protected:
8288	unsigned DiagID;
8289	std::tuple<const Ts &...> Args;
8290
8291	template <std::size_t... Is>
8292	void emit(const SemaDiagnosticBuilder &DB,
8293	std::index_sequence<Is...>) const {
8294	// Apply all tuple elements to the builder in order.
8295	bool Dummy[] = {false, (DB << getPrintable(std::get<Is>(Args)))...};
8296	(void)Dummy;
8297	}
8298
8299	public:
8300	BoundTypeDiagnoser(unsigned DiagID, const Ts &...Args)
8301	: TypeDiagnoser(), DiagID(DiagID), Args(Args...) {
8302	assert(DiagID != `0` && "no diagnostic for type diagnoser");
8303	}
8304
8305	void diagnose(Sema &S, SourceLocation Loc, QualType T) override {
8306	const SemaDiagnosticBuilder &DB = S.Diag(Loc, DiagID);
8307	emit(DB, std::index_sequence_for<Ts...>());
8308	DB << T;
8309	}
8310	};
8311
8312	/// A derivative of BoundTypeDiagnoser for which the diagnostic's type
8313	/// parameter is preceded by a 0/1 enum that is 1 if the type is sizeless.
8314	/// For example, a diagnostic with no other parameters would generally have
8315	/// the form "...%select{incomplete\|sizeless}0 type %1...".
8316	template <typename... Ts>
8317	class SizelessTypeDiagnoser : public BoundTypeDiagnoser<Ts...> {
8318	public:
8319	SizelessTypeDiagnoser(unsigned DiagID, const Ts &...Args)
8320	: BoundTypeDiagnoser<Ts...>(DiagID, Args...) {}
8321
8322	void diagnose(Sema &S, SourceLocation Loc, QualType T) override {
8323	const SemaDiagnosticBuilder &DB = S.Diag(Loc, this->DiagID);
8324	this->emit(DB, std::index_sequence_for<Ts...>());
8325	DB << T ->isSizelessType() << T;
8326	}
8327	};
8328
8329	/// Check an argument list for placeholders that we won't try to
8330	/// handle later.
8331	bool CheckArgsForPlaceholders(MultiExprArg args);
8332
8333	/// The C++ "std::source_location::__impl" struct, defined in
8334	/// \<source_location>.
8335	RecordDecl *StdSourceLocationImplDecl;
8336
8337	/// A stack of expression evaluation contexts.
8338	SmallVector<ExpressionEvaluationContextRecord, `8`> ExprEvalContexts;
8339
8340	// Set of failed immediate invocations to avoid double diagnosing.
8341	llvm::SmallPtrSet<ConstantExpr *, `4`> FailedImmediateInvocations;
8342
8343	/// List of SourceLocations where 'self' is implicitly retained inside a
8344	/// block.
8345	llvm::SmallVector<std::pair<SourceLocation, const BlockDecl *>, `1`>
8346	ImplicitlyRetainedSelfLocs;
8347
8348	/// Do an explicit extend of the given block pointer if we're in ARC.
8349	void maybeExtendBlockObject(ExprResult &E);
8350
8351	std::vector<std::pair<QualType, unsigned>> ExcessPrecisionNotSatisfied;
8352	SourceLocation LocationOfExcessPrecisionNotSatisfied;
8353	void DiagnosePrecisionLossInComplexDivision();
8354
8355	private:
8356	static BinaryOperatorKind ConvertTokenKindToBinaryOpcode(tok::TokenKind Kind);
8357
8358	/// Methods for marking which expressions involve dereferencing a pointer
8359	/// marked with the 'noderef' attribute. Expressions are checked bottom up as
8360	/// they are parsed, meaning that a noderef pointer may not be accessed. For
8361	/// example, in `&p` where `p` is a noderef pointer, we will first parse the*
8362	/// `p`, but need to check that `address of` is called on it. This requires*
8363	/// keeping a container of all pending expressions and checking if the address
8364	/// of them are eventually taken.
8365	void CheckSubscriptAccessOfNoDeref(const ArraySubscriptExpr *E);
8366	void CheckAddressOfNoDeref(const Expr *E);
8367
8368	///@}
8369
8370	//
8371	//
8372	// -------------------------------------------------------------------------
8373	//
8374	//
8375
8376	/// \name C++ Expressions
8377	/// Implementations are in SemaExprCXX.cpp
8378	///@{
8379
8380	public:
8381	/// The C++ "std::bad_alloc" class, which is defined by the C++
8382	/// standard library.
8383	LazyDeclPtr StdBadAlloc;
8384
8385	/// The C++ "std::align_val_t" enum class, which is defined by the C++
8386	/// standard library.
8387	LazyDeclPtr StdAlignValT;
8388
8389	/// The C++ "type_info" declaration, which is defined in \<typeinfo>.
8390	RecordDecl *CXXTypeInfoDecl;
8391
8392	/// A flag to remember whether the implicit forms of operator new and delete
8393	/// have been declared.
8394	bool GlobalNewDeleteDeclared;
8395
8396	/// Delete-expressions to be analyzed at the end of translation unit
8397	///
8398	/// This list contains class members, and locations of delete-expressions
8399	/// that could not be proven as to whether they mismatch with new-expression
8400	/// used in initializer of the field.
8401	llvm::MapVector<FieldDecl *, DeleteLocs> DeleteExprs;
8402
8403	/// Handle the result of the special case name lookup for inheriting
8404	/// constructor declarations. 'NS::X::X' and 'NS::X<...>::X' are treated as
8405	/// constructor names in member using declarations, even if 'X' is not the
8406	/// name of the corresponding type.
8407	ParsedType getInheritingConstructorName(CXXScopeSpec &SS,
8408	SourceLocation NameLoc,
8409	const IdentifierInfo &Name);
8410
8411	ParsedType getConstructorName(const IdentifierInfo &II,
8412	SourceLocation NameLoc, Scope *S,
8413	CXXScopeSpec &SS, bool EnteringContext);
8414	ParsedType getDestructorName(const IdentifierInfo &II, SourceLocation NameLoc,
8415	Scope *S, CXXScopeSpec &SS,
8416	ParsedType ObjectType, bool EnteringContext);
8417
8418	ParsedType getDestructorTypeForDecltype(const DeclSpec &DS,
8419	ParsedType ObjectType);
8420
8421	/// Build a C++ typeid expression with a type operand.
8422	ExprResult BuildCXXTypeId(QualType TypeInfoType, SourceLocation TypeidLoc,
8423	TypeSourceInfo *Operand, SourceLocation RParenLoc);
8424
8425	/// Build a C++ typeid expression with an expression operand.
8426	ExprResult BuildCXXTypeId(QualType TypeInfoType, SourceLocation TypeidLoc,
8427	Expr *Operand, SourceLocation RParenLoc);
8428
8429	/// ActOnCXXTypeid - Parse typeid( something ).
8430	ExprResult ActOnCXXTypeid(SourceLocation OpLoc, SourceLocation LParenLoc,
8431	bool isType, void *TyOrExpr,
8432	SourceLocation RParenLoc);
8433
8434	/// Build a Microsoft __uuidof expression with a type operand.
8435	ExprResult BuildCXXUuidof(QualType TypeInfoType, SourceLocation TypeidLoc,
8436	TypeSourceInfo *Operand, SourceLocation RParenLoc);
8437
8438	/// Build a Microsoft __uuidof expression with an expression operand.
8439	ExprResult BuildCXXUuidof(QualType TypeInfoType, SourceLocation TypeidLoc,
8440	Expr *Operand, SourceLocation RParenLoc);
8441
8442	/// ActOnCXXUuidof - Parse __uuidof( something ).
8443	ExprResult ActOnCXXUuidof(SourceLocation OpLoc, SourceLocation LParenLoc,
8444	bool isType, void *TyOrExpr,
8445	SourceLocation RParenLoc);
8446
8447	//// ActOnCXXThis - Parse 'this' pointer.
8448	ExprResult ActOnCXXThis(SourceLocation Loc);
8449
8450	/// Check whether the type of 'this' is valid in the current context.
8451	bool CheckCXXThisType(SourceLocation Loc, QualType Type);
8452
8453	/// Build a CXXThisExpr and mark it referenced in the current context.
8454	Expr BuildCXXThisExpr(SourceLocation Loc, QualType Type, bool* IsImplicit);
8455	void MarkThisReferenced(CXXThisExpr *This);
8456
8457	/// Try to retrieve the type of the 'this' pointer.
8458	///
8459	/// \returns The type of 'this', if possible. Otherwise, returns a NULL type.
8460	QualType getCurrentThisType();
8461
8462	/// When non-NULL, the C++ 'this' expression is allowed despite the
8463	/// current context not being a non-static member function. In such cases,
8464	/// this provides the type used for 'this'.
8465	QualType CXXThisTypeOverride;
8466
8467	/// RAII object used to temporarily allow the C++ 'this' expression
8468	/// to be used, with the given qualifiers on the current class type.
8469	class CXXThisScopeRAII {
8470	Sema &S;
8471	QualType OldCXXThisTypeOverride;
8472	bool Enabled;
8473
8474	public:
8475	/// Introduce a new scope where 'this' may be allowed (when enabled),
8476	/// using the given declaration (which is either a class template or a
8477	/// class) along with the given qualifiers.
8478	/// along with the qualifiers placed on 'this'.*
8479	CXXThisScopeRAII(Sema &S, Decl *ContextDecl, Qualifiers CXXThisTypeQuals,
8480	bool Enabled = true);
8481
8482	~CXXThisScopeRAII();
8483	CXXThisScopeRAII(const CXXThisScopeRAII &) = delete;
8484	CXXThisScopeRAII &operator=(const CXXThisScopeRAII &) = delete;
8485	};
8486
8487	/// Make sure the value of 'this' is actually available in the current
8488	/// context, if it is a potentially evaluated context.
8489	///
8490	/// \param Loc The location at which the capture of 'this' occurs.
8491	///
8492	/// \param Explicit Whether 'this' is explicitly captured in a lambda
8493	/// capture list.
8494	///
8495	/// \param FunctionScopeIndexToStopAt If non-null, it points to the index
8496	/// of the FunctionScopeInfo stack beyond which we do not attempt to capture.
8497	/// This is useful when enclosing lambdas must speculatively capture
8498	/// 'this' that may or may not be used in certain specializations of
8499	/// a nested generic lambda (depending on whether the name resolves to
8500	/// a non-static member function or a static function).
8501	/// \return returns 'true' if failed, 'false' if success.
8502	bool CheckCXXThisCapture(
8503	SourceLocation Loc, bool Explicit = false, bool BuildAndDiagnose = true,
8504	const unsigned *const FunctionScopeIndexToStopAt = nullptr,
8505	bool ByCopy = false);
8506
8507	/// Determine whether the given type is the type of this that is used*
8508	/// outside of the body of a member function for a type that is currently
8509	/// being defined.
8510	bool isThisOutsideMemberFunctionBody(QualType BaseType);
8511
8512	/// ActOnCXXBoolLiteral - Parse {true,false} literals.
8513	ExprResult ActOnCXXBoolLiteral(SourceLocation OpLoc, tok::TokenKind Kind);
8514
8515	/// Build a boolean-typed literal expression.
8516	ExprResult BuildBoolLiteral(SourceLocation Loc, bool Value);
8517
8518	/// ActOnCXXNullPtrLiteral - Parse 'nullptr'.
8519	ExprResult ActOnCXXNullPtrLiteral(SourceLocation Loc);
8520
8521	//// ActOnCXXThrow - Parse throw expressions.
8522	ExprResult ActOnCXXThrow(Scope S, SourceLocation OpLoc, Expr expr);
8523	ExprResult BuildCXXThrow(SourceLocation OpLoc, Expr *Ex,
8524	bool IsThrownVarInScope);
8525
8526	/// CheckCXXThrowOperand - Validate the operand of a throw.
8527	bool CheckCXXThrowOperand(SourceLocation ThrowLoc, QualType ThrowTy, Expr *E);
8528
8529	/// ActOnCXXTypeConstructExpr - Parse construction of a specified type.
8530	/// Can be interpreted either as function-style casting ("int(x)")
8531	/// or class type construction ("ClassType(x,y,z)")
8532	/// or creation of a value-initialized type ("int()").
8533	ExprResult ActOnCXXTypeConstructExpr(ParsedType TypeRep,
8534	SourceLocation LParenOrBraceLoc,
8535	MultiExprArg Exprs,
8536	SourceLocation RParenOrBraceLoc,
8537	bool ListInitialization);
8538
8539	ExprResult BuildCXXTypeConstructExpr(TypeSourceInfo *Type,
8540	SourceLocation LParenLoc,
8541	MultiExprArg Exprs,
8542	SourceLocation RParenLoc,
8543	bool ListInitialization);
8544
8545	/// Parsed a C++ 'new' expression (C++ 5.3.4).
8546	///
8547	/// E.g.:
8548	/// @code new (memory) int[size][4] @endcode
8549	/// or
8550	/// @code ::new Foo(23, "hello") @endcode
8551	///
8552	/// \param StartLoc The first location of the expression.
8553	/// \param UseGlobal True if 'new' was prefixed with '::'.
8554	/// \param PlacementLParen Opening paren of the placement arguments.
8555	/// \param PlacementArgs Placement new arguments.
8556	/// \param PlacementRParen Closing paren of the placement arguments.
8557	/// \param TypeIdParens If the type is in parens, the source range.
8558	/// \param D The type to be allocated, as well as array dimensions.
8559	/// \param Initializer The initializing expression or initializer-list, or
8560	/// null if there is none.
8561	ExprResult ActOnCXXNew(SourceLocation StartLoc, bool UseGlobal,
8562	SourceLocation PlacementLParen,
8563	MultiExprArg PlacementArgs,
8564	SourceLocation PlacementRParen,
8565	SourceRange TypeIdParens, Declarator &D,
8566	Expr *Initializer);
8567	ExprResult
8568	BuildCXXNew(SourceRange Range, bool UseGlobal, SourceLocation PlacementLParen,
8569	MultiExprArg PlacementArgs, SourceLocation PlacementRParen,
8570	SourceRange TypeIdParens, QualType AllocType,
8571	TypeSourceInfo AllocTypeInfo, std::optional<Expr > ArraySize,
8572	SourceRange DirectInitRange, Expr *Initializer);
8573
8574	/// Determine whether \p FD is an aligned allocation or deallocation
8575	/// function that is unavailable.
8576	bool isUnavailableAlignedAllocationFunction(const FunctionDecl &FD) const;
8577
8578	/// Produce diagnostics if \p FD is an aligned allocation or deallocation
8579	/// function that is unavailable.
8580	void diagnoseUnavailableAlignedAllocation(const FunctionDecl &FD,
8581	SourceLocation Loc);
8582
8583	/// Checks that a type is suitable as the allocated type
8584	/// in a new-expression.
8585	bool CheckAllocatedType(QualType AllocType, SourceLocation Loc,
8586	SourceRange R);
8587
8588	/// Finds the overloads of operator new and delete that are appropriate
8589	/// for the allocation.
8590	std::optional<ResolvedAllocation> FindAllocationFunctions(
8591	SourceLocation StartLoc, SourceRange Range,
8592	AllocationFunctionScope NewScope, AllocationFunctionScope DeleteScope,
8593	QualType AllocType, bool IsArray, const ImplicitAllocationParameters &IAP,
8594	MultiExprArg PlaceArgs, bool Diagnose = true);
8595
8596	/// DeclareGlobalNewDelete - Declare the global forms of operator new and
8597	/// delete. These are:
8598	/// @code
8599	/// // C++03:
8600	/// void operator new(std::size_t) throw(std::bad_alloc);*
8601	/// void operator new[](std::size_t) throw(std::bad_alloc);*
8602	/// void operator delete(void ) throw();*
8603	/// void operator delete[](void ) throw();*
8604	/// // C++11:
8605	/// void operator new(std::size_t);*
8606	/// void operator new[](std::size_t);*
8607	/// void operator delete(void ) noexcept;*
8608	/// void operator delete[](void ) noexcept;*
8609	/// // C++1y:
8610	/// void operator new(std::size_t);*
8611	/// void operator new[](std::size_t);*
8612	/// void operator delete(void ) noexcept;*
8613	/// void operator delete[](void ) noexcept;*
8614	/// void operator delete(void , std::size_t) noexcept;*
8615	/// void operator delete[](void , std::size_t) noexcept;*
8616	/// @endcode
8617	/// Note that the placement and nothrow forms of new are not* implicitly*
8618	/// declared. Their use requires including \<new\>.
8619	void DeclareGlobalNewDelete();
8620	void DeclareGlobalAllocationFunction(DeclarationName Name, QualType Return,
8621	ArrayRef<QualType> Params);
8622
8623	bool FindDeallocationFunction(SourceLocation StartLoc, CXXRecordDecl *RD,
8624	DeclarationName Name, FunctionDecl *&Operator,
8625	ImplicitDeallocationParameters,
8626	bool Diagnose = true);
8627	FunctionDecl *FindUsualDeallocationFunction(SourceLocation StartLoc,
8628	ImplicitDeallocationParameters,
8629	DeclarationName Name,
8630	bool Diagnose = true);
8631	FunctionDecl *FindDeallocationFunctionForDestructor(SourceLocation StartLoc,
8632	CXXRecordDecl *RD,
8633	bool Diagnose,
8634	bool LookForGlobal,
8635	DeclarationName Name);
8636
8637	/// ActOnCXXDelete - Parsed a C++ 'delete' expression (C++ 5.3.5), as in:
8638	/// @code ::delete ptr; @endcode
8639	/// or
8640	/// @code delete [] ptr; @endcode
8641	ExprResult ActOnCXXDelete(SourceLocation StartLoc, bool UseGlobal,
8642	bool ArrayForm, Expr *Operand);
8643	void CheckVirtualDtorCall(CXXDestructorDecl *dtor, SourceLocation Loc,
8644	bool IsDelete, bool CallCanBeVirtual,
8645	bool WarnOnNonAbstractTypes,
8646	SourceLocation DtorLoc);
8647
8648	ExprResult ActOnNoexceptExpr(SourceLocation KeyLoc, SourceLocation LParen,
8649	Expr *Operand, SourceLocation RParen);
8650	ExprResult BuildCXXNoexceptExpr(SourceLocation KeyLoc, Expr *Operand,
8651	SourceLocation RParen);
8652
8653	ExprResult ActOnStartCXXMemberReference(Scope S, Expr Base,
8654	SourceLocation OpLoc,
8655	tok::TokenKind OpKind,
8656	ParsedType &ObjectType,
8657	bool &MayBePseudoDestructor);
8658
8659	ExprResult BuildPseudoDestructorExpr(
8660	Expr *Base, SourceLocation OpLoc, tok::TokenKind OpKind,
8661	const CXXScopeSpec &SS, TypeSourceInfo *ScopeType, SourceLocation CCLoc,
8662	SourceLocation TildeLoc, PseudoDestructorTypeStorage DestroyedType);
8663
8664	ExprResult ActOnPseudoDestructorExpr(
8665	Scope S, Expr Base, SourceLocation OpLoc, tok::TokenKind OpKind,
8666	CXXScopeSpec &SS, UnqualifiedId &FirstTypeName, SourceLocation CCLoc,
8667	SourceLocation TildeLoc, UnqualifiedId &SecondTypeName);
8668
8669	ExprResult ActOnPseudoDestructorExpr(Scope S, Expr Base,
8670	SourceLocation OpLoc,
8671	tok::TokenKind OpKind,
8672	SourceLocation TildeLoc,
8673	const DeclSpec &DS);
8674
8675	/// MaybeCreateExprWithCleanups - If the current full-expression
8676	/// requires any cleanups, surround it with a ExprWithCleanups node.
8677	/// Otherwise, just returns the passed-in expression.
8678	Expr MaybeCreateExprWithCleanups(Expr SubExpr);
8679	Stmt MaybeCreateStmtWithCleanups(Stmt SubStmt);
8680	ExprResult MaybeCreateExprWithCleanups(ExprResult SubExpr);
8681
8682	ExprResult ActOnFinishFullExpr(Expr Expr, bool* DiscardedValue) {
8683	return ActOnFinishFullExpr(
8684	Expr, CC: Expr ? Expr->getExprLoc() : SourceLocation (), DiscardedValue);
8685	}
8686	ExprResult ActOnFinishFullExpr(Expr *Expr, SourceLocation CC,
8687	bool DiscardedValue, bool IsConstexpr = false,
8688	bool IsTemplateArgument = false);
8689	StmtResult ActOnFinishFullStmt(Stmt *Stmt);
8690
8691	/// Process the expression contained within a decltype. For such expressions,
8692	/// certain semantic checks on temporaries are delayed until this point, and
8693	/// are omitted for the 'topmost' call in the decltype expression. If the
8694	/// topmost call bound a temporary, strip that temporary off the expression.
8695	ExprResult ActOnDecltypeExpression(Expr *E);
8696
8697	bool checkLiteralOperatorId(const CXXScopeSpec &SS, const UnqualifiedId &Id,
8698	bool IsUDSuffix);
8699
8700	bool isUsualDeallocationFunction(const CXXMethodDecl *FD);
8701
8702	ConditionResult ActOnConditionVariable(Decl *ConditionVar,
8703	SourceLocation StmtLoc,
8704	ConditionKind CK);
8705
8706	/// Check the use of the given variable as a C++ condition in an if,
8707	/// while, do-while, or switch statement.
8708	ExprResult CheckConditionVariable(VarDecl *ConditionVar,
8709	SourceLocation StmtLoc, ConditionKind CK);
8710
8711	/// CheckCXXBooleanCondition - Returns true if conversion to bool is invalid.
8712	ExprResult CheckCXXBooleanCondition(Expr CondExpr, bool* IsConstexpr = false);
8713
8714	/// Helper function to determine whether this is the (deprecated) C++
8715	/// conversion from a string literal to a pointer to non-const char or
8716	/// non-const wchar_t (for narrow and wide string literals,
8717	/// respectively).
8718	bool IsStringLiteralToNonConstPointerConversion(Expr *From, QualType ToType);
8719
8720	/// PerformImplicitConversion - Perform an implicit conversion of the
8721	/// expression From to the type ToType using the pre-computed implicit
8722	/// conversion sequence ICS. Returns the converted
8723	/// expression. Action is the kind of conversion we're performing,
8724	/// used in the error message.
8725	ExprResult PerformImplicitConversion(
8726	Expr From, QualType ToType, const* ImplicitConversionSequence &ICS,
8727	AssignmentAction Action,
8728	CheckedConversionKind CCK = CheckedConversionKind::Implicit);
8729
8730	/// PerformImplicitConversion - Perform an implicit conversion of the
8731	/// expression From to the type ToType by following the standard
8732	/// conversion sequence SCS. Returns the converted
8733	/// expression. Flavor is the context in which we're performing this
8734	/// conversion, for use in error messages.
8735	ExprResult PerformImplicitConversion(Expr *From, QualType ToType,
8736	const StandardConversionSequence &SCS,
8737	AssignmentAction Action,
8738	CheckedConversionKind CCK);
8739
8740	bool CheckTypeTraitArity(unsigned Arity, SourceLocation Loc, size_t N);
8741
8742	/// Parsed one of the type trait support pseudo-functions.
8743	ExprResult ActOnTypeTrait(TypeTrait Kind, SourceLocation KWLoc,
8744	ArrayRef<ParsedType> Args,
8745	SourceLocation RParenLoc);
8746	ExprResult BuildTypeTrait(TypeTrait Kind, SourceLocation KWLoc,
8747	ArrayRef<TypeSourceInfo *> Args,
8748	SourceLocation RParenLoc);
8749
8750	/// ActOnArrayTypeTrait - Parsed one of the binary type trait support
8751	/// pseudo-functions.
8752	ExprResult ActOnArrayTypeTrait(ArrayTypeTrait ATT, SourceLocation KWLoc,
8753	ParsedType LhsTy, Expr *DimExpr,
8754	SourceLocation RParen);
8755
8756	ExprResult BuildArrayTypeTrait(ArrayTypeTrait ATT, SourceLocation KWLoc,
8757	TypeSourceInfo TSInfo, Expr DimExpr,
8758	SourceLocation RParen);
8759
8760	/// ActOnExpressionTrait - Parsed one of the unary type trait support
8761	/// pseudo-functions.
8762	ExprResult ActOnExpressionTrait(ExpressionTrait OET, SourceLocation KWLoc,
8763	Expr *Queried, SourceLocation RParen);
8764
8765	ExprResult BuildExpressionTrait(ExpressionTrait OET, SourceLocation KWLoc,
8766	Expr *Queried, SourceLocation RParen);
8767
8768	QualType CheckPointerToMemberOperands( // C++ 5.5
8769	ExprResult &LHS, ExprResult &RHS, ExprValueKind &VK, SourceLocation OpLoc,
8770	bool isIndirect);
8771	QualType CheckVectorConditionalTypes(ExprResult &Cond, ExprResult &LHS,
8772	ExprResult &RHS,
8773	SourceLocation QuestionLoc);
8774
8775	//// Determines if a type is trivially relocatable
8776	/// according to the C++26 rules.
8777	// FIXME: This is in Sema because it requires
8778	// overload resolution, can we move to ASTContext?
8779	bool IsCXXTriviallyRelocatableType(QualType T);
8780	bool IsCXXTriviallyRelocatableType(const CXXRecordDecl &RD);
8781
8782	/// Check the operands of ?: under C++ semantics.
8783	///
8784	/// See C++ [expr.cond]. Note that LHS is never null, even for the GNU x ?: y
8785	/// extension. In this case, LHS == Cond. (But they're not aliases.)
8786	///
8787	/// This function also implements GCC's vector extension and the
8788	/// OpenCL/ext_vector_type extension for conditionals. The vector extensions
8789	/// permit the use of a?b:c where the type of a is that of a integer vector
8790	/// with the same number of elements and size as the vectors of b and c. If
8791	/// one of either b or c is a scalar it is implicitly converted to match the
8792	/// type of the vector. Otherwise the expression is ill-formed. If both b and
8793	/// c are scalars, then b and c are checked and converted to the type of a if
8794	/// possible.
8795	///
8796	/// The expressions are evaluated differently for GCC's and OpenCL's
8797	/// extensions. For the GCC extension, the ?: operator is evaluated as
8798	/// (a[0] != 0 ? b[0] : c[0], .. , a[n] != 0 ? b[n] : c[n]).
8799	/// For the OpenCL extensions, the ?: operator is evaluated as
8800	/// (most-significant-bit-set(a[0]) ? b[0] : c[0], .. ,
8801	/// most-significant-bit-set(a[n]) ? b[n] : c[n]).
8802	QualType CXXCheckConditionalOperands( // C++ 5.16
8803	ExprResult &cond, ExprResult &lhs, ExprResult &rhs, ExprValueKind &VK,
8804	ExprObjectKind &OK, SourceLocation questionLoc);
8805
8806	/// Find a merged pointer type and convert the two expressions to it.
8807	///
8808	/// This finds the composite pointer type for \p E1 and \p E2 according to
8809	/// C++2a [expr.type]p3. It converts both expressions to this type and returns
8810	/// it. It does not emit diagnostics (FIXME: that's not true if \p
8811	/// ConvertArgs is \c true).
8812	///
8813	/// \param Loc The location of the operator requiring these two expressions to
8814	/// be converted to the composite pointer type.
8815	///
8816	/// \param ConvertArgs If \c false, do not convert E1 and E2 to the target
8817	/// type.
8818	QualType FindCompositePointerType(SourceLocation Loc, Expr &E1, Expr &E2,
8819	bool ConvertArgs = true);
8820	QualType FindCompositePointerType(SourceLocation Loc, ExprResult &E1,
8821	ExprResult &E2, bool ConvertArgs = true) {
8822	Expr E1Tmp = E1.get(), E2Tmp = E2.get();
8823	QualType Composite =
8824	FindCompositePointerType(Loc, E1&: E1Tmp, E2&: E2Tmp, ConvertArgs);
8825	E1 = E1Tmp;
8826	E2 = E2Tmp;
8827	return Composite;
8828	}
8829
8830	/// MaybeBindToTemporary - If the passed in expression has a record type with
8831	/// a non-trivial destructor, this will return CXXBindTemporaryExpr. Otherwise
8832	/// it simply returns the passed in expression.
8833	ExprResult MaybeBindToTemporary(Expr *E);
8834
8835	/// IgnoredValueConversions - Given that an expression's result is
8836	/// syntactically ignored, perform any conversions that are
8837	/// required.
8838	ExprResult IgnoredValueConversions(Expr *E);
8839
8840	ExprResult CheckUnevaluatedOperand(Expr *E);
8841
8842	IfExistsResult
8843	CheckMicrosoftIfExistsSymbol(Scope *S, CXXScopeSpec &SS,
8844	const DeclarationNameInfo &TargetNameInfo);
8845
8846	IfExistsResult CheckMicrosoftIfExistsSymbol(Scope *S,
8847	SourceLocation KeywordLoc,
8848	bool IsIfExists, CXXScopeSpec &SS,
8849	UnqualifiedId &Name);
8850
8851	RequiresExprBodyDecl *
8852	ActOnStartRequiresExpr(SourceLocation RequiresKWLoc,
8853	ArrayRef<ParmVarDecl *> LocalParameters,
8854	Scope *BodyScope);
8855	void ActOnFinishRequiresExpr();
8856	concepts::Requirement ActOnSimpleRequirement(Expr E);
8857	concepts::Requirement *ActOnTypeRequirement(SourceLocation TypenameKWLoc,
8858	CXXScopeSpec &SS,
8859	SourceLocation NameLoc,
8860	const IdentifierInfo *TypeName,
8861	TemplateIdAnnotation *TemplateId);
8862	concepts::Requirement ActOnCompoundRequirement(Expr E,
8863	SourceLocation NoexceptLoc);
8864	concepts::Requirement *ActOnCompoundRequirement(
8865	Expr *E, SourceLocation NoexceptLoc, CXXScopeSpec &SS,
8866	TemplateIdAnnotation TypeConstraint, unsigned* Depth);
8867	concepts::Requirement ActOnNestedRequirement(Expr Constraint);
8868	concepts::ExprRequirement *BuildExprRequirement(
8869	Expr E, bool* IsSatisfied, SourceLocation NoexceptLoc,
8870	concepts::ExprRequirement::ReturnTypeRequirement ReturnTypeRequirement);
8871	concepts::ExprRequirement *BuildExprRequirement(
8872	concepts::Requirement::SubstitutionDiagnostic *ExprSubstDiag,
8873	bool IsSatisfied, SourceLocation NoexceptLoc,
8874	concepts::ExprRequirement::ReturnTypeRequirement ReturnTypeRequirement);
8875	concepts::TypeRequirement BuildTypeRequirement(TypeSourceInfo Type);
8876	concepts::TypeRequirement *BuildTypeRequirement(
8877	concepts::Requirement::SubstitutionDiagnostic *SubstDiag);
8878	concepts::NestedRequirement BuildNestedRequirement(Expr E);
8879	concepts::NestedRequirement *
8880	BuildNestedRequirement(StringRef InvalidConstraintEntity,
8881	const ASTConstraintSatisfaction &Satisfaction);
8882	ExprResult ActOnRequiresExpr(SourceLocation RequiresKWLoc,
8883	RequiresExprBodyDecl *Body,
8884	SourceLocation LParenLoc,
8885	ArrayRef<ParmVarDecl *> LocalParameters,
8886	SourceLocation RParenLoc,
8887	ArrayRef<concepts::Requirement *> Requirements,
8888	SourceLocation ClosingBraceLoc);
8889
8890	private:
8891	ExprResult BuiltinOperatorNewDeleteOverloaded(ExprResult TheCallResult,
8892	bool IsDelete);
8893
8894	void AnalyzeDeleteExprMismatch(const CXXDeleteExpr *DE);
8895	void AnalyzeDeleteExprMismatch(FieldDecl *Field, SourceLocation DeleteLoc,
8896	bool DeleteWasArrayForm);
8897
8898	std::optional<AllocationArgumentSet>
8899	resolveAllocationArguments(LookupResult &R,
8900	const ImplicitAllocationParameters &,
8901	ArrayRef<Expr *> PlacementArguments);
8902
8903	// Attempts to construct the type identity argument for the call to a
8904	// type aware operator new. Returns null on failure.
8905	Expr *tryGetTypeIdentityArgument(QualType Type, SourceLocation);
8906
8907	Expr AllocationSizeExpr = nullptr*;
8908	Expr AllocationAlignmentExpr = nullptr*;
8909	llvm::DenseMap<QualType, Expr *> AllocationTypeIdentityArguments;
8910
8911	///@}
8912
8913	//
8914	//
8915	// -------------------------------------------------------------------------
8916	//
8917	//
8918
8919	/// \name Member Access Expressions
8920	/// Implementations are in SemaExprMember.cpp
8921	///@{
8922
8923	public:
8924	/// Check whether an expression might be an implicit class member access.
8925	bool isPotentialImplicitMemberAccess(const CXXScopeSpec &SS, LookupResult &R,
8926	bool IsAddressOfOperand);
8927
8928	/// Builds an expression which might be an implicit member expression.
8929	ExprResult BuildPossibleImplicitMemberExpr(
8930	const CXXScopeSpec &SS, SourceLocation TemplateKWLoc, LookupResult &R,
8931	const TemplateArgumentListInfo TemplateArgs, const* Scope *S);
8932
8933	/// Builds an implicit member access expression. The current context
8934	/// is known to be an instance method, and the given unqualified lookup
8935	/// set is known to contain only instance members, at least one of which
8936	/// is from an appropriate type.
8937	ExprResult
8938	BuildImplicitMemberExpr(const CXXScopeSpec &SS, SourceLocation TemplateKWLoc,
8939	LookupResult &R,
8940	const TemplateArgumentListInfo *TemplateArgs,
8941	bool IsDefiniteInstance, const Scope *S);
8942
8943	ExprResult ActOnDependentMemberExpr(
8944	Expr Base, QualType BaseType, bool* IsArrow, SourceLocation OpLoc,
8945	const CXXScopeSpec &SS, SourceLocation TemplateKWLoc,
8946	NamedDecl FirstQualifierInScope, const* DeclarationNameInfo &NameInfo,
8947	const TemplateArgumentListInfo *TemplateArgs);
8948
8949	/// The main callback when the parser finds something like
8950	/// expression . [nested-name-specifier] identifier
8951	/// expression -> [nested-name-specifier] identifier
8952	/// where 'identifier' encompasses a fairly broad spectrum of
8953	/// possibilities, including destructor and operator references.
8954	///
8955	/// \param OpKind either tok::arrow or tok::period
8956	/// \param ObjCImpDecl the current Objective-C \@implementation
8957	/// decl; this is an ugly hack around the fact that Objective-C
8958	/// \@implementations aren't properly put in the context chain
8959	ExprResult ActOnMemberAccessExpr(Scope S, Expr Base, SourceLocation OpLoc,
8960	tok::TokenKind OpKind, CXXScopeSpec &SS,
8961	SourceLocation TemplateKWLoc,
8962	UnqualifiedId &Member, Decl *ObjCImpDecl);
8963
8964	MemberExpr *
8965	BuildMemberExpr(Expr Base, bool* IsArrow, SourceLocation OpLoc,
8966	NestedNameSpecifierLoc NNS, SourceLocation TemplateKWLoc,
8967	ValueDecl *Member, DeclAccessPair FoundDecl,
8968	bool HadMultipleCandidates,
8969	const DeclarationNameInfo &MemberNameInfo, QualType Ty,
8970	ExprValueKind VK, ExprObjectKind OK,
8971	const TemplateArgumentListInfo TemplateArgs = nullptr*);
8972
8973	// Check whether the declarations we found through a nested-name
8974	// specifier in a member expression are actually members of the base
8975	// type. The restriction here is:
8976	//
8977	// C++ [expr.ref]p2:
8978	// ... In these cases, the id-expression shall name a
8979	// member of the class or of one of its base classes.
8980	//
8981	// So it's perfectly legitimate for the nested-name specifier to name
8982	// an unrelated class, and for us to find an overload set including
8983	// decls from classes which are not superclasses, as long as the decl
8984	// we actually pick through overload resolution is from a superclass.
8985	bool CheckQualifiedMemberReference(Expr *BaseExpr, QualType BaseType,
8986	const CXXScopeSpec &SS,
8987	const LookupResult &R);
8988
8989	// This struct is for use by ActOnMemberAccess to allow
8990	// BuildMemberReferenceExpr to be able to reinvoke ActOnMemberAccess after
8991	// changing the access operator from a '.' to a '->' (to see if that is the
8992	// change needed to fix an error about an unknown member, e.g. when the class
8993	// defines a custom operator->).
8994	struct ActOnMemberAccessExtraArgs {
8995	Scope *S;
8996	UnqualifiedId &Id;
8997	Decl *ObjCImpDecl;
8998	};
8999
9000	ExprResult BuildMemberReferenceExpr(
9001	Expr Base, QualType BaseType, SourceLocation OpLoc, bool* IsArrow,
9002	CXXScopeSpec &SS, SourceLocation TemplateKWLoc,
9003	NamedDecl FirstQualifierInScope, const* DeclarationNameInfo &NameInfo,
9004	const TemplateArgumentListInfo TemplateArgs, const* Scope *S,
9005	ActOnMemberAccessExtraArgs ExtraArgs = nullptr*);
9006
9007	ExprResult
9008	BuildMemberReferenceExpr(Expr *Base, QualType BaseType, SourceLocation OpLoc,
9009	bool IsArrow, const CXXScopeSpec &SS,
9010	SourceLocation TemplateKWLoc,
9011	NamedDecl *FirstQualifierInScope, LookupResult &R,
9012	const TemplateArgumentListInfo *TemplateArgs,
9013	const Scope S, bool* SuppressQualifierCheck = false,
9014	ActOnMemberAccessExtraArgs ExtraArgs = nullptr*);
9015
9016	ExprResult BuildFieldReferenceExpr(Expr BaseExpr, bool* IsArrow,
9017	SourceLocation OpLoc,
9018	const CXXScopeSpec &SS, FieldDecl *Field,
9019	DeclAccessPair FoundDecl,
9020	const DeclarationNameInfo &MemberNameInfo);
9021
9022	/// Perform conversions on the LHS of a member access expression.
9023	ExprResult PerformMemberExprBaseConversion(Expr Base, bool* IsArrow);
9024
9025	ExprResult BuildAnonymousStructUnionMemberReference(
9026	const CXXScopeSpec &SS, SourceLocation nameLoc,
9027	IndirectFieldDecl *indirectField,
9028	DeclAccessPair FoundDecl = DeclAccessPair::make(D: nullptr, AS: AS_none),
9029	Expr baseObjectExpr = nullptr*, SourceLocation opLoc = SourceLocation ());
9030
9031	private:
9032	void CheckMemberAccessOfNoDeref(const MemberExpr *E);
9033
9034	///@}
9035
9036	//
9037	//
9038	// -------------------------------------------------------------------------
9039	//
9040	//
9041
9042	/// \name Initializers
9043	/// Implementations are in SemaInit.cpp
9044	///@{
9045
9046	public:
9047	/// Stack of types that correspond to the parameter entities that are
9048	/// currently being copy-initialized. Can be empty.
9049	llvm::SmallVector<QualType, `4`> CurrentParameterCopyTypes;
9050
9051	llvm::DenseMap<unsigned, CXXDeductionGuideDecl *>
9052	AggregateDeductionCandidates;
9053
9054	bool IsStringInit(Expr Init, const* ArrayType *AT);
9055
9056	/// Determine whether we can perform aggregate initialization for the purposes
9057	/// of overload resolution.
9058	bool CanPerformAggregateInitializationForOverloadResolution(
9059	const InitializedEntity &Entity, InitListExpr *From);
9060
9061	ExprResult ActOnDesignatedInitializer(Designation &Desig,
9062	SourceLocation EqualOrColonLoc,
9063	bool GNUSyntax, ExprResult Init);
9064
9065	/// Check that the lifetime of the initializer (and its subobjects) is
9066	/// sufficient for initializing the entity, and perform lifetime extension
9067	/// (when permitted) if not.
9068	void checkInitializerLifetime(const InitializedEntity &Entity, Expr *Init);
9069
9070	MaterializeTemporaryExpr *
9071	CreateMaterializeTemporaryExpr(QualType T, Expr *Temporary,
9072	bool BoundToLvalueReference);
9073
9074	/// If \p E is a prvalue denoting an unmaterialized temporary, materialize
9075	/// it as an xvalue. In C++98, the result will still be a prvalue, because
9076	/// we don't have xvalues there.
9077	ExprResult TemporaryMaterializationConversion(Expr *E);
9078
9079	ExprResult PerformQualificationConversion(
9080	Expr *E, QualType Ty, ExprValueKind VK = VK_PRValue,
9081	CheckedConversionKind CCK = CheckedConversionKind::Implicit);
9082
9083	bool CanPerformCopyInitialization(const InitializedEntity &Entity,
9084	ExprResult Init);
9085	ExprResult PerformCopyInitialization(const InitializedEntity &Entity,
9086	SourceLocation EqualLoc, ExprResult Init,
9087	bool TopLevelOfInitList = false,
9088	bool AllowExplicit = false);
9089
9090	QualType DeduceTemplateSpecializationFromInitializer(
9091	TypeSourceInfo TInfo, const* InitializedEntity &Entity,
9092	const InitializationKind &Kind, MultiExprArg Init);
9093
9094	///@}
9095
9096	//
9097	//
9098	// -------------------------------------------------------------------------
9099	//
9100	//
9101
9102	/// \name C++ Lambda Expressions
9103	/// Implementations are in SemaLambda.cpp
9104	///@{
9105
9106	public:
9107	/// Create a new lambda closure type.
9108	CXXRecordDecl *createLambdaClosureType(SourceRange IntroducerRange,
9109	TypeSourceInfo *Info,
9110	unsigned LambdaDependencyKind,
9111	LambdaCaptureDefault CaptureDefault);
9112
9113	/// Number lambda for linkage purposes if necessary.
9114	void handleLambdaNumbering(CXXRecordDecl Class, CXXMethodDecl Method,
9115	std::optional<CXXRecordDecl::LambdaNumbering>
9116	NumberingOverride = std::nullopt);
9117
9118	/// Endow the lambda scope info with the relevant properties.
9119	void buildLambdaScope(sema::LambdaScopeInfo LSI, CXXMethodDecl CallOperator,
9120	SourceRange IntroducerRange,
9121	LambdaCaptureDefault CaptureDefault,
9122	SourceLocation CaptureDefaultLoc, bool ExplicitParams,
9123	bool Mutable);
9124
9125	CXXMethodDecl *CreateLambdaCallOperator(SourceRange IntroducerRange,
9126	CXXRecordDecl *Class);
9127
9128	void AddTemplateParametersToLambdaCallOperator(
9129	CXXMethodDecl CallOperator, CXXRecordDecl Class,
9130	TemplateParameterList *TemplateParams);
9131
9132	void
9133	CompleteLambdaCallOperator(CXXMethodDecl *Method, SourceLocation LambdaLoc,
9134	SourceLocation CallOperatorLoc,
9135	const AssociatedConstraint &TrailingRequiresClause,
9136	TypeSourceInfo *MethodTyInfo,
9137	ConstexprSpecKind ConstexprKind, StorageClass SC,
9138	ArrayRef<ParmVarDecl *> Params,
9139	bool HasExplicitResultType);
9140
9141	/// Returns true if the explicit object parameter was invalid.
9142	bool DiagnoseInvalidExplicitObjectParameterInLambda(CXXMethodDecl *Method,
9143	SourceLocation CallLoc);
9144
9145	/// Perform initialization analysis of the init-capture and perform
9146	/// any implicit conversions such as an lvalue-to-rvalue conversion if
9147	/// not being used to initialize a reference.
9148	ParsedType actOnLambdaInitCaptureInitialization(
9149	SourceLocation Loc, bool ByRef, SourceLocation EllipsisLoc,
9150	IdentifierInfo Id, LambdaCaptureInitKind InitKind, Expr &Init) {
9151	return ParsedType::make(P: buildLambdaInitCaptureInitialization(
9152	Loc, ByRef, EllipsisLoc, NumExpansions: std::nullopt, Id,
9153	DirectInit: InitKind != LambdaCaptureInitKind::CopyInit, Init));
9154	}
9155	QualType buildLambdaInitCaptureInitialization(SourceLocation Loc, bool ByRef,
9156	SourceLocation EllipsisLoc,
9157	UnsignedOrNone NumExpansions,
9158	IdentifierInfo *Id,
9159	bool DirectInit, Expr *&Init);
9160
9161	/// Create a dummy variable within the declcontext of the lambda's
9162	/// call operator, for name lookup purposes for a lambda init capture.
9163	///
9164	/// CodeGen handles emission of lambda captures, ignoring these dummy
9165	/// variables appropriately.
9166	VarDecl *createLambdaInitCaptureVarDecl(
9167	SourceLocation Loc, QualType InitCaptureType, SourceLocation EllipsisLoc,
9168	IdentifierInfo Id, unsigned* InitStyle, Expr Init, DeclContext DeclCtx);
9169
9170	/// Add an init-capture to a lambda scope.
9171	void addInitCapture(sema::LambdaScopeInfo LSI, VarDecl Var, bool ByRef);
9172
9173	/// Note that we have finished the explicit captures for the
9174	/// given lambda.
9175	void finishLambdaExplicitCaptures(sema::LambdaScopeInfo *LSI);
9176
9177	/// Deduce a block or lambda's return type based on the return
9178	/// statements present in the body.
9179	void deduceClosureReturnType(sema::CapturingScopeInfo &CSI);
9180
9181	/// Once the Lambdas capture are known, we can start to create the closure,
9182	/// call operator method, and keep track of the captures.
9183	/// We do the capture lookup here, but they are not actually captured until
9184	/// after we know what the qualifiers of the call operator are.
9185	void ActOnLambdaExpressionAfterIntroducer(LambdaIntroducer &Intro,
9186	Scope *CurContext);
9187
9188	/// This is called after parsing the explicit template parameter list
9189	/// on a lambda (if it exists) in C++2a.
9190	void ActOnLambdaExplicitTemplateParameterList(LambdaIntroducer &Intro,
9191	SourceLocation LAngleLoc,
9192	ArrayRef<NamedDecl *> TParams,
9193	SourceLocation RAngleLoc,
9194	ExprResult RequiresClause);
9195
9196	void ActOnLambdaClosureQualifiers(LambdaIntroducer &Intro,
9197	SourceLocation MutableLoc);
9198
9199	void ActOnLambdaClosureParameters(
9200	Scope *LambdaScope,
9201	MutableArrayRef<DeclaratorChunk::ParamInfo> ParamInfo);
9202
9203	/// ActOnStartOfLambdaDefinition - This is called just before we start
9204	/// parsing the body of a lambda; it analyzes the explicit captures and
9205	/// arguments, and sets up various data-structures for the body of the
9206	/// lambda.
9207	void ActOnStartOfLambdaDefinition(LambdaIntroducer &Intro,
9208	Declarator &ParamInfo, const DeclSpec &DS);
9209
9210	/// ActOnLambdaError - If there is an error parsing a lambda, this callback
9211	/// is invoked to pop the information about the lambda.
9212	void ActOnLambdaError(SourceLocation StartLoc, Scope *CurScope,
9213	bool IsInstantiation = false);
9214
9215	/// ActOnLambdaExpr - This is called when the body of a lambda expression
9216	/// was successfully completed.
9217	ExprResult ActOnLambdaExpr(SourceLocation StartLoc, Stmt *Body);
9218
9219	/// Does copying/destroying the captured variable have side effects?
9220	bool CaptureHasSideEffects(const sema::Capture &From);
9221
9222	/// Diagnose if an explicit lambda capture is unused. Returns true if a
9223	/// diagnostic is emitted.
9224	bool DiagnoseUnusedLambdaCapture(SourceRange CaptureRange,
9225	SourceRange FixItRange,
9226	const sema::Capture &From);
9227
9228	/// Build a FieldDecl suitable to hold the given capture.
9229	FieldDecl BuildCaptureField(RecordDecl RD, const sema::Capture &Capture);
9230
9231	/// Initialize the given capture with a suitable expression.
9232	ExprResult BuildCaptureInit(const sema::Capture &Capture,
9233	SourceLocation ImplicitCaptureLoc,
9234	bool IsOpenMPMapping = false);
9235
9236	/// Complete a lambda-expression having processed and attached the
9237	/// lambda body.
9238	ExprResult BuildLambdaExpr(SourceLocation StartLoc, SourceLocation EndLoc);
9239
9240	/// Get the return type to use for a lambda's conversion function(s) to
9241	/// function pointer type, given the type of the call operator.
9242	QualType
9243	getLambdaConversionFunctionResultType(const FunctionProtoType *CallOpType,
9244	CallingConv CC);
9245
9246	ExprResult BuildBlockForLambdaConversion(SourceLocation CurrentLocation,
9247	SourceLocation ConvLocation,
9248	CXXConversionDecl Conv, Expr Src);
9249
9250	class LambdaScopeForCallOperatorInstantiationRAII
9251	: private FunctionScopeRAII {
9252	public:
9253	LambdaScopeForCallOperatorInstantiationRAII(
9254	Sema &SemasRef, FunctionDecl *FD, MultiLevelTemplateArgumentList MLTAL,
9255	LocalInstantiationScope &Scope,
9256	bool ShouldAddDeclsFromParentScope = true);
9257	};
9258
9259	/// Compute the mangling number context for a lambda expression or
9260	/// block literal. Also return the extra mangling decl if any.
9261	///
9262	/// \param DC - The DeclContext containing the lambda expression or
9263	/// block literal.
9264	std::tuple<MangleNumberingContext , Decl >
9265	getCurrentMangleNumberContext(const DeclContext *DC);
9266
9267	///@}
9268
9269	//
9270	//
9271	// -------------------------------------------------------------------------
9272	//
9273	//
9274
9275	/// \name Name Lookup
9276	///
9277	/// These routines provide name lookup that is used during semantic
9278	/// analysis to resolve the various kinds of names (identifiers,
9279	/// overloaded operator names, constructor names, etc.) into zero or
9280	/// more declarations within a particular scope. The major entry
9281	/// points are LookupName, which performs unqualified name lookup,
9282	/// and LookupQualifiedName, which performs qualified name lookup.
9283	///
9284	/// All name lookup is performed based on some specific criteria,
9285	/// which specify what names will be visible to name lookup and how
9286	/// far name lookup should work. These criteria are important both
9287	/// for capturing language semantics (certain lookups will ignore
9288	/// certain names, for example) and for performance, since name
9289	/// lookup is often a bottleneck in the compilation of C++. Name
9290	/// lookup criteria is specified via the LookupCriteria enumeration.
9291	///
9292	/// The results of name lookup can vary based on the kind of name
9293	/// lookup performed, the current language, and the translation
9294	/// unit. In C, for example, name lookup will either return nothing
9295	/// (no entity found) or a single declaration. In C++, name lookup
9296	/// can additionally refer to a set of overloaded functions or
9297	/// result in an ambiguity. All of the possible results of name
9298	/// lookup are captured by the LookupResult class, which provides
9299	/// the ability to distinguish among them.
9300	///
9301	/// Implementations are in SemaLookup.cpp
9302	///@{
9303
9304	public:
9305	/// Tracks whether we are in a context where typo correction is
9306	/// disabled.
9307	bool DisableTypoCorrection;
9308
9309	/// The number of typos corrected by CorrectTypo.
9310	unsigned TyposCorrected;
9311
9312	typedef llvm::SmallSet<SourceLocation, `2`> SrcLocSet;
9313	typedef llvm::DenseMap<IdentifierInfo *, SrcLocSet> IdentifierSourceLocations;
9314
9315	/// A cache containing identifiers for which typo correction failed and
9316	/// their locations, so that repeated attempts to correct an identifier in a
9317	/// given location are ignored if typo correction already failed for it.
9318	IdentifierSourceLocations TypoCorrectionFailures;
9319
9320	/// SpecialMemberOverloadResult - The overloading result for a special member
9321	/// function.
9322	///
9323	/// This is basically a wrapper around PointerIntPair. The lowest bits of the
9324	/// integer are used to determine whether overload resolution succeeded.
9325	class SpecialMemberOverloadResult {
9326	public:
9327	enum Kind { NoMemberOrDeleted, Ambiguous, Success };
9328
9329	private:
9330	llvm::PointerIntPair<CXXMethodDecl *, `2`> Pair;
9331
9332	public:
9333	SpecialMemberOverloadResult() {}
9334	SpecialMemberOverloadResult(CXXMethodDecl *MD)
9335	: Pair (MD, MD->isDeleted() ? NoMemberOrDeleted : Success) {}
9336
9337	CXXMethodDecl getMethod() const* { return Pair.getPointer(); }
9338	void setMethod(CXXMethodDecl *MD) { Pair.setPointer(MD); }
9339
9340	Kind getKind() const { return static_cast<Kind>(Pair.getInt()); }
9341	void setKind(Kind K) { Pair.setInt(K); }
9342	};
9343
9344	class SpecialMemberOverloadResultEntry : public llvm::FastFoldingSetNode,
9345	public SpecialMemberOverloadResult {
9346	public:
9347	SpecialMemberOverloadResultEntry(const llvm::FoldingSetNodeID &ID)
9348	: FastFoldingSetNode (ID) {}
9349	};
9350
9351	/// A cache of special member function overload resolution results
9352	/// for C++ records.
9353	llvm::FoldingSet<SpecialMemberOverloadResultEntry> SpecialMemberCache;
9354
9355	enum class AcceptableKind { Visible, Reachable };
9356
9357	// Members have to be NamespaceDecl or TranslationUnitDecl.
9358	// TODO: make this is a typesafe union.
9359	typedef llvm::SmallSetVector<DeclContext *, `16`> AssociatedNamespaceSet;
9360	typedef llvm::SmallSetVector<CXXRecordDecl *, `16`> AssociatedClassSet;
9361
9362	/// Describes the kind of name lookup to perform.
9363	enum LookupNameKind {
9364	/// Ordinary name lookup, which finds ordinary names (functions,
9365	/// variables, typedefs, etc.) in C and most kinds of names
9366	/// (functions, variables, members, types, etc.) in C++.
9367	LookupOrdinaryName = `0`,
9368	/// Tag name lookup, which finds the names of enums, classes,
9369	/// structs, and unions.
9370	LookupTagName,
9371	/// Label name lookup.
9372	LookupLabel,
9373	/// Member name lookup, which finds the names of
9374	/// class/struct/union members.
9375	LookupMemberName,
9376	/// Look up of an operator name (e.g., operator+) for use with
9377	/// operator overloading. This lookup is similar to ordinary name
9378	/// lookup, but will ignore any declarations that are class members.
9379	LookupOperatorName,
9380	/// Look up a name following ~ in a destructor name. This is an ordinary
9381	/// lookup, but prefers tags to typedefs.
9382	LookupDestructorName,
9383	/// Look up of a name that precedes the '::' scope resolution
9384	/// operator in C++. This lookup completely ignores operator, object,
9385	/// function, and enumerator names (C++ [basic.lookup.qual]p1).
9386	LookupNestedNameSpecifierName,
9387	/// Look up a namespace name within a C++ using directive or
9388	/// namespace alias definition, ignoring non-namespace names (C++
9389	/// [basic.lookup.udir]p1).
9390	LookupNamespaceName,
9391	/// Look up all declarations in a scope with the given name,
9392	/// including resolved using declarations. This is appropriate
9393	/// for checking redeclarations for a using declaration.
9394	LookupUsingDeclName,
9395	/// Look up an ordinary name that is going to be redeclared as a
9396	/// name with linkage. This lookup ignores any declarations that
9397	/// are outside of the current scope unless they have linkage. See
9398	/// C99 6.2.2p4-5 and C++ [basic.link]p6.
9399	LookupRedeclarationWithLinkage,
9400	/// Look up a friend of a local class. This lookup does not look
9401	/// outside the innermost non-class scope. See C++11 [class.friend]p11.
9402	LookupLocalFriendName,
9403	/// Look up the name of an Objective-C protocol.
9404	LookupObjCProtocolName,
9405	/// Look up implicit 'self' parameter of an objective-c method.
9406	LookupObjCImplicitSelfParam,
9407	/// Look up the name of an OpenMP user-defined reduction operation.
9408	LookupOMPReductionName,
9409	/// Look up the name of an OpenMP user-defined mapper.
9410	LookupOMPMapperName,
9411	/// Look up any declaration with any name.
9412	LookupAnyName
9413	};
9414
9415	/// The possible outcomes of name lookup for a literal operator.
9416	enum LiteralOperatorLookupResult {
9417	/// The lookup resulted in an error.
9418	LOLR_Error,
9419	/// The lookup found no match but no diagnostic was issued.
9420	LOLR_ErrorNoDiagnostic,
9421	/// The lookup found a single 'cooked' literal operator, which
9422	/// expects a normal literal to be built and passed to it.
9423	LOLR_Cooked,
9424	/// The lookup found a single 'raw' literal operator, which expects
9425	/// a string literal containing the spelling of the literal token.
9426	LOLR_Raw,
9427	/// The lookup found an overload set of literal operator templates,
9428	/// which expect the characters of the spelling of the literal token to be
9429	/// passed as a non-type template argument pack.
9430	LOLR_Template,
9431	/// The lookup found an overload set of literal operator templates,
9432	/// which expect the character type and characters of the spelling of the
9433	/// string literal token to be passed as template arguments.
9434	LOLR_StringTemplatePack,
9435	};
9436
9437	SpecialMemberOverloadResult
9438	LookupSpecialMember(CXXRecordDecl D, CXXSpecialMemberKind SM, bool* ConstArg,
9439	bool VolatileArg, bool RValueThis, bool ConstThis,
9440	bool VolatileThis);
9441
9442	RedeclarationKind forRedeclarationInCurContext() const;
9443
9444	/// Look up a name, looking for a single declaration. Return
9445	/// null if the results were absent, ambiguous, or overloaded.
9446	///
9447	/// It is preferable to use the elaborated form and explicitly handle
9448	/// ambiguity and overloaded.
9449	NamedDecl *LookupSingleName(
9450	Scope *S, DeclarationName Name, SourceLocation Loc,
9451	LookupNameKind NameKind,
9452	RedeclarationKind Redecl = RedeclarationKind::NotForRedeclaration);
9453
9454	/// Lookup a builtin function, when name lookup would otherwise
9455	/// fail.
9456	bool LookupBuiltin(LookupResult &R);
9457	void LookupNecessaryTypesForBuiltin(Scope S, unsigned* ID);
9458
9459	/// Perform unqualified name lookup starting from a given
9460	/// scope.
9461	///
9462	/// Unqualified name lookup (C++ [basic.lookup.unqual], C99 6.2.1) is
9463	/// used to find names within the current scope. For example, 'x' in
9464	/// @code
9465	/// int x;
9466	/// int f() {
9467	/// return x; // unqualified name look finds 'x' in the global scope
9468	/// }
9469	/// @endcode
9470	///
9471	/// Different lookup criteria can find different names. For example, a
9472	/// particular scope can have both a struct and a function of the same
9473	/// name, and each can be found by certain lookup criteria. For more
9474	/// information about lookup criteria, see the documentation for the
9475	/// class LookupCriteria.
9476	///
9477	/// @param S The scope from which unqualified name lookup will
9478	/// begin. If the lookup criteria permits, name lookup may also search
9479	/// in the parent scopes.
9480	///
9481	/// @param [in,out] R Specifies the lookup to perform (e.g., the name to
9482	/// look up and the lookup kind), and is updated with the results of lookup
9483	/// including zero or more declarations and possibly additional information
9484	/// used to diagnose ambiguities.
9485	///
9486	/// @returns \c true if lookup succeeded and false otherwise.
9487	bool LookupName(LookupResult &R, Scope S, bool* AllowBuiltinCreation = false,
9488	bool ForceNoCPlusPlus = false);
9489
9490	/// Perform qualified name lookup into a given context.
9491	///
9492	/// Qualified name lookup (C++ [basic.lookup.qual]) is used to find
9493	/// names when the context of those names is explicit specified, e.g.,
9494	/// "std::vector" or "x->member", or as part of unqualified name lookup.
9495	///
9496	/// Different lookup criteria can find different names. For example, a
9497	/// particular scope can have both a struct and a function of the same
9498	/// name, and each can be found by certain lookup criteria. For more
9499	/// information about lookup criteria, see the documentation for the
9500	/// class LookupCriteria.
9501	///
9502	/// \param R captures both the lookup criteria and any lookup results found.
9503	///
9504	/// \param LookupCtx The context in which qualified name lookup will
9505	/// search. If the lookup criteria permits, name lookup may also search
9506	/// in the parent contexts or (for C++ classes) base classes.
9507	///
9508	/// \param InUnqualifiedLookup true if this is qualified name lookup that
9509	/// occurs as part of unqualified name lookup.
9510	///
9511	/// \returns true if lookup succeeded, false if it failed.
9512	bool LookupQualifiedName(LookupResult &R, DeclContext *LookupCtx,
9513	bool InUnqualifiedLookup = false);
9514
9515	/// Performs qualified name lookup or special type of lookup for
9516	/// "__super::" scope specifier.
9517	///
9518	/// This routine is a convenience overload meant to be called from contexts
9519	/// that need to perform a qualified name lookup with an optional C++ scope
9520	/// specifier that might require special kind of lookup.
9521	///
9522	/// \param R captures both the lookup criteria and any lookup results found.
9523	///
9524	/// \param LookupCtx The context in which qualified name lookup will
9525	/// search.
9526	///
9527	/// \param SS An optional C++ scope-specifier.
9528	///
9529	/// \returns true if lookup succeeded, false if it failed.
9530	bool LookupQualifiedName(LookupResult &R, DeclContext *LookupCtx,
9531	CXXScopeSpec &SS);
9532
9533	/// Performs name lookup for a name that was parsed in the
9534	/// source code, and may contain a C++ scope specifier.
9535	///
9536	/// This routine is a convenience routine meant to be called from
9537	/// contexts that receive a name and an optional C++ scope specifier
9538	/// (e.g., "N::M::x"). It will then perform either qualified or
9539	/// unqualified name lookup (with LookupQualifiedName or LookupName,
9540	/// respectively) on the given name and return those results. It will
9541	/// perform a special type of lookup for "__super::" scope specifier.
9542	///
9543	/// @param S The scope from which unqualified name lookup will
9544	/// begin.
9545	///
9546	/// @param SS An optional C++ scope-specifier, e.g., "::N::M".
9547	///
9548	/// @param EnteringContext Indicates whether we are going to enter the
9549	/// context of the scope-specifier SS (if present).
9550	///
9551	/// @returns True if any decls were found (but possibly ambiguous)
9552	bool LookupParsedName(LookupResult &R, Scope S, CXXScopeSpec SS,
9553	QualType ObjectType, bool AllowBuiltinCreation = false,
9554	bool EnteringContext = false);
9555
9556	/// Perform qualified name lookup into all base classes of the given
9557	/// class.
9558	///
9559	/// \param R captures both the lookup criteria and any lookup results found.
9560	///
9561	/// \param Class The context in which qualified name lookup will
9562	/// search. Name lookup will search in all base classes merging the results.
9563	///
9564	/// @returns True if any decls were found (but possibly ambiguous)
9565	bool LookupInSuper(LookupResult &R, CXXRecordDecl *Class);
9566
9567	void LookupOverloadedOperatorName(OverloadedOperatorKind Op, Scope *S,
9568	UnresolvedSetImpl &Functions);
9569
9570	/// LookupOrCreateLabel - Do a name lookup of a label with the specified name.
9571	/// If GnuLabelLoc is a valid source location, then this is a definition
9572	/// of an __label__ label name, otherwise it is a normal label definition
9573	/// or use. If IsLabelStmt is true, then this is the label of a
9574	/// labeled-statement.
9575	LabelDecl LookupOrCreateLabel(IdentifierInfo II, SourceLocation IdentLoc,
9576	SourceLocation GnuLabelLoc = SourceLocation (),
9577	bool IsLabelStmt = false);
9578
9579	/// Perform a name lookup for a label with the specified name; this does not
9580	/// create a new label if the lookup fails.
9581	LabelDecl LookupExistingLabel(IdentifierInfo II, SourceLocation IdentLoc);
9582
9583	/// Look up the constructors for the given class.
9584	DeclContextLookupResult LookupConstructors(CXXRecordDecl *Class);
9585
9586	/// Look up the default constructor for the given class.
9587	CXXConstructorDecl LookupDefaultConstructor(CXXRecordDecl Class);
9588
9589	/// Look up the copying constructor for the given class.
9590	CXXConstructorDecl LookupCopyingConstructor(CXXRecordDecl Class,
9591	unsigned Quals);
9592
9593	/// Look up the copying assignment operator for the given class.
9594	CXXMethodDecl LookupCopyingAssignment(CXXRecordDecl Class, unsigned Quals,
9595	bool RValueThis, unsigned ThisQuals);
9596
9597	/// Look up the moving constructor for the given class.
9598	CXXConstructorDecl LookupMovingConstructor(CXXRecordDecl Class,
9599	unsigned Quals);
9600
9601	/// Look up the moving assignment operator for the given class.
9602	CXXMethodDecl LookupMovingAssignment(CXXRecordDecl Class, unsigned Quals,
9603	bool RValueThis, unsigned ThisQuals);
9604
9605	/// Look for the destructor of the given class.
9606	///
9607	/// During semantic analysis, this routine should be used in lieu of
9608	/// CXXRecordDecl::getDestructor().
9609	///
9610	/// \returns The destructor for this class.
9611	CXXDestructorDecl LookupDestructor(CXXRecordDecl Class);
9612
9613	/// Force the declaration of any implicitly-declared members of this
9614	/// class.
9615	void ForceDeclarationOfImplicitMembers(CXXRecordDecl *Class);
9616
9617	/// Make a merged definition of an existing hidden definition \p ND
9618	/// visible at the specified location.
9619	void makeMergedDefinitionVisible(NamedDecl *ND);
9620
9621	/// Check ODR hashes for C/ObjC when merging types from modules.
9622	/// Differently from C++, actually parse the body and reject in case
9623	/// of a mismatch.
9624	template <typename T,
9625	typename = std::enable_if_t<std::is_base_of<NamedDecl, T>::value>>
9626	bool ActOnDuplicateODRHashDefinition(T Duplicate, T Previous) {
9627	if (Duplicate->getODRHash() != Previous->getODRHash())
9628	return false;
9629
9630	// Make the previous decl visible.
9631	makeMergedDefinitionVisible(ND: Previous);
9632	return true;
9633	}
9634
9635	/// Get the set of additional modules that should be checked during
9636	/// name lookup. A module and its imports become visible when instanting a
9637	/// template defined within it.
9638	llvm::DenseSet<Module *> &getLookupModules();
9639
9640	bool hasVisibleMergedDefinition(const NamedDecl *Def);
9641	bool hasMergedDefinitionInCurrentModule(const NamedDecl *Def);
9642
9643	/// Determine if the template parameter \p D has a visible default argument.
9644	bool
9645	hasVisibleDefaultArgument(const NamedDecl *D,
9646	llvm::SmallVectorImpl<Module > Modules = nullptr);
9647	/// Determine if the template parameter \p D has a reachable default argument.
9648	bool hasReachableDefaultArgument(
9649	const NamedDecl D, llvm::SmallVectorImpl<Module > Modules = nullptr*);
9650	/// Determine if the template parameter \p D has a reachable default argument.
9651	bool hasAcceptableDefaultArgument(const NamedDecl *D,
9652	llvm::SmallVectorImpl<Module > Modules,
9653	Sema::AcceptableKind Kind);
9654
9655	/// Determine if there is a visible declaration of \p D that is an explicit
9656	/// specialization declaration for a specialization of a template. (For a
9657	/// member specialization, use hasVisibleMemberSpecialization.)
9658	bool hasVisibleExplicitSpecialization(
9659	const NamedDecl D, llvm::SmallVectorImpl<Module > Modules = nullptr*);
9660	/// Determine if there is a reachable declaration of \p D that is an explicit
9661	/// specialization declaration for a specialization of a template. (For a
9662	/// member specialization, use hasReachableMemberSpecialization.)
9663	bool hasReachableExplicitSpecialization(
9664	const NamedDecl D, llvm::SmallVectorImpl<Module > Modules = nullptr*);
9665
9666	/// Determine if there is a visible declaration of \p D that is a member
9667	/// specialization declaration (as opposed to an instantiated declaration).
9668	bool hasVisibleMemberSpecialization(
9669	const NamedDecl D, llvm::SmallVectorImpl<Module > Modules = nullptr*);
9670	/// Determine if there is a reachable declaration of \p D that is a member
9671	/// specialization declaration (as opposed to an instantiated declaration).
9672	bool hasReachableMemberSpecialization(
9673	const NamedDecl D, llvm::SmallVectorImpl<Module > Modules = nullptr*);
9674
9675	bool isModuleVisible(const Module M, bool* ModulePrivate = false);
9676
9677	/// Determine whether any declaration of an entity is visible.
9678	bool
9679	hasVisibleDeclaration(const NamedDecl *D,
9680	llvm::SmallVectorImpl<Module > Modules = nullptr) {
9681	return isVisible(D) \|\| hasVisibleDeclarationSlow(D, Modules);
9682	}
9683
9684	bool hasVisibleDeclarationSlow(const NamedDecl *D,
9685	llvm::SmallVectorImpl<Module > Modules);
9686	/// Determine whether any declaration of an entity is reachable.
9687	bool
9688	hasReachableDeclaration(const NamedDecl *D,
9689	llvm::SmallVectorImpl<Module > Modules = nullptr) {
9690	return isReachable(D) \|\| hasReachableDeclarationSlow(D, Modules);
9691	}
9692	bool hasReachableDeclarationSlow(
9693	const NamedDecl D, llvm::SmallVectorImpl<Module > Modules = nullptr*);
9694
9695	void diagnoseTypo(const TypoCorrection &Correction,
9696	const PartialDiagnostic &TypoDiag,
9697	bool ErrorRecovery = true);
9698
9699	/// Diagnose a successfully-corrected typo. Separated from the correction
9700	/// itself to allow external validation of the result, etc.
9701	///
9702	/// \param Correction The result of performing typo correction.
9703	/// \param TypoDiag The diagnostic to produce. This will have the corrected
9704	/// string added to it (and usually also a fixit).
9705	/// \param PrevNote A note to use when indicating the location of the entity
9706	/// to which we are correcting. Will have the correction string added
9707	/// to it.
9708	/// \param ErrorRecovery If \c true (the default), the caller is going to
9709	/// recover from the typo as if the corrected string had been typed.
9710	/// In this case, \c PDiag must be an error, and we will attach a fixit
9711	/// to it.
9712	void diagnoseTypo(const TypoCorrection &Correction,
9713	const PartialDiagnostic &TypoDiag,
9714	const PartialDiagnostic &PrevNote,
9715	bool ErrorRecovery = true);
9716
9717	/// Find the associated classes and namespaces for
9718	/// argument-dependent lookup for a call with the given set of
9719	/// arguments.
9720	///
9721	/// This routine computes the sets of associated classes and associated
9722	/// namespaces searched by argument-dependent lookup
9723	/// (C++ [basic.lookup.argdep]) for a given set of arguments.
9724	void FindAssociatedClassesAndNamespaces(
9725	SourceLocation InstantiationLoc, ArrayRef<Expr *> Args,
9726	AssociatedNamespaceSet &AssociatedNamespaces,
9727	AssociatedClassSet &AssociatedClasses);
9728
9729	/// Produce a diagnostic describing the ambiguity that resulted
9730	/// from name lookup.
9731	///
9732	/// \param Result The result of the ambiguous lookup to be diagnosed.
9733	void DiagnoseAmbiguousLookup(LookupResult &Result);
9734
9735	/// LookupLiteralOperator - Determine which literal operator should be used
9736	/// for a user-defined literal, per C++11 [lex.ext].
9737	///
9738	/// Normal overload resolution is not used to select which literal operator to
9739	/// call for a user-defined literal. Look up the provided literal operator
9740	/// name, and filter the results to the appropriate set for the given argument
9741	/// types.
9742	LiteralOperatorLookupResult
9743	LookupLiteralOperator(Scope *S, LookupResult &R, ArrayRef<QualType> ArgTys,
9744	bool AllowRaw, bool AllowTemplate,
9745	bool AllowStringTemplate, bool DiagnoseMissing,
9746	StringLiteral StringLit = nullptr*);
9747
9748	void ArgumentDependentLookup(DeclarationName Name, SourceLocation Loc,
9749	ArrayRef<Expr *> Args, ADLResult &Functions);
9750
9751	void LookupVisibleDecls(Scope *S, LookupNameKind Kind,
9752	VisibleDeclConsumer &Consumer,
9753	bool IncludeGlobalScope = true,
9754	bool LoadExternal = true);
9755	void LookupVisibleDecls(DeclContext *Ctx, LookupNameKind Kind,
9756	VisibleDeclConsumer &Consumer,
9757	bool IncludeGlobalScope = true,
9758	bool IncludeDependentBases = false,
9759	bool LoadExternal = true);
9760
9761	/// Try to "correct" a typo in the source code by finding
9762	/// visible declarations whose names are similar to the name that was
9763	/// present in the source code.
9764	///
9765	/// \param TypoName the \c DeclarationNameInfo structure that contains
9766	/// the name that was present in the source code along with its location.
9767	///
9768	/// \param LookupKind the name-lookup criteria used to search for the name.
9769	///
9770	/// \param S the scope in which name lookup occurs.
9771	///
9772	/// \param SS the nested-name-specifier that precedes the name we're
9773	/// looking for, if present.
9774	///
9775	/// \param CCC A CorrectionCandidateCallback object that provides further
9776	/// validation of typo correction candidates. It also provides flags for
9777	/// determining the set of keywords permitted.
9778	///
9779	/// \param MemberContext if non-NULL, the context in which to look for
9780	/// a member access expression.
9781	///
9782	/// \param EnteringContext whether we're entering the context described by
9783	/// the nested-name-specifier SS.
9784	///
9785	/// \param OPT when non-NULL, the search for visible declarations will
9786	/// also walk the protocols in the qualified interfaces of \p OPT.
9787	///
9788	/// \returns a \c TypoCorrection containing the corrected name if the typo
9789	/// along with information such as the \c NamedDecl where the corrected name
9790	/// was declared, and any additional \c NestedNameSpecifier needed to access
9791	/// it (C++ only). The \c TypoCorrection is empty if there is no correction.
9792	TypoCorrection CorrectTypo(const DeclarationNameInfo &Typo,
9793	Sema::LookupNameKind LookupKind, Scope *S,
9794	CXXScopeSpec *SS, CorrectionCandidateCallback &CCC,
9795	CorrectTypoKind Mode,
9796	DeclContext MemberContext = nullptr*,
9797	bool EnteringContext = false,
9798	const ObjCObjectPointerType OPT = nullptr*,
9799	bool RecordFailure = true);
9800
9801	/// Kinds of missing import. Note, the values of these enumerators correspond
9802	/// to %select values in diagnostics.
9803	enum class MissingImportKind {
9804	Declaration,
9805	Definition,
9806	DefaultArgument,
9807	ExplicitSpecialization,
9808	PartialSpecialization
9809	};
9810
9811	/// Diagnose that the specified declaration needs to be visible but
9812	/// isn't, and suggest a module import that would resolve the problem.
9813	void diagnoseMissingImport(SourceLocation Loc, const NamedDecl *Decl,
9814	MissingImportKind MIK, bool Recover = true);
9815	void diagnoseMissingImport(SourceLocation Loc, const NamedDecl *Decl,
9816	SourceLocation DeclLoc, ArrayRef<Module *> Modules,
9817	MissingImportKind MIK, bool Recover);
9818
9819	/// Called on #pragma clang __debug dump II
9820	void ActOnPragmaDump(Scope S, SourceLocation Loc, IdentifierInfo II);
9821
9822	/// Called on #pragma clang __debug dump E
9823	void ActOnPragmaDump(Expr *E);
9824
9825	private:
9826	// The set of known/encountered (unique, canonicalized) NamespaceDecls.
9827	//
9828	// The boolean value will be true to indicate that the namespace was loaded
9829	// from an AST/PCH file, or false otherwise.
9830	llvm::MapVector<NamespaceDecl , bool*> KnownNamespaces;
9831
9832	/// Whether we have already loaded known namespaces from an extenal
9833	/// source.
9834	bool LoadedExternalKnownNamespaces;
9835
9836	bool CppLookupName(LookupResult &R, Scope *S);
9837
9838	/// Determine if we could use all the declarations in the module.
9839	bool isUsableModule(const Module *M);
9840
9841	/// Helper for CorrectTypo used to create and populate a new
9842	/// TypoCorrectionConsumer. Returns nullptr if typo correction should be
9843	/// skipped entirely.
9844	std::unique_ptr<TypoCorrectionConsumer> makeTypoCorrectionConsumer(
9845	const DeclarationNameInfo &Typo, Sema::LookupNameKind LookupKind,
9846	Scope S, CXXScopeSpec SS, CorrectionCandidateCallback &CCC,
9847	DeclContext MemberContext, bool* EnteringContext,
9848	const ObjCObjectPointerType OPT, bool* ErrorRecovery);
9849
9850	/// Cache for module units which is usable for current module.
9851	llvm::DenseSet<const Module *> UsableModuleUnitsCache;
9852
9853	/// Record the typo correction failure and return an empty correction.
9854	TypoCorrection FailedCorrection(IdentifierInfo *Typo, SourceLocation TypoLoc,
9855	bool RecordFailure = true) {
9856	if (RecordFailure)
9857	TypoCorrectionFailures [Typo].insert(V: TypoLoc);
9858	return TypoCorrection ();
9859	}
9860
9861	bool isAcceptableSlow(const NamedDecl *D, AcceptableKind Kind);
9862
9863	/// Determine whether two declarations should be linked together, given that
9864	/// the old declaration might not be visible and the new declaration might
9865	/// not have external linkage.
9866	bool shouldLinkPossiblyHiddenDecl(const NamedDecl *Old,
9867	const NamedDecl *New) {
9868	if (isVisible(D: Old))
9869	return true;
9870	// See comment in below overload for why it's safe to compute the linkage
9871	// of the new declaration here.
9872	if (New->isExternallyDeclarable()) {
9873	assert(Old->isExternallyDeclarable() &&
9874	"should not have found a non-externally-declarable previous decl");
9875	return true;
9876	}
9877	return false;
9878	}
9879	bool shouldLinkPossiblyHiddenDecl(LookupResult &Old, const NamedDecl *New);
9880
9881	///@}
9882
9883	//
9884	//
9885	// -------------------------------------------------------------------------
9886	//
9887	//
9888
9889	/// \name Modules
9890	/// Implementations are in SemaModule.cpp
9891	///@{
9892
9893	public:
9894	/// Get the module unit whose scope we are currently within.
9895	Module getCurrentModule() const* {
9896	return ModuleScopes.empty() ? nullptr : ModuleScopes.back().Module;
9897	}
9898
9899	/// Is the module scope we are an implementation unit?
9900	bool currentModuleIsImplementation() const {
9901	if (ModuleScopes.empty())
9902	return false;
9903	const Module *M = ModuleScopes.back().Module;
9904	return M->isModuleImplementation() \|\| M->isModulePartitionImplementation();
9905	}
9906
9907	// When loading a non-modular PCH files, this is used to restore module
9908	// visibility.
9909	void makeModuleVisible(Module *Mod, SourceLocation ImportLoc) {
9910	VisibleModules.setVisible(M: Mod, Loc: ImportLoc);
9911	}
9912
9913	enum class ModuleDeclKind {
9914	Interface, ///< 'export module X;'
9915	Implementation, ///< 'module X;'
9916	PartitionInterface, ///< 'export module X:Y;'
9917	PartitionImplementation, ///< 'module X:Y;'
9918	};
9919
9920	/// An enumeration to represent the transition of states in parsing module
9921	/// fragments and imports. If we are not parsing a C++20 TU, or we find
9922	/// an error in state transition, the state is set to NotACXX20Module.
9923	enum class ModuleImportState {
9924	FirstDecl, ///< Parsing the first decl in a TU.
9925	GlobalFragment, ///< after 'module;' but before 'module X;'
9926	ImportAllowed, ///< after 'module X;' but before any non-import decl.
9927	ImportFinished, ///< after any non-import decl.
9928	PrivateFragmentImportAllowed, ///< after 'module :private;' but before any
9929	///< non-import decl.
9930	PrivateFragmentImportFinished, ///< after 'module :private;' but a
9931	///< non-import decl has already been seen.
9932	NotACXX20Module ///< Not a C++20 TU, or an invalid state was found.
9933	};
9934
9935	/// The parser has processed a module-declaration that begins the definition
9936	/// of a module interface or implementation.
9937	DeclGroupPtrTy ActOnModuleDecl(SourceLocation StartLoc,
9938	SourceLocation ModuleLoc, ModuleDeclKind MDK,
9939	ModuleIdPath Path, ModuleIdPath Partition,
9940	ModuleImportState &ImportState,
9941	bool SeenNoTrivialPPDirective);
9942
9943	/// The parser has processed a global-module-fragment declaration that begins
9944	/// the definition of the global module fragment of the current module unit.
9945	/// \param ModuleLoc The location of the 'module' keyword.
9946	DeclGroupPtrTy ActOnGlobalModuleFragmentDecl(SourceLocation ModuleLoc);
9947
9948	/// The parser has processed a private-module-fragment declaration that begins
9949	/// the definition of the private module fragment of the current module unit.
9950	/// \param ModuleLoc The location of the 'module' keyword.
9951	/// \param PrivateLoc The location of the 'private' keyword.
9952	DeclGroupPtrTy ActOnPrivateModuleFragmentDecl(SourceLocation ModuleLoc,
9953	SourceLocation PrivateLoc);
9954
9955	/// The parser has processed a module import declaration.
9956	///
9957	/// \param StartLoc The location of the first token in the declaration. This
9958	/// could be the location of an '@', 'export', or 'import'.
9959	/// \param ExportLoc The location of the 'export' keyword, if any.
9960	/// \param ImportLoc The location of the 'import' keyword.
9961	/// \param Path The module toplevel name as an access path.
9962	/// \param IsPartition If the name is for a partition.
9963	DeclResult ActOnModuleImport(SourceLocation StartLoc,
9964	SourceLocation ExportLoc,
9965	SourceLocation ImportLoc, ModuleIdPath Path,
9966	bool IsPartition = false);
9967	DeclResult ActOnModuleImport(SourceLocation StartLoc,
9968	SourceLocation ExportLoc,
9969	SourceLocation ImportLoc, Module *M,
9970	ModuleIdPath Path = {});
9971
9972	/// The parser has processed a module import translated from a
9973	/// #include or similar preprocessing directive.
9974	void ActOnAnnotModuleInclude(SourceLocation DirectiveLoc, Module *Mod);
9975	void BuildModuleInclude(SourceLocation DirectiveLoc, Module *Mod);
9976
9977	/// The parsed has entered a submodule.
9978	void ActOnAnnotModuleBegin(SourceLocation DirectiveLoc, Module *Mod);
9979	/// The parser has left a submodule.
9980	void ActOnAnnotModuleEnd(SourceLocation DirectiveLoc, Module *Mod);
9981
9982	/// Create an implicit import of the given module at the given
9983	/// source location, for error recovery, if possible.
9984	///
9985	/// This routine is typically used when an entity found by name lookup
9986	/// is actually hidden within a module that we know about but the user
9987	/// has forgotten to import.
9988	void createImplicitModuleImportForErrorRecovery(SourceLocation Loc,
9989	Module *Mod);
9990
9991	/// We have parsed the start of an export declaration, including the '{'
9992	/// (if present).
9993	Decl ActOnStartExportDecl(Scope S, SourceLocation ExportLoc,
9994	SourceLocation LBraceLoc);
9995
9996	/// Complete the definition of an export declaration.
9997	Decl ActOnFinishExportDecl(Scope S, Decl *ExportDecl,
9998	SourceLocation RBraceLoc);
9999
10000	private:
10001	/// The parser has begun a translation unit to be compiled as a C++20
10002	/// Header Unit, helper for ActOnStartOfTranslationUnit() only.
10003	void HandleStartOfHeaderUnit();
10004
10005	struct ModuleScope {
10006	SourceLocation BeginLoc;
10007	clang::Module Module = nullptr*;
10008	VisibleModuleSet OuterVisibleModules;
10009	};
10010	/// The modules we're currently parsing.
10011	llvm::SmallVector<ModuleScope, `16`> ModuleScopes;
10012
10013	/// For an interface unit, this is the implicitly imported interface unit.
10014	clang::Module ThePrimaryInterface = nullptr*;
10015
10016	/// The explicit global module fragment of the current translation unit.
10017	/// The explicit Global Module Fragment, as specified in C++
10018	/// [module.global.frag].
10019	clang::Module TheGlobalModuleFragment = nullptr*;
10020
10021	/// The implicit global module fragments of the current translation unit.
10022	///
10023	/// The contents in the implicit global module fragment can't be discarded.
10024	clang::Module TheImplicitGlobalModuleFragment = nullptr*;
10025
10026	/// Namespace definitions that we will export when they finish.
10027	llvm::SmallPtrSet<const NamespaceDecl *, `8`> DeferredExportedNamespaces;
10028
10029	/// In a C++ standard module, inline declarations require a definition to be
10030	/// present at the end of a definition domain. This set holds the decls to
10031	/// be checked at the end of the TU.
10032	llvm::SmallPtrSet<const FunctionDecl *, `8`> PendingInlineFuncDecls;
10033
10034	/// Helper function to judge if we are in module purview.
10035	/// Return false if we are not in a module.
10036	bool isCurrentModulePurview() const;
10037
10038	/// Enter the scope of the explicit global module fragment.
10039	Module *PushGlobalModuleFragment(SourceLocation BeginLoc);
10040	/// Leave the scope of the explicit global module fragment.
10041	void PopGlobalModuleFragment();
10042
10043	/// Enter the scope of an implicit global module fragment.
10044	Module *PushImplicitGlobalModuleFragment(SourceLocation BeginLoc);
10045	/// Leave the scope of an implicit global module fragment.
10046	void PopImplicitGlobalModuleFragment();
10047
10048	VisibleModuleSet VisibleModules;
10049
10050	/// Whether we had imported any named modules.
10051	bool HadImportedNamedModules = false;
10052	/// The set of instantiations we need to check if they references TU-local
10053	/// entity from TUs. This only makes sense if we imported any named modules.
10054	llvm::SmallVector<std::pair<FunctionDecl *, SourceLocation>>
10055	PendingCheckReferenceForTULocal;
10056	/// Implement [basic.link]p18, which requires that we can't use TU-local
10057	/// entities from other TUs (ignoring header units).
10058	void checkReferenceToTULocalFromOtherTU(FunctionDecl *FD,
10059	SourceLocation PointOfInstantiation);
10060	/// Implement [basic.link]p17, which diagnose for non TU local exposure in
10061	/// module interface or module partition.
10062	void checkExposure(const TranslationUnitDecl *TU);
10063
10064	///@}
10065
10066	//
10067	//
10068	// -------------------------------------------------------------------------
10069	//
10070	//
10071
10072	/// \name C++ Overloading
10073	/// Implementations are in SemaOverload.cpp
10074	///@{
10075
10076	public:
10077	/// Whether deferrable diagnostics should be deferred.
10078	bool DeferDiags = false;
10079
10080	/// RAII class to control scope of DeferDiags.
10081	class DeferDiagsRAII {
10082	Sema &S;
10083	bool SavedDeferDiags = false;
10084
10085	public:
10086	DeferDiagsRAII(Sema &S, bool DeferDiags)
10087	: S(S), SavedDeferDiags(S.DeferDiags) {
10088	S.DeferDiags = SavedDeferDiags \|\| DeferDiags;
10089	}
10090	~DeferDiagsRAII() { S.DeferDiags = SavedDeferDiags; }
10091	DeferDiagsRAII(const DeferDiagsRAII &) = delete;
10092	DeferDiagsRAII &operator=(const DeferDiagsRAII &) = delete;
10093	};
10094
10095	/// Flag indicating if Sema is building a recovery call expression.
10096	///
10097	/// This flag is used to avoid building recovery call expressions
10098	/// if Sema is already doing so, which would cause infinite recursions.
10099	bool IsBuildingRecoveryCallExpr;
10100
10101	/// Determine whether the given New declaration is an overload of the
10102	/// declarations in Old. This routine returns OverloadKind::Match or
10103	/// OverloadKind::NonFunction if New and Old cannot be overloaded, e.g., if
10104	/// New has the same signature as some function in Old (C++ 1.3.10) or if the
10105	/// Old declarations aren't functions (or function templates) at all. When it
10106	/// does return OverloadKind::Match or OverloadKind::NonFunction, MatchedDecl
10107	/// will point to the decl that New cannot be overloaded with. This decl may
10108	/// be a UsingShadowDecl on top of the underlying declaration.
10109	///
10110	/// Example: Given the following input:
10111	///
10112	/// void f(int, float); // #1
10113	/// void f(int, int); // #2
10114	/// int f(int, int); // #3
10115	///
10116	/// When we process #1, there is no previous declaration of "f", so IsOverload
10117	/// will not be used.
10118	///
10119	/// When we process #2, Old contains only the FunctionDecl for #1. By
10120	/// comparing the parameter types, we see that #1 and #2 are overloaded (since
10121	/// they have different signatures), so this routine returns
10122	/// OverloadKind::Overload; MatchedDecl is unchanged.
10123	///
10124	/// When we process #3, Old is an overload set containing #1 and #2. We
10125	/// compare the signatures of #3 to #1 (they're overloaded, so we do nothing)
10126	/// and then #3 to #2. Since the signatures of #3 and #2 are identical (return
10127	/// types of functions are not part of the signature), IsOverload returns
10128	/// OverloadKind::Match and MatchedDecl will be set to point to the
10129	/// FunctionDecl for #2.
10130	///
10131	/// 'NewIsUsingShadowDecl' indicates that 'New' is being introduced into a
10132	/// class by a using declaration. The rules for whether to hide shadow
10133	/// declarations ignore some properties which otherwise figure into a function
10134	/// template's signature.
10135	OverloadKind CheckOverload(Scope S, FunctionDecl New,
10136	const LookupResult &OldDecls, NamedDecl *&OldDecl,
10137	bool UseMemberUsingDeclRules);
10138	bool IsOverload(FunctionDecl New, FunctionDecl Old,
10139	bool UseMemberUsingDeclRules, bool ConsiderCudaAttrs = true);
10140
10141	// Checks whether MD constitutes an override the base class method BaseMD.
10142	// When checking for overrides, the object object members are ignored.
10143	bool IsOverride(FunctionDecl MD, FunctionDecl BaseMD,
10144	bool UseMemberUsingDeclRules, bool ConsiderCudaAttrs = true);
10145
10146	enum class AllowedExplicit {
10147	/// Allow no explicit functions to be used.
10148	None,
10149	/// Allow explicit conversion functions but not explicit constructors.
10150	Conversions,
10151	/// Allow both explicit conversion functions and explicit constructors.
10152	All
10153	};
10154
10155	ImplicitConversionSequence TryImplicitConversion(
10156	Expr From, QualType ToType, bool* SuppressUserConversions,
10157	AllowedExplicit AllowExplicit, bool InOverloadResolution, bool CStyle,
10158	bool AllowObjCWritebackConversion);
10159
10160	/// PerformImplicitConversion - Perform an implicit conversion of the
10161	/// expression From to the type ToType. Returns the
10162	/// converted expression. Flavor is the kind of conversion we're
10163	/// performing, used in the error message. If @p AllowExplicit,
10164	/// explicit user-defined conversions are permitted.
10165	ExprResult PerformImplicitConversion(Expr *From, QualType ToType,
10166	AssignmentAction Action,
10167	bool AllowExplicit = false);
10168
10169	/// IsIntegralPromotion - Determines whether the conversion from the
10170	/// expression From (whose potentially-adjusted type is FromType) to
10171	/// ToType is an integral promotion (C++ 4.5). If so, returns true and
10172	/// sets PromotedType to the promoted type.
10173	bool IsIntegralPromotion(Expr *From, QualType FromType, QualType ToType);
10174
10175	/// IsFloatingPointPromotion - Determines whether the conversion from
10176	/// FromType to ToType is a floating point promotion (C++ 4.6). If so,
10177	/// returns true and sets PromotedType to the promoted type.
10178	bool IsFloatingPointPromotion(QualType FromType, QualType ToType);
10179
10180	/// Determine if a conversion is a complex promotion.
10181	///
10182	/// A complex promotion is defined as a complex -> complex conversion
10183	/// where the conversion between the underlying real types is a
10184	/// floating-point or integral promotion.
10185	bool IsComplexPromotion(QualType FromType, QualType ToType);
10186
10187	/// IsOverflowBehaviorTypePromotion - Determines whether the conversion from
10188	/// FromType to ToType involves an OverflowBehaviorType FromType being
10189	/// promoted to an OverflowBehaviorType ToType which has a larger bitwidth.
10190	/// If so, returns true and sets FromType to ToType.
10191	bool IsOverflowBehaviorTypePromotion(QualType FromType, QualType ToType);
10192
10193	/// IsOverflowBehaviorTypeConversion - Determines whether the conversion from
10194	/// FromType to ToType necessarily involves both an OverflowBehaviorType and
10195	/// a non-OverflowBehaviorType. If so, returns true and sets FromType to
10196	/// ToType.
10197	bool IsOverflowBehaviorTypeConversion(QualType FromType, QualType ToType);
10198
10199	/// IsPointerConversion - Determines whether the conversion of the
10200	/// expression From, which has the (possibly adjusted) type FromType,
10201	/// can be converted to the type ToType via a pointer conversion (C++
10202	/// 4.10). If so, returns true and places the converted type (that
10203	/// might differ from ToType in its cv-qualifiers at some level) into
10204	/// ConvertedType.
10205	///
10206	/// This routine also supports conversions to and from block pointers
10207	/// and conversions with Objective-C's 'id', 'id<protocols...>', and
10208	/// pointers to interfaces. FIXME: Once we've determined the
10209	/// appropriate overloading rules for Objective-C, we may want to
10210	/// split the Objective-C checks into a different routine; however,
10211	/// GCC seems to consider all of these conversions to be pointer
10212	/// conversions, so for now they live here. IncompatibleObjC will be
10213	/// set if the conversion is an allowed Objective-C conversion that
10214	/// should result in a warning.
10215	bool IsPointerConversion(Expr *From, QualType FromType, QualType ToType,
10216	bool InOverloadResolution, QualType &ConvertedType,
10217	bool &IncompatibleObjC);
10218
10219	/// isObjCPointerConversion - Determines whether this is an
10220	/// Objective-C pointer conversion. Subroutine of IsPointerConversion,
10221	/// with the same arguments and return values.
10222	bool isObjCPointerConversion(QualType FromType, QualType ToType,
10223	QualType &ConvertedType, bool &IncompatibleObjC);
10224	bool IsBlockPointerConversion(QualType FromType, QualType ToType,
10225	QualType &ConvertedType);
10226
10227	/// FunctionParamTypesAreEqual - This routine checks two function proto types
10228	/// for equality of their parameter types. Caller has already checked that
10229	/// they have same number of parameters. If the parameters are different,
10230	/// ArgPos will have the parameter index of the first different parameter.
10231	/// If `Reversed` is true, the parameters of `NewType` will be compared in
10232	/// reverse order. That's useful if one of the functions is being used as a
10233	/// C++20 synthesized operator overload with a reversed parameter order.
10234	bool FunctionParamTypesAreEqual(ArrayRef<QualType> Old,
10235	ArrayRef<QualType> New,
10236	unsigned ArgPos = nullptr*,
10237	bool Reversed = false);
10238
10239	bool FunctionParamTypesAreEqual(const FunctionProtoType *OldType,
10240	const FunctionProtoType *NewType,
10241	unsigned ArgPos = nullptr*,
10242	bool Reversed = false);
10243
10244	bool FunctionNonObjectParamTypesAreEqual(const FunctionDecl *OldFunction,
10245	const FunctionDecl *NewFunction,
10246	unsigned ArgPos = nullptr*,
10247	bool Reversed = false);
10248
10249	/// HandleFunctionTypeMismatch - Gives diagnostic information for differeing
10250	/// function types. Catches different number of parameter, mismatch in
10251	/// parameter types, and different return types.
10252	void HandleFunctionTypeMismatch(PartialDiagnostic &PDiag, QualType FromType,
10253	QualType ToType);
10254
10255	/// CheckPointerConversion - Check the pointer conversion from the
10256	/// expression From to the type ToType. This routine checks for
10257	/// ambiguous or inaccessible derived-to-base pointer
10258	/// conversions for which IsPointerConversion has already returned
10259	/// true. It returns true and produces a diagnostic if there was an
10260	/// error, or returns false otherwise.
10261	bool CheckPointerConversion(Expr *From, QualType ToType, CastKind &Kind,
10262	CXXCastPath &BasePath, bool IgnoreBaseAccess,
10263	bool Diagnose = true);
10264
10265	/// IsMemberPointerConversion - Determines whether the conversion of the
10266	/// expression From, which has the (possibly adjusted) type FromType, can be
10267	/// converted to the type ToType via a member pointer conversion (C++ 4.11).
10268	/// If so, returns true and places the converted type (that might differ from
10269	/// ToType in its cv-qualifiers at some level) into ConvertedType.
10270	bool IsMemberPointerConversion(Expr *From, QualType FromType, QualType ToType,
10271	bool InOverloadResolution,
10272	QualType &ConvertedType);
10273
10274	enum class MemberPointerConversionResult {
10275	Success,
10276	DifferentPointee,
10277	NotDerived,
10278	Ambiguous,
10279	Virtual,
10280	Inaccessible
10281	};
10282	enum class MemberPointerConversionDirection : bool { Downcast, Upcast };
10283	/// CheckMemberPointerConversion - Check the member pointer conversion from
10284	/// the expression From to the type ToType. This routine checks for ambiguous
10285	/// or virtual or inaccessible base-to-derived member pointer conversions for
10286	/// which IsMemberPointerConversion has already returned true. It produces a
10287	// diagnostic if there was an error.
10288	MemberPointerConversionResult CheckMemberPointerConversion(
10289	QualType FromType, const MemberPointerType *ToPtrType, CastKind &Kind,
10290	CXXCastPath &BasePath, SourceLocation CheckLoc, SourceRange OpRange,
10291	bool IgnoreBaseAccess, MemberPointerConversionDirection Direction);
10292
10293	/// IsQualificationConversion - Determines whether the conversion from
10294	/// an rvalue of type FromType to ToType is a qualification conversion
10295	/// (C++ 4.4).
10296	///
10297	/// \param ObjCLifetimeConversion Output parameter that will be set to
10298	/// indicate when the qualification conversion involves a change in the
10299	/// Objective-C object lifetime.
10300	bool IsQualificationConversion(QualType FromType, QualType ToType,
10301	bool CStyle, bool &ObjCLifetimeConversion);
10302
10303	/// Determine whether the conversion from FromType to ToType is a valid
10304	/// conversion of ExtInfo/ExtProtoInfo on the nested function type.
10305	/// More precisely, this method checks whether FromType can be transformed
10306	/// into an exact match for ToType, by transforming its extended function
10307	/// type information in legal manner (e.g. by strictly stripping "noreturn"
10308	/// or "noexcept", or by stripping "noescape" for arguments).
10309	bool IsFunctionConversion(QualType FromType, QualType ToType) const;
10310
10311	/// Same as `IsFunctionConversion`, but if this would return true, it sets
10312	/// `ResultTy` to `ToType`.
10313	bool TryFunctionConversion(QualType FromType, QualType ToType,
10314	QualType &ResultTy) const;
10315
10316	bool DiagnoseMultipleUserDefinedConversion(Expr *From, QualType ToType);
10317	void DiagnoseUseOfDeletedFunction(SourceLocation Loc, SourceRange Range,
10318	DeclarationName Name,
10319	OverloadCandidateSet &CandidateSet,
10320	FunctionDecl *Fn, MultiExprArg Args,
10321	bool IsMember = false);
10322
10323	ExprResult InitializeExplicitObjectArgument(Sema &S, Expr *Obj,
10324	FunctionDecl *Fun);
10325	ExprResult PerformImplicitObjectArgumentInitialization(
10326	Expr From, NestedNameSpecifier Qualifier, NamedDecl FoundDecl,
10327	CXXMethodDecl *Method);
10328
10329	/// PerformContextuallyConvertToBool - Perform a contextual conversion
10330	/// of the expression From to bool (C++0x [conv]p3).
10331	ExprResult PerformContextuallyConvertToBool(Expr *From);
10332
10333	/// PerformContextuallyConvertToObjCPointer - Perform a contextual
10334	/// conversion of the expression From to an Objective-C pointer type.
10335	/// Returns a valid but null ExprResult if no conversion sequence exists.
10336	ExprResult PerformContextuallyConvertToObjCPointer(Expr *From);
10337
10338	ExprResult BuildConvertedConstantExpression(Expr *From, QualType T,
10339	CCEKind CCE,
10340	NamedDecl Dest = nullptr*);
10341
10342	ExprResult CheckConvertedConstantExpression(Expr *From, QualType T,
10343	llvm::APSInt &Value, CCEKind CCE);
10344	ExprResult CheckConvertedConstantExpression(Expr *From, QualType T,
10345	APValue &Value, CCEKind CCE,
10346	NamedDecl Dest = nullptr*);
10347
10348	/// EvaluateConvertedConstantExpression - Evaluate an Expression
10349	/// That is a converted constant expression
10350	/// (which was built with BuildConvertedConstantExpression)
10351	ExprResult
10352	EvaluateConvertedConstantExpression(Expr *E, QualType T, APValue &Value,
10353	CCEKind CCE, bool RequireInt,
10354	const APValue &PreNarrowingValue);
10355
10356	/// Abstract base class used to perform a contextual implicit
10357	/// conversion from an expression to any type passing a filter.
10358	class ContextualImplicitConverter {
10359	public:
10360	bool Suppress;
10361	bool SuppressConversion;
10362
10363	ContextualImplicitConverter(bool Suppress = false,
10364	bool SuppressConversion = false)
10365	: Suppress(Suppress), SuppressConversion(SuppressConversion) {}
10366
10367	/// Determine whether the specified type is a valid destination type
10368	/// for this conversion.
10369	virtual bool match(QualType T) = `0`;
10370
10371	/// Emits a diagnostic complaining that the expression does not have
10372	/// integral or enumeration type.
10373	virtual SemaDiagnosticBuilder diagnoseNoMatch(Sema &S, SourceLocation Loc,
10374	QualType T) = `0`;
10375
10376	/// Emits a diagnostic when the expression has incomplete class type.
10377	virtual SemaDiagnosticBuilder
10378	diagnoseIncomplete(Sema &S, SourceLocation Loc, QualType T) = `0`;
10379
10380	/// Emits a diagnostic when the only matching conversion function
10381	/// is explicit.
10382	virtual SemaDiagnosticBuilder diagnoseExplicitConv(Sema &S,
10383	SourceLocation Loc,
10384	QualType T,
10385	QualType ConvTy) = `0`;
10386
10387	/// Emits a note for the explicit conversion function.
10388	virtual SemaDiagnosticBuilder
10389	noteExplicitConv(Sema &S, CXXConversionDecl *Conv, QualType ConvTy) = `0`;
10390
10391	/// Emits a diagnostic when there are multiple possible conversion
10392	/// functions.
10393	virtual SemaDiagnosticBuilder diagnoseAmbiguous(Sema &S, SourceLocation Loc,
10394	QualType T) = `0`;
10395
10396	/// Emits a note for one of the candidate conversions.
10397	virtual SemaDiagnosticBuilder
10398	noteAmbiguous(Sema &S, CXXConversionDecl *Conv, QualType ConvTy) = `0`;
10399
10400	/// Emits a diagnostic when we picked a conversion function
10401	/// (for cases when we are not allowed to pick a conversion function).
10402	virtual SemaDiagnosticBuilder diagnoseConversion(Sema &S,
10403	SourceLocation Loc,
10404	QualType T,
10405	QualType ConvTy) = `0`;
10406
10407	virtual ~ContextualImplicitConverter() {}
10408	};
10409
10410	class ICEConvertDiagnoser : public ContextualImplicitConverter {
10411	bool AllowScopedEnumerations;
10412
10413	public:
10414	ICEConvertDiagnoser(bool AllowScopedEnumerations, bool Suppress,
10415	bool SuppressConversion)
10416	: ContextualImplicitConverter (Suppress, SuppressConversion),
10417	AllowScopedEnumerations(AllowScopedEnumerations) {}
10418
10419	/// Match an integral or (possibly scoped) enumeration type.
10420	bool match(QualType T) override;
10421
10422	SemaDiagnosticBuilder diagnoseNoMatch(Sema &S, SourceLocation Loc,
10423	QualType T) override {
10424	return diagnoseNotInt(S, Loc, T);
10425	}
10426
10427	/// Emits a diagnostic complaining that the expression does not have
10428	/// integral or enumeration type.
10429	virtual SemaDiagnosticBuilder diagnoseNotInt(Sema &S, SourceLocation Loc,
10430	QualType T) = `0`;
10431	};
10432
10433	/// Perform a contextual implicit conversion.
10434	ExprResult
10435	PerformContextualImplicitConversion(SourceLocation Loc, Expr *FromE,
10436	ContextualImplicitConverter &Converter);
10437
10438	/// ReferenceCompareResult - Expresses the result of comparing two
10439	/// types (cv1 T1 and cv2 T2) to determine their compatibility for the
10440	/// purposes of initialization by reference (C++ [dcl.init.ref]p4).
10441	enum ReferenceCompareResult {
10442	/// Ref_Incompatible - The two types are incompatible, so direct
10443	/// reference binding is not possible.
10444	Ref_Incompatible = `0`,
10445	/// Ref_Related - The two types are reference-related, which means
10446	/// that their unqualified forms (T1 and T2) are either the same
10447	/// or T1 is a base class of T2.
10448	Ref_Related,
10449	/// Ref_Compatible - The two types are reference-compatible.
10450	Ref_Compatible
10451	};
10452
10453	// Fake up a scoped enumeration that still contextually converts to bool.
10454	struct ReferenceConversionsScope {
10455	/// The conversions that would be performed on an lvalue of type T2 when
10456	/// binding a reference of type T1 to it, as determined when evaluating
10457	/// whether T1 is reference-compatible with T2.
10458	enum ReferenceConversions {
10459	Qualification = `0x1`,
10460	NestedQualification = `0x2`,
10461	Function = `0x4`,
10462	DerivedToBase = `0x8`,
10463	ObjC = `0x10`,
10464	ObjCLifetime = `0x20`,
10465
10466	LLVM_MARK_AS_BITMASK_ENUM(/LargestValue=/ObjCLifetime)
10467	};
10468	};
10469	using ReferenceConversions = ReferenceConversionsScope::ReferenceConversions;
10470
10471	/// CompareReferenceRelationship - Compare the two types T1 and T2 to
10472	/// determine whether they are reference-compatible,
10473	/// reference-related, or incompatible, for use in C++ initialization by
10474	/// reference (C++ [dcl.ref.init]p4). Neither type can be a reference
10475	/// type, and the first type (T1) is the pointee type of the reference
10476	/// type being initialized.
10477	ReferenceCompareResult
10478	CompareReferenceRelationship(SourceLocation Loc, QualType T1, QualType T2,
10479	ReferenceConversions Conv = nullptr*);
10480
10481	/// AddOverloadCandidate - Adds the given function to the set of
10482	/// candidate functions, using the given function call arguments. If
10483	/// @p SuppressUserConversions, then don't allow user-defined
10484	/// conversions via constructors or conversion operators.
10485	///
10486	/// \param PartialOverloading true if we are performing "partial" overloading
10487	/// based on an incomplete set of function arguments. This feature is used by
10488	/// code completion.
10489	void AddOverloadCandidate(
10490	FunctionDecl Function, DeclAccessPair FoundDecl, ArrayRef<Expr > Args,
10491	OverloadCandidateSet &CandidateSet, bool SuppressUserConversions = false,
10492	bool PartialOverloading = false, bool AllowExplicit = true,
10493	bool AllowExplicitConversion = false,
10494	ADLCallKind IsADLCandidate = ADLCallKind::NotADL,
10495	ConversionSequenceList EarlyConversions = {},
10496	OverloadCandidateParamOrder PO = {},
10497	bool AggregateCandidateDeduction = false, bool StrictPackMatch = false);
10498
10499	/// Add all of the function declarations in the given function set to
10500	/// the overload candidate set.
10501	void AddFunctionCandidates(
10502	const UnresolvedSetImpl &Functions, ArrayRef<Expr *> Args,
10503	OverloadCandidateSet &CandidateSet,
10504	TemplateArgumentListInfo ExplicitTemplateArgs = nullptr*,
10505	bool SuppressUserConversions = false, bool PartialOverloading = false,
10506	bool FirstArgumentIsBase = false);
10507
10508	/// AddMethodCandidate - Adds a named decl (which is some kind of
10509	/// method) as a method candidate to the given overload set.
10510	void AddMethodCandidate(DeclAccessPair FoundDecl, QualType ObjectType,
10511	Expr::Classification ObjectClassification,
10512	ArrayRef<Expr *> Args,
10513	OverloadCandidateSet &CandidateSet,
10514	bool SuppressUserConversion = false,
10515	OverloadCandidateParamOrder PO = {});
10516
10517	/// AddMethodCandidate - Adds the given C++ member function to the set
10518	/// of candidate functions, using the given function call arguments
10519	/// and the object argument (@c Object). For example, in a call
10520	/// @c o.f(a1,a2), @c Object will contain @c o and @c Args will contain
10521	/// both @c a1 and @c a2. If @p SuppressUserConversions, then don't
10522	/// allow user-defined conversions via constructors or conversion
10523	/// operators.
10524	void AddMethodCandidate(CXXMethodDecl *Method, DeclAccessPair FoundDecl,
10525	CXXRecordDecl *ActingContext, QualType ObjectType,
10526	Expr::Classification ObjectClassification,
10527	ArrayRef<Expr *> Args,
10528	OverloadCandidateSet &CandidateSet,
10529	bool SuppressUserConversions = false,
10530	bool PartialOverloading = false,
10531	ConversionSequenceList EarlyConversions = {},
10532	OverloadCandidateParamOrder PO = {},
10533	bool StrictPackMatch = false);
10534
10535	/// Add a C++ member function template as a candidate to the candidate
10536	/// set, using template argument deduction to produce an appropriate member
10537	/// function template specialization.
10538	void AddMethodTemplateCandidate(
10539	FunctionTemplateDecl *MethodTmpl, DeclAccessPair FoundDecl,
10540	CXXRecordDecl *ActingContext,
10541	TemplateArgumentListInfo *ExplicitTemplateArgs, QualType ObjectType,
10542	Expr::Classification ObjectClassification, ArrayRef<Expr *> Args,
10543	OverloadCandidateSet &CandidateSet, bool SuppressUserConversions = false,
10544	bool PartialOverloading = false, OverloadCandidateParamOrder PO = {});
10545
10546	/// Add a C++ function template specialization as a candidate
10547	/// in the candidate set, using template argument deduction to produce
10548	/// an appropriate function template specialization.
10549	void AddTemplateOverloadCandidate(
10550	FunctionTemplateDecl *FunctionTemplate, DeclAccessPair FoundDecl,
10551	TemplateArgumentListInfo ExplicitTemplateArgs, ArrayRef<Expr > Args,
10552	OverloadCandidateSet &CandidateSet, bool SuppressUserConversions = false,
10553	bool PartialOverloading = false, bool AllowExplicit = true,
10554	ADLCallKind IsADLCandidate = ADLCallKind::NotADL,
10555	OverloadCandidateParamOrder PO = {},
10556	bool AggregateCandidateDeduction = false);
10557
10558	struct CheckNonDependentConversionsFlag {
10559	/// Do not consider any user-defined conversions when constructing the
10560	/// initializing sequence.
10561	bool SuppressUserConversions;
10562
10563	/// Before constructing the initializing sequence, we check whether the
10564	/// parameter type and argument type contain any user defined conversions.
10565	/// If so, do not initialize them. This effectively bypasses some undesired
10566	/// instantiation before checking constaints, which might otherwise result
10567	/// in non-SFINAE errors e.g. recursive constraints.
10568	bool OnlyInitializeNonUserDefinedConversions;
10569
10570	CheckNonDependentConversionsFlag(
10571	bool SuppressUserConversions,
10572	bool OnlyInitializeNonUserDefinedConversions)
10573	: SuppressUserConversions(SuppressUserConversions),
10574	OnlyInitializeNonUserDefinedConversions(
10575	OnlyInitializeNonUserDefinedConversions) {}
10576	};
10577
10578	/// Check that implicit conversion sequences can be formed for each argument
10579	/// whose corresponding parameter has a non-dependent type, per DR1391's
10580	/// [temp.deduct.call]p10.
10581	bool CheckNonDependentConversions(
10582	FunctionTemplateDecl *FunctionTemplate, ArrayRef<QualType> ParamTypes,
10583	ArrayRef<Expr *> Args, OverloadCandidateSet &CandidateSet,
10584	ConversionSequenceList &Conversions,
10585	CheckNonDependentConversionsFlag UserConversionFlag,
10586	CXXRecordDecl ActingContext = nullptr*, QualType ObjectType = QualType (),
10587	Expr::Classification ObjectClassification = {},
10588	OverloadCandidateParamOrder PO = {});
10589
10590	/// AddConversionCandidate - Add a C++ conversion function as a
10591	/// candidate in the candidate set (C++ [over.match.conv],
10592	/// C++ [over.match.copy]). From is the expression we're converting from,
10593	/// and ToType is the type that we're eventually trying to convert to
10594	/// (which may or may not be the same type as the type that the
10595	/// conversion function produces).
10596	void AddConversionCandidate(
10597	CXXConversionDecl *Conversion, DeclAccessPair FoundDecl,
10598	CXXRecordDecl ActingContext, Expr From, QualType ToType,
10599	OverloadCandidateSet &CandidateSet, bool AllowObjCConversionOnExplicit,
10600	bool AllowExplicit, bool AllowResultConversion = true,
10601	bool StrictPackMatch = false);
10602
10603	/// Adds a conversion function template specialization
10604	/// candidate to the overload set, using template argument deduction
10605	/// to deduce the template arguments of the conversion function
10606	/// template from the type that we are converting to (C++
10607	/// [temp.deduct.conv]).
10608	void AddTemplateConversionCandidate(
10609	FunctionTemplateDecl *FunctionTemplate, DeclAccessPair FoundDecl,
10610	CXXRecordDecl ActingContext, Expr From, QualType ToType,
10611	OverloadCandidateSet &CandidateSet, bool AllowObjCConversionOnExplicit,
10612	bool AllowExplicit, bool AllowResultConversion = true);
10613
10614	/// AddSurrogateCandidate - Adds a "surrogate" candidate function that
10615	/// converts the given @c Object to a function pointer via the
10616	/// conversion function @c Conversion, and then attempts to call it
10617	/// with the given arguments (C++ [over.call.object]p2-4). Proto is
10618	/// the type of function that we'll eventually be calling.
10619	void AddSurrogateCandidate(CXXConversionDecl *Conversion,
10620	DeclAccessPair FoundDecl,
10621	CXXRecordDecl *ActingContext,
10622	const FunctionProtoType Proto, Expr Object,
10623	ArrayRef<Expr *> Args,
10624	OverloadCandidateSet &CandidateSet);
10625
10626	/// Add all of the non-member operator function declarations in the given
10627	/// function set to the overload candidate set.
10628	void AddNonMemberOperatorCandidates(
10629	const UnresolvedSetImpl &Functions, ArrayRef<Expr *> Args,
10630	OverloadCandidateSet &CandidateSet,
10631	TemplateArgumentListInfo ExplicitTemplateArgs = nullptr*);
10632
10633	/// Add overload candidates for overloaded operators that are
10634	/// member functions.
10635	///
10636	/// Add the overloaded operator candidates that are member functions
10637	/// for the operator Op that was used in an operator expression such
10638	/// as "x Op y". , Args/NumArgs provides the operator arguments, and
10639	/// CandidateSet will store the added overload candidates. (C++
10640	/// [over.match.oper]).
10641	void AddMemberOperatorCandidates(OverloadedOperatorKind Op,
10642	SourceLocation OpLoc, ArrayRef<Expr *> Args,
10643	OverloadCandidateSet &CandidateSet,
10644	OverloadCandidateParamOrder PO = {});
10645
10646	/// AddBuiltinCandidate - Add a candidate for a built-in
10647	/// operator. ResultTy and ParamTys are the result and parameter types
10648	/// of the built-in candidate, respectively. Args and NumArgs are the
10649	/// arguments being passed to the candidate. IsAssignmentOperator
10650	/// should be true when this built-in candidate is an assignment
10651	/// operator. NumContextualBoolArguments is the number of arguments
10652	/// (at the beginning of the argument list) that will be contextually
10653	/// converted to bool.
10654	void AddBuiltinCandidate(QualType ParamTys, ArrayRef<Expr > Args,
10655	OverloadCandidateSet &CandidateSet,
10656	bool IsAssignmentOperator = false,
10657	unsigned NumContextualBoolArguments = `0`);
10658
10659	/// AddBuiltinOperatorCandidates - Add the appropriate built-in
10660	/// operator overloads to the candidate set (C++ [over.built]), based
10661	/// on the operator @p Op and the arguments given. For example, if the
10662	/// operator is a binary '+', this routine might add "int
10663	/// operator+(int, int)" to cover integer addition.
10664	void AddBuiltinOperatorCandidates(OverloadedOperatorKind Op,
10665	SourceLocation OpLoc, ArrayRef<Expr *> Args,
10666	OverloadCandidateSet &CandidateSet);
10667
10668	/// Add function candidates found via argument-dependent lookup
10669	/// to the set of overloading candidates.
10670	///
10671	/// This routine performs argument-dependent name lookup based on the
10672	/// given function name (which may also be an operator name) and adds
10673	/// all of the overload candidates found by ADL to the overload
10674	/// candidate set (C++ [basic.lookup.argdep]).
10675	void AddArgumentDependentLookupCandidates(
10676	DeclarationName Name, SourceLocation Loc, ArrayRef<Expr *> Args,
10677	TemplateArgumentListInfo *ExplicitTemplateArgs,
10678	OverloadCandidateSet &CandidateSet, bool PartialOverloading = false);
10679
10680	/// Check the enable_if expressions on the given function. Returns the first
10681	/// failing attribute, or NULL if they were all successful.
10682	EnableIfAttr CheckEnableIf(FunctionDecl Function, SourceLocation CallLoc,
10683	ArrayRef<Expr *> Args,
10684	bool MissingImplicitThis = false);
10685
10686	/// Emit diagnostics for the diagnose_if attributes on Function, ignoring any
10687	/// non-ArgDependent DiagnoseIfAttrs.
10688	///
10689	/// Argument-dependent diagnose_if attributes should be checked each time a
10690	/// function is used as a direct callee of a function call.
10691	///
10692	/// Returns true if any errors were emitted.
10693	bool diagnoseArgDependentDiagnoseIfAttrs(const FunctionDecl *Function,
10694	const Expr *ThisArg,
10695	ArrayRef<const Expr *> Args,
10696	SourceLocation Loc);
10697
10698	/// Emit diagnostics for the diagnose_if attributes on Function, ignoring any
10699	/// ArgDependent DiagnoseIfAttrs.
10700	///
10701	/// Argument-independent diagnose_if attributes should be checked on every use
10702	/// of a function.
10703	///
10704	/// Returns true if any errors were emitted.
10705	bool diagnoseArgIndependentDiagnoseIfAttrs(const NamedDecl *ND,
10706	SourceLocation Loc);
10707
10708	/// Determine if \p A and \p B are equivalent internal linkage declarations
10709	/// from different modules, and thus an ambiguity error can be downgraded to
10710	/// an extension warning.
10711	bool isEquivalentInternalLinkageDeclaration(const NamedDecl *A,
10712	const NamedDecl *B);
10713	void diagnoseEquivalentInternalLinkageDeclarations(
10714	SourceLocation Loc, const NamedDecl *D,
10715	ArrayRef<const NamedDecl *> Equiv);
10716
10717	// Emit as a 'note' the specific overload candidate
10718	void NoteOverloadCandidate(
10719	const NamedDecl Found, const* FunctionDecl *Fn,
10720	OverloadCandidateRewriteKind RewriteKind = OverloadCandidateRewriteKind(),
10721	QualType DestType = QualType (), bool TakingAddress = false);
10722
10723	// Emit as a series of 'note's all template and non-templates identified by
10724	// the expression Expr
10725	void NoteAllOverloadCandidates(Expr *E, QualType DestType = QualType (),
10726	bool TakingAddress = false);
10727
10728	/// Returns whether the given function's address can be taken or not,
10729	/// optionally emitting a diagnostic if the address can't be taken.
10730	///
10731	/// Returns false if taking the address of the function is illegal.
10732	bool checkAddressOfFunctionIsAvailable(const FunctionDecl *Function,
10733	bool Complain = false,
10734	SourceLocation Loc = SourceLocation ());
10735
10736	// [PossiblyAFunctionType] --> [Return]
10737	// NonFunctionType --> NonFunctionType
10738	// R (A) --> R(A)
10739	// R ()(A) --> R (A)*
10740	// R (&)(A) --> R (A)
10741	// R (S::)(A) --> R (A)*
10742	QualType ExtractUnqualifiedFunctionType(QualType PossiblyAFunctionType);
10743
10744	/// ResolveAddressOfOverloadedFunction - Try to resolve the address of
10745	/// an overloaded function (C++ [over.over]), where @p From is an
10746	/// expression with overloaded function type and @p ToType is the type
10747	/// we're trying to resolve to. For example:
10748	///
10749	/// @code
10750	/// int f(double);
10751	/// int f(int);
10752	///
10753	/// int (pfd)(double) = f; // selects f(double)*
10754	/// @endcode
10755	///
10756	/// This routine returns the resulting FunctionDecl if it could be
10757	/// resolved, and NULL otherwise. When @p Complain is true, this
10758	/// routine will emit diagnostics if there is an error.
10759	FunctionDecl *
10760	ResolveAddressOfOverloadedFunction(Expr *AddressOfExpr, QualType TargetType,
10761	bool Complain, DeclAccessPair &Found,
10762	bool pHadMultipleCandidates = nullptr*);
10763
10764	/// Given an expression that refers to an overloaded function, try to
10765	/// resolve that function to a single function that can have its address
10766	/// taken. This will modify `Pair` iff it returns non-null.
10767	///
10768	/// This routine can only succeed if from all of the candidates in the
10769	/// overload set for SrcExpr that can have their addresses taken, there is one
10770	/// candidate that is more constrained than the rest.
10771	FunctionDecl *
10772	resolveAddressOfSingleOverloadCandidate(Expr *E, DeclAccessPair &FoundResult);
10773
10774	/// Given an overloaded function, tries to turn it into a non-overloaded
10775	/// function reference using resolveAddressOfSingleOverloadCandidate. This
10776	/// will perform access checks, diagnose the use of the resultant decl, and,
10777	/// if requested, potentially perform a function-to-pointer decay.
10778	///
10779	/// Returns false if resolveAddressOfSingleOverloadCandidate fails.
10780	/// Otherwise, returns true. This may emit diagnostics and return true.
10781	bool resolveAndFixAddressOfSingleOverloadCandidate(
10782	ExprResult &SrcExpr, bool DoFunctionPointerConversion = false);
10783
10784	/// Given an expression that refers to an overloaded function, try to
10785	/// resolve that overloaded function expression down to a single function.
10786	///
10787	/// This routine can only resolve template-ids that refer to a single function
10788	/// template, where that template-id refers to a single template whose
10789	/// template arguments are either provided by the template-id or have
10790	/// defaults, as described in C++0x [temp.arg.explicit]p3.
10791	///
10792	/// If no template-ids are found, no diagnostics are emitted and NULL is
10793	/// returned.
10794	FunctionDecl *ResolveSingleFunctionTemplateSpecialization(
10795	OverloadExpr ovl, bool* Complain = false, DeclAccessPair Found = nullptr*,
10796	TemplateSpecCandidateSet FailedTSC = nullptr*,
10797	bool ForTypeDeduction = false);
10798
10799	// Resolve and fix an overloaded expression that can be resolved
10800	// because it identifies a single function template specialization.
10801	//
10802	// Last three arguments should only be supplied if Complain = true
10803	//
10804	// Return true if it was logically possible to so resolve the
10805	// expression, regardless of whether or not it succeeded. Always
10806	// returns true if 'complain' is set.
10807	bool ResolveAndFixSingleFunctionTemplateSpecialization(
10808	ExprResult &SrcExpr, bool DoFunctionPointerConversion = false,
10809	bool Complain = false, SourceRange OpRangeForComplaining = SourceRange (),
10810	QualType DestTypeForComplaining = QualType (),
10811	unsigned DiagIDForComplaining = `0`);
10812
10813	/// Add the overload candidates named by callee and/or found by argument
10814	/// dependent lookup to the given overload set.
10815	void AddOverloadedCallCandidates(UnresolvedLookupExpr *ULE,
10816	ArrayRef<Expr *> Args,
10817	OverloadCandidateSet &CandidateSet,
10818	bool PartialOverloading = false);
10819
10820	/// Add the call candidates from the given set of lookup results to the given
10821	/// overload set. Non-function lookup results are ignored.
10822	void AddOverloadedCallCandidates(
10823	LookupResult &R, TemplateArgumentListInfo *ExplicitTemplateArgs,
10824	ArrayRef<Expr *> Args, OverloadCandidateSet &CandidateSet);
10825
10826	// An enum used to represent the different possible results of building a
10827	// range-based for loop.
10828	enum ForRangeStatus {
10829	FRS_Success,
10830	FRS_NoViableFunction,
10831	FRS_DiagnosticIssued
10832	};
10833
10834	/// Build a call to 'begin' or 'end' for a C++11 for-range statement. If the
10835	/// given LookupResult is non-empty, it is assumed to describe a member which
10836	/// will be invoked. Otherwise, the function will be found via argument
10837	/// dependent lookup.
10838	/// CallExpr is set to a valid expression and FRS_Success returned on success,
10839	/// otherwise CallExpr is set to ExprError() and some non-success value
10840	/// is returned.
10841	ForRangeStatus BuildForRangeBeginEndCall(SourceLocation Loc,
10842	SourceLocation RangeLoc,
10843	const DeclarationNameInfo &NameInfo,
10844	LookupResult &MemberLookup,
10845	OverloadCandidateSet *CandidateSet,
10846	Expr Range, ExprResult CallExpr);
10847
10848	/// BuildOverloadedCallExpr - Given the call expression that calls Fn
10849	/// (which eventually refers to the declaration Func) and the call
10850	/// arguments Args/NumArgs, attempt to resolve the function call down
10851	/// to a specific function. If overload resolution succeeds, returns
10852	/// the call expression produced by overload resolution.
10853	/// Otherwise, emits diagnostics and returns ExprError.
10854	ExprResult BuildOverloadedCallExpr(
10855	Scope S, Expr Fn, UnresolvedLookupExpr *ULE, SourceLocation LParenLoc,
10856	MultiExprArg Args, SourceLocation RParenLoc, Expr *ExecConfig,
10857	bool AllowTypoCorrection = true, bool CalleesAddressIsTaken = false);
10858
10859	/// Constructs and populates an OverloadedCandidateSet from
10860	/// the given function.
10861	/// \returns true when an the ExprResult output parameter has been set.
10862	bool buildOverloadedCallSet(Scope S, Expr Fn, UnresolvedLookupExpr *ULE,
10863	MultiExprArg Args, SourceLocation RParenLoc,
10864	OverloadCandidateSet *CandidateSet,
10865	ExprResult *Result);
10866
10867	ExprResult CreateUnresolvedLookupExpr(CXXRecordDecl *NamingClass,
10868	NestedNameSpecifierLoc NNSLoc,
10869	DeclarationNameInfo DNI,
10870	const UnresolvedSetImpl &Fns,
10871	bool PerformADL = true);
10872
10873	/// Perform lookup for an overloaded unary operator.
10874	void LookupOverloadedUnaryOp(OverloadCandidateSet &CandidateSet,
10875	OverloadedOperatorKind Op,
10876	const UnresolvedSetImpl &Fns,
10877	ArrayRef<Expr > Args, bool* RequiresADL = true);
10878
10879	/// Create a unary operation that may resolve to an overloaded
10880	/// operator.
10881	///
10882	/// \param OpLoc The location of the operator itself (e.g., '').*
10883	///
10884	/// \param Opc The UnaryOperatorKind that describes this operator.
10885	///
10886	/// \param Fns The set of non-member functions that will be
10887	/// considered by overload resolution. The caller needs to build this
10888	/// set based on the context using, e.g.,
10889	/// LookupOverloadedOperatorName() and ArgumentDependentLookup(). This
10890	/// set should not contain any member functions; those will be added
10891	/// by CreateOverloadedUnaryOp().
10892	///
10893	/// \param Input The input argument.
10894	ExprResult CreateOverloadedUnaryOp(SourceLocation OpLoc,
10895	UnaryOperatorKind Opc,
10896	const UnresolvedSetImpl &Fns, Expr *input,
10897	bool RequiresADL = true);
10898
10899	/// Perform lookup for an overloaded binary operator.
10900	void LookupOverloadedBinOp(OverloadCandidateSet &CandidateSet,
10901	OverloadedOperatorKind Op,
10902	const UnresolvedSetImpl &Fns,
10903	ArrayRef<Expr > Args, bool* RequiresADL = true);
10904
10905	/// Create a binary operation that may resolve to an overloaded
10906	/// operator.
10907	///
10908	/// \param OpLoc The location of the operator itself (e.g., '+').
10909	///
10910	/// \param Opc The BinaryOperatorKind that describes this operator.
10911	///
10912	/// \param Fns The set of non-member functions that will be
10913	/// considered by overload resolution. The caller needs to build this
10914	/// set based on the context using, e.g.,
10915	/// LookupOverloadedOperatorName() and ArgumentDependentLookup(). This
10916	/// set should not contain any member functions; those will be added
10917	/// by CreateOverloadedBinOp().
10918	///
10919	/// \param LHS Left-hand argument.
10920	/// \param RHS Right-hand argument.
10921	/// \param PerformADL Whether to consider operator candidates found by ADL.
10922	/// \param AllowRewrittenCandidates Whether to consider candidates found by
10923	/// C++20 operator rewrites.
10924	/// \param DefaultedFn If we are synthesizing a defaulted operator function,
10925	/// the function in question. Such a function is never a candidate in
10926	/// our overload resolution. This also enables synthesizing a three-way
10927	/// comparison from < and == as described in C++20 [class.spaceship]p1.
10928	ExprResult CreateOverloadedBinOp(SourceLocation OpLoc, BinaryOperatorKind Opc,
10929	const UnresolvedSetImpl &Fns, Expr *LHS,
10930	Expr RHS, bool* RequiresADL = true,
10931	bool AllowRewrittenCandidates = true,
10932	FunctionDecl DefaultedFn = nullptr*);
10933	ExprResult BuildSynthesizedThreeWayComparison(SourceLocation OpLoc,
10934	const UnresolvedSetImpl &Fns,
10935	Expr LHS, Expr RHS,
10936	FunctionDecl *DefaultedFn);
10937
10938	ExprResult CreateOverloadedArraySubscriptExpr(SourceLocation LLoc,
10939	SourceLocation RLoc, Expr *Base,
10940	MultiExprArg Args);
10941
10942	/// BuildCallToMemberFunction - Build a call to a member
10943	/// function. MemExpr is the expression that refers to the member
10944	/// function (and includes the object parameter), Args/NumArgs are the
10945	/// arguments to the function call (not including the object
10946	/// parameter). The caller needs to validate that the member
10947	/// expression refers to a non-static member function or an overloaded
10948	/// member function.
10949	ExprResult BuildCallToMemberFunction(
10950	Scope S, Expr MemExpr, SourceLocation LParenLoc, MultiExprArg Args,
10951	SourceLocation RParenLoc, Expr ExecConfig = nullptr*,
10952	bool IsExecConfig = false, bool AllowRecovery = false);
10953
10954	/// BuildCallToObjectOfClassType - Build a call to an object of class
10955	/// type (C++ [over.call.object]), which can end up invoking an
10956	/// overloaded function call operator (@c operator()) or performing a
10957	/// user-defined conversion on the object argument.
10958	ExprResult BuildCallToObjectOfClassType(Scope S, Expr Object,
10959	SourceLocation LParenLoc,
10960	MultiExprArg Args,
10961	SourceLocation RParenLoc);
10962
10963	/// BuildOverloadedArrowExpr - Build a call to an overloaded @c operator->
10964	/// (if one exists), where @c Base is an expression of class type and
10965	/// @c Member is the name of the member we're trying to find.
10966	ExprResult BuildOverloadedArrowExpr(Scope S, Expr Base,
10967	SourceLocation OpLoc,
10968	bool NoArrowOperatorFound = nullptr*);
10969
10970	ExprResult BuildCXXMemberCallExpr(Expr Exp, NamedDecl FoundDecl,
10971	CXXConversionDecl *Method,
10972	bool HadMultipleCandidates);
10973
10974	/// BuildLiteralOperatorCall - Build a UserDefinedLiteral by creating a call
10975	/// to a literal operator described by the provided lookup results.
10976	ExprResult BuildLiteralOperatorCall(
10977	LookupResult &R, DeclarationNameInfo &SuffixInfo, ArrayRef<Expr *> Args,
10978	SourceLocation LitEndLoc,
10979	TemplateArgumentListInfo ExplicitTemplateArgs = nullptr*);
10980
10981	/// FixOverloadedFunctionReference - E is an expression that refers to
10982	/// a C++ overloaded function (possibly with some parentheses and
10983	/// perhaps a '&' around it). We have resolved the overloaded function
10984	/// to the function declaration Fn, so patch up the expression E to
10985	/// refer (possibly indirectly) to Fn. Returns the new expr.
10986	ExprResult FixOverloadedFunctionReference(Expr *E, DeclAccessPair FoundDecl,
10987	FunctionDecl *Fn);
10988	ExprResult FixOverloadedFunctionReference(ExprResult,
10989	DeclAccessPair FoundDecl,
10990	FunctionDecl *Fn);
10991
10992	/// - Returns a selector which best matches given argument list or
10993	/// nullptr if none could be found
10994	ObjCMethodDecl *SelectBestMethod(Selector Sel, MultiExprArg Args,
10995	bool IsInstance,
10996	SmallVectorImpl<ObjCMethodDecl *> &Methods);
10997
10998	///@}
10999
11000	//
11001	//
11002	// -------------------------------------------------------------------------
11003	//
11004	//
11005
11006	/// \name Statements
11007	/// Implementations are in SemaStmt.cpp
11008	///@{
11009
11010	public:
11011	/// Stack of active SEH __finally scopes. Can be empty.
11012	SmallVector<Scope *, `2`> CurrentSEHFinally;
11013
11014	/// Stack of '_Defer' statements that are currently being parsed, as well
11015	/// as the locations of their '_Defer' keywords. Can be empty.
11016	SmallVector<std::pair<Scope *, SourceLocation>, `2`> CurrentDefer;
11017
11018	StmtResult ActOnExprStmt(ExprResult Arg, bool DiscardedValue = true);
11019	StmtResult ActOnExprStmtError();
11020
11021	StmtResult ActOnNullStmt(SourceLocation SemiLoc,
11022	bool HasLeadingEmptyMacro = false);
11023
11024	StmtResult ActOnDeclStmt(DeclGroupPtrTy Decl, SourceLocation StartLoc,
11025	SourceLocation EndLoc);
11026	void ActOnForEachDeclStmt(DeclGroupPtrTy Decl);
11027
11028	/// DiagnoseUnusedExprResult - If the statement passed in is an expression
11029	/// whose result is unused, warn.
11030	void DiagnoseUnusedExprResult(const Stmt S, unsigned* DiagID);
11031
11032	void ActOnStartOfCompoundStmt(bool IsStmtExpr);
11033	void ActOnAfterCompoundStatementLeadingPragmas();
11034	void ActOnFinishOfCompoundStmt();
11035	StmtResult ActOnCompoundStmt(SourceLocation L, SourceLocation R,
11036	ArrayRef<Stmt > Elts, bool* isStmtExpr);
11037
11038	sema::CompoundScopeInfo &getCurCompoundScope() const;
11039
11040	ExprResult ActOnCaseExpr(SourceLocation CaseLoc, ExprResult Val);
11041	StmtResult ActOnCaseStmt(SourceLocation CaseLoc, ExprResult LHS,
11042	SourceLocation DotDotDotLoc, ExprResult RHS,
11043	SourceLocation ColonLoc);
11044
11045	/// ActOnCaseStmtBody - This installs a statement as the body of a case.
11046	void ActOnCaseStmtBody(Stmt CaseStmt, Stmt SubStmt);
11047
11048	StmtResult ActOnDefaultStmt(SourceLocation DefaultLoc,
11049	SourceLocation ColonLoc, Stmt *SubStmt,
11050	Scope *CurScope);
11051	StmtResult ActOnLabelStmt(SourceLocation IdentLoc, LabelDecl *TheDecl,
11052	SourceLocation ColonLoc, Stmt *SubStmt);
11053
11054	StmtResult BuildAttributedStmt(SourceLocation AttrsLoc,
11055	ArrayRef<const Attr > Attrs, Stmt SubStmt);
11056	StmtResult ActOnAttributedStmt(const ParsedAttributes &AttrList,
11057	Stmt *SubStmt);
11058
11059	/// Check whether the given statement can have musttail applied to it,
11060	/// issuing a diagnostic and returning false if not. In the success case,
11061	/// the statement is rewritten to remove implicit nodes from the return
11062	/// value.
11063	bool checkAndRewriteMustTailAttr(Stmt St, const* Attr &MTA);
11064
11065	StmtResult ActOnIfStmt(SourceLocation IfLoc, IfStatementKind StatementKind,
11066	SourceLocation LParenLoc, Stmt *InitStmt,
11067	ConditionResult Cond, SourceLocation RParenLoc,
11068	Stmt ThenVal, SourceLocation ElseLoc, Stmt ElseVal);
11069	StmtResult BuildIfStmt(SourceLocation IfLoc, IfStatementKind StatementKind,
11070	SourceLocation LParenLoc, Stmt *InitStmt,
11071	ConditionResult Cond, SourceLocation RParenLoc,
11072	Stmt ThenVal, SourceLocation ElseLoc, Stmt ElseVal);
11073
11074	ExprResult CheckSwitchCondition(SourceLocation SwitchLoc, Expr *Cond);
11075
11076	StmtResult ActOnStartOfSwitchStmt(SourceLocation SwitchLoc,
11077	SourceLocation LParenLoc, Stmt *InitStmt,
11078	ConditionResult Cond,
11079	SourceLocation RParenLoc);
11080	StmtResult ActOnFinishSwitchStmt(SourceLocation SwitchLoc, Stmt *Switch,
11081	Stmt *Body);
11082
11083	/// DiagnoseAssignmentEnum - Warn if assignment to enum is a constant
11084	/// integer not in the range of enum values.
11085	void DiagnoseAssignmentEnum(QualType DstType, QualType SrcType,
11086	Expr *SrcExpr);
11087
11088	StmtResult ActOnWhileStmt(SourceLocation WhileLoc, SourceLocation LParenLoc,
11089	ConditionResult Cond, SourceLocation RParenLoc,
11090	Stmt *Body);
11091	StmtResult ActOnDoStmt(SourceLocation DoLoc, Stmt *Body,
11092	SourceLocation WhileLoc, SourceLocation CondLParen,
11093	Expr *Cond, SourceLocation CondRParen);
11094
11095	StmtResult ActOnForStmt(SourceLocation ForLoc, SourceLocation LParenLoc,
11096	Stmt *First, ConditionResult Second,
11097	FullExprArg Third, SourceLocation RParenLoc,
11098	Stmt *Body);
11099
11100	/// In an Objective C collection iteration statement:
11101	/// for (x in y)
11102	/// x can be an arbitrary l-value expression. Bind it up as a
11103	/// full-expression.
11104	StmtResult ActOnForEachLValueExpr(Expr *E);
11105
11106	enum BuildForRangeKind {
11107	/// Initial building of a for-range statement.
11108	BFRK_Build,
11109	/// Instantiation or recovery rebuild of a for-range statement. Don't
11110	/// attempt any typo-correction.
11111	BFRK_Rebuild,
11112	/// Determining whether a for-range statement could be built. Avoid any
11113	/// unnecessary or irreversible actions.
11114	BFRK_Check
11115	};
11116
11117	/// ActOnCXXForRangeStmt - Check and build a C++11 for-range statement.
11118	///
11119	/// C++11 [stmt.ranged]:
11120	/// A range-based for statement is equivalent to
11121	///
11122	/// {
11123	/// auto && __range = range-init;
11124	/// for ( auto __begin = begin-expr,
11125	/// __end = end-expr;
11126	/// __begin != __end;
11127	/// ++__begin ) {
11128	/// for-range-declaration = __begin;*
11129	/// statement
11130	/// }
11131	/// }
11132	///
11133	/// The body of the loop is not available yet, since it cannot be analysed
11134	/// until we have determined the type of the for-range-declaration.
11135	StmtResult ActOnCXXForRangeStmt(
11136	Scope *S, SourceLocation ForLoc, SourceLocation CoawaitLoc,
11137	Stmt InitStmt, Stmt LoopVar, SourceLocation ColonLoc, Expr *Collection,
11138	SourceLocation RParenLoc, BuildForRangeKind Kind,
11139	ArrayRef<MaterializeTemporaryExpr *> LifetimeExtendTemps = {});
11140
11141	/// BuildCXXForRangeStmt - Build or instantiate a C++11 for-range statement.
11142	StmtResult BuildCXXForRangeStmt(
11143	SourceLocation ForLoc, SourceLocation CoawaitLoc, Stmt *InitStmt,
11144	SourceLocation ColonLoc, Stmt RangeDecl, Stmt Begin, Stmt *End,
11145	Expr Cond, Expr Inc, Stmt *LoopVarDecl, SourceLocation RParenLoc,
11146	BuildForRangeKind Kind,
11147	ArrayRef<MaterializeTemporaryExpr *> LifetimeExtendTemps = {});
11148
11149	/// Set the type of a for-range declaration whose for-range or expansion
11150	/// initialiser is dependent.
11151	void ActOnDependentForRangeInitializer(VarDecl *LoopVar,
11152	BuildForRangeKind BFRK);
11153
11154	/// Holds the 'begin' and 'end' variables of a range-based for loop or
11155	/// expansion statement; begin-expr and end-expr are also provided; the
11156	/// latter are used in some diagnostics.
11157	struct ForRangeBeginEndInfo {
11158	VarDecl BeginVar = nullptr*;
11159	VarDecl EndVar = nullptr*;
11160	Expr BeginExpr = nullptr*;
11161	Expr EndExpr = nullptr*;
11162	bool isValid() const { return BeginVar != nullptr && EndVar != nullptr; }
11163	};
11164
11165	/// Determine begin-expr and end-expr and build variable declarations for
11166	/// them as per [stmt.ranged].
11167	ForRangeBeginEndInfo BuildCXXForRangeBeginEndVars(
11168	Scope S, VarDecl RangeVar, SourceLocation ColonLoc,
11169	SourceLocation CoawaitLoc,
11170	ArrayRef<MaterializeTemporaryExpr *> LifetimeExtendTemps,
11171	BuildForRangeKind Kind, bool IsConstexpr,
11172	StmtResult RebuildResult = nullptr*,
11173	llvm::function_ref<StmtResult()> RebuildWithDereference = {},
11174	IdentifierInfo BeginName = nullptr, IdentifierInfo EndName = nullptr);
11175
11176	/// Helper used by the expansion statements and for-range code to build
11177	/// a variable declaration for e.g. 'begin' and 'end'.
11178	VarDecl *BuildForRangeVarDecl(SourceLocation Loc, QualType Type,
11179	IdentifierInfo Name, bool* IsConstexpr);
11180
11181	/// Build the range variable of a range-based for loop or iterating
11182	/// expansion statement and return its DeclStmt.
11183	StmtResult BuildCXXForRangeRangeVar(Scope S, Expr Range, QualType Type,
11184	bool IsConstexpr = false);
11185
11186	/// FinishCXXForRangeStmt - Attach the body to a C++0x for-range statement.
11187	/// This is a separate step from ActOnCXXForRangeStmt because analysis of the
11188	/// body cannot be performed until after the type of the range variable is
11189	/// determined.
11190	StmtResult FinishCXXForRangeStmt(Stmt ForRange, Stmt Body);
11191
11192	StmtResult ActOnGotoStmt(SourceLocation GotoLoc, SourceLocation LabelLoc,
11193	LabelDecl *TheDecl);
11194	StmtResult ActOnIndirectGotoStmt(SourceLocation GotoLoc,
11195	SourceLocation StarLoc, Expr *DestExp);
11196	StmtResult ActOnContinueStmt(SourceLocation ContinueLoc, Scope *CurScope,
11197	LabelDecl *Label, SourceLocation LabelLoc);
11198	StmtResult ActOnBreakStmt(SourceLocation BreakLoc, Scope *CurScope,
11199	LabelDecl *Label, SourceLocation LabelLoc);
11200
11201	void ActOnStartOfDeferStmt(SourceLocation DeferLoc, Scope *CurScope);
11202	void ActOnDeferStmtError(Scope *CurScope);
11203	StmtResult ActOnEndOfDeferStmt(Stmt Body, Scope CurScope);
11204
11205	struct NamedReturnInfo {
11206	const VarDecl *Candidate;
11207
11208	enum Status : uint8_t { None, MoveEligible, MoveEligibleAndCopyElidable };
11209	Status S;
11210
11211	bool isMoveEligible() const { return S != None; };
11212	bool isCopyElidable() const { return S == MoveEligibleAndCopyElidable; }
11213	};
11214	enum class SimplerImplicitMoveMode { ForceOff, Normal, ForceOn };
11215
11216	/// Determine whether the given expression might be move-eligible or
11217	/// copy-elidable in either a (co_)return statement or throw expression,
11218	/// without considering function return type, if applicable.
11219	///
11220	/// \param E The expression being returned from the function or block,
11221	/// being thrown, or being co_returned from a coroutine. This expression
11222	/// might be modified by the implementation.
11223	///
11224	/// \param Mode Overrides detection of current language mode
11225	/// and uses the rules for C++23.
11226	///
11227	/// \returns An aggregate which contains the Candidate and isMoveEligible
11228	/// and isCopyElidable methods. If Candidate is non-null, it means
11229	/// isMoveEligible() would be true under the most permissive language
11230	/// standard.
11231	NamedReturnInfo getNamedReturnInfo(
11232	Expr *&E, SimplerImplicitMoveMode Mode = SimplerImplicitMoveMode::Normal);
11233
11234	/// Determine whether the given NRVO candidate variable is move-eligible or
11235	/// copy-elidable, without considering function return type.
11236	///
11237	/// \param VD The NRVO candidate variable.
11238	///
11239	/// \returns An aggregate which contains the Candidate and isMoveEligible
11240	/// and isCopyElidable methods. If Candidate is non-null, it means
11241	/// isMoveEligible() would be true under the most permissive language
11242	/// standard.
11243	NamedReturnInfo getNamedReturnInfo(const VarDecl *VD);
11244
11245	/// Updates given NamedReturnInfo's move-eligible and
11246	/// copy-elidable statuses, considering the function
11247	/// return type criteria as applicable to return statements.
11248	///
11249	/// \param Info The NamedReturnInfo object to update.
11250	///
11251	/// \param ReturnType This is the return type of the function.
11252	/// \returns The copy elision candidate, in case the initial return expression
11253	/// was copy elidable, or nullptr otherwise.
11254	const VarDecl *getCopyElisionCandidate(NamedReturnInfo &Info,
11255	QualType ReturnType);
11256
11257	/// Perform the initialization of a potentially-movable value, which
11258	/// is the result of return value.
11259	///
11260	/// This routine implements C++20 [class.copy.elision]p3, which attempts to
11261	/// treat returned lvalues as rvalues in certain cases (to prefer move
11262	/// construction), then falls back to treating them as lvalues if that failed.
11263	ExprResult
11264	PerformMoveOrCopyInitialization(const InitializedEntity &Entity,
11265	const NamedReturnInfo &NRInfo, Expr *Value,
11266	bool SupressSimplerImplicitMoves = false);
11267
11268	TypeLoc getReturnTypeLoc(FunctionDecl FD) const*;
11269
11270	/// Deduce the return type for a function from a returned expression, per
11271	/// C++1y [dcl.spec.auto]p6.
11272	bool DeduceFunctionTypeFromReturnExpr(FunctionDecl *FD,
11273	SourceLocation ReturnLoc, Expr *RetExpr,
11274	const AutoType *AT);
11275
11276	StmtResult ActOnReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp,
11277	Scope *CurScope);
11278	StmtResult BuildReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp,
11279	bool AllowRecovery = false);
11280
11281	/// ActOnCapScopeReturnStmt - Utility routine to type-check return statements
11282	/// for capturing scopes.
11283	StmtResult ActOnCapScopeReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp,
11284	NamedReturnInfo &NRInfo,
11285	bool SupressSimplerImplicitMoves);
11286
11287	/// ActOnCXXCatchBlock - Takes an exception declaration and a handler block
11288	/// and creates a proper catch handler from them.
11289	StmtResult ActOnCXXCatchBlock(SourceLocation CatchLoc, Decl *ExDecl,
11290	Stmt *HandlerBlock);
11291
11292	/// ActOnCXXTryBlock - Takes a try compound-statement and a number of
11293	/// handlers and creates a try statement from them.
11294	StmtResult ActOnCXXTryBlock(SourceLocation TryLoc, Stmt *TryBlock,
11295	ArrayRef<Stmt *> Handlers);
11296
11297	void DiagnoseExceptionUse(SourceLocation Loc, bool IsTry);
11298
11299	StmtResult ActOnSEHTryBlock(bool IsCXXTry, // try (true) or __try (false) ?
11300	SourceLocation TryLoc, Stmt *TryBlock,
11301	Stmt *Handler);
11302	StmtResult ActOnSEHExceptBlock(SourceLocation Loc, Expr *FilterExpr,
11303	Stmt *Block);
11304	void ActOnStartSEHFinallyBlock();
11305	void ActOnAbortSEHFinallyBlock();
11306	StmtResult ActOnFinishSEHFinallyBlock(SourceLocation Loc, Stmt *Block);
11307	StmtResult ActOnSEHLeaveStmt(SourceLocation Loc, Scope *CurScope);
11308
11309	StmtResult BuildMSDependentExistsStmt(SourceLocation KeywordLoc,
11310	bool IsIfExists,
11311	NestedNameSpecifierLoc QualifierLoc,
11312	DeclarationNameInfo NameInfo,
11313	Stmt *Nested);
11314	StmtResult ActOnMSDependentExistsStmt(SourceLocation KeywordLoc,
11315	bool IsIfExists, CXXScopeSpec &SS,
11316	UnqualifiedId &Name, Stmt *Nested);
11317
11318	void ActOnCapturedRegionStart(SourceLocation Loc, Scope *CurScope,
11319	CapturedRegionKind Kind, unsigned NumParams);
11320	typedef std::pair<StringRef, QualType> CapturedParamNameType;
11321	void ActOnCapturedRegionStart(SourceLocation Loc, Scope *CurScope,
11322	CapturedRegionKind Kind,
11323	ArrayRef<CapturedParamNameType> Params,
11324	unsigned OpenMPCaptureLevel = `0`);
11325	StmtResult ActOnCapturedRegionEnd(Stmt *S);
11326	void ActOnCapturedRegionError();
11327	RecordDecl CreateCapturedStmtRecordDecl(CapturedDecl &CD,
11328	SourceLocation Loc,
11329	unsigned NumParams);
11330
11331	void ApplyForRangeOrExpansionStatementLifetimeExtension(
11332	VarDecl RangeVar, ArrayRef<MaterializeTemporaryExpr > Temporaries);
11333
11334	private:
11335	/// Check whether the given statement can have musttail applied to it,
11336	/// issuing a diagnostic and returning false if not.
11337	bool checkMustTailAttr(const Stmt St, const* Attr &MTA);
11338
11339	///@}
11340
11341	//
11342	//
11343	// -------------------------------------------------------------------------
11344	//
11345	//
11346
11347	/// \name `inline asm` Statement
11348	/// Implementations are in SemaStmtAsm.cpp
11349	///@{
11350
11351	public:
11352	ExprResult ActOnGCCAsmStmtString(Expr Stm, bool* ForAsmLabel);
11353	StmtResult ActOnGCCAsmStmt(SourceLocation AsmLoc, bool IsSimple,
11354	bool IsVolatile, unsigned NumOutputs,
11355	unsigned NumInputs, IdentifierInfo **Names,
11356	MultiExprArg Constraints, MultiExprArg Exprs,
11357	Expr *AsmString, MultiExprArg Clobbers,
11358	unsigned NumLabels, SourceLocation RParenLoc);
11359
11360	void FillInlineAsmIdentifierInfo(Expr *Res,
11361	llvm::InlineAsmIdentifierInfo &Info);
11362	ExprResult LookupInlineAsmIdentifier(CXXScopeSpec &SS,
11363	SourceLocation TemplateKWLoc,
11364	UnqualifiedId &Id,
11365	bool IsUnevaluatedContext);
11366	bool LookupInlineAsmField(StringRef Base, StringRef Member, unsigned &Offset,
11367	SourceLocation AsmLoc);
11368	ExprResult LookupInlineAsmVarDeclField(Expr *RefExpr, StringRef Member,
11369	SourceLocation AsmLoc);
11370	StmtResult ActOnMSAsmStmt(SourceLocation AsmLoc, SourceLocation LBraceLoc,
11371	ArrayRef<Token> AsmToks, StringRef AsmString,
11372	unsigned NumOutputs, unsigned NumInputs,
11373	ArrayRef<StringRef> Constraints,
11374	ArrayRef<StringRef> Clobbers,
11375	ArrayRef<Expr *> Exprs, SourceLocation EndLoc);
11376	LabelDecl *GetOrCreateMSAsmLabel(StringRef ExternalLabelName,
11377	SourceLocation Location, bool AlwaysCreate);
11378
11379	///@}
11380
11381	//
11382	//
11383	// -------------------------------------------------------------------------
11384	//
11385	//
11386
11387	/// \name Statement Attribute Handling
11388	/// Implementations are in SemaStmtAttr.cpp
11389	///@{
11390
11391	public:
11392	bool CheckNoInlineAttr(const Stmt OrigSt, const* Stmt *CurSt,
11393	const AttributeCommonInfo &A);
11394	bool CheckAlwaysInlineAttr(const Stmt OrigSt, const* Stmt *CurSt,
11395	const AttributeCommonInfo &A);
11396
11397	CodeAlignAttr BuildCodeAlignAttr(const* AttributeCommonInfo &CI, Expr *E);
11398	bool CheckRebuiltStmtAttributes(ArrayRef<const Attr *> Attrs);
11399
11400	/// Process the attributes before creating an attributed statement. Returns
11401	/// the semantic attributes that have been processed.
11402	void ProcessStmtAttributes(Stmt Stmt, const* ParsedAttributes &InAttrs,
11403	SmallVectorImpl<const Attr *> &OutAttrs);
11404
11405	ExprResult ActOnCXXAssumeAttr(Stmt St, const* ParsedAttr &A,
11406	SourceRange Range);
11407	ExprResult BuildCXXAssumeExpr(Expr *Assumption,
11408	const IdentifierInfo *AttrName,
11409	SourceRange Range);
11410
11411	///@}
11412
11413	//
11414	//
11415	// -------------------------------------------------------------------------
11416	//
11417	//
11418
11419	/// \name C++ Templates
11420	/// Implementations are in SemaTemplate.cpp
11421	///@{
11422
11423	public:
11424	// Saves the current floating-point pragma stack and clear it in this Sema.
11425	class FpPragmaStackSaveRAII {
11426	public:
11427	FpPragmaStackSaveRAII(Sema &S)
11428	: S(S), SavedStack (std::move(S.FpPragmaStack)) {
11429	S.FpPragmaStack.Stack.clear();
11430	}
11431	~FpPragmaStackSaveRAII() { S.FpPragmaStack = std::move(SavedStack); }
11432	FpPragmaStackSaveRAII(const FpPragmaStackSaveRAII &) = delete;
11433	FpPragmaStackSaveRAII &operator=(const FpPragmaStackSaveRAII &) = delete;
11434
11435	private:
11436	Sema &S;
11437	PragmaStack<FPOptionsOverride> SavedStack;
11438	};
11439
11440	void resetFPOptions(FPOptions FPO) {
11441	CurFPFeatures = FPO;
11442	FpPragmaStack.CurrentValue = FPO.getChangesFrom(Base: FPOptions (LangOpts));
11443	}
11444
11445	ArrayRef<InventedTemplateParameterInfo> getInventedParameterInfos() const {
11446	return llvm::ArrayRef(InventedParameterInfos.begin() +
11447	InventedParameterInfosStart,
11448	InventedParameterInfos.end());
11449	}
11450
11451	ArrayRef<sema::FunctionScopeInfo > getFunctionScopes() const* {
11452	return llvm::ArrayRef(FunctionScopes.begin() + FunctionScopesStart,
11453	FunctionScopes.end());
11454	}
11455
11456	typedef llvm::MapVector<const FunctionDecl *,
11457	std::unique_ptr<LateParsedTemplate>>
11458	LateParsedTemplateMapT;
11459	LateParsedTemplateMapT LateParsedTemplateMap;
11460
11461	/// Determine the number of levels of enclosing template parameters. This is
11462	/// only usable while parsing. Note that this does not include dependent
11463	/// contexts in which no template parameters have yet been declared, such as
11464	/// in a terse function template or generic lambda before the first 'auto' is
11465	/// encountered.
11466	unsigned getTemplateDepth(Scope S) const*;
11467
11468	void FilterAcceptableTemplateNames(LookupResult &R,
11469	bool AllowFunctionTemplates = true,
11470	bool AllowDependent = true);
11471	bool hasAnyAcceptableTemplateNames(LookupResult &R,
11472	bool AllowFunctionTemplates = true,
11473	bool AllowDependent = true,
11474	bool AllowNonTemplateFunctions = false);
11475	/// Try to interpret the lookup result D as a template-name.
11476	///
11477	/// \param D A declaration found by name lookup.
11478	/// \param AllowFunctionTemplates Whether function templates should be
11479	/// considered valid results.
11480	/// \param AllowDependent Whether unresolved using declarations (that might
11481	/// name templates) should be considered valid results.
11482	static NamedDecl getAsTemplateNameDecl(NamedDecl D,
11483	bool AllowFunctionTemplates = true,
11484	bool AllowDependent = true);
11485
11486	enum TemplateNameIsRequiredTag { TemplateNameIsRequired };
11487	/// Whether and why a template name is required in this lookup.
11488	class RequiredTemplateKind {
11489	public:
11490	/// Template name is required if TemplateKWLoc is valid.
11491	RequiredTemplateKind(SourceLocation TemplateKWLoc = SourceLocation ())
11492	: TemplateKW (TemplateKWLoc) {}
11493	/// Template name is unconditionally required.
11494	RequiredTemplateKind(TemplateNameIsRequiredTag) {}
11495
11496	SourceLocation getTemplateKeywordLoc() const {
11497	return TemplateKW.value_or(u: SourceLocation ());
11498	}
11499	bool hasTemplateKeyword() const {
11500	return getTemplateKeywordLoc().isValid();
11501	}
11502	bool isRequired() const { return TemplateKW != SourceLocation (); }
11503	explicit operator bool() const { return isRequired(); }
11504
11505	private:
11506	std::optional<SourceLocation> TemplateKW;
11507	};
11508
11509	enum class AssumedTemplateKind {
11510	/// This is not assumed to be a template name.
11511	None,
11512	/// This is assumed to be a template name because lookup found nothing.
11513	FoundNothing,
11514	/// This is assumed to be a template name because lookup found one or more
11515	/// functions (but no function templates).
11516	FoundFunctions,
11517	};
11518
11519	bool
11520	LookupTemplateName(LookupResult &R, Scope *S, CXXScopeSpec &SS,
11521	QualType ObjectType, bool EnteringContext,
11522	RequiredTemplateKind RequiredTemplate = SourceLocation (),
11523	AssumedTemplateKind ATK = nullptr*,
11524	bool AllowTypoCorrection = true);
11525
11526	TemplateNameKind isTemplateName(Scope *S, CXXScopeSpec &SS,
11527	bool hasTemplateKeyword,
11528	const UnqualifiedId &Name,
11529	ParsedType ObjectType, bool EnteringContext,
11530	TemplateTy &Template,
11531	bool &MemberOfUnknownSpecialization,
11532	bool AllowTypoCorrection = true);
11533
11534	/// Try to resolve an undeclared template name as a type template.
11535	///
11536	/// Sets II to the identifier corresponding to the template name, and updates
11537	/// Name to a corresponding (typo-corrected) type template name and TNK to
11538	/// the corresponding kind, if possible.
11539	void ActOnUndeclaredTypeTemplateName(Scope *S, TemplateTy &Name,
11540	TemplateNameKind &TNK,
11541	SourceLocation NameLoc,
11542	IdentifierInfo *&II);
11543
11544	/// Determine whether a particular identifier might be the name in a C++1z
11545	/// deduction-guide declaration.
11546	bool isDeductionGuideName(Scope S, const* IdentifierInfo &Name,
11547	SourceLocation NameLoc, CXXScopeSpec &SS,
11548	ParsedTemplateTy Template = nullptr*);
11549
11550	bool DiagnoseUnknownTemplateName(const IdentifierInfo &II,
11551	SourceLocation IILoc, Scope *S,
11552	const CXXScopeSpec *SS,
11553	TemplateTy &SuggestedTemplate,
11554	TemplateNameKind &SuggestedKind);
11555
11556	/// Determine whether we would be unable to instantiate this template (because
11557	/// it either has no definition, or is in the process of being instantiated).
11558	bool DiagnoseUninstantiableTemplate(
11559	SourceLocation PointOfInstantiation, NamedDecl *Instantiation,
11560	bool InstantiatedFromMember, const NamedDecl *Pattern,
11561	const NamedDecl *PatternDef, TemplateSpecializationKind TSK,
11562	bool Complain = true, bool Unreachable = nullptr*);
11563
11564	/// DiagnoseTemplateParameterShadow - Produce a diagnostic complaining
11565	/// that the template parameter 'PrevDecl' is being shadowed by a new
11566	/// declaration at location Loc. Returns true to indicate that this is
11567	/// an error, and false otherwise.
11568	///
11569	/// \param Loc The location of the declaration that shadows a template
11570	/// parameter.
11571	///
11572	/// \param PrevDecl The template parameter that the declaration shadows.
11573	///
11574	/// \param SupportedForCompatibility Whether to issue the diagnostic as
11575	/// a warning for compatibility with older versions of clang.
11576	/// Ignored when MSVC compatibility is enabled.
11577	void DiagnoseTemplateParameterShadow(SourceLocation Loc, Decl *PrevDecl,
11578	bool SupportedForCompatibility = false);
11579
11580	/// AdjustDeclIfTemplate - If the given decl happens to be a template, reset
11581	/// the parameter D to reference the templated declaration and return a
11582	/// pointer to the template declaration. Otherwise, do nothing to D and return
11583	/// null.
11584	TemplateDecl AdjustDeclIfTemplate(Decl &Decl);
11585
11586	/// ActOnTypeParameter - Called when a C++ template type parameter
11587	/// (e.g., "typename T") has been parsed. Typename specifies whether
11588	/// the keyword "typename" was used to declare the type parameter
11589	/// (otherwise, "class" was used), and KeyLoc is the location of the
11590	/// "class" or "typename" keyword. ParamName is the name of the
11591	/// parameter (NULL indicates an unnamed template parameter) and
11592	/// ParamNameLoc is the location of the parameter name (if any).
11593	/// If the type parameter has a default argument, it will be added
11594	/// later via ActOnTypeParameterDefault.
11595	NamedDecl ActOnTypeParameter(Scope S, bool Typename,
11596	SourceLocation EllipsisLoc,
11597	SourceLocation KeyLoc,
11598	IdentifierInfo *ParamName,
11599	SourceLocation ParamNameLoc, unsigned Depth,
11600	unsigned Position, SourceLocation EqualLoc,
11601	ParsedType DefaultArg, bool HasTypeConstraint);
11602
11603	bool CheckTypeConstraint(TemplateIdAnnotation *TypeConstraint);
11604
11605	bool ActOnTypeConstraint(const CXXScopeSpec &SS,
11606	TemplateIdAnnotation *TypeConstraint,
11607	TemplateTypeParmDecl *ConstrainedParameter,
11608	SourceLocation EllipsisLoc);
11609	bool BuildTypeConstraint(const CXXScopeSpec &SS,
11610	TemplateIdAnnotation *TypeConstraint,
11611	TemplateTypeParmDecl *ConstrainedParameter,
11612	SourceLocation EllipsisLoc,
11613	bool AllowUnexpandedPack);
11614
11615	/// Attach a type-constraint to a template parameter.
11616	/// \returns true if an error occurred. This can happen if the
11617	/// immediately-declared constraint could not be formed (e.g. incorrect number
11618	/// of arguments for the named concept).
11619	bool AttachTypeConstraint(NestedNameSpecifierLoc NS,
11620	DeclarationNameInfo NameInfo,
11621	TemplateName NamedConcept, NamedDecl *FoundDecl,
11622	const TemplateArgumentListInfo *TemplateArgs,
11623	TemplateTypeParmDecl *ConstrainedParameter,
11624	SourceLocation EllipsisLoc);
11625
11626	bool AttachTypeConstraint(AutoTypeLoc TL,
11627	NonTypeTemplateParmDecl *NewConstrainedParm,
11628	NonTypeTemplateParmDecl *OrigConstrainedParm,
11629	SourceLocation EllipsisLoc);
11630
11631	/// Require the given type to be a structural type, and diagnose if it is not.
11632	///
11633	/// \return \c true if an error was produced.
11634	bool RequireStructuralType(QualType T, SourceLocation Loc);
11635
11636	/// Check that the type of a non-type template parameter is
11637	/// well-formed.
11638	///
11639	/// \returns the (possibly-promoted) parameter type if valid;
11640	/// otherwise, produces a diagnostic and returns a NULL type.
11641	QualType CheckNonTypeTemplateParameterType(TypeSourceInfo *&TSI,
11642	SourceLocation Loc);
11643	QualType CheckNonTypeTemplateParameterType(QualType T, SourceLocation Loc);
11644
11645	NamedDecl ActOnNonTypeTemplateParameter(Scope S, Declarator &D,
11646	unsigned Depth, unsigned Position,
11647	SourceLocation EqualLoc,
11648	Expr *DefaultArg);
11649
11650	/// ActOnTemplateTemplateParameter - Called when a C++ template template
11651	/// parameter (e.g. T in template <template \<typename> class T> class array)
11652	/// has been parsed. S is the current scope.
11653	NamedDecl *ActOnTemplateTemplateParameter(
11654	Scope *S, SourceLocation TmpLoc, TemplateNameKind Kind,
11655	bool TypenameKeyword, TemplateParameterList *Params,
11656	SourceLocation EllipsisLoc, IdentifierInfo *ParamName,
11657	SourceLocation ParamNameLoc, unsigned Depth, unsigned Position,
11658	SourceLocation EqualLoc, ParsedTemplateArgument DefaultArg);
11659
11660	/// ActOnTemplateParameterList - Builds a TemplateParameterList, optionally
11661	/// constrained by RequiresClause, that contains the template parameters in
11662	/// Params.
11663	TemplateParameterList *ActOnTemplateParameterList(
11664	unsigned Depth, SourceLocation ExportLoc, SourceLocation TemplateLoc,
11665	SourceLocation LAngleLoc, ArrayRef<NamedDecl *> Params,
11666	SourceLocation RAngleLoc, Expr *RequiresClause);
11667
11668	/// The context in which we are checking a template parameter list.
11669	enum TemplateParamListContext {
11670	// For this context, Class, Variable, TypeAlias, and non-pack Template
11671	// Template Parameters are treated uniformly.
11672	TPC_Other,
11673
11674	TPC_FunctionTemplate,
11675	TPC_ClassTemplateMember,
11676	TPC_FriendClassTemplate,
11677	TPC_FriendFunctionTemplate,
11678	TPC_FriendFunctionTemplateDefinition,
11679	TPC_TemplateTemplateParameterPack,
11680	};
11681
11682	/// Checks the validity of a template parameter list, possibly
11683	/// considering the template parameter list from a previous
11684	/// declaration.
11685	///
11686	/// If an "old" template parameter list is provided, it must be
11687	/// equivalent (per TemplateParameterListsAreEqual) to the "new"
11688	/// template parameter list.
11689	///
11690	/// \param NewParams Template parameter list for a new template
11691	/// declaration. This template parameter list will be updated with any
11692	/// default arguments that are carried through from the previous
11693	/// template parameter list.
11694	///
11695	/// \param OldParams If provided, template parameter list from a
11696	/// previous declaration of the same template. Default template
11697	/// arguments will be merged from the old template parameter list to
11698	/// the new template parameter list.
11699	///
11700	/// \param TPC Describes the context in which we are checking the given
11701	/// template parameter list.
11702	///
11703	/// \param SkipBody If we might have already made a prior merged definition
11704	/// of this template visible, the corresponding body-skipping information.
11705	/// Default argument redefinition is not an error when skipping such a body,
11706	/// because (under the ODR) we can assume the default arguments are the same
11707	/// as the prior merged definition.
11708	///
11709	/// \returns true if an error occurred, false otherwise.
11710	bool CheckTemplateParameterList(TemplateParameterList *NewParams,
11711	TemplateParameterList *OldParams,
11712	TemplateParamListContext TPC,
11713	SkipBodyInfo SkipBody = nullptr*);
11714
11715	/// Match the given template parameter lists to the given scope
11716	/// specifier, returning the template parameter list that applies to the
11717	/// name.
11718	///
11719	/// \param DeclStartLoc the start of the declaration that has a scope
11720	/// specifier or a template parameter list.
11721	///
11722	/// \param DeclLoc The location of the declaration itself.
11723	///
11724	/// \param SS the scope specifier that will be matched to the given template
11725	/// parameter lists. This scope specifier precedes a qualified name that is
11726	/// being declared.
11727	///
11728	/// \param TemplateId The template-id following the scope specifier, if there
11729	/// is one. Used to check for a missing 'template<>'.
11730	///
11731	/// \param ParamLists the template parameter lists, from the outermost to the
11732	/// innermost template parameter lists.
11733	///
11734	/// \param IsFriend Whether to apply the slightly different rules for
11735	/// matching template parameters to scope specifiers in friend
11736	/// declarations.
11737	///
11738	/// \param IsMemberSpecialization will be set true if the scope specifier
11739	/// denotes a fully-specialized type, and therefore this is a declaration of
11740	/// a member specialization.
11741	///
11742	/// \returns the template parameter list, if any, that corresponds to the
11743	/// name that is preceded by the scope specifier @p SS. This template
11744	/// parameter list may have template parameters (if we're declaring a
11745	/// template) or may have no template parameters (if we're declaring a
11746	/// template specialization), or may be NULL (if what we're declaring isn't
11747	/// itself a template).
11748	TemplateParameterList *MatchTemplateParametersToScopeSpecifier(
11749	SourceLocation DeclStartLoc, SourceLocation DeclLoc,
11750	const CXXScopeSpec &SS, TemplateIdAnnotation *TemplateId,
11751	ArrayRef<TemplateParameterList > ParamLists, bool* IsFriend,
11752	bool &IsMemberSpecialization, bool &Invalid,
11753	bool SuppressDiagnostic = false);
11754
11755	/// Returns the template parameter list with all default template argument
11756	/// information.
11757	TemplateParameterList GetTemplateParameterList(TemplateDecl TD);
11758
11759	DeclResult CheckClassTemplate(
11760	Scope S, unsigned* TagSpec, TagUseKind TUK, SourceLocation KWLoc,
11761	CXXScopeSpec &SS, IdentifierInfo *Name, SourceLocation NameLoc,
11762	const ParsedAttributesView &Attr, TemplateParameterList *TemplateParams,
11763	AccessSpecifier AS, SourceLocation ModulePrivateLoc,
11764	SourceLocation FriendLoc, unsigned NumOuterTemplateParamLists,
11765	TemplateParameterList **OuterTemplateParamLists,
11766	bool IsMemberSpecialization, SkipBodyInfo SkipBody = nullptr*);
11767
11768	/// Translates template arguments as provided by the parser
11769	/// into template arguments used by semantic analysis.
11770	void translateTemplateArguments(const ASTTemplateArgsPtr &In,
11771	TemplateArgumentListInfo &Out);
11772
11773	/// Convert a parsed type into a parsed template argument. This is mostly
11774	/// trivial, except that we may have parsed a C++17 deduced class template
11775	/// specialization type, in which case we should form a template template
11776	/// argument instead of a type template argument.
11777	ParsedTemplateArgument ActOnTemplateTypeArgument(TypeResult ParsedType);
11778
11779	void NoteAllFoundTemplates(TemplateName Name);
11780
11781	QualType CheckTemplateIdType(ElaboratedTypeKeyword Keyword,
11782	TemplateName Template,
11783	SourceLocation TemplateLoc,
11784	TemplateArgumentListInfo &TemplateArgs,
11785	Scope Scope, bool* ForNestedNameSpecifier);
11786
11787	TypeResult
11788	ActOnTemplateIdType(Scope *S, ElaboratedTypeKeyword ElaboratedKeyword,
11789	SourceLocation ElaboratedKeywordLoc, CXXScopeSpec &SS,
11790	SourceLocation TemplateKWLoc, TemplateTy Template,
11791	const IdentifierInfo *TemplateII,
11792	SourceLocation TemplateIILoc, SourceLocation LAngleLoc,
11793	ASTTemplateArgsPtr TemplateArgs, SourceLocation RAngleLoc,
11794	bool IsCtorOrDtorName = false, bool IsClassName = false,
11795	ImplicitTypenameContext AllowImplicitTypename =
11796	ImplicitTypenameContext::No);
11797
11798	/// Parsed an elaborated-type-specifier that refers to a template-id,
11799	/// such as \c class T::template apply<U>.
11800	TypeResult ActOnTagTemplateIdType(
11801	TagUseKind TUK, TypeSpecifierType TagSpec, SourceLocation TagLoc,
11802	CXXScopeSpec &SS, SourceLocation TemplateKWLoc, TemplateTy TemplateD,
11803	SourceLocation TemplateLoc, SourceLocation LAngleLoc,
11804	ASTTemplateArgsPtr TemplateArgsIn, SourceLocation RAngleLoc);
11805
11806	DeclResult ActOnVarTemplateSpecialization(
11807	Scope S, Declarator &D, TypeSourceInfo TSI, LookupResult &Previous,
11808	SourceLocation TemplateKWLoc, TemplateParameterList *TemplateParams,
11809	StorageClass SC, bool IsPartialSpecialization);
11810
11811	/// Get the specialization of the given variable template corresponding to
11812	/// the specified argument list, or a null-but-valid result if the arguments
11813	/// are dependent.
11814	DeclResult CheckVarTemplateId(VarTemplateDecl *Template,
11815	SourceLocation TemplateLoc,
11816	SourceLocation TemplateNameLoc,
11817	const TemplateArgumentListInfo &TemplateArgs,
11818	bool SetWrittenArgs);
11819
11820	/// Form a reference to the specialization of the given variable template
11821	/// corresponding to the specified argument list, or a null-but-valid result
11822	/// if the arguments are dependent.
11823	ExprResult CheckVarTemplateId(const CXXScopeSpec &SS,
11824	const DeclarationNameInfo &NameInfo,
11825	VarTemplateDecl Template, NamedDecl FoundD,
11826	SourceLocation TemplateLoc,
11827	const TemplateArgumentListInfo *TemplateArgs);
11828
11829	ExprResult CheckVarOrConceptTemplateTemplateId(
11830	const DeclarationNameInfo &NameInfo, TemplateName Template,
11831	const TemplateArgumentListInfo *TemplateArgs);
11832
11833	ExprResult
11834	CheckConceptTemplateId(const CXXScopeSpec &SS, SourceLocation TemplateKWLoc,
11835	const DeclarationNameInfo &ConceptNameInfo,
11836	NamedDecl FoundDecl, TemplateDecl NamedConcept,
11837	const TemplateArgumentListInfo *TemplateArgs,
11838	bool DoCheckConstraintSatisfaction = true);
11839
11840	void diagnoseMissingTemplateArguments(TemplateName Name, SourceLocation Loc);
11841	void diagnoseMissingTemplateArguments(const CXXScopeSpec &SS,
11842	bool TemplateKeyword, TemplateDecl *TD,
11843	SourceLocation Loc);
11844
11845	ExprResult BuildTemplateIdExpr(const CXXScopeSpec &SS,
11846	SourceLocation TemplateKWLoc, LookupResult &R,
11847	bool RequiresADL,
11848	const TemplateArgumentListInfo *TemplateArgs);
11849
11850	// We actually only call this from template instantiation.
11851	ExprResult
11852	BuildQualifiedTemplateIdExpr(CXXScopeSpec &SS, SourceLocation TemplateKWLoc,
11853	const DeclarationNameInfo &NameInfo,
11854	const TemplateArgumentListInfo *TemplateArgs,
11855	bool IsAddressOfOperand);
11856
11857	UnsignedOrNone getPackIndex(TemplateArgument Pack) const {
11858	return Pack.pack_size() - `1` - *ArgPackSubstIndex;
11859	}
11860
11861	TemplateArgument
11862	getPackSubstitutedTemplateArgument(TemplateArgument Arg) const {
11863	Arg = Arg.pack_elements()[*ArgPackSubstIndex];
11864	if (Arg.isPackExpansion())
11865	Arg = Arg.getPackExpansionPattern();
11866	return Arg;
11867	}
11868
11869	ExprResult
11870	BuildSubstNonTypeTemplateParmExpr(Decl AssociatedDecl, unsigned* Index,
11871	QualType ParamType, SourceLocation loc,
11872	TemplateArgument Replacement,
11873	UnsignedOrNone PackIndex, bool Final);
11874
11875	/// Form a template name from a name that is syntactically required to name a
11876	/// template, either due to use of the 'template' keyword or because a name in
11877	/// this syntactic context is assumed to name a template (C++
11878	/// [temp.names]p2-4).
11879	///
11880	/// This action forms a template name given the name of the template and its
11881	/// optional scope specifier. This is used when the 'template' keyword is used
11882	/// or when the parsing context unambiguously treats a following '<' as
11883	/// introducing a template argument list. Note that this may produce a
11884	/// non-dependent template name if we can perform the lookup now and identify
11885	/// the named template.
11886	///
11887	/// For example, given "x.MetaFun::template apply", the scope specifier
11888	/// \p SS will be "MetaFun::", \p TemplateKWLoc contains the location
11889	/// of the "template" keyword, and "apply" is the \p Name.
11890	TemplateNameKind ActOnTemplateName(Scope *S, CXXScopeSpec &SS,
11891	SourceLocation TemplateKWLoc,
11892	const UnqualifiedId &Name,
11893	ParsedType ObjectType,
11894	bool EnteringContext, TemplateTy &Template,
11895	bool AllowInjectedClassName = false);
11896
11897	DeclResult ActOnClassTemplateSpecialization(
11898	Scope S, unsigned* TagSpec, TagUseKind TUK, SourceLocation KWLoc,
11899	SourceLocation ModulePrivateLoc, CXXScopeSpec &SS,
11900	TemplateIdAnnotation &TemplateId, const ParsedAttributesView &Attr,
11901	MultiTemplateParamsArg TemplateParameterLists,
11902	SkipBodyInfo SkipBody = nullptr*);
11903
11904	/// Check the non-type template arguments of a class template
11905	/// partial specialization according to C++ [temp.class.spec]p9.
11906	///
11907	/// \param TemplateNameLoc the location of the template name.
11908	/// \param PrimaryTemplate the template parameters of the primary class
11909	/// template.
11910	/// \param NumExplicit the number of explicitly-specified template arguments.
11911	/// \param TemplateArgs the template arguments of the class template
11912	/// partial specialization.
11913	///
11914	/// \returns \c true if there was an error, \c false otherwise.
11915	bool CheckTemplatePartialSpecializationArgs(SourceLocation Loc,
11916	TemplateDecl *PrimaryTemplate,
11917	unsigned NumExplicitArgs,
11918	ArrayRef<TemplateArgument> Args);
11919	void CheckTemplatePartialSpecialization(
11920	ClassTemplatePartialSpecializationDecl *Partial);
11921	void CheckTemplatePartialSpecialization(
11922	VarTemplatePartialSpecializationDecl *Partial);
11923
11924	Decl ActOnTemplateDeclarator(Scope S,
11925	MultiTemplateParamsArg TemplateParameterLists,
11926	Declarator &D);
11927
11928	/// Diagnose cases where we have an explicit template specialization
11929	/// before/after an explicit template instantiation, producing diagnostics
11930	/// for those cases where they are required and determining whether the
11931	/// new specialization/instantiation will have any effect.
11932	///
11933	/// \param NewLoc the location of the new explicit specialization or
11934	/// instantiation.
11935	///
11936	/// \param NewTSK the kind of the new explicit specialization or
11937	/// instantiation.
11938	///
11939	/// \param PrevDecl the previous declaration of the entity.
11940	///
11941	/// \param PrevTSK the kind of the old explicit specialization or
11942	/// instantiatin.
11943	///
11944	/// \param PrevPointOfInstantiation if valid, indicates where the previous
11945	/// declaration was instantiated (either implicitly or explicitly).
11946	///
11947	/// \param HasNoEffect will be set to true to indicate that the new
11948	/// specialization or instantiation has no effect and should be ignored.
11949	///
11950	/// \returns true if there was an error that should prevent the introduction
11951	/// of the new declaration into the AST, false otherwise.
11952	bool CheckSpecializationInstantiationRedecl(
11953	SourceLocation NewLoc,
11954	TemplateSpecializationKind ActOnExplicitInstantiationNewTSK,
11955	NamedDecl *PrevDecl, TemplateSpecializationKind PrevTSK,
11956	SourceLocation PrevPtOfInstantiation, bool &SuppressNew);
11957
11958	/// Perform semantic analysis for the given dependent function
11959	/// template specialization.
11960	///
11961	/// The only possible way to get a dependent function template specialization
11962	/// is with a friend declaration, like so:
11963	///
11964	/// \code
11965	/// template \<class T> void foo(T);
11966	/// template \<class T> class A {
11967	/// friend void foo<>(T);
11968	/// };
11969	/// \endcode
11970	///
11971	/// There really isn't any useful analysis we can do here, so we
11972	/// just store the information.
11973	bool CheckDependentFunctionTemplateSpecialization(
11974	FunctionDecl FD, const* TemplateArgumentListInfo *ExplicitTemplateArgs,
11975	LookupResult &Previous);
11976
11977	/// Perform semantic analysis for the given function template
11978	/// specialization.
11979	///
11980	/// This routine performs all of the semantic analysis required for an
11981	/// explicit function template specialization. On successful completion,
11982	/// the function declaration \p FD will become a function template
11983	/// specialization.
11984	///
11985	/// \param FD the function declaration, which will be updated to become a
11986	/// function template specialization.
11987	///
11988	/// \param ExplicitTemplateArgs the explicitly-provided template arguments,
11989	/// if any. Note that this may be valid info even when 0 arguments are
11990	/// explicitly provided as in, e.g., \c void sort<>(char, char);
11991	/// as it anyway contains info on the angle brackets locations.
11992	///
11993	/// \param Previous the set of declarations that may be specialized by
11994	/// this function specialization.
11995	///
11996	/// \param QualifiedFriend whether this is a lookup for a qualified friend
11997	/// declaration with no explicit template argument list that might be
11998	/// befriending a function template specialization.
11999	bool CheckFunctionTemplateSpecialization(
12000	FunctionDecl FD, TemplateArgumentListInfo ExplicitTemplateArgs,
12001	LookupResult &Previous, bool QualifiedFriend = false);
12002
12003	/// Perform semantic analysis for the given non-template member
12004	/// specialization.
12005	///
12006	/// This routine performs all of the semantic analysis required for an
12007	/// explicit member function specialization. On successful completion,
12008	/// the function declaration \p FD will become a member function
12009	/// specialization.
12010	///
12011	/// \param Member the member declaration, which will be updated to become a
12012	/// specialization.
12013	///
12014	/// \param Previous the set of declarations, one of which may be specialized
12015	/// by this function specialization; the set will be modified to contain the
12016	/// redeclared member.
12017	bool CheckMemberSpecialization(NamedDecl *Member, LookupResult &Previous);
12018	void CompleteMemberSpecialization(NamedDecl *Member, LookupResult &Previous);
12019
12020	// Explicit instantiation of a class template specialization
12021	DeclResult ActOnExplicitInstantiation(
12022	Scope *S, SourceLocation ExternLoc, SourceLocation TemplateLoc,
12023	unsigned TagSpec, SourceLocation KWLoc, const CXXScopeSpec &SS,
12024	TemplateTy Template, SourceLocation TemplateNameLoc,
12025	SourceLocation LAngleLoc, ASTTemplateArgsPtr TemplateArgs,
12026	SourceLocation RAngleLoc, const ParsedAttributesView &Attr);
12027
12028	// Explicit instantiation of a member class of a class template.
12029	DeclResult ActOnExplicitInstantiation(Scope *S, SourceLocation ExternLoc,
12030	SourceLocation TemplateLoc,
12031	unsigned TagSpec, SourceLocation KWLoc,
12032	CXXScopeSpec &SS, IdentifierInfo *Name,
12033	SourceLocation NameLoc,
12034	const ParsedAttributesView &Attr);
12035
12036	DeclResult ActOnExplicitInstantiation(Scope *S, SourceLocation ExternLoc,
12037	SourceLocation TemplateLoc,
12038	Declarator &D);
12039
12040	/// If the given template parameter has a default template
12041	/// argument, substitute into that default template argument and
12042	/// return the corresponding template argument.
12043	TemplateArgumentLoc SubstDefaultTemplateArgumentIfAvailable(
12044	TemplateDecl *Template, SourceLocation TemplateKWLoc,
12045	SourceLocation TemplateNameLoc, SourceLocation RAngleLoc, Decl *Param,
12046	ArrayRef<TemplateArgument> SugaredConverted,
12047	ArrayRef<TemplateArgument> CanonicalConverted, bool &HasDefaultArg);
12048
12049	/// Returns the top most location responsible for the definition of \p N.
12050	/// If \p N is a a template specialization, this is the location
12051	/// of the top of the instantiation stack.
12052	/// Otherwise, the location of \p N is returned.
12053	SourceLocation getTopMostPointOfInstantiation(const NamedDecl ) const*;
12054
12055	/// Specifies the context in which a particular template
12056	/// argument is being checked.
12057	enum CheckTemplateArgumentKind {
12058	/// The template argument was specified in the code or was
12059	/// instantiated with some deduced template arguments.
12060	CTAK_Specified,
12061
12062	/// The template argument was deduced via template argument
12063	/// deduction.
12064	CTAK_Deduced,
12065
12066	/// The template argument was deduced from an array bound
12067	/// via template argument deduction.
12068	CTAK_DeducedFromArrayBound
12069	};
12070
12071	struct CheckTemplateArgumentInfo {
12072	explicit CheckTemplateArgumentInfo(bool PartialOrdering = false,
12073	bool MatchingTTP = false)
12074	: PartialOrdering(PartialOrdering), MatchingTTP(MatchingTTP) {}
12075	CheckTemplateArgumentInfo(const CheckTemplateArgumentInfo &) = delete;
12076	CheckTemplateArgumentInfo &
12077	operator=(const CheckTemplateArgumentInfo &) = delete;
12078
12079	/// The checked, converted argument will be added to the
12080	/// end of these vectors.
12081	SmallVector<TemplateArgument, `4`> SugaredConverted, CanonicalConverted;
12082
12083	/// The check is being performed in the context of partial ordering.
12084	bool PartialOrdering;
12085
12086	/// If true, assume these template arguments are
12087	/// the injected template arguments for a template template parameter.
12088	/// This will relax the requirement that all its possible uses are valid:
12089	/// TTP checking is loose, and assumes that invalid uses will be diagnosed
12090	/// during instantiation.
12091	bool MatchingTTP;
12092
12093	/// Is set to true when, in the context of TTP matching, a pack parameter
12094	/// matches non-pack arguments.
12095	bool StrictPackMatch = false;
12096	};
12097
12098	/// Check that the given template argument corresponds to the given
12099	/// template parameter.
12100	///
12101	/// \param Param The template parameter against which the argument will be
12102	/// checked.
12103	///
12104	/// \param Arg The template argument, which may be updated due to conversions.
12105	///
12106	/// \param Template The template in which the template argument resides.
12107	///
12108	/// \param TemplateLoc The location of the template name for the template
12109	/// whose argument list we're matching.
12110	///
12111	/// \param RAngleLoc The location of the right angle bracket ('>') that closes
12112	/// the template argument list.
12113	///
12114	/// \param ArgumentPackIndex The index into the argument pack where this
12115	/// argument will be placed. Only valid if the parameter is a parameter pack.
12116	///
12117	/// \param CTAK Describes how we arrived at this particular template argument:
12118	/// explicitly written, deduced, etc.
12119	///
12120	/// \returns true on error, false otherwise.
12121	bool CheckTemplateArgument(NamedDecl *Param, TemplateArgumentLoc &Arg,
12122	NamedDecl *Template, SourceLocation TemplateLoc,
12123	SourceLocation RAngleLoc,
12124	unsigned ArgumentPackIndex,
12125	CheckTemplateArgumentInfo &CTAI,
12126	CheckTemplateArgumentKind CTAK);
12127
12128	/// Check that the given template arguments can be provided to
12129	/// the given template, converting the arguments along the way.
12130	///
12131	/// \param Template The template to which the template arguments are being
12132	/// provided.
12133	///
12134	/// \param TemplateLoc The location of the template name in the source.
12135	///
12136	/// \param TemplateArgs The list of template arguments. If the template is
12137	/// a template template parameter, this function may extend the set of
12138	/// template arguments to also include substituted, defaulted template
12139	/// arguments.
12140	///
12141	/// \param PartialTemplateArgs True if the list of template arguments is
12142	/// intentionally partial, e.g., because we're checking just the initial
12143	/// set of template arguments.
12144	///
12145	/// \param Converted Will receive the converted, canonicalized template
12146	/// arguments.
12147	///
12148	/// \param UpdateArgsWithConversions If \c true, update \p TemplateArgs to
12149	/// contain the converted forms of the template arguments as written.
12150	/// Otherwise, \p TemplateArgs will not be modified.
12151	///
12152	/// \param ConstraintsNotSatisfied If provided, and an error occurred, will
12153	/// receive true if the cause for the error is the associated constraints of
12154	/// the template not being satisfied by the template arguments.
12155	///
12156	/// \param DefaultArgs any default arguments from template specialization
12157	/// deduction.
12158	///
12159	/// \returns true if an error occurred, false otherwise.
12160	bool CheckTemplateArgumentList(TemplateDecl *Template,
12161	SourceLocation TemplateLoc,
12162	TemplateArgumentListInfo &TemplateArgs,
12163	const DefaultArguments &DefaultArgs,
12164	bool PartialTemplateArgs,
12165	CheckTemplateArgumentInfo &CTAI,
12166	bool UpdateArgsWithConversions = true,
12167	bool ConstraintsNotSatisfied = nullptr*);
12168
12169	bool CheckTemplateArgumentList(
12170	TemplateDecl Template, TemplateParameterList Params,
12171	SourceLocation TemplateLoc, TemplateArgumentListInfo &TemplateArgs,
12172	const DefaultArguments &DefaultArgs, bool PartialTemplateArgs,
12173	CheckTemplateArgumentInfo &CTAI, bool UpdateArgsWithConversions = true,
12174	bool ConstraintsNotSatisfied = nullptr*);
12175
12176	bool CheckTemplateTypeArgument(
12177	TemplateTypeParmDecl *Param, TemplateArgumentLoc &Arg,
12178	SmallVectorImpl<TemplateArgument> &SugaredConverted,
12179	SmallVectorImpl<TemplateArgument> &CanonicalConverted);
12180
12181	/// Check a template argument against its corresponding
12182	/// template type parameter.
12183	///
12184	/// This routine implements the semantics of C++ [temp.arg.type]. It
12185	/// returns true if an error occurred, and false otherwise.
12186	bool CheckTemplateArgument(TypeSourceInfo *Arg);
12187
12188	/// Check a template argument against its corresponding
12189	/// non-type template parameter.
12190	///
12191	/// This routine implements the semantics of C++ [temp.arg.nontype].
12192	/// If an error occurred, it returns ExprError(); otherwise, it
12193	/// returns the converted template argument. \p ParamType is the
12194	/// type of the non-type template parameter after it has been instantiated.
12195	ExprResult CheckTemplateArgument(NamedDecl *Param,
12196	QualType InstantiatedParamType, Expr *Arg,
12197	TemplateArgument &SugaredConverted,
12198	TemplateArgument &CanonicalConverted,
12199	bool StrictCheck,
12200	CheckTemplateArgumentKind CTAK);
12201
12202	/// Check a template argument against its corresponding
12203	/// template template parameter.
12204	///
12205	/// This routine implements the semantics of C++ [temp.arg.template].
12206	/// It returns true if an error occurred, and false otherwise.
12207	bool CheckTemplateTemplateArgument(TemplateTemplateParmDecl *Param,
12208	TemplateParameterList *Params,
12209	TemplateArgumentLoc &Arg,
12210	bool PartialOrdering,
12211	bool *StrictPackMatch);
12212
12213	bool CheckDeclCompatibleWithTemplateTemplate(TemplateDecl *Template,
12214	TemplateTemplateParmDecl *Param,
12215	const TemplateArgumentLoc &Arg);
12216
12217	void NoteTemplateLocation(const NamedDecl &Decl,
12218	std::optional<SourceRange> ParamRange = {});
12219	void NoteTemplateParameterLocation(const NamedDecl &Decl);
12220
12221	/// Given a non-type template argument that refers to a
12222	/// declaration and the type of its corresponding non-type template
12223	/// parameter, produce an expression that properly refers to that
12224	/// declaration.
12225	/// FIXME: This is used in some contexts where the resulting expression
12226	/// doesn't need to live too long. It would be useful if this function
12227	/// could return a temporary expression.
12228	ExprResult BuildExpressionFromDeclTemplateArgument(
12229	const TemplateArgument &Arg, QualType ParamType, SourceLocation Loc);
12230	ExprResult
12231	BuildExpressionFromNonTypeTemplateArgument(const TemplateArgument &Arg,
12232	SourceLocation Loc);
12233
12234	/// Enumeration describing how template parameter lists are compared
12235	/// for equality.
12236	enum TemplateParameterListEqualKind {
12237	/// We are matching the template parameter lists of two templates
12238	/// that might be redeclarations.
12239	///
12240	/// \code
12241	/// template<typename T> struct X;
12242	/// template<typename T> struct X;
12243	/// \endcode
12244	TPL_TemplateMatch,
12245
12246	/// We are matching the template parameter lists of two template
12247	/// template parameters as part of matching the template parameter lists
12248	/// of two templates that might be redeclarations.
12249	///
12250	/// \code
12251	/// template<template<int I> class TT> struct X;
12252	/// template<template<int Value> class Other> struct X;
12253	/// \endcode
12254	TPL_TemplateTemplateParmMatch,
12255
12256	/// We are determining whether the template-parameters are equivalent
12257	/// according to C++ [temp.over.link]/6. This comparison does not consider
12258	/// constraints.
12259	///
12260	/// \code
12261	/// template<C1 T> void f(T);
12262	/// template<C2 T> void f(T);
12263	/// \endcode
12264	TPL_TemplateParamsEquivalent,
12265	};
12266
12267	// A struct to represent the 'new' declaration, which is either itself just
12268	// the named decl, or the important information we need about it in order to
12269	// do constraint comparisons.
12270	class TemplateCompareNewDeclInfo {
12271	const NamedDecl ND = nullptr*;
12272	const DeclContext DC = nullptr*;
12273	const DeclContext LexicalDC = nullptr*;
12274	SourceLocation Loc;
12275
12276	public:
12277	TemplateCompareNewDeclInfo(const NamedDecl *ND) : ND(ND) {}
12278	TemplateCompareNewDeclInfo(const DeclContext *DeclCtx,
12279	const DeclContext *LexicalDeclCtx,
12280	SourceLocation Loc)
12281
12282	: DC(DeclCtx), LexicalDC(LexicalDeclCtx), Loc (Loc) {
12283	assert(DC && LexicalDC &&
12284	"Constructor only for cases where we have the information to put "
12285	"in here");
12286	}
12287
12288	// If this was constructed with no information, we cannot do substitution
12289	// for constraint comparison, so make sure we can check that.
12290	bool isInvalid() const { return !ND && !DC; }
12291
12292	const NamedDecl getDecl() const* { return ND; }
12293
12294	bool ContainsDecl(const NamedDecl ND) const* { return this->ND == ND; }
12295
12296	const DeclContext getLexicalDeclContext() const* {
12297	return ND ? ND->getLexicalDeclContext() : LexicalDC;
12298	}
12299
12300	const DeclContext getDeclContext() const* {
12301	return ND ? ND->getDeclContext() : DC;
12302	}
12303
12304	SourceLocation getLocation() const { return ND ? ND->getLocation() : Loc; }
12305	};
12306
12307	/// Determine whether the given template parameter lists are
12308	/// equivalent.
12309	///
12310	/// \param New The new template parameter list, typically written in the
12311	/// source code as part of a new template declaration.
12312	///
12313	/// \param Old The old template parameter list, typically found via
12314	/// name lookup of the template declared with this template parameter
12315	/// list.
12316	///
12317	/// \param Complain If true, this routine will produce a diagnostic if
12318	/// the template parameter lists are not equivalent.
12319	///
12320	/// \param Kind describes how we are to match the template parameter lists.
12321	///
12322	/// \param TemplateArgLoc If this source location is valid, then we
12323	/// are actually checking the template parameter list of a template
12324	/// argument (New) against the template parameter list of its
12325	/// corresponding template template parameter (Old). We produce
12326	/// slightly different diagnostics in this scenario.
12327	///
12328	/// \returns True if the template parameter lists are equal, false
12329	/// otherwise.
12330	bool TemplateParameterListsAreEqual(
12331	const TemplateCompareNewDeclInfo &NewInstFrom, TemplateParameterList *New,
12332	const NamedDecl OldInstFrom, TemplateParameterList Old, bool Complain,
12333	TemplateParameterListEqualKind Kind,
12334	SourceLocation TemplateArgLoc = SourceLocation ());
12335
12336	bool TemplateParameterListsAreEqual(
12337	TemplateParameterList New, TemplateParameterList Old, bool Complain,
12338	TemplateParameterListEqualKind Kind,
12339	SourceLocation TemplateArgLoc = SourceLocation ()) {
12340	return TemplateParameterListsAreEqual(NewInstFrom: nullptr, New, OldInstFrom: nullptr, Old, Complain,
12341	Kind, TemplateArgLoc);
12342	}
12343
12344	/// Check whether a template can be declared within this scope.
12345	///
12346	/// If the template declaration is valid in this scope, returns
12347	/// false. Otherwise, issues a diagnostic and returns true.
12348	bool CheckTemplateDeclScope(Scope S, TemplateParameterList TemplateParams);
12349
12350	/// Called when the parser has parsed a C++ typename
12351	/// specifier, e.g., "typename T::type".
12352	///
12353	/// \param S The scope in which this typename type occurs.
12354	/// \param TypenameLoc the location of the 'typename' keyword
12355	/// \param SS the nested-name-specifier following the typename (e.g., 'T::').
12356	/// \param II the identifier we're retrieving (e.g., 'type' in the example).
12357	/// \param IdLoc the location of the identifier.
12358	/// \param IsImplicitTypename context where T::type refers to a type.
12359	TypeResult ActOnTypenameType(
12360	Scope S, SourceLocation TypenameLoc, const* CXXScopeSpec &SS,
12361	const IdentifierInfo &II, SourceLocation IdLoc,
12362	ImplicitTypenameContext IsImplicitTypename = ImplicitTypenameContext::No);
12363
12364	/// Called when the parser has parsed a C++ typename
12365	/// specifier that ends in a template-id, e.g.,
12366	/// "typename MetaFun::template apply<T1, T2>".
12367	///
12368	/// \param S The scope in which this typename type occurs.
12369	/// \param TypenameLoc the location of the 'typename' keyword
12370	/// \param SS the nested-name-specifier following the typename (e.g., 'T::').
12371	/// \param TemplateLoc the location of the 'template' keyword, if any.
12372	/// \param TemplateName The template name.
12373	/// \param TemplateII The identifier used to name the template.
12374	/// \param TemplateIILoc The location of the template name.
12375	/// \param LAngleLoc The location of the opening angle bracket ('<').
12376	/// \param TemplateArgs The template arguments.
12377	/// \param RAngleLoc The location of the closing angle bracket ('>').
12378	TypeResult
12379	ActOnTypenameType(Scope *S, SourceLocation TypenameLoc,
12380	const CXXScopeSpec &SS, SourceLocation TemplateLoc,
12381	TemplateTy TemplateName, const IdentifierInfo *TemplateII,
12382	SourceLocation TemplateIILoc, SourceLocation LAngleLoc,
12383	ASTTemplateArgsPtr TemplateArgs, SourceLocation RAngleLoc);
12384
12385	QualType CheckTypenameType(ElaboratedTypeKeyword Keyword,
12386	SourceLocation KeywordLoc,
12387	NestedNameSpecifierLoc QualifierLoc,
12388	const IdentifierInfo &II, SourceLocation IILoc,
12389	TypeSourceInfo *TSI, bool* DeducedTSTContext);
12390
12391	QualType CheckTypenameType(ElaboratedTypeKeyword Keyword,
12392	SourceLocation KeywordLoc,
12393	NestedNameSpecifierLoc QualifierLoc,
12394	const IdentifierInfo &II, SourceLocation IILoc,
12395	bool DeducedTSTContext = true);
12396
12397	/// Rebuilds a type within the context of the current instantiation.
12398	///
12399	/// The type \p T is part of the type of an out-of-line member definition of
12400	/// a class template (or class template partial specialization) that was
12401	/// parsed and constructed before we entered the scope of the class template
12402	/// (or partial specialization thereof). This routine will rebuild that type
12403	/// now that we have entered the declarator's scope, which may produce
12404	/// different canonical types, e.g.,
12405	///
12406	/// \code
12407	/// template<typename T>
12408	/// struct X {
12409	/// typedef T pointer;*
12410	/// pointer data();
12411	/// };
12412	///
12413	/// template<typename T>
12414	/// typename X<T>::pointer X<T>::data() { ... }
12415	/// \endcode
12416	///
12417	/// Here, the type "typename X<T>::pointer" will be created as a
12418	/// DependentNameType, since we do not know that we can look into X<T> when we
12419	/// parsed the type. This function will rebuild the type, performing the
12420	/// lookup of "pointer" in X<T> and returning an ElaboratedType whose
12421	/// canonical type is the same as the canonical type of T, allowing the*
12422	/// return types of the out-of-line definition and the declaration to match.
12423	TypeSourceInfo RebuildTypeInCurrentInstantiation(TypeSourceInfo T,
12424	SourceLocation Loc,
12425	DeclarationName Name);
12426	bool RebuildNestedNameSpecifierInCurrentInstantiation(CXXScopeSpec &SS);
12427
12428	ExprResult RebuildExprInCurrentInstantiation(Expr *E);
12429
12430	/// Rebuild the template parameters now that we know we're in a current
12431	/// instantiation.
12432	bool
12433	RebuildTemplateParamsInCurrentInstantiation(TemplateParameterList *Params);
12434
12435	/// Produces a formatted string that describes the binding of
12436	/// template parameters to template arguments.
12437	std::string
12438	getTemplateArgumentBindingsText(const TemplateParameterList *Params,
12439	const TemplateArgumentList &Args);
12440
12441	std::string
12442	getTemplateArgumentBindingsText(const TemplateParameterList *Params,
12443	const TemplateArgument *Args,
12444	unsigned NumArgs);
12445
12446	void diagnoseExprIntendedAsTemplateName(Scope *S, ExprResult TemplateName,
12447	SourceLocation Less,
12448	SourceLocation Greater);
12449
12450	/// ActOnDependentIdExpression - Handle a dependent id-expression that
12451	/// was just parsed. This is only possible with an explicit scope
12452	/// specifier naming a dependent type.
12453	ExprResult ActOnDependentIdExpression(
12454	const CXXScopeSpec &SS, SourceLocation TemplateKWLoc,
12455	const DeclarationNameInfo &NameInfo, bool isAddressOfOperand,
12456	const TemplateArgumentListInfo *TemplateArgs);
12457
12458	ExprResult
12459	BuildDependentDeclRefExpr(const CXXScopeSpec &SS,
12460	SourceLocation TemplateKWLoc,
12461	const DeclarationNameInfo &NameInfo,
12462	const TemplateArgumentListInfo *TemplateArgs);
12463
12464	// Calculates whether the expression Constraint depends on an enclosing
12465	// template, for the purposes of [temp.friend] p9.
12466	// TemplateDepth is the 'depth' of the friend function, which is used to
12467	// compare whether a declaration reference is referring to a containing
12468	// template, or just the current friend function. A 'lower' TemplateDepth in
12469	// the AST refers to a 'containing' template. As the constraint is
12470	// uninstantiated, this is relative to the 'top' of the TU.
12471	bool
12472	ConstraintExpressionDependsOnEnclosingTemplate(const FunctionDecl *Friend,
12473	unsigned TemplateDepth,
12474	const Expr *Constraint);
12475
12476	/// Find the failed Boolean condition within a given Boolean
12477	/// constant expression, and describe it with a string.
12478	std::pair<Expr , std::string> findFailedBooleanCondition(Expr Cond);
12479
12480	void CheckDeductionGuideTemplate(FunctionTemplateDecl *TD);
12481
12482	ConceptDecl *ActOnStartConceptDefinition(
12483	Scope *S, MultiTemplateParamsArg TemplateParameterLists,
12484	const IdentifierInfo *Name, SourceLocation NameLoc);
12485
12486	ConceptDecl ActOnFinishConceptDefinition(Scope S, ConceptDecl *C,
12487	Expr *ConstraintExpr,
12488	const ParsedAttributesView &Attrs);
12489
12490	void CheckConceptRedefinition(ConceptDecl *NewDecl, LookupResult &Previous,
12491	bool &AddToScope);
12492	bool CheckConceptUseInDefinition(NamedDecl *Concept, SourceLocation Loc);
12493
12494	TypeResult ActOnDependentTag(Scope S, unsigned* TagSpec, TagUseKind TUK,
12495	const CXXScopeSpec &SS,
12496	const IdentifierInfo *Name,
12497	SourceLocation TagLoc, SourceLocation NameLoc);
12498
12499	void MarkAsLateParsedTemplate(FunctionDecl FD, Decl FnD,
12500	CachedTokens &Toks);
12501	void UnmarkAsLateParsedTemplate(FunctionDecl *FD);
12502	bool IsInsideALocalClassWithinATemplateFunction();
12503
12504	/// We've found a use of a templated declaration that would trigger an
12505	/// implicit instantiation. Check that any relevant explicit specializations
12506	/// and partial specializations are visible/reachable, and diagnose if not.
12507	void checkSpecializationVisibility(SourceLocation Loc, NamedDecl *Spec);
12508	void checkSpecializationReachability(SourceLocation Loc, NamedDecl *Spec);
12509
12510	///@}
12511
12512	//
12513	//
12514	// -------------------------------------------------------------------------
12515	//
12516	//
12517
12518	/// \name C++ Template Argument Deduction
12519	/// Implementations are in SemaTemplateDeduction.cpp
12520	///@{
12521
12522	public:
12523	class SFINAETrap;
12524
12525	struct SFINAEContextBase {
12526	SFINAEContextBase(Sema &S, SFINAETrap *Cur)
12527	: S(S), Prev(std::exchange(obj&: S.CurrentSFINAEContext, new_val&: Cur)) {}
12528
12529	protected:
12530	Sema &S;
12531	~SFINAEContextBase() { S.CurrentSFINAEContext = Prev; }
12532	SFINAEContextBase(const SFINAEContextBase &) = delete;
12533	SFINAEContextBase &operator=(const SFINAEContextBase &) = delete;
12534
12535	private:
12536	SFINAETrap *Prev;
12537	};
12538
12539	struct NonSFINAEContext : SFINAEContextBase {
12540	NonSFINAEContext(Sema &S) : SFINAEContextBase (S, nullptr) {}
12541	};
12542
12543	/// RAII class used to determine whether SFINAE has
12544	/// trapped any errors that occur during template argument
12545	/// deduction.
12546	class SFINAETrap : SFINAEContextBase {
12547	bool HasErrorOcurred = false;
12548	bool WithAccessChecking = false;
12549	bool PrevLastDiagnosticIgnored =
12550	S.getDiagnostics().isLastDiagnosticIgnored();
12551	sema::TemplateDeductionInfo DeductionInfo = nullptr*;
12552
12553	SFINAETrap(Sema &S, sema::TemplateDeductionInfo *Info,
12554	bool WithAccessChecking)
12555	: SFINAEContextBase (S, this), WithAccessChecking(WithAccessChecking),
12556	DeductionInfo(Info) {}
12557
12558	public:
12559	/// \param WithAccessChecking If true, discard all diagnostics (from the
12560	/// immediate context) instead of adding them to the currently active
12561	/// \ref TemplateDeductionInfo.
12562	explicit SFINAETrap(Sema &S, bool WithAccessChecking = false)
12563	: SFINAETrap (S, /Info=/nullptr, WithAccessChecking) {}
12564
12565	SFINAETrap(Sema &S, sema::TemplateDeductionInfo &Info)
12566	: SFINAETrap (S, &Info, /WithAccessChecking=/false) {}
12567
12568	~SFINAETrap() {
12569	S.getDiagnostics().setLastDiagnosticIgnored(PrevLastDiagnosticIgnored);
12570	}
12571
12572	SFINAETrap(const SFINAETrap &) = delete;
12573	SFINAETrap &operator=(const SFINAETrap &) = delete;
12574
12575	sema::TemplateDeductionInfo getDeductionInfo() const* {
12576	return DeductionInfo;
12577	}
12578
12579	/// Determine whether any SFINAE errors have been trapped.
12580	bool hasErrorOccurred() const { return HasErrorOcurred; }
12581	void setErrorOccurred() { HasErrorOcurred = true; }
12582
12583	bool withAccessChecking() const { return WithAccessChecking; }
12584	};
12585
12586	/// RAII class used to indicate that we are performing provisional
12587	/// semantic analysis to determine the validity of a construct, so
12588	/// typo-correction and diagnostics in the immediate context (not within
12589	/// implicitly-instantiated templates) should be suppressed.
12590	class TentativeAnalysisScope {
12591	Sema &SemaRef;
12592	// FIXME: Using a SFINAETrap for this is a hack.
12593	SFINAETrap Trap;
12594	bool PrevDisableTypoCorrection;
12595
12596	public:
12597	explicit TentativeAnalysisScope(Sema &SemaRef)
12598	: SemaRef(SemaRef), Trap (SemaRef, /ForValidityCheck=/true),
12599	PrevDisableTypoCorrection(SemaRef.DisableTypoCorrection) {
12600	SemaRef.DisableTypoCorrection = true;
12601	}
12602	~TentativeAnalysisScope() {
12603	SemaRef.DisableTypoCorrection = PrevDisableTypoCorrection;
12604	}
12605
12606	TentativeAnalysisScope(const TentativeAnalysisScope &) = delete;
12607	TentativeAnalysisScope &operator=(const TentativeAnalysisScope &) = delete;
12608	};
12609
12610	/// For each declaration that involved template argument deduction, the
12611	/// set of diagnostics that were suppressed during that template argument
12612	/// deduction.
12613	///
12614	/// FIXME: Serialize this structure to the AST file.
12615	typedef llvm::DenseMap<Decl *, SmallVector<PartialDiagnosticAt, `1`>>
12616	SuppressedDiagnosticsMap;
12617	SuppressedDiagnosticsMap SuppressedDiagnostics;
12618
12619	/// Compare types for equality with respect to possibly compatible
12620	/// function types (noreturn adjustment, implicit calling conventions). If any
12621	/// of parameter and argument is not a function, just perform type comparison.
12622	///
12623	/// \param P the template parameter type.
12624	///
12625	/// \param A the argument type.
12626	bool isSameOrCompatibleFunctionType(QualType Param, QualType Arg);
12627
12628	/// Allocate a TemplateArgumentLoc where all locations have
12629	/// been initialized to the given location.
12630	///
12631	/// \param Arg The template argument we are producing template argument
12632	/// location information for.
12633	///
12634	/// \param NTTPType For a declaration template argument, the type of
12635	/// the non-type template parameter that corresponds to this template
12636	/// argument. Can be null if no type sugar is available to add to the
12637	/// type from the template argument.
12638	///
12639	/// \param Loc The source location to use for the resulting template
12640	/// argument.
12641	TemplateArgumentLoc getTrivialTemplateArgumentLoc(const TemplateArgument &Arg,
12642	QualType NTTPType,
12643	SourceLocation Loc);
12644
12645	/// Get a template argument mapping the given template parameter to itself,
12646	/// e.g. for X in \c template<int X>, this would return an expression template
12647	/// argument referencing X.
12648	TemplateArgumentLoc getIdentityTemplateArgumentLoc(NamedDecl *Param,
12649	SourceLocation Location);
12650
12651	/// Adjust the type \p ArgFunctionType to match the calling convention,
12652	/// noreturn, and optionally the exception specification of \p FunctionType.
12653	/// Deduction often wants to ignore these properties when matching function
12654	/// types.
12655	QualType adjustCCAndNoReturn(QualType ArgFunctionType, QualType FunctionType,
12656	bool AdjustExceptionSpec = false);
12657
12658	TemplateDeductionResult
12659	DeduceTemplateArguments(ClassTemplatePartialSpecializationDecl *Partial,
12660	ArrayRef<TemplateArgument> TemplateArgs,
12661	sema::TemplateDeductionInfo &Info);
12662
12663	TemplateDeductionResult
12664	DeduceTemplateArguments(VarTemplatePartialSpecializationDecl *Partial,
12665	ArrayRef<TemplateArgument> TemplateArgs,
12666	sema::TemplateDeductionInfo &Info);
12667
12668	/// Deduce the template arguments of the given template from \p FromType.
12669	/// Used to implement the IsDeducible constraint for alias CTAD per C++
12670	/// [over.match.class.deduct]p4.
12671	///
12672	/// It only supports class or type alias templates.
12673	TemplateDeductionResult
12674	DeduceTemplateArgumentsFromType(TemplateDecl *TD, QualType FromType,
12675	sema::TemplateDeductionInfo &Info);
12676
12677	TemplateDeductionResult DeduceTemplateArguments(
12678	TemplateParameterList *TemplateParams, ArrayRef<TemplateArgument> Ps,
12679	ArrayRef<TemplateArgument> As, sema::TemplateDeductionInfo &Info,
12680	SmallVectorImpl<DeducedTemplateArgument> &Deduced,
12681	bool NumberOfArgumentsMustMatch);
12682
12683	/// Substitute the explicitly-provided template arguments into the
12684	/// given function template according to C++ [temp.arg.explicit].
12685	///
12686	/// \param FunctionTemplate the function template into which the explicit
12687	/// template arguments will be substituted.
12688	///
12689	/// \param ExplicitTemplateArgs the explicitly-specified template
12690	/// arguments.
12691	///
12692	/// \param Deduced the deduced template arguments, which will be populated
12693	/// with the converted and checked explicit template arguments.
12694	///
12695	/// \param ParamTypes will be populated with the instantiated function
12696	/// parameters.
12697	///
12698	/// \param FunctionType if non-NULL, the result type of the function template
12699	/// will also be instantiated and the pointed-to value will be updated with
12700	/// the instantiated function type.
12701	///
12702	/// \param Info if substitution fails for any reason, this object will be
12703	/// populated with more information about the failure.
12704	///
12705	/// \returns TemplateDeductionResult::Success if substitution was successful,
12706	/// or some failure condition.
12707	TemplateDeductionResult SubstituteExplicitTemplateArguments(
12708	FunctionTemplateDecl *FunctionTemplate,
12709	TemplateArgumentListInfo &ExplicitTemplateArgs,
12710	SmallVectorImpl<DeducedTemplateArgument> &Deduced,
12711	SmallVectorImpl<QualType> &ParamTypes, QualType *FunctionType,
12712	sema::TemplateDeductionInfo &Info);
12713
12714	/// brief A function argument from which we performed template argument
12715	// deduction for a call.
12716	struct OriginalCallArg {
12717	OriginalCallArg(QualType OriginalParamType, bool DecomposedParam,
12718	unsigned ArgIdx, QualType OriginalArgType)
12719	: OriginalParamType (OriginalParamType),
12720	DecomposedParam(DecomposedParam), ArgIdx(ArgIdx),
12721	OriginalArgType (OriginalArgType) {}
12722
12723	QualType OriginalParamType;
12724	bool DecomposedParam;
12725	unsigned ArgIdx;
12726	QualType OriginalArgType;
12727	};
12728
12729	/// Finish template argument deduction for a function template,
12730	/// checking the deduced template arguments for completeness and forming
12731	/// the function template specialization.
12732	///
12733	/// \param OriginalCallArgs If non-NULL, the original call arguments against
12734	/// which the deduced argument types should be compared.
12735	/// \param CheckNonDependent Callback before substituting into the declaration
12736	/// with the deduced template arguments.
12737	/// \param OnlyInitializeNonUserDefinedConversions is used as a workaround for
12738	/// some breakages introduced by CWG2369, where non-user-defined conversions
12739	/// are checked first before the constraints.
12740	TemplateDeductionResult FinishTemplateArgumentDeduction(
12741	FunctionTemplateDecl *FunctionTemplate,
12742	SmallVectorImpl<DeducedTemplateArgument> &Deduced,
12743	unsigned NumExplicitlySpecified, FunctionDecl *&Specialization,
12744	sema::TemplateDeductionInfo &Info,
12745	SmallVectorImpl<OriginalCallArg> const *OriginalCallArgs,
12746	bool PartialOverloading, bool PartialOrdering,
12747	bool ForOverloadSetAddressResolution,
12748	llvm::function_ref<bool(bool)> CheckNonDependent =
12749	[](bool /OnlyInitializeNonUserDefinedConversions/) {
12750	return false;
12751	});
12752
12753	/// Perform [temp.friend] p5 template argument deduction for a dependent
12754	/// friend declaration and a candidate class template specialization.
12755	bool DeduceTemplateArguments(FriendTemplateDecl *FTD,
12756	ClassTemplateDecl *PatternCTD,
12757	ClassTemplateDecl *CandidateCTD,
12758	ArrayRef<TemplateParameterList *> TPLs,
12759	ArrayRef<TemplateArgument> PatternArgs,
12760	ArrayRef<TemplateArgument> CandidateArgs,
12761	SourceLocation Loc,
12762	TemplateSpecCandidateSet *FailedTSC,
12763	MultiLevelTemplateArgumentList &DeducedArgs);
12764
12765	/// Perform template argument deduction from a function call
12766	/// (C++ [temp.deduct.call]).
12767	///
12768	/// \param FunctionTemplate the function template for which we are performing
12769	/// template argument deduction.
12770	///
12771	/// \param ExplicitTemplateArgs the explicit template arguments provided
12772	/// for this call.
12773	///
12774	/// \param Args the function call arguments
12775	///
12776	/// \param Specialization if template argument deduction was successful,
12777	/// this will be set to the function template specialization produced by
12778	/// template argument deduction.
12779	///
12780	/// \param Info the argument will be updated to provide additional information
12781	/// about template argument deduction.
12782	///
12783	/// \param CheckNonDependent A callback to invoke to check conversions for
12784	/// non-dependent parameters, between deduction and substitution, per DR1391.
12785	/// If this returns true, substitution will be skipped and we return
12786	/// TemplateDeductionResult::NonDependentConversionFailure. The callback is
12787	/// passed the parameter types (after substituting explicit template
12788	/// arguments).
12789	///
12790	/// \returns the result of template argument deduction.
12791	TemplateDeductionResult DeduceTemplateArguments(
12792	FunctionTemplateDecl *FunctionTemplate,
12793	TemplateArgumentListInfo ExplicitTemplateArgs, ArrayRef<Expr > Args,
12794	FunctionDecl *&Specialization, sema::TemplateDeductionInfo &Info,
12795	bool PartialOverloading, bool AggregateDeductionCandidate,
12796	bool PartialOrdering, QualType ObjectType,
12797	Expr::Classification ObjectClassification,
12798	bool ForOverloadSetAddressResolution,
12799	llvm::function_ref<bool(ArrayRef<QualType>, bool)> CheckNonDependent);
12800
12801	/// Deduce template arguments when taking the address of a function
12802	/// template (C++ [temp.deduct.funcaddr]) or matching a specialization to
12803	/// a template.
12804	///
12805	/// \param FunctionTemplate the function template for which we are performing
12806	/// template argument deduction.
12807	///
12808	/// \param ExplicitTemplateArgs the explicitly-specified template
12809	/// arguments.
12810	///
12811	/// \param ArgFunctionType the function type that will be used as the
12812	/// "argument" type (A) when performing template argument deduction from the
12813	/// function template's function type. This type may be NULL, if there is no
12814	/// argument type to compare against, in C++0x [temp.arg.explicit]p3.
12815	///
12816	/// \param Specialization if template argument deduction was successful,
12817	/// this will be set to the function template specialization produced by
12818	/// template argument deduction.
12819	///
12820	/// \param Info the argument will be updated to provide additional information
12821	/// about template argument deduction.
12822	///
12823	/// \param IsAddressOfFunction If \c true, we are deducing as part of taking
12824	/// the address of a function template per [temp.deduct.funcaddr] and
12825	/// [over.over]. If \c false, we are looking up a function template
12826	/// specialization based on its signature, per [temp.deduct.decl].
12827	///
12828	/// \returns the result of template argument deduction.
12829	TemplateDeductionResult DeduceTemplateArguments(
12830	FunctionTemplateDecl *FunctionTemplate,
12831	TemplateArgumentListInfo *ExplicitTemplateArgs, QualType ArgFunctionType,
12832	FunctionDecl *&Specialization, sema::TemplateDeductionInfo &Info,
12833	bool IsAddressOfFunction = false);
12834
12835	/// Deduce template arguments for a templated conversion
12836	/// function (C++ [temp.deduct.conv]) and, if successful, produce a
12837	/// conversion function template specialization.
12838	TemplateDeductionResult DeduceTemplateArguments(
12839	FunctionTemplateDecl *FunctionTemplate, QualType ObjectType,
12840	Expr::Classification ObjectClassification, QualType ToType,
12841	CXXConversionDecl *&Specialization, sema::TemplateDeductionInfo &Info);
12842
12843	/// Deduce template arguments for a function template when there is
12844	/// nothing to deduce against (C++0x [temp.arg.explicit]p3).
12845	///
12846	/// \param FunctionTemplate the function template for which we are performing
12847	/// template argument deduction.
12848	///
12849	/// \param ExplicitTemplateArgs the explicitly-specified template
12850	/// arguments.
12851	///
12852	/// \param Specialization if template argument deduction was successful,
12853	/// this will be set to the function template specialization produced by
12854	/// template argument deduction.
12855	///
12856	/// \param Info the argument will be updated to provide additional information
12857	/// about template argument deduction.
12858	///
12859	/// \param IsAddressOfFunction If \c true, we are deducing as part of taking
12860	/// the address of a function template in a context where we do not have a
12861	/// target type, per [over.over]. If \c false, we are looking up a function
12862	/// template specialization based on its signature, which only happens when
12863	/// deducing a function parameter type from an argument that is a template-id
12864	/// naming a function template specialization.
12865	///
12866	/// \returns the result of template argument deduction.
12867	TemplateDeductionResult
12868	DeduceTemplateArguments(FunctionTemplateDecl *FunctionTemplate,
12869	TemplateArgumentListInfo *ExplicitTemplateArgs,
12870	FunctionDecl *&Specialization,
12871	sema::TemplateDeductionInfo &Info,
12872	bool IsAddressOfFunction = false);
12873
12874	/// Substitute Replacement for \p auto in \p TypeWithAuto
12875	QualType SubstAutoType(QualType TypeWithAuto, QualType Replacement);
12876	/// Substitute Replacement for auto in TypeWithAuto
12877	TypeSourceInfo SubstAutoTypeSourceInfo(TypeSourceInfo TypeWithAuto,
12878	QualType Replacement);
12879
12880	// Substitute auto in TypeWithAuto for a Dependent auto type
12881	QualType SubstAutoTypeDependent(QualType TypeWithAuto);
12882
12883	// Substitute auto in TypeWithAuto for a Dependent auto type
12884	TypeSourceInfo *
12885	SubstAutoTypeSourceInfoDependent(TypeSourceInfo *TypeWithAuto);
12886
12887	/// Completely replace the \c auto in \p TypeWithAuto by
12888	/// \p Replacement. This does not retain any \c auto type sugar.
12889	QualType ReplaceAutoType(QualType TypeWithAuto, QualType Replacement);
12890	TypeSourceInfo ReplaceAutoTypeSourceInfo(TypeSourceInfo TypeWithAuto,
12891	QualType Replacement);
12892
12893	/// Deduce the type for an auto type-specifier (C++11 [dcl.spec.auto]p6)
12894	///
12895	/// Note that this is done even if the initializer is dependent. (This is
12896	/// necessary to support partial ordering of templates using 'auto'.)
12897	/// A dependent type will be produced when deducing from a dependent type.
12898	///
12899	/// \param Type the type pattern using the auto type-specifier.
12900	/// \param Init the initializer for the variable whose type is to be deduced.
12901	/// \param Result if type deduction was successful, this will be set to the
12902	/// deduced type.
12903	/// \param Info the argument will be updated to provide additional information
12904	/// about template argument deduction.
12905	/// \param DependentDeduction Set if we should permit deduction in
12906	/// dependent cases. This is necessary for template partial ordering
12907	/// with 'auto' template parameters. The template parameter depth to be
12908	/// used should be specified in the 'Info' parameter.
12909	/// \param IgnoreConstraints Set if we should not fail if the deduced type
12910	/// does not satisfy the type-constraint in the auto
12911	/// type.
12912	TemplateDeductionResult
12913	DeduceAutoType(TypeLoc AutoTypeLoc, Expr *Initializer, QualType &Result,
12914	sema::TemplateDeductionInfo &Info,
12915	bool DependentDeduction = false,
12916	bool IgnoreConstraints = false,
12917	TemplateSpecCandidateSet FailedTSC = nullptr*);
12918	void DiagnoseAutoDeductionFailure(const VarDecl VDecl, const* Expr *Init);
12919	bool DeduceReturnType(FunctionDecl *FD, SourceLocation Loc,
12920	bool Diagnose = true);
12921
12922	bool CheckIfFunctionSpecializationIsImmediate(FunctionDecl *FD,
12923	SourceLocation Loc);
12924
12925	/// Returns the more specialized class template partial specialization
12926	/// according to the rules of partial ordering of class template partial
12927	/// specializations (C++ [temp.class.order]).
12928	///
12929	/// \param PS1 the first class template partial specialization
12930	///
12931	/// \param PS2 the second class template partial specialization
12932	///
12933	/// \returns the more specialized class template partial specialization. If
12934	/// neither partial specialization is more specialized, returns NULL.
12935	ClassTemplatePartialSpecializationDecl *
12936	getMoreSpecializedPartialSpecialization(
12937	ClassTemplatePartialSpecializationDecl *PS1,
12938	ClassTemplatePartialSpecializationDecl *PS2, SourceLocation Loc);
12939
12940	bool isMoreSpecializedThanPrimary(ClassTemplatePartialSpecializationDecl *T,
12941	sema::TemplateDeductionInfo &Info);
12942
12943	VarTemplatePartialSpecializationDecl *getMoreSpecializedPartialSpecialization(
12944	VarTemplatePartialSpecializationDecl *PS1,
12945	VarTemplatePartialSpecializationDecl *PS2, SourceLocation Loc);
12946
12947	bool isMoreSpecializedThanPrimary(VarTemplatePartialSpecializationDecl *T,
12948	sema::TemplateDeductionInfo &Info);
12949
12950	bool isTemplateTemplateParameterAtLeastAsSpecializedAs(
12951	TemplateParameterList PParam, TemplateDecl PArg, TemplateDecl *AArg,
12952	const DefaultArguments &DefaultArgs, SourceLocation ArgLoc,
12953	bool PartialOrdering, bool *StrictPackMatch);
12954
12955	/// Mark which template parameters are used in a given expression.
12956	///
12957	/// \param E the expression from which template parameters will be deduced.
12958	///
12959	/// \param Used a bit vector whose elements will be set to \c true
12960	/// to indicate when the corresponding template parameter will be
12961	/// deduced.
12962	void MarkUsedTemplateParameters(const Expr E, bool* OnlyDeduced,
12963	unsigned Depth, llvm::SmallBitVector &Used);
12964
12965	/// Mark which template parameters are named in a given expression.
12966	///
12967	/// Unlike MarkUsedTemplateParameters, this excludes parameter that
12968	/// are used but not directly named by an expression - i.e. it excludes
12969	/// any template parameter that denotes the type of a referenced NTTP.
12970	///
12971	/// \param Used a bit vector whose elements will be set to \c true
12972	/// to indicate when the corresponding template parameter will be
12973	/// deduced.
12974	void MarkUsedTemplateParametersForSubsumptionParameterMapping(
12975	const Expr E, unsigned* Depth, llvm::SmallBitVector &Used);
12976
12977	/// Mark which template parameters can be deduced from a given
12978	/// template argument list.
12979	///
12980	/// \param TemplateArgs the template argument list from which template
12981	/// parameters will be deduced.
12982	///
12983	/// \param Used a bit vector whose elements will be set to \c true
12984	/// to indicate when the corresponding template parameter will be
12985	/// deduced.
12986	void MarkUsedTemplateParameters(const TemplateArgumentList &TemplateArgs,
12987	bool OnlyDeduced, unsigned Depth,
12988	llvm::SmallBitVector &Used);
12989
12990	void MarkUsedTemplateParameters(ArrayRef<TemplateArgument> TemplateArgs,
12991	bool OnlyDeduced, unsigned Depth,
12992	llvm::SmallBitVector &Used);
12993
12994	void MarkUsedTemplateParameters(ArrayRef<TemplateArgumentLoc> TemplateArgs,
12995	unsigned Depth, llvm::SmallBitVector &Used);
12996
12997	void
12998	MarkDeducedTemplateParameters(const FunctionTemplateDecl *FunctionTemplate,
12999	llvm::SmallBitVector &Deduced) {
13000	return MarkDeducedTemplateParameters(Ctx&: Context, FunctionTemplate, Deduced);
13001	}
13002
13003	/// Marks all of the template parameters that will be deduced by a
13004	/// call to the given function template.
13005	static void
13006	MarkDeducedTemplateParameters(ASTContext &Ctx,
13007	const FunctionTemplateDecl *FunctionTemplate,
13008	llvm::SmallBitVector &Deduced);
13009
13010	/// Returns the more specialized function template according
13011	/// to the rules of function template partial ordering (C++
13012	/// [temp.func.order]).
13013	///
13014	/// \param FT1 the first function template
13015	///
13016	/// \param FT2 the second function template
13017	///
13018	/// \param TPOC the context in which we are performing partial ordering of
13019	/// function templates.
13020	///
13021	/// \param NumCallArguments1 The number of arguments in the call to FT1, used
13022	/// only when \c TPOC is \c TPOC_Call. Does not include the object argument
13023	/// when calling a member function.
13024	///
13025	/// \param RawObj1Ty The type of the object parameter of FT1 if a member
13026	/// function only used if \c TPOC is \c TPOC_Call and FT1 is a Function
13027	/// template from a member function
13028	///
13029	/// \param RawObj2Ty The type of the object parameter of FT2 if a member
13030	/// function only used if \c TPOC is \c TPOC_Call and FT2 is a Function
13031	/// template from a member function
13032	///
13033	/// \param Reversed If \c true, exactly one of FT1 and FT2 is an overload
13034	/// candidate with a reversed parameter order. In this case, the corresponding
13035	/// P/A pairs between FT1 and FT2 are reversed.
13036	///
13037	/// \returns the more specialized function template. If neither
13038	/// template is more specialized, returns NULL.
13039	FunctionTemplateDecl *getMoreSpecializedTemplate(
13040	FunctionTemplateDecl FT1, FunctionTemplateDecl FT2, SourceLocation Loc,
13041	TemplatePartialOrderingContext TPOC, unsigned NumCallArguments1,
13042	QualType RawObj1Ty = {}, QualType RawObj2Ty = {}, bool Reversed = false,
13043	bool PartialOverloading = false);
13044
13045	/// Retrieve the most specialized of the given function template
13046	/// specializations.
13047	///
13048	/// \param SpecBegin the start iterator of the function template
13049	/// specializations that we will be comparing.
13050	///
13051	/// \param SpecEnd the end iterator of the function template
13052	/// specializations, paired with \p SpecBegin.
13053	///
13054	/// \param Loc the location where the ambiguity or no-specializations
13055	/// diagnostic should occur.
13056	///
13057	/// \param NoneDiag partial diagnostic used to diagnose cases where there are
13058	/// no matching candidates.
13059	///
13060	/// \param AmbigDiag partial diagnostic used to diagnose an ambiguity, if one
13061	/// occurs.
13062	///
13063	/// \param CandidateDiag partial diagnostic used for each function template
13064	/// specialization that is a candidate in the ambiguous ordering. One
13065	/// parameter in this diagnostic should be unbound, which will correspond to
13066	/// the string describing the template arguments for the function template
13067	/// specialization.
13068	///
13069	/// \returns the most specialized function template specialization, if
13070	/// found. Otherwise, returns SpecEnd.
13071	UnresolvedSetIterator
13072	getMostSpecialized(UnresolvedSetIterator SBegin, UnresolvedSetIterator SEnd,
13073	TemplateSpecCandidateSet &FailedCandidates,
13074	SourceLocation Loc, const PartialDiagnostic &NoneDiag,
13075	const PartialDiagnostic &AmbigDiag,
13076	const PartialDiagnostic &CandidateDiag,
13077	bool Complain = true, QualType TargetType = QualType ());
13078
13079	/// Returns the more constrained function according to the rules of
13080	/// partial ordering by constraints (C++ [temp.constr.order]).
13081	///
13082	/// \param FD1 the first function
13083	///
13084	/// \param FD2 the second function
13085	///
13086	/// \returns the more constrained function. If neither function is
13087	/// more constrained, returns NULL.
13088	FunctionDecl getMoreConstrainedFunction(FunctionDecl FD1,
13089	FunctionDecl *FD2);
13090
13091	///@}
13092
13093	//
13094	//
13095	// -------------------------------------------------------------------------
13096	//
13097	//
13098
13099	/// \name C++ Template Deduction Guide
13100	/// Implementations are in SemaTemplateDeductionGuide.cpp
13101	///@{
13102
13103	/// Declare implicit deduction guides for a class template if we've
13104	/// not already done so.
13105	void DeclareImplicitDeductionGuides(TemplateDecl *Template,
13106	SourceLocation Loc);
13107
13108	CXXDeductionGuideDecl *DeclareAggregateDeductionGuideFromInitList(
13109	TemplateDecl *Template, MutableArrayRef<QualType> ParamTypes,
13110	SourceLocation Loc);
13111
13112	///@}
13113
13114	//
13115	//
13116	// -------------------------------------------------------------------------
13117	//
13118	//
13119
13120	/// \name C++ Template Instantiation
13121	/// Implementations are in SemaTemplateInstantiate.cpp
13122	///@{
13123
13124	public:
13125	/// A helper class for building up ExtParameterInfos.
13126	class ExtParameterInfoBuilder {
13127	SmallVector<FunctionProtoType::ExtParameterInfo, `16`> Infos;
13128	bool HasInteresting = false;
13129
13130	public:
13131	/// Set the ExtParameterInfo for the parameter at the given index,
13132	///
13133	void set(unsigned index, FunctionProtoType::ExtParameterInfo info) {
13134	assert(Infos.size() <= index);
13135	Infos.resize(N: index);
13136	Infos.push_back(Elt: info);
13137
13138	if (!HasInteresting)
13139	HasInteresting = (info != FunctionProtoType::ExtParameterInfo());
13140	}
13141
13142	/// Return a pointer (suitable for setting in an ExtProtoInfo) to the
13143	/// ExtParameterInfo array we've built up.
13144	const FunctionProtoType::ExtParameterInfo *
13145	getPointerOrNull(unsigned numParams) {
13146	if (!HasInteresting)
13147	return nullptr;
13148	Infos.resize(N: numParams);
13149	return Infos.data();
13150	}
13151	};
13152
13153	/// The current instantiation scope used to store local
13154	/// variables.
13155	LocalInstantiationScope *CurrentInstantiationScope;
13156
13157	typedef llvm::DenseMap<ParmVarDecl , llvm::TinyPtrVector<ParmVarDecl >>
13158	UnparsedDefaultArgInstantiationsMap;
13159
13160	/// A mapping from parameters with unparsed default arguments to the
13161	/// set of instantiations of each parameter.
13162	///
13163	/// This mapping is a temporary data structure used when parsing
13164	/// nested class templates or nested classes of class templates,
13165	/// where we might end up instantiating an inner class before the
13166	/// default arguments of its methods have been parsed.
13167	UnparsedDefaultArgInstantiationsMap UnparsedDefaultArgInstantiations;
13168
13169	using InstantiatingSpecializationsKey = llvm::PointerIntPair<Decl *, `2`>;
13170
13171	struct RecursiveInstGuard {
13172	enum class Kind {
13173	Template,
13174	DefaultArgument,
13175	ExceptionSpec,
13176	};
13177
13178	RecursiveInstGuard(Sema &S, Decl *D, Kind Kind)
13179	: S(S), Key (D->getCanonicalDecl(), unsigned(Kind)) {
13180	auto [_, Created] = S.InstantiatingSpecializations.insert(V: Key);
13181	if (!Created)
13182	Key = {};
13183	}
13184
13185	~RecursiveInstGuard() {
13186	if (Key.getOpaqueValue()) {
13187	[[maybe_unused]] bool Erased =
13188	S.InstantiatingSpecializations.erase(V: Key);
13189	assert(Erased);
13190	}
13191	}
13192
13193	RecursiveInstGuard(const RecursiveInstGuard &) = delete;
13194	RecursiveInstGuard &operator=(const RecursiveInstGuard &) = delete;
13195
13196	operator bool() const { return Key.getOpaqueValue() == nullptr; }
13197
13198	private:
13199	Sema &S;
13200	Sema::InstantiatingSpecializationsKey Key;
13201	};
13202
13203	/// A context in which code is being synthesized (where a source location
13204	/// alone is not sufficient to identify the context). This covers template
13205	/// instantiation and various forms of implicitly-generated functions.
13206	struct CodeSynthesisContext {
13207	/// The kind of template instantiation we are performing
13208	enum SynthesisKind {
13209	/// We are instantiating a template declaration. The entity is
13210	/// the declaration we're instantiating (e.g., a CXXRecordDecl).
13211	TemplateInstantiation,
13212
13213	/// We are instantiating a default argument for a template
13214	/// parameter. The Entity is the template parameter whose argument is
13215	/// being instantiated, the Template is the template, and the
13216	/// TemplateArgs/NumTemplateArguments provide the template arguments as
13217	/// specified.
13218	DefaultTemplateArgumentInstantiation,
13219
13220	/// We are instantiating a default argument for a function.
13221	/// The Entity is the ParmVarDecl, and TemplateArgs/NumTemplateArgs
13222	/// provides the template arguments as specified.
13223	DefaultFunctionArgumentInstantiation,
13224
13225	/// We are substituting explicit template arguments provided for
13226	/// a function template. The entity is a FunctionTemplateDecl.
13227	ExplicitTemplateArgumentSubstitution,
13228
13229	/// We are substituting template argument determined as part of
13230	/// template argument deduction for either a class template
13231	/// partial specialization or a function template. The
13232	/// Entity is either a {Class\|Var}TemplatePartialSpecializationDecl or
13233	/// a TemplateDecl.
13234	DeducedTemplateArgumentSubstitution,
13235
13236	/// We are substituting into a lambda expression.
13237	LambdaExpressionSubstitution,
13238
13239	/// We are substituting prior template arguments into a new
13240	/// template parameter. The template parameter itself is either a
13241	/// NonTypeTemplateParmDecl or a TemplateTemplateParmDecl.
13242	PriorTemplateArgumentSubstitution,
13243
13244	/// We are checking the validity of a default template argument that
13245	/// has been used when naming a template-id.
13246	DefaultTemplateArgumentChecking,
13247
13248	/// We are computing the exception specification for a defaulted special
13249	/// member function.
13250	ExceptionSpecEvaluation,
13251
13252	/// We are instantiating the exception specification for a function
13253	/// template which was deferred until it was needed.
13254	ExceptionSpecInstantiation,
13255
13256	/// We are instantiating a requirement of a requires expression.
13257	RequirementInstantiation,
13258
13259	/// We are checking the satisfaction of a nested requirement of a requires
13260	/// expression.
13261	NestedRequirementConstraintsCheck,
13262
13263	/// We are declaring an implicit special member function.
13264	DeclaringSpecialMember,
13265
13266	/// We are declaring an implicit 'operator==' for a defaulted
13267	/// 'operator<=>'.
13268	DeclaringImplicitEqualityComparison,
13269
13270	/// We are defining a synthesized function (such as a defaulted special
13271	/// member).
13272	DefiningSynthesizedFunction,
13273
13274	// We are checking the constraints associated with a constrained entity or
13275	// the constraint expression of a concept. This includes the checks that
13276	// atomic constraints have the type 'bool' and that they can be constant
13277	// evaluated.
13278	ConstraintsCheck,
13279
13280	// We are substituting template arguments into a constraint expression.
13281	ConstraintSubstitution,
13282
13283	// Instantiating a Requires Expression parameter clause.
13284	RequirementParameterInstantiation,
13285
13286	// We are substituting into the parameter mapping of an atomic constraint
13287	// during normalization.
13288	ParameterMappingSubstitution,
13289
13290	/// We are rewriting a comparison operator in terms of an operator<=>.
13291	RewritingOperatorAsSpaceship,
13292
13293	/// We are initializing a structured binding.
13294	InitializingStructuredBinding,
13295
13296	/// We are marking a class as __dllexport.
13297	MarkingClassDllexported,
13298
13299	/// We are building an implied call from __builtin_dump_struct. The
13300	/// arguments are in CallArgs.
13301	BuildingBuiltinDumpStructCall,
13302
13303	/// Added for Template instantiation observation.
13304	/// Memoization means we are _not_ instantiating a template because
13305	/// it is already instantiated (but we entered a context where we
13306	/// would have had to if it was not already instantiated).
13307	Memoization,
13308
13309	/// We are building deduction guides for a class.
13310	BuildingDeductionGuides,
13311
13312	/// We are instantiating a type alias template declaration.
13313	TypeAliasTemplateInstantiation,
13314
13315	/// We are performing partial ordering for template template parameters.
13316	PartialOrderingTTP,
13317
13318	/// We are performing name lookup for a function template or variable
13319	/// template named 'sycl_kernel_launch'.
13320	SYCLKernelLaunchLookup,
13321
13322	/// We are performing overload resolution for a call to a function
13323	/// template or variable template named 'sycl_kernel_launch'.
13324	SYCLKernelLaunchOverloadResolution,
13325
13326	/// We are instantiating an expansion statement.
13327	ExpansionStmtInstantiation,
13328	} Kind;
13329
13330	/// Whether we're substituting into constraints.
13331	bool InConstraintSubstitution;
13332
13333	/// Whether we're substituting into the parameter mapping of a constraint.
13334	bool InParameterMappingSubstitution;
13335
13336	/// The point of instantiation or synthesis within the source code.
13337	SourceLocation PointOfInstantiation;
13338
13339	/// The entity that is being synthesized.
13340	Decl *Entity;
13341
13342	/// The template (or partial specialization) in which we are
13343	/// performing the instantiation, for substitutions of prior template
13344	/// arguments.
13345	NamedDecl *Template;
13346
13347	union {
13348	/// The list of template arguments we are substituting, if they
13349	/// are not part of the entity.
13350	const TemplateArgument *TemplateArgs;
13351
13352	/// The list of argument expressions in a synthesized call.
13353	const Expr *const *CallArgs;
13354	};
13355
13356	// FIXME: Wrap this union around more members, or perhaps store the
13357	// kind-specific members in the RAII object owning the context.
13358	union {
13359	/// The number of template arguments in TemplateArgs.
13360	unsigned NumTemplateArgs;
13361
13362	/// The number of expressions in CallArgs.
13363	unsigned NumCallArgs;
13364
13365	/// The special member being declared or defined.
13366	CXXSpecialMemberKind SpecialMember;
13367	};
13368
13369	ArrayRef<TemplateArgument> template_arguments() const {
13370	assert(Kind != DeclaringSpecialMember);
13371	return {TemplateArgs, NumTemplateArgs};
13372	}
13373
13374	/// The source range that covers the construct that cause
13375	/// the instantiation, e.g., the template-id that causes a class
13376	/// template instantiation.
13377	SourceRange InstantiationRange;
13378
13379	CodeSynthesisContext()
13380	: Kind(TemplateInstantiation), InConstraintSubstitution(false),
13381	InParameterMappingSubstitution(false), Entity(nullptr),
13382	Template(nullptr), TemplateArgs(nullptr), NumTemplateArgs(`0`) {}
13383
13384	/// Determines whether this template is an actual instantiation
13385	/// that should be counted toward the maximum instantiation depth.
13386	bool isInstantiationRecord() const;
13387	};
13388
13389	/// A stack object to be created when performing template
13390	/// instantiation.
13391	///
13392	/// Construction of an object of type \c InstantiatingTemplate
13393	/// pushes the current instantiation onto the stack of active
13394	/// instantiations. If the size of this stack exceeds the maximum
13395	/// number of recursive template instantiations, construction
13396	/// produces an error and evaluates true.
13397	///
13398	/// Destruction of this object will pop the named instantiation off
13399	/// the stack.
13400	struct InstantiatingTemplate {
13401	/// Note that we are instantiating a class template,
13402	/// function template, variable template, alias template,
13403	/// or a member thereof.
13404	InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
13405	Decl *Entity,
13406	SourceRange InstantiationRange = SourceRange ());
13407
13408	struct ExceptionSpecification {};
13409	/// Note that we are instantiating an exception specification
13410	/// of a function template.
13411	InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
13412	FunctionDecl *Entity, ExceptionSpecification,
13413	SourceRange InstantiationRange = SourceRange ());
13414
13415	/// Note that we are instantiating a type alias template declaration.
13416	InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
13417	TypeAliasTemplateDecl *Entity,
13418	ArrayRef<TemplateArgument> TemplateArgs,
13419	SourceRange InstantiationRange = SourceRange ());
13420
13421	/// Note that we are instantiating a default argument in a
13422	/// template-id.
13423	InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
13424	TemplateParameter Param, TemplateDecl *Template,
13425	ArrayRef<TemplateArgument> TemplateArgs,
13426	SourceRange InstantiationRange = SourceRange ());
13427
13428	/// Note that we are substituting either explicitly-specified or
13429	/// deduced template arguments during function template argument deduction.
13430	InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
13431	FunctionTemplateDecl *FunctionTemplate,
13432	ArrayRef<TemplateArgument> TemplateArgs,
13433	CodeSynthesisContext::SynthesisKind Kind,
13434	SourceRange InstantiationRange = SourceRange ());
13435
13436	/// Note that we are instantiating as part of template
13437	/// argument deduction for a class template declaration.
13438	InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
13439	TemplateDecl *Template,
13440	ArrayRef<TemplateArgument> TemplateArgs,
13441	SourceRange InstantiationRange = SourceRange ());
13442
13443	/// Note that we are instantiating as part of template
13444	/// argument deduction for a class template partial
13445	/// specialization.
13446	InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
13447	ClassTemplatePartialSpecializationDecl *PartialSpec,
13448	ArrayRef<TemplateArgument> TemplateArgs,
13449	SourceRange InstantiationRange = SourceRange ());
13450
13451	/// Note that we are instantiating as part of template
13452	/// argument deduction for a variable template partial
13453	/// specialization.
13454	InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
13455	VarTemplatePartialSpecializationDecl *PartialSpec,
13456	ArrayRef<TemplateArgument> TemplateArgs,
13457	SourceRange InstantiationRange = SourceRange ());
13458
13459	/// Note that we are instantiating a default argument for a function
13460	/// parameter.
13461	InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
13462	ParmVarDecl *Param,
13463	ArrayRef<TemplateArgument> TemplateArgs,
13464	SourceRange InstantiationRange = SourceRange ());
13465
13466	/// Note that we are substituting prior template arguments into a
13467	/// non-type parameter.
13468	InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
13469	NamedDecl Template, NonTypeTemplateParmDecl Param,
13470	ArrayRef<TemplateArgument> TemplateArgs,
13471	SourceRange InstantiationRange);
13472
13473	/// Note that we are substituting prior template arguments into a
13474	/// template template parameter.
13475	InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
13476	NamedDecl Template, TemplateTemplateParmDecl Param,
13477	ArrayRef<TemplateArgument> TemplateArgs,
13478	SourceRange InstantiationRange);
13479
13480	/// Note that we are checking the default template argument
13481	/// against the template parameter for a given template-id.
13482	InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
13483	TemplateDecl Template, NamedDecl Param,
13484	ArrayRef<TemplateArgument> TemplateArgs,
13485	SourceRange InstantiationRange);
13486
13487	struct ConstraintsCheck {};
13488	/// \brief Note that we are checking the constraints associated with some
13489	/// constrained entity (a concept declaration or a template with associated
13490	/// constraints).
13491	InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
13492	ConstraintsCheck, NamedDecl *Template,
13493	ArrayRef<TemplateArgument> TemplateArgs,
13494	SourceRange InstantiationRange);
13495
13496	struct ConstraintSubstitution {};
13497	/// \brief Note that we are checking a constraint expression associated
13498	/// with a template declaration or as part of the satisfaction check of a
13499	/// concept.
13500	InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
13501	ConstraintSubstitution, NamedDecl *Template,
13502	SourceRange InstantiationRange);
13503
13504	struct ParameterMappingSubstitution {};
13505	/// \brief Note that we are subtituting into the parameter mapping of an
13506	/// atomic constraint during constraint normalization.
13507	InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
13508	ParameterMappingSubstitution, NamedDecl *Template,
13509	SourceRange InstantiationRange);
13510
13511	/// \brief Note that we are substituting template arguments into a part of
13512	/// a requirement of a requires expression.
13513	InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
13514	concepts::Requirement *Req,
13515	SourceRange InstantiationRange = SourceRange ());
13516
13517	/// \brief Note that we are substituting the body of an expansion statement.
13518	InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
13519	CXXExpansionStmtPattern *ExpansionStmt,
13520	ArrayRef<TemplateArgument> TArgs,
13521	SourceRange InstantiationRange);
13522
13523	/// \brief Note that we are checking the satisfaction of the constraint
13524	/// expression inside of a nested requirement.
13525	InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
13526	concepts::NestedRequirement *Req, ConstraintsCheck,
13527	SourceRange InstantiationRange = SourceRange ());
13528
13529	/// \brief Note that we are checking a requires clause.
13530	InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
13531	const RequiresExpr *E,
13532	SourceRange InstantiationRange);
13533
13534	struct BuildingDeductionGuidesTag {};
13535	/// \brief Note that we are building deduction guides.
13536	InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
13537	TemplateDecl *Entity, BuildingDeductionGuidesTag,
13538	SourceRange InstantiationRange = SourceRange ());
13539
13540	struct PartialOrderingTTP {};
13541	/// \brief Note that we are partial ordering template template parameters.
13542	InstantiatingTemplate(Sema &SemaRef, SourceLocation ArgLoc,
13543	PartialOrderingTTP, TemplateDecl *PArg,
13544	SourceRange InstantiationRange = SourceRange ());
13545
13546	/// Note that we have finished instantiating this template.
13547	void Clear();
13548
13549	~InstantiatingTemplate() { Clear(); }
13550
13551	/// Determines whether we have exceeded the maximum
13552	/// recursive template instantiations.
13553	bool isInvalid() const { return Invalid; }
13554
13555	private:
13556	Sema &SemaRef;
13557	bool Invalid;
13558
13559	InstantiatingTemplate(Sema &SemaRef,
13560	CodeSynthesisContext::SynthesisKind Kind,
13561	SourceLocation PointOfInstantiation,
13562	SourceRange InstantiationRange, Decl *Entity,
13563	NamedDecl Template = nullptr*,
13564	ArrayRef<TemplateArgument> TemplateArgs = {});
13565
13566	InstantiatingTemplate(const InstantiatingTemplate &) = delete;
13567
13568	InstantiatingTemplate &operator=(const InstantiatingTemplate &) = delete;
13569	};
13570
13571	bool SubstTemplateArgument(const TemplateArgumentLoc &Input,
13572	const MultiLevelTemplateArgumentList &TemplateArgs,
13573	TemplateArgumentLoc &Output,
13574	SourceLocation Loc = {},
13575	const DeclarationName &Entity = {});
13576	bool
13577	SubstTemplateArguments(ArrayRef<TemplateArgumentLoc> Args,
13578	const MultiLevelTemplateArgumentList &TemplateArgs,
13579	TemplateArgumentListInfo &Outputs);
13580
13581	/// Substitute concept template arguments in the constraint expression
13582	/// of a concept-id. This is used to implement [temp.constr.normal].
13583	ExprResult
13584	SubstConceptTemplateArguments(const ConceptSpecializationExpr *CSE,
13585	const Expr *ConstraintExpr,
13586	const MultiLevelTemplateArgumentList &MLTAL);
13587
13588	bool SubstTemplateArgumentsInParameterMapping(
13589	ArrayRef<TemplateArgumentLoc> Args, SourceLocation BaseLoc,
13590	const MultiLevelTemplateArgumentList &TemplateArgs,
13591	TemplateArgumentListInfo &Out);
13592
13593	/// Retrieve the template argument list(s) that should be used to
13594	/// instantiate the definition of the given declaration.
13595	///
13596	/// \param ND the declaration for which we are computing template
13597	/// instantiation arguments.
13598	///
13599	/// \param DC In the event we don't HAVE a declaration yet, we instead provide
13600	/// the decl context where it will be created. In this case, the `Innermost`
13601	/// should likely be provided. If ND is non-null, this is ignored.
13602	///
13603	/// \param Innermost if non-NULL, specifies a template argument list for the
13604	/// template declaration passed as ND.
13605	///
13606	/// \param RelativeToPrimary true if we should get the template
13607	/// arguments relative to the primary template, even when we're
13608	/// dealing with a specialization. This is only relevant for function
13609	/// template specializations.
13610	///
13611	/// \param Pattern If non-NULL, indicates the pattern from which we will be
13612	/// instantiating the definition of the given declaration, \p ND. This is
13613	/// used to determine the proper set of template instantiation arguments for
13614	/// friend function template specializations.
13615	///
13616	/// \param ForConstraintInstantiation when collecting arguments,
13617	/// ForConstraintInstantiation indicates we should continue looking when
13618	/// encountering a lambda generic call operator, and continue looking for
13619	/// arguments on an enclosing class template.
13620	///
13621	/// \param SkipForSpecialization when specified, any template specializations
13622	/// in a traversal would be ignored.
13623	///
13624	/// \param ForDefaultArgumentSubstitution indicates we should continue looking
13625	/// when encountering a specialized member function template, rather than
13626	/// returning immediately.
13627	MultiLevelTemplateArgumentList getTemplateInstantiationArgs(
13628	const NamedDecl D, const* DeclContext DC = nullptr, bool* Final = false,
13629	std::optional<ArrayRef<TemplateArgument>> Innermost = std::nullopt,
13630	bool RelativeToPrimary = false, const FunctionDecl Pattern = nullptr*,
13631	bool ForConstraintInstantiation = false,
13632	bool SkipForSpecialization = false,
13633	bool ForDefaultArgumentSubstitution = false);
13634
13635	/// RAII object to handle the state changes required to synthesize
13636	/// a function body.
13637	class SynthesizedFunctionScope {
13638	Sema &S;
13639	Sema::ContextRAII SavedContext;
13640	bool PushedCodeSynthesisContext = false;
13641
13642	public:
13643	SynthesizedFunctionScope(Sema &S, DeclContext *DC)
13644	: S(S), SavedContext (S, DC) {
13645	auto *FD = dyn_cast<FunctionDecl>(Val: DC);
13646	S.PushFunctionScope();
13647	S.PushExpressionEvaluationContextForFunction(
13648	NewContext: ExpressionEvaluationContext::PotentiallyEvaluated, FD);
13649	if (FD)
13650	FD->setWillHaveBody(true);
13651	else
13652	assert(isa<ObjCMethodDecl>(DC));
13653	}
13654
13655	void addContextNote(SourceLocation UseLoc) {
13656	assert(!PushedCodeSynthesisContext);
13657
13658	Sema::CodeSynthesisContext Ctx;
13659	Ctx.Kind = Sema::CodeSynthesisContext::DefiningSynthesizedFunction;
13660	Ctx.PointOfInstantiation = UseLoc;
13661	Ctx.Entity = cast<Decl>(Val: S.CurContext);
13662	S.pushCodeSynthesisContext(Ctx);
13663
13664	PushedCodeSynthesisContext = true;
13665	}
13666
13667	~SynthesizedFunctionScope() {
13668	if (PushedCodeSynthesisContext)
13669	S.popCodeSynthesisContext();
13670	if (auto *FD = dyn_cast<FunctionDecl>(Val: S.CurContext)) {
13671	FD->setWillHaveBody(false);
13672	S.CheckImmediateEscalatingFunctionDefinition(FD, FSI: S.getCurFunction());
13673	}
13674	S.PopExpressionEvaluationContext();
13675	S.PopFunctionScopeInfo();
13676	}
13677
13678	SynthesizedFunctionScope(const SynthesizedFunctionScope &) = delete;
13679	SynthesizedFunctionScope &
13680	operator=(const SynthesizedFunctionScope &) = delete;
13681	};
13682
13683	/// RAII object to ensure that a code synthesis context is popped on scope
13684	/// exit.
13685	class ScopedCodeSynthesisContext {
13686	Sema &S;
13687
13688	public:
13689	ScopedCodeSynthesisContext(Sema &S, const CodeSynthesisContext &Ctx)
13690	: S(S) {
13691	S.pushCodeSynthesisContext(Ctx);
13692	}
13693
13694	~ScopedCodeSynthesisContext() { S.popCodeSynthesisContext(); }
13695	ScopedCodeSynthesisContext(const ScopedCodeSynthesisContext &) = delete;
13696	ScopedCodeSynthesisContext &
13697	operator=(const ScopedCodeSynthesisContext &) = delete;
13698	};
13699
13700	/// List of active code synthesis contexts.
13701	///
13702	/// This vector is treated as a stack. As synthesis of one entity requires
13703	/// synthesis of another, additional contexts are pushed onto the stack.
13704	SmallVector<CodeSynthesisContext, `16`> CodeSynthesisContexts;
13705
13706	/// Specializations whose definitions are currently being instantiated.
13707	llvm::DenseSet<InstantiatingSpecializationsKey> InstantiatingSpecializations;
13708
13709	/// Non-dependent types used in templates that have already been instantiated
13710	/// by some template instantiation.
13711	llvm::DenseSet<QualType> InstantiatedNonDependentTypes;
13712
13713	/// Extra modules inspected when performing a lookup during a template
13714	/// instantiation. Computed lazily.
13715	SmallVector<Module *, `16`> CodeSynthesisContextLookupModules;
13716
13717	/// Cache of additional modules that should be used for name lookup
13718	/// within the current template instantiation. Computed lazily; use
13719	/// getLookupModules() to get a complete set.
13720	llvm::DenseSet<Module *> LookupModulesCache;
13721
13722	/// Map from the most recent declaration of a namespace to the most
13723	/// recent visible declaration of that namespace.
13724	llvm::DenseMap<NamedDecl , NamedDecl > VisibleNamespaceCache;
13725
13726	SFINAETrap CurrentSFINAEContext = nullptr*;
13727
13728	/// The number of \p CodeSynthesisContexts that are not template
13729	/// instantiations and, therefore, should not be counted as part of the
13730	/// instantiation depth.
13731	///
13732	/// When the instantiation depth reaches the user-configurable limit
13733	/// \p LangOptions::InstantiationDepth we will abort instantiation.
13734	// FIXME: Should we have a similar limit for other forms of synthesis?
13735	unsigned NonInstantiationEntries;
13736
13737	/// The depth of the context stack at the point when the most recent
13738	/// error or warning was produced.
13739	///
13740	/// This value is used to suppress printing of redundant context stacks
13741	/// when there are multiple errors or warnings in the same instantiation.
13742	// FIXME: Does this belong in Sema? It's tough to implement it anywhere else.
13743	unsigned LastEmittedCodeSynthesisContextDepth = `0`;
13744
13745	/// The current index into pack expansion arguments that will be
13746	/// used for substitution of parameter packs.
13747	///
13748	/// The pack expansion index will be none to indicate that parameter packs
13749	/// should be instantiated as themselves. Otherwise, the index specifies
13750	/// which argument within the parameter pack will be used for substitution.
13751	UnsignedOrNone ArgPackSubstIndex;
13752
13753	/// RAII object used to change the argument pack substitution index
13754	/// within a \c Sema object.
13755	///
13756	/// See \c ArgPackSubstIndex for more information.
13757	class ArgPackSubstIndexRAII {
13758	Sema &Self;
13759	UnsignedOrNone OldSubstIndex;
13760
13761	public:
13762	ArgPackSubstIndexRAII(Sema &Self, UnsignedOrNone NewSubstIndex)
13763	: Self(Self),
13764	OldSubstIndex(std::exchange(obj&: Self.ArgPackSubstIndex, new_val&: NewSubstIndex)) {}
13765
13766	~ArgPackSubstIndexRAII() { Self.ArgPackSubstIndex = OldSubstIndex; }
13767	ArgPackSubstIndexRAII(const ArgPackSubstIndexRAII &) = delete;
13768	ArgPackSubstIndexRAII &operator=(const ArgPackSubstIndexRAII &) = delete;
13769	};
13770
13771	bool pushCodeSynthesisContext(CodeSynthesisContext Ctx);
13772	void popCodeSynthesisContext();
13773
13774	void PrintContextStack(InstantiationContextDiagFuncRef DiagFunc) {
13775	if (!CodeSynthesisContexts.empty() &&
13776	CodeSynthesisContexts.size() != LastEmittedCodeSynthesisContextDepth) {
13777	PrintInstantiationStack(DiagFunc);
13778	LastEmittedCodeSynthesisContextDepth = CodeSynthesisContexts.size();
13779	}
13780	if (PragmaAttributeCurrentTargetDecl)
13781	PrintPragmaAttributeInstantiationPoint(DiagFunc);
13782	}
13783	void PrintContextStack() { PrintContextStack(DiagFunc: getDefaultDiagFunc()); }
13784	/// Prints the current instantiation stack through a series of
13785	/// notes.
13786	void PrintInstantiationStack(InstantiationContextDiagFuncRef DiagFunc);
13787	void PrintInstantiationStack() {
13788	PrintInstantiationStack(DiagFunc: getDefaultDiagFunc());
13789	}
13790
13791	/// Returns a pointer to the current SFINAE context, if any.
13792	[[nodiscard]] SFINAETrap getSFINAEContext() const* {
13793	return CurrentSFINAEContext;
13794	}
13795	[[nodiscard]] bool isSFINAEContext() const {
13796	return CurrentSFINAEContext != nullptr;
13797	}
13798
13799	/// Perform substitution on the type T with a given set of template
13800	/// arguments.
13801	///
13802	/// This routine substitutes the given template arguments into the
13803	/// type T and produces the instantiated type.
13804	///
13805	/// \param T the type into which the template arguments will be
13806	/// substituted. If this type is not dependent, it will be returned
13807	/// immediately.
13808	///
13809	/// \param Args the template arguments that will be
13810	/// substituted for the top-level template parameters within T.
13811	///
13812	/// \param Loc the location in the source code where this substitution
13813	/// is being performed. It will typically be the location of the
13814	/// declarator (if we're instantiating the type of some declaration)
13815	/// or the location of the type in the source code (if, e.g., we're
13816	/// instantiating the type of a cast expression).
13817	///
13818	/// \param Entity the name of the entity associated with a declaration
13819	/// being instantiated (if any). May be empty to indicate that there
13820	/// is no such entity (if, e.g., this is a type that occurs as part of
13821	/// a cast expression) or that the entity has no name (e.g., an
13822	/// unnamed function parameter).
13823	///
13824	/// \param AllowDeducedTST Whether a DeducedTemplateSpecializationType is
13825	/// acceptable as the top level type of the result.
13826	///
13827	/// \param IsIncompleteSubstitution If provided, the pointee will be set
13828	/// whenever substitution would perform a replacement with a null or
13829	/// non-existent template argument.
13830	///
13831	/// \returns If the instantiation succeeds, the instantiated
13832	/// type. Otherwise, produces diagnostics and returns a NULL type.
13833	TypeSourceInfo SubstType(TypeSourceInfo T,
13834	const MultiLevelTemplateArgumentList &TemplateArgs,
13835	SourceLocation Loc, DeclarationName Entity,
13836	bool AllowDeducedTST = false);
13837
13838	QualType SubstType(QualType T,
13839	const MultiLevelTemplateArgumentList &TemplateArgs,
13840	SourceLocation Loc, DeclarationName Entity,
13841	bool IsIncompleteSubstitution = nullptr*);
13842
13843	TypeSourceInfo *SubstType(TypeLoc TL,
13844	const MultiLevelTemplateArgumentList &TemplateArgs,
13845	SourceLocation Loc, DeclarationName Entity);
13846
13847	TypeSourceInfo *
13848	SubstFriendType(TypeSourceInfo *TSI,
13849	const MultiLevelTemplateArgumentList &TemplateArgs,
13850	SourceLocation Loc, DeclarationName Entity);
13851
13852	/// A form of SubstType intended specifically for instantiating the
13853	/// type of a FunctionDecl. Its purpose is solely to force the
13854	/// instantiation of default-argument expressions and to avoid
13855	/// instantiating an exception-specification.
13856	TypeSourceInfo *SubstFunctionDeclType(
13857	TypeSourceInfo T, const* MultiLevelTemplateArgumentList &TemplateArgs,
13858	SourceLocation Loc, DeclarationName Entity, CXXRecordDecl *ThisContext,
13859	Qualifiers ThisTypeQuals, bool EvaluateConstraints = true);
13860	void SubstExceptionSpec(FunctionDecl New, const* FunctionProtoType *Proto,
13861	const MultiLevelTemplateArgumentList &Args);
13862	bool SubstExceptionSpec(SourceLocation Loc,
13863	FunctionProtoType::ExceptionSpecInfo &ESI,
13864	SmallVectorImpl<QualType> &ExceptionStorage,
13865	const MultiLevelTemplateArgumentList &Args);
13866	ParmVarDecl *
13867	SubstParmVarDecl(ParmVarDecl *D,
13868	const MultiLevelTemplateArgumentList &TemplateArgs,
13869	int indexAdjustment, UnsignedOrNone NumExpansions,
13870	bool ExpectParameterPack, bool EvaluateConstraints = true);
13871
13872	/// Substitute the given template arguments into the given set of
13873	/// parameters, producing the set of parameter types that would be generated
13874	/// from such a substitution.
13875	bool SubstParmTypes(SourceLocation Loc, ArrayRef<ParmVarDecl *> Params,
13876	const FunctionProtoType::ExtParameterInfo *ExtParamInfos,
13877	const MultiLevelTemplateArgumentList &TemplateArgs,
13878	SmallVectorImpl<QualType> &ParamTypes,
13879	SmallVectorImpl<ParmVarDecl > OutParams,
13880	ExtParameterInfoBuilder &ParamInfos);
13881
13882	/// Substitute the given template arguments into the default argument.
13883	bool SubstDefaultArgument(SourceLocation Loc, ParmVarDecl *Param,
13884	const MultiLevelTemplateArgumentList &TemplateArgs,
13885	bool ForCallExpr = false);
13886	ExprResult SubstExpr(Expr *E,
13887	const MultiLevelTemplateArgumentList &TemplateArgs);
13888	/// Substitute an expression as if it is a address-of-operand, which makes it
13889	/// act like a CXXIdExpression rather than an attempt to call.
13890	ExprResult SubstCXXIdExpr(Expr *E,
13891	const MultiLevelTemplateArgumentList &TemplateArgs);
13892
13893	// Must be used instead of SubstExpr at 'constraint checking' time.
13894	ExprResult
13895	SubstConstraintExpr(Expr *E,
13896	const MultiLevelTemplateArgumentList &TemplateArgs);
13897	// Unlike the above, this does not evaluate constraints.
13898	ExprResult SubstConstraintExprWithoutSatisfaction(
13899	Expr E, const* MultiLevelTemplateArgumentList &TemplateArgs);
13900
13901	/// Substitute the given template arguments into a list of
13902	/// expressions, expanding pack expansions if required.
13903	///
13904	/// \param Exprs The list of expressions to substitute into.
13905	///
13906	/// \param IsCall Whether this is some form of call, in which case
13907	/// default arguments will be dropped.
13908	///
13909	/// \param TemplateArgs The set of template arguments to substitute.
13910	///
13911	/// \param Outputs Will receive all of the substituted arguments.
13912	///
13913	/// \returns true if an error occurred, false otherwise.
13914	bool SubstExprs(ArrayRef<Expr > Exprs, bool* IsCall,
13915	const MultiLevelTemplateArgumentList &TemplateArgs,
13916	SmallVectorImpl<Expr *> &Outputs);
13917
13918	StmtResult SubstStmt(Stmt *S,
13919	const MultiLevelTemplateArgumentList &TemplateArgs);
13920
13921	ExprResult
13922	SubstInitializer(Expr E, const* MultiLevelTemplateArgumentList &TemplateArgs,
13923	bool CXXDirectInit);
13924
13925	/// Perform substitution on the base class specifiers of the
13926	/// given class template specialization.
13927	///
13928	/// Produces a diagnostic and returns true on error, returns false and
13929	/// attaches the instantiated base classes to the class template
13930	/// specialization if successful.
13931	bool SubstBaseSpecifiers(CXXRecordDecl Instantiation, CXXRecordDecl Pattern,
13932	const MultiLevelTemplateArgumentList &TemplateArgs);
13933
13934	/// Instantiate the definition of a class from a given pattern.
13935	///
13936	/// \param PointOfInstantiation The point of instantiation within the
13937	/// source code.
13938	///
13939	/// \param Instantiation is the declaration whose definition is being
13940	/// instantiated. This will be either a class template specialization
13941	/// or a member class of a class template specialization.
13942	///
13943	/// \param Pattern is the pattern from which the instantiation
13944	/// occurs. This will be either the declaration of a class template or
13945	/// the declaration of a member class of a class template.
13946	///
13947	/// \param TemplateArgs The template arguments to be substituted into
13948	/// the pattern.
13949	///
13950	/// \param TSK the kind of implicit or explicit instantiation to perform.
13951	///
13952	/// \param Complain whether to complain if the class cannot be instantiated
13953	/// due to the lack of a definition.
13954	///
13955	/// \returns true if an error occurred, false otherwise.
13956	bool InstantiateClass(SourceLocation PointOfInstantiation,
13957	CXXRecordDecl Instantiation, CXXRecordDecl Pattern,
13958	const MultiLevelTemplateArgumentList &TemplateArgs,
13959	TemplateSpecializationKind TSK, bool Complain = true);
13960
13961	private:
13962	bool InstantiateClassImpl(SourceLocation PointOfInstantiation,
13963	CXXRecordDecl *Instantiation,
13964	CXXRecordDecl *Pattern,
13965	const MultiLevelTemplateArgumentList &TemplateArgs,
13966	TemplateSpecializationKind TSK, bool Complain);
13967
13968	public:
13969	/// Instantiate the definition of an enum from a given pattern.
13970	///
13971	/// \param PointOfInstantiation The point of instantiation within the
13972	/// source code.
13973	/// \param Instantiation is the declaration whose definition is being
13974	/// instantiated. This will be a member enumeration of a class
13975	/// temploid specialization, or a local enumeration within a
13976	/// function temploid specialization.
13977	/// \param Pattern The templated declaration from which the instantiation
13978	/// occurs.
13979	/// \param TemplateArgs The template arguments to be substituted into
13980	/// the pattern.
13981	/// \param TSK The kind of implicit or explicit instantiation to perform.
13982	///
13983	/// \return \c true if an error occurred, \c false otherwise.
13984	bool InstantiateEnum(SourceLocation PointOfInstantiation,
13985	EnumDecl Instantiation, EnumDecl Pattern,
13986	const MultiLevelTemplateArgumentList &TemplateArgs,
13987	TemplateSpecializationKind TSK);
13988
13989	/// Instantiate the definition of a field from the given pattern.
13990	///
13991	/// \param PointOfInstantiation The point of instantiation within the
13992	/// source code.
13993	/// \param Instantiation is the declaration whose definition is being
13994	/// instantiated. This will be a class of a class temploid
13995	/// specialization, or a local enumeration within a function temploid
13996	/// specialization.
13997	/// \param Pattern The templated declaration from which the instantiation
13998	/// occurs.
13999	/// \param TemplateArgs The template arguments to be substituted into
14000	/// the pattern.
14001	///
14002	/// \return \c true if an error occurred, \c false otherwise.
14003	bool InstantiateInClassInitializer(
14004	SourceLocation PointOfInstantiation, FieldDecl *Instantiation,
14005	FieldDecl Pattern, const* MultiLevelTemplateArgumentList &TemplateArgs);
14006
14007	bool usesPartialOrExplicitSpecialization(
14008	SourceLocation Loc, ClassTemplateSpecializationDecl *ClassTemplateSpec);
14009
14010	bool InstantiateClassTemplateSpecialization(
14011	SourceLocation PointOfInstantiation,
14012	ClassTemplateSpecializationDecl *ClassTemplateSpec,
14013	TemplateSpecializationKind TSK, bool Complain,
14014	bool PrimaryStrictPackMatch);
14015
14016	/// Instantiates the definitions of all of the member
14017	/// of the given class, which is an instantiation of a class template
14018	/// or a member class of a template.
14019	void
14020	InstantiateClassMembers(SourceLocation PointOfInstantiation,
14021	CXXRecordDecl *Instantiation,
14022	const MultiLevelTemplateArgumentList &TemplateArgs,
14023	TemplateSpecializationKind TSK);
14024
14025	/// Instantiate the definitions of all of the members of the
14026	/// given class template specialization, which was named as part of an
14027	/// explicit instantiation.
14028	void InstantiateClassTemplateSpecializationMembers(
14029	SourceLocation PointOfInstantiation,
14030	ClassTemplateSpecializationDecl *ClassTemplateSpec,
14031	TemplateSpecializationKind TSK);
14032
14033	NestedNameSpecifierLoc SubstNestedNameSpecifierLoc(
14034	NestedNameSpecifierLoc NNS,
14035	const MultiLevelTemplateArgumentList &TemplateArgs);
14036
14037	/// Do template substitution on declaration name info.
14038	DeclarationNameInfo
14039	SubstDeclarationNameInfo(const DeclarationNameInfo &NameInfo,
14040	const MultiLevelTemplateArgumentList &TemplateArgs);
14041	TemplateName
14042	SubstTemplateName(SourceLocation TemplateKWLoc,
14043	NestedNameSpecifierLoc &QualifierLoc, TemplateName Name,
14044	SourceLocation NameLoc,
14045	const MultiLevelTemplateArgumentList &TemplateArgs);
14046
14047	bool SubstTypeConstraint(TemplateTypeParmDecl Inst, const* TypeConstraint *TC,
14048	const MultiLevelTemplateArgumentList &TemplateArgs,
14049	bool EvaluateConstraint);
14050
14051	/// Determine whether we are currently performing template instantiation.
14052	bool inTemplateInstantiation() const {
14053	return CodeSynthesisContexts.size() > NonInstantiationEntries;
14054	}
14055
14056	/// Determine whether we are currently performing constraint substitution.
14057	bool inConstraintSubstitution() const {
14058	return !CodeSynthesisContexts.empty() &&
14059	CodeSynthesisContexts.back().InConstraintSubstitution;
14060	}
14061
14062	bool inParameterMappingSubstitution() const {
14063	return !CodeSynthesisContexts.empty() &&
14064	CodeSynthesisContexts.back().InParameterMappingSubstitution &&
14065	!inConstraintSubstitution();
14066	}
14067
14068	using EntityPrinter = llvm::function_ref<void(llvm::raw_ostream &)>;
14069
14070	/// \brief create a Requirement::SubstitutionDiagnostic with only a
14071	/// SubstitutedEntity and DiagLoc using ASTContext's allocator.
14072	concepts::Requirement::SubstitutionDiagnostic *
14073	createSubstDiagAt(SourceLocation Location, EntityPrinter Printer);
14074
14075	///@}
14076
14077	//
14078	//
14079	// -------------------------------------------------------------------------
14080	//
14081	//
14082
14083	/// \name C++ Template Declaration Instantiation
14084	/// Implementations are in SemaTemplateInstantiateDecl.cpp
14085	///@{
14086
14087	public:
14088	/// An entity for which implicit template instantiation is required.
14089	///
14090	/// The source location associated with the declaration is the first place in
14091	/// the source code where the declaration was "used". It is not necessarily
14092	/// the point of instantiation (which will be either before or after the
14093	/// namespace-scope declaration that triggered this implicit instantiation),
14094	/// However, it is the location that diagnostics should generally refer to,
14095	/// because users will need to know what code triggered the instantiation.
14096	typedef std::pair<ValueDecl *, SourceLocation> PendingImplicitInstantiation;
14097
14098	/// The queue of implicit template instantiations that are required
14099	/// but have not yet been performed.
14100	std::deque<PendingImplicitInstantiation> PendingInstantiations;
14101
14102	/// Queue of implicit template instantiations that cannot be performed
14103	/// eagerly.
14104	SmallVector<PendingImplicitInstantiation, `1`> LateParsedInstantiations;
14105
14106	SmallVector<SmallVector<VTableUse, `16`>, `8`> SavedVTableUses;
14107	SmallVector<std::deque<PendingImplicitInstantiation>, `8`>
14108	SavedPendingInstantiations;
14109
14110	/// The queue of implicit template instantiations that are required
14111	/// and must be performed within the current local scope.
14112	///
14113	/// This queue is only used for member functions of local classes in
14114	/// templates, which must be instantiated in the same scope as their
14115	/// enclosing function, so that they can reference function-local
14116	/// types, static variables, enumerators, etc.
14117	std::deque<PendingImplicitInstantiation> PendingLocalImplicitInstantiations;
14118
14119	class LocalEagerInstantiationScope {
14120	public:
14121	LocalEagerInstantiationScope(Sema &S, bool AtEndOfTU)
14122	: S(S), AtEndOfTU(AtEndOfTU) {
14123	SavedPendingLocalImplicitInstantiations.swap(
14124	x&: S.PendingLocalImplicitInstantiations);
14125	}
14126
14127	void perform() {
14128	S.PerformPendingInstantiations(/LocalOnly=/LocalOnly: true,
14129	/AtEndOfTU=/AtEndOfTU);
14130	}
14131
14132	~LocalEagerInstantiationScope() {
14133	assert(S.PendingLocalImplicitInstantiations.empty() &&
14134	"there shouldn't be any pending local implicit instantiations");
14135	SavedPendingLocalImplicitInstantiations.swap(
14136	x&: S.PendingLocalImplicitInstantiations);
14137	}
14138
14139	LocalEagerInstantiationScope(const LocalEagerInstantiationScope &) = delete;
14140	LocalEagerInstantiationScope &
14141	operator=(const LocalEagerInstantiationScope &) = delete;
14142
14143	private:
14144	Sema &S;
14145	bool AtEndOfTU;
14146	std::deque<PendingImplicitInstantiation>
14147	SavedPendingLocalImplicitInstantiations;
14148	};
14149
14150	/// Records and restores the CurFPFeatures state on entry/exit of compound
14151	/// statements.
14152	class FPFeaturesStateRAII {
14153	public:
14154	FPFeaturesStateRAII(Sema &S);
14155	~FPFeaturesStateRAII();
14156	FPFeaturesStateRAII(const FPFeaturesStateRAII &) = delete;
14157	FPFeaturesStateRAII &operator=(const FPFeaturesStateRAII &) = delete;
14158	FPOptionsOverride getOverrides() { return OldOverrides; }
14159
14160	private:
14161	Sema &S;
14162	FPOptions OldFPFeaturesState;
14163	FPOptionsOverride OldOverrides;
14164	LangOptions::FPEvalMethodKind OldEvalMethod;
14165	SourceLocation OldFPPragmaLocation;
14166	};
14167
14168	class GlobalEagerInstantiationScope {
14169	public:
14170	GlobalEagerInstantiationScope(Sema &S, bool Enabled, bool AtEndOfTU)
14171	: S(S), Enabled(Enabled), AtEndOfTU(AtEndOfTU) {
14172	if (!Enabled)
14173	return;
14174
14175	S.SavedPendingInstantiations.emplace_back();
14176	S.SavedPendingInstantiations.back().swap(x&: S.PendingInstantiations);
14177
14178	S.SavedVTableUses.emplace_back();
14179	S.SavedVTableUses.back().swap(RHS&: S.VTableUses);
14180	}
14181
14182	void perform() {
14183	if (Enabled) {
14184	S.DefineUsedVTables();
14185	S.PerformPendingInstantiations(/LocalOnly=/LocalOnly: false,
14186	/AtEndOfTU=/AtEndOfTU);
14187	}
14188	}
14189
14190	~GlobalEagerInstantiationScope() {
14191	if (!Enabled)
14192	return;
14193
14194	// Restore the set of pending vtables.
14195	assert(S.VTableUses.empty() &&
14196	"VTableUses should be empty before it is discarded.");
14197	S.VTableUses.swap(RHS&: S.SavedVTableUses.back());
14198	S.SavedVTableUses.pop_back();
14199
14200	// Restore the set of pending implicit instantiations.
14201	if ((S.TUKind != TU_Prefix \|\| !S.LangOpts.PCHInstantiateTemplates) &&
14202	AtEndOfTU) {
14203	assert(S.PendingInstantiations.empty() &&
14204	"PendingInstantiations should be empty before it is discarded.");
14205	S.PendingInstantiations.swap(x&: S.SavedPendingInstantiations.back());
14206	S.SavedPendingInstantiations.pop_back();
14207	} else {
14208	// Template instantiations in the PCH may be delayed until the TU.
14209	S.PendingInstantiations.swap(x&: S.SavedPendingInstantiations.back());
14210	S.PendingInstantiations.insert(
14211	position: S.PendingInstantiations.end(),
14212	first: S.SavedPendingInstantiations.back().begin(),
14213	last: S.SavedPendingInstantiations.back().end());
14214	S.SavedPendingInstantiations.pop_back();
14215	}
14216	}
14217
14218	GlobalEagerInstantiationScope(const GlobalEagerInstantiationScope &) =
14219	delete;
14220	GlobalEagerInstantiationScope &
14221	operator=(const GlobalEagerInstantiationScope &) = delete;
14222
14223	private:
14224	Sema &S;
14225	bool Enabled;
14226	bool AtEndOfTU;
14227	};
14228
14229	ExplicitSpecifier instantiateExplicitSpecifier(
14230	const MultiLevelTemplateArgumentList &TemplateArgs, ExplicitSpecifier ES);
14231
14232	struct LateInstantiatedAttribute {
14233	const Attr *TmplAttr;
14234	LocalInstantiationScope *Scope;
14235	Decl *NewDecl;
14236
14237	LateInstantiatedAttribute(const Attr A, LocalInstantiationScope S,
14238	Decl *D)
14239	: TmplAttr(A), Scope(S), NewDecl(D) {}
14240	};
14241	typedef SmallVector<LateInstantiatedAttribute, `1`> LateInstantiatedAttrVec;
14242
14243	/// Recheck instantiated thread-safety attributes that could not be validated
14244	/// on the dependent pattern declaration.
14245	bool checkInstantiatedThreadSafetyAttrs(const Decl D, const* Attr *A);
14246
14247	void InstantiateAttrs(const MultiLevelTemplateArgumentList &TemplateArgs,
14248	const Decl Pattern, Decl Inst,
14249	LateInstantiatedAttrVec LateAttrs = nullptr*,
14250	LocalInstantiationScope OuterMostScope = nullptr*);
14251
14252	/// Update instantiation attributes after template was late parsed.
14253	///
14254	/// Some attributes are evaluated based on the body of template. If it is
14255	/// late parsed, such attributes cannot be evaluated when declaration is
14256	/// instantiated. This function is used to update instantiation attributes
14257	/// when template definition is ready.
14258	void updateAttrsForLateParsedTemplate(const Decl Pattern, Decl Inst);
14259
14260	void
14261	InstantiateAttrsForDecl(const MultiLevelTemplateArgumentList &TemplateArgs,
14262	const Decl Pattern, Decl Inst,
14263	LateInstantiatedAttrVec LateAttrs = nullptr*,
14264	LocalInstantiationScope OuterMostScope = nullptr*);
14265
14266	bool BuildCtorClosureDefaultArgs(SourceLocation Loc, CXXConstructorDecl *Ctor,
14267	bool IsCopy = false);
14268
14269	bool InstantiateDefaultArgument(SourceLocation CallLoc, FunctionDecl *FD,
14270	ParmVarDecl *Param);
14271	void InstantiateExceptionSpec(SourceLocation PointOfInstantiation,
14272	FunctionDecl *Function);
14273
14274	/// Instantiate (or find existing instantiation of) a function template with a
14275	/// given set of template arguments.
14276	///
14277	/// Usually this should not be used, and template argument deduction should be
14278	/// used in its place.
14279	FunctionDecl *InstantiateFunctionDeclaration(
14280	FunctionTemplateDecl FTD, const* TemplateArgumentList *Args,
14281	SourceLocation Loc,
14282	CodeSynthesisContext::SynthesisKind CSC =
14283	CodeSynthesisContext::ExplicitTemplateArgumentSubstitution);
14284
14285	/// Instantiate the definition of the given function from its
14286	/// template.
14287	///
14288	/// \param PointOfInstantiation the point at which the instantiation was
14289	/// required. Note that this is not precisely a "point of instantiation"
14290	/// for the function, but it's close.
14291	///
14292	/// \param Function the already-instantiated declaration of a
14293	/// function template specialization or member function of a class template
14294	/// specialization.
14295	///
14296	/// \param Recursive if true, recursively instantiates any functions that
14297	/// are required by this instantiation.
14298	///
14299	/// \param DefinitionRequired if true, then we are performing an explicit
14300	/// instantiation where the body of the function is required. Complain if
14301	/// there is no such body.
14302	void InstantiateFunctionDefinition(SourceLocation PointOfInstantiation,
14303	FunctionDecl *Function,
14304	bool Recursive = false,
14305	bool DefinitionRequired = false,
14306	bool AtEndOfTU = false);
14307	VarTemplateSpecializationDecl *BuildVarTemplateInstantiation(
14308	VarTemplateDecl VarTemplate, VarDecl FromVar,
14309	const TemplateArgumentList *PartialSpecArgs,
14310	SmallVectorImpl<TemplateArgument> &Converted,
14311	SourceLocation PointOfInstantiation,
14312	LateInstantiatedAttrVec LateAttrs = nullptr*,
14313	LocalInstantiationScope StartingScope = nullptr*);
14314
14315	/// Instantiates a variable template specialization by completing it
14316	/// with appropriate type information and initializer.
14317	VarTemplateSpecializationDecl *CompleteVarTemplateSpecializationDecl(
14318	VarTemplateSpecializationDecl VarSpec, VarDecl PatternDecl,
14319	const MultiLevelTemplateArgumentList &TemplateArgs);
14320
14321	/// BuildVariableInstantiation - Used after a new variable has been created.
14322	/// Sets basic variable data and decides whether to postpone the
14323	/// variable instantiation.
14324	void
14325	BuildVariableInstantiation(VarDecl NewVar, VarDecl OldVar,
14326	const MultiLevelTemplateArgumentList &TemplateArgs,
14327	LateInstantiatedAttrVec *LateAttrs,
14328	DeclContext *Owner,
14329	LocalInstantiationScope *StartingScope,
14330	bool InstantiatingVarTemplate = false,
14331	VarTemplateSpecializationDecl PrevVTSD = nullptr*);
14332
14333	/// Instantiate the initializer of a variable.
14334	void InstantiateVariableInitializer(
14335	VarDecl Var, VarDecl OldVar,
14336	const MultiLevelTemplateArgumentList &TemplateArgs);
14337
14338	/// Instantiate the definition of the given variable from its
14339	/// template.
14340	///
14341	/// \param PointOfInstantiation the point at which the instantiation was
14342	/// required. Note that this is not precisely a "point of instantiation"
14343	/// for the variable, but it's close.
14344	///
14345	/// \param Var the already-instantiated declaration of a templated variable.
14346	///
14347	/// \param Recursive if true, recursively instantiates any functions that
14348	/// are required by this instantiation.
14349	///
14350	/// \param DefinitionRequired if true, then we are performing an explicit
14351	/// instantiation where a definition of the variable is required. Complain
14352	/// if there is no such definition.
14353	void InstantiateVariableDefinition(SourceLocation PointOfInstantiation,
14354	VarDecl Var, bool* Recursive = false,
14355	bool DefinitionRequired = false,
14356	bool AtEndOfTU = false);
14357
14358	void InstantiateMemInitializers(
14359	CXXConstructorDecl New, const* CXXConstructorDecl *Tmpl,
14360	const MultiLevelTemplateArgumentList &TemplateArgs);
14361
14362	/// Find the instantiation of the given declaration within the
14363	/// current instantiation.
14364	///
14365	/// This routine is intended to be used when \p D is a declaration
14366	/// referenced from within a template, that needs to mapped into the
14367	/// corresponding declaration within an instantiation. For example,
14368	/// given:
14369	///
14370	/// \code
14371	/// template<typename T>
14372	/// struct X {
14373	/// enum Kind {
14374	/// KnownValue = sizeof(T)
14375	/// };
14376	///
14377	/// bool getKind() const { return KnownValue; }
14378	/// };
14379	///
14380	/// template struct X<int>;
14381	/// \endcode
14382	///
14383	/// In the instantiation of X<int>::getKind(), we need to map the \p
14384	/// EnumConstantDecl for \p KnownValue (which refers to
14385	/// X<T>::<Kind>::KnownValue) to its instantiation
14386	/// (X<int>::<Kind>::KnownValue).
14387	/// \p FindInstantiatedDecl performs this mapping from within the
14388	/// instantiation of X<int>.
14389	NamedDecl *
14390	FindInstantiatedDecl(SourceLocation Loc, NamedDecl *D,
14391	const MultiLevelTemplateArgumentList &TemplateArgs,
14392	bool FindingInstantiatedContext = false);
14393
14394	/// Finds the instantiation of the given declaration context
14395	/// within the current instantiation.
14396	///
14397	/// \returns NULL if there was an error
14398	DeclContext *
14399	FindInstantiatedContext(SourceLocation Loc, DeclContext *DC,
14400	const MultiLevelTemplateArgumentList &TemplateArgs);
14401
14402	Decl SubstDecl(Decl D, DeclContext *Owner,
14403	const MultiLevelTemplateArgumentList &TemplateArgs);
14404
14405	/// Substitute the name and return type of a defaulted 'operator<=>' to form
14406	/// an implicit 'operator=='.
14407	FunctionDecl SubstSpaceshipAsEqualEqual(CXXRecordDecl RD,
14408	FunctionDecl *Spaceship);
14409
14410	/// Performs template instantiation for all implicit template
14411	/// instantiations we have seen until this point.
14412	void PerformPendingInstantiations(bool LocalOnly = false,
14413	bool AtEndOfTU = true);
14414
14415	TemplateParameterList *
14416	SubstTemplateParams(TemplateParameterList Params, DeclContext Owner,
14417	const MultiLevelTemplateArgumentList &TemplateArgs,
14418	bool EvaluateConstraints = true);
14419
14420	void PerformDependentDiagnostics(
14421	const DeclContext *Pattern,
14422	const MultiLevelTemplateArgumentList &TemplateArgs);
14423
14424	private:
14425	/// Introduce the instantiated local variables into the local
14426	/// instantiation scope.
14427	void addInstantiatedLocalVarsToScope(FunctionDecl *Function,
14428	const FunctionDecl *PatternDecl,
14429	LocalInstantiationScope &Scope);
14430	/// Introduce the instantiated function parameters into the local
14431	/// instantiation scope, and set the parameter names to those used
14432	/// in the template.
14433	bool addInstantiatedParametersToScope(
14434	FunctionDecl Function, const* FunctionDecl *PatternDecl,
14435	LocalInstantiationScope &Scope,
14436	const MultiLevelTemplateArgumentList &TemplateArgs);
14437
14438	/// Introduce the instantiated captures of the lambda into the local
14439	/// instantiation scope.
14440	bool addInstantiatedCapturesToScope(
14441	FunctionDecl Function, const* FunctionDecl *PatternDecl,
14442	LocalInstantiationScope &Scope,
14443	const MultiLevelTemplateArgumentList &TemplateArgs);
14444
14445	int ParsingClassDepth = `0`;
14446
14447	class SavePendingParsedClassStateRAII {
14448	public:
14449	SavePendingParsedClassStateRAII(Sema &S) : S(S) { swapSavedState(); }
14450
14451	~SavePendingParsedClassStateRAII() {
14452	assert(S.DelayedOverridingExceptionSpecChecks.empty() &&
14453	"there shouldn't be any pending delayed exception spec checks");
14454	assert(S.DelayedEquivalentExceptionSpecChecks.empty() &&
14455	"there shouldn't be any pending delayed exception spec checks");
14456	swapSavedState();
14457	}
14458
14459	SavePendingParsedClassStateRAII(const SavePendingParsedClassStateRAII &) =
14460	delete;
14461	SavePendingParsedClassStateRAII &
14462	operator=(const SavePendingParsedClassStateRAII &) = delete;
14463
14464	private:
14465	Sema &S;
14466	decltype(DelayedOverridingExceptionSpecChecks)
14467	SavedOverridingExceptionSpecChecks;
14468	decltype(DelayedEquivalentExceptionSpecChecks)
14469	SavedEquivalentExceptionSpecChecks;
14470
14471	void swapSavedState() {
14472	SavedOverridingExceptionSpecChecks.swap(
14473	RHS&: S.DelayedOverridingExceptionSpecChecks);
14474	SavedEquivalentExceptionSpecChecks.swap(
14475	RHS&: S.DelayedEquivalentExceptionSpecChecks);
14476	}
14477	};
14478
14479	///@}
14480
14481	//
14482	//
14483	// -------------------------------------------------------------------------
14484	//
14485	//
14486
14487	/// \name C++ Variadic Templates
14488	/// Implementations are in SemaTemplateVariadic.cpp
14489	///@{
14490
14491	public:
14492	/// Determine whether an unexpanded parameter pack might be permitted in this
14493	/// location. Useful for error recovery.
14494	bool isUnexpandedParameterPackPermitted();
14495
14496	/// The context in which an unexpanded parameter pack is
14497	/// being diagnosed.
14498	///
14499	/// Note that the values of this enumeration line up with the first
14500	/// argument to the \c err_unexpanded_parameter_pack diagnostic.
14501	enum UnexpandedParameterPackContext {
14502	/// An arbitrary expression.
14503	UPPC_Expression = `0`,
14504
14505	/// The base type of a class type.
14506	UPPC_BaseType,
14507
14508	/// The type of an arbitrary declaration.
14509	UPPC_DeclarationType,
14510
14511	/// The type of a data member.
14512	UPPC_DataMemberType,
14513
14514	/// The size of a bit-field.
14515	UPPC_BitFieldWidth,
14516
14517	/// The expression in a static assertion.
14518	UPPC_StaticAssertExpression,
14519
14520	/// The fixed underlying type of an enumeration.
14521	UPPC_FixedUnderlyingType,
14522
14523	/// The enumerator value.
14524	UPPC_EnumeratorValue,
14525
14526	/// A using declaration.
14527	UPPC_UsingDeclaration,
14528
14529	/// A friend declaration.
14530	UPPC_FriendDeclaration,
14531
14532	/// A declaration qualifier.
14533	UPPC_DeclarationQualifier,
14534
14535	/// An initializer.
14536	UPPC_Initializer,
14537
14538	/// A default argument.
14539	UPPC_DefaultArgument,
14540
14541	/// The type of a non-type template parameter.
14542	UPPC_NonTypeTemplateParameterType,
14543
14544	/// The type of an exception.
14545	UPPC_ExceptionType,
14546
14547	/// Explicit specialization.
14548	UPPC_ExplicitSpecialization,
14549
14550	/// Partial specialization.
14551	UPPC_PartialSpecialization,
14552
14553	/// Microsoft __if_exists.
14554	UPPC_IfExists,
14555
14556	/// Microsoft __if_not_exists.
14557	UPPC_IfNotExists,
14558
14559	/// Lambda expression.
14560	UPPC_Lambda,
14561
14562	/// Block expression.
14563	UPPC_Block,
14564
14565	/// A type constraint.
14566	UPPC_TypeConstraint,
14567
14568	// A requirement in a requires-expression.
14569	UPPC_Requirement,
14570
14571	// A requires-clause.
14572	UPPC_RequiresClause,
14573	};
14574
14575	/// Diagnose unexpanded parameter packs.
14576	///
14577	/// \param Loc The location at which we should emit the diagnostic.
14578	///
14579	/// \param UPPC The context in which we are diagnosing unexpanded
14580	/// parameter packs.
14581	///
14582	/// \param Unexpanded the set of unexpanded parameter packs.
14583	///
14584	/// \returns true if an error occurred, false otherwise.
14585	bool DiagnoseUnexpandedParameterPacks(
14586	SourceLocation Loc, UnexpandedParameterPackContext UPPC,
14587	ArrayRef<UnexpandedParameterPack> Unexpanded);
14588
14589	/// If the given type contains an unexpanded parameter pack,
14590	/// diagnose the error.
14591	///
14592	/// \param Loc The source location where a diagnostc should be emitted.
14593	///
14594	/// \param T The type that is being checked for unexpanded parameter
14595	/// packs.
14596	///
14597	/// \returns true if an error occurred, false otherwise.
14598	bool DiagnoseUnexpandedParameterPack(SourceLocation Loc, TypeSourceInfo *T,
14599	UnexpandedParameterPackContext UPPC);
14600
14601	/// If the given expression contains an unexpanded parameter
14602	/// pack, diagnose the error.
14603	///
14604	/// \param E The expression that is being checked for unexpanded
14605	/// parameter packs.
14606	///
14607	/// \returns true if an error occurred, false otherwise.
14608	bool DiagnoseUnexpandedParameterPack(
14609	Expr *E, UnexpandedParameterPackContext UPPC = UPPC_Expression);
14610
14611	/// If the given requirees-expression contains an unexpanded reference to one
14612	/// of its own parameter packs, diagnose the error.
14613	///
14614	/// \param RE The requiress-expression that is being checked for unexpanded
14615	/// parameter packs.
14616	///
14617	/// \returns true if an error occurred, false otherwise.
14618	bool DiagnoseUnexpandedParameterPackInRequiresExpr(RequiresExpr *RE);
14619
14620	/// If the given nested-name-specifier contains an unexpanded
14621	/// parameter pack, diagnose the error.
14622	///
14623	/// \param SS The nested-name-specifier that is being checked for
14624	/// unexpanded parameter packs.
14625	///
14626	/// \returns true if an error occurred, false otherwise.
14627	bool DiagnoseUnexpandedParameterPack(const CXXScopeSpec &SS,
14628	UnexpandedParameterPackContext UPPC);
14629
14630	/// If the given name contains an unexpanded parameter pack,
14631	/// diagnose the error.
14632	///
14633	/// \param NameInfo The name (with source location information) that
14634	/// is being checked for unexpanded parameter packs.
14635	///
14636	/// \returns true if an error occurred, false otherwise.
14637	bool DiagnoseUnexpandedParameterPack(const DeclarationNameInfo &NameInfo,
14638	UnexpandedParameterPackContext UPPC);
14639
14640	/// If the given template name contains an unexpanded parameter pack,
14641	/// diagnose the error.
14642	///
14643	/// \param Loc The location of the template name.
14644	///
14645	/// \param Template The template name that is being checked for unexpanded
14646	/// parameter packs.
14647	///
14648	/// \returns true if an error occurred, false otherwise.
14649	bool DiagnoseUnexpandedParameterPack(SourceLocation Loc,
14650	TemplateName Template,
14651	UnexpandedParameterPackContext UPPC);
14652
14653	/// If the given template argument contains an unexpanded parameter
14654	/// pack, diagnose the error.
14655	///
14656	/// \param Arg The template argument that is being checked for unexpanded
14657	/// parameter packs.
14658	///
14659	/// \returns true if an error occurred, false otherwise.
14660	bool DiagnoseUnexpandedParameterPack(TemplateArgumentLoc Arg,
14661	UnexpandedParameterPackContext UPPC);
14662
14663	/// Collect the set of unexpanded parameter packs within the given
14664	/// template argument.
14665	///
14666	/// \param Arg The template argument that will be traversed to find
14667	/// unexpanded parameter packs.
14668	void collectUnexpandedParameterPacks(
14669	TemplateArgument Arg,
14670	SmallVectorImpl<UnexpandedParameterPack> &Unexpanded);
14671
14672	/// Collect the set of unexpanded parameter packs within the given
14673	/// template argument.
14674	///
14675	/// \param Arg The template argument that will be traversed to find
14676	/// unexpanded parameter packs.
14677	void collectUnexpandedParameterPacks(
14678	TemplateArgumentLoc Arg,
14679	SmallVectorImpl<UnexpandedParameterPack> &Unexpanded);
14680
14681	/// Collect the set of unexpanded parameter packs within the given
14682	/// type.
14683	///
14684	/// \param T The type that will be traversed to find
14685	/// unexpanded parameter packs.
14686	void collectUnexpandedParameterPacks(
14687	QualType T, SmallVectorImpl<UnexpandedParameterPack> &Unexpanded);
14688
14689	/// Collect the set of unexpanded parameter packs within the given
14690	/// template name.
14691	///
14692	/// \param Template The template name that will be traversed to find
14693	/// unexpanded parameter packs.
14694	void collectUnexpandedParameterPacks(
14695	TemplateName Template,
14696	SmallVectorImpl<UnexpandedParameterPack> &Unexpanded);
14697
14698	/// Collect the set of unexpanded parameter packs within the given
14699	/// type.
14700	///
14701	/// \param TL The type that will be traversed to find
14702	/// unexpanded parameter packs.
14703	void collectUnexpandedParameterPacks(
14704	TypeLoc TL, SmallVectorImpl<UnexpandedParameterPack> &Unexpanded);
14705
14706	/// Collect the set of unexpanded parameter packs within the given
14707	/// nested-name-specifier.
14708	///
14709	/// \param NNS The nested-name-specifier that will be traversed to find
14710	/// unexpanded parameter packs.
14711	void collectUnexpandedParameterPacks(
14712	NestedNameSpecifierLoc NNS,
14713	SmallVectorImpl<UnexpandedParameterPack> &Unexpanded);
14714
14715	/// Collect the set of unexpanded parameter packs within the given
14716	/// name.
14717	///
14718	/// \param NameInfo The name that will be traversed to find
14719	/// unexpanded parameter packs.
14720	void collectUnexpandedParameterPacks(
14721	const DeclarationNameInfo &NameInfo,
14722	SmallVectorImpl<UnexpandedParameterPack> &Unexpanded);
14723
14724	/// Collect the set of unexpanded parameter packs within the given
14725	/// expression.
14726	static void collectUnexpandedParameterPacks(
14727	Expr *E, SmallVectorImpl<UnexpandedParameterPack> &Unexpanded);
14728
14729	/// Invoked when parsing a template argument.
14730	///
14731	/// \param Arg the template argument, which may already be invalid.
14732	///
14733	/// If it is followed by ellipsis, this function is called before
14734	/// `ActOnPackExpansion`.
14735	ParsedTemplateArgument
14736	ActOnTemplateTemplateArgument(const ParsedTemplateArgument &Arg);
14737
14738	/// Invoked when parsing a template argument followed by an
14739	/// ellipsis, which creates a pack expansion.
14740	///
14741	/// \param Arg The template argument preceding the ellipsis, which
14742	/// may already be invalid.
14743	///
14744	/// \param EllipsisLoc The location of the ellipsis.
14745	ParsedTemplateArgument ActOnPackExpansion(const ParsedTemplateArgument &Arg,
14746	SourceLocation EllipsisLoc);
14747
14748	/// Invoked when parsing a type followed by an ellipsis, which
14749	/// creates a pack expansion.
14750	///
14751	/// \param Type The type preceding the ellipsis, which will become
14752	/// the pattern of the pack expansion.
14753	///
14754	/// \param EllipsisLoc The location of the ellipsis.
14755	TypeResult ActOnPackExpansion(ParsedType Type, SourceLocation EllipsisLoc);
14756
14757	/// Construct a pack expansion type from the pattern of the pack
14758	/// expansion.
14759	TypeSourceInfo CheckPackExpansion(TypeSourceInfo Pattern,
14760	SourceLocation EllipsisLoc,
14761	UnsignedOrNone NumExpansions);
14762
14763	/// Construct a pack expansion type from the pattern of the pack
14764	/// expansion.
14765	QualType CheckPackExpansion(QualType Pattern, SourceRange PatternRange,
14766	SourceLocation EllipsisLoc,
14767	UnsignedOrNone NumExpansions);
14768
14769	/// Invoked when parsing an expression followed by an ellipsis, which
14770	/// creates a pack expansion.
14771	///
14772	/// \param Pattern The expression preceding the ellipsis, which will become
14773	/// the pattern of the pack expansion.
14774	///
14775	/// \param EllipsisLoc The location of the ellipsis.
14776	ExprResult ActOnPackExpansion(Expr *Pattern, SourceLocation EllipsisLoc);
14777
14778	/// Invoked when parsing an expression followed by an ellipsis, which
14779	/// creates a pack expansion.
14780	///
14781	/// \param Pattern The expression preceding the ellipsis, which will become
14782	/// the pattern of the pack expansion.
14783	///
14784	/// \param EllipsisLoc The location of the ellipsis.
14785	ExprResult CheckPackExpansion(Expr *Pattern, SourceLocation EllipsisLoc,
14786	UnsignedOrNone NumExpansions);
14787
14788	/// Determine whether we could expand a pack expansion with the
14789	/// given set of parameter packs into separate arguments by repeatedly
14790	/// transforming the pattern.
14791	///
14792	/// \param EllipsisLoc The location of the ellipsis that identifies the
14793	/// pack expansion.
14794	///
14795	/// \param PatternRange The source range that covers the entire pattern of
14796	/// the pack expansion.
14797	///
14798	/// \param Unexpanded The set of unexpanded parameter packs within the
14799	/// pattern.
14800	///
14801	/// \param ShouldExpand Will be set to \c true if the transformer should
14802	/// expand the corresponding pack expansions into separate arguments. When
14803	/// set, \c NumExpansions must also be set.
14804	///
14805	/// \param RetainExpansion Whether the caller should add an unexpanded
14806	/// pack expansion after all of the expanded arguments. This is used
14807	/// when extending explicitly-specified template argument packs per
14808	/// C++0x [temp.arg.explicit]p9.
14809	///
14810	/// \param NumExpansions The number of separate arguments that will be in
14811	/// the expanded form of the corresponding pack expansion. This is both an
14812	/// input and an output parameter, which can be set by the caller if the
14813	/// number of expansions is known a priori (e.g., due to a prior substitution)
14814	/// and will be set by the callee when the number of expansions is known.
14815	/// The callee must set this value when \c ShouldExpand is \c true; it may
14816	/// set this value in other cases.
14817	///
14818	/// \returns true if an error occurred (e.g., because the parameter packs
14819	/// are to be instantiated with arguments of different lengths), false
14820	/// otherwise. If false, \c ShouldExpand (and possibly \c NumExpansions)
14821	/// must be set.
14822	bool CheckParameterPacksForExpansion(
14823	SourceLocation EllipsisLoc, SourceRange PatternRange,
14824	ArrayRef<UnexpandedParameterPack> Unexpanded,
14825	const MultiLevelTemplateArgumentList &TemplateArgs,
14826	bool FailOnPackProducingTemplates, bool &ShouldExpand,
14827	bool &RetainExpansion, UnsignedOrNone &NumExpansions,
14828	bool Diagnose = true);
14829
14830	/// Determine the number of arguments in the given pack expansion
14831	/// type.
14832	///
14833	/// This routine assumes that the number of arguments in the expansion is
14834	/// consistent across all of the unexpanded parameter packs in its pattern.
14835	///
14836	/// Returns an empty Optional if the type can't be expanded.
14837	UnsignedOrNone getNumArgumentsInExpansion(
14838	QualType T, const MultiLevelTemplateArgumentList &TemplateArgs);
14839
14840	UnsignedOrNone getNumArgumentsInExpansionFromUnexpanded(
14841	llvm::ArrayRef<UnexpandedParameterPack> Unexpanded,
14842	const MultiLevelTemplateArgumentList &TemplateArgs);
14843
14844	/// Determine whether the given declarator contains any unexpanded
14845	/// parameter packs.
14846	///
14847	/// This routine is used by the parser to disambiguate function declarators
14848	/// with an ellipsis prior to the ')', e.g.,
14849	///
14850	/// \code
14851	/// void f(T...);
14852	/// \endcode
14853	///
14854	/// To determine whether we have an (unnamed) function parameter pack or
14855	/// a variadic function.
14856	///
14857	/// \returns true if the declarator contains any unexpanded parameter packs,
14858	/// false otherwise.
14859	bool containsUnexpandedParameterPacks(Declarator &D);
14860
14861	/// Returns the pattern of the pack expansion for a template argument.
14862	///
14863	/// \param OrigLoc The template argument to expand.
14864	///
14865	/// \param Ellipsis Will be set to the location of the ellipsis.
14866	///
14867	/// \param NumExpansions Will be set to the number of expansions that will
14868	/// be generated from this pack expansion, if known a priori.
14869	TemplateArgumentLoc
14870	getTemplateArgumentPackExpansionPattern(TemplateArgumentLoc OrigLoc,
14871	SourceLocation &Ellipsis,
14872	UnsignedOrNone &NumExpansions) const;
14873
14874	/// Given a template argument that contains an unexpanded parameter pack, but
14875	/// which has already been substituted, attempt to determine the number of
14876	/// elements that will be produced once this argument is fully-expanded.
14877	///
14878	/// This is intended for use when transforming 'sizeof...(Arg)' in order to
14879	/// avoid actually expanding the pack where possible.
14880	UnsignedOrNone getFullyPackExpandedSize(TemplateArgument Arg);
14881
14882	/// Called when an expression computing the size of a parameter pack
14883	/// is parsed.
14884	///
14885	/// \code
14886	/// template<typename ...Types> struct count {
14887	/// static const unsigned value = sizeof...(Types);
14888	/// };
14889	/// \endcode
14890	///
14891	//
14892	/// \param OpLoc The location of the "sizeof" keyword.
14893	/// \param Name The name of the parameter pack whose size will be determined.
14894	/// \param NameLoc The source location of the name of the parameter pack.
14895	/// \param RParenLoc The location of the closing parentheses.
14896	ExprResult ActOnSizeofParameterPackExpr(Scope *S, SourceLocation OpLoc,
14897	IdentifierInfo &Name,
14898	SourceLocation NameLoc,
14899	SourceLocation RParenLoc);
14900
14901	ExprResult ActOnPackIndexingExpr(Scope S, Expr PackExpression,
14902	SourceLocation EllipsisLoc,
14903	SourceLocation LSquareLoc, Expr *IndexExpr,
14904	SourceLocation RSquareLoc);
14905
14906	ExprResult BuildPackIndexingExpr(Expr *PackExpression,
14907	SourceLocation EllipsisLoc, Expr *IndexExpr,
14908	SourceLocation RSquareLoc,
14909	ArrayRef<Expr *> ExpandedExprs = {},
14910	bool FullySubstituted = false);
14911
14912	TemplateName ActOnPackIndexingTemplateName(TemplateName Pattern,
14913	SourceLocation NameLoc,
14914	Expr *IndexExpr);
14915
14916	TemplateName
14917	BuildPackIndexingTemplateName(TemplateName Pattern, Expr *IndexExpr,
14918	bool FullySubstituted = false,
14919	ArrayRef<TemplateName> Expansions = {});
14920
14921	TypeResult
14922	ActOnPackIndexingDeducedTemplateSpecializationType(TemplateName Name,
14923	SourceLocation NameLoc);
14924
14925	/// Handle a C++1z fold-expression: ( expr op ... op expr ).
14926	ExprResult ActOnCXXFoldExpr(Scope S, SourceLocation LParenLoc, Expr LHS,
14927	tok::TokenKind Operator,
14928	SourceLocation EllipsisLoc, Expr *RHS,
14929	SourceLocation RParenLoc);
14930	ExprResult BuildCXXFoldExpr(UnresolvedLookupExpr *Callee,
14931	SourceLocation LParenLoc, Expr *LHS,
14932	BinaryOperatorKind Operator,
14933	SourceLocation EllipsisLoc, Expr *RHS,
14934	SourceLocation RParenLoc,
14935	UnsignedOrNone NumExpansions);
14936	ExprResult BuildEmptyCXXFoldExpr(SourceLocation EllipsisLoc,
14937	BinaryOperatorKind Operator);
14938
14939	///@}
14940
14941	//
14942	//
14943	// -------------------------------------------------------------------------
14944	//
14945	//
14946
14947	/// \name Constraints and Concepts
14948	/// Implementations are in SemaConcept.cpp
14949	///@{
14950
14951	public:
14952	ExprResult ActOnCXXReflectExpr(SourceLocation OpLoc, TypeSourceInfo *TSI);
14953
14954	ExprResult BuildCXXReflectExpr(SourceLocation OperatorLoc,
14955	TypeSourceInfo *TSI);
14956
14957	public:
14958	void PushSatisfactionStackEntry(const NamedDecl *D,
14959	const llvm::FoldingSetNodeID &ID) {
14960	const NamedDecl *Can = cast<NamedDecl>(Val: D->getCanonicalDecl());
14961	SatisfactionStack.emplace_back(Args&: Can, Args: ID);
14962	}
14963
14964	void PopSatisfactionStackEntry() { SatisfactionStack.pop_back(); }
14965
14966	bool SatisfactionStackContains(const NamedDecl *D,
14967	const llvm::FoldingSetNodeID &ID) const {
14968	const NamedDecl *Can = cast<NamedDecl>(Val: D->getCanonicalDecl());
14969	return llvm::is_contained(Range: SatisfactionStack,
14970	Element: SatisfactionStackEntryTy {Can, ID});
14971	}
14972
14973	using SatisfactionStackEntryTy =
14974	std::pair<const NamedDecl *, llvm::FoldingSetNodeID>;
14975
14976	// Resets the current SatisfactionStack for cases where we are instantiating
14977	// constraints as a 'side effect' of normal instantiation in a way that is not
14978	// indicative of recursive definition.
14979	class SatisfactionStackResetRAII {
14980	llvm::SmallVector<SatisfactionStackEntryTy, `10`> BackupSatisfactionStack;
14981	Sema &SemaRef;
14982
14983	public:
14984	SatisfactionStackResetRAII(Sema &S) : SemaRef(S) {
14985	SemaRef.SwapSatisfactionStack(NewSS&: BackupSatisfactionStack);
14986	}
14987
14988	~SatisfactionStackResetRAII() {
14989	SemaRef.SwapSatisfactionStack(NewSS&: BackupSatisfactionStack);
14990	}
14991
14992	SatisfactionStackResetRAII(const SatisfactionStackResetRAII &) = delete;
14993	SatisfactionStackResetRAII &
14994	operator=(const SatisfactionStackResetRAII &) = delete;
14995	};
14996
14997	void SwapSatisfactionStack(
14998	llvm::SmallVectorImpl<SatisfactionStackEntryTy> &NewSS) {
14999	SatisfactionStack.swap(RHS&: NewSS);
15000	}
15001
15002	using ConstrainedDeclOrNestedRequirement =
15003	llvm::PointerUnion<const NamedDecl *,
15004	const concepts::NestedRequirement *>;
15005
15006	/// Check whether the given expression is a valid constraint expression.
15007	/// A diagnostic is emitted if it is not, false is returned, and
15008	/// PossibleNonPrimary will be set to true if the failure might be due to a
15009	/// non-primary expression being used as an atomic constraint.
15010	bool CheckConstraintExpression(const Expr *CE, Token NextToken = Token (),
15011	bool PossibleNonPrimary = nullptr*,
15012	bool IsTrailingRequiresClause = false);
15013
15014	/// \brief Check whether the given list of constraint expressions are
15015	/// satisfied (as if in a 'conjunction') given template arguments.
15016	/// \param Template the template-like entity that triggered the constraints
15017	/// check (either a concept or a constrained entity).
15018	/// \param ConstraintExprs a list of constraint expressions, treated as if
15019	/// they were 'AND'ed together.
15020	/// \param TemplateArgLists the list of template arguments to substitute into
15021	/// the constraint expression.
15022	/// \param TemplateIDRange The source range of the template id that
15023	/// caused the constraints check.
15024	/// \param Satisfaction if true is returned, will contain details of the
15025	/// satisfaction, with enough information to diagnose an unsatisfied
15026	/// expression.
15027	/// \returns true if an error occurred and satisfaction could not be checked,
15028	/// false otherwise.
15029	bool CheckConstraintSatisfaction(
15030	ConstrainedDeclOrNestedRequirement Entity,
15031	ArrayRef<AssociatedConstraint> AssociatedConstraints,
15032	const MultiLevelTemplateArgumentList &TemplateArgLists,
15033	SourceRange TemplateIDRange, ConstraintSatisfaction &Satisfaction,
15034	const ConceptReference TopLevelConceptId = nullptr*,
15035	Expr ConvertedExpr = nullptr**);
15036
15037	/// Check whether the given function decl's trailing requires clause is
15038	/// satisfied, if any. Returns false and updates Satisfaction with the
15039	/// satisfaction verdict if successful, emits a diagnostic and returns true if
15040	/// an error occurred and satisfaction could not be determined.
15041	///
15042	/// \returns true if an error occurred, false otherwise.
15043	bool CheckFunctionConstraints(const FunctionDecl *FD,
15044	ConstraintSatisfaction &Satisfaction,
15045	SourceLocation UsageLoc = SourceLocation (),
15046	bool ForOverloadResolution = false);
15047
15048	// Calculates whether two constraint expressions are equal irrespective of a
15049	// difference in 'depth'. This takes a pair of optional 'NamedDecl's 'Old' and
15050	// 'New', which are the "source" of the constraint, since this is necessary
15051	// for figuring out the relative 'depth' of the constraint. The depth of the
15052	// 'primary template' and the 'instantiated from' templates aren't necessarily
15053	// the same, such as a case when one is a 'friend' defined in a class.
15054	bool AreConstraintExpressionsEqual(const NamedDecl *Old,
15055	const Expr *OldConstr,
15056	const TemplateCompareNewDeclInfo &New,
15057	const Expr *NewConstr);
15058
15059	// Calculates whether the friend function depends on an enclosing template for
15060	// the purposes of [temp.friend] p9.
15061	bool FriendConstraintsDependOnEnclosingTemplate(const FunctionDecl *FD);
15062
15063	/// \brief Ensure that the given template arguments satisfy the constraints
15064	/// associated with the given template, emitting a diagnostic if they do not.
15065	///
15066	/// \param Template The template to which the template arguments are being
15067	/// provided.
15068	///
15069	/// \param TemplateArgs The converted, canonicalized template arguments.
15070	///
15071	/// \param TemplateIDRange The source range of the template id that
15072	/// caused the constraints check.
15073	///
15074	/// \returns true if the constrains are not satisfied or could not be checked
15075	/// for satisfaction, false if the constraints are satisfied.
15076	bool EnsureTemplateArgumentListConstraints(
15077	TemplateDecl *Template,
15078	const MultiLevelTemplateArgumentList &TemplateArgs,
15079	SourceRange TemplateIDRange);
15080
15081	bool CheckFunctionTemplateConstraints(SourceLocation PointOfInstantiation,
15082	FunctionDecl *Decl,
15083	ArrayRef<TemplateArgument> TemplateArgs,
15084	ConstraintSatisfaction &Satisfaction);
15085
15086	/// \brief Emit diagnostics explaining why a constraint expression was deemed
15087	/// unsatisfied.
15088	/// \param First whether this is the first time an unsatisfied constraint is
15089	/// diagnosed for this error.
15090	void DiagnoseUnsatisfiedConstraint(const ConstraintSatisfaction &Satisfaction,
15091	SourceLocation Loc = {},
15092	bool First = true);
15093
15094	/// \brief Emit diagnostics explaining why a constraint expression was deemed
15095	/// unsatisfied.
15096	void
15097	DiagnoseUnsatisfiedConstraint(const ConceptSpecializationExpr *ConstraintExpr,
15098	bool First = true);
15099
15100	void DiagnoseUnsatisfiedRequiresExpr(const RequiresExpr *RequiresExpr,
15101	bool First = true);
15102
15103	const NormalizedConstraint *getNormalizedAssociatedConstraints(
15104	ConstrainedDeclOrNestedRequirement Entity,
15105	ArrayRef<AssociatedConstraint> AssociatedConstraints);
15106
15107	/// \brief Check whether the given declaration's associated constraints are
15108	/// at least as constrained than another declaration's according to the
15109	/// partial ordering of constraints.
15110	///
15111	/// \param Result If no error occurred, receives the result of true if D1 is
15112	/// at least constrained than D2, and false otherwise.
15113	///
15114	/// \returns true if an error occurred, false otherwise.
15115	bool IsAtLeastAsConstrained(const NamedDecl *D1,
15116	MutableArrayRef<AssociatedConstraint> AC1,
15117	const NamedDecl *D2,
15118	MutableArrayRef<AssociatedConstraint> AC2,
15119	bool &Result);
15120
15121	/// If D1 was not at least as constrained as D2, but would've been if a pair
15122	/// of atomic constraints involved had been declared in a concept and not
15123	/// repeated in two separate places in code.
15124	/// \returns true if such a diagnostic was emitted, false otherwise.
15125	bool MaybeEmitAmbiguousAtomicConstraintsDiagnostic(
15126	const NamedDecl *D1, ArrayRef<AssociatedConstraint> AC1,
15127	const NamedDecl *D2, ArrayRef<AssociatedConstraint> AC2);
15128
15129	/// Cache the satisfaction of an atomic constraint.
15130	/// The key is based on the unsubstituted expression and the parameter
15131	/// mapping. This lets us not substituting the mapping more than once,
15132	/// which is (very!) expensive.
15133	/// FIXME: this should be private.
15134	llvm::DenseMap<llvm::FoldingSetNodeID,
15135	UnsubstitutedConstraintSatisfactionCacheResult>
15136	UnsubstitutedConstraintSatisfactionCache;
15137
15138	/// Cache the instantiation results of template parameter mappings within
15139	/// concepts. Substituting into normalized concepts can be extremely expensive
15140	/// due to the redundancy of template parameters. This cache is intended for
15141	/// use by TemplateInstantiator to avoid redundant semantic checking.
15142	llvm::DenseMap<llvm::FoldingSetNodeID, TemplateArgumentLoc>
15143	CurrentCachedTemplateArgs = nullptr*;
15144
15145	private:
15146	/// Caches pairs of template-like decls whose associated constraints were
15147	/// checked for subsumption and whether or not the first's constraints did in
15148	/// fact subsume the second's.
15149	llvm::DenseMap<std::pair<const NamedDecl , const* NamedDecl >, bool*>
15150	SubsumptionCache;
15151	/// Caches the normalized associated constraints of declarations (concepts or
15152	/// constrained declarations). If an error occurred while normalizing the
15153	/// associated constraints of the template or concept, nullptr will be cached
15154	/// here.
15155	llvm::DenseMap<ConstrainedDeclOrNestedRequirement, NormalizedConstraint *>
15156	NormalizationCache;
15157
15158	/// Cache whether the associated constraint of a declaration
15159	/// is satisfied.
15160	llvm::ContextualFoldingSet<ConstraintSatisfaction, const ASTContext &>
15161	SatisfactionCache;
15162
15163	// The current stack of constraint satisfactions, so we can exit-early.
15164	llvm::SmallVector<SatisfactionStackEntryTy, `10`> SatisfactionStack;
15165
15166	/// Used by SetupConstraintCheckingTemplateArgumentsAndScope to set up the
15167	/// LocalInstantiationScope of the current non-lambda function. For lambdas,
15168	/// use LambdaScopeForCallOperatorInstantiationRAII.
15169	bool
15170	SetupConstraintScope(FunctionDecl *FD,
15171	std::optional<ArrayRef<TemplateArgument>> TemplateArgs,
15172	const MultiLevelTemplateArgumentList &MLTAL,
15173	LocalInstantiationScope &Scope);
15174
15175	/// Used during constraint checking, sets up the constraint template argument
15176	/// lists, and calls SetupConstraintScope to set up the
15177	/// LocalInstantiationScope to have the proper set of ParVarDecls configured.
15178	std::optional<MultiLevelTemplateArgumentList>
15179	SetupConstraintCheckingTemplateArgumentsAndScope(
15180	FunctionDecl *FD, std::optional<ArrayRef<TemplateArgument>> TemplateArgs,
15181	LocalInstantiationScope &Scope);
15182
15183	///@}
15184
15185	//
15186	//
15187	// -------------------------------------------------------------------------
15188	//
15189	//
15190
15191	/// \name Types
15192	/// Implementations are in SemaType.cpp
15193	///@{
15194
15195	public:
15196	/// A mapping that describes the nullability we've seen in each header file.
15197	FileNullabilityMap NullabilityMap;
15198
15199	static int getPrintable(int I) { return I; }
15200	static unsigned getPrintable(unsigned I) { return I; }
15201	static bool getPrintable(bool B) { return B; }
15202	static const char getPrintable(const* char S) { return* S; }
15203	static StringRef getPrintable(StringRef S) { return S; }
15204	static const std::string &getPrintable(const std::string &S) { return S; }
15205	static const IdentifierInfo getPrintable(const* IdentifierInfo *II) {
15206	return II;
15207	}
15208	static DeclarationName getPrintable(DeclarationName N) { return N; }
15209	static QualType getPrintable(QualType T) { return T; }
15210	static SourceRange getPrintable(SourceRange R) { return R; }
15211	static SourceRange getPrintable(SourceLocation L) { return L; }
15212	static SourceRange getPrintable(const Expr E) { return* E->getSourceRange(); }
15213	static SourceRange getPrintable(TypeLoc TL) { return TL.getSourceRange(); }
15214
15215	enum class CompleteTypeKind {
15216	/// Apply the normal rules for complete types. In particular,
15217	/// treat all sizeless types as incomplete.
15218	Normal,
15219
15220	/// Relax the normal rules for complete types so that they include
15221	/// sizeless built-in types.
15222	AcceptSizeless,
15223
15224	// FIXME: Eventually we should flip the default to Normal and opt in
15225	// to AcceptSizeless rather than opt out of it.
15226	Default = AcceptSizeless
15227	};
15228
15229	QualType BuildQualifiedType(QualType T, SourceLocation Loc, Qualifiers Qs,
15230	const DeclSpec DS = nullptr*);
15231	QualType BuildQualifiedType(QualType T, SourceLocation Loc, unsigned CVRA,
15232	const DeclSpec DS = nullptr*);
15233
15234	/// Build a pointer type.
15235	///
15236	/// \param T The type to which we'll be building a pointer.
15237	///
15238	/// \param Loc The location of the entity whose type involves this
15239	/// pointer type or, if there is no such entity, the location of the
15240	/// type that will have pointer type.
15241	///
15242	/// \param Entity The name of the entity that involves the pointer
15243	/// type, if known.
15244	///
15245	/// \returns A suitable pointer type, if there are no
15246	/// errors. Otherwise, returns a NULL type.
15247	QualType BuildPointerType(QualType T, SourceLocation Loc,
15248	DeclarationName Entity);
15249
15250	/// Build a reference type.
15251	///
15252	/// \param T The type to which we'll be building a reference.
15253	///
15254	/// \param Loc The location of the entity whose type involves this
15255	/// reference type or, if there is no such entity, the location of the
15256	/// type that will have reference type.
15257	///
15258	/// \param Entity The name of the entity that involves the reference
15259	/// type, if known.
15260	///
15261	/// \returns A suitable reference type, if there are no
15262	/// errors. Otherwise, returns a NULL type.
15263	QualType BuildReferenceType(QualType T, bool LValueRef, SourceLocation Loc,
15264	DeclarationName Entity);
15265
15266	/// Build an array type.
15267	///
15268	/// \param T The type of each element in the array.
15269	///
15270	/// \param ASM C99 array size modifier (e.g., '', 'static').*
15271	///
15272	/// \param ArraySize Expression describing the size of the array.
15273	///
15274	/// \param Brackets The range from the opening '[' to the closing ']'.
15275	///
15276	/// \param Entity The name of the entity that involves the array
15277	/// type, if known.
15278	///
15279	/// \returns A suitable array type, if there are no errors. Otherwise,
15280	/// returns a NULL type.
15281	QualType BuildArrayType(QualType T, ArraySizeModifier ASM, Expr *ArraySize,
15282	unsigned Quals, SourceRange Brackets,
15283	DeclarationName Entity);
15284	QualType BuildVectorType(QualType T, Expr *VecSize, SourceLocation AttrLoc);
15285
15286	/// Build an ext-vector type.
15287	///
15288	/// Run the required checks for the extended vector type.
15289	QualType BuildExtVectorType(QualType T, Expr *ArraySize,
15290	SourceLocation AttrLoc);
15291	QualType BuildMatrixType(QualType T, Expr NumRows, Expr NumColumns,
15292	SourceLocation AttrLoc);
15293
15294	QualType BuildCountAttributedArrayOrPointerType(QualType WrappedTy,
15295	Expr *CountExpr,
15296	bool CountInBytes,
15297	bool OrNull);
15298
15299	/// BuildAddressSpaceAttr - Builds a DependentAddressSpaceType if an
15300	/// expression is uninstantiated. If instantiated it will apply the
15301	/// appropriate address space to the type. This function allows dependent
15302	/// template variables to be used in conjunction with the address_space
15303	/// attribute
15304	QualType BuildAddressSpaceAttr(QualType &T, LangAS ASIdx, Expr *AddrSpace,
15305	SourceLocation AttrLoc);
15306
15307	/// Same as above, but constructs the AddressSpace index if not provided.
15308	QualType BuildAddressSpaceAttr(QualType &T, Expr *AddrSpace,
15309	SourceLocation AttrLoc);
15310
15311	bool CheckQualifiedFunctionForTypeId(QualType T, SourceLocation Loc);
15312
15313	bool CheckFunctionReturnType(QualType T, SourceLocation Loc);
15314
15315	/// Build a function type.
15316	///
15317	/// This routine checks the function type according to C++ rules and
15318	/// under the assumption that the result type and parameter types have
15319	/// just been instantiated from a template. It therefore duplicates
15320	/// some of the behavior of GetTypeForDeclarator, but in a much
15321	/// simpler form that is only suitable for this narrow use case.
15322	///
15323	/// \param T The return type of the function.
15324	///
15325	/// \param ParamTypes The parameter types of the function. This array
15326	/// will be modified to account for adjustments to the types of the
15327	/// function parameters.
15328	///
15329	/// \param Loc The location of the entity whose type involves this
15330	/// function type or, if there is no such entity, the location of the
15331	/// type that will have function type.
15332	///
15333	/// \param Entity The name of the entity that involves the function
15334	/// type, if known.
15335	///
15336	/// \param EPI Extra information about the function type. Usually this will
15337	/// be taken from an existing function with the same prototype.
15338	///
15339	/// \returns A suitable function type, if there are no errors. The
15340	/// unqualified type will always be a FunctionProtoType.
15341	/// Otherwise, returns a NULL type.
15342	QualType BuildFunctionType(QualType T, MutableArrayRef<QualType> ParamTypes,
15343	SourceLocation Loc, DeclarationName Entity,
15344	const FunctionProtoType::ExtProtoInfo &EPI);
15345
15346	/// Build a member pointer type \c T Class::.*
15347	///
15348	/// \param T the type to which the member pointer refers.
15349	/// \param Class the class type into which the member pointer points.
15350	/// \param Loc the location where this type begins
15351	/// \param Entity the name of the entity that will have this member pointer
15352	/// type
15353	///
15354	/// \returns a member pointer type, if successful, or a NULL type if there was
15355	/// an error.
15356	QualType BuildMemberPointerType(QualType T, const CXXScopeSpec &SS,
15357	CXXRecordDecl *Cls, SourceLocation Loc,
15358	DeclarationName Entity);
15359
15360	/// Build a block pointer type.
15361	///
15362	/// \param T The type to which we'll be building a block pointer.
15363	///
15364	/// \param Loc The source location, used for diagnostics.
15365	///
15366	/// \param Entity The name of the entity that involves the block pointer
15367	/// type, if known.
15368	///
15369	/// \returns A suitable block pointer type, if there are no
15370	/// errors. Otherwise, returns a NULL type.
15371	QualType BuildBlockPointerType(QualType T, SourceLocation Loc,
15372	DeclarationName Entity);
15373
15374	/// Build a paren type including \p T.
15375	QualType BuildParenType(QualType T);
15376	QualType BuildAtomicType(QualType T, SourceLocation Loc);
15377
15378	/// Build a Read-only Pipe type.
15379	///
15380	/// \param T The type to which we'll be building a Pipe.
15381	///
15382	/// \param Loc We do not use it for now.
15383	///
15384	/// \returns A suitable pipe type, if there are no errors. Otherwise, returns
15385	/// a NULL type.
15386	QualType BuildReadPipeType(QualType T, SourceLocation Loc);
15387
15388	/// Build a Write-only Pipe type.
15389	///
15390	/// \param T The type to which we'll be building a Pipe.
15391	///
15392	/// \param Loc We do not use it for now.
15393	///
15394	/// \returns A suitable pipe type, if there are no errors. Otherwise, returns
15395	/// a NULL type.
15396	QualType BuildWritePipeType(QualType T, SourceLocation Loc);
15397
15398	/// Build a bit-precise integer type.
15399	///
15400	/// \param IsUnsigned Boolean representing the signedness of the type.
15401	///
15402	/// \param BitWidth Size of this int type in bits, or an expression
15403	/// representing that.
15404	///
15405	/// \param Loc Location of the keyword.
15406	QualType BuildBitIntType(bool IsUnsigned, Expr *BitWidth, SourceLocation Loc);
15407
15408	/// GetTypeForDeclarator - Convert the type for the specified
15409	/// declarator to Type instances.
15410	///
15411	/// The result of this call will never be null, but the associated
15412	/// type may be a null type if there's an unrecoverable error.
15413	TypeSourceInfo *GetTypeForDeclarator(Declarator &D);
15414	TypeSourceInfo *GetTypeForDeclaratorCast(Declarator &D, QualType FromTy);
15415
15416	/// Package the given type and TSI into a ParsedType.
15417	ParsedType CreateParsedType(QualType T, TypeSourceInfo *TInfo);
15418	static QualType GetTypeFromParser(ParsedType Ty,
15419	TypeSourceInfo TInfo = nullptr**);
15420
15421	TypeResult ActOnTypeName(Declarator &D);
15422
15423	// Check whether the size of array element of type \p EltTy is a multiple of
15424	// its alignment and return false if it isn't.
15425	bool checkArrayElementAlignment(QualType EltTy, SourceLocation Loc);
15426
15427	void
15428	diagnoseIgnoredQualifiers(unsigned DiagID, unsigned Quals,
15429	SourceLocation FallbackLoc,
15430	SourceLocation ConstQualLoc = SourceLocation (),
15431	SourceLocation VolatileQualLoc = SourceLocation (),
15432	SourceLocation RestrictQualLoc = SourceLocation (),
15433	SourceLocation AtomicQualLoc = SourceLocation (),
15434	SourceLocation UnalignedQualLoc = SourceLocation ());
15435
15436	/// Retrieve the keyword associated
15437	IdentifierInfo *getNullabilityKeyword(NullabilityKind nullability);
15438
15439	/// Adjust the calling convention of a method to be the ABI default if it
15440	/// wasn't specified explicitly. This handles method types formed from
15441	/// function type typedefs and typename template arguments.
15442	void adjustMemberFunctionCC(QualType &T, bool HasThisPointer,
15443	bool IsCtorOrDtor, SourceLocation Loc);
15444
15445	// Check if there is an explicit attribute, but only look through parens.
15446	// The intent is to look for an attribute on the current declarator, but not
15447	// one that came from a typedef.
15448	bool hasExplicitCallingConv(QualType T);
15449
15450	/// Check whether a nullability type specifier can be added to the given
15451	/// type through some means not written in source (e.g. API notes).
15452	///
15453	/// \param Type The type to which the nullability specifier will be
15454	/// added. On success, this type will be updated appropriately.
15455	///
15456	/// \param Nullability The nullability specifier to add.
15457	///
15458	/// \param DiagLoc The location to use for diagnostics.
15459	///
15460	/// \param AllowArrayTypes Whether to accept nullability specifiers on an
15461	/// array type (e.g., because it will decay to a pointer).
15462	///
15463	/// \param OverrideExisting Whether to override an existing, locally-specified
15464	/// nullability specifier rather than complaining about the conflict.
15465	///
15466	/// \returns true if nullability cannot be applied, false otherwise.
15467	bool CheckImplicitNullabilityTypeSpecifier(QualType &Type,
15468	NullabilityKind Nullability,
15469	SourceLocation DiagLoc,
15470	bool AllowArrayTypes,
15471	bool OverrideExisting);
15472
15473	/// Check whether the given variable declaration has a size that fits within
15474	/// the address space it is declared in. This issues a diagnostic if not.
15475	///
15476	/// \param VD The variable declaration to check the size of.
15477	///
15478	/// \param AS The address space to check the size of \p VD against.
15479	///
15480	/// \returns true if the variable's size fits within the address space, false
15481	/// otherwise.
15482	bool CheckVarDeclSizeAddressSpace(const VarDecl *VD, LangAS AS);
15483
15484	/// Get the type of expression E, triggering instantiation to complete the
15485	/// type if necessary -- that is, if the expression refers to a templated
15486	/// static data member of incomplete array type.
15487	///
15488	/// May still return an incomplete type if instantiation was not possible or
15489	/// if the type is incomplete for a different reason. Use
15490	/// RequireCompleteExprType instead if a diagnostic is expected for an
15491	/// incomplete expression type.
15492	QualType getCompletedType(Expr *E);
15493
15494	void completeExprArrayBound(Expr *E);
15495
15496	/// Ensure that the type of the given expression is complete.
15497	///
15498	/// This routine checks whether the expression \p E has a complete type. If
15499	/// the expression refers to an instantiable construct, that instantiation is
15500	/// performed as needed to complete its type. Furthermore
15501	/// Sema::RequireCompleteType is called for the expression's type (or in the
15502	/// case of a reference type, the referred-to type).
15503	///
15504	/// \param E The expression whose type is required to be complete.
15505	/// \param Kind Selects which completeness rules should be applied.
15506	/// \param Diagnoser The object that will emit a diagnostic if the type is
15507	/// incomplete.
15508	///
15509	/// \returns \c true if the type of \p E is incomplete and diagnosed, \c false
15510	/// otherwise.
15511	bool RequireCompleteExprType(Expr *E, CompleteTypeKind Kind,
15512	TypeDiagnoser &Diagnoser);
15513	bool RequireCompleteExprType(Expr E, unsigned* DiagID);
15514
15515	template <typename... Ts>
15516	bool RequireCompleteExprType(Expr E, unsigned* DiagID, const Ts &...Args) {
15517	BoundTypeDiagnoser<Ts...> Diagnoser(DiagID, Args...);
15518	return RequireCompleteExprType(E, CompleteTypeKind::Default, Diagnoser);
15519	}
15520
15521	// Returns the underlying type of a decltype with the given expression.
15522	QualType getDecltypeForExpr(Expr *E);
15523
15524	QualType BuildTypeofExprType(Expr *E, TypeOfKind Kind);
15525	/// If AsUnevaluated is false, E is treated as though it were an evaluated
15526	/// context, such as when building a type for decltype(auto).
15527	QualType BuildDecltypeType(Expr E, bool* AsUnevaluated = true);
15528
15529	QualType ActOnPackIndexingType(QualType Pattern, Expr *IndexExpr,
15530	SourceLocation Loc,
15531	SourceLocation EllipsisLoc);
15532	QualType BuildPackIndexingType(QualType Pattern, Expr *IndexExpr,
15533	SourceLocation Loc, SourceLocation EllipsisLoc,
15534	bool FullySubstituted = false,
15535	ArrayRef<QualType> Expansions = {});
15536
15537	using UTTKind = UnaryTransformType::UTTKind;
15538	QualType BuildUnaryTransformType(QualType BaseType, UTTKind UKind,
15539	SourceLocation Loc);
15540	QualType BuiltinEnumUnderlyingType(QualType BaseType, SourceLocation Loc);
15541	QualType BuiltinAddPointer(QualType BaseType, SourceLocation Loc);
15542	QualType BuiltinRemovePointer(QualType BaseType, SourceLocation Loc);
15543	QualType BuiltinDecay(QualType BaseType, SourceLocation Loc);
15544	QualType BuiltinAddReference(QualType BaseType, UTTKind UKind,
15545	SourceLocation Loc);
15546	QualType BuiltinRemoveExtent(QualType BaseType, UTTKind UKind,
15547	SourceLocation Loc);
15548	QualType BuiltinRemoveReference(QualType BaseType, UTTKind UKind,
15549	SourceLocation Loc);
15550
15551	QualType BuiltinRemoveCVRef(QualType BaseType, SourceLocation Loc) {
15552	return BuiltinRemoveReference(BaseType, UKind: UTTKind::RemoveCVRef, Loc);
15553	}
15554
15555	QualType BuiltinChangeCVRQualifiers(QualType BaseType, UTTKind UKind,
15556	SourceLocation Loc);
15557	QualType BuiltinChangeSignedness(QualType BaseType, UTTKind UKind,
15558	SourceLocation Loc);
15559
15560	bool BuiltinIsBaseOf(SourceLocation RhsTLoc, QualType LhsT, QualType RhsT);
15561
15562	/// Ensure that the type T is a literal type.
15563	///
15564	/// This routine checks whether the type @p T is a literal type. If @p T is an
15565	/// incomplete type, an attempt is made to complete it. If @p T is a literal
15566	/// type, or @p AllowIncompleteType is true and @p T is an incomplete type,
15567	/// returns false. Otherwise, this routine issues the diagnostic @p PD (giving
15568	/// it the type @p T), along with notes explaining why the type is not a
15569	/// literal type, and returns true.
15570	///
15571	/// @param Loc The location in the source that the non-literal type
15572	/// diagnostic should refer to.
15573	///
15574	/// @param T The type that this routine is examining for literalness.
15575	///
15576	/// @param Diagnoser Emits a diagnostic if T is not a literal type.
15577	///
15578	/// @returns @c true if @p T is not a literal type and a diagnostic was
15579	/// emitted, @c false otherwise.
15580	bool RequireLiteralType(SourceLocation Loc, QualType T,
15581	TypeDiagnoser &Diagnoser);
15582	bool RequireLiteralType(SourceLocation Loc, QualType T, unsigned DiagID);
15583
15584	template <typename... Ts>
15585	bool RequireLiteralType(SourceLocation Loc, QualType T, unsigned DiagID,
15586	const Ts &...Args) {
15587	BoundTypeDiagnoser<Ts...> Diagnoser(DiagID, Args...);
15588	return RequireLiteralType(Loc, T, Diagnoser);
15589	}
15590
15591	bool isCompleteType(SourceLocation Loc, QualType T,
15592	CompleteTypeKind Kind = CompleteTypeKind::Default) {
15593	return !RequireCompleteTypeImpl(Loc, T, Kind, Diagnoser: nullptr);
15594	}
15595
15596	/// Ensure that the type T is a complete type.
15597	///
15598	/// This routine checks whether the type @p T is complete in any
15599	/// context where a complete type is required. If @p T is a complete
15600	/// type, returns false. If @p T is a class template specialization,
15601	/// this routine then attempts to perform class template
15602	/// instantiation. If instantiation fails, or if @p T is incomplete
15603	/// and cannot be completed, issues the diagnostic @p diag (giving it
15604	/// the type @p T) and returns true.
15605	///
15606	/// @param Loc The location in the source that the incomplete type
15607	/// diagnostic should refer to.
15608	///
15609	/// @param T The type that this routine is examining for completeness.
15610	///
15611	/// @param Kind Selects which completeness rules should be applied.
15612	///
15613	/// @returns @c true if @p T is incomplete and a diagnostic was emitted,
15614	/// @c false otherwise.
15615	bool RequireCompleteType(SourceLocation Loc, QualType T,
15616	CompleteTypeKind Kind, TypeDiagnoser &Diagnoser);
15617	bool RequireCompleteType(SourceLocation Loc, QualType T,
15618	CompleteTypeKind Kind, unsigned DiagID);
15619
15620	bool RequireCompleteType(SourceLocation Loc, QualType T,
15621	TypeDiagnoser &Diagnoser) {
15622	return RequireCompleteType(Loc, T, Kind: CompleteTypeKind::Default, Diagnoser);
15623	}
15624	bool RequireCompleteType(SourceLocation Loc, QualType T, unsigned DiagID) {
15625	return RequireCompleteType(Loc, T, Kind: CompleteTypeKind::Default, DiagID);
15626	}
15627
15628	template <typename... Ts>
15629	bool RequireCompleteType(SourceLocation Loc, QualType T, unsigned DiagID,
15630	const Ts &...Args) {
15631	BoundTypeDiagnoser<Ts...> Diagnoser(DiagID, Args...);
15632	return RequireCompleteType(Loc, T, Diagnoser);
15633	}
15634
15635	/// Determine whether a declaration is visible to name lookup.
15636	bool isVisible(const NamedDecl *D) {
15637	return D->isUnconditionallyVisible() \|\|
15638	isAcceptableSlow(D, Kind: AcceptableKind::Visible);
15639	}
15640
15641	/// Determine whether a declaration is reachable.
15642	bool isReachable(const NamedDecl *D) {
15643	// All visible declarations are reachable.
15644	return D->isUnconditionallyVisible() \|\|
15645	isAcceptableSlow(D, Kind: AcceptableKind::Reachable);
15646	}
15647
15648	/// Determine whether a declaration is acceptable (visible/reachable).
15649	bool isAcceptable(const NamedDecl *D, AcceptableKind Kind) {
15650	return Kind == AcceptableKind::Visible ? isVisible(D) : isReachable(D);
15651	}
15652
15653	/// Determine if \p D and \p Suggested have a structurally compatible
15654	/// layout as described in C11 6.2.7/1.
15655	bool hasStructuralCompatLayout(Decl D, Decl Suggested);
15656
15657	/// Determine if \p D has a visible definition. If not, suggest a declaration
15658	/// that should be made visible to expose the definition.
15659	bool hasVisibleDefinition(NamedDecl D, NamedDecl *Suggested,
15660	bool OnlyNeedComplete = false);
15661	bool hasVisibleDefinition(const NamedDecl *D) {
15662	NamedDecl *Hidden;
15663	return hasVisibleDefinition(D: const_cast<NamedDecl *>(D), Suggested: &Hidden);
15664	}
15665	/// Determine if \p D has a definition which allows we redefine it in current
15666	/// TU. \p Suggested is the definition that should be made visible to expose
15667	/// the definition.
15668	bool isRedefinitionAllowedFor(NamedDecl D, NamedDecl *Suggested,
15669	bool &Visible);
15670	bool isRedefinitionAllowedFor(const NamedDecl D, bool* &Visible) {
15671	NamedDecl *Hidden;
15672	return isRedefinitionAllowedFor(D: const_cast<NamedDecl *>(D), Suggested: &Hidden,
15673	Visible);
15674	}
15675
15676	/// Determine if \p D has a reachable definition. If not, suggest a
15677	/// declaration that should be made reachable to expose the definition.
15678	bool hasReachableDefinition(NamedDecl D, NamedDecl *Suggested,
15679	bool OnlyNeedComplete = false);
15680	bool hasReachableDefinition(NamedDecl *D) {
15681	NamedDecl *Hidden;
15682	return hasReachableDefinition(D, Suggested: &Hidden);
15683	}
15684
15685	bool hasAcceptableDefinition(NamedDecl D, NamedDecl *Suggested,
15686	AcceptableKind Kind,
15687	bool OnlyNeedComplete = false);
15688	bool hasAcceptableDefinition(NamedDecl *D, AcceptableKind Kind) {
15689	NamedDecl *Hidden;
15690	return hasAcceptableDefinition(D, Suggested: &Hidden, Kind);
15691	}
15692
15693	/// Try to parse the conditional expression attached to an effect attribute
15694	/// (e.g. 'nonblocking'). (c.f. Sema::ActOnNoexceptSpec). Return an empty
15695	/// optional on error.
15696	std::optional<FunctionEffectMode>
15697	ActOnEffectExpression(Expr *CondExpr, StringRef AttributeName);
15698
15699	void ActOnCleanupAttr(Decl D, const* Attr *A);
15700	void ActOnInitPriorityAttr(Decl D, const* Attr *A);
15701
15702	private:
15703	/// The implementation of RequireCompleteType
15704	bool RequireCompleteTypeImpl(SourceLocation Loc, QualType T,
15705	CompleteTypeKind Kind, TypeDiagnoser *Diagnoser);
15706
15707	/// Nullability type specifiers.
15708	IdentifierInfo Ident__Nonnull = nullptr*;
15709	IdentifierInfo Ident__Nullable = nullptr*;
15710	IdentifierInfo Ident__Nullable_result = nullptr*;
15711	IdentifierInfo Ident__Null_unspecified = nullptr*;
15712
15713	///@}
15714
15715	//
15716	//
15717	// -------------------------------------------------------------------------
15718	//
15719	//
15720
15721	/// \name FixIt Helpers
15722	/// Implementations are in SemaFixItUtils.cpp
15723	///@{
15724
15725	public:
15726	/// Get a string to suggest for zero-initialization of a type.
15727	std::string getFixItZeroInitializerForType(QualType T,
15728	SourceLocation Loc) const;
15729	std::string getFixItZeroLiteralForType(QualType T, SourceLocation Loc) const;
15730
15731	///@}
15732
15733	//
15734	//
15735	// -------------------------------------------------------------------------
15736	//
15737	//
15738
15739	/// \name Function Effects
15740	/// Implementations are in SemaFunctionEffects.cpp
15741	///@{
15742	public:
15743	struct FunctionEffectDiff {
15744	enum class Kind { Added, Removed, ConditionMismatch };
15745
15746	FunctionEffect::Kind EffectKind;
15747	Kind DiffKind;
15748	std::optional<FunctionEffectWithCondition>
15749	Old; // Invalid when 'Kind' is 'Added'.
15750	std::optional<FunctionEffectWithCondition>
15751	New; // Invalid when 'Kind' is 'Removed'.
15752
15753	StringRef effectName() const {
15754	if (Old)
15755	return Old.value().Effect.name();
15756	return New.value().Effect.name();
15757	}
15758
15759	/// Describes the result of effects differing between a base class's virtual
15760	/// method and an overriding method in a subclass.
15761	enum class OverrideResult {
15762	NoAction,
15763	Warn,
15764	Merge // Merge missing effect from base to derived.
15765	};
15766
15767	/// Return true if adding or removing the effect as part of a type
15768	/// conversion should generate a diagnostic.
15769	bool shouldDiagnoseConversion(QualType SrcType,
15770	const FunctionEffectsRef &SrcFX,
15771	QualType DstType,
15772	const FunctionEffectsRef &DstFX) const;
15773
15774	/// Return true if adding or removing the effect in a redeclaration should
15775	/// generate a diagnostic.
15776	bool shouldDiagnoseRedeclaration(const FunctionDecl &OldFunction,
15777	const FunctionEffectsRef &OldFX,
15778	const FunctionDecl &NewFunction,
15779	const FunctionEffectsRef &NewFX) const;
15780
15781	/// Return true if adding or removing the effect in a C++ virtual method
15782	/// override should generate a diagnostic.
15783	OverrideResult shouldDiagnoseMethodOverride(
15784	const CXXMethodDecl &OldMethod, const FunctionEffectsRef &OldFX,
15785	const CXXMethodDecl &NewMethod, const FunctionEffectsRef &NewFX) const;
15786	};
15787
15788	struct FunctionEffectDiffVector : public SmallVector<FunctionEffectDiff> {
15789	/// Caller should short-circuit by checking for equality first.
15790	FunctionEffectDiffVector(const FunctionEffectsRef &Old,
15791	const FunctionEffectsRef &New);
15792	};
15793
15794	/// All functions/lambdas/blocks which have bodies and which have a non-empty
15795	/// FunctionEffectsRef to be verified.
15796	SmallVector<const Decl *> DeclsWithEffectsToVerify;
15797
15798	/// The union of all effects present on DeclsWithEffectsToVerify. Conditions
15799	/// are all null.
15800	FunctionEffectKindSet AllEffectsToVerify;
15801
15802	public:
15803	/// Warn and return true if adding a function effect to a set would create a
15804	/// conflict.
15805	bool diagnoseConflictingFunctionEffect(const FunctionEffectsRef &FX,
15806	const FunctionEffectWithCondition &EC,
15807	SourceLocation NewAttrLoc);
15808
15809	// Report a failure to merge function effects between declarations due to a
15810	// conflict.
15811	void
15812	diagnoseFunctionEffectMergeConflicts(const FunctionEffectSet::Conflicts &Errs,
15813	SourceLocation NewLoc,
15814	SourceLocation OldLoc);
15815
15816	/// Inline checks from the start of maybeAddDeclWithEffects, to
15817	/// minimize performance impact on code not using effects.
15818	template <class FuncOrBlockDecl>
15819	void maybeAddDeclWithEffects(FuncOrBlockDecl *D) {
15820	if (Context.hasAnyFunctionEffects())
15821	if (FunctionEffectsRef FX = D->getFunctionEffects(); !FX.empty())
15822	maybeAddDeclWithEffects(D, FX);
15823	}
15824
15825	/// Potentially add a FunctionDecl or BlockDecl to DeclsWithEffectsToVerify.
15826	void maybeAddDeclWithEffects(const Decl D, const* FunctionEffectsRef &FX);
15827
15828	/// Unconditionally add a Decl to DeclsWithEfffectsToVerify.
15829	void addDeclWithEffects(const Decl D, const* FunctionEffectsRef &FX);
15830
15831	void performFunctionEffectAnalysis(TranslationUnitDecl *TU);
15832
15833	///@}
15834
15835	//
15836	//
15837	// -------------------------------------------------------------------------
15838	//
15839	//
15840
15841	/// \name Expansion Statements
15842	/// Implementations are in SemaExpand.cpp
15843	///@{
15844	public:
15845	CXXExpansionStmtDecl ActOnCXXExpansionStmtDecl(unsigned* TemplateDepth,
15846	SourceLocation TemplateKWLoc);
15847
15848	CXXExpansionStmtDecl *
15849	BuildCXXExpansionStmtDecl(DeclContext *Ctx, SourceLocation TemplateKWLoc,
15850	NonTypeTemplateParmDecl *NTTP);
15851
15852	ExprResult ActOnCXXExpansionInitList(MultiExprArg SubExprs,
15853	SourceLocation LBraceLoc,
15854	SourceLocation RBraceLoc);
15855
15856	StmtResult ActOnCXXExpansionStmtPattern(
15857	CXXExpansionStmtDecl ESD, Stmt Init, Stmt *ExpansionVarStmt,
15858	Expr *ExpansionInitializer, SourceLocation LParenLoc,
15859	SourceLocation ColonLoc, SourceLocation RParenLoc,
15860	ArrayRef<MaterializeTemporaryExpr *> LifetimeExtendTemps);
15861
15862	StmtResult FinishCXXExpansionStmt(Stmt Expansion, Stmt Body);
15863
15864	StmtResult BuildCXXEnumeratingExpansionStmtPattern(Decl ESD, Stmt Init,
15865	Stmt *ExpansionVar,
15866	SourceLocation LParenLoc,
15867	SourceLocation ColonLoc,
15868	SourceLocation RParenLoc);
15869
15870	StmtResult BuildNonEnumeratingCXXExpansionStmtPattern(
15871	CXXExpansionStmtDecl ESD, Stmt Init, DeclStmt *ExpansionVarStmt,
15872	Expr *ExpansionInitializer, SourceLocation LParenLoc,
15873	SourceLocation ColonLoc, SourceLocation RParenLoc,
15874	ArrayRef<MaterializeTemporaryExpr *> LifetimeExtendTemps = {});
15875
15876	ExprResult BuildCXXExpansionSelectExpr(InitListExpr Range, Expr Idx);
15877
15878	std::optional<uint64_t>
15879	ComputeExpansionSize(CXXExpansionStmtPattern *Expansion);
15880	///@}
15881	};
15882
15883	DeductionFailureInfo
15884	MakeDeductionFailureInfo(ASTContext &Context, TemplateDeductionResult TDK,
15885	sema::TemplateDeductionInfo &Info);
15886
15887	/// Contains a late templated function.
15888	/// Will be parsed at the end of the translation unit, used by Sema & Parser.
15889	struct LateParsedTemplate {
15890	CachedTokens Toks;
15891	/// The template function declaration to be late parsed.
15892	Decl *D;
15893	/// Floating-point options in the point of definition.
15894	FPOptions FPO;
15895	};
15896
15897	template <>
15898	void Sema::PragmaStack<Sema::AlignPackInfo>::Act(SourceLocation PragmaLocation,
15899	PragmaMsStackAction Action,
15900	llvm::StringRef StackSlotLabel,
15901	AlignPackInfo Value);
15902
15903	} // end namespace clang
15904
15905	#endif
15906

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