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/Builtins.h"
39	#include "clang/Basic/CapturedStmt.h"
40	#include "clang/Basic/Cuda.h"
41	#include "clang/Basic/DiagnosticSema.h"
42	#include "clang/Basic/ExceptionSpecificationType.h"
43	#include "clang/Basic/ExpressionTraits.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/Basic/TypeTraits.h"
58	#include "clang/Sema/AnalysisBasedWarnings.h"
59	#include "clang/Sema/Attr.h"
60	#include "clang/Sema/CleanupInfo.h"
61	#include "clang/Sema/DeclSpec.h"
62	#include "clang/Sema/ExternalSemaSource.h"
63	#include "clang/Sema/IdentifierResolver.h"
64	#include "clang/Sema/Ownership.h"
65	#include "clang/Sema/ParsedAttr.h"
66	#include "clang/Sema/Redeclaration.h"
67	#include "clang/Sema/Scope.h"
68	#include "clang/Sema/SemaBase.h"
69	#include "clang/Sema/SemaConcept.h"
70	#include "clang/Sema/SemaRISCV.h"
71	#include "clang/Sema/TypoCorrection.h"
72	#include "clang/Sema/Weak.h"
73	#include "llvm/ADT/APInt.h"
74	#include "llvm/ADT/ArrayRef.h"
75	#include "llvm/ADT/BitmaskEnum.h"
76	#include "llvm/ADT/DenseMap.h"
77	#include "llvm/ADT/DenseSet.h"
78	#include "llvm/ADT/FloatingPointMode.h"
79	#include "llvm/ADT/FoldingSet.h"
80	#include "llvm/ADT/MapVector.h"
81	#include "llvm/ADT/PointerIntPair.h"
82	#include "llvm/ADT/PointerUnion.h"
83	#include "llvm/ADT/STLExtras.h"
84	#include "llvm/ADT/STLForwardCompat.h"
85	#include "llvm/ADT/STLFunctionalExtras.h"
86	#include "llvm/ADT/SetVector.h"
87	#include "llvm/ADT/SmallBitVector.h"
88	#include "llvm/ADT/SmallPtrSet.h"
89	#include "llvm/ADT/SmallSet.h"
90	#include "llvm/ADT/SmallVector.h"
91	#include "llvm/ADT/StringExtras.h"
92	#include "llvm/ADT/StringMap.h"
93	#include "llvm/ADT/TinyPtrVector.h"
94	#include "llvm/Support/Allocator.h"
95	#include "llvm/Support/Compiler.h"
96	#include "llvm/Support/Error.h"
97	#include "llvm/Support/ErrorHandling.h"
98	#include <cassert>
99	#include <climits>
100	#include <cstddef>
101	#include <cstdint>
102	#include <deque>
103	#include <functional>
104	#include <iterator>
105	#include <memory>
106	#include <optional>
107	#include <string>
108	#include <tuple>
109	#include <type_traits>
110	#include <utility>
111	#include <vector>
112
113	namespace llvm {
114	struct InlineAsmIdentifierInfo;
115	} // namespace llvm
116
117	namespace clang {
118	class ADLResult;
119	class APValue;
120	struct ASTConstraintSatisfaction;
121	class ASTConsumer;
122	class ASTContext;
123	class ASTDeclReader;
124	class ASTMutationListener;
125	class ASTReader;
126	class ASTWriter;
127	class CXXBasePath;
128	class CXXBasePaths;
129	class CXXFieldCollector;
130	class CodeCompleteConsumer;
131	enum class ComparisonCategoryType : unsigned char;
132	class ConstraintSatisfaction;
133	class DarwinSDKInfo;
134	class DeclGroupRef;
135	class DeducedTemplateArgument;
136	struct DeductionFailureInfo;
137	class DependentDiagnostic;
138	class Designation;
139	class IdentifierInfo;
140	class ImplicitConversionSequence;
141	typedef MutableArrayRef<ImplicitConversionSequence> ConversionSequenceList;
142	class InitializationKind;
143	class InitializationSequence;
144	class InitializedEntity;
145	enum class LangAS : unsigned int;
146	class LocalInstantiationScope;
147	class LookupResult;
148	class MangleNumberingContext;
149	typedef ArrayRef<IdentifierLoc> ModuleIdPath;
150	class ModuleLoader;
151	class MultiLevelTemplateArgumentList;
152	struct NormalizedConstraint;
153	class ObjCInterfaceDecl;
154	class ObjCMethodDecl;
155	struct OverloadCandidate;
156	enum class OverloadCandidateParamOrder : char;
157	enum OverloadCandidateRewriteKind : unsigned;
158	class OverloadCandidateSet;
159	class Preprocessor;
160	class SemaAMDGPU;
161	class SemaARM;
162	class SemaAVR;
163	class SemaBPF;
164	class SemaCodeCompletion;
165	class SemaCUDA;
166	class SemaDirectX;
167	class SemaHLSL;
168	class SemaHexagon;
169	class SemaLoongArch;
170	class SemaM68k;
171	class SemaMIPS;
172	class SemaMSP430;
173	class SemaNVPTX;
174	class SemaObjC;
175	class SemaOpenACC;
176	class SemaOpenCL;
177	class SemaOpenMP;
178	class SemaPPC;
179	class SemaPseudoObject;
180	class SemaRISCV;
181	class SemaSPIRV;
182	class SemaSYCL;
183	class SemaSwift;
184	class SemaSystemZ;
185	class SemaWasm;
186	class SemaX86;
187	class StandardConversionSequence;
188	class TemplateArgument;
189	class TemplateArgumentLoc;
190	class TemplateInstantiationCallback;
191	class TemplatePartialOrderingContext;
192	class TemplateSpecCandidateSet;
193	class Token;
194	class TypeConstraint;
195	class TypoCorrectionConsumer;
196	class UnresolvedSetImpl;
197	class UnresolvedSetIterator;
198	class VisibleDeclConsumer;
199
200	namespace sema {
201	class BlockScopeInfo;
202	class Capture;
203	class CapturedRegionScopeInfo;
204	class CapturingScopeInfo;
205	class CompoundScopeInfo;
206	class DelayedDiagnostic;
207	class DelayedDiagnosticPool;
208	class FunctionScopeInfo;
209	class LambdaScopeInfo;
210	class SemaPPCallbacks;
211	class TemplateDeductionInfo;
212	} // namespace sema
213
214	// AssignmentAction - This is used by all the assignment diagnostic functions
215	// to represent what is actually causing the operation
216	enum class AssignmentAction {
217	Assigning,
218	Passing,
219	Returning,
220	Converting,
221	Initializing,
222	Sending,
223	Casting,
224	Passing_CFAudited
225	};
226
227	namespace threadSafety {
228	class BeforeSet;
229	void threadSafetyCleanup(BeforeSet *Cache);
230	} // namespace threadSafety
231
232	// FIXME: No way to easily map from TemplateTypeParmTypes to
233	// TemplateTypeParmDecls, so we have this horrible PointerUnion.
234	typedef std::pair<llvm::PointerUnion<const TemplateTypeParmType , NamedDecl ,
235	const TemplateSpecializationType *,
236	const SubstBuiltinTemplatePackType *>,
237	SourceLocation>
238	UnexpandedParameterPack;
239
240	/// Describes whether we've seen any nullability information for the given
241	/// file.
242	struct FileNullability {
243	/// The first pointer declarator (of any pointer kind) in the file that does
244	/// not have a corresponding nullability annotation.
245	SourceLocation PointerLoc;
246
247	/// The end location for the first pointer declarator in the file. Used for
248	/// placing fix-its.
249	SourceLocation PointerEndLoc;
250
251	/// Which kind of pointer declarator we saw.
252	uint8_t PointerKind;
253
254	/// Whether we saw any type nullability annotations in the given file.
255	bool SawTypeNullability = false;
256	};
257
258	/// A mapping from file IDs to a record of whether we've seen nullability
259	/// information in that file.
260	class FileNullabilityMap {
261	/// A mapping from file IDs to the nullability information for each file ID.
262	llvm::DenseMap<FileID, FileNullability> Map;
263
264	/// A single-element cache based on the file ID.
265	struct {
266	FileID File;
267	FileNullability Nullability;
268	} Cache;
269
270	public:
271	FileNullability &operator[](FileID file) {
272	// Check the single-element cache.
273	if (file == Cache.File)
274	return Cache.Nullability;
275
276	// It's not in the single-element cache; flush the cache if we have one.
277	if (!Cache.File.isInvalid()) {
278	Map [Cache.File] = Cache.Nullability;
279	}
280
281	// Pull this entry into the cache.
282	Cache.File = file;
283	Cache.Nullability = Map [file];
284	return Cache.Nullability;
285	}
286	};
287
288	/// Tracks expected type during expression parsing, for use in code completion.
289	/// The type is tied to a particular token, all functions that update or consume
290	/// the type take a start location of the token they are looking at as a
291	/// parameter. This avoids updating the type on hot paths in the parser.
292	class PreferredTypeBuilder {
293	public:
294	PreferredTypeBuilder(ASTContext Ctx, bool* Enabled)
295	: Ctx(Ctx), Enabled(Enabled) {}
296
297	void enterCondition(Sema &S, SourceLocation Tok);
298	void enterReturn(Sema &S, SourceLocation Tok);
299	void enterVariableInit(SourceLocation Tok, Decl *D);
300	/// Handles e.g. BaseType{ .D = Tok...
301	void enterDesignatedInitializer(SourceLocation Tok, QualType BaseType,
302	const Designation &D);
303	/// Computing a type for the function argument may require running
304	/// overloading, so we postpone its computation until it is actually needed.
305	///
306	/// Clients should be very careful when using this function, as it stores a
307	/// function_ref, clients should make sure all calls to get() with the same
308	/// location happen while function_ref is alive.
309	///
310	/// The callback should also emit signature help as a side-effect, but only
311	/// if the completion point has been reached.
312	void enterFunctionArgument(SourceLocation Tok,
313	llvm::function_ref<QualType()> ComputeType);
314
315	void enterParenExpr(SourceLocation Tok, SourceLocation LParLoc);
316	void enterUnary(Sema &S, SourceLocation Tok, tok::TokenKind OpKind,
317	SourceLocation OpLoc);
318	void enterBinary(Sema &S, SourceLocation Tok, Expr *LHS, tok::TokenKind Op);
319	void enterMemAccess(Sema &S, SourceLocation Tok, Expr *Base);
320	void enterSubscript(Sema &S, SourceLocation Tok, Expr *LHS);
321	/// Handles all type casts, including C-style cast, C++ casts, etc.
322	void enterTypeCast(SourceLocation Tok, QualType CastType);
323
324	/// Get the expected type associated with this location, if any.
325	///
326	/// If the location is a function argument, determining the expected type
327	/// involves considering all function overloads and the arguments so far.
328	/// In this case, signature help for these function overloads will be reported
329	/// as a side-effect (only if the completion point has been reached).
330	QualType get(SourceLocation Tok) const {
331	if (!Enabled \|\| Tok != ExpectedLoc)
332	return QualType ();
333	if (!Type.isNull())
334	return Type;
335	if (ComputeType)
336	return ComputeType ();
337	return QualType ();
338	}
339
340	private:
341	ASTContext *Ctx;
342	bool Enabled;
343	/// Start position of a token for which we store expected type.
344	SourceLocation ExpectedLoc;
345	/// Expected type for a token starting at ExpectedLoc.
346	QualType Type;
347	/// A function to compute expected type at ExpectedLoc. It is only considered
348	/// if Type is null.
349	llvm::function_ref<QualType()> ComputeType;
350	};
351
352	struct SkipBodyInfo {
353	SkipBodyInfo() = default;
354	bool ShouldSkip = false;
355	bool CheckSameAsPrevious = false;
356	NamedDecl Previous = nullptr*;
357	NamedDecl New = nullptr*;
358	};
359
360	/// Describes the result of template argument deduction.
361	///
362	/// The TemplateDeductionResult enumeration describes the result of
363	/// template argument deduction, as returned from
364	/// DeduceTemplateArguments(). The separate TemplateDeductionInfo
365	/// structure provides additional information about the results of
366	/// template argument deduction, e.g., the deduced template argument
367	/// list (if successful) or the specific template parameters or
368	/// deduced arguments that were involved in the failure.
369	enum class TemplateDeductionResult {
370	/// Template argument deduction was successful.
371	Success = `0`,
372	/// The declaration was invalid; do nothing.
373	Invalid,
374	/// Template argument deduction exceeded the maximum template
375	/// instantiation depth (which has already been diagnosed).
376	InstantiationDepth,
377	/// Template argument deduction did not deduce a value
378	/// for every template parameter.
379	Incomplete,
380	/// Template argument deduction did not deduce a value for every
381	/// expansion of an expanded template parameter pack.
382	IncompletePack,
383	/// Template argument deduction produced inconsistent
384	/// deduced values for the given template parameter.
385	Inconsistent,
386	/// Template argument deduction failed due to inconsistent
387	/// cv-qualifiers on a template parameter type that would
388	/// otherwise be deduced, e.g., we tried to deduce T in "const T"
389	/// but were given a non-const "X".
390	Underqualified,
391	/// Substitution of the deduced template argument values
392	/// resulted in an error.
393	SubstitutionFailure,
394	/// After substituting deduced template arguments, a dependent
395	/// parameter type did not match the corresponding argument.
396	DeducedMismatch,
397	/// After substituting deduced template arguments, an element of
398	/// a dependent parameter type did not match the corresponding element
399	/// of the corresponding argument (when deducing from an initializer list).
400	DeducedMismatchNested,
401	/// A non-depnedent component of the parameter did not match the
402	/// corresponding component of the argument.
403	NonDeducedMismatch,
404	/// When performing template argument deduction for a function
405	/// template, there were too many call arguments.
406	TooManyArguments,
407	/// When performing template argument deduction for a function
408	/// template, there were too few call arguments.
409	TooFewArguments,
410	/// The explicitly-specified template arguments were not valid
411	/// template arguments for the given template.
412	InvalidExplicitArguments,
413	/// Checking non-dependent argument conversions failed.
414	NonDependentConversionFailure,
415	/// The deduced arguments did not satisfy the constraints associated
416	/// with the template.
417	ConstraintsNotSatisfied,
418	/// Deduction failed; that's all we know.
419	MiscellaneousDeductionFailure,
420	/// CUDA Target attributes do not match.
421	CUDATargetMismatch,
422	/// Some error which was already diagnosed.
423	AlreadyDiagnosed
424	};
425
426	/// Kinds of C++ special members.
427	enum class CXXSpecialMemberKind {
428	DefaultConstructor,
429	CopyConstructor,
430	MoveConstructor,
431	CopyAssignment,
432	MoveAssignment,
433	Destructor,
434	Invalid
435	};
436
437	/// The kind of conversion being performed.
438	enum class CheckedConversionKind {
439	/// An implicit conversion.
440	Implicit,
441	/// A C-style cast.
442	CStyleCast,
443	/// A functional-style cast.
444	FunctionalCast,
445	/// A cast other than a C-style cast.
446	OtherCast,
447	/// A conversion for an operand of a builtin overloaded operator.
448	ForBuiltinOverloadedOp
449	};
450
451	enum class TagUseKind {
452	Reference, // Reference to a tag: 'struct foo X;'*
453	Declaration, // Fwd decl of a tag: 'struct foo;'
454	Definition, // Definition of a tag: 'struct foo { int X; } Y;'
455	Friend // Friend declaration: 'friend struct foo;'
456	};
457
458	/// Used with attributes/effects with a boolean condition, e.g. `nonblocking`.
459	enum class FunctionEffectMode : uint8_t {
460	None, // effect is not present.
461	False, // effect(false).
462	True, // effect(true).
463	Dependent // effect(expr) where expr is dependent.
464	};
465
466	/// pragma clang section kind
467	enum class PragmaClangSectionKind {
468	Invalid = `0`,
469	BSS = `1`,
470	Data = `2`,
471	Rodata = `3`,
472	Text = `4`,
473	Relro = `5`
474	};
475
476	enum class PragmaClangSectionAction { Set = `0`, Clear = `1` };
477
478	enum class PragmaOptionsAlignKind {
479	Native, // #pragma options align=native
480	Natural, // #pragma options align=natural
481	Packed, // #pragma options align=packed
482	Power, // #pragma options align=power
483	Mac68k, // #pragma options align=mac68k
484	Reset // #pragma options align=reset
485	};
486
487	enum class TUFragmentKind {
488	/// The global module fragment, between 'module;' and a module-declaration.
489	Global,
490	/// A normal translation unit fragment. For a non-module unit, this is the
491	/// entire translation unit. Otherwise, it runs from the module-declaration
492	/// to the private-module-fragment (if any) or the end of the TU (if not).
493	Normal,
494	/// The private module fragment, between 'module :private;' and the end of
495	/// the translation unit.
496	Private
497	};
498
499	enum class FormatStringType {
500	Scanf,
501	Printf,
502	NSString,
503	Strftime,
504	Strfmon,
505	Kprintf,
506	FreeBSDKPrintf,
507	OSTrace,
508	OSLog,
509	Unknown
510	};
511
512	// Used for emitting the right warning by DefaultVariadicArgumentPromotion
513	enum class VariadicCallType {
514	Function,
515	Block,
516	Method,
517	Constructor,
518	DoesNotApply
519	};
520
521	enum class BuiltinCountedByRefKind {
522	Assignment,
523	Initializer,
524	FunctionArg,
525	ReturnArg,
526	ArraySubscript,
527	BinaryExpr,
528	};
529
530	// Contexts where using non-trivial C union types can be disallowed. This is
531	// passed to err_non_trivial_c_union_in_invalid_context.
532	enum class NonTrivialCUnionContext {
533	// Function parameter.
534	FunctionParam,
535	// Function return.
536	FunctionReturn,
537	// Default-initialized object.
538	DefaultInitializedObject,
539	// Variable with automatic storage duration.
540	AutoVar,
541	// Initializer expression that might copy from another object.
542	CopyInit,
543	// Assignment.
544	Assignment,
545	// Compound literal.
546	CompoundLiteral,
547	// Block capture.
548	BlockCapture,
549	// lvalue-to-rvalue conversion of volatile type.
550	LValueToRValueVolatile,
551	};
552
553	/// Describes the result of the name lookup and resolution performed
554	/// by \c Sema::ClassifyName().
555	enum class NameClassificationKind {
556	/// This name is not a type or template in this context, but might be
557	/// something else.
558	Unknown,
559	/// Classification failed; an error has been produced.
560	Error,
561	/// The name has been typo-corrected to a keyword.
562	Keyword,
563	/// The name was classified as a type.
564	Type,
565	/// The name was classified as a specific non-type, non-template
566	/// declaration. ActOnNameClassifiedAsNonType should be called to
567	/// convert the declaration to an expression.
568	NonType,
569	/// The name was classified as an ADL-only function name.
570	/// ActOnNameClassifiedAsUndeclaredNonType should be called to convert the
571	/// result to an expression.
572	UndeclaredNonType,
573	/// The name denotes a member of a dependent type that could not be
574	/// resolved. ActOnNameClassifiedAsDependentNonType should be called to
575	/// convert the result to an expression.
576	DependentNonType,
577	/// The name was classified as an overload set, and an expression
578	/// representing that overload set has been formed.
579	/// ActOnNameClassifiedAsOverloadSet should be called to form a suitable
580	/// expression referencing the overload set.
581	OverloadSet,
582	/// The name was classified as a template whose specializations are types.
583	TypeTemplate,
584	/// The name was classified as a variable template name.
585	VarTemplate,
586	/// The name was classified as a function template name.
587	FunctionTemplate,
588	/// The name was classified as an ADL-only function template name.
589	UndeclaredTemplate,
590	/// The name was classified as a concept name.
591	Concept,
592	};
593
594	enum class PointerAuthDiscArgKind {
595	// Address discrimination argument of __ptrauth.
596	Addr,
597
598	// Extra discriminator argument of __ptrauth.
599	Extra,
600	};
601
602	/// Common ways to introduce type names without a tag for use in diagnostics.
603	/// Keep in sync with err_tag_reference_non_tag.
604	enum class NonTagKind {
605	NonStruct,
606	NonClass,
607	NonUnion,
608	NonEnum,
609	Typedef,
610	TypeAlias,
611	Template,
612	TypeAliasTemplate,
613	TemplateTemplateArgument,
614	};
615
616	enum class OffsetOfKind {
617	// Not parsing a type within __builtin_offsetof.
618	Outside,
619	// Parsing a type within __builtin_offsetof.
620	Builtin,
621	// Parsing a type within macro "offsetof", defined in __buitin_offsetof
622	// To improve our diagnostic message.
623	Macro,
624	};
625
626	/// Describes the kind of merge to perform for availability
627	/// attributes (including "deprecated", "unavailable", and "availability").
628	enum class AvailabilityMergeKind {
629	/// Don't merge availability attributes at all.
630	None,
631	/// Merge availability attributes for a redeclaration, which requires
632	/// an exact match.
633	Redeclaration,
634	/// Merge availability attributes for an override, which requires
635	/// an exact match or a weakening of constraints.
636	Override,
637	/// Merge availability attributes for an implementation of
638	/// a protocol requirement.
639	ProtocolImplementation,
640	/// Merge availability attributes for an implementation of
641	/// an optional protocol requirement.
642	OptionalProtocolImplementation
643	};
644
645	enum class TrivialABIHandling {
646	/// The triviality of a method unaffected by "trivial_abi".
647	IgnoreTrivialABI,
648
649	/// The triviality of a method affected by "trivial_abi".
650	ConsiderTrivialABI
651	};
652
653	enum class TryCaptureKind { Implicit, ExplicitByVal, ExplicitByRef };
654
655	enum class AllowFoldKind {
656	No,
657	Allow,
658	};
659
660	/// Context in which we're performing a usual arithmetic conversion.
661	enum class ArithConvKind {
662	/// An arithmetic operation.
663	Arithmetic,
664	/// A bitwise operation.
665	BitwiseOp,
666	/// A comparison.
667	Comparison,
668	/// A conditional (?:) operator.
669	Conditional,
670	/// A compound assignment expression.
671	CompAssign,
672	};
673
674	// Used for determining in which context a type is allowed to be passed to a
675	// vararg function.
676	enum class VarArgKind {
677	Valid,
678	ValidInCXX11,
679	Undefined,
680	MSVCUndefined,
681	Invalid
682	};
683
684	/// AssignConvertType - All of the 'assignment' semantic checks return this
685	/// enum to indicate whether the assignment was allowed. These checks are
686	/// done for simple assignments, as well as initialization, return from
687	/// function, argument passing, etc. The query is phrased in terms of a
688	/// source and destination type.
689	enum class AssignConvertType {
690	/// Compatible - the types are compatible according to the standard.
691	Compatible,
692
693	/// CompatibleVoidPtrToNonVoidPtr - The types are compatible in C because
694	/// a void can implicitly convert to another pointer type, which we*
695	/// differentiate for better diagnostic behavior.
696	CompatibleVoidPtrToNonVoidPtr,
697
698	/// PointerToInt - The assignment converts a pointer to an int, which we
699	/// accept as an extension.
700	PointerToInt,
701
702	/// IntToPointer - The assignment converts an int to a pointer, which we
703	/// accept as an extension.
704	IntToPointer,
705
706	/// FunctionVoidPointer - The assignment is between a function pointer and
707	/// void, which the standard doesn't allow, but we accept as an extension.*
708	FunctionVoidPointer,
709
710	/// IncompatiblePointer - The assignment is between two pointers types that
711	/// are not compatible, but we accept them as an extension.
712	IncompatiblePointer,
713
714	/// IncompatibleFunctionPointer - The assignment is between two function
715	/// pointers types that are not compatible, but we accept them as an
716	/// extension.
717	IncompatibleFunctionPointer,
718
719	/// IncompatibleFunctionPointerStrict - The assignment is between two
720	/// function pointer types that are not identical, but are compatible,
721	/// unless compiled with -fsanitize=cfi, in which case the type mismatch
722	/// may trip an indirect call runtime check.
723	IncompatibleFunctionPointerStrict,
724
725	/// IncompatiblePointerSign - The assignment is between two pointers types
726	/// which point to integers which have a different sign, but are otherwise
727	/// identical. This is a subset of the above, but broken out because it's by
728	/// far the most common case of incompatible pointers.
729	IncompatiblePointerSign,
730
731	/// CompatiblePointerDiscardsQualifiers - The assignment discards
732	/// c/v/r qualifiers, which we accept as an extension.
733	CompatiblePointerDiscardsQualifiers,
734
735	/// IncompatiblePointerDiscardsQualifiers - The assignment
736	/// discards qualifiers that we don't permit to be discarded,
737	/// like address spaces.
738	IncompatiblePointerDiscardsQualifiers,
739
740	/// IncompatiblePointerDiscardsOverflowBehavior - The assignment
741	/// discards overflow behavior annotations between otherwise compatible
742	/// pointer types.
743	IncompatiblePointerDiscardsOverflowBehavior,
744
745	/// IncompatibleNestedPointerAddressSpaceMismatch - The assignment
746	/// changes address spaces in nested pointer types which is not allowed.
747	/// For instance, converting __private int * to __generic int ** is*
748	/// illegal even though __private could be converted to __generic.
749	IncompatibleNestedPointerAddressSpaceMismatch,
750
751	/// IncompatibleNestedPointerQualifiers - The assignment is between two
752	/// nested pointer types, and the qualifiers other than the first two
753	/// levels differ e.g. char * -> const char *, but we accept them as an
754	/// extension.
755	IncompatibleNestedPointerQualifiers,
756
757	/// IncompatibleVectors - The assignment is between two vector types that
758	/// have the same size, which we accept as an extension.
759	IncompatibleVectors,
760
761	/// IntToBlockPointer - The assignment converts an int to a block
762	/// pointer. We disallow this.
763	IntToBlockPointer,
764
765	/// IncompatibleBlockPointer - The assignment is between two block
766	/// pointers types that are not compatible.
767	IncompatibleBlockPointer,
768
769	/// IncompatibleObjCQualifiedId - The assignment is between a qualified
770	/// id type and something else (that is incompatible with it). For example,
771	/// "id <XXX>" = "Foo ", where "Foo " doesn't implement the XXX protocol.
772	IncompatibleObjCQualifiedId,
773
774	/// IncompatibleObjCWeakRef - Assigning a weak-unavailable object to an
775	/// object with __weak qualifier.
776	IncompatibleObjCWeakRef,
777
778	/// IncompatibleOBTKinds - Assigning between incompatible OverflowBehaviorType
779	/// kinds, e.g., from __ob_trap to __ob_wrap or vice versa.
780	IncompatibleOBTKinds,
781
782	/// CompatibleOBTDiscards - Assignment discards overflow behavior
783	CompatibleOBTDiscards,
784
785	/// Incompatible - We reject this conversion outright, it is invalid to
786	/// represent it in the AST.
787	Incompatible
788	};
789
790	/// The scope in which to find allocation functions.
791	enum class AllocationFunctionScope {
792	/// Only look for allocation functions in the global scope.
793	Global,
794	/// Only look for allocation functions in the scope of the
795	/// allocated class.
796	Class,
797	/// Look for allocation functions in both the global scope
798	/// and in the scope of the allocated class.
799	Both
800	};
801
802	/// Describes the result of an "if-exists" condition check.
803	enum class IfExistsResult {
804	/// The symbol exists.
805	Exists,
806
807	/// The symbol does not exist.
808	DoesNotExist,
809
810	/// The name is a dependent name, so the results will differ
811	/// from one instantiation to the next.
812	Dependent,
813
814	/// An error occurred.
815	Error
816	};
817
818	enum class CorrectTypoKind {
819	NonError, // CorrectTypo used in a non error recovery situation.
820	ErrorRecovery // CorrectTypo used in normal error recovery.
821	};
822
823	enum class OverloadKind {
824	/// This is a legitimate overload: the existing declarations are
825	/// functions or function templates with different signatures.
826	Overload,
827
828	/// This is not an overload because the signature exactly matches
829	/// an existing declaration.
830	Match,
831
832	/// This is not an overload because the lookup results contain a
833	/// non-function.
834	NonFunction
835	};
836
837	/// Contexts in which a converted constant expression is required.
838	enum class CCEKind {
839	CaseValue, ///< Expression in a case label.
840	Enumerator, ///< Enumerator value with fixed underlying type.
841	TemplateArg, ///< Value of a non-type template parameter.
842	TempArgStrict, ///< As above, but applies strict template checking
843	///< rules.
844	ArrayBound, ///< Array bound in array declarator or new-expression.
845	ExplicitBool, ///< Condition in an explicit(bool) specifier.
846	Noexcept, ///< Condition in a noexcept(bool) specifier.
847	StaticAssertMessageSize, ///< Call to size() in a static assert
848	///< message.
849	StaticAssertMessageData, ///< Call to data() in a static assert
850	///< message.
851	};
852
853	/// Enums for the diagnostics of target, target_version and target_clones.
854	namespace DiagAttrParams {
855	enum DiagType { Unsupported, Duplicate, Unknown };
856	enum Specifier { None, CPU, Tune };
857	enum AttrName { Target, TargetClones, TargetVersion };
858	} // end namespace DiagAttrParams
859
860	void inferNoReturnAttr(Sema &S, Decl *D);
861
862	#ifdef __GNUC__
863	#pragma GCC diagnostic push
864	#pragma GCC diagnostic ignored "-Wattributes"
865	#endif
866	/// Sema - This implements semantic analysis and AST building for C.
867	/// \nosubgrouping
868	class Sema final : public SemaBase {
869	#ifdef __GNUC__
870	#pragma GCC diagnostic pop
871	#endif
872	// Table of Contents
873	// -----------------
874	// 1. Semantic Analysis (Sema.cpp)
875	// 2. API Notes (SemaAPINotes.cpp)
876	// 3. C++ Access Control (SemaAccess.cpp)
877	// 4. Attributes (SemaAttr.cpp)
878	// 5. Availability Attribute Handling (SemaAvailability.cpp)
879	// 6. Bounds Safety (SemaBoundsSafety.cpp)
880	// 7. Casts (SemaCast.cpp)
881	// 8. Extra Semantic Checking (SemaChecking.cpp)
882	// 9. C++ Coroutines (SemaCoroutine.cpp)
883	// 10. C++ Scope Specifiers (SemaCXXScopeSpec.cpp)
884	// 11. Declarations (SemaDecl.cpp)
885	// 12. Declaration Attribute Handling (SemaDeclAttr.cpp)
886	// 13. C++ Declarations (SemaDeclCXX.cpp)
887	// 14. C++ Exception Specifications (SemaExceptionSpec.cpp)
888	// 15. Expressions (SemaExpr.cpp)
889	// 16. C++ Expressions (SemaExprCXX.cpp)
890	// 17. Member Access Expressions (SemaExprMember.cpp)
891	// 18. Initializers (SemaInit.cpp)
892	// 19. C++ Lambda Expressions (SemaLambda.cpp)
893	// 20. Name Lookup (SemaLookup.cpp)
894	// 21. Modules (SemaModule.cpp)
895	// 22. C++ Overloading (SemaOverload.cpp)
896	// 23. Statements (SemaStmt.cpp)
897	// 24. `inline asm` Statement (SemaStmtAsm.cpp)
898	// 25. Statement Attribute Handling (SemaStmtAttr.cpp)
899	// 26. C++ Templates (SemaTemplate.cpp)
900	// 27. C++ Template Argument Deduction (SemaTemplateDeduction.cpp)
901	// 28. C++ Template Deduction Guide (SemaTemplateDeductionGuide.cpp)
902	// 29. C++ Template Instantiation (SemaTemplateInstantiate.cpp)
903	// 30. C++ Template Declaration Instantiation
904	// (SemaTemplateInstantiateDecl.cpp)
905	// 31. C++ Variadic Templates (SemaTemplateVariadic.cpp)
906	// 32. Constraints and Concepts (SemaConcept.cpp)
907	// 33. Types (SemaType.cpp)
908	// 34. FixIt Helpers (SemaFixItUtils.cpp)
909	// 35. Function Effects (SemaFunctionEffects.cpp)
910
911	/// \name Semantic Analysis
912	/// Implementations are in Sema.cpp
913	///@{
914
915	public:
916	Sema(Preprocessor &pp, ASTContext &ctxt, ASTConsumer &consumer,
917	TranslationUnitKind TUKind = TU_Complete,
918	CodeCompleteConsumer CompletionConsumer = nullptr*);
919	~Sema();
920
921	/// Perform initialization that occurs after the parser has been
922	/// initialized but before it parses anything.
923	void Initialize();
924
925	/// This virtual key function only exists to limit the emission of debug info
926	/// describing the Sema class. GCC and Clang only emit debug info for a class
927	/// with a vtable when the vtable is emitted. Sema is final and not
928	/// polymorphic, but the debug info size savings are so significant that it is
929	/// worth adding a vtable just to take advantage of this optimization.
930	LLVM_DECLARE_VIRTUAL_ANCHOR_FUNCTION();
931
932	const LangOptions &getLangOpts() const { return LangOpts; }
933	OpenCLOptions &getOpenCLOptions() { return OpenCLFeatures; }
934	FPOptions &getCurFPFeatures() { return CurFPFeatures; }
935
936	DiagnosticsEngine &getDiagnostics() const { return Diags; }
937	SourceManager &getSourceManager() const { return SourceMgr; }
938	Preprocessor &getPreprocessor() const { return PP; }
939	ASTContext &getASTContext() const { return Context; }
940	ASTConsumer &getASTConsumer() const { return Consumer; }
941	ASTMutationListener getASTMutationListener() const*;
942	ExternalSemaSource getExternalSource() const* { return ExternalSource.get(); }
943
944	DarwinSDKInfo *getDarwinSDKInfoForAvailabilityChecking(SourceLocation Loc,
945	StringRef Platform);
946	DarwinSDKInfo *getDarwinSDKInfoForAvailabilityChecking();
947
948	/// Registers an external source. If an external source already exists,
949	/// creates a multiplex external source and appends to it.
950	///
951	///\param[in] E - A non-null external sema source.
952	///
953	void addExternalSource(IntrusiveRefCntPtr<ExternalSemaSource> E);
954
955	/// Print out statistics about the semantic analysis.
956	void PrintStats() const;
957
958	/// Run some code with "sufficient" stack space. (Currently, at least 256K is
959	/// guaranteed). Produces a warning if we're low on stack space and allocates
960	/// more in that case. Use this in code that may recurse deeply (for example,
961	/// in template instantiation) to avoid stack overflow.
962	void runWithSufficientStackSpace(SourceLocation Loc,
963	llvm::function_ref<void()> Fn);
964
965	/// Returns default addr space for method qualifiers.
966	LangAS getDefaultCXXMethodAddrSpace() const;
967
968	/// Load weak undeclared identifiers from the external source.
969	void LoadExternalWeakUndeclaredIdentifiers();
970
971	/// Load #pragma redefine_extname'd undeclared identifiers from the external
972	/// source.
973	void LoadExternalExtnameUndeclaredIdentifiers();
974
975	/// Determine if VD, which must be a variable or function, is an external
976	/// symbol that nonetheless can't be referenced from outside this translation
977	/// unit because its type has no linkage and it's not extern "C".
978	bool isExternalWithNoLinkageType(const ValueDecl VD) const*;
979
980	/// Determines whether the given source location is in the main file
981	/// and we're in a context where we should warn about unused entities.
982	bool isMainFileLoc(SourceLocation Loc) const;
983
984	/// Obtain a sorted list of functions that are undefined but ODR-used.
985	void getUndefinedButUsed(
986	SmallVectorImpl<std::pair<NamedDecl *, SourceLocation>> &Undefined);
987
988	typedef std::pair<SourceLocation, bool> DeleteExprLoc;
989	typedef llvm::SmallVector<DeleteExprLoc, `4`> DeleteLocs;
990	/// Retrieves list of suspicious delete-expressions that will be checked at
991	/// the end of translation unit.
992	const llvm::MapVector<FieldDecl *, DeleteLocs> &
993	getMismatchingDeleteExpressions() const;
994
995	/// Cause the built diagnostic to be emitted on the DiagosticsEngine.
996	/// This is closely coupled to the SemaDiagnosticBuilder class and
997	/// should not be used elsewhere.
998	void EmitDiagnostic(unsigned DiagID, const DiagnosticBuilder &DB);
999
1000	void addImplicitTypedef(StringRef Name, QualType T);
1001
1002	/// Whether uncompilable error has occurred. This includes error happens
1003	/// in deferred diagnostics.
1004	bool hasUncompilableErrorOccurred() const;
1005
1006	/// Looks through the macro-expansion chain for the given
1007	/// location, looking for a macro expansion with the given name.
1008	/// If one is found, returns true and sets the location to that
1009	/// expansion loc.
1010	bool findMacroSpelling(SourceLocation &loc, StringRef name);
1011
1012	/// Calls \c Lexer::getLocForEndOfToken()
1013	SourceLocation getLocForEndOfToken(SourceLocation Loc, unsigned Offset = `0`);
1014
1015	/// Calls \c Lexer::findNextToken() to find the next token, and if the
1016	/// locations of both ends of the token can be resolved it return that
1017	/// range; Otherwise it returns an invalid SourceRange.
1018	SourceRange getRangeForNextToken(
1019	SourceLocation Loc, bool IncludeMacros, bool IncludeComments,
1020	std::optional<tok::TokenKind> ExpectedToken = std::nullopt);
1021
1022	/// Retrieve the module loader associated with the preprocessor.
1023	ModuleLoader &getModuleLoader() const;
1024
1025	/// Invent a new identifier for parameters of abbreviated templates.
1026	IdentifierInfo *
1027	InventAbbreviatedTemplateParameterTypeName(const IdentifierInfo *ParamName,
1028	unsigned Index);
1029
1030	void emitAndClearUnusedLocalTypedefWarnings();
1031
1032	// Emit all deferred diagnostics.
1033	void emitDeferredDiags();
1034
1035	/// This is called before the very first declaration in the translation unit
1036	/// is parsed. Note that the ASTContext may have already injected some
1037	/// declarations.
1038	void ActOnStartOfTranslationUnit();
1039	/// ActOnEndOfTranslationUnit - This is called at the very end of the
1040	/// translation unit when EOF is reached and all but the top-level scope is
1041	/// popped.
1042	void ActOnEndOfTranslationUnit();
1043	void ActOnEndOfTranslationUnitFragment(TUFragmentKind Kind);
1044
1045	/// Determines the active Scope associated with the given declaration
1046	/// context.
1047	///
1048	/// This routine maps a declaration context to the active Scope object that
1049	/// represents that declaration context in the parser. It is typically used
1050	/// from "scope-less" code (e.g., template instantiation, lazy creation of
1051	/// declarations) that injects a name for name-lookup purposes and, therefore,
1052	/// must update the Scope.
1053	///
1054	/// \returns The scope corresponding to the given declaraion context, or NULL
1055	/// if no such scope is open.
1056	Scope getScopeForContext(DeclContext Ctx);
1057
1058	void PushFunctionScope();
1059	void PushBlockScope(Scope BlockScope, BlockDecl Block);
1060	sema::LambdaScopeInfo *PushLambdaScope();
1061
1062	/// This is used to inform Sema what the current TemplateParameterDepth
1063	/// is during Parsing. Currently it is used to pass on the depth
1064	/// when parsing generic lambda 'auto' parameters.
1065	void RecordParsingTemplateParameterDepth(unsigned Depth);
1066
1067	void PushCapturedRegionScope(Scope RegionScope, CapturedDecl CD,
1068	RecordDecl *RD, CapturedRegionKind K,
1069	unsigned OpenMPCaptureLevel = `0`);
1070
1071	/// Custom deleter to allow FunctionScopeInfos to be kept alive for a short
1072	/// time after they've been popped.
1073	class PoppedFunctionScopeDeleter {
1074	Sema *Self;
1075
1076	public:
1077	explicit PoppedFunctionScopeDeleter(Sema *Self) : Self(Self) {}
1078	void operator()(sema::FunctionScopeInfo Scope) const*;
1079	};
1080
1081	using PoppedFunctionScopePtr =
1082	std::unique_ptr<sema::FunctionScopeInfo, PoppedFunctionScopeDeleter>;
1083
1084	/// Pop a function (or block or lambda or captured region) scope from the
1085	/// stack.
1086	///
1087	/// \param WP The warning policy to use for CFG-based warnings, or null if
1088	/// such warnings should not be produced.
1089	/// \param D The declaration corresponding to this function scope, if
1090	/// producing CFG-based warnings.
1091	/// \param BlockType The type of the block expression, if D is a BlockDecl.
1092	PoppedFunctionScopePtr
1093	PopFunctionScopeInfo(const sema::AnalysisBasedWarnings::Policy WP = nullptr*,
1094	Decl D = nullptr*, QualType BlockType = QualType ());
1095
1096	sema::FunctionScopeInfo getEnclosingFunction() const*;
1097
1098	void setFunctionHasBranchIntoScope();
1099	void setFunctionHasBranchProtectedScope();
1100	void setFunctionHasIndirectGoto();
1101	void setFunctionHasMustTail();
1102
1103	void PushCompoundScope(bool IsStmtExpr);
1104	void PopCompoundScope();
1105
1106	/// Determine whether any errors occurred within this function/method/
1107	/// block.
1108	bool hasAnyUnrecoverableErrorsInThisFunction() const;
1109
1110	/// Retrieve the current block, if any.
1111	sema::BlockScopeInfo *getCurBlock();
1112
1113	/// Get the innermost lambda or block enclosing the current location, if any.
1114	/// This looks through intervening non-lambda, non-block scopes such as local
1115	/// functions.
1116	sema::CapturingScopeInfo getEnclosingLambdaOrBlock() const*;
1117
1118	/// Retrieve the current lambda scope info, if any.
1119	/// \param IgnoreNonLambdaCapturingScope true if should find the top-most
1120	/// lambda scope info ignoring all inner capturing scopes that are not
1121	/// lambda scopes.
1122	sema::LambdaScopeInfo *
1123	getCurLambda(bool IgnoreNonLambdaCapturingScope = false);
1124
1125	/// Retrieve the current generic lambda info, if any.
1126	sema::LambdaScopeInfo *getCurGenericLambda();
1127
1128	/// Retrieve the current captured region, if any.
1129	sema::CapturedRegionScopeInfo *getCurCapturedRegion();
1130
1131	void ActOnComment(SourceRange Comment);
1132
1133	/// Retrieve the parser's current scope.
1134	///
1135	/// This routine must only be used when it is certain that semantic analysis
1136	/// and the parser are in precisely the same context, which is not the case
1137	/// when, e.g., we are performing any kind of template instantiation.
1138	/// Therefore, the only safe places to use this scope are in the parser
1139	/// itself and in routines directly invoked from the parser and never* from*
1140	/// template substitution or instantiation.
1141	Scope getCurScope() const* { return CurScope; }
1142
1143	IdentifierInfo getSuperIdentifier() const*;
1144
1145	DeclContext getCurLexicalContext() const* {
1146	return OriginalLexicalContext ? OriginalLexicalContext : CurContext;
1147	}
1148
1149	SemaDiagnosticBuilder targetDiag(SourceLocation Loc, unsigned DiagID,
1150	const FunctionDecl FD = nullptr*);
1151	SemaDiagnosticBuilder targetDiag(SourceLocation Loc,
1152	const PartialDiagnostic &PD,
1153	const FunctionDecl FD = nullptr*) {
1154	return targetDiag(Loc, DiagID: PD.getDiagID(), FD) << PD;
1155	}
1156
1157	/// Check if the type is allowed to be used for the current target.
1158	void checkTypeSupport(QualType Ty, SourceLocation Loc,
1159	ValueDecl D = nullptr*);
1160
1161	/// ImpCastExprToType - If Expr is not of type 'Type', insert an implicit
1162	/// cast. If there is already an implicit cast, merge into the existing one.
1163	/// If isLvalue, the result of the cast is an lvalue.
1164	ExprResult ImpCastExprToType(
1165	Expr *E, QualType Type, CastKind CK, ExprValueKind VK = VK_PRValue,
1166	const CXXCastPath BasePath = nullptr*,
1167	CheckedConversionKind CCK = CheckedConversionKind::Implicit);
1168
1169	/// ScalarTypeToBooleanCastKind - Returns the cast kind corresponding
1170	/// to the conversion from scalar type ScalarTy to the Boolean type.
1171	static CastKind ScalarTypeToBooleanCastKind(QualType ScalarTy);
1172
1173	/// If \p AllowLambda is true, treat lambda as function.
1174	DeclContext getFunctionLevelDeclContext(bool* AllowLambda = false) const;
1175
1176	/// Returns a pointer to the innermost enclosing function, or nullptr if the
1177	/// current context is not inside a function. If \p AllowLambda is true,
1178	/// this can return the call operator of an enclosing lambda, otherwise
1179	/// lambdas are skipped when looking for an enclosing function.
1180	FunctionDecl getCurFunctionDecl(bool* AllowLambda = false) const;
1181
1182	/// getCurMethodDecl - If inside of a method body, this returns a pointer to
1183	/// the method decl for the method being parsed. If we're currently
1184	/// in a 'block', this returns the containing context.
1185	ObjCMethodDecl *getCurMethodDecl();
1186
1187	/// getCurFunctionOrMethodDecl - Return the Decl for the current ObjC method
1188	/// or C function we're in, otherwise return null. If we're currently
1189	/// in a 'block', this returns the containing context.
1190	NamedDecl getCurFunctionOrMethodDecl() const*;
1191
1192	/// Warn if we're implicitly casting from a _Nullable pointer type to a
1193	/// _Nonnull one.
1194	void diagnoseNullableToNonnullConversion(QualType DstType, QualType SrcType,
1195	SourceLocation Loc);
1196
1197	/// Warn when implicitly casting 0 to nullptr.
1198	void diagnoseZeroToNullptrConversion(CastKind Kind, const Expr *E);
1199
1200	/// Warn when implicitly changing function effects.
1201	void diagnoseFunctionEffectConversion(QualType DstType, QualType SrcType,
1202	SourceLocation Loc);
1203
1204	/// makeUnavailableInSystemHeader - There is an error in the current
1205	/// context. If we're still in a system header, and we can plausibly
1206	/// make the relevant declaration unavailable instead of erroring, do
1207	/// so and return true.
1208	bool makeUnavailableInSystemHeader(SourceLocation loc,
1209	UnavailableAttr::ImplicitReason reason);
1210
1211	/// Retrieve a suitable printing policy for diagnostics.
1212	PrintingPolicy getPrintingPolicy() const {
1213	return getPrintingPolicy(Ctx: Context, PP);
1214	}
1215
1216	/// Retrieve a suitable printing policy for diagnostics.
1217	static PrintingPolicy getPrintingPolicy(const ASTContext &Ctx,
1218	const Preprocessor &PP);
1219
1220	/// Scope actions.
1221	void ActOnTranslationUnitScope(Scope *S);
1222
1223	/// Determine whether \param D is function like (function or function
1224	/// template) for parsing.
1225	bool isDeclaratorFunctionLike(Declarator &D);
1226
1227	/// The maximum alignment, same as in llvm::Value. We duplicate them here
1228	/// because that allows us not to duplicate the constants in clang code,
1229	/// which we must to since we can't directly use the llvm constants.
1230	/// The value is verified against llvm here: lib/CodeGen/CGDecl.cpp
1231	///
1232	/// This is the greatest alignment value supported by load, store, and alloca
1233	/// instructions, and global values.
1234	static const unsigned MaxAlignmentExponent = `32`;
1235	static const uint64_t MaximumAlignment = `1ull` << MaxAlignmentExponent;
1236
1237	/// Flag indicating whether or not to collect detailed statistics.
1238	bool CollectStats;
1239
1240	std::unique_ptr<sema::FunctionScopeInfo> CachedFunctionScope;
1241
1242	/// Stack containing information about each of the nested
1243	/// function, block, and method scopes that are currently active.
1244	SmallVector<sema::FunctionScopeInfo *, `4`> FunctionScopes;
1245
1246	/// The index of the first FunctionScope that corresponds to the current
1247	/// context.
1248	unsigned FunctionScopesStart = `0`;
1249
1250	/// Track the number of currently active capturing scopes.
1251	unsigned CapturingFunctionScopes = `0`;
1252
1253	llvm::BumpPtrAllocator BumpAlloc;
1254
1255	/// The kind of translation unit we are processing.
1256	///
1257	/// When we're processing a complete translation unit, Sema will perform
1258	/// end-of-translation-unit semantic tasks (such as creating
1259	/// initializers for tentative definitions in C) once parsing has
1260	/// completed. Modules and precompiled headers perform different kinds of
1261	/// checks.
1262	const TranslationUnitKind TUKind;
1263
1264	/// Translation Unit Scope - useful to Objective-C actions that need
1265	/// to lookup file scope declarations in the "ordinary" C decl namespace.
1266	/// For example, user-defined classes, built-in "id" type, etc.
1267	Scope *TUScope;
1268
1269	void incrementMSManglingNumber() const {
1270	return CurScope->incrementMSManglingNumber();
1271	}
1272
1273	/// Try to recover by turning the given expression into a
1274	/// call. Returns true if recovery was attempted or an error was
1275	/// emitted; this may also leave the ExprResult invalid.
1276	bool tryToRecoverWithCall(ExprResult &E, const PartialDiagnostic &PD,
1277	bool ForceComplain = false,
1278	bool (IsPlausibleResult)(QualType) = nullptr*);
1279
1280	// Adds implicit lifetime bound attribute for implicit this to its
1281	// TypeSourceInfo.
1282	void addLifetimeBoundToImplicitThis(CXXMethodDecl *MD);
1283
1284	/// Figure out if an expression could be turned into a call.
1285	///
1286	/// Use this when trying to recover from an error where the programmer may
1287	/// have written just the name of a function instead of actually calling it.
1288	///
1289	/// \param E - The expression to examine.
1290	/// \param ZeroArgCallReturnTy - If the expression can be turned into a call
1291	/// with no arguments, this parameter is set to the type returned by such a
1292	/// call; otherwise, it is set to an empty QualType.
1293	/// \param OverloadSet - If the expression is an overloaded function
1294	/// name, this parameter is populated with the decls of the various
1295	/// overloads.
1296	bool tryExprAsCall(Expr &E, QualType &ZeroArgCallReturnTy,
1297	UnresolvedSetImpl &NonTemplateOverloads);
1298
1299	typedef OpaquePtr<DeclGroupRef> DeclGroupPtrTy;
1300	typedef OpaquePtr<TemplateName> TemplateTy;
1301	typedef OpaquePtr<QualType> TypeTy;
1302
1303	OpenCLOptions OpenCLFeatures;
1304	FPOptions CurFPFeatures;
1305
1306	const LangOptions &LangOpts;
1307	Preprocessor &PP;
1308	ASTContext &Context;
1309	ASTConsumer &Consumer;
1310	DiagnosticsEngine &Diags;
1311	SourceManager &SourceMgr;
1312	api_notes::APINotesManager APINotes;
1313
1314	/// A RAII object to enter scope of a compound statement.
1315	class CompoundScopeRAII {
1316	public:
1317	CompoundScopeRAII(Sema &S, bool IsStmtExpr = false) : S(S) {
1318	S.ActOnStartOfCompoundStmt(IsStmtExpr);
1319	}
1320
1321	~CompoundScopeRAII() { S.ActOnFinishOfCompoundStmt(); }
1322	CompoundScopeRAII(const CompoundScopeRAII &) = delete;
1323	CompoundScopeRAII &operator=(const CompoundScopeRAII &) = delete;
1324
1325	private:
1326	Sema &S;
1327	};
1328
1329	/// An RAII helper that pops function a function scope on exit.
1330	struct FunctionScopeRAII {
1331	Sema &S;
1332	bool Active;
1333	FunctionScopeRAII(Sema &S) : S(S), Active(true) {}
1334	~FunctionScopeRAII() {
1335	if (Active)
1336	S.PopFunctionScopeInfo();
1337	}
1338	void disable() { Active = false; }
1339	};
1340
1341	sema::FunctionScopeInfo getCurFunction() const* {
1342	return FunctionScopes.empty() ? nullptr : FunctionScopes.back();
1343	}
1344
1345	/// Worker object for performing CFG-based warnings.
1346	sema::AnalysisBasedWarnings AnalysisWarnings;
1347	threadSafety::BeforeSet *ThreadSafetyDeclCache;
1348
1349	/// Callback to the parser to parse templated functions when needed.
1350	typedef void LateTemplateParserCB(void *P, LateParsedTemplate &LPT);
1351	LateTemplateParserCB *LateTemplateParser;
1352	void *OpaqueParser;
1353
1354	void SetLateTemplateParser(LateTemplateParserCB LTP, void* *P) {
1355	LateTemplateParser = LTP;
1356	OpaqueParser = P;
1357	}
1358
1359	/// Callback to the parser to parse a type expressed as a string.
1360	std::function<TypeResult(StringRef, StringRef, SourceLocation)>
1361	ParseTypeFromStringCallback;
1362
1363	/// VAListTagName - The declaration name corresponding to __va_list_tag.
1364	/// This is used as part of a hack to omit that class from ADL results.
1365	DeclarationName VAListTagName;
1366
1367	/// Is the last error level diagnostic immediate. This is used to determined
1368	/// whether the next info diagnostic should be immediate.
1369	bool IsLastErrorImmediate = true;
1370
1371	/// Track if we're currently analyzing overflow behavior types in assignment
1372	/// context.
1373	bool InOverflowBehaviorAssignmentContext = false;
1374
1375	class DelayedDiagnostics;
1376
1377	class DelayedDiagnosticsState {
1378	sema::DelayedDiagnosticPool SavedPool = nullptr*;
1379	friend class Sema::DelayedDiagnostics;
1380	};
1381	typedef DelayedDiagnosticsState ParsingDeclState;
1382	typedef DelayedDiagnosticsState ProcessingContextState;
1383
1384	/// A class which encapsulates the logic for delaying diagnostics
1385	/// during parsing and other processing.
1386	class DelayedDiagnostics {
1387	/// The current pool of diagnostics into which delayed
1388	/// diagnostics should go.
1389	sema::DelayedDiagnosticPool CurPool = nullptr*;
1390
1391	public:
1392	DelayedDiagnostics() = default;
1393
1394	/// Adds a delayed diagnostic.
1395	void add(const sema::DelayedDiagnostic &diag); // in DelayedDiagnostic.h
1396
1397	/// Determines whether diagnostics should be delayed.
1398	bool shouldDelayDiagnostics() { return CurPool != nullptr; }
1399
1400	/// Returns the current delayed-diagnostics pool.
1401	sema::DelayedDiagnosticPool getCurrentPool() const* { return CurPool; }
1402
1403	/// Enter a new scope. Access and deprecation diagnostics will be
1404	/// collected in this pool.
1405	DelayedDiagnosticsState push(sema::DelayedDiagnosticPool &pool) {
1406	DelayedDiagnosticsState state;
1407	state.SavedPool = CurPool;
1408	CurPool = &pool;
1409	return state;
1410	}
1411
1412	/// Leave a delayed-diagnostic state that was previously pushed.
1413	/// Do not emit any of the diagnostics. This is performed as part
1414	/// of the bookkeeping of popping a pool "properly".
1415	void popWithoutEmitting(DelayedDiagnosticsState state) {
1416	CurPool = state.SavedPool;
1417	}
1418
1419	/// Enter a new scope where access and deprecation diagnostics are
1420	/// not delayed.
1421	DelayedDiagnosticsState pushUndelayed() {
1422	DelayedDiagnosticsState state;
1423	state.SavedPool = CurPool;
1424	CurPool = nullptr;
1425	return state;
1426	}
1427
1428	/// Undo a previous pushUndelayed().
1429	void popUndelayed(DelayedDiagnosticsState state) {
1430	assert(CurPool == nullptr);
1431	CurPool = state.SavedPool;
1432	}
1433	} DelayedDiagnostics;
1434
1435	ParsingDeclState PushParsingDeclaration(sema::DelayedDiagnosticPool &pool) {
1436	return DelayedDiagnostics.push(pool);
1437	}
1438
1439	/// Diagnostics that are emitted only if we discover that the given function
1440	/// must be codegen'ed. Because handling these correctly adds overhead to
1441	/// compilation, this is currently only used for offload languages like CUDA,
1442	/// OpenMP, and SYCL.
1443	SemaDiagnosticBuilder::DeferredDiagnosticsType DeviceDeferredDiags;
1444
1445	/// CurContext - This is the current declaration context of parsing.
1446	DeclContext *CurContext;
1447
1448	SemaAMDGPU &AMDGPU() {
1449	assert(AMDGPUPtr);
1450	return *AMDGPUPtr;
1451	}
1452
1453	SemaARM &ARM() {
1454	assert(ARMPtr);
1455	return *ARMPtr;
1456	}
1457
1458	SemaAVR &AVR() {
1459	assert(AVRPtr);
1460	return *AVRPtr;
1461	}
1462
1463	SemaBPF &BPF() {
1464	assert(BPFPtr);
1465	return *BPFPtr;
1466	}
1467
1468	SemaCodeCompletion &CodeCompletion() {
1469	assert(CodeCompletionPtr);
1470	return *CodeCompletionPtr;
1471	}
1472
1473	SemaCUDA &CUDA() {
1474	assert(CUDAPtr);
1475	return *CUDAPtr;
1476	}
1477
1478	SemaDirectX &DirectX() {
1479	assert(DirectXPtr);
1480	return *DirectXPtr;
1481	}
1482
1483	SemaHLSL &HLSL() {
1484	assert(HLSLPtr);
1485	return *HLSLPtr;
1486	}
1487
1488	SemaHexagon &Hexagon() {
1489	assert(HexagonPtr);
1490	return *HexagonPtr;
1491	}
1492
1493	SemaLoongArch &LoongArch() {
1494	assert(LoongArchPtr);
1495	return *LoongArchPtr;
1496	}
1497
1498	SemaM68k &M68k() {
1499	assert(M68kPtr);
1500	return *M68kPtr;
1501	}
1502
1503	SemaMIPS &MIPS() {
1504	assert(MIPSPtr);
1505	return *MIPSPtr;
1506	}
1507
1508	SemaMSP430 &MSP430() {
1509	assert(MSP430Ptr);
1510	return *MSP430Ptr;
1511	}
1512
1513	SemaNVPTX &NVPTX() {
1514	assert(NVPTXPtr);
1515	return *NVPTXPtr;
1516	}
1517
1518	SemaObjC &ObjC() {
1519	assert(ObjCPtr);
1520	return *ObjCPtr;
1521	}
1522
1523	SemaOpenACC &OpenACC() {
1524	assert(OpenACCPtr);
1525	return *OpenACCPtr;
1526	}
1527
1528	SemaOpenCL &OpenCL() {
1529	assert(OpenCLPtr);
1530	return *OpenCLPtr;
1531	}
1532
1533	SemaOpenMP &OpenMP() {
1534	assert(OpenMPPtr && "SemaOpenMP is dead");
1535	return *OpenMPPtr;
1536	}
1537
1538	SemaPPC &PPC() {
1539	assert(PPCPtr);
1540	return *PPCPtr;
1541	}
1542
1543	SemaPseudoObject &PseudoObject() {
1544	assert(PseudoObjectPtr);
1545	return *PseudoObjectPtr;
1546	}
1547
1548	SemaRISCV &RISCV() {
1549	assert(RISCVPtr);
1550	return *RISCVPtr;
1551	}
1552
1553	SemaSPIRV &SPIRV() {
1554	assert(SPIRVPtr);
1555	return *SPIRVPtr;
1556	}
1557
1558	SemaSYCL &SYCL() {
1559	assert(SYCLPtr);
1560	return *SYCLPtr;
1561	}
1562
1563	SemaSwift &Swift() {
1564	assert(SwiftPtr);
1565	return *SwiftPtr;
1566	}
1567
1568	SemaSystemZ &SystemZ() {
1569	assert(SystemZPtr);
1570	return *SystemZPtr;
1571	}
1572
1573	SemaWasm &Wasm() {
1574	assert(WasmPtr);
1575	return *WasmPtr;
1576	}
1577
1578	SemaX86 &X86() {
1579	assert(X86Ptr);
1580	return *X86Ptr;
1581	}
1582
1583	/// Source of additional semantic information.
1584	IntrusiveRefCntPtr<ExternalSemaSource> ExternalSource;
1585
1586	protected:
1587	friend class Parser;
1588	friend class InitializationSequence;
1589	friend class ASTReader;
1590	friend class ASTDeclReader;
1591	friend class ASTWriter;
1592
1593	private:
1594	std::optional<std::unique_ptr<DarwinSDKInfo>> CachedDarwinSDKInfo;
1595	bool WarnedDarwinSDKInfoMissing = false;
1596
1597	StackExhaustionHandler StackHandler;
1598
1599	Sema(const Sema &) = delete;
1600	void operator=(const Sema &) = delete;
1601
1602	/// The handler for the FileChanged preprocessor events.
1603	///
1604	/// Used for diagnostics that implement custom semantic analysis for #include
1605	/// directives, like -Wpragma-pack.
1606	sema::SemaPPCallbacks *SemaPPCallbackHandler;
1607
1608	/// The parser's current scope.
1609	///
1610	/// The parser maintains this state here.
1611	Scope *CurScope;
1612
1613	mutable IdentifierInfo *Ident_super;
1614
1615	std::unique_ptr<SemaAMDGPU> AMDGPUPtr;
1616	std::unique_ptr<SemaARM> ARMPtr;
1617	std::unique_ptr<SemaAVR> AVRPtr;
1618	std::unique_ptr<SemaBPF> BPFPtr;
1619	std::unique_ptr<SemaCodeCompletion> CodeCompletionPtr;
1620	std::unique_ptr<SemaCUDA> CUDAPtr;
1621	std::unique_ptr<SemaDirectX> DirectXPtr;
1622	std::unique_ptr<SemaHLSL> HLSLPtr;
1623	std::unique_ptr<SemaHexagon> HexagonPtr;
1624	std::unique_ptr<SemaLoongArch> LoongArchPtr;
1625	std::unique_ptr<SemaM68k> M68kPtr;
1626	std::unique_ptr<SemaMIPS> MIPSPtr;
1627	std::unique_ptr<SemaMSP430> MSP430Ptr;
1628	std::unique_ptr<SemaNVPTX> NVPTXPtr;
1629	std::unique_ptr<SemaObjC> ObjCPtr;
1630	std::unique_ptr<SemaOpenACC> OpenACCPtr;
1631	std::unique_ptr<SemaOpenCL> OpenCLPtr;
1632	std::unique_ptr<SemaOpenMP> OpenMPPtr;
1633	std::unique_ptr<SemaPPC> PPCPtr;
1634	std::unique_ptr<SemaPseudoObject> PseudoObjectPtr;
1635	std::unique_ptr<SemaRISCV> RISCVPtr;
1636	std::unique_ptr<SemaSPIRV> SPIRVPtr;
1637	std::unique_ptr<SemaSYCL> SYCLPtr;
1638	std::unique_ptr<SemaSwift> SwiftPtr;
1639	std::unique_ptr<SemaSystemZ> SystemZPtr;
1640	std::unique_ptr<SemaWasm> WasmPtr;
1641	std::unique_ptr<SemaX86> X86Ptr;
1642
1643	///@}
1644
1645	//
1646	//
1647	// -------------------------------------------------------------------------
1648	//
1649	//
1650
1651	/// \name API Notes
1652	/// Implementations are in SemaAPINotes.cpp
1653	///@{
1654
1655	public:
1656	/// Map any API notes provided for this declaration to attributes on the
1657	/// declaration.
1658	///
1659	/// Triggered by declaration-attribute processing.
1660	void ProcessAPINotes(Decl *D);
1661	/// Apply the 'Nullability:' annotation to the specified declaration
1662	void ApplyNullability(Decl *D, NullabilityKind Nullability);
1663	/// Apply the 'Type:' annotation to the specified declaration
1664	void ApplyAPINotesType(Decl *D, StringRef TypeString);
1665
1666	/// Whether APINotes should be gathered for all applicable Swift language
1667	/// versions, without being applied. Leaving clients of the current module
1668	/// to select and apply the correct version.
1669	bool captureSwiftVersionIndependentAPINotes() {
1670	return APINotes.captureVersionIndependentSwift();
1671	}
1672	///@}
1673
1674	//
1675	//
1676	// -------------------------------------------------------------------------
1677	//
1678	//
1679
1680	/// \name C++ Access Control
1681	/// Implementations are in SemaAccess.cpp
1682	///@{
1683
1684	public:
1685	enum AccessResult {
1686	AR_accessible,
1687	AR_inaccessible,
1688	AR_dependent,
1689	AR_delayed
1690	};
1691
1692	/// SetMemberAccessSpecifier - Set the access specifier of a member.
1693	/// Returns true on error (when the previous member decl access specifier
1694	/// is different from the new member decl access specifier).
1695	bool SetMemberAccessSpecifier(NamedDecl *MemberDecl,
1696	NamedDecl *PrevMemberDecl,
1697	AccessSpecifier LexicalAS);
1698
1699	/// Perform access-control checking on a previously-unresolved member
1700	/// access which has now been resolved to a member.
1701	AccessResult CheckUnresolvedMemberAccess(UnresolvedMemberExpr *E,
1702	DeclAccessPair FoundDecl);
1703	AccessResult CheckUnresolvedLookupAccess(UnresolvedLookupExpr *E,
1704	DeclAccessPair FoundDecl);
1705
1706	/// Checks access to an overloaded operator new or delete.
1707	AccessResult CheckAllocationAccess(SourceLocation OperatorLoc,
1708	SourceRange PlacementRange,
1709	CXXRecordDecl *NamingClass,
1710	DeclAccessPair FoundDecl,
1711	bool Diagnose = true);
1712
1713	/// Checks access to a constructor.
1714	AccessResult CheckConstructorAccess(SourceLocation Loc, CXXConstructorDecl *D,
1715	DeclAccessPair FoundDecl,
1716	const InitializedEntity &Entity,
1717	bool IsCopyBindingRefToTemp = false);
1718
1719	/// Checks access to a constructor.
1720	AccessResult CheckConstructorAccess(SourceLocation Loc, CXXConstructorDecl *D,
1721	DeclAccessPair FoundDecl,
1722	const InitializedEntity &Entity,
1723	const PartialDiagnostic &PDiag);
1724	AccessResult CheckDestructorAccess(SourceLocation Loc,
1725	CXXDestructorDecl *Dtor,
1726	const PartialDiagnostic &PDiag,
1727	QualType objectType = QualType ());
1728
1729	/// Checks access to the target of a friend declaration.
1730	AccessResult CheckFriendAccess(NamedDecl *D);
1731
1732	/// Checks access to a member.
1733	AccessResult CheckMemberAccess(SourceLocation UseLoc,
1734	CXXRecordDecl *NamingClass,
1735	DeclAccessPair Found);
1736
1737	/// Checks implicit access to a member in a structured binding.
1738	AccessResult
1739	CheckStructuredBindingMemberAccess(SourceLocation UseLoc,
1740	CXXRecordDecl *DecomposedClass,
1741	DeclAccessPair Field);
1742	AccessResult CheckMemberOperatorAccess(SourceLocation Loc, Expr *ObjectExpr,
1743	const SourceRange &,
1744	DeclAccessPair FoundDecl);
1745
1746	/// Checks access to an overloaded member operator, including
1747	/// conversion operators.
1748	AccessResult CheckMemberOperatorAccess(SourceLocation Loc, Expr *ObjectExpr,
1749	Expr *ArgExpr,
1750	DeclAccessPair FoundDecl);
1751	AccessResult CheckMemberOperatorAccess(SourceLocation Loc, Expr *ObjectExpr,
1752	ArrayRef<Expr *> ArgExprs,
1753	DeclAccessPair FoundDecl);
1754	AccessResult CheckAddressOfMemberAccess(Expr *OvlExpr,
1755	DeclAccessPair FoundDecl);
1756
1757	/// Checks access for a hierarchy conversion.
1758	///
1759	/// \param ForceCheck true if this check should be performed even if access
1760	/// control is disabled; some things rely on this for semantics
1761	/// \param ForceUnprivileged true if this check should proceed as if the
1762	/// context had no special privileges
1763	AccessResult CheckBaseClassAccess(SourceLocation AccessLoc, QualType Base,
1764	QualType Derived, const CXXBasePath &Path,
1765	unsigned DiagID, bool ForceCheck = false,
1766	bool ForceUnprivileged = false);
1767
1768	AccessResult CheckBaseClassAccess(
1769	SourceLocation AccessLoc, CXXRecordDecl Base, CXXRecordDecl Derived,
1770	const CXXBasePath &Path, unsigned DiagID,
1771	llvm::function_ref<void(PartialDiagnostic &PD)> SetupPDiag,
1772	bool ForceCheck = false, bool ForceUnprivileged = false);
1773
1774	/// Checks access to all the declarations in the given result set.
1775	void CheckLookupAccess(const LookupResult &R);
1776
1777	/// Checks access to Target from the given class. The check will take access
1778	/// specifiers into account, but no member access expressions and such.
1779	///
1780	/// \param Target the declaration to check if it can be accessed
1781	/// \param NamingClass the class in which the lookup was started.
1782	/// \param BaseType type of the left side of member access expression.
1783	/// \p BaseType and \p NamingClass are used for C++ access control.
1784	/// Depending on the lookup case, they should be set to the following:
1785	/// - lhs.target (member access without a qualifier):
1786	/// \p BaseType and \p NamingClass are both the type of 'lhs'.
1787	/// - lhs.X::target (member access with a qualifier):
1788	/// BaseType is the type of 'lhs', NamingClass is 'X'
1789	/// - X::target (qualified lookup without member access):
1790	/// BaseType is null, NamingClass is 'X'.
1791	/// - target (unqualified lookup).
1792	/// BaseType is null, NamingClass is the parent class of 'target'.
1793	/// \return true if the Target is accessible from the Class, false otherwise.
1794	bool IsSimplyAccessible(NamedDecl Decl, CXXRecordDecl NamingClass,
1795	QualType BaseType);
1796
1797	/// Is the given member accessible for the purposes of deciding whether to
1798	/// define a special member function as deleted?
1799	bool isMemberAccessibleForDeletion(CXXRecordDecl *NamingClass,
1800	DeclAccessPair Found, QualType ObjectType,
1801	SourceLocation Loc,
1802	const PartialDiagnostic &Diag);
1803	bool isMemberAccessibleForDeletion(CXXRecordDecl *NamingClass,
1804	DeclAccessPair Found,
1805	QualType ObjectType) {
1806	return isMemberAccessibleForDeletion(NamingClass, Found, ObjectType,
1807	Loc: SourceLocation (), Diag: PDiag());
1808	}
1809
1810	void HandleDependentAccessCheck(
1811	const DependentDiagnostic &DD,
1812	const MultiLevelTemplateArgumentList &TemplateArgs);
1813	void HandleDelayedAccessCheck(sema::DelayedDiagnostic &DD, Decl *Ctx);
1814
1815	///@}
1816
1817	//
1818	//
1819	// -------------------------------------------------------------------------
1820	//
1821	//
1822
1823	/// \name Attributes
1824	/// Implementations are in SemaAttr.cpp
1825	///@{
1826
1827	public:
1828	/// Controls member pointer representation format under the MS ABI.
1829	LangOptions::PragmaMSPointersToMembersKind
1830	MSPointerToMemberRepresentationMethod;
1831
1832	bool MSStructPragmaOn; // True when \#pragma ms_struct on
1833
1834	/// Source location for newly created implicit MSInheritanceAttrs
1835	SourceLocation ImplicitMSInheritanceAttrLoc;
1836
1837	struct PragmaClangSection {
1838	std::string SectionName;
1839	bool Valid = false;
1840	SourceLocation PragmaLocation;
1841	};
1842
1843	PragmaClangSection PragmaClangBSSSection;
1844	PragmaClangSection PragmaClangDataSection;
1845	PragmaClangSection PragmaClangRodataSection;
1846	PragmaClangSection PragmaClangRelroSection;
1847	PragmaClangSection PragmaClangTextSection;
1848
1849	enum PragmaMsStackAction {
1850	PSK_Reset = `0x0`, // #pragma ()
1851	PSK_Set = `0x1`, // #pragma (value)
1852	PSK_Push = `0x2`, // #pragma (push[, id])
1853	PSK_Pop = `0x4`, // #pragma (pop[, id])
1854	PSK_Show = `0x8`, // #pragma (show) -- only for "pack"!
1855	PSK_Push_Set = PSK_Push \| PSK_Set, // #pragma (push[, id], value)
1856	PSK_Pop_Set = PSK_Pop \| PSK_Set, // #pragma (pop[, id], value)
1857	};
1858
1859	struct PragmaPackInfo {
1860	PragmaMsStackAction Action;
1861	StringRef SlotLabel;
1862	Token Alignment;
1863	};
1864
1865	// #pragma pack and align.
1866	class AlignPackInfo {
1867	public:
1868	// `Native` represents default align mode, which may vary based on the
1869	// platform.
1870	enum Mode : unsigned char { Native, Natural, Packed, Mac68k };
1871
1872	// #pragma pack info constructor
1873	AlignPackInfo(AlignPackInfo::Mode M, unsigned Num, bool IsXL)
1874	: PackAttr(true), AlignMode(M), PackNumber(Num), XLStack(IsXL) {
1875	assert(Num == PackNumber && "The pack number has been truncated.");
1876	}
1877
1878	// #pragma align info constructor
1879	AlignPackInfo(AlignPackInfo::Mode M, bool IsXL)
1880	: PackAttr(false), AlignMode(M),
1881	PackNumber(M == Packed ? `1` : UninitPackVal), XLStack(IsXL) {}
1882
1883	explicit AlignPackInfo(bool IsXL) : AlignPackInfo (Native, IsXL) {}
1884
1885	AlignPackInfo() : AlignPackInfo (Native, false) {}
1886
1887	// When a AlignPackInfo itself cannot be used, this returns an 32-bit
1888	// integer encoding for it. This should only be passed to
1889	// AlignPackInfo::getFromRawEncoding, it should not be inspected directly.
1890	static uint32_t getRawEncoding(const AlignPackInfo &Info) {
1891	std::uint32_t Encoding{};
1892	if (Info.IsXLStack())
1893	Encoding \|= IsXLMask;
1894
1895	Encoding \|= static_cast<uint32_t>(Info.getAlignMode()) << `1`;
1896
1897	if (Info.IsPackAttr())
1898	Encoding \|= PackAttrMask;
1899
1900	Encoding \|= static_cast<uint32_t>(Info.getPackNumber()) << `4`;
1901
1902	return Encoding;
1903	}
1904
1905	static AlignPackInfo getFromRawEncoding(unsigned Encoding) {
1906	bool IsXL = static_cast<bool>(Encoding & IsXLMask);
1907	AlignPackInfo::Mode M =
1908	static_cast<AlignPackInfo::Mode>((Encoding & AlignModeMask) >> `1`);
1909	int PackNumber = (Encoding & PackNumMask) >> `4`;
1910
1911	if (Encoding & PackAttrMask)
1912	return AlignPackInfo (M, PackNumber, IsXL);
1913
1914	return AlignPackInfo (M, IsXL);
1915	}
1916
1917	bool IsPackAttr() const { return PackAttr; }
1918
1919	bool IsAlignAttr() const { return !PackAttr; }
1920
1921	Mode getAlignMode() const { return AlignMode; }
1922
1923	unsigned getPackNumber() const { return PackNumber; }
1924
1925	bool IsPackSet() const {
1926	// #pragma align, #pragma pack(), and #pragma pack(0) do not set the pack
1927	// attriute on a decl.
1928	return PackNumber != UninitPackVal && PackNumber != `0`;
1929	}
1930
1931	bool IsXLStack() const { return XLStack; }
1932
1933	bool operator==(const AlignPackInfo &Info) const {
1934	return std::tie(args: AlignMode, args: PackNumber, args: PackAttr, args: XLStack) ==
1935	std::tie(args: Info.AlignMode, args: Info.PackNumber, args: Info.PackAttr,
1936	args: Info.XLStack);
1937	}
1938
1939	bool operator!=(const AlignPackInfo &Info) const {
1940	return !(*this == Info);
1941	}
1942
1943	private:
1944	/// \brief True if this is a pragma pack attribute,
1945	/// not a pragma align attribute.
1946	bool PackAttr;
1947
1948	/// \brief The alignment mode that is in effect.
1949	Mode AlignMode;
1950
1951	/// \brief The pack number of the stack.
1952	unsigned char PackNumber;
1953
1954	/// \brief True if it is a XL #pragma align/pack stack.
1955	bool XLStack;
1956
1957	/// \brief Uninitialized pack value.
1958	static constexpr unsigned char UninitPackVal = -`1`;
1959
1960	// Masks to encode and decode an AlignPackInfo.
1961	static constexpr uint32_t IsXLMask{`0x0000'0001`};
1962	static constexpr uint32_t AlignModeMask{`0x0000'0006`};
1963	static constexpr uint32_t PackAttrMask{`0x00000'0008`};
1964	static constexpr uint32_t PackNumMask{`0x0000'01F0`};
1965	};
1966
1967	template <typename ValueType> struct PragmaStack {
1968	struct Slot {
1969	llvm::StringRef StackSlotLabel;
1970	ValueType Value;
1971	SourceLocation PragmaLocation;
1972	SourceLocation PragmaPushLocation;
1973	Slot(llvm::StringRef StackSlotLabel, ValueType Value,
1974	SourceLocation PragmaLocation, SourceLocation PragmaPushLocation)
1975	: StackSlotLabel (StackSlotLabel), Value(Value),
1976	PragmaLocation (PragmaLocation),
1977	PragmaPushLocation (PragmaPushLocation) {}
1978	};
1979
1980	void Act(SourceLocation PragmaLocation, PragmaMsStackAction Action,
1981	llvm::StringRef StackSlotLabel, ValueType Value) {
1982	if (Action == PSK_Reset) {
1983	CurrentValue = DefaultValue;
1984	CurrentPragmaLocation = PragmaLocation;
1985	return;
1986	}
1987	if (Action & PSK_Push)
1988	Stack.emplace_back(StackSlotLabel, CurrentValue, CurrentPragmaLocation,
1989	PragmaLocation);
1990	else if (Action & PSK_Pop) {
1991	if (!StackSlotLabel.empty()) {
1992	// If we've got a label, try to find it and jump there.
1993	auto I = llvm::find_if(llvm::reverse(Stack), [&](const Slot &x) {
1994	return x.StackSlotLabel == StackSlotLabel;
1995	});
1996	// If we found the label so pop from there.
1997	if (I != Stack.rend()) {
1998	CurrentValue = I->Value;
1999	CurrentPragmaLocation = I->PragmaLocation;
2000	Stack.erase(std::prev(I.base()), Stack.end());
2001	}
2002	} else if (!Stack.empty()) {
2003	// We do not have a label, just pop the last entry.
2004	CurrentValue = Stack.back().Value;
2005	CurrentPragmaLocation = Stack.back().PragmaLocation;
2006	Stack.pop_back();
2007	}
2008	}
2009	if (Action & PSK_Set) {
2010	CurrentValue = Value;
2011	CurrentPragmaLocation = PragmaLocation;
2012	}
2013	}
2014
2015	// MSVC seems to add artificial slots to #pragma stacks on entering a C++
2016	// method body to restore the stacks on exit, so it works like this:
2017	//
2018	// struct S {
2019	// #pragma <name>(push, InternalPragmaSlot, <current_pragma_value>)
2020	// void Method {}
2021	// #pragma <name>(pop, InternalPragmaSlot)
2022	// };
2023	//
2024	// It works even with #pragma vtordisp, although MSVC doesn't support
2025	// #pragma vtordisp(push [, id], n)
2026	// syntax.
2027	//
2028	// Push / pop a named sentinel slot.
2029	void SentinelAction(PragmaMsStackAction Action, StringRef Label) {
2030	assert((Action == PSK_Push \|\| Action == PSK_Pop) &&
2031	"Can only push / pop #pragma stack sentinels!");
2032	Act(PragmaLocation: CurrentPragmaLocation, Action, StackSlotLabel: Label, Value: CurrentValue);
2033	}
2034
2035	// Constructors.
2036	explicit PragmaStack(const ValueType &Default)
2037	: DefaultValue(Default), CurrentValue(Default) {}
2038
2039	bool hasValue() const { return CurrentValue != DefaultValue; }
2040
2041	SmallVector<Slot, `2`> Stack;
2042	ValueType DefaultValue; // Value used for PSK_Reset action.
2043	ValueType CurrentValue;
2044	SourceLocation CurrentPragmaLocation;
2045	};
2046	// FIXME: We should serialize / deserialize these if they occur in a PCH (but
2047	// we shouldn't do so if they're in a module).
2048
2049	/// Whether to insert vtordisps prior to virtual bases in the Microsoft
2050	/// C++ ABI. Possible values are 0, 1, and 2, which mean:
2051	///
2052	/// 0: Suppress all vtordisps
2053	/// 1: Insert vtordisps in the presence of vbase overrides and non-trivial
2054	/// structors
2055	/// 2: Always insert vtordisps to support RTTI on partially constructed
2056	/// objects
2057	PragmaStack<MSVtorDispMode> VtorDispStack;
2058	PragmaStack<AlignPackInfo> AlignPackStack;
2059	// The current #pragma align/pack values and locations at each #include.
2060	struct AlignPackIncludeState {
2061	AlignPackInfo CurrentValue;
2062	SourceLocation CurrentPragmaLocation;
2063	bool HasNonDefaultValue, ShouldWarnOnInclude;
2064	};
2065	SmallVector<AlignPackIncludeState, `8`> AlignPackIncludeStack;
2066	// Segment #pragmas.
2067	PragmaStack<StringLiteral *> DataSegStack;
2068	PragmaStack<StringLiteral *> BSSSegStack;
2069	PragmaStack<StringLiteral *> ConstSegStack;
2070	PragmaStack<StringLiteral *> CodeSegStack;
2071
2072	// #pragma strict_gs_check.
2073	PragmaStack<bool> StrictGuardStackCheckStack;
2074
2075	// This stack tracks the current state of Sema.CurFPFeatures.
2076	PragmaStack<FPOptionsOverride> FpPragmaStack;
2077	FPOptionsOverride CurFPFeatureOverrides() {
2078	FPOptionsOverride result;
2079	if (!FpPragmaStack.hasValue()) {
2080	result = FPOptionsOverride ();
2081	} else {
2082	result = FpPragmaStack.CurrentValue;
2083	}
2084	return result;
2085	}
2086
2087	enum PragmaSectionKind {
2088	PSK_DataSeg,
2089	PSK_BSSSeg,
2090	PSK_ConstSeg,
2091	PSK_CodeSeg,
2092	};
2093
2094	// RAII object to push / pop sentinel slots for all MS #pragma stacks.
2095	// Actions should be performed only if we enter / exit a C++ method body.
2096	class PragmaStackSentinelRAII {
2097	public:
2098	PragmaStackSentinelRAII(Sema &S, StringRef SlotLabel, bool ShouldAct);
2099	~PragmaStackSentinelRAII();
2100	PragmaStackSentinelRAII(const PragmaStackSentinelRAII &) = delete;
2101	PragmaStackSentinelRAII &
2102	operator=(const PragmaStackSentinelRAII &) = delete;
2103
2104	private:
2105	Sema &S;
2106	StringRef SlotLabel;
2107	bool ShouldAct;
2108	};
2109
2110	/// Last section used with #pragma init_seg.
2111	StringLiteral *CurInitSeg;
2112	SourceLocation CurInitSegLoc;
2113
2114	/// Sections used with #pragma alloc_text.
2115	llvm::StringMap<std::tuple<StringRef, SourceLocation>> FunctionToSectionMap;
2116
2117	/// VisContext - Manages the stack for \#pragma GCC visibility.
2118	void VisContext; // Really a "PragmaVisStack"
2119
2120	/// This an attribute introduced by \#pragma clang attribute.
2121	struct PragmaAttributeEntry {
2122	SourceLocation Loc;
2123	ParsedAttr *Attribute;
2124	SmallVector<attr::SubjectMatchRule, `4`> MatchRules;
2125	bool IsUsed;
2126	};
2127
2128	/// A push'd group of PragmaAttributeEntries.
2129	struct PragmaAttributeGroup {
2130	/// The location of the push attribute.
2131	SourceLocation Loc;
2132	/// The namespace of this push group.
2133	const IdentifierInfo *Namespace;
2134	SmallVector<PragmaAttributeEntry, `2`> Entries;
2135	};
2136
2137	SmallVector<PragmaAttributeGroup, `2`> PragmaAttributeStack;
2138
2139	/// The declaration that is currently receiving an attribute from the
2140	/// #pragma attribute stack.
2141	const Decl *PragmaAttributeCurrentTargetDecl;
2142
2143	/// This represents the last location of a "#pragma clang optimize off"
2144	/// directive if such a directive has not been closed by an "on" yet. If
2145	/// optimizations are currently "on", this is set to an invalid location.
2146	SourceLocation OptimizeOffPragmaLocation;
2147
2148	/// Get the location for the currently active "\#pragma clang optimize
2149	/// off". If this location is invalid, then the state of the pragma is "on".
2150	SourceLocation getOptimizeOffPragmaLocation() const {
2151	return OptimizeOffPragmaLocation;
2152	}
2153
2154	/// The "on" or "off" argument passed by \#pragma optimize, that denotes
2155	/// whether the optimizations in the list passed to the pragma should be
2156	/// turned off or on. This boolean is true by default because command line
2157	/// options are honored when `#pragma optimize("", on)`.
2158	/// (i.e. `ModifyFnAttributeMSPragmaOptimze()` does nothing)
2159	bool MSPragmaOptimizeIsOn = true;
2160
2161	/// Set of no-builtin functions listed by \#pragma function.
2162	llvm::SmallSetVector<StringRef, `4`> MSFunctionNoBuiltins;
2163
2164	/// AddAlignmentAttributesForRecord - Adds any needed alignment attributes to
2165	/// a the record decl, to handle '\#pragma pack' and '\#pragma options align'.
2166	void AddAlignmentAttributesForRecord(RecordDecl *RD);
2167
2168	/// AddMsStructLayoutForRecord - Adds ms_struct layout attribute to record.
2169	void AddMsStructLayoutForRecord(RecordDecl *RD);
2170
2171	/// Add gsl::Pointer attribute to std::container::iterator
2172	/// \param ND The declaration that introduces the name
2173	/// std::container::iterator. \param UnderlyingRecord The record named by ND.
2174	void inferGslPointerAttribute(NamedDecl ND, CXXRecordDecl UnderlyingRecord);
2175
2176	/// Add [[gsl::Owner]] and [[gsl::Pointer]] attributes for std:: types.
2177	void inferGslOwnerPointerAttribute(CXXRecordDecl *Record);
2178
2179	/// Add [[clang:::lifetimebound]] attr for std:: functions and methods.
2180	void inferLifetimeBoundAttribute(FunctionDecl *FD);
2181
2182	/// Add [[clang:::lifetime_capture_by(this)]] to STL container methods.
2183	void inferLifetimeCaptureByAttribute(FunctionDecl *FD);
2184
2185	/// Add [[gsl::Pointer]] attributes for std:: types.
2186	void inferGslPointerAttribute(TypedefNameDecl *TD);
2187
2188	LifetimeCaptureByAttr ParseLifetimeCaptureByAttr(const* ParsedAttr &AL,
2189	StringRef ParamName);
2190	// Processes the argument 'X' in [[clang::lifetime_capture_by(X)]]. Since 'X'
2191	// can be the name of a function parameter, we need to parse the function
2192	// declaration and rest of the parameters before processesing 'X'. Therefore
2193	// do this lazily instead of processing while parsing the annotation itself.
2194	void LazyProcessLifetimeCaptureByParams(FunctionDecl *FD);
2195
2196	/// Add _Nullable attributes for std:: types.
2197	void inferNullableClassAttribute(CXXRecordDecl *CRD);
2198
2199	/// ActOnPragmaClangSection - Called on well formed \#pragma clang section
2200	void ActOnPragmaClangSection(SourceLocation PragmaLoc,
2201	PragmaClangSectionAction Action,
2202	PragmaClangSectionKind SecKind,
2203	StringRef SecName);
2204
2205	/// ActOnPragmaOptionsAlign - Called on well formed \#pragma options align.
2206	void ActOnPragmaOptionsAlign(PragmaOptionsAlignKind Kind,
2207	SourceLocation PragmaLoc);
2208
2209	/// ActOnPragmaPack - Called on well formed \#pragma pack(...).
2210	void ActOnPragmaPack(SourceLocation PragmaLoc, PragmaMsStackAction Action,
2211	StringRef SlotLabel, Expr *Alignment);
2212
2213	/// ConstantFoldAttrArgs - Folds attribute arguments into ConstantExprs
2214	/// (unless they are value dependent or type dependent). Returns false
2215	/// and emits a diagnostic if one or more of the arguments could not be
2216	/// folded into a constant.
2217	bool ConstantFoldAttrArgs(const AttributeCommonInfo &CI,
2218	MutableArrayRef<Expr *> Args);
2219
2220	enum class PragmaAlignPackDiagnoseKind {
2221	NonDefaultStateAtInclude,
2222	ChangedStateAtExit
2223	};
2224
2225	void DiagnoseNonDefaultPragmaAlignPack(PragmaAlignPackDiagnoseKind Kind,
2226	SourceLocation IncludeLoc);
2227	void DiagnoseUnterminatedPragmaAlignPack();
2228
2229	/// ActOnPragmaMSStruct - Called on well formed \#pragma ms_struct [on\|off].
2230	void ActOnPragmaMSStruct(PragmaMSStructKind Kind);
2231
2232	/// ActOnPragmaMSComment - Called on well formed
2233	/// \#pragma comment(kind, "arg").
2234	void ActOnPragmaMSComment(SourceLocation CommentLoc, PragmaMSCommentKind Kind,
2235	StringRef Arg);
2236
2237	/// ActOnPragmaDetectMismatch - Call on well-formed \#pragma detect_mismatch
2238	void ActOnPragmaDetectMismatch(SourceLocation Loc, StringRef Name,
2239	StringRef Value);
2240
2241	/// Are precise floating point semantics currently enabled?
2242	bool isPreciseFPEnabled() {
2243	return !CurFPFeatures.getAllowFPReassociate() &&
2244	!CurFPFeatures.getNoSignedZero() &&
2245	!CurFPFeatures.getAllowReciprocal() &&
2246	!CurFPFeatures.getAllowApproxFunc();
2247	}
2248
2249	void ActOnPragmaFPEvalMethod(SourceLocation Loc,
2250	LangOptions::FPEvalMethodKind Value);
2251
2252	/// ActOnPragmaFloatControl - Call on well-formed \#pragma float_control
2253	void ActOnPragmaFloatControl(SourceLocation Loc, PragmaMsStackAction Action,
2254	PragmaFloatControlKind Value);
2255
2256	/// ActOnPragmaMSPointersToMembers - called on well formed \#pragma
2257	/// pointers_to_members(representation method[, general purpose
2258	/// representation]).
2259	void ActOnPragmaMSPointersToMembers(
2260	LangOptions::PragmaMSPointersToMembersKind Kind,
2261	SourceLocation PragmaLoc);
2262
2263	/// Called on well formed \#pragma vtordisp().
2264	void ActOnPragmaMSVtorDisp(PragmaMsStackAction Action,
2265	SourceLocation PragmaLoc, MSVtorDispMode Value);
2266
2267	bool UnifySection(StringRef SectionName, int SectionFlags,
2268	NamedDecl *TheDecl);
2269	bool UnifySection(StringRef SectionName, int SectionFlags,
2270	SourceLocation PragmaSectionLocation);
2271
2272	/// Called on well formed \#pragma bss_seg/data_seg/const_seg/code_seg.
2273	void ActOnPragmaMSSeg(SourceLocation PragmaLocation,
2274	PragmaMsStackAction Action,
2275	llvm::StringRef StackSlotLabel,
2276	StringLiteral *SegmentName, llvm::StringRef PragmaName);
2277
2278	/// Called on well formed \#pragma section().
2279	void ActOnPragmaMSSection(SourceLocation PragmaLocation, int SectionFlags,
2280	StringLiteral *SegmentName);
2281
2282	/// Called on well-formed \#pragma init_seg().
2283	void ActOnPragmaMSInitSeg(SourceLocation PragmaLocation,
2284	StringLiteral *SegmentName);
2285
2286	/// Called on well-formed \#pragma alloc_text().
2287	void ActOnPragmaMSAllocText(
2288	SourceLocation PragmaLocation, StringRef Section,
2289	const SmallVector<std::tuple<IdentifierInfo *, SourceLocation>>
2290	&Functions);
2291
2292	/// ActOnPragmaMSStrictGuardStackCheck - Called on well formed \#pragma
2293	/// strict_gs_check.
2294	void ActOnPragmaMSStrictGuardStackCheck(SourceLocation PragmaLocation,
2295	PragmaMsStackAction Action,
2296	bool Value);
2297
2298	/// ActOnPragmaUnused - Called on well-formed '\#pragma unused'.
2299	void ActOnPragmaUnused(const Token &Identifier, Scope *curScope,
2300	SourceLocation PragmaLoc);
2301
2302	void ActOnPragmaAttributeAttribute(ParsedAttr &Attribute,
2303	SourceLocation PragmaLoc,
2304	attr::ParsedSubjectMatchRuleSet Rules);
2305	void ActOnPragmaAttributeEmptyPush(SourceLocation PragmaLoc,
2306	const IdentifierInfo *Namespace);
2307
2308	/// Called on well-formed '\#pragma clang attribute pop'.
2309	void ActOnPragmaAttributePop(SourceLocation PragmaLoc,
2310	const IdentifierInfo *Namespace);
2311
2312	/// Adds the attributes that have been specified using the
2313	/// '\#pragma clang attribute push' directives to the given declaration.
2314	void AddPragmaAttributes(Scope S, Decl D);
2315
2316	using InstantiationContextDiagFuncRef =
2317	llvm::function_ref<void(SourceLocation, PartialDiagnostic)>;
2318	auto getDefaultDiagFunc() {
2319	return [this](SourceLocation Loc, PartialDiagnostic PD) {
2320	// This bypasses a lot of the filters in the diag engine, as it's
2321	// to be used to attach notes to diagnostics which have already
2322	// been filtered through.
2323	DiagnosticBuilder Builder(Diags.Report(Loc, DiagID: PD.getDiagID()));
2324	PD.Emit(DB: Builder);
2325	};
2326	}
2327
2328	void PrintPragmaAttributeInstantiationPoint(
2329	InstantiationContextDiagFuncRef DiagFunc);
2330	void PrintPragmaAttributeInstantiationPoint() {
2331	PrintPragmaAttributeInstantiationPoint(DiagFunc: getDefaultDiagFunc());
2332	}
2333
2334	void DiagnoseUnterminatedPragmaAttribute();
2335
2336	/// Called on well formed \#pragma clang optimize.
2337	void ActOnPragmaOptimize(bool On, SourceLocation PragmaLoc);
2338
2339	/// #pragma optimize("[optimization-list]", on \| off).
2340	void ActOnPragmaMSOptimize(SourceLocation Loc, bool IsOn);
2341
2342	/// Call on well formed \#pragma function.
2343	void
2344	ActOnPragmaMSFunction(SourceLocation Loc,
2345	const llvm::SmallVectorImpl<StringRef> &NoBuiltins);
2346
2347	NamedDecl lookupExternCFunctionOrVariable(IdentifierInfo IdentId,
2348	SourceLocation NameLoc,
2349	Scope *curScope);
2350
2351	/// Information from a C++ #pragma export, for a symbol that we
2352	/// haven't seen the declaration for yet.
2353	struct PendingPragmaInfo {
2354	SourceLocation NameLoc;
2355	bool Used;
2356	};
2357
2358	llvm::DenseMap<IdentifierInfo *, PendingPragmaInfo> PendingExportedNames;
2359
2360	/// ActonPragmaExport - called on well-formed '\#pragma export'.
2361	void ActOnPragmaExport(IdentifierInfo *IdentId, SourceLocation ExportNameLoc,
2362	Scope *curScope);
2363
2364	/// Only called on function definitions; if there is a pragma in scope
2365	/// with the effect of a range-based optnone, consider marking the function
2366	/// with attribute optnone.
2367	void AddRangeBasedOptnone(FunctionDecl *FD);
2368
2369	/// Only called on function definitions; if there is a `#pragma alloc_text`
2370	/// that decides which code section the function should be in, add
2371	/// attribute section to the function.
2372	void AddSectionMSAllocText(FunctionDecl *FD);
2373
2374	/// Adds the 'optnone' attribute to the function declaration if there
2375	/// are no conflicts; Loc represents the location causing the 'optnone'
2376	/// attribute to be added (usually because of a pragma).
2377	void AddOptnoneAttributeIfNoConflicts(FunctionDecl *FD, SourceLocation Loc);
2378
2379	/// Only called on function definitions; if there is a MSVC #pragma optimize
2380	/// in scope, consider changing the function's attributes based on the
2381	/// optimization list passed to the pragma.
2382	void ModifyFnAttributesMSPragmaOptimize(FunctionDecl *FD);
2383
2384	/// Only called on function definitions; if there is a pragma in scope
2385	/// with the effect of a range-based no_builtin, consider marking the function
2386	/// with attribute no_builtin.
2387	void AddImplicitMSFunctionNoBuiltinAttr(FunctionDecl *FD);
2388
2389	/// AddPushedVisibilityAttribute - If '\#pragma GCC visibility' was used,
2390	/// add an appropriate visibility attribute.
2391	void AddPushedVisibilityAttribute(Decl *RD);
2392
2393	/// FreeVisContext - Deallocate and null out VisContext.
2394	void FreeVisContext();
2395
2396	/// ActOnPragmaVisibility - Called on well formed \#pragma GCC visibility... .
2397	void ActOnPragmaVisibility(const IdentifierInfo *VisType,
2398	SourceLocation PragmaLoc);
2399
2400	/// ActOnPragmaFPContract - Called on well formed
2401	/// \#pragma {STDC,OPENCL} FP_CONTRACT and
2402	/// \#pragma clang fp contract
2403	void ActOnPragmaFPContract(SourceLocation Loc, LangOptions::FPModeKind FPC);
2404
2405	/// Called on well formed
2406	/// \#pragma clang fp reassociate
2407	/// or
2408	/// \#pragma clang fp reciprocal
2409	void ActOnPragmaFPValueChangingOption(SourceLocation Loc, PragmaFPKind Kind,
2410	bool IsEnabled);
2411
2412	/// ActOnPragmaFenvAccess - Called on well formed
2413	/// \#pragma STDC FENV_ACCESS
2414	void ActOnPragmaFEnvAccess(SourceLocation Loc, bool IsEnabled);
2415
2416	/// ActOnPragmaCXLimitedRange - Called on well formed
2417	/// \#pragma STDC CX_LIMITED_RANGE
2418	void ActOnPragmaCXLimitedRange(SourceLocation Loc,
2419	LangOptions::ComplexRangeKind Range);
2420
2421	/// Called on well formed '\#pragma clang fp' that has option 'exceptions'.
2422	void ActOnPragmaFPExceptions(SourceLocation Loc,
2423	LangOptions::FPExceptionModeKind);
2424
2425	/// Called to set constant rounding mode for floating point operations.
2426	void ActOnPragmaFEnvRound(SourceLocation Loc, llvm::RoundingMode);
2427
2428	/// Called to set exception behavior for floating point operations.
2429	void setExceptionMode(SourceLocation Loc, LangOptions::FPExceptionModeKind);
2430
2431	/// PushNamespaceVisibilityAttr - Note that we've entered a
2432	/// namespace with a visibility attribute.
2433	void PushNamespaceVisibilityAttr(const VisibilityAttr *Attr,
2434	SourceLocation Loc);
2435
2436	/// PopPragmaVisibility - Pop the top element of the visibility stack; used
2437	/// for '\#pragma GCC visibility' and visibility attributes on namespaces.
2438	void PopPragmaVisibility(bool IsNamespaceEnd, SourceLocation EndLoc);
2439
2440	/// Handles semantic checking for features that are common to all attributes,
2441	/// such as checking whether a parameter was properly specified, or the
2442	/// correct number of arguments were passed, etc. Returns true if the
2443	/// attribute has been diagnosed.
2444	bool checkCommonAttributeFeatures(const Decl D, const* ParsedAttr &A,
2445	bool SkipArgCountCheck = false);
2446	bool checkCommonAttributeFeatures(const Stmt S, const* ParsedAttr &A,
2447	bool SkipArgCountCheck = false);
2448
2449	///@}
2450
2451	//
2452	//
2453	// -------------------------------------------------------------------------
2454	//
2455	//
2456
2457	/// \name Availability Attribute Handling
2458	/// Implementations are in SemaAvailability.cpp
2459	///@{
2460
2461	public:
2462	/// Issue any -Wunguarded-availability warnings in \c FD
2463	void DiagnoseUnguardedAvailabilityViolations(Decl *FD);
2464
2465	void handleDelayedAvailabilityCheck(sema::DelayedDiagnostic &DD, Decl *Ctx);
2466
2467	/// Retrieve the current function, if any, that should be analyzed for
2468	/// potential availability violations.
2469	sema::FunctionScopeInfo *getCurFunctionAvailabilityContext();
2470
2471	void DiagnoseAvailabilityOfDecl(NamedDecl *D, ArrayRef<SourceLocation> Locs,
2472	const ObjCInterfaceDecl *UnknownObjCClass,
2473	bool ObjCPropertyAccess,
2474	bool AvoidPartialAvailabilityChecks,
2475	ObjCInterfaceDecl *ClassReceiver);
2476
2477	void DiagnoseAvailabilityOfDecl(NamedDecl *D, ArrayRef<SourceLocation> Locs);
2478
2479	std::pair<AvailabilityResult, const NamedDecl *>
2480	ShouldDiagnoseAvailabilityOfDecl(const NamedDecl D, std::string Message,
2481	ObjCInterfaceDecl *ClassReceiver);
2482	///@}
2483
2484	//
2485	//
2486	// -------------------------------------------------------------------------
2487	//
2488	//
2489
2490	/// \name Bounds Safety
2491	/// Implementations are in SemaBoundsSafety.cpp
2492	///@{
2493	public:
2494	/// Check if applying the specified attribute variant from the "counted by"
2495	/// family of attributes to FieldDecl \p FD is semantically valid. If
2496	/// semantically invalid diagnostics will be emitted explaining the problems.
2497	///
2498	/// \param FD The FieldDecl to apply the attribute to
2499	/// \param E The count expression on the attribute
2500	/// \param CountInBytes If true the attribute is from the "sized_by" family of
2501	/// attributes. If the false the attribute is from
2502	/// "counted_by" family of attributes.
2503	/// \param OrNull If true the attribute is from the "_or_null" suffixed family
2504	/// of attributes. If false the attribute does not have the
2505	/// suffix.
2506	///
2507	/// Together \p CountInBytes and \p OrNull decide the attribute variant. E.g.
2508	/// \p CountInBytes and \p OrNull both being true indicates the
2509	/// `counted_by_or_null` attribute.
2510	///
2511	/// \returns false iff semantically valid.
2512	bool CheckCountedByAttrOnField(FieldDecl FD, Expr E, bool CountInBytes,
2513	bool OrNull);
2514
2515	/// Perform Bounds Safety Semantic checks for assigning to a `__counted_by` or
2516	/// `__counted_by_or_null` pointer type \param LHSTy.
2517	///
2518	/// \param LHSTy The type being assigned to. Checks will only be performed if
2519	/// the type is a `counted_by` or `counted_by_or_null ` pointer.
2520	/// \param RHSExpr The expression being assigned from.
2521	/// \param Action The type assignment being performed
2522	/// \param Loc The SourceLocation to use for error diagnostics
2523	/// \param Assignee The ValueDecl being assigned. This is used to compute
2524	/// the name of the assignee. If the assignee isn't known this can
2525	/// be set to nullptr.
2526	/// \param ShowFullyQualifiedAssigneeName If set to true when using \p
2527	/// Assignee to compute the name of the assignee use the fully
2528	/// qualified name, otherwise use the unqualified name.
2529	///
2530	/// \returns True iff no diagnostic where emitted, false otherwise.
2531	bool BoundsSafetyCheckAssignmentToCountAttrPtr(
2532	QualType LHSTy, Expr *RHSExpr, AssignmentAction Action,
2533	SourceLocation Loc, const ValueDecl *Assignee,
2534	bool ShowFullyQualifiedAssigneeName);
2535
2536	/// Perform Bounds Safety Semantic checks for initializing a Bounds Safety
2537	/// pointer.
2538	///
2539	/// \param Entity The entity being initialized
2540	/// \param Kind The kind of initialization being performed
2541	/// \param Action The type assignment being performed
2542	/// \param LHSTy The type being assigned to. Checks will only be performed if
2543	/// the type is a `counted_by` or `counted_by_or_null ` pointer.
2544	/// \param RHSExpr The expression being used for initialization.
2545	///
2546	/// \returns True iff no diagnostic where emitted, false otherwise.
2547	bool BoundsSafetyCheckInitialization(const InitializedEntity &Entity,
2548	const InitializationKind &Kind,
2549	AssignmentAction Action,
2550	QualType LHSType, Expr *RHSExpr);
2551
2552	/// Perform Bounds Safety semantic checks for uses of invalid uses counted_by
2553	/// or counted_by_or_null pointers in \param E.
2554	///
2555	/// \param E the expression to check
2556	///
2557	/// \returns True iff no diagnostic where emitted, false otherwise.
2558	bool BoundsSafetyCheckUseOfCountAttrPtr(const Expr *E);
2559	///@}
2560
2561	//
2562	//
2563	// -------------------------------------------------------------------------
2564	//
2565	//
2566
2567	/// \name Casts
2568	/// Implementations are in SemaCast.cpp
2569	///@{
2570
2571	public:
2572	static bool isCast(CheckedConversionKind CCK) {
2573	return CCK == CheckedConversionKind::CStyleCast \|\|
2574	CCK == CheckedConversionKind::FunctionalCast \|\|
2575	CCK == CheckedConversionKind::OtherCast;
2576	}
2577
2578	/// ActOnCXXNamedCast - Parse
2579	/// {dynamic,static,reinterpret,const,addrspace}_cast's.
2580	ExprResult ActOnCXXNamedCast(SourceLocation OpLoc, tok::TokenKind Kind,
2581	SourceLocation LAngleBracketLoc, Declarator &D,
2582	SourceLocation RAngleBracketLoc,
2583	SourceLocation LParenLoc, Expr *E,
2584	SourceLocation RParenLoc);
2585
2586	ExprResult BuildCXXNamedCast(SourceLocation OpLoc, tok::TokenKind Kind,
2587	TypeSourceInfo Ty, Expr E,
2588	SourceRange AngleBrackets, SourceRange Parens);
2589
2590	ExprResult ActOnBuiltinBitCastExpr(SourceLocation KWLoc, Declarator &Dcl,
2591	ExprResult Operand,
2592	SourceLocation RParenLoc);
2593
2594	ExprResult BuildBuiltinBitCastExpr(SourceLocation KWLoc, TypeSourceInfo *TSI,
2595	Expr *Operand, SourceLocation RParenLoc);
2596
2597	// Checks that reinterpret casts don't have undefined behavior.
2598	void CheckCompatibleReinterpretCast(QualType SrcType, QualType DestType,
2599	bool IsDereference, SourceRange Range);
2600
2601	// Checks that the vector type should be initialized from a scalar
2602	// by splatting the value rather than populating a single element.
2603	// This is the case for AltiVecVector types as well as with
2604	// AltiVecPixel and AltiVecBool when -faltivec-src-compat=xl is specified.
2605	bool ShouldSplatAltivecScalarInCast(const VectorType *VecTy);
2606
2607	// Checks if the -faltivec-src-compat=gcc option is specified.
2608	// If so, AltiVecVector, AltiVecBool and AltiVecPixel types are
2609	// treated the same way as they are when trying to initialize
2610	// these vectors on gcc (an error is emitted).
2611	bool CheckAltivecInitFromScalar(SourceRange R, QualType VecTy,
2612	QualType SrcTy);
2613
2614	ExprResult BuildCStyleCastExpr(SourceLocation LParenLoc, TypeSourceInfo *Ty,
2615	SourceLocation RParenLoc, Expr *Op);
2616
2617	ExprResult BuildCXXFunctionalCastExpr(TypeSourceInfo *TInfo, QualType Type,
2618	SourceLocation LParenLoc,
2619	Expr *CastExpr,
2620	SourceLocation RParenLoc);
2621
2622	///@}
2623
2624	//
2625	//
2626	// -------------------------------------------------------------------------
2627	//
2628	//
2629
2630	/// \name Extra Semantic Checking
2631	/// Implementations are in SemaChecking.cpp
2632	///@{
2633
2634	public:
2635	/// Used to change context to isConstantEvaluated without pushing a heavy
2636	/// ExpressionEvaluationContextRecord object.
2637	bool isConstantEvaluatedOverride = false;
2638
2639	bool isConstantEvaluatedContext() const {
2640	return currentEvaluationContext().isConstantEvaluated() \|\|
2641	isConstantEvaluatedOverride;
2642	}
2643
2644	SourceLocation getLocationOfStringLiteralByte(const StringLiteral *SL,
2645	unsigned ByteNo) const;
2646
2647	enum FormatArgumentPassingKind {
2648	FAPK_Fixed, // values to format are fixed (no C-style variadic arguments)
2649	FAPK_Variadic, // values to format are passed as variadic arguments
2650	FAPK_VAList, // values to format are passed in a va_list
2651	FAPK_Elsewhere, // values to format are not passed to this function
2652	};
2653
2654	// Used to grab the relevant information from a FormatAttr and a
2655	// FunctionDeclaration.
2656	struct FormatStringInfo {
2657	unsigned FormatIdx;
2658	unsigned FirstDataArg;
2659	FormatArgumentPassingKind ArgPassingKind;
2660	};
2661
2662	/// Given a function and its FormatAttr or FormatMatchesAttr info, attempts to
2663	/// populate the FormatStringInfo parameter with the attribute's correct
2664	/// format_idx and firstDataArg. Returns true when the format fits the
2665	/// function and the FormatStringInfo has been populated.
2666	static bool getFormatStringInfo(const Decl Function, unsigned* FormatIdx,
2667	unsigned FirstArg, FormatStringInfo *FSI);
2668	static bool getFormatStringInfo(unsigned FormatIdx, unsigned FirstArg,
2669	bool HasImplicitThisParam, bool IsVariadic,
2670	FormatStringInfo *FSI);
2671
2672	// Used by C++ template instantiation.
2673	ExprResult BuiltinShuffleVector(CallExpr *TheCall);
2674
2675	/// ConvertVectorExpr - Handle __builtin_convertvector
2676	ExprResult ConvertVectorExpr(Expr E, TypeSourceInfo TInfo,
2677	SourceLocation BuiltinLoc,
2678	SourceLocation RParenLoc);
2679
2680	static StringRef GetFormatStringTypeName(FormatStringType FST);
2681	static FormatStringType GetFormatStringType(StringRef FormatFlavor);
2682	static FormatStringType GetFormatStringType(const FormatAttr *Format);
2683	static FormatStringType GetFormatStringType(const FormatMatchesAttr *Format);
2684
2685	bool FormatStringHasSArg(const StringLiteral *FExpr);
2686
2687	/// Check for comparisons of floating-point values using == and !=. Issue a
2688	/// warning if the comparison is not likely to do what the programmer
2689	/// intended.
2690	void CheckFloatComparison(SourceLocation Loc, const Expr *LHS,
2691	const Expr *RHS, BinaryOperatorKind Opcode);
2692
2693	/// Register a magic integral constant to be used as a type tag.
2694	void RegisterTypeTagForDatatype(const IdentifierInfo *ArgumentKind,
2695	uint64_t MagicValue, QualType Type,
2696	bool LayoutCompatible, bool MustBeNull);
2697
2698	struct TypeTagData {
2699	TypeTagData() {}
2700
2701	TypeTagData(QualType Type, bool LayoutCompatible, bool MustBeNull)
2702	: Type (Type), LayoutCompatible(LayoutCompatible),
2703	MustBeNull(MustBeNull) {}
2704
2705	QualType Type;
2706
2707	/// If true, \c Type should be compared with other expression's types for
2708	/// layout-compatibility.
2709	LLVM_PREFERRED_TYPE(bool)
2710	unsigned LayoutCompatible : `1`;
2711	LLVM_PREFERRED_TYPE(bool)
2712	unsigned MustBeNull : `1`;
2713	};
2714
2715	/// A pair of ArgumentKind identifier and magic value. This uniquely
2716	/// identifies the magic value.
2717	typedef std::pair<const IdentifierInfo *, uint64_t> TypeTagMagicValue;
2718
2719	/// Diagnoses the current set of gathered accesses. This happens at the end of
2720	/// each expression evaluation context. Diagnostics are emitted only for
2721	/// accesses gathered in the current evaluation context.
2722	void DiagnoseMisalignedMembers();
2723
2724	/// This function checks if the expression is in the sef of potentially
2725	/// misaligned members and it is converted to some pointer type T with lower
2726	/// or equal alignment requirements. If so it removes it. This is used when
2727	/// we do not want to diagnose such misaligned access (e.g. in conversions to
2728	/// void).*
2729	void DiscardMisalignedMemberAddress(const Type T, Expr E);
2730
2731	/// Returns true if `From` is a function or pointer to a function with the
2732	/// `cfi_unchecked_callee` attribute but `To` is a function or pointer to
2733	/// function without this attribute.
2734	bool DiscardingCFIUncheckedCallee(QualType From, QualType To) const;
2735
2736	/// This function calls Action when it determines that E designates a
2737	/// misaligned member due to the packed attribute. This is used to emit
2738	/// local diagnostics like in reference binding.
2739	void RefersToMemberWithReducedAlignment(
2740	Expr *E,
2741	llvm::function_ref<void(Expr , RecordDecl , FieldDecl *, CharUnits)>
2742	Action);
2743
2744	enum class AtomicArgumentOrder { API, AST };
2745	ExprResult
2746	BuildAtomicExpr(SourceRange CallRange, SourceRange ExprRange,
2747	SourceLocation RParenLoc, MultiExprArg Args,
2748	AtomicExpr::AtomicOp Op,
2749	AtomicArgumentOrder ArgOrder = AtomicArgumentOrder::API);
2750
2751	/// Check to see if a given expression could have '.c_str()' called on it.
2752	bool hasCStrMethod(const Expr *E);
2753
2754	/// Diagnose pointers that are always non-null.
2755	/// \param E the expression containing the pointer
2756	/// \param NullKind NPCK_NotNull if E is a cast to bool, otherwise, E is
2757	/// compared to a null pointer
2758	/// \param IsEqual True when the comparison is equal to a null pointer
2759	/// \param Range Extra SourceRange to highlight in the diagnostic
2760	void DiagnoseAlwaysNonNullPointer(Expr *E,
2761	Expr::NullPointerConstantKind NullType,
2762	bool IsEqual, SourceRange Range);
2763
2764	/// CheckParmsForFunctionDef - Check that the parameters of the given
2765	/// function are appropriate for the definition of a function. This
2766	/// takes care of any checks that cannot be performed on the
2767	/// declaration itself, e.g., that the types of each of the function
2768	/// parameters are complete.
2769	bool CheckParmsForFunctionDef(ArrayRef<ParmVarDecl *> Parameters,
2770	bool CheckParameterNames);
2771
2772	/// CheckCastAlign - Implements -Wcast-align, which warns when a
2773	/// pointer cast increases the alignment requirements.
2774	void CheckCastAlign(Expr *Op, QualType T, SourceRange TRange);
2775
2776	/// checkUnsafeAssigns - Check whether +1 expr is being assigned
2777	/// to weak/__unsafe_unretained type.
2778	bool checkUnsafeAssigns(SourceLocation Loc, QualType LHS, Expr *RHS);
2779
2780	/// checkUnsafeExprAssigns - Check whether +1 expr is being assigned
2781	/// to weak/__unsafe_unretained expression.
2782	void checkUnsafeExprAssigns(SourceLocation Loc, Expr LHS, Expr RHS);
2783
2784	/// Emit \p DiagID if statement located on \p StmtLoc has a suspicious null
2785	/// statement as a \p Body, and it is located on the same line.
2786	///
2787	/// This helps prevent bugs due to typos, such as:
2788	/// if (condition);
2789	/// do_stuff();
2790	void DiagnoseEmptyStmtBody(SourceLocation StmtLoc, const Stmt *Body,
2791	unsigned DiagID);
2792
2793	/// Warn if a for/while loop statement \p S, which is followed by
2794	/// \p PossibleBody, has a suspicious null statement as a body.
2795	void DiagnoseEmptyLoopBody(const Stmt S, const* Stmt *PossibleBody);
2796
2797	/// DiagnoseSelfMove - Emits a warning if a value is moved to itself.
2798	void DiagnoseSelfMove(const Expr LHSExpr, const* Expr *RHSExpr,
2799	SourceLocation OpLoc);
2800
2801	bool IsLayoutCompatible(QualType T1, QualType T2) const;
2802	bool IsPointerInterconvertibleBaseOf(const TypeSourceInfo *Base,
2803	const TypeSourceInfo *Derived);
2804
2805	/// CheckFunctionCall - Check a direct function call for various correctness
2806	/// and safety properties not strictly enforced by the C type system.
2807	bool CheckFunctionCall(FunctionDecl FDecl, CallExpr TheCall,
2808	const FunctionProtoType *Proto);
2809
2810	enum class EltwiseBuiltinArgTyRestriction {
2811	None,
2812	FloatTy,
2813	IntegerTy,
2814	SignedIntOrFloatTy,
2815	};
2816
2817	/// \param FPOnly restricts the arguments to floating-point types.
2818	std::optional<QualType>
2819	BuiltinVectorMath(CallExpr *TheCall,
2820	EltwiseBuiltinArgTyRestriction ArgTyRestr =
2821	EltwiseBuiltinArgTyRestriction::None);
2822	bool BuiltinVectorToScalarMath(CallExpr *TheCall);
2823
2824	void checkLifetimeCaptureBy(FunctionDecl FDecl, bool* IsMemberFunction,
2825	const Expr ThisArg, ArrayRef<const* Expr *> Args);
2826
2827	/// Handles the checks for format strings, non-POD arguments to vararg
2828	/// functions, NULL arguments passed to non-NULL parameters, diagnose_if
2829	/// attributes and AArch64 SME attributes.
2830	void checkCall(NamedDecl FDecl, const* FunctionProtoType *Proto,
2831	const Expr ThisArg, ArrayRef<const* Expr *> Args,
2832	bool IsMemberFunction, SourceLocation Loc, SourceRange Range,
2833	VariadicCallType CallType);
2834
2835	/// Verify that two format strings (as understood by attribute(format) and
2836	/// attribute(format_matches) are compatible. If they are incompatible,
2837	/// diagnostics are emitted with the assumption that \c
2838	/// AuthoritativeFormatString is correct and
2839	/// \c TestedFormatString is wrong. If \c FunctionCallArg is provided,
2840	/// diagnostics will point to it and a note will refer to \c
2841	/// TestedFormatString or \c AuthoritativeFormatString as appropriate.
2842	bool
2843	CheckFormatStringsCompatible(FormatStringType FST,
2844	const StringLiteral *AuthoritativeFormatString,
2845	const StringLiteral *TestedFormatString,
2846	const Expr FunctionCallArg = nullptr*);
2847
2848	/// Verify that one format string (as understood by attribute(format)) is
2849	/// self-consistent; for instance, that it doesn't have multiple positional
2850	/// arguments referring to the same argument in incompatible ways. Diagnose
2851	/// if it isn't.
2852	bool ValidateFormatString(FormatStringType FST, const StringLiteral *Str);
2853
2854	/// \brief Enforce the bounds of a TCB
2855	/// CheckTCBEnforcement - Enforces that every function in a named TCB only
2856	/// directly calls other functions in the same TCB as marked by the
2857	/// enforce_tcb and enforce_tcb_leaf attributes.
2858	void CheckTCBEnforcement(const SourceLocation CallExprLoc,
2859	const NamedDecl *Callee);
2860
2861	void CheckConstrainedAuto(const AutoType *AutoT, SourceLocation Loc);
2862
2863	/// BuiltinConstantArg - Handle a check if argument ArgNum of CallExpr
2864	/// TheCall is a constant expression.
2865	bool BuiltinConstantArg(CallExpr TheCall, unsigned* ArgNum,
2866	llvm::APSInt &Result);
2867
2868	/// BuiltinConstantArgRange - Handle a check if argument ArgNum of CallExpr
2869	/// TheCall is a constant expression in the range [Low, High].
2870	bool BuiltinConstantArgRange(CallExpr TheCall, unsigned* ArgNum, int Low,
2871	int High, bool RangeIsError = true);
2872
2873	/// BuiltinConstantArgMultiple - Handle a check if argument ArgNum of CallExpr
2874	/// TheCall is a constant expression is a multiple of Num..
2875	bool BuiltinConstantArgMultiple(CallExpr TheCall, unsigned* ArgNum,
2876	unsigned Multiple);
2877
2878	/// BuiltinConstantArgPower2 - Check if argument ArgNum of TheCall is a
2879	/// constant expression representing a power of 2.
2880	bool BuiltinConstantArgPower2(CallExpr TheCall, unsigned* ArgNum);
2881
2882	/// BuiltinConstantArgShiftedByte - Check if argument ArgNum of TheCall is
2883	/// a constant expression representing an arbitrary byte value shifted left by
2884	/// a multiple of 8 bits.
2885	bool BuiltinConstantArgShiftedByte(CallExpr TheCall, unsigned* ArgNum,
2886	unsigned ArgBits);
2887
2888	/// BuiltinConstantArgShiftedByteOr0xFF - Check if argument ArgNum of
2889	/// TheCall is a constant expression representing either a shifted byte value,
2890	/// or a value of the form 0x??FF (i.e. a member of the arithmetic progression
2891	/// 0x00FF, 0x01FF, ..., 0xFFFF). This strange range check is needed for some
2892	/// Arm MVE intrinsics.
2893	bool BuiltinConstantArgShiftedByteOrXXFF(CallExpr TheCall, unsigned* ArgNum,
2894	unsigned ArgBits);
2895
2896	/// Checks that a call expression's argument count is at least the desired
2897	/// number. This is useful when doing custom type-checking on a variadic
2898	/// function. Returns true on error.
2899	bool checkArgCountAtLeast(CallExpr Call, unsigned* MinArgCount);
2900
2901	/// Checks that a call expression's argument count is at most the desired
2902	/// number. This is useful when doing custom type-checking on a variadic
2903	/// function. Returns true on error.
2904	bool checkArgCountAtMost(CallExpr Call, unsigned* MaxArgCount);
2905
2906	/// Checks that a call expression's argument count is in the desired range.
2907	/// This is useful when doing custom type-checking on a variadic function.
2908	/// Returns true on error.
2909	bool checkArgCountRange(CallExpr Call, unsigned* MinArgCount,
2910	unsigned MaxArgCount);
2911
2912	/// Checks that a call expression's argument count is the desired number.
2913	/// This is useful when doing custom type-checking. Returns true on error.
2914	bool checkArgCount(CallExpr Call, unsigned* DesiredArgCount);
2915
2916	/// Returns true if the argument consists of one contiguous run of 1s with any
2917	/// number of 0s on either side. The 1s are allowed to wrap from LSB to MSB,
2918	/// so 0x000FFF0, 0x0000FFFF, 0xFF0000FF, 0x0 are all runs. 0x0F0F0000 is not,
2919	/// since all 1s are not contiguous.
2920	bool ValueIsRunOfOnes(CallExpr TheCall, unsigned* ArgNum);
2921
2922	void CheckImplicitConversion(Expr *E, QualType T, SourceLocation CC,
2923	bool ICContext = nullptr*,
2924	bool IsListInit = false);
2925
2926	/// Check for overflow behavior type related implicit conversion diagnostics.
2927	/// Returns true if OBT-related diagnostic was issued, false otherwise.
2928	bool CheckOverflowBehaviorTypeConversion(Expr *E, QualType T,
2929	SourceLocation CC);
2930
2931	bool
2932	BuiltinElementwiseTernaryMath(CallExpr *TheCall,
2933	EltwiseBuiltinArgTyRestriction ArgTyRestr =
2934	EltwiseBuiltinArgTyRestriction::FloatTy);
2935	bool PrepareBuiltinElementwiseMathOneArgCall(
2936	CallExpr *TheCall, EltwiseBuiltinArgTyRestriction ArgTyRestr =
2937	EltwiseBuiltinArgTyRestriction::None);
2938
2939	private:
2940	void CheckArrayAccess(const Expr BaseExpr, const* Expr *IndexExpr,
2941	const ArraySubscriptExpr ASE = nullptr*,
2942	bool AllowOnePastEnd = true, bool IndexNegated = false);
2943	void CheckArrayAccess(const Expr *E);
2944
2945	bool CheckPointerCall(NamedDecl NDecl, CallExpr TheCall,
2946	const FunctionProtoType *Proto);
2947
2948	/// Checks function calls when a FunctionDecl or a NamedDecl is not available,
2949	/// such as function pointers returned from functions.
2950	bool CheckOtherCall(CallExpr TheCall, const* FunctionProtoType *Proto);
2951
2952	/// CheckConstructorCall - Check a constructor call for correctness and safety
2953	/// properties not enforced by the C type system.
2954	void CheckConstructorCall(FunctionDecl *FDecl, QualType ThisType,
2955	ArrayRef<const Expr *> Args,
2956	const FunctionProtoType *Proto, SourceLocation Loc);
2957
2958	/// Warn if a pointer or reference argument passed to a function points to an
2959	/// object that is less aligned than the parameter. This can happen when
2960	/// creating a typedef with a lower alignment than the original type and then
2961	/// calling functions defined in terms of the original type.
2962	void CheckArgAlignment(SourceLocation Loc, NamedDecl *FDecl,
2963	StringRef ParamName, QualType ArgTy, QualType ParamTy);
2964
2965	ExprResult CheckOSLogFormatStringArg(Expr *Arg);
2966
2967	ExprResult CheckBuiltinFunctionCall(FunctionDecl FDecl, unsigned* BuiltinID,
2968	CallExpr *TheCall);
2969
2970	bool CheckTSBuiltinFunctionCall(const TargetInfo &TI, unsigned BuiltinID,
2971	CallExpr *TheCall);
2972
2973	void checkFortifiedBuiltinMemoryFunction(FunctionDecl FD, CallExpr TheCall);
2974
2975	/// Check the arguments to '__builtin_va_start', '__builtin_ms_va_start',
2976	/// or '__builtin_c23_va_start' for validity. Emit an error and return true
2977	/// on failure; return false on success.
2978	bool BuiltinVAStart(unsigned BuiltinID, CallExpr *TheCall);
2979	bool BuiltinVAStartARMMicrosoft(CallExpr *Call);
2980
2981	/// BuiltinUnorderedCompare - Handle functions like __builtin_isgreater and
2982	/// friends. This is declared to take (...), so we have to check everything.
2983	bool BuiltinUnorderedCompare(CallExpr TheCall, unsigned* BuiltinID);
2984
2985	/// BuiltinSemaBuiltinFPClassification - Handle functions like
2986	/// __builtin_isnan and friends. This is declared to take (...), so we have
2987	/// to check everything.
2988	bool BuiltinFPClassification(CallExpr TheCall, unsigned* NumArgs,
2989	unsigned BuiltinID);
2990
2991	/// Perform semantic analysis for a call to __builtin_complex.
2992	bool BuiltinComplex(CallExpr *TheCall);
2993	bool BuiltinOSLogFormat(CallExpr *TheCall);
2994
2995	/// BuiltinPrefetch - Handle __builtin_prefetch.
2996	/// This is declared to take (const void, ...) and can take two*
2997	/// optional constant int args.
2998	bool BuiltinPrefetch(CallExpr *TheCall);
2999
3000	/// Handle __builtin_alloca_with_align. This is declared
3001	/// as (size_t, size_t) where the second size_t must be a power of 2 greater
3002	/// than 8.
3003	bool BuiltinAllocaWithAlign(CallExpr *TheCall);
3004
3005	/// BuiltinArithmeticFence - Handle __arithmetic_fence.
3006	bool BuiltinArithmeticFence(CallExpr *TheCall);
3007
3008	/// BuiltinAssume - Handle __assume (MS Extension).
3009	/// __assume does not evaluate its arguments, and should warn if its argument
3010	/// has side effects.
3011	bool BuiltinAssume(CallExpr *TheCall);
3012
3013	/// Handle __builtin_assume_aligned. This is declared
3014	/// as (const void, size_t, ...) and can take one optional constant int arg.*
3015	bool BuiltinAssumeAligned(CallExpr *TheCall);
3016
3017	/// BuiltinLongjmp - Handle __builtin_longjmp(void env[5], int val).*
3018	/// This checks that the target supports __builtin_longjmp and
3019	/// that val is a constant 1.
3020	bool BuiltinLongjmp(CallExpr *TheCall);
3021
3022	/// BuiltinSetjmp - Handle __builtin_setjmp(void env[5]).*
3023	/// This checks that the target supports __builtin_setjmp.
3024	bool BuiltinSetjmp(CallExpr *TheCall);
3025
3026	/// We have a call to a function like __sync_fetch_and_add, which is an
3027	/// overloaded function based on the pointer type of its first argument.
3028	/// The main BuildCallExpr routines have already promoted the types of
3029	/// arguments because all of these calls are prototyped as void(...).
3030	///
3031	/// This function goes through and does final semantic checking for these
3032	/// builtins, as well as generating any warnings.
3033	ExprResult BuiltinAtomicOverloaded(ExprResult TheCallResult);
3034
3035	/// BuiltinNontemporalOverloaded - We have a call to
3036	/// __builtin_nontemporal_store or __builtin_nontemporal_load, which is an
3037	/// overloaded function based on the pointer type of its last argument.
3038	///
3039	/// This function goes through and does final semantic checking for these
3040	/// builtins.
3041	ExprResult BuiltinNontemporalOverloaded(ExprResult TheCallResult);
3042	ExprResult AtomicOpsOverloaded(ExprResult TheCallResult,
3043	AtomicExpr::AtomicOp Op);
3044
3045	/// \param FPOnly restricts the arguments to floating-point types.
3046	bool BuiltinElementwiseMath(CallExpr *TheCall,
3047	EltwiseBuiltinArgTyRestriction ArgTyRestr =
3048	EltwiseBuiltinArgTyRestriction::None);
3049	bool PrepareBuiltinReduceMathOneArgCall(CallExpr *TheCall);
3050
3051	bool BuiltinNonDeterministicValue(CallExpr *TheCall);
3052
3053	bool CheckInvalidBuiltinCountedByRef(const Expr *E,
3054	BuiltinCountedByRefKind K);
3055	bool BuiltinCountedByRef(CallExpr *TheCall);
3056
3057	// Matrix builtin handling.
3058	ExprResult BuiltinMatrixTranspose(CallExpr *TheCall, ExprResult CallResult);
3059	ExprResult BuiltinMatrixColumnMajorLoad(CallExpr *TheCall,
3060	ExprResult CallResult);
3061	ExprResult BuiltinMatrixColumnMajorStore(CallExpr *TheCall,
3062	ExprResult CallResult);
3063
3064	/// CheckFormatArguments - Check calls to printf and scanf (and similar
3065	/// functions) for correct use of format strings.
3066	/// Returns true if a format string has been fully checked.
3067	bool CheckFormatArguments(const FormatAttr *Format,
3068	ArrayRef<const Expr > Args, bool* IsCXXMember,
3069	VariadicCallType CallType, SourceLocation Loc,
3070	SourceRange Range,
3071	llvm::SmallBitVector &CheckedVarArgs);
3072	bool CheckFormatString(const FormatMatchesAttr *Format,
3073	ArrayRef<const Expr > Args, bool* IsCXXMember,
3074	VariadicCallType CallType, SourceLocation Loc,
3075	SourceRange Range,
3076	llvm::SmallBitVector &CheckedVarArgs);
3077	bool CheckFormatArguments(ArrayRef<const Expr *> Args,
3078	FormatArgumentPassingKind FAPK,
3079	StringLiteral *ReferenceFormatString,
3080	unsigned format_idx, unsigned firstDataArg,
3081	FormatStringType Type, VariadicCallType CallType,
3082	SourceLocation Loc, SourceRange range,
3083	llvm::SmallBitVector &CheckedVarArgs);
3084
3085	void CheckInfNaNFunction(const CallExpr Call, const* FunctionDecl *FDecl);
3086
3087	/// Warn when using the wrong abs() function.
3088	void CheckAbsoluteValueFunction(const CallExpr *Call,
3089	const FunctionDecl *FDecl);
3090
3091	void CheckMaxUnsignedZero(const CallExpr Call, const* FunctionDecl *FDecl);
3092
3093	/// Check for dangerous or invalid arguments to memset().
3094	///
3095	/// This issues warnings on known problematic, dangerous or unspecified
3096	/// arguments to the standard 'memset', 'memcpy', 'memmove', and 'memcmp'
3097	/// function calls.
3098	///
3099	/// \param Call The call expression to diagnose.
3100	void CheckMemaccessArguments(const CallExpr Call, unsigned* BId,
3101	IdentifierInfo *FnName);
3102
3103	bool CheckSizeofMemaccessArgument(const Expr SizeOfArg, const* Expr *Dest,
3104	IdentifierInfo *FnName);
3105	// Warn if the user has made the 'size' argument to strlcpy or strlcat
3106	// be the size of the source, instead of the destination.
3107	void CheckStrlcpycatArguments(const CallExpr Call, IdentifierInfo FnName);
3108
3109	// Warn on anti-patterns as the 'size' argument to strncat.
3110	// The correct size argument should look like following:
3111	// strncat(dst, src, sizeof(dst) - strlen(dest) - 1);
3112	void CheckStrncatArguments(const CallExpr *Call,
3113	const IdentifierInfo *FnName);
3114
3115	/// Alerts the user that they are attempting to free a non-malloc'd object.
3116	void CheckFreeArguments(const CallExpr *E);
3117
3118	void CheckReturnValExpr(Expr *RetValExp, QualType lhsType,
3119	SourceLocation ReturnLoc, bool isObjCMethod = false,
3120	const AttrVec Attrs = nullptr*,
3121	const FunctionDecl FD = nullptr*);
3122
3123	/// Diagnoses "dangerous" implicit conversions within the given
3124	/// expression (which is a full expression). Implements -Wconversion
3125	/// and -Wsign-compare.
3126	///
3127	/// \param CC the "context" location of the implicit conversion, i.e.
3128	/// the most location of the syntactic entity requiring the implicit
3129	/// conversion
3130	void CheckImplicitConversions(Expr *E, SourceLocation CC = SourceLocation ());
3131
3132	/// CheckBoolLikeConversion - Check conversion of given expression to boolean.
3133	/// Input argument E is a logical expression.
3134	void CheckBoolLikeConversion(Expr *E, SourceLocation CC);
3135
3136	/// Diagnose when expression is an integer constant expression and its
3137	/// evaluation results in integer overflow
3138	void CheckForIntOverflow(const Expr *E);
3139	void CheckUnsequencedOperations(const Expr *E);
3140
3141	/// Perform semantic checks on a completed expression. This will either
3142	/// be a full-expression or a default argument expression.
3143	void CheckCompletedExpr(Expr *E, SourceLocation CheckLoc = SourceLocation (),
3144	bool IsConstexpr = false);
3145
3146	void CheckBitFieldInitialization(SourceLocation InitLoc, FieldDecl *Field,
3147	Expr *Init);
3148
3149	/// A map from magic value to type information.
3150	std::unique_ptr<llvm::DenseMap<TypeTagMagicValue, TypeTagData>>
3151	TypeTagForDatatypeMagicValues;
3152
3153	/// Peform checks on a call of a function with argument_with_type_tag
3154	/// or pointer_with_type_tag attributes.
3155	void CheckArgumentWithTypeTag(const ArgumentWithTypeTagAttr *Attr,
3156	const ArrayRef<const Expr *> ExprArgs,
3157	SourceLocation CallSiteLoc);
3158
3159	/// Check if we are taking the address of a packed field
3160	/// as this may be a problem if the pointer value is dereferenced.
3161	void CheckAddressOfPackedMember(Expr *rhs);
3162
3163	/// Helper class that collects misaligned member designations and
3164	/// their location info for delayed diagnostics.
3165	struct MisalignedMember {
3166	Expr *E;
3167	RecordDecl *RD;
3168	ValueDecl *MD;
3169	CharUnits Alignment;
3170
3171	MisalignedMember() : E(), RD(), MD() {}
3172	MisalignedMember(Expr E, RecordDecl RD, ValueDecl *MD,
3173	CharUnits Alignment)
3174	: E(E), RD(RD), MD(MD), Alignment (Alignment) {}
3175	explicit MisalignedMember(Expr *E)
3176	: MisalignedMember (E, nullptr, nullptr, CharUnits ()) {}
3177
3178	bool operator==(const MisalignedMember &m) { return this->E == m.E; }
3179	};
3180
3181	/// Adds an expression to the set of gathered misaligned members.
3182	void AddPotentialMisalignedMembers(Expr E, RecordDecl RD, ValueDecl *MD,
3183	CharUnits Alignment);
3184	///@}
3185
3186	//
3187	//
3188	// -------------------------------------------------------------------------
3189	//
3190	//
3191
3192	/// \name C++ Coroutines
3193	/// Implementations are in SemaCoroutine.cpp
3194	///@{
3195
3196	public:
3197	/// The C++ "std::coroutine_traits" template, which is defined in
3198	/// \<coroutine_traits>
3199	ClassTemplateDecl *StdCoroutineTraitsCache;
3200
3201	bool ActOnCoroutineBodyStart(Scope *S, SourceLocation KwLoc,
3202	StringRef Keyword);
3203	ExprResult ActOnCoawaitExpr(Scope S, SourceLocation KwLoc, Expr E);
3204	ExprResult ActOnCoyieldExpr(Scope S, SourceLocation KwLoc, Expr E);
3205	StmtResult ActOnCoreturnStmt(Scope S, SourceLocation KwLoc, Expr E);
3206
3207	ExprResult BuildOperatorCoawaitLookupExpr(Scope *S, SourceLocation Loc);
3208	ExprResult BuildOperatorCoawaitCall(SourceLocation Loc, Expr *E,
3209	UnresolvedLookupExpr *Lookup);
3210	ExprResult BuildResolvedCoawaitExpr(SourceLocation KwLoc, Expr *Operand,
3211	Expr Awaiter, bool* IsImplicit = false);
3212	ExprResult BuildUnresolvedCoawaitExpr(SourceLocation KwLoc, Expr *Operand,
3213	UnresolvedLookupExpr *Lookup);
3214	ExprResult BuildCoyieldExpr(SourceLocation KwLoc, Expr *E);
3215	StmtResult BuildCoreturnStmt(SourceLocation KwLoc, Expr *E,
3216	bool IsImplicit = false);
3217	StmtResult BuildCoroutineBodyStmt(CoroutineBodyStmt::CtorArgs);
3218	bool buildCoroutineParameterMoves(SourceLocation Loc);
3219	VarDecl *buildCoroutinePromise(SourceLocation Loc);
3220	void CheckCompletedCoroutineBody(FunctionDecl FD, Stmt &Body);
3221
3222	// As a clang extension, enforces that a non-coroutine function must be marked
3223	// with [[clang::coro_wrapper]] if it returns a type marked with
3224	// [[clang::coro_return_type]].
3225	// Expects that FD is not a coroutine.
3226	void CheckCoroutineWrapper(FunctionDecl *FD);
3227	/// Lookup 'coroutine_traits' in std namespace and std::experimental
3228	/// namespace. The namespace found is recorded in Namespace.
3229	ClassTemplateDecl *lookupCoroutineTraits(SourceLocation KwLoc,
3230	SourceLocation FuncLoc);
3231	/// Check that the expression co_await promise.final_suspend() shall not be
3232	/// potentially-throwing.
3233	bool checkFinalSuspendNoThrow(const Stmt *FinalSuspend);
3234
3235	///@}
3236
3237	//
3238	//
3239	// -------------------------------------------------------------------------
3240	//
3241	//
3242
3243	/// \name C++ Scope Specifiers
3244	/// Implementations are in SemaCXXScopeSpec.cpp
3245	///@{
3246
3247	public:
3248	// Marks SS invalid if it represents an incomplete type.
3249	bool RequireCompleteDeclContext(CXXScopeSpec &SS, DeclContext *DC);
3250	// Complete an enum decl, maybe without a scope spec.
3251	bool RequireCompleteEnumDecl(EnumDecl *D, SourceLocation L,
3252	CXXScopeSpec SS = nullptr*);
3253
3254	/// Compute the DeclContext that is associated with the given type.
3255	///
3256	/// \param T the type for which we are attempting to find a DeclContext.
3257	///
3258	/// \returns the declaration context represented by the type T,
3259	/// or NULL if the declaration context cannot be computed (e.g., because it is
3260	/// dependent and not the current instantiation).
3261	DeclContext *computeDeclContext(QualType T);
3262
3263	/// Compute the DeclContext that is associated with the given
3264	/// scope specifier.
3265	///
3266	/// \param SS the C++ scope specifier as it appears in the source
3267	///
3268	/// \param EnteringContext when true, we will be entering the context of
3269	/// this scope specifier, so we can retrieve the declaration context of a
3270	/// class template or class template partial specialization even if it is
3271	/// not the current instantiation.
3272	///
3273	/// \returns the declaration context represented by the scope specifier @p SS,
3274	/// or NULL if the declaration context cannot be computed (e.g., because it is
3275	/// dependent and not the current instantiation).
3276	DeclContext computeDeclContext(const* CXXScopeSpec &SS,
3277	bool EnteringContext = false);
3278	bool isDependentScopeSpecifier(const CXXScopeSpec &SS);
3279
3280	/// If the given nested name specifier refers to the current
3281	/// instantiation, return the declaration that corresponds to that
3282	/// current instantiation (C++0x [temp.dep.type]p1).
3283	///
3284	/// \param NNS a dependent nested name specifier.
3285	CXXRecordDecl *getCurrentInstantiationOf(NestedNameSpecifier NNS);
3286
3287	/// The parser has parsed a global nested-name-specifier '::'.
3288	///
3289	/// \param CCLoc The location of the '::'.
3290	///
3291	/// \param SS The nested-name-specifier, which will be updated in-place
3292	/// to reflect the parsed nested-name-specifier.
3293	///
3294	/// \returns true if an error occurred, false otherwise.
3295	bool ActOnCXXGlobalScopeSpecifier(SourceLocation CCLoc, CXXScopeSpec &SS);
3296
3297	/// The parser has parsed a '__super' nested-name-specifier.
3298	///
3299	/// \param SuperLoc The location of the '__super' keyword.
3300	///
3301	/// \param ColonColonLoc The location of the '::'.
3302	///
3303	/// \param SS The nested-name-specifier, which will be updated in-place
3304	/// to reflect the parsed nested-name-specifier.
3305	///
3306	/// \returns true if an error occurred, false otherwise.
3307	bool ActOnSuperScopeSpecifier(SourceLocation SuperLoc,
3308	SourceLocation ColonColonLoc, CXXScopeSpec &SS);
3309
3310	/// Determines whether the given declaration is an valid acceptable
3311	/// result for name lookup of a nested-name-specifier.
3312	/// \param SD Declaration checked for nested-name-specifier.
3313	/// \param IsExtension If not null and the declaration is accepted as an
3314	/// extension, the pointed variable is assigned true.
3315	bool isAcceptableNestedNameSpecifier(const NamedDecl *SD,
3316	bool CanCorrect = nullptr*);
3317
3318	/// If the given nested-name-specifier begins with a bare identifier
3319	/// (e.g., Base::), perform name lookup for that identifier as a
3320	/// nested-name-specifier within the given scope, and return the result of
3321	/// that name lookup.
3322	NamedDecl FindFirstQualifierInScope(Scope S, NestedNameSpecifier NNS);
3323
3324	/// Keeps information about an identifier in a nested-name-spec.
3325	///
3326	struct NestedNameSpecInfo {
3327	/// The type of the object, if we're parsing nested-name-specifier in
3328	/// a member access expression.
3329	ParsedType ObjectType;
3330
3331	/// The identifier preceding the '::'.
3332	IdentifierInfo *Identifier;
3333
3334	/// The location of the identifier.
3335	SourceLocation IdentifierLoc;
3336
3337	/// The location of the '::'.
3338	SourceLocation CCLoc;
3339
3340	/// Creates info object for the most typical case.
3341	NestedNameSpecInfo(IdentifierInfo *II, SourceLocation IdLoc,
3342	SourceLocation ColonColonLoc,
3343	ParsedType ObjectType = ParsedType ())
3344	: ObjectType (ObjectType), Identifier(II), IdentifierLoc (IdLoc),
3345	CCLoc (ColonColonLoc) {}
3346
3347	NestedNameSpecInfo(IdentifierInfo *II, SourceLocation IdLoc,
3348	SourceLocation ColonColonLoc, QualType ObjectType)
3349	: ObjectType(ParsedType::make(P: ObjectType)), Identifier(II),
3350	IdentifierLoc (IdLoc), CCLoc (ColonColonLoc) {}
3351	};
3352
3353	/// Build a new nested-name-specifier for "identifier::", as described
3354	/// by ActOnCXXNestedNameSpecifier.
3355	///
3356	/// \param S Scope in which the nested-name-specifier occurs.
3357	/// \param IdInfo Parser information about an identifier in the
3358	/// nested-name-spec.
3359	/// \param EnteringContext If true, enter the context specified by the
3360	/// nested-name-specifier.
3361	/// \param SS Optional nested name specifier preceding the identifier.
3362	/// \param ScopeLookupResult Provides the result of name lookup within the
3363	/// scope of the nested-name-specifier that was computed at template
3364	/// definition time.
3365	/// \param ErrorRecoveryLookup Specifies if the method is called to improve
3366	/// error recovery and what kind of recovery is performed.
3367	/// \param IsCorrectedToColon If not null, suggestion of replace '::' -> ':'
3368	/// are allowed. The bool value pointed by this parameter is set to
3369	/// 'true' if the identifier is treated as if it was followed by ':',
3370	/// not '::'.
3371	/// \param OnlyNamespace If true, only considers namespaces in lookup.
3372	///
3373	/// This routine differs only slightly from ActOnCXXNestedNameSpecifier, in
3374	/// that it contains an extra parameter \p ScopeLookupResult, which provides
3375	/// the result of name lookup within the scope of the nested-name-specifier
3376	/// that was computed at template definition time.
3377	///
3378	/// If ErrorRecoveryLookup is true, then this call is used to improve error
3379	/// recovery. This means that it should not emit diagnostics, it should
3380	/// just return true on failure. It also means it should only return a valid
3381	/// scope if it knows* that the result is correct. It should not return in a*
3382	/// dependent context, for example. Nor will it extend \p SS with the scope
3383	/// specifier.
3384	bool BuildCXXNestedNameSpecifier(Scope *S, NestedNameSpecInfo &IdInfo,
3385	bool EnteringContext, CXXScopeSpec &SS,
3386	NamedDecl *ScopeLookupResult,
3387	bool ErrorRecoveryLookup,
3388	bool IsCorrectedToColon = nullptr*,
3389	bool OnlyNamespace = false);
3390
3391	/// The parser has parsed a nested-name-specifier 'identifier::'.
3392	///
3393	/// \param S The scope in which this nested-name-specifier occurs.
3394	///
3395	/// \param IdInfo Parser information about an identifier in the
3396	/// nested-name-spec.
3397	///
3398	/// \param EnteringContext Whether we're entering the context nominated by
3399	/// this nested-name-specifier.
3400	///
3401	/// \param SS The nested-name-specifier, which is both an input
3402	/// parameter (the nested-name-specifier before this type) and an
3403	/// output parameter (containing the full nested-name-specifier,
3404	/// including this new type).
3405	///
3406	/// \param IsCorrectedToColon If not null, suggestions to replace '::' -> ':'
3407	/// are allowed. The bool value pointed by this parameter is set to 'true'
3408	/// if the identifier is treated as if it was followed by ':', not '::'.
3409	///
3410	/// \param OnlyNamespace If true, only considers namespaces in lookup.
3411	///
3412	/// \returns true if an error occurred, false otherwise.
3413	bool ActOnCXXNestedNameSpecifier(Scope *S, NestedNameSpecInfo &IdInfo,
3414	bool EnteringContext, CXXScopeSpec &SS,
3415	bool IsCorrectedToColon = nullptr*,
3416	bool OnlyNamespace = false);
3417
3418	/// The parser has parsed a nested-name-specifier
3419	/// 'template[opt] template-name < template-args >::'.
3420	///
3421	/// \param S The scope in which this nested-name-specifier occurs.
3422	///
3423	/// \param SS The nested-name-specifier, which is both an input
3424	/// parameter (the nested-name-specifier before this type) and an
3425	/// output parameter (containing the full nested-name-specifier,
3426	/// including this new type).
3427	///
3428	/// \param TemplateKWLoc the location of the 'template' keyword, if any.
3429	/// \param TemplateName the template name.
3430	/// \param TemplateNameLoc The location of the template name.
3431	/// \param LAngleLoc The location of the opening angle bracket ('<').
3432	/// \param TemplateArgs The template arguments.
3433	/// \param RAngleLoc The location of the closing angle bracket ('>').
3434	/// \param CCLoc The location of the '::'.
3435	///
3436	/// \param EnteringContext Whether we're entering the context of the
3437	/// nested-name-specifier.
3438	///
3439	///
3440	/// \returns true if an error occurred, false otherwise.
3441	bool ActOnCXXNestedNameSpecifier(
3442	Scope *S, CXXScopeSpec &SS, SourceLocation TemplateKWLoc,
3443	TemplateTy TemplateName, SourceLocation TemplateNameLoc,
3444	SourceLocation LAngleLoc, ASTTemplateArgsPtr TemplateArgs,
3445	SourceLocation RAngleLoc, SourceLocation CCLoc, bool EnteringContext);
3446
3447	bool ActOnCXXNestedNameSpecifierDecltype(CXXScopeSpec &SS, const DeclSpec &DS,
3448	SourceLocation ColonColonLoc);
3449
3450	bool ActOnCXXNestedNameSpecifierIndexedPack(CXXScopeSpec &SS,
3451	const DeclSpec &DS,
3452	SourceLocation ColonColonLoc,
3453	QualType Type);
3454
3455	/// IsInvalidUnlessNestedName - This method is used for error recovery
3456	/// purposes to determine whether the specified identifier is only valid as
3457	/// a nested name specifier, for example a namespace name. It is
3458	/// conservatively correct to always return false from this method.
3459	///
3460	/// The arguments are the same as those passed to ActOnCXXNestedNameSpecifier.
3461	bool IsInvalidUnlessNestedName(Scope *S, CXXScopeSpec &SS,
3462	NestedNameSpecInfo &IdInfo,
3463	bool EnteringContext);
3464
3465	/// Given a C++ nested-name-specifier, produce an annotation value
3466	/// that the parser can use later to reconstruct the given
3467	/// nested-name-specifier.
3468	///
3469	/// \param SS A nested-name-specifier.
3470	///
3471	/// \returns A pointer containing all of the information in the
3472	/// nested-name-specifier \p SS.
3473	void *SaveNestedNameSpecifierAnnotation(CXXScopeSpec &SS);
3474
3475	/// Given an annotation pointer for a nested-name-specifier, restore
3476	/// the nested-name-specifier structure.
3477	///
3478	/// \param Annotation The annotation pointer, produced by
3479	/// \c SaveNestedNameSpecifierAnnotation().
3480	///
3481	/// \param AnnotationRange The source range corresponding to the annotation.
3482	///
3483	/// \param SS The nested-name-specifier that will be updated with the contents
3484	/// of the annotation pointer.
3485	void RestoreNestedNameSpecifierAnnotation(void *Annotation,
3486	SourceRange AnnotationRange,
3487	CXXScopeSpec &SS);
3488
3489	bool ShouldEnterDeclaratorScope(Scope S, const* CXXScopeSpec &SS);
3490
3491	/// ActOnCXXEnterDeclaratorScope - Called when a C++ scope specifier (global
3492	/// scope or nested-name-specifier) is parsed, part of a declarator-id.
3493	/// After this method is called, according to [C++ 3.4.3p3], names should be
3494	/// looked up in the declarator-id's scope, until the declarator is parsed and
3495	/// ActOnCXXExitDeclaratorScope is called.
3496	/// The 'SS' should be a non-empty valid CXXScopeSpec.
3497	bool ActOnCXXEnterDeclaratorScope(Scope *S, CXXScopeSpec &SS);
3498
3499	/// ActOnCXXExitDeclaratorScope - Called when a declarator that previously
3500	/// invoked ActOnCXXEnterDeclaratorScope(), is finished. 'SS' is the same
3501	/// CXXScopeSpec that was passed to ActOnCXXEnterDeclaratorScope as well.
3502	/// Used to indicate that names should revert to being looked up in the
3503	/// defining scope.
3504	void ActOnCXXExitDeclaratorScope(Scope S, const* CXXScopeSpec &SS);
3505
3506	///@}
3507
3508	//
3509	//
3510	// -------------------------------------------------------------------------
3511	//
3512	//
3513
3514	/// \name Declarations
3515	/// Implementations are in SemaDecl.cpp
3516	///@{
3517
3518	public:
3519	IdentifierResolver IdResolver;
3520
3521	/// The index of the first InventedParameterInfo that refers to the current
3522	/// context.
3523	unsigned InventedParameterInfosStart = `0`;
3524
3525	/// A RAII object to temporarily push a declaration context.
3526	class ContextRAII {
3527	private:
3528	Sema &S;
3529	DeclContext *SavedContext;
3530	ProcessingContextState SavedContextState;
3531	QualType SavedCXXThisTypeOverride;
3532	unsigned SavedFunctionScopesStart;
3533	unsigned SavedInventedParameterInfosStart;
3534
3535	public:
3536	ContextRAII(Sema &S, DeclContext ContextToPush, bool* NewThisContext = true)
3537	: S(S), SavedContext(S.CurContext),
3538	SavedContextState(S.DelayedDiagnostics.pushUndelayed()),
3539	SavedCXXThisTypeOverride (S.CXXThisTypeOverride),
3540	SavedFunctionScopesStart(S.FunctionScopesStart),
3541	SavedInventedParameterInfosStart(S.InventedParameterInfosStart) {
3542	assert(ContextToPush && "pushing null context");
3543	S.CurContext = ContextToPush;
3544	if (NewThisContext)
3545	S.CXXThisTypeOverride = QualType ();
3546	// Any saved FunctionScopes do not refer to this context.
3547	S.FunctionScopesStart = S.FunctionScopes.size();
3548	S.InventedParameterInfosStart = S.InventedParameterInfos.size();
3549	}
3550
3551	void pop() {
3552	if (!SavedContext)
3553	return;
3554	S.CurContext = SavedContext;
3555	S.DelayedDiagnostics.popUndelayed(state: SavedContextState);
3556	S.CXXThisTypeOverride = SavedCXXThisTypeOverride;
3557	S.FunctionScopesStart = SavedFunctionScopesStart;
3558	S.InventedParameterInfosStart = SavedInventedParameterInfosStart;
3559	SavedContext = nullptr;
3560	}
3561
3562	~ContextRAII() { pop(); }
3563	ContextRAII(const ContextRAII &) = delete;
3564	ContextRAII &operator=(const ContextRAII &) = delete;
3565	};
3566
3567	void DiagnoseInvalidJumps(Stmt *Body);
3568
3569	/// The function definitions which were renamed as part of typo-correction
3570	/// to match their respective declarations. We want to keep track of them
3571	/// to ensure that we don't emit a "redefinition" error if we encounter a
3572	/// correctly named definition after the renamed definition.
3573	llvm::SmallPtrSet<const NamedDecl *, `4`> TypoCorrectedFunctionDefinitions;
3574
3575	/// A cache of the flags available in enumerations with the flag_bits
3576	/// attribute.
3577	mutable llvm::DenseMap<const EnumDecl *, llvm::APInt> FlagBitsCache;
3578
3579	/// A cache of enumerator values for enums checked by -Wassign-enum.
3580	llvm::DenseMap<const EnumDecl *, llvm::SmallVector<llvm::APSInt>>
3581	AssignEnumCache;
3582
3583	/// WeakUndeclaredIdentifiers - Identifiers contained in \#pragma weak before
3584	/// declared. Rare. May alias another identifier, declared or undeclared.
3585	///
3586	/// For aliases, the target identifier is used as a key for eventual
3587	/// processing when the target is declared. For the single-identifier form,
3588	/// the sole identifier is used as the key. Each entry is a `SetVector`
3589	/// (ordered by parse order) of aliases (identified by the alias name) in case
3590	/// of multiple aliases to the same undeclared identifier.
3591	llvm::MapVector<
3592	IdentifierInfo *,
3593	llvm::SetVector<
3594	WeakInfo, llvm::SmallVector<WeakInfo, `1u`>,
3595	llvm::SmallDenseSet<WeakInfo, `2u`, WeakInfo::DenseMapInfoByAliasOnly>>>
3596	WeakUndeclaredIdentifiers;
3597
3598	/// ExtnameUndeclaredIdentifiers - Identifiers contained in
3599	/// \#pragma redefine_extname before declared. Used in Solaris system headers
3600	/// to define functions that occur in multiple standards to call the version
3601	/// in the currently selected standard.
3602	llvm::DenseMap<IdentifierInfo , AsmLabelAttr > ExtnameUndeclaredIdentifiers;
3603
3604	/// Set containing all typedefs that are likely unused.
3605	llvm::SmallSetVector<const TypedefNameDecl *, `4`>
3606	UnusedLocalTypedefNameCandidates;
3607
3608	typedef LazyVector<const DeclaratorDecl *, ExternalSemaSource,
3609	&ExternalSemaSource::ReadUnusedFileScopedDecls, `2`, `2`>
3610	UnusedFileScopedDeclsType;
3611
3612	/// The set of file scoped decls seen so far that have not been used
3613	/// and must warn if not used. Only contains the first declaration.
3614	UnusedFileScopedDeclsType UnusedFileScopedDecls;
3615
3616	typedef LazyVector<VarDecl *, ExternalSemaSource,
3617	&ExternalSemaSource::ReadTentativeDefinitions, `2`, `2`>
3618	TentativeDefinitionsType;
3619
3620	/// All the tentative definitions encountered in the TU.
3621	TentativeDefinitionsType TentativeDefinitions;
3622
3623	/// All the external declarations encoutered and used in the TU.
3624	SmallVector<DeclaratorDecl *, `4`> ExternalDeclarations;
3625
3626	/// Generally null except when we temporarily switch decl contexts,
3627	/// like in \see SemaObjC::ActOnObjCTemporaryExitContainerContext.
3628	DeclContext *OriginalLexicalContext;
3629
3630	/// Is the module scope we are in a C++ Header Unit?
3631	bool currentModuleIsHeaderUnit() const {
3632	return ModuleScopes.empty() ? false
3633	: ModuleScopes.back().Module->isHeaderUnit();
3634	}
3635
3636	/// Get the module owning an entity.
3637	Module getOwningModule(const* Decl *Entity) {
3638	return Entity->getOwningModule();
3639	}
3640
3641	DeclGroupPtrTy ConvertDeclToDeclGroup(Decl Ptr, Decl OwnedType = nullptr);
3642
3643	enum class DiagCtorKind { None, Implicit, Typename };
3644	/// Returns the TypeDeclType for the given type declaration,
3645	/// as ASTContext::getTypeDeclType would, but
3646	/// performs the required semantic checks for name lookup of said entity.
3647	void checkTypeDeclType(DeclContext LookupCtx, DiagCtorKind DCK, TypeDecl TD,
3648	SourceLocation NameLoc);
3649
3650	/// If the identifier refers to a type name within this scope,
3651	/// return the declaration of that type.
3652	///
3653	/// This routine performs ordinary name lookup of the identifier II
3654	/// within the given scope, with optional C++ scope specifier SS, to
3655	/// determine whether the name refers to a type. If so, returns an
3656	/// opaque pointer (actually a QualType) corresponding to that
3657	/// type. Otherwise, returns NULL.
3658	ParsedType getTypeName(const IdentifierInfo &II, SourceLocation NameLoc,
3659	Scope S, CXXScopeSpec SS = nullptr,
3660	bool isClassName = false, bool HasTrailingDot = false,
3661	ParsedType ObjectType = nullptr,
3662	bool IsCtorOrDtorName = false,
3663	bool WantNontrivialTypeSourceInfo = false,
3664	bool IsClassTemplateDeductionContext = true,
3665	ImplicitTypenameContext AllowImplicitTypename =
3666	ImplicitTypenameContext::No,
3667	IdentifierInfo CorrectedII = nullptr**);
3668
3669	/// isTagName() - This method is called for error recovery purposes only
3670	/// to determine if the specified name is a valid tag name ("struct foo"). If
3671	/// so, this returns the TST for the tag corresponding to it (TST_enum,
3672	/// TST_union, TST_struct, TST_interface, TST_class). This is used to
3673	/// diagnose cases in C where the user forgot to specify the tag.
3674	TypeSpecifierType isTagName(IdentifierInfo &II, Scope *S);
3675
3676	/// isMicrosoftMissingTypename - In Microsoft mode, within class scope,
3677	/// if a CXXScopeSpec's type is equal to the type of one of the base classes
3678	/// then downgrade the missing typename error to a warning.
3679	/// This is needed for MSVC compatibility; Example:
3680	/// @code
3681	/// template<class T> class A {
3682	/// public:
3683	/// typedef int TYPE;
3684	/// };
3685	/// template<class T> class B : public A<T> {
3686	/// public:
3687	/// A<T>::TYPE a; // no typename required because A<T> is a base class.
3688	/// };
3689	/// @endcode
3690	bool isMicrosoftMissingTypename(const CXXScopeSpec SS, Scope S);
3691	void DiagnoseUnknownTypeName(IdentifierInfo *&II, SourceLocation IILoc,
3692	Scope S, CXXScopeSpec SS,
3693	ParsedType &SuggestedType,
3694	bool IsTemplateName = false);
3695
3696	/// Attempt to behave like MSVC in situations where lookup of an unqualified
3697	/// type name has failed in a dependent context. In these situations, we
3698	/// automatically form a DependentTypeName that will retry lookup in a related
3699	/// scope during instantiation.
3700	ParsedType ActOnMSVCUnknownTypeName(const IdentifierInfo &II,
3701	SourceLocation NameLoc,
3702	bool IsTemplateTypeArg);
3703
3704	class NameClassification {
3705	NameClassificationKind Kind;
3706	union {
3707	ExprResult Expr;
3708	NamedDecl *NonTypeDecl;
3709	TemplateName Template;
3710	ParsedType Type;
3711	};
3712
3713	explicit NameClassification(NameClassificationKind Kind) : Kind(Kind) {}
3714
3715	public:
3716	NameClassification(ParsedType Type)
3717	: Kind(NameClassificationKind::Type), Type (Type) {}
3718
3719	NameClassification(const IdentifierInfo *Keyword)
3720	: Kind(NameClassificationKind::Keyword) {}
3721
3722	static NameClassification Error() {
3723	return NameClassification (NameClassificationKind::Error);
3724	}
3725
3726	static NameClassification Unknown() {
3727	return NameClassification (NameClassificationKind::Unknown);
3728	}
3729
3730	static NameClassification OverloadSet(ExprResult E) {
3731	NameClassification Result(NameClassificationKind::OverloadSet);
3732	Result.Expr = E;
3733	return Result;
3734	}
3735
3736	static NameClassification NonType(NamedDecl *D) {
3737	NameClassification Result(NameClassificationKind::NonType);
3738	Result.NonTypeDecl = D;
3739	return Result;
3740	}
3741
3742	static NameClassification UndeclaredNonType() {
3743	return NameClassification (NameClassificationKind::UndeclaredNonType);
3744	}
3745
3746	static NameClassification DependentNonType() {
3747	return NameClassification (NameClassificationKind::DependentNonType);
3748	}
3749
3750	static NameClassification TypeTemplate(TemplateName Name) {
3751	NameClassification Result(NameClassificationKind::TypeTemplate);
3752	Result.Template = Name;
3753	return Result;
3754	}
3755
3756	static NameClassification VarTemplate(TemplateName Name) {
3757	NameClassification Result(NameClassificationKind::VarTemplate);
3758	Result.Template = Name;
3759	return Result;
3760	}
3761
3762	static NameClassification FunctionTemplate(TemplateName Name) {
3763	NameClassification Result(NameClassificationKind::FunctionTemplate);
3764	Result.Template = Name;
3765	return Result;
3766	}
3767
3768	static NameClassification Concept(TemplateName Name) {
3769	NameClassification Result(NameClassificationKind::Concept);
3770	Result.Template = Name;
3771	return Result;
3772	}
3773
3774	static NameClassification UndeclaredTemplate(TemplateName Name) {
3775	NameClassification Result(NameClassificationKind::UndeclaredTemplate);
3776	Result.Template = Name;
3777	return Result;
3778	}
3779
3780	NameClassificationKind getKind() const { return Kind; }
3781
3782	ExprResult getExpression() const {
3783	assert(Kind == NameClassificationKind::OverloadSet);
3784	return Expr;
3785	}
3786
3787	ParsedType getType() const {
3788	assert(Kind == NameClassificationKind::Type);
3789	return Type;
3790	}
3791
3792	NamedDecl getNonTypeDecl() const* {
3793	assert(Kind == NameClassificationKind::NonType);
3794	return NonTypeDecl;
3795	}
3796
3797	TemplateName getTemplateName() const {
3798	assert(Kind == NameClassificationKind::TypeTemplate \|\|
3799	Kind == NameClassificationKind::FunctionTemplate \|\|
3800	Kind == NameClassificationKind::VarTemplate \|\|
3801	Kind == NameClassificationKind::Concept \|\|
3802	Kind == NameClassificationKind::UndeclaredTemplate);
3803	return Template;
3804	}
3805
3806	TemplateNameKind getTemplateNameKind() const {
3807	switch (Kind) {
3808	case NameClassificationKind::TypeTemplate:
3809	return TNK_Type_template;
3810	case NameClassificationKind::FunctionTemplate:
3811	return TNK_Function_template;
3812	case NameClassificationKind::VarTemplate:
3813	return TNK_Var_template;
3814	case NameClassificationKind::Concept:
3815	return TNK_Concept_template;
3816	case NameClassificationKind::UndeclaredTemplate:
3817	return TNK_Undeclared_template;
3818	default:
3819	llvm_unreachable("unsupported name classification.");
3820	}
3821	}
3822	};
3823
3824	/// Perform name lookup on the given name, classifying it based on
3825	/// the results of name lookup and the following token.
3826	///
3827	/// This routine is used by the parser to resolve identifiers and help direct
3828	/// parsing. When the identifier cannot be found, this routine will attempt
3829	/// to correct the typo and classify based on the resulting name.
3830	///
3831	/// \param S The scope in which we're performing name lookup.
3832	///
3833	/// \param SS The nested-name-specifier that precedes the name.
3834	///
3835	/// \param Name The identifier. If typo correction finds an alternative name,
3836	/// this pointer parameter will be updated accordingly.
3837	///
3838	/// \param NameLoc The location of the identifier.
3839	///
3840	/// \param NextToken The token following the identifier. Used to help
3841	/// disambiguate the name.
3842	///
3843	/// \param CCC The correction callback, if typo correction is desired.
3844	NameClassification ClassifyName(Scope *S, CXXScopeSpec &SS,
3845	IdentifierInfo *&Name, SourceLocation NameLoc,
3846	const Token &NextToken,
3847	CorrectionCandidateCallback CCC = nullptr*);
3848
3849	/// Act on the result of classifying a name as an undeclared (ADL-only)
3850	/// non-type declaration.
3851	ExprResult ActOnNameClassifiedAsUndeclaredNonType(IdentifierInfo *Name,
3852	SourceLocation NameLoc);
3853	/// Act on the result of classifying a name as an undeclared member of a
3854	/// dependent base class.
3855	ExprResult ActOnNameClassifiedAsDependentNonType(const CXXScopeSpec &SS,
3856	IdentifierInfo *Name,
3857	SourceLocation NameLoc,
3858	bool IsAddressOfOperand);
3859	/// Act on the result of classifying a name as a specific non-type
3860	/// declaration.
3861	ExprResult ActOnNameClassifiedAsNonType(Scope S, const* CXXScopeSpec &SS,
3862	NamedDecl *Found,
3863	SourceLocation NameLoc,
3864	const Token &NextToken);
3865	/// Act on the result of classifying a name as an overload set.
3866	ExprResult ActOnNameClassifiedAsOverloadSet(Scope S, Expr OverloadSet);
3867
3868	/// Describes the detailed kind of a template name. Used in diagnostics.
3869	enum class TemplateNameKindForDiagnostics {
3870	ClassTemplate,
3871	FunctionTemplate,
3872	VarTemplate,
3873	AliasTemplate,
3874	TemplateTemplateParam,
3875	Concept,
3876	DependentTemplate
3877	};
3878	TemplateNameKindForDiagnostics
3879	getTemplateNameKindForDiagnostics(TemplateName Name);
3880
3881	/// Determine whether it's plausible that E was intended to be a
3882	/// template-name.
3883	bool mightBeIntendedToBeTemplateName(ExprResult E, bool &Dependent) {
3884	if (!getLangOpts().CPlusPlus \|\| E.isInvalid())
3885	return false;
3886	Dependent = false;
3887	if (auto *DRE = dyn_cast<DeclRefExpr>(Val: E.get()))
3888	return !DRE->hasExplicitTemplateArgs();
3889	if (auto *ME = dyn_cast<MemberExpr>(Val: E.get()))
3890	return !ME->hasExplicitTemplateArgs();
3891	Dependent = true;
3892	if (auto *DSDRE = dyn_cast<DependentScopeDeclRefExpr>(Val: E.get()))
3893	return !DSDRE->hasExplicitTemplateArgs();
3894	if (auto *DSME = dyn_cast<CXXDependentScopeMemberExpr>(Val: E.get()))
3895	return !DSME->hasExplicitTemplateArgs();
3896	// Any additional cases recognized here should also be handled by
3897	// diagnoseExprIntendedAsTemplateName.
3898	return false;
3899	}
3900
3901	void warnOnReservedIdentifier(const NamedDecl *D);
3902	void warnOnCTypeHiddenInCPlusPlus(const NamedDecl *D);
3903
3904	void ProcessPragmaExport(DeclaratorDecl *newDecl);
3905
3906	Decl ActOnDeclarator(Scope S, Declarator &D);
3907
3908	NamedDecl HandleDeclarator(Scope S, Declarator &D,
3909	MultiTemplateParamsArg TemplateParameterLists);
3910
3911	/// Attempt to fold a variable-sized type to a constant-sized type, returning
3912	/// true if we were successful.
3913	bool tryToFixVariablyModifiedVarType(TypeSourceInfo *&TInfo, QualType &T,
3914	SourceLocation Loc,
3915	unsigned FailedFoldDiagID);
3916
3917	/// Register the given locally-scoped extern "C" declaration so
3918	/// that it can be found later for redeclarations. We include any extern "C"
3919	/// declaration that is not visible in the translation unit here, not just
3920	/// function-scope declarations.
3921	void RegisterLocallyScopedExternCDecl(NamedDecl ND, Scope S);
3922
3923	/// DiagnoseClassNameShadow - Implement C++ [class.mem]p13:
3924	/// If T is the name of a class, then each of the following shall have a
3925	/// name different from T:
3926	/// - every static data member of class T;
3927	/// - every member function of class T
3928	/// - every member of class T that is itself a type;
3929	/// \returns true if the declaration name violates these rules.
3930	bool DiagnoseClassNameShadow(DeclContext *DC, DeclarationNameInfo Info);
3931
3932	/// Diagnose a declaration whose declarator-id has the given
3933	/// nested-name-specifier.
3934	///
3935	/// \param SS The nested-name-specifier of the declarator-id.
3936	///
3937	/// \param DC The declaration context to which the nested-name-specifier
3938	/// resolves.
3939	///
3940	/// \param Name The name of the entity being declared.
3941	///
3942	/// \param Loc The location of the name of the entity being declared.
3943	///
3944	/// \param IsMemberSpecialization Whether we are declaring a member
3945	/// specialization.
3946	///
3947	/// \param TemplateId The template-id, if any.
3948	///
3949	/// \returns true if we cannot safely recover from this error, false
3950	/// otherwise.
3951	bool diagnoseQualifiedDeclaration(CXXScopeSpec &SS, DeclContext *DC,
3952	DeclarationName Name, SourceLocation Loc,
3953	TemplateIdAnnotation *TemplateId,
3954	bool IsMemberSpecialization);
3955
3956	bool checkPointerAuthEnabled(SourceLocation Loc, SourceRange Range);
3957
3958	bool checkConstantPointerAuthKey(Expr keyExpr, unsigned* &key);
3959
3960	bool checkPointerAuthDiscriminatorArg(Expr *Arg, PointerAuthDiscArgKind Kind,
3961	unsigned &IntVal);
3962
3963	/// Diagnose function specifiers on a declaration of an identifier that
3964	/// does not identify a function.
3965	void DiagnoseFunctionSpecifiers(const DeclSpec &DS);
3966
3967	/// Return the declaration shadowed by the given typedef \p D, or null
3968	/// if it doesn't shadow any declaration or shadowing warnings are disabled.
3969	NamedDecl getShadowedDeclaration(const* TypedefNameDecl *D,
3970	const LookupResult &R);
3971
3972	/// Return the declaration shadowed by the given variable \p D, or null
3973	/// if it doesn't shadow any declaration or shadowing warnings are disabled.
3974	NamedDecl getShadowedDeclaration(const* VarDecl D, const* LookupResult &R);
3975
3976	/// Return the declaration shadowed by the given variable \p D, or null
3977	/// if it doesn't shadow any declaration or shadowing warnings are disabled.
3978	NamedDecl getShadowedDeclaration(const* BindingDecl *D,
3979	const LookupResult &R);
3980	/// Diagnose variable or built-in function shadowing. Implements
3981	/// -Wshadow.
3982	///
3983	/// This method is called whenever a VarDecl is added to a "useful"
3984	/// scope.
3985	///
3986	/// \param ShadowedDecl the declaration that is shadowed by the given variable
3987	/// \param R the lookup of the name
3988	void CheckShadow(NamedDecl D, NamedDecl ShadowedDecl,
3989	const LookupResult &R);
3990
3991	/// Check -Wshadow without the advantage of a previous lookup.
3992	void CheckShadow(Scope S, VarDecl D);
3993
3994	/// Warn if 'E', which is an expression that is about to be modified, refers
3995	/// to a shadowing declaration.
3996	void CheckShadowingDeclModification(Expr *E, SourceLocation Loc);
3997
3998	/// Diagnose shadowing for variables shadowed in the lambda record \p LambdaRD
3999	/// when these variables are captured by the lambda.
4000	void DiagnoseShadowingLambdaDecls(const sema::LambdaScopeInfo *LSI);
4001
4002	void handleTagNumbering(const TagDecl Tag, Scope TagScope);
4003	void setTagNameForLinkagePurposes(TagDecl *TagFromDeclSpec,
4004	TypedefNameDecl *NewTD);
4005	void CheckTypedefForVariablyModifiedType(Scope S, TypedefNameDecl D);
4006	NamedDecl ActOnTypedefDeclarator(Scope S, Declarator &D, DeclContext *DC,
4007	TypeSourceInfo *TInfo,
4008	LookupResult &Previous);
4009
4010	/// ActOnTypedefNameDecl - Perform semantic checking for a declaration which
4011	/// declares a typedef-name, either using the 'typedef' type specifier or via
4012	/// a C++0x [dcl.typedef]p2 alias-declaration: 'using T = A;'.
4013	NamedDecl ActOnTypedefNameDecl(Scope S, DeclContext DC, TypedefNameDecl D,
4014	LookupResult &Previous, bool &Redeclaration);
4015	NamedDecl ActOnVariableDeclarator(Scope S, Declarator &D, DeclContext *DC,
4016	TypeSourceInfo *TInfo,
4017	LookupResult &Previous,
4018	MultiTemplateParamsArg TemplateParamLists,
4019	bool &AddToScope,
4020	ArrayRef<BindingDecl *> Bindings = {});
4021
4022	private:
4023	// Perform a check on an AsmLabel to verify its consistency and emit
4024	// diagnostics in case of an error.
4025	void CheckAsmLabel(Scope S, Expr AsmLabelExpr, StorageClass SC,
4026	TypeSourceInfo TInfo, VarDecl );
4027
4028	public:
4029	/// Perform semantic checking on a newly-created variable
4030	/// declaration.
4031	///
4032	/// This routine performs all of the type-checking required for a
4033	/// variable declaration once it has been built. It is used both to
4034	/// check variables after they have been parsed and their declarators
4035	/// have been translated into a declaration, and to check variables
4036	/// that have been instantiated from a template.
4037	///
4038	/// Sets NewVD->isInvalidDecl() if an error was encountered.
4039	///
4040	/// Returns true if the variable declaration is a redeclaration.
4041	bool CheckVariableDeclaration(VarDecl *NewVD, LookupResult &Previous);
4042	void CheckVariableDeclarationType(VarDecl *NewVD);
4043	void CheckCompleteVariableDeclaration(VarDecl *VD);
4044
4045	NamedDecl ActOnFunctionDeclarator(Scope S, Declarator &D, DeclContext *DC,
4046	TypeSourceInfo *TInfo,
4047	LookupResult &Previous,
4048	MultiTemplateParamsArg TemplateParamLists,
4049	bool &AddToScope);
4050
4051	/// AddOverriddenMethods - See if a method overrides any in the base classes,
4052	/// and if so, check that it's a valid override and remember it.
4053	bool AddOverriddenMethods(CXXRecordDecl DC, CXXMethodDecl MD);
4054
4055	/// Perform semantic checking of a new function declaration.
4056	///
4057	/// Performs semantic analysis of the new function declaration
4058	/// NewFD. This routine performs all semantic checking that does not
4059	/// require the actual declarator involved in the declaration, and is
4060	/// used both for the declaration of functions as they are parsed
4061	/// (called via ActOnDeclarator) and for the declaration of functions
4062	/// that have been instantiated via C++ template instantiation (called
4063	/// via InstantiateDecl).
4064	///
4065	/// \param IsMemberSpecialization whether this new function declaration is
4066	/// a member specialization (that replaces any definition provided by the
4067	/// previous declaration).
4068	///
4069	/// This sets NewFD->isInvalidDecl() to true if there was an error.
4070	///
4071	/// \returns true if the function declaration is a redeclaration.
4072	bool CheckFunctionDeclaration(Scope S, FunctionDecl NewFD,
4073	LookupResult &Previous,
4074	bool IsMemberSpecialization, bool DeclIsDefn);
4075
4076	/// Checks if the new declaration declared in dependent context must be
4077	/// put in the same redeclaration chain as the specified declaration.
4078	///
4079	/// \param D Declaration that is checked.
4080	/// \param PrevDecl Previous declaration found with proper lookup method for
4081	/// the same declaration name.
4082	/// \returns True if D must be added to the redeclaration chain which PrevDecl
4083	/// belongs to.
4084	bool shouldLinkDependentDeclWithPrevious(Decl D, Decl OldDecl);
4085
4086	/// Determines if we can perform a correct type check for \p D as a
4087	/// redeclaration of \p PrevDecl. If not, we can generally still perform a
4088	/// best-effort check.
4089	///
4090	/// \param NewD The new declaration.
4091	/// \param OldD The old declaration.
4092	/// \param NewT The portion of the type of the new declaration to check.
4093	/// \param OldT The portion of the type of the old declaration to check.
4094	bool canFullyTypeCheckRedeclaration(ValueDecl NewD, ValueDecl OldD,
4095	QualType NewT, QualType OldT);
4096	void CheckMain(FunctionDecl FD, const* DeclSpec &D);
4097	void CheckMSVCRTEntryPoint(FunctionDecl *FD);
4098
4099	/// Returns an implicit CodeSegAttr if a __declspec(code_seg) is found on a
4100	/// containing class. Otherwise it will return implicit SectionAttr if the
4101	/// function is a definition and there is an active value on CodeSegStack
4102	/// (from the current #pragma code-seg value).
4103	///
4104	/// \param FD Function being declared.
4105	/// \param IsDefinition Whether it is a definition or just a declaration.
4106	/// \returns A CodeSegAttr or SectionAttr to apply to the function or
4107	/// nullptr if no attribute should be added.
4108	Attr getImplicitCodeSegOrSectionAttrForFunction(const* FunctionDecl *FD,
4109	bool IsDefinition);
4110
4111	/// Common checks for a parameter-declaration that should apply to both
4112	/// function parameters and non-type template parameters.
4113	void CheckFunctionOrTemplateParamDeclarator(Scope *S, Declarator &D);
4114
4115	/// ActOnParamDeclarator - Called from Parser::ParseFunctionDeclarator()
4116	/// to introduce parameters into function prototype scope.
4117	Decl ActOnParamDeclarator(Scope S, Declarator &D,
4118	SourceLocation ExplicitThisLoc = {});
4119
4120	/// Synthesizes a variable for a parameter arising from a
4121	/// typedef.
4122	ParmVarDecl BuildParmVarDeclForTypedef(DeclContext DC, SourceLocation Loc,
4123	QualType T);
4124	ParmVarDecl CheckParameter(DeclContext DC, SourceLocation StartLoc,
4125	SourceLocation NameLoc,
4126	const IdentifierInfo *Name, QualType T,
4127	TypeSourceInfo *TSInfo, StorageClass SC);
4128
4129	/// Emit diagnostics if the initializer or any of its explicit or
4130	/// implicitly-generated subexpressions require copying or
4131	/// default-initializing a type that is or contains a C union type that is
4132	/// non-trivial to copy or default-initialize.
4133	void checkNonTrivialCUnionInInitializer(const Expr *Init, SourceLocation Loc);
4134
4135	// These flags are passed to checkNonTrivialCUnion.
4136	enum NonTrivialCUnionKind {
4137	NTCUK_Init = `0x1`,
4138	NTCUK_Destruct = `0x2`,
4139	NTCUK_Copy = `0x4`,
4140	};
4141
4142	/// Emit diagnostics if a non-trivial C union type or a struct that contains
4143	/// a non-trivial C union is used in an invalid context.
4144	void checkNonTrivialCUnion(QualType QT, SourceLocation Loc,
4145	NonTrivialCUnionContext UseContext,
4146	unsigned NonTrivialKind);
4147
4148	/// Certain globally-unique variables might be accidentally duplicated if
4149	/// built into multiple shared libraries with hidden visibility. This can
4150	/// cause problems if the variable is mutable, its initialization is
4151	/// effectful, or its address is taken.
4152	bool GloballyUniqueObjectMightBeAccidentallyDuplicated(const VarDecl *Dcl);
4153	void DiagnoseUniqueObjectDuplication(const VarDecl *Dcl);
4154
4155	/// AddInitializerToDecl - Adds the initializer Init to the
4156	/// declaration dcl. If DirectInit is true, this is C++ direct
4157	/// initialization rather than copy initialization.
4158	void AddInitializerToDecl(Decl dcl, Expr init, bool DirectInit);
4159	void ActOnUninitializedDecl(Decl *dcl);
4160
4161	/// ActOnInitializerError - Given that there was an error parsing an
4162	/// initializer for the given declaration, try to at least re-establish
4163	/// invariants such as whether a variable's type is either dependent or
4164	/// complete.
4165	void ActOnInitializerError(Decl *Dcl);
4166
4167	void ActOnCXXForRangeDecl(Decl *D);
4168	StmtResult ActOnCXXForRangeIdentifier(Scope *S, SourceLocation IdentLoc,
4169	IdentifierInfo *Ident,
4170	ParsedAttributes &Attrs);
4171
4172	/// Check if VD needs to be dllexport/dllimport due to being in a
4173	/// dllexport/import function.
4174	void CheckStaticLocalForDllExport(VarDecl *VD);
4175	void CheckThreadLocalForLargeAlignment(VarDecl *VD);
4176
4177	/// FinalizeDeclaration - called by ParseDeclarationAfterDeclarator to perform
4178	/// any semantic actions necessary after any initializer has been attached.
4179	void FinalizeDeclaration(Decl *D);
4180	DeclGroupPtrTy FinalizeDeclaratorGroup(Scope S, const* DeclSpec &DS,
4181	ArrayRef<Decl *> Group);
4182
4183	/// BuildDeclaratorGroup - convert a list of declarations into a declaration
4184	/// group, performing any necessary semantic checking.
4185	DeclGroupPtrTy BuildDeclaratorGroup(MutableArrayRef<Decl *> Group);
4186
4187	/// Should be called on all declarations that might have attached
4188	/// documentation comments.
4189	void ActOnDocumentableDecl(Decl *D);
4190	void ActOnDocumentableDecls(ArrayRef<Decl *> Group);
4191
4192	enum class FnBodyKind {
4193	/// C++26 [dcl.fct.def.general]p1
4194	/// function-body:
4195	/// ctor-initializer[opt] compound-statement
4196	/// function-try-block
4197	Other,
4198	/// = default ;
4199	Default,
4200	/// deleted-function-body
4201	///
4202	/// deleted-function-body:
4203	/// = delete ;
4204	/// = delete ( unevaluated-string ) ;
4205	Delete
4206	};
4207
4208	void ActOnFinishKNRParamDeclarations(Scope *S, Declarator &D,
4209	SourceLocation LocAfterDecls);
4210	void CheckForFunctionRedefinition(
4211	FunctionDecl FD, const* FunctionDecl EffectiveDefinition = nullptr*,
4212	SkipBodyInfo SkipBody = nullptr*);
4213	Decl ActOnStartOfFunctionDef(Scope S, Declarator &D,
4214	MultiTemplateParamsArg TemplateParamLists,
4215	SkipBodyInfo SkipBody = nullptr*,
4216	FnBodyKind BodyKind = FnBodyKind::Other);
4217	Decl ActOnStartOfFunctionDef(Scope S, Decl *D,
4218	SkipBodyInfo SkipBody = nullptr*,
4219	FnBodyKind BodyKind = FnBodyKind::Other);
4220	void applyFunctionAttributesBeforeParsingBody(Decl *FD);
4221
4222	/// Determine whether we can delay parsing the body of a function or
4223	/// function template until it is used, assuming we don't care about emitting
4224	/// code for that function.
4225	///
4226	/// This will be \c false if we may need the body of the function in the
4227	/// middle of parsing an expression (where it's impractical to switch to
4228	/// parsing a different function), for instance, if it's constexpr in C++11
4229	/// or has an 'auto' return type in C++14. These cases are essentially bugs.
4230	bool canDelayFunctionBody(const Declarator &D);
4231
4232	/// Determine whether we can skip parsing the body of a function
4233	/// definition, assuming we don't care about analyzing its body or emitting
4234	/// code for that function.
4235	///
4236	/// This will be \c false only if we may need the body of the function in
4237	/// order to parse the rest of the program (for instance, if it is
4238	/// \c constexpr in C++11 or has an 'auto' return type in C++14).
4239	bool canSkipFunctionBody(Decl *D);
4240
4241	/// Given the set of return statements within a function body,
4242	/// compute the variables that are subject to the named return value
4243	/// optimization.
4244	///
4245	/// Each of the variables that is subject to the named return value
4246	/// optimization will be marked as NRVO variables in the AST, and any
4247	/// return statement that has a marked NRVO variable as its NRVO candidate can
4248	/// use the named return value optimization.
4249	///
4250	/// This function applies a very simplistic algorithm for NRVO: if every
4251	/// return statement in the scope of a variable has the same NRVO candidate,
4252	/// that candidate is an NRVO variable.
4253	void computeNRVO(Stmt Body, sema::FunctionScopeInfo Scope);
4254
4255	/// Performs semantic analysis at the end of a function body.
4256	///
4257	/// \param RetainFunctionScopeInfo If \c true, the client is responsible for
4258	/// releasing the associated \p FunctionScopeInfo. This is useful when
4259	/// building e.g. LambdaExprs.
4260	Decl ActOnFinishFunctionBody(Decl Decl, Stmt *Body,
4261	bool IsInstantiation = false,
4262	bool RetainFunctionScopeInfo = false);
4263	Decl ActOnSkippedFunctionBody(Decl Decl);
4264	void ActOnFinishInlineFunctionDef(FunctionDecl *D);
4265
4266	/// ActOnFinishDelayedAttribute - Invoked when we have finished parsing an
4267	/// attribute for which parsing is delayed.
4268	void ActOnFinishDelayedAttribute(Scope S, Decl D, ParsedAttributes &Attrs);
4269
4270	/// Diagnose any unused parameters in the given sequence of
4271	/// ParmVarDecl pointers.
4272	void DiagnoseUnusedParameters(ArrayRef<ParmVarDecl *> Parameters);
4273
4274	/// Diagnose whether the size of parameters or return value of a
4275	/// function or obj-c method definition is pass-by-value and larger than a
4276	/// specified threshold.
4277	void
4278	DiagnoseSizeOfParametersAndReturnValue(ArrayRef<ParmVarDecl *> Parameters,
4279	QualType ReturnTy, NamedDecl *D);
4280
4281	Decl ActOnFileScopeAsmDecl(Expr expr, SourceLocation AsmLoc,
4282	SourceLocation RParenLoc);
4283
4284	TopLevelStmtDecl ActOnStartTopLevelStmtDecl(Scope S);
4285	void ActOnFinishTopLevelStmtDecl(TopLevelStmtDecl D, Stmt Statement);
4286
4287	void ActOnPopScope(SourceLocation Loc, Scope *S);
4288
4289	/// ParsedFreeStandingDeclSpec - This method is invoked when a declspec with
4290	/// no declarator (e.g. "struct foo;") is parsed.
4291	Decl ParsedFreeStandingDeclSpec(Scope S, AccessSpecifier AS, DeclSpec &DS,
4292	const ParsedAttributesView &DeclAttrs,
4293	RecordDecl *&AnonRecord);
4294
4295	/// ParsedFreeStandingDeclSpec - This method is invoked when a declspec with
4296	/// no declarator (e.g. "struct foo;") is parsed. It also accepts template
4297	/// parameters to cope with template friend declarations.
4298	Decl ParsedFreeStandingDeclSpec(Scope S, AccessSpecifier AS, DeclSpec &DS,
4299	const ParsedAttributesView &DeclAttrs,
4300	MultiTemplateParamsArg TemplateParams,
4301	bool IsExplicitInstantiation,
4302	RecordDecl *&AnonRecord,
4303	SourceLocation EllipsisLoc = {});
4304
4305	/// BuildAnonymousStructOrUnion - Handle the declaration of an
4306	/// anonymous structure or union. Anonymous unions are a C++ feature
4307	/// (C++ [class.union]) and a C11 feature; anonymous structures
4308	/// are a C11 feature and GNU C++ extension.
4309	Decl BuildAnonymousStructOrUnion(Scope S, DeclSpec &DS, AccessSpecifier AS,
4310	RecordDecl *Record,
4311	const PrintingPolicy &Policy);
4312
4313	/// Called once it is known whether
4314	/// a tag declaration is an anonymous union or struct.
4315	void ActOnDefinedDeclarationSpecifier(Decl *D);
4316
4317	/// Emit diagnostic warnings for placeholder members.
4318	/// We can only do that after the class is fully constructed,
4319	/// as anonymous union/structs can insert placeholders
4320	/// in their parent scope (which might be a Record).
4321	void DiagPlaceholderFieldDeclDefinitions(RecordDecl *Record);
4322
4323	/// BuildMicrosoftCAnonymousStruct - Handle the declaration of an
4324	/// Microsoft C anonymous structure.
4325	/// Ref: http://msdn.microsoft.com/en-us/library/z2cx9y4f.aspx
4326	/// Example:
4327	///
4328	/// struct A { int a; };
4329	/// struct B { struct A; int b; };
4330	///
4331	/// void foo() {
4332	/// B var;
4333	/// var.a = 3;
4334	/// }
4335	Decl BuildMicrosoftCAnonymousStruct(Scope S, DeclSpec &DS,
4336	RecordDecl *Record);
4337
4338	/// Given a non-tag type declaration, returns an enum useful for indicating
4339	/// what kind of non-tag type this is.
4340	NonTagKind getNonTagTypeDeclKind(const Decl *D, TagTypeKind TTK);
4341
4342	/// Determine whether a tag with a given kind is acceptable
4343	/// as a redeclaration of the given tag declaration.
4344	///
4345	/// \returns true if the new tag kind is acceptable, false otherwise.
4346	bool isAcceptableTagRedeclaration(const TagDecl *Previous, TagTypeKind NewTag,
4347	bool isDefinition, SourceLocation NewTagLoc,
4348	const IdentifierInfo *Name);
4349
4350	/// This is invoked when we see 'struct foo' or 'struct {'. In the
4351	/// former case, Name will be non-null. In the later case, Name will be null.
4352	/// TagSpec indicates what kind of tag this is. TUK indicates whether this is
4353	/// a reference/declaration/definition of a tag.
4354	///
4355	/// \param IsTypeSpecifier \c true if this is a type-specifier (or
4356	/// trailing-type-specifier) other than one in an alias-declaration.
4357	///
4358	/// \param SkipBody If non-null, will be set to indicate if the caller should
4359	/// skip the definition of this tag and treat it as if it were a declaration.
4360	DeclResult ActOnTag(Scope S, unsigned* TagSpec, TagUseKind TUK,
4361	SourceLocation KWLoc, CXXScopeSpec &SS,
4362	IdentifierInfo *Name, SourceLocation NameLoc,
4363	const ParsedAttributesView &Attr, AccessSpecifier AS,
4364	SourceLocation ModulePrivateLoc,
4365	MultiTemplateParamsArg TemplateParameterLists,
4366	bool &OwnedDecl, bool &IsDependent,
4367	SourceLocation ScopedEnumKWLoc,
4368	bool ScopedEnumUsesClassTag, TypeResult UnderlyingType,
4369	bool IsTypeSpecifier, bool IsTemplateParamOrArg,
4370	OffsetOfKind OOK, SkipBodyInfo SkipBody = nullptr*);
4371
4372	/// ActOnField - Each field of a C struct/union is passed into this in order
4373	/// to create a FieldDecl object for it.
4374	Decl ActOnField(Scope S, Decl *TagD, SourceLocation DeclStart,
4375	Declarator &D, Expr *BitfieldWidth);
4376
4377	/// HandleField - Analyze a field of a C struct or a C++ data member.
4378	FieldDecl HandleField(Scope S, RecordDecl *TagD, SourceLocation DeclStart,
4379	Declarator &D, Expr *BitfieldWidth,
4380	InClassInitStyle InitStyle, AccessSpecifier AS);
4381
4382	/// Build a new FieldDecl and check its well-formedness.
4383	///
4384	/// This routine builds a new FieldDecl given the fields name, type,
4385	/// record, etc. \p PrevDecl should refer to any previous declaration
4386	/// with the same name and in the same scope as the field to be
4387	/// created.
4388	///
4389	/// \returns a new FieldDecl.
4390	///
4391	/// \todo The Declarator argument is a hack. It will be removed once
4392	FieldDecl *CheckFieldDecl(DeclarationName Name, QualType T,
4393	TypeSourceInfo TInfo, RecordDecl Record,
4394	SourceLocation Loc, bool Mutable,
4395	Expr *BitfieldWidth, InClassInitStyle InitStyle,
4396	SourceLocation TSSL, AccessSpecifier AS,
4397	NamedDecl PrevDecl, Declarator D = nullptr);
4398
4399	bool CheckNontrivialField(FieldDecl *FD);
4400
4401	/// ActOnLastBitfield - This routine handles synthesized bitfields rules for
4402	/// class and class extensions. For every class \@interface and class
4403	/// extension \@interface, if the last ivar is a bitfield of any type,
4404	/// then add an implicit `char :0` ivar to the end of that interface.
4405	void ActOnLastBitfield(SourceLocation DeclStart,
4406	SmallVectorImpl<Decl *> &AllIvarDecls);
4407
4408	// This is used for both record definitions and ObjC interface declarations.
4409	void ActOnFields(Scope S, SourceLocation RecLoc, Decl TagDecl,
4410	ArrayRef<Decl *> Fields, SourceLocation LBrac,
4411	SourceLocation RBrac, const ParsedAttributesView &AttrList);
4412
4413	/// ActOnTagStartDefinition - Invoked when we have entered the
4414	/// scope of a tag's definition (e.g., for an enumeration, class,
4415	/// struct, or union).
4416	void ActOnTagStartDefinition(Scope S, Decl TagDecl);
4417
4418	/// Perform ODR-like check for C/ObjC when merging tag types from modules.
4419	/// Differently from C++, actually parse the body and reject / error out
4420	/// in case of a structural mismatch.
4421	bool ActOnDuplicateDefinition(Scope S, Decl Prev, SkipBodyInfo &SkipBody);
4422
4423	typedef void *SkippedDefinitionContext;
4424
4425	/// Invoked when we enter a tag definition that we're skipping.
4426	SkippedDefinitionContext ActOnTagStartSkippedDefinition(Scope S, Decl TD);
4427
4428	/// ActOnStartCXXMemberDeclarations - Invoked when we have parsed a
4429	/// C++ record definition's base-specifiers clause and are starting its
4430	/// member declarations.
4431	void ActOnStartCXXMemberDeclarations(Scope S, Decl TagDecl,
4432	SourceLocation FinalLoc,
4433	bool IsFinalSpelledSealed,
4434	bool IsAbstract,
4435	SourceLocation LBraceLoc);
4436
4437	/// ActOnTagFinishDefinition - Invoked once we have finished parsing
4438	/// the definition of a tag (enumeration, class, struct, or union).
4439	void ActOnTagFinishDefinition(Scope S, Decl TagDecl,
4440	SourceRange BraceRange);
4441
4442	ASTContext::CXXRecordDeclRelocationInfo
4443	CheckCXX2CRelocatable(const clang::CXXRecordDecl *D);
4444
4445	void ActOnTagFinishSkippedDefinition(SkippedDefinitionContext Context);
4446
4447	/// ActOnTagDefinitionError - Invoked when there was an unrecoverable
4448	/// error parsing the definition of a tag.
4449	void ActOnTagDefinitionError(Scope S, Decl TagDecl);
4450
4451	EnumConstantDecl CheckEnumConstant(EnumDecl Enum,
4452	EnumConstantDecl *LastEnumConst,
4453	SourceLocation IdLoc, IdentifierInfo *Id,
4454	Expr *val);
4455
4456	/// Check that this is a valid underlying type for an enum declaration.
4457	bool CheckEnumUnderlyingType(TypeSourceInfo *TI);
4458
4459	/// Check whether this is a valid redeclaration of a previous enumeration.
4460	/// \return true if the redeclaration was invalid.
4461	bool CheckEnumRedeclaration(SourceLocation EnumLoc, bool IsScoped,
4462	QualType EnumUnderlyingTy, bool IsFixed,
4463	const EnumDecl *Prev);
4464
4465	/// Determine whether the body of an anonymous enumeration should be skipped.
4466	/// \param II The name of the first enumerator.
4467	SkipBodyInfo shouldSkipAnonEnumBody(Scope S, IdentifierInfo II,
4468	SourceLocation IILoc);
4469
4470	Decl ActOnEnumConstant(Scope S, Decl EnumDecl, Decl LastEnumConstant,
4471	SourceLocation IdLoc, IdentifierInfo *Id,
4472	const ParsedAttributesView &Attrs,
4473	SourceLocation EqualLoc, Expr *Val,
4474	SkipBodyInfo SkipBody = nullptr*);
4475	void ActOnEnumBody(SourceLocation EnumLoc, SourceRange BraceRange,
4476	Decl EnumDecl, ArrayRef<Decl > Elements, Scope *S,
4477	const ParsedAttributesView &Attr);
4478
4479	/// Set the current declaration context until it gets popped.
4480	void PushDeclContext(Scope S, DeclContext DC);
4481	void PopDeclContext();
4482
4483	/// EnterDeclaratorContext - Used when we must lookup names in the context
4484	/// of a declarator's nested name specifier.
4485	void EnterDeclaratorContext(Scope S, DeclContext DC);
4486	void ExitDeclaratorContext(Scope *S);
4487
4488	/// Enter a template parameter scope, after it's been associated with a
4489	/// particular DeclContext. Causes lookup within the scope to chain through
4490	/// enclosing contexts in the correct order.
4491	void EnterTemplatedContext(Scope S, DeclContext DC);
4492
4493	/// Push the parameters of D, which must be a function, into scope.
4494	void ActOnReenterFunctionContext(Scope S, Decl D);
4495	void ActOnExitFunctionContext();
4496
4497	/// Add this decl to the scope shadowed decl chains.
4498	void PushOnScopeChains(NamedDecl D, Scope S, bool AddToContext = true);
4499
4500	/// isDeclInScope - If 'Ctx' is a function/method, isDeclInScope returns true
4501	/// if 'D' is in Scope 'S', otherwise 'S' is ignored and isDeclInScope returns
4502	/// true if 'D' belongs to the given declaration context.
4503	///
4504	/// \param AllowInlineNamespace If \c true, allow the declaration to be in the
4505	/// enclosing namespace set of the context, rather than contained
4506	/// directly within it.
4507	bool isDeclInScope(NamedDecl D, DeclContext Ctx, Scope S = nullptr*,
4508	bool AllowInlineNamespace = false) const;
4509
4510	/// Finds the scope corresponding to the given decl context, if it
4511	/// happens to be an enclosing scope. Otherwise return NULL.
4512	static Scope getScopeForDeclContext(Scope S, DeclContext *DC);
4513
4514	/// Subroutines of ActOnDeclarator().
4515	TypedefDecl ParseTypedefDecl(Scope S, Declarator &D, QualType T,
4516	TypeSourceInfo *TInfo);
4517	bool isIncompatibleTypedef(const TypeDecl Old, TypedefNameDecl New);
4518
4519	/// mergeDeclAttributes - Copy attributes from the Old decl to the New one.
4520	void mergeDeclAttributes(
4521	NamedDecl New, Decl Old,
4522	AvailabilityMergeKind AMK = AvailabilityMergeKind::Redeclaration);
4523
4524	/// CheckAttributesOnDeducedType - Calls Sema functions for attributes that
4525	/// requires the type to be deduced.
4526	void CheckAttributesOnDeducedType(Decl *D);
4527
4528	/// MergeTypedefNameDecl - We just parsed a typedef 'New' which has the
4529	/// same name and scope as a previous declaration 'Old'. Figure out
4530	/// how to resolve this situation, merging decls or emitting
4531	/// diagnostics as appropriate. If there was an error, set New to be invalid.
4532	void MergeTypedefNameDecl(Scope S, TypedefNameDecl New,
4533	LookupResult &OldDecls);
4534
4535	/// CleanupMergedEnum - We have just merged the decl 'New' by making another
4536	/// definition visible.
4537	/// This method performs any necessary cleanup on the parser state to discard
4538	/// child nodes from newly parsed decl we are retiring.
4539	void CleanupMergedEnum(Scope S, Decl New);
4540
4541	/// MergeFunctionDecl - We just parsed a function 'New' from
4542	/// declarator D which has the same name and scope as a previous
4543	/// declaration 'Old'. Figure out how to resolve this situation,
4544	/// merging decls or emitting diagnostics as appropriate.
4545	///
4546	/// In C++, New and Old must be declarations that are not
4547	/// overloaded. Use IsOverload to determine whether New and Old are
4548	/// overloaded, and to select the Old declaration that New should be
4549	/// merged with.
4550	///
4551	/// Returns true if there was an error, false otherwise.
4552	bool MergeFunctionDecl(FunctionDecl New, NamedDecl &Old, Scope *S,
4553	bool MergeTypeWithOld, bool NewDeclIsDefn);
4554
4555	/// Completes the merge of two function declarations that are
4556	/// known to be compatible.
4557	///
4558	/// This routine handles the merging of attributes and other
4559	/// properties of function declarations from the old declaration to
4560	/// the new declaration, once we know that New is in fact a
4561	/// redeclaration of Old.
4562	///
4563	/// \returns false
4564	bool MergeCompatibleFunctionDecls(FunctionDecl New, FunctionDecl Old,
4565	Scope S, bool* MergeTypeWithOld);
4566	void mergeObjCMethodDecls(ObjCMethodDecl New, ObjCMethodDecl Old);
4567
4568	/// MergeVarDecl - We just parsed a variable 'New' which has the same name
4569	/// and scope as a previous declaration 'Old'. Figure out how to resolve this
4570	/// situation, merging decls or emitting diagnostics as appropriate.
4571	///
4572	/// Tentative definition rules (C99 6.9.2p2) are checked by
4573	/// FinalizeDeclaratorGroup. Unfortunately, we can't analyze tentative
4574	/// definitions here, since the initializer hasn't been attached.
4575	void MergeVarDecl(VarDecl *New, LookupResult &Previous);
4576
4577	/// MergeVarDeclTypes - We parsed a variable 'New' which has the same name and
4578	/// scope as a previous declaration 'Old'. Figure out how to merge their
4579	/// types, emitting diagnostics as appropriate.
4580	///
4581	/// Declarations using the auto type specifier (C++ [decl.spec.auto]) call
4582	/// back to here in AddInitializerToDecl. We can't check them before the
4583	/// initializer is attached.
4584	void MergeVarDeclTypes(VarDecl New, VarDecl Old, bool MergeTypeWithOld);
4585
4586	/// We've just determined that \p Old and \p New both appear to be definitions
4587	/// of the same variable. Either diagnose or fix the problem.
4588	bool checkVarDeclRedefinition(VarDecl OldDefn, VarDecl NewDefn);
4589	void notePreviousDefinition(const NamedDecl *Old, SourceLocation New);
4590
4591	/// Filters out lookup results that don't fall within the given scope
4592	/// as determined by isDeclInScope.
4593	void FilterLookupForScope(LookupResult &R, DeclContext Ctx, Scope S,
4594	bool ConsiderLinkage, bool AllowInlineNamespace);
4595
4596	/// We've determined that \p New is a redeclaration of \p Old. Check that they
4597	/// have compatible owning modules.
4598	bool CheckRedeclarationModuleOwnership(NamedDecl New, NamedDecl Old);
4599
4600	/// [module.interface]p6:
4601	/// A redeclaration of an entity X is implicitly exported if X was introduced
4602	/// by an exported declaration; otherwise it shall not be exported.
4603	bool CheckRedeclarationExported(NamedDecl New, NamedDecl Old);
4604
4605	/// A wrapper function for checking the semantic restrictions of
4606	/// a redeclaration within a module.
4607	bool CheckRedeclarationInModule(NamedDecl New, NamedDecl Old);
4608
4609	/// Check the redefinition in C++20 Modules.
4610	///
4611	/// [basic.def.odr]p14:
4612	/// For any definable item D with definitions in multiple translation units,
4613	/// - if D is a non-inline non-templated function or variable, or
4614	/// - if the definitions in different translation units do not satisfy the
4615	/// following requirements,
4616	/// the program is ill-formed; a diagnostic is required only if the
4617	/// definable item is attached to a named module and a prior definition is
4618	/// reachable at the point where a later definition occurs.
4619	/// - Each such definition shall not be attached to a named module
4620	/// ([module.unit]).
4621	/// - Each such definition shall consist of the same sequence of tokens, ...
4622	/// ...
4623	///
4624	/// Return true if the redefinition is not allowed. Return false otherwise.
4625	bool IsRedefinitionInModule(const NamedDecl New, const* NamedDecl Old) const*;
4626
4627	bool ShouldWarnIfUnusedFileScopedDecl(const DeclaratorDecl D) const*;
4628
4629	/// If it's a file scoped decl that must warn if not used, keep track
4630	/// of it.
4631	void MarkUnusedFileScopedDecl(const DeclaratorDecl *D);
4632
4633	typedef llvm::function_ref<void(SourceLocation Loc, PartialDiagnostic PD)>
4634	DiagReceiverTy;
4635
4636	void DiagnoseUnusedNestedTypedefs(const RecordDecl *D);
4637	void DiagnoseUnusedNestedTypedefs(const RecordDecl *D,
4638	DiagReceiverTy DiagReceiver);
4639	void DiagnoseUnusedDecl(const NamedDecl *ND);
4640
4641	/// DiagnoseUnusedDecl - Emit warnings about declarations that are not used
4642	/// unless they are marked attr(unused).
4643	void DiagnoseUnusedDecl(const NamedDecl *ND, DiagReceiverTy DiagReceiver);
4644
4645	/// If VD is set but not otherwise used, diagnose, for a parameter or a
4646	/// variable.
4647	void DiagnoseUnusedButSetDecl(const VarDecl *VD, DiagReceiverTy DiagReceiver);
4648
4649	/// getNonFieldDeclScope - Retrieves the innermost scope, starting
4650	/// from S, where a non-field would be declared. This routine copes
4651	/// with the difference between C and C++ scoping rules in structs and
4652	/// unions. For example, the following code is well-formed in C but
4653	/// ill-formed in C++:
4654	/// @code
4655	/// struct S6 {
4656	/// enum { BAR } e;
4657	/// };
4658	///
4659	/// void test_S6() {
4660	/// struct S6 a;
4661	/// a.e = BAR;
4662	/// }
4663	/// @endcode
4664	/// For the declaration of BAR, this routine will return a different
4665	/// scope. The scope S will be the scope of the unnamed enumeration
4666	/// within S6. In C++, this routine will return the scope associated
4667	/// with S6, because the enumeration's scope is a transparent
4668	/// context but structures can contain non-field names. In C, this
4669	/// routine will return the translation unit scope, since the
4670	/// enumeration's scope is a transparent context and structures cannot
4671	/// contain non-field names.
4672	Scope getNonFieldDeclScope(Scope S);
4673
4674	FunctionDecl CreateBuiltin(IdentifierInfo II, QualType Type, unsigned ID,
4675	SourceLocation Loc);
4676
4677	/// LazilyCreateBuiltin - The specified Builtin-ID was first used at
4678	/// file scope. lazily create a decl for it. ForRedeclaration is true
4679	/// if we're creating this built-in in anticipation of redeclaring the
4680	/// built-in.
4681	NamedDecl LazilyCreateBuiltin(IdentifierInfo II, unsigned ID, Scope *S,
4682	bool ForRedeclaration, SourceLocation Loc);
4683
4684	/// Get the outermost AttributedType node that sets a calling convention.
4685	/// Valid types should not have multiple attributes with different CCs.
4686	const AttributedType getCallingConvAttributedType(QualType T) const*;
4687
4688	/// GetNameForDeclarator - Determine the full declaration name for the
4689	/// given Declarator.
4690	DeclarationNameInfo GetNameForDeclarator(Declarator &D);
4691
4692	/// Retrieves the declaration name from a parsed unqualified-id.
4693	DeclarationNameInfo GetNameFromUnqualifiedId(const UnqualifiedId &Name);
4694
4695	/// ParsingInitForAutoVars - a set of declarations with auto types for which
4696	/// we are currently parsing the initializer.
4697	llvm::SmallPtrSet<const Decl *, `4`> ParsingInitForAutoVars;
4698
4699	/// Look for a locally scoped extern "C" declaration by the given name.
4700	NamedDecl *findLocallyScopedExternCDecl(DeclarationName Name);
4701
4702	void deduceOpenCLAddressSpace(VarDecl *decl);
4703	void deduceHLSLAddressSpace(VarDecl *decl);
4704
4705	/// Adjust the \c DeclContext for a function or variable that might be a
4706	/// function-local external declaration.
4707	static bool adjustContextForLocalExternDecl(DeclContext *&DC);
4708
4709	void MarkTypoCorrectedFunctionDefinition(const NamedDecl *F);
4710
4711	/// Checks if the variant/multiversion functions are compatible.
4712	bool areMultiversionVariantFunctionsCompatible(
4713	const FunctionDecl OldFD, const* FunctionDecl *NewFD,
4714	const PartialDiagnostic &NoProtoDiagID,
4715	const PartialDiagnosticAt &NoteCausedDiagIDAt,
4716	const PartialDiagnosticAt &NoSupportDiagIDAt,
4717	const PartialDiagnosticAt &DiffDiagIDAt, bool TemplatesSupported,
4718	bool ConstexprSupported, bool CLinkageMayDiffer);
4719
4720	/// type checking declaration initializers (C99 6.7.8)
4721	bool CheckForConstantInitializer(
4722	Expr Init, unsigned* DiagID = diag::err_init_element_not_constant);
4723
4724	QualType deduceVarTypeFromInitializer(VarDecl *VDecl, DeclarationName Name,
4725	QualType Type, TypeSourceInfo *TSI,
4726	SourceRange Range, bool DirectInit,
4727	Expr *Init);
4728
4729	bool DeduceVariableDeclarationType(VarDecl VDecl, bool* DirectInit,
4730	Expr *Init);
4731
4732	sema::LambdaScopeInfo RebuildLambdaScopeInfo(CXXMethodDecl CallOperator);
4733
4734	// Heuristically tells if the function is `get_return_object` member of a
4735	// coroutine promise_type by matching the function name.
4736	static bool CanBeGetReturnObject(const FunctionDecl *FD);
4737	static bool CanBeGetReturnTypeOnAllocFailure(const FunctionDecl *FD);
4738
4739	/// ImplicitlyDefineFunction - An undeclared identifier was used in a function
4740	/// call, forming a call to an implicitly defined function (per C99 6.5.1p2).
4741	NamedDecl *ImplicitlyDefineFunction(SourceLocation Loc, IdentifierInfo &II,
4742	Scope *S);
4743
4744	/// If this function is a C++ replaceable global allocation function
4745	/// (C++2a [basic.stc.dynamic.allocation], C++2a [new.delete]),
4746	/// adds any function attributes that we know a priori based on the standard.
4747	///
4748	/// We need to check for duplicate attributes both here and where user-written
4749	/// attributes are applied to declarations.
4750	void AddKnownFunctionAttributesForReplaceableGlobalAllocationFunction(
4751	FunctionDecl *FD);
4752
4753	/// Adds any function attributes that we know a priori based on
4754	/// the declaration of this function.
4755	///
4756	/// These attributes can apply both to implicitly-declared builtins
4757	/// (like __builtin___printf_chk) or to library-declared functions
4758	/// like NSLog or printf.
4759	///
4760	/// We need to check for duplicate attributes both here and where user-written
4761	/// attributes are applied to declarations.
4762	void AddKnownFunctionAttributes(FunctionDecl *FD);
4763
4764	/// VerifyBitField - verifies that a bit field expression is an ICE and has
4765	/// the correct width, and that the field type is valid.
4766	/// Returns false on success.
4767	ExprResult VerifyBitField(SourceLocation FieldLoc,
4768	const IdentifierInfo *FieldName, QualType FieldTy,
4769	bool IsMsStruct, Expr *BitWidth);
4770
4771	/// IsValueInFlagEnum - Determine if a value is allowed as part of a flag
4772	/// enum. If AllowMask is true, then we also allow the complement of a valid
4773	/// value, to be used as a mask.
4774	bool IsValueInFlagEnum(const EnumDecl ED, const* llvm::APInt &Val,
4775	bool AllowMask) const;
4776
4777	/// ActOnPragmaWeakID - Called on well formed \#pragma weak ident.
4778	void ActOnPragmaWeakID(IdentifierInfo *WeakName, SourceLocation PragmaLoc,
4779	SourceLocation WeakNameLoc);
4780
4781	/// ActOnPragmaRedefineExtname - Called on well formed
4782	/// \#pragma redefine_extname oldname newname.
4783	void ActOnPragmaRedefineExtname(IdentifierInfo *WeakName,
4784	IdentifierInfo *AliasName,
4785	SourceLocation PragmaLoc,
4786	SourceLocation WeakNameLoc,
4787	SourceLocation AliasNameLoc);
4788
4789	/// ActOnPragmaWeakAlias - Called on well formed \#pragma weak ident = ident.
4790	void ActOnPragmaWeakAlias(IdentifierInfo WeakName, IdentifierInfo AliasName,
4791	SourceLocation PragmaLoc,
4792	SourceLocation WeakNameLoc,
4793	SourceLocation AliasNameLoc);
4794
4795	/// Status of the function emission on the CUDA/HIP/OpenMP host/device attrs.
4796	enum class FunctionEmissionStatus {
4797	Emitted,
4798	CUDADiscarded, // Discarded due to CUDA/HIP hostness
4799	OMPDiscarded, // Discarded due to OpenMP hostness
4800	TemplateDiscarded, // Discarded due to uninstantiated templates
4801	Unknown,
4802	};
4803	FunctionEmissionStatus getEmissionStatus(const FunctionDecl *Decl,
4804	bool Final = false);
4805
4806	// Whether the callee should be ignored in CUDA/HIP/OpenMP host/device check.
4807	bool shouldIgnoreInHostDeviceCheck(FunctionDecl *Callee);
4808
4809	/// Function or variable declarations to be checked for whether the deferred
4810	/// diagnostics should be emitted.
4811	llvm::SmallSetVector<Decl *, `4`> DeclsToCheckForDeferredDiags;
4812
4813	private:
4814	/// Map of current shadowing declarations to shadowed declarations. Warn if
4815	/// it looks like the user is trying to modify the shadowing declaration.
4816	llvm::DenseMap<const NamedDecl , const* NamedDecl *> ShadowingDecls;
4817
4818	// We need this to handle
4819	//
4820	// typedef struct {
4821	// void foo() { return 0; }*
4822	// } A;
4823	//
4824	// When we see foo we don't know if after the typedef we will get 'A' or 'A'*
4825	// for example. If 'A', foo will have external linkage. If we have 'A',*
4826	// foo will have no linkage. Since we can't know until we get to the end
4827	// of the typedef, this function finds out if D might have non-external
4828	// linkage. Callers should verify at the end of the TU if it D has external
4829	// linkage or not.
4830	static bool mightHaveNonExternalLinkage(const DeclaratorDecl *FD);
4831
4832	#include "clang/Sema/AttrIsTypeDependent.inc"
4833
4834	///@}
4835
4836	//
4837	//
4838	// -------------------------------------------------------------------------
4839	//
4840	//
4841
4842	/// \name Declaration Attribute Handling
4843	/// Implementations are in SemaDeclAttr.cpp
4844	///@{
4845
4846	public:
4847	/// Describes the kind of priority given to an availability attribute.
4848	///
4849	/// The sum of priorities deteremines the final priority of the attribute.
4850	/// The final priority determines how the attribute will be merged.
4851	/// An attribute with a lower priority will always remove higher priority
4852	/// attributes for the specified platform when it is being applied. An
4853	/// attribute with a higher priority will not be applied if the declaration
4854	/// already has an availability attribute with a lower priority for the
4855	/// specified platform. The final prirority values are not expected to match
4856	/// the values in this enumeration, but instead should be treated as a plain
4857	/// integer value. This enumeration just names the priority weights that are
4858	/// used to calculate that final vaue.
4859	enum AvailabilityPriority : int {
4860	/// The availability attribute was specified explicitly next to the
4861	/// declaration.
4862	AP_Explicit = `0`,
4863
4864	/// The availability attribute was applied using '#pragma clang attribute'.
4865	AP_PragmaClangAttribute = `1`,
4866
4867	/// The availability attribute for a specific platform was inferred from
4868	/// an availability attribute for another platform.
4869	AP_InferredFromOtherPlatform = `2`,
4870
4871	/// The availability attribute was inferred from an 'anyAppleOS'
4872	/// availability attribute.
4873	AP_InferredFromAnyAppleOS = `3`,
4874
4875	/// The availability attribute was inferred from an 'anyAppleOS'
4876	/// availability attribute that was applied using '#pragma clang attribute'.
4877	/// This has the lowest priority.
4878	AP_PragmaClangAttribute_InferredFromAnyAppleOS = `4`
4879	};
4880
4881	/// Describes the reason a calling convention specification was ignored, used
4882	/// for diagnostics.
4883	enum class CallingConventionIgnoredReason {
4884	ForThisTarget = `0`,
4885	VariadicFunction,
4886	ConstructorDestructor,
4887	BuiltinFunction
4888	};
4889
4890	/// A helper function to provide Attribute Location for the Attr types
4891	/// AND the ParsedAttr.
4892	template <typename AttrInfo>
4893	static std::enable_if_t<std::is_base_of_v<Attr, AttrInfo>, SourceLocation>
4894	getAttrLoc(const AttrInfo &AL) {
4895	return AL.getLocation();
4896	}
4897	SourceLocation getAttrLoc(const AttributeCommonInfo &CI);
4898
4899	/// If Expr is a valid integer constant, get the value of the integer
4900	/// expression and return success or failure. May output an error.
4901	///
4902	/// Negative argument is implicitly converted to unsigned, unless
4903	/// \p StrictlyUnsigned is true.
4904	template <typename AttrInfo>
4905	bool checkUInt32Argument(const AttrInfo &AI, const Expr *Expr, uint32_t &Val,
4906	unsigned Idx = UINT_MAX,
4907	bool StrictlyUnsigned = false) {
4908	std::optional<llvm::APSInt> I = llvm::APSInt (`32`);
4909	if (Expr->isTypeDependent() \|\|
4910	!(I = Expr->getIntegerConstantExpr(Ctx: Context))) {
4911	if (Idx != UINT_MAX)
4912	Diag(getAttrLoc(AI), diag::err_attribute_argument_n_type)
4913	<< &AI << Idx << AANT_ArgumentIntegerConstant
4914	<< Expr->getSourceRange();
4915	else
4916	Diag(getAttrLoc(AI), diag::err_attribute_argument_type)
4917	<< &AI << AANT_ArgumentIntegerConstant << Expr->getSourceRange();
4918	return false;
4919	}
4920
4921	if (!I ->isIntN(N: `32`)) {
4922	Diag(Loc: Expr->getExprLoc(), DiagID: diag::err_ice_too_large)
4923	<< toString(I: I, Radix: `10`, Signed: false) << `32` << /* Unsigned / `1`;
4924	return false;
4925	}
4926
4927	if (StrictlyUnsigned && I ->isSigned() && I ->isNegative()) {
4928	Diag(getAttrLoc(AI), diag::err_attribute_requires_positive_integer)
4929	<< &AI << /non-negative/ `1`;
4930	return false;
4931	}
4932
4933	Val = (uint32_t)I ->getZExtValue();
4934	return true;
4935	}
4936
4937	/// WeakTopLevelDecl - Translation-unit scoped declarations generated by
4938	/// \#pragma weak during processing of other Decls.
4939	/// I couldn't figure out a clean way to generate these in-line, so
4940	/// we store them here and handle separately -- which is a hack.
4941	/// It would be best to refactor this.
4942	SmallVector<Decl *, `2`> WeakTopLevelDecl;
4943
4944	/// WeakTopLevelDeclDecls - access to \#pragma weak-generated Decls
4945	SmallVectorImpl<Decl > &WeakTopLevelDecls() { return* WeakTopLevelDecl; }
4946
4947	typedef LazyVector<TypedefNameDecl *, ExternalSemaSource,
4948	&ExternalSemaSource::ReadExtVectorDecls, `2`, `2`>
4949	ExtVectorDeclsType;
4950
4951	/// ExtVectorDecls - This is a list all the extended vector types. This allows
4952	/// us to associate a raw vector type with one of the ext_vector type names.
4953	/// This is only necessary for issuing pretty diagnostics.
4954	ExtVectorDeclsType ExtVectorDecls;
4955
4956	/// Check if the argument \p E is a ASCII string literal. If not emit an error
4957	/// and return false, otherwise set \p Str to the value of the string literal
4958	/// and return true.
4959	bool checkStringLiteralArgumentAttr(const AttributeCommonInfo &CI,
4960	const Expr *E, StringRef &Str,
4961	SourceLocation ArgLocation = nullptr*);
4962
4963	/// Check if the argument \p ArgNum of \p Attr is a ASCII string literal.
4964	/// If not emit an error and return false. If the argument is an identifier it
4965	/// will emit an error with a fixit hint and treat it as if it was a string
4966	/// literal.
4967	bool checkStringLiteralArgumentAttr(const ParsedAttr &Attr, unsigned ArgNum,
4968	StringRef &Str,
4969	SourceLocation ArgLocation = nullptr*);
4970
4971	/// Determine if type T is a valid subject for a nonnull and similar
4972	/// attributes. Dependent types are considered valid so they can be checked
4973	/// during instantiation time. By default, we look through references (the
4974	/// behavior used by nonnull), but if the second parameter is true, then we
4975	/// treat a reference type as valid.
4976	bool isValidPointerAttrType(QualType T, bool RefOkay = false);
4977
4978	/// AddAssumeAlignedAttr - Adds an assume_aligned attribute to a particular
4979	/// declaration.
4980	void AddAssumeAlignedAttr(Decl D, const* AttributeCommonInfo &CI, Expr *E,
4981	Expr *OE);
4982
4983	/// AddAllocAlignAttr - Adds an alloc_align attribute to a particular
4984	/// declaration.
4985	void AddAllocAlignAttr(Decl D, const* AttributeCommonInfo &CI,
4986	Expr *ParamExpr);
4987
4988	bool CheckAttrTarget(const ParsedAttr &CurrAttr);
4989	bool CheckAttrNoArgs(const ParsedAttr &CurrAttr);
4990
4991	AvailabilityAttr *
4992	mergeAvailabilityAttr(NamedDecl D, const* AttributeCommonInfo &CI,
4993	const IdentifierInfo Platform, bool* Implicit,
4994	VersionTuple Introduced, VersionTuple Deprecated,
4995	VersionTuple Obsoleted, bool IsUnavailable,
4996	StringRef Message, bool IsStrict, StringRef Replacement,
4997	AvailabilityMergeKind AMK, int Priority,
4998	const IdentifierInfo *IIEnvironment,
4999	VersionTuple OrigAnyAppleOSVersion = {});
5000
5001	TypeVisibilityAttr *
5002	mergeTypeVisibilityAttr(Decl D, const* AttributeCommonInfo &CI,
5003	TypeVisibilityAttr::VisibilityType Vis);
5004	VisibilityAttr mergeVisibilityAttr(Decl D, const AttributeCommonInfo &CI,
5005	VisibilityAttr::VisibilityType Vis);
5006	void mergeVisibilityType(Decl *D, SourceLocation Loc,
5007	VisibilityAttr::VisibilityType Type);
5008	SectionAttr mergeSectionAttr(Decl D, const AttributeCommonInfo &CI,
5009	StringRef Name);
5010
5011	/// Used to implement to perform semantic checking on
5012	/// attribute((section("foo"))) specifiers.
5013	///
5014	/// In this case, "foo" is passed in to be checked. If the section
5015	/// specifier is invalid, return an Error that indicates the problem.
5016	///
5017	/// This is a simple quality of implementation feature to catch errors
5018	/// and give good diagnostics in cases when the assembler or code generator
5019	/// would otherwise reject the section specifier.
5020	llvm::Error isValidSectionSpecifier(StringRef Str);
5021	bool checkSectionName(SourceLocation LiteralLoc, StringRef Str);
5022	CodeSegAttr mergeCodeSegAttr(Decl D, const AttributeCommonInfo &CI,
5023	StringRef Name);
5024
5025	// Check for things we'd like to warn about. Multiversioning issues are
5026	// handled later in the process, once we know how many exist.
5027	bool checkTargetAttr(SourceLocation LiteralLoc, StringRef Str);
5028
5029	ErrorAttr mergeErrorAttr(Decl D, const AttributeCommonInfo &CI,
5030	StringRef NewUserDiagnostic);
5031	FormatAttr mergeFormatAttr(Decl D, const AttributeCommonInfo &CI,
5032	const IdentifierInfo Format, int* FormatIdx,
5033	int FirstArg);
5034	FormatMatchesAttr mergeFormatMatchesAttr(Decl D,
5035	const AttributeCommonInfo &CI,
5036	const IdentifierInfo *Format,
5037	int FormatIdx,
5038	StringLiteral *FormatStr);
5039	ModularFormatAttr mergeModularFormatAttr(Decl D,
5040	const AttributeCommonInfo &CI,
5041	const IdentifierInfo *ModularImplFn,
5042	StringRef ImplName,
5043	MutableArrayRef<StringRef> Aspects);
5044
5045	PersonalityAttr mergePersonalityAttr(Decl D, FunctionDecl *Routine,
5046	const AttributeCommonInfo &CI);
5047
5048	/// AddAlignedAttr - Adds an aligned attribute to a particular declaration.
5049	void AddAlignedAttr(Decl D, const* AttributeCommonInfo &CI, Expr *E,
5050	bool IsPackExpansion);
5051	void AddAlignedAttr(Decl D, const* AttributeCommonInfo &CI, TypeSourceInfo *T,
5052	bool IsPackExpansion);
5053
5054	/// AddAlignValueAttr - Adds an align_value attribute to a particular
5055	/// declaration.
5056	void AddAlignValueAttr(Decl D, const* AttributeCommonInfo &CI, Expr *E);
5057
5058	/// CreateAnnotationAttr - Creates an annotation Annot with Args arguments.
5059	Attr CreateAnnotationAttr(const* AttributeCommonInfo &CI, StringRef Annot,
5060	MutableArrayRef<Expr *> Args);
5061	Attr CreateAnnotationAttr(const* ParsedAttr &AL);
5062
5063	bool checkMSInheritanceAttrOnDefinition(CXXRecordDecl *RD, SourceRange Range,
5064	bool BestCase,
5065	MSInheritanceModel SemanticSpelling);
5066
5067	void CheckAlignasUnderalignment(Decl *D);
5068
5069	/// AddModeAttr - Adds a mode attribute to a particular declaration.
5070	void AddModeAttr(Decl D, const* AttributeCommonInfo &CI,
5071	const IdentifierInfo Name, bool* InInstantiation = false);
5072	AlwaysInlineAttr mergeAlwaysInlineAttr(Decl D,
5073	const AttributeCommonInfo &CI,
5074	const IdentifierInfo *Ident);
5075	MinSizeAttr mergeMinSizeAttr(Decl D, const AttributeCommonInfo &CI);
5076	OptimizeNoneAttr mergeOptimizeNoneAttr(Decl D,
5077	const AttributeCommonInfo &CI);
5078	InternalLinkageAttr mergeInternalLinkageAttr(Decl D, const ParsedAttr &AL);
5079	InternalLinkageAttr mergeInternalLinkageAttr(Decl D,
5080	const InternalLinkageAttr &AL);
5081
5082	/// Check validaty of calling convention attribute \p attr. If \p FD
5083	/// is not null pointer, use \p FD to determine the CUDA/HIP host/device
5084	/// target. Otherwise, it is specified by \p CFT.
5085	bool CheckCallingConvAttr(
5086	const ParsedAttr &attr, CallingConv &CC, const FunctionDecl FD = nullptr*,
5087	CUDAFunctionTarget CFT = CUDAFunctionTarget::InvalidTarget);
5088
5089	/// Checks a regparm attribute, returning true if it is ill-formed and
5090	/// otherwise setting numParams to the appropriate value.
5091	bool CheckRegparmAttr(const ParsedAttr &attr, unsigned &value);
5092
5093	/// Create an CUDALaunchBoundsAttr attribute.
5094	CUDALaunchBoundsAttr CreateLaunchBoundsAttr(const* AttributeCommonInfo &CI,
5095	Expr *MaxThreads,
5096	Expr *MinBlocks,
5097	Expr *MaxBlocks);
5098
5099	/// AddLaunchBoundsAttr - Adds a launch_bounds attribute to a particular
5100	/// declaration.
5101	void AddLaunchBoundsAttr(Decl D, const* AttributeCommonInfo &CI,
5102	Expr MaxThreads, Expr MinBlocks, Expr *MaxBlocks);
5103
5104	/// Add a cluster_dims attribute to a particular declaration.
5105	CUDAClusterDimsAttr createClusterDimsAttr(const* AttributeCommonInfo &CI,
5106	Expr X, Expr Y, Expr *Z);
5107	void addClusterDimsAttr(Decl D, const* AttributeCommonInfo &CI, Expr *X,
5108	Expr Y, Expr Z);
5109	/// Add a no_cluster attribute to a particular declaration.
5110	void addNoClusterAttr(Decl D, const* AttributeCommonInfo &CI);
5111
5112	enum class RetainOwnershipKind { NS, CF, OS };
5113
5114	UuidAttr mergeUuidAttr(Decl D, const AttributeCommonInfo &CI,
5115	StringRef UuidAsWritten, MSGuidDecl *GuidDecl);
5116
5117	BTFDeclTagAttr mergeBTFDeclTagAttr(Decl D, const BTFDeclTagAttr &AL);
5118
5119	DLLImportAttr mergeDLLImportAttr(Decl D, const AttributeCommonInfo &CI);
5120	DLLExportAttr mergeDLLExportAttr(Decl D, const AttributeCommonInfo &CI);
5121	MSInheritanceAttr mergeMSInheritanceAttr(Decl D,
5122	const AttributeCommonInfo &CI,
5123	bool BestCase,
5124	MSInheritanceModel Model);
5125
5126	EnforceTCBAttr mergeEnforceTCBAttr(Decl D, const EnforceTCBAttr &AL);
5127	EnforceTCBLeafAttr mergeEnforceTCBLeafAttr(Decl D,
5128	const EnforceTCBLeafAttr &AL);
5129
5130	/// Helper for delayed processing TransparentUnion or
5131	/// BPFPreserveAccessIndexAttr attribute.
5132	void ProcessDeclAttributeDelayed(Decl *D,
5133	const ParsedAttributesView &AttrList);
5134
5135	// Options for ProcessDeclAttributeList().
5136	struct ProcessDeclAttributeOptions {
5137	ProcessDeclAttributeOptions()
5138	: IncludeCXX11Attributes(true), IgnoreTypeAttributes(false) {}
5139
5140	ProcessDeclAttributeOptions WithIncludeCXX11Attributes(bool Val) {
5141	ProcessDeclAttributeOptions Result = *this;
5142	Result.IncludeCXX11Attributes = Val;
5143	return Result;
5144	}
5145
5146	ProcessDeclAttributeOptions WithIgnoreTypeAttributes(bool Val) {
5147	ProcessDeclAttributeOptions Result = *this;
5148	Result.IgnoreTypeAttributes = Val;
5149	return Result;
5150	}
5151
5152	// Should C++11 attributes be processed?
5153	bool IncludeCXX11Attributes;
5154
5155	// Should any type attributes encountered be ignored?
5156	// If this option is false, a diagnostic will be emitted for any type
5157	// attributes of a kind that does not "slide" from the declaration to
5158	// the decl-specifier-seq.
5159	bool IgnoreTypeAttributes;
5160	};
5161
5162	/// ProcessDeclAttributeList - Apply all the decl attributes in the specified
5163	/// attribute list to the specified decl, ignoring any type attributes.
5164	void ProcessDeclAttributeList(Scope S, Decl D,
5165	const ParsedAttributesView &AttrList,
5166	const ProcessDeclAttributeOptions &Options =
5167	ProcessDeclAttributeOptions ());
5168
5169	/// Annotation attributes are the only attributes allowed after an access
5170	/// specifier.
5171	bool ProcessAccessDeclAttributeList(AccessSpecDecl *ASDecl,
5172	const ParsedAttributesView &AttrList);
5173
5174	/// checkUnusedDeclAttributes - Given a declarator which is not being
5175	/// used to build a declaration, complain about any decl attributes
5176	/// which might be lying around on it.
5177	void checkUnusedDeclAttributes(Declarator &D);
5178
5179	void DiagnoseUnknownAttribute(const ParsedAttr &AL);
5180
5181	/// DeclClonePragmaWeak - clone existing decl (maybe definition),
5182	/// \#pragma weak needs a non-definition decl and source may not have one.
5183	NamedDecl DeclClonePragmaWeak(NamedDecl ND, const IdentifierInfo *II,
5184	SourceLocation Loc);
5185
5186	/// DeclApplyPragmaWeak - A declaration (maybe definition) needs \#pragma weak
5187	/// applied to it, possibly with an alias.
5188	void DeclApplyPragmaWeak(Scope S, NamedDecl ND, const WeakInfo &W);
5189
5190	void ProcessPragmaWeak(Scope S, Decl D);
5191	// Decl attributes - this routine is the top level dispatcher.
5192	void ProcessDeclAttributes(Scope S, Decl D, const Declarator &PD);
5193
5194	void PopParsingDeclaration(ParsingDeclState state, Decl *decl);
5195
5196	/// Given a set of delayed diagnostics, re-emit them as if they had
5197	/// been delayed in the current context instead of in the given pool.
5198	/// Essentially, this just moves them to the current pool.
5199	void redelayDiagnostics(sema::DelayedDiagnosticPool &pool);
5200
5201	/// Check that the type is a plain record with one field being a pointer
5202	/// type and the other field being an integer. This matches the common
5203	/// implementation of std::span or sized_allocation_t in P0901R11.
5204	bool CheckSpanLikeType(const AttributeCommonInfo &CI, const QualType &Ty);
5205
5206	/// Check if IdxExpr is a valid parameter index for a function or
5207	/// instance method D. May output an error.
5208	///
5209	/// \returns true if IdxExpr is a valid index.
5210	template <typename AttrInfo>
5211	bool checkFunctionOrMethodParameterIndex(
5212	const Decl D, const* AttrInfo &AI, unsigned AttrArgNum,
5213	const Expr IdxExpr, ParamIdx &Idx, bool* CanIndexImplicitThis = false,
5214	bool CanIndexVariadicArguments = false) {
5215	assert(isFunctionOrMethodOrBlockForAttrSubject(D));
5216
5217	// In C++ the implicit 'this' function parameter also counts.
5218	// Parameters are counted from one.
5219	bool HP = hasFunctionProto(D);
5220	bool HasImplicitThisParam = hasImplicitObjectParameter(D);
5221	bool IV = HP && isFunctionOrMethodVariadic(D);
5222	unsigned NumParams =
5223	(HP ? getFunctionOrMethodNumParams(D) : `0`) + HasImplicitThisParam;
5224
5225	std::optional<llvm::APSInt> IdxInt;
5226	if (IdxExpr->isTypeDependent() \|\|
5227	!(IdxInt = IdxExpr->getIntegerConstantExpr(Ctx: Context))) {
5228	Diag(getAttrLoc(AI), diag::err_attribute_argument_n_type)
5229	<< &AI << AttrArgNum << AANT_ArgumentIntegerConstant
5230	<< IdxExpr->getSourceRange();
5231	return false;
5232	}
5233
5234	constexpr unsigned Limit = `1` << ParamIdx::IdxBitWidth;
5235	unsigned IdxSource = IdxInt ->getLimitedValue(Limit);
5236	if (IdxSource < `1` \|\| IdxSource == Limit \|\|
5237	((!IV \|\| !CanIndexVariadicArguments) && IdxSource > NumParams)) {
5238	Diag(getAttrLoc(AI), diag::err_attribute_argument_out_of_bounds)
5239	<< &AI << AttrArgNum << IdxExpr->getSourceRange();
5240	return false;
5241	}
5242	if (HasImplicitThisParam && !CanIndexImplicitThis) {
5243	if (IdxSource == `1`) {
5244	Diag(getAttrLoc(AI), diag::err_attribute_invalid_implicit_this_argument)
5245	<< &AI << IdxExpr->getSourceRange();
5246	return false;
5247	}
5248	}
5249
5250	Idx = ParamIdx (IdxSource, D);
5251	return true;
5252	}
5253
5254	///@}
5255
5256	//
5257	//
5258	// -------------------------------------------------------------------------
5259	//
5260	//
5261
5262	/// \name C++ Declarations
5263	/// Implementations are in SemaDeclCXX.cpp
5264	///@{
5265
5266	public:
5267	void CheckDelegatingCtorCycles();
5268
5269	/// Called before parsing a function declarator belonging to a function
5270	/// declaration.
5271	void ActOnStartFunctionDeclarationDeclarator(Declarator &D,
5272	unsigned TemplateParameterDepth);
5273
5274	/// Called after parsing a function declarator belonging to a function
5275	/// declaration.
5276	void ActOnFinishFunctionDeclarationDeclarator(Declarator &D);
5277
5278	// Act on C++ namespaces
5279	Decl ActOnStartNamespaceDef(Scope S, SourceLocation InlineLoc,
5280	SourceLocation NamespaceLoc,
5281	SourceLocation IdentLoc, IdentifierInfo *Ident,
5282	SourceLocation LBrace,
5283	const ParsedAttributesView &AttrList,
5284	UsingDirectiveDecl &UsingDecl, bool* IsNested);
5285
5286	/// ActOnFinishNamespaceDef - This callback is called after a namespace is
5287	/// exited. Decl is the DeclTy returned by ActOnStartNamespaceDef.
5288	void ActOnFinishNamespaceDef(Decl *Dcl, SourceLocation RBrace);
5289
5290	NamespaceDecl getStdNamespace() const*;
5291
5292	/// Retrieve the special "std" namespace, which may require us to
5293	/// implicitly define the namespace.
5294	NamespaceDecl *getOrCreateStdNamespace();
5295
5296	CXXRecordDecl getStdBadAlloc() const*;
5297	EnumDecl getStdAlignValT() const*;
5298
5299	TypeAwareAllocationMode ShouldUseTypeAwareOperatorNewOrDelete() const;
5300	FunctionDecl BuildTypeAwareUsualDelete(FunctionTemplateDecl FnDecl,
5301	QualType AllocType, SourceLocation);
5302
5303	ValueDecl tryLookupUnambiguousFieldDecl(RecordDecl ClassDecl,
5304	const IdentifierInfo *MemberOrBase);
5305
5306	enum class ComparisonCategoryUsage {
5307	/// The '<=>' operator was used in an expression and a builtin operator
5308	/// was selected.
5309	OperatorInExpression,
5310	/// A defaulted 'operator<=>' needed the comparison category. This
5311	/// typically only applies to 'std::strong_ordering', due to the implicit
5312	/// fallback return value.
5313	DefaultedOperator,
5314	};
5315
5316	/// Lookup the specified comparison category types in the standard
5317	/// library, an check the VarDecls possibly returned by the operator<=>
5318	/// builtins for that type.
5319	///
5320	/// \return The type of the comparison category type corresponding to the
5321	/// specified Kind, or a null type if an error occurs
5322	QualType CheckComparisonCategoryType(ComparisonCategoryType Kind,
5323	SourceLocation Loc,
5324	ComparisonCategoryUsage Usage);
5325
5326	/// Tests whether Ty is an instance of std::initializer_list and, if
5327	/// it is and Element is not NULL, assigns the element type to Element.
5328	bool isStdInitializerList(QualType Ty, QualType *Element);
5329
5330	/// Tests whether Ty is an instance of std::type_identity and, if
5331	/// it is and TypeArgument is not NULL, assigns the element type to Element.
5332	/// If MalformedDecl is not null, and type_identity was ruled out due to being
5333	/// incorrectly structured despite having the correct name, the faulty Decl
5334	/// will be assigned to MalformedDecl.
5335	bool isStdTypeIdentity(QualType Ty, QualType *TypeArgument,
5336	const Decl MalformedDecl = nullptr**);
5337
5338	/// Looks for the std::initializer_list template and instantiates it
5339	/// with Element, or emits an error if it's not found.
5340	///
5341	/// \returns The instantiated template, or null on error.
5342	QualType BuildStdInitializerList(QualType Element, SourceLocation Loc);
5343
5344	/// Looks for the std::type_identity template and instantiates it
5345	/// with Type, or returns a null type if type_identity has not been declared
5346	///
5347	/// \returns The instantiated template, or null if std::type_identity is not
5348	/// declared
5349	QualType tryBuildStdTypeIdentity(QualType Type, SourceLocation Loc);
5350
5351	/// Determine whether Ctor is an initializer-list constructor, as
5352	/// defined in [dcl.init.list]p2.
5353	bool isInitListConstructor(const FunctionDecl *Ctor);
5354
5355	Decl ActOnUsingDirective(Scope CurScope, SourceLocation UsingLoc,
5356	SourceLocation NamespcLoc, CXXScopeSpec &SS,
5357	SourceLocation IdentLoc,
5358	IdentifierInfo *NamespcName,
5359	const ParsedAttributesView &AttrList);
5360
5361	void PushUsingDirective(Scope S, UsingDirectiveDecl UDir);
5362
5363	Decl ActOnNamespaceAliasDef(Scope CurScope, SourceLocation NamespaceLoc,
5364	SourceLocation AliasLoc, IdentifierInfo *Alias,
5365	CXXScopeSpec &SS, SourceLocation IdentLoc,
5366	IdentifierInfo *Ident);
5367
5368	/// Remove decls we can't actually see from a lookup being used to declare
5369	/// shadow using decls.
5370	///
5371	/// \param S - The scope of the potential shadow decl
5372	/// \param Previous - The lookup of a potential shadow decl's name.
5373	void FilterUsingLookup(Scope *S, LookupResult &lookup);
5374
5375	/// Hides a using shadow declaration. This is required by the current
5376	/// using-decl implementation when a resolvable using declaration in a
5377	/// class is followed by a declaration which would hide or override
5378	/// one or more of the using decl's targets; for example:
5379	///
5380	/// struct Base { void foo(int); };
5381	/// struct Derived : Base {
5382	/// using Base::foo;
5383	/// void foo(int);
5384	/// };
5385	///
5386	/// The governing language is C++03 [namespace.udecl]p12:
5387	///
5388	/// When a using-declaration brings names from a base class into a
5389	/// derived class scope, member functions in the derived class
5390	/// override and/or hide member functions with the same name and
5391	/// parameter types in a base class (rather than conflicting).
5392	///
5393	/// There are two ways to implement this:
5394	/// (1) optimistically create shadow decls when they're not hidden
5395	/// by existing declarations, or
5396	/// (2) don't create any shadow decls (or at least don't make them
5397	/// visible) until we've fully parsed/instantiated the class.
5398	/// The problem with (1) is that we might have to retroactively remove
5399	/// a shadow decl, which requires several O(n) operations because the
5400	/// decl structures are (very reasonably) not designed for removal.
5401	/// (2) avoids this but is very fiddly and phase-dependent.
5402	void HideUsingShadowDecl(Scope S, UsingShadowDecl Shadow);
5403
5404	/// Determines whether to create a using shadow decl for a particular
5405	/// decl, given the set of decls existing prior to this using lookup.
5406	bool CheckUsingShadowDecl(BaseUsingDecl BUD, NamedDecl Target,
5407	const LookupResult &PreviousDecls,
5408	UsingShadowDecl *&PrevShadow);
5409
5410	/// Builds a shadow declaration corresponding to a 'using' declaration.
5411	UsingShadowDecl BuildUsingShadowDecl(Scope S, BaseUsingDecl *BUD,
5412	NamedDecl *Target,
5413	UsingShadowDecl *PrevDecl);
5414
5415	/// Checks that the given using declaration is not an invalid
5416	/// redeclaration. Note that this is checking only for the using decl
5417	/// itself, not for any ill-formedness among the UsingShadowDecls.
5418	bool CheckUsingDeclRedeclaration(SourceLocation UsingLoc,
5419	bool HasTypenameKeyword,
5420	const CXXScopeSpec &SS,
5421	SourceLocation NameLoc,
5422	const LookupResult &Previous);
5423
5424	/// Checks that the given nested-name qualifier used in a using decl
5425	/// in the current context is appropriately related to the current
5426	/// scope. If an error is found, diagnoses it and returns true.
5427	/// R is nullptr, if the caller has not (yet) done a lookup, otherwise it's
5428	/// the result of that lookup. UD is likewise nullptr, except when we have an
5429	/// already-populated UsingDecl whose shadow decls contain the same
5430	/// information (i.e. we're instantiating a UsingDecl with non-dependent
5431	/// scope).
5432	bool CheckUsingDeclQualifier(SourceLocation UsingLoc, bool HasTypename,
5433	const CXXScopeSpec &SS,
5434	const DeclarationNameInfo &NameInfo,
5435	SourceLocation NameLoc,
5436	const LookupResult R = nullptr*,
5437	const UsingDecl UD = nullptr*);
5438
5439	/// Builds a using declaration.
5440	///
5441	/// \param IsInstantiation - Whether this call arises from an
5442	/// instantiation of an unresolved using declaration. We treat
5443	/// the lookup differently for these declarations.
5444	NamedDecl BuildUsingDeclaration(Scope S, AccessSpecifier AS,
5445	SourceLocation UsingLoc,
5446	bool HasTypenameKeyword,
5447	SourceLocation TypenameLoc, CXXScopeSpec &SS,
5448	DeclarationNameInfo NameInfo,
5449	SourceLocation EllipsisLoc,
5450	const ParsedAttributesView &AttrList,
5451	bool IsInstantiation, bool IsUsingIfExists);
5452	NamedDecl BuildUsingEnumDeclaration(Scope S, AccessSpecifier AS,
5453	SourceLocation UsingLoc,
5454	SourceLocation EnumLoc,
5455	SourceLocation NameLoc,
5456	TypeSourceInfo EnumType, EnumDecl ED);
5457	NamedDecl BuildUsingPackDecl(NamedDecl InstantiatedFrom,
5458	ArrayRef<NamedDecl *> Expansions);
5459
5460	/// Additional checks for a using declaration referring to a constructor name.
5461	bool CheckInheritingConstructorUsingDecl(UsingDecl *UD);
5462
5463	/// Given a derived-class using shadow declaration for a constructor and the
5464	/// correspnding base class constructor, find or create the implicit
5465	/// synthesized derived class constructor to use for this initialization.
5466	CXXConstructorDecl *
5467	findInheritingConstructor(SourceLocation Loc, CXXConstructorDecl *BaseCtor,
5468	ConstructorUsingShadowDecl *DerivedShadow);
5469
5470	Decl ActOnUsingDeclaration(Scope CurScope, AccessSpecifier AS,
5471	SourceLocation UsingLoc,
5472	SourceLocation TypenameLoc, CXXScopeSpec &SS,
5473	UnqualifiedId &Name, SourceLocation EllipsisLoc,
5474	const ParsedAttributesView &AttrList);
5475	Decl ActOnUsingEnumDeclaration(Scope CurScope, AccessSpecifier AS,
5476	SourceLocation UsingLoc,
5477	SourceLocation EnumLoc, SourceRange TyLoc,
5478	const IdentifierInfo &II, ParsedType Ty,
5479	const CXXScopeSpec &SS);
5480	Decl ActOnAliasDeclaration(Scope CurScope, AccessSpecifier AS,
5481	MultiTemplateParamsArg TemplateParams,
5482	SourceLocation UsingLoc, UnqualifiedId &Name,
5483	const ParsedAttributesView &AttrList,
5484	TypeResult Type, Decl *DeclFromDeclSpec);
5485
5486	/// BuildCXXConstructExpr - Creates a complete call to a constructor,
5487	/// including handling of its default argument expressions.
5488	///
5489	/// \param ConstructKind - a CXXConstructExpr::ConstructionKind
5490	ExprResult BuildCXXConstructExpr(
5491	SourceLocation ConstructLoc, QualType DeclInitType, NamedDecl *FoundDecl,
5492	CXXConstructorDecl *Constructor, MultiExprArg Exprs,
5493	bool HadMultipleCandidates, bool IsListInitialization,
5494	bool IsStdInitListInitialization, bool RequiresZeroInit,
5495	CXXConstructionKind ConstructKind, SourceRange ParenRange);
5496
5497	/// Build a CXXConstructExpr whose constructor has already been resolved if
5498	/// it denotes an inherited constructor.
5499	ExprResult BuildCXXConstructExpr(
5500	SourceLocation ConstructLoc, QualType DeclInitType,
5501	CXXConstructorDecl Constructor, bool* Elidable, MultiExprArg Exprs,
5502	bool HadMultipleCandidates, bool IsListInitialization,
5503	bool IsStdInitListInitialization, bool RequiresZeroInit,
5504	CXXConstructionKind ConstructKind, SourceRange ParenRange);
5505
5506	// FIXME: Can we remove this and have the above BuildCXXConstructExpr check if
5507	// the constructor can be elidable?
5508	ExprResult BuildCXXConstructExpr(
5509	SourceLocation ConstructLoc, QualType DeclInitType, NamedDecl *FoundDecl,
5510	CXXConstructorDecl Constructor, bool* Elidable, MultiExprArg Exprs,
5511	bool HadMultipleCandidates, bool IsListInitialization,
5512	bool IsStdInitListInitialization, bool RequiresZeroInit,
5513	CXXConstructionKind ConstructKind, SourceRange ParenRange);
5514
5515	ExprResult ConvertMemberDefaultInitExpression(FieldDecl FD, Expr InitExpr,
5516	SourceLocation InitLoc);
5517
5518	/// FinalizeVarWithDestructor - Prepare for calling destructor on the
5519	/// constructed variable.
5520	void FinalizeVarWithDestructor(VarDecl VD, CXXRecordDecl DeclInit);
5521
5522	/// Helper class that collects exception specifications for
5523	/// implicitly-declared special member functions.
5524	class ImplicitExceptionSpecification {
5525	// Pointer to allow copying
5526	Sema *Self;
5527	// We order exception specifications thus:
5528	// noexcept is the most restrictive, but is only used in C++11.
5529	// throw() comes next.
5530	// Then a throw(collected exceptions)
5531	// Finally no specification, which is expressed as noexcept(false).
5532	// throw(...) is used instead if any called function uses it.
5533	ExceptionSpecificationType ComputedEST;
5534	llvm::SmallPtrSet<CanQualType, `4`> ExceptionsSeen;
5535	SmallVector<QualType, `4`> Exceptions;
5536
5537	void ClearExceptions() {
5538	ExceptionsSeen.clear();
5539	Exceptions.clear();
5540	}
5541
5542	public:
5543	explicit ImplicitExceptionSpecification(Sema &Self)
5544	: Self(&Self), ComputedEST(EST_BasicNoexcept) {
5545	if (!Self.getLangOpts().CPlusPlus11)
5546	ComputedEST = EST_DynamicNone;
5547	}
5548
5549	/// Get the computed exception specification type.
5550	ExceptionSpecificationType getExceptionSpecType() const {
5551	assert(!isComputedNoexcept(ComputedEST) &&
5552	"noexcept(expr) should not be a possible result");
5553	return ComputedEST;
5554	}
5555
5556	/// The number of exceptions in the exception specification.
5557	unsigned size() const { return Exceptions.size(); }
5558
5559	/// The set of exceptions in the exception specification.
5560	const QualType data() const* { return Exceptions.data(); }
5561
5562	/// Integrate another called method into the collected data.
5563	void CalledDecl(SourceLocation CallLoc, const CXXMethodDecl *Method);
5564
5565	/// Integrate an invoked expression into the collected data.
5566	void CalledExpr(Expr *E) { CalledStmt(S: E); }
5567
5568	/// Integrate an invoked statement into the collected data.
5569	void CalledStmt(Stmt *S);
5570
5571	/// Overwrite an EPI's exception specification with this
5572	/// computed exception specification.
5573	FunctionProtoType::ExceptionSpecInfo getExceptionSpec() const {
5574	FunctionProtoType::ExceptionSpecInfo ESI;
5575	ESI.Type = getExceptionSpecType();
5576	if (ESI.Type == EST_Dynamic) {
5577	ESI.Exceptions = Exceptions;
5578	} else if (ESI.Type == EST_None) {
5579	/// C++11 [except.spec]p14:
5580	/// The exception-specification is noexcept(false) if the set of
5581	/// potential exceptions of the special member function contains "any"
5582	ESI.Type = EST_NoexceptFalse;
5583	ESI.NoexceptExpr =
5584	Self->ActOnCXXBoolLiteral(OpLoc: SourceLocation (), Kind: tok::kw_false).get();
5585	}
5586	return ESI;
5587	}
5588	};
5589
5590	/// Evaluate the implicit exception specification for a defaulted
5591	/// special member function.
5592	void EvaluateImplicitExceptionSpec(SourceLocation Loc, FunctionDecl *FD);
5593
5594	/// Check the given exception-specification and update the
5595	/// exception specification information with the results.
5596	void checkExceptionSpecification(bool IsTopLevel,
5597	ExceptionSpecificationType EST,
5598	ArrayRef<ParsedType> DynamicExceptions,
5599	ArrayRef<SourceRange> DynamicExceptionRanges,
5600	Expr *NoexceptExpr,
5601	SmallVectorImpl<QualType> &Exceptions,
5602	FunctionProtoType::ExceptionSpecInfo &ESI);
5603
5604	/// Add an exception-specification to the given member or friend function
5605	/// (or function template). The exception-specification was parsed
5606	/// after the function itself was declared.
5607	void actOnDelayedExceptionSpecification(
5608	Decl *D, ExceptionSpecificationType EST, SourceRange SpecificationRange,
5609	ArrayRef<ParsedType> DynamicExceptions,
5610	ArrayRef<SourceRange> DynamicExceptionRanges, Expr *NoexceptExpr);
5611
5612	class InheritedConstructorInfo;
5613
5614	/// Determine if a special member function should have a deleted
5615	/// definition when it is defaulted.
5616	bool ShouldDeleteSpecialMember(CXXMethodDecl *MD, CXXSpecialMemberKind CSM,
5617	InheritedConstructorInfo ICI = nullptr*,
5618	bool Diagnose = false);
5619
5620	/// Produce notes explaining why a defaulted function was defined as deleted.
5621	void DiagnoseDeletedDefaultedFunction(FunctionDecl *FD);
5622
5623	/// Declare the implicit default constructor for the given class.
5624	///
5625	/// \param ClassDecl The class declaration into which the implicit
5626	/// default constructor will be added.
5627	///
5628	/// \returns The implicitly-declared default constructor.
5629	CXXConstructorDecl *
5630	DeclareImplicitDefaultConstructor(CXXRecordDecl *ClassDecl);
5631
5632	/// DefineImplicitDefaultConstructor - Checks for feasibility of
5633	/// defining this constructor as the default constructor.
5634	void DefineImplicitDefaultConstructor(SourceLocation CurrentLocation,
5635	CXXConstructorDecl *Constructor);
5636
5637	/// Declare the implicit destructor for the given class.
5638	///
5639	/// \param ClassDecl The class declaration into which the implicit
5640	/// destructor will be added.
5641	///
5642	/// \returns The implicitly-declared destructor.
5643	CXXDestructorDecl DeclareImplicitDestructor(CXXRecordDecl ClassDecl);
5644
5645	/// DefineImplicitDestructor - Checks for feasibility of
5646	/// defining this destructor as the default destructor.
5647	void DefineImplicitDestructor(SourceLocation CurrentLocation,
5648	CXXDestructorDecl *Destructor);
5649
5650	/// Build an exception spec for destructors that don't have one.
5651	///
5652	/// C++11 says that user-defined destructors with no exception spec get one
5653	/// that looks as if the destructor was implicitly declared.
5654	void AdjustDestructorExceptionSpec(CXXDestructorDecl *Destructor);
5655
5656	/// Define the specified inheriting constructor.
5657	void DefineInheritingConstructor(SourceLocation UseLoc,
5658	CXXConstructorDecl *Constructor);
5659
5660	/// Declare the implicit copy constructor for the given class.
5661	///
5662	/// \param ClassDecl The class declaration into which the implicit
5663	/// copy constructor will be added.
5664	///
5665	/// \returns The implicitly-declared copy constructor.
5666	CXXConstructorDecl DeclareImplicitCopyConstructor(CXXRecordDecl ClassDecl);
5667
5668	/// DefineImplicitCopyConstructor - Checks for feasibility of
5669	/// defining this constructor as the copy constructor.
5670	void DefineImplicitCopyConstructor(SourceLocation CurrentLocation,
5671	CXXConstructorDecl *Constructor);
5672
5673	/// Declare the implicit move constructor for the given class.
5674	///
5675	/// \param ClassDecl The Class declaration into which the implicit
5676	/// move constructor will be added.
5677	///
5678	/// \returns The implicitly-declared move constructor, or NULL if it wasn't
5679	/// declared.
5680	CXXConstructorDecl DeclareImplicitMoveConstructor(CXXRecordDecl ClassDecl);
5681
5682	/// DefineImplicitMoveConstructor - Checks for feasibility of
5683	/// defining this constructor as the move constructor.
5684	void DefineImplicitMoveConstructor(SourceLocation CurrentLocation,
5685	CXXConstructorDecl *Constructor);
5686
5687	/// Declare the implicit copy assignment operator for the given class.
5688	///
5689	/// \param ClassDecl The class declaration into which the implicit
5690	/// copy assignment operator will be added.
5691	///
5692	/// \returns The implicitly-declared copy assignment operator.
5693	CXXMethodDecl DeclareImplicitCopyAssignment(CXXRecordDecl ClassDecl);
5694
5695	/// Defines an implicitly-declared copy assignment operator.
5696	void DefineImplicitCopyAssignment(SourceLocation CurrentLocation,
5697	CXXMethodDecl *MethodDecl);
5698
5699	/// Declare the implicit move assignment operator for the given class.
5700	///
5701	/// \param ClassDecl The Class declaration into which the implicit
5702	/// move assignment operator will be added.
5703	///
5704	/// \returns The implicitly-declared move assignment operator, or NULL if it
5705	/// wasn't declared.
5706	CXXMethodDecl DeclareImplicitMoveAssignment(CXXRecordDecl ClassDecl);
5707
5708	/// Defines an implicitly-declared move assignment operator.
5709	void DefineImplicitMoveAssignment(SourceLocation CurrentLocation,
5710	CXXMethodDecl *MethodDecl);
5711
5712	/// Check a completed declaration of an implicit special member.
5713	void CheckImplicitSpecialMemberDeclaration(Scope S, FunctionDecl FD);
5714
5715	/// Determine whether the given function is an implicitly-deleted
5716	/// special member function.
5717	bool isImplicitlyDeleted(FunctionDecl *FD);
5718
5719	/// Check whether 'this' shows up in the type of a static member
5720	/// function after the (naturally empty) cv-qualifier-seq would be.
5721	///
5722	/// \returns true if an error occurred.
5723	bool checkThisInStaticMemberFunctionType(CXXMethodDecl *Method);
5724
5725	/// Whether this' shows up in the exception specification of a static
5726	/// member function.
5727	bool checkThisInStaticMemberFunctionExceptionSpec(CXXMethodDecl *Method);
5728
5729	/// Check whether 'this' shows up in the attributes of the given
5730	/// static member function.
5731	///
5732	/// \returns true if an error occurred.
5733	bool checkThisInStaticMemberFunctionAttributes(CXXMethodDecl *Method);
5734
5735	bool CheckImmediateEscalatingFunctionDefinition(
5736	FunctionDecl FD, const* sema::FunctionScopeInfo *FSI);
5737
5738	void DiagnoseImmediateEscalatingReason(FunctionDecl *FD);
5739
5740	/// Given a constructor and the set of arguments provided for the
5741	/// constructor, convert the arguments and add any required default arguments
5742	/// to form a proper call to this constructor.
5743	///
5744	/// \returns true if an error occurred, false otherwise.
5745	bool CompleteConstructorCall(CXXConstructorDecl *Constructor,
5746	QualType DeclInitType, MultiExprArg ArgsPtr,
5747	SourceLocation Loc,
5748	SmallVectorImpl<Expr *> &ConvertedArgs,
5749	bool AllowExplicit = false,
5750	bool IsListInitialization = false);
5751
5752	/// ActOnCXXEnterDeclInitializer - Invoked when we are about to parse an
5753	/// initializer for the declaration 'Dcl'.
5754	/// After this method is called, according to [C++ 3.4.1p13], if 'Dcl' is a
5755	/// static data member of class X, names should be looked up in the scope of
5756	/// class X.
5757	void ActOnCXXEnterDeclInitializer(Scope S, Decl Dcl);
5758
5759	/// ActOnCXXExitDeclInitializer - Invoked after we are finished parsing an
5760	/// initializer for the declaration 'Dcl'.
5761	void ActOnCXXExitDeclInitializer(Scope S, Decl Dcl);
5762
5763	/// Define the "body" of the conversion from a lambda object to a
5764	/// function pointer.
5765	///
5766	/// This routine doesn't actually define a sensible body; rather, it fills
5767	/// in the initialization expression needed to copy the lambda object into
5768	/// the block, and IR generation actually generates the real body of the
5769	/// block pointer conversion.
5770	void
5771	DefineImplicitLambdaToFunctionPointerConversion(SourceLocation CurrentLoc,
5772	CXXConversionDecl *Conv);
5773
5774	/// Define the "body" of the conversion from a lambda object to a
5775	/// block pointer.
5776	///
5777	/// This routine doesn't actually define a sensible body; rather, it fills
5778	/// in the initialization expression needed to copy the lambda object into
5779	/// the block, and IR generation actually generates the real body of the
5780	/// block pointer conversion.
5781	void DefineImplicitLambdaToBlockPointerConversion(SourceLocation CurrentLoc,
5782	CXXConversionDecl *Conv);
5783
5784	/// ActOnStartLinkageSpecification - Parsed the beginning of a C++
5785	/// linkage specification, including the language and (if present)
5786	/// the '{'. ExternLoc is the location of the 'extern', Lang is the
5787	/// language string literal. LBraceLoc, if valid, provides the location of
5788	/// the '{' brace. Otherwise, this linkage specification does not
5789	/// have any braces.
5790	Decl ActOnStartLinkageSpecification(Scope S, SourceLocation ExternLoc,
5791	Expr *LangStr, SourceLocation LBraceLoc);
5792
5793	/// ActOnFinishLinkageSpecification - Complete the definition of
5794	/// the C++ linkage specification LinkageSpec. If RBraceLoc is
5795	/// valid, it's the position of the closing '}' brace in a linkage
5796	/// specification that uses braces.
5797	Decl ActOnFinishLinkageSpecification(Scope S, Decl *LinkageSpec,
5798	SourceLocation RBraceLoc);
5799
5800	//===--------------------------------------------------------------------===//
5801	// C++ Classes
5802	//
5803
5804	/// Get the class that is directly named by the current context. This is the
5805	/// class for which an unqualified-id in this scope could name a constructor
5806	/// or destructor.
5807	///
5808	/// If the scope specifier denotes a class, this will be that class.
5809	/// If the scope specifier is empty, this will be the class whose
5810	/// member-specification we are currently within. Otherwise, there
5811	/// is no such class.
5812	CXXRecordDecl getCurrentClass(Scope S, const CXXScopeSpec *SS);
5813
5814	/// isCurrentClassName - Determine whether the identifier II is the
5815	/// name of the class type currently being defined. In the case of
5816	/// nested classes, this will only return true if II is the name of
5817	/// the innermost class.
5818	bool isCurrentClassName(const IdentifierInfo &II, Scope *S,
5819	const CXXScopeSpec SS = nullptr*);
5820
5821	/// Determine whether the identifier II is a typo for the name of
5822	/// the class type currently being defined. If so, update it to the identifier
5823	/// that should have been used.
5824	bool isCurrentClassNameTypo(IdentifierInfo &II, const* CXXScopeSpec *SS);
5825
5826	/// ActOnAccessSpecifier - Parsed an access specifier followed by a colon.
5827	bool ActOnAccessSpecifier(AccessSpecifier Access, SourceLocation ASLoc,
5828	SourceLocation ColonLoc,
5829	const ParsedAttributesView &Attrs);
5830
5831	/// ActOnCXXMemberDeclarator - This is invoked when a C++ class member
5832	/// declarator is parsed. 'AS' is the access specifier, 'BW' specifies the
5833	/// bitfield width if there is one, 'InitExpr' specifies the initializer if
5834	/// one has been parsed, and 'InitStyle' is set if an in-class initializer is
5835	/// present (but parsing it has been deferred).
5836	NamedDecl *
5837	ActOnCXXMemberDeclarator(Scope *S, AccessSpecifier AS, Declarator &D,
5838	MultiTemplateParamsArg TemplateParameterLists,
5839	Expr BitfieldWidth, const* VirtSpecifiers &VS,
5840	InClassInitStyle InitStyle);
5841
5842	/// Enter a new C++ default initializer scope. After calling this, the
5843	/// caller must call \ref ActOnFinishCXXInClassMemberInitializer, even if
5844	/// parsing or instantiating the initializer failed.
5845	void ActOnStartCXXInClassMemberInitializer();
5846
5847	/// This is invoked after parsing an in-class initializer for a
5848	/// non-static C++ class member, and after instantiating an in-class
5849	/// initializer in a class template. Such actions are deferred until the class
5850	/// is complete.
5851	void ActOnFinishCXXInClassMemberInitializer(Decl *VarDecl,
5852	SourceLocation EqualLoc,
5853	ExprResult Init);
5854
5855	/// Handle a C++ member initializer using parentheses syntax.
5856	MemInitResult
5857	ActOnMemInitializer(Decl ConstructorD, Scope S, CXXScopeSpec &SS,
5858	IdentifierInfo *MemberOrBase, ParsedType TemplateTypeTy,
5859	const DeclSpec &DS, SourceLocation IdLoc,
5860	SourceLocation LParenLoc, ArrayRef<Expr *> Args,
5861	SourceLocation RParenLoc, SourceLocation EllipsisLoc);
5862
5863	/// Handle a C++ member initializer using braced-init-list syntax.
5864	MemInitResult ActOnMemInitializer(Decl ConstructorD, Scope S,
5865	CXXScopeSpec &SS,
5866	IdentifierInfo *MemberOrBase,
5867	ParsedType TemplateTypeTy,
5868	const DeclSpec &DS, SourceLocation IdLoc,
5869	Expr *InitList, SourceLocation EllipsisLoc);
5870
5871	/// Handle a C++ member initializer.
5872	MemInitResult BuildMemInitializer(Decl ConstructorD, Scope S,
5873	CXXScopeSpec &SS,
5874	IdentifierInfo *MemberOrBase,
5875	ParsedType TemplateTypeTy,
5876	const DeclSpec &DS, SourceLocation IdLoc,
5877	Expr *Init, SourceLocation EllipsisLoc);
5878
5879	MemInitResult BuildMemberInitializer(ValueDecl Member, Expr Init,
5880	SourceLocation IdLoc);
5881
5882	MemInitResult BuildBaseInitializer(QualType BaseType,
5883	TypeSourceInfo BaseTInfo, Expr Init,
5884	CXXRecordDecl *ClassDecl,
5885	SourceLocation EllipsisLoc);
5886
5887	MemInitResult BuildDelegatingInitializer(TypeSourceInfo TInfo, Expr Init,
5888	CXXRecordDecl *ClassDecl);
5889
5890	bool SetDelegatingInitializer(CXXConstructorDecl *Constructor,
5891	CXXCtorInitializer *Initializer);
5892
5893	bool SetCtorInitializers(CXXConstructorDecl Constructor, bool* AnyErrors,
5894	ArrayRef<CXXCtorInitializer *> Initializers = {});
5895
5896	/// MarkBaseAndMemberDestructorsReferenced - Given a record decl,
5897	/// mark all the non-trivial destructors of its members and bases as
5898	/// referenced.
5899	void MarkBaseAndMemberDestructorsReferenced(SourceLocation Loc,
5900	CXXRecordDecl *Record);
5901
5902	/// Mark destructors of virtual bases of this class referenced. In the Itanium
5903	/// C++ ABI, this is done when emitting a destructor for any non-abstract
5904	/// class. In the Microsoft C++ ABI, this is done any time a class's
5905	/// destructor is referenced.
5906	void MarkVirtualBaseDestructorsReferenced(
5907	SourceLocation Location, CXXRecordDecl *ClassDecl,
5908	llvm::SmallPtrSetImpl<const CXXRecordDecl > DirectVirtualBases =
5909	nullptr);
5910
5911	/// Do semantic checks to allow the complete destructor variant to be emitted
5912	/// when the destructor is defined in another translation unit. In the Itanium
5913	/// C++ ABI, destructor variants are emitted together. In the MS C++ ABI, they
5914	/// can be emitted in separate TUs. To emit the complete variant, run a subset
5915	/// of the checks performed when emitting a regular destructor.
5916	void CheckCompleteDestructorVariant(SourceLocation CurrentLocation,
5917	CXXDestructorDecl *Dtor);
5918
5919	/// The list of classes whose vtables have been used within
5920	/// this translation unit, and the source locations at which the
5921	/// first use occurred.
5922	typedef std::pair<CXXRecordDecl *, SourceLocation> VTableUse;
5923
5924	/// The list of vtables that are required but have not yet been
5925	/// materialized.
5926	SmallVector<VTableUse, `16`> VTableUses;
5927
5928	/// The set of classes whose vtables have been used within
5929	/// this translation unit, and a bit that will be true if the vtable is
5930	/// required to be emitted (otherwise, it should be emitted only if needed
5931	/// by code generation).
5932	llvm::DenseMap<CXXRecordDecl , bool*> VTablesUsed;
5933
5934	/// Load any externally-stored vtable uses.
5935	void LoadExternalVTableUses();
5936
5937	/// Note that the vtable for the given class was used at the
5938	/// given location.
5939	void MarkVTableUsed(SourceLocation Loc, CXXRecordDecl *Class,
5940	bool DefinitionRequired = false);
5941
5942	/// Mark the exception specifications of all virtual member functions
5943	/// in the given class as needed.
5944	void MarkVirtualMemberExceptionSpecsNeeded(SourceLocation Loc,
5945	const CXXRecordDecl *RD);
5946
5947	/// MarkVirtualMembersReferenced - Will mark all members of the given
5948	/// CXXRecordDecl referenced.
5949	void MarkVirtualMembersReferenced(SourceLocation Loc, const CXXRecordDecl *RD,
5950	bool ConstexprOnly = false);
5951
5952	/// Define all of the vtables that have been used in this
5953	/// translation unit and reference any virtual members used by those
5954	/// vtables.
5955	///
5956	/// \returns true if any work was done, false otherwise.
5957	bool DefineUsedVTables();
5958
5959	/// AddImplicitlyDeclaredMembersToClass - Adds any implicitly-declared
5960	/// special functions, such as the default constructor, copy
5961	/// constructor, or destructor, to the given C++ class (C++
5962	/// [special]p1). This routine can only be executed just before the
5963	/// definition of the class is complete.
5964	void AddImplicitlyDeclaredMembersToClass(CXXRecordDecl *ClassDecl);
5965
5966	/// ActOnMemInitializers - Handle the member initializers for a constructor.
5967	void ActOnMemInitializers(Decl *ConstructorDecl, SourceLocation ColonLoc,
5968	ArrayRef<CXXCtorInitializer *> MemInits,
5969	bool AnyErrors);
5970
5971	/// Check class-level dllimport/dllexport attribute. The caller must
5972	/// ensure that referenceDLLExportedClassMethods is called some point later
5973	/// when all outer classes of Class are complete.
5974	void checkClassLevelDLLAttribute(CXXRecordDecl *Class);
5975	void checkClassLevelCodeSegAttribute(CXXRecordDecl *Class);
5976
5977	void referenceDLLExportedClassMethods();
5978
5979	/// Perform propagation of DLL attributes from a derived class to a
5980	/// templated base class for MS compatibility.
5981	void propagateDLLAttrToBaseClassTemplate(
5982	CXXRecordDecl Class, Attr ClassAttr,
5983	ClassTemplateSpecializationDecl *BaseTemplateSpec,
5984	SourceLocation BaseLoc);
5985
5986	/// Perform semantic checks on a class definition that has been
5987	/// completing, introducing implicitly-declared members, checking for
5988	/// abstract types, etc.
5989	///
5990	/// \param S The scope in which the class was parsed. Null if we didn't just
5991	/// parse a class definition.
5992	/// \param Record The completed class.
5993	void CheckCompletedCXXClass(Scope S, CXXRecordDecl Record);
5994
5995	/// Check that the C++ class annoated with "trivial_abi" satisfies all the
5996	/// conditions that are needed for the attribute to have an effect.
5997	void checkIllFormedTrivialABIStruct(CXXRecordDecl &RD);
5998
5999	/// Check that VTable Pointer authentication is only being set on the first
6000	/// first instantiation of the vtable
6001	void checkIncorrectVTablePointerAuthenticationAttribute(CXXRecordDecl &RD);
6002
6003	void ActOnFinishCXXMemberSpecification(Scope *S, SourceLocation RLoc,
6004	Decl *TagDecl, SourceLocation LBrac,
6005	SourceLocation RBrac,
6006	const ParsedAttributesView &AttrList);
6007
6008	/// Perform any semantic analysis which needs to be delayed until all
6009	/// pending class member declarations have been parsed.
6010	void ActOnFinishCXXMemberDecls();
6011	void ActOnFinishCXXNonNestedClass();
6012
6013	/// This is used to implement the constant expression evaluation part of the
6014	/// attribute enable_if extension. There is nothing in standard C++ which
6015	/// would require reentering parameters.
6016	void ActOnReenterCXXMethodParameter(Scope S, ParmVarDecl Param);
6017	unsigned ActOnReenterTemplateScope(Decl *Template,
6018	llvm::function_ref<Scope *()> EnterScope);
6019	void ActOnStartDelayedMemberDeclarations(Scope S, Decl Record);
6020
6021	/// ActOnStartDelayedCXXMethodDeclaration - We have completed
6022	/// parsing a top-level (non-nested) C++ class, and we are now
6023	/// parsing those parts of the given Method declaration that could
6024	/// not be parsed earlier (C++ [class.mem]p2), such as default
6025	/// arguments. This action should enter the scope of the given
6026	/// Method declaration as if we had just parsed the qualified method
6027	/// name. However, it should not bring the parameters into scope;
6028	/// that will be performed by ActOnDelayedCXXMethodParameter.
6029	void ActOnStartDelayedCXXMethodDeclaration(Scope S, Decl Method);
6030	void ActOnDelayedCXXMethodParameter(Scope S, Decl Param);
6031	void ActOnFinishDelayedMemberDeclarations(Scope S, Decl Record);
6032
6033	/// ActOnFinishDelayedCXXMethodDeclaration - We have finished
6034	/// processing the delayed method declaration for Method. The method
6035	/// declaration is now considered finished. There may be a separate
6036	/// ActOnStartOfFunctionDef action later (not necessarily
6037	/// immediately!) for this method, if it was also defined inside the
6038	/// class body.
6039	void ActOnFinishDelayedCXXMethodDeclaration(Scope S, Decl Method);
6040	void ActOnFinishDelayedMemberInitializers(Decl *Record);
6041
6042	enum class StringEvaluationContext { StaticAssert = `0`, Asm = `1` };
6043
6044	bool EvaluateAsString(Expr *Message, APValue &Result, ASTContext &Ctx,
6045	StringEvaluationContext EvalContext,
6046	bool ErrorOnInvalidMessage);
6047	bool EvaluateAsString(Expr *Message, std::string &Result, ASTContext &Ctx,
6048	StringEvaluationContext EvalContext,
6049	bool ErrorOnInvalidMessage);
6050
6051	Decl *ActOnStaticAssertDeclaration(SourceLocation StaticAssertLoc,
6052	Expr AssertExpr, Expr AssertMessageExpr,
6053	SourceLocation RParenLoc);
6054	Decl *BuildStaticAssertDeclaration(SourceLocation StaticAssertLoc,
6055	Expr AssertExpr, Expr AssertMessageExpr,
6056	SourceLocation RParenLoc, bool Failed);
6057
6058	/// Try to print more useful information about a failed static_assert
6059	/// with expression \E
6060	void DiagnoseStaticAssertDetails(const Expr *E);
6061
6062	/// If E represents a built-in type trait, or a known standard type trait,
6063	/// try to print more information about why the type type-trait failed.
6064	/// This assumes we already evaluated the expression to a false boolean value.
6065	void DiagnoseTypeTraitDetails(const Expr *E);
6066
6067	/// Handle a friend type declaration. This works in tandem with
6068	/// ActOnTag.
6069	///
6070	/// Notes on friend class templates:
6071	///
6072	/// We generally treat friend class declarations as if they were
6073	/// declaring a class. So, for example, the elaborated type specifier
6074	/// in a friend declaration is required to obey the restrictions of a
6075	/// class-head (i.e. no typedefs in the scope chain), template
6076	/// parameters are required to match up with simple template-ids, &c.
6077	/// However, unlike when declaring a template specialization, it's
6078	/// okay to refer to a template specialization without an empty
6079	/// template parameter declaration, e.g.
6080	/// friend class A<T>::B<unsigned>;
6081	/// We permit this as a special case; if there are any template
6082	/// parameters present at all, require proper matching, i.e.
6083	/// template <> template \<class T> friend class A<int>::B;
6084	Decl ActOnFriendTypeDecl(Scope S, const DeclSpec &DS,
6085	MultiTemplateParamsArg TemplateParams,
6086	SourceLocation EllipsisLoc);
6087	NamedDecl ActOnFriendFunctionDecl(Scope S, Declarator &D,
6088	MultiTemplateParamsArg TemplateParams);
6089
6090	/// CheckConstructorDeclarator - Called by ActOnDeclarator to check
6091	/// the well-formedness of the constructor declarator @p D with type @p
6092	/// R. If there are any errors in the declarator, this routine will
6093	/// emit diagnostics and set the invalid bit to true. In any case, the type
6094	/// will be updated to reflect a well-formed type for the constructor and
6095	/// returned.
6096	QualType CheckConstructorDeclarator(Declarator &D, QualType R,
6097	StorageClass &SC);
6098
6099	/// CheckConstructor - Checks a fully-formed constructor for
6100	/// well-formedness, issuing any diagnostics required. Returns true if
6101	/// the constructor declarator is invalid.
6102	void CheckConstructor(CXXConstructorDecl *Constructor);
6103
6104	/// CheckDestructorDeclarator - Called by ActOnDeclarator to check
6105	/// the well-formednes of the destructor declarator @p D with type @p
6106	/// R. If there are any errors in the declarator, this routine will
6107	/// emit diagnostics and set the declarator to invalid. Even if this happens,
6108	/// will be updated to reflect a well-formed type for the destructor and
6109	/// returned.
6110	QualType CheckDestructorDeclarator(Declarator &D, QualType R,
6111	StorageClass &SC);
6112
6113	/// CheckDestructor - Checks a fully-formed destructor definition for
6114	/// well-formedness, issuing any diagnostics required. Returns true
6115	/// on error.
6116	bool CheckDestructor(CXXDestructorDecl *Destructor);
6117
6118	/// CheckConversionDeclarator - Called by ActOnDeclarator to check the
6119	/// well-formednes of the conversion function declarator @p D with
6120	/// type @p R. If there are any errors in the declarator, this routine
6121	/// will emit diagnostics and return true. Otherwise, it will return
6122	/// false. Either way, the type @p R will be updated to reflect a
6123	/// well-formed type for the conversion operator.
6124	void CheckConversionDeclarator(Declarator &D, QualType &R, StorageClass &SC);
6125
6126	/// ActOnConversionDeclarator - Called by ActOnDeclarator to complete
6127	/// the declaration of the given C++ conversion function. This routine
6128	/// is responsible for recording the conversion function in the C++
6129	/// class, if possible.
6130	Decl ActOnConversionDeclarator(CXXConversionDecl Conversion);
6131
6132	/// Check the validity of a declarator that we parsed for a deduction-guide.
6133	/// These aren't actually declarators in the grammar, so we need to check that
6134	/// the user didn't specify any pieces that are not part of the
6135	/// deduction-guide grammar. Return true on invalid deduction-guide.
6136	bool CheckDeductionGuideDeclarator(Declarator &D, QualType &R,
6137	StorageClass &SC);
6138
6139	void CheckExplicitlyDefaultedFunction(Scope S, FunctionDecl MD);
6140
6141	bool CheckExplicitlyDefaultedSpecialMember(CXXMethodDecl *MD,
6142	CXXSpecialMemberKind CSM,
6143	SourceLocation DefaultLoc);
6144	void CheckDelayedMemberExceptionSpecs();
6145
6146	/// Kinds of defaulted comparison operator functions.
6147	enum class DefaultedComparisonKind : unsigned char {
6148	/// This is not a defaultable comparison operator.
6149	None,
6150	/// This is an operator== that should be implemented as a series of
6151	/// subobject comparisons.
6152	Equal,
6153	/// This is an operator<=> that should be implemented as a series of
6154	/// subobject comparisons.
6155	ThreeWay,
6156	/// This is an operator!= that should be implemented as a rewrite in terms
6157	/// of a == comparison.
6158	NotEqual,
6159	/// This is an <, <=, >, or >= that should be implemented as a rewrite in
6160	/// terms of a <=> comparison.
6161	Relational,
6162	};
6163
6164	bool CheckExplicitlyDefaultedComparison(Scope S, FunctionDecl MD,
6165	DefaultedComparisonKind DCK);
6166	void DeclareImplicitEqualityComparison(CXXRecordDecl *RD,
6167	FunctionDecl *Spaceship);
6168	void DefineDefaultedComparison(SourceLocation Loc, FunctionDecl *FD,
6169	DefaultedComparisonKind DCK);
6170
6171	void CheckExplicitObjectMemberFunction(Declarator &D, DeclarationName Name,
6172	QualType R, bool IsLambda,
6173	DeclContext DC = nullptr*);
6174	void CheckExplicitObjectMemberFunction(DeclContext *DC, Declarator &D,
6175	DeclarationName Name, QualType R);
6176	void CheckExplicitObjectLambda(Declarator &D);
6177
6178	//===--------------------------------------------------------------------===//
6179	// C++ Derived Classes
6180	//
6181
6182	/// Check the validity of a C++ base class specifier.
6183	///
6184	/// \returns a new CXXBaseSpecifier if well-formed, emits diagnostics
6185	/// and returns NULL otherwise.
6186	CXXBaseSpecifier CheckBaseSpecifier(CXXRecordDecl Class,
6187	SourceRange SpecifierRange, bool Virtual,
6188	AccessSpecifier Access,
6189	TypeSourceInfo *TInfo,
6190	SourceLocation EllipsisLoc);
6191
6192	/// ActOnBaseSpecifier - Parsed a base specifier. A base specifier is
6193	/// one entry in the base class list of a class specifier, for
6194	/// example:
6195	/// class foo : public bar, virtual private baz {
6196	/// 'public bar' and 'virtual private baz' are each base-specifiers.
6197	BaseResult ActOnBaseSpecifier(Decl *classdecl, SourceRange SpecifierRange,
6198	const ParsedAttributesView &Attrs, bool Virtual,
6199	AccessSpecifier Access, ParsedType basetype,
6200	SourceLocation BaseLoc,
6201	SourceLocation EllipsisLoc);
6202
6203	/// Performs the actual work of attaching the given base class
6204	/// specifiers to a C++ class.
6205	bool AttachBaseSpecifiers(CXXRecordDecl *Class,
6206	MutableArrayRef<CXXBaseSpecifier *> Bases);
6207
6208	/// ActOnBaseSpecifiers - Attach the given base specifiers to the
6209	/// class, after checking whether there are any duplicate base
6210	/// classes.
6211	void ActOnBaseSpecifiers(Decl *ClassDecl,
6212	MutableArrayRef<CXXBaseSpecifier *> Bases);
6213
6214	/// Determine whether the type \p Derived is a C++ class that is
6215	/// derived from the type \p Base.
6216	bool IsDerivedFrom(SourceLocation Loc, CXXRecordDecl *Derived,
6217	CXXRecordDecl *Base, CXXBasePaths &Paths);
6218	bool IsDerivedFrom(SourceLocation Loc, CXXRecordDecl *Derived,
6219	CXXRecordDecl *Base);
6220	bool IsDerivedFrom(SourceLocation Loc, QualType Derived, QualType Base);
6221	bool IsDerivedFrom(SourceLocation Loc, QualType Derived, QualType Base,
6222	CXXBasePaths &Paths);
6223
6224	// FIXME: I don't like this name.
6225	void BuildBasePathArray(const CXXBasePaths &Paths, CXXCastPath &BasePath);
6226
6227	bool CheckDerivedToBaseConversion(QualType Derived, QualType Base,
6228	SourceLocation Loc, SourceRange Range,
6229	CXXCastPath BasePath = nullptr*,
6230	bool IgnoreAccess = false);
6231
6232	/// CheckDerivedToBaseConversion - Check whether the Derived-to-Base
6233	/// conversion (where Derived and Base are class types) is
6234	/// well-formed, meaning that the conversion is unambiguous (and
6235	/// that all of the base classes are accessible). Returns true
6236	/// and emits a diagnostic if the code is ill-formed, returns false
6237	/// otherwise. Loc is the location where this routine should point to
6238	/// if there is an error, and Range is the source range to highlight
6239	/// if there is an error.
6240	///
6241	/// If either InaccessibleBaseID or AmbiguousBaseConvID are 0, then the
6242	/// diagnostic for the respective type of error will be suppressed, but the
6243	/// check for ill-formed code will still be performed.
6244	bool CheckDerivedToBaseConversion(QualType Derived, QualType Base,
6245	unsigned InaccessibleBaseID,
6246	unsigned AmbiguousBaseConvID,
6247	SourceLocation Loc, SourceRange Range,
6248	DeclarationName Name, CXXCastPath *BasePath,
6249	bool IgnoreAccess = false);
6250
6251	/// Builds a string representing ambiguous paths from a
6252	/// specific derived class to different subobjects of the same base
6253	/// class.
6254	///
6255	/// This function builds a string that can be used in error messages
6256	/// to show the different paths that one can take through the
6257	/// inheritance hierarchy to go from the derived class to different
6258	/// subobjects of a base class. The result looks something like this:
6259	/// @code
6260	/// struct D -> struct B -> struct A
6261	/// struct D -> struct C -> struct A
6262	/// @endcode
6263	std::string getAmbiguousPathsDisplayString(CXXBasePaths &Paths);
6264
6265	bool CheckOverridingFunctionAttributes(CXXMethodDecl *New,
6266	const CXXMethodDecl *Old);
6267
6268	/// CheckOverridingFunctionReturnType - Checks whether the return types are
6269	/// covariant, according to C++ [class.virtual]p5.
6270	bool CheckOverridingFunctionReturnType(const CXXMethodDecl *New,
6271	const CXXMethodDecl *Old);
6272
6273	// Check that the overriding method has no explicit object parameter.
6274	bool CheckExplicitObjectOverride(CXXMethodDecl *New,
6275	const CXXMethodDecl *Old);
6276
6277	/// Mark the given method pure.
6278	///
6279	/// \param Method the method to be marked pure.
6280	///
6281	/// \param InitRange the source range that covers the "0" initializer.
6282	bool CheckPureMethod(CXXMethodDecl *Method, SourceRange InitRange);
6283
6284	/// CheckOverrideControl - Check C++11 override control semantics.
6285	void CheckOverrideControl(NamedDecl *D);
6286
6287	/// DiagnoseAbsenceOfOverrideControl - Diagnose if 'override' keyword was
6288	/// not used in the declaration of an overriding method.
6289	void DiagnoseAbsenceOfOverrideControl(NamedDecl D, bool* Inconsistent);
6290
6291	/// CheckIfOverriddenFunctionIsMarkedFinal - Checks whether a virtual member
6292	/// function overrides a virtual member function marked 'final', according to
6293	/// C++11 [class.virtual]p4.
6294	bool CheckIfOverriddenFunctionIsMarkedFinal(const CXXMethodDecl *New,
6295	const CXXMethodDecl *Old);
6296
6297	enum AbstractDiagSelID {
6298	AbstractNone = -`1`,
6299	AbstractReturnType,
6300	AbstractParamType,
6301	AbstractVariableType,
6302	AbstractFieldType,
6303	AbstractIvarType,
6304	AbstractSynthesizedIvarType,
6305	AbstractArrayType
6306	};
6307
6308	struct TypeDiagnoser;
6309
6310	bool isAbstractType(SourceLocation Loc, QualType T);
6311	bool RequireNonAbstractType(SourceLocation Loc, QualType T,
6312	TypeDiagnoser &Diagnoser);
6313	template <typename... Ts>
6314	bool RequireNonAbstractType(SourceLocation Loc, QualType T, unsigned DiagID,
6315	const Ts &...Args) {
6316	BoundTypeDiagnoser<Ts...> Diagnoser(DiagID, Args...);
6317	return RequireNonAbstractType(Loc, T, Diagnoser);
6318	}
6319
6320	void DiagnoseAbstractType(const CXXRecordDecl *RD);
6321
6322	//===--------------------------------------------------------------------===//
6323	// C++ Overloaded Operators [C++ 13.5]
6324	//
6325
6326	/// CheckOverloadedOperatorDeclaration - Check whether the declaration
6327	/// of this overloaded operator is well-formed. If so, returns false;
6328	/// otherwise, emits appropriate diagnostics and returns true.
6329	bool CheckOverloadedOperatorDeclaration(FunctionDecl *FnDecl);
6330
6331	/// CheckLiteralOperatorDeclaration - Check whether the declaration
6332	/// of this literal operator function is well-formed. If so, returns
6333	/// false; otherwise, emits appropriate diagnostics and returns true.
6334	bool CheckLiteralOperatorDeclaration(FunctionDecl *FnDecl);
6335
6336	/// ActOnExplicitBoolSpecifier - Build an ExplicitSpecifier from an expression
6337	/// found in an explicit(bool) specifier.
6338	ExplicitSpecifier ActOnExplicitBoolSpecifier(Expr *E);
6339
6340	/// tryResolveExplicitSpecifier - Attempt to resolve the explict specifier.
6341	/// Returns true if the explicit specifier is now resolved.
6342	bool tryResolveExplicitSpecifier(ExplicitSpecifier &ExplicitSpec);
6343
6344	/// ActOnCXXConditionDeclarationExpr - Parsed a condition declaration of a
6345	/// C++ if/switch/while/for statement.
6346	/// e.g: "if (int x = f()) {...}"
6347	DeclResult ActOnCXXConditionDeclaration(Scope *S, Declarator &D);
6348
6349	// Emitting members of dllexported classes is delayed until the class
6350	// (including field initializers) is fully parsed.
6351	SmallVector<CXXRecordDecl *, `4`> DelayedDllExportClasses;
6352	SmallVector<CXXMethodDecl *, `4`> DelayedDllExportMemberFunctions;
6353
6354	/// Merge the exception specifications of two variable declarations.
6355	///
6356	/// This is called when there's a redeclaration of a VarDecl. The function
6357	/// checks if the redeclaration might have an exception specification and
6358	/// validates compatibility and merges the specs if necessary.
6359	void MergeVarDeclExceptionSpecs(VarDecl New, VarDecl Old);
6360
6361	/// MergeCXXFunctionDecl - Merge two declarations of the same C++
6362	/// function, once we already know that they have the same
6363	/// type. Subroutine of MergeFunctionDecl. Returns true if there was an
6364	/// error, false otherwise.
6365	bool MergeCXXFunctionDecl(FunctionDecl New, FunctionDecl Old, Scope *S);
6366
6367	/// Helpers for dealing with blocks and functions.
6368	void CheckCXXDefaultArguments(FunctionDecl *FD);
6369
6370	/// CheckExtraCXXDefaultArguments - Check for any extra default
6371	/// arguments in the declarator, which is not a function declaration
6372	/// or definition and therefore is not permitted to have default
6373	/// arguments. This routine should be invoked for every declarator
6374	/// that is not a function declaration or definition.
6375	void CheckExtraCXXDefaultArguments(Declarator &D);
6376
6377	CXXSpecialMemberKind getSpecialMember(const CXXMethodDecl *MD) {
6378	return getDefaultedFunctionKind(FD: MD).asSpecialMember();
6379	}
6380
6381	/// Perform semantic analysis for the variable declaration that
6382	/// occurs within a C++ catch clause, returning the newly-created
6383	/// variable.
6384	VarDecl BuildExceptionDeclaration(Scope S, TypeSourceInfo *TInfo,
6385	SourceLocation StartLoc,
6386	SourceLocation IdLoc,
6387	const IdentifierInfo *Id);
6388
6389	/// ActOnExceptionDeclarator - Parsed the exception-declarator in a C++ catch
6390	/// handler.
6391	Decl ActOnExceptionDeclarator(Scope S, Declarator &D);
6392
6393	void DiagnoseReturnInConstructorExceptionHandler(CXXTryStmt *TryBlock);
6394
6395	/// Handle a friend tag declaration where the scope specifier was
6396	/// templated.
6397	DeclResult ActOnTemplatedFriendTag(Scope *S, SourceLocation FriendLoc,
6398	unsigned TagSpec, SourceLocation TagLoc,
6399	CXXScopeSpec &SS, IdentifierInfo *Name,
6400	SourceLocation NameLoc,
6401	SourceLocation EllipsisLoc,
6402	const ParsedAttributesView &Attr,
6403	MultiTemplateParamsArg TempParamLists);
6404
6405	MSPropertyDecl HandleMSProperty(Scope S, RecordDecl *TagD,
6406	SourceLocation DeclStart, Declarator &D,
6407	Expr *BitfieldWidth,
6408	InClassInitStyle InitStyle,
6409	AccessSpecifier AS,
6410	const ParsedAttr &MSPropertyAttr);
6411
6412	/// Diagnose why the specified class does not have a trivial special member of
6413	/// the given kind.
6414	void DiagnoseNontrivial(const CXXRecordDecl *Record,
6415	CXXSpecialMemberKind CSM);
6416
6417	/// Determine whether a defaulted or deleted special member function is
6418	/// trivial, as specified in C++11 [class.ctor]p5, C++11 [class.copy]p12,
6419	/// C++11 [class.copy]p25, and C++11 [class.dtor]p5.
6420	bool SpecialMemberIsTrivial(
6421	CXXMethodDecl *MD, CXXSpecialMemberKind CSM,
6422	TrivialABIHandling TAH = TrivialABIHandling::IgnoreTrivialABI,
6423	bool Diagnose = false);
6424
6425	/// For a defaulted function, the kind of defaulted function that it is.
6426	class DefaultedFunctionKind {
6427	LLVM_PREFERRED_TYPE(CXXSpecialMemberKind)
6428	unsigned SpecialMember : `8`;
6429	unsigned Comparison : `8`;
6430
6431	public:
6432	DefaultedFunctionKind()
6433	: SpecialMember(llvm::to_underlying(E: CXXSpecialMemberKind::Invalid)),
6434	Comparison(llvm::to_underlying(E: DefaultedComparisonKind::None)) {}
6435	DefaultedFunctionKind(CXXSpecialMemberKind CSM)
6436	: SpecialMember(llvm::to_underlying(E: CSM)),
6437	Comparison(llvm::to_underlying(E: DefaultedComparisonKind::None)) {}
6438	DefaultedFunctionKind(DefaultedComparisonKind Comp)
6439	: SpecialMember(llvm::to_underlying(E: CXXSpecialMemberKind::Invalid)),
6440	Comparison(llvm::to_underlying(E: Comp)) {}
6441
6442	bool isSpecialMember() const {
6443	return static_cast<CXXSpecialMemberKind>(SpecialMember) !=
6444	CXXSpecialMemberKind::Invalid;
6445	}
6446	bool isComparison() const {
6447	return static_cast<DefaultedComparisonKind>(Comparison) !=
6448	DefaultedComparisonKind::None;
6449	}
6450
6451	explicit operator bool() const {
6452	return isSpecialMember() \|\| isComparison();
6453	}
6454
6455	CXXSpecialMemberKind asSpecialMember() const {
6456	return static_cast<CXXSpecialMemberKind>(SpecialMember);
6457	}
6458	DefaultedComparisonKind asComparison() const {
6459	return static_cast<DefaultedComparisonKind>(Comparison);
6460	}
6461
6462	/// Get the index of this function kind for use in diagnostics.
6463	unsigned getDiagnosticIndex() const {
6464	static_assert(llvm::to_underlying(E: CXXSpecialMemberKind::Invalid) >
6465	llvm::to_underlying(E: CXXSpecialMemberKind::Destructor),
6466	"invalid should have highest index");
6467	static_assert((unsigned)DefaultedComparisonKind::None == `0`,
6468	"none should be equal to zero");
6469	return SpecialMember + Comparison;
6470	}
6471	};
6472
6473	/// Determine the kind of defaulting that would be done for a given function.
6474	///
6475	/// If the function is both a default constructor and a copy / move
6476	/// constructor (due to having a default argument for the first parameter),
6477	/// this picks CXXSpecialMemberKind::DefaultConstructor.
6478	///
6479	/// FIXME: Check that case is properly handled by all callers.
6480	DefaultedFunctionKind getDefaultedFunctionKind(const FunctionDecl *FD);
6481
6482	/// Handle a C++11 empty-declaration and attribute-declaration.
6483	Decl ActOnEmptyDeclaration(Scope S, const ParsedAttributesView &AttrList,
6484	SourceLocation SemiLoc);
6485
6486	enum class CheckConstexprKind {
6487	/// Diagnose issues that are non-constant or that are extensions.
6488	Diagnose,
6489	/// Identify whether this function satisfies the formal rules for constexpr
6490	/// functions in the current lanugage mode (with no extensions).
6491	CheckValid
6492	};
6493
6494	// Check whether a function declaration satisfies the requirements of a
6495	// constexpr function definition or a constexpr constructor definition. If so,
6496	// return true. If not, produce appropriate diagnostics (unless asked not to
6497	// by Kind) and return false.
6498	//
6499	// This implements C++11 [dcl.constexpr]p3,4, as amended by DR1360.
6500	bool CheckConstexprFunctionDefinition(const FunctionDecl *FD,
6501	CheckConstexprKind Kind);
6502
6503	/// Diagnose methods which overload virtual methods in a base class
6504	/// without overriding any.
6505	void DiagnoseHiddenVirtualMethods(CXXMethodDecl *MD);
6506
6507	/// Check if a method overloads virtual methods in a base class without
6508	/// overriding any.
6509	void
6510	FindHiddenVirtualMethods(CXXMethodDecl *MD,
6511	SmallVectorImpl<CXXMethodDecl *> &OverloadedMethods);
6512	void
6513	NoteHiddenVirtualMethods(CXXMethodDecl *MD,
6514	SmallVectorImpl<CXXMethodDecl *> &OverloadedMethods);
6515
6516	/// ActOnParamDefaultArgument - Check whether the default argument
6517	/// provided for a function parameter is well-formed. If so, attach it
6518	/// to the parameter declaration.
6519	void ActOnParamDefaultArgument(Decl *param, SourceLocation EqualLoc,
6520	Expr *defarg);
6521
6522	/// ActOnParamUnparsedDefaultArgument - We've seen a default
6523	/// argument for a function parameter, but we can't parse it yet
6524	/// because we're inside a class definition. Note that this default
6525	/// argument will be parsed later.
6526	void ActOnParamUnparsedDefaultArgument(Decl *param, SourceLocation EqualLoc,
6527	SourceLocation ArgLoc);
6528
6529	/// ActOnParamDefaultArgumentError - Parsing or semantic analysis of
6530	/// the default argument for the parameter param failed.
6531	void ActOnParamDefaultArgumentError(Decl *param, SourceLocation EqualLoc,
6532	Expr *DefaultArg);
6533	ExprResult ConvertParamDefaultArgument(ParmVarDecl Param, Expr DefaultArg,
6534	SourceLocation EqualLoc);
6535	void SetParamDefaultArgument(ParmVarDecl Param, Expr DefaultArg,
6536	SourceLocation EqualLoc);
6537
6538	void ActOnPureSpecifier(Decl *D, SourceLocation PureSpecLoc);
6539	void SetDeclDeleted(Decl *dcl, SourceLocation DelLoc,
6540	StringLiteral Message = nullptr*);
6541	void SetDeclDefaulted(Decl *dcl, SourceLocation DefaultLoc);
6542
6543	void SetFunctionBodyKind(Decl *D, SourceLocation Loc, FnBodyKind BodyKind,
6544	StringLiteral DeletedMessage = nullptr*);
6545	void ActOnStartTrailingRequiresClause(Scope *S, Declarator &D);
6546	ExprResult ActOnFinishTrailingRequiresClause(ExprResult ConstraintExpr);
6547	ExprResult ActOnRequiresClause(ExprResult ConstraintExpr);
6548
6549	NamedDecl *
6550	ActOnDecompositionDeclarator(Scope *S, Declarator &D,
6551	MultiTemplateParamsArg TemplateParamLists);
6552	void DiagPlaceholderVariableDefinition(SourceLocation Loc);
6553	bool DiagRedefinedPlaceholderFieldDecl(SourceLocation Loc,
6554	RecordDecl *ClassDecl,
6555	const IdentifierInfo *Name);
6556
6557	UnsignedOrNone GetDecompositionElementCount(QualType DecompType,
6558	SourceLocation Loc);
6559	void CheckCompleteDecompositionDeclaration(DecompositionDecl *DD);
6560
6561	/// Stack containing information needed when in C++2a an 'auto' is encountered
6562	/// in a function declaration parameter type specifier in order to invent a
6563	/// corresponding template parameter in the enclosing abbreviated function
6564	/// template. This information is also present in LambdaScopeInfo, stored in
6565	/// the FunctionScopes stack.
6566	SmallVector<InventedTemplateParameterInfo, `4`> InventedParameterInfos;
6567
6568	/// FieldCollector - Collects CXXFieldDecls during parsing of C++ classes.
6569	std::unique_ptr<CXXFieldCollector> FieldCollector;
6570
6571	typedef llvm::SmallSetVector<const NamedDecl *, `16`> NamedDeclSetType;
6572	/// Set containing all declared private fields that are not used.
6573	NamedDeclSetType UnusedPrivateFields;
6574
6575	typedef llvm::SmallPtrSet<const CXXRecordDecl *, `8`> RecordDeclSetTy;
6576
6577	/// PureVirtualClassDiagSet - a set of class declarations which we have
6578	/// emitted a list of pure virtual functions. Used to prevent emitting the
6579	/// same list more than once.
6580	std::unique_ptr<RecordDeclSetTy> PureVirtualClassDiagSet;
6581
6582	typedef LazyVector<CXXConstructorDecl *, ExternalSemaSource,
6583	&ExternalSemaSource::ReadDelegatingConstructors, `2`, `2`>
6584	DelegatingCtorDeclsType;
6585
6586	/// All the delegating constructors seen so far in the file, used for
6587	/// cycle detection at the end of the TU.
6588	DelegatingCtorDeclsType DelegatingCtorDecls;
6589
6590	/// The C++ "std" namespace, where the standard library resides.
6591	LazyDeclPtr StdNamespace;
6592
6593	/// The C++ "std::initializer_list" template, which is defined in
6594	/// \<initializer_list>.
6595	ClassTemplateDecl *StdInitializerList;
6596
6597	/// The C++ "std::type_identity" template, which is defined in
6598	/// \<type_traits>.
6599	ClassTemplateDecl *StdTypeIdentity;
6600
6601	// Contains the locations of the beginning of unparsed default
6602	// argument locations.
6603	llvm::DenseMap<ParmVarDecl *, SourceLocation> UnparsedDefaultArgLocs;
6604
6605	/// UndefinedInternals - all the used, undefined objects which require a
6606	/// definition in this translation unit.
6607	llvm::MapVector<NamedDecl *, SourceLocation> UndefinedButUsed;
6608
6609	typedef llvm::PointerIntPair<CXXRecordDecl *, `3`, CXXSpecialMemberKind>
6610	SpecialMemberDecl;
6611
6612	/// The C++ special members which we are currently in the process of
6613	/// declaring. If this process recursively triggers the declaration of the
6614	/// same special member, we should act as if it is not yet declared.
6615	llvm::SmallPtrSet<SpecialMemberDecl, `4`> SpecialMembersBeingDeclared;
6616
6617	void NoteDeletedInheritingConstructor(CXXConstructorDecl *CD);
6618
6619	void ActOnDefaultCtorInitializers(Decl *CDtorDecl);
6620
6621	typedef ProcessingContextState ParsingClassState;
6622	ParsingClassState PushParsingClass() {
6623	ParsingClassDepth++;
6624	return DelayedDiagnostics.pushUndelayed();
6625	}
6626	void PopParsingClass(ParsingClassState state) {
6627	ParsingClassDepth--;
6628	DelayedDiagnostics.popUndelayed(state);
6629	}
6630
6631	ValueDecl tryLookupCtorInitMemberDecl(CXXRecordDecl ClassDecl,
6632	CXXScopeSpec &SS,
6633	ParsedType TemplateTypeTy,
6634	IdentifierInfo *MemberOrBase);
6635
6636	private:
6637	void setupImplicitSpecialMemberType(CXXMethodDecl *SpecialMem,
6638	QualType ResultTy,
6639	ArrayRef<QualType> Args);
6640	// Helper for ActOnFields to check for all function pointer members.
6641	bool EntirelyFunctionPointers(const RecordDecl *Record);
6642
6643	// A cache representing if we've fully checked the various comparison category
6644	// types stored in ASTContext. The bit-index corresponds to the integer value
6645	// of a ComparisonCategoryType enumerator.
6646	llvm::SmallBitVector FullyCheckedComparisonCategories;
6647
6648	/// Check if there is a field shadowing.
6649	void CheckShadowInheritedFields(const SourceLocation &Loc,
6650	DeclarationName FieldName,
6651	const CXXRecordDecl *RD,
6652	bool DeclIsField = true);
6653
6654	///@}
6655
6656	//
6657	//
6658	// -------------------------------------------------------------------------
6659	//
6660	//
6661
6662	/// \name C++ Exception Specifications
6663	/// Implementations are in SemaExceptionSpec.cpp
6664	///@{
6665
6666	public:
6667	/// All the overriding functions seen during a class definition
6668	/// that had their exception spec checks delayed, plus the overridden
6669	/// function.
6670	SmallVector<std::pair<const CXXMethodDecl , const* CXXMethodDecl *>, `2`>
6671	DelayedOverridingExceptionSpecChecks;
6672
6673	/// All the function redeclarations seen during a class definition that had
6674	/// their exception spec checks delayed, plus the prior declaration they
6675	/// should be checked against. Except during error recovery, the new decl
6676	/// should always be a friend declaration, as that's the only valid way to
6677	/// redeclare a special member before its class is complete.
6678	SmallVector<std::pair<FunctionDecl , FunctionDecl >, `2`>
6679	DelayedEquivalentExceptionSpecChecks;
6680
6681	/// Determine if we're in a case where we need to (incorrectly) eagerly
6682	/// parse an exception specification to work around a libstdc++ bug.
6683	bool isLibstdcxxEagerExceptionSpecHack(const Declarator &D);
6684
6685	/// Check the given noexcept-specifier, convert its expression, and compute
6686	/// the appropriate ExceptionSpecificationType.
6687	ExprResult ActOnNoexceptSpec(Expr *NoexceptExpr,
6688	ExceptionSpecificationType &EST);
6689
6690	CanThrowResult canThrow(const Stmt *E);
6691	/// Determine whether the callee of a particular function call can throw.
6692	/// E, D and Loc are all optional.
6693	static CanThrowResult canCalleeThrow(Sema &S, const Expr E, const* Decl *D,
6694	SourceLocation Loc = SourceLocation ());
6695	const FunctionProtoType *ResolveExceptionSpec(SourceLocation Loc,
6696	const FunctionProtoType *FPT);
6697	void UpdateExceptionSpec(FunctionDecl *FD,
6698	const FunctionProtoType::ExceptionSpecInfo &ESI);
6699
6700	/// CheckSpecifiedExceptionType - Check if the given type is valid in an
6701	/// exception specification. Incomplete types, or pointers to incomplete types
6702	/// other than void are not allowed.
6703	///
6704	/// \param[in,out] T The exception type. This will be decayed to a pointer
6705	/// type
6706	/// when the input is an array or a function type.
6707	bool CheckSpecifiedExceptionType(QualType &T, SourceRange Range);
6708
6709	/// CheckDistantExceptionSpec - Check if the given type is a pointer or
6710	/// pointer to member to a function with an exception specification. This
6711	/// means that it is invalid to add another level of indirection.
6712	bool CheckDistantExceptionSpec(QualType T);
6713	bool CheckEquivalentExceptionSpec(FunctionDecl Old, FunctionDecl New);
6714
6715	/// CheckEquivalentExceptionSpec - Check if the two types have equivalent
6716	/// exception specifications. Exception specifications are equivalent if
6717	/// they allow exactly the same set of exception types. It does not matter how
6718	/// that is achieved. See C++ [except.spec]p2.
6719	bool CheckEquivalentExceptionSpec(const FunctionProtoType *Old,
6720	SourceLocation OldLoc,
6721	const FunctionProtoType *New,
6722	SourceLocation NewLoc);
6723	bool CheckEquivalentExceptionSpec(const PartialDiagnostic &DiagID,
6724	const PartialDiagnostic &NoteID,
6725	const FunctionProtoType *Old,
6726	SourceLocation OldLoc,
6727	const FunctionProtoType *New,
6728	SourceLocation NewLoc);
6729	bool handlerCanCatch(QualType HandlerType, QualType ExceptionType);
6730
6731	/// CheckExceptionSpecSubset - Check whether the second function type's
6732	/// exception specification is a subset (or equivalent) of the first function
6733	/// type. This is used by override and pointer assignment checks.
6734	bool CheckExceptionSpecSubset(
6735	const PartialDiagnostic &DiagID, const PartialDiagnostic &NestedDiagID,
6736	const PartialDiagnostic &NoteID, const PartialDiagnostic &NoThrowDiagID,
6737	const FunctionProtoType Superset, bool* SkipSupersetFirstParameter,
6738	SourceLocation SuperLoc, const FunctionProtoType *Subset,
6739	bool SkipSubsetFirstParameter, SourceLocation SubLoc);
6740
6741	/// CheckParamExceptionSpec - Check if the parameter and return types of the
6742	/// two functions have equivalent exception specs. This is part of the
6743	/// assignment and override compatibility check. We do not check the
6744	/// parameters of parameter function pointers recursively, as no sane
6745	/// programmer would even be able to write such a function type.
6746	bool CheckParamExceptionSpec(
6747	const PartialDiagnostic &NestedDiagID, const PartialDiagnostic &NoteID,
6748	const FunctionProtoType Target, bool* SkipTargetFirstParameter,
6749	SourceLocation TargetLoc, const FunctionProtoType *Source,
6750	bool SkipSourceFirstParameter, SourceLocation SourceLoc);
6751
6752	bool CheckExceptionSpecCompatibility(Expr *From, QualType ToType);
6753
6754	/// CheckOverridingFunctionExceptionSpec - Checks whether the exception
6755	/// spec is a subset of base spec.
6756	bool CheckOverridingFunctionExceptionSpec(const CXXMethodDecl *New,
6757	const CXXMethodDecl *Old);
6758
6759	///@}
6760
6761	//
6762	//
6763	// -------------------------------------------------------------------------
6764	//
6765	//
6766
6767	/// \name Expressions
6768	/// Implementations are in SemaExpr.cpp
6769	///@{
6770
6771	public:
6772	/// Describes how the expressions currently being parsed are
6773	/// evaluated at run-time, if at all.
6774	enum class ExpressionEvaluationContext {
6775	/// The current expression and its subexpressions occur within an
6776	/// unevaluated operand (C++11 [expr]p7), such as the subexpression of
6777	/// \c sizeof, where the type of the expression may be significant but
6778	/// no code will be generated to evaluate the value of the expression at
6779	/// run time.
6780	Unevaluated,
6781
6782	/// The current expression occurs within a braced-init-list within
6783	/// an unevaluated operand. This is mostly like a regular unevaluated
6784	/// context, except that we still instantiate constexpr functions that are
6785	/// referenced here so that we can perform narrowing checks correctly.
6786	UnevaluatedList,
6787
6788	/// The current expression occurs within a discarded statement.
6789	/// This behaves largely similarly to an unevaluated operand in preventing
6790	/// definitions from being required, but not in other ways.
6791	DiscardedStatement,
6792
6793	/// The current expression occurs within an unevaluated
6794	/// operand that unconditionally permits abstract references to
6795	/// fields, such as a SIZE operator in MS-style inline assembly.
6796	UnevaluatedAbstract,
6797
6798	/// The current context is "potentially evaluated" in C++11 terms,
6799	/// but the expression is evaluated at compile-time (like the values of
6800	/// cases in a switch statement).
6801	ConstantEvaluated,
6802
6803	/// In addition of being constant evaluated, the current expression
6804	/// occurs in an immediate function context - either a consteval function
6805	/// or a consteval if statement.
6806	ImmediateFunctionContext,
6807
6808	/// The current expression is potentially evaluated at run time,
6809	/// which means that code may be generated to evaluate the value of the
6810	/// expression at run time.
6811	PotentiallyEvaluated,
6812
6813	/// The current expression is potentially evaluated, but any
6814	/// declarations referenced inside that expression are only used if
6815	/// in fact the current expression is used.
6816	///
6817	/// This value is used when parsing default function arguments, for which
6818	/// we would like to provide diagnostics (e.g., passing non-POD arguments
6819	/// through varargs) but do not want to mark declarations as "referenced"
6820	/// until the default argument is used.
6821	PotentiallyEvaluatedIfUsed
6822	};
6823
6824	/// Store a set of either DeclRefExprs or MemberExprs that contain a reference
6825	/// to a variable (constant) that may or may not be odr-used in this Expr, and
6826	/// we won't know until all lvalue-to-rvalue and discarded value conversions
6827	/// have been applied to all subexpressions of the enclosing full expression.
6828	/// This is cleared at the end of each full expression.
6829	using MaybeODRUseExprSet = llvm::SmallSetVector<Expr *, `4`>;
6830	MaybeODRUseExprSet MaybeODRUseExprs;
6831
6832	using ImmediateInvocationCandidate = llvm::PointerIntPair<ConstantExpr *, `1`>;
6833
6834	/// Data structure used to record current or nested
6835	/// expression evaluation contexts.
6836	struct ExpressionEvaluationContextRecord {
6837	/// The expression evaluation context.
6838	ExpressionEvaluationContext Context;
6839
6840	/// Whether the enclosing context needed a cleanup.
6841	CleanupInfo ParentCleanup;
6842
6843	/// The number of active cleanup objects when we entered
6844	/// this expression evaluation context.
6845	unsigned NumCleanupObjects;
6846
6847	MaybeODRUseExprSet SavedMaybeODRUseExprs;
6848
6849	/// The lambdas that are present within this context, if it
6850	/// is indeed an unevaluated context.
6851	SmallVector<LambdaExpr *, `2`> Lambdas;
6852
6853	/// The declaration that provides context for lambda expressions
6854	/// and block literals if the normal declaration context does not
6855	/// suffice, e.g., in a default function argument.
6856	Decl *ManglingContextDecl;
6857
6858	/// Declaration for initializer if one is currently being
6859	/// parsed. Used when an expression has a possibly unreachable
6860	/// diagnostic to reference the declaration as a whole.
6861	VarDecl DeclForInitializer = nullptr*;
6862
6863	/// If we are processing a decltype type, a set of call expressions
6864	/// for which we have deferred checking the completeness of the return type.
6865	SmallVector<CallExpr *, `8`> DelayedDecltypeCalls;
6866
6867	/// If we are processing a decltype type, a set of temporary binding
6868	/// expressions for which we have deferred checking the destructor.
6869	SmallVector<CXXBindTemporaryExpr *, `8`> DelayedDecltypeBinds;
6870
6871	llvm::SmallPtrSet<const Expr *, `8`> PossibleDerefs;
6872
6873	/// Expressions appearing as the LHS of a volatile assignment in this
6874	/// context. We produce a warning for these when popping the context if
6875	/// they are not discarded-value expressions nor unevaluated operands.
6876	SmallVector<Expr *, `2`> VolatileAssignmentLHSs;
6877
6878	/// Set of candidates for starting an immediate invocation.
6879	llvm::SmallVector<ImmediateInvocationCandidate, `4`>
6880	ImmediateInvocationCandidates;
6881
6882	/// Set of DeclRefExprs referencing a consteval function when used in a
6883	/// context not already known to be immediately invoked.
6884	llvm::SmallPtrSet<DeclRefExpr *, `4`> ReferenceToConsteval;
6885
6886	/// P2718R0 - Lifetime extension in range-based for loops.
6887	/// MaterializeTemporaryExprs in for-range-init expressions which need to
6888	/// extend lifetime. Add MaterializeTemporaryExpr if the value of*
6889	/// InLifetimeExtendingContext is true.
6890	SmallVector<MaterializeTemporaryExpr *, `8`> ForRangeLifetimeExtendTemps;
6891
6892	/// Small set of gathered accesses to potentially misaligned members
6893	/// due to the packed attribute.
6894	SmallVector<MisalignedMember, `4`> MisalignedMembers;
6895
6896	/// \brief Describes whether we are in an expression constext which we have
6897	/// to handle differently.
6898	enum ExpressionKind {
6899	EK_Decltype,
6900	EK_TemplateArgument,
6901	EK_AttrArgument,
6902	EK_VariableInit,
6903	EK_Other
6904	} ExprContext;
6905
6906	// A context can be nested in both a discarded statement context and
6907	// an immediate function context, so they need to be tracked independently.
6908	bool InDiscardedStatement;
6909	bool InImmediateFunctionContext;
6910	bool InImmediateEscalatingFunctionContext;
6911
6912	bool IsCurrentlyCheckingDefaultArgumentOrInitializer = false;
6913
6914	// We are in a constant context, but we also allow
6915	// non constant expressions, for example for array bounds (which may be
6916	// VLAs).
6917	bool InConditionallyConstantEvaluateContext = false;
6918
6919	/// Whether we are currently in a context in which all temporaries must be
6920	/// lifetime-extended, even if they're not bound to a reference (for
6921	/// example, in a for-range initializer).
6922	bool InLifetimeExtendingContext = false;
6923
6924	/// Whether evaluating an expression for a switch case label.
6925	bool IsCaseExpr = false;
6926
6927	/// Whether we should rebuild CXXDefaultArgExpr and CXXDefaultInitExpr.
6928	bool RebuildDefaultArgOrDefaultInit = false;
6929
6930	// When evaluating immediate functions in the initializer of a default
6931	// argument or default member initializer, this is the declaration whose
6932	// default initializer is being evaluated and the location of the call
6933	// or constructor definition.
6934	struct InitializationContext {
6935	InitializationContext(SourceLocation Loc, ValueDecl *Decl,
6936	DeclContext *Context)
6937	: Loc (Loc), Decl(Decl), Context(Context) {
6938	assert(Decl && Context && "invalid initialization context");
6939	}
6940
6941	SourceLocation Loc;
6942	ValueDecl Decl = nullptr*;
6943	DeclContext Context = nullptr*;
6944	};
6945	std::optional<InitializationContext> DelayedDefaultInitializationContext;
6946
6947	ExpressionEvaluationContextRecord(ExpressionEvaluationContext Context,
6948	unsigned NumCleanupObjects,
6949	CleanupInfo ParentCleanup,
6950	Decl *ManglingContextDecl,
6951	ExpressionKind ExprContext)
6952	: Context(Context), ParentCleanup (ParentCleanup),
6953	NumCleanupObjects(NumCleanupObjects),
6954	ManglingContextDecl(ManglingContextDecl), ExprContext(ExprContext),
6955	InDiscardedStatement(false), InImmediateFunctionContext(false),
6956	InImmediateEscalatingFunctionContext(false) {}
6957
6958	bool isUnevaluated() const {
6959	return Context == ExpressionEvaluationContext::Unevaluated \|\|
6960	Context == ExpressionEvaluationContext::UnevaluatedAbstract \|\|
6961	Context == ExpressionEvaluationContext::UnevaluatedList;
6962	}
6963
6964	bool isPotentiallyEvaluated() const {
6965	return Context == ExpressionEvaluationContext::PotentiallyEvaluated \|\|
6966	Context ==
6967	ExpressionEvaluationContext::PotentiallyEvaluatedIfUsed \|\|
6968	Context == ExpressionEvaluationContext::ConstantEvaluated;
6969	}
6970
6971	bool isConstantEvaluated() const {
6972	return Context == ExpressionEvaluationContext::ConstantEvaluated \|\|
6973	Context == ExpressionEvaluationContext::ImmediateFunctionContext;
6974	}
6975
6976	bool isImmediateFunctionContext() const {
6977	return Context == ExpressionEvaluationContext::ImmediateFunctionContext \|\|
6978	(Context == ExpressionEvaluationContext::DiscardedStatement &&
6979	InImmediateFunctionContext) \|\|
6980	// C++23 [expr.const]p14:
6981	// An expression or conversion is in an immediate function
6982	// context if it is potentially evaluated and either:
6983	// its innermost enclosing non-block scope is a function*
6984	// parameter scope of an immediate function, or
6985	// its enclosing statement is enclosed by the compound-*
6986	// statement of a consteval if statement.
6987	(Context == ExpressionEvaluationContext::PotentiallyEvaluated &&
6988	InImmediateFunctionContext);
6989	}
6990
6991	bool isDiscardedStatementContext() const {
6992	return Context == ExpressionEvaluationContext::DiscardedStatement \|\|
6993	((Context ==
6994	ExpressionEvaluationContext::ImmediateFunctionContext \|\|
6995	isPotentiallyEvaluated()) &&
6996	InDiscardedStatement);
6997	}
6998	};
6999
7000	const ExpressionEvaluationContextRecord &currentEvaluationContext() const {
7001	assert(!ExprEvalContexts.empty() &&
7002	"Must be in an expression evaluation context");
7003	return ExprEvalContexts.back();
7004	}
7005
7006	ExpressionEvaluationContextRecord &currentEvaluationContext() {
7007	assert(!ExprEvalContexts.empty() &&
7008	"Must be in an expression evaluation context");
7009	return ExprEvalContexts.back();
7010	}
7011
7012	ExpressionEvaluationContextRecord &parentEvaluationContext() {
7013	assert(ExprEvalContexts.size() >= `2` &&
7014	"Must be in an expression evaluation context");
7015	return ExprEvalContexts [ExprEvalContexts.size() - `2`];
7016	}
7017
7018	const ExpressionEvaluationContextRecord &parentEvaluationContext() const {
7019	return const_cast<Sema >(this*)->parentEvaluationContext();
7020	}
7021
7022	bool isAttrContext() const {
7023	return ExprEvalContexts.back().ExprContext ==
7024	ExpressionEvaluationContextRecord::ExpressionKind::EK_AttrArgument;
7025	}
7026
7027	/// Increment when we find a reference; decrement when we find an ignored
7028	/// assignment. Ultimately the value is 0 if every reference is an ignored
7029	/// assignment.
7030	///
7031	/// Uses canonical VarDecl as key so in-class decls and out-of-class defs of
7032	/// static data members get tracked as a single entry.
7033	llvm::DenseMap<const VarDecl , int*> RefsMinusAssignments;
7034
7035	/// Used to control the generation of ExprWithCleanups.
7036	CleanupInfo Cleanup;
7037
7038	/// ExprCleanupObjects - This is the stack of objects requiring
7039	/// cleanup that are created by the current full expression.
7040	SmallVector<ExprWithCleanups::CleanupObject, `8`> ExprCleanupObjects;
7041
7042	/// Determine whether the use of this declaration is valid, without
7043	/// emitting diagnostics.
7044	bool CanUseDecl(NamedDecl D, bool* TreatUnavailableAsInvalid);
7045	// A version of DiagnoseUseOfDecl that should be used if overload resolution
7046	// has been used to find this declaration, which means we don't have to bother
7047	// checking the trailing requires clause.
7048	bool DiagnoseUseOfOverloadedDecl(NamedDecl *D, SourceLocation Loc) {
7049	return DiagnoseUseOfDecl(
7050	D, Locs: Loc, /UnknownObjCClass=/UnknownObjCClass: nullptr, /ObjCPropertyAccess=/ObjCPropertyAccess: false,
7051	/AvoidPartialAvailabilityChecks=/AvoidPartialAvailabilityChecks: false, /ClassReceiver=/ClassReceiver: nullptr,
7052	/SkipTrailingRequiresClause=/SkipTrailingRequiresClause: true);
7053	}
7054
7055	/// Determine whether the use of this declaration is valid, and
7056	/// emit any corresponding diagnostics.
7057	///
7058	/// This routine diagnoses various problems with referencing
7059	/// declarations that can occur when using a declaration. For example,
7060	/// it might warn if a deprecated or unavailable declaration is being
7061	/// used, or produce an error (and return true) if a C++0x deleted
7062	/// function is being used.
7063	///
7064	/// \returns true if there was an error (this declaration cannot be
7065	/// referenced), false otherwise.
7066	bool DiagnoseUseOfDecl(NamedDecl *D, ArrayRef<SourceLocation> Locs,
7067	const ObjCInterfaceDecl UnknownObjCClass = nullptr*,
7068	bool ObjCPropertyAccess = false,
7069	bool AvoidPartialAvailabilityChecks = false,
7070	ObjCInterfaceDecl ClassReceiver = nullptr*,
7071	bool SkipTrailingRequiresClause = false);
7072
7073	/// Emit a note explaining that this function is deleted.
7074	void NoteDeletedFunction(FunctionDecl *FD);
7075
7076	/// DiagnoseSentinelCalls - This routine checks whether a call or
7077	/// message-send is to a declaration with the sentinel attribute, and
7078	/// if so, it checks that the requirements of the sentinel are
7079	/// satisfied.
7080	void DiagnoseSentinelCalls(const NamedDecl *D, SourceLocation Loc,
7081	ArrayRef<Expr *> Args);
7082
7083	void PushExpressionEvaluationContext(
7084	ExpressionEvaluationContext NewContext, Decl LambdaContextDecl = nullptr*,
7085	ExpressionEvaluationContextRecord::ExpressionKind Type =
7086	ExpressionEvaluationContextRecord::EK_Other);
7087
7088	void PushExpressionEvaluationContextForFunction(
7089	ExpressionEvaluationContext NewContext, FunctionDecl *FD);
7090
7091	enum ReuseLambdaContextDecl_t { ReuseLambdaContextDecl };
7092	void PushExpressionEvaluationContext(
7093	ExpressionEvaluationContext NewContext, ReuseLambdaContextDecl_t,
7094	ExpressionEvaluationContextRecord::ExpressionKind Type =
7095	ExpressionEvaluationContextRecord::EK_Other);
7096	void PopExpressionEvaluationContext();
7097
7098	void DiscardCleanupsInEvaluationContext();
7099
7100	ExprResult TransformToPotentiallyEvaluated(Expr *E);
7101	TypeSourceInfo TransformToPotentiallyEvaluated(TypeSourceInfo TInfo);
7102	ExprResult HandleExprEvaluationContextForTypeof(Expr *E);
7103
7104	/// Check whether E, which is either a discarded-value expression or an
7105	/// unevaluated operand, is a simple-assignment to a volatlie-qualified
7106	/// lvalue, and if so, remove it from the list of volatile-qualified
7107	/// assignments that we are going to warn are deprecated.
7108	void CheckUnusedVolatileAssignment(Expr *E);
7109
7110	ExprResult ActOnConstantExpression(ExprResult Res);
7111
7112	// Functions for marking a declaration referenced. These functions also
7113	// contain the relevant logic for marking if a reference to a function or
7114	// variable is an odr-use (in the C++11 sense). There are separate variants
7115	// for expressions referring to a decl; these exist because odr-use marking
7116	// needs to be delayed for some constant variables when we build one of the
7117	// named expressions.
7118	//
7119	// MightBeOdrUse indicates whether the use could possibly be an odr-use, and
7120	// should usually be true. This only needs to be set to false if the lack of
7121	// odr-use cannot be determined from the current context (for instance,
7122	// because the name denotes a virtual function and was written without an
7123	// explicit nested-name-specifier).
7124	void MarkAnyDeclReferenced(SourceLocation Loc, Decl D, bool* MightBeOdrUse);
7125
7126	/// Mark a function referenced, and check whether it is odr-used
7127	/// (C++ [basic.def.odr]p2, C99 6.9p3)
7128	void MarkFunctionReferenced(SourceLocation Loc, FunctionDecl *Func,
7129	bool MightBeOdrUse = true);
7130
7131	/// Mark a variable referenced, and check whether it is odr-used
7132	/// (C++ [basic.def.odr]p2, C99 6.9p3). Note that this should not be
7133	/// used directly for normal expressions referring to VarDecl.
7134	void MarkVariableReferenced(SourceLocation Loc, VarDecl *Var);
7135
7136	/// Perform reference-marking and odr-use handling for a DeclRefExpr.
7137	///
7138	/// Note, this may change the dependence of the DeclRefExpr, and so needs to
7139	/// be handled with care if the DeclRefExpr is not newly-created.
7140	void MarkDeclRefReferenced(DeclRefExpr E, const* Expr Base = nullptr*);
7141
7142	/// Perform reference-marking and odr-use handling for a MemberExpr.
7143	void MarkMemberReferenced(MemberExpr *E);
7144
7145	/// Perform reference-marking and odr-use handling for a FunctionParmPackExpr.
7146	void MarkFunctionParmPackReferenced(FunctionParmPackExpr *E);
7147	void MarkCaptureUsedInEnclosingContext(ValueDecl *Capture, SourceLocation Loc,
7148	unsigned CapturingScopeIndex);
7149
7150	ExprResult CheckLValueToRValueConversionOperand(Expr *E);
7151	void CleanupVarDeclMarking();
7152
7153	/// Try to capture the given variable.
7154	///
7155	/// \param Var The variable to capture.
7156	///
7157	/// \param Loc The location at which the capture occurs.
7158	///
7159	/// \param Kind The kind of capture, which may be implicit (for either a
7160	/// block or a lambda), or explicit by-value or by-reference (for a lambda).
7161	///
7162	/// \param EllipsisLoc The location of the ellipsis, if one is provided in
7163	/// an explicit lambda capture.
7164	///
7165	/// \param BuildAndDiagnose Whether we are actually supposed to add the
7166	/// captures or diagnose errors. If false, this routine merely check whether
7167	/// the capture can occur without performing the capture itself or complaining
7168	/// if the variable cannot be captured.
7169	///
7170	/// \param CaptureType Will be set to the type of the field used to capture
7171	/// this variable in the innermost block or lambda. Only valid when the
7172	/// variable can be captured.
7173	///
7174	/// \param DeclRefType Will be set to the type of a reference to the capture
7175	/// from within the current scope. Only valid when the variable can be
7176	/// captured.
7177	///
7178	/// \param FunctionScopeIndexToStopAt If non-null, it points to the index
7179	/// of the FunctionScopeInfo stack beyond which we do not attempt to capture.
7180	/// This is useful when enclosing lambdas must speculatively capture
7181	/// variables that may or may not be used in certain specializations of
7182	/// a nested generic lambda.
7183	///
7184	/// \returns true if an error occurred (i.e., the variable cannot be
7185	/// captured) and false if the capture succeeded.
7186	bool tryCaptureVariable(ValueDecl *Var, SourceLocation Loc,
7187	TryCaptureKind Kind, SourceLocation EllipsisLoc,
7188	bool BuildAndDiagnose, QualType &CaptureType,
7189	QualType &DeclRefType,
7190	const unsigned *const FunctionScopeIndexToStopAt);
7191
7192	/// Try to capture the given variable.
7193	bool tryCaptureVariable(ValueDecl *Var, SourceLocation Loc,
7194	TryCaptureKind Kind = TryCaptureKind::Implicit,
7195	SourceLocation EllipsisLoc = SourceLocation ());
7196
7197	/// Checks if the variable must be captured.
7198	bool NeedToCaptureVariable(ValueDecl *Var, SourceLocation Loc);
7199
7200	/// Given a variable, determine the type that a reference to that
7201	/// variable will have in the given scope.
7202	QualType getCapturedDeclRefType(ValueDecl *Var, SourceLocation Loc);
7203
7204	/// Mark all of the declarations referenced within a particular AST node as
7205	/// referenced. Used when template instantiation instantiates a non-dependent
7206	/// type -- entities referenced by the type are now referenced.
7207	void MarkDeclarationsReferencedInType(SourceLocation Loc, QualType T);
7208
7209	/// Mark any declarations that appear within this expression or any
7210	/// potentially-evaluated subexpressions as "referenced".
7211	///
7212	/// \param SkipLocalVariables If true, don't mark local variables as
7213	/// 'referenced'.
7214	/// \param StopAt Subexpressions that we shouldn't recurse into.
7215	void MarkDeclarationsReferencedInExpr(Expr *E,
7216	bool SkipLocalVariables = false,
7217	ArrayRef<const Expr *> StopAt = {});
7218
7219	/// Try to convert an expression \p E to type \p Ty. Returns the result of the
7220	/// conversion.
7221	ExprResult tryConvertExprToType(Expr *E, QualType Ty);
7222
7223	/// Conditionally issue a diagnostic based on the statements's reachability
7224	/// analysis.
7225	///
7226	/// \param Stmts If Stmts is non-empty, delay reporting the diagnostic until
7227	/// the function body is parsed, and then do a basic reachability analysis to
7228	/// determine if the statement is reachable. If it is unreachable, the
7229	/// diagnostic will not be emitted.
7230	bool DiagIfReachable(SourceLocation Loc, ArrayRef<const Stmt *> Stmts,
7231	const PartialDiagnostic &PD);
7232
7233	/// Conditionally issue a diagnostic based on the current
7234	/// evaluation context.
7235	///
7236	/// \param Statement If Statement is non-null, delay reporting the
7237	/// diagnostic until the function body is parsed, and then do a basic
7238	/// reachability analysis to determine if the statement is reachable.
7239	/// If it is unreachable, the diagnostic will not be emitted.
7240	bool DiagRuntimeBehavior(SourceLocation Loc, const Stmt *Statement,
7241	const PartialDiagnostic &PD);
7242	/// Similar, but diagnostic is only produced if all the specified statements
7243	/// are reachable.
7244	bool DiagRuntimeBehavior(SourceLocation Loc, ArrayRef<const Stmt *> Stmts,
7245	const PartialDiagnostic &PD);
7246
7247	// Primary Expressions.
7248	SourceRange getExprRange(Expr E) const*;
7249
7250	ExprResult ActOnIdExpression(Scope *S, CXXScopeSpec &SS,
7251	SourceLocation TemplateKWLoc, UnqualifiedId &Id,
7252	bool HasTrailingLParen, bool IsAddressOfOperand,
7253	CorrectionCandidateCallback CCC = nullptr*,
7254	bool IsInlineAsmIdentifier = false,
7255	Token KeywordReplacement = nullptr*);
7256
7257	/// Decomposes the given name into a DeclarationNameInfo, its location, and
7258	/// possibly a list of template arguments.
7259	///
7260	/// If this produces template arguments, it is permitted to call
7261	/// DecomposeTemplateName.
7262	///
7263	/// This actually loses a lot of source location information for
7264	/// non-standard name kinds; we should consider preserving that in
7265	/// some way.
7266	void DecomposeUnqualifiedId(const UnqualifiedId &Id,
7267	TemplateArgumentListInfo &Buffer,
7268	DeclarationNameInfo &NameInfo,
7269	const TemplateArgumentListInfo *&TemplateArgs);
7270
7271	/// Diagnose a lookup that found results in an enclosing class during error
7272	/// recovery. This usually indicates that the results were found in a
7273	/// dependent base class that could not be searched as part of a template
7274	/// definition. Always issues a diagnostic (though this may be only a warning
7275	/// in MS compatibility mode).
7276	///
7277	/// Return \c true if the error is unrecoverable, or \c false if the caller
7278	/// should attempt to recover using these lookup results.
7279	bool DiagnoseDependentMemberLookup(const LookupResult &R);
7280
7281	/// Diagnose an empty lookup.
7282	///
7283	/// \return false if new lookup candidates were found
7284	bool
7285	DiagnoseEmptyLookup(Scope *S, CXXScopeSpec &SS, LookupResult &R,
7286	CorrectionCandidateCallback &CCC,
7287	TemplateArgumentListInfo ExplicitTemplateArgs = nullptr*,
7288	ArrayRef<Expr *> Args = {},
7289	DeclContext LookupCtx = nullptr*);
7290
7291	/// If \p D cannot be odr-used in the current expression evaluation context,
7292	/// return a reason explaining why. Otherwise, return NOUR_None.
7293	NonOdrUseReason getNonOdrUseReasonInCurrentContext(ValueDecl *D);
7294
7295	DeclRefExpr BuildDeclRefExpr(ValueDecl D, QualType Ty, ExprValueKind VK,
7296	SourceLocation Loc,
7297	const CXXScopeSpec SS = nullptr*);
7298	DeclRefExpr *
7299	BuildDeclRefExpr(ValueDecl *D, QualType Ty, ExprValueKind VK,
7300	const DeclarationNameInfo &NameInfo,
7301	const CXXScopeSpec SS = nullptr*,
7302	NamedDecl FoundD = nullptr*,
7303	SourceLocation TemplateKWLoc = SourceLocation (),
7304	const TemplateArgumentListInfo TemplateArgs = nullptr*);
7305
7306	/// BuildDeclRefExpr - Build an expression that references a
7307	/// declaration that does not require a closure capture.
7308	DeclRefExpr *
7309	BuildDeclRefExpr(ValueDecl *D, QualType Ty, ExprValueKind VK,
7310	const DeclarationNameInfo &NameInfo,
7311	NestedNameSpecifierLoc NNS, NamedDecl FoundD = nullptr*,
7312	SourceLocation TemplateKWLoc = SourceLocation (),
7313	const TemplateArgumentListInfo TemplateArgs = nullptr*);
7314
7315	bool UseArgumentDependentLookup(const CXXScopeSpec &SS, const LookupResult &R,
7316	bool HasTrailingLParen);
7317
7318	/// BuildQualifiedDeclarationNameExpr - Build a C++ qualified
7319	/// declaration name, generally during template instantiation.
7320	/// There's a large number of things which don't need to be done along
7321	/// this path.
7322	ExprResult BuildQualifiedDeclarationNameExpr(
7323	CXXScopeSpec &SS, const DeclarationNameInfo &NameInfo,
7324	bool IsAddressOfOperand, TypeSourceInfo RecoveryTSI = nullptr**);
7325
7326	ExprResult BuildDeclarationNameExpr(const CXXScopeSpec &SS, LookupResult &R,
7327	bool NeedsADL,
7328	bool AcceptInvalidDecl = false);
7329
7330	/// Complete semantic analysis for a reference to the given declaration.
7331	ExprResult BuildDeclarationNameExpr(
7332	const CXXScopeSpec &SS, const DeclarationNameInfo &NameInfo, NamedDecl *D,
7333	NamedDecl FoundD = nullptr*,
7334	const TemplateArgumentListInfo TemplateArgs = nullptr*,
7335	bool AcceptInvalidDecl = false);
7336
7337	// ExpandFunctionLocalPredefinedMacros - Returns a new vector of Tokens,
7338	// where Tokens representing function local predefined macros (such as
7339	// __FUNCTION__) are replaced (expanded) with string-literal Tokens.
7340	std::vector<Token> ExpandFunctionLocalPredefinedMacros(ArrayRef<Token> Toks);
7341
7342	ExprResult BuildPredefinedExpr(SourceLocation Loc, PredefinedIdentKind IK);
7343	ExprResult ActOnPredefinedExpr(SourceLocation Loc, tok::TokenKind Kind);
7344	ExprResult ActOnIntegerConstant(SourceLocation Loc, int64_t Val);
7345
7346	bool CheckLoopHintExpr(Expr E, SourceLocation Loc, bool* AllowZero);
7347
7348	ExprResult ActOnNumericConstant(const Token &Tok, Scope UDLScope = nullptr*);
7349	ExprResult ActOnCharacterConstant(const Token &Tok,
7350	Scope UDLScope = nullptr*);
7351	ExprResult ActOnParenExpr(SourceLocation L, SourceLocation R, Expr *E);
7352	ExprResult ActOnParenListExpr(SourceLocation L, SourceLocation R,
7353	MultiExprArg Val);
7354	ExprResult ActOnCXXParenListInitExpr(ArrayRef<Expr *> Args, QualType T,
7355	unsigned NumUserSpecifiedExprs,
7356	SourceLocation InitLoc,
7357	SourceLocation LParenLoc,
7358	SourceLocation RParenLoc);
7359
7360	/// ActOnStringLiteral - The specified tokens were lexed as pasted string
7361	/// fragments (e.g. "foo" "bar" L"baz"). The result string has to handle
7362	/// string concatenation ([C99 5.1.1.2, translation phase #6]), so it may come
7363	/// from multiple tokens. However, the common case is that StringToks points
7364	/// to one string.
7365	ExprResult ActOnStringLiteral(ArrayRef<Token> StringToks,
7366	Scope UDLScope = nullptr*);
7367
7368	ExprResult ActOnUnevaluatedStringLiteral(ArrayRef<Token> StringToks);
7369
7370	/// ControllingExprOrType is either an opaque pointer coming out of a
7371	/// ParsedType or an Expr . FIXME: it'd be better to split this interface*
7372	/// into two so we don't take a void , but that's awkward because one of*
7373	/// the operands is either a ParsedType or an Expr , which doesn't lend*
7374	/// itself to generic code very well.
7375	ExprResult ActOnGenericSelectionExpr(SourceLocation KeyLoc,
7376	SourceLocation DefaultLoc,
7377	SourceLocation RParenLoc,
7378	bool PredicateIsExpr,
7379	void *ControllingExprOrType,
7380	ArrayRef<ParsedType> ArgTypes,
7381	ArrayRef<Expr *> ArgExprs);
7382	/// ControllingExprOrType is either a TypeSourceInfo or an Expr . FIXME:
7383	/// it'd be better to split this interface into two so we don't take a
7384	/// void , but see the FIXME on ActOnGenericSelectionExpr as to why that*
7385	/// isn't a trivial change.
7386	ExprResult CreateGenericSelectionExpr(SourceLocation KeyLoc,
7387	SourceLocation DefaultLoc,
7388	SourceLocation RParenLoc,
7389	bool PredicateIsExpr,
7390	void *ControllingExprOrType,
7391	ArrayRef<TypeSourceInfo *> Types,
7392	ArrayRef<Expr *> Exprs);
7393
7394	// Binary/Unary Operators. 'Tok' is the token for the operator.
7395	ExprResult CreateBuiltinUnaryOp(SourceLocation OpLoc, UnaryOperatorKind Opc,
7396	Expr InputExpr, bool* IsAfterAmp = false);
7397	ExprResult BuildUnaryOp(Scope *S, SourceLocation OpLoc, UnaryOperatorKind Opc,
7398	Expr Input, bool* IsAfterAmp = false);
7399
7400	/// Unary Operators. 'Tok' is the token for the operator.
7401	ExprResult ActOnUnaryOp(Scope *S, SourceLocation OpLoc, tok::TokenKind Op,
7402	Expr Input, bool* IsAfterAmp = false);
7403
7404	/// Determine whether the given expression is a qualified member
7405	/// access expression, of a form that could be turned into a pointer to member
7406	/// with the address-of operator.
7407	bool isQualifiedMemberAccess(Expr *E);
7408	bool CheckUseOfCXXMethodAsAddressOfOperand(SourceLocation OpLoc,
7409	const Expr *Op,
7410	const CXXMethodDecl *MD);
7411
7412	/// CheckAddressOfOperand - The operand of & must be either a function
7413	/// designator or an lvalue designating an object. If it is an lvalue, the
7414	/// object cannot be declared with storage class register or be a bit field.
7415	/// Note: The usual conversions are not* applied to the operand of the &*
7416	/// operator (C99 6.3.2.1p[2-4]), and its result is never an lvalue.
7417	/// In C++, the operand might be an overloaded function name, in which case
7418	/// we allow the '&' but retain the overloaded-function type.
7419	QualType CheckAddressOfOperand(ExprResult &Operand, SourceLocation OpLoc);
7420
7421	/// ActOnAlignasTypeArgument - Handle @c alignas(type-id) and @c
7422	/// _Alignas(type-name) .
7423	/// [dcl.align] An alignment-specifier of the form
7424	/// alignas(type-id) has the same effect as alignas(alignof(type-id)).
7425	///
7426	/// [N1570 6.7.5] _Alignas(type-name) is equivalent to
7427	/// _Alignas(_Alignof(type-name)).
7428	bool ActOnAlignasTypeArgument(StringRef KWName, ParsedType Ty,
7429	SourceLocation OpLoc, SourceRange R);
7430	bool CheckAlignasTypeArgument(StringRef KWName, TypeSourceInfo *TInfo,
7431	SourceLocation OpLoc, SourceRange R);
7432
7433	/// Build a sizeof or alignof expression given a type operand.
7434	ExprResult CreateUnaryExprOrTypeTraitExpr(TypeSourceInfo *TInfo,
7435	SourceLocation OpLoc,
7436	UnaryExprOrTypeTrait ExprKind,
7437	SourceRange R);
7438
7439	/// Build a sizeof or alignof expression given an expression
7440	/// operand.
7441	ExprResult CreateUnaryExprOrTypeTraitExpr(Expr *E, SourceLocation OpLoc,
7442	UnaryExprOrTypeTrait ExprKind);
7443
7444	/// ActOnUnaryExprOrTypeTraitExpr - Handle @c sizeof(type) and @c sizeof @c
7445	/// expr and the same for @c alignof and @c __alignof
7446	/// Note that the ArgRange is invalid if isType is false.
7447	ExprResult ActOnUnaryExprOrTypeTraitExpr(SourceLocation OpLoc,
7448	UnaryExprOrTypeTrait ExprKind,
7449	bool IsType, void *TyOrEx,
7450	SourceRange ArgRange);
7451
7452	/// Check for operands with placeholder types and complain if found.
7453	/// Returns ExprError() if there was an error and no recovery was possible.
7454	ExprResult CheckPlaceholderExpr(Expr *E);
7455	bool CheckVecStepExpr(Expr *E);
7456
7457	/// Check the constraints on expression operands to unary type expression
7458	/// and type traits.
7459	///
7460	/// Completes any types necessary and validates the constraints on the operand
7461	/// expression. The logic mostly mirrors the type-based overload, but may
7462	/// modify the expression as it completes the type for that expression through
7463	/// template instantiation, etc.
7464	bool CheckUnaryExprOrTypeTraitOperand(Expr *E, UnaryExprOrTypeTrait ExprKind);
7465
7466	/// Check the constraints on operands to unary expression and type
7467	/// traits.
7468	///
7469	/// This will complete any types necessary, and validate the various
7470	/// constraints on those operands.
7471	///
7472	/// The UsualUnaryConversions() function is not* called by this routine.*
7473	/// C99 6.3.2.1p[2-4] all state:
7474	/// Except when it is the operand of the sizeof operator ...
7475	///
7476	/// C++ [expr.sizeof]p4
7477	/// The lvalue-to-rvalue, array-to-pointer, and function-to-pointer
7478	/// standard conversions are not applied to the operand of sizeof.
7479	///
7480	/// This policy is followed for all of the unary trait expressions.
7481	bool CheckUnaryExprOrTypeTraitOperand(QualType ExprType, SourceLocation OpLoc,
7482	SourceRange ExprRange,
7483	UnaryExprOrTypeTrait ExprKind,
7484	StringRef KWName);
7485
7486	ExprResult ActOnPostfixUnaryOp(Scope *S, SourceLocation OpLoc,
7487	tok::TokenKind Kind, Expr *Input);
7488
7489	ExprResult ActOnArraySubscriptExpr(Scope S, Expr Base, SourceLocation LLoc,
7490	MultiExprArg ArgExprs,
7491	SourceLocation RLoc);
7492	ExprResult CreateBuiltinArraySubscriptExpr(Expr *Base, SourceLocation LLoc,
7493	Expr *Idx, SourceLocation RLoc);
7494
7495	ExprResult CreateBuiltinMatrixSingleSubscriptExpr(Expr Base, Expr RowIdx,
7496	SourceLocation RBLoc);
7497
7498	ExprResult CreateBuiltinMatrixSubscriptExpr(Expr Base, Expr RowIdx,
7499	Expr *ColumnIdx,
7500	SourceLocation RBLoc);
7501
7502	/// ConvertArgumentsForCall - Converts the arguments specified in
7503	/// Args/NumArgs to the parameter types of the function FDecl with
7504	/// function prototype Proto. Call is the call expression itself, and
7505	/// Fn is the function expression. For a C++ member function, this
7506	/// routine does not attempt to convert the object argument. Returns
7507	/// true if the call is ill-formed.
7508	bool ConvertArgumentsForCall(CallExpr Call, Expr Fn, FunctionDecl *FDecl,
7509	const FunctionProtoType *Proto,
7510	ArrayRef<Expr *> Args, SourceLocation RParenLoc,
7511	bool ExecConfig = false);
7512
7513	/// CheckStaticArrayArgument - If the given argument corresponds to a static
7514	/// array parameter, check that it is non-null, and that if it is formed by
7515	/// array-to-pointer decay, the underlying array is sufficiently large.
7516	///
7517	/// C99 6.7.5.3p7: If the keyword static also appears within the [ and ] of
7518	/// the array type derivation, then for each call to the function, the value
7519	/// of the corresponding actual argument shall provide access to the first
7520	/// element of an array with at least as many elements as specified by the
7521	/// size expression.
7522	void CheckStaticArrayArgument(SourceLocation CallLoc, ParmVarDecl *Param,
7523	const Expr *ArgExpr);
7524
7525	/// ActOnCallExpr - Handle a call to Fn with the specified array of arguments.
7526	/// This provides the location of the left/right parens and a list of comma
7527	/// locations.
7528	ExprResult ActOnCallExpr(Scope S, Expr Fn, SourceLocation LParenLoc,
7529	MultiExprArg ArgExprs, SourceLocation RParenLoc,
7530	Expr ExecConfig = nullptr*);
7531
7532	/// BuildCallExpr - Handle a call to Fn with the specified array of arguments.
7533	/// This provides the location of the left/right parens and a list of comma
7534	/// locations.
7535	ExprResult BuildCallExpr(Scope S, Expr Fn, SourceLocation LParenLoc,
7536	MultiExprArg ArgExprs, SourceLocation RParenLoc,
7537	Expr ExecConfig = nullptr*,
7538	bool IsExecConfig = false,
7539	bool AllowRecovery = false);
7540
7541	/// BuildBuiltinCallExpr - Create a call to a builtin function specified by Id
7542	// with the specified CallArgs
7543	Expr *BuildBuiltinCallExpr(SourceLocation Loc, Builtin::ID Id,
7544	MultiExprArg CallArgs);
7545
7546	using ADLCallKind = CallExpr::ADLCallKind;
7547
7548	/// BuildResolvedCallExpr - Build a call to a resolved expression,
7549	/// i.e. an expression not of \p OverloadTy. The expression should
7550	/// unary-convert to an expression of function-pointer or
7551	/// block-pointer type.
7552	///
7553	/// \param NDecl the declaration being called, if available
7554	ExprResult
7555	BuildResolvedCallExpr(Expr Fn, NamedDecl NDecl, SourceLocation LParenLoc,
7556	ArrayRef<Expr *> Arg, SourceLocation RParenLoc,
7557	Expr Config = nullptr, bool* IsExecConfig = false,
7558	ADLCallKind UsesADL = ADLCallKind::NotADL);
7559
7560	ExprResult ActOnCastExpr(Scope *S, SourceLocation LParenLoc, Declarator &D,
7561	ParsedType &Ty, SourceLocation RParenLoc,
7562	Expr *CastExpr);
7563
7564	/// Prepares for a scalar cast, performing all the necessary stages
7565	/// except the final cast and returning the kind required.
7566	CastKind PrepareScalarCast(ExprResult &src, QualType destType);
7567
7568	/// Build an altivec or OpenCL literal.
7569	ExprResult BuildVectorLiteral(SourceLocation LParenLoc,
7570	SourceLocation RParenLoc, Expr *E,
7571	TypeSourceInfo *TInfo);
7572
7573	/// This is not an AltiVec-style cast or or C++ direct-initialization, so turn
7574	/// the ParenListExpr into a sequence of comma binary operators.
7575	ExprResult MaybeConvertParenListExprToParenExpr(Scope S, Expr ME);
7576
7577	ExprResult ActOnCompoundLiteral(SourceLocation LParenLoc, ParsedType Ty,
7578	SourceLocation RParenLoc, Expr *InitExpr);
7579
7580	ExprResult BuildCompoundLiteralExpr(SourceLocation LParenLoc,
7581	TypeSourceInfo *TInfo,
7582	SourceLocation RParenLoc,
7583	Expr *LiteralExpr);
7584
7585	ExprResult ActOnInitList(SourceLocation LBraceLoc, MultiExprArg InitArgList,
7586	SourceLocation RBraceLoc);
7587
7588	ExprResult BuildInitList(SourceLocation LBraceLoc, MultiExprArg InitArgList,
7589	SourceLocation RBraceLoc);
7590
7591	/// Binary Operators. 'Tok' is the token for the operator.
7592	ExprResult ActOnBinOp(Scope *S, SourceLocation TokLoc, tok::TokenKind Kind,
7593	Expr LHSExpr, Expr RHSExpr);
7594	ExprResult BuildBinOp(Scope *S, SourceLocation OpLoc, BinaryOperatorKind Opc,
7595	Expr LHSExpr, Expr RHSExpr,
7596	bool ForFoldExpression = false);
7597
7598	/// CreateBuiltinBinOp - Creates a new built-in binary operation with
7599	/// operator @p Opc at location @c TokLoc. This routine only supports
7600	/// built-in operations; ActOnBinOp handles overloaded operators.
7601	ExprResult CreateBuiltinBinOp(SourceLocation OpLoc, BinaryOperatorKind Opc,
7602	Expr LHSExpr, Expr RHSExpr,
7603	bool ForFoldExpression = false);
7604	void LookupBinOp(Scope *S, SourceLocation OpLoc, BinaryOperatorKind Opc,
7605	UnresolvedSetImpl &Functions);
7606
7607	/// Look for instances where it is likely the comma operator is confused with
7608	/// another operator. There is an explicit list of acceptable expressions for
7609	/// the left hand side of the comma operator, otherwise emit a warning.
7610	void DiagnoseCommaOperator(const Expr *LHS, SourceLocation Loc);
7611
7612	/// ActOnConditionalOp - Parse a ?: operation. Note that 'LHS' may be null
7613	/// in the case of a the GNU conditional expr extension.
7614	ExprResult ActOnConditionalOp(SourceLocation QuestionLoc,
7615	SourceLocation ColonLoc, Expr *CondExpr,
7616	Expr LHSExpr, Expr RHSExpr);
7617
7618	/// ActOnAddrLabel - Parse the GNU address of label extension: "&&foo".
7619	ExprResult ActOnAddrLabel(SourceLocation OpLoc, SourceLocation LabLoc,
7620	LabelDecl *TheDecl);
7621
7622	void ActOnStartStmtExpr();
7623	ExprResult ActOnStmtExpr(Scope S, SourceLocation LPLoc, Stmt SubStmt,
7624	SourceLocation RPLoc);
7625	ExprResult BuildStmtExpr(SourceLocation LPLoc, Stmt *SubStmt,
7626	SourceLocation RPLoc, unsigned TemplateDepth);
7627	// Handle the final expression in a statement expression.
7628	ExprResult ActOnStmtExprResult(ExprResult E);
7629	void ActOnStmtExprError();
7630
7631	// __builtin_offsetof(type, identifier(.identifier\|[expr]))*
7632	struct OffsetOfComponent {
7633	SourceLocation LocStart, LocEnd;
7634	bool isBrackets; // true if [expr], false if .ident
7635	union {
7636	IdentifierInfo *IdentInfo;
7637	Expr *E;
7638	} U;
7639	};
7640
7641	/// __builtin_offsetof(type, a.b[123][456].c)
7642	ExprResult BuildBuiltinOffsetOf(SourceLocation BuiltinLoc,
7643	TypeSourceInfo *TInfo,
7644	ArrayRef<OffsetOfComponent> Components,
7645	SourceLocation RParenLoc);
7646	ExprResult ActOnBuiltinOffsetOf(Scope *S, SourceLocation BuiltinLoc,
7647	SourceLocation TypeLoc,
7648	ParsedType ParsedArgTy,
7649	ArrayRef<OffsetOfComponent> Components,
7650	SourceLocation RParenLoc);
7651
7652	// __builtin_choose_expr(constExpr, expr1, expr2)
7653	ExprResult ActOnChooseExpr(SourceLocation BuiltinLoc, Expr *CondExpr,
7654	Expr LHSExpr, Expr RHSExpr,
7655	SourceLocation RPLoc);
7656
7657	// __builtin_va_arg(expr, type)
7658	ExprResult ActOnVAArg(SourceLocation BuiltinLoc, Expr *E, ParsedType Ty,
7659	SourceLocation RPLoc);
7660	ExprResult BuildVAArgExpr(SourceLocation BuiltinLoc, Expr *E,
7661	TypeSourceInfo *TInfo, SourceLocation RPLoc);
7662
7663	// __builtin_LINE(), __builtin_FUNCTION(), __builtin_FUNCSIG(),
7664	// __builtin_FILE(), __builtin_COLUMN(), __builtin_source_location()
7665	ExprResult ActOnSourceLocExpr(SourceLocIdentKind Kind,
7666	SourceLocation BuiltinLoc,
7667	SourceLocation RPLoc);
7668
7669	// #embed
7670	ExprResult ActOnEmbedExpr(SourceLocation EmbedKeywordLoc,
7671	StringLiteral *BinaryData, StringRef FileName);
7672
7673	// Build a potentially resolved SourceLocExpr.
7674	ExprResult BuildSourceLocExpr(SourceLocIdentKind Kind, QualType ResultTy,
7675	SourceLocation BuiltinLoc, SourceLocation RPLoc,
7676	DeclContext *ParentContext);
7677
7678	// __null
7679	ExprResult ActOnGNUNullExpr(SourceLocation TokenLoc);
7680
7681	bool CheckCaseExpression(Expr *E);
7682
7683	//===------------------------- "Block" Extension ------------------------===//
7684
7685	/// ActOnBlockStart - This callback is invoked when a block literal is
7686	/// started.
7687	void ActOnBlockStart(SourceLocation CaretLoc, Scope *CurScope);
7688
7689	/// ActOnBlockArguments - This callback allows processing of block arguments.
7690	/// If there are no arguments, this is still invoked.
7691	void ActOnBlockArguments(SourceLocation CaretLoc, Declarator &ParamInfo,
7692	Scope *CurScope);
7693
7694	/// ActOnBlockError - If there is an error parsing a block, this callback
7695	/// is invoked to pop the information about the block from the action impl.
7696	void ActOnBlockError(SourceLocation CaretLoc, Scope *CurScope);
7697
7698	/// ActOnBlockStmtExpr - This is called when the body of a block statement
7699	/// literal was successfully completed. ^(int x){...}
7700	ExprResult ActOnBlockStmtExpr(SourceLocation CaretLoc, Stmt *Body,
7701	Scope *CurScope);
7702
7703	//===---------------------------- Clang Extensions ----------------------===//
7704
7705	/// ActOnConvertVectorExpr - create a new convert-vector expression from the
7706	/// provided arguments.
7707	///
7708	/// __builtin_convertvector( value, dst type )
7709	///
7710	ExprResult ActOnConvertVectorExpr(Expr *E, ParsedType ParsedDestTy,
7711	SourceLocation BuiltinLoc,
7712	SourceLocation RParenLoc);
7713
7714	//===---------------------------- OpenCL Features -----------------------===//
7715
7716	/// Parse a __builtin_astype expression.
7717	///
7718	/// __builtin_astype( value, dst type )
7719	///
7720	ExprResult ActOnAsTypeExpr(Expr *E, ParsedType ParsedDestTy,
7721	SourceLocation BuiltinLoc,
7722	SourceLocation RParenLoc);
7723
7724	/// Create a new AsTypeExpr node (bitcast) from the arguments.
7725	ExprResult BuildAsTypeExpr(Expr *E, QualType DestTy,
7726	SourceLocation BuiltinLoc,
7727	SourceLocation RParenLoc);
7728
7729	/// Attempts to produce a RecoveryExpr after some AST node cannot be created.
7730	ExprResult CreateRecoveryExpr(SourceLocation Begin, SourceLocation End,
7731	ArrayRef<Expr *> SubExprs,
7732	QualType T = QualType ());
7733
7734	/// Cast a base object to a member's actual type.
7735	///
7736	/// There are two relevant checks:
7737	///
7738	/// C++ [class.access.base]p7:
7739	///
7740	/// If a class member access operator [...] is used to access a non-static
7741	/// data member or non-static member function, the reference is ill-formed
7742	/// if the left operand [...] cannot be implicitly converted to a pointer to
7743	/// the naming class of the right operand.
7744	///
7745	/// C++ [expr.ref]p7:
7746	///
7747	/// If E2 is a non-static data member or a non-static member function, the
7748	/// program is ill-formed if the class of which E2 is directly a member is
7749	/// an ambiguous base (11.8) of the naming class (11.9.3) of E2.
7750	///
7751	/// Note that the latter check does not consider access; the access of the
7752	/// "real" base class is checked as appropriate when checking the access of
7753	/// the member name.
7754	ExprResult PerformObjectMemberConversion(Expr *From,
7755	NestedNameSpecifier Qualifier,
7756	NamedDecl *FoundDecl,
7757	NamedDecl *Member);
7758
7759	/// CheckCallReturnType - Checks that a call expression's return type is
7760	/// complete. Returns true on failure. The location passed in is the location
7761	/// that best represents the call.
7762	bool CheckCallReturnType(QualType ReturnType, SourceLocation Loc,
7763	CallExpr CE, FunctionDecl FD);
7764
7765	/// Emit a warning for all pending noderef expressions that we recorded.
7766	void WarnOnPendingNoDerefs(ExpressionEvaluationContextRecord &Rec);
7767
7768	ExprResult BuildCXXDefaultInitExpr(SourceLocation Loc, FieldDecl *Field);
7769
7770	/// Instantiate or parse a C++ default argument expression as necessary.
7771	/// Return true on error.
7772	bool CheckCXXDefaultArgExpr(SourceLocation CallLoc, FunctionDecl *FD,
7773	ParmVarDecl Param, Expr Init = nullptr,
7774	bool SkipImmediateInvocations = true);
7775
7776	/// BuildCXXDefaultArgExpr - Creates a CXXDefaultArgExpr, instantiating
7777	/// the default expr if needed.
7778	ExprResult BuildCXXDefaultArgExpr(SourceLocation CallLoc, FunctionDecl *FD,
7779	ParmVarDecl Param, Expr Init = nullptr);
7780
7781	/// Wrap the expression in a ConstantExpr if it is a potential immediate
7782	/// invocation.
7783	ExprResult CheckForImmediateInvocation(ExprResult E, FunctionDecl *Decl);
7784
7785	void MarkExpressionAsImmediateEscalating(Expr *E);
7786
7787	// Check that the SME attributes for PSTATE.ZA and PSTATE.SM are compatible.
7788	bool IsInvalidSMECallConversion(QualType FromType, QualType ToType);
7789
7790	/// Abstract base class used for diagnosing integer constant
7791	/// expression violations.
7792	class VerifyICEDiagnoser {
7793	public:
7794	bool Suppress;
7795
7796	VerifyICEDiagnoser(bool Suppress = false) : Suppress(Suppress) {}
7797
7798	virtual SemaDiagnosticBuilder
7799	diagnoseNotICEType(Sema &S, SourceLocation Loc, QualType T);
7800	virtual SemaDiagnosticBuilder diagnoseNotICE(Sema &S,
7801	SourceLocation Loc) = `0`;
7802	virtual SemaDiagnosticBuilder diagnoseFold(Sema &S, SourceLocation Loc);
7803	virtual ~VerifyICEDiagnoser() {}
7804	};
7805
7806	/// VerifyIntegerConstantExpression - Verifies that an expression is an ICE,
7807	/// and reports the appropriate diagnostics. Returns false on success.
7808	/// Can optionally return the value of the expression.
7809	ExprResult
7810	VerifyIntegerConstantExpression(Expr E, llvm::APSInt Result,
7811	VerifyICEDiagnoser &Diagnoser,
7812	AllowFoldKind CanFold = AllowFoldKind::No);
7813	ExprResult
7814	VerifyIntegerConstantExpression(Expr E, llvm::APSInt Result,
7815	unsigned DiagID,
7816	AllowFoldKind CanFold = AllowFoldKind::No);
7817	ExprResult
7818	VerifyIntegerConstantExpression(Expr E, llvm::APSInt Result = nullptr,
7819	AllowFoldKind CanFold = AllowFoldKind::No);
7820	ExprResult
7821	VerifyIntegerConstantExpression(Expr *E,
7822	AllowFoldKind CanFold = AllowFoldKind::No) {
7823	return VerifyIntegerConstantExpression(E, Result: nullptr, CanFold);
7824	}
7825
7826	/// DiagnoseAssignmentAsCondition - Given that an expression is
7827	/// being used as a boolean condition, warn if it's an assignment.
7828	void DiagnoseAssignmentAsCondition(Expr *E);
7829
7830	/// Redundant parentheses over an equality comparison can indicate
7831	/// that the user intended an assignment used as condition.
7832	void DiagnoseEqualityWithExtraParens(ParenExpr *ParenE);
7833
7834	class FullExprArg {
7835	public:
7836	FullExprArg() : E(nullptr) {}
7837	FullExprArg(Sema &actions) : E(nullptr) {}
7838
7839	ExprResult release() { return E; }
7840
7841	Expr get() const* { return E; }
7842
7843	Expr *operator->() { return E; }
7844
7845	private:
7846	// FIXME: No need to make the entire Sema class a friend when it's just
7847	// Sema::MakeFullExpr that needs access to the constructor below.
7848	friend class Sema;
7849
7850	explicit FullExprArg(Expr *expr) : E(expr) {}
7851
7852	Expr *E;
7853	};
7854
7855	FullExprArg MakeFullExpr(Expr *Arg) {
7856	return MakeFullExpr(Arg, CC: Arg ? Arg->getExprLoc() : SourceLocation ());
7857	}
7858	FullExprArg MakeFullExpr(Expr *Arg, SourceLocation CC) {
7859	return FullExprArg (
7860	ActOnFinishFullExpr(Expr: Arg, CC, /DiscardedValue/ DiscardedValue: false).get());
7861	}
7862	FullExprArg MakeFullDiscardedValueExpr(Expr *Arg) {
7863	ExprResult FE =
7864	ActOnFinishFullExpr(Expr: Arg, CC: Arg ? Arg->getExprLoc() : SourceLocation (),
7865	/DiscardedValue/ DiscardedValue: true);
7866	return FullExprArg (FE.get());
7867	}
7868
7869	class ConditionResult {
7870	Decl *ConditionVar;
7871	ExprResult Condition;
7872	bool Invalid;
7873	std::optional<bool> KnownValue;
7874
7875	friend class Sema;
7876	ConditionResult(Sema &S, Decl *ConditionVar, ExprResult Condition,
7877	bool IsConstexpr)
7878	: ConditionVar(ConditionVar), Condition (Condition), Invalid(false) {
7879	if (IsConstexpr && Condition.get()) {
7880	if (std::optional<llvm::APSInt> Val =
7881	Condition.get()->getIntegerConstantExpr(Ctx: S.Context)) {
7882	KnownValue = !!(*Val);
7883	}
7884	}
7885	}
7886	explicit ConditionResult(bool Invalid)
7887	: ConditionVar(nullptr), Condition (Invalid), Invalid(Invalid),
7888	KnownValue (std::nullopt) {}
7889
7890	public:
7891	ConditionResult() : ConditionResult (false) {}
7892	bool isInvalid() const { return Invalid; }
7893	std::pair<VarDecl , Expr > get() const {
7894	return std::make_pair(x: cast_or_null<VarDecl>(Val: ConditionVar),
7895	y: Condition.get());
7896	}
7897	std::optional<bool> getKnownValue() const { return KnownValue; }
7898	};
7899	static ConditionResult ConditionError() { return ConditionResult (true); }
7900
7901	/// CheckBooleanCondition - Diagnose problems involving the use of
7902	/// the given expression as a boolean condition (e.g. in an if
7903	/// statement). Also performs the standard function and array
7904	/// decays, possibly changing the input variable.
7905	///
7906	/// \param Loc - A location associated with the condition, e.g. the
7907	/// 'if' keyword.
7908	/// \return true iff there were any errors
7909	ExprResult CheckBooleanCondition(SourceLocation Loc, Expr *E,
7910	bool IsConstexpr = false);
7911
7912	enum class ConditionKind {
7913	Boolean, ///< A boolean condition, from 'if', 'while', 'for', or 'do'.
7914	ConstexprIf, ///< A constant boolean condition from 'if constexpr'.
7915	Switch ///< An integral condition for a 'switch' statement.
7916	};
7917
7918	ConditionResult ActOnCondition(Scope S, SourceLocation Loc, Expr SubExpr,
7919	ConditionKind CK, bool MissingOK = false);
7920
7921	QualType CheckConditionalOperands( // C99 6.5.15
7922	ExprResult &Cond, ExprResult &LHS, ExprResult &RHS, ExprValueKind &VK,
7923	ExprObjectKind &OK, SourceLocation QuestionLoc);
7924
7925	/// Emit a specialized diagnostic when one expression is a null pointer
7926	/// constant and the other is not a pointer. Returns true if a diagnostic is
7927	/// emitted.
7928	bool DiagnoseConditionalForNull(const Expr LHSExpr, const* Expr *RHSExpr,
7929	SourceLocation QuestionLoc);
7930
7931	/// type checking for vector binary operators.
7932	QualType CheckVectorOperands(ExprResult &LHS, ExprResult &RHS,
7933	SourceLocation Loc, bool IsCompAssign,
7934	bool AllowBothBool, bool AllowBoolConversion,
7935	bool AllowBoolOperation, bool ReportInvalid);
7936
7937	/// Return a signed ext_vector_type that is of identical size and number of
7938	/// elements. For floating point vectors, return an integer type of identical
7939	/// size and number of elements. In the non ext_vector_type case, search from
7940	/// the largest type to the smallest type to avoid cases where long long ==
7941	/// long, where long gets picked over long long.
7942	QualType GetSignedVectorType(QualType V);
7943	QualType GetSignedSizelessVectorType(QualType V);
7944
7945	/// CheckVectorCompareOperands - vector comparisons are a clang extension that
7946	/// operates on extended vector types. Instead of producing an IntTy result,
7947	/// like a scalar comparison, a vector comparison produces a vector of integer
7948	/// types.
7949	QualType CheckVectorCompareOperands(ExprResult &LHS, ExprResult &RHS,
7950	SourceLocation Loc,
7951	BinaryOperatorKind Opc);
7952	QualType CheckSizelessVectorCompareOperands(ExprResult &LHS, ExprResult &RHS,
7953	SourceLocation Loc,
7954	BinaryOperatorKind Opc);
7955	QualType CheckVectorLogicalOperands(ExprResult &LHS, ExprResult &RHS,
7956	SourceLocation Loc,
7957	BinaryOperatorKind Opc);
7958	QualType CheckMatrixLogicalOperands(ExprResult &LHS, ExprResult &RHS,
7959	SourceLocation Loc,
7960	BinaryOperatorKind Opc);
7961	// type checking for sizeless vector binary operators.
7962	QualType CheckSizelessVectorOperands(ExprResult &LHS, ExprResult &RHS,
7963	SourceLocation Loc, bool IsCompAssign,
7964	ArithConvKind OperationKind);
7965
7966	/// Type checking for matrix binary operators.
7967	QualType CheckMatrixElementwiseOperands(ExprResult &LHS, ExprResult &RHS,
7968	SourceLocation Loc,
7969	bool IsCompAssign);
7970	QualType CheckMatrixMultiplyOperands(ExprResult &LHS, ExprResult &RHS,
7971	SourceLocation Loc, bool IsCompAssign);
7972
7973	/// Are the two types SVE-bitcast-compatible types? I.e. is bitcasting from
7974	/// the first SVE type (e.g. an SVE VLAT) to the second type (e.g. an SVE
7975	/// VLST) allowed?
7976	///
7977	/// This will also return false if the two given types do not make sense from
7978	/// the perspective of SVE bitcasts.
7979	bool isValidSveBitcast(QualType srcType, QualType destType);
7980
7981	/// Are the two types matrix types and do they have the same dimensions i.e.
7982	/// do they have the same number of rows and the same number of columns?
7983	bool areMatrixTypesOfTheSameDimension(QualType srcTy, QualType destTy);
7984
7985	bool areVectorTypesSameSize(QualType srcType, QualType destType);
7986
7987	/// Are the two types lax-compatible vector types? That is, given
7988	/// that one of them is a vector, do they have equal storage sizes,
7989	/// where the storage size is the number of elements times the element
7990	/// size?
7991	///
7992	/// This will also return false if either of the types is neither a
7993	/// vector nor a real type.
7994	bool areLaxCompatibleVectorTypes(QualType srcType, QualType destType);
7995
7996	/// Is this a legal conversion between two types, one of which is
7997	/// known to be a vector type?
7998	bool isLaxVectorConversion(QualType srcType, QualType destType);
7999
8000	// This returns true if at least one of the types is an altivec vector.
8001	bool anyAltivecTypes(QualType srcType, QualType destType);
8002
8003	// type checking C++ declaration initializers (C++ [dcl.init]).
8004
8005	/// Check a cast of an unknown-any type. We intentionally only
8006	/// trigger this for C-style casts.
8007	ExprResult checkUnknownAnyCast(SourceRange TypeRange, QualType CastType,
8008	Expr *CastExpr, CastKind &CastKind,
8009	ExprValueKind &VK, CXXCastPath &Path);
8010
8011	/// Force an expression with unknown-type to an expression of the
8012	/// given type.
8013	ExprResult forceUnknownAnyToType(Expr *E, QualType ToType);
8014
8015	/// Type-check an expression that's being passed to an
8016	/// __unknown_anytype parameter.
8017	ExprResult checkUnknownAnyArg(SourceLocation callLoc, Expr *result,
8018	QualType &paramType);
8019
8020	// CheckMatrixCast - Check type constraints for matrix casts.
8021	// We allow casting between matrixes of the same dimensions i.e. when they
8022	// have the same number of rows and column. Returns true if the cast is
8023	// invalid.
8024	bool CheckMatrixCast(SourceRange R, QualType DestTy, QualType SrcTy,
8025	CastKind &Kind);
8026
8027	// CheckVectorCast - check type constraints for vectors.
8028	// Since vectors are an extension, there are no C standard reference for this.
8029	// We allow casting between vectors and integer datatypes of the same size.
8030	// returns true if the cast is invalid
8031	bool CheckVectorCast(SourceRange R, QualType VectorTy, QualType Ty,
8032	CastKind &Kind);
8033
8034	/// Prepare `SplattedExpr` for a vector splat operation, adding
8035	/// implicit casts if necessary.
8036	ExprResult prepareVectorSplat(QualType VectorTy, Expr *SplattedExpr);
8037
8038	/// Prepare `SplattedExpr` for a matrix splat operation, adding
8039	/// implicit casts if necessary.
8040	ExprResult prepareMatrixSplat(QualType MatrixTy, Expr *SplattedExpr);
8041
8042	// CheckExtVectorCast - check type constraints for extended vectors.
8043	// Since vectors are an extension, there are no C standard reference for this.
8044	// We allow casting between vectors and integer datatypes of the same size,
8045	// or vectors and the element type of that vector.
8046	// returns the cast expr
8047	ExprResult CheckExtVectorCast(SourceRange R, QualType DestTy, Expr *CastExpr,
8048	CastKind &Kind);
8049
8050	QualType PreferredConditionType(ConditionKind K) const {
8051	return K == ConditionKind::Switch ? Context.IntTy : Context.BoolTy;
8052	}
8053
8054	// UsualUnaryConversions - promotes integers (C99 6.3.1.1p2), converts
8055	// functions and arrays to their respective pointers (C99 6.3.2.1), and
8056	// promotes floating-piont types according to the language semantics.
8057	ExprResult UsualUnaryConversions(Expr *E);
8058
8059	// UsualUnaryFPConversions - promotes floating-point types according to the
8060	// current language semantics.
8061	ExprResult UsualUnaryFPConversions(Expr *E);
8062
8063	/// CallExprUnaryConversions - a special case of an unary conversion
8064	/// performed on a function designator of a call expression.
8065	ExprResult CallExprUnaryConversions(Expr *E);
8066
8067	// DefaultFunctionArrayConversion - converts functions and arrays
8068	// to their respective pointers (C99 6.3.2.1).
8069	ExprResult DefaultFunctionArrayConversion(Expr E, bool* Diagnose = true);
8070
8071	// DefaultFunctionArrayLvalueConversion - converts functions and
8072	// arrays to their respective pointers and performs the
8073	// lvalue-to-rvalue conversion.
8074	ExprResult DefaultFunctionArrayLvalueConversion(Expr *E,
8075	bool Diagnose = true);
8076
8077	// DefaultLvalueConversion - performs lvalue-to-rvalue conversion on
8078	// the operand. This function is a no-op if the operand has a function type
8079	// or an array type.
8080	ExprResult DefaultLvalueConversion(Expr *E);
8081
8082	// DefaultArgumentPromotion (C99 6.5.2.2p6). Used for function calls that
8083	// do not have a prototype. Integer promotions are performed on each
8084	// argument, and arguments that have type float are promoted to double.
8085	ExprResult DefaultArgumentPromotion(Expr *E);
8086
8087	VariadicCallType getVariadicCallType(FunctionDecl *FDecl,
8088	const FunctionProtoType *Proto,
8089	Expr *Fn);
8090
8091	/// Determine the degree of POD-ness for an expression.
8092	/// Incomplete types are considered POD, since this check can be performed
8093	/// when we're in an unevaluated context.
8094	VarArgKind isValidVarArgType(const QualType &Ty);
8095
8096	/// Check to see if the given expression is a valid argument to a variadic
8097	/// function, issuing a diagnostic if not.
8098	void checkVariadicArgument(const Expr *E, VariadicCallType CT);
8099
8100	/// GatherArgumentsForCall - Collector argument expressions for various
8101	/// form of call prototypes.
8102	bool GatherArgumentsForCall(
8103	SourceLocation CallLoc, FunctionDecl *FDecl,
8104	const FunctionProtoType Proto, unsigned* FirstParam,
8105	ArrayRef<Expr > Args, SmallVectorImpl<Expr > &AllArgs,
8106	VariadicCallType CallType = VariadicCallType::DoesNotApply,
8107	bool AllowExplicit = false, bool IsListInitialization = false);
8108
8109	// DefaultVariadicArgumentPromotion - Like DefaultArgumentPromotion, but
8110	// will create a runtime trap if the resulting type is not a POD type.
8111	ExprResult DefaultVariadicArgumentPromotion(Expr *E, VariadicCallType CT,
8112	FunctionDecl *FDecl);
8113
8114	// Check that the usual arithmetic conversions can be performed on this pair
8115	// of expressions that might be of enumeration type.
8116	void checkEnumArithmeticConversions(Expr LHS, Expr RHS, SourceLocation Loc,
8117	ArithConvKind ACK);
8118
8119	// UsualArithmeticConversions - performs the UsualUnaryConversions on it's
8120	// operands and then handles various conversions that are common to binary
8121	// operators (C99 6.3.1.8). If both operands aren't arithmetic, this
8122	// routine returns the first non-arithmetic type found. The client is
8123	// responsible for emitting appropriate error diagnostics.
8124	QualType UsualArithmeticConversions(ExprResult &LHS, ExprResult &RHS,
8125	SourceLocation Loc, ArithConvKind ACK);
8126
8127	bool IsAssignConvertCompatible(AssignConvertType ConvTy) {
8128	switch (ConvTy) {
8129	default:
8130	return false;
8131	case AssignConvertType::Compatible:
8132	case AssignConvertType::CompatiblePointerDiscardsQualifiers:
8133	case AssignConvertType::CompatibleVoidPtrToNonVoidPtr:
8134	return true;
8135	}
8136	llvm_unreachable("impossible");
8137	}
8138
8139	/// DiagnoseAssignmentResult - Emit a diagnostic, if required, for the
8140	/// assignment conversion type specified by ConvTy. This returns true if the
8141	/// conversion was invalid or false if the conversion was accepted.
8142	bool DiagnoseAssignmentResult(AssignConvertType ConvTy, SourceLocation Loc,
8143	QualType DstType, QualType SrcType,
8144	Expr *SrcExpr, AssignmentAction Action,
8145	bool Complained = nullptr*);
8146
8147	/// CheckAssignmentConstraints - Perform type checking for assignment,
8148	/// argument passing, variable initialization, and function return values.
8149	/// C99 6.5.16.
8150	AssignConvertType CheckAssignmentConstraints(SourceLocation Loc,
8151	QualType LHSType,
8152	QualType RHSType);
8153
8154	/// Check assignment constraints and optionally prepare for a conversion of
8155	/// the RHS to the LHS type. The conversion is prepared for if ConvertRHS
8156	/// is true.
8157	AssignConvertType CheckAssignmentConstraints(QualType LHSType,
8158	ExprResult &RHS, CastKind &Kind,
8159	bool ConvertRHS = true);
8160
8161	/// Check assignment constraints for an assignment of RHS to LHSType.
8162	///
8163	/// \param LHSType The destination type for the assignment.
8164	/// \param RHS The source expression for the assignment.
8165	/// \param Diagnose If \c true, diagnostics may be produced when checking
8166	/// for assignability. If a diagnostic is produced, \p RHS will be
8167	/// set to ExprError(). Note that this function may still return
8168	/// without producing a diagnostic, even for an invalid assignment.
8169	/// \param DiagnoseCFAudited If \c true, the target is a function parameter
8170	/// in an audited Core Foundation API and does not need to be checked
8171	/// for ARC retain issues.
8172	/// \param ConvertRHS If \c true, \p RHS will be updated to model the
8173	/// conversions necessary to perform the assignment. If \c false,
8174	/// \p Diagnose must also be \c false.
8175	AssignConvertType CheckSingleAssignmentConstraints(
8176	QualType LHSType, ExprResult &RHS, bool Diagnose = true,
8177	bool DiagnoseCFAudited = false, bool ConvertRHS = true);
8178
8179	// If the lhs type is a transparent union, check whether we
8180	// can initialize the transparent union with the given expression.
8181	AssignConvertType CheckTransparentUnionArgumentConstraints(QualType ArgType,
8182	ExprResult &RHS);
8183
8184	/// the following "Check" methods will return a valid/converted QualType
8185	/// or a null QualType (indicating an error diagnostic was issued).
8186
8187	/// type checking binary operators (subroutines of CreateBuiltinBinOp).
8188	QualType InvalidOperands(SourceLocation Loc, ExprResult &LHS,
8189	ExprResult &RHS);
8190
8191	/// Diagnose cases where a scalar was implicitly converted to a vector and
8192	/// diagnose the underlying types. Otherwise, diagnose the error
8193	/// as invalid vector logical operands for non-C++ cases.
8194	QualType InvalidLogicalVectorOperands(SourceLocation Loc, ExprResult &LHS,
8195	ExprResult &RHS);
8196
8197	QualType CheckMultiplyDivideOperands( // C99 6.5.5
8198	ExprResult &LHS, ExprResult &RHS, SourceLocation Loc,
8199	BinaryOperatorKind Opc);
8200	QualType CheckRemainderOperands( // C99 6.5.5
8201	ExprResult &LHS, ExprResult &RHS, SourceLocation Loc,
8202	bool IsCompAssign = false);
8203	QualType CheckAdditionOperands( // C99 6.5.6
8204	ExprResult &LHS, ExprResult &RHS, SourceLocation Loc,
8205	BinaryOperatorKind Opc, QualType CompLHSTy = nullptr*);
8206	QualType CheckSubtractionOperands( // C99 6.5.6
8207	ExprResult &LHS, ExprResult &RHS, SourceLocation Loc,
8208	BinaryOperatorKind Opc, QualType CompLHSTy = nullptr*);
8209	QualType CheckShiftOperands( // C99 6.5.7
8210	ExprResult &LHS, ExprResult &RHS, SourceLocation Loc,
8211	BinaryOperatorKind Opc, bool IsCompAssign = false);
8212	void CheckPtrComparisonWithNullChar(ExprResult &E, ExprResult &NullE);
8213	QualType CheckCompareOperands( // C99 6.5.8/9
8214	ExprResult &LHS, ExprResult &RHS, SourceLocation Loc,
8215	BinaryOperatorKind Opc);
8216	QualType CheckBitwiseOperands( // C99 6.5.[10...12]
8217	ExprResult &LHS, ExprResult &RHS, SourceLocation Loc,
8218	BinaryOperatorKind Opc);
8219	QualType CheckLogicalOperands( // C99 6.5.[13,14]
8220	ExprResult &LHS, ExprResult &RHS, SourceLocation Loc,
8221	BinaryOperatorKind Opc);
8222	// CheckAssignmentOperands is used for both simple and compound assignment.
8223	// For simple assignment, pass both expressions and a null converted type.
8224	// For compound assignment, pass both expressions and the converted type.
8225	QualType CheckAssignmentOperands( // C99 6.5.16.[1,2]
8226	Expr *LHSExpr, ExprResult &RHS, SourceLocation Loc, QualType CompoundType,
8227	BinaryOperatorKind Opc);
8228
8229	/// To be used for checking whether the arguments being passed to
8230	/// function exceeds the number of parameters expected for it.
8231	static bool TooManyArguments(size_t NumParams, size_t NumArgs,
8232	bool PartialOverloading = false) {
8233	// We check whether we're just after a comma in code-completion.
8234	if (NumArgs > `0` && PartialOverloading)
8235	return NumArgs + `1` > NumParams; // If so, we view as an extra argument.
8236	return NumArgs > NumParams;
8237	}
8238
8239	/// Whether the AST is currently being rebuilt to correct immediate
8240	/// invocations. Immediate invocation candidates and references to consteval
8241	/// functions aren't tracked when this is set.
8242	bool RebuildingImmediateInvocation = false;
8243
8244	bool isAlwaysConstantEvaluatedContext() const {
8245	const ExpressionEvaluationContextRecord &Ctx = currentEvaluationContext();
8246	return (Ctx.isConstantEvaluated() \|\| isConstantEvaluatedOverride) &&
8247	!Ctx.InConditionallyConstantEvaluateContext;
8248	}
8249
8250	/// Determines whether we are currently in a context that
8251	/// is not evaluated as per C++ [expr] p5.
8252	bool isUnevaluatedContext() const {
8253	return currentEvaluationContext().isUnevaluated();
8254	}
8255
8256	bool isImmediateFunctionContext() const {
8257	return currentEvaluationContext().isImmediateFunctionContext();
8258	}
8259
8260	bool isInLifetimeExtendingContext() const {
8261	return currentEvaluationContext().InLifetimeExtendingContext;
8262	}
8263
8264	bool needsRebuildOfDefaultArgOrInit() const {
8265	return currentEvaluationContext().RebuildDefaultArgOrDefaultInit;
8266	}
8267
8268	bool isCheckingDefaultArgumentOrInitializer() const {
8269	const ExpressionEvaluationContextRecord &Ctx = currentEvaluationContext();
8270	return (Ctx.Context ==
8271	ExpressionEvaluationContext::PotentiallyEvaluatedIfUsed) \|\|
8272	Ctx.IsCurrentlyCheckingDefaultArgumentOrInitializer;
8273	}
8274
8275	std::optional<ExpressionEvaluationContextRecord::InitializationContext>
8276	InnermostDeclarationWithDelayedImmediateInvocations() const {
8277	assert(!ExprEvalContexts.empty() &&
8278	"Must be in an expression evaluation context");
8279	for (const auto &Ctx : llvm::reverse(C: ExprEvalContexts)) {
8280	if (Ctx.Context == ExpressionEvaluationContext::PotentiallyEvaluated &&
8281	Ctx.DelayedDefaultInitializationContext)
8282	return Ctx.DelayedDefaultInitializationContext;
8283	if (Ctx.isConstantEvaluated() \|\| Ctx.isImmediateFunctionContext() \|\|
8284	Ctx.isUnevaluated())
8285	break;
8286	}
8287	return std::nullopt;
8288	}
8289
8290	std::optional<ExpressionEvaluationContextRecord::InitializationContext>
8291	OutermostDeclarationWithDelayedImmediateInvocations() const {
8292	assert(!ExprEvalContexts.empty() &&
8293	"Must be in an expression evaluation context");
8294	std::optional<ExpressionEvaluationContextRecord::InitializationContext> Res;
8295	for (auto &Ctx : llvm::reverse(C: ExprEvalContexts)) {
8296	if (Ctx.Context == ExpressionEvaluationContext::PotentiallyEvaluated &&
8297	!Ctx.DelayedDefaultInitializationContext && Res)
8298	break;
8299	if (Ctx.isConstantEvaluated() \|\| Ctx.isImmediateFunctionContext() \|\|
8300	Ctx.isUnevaluated())
8301	break;
8302	Res = Ctx.DelayedDefaultInitializationContext;
8303	}
8304	return Res;
8305	}
8306
8307	DefaultedComparisonKind getDefaultedComparisonKind(const FunctionDecl *FD) {
8308	return getDefaultedFunctionKind(FD).asComparison();
8309	}
8310
8311	/// Returns a field in a CXXRecordDecl that has the same name as the decl \p
8312	/// SelfAssigned when inside a CXXMethodDecl.
8313	const FieldDecl *
8314	getSelfAssignmentClassMemberCandidate(const ValueDecl *SelfAssigned);
8315
8316	void MaybeSuggestAddingStaticToDecl(const FunctionDecl *D);
8317
8318	template <typename... Ts>
8319	bool RequireCompleteSizedType(SourceLocation Loc, QualType T, unsigned DiagID,
8320	const Ts &...Args) {
8321	SizelessTypeDiagnoser<Ts...> Diagnoser(DiagID, Args...);
8322	return RequireCompleteType(Loc, T, CompleteTypeKind::Normal, Diagnoser);
8323	}
8324
8325	template <typename... Ts>
8326	bool RequireCompleteSizedExprType(Expr E, unsigned* DiagID,
8327	const Ts &...Args) {
8328	SizelessTypeDiagnoser<Ts...> Diagnoser(DiagID, Args...);
8329	return RequireCompleteExprType(E, CompleteTypeKind::Normal, Diagnoser);
8330	}
8331
8332	/// Abstract class used to diagnose incomplete types.
8333	struct TypeDiagnoser {
8334	TypeDiagnoser() {}
8335
8336	virtual void diagnose(Sema &S, SourceLocation Loc, QualType T) = `0`;
8337	virtual ~TypeDiagnoser() {}
8338	};
8339
8340	template <typename... Ts> class BoundTypeDiagnoser : public TypeDiagnoser {
8341	protected:
8342	unsigned DiagID;
8343	std::tuple<const Ts &...> Args;
8344
8345	template <std::size_t... Is>
8346	void emit(const SemaDiagnosticBuilder &DB,
8347	std::index_sequence<Is...>) const {
8348	// Apply all tuple elements to the builder in order.
8349	bool Dummy[] = {false, (DB << getPrintable(std::get<Is>(Args)))...};
8350	(void)Dummy;
8351	}
8352
8353	public:
8354	BoundTypeDiagnoser(unsigned DiagID, const Ts &...Args)
8355	: TypeDiagnoser(), DiagID(DiagID), Args(Args...) {
8356	assert(DiagID != `0` && "no diagnostic for type diagnoser");
8357	}
8358
8359	void diagnose(Sema &S, SourceLocation Loc, QualType T) override {
8360	const SemaDiagnosticBuilder &DB = S.Diag(Loc, DiagID);
8361	emit(DB, std::index_sequence_for<Ts...>());
8362	DB << T;
8363	}
8364	};
8365
8366	/// A derivative of BoundTypeDiagnoser for which the diagnostic's type
8367	/// parameter is preceded by a 0/1 enum that is 1 if the type is sizeless.
8368	/// For example, a diagnostic with no other parameters would generally have
8369	/// the form "...%select{incomplete\|sizeless}0 type %1...".
8370	template <typename... Ts>
8371	class SizelessTypeDiagnoser : public BoundTypeDiagnoser<Ts...> {
8372	public:
8373	SizelessTypeDiagnoser(unsigned DiagID, const Ts &...Args)
8374	: BoundTypeDiagnoser<Ts...>(DiagID, Args...) {}
8375
8376	void diagnose(Sema &S, SourceLocation Loc, QualType T) override {
8377	const SemaDiagnosticBuilder &DB = S.Diag(Loc, this->DiagID);
8378	this->emit(DB, std::index_sequence_for<Ts...>());
8379	DB << T ->isSizelessType() << T;
8380	}
8381	};
8382
8383	/// Check an argument list for placeholders that we won't try to
8384	/// handle later.
8385	bool CheckArgsForPlaceholders(MultiExprArg args);
8386
8387	/// The C++ "std::source_location::__impl" struct, defined in
8388	/// \<source_location>.
8389	RecordDecl *StdSourceLocationImplDecl;
8390
8391	/// A stack of expression evaluation contexts.
8392	SmallVector<ExpressionEvaluationContextRecord, `8`> ExprEvalContexts;
8393
8394	// Set of failed immediate invocations to avoid double diagnosing.
8395	llvm::SmallPtrSet<ConstantExpr *, `4`> FailedImmediateInvocations;
8396
8397	/// List of SourceLocations where 'self' is implicitly retained inside a
8398	/// block.
8399	llvm::SmallVector<std::pair<SourceLocation, const BlockDecl *>, `1`>
8400	ImplicitlyRetainedSelfLocs;
8401
8402	/// Do an explicit extend of the given block pointer if we're in ARC.
8403	void maybeExtendBlockObject(ExprResult &E);
8404
8405	std::vector<std::pair<QualType, unsigned>> ExcessPrecisionNotSatisfied;
8406	SourceLocation LocationOfExcessPrecisionNotSatisfied;
8407	void DiagnosePrecisionLossInComplexDivision();
8408
8409	private:
8410	static BinaryOperatorKind ConvertTokenKindToBinaryOpcode(tok::TokenKind Kind);
8411
8412	/// Methods for marking which expressions involve dereferencing a pointer
8413	/// marked with the 'noderef' attribute. Expressions are checked bottom up as
8414	/// they are parsed, meaning that a noderef pointer may not be accessed. For
8415	/// example, in `&p` where `p` is a noderef pointer, we will first parse the*
8416	/// `p`, but need to check that `address of` is called on it. This requires*
8417	/// keeping a container of all pending expressions and checking if the address
8418	/// of them are eventually taken.
8419	void CheckSubscriptAccessOfNoDeref(const ArraySubscriptExpr *E);
8420	void CheckAddressOfNoDeref(const Expr *E);
8421
8422	///@}
8423
8424	//
8425	//
8426	// -------------------------------------------------------------------------
8427	//
8428	//
8429
8430	/// \name C++ Expressions
8431	/// Implementations are in SemaExprCXX.cpp
8432	///@{
8433
8434	public:
8435	/// The C++ "std::bad_alloc" class, which is defined by the C++
8436	/// standard library.
8437	LazyDeclPtr StdBadAlloc;
8438
8439	/// The C++ "std::align_val_t" enum class, which is defined by the C++
8440	/// standard library.
8441	LazyDeclPtr StdAlignValT;
8442
8443	/// The C++ "type_info" declaration, which is defined in \<typeinfo>.
8444	RecordDecl *CXXTypeInfoDecl;
8445
8446	/// A flag to remember whether the implicit forms of operator new and delete
8447	/// have been declared.
8448	bool GlobalNewDeleteDeclared;
8449
8450	/// Delete-expressions to be analyzed at the end of translation unit
8451	///
8452	/// This list contains class members, and locations of delete-expressions
8453	/// that could not be proven as to whether they mismatch with new-expression
8454	/// used in initializer of the field.
8455	llvm::MapVector<FieldDecl *, DeleteLocs> DeleteExprs;
8456
8457	/// Handle the result of the special case name lookup for inheriting
8458	/// constructor declarations. 'NS::X::X' and 'NS::X<...>::X' are treated as
8459	/// constructor names in member using declarations, even if 'X' is not the
8460	/// name of the corresponding type.
8461	ParsedType getInheritingConstructorName(CXXScopeSpec &SS,
8462	SourceLocation NameLoc,
8463	const IdentifierInfo &Name);
8464
8465	ParsedType getConstructorName(const IdentifierInfo &II,
8466	SourceLocation NameLoc, Scope *S,
8467	CXXScopeSpec &SS, bool EnteringContext);
8468	ParsedType getDestructorName(const IdentifierInfo &II, SourceLocation NameLoc,
8469	Scope *S, CXXScopeSpec &SS,
8470	ParsedType ObjectType, bool EnteringContext);
8471
8472	ParsedType getDestructorTypeForDecltype(const DeclSpec &DS,
8473	ParsedType ObjectType);
8474
8475	/// Build a C++ typeid expression with a type operand.
8476	ExprResult BuildCXXTypeId(QualType TypeInfoType, SourceLocation TypeidLoc,
8477	TypeSourceInfo *Operand, SourceLocation RParenLoc);
8478
8479	/// Build a C++ typeid expression with an expression operand.
8480	ExprResult BuildCXXTypeId(QualType TypeInfoType, SourceLocation TypeidLoc,
8481	Expr *Operand, SourceLocation RParenLoc);
8482
8483	/// ActOnCXXTypeid - Parse typeid( something ).
8484	ExprResult ActOnCXXTypeid(SourceLocation OpLoc, SourceLocation LParenLoc,
8485	bool isType, void *TyOrExpr,
8486	SourceLocation RParenLoc);
8487
8488	/// Build a Microsoft __uuidof expression with a type operand.
8489	ExprResult BuildCXXUuidof(QualType TypeInfoType, SourceLocation TypeidLoc,
8490	TypeSourceInfo *Operand, SourceLocation RParenLoc);
8491
8492	/// Build a Microsoft __uuidof expression with an expression operand.
8493	ExprResult BuildCXXUuidof(QualType TypeInfoType, SourceLocation TypeidLoc,
8494	Expr *Operand, SourceLocation RParenLoc);
8495
8496	/// ActOnCXXUuidof - Parse __uuidof( something ).
8497	ExprResult ActOnCXXUuidof(SourceLocation OpLoc, SourceLocation LParenLoc,
8498	bool isType, void *TyOrExpr,
8499	SourceLocation RParenLoc);
8500
8501	//// ActOnCXXThis - Parse 'this' pointer.
8502	ExprResult ActOnCXXThis(SourceLocation Loc);
8503
8504	/// Check whether the type of 'this' is valid in the current context.
8505	bool CheckCXXThisType(SourceLocation Loc, QualType Type);
8506
8507	/// Build a CXXThisExpr and mark it referenced in the current context.
8508	Expr BuildCXXThisExpr(SourceLocation Loc, QualType Type, bool* IsImplicit);
8509	void MarkThisReferenced(CXXThisExpr *This);
8510
8511	/// Try to retrieve the type of the 'this' pointer.
8512	///
8513	/// \returns The type of 'this', if possible. Otherwise, returns a NULL type.
8514	QualType getCurrentThisType();
8515
8516	/// When non-NULL, the C++ 'this' expression is allowed despite the
8517	/// current context not being a non-static member function. In such cases,
8518	/// this provides the type used for 'this'.
8519	QualType CXXThisTypeOverride;
8520
8521	/// RAII object used to temporarily allow the C++ 'this' expression
8522	/// to be used, with the given qualifiers on the current class type.
8523	class CXXThisScopeRAII {
8524	Sema &S;
8525	QualType OldCXXThisTypeOverride;
8526	bool Enabled;
8527
8528	public:
8529	/// Introduce a new scope where 'this' may be allowed (when enabled),
8530	/// using the given declaration (which is either a class template or a
8531	/// class) along with the given qualifiers.
8532	/// along with the qualifiers placed on 'this'.*
8533	CXXThisScopeRAII(Sema &S, Decl *ContextDecl, Qualifiers CXXThisTypeQuals,
8534	bool Enabled = true);
8535
8536	~CXXThisScopeRAII();
8537	CXXThisScopeRAII(const CXXThisScopeRAII &) = delete;
8538	CXXThisScopeRAII &operator=(const CXXThisScopeRAII &) = delete;
8539	};
8540
8541	/// Make sure the value of 'this' is actually available in the current
8542	/// context, if it is a potentially evaluated context.
8543	///
8544	/// \param Loc The location at which the capture of 'this' occurs.
8545	///
8546	/// \param Explicit Whether 'this' is explicitly captured in a lambda
8547	/// capture list.
8548	///
8549	/// \param FunctionScopeIndexToStopAt If non-null, it points to the index
8550	/// of the FunctionScopeInfo stack beyond which we do not attempt to capture.
8551	/// This is useful when enclosing lambdas must speculatively capture
8552	/// 'this' that may or may not be used in certain specializations of
8553	/// a nested generic lambda (depending on whether the name resolves to
8554	/// a non-static member function or a static function).
8555	/// \return returns 'true' if failed, 'false' if success.
8556	bool CheckCXXThisCapture(
8557	SourceLocation Loc, bool Explicit = false, bool BuildAndDiagnose = true,
8558	const unsigned *const FunctionScopeIndexToStopAt = nullptr,
8559	bool ByCopy = false);
8560
8561	/// Determine whether the given type is the type of this that is used*
8562	/// outside of the body of a member function for a type that is currently
8563	/// being defined.
8564	bool isThisOutsideMemberFunctionBody(QualType BaseType);
8565
8566	/// ActOnCXXBoolLiteral - Parse {true,false} literals.
8567	ExprResult ActOnCXXBoolLiteral(SourceLocation OpLoc, tok::TokenKind Kind);
8568
8569	/// ActOnCXXNullPtrLiteral - Parse 'nullptr'.
8570	ExprResult ActOnCXXNullPtrLiteral(SourceLocation Loc);
8571
8572	//// ActOnCXXThrow - Parse throw expressions.
8573	ExprResult ActOnCXXThrow(Scope S, SourceLocation OpLoc, Expr expr);
8574	ExprResult BuildCXXThrow(SourceLocation OpLoc, Expr *Ex,
8575	bool IsThrownVarInScope);
8576
8577	/// CheckCXXThrowOperand - Validate the operand of a throw.
8578	bool CheckCXXThrowOperand(SourceLocation ThrowLoc, QualType ThrowTy, Expr *E);
8579
8580	/// ActOnCXXTypeConstructExpr - Parse construction of a specified type.
8581	/// Can be interpreted either as function-style casting ("int(x)")
8582	/// or class type construction ("ClassType(x,y,z)")
8583	/// or creation of a value-initialized type ("int()").
8584	ExprResult ActOnCXXTypeConstructExpr(ParsedType TypeRep,
8585	SourceLocation LParenOrBraceLoc,
8586	MultiExprArg Exprs,
8587	SourceLocation RParenOrBraceLoc,
8588	bool ListInitialization);
8589
8590	ExprResult BuildCXXTypeConstructExpr(TypeSourceInfo *Type,
8591	SourceLocation LParenLoc,
8592	MultiExprArg Exprs,
8593	SourceLocation RParenLoc,
8594	bool ListInitialization);
8595
8596	/// Parsed a C++ 'new' expression (C++ 5.3.4).
8597	///
8598	/// E.g.:
8599	/// @code new (memory) int[size][4] @endcode
8600	/// or
8601	/// @code ::new Foo(23, "hello") @endcode
8602	///
8603	/// \param StartLoc The first location of the expression.
8604	/// \param UseGlobal True if 'new' was prefixed with '::'.
8605	/// \param PlacementLParen Opening paren of the placement arguments.
8606	/// \param PlacementArgs Placement new arguments.
8607	/// \param PlacementRParen Closing paren of the placement arguments.
8608	/// \param TypeIdParens If the type is in parens, the source range.
8609	/// \param D The type to be allocated, as well as array dimensions.
8610	/// \param Initializer The initializing expression or initializer-list, or
8611	/// null if there is none.
8612	ExprResult ActOnCXXNew(SourceLocation StartLoc, bool UseGlobal,
8613	SourceLocation PlacementLParen,
8614	MultiExprArg PlacementArgs,
8615	SourceLocation PlacementRParen,
8616	SourceRange TypeIdParens, Declarator &D,
8617	Expr *Initializer);
8618	ExprResult
8619	BuildCXXNew(SourceRange Range, bool UseGlobal, SourceLocation PlacementLParen,
8620	MultiExprArg PlacementArgs, SourceLocation PlacementRParen,
8621	SourceRange TypeIdParens, QualType AllocType,
8622	TypeSourceInfo AllocTypeInfo, std::optional<Expr > ArraySize,
8623	SourceRange DirectInitRange, Expr *Initializer);
8624
8625	/// Determine whether \p FD is an aligned allocation or deallocation
8626	/// function that is unavailable.
8627	bool isUnavailableAlignedAllocationFunction(const FunctionDecl &FD) const;
8628
8629	/// Produce diagnostics if \p FD is an aligned allocation or deallocation
8630	/// function that is unavailable.
8631	void diagnoseUnavailableAlignedAllocation(const FunctionDecl &FD,
8632	SourceLocation Loc);
8633
8634	/// Checks that a type is suitable as the allocated type
8635	/// in a new-expression.
8636	bool CheckAllocatedType(QualType AllocType, SourceLocation Loc,
8637	SourceRange R);
8638
8639	/// Finds the overloads of operator new and delete that are appropriate
8640	/// for the allocation.
8641	bool FindAllocationFunctions(
8642	SourceLocation StartLoc, SourceRange Range,
8643	AllocationFunctionScope NewScope, AllocationFunctionScope DeleteScope,
8644	QualType AllocType, bool IsArray, ImplicitAllocationParameters &IAP,
8645	MultiExprArg PlaceArgs, FunctionDecl *&OperatorNew,
8646	FunctionDecl &OperatorDelete, bool* Diagnose = true);
8647
8648	/// DeclareGlobalNewDelete - Declare the global forms of operator new and
8649	/// delete. These are:
8650	/// @code
8651	/// // C++03:
8652	/// void operator new(std::size_t) throw(std::bad_alloc);*
8653	/// void operator new[](std::size_t) throw(std::bad_alloc);*
8654	/// void operator delete(void ) throw();*
8655	/// void operator delete[](void ) throw();*
8656	/// // C++11:
8657	/// void operator new(std::size_t);*
8658	/// void operator new[](std::size_t);*
8659	/// void operator delete(void ) noexcept;*
8660	/// void operator delete[](void ) noexcept;*
8661	/// // C++1y:
8662	/// void operator new(std::size_t);*
8663	/// void operator new[](std::size_t);*
8664	/// void operator delete(void ) noexcept;*
8665	/// void operator delete[](void ) noexcept;*
8666	/// void operator delete(void , std::size_t) noexcept;*
8667	/// void operator delete[](void , std::size_t) noexcept;*
8668	/// @endcode
8669	/// Note that the placement and nothrow forms of new are not* implicitly*
8670	/// declared. Their use requires including \<new\>.
8671	void DeclareGlobalNewDelete();
8672	void DeclareGlobalAllocationFunction(DeclarationName Name, QualType Return,
8673	ArrayRef<QualType> Params);
8674
8675	bool FindDeallocationFunction(SourceLocation StartLoc, CXXRecordDecl *RD,
8676	DeclarationName Name, FunctionDecl *&Operator,
8677	ImplicitDeallocationParameters,
8678	bool Diagnose = true);
8679	FunctionDecl *FindUsualDeallocationFunction(SourceLocation StartLoc,
8680	ImplicitDeallocationParameters,
8681	DeclarationName Name,
8682	bool Diagnose = true);
8683	FunctionDecl *FindDeallocationFunctionForDestructor(SourceLocation StartLoc,
8684	CXXRecordDecl *RD,
8685	bool Diagnose,
8686	bool LookForGlobal,
8687	DeclarationName Name);
8688
8689	/// ActOnCXXDelete - Parsed a C++ 'delete' expression (C++ 5.3.5), as in:
8690	/// @code ::delete ptr; @endcode
8691	/// or
8692	/// @code delete [] ptr; @endcode
8693	ExprResult ActOnCXXDelete(SourceLocation StartLoc, bool UseGlobal,
8694	bool ArrayForm, Expr *Operand);
8695	void CheckVirtualDtorCall(CXXDestructorDecl *dtor, SourceLocation Loc,
8696	bool IsDelete, bool CallCanBeVirtual,
8697	bool WarnOnNonAbstractTypes,
8698	SourceLocation DtorLoc);
8699
8700	ExprResult ActOnNoexceptExpr(SourceLocation KeyLoc, SourceLocation LParen,
8701	Expr *Operand, SourceLocation RParen);
8702	ExprResult BuildCXXNoexceptExpr(SourceLocation KeyLoc, Expr *Operand,
8703	SourceLocation RParen);
8704
8705	ExprResult ActOnStartCXXMemberReference(Scope S, Expr Base,
8706	SourceLocation OpLoc,
8707	tok::TokenKind OpKind,
8708	ParsedType &ObjectType,
8709	bool &MayBePseudoDestructor);
8710
8711	ExprResult BuildPseudoDestructorExpr(
8712	Expr *Base, SourceLocation OpLoc, tok::TokenKind OpKind,
8713	const CXXScopeSpec &SS, TypeSourceInfo *ScopeType, SourceLocation CCLoc,
8714	SourceLocation TildeLoc, PseudoDestructorTypeStorage DestroyedType);
8715
8716	ExprResult ActOnPseudoDestructorExpr(
8717	Scope S, Expr Base, SourceLocation OpLoc, tok::TokenKind OpKind,
8718	CXXScopeSpec &SS, UnqualifiedId &FirstTypeName, SourceLocation CCLoc,
8719	SourceLocation TildeLoc, UnqualifiedId &SecondTypeName);
8720
8721	ExprResult ActOnPseudoDestructorExpr(Scope S, Expr Base,
8722	SourceLocation OpLoc,
8723	tok::TokenKind OpKind,
8724	SourceLocation TildeLoc,
8725	const DeclSpec &DS);
8726
8727	/// MaybeCreateExprWithCleanups - If the current full-expression
8728	/// requires any cleanups, surround it with a ExprWithCleanups node.
8729	/// Otherwise, just returns the passed-in expression.
8730	Expr MaybeCreateExprWithCleanups(Expr SubExpr);
8731	Stmt MaybeCreateStmtWithCleanups(Stmt SubStmt);
8732	ExprResult MaybeCreateExprWithCleanups(ExprResult SubExpr);
8733
8734	ExprResult ActOnFinishFullExpr(Expr Expr, bool* DiscardedValue) {
8735	return ActOnFinishFullExpr(
8736	Expr, CC: Expr ? Expr->getExprLoc() : SourceLocation (), DiscardedValue);
8737	}
8738	ExprResult ActOnFinishFullExpr(Expr *Expr, SourceLocation CC,
8739	bool DiscardedValue, bool IsConstexpr = false,
8740	bool IsTemplateArgument = false);
8741	StmtResult ActOnFinishFullStmt(Stmt *Stmt);
8742
8743	/// Process the expression contained within a decltype. For such expressions,
8744	/// certain semantic checks on temporaries are delayed until this point, and
8745	/// are omitted for the 'topmost' call in the decltype expression. If the
8746	/// topmost call bound a temporary, strip that temporary off the expression.
8747	ExprResult ActOnDecltypeExpression(Expr *E);
8748
8749	bool checkLiteralOperatorId(const CXXScopeSpec &SS, const UnqualifiedId &Id,
8750	bool IsUDSuffix);
8751
8752	bool isUsualDeallocationFunction(const CXXMethodDecl *FD);
8753
8754	ConditionResult ActOnConditionVariable(Decl *ConditionVar,
8755	SourceLocation StmtLoc,
8756	ConditionKind CK);
8757
8758	/// Check the use of the given variable as a C++ condition in an if,
8759	/// while, do-while, or switch statement.
8760	ExprResult CheckConditionVariable(VarDecl *ConditionVar,
8761	SourceLocation StmtLoc, ConditionKind CK);
8762
8763	/// CheckCXXBooleanCondition - Returns true if conversion to bool is invalid.
8764	ExprResult CheckCXXBooleanCondition(Expr CondExpr, bool* IsConstexpr = false);
8765
8766	/// Helper function to determine whether this is the (deprecated) C++
8767	/// conversion from a string literal to a pointer to non-const char or
8768	/// non-const wchar_t (for narrow and wide string literals,
8769	/// respectively).
8770	bool IsStringLiteralToNonConstPointerConversion(Expr *From, QualType ToType);
8771
8772	/// PerformImplicitConversion - Perform an implicit conversion of the
8773	/// expression From to the type ToType using the pre-computed implicit
8774	/// conversion sequence ICS. Returns the converted
8775	/// expression. Action is the kind of conversion we're performing,
8776	/// used in the error message.
8777	ExprResult PerformImplicitConversion(
8778	Expr From, QualType ToType, const* ImplicitConversionSequence &ICS,
8779	AssignmentAction Action,
8780	CheckedConversionKind CCK = CheckedConversionKind::Implicit);
8781
8782	/// PerformImplicitConversion - Perform an implicit conversion of the
8783	/// expression From to the type ToType by following the standard
8784	/// conversion sequence SCS. Returns the converted
8785	/// expression. Flavor is the context in which we're performing this
8786	/// conversion, for use in error messages.
8787	ExprResult PerformImplicitConversion(Expr *From, QualType ToType,
8788	const StandardConversionSequence &SCS,
8789	AssignmentAction Action,
8790	CheckedConversionKind CCK);
8791
8792	bool CheckTypeTraitArity(unsigned Arity, SourceLocation Loc, size_t N);
8793
8794	/// Parsed one of the type trait support pseudo-functions.
8795	ExprResult ActOnTypeTrait(TypeTrait Kind, SourceLocation KWLoc,
8796	ArrayRef<ParsedType> Args,
8797	SourceLocation RParenLoc);
8798	ExprResult BuildTypeTrait(TypeTrait Kind, SourceLocation KWLoc,
8799	ArrayRef<TypeSourceInfo *> Args,
8800	SourceLocation RParenLoc);
8801
8802	/// ActOnArrayTypeTrait - Parsed one of the binary type trait support
8803	/// pseudo-functions.
8804	ExprResult ActOnArrayTypeTrait(ArrayTypeTrait ATT, SourceLocation KWLoc,
8805	ParsedType LhsTy, Expr *DimExpr,
8806	SourceLocation RParen);
8807
8808	ExprResult BuildArrayTypeTrait(ArrayTypeTrait ATT, SourceLocation KWLoc,
8809	TypeSourceInfo TSInfo, Expr DimExpr,
8810	SourceLocation RParen);
8811
8812	/// ActOnExpressionTrait - Parsed one of the unary type trait support
8813	/// pseudo-functions.
8814	ExprResult ActOnExpressionTrait(ExpressionTrait OET, SourceLocation KWLoc,
8815	Expr *Queried, SourceLocation RParen);
8816
8817	ExprResult BuildExpressionTrait(ExpressionTrait OET, SourceLocation KWLoc,
8818	Expr *Queried, SourceLocation RParen);
8819
8820	QualType CheckPointerToMemberOperands( // C++ 5.5
8821	ExprResult &LHS, ExprResult &RHS, ExprValueKind &VK, SourceLocation OpLoc,
8822	bool isIndirect);
8823	QualType CheckVectorConditionalTypes(ExprResult &Cond, ExprResult &LHS,
8824	ExprResult &RHS,
8825	SourceLocation QuestionLoc);
8826
8827	//// Determines if a type is trivially relocatable
8828	/// according to the C++26 rules.
8829	// FIXME: This is in Sema because it requires
8830	// overload resolution, can we move to ASTContext?
8831	bool IsCXXTriviallyRelocatableType(QualType T);
8832	bool IsCXXTriviallyRelocatableType(const CXXRecordDecl &RD);
8833
8834	/// Check the operands of ?: under C++ semantics.
8835	///
8836	/// See C++ [expr.cond]. Note that LHS is never null, even for the GNU x ?: y
8837	/// extension. In this case, LHS == Cond. (But they're not aliases.)
8838	///
8839	/// This function also implements GCC's vector extension and the
8840	/// OpenCL/ext_vector_type extension for conditionals. The vector extensions
8841	/// permit the use of a?b:c where the type of a is that of a integer vector
8842	/// with the same number of elements and size as the vectors of b and c. If
8843	/// one of either b or c is a scalar it is implicitly converted to match the
8844	/// type of the vector. Otherwise the expression is ill-formed. If both b and
8845	/// c are scalars, then b and c are checked and converted to the type of a if
8846	/// possible.
8847	///
8848	/// The expressions are evaluated differently for GCC's and OpenCL's
8849	/// extensions. For the GCC extension, the ?: operator is evaluated as
8850	/// (a[0] != 0 ? b[0] : c[0], .. , a[n] != 0 ? b[n] : c[n]).
8851	/// For the OpenCL extensions, the ?: operator is evaluated as
8852	/// (most-significant-bit-set(a[0]) ? b[0] : c[0], .. ,
8853	/// most-significant-bit-set(a[n]) ? b[n] : c[n]).
8854	QualType CXXCheckConditionalOperands( // C++ 5.16
8855	ExprResult &cond, ExprResult &lhs, ExprResult &rhs, ExprValueKind &VK,
8856	ExprObjectKind &OK, SourceLocation questionLoc);
8857
8858	/// Find a merged pointer type and convert the two expressions to it.
8859	///
8860	/// This finds the composite pointer type for \p E1 and \p E2 according to
8861	/// C++2a [expr.type]p3. It converts both expressions to this type and returns
8862	/// it. It does not emit diagnostics (FIXME: that's not true if \p
8863	/// ConvertArgs is \c true).
8864	///
8865	/// \param Loc The location of the operator requiring these two expressions to
8866	/// be converted to the composite pointer type.
8867	///
8868	/// \param ConvertArgs If \c false, do not convert E1 and E2 to the target
8869	/// type.
8870	QualType FindCompositePointerType(SourceLocation Loc, Expr &E1, Expr &E2,
8871	bool ConvertArgs = true);
8872	QualType FindCompositePointerType(SourceLocation Loc, ExprResult &E1,
8873	ExprResult &E2, bool ConvertArgs = true) {
8874	Expr E1Tmp = E1.get(), E2Tmp = E2.get();
8875	QualType Composite =
8876	FindCompositePointerType(Loc, E1&: E1Tmp, E2&: E2Tmp, ConvertArgs);
8877	E1 = E1Tmp;
8878	E2 = E2Tmp;
8879	return Composite;
8880	}
8881
8882	/// MaybeBindToTemporary - If the passed in expression has a record type with
8883	/// a non-trivial destructor, this will return CXXBindTemporaryExpr. Otherwise
8884	/// it simply returns the passed in expression.
8885	ExprResult MaybeBindToTemporary(Expr *E);
8886
8887	/// IgnoredValueConversions - Given that an expression's result is
8888	/// syntactically ignored, perform any conversions that are
8889	/// required.
8890	ExprResult IgnoredValueConversions(Expr *E);
8891
8892	ExprResult CheckUnevaluatedOperand(Expr *E);
8893
8894	IfExistsResult
8895	CheckMicrosoftIfExistsSymbol(Scope *S, CXXScopeSpec &SS,
8896	const DeclarationNameInfo &TargetNameInfo);
8897
8898	IfExistsResult CheckMicrosoftIfExistsSymbol(Scope *S,
8899	SourceLocation KeywordLoc,
8900	bool IsIfExists, CXXScopeSpec &SS,
8901	UnqualifiedId &Name);
8902
8903	RequiresExprBodyDecl *
8904	ActOnStartRequiresExpr(SourceLocation RequiresKWLoc,
8905	ArrayRef<ParmVarDecl *> LocalParameters,
8906	Scope *BodyScope);
8907	void ActOnFinishRequiresExpr();
8908	concepts::Requirement ActOnSimpleRequirement(Expr E);
8909	concepts::Requirement *ActOnTypeRequirement(SourceLocation TypenameKWLoc,
8910	CXXScopeSpec &SS,
8911	SourceLocation NameLoc,
8912	const IdentifierInfo *TypeName,
8913	TemplateIdAnnotation *TemplateId);
8914	concepts::Requirement ActOnCompoundRequirement(Expr E,
8915	SourceLocation NoexceptLoc);
8916	concepts::Requirement *ActOnCompoundRequirement(
8917	Expr *E, SourceLocation NoexceptLoc, CXXScopeSpec &SS,
8918	TemplateIdAnnotation TypeConstraint, unsigned* Depth);
8919	concepts::Requirement ActOnNestedRequirement(Expr Constraint);
8920	concepts::ExprRequirement *BuildExprRequirement(
8921	Expr E, bool* IsSatisfied, SourceLocation NoexceptLoc,
8922	concepts::ExprRequirement::ReturnTypeRequirement ReturnTypeRequirement);
8923	concepts::ExprRequirement *BuildExprRequirement(
8924	concepts::Requirement::SubstitutionDiagnostic *ExprSubstDiag,
8925	bool IsSatisfied, SourceLocation NoexceptLoc,
8926	concepts::ExprRequirement::ReturnTypeRequirement ReturnTypeRequirement);
8927	concepts::TypeRequirement BuildTypeRequirement(TypeSourceInfo Type);
8928	concepts::TypeRequirement *BuildTypeRequirement(
8929	concepts::Requirement::SubstitutionDiagnostic *SubstDiag);
8930	concepts::NestedRequirement BuildNestedRequirement(Expr E);
8931	concepts::NestedRequirement *
8932	BuildNestedRequirement(StringRef InvalidConstraintEntity,
8933	const ASTConstraintSatisfaction &Satisfaction);
8934	ExprResult ActOnRequiresExpr(SourceLocation RequiresKWLoc,
8935	RequiresExprBodyDecl *Body,
8936	SourceLocation LParenLoc,
8937	ArrayRef<ParmVarDecl *> LocalParameters,
8938	SourceLocation RParenLoc,
8939	ArrayRef<concepts::Requirement *> Requirements,
8940	SourceLocation ClosingBraceLoc);
8941
8942	private:
8943	ExprResult BuiltinOperatorNewDeleteOverloaded(ExprResult TheCallResult,
8944	bool IsDelete);
8945
8946	void AnalyzeDeleteExprMismatch(const CXXDeleteExpr *DE);
8947	void AnalyzeDeleteExprMismatch(FieldDecl *Field, SourceLocation DeleteLoc,
8948	bool DeleteWasArrayForm);
8949
8950	///@}
8951
8952	//
8953	//
8954	// -------------------------------------------------------------------------
8955	//
8956	//
8957
8958	/// \name Member Access Expressions
8959	/// Implementations are in SemaExprMember.cpp
8960	///@{
8961
8962	public:
8963	/// Check whether an expression might be an implicit class member access.
8964	bool isPotentialImplicitMemberAccess(const CXXScopeSpec &SS, LookupResult &R,
8965	bool IsAddressOfOperand);
8966
8967	/// Builds an expression which might be an implicit member expression.
8968	ExprResult BuildPossibleImplicitMemberExpr(
8969	const CXXScopeSpec &SS, SourceLocation TemplateKWLoc, LookupResult &R,
8970	const TemplateArgumentListInfo TemplateArgs, const* Scope *S);
8971
8972	/// Builds an implicit member access expression. The current context
8973	/// is known to be an instance method, and the given unqualified lookup
8974	/// set is known to contain only instance members, at least one of which
8975	/// is from an appropriate type.
8976	ExprResult
8977	BuildImplicitMemberExpr(const CXXScopeSpec &SS, SourceLocation TemplateKWLoc,
8978	LookupResult &R,
8979	const TemplateArgumentListInfo *TemplateArgs,
8980	bool IsDefiniteInstance, const Scope *S);
8981
8982	ExprResult ActOnDependentMemberExpr(
8983	Expr Base, QualType BaseType, bool* IsArrow, SourceLocation OpLoc,
8984	const CXXScopeSpec &SS, SourceLocation TemplateKWLoc,
8985	NamedDecl FirstQualifierInScope, const* DeclarationNameInfo &NameInfo,
8986	const TemplateArgumentListInfo *TemplateArgs);
8987
8988	/// The main callback when the parser finds something like
8989	/// expression . [nested-name-specifier] identifier
8990	/// expression -> [nested-name-specifier] identifier
8991	/// where 'identifier' encompasses a fairly broad spectrum of
8992	/// possibilities, including destructor and operator references.
8993	///
8994	/// \param OpKind either tok::arrow or tok::period
8995	/// \param ObjCImpDecl the current Objective-C \@implementation
8996	/// decl; this is an ugly hack around the fact that Objective-C
8997	/// \@implementations aren't properly put in the context chain
8998	ExprResult ActOnMemberAccessExpr(Scope S, Expr Base, SourceLocation OpLoc,
8999	tok::TokenKind OpKind, CXXScopeSpec &SS,
9000	SourceLocation TemplateKWLoc,
9001	UnqualifiedId &Member, Decl *ObjCImpDecl);
9002
9003	MemberExpr *
9004	BuildMemberExpr(Expr Base, bool* IsArrow, SourceLocation OpLoc,
9005	NestedNameSpecifierLoc NNS, SourceLocation TemplateKWLoc,
9006	ValueDecl *Member, DeclAccessPair FoundDecl,
9007	bool HadMultipleCandidates,
9008	const DeclarationNameInfo &MemberNameInfo, QualType Ty,
9009	ExprValueKind VK, ExprObjectKind OK,
9010	const TemplateArgumentListInfo TemplateArgs = nullptr*);
9011
9012	// Check whether the declarations we found through a nested-name
9013	// specifier in a member expression are actually members of the base
9014	// type. The restriction here is:
9015	//
9016	// C++ [expr.ref]p2:
9017	// ... In these cases, the id-expression shall name a
9018	// member of the class or of one of its base classes.
9019	//
9020	// So it's perfectly legitimate for the nested-name specifier to name
9021	// an unrelated class, and for us to find an overload set including
9022	// decls from classes which are not superclasses, as long as the decl
9023	// we actually pick through overload resolution is from a superclass.
9024	bool CheckQualifiedMemberReference(Expr *BaseExpr, QualType BaseType,
9025	const CXXScopeSpec &SS,
9026	const LookupResult &R);
9027
9028	// This struct is for use by ActOnMemberAccess to allow
9029	// BuildMemberReferenceExpr to be able to reinvoke ActOnMemberAccess after
9030	// changing the access operator from a '.' to a '->' (to see if that is the
9031	// change needed to fix an error about an unknown member, e.g. when the class
9032	// defines a custom operator->).
9033	struct ActOnMemberAccessExtraArgs {
9034	Scope *S;
9035	UnqualifiedId &Id;
9036	Decl *ObjCImpDecl;
9037	};
9038
9039	ExprResult BuildMemberReferenceExpr(
9040	Expr Base, QualType BaseType, SourceLocation OpLoc, bool* IsArrow,
9041	CXXScopeSpec &SS, SourceLocation TemplateKWLoc,
9042	NamedDecl FirstQualifierInScope, const* DeclarationNameInfo &NameInfo,
9043	const TemplateArgumentListInfo TemplateArgs, const* Scope *S,
9044	ActOnMemberAccessExtraArgs ExtraArgs = nullptr*);
9045
9046	ExprResult
9047	BuildMemberReferenceExpr(Expr *Base, QualType BaseType, SourceLocation OpLoc,
9048	bool IsArrow, const CXXScopeSpec &SS,
9049	SourceLocation TemplateKWLoc,
9050	NamedDecl *FirstQualifierInScope, LookupResult &R,
9051	const TemplateArgumentListInfo *TemplateArgs,
9052	const Scope S, bool* SuppressQualifierCheck = false,
9053	ActOnMemberAccessExtraArgs ExtraArgs = nullptr*);
9054
9055	ExprResult BuildFieldReferenceExpr(Expr BaseExpr, bool* IsArrow,
9056	SourceLocation OpLoc,
9057	const CXXScopeSpec &SS, FieldDecl *Field,
9058	DeclAccessPair FoundDecl,
9059	const DeclarationNameInfo &MemberNameInfo);
9060
9061	/// Perform conversions on the LHS of a member access expression.
9062	ExprResult PerformMemberExprBaseConversion(Expr Base, bool* IsArrow);
9063
9064	ExprResult BuildAnonymousStructUnionMemberReference(
9065	const CXXScopeSpec &SS, SourceLocation nameLoc,
9066	IndirectFieldDecl *indirectField,
9067	DeclAccessPair FoundDecl = DeclAccessPair::make(D: nullptr, AS: AS_none),
9068	Expr baseObjectExpr = nullptr*, SourceLocation opLoc = SourceLocation ());
9069
9070	private:
9071	void CheckMemberAccessOfNoDeref(const MemberExpr *E);
9072
9073	///@}
9074
9075	//
9076	//
9077	// -------------------------------------------------------------------------
9078	//
9079	//
9080
9081	/// \name Initializers
9082	/// Implementations are in SemaInit.cpp
9083	///@{
9084
9085	public:
9086	/// Stack of types that correspond to the parameter entities that are
9087	/// currently being copy-initialized. Can be empty.
9088	llvm::SmallVector<QualType, `4`> CurrentParameterCopyTypes;
9089
9090	llvm::DenseMap<unsigned, CXXDeductionGuideDecl *>
9091	AggregateDeductionCandidates;
9092
9093	bool IsStringInit(Expr Init, const* ArrayType *AT);
9094
9095	/// Determine whether we can perform aggregate initialization for the purposes
9096	/// of overload resolution.
9097	bool CanPerformAggregateInitializationForOverloadResolution(
9098	const InitializedEntity &Entity, InitListExpr *From);
9099
9100	ExprResult ActOnDesignatedInitializer(Designation &Desig,
9101	SourceLocation EqualOrColonLoc,
9102	bool GNUSyntax, ExprResult Init);
9103
9104	/// Check that the lifetime of the initializer (and its subobjects) is
9105	/// sufficient for initializing the entity, and perform lifetime extension
9106	/// (when permitted) if not.
9107	void checkInitializerLifetime(const InitializedEntity &Entity, Expr *Init);
9108
9109	MaterializeTemporaryExpr *
9110	CreateMaterializeTemporaryExpr(QualType T, Expr *Temporary,
9111	bool BoundToLvalueReference);
9112
9113	/// If \p E is a prvalue denoting an unmaterialized temporary, materialize
9114	/// it as an xvalue. In C++98, the result will still be a prvalue, because
9115	/// we don't have xvalues there.
9116	ExprResult TemporaryMaterializationConversion(Expr *E);
9117
9118	ExprResult PerformQualificationConversion(
9119	Expr *E, QualType Ty, ExprValueKind VK = VK_PRValue,
9120	CheckedConversionKind CCK = CheckedConversionKind::Implicit);
9121
9122	bool CanPerformCopyInitialization(const InitializedEntity &Entity,
9123	ExprResult Init);
9124	ExprResult PerformCopyInitialization(const InitializedEntity &Entity,
9125	SourceLocation EqualLoc, ExprResult Init,
9126	bool TopLevelOfInitList = false,
9127	bool AllowExplicit = false);
9128
9129	QualType DeduceTemplateSpecializationFromInitializer(
9130	TypeSourceInfo TInfo, const* InitializedEntity &Entity,
9131	const InitializationKind &Kind, MultiExprArg Init);
9132
9133	///@}
9134
9135	//
9136	//
9137	// -------------------------------------------------------------------------
9138	//
9139	//
9140
9141	/// \name C++ Lambda Expressions
9142	/// Implementations are in SemaLambda.cpp
9143	///@{
9144
9145	public:
9146	/// Create a new lambda closure type.
9147	CXXRecordDecl *createLambdaClosureType(SourceRange IntroducerRange,
9148	TypeSourceInfo *Info,
9149	unsigned LambdaDependencyKind,
9150	LambdaCaptureDefault CaptureDefault);
9151
9152	/// Number lambda for linkage purposes if necessary.
9153	void handleLambdaNumbering(CXXRecordDecl Class, CXXMethodDecl Method,
9154	std::optional<CXXRecordDecl::LambdaNumbering>
9155	NumberingOverride = std::nullopt);
9156
9157	/// Endow the lambda scope info with the relevant properties.
9158	void buildLambdaScope(sema::LambdaScopeInfo LSI, CXXMethodDecl CallOperator,
9159	SourceRange IntroducerRange,
9160	LambdaCaptureDefault CaptureDefault,
9161	SourceLocation CaptureDefaultLoc, bool ExplicitParams,
9162	bool Mutable);
9163
9164	CXXMethodDecl *CreateLambdaCallOperator(SourceRange IntroducerRange,
9165	CXXRecordDecl *Class);
9166
9167	void AddTemplateParametersToLambdaCallOperator(
9168	CXXMethodDecl CallOperator, CXXRecordDecl Class,
9169	TemplateParameterList *TemplateParams);
9170
9171	void
9172	CompleteLambdaCallOperator(CXXMethodDecl *Method, SourceLocation LambdaLoc,
9173	SourceLocation CallOperatorLoc,
9174	const AssociatedConstraint &TrailingRequiresClause,
9175	TypeSourceInfo *MethodTyInfo,
9176	ConstexprSpecKind ConstexprKind, StorageClass SC,
9177	ArrayRef<ParmVarDecl *> Params,
9178	bool HasExplicitResultType);
9179
9180	/// Returns true if the explicit object parameter was invalid.
9181	bool DiagnoseInvalidExplicitObjectParameterInLambda(CXXMethodDecl *Method,
9182	SourceLocation CallLoc);
9183
9184	/// Perform initialization analysis of the init-capture and perform
9185	/// any implicit conversions such as an lvalue-to-rvalue conversion if
9186	/// not being used to initialize a reference.
9187	ParsedType actOnLambdaInitCaptureInitialization(
9188	SourceLocation Loc, bool ByRef, SourceLocation EllipsisLoc,
9189	IdentifierInfo Id, LambdaCaptureInitKind InitKind, Expr &Init) {
9190	return ParsedType::make(P: buildLambdaInitCaptureInitialization(
9191	Loc, ByRef, EllipsisLoc, NumExpansions: std::nullopt, Id,
9192	DirectInit: InitKind != LambdaCaptureInitKind::CopyInit, Init));
9193	}
9194	QualType buildLambdaInitCaptureInitialization(SourceLocation Loc, bool ByRef,
9195	SourceLocation EllipsisLoc,
9196	UnsignedOrNone NumExpansions,
9197	IdentifierInfo *Id,
9198	bool DirectInit, Expr *&Init);
9199
9200	/// Create a dummy variable within the declcontext of the lambda's
9201	/// call operator, for name lookup purposes for a lambda init capture.
9202	///
9203	/// CodeGen handles emission of lambda captures, ignoring these dummy
9204	/// variables appropriately.
9205	VarDecl *createLambdaInitCaptureVarDecl(
9206	SourceLocation Loc, QualType InitCaptureType, SourceLocation EllipsisLoc,
9207	IdentifierInfo Id, unsigned* InitStyle, Expr Init, DeclContext DeclCtx);
9208
9209	/// Add an init-capture to a lambda scope.
9210	void addInitCapture(sema::LambdaScopeInfo LSI, VarDecl Var, bool ByRef);
9211
9212	/// Note that we have finished the explicit captures for the
9213	/// given lambda.
9214	void finishLambdaExplicitCaptures(sema::LambdaScopeInfo *LSI);
9215
9216	/// Deduce a block or lambda's return type based on the return
9217	/// statements present in the body.
9218	void deduceClosureReturnType(sema::CapturingScopeInfo &CSI);
9219
9220	/// Once the Lambdas capture are known, we can start to create the closure,
9221	/// call operator method, and keep track of the captures.
9222	/// We do the capture lookup here, but they are not actually captured until
9223	/// after we know what the qualifiers of the call operator are.
9224	void ActOnLambdaExpressionAfterIntroducer(LambdaIntroducer &Intro,
9225	Scope *CurContext);
9226
9227	/// This is called after parsing the explicit template parameter list
9228	/// on a lambda (if it exists) in C++2a.
9229	void ActOnLambdaExplicitTemplateParameterList(LambdaIntroducer &Intro,
9230	SourceLocation LAngleLoc,
9231	ArrayRef<NamedDecl *> TParams,
9232	SourceLocation RAngleLoc,
9233	ExprResult RequiresClause);
9234
9235	void ActOnLambdaClosureQualifiers(LambdaIntroducer &Intro,
9236	SourceLocation MutableLoc);
9237
9238	void ActOnLambdaClosureParameters(
9239	Scope *LambdaScope,
9240	MutableArrayRef<DeclaratorChunk::ParamInfo> ParamInfo);
9241
9242	/// ActOnStartOfLambdaDefinition - This is called just before we start
9243	/// parsing the body of a lambda; it analyzes the explicit captures and
9244	/// arguments, and sets up various data-structures for the body of the
9245	/// lambda.
9246	void ActOnStartOfLambdaDefinition(LambdaIntroducer &Intro,
9247	Declarator &ParamInfo, const DeclSpec &DS);
9248
9249	/// ActOnLambdaError - If there is an error parsing a lambda, this callback
9250	/// is invoked to pop the information about the lambda.
9251	void ActOnLambdaError(SourceLocation StartLoc, Scope *CurScope,
9252	bool IsInstantiation = false);
9253
9254	/// ActOnLambdaExpr - This is called when the body of a lambda expression
9255	/// was successfully completed.
9256	ExprResult ActOnLambdaExpr(SourceLocation StartLoc, Stmt *Body);
9257
9258	/// Does copying/destroying the captured variable have side effects?
9259	bool CaptureHasSideEffects(const sema::Capture &From);
9260
9261	/// Diagnose if an explicit lambda capture is unused. Returns true if a
9262	/// diagnostic is emitted.
9263	bool DiagnoseUnusedLambdaCapture(SourceRange CaptureRange,
9264	SourceRange FixItRange,
9265	const sema::Capture &From);
9266
9267	/// Build a FieldDecl suitable to hold the given capture.
9268	FieldDecl BuildCaptureField(RecordDecl RD, const sema::Capture &Capture);
9269
9270	/// Initialize the given capture with a suitable expression.
9271	ExprResult BuildCaptureInit(const sema::Capture &Capture,
9272	SourceLocation ImplicitCaptureLoc,
9273	bool IsOpenMPMapping = false);
9274
9275	/// Complete a lambda-expression having processed and attached the
9276	/// lambda body.
9277	ExprResult BuildLambdaExpr(SourceLocation StartLoc, SourceLocation EndLoc);
9278
9279	/// Get the return type to use for a lambda's conversion function(s) to
9280	/// function pointer type, given the type of the call operator.
9281	QualType
9282	getLambdaConversionFunctionResultType(const FunctionProtoType *CallOpType,
9283	CallingConv CC);
9284
9285	ExprResult BuildBlockForLambdaConversion(SourceLocation CurrentLocation,
9286	SourceLocation ConvLocation,
9287	CXXConversionDecl Conv, Expr Src);
9288
9289	class LambdaScopeForCallOperatorInstantiationRAII
9290	: private FunctionScopeRAII {
9291	public:
9292	LambdaScopeForCallOperatorInstantiationRAII(
9293	Sema &SemasRef, FunctionDecl *FD, MultiLevelTemplateArgumentList MLTAL,
9294	LocalInstantiationScope &Scope,
9295	bool ShouldAddDeclsFromParentScope = true);
9296	};
9297
9298	/// Compute the mangling number context for a lambda expression or
9299	/// block literal. Also return the extra mangling decl if any.
9300	///
9301	/// \param DC - The DeclContext containing the lambda expression or
9302	/// block literal.
9303	std::tuple<MangleNumberingContext , Decl >
9304	getCurrentMangleNumberContext(const DeclContext *DC);
9305
9306	///@}
9307
9308	//
9309	//
9310	// -------------------------------------------------------------------------
9311	//
9312	//
9313
9314	/// \name Name Lookup
9315	///
9316	/// These routines provide name lookup that is used during semantic
9317	/// analysis to resolve the various kinds of names (identifiers,
9318	/// overloaded operator names, constructor names, etc.) into zero or
9319	/// more declarations within a particular scope. The major entry
9320	/// points are LookupName, which performs unqualified name lookup,
9321	/// and LookupQualifiedName, which performs qualified name lookup.
9322	///
9323	/// All name lookup is performed based on some specific criteria,
9324	/// which specify what names will be visible to name lookup and how
9325	/// far name lookup should work. These criteria are important both
9326	/// for capturing language semantics (certain lookups will ignore
9327	/// certain names, for example) and for performance, since name
9328	/// lookup is often a bottleneck in the compilation of C++. Name
9329	/// lookup criteria is specified via the LookupCriteria enumeration.
9330	///
9331	/// The results of name lookup can vary based on the kind of name
9332	/// lookup performed, the current language, and the translation
9333	/// unit. In C, for example, name lookup will either return nothing
9334	/// (no entity found) or a single declaration. In C++, name lookup
9335	/// can additionally refer to a set of overloaded functions or
9336	/// result in an ambiguity. All of the possible results of name
9337	/// lookup are captured by the LookupResult class, which provides
9338	/// the ability to distinguish among them.
9339	///
9340	/// Implementations are in SemaLookup.cpp
9341	///@{
9342
9343	public:
9344	/// Tracks whether we are in a context where typo correction is
9345	/// disabled.
9346	bool DisableTypoCorrection;
9347
9348	/// The number of typos corrected by CorrectTypo.
9349	unsigned TyposCorrected;
9350
9351	typedef llvm::SmallSet<SourceLocation, `2`> SrcLocSet;
9352	typedef llvm::DenseMap<IdentifierInfo *, SrcLocSet> IdentifierSourceLocations;
9353
9354	/// A cache containing identifiers for which typo correction failed and
9355	/// their locations, so that repeated attempts to correct an identifier in a
9356	/// given location are ignored if typo correction already failed for it.
9357	IdentifierSourceLocations TypoCorrectionFailures;
9358
9359	/// SpecialMemberOverloadResult - The overloading result for a special member
9360	/// function.
9361	///
9362	/// This is basically a wrapper around PointerIntPair. The lowest bits of the
9363	/// integer are used to determine whether overload resolution succeeded.
9364	class SpecialMemberOverloadResult {
9365	public:
9366	enum Kind { NoMemberOrDeleted, Ambiguous, Success };
9367
9368	private:
9369	llvm::PointerIntPair<CXXMethodDecl *, `2`> Pair;
9370
9371	public:
9372	SpecialMemberOverloadResult() {}
9373	SpecialMemberOverloadResult(CXXMethodDecl *MD)
9374	: Pair (MD, MD->isDeleted() ? NoMemberOrDeleted : Success) {}
9375
9376	CXXMethodDecl getMethod() const* { return Pair.getPointer(); }
9377	void setMethod(CXXMethodDecl *MD) { Pair.setPointer(MD); }
9378
9379	Kind getKind() const { return static_cast<Kind>(Pair.getInt()); }
9380	void setKind(Kind K) { Pair.setInt(K); }
9381	};
9382
9383	class SpecialMemberOverloadResultEntry : public llvm::FastFoldingSetNode,
9384	public SpecialMemberOverloadResult {
9385	public:
9386	SpecialMemberOverloadResultEntry(const llvm::FoldingSetNodeID &ID)
9387	: FastFoldingSetNode (ID) {}
9388	};
9389
9390	/// A cache of special member function overload resolution results
9391	/// for C++ records.
9392	llvm::FoldingSet<SpecialMemberOverloadResultEntry> SpecialMemberCache;
9393
9394	enum class AcceptableKind { Visible, Reachable };
9395
9396	// Members have to be NamespaceDecl or TranslationUnitDecl.
9397	// TODO: make this is a typesafe union.
9398	typedef llvm::SmallSetVector<DeclContext *, `16`> AssociatedNamespaceSet;
9399	typedef llvm::SmallSetVector<CXXRecordDecl *, `16`> AssociatedClassSet;
9400
9401	/// Describes the kind of name lookup to perform.
9402	enum LookupNameKind {
9403	/// Ordinary name lookup, which finds ordinary names (functions,
9404	/// variables, typedefs, etc.) in C and most kinds of names
9405	/// (functions, variables, members, types, etc.) in C++.
9406	LookupOrdinaryName = `0`,
9407	/// Tag name lookup, which finds the names of enums, classes,
9408	/// structs, and unions.
9409	LookupTagName,
9410	/// Label name lookup.
9411	LookupLabel,
9412	/// Member name lookup, which finds the names of
9413	/// class/struct/union members.
9414	LookupMemberName,
9415	/// Look up of an operator name (e.g., operator+) for use with
9416	/// operator overloading. This lookup is similar to ordinary name
9417	/// lookup, but will ignore any declarations that are class members.
9418	LookupOperatorName,
9419	/// Look up a name following ~ in a destructor name. This is an ordinary
9420	/// lookup, but prefers tags to typedefs.
9421	LookupDestructorName,
9422	/// Look up of a name that precedes the '::' scope resolution
9423	/// operator in C++. This lookup completely ignores operator, object,
9424	/// function, and enumerator names (C++ [basic.lookup.qual]p1).
9425	LookupNestedNameSpecifierName,
9426	/// Look up a namespace name within a C++ using directive or
9427	/// namespace alias definition, ignoring non-namespace names (C++
9428	/// [basic.lookup.udir]p1).
9429	LookupNamespaceName,
9430	/// Look up all declarations in a scope with the given name,
9431	/// including resolved using declarations. This is appropriate
9432	/// for checking redeclarations for a using declaration.
9433	LookupUsingDeclName,
9434	/// Look up an ordinary name that is going to be redeclared as a
9435	/// name with linkage. This lookup ignores any declarations that
9436	/// are outside of the current scope unless they have linkage. See
9437	/// C99 6.2.2p4-5 and C++ [basic.link]p6.
9438	LookupRedeclarationWithLinkage,
9439	/// Look up a friend of a local class. This lookup does not look
9440	/// outside the innermost non-class scope. See C++11 [class.friend]p11.
9441	LookupLocalFriendName,
9442	/// Look up the name of an Objective-C protocol.
9443	LookupObjCProtocolName,
9444	/// Look up implicit 'self' parameter of an objective-c method.
9445	LookupObjCImplicitSelfParam,
9446	/// Look up the name of an OpenMP user-defined reduction operation.
9447	LookupOMPReductionName,
9448	/// Look up the name of an OpenMP user-defined mapper.
9449	LookupOMPMapperName,
9450	/// Look up any declaration with any name.
9451	LookupAnyName
9452	};
9453
9454	/// The possible outcomes of name lookup for a literal operator.
9455	enum LiteralOperatorLookupResult {
9456	/// The lookup resulted in an error.
9457	LOLR_Error,
9458	/// The lookup found no match but no diagnostic was issued.
9459	LOLR_ErrorNoDiagnostic,
9460	/// The lookup found a single 'cooked' literal operator, which
9461	/// expects a normal literal to be built and passed to it.
9462	LOLR_Cooked,
9463	/// The lookup found a single 'raw' literal operator, which expects
9464	/// a string literal containing the spelling of the literal token.
9465	LOLR_Raw,
9466	/// The lookup found an overload set of literal operator templates,
9467	/// which expect the characters of the spelling of the literal token to be
9468	/// passed as a non-type template argument pack.
9469	LOLR_Template,
9470	/// The lookup found an overload set of literal operator templates,
9471	/// which expect the character type and characters of the spelling of the
9472	/// string literal token to be passed as template arguments.
9473	LOLR_StringTemplatePack,
9474	};
9475
9476	SpecialMemberOverloadResult
9477	LookupSpecialMember(CXXRecordDecl D, CXXSpecialMemberKind SM, bool* ConstArg,
9478	bool VolatileArg, bool RValueThis, bool ConstThis,
9479	bool VolatileThis);
9480
9481	RedeclarationKind forRedeclarationInCurContext() const;
9482
9483	/// Look up a name, looking for a single declaration. Return
9484	/// null if the results were absent, ambiguous, or overloaded.
9485	///
9486	/// It is preferable to use the elaborated form and explicitly handle
9487	/// ambiguity and overloaded.
9488	NamedDecl *LookupSingleName(
9489	Scope *S, DeclarationName Name, SourceLocation Loc,
9490	LookupNameKind NameKind,
9491	RedeclarationKind Redecl = RedeclarationKind::NotForRedeclaration);
9492
9493	/// Lookup a builtin function, when name lookup would otherwise
9494	/// fail.
9495	bool LookupBuiltin(LookupResult &R);
9496	void LookupNecessaryTypesForBuiltin(Scope S, unsigned* ID);
9497
9498	/// Perform unqualified name lookup starting from a given
9499	/// scope.
9500	///
9501	/// Unqualified name lookup (C++ [basic.lookup.unqual], C99 6.2.1) is
9502	/// used to find names within the current scope. For example, 'x' in
9503	/// @code
9504	/// int x;
9505	/// int f() {
9506	/// return x; // unqualified name look finds 'x' in the global scope
9507	/// }
9508	/// @endcode
9509	///
9510	/// Different lookup criteria can find different names. For example, a
9511	/// particular scope can have both a struct and a function of the same
9512	/// name, and each can be found by certain lookup criteria. For more
9513	/// information about lookup criteria, see the documentation for the
9514	/// class LookupCriteria.
9515	///
9516	/// @param S The scope from which unqualified name lookup will
9517	/// begin. If the lookup criteria permits, name lookup may also search
9518	/// in the parent scopes.
9519	///
9520	/// @param [in,out] R Specifies the lookup to perform (e.g., the name to
9521	/// look up and the lookup kind), and is updated with the results of lookup
9522	/// including zero or more declarations and possibly additional information
9523	/// used to diagnose ambiguities.
9524	///
9525	/// @returns \c true if lookup succeeded and false otherwise.
9526	bool LookupName(LookupResult &R, Scope S, bool* AllowBuiltinCreation = false,
9527	bool ForceNoCPlusPlus = false);
9528
9529	/// Perform qualified name lookup into a given context.
9530	///
9531	/// Qualified name lookup (C++ [basic.lookup.qual]) is used to find
9532	/// names when the context of those names is explicit specified, e.g.,
9533	/// "std::vector" or "x->member", or as part of unqualified name lookup.
9534	///
9535	/// Different lookup criteria can find different names. For example, a
9536	/// particular scope can have both a struct and a function of the same
9537	/// name, and each can be found by certain lookup criteria. For more
9538	/// information about lookup criteria, see the documentation for the
9539	/// class LookupCriteria.
9540	///
9541	/// \param R captures both the lookup criteria and any lookup results found.
9542	///
9543	/// \param LookupCtx The context in which qualified name lookup will
9544	/// search. If the lookup criteria permits, name lookup may also search
9545	/// in the parent contexts or (for C++ classes) base classes.
9546	///
9547	/// \param InUnqualifiedLookup true if this is qualified name lookup that
9548	/// occurs as part of unqualified name lookup.
9549	///
9550	/// \returns true if lookup succeeded, false if it failed.
9551	bool LookupQualifiedName(LookupResult &R, DeclContext *LookupCtx,
9552	bool InUnqualifiedLookup = false);
9553
9554	/// Performs qualified name lookup or special type of lookup for
9555	/// "__super::" scope specifier.
9556	///
9557	/// This routine is a convenience overload meant to be called from contexts
9558	/// that need to perform a qualified name lookup with an optional C++ scope
9559	/// specifier that might require special kind of lookup.
9560	///
9561	/// \param R captures both the lookup criteria and any lookup results found.
9562	///
9563	/// \param LookupCtx The context in which qualified name lookup will
9564	/// search.
9565	///
9566	/// \param SS An optional C++ scope-specifier.
9567	///
9568	/// \returns true if lookup succeeded, false if it failed.
9569	bool LookupQualifiedName(LookupResult &R, DeclContext *LookupCtx,
9570	CXXScopeSpec &SS);
9571
9572	/// Performs name lookup for a name that was parsed in the
9573	/// source code, and may contain a C++ scope specifier.
9574	///
9575	/// This routine is a convenience routine meant to be called from
9576	/// contexts that receive a name and an optional C++ scope specifier
9577	/// (e.g., "N::M::x"). It will then perform either qualified or
9578	/// unqualified name lookup (with LookupQualifiedName or LookupName,
9579	/// respectively) on the given name and return those results. It will
9580	/// perform a special type of lookup for "__super::" scope specifier.
9581	///
9582	/// @param S The scope from which unqualified name lookup will
9583	/// begin.
9584	///
9585	/// @param SS An optional C++ scope-specifier, e.g., "::N::M".
9586	///
9587	/// @param EnteringContext Indicates whether we are going to enter the
9588	/// context of the scope-specifier SS (if present).
9589	///
9590	/// @returns True if any decls were found (but possibly ambiguous)
9591	bool LookupParsedName(LookupResult &R, Scope S, CXXScopeSpec SS,
9592	QualType ObjectType, bool AllowBuiltinCreation = false,
9593	bool EnteringContext = false);
9594
9595	/// Perform qualified name lookup into all base classes of the given
9596	/// class.
9597	///
9598	/// \param R captures both the lookup criteria and any lookup results found.
9599	///
9600	/// \param Class The context in which qualified name lookup will
9601	/// search. Name lookup will search in all base classes merging the results.
9602	///
9603	/// @returns True if any decls were found (but possibly ambiguous)
9604	bool LookupInSuper(LookupResult &R, CXXRecordDecl *Class);
9605
9606	void LookupOverloadedOperatorName(OverloadedOperatorKind Op, Scope *S,
9607	UnresolvedSetImpl &Functions);
9608
9609	/// LookupOrCreateLabel - Do a name lookup of a label with the specified name.
9610	/// If GnuLabelLoc is a valid source location, then this is a definition
9611	/// of an __label__ label name, otherwise it is a normal label definition
9612	/// or use.
9613	LabelDecl LookupOrCreateLabel(IdentifierInfo II, SourceLocation IdentLoc,
9614	SourceLocation GnuLabelLoc = SourceLocation ());
9615
9616	/// Perform a name lookup for a label with the specified name; this does not
9617	/// create a new label if the lookup fails.
9618	LabelDecl LookupExistingLabel(IdentifierInfo II, SourceLocation IdentLoc);
9619
9620	/// Look up the constructors for the given class.
9621	DeclContextLookupResult LookupConstructors(CXXRecordDecl *Class);
9622
9623	/// Look up the default constructor for the given class.
9624	CXXConstructorDecl LookupDefaultConstructor(CXXRecordDecl Class);
9625
9626	/// Look up the copying constructor for the given class.
9627	CXXConstructorDecl LookupCopyingConstructor(CXXRecordDecl Class,
9628	unsigned Quals);
9629
9630	/// Look up the copying assignment operator for the given class.
9631	CXXMethodDecl LookupCopyingAssignment(CXXRecordDecl Class, unsigned Quals,
9632	bool RValueThis, unsigned ThisQuals);
9633
9634	/// Look up the moving constructor for the given class.
9635	CXXConstructorDecl LookupMovingConstructor(CXXRecordDecl Class,
9636	unsigned Quals);
9637
9638	/// Look up the moving assignment operator for the given class.
9639	CXXMethodDecl LookupMovingAssignment(CXXRecordDecl Class, unsigned Quals,
9640	bool RValueThis, unsigned ThisQuals);
9641
9642	/// Look for the destructor of the given class.
9643	///
9644	/// During semantic analysis, this routine should be used in lieu of
9645	/// CXXRecordDecl::getDestructor().
9646	///
9647	/// \returns The destructor for this class.
9648	CXXDestructorDecl LookupDestructor(CXXRecordDecl Class);
9649
9650	/// Force the declaration of any implicitly-declared members of this
9651	/// class.
9652	void ForceDeclarationOfImplicitMembers(CXXRecordDecl *Class);
9653
9654	/// Make a merged definition of an existing hidden definition \p ND
9655	/// visible at the specified location.
9656	void makeMergedDefinitionVisible(NamedDecl *ND);
9657
9658	/// Check ODR hashes for C/ObjC when merging types from modules.
9659	/// Differently from C++, actually parse the body and reject in case
9660	/// of a mismatch.
9661	template <typename T,
9662	typename = std::enable_if_t<std::is_base_of<NamedDecl, T>::value>>
9663	bool ActOnDuplicateODRHashDefinition(T Duplicate, T Previous) {
9664	if (Duplicate->getODRHash() != Previous->getODRHash())
9665	return false;
9666
9667	// Make the previous decl visible.
9668	makeMergedDefinitionVisible(ND: Previous);
9669	return true;
9670	}
9671
9672	/// Get the set of additional modules that should be checked during
9673	/// name lookup. A module and its imports become visible when instanting a
9674	/// template defined within it.
9675	llvm::DenseSet<Module *> &getLookupModules();
9676
9677	bool hasVisibleMergedDefinition(const NamedDecl *Def);
9678	bool hasMergedDefinitionInCurrentModule(const NamedDecl *Def);
9679
9680	/// Determine if the template parameter \p D has a visible default argument.
9681	bool
9682	hasVisibleDefaultArgument(const NamedDecl *D,
9683	llvm::SmallVectorImpl<Module > Modules = nullptr);
9684	/// Determine if the template parameter \p D has a reachable default argument.
9685	bool hasReachableDefaultArgument(
9686	const NamedDecl D, llvm::SmallVectorImpl<Module > Modules = nullptr*);
9687	/// Determine if the template parameter \p D has a reachable default argument.
9688	bool hasAcceptableDefaultArgument(const NamedDecl *D,
9689	llvm::SmallVectorImpl<Module > Modules,
9690	Sema::AcceptableKind Kind);
9691
9692	/// Determine if there is a visible declaration of \p D that is an explicit
9693	/// specialization declaration for a specialization of a template. (For a
9694	/// member specialization, use hasVisibleMemberSpecialization.)
9695	bool hasVisibleExplicitSpecialization(
9696	const NamedDecl D, llvm::SmallVectorImpl<Module > Modules = nullptr*);
9697	/// Determine if there is a reachable declaration of \p D that is an explicit
9698	/// specialization declaration for a specialization of a template. (For a
9699	/// member specialization, use hasReachableMemberSpecialization.)
9700	bool hasReachableExplicitSpecialization(
9701	const NamedDecl D, llvm::SmallVectorImpl<Module > Modules = nullptr*);
9702
9703	/// Determine if there is a visible declaration of \p D that is a member
9704	/// specialization declaration (as opposed to an instantiated declaration).
9705	bool hasVisibleMemberSpecialization(
9706	const NamedDecl D, llvm::SmallVectorImpl<Module > Modules = nullptr*);
9707	/// Determine if there is a reachable declaration of \p D that is a member
9708	/// specialization declaration (as opposed to an instantiated declaration).
9709	bool hasReachableMemberSpecialization(
9710	const NamedDecl D, llvm::SmallVectorImpl<Module > Modules = nullptr*);
9711
9712	bool isModuleVisible(const Module M, bool* ModulePrivate = false);
9713
9714	/// Determine whether any declaration of an entity is visible.
9715	bool
9716	hasVisibleDeclaration(const NamedDecl *D,
9717	llvm::SmallVectorImpl<Module > Modules = nullptr) {
9718	return isVisible(D) \|\| hasVisibleDeclarationSlow(D, Modules);
9719	}
9720
9721	bool hasVisibleDeclarationSlow(const NamedDecl *D,
9722	llvm::SmallVectorImpl<Module > Modules);
9723	/// Determine whether any declaration of an entity is reachable.
9724	bool
9725	hasReachableDeclaration(const NamedDecl *D,
9726	llvm::SmallVectorImpl<Module > Modules = nullptr) {
9727	return isReachable(D) \|\| hasReachableDeclarationSlow(D, Modules);
9728	}
9729	bool hasReachableDeclarationSlow(
9730	const NamedDecl D, llvm::SmallVectorImpl<Module > Modules = nullptr*);
9731
9732	void diagnoseTypo(const TypoCorrection &Correction,
9733	const PartialDiagnostic &TypoDiag,
9734	bool ErrorRecovery = true);
9735
9736	/// Diagnose a successfully-corrected typo. Separated from the correction
9737	/// itself to allow external validation of the result, etc.
9738	///
9739	/// \param Correction The result of performing typo correction.
9740	/// \param TypoDiag The diagnostic to produce. This will have the corrected
9741	/// string added to it (and usually also a fixit).
9742	/// \param PrevNote A note to use when indicating the location of the entity
9743	/// to which we are correcting. Will have the correction string added
9744	/// to it.
9745	/// \param ErrorRecovery If \c true (the default), the caller is going to
9746	/// recover from the typo as if the corrected string had been typed.
9747	/// In this case, \c PDiag must be an error, and we will attach a fixit
9748	/// to it.
9749	void diagnoseTypo(const TypoCorrection &Correction,
9750	const PartialDiagnostic &TypoDiag,
9751	const PartialDiagnostic &PrevNote,
9752	bool ErrorRecovery = true);
9753
9754	/// Find the associated classes and namespaces for
9755	/// argument-dependent lookup for a call with the given set of
9756	/// arguments.
9757	///
9758	/// This routine computes the sets of associated classes and associated
9759	/// namespaces searched by argument-dependent lookup
9760	/// (C++ [basic.lookup.argdep]) for a given set of arguments.
9761	void FindAssociatedClassesAndNamespaces(
9762	SourceLocation InstantiationLoc, ArrayRef<Expr *> Args,
9763	AssociatedNamespaceSet &AssociatedNamespaces,
9764	AssociatedClassSet &AssociatedClasses);
9765
9766	/// Produce a diagnostic describing the ambiguity that resulted
9767	/// from name lookup.
9768	///
9769	/// \param Result The result of the ambiguous lookup to be diagnosed.
9770	void DiagnoseAmbiguousLookup(LookupResult &Result);
9771
9772	/// LookupLiteralOperator - Determine which literal operator should be used
9773	/// for a user-defined literal, per C++11 [lex.ext].
9774	///
9775	/// Normal overload resolution is not used to select which literal operator to
9776	/// call for a user-defined literal. Look up the provided literal operator
9777	/// name, and filter the results to the appropriate set for the given argument
9778	/// types.
9779	LiteralOperatorLookupResult
9780	LookupLiteralOperator(Scope *S, LookupResult &R, ArrayRef<QualType> ArgTys,
9781	bool AllowRaw, bool AllowTemplate,
9782	bool AllowStringTemplate, bool DiagnoseMissing,
9783	StringLiteral StringLit = nullptr*);
9784
9785	void ArgumentDependentLookup(DeclarationName Name, SourceLocation Loc,
9786	ArrayRef<Expr *> Args, ADLResult &Functions);
9787
9788	void LookupVisibleDecls(Scope *S, LookupNameKind Kind,
9789	VisibleDeclConsumer &Consumer,
9790	bool IncludeGlobalScope = true,
9791	bool LoadExternal = true);
9792	void LookupVisibleDecls(DeclContext *Ctx, LookupNameKind Kind,
9793	VisibleDeclConsumer &Consumer,
9794	bool IncludeGlobalScope = true,
9795	bool IncludeDependentBases = false,
9796	bool LoadExternal = true);
9797
9798	/// Try to "correct" a typo in the source code by finding
9799	/// visible declarations whose names are similar to the name that was
9800	/// present in the source code.
9801	///
9802	/// \param TypoName the \c DeclarationNameInfo structure that contains
9803	/// the name that was present in the source code along with its location.
9804	///
9805	/// \param LookupKind the name-lookup criteria used to search for the name.
9806	///
9807	/// \param S the scope in which name lookup occurs.
9808	///
9809	/// \param SS the nested-name-specifier that precedes the name we're
9810	/// looking for, if present.
9811	///
9812	/// \param CCC A CorrectionCandidateCallback object that provides further
9813	/// validation of typo correction candidates. It also provides flags for
9814	/// determining the set of keywords permitted.
9815	///
9816	/// \param MemberContext if non-NULL, the context in which to look for
9817	/// a member access expression.
9818	///
9819	/// \param EnteringContext whether we're entering the context described by
9820	/// the nested-name-specifier SS.
9821	///
9822	/// \param OPT when non-NULL, the search for visible declarations will
9823	/// also walk the protocols in the qualified interfaces of \p OPT.
9824	///
9825	/// \returns a \c TypoCorrection containing the corrected name if the typo
9826	/// along with information such as the \c NamedDecl where the corrected name
9827	/// was declared, and any additional \c NestedNameSpecifier needed to access
9828	/// it (C++ only). The \c TypoCorrection is empty if there is no correction.
9829	TypoCorrection CorrectTypo(const DeclarationNameInfo &Typo,
9830	Sema::LookupNameKind LookupKind, Scope *S,
9831	CXXScopeSpec *SS, CorrectionCandidateCallback &CCC,
9832	CorrectTypoKind Mode,
9833	DeclContext MemberContext = nullptr*,
9834	bool EnteringContext = false,
9835	const ObjCObjectPointerType OPT = nullptr*,
9836	bool RecordFailure = true);
9837
9838	/// Kinds of missing import. Note, the values of these enumerators correspond
9839	/// to %select values in diagnostics.
9840	enum class MissingImportKind {
9841	Declaration,
9842	Definition,
9843	DefaultArgument,
9844	ExplicitSpecialization,
9845	PartialSpecialization
9846	};
9847
9848	/// Diagnose that the specified declaration needs to be visible but
9849	/// isn't, and suggest a module import that would resolve the problem.
9850	void diagnoseMissingImport(SourceLocation Loc, const NamedDecl *Decl,
9851	MissingImportKind MIK, bool Recover = true);
9852	void diagnoseMissingImport(SourceLocation Loc, const NamedDecl *Decl,
9853	SourceLocation DeclLoc, ArrayRef<Module *> Modules,
9854	MissingImportKind MIK, bool Recover);
9855
9856	/// Called on #pragma clang __debug dump II
9857	void ActOnPragmaDump(Scope S, SourceLocation Loc, IdentifierInfo II);
9858
9859	/// Called on #pragma clang __debug dump E
9860	void ActOnPragmaDump(Expr *E);
9861
9862	private:
9863	// The set of known/encountered (unique, canonicalized) NamespaceDecls.
9864	//
9865	// The boolean value will be true to indicate that the namespace was loaded
9866	// from an AST/PCH file, or false otherwise.
9867	llvm::MapVector<NamespaceDecl , bool*> KnownNamespaces;
9868
9869	/// Whether we have already loaded known namespaces from an extenal
9870	/// source.
9871	bool LoadedExternalKnownNamespaces;
9872
9873	bool CppLookupName(LookupResult &R, Scope *S);
9874
9875	/// Determine if we could use all the declarations in the module.
9876	bool isUsableModule(const Module *M);
9877
9878	/// Helper for CorrectTypo used to create and populate a new
9879	/// TypoCorrectionConsumer. Returns nullptr if typo correction should be
9880	/// skipped entirely.
9881	std::unique_ptr<TypoCorrectionConsumer> makeTypoCorrectionConsumer(
9882	const DeclarationNameInfo &Typo, Sema::LookupNameKind LookupKind,
9883	Scope S, CXXScopeSpec SS, CorrectionCandidateCallback &CCC,
9884	DeclContext MemberContext, bool* EnteringContext,
9885	const ObjCObjectPointerType OPT, bool* ErrorRecovery);
9886
9887	/// Cache for module units which is usable for current module.
9888	llvm::DenseSet<const Module *> UsableModuleUnitsCache;
9889
9890	/// Record the typo correction failure and return an empty correction.
9891	TypoCorrection FailedCorrection(IdentifierInfo *Typo, SourceLocation TypoLoc,
9892	bool RecordFailure = true) {
9893	if (RecordFailure)
9894	TypoCorrectionFailures [Typo].insert(V: TypoLoc);
9895	return TypoCorrection ();
9896	}
9897
9898	bool isAcceptableSlow(const NamedDecl *D, AcceptableKind Kind);
9899
9900	/// Determine whether two declarations should be linked together, given that
9901	/// the old declaration might not be visible and the new declaration might
9902	/// not have external linkage.
9903	bool shouldLinkPossiblyHiddenDecl(const NamedDecl *Old,
9904	const NamedDecl *New) {
9905	if (isVisible(D: Old))
9906	return true;
9907	// See comment in below overload for why it's safe to compute the linkage
9908	// of the new declaration here.
9909	if (New->isExternallyDeclarable()) {
9910	assert(Old->isExternallyDeclarable() &&
9911	"should not have found a non-externally-declarable previous decl");
9912	return true;
9913	}
9914	return false;
9915	}
9916	bool shouldLinkPossiblyHiddenDecl(LookupResult &Old, const NamedDecl *New);
9917
9918	///@}
9919
9920	//
9921	//
9922	// -------------------------------------------------------------------------
9923	//
9924	//
9925
9926	/// \name Modules
9927	/// Implementations are in SemaModule.cpp
9928	///@{
9929
9930	public:
9931	/// Get the module unit whose scope we are currently within.
9932	Module getCurrentModule() const* {
9933	return ModuleScopes.empty() ? nullptr : ModuleScopes.back().Module;
9934	}
9935
9936	/// Is the module scope we are an implementation unit?
9937	bool currentModuleIsImplementation() const {
9938	if (ModuleScopes.empty())
9939	return false;
9940	const Module *M = ModuleScopes.back().Module;
9941	return M->isModuleImplementation() \|\| M->isModulePartitionImplementation();
9942	}
9943
9944	// When loading a non-modular PCH files, this is used to restore module
9945	// visibility.
9946	void makeModuleVisible(Module *Mod, SourceLocation ImportLoc) {
9947	VisibleModules.setVisible(M: Mod, Loc: ImportLoc);
9948	}
9949
9950	enum class ModuleDeclKind {
9951	Interface, ///< 'export module X;'
9952	Implementation, ///< 'module X;'
9953	PartitionInterface, ///< 'export module X:Y;'
9954	PartitionImplementation, ///< 'module X:Y;'
9955	};
9956
9957	/// An enumeration to represent the transition of states in parsing module
9958	/// fragments and imports. If we are not parsing a C++20 TU, or we find
9959	/// an error in state transition, the state is set to NotACXX20Module.
9960	enum class ModuleImportState {
9961	FirstDecl, ///< Parsing the first decl in a TU.
9962	GlobalFragment, ///< after 'module;' but before 'module X;'
9963	ImportAllowed, ///< after 'module X;' but before any non-import decl.
9964	ImportFinished, ///< after any non-import decl.
9965	PrivateFragmentImportAllowed, ///< after 'module :private;' but before any
9966	///< non-import decl.
9967	PrivateFragmentImportFinished, ///< after 'module :private;' but a
9968	///< non-import decl has already been seen.
9969	NotACXX20Module ///< Not a C++20 TU, or an invalid state was found.
9970	};
9971
9972	/// The parser has processed a module-declaration that begins the definition
9973	/// of a module interface or implementation.
9974	DeclGroupPtrTy ActOnModuleDecl(SourceLocation StartLoc,
9975	SourceLocation ModuleLoc, ModuleDeclKind MDK,
9976	ModuleIdPath Path, ModuleIdPath Partition,
9977	ModuleImportState &ImportState,
9978	bool SeenNoTrivialPPDirective);
9979
9980	/// The parser has processed a global-module-fragment declaration that begins
9981	/// the definition of the global module fragment of the current module unit.
9982	/// \param ModuleLoc The location of the 'module' keyword.
9983	DeclGroupPtrTy ActOnGlobalModuleFragmentDecl(SourceLocation ModuleLoc);
9984
9985	/// The parser has processed a private-module-fragment declaration that begins
9986	/// the definition of the private module fragment of the current module unit.
9987	/// \param ModuleLoc The location of the 'module' keyword.
9988	/// \param PrivateLoc The location of the 'private' keyword.
9989	DeclGroupPtrTy ActOnPrivateModuleFragmentDecl(SourceLocation ModuleLoc,
9990	SourceLocation PrivateLoc);
9991
9992	/// The parser has processed a module import declaration.
9993	///
9994	/// \param StartLoc The location of the first token in the declaration. This
9995	/// could be the location of an '@', 'export', or 'import'.
9996	/// \param ExportLoc The location of the 'export' keyword, if any.
9997	/// \param ImportLoc The location of the 'import' keyword.
9998	/// \param Path The module toplevel name as an access path.
9999	/// \param IsPartition If the name is for a partition.
10000	DeclResult ActOnModuleImport(SourceLocation StartLoc,
10001	SourceLocation ExportLoc,
10002	SourceLocation ImportLoc, ModuleIdPath Path,
10003	bool IsPartition = false);
10004	DeclResult ActOnModuleImport(SourceLocation StartLoc,
10005	SourceLocation ExportLoc,
10006	SourceLocation ImportLoc, Module *M,
10007	ModuleIdPath Path = {});
10008
10009	/// The parser has processed a module import translated from a
10010	/// #include or similar preprocessing directive.
10011	void ActOnAnnotModuleInclude(SourceLocation DirectiveLoc, Module *Mod);
10012	void BuildModuleInclude(SourceLocation DirectiveLoc, Module *Mod);
10013
10014	/// The parsed has entered a submodule.
10015	void ActOnAnnotModuleBegin(SourceLocation DirectiveLoc, Module *Mod);
10016	/// The parser has left a submodule.
10017	void ActOnAnnotModuleEnd(SourceLocation DirectiveLoc, Module *Mod);
10018
10019	/// Create an implicit import of the given module at the given
10020	/// source location, for error recovery, if possible.
10021	///
10022	/// This routine is typically used when an entity found by name lookup
10023	/// is actually hidden within a module that we know about but the user
10024	/// has forgotten to import.
10025	void createImplicitModuleImportForErrorRecovery(SourceLocation Loc,
10026	Module *Mod);
10027
10028	/// We have parsed the start of an export declaration, including the '{'
10029	/// (if present).
10030	Decl ActOnStartExportDecl(Scope S, SourceLocation ExportLoc,
10031	SourceLocation LBraceLoc);
10032
10033	/// Complete the definition of an export declaration.
10034	Decl ActOnFinishExportDecl(Scope S, Decl *ExportDecl,
10035	SourceLocation RBraceLoc);
10036
10037	private:
10038	/// The parser has begun a translation unit to be compiled as a C++20
10039	/// Header Unit, helper for ActOnStartOfTranslationUnit() only.
10040	void HandleStartOfHeaderUnit();
10041
10042	struct ModuleScope {
10043	SourceLocation BeginLoc;
10044	clang::Module Module = nullptr*;
10045	VisibleModuleSet OuterVisibleModules;
10046	};
10047	/// The modules we're currently parsing.
10048	llvm::SmallVector<ModuleScope, `16`> ModuleScopes;
10049
10050	/// For an interface unit, this is the implicitly imported interface unit.
10051	clang::Module ThePrimaryInterface = nullptr*;
10052
10053	/// The explicit global module fragment of the current translation unit.
10054	/// The explicit Global Module Fragment, as specified in C++
10055	/// [module.global.frag].
10056	clang::Module TheGlobalModuleFragment = nullptr*;
10057
10058	/// The implicit global module fragments of the current translation unit.
10059	///
10060	/// The contents in the implicit global module fragment can't be discarded.
10061	clang::Module TheImplicitGlobalModuleFragment = nullptr*;
10062
10063	/// Namespace definitions that we will export when they finish.
10064	llvm::SmallPtrSet<const NamespaceDecl *, `8`> DeferredExportedNamespaces;
10065
10066	/// In a C++ standard module, inline declarations require a definition to be
10067	/// present at the end of a definition domain. This set holds the decls to
10068	/// be checked at the end of the TU.
10069	llvm::SmallPtrSet<const FunctionDecl *, `8`> PendingInlineFuncDecls;
10070
10071	/// Helper function to judge if we are in module purview.
10072	/// Return false if we are not in a module.
10073	bool isCurrentModulePurview() const;
10074
10075	/// Enter the scope of the explicit global module fragment.
10076	Module *PushGlobalModuleFragment(SourceLocation BeginLoc);
10077	/// Leave the scope of the explicit global module fragment.
10078	void PopGlobalModuleFragment();
10079
10080	/// Enter the scope of an implicit global module fragment.
10081	Module *PushImplicitGlobalModuleFragment(SourceLocation BeginLoc);
10082	/// Leave the scope of an implicit global module fragment.
10083	void PopImplicitGlobalModuleFragment();
10084
10085	VisibleModuleSet VisibleModules;
10086
10087	/// Whether we had imported any named modules.
10088	bool HadImportedNamedModules = false;
10089	/// The set of instantiations we need to check if they references TU-local
10090	/// entity from TUs. This only makes sense if we imported any named modules.
10091	llvm::SmallVector<std::pair<FunctionDecl *, SourceLocation>>
10092	PendingCheckReferenceForTULocal;
10093	/// Implement [basic.link]p18, which requires that we can't use TU-local
10094	/// entities from other TUs (ignoring header units).
10095	void checkReferenceToTULocalFromOtherTU(FunctionDecl *FD,
10096	SourceLocation PointOfInstantiation);
10097	/// Implement [basic.link]p17, which diagnose for non TU local exposure in
10098	/// module interface or module partition.
10099	void checkExposure(const TranslationUnitDecl *TU);
10100
10101	///@}
10102
10103	//
10104	//
10105	// -------------------------------------------------------------------------
10106	//
10107	//
10108
10109	/// \name C++ Overloading
10110	/// Implementations are in SemaOverload.cpp
10111	///@{
10112
10113	public:
10114	/// Whether deferrable diagnostics should be deferred.
10115	bool DeferDiags = false;
10116
10117	/// RAII class to control scope of DeferDiags.
10118	class DeferDiagsRAII {
10119	Sema &S;
10120	bool SavedDeferDiags = false;
10121
10122	public:
10123	DeferDiagsRAII(Sema &S, bool DeferDiags)
10124	: S(S), SavedDeferDiags(S.DeferDiags) {
10125	S.DeferDiags = SavedDeferDiags \|\| DeferDiags;
10126	}
10127	~DeferDiagsRAII() { S.DeferDiags = SavedDeferDiags; }
10128	DeferDiagsRAII(const DeferDiagsRAII &) = delete;
10129	DeferDiagsRAII &operator=(const DeferDiagsRAII &) = delete;
10130	};
10131
10132	/// Flag indicating if Sema is building a recovery call expression.
10133	///
10134	/// This flag is used to avoid building recovery call expressions
10135	/// if Sema is already doing so, which would cause infinite recursions.
10136	bool IsBuildingRecoveryCallExpr;
10137
10138	/// Determine whether the given New declaration is an overload of the
10139	/// declarations in Old. This routine returns OverloadKind::Match or
10140	/// OverloadKind::NonFunction if New and Old cannot be overloaded, e.g., if
10141	/// New has the same signature as some function in Old (C++ 1.3.10) or if the
10142	/// Old declarations aren't functions (or function templates) at all. When it
10143	/// does return OverloadKind::Match or OverloadKind::NonFunction, MatchedDecl
10144	/// will point to the decl that New cannot be overloaded with. This decl may
10145	/// be a UsingShadowDecl on top of the underlying declaration.
10146	///
10147	/// Example: Given the following input:
10148	///
10149	/// void f(int, float); // #1
10150	/// void f(int, int); // #2
10151	/// int f(int, int); // #3
10152	///
10153	/// When we process #1, there is no previous declaration of "f", so IsOverload
10154	/// will not be used.
10155	///
10156	/// When we process #2, Old contains only the FunctionDecl for #1. By
10157	/// comparing the parameter types, we see that #1 and #2 are overloaded (since
10158	/// they have different signatures), so this routine returns
10159	/// OverloadKind::Overload; MatchedDecl is unchanged.
10160	///
10161	/// When we process #3, Old is an overload set containing #1 and #2. We
10162	/// compare the signatures of #3 to #1 (they're overloaded, so we do nothing)
10163	/// and then #3 to #2. Since the signatures of #3 and #2 are identical (return
10164	/// types of functions are not part of the signature), IsOverload returns
10165	/// OverloadKind::Match and MatchedDecl will be set to point to the
10166	/// FunctionDecl for #2.
10167	///
10168	/// 'NewIsUsingShadowDecl' indicates that 'New' is being introduced into a
10169	/// class by a using declaration. The rules for whether to hide shadow
10170	/// declarations ignore some properties which otherwise figure into a function
10171	/// template's signature.
10172	OverloadKind CheckOverload(Scope S, FunctionDecl New,
10173	const LookupResult &OldDecls, NamedDecl *&OldDecl,
10174	bool UseMemberUsingDeclRules);
10175	bool IsOverload(FunctionDecl New, FunctionDecl Old,
10176	bool UseMemberUsingDeclRules, bool ConsiderCudaAttrs = true);
10177
10178	// Checks whether MD constitutes an override the base class method BaseMD.
10179	// When checking for overrides, the object object members are ignored.
10180	bool IsOverride(FunctionDecl MD, FunctionDecl BaseMD,
10181	bool UseMemberUsingDeclRules, bool ConsiderCudaAttrs = true);
10182
10183	enum class AllowedExplicit {
10184	/// Allow no explicit functions to be used.
10185	None,
10186	/// Allow explicit conversion functions but not explicit constructors.
10187	Conversions,
10188	/// Allow both explicit conversion functions and explicit constructors.
10189	All
10190	};
10191
10192	ImplicitConversionSequence TryImplicitConversion(
10193	Expr From, QualType ToType, bool* SuppressUserConversions,
10194	AllowedExplicit AllowExplicit, bool InOverloadResolution, bool CStyle,
10195	bool AllowObjCWritebackConversion);
10196
10197	/// PerformImplicitConversion - Perform an implicit conversion of the
10198	/// expression From to the type ToType. Returns the
10199	/// converted expression. Flavor is the kind of conversion we're
10200	/// performing, used in the error message. If @p AllowExplicit,
10201	/// explicit user-defined conversions are permitted.
10202	ExprResult PerformImplicitConversion(Expr *From, QualType ToType,
10203	AssignmentAction Action,
10204	bool AllowExplicit = false);
10205
10206	/// IsIntegralPromotion - Determines whether the conversion from the
10207	/// expression From (whose potentially-adjusted type is FromType) to
10208	/// ToType is an integral promotion (C++ 4.5). If so, returns true and
10209	/// sets PromotedType to the promoted type.
10210	bool IsIntegralPromotion(Expr *From, QualType FromType, QualType ToType);
10211
10212	/// IsFloatingPointPromotion - Determines whether the conversion from
10213	/// FromType to ToType is a floating point promotion (C++ 4.6). If so,
10214	/// returns true and sets PromotedType to the promoted type.
10215	bool IsFloatingPointPromotion(QualType FromType, QualType ToType);
10216
10217	/// Determine if a conversion is a complex promotion.
10218	///
10219	/// A complex promotion is defined as a complex -> complex conversion
10220	/// where the conversion between the underlying real types is a
10221	/// floating-point or integral promotion.
10222	bool IsComplexPromotion(QualType FromType, QualType ToType);
10223
10224	/// IsOverflowBehaviorTypePromotion - Determines whether the conversion from
10225	/// FromType to ToType involves an OverflowBehaviorType FromType being
10226	/// promoted to an OverflowBehaviorType ToType which has a larger bitwidth.
10227	/// If so, returns true and sets FromType to ToType.
10228	bool IsOverflowBehaviorTypePromotion(QualType FromType, QualType ToType);
10229
10230	/// IsOverflowBehaviorTypeConversion - Determines whether the conversion from
10231	/// FromType to ToType necessarily involves both an OverflowBehaviorType and
10232	/// a non-OverflowBehaviorType. If so, returns true and sets FromType to
10233	/// ToType.
10234	bool IsOverflowBehaviorTypeConversion(QualType FromType, QualType ToType);
10235
10236	/// IsPointerConversion - Determines whether the conversion of the
10237	/// expression From, which has the (possibly adjusted) type FromType,
10238	/// can be converted to the type ToType via a pointer conversion (C++
10239	/// 4.10). If so, returns true and places the converted type (that
10240	/// might differ from ToType in its cv-qualifiers at some level) into
10241	/// ConvertedType.
10242	///
10243	/// This routine also supports conversions to and from block pointers
10244	/// and conversions with Objective-C's 'id', 'id<protocols...>', and
10245	/// pointers to interfaces. FIXME: Once we've determined the
10246	/// appropriate overloading rules for Objective-C, we may want to
10247	/// split the Objective-C checks into a different routine; however,
10248	/// GCC seems to consider all of these conversions to be pointer
10249	/// conversions, so for now they live here. IncompatibleObjC will be
10250	/// set if the conversion is an allowed Objective-C conversion that
10251	/// should result in a warning.
10252	bool IsPointerConversion(Expr *From, QualType FromType, QualType ToType,
10253	bool InOverloadResolution, QualType &ConvertedType,
10254	bool &IncompatibleObjC);
10255
10256	/// isObjCPointerConversion - Determines whether this is an
10257	/// Objective-C pointer conversion. Subroutine of IsPointerConversion,
10258	/// with the same arguments and return values.
10259	bool isObjCPointerConversion(QualType FromType, QualType ToType,
10260	QualType &ConvertedType, bool &IncompatibleObjC);
10261	bool IsBlockPointerConversion(QualType FromType, QualType ToType,
10262	QualType &ConvertedType);
10263
10264	/// FunctionParamTypesAreEqual - This routine checks two function proto types
10265	/// for equality of their parameter types. Caller has already checked that
10266	/// they have same number of parameters. If the parameters are different,
10267	/// ArgPos will have the parameter index of the first different parameter.
10268	/// If `Reversed` is true, the parameters of `NewType` will be compared in
10269	/// reverse order. That's useful if one of the functions is being used as a
10270	/// C++20 synthesized operator overload with a reversed parameter order.
10271	bool FunctionParamTypesAreEqual(ArrayRef<QualType> Old,
10272	ArrayRef<QualType> New,
10273	unsigned ArgPos = nullptr*,
10274	bool Reversed = false);
10275
10276	bool FunctionParamTypesAreEqual(const FunctionProtoType *OldType,
10277	const FunctionProtoType *NewType,
10278	unsigned ArgPos = nullptr*,
10279	bool Reversed = false);
10280
10281	bool FunctionNonObjectParamTypesAreEqual(const FunctionDecl *OldFunction,
10282	const FunctionDecl *NewFunction,
10283	unsigned ArgPos = nullptr*,
10284	bool Reversed = false);
10285
10286	/// HandleFunctionTypeMismatch - Gives diagnostic information for differeing
10287	/// function types. Catches different number of parameter, mismatch in
10288	/// parameter types, and different return types.
10289	void HandleFunctionTypeMismatch(PartialDiagnostic &PDiag, QualType FromType,
10290	QualType ToType);
10291
10292	/// CheckPointerConversion - Check the pointer conversion from the
10293	/// expression From to the type ToType. This routine checks for
10294	/// ambiguous or inaccessible derived-to-base pointer
10295	/// conversions for which IsPointerConversion has already returned
10296	/// true. It returns true and produces a diagnostic if there was an
10297	/// error, or returns false otherwise.
10298	bool CheckPointerConversion(Expr *From, QualType ToType, CastKind &Kind,
10299	CXXCastPath &BasePath, bool IgnoreBaseAccess,
10300	bool Diagnose = true);
10301
10302	/// IsMemberPointerConversion - Determines whether the conversion of the
10303	/// expression From, which has the (possibly adjusted) type FromType, can be
10304	/// converted to the type ToType via a member pointer conversion (C++ 4.11).
10305	/// If so, returns true and places the converted type (that might differ from
10306	/// ToType in its cv-qualifiers at some level) into ConvertedType.
10307	bool IsMemberPointerConversion(Expr *From, QualType FromType, QualType ToType,
10308	bool InOverloadResolution,
10309	QualType &ConvertedType);
10310
10311	enum class MemberPointerConversionResult {
10312	Success,
10313	DifferentPointee,
10314	NotDerived,
10315	Ambiguous,
10316	Virtual,
10317	Inaccessible
10318	};
10319	enum class MemberPointerConversionDirection : bool { Downcast, Upcast };
10320	/// CheckMemberPointerConversion - Check the member pointer conversion from
10321	/// the expression From to the type ToType. This routine checks for ambiguous
10322	/// or virtual or inaccessible base-to-derived member pointer conversions for
10323	/// which IsMemberPointerConversion has already returned true. It produces a
10324	// diagnostic if there was an error.
10325	MemberPointerConversionResult CheckMemberPointerConversion(
10326	QualType FromType, const MemberPointerType *ToPtrType, CastKind &Kind,
10327	CXXCastPath &BasePath, SourceLocation CheckLoc, SourceRange OpRange,
10328	bool IgnoreBaseAccess, MemberPointerConversionDirection Direction);
10329
10330	/// IsQualificationConversion - Determines whether the conversion from
10331	/// an rvalue of type FromType to ToType is a qualification conversion
10332	/// (C++ 4.4).
10333	///
10334	/// \param ObjCLifetimeConversion Output parameter that will be set to
10335	/// indicate when the qualification conversion involves a change in the
10336	/// Objective-C object lifetime.
10337	bool IsQualificationConversion(QualType FromType, QualType ToType,
10338	bool CStyle, bool &ObjCLifetimeConversion);
10339
10340	/// Determine whether the conversion from FromType to ToType is a valid
10341	/// conversion of ExtInfo/ExtProtoInfo on the nested function type.
10342	/// More precisely, this method checks whether FromType can be transformed
10343	/// into an exact match for ToType, by transforming its extended function
10344	/// type information in legal manner (e.g. by strictly stripping "noreturn"
10345	/// or "noexcept", or by stripping "noescape" for arguments).
10346	bool IsFunctionConversion(QualType FromType, QualType ToType) const;
10347
10348	/// Same as `IsFunctionConversion`, but if this would return true, it sets
10349	/// `ResultTy` to `ToType`.
10350	bool TryFunctionConversion(QualType FromType, QualType ToType,
10351	QualType &ResultTy) const;
10352
10353	bool DiagnoseMultipleUserDefinedConversion(Expr *From, QualType ToType);
10354	void DiagnoseUseOfDeletedFunction(SourceLocation Loc, SourceRange Range,
10355	DeclarationName Name,
10356	OverloadCandidateSet &CandidateSet,
10357	FunctionDecl *Fn, MultiExprArg Args,
10358	bool IsMember = false);
10359
10360	ExprResult InitializeExplicitObjectArgument(Sema &S, Expr *Obj,
10361	FunctionDecl *Fun);
10362	ExprResult PerformImplicitObjectArgumentInitialization(
10363	Expr From, NestedNameSpecifier Qualifier, NamedDecl FoundDecl,
10364	CXXMethodDecl *Method);
10365
10366	/// PerformContextuallyConvertToBool - Perform a contextual conversion
10367	/// of the expression From to bool (C++0x [conv]p3).
10368	ExprResult PerformContextuallyConvertToBool(Expr *From);
10369
10370	/// PerformContextuallyConvertToObjCPointer - Perform a contextual
10371	/// conversion of the expression From to an Objective-C pointer type.
10372	/// Returns a valid but null ExprResult if no conversion sequence exists.
10373	ExprResult PerformContextuallyConvertToObjCPointer(Expr *From);
10374
10375	ExprResult BuildConvertedConstantExpression(Expr *From, QualType T,
10376	CCEKind CCE,
10377	NamedDecl Dest = nullptr*);
10378
10379	ExprResult CheckConvertedConstantExpression(Expr *From, QualType T,
10380	llvm::APSInt &Value, CCEKind CCE);
10381	ExprResult CheckConvertedConstantExpression(Expr *From, QualType T,
10382	APValue &Value, CCEKind CCE,
10383	NamedDecl Dest = nullptr*);
10384
10385	/// EvaluateConvertedConstantExpression - Evaluate an Expression
10386	/// That is a converted constant expression
10387	/// (which was built with BuildConvertedConstantExpression)
10388	ExprResult
10389	EvaluateConvertedConstantExpression(Expr *E, QualType T, APValue &Value,
10390	CCEKind CCE, bool RequireInt,
10391	const APValue &PreNarrowingValue);
10392
10393	/// Abstract base class used to perform a contextual implicit
10394	/// conversion from an expression to any type passing a filter.
10395	class ContextualImplicitConverter {
10396	public:
10397	bool Suppress;
10398	bool SuppressConversion;
10399
10400	ContextualImplicitConverter(bool Suppress = false,
10401	bool SuppressConversion = false)
10402	: Suppress(Suppress), SuppressConversion(SuppressConversion) {}
10403
10404	/// Determine whether the specified type is a valid destination type
10405	/// for this conversion.
10406	virtual bool match(QualType T) = `0`;
10407
10408	/// Emits a diagnostic complaining that the expression does not have
10409	/// integral or enumeration type.
10410	virtual SemaDiagnosticBuilder diagnoseNoMatch(Sema &S, SourceLocation Loc,
10411	QualType T) = `0`;
10412
10413	/// Emits a diagnostic when the expression has incomplete class type.
10414	virtual SemaDiagnosticBuilder
10415	diagnoseIncomplete(Sema &S, SourceLocation Loc, QualType T) = `0`;
10416
10417	/// Emits a diagnostic when the only matching conversion function
10418	/// is explicit.
10419	virtual SemaDiagnosticBuilder diagnoseExplicitConv(Sema &S,
10420	SourceLocation Loc,
10421	QualType T,
10422	QualType ConvTy) = `0`;
10423
10424	/// Emits a note for the explicit conversion function.
10425	virtual SemaDiagnosticBuilder
10426	noteExplicitConv(Sema &S, CXXConversionDecl *Conv, QualType ConvTy) = `0`;
10427
10428	/// Emits a diagnostic when there are multiple possible conversion
10429	/// functions.
10430	virtual SemaDiagnosticBuilder diagnoseAmbiguous(Sema &S, SourceLocation Loc,
10431	QualType T) = `0`;
10432
10433	/// Emits a note for one of the candidate conversions.
10434	virtual SemaDiagnosticBuilder
10435	noteAmbiguous(Sema &S, CXXConversionDecl *Conv, QualType ConvTy) = `0`;
10436
10437	/// Emits a diagnostic when we picked a conversion function
10438	/// (for cases when we are not allowed to pick a conversion function).
10439	virtual SemaDiagnosticBuilder diagnoseConversion(Sema &S,
10440	SourceLocation Loc,
10441	QualType T,
10442	QualType ConvTy) = `0`;
10443
10444	virtual ~ContextualImplicitConverter() {}
10445	};
10446
10447	class ICEConvertDiagnoser : public ContextualImplicitConverter {
10448	bool AllowScopedEnumerations;
10449
10450	public:
10451	ICEConvertDiagnoser(bool AllowScopedEnumerations, bool Suppress,
10452	bool SuppressConversion)
10453	: ContextualImplicitConverter (Suppress, SuppressConversion),
10454	AllowScopedEnumerations(AllowScopedEnumerations) {}
10455
10456	/// Match an integral or (possibly scoped) enumeration type.
10457	bool match(QualType T) override;
10458
10459	SemaDiagnosticBuilder diagnoseNoMatch(Sema &S, SourceLocation Loc,
10460	QualType T) override {
10461	return diagnoseNotInt(S, Loc, T);
10462	}
10463
10464	/// Emits a diagnostic complaining that the expression does not have
10465	/// integral or enumeration type.
10466	virtual SemaDiagnosticBuilder diagnoseNotInt(Sema &S, SourceLocation Loc,
10467	QualType T) = `0`;
10468	};
10469
10470	/// Perform a contextual implicit conversion.
10471	ExprResult
10472	PerformContextualImplicitConversion(SourceLocation Loc, Expr *FromE,
10473	ContextualImplicitConverter &Converter);
10474
10475	/// ReferenceCompareResult - Expresses the result of comparing two
10476	/// types (cv1 T1 and cv2 T2) to determine their compatibility for the
10477	/// purposes of initialization by reference (C++ [dcl.init.ref]p4).
10478	enum ReferenceCompareResult {
10479	/// Ref_Incompatible - The two types are incompatible, so direct
10480	/// reference binding is not possible.
10481	Ref_Incompatible = `0`,
10482	/// Ref_Related - The two types are reference-related, which means
10483	/// that their unqualified forms (T1 and T2) are either the same
10484	/// or T1 is a base class of T2.
10485	Ref_Related,
10486	/// Ref_Compatible - The two types are reference-compatible.
10487	Ref_Compatible
10488	};
10489
10490	// Fake up a scoped enumeration that still contextually converts to bool.
10491	struct ReferenceConversionsScope {
10492	/// The conversions that would be performed on an lvalue of type T2 when
10493	/// binding a reference of type T1 to it, as determined when evaluating
10494	/// whether T1 is reference-compatible with T2.
10495	enum ReferenceConversions {
10496	Qualification = `0x1`,
10497	NestedQualification = `0x2`,
10498	Function = `0x4`,
10499	DerivedToBase = `0x8`,
10500	ObjC = `0x10`,
10501	ObjCLifetime = `0x20`,
10502
10503	LLVM_MARK_AS_BITMASK_ENUM(/LargestValue=/ObjCLifetime)
10504	};
10505	};
10506	using ReferenceConversions = ReferenceConversionsScope::ReferenceConversions;
10507
10508	/// CompareReferenceRelationship - Compare the two types T1 and T2 to
10509	/// determine whether they are reference-compatible,
10510	/// reference-related, or incompatible, for use in C++ initialization by
10511	/// reference (C++ [dcl.ref.init]p4). Neither type can be a reference
10512	/// type, and the first type (T1) is the pointee type of the reference
10513	/// type being initialized.
10514	ReferenceCompareResult
10515	CompareReferenceRelationship(SourceLocation Loc, QualType T1, QualType T2,
10516	ReferenceConversions Conv = nullptr*);
10517
10518	/// AddOverloadCandidate - Adds the given function to the set of
10519	/// candidate functions, using the given function call arguments. If
10520	/// @p SuppressUserConversions, then don't allow user-defined
10521	/// conversions via constructors or conversion operators.
10522	///
10523	/// \param PartialOverloading true if we are performing "partial" overloading
10524	/// based on an incomplete set of function arguments. This feature is used by
10525	/// code completion.
10526	void AddOverloadCandidate(
10527	FunctionDecl Function, DeclAccessPair FoundDecl, ArrayRef<Expr > Args,
10528	OverloadCandidateSet &CandidateSet, bool SuppressUserConversions = false,
10529	bool PartialOverloading = false, bool AllowExplicit = true,
10530	bool AllowExplicitConversion = false,
10531	ADLCallKind IsADLCandidate = ADLCallKind::NotADL,
10532	ConversionSequenceList EarlyConversions = {},
10533	OverloadCandidateParamOrder PO = {},
10534	bool AggregateCandidateDeduction = false, bool StrictPackMatch = false);
10535
10536	/// Add all of the function declarations in the given function set to
10537	/// the overload candidate set.
10538	void AddFunctionCandidates(
10539	const UnresolvedSetImpl &Functions, ArrayRef<Expr *> Args,
10540	OverloadCandidateSet &CandidateSet,
10541	TemplateArgumentListInfo ExplicitTemplateArgs = nullptr*,
10542	bool SuppressUserConversions = false, bool PartialOverloading = false,
10543	bool FirstArgumentIsBase = false);
10544
10545	/// AddMethodCandidate - Adds a named decl (which is some kind of
10546	/// method) as a method candidate to the given overload set.
10547	void AddMethodCandidate(DeclAccessPair FoundDecl, QualType ObjectType,
10548	Expr::Classification ObjectClassification,
10549	ArrayRef<Expr *> Args,
10550	OverloadCandidateSet &CandidateSet,
10551	bool SuppressUserConversion = false,
10552	OverloadCandidateParamOrder PO = {});
10553
10554	/// AddMethodCandidate - Adds the given C++ member function to the set
10555	/// of candidate functions, using the given function call arguments
10556	/// and the object argument (@c Object). For example, in a call
10557	/// @c o.f(a1,a2), @c Object will contain @c o and @c Args will contain
10558	/// both @c a1 and @c a2. If @p SuppressUserConversions, then don't
10559	/// allow user-defined conversions via constructors or conversion
10560	/// operators.
10561	void AddMethodCandidate(CXXMethodDecl *Method, DeclAccessPair FoundDecl,
10562	CXXRecordDecl *ActingContext, QualType ObjectType,
10563	Expr::Classification ObjectClassification,
10564	ArrayRef<Expr *> Args,
10565	OverloadCandidateSet &CandidateSet,
10566	bool SuppressUserConversions = false,
10567	bool PartialOverloading = false,
10568	ConversionSequenceList EarlyConversions = {},
10569	OverloadCandidateParamOrder PO = {},
10570	bool StrictPackMatch = false);
10571
10572	/// Add a C++ member function template as a candidate to the candidate
10573	/// set, using template argument deduction to produce an appropriate member
10574	/// function template specialization.
10575	void AddMethodTemplateCandidate(
10576	FunctionTemplateDecl *MethodTmpl, DeclAccessPair FoundDecl,
10577	CXXRecordDecl *ActingContext,
10578	TemplateArgumentListInfo *ExplicitTemplateArgs, QualType ObjectType,
10579	Expr::Classification ObjectClassification, ArrayRef<Expr *> Args,
10580	OverloadCandidateSet &CandidateSet, bool SuppressUserConversions = false,
10581	bool PartialOverloading = false, OverloadCandidateParamOrder PO = {});
10582
10583	/// Add a C++ function template specialization as a candidate
10584	/// in the candidate set, using template argument deduction to produce
10585	/// an appropriate function template specialization.
10586	void AddTemplateOverloadCandidate(
10587	FunctionTemplateDecl *FunctionTemplate, DeclAccessPair FoundDecl,
10588	TemplateArgumentListInfo ExplicitTemplateArgs, ArrayRef<Expr > Args,
10589	OverloadCandidateSet &CandidateSet, bool SuppressUserConversions = false,
10590	bool PartialOverloading = false, bool AllowExplicit = true,
10591	ADLCallKind IsADLCandidate = ADLCallKind::NotADL,
10592	OverloadCandidateParamOrder PO = {},
10593	bool AggregateCandidateDeduction = false);
10594
10595	struct CheckNonDependentConversionsFlag {
10596	/// Do not consider any user-defined conversions when constructing the
10597	/// initializing sequence.
10598	bool SuppressUserConversions;
10599
10600	/// Before constructing the initializing sequence, we check whether the
10601	/// parameter type and argument type contain any user defined conversions.
10602	/// If so, do not initialize them. This effectively bypasses some undesired
10603	/// instantiation before checking constaints, which might otherwise result
10604	/// in non-SFINAE errors e.g. recursive constraints.
10605	bool OnlyInitializeNonUserDefinedConversions;
10606
10607	CheckNonDependentConversionsFlag(
10608	bool SuppressUserConversions,
10609	bool OnlyInitializeNonUserDefinedConversions)
10610	: SuppressUserConversions(SuppressUserConversions),
10611	OnlyInitializeNonUserDefinedConversions(
10612	OnlyInitializeNonUserDefinedConversions) {}
10613	};
10614
10615	/// Check that implicit conversion sequences can be formed for each argument
10616	/// whose corresponding parameter has a non-dependent type, per DR1391's
10617	/// [temp.deduct.call]p10.
10618	bool CheckNonDependentConversions(
10619	FunctionTemplateDecl *FunctionTemplate, ArrayRef<QualType> ParamTypes,
10620	ArrayRef<Expr *> Args, OverloadCandidateSet &CandidateSet,
10621	ConversionSequenceList &Conversions,
10622	CheckNonDependentConversionsFlag UserConversionFlag,
10623	CXXRecordDecl ActingContext = nullptr*, QualType ObjectType = QualType (),
10624	Expr::Classification ObjectClassification = {},
10625	OverloadCandidateParamOrder PO = {});
10626
10627	/// AddConversionCandidate - Add a C++ conversion function as a
10628	/// candidate in the candidate set (C++ [over.match.conv],
10629	/// C++ [over.match.copy]). From is the expression we're converting from,
10630	/// and ToType is the type that we're eventually trying to convert to
10631	/// (which may or may not be the same type as the type that the
10632	/// conversion function produces).
10633	void AddConversionCandidate(
10634	CXXConversionDecl *Conversion, DeclAccessPair FoundDecl,
10635	CXXRecordDecl ActingContext, Expr From, QualType ToType,
10636	OverloadCandidateSet &CandidateSet, bool AllowObjCConversionOnExplicit,
10637	bool AllowExplicit, bool AllowResultConversion = true,
10638	bool StrictPackMatch = false);
10639
10640	/// Adds a conversion function template specialization
10641	/// candidate to the overload set, using template argument deduction
10642	/// to deduce the template arguments of the conversion function
10643	/// template from the type that we are converting to (C++
10644	/// [temp.deduct.conv]).
10645	void AddTemplateConversionCandidate(
10646	FunctionTemplateDecl *FunctionTemplate, DeclAccessPair FoundDecl,
10647	CXXRecordDecl ActingContext, Expr From, QualType ToType,
10648	OverloadCandidateSet &CandidateSet, bool AllowObjCConversionOnExplicit,
10649	bool AllowExplicit, bool AllowResultConversion = true);
10650
10651	/// AddSurrogateCandidate - Adds a "surrogate" candidate function that
10652	/// converts the given @c Object to a function pointer via the
10653	/// conversion function @c Conversion, and then attempts to call it
10654	/// with the given arguments (C++ [over.call.object]p2-4). Proto is
10655	/// the type of function that we'll eventually be calling.
10656	void AddSurrogateCandidate(CXXConversionDecl *Conversion,
10657	DeclAccessPair FoundDecl,
10658	CXXRecordDecl *ActingContext,
10659	const FunctionProtoType Proto, Expr Object,
10660	ArrayRef<Expr *> Args,
10661	OverloadCandidateSet &CandidateSet);
10662
10663	/// Add all of the non-member operator function declarations in the given
10664	/// function set to the overload candidate set.
10665	void AddNonMemberOperatorCandidates(
10666	const UnresolvedSetImpl &Functions, ArrayRef<Expr *> Args,
10667	OverloadCandidateSet &CandidateSet,
10668	TemplateArgumentListInfo ExplicitTemplateArgs = nullptr*);
10669
10670	/// Add overload candidates for overloaded operators that are
10671	/// member functions.
10672	///
10673	/// Add the overloaded operator candidates that are member functions
10674	/// for the operator Op that was used in an operator expression such
10675	/// as "x Op y". , Args/NumArgs provides the operator arguments, and
10676	/// CandidateSet will store the added overload candidates. (C++
10677	/// [over.match.oper]).
10678	void AddMemberOperatorCandidates(OverloadedOperatorKind Op,
10679	SourceLocation OpLoc, ArrayRef<Expr *> Args,
10680	OverloadCandidateSet &CandidateSet,
10681	OverloadCandidateParamOrder PO = {});
10682
10683	/// AddBuiltinCandidate - Add a candidate for a built-in
10684	/// operator. ResultTy and ParamTys are the result and parameter types
10685	/// of the built-in candidate, respectively. Args and NumArgs are the
10686	/// arguments being passed to the candidate. IsAssignmentOperator
10687	/// should be true when this built-in candidate is an assignment
10688	/// operator. NumContextualBoolArguments is the number of arguments
10689	/// (at the beginning of the argument list) that will be contextually
10690	/// converted to bool.
10691	void AddBuiltinCandidate(QualType ParamTys, ArrayRef<Expr > Args,
10692	OverloadCandidateSet &CandidateSet,
10693	bool IsAssignmentOperator = false,
10694	unsigned NumContextualBoolArguments = `0`);
10695
10696	/// AddBuiltinOperatorCandidates - Add the appropriate built-in
10697	/// operator overloads to the candidate set (C++ [over.built]), based
10698	/// on the operator @p Op and the arguments given. For example, if the
10699	/// operator is a binary '+', this routine might add "int
10700	/// operator+(int, int)" to cover integer addition.
10701	void AddBuiltinOperatorCandidates(OverloadedOperatorKind Op,
10702	SourceLocation OpLoc, ArrayRef<Expr *> Args,
10703	OverloadCandidateSet &CandidateSet);
10704
10705	/// Add function candidates found via argument-dependent lookup
10706	/// to the set of overloading candidates.
10707	///
10708	/// This routine performs argument-dependent name lookup based on the
10709	/// given function name (which may also be an operator name) and adds
10710	/// all of the overload candidates found by ADL to the overload
10711	/// candidate set (C++ [basic.lookup.argdep]).
10712	void AddArgumentDependentLookupCandidates(
10713	DeclarationName Name, SourceLocation Loc, ArrayRef<Expr *> Args,
10714	TemplateArgumentListInfo *ExplicitTemplateArgs,
10715	OverloadCandidateSet &CandidateSet, bool PartialOverloading = false);
10716
10717	/// Check the enable_if expressions on the given function. Returns the first
10718	/// failing attribute, or NULL if they were all successful.
10719	EnableIfAttr CheckEnableIf(FunctionDecl Function, SourceLocation CallLoc,
10720	ArrayRef<Expr *> Args,
10721	bool MissingImplicitThis = false);
10722
10723	/// Emit diagnostics for the diagnose_if attributes on Function, ignoring any
10724	/// non-ArgDependent DiagnoseIfAttrs.
10725	///
10726	/// Argument-dependent diagnose_if attributes should be checked each time a
10727	/// function is used as a direct callee of a function call.
10728	///
10729	/// Returns true if any errors were emitted.
10730	bool diagnoseArgDependentDiagnoseIfAttrs(const FunctionDecl *Function,
10731	const Expr *ThisArg,
10732	ArrayRef<const Expr *> Args,
10733	SourceLocation Loc);
10734
10735	/// Emit diagnostics for the diagnose_if attributes on Function, ignoring any
10736	/// ArgDependent DiagnoseIfAttrs.
10737	///
10738	/// Argument-independent diagnose_if attributes should be checked on every use
10739	/// of a function.
10740	///
10741	/// Returns true if any errors were emitted.
10742	bool diagnoseArgIndependentDiagnoseIfAttrs(const NamedDecl *ND,
10743	SourceLocation Loc);
10744
10745	/// Determine if \p A and \p B are equivalent internal linkage declarations
10746	/// from different modules, and thus an ambiguity error can be downgraded to
10747	/// an extension warning.
10748	bool isEquivalentInternalLinkageDeclaration(const NamedDecl *A,
10749	const NamedDecl *B);
10750	void diagnoseEquivalentInternalLinkageDeclarations(
10751	SourceLocation Loc, const NamedDecl *D,
10752	ArrayRef<const NamedDecl *> Equiv);
10753
10754	// Emit as a 'note' the specific overload candidate
10755	void NoteOverloadCandidate(
10756	const NamedDecl Found, const* FunctionDecl *Fn,
10757	OverloadCandidateRewriteKind RewriteKind = OverloadCandidateRewriteKind(),
10758	QualType DestType = QualType (), bool TakingAddress = false);
10759
10760	// Emit as a series of 'note's all template and non-templates identified by
10761	// the expression Expr
10762	void NoteAllOverloadCandidates(Expr *E, QualType DestType = QualType (),
10763	bool TakingAddress = false);
10764
10765	/// Returns whether the given function's address can be taken or not,
10766	/// optionally emitting a diagnostic if the address can't be taken.
10767	///
10768	/// Returns false if taking the address of the function is illegal.
10769	bool checkAddressOfFunctionIsAvailable(const FunctionDecl *Function,
10770	bool Complain = false,
10771	SourceLocation Loc = SourceLocation ());
10772
10773	// [PossiblyAFunctionType] --> [Return]
10774	// NonFunctionType --> NonFunctionType
10775	// R (A) --> R(A)
10776	// R ()(A) --> R (A)*
10777	// R (&)(A) --> R (A)
10778	// R (S::)(A) --> R (A)*
10779	QualType ExtractUnqualifiedFunctionType(QualType PossiblyAFunctionType);
10780
10781	/// ResolveAddressOfOverloadedFunction - Try to resolve the address of
10782	/// an overloaded function (C++ [over.over]), where @p From is an
10783	/// expression with overloaded function type and @p ToType is the type
10784	/// we're trying to resolve to. For example:
10785	///
10786	/// @code
10787	/// int f(double);
10788	/// int f(int);
10789	///
10790	/// int (pfd)(double) = f; // selects f(double)*
10791	/// @endcode
10792	///
10793	/// This routine returns the resulting FunctionDecl if it could be
10794	/// resolved, and NULL otherwise. When @p Complain is true, this
10795	/// routine will emit diagnostics if there is an error.
10796	FunctionDecl *
10797	ResolveAddressOfOverloadedFunction(Expr *AddressOfExpr, QualType TargetType,
10798	bool Complain, DeclAccessPair &Found,
10799	bool pHadMultipleCandidates = nullptr*);
10800
10801	/// Given an expression that refers to an overloaded function, try to
10802	/// resolve that function to a single function that can have its address
10803	/// taken. This will modify `Pair` iff it returns non-null.
10804	///
10805	/// This routine can only succeed if from all of the candidates in the
10806	/// overload set for SrcExpr that can have their addresses taken, there is one
10807	/// candidate that is more constrained than the rest.
10808	FunctionDecl *
10809	resolveAddressOfSingleOverloadCandidate(Expr *E, DeclAccessPair &FoundResult);
10810
10811	/// Given an overloaded function, tries to turn it into a non-overloaded
10812	/// function reference using resolveAddressOfSingleOverloadCandidate. This
10813	/// will perform access checks, diagnose the use of the resultant decl, and,
10814	/// if requested, potentially perform a function-to-pointer decay.
10815	///
10816	/// Returns false if resolveAddressOfSingleOverloadCandidate fails.
10817	/// Otherwise, returns true. This may emit diagnostics and return true.
10818	bool resolveAndFixAddressOfSingleOverloadCandidate(
10819	ExprResult &SrcExpr, bool DoFunctionPointerConversion = false);
10820
10821	/// Given an expression that refers to an overloaded function, try to
10822	/// resolve that overloaded function expression down to a single function.
10823	///
10824	/// This routine can only resolve template-ids that refer to a single function
10825	/// template, where that template-id refers to a single template whose
10826	/// template arguments are either provided by the template-id or have
10827	/// defaults, as described in C++0x [temp.arg.explicit]p3.
10828	///
10829	/// If no template-ids are found, no diagnostics are emitted and NULL is
10830	/// returned.
10831	FunctionDecl *ResolveSingleFunctionTemplateSpecialization(
10832	OverloadExpr ovl, bool* Complain = false, DeclAccessPair Found = nullptr*,
10833	TemplateSpecCandidateSet FailedTSC = nullptr*,
10834	bool ForTypeDeduction = false);
10835
10836	// Resolve and fix an overloaded expression that can be resolved
10837	// because it identifies a single function template specialization.
10838	//
10839	// Last three arguments should only be supplied if Complain = true
10840	//
10841	// Return true if it was logically possible to so resolve the
10842	// expression, regardless of whether or not it succeeded. Always
10843	// returns true if 'complain' is set.
10844	bool ResolveAndFixSingleFunctionTemplateSpecialization(
10845	ExprResult &SrcExpr, bool DoFunctionPointerConversion = false,
10846	bool Complain = false, SourceRange OpRangeForComplaining = SourceRange (),
10847	QualType DestTypeForComplaining = QualType (),
10848	unsigned DiagIDForComplaining = `0`);
10849
10850	/// Add the overload candidates named by callee and/or found by argument
10851	/// dependent lookup to the given overload set.
10852	void AddOverloadedCallCandidates(UnresolvedLookupExpr *ULE,
10853	ArrayRef<Expr *> Args,
10854	OverloadCandidateSet &CandidateSet,
10855	bool PartialOverloading = false);
10856
10857	/// Add the call candidates from the given set of lookup results to the given
10858	/// overload set. Non-function lookup results are ignored.
10859	void AddOverloadedCallCandidates(
10860	LookupResult &R, TemplateArgumentListInfo *ExplicitTemplateArgs,
10861	ArrayRef<Expr *> Args, OverloadCandidateSet &CandidateSet);
10862
10863	// An enum used to represent the different possible results of building a
10864	// range-based for loop.
10865	enum ForRangeStatus {
10866	FRS_Success,
10867	FRS_NoViableFunction,
10868	FRS_DiagnosticIssued
10869	};
10870
10871	/// Build a call to 'begin' or 'end' for a C++11 for-range statement. If the
10872	/// given LookupResult is non-empty, it is assumed to describe a member which
10873	/// will be invoked. Otherwise, the function will be found via argument
10874	/// dependent lookup.
10875	/// CallExpr is set to a valid expression and FRS_Success returned on success,
10876	/// otherwise CallExpr is set to ExprError() and some non-success value
10877	/// is returned.
10878	ForRangeStatus BuildForRangeBeginEndCall(SourceLocation Loc,
10879	SourceLocation RangeLoc,
10880	const DeclarationNameInfo &NameInfo,
10881	LookupResult &MemberLookup,
10882	OverloadCandidateSet *CandidateSet,
10883	Expr Range, ExprResult CallExpr);
10884
10885	/// BuildOverloadedCallExpr - Given the call expression that calls Fn
10886	/// (which eventually refers to the declaration Func) and the call
10887	/// arguments Args/NumArgs, attempt to resolve the function call down
10888	/// to a specific function. If overload resolution succeeds, returns
10889	/// the call expression produced by overload resolution.
10890	/// Otherwise, emits diagnostics and returns ExprError.
10891	ExprResult BuildOverloadedCallExpr(
10892	Scope S, Expr Fn, UnresolvedLookupExpr *ULE, SourceLocation LParenLoc,
10893	MultiExprArg Args, SourceLocation RParenLoc, Expr *ExecConfig,
10894	bool AllowTypoCorrection = true, bool CalleesAddressIsTaken = false);
10895
10896	/// Constructs and populates an OverloadedCandidateSet from
10897	/// the given function.
10898	/// \returns true when an the ExprResult output parameter has been set.
10899	bool buildOverloadedCallSet(Scope S, Expr Fn, UnresolvedLookupExpr *ULE,
10900	MultiExprArg Args, SourceLocation RParenLoc,
10901	OverloadCandidateSet *CandidateSet,
10902	ExprResult *Result);
10903
10904	ExprResult CreateUnresolvedLookupExpr(CXXRecordDecl *NamingClass,
10905	NestedNameSpecifierLoc NNSLoc,
10906	DeclarationNameInfo DNI,
10907	const UnresolvedSetImpl &Fns,
10908	bool PerformADL = true);
10909
10910	/// Create a unary operation that may resolve to an overloaded
10911	/// operator.
10912	///
10913	/// \param OpLoc The location of the operator itself (e.g., '').*
10914	///
10915	/// \param Opc The UnaryOperatorKind that describes this operator.
10916	///
10917	/// \param Fns The set of non-member functions that will be
10918	/// considered by overload resolution. The caller needs to build this
10919	/// set based on the context using, e.g.,
10920	/// LookupOverloadedOperatorName() and ArgumentDependentLookup(). This
10921	/// set should not contain any member functions; those will be added
10922	/// by CreateOverloadedUnaryOp().
10923	///
10924	/// \param Input The input argument.
10925	ExprResult CreateOverloadedUnaryOp(SourceLocation OpLoc,
10926	UnaryOperatorKind Opc,
10927	const UnresolvedSetImpl &Fns, Expr *input,
10928	bool RequiresADL = true);
10929
10930	/// Perform lookup for an overloaded binary operator.
10931	void LookupOverloadedBinOp(OverloadCandidateSet &CandidateSet,
10932	OverloadedOperatorKind Op,
10933	const UnresolvedSetImpl &Fns,
10934	ArrayRef<Expr > Args, bool* RequiresADL = true);
10935
10936	/// Create a binary operation that may resolve to an overloaded
10937	/// operator.
10938	///
10939	/// \param OpLoc The location of the operator itself (e.g., '+').
10940	///
10941	/// \param Opc The BinaryOperatorKind that describes this operator.
10942	///
10943	/// \param Fns The set of non-member functions that will be
10944	/// considered by overload resolution. The caller needs to build this
10945	/// set based on the context using, e.g.,
10946	/// LookupOverloadedOperatorName() and ArgumentDependentLookup(). This
10947	/// set should not contain any member functions; those will be added
10948	/// by CreateOverloadedBinOp().
10949	///
10950	/// \param LHS Left-hand argument.
10951	/// \param RHS Right-hand argument.
10952	/// \param PerformADL Whether to consider operator candidates found by ADL.
10953	/// \param AllowRewrittenCandidates Whether to consider candidates found by
10954	/// C++20 operator rewrites.
10955	/// \param DefaultedFn If we are synthesizing a defaulted operator function,
10956	/// the function in question. Such a function is never a candidate in
10957	/// our overload resolution. This also enables synthesizing a three-way
10958	/// comparison from < and == as described in C++20 [class.spaceship]p1.
10959	ExprResult CreateOverloadedBinOp(SourceLocation OpLoc, BinaryOperatorKind Opc,
10960	const UnresolvedSetImpl &Fns, Expr *LHS,
10961	Expr RHS, bool* RequiresADL = true,
10962	bool AllowRewrittenCandidates = true,
10963	FunctionDecl DefaultedFn = nullptr*);
10964	ExprResult BuildSynthesizedThreeWayComparison(SourceLocation OpLoc,
10965	const UnresolvedSetImpl &Fns,
10966	Expr LHS, Expr RHS,
10967	FunctionDecl *DefaultedFn);
10968
10969	ExprResult CreateOverloadedArraySubscriptExpr(SourceLocation LLoc,
10970	SourceLocation RLoc, Expr *Base,
10971	MultiExprArg Args);
10972
10973	/// BuildCallToMemberFunction - Build a call to a member
10974	/// function. MemExpr is the expression that refers to the member
10975	/// function (and includes the object parameter), Args/NumArgs are the
10976	/// arguments to the function call (not including the object
10977	/// parameter). The caller needs to validate that the member
10978	/// expression refers to a non-static member function or an overloaded
10979	/// member function.
10980	ExprResult BuildCallToMemberFunction(
10981	Scope S, Expr MemExpr, SourceLocation LParenLoc, MultiExprArg Args,
10982	SourceLocation RParenLoc, Expr ExecConfig = nullptr*,
10983	bool IsExecConfig = false, bool AllowRecovery = false);
10984
10985	/// BuildCallToObjectOfClassType - Build a call to an object of class
10986	/// type (C++ [over.call.object]), which can end up invoking an
10987	/// overloaded function call operator (@c operator()) or performing a
10988	/// user-defined conversion on the object argument.
10989	ExprResult BuildCallToObjectOfClassType(Scope S, Expr Object,
10990	SourceLocation LParenLoc,
10991	MultiExprArg Args,
10992	SourceLocation RParenLoc);
10993
10994	/// BuildOverloadedArrowExpr - Build a call to an overloaded @c operator->
10995	/// (if one exists), where @c Base is an expression of class type and
10996	/// @c Member is the name of the member we're trying to find.
10997	ExprResult BuildOverloadedArrowExpr(Scope S, Expr Base,
10998	SourceLocation OpLoc,
10999	bool NoArrowOperatorFound = nullptr*);
11000
11001	ExprResult BuildCXXMemberCallExpr(Expr Exp, NamedDecl FoundDecl,
11002	CXXConversionDecl *Method,
11003	bool HadMultipleCandidates);
11004
11005	/// BuildLiteralOperatorCall - Build a UserDefinedLiteral by creating a call
11006	/// to a literal operator described by the provided lookup results.
11007	ExprResult BuildLiteralOperatorCall(
11008	LookupResult &R, DeclarationNameInfo &SuffixInfo, ArrayRef<Expr *> Args,
11009	SourceLocation LitEndLoc,
11010	TemplateArgumentListInfo ExplicitTemplateArgs = nullptr*);
11011
11012	/// FixOverloadedFunctionReference - E is an expression that refers to
11013	/// a C++ overloaded function (possibly with some parentheses and
11014	/// perhaps a '&' around it). We have resolved the overloaded function
11015	/// to the function declaration Fn, so patch up the expression E to
11016	/// refer (possibly indirectly) to Fn. Returns the new expr.
11017	ExprResult FixOverloadedFunctionReference(Expr *E, DeclAccessPair FoundDecl,
11018	FunctionDecl *Fn);
11019	ExprResult FixOverloadedFunctionReference(ExprResult,
11020	DeclAccessPair FoundDecl,
11021	FunctionDecl *Fn);
11022
11023	/// - Returns a selector which best matches given argument list or
11024	/// nullptr if none could be found
11025	ObjCMethodDecl *SelectBestMethod(Selector Sel, MultiExprArg Args,
11026	bool IsInstance,
11027	SmallVectorImpl<ObjCMethodDecl *> &Methods);
11028
11029	///@}
11030
11031	//
11032	//
11033	// -------------------------------------------------------------------------
11034	//
11035	//
11036
11037	/// \name Statements
11038	/// Implementations are in SemaStmt.cpp
11039	///@{
11040
11041	public:
11042	/// Stack of active SEH __finally scopes. Can be empty.
11043	SmallVector<Scope *, `2`> CurrentSEHFinally;
11044
11045	/// Stack of '_Defer' statements that are currently being parsed, as well
11046	/// as the locations of their '_Defer' keywords. Can be empty.
11047	SmallVector<std::pair<Scope *, SourceLocation>, `2`> CurrentDefer;
11048
11049	StmtResult ActOnExprStmt(ExprResult Arg, bool DiscardedValue = true);
11050	StmtResult ActOnExprStmtError();
11051
11052	StmtResult ActOnNullStmt(SourceLocation SemiLoc,
11053	bool HasLeadingEmptyMacro = false);
11054
11055	StmtResult ActOnDeclStmt(DeclGroupPtrTy Decl, SourceLocation StartLoc,
11056	SourceLocation EndLoc);
11057	void ActOnForEachDeclStmt(DeclGroupPtrTy Decl);
11058
11059	/// DiagnoseUnusedExprResult - If the statement passed in is an expression
11060	/// whose result is unused, warn.
11061	void DiagnoseUnusedExprResult(const Stmt S, unsigned* DiagID);
11062
11063	void ActOnStartOfCompoundStmt(bool IsStmtExpr);
11064	void ActOnAfterCompoundStatementLeadingPragmas();
11065	void ActOnFinishOfCompoundStmt();
11066	StmtResult ActOnCompoundStmt(SourceLocation L, SourceLocation R,
11067	ArrayRef<Stmt > Elts, bool* isStmtExpr);
11068
11069	sema::CompoundScopeInfo &getCurCompoundScope() const;
11070
11071	ExprResult ActOnCaseExpr(SourceLocation CaseLoc, ExprResult Val);
11072	StmtResult ActOnCaseStmt(SourceLocation CaseLoc, ExprResult LHS,
11073	SourceLocation DotDotDotLoc, ExprResult RHS,
11074	SourceLocation ColonLoc);
11075
11076	/// ActOnCaseStmtBody - This installs a statement as the body of a case.
11077	void ActOnCaseStmtBody(Stmt CaseStmt, Stmt SubStmt);
11078
11079	StmtResult ActOnDefaultStmt(SourceLocation DefaultLoc,
11080	SourceLocation ColonLoc, Stmt *SubStmt,
11081	Scope *CurScope);
11082	StmtResult ActOnLabelStmt(SourceLocation IdentLoc, LabelDecl *TheDecl,
11083	SourceLocation ColonLoc, Stmt *SubStmt);
11084
11085	StmtResult BuildAttributedStmt(SourceLocation AttrsLoc,
11086	ArrayRef<const Attr > Attrs, Stmt SubStmt);
11087	StmtResult ActOnAttributedStmt(const ParsedAttributes &AttrList,
11088	Stmt *SubStmt);
11089
11090	/// Check whether the given statement can have musttail applied to it,
11091	/// issuing a diagnostic and returning false if not. In the success case,
11092	/// the statement is rewritten to remove implicit nodes from the return
11093	/// value.
11094	bool checkAndRewriteMustTailAttr(Stmt St, const* Attr &MTA);
11095
11096	StmtResult ActOnIfStmt(SourceLocation IfLoc, IfStatementKind StatementKind,
11097	SourceLocation LParenLoc, Stmt *InitStmt,
11098	ConditionResult Cond, SourceLocation RParenLoc,
11099	Stmt ThenVal, SourceLocation ElseLoc, Stmt ElseVal);
11100	StmtResult BuildIfStmt(SourceLocation IfLoc, IfStatementKind StatementKind,
11101	SourceLocation LParenLoc, Stmt *InitStmt,
11102	ConditionResult Cond, SourceLocation RParenLoc,
11103	Stmt ThenVal, SourceLocation ElseLoc, Stmt ElseVal);
11104
11105	ExprResult CheckSwitchCondition(SourceLocation SwitchLoc, Expr *Cond);
11106
11107	StmtResult ActOnStartOfSwitchStmt(SourceLocation SwitchLoc,
11108	SourceLocation LParenLoc, Stmt *InitStmt,
11109	ConditionResult Cond,
11110	SourceLocation RParenLoc);
11111	StmtResult ActOnFinishSwitchStmt(SourceLocation SwitchLoc, Stmt *Switch,
11112	Stmt *Body);
11113
11114	/// DiagnoseAssignmentEnum - Warn if assignment to enum is a constant
11115	/// integer not in the range of enum values.
11116	void DiagnoseAssignmentEnum(QualType DstType, QualType SrcType,
11117	Expr *SrcExpr);
11118
11119	StmtResult ActOnWhileStmt(SourceLocation WhileLoc, SourceLocation LParenLoc,
11120	ConditionResult Cond, SourceLocation RParenLoc,
11121	Stmt *Body);
11122	StmtResult ActOnDoStmt(SourceLocation DoLoc, Stmt *Body,
11123	SourceLocation WhileLoc, SourceLocation CondLParen,
11124	Expr *Cond, SourceLocation CondRParen);
11125
11126	StmtResult ActOnForStmt(SourceLocation ForLoc, SourceLocation LParenLoc,
11127	Stmt *First, ConditionResult Second,
11128	FullExprArg Third, SourceLocation RParenLoc,
11129	Stmt *Body);
11130
11131	/// In an Objective C collection iteration statement:
11132	/// for (x in y)
11133	/// x can be an arbitrary l-value expression. Bind it up as a
11134	/// full-expression.
11135	StmtResult ActOnForEachLValueExpr(Expr *E);
11136
11137	enum BuildForRangeKind {
11138	/// Initial building of a for-range statement.
11139	BFRK_Build,
11140	/// Instantiation or recovery rebuild of a for-range statement. Don't
11141	/// attempt any typo-correction.
11142	BFRK_Rebuild,
11143	/// Determining whether a for-range statement could be built. Avoid any
11144	/// unnecessary or irreversible actions.
11145	BFRK_Check
11146	};
11147
11148	/// ActOnCXXForRangeStmt - Check and build a C++11 for-range statement.
11149	///
11150	/// C++11 [stmt.ranged]:
11151	/// A range-based for statement is equivalent to
11152	///
11153	/// {
11154	/// auto && __range = range-init;
11155	/// for ( auto __begin = begin-expr,
11156	/// __end = end-expr;
11157	/// __begin != __end;
11158	/// ++__begin ) {
11159	/// for-range-declaration = __begin;*
11160	/// statement
11161	/// }
11162	/// }
11163	///
11164	/// The body of the loop is not available yet, since it cannot be analysed
11165	/// until we have determined the type of the for-range-declaration.
11166	StmtResult ActOnCXXForRangeStmt(
11167	Scope *S, SourceLocation ForLoc, SourceLocation CoawaitLoc,
11168	Stmt InitStmt, Stmt LoopVar, SourceLocation ColonLoc, Expr *Collection,
11169	SourceLocation RParenLoc, BuildForRangeKind Kind,
11170	ArrayRef<MaterializeTemporaryExpr *> LifetimeExtendTemps = {});
11171
11172	/// BuildCXXForRangeStmt - Build or instantiate a C++11 for-range statement.
11173	StmtResult BuildCXXForRangeStmt(
11174	SourceLocation ForLoc, SourceLocation CoawaitLoc, Stmt *InitStmt,
11175	SourceLocation ColonLoc, Stmt RangeDecl, Stmt Begin, Stmt *End,
11176	Expr Cond, Expr Inc, Stmt *LoopVarDecl, SourceLocation RParenLoc,
11177	BuildForRangeKind Kind,
11178	ArrayRef<MaterializeTemporaryExpr *> LifetimeExtendTemps = {});
11179
11180	/// FinishCXXForRangeStmt - Attach the body to a C++0x for-range statement.
11181	/// This is a separate step from ActOnCXXForRangeStmt because analysis of the
11182	/// body cannot be performed until after the type of the range variable is
11183	/// determined.
11184	StmtResult FinishCXXForRangeStmt(Stmt ForRange, Stmt Body);
11185
11186	StmtResult ActOnGotoStmt(SourceLocation GotoLoc, SourceLocation LabelLoc,
11187	LabelDecl *TheDecl);
11188	StmtResult ActOnIndirectGotoStmt(SourceLocation GotoLoc,
11189	SourceLocation StarLoc, Expr *DestExp);
11190	StmtResult ActOnContinueStmt(SourceLocation ContinueLoc, Scope *CurScope,
11191	LabelDecl *Label, SourceLocation LabelLoc);
11192	StmtResult ActOnBreakStmt(SourceLocation BreakLoc, Scope *CurScope,
11193	LabelDecl *Label, SourceLocation LabelLoc);
11194
11195	void ActOnStartOfDeferStmt(SourceLocation DeferLoc, Scope *CurScope);
11196	void ActOnDeferStmtError(Scope *CurScope);
11197	StmtResult ActOnEndOfDeferStmt(Stmt Body, Scope CurScope);
11198
11199	struct NamedReturnInfo {
11200	const VarDecl *Candidate;
11201
11202	enum Status : uint8_t { None, MoveEligible, MoveEligibleAndCopyElidable };
11203	Status S;
11204
11205	bool isMoveEligible() const { return S != None; };
11206	bool isCopyElidable() const { return S == MoveEligibleAndCopyElidable; }
11207	};
11208	enum class SimplerImplicitMoveMode { ForceOff, Normal, ForceOn };
11209
11210	/// Determine whether the given expression might be move-eligible or
11211	/// copy-elidable in either a (co_)return statement or throw expression,
11212	/// without considering function return type, if applicable.
11213	///
11214	/// \param E The expression being returned from the function or block,
11215	/// being thrown, or being co_returned from a coroutine. This expression
11216	/// might be modified by the implementation.
11217	///
11218	/// \param Mode Overrides detection of current language mode
11219	/// and uses the rules for C++23.
11220	///
11221	/// \returns An aggregate which contains the Candidate and isMoveEligible
11222	/// and isCopyElidable methods. If Candidate is non-null, it means
11223	/// isMoveEligible() would be true under the most permissive language
11224	/// standard.
11225	NamedReturnInfo getNamedReturnInfo(
11226	Expr *&E, SimplerImplicitMoveMode Mode = SimplerImplicitMoveMode::Normal);
11227
11228	/// Determine whether the given NRVO candidate variable is move-eligible or
11229	/// copy-elidable, without considering function return type.
11230	///
11231	/// \param VD The NRVO candidate variable.
11232	///
11233	/// \returns An aggregate which contains the Candidate and isMoveEligible
11234	/// and isCopyElidable methods. If Candidate is non-null, it means
11235	/// isMoveEligible() would be true under the most permissive language
11236	/// standard.
11237	NamedReturnInfo getNamedReturnInfo(const VarDecl *VD);
11238
11239	/// Updates given NamedReturnInfo's move-eligible and
11240	/// copy-elidable statuses, considering the function
11241	/// return type criteria as applicable to return statements.
11242	///
11243	/// \param Info The NamedReturnInfo object to update.
11244	///
11245	/// \param ReturnType This is the return type of the function.
11246	/// \returns The copy elision candidate, in case the initial return expression
11247	/// was copy elidable, or nullptr otherwise.
11248	const VarDecl *getCopyElisionCandidate(NamedReturnInfo &Info,
11249	QualType ReturnType);
11250
11251	/// Perform the initialization of a potentially-movable value, which
11252	/// is the result of return value.
11253	///
11254	/// This routine implements C++20 [class.copy.elision]p3, which attempts to
11255	/// treat returned lvalues as rvalues in certain cases (to prefer move
11256	/// construction), then falls back to treating them as lvalues if that failed.
11257	ExprResult
11258	PerformMoveOrCopyInitialization(const InitializedEntity &Entity,
11259	const NamedReturnInfo &NRInfo, Expr *Value,
11260	bool SupressSimplerImplicitMoves = false);
11261
11262	TypeLoc getReturnTypeLoc(FunctionDecl FD) const*;
11263
11264	/// Deduce the return type for a function from a returned expression, per
11265	/// C++1y [dcl.spec.auto]p6.
11266	bool DeduceFunctionTypeFromReturnExpr(FunctionDecl *FD,
11267	SourceLocation ReturnLoc, Expr *RetExpr,
11268	const AutoType *AT);
11269
11270	StmtResult ActOnReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp,
11271	Scope *CurScope);
11272	StmtResult BuildReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp,
11273	bool AllowRecovery = false);
11274
11275	/// ActOnCapScopeReturnStmt - Utility routine to type-check return statements
11276	/// for capturing scopes.
11277	StmtResult ActOnCapScopeReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp,
11278	NamedReturnInfo &NRInfo,
11279	bool SupressSimplerImplicitMoves);
11280
11281	/// ActOnCXXCatchBlock - Takes an exception declaration and a handler block
11282	/// and creates a proper catch handler from them.
11283	StmtResult ActOnCXXCatchBlock(SourceLocation CatchLoc, Decl *ExDecl,
11284	Stmt *HandlerBlock);
11285
11286	/// ActOnCXXTryBlock - Takes a try compound-statement and a number of
11287	/// handlers and creates a try statement from them.
11288	StmtResult ActOnCXXTryBlock(SourceLocation TryLoc, Stmt *TryBlock,
11289	ArrayRef<Stmt *> Handlers);
11290
11291	void DiagnoseExceptionUse(SourceLocation Loc, bool IsTry);
11292
11293	StmtResult ActOnSEHTryBlock(bool IsCXXTry, // try (true) or __try (false) ?
11294	SourceLocation TryLoc, Stmt *TryBlock,
11295	Stmt *Handler);
11296	StmtResult ActOnSEHExceptBlock(SourceLocation Loc, Expr *FilterExpr,
11297	Stmt *Block);
11298	void ActOnStartSEHFinallyBlock();
11299	void ActOnAbortSEHFinallyBlock();
11300	StmtResult ActOnFinishSEHFinallyBlock(SourceLocation Loc, Stmt *Block);
11301	StmtResult ActOnSEHLeaveStmt(SourceLocation Loc, Scope *CurScope);
11302
11303	StmtResult BuildMSDependentExistsStmt(SourceLocation KeywordLoc,
11304	bool IsIfExists,
11305	NestedNameSpecifierLoc QualifierLoc,
11306	DeclarationNameInfo NameInfo,
11307	Stmt *Nested);
11308	StmtResult ActOnMSDependentExistsStmt(SourceLocation KeywordLoc,
11309	bool IsIfExists, CXXScopeSpec &SS,
11310	UnqualifiedId &Name, Stmt *Nested);
11311
11312	void ActOnCapturedRegionStart(SourceLocation Loc, Scope *CurScope,
11313	CapturedRegionKind Kind, unsigned NumParams);
11314	typedef std::pair<StringRef, QualType> CapturedParamNameType;
11315	void ActOnCapturedRegionStart(SourceLocation Loc, Scope *CurScope,
11316	CapturedRegionKind Kind,
11317	ArrayRef<CapturedParamNameType> Params,
11318	unsigned OpenMPCaptureLevel = `0`);
11319	StmtResult ActOnCapturedRegionEnd(Stmt *S);
11320	void ActOnCapturedRegionError();
11321	RecordDecl CreateCapturedStmtRecordDecl(CapturedDecl &CD,
11322	SourceLocation Loc,
11323	unsigned NumParams);
11324
11325	private:
11326	/// Check whether the given statement can have musttail applied to it,
11327	/// issuing a diagnostic and returning false if not.
11328	bool checkMustTailAttr(const Stmt St, const* Attr &MTA);
11329
11330	/// Check if the given expression contains 'break' or 'continue'
11331	/// statement that produces control flow different from GCC.
11332	void CheckBreakContinueBinding(Expr *E);
11333
11334	///@}
11335
11336	//
11337	//
11338	// -------------------------------------------------------------------------
11339	//
11340	//
11341
11342	/// \name `inline asm` Statement
11343	/// Implementations are in SemaStmtAsm.cpp
11344	///@{
11345
11346	public:
11347	ExprResult ActOnGCCAsmStmtString(Expr Stm, bool* ForAsmLabel);
11348	StmtResult ActOnGCCAsmStmt(SourceLocation AsmLoc, bool IsSimple,
11349	bool IsVolatile, unsigned NumOutputs,
11350	unsigned NumInputs, IdentifierInfo **Names,
11351	MultiExprArg Constraints, MultiExprArg Exprs,
11352	Expr *AsmString, MultiExprArg Clobbers,
11353	unsigned NumLabels, SourceLocation RParenLoc);
11354
11355	void FillInlineAsmIdentifierInfo(Expr *Res,
11356	llvm::InlineAsmIdentifierInfo &Info);
11357	ExprResult LookupInlineAsmIdentifier(CXXScopeSpec &SS,
11358	SourceLocation TemplateKWLoc,
11359	UnqualifiedId &Id,
11360	bool IsUnevaluatedContext);
11361	bool LookupInlineAsmField(StringRef Base, StringRef Member, unsigned &Offset,
11362	SourceLocation AsmLoc);
11363	ExprResult LookupInlineAsmVarDeclField(Expr *RefExpr, StringRef Member,
11364	SourceLocation AsmLoc);
11365	StmtResult ActOnMSAsmStmt(SourceLocation AsmLoc, SourceLocation LBraceLoc,
11366	ArrayRef<Token> AsmToks, StringRef AsmString,
11367	unsigned NumOutputs, unsigned NumInputs,
11368	ArrayRef<StringRef> Constraints,
11369	ArrayRef<StringRef> Clobbers,
11370	ArrayRef<Expr *> Exprs, SourceLocation EndLoc);
11371	LabelDecl *GetOrCreateMSAsmLabel(StringRef ExternalLabelName,
11372	SourceLocation Location, bool AlwaysCreate);
11373
11374	///@}
11375
11376	//
11377	//
11378	// -------------------------------------------------------------------------
11379	//
11380	//
11381
11382	/// \name Statement Attribute Handling
11383	/// Implementations are in SemaStmtAttr.cpp
11384	///@{
11385
11386	public:
11387	bool CheckNoInlineAttr(const Stmt OrigSt, const* Stmt *CurSt,
11388	const AttributeCommonInfo &A);
11389	bool CheckAlwaysInlineAttr(const Stmt OrigSt, const* Stmt *CurSt,
11390	const AttributeCommonInfo &A);
11391
11392	CodeAlignAttr BuildCodeAlignAttr(const* AttributeCommonInfo &CI, Expr *E);
11393	bool CheckRebuiltStmtAttributes(ArrayRef<const Attr *> Attrs);
11394
11395	/// Process the attributes before creating an attributed statement. Returns
11396	/// the semantic attributes that have been processed.
11397	void ProcessStmtAttributes(Stmt Stmt, const* ParsedAttributes &InAttrs,
11398	SmallVectorImpl<const Attr *> &OutAttrs);
11399
11400	ExprResult ActOnCXXAssumeAttr(Stmt St, const* ParsedAttr &A,
11401	SourceRange Range);
11402	ExprResult BuildCXXAssumeExpr(Expr *Assumption,
11403	const IdentifierInfo *AttrName,
11404	SourceRange Range);
11405
11406	///@}
11407
11408	//
11409	//
11410	// -------------------------------------------------------------------------
11411	//
11412	//
11413
11414	/// \name C++ Templates
11415	/// Implementations are in SemaTemplate.cpp
11416	///@{
11417
11418	public:
11419	// Saves the current floating-point pragma stack and clear it in this Sema.
11420	class FpPragmaStackSaveRAII {
11421	public:
11422	FpPragmaStackSaveRAII(Sema &S)
11423	: S(S), SavedStack (std::move(S.FpPragmaStack)) {
11424	S.FpPragmaStack.Stack.clear();
11425	}
11426	~FpPragmaStackSaveRAII() { S.FpPragmaStack = std::move(SavedStack); }
11427	FpPragmaStackSaveRAII(const FpPragmaStackSaveRAII &) = delete;
11428	FpPragmaStackSaveRAII &operator=(const FpPragmaStackSaveRAII &) = delete;
11429
11430	private:
11431	Sema &S;
11432	PragmaStack<FPOptionsOverride> SavedStack;
11433	};
11434
11435	void resetFPOptions(FPOptions FPO) {
11436	CurFPFeatures = FPO;
11437	FpPragmaStack.CurrentValue = FPO.getChangesFrom(Base: FPOptions (LangOpts));
11438	}
11439
11440	ArrayRef<InventedTemplateParameterInfo> getInventedParameterInfos() const {
11441	return llvm::ArrayRef(InventedParameterInfos.begin() +
11442	InventedParameterInfosStart,
11443	InventedParameterInfos.end());
11444	}
11445
11446	ArrayRef<sema::FunctionScopeInfo > getFunctionScopes() const* {
11447	return llvm::ArrayRef(FunctionScopes.begin() + FunctionScopesStart,
11448	FunctionScopes.end());
11449	}
11450
11451	typedef llvm::MapVector<const FunctionDecl *,
11452	std::unique_ptr<LateParsedTemplate>>
11453	LateParsedTemplateMapT;
11454	LateParsedTemplateMapT LateParsedTemplateMap;
11455
11456	/// Determine the number of levels of enclosing template parameters. This is
11457	/// only usable while parsing. Note that this does not include dependent
11458	/// contexts in which no template parameters have yet been declared, such as
11459	/// in a terse function template or generic lambda before the first 'auto' is
11460	/// encountered.
11461	unsigned getTemplateDepth(Scope S) const*;
11462
11463	void FilterAcceptableTemplateNames(LookupResult &R,
11464	bool AllowFunctionTemplates = true,
11465	bool AllowDependent = true);
11466	bool hasAnyAcceptableTemplateNames(LookupResult &R,
11467	bool AllowFunctionTemplates = true,
11468	bool AllowDependent = true,
11469	bool AllowNonTemplateFunctions = false);
11470	/// Try to interpret the lookup result D as a template-name.
11471	///
11472	/// \param D A declaration found by name lookup.
11473	/// \param AllowFunctionTemplates Whether function templates should be
11474	/// considered valid results.
11475	/// \param AllowDependent Whether unresolved using declarations (that might
11476	/// name templates) should be considered valid results.
11477	static NamedDecl getAsTemplateNameDecl(NamedDecl D,
11478	bool AllowFunctionTemplates = true,
11479	bool AllowDependent = true);
11480
11481	enum TemplateNameIsRequiredTag { TemplateNameIsRequired };
11482	/// Whether and why a template name is required in this lookup.
11483	class RequiredTemplateKind {
11484	public:
11485	/// Template name is required if TemplateKWLoc is valid.
11486	RequiredTemplateKind(SourceLocation TemplateKWLoc = SourceLocation ())
11487	: TemplateKW (TemplateKWLoc) {}
11488	/// Template name is unconditionally required.
11489	RequiredTemplateKind(TemplateNameIsRequiredTag) {}
11490
11491	SourceLocation getTemplateKeywordLoc() const {
11492	return TemplateKW.value_or(u: SourceLocation ());
11493	}
11494	bool hasTemplateKeyword() const {
11495	return getTemplateKeywordLoc().isValid();
11496	}
11497	bool isRequired() const { return TemplateKW != SourceLocation (); }
11498	explicit operator bool() const { return isRequired(); }
11499
11500	private:
11501	std::optional<SourceLocation> TemplateKW;
11502	};
11503
11504	enum class AssumedTemplateKind {
11505	/// This is not assumed to be a template name.
11506	None,
11507	/// This is assumed to be a template name because lookup found nothing.
11508	FoundNothing,
11509	/// This is assumed to be a template name because lookup found one or more
11510	/// functions (but no function templates).
11511	FoundFunctions,
11512	};
11513
11514	bool
11515	LookupTemplateName(LookupResult &R, Scope *S, CXXScopeSpec &SS,
11516	QualType ObjectType, bool EnteringContext,
11517	RequiredTemplateKind RequiredTemplate = SourceLocation (),
11518	AssumedTemplateKind ATK = nullptr*,
11519	bool AllowTypoCorrection = true);
11520
11521	TemplateNameKind isTemplateName(Scope *S, CXXScopeSpec &SS,
11522	bool hasTemplateKeyword,
11523	const UnqualifiedId &Name,
11524	ParsedType ObjectType, bool EnteringContext,
11525	TemplateTy &Template,
11526	bool &MemberOfUnknownSpecialization,
11527	bool Disambiguation = false);
11528
11529	/// Try to resolve an undeclared template name as a type template.
11530	///
11531	/// Sets II to the identifier corresponding to the template name, and updates
11532	/// Name to a corresponding (typo-corrected) type template name and TNK to
11533	/// the corresponding kind, if possible.
11534	void ActOnUndeclaredTypeTemplateName(Scope *S, TemplateTy &Name,
11535	TemplateNameKind &TNK,
11536	SourceLocation NameLoc,
11537	IdentifierInfo *&II);
11538
11539	/// Determine whether a particular identifier might be the name in a C++1z
11540	/// deduction-guide declaration.
11541	bool isDeductionGuideName(Scope S, const* IdentifierInfo &Name,
11542	SourceLocation NameLoc, CXXScopeSpec &SS,
11543	ParsedTemplateTy Template = nullptr*);
11544
11545	bool DiagnoseUnknownTemplateName(const IdentifierInfo &II,
11546	SourceLocation IILoc, Scope *S,
11547	const CXXScopeSpec *SS,
11548	TemplateTy &SuggestedTemplate,
11549	TemplateNameKind &SuggestedKind);
11550
11551	/// Determine whether we would be unable to instantiate this template (because
11552	/// it either has no definition, or is in the process of being instantiated).
11553	bool DiagnoseUninstantiableTemplate(
11554	SourceLocation PointOfInstantiation, NamedDecl *Instantiation,
11555	bool InstantiatedFromMember, const NamedDecl *Pattern,
11556	const NamedDecl *PatternDef, TemplateSpecializationKind TSK,
11557	bool Complain = true, bool Unreachable = nullptr*);
11558
11559	/// DiagnoseTemplateParameterShadow - Produce a diagnostic complaining
11560	/// that the template parameter 'PrevDecl' is being shadowed by a new
11561	/// declaration at location Loc. Returns true to indicate that this is
11562	/// an error, and false otherwise.
11563	///
11564	/// \param Loc The location of the declaration that shadows a template
11565	/// parameter.
11566	///
11567	/// \param PrevDecl The template parameter that the declaration shadows.
11568	///
11569	/// \param SupportedForCompatibility Whether to issue the diagnostic as
11570	/// a warning for compatibility with older versions of clang.
11571	/// Ignored when MSVC compatibility is enabled.
11572	void DiagnoseTemplateParameterShadow(SourceLocation Loc, Decl *PrevDecl,
11573	bool SupportedForCompatibility = false);
11574
11575	/// AdjustDeclIfTemplate - If the given decl happens to be a template, reset
11576	/// the parameter D to reference the templated declaration and return a
11577	/// pointer to the template declaration. Otherwise, do nothing to D and return
11578	/// null.
11579	TemplateDecl AdjustDeclIfTemplate(Decl &Decl);
11580
11581	/// ActOnTypeParameter - Called when a C++ template type parameter
11582	/// (e.g., "typename T") has been parsed. Typename specifies whether
11583	/// the keyword "typename" was used to declare the type parameter
11584	/// (otherwise, "class" was used), and KeyLoc is the location of the
11585	/// "class" or "typename" keyword. ParamName is the name of the
11586	/// parameter (NULL indicates an unnamed template parameter) and
11587	/// ParamNameLoc is the location of the parameter name (if any).
11588	/// If the type parameter has a default argument, it will be added
11589	/// later via ActOnTypeParameterDefault.
11590	NamedDecl ActOnTypeParameter(Scope S, bool Typename,
11591	SourceLocation EllipsisLoc,
11592	SourceLocation KeyLoc,
11593	IdentifierInfo *ParamName,
11594	SourceLocation ParamNameLoc, unsigned Depth,
11595	unsigned Position, SourceLocation EqualLoc,
11596	ParsedType DefaultArg, bool HasTypeConstraint);
11597
11598	bool CheckTypeConstraint(TemplateIdAnnotation *TypeConstraint);
11599
11600	bool ActOnTypeConstraint(const CXXScopeSpec &SS,
11601	TemplateIdAnnotation *TypeConstraint,
11602	TemplateTypeParmDecl *ConstrainedParameter,
11603	SourceLocation EllipsisLoc);
11604	bool BuildTypeConstraint(const CXXScopeSpec &SS,
11605	TemplateIdAnnotation *TypeConstraint,
11606	TemplateTypeParmDecl *ConstrainedParameter,
11607	SourceLocation EllipsisLoc,
11608	bool AllowUnexpandedPack);
11609
11610	/// Attach a type-constraint to a template parameter.
11611	/// \returns true if an error occurred. This can happen if the
11612	/// immediately-declared constraint could not be formed (e.g. incorrect number
11613	/// of arguments for the named concept).
11614	bool AttachTypeConstraint(NestedNameSpecifierLoc NS,
11615	DeclarationNameInfo NameInfo,
11616	TemplateDecl NamedConcept, NamedDecl FoundDecl,
11617	const TemplateArgumentListInfo *TemplateArgs,
11618	TemplateTypeParmDecl *ConstrainedParameter,
11619	SourceLocation EllipsisLoc);
11620
11621	bool AttachTypeConstraint(AutoTypeLoc TL,
11622	NonTypeTemplateParmDecl *NewConstrainedParm,
11623	NonTypeTemplateParmDecl *OrigConstrainedParm,
11624	SourceLocation EllipsisLoc);
11625
11626	/// Require the given type to be a structural type, and diagnose if it is not.
11627	///
11628	/// \return \c true if an error was produced.
11629	bool RequireStructuralType(QualType T, SourceLocation Loc);
11630
11631	/// Check that the type of a non-type template parameter is
11632	/// well-formed.
11633	///
11634	/// \returns the (possibly-promoted) parameter type if valid;
11635	/// otherwise, produces a diagnostic and returns a NULL type.
11636	QualType CheckNonTypeTemplateParameterType(TypeSourceInfo *&TSI,
11637	SourceLocation Loc);
11638	QualType CheckNonTypeTemplateParameterType(QualType T, SourceLocation Loc);
11639
11640	NamedDecl ActOnNonTypeTemplateParameter(Scope S, Declarator &D,
11641	unsigned Depth, unsigned Position,
11642	SourceLocation EqualLoc,
11643	Expr *DefaultArg);
11644
11645	/// ActOnTemplateTemplateParameter - Called when a C++ template template
11646	/// parameter (e.g. T in template <template \<typename> class T> class array)
11647	/// has been parsed. S is the current scope.
11648	NamedDecl *ActOnTemplateTemplateParameter(
11649	Scope *S, SourceLocation TmpLoc, TemplateNameKind Kind,
11650	bool TypenameKeyword, TemplateParameterList *Params,
11651	SourceLocation EllipsisLoc, IdentifierInfo *ParamName,
11652	SourceLocation ParamNameLoc, unsigned Depth, unsigned Position,
11653	SourceLocation EqualLoc, ParsedTemplateArgument DefaultArg);
11654
11655	/// ActOnTemplateParameterList - Builds a TemplateParameterList, optionally
11656	/// constrained by RequiresClause, that contains the template parameters in
11657	/// Params.
11658	TemplateParameterList *ActOnTemplateParameterList(
11659	unsigned Depth, SourceLocation ExportLoc, SourceLocation TemplateLoc,
11660	SourceLocation LAngleLoc, ArrayRef<NamedDecl *> Params,
11661	SourceLocation RAngleLoc, Expr *RequiresClause);
11662
11663	/// The context in which we are checking a template parameter list.
11664	enum TemplateParamListContext {
11665	// For this context, Class, Variable, TypeAlias, and non-pack Template
11666	// Template Parameters are treated uniformly.
11667	TPC_Other,
11668
11669	TPC_FunctionTemplate,
11670	TPC_ClassTemplateMember,
11671	TPC_FriendClassTemplate,
11672	TPC_FriendFunctionTemplate,
11673	TPC_FriendFunctionTemplateDefinition,
11674	TPC_TemplateTemplateParameterPack,
11675	};
11676
11677	/// Checks the validity of a template parameter list, possibly
11678	/// considering the template parameter list from a previous
11679	/// declaration.
11680	///
11681	/// If an "old" template parameter list is provided, it must be
11682	/// equivalent (per TemplateParameterListsAreEqual) to the "new"
11683	/// template parameter list.
11684	///
11685	/// \param NewParams Template parameter list for a new template
11686	/// declaration. This template parameter list will be updated with any
11687	/// default arguments that are carried through from the previous
11688	/// template parameter list.
11689	///
11690	/// \param OldParams If provided, template parameter list from a
11691	/// previous declaration of the same template. Default template
11692	/// arguments will be merged from the old template parameter list to
11693	/// the new template parameter list.
11694	///
11695	/// \param TPC Describes the context in which we are checking the given
11696	/// template parameter list.
11697	///
11698	/// \param SkipBody If we might have already made a prior merged definition
11699	/// of this template visible, the corresponding body-skipping information.
11700	/// Default argument redefinition is not an error when skipping such a body,
11701	/// because (under the ODR) we can assume the default arguments are the same
11702	/// as the prior merged definition.
11703	///
11704	/// \returns true if an error occurred, false otherwise.
11705	bool CheckTemplateParameterList(TemplateParameterList *NewParams,
11706	TemplateParameterList *OldParams,
11707	TemplateParamListContext TPC,
11708	SkipBodyInfo SkipBody = nullptr*);
11709
11710	/// Match the given template parameter lists to the given scope
11711	/// specifier, returning the template parameter list that applies to the
11712	/// name.
11713	///
11714	/// \param DeclStartLoc the start of the declaration that has a scope
11715	/// specifier or a template parameter list.
11716	///
11717	/// \param DeclLoc The location of the declaration itself.
11718	///
11719	/// \param SS the scope specifier that will be matched to the given template
11720	/// parameter lists. This scope specifier precedes a qualified name that is
11721	/// being declared.
11722	///
11723	/// \param TemplateId The template-id following the scope specifier, if there
11724	/// is one. Used to check for a missing 'template<>'.
11725	///
11726	/// \param ParamLists the template parameter lists, from the outermost to the
11727	/// innermost template parameter lists.
11728	///
11729	/// \param IsFriend Whether to apply the slightly different rules for
11730	/// matching template parameters to scope specifiers in friend
11731	/// declarations.
11732	///
11733	/// \param IsMemberSpecialization will be set true if the scope specifier
11734	/// denotes a fully-specialized type, and therefore this is a declaration of
11735	/// a member specialization.
11736	///
11737	/// \returns the template parameter list, if any, that corresponds to the
11738	/// name that is preceded by the scope specifier @p SS. This template
11739	/// parameter list may have template parameters (if we're declaring a
11740	/// template) or may have no template parameters (if we're declaring a
11741	/// template specialization), or may be NULL (if what we're declaring isn't
11742	/// itself a template).
11743	TemplateParameterList *MatchTemplateParametersToScopeSpecifier(
11744	SourceLocation DeclStartLoc, SourceLocation DeclLoc,
11745	const CXXScopeSpec &SS, TemplateIdAnnotation *TemplateId,
11746	ArrayRef<TemplateParameterList > ParamLists, bool* IsFriend,
11747	bool &IsMemberSpecialization, bool &Invalid,
11748	bool SuppressDiagnostic = false);
11749
11750	/// Returns the template parameter list with all default template argument
11751	/// information.
11752	TemplateParameterList GetTemplateParameterList(TemplateDecl TD);
11753
11754	DeclResult CheckClassTemplate(
11755	Scope S, unsigned* TagSpec, TagUseKind TUK, SourceLocation KWLoc,
11756	CXXScopeSpec &SS, IdentifierInfo *Name, SourceLocation NameLoc,
11757	const ParsedAttributesView &Attr, TemplateParameterList *TemplateParams,
11758	AccessSpecifier AS, SourceLocation ModulePrivateLoc,
11759	SourceLocation FriendLoc, unsigned NumOuterTemplateParamLists,
11760	TemplateParameterList **OuterTemplateParamLists,
11761	SkipBodyInfo SkipBody = nullptr*);
11762
11763	/// Translates template arguments as provided by the parser
11764	/// into template arguments used by semantic analysis.
11765	void translateTemplateArguments(const ASTTemplateArgsPtr &In,
11766	TemplateArgumentListInfo &Out);
11767
11768	/// Convert a parsed type into a parsed template argument. This is mostly
11769	/// trivial, except that we may have parsed a C++17 deduced class template
11770	/// specialization type, in which case we should form a template template
11771	/// argument instead of a type template argument.
11772	ParsedTemplateArgument ActOnTemplateTypeArgument(TypeResult ParsedType);
11773
11774	void NoteAllFoundTemplates(TemplateName Name);
11775
11776	QualType CheckTemplateIdType(ElaboratedTypeKeyword Keyword,
11777	TemplateName Template,
11778	SourceLocation TemplateLoc,
11779	TemplateArgumentListInfo &TemplateArgs,
11780	Scope Scope, bool* ForNestedNameSpecifier);
11781
11782	TypeResult
11783	ActOnTemplateIdType(Scope *S, ElaboratedTypeKeyword ElaboratedKeyword,
11784	SourceLocation ElaboratedKeywordLoc, CXXScopeSpec &SS,
11785	SourceLocation TemplateKWLoc, TemplateTy Template,
11786	const IdentifierInfo *TemplateII,
11787	SourceLocation TemplateIILoc, SourceLocation LAngleLoc,
11788	ASTTemplateArgsPtr TemplateArgs, SourceLocation RAngleLoc,
11789	bool IsCtorOrDtorName = false, bool IsClassName = false,
11790	ImplicitTypenameContext AllowImplicitTypename =
11791	ImplicitTypenameContext::No);
11792
11793	/// Parsed an elaborated-type-specifier that refers to a template-id,
11794	/// such as \c class T::template apply<U>.
11795	TypeResult ActOnTagTemplateIdType(
11796	TagUseKind TUK, TypeSpecifierType TagSpec, SourceLocation TagLoc,
11797	CXXScopeSpec &SS, SourceLocation TemplateKWLoc, TemplateTy TemplateD,
11798	SourceLocation TemplateLoc, SourceLocation LAngleLoc,
11799	ASTTemplateArgsPtr TemplateArgsIn, SourceLocation RAngleLoc);
11800
11801	DeclResult ActOnVarTemplateSpecialization(
11802	Scope S, Declarator &D, TypeSourceInfo TSI, LookupResult &Previous,
11803	SourceLocation TemplateKWLoc, TemplateParameterList *TemplateParams,
11804	StorageClass SC, bool IsPartialSpecialization);
11805
11806	/// Get the specialization of the given variable template corresponding to
11807	/// the specified argument list, or a null-but-valid result if the arguments
11808	/// are dependent.
11809	DeclResult CheckVarTemplateId(VarTemplateDecl *Template,
11810	SourceLocation TemplateLoc,
11811	SourceLocation TemplateNameLoc,
11812	const TemplateArgumentListInfo &TemplateArgs,
11813	bool SetWrittenArgs);
11814
11815	/// Form a reference to the specialization of the given variable template
11816	/// corresponding to the specified argument list, or a null-but-valid result
11817	/// if the arguments are dependent.
11818	ExprResult CheckVarTemplateId(const CXXScopeSpec &SS,
11819	const DeclarationNameInfo &NameInfo,
11820	VarTemplateDecl Template, NamedDecl FoundD,
11821	SourceLocation TemplateLoc,
11822	const TemplateArgumentListInfo *TemplateArgs);
11823
11824	ExprResult CheckVarOrConceptTemplateTemplateId(
11825	const CXXScopeSpec &SS, const DeclarationNameInfo &NameInfo,
11826	TemplateTemplateParmDecl *Template, SourceLocation TemplateLoc,
11827	const TemplateArgumentListInfo *TemplateArgs);
11828
11829	ExprResult
11830	CheckConceptTemplateId(const CXXScopeSpec &SS, SourceLocation TemplateKWLoc,
11831	const DeclarationNameInfo &ConceptNameInfo,
11832	NamedDecl FoundDecl, TemplateDecl NamedConcept,
11833	const TemplateArgumentListInfo *TemplateArgs,
11834	bool DoCheckConstraintSatisfaction = true);
11835
11836	void diagnoseMissingTemplateArguments(TemplateName Name, SourceLocation Loc);
11837	void diagnoseMissingTemplateArguments(const CXXScopeSpec &SS,
11838	bool TemplateKeyword, TemplateDecl *TD,
11839	SourceLocation Loc);
11840
11841	ExprResult BuildTemplateIdExpr(const CXXScopeSpec &SS,
11842	SourceLocation TemplateKWLoc, LookupResult &R,
11843	bool RequiresADL,
11844	const TemplateArgumentListInfo *TemplateArgs);
11845
11846	// We actually only call this from template instantiation.
11847	ExprResult
11848	BuildQualifiedTemplateIdExpr(CXXScopeSpec &SS, SourceLocation TemplateKWLoc,
11849	const DeclarationNameInfo &NameInfo,
11850	const TemplateArgumentListInfo *TemplateArgs,
11851	bool IsAddressOfOperand);
11852
11853	UnsignedOrNone getPackIndex(TemplateArgument Pack) const {
11854	return Pack.pack_size() - `1` - *ArgPackSubstIndex;
11855	}
11856
11857	TemplateArgument
11858	getPackSubstitutedTemplateArgument(TemplateArgument Arg) const {
11859	Arg = Arg.pack_elements()[*ArgPackSubstIndex];
11860	if (Arg.isPackExpansion())
11861	Arg = Arg.getPackExpansionPattern();
11862	return Arg;
11863	}
11864
11865	ExprResult BuildSubstNonTypeTemplateParmExpr(
11866	Decl AssociatedDecl, const* NonTypeTemplateParmDecl *NTTP,
11867	SourceLocation loc, TemplateArgument Replacement,
11868	UnsignedOrNone PackIndex, bool Final);
11869
11870	/// Form a template name from a name that is syntactically required to name a
11871	/// template, either due to use of the 'template' keyword or because a name in
11872	/// this syntactic context is assumed to name a template (C++
11873	/// [temp.names]p2-4).
11874	///
11875	/// This action forms a template name given the name of the template and its
11876	/// optional scope specifier. This is used when the 'template' keyword is used
11877	/// or when the parsing context unambiguously treats a following '<' as
11878	/// introducing a template argument list. Note that this may produce a
11879	/// non-dependent template name if we can perform the lookup now and identify
11880	/// the named template.
11881	///
11882	/// For example, given "x.MetaFun::template apply", the scope specifier
11883	/// \p SS will be "MetaFun::", \p TemplateKWLoc contains the location
11884	/// of the "template" keyword, and "apply" is the \p Name.
11885	TemplateNameKind ActOnTemplateName(Scope *S, CXXScopeSpec &SS,
11886	SourceLocation TemplateKWLoc,
11887	const UnqualifiedId &Name,
11888	ParsedType ObjectType,
11889	bool EnteringContext, TemplateTy &Template,
11890	bool AllowInjectedClassName = false);
11891
11892	DeclResult ActOnClassTemplateSpecialization(
11893	Scope S, unsigned* TagSpec, TagUseKind TUK, SourceLocation KWLoc,
11894	SourceLocation ModulePrivateLoc, CXXScopeSpec &SS,
11895	TemplateIdAnnotation &TemplateId, const ParsedAttributesView &Attr,
11896	MultiTemplateParamsArg TemplateParameterLists,
11897	SkipBodyInfo SkipBody = nullptr*);
11898
11899	/// Check the non-type template arguments of a class template
11900	/// partial specialization according to C++ [temp.class.spec]p9.
11901	///
11902	/// \param TemplateNameLoc the location of the template name.
11903	/// \param PrimaryTemplate the template parameters of the primary class
11904	/// template.
11905	/// \param NumExplicit the number of explicitly-specified template arguments.
11906	/// \param TemplateArgs the template arguments of the class template
11907	/// partial specialization.
11908	///
11909	/// \returns \c true if there was an error, \c false otherwise.
11910	bool CheckTemplatePartialSpecializationArgs(SourceLocation Loc,
11911	TemplateDecl *PrimaryTemplate,
11912	unsigned NumExplicitArgs,
11913	ArrayRef<TemplateArgument> Args);
11914	void CheckTemplatePartialSpecialization(
11915	ClassTemplatePartialSpecializationDecl *Partial);
11916	void CheckTemplatePartialSpecialization(
11917	VarTemplatePartialSpecializationDecl *Partial);
11918
11919	Decl ActOnTemplateDeclarator(Scope S,
11920	MultiTemplateParamsArg TemplateParameterLists,
11921	Declarator &D);
11922
11923	/// Diagnose cases where we have an explicit template specialization
11924	/// before/after an explicit template instantiation, producing diagnostics
11925	/// for those cases where they are required and determining whether the
11926	/// new specialization/instantiation will have any effect.
11927	///
11928	/// \param NewLoc the location of the new explicit specialization or
11929	/// instantiation.
11930	///
11931	/// \param NewTSK the kind of the new explicit specialization or
11932	/// instantiation.
11933	///
11934	/// \param PrevDecl the previous declaration of the entity.
11935	///
11936	/// \param PrevTSK the kind of the old explicit specialization or
11937	/// instantiatin.
11938	///
11939	/// \param PrevPointOfInstantiation if valid, indicates where the previous
11940	/// declaration was instantiated (either implicitly or explicitly).
11941	///
11942	/// \param HasNoEffect will be set to true to indicate that the new
11943	/// specialization or instantiation has no effect and should be ignored.
11944	///
11945	/// \returns true if there was an error that should prevent the introduction
11946	/// of the new declaration into the AST, false otherwise.
11947	bool CheckSpecializationInstantiationRedecl(
11948	SourceLocation NewLoc,
11949	TemplateSpecializationKind ActOnExplicitInstantiationNewTSK,
11950	NamedDecl *PrevDecl, TemplateSpecializationKind PrevTSK,
11951	SourceLocation PrevPtOfInstantiation, bool &SuppressNew);
11952
11953	/// Perform semantic analysis for the given dependent function
11954	/// template specialization.
11955	///
11956	/// The only possible way to get a dependent function template specialization
11957	/// is with a friend declaration, like so:
11958	///
11959	/// \code
11960	/// template \<class T> void foo(T);
11961	/// template \<class T> class A {
11962	/// friend void foo<>(T);
11963	/// };
11964	/// \endcode
11965	///
11966	/// There really isn't any useful analysis we can do here, so we
11967	/// just store the information.
11968	bool CheckDependentFunctionTemplateSpecialization(
11969	FunctionDecl FD, const* TemplateArgumentListInfo *ExplicitTemplateArgs,
11970	LookupResult &Previous);
11971
11972	/// Perform semantic analysis for the given function template
11973	/// specialization.
11974	///
11975	/// This routine performs all of the semantic analysis required for an
11976	/// explicit function template specialization. On successful completion,
11977	/// the function declaration \p FD will become a function template
11978	/// specialization.
11979	///
11980	/// \param FD the function declaration, which will be updated to become a
11981	/// function template specialization.
11982	///
11983	/// \param ExplicitTemplateArgs the explicitly-provided template arguments,
11984	/// if any. Note that this may be valid info even when 0 arguments are
11985	/// explicitly provided as in, e.g., \c void sort<>(char, char);
11986	/// as it anyway contains info on the angle brackets locations.
11987	///
11988	/// \param Previous the set of declarations that may be specialized by
11989	/// this function specialization.
11990	///
11991	/// \param QualifiedFriend whether this is a lookup for a qualified friend
11992	/// declaration with no explicit template argument list that might be
11993	/// befriending a function template specialization.
11994	bool CheckFunctionTemplateSpecialization(
11995	FunctionDecl FD, TemplateArgumentListInfo ExplicitTemplateArgs,
11996	LookupResult &Previous, bool QualifiedFriend = false);
11997
11998	/// Perform semantic analysis for the given non-template member
11999	/// specialization.
12000	///
12001	/// This routine performs all of the semantic analysis required for an
12002	/// explicit member function specialization. On successful completion,
12003	/// the function declaration \p FD will become a member function
12004	/// specialization.
12005	///
12006	/// \param Member the member declaration, which will be updated to become a
12007	/// specialization.
12008	///
12009	/// \param Previous the set of declarations, one of which may be specialized
12010	/// by this function specialization; the set will be modified to contain the
12011	/// redeclared member.
12012	bool CheckMemberSpecialization(NamedDecl *Member, LookupResult &Previous);
12013	void CompleteMemberSpecialization(NamedDecl *Member, LookupResult &Previous);
12014
12015	// Explicit instantiation of a class template specialization
12016	DeclResult ActOnExplicitInstantiation(
12017	Scope *S, SourceLocation ExternLoc, SourceLocation TemplateLoc,
12018	unsigned TagSpec, SourceLocation KWLoc, const CXXScopeSpec &SS,
12019	TemplateTy Template, SourceLocation TemplateNameLoc,
12020	SourceLocation LAngleLoc, ASTTemplateArgsPtr TemplateArgs,
12021	SourceLocation RAngleLoc, const ParsedAttributesView &Attr);
12022
12023	// Explicit instantiation of a member class of a class template.
12024	DeclResult ActOnExplicitInstantiation(Scope *S, SourceLocation ExternLoc,
12025	SourceLocation TemplateLoc,
12026	unsigned TagSpec, SourceLocation KWLoc,
12027	CXXScopeSpec &SS, IdentifierInfo *Name,
12028	SourceLocation NameLoc,
12029	const ParsedAttributesView &Attr);
12030
12031	DeclResult ActOnExplicitInstantiation(Scope *S, SourceLocation ExternLoc,
12032	SourceLocation TemplateLoc,
12033	Declarator &D);
12034
12035	/// If the given template parameter has a default template
12036	/// argument, substitute into that default template argument and
12037	/// return the corresponding template argument.
12038	TemplateArgumentLoc SubstDefaultTemplateArgumentIfAvailable(
12039	TemplateDecl *Template, SourceLocation TemplateKWLoc,
12040	SourceLocation TemplateNameLoc, SourceLocation RAngleLoc, Decl *Param,
12041	ArrayRef<TemplateArgument> SugaredConverted,
12042	ArrayRef<TemplateArgument> CanonicalConverted, bool &HasDefaultArg);
12043
12044	/// Returns the top most location responsible for the definition of \p N.
12045	/// If \p N is a a template specialization, this is the location
12046	/// of the top of the instantiation stack.
12047	/// Otherwise, the location of \p N is returned.
12048	SourceLocation getTopMostPointOfInstantiation(const NamedDecl ) const*;
12049
12050	/// Specifies the context in which a particular template
12051	/// argument is being checked.
12052	enum CheckTemplateArgumentKind {
12053	/// The template argument was specified in the code or was
12054	/// instantiated with some deduced template arguments.
12055	CTAK_Specified,
12056
12057	/// The template argument was deduced via template argument
12058	/// deduction.
12059	CTAK_Deduced,
12060
12061	/// The template argument was deduced from an array bound
12062	/// via template argument deduction.
12063	CTAK_DeducedFromArrayBound
12064	};
12065
12066	struct CheckTemplateArgumentInfo {
12067	explicit CheckTemplateArgumentInfo(bool PartialOrdering = false,
12068	bool MatchingTTP = false)
12069	: PartialOrdering(PartialOrdering), MatchingTTP(MatchingTTP) {}
12070	CheckTemplateArgumentInfo(const CheckTemplateArgumentInfo &) = delete;
12071	CheckTemplateArgumentInfo &
12072	operator=(const CheckTemplateArgumentInfo &) = delete;
12073
12074	/// The checked, converted argument will be added to the
12075	/// end of these vectors.
12076	SmallVector<TemplateArgument, `4`> SugaredConverted, CanonicalConverted;
12077
12078	/// The check is being performed in the context of partial ordering.
12079	bool PartialOrdering;
12080
12081	/// If true, assume these template arguments are
12082	/// the injected template arguments for a template template parameter.
12083	/// This will relax the requirement that all its possible uses are valid:
12084	/// TTP checking is loose, and assumes that invalid uses will be diagnosed
12085	/// during instantiation.
12086	bool MatchingTTP;
12087
12088	/// Is set to true when, in the context of TTP matching, a pack parameter
12089	/// matches non-pack arguments.
12090	bool StrictPackMatch = false;
12091	};
12092
12093	/// Check that the given template argument corresponds to the given
12094	/// template parameter.
12095	///
12096	/// \param Param The template parameter against which the argument will be
12097	/// checked.
12098	///
12099	/// \param Arg The template argument, which may be updated due to conversions.
12100	///
12101	/// \param Template The template in which the template argument resides.
12102	///
12103	/// \param TemplateLoc The location of the template name for the template
12104	/// whose argument list we're matching.
12105	///
12106	/// \param RAngleLoc The location of the right angle bracket ('>') that closes
12107	/// the template argument list.
12108	///
12109	/// \param ArgumentPackIndex The index into the argument pack where this
12110	/// argument will be placed. Only valid if the parameter is a parameter pack.
12111	///
12112	/// \param CTAK Describes how we arrived at this particular template argument:
12113	/// explicitly written, deduced, etc.
12114	///
12115	/// \returns true on error, false otherwise.
12116	bool CheckTemplateArgument(NamedDecl *Param, TemplateArgumentLoc &Arg,
12117	NamedDecl *Template, SourceLocation TemplateLoc,
12118	SourceLocation RAngleLoc,
12119	unsigned ArgumentPackIndex,
12120	CheckTemplateArgumentInfo &CTAI,
12121	CheckTemplateArgumentKind CTAK);
12122
12123	/// Check that the given template arguments can be provided to
12124	/// the given template, converting the arguments along the way.
12125	///
12126	/// \param Template The template to which the template arguments are being
12127	/// provided.
12128	///
12129	/// \param TemplateLoc The location of the template name in the source.
12130	///
12131	/// \param TemplateArgs The list of template arguments. If the template is
12132	/// a template template parameter, this function may extend the set of
12133	/// template arguments to also include substituted, defaulted template
12134	/// arguments.
12135	///
12136	/// \param PartialTemplateArgs True if the list of template arguments is
12137	/// intentionally partial, e.g., because we're checking just the initial
12138	/// set of template arguments.
12139	///
12140	/// \param Converted Will receive the converted, canonicalized template
12141	/// arguments.
12142	///
12143	/// \param UpdateArgsWithConversions If \c true, update \p TemplateArgs to
12144	/// contain the converted forms of the template arguments as written.
12145	/// Otherwise, \p TemplateArgs will not be modified.
12146	///
12147	/// \param ConstraintsNotSatisfied If provided, and an error occurred, will
12148	/// receive true if the cause for the error is the associated constraints of
12149	/// the template not being satisfied by the template arguments.
12150	///
12151	/// \param DefaultArgs any default arguments from template specialization
12152	/// deduction.
12153	///
12154	/// \returns true if an error occurred, false otherwise.
12155	bool CheckTemplateArgumentList(TemplateDecl *Template,
12156	SourceLocation TemplateLoc,
12157	TemplateArgumentListInfo &TemplateArgs,
12158	const DefaultArguments &DefaultArgs,
12159	bool PartialTemplateArgs,
12160	CheckTemplateArgumentInfo &CTAI,
12161	bool UpdateArgsWithConversions = true,
12162	bool ConstraintsNotSatisfied = nullptr*);
12163
12164	bool CheckTemplateArgumentList(
12165	TemplateDecl Template, TemplateParameterList Params,
12166	SourceLocation TemplateLoc, TemplateArgumentListInfo &TemplateArgs,
12167	const DefaultArguments &DefaultArgs, bool PartialTemplateArgs,
12168	CheckTemplateArgumentInfo &CTAI, bool UpdateArgsWithConversions = true,
12169	bool ConstraintsNotSatisfied = nullptr*);
12170
12171	bool CheckTemplateTypeArgument(
12172	TemplateTypeParmDecl *Param, TemplateArgumentLoc &Arg,
12173	SmallVectorImpl<TemplateArgument> &SugaredConverted,
12174	SmallVectorImpl<TemplateArgument> &CanonicalConverted);
12175
12176	/// Check a template argument against its corresponding
12177	/// template type parameter.
12178	///
12179	/// This routine implements the semantics of C++ [temp.arg.type]. It
12180	/// returns true if an error occurred, and false otherwise.
12181	bool CheckTemplateArgument(TypeSourceInfo *Arg);
12182
12183	/// Check a template argument against its corresponding
12184	/// non-type template parameter.
12185	///
12186	/// This routine implements the semantics of C++ [temp.arg.nontype].
12187	/// If an error occurred, it returns ExprError(); otherwise, it
12188	/// returns the converted template argument. \p ParamType is the
12189	/// type of the non-type template parameter after it has been instantiated.
12190	ExprResult CheckTemplateArgument(NamedDecl *Param,
12191	QualType InstantiatedParamType, Expr *Arg,
12192	TemplateArgument &SugaredConverted,
12193	TemplateArgument &CanonicalConverted,
12194	bool StrictCheck,
12195	CheckTemplateArgumentKind CTAK);
12196
12197	/// Check a template argument against its corresponding
12198	/// template template parameter.
12199	///
12200	/// This routine implements the semantics of C++ [temp.arg.template].
12201	/// It returns true if an error occurred, and false otherwise.
12202	bool CheckTemplateTemplateArgument(TemplateTemplateParmDecl *Param,
12203	TemplateParameterList *Params,
12204	TemplateArgumentLoc &Arg,
12205	bool PartialOrdering,
12206	bool *StrictPackMatch);
12207
12208	bool CheckDeclCompatibleWithTemplateTemplate(TemplateDecl *Template,
12209	TemplateTemplateParmDecl *Param,
12210	const TemplateArgumentLoc &Arg);
12211
12212	void NoteTemplateLocation(const NamedDecl &Decl,
12213	std::optional<SourceRange> ParamRange = {});
12214	void NoteTemplateParameterLocation(const NamedDecl &Decl);
12215
12216	/// Given a non-type template argument that refers to a
12217	/// declaration and the type of its corresponding non-type template
12218	/// parameter, produce an expression that properly refers to that
12219	/// declaration.
12220	/// FIXME: This is used in some contexts where the resulting expression
12221	/// doesn't need to live too long. It would be useful if this function
12222	/// could return a temporary expression.
12223	ExprResult BuildExpressionFromDeclTemplateArgument(
12224	const TemplateArgument &Arg, QualType ParamType, SourceLocation Loc,
12225	NamedDecl TemplateParam = nullptr*);
12226	ExprResult
12227	BuildExpressionFromNonTypeTemplateArgument(const TemplateArgument &Arg,
12228	SourceLocation Loc);
12229
12230	/// Enumeration describing how template parameter lists are compared
12231	/// for equality.
12232	enum TemplateParameterListEqualKind {
12233	/// We are matching the template parameter lists of two templates
12234	/// that might be redeclarations.
12235	///
12236	/// \code
12237	/// template<typename T> struct X;
12238	/// template<typename T> struct X;
12239	/// \endcode
12240	TPL_TemplateMatch,
12241
12242	/// We are matching the template parameter lists of two template
12243	/// template parameters as part of matching the template parameter lists
12244	/// of two templates that might be redeclarations.
12245	///
12246	/// \code
12247	/// template<template<int I> class TT> struct X;
12248	/// template<template<int Value> class Other> struct X;
12249	/// \endcode
12250	TPL_TemplateTemplateParmMatch,
12251
12252	/// We are determining whether the template-parameters are equivalent
12253	/// according to C++ [temp.over.link]/6. This comparison does not consider
12254	/// constraints.
12255	///
12256	/// \code
12257	/// template<C1 T> void f(T);
12258	/// template<C2 T> void f(T);
12259	/// \endcode
12260	TPL_TemplateParamsEquivalent,
12261	};
12262
12263	// A struct to represent the 'new' declaration, which is either itself just
12264	// the named decl, or the important information we need about it in order to
12265	// do constraint comparisons.
12266	class TemplateCompareNewDeclInfo {
12267	const NamedDecl ND = nullptr*;
12268	const DeclContext DC = nullptr*;
12269	const DeclContext LexicalDC = nullptr*;
12270	SourceLocation Loc;
12271
12272	public:
12273	TemplateCompareNewDeclInfo(const NamedDecl *ND) : ND(ND) {}
12274	TemplateCompareNewDeclInfo(const DeclContext *DeclCtx,
12275	const DeclContext *LexicalDeclCtx,
12276	SourceLocation Loc)
12277
12278	: DC(DeclCtx), LexicalDC(LexicalDeclCtx), Loc (Loc) {
12279	assert(DC && LexicalDC &&
12280	"Constructor only for cases where we have the information to put "
12281	"in here");
12282	}
12283
12284	// If this was constructed with no information, we cannot do substitution
12285	// for constraint comparison, so make sure we can check that.
12286	bool isInvalid() const { return !ND && !DC; }
12287
12288	const NamedDecl getDecl() const* { return ND; }
12289
12290	bool ContainsDecl(const NamedDecl ND) const* { return this->ND == ND; }
12291
12292	const DeclContext getLexicalDeclContext() const* {
12293	return ND ? ND->getLexicalDeclContext() : LexicalDC;
12294	}
12295
12296	const DeclContext getDeclContext() const* {
12297	return ND ? ND->getDeclContext() : DC;
12298	}
12299
12300	SourceLocation getLocation() const { return ND ? ND->getLocation() : Loc; }
12301	};
12302
12303	/// Determine whether the given template parameter lists are
12304	/// equivalent.
12305	///
12306	/// \param New The new template parameter list, typically written in the
12307	/// source code as part of a new template declaration.
12308	///
12309	/// \param Old The old template parameter list, typically found via
12310	/// name lookup of the template declared with this template parameter
12311	/// list.
12312	///
12313	/// \param Complain If true, this routine will produce a diagnostic if
12314	/// the template parameter lists are not equivalent.
12315	///
12316	/// \param Kind describes how we are to match the template parameter lists.
12317	///
12318	/// \param TemplateArgLoc If this source location is valid, then we
12319	/// are actually checking the template parameter list of a template
12320	/// argument (New) against the template parameter list of its
12321	/// corresponding template template parameter (Old). We produce
12322	/// slightly different diagnostics in this scenario.
12323	///
12324	/// \returns True if the template parameter lists are equal, false
12325	/// otherwise.
12326	bool TemplateParameterListsAreEqual(
12327	const TemplateCompareNewDeclInfo &NewInstFrom, TemplateParameterList *New,
12328	const NamedDecl OldInstFrom, TemplateParameterList Old, bool Complain,
12329	TemplateParameterListEqualKind Kind,
12330	SourceLocation TemplateArgLoc = SourceLocation ());
12331
12332	bool TemplateParameterListsAreEqual(
12333	TemplateParameterList New, TemplateParameterList Old, bool Complain,
12334	TemplateParameterListEqualKind Kind,
12335	SourceLocation TemplateArgLoc = SourceLocation ()) {
12336	return TemplateParameterListsAreEqual(NewInstFrom: nullptr, New, OldInstFrom: nullptr, Old, Complain,
12337	Kind, TemplateArgLoc);
12338	}
12339
12340	/// Check whether a template can be declared within this scope.
12341	///
12342	/// If the template declaration is valid in this scope, returns
12343	/// false. Otherwise, issues a diagnostic and returns true.
12344	bool CheckTemplateDeclScope(Scope S, TemplateParameterList TemplateParams);
12345
12346	/// Called when the parser has parsed a C++ typename
12347	/// specifier, e.g., "typename T::type".
12348	///
12349	/// \param S The scope in which this typename type occurs.
12350	/// \param TypenameLoc the location of the 'typename' keyword
12351	/// \param SS the nested-name-specifier following the typename (e.g., 'T::').
12352	/// \param II the identifier we're retrieving (e.g., 'type' in the example).
12353	/// \param IdLoc the location of the identifier.
12354	/// \param IsImplicitTypename context where T::type refers to a type.
12355	TypeResult ActOnTypenameType(
12356	Scope S, SourceLocation TypenameLoc, const* CXXScopeSpec &SS,
12357	const IdentifierInfo &II, SourceLocation IdLoc,
12358	ImplicitTypenameContext IsImplicitTypename = ImplicitTypenameContext::No);
12359
12360	/// Called when the parser has parsed a C++ typename
12361	/// specifier that ends in a template-id, e.g.,
12362	/// "typename MetaFun::template apply<T1, T2>".
12363	///
12364	/// \param S The scope in which this typename type occurs.
12365	/// \param TypenameLoc the location of the 'typename' keyword
12366	/// \param SS the nested-name-specifier following the typename (e.g., 'T::').
12367	/// \param TemplateLoc the location of the 'template' keyword, if any.
12368	/// \param TemplateName The template name.
12369	/// \param TemplateII The identifier used to name the template.
12370	/// \param TemplateIILoc The location of the template name.
12371	/// \param LAngleLoc The location of the opening angle bracket ('<').
12372	/// \param TemplateArgs The template arguments.
12373	/// \param RAngleLoc The location of the closing angle bracket ('>').
12374	TypeResult
12375	ActOnTypenameType(Scope *S, SourceLocation TypenameLoc,
12376	const CXXScopeSpec &SS, SourceLocation TemplateLoc,
12377	TemplateTy TemplateName, const IdentifierInfo *TemplateII,
12378	SourceLocation TemplateIILoc, SourceLocation LAngleLoc,
12379	ASTTemplateArgsPtr TemplateArgs, SourceLocation RAngleLoc);
12380
12381	QualType CheckTypenameType(ElaboratedTypeKeyword Keyword,
12382	SourceLocation KeywordLoc,
12383	NestedNameSpecifierLoc QualifierLoc,
12384	const IdentifierInfo &II, SourceLocation IILoc,
12385	TypeSourceInfo *TSI, bool* DeducedTSTContext);
12386
12387	QualType CheckTypenameType(ElaboratedTypeKeyword Keyword,
12388	SourceLocation KeywordLoc,
12389	NestedNameSpecifierLoc QualifierLoc,
12390	const IdentifierInfo &II, SourceLocation IILoc,
12391	bool DeducedTSTContext = true);
12392
12393	/// Rebuilds a type within the context of the current instantiation.
12394	///
12395	/// The type \p T is part of the type of an out-of-line member definition of
12396	/// a class template (or class template partial specialization) that was
12397	/// parsed and constructed before we entered the scope of the class template
12398	/// (or partial specialization thereof). This routine will rebuild that type
12399	/// now that we have entered the declarator's scope, which may produce
12400	/// different canonical types, e.g.,
12401	///
12402	/// \code
12403	/// template<typename T>
12404	/// struct X {
12405	/// typedef T pointer;*
12406	/// pointer data();
12407	/// };
12408	///
12409	/// template<typename T>
12410	/// typename X<T>::pointer X<T>::data() { ... }
12411	/// \endcode
12412	///
12413	/// Here, the type "typename X<T>::pointer" will be created as a
12414	/// DependentNameType, since we do not know that we can look into X<T> when we
12415	/// parsed the type. This function will rebuild the type, performing the
12416	/// lookup of "pointer" in X<T> and returning an ElaboratedType whose
12417	/// canonical type is the same as the canonical type of T, allowing the*
12418	/// return types of the out-of-line definition and the declaration to match.
12419	TypeSourceInfo RebuildTypeInCurrentInstantiation(TypeSourceInfo T,
12420	SourceLocation Loc,
12421	DeclarationName Name);
12422	bool RebuildNestedNameSpecifierInCurrentInstantiation(CXXScopeSpec &SS);
12423
12424	ExprResult RebuildExprInCurrentInstantiation(Expr *E);
12425
12426	/// Rebuild the template parameters now that we know we're in a current
12427	/// instantiation.
12428	bool
12429	RebuildTemplateParamsInCurrentInstantiation(TemplateParameterList *Params);
12430
12431	/// Produces a formatted string that describes the binding of
12432	/// template parameters to template arguments.
12433	std::string
12434	getTemplateArgumentBindingsText(const TemplateParameterList *Params,
12435	const TemplateArgumentList &Args);
12436
12437	std::string
12438	getTemplateArgumentBindingsText(const TemplateParameterList *Params,
12439	const TemplateArgument *Args,
12440	unsigned NumArgs);
12441
12442	void diagnoseExprIntendedAsTemplateName(Scope *S, ExprResult TemplateName,
12443	SourceLocation Less,
12444	SourceLocation Greater);
12445
12446	/// ActOnDependentIdExpression - Handle a dependent id-expression that
12447	/// was just parsed. This is only possible with an explicit scope
12448	/// specifier naming a dependent type.
12449	ExprResult ActOnDependentIdExpression(
12450	const CXXScopeSpec &SS, SourceLocation TemplateKWLoc,
12451	const DeclarationNameInfo &NameInfo, bool isAddressOfOperand,
12452	const TemplateArgumentListInfo *TemplateArgs);
12453
12454	ExprResult
12455	BuildDependentDeclRefExpr(const CXXScopeSpec &SS,
12456	SourceLocation TemplateKWLoc,
12457	const DeclarationNameInfo &NameInfo,
12458	const TemplateArgumentListInfo *TemplateArgs);
12459
12460	// Calculates whether the expression Constraint depends on an enclosing
12461	// template, for the purposes of [temp.friend] p9.
12462	// TemplateDepth is the 'depth' of the friend function, which is used to
12463	// compare whether a declaration reference is referring to a containing
12464	// template, or just the current friend function. A 'lower' TemplateDepth in
12465	// the AST refers to a 'containing' template. As the constraint is
12466	// uninstantiated, this is relative to the 'top' of the TU.
12467	bool
12468	ConstraintExpressionDependsOnEnclosingTemplate(const FunctionDecl *Friend,
12469	unsigned TemplateDepth,
12470	const Expr *Constraint);
12471
12472	/// Find the failed Boolean condition within a given Boolean
12473	/// constant expression, and describe it with a string.
12474	std::pair<Expr , std::string> findFailedBooleanCondition(Expr Cond);
12475
12476	void CheckDeductionGuideTemplate(FunctionTemplateDecl *TD);
12477
12478	ConceptDecl *ActOnStartConceptDefinition(
12479	Scope *S, MultiTemplateParamsArg TemplateParameterLists,
12480	const IdentifierInfo *Name, SourceLocation NameLoc);
12481
12482	ConceptDecl ActOnFinishConceptDefinition(Scope S, ConceptDecl *C,
12483	Expr *ConstraintExpr,
12484	const ParsedAttributesView &Attrs);
12485
12486	void CheckConceptRedefinition(ConceptDecl *NewDecl, LookupResult &Previous,
12487	bool &AddToScope);
12488	bool CheckConceptUseInDefinition(NamedDecl *Concept, SourceLocation Loc);
12489
12490	TypeResult ActOnDependentTag(Scope S, unsigned* TagSpec, TagUseKind TUK,
12491	const CXXScopeSpec &SS,
12492	const IdentifierInfo *Name,
12493	SourceLocation TagLoc, SourceLocation NameLoc);
12494
12495	void MarkAsLateParsedTemplate(FunctionDecl FD, Decl FnD,
12496	CachedTokens &Toks);
12497	void UnmarkAsLateParsedTemplate(FunctionDecl *FD);
12498	bool IsInsideALocalClassWithinATemplateFunction();
12499
12500	/// We've found a use of a templated declaration that would trigger an
12501	/// implicit instantiation. Check that any relevant explicit specializations
12502	/// and partial specializations are visible/reachable, and diagnose if not.
12503	void checkSpecializationVisibility(SourceLocation Loc, NamedDecl *Spec);
12504	void checkSpecializationReachability(SourceLocation Loc, NamedDecl *Spec);
12505
12506	///@}
12507
12508	//
12509	//
12510	// -------------------------------------------------------------------------
12511	//
12512	//
12513
12514	/// \name C++ Template Argument Deduction
12515	/// Implementations are in SemaTemplateDeduction.cpp
12516	///@{
12517
12518	public:
12519	class SFINAETrap;
12520
12521	struct SFINAEContextBase {
12522	SFINAEContextBase(Sema &S, SFINAETrap *Cur)
12523	: S(S), Prev(std::exchange(obj&: S.CurrentSFINAEContext, new_val&: Cur)) {}
12524
12525	protected:
12526	Sema &S;
12527	~SFINAEContextBase() { S.CurrentSFINAEContext = Prev; }
12528	SFINAEContextBase(const SFINAEContextBase &) = delete;
12529	SFINAEContextBase &operator=(const SFINAEContextBase &) = delete;
12530
12531	private:
12532	SFINAETrap *Prev;
12533	};
12534
12535	struct NonSFINAEContext : SFINAEContextBase {
12536	NonSFINAEContext(Sema &S) : SFINAEContextBase (S, nullptr) {}
12537	};
12538
12539	/// RAII class used to determine whether SFINAE has
12540	/// trapped any errors that occur during template argument
12541	/// deduction.
12542	class SFINAETrap : SFINAEContextBase {
12543	bool HasErrorOcurred = false;
12544	bool WithAccessChecking = false;
12545	bool PrevLastDiagnosticIgnored =
12546	S.getDiagnostics().isLastDiagnosticIgnored();
12547	sema::TemplateDeductionInfo DeductionInfo = nullptr*;
12548
12549	SFINAETrap(Sema &S, sema::TemplateDeductionInfo *Info,
12550	bool WithAccessChecking)
12551	: SFINAEContextBase (S, this), WithAccessChecking(WithAccessChecking),
12552	DeductionInfo(Info) {}
12553
12554	public:
12555	/// \param WithAccessChecking If true, discard all diagnostics (from the
12556	/// immediate context) instead of adding them to the currently active
12557	/// \ref TemplateDeductionInfo.
12558	explicit SFINAETrap(Sema &S, bool WithAccessChecking = false)
12559	: SFINAETrap (S, /Info=/nullptr, WithAccessChecking) {}
12560
12561	SFINAETrap(Sema &S, sema::TemplateDeductionInfo &Info)
12562	: SFINAETrap (S, &Info, /WithAccessChecking=/false) {}
12563
12564	~SFINAETrap() {
12565	S.getDiagnostics().setLastDiagnosticIgnored(PrevLastDiagnosticIgnored);
12566	}
12567
12568	SFINAETrap(const SFINAETrap &) = delete;
12569	SFINAETrap &operator=(const SFINAETrap &) = delete;
12570
12571	sema::TemplateDeductionInfo getDeductionInfo() const* {
12572	return DeductionInfo;
12573	}
12574
12575	/// Determine whether any SFINAE errors have been trapped.
12576	bool hasErrorOccurred() const { return HasErrorOcurred; }
12577	void setErrorOccurred() { HasErrorOcurred = true; }
12578
12579	bool withAccessChecking() const { return WithAccessChecking; }
12580	};
12581
12582	/// RAII class used to indicate that we are performing provisional
12583	/// semantic analysis to determine the validity of a construct, so
12584	/// typo-correction and diagnostics in the immediate context (not within
12585	/// implicitly-instantiated templates) should be suppressed.
12586	class TentativeAnalysisScope {
12587	Sema &SemaRef;
12588	// FIXME: Using a SFINAETrap for this is a hack.
12589	SFINAETrap Trap;
12590	bool PrevDisableTypoCorrection;
12591
12592	public:
12593	explicit TentativeAnalysisScope(Sema &SemaRef)
12594	: SemaRef(SemaRef), Trap (SemaRef, /ForValidityCheck=/true),
12595	PrevDisableTypoCorrection(SemaRef.DisableTypoCorrection) {
12596	SemaRef.DisableTypoCorrection = true;
12597	}
12598	~TentativeAnalysisScope() {
12599	SemaRef.DisableTypoCorrection = PrevDisableTypoCorrection;
12600	}
12601
12602	TentativeAnalysisScope(const TentativeAnalysisScope &) = delete;
12603	TentativeAnalysisScope &operator=(const TentativeAnalysisScope &) = delete;
12604	};
12605
12606	/// For each declaration that involved template argument deduction, the
12607	/// set of diagnostics that were suppressed during that template argument
12608	/// deduction.
12609	///
12610	/// FIXME: Serialize this structure to the AST file.
12611	typedef llvm::DenseMap<Decl *, SmallVector<PartialDiagnosticAt, `1`>>
12612	SuppressedDiagnosticsMap;
12613	SuppressedDiagnosticsMap SuppressedDiagnostics;
12614
12615	/// Compare types for equality with respect to possibly compatible
12616	/// function types (noreturn adjustment, implicit calling conventions). If any
12617	/// of parameter and argument is not a function, just perform type comparison.
12618	///
12619	/// \param P the template parameter type.
12620	///
12621	/// \param A the argument type.
12622	bool isSameOrCompatibleFunctionType(QualType Param, QualType Arg);
12623
12624	/// Allocate a TemplateArgumentLoc where all locations have
12625	/// been initialized to the given location.
12626	///
12627	/// \param Arg The template argument we are producing template argument
12628	/// location information for.
12629	///
12630	/// \param NTTPType For a declaration template argument, the type of
12631	/// the non-type template parameter that corresponds to this template
12632	/// argument. Can be null if no type sugar is available to add to the
12633	/// type from the template argument.
12634	///
12635	/// \param Loc The source location to use for the resulting template
12636	/// argument.
12637	TemplateArgumentLoc
12638	getTrivialTemplateArgumentLoc(const TemplateArgument &Arg, QualType NTTPType,
12639	SourceLocation Loc,
12640	NamedDecl TemplateParam = nullptr*);
12641
12642	/// Get a template argument mapping the given template parameter to itself,
12643	/// e.g. for X in \c template<int X>, this would return an expression template
12644	/// argument referencing X.
12645	TemplateArgumentLoc getIdentityTemplateArgumentLoc(NamedDecl *Param,
12646	SourceLocation Location);
12647
12648	/// Adjust the type \p ArgFunctionType to match the calling convention,
12649	/// noreturn, and optionally the exception specification of \p FunctionType.
12650	/// Deduction often wants to ignore these properties when matching function
12651	/// types.
12652	QualType adjustCCAndNoReturn(QualType ArgFunctionType, QualType FunctionType,
12653	bool AdjustExceptionSpec = false);
12654
12655	TemplateDeductionResult
12656	DeduceTemplateArguments(ClassTemplatePartialSpecializationDecl *Partial,
12657	ArrayRef<TemplateArgument> TemplateArgs,
12658	sema::TemplateDeductionInfo &Info);
12659
12660	TemplateDeductionResult
12661	DeduceTemplateArguments(VarTemplatePartialSpecializationDecl *Partial,
12662	ArrayRef<TemplateArgument> TemplateArgs,
12663	sema::TemplateDeductionInfo &Info);
12664
12665	/// Deduce the template arguments of the given template from \p FromType.
12666	/// Used to implement the IsDeducible constraint for alias CTAD per C++
12667	/// [over.match.class.deduct]p4.
12668	///
12669	/// It only supports class or type alias templates.
12670	TemplateDeductionResult
12671	DeduceTemplateArgumentsFromType(TemplateDecl *TD, QualType FromType,
12672	sema::TemplateDeductionInfo &Info);
12673
12674	TemplateDeductionResult DeduceTemplateArguments(
12675	TemplateParameterList *TemplateParams, ArrayRef<TemplateArgument> Ps,
12676	ArrayRef<TemplateArgument> As, sema::TemplateDeductionInfo &Info,
12677	SmallVectorImpl<DeducedTemplateArgument> &Deduced,
12678	bool NumberOfArgumentsMustMatch);
12679
12680	/// Substitute the explicitly-provided template arguments into the
12681	/// given function template according to C++ [temp.arg.explicit].
12682	///
12683	/// \param FunctionTemplate the function template into which the explicit
12684	/// template arguments will be substituted.
12685	///
12686	/// \param ExplicitTemplateArgs the explicitly-specified template
12687	/// arguments.
12688	///
12689	/// \param Deduced the deduced template arguments, which will be populated
12690	/// with the converted and checked explicit template arguments.
12691	///
12692	/// \param ParamTypes will be populated with the instantiated function
12693	/// parameters.
12694	///
12695	/// \param FunctionType if non-NULL, the result type of the function template
12696	/// will also be instantiated and the pointed-to value will be updated with
12697	/// the instantiated function type.
12698	///
12699	/// \param Info if substitution fails for any reason, this object will be
12700	/// populated with more information about the failure.
12701	///
12702	/// \returns TemplateDeductionResult::Success if substitution was successful,
12703	/// or some failure condition.
12704	TemplateDeductionResult SubstituteExplicitTemplateArguments(
12705	FunctionTemplateDecl *FunctionTemplate,
12706	TemplateArgumentListInfo &ExplicitTemplateArgs,
12707	SmallVectorImpl<DeducedTemplateArgument> &Deduced,
12708	SmallVectorImpl<QualType> &ParamTypes, QualType *FunctionType,
12709	sema::TemplateDeductionInfo &Info);
12710
12711	/// brief A function argument from which we performed template argument
12712	// deduction for a call.
12713	struct OriginalCallArg {
12714	OriginalCallArg(QualType OriginalParamType, bool DecomposedParam,
12715	unsigned ArgIdx, QualType OriginalArgType)
12716	: OriginalParamType (OriginalParamType),
12717	DecomposedParam(DecomposedParam), ArgIdx(ArgIdx),
12718	OriginalArgType (OriginalArgType) {}
12719
12720	QualType OriginalParamType;
12721	bool DecomposedParam;
12722	unsigned ArgIdx;
12723	QualType OriginalArgType;
12724	};
12725
12726	/// Finish template argument deduction for a function template,
12727	/// checking the deduced template arguments for completeness and forming
12728	/// the function template specialization.
12729	///
12730	/// \param OriginalCallArgs If non-NULL, the original call arguments against
12731	/// which the deduced argument types should be compared.
12732	/// \param CheckNonDependent Callback before substituting into the declaration
12733	/// with the deduced template arguments.
12734	/// \param OnlyInitializeNonUserDefinedConversions is used as a workaround for
12735	/// some breakages introduced by CWG2369, where non-user-defined conversions
12736	/// are checked first before the constraints.
12737	TemplateDeductionResult FinishTemplateArgumentDeduction(
12738	FunctionTemplateDecl *FunctionTemplate,
12739	SmallVectorImpl<DeducedTemplateArgument> &Deduced,
12740	unsigned NumExplicitlySpecified, FunctionDecl *&Specialization,
12741	sema::TemplateDeductionInfo &Info,
12742	SmallVectorImpl<OriginalCallArg> const *OriginalCallArgs,
12743	bool PartialOverloading, bool PartialOrdering,
12744	bool ForOverloadSetAddressResolution,
12745	llvm::function_ref<bool(bool)> CheckNonDependent =
12746	[](bool /OnlyInitializeNonUserDefinedConversions/) {
12747	return false;
12748	});
12749
12750	/// Perform template argument deduction from a function call
12751	/// (C++ [temp.deduct.call]).
12752	///
12753	/// \param FunctionTemplate the function template for which we are performing
12754	/// template argument deduction.
12755	///
12756	/// \param ExplicitTemplateArgs the explicit template arguments provided
12757	/// for this call.
12758	///
12759	/// \param Args the function call arguments
12760	///
12761	/// \param Specialization if template argument deduction was successful,
12762	/// this will be set to the function template specialization produced by
12763	/// template argument deduction.
12764	///
12765	/// \param Info the argument will be updated to provide additional information
12766	/// about template argument deduction.
12767	///
12768	/// \param CheckNonDependent A callback to invoke to check conversions for
12769	/// non-dependent parameters, between deduction and substitution, per DR1391.
12770	/// If this returns true, substitution will be skipped and we return
12771	/// TemplateDeductionResult::NonDependentConversionFailure. The callback is
12772	/// passed the parameter types (after substituting explicit template
12773	/// arguments).
12774	///
12775	/// \returns the result of template argument deduction.
12776	TemplateDeductionResult DeduceTemplateArguments(
12777	FunctionTemplateDecl *FunctionTemplate,
12778	TemplateArgumentListInfo ExplicitTemplateArgs, ArrayRef<Expr > Args,
12779	FunctionDecl *&Specialization, sema::TemplateDeductionInfo &Info,
12780	bool PartialOverloading, bool AggregateDeductionCandidate,
12781	bool PartialOrdering, QualType ObjectType,
12782	Expr::Classification ObjectClassification,
12783	bool ForOverloadSetAddressResolution,
12784	llvm::function_ref<bool(ArrayRef<QualType>, bool)> CheckNonDependent);
12785
12786	/// Deduce template arguments when taking the address of a function
12787	/// template (C++ [temp.deduct.funcaddr]) or matching a specialization to
12788	/// a template.
12789	///
12790	/// \param FunctionTemplate the function template for which we are performing
12791	/// template argument deduction.
12792	///
12793	/// \param ExplicitTemplateArgs the explicitly-specified template
12794	/// arguments.
12795	///
12796	/// \param ArgFunctionType the function type that will be used as the
12797	/// "argument" type (A) when performing template argument deduction from the
12798	/// function template's function type. This type may be NULL, if there is no
12799	/// argument type to compare against, in C++0x [temp.arg.explicit]p3.
12800	///
12801	/// \param Specialization if template argument deduction was successful,
12802	/// this will be set to the function template specialization produced by
12803	/// template argument deduction.
12804	///
12805	/// \param Info the argument will be updated to provide additional information
12806	/// about template argument deduction.
12807	///
12808	/// \param IsAddressOfFunction If \c true, we are deducing as part of taking
12809	/// the address of a function template per [temp.deduct.funcaddr] and
12810	/// [over.over]. If \c false, we are looking up a function template
12811	/// specialization based on its signature, per [temp.deduct.decl].
12812	///
12813	/// \returns the result of template argument deduction.
12814	TemplateDeductionResult DeduceTemplateArguments(
12815	FunctionTemplateDecl *FunctionTemplate,
12816	TemplateArgumentListInfo *ExplicitTemplateArgs, QualType ArgFunctionType,
12817	FunctionDecl *&Specialization, sema::TemplateDeductionInfo &Info,
12818	bool IsAddressOfFunction = false);
12819
12820	/// Deduce template arguments for a templated conversion
12821	/// function (C++ [temp.deduct.conv]) and, if successful, produce a
12822	/// conversion function template specialization.
12823	TemplateDeductionResult DeduceTemplateArguments(
12824	FunctionTemplateDecl *FunctionTemplate, QualType ObjectType,
12825	Expr::Classification ObjectClassification, QualType ToType,
12826	CXXConversionDecl *&Specialization, sema::TemplateDeductionInfo &Info);
12827
12828	/// Deduce template arguments for a function template when there is
12829	/// nothing to deduce against (C++0x [temp.arg.explicit]p3).
12830	///
12831	/// \param FunctionTemplate the function template for which we are performing
12832	/// template argument deduction.
12833	///
12834	/// \param ExplicitTemplateArgs the explicitly-specified template
12835	/// arguments.
12836	///
12837	/// \param Specialization if template argument deduction was successful,
12838	/// this will be set to the function template specialization produced by
12839	/// template argument deduction.
12840	///
12841	/// \param Info the argument will be updated to provide additional information
12842	/// about template argument deduction.
12843	///
12844	/// \param IsAddressOfFunction If \c true, we are deducing as part of taking
12845	/// the address of a function template in a context where we do not have a
12846	/// target type, per [over.over]. If \c false, we are looking up a function
12847	/// template specialization based on its signature, which only happens when
12848	/// deducing a function parameter type from an argument that is a template-id
12849	/// naming a function template specialization.
12850	///
12851	/// \returns the result of template argument deduction.
12852	TemplateDeductionResult
12853	DeduceTemplateArguments(FunctionTemplateDecl *FunctionTemplate,
12854	TemplateArgumentListInfo *ExplicitTemplateArgs,
12855	FunctionDecl *&Specialization,
12856	sema::TemplateDeductionInfo &Info,
12857	bool IsAddressOfFunction = false);
12858
12859	/// Substitute Replacement for \p auto in \p TypeWithAuto
12860	QualType SubstAutoType(QualType TypeWithAuto, QualType Replacement);
12861	/// Substitute Replacement for auto in TypeWithAuto
12862	TypeSourceInfo SubstAutoTypeSourceInfo(TypeSourceInfo TypeWithAuto,
12863	QualType Replacement);
12864
12865	// Substitute auto in TypeWithAuto for a Dependent auto type
12866	QualType SubstAutoTypeDependent(QualType TypeWithAuto);
12867
12868	// Substitute auto in TypeWithAuto for a Dependent auto type
12869	TypeSourceInfo *
12870	SubstAutoTypeSourceInfoDependent(TypeSourceInfo *TypeWithAuto);
12871
12872	/// Completely replace the \c auto in \p TypeWithAuto by
12873	/// \p Replacement. This does not retain any \c auto type sugar.
12874	QualType ReplaceAutoType(QualType TypeWithAuto, QualType Replacement);
12875	TypeSourceInfo ReplaceAutoTypeSourceInfo(TypeSourceInfo TypeWithAuto,
12876	QualType Replacement);
12877
12878	/// Deduce the type for an auto type-specifier (C++11 [dcl.spec.auto]p6)
12879	///
12880	/// Note that this is done even if the initializer is dependent. (This is
12881	/// necessary to support partial ordering of templates using 'auto'.)
12882	/// A dependent type will be produced when deducing from a dependent type.
12883	///
12884	/// \param Type the type pattern using the auto type-specifier.
12885	/// \param Init the initializer for the variable whose type is to be deduced.
12886	/// \param Result if type deduction was successful, this will be set to the
12887	/// deduced type.
12888	/// \param Info the argument will be updated to provide additional information
12889	/// about template argument deduction.
12890	/// \param DependentDeduction Set if we should permit deduction in
12891	/// dependent cases. This is necessary for template partial ordering
12892	/// with 'auto' template parameters. The template parameter depth to be
12893	/// used should be specified in the 'Info' parameter.
12894	/// \param IgnoreConstraints Set if we should not fail if the deduced type
12895	/// does not satisfy the type-constraint in the auto
12896	/// type.
12897	TemplateDeductionResult
12898	DeduceAutoType(TypeLoc AutoTypeLoc, Expr *Initializer, QualType &Result,
12899	sema::TemplateDeductionInfo &Info,
12900	bool DependentDeduction = false,
12901	bool IgnoreConstraints = false,
12902	TemplateSpecCandidateSet FailedTSC = nullptr*);
12903	void DiagnoseAutoDeductionFailure(const VarDecl VDecl, const* Expr *Init);
12904	bool DeduceReturnType(FunctionDecl *FD, SourceLocation Loc,
12905	bool Diagnose = true);
12906
12907	bool CheckIfFunctionSpecializationIsImmediate(FunctionDecl *FD,
12908	SourceLocation Loc);
12909
12910	/// Returns the more specialized class template partial specialization
12911	/// according to the rules of partial ordering of class template partial
12912	/// specializations (C++ [temp.class.order]).
12913	///
12914	/// \param PS1 the first class template partial specialization
12915	///
12916	/// \param PS2 the second class template partial specialization
12917	///
12918	/// \returns the more specialized class template partial specialization. If
12919	/// neither partial specialization is more specialized, returns NULL.
12920	ClassTemplatePartialSpecializationDecl *
12921	getMoreSpecializedPartialSpecialization(
12922	ClassTemplatePartialSpecializationDecl *PS1,
12923	ClassTemplatePartialSpecializationDecl *PS2, SourceLocation Loc);
12924
12925	bool isMoreSpecializedThanPrimary(ClassTemplatePartialSpecializationDecl *T,
12926	sema::TemplateDeductionInfo &Info);
12927
12928	VarTemplatePartialSpecializationDecl *getMoreSpecializedPartialSpecialization(
12929	VarTemplatePartialSpecializationDecl *PS1,
12930	VarTemplatePartialSpecializationDecl *PS2, SourceLocation Loc);
12931
12932	bool isMoreSpecializedThanPrimary(VarTemplatePartialSpecializationDecl *T,
12933	sema::TemplateDeductionInfo &Info);
12934
12935	bool isTemplateTemplateParameterAtLeastAsSpecializedAs(
12936	TemplateParameterList PParam, TemplateDecl PArg, TemplateDecl *AArg,
12937	const DefaultArguments &DefaultArgs, SourceLocation ArgLoc,
12938	bool PartialOrdering, bool *StrictPackMatch);
12939
12940	/// Mark which template parameters are used in a given expression.
12941	///
12942	/// \param E the expression from which template parameters will be deduced.
12943	///
12944	/// \param Used a bit vector whose elements will be set to \c true
12945	/// to indicate when the corresponding template parameter will be
12946	/// deduced.
12947	void MarkUsedTemplateParameters(const Expr E, bool* OnlyDeduced,
12948	unsigned Depth, llvm::SmallBitVector &Used);
12949
12950	/// Mark which template parameters are named in a given expression.
12951	///
12952	/// Unlike MarkUsedTemplateParameters, this excludes parameter that
12953	/// are used but not directly named by an expression - i.e. it excludes
12954	/// any template parameter that denotes the type of a referenced NTTP.
12955	///
12956	/// \param Used a bit vector whose elements will be set to \c true
12957	/// to indicate when the corresponding template parameter will be
12958	/// deduced.
12959	void MarkUsedTemplateParametersForSubsumptionParameterMapping(
12960	const Expr E, unsigned* Depth, llvm::SmallBitVector &Used);
12961
12962	/// Mark which template parameters can be deduced from a given
12963	/// template argument list.
12964	///
12965	/// \param TemplateArgs the template argument list from which template
12966	/// parameters will be deduced.
12967	///
12968	/// \param Used a bit vector whose elements will be set to \c true
12969	/// to indicate when the corresponding template parameter will be
12970	/// deduced.
12971	void MarkUsedTemplateParameters(const TemplateArgumentList &TemplateArgs,
12972	bool OnlyDeduced, unsigned Depth,
12973	llvm::SmallBitVector &Used);
12974
12975	void MarkUsedTemplateParameters(ArrayRef<TemplateArgument> TemplateArgs,
12976	unsigned Depth, llvm::SmallBitVector &Used);
12977
12978	void MarkUsedTemplateParameters(ArrayRef<TemplateArgumentLoc> TemplateArgs,
12979	unsigned Depth, llvm::SmallBitVector &Used);
12980
12981	void
12982	MarkDeducedTemplateParameters(const FunctionTemplateDecl *FunctionTemplate,
12983	llvm::SmallBitVector &Deduced) {
12984	return MarkDeducedTemplateParameters(Ctx&: Context, FunctionTemplate, Deduced);
12985	}
12986
12987	/// Marks all of the template parameters that will be deduced by a
12988	/// call to the given function template.
12989	static void
12990	MarkDeducedTemplateParameters(ASTContext &Ctx,
12991	const FunctionTemplateDecl *FunctionTemplate,
12992	llvm::SmallBitVector &Deduced);
12993
12994	/// Returns the more specialized function template according
12995	/// to the rules of function template partial ordering (C++
12996	/// [temp.func.order]).
12997	///
12998	/// \param FT1 the first function template
12999	///
13000	/// \param FT2 the second function template
13001	///
13002	/// \param TPOC the context in which we are performing partial ordering of
13003	/// function templates.
13004	///
13005	/// \param NumCallArguments1 The number of arguments in the call to FT1, used
13006	/// only when \c TPOC is \c TPOC_Call. Does not include the object argument
13007	/// when calling a member function.
13008	///
13009	/// \param RawObj1Ty The type of the object parameter of FT1 if a member
13010	/// function only used if \c TPOC is \c TPOC_Call and FT1 is a Function
13011	/// template from a member function
13012	///
13013	/// \param RawObj2Ty The type of the object parameter of FT2 if a member
13014	/// function only used if \c TPOC is \c TPOC_Call and FT2 is a Function
13015	/// template from a member function
13016	///
13017	/// \param Reversed If \c true, exactly one of FT1 and FT2 is an overload
13018	/// candidate with a reversed parameter order. In this case, the corresponding
13019	/// P/A pairs between FT1 and FT2 are reversed.
13020	///
13021	/// \returns the more specialized function template. If neither
13022	/// template is more specialized, returns NULL.
13023	FunctionTemplateDecl *getMoreSpecializedTemplate(
13024	FunctionTemplateDecl FT1, FunctionTemplateDecl FT2, SourceLocation Loc,
13025	TemplatePartialOrderingContext TPOC, unsigned NumCallArguments1,
13026	QualType RawObj1Ty = {}, QualType RawObj2Ty = {}, bool Reversed = false,
13027	bool PartialOverloading = false);
13028
13029	/// Retrieve the most specialized of the given function template
13030	/// specializations.
13031	///
13032	/// \param SpecBegin the start iterator of the function template
13033	/// specializations that we will be comparing.
13034	///
13035	/// \param SpecEnd the end iterator of the function template
13036	/// specializations, paired with \p SpecBegin.
13037	///
13038	/// \param Loc the location where the ambiguity or no-specializations
13039	/// diagnostic should occur.
13040	///
13041	/// \param NoneDiag partial diagnostic used to diagnose cases where there are
13042	/// no matching candidates.
13043	///
13044	/// \param AmbigDiag partial diagnostic used to diagnose an ambiguity, if one
13045	/// occurs.
13046	///
13047	/// \param CandidateDiag partial diagnostic used for each function template
13048	/// specialization that is a candidate in the ambiguous ordering. One
13049	/// parameter in this diagnostic should be unbound, which will correspond to
13050	/// the string describing the template arguments for the function template
13051	/// specialization.
13052	///
13053	/// \returns the most specialized function template specialization, if
13054	/// found. Otherwise, returns SpecEnd.
13055	UnresolvedSetIterator
13056	getMostSpecialized(UnresolvedSetIterator SBegin, UnresolvedSetIterator SEnd,
13057	TemplateSpecCandidateSet &FailedCandidates,
13058	SourceLocation Loc, const PartialDiagnostic &NoneDiag,
13059	const PartialDiagnostic &AmbigDiag,
13060	const PartialDiagnostic &CandidateDiag,
13061	bool Complain = true, QualType TargetType = QualType ());
13062
13063	/// Returns the more constrained function according to the rules of
13064	/// partial ordering by constraints (C++ [temp.constr.order]).
13065	///
13066	/// \param FD1 the first function
13067	///
13068	/// \param FD2 the second function
13069	///
13070	/// \returns the more constrained function. If neither function is
13071	/// more constrained, returns NULL.
13072	FunctionDecl getMoreConstrainedFunction(FunctionDecl FD1,
13073	FunctionDecl *FD2);
13074
13075	///@}
13076
13077	//
13078	//
13079	// -------------------------------------------------------------------------
13080	//
13081	//
13082
13083	/// \name C++ Template Deduction Guide
13084	/// Implementations are in SemaTemplateDeductionGuide.cpp
13085	///@{
13086
13087	/// Declare implicit deduction guides for a class template if we've
13088	/// not already done so.
13089	void DeclareImplicitDeductionGuides(TemplateDecl *Template,
13090	SourceLocation Loc);
13091
13092	FunctionTemplateDecl *DeclareAggregateDeductionGuideFromInitList(
13093	TemplateDecl *Template, MutableArrayRef<QualType> ParamTypes,
13094	SourceLocation Loc);
13095
13096	///@}
13097
13098	//
13099	//
13100	// -------------------------------------------------------------------------
13101	//
13102	//
13103
13104	/// \name C++ Template Instantiation
13105	/// Implementations are in SemaTemplateInstantiate.cpp
13106	///@{
13107
13108	public:
13109	/// A helper class for building up ExtParameterInfos.
13110	class ExtParameterInfoBuilder {
13111	SmallVector<FunctionProtoType::ExtParameterInfo, `16`> Infos;
13112	bool HasInteresting = false;
13113
13114	public:
13115	/// Set the ExtParameterInfo for the parameter at the given index,
13116	///
13117	void set(unsigned index, FunctionProtoType::ExtParameterInfo info) {
13118	assert(Infos.size() <= index);
13119	Infos.resize(N: index);
13120	Infos.push_back(Elt: info);
13121
13122	if (!HasInteresting)
13123	HasInteresting = (info != FunctionProtoType::ExtParameterInfo ());
13124	}
13125
13126	/// Return a pointer (suitable for setting in an ExtProtoInfo) to the
13127	/// ExtParameterInfo array we've built up.
13128	const FunctionProtoType::ExtParameterInfo *
13129	getPointerOrNull(unsigned numParams) {
13130	if (!HasInteresting)
13131	return nullptr;
13132	Infos.resize(N: numParams);
13133	return Infos.data();
13134	}
13135	};
13136
13137	/// The current instantiation scope used to store local
13138	/// variables.
13139	LocalInstantiationScope *CurrentInstantiationScope;
13140
13141	typedef llvm::DenseMap<ParmVarDecl , llvm::TinyPtrVector<ParmVarDecl >>
13142	UnparsedDefaultArgInstantiationsMap;
13143
13144	/// A mapping from parameters with unparsed default arguments to the
13145	/// set of instantiations of each parameter.
13146	///
13147	/// This mapping is a temporary data structure used when parsing
13148	/// nested class templates or nested classes of class templates,
13149	/// where we might end up instantiating an inner class before the
13150	/// default arguments of its methods have been parsed.
13151	UnparsedDefaultArgInstantiationsMap UnparsedDefaultArgInstantiations;
13152
13153	using InstantiatingSpecializationsKey = llvm::PointerIntPair<Decl *, `2`>;
13154
13155	struct RecursiveInstGuard {
13156	enum class Kind {
13157	Template,
13158	DefaultArgument,
13159	ExceptionSpec,
13160	};
13161
13162	RecursiveInstGuard(Sema &S, Decl *D, Kind Kind)
13163	: S(S), Key (D->getCanonicalDecl(), unsigned(Kind)) {
13164	auto [_, Created] = S.InstantiatingSpecializations.insert(V: Key);
13165	if (!Created)
13166	Key = {};
13167	}
13168
13169	~RecursiveInstGuard() {
13170	if (Key.getOpaqueValue()) {
13171	[[maybe_unused]] bool Erased =
13172	S.InstantiatingSpecializations.erase(V: Key);
13173	assert(Erased);
13174	}
13175	}
13176
13177	RecursiveInstGuard(const RecursiveInstGuard &) = delete;
13178	RecursiveInstGuard &operator=(const RecursiveInstGuard &) = delete;
13179
13180	operator bool() const { return Key.getOpaqueValue() == nullptr; }
13181
13182	private:
13183	Sema &S;
13184	Sema::InstantiatingSpecializationsKey Key;
13185	};
13186
13187	/// A context in which code is being synthesized (where a source location
13188	/// alone is not sufficient to identify the context). This covers template
13189	/// instantiation and various forms of implicitly-generated functions.
13190	struct CodeSynthesisContext {
13191	/// The kind of template instantiation we are performing
13192	enum SynthesisKind {
13193	/// We are instantiating a template declaration. The entity is
13194	/// the declaration we're instantiating (e.g., a CXXRecordDecl).
13195	TemplateInstantiation,
13196
13197	/// We are instantiating a default argument for a template
13198	/// parameter. The Entity is the template parameter whose argument is
13199	/// being instantiated, the Template is the template, and the
13200	/// TemplateArgs/NumTemplateArguments provide the template arguments as
13201	/// specified.
13202	DefaultTemplateArgumentInstantiation,
13203
13204	/// We are instantiating a default argument for a function.
13205	/// The Entity is the ParmVarDecl, and TemplateArgs/NumTemplateArgs
13206	/// provides the template arguments as specified.
13207	DefaultFunctionArgumentInstantiation,
13208
13209	/// We are substituting explicit template arguments provided for
13210	/// a function template. The entity is a FunctionTemplateDecl.
13211	ExplicitTemplateArgumentSubstitution,
13212
13213	/// We are substituting template argument determined as part of
13214	/// template argument deduction for either a class template
13215	/// partial specialization or a function template. The
13216	/// Entity is either a {Class\|Var}TemplatePartialSpecializationDecl or
13217	/// a TemplateDecl.
13218	DeducedTemplateArgumentSubstitution,
13219
13220	/// We are substituting into a lambda expression.
13221	LambdaExpressionSubstitution,
13222
13223	/// We are substituting prior template arguments into a new
13224	/// template parameter. The template parameter itself is either a
13225	/// NonTypeTemplateParmDecl or a TemplateTemplateParmDecl.
13226	PriorTemplateArgumentSubstitution,
13227
13228	/// We are checking the validity of a default template argument that
13229	/// has been used when naming a template-id.
13230	DefaultTemplateArgumentChecking,
13231
13232	/// We are computing the exception specification for a defaulted special
13233	/// member function.
13234	ExceptionSpecEvaluation,
13235
13236	/// We are instantiating the exception specification for a function
13237	/// template which was deferred until it was needed.
13238	ExceptionSpecInstantiation,
13239
13240	/// We are instantiating a requirement of a requires expression.
13241	RequirementInstantiation,
13242
13243	/// We are checking the satisfaction of a nested requirement of a requires
13244	/// expression.
13245	NestedRequirementConstraintsCheck,
13246
13247	/// We are declaring an implicit special member function.
13248	DeclaringSpecialMember,
13249
13250	/// We are declaring an implicit 'operator==' for a defaulted
13251	/// 'operator<=>'.
13252	DeclaringImplicitEqualityComparison,
13253
13254	/// We are defining a synthesized function (such as a defaulted special
13255	/// member).
13256	DefiningSynthesizedFunction,
13257
13258	// We are checking the constraints associated with a constrained entity or
13259	// the constraint expression of a concept. This includes the checks that
13260	// atomic constraints have the type 'bool' and that they can be constant
13261	// evaluated.
13262	ConstraintsCheck,
13263
13264	// We are substituting template arguments into a constraint expression.
13265	ConstraintSubstitution,
13266
13267	// We are normalizing a constraint expression.
13268	ConstraintNormalization,
13269
13270	// Instantiating a Requires Expression parameter clause.
13271	RequirementParameterInstantiation,
13272
13273	// We are substituting into the parameter mapping of an atomic constraint
13274	// during normalization.
13275	ParameterMappingSubstitution,
13276
13277	/// We are rewriting a comparison operator in terms of an operator<=>.
13278	RewritingOperatorAsSpaceship,
13279
13280	/// We are initializing a structured binding.
13281	InitializingStructuredBinding,
13282
13283	/// We are marking a class as __dllexport.
13284	MarkingClassDllexported,
13285
13286	/// We are building an implied call from __builtin_dump_struct. The
13287	/// arguments are in CallArgs.
13288	BuildingBuiltinDumpStructCall,
13289
13290	/// Added for Template instantiation observation.
13291	/// Memoization means we are _not_ instantiating a template because
13292	/// it is already instantiated (but we entered a context where we
13293	/// would have had to if it was not already instantiated).
13294	Memoization,
13295
13296	/// We are building deduction guides for a class.
13297	BuildingDeductionGuides,
13298
13299	/// We are instantiating a type alias template declaration.
13300	TypeAliasTemplateInstantiation,
13301
13302	/// We are performing partial ordering for template template parameters.
13303	PartialOrderingTTP,
13304
13305	/// We are performing name lookup for a function template or variable
13306	/// template named 'sycl_kernel_launch'.
13307	SYCLKernelLaunchLookup,
13308
13309	/// We are performing overload resolution for a call to a function
13310	/// template or variable template named 'sycl_kernel_launch'.
13311	SYCLKernelLaunchOverloadResolution,
13312	} Kind;
13313
13314	/// Whether we're substituting into constraints.
13315	bool InConstraintSubstitution;
13316
13317	/// Whether we're substituting into the parameter mapping of a constraint.
13318	bool InParameterMappingSubstitution;
13319
13320	/// The point of instantiation or synthesis within the source code.
13321	SourceLocation PointOfInstantiation;
13322
13323	/// The entity that is being synthesized.
13324	Decl *Entity;
13325
13326	/// The template (or partial specialization) in which we are
13327	/// performing the instantiation, for substitutions of prior template
13328	/// arguments.
13329	NamedDecl *Template;
13330
13331	union {
13332	/// The list of template arguments we are substituting, if they
13333	/// are not part of the entity.
13334	const TemplateArgument *TemplateArgs;
13335
13336	/// The list of argument expressions in a synthesized call.
13337	const Expr *const *CallArgs;
13338	};
13339
13340	// FIXME: Wrap this union around more members, or perhaps store the
13341	// kind-specific members in the RAII object owning the context.
13342	union {
13343	/// The number of template arguments in TemplateArgs.
13344	unsigned NumTemplateArgs;
13345
13346	/// The number of expressions in CallArgs.
13347	unsigned NumCallArgs;
13348
13349	/// The special member being declared or defined.
13350	CXXSpecialMemberKind SpecialMember;
13351	};
13352
13353	ArrayRef<TemplateArgument> template_arguments() const {
13354	assert(Kind != DeclaringSpecialMember);
13355	return {TemplateArgs, NumTemplateArgs};
13356	}
13357
13358	/// The source range that covers the construct that cause
13359	/// the instantiation, e.g., the template-id that causes a class
13360	/// template instantiation.
13361	SourceRange InstantiationRange;
13362
13363	CodeSynthesisContext()
13364	: Kind(TemplateInstantiation), InConstraintSubstitution(false),
13365	InParameterMappingSubstitution(false), Entity(nullptr),
13366	Template(nullptr), TemplateArgs(nullptr), NumTemplateArgs(`0`) {}
13367
13368	/// Determines whether this template is an actual instantiation
13369	/// that should be counted toward the maximum instantiation depth.
13370	bool isInstantiationRecord() const;
13371	};
13372
13373	/// A stack object to be created when performing template
13374	/// instantiation.
13375	///
13376	/// Construction of an object of type \c InstantiatingTemplate
13377	/// pushes the current instantiation onto the stack of active
13378	/// instantiations. If the size of this stack exceeds the maximum
13379	/// number of recursive template instantiations, construction
13380	/// produces an error and evaluates true.
13381	///
13382	/// Destruction of this object will pop the named instantiation off
13383	/// the stack.
13384	struct InstantiatingTemplate {
13385	/// Note that we are instantiating a class template,
13386	/// function template, variable template, alias template,
13387	/// or a member thereof.
13388	InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
13389	Decl *Entity,
13390	SourceRange InstantiationRange = SourceRange ());
13391
13392	struct ExceptionSpecification {};
13393	/// Note that we are instantiating an exception specification
13394	/// of a function template.
13395	InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
13396	FunctionDecl *Entity, ExceptionSpecification,
13397	SourceRange InstantiationRange = SourceRange ());
13398
13399	/// Note that we are instantiating a type alias template declaration.
13400	InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
13401	TypeAliasTemplateDecl *Entity,
13402	ArrayRef<TemplateArgument> TemplateArgs,
13403	SourceRange InstantiationRange = SourceRange ());
13404
13405	/// Note that we are instantiating a default argument in a
13406	/// template-id.
13407	InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
13408	TemplateParameter Param, TemplateDecl *Template,
13409	ArrayRef<TemplateArgument> TemplateArgs,
13410	SourceRange InstantiationRange = SourceRange ());
13411
13412	/// Note that we are substituting either explicitly-specified or
13413	/// deduced template arguments during function template argument deduction.
13414	InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
13415	FunctionTemplateDecl *FunctionTemplate,
13416	ArrayRef<TemplateArgument> TemplateArgs,
13417	CodeSynthesisContext::SynthesisKind Kind,
13418	SourceRange InstantiationRange = SourceRange ());
13419
13420	/// Note that we are instantiating as part of template
13421	/// argument deduction for a class template declaration.
13422	InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
13423	TemplateDecl *Template,
13424	ArrayRef<TemplateArgument> TemplateArgs,
13425	SourceRange InstantiationRange = SourceRange ());
13426
13427	/// Note that we are instantiating as part of template
13428	/// argument deduction for a class template partial
13429	/// specialization.
13430	InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
13431	ClassTemplatePartialSpecializationDecl *PartialSpec,
13432	ArrayRef<TemplateArgument> TemplateArgs,
13433	SourceRange InstantiationRange = SourceRange ());
13434
13435	/// Note that we are instantiating as part of template
13436	/// argument deduction for a variable template partial
13437	/// specialization.
13438	InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
13439	VarTemplatePartialSpecializationDecl *PartialSpec,
13440	ArrayRef<TemplateArgument> TemplateArgs,
13441	SourceRange InstantiationRange = SourceRange ());
13442
13443	/// Note that we are instantiating a default argument for a function
13444	/// parameter.
13445	InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
13446	ParmVarDecl *Param,
13447	ArrayRef<TemplateArgument> TemplateArgs,
13448	SourceRange InstantiationRange = SourceRange ());
13449
13450	/// Note that we are substituting prior template arguments into a
13451	/// non-type parameter.
13452	InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
13453	NamedDecl Template, NonTypeTemplateParmDecl Param,
13454	ArrayRef<TemplateArgument> TemplateArgs,
13455	SourceRange InstantiationRange);
13456
13457	/// Note that we are substituting prior template arguments into a
13458	/// template template parameter.
13459	InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
13460	NamedDecl Template, TemplateTemplateParmDecl Param,
13461	ArrayRef<TemplateArgument> TemplateArgs,
13462	SourceRange InstantiationRange);
13463
13464	/// Note that we are checking the default template argument
13465	/// against the template parameter for a given template-id.
13466	InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
13467	TemplateDecl Template, NamedDecl Param,
13468	ArrayRef<TemplateArgument> TemplateArgs,
13469	SourceRange InstantiationRange);
13470
13471	struct ConstraintsCheck {};
13472	/// \brief Note that we are checking the constraints associated with some
13473	/// constrained entity (a concept declaration or a template with associated
13474	/// constraints).
13475	InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
13476	ConstraintsCheck, NamedDecl *Template,
13477	ArrayRef<TemplateArgument> TemplateArgs,
13478	SourceRange InstantiationRange);
13479
13480	struct ConstraintSubstitution {};
13481	/// \brief Note that we are checking a constraint expression associated
13482	/// with a template declaration or as part of the satisfaction check of a
13483	/// concept.
13484	InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
13485	ConstraintSubstitution, NamedDecl *Template,
13486	SourceRange InstantiationRange);
13487
13488	struct ConstraintNormalization {};
13489	/// \brief Note that we are normalizing a constraint expression.
13490	InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
13491	ConstraintNormalization, NamedDecl *Template,
13492	SourceRange InstantiationRange);
13493
13494	struct ParameterMappingSubstitution {};
13495	/// \brief Note that we are subtituting into the parameter mapping of an
13496	/// atomic constraint during constraint normalization.
13497	InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
13498	ParameterMappingSubstitution, NamedDecl *Template,
13499	SourceRange InstantiationRange);
13500
13501	/// \brief Note that we are substituting template arguments into a part of
13502	/// a requirement of a requires expression.
13503	InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
13504	concepts::Requirement *Req,
13505	SourceRange InstantiationRange = SourceRange ());
13506
13507	/// \brief Note that we are checking the satisfaction of the constraint
13508	/// expression inside of a nested requirement.
13509	InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
13510	concepts::NestedRequirement *Req, ConstraintsCheck,
13511	SourceRange InstantiationRange = SourceRange ());
13512
13513	/// \brief Note that we are checking a requires clause.
13514	InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
13515	const RequiresExpr *E,
13516	SourceRange InstantiationRange);
13517
13518	struct BuildingDeductionGuidesTag {};
13519	/// \brief Note that we are building deduction guides.
13520	InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
13521	TemplateDecl *Entity, BuildingDeductionGuidesTag,
13522	SourceRange InstantiationRange = SourceRange ());
13523
13524	struct PartialOrderingTTP {};
13525	/// \brief Note that we are partial ordering template template parameters.
13526	InstantiatingTemplate(Sema &SemaRef, SourceLocation ArgLoc,
13527	PartialOrderingTTP, TemplateDecl *PArg,
13528	SourceRange InstantiationRange = SourceRange ());
13529
13530	/// Note that we have finished instantiating this template.
13531	void Clear();
13532
13533	~InstantiatingTemplate() { Clear(); }
13534
13535	/// Determines whether we have exceeded the maximum
13536	/// recursive template instantiations.
13537	bool isInvalid() const { return Invalid; }
13538
13539	private:
13540	Sema &SemaRef;
13541	bool Invalid;
13542
13543	InstantiatingTemplate(Sema &SemaRef,
13544	CodeSynthesisContext::SynthesisKind Kind,
13545	SourceLocation PointOfInstantiation,
13546	SourceRange InstantiationRange, Decl *Entity,
13547	NamedDecl Template = nullptr*,
13548	ArrayRef<TemplateArgument> TemplateArgs = {});
13549
13550	InstantiatingTemplate(const InstantiatingTemplate &) = delete;
13551
13552	InstantiatingTemplate &operator=(const InstantiatingTemplate &) = delete;
13553	};
13554
13555	bool SubstTemplateArgument(const TemplateArgumentLoc &Input,
13556	const MultiLevelTemplateArgumentList &TemplateArgs,
13557	TemplateArgumentLoc &Output,
13558	SourceLocation Loc = {},
13559	const DeclarationName &Entity = {});
13560	bool
13561	SubstTemplateArguments(ArrayRef<TemplateArgumentLoc> Args,
13562	const MultiLevelTemplateArgumentList &TemplateArgs,
13563	TemplateArgumentListInfo &Outputs);
13564
13565	/// Substitute concept template arguments in the constraint expression
13566	/// of a concept-id. This is used to implement [temp.constr.normal].
13567	ExprResult
13568	SubstConceptTemplateArguments(const ConceptSpecializationExpr *CSE,
13569	const Expr *ConstraintExpr,
13570	const MultiLevelTemplateArgumentList &MLTAL);
13571
13572	bool SubstTemplateArgumentsInParameterMapping(
13573	ArrayRef<TemplateArgumentLoc> Args, SourceLocation BaseLoc,
13574	const MultiLevelTemplateArgumentList &TemplateArgs,
13575	TemplateArgumentListInfo &Out);
13576
13577	/// Retrieve the template argument list(s) that should be used to
13578	/// instantiate the definition of the given declaration.
13579	///
13580	/// \param ND the declaration for which we are computing template
13581	/// instantiation arguments.
13582	///
13583	/// \param DC In the event we don't HAVE a declaration yet, we instead provide
13584	/// the decl context where it will be created. In this case, the `Innermost`
13585	/// should likely be provided. If ND is non-null, this is ignored.
13586	///
13587	/// \param Innermost if non-NULL, specifies a template argument list for the
13588	/// template declaration passed as ND.
13589	///
13590	/// \param RelativeToPrimary true if we should get the template
13591	/// arguments relative to the primary template, even when we're
13592	/// dealing with a specialization. This is only relevant for function
13593	/// template specializations.
13594	///
13595	/// \param Pattern If non-NULL, indicates the pattern from which we will be
13596	/// instantiating the definition of the given declaration, \p ND. This is
13597	/// used to determine the proper set of template instantiation arguments for
13598	/// friend function template specializations.
13599	///
13600	/// \param ForConstraintInstantiation when collecting arguments,
13601	/// ForConstraintInstantiation indicates we should continue looking when
13602	/// encountering a lambda generic call operator, and continue looking for
13603	/// arguments on an enclosing class template.
13604	///
13605	/// \param SkipForSpecialization when specified, any template specializations
13606	/// in a traversal would be ignored.
13607	///
13608	/// \param ForDefaultArgumentSubstitution indicates we should continue looking
13609	/// when encountering a specialized member function template, rather than
13610	/// returning immediately.
13611	MultiLevelTemplateArgumentList getTemplateInstantiationArgs(
13612	const NamedDecl D, const* DeclContext DC = nullptr, bool* Final = false,
13613	std::optional<ArrayRef<TemplateArgument>> Innermost = std::nullopt,
13614	bool RelativeToPrimary = false, const FunctionDecl Pattern = nullptr*,
13615	bool ForConstraintInstantiation = false,
13616	bool SkipForSpecialization = false,
13617	bool ForDefaultArgumentSubstitution = false);
13618
13619	/// RAII object to handle the state changes required to synthesize
13620	/// a function body.
13621	class SynthesizedFunctionScope {
13622	Sema &S;
13623	Sema::ContextRAII SavedContext;
13624	bool PushedCodeSynthesisContext = false;
13625
13626	public:
13627	SynthesizedFunctionScope(Sema &S, DeclContext *DC)
13628	: S(S), SavedContext (S, DC) {
13629	auto *FD = dyn_cast<FunctionDecl>(Val: DC);
13630	S.PushFunctionScope();
13631	S.PushExpressionEvaluationContextForFunction(
13632	NewContext: ExpressionEvaluationContext::PotentiallyEvaluated, FD);
13633	if (FD)
13634	FD->setWillHaveBody(true);
13635	else
13636	assert(isa<ObjCMethodDecl>(DC));
13637	}
13638
13639	void addContextNote(SourceLocation UseLoc) {
13640	assert(!PushedCodeSynthesisContext);
13641
13642	Sema::CodeSynthesisContext Ctx;
13643	Ctx.Kind = Sema::CodeSynthesisContext::DefiningSynthesizedFunction;
13644	Ctx.PointOfInstantiation = UseLoc;
13645	Ctx.Entity = cast<Decl>(Val: S.CurContext);
13646	S.pushCodeSynthesisContext(Ctx);
13647
13648	PushedCodeSynthesisContext = true;
13649	}
13650
13651	~SynthesizedFunctionScope() {
13652	if (PushedCodeSynthesisContext)
13653	S.popCodeSynthesisContext();
13654	if (auto *FD = dyn_cast<FunctionDecl>(Val: S.CurContext)) {
13655	FD->setWillHaveBody(false);
13656	S.CheckImmediateEscalatingFunctionDefinition(FD, FSI: S.getCurFunction());
13657	}
13658	S.PopExpressionEvaluationContext();
13659	S.PopFunctionScopeInfo();
13660	}
13661
13662	SynthesizedFunctionScope(const SynthesizedFunctionScope &) = delete;
13663	SynthesizedFunctionScope &
13664	operator=(const SynthesizedFunctionScope &) = delete;
13665	};
13666
13667	/// RAII object to ensure that a code synthesis context is popped on scope
13668	/// exit.
13669	class ScopedCodeSynthesisContext {
13670	Sema &S;
13671
13672	public:
13673	ScopedCodeSynthesisContext(Sema &S, const CodeSynthesisContext &Ctx)
13674	: S(S) {
13675	S.pushCodeSynthesisContext(Ctx);
13676	}
13677
13678	~ScopedCodeSynthesisContext() { S.popCodeSynthesisContext(); }
13679	};
13680
13681	/// List of active code synthesis contexts.
13682	///
13683	/// This vector is treated as a stack. As synthesis of one entity requires
13684	/// synthesis of another, additional contexts are pushed onto the stack.
13685	SmallVector<CodeSynthesisContext, `16`> CodeSynthesisContexts;
13686
13687	/// Specializations whose definitions are currently being instantiated.
13688	llvm::DenseSet<InstantiatingSpecializationsKey> InstantiatingSpecializations;
13689
13690	/// Non-dependent types used in templates that have already been instantiated
13691	/// by some template instantiation.
13692	llvm::DenseSet<QualType> InstantiatedNonDependentTypes;
13693
13694	/// Extra modules inspected when performing a lookup during a template
13695	/// instantiation. Computed lazily.
13696	SmallVector<Module *, `16`> CodeSynthesisContextLookupModules;
13697
13698	/// Cache of additional modules that should be used for name lookup
13699	/// within the current template instantiation. Computed lazily; use
13700	/// getLookupModules() to get a complete set.
13701	llvm::DenseSet<Module *> LookupModulesCache;
13702
13703	/// Map from the most recent declaration of a namespace to the most
13704	/// recent visible declaration of that namespace.
13705	llvm::DenseMap<NamedDecl , NamedDecl > VisibleNamespaceCache;
13706
13707	SFINAETrap CurrentSFINAEContext = nullptr*;
13708
13709	/// The number of \p CodeSynthesisContexts that are not template
13710	/// instantiations and, therefore, should not be counted as part of the
13711	/// instantiation depth.
13712	///
13713	/// When the instantiation depth reaches the user-configurable limit
13714	/// \p LangOptions::InstantiationDepth we will abort instantiation.
13715	// FIXME: Should we have a similar limit for other forms of synthesis?
13716	unsigned NonInstantiationEntries;
13717
13718	/// The depth of the context stack at the point when the most recent
13719	/// error or warning was produced.
13720	///
13721	/// This value is used to suppress printing of redundant context stacks
13722	/// when there are multiple errors or warnings in the same instantiation.
13723	// FIXME: Does this belong in Sema? It's tough to implement it anywhere else.
13724	unsigned LastEmittedCodeSynthesisContextDepth = `0`;
13725
13726	/// The template instantiation callbacks to trace or track
13727	/// instantiations (objects can be chained).
13728	///
13729	/// This callbacks is used to print, trace or track template
13730	/// instantiations as they are being constructed.
13731	std::vector<std::unique_ptr<TemplateInstantiationCallback>>
13732	TemplateInstCallbacks;
13733
13734	/// The current index into pack expansion arguments that will be
13735	/// used for substitution of parameter packs.
13736	///
13737	/// The pack expansion index will be none to indicate that parameter packs
13738	/// should be instantiated as themselves. Otherwise, the index specifies
13739	/// which argument within the parameter pack will be used for substitution.
13740	UnsignedOrNone ArgPackSubstIndex;
13741
13742	/// RAII object used to change the argument pack substitution index
13743	/// within a \c Sema object.
13744	///
13745	/// See \c ArgPackSubstIndex for more information.
13746	class ArgPackSubstIndexRAII {
13747	Sema &Self;
13748	UnsignedOrNone OldSubstIndex;
13749
13750	public:
13751	ArgPackSubstIndexRAII(Sema &Self, UnsignedOrNone NewSubstIndex)
13752	: Self(Self),
13753	OldSubstIndex(std::exchange(obj&: Self.ArgPackSubstIndex, new_val&: NewSubstIndex)) {}
13754
13755	~ArgPackSubstIndexRAII() { Self.ArgPackSubstIndex = OldSubstIndex; }
13756	ArgPackSubstIndexRAII(const ArgPackSubstIndexRAII &) = delete;
13757	ArgPackSubstIndexRAII &operator=(const ArgPackSubstIndexRAII &) = delete;
13758	};
13759
13760	bool pushCodeSynthesisContext(CodeSynthesisContext Ctx);
13761	void popCodeSynthesisContext();
13762
13763	void PrintContextStack(InstantiationContextDiagFuncRef DiagFunc) {
13764	if (!CodeSynthesisContexts.empty() &&
13765	CodeSynthesisContexts.size() != LastEmittedCodeSynthesisContextDepth) {
13766	PrintInstantiationStack(DiagFunc);
13767	LastEmittedCodeSynthesisContextDepth = CodeSynthesisContexts.size();
13768	}
13769	if (PragmaAttributeCurrentTargetDecl)
13770	PrintPragmaAttributeInstantiationPoint(DiagFunc);
13771	}
13772	void PrintContextStack() { PrintContextStack(DiagFunc: getDefaultDiagFunc()); }
13773	/// Prints the current instantiation stack through a series of
13774	/// notes.
13775	void PrintInstantiationStack(InstantiationContextDiagFuncRef DiagFunc);
13776	void PrintInstantiationStack() {
13777	PrintInstantiationStack(DiagFunc: getDefaultDiagFunc());
13778	}
13779
13780	/// Returns a pointer to the current SFINAE context, if any.
13781	[[nodiscard]] SFINAETrap getSFINAEContext() const* {
13782	return CurrentSFINAEContext;
13783	}
13784	[[nodiscard]] bool isSFINAEContext() const {
13785	return CurrentSFINAEContext != nullptr;
13786	}
13787
13788	/// Perform substitution on the type T with a given set of template
13789	/// arguments.
13790	///
13791	/// This routine substitutes the given template arguments into the
13792	/// type T and produces the instantiated type.
13793	///
13794	/// \param T the type into which the template arguments will be
13795	/// substituted. If this type is not dependent, it will be returned
13796	/// immediately.
13797	///
13798	/// \param Args the template arguments that will be
13799	/// substituted for the top-level template parameters within T.
13800	///
13801	/// \param Loc the location in the source code where this substitution
13802	/// is being performed. It will typically be the location of the
13803	/// declarator (if we're instantiating the type of some declaration)
13804	/// or the location of the type in the source code (if, e.g., we're
13805	/// instantiating the type of a cast expression).
13806	///
13807	/// \param Entity the name of the entity associated with a declaration
13808	/// being instantiated (if any). May be empty to indicate that there
13809	/// is no such entity (if, e.g., this is a type that occurs as part of
13810	/// a cast expression) or that the entity has no name (e.g., an
13811	/// unnamed function parameter).
13812	///
13813	/// \param AllowDeducedTST Whether a DeducedTemplateSpecializationType is
13814	/// acceptable as the top level type of the result.
13815	///
13816	/// \param IsIncompleteSubstitution If provided, the pointee will be set
13817	/// whenever substitution would perform a replacement with a null or
13818	/// non-existent template argument.
13819	///
13820	/// \returns If the instantiation succeeds, the instantiated
13821	/// type. Otherwise, produces diagnostics and returns a NULL type.
13822	TypeSourceInfo SubstType(TypeSourceInfo T,
13823	const MultiLevelTemplateArgumentList &TemplateArgs,
13824	SourceLocation Loc, DeclarationName Entity,
13825	bool AllowDeducedTST = false);
13826
13827	QualType SubstType(QualType T,
13828	const MultiLevelTemplateArgumentList &TemplateArgs,
13829	SourceLocation Loc, DeclarationName Entity,
13830	bool IsIncompleteSubstitution = nullptr*);
13831
13832	TypeSourceInfo *SubstType(TypeLoc TL,
13833	const MultiLevelTemplateArgumentList &TemplateArgs,
13834	SourceLocation Loc, DeclarationName Entity);
13835
13836	/// A form of SubstType intended specifically for instantiating the
13837	/// type of a FunctionDecl. Its purpose is solely to force the
13838	/// instantiation of default-argument expressions and to avoid
13839	/// instantiating an exception-specification.
13840	TypeSourceInfo *SubstFunctionDeclType(
13841	TypeSourceInfo T, const* MultiLevelTemplateArgumentList &TemplateArgs,
13842	SourceLocation Loc, DeclarationName Entity, CXXRecordDecl *ThisContext,
13843	Qualifiers ThisTypeQuals, bool EvaluateConstraints = true);
13844	void SubstExceptionSpec(FunctionDecl New, const* FunctionProtoType *Proto,
13845	const MultiLevelTemplateArgumentList &Args);
13846	bool SubstExceptionSpec(SourceLocation Loc,
13847	FunctionProtoType::ExceptionSpecInfo &ESI,
13848	SmallVectorImpl<QualType> &ExceptionStorage,
13849	const MultiLevelTemplateArgumentList &Args);
13850	ParmVarDecl *
13851	SubstParmVarDecl(ParmVarDecl *D,
13852	const MultiLevelTemplateArgumentList &TemplateArgs,
13853	int indexAdjustment, UnsignedOrNone NumExpansions,
13854	bool ExpectParameterPack, bool EvaluateConstraints = true);
13855
13856	/// Substitute the given template arguments into the given set of
13857	/// parameters, producing the set of parameter types that would be generated
13858	/// from such a substitution.
13859	bool SubstParmTypes(SourceLocation Loc, ArrayRef<ParmVarDecl *> Params,
13860	const FunctionProtoType::ExtParameterInfo *ExtParamInfos,
13861	const MultiLevelTemplateArgumentList &TemplateArgs,
13862	SmallVectorImpl<QualType> &ParamTypes,
13863	SmallVectorImpl<ParmVarDecl > OutParams,
13864	ExtParameterInfoBuilder &ParamInfos);
13865
13866	/// Substitute the given template arguments into the default argument.
13867	bool SubstDefaultArgument(SourceLocation Loc, ParmVarDecl *Param,
13868	const MultiLevelTemplateArgumentList &TemplateArgs,
13869	bool ForCallExpr = false);
13870	ExprResult SubstExpr(Expr *E,
13871	const MultiLevelTemplateArgumentList &TemplateArgs);
13872	/// Substitute an expression as if it is a address-of-operand, which makes it
13873	/// act like a CXXIdExpression rather than an attempt to call.
13874	ExprResult SubstCXXIdExpr(Expr *E,
13875	const MultiLevelTemplateArgumentList &TemplateArgs);
13876
13877	// A RAII type used by the TemplateDeclInstantiator and TemplateInstantiator
13878	// to disable constraint evaluation, then restore the state.
13879	template <typename InstTy> struct ConstraintEvalRAII {
13880	InstTy &TI;
13881	bool OldValue;
13882
13883	ConstraintEvalRAII(InstTy &TI)
13884	: TI(TI), OldValue(TI.getEvaluateConstraints()) {
13885	TI.setEvaluateConstraints(false);
13886	}
13887	~ConstraintEvalRAII() { TI.setEvaluateConstraints(OldValue); }
13888	ConstraintEvalRAII(const ConstraintEvalRAII &) = delete;
13889	ConstraintEvalRAII &operator=(const ConstraintEvalRAII &) = delete;
13890	};
13891
13892	// Must be used instead of SubstExpr at 'constraint checking' time.
13893	ExprResult
13894	SubstConstraintExpr(Expr *E,
13895	const MultiLevelTemplateArgumentList &TemplateArgs);
13896	// Unlike the above, this does not evaluate constraints.
13897	ExprResult SubstConstraintExprWithoutSatisfaction(
13898	Expr E, const* MultiLevelTemplateArgumentList &TemplateArgs);
13899
13900	/// Substitute the given template arguments into a list of
13901	/// expressions, expanding pack expansions if required.
13902	///
13903	/// \param Exprs The list of expressions to substitute into.
13904	///
13905	/// \param IsCall Whether this is some form of call, in which case
13906	/// default arguments will be dropped.
13907	///
13908	/// \param TemplateArgs The set of template arguments to substitute.
13909	///
13910	/// \param Outputs Will receive all of the substituted arguments.
13911	///
13912	/// \returns true if an error occurred, false otherwise.
13913	bool SubstExprs(ArrayRef<Expr > Exprs, bool* IsCall,
13914	const MultiLevelTemplateArgumentList &TemplateArgs,
13915	SmallVectorImpl<Expr *> &Outputs);
13916
13917	StmtResult SubstStmt(Stmt *S,
13918	const MultiLevelTemplateArgumentList &TemplateArgs);
13919
13920	ExprResult
13921	SubstInitializer(Expr E, const* MultiLevelTemplateArgumentList &TemplateArgs,
13922	bool CXXDirectInit);
13923
13924	/// Perform substitution on the base class specifiers of the
13925	/// given class template specialization.
13926	///
13927	/// Produces a diagnostic and returns true on error, returns false and
13928	/// attaches the instantiated base classes to the class template
13929	/// specialization if successful.
13930	bool SubstBaseSpecifiers(CXXRecordDecl Instantiation, CXXRecordDecl Pattern,
13931	const MultiLevelTemplateArgumentList &TemplateArgs);
13932
13933	/// Instantiate the definition of a class from a given pattern.
13934	///
13935	/// \param PointOfInstantiation The point of instantiation within the
13936	/// source code.
13937	///
13938	/// \param Instantiation is the declaration whose definition is being
13939	/// instantiated. This will be either a class template specialization
13940	/// or a member class of a class template specialization.
13941	///
13942	/// \param Pattern is the pattern from which the instantiation
13943	/// occurs. This will be either the declaration of a class template or
13944	/// the declaration of a member class of a class template.
13945	///
13946	/// \param TemplateArgs The template arguments to be substituted into
13947	/// the pattern.
13948	///
13949	/// \param TSK the kind of implicit or explicit instantiation to perform.
13950	///
13951	/// \param Complain whether to complain if the class cannot be instantiated
13952	/// due to the lack of a definition.
13953	///
13954	/// \returns true if an error occurred, false otherwise.
13955	bool InstantiateClass(SourceLocation PointOfInstantiation,
13956	CXXRecordDecl Instantiation, CXXRecordDecl Pattern,
13957	const MultiLevelTemplateArgumentList &TemplateArgs,
13958	TemplateSpecializationKind TSK, bool Complain = true);
13959
13960	private:
13961	bool InstantiateClassImpl(SourceLocation PointOfInstantiation,
13962	CXXRecordDecl *Instantiation,
13963	CXXRecordDecl *Pattern,
13964	const MultiLevelTemplateArgumentList &TemplateArgs,
13965	TemplateSpecializationKind TSK, bool Complain);
13966
13967	public:
13968	/// Instantiate the definition of an enum from a given pattern.
13969	///
13970	/// \param PointOfInstantiation The point of instantiation within the
13971	/// source code.
13972	/// \param Instantiation is the declaration whose definition is being
13973	/// instantiated. This will be a member enumeration of a class
13974	/// temploid specialization, or a local enumeration within a
13975	/// function temploid specialization.
13976	/// \param Pattern The templated declaration from which the instantiation
13977	/// occurs.
13978	/// \param TemplateArgs The template arguments to be substituted into
13979	/// the pattern.
13980	/// \param TSK The kind of implicit or explicit instantiation to perform.
13981	///
13982	/// \return \c true if an error occurred, \c false otherwise.
13983	bool InstantiateEnum(SourceLocation PointOfInstantiation,
13984	EnumDecl Instantiation, EnumDecl Pattern,
13985	const MultiLevelTemplateArgumentList &TemplateArgs,
13986	TemplateSpecializationKind TSK);
13987
13988	/// Instantiate the definition of a field from the given pattern.
13989	///
13990	/// \param PointOfInstantiation The point of instantiation within the
13991	/// source code.
13992	/// \param Instantiation is the declaration whose definition is being
13993	/// instantiated. This will be a class of a class temploid
13994	/// specialization, or a local enumeration within a function temploid
13995	/// specialization.
13996	/// \param Pattern The templated declaration from which the instantiation
13997	/// occurs.
13998	/// \param TemplateArgs The template arguments to be substituted into
13999	/// the pattern.
14000	///
14001	/// \return \c true if an error occurred, \c false otherwise.
14002	bool InstantiateInClassInitializer(
14003	SourceLocation PointOfInstantiation, FieldDecl *Instantiation,
14004	FieldDecl Pattern, const* MultiLevelTemplateArgumentList &TemplateArgs);
14005
14006	bool usesPartialOrExplicitSpecialization(
14007	SourceLocation Loc, ClassTemplateSpecializationDecl *ClassTemplateSpec);
14008
14009	bool InstantiateClassTemplateSpecialization(
14010	SourceLocation PointOfInstantiation,
14011	ClassTemplateSpecializationDecl *ClassTemplateSpec,
14012	TemplateSpecializationKind TSK, bool Complain,
14013	bool PrimaryStrictPackMatch);
14014
14015	/// Instantiates the definitions of all of the member
14016	/// of the given class, which is an instantiation of a class template
14017	/// or a member class of a template.
14018	void
14019	InstantiateClassMembers(SourceLocation PointOfInstantiation,
14020	CXXRecordDecl *Instantiation,
14021	const MultiLevelTemplateArgumentList &TemplateArgs,
14022	TemplateSpecializationKind TSK);
14023
14024	/// Instantiate the definitions of all of the members of the
14025	/// given class template specialization, which was named as part of an
14026	/// explicit instantiation.
14027	void InstantiateClassTemplateSpecializationMembers(
14028	SourceLocation PointOfInstantiation,
14029	ClassTemplateSpecializationDecl *ClassTemplateSpec,
14030	TemplateSpecializationKind TSK);
14031
14032	NestedNameSpecifierLoc SubstNestedNameSpecifierLoc(
14033	NestedNameSpecifierLoc NNS,
14034	const MultiLevelTemplateArgumentList &TemplateArgs);
14035
14036	/// Do template substitution on declaration name info.
14037	DeclarationNameInfo
14038	SubstDeclarationNameInfo(const DeclarationNameInfo &NameInfo,
14039	const MultiLevelTemplateArgumentList &TemplateArgs);
14040	TemplateName
14041	SubstTemplateName(SourceLocation TemplateKWLoc,
14042	NestedNameSpecifierLoc &QualifierLoc, TemplateName Name,
14043	SourceLocation NameLoc,
14044	const MultiLevelTemplateArgumentList &TemplateArgs);
14045
14046	bool SubstTypeConstraint(TemplateTypeParmDecl Inst, const* TypeConstraint *TC,
14047	const MultiLevelTemplateArgumentList &TemplateArgs,
14048	bool EvaluateConstraint);
14049
14050	/// Determine whether we are currently performing template instantiation.
14051	bool inTemplateInstantiation() const {
14052	return CodeSynthesisContexts.size() > NonInstantiationEntries;
14053	}
14054
14055	/// Determine whether we are currently performing constraint substitution.
14056	bool inConstraintSubstitution() const {
14057	return !CodeSynthesisContexts.empty() &&
14058	CodeSynthesisContexts.back().InConstraintSubstitution;
14059	}
14060
14061	bool inParameterMappingSubstitution() const {
14062	return !CodeSynthesisContexts.empty() &&
14063	CodeSynthesisContexts.back().InParameterMappingSubstitution &&
14064	!inConstraintSubstitution();
14065	}
14066
14067	using EntityPrinter = llvm::function_ref<void(llvm::raw_ostream &)>;
14068
14069	/// \brief create a Requirement::SubstitutionDiagnostic with only a
14070	/// SubstitutedEntity and DiagLoc using ASTContext's allocator.
14071	concepts::Requirement::SubstitutionDiagnostic *
14072	createSubstDiagAt(SourceLocation Location, EntityPrinter Printer);
14073
14074	///@}
14075
14076	//
14077	//
14078	// -------------------------------------------------------------------------
14079	//
14080	//
14081
14082	/// \name C++ Template Declaration Instantiation
14083	/// Implementations are in SemaTemplateInstantiateDecl.cpp
14084	///@{
14085
14086	public:
14087	/// An entity for which implicit template instantiation is required.
14088	///
14089	/// The source location associated with the declaration is the first place in
14090	/// the source code where the declaration was "used". It is not necessarily
14091	/// the point of instantiation (which will be either before or after the
14092	/// namespace-scope declaration that triggered this implicit instantiation),
14093	/// However, it is the location that diagnostics should generally refer to,
14094	/// because users will need to know what code triggered the instantiation.
14095	typedef std::pair<ValueDecl *, SourceLocation> PendingImplicitInstantiation;
14096
14097	/// The queue of implicit template instantiations that are required
14098	/// but have not yet been performed.
14099	std::deque<PendingImplicitInstantiation> PendingInstantiations;
14100
14101	/// Queue of implicit template instantiations that cannot be performed
14102	/// eagerly.
14103	SmallVector<PendingImplicitInstantiation, `1`> LateParsedInstantiations;
14104
14105	SmallVector<SmallVector<VTableUse, `16`>, `8`> SavedVTableUses;
14106	SmallVector<std::deque<PendingImplicitInstantiation>, `8`>
14107	SavedPendingInstantiations;
14108
14109	/// The queue of implicit template instantiations that are required
14110	/// and must be performed within the current local scope.
14111	///
14112	/// This queue is only used for member functions of local classes in
14113	/// templates, which must be instantiated in the same scope as their
14114	/// enclosing function, so that they can reference function-local
14115	/// types, static variables, enumerators, etc.
14116	std::deque<PendingImplicitInstantiation> PendingLocalImplicitInstantiations;
14117
14118	class LocalEagerInstantiationScope {
14119	public:
14120	LocalEagerInstantiationScope(Sema &S, bool AtEndOfTU)
14121	: S(S), AtEndOfTU(AtEndOfTU) {
14122	SavedPendingLocalImplicitInstantiations.swap(
14123	x&: S.PendingLocalImplicitInstantiations);
14124	}
14125
14126	void perform() {
14127	S.PerformPendingInstantiations(/LocalOnly=/LocalOnly: true,
14128	/AtEndOfTU=/AtEndOfTU);
14129	}
14130
14131	~LocalEagerInstantiationScope() {
14132	assert(S.PendingLocalImplicitInstantiations.empty() &&
14133	"there shouldn't be any pending local implicit instantiations");
14134	SavedPendingLocalImplicitInstantiations.swap(
14135	x&: S.PendingLocalImplicitInstantiations);
14136	}
14137
14138	LocalEagerInstantiationScope(const LocalEagerInstantiationScope &) = delete;
14139	LocalEagerInstantiationScope &
14140	operator=(const LocalEagerInstantiationScope &) = delete;
14141
14142	private:
14143	Sema &S;
14144	bool AtEndOfTU;
14145	std::deque<PendingImplicitInstantiation>
14146	SavedPendingLocalImplicitInstantiations;
14147	};
14148
14149	/// Records and restores the CurFPFeatures state on entry/exit of compound
14150	/// statements.
14151	class FPFeaturesStateRAII {
14152	public:
14153	FPFeaturesStateRAII(Sema &S);
14154	~FPFeaturesStateRAII();
14155	FPOptionsOverride getOverrides() { return OldOverrides; }
14156
14157	private:
14158	Sema &S;
14159	FPOptions OldFPFeaturesState;
14160	FPOptionsOverride OldOverrides;
14161	LangOptions::FPEvalMethodKind OldEvalMethod;
14162	SourceLocation OldFPPragmaLocation;
14163	};
14164
14165	class GlobalEagerInstantiationScope {
14166	public:
14167	GlobalEagerInstantiationScope(Sema &S, bool Enabled, bool AtEndOfTU)
14168	: S(S), Enabled(Enabled), AtEndOfTU(AtEndOfTU) {
14169	if (!Enabled)
14170	return;
14171
14172	S.SavedPendingInstantiations.emplace_back();
14173	S.SavedPendingInstantiations.back().swap(x&: S.PendingInstantiations);
14174
14175	S.SavedVTableUses.emplace_back();
14176	S.SavedVTableUses.back().swap(RHS&: S.VTableUses);
14177	}
14178
14179	void perform() {
14180	if (Enabled) {
14181	S.DefineUsedVTables();
14182	S.PerformPendingInstantiations(/LocalOnly=/LocalOnly: false,
14183	/AtEndOfTU=/AtEndOfTU);
14184	}
14185	}
14186
14187	~GlobalEagerInstantiationScope() {
14188	if (!Enabled)
14189	return;
14190
14191	// Restore the set of pending vtables.
14192	assert(S.VTableUses.empty() &&
14193	"VTableUses should be empty before it is discarded.");
14194	S.VTableUses.swap(RHS&: S.SavedVTableUses.back());
14195	S.SavedVTableUses.pop_back();
14196
14197	// Restore the set of pending implicit instantiations.
14198	if ((S.TUKind != TU_Prefix \|\| !S.LangOpts.PCHInstantiateTemplates) &&
14199	AtEndOfTU) {
14200	assert(S.PendingInstantiations.empty() &&
14201	"PendingInstantiations should be empty before it is discarded.");
14202	S.PendingInstantiations.swap(x&: S.SavedPendingInstantiations.back());
14203	S.SavedPendingInstantiations.pop_back();
14204	} else {
14205	// Template instantiations in the PCH may be delayed until the TU.
14206	S.PendingInstantiations.swap(x&: S.SavedPendingInstantiations.back());
14207	S.PendingInstantiations.insert(
14208	position: S.PendingInstantiations.end(),
14209	first: S.SavedPendingInstantiations.back().begin(),
14210	last: S.SavedPendingInstantiations.back().end());
14211	S.SavedPendingInstantiations.pop_back();
14212	}
14213	}
14214
14215	GlobalEagerInstantiationScope(const GlobalEagerInstantiationScope &) =
14216	delete;
14217	GlobalEagerInstantiationScope &
14218	operator=(const GlobalEagerInstantiationScope &) = delete;
14219
14220	private:
14221	Sema &S;
14222	bool Enabled;
14223	bool AtEndOfTU;
14224	};
14225
14226	ExplicitSpecifier instantiateExplicitSpecifier(
14227	const MultiLevelTemplateArgumentList &TemplateArgs, ExplicitSpecifier ES);
14228
14229	struct LateInstantiatedAttribute {
14230	const Attr *TmplAttr;
14231	LocalInstantiationScope *Scope;
14232	Decl *NewDecl;
14233
14234	LateInstantiatedAttribute(const Attr A, LocalInstantiationScope S,
14235	Decl *D)
14236	: TmplAttr(A), Scope(S), NewDecl(D) {}
14237	};
14238	typedef SmallVector<LateInstantiatedAttribute, `1`> LateInstantiatedAttrVec;
14239
14240	void InstantiateAttrs(const MultiLevelTemplateArgumentList &TemplateArgs,
14241	const Decl Pattern, Decl Inst,
14242	LateInstantiatedAttrVec LateAttrs = nullptr*,
14243	LocalInstantiationScope OuterMostScope = nullptr*);
14244
14245	/// Update instantiation attributes after template was late parsed.
14246	///
14247	/// Some attributes are evaluated based on the body of template. If it is
14248	/// late parsed, such attributes cannot be evaluated when declaration is
14249	/// instantiated. This function is used to update instantiation attributes
14250	/// when template definition is ready.
14251	void updateAttrsForLateParsedTemplate(const Decl Pattern, Decl Inst);
14252
14253	void
14254	InstantiateAttrsForDecl(const MultiLevelTemplateArgumentList &TemplateArgs,
14255	const Decl Pattern, Decl Inst,
14256	LateInstantiatedAttrVec LateAttrs = nullptr*,
14257	LocalInstantiationScope OuterMostScope = nullptr*);
14258
14259	/// In the MS ABI, we need to instantiate default arguments of dllexported
14260	/// default constructors along with the constructor definition. This allows IR
14261	/// gen to emit a constructor closure which calls the default constructor with
14262	/// its default arguments.
14263	void InstantiateDefaultCtorDefaultArgs(CXXConstructorDecl *Ctor);
14264
14265	bool InstantiateDefaultArgument(SourceLocation CallLoc, FunctionDecl *FD,
14266	ParmVarDecl *Param);
14267	void InstantiateExceptionSpec(SourceLocation PointOfInstantiation,
14268	FunctionDecl *Function);
14269
14270	/// Instantiate (or find existing instantiation of) a function template with a
14271	/// given set of template arguments.
14272	///
14273	/// Usually this should not be used, and template argument deduction should be
14274	/// used in its place.
14275	FunctionDecl *InstantiateFunctionDeclaration(
14276	FunctionTemplateDecl FTD, const* TemplateArgumentList *Args,
14277	SourceLocation Loc,
14278	CodeSynthesisContext::SynthesisKind CSC =
14279	CodeSynthesisContext::ExplicitTemplateArgumentSubstitution);
14280
14281	/// Instantiate the definition of the given function from its
14282	/// template.
14283	///
14284	/// \param PointOfInstantiation the point at which the instantiation was
14285	/// required. Note that this is not precisely a "point of instantiation"
14286	/// for the function, but it's close.
14287	///
14288	/// \param Function the already-instantiated declaration of a
14289	/// function template specialization or member function of a class template
14290	/// specialization.
14291	///
14292	/// \param Recursive if true, recursively instantiates any functions that
14293	/// are required by this instantiation.
14294	///
14295	/// \param DefinitionRequired if true, then we are performing an explicit
14296	/// instantiation where the body of the function is required. Complain if
14297	/// there is no such body.
14298	void InstantiateFunctionDefinition(SourceLocation PointOfInstantiation,
14299	FunctionDecl *Function,
14300	bool Recursive = false,
14301	bool DefinitionRequired = false,
14302	bool AtEndOfTU = false);
14303	VarTemplateSpecializationDecl *BuildVarTemplateInstantiation(
14304	VarTemplateDecl VarTemplate, VarDecl FromVar,
14305	const TemplateArgumentList *PartialSpecArgs,
14306	SmallVectorImpl<TemplateArgument> &Converted,
14307	SourceLocation PointOfInstantiation,
14308	LateInstantiatedAttrVec LateAttrs = nullptr*,
14309	LocalInstantiationScope StartingScope = nullptr*);
14310
14311	/// Instantiates a variable template specialization by completing it
14312	/// with appropriate type information and initializer.
14313	VarTemplateSpecializationDecl *CompleteVarTemplateSpecializationDecl(
14314	VarTemplateSpecializationDecl VarSpec, VarDecl PatternDecl,
14315	const MultiLevelTemplateArgumentList &TemplateArgs);
14316
14317	/// BuildVariableInstantiation - Used after a new variable has been created.
14318	/// Sets basic variable data and decides whether to postpone the
14319	/// variable instantiation.
14320	void
14321	BuildVariableInstantiation(VarDecl NewVar, VarDecl OldVar,
14322	const MultiLevelTemplateArgumentList &TemplateArgs,
14323	LateInstantiatedAttrVec *LateAttrs,
14324	DeclContext *Owner,
14325	LocalInstantiationScope *StartingScope,
14326	bool InstantiatingVarTemplate = false,
14327	VarTemplateSpecializationDecl PrevVTSD = nullptr*);
14328
14329	/// Instantiate the initializer of a variable.
14330	void InstantiateVariableInitializer(
14331	VarDecl Var, VarDecl OldVar,
14332	const MultiLevelTemplateArgumentList &TemplateArgs);
14333
14334	/// Instantiate the definition of the given variable from its
14335	/// template.
14336	///
14337	/// \param PointOfInstantiation the point at which the instantiation was
14338	/// required. Note that this is not precisely a "point of instantiation"
14339	/// for the variable, but it's close.
14340	///
14341	/// \param Var the already-instantiated declaration of a templated variable.
14342	///
14343	/// \param Recursive if true, recursively instantiates any functions that
14344	/// are required by this instantiation.
14345	///
14346	/// \param DefinitionRequired if true, then we are performing an explicit
14347	/// instantiation where a definition of the variable is required. Complain
14348	/// if there is no such definition.
14349	void InstantiateVariableDefinition(SourceLocation PointOfInstantiation,
14350	VarDecl Var, bool* Recursive = false,
14351	bool DefinitionRequired = false,
14352	bool AtEndOfTU = false);
14353
14354	void InstantiateMemInitializers(
14355	CXXConstructorDecl New, const* CXXConstructorDecl *Tmpl,
14356	const MultiLevelTemplateArgumentList &TemplateArgs);
14357
14358	/// Find the instantiation of the given declaration within the
14359	/// current instantiation.
14360	///
14361	/// This routine is intended to be used when \p D is a declaration
14362	/// referenced from within a template, that needs to mapped into the
14363	/// corresponding declaration within an instantiation. For example,
14364	/// given:
14365	///
14366	/// \code
14367	/// template<typename T>
14368	/// struct X {
14369	/// enum Kind {
14370	/// KnownValue = sizeof(T)
14371	/// };
14372	///
14373	/// bool getKind() const { return KnownValue; }
14374	/// };
14375	///
14376	/// template struct X<int>;
14377	/// \endcode
14378	///
14379	/// In the instantiation of X<int>::getKind(), we need to map the \p
14380	/// EnumConstantDecl for \p KnownValue (which refers to
14381	/// X<T>::<Kind>::KnownValue) to its instantiation
14382	/// (X<int>::<Kind>::KnownValue).
14383	/// \p FindInstantiatedDecl performs this mapping from within the
14384	/// instantiation of X<int>.
14385	NamedDecl *
14386	FindInstantiatedDecl(SourceLocation Loc, NamedDecl *D,
14387	const MultiLevelTemplateArgumentList &TemplateArgs,
14388	bool FindingInstantiatedContext = false);
14389
14390	/// Finds the instantiation of the given declaration context
14391	/// within the current instantiation.
14392	///
14393	/// \returns NULL if there was an error
14394	DeclContext *
14395	FindInstantiatedContext(SourceLocation Loc, DeclContext *DC,
14396	const MultiLevelTemplateArgumentList &TemplateArgs);
14397
14398	Decl SubstDecl(Decl D, DeclContext *Owner,
14399	const MultiLevelTemplateArgumentList &TemplateArgs);
14400
14401	/// Substitute the name and return type of a defaulted 'operator<=>' to form
14402	/// an implicit 'operator=='.
14403	FunctionDecl SubstSpaceshipAsEqualEqual(CXXRecordDecl RD,
14404	FunctionDecl *Spaceship);
14405
14406	/// Performs template instantiation for all implicit template
14407	/// instantiations we have seen until this point.
14408	void PerformPendingInstantiations(bool LocalOnly = false,
14409	bool AtEndOfTU = true);
14410
14411	TemplateParameterList *
14412	SubstTemplateParams(TemplateParameterList Params, DeclContext Owner,
14413	const MultiLevelTemplateArgumentList &TemplateArgs,
14414	bool EvaluateConstraints = true);
14415
14416	void PerformDependentDiagnostics(
14417	const DeclContext *Pattern,
14418	const MultiLevelTemplateArgumentList &TemplateArgs);
14419
14420	private:
14421	/// Introduce the instantiated local variables into the local
14422	/// instantiation scope.
14423	void addInstantiatedLocalVarsToScope(FunctionDecl *Function,
14424	const FunctionDecl *PatternDecl,
14425	LocalInstantiationScope &Scope);
14426	/// Introduce the instantiated function parameters into the local
14427	/// instantiation scope, and set the parameter names to those used
14428	/// in the template.
14429	bool addInstantiatedParametersToScope(
14430	FunctionDecl Function, const* FunctionDecl *PatternDecl,
14431	LocalInstantiationScope &Scope,
14432	const MultiLevelTemplateArgumentList &TemplateArgs);
14433
14434	/// Introduce the instantiated captures of the lambda into the local
14435	/// instantiation scope.
14436	bool addInstantiatedCapturesToScope(
14437	FunctionDecl Function, const* FunctionDecl *PatternDecl,
14438	LocalInstantiationScope &Scope,
14439	const MultiLevelTemplateArgumentList &TemplateArgs);
14440
14441	int ParsingClassDepth = `0`;
14442
14443	class SavePendingParsedClassStateRAII {
14444	public:
14445	SavePendingParsedClassStateRAII(Sema &S) : S(S) { swapSavedState(); }
14446
14447	~SavePendingParsedClassStateRAII() {
14448	assert(S.DelayedOverridingExceptionSpecChecks.empty() &&
14449	"there shouldn't be any pending delayed exception spec checks");
14450	assert(S.DelayedEquivalentExceptionSpecChecks.empty() &&
14451	"there shouldn't be any pending delayed exception spec checks");
14452	swapSavedState();
14453	}
14454
14455	SavePendingParsedClassStateRAII(const SavePendingParsedClassStateRAII &) =
14456	delete;
14457	SavePendingParsedClassStateRAII &
14458	operator=(const SavePendingParsedClassStateRAII &) = delete;
14459
14460	private:
14461	Sema &S;
14462	decltype(DelayedOverridingExceptionSpecChecks)
14463	SavedOverridingExceptionSpecChecks;
14464	decltype(DelayedEquivalentExceptionSpecChecks)
14465	SavedEquivalentExceptionSpecChecks;
14466
14467	void swapSavedState() {
14468	SavedOverridingExceptionSpecChecks.swap(
14469	RHS&: S.DelayedOverridingExceptionSpecChecks);
14470	SavedEquivalentExceptionSpecChecks.swap(
14471	RHS&: S.DelayedEquivalentExceptionSpecChecks);
14472	}
14473	};
14474
14475	///@}
14476
14477	//
14478	//
14479	// -------------------------------------------------------------------------
14480	//
14481	//
14482
14483	/// \name C++ Variadic Templates
14484	/// Implementations are in SemaTemplateVariadic.cpp
14485	///@{
14486
14487	public:
14488	/// Determine whether an unexpanded parameter pack might be permitted in this
14489	/// location. Useful for error recovery.
14490	bool isUnexpandedParameterPackPermitted();
14491
14492	/// The context in which an unexpanded parameter pack is
14493	/// being diagnosed.
14494	///
14495	/// Note that the values of this enumeration line up with the first
14496	/// argument to the \c err_unexpanded_parameter_pack diagnostic.
14497	enum UnexpandedParameterPackContext {
14498	/// An arbitrary expression.
14499	UPPC_Expression = `0`,
14500
14501	/// The base type of a class type.
14502	UPPC_BaseType,
14503
14504	/// The type of an arbitrary declaration.
14505	UPPC_DeclarationType,
14506
14507	/// The type of a data member.
14508	UPPC_DataMemberType,
14509
14510	/// The size of a bit-field.
14511	UPPC_BitFieldWidth,
14512
14513	/// The expression in a static assertion.
14514	UPPC_StaticAssertExpression,
14515
14516	/// The fixed underlying type of an enumeration.
14517	UPPC_FixedUnderlyingType,
14518
14519	/// The enumerator value.
14520	UPPC_EnumeratorValue,
14521
14522	/// A using declaration.
14523	UPPC_UsingDeclaration,
14524
14525	/// A friend declaration.
14526	UPPC_FriendDeclaration,
14527
14528	/// A declaration qualifier.
14529	UPPC_DeclarationQualifier,
14530
14531	/// An initializer.
14532	UPPC_Initializer,
14533
14534	/// A default argument.
14535	UPPC_DefaultArgument,
14536
14537	/// The type of a non-type template parameter.
14538	UPPC_NonTypeTemplateParameterType,
14539
14540	/// The type of an exception.
14541	UPPC_ExceptionType,
14542
14543	/// Explicit specialization.
14544	UPPC_ExplicitSpecialization,
14545
14546	/// Partial specialization.
14547	UPPC_PartialSpecialization,
14548
14549	/// Microsoft __if_exists.
14550	UPPC_IfExists,
14551
14552	/// Microsoft __if_not_exists.
14553	UPPC_IfNotExists,
14554
14555	/// Lambda expression.
14556	UPPC_Lambda,
14557
14558	/// Block expression.
14559	UPPC_Block,
14560
14561	/// A type constraint.
14562	UPPC_TypeConstraint,
14563
14564	// A requirement in a requires-expression.
14565	UPPC_Requirement,
14566
14567	// A requires-clause.
14568	UPPC_RequiresClause,
14569	};
14570
14571	/// Diagnose unexpanded parameter packs.
14572	///
14573	/// \param Loc The location at which we should emit the diagnostic.
14574	///
14575	/// \param UPPC The context in which we are diagnosing unexpanded
14576	/// parameter packs.
14577	///
14578	/// \param Unexpanded the set of unexpanded parameter packs.
14579	///
14580	/// \returns true if an error occurred, false otherwise.
14581	bool DiagnoseUnexpandedParameterPacks(
14582	SourceLocation Loc, UnexpandedParameterPackContext UPPC,
14583	ArrayRef<UnexpandedParameterPack> Unexpanded);
14584
14585	/// If the given type contains an unexpanded parameter pack,
14586	/// diagnose the error.
14587	///
14588	/// \param Loc The source location where a diagnostc should be emitted.
14589	///
14590	/// \param T The type that is being checked for unexpanded parameter
14591	/// packs.
14592	///
14593	/// \returns true if an error occurred, false otherwise.
14594	bool DiagnoseUnexpandedParameterPack(SourceLocation Loc, TypeSourceInfo *T,
14595	UnexpandedParameterPackContext UPPC);
14596
14597	/// If the given expression contains an unexpanded parameter
14598	/// pack, diagnose the error.
14599	///
14600	/// \param E The expression that is being checked for unexpanded
14601	/// parameter packs.
14602	///
14603	/// \returns true if an error occurred, false otherwise.
14604	bool DiagnoseUnexpandedParameterPack(
14605	Expr *E, UnexpandedParameterPackContext UPPC = UPPC_Expression);
14606
14607	/// If the given requirees-expression contains an unexpanded reference to one
14608	/// of its own parameter packs, diagnose the error.
14609	///
14610	/// \param RE The requiress-expression that is being checked for unexpanded
14611	/// parameter packs.
14612	///
14613	/// \returns true if an error occurred, false otherwise.
14614	bool DiagnoseUnexpandedParameterPackInRequiresExpr(RequiresExpr *RE);
14615
14616	/// If the given nested-name-specifier contains an unexpanded
14617	/// parameter pack, diagnose the error.
14618	///
14619	/// \param SS The nested-name-specifier that is being checked for
14620	/// unexpanded parameter packs.
14621	///
14622	/// \returns true if an error occurred, false otherwise.
14623	bool DiagnoseUnexpandedParameterPack(const CXXScopeSpec &SS,
14624	UnexpandedParameterPackContext UPPC);
14625
14626	/// If the given name contains an unexpanded parameter pack,
14627	/// diagnose the error.
14628	///
14629	/// \param NameInfo The name (with source location information) that
14630	/// is being checked for unexpanded parameter packs.
14631	///
14632	/// \returns true if an error occurred, false otherwise.
14633	bool DiagnoseUnexpandedParameterPack(const DeclarationNameInfo &NameInfo,
14634	UnexpandedParameterPackContext UPPC);
14635
14636	/// If the given template name contains an unexpanded parameter pack,
14637	/// diagnose the error.
14638	///
14639	/// \param Loc The location of the template name.
14640	///
14641	/// \param Template The template name that is being checked for unexpanded
14642	/// parameter packs.
14643	///
14644	/// \returns true if an error occurred, false otherwise.
14645	bool DiagnoseUnexpandedParameterPack(SourceLocation Loc,
14646	TemplateName Template,
14647	UnexpandedParameterPackContext UPPC);
14648
14649	/// If the given template argument contains an unexpanded parameter
14650	/// pack, diagnose the error.
14651	///
14652	/// \param Arg The template argument that is being checked for unexpanded
14653	/// parameter packs.
14654	///
14655	/// \returns true if an error occurred, false otherwise.
14656	bool DiagnoseUnexpandedParameterPack(TemplateArgumentLoc Arg,
14657	UnexpandedParameterPackContext UPPC);
14658
14659	/// Collect the set of unexpanded parameter packs within the given
14660	/// template argument.
14661	///
14662	/// \param Arg The template argument that will be traversed to find
14663	/// unexpanded parameter packs.
14664	void collectUnexpandedParameterPacks(
14665	TemplateArgument Arg,
14666	SmallVectorImpl<UnexpandedParameterPack> &Unexpanded);
14667
14668	/// Collect the set of unexpanded parameter packs within the given
14669	/// template argument.
14670	///
14671	/// \param Arg The template argument that will be traversed to find
14672	/// unexpanded parameter packs.
14673	void collectUnexpandedParameterPacks(
14674	TemplateArgumentLoc Arg,
14675	SmallVectorImpl<UnexpandedParameterPack> &Unexpanded);
14676
14677	/// Collect the set of unexpanded parameter packs within the given
14678	/// type.
14679	///
14680	/// \param T The type that will be traversed to find
14681	/// unexpanded parameter packs.
14682	void collectUnexpandedParameterPacks(
14683	QualType T, SmallVectorImpl<UnexpandedParameterPack> &Unexpanded);
14684
14685	/// Collect the set of unexpanded parameter packs within the given
14686	/// type.
14687	///
14688	/// \param TL The type that will be traversed to find
14689	/// unexpanded parameter packs.
14690	void collectUnexpandedParameterPacks(
14691	TypeLoc TL, SmallVectorImpl<UnexpandedParameterPack> &Unexpanded);
14692
14693	/// Collect the set of unexpanded parameter packs within the given
14694	/// nested-name-specifier.
14695	///
14696	/// \param NNS The nested-name-specifier that will be traversed to find
14697	/// unexpanded parameter packs.
14698	void collectUnexpandedParameterPacks(
14699	NestedNameSpecifierLoc NNS,
14700	SmallVectorImpl<UnexpandedParameterPack> &Unexpanded);
14701
14702	/// Collect the set of unexpanded parameter packs within the given
14703	/// name.
14704	///
14705	/// \param NameInfo The name that will be traversed to find
14706	/// unexpanded parameter packs.
14707	void collectUnexpandedParameterPacks(
14708	const DeclarationNameInfo &NameInfo,
14709	SmallVectorImpl<UnexpandedParameterPack> &Unexpanded);
14710
14711	/// Collect the set of unexpanded parameter packs within the given
14712	/// expression.
14713	static void collectUnexpandedParameterPacks(
14714	Expr *E, SmallVectorImpl<UnexpandedParameterPack> &Unexpanded);
14715
14716	/// Invoked when parsing a template argument.
14717	///
14718	/// \param Arg the template argument, which may already be invalid.
14719	///
14720	/// If it is followed by ellipsis, this function is called before
14721	/// `ActOnPackExpansion`.
14722	ParsedTemplateArgument
14723	ActOnTemplateTemplateArgument(const ParsedTemplateArgument &Arg);
14724
14725	/// Invoked when parsing a template argument followed by an
14726	/// ellipsis, which creates a pack expansion.
14727	///
14728	/// \param Arg The template argument preceding the ellipsis, which
14729	/// may already be invalid.
14730	///
14731	/// \param EllipsisLoc The location of the ellipsis.
14732	ParsedTemplateArgument ActOnPackExpansion(const ParsedTemplateArgument &Arg,
14733	SourceLocation EllipsisLoc);
14734
14735	/// Invoked when parsing a type followed by an ellipsis, which
14736	/// creates a pack expansion.
14737	///
14738	/// \param Type The type preceding the ellipsis, which will become
14739	/// the pattern of the pack expansion.
14740	///
14741	/// \param EllipsisLoc The location of the ellipsis.
14742	TypeResult ActOnPackExpansion(ParsedType Type, SourceLocation EllipsisLoc);
14743
14744	/// Construct a pack expansion type from the pattern of the pack
14745	/// expansion.
14746	TypeSourceInfo CheckPackExpansion(TypeSourceInfo Pattern,
14747	SourceLocation EllipsisLoc,
14748	UnsignedOrNone NumExpansions);
14749
14750	/// Construct a pack expansion type from the pattern of the pack
14751	/// expansion.
14752	QualType CheckPackExpansion(QualType Pattern, SourceRange PatternRange,
14753	SourceLocation EllipsisLoc,
14754	UnsignedOrNone NumExpansions);
14755
14756	/// Invoked when parsing an expression followed by an ellipsis, which
14757	/// creates a pack expansion.
14758	///
14759	/// \param Pattern The expression preceding the ellipsis, which will become
14760	/// the pattern of the pack expansion.
14761	///
14762	/// \param EllipsisLoc The location of the ellipsis.
14763	ExprResult ActOnPackExpansion(Expr *Pattern, SourceLocation EllipsisLoc);
14764
14765	/// Invoked when parsing an expression followed by an ellipsis, which
14766	/// creates a pack expansion.
14767	///
14768	/// \param Pattern The expression preceding the ellipsis, which will become
14769	/// the pattern of the pack expansion.
14770	///
14771	/// \param EllipsisLoc The location of the ellipsis.
14772	ExprResult CheckPackExpansion(Expr *Pattern, SourceLocation EllipsisLoc,
14773	UnsignedOrNone NumExpansions);
14774
14775	/// Determine whether we could expand a pack expansion with the
14776	/// given set of parameter packs into separate arguments by repeatedly
14777	/// transforming the pattern.
14778	///
14779	/// \param EllipsisLoc The location of the ellipsis that identifies the
14780	/// pack expansion.
14781	///
14782	/// \param PatternRange The source range that covers the entire pattern of
14783	/// the pack expansion.
14784	///
14785	/// \param Unexpanded The set of unexpanded parameter packs within the
14786	/// pattern.
14787	///
14788	/// \param ShouldExpand Will be set to \c true if the transformer should
14789	/// expand the corresponding pack expansions into separate arguments. When
14790	/// set, \c NumExpansions must also be set.
14791	///
14792	/// \param RetainExpansion Whether the caller should add an unexpanded
14793	/// pack expansion after all of the expanded arguments. This is used
14794	/// when extending explicitly-specified template argument packs per
14795	/// C++0x [temp.arg.explicit]p9.
14796	///
14797	/// \param NumExpansions The number of separate arguments that will be in
14798	/// the expanded form of the corresponding pack expansion. This is both an
14799	/// input and an output parameter, which can be set by the caller if the
14800	/// number of expansions is known a priori (e.g., due to a prior substitution)
14801	/// and will be set by the callee when the number of expansions is known.
14802	/// The callee must set this value when \c ShouldExpand is \c true; it may
14803	/// set this value in other cases.
14804	///
14805	/// \returns true if an error occurred (e.g., because the parameter packs
14806	/// are to be instantiated with arguments of different lengths), false
14807	/// otherwise. If false, \c ShouldExpand (and possibly \c NumExpansions)
14808	/// must be set.
14809	bool CheckParameterPacksForExpansion(
14810	SourceLocation EllipsisLoc, SourceRange PatternRange,
14811	ArrayRef<UnexpandedParameterPack> Unexpanded,
14812	const MultiLevelTemplateArgumentList &TemplateArgs,
14813	bool FailOnPackProducingTemplates, bool &ShouldExpand,
14814	bool &RetainExpansion, UnsignedOrNone &NumExpansions,
14815	bool Diagnose = true);
14816
14817	/// Determine the number of arguments in the given pack expansion
14818	/// type.
14819	///
14820	/// This routine assumes that the number of arguments in the expansion is
14821	/// consistent across all of the unexpanded parameter packs in its pattern.
14822	///
14823	/// Returns an empty Optional if the type can't be expanded.
14824	UnsignedOrNone getNumArgumentsInExpansion(
14825	QualType T, const MultiLevelTemplateArgumentList &TemplateArgs);
14826
14827	UnsignedOrNone getNumArgumentsInExpansionFromUnexpanded(
14828	llvm::ArrayRef<UnexpandedParameterPack> Unexpanded,
14829	const MultiLevelTemplateArgumentList &TemplateArgs);
14830
14831	/// Determine whether the given declarator contains any unexpanded
14832	/// parameter packs.
14833	///
14834	/// This routine is used by the parser to disambiguate function declarators
14835	/// with an ellipsis prior to the ')', e.g.,
14836	///
14837	/// \code
14838	/// void f(T...);
14839	/// \endcode
14840	///
14841	/// To determine whether we have an (unnamed) function parameter pack or
14842	/// a variadic function.
14843	///
14844	/// \returns true if the declarator contains any unexpanded parameter packs,
14845	/// false otherwise.
14846	bool containsUnexpandedParameterPacks(Declarator &D);
14847
14848	/// Returns the pattern of the pack expansion for a template argument.
14849	///
14850	/// \param OrigLoc The template argument to expand.
14851	///
14852	/// \param Ellipsis Will be set to the location of the ellipsis.
14853	///
14854	/// \param NumExpansions Will be set to the number of expansions that will
14855	/// be generated from this pack expansion, if known a priori.
14856	TemplateArgumentLoc
14857	getTemplateArgumentPackExpansionPattern(TemplateArgumentLoc OrigLoc,
14858	SourceLocation &Ellipsis,
14859	UnsignedOrNone &NumExpansions) const;
14860
14861	/// Given a template argument that contains an unexpanded parameter pack, but
14862	/// which has already been substituted, attempt to determine the number of
14863	/// elements that will be produced once this argument is fully-expanded.
14864	///
14865	/// This is intended for use when transforming 'sizeof...(Arg)' in order to
14866	/// avoid actually expanding the pack where possible.
14867	UnsignedOrNone getFullyPackExpandedSize(TemplateArgument Arg);
14868
14869	/// Called when an expression computing the size of a parameter pack
14870	/// is parsed.
14871	///
14872	/// \code
14873	/// template<typename ...Types> struct count {
14874	/// static const unsigned value = sizeof...(Types);
14875	/// };
14876	/// \endcode
14877	///
14878	//
14879	/// \param OpLoc The location of the "sizeof" keyword.
14880	/// \param Name The name of the parameter pack whose size will be determined.
14881	/// \param NameLoc The source location of the name of the parameter pack.
14882	/// \param RParenLoc The location of the closing parentheses.
14883	ExprResult ActOnSizeofParameterPackExpr(Scope *S, SourceLocation OpLoc,
14884	IdentifierInfo &Name,
14885	SourceLocation NameLoc,
14886	SourceLocation RParenLoc);
14887
14888	ExprResult ActOnPackIndexingExpr(Scope S, Expr PackExpression,
14889	SourceLocation EllipsisLoc,
14890	SourceLocation LSquareLoc, Expr *IndexExpr,
14891	SourceLocation RSquareLoc);
14892
14893	ExprResult BuildPackIndexingExpr(Expr *PackExpression,
14894	SourceLocation EllipsisLoc, Expr *IndexExpr,
14895	SourceLocation RSquareLoc,
14896	ArrayRef<Expr *> ExpandedExprs = {},
14897	bool FullySubstituted = false);
14898
14899	/// Handle a C++1z fold-expression: ( expr op ... op expr ).
14900	ExprResult ActOnCXXFoldExpr(Scope S, SourceLocation LParenLoc, Expr LHS,
14901	tok::TokenKind Operator,
14902	SourceLocation EllipsisLoc, Expr *RHS,
14903	SourceLocation RParenLoc);
14904	ExprResult BuildCXXFoldExpr(UnresolvedLookupExpr *Callee,
14905	SourceLocation LParenLoc, Expr *LHS,
14906	BinaryOperatorKind Operator,
14907	SourceLocation EllipsisLoc, Expr *RHS,
14908	SourceLocation RParenLoc,
14909	UnsignedOrNone NumExpansions);
14910	ExprResult BuildEmptyCXXFoldExpr(SourceLocation EllipsisLoc,
14911	BinaryOperatorKind Operator);
14912
14913	///@}
14914
14915	//
14916	//
14917	// -------------------------------------------------------------------------
14918	//
14919	//
14920
14921	/// \name Constraints and Concepts
14922	/// Implementations are in SemaConcept.cpp
14923	///@{
14924
14925	public:
14926	ExprResult ActOnCXXReflectExpr(SourceLocation OpLoc, TypeSourceInfo *TSI);
14927
14928	ExprResult BuildCXXReflectExpr(SourceLocation OperatorLoc,
14929	TypeSourceInfo *TSI);
14930
14931	public:
14932	void PushSatisfactionStackEntry(const NamedDecl *D,
14933	const llvm::FoldingSetNodeID &ID) {
14934	const NamedDecl *Can = cast<NamedDecl>(Val: D->getCanonicalDecl());
14935	SatisfactionStack.emplace_back(Args&: Can, Args: ID);
14936	}
14937
14938	void PopSatisfactionStackEntry() { SatisfactionStack.pop_back(); }
14939
14940	bool SatisfactionStackContains(const NamedDecl *D,
14941	const llvm::FoldingSetNodeID &ID) const {
14942	const NamedDecl *Can = cast<NamedDecl>(Val: D->getCanonicalDecl());
14943	return llvm::is_contained(Range: SatisfactionStack,
14944	Element: SatisfactionStackEntryTy {Can, ID});
14945	}
14946
14947	using SatisfactionStackEntryTy =
14948	std::pair<const NamedDecl *, llvm::FoldingSetNodeID>;
14949
14950	// Resets the current SatisfactionStack for cases where we are instantiating
14951	// constraints as a 'side effect' of normal instantiation in a way that is not
14952	// indicative of recursive definition.
14953	class SatisfactionStackResetRAII {
14954	llvm::SmallVector<SatisfactionStackEntryTy, `10`> BackupSatisfactionStack;
14955	Sema &SemaRef;
14956
14957	public:
14958	SatisfactionStackResetRAII(Sema &S) : SemaRef(S) {
14959	SemaRef.SwapSatisfactionStack(NewSS&: BackupSatisfactionStack);
14960	}
14961
14962	~SatisfactionStackResetRAII() {
14963	SemaRef.SwapSatisfactionStack(NewSS&: BackupSatisfactionStack);
14964	}
14965
14966	SatisfactionStackResetRAII(const SatisfactionStackResetRAII &) = delete;
14967	SatisfactionStackResetRAII &
14968	operator=(const SatisfactionStackResetRAII &) = delete;
14969	};
14970
14971	void SwapSatisfactionStack(
14972	llvm::SmallVectorImpl<SatisfactionStackEntryTy> &NewSS) {
14973	SatisfactionStack.swap(RHS&: NewSS);
14974	}
14975
14976	using ConstrainedDeclOrNestedRequirement =
14977	llvm::PointerUnion<const NamedDecl *,
14978	const concepts::NestedRequirement *>;
14979
14980	/// Check whether the given expression is a valid constraint expression.
14981	/// A diagnostic is emitted if it is not, false is returned, and
14982	/// PossibleNonPrimary will be set to true if the failure might be due to a
14983	/// non-primary expression being used as an atomic constraint.
14984	bool CheckConstraintExpression(const Expr *CE, Token NextToken = Token (),
14985	bool PossibleNonPrimary = nullptr*,
14986	bool IsTrailingRequiresClause = false);
14987
14988	/// \brief Check whether the given list of constraint expressions are
14989	/// satisfied (as if in a 'conjunction') given template arguments.
14990	/// \param Template the template-like entity that triggered the constraints
14991	/// check (either a concept or a constrained entity).
14992	/// \param ConstraintExprs a list of constraint expressions, treated as if
14993	/// they were 'AND'ed together.
14994	/// \param TemplateArgLists the list of template arguments to substitute into
14995	/// the constraint expression.
14996	/// \param TemplateIDRange The source range of the template id that
14997	/// caused the constraints check.
14998	/// \param Satisfaction if true is returned, will contain details of the
14999	/// satisfaction, with enough information to diagnose an unsatisfied
15000	/// expression.
15001	/// \returns true if an error occurred and satisfaction could not be checked,
15002	/// false otherwise.
15003	bool CheckConstraintSatisfaction(
15004	ConstrainedDeclOrNestedRequirement Entity,
15005	ArrayRef<AssociatedConstraint> AssociatedConstraints,
15006	const MultiLevelTemplateArgumentList &TemplateArgLists,
15007	SourceRange TemplateIDRange, ConstraintSatisfaction &Satisfaction,
15008	const ConceptReference TopLevelConceptId = nullptr*,
15009	Expr ConvertedExpr = nullptr**);
15010
15011	/// Check whether the given function decl's trailing requires clause is
15012	/// satisfied, if any. Returns false and updates Satisfaction with the
15013	/// satisfaction verdict if successful, emits a diagnostic and returns true if
15014	/// an error occurred and satisfaction could not be determined.
15015	///
15016	/// \returns true if an error occurred, false otherwise.
15017	bool CheckFunctionConstraints(const FunctionDecl *FD,
15018	ConstraintSatisfaction &Satisfaction,
15019	SourceLocation UsageLoc = SourceLocation (),
15020	bool ForOverloadResolution = false);
15021
15022	// Calculates whether two constraint expressions are equal irrespective of a
15023	// difference in 'depth'. This takes a pair of optional 'NamedDecl's 'Old' and
15024	// 'New', which are the "source" of the constraint, since this is necessary
15025	// for figuring out the relative 'depth' of the constraint. The depth of the
15026	// 'primary template' and the 'instantiated from' templates aren't necessarily
15027	// the same, such as a case when one is a 'friend' defined in a class.
15028	bool AreConstraintExpressionsEqual(const NamedDecl *Old,
15029	const Expr *OldConstr,
15030	const TemplateCompareNewDeclInfo &New,
15031	const Expr *NewConstr);
15032
15033	// Calculates whether the friend function depends on an enclosing template for
15034	// the purposes of [temp.friend] p9.
15035	bool FriendConstraintsDependOnEnclosingTemplate(const FunctionDecl *FD);
15036
15037	/// \brief Ensure that the given template arguments satisfy the constraints
15038	/// associated with the given template, emitting a diagnostic if they do not.
15039	///
15040	/// \param Template The template to which the template arguments are being
15041	/// provided.
15042	///
15043	/// \param TemplateArgs The converted, canonicalized template arguments.
15044	///
15045	/// \param TemplateIDRange The source range of the template id that
15046	/// caused the constraints check.
15047	///
15048	/// \returns true if the constrains are not satisfied or could not be checked
15049	/// for satisfaction, false if the constraints are satisfied.
15050	bool EnsureTemplateArgumentListConstraints(
15051	TemplateDecl *Template,
15052	const MultiLevelTemplateArgumentList &TemplateArgs,
15053	SourceRange TemplateIDRange);
15054
15055	bool CheckFunctionTemplateConstraints(SourceLocation PointOfInstantiation,
15056	FunctionDecl *Decl,
15057	ArrayRef<TemplateArgument> TemplateArgs,
15058	ConstraintSatisfaction &Satisfaction);
15059
15060	/// \brief Emit diagnostics explaining why a constraint expression was deemed
15061	/// unsatisfied.
15062	/// \param First whether this is the first time an unsatisfied constraint is
15063	/// diagnosed for this error.
15064	void DiagnoseUnsatisfiedConstraint(const ConstraintSatisfaction &Satisfaction,
15065	SourceLocation Loc = {},
15066	bool First = true);
15067
15068	/// \brief Emit diagnostics explaining why a constraint expression was deemed
15069	/// unsatisfied.
15070	void
15071	DiagnoseUnsatisfiedConstraint(const ConceptSpecializationExpr *ConstraintExpr,
15072	bool First = true);
15073
15074	const NormalizedConstraint *getNormalizedAssociatedConstraints(
15075	ConstrainedDeclOrNestedRequirement Entity,
15076	ArrayRef<AssociatedConstraint> AssociatedConstraints);
15077
15078	/// \brief Check whether the given declaration's associated constraints are
15079	/// at least as constrained than another declaration's according to the
15080	/// partial ordering of constraints.
15081	///
15082	/// \param Result If no error occurred, receives the result of true if D1 is
15083	/// at least constrained than D2, and false otherwise.
15084	///
15085	/// \returns true if an error occurred, false otherwise.
15086	bool IsAtLeastAsConstrained(const NamedDecl *D1,
15087	MutableArrayRef<AssociatedConstraint> AC1,
15088	const NamedDecl *D2,
15089	MutableArrayRef<AssociatedConstraint> AC2,
15090	bool &Result);
15091
15092	/// If D1 was not at least as constrained as D2, but would've been if a pair
15093	/// of atomic constraints involved had been declared in a concept and not
15094	/// repeated in two separate places in code.
15095	/// \returns true if such a diagnostic was emitted, false otherwise.
15096	bool MaybeEmitAmbiguousAtomicConstraintsDiagnostic(
15097	const NamedDecl *D1, ArrayRef<AssociatedConstraint> AC1,
15098	const NamedDecl *D2, ArrayRef<AssociatedConstraint> AC2);
15099
15100	/// Cache the satisfaction of an atomic constraint.
15101	/// The key is based on the unsubstituted expression and the parameter
15102	/// mapping. This lets us not substituting the mapping more than once,
15103	/// which is (very!) expensive.
15104	/// FIXME: this should be private.
15105	llvm::DenseMap<llvm::FoldingSetNodeID,
15106	UnsubstitutedConstraintSatisfactionCacheResult>
15107	UnsubstitutedConstraintSatisfactionCache;
15108
15109	private:
15110	/// Caches pairs of template-like decls whose associated constraints were
15111	/// checked for subsumption and whether or not the first's constraints did in
15112	/// fact subsume the second's.
15113	llvm::DenseMap<std::pair<const NamedDecl , const* NamedDecl >, bool*>
15114	SubsumptionCache;
15115	/// Caches the normalized associated constraints of declarations (concepts or
15116	/// constrained declarations). If an error occurred while normalizing the
15117	/// associated constraints of the template or concept, nullptr will be cached
15118	/// here.
15119	llvm::DenseMap<ConstrainedDeclOrNestedRequirement, NormalizedConstraint *>
15120	NormalizationCache;
15121
15122	/// Cache whether the associated constraint of a declaration
15123	/// is satisfied.
15124	llvm::ContextualFoldingSet<ConstraintSatisfaction, const ASTContext &>
15125	SatisfactionCache;
15126
15127	// The current stack of constraint satisfactions, so we can exit-early.
15128	llvm::SmallVector<SatisfactionStackEntryTy, `10`> SatisfactionStack;
15129
15130	/// Used by SetupConstraintCheckingTemplateArgumentsAndScope to set up the
15131	/// LocalInstantiationScope of the current non-lambda function. For lambdas,
15132	/// use LambdaScopeForCallOperatorInstantiationRAII.
15133	bool
15134	SetupConstraintScope(FunctionDecl *FD,
15135	std::optional<ArrayRef<TemplateArgument>> TemplateArgs,
15136	const MultiLevelTemplateArgumentList &MLTAL,
15137	LocalInstantiationScope &Scope);
15138
15139	/// Used during constraint checking, sets up the constraint template argument
15140	/// lists, and calls SetupConstraintScope to set up the
15141	/// LocalInstantiationScope to have the proper set of ParVarDecls configured.
15142	std::optional<MultiLevelTemplateArgumentList>
15143	SetupConstraintCheckingTemplateArgumentsAndScope(
15144	FunctionDecl *FD, std::optional<ArrayRef<TemplateArgument>> TemplateArgs,
15145	LocalInstantiationScope &Scope);
15146
15147	///@}
15148
15149	//
15150	//
15151	// -------------------------------------------------------------------------
15152	//
15153	//
15154
15155	/// \name Types
15156	/// Implementations are in SemaType.cpp
15157	///@{
15158
15159	public:
15160	/// A mapping that describes the nullability we've seen in each header file.
15161	FileNullabilityMap NullabilityMap;
15162
15163	static int getPrintable(int I) { return I; }
15164	static unsigned getPrintable(unsigned I) { return I; }
15165	static bool getPrintable(bool B) { return B; }
15166	static const char getPrintable(const* char S) { return* S; }
15167	static StringRef getPrintable(StringRef S) { return S; }
15168	static const std::string &getPrintable(const std::string &S) { return S; }
15169	static const IdentifierInfo getPrintable(const* IdentifierInfo *II) {
15170	return II;
15171	}
15172	static DeclarationName getPrintable(DeclarationName N) { return N; }
15173	static QualType getPrintable(QualType T) { return T; }
15174	static SourceRange getPrintable(SourceRange R) { return R; }
15175	static SourceRange getPrintable(SourceLocation L) { return L; }
15176	static SourceRange getPrintable(const Expr E) { return* E->getSourceRange(); }
15177	static SourceRange getPrintable(TypeLoc TL) { return TL.getSourceRange(); }
15178
15179	enum class CompleteTypeKind {
15180	/// Apply the normal rules for complete types. In particular,
15181	/// treat all sizeless types as incomplete.
15182	Normal,
15183
15184	/// Relax the normal rules for complete types so that they include
15185	/// sizeless built-in types.
15186	AcceptSizeless,
15187
15188	// FIXME: Eventually we should flip the default to Normal and opt in
15189	// to AcceptSizeless rather than opt out of it.
15190	Default = AcceptSizeless
15191	};
15192
15193	QualType BuildQualifiedType(QualType T, SourceLocation Loc, Qualifiers Qs,
15194	const DeclSpec DS = nullptr*);
15195	QualType BuildQualifiedType(QualType T, SourceLocation Loc, unsigned CVRA,
15196	const DeclSpec DS = nullptr*);
15197
15198	/// Build a pointer type.
15199	///
15200	/// \param T The type to which we'll be building a pointer.
15201	///
15202	/// \param Loc The location of the entity whose type involves this
15203	/// pointer type or, if there is no such entity, the location of the
15204	/// type that will have pointer type.
15205	///
15206	/// \param Entity The name of the entity that involves the pointer
15207	/// type, if known.
15208	///
15209	/// \returns A suitable pointer type, if there are no
15210	/// errors. Otherwise, returns a NULL type.
15211	QualType BuildPointerType(QualType T, SourceLocation Loc,
15212	DeclarationName Entity);
15213
15214	/// Build a reference type.
15215	///
15216	/// \param T The type to which we'll be building a reference.
15217	///
15218	/// \param Loc The location of the entity whose type involves this
15219	/// reference type or, if there is no such entity, the location of the
15220	/// type that will have reference type.
15221	///
15222	/// \param Entity The name of the entity that involves the reference
15223	/// type, if known.
15224	///
15225	/// \returns A suitable reference type, if there are no
15226	/// errors. Otherwise, returns a NULL type.
15227	QualType BuildReferenceType(QualType T, bool LValueRef, SourceLocation Loc,
15228	DeclarationName Entity);
15229
15230	/// Build an array type.
15231	///
15232	/// \param T The type of each element in the array.
15233	///
15234	/// \param ASM C99 array size modifier (e.g., '', 'static').*
15235	///
15236	/// \param ArraySize Expression describing the size of the array.
15237	///
15238	/// \param Brackets The range from the opening '[' to the closing ']'.
15239	///
15240	/// \param Entity The name of the entity that involves the array
15241	/// type, if known.
15242	///
15243	/// \returns A suitable array type, if there are no errors. Otherwise,
15244	/// returns a NULL type.
15245	QualType BuildArrayType(QualType T, ArraySizeModifier ASM, Expr *ArraySize,
15246	unsigned Quals, SourceRange Brackets,
15247	DeclarationName Entity);
15248	QualType BuildVectorType(QualType T, Expr *VecSize, SourceLocation AttrLoc);
15249
15250	/// Build an ext-vector type.
15251	///
15252	/// Run the required checks for the extended vector type.
15253	QualType BuildExtVectorType(QualType T, Expr *ArraySize,
15254	SourceLocation AttrLoc);
15255	QualType BuildMatrixType(QualType T, Expr NumRows, Expr NumColumns,
15256	SourceLocation AttrLoc);
15257
15258	QualType BuildCountAttributedArrayOrPointerType(QualType WrappedTy,
15259	Expr *CountExpr,
15260	bool CountInBytes,
15261	bool OrNull);
15262
15263	/// BuildAddressSpaceAttr - Builds a DependentAddressSpaceType if an
15264	/// expression is uninstantiated. If instantiated it will apply the
15265	/// appropriate address space to the type. This function allows dependent
15266	/// template variables to be used in conjunction with the address_space
15267	/// attribute
15268	QualType BuildAddressSpaceAttr(QualType &T, LangAS ASIdx, Expr *AddrSpace,
15269	SourceLocation AttrLoc);
15270
15271	/// Same as above, but constructs the AddressSpace index if not provided.
15272	QualType BuildAddressSpaceAttr(QualType &T, Expr *AddrSpace,
15273	SourceLocation AttrLoc);
15274
15275	bool CheckQualifiedFunctionForTypeId(QualType T, SourceLocation Loc);
15276
15277	bool CheckFunctionReturnType(QualType T, SourceLocation Loc);
15278
15279	/// Build a function type.
15280	///
15281	/// This routine checks the function type according to C++ rules and
15282	/// under the assumption that the result type and parameter types have
15283	/// just been instantiated from a template. It therefore duplicates
15284	/// some of the behavior of GetTypeForDeclarator, but in a much
15285	/// simpler form that is only suitable for this narrow use case.
15286	///
15287	/// \param T The return type of the function.
15288	///
15289	/// \param ParamTypes The parameter types of the function. This array
15290	/// will be modified to account for adjustments to the types of the
15291	/// function parameters.
15292	///
15293	/// \param Loc The location of the entity whose type involves this
15294	/// function type or, if there is no such entity, the location of the
15295	/// type that will have function type.
15296	///
15297	/// \param Entity The name of the entity that involves the function
15298	/// type, if known.
15299	///
15300	/// \param EPI Extra information about the function type. Usually this will
15301	/// be taken from an existing function with the same prototype.
15302	///
15303	/// \returns A suitable function type, if there are no errors. The
15304	/// unqualified type will always be a FunctionProtoType.
15305	/// Otherwise, returns a NULL type.
15306	QualType BuildFunctionType(QualType T, MutableArrayRef<QualType> ParamTypes,
15307	SourceLocation Loc, DeclarationName Entity,
15308	const FunctionProtoType::ExtProtoInfo &EPI);
15309
15310	/// Build a member pointer type \c T Class::.*
15311	///
15312	/// \param T the type to which the member pointer refers.
15313	/// \param Class the class type into which the member pointer points.
15314	/// \param Loc the location where this type begins
15315	/// \param Entity the name of the entity that will have this member pointer
15316	/// type
15317	///
15318	/// \returns a member pointer type, if successful, or a NULL type if there was
15319	/// an error.
15320	QualType BuildMemberPointerType(QualType T, const CXXScopeSpec &SS,
15321	CXXRecordDecl *Cls, SourceLocation Loc,
15322	DeclarationName Entity);
15323
15324	/// Build a block pointer type.
15325	///
15326	/// \param T The type to which we'll be building a block pointer.
15327	///
15328	/// \param Loc The source location, used for diagnostics.
15329	///
15330	/// \param Entity The name of the entity that involves the block pointer
15331	/// type, if known.
15332	///
15333	/// \returns A suitable block pointer type, if there are no
15334	/// errors. Otherwise, returns a NULL type.
15335	QualType BuildBlockPointerType(QualType T, SourceLocation Loc,
15336	DeclarationName Entity);
15337
15338	/// Build a paren type including \p T.
15339	QualType BuildParenType(QualType T);
15340	QualType BuildAtomicType(QualType T, SourceLocation Loc);
15341
15342	/// Build a Read-only Pipe type.
15343	///
15344	/// \param T The type to which we'll be building a Pipe.
15345	///
15346	/// \param Loc We do not use it for now.
15347	///
15348	/// \returns A suitable pipe type, if there are no errors. Otherwise, returns
15349	/// a NULL type.
15350	QualType BuildReadPipeType(QualType T, SourceLocation Loc);
15351
15352	/// Build a Write-only Pipe type.
15353	///
15354	/// \param T The type to which we'll be building a Pipe.
15355	///
15356	/// \param Loc We do not use it for now.
15357	///
15358	/// \returns A suitable pipe type, if there are no errors. Otherwise, returns
15359	/// a NULL type.
15360	QualType BuildWritePipeType(QualType T, SourceLocation Loc);
15361
15362	/// Build a bit-precise integer type.
15363	///
15364	/// \param IsUnsigned Boolean representing the signedness of the type.
15365	///
15366	/// \param BitWidth Size of this int type in bits, or an expression
15367	/// representing that.
15368	///
15369	/// \param Loc Location of the keyword.
15370	QualType BuildBitIntType(bool IsUnsigned, Expr *BitWidth, SourceLocation Loc);
15371
15372	/// GetTypeForDeclarator - Convert the type for the specified
15373	/// declarator to Type instances.
15374	///
15375	/// The result of this call will never be null, but the associated
15376	/// type may be a null type if there's an unrecoverable error.
15377	TypeSourceInfo *GetTypeForDeclarator(Declarator &D);
15378	TypeSourceInfo *GetTypeForDeclaratorCast(Declarator &D, QualType FromTy);
15379
15380	/// Package the given type and TSI into a ParsedType.
15381	ParsedType CreateParsedType(QualType T, TypeSourceInfo *TInfo);
15382	static QualType GetTypeFromParser(ParsedType Ty,
15383	TypeSourceInfo TInfo = nullptr**);
15384
15385	TypeResult ActOnTypeName(Declarator &D);
15386
15387	// Check whether the size of array element of type \p EltTy is a multiple of
15388	// its alignment and return false if it isn't.
15389	bool checkArrayElementAlignment(QualType EltTy, SourceLocation Loc);
15390
15391	void
15392	diagnoseIgnoredQualifiers(unsigned DiagID, unsigned Quals,
15393	SourceLocation FallbackLoc,
15394	SourceLocation ConstQualLoc = SourceLocation (),
15395	SourceLocation VolatileQualLoc = SourceLocation (),
15396	SourceLocation RestrictQualLoc = SourceLocation (),
15397	SourceLocation AtomicQualLoc = SourceLocation (),
15398	SourceLocation UnalignedQualLoc = SourceLocation ());
15399
15400	/// Retrieve the keyword associated
15401	IdentifierInfo *getNullabilityKeyword(NullabilityKind nullability);
15402
15403	/// Adjust the calling convention of a method to be the ABI default if it
15404	/// wasn't specified explicitly. This handles method types formed from
15405	/// function type typedefs and typename template arguments.
15406	void adjustMemberFunctionCC(QualType &T, bool HasThisPointer,
15407	bool IsCtorOrDtor, SourceLocation Loc);
15408
15409	// Check if there is an explicit attribute, but only look through parens.
15410	// The intent is to look for an attribute on the current declarator, but not
15411	// one that came from a typedef.
15412	bool hasExplicitCallingConv(QualType T);
15413
15414	/// Check whether a nullability type specifier can be added to the given
15415	/// type through some means not written in source (e.g. API notes).
15416	///
15417	/// \param Type The type to which the nullability specifier will be
15418	/// added. On success, this type will be updated appropriately.
15419	///
15420	/// \param Nullability The nullability specifier to add.
15421	///
15422	/// \param DiagLoc The location to use for diagnostics.
15423	///
15424	/// \param AllowArrayTypes Whether to accept nullability specifiers on an
15425	/// array type (e.g., because it will decay to a pointer).
15426	///
15427	/// \param OverrideExisting Whether to override an existing, locally-specified
15428	/// nullability specifier rather than complaining about the conflict.
15429	///
15430	/// \returns true if nullability cannot be applied, false otherwise.
15431	bool CheckImplicitNullabilityTypeSpecifier(QualType &Type,
15432	NullabilityKind Nullability,
15433	SourceLocation DiagLoc,
15434	bool AllowArrayTypes,
15435	bool OverrideExisting);
15436
15437	/// Check whether the given variable declaration has a size that fits within
15438	/// the address space it is declared in. This issues a diagnostic if not.
15439	///
15440	/// \param VD The variable declaration to check the size of.
15441	///
15442	/// \param AS The address space to check the size of \p VD against.
15443	///
15444	/// \returns true if the variable's size fits within the address space, false
15445	/// otherwise.
15446	bool CheckVarDeclSizeAddressSpace(const VarDecl *VD, LangAS AS);
15447
15448	/// Get the type of expression E, triggering instantiation to complete the
15449	/// type if necessary -- that is, if the expression refers to a templated
15450	/// static data member of incomplete array type.
15451	///
15452	/// May still return an incomplete type if instantiation was not possible or
15453	/// if the type is incomplete for a different reason. Use
15454	/// RequireCompleteExprType instead if a diagnostic is expected for an
15455	/// incomplete expression type.
15456	QualType getCompletedType(Expr *E);
15457
15458	void completeExprArrayBound(Expr *E);
15459
15460	/// Ensure that the type of the given expression is complete.
15461	///
15462	/// This routine checks whether the expression \p E has a complete type. If
15463	/// the expression refers to an instantiable construct, that instantiation is
15464	/// performed as needed to complete its type. Furthermore
15465	/// Sema::RequireCompleteType is called for the expression's type (or in the
15466	/// case of a reference type, the referred-to type).
15467	///
15468	/// \param E The expression whose type is required to be complete.
15469	/// \param Kind Selects which completeness rules should be applied.
15470	/// \param Diagnoser The object that will emit a diagnostic if the type is
15471	/// incomplete.
15472	///
15473	/// \returns \c true if the type of \p E is incomplete and diagnosed, \c false
15474	/// otherwise.
15475	bool RequireCompleteExprType(Expr *E, CompleteTypeKind Kind,
15476	TypeDiagnoser &Diagnoser);
15477	bool RequireCompleteExprType(Expr E, unsigned* DiagID);
15478
15479	template <typename... Ts>
15480	bool RequireCompleteExprType(Expr E, unsigned* DiagID, const Ts &...Args) {
15481	BoundTypeDiagnoser<Ts...> Diagnoser(DiagID, Args...);
15482	return RequireCompleteExprType(E, CompleteTypeKind::Default, Diagnoser);
15483	}
15484
15485	// Returns the underlying type of a decltype with the given expression.
15486	QualType getDecltypeForExpr(Expr *E);
15487
15488	QualType BuildTypeofExprType(Expr *E, TypeOfKind Kind);
15489	/// If AsUnevaluated is false, E is treated as though it were an evaluated
15490	/// context, such as when building a type for decltype(auto).
15491	QualType BuildDecltypeType(Expr E, bool* AsUnevaluated = true);
15492
15493	QualType ActOnPackIndexingType(QualType Pattern, Expr *IndexExpr,
15494	SourceLocation Loc,
15495	SourceLocation EllipsisLoc);
15496	QualType BuildPackIndexingType(QualType Pattern, Expr *IndexExpr,
15497	SourceLocation Loc, SourceLocation EllipsisLoc,
15498	bool FullySubstituted = false,
15499	ArrayRef<QualType> Expansions = {});
15500
15501	using UTTKind = UnaryTransformType::UTTKind;
15502	QualType BuildUnaryTransformType(QualType BaseType, UTTKind UKind,
15503	SourceLocation Loc);
15504	QualType BuiltinEnumUnderlyingType(QualType BaseType, SourceLocation Loc);
15505	QualType BuiltinAddPointer(QualType BaseType, SourceLocation Loc);
15506	QualType BuiltinRemovePointer(QualType BaseType, SourceLocation Loc);
15507	QualType BuiltinDecay(QualType BaseType, SourceLocation Loc);
15508	QualType BuiltinAddReference(QualType BaseType, UTTKind UKind,
15509	SourceLocation Loc);
15510	QualType BuiltinRemoveExtent(QualType BaseType, UTTKind UKind,
15511	SourceLocation Loc);
15512	QualType BuiltinRemoveReference(QualType BaseType, UTTKind UKind,
15513	SourceLocation Loc);
15514
15515	QualType BuiltinRemoveCVRef(QualType BaseType, SourceLocation Loc) {
15516	return BuiltinRemoveReference(BaseType, UKind: UTTKind::RemoveCVRef, Loc);
15517	}
15518
15519	QualType BuiltinChangeCVRQualifiers(QualType BaseType, UTTKind UKind,
15520	SourceLocation Loc);
15521	QualType BuiltinChangeSignedness(QualType BaseType, UTTKind UKind,
15522	SourceLocation Loc);
15523
15524	bool BuiltinIsBaseOf(SourceLocation RhsTLoc, QualType LhsT, QualType RhsT);
15525
15526	/// Ensure that the type T is a literal type.
15527	///
15528	/// This routine checks whether the type @p T is a literal type. If @p T is an
15529	/// incomplete type, an attempt is made to complete it. If @p T is a literal
15530	/// type, or @p AllowIncompleteType is true and @p T is an incomplete type,
15531	/// returns false. Otherwise, this routine issues the diagnostic @p PD (giving
15532	/// it the type @p T), along with notes explaining why the type is not a
15533	/// literal type, and returns true.
15534	///
15535	/// @param Loc The location in the source that the non-literal type
15536	/// diagnostic should refer to.
15537	///
15538	/// @param T The type that this routine is examining for literalness.
15539	///
15540	/// @param Diagnoser Emits a diagnostic if T is not a literal type.
15541	///
15542	/// @returns @c true if @p T is not a literal type and a diagnostic was
15543	/// emitted, @c false otherwise.
15544	bool RequireLiteralType(SourceLocation Loc, QualType T,
15545	TypeDiagnoser &Diagnoser);
15546	bool RequireLiteralType(SourceLocation Loc, QualType T, unsigned DiagID);
15547
15548	template <typename... Ts>
15549	bool RequireLiteralType(SourceLocation Loc, QualType T, unsigned DiagID,
15550	const Ts &...Args) {
15551	BoundTypeDiagnoser<Ts...> Diagnoser(DiagID, Args...);
15552	return RequireLiteralType(Loc, T, Diagnoser);
15553	}
15554
15555	bool isCompleteType(SourceLocation Loc, QualType T,
15556	CompleteTypeKind Kind = CompleteTypeKind::Default) {
15557	return !RequireCompleteTypeImpl(Loc, T, Kind, Diagnoser: nullptr);
15558	}
15559
15560	/// Ensure that the type T is a complete type.
15561	///
15562	/// This routine checks whether the type @p T is complete in any
15563	/// context where a complete type is required. If @p T is a complete
15564	/// type, returns false. If @p T is a class template specialization,
15565	/// this routine then attempts to perform class template
15566	/// instantiation. If instantiation fails, or if @p T is incomplete
15567	/// and cannot be completed, issues the diagnostic @p diag (giving it
15568	/// the type @p T) and returns true.
15569	///
15570	/// @param Loc The location in the source that the incomplete type
15571	/// diagnostic should refer to.
15572	///
15573	/// @param T The type that this routine is examining for completeness.
15574	///
15575	/// @param Kind Selects which completeness rules should be applied.
15576	///
15577	/// @returns @c true if @p T is incomplete and a diagnostic was emitted,
15578	/// @c false otherwise.
15579	bool RequireCompleteType(SourceLocation Loc, QualType T,
15580	CompleteTypeKind Kind, TypeDiagnoser &Diagnoser);
15581	bool RequireCompleteType(SourceLocation Loc, QualType T,
15582	CompleteTypeKind Kind, unsigned DiagID);
15583
15584	bool RequireCompleteType(SourceLocation Loc, QualType T,
15585	TypeDiagnoser &Diagnoser) {
15586	return RequireCompleteType(Loc, T, Kind: CompleteTypeKind::Default, Diagnoser);
15587	}
15588	bool RequireCompleteType(SourceLocation Loc, QualType T, unsigned DiagID) {
15589	return RequireCompleteType(Loc, T, Kind: CompleteTypeKind::Default, DiagID);
15590	}
15591
15592	template <typename... Ts>
15593	bool RequireCompleteType(SourceLocation Loc, QualType T, unsigned DiagID,
15594	const Ts &...Args) {
15595	BoundTypeDiagnoser<Ts...> Diagnoser(DiagID, Args...);
15596	return RequireCompleteType(Loc, T, Diagnoser);
15597	}
15598
15599	/// Determine whether a declaration is visible to name lookup.
15600	bool isVisible(const NamedDecl *D) {
15601	return D->isUnconditionallyVisible() \|\|
15602	isAcceptableSlow(D, Kind: AcceptableKind::Visible);
15603	}
15604
15605	/// Determine whether a declaration is reachable.
15606	bool isReachable(const NamedDecl *D) {
15607	// All visible declarations are reachable.
15608	return D->isUnconditionallyVisible() \|\|
15609	isAcceptableSlow(D, Kind: AcceptableKind::Reachable);
15610	}
15611
15612	/// Determine whether a declaration is acceptable (visible/reachable).
15613	bool isAcceptable(const NamedDecl *D, AcceptableKind Kind) {
15614	return Kind == AcceptableKind::Visible ? isVisible(D) : isReachable(D);
15615	}
15616
15617	/// Determine if \p D and \p Suggested have a structurally compatible
15618	/// layout as described in C11 6.2.7/1.
15619	bool hasStructuralCompatLayout(Decl D, Decl Suggested);
15620
15621	/// Determine if \p D has a visible definition. If not, suggest a declaration
15622	/// that should be made visible to expose the definition.
15623	bool hasVisibleDefinition(NamedDecl D, NamedDecl *Suggested,
15624	bool OnlyNeedComplete = false);
15625	bool hasVisibleDefinition(const NamedDecl *D) {
15626	NamedDecl *Hidden;
15627	return hasVisibleDefinition(D: const_cast<NamedDecl *>(D), Suggested: &Hidden);
15628	}
15629	/// Determine if \p D has a definition which allows we redefine it in current
15630	/// TU. \p Suggested is the definition that should be made visible to expose
15631	/// the definition.
15632	bool isRedefinitionAllowedFor(NamedDecl D, NamedDecl *Suggested,
15633	bool &Visible);
15634	bool isRedefinitionAllowedFor(const NamedDecl D, bool* &Visible) {
15635	NamedDecl *Hidden;
15636	return isRedefinitionAllowedFor(D: const_cast<NamedDecl *>(D), Suggested: &Hidden,
15637	Visible);
15638	}
15639
15640	/// Determine if \p D has a reachable definition. If not, suggest a
15641	/// declaration that should be made reachable to expose the definition.
15642	bool hasReachableDefinition(NamedDecl D, NamedDecl *Suggested,
15643	bool OnlyNeedComplete = false);
15644	bool hasReachableDefinition(NamedDecl *D) {
15645	NamedDecl *Hidden;
15646	return hasReachableDefinition(D, Suggested: &Hidden);
15647	}
15648
15649	bool hasAcceptableDefinition(NamedDecl D, NamedDecl *Suggested,
15650	AcceptableKind Kind,
15651	bool OnlyNeedComplete = false);
15652	bool hasAcceptableDefinition(NamedDecl *D, AcceptableKind Kind) {
15653	NamedDecl *Hidden;
15654	return hasAcceptableDefinition(D, Suggested: &Hidden, Kind);
15655	}
15656
15657	/// Try to parse the conditional expression attached to an effect attribute
15658	/// (e.g. 'nonblocking'). (c.f. Sema::ActOnNoexceptSpec). Return an empty
15659	/// optional on error.
15660	std::optional<FunctionEffectMode>
15661	ActOnEffectExpression(Expr *CondExpr, StringRef AttributeName);
15662
15663	void ActOnCleanupAttr(Decl D, const* Attr *A);
15664	void ActOnInitPriorityAttr(Decl D, const* Attr *A);
15665
15666	private:
15667	/// The implementation of RequireCompleteType
15668	bool RequireCompleteTypeImpl(SourceLocation Loc, QualType T,
15669	CompleteTypeKind Kind, TypeDiagnoser *Diagnoser);
15670
15671	/// Nullability type specifiers.
15672	IdentifierInfo Ident__Nonnull = nullptr*;
15673	IdentifierInfo Ident__Nullable = nullptr*;
15674	IdentifierInfo Ident__Nullable_result = nullptr*;
15675	IdentifierInfo Ident__Null_unspecified = nullptr*;
15676
15677	///@}
15678
15679	//
15680	//
15681	// -------------------------------------------------------------------------
15682	//
15683	//
15684
15685	/// \name FixIt Helpers
15686	/// Implementations are in SemaFixItUtils.cpp
15687	///@{
15688
15689	public:
15690	/// Get a string to suggest for zero-initialization of a type.
15691	std::string getFixItZeroInitializerForType(QualType T,
15692	SourceLocation Loc) const;
15693	std::string getFixItZeroLiteralForType(QualType T, SourceLocation Loc) const;
15694
15695	///@}
15696
15697	//
15698	//
15699	// -------------------------------------------------------------------------
15700	//
15701	//
15702
15703	/// \name Function Effects
15704	/// Implementations are in SemaFunctionEffects.cpp
15705	///@{
15706	public:
15707	struct FunctionEffectDiff {
15708	enum class Kind { Added, Removed, ConditionMismatch };
15709
15710	FunctionEffect::Kind EffectKind;
15711	Kind DiffKind;
15712	std::optional<FunctionEffectWithCondition>
15713	Old; // Invalid when 'Kind' is 'Added'.
15714	std::optional<FunctionEffectWithCondition>
15715	New; // Invalid when 'Kind' is 'Removed'.
15716
15717	StringRef effectName() const {
15718	if (Old)
15719	return Old.value().Effect.name();
15720	return New.value().Effect.name();
15721	}
15722
15723	/// Describes the result of effects differing between a base class's virtual
15724	/// method and an overriding method in a subclass.
15725	enum class OverrideResult {
15726	NoAction,
15727	Warn,
15728	Merge // Merge missing effect from base to derived.
15729	};
15730
15731	/// Return true if adding or removing the effect as part of a type
15732	/// conversion should generate a diagnostic.
15733	bool shouldDiagnoseConversion(QualType SrcType,
15734	const FunctionEffectsRef &SrcFX,
15735	QualType DstType,
15736	const FunctionEffectsRef &DstFX) const;
15737
15738	/// Return true if adding or removing the effect in a redeclaration should
15739	/// generate a diagnostic.
15740	bool shouldDiagnoseRedeclaration(const FunctionDecl &OldFunction,
15741	const FunctionEffectsRef &OldFX,
15742	const FunctionDecl &NewFunction,
15743	const FunctionEffectsRef &NewFX) const;
15744
15745	/// Return true if adding or removing the effect in a C++ virtual method
15746	/// override should generate a diagnostic.
15747	OverrideResult shouldDiagnoseMethodOverride(
15748	const CXXMethodDecl &OldMethod, const FunctionEffectsRef &OldFX,
15749	const CXXMethodDecl &NewMethod, const FunctionEffectsRef &NewFX) const;
15750	};
15751
15752	struct FunctionEffectDiffVector : public SmallVector<FunctionEffectDiff> {
15753	/// Caller should short-circuit by checking for equality first.
15754	FunctionEffectDiffVector(const FunctionEffectsRef &Old,
15755	const FunctionEffectsRef &New);
15756	};
15757
15758	/// All functions/lambdas/blocks which have bodies and which have a non-empty
15759	/// FunctionEffectsRef to be verified.
15760	SmallVector<const Decl *> DeclsWithEffectsToVerify;
15761
15762	/// The union of all effects present on DeclsWithEffectsToVerify. Conditions
15763	/// are all null.
15764	FunctionEffectKindSet AllEffectsToVerify;
15765
15766	public:
15767	/// Warn and return true if adding a function effect to a set would create a
15768	/// conflict.
15769	bool diagnoseConflictingFunctionEffect(const FunctionEffectsRef &FX,
15770	const FunctionEffectWithCondition &EC,
15771	SourceLocation NewAttrLoc);
15772
15773	// Report a failure to merge function effects between declarations due to a
15774	// conflict.
15775	void
15776	diagnoseFunctionEffectMergeConflicts(const FunctionEffectSet::Conflicts &Errs,
15777	SourceLocation NewLoc,
15778	SourceLocation OldLoc);
15779
15780	/// Inline checks from the start of maybeAddDeclWithEffects, to
15781	/// minimize performance impact on code not using effects.
15782	template <class FuncOrBlockDecl>
15783	void maybeAddDeclWithEffects(FuncOrBlockDecl *D) {
15784	if (Context.hasAnyFunctionEffects())
15785	if (FunctionEffectsRef FX = D->getFunctionEffects(); !FX.empty())
15786	maybeAddDeclWithEffects(D, FX);
15787	}
15788
15789	/// Potentially add a FunctionDecl or BlockDecl to DeclsWithEffectsToVerify.
15790	void maybeAddDeclWithEffects(const Decl D, const* FunctionEffectsRef &FX);
15791
15792	/// Unconditionally add a Decl to DeclsWithEfffectsToVerify.
15793	void addDeclWithEffects(const Decl D, const* FunctionEffectsRef &FX);
15794
15795	void performFunctionEffectAnalysis(TranslationUnitDecl *TU);
15796
15797	///@}
15798	};
15799
15800	DeductionFailureInfo
15801	MakeDeductionFailureInfo(ASTContext &Context, TemplateDeductionResult TDK,
15802	sema::TemplateDeductionInfo &Info);
15803
15804	/// Contains a late templated function.
15805	/// Will be parsed at the end of the translation unit, used by Sema & Parser.
15806	struct LateParsedTemplate {
15807	CachedTokens Toks;
15808	/// The template function declaration to be late parsed.
15809	Decl *D;
15810	/// Floating-point options in the point of definition.
15811	FPOptions FPO;
15812	};
15813
15814	template <>
15815	void Sema::PragmaStack<Sema::AlignPackInfo>::Act(SourceLocation PragmaLocation,
15816	PragmaMsStackAction Action,
15817	llvm::StringRef StackSlotLabel,
15818	AlignPackInfo Value);
15819
15820	} // end namespace clang
15821
15822	#endif
15823

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