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	/// Determine if VD, which must be a variable or function, is an external
972	/// symbol that nonetheless can't be referenced from outside this translation
973	/// unit because its type has no linkage and it's not extern "C".
974	bool isExternalWithNoLinkageType(const ValueDecl VD) const*;
975
976	/// Obtain a sorted list of functions that are undefined but ODR-used.
977	void getUndefinedButUsed(
978	SmallVectorImpl<std::pair<NamedDecl *, SourceLocation>> &Undefined);
979
980	typedef std::pair<SourceLocation, bool> DeleteExprLoc;
981	typedef llvm::SmallVector<DeleteExprLoc, `4`> DeleteLocs;
982	/// Retrieves list of suspicious delete-expressions that will be checked at
983	/// the end of translation unit.
984	const llvm::MapVector<FieldDecl *, DeleteLocs> &
985	getMismatchingDeleteExpressions() const;
986
987	/// Cause the built diagnostic to be emitted on the DiagosticsEngine.
988	/// This is closely coupled to the SemaDiagnosticBuilder class and
989	/// should not be used elsewhere.
990	void EmitDiagnostic(unsigned DiagID, const DiagnosticBuilder &DB);
991
992	void addImplicitTypedef(StringRef Name, QualType T);
993
994	/// Whether uncompilable error has occurred. This includes error happens
995	/// in deferred diagnostics.
996	bool hasUncompilableErrorOccurred() const;
997
998	/// Looks through the macro-expansion chain for the given
999	/// location, looking for a macro expansion with the given name.
1000	/// If one is found, returns true and sets the location to that
1001	/// expansion loc.
1002	bool findMacroSpelling(SourceLocation &loc, StringRef name);
1003
1004	/// Calls \c Lexer::getLocForEndOfToken()
1005	SourceLocation getLocForEndOfToken(SourceLocation Loc, unsigned Offset = `0`);
1006
1007	/// Calls \c Lexer::findNextToken() to find the next token, and if the
1008	/// locations of both ends of the token can be resolved it return that
1009	/// range; Otherwise it returns an invalid SourceRange.
1010	SourceRange getRangeForNextToken(
1011	SourceLocation Loc, bool IncludeMacros, bool IncludeComments,
1012	std::optional<tok::TokenKind> ExpectedToken = std::nullopt);
1013
1014	/// Retrieve the module loader associated with the preprocessor.
1015	ModuleLoader &getModuleLoader() const;
1016
1017	/// Invent a new identifier for parameters of abbreviated templates.
1018	IdentifierInfo *
1019	InventAbbreviatedTemplateParameterTypeName(const IdentifierInfo *ParamName,
1020	unsigned Index);
1021
1022	void emitAndClearUnusedLocalTypedefWarnings();
1023
1024	// Emit all deferred diagnostics.
1025	void emitDeferredDiags();
1026
1027	/// This is called before the very first declaration in the translation unit
1028	/// is parsed. Note that the ASTContext may have already injected some
1029	/// declarations.
1030	void ActOnStartOfTranslationUnit();
1031	/// ActOnEndOfTranslationUnit - This is called at the very end of the
1032	/// translation unit when EOF is reached and all but the top-level scope is
1033	/// popped.
1034	void ActOnEndOfTranslationUnit();
1035	void ActOnEndOfTranslationUnitFragment(TUFragmentKind Kind);
1036
1037	/// Determines the active Scope associated with the given declaration
1038	/// context.
1039	///
1040	/// This routine maps a declaration context to the active Scope object that
1041	/// represents that declaration context in the parser. It is typically used
1042	/// from "scope-less" code (e.g., template instantiation, lazy creation of
1043	/// declarations) that injects a name for name-lookup purposes and, therefore,
1044	/// must update the Scope.
1045	///
1046	/// \returns The scope corresponding to the given declaraion context, or NULL
1047	/// if no such scope is open.
1048	Scope getScopeForContext(DeclContext Ctx);
1049
1050	void PushFunctionScope();
1051	void PushBlockScope(Scope BlockScope, BlockDecl Block);
1052	sema::LambdaScopeInfo *PushLambdaScope();
1053
1054	/// This is used to inform Sema what the current TemplateParameterDepth
1055	/// is during Parsing. Currently it is used to pass on the depth
1056	/// when parsing generic lambda 'auto' parameters.
1057	void RecordParsingTemplateParameterDepth(unsigned Depth);
1058
1059	void PushCapturedRegionScope(Scope RegionScope, CapturedDecl CD,
1060	RecordDecl *RD, CapturedRegionKind K,
1061	unsigned OpenMPCaptureLevel = `0`);
1062
1063	/// Custom deleter to allow FunctionScopeInfos to be kept alive for a short
1064	/// time after they've been popped.
1065	class PoppedFunctionScopeDeleter {
1066	Sema *Self;
1067
1068	public:
1069	explicit PoppedFunctionScopeDeleter(Sema *Self) : Self(Self) {}
1070	void operator()(sema::FunctionScopeInfo Scope) const*;
1071	};
1072
1073	using PoppedFunctionScopePtr =
1074	std::unique_ptr<sema::FunctionScopeInfo, PoppedFunctionScopeDeleter>;
1075
1076	/// Pop a function (or block or lambda or captured region) scope from the
1077	/// stack.
1078	///
1079	/// \param WP The warning policy to use for CFG-based warnings, or null if
1080	/// such warnings should not be produced.
1081	/// \param D The declaration corresponding to this function scope, if
1082	/// producing CFG-based warnings.
1083	/// \param BlockType The type of the block expression, if D is a BlockDecl.
1084	PoppedFunctionScopePtr
1085	PopFunctionScopeInfo(const sema::AnalysisBasedWarnings::Policy WP = nullptr*,
1086	Decl D = nullptr*, QualType BlockType = QualType ());
1087
1088	sema::FunctionScopeInfo getEnclosingFunction() const*;
1089
1090	void setFunctionHasBranchIntoScope();
1091	void setFunctionHasBranchProtectedScope();
1092	void setFunctionHasIndirectGoto();
1093	void setFunctionHasMustTail();
1094
1095	void PushCompoundScope(bool IsStmtExpr);
1096	void PopCompoundScope();
1097
1098	/// Determine whether any errors occurred within this function/method/
1099	/// block.
1100	bool hasAnyUnrecoverableErrorsInThisFunction() const;
1101
1102	/// Retrieve the current block, if any.
1103	sema::BlockScopeInfo *getCurBlock();
1104
1105	/// Get the innermost lambda or block enclosing the current location, if any.
1106	/// This looks through intervening non-lambda, non-block scopes such as local
1107	/// functions.
1108	sema::CapturingScopeInfo getEnclosingLambdaOrBlock() const*;
1109
1110	/// Retrieve the current lambda scope info, if any.
1111	/// \param IgnoreNonLambdaCapturingScope true if should find the top-most
1112	/// lambda scope info ignoring all inner capturing scopes that are not
1113	/// lambda scopes.
1114	sema::LambdaScopeInfo *
1115	getCurLambda(bool IgnoreNonLambdaCapturingScope = false);
1116
1117	/// Retrieve the current generic lambda info, if any.
1118	sema::LambdaScopeInfo *getCurGenericLambda();
1119
1120	/// Retrieve the current captured region, if any.
1121	sema::CapturedRegionScopeInfo *getCurCapturedRegion();
1122
1123	void ActOnComment(SourceRange Comment);
1124
1125	/// Retrieve the parser's current scope.
1126	///
1127	/// This routine must only be used when it is certain that semantic analysis
1128	/// and the parser are in precisely the same context, which is not the case
1129	/// when, e.g., we are performing any kind of template instantiation.
1130	/// Therefore, the only safe places to use this scope are in the parser
1131	/// itself and in routines directly invoked from the parser and never* from*
1132	/// template substitution or instantiation.
1133	Scope getCurScope() const* { return CurScope; }
1134
1135	IdentifierInfo getSuperIdentifier() const*;
1136
1137	DeclContext getCurLexicalContext() const* {
1138	return OriginalLexicalContext ? OriginalLexicalContext : CurContext;
1139	}
1140
1141	SemaDiagnosticBuilder targetDiag(SourceLocation Loc, unsigned DiagID,
1142	const FunctionDecl FD = nullptr*);
1143	SemaDiagnosticBuilder targetDiag(SourceLocation Loc,
1144	const PartialDiagnostic &PD,
1145	const FunctionDecl FD = nullptr*) {
1146	return targetDiag(Loc, DiagID: PD.getDiagID(), FD) << PD;
1147	}
1148
1149	/// Check if the type is allowed to be used for the current target.
1150	void checkTypeSupport(QualType Ty, SourceLocation Loc,
1151	ValueDecl D = nullptr*);
1152
1153	/// ImpCastExprToType - If Expr is not of type 'Type', insert an implicit
1154	/// cast. If there is already an implicit cast, merge into the existing one.
1155	/// If isLvalue, the result of the cast is an lvalue.
1156	ExprResult ImpCastExprToType(
1157	Expr *E, QualType Type, CastKind CK, ExprValueKind VK = VK_PRValue,
1158	const CXXCastPath BasePath = nullptr*,
1159	CheckedConversionKind CCK = CheckedConversionKind::Implicit);
1160
1161	/// ScalarTypeToBooleanCastKind - Returns the cast kind corresponding
1162	/// to the conversion from scalar type ScalarTy to the Boolean type.
1163	static CastKind ScalarTypeToBooleanCastKind(QualType ScalarTy);
1164
1165	/// If \p AllowLambda is true, treat lambda as function.
1166	DeclContext getFunctionLevelDeclContext(bool* AllowLambda = false) const;
1167
1168	/// Returns a pointer to the innermost enclosing function, or nullptr if the
1169	/// current context is not inside a function. If \p AllowLambda is true,
1170	/// this can return the call operator of an enclosing lambda, otherwise
1171	/// lambdas are skipped when looking for an enclosing function.
1172	FunctionDecl getCurFunctionDecl(bool* AllowLambda = false) const;
1173
1174	/// getCurMethodDecl - If inside of a method body, this returns a pointer to
1175	/// the method decl for the method being parsed. If we're currently
1176	/// in a 'block', this returns the containing context.
1177	ObjCMethodDecl *getCurMethodDecl();
1178
1179	/// getCurFunctionOrMethodDecl - Return the Decl for the current ObjC method
1180	/// or C function we're in, otherwise return null. If we're currently
1181	/// in a 'block', this returns the containing context.
1182	NamedDecl getCurFunctionOrMethodDecl() const*;
1183
1184	/// Warn if we're implicitly casting from a _Nullable pointer type to a
1185	/// _Nonnull one.
1186	void diagnoseNullableToNonnullConversion(QualType DstType, QualType SrcType,
1187	SourceLocation Loc);
1188
1189	/// Warn when implicitly casting 0 to nullptr.
1190	void diagnoseZeroToNullptrConversion(CastKind Kind, const Expr *E);
1191
1192	/// Warn when implicitly changing function effects.
1193	void diagnoseFunctionEffectConversion(QualType DstType, QualType SrcType,
1194	SourceLocation Loc);
1195
1196	/// makeUnavailableInSystemHeader - There is an error in the current
1197	/// context. If we're still in a system header, and we can plausibly
1198	/// make the relevant declaration unavailable instead of erroring, do
1199	/// so and return true.
1200	bool makeUnavailableInSystemHeader(SourceLocation loc,
1201	UnavailableAttr::ImplicitReason reason);
1202
1203	/// Retrieve a suitable printing policy for diagnostics.
1204	PrintingPolicy getPrintingPolicy() const {
1205	return getPrintingPolicy(Ctx: Context, PP);
1206	}
1207
1208	/// Retrieve a suitable printing policy for diagnostics.
1209	static PrintingPolicy getPrintingPolicy(const ASTContext &Ctx,
1210	const Preprocessor &PP);
1211
1212	/// Scope actions.
1213	void ActOnTranslationUnitScope(Scope *S);
1214
1215	/// Determine whether \param D is function like (function or function
1216	/// template) for parsing.
1217	bool isDeclaratorFunctionLike(Declarator &D);
1218
1219	/// The maximum alignment, same as in llvm::Value. We duplicate them here
1220	/// because that allows us not to duplicate the constants in clang code,
1221	/// which we must to since we can't directly use the llvm constants.
1222	/// The value is verified against llvm here: lib/CodeGen/CGDecl.cpp
1223	///
1224	/// This is the greatest alignment value supported by load, store, and alloca
1225	/// instructions, and global values.
1226	static const unsigned MaxAlignmentExponent = `32`;
1227	static const uint64_t MaximumAlignment = `1ull` << MaxAlignmentExponent;
1228
1229	/// Flag indicating whether or not to collect detailed statistics.
1230	bool CollectStats;
1231
1232	std::unique_ptr<sema::FunctionScopeInfo> CachedFunctionScope;
1233
1234	/// Stack containing information about each of the nested
1235	/// function, block, and method scopes that are currently active.
1236	SmallVector<sema::FunctionScopeInfo *, `4`> FunctionScopes;
1237
1238	/// The index of the first FunctionScope that corresponds to the current
1239	/// context.
1240	unsigned FunctionScopesStart = `0`;
1241
1242	/// Track the number of currently active capturing scopes.
1243	unsigned CapturingFunctionScopes = `0`;
1244
1245	llvm::BumpPtrAllocator BumpAlloc;
1246
1247	/// The kind of translation unit we are processing.
1248	///
1249	/// When we're processing a complete translation unit, Sema will perform
1250	/// end-of-translation-unit semantic tasks (such as creating
1251	/// initializers for tentative definitions in C) once parsing has
1252	/// completed. Modules and precompiled headers perform different kinds of
1253	/// checks.
1254	const TranslationUnitKind TUKind;
1255
1256	/// Translation Unit Scope - useful to Objective-C actions that need
1257	/// to lookup file scope declarations in the "ordinary" C decl namespace.
1258	/// For example, user-defined classes, built-in "id" type, etc.
1259	Scope *TUScope;
1260
1261	void incrementMSManglingNumber() const {
1262	return CurScope->incrementMSManglingNumber();
1263	}
1264
1265	/// Try to recover by turning the given expression into a
1266	/// call. Returns true if recovery was attempted or an error was
1267	/// emitted; this may also leave the ExprResult invalid.
1268	bool tryToRecoverWithCall(ExprResult &E, const PartialDiagnostic &PD,
1269	bool ForceComplain = false,
1270	bool (IsPlausibleResult)(QualType) = nullptr*);
1271
1272	// Adds implicit lifetime bound attribute for implicit this to its
1273	// TypeSourceInfo.
1274	void addLifetimeBoundToImplicitThis(CXXMethodDecl *MD);
1275
1276	/// Figure out if an expression could be turned into a call.
1277	///
1278	/// Use this when trying to recover from an error where the programmer may
1279	/// have written just the name of a function instead of actually calling it.
1280	///
1281	/// \param E - The expression to examine.
1282	/// \param ZeroArgCallReturnTy - If the expression can be turned into a call
1283	/// with no arguments, this parameter is set to the type returned by such a
1284	/// call; otherwise, it is set to an empty QualType.
1285	/// \param OverloadSet - If the expression is an overloaded function
1286	/// name, this parameter is populated with the decls of the various
1287	/// overloads.
1288	bool tryExprAsCall(Expr &E, QualType &ZeroArgCallReturnTy,
1289	UnresolvedSetImpl &NonTemplateOverloads);
1290
1291	typedef OpaquePtr<DeclGroupRef> DeclGroupPtrTy;
1292	typedef OpaquePtr<TemplateName> TemplateTy;
1293	typedef OpaquePtr<QualType> TypeTy;
1294
1295	OpenCLOptions OpenCLFeatures;
1296	FPOptions CurFPFeatures;
1297
1298	const LangOptions &LangOpts;
1299	Preprocessor &PP;
1300	ASTContext &Context;
1301	ASTConsumer &Consumer;
1302	DiagnosticsEngine &Diags;
1303	SourceManager &SourceMgr;
1304	api_notes::APINotesManager APINotes;
1305
1306	/// A RAII object to enter scope of a compound statement.
1307	class CompoundScopeRAII {
1308	public:
1309	CompoundScopeRAII(Sema &S, bool IsStmtExpr = false) : S(S) {
1310	S.ActOnStartOfCompoundStmt(IsStmtExpr);
1311	}
1312
1313	~CompoundScopeRAII() { S.ActOnFinishOfCompoundStmt(); }
1314	CompoundScopeRAII(const CompoundScopeRAII &) = delete;
1315	CompoundScopeRAII &operator=(const CompoundScopeRAII &) = delete;
1316
1317	private:
1318	Sema &S;
1319	};
1320
1321	/// An RAII helper that pops function a function scope on exit.
1322	struct FunctionScopeRAII {
1323	Sema &S;
1324	bool Active;
1325	FunctionScopeRAII(Sema &S) : S(S), Active(true) {}
1326	~FunctionScopeRAII() {
1327	if (Active)
1328	S.PopFunctionScopeInfo();
1329	}
1330	void disable() { Active = false; }
1331	};
1332
1333	sema::FunctionScopeInfo getCurFunction() const* {
1334	return FunctionScopes.empty() ? nullptr : FunctionScopes.back();
1335	}
1336
1337	/// Worker object for performing CFG-based warnings.
1338	sema::AnalysisBasedWarnings AnalysisWarnings;
1339	threadSafety::BeforeSet *ThreadSafetyDeclCache;
1340
1341	/// Callback to the parser to parse templated functions when needed.
1342	typedef void LateTemplateParserCB(void *P, LateParsedTemplate &LPT);
1343	LateTemplateParserCB *LateTemplateParser;
1344	void *OpaqueParser;
1345
1346	void SetLateTemplateParser(LateTemplateParserCB LTP, void* *P) {
1347	LateTemplateParser = LTP;
1348	OpaqueParser = P;
1349	}
1350
1351	/// Callback to the parser to parse a type expressed as a string.
1352	std::function<TypeResult(StringRef, StringRef, SourceLocation)>
1353	ParseTypeFromStringCallback;
1354
1355	/// VAListTagName - The declaration name corresponding to __va_list_tag.
1356	/// This is used as part of a hack to omit that class from ADL results.
1357	DeclarationName VAListTagName;
1358
1359	/// Is the last error level diagnostic immediate. This is used to determined
1360	/// whether the next info diagnostic should be immediate.
1361	bool IsLastErrorImmediate = true;
1362
1363	/// Track if we're currently analyzing overflow behavior types in assignment
1364	/// context.
1365	bool InOverflowBehaviorAssignmentContext = false;
1366
1367	class DelayedDiagnostics;
1368
1369	class DelayedDiagnosticsState {
1370	sema::DelayedDiagnosticPool SavedPool = nullptr*;
1371	friend class Sema::DelayedDiagnostics;
1372	};
1373	typedef DelayedDiagnosticsState ParsingDeclState;
1374	typedef DelayedDiagnosticsState ProcessingContextState;
1375
1376	/// A class which encapsulates the logic for delaying diagnostics
1377	/// during parsing and other processing.
1378	class DelayedDiagnostics {
1379	/// The current pool of diagnostics into which delayed
1380	/// diagnostics should go.
1381	sema::DelayedDiagnosticPool CurPool = nullptr*;
1382
1383	public:
1384	DelayedDiagnostics() = default;
1385
1386	/// Adds a delayed diagnostic.
1387	void add(const sema::DelayedDiagnostic &diag); // in DelayedDiagnostic.h
1388
1389	/// Determines whether diagnostics should be delayed.
1390	bool shouldDelayDiagnostics() { return CurPool != nullptr; }
1391
1392	/// Returns the current delayed-diagnostics pool.
1393	sema::DelayedDiagnosticPool getCurrentPool() const* { return CurPool; }
1394
1395	/// Enter a new scope. Access and deprecation diagnostics will be
1396	/// collected in this pool.
1397	DelayedDiagnosticsState push(sema::DelayedDiagnosticPool &pool) {
1398	DelayedDiagnosticsState state;
1399	state.SavedPool = CurPool;
1400	CurPool = &pool;
1401	return state;
1402	}
1403
1404	/// Leave a delayed-diagnostic state that was previously pushed.
1405	/// Do not emit any of the diagnostics. This is performed as part
1406	/// of the bookkeeping of popping a pool "properly".
1407	void popWithoutEmitting(DelayedDiagnosticsState state) {
1408	CurPool = state.SavedPool;
1409	}
1410
1411	/// Enter a new scope where access and deprecation diagnostics are
1412	/// not delayed.
1413	DelayedDiagnosticsState pushUndelayed() {
1414	DelayedDiagnosticsState state;
1415	state.SavedPool = CurPool;
1416	CurPool = nullptr;
1417	return state;
1418	}
1419
1420	/// Undo a previous pushUndelayed().
1421	void popUndelayed(DelayedDiagnosticsState state) {
1422	assert(CurPool == nullptr);
1423	CurPool = state.SavedPool;
1424	}
1425	} DelayedDiagnostics;
1426
1427	ParsingDeclState PushParsingDeclaration(sema::DelayedDiagnosticPool &pool) {
1428	return DelayedDiagnostics.push(pool);
1429	}
1430
1431	/// Diagnostics that are emitted only if we discover that the given function
1432	/// must be codegen'ed. Because handling these correctly adds overhead to
1433	/// compilation, this is currently only enabled for CUDA compilations.
1434	SemaDiagnosticBuilder::DeferredDiagnosticsType DeviceDeferredDiags;
1435
1436	/// CurContext - This is the current declaration context of parsing.
1437	DeclContext *CurContext;
1438
1439	SemaAMDGPU &AMDGPU() {
1440	assert(AMDGPUPtr);
1441	return *AMDGPUPtr;
1442	}
1443
1444	SemaARM &ARM() {
1445	assert(ARMPtr);
1446	return *ARMPtr;
1447	}
1448
1449	SemaAVR &AVR() {
1450	assert(AVRPtr);
1451	return *AVRPtr;
1452	}
1453
1454	SemaBPF &BPF() {
1455	assert(BPFPtr);
1456	return *BPFPtr;
1457	}
1458
1459	SemaCodeCompletion &CodeCompletion() {
1460	assert(CodeCompletionPtr);
1461	return *CodeCompletionPtr;
1462	}
1463
1464	SemaCUDA &CUDA() {
1465	assert(CUDAPtr);
1466	return *CUDAPtr;
1467	}
1468
1469	SemaDirectX &DirectX() {
1470	assert(DirectXPtr);
1471	return *DirectXPtr;
1472	}
1473
1474	SemaHLSL &HLSL() {
1475	assert(HLSLPtr);
1476	return *HLSLPtr;
1477	}
1478
1479	SemaHexagon &Hexagon() {
1480	assert(HexagonPtr);
1481	return *HexagonPtr;
1482	}
1483
1484	SemaLoongArch &LoongArch() {
1485	assert(LoongArchPtr);
1486	return *LoongArchPtr;
1487	}
1488
1489	SemaM68k &M68k() {
1490	assert(M68kPtr);
1491	return *M68kPtr;
1492	}
1493
1494	SemaMIPS &MIPS() {
1495	assert(MIPSPtr);
1496	return *MIPSPtr;
1497	}
1498
1499	SemaMSP430 &MSP430() {
1500	assert(MSP430Ptr);
1501	return *MSP430Ptr;
1502	}
1503
1504	SemaNVPTX &NVPTX() {
1505	assert(NVPTXPtr);
1506	return *NVPTXPtr;
1507	}
1508
1509	SemaObjC &ObjC() {
1510	assert(ObjCPtr);
1511	return *ObjCPtr;
1512	}
1513
1514	SemaOpenACC &OpenACC() {
1515	assert(OpenACCPtr);
1516	return *OpenACCPtr;
1517	}
1518
1519	SemaOpenCL &OpenCL() {
1520	assert(OpenCLPtr);
1521	return *OpenCLPtr;
1522	}
1523
1524	SemaOpenMP &OpenMP() {
1525	assert(OpenMPPtr && "SemaOpenMP is dead");
1526	return *OpenMPPtr;
1527	}
1528
1529	SemaPPC &PPC() {
1530	assert(PPCPtr);
1531	return *PPCPtr;
1532	}
1533
1534	SemaPseudoObject &PseudoObject() {
1535	assert(PseudoObjectPtr);
1536	return *PseudoObjectPtr;
1537	}
1538
1539	SemaRISCV &RISCV() {
1540	assert(RISCVPtr);
1541	return *RISCVPtr;
1542	}
1543
1544	SemaSPIRV &SPIRV() {
1545	assert(SPIRVPtr);
1546	return *SPIRVPtr;
1547	}
1548
1549	SemaSYCL &SYCL() {
1550	assert(SYCLPtr);
1551	return *SYCLPtr;
1552	}
1553
1554	SemaSwift &Swift() {
1555	assert(SwiftPtr);
1556	return *SwiftPtr;
1557	}
1558
1559	SemaSystemZ &SystemZ() {
1560	assert(SystemZPtr);
1561	return *SystemZPtr;
1562	}
1563
1564	SemaWasm &Wasm() {
1565	assert(WasmPtr);
1566	return *WasmPtr;
1567	}
1568
1569	SemaX86 &X86() {
1570	assert(X86Ptr);
1571	return *X86Ptr;
1572	}
1573
1574	/// Source of additional semantic information.
1575	IntrusiveRefCntPtr<ExternalSemaSource> ExternalSource;
1576
1577	protected:
1578	friend class Parser;
1579	friend class InitializationSequence;
1580	friend class ASTReader;
1581	friend class ASTDeclReader;
1582	friend class ASTWriter;
1583
1584	private:
1585	std::optional<std::unique_ptr<DarwinSDKInfo>> CachedDarwinSDKInfo;
1586	bool WarnedDarwinSDKInfoMissing = false;
1587
1588	StackExhaustionHandler StackHandler;
1589
1590	Sema(const Sema &) = delete;
1591	void operator=(const Sema &) = delete;
1592
1593	/// The handler for the FileChanged preprocessor events.
1594	///
1595	/// Used for diagnostics that implement custom semantic analysis for #include
1596	/// directives, like -Wpragma-pack.
1597	sema::SemaPPCallbacks *SemaPPCallbackHandler;
1598
1599	/// The parser's current scope.
1600	///
1601	/// The parser maintains this state here.
1602	Scope *CurScope;
1603
1604	mutable IdentifierInfo *Ident_super;
1605
1606	std::unique_ptr<SemaAMDGPU> AMDGPUPtr;
1607	std::unique_ptr<SemaARM> ARMPtr;
1608	std::unique_ptr<SemaAVR> AVRPtr;
1609	std::unique_ptr<SemaBPF> BPFPtr;
1610	std::unique_ptr<SemaCodeCompletion> CodeCompletionPtr;
1611	std::unique_ptr<SemaCUDA> CUDAPtr;
1612	std::unique_ptr<SemaDirectX> DirectXPtr;
1613	std::unique_ptr<SemaHLSL> HLSLPtr;
1614	std::unique_ptr<SemaHexagon> HexagonPtr;
1615	std::unique_ptr<SemaLoongArch> LoongArchPtr;
1616	std::unique_ptr<SemaM68k> M68kPtr;
1617	std::unique_ptr<SemaMIPS> MIPSPtr;
1618	std::unique_ptr<SemaMSP430> MSP430Ptr;
1619	std::unique_ptr<SemaNVPTX> NVPTXPtr;
1620	std::unique_ptr<SemaObjC> ObjCPtr;
1621	std::unique_ptr<SemaOpenACC> OpenACCPtr;
1622	std::unique_ptr<SemaOpenCL> OpenCLPtr;
1623	std::unique_ptr<SemaOpenMP> OpenMPPtr;
1624	std::unique_ptr<SemaPPC> PPCPtr;
1625	std::unique_ptr<SemaPseudoObject> PseudoObjectPtr;
1626	std::unique_ptr<SemaRISCV> RISCVPtr;
1627	std::unique_ptr<SemaSPIRV> SPIRVPtr;
1628	std::unique_ptr<SemaSYCL> SYCLPtr;
1629	std::unique_ptr<SemaSwift> SwiftPtr;
1630	std::unique_ptr<SemaSystemZ> SystemZPtr;
1631	std::unique_ptr<SemaWasm> WasmPtr;
1632	std::unique_ptr<SemaX86> X86Ptr;
1633
1634	///@}
1635
1636	//
1637	//
1638	// -------------------------------------------------------------------------
1639	//
1640	//
1641
1642	/// \name API Notes
1643	/// Implementations are in SemaAPINotes.cpp
1644	///@{
1645
1646	public:
1647	/// Map any API notes provided for this declaration to attributes on the
1648	/// declaration.
1649	///
1650	/// Triggered by declaration-attribute processing.
1651	void ProcessAPINotes(Decl *D);
1652	/// Apply the 'Nullability:' annotation to the specified declaration
1653	void ApplyNullability(Decl *D, NullabilityKind Nullability);
1654	/// Apply the 'Type:' annotation to the specified declaration
1655	void ApplyAPINotesType(Decl *D, StringRef TypeString);
1656
1657	/// Whether APINotes should be gathered for all applicable Swift language
1658	/// versions, without being applied. Leaving clients of the current module
1659	/// to select and apply the correct version.
1660	bool captureSwiftVersionIndependentAPINotes() {
1661	return APINotes.captureVersionIndependentSwift();
1662	}
1663	///@}
1664
1665	//
1666	//
1667	// -------------------------------------------------------------------------
1668	//
1669	//
1670
1671	/// \name C++ Access Control
1672	/// Implementations are in SemaAccess.cpp
1673	///@{
1674
1675	public:
1676	enum AccessResult {
1677	AR_accessible,
1678	AR_inaccessible,
1679	AR_dependent,
1680	AR_delayed
1681	};
1682
1683	/// SetMemberAccessSpecifier - Set the access specifier of a member.
1684	/// Returns true on error (when the previous member decl access specifier
1685	/// is different from the new member decl access specifier).
1686	bool SetMemberAccessSpecifier(NamedDecl *MemberDecl,
1687	NamedDecl *PrevMemberDecl,
1688	AccessSpecifier LexicalAS);
1689
1690	/// Perform access-control checking on a previously-unresolved member
1691	/// access which has now been resolved to a member.
1692	AccessResult CheckUnresolvedMemberAccess(UnresolvedMemberExpr *E,
1693	DeclAccessPair FoundDecl);
1694	AccessResult CheckUnresolvedLookupAccess(UnresolvedLookupExpr *E,
1695	DeclAccessPair FoundDecl);
1696
1697	/// Checks access to an overloaded operator new or delete.
1698	AccessResult CheckAllocationAccess(SourceLocation OperatorLoc,
1699	SourceRange PlacementRange,
1700	CXXRecordDecl *NamingClass,
1701	DeclAccessPair FoundDecl,
1702	bool Diagnose = true);
1703
1704	/// Checks access to a constructor.
1705	AccessResult CheckConstructorAccess(SourceLocation Loc, CXXConstructorDecl *D,
1706	DeclAccessPair FoundDecl,
1707	const InitializedEntity &Entity,
1708	bool IsCopyBindingRefToTemp = false);
1709
1710	/// Checks access to a constructor.
1711	AccessResult CheckConstructorAccess(SourceLocation Loc, CXXConstructorDecl *D,
1712	DeclAccessPair FoundDecl,
1713	const InitializedEntity &Entity,
1714	const PartialDiagnostic &PDiag);
1715	AccessResult CheckDestructorAccess(SourceLocation Loc,
1716	CXXDestructorDecl *Dtor,
1717	const PartialDiagnostic &PDiag,
1718	QualType objectType = QualType ());
1719
1720	/// Checks access to the target of a friend declaration.
1721	AccessResult CheckFriendAccess(NamedDecl *D);
1722
1723	/// Checks access to a member.
1724	AccessResult CheckMemberAccess(SourceLocation UseLoc,
1725	CXXRecordDecl *NamingClass,
1726	DeclAccessPair Found);
1727
1728	/// Checks implicit access to a member in a structured binding.
1729	AccessResult
1730	CheckStructuredBindingMemberAccess(SourceLocation UseLoc,
1731	CXXRecordDecl *DecomposedClass,
1732	DeclAccessPair Field);
1733	AccessResult CheckMemberOperatorAccess(SourceLocation Loc, Expr *ObjectExpr,
1734	const SourceRange &,
1735	DeclAccessPair FoundDecl);
1736
1737	/// Checks access to an overloaded member operator, including
1738	/// conversion operators.
1739	AccessResult CheckMemberOperatorAccess(SourceLocation Loc, Expr *ObjectExpr,
1740	Expr *ArgExpr,
1741	DeclAccessPair FoundDecl);
1742	AccessResult CheckMemberOperatorAccess(SourceLocation Loc, Expr *ObjectExpr,
1743	ArrayRef<Expr *> ArgExprs,
1744	DeclAccessPair FoundDecl);
1745	AccessResult CheckAddressOfMemberAccess(Expr *OvlExpr,
1746	DeclAccessPair FoundDecl);
1747
1748	/// Checks access for a hierarchy conversion.
1749	///
1750	/// \param ForceCheck true if this check should be performed even if access
1751	/// control is disabled; some things rely on this for semantics
1752	/// \param ForceUnprivileged true if this check should proceed as if the
1753	/// context had no special privileges
1754	AccessResult CheckBaseClassAccess(SourceLocation AccessLoc, QualType Base,
1755	QualType Derived, const CXXBasePath &Path,
1756	unsigned DiagID, bool ForceCheck = false,
1757	bool ForceUnprivileged = false);
1758
1759	AccessResult CheckBaseClassAccess(
1760	SourceLocation AccessLoc, CXXRecordDecl Base, CXXRecordDecl Derived,
1761	const CXXBasePath &Path, unsigned DiagID,
1762	llvm::function_ref<void(PartialDiagnostic &PD)> SetupPDiag,
1763	bool ForceCheck = false, bool ForceUnprivileged = false);
1764
1765	/// Checks access to all the declarations in the given result set.
1766	void CheckLookupAccess(const LookupResult &R);
1767
1768	/// Checks access to Target from the given class. The check will take access
1769	/// specifiers into account, but no member access expressions and such.
1770	///
1771	/// \param Target the declaration to check if it can be accessed
1772	/// \param NamingClass the class in which the lookup was started.
1773	/// \param BaseType type of the left side of member access expression.
1774	/// \p BaseType and \p NamingClass are used for C++ access control.
1775	/// Depending on the lookup case, they should be set to the following:
1776	/// - lhs.target (member access without a qualifier):
1777	/// \p BaseType and \p NamingClass are both the type of 'lhs'.
1778	/// - lhs.X::target (member access with a qualifier):
1779	/// BaseType is the type of 'lhs', NamingClass is 'X'
1780	/// - X::target (qualified lookup without member access):
1781	/// BaseType is null, NamingClass is 'X'.
1782	/// - target (unqualified lookup).
1783	/// BaseType is null, NamingClass is the parent class of 'target'.
1784	/// \return true if the Target is accessible from the Class, false otherwise.
1785	bool IsSimplyAccessible(NamedDecl Decl, CXXRecordDecl NamingClass,
1786	QualType BaseType);
1787
1788	/// Is the given member accessible for the purposes of deciding whether to
1789	/// define a special member function as deleted?
1790	bool isMemberAccessibleForDeletion(CXXRecordDecl *NamingClass,
1791	DeclAccessPair Found, QualType ObjectType,
1792	SourceLocation Loc,
1793	const PartialDiagnostic &Diag);
1794	bool isMemberAccessibleForDeletion(CXXRecordDecl *NamingClass,
1795	DeclAccessPair Found,
1796	QualType ObjectType) {
1797	return isMemberAccessibleForDeletion(NamingClass, Found, ObjectType,
1798	Loc: SourceLocation (), Diag: PDiag());
1799	}
1800
1801	void HandleDependentAccessCheck(
1802	const DependentDiagnostic &DD,
1803	const MultiLevelTemplateArgumentList &TemplateArgs);
1804	void HandleDelayedAccessCheck(sema::DelayedDiagnostic &DD, Decl *Ctx);
1805
1806	///@}
1807
1808	//
1809	//
1810	// -------------------------------------------------------------------------
1811	//
1812	//
1813
1814	/// \name Attributes
1815	/// Implementations are in SemaAttr.cpp
1816	///@{
1817
1818	public:
1819	/// Controls member pointer representation format under the MS ABI.
1820	LangOptions::PragmaMSPointersToMembersKind
1821	MSPointerToMemberRepresentationMethod;
1822
1823	bool MSStructPragmaOn; // True when \#pragma ms_struct on
1824
1825	/// Source location for newly created implicit MSInheritanceAttrs
1826	SourceLocation ImplicitMSInheritanceAttrLoc;
1827
1828	struct PragmaClangSection {
1829	std::string SectionName;
1830	bool Valid = false;
1831	SourceLocation PragmaLocation;
1832	};
1833
1834	PragmaClangSection PragmaClangBSSSection;
1835	PragmaClangSection PragmaClangDataSection;
1836	PragmaClangSection PragmaClangRodataSection;
1837	PragmaClangSection PragmaClangRelroSection;
1838	PragmaClangSection PragmaClangTextSection;
1839
1840	enum PragmaMsStackAction {
1841	PSK_Reset = `0x0`, // #pragma ()
1842	PSK_Set = `0x1`, // #pragma (value)
1843	PSK_Push = `0x2`, // #pragma (push[, id])
1844	PSK_Pop = `0x4`, // #pragma (pop[, id])
1845	PSK_Show = `0x8`, // #pragma (show) -- only for "pack"!
1846	PSK_Push_Set = PSK_Push \| PSK_Set, // #pragma (push[, id], value)
1847	PSK_Pop_Set = PSK_Pop \| PSK_Set, // #pragma (pop[, id], value)
1848	};
1849
1850	struct PragmaPackInfo {
1851	PragmaMsStackAction Action;
1852	StringRef SlotLabel;
1853	Token Alignment;
1854	};
1855
1856	// #pragma pack and align.
1857	class AlignPackInfo {
1858	public:
1859	// `Native` represents default align mode, which may vary based on the
1860	// platform.
1861	enum Mode : unsigned char { Native, Natural, Packed, Mac68k };
1862
1863	// #pragma pack info constructor
1864	AlignPackInfo(AlignPackInfo::Mode M, unsigned Num, bool IsXL)
1865	: PackAttr(true), AlignMode(M), PackNumber(Num), XLStack(IsXL) {
1866	assert(Num == PackNumber && "The pack number has been truncated.");
1867	}
1868
1869	// #pragma align info constructor
1870	AlignPackInfo(AlignPackInfo::Mode M, bool IsXL)
1871	: PackAttr(false), AlignMode(M),
1872	PackNumber(M == Packed ? `1` : UninitPackVal), XLStack(IsXL) {}
1873
1874	explicit AlignPackInfo(bool IsXL) : AlignPackInfo (Native, IsXL) {}
1875
1876	AlignPackInfo() : AlignPackInfo (Native, false) {}
1877
1878	// When a AlignPackInfo itself cannot be used, this returns an 32-bit
1879	// integer encoding for it. This should only be passed to
1880	// AlignPackInfo::getFromRawEncoding, it should not be inspected directly.
1881	static uint32_t getRawEncoding(const AlignPackInfo &Info) {
1882	std::uint32_t Encoding{};
1883	if (Info.IsXLStack())
1884	Encoding \|= IsXLMask;
1885
1886	Encoding \|= static_cast<uint32_t>(Info.getAlignMode()) << `1`;
1887
1888	if (Info.IsPackAttr())
1889	Encoding \|= PackAttrMask;
1890
1891	Encoding \|= static_cast<uint32_t>(Info.getPackNumber()) << `4`;
1892
1893	return Encoding;
1894	}
1895
1896	static AlignPackInfo getFromRawEncoding(unsigned Encoding) {
1897	bool IsXL = static_cast<bool>(Encoding & IsXLMask);
1898	AlignPackInfo::Mode M =
1899	static_cast<AlignPackInfo::Mode>((Encoding & AlignModeMask) >> `1`);
1900	int PackNumber = (Encoding & PackNumMask) >> `4`;
1901
1902	if (Encoding & PackAttrMask)
1903	return AlignPackInfo (M, PackNumber, IsXL);
1904
1905	return AlignPackInfo (M, IsXL);
1906	}
1907
1908	bool IsPackAttr() const { return PackAttr; }
1909
1910	bool IsAlignAttr() const { return !PackAttr; }
1911
1912	Mode getAlignMode() const { return AlignMode; }
1913
1914	unsigned getPackNumber() const { return PackNumber; }
1915
1916	bool IsPackSet() const {
1917	// #pragma align, #pragma pack(), and #pragma pack(0) do not set the pack
1918	// attriute on a decl.
1919	return PackNumber != UninitPackVal && PackNumber != `0`;
1920	}
1921
1922	bool IsXLStack() const { return XLStack; }
1923
1924	bool operator==(const AlignPackInfo &Info) const {
1925	return std::tie(args: AlignMode, args: PackNumber, args: PackAttr, args: XLStack) ==
1926	std::tie(args: Info.AlignMode, args: Info.PackNumber, args: Info.PackAttr,
1927	args: Info.XLStack);
1928	}
1929
1930	bool operator!=(const AlignPackInfo &Info) const {
1931	return !(*this == Info);
1932	}
1933
1934	private:
1935	/// \brief True if this is a pragma pack attribute,
1936	/// not a pragma align attribute.
1937	bool PackAttr;
1938
1939	/// \brief The alignment mode that is in effect.
1940	Mode AlignMode;
1941
1942	/// \brief The pack number of the stack.
1943	unsigned char PackNumber;
1944
1945	/// \brief True if it is a XL #pragma align/pack stack.
1946	bool XLStack;
1947
1948	/// \brief Uninitialized pack value.
1949	static constexpr unsigned char UninitPackVal = -`1`;
1950
1951	// Masks to encode and decode an AlignPackInfo.
1952	static constexpr uint32_t IsXLMask{`0x0000'0001`};
1953	static constexpr uint32_t AlignModeMask{`0x0000'0006`};
1954	static constexpr uint32_t PackAttrMask{`0x00000'0008`};
1955	static constexpr uint32_t PackNumMask{`0x0000'01F0`};
1956	};
1957
1958	template <typename ValueType> struct PragmaStack {
1959	struct Slot {
1960	llvm::StringRef StackSlotLabel;
1961	ValueType Value;
1962	SourceLocation PragmaLocation;
1963	SourceLocation PragmaPushLocation;
1964	Slot(llvm::StringRef StackSlotLabel, ValueType Value,
1965	SourceLocation PragmaLocation, SourceLocation PragmaPushLocation)
1966	: StackSlotLabel (StackSlotLabel), Value(Value),
1967	PragmaLocation (PragmaLocation),
1968	PragmaPushLocation (PragmaPushLocation) {}
1969	};
1970
1971	void Act(SourceLocation PragmaLocation, PragmaMsStackAction Action,
1972	llvm::StringRef StackSlotLabel, ValueType Value) {
1973	if (Action == PSK_Reset) {
1974	CurrentValue = DefaultValue;
1975	CurrentPragmaLocation = PragmaLocation;
1976	return;
1977	}
1978	if (Action & PSK_Push)
1979	Stack.emplace_back(StackSlotLabel, CurrentValue, CurrentPragmaLocation,
1980	PragmaLocation);
1981	else if (Action & PSK_Pop) {
1982	if (!StackSlotLabel.empty()) {
1983	// If we've got a label, try to find it and jump there.
1984	auto I = llvm::find_if(llvm::reverse(Stack), [&](const Slot &x) {
1985	return x.StackSlotLabel == StackSlotLabel;
1986	});
1987	// If we found the label so pop from there.
1988	if (I != Stack.rend()) {
1989	CurrentValue = I->Value;
1990	CurrentPragmaLocation = I->PragmaLocation;
1991	Stack.erase(std::prev(I.base()), Stack.end());
1992	}
1993	} else if (!Stack.empty()) {
1994	// We do not have a label, just pop the last entry.
1995	CurrentValue = Stack.back().Value;
1996	CurrentPragmaLocation = Stack.back().PragmaLocation;
1997	Stack.pop_back();
1998	}
1999	}
2000	if (Action & PSK_Set) {
2001	CurrentValue = Value;
2002	CurrentPragmaLocation = PragmaLocation;
2003	}
2004	}
2005
2006	// MSVC seems to add artificial slots to #pragma stacks on entering a C++
2007	// method body to restore the stacks on exit, so it works like this:
2008	//
2009	// struct S {
2010	// #pragma <name>(push, InternalPragmaSlot, <current_pragma_value>)
2011	// void Method {}
2012	// #pragma <name>(pop, InternalPragmaSlot)
2013	// };
2014	//
2015	// It works even with #pragma vtordisp, although MSVC doesn't support
2016	// #pragma vtordisp(push [, id], n)
2017	// syntax.
2018	//
2019	// Push / pop a named sentinel slot.
2020	void SentinelAction(PragmaMsStackAction Action, StringRef Label) {
2021	assert((Action == PSK_Push \|\| Action == PSK_Pop) &&
2022	"Can only push / pop #pragma stack sentinels!");
2023	Act(PragmaLocation: CurrentPragmaLocation, Action, StackSlotLabel: Label, Value: CurrentValue);
2024	}
2025
2026	// Constructors.
2027	explicit PragmaStack(const ValueType &Default)
2028	: DefaultValue(Default), CurrentValue(Default) {}
2029
2030	bool hasValue() const { return CurrentValue != DefaultValue; }
2031
2032	SmallVector<Slot, `2`> Stack;
2033	ValueType DefaultValue; // Value used for PSK_Reset action.
2034	ValueType CurrentValue;
2035	SourceLocation CurrentPragmaLocation;
2036	};
2037	// FIXME: We should serialize / deserialize these if they occur in a PCH (but
2038	// we shouldn't do so if they're in a module).
2039
2040	/// Whether to insert vtordisps prior to virtual bases in the Microsoft
2041	/// C++ ABI. Possible values are 0, 1, and 2, which mean:
2042	///
2043	/// 0: Suppress all vtordisps
2044	/// 1: Insert vtordisps in the presence of vbase overrides and non-trivial
2045	/// structors
2046	/// 2: Always insert vtordisps to support RTTI on partially constructed
2047	/// objects
2048	PragmaStack<MSVtorDispMode> VtorDispStack;
2049	PragmaStack<AlignPackInfo> AlignPackStack;
2050	// The current #pragma align/pack values and locations at each #include.
2051	struct AlignPackIncludeState {
2052	AlignPackInfo CurrentValue;
2053	SourceLocation CurrentPragmaLocation;
2054	bool HasNonDefaultValue, ShouldWarnOnInclude;
2055	};
2056	SmallVector<AlignPackIncludeState, `8`> AlignPackIncludeStack;
2057	// Segment #pragmas.
2058	PragmaStack<StringLiteral *> DataSegStack;
2059	PragmaStack<StringLiteral *> BSSSegStack;
2060	PragmaStack<StringLiteral *> ConstSegStack;
2061	PragmaStack<StringLiteral *> CodeSegStack;
2062
2063	// #pragma strict_gs_check.
2064	PragmaStack<bool> StrictGuardStackCheckStack;
2065
2066	// This stack tracks the current state of Sema.CurFPFeatures.
2067	PragmaStack<FPOptionsOverride> FpPragmaStack;
2068	FPOptionsOverride CurFPFeatureOverrides() {
2069	FPOptionsOverride result;
2070	if (!FpPragmaStack.hasValue()) {
2071	result = FPOptionsOverride ();
2072	} else {
2073	result = FpPragmaStack.CurrentValue;
2074	}
2075	return result;
2076	}
2077
2078	enum PragmaSectionKind {
2079	PSK_DataSeg,
2080	PSK_BSSSeg,
2081	PSK_ConstSeg,
2082	PSK_CodeSeg,
2083	};
2084
2085	// RAII object to push / pop sentinel slots for all MS #pragma stacks.
2086	// Actions should be performed only if we enter / exit a C++ method body.
2087	class PragmaStackSentinelRAII {
2088	public:
2089	PragmaStackSentinelRAII(Sema &S, StringRef SlotLabel, bool ShouldAct);
2090	~PragmaStackSentinelRAII();
2091	PragmaStackSentinelRAII(const PragmaStackSentinelRAII &) = delete;
2092	PragmaStackSentinelRAII &
2093	operator=(const PragmaStackSentinelRAII &) = delete;
2094
2095	private:
2096	Sema &S;
2097	StringRef SlotLabel;
2098	bool ShouldAct;
2099	};
2100
2101	/// Last section used with #pragma init_seg.
2102	StringLiteral *CurInitSeg;
2103	SourceLocation CurInitSegLoc;
2104
2105	/// Sections used with #pragma alloc_text.
2106	llvm::StringMap<std::tuple<StringRef, SourceLocation>> FunctionToSectionMap;
2107
2108	/// VisContext - Manages the stack for \#pragma GCC visibility.
2109	void VisContext; // Really a "PragmaVisStack"
2110
2111	/// This an attribute introduced by \#pragma clang attribute.
2112	struct PragmaAttributeEntry {
2113	SourceLocation Loc;
2114	ParsedAttr *Attribute;
2115	SmallVector<attr::SubjectMatchRule, `4`> MatchRules;
2116	bool IsUsed;
2117	};
2118
2119	/// A push'd group of PragmaAttributeEntries.
2120	struct PragmaAttributeGroup {
2121	/// The location of the push attribute.
2122	SourceLocation Loc;
2123	/// The namespace of this push group.
2124	const IdentifierInfo *Namespace;
2125	SmallVector<PragmaAttributeEntry, `2`> Entries;
2126	};
2127
2128	SmallVector<PragmaAttributeGroup, `2`> PragmaAttributeStack;
2129
2130	/// The declaration that is currently receiving an attribute from the
2131	/// #pragma attribute stack.
2132	const Decl *PragmaAttributeCurrentTargetDecl;
2133
2134	/// This represents the last location of a "#pragma clang optimize off"
2135	/// directive if such a directive has not been closed by an "on" yet. If
2136	/// optimizations are currently "on", this is set to an invalid location.
2137	SourceLocation OptimizeOffPragmaLocation;
2138
2139	/// Get the location for the currently active "\#pragma clang optimize
2140	/// off". If this location is invalid, then the state of the pragma is "on".
2141	SourceLocation getOptimizeOffPragmaLocation() const {
2142	return OptimizeOffPragmaLocation;
2143	}
2144
2145	/// The "on" or "off" argument passed by \#pragma optimize, that denotes
2146	/// whether the optimizations in the list passed to the pragma should be
2147	/// turned off or on. This boolean is true by default because command line
2148	/// options are honored when `#pragma optimize("", on)`.
2149	/// (i.e. `ModifyFnAttributeMSPragmaOptimze()` does nothing)
2150	bool MSPragmaOptimizeIsOn = true;
2151
2152	/// Set of no-builtin functions listed by \#pragma function.
2153	llvm::SmallSetVector<StringRef, `4`> MSFunctionNoBuiltins;
2154
2155	/// AddAlignmentAttributesForRecord - Adds any needed alignment attributes to
2156	/// a the record decl, to handle '\#pragma pack' and '\#pragma options align'.
2157	void AddAlignmentAttributesForRecord(RecordDecl *RD);
2158
2159	/// AddMsStructLayoutForRecord - Adds ms_struct layout attribute to record.
2160	void AddMsStructLayoutForRecord(RecordDecl *RD);
2161
2162	/// Add gsl::Pointer attribute to std::container::iterator
2163	/// \param ND The declaration that introduces the name
2164	/// std::container::iterator. \param UnderlyingRecord The record named by ND.
2165	void inferGslPointerAttribute(NamedDecl ND, CXXRecordDecl UnderlyingRecord);
2166
2167	/// Add [[gsl::Owner]] and [[gsl::Pointer]] attributes for std:: types.
2168	void inferGslOwnerPointerAttribute(CXXRecordDecl *Record);
2169
2170	/// Add [[clang:::lifetimebound]] attr for std:: functions and methods.
2171	void inferLifetimeBoundAttribute(FunctionDecl *FD);
2172
2173	/// Add [[clang:::lifetime_capture_by(this)]] to STL container methods.
2174	void inferLifetimeCaptureByAttribute(FunctionDecl *FD);
2175
2176	/// Add [[gsl::Pointer]] attributes for std:: types.
2177	void inferGslPointerAttribute(TypedefNameDecl *TD);
2178
2179	LifetimeCaptureByAttr ParseLifetimeCaptureByAttr(const* ParsedAttr &AL,
2180	StringRef ParamName);
2181	// Processes the argument 'X' in [[clang::lifetime_capture_by(X)]]. Since 'X'
2182	// can be the name of a function parameter, we need to parse the function
2183	// declaration and rest of the parameters before processesing 'X'. Therefore
2184	// do this lazily instead of processing while parsing the annotation itself.
2185	void LazyProcessLifetimeCaptureByParams(FunctionDecl *FD);
2186
2187	/// Add _Nullable attributes for std:: types.
2188	void inferNullableClassAttribute(CXXRecordDecl *CRD);
2189
2190	/// ActOnPragmaClangSection - Called on well formed \#pragma clang section
2191	void ActOnPragmaClangSection(SourceLocation PragmaLoc,
2192	PragmaClangSectionAction Action,
2193	PragmaClangSectionKind SecKind,
2194	StringRef SecName);
2195
2196	/// ActOnPragmaOptionsAlign - Called on well formed \#pragma options align.
2197	void ActOnPragmaOptionsAlign(PragmaOptionsAlignKind Kind,
2198	SourceLocation PragmaLoc);
2199
2200	/// ActOnPragmaPack - Called on well formed \#pragma pack(...).
2201	void ActOnPragmaPack(SourceLocation PragmaLoc, PragmaMsStackAction Action,
2202	StringRef SlotLabel, Expr *Alignment);
2203
2204	/// ConstantFoldAttrArgs - Folds attribute arguments into ConstantExprs
2205	/// (unless they are value dependent or type dependent). Returns false
2206	/// and emits a diagnostic if one or more of the arguments could not be
2207	/// folded into a constant.
2208	bool ConstantFoldAttrArgs(const AttributeCommonInfo &CI,
2209	MutableArrayRef<Expr *> Args);
2210
2211	enum class PragmaAlignPackDiagnoseKind {
2212	NonDefaultStateAtInclude,
2213	ChangedStateAtExit
2214	};
2215
2216	void DiagnoseNonDefaultPragmaAlignPack(PragmaAlignPackDiagnoseKind Kind,
2217	SourceLocation IncludeLoc);
2218	void DiagnoseUnterminatedPragmaAlignPack();
2219
2220	/// ActOnPragmaMSStruct - Called on well formed \#pragma ms_struct [on\|off].
2221	void ActOnPragmaMSStruct(PragmaMSStructKind Kind);
2222
2223	/// ActOnPragmaMSComment - Called on well formed
2224	/// \#pragma comment(kind, "arg").
2225	void ActOnPragmaMSComment(SourceLocation CommentLoc, PragmaMSCommentKind Kind,
2226	StringRef Arg);
2227
2228	/// ActOnPragmaDetectMismatch - Call on well-formed \#pragma detect_mismatch
2229	void ActOnPragmaDetectMismatch(SourceLocation Loc, StringRef Name,
2230	StringRef Value);
2231
2232	/// Are precise floating point semantics currently enabled?
2233	bool isPreciseFPEnabled() {
2234	return !CurFPFeatures.getAllowFPReassociate() &&
2235	!CurFPFeatures.getNoSignedZero() &&
2236	!CurFPFeatures.getAllowReciprocal() &&
2237	!CurFPFeatures.getAllowApproxFunc();
2238	}
2239
2240	void ActOnPragmaFPEvalMethod(SourceLocation Loc,
2241	LangOptions::FPEvalMethodKind Value);
2242
2243	/// ActOnPragmaFloatControl - Call on well-formed \#pragma float_control
2244	void ActOnPragmaFloatControl(SourceLocation Loc, PragmaMsStackAction Action,
2245	PragmaFloatControlKind Value);
2246
2247	/// ActOnPragmaMSPointersToMembers - called on well formed \#pragma
2248	/// pointers_to_members(representation method[, general purpose
2249	/// representation]).
2250	void ActOnPragmaMSPointersToMembers(
2251	LangOptions::PragmaMSPointersToMembersKind Kind,
2252	SourceLocation PragmaLoc);
2253
2254	/// Called on well formed \#pragma vtordisp().
2255	void ActOnPragmaMSVtorDisp(PragmaMsStackAction Action,
2256	SourceLocation PragmaLoc, MSVtorDispMode Value);
2257
2258	bool UnifySection(StringRef SectionName, int SectionFlags,
2259	NamedDecl *TheDecl);
2260	bool UnifySection(StringRef SectionName, int SectionFlags,
2261	SourceLocation PragmaSectionLocation);
2262
2263	/// Called on well formed \#pragma bss_seg/data_seg/const_seg/code_seg.
2264	void ActOnPragmaMSSeg(SourceLocation PragmaLocation,
2265	PragmaMsStackAction Action,
2266	llvm::StringRef StackSlotLabel,
2267	StringLiteral *SegmentName, llvm::StringRef PragmaName);
2268
2269	/// Called on well formed \#pragma section().
2270	void ActOnPragmaMSSection(SourceLocation PragmaLocation, int SectionFlags,
2271	StringLiteral *SegmentName);
2272
2273	/// Called on well-formed \#pragma init_seg().
2274	void ActOnPragmaMSInitSeg(SourceLocation PragmaLocation,
2275	StringLiteral *SegmentName);
2276
2277	/// Called on well-formed \#pragma alloc_text().
2278	void ActOnPragmaMSAllocText(
2279	SourceLocation PragmaLocation, StringRef Section,
2280	const SmallVector<std::tuple<IdentifierInfo *, SourceLocation>>
2281	&Functions);
2282
2283	/// ActOnPragmaMSStrictGuardStackCheck - Called on well formed \#pragma
2284	/// strict_gs_check.
2285	void ActOnPragmaMSStrictGuardStackCheck(SourceLocation PragmaLocation,
2286	PragmaMsStackAction Action,
2287	bool Value);
2288
2289	/// ActOnPragmaUnused - Called on well-formed '\#pragma unused'.
2290	void ActOnPragmaUnused(const Token &Identifier, Scope *curScope,
2291	SourceLocation PragmaLoc);
2292
2293	void ActOnPragmaAttributeAttribute(ParsedAttr &Attribute,
2294	SourceLocation PragmaLoc,
2295	attr::ParsedSubjectMatchRuleSet Rules);
2296	void ActOnPragmaAttributeEmptyPush(SourceLocation PragmaLoc,
2297	const IdentifierInfo *Namespace);
2298
2299	/// Called on well-formed '\#pragma clang attribute pop'.
2300	void ActOnPragmaAttributePop(SourceLocation PragmaLoc,
2301	const IdentifierInfo *Namespace);
2302
2303	/// Adds the attributes that have been specified using the
2304	/// '\#pragma clang attribute push' directives to the given declaration.
2305	void AddPragmaAttributes(Scope S, Decl D);
2306
2307	using InstantiationContextDiagFuncRef =
2308	llvm::function_ref<void(SourceLocation, PartialDiagnostic)>;
2309	auto getDefaultDiagFunc() {
2310	return [this](SourceLocation Loc, PartialDiagnostic PD) {
2311	// This bypasses a lot of the filters in the diag engine, as it's
2312	// to be used to attach notes to diagnostics which have already
2313	// been filtered through.
2314	DiagnosticBuilder Builder(Diags.Report(Loc, DiagID: PD.getDiagID()));
2315	PD.Emit(DB: Builder);
2316	};
2317	}
2318
2319	void PrintPragmaAttributeInstantiationPoint(
2320	InstantiationContextDiagFuncRef DiagFunc);
2321	void PrintPragmaAttributeInstantiationPoint() {
2322	PrintPragmaAttributeInstantiationPoint(DiagFunc: getDefaultDiagFunc());
2323	}
2324
2325	void DiagnoseUnterminatedPragmaAttribute();
2326
2327	/// Called on well formed \#pragma clang optimize.
2328	void ActOnPragmaOptimize(bool On, SourceLocation PragmaLoc);
2329
2330	/// #pragma optimize("[optimization-list]", on \| off).
2331	void ActOnPragmaMSOptimize(SourceLocation Loc, bool IsOn);
2332
2333	/// Call on well formed \#pragma function.
2334	void
2335	ActOnPragmaMSFunction(SourceLocation Loc,
2336	const llvm::SmallVectorImpl<StringRef> &NoBuiltins);
2337
2338	NamedDecl lookupExternCFunctionOrVariable(IdentifierInfo IdentId,
2339	SourceLocation NameLoc,
2340	Scope *curScope);
2341
2342	/// Information from a C++ #pragma export, for a symbol that we
2343	/// haven't seen the declaration for yet.
2344	struct PendingPragmaInfo {
2345	SourceLocation NameLoc;
2346	bool Used;
2347	};
2348
2349	llvm::DenseMap<IdentifierInfo *, PendingPragmaInfo> PendingExportedNames;
2350
2351	/// ActonPragmaExport - called on well-formed '\#pragma export'.
2352	void ActOnPragmaExport(IdentifierInfo *IdentId, SourceLocation ExportNameLoc,
2353	Scope *curScope);
2354
2355	/// Only called on function definitions; if there is a pragma in scope
2356	/// with the effect of a range-based optnone, consider marking the function
2357	/// with attribute optnone.
2358	void AddRangeBasedOptnone(FunctionDecl *FD);
2359
2360	/// Only called on function definitions; if there is a `#pragma alloc_text`
2361	/// that decides which code section the function should be in, add
2362	/// attribute section to the function.
2363	void AddSectionMSAllocText(FunctionDecl *FD);
2364
2365	/// Adds the 'optnone' attribute to the function declaration if there
2366	/// are no conflicts; Loc represents the location causing the 'optnone'
2367	/// attribute to be added (usually because of a pragma).
2368	void AddOptnoneAttributeIfNoConflicts(FunctionDecl *FD, SourceLocation Loc);
2369
2370	/// Only called on function definitions; if there is a MSVC #pragma optimize
2371	/// in scope, consider changing the function's attributes based on the
2372	/// optimization list passed to the pragma.
2373	void ModifyFnAttributesMSPragmaOptimize(FunctionDecl *FD);
2374
2375	/// Only called on function definitions; if there is a pragma in scope
2376	/// with the effect of a range-based no_builtin, consider marking the function
2377	/// with attribute no_builtin.
2378	void AddImplicitMSFunctionNoBuiltinAttr(FunctionDecl *FD);
2379
2380	/// AddPushedVisibilityAttribute - If '\#pragma GCC visibility' was used,
2381	/// add an appropriate visibility attribute.
2382	void AddPushedVisibilityAttribute(Decl *RD);
2383
2384	/// FreeVisContext - Deallocate and null out VisContext.
2385	void FreeVisContext();
2386
2387	/// ActOnPragmaVisibility - Called on well formed \#pragma GCC visibility... .
2388	void ActOnPragmaVisibility(const IdentifierInfo *VisType,
2389	SourceLocation PragmaLoc);
2390
2391	/// ActOnPragmaFPContract - Called on well formed
2392	/// \#pragma {STDC,OPENCL} FP_CONTRACT and
2393	/// \#pragma clang fp contract
2394	void ActOnPragmaFPContract(SourceLocation Loc, LangOptions::FPModeKind FPC);
2395
2396	/// Called on well formed
2397	/// \#pragma clang fp reassociate
2398	/// or
2399	/// \#pragma clang fp reciprocal
2400	void ActOnPragmaFPValueChangingOption(SourceLocation Loc, PragmaFPKind Kind,
2401	bool IsEnabled);
2402
2403	/// ActOnPragmaFenvAccess - Called on well formed
2404	/// \#pragma STDC FENV_ACCESS
2405	void ActOnPragmaFEnvAccess(SourceLocation Loc, bool IsEnabled);
2406
2407	/// ActOnPragmaCXLimitedRange - Called on well formed
2408	/// \#pragma STDC CX_LIMITED_RANGE
2409	void ActOnPragmaCXLimitedRange(SourceLocation Loc,
2410	LangOptions::ComplexRangeKind Range);
2411
2412	/// Called on well formed '\#pragma clang fp' that has option 'exceptions'.
2413	void ActOnPragmaFPExceptions(SourceLocation Loc,
2414	LangOptions::FPExceptionModeKind);
2415
2416	/// Called to set constant rounding mode for floating point operations.
2417	void ActOnPragmaFEnvRound(SourceLocation Loc, llvm::RoundingMode);
2418
2419	/// Called to set exception behavior for floating point operations.
2420	void setExceptionMode(SourceLocation Loc, LangOptions::FPExceptionModeKind);
2421
2422	/// PushNamespaceVisibilityAttr - Note that we've entered a
2423	/// namespace with a visibility attribute.
2424	void PushNamespaceVisibilityAttr(const VisibilityAttr *Attr,
2425	SourceLocation Loc);
2426
2427	/// PopPragmaVisibility - Pop the top element of the visibility stack; used
2428	/// for '\#pragma GCC visibility' and visibility attributes on namespaces.
2429	void PopPragmaVisibility(bool IsNamespaceEnd, SourceLocation EndLoc);
2430
2431	/// Handles semantic checking for features that are common to all attributes,
2432	/// such as checking whether a parameter was properly specified, or the
2433	/// correct number of arguments were passed, etc. Returns true if the
2434	/// attribute has been diagnosed.
2435	bool checkCommonAttributeFeatures(const Decl D, const* ParsedAttr &A,
2436	bool SkipArgCountCheck = false);
2437	bool checkCommonAttributeFeatures(const Stmt S, const* ParsedAttr &A,
2438	bool SkipArgCountCheck = false);
2439
2440	///@}
2441
2442	//
2443	//
2444	// -------------------------------------------------------------------------
2445	//
2446	//
2447
2448	/// \name Availability Attribute Handling
2449	/// Implementations are in SemaAvailability.cpp
2450	///@{
2451
2452	public:
2453	/// Issue any -Wunguarded-availability warnings in \c FD
2454	void DiagnoseUnguardedAvailabilityViolations(Decl *FD);
2455
2456	void handleDelayedAvailabilityCheck(sema::DelayedDiagnostic &DD, Decl *Ctx);
2457
2458	/// Retrieve the current function, if any, that should be analyzed for
2459	/// potential availability violations.
2460	sema::FunctionScopeInfo *getCurFunctionAvailabilityContext();
2461
2462	void DiagnoseAvailabilityOfDecl(NamedDecl *D, ArrayRef<SourceLocation> Locs,
2463	const ObjCInterfaceDecl *UnknownObjCClass,
2464	bool ObjCPropertyAccess,
2465	bool AvoidPartialAvailabilityChecks,
2466	ObjCInterfaceDecl *ClassReceiver);
2467
2468	void DiagnoseAvailabilityOfDecl(NamedDecl *D, ArrayRef<SourceLocation> Locs);
2469
2470	std::pair<AvailabilityResult, const NamedDecl *>
2471	ShouldDiagnoseAvailabilityOfDecl(const NamedDecl D, std::string Message,
2472	ObjCInterfaceDecl *ClassReceiver);
2473	///@}
2474
2475	//
2476	//
2477	// -------------------------------------------------------------------------
2478	//
2479	//
2480
2481	/// \name Bounds Safety
2482	/// Implementations are in SemaBoundsSafety.cpp
2483	///@{
2484	public:
2485	/// Check if applying the specified attribute variant from the "counted by"
2486	/// family of attributes to FieldDecl \p FD is semantically valid. If
2487	/// semantically invalid diagnostics will be emitted explaining the problems.
2488	///
2489	/// \param FD The FieldDecl to apply the attribute to
2490	/// \param E The count expression on the attribute
2491	/// \param CountInBytes If true the attribute is from the "sized_by" family of
2492	/// attributes. If the false the attribute is from
2493	/// "counted_by" family of attributes.
2494	/// \param OrNull If true the attribute is from the "_or_null" suffixed family
2495	/// of attributes. If false the attribute does not have the
2496	/// suffix.
2497	///
2498	/// Together \p CountInBytes and \p OrNull decide the attribute variant. E.g.
2499	/// \p CountInBytes and \p OrNull both being true indicates the
2500	/// `counted_by_or_null` attribute.
2501	///
2502	/// \returns false iff semantically valid.
2503	bool CheckCountedByAttrOnField(FieldDecl FD, Expr E, bool CountInBytes,
2504	bool OrNull);
2505
2506	/// Perform Bounds Safety Semantic checks for assigning to a `__counted_by` or
2507	/// `__counted_by_or_null` pointer type \param LHSTy.
2508	///
2509	/// \param LHSTy The type being assigned to. Checks will only be performed if
2510	/// the type is a `counted_by` or `counted_by_or_null ` pointer.
2511	/// \param RHSExpr The expression being assigned from.
2512	/// \param Action The type assignment being performed
2513	/// \param Loc The SourceLocation to use for error diagnostics
2514	/// \param Assignee The ValueDecl being assigned. This is used to compute
2515	/// the name of the assignee. If the assignee isn't known this can
2516	/// be set to nullptr.
2517	/// \param ShowFullyQualifiedAssigneeName If set to true when using \p
2518	/// Assignee to compute the name of the assignee use the fully
2519	/// qualified name, otherwise use the unqualified name.
2520	///
2521	/// \returns True iff no diagnostic where emitted, false otherwise.
2522	bool BoundsSafetyCheckAssignmentToCountAttrPtr(
2523	QualType LHSTy, Expr *RHSExpr, AssignmentAction Action,
2524	SourceLocation Loc, const ValueDecl *Assignee,
2525	bool ShowFullyQualifiedAssigneeName);
2526
2527	/// Perform Bounds Safety Semantic checks for initializing a Bounds Safety
2528	/// pointer.
2529	///
2530	/// \param Entity The entity being initialized
2531	/// \param Kind The kind of initialization being performed
2532	/// \param Action The type assignment being performed
2533	/// \param LHSTy The type being assigned to. Checks will only be performed if
2534	/// the type is a `counted_by` or `counted_by_or_null ` pointer.
2535	/// \param RHSExpr The expression being used for initialization.
2536	///
2537	/// \returns True iff no diagnostic where emitted, false otherwise.
2538	bool BoundsSafetyCheckInitialization(const InitializedEntity &Entity,
2539	const InitializationKind &Kind,
2540	AssignmentAction Action,
2541	QualType LHSType, Expr *RHSExpr);
2542
2543	/// Perform Bounds Safety semantic checks for uses of invalid uses counted_by
2544	/// or counted_by_or_null pointers in \param E.
2545	///
2546	/// \param E the expression to check
2547	///
2548	/// \returns True iff no diagnostic where emitted, false otherwise.
2549	bool BoundsSafetyCheckUseOfCountAttrPtr(const Expr *E);
2550	///@}
2551
2552	//
2553	//
2554	// -------------------------------------------------------------------------
2555	//
2556	//
2557
2558	/// \name Casts
2559	/// Implementations are in SemaCast.cpp
2560	///@{
2561
2562	public:
2563	static bool isCast(CheckedConversionKind CCK) {
2564	return CCK == CheckedConversionKind::CStyleCast \|\|
2565	CCK == CheckedConversionKind::FunctionalCast \|\|
2566	CCK == CheckedConversionKind::OtherCast;
2567	}
2568
2569	/// ActOnCXXNamedCast - Parse
2570	/// {dynamic,static,reinterpret,const,addrspace}_cast's.
2571	ExprResult ActOnCXXNamedCast(SourceLocation OpLoc, tok::TokenKind Kind,
2572	SourceLocation LAngleBracketLoc, Declarator &D,
2573	SourceLocation RAngleBracketLoc,
2574	SourceLocation LParenLoc, Expr *E,
2575	SourceLocation RParenLoc);
2576
2577	ExprResult BuildCXXNamedCast(SourceLocation OpLoc, tok::TokenKind Kind,
2578	TypeSourceInfo Ty, Expr E,
2579	SourceRange AngleBrackets, SourceRange Parens);
2580
2581	ExprResult ActOnBuiltinBitCastExpr(SourceLocation KWLoc, Declarator &Dcl,
2582	ExprResult Operand,
2583	SourceLocation RParenLoc);
2584
2585	ExprResult BuildBuiltinBitCastExpr(SourceLocation KWLoc, TypeSourceInfo *TSI,
2586	Expr *Operand, SourceLocation RParenLoc);
2587
2588	// Checks that reinterpret casts don't have undefined behavior.
2589	void CheckCompatibleReinterpretCast(QualType SrcType, QualType DestType,
2590	bool IsDereference, SourceRange Range);
2591
2592	// Checks that the vector type should be initialized from a scalar
2593	// by splatting the value rather than populating a single element.
2594	// This is the case for AltiVecVector types as well as with
2595	// AltiVecPixel and AltiVecBool when -faltivec-src-compat=xl is specified.
2596	bool ShouldSplatAltivecScalarInCast(const VectorType *VecTy);
2597
2598	// Checks if the -faltivec-src-compat=gcc option is specified.
2599	// If so, AltiVecVector, AltiVecBool and AltiVecPixel types are
2600	// treated the same way as they are when trying to initialize
2601	// these vectors on gcc (an error is emitted).
2602	bool CheckAltivecInitFromScalar(SourceRange R, QualType VecTy,
2603	QualType SrcTy);
2604
2605	ExprResult BuildCStyleCastExpr(SourceLocation LParenLoc, TypeSourceInfo *Ty,
2606	SourceLocation RParenLoc, Expr *Op);
2607
2608	ExprResult BuildCXXFunctionalCastExpr(TypeSourceInfo *TInfo, QualType Type,
2609	SourceLocation LParenLoc,
2610	Expr *CastExpr,
2611	SourceLocation RParenLoc);
2612
2613	///@}
2614
2615	//
2616	//
2617	// -------------------------------------------------------------------------
2618	//
2619	//
2620
2621	/// \name Extra Semantic Checking
2622	/// Implementations are in SemaChecking.cpp
2623	///@{
2624
2625	public:
2626	/// Used to change context to isConstantEvaluated without pushing a heavy
2627	/// ExpressionEvaluationContextRecord object.
2628	bool isConstantEvaluatedOverride = false;
2629
2630	bool isConstantEvaluatedContext() const {
2631	return currentEvaluationContext().isConstantEvaluated() \|\|
2632	isConstantEvaluatedOverride;
2633	}
2634
2635	SourceLocation getLocationOfStringLiteralByte(const StringLiteral *SL,
2636	unsigned ByteNo) const;
2637
2638	enum FormatArgumentPassingKind {
2639	FAPK_Fixed, // values to format are fixed (no C-style variadic arguments)
2640	FAPK_Variadic, // values to format are passed as variadic arguments
2641	FAPK_VAList, // values to format are passed in a va_list
2642	FAPK_Elsewhere, // values to format are not passed to this function
2643	};
2644
2645	// Used to grab the relevant information from a FormatAttr and a
2646	// FunctionDeclaration.
2647	struct FormatStringInfo {
2648	unsigned FormatIdx;
2649	unsigned FirstDataArg;
2650	FormatArgumentPassingKind ArgPassingKind;
2651	};
2652
2653	/// Given a function and its FormatAttr or FormatMatchesAttr info, attempts to
2654	/// populate the FormatStringInfo parameter with the attribute's correct
2655	/// format_idx and firstDataArg. Returns true when the format fits the
2656	/// function and the FormatStringInfo has been populated.
2657	static bool getFormatStringInfo(const Decl Function, unsigned* FormatIdx,
2658	unsigned FirstArg, FormatStringInfo *FSI);
2659	static bool getFormatStringInfo(unsigned FormatIdx, unsigned FirstArg,
2660	bool HasImplicitThisParam, bool IsVariadic,
2661	FormatStringInfo *FSI);
2662
2663	// Used by C++ template instantiation.
2664	ExprResult BuiltinShuffleVector(CallExpr *TheCall);
2665
2666	/// ConvertVectorExpr - Handle __builtin_convertvector
2667	ExprResult ConvertVectorExpr(Expr E, TypeSourceInfo TInfo,
2668	SourceLocation BuiltinLoc,
2669	SourceLocation RParenLoc);
2670
2671	static StringRef GetFormatStringTypeName(FormatStringType FST);
2672	static FormatStringType GetFormatStringType(StringRef FormatFlavor);
2673	static FormatStringType GetFormatStringType(const FormatAttr *Format);
2674	static FormatStringType GetFormatStringType(const FormatMatchesAttr *Format);
2675
2676	bool FormatStringHasSArg(const StringLiteral *FExpr);
2677
2678	/// Check for comparisons of floating-point values using == and !=. Issue a
2679	/// warning if the comparison is not likely to do what the programmer
2680	/// intended.
2681	void CheckFloatComparison(SourceLocation Loc, const Expr *LHS,
2682	const Expr *RHS, BinaryOperatorKind Opcode);
2683
2684	/// Register a magic integral constant to be used as a type tag.
2685	void RegisterTypeTagForDatatype(const IdentifierInfo *ArgumentKind,
2686	uint64_t MagicValue, QualType Type,
2687	bool LayoutCompatible, bool MustBeNull);
2688
2689	struct TypeTagData {
2690	TypeTagData() {}
2691
2692	TypeTagData(QualType Type, bool LayoutCompatible, bool MustBeNull)
2693	: Type (Type), LayoutCompatible(LayoutCompatible),
2694	MustBeNull(MustBeNull) {}
2695
2696	QualType Type;
2697
2698	/// If true, \c Type should be compared with other expression's types for
2699	/// layout-compatibility.
2700	LLVM_PREFERRED_TYPE(bool)
2701	unsigned LayoutCompatible : `1`;
2702	LLVM_PREFERRED_TYPE(bool)
2703	unsigned MustBeNull : `1`;
2704	};
2705
2706	/// A pair of ArgumentKind identifier and magic value. This uniquely
2707	/// identifies the magic value.
2708	typedef std::pair<const IdentifierInfo *, uint64_t> TypeTagMagicValue;
2709
2710	/// Diagnoses the current set of gathered accesses. This happens at the end of
2711	/// each expression evaluation context. Diagnostics are emitted only for
2712	/// accesses gathered in the current evaluation context.
2713	void DiagnoseMisalignedMembers();
2714
2715	/// This function checks if the expression is in the sef of potentially
2716	/// misaligned members and it is converted to some pointer type T with lower
2717	/// or equal alignment requirements. If so it removes it. This is used when
2718	/// we do not want to diagnose such misaligned access (e.g. in conversions to
2719	/// void).*
2720	void DiscardMisalignedMemberAddress(const Type T, Expr E);
2721
2722	/// Returns true if `From` is a function or pointer to a function with the
2723	/// `cfi_unchecked_callee` attribute but `To` is a function or pointer to
2724	/// function without this attribute.
2725	bool DiscardingCFIUncheckedCallee(QualType From, QualType To) const;
2726
2727	/// This function calls Action when it determines that E designates a
2728	/// misaligned member due to the packed attribute. This is used to emit
2729	/// local diagnostics like in reference binding.
2730	void RefersToMemberWithReducedAlignment(
2731	Expr *E,
2732	llvm::function_ref<void(Expr , RecordDecl , FieldDecl *, CharUnits)>
2733	Action);
2734
2735	enum class AtomicArgumentOrder { API, AST };
2736	ExprResult
2737	BuildAtomicExpr(SourceRange CallRange, SourceRange ExprRange,
2738	SourceLocation RParenLoc, MultiExprArg Args,
2739	AtomicExpr::AtomicOp Op,
2740	AtomicArgumentOrder ArgOrder = AtomicArgumentOrder::API);
2741
2742	/// Check to see if a given expression could have '.c_str()' called on it.
2743	bool hasCStrMethod(const Expr *E);
2744
2745	/// Diagnose pointers that are always non-null.
2746	/// \param E the expression containing the pointer
2747	/// \param NullKind NPCK_NotNull if E is a cast to bool, otherwise, E is
2748	/// compared to a null pointer
2749	/// \param IsEqual True when the comparison is equal to a null pointer
2750	/// \param Range Extra SourceRange to highlight in the diagnostic
2751	void DiagnoseAlwaysNonNullPointer(Expr *E,
2752	Expr::NullPointerConstantKind NullType,
2753	bool IsEqual, SourceRange Range);
2754
2755	/// CheckParmsForFunctionDef - Check that the parameters of the given
2756	/// function are appropriate for the definition of a function. This
2757	/// takes care of any checks that cannot be performed on the
2758	/// declaration itself, e.g., that the types of each of the function
2759	/// parameters are complete.
2760	bool CheckParmsForFunctionDef(ArrayRef<ParmVarDecl *> Parameters,
2761	bool CheckParameterNames);
2762
2763	/// CheckCastAlign - Implements -Wcast-align, which warns when a
2764	/// pointer cast increases the alignment requirements.
2765	void CheckCastAlign(Expr *Op, QualType T, SourceRange TRange);
2766
2767	/// checkUnsafeAssigns - Check whether +1 expr is being assigned
2768	/// to weak/__unsafe_unretained type.
2769	bool checkUnsafeAssigns(SourceLocation Loc, QualType LHS, Expr *RHS);
2770
2771	/// checkUnsafeExprAssigns - Check whether +1 expr is being assigned
2772	/// to weak/__unsafe_unretained expression.
2773	void checkUnsafeExprAssigns(SourceLocation Loc, Expr LHS, Expr RHS);
2774
2775	/// Emit \p DiagID if statement located on \p StmtLoc has a suspicious null
2776	/// statement as a \p Body, and it is located on the same line.
2777	///
2778	/// This helps prevent bugs due to typos, such as:
2779	/// if (condition);
2780	/// do_stuff();
2781	void DiagnoseEmptyStmtBody(SourceLocation StmtLoc, const Stmt *Body,
2782	unsigned DiagID);
2783
2784	/// Warn if a for/while loop statement \p S, which is followed by
2785	/// \p PossibleBody, has a suspicious null statement as a body.
2786	void DiagnoseEmptyLoopBody(const Stmt S, const* Stmt *PossibleBody);
2787
2788	/// DiagnoseSelfMove - Emits a warning if a value is moved to itself.
2789	void DiagnoseSelfMove(const Expr LHSExpr, const* Expr *RHSExpr,
2790	SourceLocation OpLoc);
2791
2792	bool IsLayoutCompatible(QualType T1, QualType T2) const;
2793	bool IsPointerInterconvertibleBaseOf(const TypeSourceInfo *Base,
2794	const TypeSourceInfo *Derived);
2795
2796	/// CheckFunctionCall - Check a direct function call for various correctness
2797	/// and safety properties not strictly enforced by the C type system.
2798	bool CheckFunctionCall(FunctionDecl FDecl, CallExpr TheCall,
2799	const FunctionProtoType *Proto);
2800
2801	enum class EltwiseBuiltinArgTyRestriction {
2802	None,
2803	FloatTy,
2804	IntegerTy,
2805	SignedIntOrFloatTy,
2806	};
2807
2808	/// \param FPOnly restricts the arguments to floating-point types.
2809	std::optional<QualType>
2810	BuiltinVectorMath(CallExpr *TheCall,
2811	EltwiseBuiltinArgTyRestriction ArgTyRestr =
2812	EltwiseBuiltinArgTyRestriction::None);
2813	bool BuiltinVectorToScalarMath(CallExpr *TheCall);
2814
2815	void checkLifetimeCaptureBy(FunctionDecl FDecl, bool* IsMemberFunction,
2816	const Expr ThisArg, ArrayRef<const* Expr *> Args);
2817
2818	/// Handles the checks for format strings, non-POD arguments to vararg
2819	/// functions, NULL arguments passed to non-NULL parameters, diagnose_if
2820	/// attributes and AArch64 SME attributes.
2821	void checkCall(NamedDecl FDecl, const* FunctionProtoType *Proto,
2822	const Expr ThisArg, ArrayRef<const* Expr *> Args,
2823	bool IsMemberFunction, SourceLocation Loc, SourceRange Range,
2824	VariadicCallType CallType);
2825
2826	/// Verify that two format strings (as understood by attribute(format) and
2827	/// attribute(format_matches) are compatible. If they are incompatible,
2828	/// diagnostics are emitted with the assumption that \c
2829	/// AuthoritativeFormatString is correct and
2830	/// \c TestedFormatString is wrong. If \c FunctionCallArg is provided,
2831	/// diagnostics will point to it and a note will refer to \c
2832	/// TestedFormatString or \c AuthoritativeFormatString as appropriate.
2833	bool
2834	CheckFormatStringsCompatible(FormatStringType FST,
2835	const StringLiteral *AuthoritativeFormatString,
2836	const StringLiteral *TestedFormatString,
2837	const Expr FunctionCallArg = nullptr*);
2838
2839	/// Verify that one format string (as understood by attribute(format)) is
2840	/// self-consistent; for instance, that it doesn't have multiple positional
2841	/// arguments referring to the same argument in incompatible ways. Diagnose
2842	/// if it isn't.
2843	bool ValidateFormatString(FormatStringType FST, const StringLiteral *Str);
2844
2845	/// \brief Enforce the bounds of a TCB
2846	/// CheckTCBEnforcement - Enforces that every function in a named TCB only
2847	/// directly calls other functions in the same TCB as marked by the
2848	/// enforce_tcb and enforce_tcb_leaf attributes.
2849	void CheckTCBEnforcement(const SourceLocation CallExprLoc,
2850	const NamedDecl *Callee);
2851
2852	void CheckConstrainedAuto(const AutoType *AutoT, SourceLocation Loc);
2853
2854	/// BuiltinConstantArg - Handle a check if argument ArgNum of CallExpr
2855	/// TheCall is a constant expression.
2856	bool BuiltinConstantArg(CallExpr TheCall, unsigned* ArgNum,
2857	llvm::APSInt &Result);
2858
2859	/// BuiltinConstantArgRange - Handle a check if argument ArgNum of CallExpr
2860	/// TheCall is a constant expression in the range [Low, High].
2861	bool BuiltinConstantArgRange(CallExpr TheCall, unsigned* ArgNum, int Low,
2862	int High, bool RangeIsError = true);
2863
2864	/// BuiltinConstantArgMultiple - Handle a check if argument ArgNum of CallExpr
2865	/// TheCall is a constant expression is a multiple of Num..
2866	bool BuiltinConstantArgMultiple(CallExpr TheCall, unsigned* ArgNum,
2867	unsigned Multiple);
2868
2869	/// BuiltinConstantArgPower2 - Check if argument ArgNum of TheCall is a
2870	/// constant expression representing a power of 2.
2871	bool BuiltinConstantArgPower2(CallExpr TheCall, unsigned* ArgNum);
2872
2873	/// BuiltinConstantArgShiftedByte - Check if argument ArgNum of TheCall is
2874	/// a constant expression representing an arbitrary byte value shifted left by
2875	/// a multiple of 8 bits.
2876	bool BuiltinConstantArgShiftedByte(CallExpr TheCall, unsigned* ArgNum,
2877	unsigned ArgBits);
2878
2879	/// BuiltinConstantArgShiftedByteOr0xFF - Check if argument ArgNum of
2880	/// TheCall is a constant expression representing either a shifted byte value,
2881	/// or a value of the form 0x??FF (i.e. a member of the arithmetic progression
2882	/// 0x00FF, 0x01FF, ..., 0xFFFF). This strange range check is needed for some
2883	/// Arm MVE intrinsics.
2884	bool BuiltinConstantArgShiftedByteOrXXFF(CallExpr TheCall, unsigned* ArgNum,
2885	unsigned ArgBits);
2886
2887	/// Checks that a call expression's argument count is at least the desired
2888	/// number. This is useful when doing custom type-checking on a variadic
2889	/// function. Returns true on error.
2890	bool checkArgCountAtLeast(CallExpr Call, unsigned* MinArgCount);
2891
2892	/// Checks that a call expression's argument count is at most the desired
2893	/// number. This is useful when doing custom type-checking on a variadic
2894	/// function. Returns true on error.
2895	bool checkArgCountAtMost(CallExpr Call, unsigned* MaxArgCount);
2896
2897	/// Checks that a call expression's argument count is in the desired range.
2898	/// This is useful when doing custom type-checking on a variadic function.
2899	/// Returns true on error.
2900	bool checkArgCountRange(CallExpr Call, unsigned* MinArgCount,
2901	unsigned MaxArgCount);
2902
2903	/// Checks that a call expression's argument count is the desired number.
2904	/// This is useful when doing custom type-checking. Returns true on error.
2905	bool checkArgCount(CallExpr Call, unsigned* DesiredArgCount);
2906
2907	/// Returns true if the argument consists of one contiguous run of 1s with any
2908	/// number of 0s on either side. The 1s are allowed to wrap from LSB to MSB,
2909	/// so 0x000FFF0, 0x0000FFFF, 0xFF0000FF, 0x0 are all runs. 0x0F0F0000 is not,
2910	/// since all 1s are not contiguous.
2911	bool ValueIsRunOfOnes(CallExpr TheCall, unsigned* ArgNum);
2912
2913	void CheckImplicitConversion(Expr *E, QualType T, SourceLocation CC,
2914	bool ICContext = nullptr*,
2915	bool IsListInit = false);
2916
2917	/// Check for overflow behavior type related implicit conversion diagnostics.
2918	/// Returns true if OBT-related diagnostic was issued, false otherwise.
2919	bool CheckOverflowBehaviorTypeConversion(Expr *E, QualType T,
2920	SourceLocation CC);
2921
2922	bool
2923	BuiltinElementwiseTernaryMath(CallExpr *TheCall,
2924	EltwiseBuiltinArgTyRestriction ArgTyRestr =
2925	EltwiseBuiltinArgTyRestriction::FloatTy);
2926	bool PrepareBuiltinElementwiseMathOneArgCall(
2927	CallExpr *TheCall, EltwiseBuiltinArgTyRestriction ArgTyRestr =
2928	EltwiseBuiltinArgTyRestriction::None);
2929
2930	private:
2931	void CheckArrayAccess(const Expr BaseExpr, const* Expr *IndexExpr,
2932	const ArraySubscriptExpr ASE = nullptr*,
2933	bool AllowOnePastEnd = true, bool IndexNegated = false);
2934	void CheckArrayAccess(const Expr *E);
2935
2936	bool CheckPointerCall(NamedDecl NDecl, CallExpr TheCall,
2937	const FunctionProtoType *Proto);
2938
2939	/// Checks function calls when a FunctionDecl or a NamedDecl is not available,
2940	/// such as function pointers returned from functions.
2941	bool CheckOtherCall(CallExpr TheCall, const* FunctionProtoType *Proto);
2942
2943	/// CheckConstructorCall - Check a constructor call for correctness and safety
2944	/// properties not enforced by the C type system.
2945	void CheckConstructorCall(FunctionDecl *FDecl, QualType ThisType,
2946	ArrayRef<const Expr *> Args,
2947	const FunctionProtoType *Proto, SourceLocation Loc);
2948
2949	/// Warn if a pointer or reference argument passed to a function points to an
2950	/// object that is less aligned than the parameter. This can happen when
2951	/// creating a typedef with a lower alignment than the original type and then
2952	/// calling functions defined in terms of the original type.
2953	void CheckArgAlignment(SourceLocation Loc, NamedDecl *FDecl,
2954	StringRef ParamName, QualType ArgTy, QualType ParamTy);
2955
2956	ExprResult CheckOSLogFormatStringArg(Expr *Arg);
2957
2958	ExprResult CheckBuiltinFunctionCall(FunctionDecl FDecl, unsigned* BuiltinID,
2959	CallExpr *TheCall);
2960
2961	bool CheckTSBuiltinFunctionCall(const TargetInfo &TI, unsigned BuiltinID,
2962	CallExpr *TheCall);
2963
2964	void checkFortifiedBuiltinMemoryFunction(FunctionDecl FD, CallExpr TheCall);
2965
2966	/// Check the arguments to '__builtin_va_start', '__builtin_ms_va_start',
2967	/// or '__builtin_c23_va_start' for validity. Emit an error and return true
2968	/// on failure; return false on success.
2969	bool BuiltinVAStart(unsigned BuiltinID, CallExpr *TheCall);
2970	bool BuiltinVAStartARMMicrosoft(CallExpr *Call);
2971
2972	/// BuiltinUnorderedCompare - Handle functions like __builtin_isgreater and
2973	/// friends. This is declared to take (...), so we have to check everything.
2974	bool BuiltinUnorderedCompare(CallExpr TheCall, unsigned* BuiltinID);
2975
2976	/// BuiltinSemaBuiltinFPClassification - Handle functions like
2977	/// __builtin_isnan and friends. This is declared to take (...), so we have
2978	/// to check everything.
2979	bool BuiltinFPClassification(CallExpr TheCall, unsigned* NumArgs,
2980	unsigned BuiltinID);
2981
2982	/// Perform semantic analysis for a call to __builtin_complex.
2983	bool BuiltinComplex(CallExpr *TheCall);
2984	bool BuiltinOSLogFormat(CallExpr *TheCall);
2985
2986	/// BuiltinPrefetch - Handle __builtin_prefetch.
2987	/// This is declared to take (const void, ...) and can take two*
2988	/// optional constant int args.
2989	bool BuiltinPrefetch(CallExpr *TheCall);
2990
2991	/// Handle __builtin_alloca_with_align. This is declared
2992	/// as (size_t, size_t) where the second size_t must be a power of 2 greater
2993	/// than 8.
2994	bool BuiltinAllocaWithAlign(CallExpr *TheCall);
2995
2996	/// BuiltinArithmeticFence - Handle __arithmetic_fence.
2997	bool BuiltinArithmeticFence(CallExpr *TheCall);
2998
2999	/// BuiltinAssume - Handle __assume (MS Extension).
3000	/// __assume does not evaluate its arguments, and should warn if its argument
3001	/// has side effects.
3002	bool BuiltinAssume(CallExpr *TheCall);
3003
3004	/// Handle __builtin_assume_aligned. This is declared
3005	/// as (const void, size_t, ...) and can take one optional constant int arg.*
3006	bool BuiltinAssumeAligned(CallExpr *TheCall);
3007
3008	/// BuiltinLongjmp - Handle __builtin_longjmp(void env[5], int val).*
3009	/// This checks that the target supports __builtin_longjmp and
3010	/// that val is a constant 1.
3011	bool BuiltinLongjmp(CallExpr *TheCall);
3012
3013	/// BuiltinSetjmp - Handle __builtin_setjmp(void env[5]).*
3014	/// This checks that the target supports __builtin_setjmp.
3015	bool BuiltinSetjmp(CallExpr *TheCall);
3016
3017	/// We have a call to a function like __sync_fetch_and_add, which is an
3018	/// overloaded function based on the pointer type of its first argument.
3019	/// The main BuildCallExpr routines have already promoted the types of
3020	/// arguments because all of these calls are prototyped as void(...).
3021	///
3022	/// This function goes through and does final semantic checking for these
3023	/// builtins, as well as generating any warnings.
3024	ExprResult BuiltinAtomicOverloaded(ExprResult TheCallResult);
3025
3026	/// BuiltinNontemporalOverloaded - We have a call to
3027	/// __builtin_nontemporal_store or __builtin_nontemporal_load, which is an
3028	/// overloaded function based on the pointer type of its last argument.
3029	///
3030	/// This function goes through and does final semantic checking for these
3031	/// builtins.
3032	ExprResult BuiltinNontemporalOverloaded(ExprResult TheCallResult);
3033	ExprResult AtomicOpsOverloaded(ExprResult TheCallResult,
3034	AtomicExpr::AtomicOp Op);
3035
3036	/// \param FPOnly restricts the arguments to floating-point types.
3037	bool BuiltinElementwiseMath(CallExpr *TheCall,
3038	EltwiseBuiltinArgTyRestriction ArgTyRestr =
3039	EltwiseBuiltinArgTyRestriction::None);
3040	bool PrepareBuiltinReduceMathOneArgCall(CallExpr *TheCall);
3041
3042	bool BuiltinNonDeterministicValue(CallExpr *TheCall);
3043
3044	bool CheckInvalidBuiltinCountedByRef(const Expr *E,
3045	BuiltinCountedByRefKind K);
3046	bool BuiltinCountedByRef(CallExpr *TheCall);
3047
3048	// Matrix builtin handling.
3049	ExprResult BuiltinMatrixTranspose(CallExpr *TheCall, ExprResult CallResult);
3050	ExprResult BuiltinMatrixColumnMajorLoad(CallExpr *TheCall,
3051	ExprResult CallResult);
3052	ExprResult BuiltinMatrixColumnMajorStore(CallExpr *TheCall,
3053	ExprResult CallResult);
3054
3055	/// CheckFormatArguments - Check calls to printf and scanf (and similar
3056	/// functions) for correct use of format strings.
3057	/// Returns true if a format string has been fully checked.
3058	bool CheckFormatArguments(const FormatAttr *Format,
3059	ArrayRef<const Expr > Args, bool* IsCXXMember,
3060	VariadicCallType CallType, SourceLocation Loc,
3061	SourceRange Range,
3062	llvm::SmallBitVector &CheckedVarArgs);
3063	bool CheckFormatString(const FormatMatchesAttr *Format,
3064	ArrayRef<const Expr > Args, bool* IsCXXMember,
3065	VariadicCallType CallType, SourceLocation Loc,
3066	SourceRange Range,
3067	llvm::SmallBitVector &CheckedVarArgs);
3068	bool CheckFormatArguments(ArrayRef<const Expr *> Args,
3069	FormatArgumentPassingKind FAPK,
3070	StringLiteral *ReferenceFormatString,
3071	unsigned format_idx, unsigned firstDataArg,
3072	FormatStringType Type, VariadicCallType CallType,
3073	SourceLocation Loc, SourceRange range,
3074	llvm::SmallBitVector &CheckedVarArgs);
3075
3076	void CheckInfNaNFunction(const CallExpr Call, const* FunctionDecl *FDecl);
3077
3078	/// Warn when using the wrong abs() function.
3079	void CheckAbsoluteValueFunction(const CallExpr *Call,
3080	const FunctionDecl *FDecl);
3081
3082	void CheckMaxUnsignedZero(const CallExpr Call, const* FunctionDecl *FDecl);
3083
3084	/// Check for dangerous or invalid arguments to memset().
3085	///
3086	/// This issues warnings on known problematic, dangerous or unspecified
3087	/// arguments to the standard 'memset', 'memcpy', 'memmove', and 'memcmp'
3088	/// function calls.
3089	///
3090	/// \param Call The call expression to diagnose.
3091	void CheckMemaccessArguments(const CallExpr Call, unsigned* BId,
3092	IdentifierInfo *FnName);
3093
3094	bool CheckSizeofMemaccessArgument(const Expr SizeOfArg, const* Expr *Dest,
3095	IdentifierInfo *FnName);
3096	// Warn if the user has made the 'size' argument to strlcpy or strlcat
3097	// be the size of the source, instead of the destination.
3098	void CheckStrlcpycatArguments(const CallExpr Call, IdentifierInfo FnName);
3099
3100	// Warn on anti-patterns as the 'size' argument to strncat.
3101	// The correct size argument should look like following:
3102	// strncat(dst, src, sizeof(dst) - strlen(dest) - 1);
3103	void CheckStrncatArguments(const CallExpr *Call,
3104	const IdentifierInfo *FnName);
3105
3106	/// Alerts the user that they are attempting to free a non-malloc'd object.
3107	void CheckFreeArguments(const CallExpr *E);
3108
3109	void CheckReturnValExpr(Expr *RetValExp, QualType lhsType,
3110	SourceLocation ReturnLoc, bool isObjCMethod = false,
3111	const AttrVec Attrs = nullptr*,
3112	const FunctionDecl FD = nullptr*);
3113
3114	/// Diagnoses "dangerous" implicit conversions within the given
3115	/// expression (which is a full expression). Implements -Wconversion
3116	/// and -Wsign-compare.
3117	///
3118	/// \param CC the "context" location of the implicit conversion, i.e.
3119	/// the most location of the syntactic entity requiring the implicit
3120	/// conversion
3121	void CheckImplicitConversions(Expr *E, SourceLocation CC = SourceLocation ());
3122
3123	/// CheckBoolLikeConversion - Check conversion of given expression to boolean.
3124	/// Input argument E is a logical expression.
3125	void CheckBoolLikeConversion(Expr *E, SourceLocation CC);
3126
3127	/// Diagnose when expression is an integer constant expression and its
3128	/// evaluation results in integer overflow
3129	void CheckForIntOverflow(const Expr *E);
3130	void CheckUnsequencedOperations(const Expr *E);
3131
3132	/// Perform semantic checks on a completed expression. This will either
3133	/// be a full-expression or a default argument expression.
3134	void CheckCompletedExpr(Expr *E, SourceLocation CheckLoc = SourceLocation (),
3135	bool IsConstexpr = false);
3136
3137	void CheckBitFieldInitialization(SourceLocation InitLoc, FieldDecl *Field,
3138	Expr *Init);
3139
3140	/// A map from magic value to type information.
3141	std::unique_ptr<llvm::DenseMap<TypeTagMagicValue, TypeTagData>>
3142	TypeTagForDatatypeMagicValues;
3143
3144	/// Peform checks on a call of a function with argument_with_type_tag
3145	/// or pointer_with_type_tag attributes.
3146	void CheckArgumentWithTypeTag(const ArgumentWithTypeTagAttr *Attr,
3147	const ArrayRef<const Expr *> ExprArgs,
3148	SourceLocation CallSiteLoc);
3149
3150	/// Check if we are taking the address of a packed field
3151	/// as this may be a problem if the pointer value is dereferenced.
3152	void CheckAddressOfPackedMember(Expr *rhs);
3153
3154	/// Helper class that collects misaligned member designations and
3155	/// their location info for delayed diagnostics.
3156	struct MisalignedMember {
3157	Expr *E;
3158	RecordDecl *RD;
3159	ValueDecl *MD;
3160	CharUnits Alignment;
3161
3162	MisalignedMember() : E(), RD(), MD() {}
3163	MisalignedMember(Expr E, RecordDecl RD, ValueDecl *MD,
3164	CharUnits Alignment)
3165	: E(E), RD(RD), MD(MD), Alignment (Alignment) {}
3166	explicit MisalignedMember(Expr *E)
3167	: MisalignedMember (E, nullptr, nullptr, CharUnits ()) {}
3168
3169	bool operator==(const MisalignedMember &m) { return this->E == m.E; }
3170	};
3171
3172	/// Adds an expression to the set of gathered misaligned members.
3173	void AddPotentialMisalignedMembers(Expr E, RecordDecl RD, ValueDecl *MD,
3174	CharUnits Alignment);
3175	///@}
3176
3177	//
3178	//
3179	// -------------------------------------------------------------------------
3180	//
3181	//
3182
3183	/// \name C++ Coroutines
3184	/// Implementations are in SemaCoroutine.cpp
3185	///@{
3186
3187	public:
3188	/// The C++ "std::coroutine_traits" template, which is defined in
3189	/// \<coroutine_traits>
3190	ClassTemplateDecl *StdCoroutineTraitsCache;
3191
3192	bool ActOnCoroutineBodyStart(Scope *S, SourceLocation KwLoc,
3193	StringRef Keyword);
3194	ExprResult ActOnCoawaitExpr(Scope S, SourceLocation KwLoc, Expr E);
3195	ExprResult ActOnCoyieldExpr(Scope S, SourceLocation KwLoc, Expr E);
3196	StmtResult ActOnCoreturnStmt(Scope S, SourceLocation KwLoc, Expr E);
3197
3198	ExprResult BuildOperatorCoawaitLookupExpr(Scope *S, SourceLocation Loc);
3199	ExprResult BuildOperatorCoawaitCall(SourceLocation Loc, Expr *E,
3200	UnresolvedLookupExpr *Lookup);
3201	ExprResult BuildResolvedCoawaitExpr(SourceLocation KwLoc, Expr *Operand,
3202	Expr Awaiter, bool* IsImplicit = false);
3203	ExprResult BuildUnresolvedCoawaitExpr(SourceLocation KwLoc, Expr *Operand,
3204	UnresolvedLookupExpr *Lookup);
3205	ExprResult BuildCoyieldExpr(SourceLocation KwLoc, Expr *E);
3206	StmtResult BuildCoreturnStmt(SourceLocation KwLoc, Expr *E,
3207	bool IsImplicit = false);
3208	StmtResult BuildCoroutineBodyStmt(CoroutineBodyStmt::CtorArgs);
3209	bool buildCoroutineParameterMoves(SourceLocation Loc);
3210	VarDecl *buildCoroutinePromise(SourceLocation Loc);
3211	void CheckCompletedCoroutineBody(FunctionDecl FD, Stmt &Body);
3212
3213	// As a clang extension, enforces that a non-coroutine function must be marked
3214	// with [[clang::coro_wrapper]] if it returns a type marked with
3215	// [[clang::coro_return_type]].
3216	// Expects that FD is not a coroutine.
3217	void CheckCoroutineWrapper(FunctionDecl *FD);
3218	/// Lookup 'coroutine_traits' in std namespace and std::experimental
3219	/// namespace. The namespace found is recorded in Namespace.
3220	ClassTemplateDecl *lookupCoroutineTraits(SourceLocation KwLoc,
3221	SourceLocation FuncLoc);
3222	/// Check that the expression co_await promise.final_suspend() shall not be
3223	/// potentially-throwing.
3224	bool checkFinalSuspendNoThrow(const Stmt *FinalSuspend);
3225
3226	///@}
3227
3228	//
3229	//
3230	// -------------------------------------------------------------------------
3231	//
3232	//
3233
3234	/// \name C++ Scope Specifiers
3235	/// Implementations are in SemaCXXScopeSpec.cpp
3236	///@{
3237
3238	public:
3239	// Marks SS invalid if it represents an incomplete type.
3240	bool RequireCompleteDeclContext(CXXScopeSpec &SS, DeclContext *DC);
3241	// Complete an enum decl, maybe without a scope spec.
3242	bool RequireCompleteEnumDecl(EnumDecl *D, SourceLocation L,
3243	CXXScopeSpec SS = nullptr*);
3244
3245	/// Compute the DeclContext that is associated with the given type.
3246	///
3247	/// \param T the type for which we are attempting to find a DeclContext.
3248	///
3249	/// \returns the declaration context represented by the type T,
3250	/// or NULL if the declaration context cannot be computed (e.g., because it is
3251	/// dependent and not the current instantiation).
3252	DeclContext *computeDeclContext(QualType T);
3253
3254	/// Compute the DeclContext that is associated with the given
3255	/// scope specifier.
3256	///
3257	/// \param SS the C++ scope specifier as it appears in the source
3258	///
3259	/// \param EnteringContext when true, we will be entering the context of
3260	/// this scope specifier, so we can retrieve the declaration context of a
3261	/// class template or class template partial specialization even if it is
3262	/// not the current instantiation.
3263	///
3264	/// \returns the declaration context represented by the scope specifier @p SS,
3265	/// or NULL if the declaration context cannot be computed (e.g., because it is
3266	/// dependent and not the current instantiation).
3267	DeclContext computeDeclContext(const* CXXScopeSpec &SS,
3268	bool EnteringContext = false);
3269	bool isDependentScopeSpecifier(const CXXScopeSpec &SS);
3270
3271	/// If the given nested name specifier refers to the current
3272	/// instantiation, return the declaration that corresponds to that
3273	/// current instantiation (C++0x [temp.dep.type]p1).
3274	///
3275	/// \param NNS a dependent nested name specifier.
3276	CXXRecordDecl *getCurrentInstantiationOf(NestedNameSpecifier NNS);
3277
3278	/// The parser has parsed a global nested-name-specifier '::'.
3279	///
3280	/// \param CCLoc The location of the '::'.
3281	///
3282	/// \param SS The nested-name-specifier, which will be updated in-place
3283	/// to reflect the parsed nested-name-specifier.
3284	///
3285	/// \returns true if an error occurred, false otherwise.
3286	bool ActOnCXXGlobalScopeSpecifier(SourceLocation CCLoc, CXXScopeSpec &SS);
3287
3288	/// The parser has parsed a '__super' nested-name-specifier.
3289	///
3290	/// \param SuperLoc The location of the '__super' keyword.
3291	///
3292	/// \param ColonColonLoc The location of the '::'.
3293	///
3294	/// \param SS The nested-name-specifier, which will be updated in-place
3295	/// to reflect the parsed nested-name-specifier.
3296	///
3297	/// \returns true if an error occurred, false otherwise.
3298	bool ActOnSuperScopeSpecifier(SourceLocation SuperLoc,
3299	SourceLocation ColonColonLoc, CXXScopeSpec &SS);
3300
3301	/// Determines whether the given declaration is an valid acceptable
3302	/// result for name lookup of a nested-name-specifier.
3303	/// \param SD Declaration checked for nested-name-specifier.
3304	/// \param IsExtension If not null and the declaration is accepted as an
3305	/// extension, the pointed variable is assigned true.
3306	bool isAcceptableNestedNameSpecifier(const NamedDecl *SD,
3307	bool CanCorrect = nullptr*);
3308
3309	/// If the given nested-name-specifier begins with a bare identifier
3310	/// (e.g., Base::), perform name lookup for that identifier as a
3311	/// nested-name-specifier within the given scope, and return the result of
3312	/// that name lookup.
3313	NamedDecl FindFirstQualifierInScope(Scope S, NestedNameSpecifier NNS);
3314
3315	/// Keeps information about an identifier in a nested-name-spec.
3316	///
3317	struct NestedNameSpecInfo {
3318	/// The type of the object, if we're parsing nested-name-specifier in
3319	/// a member access expression.
3320	ParsedType ObjectType;
3321
3322	/// The identifier preceding the '::'.
3323	IdentifierInfo *Identifier;
3324
3325	/// The location of the identifier.
3326	SourceLocation IdentifierLoc;
3327
3328	/// The location of the '::'.
3329	SourceLocation CCLoc;
3330
3331	/// Creates info object for the most typical case.
3332	NestedNameSpecInfo(IdentifierInfo *II, SourceLocation IdLoc,
3333	SourceLocation ColonColonLoc,
3334	ParsedType ObjectType = ParsedType ())
3335	: ObjectType (ObjectType), Identifier(II), IdentifierLoc (IdLoc),
3336	CCLoc (ColonColonLoc) {}
3337
3338	NestedNameSpecInfo(IdentifierInfo *II, SourceLocation IdLoc,
3339	SourceLocation ColonColonLoc, QualType ObjectType)
3340	: ObjectType(ParsedType::make(P: ObjectType)), Identifier(II),
3341	IdentifierLoc (IdLoc), CCLoc (ColonColonLoc) {}
3342	};
3343
3344	/// Build a new nested-name-specifier for "identifier::", as described
3345	/// by ActOnCXXNestedNameSpecifier.
3346	///
3347	/// \param S Scope in which the nested-name-specifier occurs.
3348	/// \param IdInfo Parser information about an identifier in the
3349	/// nested-name-spec.
3350	/// \param EnteringContext If true, enter the context specified by the
3351	/// nested-name-specifier.
3352	/// \param SS Optional nested name specifier preceding the identifier.
3353	/// \param ScopeLookupResult Provides the result of name lookup within the
3354	/// scope of the nested-name-specifier that was computed at template
3355	/// definition time.
3356	/// \param ErrorRecoveryLookup Specifies if the method is called to improve
3357	/// error recovery and what kind of recovery is performed.
3358	/// \param IsCorrectedToColon If not null, suggestion of replace '::' -> ':'
3359	/// are allowed. The bool value pointed by this parameter is set to
3360	/// 'true' if the identifier is treated as if it was followed by ':',
3361	/// not '::'.
3362	/// \param OnlyNamespace If true, only considers namespaces in lookup.
3363	///
3364	/// This routine differs only slightly from ActOnCXXNestedNameSpecifier, in
3365	/// that it contains an extra parameter \p ScopeLookupResult, which provides
3366	/// the result of name lookup within the scope of the nested-name-specifier
3367	/// that was computed at template definition time.
3368	///
3369	/// If ErrorRecoveryLookup is true, then this call is used to improve error
3370	/// recovery. This means that it should not emit diagnostics, it should
3371	/// just return true on failure. It also means it should only return a valid
3372	/// scope if it knows* that the result is correct. It should not return in a*
3373	/// dependent context, for example. Nor will it extend \p SS with the scope
3374	/// specifier.
3375	bool BuildCXXNestedNameSpecifier(Scope *S, NestedNameSpecInfo &IdInfo,
3376	bool EnteringContext, CXXScopeSpec &SS,
3377	NamedDecl *ScopeLookupResult,
3378	bool ErrorRecoveryLookup,
3379	bool IsCorrectedToColon = nullptr*,
3380	bool OnlyNamespace = false);
3381
3382	/// The parser has parsed a nested-name-specifier 'identifier::'.
3383	///
3384	/// \param S The scope in which this nested-name-specifier occurs.
3385	///
3386	/// \param IdInfo Parser information about an identifier in the
3387	/// nested-name-spec.
3388	///
3389	/// \param EnteringContext Whether we're entering the context nominated by
3390	/// this nested-name-specifier.
3391	///
3392	/// \param SS The nested-name-specifier, which is both an input
3393	/// parameter (the nested-name-specifier before this type) and an
3394	/// output parameter (containing the full nested-name-specifier,
3395	/// including this new type).
3396	///
3397	/// \param IsCorrectedToColon If not null, suggestions to replace '::' -> ':'
3398	/// are allowed. The bool value pointed by this parameter is set to 'true'
3399	/// if the identifier is treated as if it was followed by ':', not '::'.
3400	///
3401	/// \param OnlyNamespace If true, only considers namespaces in lookup.
3402	///
3403	/// \returns true if an error occurred, false otherwise.
3404	bool ActOnCXXNestedNameSpecifier(Scope *S, NestedNameSpecInfo &IdInfo,
3405	bool EnteringContext, CXXScopeSpec &SS,
3406	bool IsCorrectedToColon = nullptr*,
3407	bool OnlyNamespace = false);
3408
3409	/// The parser has parsed a nested-name-specifier
3410	/// 'template[opt] template-name < template-args >::'.
3411	///
3412	/// \param S The scope in which this nested-name-specifier occurs.
3413	///
3414	/// \param SS The nested-name-specifier, which is both an input
3415	/// parameter (the nested-name-specifier before this type) and an
3416	/// output parameter (containing the full nested-name-specifier,
3417	/// including this new type).
3418	///
3419	/// \param TemplateKWLoc the location of the 'template' keyword, if any.
3420	/// \param TemplateName the template name.
3421	/// \param TemplateNameLoc The location of the template name.
3422	/// \param LAngleLoc The location of the opening angle bracket ('<').
3423	/// \param TemplateArgs The template arguments.
3424	/// \param RAngleLoc The location of the closing angle bracket ('>').
3425	/// \param CCLoc The location of the '::'.
3426	///
3427	/// \param EnteringContext Whether we're entering the context of the
3428	/// nested-name-specifier.
3429	///
3430	///
3431	/// \returns true if an error occurred, false otherwise.
3432	bool ActOnCXXNestedNameSpecifier(
3433	Scope *S, CXXScopeSpec &SS, SourceLocation TemplateKWLoc,
3434	TemplateTy TemplateName, SourceLocation TemplateNameLoc,
3435	SourceLocation LAngleLoc, ASTTemplateArgsPtr TemplateArgs,
3436	SourceLocation RAngleLoc, SourceLocation CCLoc, bool EnteringContext);
3437
3438	bool ActOnCXXNestedNameSpecifierDecltype(CXXScopeSpec &SS, const DeclSpec &DS,
3439	SourceLocation ColonColonLoc);
3440
3441	bool ActOnCXXNestedNameSpecifierIndexedPack(CXXScopeSpec &SS,
3442	const DeclSpec &DS,
3443	SourceLocation ColonColonLoc,
3444	QualType Type);
3445
3446	/// IsInvalidUnlessNestedName - This method is used for error recovery
3447	/// purposes to determine whether the specified identifier is only valid as
3448	/// a nested name specifier, for example a namespace name. It is
3449	/// conservatively correct to always return false from this method.
3450	///
3451	/// The arguments are the same as those passed to ActOnCXXNestedNameSpecifier.
3452	bool IsInvalidUnlessNestedName(Scope *S, CXXScopeSpec &SS,
3453	NestedNameSpecInfo &IdInfo,
3454	bool EnteringContext);
3455
3456	/// Given a C++ nested-name-specifier, produce an annotation value
3457	/// that the parser can use later to reconstruct the given
3458	/// nested-name-specifier.
3459	///
3460	/// \param SS A nested-name-specifier.
3461	///
3462	/// \returns A pointer containing all of the information in the
3463	/// nested-name-specifier \p SS.
3464	void *SaveNestedNameSpecifierAnnotation(CXXScopeSpec &SS);
3465
3466	/// Given an annotation pointer for a nested-name-specifier, restore
3467	/// the nested-name-specifier structure.
3468	///
3469	/// \param Annotation The annotation pointer, produced by
3470	/// \c SaveNestedNameSpecifierAnnotation().
3471	///
3472	/// \param AnnotationRange The source range corresponding to the annotation.
3473	///
3474	/// \param SS The nested-name-specifier that will be updated with the contents
3475	/// of the annotation pointer.
3476	void RestoreNestedNameSpecifierAnnotation(void *Annotation,
3477	SourceRange AnnotationRange,
3478	CXXScopeSpec &SS);
3479
3480	bool ShouldEnterDeclaratorScope(Scope S, const* CXXScopeSpec &SS);
3481
3482	/// ActOnCXXEnterDeclaratorScope - Called when a C++ scope specifier (global
3483	/// scope or nested-name-specifier) is parsed, part of a declarator-id.
3484	/// After this method is called, according to [C++ 3.4.3p3], names should be
3485	/// looked up in the declarator-id's scope, until the declarator is parsed and
3486	/// ActOnCXXExitDeclaratorScope is called.
3487	/// The 'SS' should be a non-empty valid CXXScopeSpec.
3488	bool ActOnCXXEnterDeclaratorScope(Scope *S, CXXScopeSpec &SS);
3489
3490	/// ActOnCXXExitDeclaratorScope - Called when a declarator that previously
3491	/// invoked ActOnCXXEnterDeclaratorScope(), is finished. 'SS' is the same
3492	/// CXXScopeSpec that was passed to ActOnCXXEnterDeclaratorScope as well.
3493	/// Used to indicate that names should revert to being looked up in the
3494	/// defining scope.
3495	void ActOnCXXExitDeclaratorScope(Scope S, const* CXXScopeSpec &SS);
3496
3497	///@}
3498
3499	//
3500	//
3501	// -------------------------------------------------------------------------
3502	//
3503	//
3504
3505	/// \name Declarations
3506	/// Implementations are in SemaDecl.cpp
3507	///@{
3508
3509	public:
3510	IdentifierResolver IdResolver;
3511
3512	/// The index of the first InventedParameterInfo that refers to the current
3513	/// context.
3514	unsigned InventedParameterInfosStart = `0`;
3515
3516	/// A RAII object to temporarily push a declaration context.
3517	class ContextRAII {
3518	private:
3519	Sema &S;
3520	DeclContext *SavedContext;
3521	ProcessingContextState SavedContextState;
3522	QualType SavedCXXThisTypeOverride;
3523	unsigned SavedFunctionScopesStart;
3524	unsigned SavedInventedParameterInfosStart;
3525
3526	public:
3527	ContextRAII(Sema &S, DeclContext ContextToPush, bool* NewThisContext = true)
3528	: S(S), SavedContext(S.CurContext),
3529	SavedContextState(S.DelayedDiagnostics.pushUndelayed()),
3530	SavedCXXThisTypeOverride (S.CXXThisTypeOverride),
3531	SavedFunctionScopesStart(S.FunctionScopesStart),
3532	SavedInventedParameterInfosStart(S.InventedParameterInfosStart) {
3533	assert(ContextToPush && "pushing null context");
3534	S.CurContext = ContextToPush;
3535	if (NewThisContext)
3536	S.CXXThisTypeOverride = QualType ();
3537	// Any saved FunctionScopes do not refer to this context.
3538	S.FunctionScopesStart = S.FunctionScopes.size();
3539	S.InventedParameterInfosStart = S.InventedParameterInfos.size();
3540	}
3541
3542	void pop() {
3543	if (!SavedContext)
3544	return;
3545	S.CurContext = SavedContext;
3546	S.DelayedDiagnostics.popUndelayed(state: SavedContextState);
3547	S.CXXThisTypeOverride = SavedCXXThisTypeOverride;
3548	S.FunctionScopesStart = SavedFunctionScopesStart;
3549	S.InventedParameterInfosStart = SavedInventedParameterInfosStart;
3550	SavedContext = nullptr;
3551	}
3552
3553	~ContextRAII() { pop(); }
3554	ContextRAII(const ContextRAII &) = delete;
3555	ContextRAII &operator=(const ContextRAII &) = delete;
3556	};
3557
3558	void DiagnoseInvalidJumps(Stmt *Body);
3559
3560	/// The function definitions which were renamed as part of typo-correction
3561	/// to match their respective declarations. We want to keep track of them
3562	/// to ensure that we don't emit a "redefinition" error if we encounter a
3563	/// correctly named definition after the renamed definition.
3564	llvm::SmallPtrSet<const NamedDecl *, `4`> TypoCorrectedFunctionDefinitions;
3565
3566	/// A cache of the flags available in enumerations with the flag_bits
3567	/// attribute.
3568	mutable llvm::DenseMap<const EnumDecl *, llvm::APInt> FlagBitsCache;
3569
3570	/// A cache of enumerator values for enums checked by -Wassign-enum.
3571	llvm::DenseMap<const EnumDecl *, llvm::SmallVector<llvm::APSInt>>
3572	AssignEnumCache;
3573
3574	/// WeakUndeclaredIdentifiers - Identifiers contained in \#pragma weak before
3575	/// declared. Rare. May alias another identifier, declared or undeclared.
3576	///
3577	/// For aliases, the target identifier is used as a key for eventual
3578	/// processing when the target is declared. For the single-identifier form,
3579	/// the sole identifier is used as the key. Each entry is a `SetVector`
3580	/// (ordered by parse order) of aliases (identified by the alias name) in case
3581	/// of multiple aliases to the same undeclared identifier.
3582	llvm::MapVector<
3583	IdentifierInfo *,
3584	llvm::SetVector<
3585	WeakInfo, llvm::SmallVector<WeakInfo, `1u`>,
3586	llvm::SmallDenseSet<WeakInfo, `2u`, WeakInfo::DenseMapInfoByAliasOnly>>>
3587	WeakUndeclaredIdentifiers;
3588
3589	/// ExtnameUndeclaredIdentifiers - Identifiers contained in
3590	/// \#pragma redefine_extname before declared. Used in Solaris system headers
3591	/// to define functions that occur in multiple standards to call the version
3592	/// in the currently selected standard.
3593	llvm::DenseMap<IdentifierInfo , AsmLabelAttr > ExtnameUndeclaredIdentifiers;
3594
3595	/// Set containing all typedefs that are likely unused.
3596	llvm::SmallSetVector<const TypedefNameDecl *, `4`>
3597	UnusedLocalTypedefNameCandidates;
3598
3599	typedef LazyVector<const DeclaratorDecl *, ExternalSemaSource,
3600	&ExternalSemaSource::ReadUnusedFileScopedDecls, `2`, `2`>
3601	UnusedFileScopedDeclsType;
3602
3603	/// The set of file scoped decls seen so far that have not been used
3604	/// and must warn if not used. Only contains the first declaration.
3605	UnusedFileScopedDeclsType UnusedFileScopedDecls;
3606
3607	typedef LazyVector<VarDecl *, ExternalSemaSource,
3608	&ExternalSemaSource::ReadTentativeDefinitions, `2`, `2`>
3609	TentativeDefinitionsType;
3610
3611	/// All the tentative definitions encountered in the TU.
3612	TentativeDefinitionsType TentativeDefinitions;
3613
3614	/// All the external declarations encoutered and used in the TU.
3615	SmallVector<DeclaratorDecl *, `4`> ExternalDeclarations;
3616
3617	/// Generally null except when we temporarily switch decl contexts,
3618	/// like in \see SemaObjC::ActOnObjCTemporaryExitContainerContext.
3619	DeclContext *OriginalLexicalContext;
3620
3621	/// Is the module scope we are in a C++ Header Unit?
3622	bool currentModuleIsHeaderUnit() const {
3623	return ModuleScopes.empty() ? false
3624	: ModuleScopes.back().Module->isHeaderUnit();
3625	}
3626
3627	/// Get the module owning an entity.
3628	Module getOwningModule(const* Decl *Entity) {
3629	return Entity->getOwningModule();
3630	}
3631
3632	DeclGroupPtrTy ConvertDeclToDeclGroup(Decl Ptr, Decl OwnedType = nullptr);
3633
3634	enum class DiagCtorKind { None, Implicit, Typename };
3635	/// Returns the TypeDeclType for the given type declaration,
3636	/// as ASTContext::getTypeDeclType would, but
3637	/// performs the required semantic checks for name lookup of said entity.
3638	void checkTypeDeclType(DeclContext LookupCtx, DiagCtorKind DCK, TypeDecl TD,
3639	SourceLocation NameLoc);
3640
3641	/// If the identifier refers to a type name within this scope,
3642	/// return the declaration of that type.
3643	///
3644	/// This routine performs ordinary name lookup of the identifier II
3645	/// within the given scope, with optional C++ scope specifier SS, to
3646	/// determine whether the name refers to a type. If so, returns an
3647	/// opaque pointer (actually a QualType) corresponding to that
3648	/// type. Otherwise, returns NULL.
3649	ParsedType getTypeName(const IdentifierInfo &II, SourceLocation NameLoc,
3650	Scope S, CXXScopeSpec SS = nullptr,
3651	bool isClassName = false, bool HasTrailingDot = false,
3652	ParsedType ObjectType = nullptr,
3653	bool IsCtorOrDtorName = false,
3654	bool WantNontrivialTypeSourceInfo = false,
3655	bool IsClassTemplateDeductionContext = true,
3656	ImplicitTypenameContext AllowImplicitTypename =
3657	ImplicitTypenameContext::No,
3658	IdentifierInfo CorrectedII = nullptr**);
3659
3660	/// isTagName() - This method is called for error recovery purposes only
3661	/// to determine if the specified name is a valid tag name ("struct foo"). If
3662	/// so, this returns the TST for the tag corresponding to it (TST_enum,
3663	/// TST_union, TST_struct, TST_interface, TST_class). This is used to
3664	/// diagnose cases in C where the user forgot to specify the tag.
3665	TypeSpecifierType isTagName(IdentifierInfo &II, Scope *S);
3666
3667	/// isMicrosoftMissingTypename - In Microsoft mode, within class scope,
3668	/// if a CXXScopeSpec's type is equal to the type of one of the base classes
3669	/// then downgrade the missing typename error to a warning.
3670	/// This is needed for MSVC compatibility; Example:
3671	/// @code
3672	/// template<class T> class A {
3673	/// public:
3674	/// typedef int TYPE;
3675	/// };
3676	/// template<class T> class B : public A<T> {
3677	/// public:
3678	/// A<T>::TYPE a; // no typename required because A<T> is a base class.
3679	/// };
3680	/// @endcode
3681	bool isMicrosoftMissingTypename(const CXXScopeSpec SS, Scope S);
3682	void DiagnoseUnknownTypeName(IdentifierInfo *&II, SourceLocation IILoc,
3683	Scope S, CXXScopeSpec SS,
3684	ParsedType &SuggestedType,
3685	bool IsTemplateName = false);
3686
3687	/// Attempt to behave like MSVC in situations where lookup of an unqualified
3688	/// type name has failed in a dependent context. In these situations, we
3689	/// automatically form a DependentTypeName that will retry lookup in a related
3690	/// scope during instantiation.
3691	ParsedType ActOnMSVCUnknownTypeName(const IdentifierInfo &II,
3692	SourceLocation NameLoc,
3693	bool IsTemplateTypeArg);
3694
3695	class NameClassification {
3696	NameClassificationKind Kind;
3697	union {
3698	ExprResult Expr;
3699	NamedDecl *NonTypeDecl;
3700	TemplateName Template;
3701	ParsedType Type;
3702	};
3703
3704	explicit NameClassification(NameClassificationKind Kind) : Kind(Kind) {}
3705
3706	public:
3707	NameClassification(ParsedType Type)
3708	: Kind(NameClassificationKind::Type), Type (Type) {}
3709
3710	NameClassification(const IdentifierInfo *Keyword)
3711	: Kind(NameClassificationKind::Keyword) {}
3712
3713	static NameClassification Error() {
3714	return NameClassification (NameClassificationKind::Error);
3715	}
3716
3717	static NameClassification Unknown() {
3718	return NameClassification (NameClassificationKind::Unknown);
3719	}
3720
3721	static NameClassification OverloadSet(ExprResult E) {
3722	NameClassification Result(NameClassificationKind::OverloadSet);
3723	Result.Expr = E;
3724	return Result;
3725	}
3726
3727	static NameClassification NonType(NamedDecl *D) {
3728	NameClassification Result(NameClassificationKind::NonType);
3729	Result.NonTypeDecl = D;
3730	return Result;
3731	}
3732
3733	static NameClassification UndeclaredNonType() {
3734	return NameClassification (NameClassificationKind::UndeclaredNonType);
3735	}
3736
3737	static NameClassification DependentNonType() {
3738	return NameClassification (NameClassificationKind::DependentNonType);
3739	}
3740
3741	static NameClassification TypeTemplate(TemplateName Name) {
3742	NameClassification Result(NameClassificationKind::TypeTemplate);
3743	Result.Template = Name;
3744	return Result;
3745	}
3746
3747	static NameClassification VarTemplate(TemplateName Name) {
3748	NameClassification Result(NameClassificationKind::VarTemplate);
3749	Result.Template = Name;
3750	return Result;
3751	}
3752
3753	static NameClassification FunctionTemplate(TemplateName Name) {
3754	NameClassification Result(NameClassificationKind::FunctionTemplate);
3755	Result.Template = Name;
3756	return Result;
3757	}
3758
3759	static NameClassification Concept(TemplateName Name) {
3760	NameClassification Result(NameClassificationKind::Concept);
3761	Result.Template = Name;
3762	return Result;
3763	}
3764
3765	static NameClassification UndeclaredTemplate(TemplateName Name) {
3766	NameClassification Result(NameClassificationKind::UndeclaredTemplate);
3767	Result.Template = Name;
3768	return Result;
3769	}
3770
3771	NameClassificationKind getKind() const { return Kind; }
3772
3773	ExprResult getExpression() const {
3774	assert(Kind == NameClassificationKind::OverloadSet);
3775	return Expr;
3776	}
3777
3778	ParsedType getType() const {
3779	assert(Kind == NameClassificationKind::Type);
3780	return Type;
3781	}
3782
3783	NamedDecl getNonTypeDecl() const* {
3784	assert(Kind == NameClassificationKind::NonType);
3785	return NonTypeDecl;
3786	}
3787
3788	TemplateName getTemplateName() const {
3789	assert(Kind == NameClassificationKind::TypeTemplate \|\|
3790	Kind == NameClassificationKind::FunctionTemplate \|\|
3791	Kind == NameClassificationKind::VarTemplate \|\|
3792	Kind == NameClassificationKind::Concept \|\|
3793	Kind == NameClassificationKind::UndeclaredTemplate);
3794	return Template;
3795	}
3796
3797	TemplateNameKind getTemplateNameKind() const {
3798	switch (Kind) {
3799	case NameClassificationKind::TypeTemplate:
3800	return TNK_Type_template;
3801	case NameClassificationKind::FunctionTemplate:
3802	return TNK_Function_template;
3803	case NameClassificationKind::VarTemplate:
3804	return TNK_Var_template;
3805	case NameClassificationKind::Concept:
3806	return TNK_Concept_template;
3807	case NameClassificationKind::UndeclaredTemplate:
3808	return TNK_Undeclared_template;
3809	default:
3810	llvm_unreachable("unsupported name classification.");
3811	}
3812	}
3813	};
3814
3815	/// Perform name lookup on the given name, classifying it based on
3816	/// the results of name lookup and the following token.
3817	///
3818	/// This routine is used by the parser to resolve identifiers and help direct
3819	/// parsing. When the identifier cannot be found, this routine will attempt
3820	/// to correct the typo and classify based on the resulting name.
3821	///
3822	/// \param S The scope in which we're performing name lookup.
3823	///
3824	/// \param SS The nested-name-specifier that precedes the name.
3825	///
3826	/// \param Name The identifier. If typo correction finds an alternative name,
3827	/// this pointer parameter will be updated accordingly.
3828	///
3829	/// \param NameLoc The location of the identifier.
3830	///
3831	/// \param NextToken The token following the identifier. Used to help
3832	/// disambiguate the name.
3833	///
3834	/// \param CCC The correction callback, if typo correction is desired.
3835	NameClassification ClassifyName(Scope *S, CXXScopeSpec &SS,
3836	IdentifierInfo *&Name, SourceLocation NameLoc,
3837	const Token &NextToken,
3838	CorrectionCandidateCallback CCC = nullptr*);
3839
3840	/// Act on the result of classifying a name as an undeclared (ADL-only)
3841	/// non-type declaration.
3842	ExprResult ActOnNameClassifiedAsUndeclaredNonType(IdentifierInfo *Name,
3843	SourceLocation NameLoc);
3844	/// Act on the result of classifying a name as an undeclared member of a
3845	/// dependent base class.
3846	ExprResult ActOnNameClassifiedAsDependentNonType(const CXXScopeSpec &SS,
3847	IdentifierInfo *Name,
3848	SourceLocation NameLoc,
3849	bool IsAddressOfOperand);
3850	/// Act on the result of classifying a name as a specific non-type
3851	/// declaration.
3852	ExprResult ActOnNameClassifiedAsNonType(Scope S, const* CXXScopeSpec &SS,
3853	NamedDecl *Found,
3854	SourceLocation NameLoc,
3855	const Token &NextToken);
3856	/// Act on the result of classifying a name as an overload set.
3857	ExprResult ActOnNameClassifiedAsOverloadSet(Scope S, Expr OverloadSet);
3858
3859	/// Describes the detailed kind of a template name. Used in diagnostics.
3860	enum class TemplateNameKindForDiagnostics {
3861	ClassTemplate,
3862	FunctionTemplate,
3863	VarTemplate,
3864	AliasTemplate,
3865	TemplateTemplateParam,
3866	Concept,
3867	DependentTemplate
3868	};
3869	TemplateNameKindForDiagnostics
3870	getTemplateNameKindForDiagnostics(TemplateName Name);
3871
3872	/// Determine whether it's plausible that E was intended to be a
3873	/// template-name.
3874	bool mightBeIntendedToBeTemplateName(ExprResult E, bool &Dependent) {
3875	if (!getLangOpts().CPlusPlus \|\| E.isInvalid())
3876	return false;
3877	Dependent = false;
3878	if (auto *DRE = dyn_cast<DeclRefExpr>(Val: E.get()))
3879	return !DRE->hasExplicitTemplateArgs();
3880	if (auto *ME = dyn_cast<MemberExpr>(Val: E.get()))
3881	return !ME->hasExplicitTemplateArgs();
3882	Dependent = true;
3883	if (auto *DSDRE = dyn_cast<DependentScopeDeclRefExpr>(Val: E.get()))
3884	return !DSDRE->hasExplicitTemplateArgs();
3885	if (auto *DSME = dyn_cast<CXXDependentScopeMemberExpr>(Val: E.get()))
3886	return !DSME->hasExplicitTemplateArgs();
3887	// Any additional cases recognized here should also be handled by
3888	// diagnoseExprIntendedAsTemplateName.
3889	return false;
3890	}
3891
3892	void warnOnReservedIdentifier(const NamedDecl *D);
3893	void warnOnCTypeHiddenInCPlusPlus(const NamedDecl *D);
3894
3895	void ProcessPragmaExport(DeclaratorDecl *newDecl);
3896
3897	Decl ActOnDeclarator(Scope S, Declarator &D);
3898
3899	NamedDecl HandleDeclarator(Scope S, Declarator &D,
3900	MultiTemplateParamsArg TemplateParameterLists);
3901
3902	/// Attempt to fold a variable-sized type to a constant-sized type, returning
3903	/// true if we were successful.
3904	bool tryToFixVariablyModifiedVarType(TypeSourceInfo *&TInfo, QualType &T,
3905	SourceLocation Loc,
3906	unsigned FailedFoldDiagID);
3907
3908	/// Register the given locally-scoped extern "C" declaration so
3909	/// that it can be found later for redeclarations. We include any extern "C"
3910	/// declaration that is not visible in the translation unit here, not just
3911	/// function-scope declarations.
3912	void RegisterLocallyScopedExternCDecl(NamedDecl ND, Scope S);
3913
3914	/// DiagnoseClassNameShadow - Implement C++ [class.mem]p13:
3915	/// If T is the name of a class, then each of the following shall have a
3916	/// name different from T:
3917	/// - every static data member of class T;
3918	/// - every member function of class T
3919	/// - every member of class T that is itself a type;
3920	/// \returns true if the declaration name violates these rules.
3921	bool DiagnoseClassNameShadow(DeclContext *DC, DeclarationNameInfo Info);
3922
3923	/// Diagnose a declaration whose declarator-id has the given
3924	/// nested-name-specifier.
3925	///
3926	/// \param SS The nested-name-specifier of the declarator-id.
3927	///
3928	/// \param DC The declaration context to which the nested-name-specifier
3929	/// resolves.
3930	///
3931	/// \param Name The name of the entity being declared.
3932	///
3933	/// \param Loc The location of the name of the entity being declared.
3934	///
3935	/// \param IsMemberSpecialization Whether we are declaring a member
3936	/// specialization.
3937	///
3938	/// \param TemplateId The template-id, if any.
3939	///
3940	/// \returns true if we cannot safely recover from this error, false
3941	/// otherwise.
3942	bool diagnoseQualifiedDeclaration(CXXScopeSpec &SS, DeclContext *DC,
3943	DeclarationName Name, SourceLocation Loc,
3944	TemplateIdAnnotation *TemplateId,
3945	bool IsMemberSpecialization);
3946
3947	bool checkPointerAuthEnabled(SourceLocation Loc, SourceRange Range);
3948
3949	bool checkConstantPointerAuthKey(Expr keyExpr, unsigned* &key);
3950
3951	bool checkPointerAuthDiscriminatorArg(Expr *Arg, PointerAuthDiscArgKind Kind,
3952	unsigned &IntVal);
3953
3954	/// Diagnose function specifiers on a declaration of an identifier that
3955	/// does not identify a function.
3956	void DiagnoseFunctionSpecifiers(const DeclSpec &DS);
3957
3958	/// Return the declaration shadowed by the given typedef \p D, or null
3959	/// if it doesn't shadow any declaration or shadowing warnings are disabled.
3960	NamedDecl getShadowedDeclaration(const* TypedefNameDecl *D,
3961	const LookupResult &R);
3962
3963	/// Return the declaration shadowed by the given variable \p D, or null
3964	/// if it doesn't shadow any declaration or shadowing warnings are disabled.
3965	NamedDecl getShadowedDeclaration(const* VarDecl D, const* LookupResult &R);
3966
3967	/// Return the declaration shadowed by the given variable \p D, or null
3968	/// if it doesn't shadow any declaration or shadowing warnings are disabled.
3969	NamedDecl getShadowedDeclaration(const* BindingDecl *D,
3970	const LookupResult &R);
3971	/// Diagnose variable or built-in function shadowing. Implements
3972	/// -Wshadow.
3973	///
3974	/// This method is called whenever a VarDecl is added to a "useful"
3975	/// scope.
3976	///
3977	/// \param ShadowedDecl the declaration that is shadowed by the given variable
3978	/// \param R the lookup of the name
3979	void CheckShadow(NamedDecl D, NamedDecl ShadowedDecl,
3980	const LookupResult &R);
3981
3982	/// Check -Wshadow without the advantage of a previous lookup.
3983	void CheckShadow(Scope S, VarDecl D);
3984
3985	/// Warn if 'E', which is an expression that is about to be modified, refers
3986	/// to a shadowing declaration.
3987	void CheckShadowingDeclModification(Expr *E, SourceLocation Loc);
3988
3989	/// Diagnose shadowing for variables shadowed in the lambda record \p LambdaRD
3990	/// when these variables are captured by the lambda.
3991	void DiagnoseShadowingLambdaDecls(const sema::LambdaScopeInfo *LSI);
3992
3993	void handleTagNumbering(const TagDecl Tag, Scope TagScope);
3994	void setTagNameForLinkagePurposes(TagDecl *TagFromDeclSpec,
3995	TypedefNameDecl *NewTD);
3996	void CheckTypedefForVariablyModifiedType(Scope S, TypedefNameDecl D);
3997	NamedDecl ActOnTypedefDeclarator(Scope S, Declarator &D, DeclContext *DC,
3998	TypeSourceInfo *TInfo,
3999	LookupResult &Previous);
4000
4001	/// ActOnTypedefNameDecl - Perform semantic checking for a declaration which
4002	/// declares a typedef-name, either using the 'typedef' type specifier or via
4003	/// a C++0x [dcl.typedef]p2 alias-declaration: 'using T = A;'.
4004	NamedDecl ActOnTypedefNameDecl(Scope S, DeclContext DC, TypedefNameDecl D,
4005	LookupResult &Previous, bool &Redeclaration);
4006	NamedDecl ActOnVariableDeclarator(Scope S, Declarator &D, DeclContext *DC,
4007	TypeSourceInfo *TInfo,
4008	LookupResult &Previous,
4009	MultiTemplateParamsArg TemplateParamLists,
4010	bool &AddToScope,
4011	ArrayRef<BindingDecl *> Bindings = {});
4012
4013	private:
4014	// Perform a check on an AsmLabel to verify its consistency and emit
4015	// diagnostics in case of an error.
4016	void CheckAsmLabel(Scope S, Expr AsmLabelExpr, StorageClass SC,
4017	TypeSourceInfo TInfo, VarDecl );
4018
4019	public:
4020	/// Perform semantic checking on a newly-created variable
4021	/// declaration.
4022	///
4023	/// This routine performs all of the type-checking required for a
4024	/// variable declaration once it has been built. It is used both to
4025	/// check variables after they have been parsed and their declarators
4026	/// have been translated into a declaration, and to check variables
4027	/// that have been instantiated from a template.
4028	///
4029	/// Sets NewVD->isInvalidDecl() if an error was encountered.
4030	///
4031	/// Returns true if the variable declaration is a redeclaration.
4032	bool CheckVariableDeclaration(VarDecl *NewVD, LookupResult &Previous);
4033	void CheckVariableDeclarationType(VarDecl *NewVD);
4034	void CheckCompleteVariableDeclaration(VarDecl *VD);
4035
4036	NamedDecl ActOnFunctionDeclarator(Scope S, Declarator &D, DeclContext *DC,
4037	TypeSourceInfo *TInfo,
4038	LookupResult &Previous,
4039	MultiTemplateParamsArg TemplateParamLists,
4040	bool &AddToScope);
4041
4042	/// AddOverriddenMethods - See if a method overrides any in the base classes,
4043	/// and if so, check that it's a valid override and remember it.
4044	bool AddOverriddenMethods(CXXRecordDecl DC, CXXMethodDecl MD);
4045
4046	/// Perform semantic checking of a new function declaration.
4047	///
4048	/// Performs semantic analysis of the new function declaration
4049	/// NewFD. This routine performs all semantic checking that does not
4050	/// require the actual declarator involved in the declaration, and is
4051	/// used both for the declaration of functions as they are parsed
4052	/// (called via ActOnDeclarator) and for the declaration of functions
4053	/// that have been instantiated via C++ template instantiation (called
4054	/// via InstantiateDecl).
4055	///
4056	/// \param IsMemberSpecialization whether this new function declaration is
4057	/// a member specialization (that replaces any definition provided by the
4058	/// previous declaration).
4059	///
4060	/// This sets NewFD->isInvalidDecl() to true if there was an error.
4061	///
4062	/// \returns true if the function declaration is a redeclaration.
4063	bool CheckFunctionDeclaration(Scope S, FunctionDecl NewFD,
4064	LookupResult &Previous,
4065	bool IsMemberSpecialization, bool DeclIsDefn);
4066
4067	/// Checks if the new declaration declared in dependent context must be
4068	/// put in the same redeclaration chain as the specified declaration.
4069	///
4070	/// \param D Declaration that is checked.
4071	/// \param PrevDecl Previous declaration found with proper lookup method for
4072	/// the same declaration name.
4073	/// \returns True if D must be added to the redeclaration chain which PrevDecl
4074	/// belongs to.
4075	bool shouldLinkDependentDeclWithPrevious(Decl D, Decl OldDecl);
4076
4077	/// Determines if we can perform a correct type check for \p D as a
4078	/// redeclaration of \p PrevDecl. If not, we can generally still perform a
4079	/// best-effort check.
4080	///
4081	/// \param NewD The new declaration.
4082	/// \param OldD The old declaration.
4083	/// \param NewT The portion of the type of the new declaration to check.
4084	/// \param OldT The portion of the type of the old declaration to check.
4085	bool canFullyTypeCheckRedeclaration(ValueDecl NewD, ValueDecl OldD,
4086	QualType NewT, QualType OldT);
4087	void CheckMain(FunctionDecl FD, const* DeclSpec &D);
4088	void CheckMSVCRTEntryPoint(FunctionDecl *FD);
4089
4090	/// Returns an implicit CodeSegAttr if a __declspec(code_seg) is found on a
4091	/// containing class. Otherwise it will return implicit SectionAttr if the
4092	/// function is a definition and there is an active value on CodeSegStack
4093	/// (from the current #pragma code-seg value).
4094	///
4095	/// \param FD Function being declared.
4096	/// \param IsDefinition Whether it is a definition or just a declaration.
4097	/// \returns A CodeSegAttr or SectionAttr to apply to the function or
4098	/// nullptr if no attribute should be added.
4099	Attr getImplicitCodeSegOrSectionAttrForFunction(const* FunctionDecl *FD,
4100	bool IsDefinition);
4101
4102	/// Common checks for a parameter-declaration that should apply to both
4103	/// function parameters and non-type template parameters.
4104	void CheckFunctionOrTemplateParamDeclarator(Scope *S, Declarator &D);
4105
4106	/// ActOnParamDeclarator - Called from Parser::ParseFunctionDeclarator()
4107	/// to introduce parameters into function prototype scope.
4108	Decl ActOnParamDeclarator(Scope S, Declarator &D,
4109	SourceLocation ExplicitThisLoc = {});
4110
4111	/// Synthesizes a variable for a parameter arising from a
4112	/// typedef.
4113	ParmVarDecl BuildParmVarDeclForTypedef(DeclContext DC, SourceLocation Loc,
4114	QualType T);
4115	ParmVarDecl CheckParameter(DeclContext DC, SourceLocation StartLoc,
4116	SourceLocation NameLoc,
4117	const IdentifierInfo *Name, QualType T,
4118	TypeSourceInfo *TSInfo, StorageClass SC);
4119
4120	/// Emit diagnostics if the initializer or any of its explicit or
4121	/// implicitly-generated subexpressions require copying or
4122	/// default-initializing a type that is or contains a C union type that is
4123	/// non-trivial to copy or default-initialize.
4124	void checkNonTrivialCUnionInInitializer(const Expr *Init, SourceLocation Loc);
4125
4126	// These flags are passed to checkNonTrivialCUnion.
4127	enum NonTrivialCUnionKind {
4128	NTCUK_Init = `0x1`,
4129	NTCUK_Destruct = `0x2`,
4130	NTCUK_Copy = `0x4`,
4131	};
4132
4133	/// Emit diagnostics if a non-trivial C union type or a struct that contains
4134	/// a non-trivial C union is used in an invalid context.
4135	void checkNonTrivialCUnion(QualType QT, SourceLocation Loc,
4136	NonTrivialCUnionContext UseContext,
4137	unsigned NonTrivialKind);
4138
4139	/// Certain globally-unique variables might be accidentally duplicated if
4140	/// built into multiple shared libraries with hidden visibility. This can
4141	/// cause problems if the variable is mutable, its initialization is
4142	/// effectful, or its address is taken.
4143	bool GloballyUniqueObjectMightBeAccidentallyDuplicated(const VarDecl *Dcl);
4144	void DiagnoseUniqueObjectDuplication(const VarDecl *Dcl);
4145
4146	/// AddInitializerToDecl - Adds the initializer Init to the
4147	/// declaration dcl. If DirectInit is true, this is C++ direct
4148	/// initialization rather than copy initialization.
4149	void AddInitializerToDecl(Decl dcl, Expr init, bool DirectInit);
4150	void ActOnUninitializedDecl(Decl *dcl);
4151
4152	/// ActOnInitializerError - Given that there was an error parsing an
4153	/// initializer for the given declaration, try to at least re-establish
4154	/// invariants such as whether a variable's type is either dependent or
4155	/// complete.
4156	void ActOnInitializerError(Decl *Dcl);
4157
4158	void ActOnCXXForRangeDecl(Decl *D);
4159	StmtResult ActOnCXXForRangeIdentifier(Scope *S, SourceLocation IdentLoc,
4160	IdentifierInfo *Ident,
4161	ParsedAttributes &Attrs);
4162
4163	/// Check if VD needs to be dllexport/dllimport due to being in a
4164	/// dllexport/import function.
4165	void CheckStaticLocalForDllExport(VarDecl *VD);
4166	void CheckThreadLocalForLargeAlignment(VarDecl *VD);
4167
4168	/// FinalizeDeclaration - called by ParseDeclarationAfterDeclarator to perform
4169	/// any semantic actions necessary after any initializer has been attached.
4170	void FinalizeDeclaration(Decl *D);
4171	DeclGroupPtrTy FinalizeDeclaratorGroup(Scope S, const* DeclSpec &DS,
4172	ArrayRef<Decl *> Group);
4173
4174	/// BuildDeclaratorGroup - convert a list of declarations into a declaration
4175	/// group, performing any necessary semantic checking.
4176	DeclGroupPtrTy BuildDeclaratorGroup(MutableArrayRef<Decl *> Group);
4177
4178	/// Should be called on all declarations that might have attached
4179	/// documentation comments.
4180	void ActOnDocumentableDecl(Decl *D);
4181	void ActOnDocumentableDecls(ArrayRef<Decl *> Group);
4182
4183	enum class FnBodyKind {
4184	/// C++26 [dcl.fct.def.general]p1
4185	/// function-body:
4186	/// ctor-initializer[opt] compound-statement
4187	/// function-try-block
4188	Other,
4189	/// = default ;
4190	Default,
4191	/// deleted-function-body
4192	///
4193	/// deleted-function-body:
4194	/// = delete ;
4195	/// = delete ( unevaluated-string ) ;
4196	Delete
4197	};
4198
4199	void ActOnFinishKNRParamDeclarations(Scope *S, Declarator &D,
4200	SourceLocation LocAfterDecls);
4201	void CheckForFunctionRedefinition(
4202	FunctionDecl FD, const* FunctionDecl EffectiveDefinition = nullptr*,
4203	SkipBodyInfo SkipBody = nullptr*);
4204	Decl ActOnStartOfFunctionDef(Scope S, Declarator &D,
4205	MultiTemplateParamsArg TemplateParamLists,
4206	SkipBodyInfo SkipBody = nullptr*,
4207	FnBodyKind BodyKind = FnBodyKind::Other);
4208	Decl ActOnStartOfFunctionDef(Scope S, Decl *D,
4209	SkipBodyInfo SkipBody = nullptr*,
4210	FnBodyKind BodyKind = FnBodyKind::Other);
4211	void applyFunctionAttributesBeforeParsingBody(Decl *FD);
4212
4213	/// Determine whether we can delay parsing the body of a function or
4214	/// function template until it is used, assuming we don't care about emitting
4215	/// code for that function.
4216	///
4217	/// This will be \c false if we may need the body of the function in the
4218	/// middle of parsing an expression (where it's impractical to switch to
4219	/// parsing a different function), for instance, if it's constexpr in C++11
4220	/// or has an 'auto' return type in C++14. These cases are essentially bugs.
4221	bool canDelayFunctionBody(const Declarator &D);
4222
4223	/// Determine whether we can skip parsing the body of a function
4224	/// definition, assuming we don't care about analyzing its body or emitting
4225	/// code for that function.
4226	///
4227	/// This will be \c false only if we may need the body of the function in
4228	/// order to parse the rest of the program (for instance, if it is
4229	/// \c constexpr in C++11 or has an 'auto' return type in C++14).
4230	bool canSkipFunctionBody(Decl *D);
4231
4232	/// Given the set of return statements within a function body,
4233	/// compute the variables that are subject to the named return value
4234	/// optimization.
4235	///
4236	/// Each of the variables that is subject to the named return value
4237	/// optimization will be marked as NRVO variables in the AST, and any
4238	/// return statement that has a marked NRVO variable as its NRVO candidate can
4239	/// use the named return value optimization.
4240	///
4241	/// This function applies a very simplistic algorithm for NRVO: if every
4242	/// return statement in the scope of a variable has the same NRVO candidate,
4243	/// that candidate is an NRVO variable.
4244	void computeNRVO(Stmt Body, sema::FunctionScopeInfo Scope);
4245
4246	/// Performs semantic analysis at the end of a function body.
4247	///
4248	/// \param RetainFunctionScopeInfo If \c true, the client is responsible for
4249	/// releasing the associated \p FunctionScopeInfo. This is useful when
4250	/// building e.g. LambdaExprs.
4251	Decl ActOnFinishFunctionBody(Decl Decl, Stmt *Body,
4252	bool IsInstantiation = false,
4253	bool RetainFunctionScopeInfo = false);
4254	Decl ActOnSkippedFunctionBody(Decl Decl);
4255	void ActOnFinishInlineFunctionDef(FunctionDecl *D);
4256
4257	/// ActOnFinishDelayedAttribute - Invoked when we have finished parsing an
4258	/// attribute for which parsing is delayed.
4259	void ActOnFinishDelayedAttribute(Scope S, Decl D, ParsedAttributes &Attrs);
4260
4261	/// Diagnose any unused parameters in the given sequence of
4262	/// ParmVarDecl pointers.
4263	void DiagnoseUnusedParameters(ArrayRef<ParmVarDecl *> Parameters);
4264
4265	/// Diagnose whether the size of parameters or return value of a
4266	/// function or obj-c method definition is pass-by-value and larger than a
4267	/// specified threshold.
4268	void
4269	DiagnoseSizeOfParametersAndReturnValue(ArrayRef<ParmVarDecl *> Parameters,
4270	QualType ReturnTy, NamedDecl *D);
4271
4272	Decl ActOnFileScopeAsmDecl(Expr expr, SourceLocation AsmLoc,
4273	SourceLocation RParenLoc);
4274
4275	TopLevelStmtDecl ActOnStartTopLevelStmtDecl(Scope S);
4276	void ActOnFinishTopLevelStmtDecl(TopLevelStmtDecl D, Stmt Statement);
4277
4278	void ActOnPopScope(SourceLocation Loc, Scope *S);
4279
4280	/// ParsedFreeStandingDeclSpec - This method is invoked when a declspec with
4281	/// no declarator (e.g. "struct foo;") is parsed.
4282	Decl ParsedFreeStandingDeclSpec(Scope S, AccessSpecifier AS, DeclSpec &DS,
4283	const ParsedAttributesView &DeclAttrs,
4284	RecordDecl *&AnonRecord);
4285
4286	/// ParsedFreeStandingDeclSpec - This method is invoked when a declspec with
4287	/// no declarator (e.g. "struct foo;") is parsed. It also accepts template
4288	/// parameters to cope with template friend declarations.
4289	Decl ParsedFreeStandingDeclSpec(Scope S, AccessSpecifier AS, DeclSpec &DS,
4290	const ParsedAttributesView &DeclAttrs,
4291	MultiTemplateParamsArg TemplateParams,
4292	bool IsExplicitInstantiation,
4293	RecordDecl *&AnonRecord,
4294	SourceLocation EllipsisLoc = {});
4295
4296	/// BuildAnonymousStructOrUnion - Handle the declaration of an
4297	/// anonymous structure or union. Anonymous unions are a C++ feature
4298	/// (C++ [class.union]) and a C11 feature; anonymous structures
4299	/// are a C11 feature and GNU C++ extension.
4300	Decl BuildAnonymousStructOrUnion(Scope S, DeclSpec &DS, AccessSpecifier AS,
4301	RecordDecl *Record,
4302	const PrintingPolicy &Policy);
4303
4304	/// Called once it is known whether
4305	/// a tag declaration is an anonymous union or struct.
4306	void ActOnDefinedDeclarationSpecifier(Decl *D);
4307
4308	/// Emit diagnostic warnings for placeholder members.
4309	/// We can only do that after the class is fully constructed,
4310	/// as anonymous union/structs can insert placeholders
4311	/// in their parent scope (which might be a Record).
4312	void DiagPlaceholderFieldDeclDefinitions(RecordDecl *Record);
4313
4314	/// BuildMicrosoftCAnonymousStruct - Handle the declaration of an
4315	/// Microsoft C anonymous structure.
4316	/// Ref: http://msdn.microsoft.com/en-us/library/z2cx9y4f.aspx
4317	/// Example:
4318	///
4319	/// struct A { int a; };
4320	/// struct B { struct A; int b; };
4321	///
4322	/// void foo() {
4323	/// B var;
4324	/// var.a = 3;
4325	/// }
4326	Decl BuildMicrosoftCAnonymousStruct(Scope S, DeclSpec &DS,
4327	RecordDecl *Record);
4328
4329	/// Given a non-tag type declaration, returns an enum useful for indicating
4330	/// what kind of non-tag type this is.
4331	NonTagKind getNonTagTypeDeclKind(const Decl *D, TagTypeKind TTK);
4332
4333	/// Determine whether a tag with a given kind is acceptable
4334	/// as a redeclaration of the given tag declaration.
4335	///
4336	/// \returns true if the new tag kind is acceptable, false otherwise.
4337	bool isAcceptableTagRedeclaration(const TagDecl *Previous, TagTypeKind NewTag,
4338	bool isDefinition, SourceLocation NewTagLoc,
4339	const IdentifierInfo *Name);
4340
4341	/// This is invoked when we see 'struct foo' or 'struct {'. In the
4342	/// former case, Name will be non-null. In the later case, Name will be null.
4343	/// TagSpec indicates what kind of tag this is. TUK indicates whether this is
4344	/// a reference/declaration/definition of a tag.
4345	///
4346	/// \param IsTypeSpecifier \c true if this is a type-specifier (or
4347	/// trailing-type-specifier) other than one in an alias-declaration.
4348	///
4349	/// \param SkipBody If non-null, will be set to indicate if the caller should
4350	/// skip the definition of this tag and treat it as if it were a declaration.
4351	DeclResult ActOnTag(Scope S, unsigned* TagSpec, TagUseKind TUK,
4352	SourceLocation KWLoc, CXXScopeSpec &SS,
4353	IdentifierInfo *Name, SourceLocation NameLoc,
4354	const ParsedAttributesView &Attr, AccessSpecifier AS,
4355	SourceLocation ModulePrivateLoc,
4356	MultiTemplateParamsArg TemplateParameterLists,
4357	bool &OwnedDecl, bool &IsDependent,
4358	SourceLocation ScopedEnumKWLoc,
4359	bool ScopedEnumUsesClassTag, TypeResult UnderlyingType,
4360	bool IsTypeSpecifier, bool IsTemplateParamOrArg,
4361	OffsetOfKind OOK, SkipBodyInfo SkipBody = nullptr*);
4362
4363	/// ActOnField - Each field of a C struct/union is passed into this in order
4364	/// to create a FieldDecl object for it.
4365	Decl ActOnField(Scope S, Decl *TagD, SourceLocation DeclStart,
4366	Declarator &D, Expr *BitfieldWidth);
4367
4368	/// HandleField - Analyze a field of a C struct or a C++ data member.
4369	FieldDecl HandleField(Scope S, RecordDecl *TagD, SourceLocation DeclStart,
4370	Declarator &D, Expr *BitfieldWidth,
4371	InClassInitStyle InitStyle, AccessSpecifier AS);
4372
4373	/// Build a new FieldDecl and check its well-formedness.
4374	///
4375	/// This routine builds a new FieldDecl given the fields name, type,
4376	/// record, etc. \p PrevDecl should refer to any previous declaration
4377	/// with the same name and in the same scope as the field to be
4378	/// created.
4379	///
4380	/// \returns a new FieldDecl.
4381	///
4382	/// \todo The Declarator argument is a hack. It will be removed once
4383	FieldDecl *CheckFieldDecl(DeclarationName Name, QualType T,
4384	TypeSourceInfo TInfo, RecordDecl Record,
4385	SourceLocation Loc, bool Mutable,
4386	Expr *BitfieldWidth, InClassInitStyle InitStyle,
4387	SourceLocation TSSL, AccessSpecifier AS,
4388	NamedDecl PrevDecl, Declarator D = nullptr);
4389
4390	bool CheckNontrivialField(FieldDecl *FD);
4391
4392	/// ActOnLastBitfield - This routine handles synthesized bitfields rules for
4393	/// class and class extensions. For every class \@interface and class
4394	/// extension \@interface, if the last ivar is a bitfield of any type,
4395	/// then add an implicit `char :0` ivar to the end of that interface.
4396	void ActOnLastBitfield(SourceLocation DeclStart,
4397	SmallVectorImpl<Decl *> &AllIvarDecls);
4398
4399	// This is used for both record definitions and ObjC interface declarations.
4400	void ActOnFields(Scope S, SourceLocation RecLoc, Decl TagDecl,
4401	ArrayRef<Decl *> Fields, SourceLocation LBrac,
4402	SourceLocation RBrac, const ParsedAttributesView &AttrList);
4403
4404	/// ActOnTagStartDefinition - Invoked when we have entered the
4405	/// scope of a tag's definition (e.g., for an enumeration, class,
4406	/// struct, or union).
4407	void ActOnTagStartDefinition(Scope S, Decl TagDecl);
4408
4409	/// Perform ODR-like check for C/ObjC when merging tag types from modules.
4410	/// Differently from C++, actually parse the body and reject / error out
4411	/// in case of a structural mismatch.
4412	bool ActOnDuplicateDefinition(Scope S, Decl Prev, SkipBodyInfo &SkipBody);
4413
4414	typedef void *SkippedDefinitionContext;
4415
4416	/// Invoked when we enter a tag definition that we're skipping.
4417	SkippedDefinitionContext ActOnTagStartSkippedDefinition(Scope S, Decl TD);
4418
4419	/// ActOnStartCXXMemberDeclarations - Invoked when we have parsed a
4420	/// C++ record definition's base-specifiers clause and are starting its
4421	/// member declarations.
4422	void ActOnStartCXXMemberDeclarations(Scope S, Decl TagDecl,
4423	SourceLocation FinalLoc,
4424	bool IsFinalSpelledSealed,
4425	bool IsAbstract,
4426	SourceLocation LBraceLoc);
4427
4428	/// ActOnTagFinishDefinition - Invoked once we have finished parsing
4429	/// the definition of a tag (enumeration, class, struct, or union).
4430	void ActOnTagFinishDefinition(Scope S, Decl TagDecl,
4431	SourceRange BraceRange);
4432
4433	ASTContext::CXXRecordDeclRelocationInfo
4434	CheckCXX2CRelocatable(const clang::CXXRecordDecl *D);
4435
4436	void ActOnTagFinishSkippedDefinition(SkippedDefinitionContext Context);
4437
4438	/// ActOnTagDefinitionError - Invoked when there was an unrecoverable
4439	/// error parsing the definition of a tag.
4440	void ActOnTagDefinitionError(Scope S, Decl TagDecl);
4441
4442	EnumConstantDecl CheckEnumConstant(EnumDecl Enum,
4443	EnumConstantDecl *LastEnumConst,
4444	SourceLocation IdLoc, IdentifierInfo *Id,
4445	Expr *val);
4446
4447	/// Check that this is a valid underlying type for an enum declaration.
4448	bool CheckEnumUnderlyingType(TypeSourceInfo *TI);
4449
4450	/// Check whether this is a valid redeclaration of a previous enumeration.
4451	/// \return true if the redeclaration was invalid.
4452	bool CheckEnumRedeclaration(SourceLocation EnumLoc, bool IsScoped,
4453	QualType EnumUnderlyingTy, bool IsFixed,
4454	const EnumDecl *Prev);
4455
4456	/// Determine whether the body of an anonymous enumeration should be skipped.
4457	/// \param II The name of the first enumerator.
4458	SkipBodyInfo shouldSkipAnonEnumBody(Scope S, IdentifierInfo II,
4459	SourceLocation IILoc);
4460
4461	Decl ActOnEnumConstant(Scope S, Decl EnumDecl, Decl LastEnumConstant,
4462	SourceLocation IdLoc, IdentifierInfo *Id,
4463	const ParsedAttributesView &Attrs,
4464	SourceLocation EqualLoc, Expr *Val,
4465	SkipBodyInfo SkipBody = nullptr*);
4466	void ActOnEnumBody(SourceLocation EnumLoc, SourceRange BraceRange,
4467	Decl EnumDecl, ArrayRef<Decl > Elements, Scope *S,
4468	const ParsedAttributesView &Attr);
4469
4470	/// Set the current declaration context until it gets popped.
4471	void PushDeclContext(Scope S, DeclContext DC);
4472	void PopDeclContext();
4473
4474	/// EnterDeclaratorContext - Used when we must lookup names in the context
4475	/// of a declarator's nested name specifier.
4476	void EnterDeclaratorContext(Scope S, DeclContext DC);
4477	void ExitDeclaratorContext(Scope *S);
4478
4479	/// Enter a template parameter scope, after it's been associated with a
4480	/// particular DeclContext. Causes lookup within the scope to chain through
4481	/// enclosing contexts in the correct order.
4482	void EnterTemplatedContext(Scope S, DeclContext DC);
4483
4484	/// Push the parameters of D, which must be a function, into scope.
4485	void ActOnReenterFunctionContext(Scope S, Decl D);
4486	void ActOnExitFunctionContext();
4487
4488	/// Add this decl to the scope shadowed decl chains.
4489	void PushOnScopeChains(NamedDecl D, Scope S, bool AddToContext = true);
4490
4491	/// isDeclInScope - If 'Ctx' is a function/method, isDeclInScope returns true
4492	/// if 'D' is in Scope 'S', otherwise 'S' is ignored and isDeclInScope returns
4493	/// true if 'D' belongs to the given declaration context.
4494	///
4495	/// \param AllowInlineNamespace If \c true, allow the declaration to be in the
4496	/// enclosing namespace set of the context, rather than contained
4497	/// directly within it.
4498	bool isDeclInScope(NamedDecl D, DeclContext Ctx, Scope S = nullptr*,
4499	bool AllowInlineNamespace = false) const;
4500
4501	/// Finds the scope corresponding to the given decl context, if it
4502	/// happens to be an enclosing scope. Otherwise return NULL.
4503	static Scope getScopeForDeclContext(Scope S, DeclContext *DC);
4504
4505	/// Subroutines of ActOnDeclarator().
4506	TypedefDecl ParseTypedefDecl(Scope S, Declarator &D, QualType T,
4507	TypeSourceInfo *TInfo);
4508	bool isIncompatibleTypedef(const TypeDecl Old, TypedefNameDecl New);
4509
4510	/// mergeDeclAttributes - Copy attributes from the Old decl to the New one.
4511	void mergeDeclAttributes(
4512	NamedDecl New, Decl Old,
4513	AvailabilityMergeKind AMK = AvailabilityMergeKind::Redeclaration);
4514
4515	/// CheckAttributesOnDeducedType - Calls Sema functions for attributes that
4516	/// requires the type to be deduced.
4517	void CheckAttributesOnDeducedType(Decl *D);
4518
4519	/// MergeTypedefNameDecl - We just parsed a typedef 'New' which has the
4520	/// same name and scope as a previous declaration 'Old'. Figure out
4521	/// how to resolve this situation, merging decls or emitting
4522	/// diagnostics as appropriate. If there was an error, set New to be invalid.
4523	void MergeTypedefNameDecl(Scope S, TypedefNameDecl New,
4524	LookupResult &OldDecls);
4525
4526	/// CleanupMergedEnum - We have just merged the decl 'New' by making another
4527	/// definition visible.
4528	/// This method performs any necessary cleanup on the parser state to discard
4529	/// child nodes from newly parsed decl we are retiring.
4530	void CleanupMergedEnum(Scope S, Decl New);
4531
4532	/// MergeFunctionDecl - We just parsed a function 'New' from
4533	/// declarator D which has the same name and scope as a previous
4534	/// declaration 'Old'. Figure out how to resolve this situation,
4535	/// merging decls or emitting diagnostics as appropriate.
4536	///
4537	/// In C++, New and Old must be declarations that are not
4538	/// overloaded. Use IsOverload to determine whether New and Old are
4539	/// overloaded, and to select the Old declaration that New should be
4540	/// merged with.
4541	///
4542	/// Returns true if there was an error, false otherwise.
4543	bool MergeFunctionDecl(FunctionDecl New, NamedDecl &Old, Scope *S,
4544	bool MergeTypeWithOld, bool NewDeclIsDefn);
4545
4546	/// Completes the merge of two function declarations that are
4547	/// known to be compatible.
4548	///
4549	/// This routine handles the merging of attributes and other
4550	/// properties of function declarations from the old declaration to
4551	/// the new declaration, once we know that New is in fact a
4552	/// redeclaration of Old.
4553	///
4554	/// \returns false
4555	bool MergeCompatibleFunctionDecls(FunctionDecl New, FunctionDecl Old,
4556	Scope S, bool* MergeTypeWithOld);
4557	void mergeObjCMethodDecls(ObjCMethodDecl New, ObjCMethodDecl Old);
4558
4559	/// MergeVarDecl - We just parsed a variable 'New' which has the same name
4560	/// and scope as a previous declaration 'Old'. Figure out how to resolve this
4561	/// situation, merging decls or emitting diagnostics as appropriate.
4562	///
4563	/// Tentative definition rules (C99 6.9.2p2) are checked by
4564	/// FinalizeDeclaratorGroup. Unfortunately, we can't analyze tentative
4565	/// definitions here, since the initializer hasn't been attached.
4566	void MergeVarDecl(VarDecl *New, LookupResult &Previous);
4567
4568	/// MergeVarDeclTypes - We parsed a variable 'New' which has the same name and
4569	/// scope as a previous declaration 'Old'. Figure out how to merge their
4570	/// types, emitting diagnostics as appropriate.
4571	///
4572	/// Declarations using the auto type specifier (C++ [decl.spec.auto]) call
4573	/// back to here in AddInitializerToDecl. We can't check them before the
4574	/// initializer is attached.
4575	void MergeVarDeclTypes(VarDecl New, VarDecl Old, bool MergeTypeWithOld);
4576
4577	/// We've just determined that \p Old and \p New both appear to be definitions
4578	/// of the same variable. Either diagnose or fix the problem.
4579	bool checkVarDeclRedefinition(VarDecl OldDefn, VarDecl NewDefn);
4580	void notePreviousDefinition(const NamedDecl *Old, SourceLocation New);
4581
4582	/// Filters out lookup results that don't fall within the given scope
4583	/// as determined by isDeclInScope.
4584	void FilterLookupForScope(LookupResult &R, DeclContext Ctx, Scope S,
4585	bool ConsiderLinkage, bool AllowInlineNamespace);
4586
4587	/// We've determined that \p New is a redeclaration of \p Old. Check that they
4588	/// have compatible owning modules.
4589	bool CheckRedeclarationModuleOwnership(NamedDecl New, NamedDecl Old);
4590
4591	/// [module.interface]p6:
4592	/// A redeclaration of an entity X is implicitly exported if X was introduced
4593	/// by an exported declaration; otherwise it shall not be exported.
4594	bool CheckRedeclarationExported(NamedDecl New, NamedDecl Old);
4595
4596	/// A wrapper function for checking the semantic restrictions of
4597	/// a redeclaration within a module.
4598	bool CheckRedeclarationInModule(NamedDecl New, NamedDecl Old);
4599
4600	/// Check the redefinition in C++20 Modules.
4601	///
4602	/// [basic.def.odr]p14:
4603	/// For any definable item D with definitions in multiple translation units,
4604	/// - if D is a non-inline non-templated function or variable, or
4605	/// - if the definitions in different translation units do not satisfy the
4606	/// following requirements,
4607	/// the program is ill-formed; a diagnostic is required only if the
4608	/// definable item is attached to a named module and a prior definition is
4609	/// reachable at the point where a later definition occurs.
4610	/// - Each such definition shall not be attached to a named module
4611	/// ([module.unit]).
4612	/// - Each such definition shall consist of the same sequence of tokens, ...
4613	/// ...
4614	///
4615	/// Return true if the redefinition is not allowed. Return false otherwise.
4616	bool IsRedefinitionInModule(const NamedDecl New, const* NamedDecl Old) const*;
4617
4618	bool ShouldWarnIfUnusedFileScopedDecl(const DeclaratorDecl D) const*;
4619
4620	/// If it's a file scoped decl that must warn if not used, keep track
4621	/// of it.
4622	void MarkUnusedFileScopedDecl(const DeclaratorDecl *D);
4623
4624	typedef llvm::function_ref<void(SourceLocation Loc, PartialDiagnostic PD)>
4625	DiagReceiverTy;
4626
4627	void DiagnoseUnusedNestedTypedefs(const RecordDecl *D);
4628	void DiagnoseUnusedNestedTypedefs(const RecordDecl *D,
4629	DiagReceiverTy DiagReceiver);
4630	void DiagnoseUnusedDecl(const NamedDecl *ND);
4631
4632	/// DiagnoseUnusedDecl - Emit warnings about declarations that are not used
4633	/// unless they are marked attr(unused).
4634	void DiagnoseUnusedDecl(const NamedDecl *ND, DiagReceiverTy DiagReceiver);
4635
4636	/// If VD is set but not otherwise used, diagnose, for a parameter or a
4637	/// variable.
4638	void DiagnoseUnusedButSetDecl(const VarDecl *VD, DiagReceiverTy DiagReceiver);
4639
4640	/// getNonFieldDeclScope - Retrieves the innermost scope, starting
4641	/// from S, where a non-field would be declared. This routine copes
4642	/// with the difference between C and C++ scoping rules in structs and
4643	/// unions. For example, the following code is well-formed in C but
4644	/// ill-formed in C++:
4645	/// @code
4646	/// struct S6 {
4647	/// enum { BAR } e;
4648	/// };
4649	///
4650	/// void test_S6() {
4651	/// struct S6 a;
4652	/// a.e = BAR;
4653	/// }
4654	/// @endcode
4655	/// For the declaration of BAR, this routine will return a different
4656	/// scope. The scope S will be the scope of the unnamed enumeration
4657	/// within S6. In C++, this routine will return the scope associated
4658	/// with S6, because the enumeration's scope is a transparent
4659	/// context but structures can contain non-field names. In C, this
4660	/// routine will return the translation unit scope, since the
4661	/// enumeration's scope is a transparent context and structures cannot
4662	/// contain non-field names.
4663	Scope getNonFieldDeclScope(Scope S);
4664
4665	FunctionDecl CreateBuiltin(IdentifierInfo II, QualType Type, unsigned ID,
4666	SourceLocation Loc);
4667
4668	/// LazilyCreateBuiltin - The specified Builtin-ID was first used at
4669	/// file scope. lazily create a decl for it. ForRedeclaration is true
4670	/// if we're creating this built-in in anticipation of redeclaring the
4671	/// built-in.
4672	NamedDecl LazilyCreateBuiltin(IdentifierInfo II, unsigned ID, Scope *S,
4673	bool ForRedeclaration, SourceLocation Loc);
4674
4675	/// Get the outermost AttributedType node that sets a calling convention.
4676	/// Valid types should not have multiple attributes with different CCs.
4677	const AttributedType getCallingConvAttributedType(QualType T) const*;
4678
4679	/// GetNameForDeclarator - Determine the full declaration name for the
4680	/// given Declarator.
4681	DeclarationNameInfo GetNameForDeclarator(Declarator &D);
4682
4683	/// Retrieves the declaration name from a parsed unqualified-id.
4684	DeclarationNameInfo GetNameFromUnqualifiedId(const UnqualifiedId &Name);
4685
4686	/// ParsingInitForAutoVars - a set of declarations with auto types for which
4687	/// we are currently parsing the initializer.
4688	llvm::SmallPtrSet<const Decl *, `4`> ParsingInitForAutoVars;
4689
4690	/// Look for a locally scoped extern "C" declaration by the given name.
4691	NamedDecl *findLocallyScopedExternCDecl(DeclarationName Name);
4692
4693	void deduceOpenCLAddressSpace(VarDecl *decl);
4694	void deduceHLSLAddressSpace(VarDecl *decl);
4695
4696	/// Adjust the \c DeclContext for a function or variable that might be a
4697	/// function-local external declaration.
4698	static bool adjustContextForLocalExternDecl(DeclContext *&DC);
4699
4700	void MarkTypoCorrectedFunctionDefinition(const NamedDecl *F);
4701
4702	/// Checks if the variant/multiversion functions are compatible.
4703	bool areMultiversionVariantFunctionsCompatible(
4704	const FunctionDecl OldFD, const* FunctionDecl *NewFD,
4705	const PartialDiagnostic &NoProtoDiagID,
4706	const PartialDiagnosticAt &NoteCausedDiagIDAt,
4707	const PartialDiagnosticAt &NoSupportDiagIDAt,
4708	const PartialDiagnosticAt &DiffDiagIDAt, bool TemplatesSupported,
4709	bool ConstexprSupported, bool CLinkageMayDiffer);
4710
4711	/// type checking declaration initializers (C99 6.7.8)
4712	bool CheckForConstantInitializer(
4713	Expr Init, unsigned* DiagID = diag::err_init_element_not_constant);
4714
4715	QualType deduceVarTypeFromInitializer(VarDecl *VDecl, DeclarationName Name,
4716	QualType Type, TypeSourceInfo *TSI,
4717	SourceRange Range, bool DirectInit,
4718	Expr *Init);
4719
4720	bool DeduceVariableDeclarationType(VarDecl VDecl, bool* DirectInit,
4721	Expr *Init);
4722
4723	sema::LambdaScopeInfo RebuildLambdaScopeInfo(CXXMethodDecl CallOperator);
4724
4725	// Heuristically tells if the function is `get_return_object` member of a
4726	// coroutine promise_type by matching the function name.
4727	static bool CanBeGetReturnObject(const FunctionDecl *FD);
4728	static bool CanBeGetReturnTypeOnAllocFailure(const FunctionDecl *FD);
4729
4730	/// ImplicitlyDefineFunction - An undeclared identifier was used in a function
4731	/// call, forming a call to an implicitly defined function (per C99 6.5.1p2).
4732	NamedDecl *ImplicitlyDefineFunction(SourceLocation Loc, IdentifierInfo &II,
4733	Scope *S);
4734
4735	/// If this function is a C++ replaceable global allocation function
4736	/// (C++2a [basic.stc.dynamic.allocation], C++2a [new.delete]),
4737	/// adds any function attributes that we know a priori based on the standard.
4738	///
4739	/// We need to check for duplicate attributes both here and where user-written
4740	/// attributes are applied to declarations.
4741	void AddKnownFunctionAttributesForReplaceableGlobalAllocationFunction(
4742	FunctionDecl *FD);
4743
4744	/// Adds any function attributes that we know a priori based on
4745	/// the declaration of this function.
4746	///
4747	/// These attributes can apply both to implicitly-declared builtins
4748	/// (like __builtin___printf_chk) or to library-declared functions
4749	/// like NSLog or printf.
4750	///
4751	/// We need to check for duplicate attributes both here and where user-written
4752	/// attributes are applied to declarations.
4753	void AddKnownFunctionAttributes(FunctionDecl *FD);
4754
4755	/// VerifyBitField - verifies that a bit field expression is an ICE and has
4756	/// the correct width, and that the field type is valid.
4757	/// Returns false on success.
4758	ExprResult VerifyBitField(SourceLocation FieldLoc,
4759	const IdentifierInfo *FieldName, QualType FieldTy,
4760	bool IsMsStruct, Expr *BitWidth);
4761
4762	/// IsValueInFlagEnum - Determine if a value is allowed as part of a flag
4763	/// enum. If AllowMask is true, then we also allow the complement of a valid
4764	/// value, to be used as a mask.
4765	bool IsValueInFlagEnum(const EnumDecl ED, const* llvm::APInt &Val,
4766	bool AllowMask) const;
4767
4768	/// ActOnPragmaWeakID - Called on well formed \#pragma weak ident.
4769	void ActOnPragmaWeakID(IdentifierInfo *WeakName, SourceLocation PragmaLoc,
4770	SourceLocation WeakNameLoc);
4771
4772	/// ActOnPragmaRedefineExtname - Called on well formed
4773	/// \#pragma redefine_extname oldname newname.
4774	void ActOnPragmaRedefineExtname(IdentifierInfo *WeakName,
4775	IdentifierInfo *AliasName,
4776	SourceLocation PragmaLoc,
4777	SourceLocation WeakNameLoc,
4778	SourceLocation AliasNameLoc);
4779
4780	/// ActOnPragmaWeakAlias - Called on well formed \#pragma weak ident = ident.
4781	void ActOnPragmaWeakAlias(IdentifierInfo WeakName, IdentifierInfo AliasName,
4782	SourceLocation PragmaLoc,
4783	SourceLocation WeakNameLoc,
4784	SourceLocation AliasNameLoc);
4785
4786	/// Status of the function emission on the CUDA/HIP/OpenMP host/device attrs.
4787	enum class FunctionEmissionStatus {
4788	Emitted,
4789	CUDADiscarded, // Discarded due to CUDA/HIP hostness
4790	OMPDiscarded, // Discarded due to OpenMP hostness
4791	TemplateDiscarded, // Discarded due to uninstantiated templates
4792	Unknown,
4793	};
4794	FunctionEmissionStatus getEmissionStatus(const FunctionDecl *Decl,
4795	bool Final = false);
4796
4797	// Whether the callee should be ignored in CUDA/HIP/OpenMP host/device check.
4798	bool shouldIgnoreInHostDeviceCheck(FunctionDecl *Callee);
4799
4800	/// Function or variable declarations to be checked for whether the deferred
4801	/// diagnostics should be emitted.
4802	llvm::SmallSetVector<Decl *, `4`> DeclsToCheckForDeferredDiags;
4803
4804	private:
4805	/// Map of current shadowing declarations to shadowed declarations. Warn if
4806	/// it looks like the user is trying to modify the shadowing declaration.
4807	llvm::DenseMap<const NamedDecl , const* NamedDecl *> ShadowingDecls;
4808
4809	// We need this to handle
4810	//
4811	// typedef struct {
4812	// void foo() { return 0; }*
4813	// } A;
4814	//
4815	// When we see foo we don't know if after the typedef we will get 'A' or 'A'*
4816	// for example. If 'A', foo will have external linkage. If we have 'A',*
4817	// foo will have no linkage. Since we can't know until we get to the end
4818	// of the typedef, this function finds out if D might have non-external
4819	// linkage. Callers should verify at the end of the TU if it D has external
4820	// linkage or not.
4821	static bool mightHaveNonExternalLinkage(const DeclaratorDecl *FD);
4822
4823	#include "clang/Sema/AttrIsTypeDependent.inc"
4824
4825	///@}
4826
4827	//
4828	//
4829	// -------------------------------------------------------------------------
4830	//
4831	//
4832
4833	/// \name Declaration Attribute Handling
4834	/// Implementations are in SemaDeclAttr.cpp
4835	///@{
4836
4837	public:
4838	/// Describes the kind of priority given to an availability attribute.
4839	///
4840	/// The sum of priorities deteremines the final priority of the attribute.
4841	/// The final priority determines how the attribute will be merged.
4842	/// An attribute with a lower priority will always remove higher priority
4843	/// attributes for the specified platform when it is being applied. An
4844	/// attribute with a higher priority will not be applied if the declaration
4845	/// already has an availability attribute with a lower priority for the
4846	/// specified platform. The final prirority values are not expected to match
4847	/// the values in this enumeration, but instead should be treated as a plain
4848	/// integer value. This enumeration just names the priority weights that are
4849	/// used to calculate that final vaue.
4850	enum AvailabilityPriority : int {
4851	/// The availability attribute was specified explicitly next to the
4852	/// declaration.
4853	AP_Explicit = `0`,
4854
4855	/// The availability attribute was applied using '#pragma clang attribute'.
4856	AP_PragmaClangAttribute = `1`,
4857
4858	/// The availability attribute for a specific platform was inferred from
4859	/// an availability attribute for another platform.
4860	AP_InferredFromOtherPlatform = `2`
4861	};
4862
4863	/// Describes the reason a calling convention specification was ignored, used
4864	/// for diagnostics.
4865	enum class CallingConventionIgnoredReason {
4866	ForThisTarget = `0`,
4867	VariadicFunction,
4868	ConstructorDestructor,
4869	BuiltinFunction
4870	};
4871
4872	/// A helper function to provide Attribute Location for the Attr types
4873	/// AND the ParsedAttr.
4874	template <typename AttrInfo>
4875	static std::enable_if_t<std::is_base_of_v<Attr, AttrInfo>, SourceLocation>
4876	getAttrLoc(const AttrInfo &AL) {
4877	return AL.getLocation();
4878	}
4879	SourceLocation getAttrLoc(const AttributeCommonInfo &CI);
4880
4881	/// If Expr is a valid integer constant, get the value of the integer
4882	/// expression and return success or failure. May output an error.
4883	///
4884	/// Negative argument is implicitly converted to unsigned, unless
4885	/// \p StrictlyUnsigned is true.
4886	template <typename AttrInfo>
4887	bool checkUInt32Argument(const AttrInfo &AI, const Expr *Expr, uint32_t &Val,
4888	unsigned Idx = UINT_MAX,
4889	bool StrictlyUnsigned = false) {
4890	std::optional<llvm::APSInt> I = llvm::APSInt (`32`);
4891	if (Expr->isTypeDependent() \|\|
4892	!(I = Expr->getIntegerConstantExpr(Ctx: Context))) {
4893	if (Idx != UINT_MAX)
4894	Diag(getAttrLoc(AI), diag::err_attribute_argument_n_type)
4895	<< &AI << Idx << AANT_ArgumentIntegerConstant
4896	<< Expr->getSourceRange();
4897	else
4898	Diag(getAttrLoc(AI), diag::err_attribute_argument_type)
4899	<< &AI << AANT_ArgumentIntegerConstant << Expr->getSourceRange();
4900	return false;
4901	}
4902
4903	if (!I ->isIntN(N: `32`)) {
4904	Diag(Loc: Expr->getExprLoc(), DiagID: diag::err_ice_too_large)
4905	<< toString(I: I, Radix: `10`, Signed: false) << `32` << /* Unsigned / `1`;
4906	return false;
4907	}
4908
4909	if (StrictlyUnsigned && I ->isSigned() && I ->isNegative()) {
4910	Diag(getAttrLoc(AI), diag::err_attribute_requires_positive_integer)
4911	<< &AI << /non-negative/ `1`;
4912	return false;
4913	}
4914
4915	Val = (uint32_t)I ->getZExtValue();
4916	return true;
4917	}
4918
4919	/// WeakTopLevelDecl - Translation-unit scoped declarations generated by
4920	/// \#pragma weak during processing of other Decls.
4921	/// I couldn't figure out a clean way to generate these in-line, so
4922	/// we store them here and handle separately -- which is a hack.
4923	/// It would be best to refactor this.
4924	SmallVector<Decl *, `2`> WeakTopLevelDecl;
4925
4926	/// WeakTopLevelDeclDecls - access to \#pragma weak-generated Decls
4927	SmallVectorImpl<Decl > &WeakTopLevelDecls() { return* WeakTopLevelDecl; }
4928
4929	typedef LazyVector<TypedefNameDecl *, ExternalSemaSource,
4930	&ExternalSemaSource::ReadExtVectorDecls, `2`, `2`>
4931	ExtVectorDeclsType;
4932
4933	/// ExtVectorDecls - This is a list all the extended vector types. This allows
4934	/// us to associate a raw vector type with one of the ext_vector type names.
4935	/// This is only necessary for issuing pretty diagnostics.
4936	ExtVectorDeclsType ExtVectorDecls;
4937
4938	/// Check if the argument \p E is a ASCII string literal. If not emit an error
4939	/// and return false, otherwise set \p Str to the value of the string literal
4940	/// and return true.
4941	bool checkStringLiteralArgumentAttr(const AttributeCommonInfo &CI,
4942	const Expr *E, StringRef &Str,
4943	SourceLocation ArgLocation = nullptr*);
4944
4945	/// Check if the argument \p ArgNum of \p Attr is a ASCII string literal.
4946	/// If not emit an error and return false. If the argument is an identifier it
4947	/// will emit an error with a fixit hint and treat it as if it was a string
4948	/// literal.
4949	bool checkStringLiteralArgumentAttr(const ParsedAttr &Attr, unsigned ArgNum,
4950	StringRef &Str,
4951	SourceLocation ArgLocation = nullptr*);
4952
4953	/// Determine if type T is a valid subject for a nonnull and similar
4954	/// attributes. Dependent types are considered valid so they can be checked
4955	/// during instantiation time. By default, we look through references (the
4956	/// behavior used by nonnull), but if the second parameter is true, then we
4957	/// treat a reference type as valid.
4958	bool isValidPointerAttrType(QualType T, bool RefOkay = false);
4959
4960	/// AddAssumeAlignedAttr - Adds an assume_aligned attribute to a particular
4961	/// declaration.
4962	void AddAssumeAlignedAttr(Decl D, const* AttributeCommonInfo &CI, Expr *E,
4963	Expr *OE);
4964
4965	/// AddAllocAlignAttr - Adds an alloc_align attribute to a particular
4966	/// declaration.
4967	void AddAllocAlignAttr(Decl D, const* AttributeCommonInfo &CI,
4968	Expr *ParamExpr);
4969
4970	bool CheckAttrTarget(const ParsedAttr &CurrAttr);
4971	bool CheckAttrNoArgs(const ParsedAttr &CurrAttr);
4972
4973	AvailabilityAttr *
4974	mergeAvailabilityAttr(NamedDecl D, const* AttributeCommonInfo &CI,
4975	const IdentifierInfo Platform, bool* Implicit,
4976	VersionTuple Introduced, VersionTuple Deprecated,
4977	VersionTuple Obsoleted, bool IsUnavailable,
4978	StringRef Message, bool IsStrict, StringRef Replacement,
4979	AvailabilityMergeKind AMK, int Priority,
4980	const IdentifierInfo *IIEnvironment);
4981
4982	TypeVisibilityAttr *
4983	mergeTypeVisibilityAttr(Decl D, const* AttributeCommonInfo &CI,
4984	TypeVisibilityAttr::VisibilityType Vis);
4985	VisibilityAttr mergeVisibilityAttr(Decl D, const AttributeCommonInfo &CI,
4986	VisibilityAttr::VisibilityType Vis);
4987	void mergeVisibilityType(Decl *D, SourceLocation Loc,
4988	VisibilityAttr::VisibilityType Type);
4989	SectionAttr mergeSectionAttr(Decl D, const AttributeCommonInfo &CI,
4990	StringRef Name);
4991
4992	/// Used to implement to perform semantic checking on
4993	/// attribute((section("foo"))) specifiers.
4994	///
4995	/// In this case, "foo" is passed in to be checked. If the section
4996	/// specifier is invalid, return an Error that indicates the problem.
4997	///
4998	/// This is a simple quality of implementation feature to catch errors
4999	/// and give good diagnostics in cases when the assembler or code generator
5000	/// would otherwise reject the section specifier.
5001	llvm::Error isValidSectionSpecifier(StringRef Str);
5002	bool checkSectionName(SourceLocation LiteralLoc, StringRef Str);
5003	CodeSegAttr mergeCodeSegAttr(Decl D, const AttributeCommonInfo &CI,
5004	StringRef Name);
5005
5006	// Check for things we'd like to warn about. Multiversioning issues are
5007	// handled later in the process, once we know how many exist.
5008	bool checkTargetAttr(SourceLocation LiteralLoc, StringRef Str);
5009
5010	ErrorAttr mergeErrorAttr(Decl D, const AttributeCommonInfo &CI,
5011	StringRef NewUserDiagnostic);
5012	FormatAttr mergeFormatAttr(Decl D, const AttributeCommonInfo &CI,
5013	const IdentifierInfo Format, int* FormatIdx,
5014	int FirstArg);
5015	FormatMatchesAttr mergeFormatMatchesAttr(Decl D,
5016	const AttributeCommonInfo &CI,
5017	const IdentifierInfo *Format,
5018	int FormatIdx,
5019	StringLiteral *FormatStr);
5020	ModularFormatAttr mergeModularFormatAttr(Decl D,
5021	const AttributeCommonInfo &CI,
5022	const IdentifierInfo *ModularImplFn,
5023	StringRef ImplName,
5024	MutableArrayRef<StringRef> Aspects);
5025
5026	/// AddAlignedAttr - Adds an aligned attribute to a particular declaration.
5027	void AddAlignedAttr(Decl D, const* AttributeCommonInfo &CI, Expr *E,
5028	bool IsPackExpansion);
5029	void AddAlignedAttr(Decl D, const* AttributeCommonInfo &CI, TypeSourceInfo *T,
5030	bool IsPackExpansion);
5031
5032	/// AddAlignValueAttr - Adds an align_value attribute to a particular
5033	/// declaration.
5034	void AddAlignValueAttr(Decl D, const* AttributeCommonInfo &CI, Expr *E);
5035
5036	/// CreateAnnotationAttr - Creates an annotation Annot with Args arguments.
5037	Attr CreateAnnotationAttr(const* AttributeCommonInfo &CI, StringRef Annot,
5038	MutableArrayRef<Expr *> Args);
5039	Attr CreateAnnotationAttr(const* ParsedAttr &AL);
5040
5041	bool checkMSInheritanceAttrOnDefinition(CXXRecordDecl *RD, SourceRange Range,
5042	bool BestCase,
5043	MSInheritanceModel SemanticSpelling);
5044
5045	void CheckAlignasUnderalignment(Decl *D);
5046
5047	/// AddModeAttr - Adds a mode attribute to a particular declaration.
5048	void AddModeAttr(Decl D, const* AttributeCommonInfo &CI,
5049	const IdentifierInfo Name, bool* InInstantiation = false);
5050	AlwaysInlineAttr mergeAlwaysInlineAttr(Decl D,
5051	const AttributeCommonInfo &CI,
5052	const IdentifierInfo *Ident);
5053	MinSizeAttr mergeMinSizeAttr(Decl D, const AttributeCommonInfo &CI);
5054	OptimizeNoneAttr mergeOptimizeNoneAttr(Decl D,
5055	const AttributeCommonInfo &CI);
5056	InternalLinkageAttr mergeInternalLinkageAttr(Decl D, const ParsedAttr &AL);
5057	InternalLinkageAttr mergeInternalLinkageAttr(Decl D,
5058	const InternalLinkageAttr &AL);
5059
5060	/// Check validaty of calling convention attribute \p attr. If \p FD
5061	/// is not null pointer, use \p FD to determine the CUDA/HIP host/device
5062	/// target. Otherwise, it is specified by \p CFT.
5063	bool CheckCallingConvAttr(
5064	const ParsedAttr &attr, CallingConv &CC, const FunctionDecl FD = nullptr*,
5065	CUDAFunctionTarget CFT = CUDAFunctionTarget::InvalidTarget);
5066
5067	/// Checks a regparm attribute, returning true if it is ill-formed and
5068	/// otherwise setting numParams to the appropriate value.
5069	bool CheckRegparmAttr(const ParsedAttr &attr, unsigned &value);
5070
5071	/// Create an CUDALaunchBoundsAttr attribute.
5072	CUDALaunchBoundsAttr CreateLaunchBoundsAttr(const* AttributeCommonInfo &CI,
5073	Expr *MaxThreads,
5074	Expr *MinBlocks,
5075	Expr *MaxBlocks);
5076
5077	/// AddLaunchBoundsAttr - Adds a launch_bounds attribute to a particular
5078	/// declaration.
5079	void AddLaunchBoundsAttr(Decl D, const* AttributeCommonInfo &CI,
5080	Expr MaxThreads, Expr MinBlocks, Expr *MaxBlocks);
5081
5082	/// Add a cluster_dims attribute to a particular declaration.
5083	CUDAClusterDimsAttr createClusterDimsAttr(const* AttributeCommonInfo &CI,
5084	Expr X, Expr Y, Expr *Z);
5085	void addClusterDimsAttr(Decl D, const* AttributeCommonInfo &CI, Expr *X,
5086	Expr Y, Expr Z);
5087	/// Add a no_cluster attribute to a particular declaration.
5088	void addNoClusterAttr(Decl D, const* AttributeCommonInfo &CI);
5089
5090	enum class RetainOwnershipKind { NS, CF, OS };
5091
5092	UuidAttr mergeUuidAttr(Decl D, const AttributeCommonInfo &CI,
5093	StringRef UuidAsWritten, MSGuidDecl *GuidDecl);
5094
5095	BTFDeclTagAttr mergeBTFDeclTagAttr(Decl D, const BTFDeclTagAttr &AL);
5096
5097	DLLImportAttr mergeDLLImportAttr(Decl D, const AttributeCommonInfo &CI);
5098	DLLExportAttr mergeDLLExportAttr(Decl D, const AttributeCommonInfo &CI);
5099	MSInheritanceAttr mergeMSInheritanceAttr(Decl D,
5100	const AttributeCommonInfo &CI,
5101	bool BestCase,
5102	MSInheritanceModel Model);
5103
5104	EnforceTCBAttr mergeEnforceTCBAttr(Decl D, const EnforceTCBAttr &AL);
5105	EnforceTCBLeafAttr mergeEnforceTCBLeafAttr(Decl D,
5106	const EnforceTCBLeafAttr &AL);
5107
5108	/// Helper for delayed processing TransparentUnion or
5109	/// BPFPreserveAccessIndexAttr attribute.
5110	void ProcessDeclAttributeDelayed(Decl *D,
5111	const ParsedAttributesView &AttrList);
5112
5113	// Options for ProcessDeclAttributeList().
5114	struct ProcessDeclAttributeOptions {
5115	ProcessDeclAttributeOptions()
5116	: IncludeCXX11Attributes(true), IgnoreTypeAttributes(false) {}
5117
5118	ProcessDeclAttributeOptions WithIncludeCXX11Attributes(bool Val) {
5119	ProcessDeclAttributeOptions Result = *this;
5120	Result.IncludeCXX11Attributes = Val;
5121	return Result;
5122	}
5123
5124	ProcessDeclAttributeOptions WithIgnoreTypeAttributes(bool Val) {
5125	ProcessDeclAttributeOptions Result = *this;
5126	Result.IgnoreTypeAttributes = Val;
5127	return Result;
5128	}
5129
5130	// Should C++11 attributes be processed?
5131	bool IncludeCXX11Attributes;
5132
5133	// Should any type attributes encountered be ignored?
5134	// If this option is false, a diagnostic will be emitted for any type
5135	// attributes of a kind that does not "slide" from the declaration to
5136	// the decl-specifier-seq.
5137	bool IgnoreTypeAttributes;
5138	};
5139
5140	/// ProcessDeclAttributeList - Apply all the decl attributes in the specified
5141	/// attribute list to the specified decl, ignoring any type attributes.
5142	void ProcessDeclAttributeList(Scope S, Decl D,
5143	const ParsedAttributesView &AttrList,
5144	const ProcessDeclAttributeOptions &Options =
5145	ProcessDeclAttributeOptions ());
5146
5147	/// Annotation attributes are the only attributes allowed after an access
5148	/// specifier.
5149	bool ProcessAccessDeclAttributeList(AccessSpecDecl *ASDecl,
5150	const ParsedAttributesView &AttrList);
5151
5152	/// checkUnusedDeclAttributes - Given a declarator which is not being
5153	/// used to build a declaration, complain about any decl attributes
5154	/// which might be lying around on it.
5155	void checkUnusedDeclAttributes(Declarator &D);
5156
5157	void DiagnoseUnknownAttribute(const ParsedAttr &AL);
5158
5159	/// DeclClonePragmaWeak - clone existing decl (maybe definition),
5160	/// \#pragma weak needs a non-definition decl and source may not have one.
5161	NamedDecl DeclClonePragmaWeak(NamedDecl ND, const IdentifierInfo *II,
5162	SourceLocation Loc);
5163
5164	/// DeclApplyPragmaWeak - A declaration (maybe definition) needs \#pragma weak
5165	/// applied to it, possibly with an alias.
5166	void DeclApplyPragmaWeak(Scope S, NamedDecl ND, const WeakInfo &W);
5167
5168	void ProcessPragmaWeak(Scope S, Decl D);
5169	// Decl attributes - this routine is the top level dispatcher.
5170	void ProcessDeclAttributes(Scope S, Decl D, const Declarator &PD);
5171
5172	void PopParsingDeclaration(ParsingDeclState state, Decl *decl);
5173
5174	/// Given a set of delayed diagnostics, re-emit them as if they had
5175	/// been delayed in the current context instead of in the given pool.
5176	/// Essentially, this just moves them to the current pool.
5177	void redelayDiagnostics(sema::DelayedDiagnosticPool &pool);
5178
5179	/// Check that the type is a plain record with one field being a pointer
5180	/// type and the other field being an integer. This matches the common
5181	/// implementation of std::span or sized_allocation_t in P0901R11.
5182	bool CheckSpanLikeType(const AttributeCommonInfo &CI, const QualType &Ty);
5183
5184	/// Check if IdxExpr is a valid parameter index for a function or
5185	/// instance method D. May output an error.
5186	///
5187	/// \returns true if IdxExpr is a valid index.
5188	template <typename AttrInfo>
5189	bool checkFunctionOrMethodParameterIndex(
5190	const Decl D, const* AttrInfo &AI, unsigned AttrArgNum,
5191	const Expr IdxExpr, ParamIdx &Idx, bool* CanIndexImplicitThis = false,
5192	bool CanIndexVariadicArguments = false) {
5193	assert(isFunctionOrMethodOrBlockForAttrSubject(D));
5194
5195	// In C++ the implicit 'this' function parameter also counts.
5196	// Parameters are counted from one.
5197	bool HP = hasFunctionProto(D);
5198	bool HasImplicitThisParam = hasImplicitObjectParameter(D);
5199	bool IV = HP && isFunctionOrMethodVariadic(D);
5200	unsigned NumParams =
5201	(HP ? getFunctionOrMethodNumParams(D) : `0`) + HasImplicitThisParam;
5202
5203	std::optional<llvm::APSInt> IdxInt;
5204	if (IdxExpr->isTypeDependent() \|\|
5205	!(IdxInt = IdxExpr->getIntegerConstantExpr(Ctx: Context))) {
5206	Diag(getAttrLoc(AI), diag::err_attribute_argument_n_type)
5207	<< &AI << AttrArgNum << AANT_ArgumentIntegerConstant
5208	<< IdxExpr->getSourceRange();
5209	return false;
5210	}
5211
5212	unsigned IdxSource = IdxInt ->getLimitedValue(UINT_MAX);
5213	if (IdxSource < `1` \|\|
5214	((!IV \|\| !CanIndexVariadicArguments) && IdxSource > NumParams)) {
5215	Diag(getAttrLoc(AI), diag::err_attribute_argument_out_of_bounds)
5216	<< &AI << AttrArgNum << IdxExpr->getSourceRange();
5217	return false;
5218	}
5219	if (HasImplicitThisParam && !CanIndexImplicitThis) {
5220	if (IdxSource == `1`) {
5221	Diag(getAttrLoc(AI), diag::err_attribute_invalid_implicit_this_argument)
5222	<< &AI << IdxExpr->getSourceRange();
5223	return false;
5224	}
5225	}
5226
5227	Idx = ParamIdx (IdxSource, D);
5228	return true;
5229	}
5230
5231	///@}
5232
5233	//
5234	//
5235	// -------------------------------------------------------------------------
5236	//
5237	//
5238
5239	/// \name C++ Declarations
5240	/// Implementations are in SemaDeclCXX.cpp
5241	///@{
5242
5243	public:
5244	void CheckDelegatingCtorCycles();
5245
5246	/// Called before parsing a function declarator belonging to a function
5247	/// declaration.
5248	void ActOnStartFunctionDeclarationDeclarator(Declarator &D,
5249	unsigned TemplateParameterDepth);
5250
5251	/// Called after parsing a function declarator belonging to a function
5252	/// declaration.
5253	void ActOnFinishFunctionDeclarationDeclarator(Declarator &D);
5254
5255	// Act on C++ namespaces
5256	Decl ActOnStartNamespaceDef(Scope S, SourceLocation InlineLoc,
5257	SourceLocation NamespaceLoc,
5258	SourceLocation IdentLoc, IdentifierInfo *Ident,
5259	SourceLocation LBrace,
5260	const ParsedAttributesView &AttrList,
5261	UsingDirectiveDecl &UsingDecl, bool* IsNested);
5262
5263	/// ActOnFinishNamespaceDef - This callback is called after a namespace is
5264	/// exited. Decl is the DeclTy returned by ActOnStartNamespaceDef.
5265	void ActOnFinishNamespaceDef(Decl *Dcl, SourceLocation RBrace);
5266
5267	NamespaceDecl getStdNamespace() const*;
5268
5269	/// Retrieve the special "std" namespace, which may require us to
5270	/// implicitly define the namespace.
5271	NamespaceDecl *getOrCreateStdNamespace();
5272
5273	CXXRecordDecl getStdBadAlloc() const*;
5274	EnumDecl getStdAlignValT() const*;
5275
5276	TypeAwareAllocationMode ShouldUseTypeAwareOperatorNewOrDelete() const;
5277	FunctionDecl BuildTypeAwareUsualDelete(FunctionTemplateDecl FnDecl,
5278	QualType AllocType, SourceLocation);
5279
5280	ValueDecl tryLookupUnambiguousFieldDecl(RecordDecl ClassDecl,
5281	const IdentifierInfo *MemberOrBase);
5282
5283	enum class ComparisonCategoryUsage {
5284	/// The '<=>' operator was used in an expression and a builtin operator
5285	/// was selected.
5286	OperatorInExpression,
5287	/// A defaulted 'operator<=>' needed the comparison category. This
5288	/// typically only applies to 'std::strong_ordering', due to the implicit
5289	/// fallback return value.
5290	DefaultedOperator,
5291	};
5292
5293	/// Lookup the specified comparison category types in the standard
5294	/// library, an check the VarDecls possibly returned by the operator<=>
5295	/// builtins for that type.
5296	///
5297	/// \return The type of the comparison category type corresponding to the
5298	/// specified Kind, or a null type if an error occurs
5299	QualType CheckComparisonCategoryType(ComparisonCategoryType Kind,
5300	SourceLocation Loc,
5301	ComparisonCategoryUsage Usage);
5302
5303	/// Tests whether Ty is an instance of std::initializer_list and, if
5304	/// it is and Element is not NULL, assigns the element type to Element.
5305	bool isStdInitializerList(QualType Ty, QualType *Element);
5306
5307	/// Tests whether Ty is an instance of std::type_identity and, if
5308	/// it is and TypeArgument is not NULL, assigns the element type to Element.
5309	/// If MalformedDecl is not null, and type_identity was ruled out due to being
5310	/// incorrectly structured despite having the correct name, the faulty Decl
5311	/// will be assigned to MalformedDecl.
5312	bool isStdTypeIdentity(QualType Ty, QualType *TypeArgument,
5313	const Decl MalformedDecl = nullptr**);
5314
5315	/// Looks for the std::initializer_list template and instantiates it
5316	/// with Element, or emits an error if it's not found.
5317	///
5318	/// \returns The instantiated template, or null on error.
5319	QualType BuildStdInitializerList(QualType Element, SourceLocation Loc);
5320
5321	/// Looks for the std::type_identity template and instantiates it
5322	/// with Type, or returns a null type if type_identity has not been declared
5323	///
5324	/// \returns The instantiated template, or null if std::type_identity is not
5325	/// declared
5326	QualType tryBuildStdTypeIdentity(QualType Type, SourceLocation Loc);
5327
5328	/// Determine whether Ctor is an initializer-list constructor, as
5329	/// defined in [dcl.init.list]p2.
5330	bool isInitListConstructor(const FunctionDecl *Ctor);
5331
5332	Decl ActOnUsingDirective(Scope CurScope, SourceLocation UsingLoc,
5333	SourceLocation NamespcLoc, CXXScopeSpec &SS,
5334	SourceLocation IdentLoc,
5335	IdentifierInfo *NamespcName,
5336	const ParsedAttributesView &AttrList);
5337
5338	void PushUsingDirective(Scope S, UsingDirectiveDecl UDir);
5339
5340	Decl ActOnNamespaceAliasDef(Scope CurScope, SourceLocation NamespaceLoc,
5341	SourceLocation AliasLoc, IdentifierInfo *Alias,
5342	CXXScopeSpec &SS, SourceLocation IdentLoc,
5343	IdentifierInfo *Ident);
5344
5345	/// Remove decls we can't actually see from a lookup being used to declare
5346	/// shadow using decls.
5347	///
5348	/// \param S - The scope of the potential shadow decl
5349	/// \param Previous - The lookup of a potential shadow decl's name.
5350	void FilterUsingLookup(Scope *S, LookupResult &lookup);
5351
5352	/// Hides a using shadow declaration. This is required by the current
5353	/// using-decl implementation when a resolvable using declaration in a
5354	/// class is followed by a declaration which would hide or override
5355	/// one or more of the using decl's targets; for example:
5356	///
5357	/// struct Base { void foo(int); };
5358	/// struct Derived : Base {
5359	/// using Base::foo;
5360	/// void foo(int);
5361	/// };
5362	///
5363	/// The governing language is C++03 [namespace.udecl]p12:
5364	///
5365	/// When a using-declaration brings names from a base class into a
5366	/// derived class scope, member functions in the derived class
5367	/// override and/or hide member functions with the same name and
5368	/// parameter types in a base class (rather than conflicting).
5369	///
5370	/// There are two ways to implement this:
5371	/// (1) optimistically create shadow decls when they're not hidden
5372	/// by existing declarations, or
5373	/// (2) don't create any shadow decls (or at least don't make them
5374	/// visible) until we've fully parsed/instantiated the class.
5375	/// The problem with (1) is that we might have to retroactively remove
5376	/// a shadow decl, which requires several O(n) operations because the
5377	/// decl structures are (very reasonably) not designed for removal.
5378	/// (2) avoids this but is very fiddly and phase-dependent.
5379	void HideUsingShadowDecl(Scope S, UsingShadowDecl Shadow);
5380
5381	/// Determines whether to create a using shadow decl for a particular
5382	/// decl, given the set of decls existing prior to this using lookup.
5383	bool CheckUsingShadowDecl(BaseUsingDecl BUD, NamedDecl Target,
5384	const LookupResult &PreviousDecls,
5385	UsingShadowDecl *&PrevShadow);
5386
5387	/// Builds a shadow declaration corresponding to a 'using' declaration.
5388	UsingShadowDecl BuildUsingShadowDecl(Scope S, BaseUsingDecl *BUD,
5389	NamedDecl *Target,
5390	UsingShadowDecl *PrevDecl);
5391
5392	/// Checks that the given using declaration is not an invalid
5393	/// redeclaration. Note that this is checking only for the using decl
5394	/// itself, not for any ill-formedness among the UsingShadowDecls.
5395	bool CheckUsingDeclRedeclaration(SourceLocation UsingLoc,
5396	bool HasTypenameKeyword,
5397	const CXXScopeSpec &SS,
5398	SourceLocation NameLoc,
5399	const LookupResult &Previous);
5400
5401	/// Checks that the given nested-name qualifier used in a using decl
5402	/// in the current context is appropriately related to the current
5403	/// scope. If an error is found, diagnoses it and returns true.
5404	/// R is nullptr, if the caller has not (yet) done a lookup, otherwise it's
5405	/// the result of that lookup. UD is likewise nullptr, except when we have an
5406	/// already-populated UsingDecl whose shadow decls contain the same
5407	/// information (i.e. we're instantiating a UsingDecl with non-dependent
5408	/// scope).
5409	bool CheckUsingDeclQualifier(SourceLocation UsingLoc, bool HasTypename,
5410	const CXXScopeSpec &SS,
5411	const DeclarationNameInfo &NameInfo,
5412	SourceLocation NameLoc,
5413	const LookupResult R = nullptr*,
5414	const UsingDecl UD = nullptr*);
5415
5416	/// Builds a using declaration.
5417	///
5418	/// \param IsInstantiation - Whether this call arises from an
5419	/// instantiation of an unresolved using declaration. We treat
5420	/// the lookup differently for these declarations.
5421	NamedDecl BuildUsingDeclaration(Scope S, AccessSpecifier AS,
5422	SourceLocation UsingLoc,
5423	bool HasTypenameKeyword,
5424	SourceLocation TypenameLoc, CXXScopeSpec &SS,
5425	DeclarationNameInfo NameInfo,
5426	SourceLocation EllipsisLoc,
5427	const ParsedAttributesView &AttrList,
5428	bool IsInstantiation, bool IsUsingIfExists);
5429	NamedDecl BuildUsingEnumDeclaration(Scope S, AccessSpecifier AS,
5430	SourceLocation UsingLoc,
5431	SourceLocation EnumLoc,
5432	SourceLocation NameLoc,
5433	TypeSourceInfo EnumType, EnumDecl ED);
5434	NamedDecl BuildUsingPackDecl(NamedDecl InstantiatedFrom,
5435	ArrayRef<NamedDecl *> Expansions);
5436
5437	/// Additional checks for a using declaration referring to a constructor name.
5438	bool CheckInheritingConstructorUsingDecl(UsingDecl *UD);
5439
5440	/// Given a derived-class using shadow declaration for a constructor and the
5441	/// correspnding base class constructor, find or create the implicit
5442	/// synthesized derived class constructor to use for this initialization.
5443	CXXConstructorDecl *
5444	findInheritingConstructor(SourceLocation Loc, CXXConstructorDecl *BaseCtor,
5445	ConstructorUsingShadowDecl *DerivedShadow);
5446
5447	Decl ActOnUsingDeclaration(Scope CurScope, AccessSpecifier AS,
5448	SourceLocation UsingLoc,
5449	SourceLocation TypenameLoc, CXXScopeSpec &SS,
5450	UnqualifiedId &Name, SourceLocation EllipsisLoc,
5451	const ParsedAttributesView &AttrList);
5452	Decl ActOnUsingEnumDeclaration(Scope CurScope, AccessSpecifier AS,
5453	SourceLocation UsingLoc,
5454	SourceLocation EnumLoc, SourceRange TyLoc,
5455	const IdentifierInfo &II, ParsedType Ty,
5456	const CXXScopeSpec &SS);
5457	Decl ActOnAliasDeclaration(Scope CurScope, AccessSpecifier AS,
5458	MultiTemplateParamsArg TemplateParams,
5459	SourceLocation UsingLoc, UnqualifiedId &Name,
5460	const ParsedAttributesView &AttrList,
5461	TypeResult Type, Decl *DeclFromDeclSpec);
5462
5463	/// BuildCXXConstructExpr - Creates a complete call to a constructor,
5464	/// including handling of its default argument expressions.
5465	///
5466	/// \param ConstructKind - a CXXConstructExpr::ConstructionKind
5467	ExprResult BuildCXXConstructExpr(
5468	SourceLocation ConstructLoc, QualType DeclInitType, NamedDecl *FoundDecl,
5469	CXXConstructorDecl *Constructor, MultiExprArg Exprs,
5470	bool HadMultipleCandidates, bool IsListInitialization,
5471	bool IsStdInitListInitialization, bool RequiresZeroInit,
5472	CXXConstructionKind ConstructKind, SourceRange ParenRange);
5473
5474	/// Build a CXXConstructExpr whose constructor has already been resolved if
5475	/// it denotes an inherited constructor.
5476	ExprResult BuildCXXConstructExpr(
5477	SourceLocation ConstructLoc, QualType DeclInitType,
5478	CXXConstructorDecl Constructor, bool* Elidable, MultiExprArg Exprs,
5479	bool HadMultipleCandidates, bool IsListInitialization,
5480	bool IsStdInitListInitialization, bool RequiresZeroInit,
5481	CXXConstructionKind ConstructKind, SourceRange ParenRange);
5482
5483	// FIXME: Can we remove this and have the above BuildCXXConstructExpr check if
5484	// the constructor can be elidable?
5485	ExprResult BuildCXXConstructExpr(
5486	SourceLocation ConstructLoc, QualType DeclInitType, NamedDecl *FoundDecl,
5487	CXXConstructorDecl Constructor, bool* Elidable, MultiExprArg Exprs,
5488	bool HadMultipleCandidates, bool IsListInitialization,
5489	bool IsStdInitListInitialization, bool RequiresZeroInit,
5490	CXXConstructionKind ConstructKind, SourceRange ParenRange);
5491
5492	ExprResult ConvertMemberDefaultInitExpression(FieldDecl FD, Expr InitExpr,
5493	SourceLocation InitLoc);
5494
5495	/// FinalizeVarWithDestructor - Prepare for calling destructor on the
5496	/// constructed variable.
5497	void FinalizeVarWithDestructor(VarDecl VD, CXXRecordDecl DeclInit);
5498
5499	/// Helper class that collects exception specifications for
5500	/// implicitly-declared special member functions.
5501	class ImplicitExceptionSpecification {
5502	// Pointer to allow copying
5503	Sema *Self;
5504	// We order exception specifications thus:
5505	// noexcept is the most restrictive, but is only used in C++11.
5506	// throw() comes next.
5507	// Then a throw(collected exceptions)
5508	// Finally no specification, which is expressed as noexcept(false).
5509	// throw(...) is used instead if any called function uses it.
5510	ExceptionSpecificationType ComputedEST;
5511	llvm::SmallPtrSet<CanQualType, `4`> ExceptionsSeen;
5512	SmallVector<QualType, `4`> Exceptions;
5513
5514	void ClearExceptions() {
5515	ExceptionsSeen.clear();
5516	Exceptions.clear();
5517	}
5518
5519	public:
5520	explicit ImplicitExceptionSpecification(Sema &Self)
5521	: Self(&Self), ComputedEST(EST_BasicNoexcept) {
5522	if (!Self.getLangOpts().CPlusPlus11)
5523	ComputedEST = EST_DynamicNone;
5524	}
5525
5526	/// Get the computed exception specification type.
5527	ExceptionSpecificationType getExceptionSpecType() const {
5528	assert(!isComputedNoexcept(ComputedEST) &&
5529	"noexcept(expr) should not be a possible result");
5530	return ComputedEST;
5531	}
5532
5533	/// The number of exceptions in the exception specification.
5534	unsigned size() const { return Exceptions.size(); }
5535
5536	/// The set of exceptions in the exception specification.
5537	const QualType data() const* { return Exceptions.data(); }
5538
5539	/// Integrate another called method into the collected data.
5540	void CalledDecl(SourceLocation CallLoc, const CXXMethodDecl *Method);
5541
5542	/// Integrate an invoked expression into the collected data.
5543	void CalledExpr(Expr *E) { CalledStmt(S: E); }
5544
5545	/// Integrate an invoked statement into the collected data.
5546	void CalledStmt(Stmt *S);
5547
5548	/// Overwrite an EPI's exception specification with this
5549	/// computed exception specification.
5550	FunctionProtoType::ExceptionSpecInfo getExceptionSpec() const {
5551	FunctionProtoType::ExceptionSpecInfo ESI;
5552	ESI.Type = getExceptionSpecType();
5553	if (ESI.Type == EST_Dynamic) {
5554	ESI.Exceptions = Exceptions;
5555	} else if (ESI.Type == EST_None) {
5556	/// C++11 [except.spec]p14:
5557	/// The exception-specification is noexcept(false) if the set of
5558	/// potential exceptions of the special member function contains "any"
5559	ESI.Type = EST_NoexceptFalse;
5560	ESI.NoexceptExpr =
5561	Self->ActOnCXXBoolLiteral(OpLoc: SourceLocation (), Kind: tok::kw_false).get();
5562	}
5563	return ESI;
5564	}
5565	};
5566
5567	/// Evaluate the implicit exception specification for a defaulted
5568	/// special member function.
5569	void EvaluateImplicitExceptionSpec(SourceLocation Loc, FunctionDecl *FD);
5570
5571	/// Check the given exception-specification and update the
5572	/// exception specification information with the results.
5573	void checkExceptionSpecification(bool IsTopLevel,
5574	ExceptionSpecificationType EST,
5575	ArrayRef<ParsedType> DynamicExceptions,
5576	ArrayRef<SourceRange> DynamicExceptionRanges,
5577	Expr *NoexceptExpr,
5578	SmallVectorImpl<QualType> &Exceptions,
5579	FunctionProtoType::ExceptionSpecInfo &ESI);
5580
5581	/// Add an exception-specification to the given member or friend function
5582	/// (or function template). The exception-specification was parsed
5583	/// after the function itself was declared.
5584	void actOnDelayedExceptionSpecification(
5585	Decl *D, ExceptionSpecificationType EST, SourceRange SpecificationRange,
5586	ArrayRef<ParsedType> DynamicExceptions,
5587	ArrayRef<SourceRange> DynamicExceptionRanges, Expr *NoexceptExpr);
5588
5589	class InheritedConstructorInfo;
5590
5591	/// Determine if a special member function should have a deleted
5592	/// definition when it is defaulted.
5593	bool ShouldDeleteSpecialMember(CXXMethodDecl *MD, CXXSpecialMemberKind CSM,
5594	InheritedConstructorInfo ICI = nullptr*,
5595	bool Diagnose = false);
5596
5597	/// Produce notes explaining why a defaulted function was defined as deleted.
5598	void DiagnoseDeletedDefaultedFunction(FunctionDecl *FD);
5599
5600	/// Declare the implicit default constructor for the given class.
5601	///
5602	/// \param ClassDecl The class declaration into which the implicit
5603	/// default constructor will be added.
5604	///
5605	/// \returns The implicitly-declared default constructor.
5606	CXXConstructorDecl *
5607	DeclareImplicitDefaultConstructor(CXXRecordDecl *ClassDecl);
5608
5609	/// DefineImplicitDefaultConstructor - Checks for feasibility of
5610	/// defining this constructor as the default constructor.
5611	void DefineImplicitDefaultConstructor(SourceLocation CurrentLocation,
5612	CXXConstructorDecl *Constructor);
5613
5614	/// Declare the implicit destructor for the given class.
5615	///
5616	/// \param ClassDecl The class declaration into which the implicit
5617	/// destructor will be added.
5618	///
5619	/// \returns The implicitly-declared destructor.
5620	CXXDestructorDecl DeclareImplicitDestructor(CXXRecordDecl ClassDecl);
5621
5622	/// DefineImplicitDestructor - Checks for feasibility of
5623	/// defining this destructor as the default destructor.
5624	void DefineImplicitDestructor(SourceLocation CurrentLocation,
5625	CXXDestructorDecl *Destructor);
5626
5627	/// Build an exception spec for destructors that don't have one.
5628	///
5629	/// C++11 says that user-defined destructors with no exception spec get one
5630	/// that looks as if the destructor was implicitly declared.
5631	void AdjustDestructorExceptionSpec(CXXDestructorDecl *Destructor);
5632
5633	/// Define the specified inheriting constructor.
5634	void DefineInheritingConstructor(SourceLocation UseLoc,
5635	CXXConstructorDecl *Constructor);
5636
5637	/// Declare the implicit copy constructor for the given class.
5638	///
5639	/// \param ClassDecl The class declaration into which the implicit
5640	/// copy constructor will be added.
5641	///
5642	/// \returns The implicitly-declared copy constructor.
5643	CXXConstructorDecl DeclareImplicitCopyConstructor(CXXRecordDecl ClassDecl);
5644
5645	/// DefineImplicitCopyConstructor - Checks for feasibility of
5646	/// defining this constructor as the copy constructor.
5647	void DefineImplicitCopyConstructor(SourceLocation CurrentLocation,
5648	CXXConstructorDecl *Constructor);
5649
5650	/// Declare the implicit move constructor for the given class.
5651	///
5652	/// \param ClassDecl The Class declaration into which the implicit
5653	/// move constructor will be added.
5654	///
5655	/// \returns The implicitly-declared move constructor, or NULL if it wasn't
5656	/// declared.
5657	CXXConstructorDecl DeclareImplicitMoveConstructor(CXXRecordDecl ClassDecl);
5658
5659	/// DefineImplicitMoveConstructor - Checks for feasibility of
5660	/// defining this constructor as the move constructor.
5661	void DefineImplicitMoveConstructor(SourceLocation CurrentLocation,
5662	CXXConstructorDecl *Constructor);
5663
5664	/// Declare the implicit copy assignment operator for the given class.
5665	///
5666	/// \param ClassDecl The class declaration into which the implicit
5667	/// copy assignment operator will be added.
5668	///
5669	/// \returns The implicitly-declared copy assignment operator.
5670	CXXMethodDecl DeclareImplicitCopyAssignment(CXXRecordDecl ClassDecl);
5671
5672	/// Defines an implicitly-declared copy assignment operator.
5673	void DefineImplicitCopyAssignment(SourceLocation CurrentLocation,
5674	CXXMethodDecl *MethodDecl);
5675
5676	/// Declare the implicit move assignment operator for the given class.
5677	///
5678	/// \param ClassDecl The Class declaration into which the implicit
5679	/// move assignment operator will be added.
5680	///
5681	/// \returns The implicitly-declared move assignment operator, or NULL if it
5682	/// wasn't declared.
5683	CXXMethodDecl DeclareImplicitMoveAssignment(CXXRecordDecl ClassDecl);
5684
5685	/// Defines an implicitly-declared move assignment operator.
5686	void DefineImplicitMoveAssignment(SourceLocation CurrentLocation,
5687	CXXMethodDecl *MethodDecl);
5688
5689	/// Check a completed declaration of an implicit special member.
5690	void CheckImplicitSpecialMemberDeclaration(Scope S, FunctionDecl FD);
5691
5692	/// Determine whether the given function is an implicitly-deleted
5693	/// special member function.
5694	bool isImplicitlyDeleted(FunctionDecl *FD);
5695
5696	/// Check whether 'this' shows up in the type of a static member
5697	/// function after the (naturally empty) cv-qualifier-seq would be.
5698	///
5699	/// \returns true if an error occurred.
5700	bool checkThisInStaticMemberFunctionType(CXXMethodDecl *Method);
5701
5702	/// Whether this' shows up in the exception specification of a static
5703	/// member function.
5704	bool checkThisInStaticMemberFunctionExceptionSpec(CXXMethodDecl *Method);
5705
5706	/// Check whether 'this' shows up in the attributes of the given
5707	/// static member function.
5708	///
5709	/// \returns true if an error occurred.
5710	bool checkThisInStaticMemberFunctionAttributes(CXXMethodDecl *Method);
5711
5712	bool CheckImmediateEscalatingFunctionDefinition(
5713	FunctionDecl FD, const* sema::FunctionScopeInfo *FSI);
5714
5715	void DiagnoseImmediateEscalatingReason(FunctionDecl *FD);
5716
5717	/// Given a constructor and the set of arguments provided for the
5718	/// constructor, convert the arguments and add any required default arguments
5719	/// to form a proper call to this constructor.
5720	///
5721	/// \returns true if an error occurred, false otherwise.
5722	bool CompleteConstructorCall(CXXConstructorDecl *Constructor,
5723	QualType DeclInitType, MultiExprArg ArgsPtr,
5724	SourceLocation Loc,
5725	SmallVectorImpl<Expr *> &ConvertedArgs,
5726	bool AllowExplicit = false,
5727	bool IsListInitialization = false);
5728
5729	/// ActOnCXXEnterDeclInitializer - Invoked when we are about to parse an
5730	/// initializer for the declaration 'Dcl'.
5731	/// After this method is called, according to [C++ 3.4.1p13], if 'Dcl' is a
5732	/// static data member of class X, names should be looked up in the scope of
5733	/// class X.
5734	void ActOnCXXEnterDeclInitializer(Scope S, Decl Dcl);
5735
5736	/// ActOnCXXExitDeclInitializer - Invoked after we are finished parsing an
5737	/// initializer for the declaration 'Dcl'.
5738	void ActOnCXXExitDeclInitializer(Scope S, Decl Dcl);
5739
5740	/// Define the "body" of the conversion from a lambda object to a
5741	/// function pointer.
5742	///
5743	/// This routine doesn't actually define a sensible body; rather, it fills
5744	/// in the initialization expression needed to copy the lambda object into
5745	/// the block, and IR generation actually generates the real body of the
5746	/// block pointer conversion.
5747	void
5748	DefineImplicitLambdaToFunctionPointerConversion(SourceLocation CurrentLoc,
5749	CXXConversionDecl *Conv);
5750
5751	/// Define the "body" of the conversion from a lambda object to a
5752	/// block pointer.
5753	///
5754	/// This routine doesn't actually define a sensible body; rather, it fills
5755	/// in the initialization expression needed to copy the lambda object into
5756	/// the block, and IR generation actually generates the real body of the
5757	/// block pointer conversion.
5758	void DefineImplicitLambdaToBlockPointerConversion(SourceLocation CurrentLoc,
5759	CXXConversionDecl *Conv);
5760
5761	/// ActOnStartLinkageSpecification - Parsed the beginning of a C++
5762	/// linkage specification, including the language and (if present)
5763	/// the '{'. ExternLoc is the location of the 'extern', Lang is the
5764	/// language string literal. LBraceLoc, if valid, provides the location of
5765	/// the '{' brace. Otherwise, this linkage specification does not
5766	/// have any braces.
5767	Decl ActOnStartLinkageSpecification(Scope S, SourceLocation ExternLoc,
5768	Expr *LangStr, SourceLocation LBraceLoc);
5769
5770	/// ActOnFinishLinkageSpecification - Complete the definition of
5771	/// the C++ linkage specification LinkageSpec. If RBraceLoc is
5772	/// valid, it's the position of the closing '}' brace in a linkage
5773	/// specification that uses braces.
5774	Decl ActOnFinishLinkageSpecification(Scope S, Decl *LinkageSpec,
5775	SourceLocation RBraceLoc);
5776
5777	//===--------------------------------------------------------------------===//
5778	// C++ Classes
5779	//
5780
5781	/// Get the class that is directly named by the current context. This is the
5782	/// class for which an unqualified-id in this scope could name a constructor
5783	/// or destructor.
5784	///
5785	/// If the scope specifier denotes a class, this will be that class.
5786	/// If the scope specifier is empty, this will be the class whose
5787	/// member-specification we are currently within. Otherwise, there
5788	/// is no such class.
5789	CXXRecordDecl getCurrentClass(Scope S, const CXXScopeSpec *SS);
5790
5791	/// isCurrentClassName - Determine whether the identifier II is the
5792	/// name of the class type currently being defined. In the case of
5793	/// nested classes, this will only return true if II is the name of
5794	/// the innermost class.
5795	bool isCurrentClassName(const IdentifierInfo &II, Scope *S,
5796	const CXXScopeSpec SS = nullptr*);
5797
5798	/// Determine whether the identifier II is a typo for the name of
5799	/// the class type currently being defined. If so, update it to the identifier
5800	/// that should have been used.
5801	bool isCurrentClassNameTypo(IdentifierInfo &II, const* CXXScopeSpec *SS);
5802
5803	/// ActOnAccessSpecifier - Parsed an access specifier followed by a colon.
5804	bool ActOnAccessSpecifier(AccessSpecifier Access, SourceLocation ASLoc,
5805	SourceLocation ColonLoc,
5806	const ParsedAttributesView &Attrs);
5807
5808	/// ActOnCXXMemberDeclarator - This is invoked when a C++ class member
5809	/// declarator is parsed. 'AS' is the access specifier, 'BW' specifies the
5810	/// bitfield width if there is one, 'InitExpr' specifies the initializer if
5811	/// one has been parsed, and 'InitStyle' is set if an in-class initializer is
5812	/// present (but parsing it has been deferred).
5813	NamedDecl *
5814	ActOnCXXMemberDeclarator(Scope *S, AccessSpecifier AS, Declarator &D,
5815	MultiTemplateParamsArg TemplateParameterLists,
5816	Expr BitfieldWidth, const* VirtSpecifiers &VS,
5817	InClassInitStyle InitStyle);
5818
5819	/// Enter a new C++ default initializer scope. After calling this, the
5820	/// caller must call \ref ActOnFinishCXXInClassMemberInitializer, even if
5821	/// parsing or instantiating the initializer failed.
5822	void ActOnStartCXXInClassMemberInitializer();
5823
5824	/// This is invoked after parsing an in-class initializer for a
5825	/// non-static C++ class member, and after instantiating an in-class
5826	/// initializer in a class template. Such actions are deferred until the class
5827	/// is complete.
5828	void ActOnFinishCXXInClassMemberInitializer(Decl *VarDecl,
5829	SourceLocation EqualLoc,
5830	ExprResult Init);
5831
5832	/// Handle a C++ member initializer using parentheses syntax.
5833	MemInitResult
5834	ActOnMemInitializer(Decl ConstructorD, Scope S, CXXScopeSpec &SS,
5835	IdentifierInfo *MemberOrBase, ParsedType TemplateTypeTy,
5836	const DeclSpec &DS, SourceLocation IdLoc,
5837	SourceLocation LParenLoc, ArrayRef<Expr *> Args,
5838	SourceLocation RParenLoc, SourceLocation EllipsisLoc);
5839
5840	/// Handle a C++ member initializer using braced-init-list syntax.
5841	MemInitResult ActOnMemInitializer(Decl ConstructorD, Scope S,
5842	CXXScopeSpec &SS,
5843	IdentifierInfo *MemberOrBase,
5844	ParsedType TemplateTypeTy,
5845	const DeclSpec &DS, SourceLocation IdLoc,
5846	Expr *InitList, SourceLocation EllipsisLoc);
5847
5848	/// Handle a C++ member initializer.
5849	MemInitResult BuildMemInitializer(Decl ConstructorD, Scope S,
5850	CXXScopeSpec &SS,
5851	IdentifierInfo *MemberOrBase,
5852	ParsedType TemplateTypeTy,
5853	const DeclSpec &DS, SourceLocation IdLoc,
5854	Expr *Init, SourceLocation EllipsisLoc);
5855
5856	MemInitResult BuildMemberInitializer(ValueDecl Member, Expr Init,
5857	SourceLocation IdLoc);
5858
5859	MemInitResult BuildBaseInitializer(QualType BaseType,
5860	TypeSourceInfo BaseTInfo, Expr Init,
5861	CXXRecordDecl *ClassDecl,
5862	SourceLocation EllipsisLoc);
5863
5864	MemInitResult BuildDelegatingInitializer(TypeSourceInfo TInfo, Expr Init,
5865	CXXRecordDecl *ClassDecl);
5866
5867	bool SetDelegatingInitializer(CXXConstructorDecl *Constructor,
5868	CXXCtorInitializer *Initializer);
5869
5870	bool SetCtorInitializers(CXXConstructorDecl Constructor, bool* AnyErrors,
5871	ArrayRef<CXXCtorInitializer *> Initializers = {});
5872
5873	/// MarkBaseAndMemberDestructorsReferenced - Given a record decl,
5874	/// mark all the non-trivial destructors of its members and bases as
5875	/// referenced.
5876	void MarkBaseAndMemberDestructorsReferenced(SourceLocation Loc,
5877	CXXRecordDecl *Record);
5878
5879	/// Mark destructors of virtual bases of this class referenced. In the Itanium
5880	/// C++ ABI, this is done when emitting a destructor for any non-abstract
5881	/// class. In the Microsoft C++ ABI, this is done any time a class's
5882	/// destructor is referenced.
5883	void MarkVirtualBaseDestructorsReferenced(
5884	SourceLocation Location, CXXRecordDecl *ClassDecl,
5885	llvm::SmallPtrSetImpl<const CXXRecordDecl > DirectVirtualBases =
5886	nullptr);
5887
5888	/// Do semantic checks to allow the complete destructor variant to be emitted
5889	/// when the destructor is defined in another translation unit. In the Itanium
5890	/// C++ ABI, destructor variants are emitted together. In the MS C++ ABI, they
5891	/// can be emitted in separate TUs. To emit the complete variant, run a subset
5892	/// of the checks performed when emitting a regular destructor.
5893	void CheckCompleteDestructorVariant(SourceLocation CurrentLocation,
5894	CXXDestructorDecl *Dtor);
5895
5896	/// The list of classes whose vtables have been used within
5897	/// this translation unit, and the source locations at which the
5898	/// first use occurred.
5899	typedef std::pair<CXXRecordDecl *, SourceLocation> VTableUse;
5900
5901	/// The list of vtables that are required but have not yet been
5902	/// materialized.
5903	SmallVector<VTableUse, `16`> VTableUses;
5904
5905	/// The set of classes whose vtables have been used within
5906	/// this translation unit, and a bit that will be true if the vtable is
5907	/// required to be emitted (otherwise, it should be emitted only if needed
5908	/// by code generation).
5909	llvm::DenseMap<CXXRecordDecl , bool*> VTablesUsed;
5910
5911	/// Load any externally-stored vtable uses.
5912	void LoadExternalVTableUses();
5913
5914	/// Note that the vtable for the given class was used at the
5915	/// given location.
5916	void MarkVTableUsed(SourceLocation Loc, CXXRecordDecl *Class,
5917	bool DefinitionRequired = false);
5918
5919	/// Mark the exception specifications of all virtual member functions
5920	/// in the given class as needed.
5921	void MarkVirtualMemberExceptionSpecsNeeded(SourceLocation Loc,
5922	const CXXRecordDecl *RD);
5923
5924	/// MarkVirtualMembersReferenced - Will mark all members of the given
5925	/// CXXRecordDecl referenced.
5926	void MarkVirtualMembersReferenced(SourceLocation Loc, const CXXRecordDecl *RD,
5927	bool ConstexprOnly = false);
5928
5929	/// Define all of the vtables that have been used in this
5930	/// translation unit and reference any virtual members used by those
5931	/// vtables.
5932	///
5933	/// \returns true if any work was done, false otherwise.
5934	bool DefineUsedVTables();
5935
5936	/// AddImplicitlyDeclaredMembersToClass - Adds any implicitly-declared
5937	/// special functions, such as the default constructor, copy
5938	/// constructor, or destructor, to the given C++ class (C++
5939	/// [special]p1). This routine can only be executed just before the
5940	/// definition of the class is complete.
5941	void AddImplicitlyDeclaredMembersToClass(CXXRecordDecl *ClassDecl);
5942
5943	/// ActOnMemInitializers - Handle the member initializers for a constructor.
5944	void ActOnMemInitializers(Decl *ConstructorDecl, SourceLocation ColonLoc,
5945	ArrayRef<CXXCtorInitializer *> MemInits,
5946	bool AnyErrors);
5947
5948	/// Check class-level dllimport/dllexport attribute. The caller must
5949	/// ensure that referenceDLLExportedClassMethods is called some point later
5950	/// when all outer classes of Class are complete.
5951	void checkClassLevelDLLAttribute(CXXRecordDecl *Class);
5952	void checkClassLevelCodeSegAttribute(CXXRecordDecl *Class);
5953
5954	void referenceDLLExportedClassMethods();
5955
5956	/// Perform propagation of DLL attributes from a derived class to a
5957	/// templated base class for MS compatibility.
5958	void propagateDLLAttrToBaseClassTemplate(
5959	CXXRecordDecl Class, Attr ClassAttr,
5960	ClassTemplateSpecializationDecl *BaseTemplateSpec,
5961	SourceLocation BaseLoc);
5962
5963	/// Perform semantic checks on a class definition that has been
5964	/// completing, introducing implicitly-declared members, checking for
5965	/// abstract types, etc.
5966	///
5967	/// \param S The scope in which the class was parsed. Null if we didn't just
5968	/// parse a class definition.
5969	/// \param Record The completed class.
5970	void CheckCompletedCXXClass(Scope S, CXXRecordDecl Record);
5971
5972	/// Check that the C++ class annoated with "trivial_abi" satisfies all the
5973	/// conditions that are needed for the attribute to have an effect.
5974	void checkIllFormedTrivialABIStruct(CXXRecordDecl &RD);
5975
5976	/// Check that VTable Pointer authentication is only being set on the first
5977	/// first instantiation of the vtable
5978	void checkIncorrectVTablePointerAuthenticationAttribute(CXXRecordDecl &RD);
5979
5980	void ActOnFinishCXXMemberSpecification(Scope *S, SourceLocation RLoc,
5981	Decl *TagDecl, SourceLocation LBrac,
5982	SourceLocation RBrac,
5983	const ParsedAttributesView &AttrList);
5984
5985	/// Perform any semantic analysis which needs to be delayed until all
5986	/// pending class member declarations have been parsed.
5987	void ActOnFinishCXXMemberDecls();
5988	void ActOnFinishCXXNonNestedClass();
5989
5990	/// This is used to implement the constant expression evaluation part of the
5991	/// attribute enable_if extension. There is nothing in standard C++ which
5992	/// would require reentering parameters.
5993	void ActOnReenterCXXMethodParameter(Scope S, ParmVarDecl Param);
5994	unsigned ActOnReenterTemplateScope(Decl *Template,
5995	llvm::function_ref<Scope *()> EnterScope);
5996	void ActOnStartDelayedMemberDeclarations(Scope S, Decl Record);
5997
5998	/// ActOnStartDelayedCXXMethodDeclaration - We have completed
5999	/// parsing a top-level (non-nested) C++ class, and we are now
6000	/// parsing those parts of the given Method declaration that could
6001	/// not be parsed earlier (C++ [class.mem]p2), such as default
6002	/// arguments. This action should enter the scope of the given
6003	/// Method declaration as if we had just parsed the qualified method
6004	/// name. However, it should not bring the parameters into scope;
6005	/// that will be performed by ActOnDelayedCXXMethodParameter.
6006	void ActOnStartDelayedCXXMethodDeclaration(Scope S, Decl Method);
6007	void ActOnDelayedCXXMethodParameter(Scope S, Decl Param);
6008	void ActOnFinishDelayedMemberDeclarations(Scope S, Decl Record);
6009
6010	/// ActOnFinishDelayedCXXMethodDeclaration - We have finished
6011	/// processing the delayed method declaration for Method. The method
6012	/// declaration is now considered finished. There may be a separate
6013	/// ActOnStartOfFunctionDef action later (not necessarily
6014	/// immediately!) for this method, if it was also defined inside the
6015	/// class body.
6016	void ActOnFinishDelayedCXXMethodDeclaration(Scope S, Decl Method);
6017	void ActOnFinishDelayedMemberInitializers(Decl *Record);
6018
6019	enum class StringEvaluationContext { StaticAssert = `0`, Asm = `1` };
6020
6021	bool EvaluateAsString(Expr *Message, APValue &Result, ASTContext &Ctx,
6022	StringEvaluationContext EvalContext,
6023	bool ErrorOnInvalidMessage);
6024	bool EvaluateAsString(Expr *Message, std::string &Result, ASTContext &Ctx,
6025	StringEvaluationContext EvalContext,
6026	bool ErrorOnInvalidMessage);
6027
6028	Decl *ActOnStaticAssertDeclaration(SourceLocation StaticAssertLoc,
6029	Expr AssertExpr, Expr AssertMessageExpr,
6030	SourceLocation RParenLoc);
6031	Decl *BuildStaticAssertDeclaration(SourceLocation StaticAssertLoc,
6032	Expr AssertExpr, Expr AssertMessageExpr,
6033	SourceLocation RParenLoc, bool Failed);
6034
6035	/// Try to print more useful information about a failed static_assert
6036	/// with expression \E
6037	void DiagnoseStaticAssertDetails(const Expr *E);
6038
6039	/// If E represents a built-in type trait, or a known standard type trait,
6040	/// try to print more information about why the type type-trait failed.
6041	/// This assumes we already evaluated the expression to a false boolean value.
6042	void DiagnoseTypeTraitDetails(const Expr *E);
6043
6044	/// Handle a friend type declaration. This works in tandem with
6045	/// ActOnTag.
6046	///
6047	/// Notes on friend class templates:
6048	///
6049	/// We generally treat friend class declarations as if they were
6050	/// declaring a class. So, for example, the elaborated type specifier
6051	/// in a friend declaration is required to obey the restrictions of a
6052	/// class-head (i.e. no typedefs in the scope chain), template
6053	/// parameters are required to match up with simple template-ids, &c.
6054	/// However, unlike when declaring a template specialization, it's
6055	/// okay to refer to a template specialization without an empty
6056	/// template parameter declaration, e.g.
6057	/// friend class A<T>::B<unsigned>;
6058	/// We permit this as a special case; if there are any template
6059	/// parameters present at all, require proper matching, i.e.
6060	/// template <> template \<class T> friend class A<int>::B;
6061	Decl ActOnFriendTypeDecl(Scope S, const DeclSpec &DS,
6062	MultiTemplateParamsArg TemplateParams,
6063	SourceLocation EllipsisLoc);
6064	NamedDecl ActOnFriendFunctionDecl(Scope S, Declarator &D,
6065	MultiTemplateParamsArg TemplateParams);
6066
6067	/// CheckConstructorDeclarator - Called by ActOnDeclarator to check
6068	/// the well-formedness of the constructor declarator @p D with type @p
6069	/// R. If there are any errors in the declarator, this routine will
6070	/// emit diagnostics and set the invalid bit to true. In any case, the type
6071	/// will be updated to reflect a well-formed type for the constructor and
6072	/// returned.
6073	QualType CheckConstructorDeclarator(Declarator &D, QualType R,
6074	StorageClass &SC);
6075
6076	/// CheckConstructor - Checks a fully-formed constructor for
6077	/// well-formedness, issuing any diagnostics required. Returns true if
6078	/// the constructor declarator is invalid.
6079	void CheckConstructor(CXXConstructorDecl *Constructor);
6080
6081	/// CheckDestructorDeclarator - Called by ActOnDeclarator to check
6082	/// the well-formednes of the destructor declarator @p D with type @p
6083	/// R. If there are any errors in the declarator, this routine will
6084	/// emit diagnostics and set the declarator to invalid. Even if this happens,
6085	/// will be updated to reflect a well-formed type for the destructor and
6086	/// returned.
6087	QualType CheckDestructorDeclarator(Declarator &D, QualType R,
6088	StorageClass &SC);
6089
6090	/// CheckDestructor - Checks a fully-formed destructor definition for
6091	/// well-formedness, issuing any diagnostics required. Returns true
6092	/// on error.
6093	bool CheckDestructor(CXXDestructorDecl *Destructor);
6094
6095	/// CheckConversionDeclarator - Called by ActOnDeclarator to check the
6096	/// well-formednes of the conversion function declarator @p D with
6097	/// type @p R. If there are any errors in the declarator, this routine
6098	/// will emit diagnostics and return true. Otherwise, it will return
6099	/// false. Either way, the type @p R will be updated to reflect a
6100	/// well-formed type for the conversion operator.
6101	void CheckConversionDeclarator(Declarator &D, QualType &R, StorageClass &SC);
6102
6103	/// ActOnConversionDeclarator - Called by ActOnDeclarator to complete
6104	/// the declaration of the given C++ conversion function. This routine
6105	/// is responsible for recording the conversion function in the C++
6106	/// class, if possible.
6107	Decl ActOnConversionDeclarator(CXXConversionDecl Conversion);
6108
6109	/// Check the validity of a declarator that we parsed for a deduction-guide.
6110	/// These aren't actually declarators in the grammar, so we need to check that
6111	/// the user didn't specify any pieces that are not part of the
6112	/// deduction-guide grammar. Return true on invalid deduction-guide.
6113	bool CheckDeductionGuideDeclarator(Declarator &D, QualType &R,
6114	StorageClass &SC);
6115
6116	void CheckExplicitlyDefaultedFunction(Scope S, FunctionDecl MD);
6117
6118	bool CheckExplicitlyDefaultedSpecialMember(CXXMethodDecl *MD,
6119	CXXSpecialMemberKind CSM,
6120	SourceLocation DefaultLoc);
6121	void CheckDelayedMemberExceptionSpecs();
6122
6123	/// Kinds of defaulted comparison operator functions.
6124	enum class DefaultedComparisonKind : unsigned char {
6125	/// This is not a defaultable comparison operator.
6126	None,
6127	/// This is an operator== that should be implemented as a series of
6128	/// subobject comparisons.
6129	Equal,
6130	/// This is an operator<=> that should be implemented as a series of
6131	/// subobject comparisons.
6132	ThreeWay,
6133	/// This is an operator!= that should be implemented as a rewrite in terms
6134	/// of a == comparison.
6135	NotEqual,
6136	/// This is an <, <=, >, or >= that should be implemented as a rewrite in
6137	/// terms of a <=> comparison.
6138	Relational,
6139	};
6140
6141	bool CheckExplicitlyDefaultedComparison(Scope S, FunctionDecl MD,
6142	DefaultedComparisonKind DCK);
6143	void DeclareImplicitEqualityComparison(CXXRecordDecl *RD,
6144	FunctionDecl *Spaceship);
6145	void DefineDefaultedComparison(SourceLocation Loc, FunctionDecl *FD,
6146	DefaultedComparisonKind DCK);
6147
6148	void CheckExplicitObjectMemberFunction(Declarator &D, DeclarationName Name,
6149	QualType R, bool IsLambda,
6150	DeclContext DC = nullptr*);
6151	void CheckExplicitObjectMemberFunction(DeclContext *DC, Declarator &D,
6152	DeclarationName Name, QualType R);
6153	void CheckExplicitObjectLambda(Declarator &D);
6154
6155	//===--------------------------------------------------------------------===//
6156	// C++ Derived Classes
6157	//
6158
6159	/// Check the validity of a C++ base class specifier.
6160	///
6161	/// \returns a new CXXBaseSpecifier if well-formed, emits diagnostics
6162	/// and returns NULL otherwise.
6163	CXXBaseSpecifier CheckBaseSpecifier(CXXRecordDecl Class,
6164	SourceRange SpecifierRange, bool Virtual,
6165	AccessSpecifier Access,
6166	TypeSourceInfo *TInfo,
6167	SourceLocation EllipsisLoc);
6168
6169	/// ActOnBaseSpecifier - Parsed a base specifier. A base specifier is
6170	/// one entry in the base class list of a class specifier, for
6171	/// example:
6172	/// class foo : public bar, virtual private baz {
6173	/// 'public bar' and 'virtual private baz' are each base-specifiers.
6174	BaseResult ActOnBaseSpecifier(Decl *classdecl, SourceRange SpecifierRange,
6175	const ParsedAttributesView &Attrs, bool Virtual,
6176	AccessSpecifier Access, ParsedType basetype,
6177	SourceLocation BaseLoc,
6178	SourceLocation EllipsisLoc);
6179
6180	/// Performs the actual work of attaching the given base class
6181	/// specifiers to a C++ class.
6182	bool AttachBaseSpecifiers(CXXRecordDecl *Class,
6183	MutableArrayRef<CXXBaseSpecifier *> Bases);
6184
6185	/// ActOnBaseSpecifiers - Attach the given base specifiers to the
6186	/// class, after checking whether there are any duplicate base
6187	/// classes.
6188	void ActOnBaseSpecifiers(Decl *ClassDecl,
6189	MutableArrayRef<CXXBaseSpecifier *> Bases);
6190
6191	/// Determine whether the type \p Derived is a C++ class that is
6192	/// derived from the type \p Base.
6193	bool IsDerivedFrom(SourceLocation Loc, CXXRecordDecl *Derived,
6194	CXXRecordDecl *Base, CXXBasePaths &Paths);
6195	bool IsDerivedFrom(SourceLocation Loc, CXXRecordDecl *Derived,
6196	CXXRecordDecl *Base);
6197	bool IsDerivedFrom(SourceLocation Loc, QualType Derived, QualType Base);
6198	bool IsDerivedFrom(SourceLocation Loc, QualType Derived, QualType Base,
6199	CXXBasePaths &Paths);
6200
6201	// FIXME: I don't like this name.
6202	void BuildBasePathArray(const CXXBasePaths &Paths, CXXCastPath &BasePath);
6203
6204	bool CheckDerivedToBaseConversion(QualType Derived, QualType Base,
6205	SourceLocation Loc, SourceRange Range,
6206	CXXCastPath BasePath = nullptr*,
6207	bool IgnoreAccess = false);
6208
6209	/// CheckDerivedToBaseConversion - Check whether the Derived-to-Base
6210	/// conversion (where Derived and Base are class types) is
6211	/// well-formed, meaning that the conversion is unambiguous (and
6212	/// that all of the base classes are accessible). Returns true
6213	/// and emits a diagnostic if the code is ill-formed, returns false
6214	/// otherwise. Loc is the location where this routine should point to
6215	/// if there is an error, and Range is the source range to highlight
6216	/// if there is an error.
6217	///
6218	/// If either InaccessibleBaseID or AmbiguousBaseConvID are 0, then the
6219	/// diagnostic for the respective type of error will be suppressed, but the
6220	/// check for ill-formed code will still be performed.
6221	bool CheckDerivedToBaseConversion(QualType Derived, QualType Base,
6222	unsigned InaccessibleBaseID,
6223	unsigned AmbiguousBaseConvID,
6224	SourceLocation Loc, SourceRange Range,
6225	DeclarationName Name, CXXCastPath *BasePath,
6226	bool IgnoreAccess = false);
6227
6228	/// Builds a string representing ambiguous paths from a
6229	/// specific derived class to different subobjects of the same base
6230	/// class.
6231	///
6232	/// This function builds a string that can be used in error messages
6233	/// to show the different paths that one can take through the
6234	/// inheritance hierarchy to go from the derived class to different
6235	/// subobjects of a base class. The result looks something like this:
6236	/// @code
6237	/// struct D -> struct B -> struct A
6238	/// struct D -> struct C -> struct A
6239	/// @endcode
6240	std::string getAmbiguousPathsDisplayString(CXXBasePaths &Paths);
6241
6242	bool CheckOverridingFunctionAttributes(CXXMethodDecl *New,
6243	const CXXMethodDecl *Old);
6244
6245	/// CheckOverridingFunctionReturnType - Checks whether the return types are
6246	/// covariant, according to C++ [class.virtual]p5.
6247	bool CheckOverridingFunctionReturnType(const CXXMethodDecl *New,
6248	const CXXMethodDecl *Old);
6249
6250	// Check that the overriding method has no explicit object parameter.
6251	bool CheckExplicitObjectOverride(CXXMethodDecl *New,
6252	const CXXMethodDecl *Old);
6253
6254	/// Mark the given method pure.
6255	///
6256	/// \param Method the method to be marked pure.
6257	///
6258	/// \param InitRange the source range that covers the "0" initializer.
6259	bool CheckPureMethod(CXXMethodDecl *Method, SourceRange InitRange);
6260
6261	/// CheckOverrideControl - Check C++11 override control semantics.
6262	void CheckOverrideControl(NamedDecl *D);
6263
6264	/// DiagnoseAbsenceOfOverrideControl - Diagnose if 'override' keyword was
6265	/// not used in the declaration of an overriding method.
6266	void DiagnoseAbsenceOfOverrideControl(NamedDecl D, bool* Inconsistent);
6267
6268	/// CheckIfOverriddenFunctionIsMarkedFinal - Checks whether a virtual member
6269	/// function overrides a virtual member function marked 'final', according to
6270	/// C++11 [class.virtual]p4.
6271	bool CheckIfOverriddenFunctionIsMarkedFinal(const CXXMethodDecl *New,
6272	const CXXMethodDecl *Old);
6273
6274	enum AbstractDiagSelID {
6275	AbstractNone = -`1`,
6276	AbstractReturnType,
6277	AbstractParamType,
6278	AbstractVariableType,
6279	AbstractFieldType,
6280	AbstractIvarType,
6281	AbstractSynthesizedIvarType,
6282	AbstractArrayType
6283	};
6284
6285	struct TypeDiagnoser;
6286
6287	bool isAbstractType(SourceLocation Loc, QualType T);
6288	bool RequireNonAbstractType(SourceLocation Loc, QualType T,
6289	TypeDiagnoser &Diagnoser);
6290	template <typename... Ts>
6291	bool RequireNonAbstractType(SourceLocation Loc, QualType T, unsigned DiagID,
6292	const Ts &...Args) {
6293	BoundTypeDiagnoser<Ts...> Diagnoser(DiagID, Args...);
6294	return RequireNonAbstractType(Loc, T, Diagnoser);
6295	}
6296
6297	void DiagnoseAbstractType(const CXXRecordDecl *RD);
6298
6299	//===--------------------------------------------------------------------===//
6300	// C++ Overloaded Operators [C++ 13.5]
6301	//
6302
6303	/// CheckOverloadedOperatorDeclaration - Check whether the declaration
6304	/// of this overloaded operator is well-formed. If so, returns false;
6305	/// otherwise, emits appropriate diagnostics and returns true.
6306	bool CheckOverloadedOperatorDeclaration(FunctionDecl *FnDecl);
6307
6308	/// CheckLiteralOperatorDeclaration - Check whether the declaration
6309	/// of this literal operator function is well-formed. If so, returns
6310	/// false; otherwise, emits appropriate diagnostics and returns true.
6311	bool CheckLiteralOperatorDeclaration(FunctionDecl *FnDecl);
6312
6313	/// ActOnExplicitBoolSpecifier - Build an ExplicitSpecifier from an expression
6314	/// found in an explicit(bool) specifier.
6315	ExplicitSpecifier ActOnExplicitBoolSpecifier(Expr *E);
6316
6317	/// tryResolveExplicitSpecifier - Attempt to resolve the explict specifier.
6318	/// Returns true if the explicit specifier is now resolved.
6319	bool tryResolveExplicitSpecifier(ExplicitSpecifier &ExplicitSpec);
6320
6321	/// ActOnCXXConditionDeclarationExpr - Parsed a condition declaration of a
6322	/// C++ if/switch/while/for statement.
6323	/// e.g: "if (int x = f()) {...}"
6324	DeclResult ActOnCXXConditionDeclaration(Scope *S, Declarator &D);
6325
6326	// Emitting members of dllexported classes is delayed until the class
6327	// (including field initializers) is fully parsed.
6328	SmallVector<CXXRecordDecl *, `4`> DelayedDllExportClasses;
6329	SmallVector<CXXMethodDecl *, `4`> DelayedDllExportMemberFunctions;
6330
6331	/// Merge the exception specifications of two variable declarations.
6332	///
6333	/// This is called when there's a redeclaration of a VarDecl. The function
6334	/// checks if the redeclaration might have an exception specification and
6335	/// validates compatibility and merges the specs if necessary.
6336	void MergeVarDeclExceptionSpecs(VarDecl New, VarDecl Old);
6337
6338	/// MergeCXXFunctionDecl - Merge two declarations of the same C++
6339	/// function, once we already know that they have the same
6340	/// type. Subroutine of MergeFunctionDecl. Returns true if there was an
6341	/// error, false otherwise.
6342	bool MergeCXXFunctionDecl(FunctionDecl New, FunctionDecl Old, Scope *S);
6343
6344	/// Helpers for dealing with blocks and functions.
6345	void CheckCXXDefaultArguments(FunctionDecl *FD);
6346
6347	/// CheckExtraCXXDefaultArguments - Check for any extra default
6348	/// arguments in the declarator, which is not a function declaration
6349	/// or definition and therefore is not permitted to have default
6350	/// arguments. This routine should be invoked for every declarator
6351	/// that is not a function declaration or definition.
6352	void CheckExtraCXXDefaultArguments(Declarator &D);
6353
6354	CXXSpecialMemberKind getSpecialMember(const CXXMethodDecl *MD) {
6355	return getDefaultedFunctionKind(FD: MD).asSpecialMember();
6356	}
6357
6358	/// Perform semantic analysis for the variable declaration that
6359	/// occurs within a C++ catch clause, returning the newly-created
6360	/// variable.
6361	VarDecl BuildExceptionDeclaration(Scope S, TypeSourceInfo *TInfo,
6362	SourceLocation StartLoc,
6363	SourceLocation IdLoc,
6364	const IdentifierInfo *Id);
6365
6366	/// ActOnExceptionDeclarator - Parsed the exception-declarator in a C++ catch
6367	/// handler.
6368	Decl ActOnExceptionDeclarator(Scope S, Declarator &D);
6369
6370	void DiagnoseReturnInConstructorExceptionHandler(CXXTryStmt *TryBlock);
6371
6372	/// Handle a friend tag declaration where the scope specifier was
6373	/// templated.
6374	DeclResult ActOnTemplatedFriendTag(Scope *S, SourceLocation FriendLoc,
6375	unsigned TagSpec, SourceLocation TagLoc,
6376	CXXScopeSpec &SS, IdentifierInfo *Name,
6377	SourceLocation NameLoc,
6378	SourceLocation EllipsisLoc,
6379	const ParsedAttributesView &Attr,
6380	MultiTemplateParamsArg TempParamLists);
6381
6382	MSPropertyDecl HandleMSProperty(Scope S, RecordDecl *TagD,
6383	SourceLocation DeclStart, Declarator &D,
6384	Expr *BitfieldWidth,
6385	InClassInitStyle InitStyle,
6386	AccessSpecifier AS,
6387	const ParsedAttr &MSPropertyAttr);
6388
6389	/// Diagnose why the specified class does not have a trivial special member of
6390	/// the given kind.
6391	void DiagnoseNontrivial(const CXXRecordDecl *Record,
6392	CXXSpecialMemberKind CSM);
6393
6394	/// Determine whether a defaulted or deleted special member function is
6395	/// trivial, as specified in C++11 [class.ctor]p5, C++11 [class.copy]p12,
6396	/// C++11 [class.copy]p25, and C++11 [class.dtor]p5.
6397	bool SpecialMemberIsTrivial(
6398	CXXMethodDecl *MD, CXXSpecialMemberKind CSM,
6399	TrivialABIHandling TAH = TrivialABIHandling::IgnoreTrivialABI,
6400	bool Diagnose = false);
6401
6402	/// For a defaulted function, the kind of defaulted function that it is.
6403	class DefaultedFunctionKind {
6404	LLVM_PREFERRED_TYPE(CXXSpecialMemberKind)
6405	unsigned SpecialMember : `8`;
6406	unsigned Comparison : `8`;
6407
6408	public:
6409	DefaultedFunctionKind()
6410	: SpecialMember(llvm::to_underlying(E: CXXSpecialMemberKind::Invalid)),
6411	Comparison(llvm::to_underlying(E: DefaultedComparisonKind::None)) {}
6412	DefaultedFunctionKind(CXXSpecialMemberKind CSM)
6413	: SpecialMember(llvm::to_underlying(E: CSM)),
6414	Comparison(llvm::to_underlying(E: DefaultedComparisonKind::None)) {}
6415	DefaultedFunctionKind(DefaultedComparisonKind Comp)
6416	: SpecialMember(llvm::to_underlying(E: CXXSpecialMemberKind::Invalid)),
6417	Comparison(llvm::to_underlying(E: Comp)) {}
6418
6419	bool isSpecialMember() const {
6420	return static_cast<CXXSpecialMemberKind>(SpecialMember) !=
6421	CXXSpecialMemberKind::Invalid;
6422	}
6423	bool isComparison() const {
6424	return static_cast<DefaultedComparisonKind>(Comparison) !=
6425	DefaultedComparisonKind::None;
6426	}
6427
6428	explicit operator bool() const {
6429	return isSpecialMember() \|\| isComparison();
6430	}
6431
6432	CXXSpecialMemberKind asSpecialMember() const {
6433	return static_cast<CXXSpecialMemberKind>(SpecialMember);
6434	}
6435	DefaultedComparisonKind asComparison() const {
6436	return static_cast<DefaultedComparisonKind>(Comparison);
6437	}
6438
6439	/// Get the index of this function kind for use in diagnostics.
6440	unsigned getDiagnosticIndex() const {
6441	static_assert(llvm::to_underlying(E: CXXSpecialMemberKind::Invalid) >
6442	llvm::to_underlying(E: CXXSpecialMemberKind::Destructor),
6443	"invalid should have highest index");
6444	static_assert((unsigned)DefaultedComparisonKind::None == `0`,
6445	"none should be equal to zero");
6446	return SpecialMember + Comparison;
6447	}
6448	};
6449
6450	/// Determine the kind of defaulting that would be done for a given function.
6451	///
6452	/// If the function is both a default constructor and a copy / move
6453	/// constructor (due to having a default argument for the first parameter),
6454	/// this picks CXXSpecialMemberKind::DefaultConstructor.
6455	///
6456	/// FIXME: Check that case is properly handled by all callers.
6457	DefaultedFunctionKind getDefaultedFunctionKind(const FunctionDecl *FD);
6458
6459	/// Handle a C++11 empty-declaration and attribute-declaration.
6460	Decl ActOnEmptyDeclaration(Scope S, const ParsedAttributesView &AttrList,
6461	SourceLocation SemiLoc);
6462
6463	enum class CheckConstexprKind {
6464	/// Diagnose issues that are non-constant or that are extensions.
6465	Diagnose,
6466	/// Identify whether this function satisfies the formal rules for constexpr
6467	/// functions in the current lanugage mode (with no extensions).
6468	CheckValid
6469	};
6470
6471	// Check whether a function declaration satisfies the requirements of a
6472	// constexpr function definition or a constexpr constructor definition. If so,
6473	// return true. If not, produce appropriate diagnostics (unless asked not to
6474	// by Kind) and return false.
6475	//
6476	// This implements C++11 [dcl.constexpr]p3,4, as amended by DR1360.
6477	bool CheckConstexprFunctionDefinition(const FunctionDecl *FD,
6478	CheckConstexprKind Kind);
6479
6480	/// Diagnose methods which overload virtual methods in a base class
6481	/// without overriding any.
6482	void DiagnoseHiddenVirtualMethods(CXXMethodDecl *MD);
6483
6484	/// Check if a method overloads virtual methods in a base class without
6485	/// overriding any.
6486	void
6487	FindHiddenVirtualMethods(CXXMethodDecl *MD,
6488	SmallVectorImpl<CXXMethodDecl *> &OverloadedMethods);
6489	void
6490	NoteHiddenVirtualMethods(CXXMethodDecl *MD,
6491	SmallVectorImpl<CXXMethodDecl *> &OverloadedMethods);
6492
6493	/// ActOnParamDefaultArgument - Check whether the default argument
6494	/// provided for a function parameter is well-formed. If so, attach it
6495	/// to the parameter declaration.
6496	void ActOnParamDefaultArgument(Decl *param, SourceLocation EqualLoc,
6497	Expr *defarg);
6498
6499	/// ActOnParamUnparsedDefaultArgument - We've seen a default
6500	/// argument for a function parameter, but we can't parse it yet
6501	/// because we're inside a class definition. Note that this default
6502	/// argument will be parsed later.
6503	void ActOnParamUnparsedDefaultArgument(Decl *param, SourceLocation EqualLoc,
6504	SourceLocation ArgLoc);
6505
6506	/// ActOnParamDefaultArgumentError - Parsing or semantic analysis of
6507	/// the default argument for the parameter param failed.
6508	void ActOnParamDefaultArgumentError(Decl *param, SourceLocation EqualLoc,
6509	Expr *DefaultArg);
6510	ExprResult ConvertParamDefaultArgument(ParmVarDecl Param, Expr DefaultArg,
6511	SourceLocation EqualLoc);
6512	void SetParamDefaultArgument(ParmVarDecl Param, Expr DefaultArg,
6513	SourceLocation EqualLoc);
6514
6515	void ActOnPureSpecifier(Decl *D, SourceLocation PureSpecLoc);
6516	void SetDeclDeleted(Decl *dcl, SourceLocation DelLoc,
6517	StringLiteral Message = nullptr*);
6518	void SetDeclDefaulted(Decl *dcl, SourceLocation DefaultLoc);
6519
6520	void SetFunctionBodyKind(Decl *D, SourceLocation Loc, FnBodyKind BodyKind,
6521	StringLiteral DeletedMessage = nullptr*);
6522	void ActOnStartTrailingRequiresClause(Scope *S, Declarator &D);
6523	ExprResult ActOnFinishTrailingRequiresClause(ExprResult ConstraintExpr);
6524	ExprResult ActOnRequiresClause(ExprResult ConstraintExpr);
6525
6526	NamedDecl *
6527	ActOnDecompositionDeclarator(Scope *S, Declarator &D,
6528	MultiTemplateParamsArg TemplateParamLists);
6529	void DiagPlaceholderVariableDefinition(SourceLocation Loc);
6530	bool DiagRedefinedPlaceholderFieldDecl(SourceLocation Loc,
6531	RecordDecl *ClassDecl,
6532	const IdentifierInfo *Name);
6533
6534	UnsignedOrNone GetDecompositionElementCount(QualType DecompType,
6535	SourceLocation Loc);
6536	void CheckCompleteDecompositionDeclaration(DecompositionDecl *DD);
6537
6538	/// Stack containing information needed when in C++2a an 'auto' is encountered
6539	/// in a function declaration parameter type specifier in order to invent a
6540	/// corresponding template parameter in the enclosing abbreviated function
6541	/// template. This information is also present in LambdaScopeInfo, stored in
6542	/// the FunctionScopes stack.
6543	SmallVector<InventedTemplateParameterInfo, `4`> InventedParameterInfos;
6544
6545	/// FieldCollector - Collects CXXFieldDecls during parsing of C++ classes.
6546	std::unique_ptr<CXXFieldCollector> FieldCollector;
6547
6548	typedef llvm::SmallSetVector<const NamedDecl *, `16`> NamedDeclSetType;
6549	/// Set containing all declared private fields that are not used.
6550	NamedDeclSetType UnusedPrivateFields;
6551
6552	typedef llvm::SmallPtrSet<const CXXRecordDecl *, `8`> RecordDeclSetTy;
6553
6554	/// PureVirtualClassDiagSet - a set of class declarations which we have
6555	/// emitted a list of pure virtual functions. Used to prevent emitting the
6556	/// same list more than once.
6557	std::unique_ptr<RecordDeclSetTy> PureVirtualClassDiagSet;
6558
6559	typedef LazyVector<CXXConstructorDecl *, ExternalSemaSource,
6560	&ExternalSemaSource::ReadDelegatingConstructors, `2`, `2`>
6561	DelegatingCtorDeclsType;
6562
6563	/// All the delegating constructors seen so far in the file, used for
6564	/// cycle detection at the end of the TU.
6565	DelegatingCtorDeclsType DelegatingCtorDecls;
6566
6567	/// The C++ "std" namespace, where the standard library resides.
6568	LazyDeclPtr StdNamespace;
6569
6570	/// The C++ "std::initializer_list" template, which is defined in
6571	/// \<initializer_list>.
6572	ClassTemplateDecl *StdInitializerList;
6573
6574	/// The C++ "std::type_identity" template, which is defined in
6575	/// \<type_traits>.
6576	ClassTemplateDecl *StdTypeIdentity;
6577
6578	// Contains the locations of the beginning of unparsed default
6579	// argument locations.
6580	llvm::DenseMap<ParmVarDecl *, SourceLocation> UnparsedDefaultArgLocs;
6581
6582	/// UndefinedInternals - all the used, undefined objects which require a
6583	/// definition in this translation unit.
6584	llvm::MapVector<NamedDecl *, SourceLocation> UndefinedButUsed;
6585
6586	typedef llvm::PointerIntPair<CXXRecordDecl *, `3`, CXXSpecialMemberKind>
6587	SpecialMemberDecl;
6588
6589	/// The C++ special members which we are currently in the process of
6590	/// declaring. If this process recursively triggers the declaration of the
6591	/// same special member, we should act as if it is not yet declared.
6592	llvm::SmallPtrSet<SpecialMemberDecl, `4`> SpecialMembersBeingDeclared;
6593
6594	void NoteDeletedInheritingConstructor(CXXConstructorDecl *CD);
6595
6596	void ActOnDefaultCtorInitializers(Decl *CDtorDecl);
6597
6598	typedef ProcessingContextState ParsingClassState;
6599	ParsingClassState PushParsingClass() {
6600	ParsingClassDepth++;
6601	return DelayedDiagnostics.pushUndelayed();
6602	}
6603	void PopParsingClass(ParsingClassState state) {
6604	ParsingClassDepth--;
6605	DelayedDiagnostics.popUndelayed(state);
6606	}
6607
6608	ValueDecl tryLookupCtorInitMemberDecl(CXXRecordDecl ClassDecl,
6609	CXXScopeSpec &SS,
6610	ParsedType TemplateTypeTy,
6611	IdentifierInfo *MemberOrBase);
6612
6613	private:
6614	void setupImplicitSpecialMemberType(CXXMethodDecl *SpecialMem,
6615	QualType ResultTy,
6616	ArrayRef<QualType> Args);
6617	// Helper for ActOnFields to check for all function pointer members.
6618	bool EntirelyFunctionPointers(const RecordDecl *Record);
6619
6620	// A cache representing if we've fully checked the various comparison category
6621	// types stored in ASTContext. The bit-index corresponds to the integer value
6622	// of a ComparisonCategoryType enumerator.
6623	llvm::SmallBitVector FullyCheckedComparisonCategories;
6624
6625	/// Check if there is a field shadowing.
6626	void CheckShadowInheritedFields(const SourceLocation &Loc,
6627	DeclarationName FieldName,
6628	const CXXRecordDecl *RD,
6629	bool DeclIsField = true);
6630
6631	///@}
6632
6633	//
6634	//
6635	// -------------------------------------------------------------------------
6636	//
6637	//
6638
6639	/// \name C++ Exception Specifications
6640	/// Implementations are in SemaExceptionSpec.cpp
6641	///@{
6642
6643	public:
6644	/// All the overriding functions seen during a class definition
6645	/// that had their exception spec checks delayed, plus the overridden
6646	/// function.
6647	SmallVector<std::pair<const CXXMethodDecl , const* CXXMethodDecl *>, `2`>
6648	DelayedOverridingExceptionSpecChecks;
6649
6650	/// All the function redeclarations seen during a class definition that had
6651	/// their exception spec checks delayed, plus the prior declaration they
6652	/// should be checked against. Except during error recovery, the new decl
6653	/// should always be a friend declaration, as that's the only valid way to
6654	/// redeclare a special member before its class is complete.
6655	SmallVector<std::pair<FunctionDecl , FunctionDecl >, `2`>
6656	DelayedEquivalentExceptionSpecChecks;
6657
6658	/// Determine if we're in a case where we need to (incorrectly) eagerly
6659	/// parse an exception specification to work around a libstdc++ bug.
6660	bool isLibstdcxxEagerExceptionSpecHack(const Declarator &D);
6661
6662	/// Check the given noexcept-specifier, convert its expression, and compute
6663	/// the appropriate ExceptionSpecificationType.
6664	ExprResult ActOnNoexceptSpec(Expr *NoexceptExpr,
6665	ExceptionSpecificationType &EST);
6666
6667	CanThrowResult canThrow(const Stmt *E);
6668	/// Determine whether the callee of a particular function call can throw.
6669	/// E, D and Loc are all optional.
6670	static CanThrowResult canCalleeThrow(Sema &S, const Expr E, const* Decl *D,
6671	SourceLocation Loc = SourceLocation ());
6672	const FunctionProtoType *ResolveExceptionSpec(SourceLocation Loc,
6673	const FunctionProtoType *FPT);
6674	void UpdateExceptionSpec(FunctionDecl *FD,
6675	const FunctionProtoType::ExceptionSpecInfo &ESI);
6676
6677	/// CheckSpecifiedExceptionType - Check if the given type is valid in an
6678	/// exception specification. Incomplete types, or pointers to incomplete types
6679	/// other than void are not allowed.
6680	///
6681	/// \param[in,out] T The exception type. This will be decayed to a pointer
6682	/// type
6683	/// when the input is an array or a function type.
6684	bool CheckSpecifiedExceptionType(QualType &T, SourceRange Range);
6685
6686	/// CheckDistantExceptionSpec - Check if the given type is a pointer or
6687	/// pointer to member to a function with an exception specification. This
6688	/// means that it is invalid to add another level of indirection.
6689	bool CheckDistantExceptionSpec(QualType T);
6690	bool CheckEquivalentExceptionSpec(FunctionDecl Old, FunctionDecl New);
6691
6692	/// CheckEquivalentExceptionSpec - Check if the two types have equivalent
6693	/// exception specifications. Exception specifications are equivalent if
6694	/// they allow exactly the same set of exception types. It does not matter how
6695	/// that is achieved. See C++ [except.spec]p2.
6696	bool CheckEquivalentExceptionSpec(const FunctionProtoType *Old,
6697	SourceLocation OldLoc,
6698	const FunctionProtoType *New,
6699	SourceLocation NewLoc);
6700	bool CheckEquivalentExceptionSpec(const PartialDiagnostic &DiagID,
6701	const PartialDiagnostic &NoteID,
6702	const FunctionProtoType *Old,
6703	SourceLocation OldLoc,
6704	const FunctionProtoType *New,
6705	SourceLocation NewLoc);
6706	bool handlerCanCatch(QualType HandlerType, QualType ExceptionType);
6707
6708	/// CheckExceptionSpecSubset - Check whether the second function type's
6709	/// exception specification is a subset (or equivalent) of the first function
6710	/// type. This is used by override and pointer assignment checks.
6711	bool CheckExceptionSpecSubset(
6712	const PartialDiagnostic &DiagID, const PartialDiagnostic &NestedDiagID,
6713	const PartialDiagnostic &NoteID, const PartialDiagnostic &NoThrowDiagID,
6714	const FunctionProtoType Superset, bool* SkipSupersetFirstParameter,
6715	SourceLocation SuperLoc, const FunctionProtoType *Subset,
6716	bool SkipSubsetFirstParameter, SourceLocation SubLoc);
6717
6718	/// CheckParamExceptionSpec - Check if the parameter and return types of the
6719	/// two functions have equivalent exception specs. This is part of the
6720	/// assignment and override compatibility check. We do not check the
6721	/// parameters of parameter function pointers recursively, as no sane
6722	/// programmer would even be able to write such a function type.
6723	bool CheckParamExceptionSpec(
6724	const PartialDiagnostic &NestedDiagID, const PartialDiagnostic &NoteID,
6725	const FunctionProtoType Target, bool* SkipTargetFirstParameter,
6726	SourceLocation TargetLoc, const FunctionProtoType *Source,
6727	bool SkipSourceFirstParameter, SourceLocation SourceLoc);
6728
6729	bool CheckExceptionSpecCompatibility(Expr *From, QualType ToType);
6730
6731	/// CheckOverridingFunctionExceptionSpec - Checks whether the exception
6732	/// spec is a subset of base spec.
6733	bool CheckOverridingFunctionExceptionSpec(const CXXMethodDecl *New,
6734	const CXXMethodDecl *Old);
6735
6736	///@}
6737
6738	//
6739	//
6740	// -------------------------------------------------------------------------
6741	//
6742	//
6743
6744	/// \name Expressions
6745	/// Implementations are in SemaExpr.cpp
6746	///@{
6747
6748	public:
6749	/// Describes how the expressions currently being parsed are
6750	/// evaluated at run-time, if at all.
6751	enum class ExpressionEvaluationContext {
6752	/// The current expression and its subexpressions occur within an
6753	/// unevaluated operand (C++11 [expr]p7), such as the subexpression of
6754	/// \c sizeof, where the type of the expression may be significant but
6755	/// no code will be generated to evaluate the value of the expression at
6756	/// run time.
6757	Unevaluated,
6758
6759	/// The current expression occurs within a braced-init-list within
6760	/// an unevaluated operand. This is mostly like a regular unevaluated
6761	/// context, except that we still instantiate constexpr functions that are
6762	/// referenced here so that we can perform narrowing checks correctly.
6763	UnevaluatedList,
6764
6765	/// The current expression occurs within a discarded statement.
6766	/// This behaves largely similarly to an unevaluated operand in preventing
6767	/// definitions from being required, but not in other ways.
6768	DiscardedStatement,
6769
6770	/// The current expression occurs within an unevaluated
6771	/// operand that unconditionally permits abstract references to
6772	/// fields, such as a SIZE operator in MS-style inline assembly.
6773	UnevaluatedAbstract,
6774
6775	/// The current context is "potentially evaluated" in C++11 terms,
6776	/// but the expression is evaluated at compile-time (like the values of
6777	/// cases in a switch statement).
6778	ConstantEvaluated,
6779
6780	/// In addition of being constant evaluated, the current expression
6781	/// occurs in an immediate function context - either a consteval function
6782	/// or a consteval if statement.
6783	ImmediateFunctionContext,
6784
6785	/// The current expression is potentially evaluated at run time,
6786	/// which means that code may be generated to evaluate the value of the
6787	/// expression at run time.
6788	PotentiallyEvaluated,
6789
6790	/// The current expression is potentially evaluated, but any
6791	/// declarations referenced inside that expression are only used if
6792	/// in fact the current expression is used.
6793	///
6794	/// This value is used when parsing default function arguments, for which
6795	/// we would like to provide diagnostics (e.g., passing non-POD arguments
6796	/// through varargs) but do not want to mark declarations as "referenced"
6797	/// until the default argument is used.
6798	PotentiallyEvaluatedIfUsed
6799	};
6800
6801	/// Store a set of either DeclRefExprs or MemberExprs that contain a reference
6802	/// to a variable (constant) that may or may not be odr-used in this Expr, and
6803	/// we won't know until all lvalue-to-rvalue and discarded value conversions
6804	/// have been applied to all subexpressions of the enclosing full expression.
6805	/// This is cleared at the end of each full expression.
6806	using MaybeODRUseExprSet = llvm::SmallSetVector<Expr *, `4`>;
6807	MaybeODRUseExprSet MaybeODRUseExprs;
6808
6809	using ImmediateInvocationCandidate = llvm::PointerIntPair<ConstantExpr *, `1`>;
6810
6811	/// Data structure used to record current or nested
6812	/// expression evaluation contexts.
6813	struct ExpressionEvaluationContextRecord {
6814	/// The expression evaluation context.
6815	ExpressionEvaluationContext Context;
6816
6817	/// Whether the enclosing context needed a cleanup.
6818	CleanupInfo ParentCleanup;
6819
6820	/// The number of active cleanup objects when we entered
6821	/// this expression evaluation context.
6822	unsigned NumCleanupObjects;
6823
6824	MaybeODRUseExprSet SavedMaybeODRUseExprs;
6825
6826	/// The lambdas that are present within this context, if it
6827	/// is indeed an unevaluated context.
6828	SmallVector<LambdaExpr *, `2`> Lambdas;
6829
6830	/// The declaration that provides context for lambda expressions
6831	/// and block literals if the normal declaration context does not
6832	/// suffice, e.g., in a default function argument.
6833	Decl *ManglingContextDecl;
6834
6835	/// Declaration for initializer if one is currently being
6836	/// parsed. Used when an expression has a possibly unreachable
6837	/// diagnostic to reference the declaration as a whole.
6838	VarDecl DeclForInitializer = nullptr*;
6839
6840	/// If we are processing a decltype type, a set of call expressions
6841	/// for which we have deferred checking the completeness of the return type.
6842	SmallVector<CallExpr *, `8`> DelayedDecltypeCalls;
6843
6844	/// If we are processing a decltype type, a set of temporary binding
6845	/// expressions for which we have deferred checking the destructor.
6846	SmallVector<CXXBindTemporaryExpr *, `8`> DelayedDecltypeBinds;
6847
6848	llvm::SmallPtrSet<const Expr *, `8`> PossibleDerefs;
6849
6850	/// Expressions appearing as the LHS of a volatile assignment in this
6851	/// context. We produce a warning for these when popping the context if
6852	/// they are not discarded-value expressions nor unevaluated operands.
6853	SmallVector<Expr *, `2`> VolatileAssignmentLHSs;
6854
6855	/// Set of candidates for starting an immediate invocation.
6856	llvm::SmallVector<ImmediateInvocationCandidate, `4`>
6857	ImmediateInvocationCandidates;
6858
6859	/// Set of DeclRefExprs referencing a consteval function when used in a
6860	/// context not already known to be immediately invoked.
6861	llvm::SmallPtrSet<DeclRefExpr *, `4`> ReferenceToConsteval;
6862
6863	/// P2718R0 - Lifetime extension in range-based for loops.
6864	/// MaterializeTemporaryExprs in for-range-init expressions which need to
6865	/// extend lifetime. Add MaterializeTemporaryExpr if the value of*
6866	/// InLifetimeExtendingContext is true.
6867	SmallVector<MaterializeTemporaryExpr *, `8`> ForRangeLifetimeExtendTemps;
6868
6869	/// Small set of gathered accesses to potentially misaligned members
6870	/// due to the packed attribute.
6871	SmallVector<MisalignedMember, `4`> MisalignedMembers;
6872
6873	/// \brief Describes whether we are in an expression constext which we have
6874	/// to handle differently.
6875	enum ExpressionKind {
6876	EK_Decltype,
6877	EK_TemplateArgument,
6878	EK_AttrArgument,
6879	EK_VariableInit,
6880	EK_Other
6881	} ExprContext;
6882
6883	// A context can be nested in both a discarded statement context and
6884	// an immediate function context, so they need to be tracked independently.
6885	bool InDiscardedStatement;
6886	bool InImmediateFunctionContext;
6887	bool InImmediateEscalatingFunctionContext;
6888
6889	bool IsCurrentlyCheckingDefaultArgumentOrInitializer = false;
6890
6891	// We are in a constant context, but we also allow
6892	// non constant expressions, for example for array bounds (which may be
6893	// VLAs).
6894	bool InConditionallyConstantEvaluateContext = false;
6895
6896	/// Whether we are currently in a context in which all temporaries must be
6897	/// lifetime-extended, even if they're not bound to a reference (for
6898	/// example, in a for-range initializer).
6899	bool InLifetimeExtendingContext = false;
6900
6901	/// Whether evaluating an expression for a switch case label.
6902	bool IsCaseExpr = false;
6903
6904	/// Whether we should rebuild CXXDefaultArgExpr and CXXDefaultInitExpr.
6905	bool RebuildDefaultArgOrDefaultInit = false;
6906
6907	// When evaluating immediate functions in the initializer of a default
6908	// argument or default member initializer, this is the declaration whose
6909	// default initializer is being evaluated and the location of the call
6910	// or constructor definition.
6911	struct InitializationContext {
6912	InitializationContext(SourceLocation Loc, ValueDecl *Decl,
6913	DeclContext *Context)
6914	: Loc (Loc), Decl(Decl), Context(Context) {
6915	assert(Decl && Context && "invalid initialization context");
6916	}
6917
6918	SourceLocation Loc;
6919	ValueDecl Decl = nullptr*;
6920	DeclContext Context = nullptr*;
6921	};
6922	std::optional<InitializationContext> DelayedDefaultInitializationContext;
6923
6924	ExpressionEvaluationContextRecord(ExpressionEvaluationContext Context,
6925	unsigned NumCleanupObjects,
6926	CleanupInfo ParentCleanup,
6927	Decl *ManglingContextDecl,
6928	ExpressionKind ExprContext)
6929	: Context(Context), ParentCleanup (ParentCleanup),
6930	NumCleanupObjects(NumCleanupObjects),
6931	ManglingContextDecl(ManglingContextDecl), ExprContext(ExprContext),
6932	InDiscardedStatement(false), InImmediateFunctionContext(false),
6933	InImmediateEscalatingFunctionContext(false) {}
6934
6935	bool isUnevaluated() const {
6936	return Context == ExpressionEvaluationContext::Unevaluated \|\|
6937	Context == ExpressionEvaluationContext::UnevaluatedAbstract \|\|
6938	Context == ExpressionEvaluationContext::UnevaluatedList;
6939	}
6940
6941	bool isPotentiallyEvaluated() const {
6942	return Context == ExpressionEvaluationContext::PotentiallyEvaluated \|\|
6943	Context ==
6944	ExpressionEvaluationContext::PotentiallyEvaluatedIfUsed \|\|
6945	Context == ExpressionEvaluationContext::ConstantEvaluated;
6946	}
6947
6948	bool isConstantEvaluated() const {
6949	return Context == ExpressionEvaluationContext::ConstantEvaluated \|\|
6950	Context == ExpressionEvaluationContext::ImmediateFunctionContext;
6951	}
6952
6953	bool isImmediateFunctionContext() const {
6954	return Context == ExpressionEvaluationContext::ImmediateFunctionContext \|\|
6955	(Context == ExpressionEvaluationContext::DiscardedStatement &&
6956	InImmediateFunctionContext) \|\|
6957	// C++23 [expr.const]p14:
6958	// An expression or conversion is in an immediate function
6959	// context if it is potentially evaluated and either:
6960	// its innermost enclosing non-block scope is a function*
6961	// parameter scope of an immediate function, or
6962	// its enclosing statement is enclosed by the compound-*
6963	// statement of a consteval if statement.
6964	(Context == ExpressionEvaluationContext::PotentiallyEvaluated &&
6965	InImmediateFunctionContext);
6966	}
6967
6968	bool isDiscardedStatementContext() const {
6969	return Context == ExpressionEvaluationContext::DiscardedStatement \|\|
6970	((Context ==
6971	ExpressionEvaluationContext::ImmediateFunctionContext \|\|
6972	isPotentiallyEvaluated()) &&
6973	InDiscardedStatement);
6974	}
6975	};
6976
6977	const ExpressionEvaluationContextRecord &currentEvaluationContext() const {
6978	assert(!ExprEvalContexts.empty() &&
6979	"Must be in an expression evaluation context");
6980	return ExprEvalContexts.back();
6981	}
6982
6983	ExpressionEvaluationContextRecord &currentEvaluationContext() {
6984	assert(!ExprEvalContexts.empty() &&
6985	"Must be in an expression evaluation context");
6986	return ExprEvalContexts.back();
6987	}
6988
6989	ExpressionEvaluationContextRecord &parentEvaluationContext() {
6990	assert(ExprEvalContexts.size() >= `2` &&
6991	"Must be in an expression evaluation context");
6992	return ExprEvalContexts [ExprEvalContexts.size() - `2`];
6993	}
6994
6995	const ExpressionEvaluationContextRecord &parentEvaluationContext() const {
6996	return const_cast<Sema >(this*)->parentEvaluationContext();
6997	}
6998
6999	bool isAttrContext() const {
7000	return ExprEvalContexts.back().ExprContext ==
7001	ExpressionEvaluationContextRecord::ExpressionKind::EK_AttrArgument;
7002	}
7003
7004	/// Increment when we find a reference; decrement when we find an ignored
7005	/// assignment. Ultimately the value is 0 if every reference is an ignored
7006	/// assignment.
7007	llvm::DenseMap<const VarDecl , int*> RefsMinusAssignments;
7008
7009	/// Used to control the generation of ExprWithCleanups.
7010	CleanupInfo Cleanup;
7011
7012	/// ExprCleanupObjects - This is the stack of objects requiring
7013	/// cleanup that are created by the current full expression.
7014	SmallVector<ExprWithCleanups::CleanupObject, `8`> ExprCleanupObjects;
7015
7016	/// Determine whether the use of this declaration is valid, without
7017	/// emitting diagnostics.
7018	bool CanUseDecl(NamedDecl D, bool* TreatUnavailableAsInvalid);
7019	// A version of DiagnoseUseOfDecl that should be used if overload resolution
7020	// has been used to find this declaration, which means we don't have to bother
7021	// checking the trailing requires clause.
7022	bool DiagnoseUseOfOverloadedDecl(NamedDecl *D, SourceLocation Loc) {
7023	return DiagnoseUseOfDecl(
7024	D, Locs: Loc, /UnknownObjCClass=/UnknownObjCClass: nullptr, /ObjCPropertyAccess=/ObjCPropertyAccess: false,
7025	/AvoidPartialAvailabilityChecks=/AvoidPartialAvailabilityChecks: false, /ClassReceiver=/ClassReceiver: nullptr,
7026	/SkipTrailingRequiresClause=/SkipTrailingRequiresClause: true);
7027	}
7028
7029	/// Determine whether the use of this declaration is valid, and
7030	/// emit any corresponding diagnostics.
7031	///
7032	/// This routine diagnoses various problems with referencing
7033	/// declarations that can occur when using a declaration. For example,
7034	/// it might warn if a deprecated or unavailable declaration is being
7035	/// used, or produce an error (and return true) if a C++0x deleted
7036	/// function is being used.
7037	///
7038	/// \returns true if there was an error (this declaration cannot be
7039	/// referenced), false otherwise.
7040	bool DiagnoseUseOfDecl(NamedDecl *D, ArrayRef<SourceLocation> Locs,
7041	const ObjCInterfaceDecl UnknownObjCClass = nullptr*,
7042	bool ObjCPropertyAccess = false,
7043	bool AvoidPartialAvailabilityChecks = false,
7044	ObjCInterfaceDecl ClassReceiver = nullptr*,
7045	bool SkipTrailingRequiresClause = false);
7046
7047	/// Emit a note explaining that this function is deleted.
7048	void NoteDeletedFunction(FunctionDecl *FD);
7049
7050	/// DiagnoseSentinelCalls - This routine checks whether a call or
7051	/// message-send is to a declaration with the sentinel attribute, and
7052	/// if so, it checks that the requirements of the sentinel are
7053	/// satisfied.
7054	void DiagnoseSentinelCalls(const NamedDecl *D, SourceLocation Loc,
7055	ArrayRef<Expr *> Args);
7056
7057	void PushExpressionEvaluationContext(
7058	ExpressionEvaluationContext NewContext, Decl LambdaContextDecl = nullptr*,
7059	ExpressionEvaluationContextRecord::ExpressionKind Type =
7060	ExpressionEvaluationContextRecord::EK_Other);
7061
7062	void PushExpressionEvaluationContextForFunction(
7063	ExpressionEvaluationContext NewContext, FunctionDecl *FD);
7064
7065	enum ReuseLambdaContextDecl_t { ReuseLambdaContextDecl };
7066	void PushExpressionEvaluationContext(
7067	ExpressionEvaluationContext NewContext, ReuseLambdaContextDecl_t,
7068	ExpressionEvaluationContextRecord::ExpressionKind Type =
7069	ExpressionEvaluationContextRecord::EK_Other);
7070	void PopExpressionEvaluationContext();
7071
7072	void DiscardCleanupsInEvaluationContext();
7073
7074	ExprResult TransformToPotentiallyEvaluated(Expr *E);
7075	TypeSourceInfo TransformToPotentiallyEvaluated(TypeSourceInfo TInfo);
7076	ExprResult HandleExprEvaluationContextForTypeof(Expr *E);
7077
7078	/// Check whether E, which is either a discarded-value expression or an
7079	/// unevaluated operand, is a simple-assignment to a volatlie-qualified
7080	/// lvalue, and if so, remove it from the list of volatile-qualified
7081	/// assignments that we are going to warn are deprecated.
7082	void CheckUnusedVolatileAssignment(Expr *E);
7083
7084	ExprResult ActOnConstantExpression(ExprResult Res);
7085
7086	// Functions for marking a declaration referenced. These functions also
7087	// contain the relevant logic for marking if a reference to a function or
7088	// variable is an odr-use (in the C++11 sense). There are separate variants
7089	// for expressions referring to a decl; these exist because odr-use marking
7090	// needs to be delayed for some constant variables when we build one of the
7091	// named expressions.
7092	//
7093	// MightBeOdrUse indicates whether the use could possibly be an odr-use, and
7094	// should usually be true. This only needs to be set to false if the lack of
7095	// odr-use cannot be determined from the current context (for instance,
7096	// because the name denotes a virtual function and was written without an
7097	// explicit nested-name-specifier).
7098	void MarkAnyDeclReferenced(SourceLocation Loc, Decl D, bool* MightBeOdrUse);
7099
7100	/// Mark a function referenced, and check whether it is odr-used
7101	/// (C++ [basic.def.odr]p2, C99 6.9p3)
7102	void MarkFunctionReferenced(SourceLocation Loc, FunctionDecl *Func,
7103	bool MightBeOdrUse = true);
7104
7105	/// Mark a variable referenced, and check whether it is odr-used
7106	/// (C++ [basic.def.odr]p2, C99 6.9p3). Note that this should not be
7107	/// used directly for normal expressions referring to VarDecl.
7108	void MarkVariableReferenced(SourceLocation Loc, VarDecl *Var);
7109
7110	/// Perform reference-marking and odr-use handling for a DeclRefExpr.
7111	///
7112	/// Note, this may change the dependence of the DeclRefExpr, and so needs to
7113	/// be handled with care if the DeclRefExpr is not newly-created.
7114	void MarkDeclRefReferenced(DeclRefExpr E, const* Expr Base = nullptr*);
7115
7116	/// Perform reference-marking and odr-use handling for a MemberExpr.
7117	void MarkMemberReferenced(MemberExpr *E);
7118
7119	/// Perform reference-marking and odr-use handling for a FunctionParmPackExpr.
7120	void MarkFunctionParmPackReferenced(FunctionParmPackExpr *E);
7121	void MarkCaptureUsedInEnclosingContext(ValueDecl *Capture, SourceLocation Loc,
7122	unsigned CapturingScopeIndex);
7123
7124	ExprResult CheckLValueToRValueConversionOperand(Expr *E);
7125	void CleanupVarDeclMarking();
7126
7127	/// Try to capture the given variable.
7128	///
7129	/// \param Var The variable to capture.
7130	///
7131	/// \param Loc The location at which the capture occurs.
7132	///
7133	/// \param Kind The kind of capture, which may be implicit (for either a
7134	/// block or a lambda), or explicit by-value or by-reference (for a lambda).
7135	///
7136	/// \param EllipsisLoc The location of the ellipsis, if one is provided in
7137	/// an explicit lambda capture.
7138	///
7139	/// \param BuildAndDiagnose Whether we are actually supposed to add the
7140	/// captures or diagnose errors. If false, this routine merely check whether
7141	/// the capture can occur without performing the capture itself or complaining
7142	/// if the variable cannot be captured.
7143	///
7144	/// \param CaptureType Will be set to the type of the field used to capture
7145	/// this variable in the innermost block or lambda. Only valid when the
7146	/// variable can be captured.
7147	///
7148	/// \param DeclRefType Will be set to the type of a reference to the capture
7149	/// from within the current scope. Only valid when the variable can be
7150	/// captured.
7151	///
7152	/// \param FunctionScopeIndexToStopAt If non-null, it points to the index
7153	/// of the FunctionScopeInfo stack beyond which we do not attempt to capture.
7154	/// This is useful when enclosing lambdas must speculatively capture
7155	/// variables that may or may not be used in certain specializations of
7156	/// a nested generic lambda.
7157	///
7158	/// \returns true if an error occurred (i.e., the variable cannot be
7159	/// captured) and false if the capture succeeded.
7160	bool tryCaptureVariable(ValueDecl *Var, SourceLocation Loc,
7161	TryCaptureKind Kind, SourceLocation EllipsisLoc,
7162	bool BuildAndDiagnose, QualType &CaptureType,
7163	QualType &DeclRefType,
7164	const unsigned *const FunctionScopeIndexToStopAt);
7165
7166	/// Try to capture the given variable.
7167	bool tryCaptureVariable(ValueDecl *Var, SourceLocation Loc,
7168	TryCaptureKind Kind = TryCaptureKind::Implicit,
7169	SourceLocation EllipsisLoc = SourceLocation ());
7170
7171	/// Checks if the variable must be captured.
7172	bool NeedToCaptureVariable(ValueDecl *Var, SourceLocation Loc);
7173
7174	/// Given a variable, determine the type that a reference to that
7175	/// variable will have in the given scope.
7176	QualType getCapturedDeclRefType(ValueDecl *Var, SourceLocation Loc);
7177
7178	/// Mark all of the declarations referenced within a particular AST node as
7179	/// referenced. Used when template instantiation instantiates a non-dependent
7180	/// type -- entities referenced by the type are now referenced.
7181	void MarkDeclarationsReferencedInType(SourceLocation Loc, QualType T);
7182
7183	/// Mark any declarations that appear within this expression or any
7184	/// potentially-evaluated subexpressions as "referenced".
7185	///
7186	/// \param SkipLocalVariables If true, don't mark local variables as
7187	/// 'referenced'.
7188	/// \param StopAt Subexpressions that we shouldn't recurse into.
7189	void MarkDeclarationsReferencedInExpr(Expr *E,
7190	bool SkipLocalVariables = false,
7191	ArrayRef<const Expr *> StopAt = {});
7192
7193	/// Try to convert an expression \p E to type \p Ty. Returns the result of the
7194	/// conversion.
7195	ExprResult tryConvertExprToType(Expr *E, QualType Ty);
7196
7197	/// Conditionally issue a diagnostic based on the statements's reachability
7198	/// analysis.
7199	///
7200	/// \param Stmts If Stmts is non-empty, delay reporting the diagnostic until
7201	/// the function body is parsed, and then do a basic reachability analysis to
7202	/// determine if the statement is reachable. If it is unreachable, the
7203	/// diagnostic will not be emitted.
7204	bool DiagIfReachable(SourceLocation Loc, ArrayRef<const Stmt *> Stmts,
7205	const PartialDiagnostic &PD);
7206
7207	/// Conditionally issue a diagnostic based on the current
7208	/// evaluation context.
7209	///
7210	/// \param Statement If Statement is non-null, delay reporting the
7211	/// diagnostic until the function body is parsed, and then do a basic
7212	/// reachability analysis to determine if the statement is reachable.
7213	/// If it is unreachable, the diagnostic will not be emitted.
7214	bool DiagRuntimeBehavior(SourceLocation Loc, const Stmt *Statement,
7215	const PartialDiagnostic &PD);
7216	/// Similar, but diagnostic is only produced if all the specified statements
7217	/// are reachable.
7218	bool DiagRuntimeBehavior(SourceLocation Loc, ArrayRef<const Stmt *> Stmts,
7219	const PartialDiagnostic &PD);
7220
7221	// Primary Expressions.
7222	SourceRange getExprRange(Expr E) const*;
7223
7224	ExprResult ActOnIdExpression(Scope *S, CXXScopeSpec &SS,
7225	SourceLocation TemplateKWLoc, UnqualifiedId &Id,
7226	bool HasTrailingLParen, bool IsAddressOfOperand,
7227	CorrectionCandidateCallback CCC = nullptr*,
7228	bool IsInlineAsmIdentifier = false,
7229	Token KeywordReplacement = nullptr*);
7230
7231	/// Decomposes the given name into a DeclarationNameInfo, its location, and
7232	/// possibly a list of template arguments.
7233	///
7234	/// If this produces template arguments, it is permitted to call
7235	/// DecomposeTemplateName.
7236	///
7237	/// This actually loses a lot of source location information for
7238	/// non-standard name kinds; we should consider preserving that in
7239	/// some way.
7240	void DecomposeUnqualifiedId(const UnqualifiedId &Id,
7241	TemplateArgumentListInfo &Buffer,
7242	DeclarationNameInfo &NameInfo,
7243	const TemplateArgumentListInfo *&TemplateArgs);
7244
7245	/// Diagnose a lookup that found results in an enclosing class during error
7246	/// recovery. This usually indicates that the results were found in a
7247	/// dependent base class that could not be searched as part of a template
7248	/// definition. Always issues a diagnostic (though this may be only a warning
7249	/// in MS compatibility mode).
7250	///
7251	/// Return \c true if the error is unrecoverable, or \c false if the caller
7252	/// should attempt to recover using these lookup results.
7253	bool DiagnoseDependentMemberLookup(const LookupResult &R);
7254
7255	/// Diagnose an empty lookup.
7256	///
7257	/// \return false if new lookup candidates were found
7258	bool
7259	DiagnoseEmptyLookup(Scope *S, CXXScopeSpec &SS, LookupResult &R,
7260	CorrectionCandidateCallback &CCC,
7261	TemplateArgumentListInfo ExplicitTemplateArgs = nullptr*,
7262	ArrayRef<Expr *> Args = {},
7263	DeclContext LookupCtx = nullptr*);
7264
7265	/// If \p D cannot be odr-used in the current expression evaluation context,
7266	/// return a reason explaining why. Otherwise, return NOUR_None.
7267	NonOdrUseReason getNonOdrUseReasonInCurrentContext(ValueDecl *D);
7268
7269	DeclRefExpr BuildDeclRefExpr(ValueDecl D, QualType Ty, ExprValueKind VK,
7270	SourceLocation Loc,
7271	const CXXScopeSpec SS = nullptr*);
7272	DeclRefExpr *
7273	BuildDeclRefExpr(ValueDecl *D, QualType Ty, ExprValueKind VK,
7274	const DeclarationNameInfo &NameInfo,
7275	const CXXScopeSpec SS = nullptr*,
7276	NamedDecl FoundD = nullptr*,
7277	SourceLocation TemplateKWLoc = SourceLocation (),
7278	const TemplateArgumentListInfo TemplateArgs = nullptr*);
7279
7280	/// BuildDeclRefExpr - Build an expression that references a
7281	/// declaration that does not require a closure capture.
7282	DeclRefExpr *
7283	BuildDeclRefExpr(ValueDecl *D, QualType Ty, ExprValueKind VK,
7284	const DeclarationNameInfo &NameInfo,
7285	NestedNameSpecifierLoc NNS, NamedDecl FoundD = nullptr*,
7286	SourceLocation TemplateKWLoc = SourceLocation (),
7287	const TemplateArgumentListInfo TemplateArgs = nullptr*);
7288
7289	bool UseArgumentDependentLookup(const CXXScopeSpec &SS, const LookupResult &R,
7290	bool HasTrailingLParen);
7291
7292	/// BuildQualifiedDeclarationNameExpr - Build a C++ qualified
7293	/// declaration name, generally during template instantiation.
7294	/// There's a large number of things which don't need to be done along
7295	/// this path.
7296	ExprResult BuildQualifiedDeclarationNameExpr(
7297	CXXScopeSpec &SS, const DeclarationNameInfo &NameInfo,
7298	bool IsAddressOfOperand, TypeSourceInfo RecoveryTSI = nullptr**);
7299
7300	ExprResult BuildDeclarationNameExpr(const CXXScopeSpec &SS, LookupResult &R,
7301	bool NeedsADL,
7302	bool AcceptInvalidDecl = false);
7303
7304	/// Complete semantic analysis for a reference to the given declaration.
7305	ExprResult BuildDeclarationNameExpr(
7306	const CXXScopeSpec &SS, const DeclarationNameInfo &NameInfo, NamedDecl *D,
7307	NamedDecl FoundD = nullptr*,
7308	const TemplateArgumentListInfo TemplateArgs = nullptr*,
7309	bool AcceptInvalidDecl = false);
7310
7311	// ExpandFunctionLocalPredefinedMacros - Returns a new vector of Tokens,
7312	// where Tokens representing function local predefined macros (such as
7313	// __FUNCTION__) are replaced (expanded) with string-literal Tokens.
7314	std::vector<Token> ExpandFunctionLocalPredefinedMacros(ArrayRef<Token> Toks);
7315
7316	ExprResult BuildPredefinedExpr(SourceLocation Loc, PredefinedIdentKind IK);
7317	ExprResult ActOnPredefinedExpr(SourceLocation Loc, tok::TokenKind Kind);
7318	ExprResult ActOnIntegerConstant(SourceLocation Loc, int64_t Val);
7319
7320	bool CheckLoopHintExpr(Expr E, SourceLocation Loc, bool* AllowZero);
7321
7322	ExprResult ActOnNumericConstant(const Token &Tok, Scope UDLScope = nullptr*);
7323	ExprResult ActOnCharacterConstant(const Token &Tok,
7324	Scope UDLScope = nullptr*);
7325	ExprResult ActOnParenExpr(SourceLocation L, SourceLocation R, Expr *E);
7326	ExprResult ActOnParenListExpr(SourceLocation L, SourceLocation R,
7327	MultiExprArg Val);
7328	ExprResult ActOnCXXParenListInitExpr(ArrayRef<Expr *> Args, QualType T,
7329	unsigned NumUserSpecifiedExprs,
7330	SourceLocation InitLoc,
7331	SourceLocation LParenLoc,
7332	SourceLocation RParenLoc);
7333
7334	/// ActOnStringLiteral - The specified tokens were lexed as pasted string
7335	/// fragments (e.g. "foo" "bar" L"baz"). The result string has to handle
7336	/// string concatenation ([C99 5.1.1.2, translation phase #6]), so it may come
7337	/// from multiple tokens. However, the common case is that StringToks points
7338	/// to one string.
7339	ExprResult ActOnStringLiteral(ArrayRef<Token> StringToks,
7340	Scope UDLScope = nullptr*);
7341
7342	ExprResult ActOnUnevaluatedStringLiteral(ArrayRef<Token> StringToks);
7343
7344	/// ControllingExprOrType is either an opaque pointer coming out of a
7345	/// ParsedType or an Expr . FIXME: it'd be better to split this interface*
7346	/// into two so we don't take a void , but that's awkward because one of*
7347	/// the operands is either a ParsedType or an Expr , which doesn't lend*
7348	/// itself to generic code very well.
7349	ExprResult ActOnGenericSelectionExpr(SourceLocation KeyLoc,
7350	SourceLocation DefaultLoc,
7351	SourceLocation RParenLoc,
7352	bool PredicateIsExpr,
7353	void *ControllingExprOrType,
7354	ArrayRef<ParsedType> ArgTypes,
7355	ArrayRef<Expr *> ArgExprs);
7356	/// ControllingExprOrType is either a TypeSourceInfo or an Expr . FIXME:
7357	/// it'd be better to split this interface into two so we don't take a
7358	/// void , but see the FIXME on ActOnGenericSelectionExpr as to why that*
7359	/// isn't a trivial change.
7360	ExprResult CreateGenericSelectionExpr(SourceLocation KeyLoc,
7361	SourceLocation DefaultLoc,
7362	SourceLocation RParenLoc,
7363	bool PredicateIsExpr,
7364	void *ControllingExprOrType,
7365	ArrayRef<TypeSourceInfo *> Types,
7366	ArrayRef<Expr *> Exprs);
7367
7368	// Binary/Unary Operators. 'Tok' is the token for the operator.
7369	ExprResult CreateBuiltinUnaryOp(SourceLocation OpLoc, UnaryOperatorKind Opc,
7370	Expr InputExpr, bool* IsAfterAmp = false);
7371	ExprResult BuildUnaryOp(Scope *S, SourceLocation OpLoc, UnaryOperatorKind Opc,
7372	Expr Input, bool* IsAfterAmp = false);
7373
7374	/// Unary Operators. 'Tok' is the token for the operator.
7375	ExprResult ActOnUnaryOp(Scope *S, SourceLocation OpLoc, tok::TokenKind Op,
7376	Expr Input, bool* IsAfterAmp = false);
7377
7378	/// Determine whether the given expression is a qualified member
7379	/// access expression, of a form that could be turned into a pointer to member
7380	/// with the address-of operator.
7381	bool isQualifiedMemberAccess(Expr *E);
7382	bool CheckUseOfCXXMethodAsAddressOfOperand(SourceLocation OpLoc,
7383	const Expr *Op,
7384	const CXXMethodDecl *MD);
7385
7386	/// CheckAddressOfOperand - The operand of & must be either a function
7387	/// designator or an lvalue designating an object. If it is an lvalue, the
7388	/// object cannot be declared with storage class register or be a bit field.
7389	/// Note: The usual conversions are not* applied to the operand of the &*
7390	/// operator (C99 6.3.2.1p[2-4]), and its result is never an lvalue.
7391	/// In C++, the operand might be an overloaded function name, in which case
7392	/// we allow the '&' but retain the overloaded-function type.
7393	QualType CheckAddressOfOperand(ExprResult &Operand, SourceLocation OpLoc);
7394
7395	/// ActOnAlignasTypeArgument - Handle @c alignas(type-id) and @c
7396	/// _Alignas(type-name) .
7397	/// [dcl.align] An alignment-specifier of the form
7398	/// alignas(type-id) has the same effect as alignas(alignof(type-id)).
7399	///
7400	/// [N1570 6.7.5] _Alignas(type-name) is equivalent to
7401	/// _Alignas(_Alignof(type-name)).
7402	bool ActOnAlignasTypeArgument(StringRef KWName, ParsedType Ty,
7403	SourceLocation OpLoc, SourceRange R);
7404	bool CheckAlignasTypeArgument(StringRef KWName, TypeSourceInfo *TInfo,
7405	SourceLocation OpLoc, SourceRange R);
7406
7407	/// Build a sizeof or alignof expression given a type operand.
7408	ExprResult CreateUnaryExprOrTypeTraitExpr(TypeSourceInfo *TInfo,
7409	SourceLocation OpLoc,
7410	UnaryExprOrTypeTrait ExprKind,
7411	SourceRange R);
7412
7413	/// Build a sizeof or alignof expression given an expression
7414	/// operand.
7415	ExprResult CreateUnaryExprOrTypeTraitExpr(Expr *E, SourceLocation OpLoc,
7416	UnaryExprOrTypeTrait ExprKind);
7417
7418	/// ActOnUnaryExprOrTypeTraitExpr - Handle @c sizeof(type) and @c sizeof @c
7419	/// expr and the same for @c alignof and @c __alignof
7420	/// Note that the ArgRange is invalid if isType is false.
7421	ExprResult ActOnUnaryExprOrTypeTraitExpr(SourceLocation OpLoc,
7422	UnaryExprOrTypeTrait ExprKind,
7423	bool IsType, void *TyOrEx,
7424	SourceRange ArgRange);
7425
7426	/// Check for operands with placeholder types and complain if found.
7427	/// Returns ExprError() if there was an error and no recovery was possible.
7428	ExprResult CheckPlaceholderExpr(Expr *E);
7429	bool CheckVecStepExpr(Expr *E);
7430
7431	/// Check the constraints on expression operands to unary type expression
7432	/// and type traits.
7433	///
7434	/// Completes any types necessary and validates the constraints on the operand
7435	/// expression. The logic mostly mirrors the type-based overload, but may
7436	/// modify the expression as it completes the type for that expression through
7437	/// template instantiation, etc.
7438	bool CheckUnaryExprOrTypeTraitOperand(Expr *E, UnaryExprOrTypeTrait ExprKind);
7439
7440	/// Check the constraints on operands to unary expression and type
7441	/// traits.
7442	///
7443	/// This will complete any types necessary, and validate the various
7444	/// constraints on those operands.
7445	///
7446	/// The UsualUnaryConversions() function is not* called by this routine.*
7447	/// C99 6.3.2.1p[2-4] all state:
7448	/// Except when it is the operand of the sizeof operator ...
7449	///
7450	/// C++ [expr.sizeof]p4
7451	/// The lvalue-to-rvalue, array-to-pointer, and function-to-pointer
7452	/// standard conversions are not applied to the operand of sizeof.
7453	///
7454	/// This policy is followed for all of the unary trait expressions.
7455	bool CheckUnaryExprOrTypeTraitOperand(QualType ExprType, SourceLocation OpLoc,
7456	SourceRange ExprRange,
7457	UnaryExprOrTypeTrait ExprKind,
7458	StringRef KWName);
7459
7460	ExprResult ActOnPostfixUnaryOp(Scope *S, SourceLocation OpLoc,
7461	tok::TokenKind Kind, Expr *Input);
7462
7463	ExprResult ActOnArraySubscriptExpr(Scope S, Expr Base, SourceLocation LLoc,
7464	MultiExprArg ArgExprs,
7465	SourceLocation RLoc);
7466	ExprResult CreateBuiltinArraySubscriptExpr(Expr *Base, SourceLocation LLoc,
7467	Expr *Idx, SourceLocation RLoc);
7468
7469	ExprResult CreateBuiltinMatrixSingleSubscriptExpr(Expr Base, Expr RowIdx,
7470	SourceLocation RBLoc);
7471
7472	ExprResult CreateBuiltinMatrixSubscriptExpr(Expr Base, Expr RowIdx,
7473	Expr *ColumnIdx,
7474	SourceLocation RBLoc);
7475
7476	/// ConvertArgumentsForCall - Converts the arguments specified in
7477	/// Args/NumArgs to the parameter types of the function FDecl with
7478	/// function prototype Proto. Call is the call expression itself, and
7479	/// Fn is the function expression. For a C++ member function, this
7480	/// routine does not attempt to convert the object argument. Returns
7481	/// true if the call is ill-formed.
7482	bool ConvertArgumentsForCall(CallExpr Call, Expr Fn, FunctionDecl *FDecl,
7483	const FunctionProtoType *Proto,
7484	ArrayRef<Expr *> Args, SourceLocation RParenLoc,
7485	bool ExecConfig = false);
7486
7487	/// CheckStaticArrayArgument - If the given argument corresponds to a static
7488	/// array parameter, check that it is non-null, and that if it is formed by
7489	/// array-to-pointer decay, the underlying array is sufficiently large.
7490	///
7491	/// C99 6.7.5.3p7: If the keyword static also appears within the [ and ] of
7492	/// the array type derivation, then for each call to the function, the value
7493	/// of the corresponding actual argument shall provide access to the first
7494	/// element of an array with at least as many elements as specified by the
7495	/// size expression.
7496	void CheckStaticArrayArgument(SourceLocation CallLoc, ParmVarDecl *Param,
7497	const Expr *ArgExpr);
7498
7499	/// ActOnCallExpr - Handle a call to Fn with the specified array of arguments.
7500	/// This provides the location of the left/right parens and a list of comma
7501	/// locations.
7502	ExprResult ActOnCallExpr(Scope S, Expr Fn, SourceLocation LParenLoc,
7503	MultiExprArg ArgExprs, SourceLocation RParenLoc,
7504	Expr ExecConfig = nullptr*);
7505
7506	/// BuildCallExpr - Handle a call to Fn with the specified array of arguments.
7507	/// This provides the location of the left/right parens and a list of comma
7508	/// locations.
7509	ExprResult BuildCallExpr(Scope S, Expr Fn, SourceLocation LParenLoc,
7510	MultiExprArg ArgExprs, SourceLocation RParenLoc,
7511	Expr ExecConfig = nullptr*,
7512	bool IsExecConfig = false,
7513	bool AllowRecovery = false);
7514
7515	/// BuildBuiltinCallExpr - Create a call to a builtin function specified by Id
7516	// with the specified CallArgs
7517	Expr *BuildBuiltinCallExpr(SourceLocation Loc, Builtin::ID Id,
7518	MultiExprArg CallArgs);
7519
7520	using ADLCallKind = CallExpr::ADLCallKind;
7521
7522	/// BuildResolvedCallExpr - Build a call to a resolved expression,
7523	/// i.e. an expression not of \p OverloadTy. The expression should
7524	/// unary-convert to an expression of function-pointer or
7525	/// block-pointer type.
7526	///
7527	/// \param NDecl the declaration being called, if available
7528	ExprResult
7529	BuildResolvedCallExpr(Expr Fn, NamedDecl NDecl, SourceLocation LParenLoc,
7530	ArrayRef<Expr *> Arg, SourceLocation RParenLoc,
7531	Expr Config = nullptr, bool* IsExecConfig = false,
7532	ADLCallKind UsesADL = ADLCallKind::NotADL);
7533
7534	ExprResult ActOnCastExpr(Scope *S, SourceLocation LParenLoc, Declarator &D,
7535	ParsedType &Ty, SourceLocation RParenLoc,
7536	Expr *CastExpr);
7537
7538	/// Prepares for a scalar cast, performing all the necessary stages
7539	/// except the final cast and returning the kind required.
7540	CastKind PrepareScalarCast(ExprResult &src, QualType destType);
7541
7542	/// Build an altivec or OpenCL literal.
7543	ExprResult BuildVectorLiteral(SourceLocation LParenLoc,
7544	SourceLocation RParenLoc, Expr *E,
7545	TypeSourceInfo *TInfo);
7546
7547	/// This is not an AltiVec-style cast or or C++ direct-initialization, so turn
7548	/// the ParenListExpr into a sequence of comma binary operators.
7549	ExprResult MaybeConvertParenListExprToParenExpr(Scope S, Expr ME);
7550
7551	ExprResult ActOnCompoundLiteral(SourceLocation LParenLoc, ParsedType Ty,
7552	SourceLocation RParenLoc, Expr *InitExpr);
7553
7554	ExprResult BuildCompoundLiteralExpr(SourceLocation LParenLoc,
7555	TypeSourceInfo *TInfo,
7556	SourceLocation RParenLoc,
7557	Expr *LiteralExpr);
7558
7559	ExprResult ActOnInitList(SourceLocation LBraceLoc, MultiExprArg InitArgList,
7560	SourceLocation RBraceLoc);
7561
7562	ExprResult BuildInitList(SourceLocation LBraceLoc, MultiExprArg InitArgList,
7563	SourceLocation RBraceLoc);
7564
7565	/// Binary Operators. 'Tok' is the token for the operator.
7566	ExprResult ActOnBinOp(Scope *S, SourceLocation TokLoc, tok::TokenKind Kind,
7567	Expr LHSExpr, Expr RHSExpr);
7568	ExprResult BuildBinOp(Scope *S, SourceLocation OpLoc, BinaryOperatorKind Opc,
7569	Expr LHSExpr, Expr RHSExpr,
7570	bool ForFoldExpression = false);
7571
7572	/// CreateBuiltinBinOp - Creates a new built-in binary operation with
7573	/// operator @p Opc at location @c TokLoc. This routine only supports
7574	/// built-in operations; ActOnBinOp handles overloaded operators.
7575	ExprResult CreateBuiltinBinOp(SourceLocation OpLoc, BinaryOperatorKind Opc,
7576	Expr LHSExpr, Expr RHSExpr,
7577	bool ForFoldExpression = false);
7578	void LookupBinOp(Scope *S, SourceLocation OpLoc, BinaryOperatorKind Opc,
7579	UnresolvedSetImpl &Functions);
7580
7581	/// Look for instances where it is likely the comma operator is confused with
7582	/// another operator. There is an explicit list of acceptable expressions for
7583	/// the left hand side of the comma operator, otherwise emit a warning.
7584	void DiagnoseCommaOperator(const Expr *LHS, SourceLocation Loc);
7585
7586	/// ActOnConditionalOp - Parse a ?: operation. Note that 'LHS' may be null
7587	/// in the case of a the GNU conditional expr extension.
7588	ExprResult ActOnConditionalOp(SourceLocation QuestionLoc,
7589	SourceLocation ColonLoc, Expr *CondExpr,
7590	Expr LHSExpr, Expr RHSExpr);
7591
7592	/// ActOnAddrLabel - Parse the GNU address of label extension: "&&foo".
7593	ExprResult ActOnAddrLabel(SourceLocation OpLoc, SourceLocation LabLoc,
7594	LabelDecl *TheDecl);
7595
7596	void ActOnStartStmtExpr();
7597	ExprResult ActOnStmtExpr(Scope S, SourceLocation LPLoc, Stmt SubStmt,
7598	SourceLocation RPLoc);
7599	ExprResult BuildStmtExpr(SourceLocation LPLoc, Stmt *SubStmt,
7600	SourceLocation RPLoc, unsigned TemplateDepth);
7601	// Handle the final expression in a statement expression.
7602	ExprResult ActOnStmtExprResult(ExprResult E);
7603	void ActOnStmtExprError();
7604
7605	// __builtin_offsetof(type, identifier(.identifier\|[expr]))*
7606	struct OffsetOfComponent {
7607	SourceLocation LocStart, LocEnd;
7608	bool isBrackets; // true if [expr], false if .ident
7609	union {
7610	IdentifierInfo *IdentInfo;
7611	Expr *E;
7612	} U;
7613	};
7614
7615	/// __builtin_offsetof(type, a.b[123][456].c)
7616	ExprResult BuildBuiltinOffsetOf(SourceLocation BuiltinLoc,
7617	TypeSourceInfo *TInfo,
7618	ArrayRef<OffsetOfComponent> Components,
7619	SourceLocation RParenLoc);
7620	ExprResult ActOnBuiltinOffsetOf(Scope *S, SourceLocation BuiltinLoc,
7621	SourceLocation TypeLoc,
7622	ParsedType ParsedArgTy,
7623	ArrayRef<OffsetOfComponent> Components,
7624	SourceLocation RParenLoc);
7625
7626	// __builtin_choose_expr(constExpr, expr1, expr2)
7627	ExprResult ActOnChooseExpr(SourceLocation BuiltinLoc, Expr *CondExpr,
7628	Expr LHSExpr, Expr RHSExpr,
7629	SourceLocation RPLoc);
7630
7631	// __builtin_va_arg(expr, type)
7632	ExprResult ActOnVAArg(SourceLocation BuiltinLoc, Expr *E, ParsedType Ty,
7633	SourceLocation RPLoc);
7634	ExprResult BuildVAArgExpr(SourceLocation BuiltinLoc, Expr *E,
7635	TypeSourceInfo *TInfo, SourceLocation RPLoc);
7636
7637	// __builtin_LINE(), __builtin_FUNCTION(), __builtin_FUNCSIG(),
7638	// __builtin_FILE(), __builtin_COLUMN(), __builtin_source_location()
7639	ExprResult ActOnSourceLocExpr(SourceLocIdentKind Kind,
7640	SourceLocation BuiltinLoc,
7641	SourceLocation RPLoc);
7642
7643	// #embed
7644	ExprResult ActOnEmbedExpr(SourceLocation EmbedKeywordLoc,
7645	StringLiteral *BinaryData, StringRef FileName);
7646
7647	// Build a potentially resolved SourceLocExpr.
7648	ExprResult BuildSourceLocExpr(SourceLocIdentKind Kind, QualType ResultTy,
7649	SourceLocation BuiltinLoc, SourceLocation RPLoc,
7650	DeclContext *ParentContext);
7651
7652	// __null
7653	ExprResult ActOnGNUNullExpr(SourceLocation TokenLoc);
7654
7655	bool CheckCaseExpression(Expr *E);
7656
7657	//===------------------------- "Block" Extension ------------------------===//
7658
7659	/// ActOnBlockStart - This callback is invoked when a block literal is
7660	/// started.
7661	void ActOnBlockStart(SourceLocation CaretLoc, Scope *CurScope);
7662
7663	/// ActOnBlockArguments - This callback allows processing of block arguments.
7664	/// If there are no arguments, this is still invoked.
7665	void ActOnBlockArguments(SourceLocation CaretLoc, Declarator &ParamInfo,
7666	Scope *CurScope);
7667
7668	/// ActOnBlockError - If there is an error parsing a block, this callback
7669	/// is invoked to pop the information about the block from the action impl.
7670	void ActOnBlockError(SourceLocation CaretLoc, Scope *CurScope);
7671
7672	/// ActOnBlockStmtExpr - This is called when the body of a block statement
7673	/// literal was successfully completed. ^(int x){...}
7674	ExprResult ActOnBlockStmtExpr(SourceLocation CaretLoc, Stmt *Body,
7675	Scope *CurScope);
7676
7677	//===---------------------------- Clang Extensions ----------------------===//
7678
7679	/// ActOnConvertVectorExpr - create a new convert-vector expression from the
7680	/// provided arguments.
7681	///
7682	/// __builtin_convertvector( value, dst type )
7683	///
7684	ExprResult ActOnConvertVectorExpr(Expr *E, ParsedType ParsedDestTy,
7685	SourceLocation BuiltinLoc,
7686	SourceLocation RParenLoc);
7687
7688	//===---------------------------- OpenCL Features -----------------------===//
7689
7690	/// Parse a __builtin_astype expression.
7691	///
7692	/// __builtin_astype( value, dst type )
7693	///
7694	ExprResult ActOnAsTypeExpr(Expr *E, ParsedType ParsedDestTy,
7695	SourceLocation BuiltinLoc,
7696	SourceLocation RParenLoc);
7697
7698	/// Create a new AsTypeExpr node (bitcast) from the arguments.
7699	ExprResult BuildAsTypeExpr(Expr *E, QualType DestTy,
7700	SourceLocation BuiltinLoc,
7701	SourceLocation RParenLoc);
7702
7703	/// Attempts to produce a RecoveryExpr after some AST node cannot be created.
7704	ExprResult CreateRecoveryExpr(SourceLocation Begin, SourceLocation End,
7705	ArrayRef<Expr *> SubExprs,
7706	QualType T = QualType ());
7707
7708	/// Cast a base object to a member's actual type.
7709	///
7710	/// There are two relevant checks:
7711	///
7712	/// C++ [class.access.base]p7:
7713	///
7714	/// If a class member access operator [...] is used to access a non-static
7715	/// data member or non-static member function, the reference is ill-formed
7716	/// if the left operand [...] cannot be implicitly converted to a pointer to
7717	/// the naming class of the right operand.
7718	///
7719	/// C++ [expr.ref]p7:
7720	///
7721	/// If E2 is a non-static data member or a non-static member function, the
7722	/// program is ill-formed if the class of which E2 is directly a member is
7723	/// an ambiguous base (11.8) of the naming class (11.9.3) of E2.
7724	///
7725	/// Note that the latter check does not consider access; the access of the
7726	/// "real" base class is checked as appropriate when checking the access of
7727	/// the member name.
7728	ExprResult PerformObjectMemberConversion(Expr *From,
7729	NestedNameSpecifier Qualifier,
7730	NamedDecl *FoundDecl,
7731	NamedDecl *Member);
7732
7733	/// CheckCallReturnType - Checks that a call expression's return type is
7734	/// complete. Returns true on failure. The location passed in is the location
7735	/// that best represents the call.
7736	bool CheckCallReturnType(QualType ReturnType, SourceLocation Loc,
7737	CallExpr CE, FunctionDecl FD);
7738
7739	/// Emit a warning for all pending noderef expressions that we recorded.
7740	void WarnOnPendingNoDerefs(ExpressionEvaluationContextRecord &Rec);
7741
7742	ExprResult BuildCXXDefaultInitExpr(SourceLocation Loc, FieldDecl *Field);
7743
7744	/// Instantiate or parse a C++ default argument expression as necessary.
7745	/// Return true on error.
7746	bool CheckCXXDefaultArgExpr(SourceLocation CallLoc, FunctionDecl *FD,
7747	ParmVarDecl Param, Expr Init = nullptr,
7748	bool SkipImmediateInvocations = true);
7749
7750	/// BuildCXXDefaultArgExpr - Creates a CXXDefaultArgExpr, instantiating
7751	/// the default expr if needed.
7752	ExprResult BuildCXXDefaultArgExpr(SourceLocation CallLoc, FunctionDecl *FD,
7753	ParmVarDecl Param, Expr Init = nullptr);
7754
7755	/// Wrap the expression in a ConstantExpr if it is a potential immediate
7756	/// invocation.
7757	ExprResult CheckForImmediateInvocation(ExprResult E, FunctionDecl *Decl);
7758
7759	void MarkExpressionAsImmediateEscalating(Expr *E);
7760
7761	// Check that the SME attributes for PSTATE.ZA and PSTATE.SM are compatible.
7762	bool IsInvalidSMECallConversion(QualType FromType, QualType ToType);
7763
7764	/// Abstract base class used for diagnosing integer constant
7765	/// expression violations.
7766	class VerifyICEDiagnoser {
7767	public:
7768	bool Suppress;
7769
7770	VerifyICEDiagnoser(bool Suppress = false) : Suppress(Suppress) {}
7771
7772	virtual SemaDiagnosticBuilder
7773	diagnoseNotICEType(Sema &S, SourceLocation Loc, QualType T);
7774	virtual SemaDiagnosticBuilder diagnoseNotICE(Sema &S,
7775	SourceLocation Loc) = `0`;
7776	virtual SemaDiagnosticBuilder diagnoseFold(Sema &S, SourceLocation Loc);
7777	virtual ~VerifyICEDiagnoser() {}
7778	};
7779
7780	/// VerifyIntegerConstantExpression - Verifies that an expression is an ICE,
7781	/// and reports the appropriate diagnostics. Returns false on success.
7782	/// Can optionally return the value of the expression.
7783	ExprResult
7784	VerifyIntegerConstantExpression(Expr E, llvm::APSInt Result,
7785	VerifyICEDiagnoser &Diagnoser,
7786	AllowFoldKind CanFold = AllowFoldKind::No);
7787	ExprResult
7788	VerifyIntegerConstantExpression(Expr E, llvm::APSInt Result,
7789	unsigned DiagID,
7790	AllowFoldKind CanFold = AllowFoldKind::No);
7791	ExprResult
7792	VerifyIntegerConstantExpression(Expr E, llvm::APSInt Result = nullptr,
7793	AllowFoldKind CanFold = AllowFoldKind::No);
7794	ExprResult
7795	VerifyIntegerConstantExpression(Expr *E,
7796	AllowFoldKind CanFold = AllowFoldKind::No) {
7797	return VerifyIntegerConstantExpression(E, Result: nullptr, CanFold);
7798	}
7799
7800	/// DiagnoseAssignmentAsCondition - Given that an expression is
7801	/// being used as a boolean condition, warn if it's an assignment.
7802	void DiagnoseAssignmentAsCondition(Expr *E);
7803
7804	/// Redundant parentheses over an equality comparison can indicate
7805	/// that the user intended an assignment used as condition.
7806	void DiagnoseEqualityWithExtraParens(ParenExpr *ParenE);
7807
7808	class FullExprArg {
7809	public:
7810	FullExprArg() : E(nullptr) {}
7811	FullExprArg(Sema &actions) : E(nullptr) {}
7812
7813	ExprResult release() { return E; }
7814
7815	Expr get() const* { return E; }
7816
7817	Expr *operator->() { return E; }
7818
7819	private:
7820	// FIXME: No need to make the entire Sema class a friend when it's just
7821	// Sema::MakeFullExpr that needs access to the constructor below.
7822	friend class Sema;
7823
7824	explicit FullExprArg(Expr *expr) : E(expr) {}
7825
7826	Expr *E;
7827	};
7828
7829	FullExprArg MakeFullExpr(Expr *Arg) {
7830	return MakeFullExpr(Arg, CC: Arg ? Arg->getExprLoc() : SourceLocation ());
7831	}
7832	FullExprArg MakeFullExpr(Expr *Arg, SourceLocation CC) {
7833	return FullExprArg (
7834	ActOnFinishFullExpr(Expr: Arg, CC, /DiscardedValue/ DiscardedValue: false).get());
7835	}
7836	FullExprArg MakeFullDiscardedValueExpr(Expr *Arg) {
7837	ExprResult FE =
7838	ActOnFinishFullExpr(Expr: Arg, CC: Arg ? Arg->getExprLoc() : SourceLocation (),
7839	/DiscardedValue/ DiscardedValue: true);
7840	return FullExprArg (FE.get());
7841	}
7842
7843	class ConditionResult {
7844	Decl *ConditionVar;
7845	ExprResult Condition;
7846	bool Invalid;
7847	std::optional<bool> KnownValue;
7848
7849	friend class Sema;
7850	ConditionResult(Sema &S, Decl *ConditionVar, ExprResult Condition,
7851	bool IsConstexpr)
7852	: ConditionVar(ConditionVar), Condition (Condition), Invalid(false) {
7853	if (IsConstexpr && Condition.get()) {
7854	if (std::optional<llvm::APSInt> Val =
7855	Condition.get()->getIntegerConstantExpr(Ctx: S.Context)) {
7856	KnownValue = !!(*Val);
7857	}
7858	}
7859	}
7860	explicit ConditionResult(bool Invalid)
7861	: ConditionVar(nullptr), Condition (Invalid), Invalid(Invalid),
7862	KnownValue (std::nullopt) {}
7863
7864	public:
7865	ConditionResult() : ConditionResult (false) {}
7866	bool isInvalid() const { return Invalid; }
7867	std::pair<VarDecl , Expr > get() const {
7868	return std::make_pair(x: cast_or_null<VarDecl>(Val: ConditionVar),
7869	y: Condition.get());
7870	}
7871	std::optional<bool> getKnownValue() const { return KnownValue; }
7872	};
7873	static ConditionResult ConditionError() { return ConditionResult (true); }
7874
7875	/// CheckBooleanCondition - Diagnose problems involving the use of
7876	/// the given expression as a boolean condition (e.g. in an if
7877	/// statement). Also performs the standard function and array
7878	/// decays, possibly changing the input variable.
7879	///
7880	/// \param Loc - A location associated with the condition, e.g. the
7881	/// 'if' keyword.
7882	/// \return true iff there were any errors
7883	ExprResult CheckBooleanCondition(SourceLocation Loc, Expr *E,
7884	bool IsConstexpr = false);
7885
7886	enum class ConditionKind {
7887	Boolean, ///< A boolean condition, from 'if', 'while', 'for', or 'do'.
7888	ConstexprIf, ///< A constant boolean condition from 'if constexpr'.
7889	Switch ///< An integral condition for a 'switch' statement.
7890	};
7891
7892	ConditionResult ActOnCondition(Scope S, SourceLocation Loc, Expr SubExpr,
7893	ConditionKind CK, bool MissingOK = false);
7894
7895	QualType CheckConditionalOperands( // C99 6.5.15
7896	ExprResult &Cond, ExprResult &LHS, ExprResult &RHS, ExprValueKind &VK,
7897	ExprObjectKind &OK, SourceLocation QuestionLoc);
7898
7899	/// Emit a specialized diagnostic when one expression is a null pointer
7900	/// constant and the other is not a pointer. Returns true if a diagnostic is
7901	/// emitted.
7902	bool DiagnoseConditionalForNull(const Expr LHSExpr, const* Expr *RHSExpr,
7903	SourceLocation QuestionLoc);
7904
7905	/// type checking for vector binary operators.
7906	QualType CheckVectorOperands(ExprResult &LHS, ExprResult &RHS,
7907	SourceLocation Loc, bool IsCompAssign,
7908	bool AllowBothBool, bool AllowBoolConversion,
7909	bool AllowBoolOperation, bool ReportInvalid);
7910
7911	/// Return a signed ext_vector_type that is of identical size and number of
7912	/// elements. For floating point vectors, return an integer type of identical
7913	/// size and number of elements. In the non ext_vector_type case, search from
7914	/// the largest type to the smallest type to avoid cases where long long ==
7915	/// long, where long gets picked over long long.
7916	QualType GetSignedVectorType(QualType V);
7917	QualType GetSignedSizelessVectorType(QualType V);
7918
7919	/// CheckVectorCompareOperands - vector comparisons are a clang extension that
7920	/// operates on extended vector types. Instead of producing an IntTy result,
7921	/// like a scalar comparison, a vector comparison produces a vector of integer
7922	/// types.
7923	QualType CheckVectorCompareOperands(ExprResult &LHS, ExprResult &RHS,
7924	SourceLocation Loc,
7925	BinaryOperatorKind Opc);
7926	QualType CheckSizelessVectorCompareOperands(ExprResult &LHS, ExprResult &RHS,
7927	SourceLocation Loc,
7928	BinaryOperatorKind Opc);
7929	QualType CheckVectorLogicalOperands(ExprResult &LHS, ExprResult &RHS,
7930	SourceLocation Loc,
7931	BinaryOperatorKind Opc);
7932	QualType CheckMatrixLogicalOperands(ExprResult &LHS, ExprResult &RHS,
7933	SourceLocation Loc,
7934	BinaryOperatorKind Opc);
7935	// type checking for sizeless vector binary operators.
7936	QualType CheckSizelessVectorOperands(ExprResult &LHS, ExprResult &RHS,
7937	SourceLocation Loc, bool IsCompAssign,
7938	ArithConvKind OperationKind);
7939
7940	/// Type checking for matrix binary operators.
7941	QualType CheckMatrixElementwiseOperands(ExprResult &LHS, ExprResult &RHS,
7942	SourceLocation Loc,
7943	bool IsCompAssign);
7944	QualType CheckMatrixMultiplyOperands(ExprResult &LHS, ExprResult &RHS,
7945	SourceLocation Loc, bool IsCompAssign);
7946
7947	/// Are the two types SVE-bitcast-compatible types? I.e. is bitcasting from
7948	/// the first SVE type (e.g. an SVE VLAT) to the second type (e.g. an SVE
7949	/// VLST) allowed?
7950	///
7951	/// This will also return false if the two given types do not make sense from
7952	/// the perspective of SVE bitcasts.
7953	bool isValidSveBitcast(QualType srcType, QualType destType);
7954
7955	/// Are the two types matrix types and do they have the same dimensions i.e.
7956	/// do they have the same number of rows and the same number of columns?
7957	bool areMatrixTypesOfTheSameDimension(QualType srcTy, QualType destTy);
7958
7959	bool areVectorTypesSameSize(QualType srcType, QualType destType);
7960
7961	/// Are the two types lax-compatible vector types? That is, given
7962	/// that one of them is a vector, do they have equal storage sizes,
7963	/// where the storage size is the number of elements times the element
7964	/// size?
7965	///
7966	/// This will also return false if either of the types is neither a
7967	/// vector nor a real type.
7968	bool areLaxCompatibleVectorTypes(QualType srcType, QualType destType);
7969
7970	/// Is this a legal conversion between two types, one of which is
7971	/// known to be a vector type?
7972	bool isLaxVectorConversion(QualType srcType, QualType destType);
7973
7974	// This returns true if at least one of the types is an altivec vector.
7975	bool anyAltivecTypes(QualType srcType, QualType destType);
7976
7977	// type checking C++ declaration initializers (C++ [dcl.init]).
7978
7979	/// Check a cast of an unknown-any type. We intentionally only
7980	/// trigger this for C-style casts.
7981	ExprResult checkUnknownAnyCast(SourceRange TypeRange, QualType CastType,
7982	Expr *CastExpr, CastKind &CastKind,
7983	ExprValueKind &VK, CXXCastPath &Path);
7984
7985	/// Force an expression with unknown-type to an expression of the
7986	/// given type.
7987	ExprResult forceUnknownAnyToType(Expr *E, QualType ToType);
7988
7989	/// Type-check an expression that's being passed to an
7990	/// __unknown_anytype parameter.
7991	ExprResult checkUnknownAnyArg(SourceLocation callLoc, Expr *result,
7992	QualType &paramType);
7993
7994	// CheckMatrixCast - Check type constraints for matrix casts.
7995	// We allow casting between matrixes of the same dimensions i.e. when they
7996	// have the same number of rows and column. Returns true if the cast is
7997	// invalid.
7998	bool CheckMatrixCast(SourceRange R, QualType DestTy, QualType SrcTy,
7999	CastKind &Kind);
8000
8001	// CheckVectorCast - check type constraints for vectors.
8002	// Since vectors are an extension, there are no C standard reference for this.
8003	// We allow casting between vectors and integer datatypes of the same size.
8004	// returns true if the cast is invalid
8005	bool CheckVectorCast(SourceRange R, QualType VectorTy, QualType Ty,
8006	CastKind &Kind);
8007
8008	/// Prepare `SplattedExpr` for a vector splat operation, adding
8009	/// implicit casts if necessary.
8010	ExprResult prepareVectorSplat(QualType VectorTy, Expr *SplattedExpr);
8011
8012	/// Prepare `SplattedExpr` for a matrix splat operation, adding
8013	/// implicit casts if necessary.
8014	ExprResult prepareMatrixSplat(QualType MatrixTy, Expr *SplattedExpr);
8015
8016	// CheckExtVectorCast - check type constraints for extended vectors.
8017	// Since vectors are an extension, there are no C standard reference for this.
8018	// We allow casting between vectors and integer datatypes of the same size,
8019	// or vectors and the element type of that vector.
8020	// returns the cast expr
8021	ExprResult CheckExtVectorCast(SourceRange R, QualType DestTy, Expr *CastExpr,
8022	CastKind &Kind);
8023
8024	QualType PreferredConditionType(ConditionKind K) const {
8025	return K == ConditionKind::Switch ? Context.IntTy : Context.BoolTy;
8026	}
8027
8028	// UsualUnaryConversions - promotes integers (C99 6.3.1.1p2), converts
8029	// functions and arrays to their respective pointers (C99 6.3.2.1), and
8030	// promotes floating-piont types according to the language semantics.
8031	ExprResult UsualUnaryConversions(Expr *E);
8032
8033	// UsualUnaryFPConversions - promotes floating-point types according to the
8034	// current language semantics.
8035	ExprResult UsualUnaryFPConversions(Expr *E);
8036
8037	/// CallExprUnaryConversions - a special case of an unary conversion
8038	/// performed on a function designator of a call expression.
8039	ExprResult CallExprUnaryConversions(Expr *E);
8040
8041	// DefaultFunctionArrayConversion - converts functions and arrays
8042	// to their respective pointers (C99 6.3.2.1).
8043	ExprResult DefaultFunctionArrayConversion(Expr E, bool* Diagnose = true);
8044
8045	// DefaultFunctionArrayLvalueConversion - converts functions and
8046	// arrays to their respective pointers and performs the
8047	// lvalue-to-rvalue conversion.
8048	ExprResult DefaultFunctionArrayLvalueConversion(Expr *E,
8049	bool Diagnose = true);
8050
8051	// DefaultLvalueConversion - performs lvalue-to-rvalue conversion on
8052	// the operand. This function is a no-op if the operand has a function type
8053	// or an array type.
8054	ExprResult DefaultLvalueConversion(Expr *E);
8055
8056	// DefaultArgumentPromotion (C99 6.5.2.2p6). Used for function calls that
8057	// do not have a prototype. Integer promotions are performed on each
8058	// argument, and arguments that have type float are promoted to double.
8059	ExprResult DefaultArgumentPromotion(Expr *E);
8060
8061	VariadicCallType getVariadicCallType(FunctionDecl *FDecl,
8062	const FunctionProtoType *Proto,
8063	Expr *Fn);
8064
8065	/// Determine the degree of POD-ness for an expression.
8066	/// Incomplete types are considered POD, since this check can be performed
8067	/// when we're in an unevaluated context.
8068	VarArgKind isValidVarArgType(const QualType &Ty);
8069
8070	/// Check to see if the given expression is a valid argument to a variadic
8071	/// function, issuing a diagnostic if not.
8072	void checkVariadicArgument(const Expr *E, VariadicCallType CT);
8073
8074	/// GatherArgumentsForCall - Collector argument expressions for various
8075	/// form of call prototypes.
8076	bool GatherArgumentsForCall(
8077	SourceLocation CallLoc, FunctionDecl *FDecl,
8078	const FunctionProtoType Proto, unsigned* FirstParam,
8079	ArrayRef<Expr > Args, SmallVectorImpl<Expr > &AllArgs,
8080	VariadicCallType CallType = VariadicCallType::DoesNotApply,
8081	bool AllowExplicit = false, bool IsListInitialization = false);
8082
8083	// DefaultVariadicArgumentPromotion - Like DefaultArgumentPromotion, but
8084	// will create a runtime trap if the resulting type is not a POD type.
8085	ExprResult DefaultVariadicArgumentPromotion(Expr *E, VariadicCallType CT,
8086	FunctionDecl *FDecl);
8087
8088	// Check that the usual arithmetic conversions can be performed on this pair
8089	// of expressions that might be of enumeration type.
8090	void checkEnumArithmeticConversions(Expr LHS, Expr RHS, SourceLocation Loc,
8091	ArithConvKind ACK);
8092
8093	// UsualArithmeticConversions - performs the UsualUnaryConversions on it's
8094	// operands and then handles various conversions that are common to binary
8095	// operators (C99 6.3.1.8). If both operands aren't arithmetic, this
8096	// routine returns the first non-arithmetic type found. The client is
8097	// responsible for emitting appropriate error diagnostics.
8098	QualType UsualArithmeticConversions(ExprResult &LHS, ExprResult &RHS,
8099	SourceLocation Loc, ArithConvKind ACK);
8100
8101	bool IsAssignConvertCompatible(AssignConvertType ConvTy) {
8102	switch (ConvTy) {
8103	default:
8104	return false;
8105	case AssignConvertType::Compatible:
8106	case AssignConvertType::CompatiblePointerDiscardsQualifiers:
8107	case AssignConvertType::CompatibleVoidPtrToNonVoidPtr:
8108	return true;
8109	}
8110	llvm_unreachable("impossible");
8111	}
8112
8113	/// DiagnoseAssignmentResult - Emit a diagnostic, if required, for the
8114	/// assignment conversion type specified by ConvTy. This returns true if the
8115	/// conversion was invalid or false if the conversion was accepted.
8116	bool DiagnoseAssignmentResult(AssignConvertType ConvTy, SourceLocation Loc,
8117	QualType DstType, QualType SrcType,
8118	Expr *SrcExpr, AssignmentAction Action,
8119	bool Complained = nullptr*);
8120
8121	/// CheckAssignmentConstraints - Perform type checking for assignment,
8122	/// argument passing, variable initialization, and function return values.
8123	/// C99 6.5.16.
8124	AssignConvertType CheckAssignmentConstraints(SourceLocation Loc,
8125	QualType LHSType,
8126	QualType RHSType);
8127
8128	/// Check assignment constraints and optionally prepare for a conversion of
8129	/// the RHS to the LHS type. The conversion is prepared for if ConvertRHS
8130	/// is true.
8131	AssignConvertType CheckAssignmentConstraints(QualType LHSType,
8132	ExprResult &RHS, CastKind &Kind,
8133	bool ConvertRHS = true);
8134
8135	/// Check assignment constraints for an assignment of RHS to LHSType.
8136	///
8137	/// \param LHSType The destination type for the assignment.
8138	/// \param RHS The source expression for the assignment.
8139	/// \param Diagnose If \c true, diagnostics may be produced when checking
8140	/// for assignability. If a diagnostic is produced, \p RHS will be
8141	/// set to ExprError(). Note that this function may still return
8142	/// without producing a diagnostic, even for an invalid assignment.
8143	/// \param DiagnoseCFAudited If \c true, the target is a function parameter
8144	/// in an audited Core Foundation API and does not need to be checked
8145	/// for ARC retain issues.
8146	/// \param ConvertRHS If \c true, \p RHS will be updated to model the
8147	/// conversions necessary to perform the assignment. If \c false,
8148	/// \p Diagnose must also be \c false.
8149	AssignConvertType CheckSingleAssignmentConstraints(
8150	QualType LHSType, ExprResult &RHS, bool Diagnose = true,
8151	bool DiagnoseCFAudited = false, bool ConvertRHS = true);
8152
8153	// If the lhs type is a transparent union, check whether we
8154	// can initialize the transparent union with the given expression.
8155	AssignConvertType CheckTransparentUnionArgumentConstraints(QualType ArgType,
8156	ExprResult &RHS);
8157
8158	/// the following "Check" methods will return a valid/converted QualType
8159	/// or a null QualType (indicating an error diagnostic was issued).
8160
8161	/// type checking binary operators (subroutines of CreateBuiltinBinOp).
8162	QualType InvalidOperands(SourceLocation Loc, ExprResult &LHS,
8163	ExprResult &RHS);
8164
8165	/// Diagnose cases where a scalar was implicitly converted to a vector and
8166	/// diagnose the underlying types. Otherwise, diagnose the error
8167	/// as invalid vector logical operands for non-C++ cases.
8168	QualType InvalidLogicalVectorOperands(SourceLocation Loc, ExprResult &LHS,
8169	ExprResult &RHS);
8170
8171	QualType CheckMultiplyDivideOperands( // C99 6.5.5
8172	ExprResult &LHS, ExprResult &RHS, SourceLocation Loc,
8173	BinaryOperatorKind Opc);
8174	QualType CheckRemainderOperands( // C99 6.5.5
8175	ExprResult &LHS, ExprResult &RHS, SourceLocation Loc,
8176	bool IsCompAssign = false);
8177	QualType CheckAdditionOperands( // C99 6.5.6
8178	ExprResult &LHS, ExprResult &RHS, SourceLocation Loc,
8179	BinaryOperatorKind Opc, QualType CompLHSTy = nullptr*);
8180	QualType CheckSubtractionOperands( // C99 6.5.6
8181	ExprResult &LHS, ExprResult &RHS, SourceLocation Loc,
8182	BinaryOperatorKind Opc, QualType CompLHSTy = nullptr*);
8183	QualType CheckShiftOperands( // C99 6.5.7
8184	ExprResult &LHS, ExprResult &RHS, SourceLocation Loc,
8185	BinaryOperatorKind Opc, bool IsCompAssign = false);
8186	void CheckPtrComparisonWithNullChar(ExprResult &E, ExprResult &NullE);
8187	QualType CheckCompareOperands( // C99 6.5.8/9
8188	ExprResult &LHS, ExprResult &RHS, SourceLocation Loc,
8189	BinaryOperatorKind Opc);
8190	QualType CheckBitwiseOperands( // C99 6.5.[10...12]
8191	ExprResult &LHS, ExprResult &RHS, SourceLocation Loc,
8192	BinaryOperatorKind Opc);
8193	QualType CheckLogicalOperands( // C99 6.5.[13,14]
8194	ExprResult &LHS, ExprResult &RHS, SourceLocation Loc,
8195	BinaryOperatorKind Opc);
8196	// CheckAssignmentOperands is used for both simple and compound assignment.
8197	// For simple assignment, pass both expressions and a null converted type.
8198	// For compound assignment, pass both expressions and the converted type.
8199	QualType CheckAssignmentOperands( // C99 6.5.16.[1,2]
8200	Expr *LHSExpr, ExprResult &RHS, SourceLocation Loc, QualType CompoundType,
8201	BinaryOperatorKind Opc);
8202
8203	/// To be used for checking whether the arguments being passed to
8204	/// function exceeds the number of parameters expected for it.
8205	static bool TooManyArguments(size_t NumParams, size_t NumArgs,
8206	bool PartialOverloading = false) {
8207	// We check whether we're just after a comma in code-completion.
8208	if (NumArgs > `0` && PartialOverloading)
8209	return NumArgs + `1` > NumParams; // If so, we view as an extra argument.
8210	return NumArgs > NumParams;
8211	}
8212
8213	/// Whether the AST is currently being rebuilt to correct immediate
8214	/// invocations. Immediate invocation candidates and references to consteval
8215	/// functions aren't tracked when this is set.
8216	bool RebuildingImmediateInvocation = false;
8217
8218	bool isAlwaysConstantEvaluatedContext() const {
8219	const ExpressionEvaluationContextRecord &Ctx = currentEvaluationContext();
8220	return (Ctx.isConstantEvaluated() \|\| isConstantEvaluatedOverride) &&
8221	!Ctx.InConditionallyConstantEvaluateContext;
8222	}
8223
8224	/// Determines whether we are currently in a context that
8225	/// is not evaluated as per C++ [expr] p5.
8226	bool isUnevaluatedContext() const {
8227	return currentEvaluationContext().isUnevaluated();
8228	}
8229
8230	bool isImmediateFunctionContext() const {
8231	return currentEvaluationContext().isImmediateFunctionContext();
8232	}
8233
8234	bool isInLifetimeExtendingContext() const {
8235	return currentEvaluationContext().InLifetimeExtendingContext;
8236	}
8237
8238	bool needsRebuildOfDefaultArgOrInit() const {
8239	return currentEvaluationContext().RebuildDefaultArgOrDefaultInit;
8240	}
8241
8242	bool isCheckingDefaultArgumentOrInitializer() const {
8243	const ExpressionEvaluationContextRecord &Ctx = currentEvaluationContext();
8244	return (Ctx.Context ==
8245	ExpressionEvaluationContext::PotentiallyEvaluatedIfUsed) \|\|
8246	Ctx.IsCurrentlyCheckingDefaultArgumentOrInitializer;
8247	}
8248
8249	std::optional<ExpressionEvaluationContextRecord::InitializationContext>
8250	InnermostDeclarationWithDelayedImmediateInvocations() const {
8251	assert(!ExprEvalContexts.empty() &&
8252	"Must be in an expression evaluation context");
8253	for (const auto &Ctx : llvm::reverse(C: ExprEvalContexts)) {
8254	if (Ctx.Context == ExpressionEvaluationContext::PotentiallyEvaluated &&
8255	Ctx.DelayedDefaultInitializationContext)
8256	return Ctx.DelayedDefaultInitializationContext;
8257	if (Ctx.isConstantEvaluated() \|\| Ctx.isImmediateFunctionContext() \|\|
8258	Ctx.isUnevaluated())
8259	break;
8260	}
8261	return std::nullopt;
8262	}
8263
8264	std::optional<ExpressionEvaluationContextRecord::InitializationContext>
8265	OutermostDeclarationWithDelayedImmediateInvocations() const {
8266	assert(!ExprEvalContexts.empty() &&
8267	"Must be in an expression evaluation context");
8268	std::optional<ExpressionEvaluationContextRecord::InitializationContext> Res;
8269	for (auto &Ctx : llvm::reverse(C: ExprEvalContexts)) {
8270	if (Ctx.Context == ExpressionEvaluationContext::PotentiallyEvaluated &&
8271	!Ctx.DelayedDefaultInitializationContext && Res)
8272	break;
8273	if (Ctx.isConstantEvaluated() \|\| Ctx.isImmediateFunctionContext() \|\|
8274	Ctx.isUnevaluated())
8275	break;
8276	Res = Ctx.DelayedDefaultInitializationContext;
8277	}
8278	return Res;
8279	}
8280
8281	DefaultedComparisonKind getDefaultedComparisonKind(const FunctionDecl *FD) {
8282	return getDefaultedFunctionKind(FD).asComparison();
8283	}
8284
8285	/// Returns a field in a CXXRecordDecl that has the same name as the decl \p
8286	/// SelfAssigned when inside a CXXMethodDecl.
8287	const FieldDecl *
8288	getSelfAssignmentClassMemberCandidate(const ValueDecl *SelfAssigned);
8289
8290	void MaybeSuggestAddingStaticToDecl(const FunctionDecl *D);
8291
8292	template <typename... Ts>
8293	bool RequireCompleteSizedType(SourceLocation Loc, QualType T, unsigned DiagID,
8294	const Ts &...Args) {
8295	SizelessTypeDiagnoser<Ts...> Diagnoser(DiagID, Args...);
8296	return RequireCompleteType(Loc, T, CompleteTypeKind::Normal, Diagnoser);
8297	}
8298
8299	template <typename... Ts>
8300	bool RequireCompleteSizedExprType(Expr E, unsigned* DiagID,
8301	const Ts &...Args) {
8302	SizelessTypeDiagnoser<Ts...> Diagnoser(DiagID, Args...);
8303	return RequireCompleteExprType(E, CompleteTypeKind::Normal, Diagnoser);
8304	}
8305
8306	/// Abstract class used to diagnose incomplete types.
8307	struct TypeDiagnoser {
8308	TypeDiagnoser() {}
8309
8310	virtual void diagnose(Sema &S, SourceLocation Loc, QualType T) = `0`;
8311	virtual ~TypeDiagnoser() {}
8312	};
8313
8314	template <typename... Ts> class BoundTypeDiagnoser : public TypeDiagnoser {
8315	protected:
8316	unsigned DiagID;
8317	std::tuple<const Ts &...> Args;
8318
8319	template <std::size_t... Is>
8320	void emit(const SemaDiagnosticBuilder &DB,
8321	std::index_sequence<Is...>) const {
8322	// Apply all tuple elements to the builder in order.
8323	bool Dummy[] = {false, (DB << getPrintable(std::get<Is>(Args)))...};
8324	(void)Dummy;
8325	}
8326
8327	public:
8328	BoundTypeDiagnoser(unsigned DiagID, const Ts &...Args)
8329	: TypeDiagnoser(), DiagID(DiagID), Args(Args...) {
8330	assert(DiagID != `0` && "no diagnostic for type diagnoser");
8331	}
8332
8333	void diagnose(Sema &S, SourceLocation Loc, QualType T) override {
8334	const SemaDiagnosticBuilder &DB = S.Diag(Loc, DiagID);
8335	emit(DB, std::index_sequence_for<Ts...>());
8336	DB << T;
8337	}
8338	};
8339
8340	/// A derivative of BoundTypeDiagnoser for which the diagnostic's type
8341	/// parameter is preceded by a 0/1 enum that is 1 if the type is sizeless.
8342	/// For example, a diagnostic with no other parameters would generally have
8343	/// the form "...%select{incomplete\|sizeless}0 type %1...".
8344	template <typename... Ts>
8345	class SizelessTypeDiagnoser : public BoundTypeDiagnoser<Ts...> {
8346	public:
8347	SizelessTypeDiagnoser(unsigned DiagID, const Ts &...Args)
8348	: BoundTypeDiagnoser<Ts...>(DiagID, Args...) {}
8349
8350	void diagnose(Sema &S, SourceLocation Loc, QualType T) override {
8351	const SemaDiagnosticBuilder &DB = S.Diag(Loc, this->DiagID);
8352	this->emit(DB, std::index_sequence_for<Ts...>());
8353	DB << T ->isSizelessType() << T;
8354	}
8355	};
8356
8357	/// Check an argument list for placeholders that we won't try to
8358	/// handle later.
8359	bool CheckArgsForPlaceholders(MultiExprArg args);
8360
8361	/// The C++ "std::source_location::__impl" struct, defined in
8362	/// \<source_location>.
8363	RecordDecl *StdSourceLocationImplDecl;
8364
8365	/// A stack of expression evaluation contexts.
8366	SmallVector<ExpressionEvaluationContextRecord, `8`> ExprEvalContexts;
8367
8368	// Set of failed immediate invocations to avoid double diagnosing.
8369	llvm::SmallPtrSet<ConstantExpr *, `4`> FailedImmediateInvocations;
8370
8371	/// List of SourceLocations where 'self' is implicitly retained inside a
8372	/// block.
8373	llvm::SmallVector<std::pair<SourceLocation, const BlockDecl *>, `1`>
8374	ImplicitlyRetainedSelfLocs;
8375
8376	/// Do an explicit extend of the given block pointer if we're in ARC.
8377	void maybeExtendBlockObject(ExprResult &E);
8378
8379	std::vector<std::pair<QualType, unsigned>> ExcessPrecisionNotSatisfied;
8380	SourceLocation LocationOfExcessPrecisionNotSatisfied;
8381	void DiagnosePrecisionLossInComplexDivision();
8382
8383	private:
8384	static BinaryOperatorKind ConvertTokenKindToBinaryOpcode(tok::TokenKind Kind);
8385
8386	/// Methods for marking which expressions involve dereferencing a pointer
8387	/// marked with the 'noderef' attribute. Expressions are checked bottom up as
8388	/// they are parsed, meaning that a noderef pointer may not be accessed. For
8389	/// example, in `&p` where `p` is a noderef pointer, we will first parse the*
8390	/// `p`, but need to check that `address of` is called on it. This requires*
8391	/// keeping a container of all pending expressions and checking if the address
8392	/// of them are eventually taken.
8393	void CheckSubscriptAccessOfNoDeref(const ArraySubscriptExpr *E);
8394	void CheckAddressOfNoDeref(const Expr *E);
8395
8396	///@}
8397
8398	//
8399	//
8400	// -------------------------------------------------------------------------
8401	//
8402	//
8403
8404	/// \name C++ Expressions
8405	/// Implementations are in SemaExprCXX.cpp
8406	///@{
8407
8408	public:
8409	/// The C++ "std::bad_alloc" class, which is defined by the C++
8410	/// standard library.
8411	LazyDeclPtr StdBadAlloc;
8412
8413	/// The C++ "std::align_val_t" enum class, which is defined by the C++
8414	/// standard library.
8415	LazyDeclPtr StdAlignValT;
8416
8417	/// The C++ "type_info" declaration, which is defined in \<typeinfo>.
8418	RecordDecl *CXXTypeInfoDecl;
8419
8420	/// A flag to remember whether the implicit forms of operator new and delete
8421	/// have been declared.
8422	bool GlobalNewDeleteDeclared;
8423
8424	/// Delete-expressions to be analyzed at the end of translation unit
8425	///
8426	/// This list contains class members, and locations of delete-expressions
8427	/// that could not be proven as to whether they mismatch with new-expression
8428	/// used in initializer of the field.
8429	llvm::MapVector<FieldDecl *, DeleteLocs> DeleteExprs;
8430
8431	/// Handle the result of the special case name lookup for inheriting
8432	/// constructor declarations. 'NS::X::X' and 'NS::X<...>::X' are treated as
8433	/// constructor names in member using declarations, even if 'X' is not the
8434	/// name of the corresponding type.
8435	ParsedType getInheritingConstructorName(CXXScopeSpec &SS,
8436	SourceLocation NameLoc,
8437	const IdentifierInfo &Name);
8438
8439	ParsedType getConstructorName(const IdentifierInfo &II,
8440	SourceLocation NameLoc, Scope *S,
8441	CXXScopeSpec &SS, bool EnteringContext);
8442	ParsedType getDestructorName(const IdentifierInfo &II, SourceLocation NameLoc,
8443	Scope *S, CXXScopeSpec &SS,
8444	ParsedType ObjectType, bool EnteringContext);
8445
8446	ParsedType getDestructorTypeForDecltype(const DeclSpec &DS,
8447	ParsedType ObjectType);
8448
8449	/// Build a C++ typeid expression with a type operand.
8450	ExprResult BuildCXXTypeId(QualType TypeInfoType, SourceLocation TypeidLoc,
8451	TypeSourceInfo *Operand, SourceLocation RParenLoc);
8452
8453	/// Build a C++ typeid expression with an expression operand.
8454	ExprResult BuildCXXTypeId(QualType TypeInfoType, SourceLocation TypeidLoc,
8455	Expr *Operand, SourceLocation RParenLoc);
8456
8457	/// ActOnCXXTypeid - Parse typeid( something ).
8458	ExprResult ActOnCXXTypeid(SourceLocation OpLoc, SourceLocation LParenLoc,
8459	bool isType, void *TyOrExpr,
8460	SourceLocation RParenLoc);
8461
8462	/// Build a Microsoft __uuidof expression with a type operand.
8463	ExprResult BuildCXXUuidof(QualType TypeInfoType, SourceLocation TypeidLoc,
8464	TypeSourceInfo *Operand, SourceLocation RParenLoc);
8465
8466	/// Build a Microsoft __uuidof expression with an expression operand.
8467	ExprResult BuildCXXUuidof(QualType TypeInfoType, SourceLocation TypeidLoc,
8468	Expr *Operand, SourceLocation RParenLoc);
8469
8470	/// ActOnCXXUuidof - Parse __uuidof( something ).
8471	ExprResult ActOnCXXUuidof(SourceLocation OpLoc, SourceLocation LParenLoc,
8472	bool isType, void *TyOrExpr,
8473	SourceLocation RParenLoc);
8474
8475	//// ActOnCXXThis - Parse 'this' pointer.
8476	ExprResult ActOnCXXThis(SourceLocation Loc);
8477
8478	/// Check whether the type of 'this' is valid in the current context.
8479	bool CheckCXXThisType(SourceLocation Loc, QualType Type);
8480
8481	/// Build a CXXThisExpr and mark it referenced in the current context.
8482	Expr BuildCXXThisExpr(SourceLocation Loc, QualType Type, bool* IsImplicit);
8483	void MarkThisReferenced(CXXThisExpr *This);
8484
8485	/// Try to retrieve the type of the 'this' pointer.
8486	///
8487	/// \returns The type of 'this', if possible. Otherwise, returns a NULL type.
8488	QualType getCurrentThisType();
8489
8490	/// When non-NULL, the C++ 'this' expression is allowed despite the
8491	/// current context not being a non-static member function. In such cases,
8492	/// this provides the type used for 'this'.
8493	QualType CXXThisTypeOverride;
8494
8495	/// RAII object used to temporarily allow the C++ 'this' expression
8496	/// to be used, with the given qualifiers on the current class type.
8497	class CXXThisScopeRAII {
8498	Sema &S;
8499	QualType OldCXXThisTypeOverride;
8500	bool Enabled;
8501
8502	public:
8503	/// Introduce a new scope where 'this' may be allowed (when enabled),
8504	/// using the given declaration (which is either a class template or a
8505	/// class) along with the given qualifiers.
8506	/// along with the qualifiers placed on 'this'.*
8507	CXXThisScopeRAII(Sema &S, Decl *ContextDecl, Qualifiers CXXThisTypeQuals,
8508	bool Enabled = true);
8509
8510	~CXXThisScopeRAII();
8511	CXXThisScopeRAII(const CXXThisScopeRAII &) = delete;
8512	CXXThisScopeRAII &operator=(const CXXThisScopeRAII &) = delete;
8513	};
8514
8515	/// Make sure the value of 'this' is actually available in the current
8516	/// context, if it is a potentially evaluated context.
8517	///
8518	/// \param Loc The location at which the capture of 'this' occurs.
8519	///
8520	/// \param Explicit Whether 'this' is explicitly captured in a lambda
8521	/// capture list.
8522	///
8523	/// \param FunctionScopeIndexToStopAt If non-null, it points to the index
8524	/// of the FunctionScopeInfo stack beyond which we do not attempt to capture.
8525	/// This is useful when enclosing lambdas must speculatively capture
8526	/// 'this' that may or may not be used in certain specializations of
8527	/// a nested generic lambda (depending on whether the name resolves to
8528	/// a non-static member function or a static function).
8529	/// \return returns 'true' if failed, 'false' if success.
8530	bool CheckCXXThisCapture(
8531	SourceLocation Loc, bool Explicit = false, bool BuildAndDiagnose = true,
8532	const unsigned *const FunctionScopeIndexToStopAt = nullptr,
8533	bool ByCopy = false);
8534
8535	/// Determine whether the given type is the type of this that is used*
8536	/// outside of the body of a member function for a type that is currently
8537	/// being defined.
8538	bool isThisOutsideMemberFunctionBody(QualType BaseType);
8539
8540	/// ActOnCXXBoolLiteral - Parse {true,false} literals.
8541	ExprResult ActOnCXXBoolLiteral(SourceLocation OpLoc, tok::TokenKind Kind);
8542
8543	/// ActOnCXXNullPtrLiteral - Parse 'nullptr'.
8544	ExprResult ActOnCXXNullPtrLiteral(SourceLocation Loc);
8545
8546	//// ActOnCXXThrow - Parse throw expressions.
8547	ExprResult ActOnCXXThrow(Scope S, SourceLocation OpLoc, Expr expr);
8548	ExprResult BuildCXXThrow(SourceLocation OpLoc, Expr *Ex,
8549	bool IsThrownVarInScope);
8550
8551	/// CheckCXXThrowOperand - Validate the operand of a throw.
8552	bool CheckCXXThrowOperand(SourceLocation ThrowLoc, QualType ThrowTy, Expr *E);
8553
8554	/// ActOnCXXTypeConstructExpr - Parse construction of a specified type.
8555	/// Can be interpreted either as function-style casting ("int(x)")
8556	/// or class type construction ("ClassType(x,y,z)")
8557	/// or creation of a value-initialized type ("int()").
8558	ExprResult ActOnCXXTypeConstructExpr(ParsedType TypeRep,
8559	SourceLocation LParenOrBraceLoc,
8560	MultiExprArg Exprs,
8561	SourceLocation RParenOrBraceLoc,
8562	bool ListInitialization);
8563
8564	ExprResult BuildCXXTypeConstructExpr(TypeSourceInfo *Type,
8565	SourceLocation LParenLoc,
8566	MultiExprArg Exprs,
8567	SourceLocation RParenLoc,
8568	bool ListInitialization);
8569
8570	/// Parsed a C++ 'new' expression (C++ 5.3.4).
8571	///
8572	/// E.g.:
8573	/// @code new (memory) int[size][4] @endcode
8574	/// or
8575	/// @code ::new Foo(23, "hello") @endcode
8576	///
8577	/// \param StartLoc The first location of the expression.
8578	/// \param UseGlobal True if 'new' was prefixed with '::'.
8579	/// \param PlacementLParen Opening paren of the placement arguments.
8580	/// \param PlacementArgs Placement new arguments.
8581	/// \param PlacementRParen Closing paren of the placement arguments.
8582	/// \param TypeIdParens If the type is in parens, the source range.
8583	/// \param D The type to be allocated, as well as array dimensions.
8584	/// \param Initializer The initializing expression or initializer-list, or
8585	/// null if there is none.
8586	ExprResult ActOnCXXNew(SourceLocation StartLoc, bool UseGlobal,
8587	SourceLocation PlacementLParen,
8588	MultiExprArg PlacementArgs,
8589	SourceLocation PlacementRParen,
8590	SourceRange TypeIdParens, Declarator &D,
8591	Expr *Initializer);
8592	ExprResult
8593	BuildCXXNew(SourceRange Range, bool UseGlobal, SourceLocation PlacementLParen,
8594	MultiExprArg PlacementArgs, SourceLocation PlacementRParen,
8595	SourceRange TypeIdParens, QualType AllocType,
8596	TypeSourceInfo AllocTypeInfo, std::optional<Expr > ArraySize,
8597	SourceRange DirectInitRange, Expr *Initializer);
8598
8599	/// Determine whether \p FD is an aligned allocation or deallocation
8600	/// function that is unavailable.
8601	bool isUnavailableAlignedAllocationFunction(const FunctionDecl &FD) const;
8602
8603	/// Produce diagnostics if \p FD is an aligned allocation or deallocation
8604	/// function that is unavailable.
8605	void diagnoseUnavailableAlignedAllocation(const FunctionDecl &FD,
8606	SourceLocation Loc);
8607
8608	/// Checks that a type is suitable as the allocated type
8609	/// in a new-expression.
8610	bool CheckAllocatedType(QualType AllocType, SourceLocation Loc,
8611	SourceRange R);
8612
8613	/// Finds the overloads of operator new and delete that are appropriate
8614	/// for the allocation.
8615	bool FindAllocationFunctions(
8616	SourceLocation StartLoc, SourceRange Range,
8617	AllocationFunctionScope NewScope, AllocationFunctionScope DeleteScope,
8618	QualType AllocType, bool IsArray, ImplicitAllocationParameters &IAP,
8619	MultiExprArg PlaceArgs, FunctionDecl *&OperatorNew,
8620	FunctionDecl &OperatorDelete, bool* Diagnose = true);
8621
8622	/// DeclareGlobalNewDelete - Declare the global forms of operator new and
8623	/// delete. These are:
8624	/// @code
8625	/// // C++03:
8626	/// void operator new(std::size_t) throw(std::bad_alloc);*
8627	/// void operator new[](std::size_t) throw(std::bad_alloc);*
8628	/// void operator delete(void ) throw();*
8629	/// void operator delete[](void ) throw();*
8630	/// // C++11:
8631	/// void operator new(std::size_t);*
8632	/// void operator new[](std::size_t);*
8633	/// void operator delete(void ) noexcept;*
8634	/// void operator delete[](void ) noexcept;*
8635	/// // C++1y:
8636	/// void operator new(std::size_t);*
8637	/// void operator new[](std::size_t);*
8638	/// void operator delete(void ) noexcept;*
8639	/// void operator delete[](void ) noexcept;*
8640	/// void operator delete(void , std::size_t) noexcept;*
8641	/// void operator delete[](void , std::size_t) noexcept;*
8642	/// @endcode
8643	/// Note that the placement and nothrow forms of new are not* implicitly*
8644	/// declared. Their use requires including \<new\>.
8645	void DeclareGlobalNewDelete();
8646	void DeclareGlobalAllocationFunction(DeclarationName Name, QualType Return,
8647	ArrayRef<QualType> Params);
8648
8649	bool FindDeallocationFunction(SourceLocation StartLoc, CXXRecordDecl *RD,
8650	DeclarationName Name, FunctionDecl *&Operator,
8651	ImplicitDeallocationParameters,
8652	bool Diagnose = true);
8653	FunctionDecl *FindUsualDeallocationFunction(SourceLocation StartLoc,
8654	ImplicitDeallocationParameters,
8655	DeclarationName Name,
8656	bool Diagnose = true);
8657	FunctionDecl *FindDeallocationFunctionForDestructor(SourceLocation StartLoc,
8658	CXXRecordDecl *RD,
8659	bool Diagnose,
8660	bool LookForGlobal,
8661	DeclarationName Name);
8662
8663	/// ActOnCXXDelete - Parsed a C++ 'delete' expression (C++ 5.3.5), as in:
8664	/// @code ::delete ptr; @endcode
8665	/// or
8666	/// @code delete [] ptr; @endcode
8667	ExprResult ActOnCXXDelete(SourceLocation StartLoc, bool UseGlobal,
8668	bool ArrayForm, Expr *Operand);
8669	void CheckVirtualDtorCall(CXXDestructorDecl *dtor, SourceLocation Loc,
8670	bool IsDelete, bool CallCanBeVirtual,
8671	bool WarnOnNonAbstractTypes,
8672	SourceLocation DtorLoc);
8673
8674	ExprResult ActOnNoexceptExpr(SourceLocation KeyLoc, SourceLocation LParen,
8675	Expr *Operand, SourceLocation RParen);
8676	ExprResult BuildCXXNoexceptExpr(SourceLocation KeyLoc, Expr *Operand,
8677	SourceLocation RParen);
8678
8679	ExprResult ActOnStartCXXMemberReference(Scope S, Expr Base,
8680	SourceLocation OpLoc,
8681	tok::TokenKind OpKind,
8682	ParsedType &ObjectType,
8683	bool &MayBePseudoDestructor);
8684
8685	ExprResult BuildPseudoDestructorExpr(
8686	Expr *Base, SourceLocation OpLoc, tok::TokenKind OpKind,
8687	const CXXScopeSpec &SS, TypeSourceInfo *ScopeType, SourceLocation CCLoc,
8688	SourceLocation TildeLoc, PseudoDestructorTypeStorage DestroyedType);
8689
8690	ExprResult ActOnPseudoDestructorExpr(
8691	Scope S, Expr Base, SourceLocation OpLoc, tok::TokenKind OpKind,
8692	CXXScopeSpec &SS, UnqualifiedId &FirstTypeName, SourceLocation CCLoc,
8693	SourceLocation TildeLoc, UnqualifiedId &SecondTypeName);
8694
8695	ExprResult ActOnPseudoDestructorExpr(Scope S, Expr Base,
8696	SourceLocation OpLoc,
8697	tok::TokenKind OpKind,
8698	SourceLocation TildeLoc,
8699	const DeclSpec &DS);
8700
8701	/// MaybeCreateExprWithCleanups - If the current full-expression
8702	/// requires any cleanups, surround it with a ExprWithCleanups node.
8703	/// Otherwise, just returns the passed-in expression.
8704	Expr MaybeCreateExprWithCleanups(Expr SubExpr);
8705	Stmt MaybeCreateStmtWithCleanups(Stmt SubStmt);
8706	ExprResult MaybeCreateExprWithCleanups(ExprResult SubExpr);
8707
8708	ExprResult ActOnFinishFullExpr(Expr Expr, bool* DiscardedValue) {
8709	return ActOnFinishFullExpr(
8710	Expr, CC: Expr ? Expr->getExprLoc() : SourceLocation (), DiscardedValue);
8711	}
8712	ExprResult ActOnFinishFullExpr(Expr *Expr, SourceLocation CC,
8713	bool DiscardedValue, bool IsConstexpr = false,
8714	bool IsTemplateArgument = false);
8715	StmtResult ActOnFinishFullStmt(Stmt *Stmt);
8716
8717	/// Process the expression contained within a decltype. For such expressions,
8718	/// certain semantic checks on temporaries are delayed until this point, and
8719	/// are omitted for the 'topmost' call in the decltype expression. If the
8720	/// topmost call bound a temporary, strip that temporary off the expression.
8721	ExprResult ActOnDecltypeExpression(Expr *E);
8722
8723	bool checkLiteralOperatorId(const CXXScopeSpec &SS, const UnqualifiedId &Id,
8724	bool IsUDSuffix);
8725
8726	bool isUsualDeallocationFunction(const CXXMethodDecl *FD);
8727
8728	ConditionResult ActOnConditionVariable(Decl *ConditionVar,
8729	SourceLocation StmtLoc,
8730	ConditionKind CK);
8731
8732	/// Check the use of the given variable as a C++ condition in an if,
8733	/// while, do-while, or switch statement.
8734	ExprResult CheckConditionVariable(VarDecl *ConditionVar,
8735	SourceLocation StmtLoc, ConditionKind CK);
8736
8737	/// CheckCXXBooleanCondition - Returns true if conversion to bool is invalid.
8738	ExprResult CheckCXXBooleanCondition(Expr CondExpr, bool* IsConstexpr = false);
8739
8740	/// Helper function to determine whether this is the (deprecated) C++
8741	/// conversion from a string literal to a pointer to non-const char or
8742	/// non-const wchar_t (for narrow and wide string literals,
8743	/// respectively).
8744	bool IsStringLiteralToNonConstPointerConversion(Expr *From, QualType ToType);
8745
8746	/// PerformImplicitConversion - Perform an implicit conversion of the
8747	/// expression From to the type ToType using the pre-computed implicit
8748	/// conversion sequence ICS. Returns the converted
8749	/// expression. Action is the kind of conversion we're performing,
8750	/// used in the error message.
8751	ExprResult PerformImplicitConversion(
8752	Expr From, QualType ToType, const* ImplicitConversionSequence &ICS,
8753	AssignmentAction Action,
8754	CheckedConversionKind CCK = CheckedConversionKind::Implicit);
8755
8756	/// PerformImplicitConversion - Perform an implicit conversion of the
8757	/// expression From to the type ToType by following the standard
8758	/// conversion sequence SCS. Returns the converted
8759	/// expression. Flavor is the context in which we're performing this
8760	/// conversion, for use in error messages.
8761	ExprResult PerformImplicitConversion(Expr *From, QualType ToType,
8762	const StandardConversionSequence &SCS,
8763	AssignmentAction Action,
8764	CheckedConversionKind CCK);
8765
8766	bool CheckTypeTraitArity(unsigned Arity, SourceLocation Loc, size_t N);
8767
8768	/// Parsed one of the type trait support pseudo-functions.
8769	ExprResult ActOnTypeTrait(TypeTrait Kind, SourceLocation KWLoc,
8770	ArrayRef<ParsedType> Args,
8771	SourceLocation RParenLoc);
8772	ExprResult BuildTypeTrait(TypeTrait Kind, SourceLocation KWLoc,
8773	ArrayRef<TypeSourceInfo *> Args,
8774	SourceLocation RParenLoc);
8775
8776	/// ActOnArrayTypeTrait - Parsed one of the binary type trait support
8777	/// pseudo-functions.
8778	ExprResult ActOnArrayTypeTrait(ArrayTypeTrait ATT, SourceLocation KWLoc,
8779	ParsedType LhsTy, Expr *DimExpr,
8780	SourceLocation RParen);
8781
8782	ExprResult BuildArrayTypeTrait(ArrayTypeTrait ATT, SourceLocation KWLoc,
8783	TypeSourceInfo TSInfo, Expr DimExpr,
8784	SourceLocation RParen);
8785
8786	/// ActOnExpressionTrait - Parsed one of the unary type trait support
8787	/// pseudo-functions.
8788	ExprResult ActOnExpressionTrait(ExpressionTrait OET, SourceLocation KWLoc,
8789	Expr *Queried, SourceLocation RParen);
8790
8791	ExprResult BuildExpressionTrait(ExpressionTrait OET, SourceLocation KWLoc,
8792	Expr *Queried, SourceLocation RParen);
8793
8794	QualType CheckPointerToMemberOperands( // C++ 5.5
8795	ExprResult &LHS, ExprResult &RHS, ExprValueKind &VK, SourceLocation OpLoc,
8796	bool isIndirect);
8797	QualType CheckVectorConditionalTypes(ExprResult &Cond, ExprResult &LHS,
8798	ExprResult &RHS,
8799	SourceLocation QuestionLoc);
8800
8801	//// Determines if a type is trivially relocatable
8802	/// according to the C++26 rules.
8803	// FIXME: This is in Sema because it requires
8804	// overload resolution, can we move to ASTContext?
8805	bool IsCXXTriviallyRelocatableType(QualType T);
8806	bool IsCXXTriviallyRelocatableType(const CXXRecordDecl &RD);
8807
8808	/// Check the operands of ?: under C++ semantics.
8809	///
8810	/// See C++ [expr.cond]. Note that LHS is never null, even for the GNU x ?: y
8811	/// extension. In this case, LHS == Cond. (But they're not aliases.)
8812	///
8813	/// This function also implements GCC's vector extension and the
8814	/// OpenCL/ext_vector_type extension for conditionals. The vector extensions
8815	/// permit the use of a?b:c where the type of a is that of a integer vector
8816	/// with the same number of elements and size as the vectors of b and c. If
8817	/// one of either b or c is a scalar it is implicitly converted to match the
8818	/// type of the vector. Otherwise the expression is ill-formed. If both b and
8819	/// c are scalars, then b and c are checked and converted to the type of a if
8820	/// possible.
8821	///
8822	/// The expressions are evaluated differently for GCC's and OpenCL's
8823	/// extensions. For the GCC extension, the ?: operator is evaluated as
8824	/// (a[0] != 0 ? b[0] : c[0], .. , a[n] != 0 ? b[n] : c[n]).
8825	/// For the OpenCL extensions, the ?: operator is evaluated as
8826	/// (most-significant-bit-set(a[0]) ? b[0] : c[0], .. ,
8827	/// most-significant-bit-set(a[n]) ? b[n] : c[n]).
8828	QualType CXXCheckConditionalOperands( // C++ 5.16
8829	ExprResult &cond, ExprResult &lhs, ExprResult &rhs, ExprValueKind &VK,
8830	ExprObjectKind &OK, SourceLocation questionLoc);
8831
8832	/// Find a merged pointer type and convert the two expressions to it.
8833	///
8834	/// This finds the composite pointer type for \p E1 and \p E2 according to
8835	/// C++2a [expr.type]p3. It converts both expressions to this type and returns
8836	/// it. It does not emit diagnostics (FIXME: that's not true if \p
8837	/// ConvertArgs is \c true).
8838	///
8839	/// \param Loc The location of the operator requiring these two expressions to
8840	/// be converted to the composite pointer type.
8841	///
8842	/// \param ConvertArgs If \c false, do not convert E1 and E2 to the target
8843	/// type.
8844	QualType FindCompositePointerType(SourceLocation Loc, Expr &E1, Expr &E2,
8845	bool ConvertArgs = true);
8846	QualType FindCompositePointerType(SourceLocation Loc, ExprResult &E1,
8847	ExprResult &E2, bool ConvertArgs = true) {
8848	Expr E1Tmp = E1.get(), E2Tmp = E2.get();
8849	QualType Composite =
8850	FindCompositePointerType(Loc, E1&: E1Tmp, E2&: E2Tmp, ConvertArgs);
8851	E1 = E1Tmp;
8852	E2 = E2Tmp;
8853	return Composite;
8854	}
8855
8856	/// MaybeBindToTemporary - If the passed in expression has a record type with
8857	/// a non-trivial destructor, this will return CXXBindTemporaryExpr. Otherwise
8858	/// it simply returns the passed in expression.
8859	ExprResult MaybeBindToTemporary(Expr *E);
8860
8861	/// IgnoredValueConversions - Given that an expression's result is
8862	/// syntactically ignored, perform any conversions that are
8863	/// required.
8864	ExprResult IgnoredValueConversions(Expr *E);
8865
8866	ExprResult CheckUnevaluatedOperand(Expr *E);
8867
8868	IfExistsResult
8869	CheckMicrosoftIfExistsSymbol(Scope *S, CXXScopeSpec &SS,
8870	const DeclarationNameInfo &TargetNameInfo);
8871
8872	IfExistsResult CheckMicrosoftIfExistsSymbol(Scope *S,
8873	SourceLocation KeywordLoc,
8874	bool IsIfExists, CXXScopeSpec &SS,
8875	UnqualifiedId &Name);
8876
8877	RequiresExprBodyDecl *
8878	ActOnStartRequiresExpr(SourceLocation RequiresKWLoc,
8879	ArrayRef<ParmVarDecl *> LocalParameters,
8880	Scope *BodyScope);
8881	void ActOnFinishRequiresExpr();
8882	concepts::Requirement ActOnSimpleRequirement(Expr E);
8883	concepts::Requirement *ActOnTypeRequirement(SourceLocation TypenameKWLoc,
8884	CXXScopeSpec &SS,
8885	SourceLocation NameLoc,
8886	const IdentifierInfo *TypeName,
8887	TemplateIdAnnotation *TemplateId);
8888	concepts::Requirement ActOnCompoundRequirement(Expr E,
8889	SourceLocation NoexceptLoc);
8890	concepts::Requirement *ActOnCompoundRequirement(
8891	Expr *E, SourceLocation NoexceptLoc, CXXScopeSpec &SS,
8892	TemplateIdAnnotation TypeConstraint, unsigned* Depth);
8893	concepts::Requirement ActOnNestedRequirement(Expr Constraint);
8894	concepts::ExprRequirement *BuildExprRequirement(
8895	Expr E, bool* IsSatisfied, SourceLocation NoexceptLoc,
8896	concepts::ExprRequirement::ReturnTypeRequirement ReturnTypeRequirement);
8897	concepts::ExprRequirement *BuildExprRequirement(
8898	concepts::Requirement::SubstitutionDiagnostic *ExprSubstDiag,
8899	bool IsSatisfied, SourceLocation NoexceptLoc,
8900	concepts::ExprRequirement::ReturnTypeRequirement ReturnTypeRequirement);
8901	concepts::TypeRequirement BuildTypeRequirement(TypeSourceInfo Type);
8902	concepts::TypeRequirement *BuildTypeRequirement(
8903	concepts::Requirement::SubstitutionDiagnostic *SubstDiag);
8904	concepts::NestedRequirement BuildNestedRequirement(Expr E);
8905	concepts::NestedRequirement *
8906	BuildNestedRequirement(StringRef InvalidConstraintEntity,
8907	const ASTConstraintSatisfaction &Satisfaction);
8908	ExprResult ActOnRequiresExpr(SourceLocation RequiresKWLoc,
8909	RequiresExprBodyDecl *Body,
8910	SourceLocation LParenLoc,
8911	ArrayRef<ParmVarDecl *> LocalParameters,
8912	SourceLocation RParenLoc,
8913	ArrayRef<concepts::Requirement *> Requirements,
8914	SourceLocation ClosingBraceLoc);
8915
8916	private:
8917	ExprResult BuiltinOperatorNewDeleteOverloaded(ExprResult TheCallResult,
8918	bool IsDelete);
8919
8920	void AnalyzeDeleteExprMismatch(const CXXDeleteExpr *DE);
8921	void AnalyzeDeleteExprMismatch(FieldDecl *Field, SourceLocation DeleteLoc,
8922	bool DeleteWasArrayForm);
8923
8924	///@}
8925
8926	//
8927	//
8928	// -------------------------------------------------------------------------
8929	//
8930	//
8931
8932	/// \name Member Access Expressions
8933	/// Implementations are in SemaExprMember.cpp
8934	///@{
8935
8936	public:
8937	/// Check whether an expression might be an implicit class member access.
8938	bool isPotentialImplicitMemberAccess(const CXXScopeSpec &SS, LookupResult &R,
8939	bool IsAddressOfOperand);
8940
8941	/// Builds an expression which might be an implicit member expression.
8942	ExprResult BuildPossibleImplicitMemberExpr(
8943	const CXXScopeSpec &SS, SourceLocation TemplateKWLoc, LookupResult &R,
8944	const TemplateArgumentListInfo TemplateArgs, const* Scope *S);
8945
8946	/// Builds an implicit member access expression. The current context
8947	/// is known to be an instance method, and the given unqualified lookup
8948	/// set is known to contain only instance members, at least one of which
8949	/// is from an appropriate type.
8950	ExprResult
8951	BuildImplicitMemberExpr(const CXXScopeSpec &SS, SourceLocation TemplateKWLoc,
8952	LookupResult &R,
8953	const TemplateArgumentListInfo *TemplateArgs,
8954	bool IsDefiniteInstance, const Scope *S);
8955
8956	ExprResult ActOnDependentMemberExpr(
8957	Expr Base, QualType BaseType, bool* IsArrow, SourceLocation OpLoc,
8958	const CXXScopeSpec &SS, SourceLocation TemplateKWLoc,
8959	NamedDecl FirstQualifierInScope, const* DeclarationNameInfo &NameInfo,
8960	const TemplateArgumentListInfo *TemplateArgs);
8961
8962	/// The main callback when the parser finds something like
8963	/// expression . [nested-name-specifier] identifier
8964	/// expression -> [nested-name-specifier] identifier
8965	/// where 'identifier' encompasses a fairly broad spectrum of
8966	/// possibilities, including destructor and operator references.
8967	///
8968	/// \param OpKind either tok::arrow or tok::period
8969	/// \param ObjCImpDecl the current Objective-C \@implementation
8970	/// decl; this is an ugly hack around the fact that Objective-C
8971	/// \@implementations aren't properly put in the context chain
8972	ExprResult ActOnMemberAccessExpr(Scope S, Expr Base, SourceLocation OpLoc,
8973	tok::TokenKind OpKind, CXXScopeSpec &SS,
8974	SourceLocation TemplateKWLoc,
8975	UnqualifiedId &Member, Decl *ObjCImpDecl);
8976
8977	MemberExpr *
8978	BuildMemberExpr(Expr Base, bool* IsArrow, SourceLocation OpLoc,
8979	NestedNameSpecifierLoc NNS, SourceLocation TemplateKWLoc,
8980	ValueDecl *Member, DeclAccessPair FoundDecl,
8981	bool HadMultipleCandidates,
8982	const DeclarationNameInfo &MemberNameInfo, QualType Ty,
8983	ExprValueKind VK, ExprObjectKind OK,
8984	const TemplateArgumentListInfo TemplateArgs = nullptr*);
8985
8986	// Check whether the declarations we found through a nested-name
8987	// specifier in a member expression are actually members of the base
8988	// type. The restriction here is:
8989	//
8990	// C++ [expr.ref]p2:
8991	// ... In these cases, the id-expression shall name a
8992	// member of the class or of one of its base classes.
8993	//
8994	// So it's perfectly legitimate for the nested-name specifier to name
8995	// an unrelated class, and for us to find an overload set including
8996	// decls from classes which are not superclasses, as long as the decl
8997	// we actually pick through overload resolution is from a superclass.
8998	bool CheckQualifiedMemberReference(Expr *BaseExpr, QualType BaseType,
8999	const CXXScopeSpec &SS,
9000	const LookupResult &R);
9001
9002	// This struct is for use by ActOnMemberAccess to allow
9003	// BuildMemberReferenceExpr to be able to reinvoke ActOnMemberAccess after
9004	// changing the access operator from a '.' to a '->' (to see if that is the
9005	// change needed to fix an error about an unknown member, e.g. when the class
9006	// defines a custom operator->).
9007	struct ActOnMemberAccessExtraArgs {
9008	Scope *S;
9009	UnqualifiedId &Id;
9010	Decl *ObjCImpDecl;
9011	};
9012
9013	ExprResult BuildMemberReferenceExpr(
9014	Expr Base, QualType BaseType, SourceLocation OpLoc, bool* IsArrow,
9015	CXXScopeSpec &SS, SourceLocation TemplateKWLoc,
9016	NamedDecl FirstQualifierInScope, const* DeclarationNameInfo &NameInfo,
9017	const TemplateArgumentListInfo TemplateArgs, const* Scope *S,
9018	ActOnMemberAccessExtraArgs ExtraArgs = nullptr*);
9019
9020	ExprResult
9021	BuildMemberReferenceExpr(Expr *Base, QualType BaseType, SourceLocation OpLoc,
9022	bool IsArrow, const CXXScopeSpec &SS,
9023	SourceLocation TemplateKWLoc,
9024	NamedDecl *FirstQualifierInScope, LookupResult &R,
9025	const TemplateArgumentListInfo *TemplateArgs,
9026	const Scope S, bool* SuppressQualifierCheck = false,
9027	ActOnMemberAccessExtraArgs ExtraArgs = nullptr*);
9028
9029	ExprResult BuildFieldReferenceExpr(Expr BaseExpr, bool* IsArrow,
9030	SourceLocation OpLoc,
9031	const CXXScopeSpec &SS, FieldDecl *Field,
9032	DeclAccessPair FoundDecl,
9033	const DeclarationNameInfo &MemberNameInfo);
9034
9035	/// Perform conversions on the LHS of a member access expression.
9036	ExprResult PerformMemberExprBaseConversion(Expr Base, bool* IsArrow);
9037
9038	ExprResult BuildAnonymousStructUnionMemberReference(
9039	const CXXScopeSpec &SS, SourceLocation nameLoc,
9040	IndirectFieldDecl *indirectField,
9041	DeclAccessPair FoundDecl = DeclAccessPair::make(D: nullptr, AS: AS_none),
9042	Expr baseObjectExpr = nullptr*, SourceLocation opLoc = SourceLocation ());
9043
9044	private:
9045	void CheckMemberAccessOfNoDeref(const MemberExpr *E);
9046
9047	///@}
9048
9049	//
9050	//
9051	// -------------------------------------------------------------------------
9052	//
9053	//
9054
9055	/// \name Initializers
9056	/// Implementations are in SemaInit.cpp
9057	///@{
9058
9059	public:
9060	/// Stack of types that correspond to the parameter entities that are
9061	/// currently being copy-initialized. Can be empty.
9062	llvm::SmallVector<QualType, `4`> CurrentParameterCopyTypes;
9063
9064	llvm::DenseMap<unsigned, CXXDeductionGuideDecl *>
9065	AggregateDeductionCandidates;
9066
9067	bool IsStringInit(Expr Init, const* ArrayType *AT);
9068
9069	/// Determine whether we can perform aggregate initialization for the purposes
9070	/// of overload resolution.
9071	bool CanPerformAggregateInitializationForOverloadResolution(
9072	const InitializedEntity &Entity, InitListExpr *From);
9073
9074	ExprResult ActOnDesignatedInitializer(Designation &Desig,
9075	SourceLocation EqualOrColonLoc,
9076	bool GNUSyntax, ExprResult Init);
9077
9078	/// Check that the lifetime of the initializer (and its subobjects) is
9079	/// sufficient for initializing the entity, and perform lifetime extension
9080	/// (when permitted) if not.
9081	void checkInitializerLifetime(const InitializedEntity &Entity, Expr *Init);
9082
9083	MaterializeTemporaryExpr *
9084	CreateMaterializeTemporaryExpr(QualType T, Expr *Temporary,
9085	bool BoundToLvalueReference);
9086
9087	/// If \p E is a prvalue denoting an unmaterialized temporary, materialize
9088	/// it as an xvalue. In C++98, the result will still be a prvalue, because
9089	/// we don't have xvalues there.
9090	ExprResult TemporaryMaterializationConversion(Expr *E);
9091
9092	ExprResult PerformQualificationConversion(
9093	Expr *E, QualType Ty, ExprValueKind VK = VK_PRValue,
9094	CheckedConversionKind CCK = CheckedConversionKind::Implicit);
9095
9096	bool CanPerformCopyInitialization(const InitializedEntity &Entity,
9097	ExprResult Init);
9098	ExprResult PerformCopyInitialization(const InitializedEntity &Entity,
9099	SourceLocation EqualLoc, ExprResult Init,
9100	bool TopLevelOfInitList = false,
9101	bool AllowExplicit = false);
9102
9103	QualType DeduceTemplateSpecializationFromInitializer(
9104	TypeSourceInfo TInfo, const* InitializedEntity &Entity,
9105	const InitializationKind &Kind, MultiExprArg Init);
9106
9107	///@}
9108
9109	//
9110	//
9111	// -------------------------------------------------------------------------
9112	//
9113	//
9114
9115	/// \name C++ Lambda Expressions
9116	/// Implementations are in SemaLambda.cpp
9117	///@{
9118
9119	public:
9120	/// Create a new lambda closure type.
9121	CXXRecordDecl *createLambdaClosureType(SourceRange IntroducerRange,
9122	TypeSourceInfo *Info,
9123	unsigned LambdaDependencyKind,
9124	LambdaCaptureDefault CaptureDefault);
9125
9126	/// Number lambda for linkage purposes if necessary.
9127	void handleLambdaNumbering(CXXRecordDecl Class, CXXMethodDecl Method,
9128	std::optional<CXXRecordDecl::LambdaNumbering>
9129	NumberingOverride = std::nullopt);
9130
9131	/// Endow the lambda scope info with the relevant properties.
9132	void buildLambdaScope(sema::LambdaScopeInfo LSI, CXXMethodDecl CallOperator,
9133	SourceRange IntroducerRange,
9134	LambdaCaptureDefault CaptureDefault,
9135	SourceLocation CaptureDefaultLoc, bool ExplicitParams,
9136	bool Mutable);
9137
9138	CXXMethodDecl *CreateLambdaCallOperator(SourceRange IntroducerRange,
9139	CXXRecordDecl *Class);
9140
9141	void AddTemplateParametersToLambdaCallOperator(
9142	CXXMethodDecl CallOperator, CXXRecordDecl Class,
9143	TemplateParameterList *TemplateParams);
9144
9145	void
9146	CompleteLambdaCallOperator(CXXMethodDecl *Method, SourceLocation LambdaLoc,
9147	SourceLocation CallOperatorLoc,
9148	const AssociatedConstraint &TrailingRequiresClause,
9149	TypeSourceInfo *MethodTyInfo,
9150	ConstexprSpecKind ConstexprKind, StorageClass SC,
9151	ArrayRef<ParmVarDecl *> Params,
9152	bool HasExplicitResultType);
9153
9154	/// Returns true if the explicit object parameter was invalid.
9155	bool DiagnoseInvalidExplicitObjectParameterInLambda(CXXMethodDecl *Method,
9156	SourceLocation CallLoc);
9157
9158	/// Perform initialization analysis of the init-capture and perform
9159	/// any implicit conversions such as an lvalue-to-rvalue conversion if
9160	/// not being used to initialize a reference.
9161	ParsedType actOnLambdaInitCaptureInitialization(
9162	SourceLocation Loc, bool ByRef, SourceLocation EllipsisLoc,
9163	IdentifierInfo Id, LambdaCaptureInitKind InitKind, Expr &Init) {
9164	return ParsedType::make(P: buildLambdaInitCaptureInitialization(
9165	Loc, ByRef, EllipsisLoc, NumExpansions: std::nullopt, Id,
9166	DirectInit: InitKind != LambdaCaptureInitKind::CopyInit, Init));
9167	}
9168	QualType buildLambdaInitCaptureInitialization(SourceLocation Loc, bool ByRef,
9169	SourceLocation EllipsisLoc,
9170	UnsignedOrNone NumExpansions,
9171	IdentifierInfo *Id,
9172	bool DirectInit, Expr *&Init);
9173
9174	/// Create a dummy variable within the declcontext of the lambda's
9175	/// call operator, for name lookup purposes for a lambda init capture.
9176	///
9177	/// CodeGen handles emission of lambda captures, ignoring these dummy
9178	/// variables appropriately.
9179	VarDecl *createLambdaInitCaptureVarDecl(
9180	SourceLocation Loc, QualType InitCaptureType, SourceLocation EllipsisLoc,
9181	IdentifierInfo Id, unsigned* InitStyle, Expr Init, DeclContext DeclCtx);
9182
9183	/// Add an init-capture to a lambda scope.
9184	void addInitCapture(sema::LambdaScopeInfo LSI, VarDecl Var, bool ByRef);
9185
9186	/// Note that we have finished the explicit captures for the
9187	/// given lambda.
9188	void finishLambdaExplicitCaptures(sema::LambdaScopeInfo *LSI);
9189
9190	/// Deduce a block or lambda's return type based on the return
9191	/// statements present in the body.
9192	void deduceClosureReturnType(sema::CapturingScopeInfo &CSI);
9193
9194	/// Once the Lambdas capture are known, we can start to create the closure,
9195	/// call operator method, and keep track of the captures.
9196	/// We do the capture lookup here, but they are not actually captured until
9197	/// after we know what the qualifiers of the call operator are.
9198	void ActOnLambdaExpressionAfterIntroducer(LambdaIntroducer &Intro,
9199	Scope *CurContext);
9200
9201	/// This is called after parsing the explicit template parameter list
9202	/// on a lambda (if it exists) in C++2a.
9203	void ActOnLambdaExplicitTemplateParameterList(LambdaIntroducer &Intro,
9204	SourceLocation LAngleLoc,
9205	ArrayRef<NamedDecl *> TParams,
9206	SourceLocation RAngleLoc,
9207	ExprResult RequiresClause);
9208
9209	void ActOnLambdaClosureQualifiers(LambdaIntroducer &Intro,
9210	SourceLocation MutableLoc);
9211
9212	void ActOnLambdaClosureParameters(
9213	Scope *LambdaScope,
9214	MutableArrayRef<DeclaratorChunk::ParamInfo> ParamInfo);
9215
9216	/// ActOnStartOfLambdaDefinition - This is called just before we start
9217	/// parsing the body of a lambda; it analyzes the explicit captures and
9218	/// arguments, and sets up various data-structures for the body of the
9219	/// lambda.
9220	void ActOnStartOfLambdaDefinition(LambdaIntroducer &Intro,
9221	Declarator &ParamInfo, const DeclSpec &DS);
9222
9223	/// ActOnLambdaError - If there is an error parsing a lambda, this callback
9224	/// is invoked to pop the information about the lambda.
9225	void ActOnLambdaError(SourceLocation StartLoc, Scope *CurScope,
9226	bool IsInstantiation = false);
9227
9228	/// ActOnLambdaExpr - This is called when the body of a lambda expression
9229	/// was successfully completed.
9230	ExprResult ActOnLambdaExpr(SourceLocation StartLoc, Stmt *Body);
9231
9232	/// Does copying/destroying the captured variable have side effects?
9233	bool CaptureHasSideEffects(const sema::Capture &From);
9234
9235	/// Diagnose if an explicit lambda capture is unused. Returns true if a
9236	/// diagnostic is emitted.
9237	bool DiagnoseUnusedLambdaCapture(SourceRange CaptureRange,
9238	SourceRange FixItRange,
9239	const sema::Capture &From);
9240
9241	/// Build a FieldDecl suitable to hold the given capture.
9242	FieldDecl BuildCaptureField(RecordDecl RD, const sema::Capture &Capture);
9243
9244	/// Initialize the given capture with a suitable expression.
9245	ExprResult BuildCaptureInit(const sema::Capture &Capture,
9246	SourceLocation ImplicitCaptureLoc,
9247	bool IsOpenMPMapping = false);
9248
9249	/// Complete a lambda-expression having processed and attached the
9250	/// lambda body.
9251	ExprResult BuildLambdaExpr(SourceLocation StartLoc, SourceLocation EndLoc);
9252
9253	/// Get the return type to use for a lambda's conversion function(s) to
9254	/// function pointer type, given the type of the call operator.
9255	QualType
9256	getLambdaConversionFunctionResultType(const FunctionProtoType *CallOpType,
9257	CallingConv CC);
9258
9259	ExprResult BuildBlockForLambdaConversion(SourceLocation CurrentLocation,
9260	SourceLocation ConvLocation,
9261	CXXConversionDecl Conv, Expr Src);
9262
9263	class LambdaScopeForCallOperatorInstantiationRAII
9264	: private FunctionScopeRAII {
9265	public:
9266	LambdaScopeForCallOperatorInstantiationRAII(
9267	Sema &SemasRef, FunctionDecl *FD, MultiLevelTemplateArgumentList MLTAL,
9268	LocalInstantiationScope &Scope,
9269	bool ShouldAddDeclsFromParentScope = true);
9270	};
9271
9272	/// Compute the mangling number context for a lambda expression or
9273	/// block literal. Also return the extra mangling decl if any.
9274	///
9275	/// \param DC - The DeclContext containing the lambda expression or
9276	/// block literal.
9277	std::tuple<MangleNumberingContext , Decl >
9278	getCurrentMangleNumberContext(const DeclContext *DC);
9279
9280	///@}
9281
9282	//
9283	//
9284	// -------------------------------------------------------------------------
9285	//
9286	//
9287
9288	/// \name Name Lookup
9289	///
9290	/// These routines provide name lookup that is used during semantic
9291	/// analysis to resolve the various kinds of names (identifiers,
9292	/// overloaded operator names, constructor names, etc.) into zero or
9293	/// more declarations within a particular scope. The major entry
9294	/// points are LookupName, which performs unqualified name lookup,
9295	/// and LookupQualifiedName, which performs qualified name lookup.
9296	///
9297	/// All name lookup is performed based on some specific criteria,
9298	/// which specify what names will be visible to name lookup and how
9299	/// far name lookup should work. These criteria are important both
9300	/// for capturing language semantics (certain lookups will ignore
9301	/// certain names, for example) and for performance, since name
9302	/// lookup is often a bottleneck in the compilation of C++. Name
9303	/// lookup criteria is specified via the LookupCriteria enumeration.
9304	///
9305	/// The results of name lookup can vary based on the kind of name
9306	/// lookup performed, the current language, and the translation
9307	/// unit. In C, for example, name lookup will either return nothing
9308	/// (no entity found) or a single declaration. In C++, name lookup
9309	/// can additionally refer to a set of overloaded functions or
9310	/// result in an ambiguity. All of the possible results of name
9311	/// lookup are captured by the LookupResult class, which provides
9312	/// the ability to distinguish among them.
9313	///
9314	/// Implementations are in SemaLookup.cpp
9315	///@{
9316
9317	public:
9318	/// Tracks whether we are in a context where typo correction is
9319	/// disabled.
9320	bool DisableTypoCorrection;
9321
9322	/// The number of typos corrected by CorrectTypo.
9323	unsigned TyposCorrected;
9324
9325	typedef llvm::SmallSet<SourceLocation, `2`> SrcLocSet;
9326	typedef llvm::DenseMap<IdentifierInfo *, SrcLocSet> IdentifierSourceLocations;
9327
9328	/// A cache containing identifiers for which typo correction failed and
9329	/// their locations, so that repeated attempts to correct an identifier in a
9330	/// given location are ignored if typo correction already failed for it.
9331	IdentifierSourceLocations TypoCorrectionFailures;
9332
9333	/// SpecialMemberOverloadResult - The overloading result for a special member
9334	/// function.
9335	///
9336	/// This is basically a wrapper around PointerIntPair. The lowest bits of the
9337	/// integer are used to determine whether overload resolution succeeded.
9338	class SpecialMemberOverloadResult {
9339	public:
9340	enum Kind { NoMemberOrDeleted, Ambiguous, Success };
9341
9342	private:
9343	llvm::PointerIntPair<CXXMethodDecl *, `2`> Pair;
9344
9345	public:
9346	SpecialMemberOverloadResult() {}
9347	SpecialMemberOverloadResult(CXXMethodDecl *MD)
9348	: Pair (MD, MD->isDeleted() ? NoMemberOrDeleted : Success) {}
9349
9350	CXXMethodDecl getMethod() const* { return Pair.getPointer(); }
9351	void setMethod(CXXMethodDecl *MD) { Pair.setPointer(MD); }
9352
9353	Kind getKind() const { return static_cast<Kind>(Pair.getInt()); }
9354	void setKind(Kind K) { Pair.setInt(K); }
9355	};
9356
9357	class SpecialMemberOverloadResultEntry : public llvm::FastFoldingSetNode,
9358	public SpecialMemberOverloadResult {
9359	public:
9360	SpecialMemberOverloadResultEntry(const llvm::FoldingSetNodeID &ID)
9361	: FastFoldingSetNode (ID) {}
9362	};
9363
9364	/// A cache of special member function overload resolution results
9365	/// for C++ records.
9366	llvm::FoldingSet<SpecialMemberOverloadResultEntry> SpecialMemberCache;
9367
9368	enum class AcceptableKind { Visible, Reachable };
9369
9370	// Members have to be NamespaceDecl or TranslationUnitDecl.
9371	// TODO: make this is a typesafe union.
9372	typedef llvm::SmallSetVector<DeclContext *, `16`> AssociatedNamespaceSet;
9373	typedef llvm::SmallSetVector<CXXRecordDecl *, `16`> AssociatedClassSet;
9374
9375	/// Describes the kind of name lookup to perform.
9376	enum LookupNameKind {
9377	/// Ordinary name lookup, which finds ordinary names (functions,
9378	/// variables, typedefs, etc.) in C and most kinds of names
9379	/// (functions, variables, members, types, etc.) in C++.
9380	LookupOrdinaryName = `0`,
9381	/// Tag name lookup, which finds the names of enums, classes,
9382	/// structs, and unions.
9383	LookupTagName,
9384	/// Label name lookup.
9385	LookupLabel,
9386	/// Member name lookup, which finds the names of
9387	/// class/struct/union members.
9388	LookupMemberName,
9389	/// Look up of an operator name (e.g., operator+) for use with
9390	/// operator overloading. This lookup is similar to ordinary name
9391	/// lookup, but will ignore any declarations that are class members.
9392	LookupOperatorName,
9393	/// Look up a name following ~ in a destructor name. This is an ordinary
9394	/// lookup, but prefers tags to typedefs.
9395	LookupDestructorName,
9396	/// Look up of a name that precedes the '::' scope resolution
9397	/// operator in C++. This lookup completely ignores operator, object,
9398	/// function, and enumerator names (C++ [basic.lookup.qual]p1).
9399	LookupNestedNameSpecifierName,
9400	/// Look up a namespace name within a C++ using directive or
9401	/// namespace alias definition, ignoring non-namespace names (C++
9402	/// [basic.lookup.udir]p1).
9403	LookupNamespaceName,
9404	/// Look up all declarations in a scope with the given name,
9405	/// including resolved using declarations. This is appropriate
9406	/// for checking redeclarations for a using declaration.
9407	LookupUsingDeclName,
9408	/// Look up an ordinary name that is going to be redeclared as a
9409	/// name with linkage. This lookup ignores any declarations that
9410	/// are outside of the current scope unless they have linkage. See
9411	/// C99 6.2.2p4-5 and C++ [basic.link]p6.
9412	LookupRedeclarationWithLinkage,
9413	/// Look up a friend of a local class. This lookup does not look
9414	/// outside the innermost non-class scope. See C++11 [class.friend]p11.
9415	LookupLocalFriendName,
9416	/// Look up the name of an Objective-C protocol.
9417	LookupObjCProtocolName,
9418	/// Look up implicit 'self' parameter of an objective-c method.
9419	LookupObjCImplicitSelfParam,
9420	/// Look up the name of an OpenMP user-defined reduction operation.
9421	LookupOMPReductionName,
9422	/// Look up the name of an OpenMP user-defined mapper.
9423	LookupOMPMapperName,
9424	/// Look up any declaration with any name.
9425	LookupAnyName
9426	};
9427
9428	/// The possible outcomes of name lookup for a literal operator.
9429	enum LiteralOperatorLookupResult {
9430	/// The lookup resulted in an error.
9431	LOLR_Error,
9432	/// The lookup found no match but no diagnostic was issued.
9433	LOLR_ErrorNoDiagnostic,
9434	/// The lookup found a single 'cooked' literal operator, which
9435	/// expects a normal literal to be built and passed to it.
9436	LOLR_Cooked,
9437	/// The lookup found a single 'raw' literal operator, which expects
9438	/// a string literal containing the spelling of the literal token.
9439	LOLR_Raw,
9440	/// The lookup found an overload set of literal operator templates,
9441	/// which expect the characters of the spelling of the literal token to be
9442	/// passed as a non-type template argument pack.
9443	LOLR_Template,
9444	/// The lookup found an overload set of literal operator templates,
9445	/// which expect the character type and characters of the spelling of the
9446	/// string literal token to be passed as template arguments.
9447	LOLR_StringTemplatePack,
9448	};
9449
9450	SpecialMemberOverloadResult
9451	LookupSpecialMember(CXXRecordDecl D, CXXSpecialMemberKind SM, bool* ConstArg,
9452	bool VolatileArg, bool RValueThis, bool ConstThis,
9453	bool VolatileThis);
9454
9455	RedeclarationKind forRedeclarationInCurContext() const;
9456
9457	/// Look up a name, looking for a single declaration. Return
9458	/// null if the results were absent, ambiguous, or overloaded.
9459	///
9460	/// It is preferable to use the elaborated form and explicitly handle
9461	/// ambiguity and overloaded.
9462	NamedDecl *LookupSingleName(
9463	Scope *S, DeclarationName Name, SourceLocation Loc,
9464	LookupNameKind NameKind,
9465	RedeclarationKind Redecl = RedeclarationKind::NotForRedeclaration);
9466
9467	/// Lookup a builtin function, when name lookup would otherwise
9468	/// fail.
9469	bool LookupBuiltin(LookupResult &R);
9470	void LookupNecessaryTypesForBuiltin(Scope S, unsigned* ID);
9471
9472	/// Perform unqualified name lookup starting from a given
9473	/// scope.
9474	///
9475	/// Unqualified name lookup (C++ [basic.lookup.unqual], C99 6.2.1) is
9476	/// used to find names within the current scope. For example, 'x' in
9477	/// @code
9478	/// int x;
9479	/// int f() {
9480	/// return x; // unqualified name look finds 'x' in the global scope
9481	/// }
9482	/// @endcode
9483	///
9484	/// Different lookup criteria can find different names. For example, a
9485	/// particular scope can have both a struct and a function of the same
9486	/// name, and each can be found by certain lookup criteria. For more
9487	/// information about lookup criteria, see the documentation for the
9488	/// class LookupCriteria.
9489	///
9490	/// @param S The scope from which unqualified name lookup will
9491	/// begin. If the lookup criteria permits, name lookup may also search
9492	/// in the parent scopes.
9493	///
9494	/// @param [in,out] R Specifies the lookup to perform (e.g., the name to
9495	/// look up and the lookup kind), and is updated with the results of lookup
9496	/// including zero or more declarations and possibly additional information
9497	/// used to diagnose ambiguities.
9498	///
9499	/// @returns \c true if lookup succeeded and false otherwise.
9500	bool LookupName(LookupResult &R, Scope S, bool* AllowBuiltinCreation = false,
9501	bool ForceNoCPlusPlus = false);
9502
9503	/// Perform qualified name lookup into a given context.
9504	///
9505	/// Qualified name lookup (C++ [basic.lookup.qual]) is used to find
9506	/// names when the context of those names is explicit specified, e.g.,
9507	/// "std::vector" or "x->member", or as part of unqualified name lookup.
9508	///
9509	/// Different lookup criteria can find different names. For example, a
9510	/// particular scope can have both a struct and a function of the same
9511	/// name, and each can be found by certain lookup criteria. For more
9512	/// information about lookup criteria, see the documentation for the
9513	/// class LookupCriteria.
9514	///
9515	/// \param R captures both the lookup criteria and any lookup results found.
9516	///
9517	/// \param LookupCtx The context in which qualified name lookup will
9518	/// search. If the lookup criteria permits, name lookup may also search
9519	/// in the parent contexts or (for C++ classes) base classes.
9520	///
9521	/// \param InUnqualifiedLookup true if this is qualified name lookup that
9522	/// occurs as part of unqualified name lookup.
9523	///
9524	/// \returns true if lookup succeeded, false if it failed.
9525	bool LookupQualifiedName(LookupResult &R, DeclContext *LookupCtx,
9526	bool InUnqualifiedLookup = false);
9527
9528	/// Performs qualified name lookup or special type of lookup for
9529	/// "__super::" scope specifier.
9530	///
9531	/// This routine is a convenience overload meant to be called from contexts
9532	/// that need to perform a qualified name lookup with an optional C++ scope
9533	/// specifier that might require special kind of lookup.
9534	///
9535	/// \param R captures both the lookup criteria and any lookup results found.
9536	///
9537	/// \param LookupCtx The context in which qualified name lookup will
9538	/// search.
9539	///
9540	/// \param SS An optional C++ scope-specifier.
9541	///
9542	/// \returns true if lookup succeeded, false if it failed.
9543	bool LookupQualifiedName(LookupResult &R, DeclContext *LookupCtx,
9544	CXXScopeSpec &SS);
9545
9546	/// Performs name lookup for a name that was parsed in the
9547	/// source code, and may contain a C++ scope specifier.
9548	///
9549	/// This routine is a convenience routine meant to be called from
9550	/// contexts that receive a name and an optional C++ scope specifier
9551	/// (e.g., "N::M::x"). It will then perform either qualified or
9552	/// unqualified name lookup (with LookupQualifiedName or LookupName,
9553	/// respectively) on the given name and return those results. It will
9554	/// perform a special type of lookup for "__super::" scope specifier.
9555	///
9556	/// @param S The scope from which unqualified name lookup will
9557	/// begin.
9558	///
9559	/// @param SS An optional C++ scope-specifier, e.g., "::N::M".
9560	///
9561	/// @param EnteringContext Indicates whether we are going to enter the
9562	/// context of the scope-specifier SS (if present).
9563	///
9564	/// @returns True if any decls were found (but possibly ambiguous)
9565	bool LookupParsedName(LookupResult &R, Scope S, CXXScopeSpec SS,
9566	QualType ObjectType, bool AllowBuiltinCreation = false,
9567	bool EnteringContext = false);
9568
9569	/// Perform qualified name lookup into all base classes of the given
9570	/// class.
9571	///
9572	/// \param R captures both the lookup criteria and any lookup results found.
9573	///
9574	/// \param Class The context in which qualified name lookup will
9575	/// search. Name lookup will search in all base classes merging the results.
9576	///
9577	/// @returns True if any decls were found (but possibly ambiguous)
9578	bool LookupInSuper(LookupResult &R, CXXRecordDecl *Class);
9579
9580	void LookupOverloadedOperatorName(OverloadedOperatorKind Op, Scope *S,
9581	UnresolvedSetImpl &Functions);
9582
9583	/// LookupOrCreateLabel - Do a name lookup of a label with the specified name.
9584	/// If GnuLabelLoc is a valid source location, then this is a definition
9585	/// of an __label__ label name, otherwise it is a normal label definition
9586	/// or use.
9587	LabelDecl LookupOrCreateLabel(IdentifierInfo II, SourceLocation IdentLoc,
9588	SourceLocation GnuLabelLoc = SourceLocation ());
9589
9590	/// Perform a name lookup for a label with the specified name; this does not
9591	/// create a new label if the lookup fails.
9592	LabelDecl LookupExistingLabel(IdentifierInfo II, SourceLocation IdentLoc);
9593
9594	/// Look up the constructors for the given class.
9595	DeclContextLookupResult LookupConstructors(CXXRecordDecl *Class);
9596
9597	/// Look up the default constructor for the given class.
9598	CXXConstructorDecl LookupDefaultConstructor(CXXRecordDecl Class);
9599
9600	/// Look up the copying constructor for the given class.
9601	CXXConstructorDecl LookupCopyingConstructor(CXXRecordDecl Class,
9602	unsigned Quals);
9603
9604	/// Look up the copying assignment operator for the given class.
9605	CXXMethodDecl LookupCopyingAssignment(CXXRecordDecl Class, unsigned Quals,
9606	bool RValueThis, unsigned ThisQuals);
9607
9608	/// Look up the moving constructor for the given class.
9609	CXXConstructorDecl LookupMovingConstructor(CXXRecordDecl Class,
9610	unsigned Quals);
9611
9612	/// Look up the moving assignment operator for the given class.
9613	CXXMethodDecl LookupMovingAssignment(CXXRecordDecl Class, unsigned Quals,
9614	bool RValueThis, unsigned ThisQuals);
9615
9616	/// Look for the destructor of the given class.
9617	///
9618	/// During semantic analysis, this routine should be used in lieu of
9619	/// CXXRecordDecl::getDestructor().
9620	///
9621	/// \returns The destructor for this class.
9622	CXXDestructorDecl LookupDestructor(CXXRecordDecl Class);
9623
9624	/// Force the declaration of any implicitly-declared members of this
9625	/// class.
9626	void ForceDeclarationOfImplicitMembers(CXXRecordDecl *Class);
9627
9628	/// Make a merged definition of an existing hidden definition \p ND
9629	/// visible at the specified location.
9630	void makeMergedDefinitionVisible(NamedDecl *ND);
9631
9632	/// Check ODR hashes for C/ObjC when merging types from modules.
9633	/// Differently from C++, actually parse the body and reject in case
9634	/// of a mismatch.
9635	template <typename T,
9636	typename = std::enable_if_t<std::is_base_of<NamedDecl, T>::value>>
9637	bool ActOnDuplicateODRHashDefinition(T Duplicate, T Previous) {
9638	if (Duplicate->getODRHash() != Previous->getODRHash())
9639	return false;
9640
9641	// Make the previous decl visible.
9642	makeMergedDefinitionVisible(ND: Previous);
9643	return true;
9644	}
9645
9646	/// Get the set of additional modules that should be checked during
9647	/// name lookup. A module and its imports become visible when instanting a
9648	/// template defined within it.
9649	llvm::DenseSet<Module *> &getLookupModules();
9650
9651	bool hasVisibleMergedDefinition(const NamedDecl *Def);
9652	bool hasMergedDefinitionInCurrentModule(const NamedDecl *Def);
9653
9654	/// Determine if the template parameter \p D has a visible default argument.
9655	bool
9656	hasVisibleDefaultArgument(const NamedDecl *D,
9657	llvm::SmallVectorImpl<Module > Modules = nullptr);
9658	/// Determine if the template parameter \p D has a reachable default argument.
9659	bool hasReachableDefaultArgument(
9660	const NamedDecl D, llvm::SmallVectorImpl<Module > Modules = nullptr*);
9661	/// Determine if the template parameter \p D has a reachable default argument.
9662	bool hasAcceptableDefaultArgument(const NamedDecl *D,
9663	llvm::SmallVectorImpl<Module > Modules,
9664	Sema::AcceptableKind Kind);
9665
9666	/// Determine if there is a visible declaration of \p D that is an explicit
9667	/// specialization declaration for a specialization of a template. (For a
9668	/// member specialization, use hasVisibleMemberSpecialization.)
9669	bool hasVisibleExplicitSpecialization(
9670	const NamedDecl D, llvm::SmallVectorImpl<Module > Modules = nullptr*);
9671	/// Determine if there is a reachable declaration of \p D that is an explicit
9672	/// specialization declaration for a specialization of a template. (For a
9673	/// member specialization, use hasReachableMemberSpecialization.)
9674	bool hasReachableExplicitSpecialization(
9675	const NamedDecl D, llvm::SmallVectorImpl<Module > Modules = nullptr*);
9676
9677	/// Determine if there is a visible declaration of \p D that is a member
9678	/// specialization declaration (as opposed to an instantiated declaration).
9679	bool hasVisibleMemberSpecialization(
9680	const NamedDecl D, llvm::SmallVectorImpl<Module > Modules = nullptr*);
9681	/// Determine if there is a reachable declaration of \p D that is a member
9682	/// specialization declaration (as opposed to an instantiated declaration).
9683	bool hasReachableMemberSpecialization(
9684	const NamedDecl D, llvm::SmallVectorImpl<Module > Modules = nullptr*);
9685
9686	bool isModuleVisible(const Module M, bool* ModulePrivate = false);
9687
9688	/// Determine whether any declaration of an entity is visible.
9689	bool
9690	hasVisibleDeclaration(const NamedDecl *D,
9691	llvm::SmallVectorImpl<Module > Modules = nullptr) {
9692	return isVisible(D) \|\| hasVisibleDeclarationSlow(D, Modules);
9693	}
9694
9695	bool hasVisibleDeclarationSlow(const NamedDecl *D,
9696	llvm::SmallVectorImpl<Module > Modules);
9697	/// Determine whether any declaration of an entity is reachable.
9698	bool
9699	hasReachableDeclaration(const NamedDecl *D,
9700	llvm::SmallVectorImpl<Module > Modules = nullptr) {
9701	return isReachable(D) \|\| hasReachableDeclarationSlow(D, Modules);
9702	}
9703	bool hasReachableDeclarationSlow(
9704	const NamedDecl D, llvm::SmallVectorImpl<Module > Modules = nullptr*);
9705
9706	void diagnoseTypo(const TypoCorrection &Correction,
9707	const PartialDiagnostic &TypoDiag,
9708	bool ErrorRecovery = true);
9709
9710	/// Diagnose a successfully-corrected typo. Separated from the correction
9711	/// itself to allow external validation of the result, etc.
9712	///
9713	/// \param Correction The result of performing typo correction.
9714	/// \param TypoDiag The diagnostic to produce. This will have the corrected
9715	/// string added to it (and usually also a fixit).
9716	/// \param PrevNote A note to use when indicating the location of the entity
9717	/// to which we are correcting. Will have the correction string added
9718	/// to it.
9719	/// \param ErrorRecovery If \c true (the default), the caller is going to
9720	/// recover from the typo as if the corrected string had been typed.
9721	/// In this case, \c PDiag must be an error, and we will attach a fixit
9722	/// to it.
9723	void diagnoseTypo(const TypoCorrection &Correction,
9724	const PartialDiagnostic &TypoDiag,
9725	const PartialDiagnostic &PrevNote,
9726	bool ErrorRecovery = true);
9727
9728	/// Find the associated classes and namespaces for
9729	/// argument-dependent lookup for a call with the given set of
9730	/// arguments.
9731	///
9732	/// This routine computes the sets of associated classes and associated
9733	/// namespaces searched by argument-dependent lookup
9734	/// (C++ [basic.lookup.argdep]) for a given set of arguments.
9735	void FindAssociatedClassesAndNamespaces(
9736	SourceLocation InstantiationLoc, ArrayRef<Expr *> Args,
9737	AssociatedNamespaceSet &AssociatedNamespaces,
9738	AssociatedClassSet &AssociatedClasses);
9739
9740	/// Produce a diagnostic describing the ambiguity that resulted
9741	/// from name lookup.
9742	///
9743	/// \param Result The result of the ambiguous lookup to be diagnosed.
9744	void DiagnoseAmbiguousLookup(LookupResult &Result);
9745
9746	/// LookupLiteralOperator - Determine which literal operator should be used
9747	/// for a user-defined literal, per C++11 [lex.ext].
9748	///
9749	/// Normal overload resolution is not used to select which literal operator to
9750	/// call for a user-defined literal. Look up the provided literal operator
9751	/// name, and filter the results to the appropriate set for the given argument
9752	/// types.
9753	LiteralOperatorLookupResult
9754	LookupLiteralOperator(Scope *S, LookupResult &R, ArrayRef<QualType> ArgTys,
9755	bool AllowRaw, bool AllowTemplate,
9756	bool AllowStringTemplate, bool DiagnoseMissing,
9757	StringLiteral StringLit = nullptr*);
9758
9759	void ArgumentDependentLookup(DeclarationName Name, SourceLocation Loc,
9760	ArrayRef<Expr *> Args, ADLResult &Functions);
9761
9762	void LookupVisibleDecls(Scope *S, LookupNameKind Kind,
9763	VisibleDeclConsumer &Consumer,
9764	bool IncludeGlobalScope = true,
9765	bool LoadExternal = true);
9766	void LookupVisibleDecls(DeclContext *Ctx, LookupNameKind Kind,
9767	VisibleDeclConsumer &Consumer,
9768	bool IncludeGlobalScope = true,
9769	bool IncludeDependentBases = false,
9770	bool LoadExternal = true);
9771
9772	/// Try to "correct" a typo in the source code by finding
9773	/// visible declarations whose names are similar to the name that was
9774	/// present in the source code.
9775	///
9776	/// \param TypoName the \c DeclarationNameInfo structure that contains
9777	/// the name that was present in the source code along with its location.
9778	///
9779	/// \param LookupKind the name-lookup criteria used to search for the name.
9780	///
9781	/// \param S the scope in which name lookup occurs.
9782	///
9783	/// \param SS the nested-name-specifier that precedes the name we're
9784	/// looking for, if present.
9785	///
9786	/// \param CCC A CorrectionCandidateCallback object that provides further
9787	/// validation of typo correction candidates. It also provides flags for
9788	/// determining the set of keywords permitted.
9789	///
9790	/// \param MemberContext if non-NULL, the context in which to look for
9791	/// a member access expression.
9792	///
9793	/// \param EnteringContext whether we're entering the context described by
9794	/// the nested-name-specifier SS.
9795	///
9796	/// \param OPT when non-NULL, the search for visible declarations will
9797	/// also walk the protocols in the qualified interfaces of \p OPT.
9798	///
9799	/// \returns a \c TypoCorrection containing the corrected name if the typo
9800	/// along with information such as the \c NamedDecl where the corrected name
9801	/// was declared, and any additional \c NestedNameSpecifier needed to access
9802	/// it (C++ only). The \c TypoCorrection is empty if there is no correction.
9803	TypoCorrection CorrectTypo(const DeclarationNameInfo &Typo,
9804	Sema::LookupNameKind LookupKind, Scope *S,
9805	CXXScopeSpec *SS, CorrectionCandidateCallback &CCC,
9806	CorrectTypoKind Mode,
9807	DeclContext MemberContext = nullptr*,
9808	bool EnteringContext = false,
9809	const ObjCObjectPointerType OPT = nullptr*,
9810	bool RecordFailure = true);
9811
9812	/// Kinds of missing import. Note, the values of these enumerators correspond
9813	/// to %select values in diagnostics.
9814	enum class MissingImportKind {
9815	Declaration,
9816	Definition,
9817	DefaultArgument,
9818	ExplicitSpecialization,
9819	PartialSpecialization
9820	};
9821
9822	/// Diagnose that the specified declaration needs to be visible but
9823	/// isn't, and suggest a module import that would resolve the problem.
9824	void diagnoseMissingImport(SourceLocation Loc, const NamedDecl *Decl,
9825	MissingImportKind MIK, bool Recover = true);
9826	void diagnoseMissingImport(SourceLocation Loc, const NamedDecl *Decl,
9827	SourceLocation DeclLoc, ArrayRef<Module *> Modules,
9828	MissingImportKind MIK, bool Recover);
9829
9830	/// Called on #pragma clang __debug dump II
9831	void ActOnPragmaDump(Scope S, SourceLocation Loc, IdentifierInfo II);
9832
9833	/// Called on #pragma clang __debug dump E
9834	void ActOnPragmaDump(Expr *E);
9835
9836	private:
9837	// The set of known/encountered (unique, canonicalized) NamespaceDecls.
9838	//
9839	// The boolean value will be true to indicate that the namespace was loaded
9840	// from an AST/PCH file, or false otherwise.
9841	llvm::MapVector<NamespaceDecl , bool*> KnownNamespaces;
9842
9843	/// Whether we have already loaded known namespaces from an extenal
9844	/// source.
9845	bool LoadedExternalKnownNamespaces;
9846
9847	bool CppLookupName(LookupResult &R, Scope *S);
9848
9849	/// Determine if we could use all the declarations in the module.
9850	bool isUsableModule(const Module *M);
9851
9852	/// Helper for CorrectTypo used to create and populate a new
9853	/// TypoCorrectionConsumer. Returns nullptr if typo correction should be
9854	/// skipped entirely.
9855	std::unique_ptr<TypoCorrectionConsumer> makeTypoCorrectionConsumer(
9856	const DeclarationNameInfo &Typo, Sema::LookupNameKind LookupKind,
9857	Scope S, CXXScopeSpec SS, CorrectionCandidateCallback &CCC,
9858	DeclContext MemberContext, bool* EnteringContext,
9859	const ObjCObjectPointerType OPT, bool* ErrorRecovery);
9860
9861	/// Cache for module units which is usable for current module.
9862	llvm::DenseSet<const Module *> UsableModuleUnitsCache;
9863
9864	/// Record the typo correction failure and return an empty correction.
9865	TypoCorrection FailedCorrection(IdentifierInfo *Typo, SourceLocation TypoLoc,
9866	bool RecordFailure = true) {
9867	if (RecordFailure)
9868	TypoCorrectionFailures [Typo].insert(V: TypoLoc);
9869	return TypoCorrection ();
9870	}
9871
9872	bool isAcceptableSlow(const NamedDecl *D, AcceptableKind Kind);
9873
9874	/// Determine whether two declarations should be linked together, given that
9875	/// the old declaration might not be visible and the new declaration might
9876	/// not have external linkage.
9877	bool shouldLinkPossiblyHiddenDecl(const NamedDecl *Old,
9878	const NamedDecl *New) {
9879	if (isVisible(D: Old))
9880	return true;
9881	// See comment in below overload for why it's safe to compute the linkage
9882	// of the new declaration here.
9883	if (New->isExternallyDeclarable()) {
9884	assert(Old->isExternallyDeclarable() &&
9885	"should not have found a non-externally-declarable previous decl");
9886	return true;
9887	}
9888	return false;
9889	}
9890	bool shouldLinkPossiblyHiddenDecl(LookupResult &Old, const NamedDecl *New);
9891
9892	///@}
9893
9894	//
9895	//
9896	// -------------------------------------------------------------------------
9897	//
9898	//
9899
9900	/// \name Modules
9901	/// Implementations are in SemaModule.cpp
9902	///@{
9903
9904	public:
9905	/// Get the module unit whose scope we are currently within.
9906	Module getCurrentModule() const* {
9907	return ModuleScopes.empty() ? nullptr : ModuleScopes.back().Module;
9908	}
9909
9910	/// Is the module scope we are an implementation unit?
9911	bool currentModuleIsImplementation() const {
9912	return ModuleScopes.empty()
9913	? false
9914	: ModuleScopes.back().Module->isModuleImplementation();
9915	}
9916
9917	// When loading a non-modular PCH files, this is used to restore module
9918	// visibility.
9919	void makeModuleVisible(Module *Mod, SourceLocation ImportLoc) {
9920	VisibleModules.setVisible(M: Mod, Loc: ImportLoc);
9921	}
9922
9923	enum class ModuleDeclKind {
9924	Interface, ///< 'export module X;'
9925	Implementation, ///< 'module X;'
9926	PartitionInterface, ///< 'export module X:Y;'
9927	PartitionImplementation, ///< 'module X:Y;'
9928	};
9929
9930	/// An enumeration to represent the transition of states in parsing module
9931	/// fragments and imports. If we are not parsing a C++20 TU, or we find
9932	/// an error in state transition, the state is set to NotACXX20Module.
9933	enum class ModuleImportState {
9934	FirstDecl, ///< Parsing the first decl in a TU.
9935	GlobalFragment, ///< after 'module;' but before 'module X;'
9936	ImportAllowed, ///< after 'module X;' but before any non-import decl.
9937	ImportFinished, ///< after any non-import decl.
9938	PrivateFragmentImportAllowed, ///< after 'module :private;' but before any
9939	///< non-import decl.
9940	PrivateFragmentImportFinished, ///< after 'module :private;' but a
9941	///< non-import decl has already been seen.
9942	NotACXX20Module ///< Not a C++20 TU, or an invalid state was found.
9943	};
9944
9945	/// The parser has processed a module-declaration that begins the definition
9946	/// of a module interface or implementation.
9947	DeclGroupPtrTy ActOnModuleDecl(SourceLocation StartLoc,
9948	SourceLocation ModuleLoc, ModuleDeclKind MDK,
9949	ModuleIdPath Path, ModuleIdPath Partition,
9950	ModuleImportState &ImportState,
9951	bool SeenNoTrivialPPDirective);
9952
9953	/// The parser has processed a global-module-fragment declaration that begins
9954	/// the definition of the global module fragment of the current module unit.
9955	/// \param ModuleLoc The location of the 'module' keyword.
9956	DeclGroupPtrTy ActOnGlobalModuleFragmentDecl(SourceLocation ModuleLoc);
9957
9958	/// The parser has processed a private-module-fragment declaration that begins
9959	/// the definition of the private module fragment of the current module unit.
9960	/// \param ModuleLoc The location of the 'module' keyword.
9961	/// \param PrivateLoc The location of the 'private' keyword.
9962	DeclGroupPtrTy ActOnPrivateModuleFragmentDecl(SourceLocation ModuleLoc,
9963	SourceLocation PrivateLoc);
9964
9965	/// The parser has processed a module import declaration.
9966	///
9967	/// \param StartLoc The location of the first token in the declaration. This
9968	/// could be the location of an '@', 'export', or 'import'.
9969	/// \param ExportLoc The location of the 'export' keyword, if any.
9970	/// \param ImportLoc The location of the 'import' keyword.
9971	/// \param Path The module toplevel name as an access path.
9972	/// \param IsPartition If the name is for a partition.
9973	DeclResult ActOnModuleImport(SourceLocation StartLoc,
9974	SourceLocation ExportLoc,
9975	SourceLocation ImportLoc, ModuleIdPath Path,
9976	bool IsPartition = false);
9977	DeclResult ActOnModuleImport(SourceLocation StartLoc,
9978	SourceLocation ExportLoc,
9979	SourceLocation ImportLoc, Module *M,
9980	ModuleIdPath Path = {});
9981
9982	/// The parser has processed a module import translated from a
9983	/// #include or similar preprocessing directive.
9984	void ActOnAnnotModuleInclude(SourceLocation DirectiveLoc, Module *Mod);
9985	void BuildModuleInclude(SourceLocation DirectiveLoc, Module *Mod);
9986
9987	/// The parsed has entered a submodule.
9988	void ActOnAnnotModuleBegin(SourceLocation DirectiveLoc, Module *Mod);
9989	/// The parser has left a submodule.
9990	void ActOnAnnotModuleEnd(SourceLocation DirectiveLoc, Module *Mod);
9991
9992	/// Create an implicit import of the given module at the given
9993	/// source location, for error recovery, if possible.
9994	///
9995	/// This routine is typically used when an entity found by name lookup
9996	/// is actually hidden within a module that we know about but the user
9997	/// has forgotten to import.
9998	void createImplicitModuleImportForErrorRecovery(SourceLocation Loc,
9999	Module *Mod);
10000
10001	/// We have parsed the start of an export declaration, including the '{'
10002	/// (if present).
10003	Decl ActOnStartExportDecl(Scope S, SourceLocation ExportLoc,
10004	SourceLocation LBraceLoc);
10005
10006	/// Complete the definition of an export declaration.
10007	Decl ActOnFinishExportDecl(Scope S, Decl *ExportDecl,
10008	SourceLocation RBraceLoc);
10009
10010	private:
10011	/// The parser has begun a translation unit to be compiled as a C++20
10012	/// Header Unit, helper for ActOnStartOfTranslationUnit() only.
10013	void HandleStartOfHeaderUnit();
10014
10015	struct ModuleScope {
10016	SourceLocation BeginLoc;
10017	clang::Module Module = nullptr*;
10018	VisibleModuleSet OuterVisibleModules;
10019	};
10020	/// The modules we're currently parsing.
10021	llvm::SmallVector<ModuleScope, `16`> ModuleScopes;
10022
10023	/// For an interface unit, this is the implicitly imported interface unit.
10024	clang::Module ThePrimaryInterface = nullptr*;
10025
10026	/// The explicit global module fragment of the current translation unit.
10027	/// The explicit Global Module Fragment, as specified in C++
10028	/// [module.global.frag].
10029	clang::Module TheGlobalModuleFragment = nullptr*;
10030
10031	/// The implicit global module fragments of the current translation unit.
10032	///
10033	/// The contents in the implicit global module fragment can't be discarded.
10034	clang::Module TheImplicitGlobalModuleFragment = nullptr*;
10035
10036	/// Namespace definitions that we will export when they finish.
10037	llvm::SmallPtrSet<const NamespaceDecl *, `8`> DeferredExportedNamespaces;
10038
10039	/// In a C++ standard module, inline declarations require a definition to be
10040	/// present at the end of a definition domain. This set holds the decls to
10041	/// be checked at the end of the TU.
10042	llvm::SmallPtrSet<const FunctionDecl *, `8`> PendingInlineFuncDecls;
10043
10044	/// Helper function to judge if we are in module purview.
10045	/// Return false if we are not in a module.
10046	bool isCurrentModulePurview() const;
10047
10048	/// Enter the scope of the explicit global module fragment.
10049	Module *PushGlobalModuleFragment(SourceLocation BeginLoc);
10050	/// Leave the scope of the explicit global module fragment.
10051	void PopGlobalModuleFragment();
10052
10053	/// Enter the scope of an implicit global module fragment.
10054	Module *PushImplicitGlobalModuleFragment(SourceLocation BeginLoc);
10055	/// Leave the scope of an implicit global module fragment.
10056	void PopImplicitGlobalModuleFragment();
10057
10058	VisibleModuleSet VisibleModules;
10059
10060	/// Whether we had imported any named modules.
10061	bool HadImportedNamedModules = false;
10062	/// The set of instantiations we need to check if they references TU-local
10063	/// entity from TUs. This only makes sense if we imported any named modules.
10064	llvm::SmallVector<std::pair<FunctionDecl *, SourceLocation>>
10065	PendingCheckReferenceForTULocal;
10066	/// Implement [basic.link]p18, which requires that we can't use TU-local
10067	/// entities from other TUs (ignoring header units).
10068	void checkReferenceToTULocalFromOtherTU(FunctionDecl *FD,
10069	SourceLocation PointOfInstantiation);
10070	/// Implement [basic.link]p17, which diagnose for non TU local exposure in
10071	/// module interface or module partition.
10072	void checkExposure(const TranslationUnitDecl *TU);
10073
10074	///@}
10075
10076	//
10077	//
10078	// -------------------------------------------------------------------------
10079	//
10080	//
10081
10082	/// \name C++ Overloading
10083	/// Implementations are in SemaOverload.cpp
10084	///@{
10085
10086	public:
10087	/// Whether deferrable diagnostics should be deferred.
10088	bool DeferDiags = false;
10089
10090	/// RAII class to control scope of DeferDiags.
10091	class DeferDiagsRAII {
10092	Sema &S;
10093	bool SavedDeferDiags = false;
10094
10095	public:
10096	DeferDiagsRAII(Sema &S, bool DeferDiags)
10097	: S(S), SavedDeferDiags(S.DeferDiags) {
10098	S.DeferDiags = SavedDeferDiags \|\| DeferDiags;
10099	}
10100	~DeferDiagsRAII() { S.DeferDiags = SavedDeferDiags; }
10101	DeferDiagsRAII(const DeferDiagsRAII &) = delete;
10102	DeferDiagsRAII &operator=(const DeferDiagsRAII &) = delete;
10103	};
10104
10105	/// Flag indicating if Sema is building a recovery call expression.
10106	///
10107	/// This flag is used to avoid building recovery call expressions
10108	/// if Sema is already doing so, which would cause infinite recursions.
10109	bool IsBuildingRecoveryCallExpr;
10110
10111	/// Determine whether the given New declaration is an overload of the
10112	/// declarations in Old. This routine returns OverloadKind::Match or
10113	/// OverloadKind::NonFunction if New and Old cannot be overloaded, e.g., if
10114	/// New has the same signature as some function in Old (C++ 1.3.10) or if the
10115	/// Old declarations aren't functions (or function templates) at all. When it
10116	/// does return OverloadKind::Match or OverloadKind::NonFunction, MatchedDecl
10117	/// will point to the decl that New cannot be overloaded with. This decl may
10118	/// be a UsingShadowDecl on top of the underlying declaration.
10119	///
10120	/// Example: Given the following input:
10121	///
10122	/// void f(int, float); // #1
10123	/// void f(int, int); // #2
10124	/// int f(int, int); // #3
10125	///
10126	/// When we process #1, there is no previous declaration of "f", so IsOverload
10127	/// will not be used.
10128	///
10129	/// When we process #2, Old contains only the FunctionDecl for #1. By
10130	/// comparing the parameter types, we see that #1 and #2 are overloaded (since
10131	/// they have different signatures), so this routine returns
10132	/// OverloadKind::Overload; MatchedDecl is unchanged.
10133	///
10134	/// When we process #3, Old is an overload set containing #1 and #2. We
10135	/// compare the signatures of #3 to #1 (they're overloaded, so we do nothing)
10136	/// and then #3 to #2. Since the signatures of #3 and #2 are identical (return
10137	/// types of functions are not part of the signature), IsOverload returns
10138	/// OverloadKind::Match and MatchedDecl will be set to point to the
10139	/// FunctionDecl for #2.
10140	///
10141	/// 'NewIsUsingShadowDecl' indicates that 'New' is being introduced into a
10142	/// class by a using declaration. The rules for whether to hide shadow
10143	/// declarations ignore some properties which otherwise figure into a function
10144	/// template's signature.
10145	OverloadKind CheckOverload(Scope S, FunctionDecl New,
10146	const LookupResult &OldDecls, NamedDecl *&OldDecl,
10147	bool UseMemberUsingDeclRules);
10148	bool IsOverload(FunctionDecl New, FunctionDecl Old,
10149	bool UseMemberUsingDeclRules, bool ConsiderCudaAttrs = true);
10150
10151	// Checks whether MD constitutes an override the base class method BaseMD.
10152	// When checking for overrides, the object object members are ignored.
10153	bool IsOverride(FunctionDecl MD, FunctionDecl BaseMD,
10154	bool UseMemberUsingDeclRules, bool ConsiderCudaAttrs = true);
10155
10156	enum class AllowedExplicit {
10157	/// Allow no explicit functions to be used.
10158	None,
10159	/// Allow explicit conversion functions but not explicit constructors.
10160	Conversions,
10161	/// Allow both explicit conversion functions and explicit constructors.
10162	All
10163	};
10164
10165	ImplicitConversionSequence TryImplicitConversion(
10166	Expr From, QualType ToType, bool* SuppressUserConversions,
10167	AllowedExplicit AllowExplicit, bool InOverloadResolution, bool CStyle,
10168	bool AllowObjCWritebackConversion);
10169
10170	/// PerformImplicitConversion - Perform an implicit conversion of the
10171	/// expression From to the type ToType. Returns the
10172	/// converted expression. Flavor is the kind of conversion we're
10173	/// performing, used in the error message. If @p AllowExplicit,
10174	/// explicit user-defined conversions are permitted.
10175	ExprResult PerformImplicitConversion(Expr *From, QualType ToType,
10176	AssignmentAction Action,
10177	bool AllowExplicit = false);
10178
10179	/// IsIntegralPromotion - Determines whether the conversion from the
10180	/// expression From (whose potentially-adjusted type is FromType) to
10181	/// ToType is an integral promotion (C++ 4.5). If so, returns true and
10182	/// sets PromotedType to the promoted type.
10183	bool IsIntegralPromotion(Expr *From, QualType FromType, QualType ToType);
10184
10185	/// IsFloatingPointPromotion - Determines whether the conversion from
10186	/// FromType to ToType is a floating point promotion (C++ 4.6). If so,
10187	/// returns true and sets PromotedType to the promoted type.
10188	bool IsFloatingPointPromotion(QualType FromType, QualType ToType);
10189
10190	/// Determine if a conversion is a complex promotion.
10191	///
10192	/// A complex promotion is defined as a complex -> complex conversion
10193	/// where the conversion between the underlying real types is a
10194	/// floating-point or integral promotion.
10195	bool IsComplexPromotion(QualType FromType, QualType ToType);
10196
10197	/// IsOverflowBehaviorTypePromotion - Determines whether the conversion from
10198	/// FromType to ToType involves an OverflowBehaviorType FromType being
10199	/// promoted to an OverflowBehaviorType ToType which has a larger bitwidth.
10200	/// If so, returns true and sets FromType to ToType.
10201	bool IsOverflowBehaviorTypePromotion(QualType FromType, QualType ToType);
10202
10203	/// IsOverflowBehaviorTypeConversion - Determines whether the conversion from
10204	/// FromType to ToType necessarily involves both an OverflowBehaviorType and
10205	/// a non-OverflowBehaviorType. If so, returns true and sets FromType to
10206	/// ToType.
10207	bool IsOverflowBehaviorTypeConversion(QualType FromType, QualType ToType);
10208
10209	/// IsPointerConversion - Determines whether the conversion of the
10210	/// expression From, which has the (possibly adjusted) type FromType,
10211	/// can be converted to the type ToType via a pointer conversion (C++
10212	/// 4.10). If so, returns true and places the converted type (that
10213	/// might differ from ToType in its cv-qualifiers at some level) into
10214	/// ConvertedType.
10215	///
10216	/// This routine also supports conversions to and from block pointers
10217	/// and conversions with Objective-C's 'id', 'id<protocols...>', and
10218	/// pointers to interfaces. FIXME: Once we've determined the
10219	/// appropriate overloading rules for Objective-C, we may want to
10220	/// split the Objective-C checks into a different routine; however,
10221	/// GCC seems to consider all of these conversions to be pointer
10222	/// conversions, so for now they live here. IncompatibleObjC will be
10223	/// set if the conversion is an allowed Objective-C conversion that
10224	/// should result in a warning.
10225	bool IsPointerConversion(Expr *From, QualType FromType, QualType ToType,
10226	bool InOverloadResolution, QualType &ConvertedType,
10227	bool &IncompatibleObjC);
10228
10229	/// isObjCPointerConversion - Determines whether this is an
10230	/// Objective-C pointer conversion. Subroutine of IsPointerConversion,
10231	/// with the same arguments and return values.
10232	bool isObjCPointerConversion(QualType FromType, QualType ToType,
10233	QualType &ConvertedType, bool &IncompatibleObjC);
10234	bool IsBlockPointerConversion(QualType FromType, QualType ToType,
10235	QualType &ConvertedType);
10236
10237	/// FunctionParamTypesAreEqual - This routine checks two function proto types
10238	/// for equality of their parameter types. Caller has already checked that
10239	/// they have same number of parameters. If the parameters are different,
10240	/// ArgPos will have the parameter index of the first different parameter.
10241	/// If `Reversed` is true, the parameters of `NewType` will be compared in
10242	/// reverse order. That's useful if one of the functions is being used as a
10243	/// C++20 synthesized operator overload with a reversed parameter order.
10244	bool FunctionParamTypesAreEqual(ArrayRef<QualType> Old,
10245	ArrayRef<QualType> New,
10246	unsigned ArgPos = nullptr*,
10247	bool Reversed = false);
10248
10249	bool FunctionParamTypesAreEqual(const FunctionProtoType *OldType,
10250	const FunctionProtoType *NewType,
10251	unsigned ArgPos = nullptr*,
10252	bool Reversed = false);
10253
10254	bool FunctionNonObjectParamTypesAreEqual(const FunctionDecl *OldFunction,
10255	const FunctionDecl *NewFunction,
10256	unsigned ArgPos = nullptr*,
10257	bool Reversed = false);
10258
10259	/// HandleFunctionTypeMismatch - Gives diagnostic information for differeing
10260	/// function types. Catches different number of parameter, mismatch in
10261	/// parameter types, and different return types.
10262	void HandleFunctionTypeMismatch(PartialDiagnostic &PDiag, QualType FromType,
10263	QualType ToType);
10264
10265	/// CheckPointerConversion - Check the pointer conversion from the
10266	/// expression From to the type ToType. This routine checks for
10267	/// ambiguous or inaccessible derived-to-base pointer
10268	/// conversions for which IsPointerConversion has already returned
10269	/// true. It returns true and produces a diagnostic if there was an
10270	/// error, or returns false otherwise.
10271	bool CheckPointerConversion(Expr *From, QualType ToType, CastKind &Kind,
10272	CXXCastPath &BasePath, bool IgnoreBaseAccess,
10273	bool Diagnose = true);
10274
10275	/// IsMemberPointerConversion - Determines whether the conversion of the
10276	/// expression From, which has the (possibly adjusted) type FromType, can be
10277	/// converted to the type ToType via a member pointer conversion (C++ 4.11).
10278	/// If so, returns true and places the converted type (that might differ from
10279	/// ToType in its cv-qualifiers at some level) into ConvertedType.
10280	bool IsMemberPointerConversion(Expr *From, QualType FromType, QualType ToType,
10281	bool InOverloadResolution,
10282	QualType &ConvertedType);
10283
10284	enum class MemberPointerConversionResult {
10285	Success,
10286	DifferentPointee,
10287	NotDerived,
10288	Ambiguous,
10289	Virtual,
10290	Inaccessible
10291	};
10292	enum class MemberPointerConversionDirection : bool { Downcast, Upcast };
10293	/// CheckMemberPointerConversion - Check the member pointer conversion from
10294	/// the expression From to the type ToType. This routine checks for ambiguous
10295	/// or virtual or inaccessible base-to-derived member pointer conversions for
10296	/// which IsMemberPointerConversion has already returned true. It produces a
10297	// diagnostic if there was an error.
10298	MemberPointerConversionResult CheckMemberPointerConversion(
10299	QualType FromType, const MemberPointerType *ToPtrType, CastKind &Kind,
10300	CXXCastPath &BasePath, SourceLocation CheckLoc, SourceRange OpRange,
10301	bool IgnoreBaseAccess, MemberPointerConversionDirection Direction);
10302
10303	/// IsQualificationConversion - Determines whether the conversion from
10304	/// an rvalue of type FromType to ToType is a qualification conversion
10305	/// (C++ 4.4).
10306	///
10307	/// \param ObjCLifetimeConversion Output parameter that will be set to
10308	/// indicate when the qualification conversion involves a change in the
10309	/// Objective-C object lifetime.
10310	bool IsQualificationConversion(QualType FromType, QualType ToType,
10311	bool CStyle, bool &ObjCLifetimeConversion);
10312
10313	/// Determine whether the conversion from FromType to ToType is a valid
10314	/// conversion of ExtInfo/ExtProtoInfo on the nested function type.
10315	/// More precisely, this method checks whether FromType can be transformed
10316	/// into an exact match for ToType, by transforming its extended function
10317	/// type information in legal manner (e.g. by strictly stripping "noreturn"
10318	/// or "noexcept", or by stripping "noescape" for arguments).
10319	bool IsFunctionConversion(QualType FromType, QualType ToType) const;
10320
10321	/// Same as `IsFunctionConversion`, but if this would return true, it sets
10322	/// `ResultTy` to `ToType`.
10323	bool TryFunctionConversion(QualType FromType, QualType ToType,
10324	QualType &ResultTy) const;
10325
10326	bool DiagnoseMultipleUserDefinedConversion(Expr *From, QualType ToType);
10327	void DiagnoseUseOfDeletedFunction(SourceLocation Loc, SourceRange Range,
10328	DeclarationName Name,
10329	OverloadCandidateSet &CandidateSet,
10330	FunctionDecl *Fn, MultiExprArg Args,
10331	bool IsMember = false);
10332
10333	ExprResult InitializeExplicitObjectArgument(Sema &S, Expr *Obj,
10334	FunctionDecl *Fun);
10335	ExprResult PerformImplicitObjectArgumentInitialization(
10336	Expr From, NestedNameSpecifier Qualifier, NamedDecl FoundDecl,
10337	CXXMethodDecl *Method);
10338
10339	/// PerformContextuallyConvertToBool - Perform a contextual conversion
10340	/// of the expression From to bool (C++0x [conv]p3).
10341	ExprResult PerformContextuallyConvertToBool(Expr *From);
10342
10343	/// PerformContextuallyConvertToObjCPointer - Perform a contextual
10344	/// conversion of the expression From to an Objective-C pointer type.
10345	/// Returns a valid but null ExprResult if no conversion sequence exists.
10346	ExprResult PerformContextuallyConvertToObjCPointer(Expr *From);
10347
10348	ExprResult BuildConvertedConstantExpression(Expr *From, QualType T,
10349	CCEKind CCE,
10350	NamedDecl Dest = nullptr*);
10351
10352	ExprResult CheckConvertedConstantExpression(Expr *From, QualType T,
10353	llvm::APSInt &Value, CCEKind CCE);
10354	ExprResult CheckConvertedConstantExpression(Expr *From, QualType T,
10355	APValue &Value, CCEKind CCE,
10356	NamedDecl Dest = nullptr*);
10357
10358	/// EvaluateConvertedConstantExpression - Evaluate an Expression
10359	/// That is a converted constant expression
10360	/// (which was built with BuildConvertedConstantExpression)
10361	ExprResult
10362	EvaluateConvertedConstantExpression(Expr *E, QualType T, APValue &Value,
10363	CCEKind CCE, bool RequireInt,
10364	const APValue &PreNarrowingValue);
10365
10366	/// Abstract base class used to perform a contextual implicit
10367	/// conversion from an expression to any type passing a filter.
10368	class ContextualImplicitConverter {
10369	public:
10370	bool Suppress;
10371	bool SuppressConversion;
10372
10373	ContextualImplicitConverter(bool Suppress = false,
10374	bool SuppressConversion = false)
10375	: Suppress(Suppress), SuppressConversion(SuppressConversion) {}
10376
10377	/// Determine whether the specified type is a valid destination type
10378	/// for this conversion.
10379	virtual bool match(QualType T) = `0`;
10380
10381	/// Emits a diagnostic complaining that the expression does not have
10382	/// integral or enumeration type.
10383	virtual SemaDiagnosticBuilder diagnoseNoMatch(Sema &S, SourceLocation Loc,
10384	QualType T) = `0`;
10385
10386	/// Emits a diagnostic when the expression has incomplete class type.
10387	virtual SemaDiagnosticBuilder
10388	diagnoseIncomplete(Sema &S, SourceLocation Loc, QualType T) = `0`;
10389
10390	/// Emits a diagnostic when the only matching conversion function
10391	/// is explicit.
10392	virtual SemaDiagnosticBuilder diagnoseExplicitConv(Sema &S,
10393	SourceLocation Loc,
10394	QualType T,
10395	QualType ConvTy) = `0`;
10396
10397	/// Emits a note for the explicit conversion function.
10398	virtual SemaDiagnosticBuilder
10399	noteExplicitConv(Sema &S, CXXConversionDecl *Conv, QualType ConvTy) = `0`;
10400
10401	/// Emits a diagnostic when there are multiple possible conversion
10402	/// functions.
10403	virtual SemaDiagnosticBuilder diagnoseAmbiguous(Sema &S, SourceLocation Loc,
10404	QualType T) = `0`;
10405
10406	/// Emits a note for one of the candidate conversions.
10407	virtual SemaDiagnosticBuilder
10408	noteAmbiguous(Sema &S, CXXConversionDecl *Conv, QualType ConvTy) = `0`;
10409
10410	/// Emits a diagnostic when we picked a conversion function
10411	/// (for cases when we are not allowed to pick a conversion function).
10412	virtual SemaDiagnosticBuilder diagnoseConversion(Sema &S,
10413	SourceLocation Loc,
10414	QualType T,
10415	QualType ConvTy) = `0`;
10416
10417	virtual ~ContextualImplicitConverter() {}
10418	};
10419
10420	class ICEConvertDiagnoser : public ContextualImplicitConverter {
10421	bool AllowScopedEnumerations;
10422
10423	public:
10424	ICEConvertDiagnoser(bool AllowScopedEnumerations, bool Suppress,
10425	bool SuppressConversion)
10426	: ContextualImplicitConverter (Suppress, SuppressConversion),
10427	AllowScopedEnumerations(AllowScopedEnumerations) {}
10428
10429	/// Match an integral or (possibly scoped) enumeration type.
10430	bool match(QualType T) override;
10431
10432	SemaDiagnosticBuilder diagnoseNoMatch(Sema &S, SourceLocation Loc,
10433	QualType T) override {
10434	return diagnoseNotInt(S, Loc, T);
10435	}
10436
10437	/// Emits a diagnostic complaining that the expression does not have
10438	/// integral or enumeration type.
10439	virtual SemaDiagnosticBuilder diagnoseNotInt(Sema &S, SourceLocation Loc,
10440	QualType T) = `0`;
10441	};
10442
10443	/// Perform a contextual implicit conversion.
10444	ExprResult
10445	PerformContextualImplicitConversion(SourceLocation Loc, Expr *FromE,
10446	ContextualImplicitConverter &Converter);
10447
10448	/// ReferenceCompareResult - Expresses the result of comparing two
10449	/// types (cv1 T1 and cv2 T2) to determine their compatibility for the
10450	/// purposes of initialization by reference (C++ [dcl.init.ref]p4).
10451	enum ReferenceCompareResult {
10452	/// Ref_Incompatible - The two types are incompatible, so direct
10453	/// reference binding is not possible.
10454	Ref_Incompatible = `0`,
10455	/// Ref_Related - The two types are reference-related, which means
10456	/// that their unqualified forms (T1 and T2) are either the same
10457	/// or T1 is a base class of T2.
10458	Ref_Related,
10459	/// Ref_Compatible - The two types are reference-compatible.
10460	Ref_Compatible
10461	};
10462
10463	// Fake up a scoped enumeration that still contextually converts to bool.
10464	struct ReferenceConversionsScope {
10465	/// The conversions that would be performed on an lvalue of type T2 when
10466	/// binding a reference of type T1 to it, as determined when evaluating
10467	/// whether T1 is reference-compatible with T2.
10468	enum ReferenceConversions {
10469	Qualification = `0x1`,
10470	NestedQualification = `0x2`,
10471	Function = `0x4`,
10472	DerivedToBase = `0x8`,
10473	ObjC = `0x10`,
10474	ObjCLifetime = `0x20`,
10475
10476	LLVM_MARK_AS_BITMASK_ENUM(/LargestValue=/ObjCLifetime)
10477	};
10478	};
10479	using ReferenceConversions = ReferenceConversionsScope::ReferenceConversions;
10480
10481	/// CompareReferenceRelationship - Compare the two types T1 and T2 to
10482	/// determine whether they are reference-compatible,
10483	/// reference-related, or incompatible, for use in C++ initialization by
10484	/// reference (C++ [dcl.ref.init]p4). Neither type can be a reference
10485	/// type, and the first type (T1) is the pointee type of the reference
10486	/// type being initialized.
10487	ReferenceCompareResult
10488	CompareReferenceRelationship(SourceLocation Loc, QualType T1, QualType T2,
10489	ReferenceConversions Conv = nullptr*);
10490
10491	/// AddOverloadCandidate - Adds the given function to the set of
10492	/// candidate functions, using the given function call arguments. If
10493	/// @p SuppressUserConversions, then don't allow user-defined
10494	/// conversions via constructors or conversion operators.
10495	///
10496	/// \param PartialOverloading true if we are performing "partial" overloading
10497	/// based on an incomplete set of function arguments. This feature is used by
10498	/// code completion.
10499	void AddOverloadCandidate(
10500	FunctionDecl Function, DeclAccessPair FoundDecl, ArrayRef<Expr > Args,
10501	OverloadCandidateSet &CandidateSet, bool SuppressUserConversions = false,
10502	bool PartialOverloading = false, bool AllowExplicit = true,
10503	bool AllowExplicitConversion = false,
10504	ADLCallKind IsADLCandidate = ADLCallKind::NotADL,
10505	ConversionSequenceList EarlyConversions = {},
10506	OverloadCandidateParamOrder PO = {},
10507	bool AggregateCandidateDeduction = false, bool StrictPackMatch = false);
10508
10509	/// Add all of the function declarations in the given function set to
10510	/// the overload candidate set.
10511	void AddFunctionCandidates(
10512	const UnresolvedSetImpl &Functions, ArrayRef<Expr *> Args,
10513	OverloadCandidateSet &CandidateSet,
10514	TemplateArgumentListInfo ExplicitTemplateArgs = nullptr*,
10515	bool SuppressUserConversions = false, bool PartialOverloading = false,
10516	bool FirstArgumentIsBase = false);
10517
10518	/// AddMethodCandidate - Adds a named decl (which is some kind of
10519	/// method) as a method candidate to the given overload set.
10520	void AddMethodCandidate(DeclAccessPair FoundDecl, QualType ObjectType,
10521	Expr::Classification ObjectClassification,
10522	ArrayRef<Expr *> Args,
10523	OverloadCandidateSet &CandidateSet,
10524	bool SuppressUserConversion = false,
10525	OverloadCandidateParamOrder PO = {});
10526
10527	/// AddMethodCandidate - Adds the given C++ member function to the set
10528	/// of candidate functions, using the given function call arguments
10529	/// and the object argument (@c Object). For example, in a call
10530	/// @c o.f(a1,a2), @c Object will contain @c o and @c Args will contain
10531	/// both @c a1 and @c a2. If @p SuppressUserConversions, then don't
10532	/// allow user-defined conversions via constructors or conversion
10533	/// operators.
10534	void AddMethodCandidate(CXXMethodDecl *Method, DeclAccessPair FoundDecl,
10535	CXXRecordDecl *ActingContext, QualType ObjectType,
10536	Expr::Classification ObjectClassification,
10537	ArrayRef<Expr *> Args,
10538	OverloadCandidateSet &CandidateSet,
10539	bool SuppressUserConversions = false,
10540	bool PartialOverloading = false,
10541	ConversionSequenceList EarlyConversions = {},
10542	OverloadCandidateParamOrder PO = {},
10543	bool StrictPackMatch = false);
10544
10545	/// Add a C++ member function template as a candidate to the candidate
10546	/// set, using template argument deduction to produce an appropriate member
10547	/// function template specialization.
10548	void AddMethodTemplateCandidate(
10549	FunctionTemplateDecl *MethodTmpl, DeclAccessPair FoundDecl,
10550	CXXRecordDecl *ActingContext,
10551	TemplateArgumentListInfo *ExplicitTemplateArgs, QualType ObjectType,
10552	Expr::Classification ObjectClassification, ArrayRef<Expr *> Args,
10553	OverloadCandidateSet &CandidateSet, bool SuppressUserConversions = false,
10554	bool PartialOverloading = false, OverloadCandidateParamOrder PO = {});
10555
10556	/// Add a C++ function template specialization as a candidate
10557	/// in the candidate set, using template argument deduction to produce
10558	/// an appropriate function template specialization.
10559	void AddTemplateOverloadCandidate(
10560	FunctionTemplateDecl *FunctionTemplate, DeclAccessPair FoundDecl,
10561	TemplateArgumentListInfo ExplicitTemplateArgs, ArrayRef<Expr > Args,
10562	OverloadCandidateSet &CandidateSet, bool SuppressUserConversions = false,
10563	bool PartialOverloading = false, bool AllowExplicit = true,
10564	ADLCallKind IsADLCandidate = ADLCallKind::NotADL,
10565	OverloadCandidateParamOrder PO = {},
10566	bool AggregateCandidateDeduction = false);
10567
10568	struct CheckNonDependentConversionsFlag {
10569	/// Do not consider any user-defined conversions when constructing the
10570	/// initializing sequence.
10571	bool SuppressUserConversions;
10572
10573	/// Before constructing the initializing sequence, we check whether the
10574	/// parameter type and argument type contain any user defined conversions.
10575	/// If so, do not initialize them. This effectively bypasses some undesired
10576	/// instantiation before checking constaints, which might otherwise result
10577	/// in non-SFINAE errors e.g. recursive constraints.
10578	bool OnlyInitializeNonUserDefinedConversions;
10579
10580	CheckNonDependentConversionsFlag(
10581	bool SuppressUserConversions,
10582	bool OnlyInitializeNonUserDefinedConversions)
10583	: SuppressUserConversions(SuppressUserConversions),
10584	OnlyInitializeNonUserDefinedConversions(
10585	OnlyInitializeNonUserDefinedConversions) {}
10586	};
10587
10588	/// Check that implicit conversion sequences can be formed for each argument
10589	/// whose corresponding parameter has a non-dependent type, per DR1391's
10590	/// [temp.deduct.call]p10.
10591	bool CheckNonDependentConversions(
10592	FunctionTemplateDecl *FunctionTemplate, ArrayRef<QualType> ParamTypes,
10593	ArrayRef<Expr *> Args, OverloadCandidateSet &CandidateSet,
10594	ConversionSequenceList &Conversions,
10595	CheckNonDependentConversionsFlag UserConversionFlag,
10596	CXXRecordDecl ActingContext = nullptr*, QualType ObjectType = QualType (),
10597	Expr::Classification ObjectClassification = {},
10598	OverloadCandidateParamOrder PO = {});
10599
10600	/// AddConversionCandidate - Add a C++ conversion function as a
10601	/// candidate in the candidate set (C++ [over.match.conv],
10602	/// C++ [over.match.copy]). From is the expression we're converting from,
10603	/// and ToType is the type that we're eventually trying to convert to
10604	/// (which may or may not be the same type as the type that the
10605	/// conversion function produces).
10606	void AddConversionCandidate(
10607	CXXConversionDecl *Conversion, DeclAccessPair FoundDecl,
10608	CXXRecordDecl ActingContext, Expr From, QualType ToType,
10609	OverloadCandidateSet &CandidateSet, bool AllowObjCConversionOnExplicit,
10610	bool AllowExplicit, bool AllowResultConversion = true,
10611	bool StrictPackMatch = false);
10612
10613	/// Adds a conversion function template specialization
10614	/// candidate to the overload set, using template argument deduction
10615	/// to deduce the template arguments of the conversion function
10616	/// template from the type that we are converting to (C++
10617	/// [temp.deduct.conv]).
10618	void AddTemplateConversionCandidate(
10619	FunctionTemplateDecl *FunctionTemplate, DeclAccessPair FoundDecl,
10620	CXXRecordDecl ActingContext, Expr From, QualType ToType,
10621	OverloadCandidateSet &CandidateSet, bool AllowObjCConversionOnExplicit,
10622	bool AllowExplicit, bool AllowResultConversion = true);
10623
10624	/// AddSurrogateCandidate - Adds a "surrogate" candidate function that
10625	/// converts the given @c Object to a function pointer via the
10626	/// conversion function @c Conversion, and then attempts to call it
10627	/// with the given arguments (C++ [over.call.object]p2-4). Proto is
10628	/// the type of function that we'll eventually be calling.
10629	void AddSurrogateCandidate(CXXConversionDecl *Conversion,
10630	DeclAccessPair FoundDecl,
10631	CXXRecordDecl *ActingContext,
10632	const FunctionProtoType Proto, Expr Object,
10633	ArrayRef<Expr *> Args,
10634	OverloadCandidateSet &CandidateSet);
10635
10636	/// Add all of the non-member operator function declarations in the given
10637	/// function set to the overload candidate set.
10638	void AddNonMemberOperatorCandidates(
10639	const UnresolvedSetImpl &Functions, ArrayRef<Expr *> Args,
10640	OverloadCandidateSet &CandidateSet,
10641	TemplateArgumentListInfo ExplicitTemplateArgs = nullptr*);
10642
10643	/// Add overload candidates for overloaded operators that are
10644	/// member functions.
10645	///
10646	/// Add the overloaded operator candidates that are member functions
10647	/// for the operator Op that was used in an operator expression such
10648	/// as "x Op y". , Args/NumArgs provides the operator arguments, and
10649	/// CandidateSet will store the added overload candidates. (C++
10650	/// [over.match.oper]).
10651	void AddMemberOperatorCandidates(OverloadedOperatorKind Op,
10652	SourceLocation OpLoc, ArrayRef<Expr *> Args,
10653	OverloadCandidateSet &CandidateSet,
10654	OverloadCandidateParamOrder PO = {});
10655
10656	/// AddBuiltinCandidate - Add a candidate for a built-in
10657	/// operator. ResultTy and ParamTys are the result and parameter types
10658	/// of the built-in candidate, respectively. Args and NumArgs are the
10659	/// arguments being passed to the candidate. IsAssignmentOperator
10660	/// should be true when this built-in candidate is an assignment
10661	/// operator. NumContextualBoolArguments is the number of arguments
10662	/// (at the beginning of the argument list) that will be contextually
10663	/// converted to bool.
10664	void AddBuiltinCandidate(QualType ParamTys, ArrayRef<Expr > Args,
10665	OverloadCandidateSet &CandidateSet,
10666	bool IsAssignmentOperator = false,
10667	unsigned NumContextualBoolArguments = `0`);
10668
10669	/// AddBuiltinOperatorCandidates - Add the appropriate built-in
10670	/// operator overloads to the candidate set (C++ [over.built]), based
10671	/// on the operator @p Op and the arguments given. For example, if the
10672	/// operator is a binary '+', this routine might add "int
10673	/// operator+(int, int)" to cover integer addition.
10674	void AddBuiltinOperatorCandidates(OverloadedOperatorKind Op,
10675	SourceLocation OpLoc, ArrayRef<Expr *> Args,
10676	OverloadCandidateSet &CandidateSet);
10677
10678	/// Add function candidates found via argument-dependent lookup
10679	/// to the set of overloading candidates.
10680	///
10681	/// This routine performs argument-dependent name lookup based on the
10682	/// given function name (which may also be an operator name) and adds
10683	/// all of the overload candidates found by ADL to the overload
10684	/// candidate set (C++ [basic.lookup.argdep]).
10685	void AddArgumentDependentLookupCandidates(
10686	DeclarationName Name, SourceLocation Loc, ArrayRef<Expr *> Args,
10687	TemplateArgumentListInfo *ExplicitTemplateArgs,
10688	OverloadCandidateSet &CandidateSet, bool PartialOverloading = false);
10689
10690	/// Check the enable_if expressions on the given function. Returns the first
10691	/// failing attribute, or NULL if they were all successful.
10692	EnableIfAttr CheckEnableIf(FunctionDecl Function, SourceLocation CallLoc,
10693	ArrayRef<Expr *> Args,
10694	bool MissingImplicitThis = false);
10695
10696	/// Emit diagnostics for the diagnose_if attributes on Function, ignoring any
10697	/// non-ArgDependent DiagnoseIfAttrs.
10698	///
10699	/// Argument-dependent diagnose_if attributes should be checked each time a
10700	/// function is used as a direct callee of a function call.
10701	///
10702	/// Returns true if any errors were emitted.
10703	bool diagnoseArgDependentDiagnoseIfAttrs(const FunctionDecl *Function,
10704	const Expr *ThisArg,
10705	ArrayRef<const Expr *> Args,
10706	SourceLocation Loc);
10707
10708	/// Emit diagnostics for the diagnose_if attributes on Function, ignoring any
10709	/// ArgDependent DiagnoseIfAttrs.
10710	///
10711	/// Argument-independent diagnose_if attributes should be checked on every use
10712	/// of a function.
10713	///
10714	/// Returns true if any errors were emitted.
10715	bool diagnoseArgIndependentDiagnoseIfAttrs(const NamedDecl *ND,
10716	SourceLocation Loc);
10717
10718	/// Determine if \p A and \p B are equivalent internal linkage declarations
10719	/// from different modules, and thus an ambiguity error can be downgraded to
10720	/// an extension warning.
10721	bool isEquivalentInternalLinkageDeclaration(const NamedDecl *A,
10722	const NamedDecl *B);
10723	void diagnoseEquivalentInternalLinkageDeclarations(
10724	SourceLocation Loc, const NamedDecl *D,
10725	ArrayRef<const NamedDecl *> Equiv);
10726
10727	// Emit as a 'note' the specific overload candidate
10728	void NoteOverloadCandidate(
10729	const NamedDecl Found, const* FunctionDecl *Fn,
10730	OverloadCandidateRewriteKind RewriteKind = OverloadCandidateRewriteKind(),
10731	QualType DestType = QualType (), bool TakingAddress = false);
10732
10733	// Emit as a series of 'note's all template and non-templates identified by
10734	// the expression Expr
10735	void NoteAllOverloadCandidates(Expr *E, QualType DestType = QualType (),
10736	bool TakingAddress = false);
10737
10738	/// Returns whether the given function's address can be taken or not,
10739	/// optionally emitting a diagnostic if the address can't be taken.
10740	///
10741	/// Returns false if taking the address of the function is illegal.
10742	bool checkAddressOfFunctionIsAvailable(const FunctionDecl *Function,
10743	bool Complain = false,
10744	SourceLocation Loc = SourceLocation ());
10745
10746	// [PossiblyAFunctionType] --> [Return]
10747	// NonFunctionType --> NonFunctionType
10748	// R (A) --> R(A)
10749	// R ()(A) --> R (A)*
10750	// R (&)(A) --> R (A)
10751	// R (S::)(A) --> R (A)*
10752	QualType ExtractUnqualifiedFunctionType(QualType PossiblyAFunctionType);
10753
10754	/// ResolveAddressOfOverloadedFunction - Try to resolve the address of
10755	/// an overloaded function (C++ [over.over]), where @p From is an
10756	/// expression with overloaded function type and @p ToType is the type
10757	/// we're trying to resolve to. For example:
10758	///
10759	/// @code
10760	/// int f(double);
10761	/// int f(int);
10762	///
10763	/// int (pfd)(double) = f; // selects f(double)*
10764	/// @endcode
10765	///
10766	/// This routine returns the resulting FunctionDecl if it could be
10767	/// resolved, and NULL otherwise. When @p Complain is true, this
10768	/// routine will emit diagnostics if there is an error.
10769	FunctionDecl *
10770	ResolveAddressOfOverloadedFunction(Expr *AddressOfExpr, QualType TargetType,
10771	bool Complain, DeclAccessPair &Found,
10772	bool pHadMultipleCandidates = nullptr*);
10773
10774	/// Given an expression that refers to an overloaded function, try to
10775	/// resolve that function to a single function that can have its address
10776	/// taken. This will modify `Pair` iff it returns non-null.
10777	///
10778	/// This routine can only succeed if from all of the candidates in the
10779	/// overload set for SrcExpr that can have their addresses taken, there is one
10780	/// candidate that is more constrained than the rest.
10781	FunctionDecl *
10782	resolveAddressOfSingleOverloadCandidate(Expr *E, DeclAccessPair &FoundResult);
10783
10784	/// Given an overloaded function, tries to turn it into a non-overloaded
10785	/// function reference using resolveAddressOfSingleOverloadCandidate. This
10786	/// will perform access checks, diagnose the use of the resultant decl, and,
10787	/// if requested, potentially perform a function-to-pointer decay.
10788	///
10789	/// Returns false if resolveAddressOfSingleOverloadCandidate fails.
10790	/// Otherwise, returns true. This may emit diagnostics and return true.
10791	bool resolveAndFixAddressOfSingleOverloadCandidate(
10792	ExprResult &SrcExpr, bool DoFunctionPointerConversion = false);
10793
10794	/// Given an expression that refers to an overloaded function, try to
10795	/// resolve that overloaded function expression down to a single function.
10796	///
10797	/// This routine can only resolve template-ids that refer to a single function
10798	/// template, where that template-id refers to a single template whose
10799	/// template arguments are either provided by the template-id or have
10800	/// defaults, as described in C++0x [temp.arg.explicit]p3.
10801	///
10802	/// If no template-ids are found, no diagnostics are emitted and NULL is
10803	/// returned.
10804	FunctionDecl *ResolveSingleFunctionTemplateSpecialization(
10805	OverloadExpr ovl, bool* Complain = false, DeclAccessPair Found = nullptr*,
10806	TemplateSpecCandidateSet FailedTSC = nullptr*,
10807	bool ForTypeDeduction = false);
10808
10809	// Resolve and fix an overloaded expression that can be resolved
10810	// because it identifies a single function template specialization.
10811	//
10812	// Last three arguments should only be supplied if Complain = true
10813	//
10814	// Return true if it was logically possible to so resolve the
10815	// expression, regardless of whether or not it succeeded. Always
10816	// returns true if 'complain' is set.
10817	bool ResolveAndFixSingleFunctionTemplateSpecialization(
10818	ExprResult &SrcExpr, bool DoFunctionPointerConversion = false,
10819	bool Complain = false, SourceRange OpRangeForComplaining = SourceRange (),
10820	QualType DestTypeForComplaining = QualType (),
10821	unsigned DiagIDForComplaining = `0`);
10822
10823	/// Add the overload candidates named by callee and/or found by argument
10824	/// dependent lookup to the given overload set.
10825	void AddOverloadedCallCandidates(UnresolvedLookupExpr *ULE,
10826	ArrayRef<Expr *> Args,
10827	OverloadCandidateSet &CandidateSet,
10828	bool PartialOverloading = false);
10829
10830	/// Add the call candidates from the given set of lookup results to the given
10831	/// overload set. Non-function lookup results are ignored.
10832	void AddOverloadedCallCandidates(
10833	LookupResult &R, TemplateArgumentListInfo *ExplicitTemplateArgs,
10834	ArrayRef<Expr *> Args, OverloadCandidateSet &CandidateSet);
10835
10836	// An enum used to represent the different possible results of building a
10837	// range-based for loop.
10838	enum ForRangeStatus {
10839	FRS_Success,
10840	FRS_NoViableFunction,
10841	FRS_DiagnosticIssued
10842	};
10843
10844	/// Build a call to 'begin' or 'end' for a C++11 for-range statement. If the
10845	/// given LookupResult is non-empty, it is assumed to describe a member which
10846	/// will be invoked. Otherwise, the function will be found via argument
10847	/// dependent lookup.
10848	/// CallExpr is set to a valid expression and FRS_Success returned on success,
10849	/// otherwise CallExpr is set to ExprError() and some non-success value
10850	/// is returned.
10851	ForRangeStatus BuildForRangeBeginEndCall(SourceLocation Loc,
10852	SourceLocation RangeLoc,
10853	const DeclarationNameInfo &NameInfo,
10854	LookupResult &MemberLookup,
10855	OverloadCandidateSet *CandidateSet,
10856	Expr Range, ExprResult CallExpr);
10857
10858	/// BuildOverloadedCallExpr - Given the call expression that calls Fn
10859	/// (which eventually refers to the declaration Func) and the call
10860	/// arguments Args/NumArgs, attempt to resolve the function call down
10861	/// to a specific function. If overload resolution succeeds, returns
10862	/// the call expression produced by overload resolution.
10863	/// Otherwise, emits diagnostics and returns ExprError.
10864	ExprResult BuildOverloadedCallExpr(
10865	Scope S, Expr Fn, UnresolvedLookupExpr *ULE, SourceLocation LParenLoc,
10866	MultiExprArg Args, SourceLocation RParenLoc, Expr *ExecConfig,
10867	bool AllowTypoCorrection = true, bool CalleesAddressIsTaken = false);
10868
10869	/// Constructs and populates an OverloadedCandidateSet from
10870	/// the given function.
10871	/// \returns true when an the ExprResult output parameter has been set.
10872	bool buildOverloadedCallSet(Scope S, Expr Fn, UnresolvedLookupExpr *ULE,
10873	MultiExprArg Args, SourceLocation RParenLoc,
10874	OverloadCandidateSet *CandidateSet,
10875	ExprResult *Result);
10876
10877	ExprResult CreateUnresolvedLookupExpr(CXXRecordDecl *NamingClass,
10878	NestedNameSpecifierLoc NNSLoc,
10879	DeclarationNameInfo DNI,
10880	const UnresolvedSetImpl &Fns,
10881	bool PerformADL = true);
10882
10883	/// Create a unary operation that may resolve to an overloaded
10884	/// operator.
10885	///
10886	/// \param OpLoc The location of the operator itself (e.g., '').*
10887	///
10888	/// \param Opc The UnaryOperatorKind that describes this operator.
10889	///
10890	/// \param Fns The set of non-member functions that will be
10891	/// considered by overload resolution. The caller needs to build this
10892	/// set based on the context using, e.g.,
10893	/// LookupOverloadedOperatorName() and ArgumentDependentLookup(). This
10894	/// set should not contain any member functions; those will be added
10895	/// by CreateOverloadedUnaryOp().
10896	///
10897	/// \param Input The input argument.
10898	ExprResult CreateOverloadedUnaryOp(SourceLocation OpLoc,
10899	UnaryOperatorKind Opc,
10900	const UnresolvedSetImpl &Fns, Expr *input,
10901	bool RequiresADL = true);
10902
10903	/// Perform lookup for an overloaded binary operator.
10904	void LookupOverloadedBinOp(OverloadCandidateSet &CandidateSet,
10905	OverloadedOperatorKind Op,
10906	const UnresolvedSetImpl &Fns,
10907	ArrayRef<Expr > Args, bool* RequiresADL = true);
10908
10909	/// Create a binary operation that may resolve to an overloaded
10910	/// operator.
10911	///
10912	/// \param OpLoc The location of the operator itself (e.g., '+').
10913	///
10914	/// \param Opc The BinaryOperatorKind that describes this operator.
10915	///
10916	/// \param Fns The set of non-member functions that will be
10917	/// considered by overload resolution. The caller needs to build this
10918	/// set based on the context using, e.g.,
10919	/// LookupOverloadedOperatorName() and ArgumentDependentLookup(). This
10920	/// set should not contain any member functions; those will be added
10921	/// by CreateOverloadedBinOp().
10922	///
10923	/// \param LHS Left-hand argument.
10924	/// \param RHS Right-hand argument.
10925	/// \param PerformADL Whether to consider operator candidates found by ADL.
10926	/// \param AllowRewrittenCandidates Whether to consider candidates found by
10927	/// C++20 operator rewrites.
10928	/// \param DefaultedFn If we are synthesizing a defaulted operator function,
10929	/// the function in question. Such a function is never a candidate in
10930	/// our overload resolution. This also enables synthesizing a three-way
10931	/// comparison from < and == as described in C++20 [class.spaceship]p1.
10932	ExprResult CreateOverloadedBinOp(SourceLocation OpLoc, BinaryOperatorKind Opc,
10933	const UnresolvedSetImpl &Fns, Expr *LHS,
10934	Expr RHS, bool* RequiresADL = true,
10935	bool AllowRewrittenCandidates = true,
10936	FunctionDecl DefaultedFn = nullptr*);
10937	ExprResult BuildSynthesizedThreeWayComparison(SourceLocation OpLoc,
10938	const UnresolvedSetImpl &Fns,
10939	Expr LHS, Expr RHS,
10940	FunctionDecl *DefaultedFn);
10941
10942	ExprResult CreateOverloadedArraySubscriptExpr(SourceLocation LLoc,
10943	SourceLocation RLoc, Expr *Base,
10944	MultiExprArg Args);
10945
10946	/// BuildCallToMemberFunction - Build a call to a member
10947	/// function. MemExpr is the expression that refers to the member
10948	/// function (and includes the object parameter), Args/NumArgs are the
10949	/// arguments to the function call (not including the object
10950	/// parameter). The caller needs to validate that the member
10951	/// expression refers to a non-static member function or an overloaded
10952	/// member function.
10953	ExprResult BuildCallToMemberFunction(
10954	Scope S, Expr MemExpr, SourceLocation LParenLoc, MultiExprArg Args,
10955	SourceLocation RParenLoc, Expr ExecConfig = nullptr*,
10956	bool IsExecConfig = false, bool AllowRecovery = false);
10957
10958	/// BuildCallToObjectOfClassType - Build a call to an object of class
10959	/// type (C++ [over.call.object]), which can end up invoking an
10960	/// overloaded function call operator (@c operator()) or performing a
10961	/// user-defined conversion on the object argument.
10962	ExprResult BuildCallToObjectOfClassType(Scope S, Expr Object,
10963	SourceLocation LParenLoc,
10964	MultiExprArg Args,
10965	SourceLocation RParenLoc);
10966
10967	/// BuildOverloadedArrowExpr - Build a call to an overloaded @c operator->
10968	/// (if one exists), where @c Base is an expression of class type and
10969	/// @c Member is the name of the member we're trying to find.
10970	ExprResult BuildOverloadedArrowExpr(Scope S, Expr Base,
10971	SourceLocation OpLoc,
10972	bool NoArrowOperatorFound = nullptr*);
10973
10974	ExprResult BuildCXXMemberCallExpr(Expr Exp, NamedDecl FoundDecl,
10975	CXXConversionDecl *Method,
10976	bool HadMultipleCandidates);
10977
10978	/// BuildLiteralOperatorCall - Build a UserDefinedLiteral by creating a call
10979	/// to a literal operator described by the provided lookup results.
10980	ExprResult BuildLiteralOperatorCall(
10981	LookupResult &R, DeclarationNameInfo &SuffixInfo, ArrayRef<Expr *> Args,
10982	SourceLocation LitEndLoc,
10983	TemplateArgumentListInfo ExplicitTemplateArgs = nullptr*);
10984
10985	/// FixOverloadedFunctionReference - E is an expression that refers to
10986	/// a C++ overloaded function (possibly with some parentheses and
10987	/// perhaps a '&' around it). We have resolved the overloaded function
10988	/// to the function declaration Fn, so patch up the expression E to
10989	/// refer (possibly indirectly) to Fn. Returns the new expr.
10990	ExprResult FixOverloadedFunctionReference(Expr *E, DeclAccessPair FoundDecl,
10991	FunctionDecl *Fn);
10992	ExprResult FixOverloadedFunctionReference(ExprResult,
10993	DeclAccessPair FoundDecl,
10994	FunctionDecl *Fn);
10995
10996	/// - Returns a selector which best matches given argument list or
10997	/// nullptr if none could be found
10998	ObjCMethodDecl *SelectBestMethod(Selector Sel, MultiExprArg Args,
10999	bool IsInstance,
11000	SmallVectorImpl<ObjCMethodDecl *> &Methods);
11001
11002	///@}
11003
11004	//
11005	//
11006	// -------------------------------------------------------------------------
11007	//
11008	//
11009
11010	/// \name Statements
11011	/// Implementations are in SemaStmt.cpp
11012	///@{
11013
11014	public:
11015	/// Stack of active SEH __finally scopes. Can be empty.
11016	SmallVector<Scope *, `2`> CurrentSEHFinally;
11017
11018	/// Stack of '_Defer' statements that are currently being parsed, as well
11019	/// as the locations of their '_Defer' keywords. Can be empty.
11020	SmallVector<std::pair<Scope *, SourceLocation>, `2`> CurrentDefer;
11021
11022	StmtResult ActOnExprStmt(ExprResult Arg, bool DiscardedValue = true);
11023	StmtResult ActOnExprStmtError();
11024
11025	StmtResult ActOnNullStmt(SourceLocation SemiLoc,
11026	bool HasLeadingEmptyMacro = false);
11027
11028	StmtResult ActOnDeclStmt(DeclGroupPtrTy Decl, SourceLocation StartLoc,
11029	SourceLocation EndLoc);
11030	void ActOnForEachDeclStmt(DeclGroupPtrTy Decl);
11031
11032	/// DiagnoseUnusedExprResult - If the statement passed in is an expression
11033	/// whose result is unused, warn.
11034	void DiagnoseUnusedExprResult(const Stmt S, unsigned* DiagID);
11035
11036	void ActOnStartOfCompoundStmt(bool IsStmtExpr);
11037	void ActOnAfterCompoundStatementLeadingPragmas();
11038	void ActOnFinishOfCompoundStmt();
11039	StmtResult ActOnCompoundStmt(SourceLocation L, SourceLocation R,
11040	ArrayRef<Stmt > Elts, bool* isStmtExpr);
11041
11042	sema::CompoundScopeInfo &getCurCompoundScope() const;
11043
11044	ExprResult ActOnCaseExpr(SourceLocation CaseLoc, ExprResult Val);
11045	StmtResult ActOnCaseStmt(SourceLocation CaseLoc, ExprResult LHS,
11046	SourceLocation DotDotDotLoc, ExprResult RHS,
11047	SourceLocation ColonLoc);
11048
11049	/// ActOnCaseStmtBody - This installs a statement as the body of a case.
11050	void ActOnCaseStmtBody(Stmt CaseStmt, Stmt SubStmt);
11051
11052	StmtResult ActOnDefaultStmt(SourceLocation DefaultLoc,
11053	SourceLocation ColonLoc, Stmt *SubStmt,
11054	Scope *CurScope);
11055	StmtResult ActOnLabelStmt(SourceLocation IdentLoc, LabelDecl *TheDecl,
11056	SourceLocation ColonLoc, Stmt *SubStmt);
11057
11058	StmtResult BuildAttributedStmt(SourceLocation AttrsLoc,
11059	ArrayRef<const Attr > Attrs, Stmt SubStmt);
11060	StmtResult ActOnAttributedStmt(const ParsedAttributes &AttrList,
11061	Stmt *SubStmt);
11062
11063	/// Check whether the given statement can have musttail applied to it,
11064	/// issuing a diagnostic and returning false if not. In the success case,
11065	/// the statement is rewritten to remove implicit nodes from the return
11066	/// value.
11067	bool checkAndRewriteMustTailAttr(Stmt St, const* Attr &MTA);
11068
11069	StmtResult ActOnIfStmt(SourceLocation IfLoc, IfStatementKind StatementKind,
11070	SourceLocation LParenLoc, Stmt *InitStmt,
11071	ConditionResult Cond, SourceLocation RParenLoc,
11072	Stmt ThenVal, SourceLocation ElseLoc, Stmt ElseVal);
11073	StmtResult BuildIfStmt(SourceLocation IfLoc, IfStatementKind StatementKind,
11074	SourceLocation LParenLoc, Stmt *InitStmt,
11075	ConditionResult Cond, SourceLocation RParenLoc,
11076	Stmt ThenVal, SourceLocation ElseLoc, Stmt ElseVal);
11077
11078	ExprResult CheckSwitchCondition(SourceLocation SwitchLoc, Expr *Cond);
11079
11080	StmtResult ActOnStartOfSwitchStmt(SourceLocation SwitchLoc,
11081	SourceLocation LParenLoc, Stmt *InitStmt,
11082	ConditionResult Cond,
11083	SourceLocation RParenLoc);
11084	StmtResult ActOnFinishSwitchStmt(SourceLocation SwitchLoc, Stmt *Switch,
11085	Stmt *Body);
11086
11087	/// DiagnoseAssignmentEnum - Warn if assignment to enum is a constant
11088	/// integer not in the range of enum values.
11089	void DiagnoseAssignmentEnum(QualType DstType, QualType SrcType,
11090	Expr *SrcExpr);
11091
11092	StmtResult ActOnWhileStmt(SourceLocation WhileLoc, SourceLocation LParenLoc,
11093	ConditionResult Cond, SourceLocation RParenLoc,
11094	Stmt *Body);
11095	StmtResult ActOnDoStmt(SourceLocation DoLoc, Stmt *Body,
11096	SourceLocation WhileLoc, SourceLocation CondLParen,
11097	Expr *Cond, SourceLocation CondRParen);
11098
11099	StmtResult ActOnForStmt(SourceLocation ForLoc, SourceLocation LParenLoc,
11100	Stmt *First, ConditionResult Second,
11101	FullExprArg Third, SourceLocation RParenLoc,
11102	Stmt *Body);
11103
11104	/// In an Objective C collection iteration statement:
11105	/// for (x in y)
11106	/// x can be an arbitrary l-value expression. Bind it up as a
11107	/// full-expression.
11108	StmtResult ActOnForEachLValueExpr(Expr *E);
11109
11110	enum BuildForRangeKind {
11111	/// Initial building of a for-range statement.
11112	BFRK_Build,
11113	/// Instantiation or recovery rebuild of a for-range statement. Don't
11114	/// attempt any typo-correction.
11115	BFRK_Rebuild,
11116	/// Determining whether a for-range statement could be built. Avoid any
11117	/// unnecessary or irreversible actions.
11118	BFRK_Check
11119	};
11120
11121	/// ActOnCXXForRangeStmt - Check and build a C++11 for-range statement.
11122	///
11123	/// C++11 [stmt.ranged]:
11124	/// A range-based for statement is equivalent to
11125	///
11126	/// {
11127	/// auto && __range = range-init;
11128	/// for ( auto __begin = begin-expr,
11129	/// __end = end-expr;
11130	/// __begin != __end;
11131	/// ++__begin ) {
11132	/// for-range-declaration = __begin;*
11133	/// statement
11134	/// }
11135	/// }
11136	///
11137	/// The body of the loop is not available yet, since it cannot be analysed
11138	/// until we have determined the type of the for-range-declaration.
11139	StmtResult ActOnCXXForRangeStmt(
11140	Scope *S, SourceLocation ForLoc, SourceLocation CoawaitLoc,
11141	Stmt InitStmt, Stmt LoopVar, SourceLocation ColonLoc, Expr *Collection,
11142	SourceLocation RParenLoc, BuildForRangeKind Kind,
11143	ArrayRef<MaterializeTemporaryExpr *> LifetimeExtendTemps = {});
11144
11145	/// BuildCXXForRangeStmt - Build or instantiate a C++11 for-range statement.
11146	StmtResult BuildCXXForRangeStmt(
11147	SourceLocation ForLoc, SourceLocation CoawaitLoc, Stmt *InitStmt,
11148	SourceLocation ColonLoc, Stmt RangeDecl, Stmt Begin, Stmt *End,
11149	Expr Cond, Expr Inc, Stmt *LoopVarDecl, SourceLocation RParenLoc,
11150	BuildForRangeKind Kind,
11151	ArrayRef<MaterializeTemporaryExpr *> LifetimeExtendTemps = {});
11152
11153	/// FinishCXXForRangeStmt - Attach the body to a C++0x for-range statement.
11154	/// This is a separate step from ActOnCXXForRangeStmt because analysis of the
11155	/// body cannot be performed until after the type of the range variable is
11156	/// determined.
11157	StmtResult FinishCXXForRangeStmt(Stmt ForRange, Stmt Body);
11158
11159	StmtResult ActOnGotoStmt(SourceLocation GotoLoc, SourceLocation LabelLoc,
11160	LabelDecl *TheDecl);
11161	StmtResult ActOnIndirectGotoStmt(SourceLocation GotoLoc,
11162	SourceLocation StarLoc, Expr *DestExp);
11163	StmtResult ActOnContinueStmt(SourceLocation ContinueLoc, Scope *CurScope,
11164	LabelDecl *Label, SourceLocation LabelLoc);
11165	StmtResult ActOnBreakStmt(SourceLocation BreakLoc, Scope *CurScope,
11166	LabelDecl *Label, SourceLocation LabelLoc);
11167
11168	void ActOnStartOfDeferStmt(SourceLocation DeferLoc, Scope *CurScope);
11169	void ActOnDeferStmtError(Scope *CurScope);
11170	StmtResult ActOnEndOfDeferStmt(Stmt Body, Scope CurScope);
11171
11172	struct NamedReturnInfo {
11173	const VarDecl *Candidate;
11174
11175	enum Status : uint8_t { None, MoveEligible, MoveEligibleAndCopyElidable };
11176	Status S;
11177
11178	bool isMoveEligible() const { return S != None; };
11179	bool isCopyElidable() const { return S == MoveEligibleAndCopyElidable; }
11180	};
11181	enum class SimplerImplicitMoveMode { ForceOff, Normal, ForceOn };
11182
11183	/// Determine whether the given expression might be move-eligible or
11184	/// copy-elidable in either a (co_)return statement or throw expression,
11185	/// without considering function return type, if applicable.
11186	///
11187	/// \param E The expression being returned from the function or block,
11188	/// being thrown, or being co_returned from a coroutine. This expression
11189	/// might be modified by the implementation.
11190	///
11191	/// \param Mode Overrides detection of current language mode
11192	/// and uses the rules for C++23.
11193	///
11194	/// \returns An aggregate which contains the Candidate and isMoveEligible
11195	/// and isCopyElidable methods. If Candidate is non-null, it means
11196	/// isMoveEligible() would be true under the most permissive language
11197	/// standard.
11198	NamedReturnInfo getNamedReturnInfo(
11199	Expr *&E, SimplerImplicitMoveMode Mode = SimplerImplicitMoveMode::Normal);
11200
11201	/// Determine whether the given NRVO candidate variable is move-eligible or
11202	/// copy-elidable, without considering function return type.
11203	///
11204	/// \param VD The NRVO candidate variable.
11205	///
11206	/// \returns An aggregate which contains the Candidate and isMoveEligible
11207	/// and isCopyElidable methods. If Candidate is non-null, it means
11208	/// isMoveEligible() would be true under the most permissive language
11209	/// standard.
11210	NamedReturnInfo getNamedReturnInfo(const VarDecl *VD);
11211
11212	/// Updates given NamedReturnInfo's move-eligible and
11213	/// copy-elidable statuses, considering the function
11214	/// return type criteria as applicable to return statements.
11215	///
11216	/// \param Info The NamedReturnInfo object to update.
11217	///
11218	/// \param ReturnType This is the return type of the function.
11219	/// \returns The copy elision candidate, in case the initial return expression
11220	/// was copy elidable, or nullptr otherwise.
11221	const VarDecl *getCopyElisionCandidate(NamedReturnInfo &Info,
11222	QualType ReturnType);
11223
11224	/// Perform the initialization of a potentially-movable value, which
11225	/// is the result of return value.
11226	///
11227	/// This routine implements C++20 [class.copy.elision]p3, which attempts to
11228	/// treat returned lvalues as rvalues in certain cases (to prefer move
11229	/// construction), then falls back to treating them as lvalues if that failed.
11230	ExprResult
11231	PerformMoveOrCopyInitialization(const InitializedEntity &Entity,
11232	const NamedReturnInfo &NRInfo, Expr *Value,
11233	bool SupressSimplerImplicitMoves = false);
11234
11235	TypeLoc getReturnTypeLoc(FunctionDecl FD) const*;
11236
11237	/// Deduce the return type for a function from a returned expression, per
11238	/// C++1y [dcl.spec.auto]p6.
11239	bool DeduceFunctionTypeFromReturnExpr(FunctionDecl *FD,
11240	SourceLocation ReturnLoc, Expr *RetExpr,
11241	const AutoType *AT);
11242
11243	StmtResult ActOnReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp,
11244	Scope *CurScope);
11245	StmtResult BuildReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp,
11246	bool AllowRecovery = false);
11247
11248	/// ActOnCapScopeReturnStmt - Utility routine to type-check return statements
11249	/// for capturing scopes.
11250	StmtResult ActOnCapScopeReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp,
11251	NamedReturnInfo &NRInfo,
11252	bool SupressSimplerImplicitMoves);
11253
11254	/// ActOnCXXCatchBlock - Takes an exception declaration and a handler block
11255	/// and creates a proper catch handler from them.
11256	StmtResult ActOnCXXCatchBlock(SourceLocation CatchLoc, Decl *ExDecl,
11257	Stmt *HandlerBlock);
11258
11259	/// ActOnCXXTryBlock - Takes a try compound-statement and a number of
11260	/// handlers and creates a try statement from them.
11261	StmtResult ActOnCXXTryBlock(SourceLocation TryLoc, Stmt *TryBlock,
11262	ArrayRef<Stmt *> Handlers);
11263
11264	void DiagnoseExceptionUse(SourceLocation Loc, bool IsTry);
11265
11266	StmtResult ActOnSEHTryBlock(bool IsCXXTry, // try (true) or __try (false) ?
11267	SourceLocation TryLoc, Stmt *TryBlock,
11268	Stmt *Handler);
11269	StmtResult ActOnSEHExceptBlock(SourceLocation Loc, Expr *FilterExpr,
11270	Stmt *Block);
11271	void ActOnStartSEHFinallyBlock();
11272	void ActOnAbortSEHFinallyBlock();
11273	StmtResult ActOnFinishSEHFinallyBlock(SourceLocation Loc, Stmt *Block);
11274	StmtResult ActOnSEHLeaveStmt(SourceLocation Loc, Scope *CurScope);
11275
11276	StmtResult BuildMSDependentExistsStmt(SourceLocation KeywordLoc,
11277	bool IsIfExists,
11278	NestedNameSpecifierLoc QualifierLoc,
11279	DeclarationNameInfo NameInfo,
11280	Stmt *Nested);
11281	StmtResult ActOnMSDependentExistsStmt(SourceLocation KeywordLoc,
11282	bool IsIfExists, CXXScopeSpec &SS,
11283	UnqualifiedId &Name, Stmt *Nested);
11284
11285	void ActOnCapturedRegionStart(SourceLocation Loc, Scope *CurScope,
11286	CapturedRegionKind Kind, unsigned NumParams);
11287	typedef std::pair<StringRef, QualType> CapturedParamNameType;
11288	void ActOnCapturedRegionStart(SourceLocation Loc, Scope *CurScope,
11289	CapturedRegionKind Kind,
11290	ArrayRef<CapturedParamNameType> Params,
11291	unsigned OpenMPCaptureLevel = `0`);
11292	StmtResult ActOnCapturedRegionEnd(Stmt *S);
11293	void ActOnCapturedRegionError();
11294	RecordDecl CreateCapturedStmtRecordDecl(CapturedDecl &CD,
11295	SourceLocation Loc,
11296	unsigned NumParams);
11297
11298	private:
11299	/// Check whether the given statement can have musttail applied to it,
11300	/// issuing a diagnostic and returning false if not.
11301	bool checkMustTailAttr(const Stmt St, const* Attr &MTA);
11302
11303	/// Check if the given expression contains 'break' or 'continue'
11304	/// statement that produces control flow different from GCC.
11305	void CheckBreakContinueBinding(Expr *E);
11306
11307	///@}
11308
11309	//
11310	//
11311	// -------------------------------------------------------------------------
11312	//
11313	//
11314
11315	/// \name `inline asm` Statement
11316	/// Implementations are in SemaStmtAsm.cpp
11317	///@{
11318
11319	public:
11320	ExprResult ActOnGCCAsmStmtString(Expr Stm, bool* ForAsmLabel);
11321	StmtResult ActOnGCCAsmStmt(SourceLocation AsmLoc, bool IsSimple,
11322	bool IsVolatile, unsigned NumOutputs,
11323	unsigned NumInputs, IdentifierInfo **Names,
11324	MultiExprArg Constraints, MultiExprArg Exprs,
11325	Expr *AsmString, MultiExprArg Clobbers,
11326	unsigned NumLabels, SourceLocation RParenLoc);
11327
11328	void FillInlineAsmIdentifierInfo(Expr *Res,
11329	llvm::InlineAsmIdentifierInfo &Info);
11330	ExprResult LookupInlineAsmIdentifier(CXXScopeSpec &SS,
11331	SourceLocation TemplateKWLoc,
11332	UnqualifiedId &Id,
11333	bool IsUnevaluatedContext);
11334	bool LookupInlineAsmField(StringRef Base, StringRef Member, unsigned &Offset,
11335	SourceLocation AsmLoc);
11336	ExprResult LookupInlineAsmVarDeclField(Expr *RefExpr, StringRef Member,
11337	SourceLocation AsmLoc);
11338	StmtResult ActOnMSAsmStmt(SourceLocation AsmLoc, SourceLocation LBraceLoc,
11339	ArrayRef<Token> AsmToks, StringRef AsmString,
11340	unsigned NumOutputs, unsigned NumInputs,
11341	ArrayRef<StringRef> Constraints,
11342	ArrayRef<StringRef> Clobbers,
11343	ArrayRef<Expr *> Exprs, SourceLocation EndLoc);
11344	LabelDecl *GetOrCreateMSAsmLabel(StringRef ExternalLabelName,
11345	SourceLocation Location, bool AlwaysCreate);
11346
11347	///@}
11348
11349	//
11350	//
11351	// -------------------------------------------------------------------------
11352	//
11353	//
11354
11355	/// \name Statement Attribute Handling
11356	/// Implementations are in SemaStmtAttr.cpp
11357	///@{
11358
11359	public:
11360	bool CheckNoInlineAttr(const Stmt OrigSt, const* Stmt *CurSt,
11361	const AttributeCommonInfo &A);
11362	bool CheckAlwaysInlineAttr(const Stmt OrigSt, const* Stmt *CurSt,
11363	const AttributeCommonInfo &A);
11364
11365	CodeAlignAttr BuildCodeAlignAttr(const* AttributeCommonInfo &CI, Expr *E);
11366	bool CheckRebuiltStmtAttributes(ArrayRef<const Attr *> Attrs);
11367
11368	/// Process the attributes before creating an attributed statement. Returns
11369	/// the semantic attributes that have been processed.
11370	void ProcessStmtAttributes(Stmt Stmt, const* ParsedAttributes &InAttrs,
11371	SmallVectorImpl<const Attr *> &OutAttrs);
11372
11373	ExprResult ActOnCXXAssumeAttr(Stmt St, const* ParsedAttr &A,
11374	SourceRange Range);
11375	ExprResult BuildCXXAssumeExpr(Expr *Assumption,
11376	const IdentifierInfo *AttrName,
11377	SourceRange Range);
11378
11379	///@}
11380
11381	//
11382	//
11383	// -------------------------------------------------------------------------
11384	//
11385	//
11386
11387	/// \name C++ Templates
11388	/// Implementations are in SemaTemplate.cpp
11389	///@{
11390
11391	public:
11392	// Saves the current floating-point pragma stack and clear it in this Sema.
11393	class FpPragmaStackSaveRAII {
11394	public:
11395	FpPragmaStackSaveRAII(Sema &S)
11396	: S(S), SavedStack (std::move(S.FpPragmaStack)) {
11397	S.FpPragmaStack.Stack.clear();
11398	}
11399	~FpPragmaStackSaveRAII() { S.FpPragmaStack = std::move(SavedStack); }
11400	FpPragmaStackSaveRAII(const FpPragmaStackSaveRAII &) = delete;
11401	FpPragmaStackSaveRAII &operator=(const FpPragmaStackSaveRAII &) = delete;
11402
11403	private:
11404	Sema &S;
11405	PragmaStack<FPOptionsOverride> SavedStack;
11406	};
11407
11408	void resetFPOptions(FPOptions FPO) {
11409	CurFPFeatures = FPO;
11410	FpPragmaStack.CurrentValue = FPO.getChangesFrom(Base: FPOptions (LangOpts));
11411	}
11412
11413	ArrayRef<InventedTemplateParameterInfo> getInventedParameterInfos() const {
11414	return llvm::ArrayRef(InventedParameterInfos.begin() +
11415	InventedParameterInfosStart,
11416	InventedParameterInfos.end());
11417	}
11418
11419	ArrayRef<sema::FunctionScopeInfo > getFunctionScopes() const* {
11420	return llvm::ArrayRef(FunctionScopes.begin() + FunctionScopesStart,
11421	FunctionScopes.end());
11422	}
11423
11424	typedef llvm::MapVector<const FunctionDecl *,
11425	std::unique_ptr<LateParsedTemplate>>
11426	LateParsedTemplateMapT;
11427	LateParsedTemplateMapT LateParsedTemplateMap;
11428
11429	/// Determine the number of levels of enclosing template parameters. This is
11430	/// only usable while parsing. Note that this does not include dependent
11431	/// contexts in which no template parameters have yet been declared, such as
11432	/// in a terse function template or generic lambda before the first 'auto' is
11433	/// encountered.
11434	unsigned getTemplateDepth(Scope S) const*;
11435
11436	void FilterAcceptableTemplateNames(LookupResult &R,
11437	bool AllowFunctionTemplates = true,
11438	bool AllowDependent = true);
11439	bool hasAnyAcceptableTemplateNames(LookupResult &R,
11440	bool AllowFunctionTemplates = true,
11441	bool AllowDependent = true,
11442	bool AllowNonTemplateFunctions = false);
11443	/// Try to interpret the lookup result D as a template-name.
11444	///
11445	/// \param D A declaration found by name lookup.
11446	/// \param AllowFunctionTemplates Whether function templates should be
11447	/// considered valid results.
11448	/// \param AllowDependent Whether unresolved using declarations (that might
11449	/// name templates) should be considered valid results.
11450	static NamedDecl getAsTemplateNameDecl(NamedDecl D,
11451	bool AllowFunctionTemplates = true,
11452	bool AllowDependent = true);
11453
11454	enum TemplateNameIsRequiredTag { TemplateNameIsRequired };
11455	/// Whether and why a template name is required in this lookup.
11456	class RequiredTemplateKind {
11457	public:
11458	/// Template name is required if TemplateKWLoc is valid.
11459	RequiredTemplateKind(SourceLocation TemplateKWLoc = SourceLocation ())
11460	: TemplateKW (TemplateKWLoc) {}
11461	/// Template name is unconditionally required.
11462	RequiredTemplateKind(TemplateNameIsRequiredTag) {}
11463
11464	SourceLocation getTemplateKeywordLoc() const {
11465	return TemplateKW.value_or(u: SourceLocation ());
11466	}
11467	bool hasTemplateKeyword() const {
11468	return getTemplateKeywordLoc().isValid();
11469	}
11470	bool isRequired() const { return TemplateKW != SourceLocation (); }
11471	explicit operator bool() const { return isRequired(); }
11472
11473	private:
11474	std::optional<SourceLocation> TemplateKW;
11475	};
11476
11477	enum class AssumedTemplateKind {
11478	/// This is not assumed to be a template name.
11479	None,
11480	/// This is assumed to be a template name because lookup found nothing.
11481	FoundNothing,
11482	/// This is assumed to be a template name because lookup found one or more
11483	/// functions (but no function templates).
11484	FoundFunctions,
11485	};
11486
11487	bool
11488	LookupTemplateName(LookupResult &R, Scope *S, CXXScopeSpec &SS,
11489	QualType ObjectType, bool EnteringContext,
11490	RequiredTemplateKind RequiredTemplate = SourceLocation (),
11491	AssumedTemplateKind ATK = nullptr*,
11492	bool AllowTypoCorrection = true);
11493
11494	TemplateNameKind isTemplateName(Scope *S, CXXScopeSpec &SS,
11495	bool hasTemplateKeyword,
11496	const UnqualifiedId &Name,
11497	ParsedType ObjectType, bool EnteringContext,
11498	TemplateTy &Template,
11499	bool &MemberOfUnknownSpecialization,
11500	bool Disambiguation = false);
11501
11502	/// Try to resolve an undeclared template name as a type template.
11503	///
11504	/// Sets II to the identifier corresponding to the template name, and updates
11505	/// Name to a corresponding (typo-corrected) type template name and TNK to
11506	/// the corresponding kind, if possible.
11507	void ActOnUndeclaredTypeTemplateName(Scope *S, TemplateTy &Name,
11508	TemplateNameKind &TNK,
11509	SourceLocation NameLoc,
11510	IdentifierInfo *&II);
11511
11512	/// Determine whether a particular identifier might be the name in a C++1z
11513	/// deduction-guide declaration.
11514	bool isDeductionGuideName(Scope S, const* IdentifierInfo &Name,
11515	SourceLocation NameLoc, CXXScopeSpec &SS,
11516	ParsedTemplateTy Template = nullptr*);
11517
11518	bool DiagnoseUnknownTemplateName(const IdentifierInfo &II,
11519	SourceLocation IILoc, Scope *S,
11520	const CXXScopeSpec *SS,
11521	TemplateTy &SuggestedTemplate,
11522	TemplateNameKind &SuggestedKind);
11523
11524	/// Determine whether we would be unable to instantiate this template (because
11525	/// it either has no definition, or is in the process of being instantiated).
11526	bool DiagnoseUninstantiableTemplate(
11527	SourceLocation PointOfInstantiation, NamedDecl *Instantiation,
11528	bool InstantiatedFromMember, const NamedDecl *Pattern,
11529	const NamedDecl *PatternDef, TemplateSpecializationKind TSK,
11530	bool Complain = true, bool Unreachable = nullptr*);
11531
11532	/// DiagnoseTemplateParameterShadow - Produce a diagnostic complaining
11533	/// that the template parameter 'PrevDecl' is being shadowed by a new
11534	/// declaration at location Loc. Returns true to indicate that this is
11535	/// an error, and false otherwise.
11536	///
11537	/// \param Loc The location of the declaration that shadows a template
11538	/// parameter.
11539	///
11540	/// \param PrevDecl The template parameter that the declaration shadows.
11541	///
11542	/// \param SupportedForCompatibility Whether to issue the diagnostic as
11543	/// a warning for compatibility with older versions of clang.
11544	/// Ignored when MSVC compatibility is enabled.
11545	void DiagnoseTemplateParameterShadow(SourceLocation Loc, Decl *PrevDecl,
11546	bool SupportedForCompatibility = false);
11547
11548	/// AdjustDeclIfTemplate - If the given decl happens to be a template, reset
11549	/// the parameter D to reference the templated declaration and return a
11550	/// pointer to the template declaration. Otherwise, do nothing to D and return
11551	/// null.
11552	TemplateDecl AdjustDeclIfTemplate(Decl &Decl);
11553
11554	/// ActOnTypeParameter - Called when a C++ template type parameter
11555	/// (e.g., "typename T") has been parsed. Typename specifies whether
11556	/// the keyword "typename" was used to declare the type parameter
11557	/// (otherwise, "class" was used), and KeyLoc is the location of the
11558	/// "class" or "typename" keyword. ParamName is the name of the
11559	/// parameter (NULL indicates an unnamed template parameter) and
11560	/// ParamNameLoc is the location of the parameter name (if any).
11561	/// If the type parameter has a default argument, it will be added
11562	/// later via ActOnTypeParameterDefault.
11563	NamedDecl ActOnTypeParameter(Scope S, bool Typename,
11564	SourceLocation EllipsisLoc,
11565	SourceLocation KeyLoc,
11566	IdentifierInfo *ParamName,
11567	SourceLocation ParamNameLoc, unsigned Depth,
11568	unsigned Position, SourceLocation EqualLoc,
11569	ParsedType DefaultArg, bool HasTypeConstraint);
11570
11571	bool CheckTypeConstraint(TemplateIdAnnotation *TypeConstraint);
11572
11573	bool ActOnTypeConstraint(const CXXScopeSpec &SS,
11574	TemplateIdAnnotation *TypeConstraint,
11575	TemplateTypeParmDecl *ConstrainedParameter,
11576	SourceLocation EllipsisLoc);
11577	bool BuildTypeConstraint(const CXXScopeSpec &SS,
11578	TemplateIdAnnotation *TypeConstraint,
11579	TemplateTypeParmDecl *ConstrainedParameter,
11580	SourceLocation EllipsisLoc,
11581	bool AllowUnexpandedPack);
11582
11583	/// Attach a type-constraint to a template parameter.
11584	/// \returns true if an error occurred. This can happen if the
11585	/// immediately-declared constraint could not be formed (e.g. incorrect number
11586	/// of arguments for the named concept).
11587	bool AttachTypeConstraint(NestedNameSpecifierLoc NS,
11588	DeclarationNameInfo NameInfo,
11589	TemplateDecl NamedConcept, NamedDecl FoundDecl,
11590	const TemplateArgumentListInfo *TemplateArgs,
11591	TemplateTypeParmDecl *ConstrainedParameter,
11592	SourceLocation EllipsisLoc);
11593
11594	bool AttachTypeConstraint(AutoTypeLoc TL,
11595	NonTypeTemplateParmDecl *NewConstrainedParm,
11596	NonTypeTemplateParmDecl *OrigConstrainedParm,
11597	SourceLocation EllipsisLoc);
11598
11599	/// Require the given type to be a structural type, and diagnose if it is not.
11600	///
11601	/// \return \c true if an error was produced.
11602	bool RequireStructuralType(QualType T, SourceLocation Loc);
11603
11604	/// Check that the type of a non-type template parameter is
11605	/// well-formed.
11606	///
11607	/// \returns the (possibly-promoted) parameter type if valid;
11608	/// otherwise, produces a diagnostic and returns a NULL type.
11609	QualType CheckNonTypeTemplateParameterType(TypeSourceInfo *&TSI,
11610	SourceLocation Loc);
11611	QualType CheckNonTypeTemplateParameterType(QualType T, SourceLocation Loc);
11612
11613	NamedDecl ActOnNonTypeTemplateParameter(Scope S, Declarator &D,
11614	unsigned Depth, unsigned Position,
11615	SourceLocation EqualLoc,
11616	Expr *DefaultArg);
11617
11618	/// ActOnTemplateTemplateParameter - Called when a C++ template template
11619	/// parameter (e.g. T in template <template \<typename> class T> class array)
11620	/// has been parsed. S is the current scope.
11621	NamedDecl *ActOnTemplateTemplateParameter(
11622	Scope *S, SourceLocation TmpLoc, TemplateNameKind Kind,
11623	bool TypenameKeyword, TemplateParameterList *Params,
11624	SourceLocation EllipsisLoc, IdentifierInfo *ParamName,
11625	SourceLocation ParamNameLoc, unsigned Depth, unsigned Position,
11626	SourceLocation EqualLoc, ParsedTemplateArgument DefaultArg);
11627
11628	/// ActOnTemplateParameterList - Builds a TemplateParameterList, optionally
11629	/// constrained by RequiresClause, that contains the template parameters in
11630	/// Params.
11631	TemplateParameterList *ActOnTemplateParameterList(
11632	unsigned Depth, SourceLocation ExportLoc, SourceLocation TemplateLoc,
11633	SourceLocation LAngleLoc, ArrayRef<NamedDecl *> Params,
11634	SourceLocation RAngleLoc, Expr *RequiresClause);
11635
11636	/// The context in which we are checking a template parameter list.
11637	enum TemplateParamListContext {
11638	// For this context, Class, Variable, TypeAlias, and non-pack Template
11639	// Template Parameters are treated uniformly.
11640	TPC_Other,
11641
11642	TPC_FunctionTemplate,
11643	TPC_ClassTemplateMember,
11644	TPC_FriendClassTemplate,
11645	TPC_FriendFunctionTemplate,
11646	TPC_FriendFunctionTemplateDefinition,
11647	TPC_TemplateTemplateParameterPack,
11648	};
11649
11650	/// Checks the validity of a template parameter list, possibly
11651	/// considering the template parameter list from a previous
11652	/// declaration.
11653	///
11654	/// If an "old" template parameter list is provided, it must be
11655	/// equivalent (per TemplateParameterListsAreEqual) to the "new"
11656	/// template parameter list.
11657	///
11658	/// \param NewParams Template parameter list for a new template
11659	/// declaration. This template parameter list will be updated with any
11660	/// default arguments that are carried through from the previous
11661	/// template parameter list.
11662	///
11663	/// \param OldParams If provided, template parameter list from a
11664	/// previous declaration of the same template. Default template
11665	/// arguments will be merged from the old template parameter list to
11666	/// the new template parameter list.
11667	///
11668	/// \param TPC Describes the context in which we are checking the given
11669	/// template parameter list.
11670	///
11671	/// \param SkipBody If we might have already made a prior merged definition
11672	/// of this template visible, the corresponding body-skipping information.
11673	/// Default argument redefinition is not an error when skipping such a body,
11674	/// because (under the ODR) we can assume the default arguments are the same
11675	/// as the prior merged definition.
11676	///
11677	/// \returns true if an error occurred, false otherwise.
11678	bool CheckTemplateParameterList(TemplateParameterList *NewParams,
11679	TemplateParameterList *OldParams,
11680	TemplateParamListContext TPC,
11681	SkipBodyInfo SkipBody = nullptr*);
11682
11683	/// Match the given template parameter lists to the given scope
11684	/// specifier, returning the template parameter list that applies to the
11685	/// name.
11686	///
11687	/// \param DeclStartLoc the start of the declaration that has a scope
11688	/// specifier or a template parameter list.
11689	///
11690	/// \param DeclLoc The location of the declaration itself.
11691	///
11692	/// \param SS the scope specifier that will be matched to the given template
11693	/// parameter lists. This scope specifier precedes a qualified name that is
11694	/// being declared.
11695	///
11696	/// \param TemplateId The template-id following the scope specifier, if there
11697	/// is one. Used to check for a missing 'template<>'.
11698	///
11699	/// \param ParamLists the template parameter lists, from the outermost to the
11700	/// innermost template parameter lists.
11701	///
11702	/// \param IsFriend Whether to apply the slightly different rules for
11703	/// matching template parameters to scope specifiers in friend
11704	/// declarations.
11705	///
11706	/// \param IsMemberSpecialization will be set true if the scope specifier
11707	/// denotes a fully-specialized type, and therefore this is a declaration of
11708	/// a member specialization.
11709	///
11710	/// \returns the template parameter list, if any, that corresponds to the
11711	/// name that is preceded by the scope specifier @p SS. This template
11712	/// parameter list may have template parameters (if we're declaring a
11713	/// template) or may have no template parameters (if we're declaring a
11714	/// template specialization), or may be NULL (if what we're declaring isn't
11715	/// itself a template).
11716	TemplateParameterList *MatchTemplateParametersToScopeSpecifier(
11717	SourceLocation DeclStartLoc, SourceLocation DeclLoc,
11718	const CXXScopeSpec &SS, TemplateIdAnnotation *TemplateId,
11719	ArrayRef<TemplateParameterList > ParamLists, bool* IsFriend,
11720	bool &IsMemberSpecialization, bool &Invalid,
11721	bool SuppressDiagnostic = false);
11722
11723	/// Returns the template parameter list with all default template argument
11724	/// information.
11725	TemplateParameterList GetTemplateParameterList(TemplateDecl TD);
11726
11727	DeclResult CheckClassTemplate(
11728	Scope S, unsigned* TagSpec, TagUseKind TUK, SourceLocation KWLoc,
11729	CXXScopeSpec &SS, IdentifierInfo *Name, SourceLocation NameLoc,
11730	const ParsedAttributesView &Attr, TemplateParameterList *TemplateParams,
11731	AccessSpecifier AS, SourceLocation ModulePrivateLoc,
11732	SourceLocation FriendLoc, unsigned NumOuterTemplateParamLists,
11733	TemplateParameterList **OuterTemplateParamLists,
11734	SkipBodyInfo SkipBody = nullptr*);
11735
11736	/// Translates template arguments as provided by the parser
11737	/// into template arguments used by semantic analysis.
11738	void translateTemplateArguments(const ASTTemplateArgsPtr &In,
11739	TemplateArgumentListInfo &Out);
11740
11741	/// Convert a parsed type into a parsed template argument. This is mostly
11742	/// trivial, except that we may have parsed a C++17 deduced class template
11743	/// specialization type, in which case we should form a template template
11744	/// argument instead of a type template argument.
11745	ParsedTemplateArgument ActOnTemplateTypeArgument(TypeResult ParsedType);
11746
11747	void NoteAllFoundTemplates(TemplateName Name);
11748
11749	QualType CheckTemplateIdType(ElaboratedTypeKeyword Keyword,
11750	TemplateName Template,
11751	SourceLocation TemplateLoc,
11752	TemplateArgumentListInfo &TemplateArgs,
11753	Scope Scope, bool* ForNestedNameSpecifier);
11754
11755	TypeResult
11756	ActOnTemplateIdType(Scope *S, ElaboratedTypeKeyword ElaboratedKeyword,
11757	SourceLocation ElaboratedKeywordLoc, CXXScopeSpec &SS,
11758	SourceLocation TemplateKWLoc, TemplateTy Template,
11759	const IdentifierInfo *TemplateII,
11760	SourceLocation TemplateIILoc, SourceLocation LAngleLoc,
11761	ASTTemplateArgsPtr TemplateArgs, SourceLocation RAngleLoc,
11762	bool IsCtorOrDtorName = false, bool IsClassName = false,
11763	ImplicitTypenameContext AllowImplicitTypename =
11764	ImplicitTypenameContext::No);
11765
11766	/// Parsed an elaborated-type-specifier that refers to a template-id,
11767	/// such as \c class T::template apply<U>.
11768	TypeResult ActOnTagTemplateIdType(
11769	TagUseKind TUK, TypeSpecifierType TagSpec, SourceLocation TagLoc,
11770	CXXScopeSpec &SS, SourceLocation TemplateKWLoc, TemplateTy TemplateD,
11771	SourceLocation TemplateLoc, SourceLocation LAngleLoc,
11772	ASTTemplateArgsPtr TemplateArgsIn, SourceLocation RAngleLoc);
11773
11774	DeclResult ActOnVarTemplateSpecialization(
11775	Scope S, Declarator &D, TypeSourceInfo TSI, LookupResult &Previous,
11776	SourceLocation TemplateKWLoc, TemplateParameterList *TemplateParams,
11777	StorageClass SC, bool IsPartialSpecialization);
11778
11779	/// Get the specialization of the given variable template corresponding to
11780	/// the specified argument list, or a null-but-valid result if the arguments
11781	/// are dependent.
11782	DeclResult CheckVarTemplateId(VarTemplateDecl *Template,
11783	SourceLocation TemplateLoc,
11784	SourceLocation TemplateNameLoc,
11785	const TemplateArgumentListInfo &TemplateArgs,
11786	bool SetWrittenArgs);
11787
11788	/// Form a reference to the specialization of the given variable template
11789	/// corresponding to the specified argument list, or a null-but-valid result
11790	/// if the arguments are dependent.
11791	ExprResult CheckVarTemplateId(const CXXScopeSpec &SS,
11792	const DeclarationNameInfo &NameInfo,
11793	VarTemplateDecl Template, NamedDecl FoundD,
11794	SourceLocation TemplateLoc,
11795	const TemplateArgumentListInfo *TemplateArgs);
11796
11797	ExprResult CheckVarOrConceptTemplateTemplateId(
11798	const CXXScopeSpec &SS, const DeclarationNameInfo &NameInfo,
11799	TemplateTemplateParmDecl *Template, SourceLocation TemplateLoc,
11800	const TemplateArgumentListInfo *TemplateArgs);
11801
11802	ExprResult
11803	CheckConceptTemplateId(const CXXScopeSpec &SS, SourceLocation TemplateKWLoc,
11804	const DeclarationNameInfo &ConceptNameInfo,
11805	NamedDecl FoundDecl, TemplateDecl NamedConcept,
11806	const TemplateArgumentListInfo *TemplateArgs,
11807	bool DoCheckConstraintSatisfaction = true);
11808
11809	void diagnoseMissingTemplateArguments(TemplateName Name, SourceLocation Loc);
11810	void diagnoseMissingTemplateArguments(const CXXScopeSpec &SS,
11811	bool TemplateKeyword, TemplateDecl *TD,
11812	SourceLocation Loc);
11813
11814	ExprResult BuildTemplateIdExpr(const CXXScopeSpec &SS,
11815	SourceLocation TemplateKWLoc, LookupResult &R,
11816	bool RequiresADL,
11817	const TemplateArgumentListInfo *TemplateArgs);
11818
11819	// We actually only call this from template instantiation.
11820	ExprResult
11821	BuildQualifiedTemplateIdExpr(CXXScopeSpec &SS, SourceLocation TemplateKWLoc,
11822	const DeclarationNameInfo &NameInfo,
11823	const TemplateArgumentListInfo *TemplateArgs,
11824	bool IsAddressOfOperand);
11825
11826	UnsignedOrNone getPackIndex(TemplateArgument Pack) const {
11827	return Pack.pack_size() - `1` - *ArgPackSubstIndex;
11828	}
11829
11830	TemplateArgument
11831	getPackSubstitutedTemplateArgument(TemplateArgument Arg) const {
11832	Arg = Arg.pack_elements()[*ArgPackSubstIndex];
11833	if (Arg.isPackExpansion())
11834	Arg = Arg.getPackExpansionPattern();
11835	return Arg;
11836	}
11837
11838	ExprResult BuildSubstNonTypeTemplateParmExpr(
11839	Decl AssociatedDecl, const* NonTypeTemplateParmDecl *NTTP,
11840	SourceLocation loc, TemplateArgument Replacement,
11841	UnsignedOrNone PackIndex, bool Final);
11842
11843	/// Form a template name from a name that is syntactically required to name a
11844	/// template, either due to use of the 'template' keyword or because a name in
11845	/// this syntactic context is assumed to name a template (C++
11846	/// [temp.names]p2-4).
11847	///
11848	/// This action forms a template name given the name of the template and its
11849	/// optional scope specifier. This is used when the 'template' keyword is used
11850	/// or when the parsing context unambiguously treats a following '<' as
11851	/// introducing a template argument list. Note that this may produce a
11852	/// non-dependent template name if we can perform the lookup now and identify
11853	/// the named template.
11854	///
11855	/// For example, given "x.MetaFun::template apply", the scope specifier
11856	/// \p SS will be "MetaFun::", \p TemplateKWLoc contains the location
11857	/// of the "template" keyword, and "apply" is the \p Name.
11858	TemplateNameKind ActOnTemplateName(Scope *S, CXXScopeSpec &SS,
11859	SourceLocation TemplateKWLoc,
11860	const UnqualifiedId &Name,
11861	ParsedType ObjectType,
11862	bool EnteringContext, TemplateTy &Template,
11863	bool AllowInjectedClassName = false);
11864
11865	DeclResult ActOnClassTemplateSpecialization(
11866	Scope S, unsigned* TagSpec, TagUseKind TUK, SourceLocation KWLoc,
11867	SourceLocation ModulePrivateLoc, CXXScopeSpec &SS,
11868	TemplateIdAnnotation &TemplateId, const ParsedAttributesView &Attr,
11869	MultiTemplateParamsArg TemplateParameterLists,
11870	SkipBodyInfo SkipBody = nullptr*);
11871
11872	/// Check the non-type template arguments of a class template
11873	/// partial specialization according to C++ [temp.class.spec]p9.
11874	///
11875	/// \param TemplateNameLoc the location of the template name.
11876	/// \param PrimaryTemplate the template parameters of the primary class
11877	/// template.
11878	/// \param NumExplicit the number of explicitly-specified template arguments.
11879	/// \param TemplateArgs the template arguments of the class template
11880	/// partial specialization.
11881	///
11882	/// \returns \c true if there was an error, \c false otherwise.
11883	bool CheckTemplatePartialSpecializationArgs(SourceLocation Loc,
11884	TemplateDecl *PrimaryTemplate,
11885	unsigned NumExplicitArgs,
11886	ArrayRef<TemplateArgument> Args);
11887	void CheckTemplatePartialSpecialization(
11888	ClassTemplatePartialSpecializationDecl *Partial);
11889	void CheckTemplatePartialSpecialization(
11890	VarTemplatePartialSpecializationDecl *Partial);
11891
11892	Decl ActOnTemplateDeclarator(Scope S,
11893	MultiTemplateParamsArg TemplateParameterLists,
11894	Declarator &D);
11895
11896	/// Diagnose cases where we have an explicit template specialization
11897	/// before/after an explicit template instantiation, producing diagnostics
11898	/// for those cases where they are required and determining whether the
11899	/// new specialization/instantiation will have any effect.
11900	///
11901	/// \param NewLoc the location of the new explicit specialization or
11902	/// instantiation.
11903	///
11904	/// \param NewTSK the kind of the new explicit specialization or
11905	/// instantiation.
11906	///
11907	/// \param PrevDecl the previous declaration of the entity.
11908	///
11909	/// \param PrevTSK the kind of the old explicit specialization or
11910	/// instantiatin.
11911	///
11912	/// \param PrevPointOfInstantiation if valid, indicates where the previous
11913	/// declaration was instantiated (either implicitly or explicitly).
11914	///
11915	/// \param HasNoEffect will be set to true to indicate that the new
11916	/// specialization or instantiation has no effect and should be ignored.
11917	///
11918	/// \returns true if there was an error that should prevent the introduction
11919	/// of the new declaration into the AST, false otherwise.
11920	bool CheckSpecializationInstantiationRedecl(
11921	SourceLocation NewLoc,
11922	TemplateSpecializationKind ActOnExplicitInstantiationNewTSK,
11923	NamedDecl *PrevDecl, TemplateSpecializationKind PrevTSK,
11924	SourceLocation PrevPtOfInstantiation, bool &SuppressNew);
11925
11926	/// Perform semantic analysis for the given dependent function
11927	/// template specialization.
11928	///
11929	/// The only possible way to get a dependent function template specialization
11930	/// is with a friend declaration, like so:
11931	///
11932	/// \code
11933	/// template \<class T> void foo(T);
11934	/// template \<class T> class A {
11935	/// friend void foo<>(T);
11936	/// };
11937	/// \endcode
11938	///
11939	/// There really isn't any useful analysis we can do here, so we
11940	/// just store the information.
11941	bool CheckDependentFunctionTemplateSpecialization(
11942	FunctionDecl FD, const* TemplateArgumentListInfo *ExplicitTemplateArgs,
11943	LookupResult &Previous);
11944
11945	/// Perform semantic analysis for the given function template
11946	/// specialization.
11947	///
11948	/// This routine performs all of the semantic analysis required for an
11949	/// explicit function template specialization. On successful completion,
11950	/// the function declaration \p FD will become a function template
11951	/// specialization.
11952	///
11953	/// \param FD the function declaration, which will be updated to become a
11954	/// function template specialization.
11955	///
11956	/// \param ExplicitTemplateArgs the explicitly-provided template arguments,
11957	/// if any. Note that this may be valid info even when 0 arguments are
11958	/// explicitly provided as in, e.g., \c void sort<>(char, char);
11959	/// as it anyway contains info on the angle brackets locations.
11960	///
11961	/// \param Previous the set of declarations that may be specialized by
11962	/// this function specialization.
11963	///
11964	/// \param QualifiedFriend whether this is a lookup for a qualified friend
11965	/// declaration with no explicit template argument list that might be
11966	/// befriending a function template specialization.
11967	bool CheckFunctionTemplateSpecialization(
11968	FunctionDecl FD, TemplateArgumentListInfo ExplicitTemplateArgs,
11969	LookupResult &Previous, bool QualifiedFriend = false);
11970
11971	/// Perform semantic analysis for the given non-template member
11972	/// specialization.
11973	///
11974	/// This routine performs all of the semantic analysis required for an
11975	/// explicit member function specialization. On successful completion,
11976	/// the function declaration \p FD will become a member function
11977	/// specialization.
11978	///
11979	/// \param Member the member declaration, which will be updated to become a
11980	/// specialization.
11981	///
11982	/// \param Previous the set of declarations, one of which may be specialized
11983	/// by this function specialization; the set will be modified to contain the
11984	/// redeclared member.
11985	bool CheckMemberSpecialization(NamedDecl *Member, LookupResult &Previous);
11986	void CompleteMemberSpecialization(NamedDecl *Member, LookupResult &Previous);
11987
11988	// Explicit instantiation of a class template specialization
11989	DeclResult ActOnExplicitInstantiation(
11990	Scope *S, SourceLocation ExternLoc, SourceLocation TemplateLoc,
11991	unsigned TagSpec, SourceLocation KWLoc, const CXXScopeSpec &SS,
11992	TemplateTy Template, SourceLocation TemplateNameLoc,
11993	SourceLocation LAngleLoc, ASTTemplateArgsPtr TemplateArgs,
11994	SourceLocation RAngleLoc, const ParsedAttributesView &Attr);
11995
11996	// Explicit instantiation of a member class of a class template.
11997	DeclResult ActOnExplicitInstantiation(Scope *S, SourceLocation ExternLoc,
11998	SourceLocation TemplateLoc,
11999	unsigned TagSpec, SourceLocation KWLoc,
12000	CXXScopeSpec &SS, IdentifierInfo *Name,
12001	SourceLocation NameLoc,
12002	const ParsedAttributesView &Attr);
12003
12004	DeclResult ActOnExplicitInstantiation(Scope *S, SourceLocation ExternLoc,
12005	SourceLocation TemplateLoc,
12006	Declarator &D);
12007
12008	/// If the given template parameter has a default template
12009	/// argument, substitute into that default template argument and
12010	/// return the corresponding template argument.
12011	TemplateArgumentLoc SubstDefaultTemplateArgumentIfAvailable(
12012	TemplateDecl *Template, SourceLocation TemplateKWLoc,
12013	SourceLocation TemplateNameLoc, SourceLocation RAngleLoc, Decl *Param,
12014	ArrayRef<TemplateArgument> SugaredConverted,
12015	ArrayRef<TemplateArgument> CanonicalConverted, bool &HasDefaultArg);
12016
12017	/// Returns the top most location responsible for the definition of \p N.
12018	/// If \p N is a a template specialization, this is the location
12019	/// of the top of the instantiation stack.
12020	/// Otherwise, the location of \p N is returned.
12021	SourceLocation getTopMostPointOfInstantiation(const NamedDecl ) const*;
12022
12023	/// Specifies the context in which a particular template
12024	/// argument is being checked.
12025	enum CheckTemplateArgumentKind {
12026	/// The template argument was specified in the code or was
12027	/// instantiated with some deduced template arguments.
12028	CTAK_Specified,
12029
12030	/// The template argument was deduced via template argument
12031	/// deduction.
12032	CTAK_Deduced,
12033
12034	/// The template argument was deduced from an array bound
12035	/// via template argument deduction.
12036	CTAK_DeducedFromArrayBound
12037	};
12038
12039	struct CheckTemplateArgumentInfo {
12040	explicit CheckTemplateArgumentInfo(bool PartialOrdering = false,
12041	bool MatchingTTP = false)
12042	: PartialOrdering(PartialOrdering), MatchingTTP(MatchingTTP) {}
12043	CheckTemplateArgumentInfo(const CheckTemplateArgumentInfo &) = delete;
12044	CheckTemplateArgumentInfo &
12045	operator=(const CheckTemplateArgumentInfo &) = delete;
12046
12047	/// The checked, converted argument will be added to the
12048	/// end of these vectors.
12049	SmallVector<TemplateArgument, `4`> SugaredConverted, CanonicalConverted;
12050
12051	/// The check is being performed in the context of partial ordering.
12052	bool PartialOrdering;
12053
12054	/// If true, assume these template arguments are
12055	/// the injected template arguments for a template template parameter.
12056	/// This will relax the requirement that all its possible uses are valid:
12057	/// TTP checking is loose, and assumes that invalid uses will be diagnosed
12058	/// during instantiation.
12059	bool MatchingTTP;
12060
12061	/// Is set to true when, in the context of TTP matching, a pack parameter
12062	/// matches non-pack arguments.
12063	bool StrictPackMatch = false;
12064	};
12065
12066	/// Check that the given template argument corresponds to the given
12067	/// template parameter.
12068	///
12069	/// \param Param The template parameter against which the argument will be
12070	/// checked.
12071	///
12072	/// \param Arg The template argument, which may be updated due to conversions.
12073	///
12074	/// \param Template The template in which the template argument resides.
12075	///
12076	/// \param TemplateLoc The location of the template name for the template
12077	/// whose argument list we're matching.
12078	///
12079	/// \param RAngleLoc The location of the right angle bracket ('>') that closes
12080	/// the template argument list.
12081	///
12082	/// \param ArgumentPackIndex The index into the argument pack where this
12083	/// argument will be placed. Only valid if the parameter is a parameter pack.
12084	///
12085	/// \param CTAK Describes how we arrived at this particular template argument:
12086	/// explicitly written, deduced, etc.
12087	///
12088	/// \returns true on error, false otherwise.
12089	bool CheckTemplateArgument(NamedDecl *Param, TemplateArgumentLoc &Arg,
12090	NamedDecl *Template, SourceLocation TemplateLoc,
12091	SourceLocation RAngleLoc,
12092	unsigned ArgumentPackIndex,
12093	CheckTemplateArgumentInfo &CTAI,
12094	CheckTemplateArgumentKind CTAK);
12095
12096	/// Check that the given template arguments can be provided to
12097	/// the given template, converting the arguments along the way.
12098	///
12099	/// \param Template The template to which the template arguments are being
12100	/// provided.
12101	///
12102	/// \param TemplateLoc The location of the template name in the source.
12103	///
12104	/// \param TemplateArgs The list of template arguments. If the template is
12105	/// a template template parameter, this function may extend the set of
12106	/// template arguments to also include substituted, defaulted template
12107	/// arguments.
12108	///
12109	/// \param PartialTemplateArgs True if the list of template arguments is
12110	/// intentionally partial, e.g., because we're checking just the initial
12111	/// set of template arguments.
12112	///
12113	/// \param Converted Will receive the converted, canonicalized template
12114	/// arguments.
12115	///
12116	/// \param UpdateArgsWithConversions If \c true, update \p TemplateArgs to
12117	/// contain the converted forms of the template arguments as written.
12118	/// Otherwise, \p TemplateArgs will not be modified.
12119	///
12120	/// \param ConstraintsNotSatisfied If provided, and an error occurred, will
12121	/// receive true if the cause for the error is the associated constraints of
12122	/// the template not being satisfied by the template arguments.
12123	///
12124	/// \param DefaultArgs any default arguments from template specialization
12125	/// deduction.
12126	///
12127	/// \returns true if an error occurred, false otherwise.
12128	bool CheckTemplateArgumentList(TemplateDecl *Template,
12129	SourceLocation TemplateLoc,
12130	TemplateArgumentListInfo &TemplateArgs,
12131	const DefaultArguments &DefaultArgs,
12132	bool PartialTemplateArgs,
12133	CheckTemplateArgumentInfo &CTAI,
12134	bool UpdateArgsWithConversions = true,
12135	bool ConstraintsNotSatisfied = nullptr*);
12136
12137	bool CheckTemplateArgumentList(
12138	TemplateDecl Template, TemplateParameterList Params,
12139	SourceLocation TemplateLoc, TemplateArgumentListInfo &TemplateArgs,
12140	const DefaultArguments &DefaultArgs, bool PartialTemplateArgs,
12141	CheckTemplateArgumentInfo &CTAI, bool UpdateArgsWithConversions = true,
12142	bool ConstraintsNotSatisfied = nullptr*);
12143
12144	bool CheckTemplateTypeArgument(
12145	TemplateTypeParmDecl *Param, TemplateArgumentLoc &Arg,
12146	SmallVectorImpl<TemplateArgument> &SugaredConverted,
12147	SmallVectorImpl<TemplateArgument> &CanonicalConverted);
12148
12149	/// Check a template argument against its corresponding
12150	/// template type parameter.
12151	///
12152	/// This routine implements the semantics of C++ [temp.arg.type]. It
12153	/// returns true if an error occurred, and false otherwise.
12154	bool CheckTemplateArgument(TypeSourceInfo *Arg);
12155
12156	/// Check a template argument against its corresponding
12157	/// non-type template parameter.
12158	///
12159	/// This routine implements the semantics of C++ [temp.arg.nontype].
12160	/// If an error occurred, it returns ExprError(); otherwise, it
12161	/// returns the converted template argument. \p ParamType is the
12162	/// type of the non-type template parameter after it has been instantiated.
12163	ExprResult CheckTemplateArgument(NamedDecl *Param,
12164	QualType InstantiatedParamType, Expr *Arg,
12165	TemplateArgument &SugaredConverted,
12166	TemplateArgument &CanonicalConverted,
12167	bool StrictCheck,
12168	CheckTemplateArgumentKind CTAK);
12169
12170	/// Check a template argument against its corresponding
12171	/// template template parameter.
12172	///
12173	/// This routine implements the semantics of C++ [temp.arg.template].
12174	/// It returns true if an error occurred, and false otherwise.
12175	bool CheckTemplateTemplateArgument(TemplateTemplateParmDecl *Param,
12176	TemplateParameterList *Params,
12177	TemplateArgumentLoc &Arg,
12178	bool PartialOrdering,
12179	bool *StrictPackMatch);
12180
12181	bool CheckDeclCompatibleWithTemplateTemplate(TemplateDecl *Template,
12182	TemplateTemplateParmDecl *Param,
12183	const TemplateArgumentLoc &Arg);
12184
12185	void NoteTemplateLocation(const NamedDecl &Decl,
12186	std::optional<SourceRange> ParamRange = {});
12187	void NoteTemplateParameterLocation(const NamedDecl &Decl);
12188
12189	/// Given a non-type template argument that refers to a
12190	/// declaration and the type of its corresponding non-type template
12191	/// parameter, produce an expression that properly refers to that
12192	/// declaration.
12193	/// FIXME: This is used in some contexts where the resulting expression
12194	/// doesn't need to live too long. It would be useful if this function
12195	/// could return a temporary expression.
12196	ExprResult BuildExpressionFromDeclTemplateArgument(
12197	const TemplateArgument &Arg, QualType ParamType, SourceLocation Loc,
12198	NamedDecl TemplateParam = nullptr*);
12199	ExprResult
12200	BuildExpressionFromNonTypeTemplateArgument(const TemplateArgument &Arg,
12201	SourceLocation Loc);
12202
12203	/// Enumeration describing how template parameter lists are compared
12204	/// for equality.
12205	enum TemplateParameterListEqualKind {
12206	/// We are matching the template parameter lists of two templates
12207	/// that might be redeclarations.
12208	///
12209	/// \code
12210	/// template<typename T> struct X;
12211	/// template<typename T> struct X;
12212	/// \endcode
12213	TPL_TemplateMatch,
12214
12215	/// We are matching the template parameter lists of two template
12216	/// template parameters as part of matching the template parameter lists
12217	/// of two templates that might be redeclarations.
12218	///
12219	/// \code
12220	/// template<template<int I> class TT> struct X;
12221	/// template<template<int Value> class Other> struct X;
12222	/// \endcode
12223	TPL_TemplateTemplateParmMatch,
12224
12225	/// We are determining whether the template-parameters are equivalent
12226	/// according to C++ [temp.over.link]/6. This comparison does not consider
12227	/// constraints.
12228	///
12229	/// \code
12230	/// template<C1 T> void f(T);
12231	/// template<C2 T> void f(T);
12232	/// \endcode
12233	TPL_TemplateParamsEquivalent,
12234	};
12235
12236	// A struct to represent the 'new' declaration, which is either itself just
12237	// the named decl, or the important information we need about it in order to
12238	// do constraint comparisons.
12239	class TemplateCompareNewDeclInfo {
12240	const NamedDecl ND = nullptr*;
12241	const DeclContext DC = nullptr*;
12242	const DeclContext LexicalDC = nullptr*;
12243	SourceLocation Loc;
12244
12245	public:
12246	TemplateCompareNewDeclInfo(const NamedDecl *ND) : ND(ND) {}
12247	TemplateCompareNewDeclInfo(const DeclContext *DeclCtx,
12248	const DeclContext *LexicalDeclCtx,
12249	SourceLocation Loc)
12250
12251	: DC(DeclCtx), LexicalDC(LexicalDeclCtx), Loc (Loc) {
12252	assert(DC && LexicalDC &&
12253	"Constructor only for cases where we have the information to put "
12254	"in here");
12255	}
12256
12257	// If this was constructed with no information, we cannot do substitution
12258	// for constraint comparison, so make sure we can check that.
12259	bool isInvalid() const { return !ND && !DC; }
12260
12261	const NamedDecl getDecl() const* { return ND; }
12262
12263	bool ContainsDecl(const NamedDecl ND) const* { return this->ND == ND; }
12264
12265	const DeclContext getLexicalDeclContext() const* {
12266	return ND ? ND->getLexicalDeclContext() : LexicalDC;
12267	}
12268
12269	const DeclContext getDeclContext() const* {
12270	return ND ? ND->getDeclContext() : DC;
12271	}
12272
12273	SourceLocation getLocation() const { return ND ? ND->getLocation() : Loc; }
12274	};
12275
12276	/// Determine whether the given template parameter lists are
12277	/// equivalent.
12278	///
12279	/// \param New The new template parameter list, typically written in the
12280	/// source code as part of a new template declaration.
12281	///
12282	/// \param Old The old template parameter list, typically found via
12283	/// name lookup of the template declared with this template parameter
12284	/// list.
12285	///
12286	/// \param Complain If true, this routine will produce a diagnostic if
12287	/// the template parameter lists are not equivalent.
12288	///
12289	/// \param Kind describes how we are to match the template parameter lists.
12290	///
12291	/// \param TemplateArgLoc If this source location is valid, then we
12292	/// are actually checking the template parameter list of a template
12293	/// argument (New) against the template parameter list of its
12294	/// corresponding template template parameter (Old). We produce
12295	/// slightly different diagnostics in this scenario.
12296	///
12297	/// \returns True if the template parameter lists are equal, false
12298	/// otherwise.
12299	bool TemplateParameterListsAreEqual(
12300	const TemplateCompareNewDeclInfo &NewInstFrom, TemplateParameterList *New,
12301	const NamedDecl OldInstFrom, TemplateParameterList Old, bool Complain,
12302	TemplateParameterListEqualKind Kind,
12303	SourceLocation TemplateArgLoc = SourceLocation ());
12304
12305	bool TemplateParameterListsAreEqual(
12306	TemplateParameterList New, TemplateParameterList Old, bool Complain,
12307	TemplateParameterListEqualKind Kind,
12308	SourceLocation TemplateArgLoc = SourceLocation ()) {
12309	return TemplateParameterListsAreEqual(NewInstFrom: nullptr, New, OldInstFrom: nullptr, Old, Complain,
12310	Kind, TemplateArgLoc);
12311	}
12312
12313	/// Check whether a template can be declared within this scope.
12314	///
12315	/// If the template declaration is valid in this scope, returns
12316	/// false. Otherwise, issues a diagnostic and returns true.
12317	bool CheckTemplateDeclScope(Scope S, TemplateParameterList TemplateParams);
12318
12319	/// Called when the parser has parsed a C++ typename
12320	/// specifier, e.g., "typename T::type".
12321	///
12322	/// \param S The scope in which this typename type occurs.
12323	/// \param TypenameLoc the location of the 'typename' keyword
12324	/// \param SS the nested-name-specifier following the typename (e.g., 'T::').
12325	/// \param II the identifier we're retrieving (e.g., 'type' in the example).
12326	/// \param IdLoc the location of the identifier.
12327	/// \param IsImplicitTypename context where T::type refers to a type.
12328	TypeResult ActOnTypenameType(
12329	Scope S, SourceLocation TypenameLoc, const* CXXScopeSpec &SS,
12330	const IdentifierInfo &II, SourceLocation IdLoc,
12331	ImplicitTypenameContext IsImplicitTypename = ImplicitTypenameContext::No);
12332
12333	/// Called when the parser has parsed a C++ typename
12334	/// specifier that ends in a template-id, e.g.,
12335	/// "typename MetaFun::template apply<T1, T2>".
12336	///
12337	/// \param S The scope in which this typename type occurs.
12338	/// \param TypenameLoc the location of the 'typename' keyword
12339	/// \param SS the nested-name-specifier following the typename (e.g., 'T::').
12340	/// \param TemplateLoc the location of the 'template' keyword, if any.
12341	/// \param TemplateName The template name.
12342	/// \param TemplateII The identifier used to name the template.
12343	/// \param TemplateIILoc The location of the template name.
12344	/// \param LAngleLoc The location of the opening angle bracket ('<').
12345	/// \param TemplateArgs The template arguments.
12346	/// \param RAngleLoc The location of the closing angle bracket ('>').
12347	TypeResult
12348	ActOnTypenameType(Scope *S, SourceLocation TypenameLoc,
12349	const CXXScopeSpec &SS, SourceLocation TemplateLoc,
12350	TemplateTy TemplateName, const IdentifierInfo *TemplateII,
12351	SourceLocation TemplateIILoc, SourceLocation LAngleLoc,
12352	ASTTemplateArgsPtr TemplateArgs, SourceLocation RAngleLoc);
12353
12354	QualType CheckTypenameType(ElaboratedTypeKeyword Keyword,
12355	SourceLocation KeywordLoc,
12356	NestedNameSpecifierLoc QualifierLoc,
12357	const IdentifierInfo &II, SourceLocation IILoc,
12358	TypeSourceInfo *TSI, bool* DeducedTSTContext);
12359
12360	QualType CheckTypenameType(ElaboratedTypeKeyword Keyword,
12361	SourceLocation KeywordLoc,
12362	NestedNameSpecifierLoc QualifierLoc,
12363	const IdentifierInfo &II, SourceLocation IILoc,
12364	bool DeducedTSTContext = true);
12365
12366	/// Rebuilds a type within the context of the current instantiation.
12367	///
12368	/// The type \p T is part of the type of an out-of-line member definition of
12369	/// a class template (or class template partial specialization) that was
12370	/// parsed and constructed before we entered the scope of the class template
12371	/// (or partial specialization thereof). This routine will rebuild that type
12372	/// now that we have entered the declarator's scope, which may produce
12373	/// different canonical types, e.g.,
12374	///
12375	/// \code
12376	/// template<typename T>
12377	/// struct X {
12378	/// typedef T pointer;*
12379	/// pointer data();
12380	/// };
12381	///
12382	/// template<typename T>
12383	/// typename X<T>::pointer X<T>::data() { ... }
12384	/// \endcode
12385	///
12386	/// Here, the type "typename X<T>::pointer" will be created as a
12387	/// DependentNameType, since we do not know that we can look into X<T> when we
12388	/// parsed the type. This function will rebuild the type, performing the
12389	/// lookup of "pointer" in X<T> and returning an ElaboratedType whose
12390	/// canonical type is the same as the canonical type of T, allowing the*
12391	/// return types of the out-of-line definition and the declaration to match.
12392	TypeSourceInfo RebuildTypeInCurrentInstantiation(TypeSourceInfo T,
12393	SourceLocation Loc,
12394	DeclarationName Name);
12395	bool RebuildNestedNameSpecifierInCurrentInstantiation(CXXScopeSpec &SS);
12396
12397	ExprResult RebuildExprInCurrentInstantiation(Expr *E);
12398
12399	/// Rebuild the template parameters now that we know we're in a current
12400	/// instantiation.
12401	bool
12402	RebuildTemplateParamsInCurrentInstantiation(TemplateParameterList *Params);
12403
12404	/// Produces a formatted string that describes the binding of
12405	/// template parameters to template arguments.
12406	std::string
12407	getTemplateArgumentBindingsText(const TemplateParameterList *Params,
12408	const TemplateArgumentList &Args);
12409
12410	std::string
12411	getTemplateArgumentBindingsText(const TemplateParameterList *Params,
12412	const TemplateArgument *Args,
12413	unsigned NumArgs);
12414
12415	void diagnoseExprIntendedAsTemplateName(Scope *S, ExprResult TemplateName,
12416	SourceLocation Less,
12417	SourceLocation Greater);
12418
12419	/// ActOnDependentIdExpression - Handle a dependent id-expression that
12420	/// was just parsed. This is only possible with an explicit scope
12421	/// specifier naming a dependent type.
12422	ExprResult ActOnDependentIdExpression(
12423	const CXXScopeSpec &SS, SourceLocation TemplateKWLoc,
12424	const DeclarationNameInfo &NameInfo, bool isAddressOfOperand,
12425	const TemplateArgumentListInfo *TemplateArgs);
12426
12427	ExprResult
12428	BuildDependentDeclRefExpr(const CXXScopeSpec &SS,
12429	SourceLocation TemplateKWLoc,
12430	const DeclarationNameInfo &NameInfo,
12431	const TemplateArgumentListInfo *TemplateArgs);
12432
12433	// Calculates whether the expression Constraint depends on an enclosing
12434	// template, for the purposes of [temp.friend] p9.
12435	// TemplateDepth is the 'depth' of the friend function, which is used to
12436	// compare whether a declaration reference is referring to a containing
12437	// template, or just the current friend function. A 'lower' TemplateDepth in
12438	// the AST refers to a 'containing' template. As the constraint is
12439	// uninstantiated, this is relative to the 'top' of the TU.
12440	bool
12441	ConstraintExpressionDependsOnEnclosingTemplate(const FunctionDecl *Friend,
12442	unsigned TemplateDepth,
12443	const Expr *Constraint);
12444
12445	/// Find the failed Boolean condition within a given Boolean
12446	/// constant expression, and describe it with a string.
12447	std::pair<Expr , std::string> findFailedBooleanCondition(Expr Cond);
12448
12449	void CheckDeductionGuideTemplate(FunctionTemplateDecl *TD);
12450
12451	ConceptDecl *ActOnStartConceptDefinition(
12452	Scope *S, MultiTemplateParamsArg TemplateParameterLists,
12453	const IdentifierInfo *Name, SourceLocation NameLoc);
12454
12455	ConceptDecl ActOnFinishConceptDefinition(Scope S, ConceptDecl *C,
12456	Expr *ConstraintExpr,
12457	const ParsedAttributesView &Attrs);
12458
12459	void CheckConceptRedefinition(ConceptDecl *NewDecl, LookupResult &Previous,
12460	bool &AddToScope);
12461	bool CheckConceptUseInDefinition(NamedDecl *Concept, SourceLocation Loc);
12462
12463	TypeResult ActOnDependentTag(Scope S, unsigned* TagSpec, TagUseKind TUK,
12464	const CXXScopeSpec &SS,
12465	const IdentifierInfo *Name,
12466	SourceLocation TagLoc, SourceLocation NameLoc);
12467
12468	void MarkAsLateParsedTemplate(FunctionDecl FD, Decl FnD,
12469	CachedTokens &Toks);
12470	void UnmarkAsLateParsedTemplate(FunctionDecl *FD);
12471	bool IsInsideALocalClassWithinATemplateFunction();
12472
12473	/// We've found a use of a templated declaration that would trigger an
12474	/// implicit instantiation. Check that any relevant explicit specializations
12475	/// and partial specializations are visible/reachable, and diagnose if not.
12476	void checkSpecializationVisibility(SourceLocation Loc, NamedDecl *Spec);
12477	void checkSpecializationReachability(SourceLocation Loc, NamedDecl *Spec);
12478
12479	///@}
12480
12481	//
12482	//
12483	// -------------------------------------------------------------------------
12484	//
12485	//
12486
12487	/// \name C++ Template Argument Deduction
12488	/// Implementations are in SemaTemplateDeduction.cpp
12489	///@{
12490
12491	public:
12492	class SFINAETrap;
12493
12494	struct SFINAEContextBase {
12495	SFINAEContextBase(Sema &S, SFINAETrap *Cur)
12496	: S(S), Prev(std::exchange(obj&: S.CurrentSFINAEContext, new_val&: Cur)) {}
12497
12498	protected:
12499	Sema &S;
12500	~SFINAEContextBase() { S.CurrentSFINAEContext = Prev; }
12501	SFINAEContextBase(const SFINAEContextBase &) = delete;
12502	SFINAEContextBase &operator=(const SFINAEContextBase &) = delete;
12503
12504	private:
12505	SFINAETrap *Prev;
12506	};
12507
12508	struct NonSFINAEContext : SFINAEContextBase {
12509	NonSFINAEContext(Sema &S) : SFINAEContextBase (S, nullptr) {}
12510	};
12511
12512	/// RAII class used to determine whether SFINAE has
12513	/// trapped any errors that occur during template argument
12514	/// deduction.
12515	class SFINAETrap : SFINAEContextBase {
12516	bool HasErrorOcurred = false;
12517	bool WithAccessChecking = false;
12518	bool PrevLastDiagnosticIgnored =
12519	S.getDiagnostics().isLastDiagnosticIgnored();
12520	sema::TemplateDeductionInfo DeductionInfo = nullptr*;
12521
12522	SFINAETrap(Sema &S, sema::TemplateDeductionInfo *Info,
12523	bool WithAccessChecking)
12524	: SFINAEContextBase (S, this), WithAccessChecking(WithAccessChecking),
12525	DeductionInfo(Info) {}
12526
12527	public:
12528	/// \param WithAccessChecking If true, discard all diagnostics (from the
12529	/// immediate context) instead of adding them to the currently active
12530	/// \ref TemplateDeductionInfo.
12531	explicit SFINAETrap(Sema &S, bool WithAccessChecking = false)
12532	: SFINAETrap (S, /Info=/nullptr, WithAccessChecking) {}
12533
12534	SFINAETrap(Sema &S, sema::TemplateDeductionInfo &Info)
12535	: SFINAETrap (S, &Info, /WithAccessChecking=/false) {}
12536
12537	~SFINAETrap() {
12538	S.getDiagnostics().setLastDiagnosticIgnored(PrevLastDiagnosticIgnored);
12539	}
12540
12541	SFINAETrap(const SFINAETrap &) = delete;
12542	SFINAETrap &operator=(const SFINAETrap &) = delete;
12543
12544	sema::TemplateDeductionInfo getDeductionInfo() const* {
12545	return DeductionInfo;
12546	}
12547
12548	/// Determine whether any SFINAE errors have been trapped.
12549	bool hasErrorOccurred() const { return HasErrorOcurred; }
12550	void setErrorOccurred() { HasErrorOcurred = true; }
12551
12552	bool withAccessChecking() const { return WithAccessChecking; }
12553	};
12554
12555	/// RAII class used to indicate that we are performing provisional
12556	/// semantic analysis to determine the validity of a construct, so
12557	/// typo-correction and diagnostics in the immediate context (not within
12558	/// implicitly-instantiated templates) should be suppressed.
12559	class TentativeAnalysisScope {
12560	Sema &SemaRef;
12561	// FIXME: Using a SFINAETrap for this is a hack.
12562	SFINAETrap Trap;
12563	bool PrevDisableTypoCorrection;
12564
12565	public:
12566	explicit TentativeAnalysisScope(Sema &SemaRef)
12567	: SemaRef(SemaRef), Trap (SemaRef, /ForValidityCheck=/true),
12568	PrevDisableTypoCorrection(SemaRef.DisableTypoCorrection) {
12569	SemaRef.DisableTypoCorrection = true;
12570	}
12571	~TentativeAnalysisScope() {
12572	SemaRef.DisableTypoCorrection = PrevDisableTypoCorrection;
12573	}
12574
12575	TentativeAnalysisScope(const TentativeAnalysisScope &) = delete;
12576	TentativeAnalysisScope &operator=(const TentativeAnalysisScope &) = delete;
12577	};
12578
12579	/// For each declaration that involved template argument deduction, the
12580	/// set of diagnostics that were suppressed during that template argument
12581	/// deduction.
12582	///
12583	/// FIXME: Serialize this structure to the AST file.
12584	typedef llvm::DenseMap<Decl *, SmallVector<PartialDiagnosticAt, `1`>>
12585	SuppressedDiagnosticsMap;
12586	SuppressedDiagnosticsMap SuppressedDiagnostics;
12587
12588	/// Compare types for equality with respect to possibly compatible
12589	/// function types (noreturn adjustment, implicit calling conventions). If any
12590	/// of parameter and argument is not a function, just perform type comparison.
12591	///
12592	/// \param P the template parameter type.
12593	///
12594	/// \param A the argument type.
12595	bool isSameOrCompatibleFunctionType(QualType Param, QualType Arg);
12596
12597	/// Allocate a TemplateArgumentLoc where all locations have
12598	/// been initialized to the given location.
12599	///
12600	/// \param Arg The template argument we are producing template argument
12601	/// location information for.
12602	///
12603	/// \param NTTPType For a declaration template argument, the type of
12604	/// the non-type template parameter that corresponds to this template
12605	/// argument. Can be null if no type sugar is available to add to the
12606	/// type from the template argument.
12607	///
12608	/// \param Loc The source location to use for the resulting template
12609	/// argument.
12610	TemplateArgumentLoc
12611	getTrivialTemplateArgumentLoc(const TemplateArgument &Arg, QualType NTTPType,
12612	SourceLocation Loc,
12613	NamedDecl TemplateParam = nullptr*);
12614
12615	/// Get a template argument mapping the given template parameter to itself,
12616	/// e.g. for X in \c template<int X>, this would return an expression template
12617	/// argument referencing X.
12618	TemplateArgumentLoc getIdentityTemplateArgumentLoc(NamedDecl *Param,
12619	SourceLocation Location);
12620
12621	/// Adjust the type \p ArgFunctionType to match the calling convention,
12622	/// noreturn, and optionally the exception specification of \p FunctionType.
12623	/// Deduction often wants to ignore these properties when matching function
12624	/// types.
12625	QualType adjustCCAndNoReturn(QualType ArgFunctionType, QualType FunctionType,
12626	bool AdjustExceptionSpec = false);
12627
12628	TemplateDeductionResult
12629	DeduceTemplateArguments(ClassTemplatePartialSpecializationDecl *Partial,
12630	ArrayRef<TemplateArgument> TemplateArgs,
12631	sema::TemplateDeductionInfo &Info);
12632
12633	TemplateDeductionResult
12634	DeduceTemplateArguments(VarTemplatePartialSpecializationDecl *Partial,
12635	ArrayRef<TemplateArgument> TemplateArgs,
12636	sema::TemplateDeductionInfo &Info);
12637
12638	/// Deduce the template arguments of the given template from \p FromType.
12639	/// Used to implement the IsDeducible constraint for alias CTAD per C++
12640	/// [over.match.class.deduct]p4.
12641	///
12642	/// It only supports class or type alias templates.
12643	TemplateDeductionResult
12644	DeduceTemplateArgumentsFromType(TemplateDecl *TD, QualType FromType,
12645	sema::TemplateDeductionInfo &Info);
12646
12647	TemplateDeductionResult DeduceTemplateArguments(
12648	TemplateParameterList *TemplateParams, ArrayRef<TemplateArgument> Ps,
12649	ArrayRef<TemplateArgument> As, sema::TemplateDeductionInfo &Info,
12650	SmallVectorImpl<DeducedTemplateArgument> &Deduced,
12651	bool NumberOfArgumentsMustMatch);
12652
12653	/// Substitute the explicitly-provided template arguments into the
12654	/// given function template according to C++ [temp.arg.explicit].
12655	///
12656	/// \param FunctionTemplate the function template into which the explicit
12657	/// template arguments will be substituted.
12658	///
12659	/// \param ExplicitTemplateArgs the explicitly-specified template
12660	/// arguments.
12661	///
12662	/// \param Deduced the deduced template arguments, which will be populated
12663	/// with the converted and checked explicit template arguments.
12664	///
12665	/// \param ParamTypes will be populated with the instantiated function
12666	/// parameters.
12667	///
12668	/// \param FunctionType if non-NULL, the result type of the function template
12669	/// will also be instantiated and the pointed-to value will be updated with
12670	/// the instantiated function type.
12671	///
12672	/// \param Info if substitution fails for any reason, this object will be
12673	/// populated with more information about the failure.
12674	///
12675	/// \returns TemplateDeductionResult::Success if substitution was successful,
12676	/// or some failure condition.
12677	TemplateDeductionResult SubstituteExplicitTemplateArguments(
12678	FunctionTemplateDecl *FunctionTemplate,
12679	TemplateArgumentListInfo &ExplicitTemplateArgs,
12680	SmallVectorImpl<DeducedTemplateArgument> &Deduced,
12681	SmallVectorImpl<QualType> &ParamTypes, QualType *FunctionType,
12682	sema::TemplateDeductionInfo &Info);
12683
12684	/// brief A function argument from which we performed template argument
12685	// deduction for a call.
12686	struct OriginalCallArg {
12687	OriginalCallArg(QualType OriginalParamType, bool DecomposedParam,
12688	unsigned ArgIdx, QualType OriginalArgType)
12689	: OriginalParamType (OriginalParamType),
12690	DecomposedParam(DecomposedParam), ArgIdx(ArgIdx),
12691	OriginalArgType (OriginalArgType) {}
12692
12693	QualType OriginalParamType;
12694	bool DecomposedParam;
12695	unsigned ArgIdx;
12696	QualType OriginalArgType;
12697	};
12698
12699	/// Finish template argument deduction for a function template,
12700	/// checking the deduced template arguments for completeness and forming
12701	/// the function template specialization.
12702	///
12703	/// \param OriginalCallArgs If non-NULL, the original call arguments against
12704	/// which the deduced argument types should be compared.
12705	/// \param CheckNonDependent Callback before substituting into the declaration
12706	/// with the deduced template arguments.
12707	/// \param OnlyInitializeNonUserDefinedConversions is used as a workaround for
12708	/// some breakages introduced by CWG2369, where non-user-defined conversions
12709	/// are checked first before the constraints.
12710	TemplateDeductionResult FinishTemplateArgumentDeduction(
12711	FunctionTemplateDecl *FunctionTemplate,
12712	SmallVectorImpl<DeducedTemplateArgument> &Deduced,
12713	unsigned NumExplicitlySpecified, FunctionDecl *&Specialization,
12714	sema::TemplateDeductionInfo &Info,
12715	SmallVectorImpl<OriginalCallArg> const *OriginalCallArgs,
12716	bool PartialOverloading, bool PartialOrdering,
12717	bool ForOverloadSetAddressResolution,
12718	llvm::function_ref<bool(bool)> CheckNonDependent =
12719	[](bool /OnlyInitializeNonUserDefinedConversions/) {
12720	return false;
12721	});
12722
12723	/// Perform template argument deduction from a function call
12724	/// (C++ [temp.deduct.call]).
12725	///
12726	/// \param FunctionTemplate the function template for which we are performing
12727	/// template argument deduction.
12728	///
12729	/// \param ExplicitTemplateArgs the explicit template arguments provided
12730	/// for this call.
12731	///
12732	/// \param Args the function call arguments
12733	///
12734	/// \param Specialization if template argument deduction was successful,
12735	/// this will be set to the function template specialization produced by
12736	/// template argument deduction.
12737	///
12738	/// \param Info the argument will be updated to provide additional information
12739	/// about template argument deduction.
12740	///
12741	/// \param CheckNonDependent A callback to invoke to check conversions for
12742	/// non-dependent parameters, between deduction and substitution, per DR1391.
12743	/// If this returns true, substitution will be skipped and we return
12744	/// TemplateDeductionResult::NonDependentConversionFailure. The callback is
12745	/// passed the parameter types (after substituting explicit template
12746	/// arguments).
12747	///
12748	/// \returns the result of template argument deduction.
12749	TemplateDeductionResult DeduceTemplateArguments(
12750	FunctionTemplateDecl *FunctionTemplate,
12751	TemplateArgumentListInfo ExplicitTemplateArgs, ArrayRef<Expr > Args,
12752	FunctionDecl *&Specialization, sema::TemplateDeductionInfo &Info,
12753	bool PartialOverloading, bool AggregateDeductionCandidate,
12754	bool PartialOrdering, QualType ObjectType,
12755	Expr::Classification ObjectClassification,
12756	bool ForOverloadSetAddressResolution,
12757	llvm::function_ref<bool(ArrayRef<QualType>, bool)> CheckNonDependent);
12758
12759	/// Deduce template arguments when taking the address of a function
12760	/// template (C++ [temp.deduct.funcaddr]) or matching a specialization to
12761	/// a template.
12762	///
12763	/// \param FunctionTemplate the function template for which we are performing
12764	/// template argument deduction.
12765	///
12766	/// \param ExplicitTemplateArgs the explicitly-specified template
12767	/// arguments.
12768	///
12769	/// \param ArgFunctionType the function type that will be used as the
12770	/// "argument" type (A) when performing template argument deduction from the
12771	/// function template's function type. This type may be NULL, if there is no
12772	/// argument type to compare against, in C++0x [temp.arg.explicit]p3.
12773	///
12774	/// \param Specialization if template argument deduction was successful,
12775	/// this will be set to the function template specialization produced by
12776	/// template argument deduction.
12777	///
12778	/// \param Info the argument will be updated to provide additional information
12779	/// about template argument deduction.
12780	///
12781	/// \param IsAddressOfFunction If \c true, we are deducing as part of taking
12782	/// the address of a function template per [temp.deduct.funcaddr] and
12783	/// [over.over]. If \c false, we are looking up a function template
12784	/// specialization based on its signature, per [temp.deduct.decl].
12785	///
12786	/// \returns the result of template argument deduction.
12787	TemplateDeductionResult DeduceTemplateArguments(
12788	FunctionTemplateDecl *FunctionTemplate,
12789	TemplateArgumentListInfo *ExplicitTemplateArgs, QualType ArgFunctionType,
12790	FunctionDecl *&Specialization, sema::TemplateDeductionInfo &Info,
12791	bool IsAddressOfFunction = false);
12792
12793	/// Deduce template arguments for a templated conversion
12794	/// function (C++ [temp.deduct.conv]) and, if successful, produce a
12795	/// conversion function template specialization.
12796	TemplateDeductionResult DeduceTemplateArguments(
12797	FunctionTemplateDecl *FunctionTemplate, QualType ObjectType,
12798	Expr::Classification ObjectClassification, QualType ToType,
12799	CXXConversionDecl *&Specialization, sema::TemplateDeductionInfo &Info);
12800
12801	/// Deduce template arguments for a function template when there is
12802	/// nothing to deduce against (C++0x [temp.arg.explicit]p3).
12803	///
12804	/// \param FunctionTemplate the function template for which we are performing
12805	/// template argument deduction.
12806	///
12807	/// \param ExplicitTemplateArgs the explicitly-specified template
12808	/// arguments.
12809	///
12810	/// \param Specialization if template argument deduction was successful,
12811	/// this will be set to the function template specialization produced by
12812	/// template argument deduction.
12813	///
12814	/// \param Info the argument will be updated to provide additional information
12815	/// about template argument deduction.
12816	///
12817	/// \param IsAddressOfFunction If \c true, we are deducing as part of taking
12818	/// the address of a function template in a context where we do not have a
12819	/// target type, per [over.over]. If \c false, we are looking up a function
12820	/// template specialization based on its signature, which only happens when
12821	/// deducing a function parameter type from an argument that is a template-id
12822	/// naming a function template specialization.
12823	///
12824	/// \returns the result of template argument deduction.
12825	TemplateDeductionResult
12826	DeduceTemplateArguments(FunctionTemplateDecl *FunctionTemplate,
12827	TemplateArgumentListInfo *ExplicitTemplateArgs,
12828	FunctionDecl *&Specialization,
12829	sema::TemplateDeductionInfo &Info,
12830	bool IsAddressOfFunction = false);
12831
12832	/// Substitute Replacement for \p auto in \p TypeWithAuto
12833	QualType SubstAutoType(QualType TypeWithAuto, QualType Replacement);
12834	/// Substitute Replacement for auto in TypeWithAuto
12835	TypeSourceInfo SubstAutoTypeSourceInfo(TypeSourceInfo TypeWithAuto,
12836	QualType Replacement);
12837
12838	// Substitute auto in TypeWithAuto for a Dependent auto type
12839	QualType SubstAutoTypeDependent(QualType TypeWithAuto);
12840
12841	// Substitute auto in TypeWithAuto for a Dependent auto type
12842	TypeSourceInfo *
12843	SubstAutoTypeSourceInfoDependent(TypeSourceInfo *TypeWithAuto);
12844
12845	/// Completely replace the \c auto in \p TypeWithAuto by
12846	/// \p Replacement. This does not retain any \c auto type sugar.
12847	QualType ReplaceAutoType(QualType TypeWithAuto, QualType Replacement);
12848	TypeSourceInfo ReplaceAutoTypeSourceInfo(TypeSourceInfo TypeWithAuto,
12849	QualType Replacement);
12850
12851	/// Deduce the type for an auto type-specifier (C++11 [dcl.spec.auto]p6)
12852	///
12853	/// Note that this is done even if the initializer is dependent. (This is
12854	/// necessary to support partial ordering of templates using 'auto'.)
12855	/// A dependent type will be produced when deducing from a dependent type.
12856	///
12857	/// \param Type the type pattern using the auto type-specifier.
12858	/// \param Init the initializer for the variable whose type is to be deduced.
12859	/// \param Result if type deduction was successful, this will be set to the
12860	/// deduced type.
12861	/// \param Info the argument will be updated to provide additional information
12862	/// about template argument deduction.
12863	/// \param DependentDeduction Set if we should permit deduction in
12864	/// dependent cases. This is necessary for template partial ordering
12865	/// with 'auto' template parameters. The template parameter depth to be
12866	/// used should be specified in the 'Info' parameter.
12867	/// \param IgnoreConstraints Set if we should not fail if the deduced type
12868	/// does not satisfy the type-constraint in the auto
12869	/// type.
12870	TemplateDeductionResult
12871	DeduceAutoType(TypeLoc AutoTypeLoc, Expr *Initializer, QualType &Result,
12872	sema::TemplateDeductionInfo &Info,
12873	bool DependentDeduction = false,
12874	bool IgnoreConstraints = false,
12875	TemplateSpecCandidateSet FailedTSC = nullptr*);
12876	void DiagnoseAutoDeductionFailure(const VarDecl VDecl, const* Expr *Init);
12877	bool DeduceReturnType(FunctionDecl *FD, SourceLocation Loc,
12878	bool Diagnose = true);
12879
12880	bool CheckIfFunctionSpecializationIsImmediate(FunctionDecl *FD,
12881	SourceLocation Loc);
12882
12883	/// Returns the more specialized class template partial specialization
12884	/// according to the rules of partial ordering of class template partial
12885	/// specializations (C++ [temp.class.order]).
12886	///
12887	/// \param PS1 the first class template partial specialization
12888	///
12889	/// \param PS2 the second class template partial specialization
12890	///
12891	/// \returns the more specialized class template partial specialization. If
12892	/// neither partial specialization is more specialized, returns NULL.
12893	ClassTemplatePartialSpecializationDecl *
12894	getMoreSpecializedPartialSpecialization(
12895	ClassTemplatePartialSpecializationDecl *PS1,
12896	ClassTemplatePartialSpecializationDecl *PS2, SourceLocation Loc);
12897
12898	bool isMoreSpecializedThanPrimary(ClassTemplatePartialSpecializationDecl *T,
12899	sema::TemplateDeductionInfo &Info);
12900
12901	VarTemplatePartialSpecializationDecl *getMoreSpecializedPartialSpecialization(
12902	VarTemplatePartialSpecializationDecl *PS1,
12903	VarTemplatePartialSpecializationDecl *PS2, SourceLocation Loc);
12904
12905	bool isMoreSpecializedThanPrimary(VarTemplatePartialSpecializationDecl *T,
12906	sema::TemplateDeductionInfo &Info);
12907
12908	bool isTemplateTemplateParameterAtLeastAsSpecializedAs(
12909	TemplateParameterList PParam, TemplateDecl PArg, TemplateDecl *AArg,
12910	const DefaultArguments &DefaultArgs, SourceLocation ArgLoc,
12911	bool PartialOrdering, bool *StrictPackMatch);
12912
12913	/// Mark which template parameters are used in a given expression.
12914	///
12915	/// \param E the expression from which template parameters will be deduced.
12916	///
12917	/// \param Used a bit vector whose elements will be set to \c true
12918	/// to indicate when the corresponding template parameter will be
12919	/// deduced.
12920	void MarkUsedTemplateParameters(const Expr E, bool* OnlyDeduced,
12921	unsigned Depth, llvm::SmallBitVector &Used);
12922
12923	/// Mark which template parameters are named in a given expression.
12924	///
12925	/// Unlike MarkUsedTemplateParameters, this excludes parameter that
12926	/// are used but not directly named by an expression - i.e. it excludes
12927	/// any template parameter that denotes the type of a referenced NTTP.
12928	///
12929	/// \param Used a bit vector whose elements will be set to \c true
12930	/// to indicate when the corresponding template parameter will be
12931	/// deduced.
12932	void MarkUsedTemplateParametersForSubsumptionParameterMapping(
12933	const Expr E, unsigned* Depth, llvm::SmallBitVector &Used);
12934
12935	/// Mark which template parameters can be deduced from a given
12936	/// template argument list.
12937	///
12938	/// \param TemplateArgs the template argument list from which template
12939	/// parameters will be deduced.
12940	///
12941	/// \param Used a bit vector whose elements will be set to \c true
12942	/// to indicate when the corresponding template parameter will be
12943	/// deduced.
12944	void MarkUsedTemplateParameters(const TemplateArgumentList &TemplateArgs,
12945	bool OnlyDeduced, unsigned Depth,
12946	llvm::SmallBitVector &Used);
12947
12948	void MarkUsedTemplateParameters(ArrayRef<TemplateArgument> TemplateArgs,
12949	unsigned Depth, llvm::SmallBitVector &Used);
12950
12951	void MarkUsedTemplateParameters(ArrayRef<TemplateArgumentLoc> TemplateArgs,
12952	unsigned Depth, llvm::SmallBitVector &Used);
12953
12954	void
12955	MarkDeducedTemplateParameters(const FunctionTemplateDecl *FunctionTemplate,
12956	llvm::SmallBitVector &Deduced) {
12957	return MarkDeducedTemplateParameters(Ctx&: Context, FunctionTemplate, Deduced);
12958	}
12959
12960	/// Marks all of the template parameters that will be deduced by a
12961	/// call to the given function template.
12962	static void
12963	MarkDeducedTemplateParameters(ASTContext &Ctx,
12964	const FunctionTemplateDecl *FunctionTemplate,
12965	llvm::SmallBitVector &Deduced);
12966
12967	/// Returns the more specialized function template according
12968	/// to the rules of function template partial ordering (C++
12969	/// [temp.func.order]).
12970	///
12971	/// \param FT1 the first function template
12972	///
12973	/// \param FT2 the second function template
12974	///
12975	/// \param TPOC the context in which we are performing partial ordering of
12976	/// function templates.
12977	///
12978	/// \param NumCallArguments1 The number of arguments in the call to FT1, used
12979	/// only when \c TPOC is \c TPOC_Call. Does not include the object argument
12980	/// when calling a member function.
12981	///
12982	/// \param RawObj1Ty The type of the object parameter of FT1 if a member
12983	/// function only used if \c TPOC is \c TPOC_Call and FT1 is a Function
12984	/// template from a member function
12985	///
12986	/// \param RawObj2Ty The type of the object parameter of FT2 if a member
12987	/// function only used if \c TPOC is \c TPOC_Call and FT2 is a Function
12988	/// template from a member function
12989	///
12990	/// \param Reversed If \c true, exactly one of FT1 and FT2 is an overload
12991	/// candidate with a reversed parameter order. In this case, the corresponding
12992	/// P/A pairs between FT1 and FT2 are reversed.
12993	///
12994	/// \returns the more specialized function template. If neither
12995	/// template is more specialized, returns NULL.
12996	FunctionTemplateDecl *getMoreSpecializedTemplate(
12997	FunctionTemplateDecl FT1, FunctionTemplateDecl FT2, SourceLocation Loc,
12998	TemplatePartialOrderingContext TPOC, unsigned NumCallArguments1,
12999	QualType RawObj1Ty = {}, QualType RawObj2Ty = {}, bool Reversed = false,
13000	bool PartialOverloading = false);
13001
13002	/// Retrieve the most specialized of the given function template
13003	/// specializations.
13004	///
13005	/// \param SpecBegin the start iterator of the function template
13006	/// specializations that we will be comparing.
13007	///
13008	/// \param SpecEnd the end iterator of the function template
13009	/// specializations, paired with \p SpecBegin.
13010	///
13011	/// \param Loc the location where the ambiguity or no-specializations
13012	/// diagnostic should occur.
13013	///
13014	/// \param NoneDiag partial diagnostic used to diagnose cases where there are
13015	/// no matching candidates.
13016	///
13017	/// \param AmbigDiag partial diagnostic used to diagnose an ambiguity, if one
13018	/// occurs.
13019	///
13020	/// \param CandidateDiag partial diagnostic used for each function template
13021	/// specialization that is a candidate in the ambiguous ordering. One
13022	/// parameter in this diagnostic should be unbound, which will correspond to
13023	/// the string describing the template arguments for the function template
13024	/// specialization.
13025	///
13026	/// \returns the most specialized function template specialization, if
13027	/// found. Otherwise, returns SpecEnd.
13028	UnresolvedSetIterator
13029	getMostSpecialized(UnresolvedSetIterator SBegin, UnresolvedSetIterator SEnd,
13030	TemplateSpecCandidateSet &FailedCandidates,
13031	SourceLocation Loc, const PartialDiagnostic &NoneDiag,
13032	const PartialDiagnostic &AmbigDiag,
13033	const PartialDiagnostic &CandidateDiag,
13034	bool Complain = true, QualType TargetType = QualType ());
13035
13036	/// Returns the more constrained function according to the rules of
13037	/// partial ordering by constraints (C++ [temp.constr.order]).
13038	///
13039	/// \param FD1 the first function
13040	///
13041	/// \param FD2 the second function
13042	///
13043	/// \returns the more constrained function. If neither function is
13044	/// more constrained, returns NULL.
13045	FunctionDecl getMoreConstrainedFunction(FunctionDecl FD1,
13046	FunctionDecl *FD2);
13047
13048	///@}
13049
13050	//
13051	//
13052	// -------------------------------------------------------------------------
13053	//
13054	//
13055
13056	/// \name C++ Template Deduction Guide
13057	/// Implementations are in SemaTemplateDeductionGuide.cpp
13058	///@{
13059
13060	/// Declare implicit deduction guides for a class template if we've
13061	/// not already done so.
13062	void DeclareImplicitDeductionGuides(TemplateDecl *Template,
13063	SourceLocation Loc);
13064
13065	FunctionTemplateDecl *DeclareAggregateDeductionGuideFromInitList(
13066	TemplateDecl *Template, MutableArrayRef<QualType> ParamTypes,
13067	SourceLocation Loc);
13068
13069	///@}
13070
13071	//
13072	//
13073	// -------------------------------------------------------------------------
13074	//
13075	//
13076
13077	/// \name C++ Template Instantiation
13078	/// Implementations are in SemaTemplateInstantiate.cpp
13079	///@{
13080
13081	public:
13082	/// A helper class for building up ExtParameterInfos.
13083	class ExtParameterInfoBuilder {
13084	SmallVector<FunctionProtoType::ExtParameterInfo, `16`> Infos;
13085	bool HasInteresting = false;
13086
13087	public:
13088	/// Set the ExtParameterInfo for the parameter at the given index,
13089	///
13090	void set(unsigned index, FunctionProtoType::ExtParameterInfo info) {
13091	assert(Infos.size() <= index);
13092	Infos.resize(N: index);
13093	Infos.push_back(Elt: info);
13094
13095	if (!HasInteresting)
13096	HasInteresting = (info != FunctionProtoType::ExtParameterInfo ());
13097	}
13098
13099	/// Return a pointer (suitable for setting in an ExtProtoInfo) to the
13100	/// ExtParameterInfo array we've built up.
13101	const FunctionProtoType::ExtParameterInfo *
13102	getPointerOrNull(unsigned numParams) {
13103	if (!HasInteresting)
13104	return nullptr;
13105	Infos.resize(N: numParams);
13106	return Infos.data();
13107	}
13108	};
13109
13110	/// The current instantiation scope used to store local
13111	/// variables.
13112	LocalInstantiationScope *CurrentInstantiationScope;
13113
13114	typedef llvm::DenseMap<ParmVarDecl , llvm::TinyPtrVector<ParmVarDecl >>
13115	UnparsedDefaultArgInstantiationsMap;
13116
13117	/// A mapping from parameters with unparsed default arguments to the
13118	/// set of instantiations of each parameter.
13119	///
13120	/// This mapping is a temporary data structure used when parsing
13121	/// nested class templates or nested classes of class templates,
13122	/// where we might end up instantiating an inner class before the
13123	/// default arguments of its methods have been parsed.
13124	UnparsedDefaultArgInstantiationsMap UnparsedDefaultArgInstantiations;
13125
13126	using InstantiatingSpecializationsKey = llvm::PointerIntPair<Decl *, `2`>;
13127
13128	struct RecursiveInstGuard {
13129	enum class Kind {
13130	Template,
13131	DefaultArgument,
13132	ExceptionSpec,
13133	};
13134
13135	RecursiveInstGuard(Sema &S, Decl *D, Kind Kind)
13136	: S(S), Key (D->getCanonicalDecl(), unsigned(Kind)) {
13137	auto [_, Created] = S.InstantiatingSpecializations.insert(V: Key);
13138	if (!Created)
13139	Key = {};
13140	}
13141
13142	~RecursiveInstGuard() {
13143	if (Key.getOpaqueValue()) {
13144	[[maybe_unused]] bool Erased =
13145	S.InstantiatingSpecializations.erase(V: Key);
13146	assert(Erased);
13147	}
13148	}
13149
13150	RecursiveInstGuard(const RecursiveInstGuard &) = delete;
13151	RecursiveInstGuard &operator=(const RecursiveInstGuard &) = delete;
13152
13153	operator bool() const { return Key.getOpaqueValue() == nullptr; }
13154
13155	private:
13156	Sema &S;
13157	Sema::InstantiatingSpecializationsKey Key;
13158	};
13159
13160	/// A context in which code is being synthesized (where a source location
13161	/// alone is not sufficient to identify the context). This covers template
13162	/// instantiation and various forms of implicitly-generated functions.
13163	struct CodeSynthesisContext {
13164	/// The kind of template instantiation we are performing
13165	enum SynthesisKind {
13166	/// We are instantiating a template declaration. The entity is
13167	/// the declaration we're instantiating (e.g., a CXXRecordDecl).
13168	TemplateInstantiation,
13169
13170	/// We are instantiating a default argument for a template
13171	/// parameter. The Entity is the template parameter whose argument is
13172	/// being instantiated, the Template is the template, and the
13173	/// TemplateArgs/NumTemplateArguments provide the template arguments as
13174	/// specified.
13175	DefaultTemplateArgumentInstantiation,
13176
13177	/// We are instantiating a default argument for a function.
13178	/// The Entity is the ParmVarDecl, and TemplateArgs/NumTemplateArgs
13179	/// provides the template arguments as specified.
13180	DefaultFunctionArgumentInstantiation,
13181
13182	/// We are substituting explicit template arguments provided for
13183	/// a function template. The entity is a FunctionTemplateDecl.
13184	ExplicitTemplateArgumentSubstitution,
13185
13186	/// We are substituting template argument determined as part of
13187	/// template argument deduction for either a class template
13188	/// partial specialization or a function template. The
13189	/// Entity is either a {Class\|Var}TemplatePartialSpecializationDecl or
13190	/// a TemplateDecl.
13191	DeducedTemplateArgumentSubstitution,
13192
13193	/// We are substituting into a lambda expression.
13194	LambdaExpressionSubstitution,
13195
13196	/// We are substituting prior template arguments into a new
13197	/// template parameter. The template parameter itself is either a
13198	/// NonTypeTemplateParmDecl or a TemplateTemplateParmDecl.
13199	PriorTemplateArgumentSubstitution,
13200
13201	/// We are checking the validity of a default template argument that
13202	/// has been used when naming a template-id.
13203	DefaultTemplateArgumentChecking,
13204
13205	/// We are computing the exception specification for a defaulted special
13206	/// member function.
13207	ExceptionSpecEvaluation,
13208
13209	/// We are instantiating the exception specification for a function
13210	/// template which was deferred until it was needed.
13211	ExceptionSpecInstantiation,
13212
13213	/// We are instantiating a requirement of a requires expression.
13214	RequirementInstantiation,
13215
13216	/// We are checking the satisfaction of a nested requirement of a requires
13217	/// expression.
13218	NestedRequirementConstraintsCheck,
13219
13220	/// We are declaring an implicit special member function.
13221	DeclaringSpecialMember,
13222
13223	/// We are declaring an implicit 'operator==' for a defaulted
13224	/// 'operator<=>'.
13225	DeclaringImplicitEqualityComparison,
13226
13227	/// We are defining a synthesized function (such as a defaulted special
13228	/// member).
13229	DefiningSynthesizedFunction,
13230
13231	// We are checking the constraints associated with a constrained entity or
13232	// the constraint expression of a concept. This includes the checks that
13233	// atomic constraints have the type 'bool' and that they can be constant
13234	// evaluated.
13235	ConstraintsCheck,
13236
13237	// We are substituting template arguments into a constraint expression.
13238	ConstraintSubstitution,
13239
13240	// We are normalizing a constraint expression.
13241	ConstraintNormalization,
13242
13243	// Instantiating a Requires Expression parameter clause.
13244	RequirementParameterInstantiation,
13245
13246	// We are substituting into the parameter mapping of an atomic constraint
13247	// during normalization.
13248	ParameterMappingSubstitution,
13249
13250	/// We are rewriting a comparison operator in terms of an operator<=>.
13251	RewritingOperatorAsSpaceship,
13252
13253	/// We are initializing a structured binding.
13254	InitializingStructuredBinding,
13255
13256	/// We are marking a class as __dllexport.
13257	MarkingClassDllexported,
13258
13259	/// We are building an implied call from __builtin_dump_struct. The
13260	/// arguments are in CallArgs.
13261	BuildingBuiltinDumpStructCall,
13262
13263	/// Added for Template instantiation observation.
13264	/// Memoization means we are _not_ instantiating a template because
13265	/// it is already instantiated (but we entered a context where we
13266	/// would have had to if it was not already instantiated).
13267	Memoization,
13268
13269	/// We are building deduction guides for a class.
13270	BuildingDeductionGuides,
13271
13272	/// We are instantiating a type alias template declaration.
13273	TypeAliasTemplateInstantiation,
13274
13275	/// We are performing partial ordering for template template parameters.
13276	PartialOrderingTTP,
13277	} Kind;
13278
13279	/// Whether we're substituting into constraints.
13280	bool InConstraintSubstitution;
13281
13282	/// Whether we're substituting into the parameter mapping of a constraint.
13283	bool InParameterMappingSubstitution;
13284
13285	/// The point of instantiation or synthesis within the source code.
13286	SourceLocation PointOfInstantiation;
13287
13288	/// The entity that is being synthesized.
13289	Decl *Entity;
13290
13291	/// The template (or partial specialization) in which we are
13292	/// performing the instantiation, for substitutions of prior template
13293	/// arguments.
13294	NamedDecl *Template;
13295
13296	union {
13297	/// The list of template arguments we are substituting, if they
13298	/// are not part of the entity.
13299	const TemplateArgument *TemplateArgs;
13300
13301	/// The list of argument expressions in a synthesized call.
13302	const Expr *const *CallArgs;
13303	};
13304
13305	// FIXME: Wrap this union around more members, or perhaps store the
13306	// kind-specific members in the RAII object owning the context.
13307	union {
13308	/// The number of template arguments in TemplateArgs.
13309	unsigned NumTemplateArgs;
13310
13311	/// The number of expressions in CallArgs.
13312	unsigned NumCallArgs;
13313
13314	/// The special member being declared or defined.
13315	CXXSpecialMemberKind SpecialMember;
13316	};
13317
13318	ArrayRef<TemplateArgument> template_arguments() const {
13319	assert(Kind != DeclaringSpecialMember);
13320	return {TemplateArgs, NumTemplateArgs};
13321	}
13322
13323	/// The source range that covers the construct that cause
13324	/// the instantiation, e.g., the template-id that causes a class
13325	/// template instantiation.
13326	SourceRange InstantiationRange;
13327
13328	CodeSynthesisContext()
13329	: Kind(TemplateInstantiation), InConstraintSubstitution(false),
13330	InParameterMappingSubstitution(false), Entity(nullptr),
13331	Template(nullptr), TemplateArgs(nullptr), NumTemplateArgs(`0`) {}
13332
13333	/// Determines whether this template is an actual instantiation
13334	/// that should be counted toward the maximum instantiation depth.
13335	bool isInstantiationRecord() const;
13336	};
13337
13338	/// A stack object to be created when performing template
13339	/// instantiation.
13340	///
13341	/// Construction of an object of type \c InstantiatingTemplate
13342	/// pushes the current instantiation onto the stack of active
13343	/// instantiations. If the size of this stack exceeds the maximum
13344	/// number of recursive template instantiations, construction
13345	/// produces an error and evaluates true.
13346	///
13347	/// Destruction of this object will pop the named instantiation off
13348	/// the stack.
13349	struct InstantiatingTemplate {
13350	/// Note that we are instantiating a class template,
13351	/// function template, variable template, alias template,
13352	/// or a member thereof.
13353	InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
13354	Decl *Entity,
13355	SourceRange InstantiationRange = SourceRange ());
13356
13357	struct ExceptionSpecification {};
13358	/// Note that we are instantiating an exception specification
13359	/// of a function template.
13360	InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
13361	FunctionDecl *Entity, ExceptionSpecification,
13362	SourceRange InstantiationRange = SourceRange ());
13363
13364	/// Note that we are instantiating a type alias template declaration.
13365	InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
13366	TypeAliasTemplateDecl *Entity,
13367	ArrayRef<TemplateArgument> TemplateArgs,
13368	SourceRange InstantiationRange = SourceRange ());
13369
13370	/// Note that we are instantiating a default argument in a
13371	/// template-id.
13372	InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
13373	TemplateParameter Param, TemplateDecl *Template,
13374	ArrayRef<TemplateArgument> TemplateArgs,
13375	SourceRange InstantiationRange = SourceRange ());
13376
13377	/// Note that we are substituting either explicitly-specified or
13378	/// deduced template arguments during function template argument deduction.
13379	InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
13380	FunctionTemplateDecl *FunctionTemplate,
13381	ArrayRef<TemplateArgument> TemplateArgs,
13382	CodeSynthesisContext::SynthesisKind Kind,
13383	SourceRange InstantiationRange = SourceRange ());
13384
13385	/// Note that we are instantiating as part of template
13386	/// argument deduction for a class template declaration.
13387	InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
13388	TemplateDecl *Template,
13389	ArrayRef<TemplateArgument> TemplateArgs,
13390	SourceRange InstantiationRange = SourceRange ());
13391
13392	/// Note that we are instantiating as part of template
13393	/// argument deduction for a class template partial
13394	/// specialization.
13395	InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
13396	ClassTemplatePartialSpecializationDecl *PartialSpec,
13397	ArrayRef<TemplateArgument> TemplateArgs,
13398	SourceRange InstantiationRange = SourceRange ());
13399
13400	/// Note that we are instantiating as part of template
13401	/// argument deduction for a variable template partial
13402	/// specialization.
13403	InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
13404	VarTemplatePartialSpecializationDecl *PartialSpec,
13405	ArrayRef<TemplateArgument> TemplateArgs,
13406	SourceRange InstantiationRange = SourceRange ());
13407
13408	/// Note that we are instantiating a default argument for a function
13409	/// parameter.
13410	InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
13411	ParmVarDecl *Param,
13412	ArrayRef<TemplateArgument> TemplateArgs,
13413	SourceRange InstantiationRange = SourceRange ());
13414
13415	/// Note that we are substituting prior template arguments into a
13416	/// non-type parameter.
13417	InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
13418	NamedDecl Template, NonTypeTemplateParmDecl Param,
13419	ArrayRef<TemplateArgument> TemplateArgs,
13420	SourceRange InstantiationRange);
13421
13422	/// Note that we are substituting prior template arguments into a
13423	/// template template parameter.
13424	InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
13425	NamedDecl Template, TemplateTemplateParmDecl Param,
13426	ArrayRef<TemplateArgument> TemplateArgs,
13427	SourceRange InstantiationRange);
13428
13429	/// Note that we are checking the default template argument
13430	/// against the template parameter for a given template-id.
13431	InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
13432	TemplateDecl Template, NamedDecl Param,
13433	ArrayRef<TemplateArgument> TemplateArgs,
13434	SourceRange InstantiationRange);
13435
13436	struct ConstraintsCheck {};
13437	/// \brief Note that we are checking the constraints associated with some
13438	/// constrained entity (a concept declaration or a template with associated
13439	/// constraints).
13440	InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
13441	ConstraintsCheck, NamedDecl *Template,
13442	ArrayRef<TemplateArgument> TemplateArgs,
13443	SourceRange InstantiationRange);
13444
13445	struct ConstraintSubstitution {};
13446	/// \brief Note that we are checking a constraint expression associated
13447	/// with a template declaration or as part of the satisfaction check of a
13448	/// concept.
13449	InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
13450	ConstraintSubstitution, NamedDecl *Template,
13451	SourceRange InstantiationRange);
13452
13453	struct ConstraintNormalization {};
13454	/// \brief Note that we are normalizing a constraint expression.
13455	InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
13456	ConstraintNormalization, NamedDecl *Template,
13457	SourceRange InstantiationRange);
13458
13459	struct ParameterMappingSubstitution {};
13460	/// \brief Note that we are subtituting into the parameter mapping of an
13461	/// atomic constraint during constraint normalization.
13462	InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
13463	ParameterMappingSubstitution, NamedDecl *Template,
13464	SourceRange InstantiationRange);
13465
13466	/// \brief Note that we are substituting template arguments into a part of
13467	/// a requirement of a requires expression.
13468	InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
13469	concepts::Requirement *Req,
13470	SourceRange InstantiationRange = SourceRange ());
13471
13472	/// \brief Note that we are checking the satisfaction of the constraint
13473	/// expression inside of a nested requirement.
13474	InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
13475	concepts::NestedRequirement *Req, ConstraintsCheck,
13476	SourceRange InstantiationRange = SourceRange ());
13477
13478	/// \brief Note that we are checking a requires clause.
13479	InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
13480	const RequiresExpr *E,
13481	SourceRange InstantiationRange);
13482
13483	struct BuildingDeductionGuidesTag {};
13484	/// \brief Note that we are building deduction guides.
13485	InstantiatingTemplate(Sema &SemaRef, SourceLocation PointOfInstantiation,
13486	TemplateDecl *Entity, BuildingDeductionGuidesTag,
13487	SourceRange InstantiationRange = SourceRange ());
13488
13489	struct PartialOrderingTTP {};
13490	/// \brief Note that we are partial ordering template template parameters.
13491	InstantiatingTemplate(Sema &SemaRef, SourceLocation ArgLoc,
13492	PartialOrderingTTP, TemplateDecl *PArg,
13493	SourceRange InstantiationRange = SourceRange ());
13494
13495	/// Note that we have finished instantiating this template.
13496	void Clear();
13497
13498	~InstantiatingTemplate() { Clear(); }
13499
13500	/// Determines whether we have exceeded the maximum
13501	/// recursive template instantiations.
13502	bool isInvalid() const { return Invalid; }
13503
13504	private:
13505	Sema &SemaRef;
13506	bool Invalid;
13507
13508	InstantiatingTemplate(Sema &SemaRef,
13509	CodeSynthesisContext::SynthesisKind Kind,
13510	SourceLocation PointOfInstantiation,
13511	SourceRange InstantiationRange, Decl *Entity,
13512	NamedDecl Template = nullptr*,
13513	ArrayRef<TemplateArgument> TemplateArgs = {});
13514
13515	InstantiatingTemplate(const InstantiatingTemplate &) = delete;
13516
13517	InstantiatingTemplate &operator=(const InstantiatingTemplate &) = delete;
13518	};
13519
13520	bool SubstTemplateArgument(const TemplateArgumentLoc &Input,
13521	const MultiLevelTemplateArgumentList &TemplateArgs,
13522	TemplateArgumentLoc &Output,
13523	SourceLocation Loc = {},
13524	const DeclarationName &Entity = {});
13525	bool
13526	SubstTemplateArguments(ArrayRef<TemplateArgumentLoc> Args,
13527	const MultiLevelTemplateArgumentList &TemplateArgs,
13528	TemplateArgumentListInfo &Outputs);
13529
13530	/// Substitute concept template arguments in the constraint expression
13531	/// of a concept-id. This is used to implement [temp.constr.normal].
13532	ExprResult
13533	SubstConceptTemplateArguments(const ConceptSpecializationExpr *CSE,
13534	const Expr *ConstraintExpr,
13535	const MultiLevelTemplateArgumentList &MLTAL);
13536
13537	bool SubstTemplateArgumentsInParameterMapping(
13538	ArrayRef<TemplateArgumentLoc> Args, SourceLocation BaseLoc,
13539	const MultiLevelTemplateArgumentList &TemplateArgs,
13540	TemplateArgumentListInfo &Out);
13541
13542	/// Retrieve the template argument list(s) that should be used to
13543	/// instantiate the definition of the given declaration.
13544	///
13545	/// \param ND the declaration for which we are computing template
13546	/// instantiation arguments.
13547	///
13548	/// \param DC In the event we don't HAVE a declaration yet, we instead provide
13549	/// the decl context where it will be created. In this case, the `Innermost`
13550	/// should likely be provided. If ND is non-null, this is ignored.
13551	///
13552	/// \param Innermost if non-NULL, specifies a template argument list for the
13553	/// template declaration passed as ND.
13554	///
13555	/// \param RelativeToPrimary true if we should get the template
13556	/// arguments relative to the primary template, even when we're
13557	/// dealing with a specialization. This is only relevant for function
13558	/// template specializations.
13559	///
13560	/// \param Pattern If non-NULL, indicates the pattern from which we will be
13561	/// instantiating the definition of the given declaration, \p ND. This is
13562	/// used to determine the proper set of template instantiation arguments for
13563	/// friend function template specializations.
13564	///
13565	/// \param ForConstraintInstantiation when collecting arguments,
13566	/// ForConstraintInstantiation indicates we should continue looking when
13567	/// encountering a lambda generic call operator, and continue looking for
13568	/// arguments on an enclosing class template.
13569	///
13570	/// \param SkipForSpecialization when specified, any template specializations
13571	/// in a traversal would be ignored.
13572	///
13573	/// \param ForDefaultArgumentSubstitution indicates we should continue looking
13574	/// when encountering a specialized member function template, rather than
13575	/// returning immediately.
13576	MultiLevelTemplateArgumentList getTemplateInstantiationArgs(
13577	const NamedDecl D, const* DeclContext DC = nullptr, bool* Final = false,
13578	std::optional<ArrayRef<TemplateArgument>> Innermost = std::nullopt,
13579	bool RelativeToPrimary = false, const FunctionDecl Pattern = nullptr*,
13580	bool ForConstraintInstantiation = false,
13581	bool SkipForSpecialization = false,
13582	bool ForDefaultArgumentSubstitution = false);
13583
13584	/// RAII object to handle the state changes required to synthesize
13585	/// a function body.
13586	class SynthesizedFunctionScope {
13587	Sema &S;
13588	Sema::ContextRAII SavedContext;
13589	bool PushedCodeSynthesisContext = false;
13590
13591	public:
13592	SynthesizedFunctionScope(Sema &S, DeclContext *DC)
13593	: S(S), SavedContext (S, DC) {
13594	auto *FD = dyn_cast<FunctionDecl>(Val: DC);
13595	S.PushFunctionScope();
13596	S.PushExpressionEvaluationContextForFunction(
13597	NewContext: ExpressionEvaluationContext::PotentiallyEvaluated, FD);
13598	if (FD)
13599	FD->setWillHaveBody(true);
13600	else
13601	assert(isa<ObjCMethodDecl>(DC));
13602	}
13603
13604	void addContextNote(SourceLocation UseLoc) {
13605	assert(!PushedCodeSynthesisContext);
13606
13607	Sema::CodeSynthesisContext Ctx;
13608	Ctx.Kind = Sema::CodeSynthesisContext::DefiningSynthesizedFunction;
13609	Ctx.PointOfInstantiation = UseLoc;
13610	Ctx.Entity = cast<Decl>(Val: S.CurContext);
13611	S.pushCodeSynthesisContext(Ctx);
13612
13613	PushedCodeSynthesisContext = true;
13614	}
13615
13616	~SynthesizedFunctionScope() {
13617	if (PushedCodeSynthesisContext)
13618	S.popCodeSynthesisContext();
13619	if (auto *FD = dyn_cast<FunctionDecl>(Val: S.CurContext)) {
13620	FD->setWillHaveBody(false);
13621	S.CheckImmediateEscalatingFunctionDefinition(FD, FSI: S.getCurFunction());
13622	}
13623	S.PopExpressionEvaluationContext();
13624	S.PopFunctionScopeInfo();
13625	}
13626
13627	SynthesizedFunctionScope(const SynthesizedFunctionScope &) = delete;
13628	SynthesizedFunctionScope &
13629	operator=(const SynthesizedFunctionScope &) = delete;
13630	};
13631
13632	/// List of active code synthesis contexts.
13633	///
13634	/// This vector is treated as a stack. As synthesis of one entity requires
13635	/// synthesis of another, additional contexts are pushed onto the stack.
13636	SmallVector<CodeSynthesisContext, `16`> CodeSynthesisContexts;
13637
13638	/// Specializations whose definitions are currently being instantiated.
13639	llvm::DenseSet<InstantiatingSpecializationsKey> InstantiatingSpecializations;
13640
13641	/// Non-dependent types used in templates that have already been instantiated
13642	/// by some template instantiation.
13643	llvm::DenseSet<QualType> InstantiatedNonDependentTypes;
13644
13645	/// Extra modules inspected when performing a lookup during a template
13646	/// instantiation. Computed lazily.
13647	SmallVector<Module *, `16`> CodeSynthesisContextLookupModules;
13648
13649	/// Cache of additional modules that should be used for name lookup
13650	/// within the current template instantiation. Computed lazily; use
13651	/// getLookupModules() to get a complete set.
13652	llvm::DenseSet<Module *> LookupModulesCache;
13653
13654	/// Map from the most recent declaration of a namespace to the most
13655	/// recent visible declaration of that namespace.
13656	llvm::DenseMap<NamedDecl , NamedDecl > VisibleNamespaceCache;
13657
13658	SFINAETrap CurrentSFINAEContext = nullptr*;
13659
13660	/// The number of \p CodeSynthesisContexts that are not template
13661	/// instantiations and, therefore, should not be counted as part of the
13662	/// instantiation depth.
13663	///
13664	/// When the instantiation depth reaches the user-configurable limit
13665	/// \p LangOptions::InstantiationDepth we will abort instantiation.
13666	// FIXME: Should we have a similar limit for other forms of synthesis?
13667	unsigned NonInstantiationEntries;
13668
13669	/// The depth of the context stack at the point when the most recent
13670	/// error or warning was produced.
13671	///
13672	/// This value is used to suppress printing of redundant context stacks
13673	/// when there are multiple errors or warnings in the same instantiation.
13674	// FIXME: Does this belong in Sema? It's tough to implement it anywhere else.
13675	unsigned LastEmittedCodeSynthesisContextDepth = `0`;
13676
13677	/// The template instantiation callbacks to trace or track
13678	/// instantiations (objects can be chained).
13679	///
13680	/// This callbacks is used to print, trace or track template
13681	/// instantiations as they are being constructed.
13682	std::vector<std::unique_ptr<TemplateInstantiationCallback>>
13683	TemplateInstCallbacks;
13684
13685	/// The current index into pack expansion arguments that will be
13686	/// used for substitution of parameter packs.
13687	///
13688	/// The pack expansion index will be none to indicate that parameter packs
13689	/// should be instantiated as themselves. Otherwise, the index specifies
13690	/// which argument within the parameter pack will be used for substitution.
13691	UnsignedOrNone ArgPackSubstIndex;
13692
13693	/// RAII object used to change the argument pack substitution index
13694	/// within a \c Sema object.
13695	///
13696	/// See \c ArgPackSubstIndex for more information.
13697	class ArgPackSubstIndexRAII {
13698	Sema &Self;
13699	UnsignedOrNone OldSubstIndex;
13700
13701	public:
13702	ArgPackSubstIndexRAII(Sema &Self, UnsignedOrNone NewSubstIndex)
13703	: Self(Self),
13704	OldSubstIndex(std::exchange(obj&: Self.ArgPackSubstIndex, new_val&: NewSubstIndex)) {}
13705
13706	~ArgPackSubstIndexRAII() { Self.ArgPackSubstIndex = OldSubstIndex; }
13707	ArgPackSubstIndexRAII(const ArgPackSubstIndexRAII &) = delete;
13708	ArgPackSubstIndexRAII &operator=(const ArgPackSubstIndexRAII &) = delete;
13709	};
13710
13711	bool pushCodeSynthesisContext(CodeSynthesisContext Ctx);
13712	void popCodeSynthesisContext();
13713
13714	void PrintContextStack(InstantiationContextDiagFuncRef DiagFunc) {
13715	if (!CodeSynthesisContexts.empty() &&
13716	CodeSynthesisContexts.size() != LastEmittedCodeSynthesisContextDepth) {
13717	PrintInstantiationStack(DiagFunc);
13718	LastEmittedCodeSynthesisContextDepth = CodeSynthesisContexts.size();
13719	}
13720	if (PragmaAttributeCurrentTargetDecl)
13721	PrintPragmaAttributeInstantiationPoint(DiagFunc);
13722	}
13723	void PrintContextStack() { PrintContextStack(DiagFunc: getDefaultDiagFunc()); }
13724	/// Prints the current instantiation stack through a series of
13725	/// notes.
13726	void PrintInstantiationStack(InstantiationContextDiagFuncRef DiagFunc);
13727	void PrintInstantiationStack() {
13728	PrintInstantiationStack(DiagFunc: getDefaultDiagFunc());
13729	}
13730
13731	/// Returns a pointer to the current SFINAE context, if any.
13732	[[nodiscard]] SFINAETrap getSFINAEContext() const* {
13733	return CurrentSFINAEContext;
13734	}
13735	[[nodiscard]] bool isSFINAEContext() const {
13736	return CurrentSFINAEContext != nullptr;
13737	}
13738
13739	/// Perform substitution on the type T with a given set of template
13740	/// arguments.
13741	///
13742	/// This routine substitutes the given template arguments into the
13743	/// type T and produces the instantiated type.
13744	///
13745	/// \param T the type into which the template arguments will be
13746	/// substituted. If this type is not dependent, it will be returned
13747	/// immediately.
13748	///
13749	/// \param Args the template arguments that will be
13750	/// substituted for the top-level template parameters within T.
13751	///
13752	/// \param Loc the location in the source code where this substitution
13753	/// is being performed. It will typically be the location of the
13754	/// declarator (if we're instantiating the type of some declaration)
13755	/// or the location of the type in the source code (if, e.g., we're
13756	/// instantiating the type of a cast expression).
13757	///
13758	/// \param Entity the name of the entity associated with a declaration
13759	/// being instantiated (if any). May be empty to indicate that there
13760	/// is no such entity (if, e.g., this is a type that occurs as part of
13761	/// a cast expression) or that the entity has no name (e.g., an
13762	/// unnamed function parameter).
13763	///
13764	/// \param AllowDeducedTST Whether a DeducedTemplateSpecializationType is
13765	/// acceptable as the top level type of the result.
13766	///
13767	/// \param IsIncompleteSubstitution If provided, the pointee will be set
13768	/// whenever substitution would perform a replacement with a null or
13769	/// non-existent template argument.
13770	///
13771	/// \returns If the instantiation succeeds, the instantiated
13772	/// type. Otherwise, produces diagnostics and returns a NULL type.
13773	TypeSourceInfo SubstType(TypeSourceInfo T,
13774	const MultiLevelTemplateArgumentList &TemplateArgs,
13775	SourceLocation Loc, DeclarationName Entity,
13776	bool AllowDeducedTST = false);
13777
13778	QualType SubstType(QualType T,
13779	const MultiLevelTemplateArgumentList &TemplateArgs,
13780	SourceLocation Loc, DeclarationName Entity,
13781	bool IsIncompleteSubstitution = nullptr*);
13782
13783	TypeSourceInfo *SubstType(TypeLoc TL,
13784	const MultiLevelTemplateArgumentList &TemplateArgs,
13785	SourceLocation Loc, DeclarationName Entity);
13786
13787	/// A form of SubstType intended specifically for instantiating the
13788	/// type of a FunctionDecl. Its purpose is solely to force the
13789	/// instantiation of default-argument expressions and to avoid
13790	/// instantiating an exception-specification.
13791	TypeSourceInfo *SubstFunctionDeclType(
13792	TypeSourceInfo T, const* MultiLevelTemplateArgumentList &TemplateArgs,
13793	SourceLocation Loc, DeclarationName Entity, CXXRecordDecl *ThisContext,
13794	Qualifiers ThisTypeQuals, bool EvaluateConstraints = true);
13795	void SubstExceptionSpec(FunctionDecl New, const* FunctionProtoType *Proto,
13796	const MultiLevelTemplateArgumentList &Args);
13797	bool SubstExceptionSpec(SourceLocation Loc,
13798	FunctionProtoType::ExceptionSpecInfo &ESI,
13799	SmallVectorImpl<QualType> &ExceptionStorage,
13800	const MultiLevelTemplateArgumentList &Args);
13801	ParmVarDecl *
13802	SubstParmVarDecl(ParmVarDecl *D,
13803	const MultiLevelTemplateArgumentList &TemplateArgs,
13804	int indexAdjustment, UnsignedOrNone NumExpansions,
13805	bool ExpectParameterPack, bool EvaluateConstraints = true);
13806
13807	/// Substitute the given template arguments into the given set of
13808	/// parameters, producing the set of parameter types that would be generated
13809	/// from such a substitution.
13810	bool SubstParmTypes(SourceLocation Loc, ArrayRef<ParmVarDecl *> Params,
13811	const FunctionProtoType::ExtParameterInfo *ExtParamInfos,
13812	const MultiLevelTemplateArgumentList &TemplateArgs,
13813	SmallVectorImpl<QualType> &ParamTypes,
13814	SmallVectorImpl<ParmVarDecl > OutParams,
13815	ExtParameterInfoBuilder &ParamInfos);
13816
13817	/// Substitute the given template arguments into the default argument.
13818	bool SubstDefaultArgument(SourceLocation Loc, ParmVarDecl *Param,
13819	const MultiLevelTemplateArgumentList &TemplateArgs,
13820	bool ForCallExpr = false);
13821	ExprResult SubstExpr(Expr *E,
13822	const MultiLevelTemplateArgumentList &TemplateArgs);
13823	/// Substitute an expression as if it is a address-of-operand, which makes it
13824	/// act like a CXXIdExpression rather than an attempt to call.
13825	ExprResult SubstCXXIdExpr(Expr *E,
13826	const MultiLevelTemplateArgumentList &TemplateArgs);
13827
13828	// A RAII type used by the TemplateDeclInstantiator and TemplateInstantiator
13829	// to disable constraint evaluation, then restore the state.
13830	template <typename InstTy> struct ConstraintEvalRAII {
13831	InstTy &TI;
13832	bool OldValue;
13833
13834	ConstraintEvalRAII(InstTy &TI)
13835	: TI(TI), OldValue(TI.getEvaluateConstraints()) {
13836	TI.setEvaluateConstraints(false);
13837	}
13838	~ConstraintEvalRAII() { TI.setEvaluateConstraints(OldValue); }
13839	ConstraintEvalRAII(const ConstraintEvalRAII &) = delete;
13840	ConstraintEvalRAII &operator=(const ConstraintEvalRAII &) = delete;
13841	};
13842
13843	// Must be used instead of SubstExpr at 'constraint checking' time.
13844	ExprResult
13845	SubstConstraintExpr(Expr *E,
13846	const MultiLevelTemplateArgumentList &TemplateArgs);
13847	// Unlike the above, this does not evaluate constraints.
13848	ExprResult SubstConstraintExprWithoutSatisfaction(
13849	Expr E, const* MultiLevelTemplateArgumentList &TemplateArgs);
13850
13851	/// Substitute the given template arguments into a list of
13852	/// expressions, expanding pack expansions if required.
13853	///
13854	/// \param Exprs The list of expressions to substitute into.
13855	///
13856	/// \param IsCall Whether this is some form of call, in which case
13857	/// default arguments will be dropped.
13858	///
13859	/// \param TemplateArgs The set of template arguments to substitute.
13860	///
13861	/// \param Outputs Will receive all of the substituted arguments.
13862	///
13863	/// \returns true if an error occurred, false otherwise.
13864	bool SubstExprs(ArrayRef<Expr > Exprs, bool* IsCall,
13865	const MultiLevelTemplateArgumentList &TemplateArgs,
13866	SmallVectorImpl<Expr *> &Outputs);
13867
13868	StmtResult SubstStmt(Stmt *S,
13869	const MultiLevelTemplateArgumentList &TemplateArgs);
13870
13871	ExprResult
13872	SubstInitializer(Expr E, const* MultiLevelTemplateArgumentList &TemplateArgs,
13873	bool CXXDirectInit);
13874
13875	/// Perform substitution on the base class specifiers of the
13876	/// given class template specialization.
13877	///
13878	/// Produces a diagnostic and returns true on error, returns false and
13879	/// attaches the instantiated base classes to the class template
13880	/// specialization if successful.
13881	bool SubstBaseSpecifiers(CXXRecordDecl Instantiation, CXXRecordDecl Pattern,
13882	const MultiLevelTemplateArgumentList &TemplateArgs);
13883
13884	/// Instantiate the definition of a class from a given pattern.
13885	///
13886	/// \param PointOfInstantiation The point of instantiation within the
13887	/// source code.
13888	///
13889	/// \param Instantiation is the declaration whose definition is being
13890	/// instantiated. This will be either a class template specialization
13891	/// or a member class of a class template specialization.
13892	///
13893	/// \param Pattern is the pattern from which the instantiation
13894	/// occurs. This will be either the declaration of a class template or
13895	/// the declaration of a member class of a class template.
13896	///
13897	/// \param TemplateArgs The template arguments to be substituted into
13898	/// the pattern.
13899	///
13900	/// \param TSK the kind of implicit or explicit instantiation to perform.
13901	///
13902	/// \param Complain whether to complain if the class cannot be instantiated
13903	/// due to the lack of a definition.
13904	///
13905	/// \returns true if an error occurred, false otherwise.
13906	bool InstantiateClass(SourceLocation PointOfInstantiation,
13907	CXXRecordDecl Instantiation, CXXRecordDecl Pattern,
13908	const MultiLevelTemplateArgumentList &TemplateArgs,
13909	TemplateSpecializationKind TSK, bool Complain = true);
13910
13911	private:
13912	bool InstantiateClassImpl(SourceLocation PointOfInstantiation,
13913	CXXRecordDecl *Instantiation,
13914	CXXRecordDecl *Pattern,
13915	const MultiLevelTemplateArgumentList &TemplateArgs,
13916	TemplateSpecializationKind TSK, bool Complain);
13917
13918	public:
13919	/// Instantiate the definition of an enum from a given pattern.
13920	///
13921	/// \param PointOfInstantiation The point of instantiation within the
13922	/// source code.
13923	/// \param Instantiation is the declaration whose definition is being
13924	/// instantiated. This will be a member enumeration of a class
13925	/// temploid specialization, or a local enumeration within a
13926	/// function temploid specialization.
13927	/// \param Pattern The templated declaration from which the instantiation
13928	/// occurs.
13929	/// \param TemplateArgs The template arguments to be substituted into
13930	/// the pattern.
13931	/// \param TSK The kind of implicit or explicit instantiation to perform.
13932	///
13933	/// \return \c true if an error occurred, \c false otherwise.
13934	bool InstantiateEnum(SourceLocation PointOfInstantiation,
13935	EnumDecl Instantiation, EnumDecl Pattern,
13936	const MultiLevelTemplateArgumentList &TemplateArgs,
13937	TemplateSpecializationKind TSK);
13938
13939	/// Instantiate the definition of a field from the given pattern.
13940	///
13941	/// \param PointOfInstantiation The point of instantiation within the
13942	/// source code.
13943	/// \param Instantiation is the declaration whose definition is being
13944	/// instantiated. This will be a class of a class temploid
13945	/// specialization, or a local enumeration within a function temploid
13946	/// specialization.
13947	/// \param Pattern The templated declaration from which the instantiation
13948	/// occurs.
13949	/// \param TemplateArgs The template arguments to be substituted into
13950	/// the pattern.
13951	///
13952	/// \return \c true if an error occurred, \c false otherwise.
13953	bool InstantiateInClassInitializer(
13954	SourceLocation PointOfInstantiation, FieldDecl *Instantiation,
13955	FieldDecl Pattern, const* MultiLevelTemplateArgumentList &TemplateArgs);
13956
13957	bool usesPartialOrExplicitSpecialization(
13958	SourceLocation Loc, ClassTemplateSpecializationDecl *ClassTemplateSpec);
13959
13960	bool InstantiateClassTemplateSpecialization(
13961	SourceLocation PointOfInstantiation,
13962	ClassTemplateSpecializationDecl *ClassTemplateSpec,
13963	TemplateSpecializationKind TSK, bool Complain,
13964	bool PrimaryStrictPackMatch);
13965
13966	/// Instantiates the definitions of all of the member
13967	/// of the given class, which is an instantiation of a class template
13968	/// or a member class of a template.
13969	void
13970	InstantiateClassMembers(SourceLocation PointOfInstantiation,
13971	CXXRecordDecl *Instantiation,
13972	const MultiLevelTemplateArgumentList &TemplateArgs,
13973	TemplateSpecializationKind TSK);
13974
13975	/// Instantiate the definitions of all of the members of the
13976	/// given class template specialization, which was named as part of an
13977	/// explicit instantiation.
13978	void InstantiateClassTemplateSpecializationMembers(
13979	SourceLocation PointOfInstantiation,
13980	ClassTemplateSpecializationDecl *ClassTemplateSpec,
13981	TemplateSpecializationKind TSK);
13982
13983	NestedNameSpecifierLoc SubstNestedNameSpecifierLoc(
13984	NestedNameSpecifierLoc NNS,
13985	const MultiLevelTemplateArgumentList &TemplateArgs);
13986
13987	/// Do template substitution on declaration name info.
13988	DeclarationNameInfo
13989	SubstDeclarationNameInfo(const DeclarationNameInfo &NameInfo,
13990	const MultiLevelTemplateArgumentList &TemplateArgs);
13991	TemplateName
13992	SubstTemplateName(SourceLocation TemplateKWLoc,
13993	NestedNameSpecifierLoc &QualifierLoc, TemplateName Name,
13994	SourceLocation NameLoc,
13995	const MultiLevelTemplateArgumentList &TemplateArgs);
13996
13997	bool SubstTypeConstraint(TemplateTypeParmDecl Inst, const* TypeConstraint *TC,
13998	const MultiLevelTemplateArgumentList &TemplateArgs,
13999	bool EvaluateConstraint);
14000
14001	/// Determine whether we are currently performing template instantiation.
14002	bool inTemplateInstantiation() const {
14003	return CodeSynthesisContexts.size() > NonInstantiationEntries;
14004	}
14005
14006	/// Determine whether we are currently performing constraint substitution.
14007	bool inConstraintSubstitution() const {
14008	return !CodeSynthesisContexts.empty() &&
14009	CodeSynthesisContexts.back().InConstraintSubstitution;
14010	}
14011
14012	bool inParameterMappingSubstitution() const {
14013	return !CodeSynthesisContexts.empty() &&
14014	CodeSynthesisContexts.back().InParameterMappingSubstitution &&
14015	!inConstraintSubstitution();
14016	}
14017
14018	using EntityPrinter = llvm::function_ref<void(llvm::raw_ostream &)>;
14019
14020	/// \brief create a Requirement::SubstitutionDiagnostic with only a
14021	/// SubstitutedEntity and DiagLoc using ASTContext's allocator.
14022	concepts::Requirement::SubstitutionDiagnostic *
14023	createSubstDiagAt(SourceLocation Location, EntityPrinter Printer);
14024
14025	///@}
14026
14027	//
14028	//
14029	// -------------------------------------------------------------------------
14030	//
14031	//
14032
14033	/// \name C++ Template Declaration Instantiation
14034	/// Implementations are in SemaTemplateInstantiateDecl.cpp
14035	///@{
14036
14037	public:
14038	/// An entity for which implicit template instantiation is required.
14039	///
14040	/// The source location associated with the declaration is the first place in
14041	/// the source code where the declaration was "used". It is not necessarily
14042	/// the point of instantiation (which will be either before or after the
14043	/// namespace-scope declaration that triggered this implicit instantiation),
14044	/// However, it is the location that diagnostics should generally refer to,
14045	/// because users will need to know what code triggered the instantiation.
14046	typedef std::pair<ValueDecl *, SourceLocation> PendingImplicitInstantiation;
14047
14048	/// The queue of implicit template instantiations that are required
14049	/// but have not yet been performed.
14050	std::deque<PendingImplicitInstantiation> PendingInstantiations;
14051
14052	/// Queue of implicit template instantiations that cannot be performed
14053	/// eagerly.
14054	SmallVector<PendingImplicitInstantiation, `1`> LateParsedInstantiations;
14055
14056	SmallVector<SmallVector<VTableUse, `16`>, `8`> SavedVTableUses;
14057	SmallVector<std::deque<PendingImplicitInstantiation>, `8`>
14058	SavedPendingInstantiations;
14059
14060	/// The queue of implicit template instantiations that are required
14061	/// and must be performed within the current local scope.
14062	///
14063	/// This queue is only used for member functions of local classes in
14064	/// templates, which must be instantiated in the same scope as their
14065	/// enclosing function, so that they can reference function-local
14066	/// types, static variables, enumerators, etc.
14067	std::deque<PendingImplicitInstantiation> PendingLocalImplicitInstantiations;
14068
14069	class LocalEagerInstantiationScope {
14070	public:
14071	LocalEagerInstantiationScope(Sema &S, bool AtEndOfTU)
14072	: S(S), AtEndOfTU(AtEndOfTU) {
14073	SavedPendingLocalImplicitInstantiations.swap(
14074	x&: S.PendingLocalImplicitInstantiations);
14075	}
14076
14077	void perform() {
14078	S.PerformPendingInstantiations(/LocalOnly=/LocalOnly: true,
14079	/AtEndOfTU=/AtEndOfTU);
14080	}
14081
14082	~LocalEagerInstantiationScope() {
14083	assert(S.PendingLocalImplicitInstantiations.empty() &&
14084	"there shouldn't be any pending local implicit instantiations");
14085	SavedPendingLocalImplicitInstantiations.swap(
14086	x&: S.PendingLocalImplicitInstantiations);
14087	}
14088
14089	LocalEagerInstantiationScope(const LocalEagerInstantiationScope &) = delete;
14090	LocalEagerInstantiationScope &
14091	operator=(const LocalEagerInstantiationScope &) = delete;
14092
14093	private:
14094	Sema &S;
14095	bool AtEndOfTU;
14096	std::deque<PendingImplicitInstantiation>
14097	SavedPendingLocalImplicitInstantiations;
14098	};
14099
14100	/// Records and restores the CurFPFeatures state on entry/exit of compound
14101	/// statements.
14102	class FPFeaturesStateRAII {
14103	public:
14104	FPFeaturesStateRAII(Sema &S);
14105	~FPFeaturesStateRAII();
14106	FPOptionsOverride getOverrides() { return OldOverrides; }
14107
14108	private:
14109	Sema &S;
14110	FPOptions OldFPFeaturesState;
14111	FPOptionsOverride OldOverrides;
14112	LangOptions::FPEvalMethodKind OldEvalMethod;
14113	SourceLocation OldFPPragmaLocation;
14114	};
14115
14116	class GlobalEagerInstantiationScope {
14117	public:
14118	GlobalEagerInstantiationScope(Sema &S, bool Enabled, bool AtEndOfTU)
14119	: S(S), Enabled(Enabled), AtEndOfTU(AtEndOfTU) {
14120	if (!Enabled)
14121	return;
14122
14123	S.SavedPendingInstantiations.emplace_back();
14124	S.SavedPendingInstantiations.back().swap(x&: S.PendingInstantiations);
14125
14126	S.SavedVTableUses.emplace_back();
14127	S.SavedVTableUses.back().swap(RHS&: S.VTableUses);
14128	}
14129
14130	void perform() {
14131	if (Enabled) {
14132	S.DefineUsedVTables();
14133	S.PerformPendingInstantiations(/LocalOnly=/LocalOnly: false,
14134	/AtEndOfTU=/AtEndOfTU);
14135	}
14136	}
14137
14138	~GlobalEagerInstantiationScope() {
14139	if (!Enabled)
14140	return;
14141
14142	// Restore the set of pending vtables.
14143	assert(S.VTableUses.empty() &&
14144	"VTableUses should be empty before it is discarded.");
14145	S.VTableUses.swap(RHS&: S.SavedVTableUses.back());
14146	S.SavedVTableUses.pop_back();
14147
14148	// Restore the set of pending implicit instantiations.
14149	if ((S.TUKind != TU_Prefix \|\| !S.LangOpts.PCHInstantiateTemplates) &&
14150	AtEndOfTU) {
14151	assert(S.PendingInstantiations.empty() &&
14152	"PendingInstantiations should be empty before it is discarded.");
14153	S.PendingInstantiations.swap(x&: S.SavedPendingInstantiations.back());
14154	S.SavedPendingInstantiations.pop_back();
14155	} else {
14156	// Template instantiations in the PCH may be delayed until the TU.
14157	S.PendingInstantiations.swap(x&: S.SavedPendingInstantiations.back());
14158	S.PendingInstantiations.insert(
14159	position: S.PendingInstantiations.end(),
14160	first: S.SavedPendingInstantiations.back().begin(),
14161	last: S.SavedPendingInstantiations.back().end());
14162	S.SavedPendingInstantiations.pop_back();
14163	}
14164	}
14165
14166	GlobalEagerInstantiationScope(const GlobalEagerInstantiationScope &) =
14167	delete;
14168	GlobalEagerInstantiationScope &
14169	operator=(const GlobalEagerInstantiationScope &) = delete;
14170
14171	private:
14172	Sema &S;
14173	bool Enabled;
14174	bool AtEndOfTU;
14175	};
14176
14177	ExplicitSpecifier instantiateExplicitSpecifier(
14178	const MultiLevelTemplateArgumentList &TemplateArgs, ExplicitSpecifier ES);
14179
14180	struct LateInstantiatedAttribute {
14181	const Attr *TmplAttr;
14182	LocalInstantiationScope *Scope;
14183	Decl *NewDecl;
14184
14185	LateInstantiatedAttribute(const Attr A, LocalInstantiationScope S,
14186	Decl *D)
14187	: TmplAttr(A), Scope(S), NewDecl(D) {}
14188	};
14189	typedef SmallVector<LateInstantiatedAttribute, `1`> LateInstantiatedAttrVec;
14190
14191	void InstantiateAttrs(const MultiLevelTemplateArgumentList &TemplateArgs,
14192	const Decl Pattern, Decl Inst,
14193	LateInstantiatedAttrVec LateAttrs = nullptr*,
14194	LocalInstantiationScope OuterMostScope = nullptr*);
14195
14196	/// Update instantiation attributes after template was late parsed.
14197	///
14198	/// Some attributes are evaluated based on the body of template. If it is
14199	/// late parsed, such attributes cannot be evaluated when declaration is
14200	/// instantiated. This function is used to update instantiation attributes
14201	/// when template definition is ready.
14202	void updateAttrsForLateParsedTemplate(const Decl Pattern, Decl Inst);
14203
14204	void
14205	InstantiateAttrsForDecl(const MultiLevelTemplateArgumentList &TemplateArgs,
14206	const Decl Pattern, Decl Inst,
14207	LateInstantiatedAttrVec LateAttrs = nullptr*,
14208	LocalInstantiationScope OuterMostScope = nullptr*);
14209
14210	/// In the MS ABI, we need to instantiate default arguments of dllexported
14211	/// default constructors along with the constructor definition. This allows IR
14212	/// gen to emit a constructor closure which calls the default constructor with
14213	/// its default arguments.
14214	void InstantiateDefaultCtorDefaultArgs(CXXConstructorDecl *Ctor);
14215
14216	bool InstantiateDefaultArgument(SourceLocation CallLoc, FunctionDecl *FD,
14217	ParmVarDecl *Param);
14218	void InstantiateExceptionSpec(SourceLocation PointOfInstantiation,
14219	FunctionDecl *Function);
14220
14221	/// Instantiate (or find existing instantiation of) a function template with a
14222	/// given set of template arguments.
14223	///
14224	/// Usually this should not be used, and template argument deduction should be
14225	/// used in its place.
14226	FunctionDecl *InstantiateFunctionDeclaration(
14227	FunctionTemplateDecl FTD, const* TemplateArgumentList *Args,
14228	SourceLocation Loc,
14229	CodeSynthesisContext::SynthesisKind CSC =
14230	CodeSynthesisContext::ExplicitTemplateArgumentSubstitution);
14231
14232	/// Instantiate the definition of the given function from its
14233	/// template.
14234	///
14235	/// \param PointOfInstantiation the point at which the instantiation was
14236	/// required. Note that this is not precisely a "point of instantiation"
14237	/// for the function, but it's close.
14238	///
14239	/// \param Function the already-instantiated declaration of a
14240	/// function template specialization or member function of a class template
14241	/// specialization.
14242	///
14243	/// \param Recursive if true, recursively instantiates any functions that
14244	/// are required by this instantiation.
14245	///
14246	/// \param DefinitionRequired if true, then we are performing an explicit
14247	/// instantiation where the body of the function is required. Complain if
14248	/// there is no such body.
14249	void InstantiateFunctionDefinition(SourceLocation PointOfInstantiation,
14250	FunctionDecl *Function,
14251	bool Recursive = false,
14252	bool DefinitionRequired = false,
14253	bool AtEndOfTU = false);
14254	VarTemplateSpecializationDecl *BuildVarTemplateInstantiation(
14255	VarTemplateDecl VarTemplate, VarDecl FromVar,
14256	const TemplateArgumentList *PartialSpecArgs,
14257	SmallVectorImpl<TemplateArgument> &Converted,
14258	SourceLocation PointOfInstantiation,
14259	LateInstantiatedAttrVec LateAttrs = nullptr*,
14260	LocalInstantiationScope StartingScope = nullptr*);
14261
14262	/// Instantiates a variable template specialization by completing it
14263	/// with appropriate type information and initializer.
14264	VarTemplateSpecializationDecl *CompleteVarTemplateSpecializationDecl(
14265	VarTemplateSpecializationDecl VarSpec, VarDecl PatternDecl,
14266	const MultiLevelTemplateArgumentList &TemplateArgs);
14267
14268	/// BuildVariableInstantiation - Used after a new variable has been created.
14269	/// Sets basic variable data and decides whether to postpone the
14270	/// variable instantiation.
14271	void
14272	BuildVariableInstantiation(VarDecl NewVar, VarDecl OldVar,
14273	const MultiLevelTemplateArgumentList &TemplateArgs,
14274	LateInstantiatedAttrVec *LateAttrs,
14275	DeclContext *Owner,
14276	LocalInstantiationScope *StartingScope,
14277	bool InstantiatingVarTemplate = false,
14278	VarTemplateSpecializationDecl PrevVTSD = nullptr*);
14279
14280	/// Instantiate the initializer of a variable.
14281	void InstantiateVariableInitializer(
14282	VarDecl Var, VarDecl OldVar,
14283	const MultiLevelTemplateArgumentList &TemplateArgs);
14284
14285	/// Instantiate the definition of the given variable from its
14286	/// template.
14287	///
14288	/// \param PointOfInstantiation the point at which the instantiation was
14289	/// required. Note that this is not precisely a "point of instantiation"
14290	/// for the variable, but it's close.
14291	///
14292	/// \param Var the already-instantiated declaration of a templated variable.
14293	///
14294	/// \param Recursive if true, recursively instantiates any functions that
14295	/// are required by this instantiation.
14296	///
14297	/// \param DefinitionRequired if true, then we are performing an explicit
14298	/// instantiation where a definition of the variable is required. Complain
14299	/// if there is no such definition.
14300	void InstantiateVariableDefinition(SourceLocation PointOfInstantiation,
14301	VarDecl Var, bool* Recursive = false,
14302	bool DefinitionRequired = false,
14303	bool AtEndOfTU = false);
14304
14305	void InstantiateMemInitializers(
14306	CXXConstructorDecl New, const* CXXConstructorDecl *Tmpl,
14307	const MultiLevelTemplateArgumentList &TemplateArgs);
14308
14309	/// Find the instantiation of the given declaration within the
14310	/// current instantiation.
14311	///
14312	/// This routine is intended to be used when \p D is a declaration
14313	/// referenced from within a template, that needs to mapped into the
14314	/// corresponding declaration within an instantiation. For example,
14315	/// given:
14316	///
14317	/// \code
14318	/// template<typename T>
14319	/// struct X {
14320	/// enum Kind {
14321	/// KnownValue = sizeof(T)
14322	/// };
14323	///
14324	/// bool getKind() const { return KnownValue; }
14325	/// };
14326	///
14327	/// template struct X<int>;
14328	/// \endcode
14329	///
14330	/// In the instantiation of X<int>::getKind(), we need to map the \p
14331	/// EnumConstantDecl for \p KnownValue (which refers to
14332	/// X<T>::<Kind>::KnownValue) to its instantiation
14333	/// (X<int>::<Kind>::KnownValue).
14334	/// \p FindInstantiatedDecl performs this mapping from within the
14335	/// instantiation of X<int>.
14336	NamedDecl *
14337	FindInstantiatedDecl(SourceLocation Loc, NamedDecl *D,
14338	const MultiLevelTemplateArgumentList &TemplateArgs,
14339	bool FindingInstantiatedContext = false);
14340
14341	/// Finds the instantiation of the given declaration context
14342	/// within the current instantiation.
14343	///
14344	/// \returns NULL if there was an error
14345	DeclContext *
14346	FindInstantiatedContext(SourceLocation Loc, DeclContext *DC,
14347	const MultiLevelTemplateArgumentList &TemplateArgs);
14348
14349	Decl SubstDecl(Decl D, DeclContext *Owner,
14350	const MultiLevelTemplateArgumentList &TemplateArgs);
14351
14352	/// Substitute the name and return type of a defaulted 'operator<=>' to form
14353	/// an implicit 'operator=='.
14354	FunctionDecl SubstSpaceshipAsEqualEqual(CXXRecordDecl RD,
14355	FunctionDecl *Spaceship);
14356
14357	/// Performs template instantiation for all implicit template
14358	/// instantiations we have seen until this point.
14359	void PerformPendingInstantiations(bool LocalOnly = false,
14360	bool AtEndOfTU = true);
14361
14362	TemplateParameterList *
14363	SubstTemplateParams(TemplateParameterList Params, DeclContext Owner,
14364	const MultiLevelTemplateArgumentList &TemplateArgs,
14365	bool EvaluateConstraints = true);
14366
14367	void PerformDependentDiagnostics(
14368	const DeclContext *Pattern,
14369	const MultiLevelTemplateArgumentList &TemplateArgs);
14370
14371	private:
14372	/// Introduce the instantiated local variables into the local
14373	/// instantiation scope.
14374	void addInstantiatedLocalVarsToScope(FunctionDecl *Function,
14375	const FunctionDecl *PatternDecl,
14376	LocalInstantiationScope &Scope);
14377	/// Introduce the instantiated function parameters into the local
14378	/// instantiation scope, and set the parameter names to those used
14379	/// in the template.
14380	bool addInstantiatedParametersToScope(
14381	FunctionDecl Function, const* FunctionDecl *PatternDecl,
14382	LocalInstantiationScope &Scope,
14383	const MultiLevelTemplateArgumentList &TemplateArgs);
14384
14385	/// Introduce the instantiated captures of the lambda into the local
14386	/// instantiation scope.
14387	bool addInstantiatedCapturesToScope(
14388	FunctionDecl Function, const* FunctionDecl *PatternDecl,
14389	LocalInstantiationScope &Scope,
14390	const MultiLevelTemplateArgumentList &TemplateArgs);
14391
14392	int ParsingClassDepth = `0`;
14393
14394	class SavePendingParsedClassStateRAII {
14395	public:
14396	SavePendingParsedClassStateRAII(Sema &S) : S(S) { swapSavedState(); }
14397
14398	~SavePendingParsedClassStateRAII() {
14399	assert(S.DelayedOverridingExceptionSpecChecks.empty() &&
14400	"there shouldn't be any pending delayed exception spec checks");
14401	assert(S.DelayedEquivalentExceptionSpecChecks.empty() &&
14402	"there shouldn't be any pending delayed exception spec checks");
14403	swapSavedState();
14404	}
14405
14406	SavePendingParsedClassStateRAII(const SavePendingParsedClassStateRAII &) =
14407	delete;
14408	SavePendingParsedClassStateRAII &
14409	operator=(const SavePendingParsedClassStateRAII &) = delete;
14410
14411	private:
14412	Sema &S;
14413	decltype(DelayedOverridingExceptionSpecChecks)
14414	SavedOverridingExceptionSpecChecks;
14415	decltype(DelayedEquivalentExceptionSpecChecks)
14416	SavedEquivalentExceptionSpecChecks;
14417
14418	void swapSavedState() {
14419	SavedOverridingExceptionSpecChecks.swap(
14420	RHS&: S.DelayedOverridingExceptionSpecChecks);
14421	SavedEquivalentExceptionSpecChecks.swap(
14422	RHS&: S.DelayedEquivalentExceptionSpecChecks);
14423	}
14424	};
14425
14426	///@}
14427
14428	//
14429	//
14430	// -------------------------------------------------------------------------
14431	//
14432	//
14433
14434	/// \name C++ Variadic Templates
14435	/// Implementations are in SemaTemplateVariadic.cpp
14436	///@{
14437
14438	public:
14439	/// Determine whether an unexpanded parameter pack might be permitted in this
14440	/// location. Useful for error recovery.
14441	bool isUnexpandedParameterPackPermitted();
14442
14443	/// The context in which an unexpanded parameter pack is
14444	/// being diagnosed.
14445	///
14446	/// Note that the values of this enumeration line up with the first
14447	/// argument to the \c err_unexpanded_parameter_pack diagnostic.
14448	enum UnexpandedParameterPackContext {
14449	/// An arbitrary expression.
14450	UPPC_Expression = `0`,
14451
14452	/// The base type of a class type.
14453	UPPC_BaseType,
14454
14455	/// The type of an arbitrary declaration.
14456	UPPC_DeclarationType,
14457
14458	/// The type of a data member.
14459	UPPC_DataMemberType,
14460
14461	/// The size of a bit-field.
14462	UPPC_BitFieldWidth,
14463
14464	/// The expression in a static assertion.
14465	UPPC_StaticAssertExpression,
14466
14467	/// The fixed underlying type of an enumeration.
14468	UPPC_FixedUnderlyingType,
14469
14470	/// The enumerator value.
14471	UPPC_EnumeratorValue,
14472
14473	/// A using declaration.
14474	UPPC_UsingDeclaration,
14475
14476	/// A friend declaration.
14477	UPPC_FriendDeclaration,
14478
14479	/// A declaration qualifier.
14480	UPPC_DeclarationQualifier,
14481
14482	/// An initializer.
14483	UPPC_Initializer,
14484
14485	/// A default argument.
14486	UPPC_DefaultArgument,
14487
14488	/// The type of a non-type template parameter.
14489	UPPC_NonTypeTemplateParameterType,
14490
14491	/// The type of an exception.
14492	UPPC_ExceptionType,
14493
14494	/// Explicit specialization.
14495	UPPC_ExplicitSpecialization,
14496
14497	/// Partial specialization.
14498	UPPC_PartialSpecialization,
14499
14500	/// Microsoft __if_exists.
14501	UPPC_IfExists,
14502
14503	/// Microsoft __if_not_exists.
14504	UPPC_IfNotExists,
14505
14506	/// Lambda expression.
14507	UPPC_Lambda,
14508
14509	/// Block expression.
14510	UPPC_Block,
14511
14512	/// A type constraint.
14513	UPPC_TypeConstraint,
14514
14515	// A requirement in a requires-expression.
14516	UPPC_Requirement,
14517
14518	// A requires-clause.
14519	UPPC_RequiresClause,
14520	};
14521
14522	/// Diagnose unexpanded parameter packs.
14523	///
14524	/// \param Loc The location at which we should emit the diagnostic.
14525	///
14526	/// \param UPPC The context in which we are diagnosing unexpanded
14527	/// parameter packs.
14528	///
14529	/// \param Unexpanded the set of unexpanded parameter packs.
14530	///
14531	/// \returns true if an error occurred, false otherwise.
14532	bool DiagnoseUnexpandedParameterPacks(
14533	SourceLocation Loc, UnexpandedParameterPackContext UPPC,
14534	ArrayRef<UnexpandedParameterPack> Unexpanded);
14535
14536	/// If the given type contains an unexpanded parameter pack,
14537	/// diagnose the error.
14538	///
14539	/// \param Loc The source location where a diagnostc should be emitted.
14540	///
14541	/// \param T The type that is being checked for unexpanded parameter
14542	/// packs.
14543	///
14544	/// \returns true if an error occurred, false otherwise.
14545	bool DiagnoseUnexpandedParameterPack(SourceLocation Loc, TypeSourceInfo *T,
14546	UnexpandedParameterPackContext UPPC);
14547
14548	/// If the given expression contains an unexpanded parameter
14549	/// pack, diagnose the error.
14550	///
14551	/// \param E The expression that is being checked for unexpanded
14552	/// parameter packs.
14553	///
14554	/// \returns true if an error occurred, false otherwise.
14555	bool DiagnoseUnexpandedParameterPack(
14556	Expr *E, UnexpandedParameterPackContext UPPC = UPPC_Expression);
14557
14558	/// If the given requirees-expression contains an unexpanded reference to one
14559	/// of its own parameter packs, diagnose the error.
14560	///
14561	/// \param RE The requiress-expression that is being checked for unexpanded
14562	/// parameter packs.
14563	///
14564	/// \returns true if an error occurred, false otherwise.
14565	bool DiagnoseUnexpandedParameterPackInRequiresExpr(RequiresExpr *RE);
14566
14567	/// If the given nested-name-specifier contains an unexpanded
14568	/// parameter pack, diagnose the error.
14569	///
14570	/// \param SS The nested-name-specifier that is being checked for
14571	/// unexpanded parameter packs.
14572	///
14573	/// \returns true if an error occurred, false otherwise.
14574	bool DiagnoseUnexpandedParameterPack(const CXXScopeSpec &SS,
14575	UnexpandedParameterPackContext UPPC);
14576
14577	/// If the given name contains an unexpanded parameter pack,
14578	/// diagnose the error.
14579	///
14580	/// \param NameInfo The name (with source location information) that
14581	/// is being checked for unexpanded parameter packs.
14582	///
14583	/// \returns true if an error occurred, false otherwise.
14584	bool DiagnoseUnexpandedParameterPack(const DeclarationNameInfo &NameInfo,
14585	UnexpandedParameterPackContext UPPC);
14586
14587	/// If the given template name contains an unexpanded parameter pack,
14588	/// diagnose the error.
14589	///
14590	/// \param Loc The location of the template name.
14591	///
14592	/// \param Template The template name that is being checked for unexpanded
14593	/// parameter packs.
14594	///
14595	/// \returns true if an error occurred, false otherwise.
14596	bool DiagnoseUnexpandedParameterPack(SourceLocation Loc,
14597	TemplateName Template,
14598	UnexpandedParameterPackContext UPPC);
14599
14600	/// If the given template argument contains an unexpanded parameter
14601	/// pack, diagnose the error.
14602	///
14603	/// \param Arg The template argument that is being checked for unexpanded
14604	/// parameter packs.
14605	///
14606	/// \returns true if an error occurred, false otherwise.
14607	bool DiagnoseUnexpandedParameterPack(TemplateArgumentLoc Arg,
14608	UnexpandedParameterPackContext UPPC);
14609
14610	/// Collect the set of unexpanded parameter packs within the given
14611	/// template argument.
14612	///
14613	/// \param Arg The template argument that will be traversed to find
14614	/// unexpanded parameter packs.
14615	void collectUnexpandedParameterPacks(
14616	TemplateArgument Arg,
14617	SmallVectorImpl<UnexpandedParameterPack> &Unexpanded);
14618
14619	/// Collect the set of unexpanded parameter packs within the given
14620	/// template argument.
14621	///
14622	/// \param Arg The template argument that will be traversed to find
14623	/// unexpanded parameter packs.
14624	void collectUnexpandedParameterPacks(
14625	TemplateArgumentLoc Arg,
14626	SmallVectorImpl<UnexpandedParameterPack> &Unexpanded);
14627
14628	/// Collect the set of unexpanded parameter packs within the given
14629	/// type.
14630	///
14631	/// \param T The type that will be traversed to find
14632	/// unexpanded parameter packs.
14633	void collectUnexpandedParameterPacks(
14634	QualType T, SmallVectorImpl<UnexpandedParameterPack> &Unexpanded);
14635
14636	/// Collect the set of unexpanded parameter packs within the given
14637	/// type.
14638	///
14639	/// \param TL The type that will be traversed to find
14640	/// unexpanded parameter packs.
14641	void collectUnexpandedParameterPacks(
14642	TypeLoc TL, SmallVectorImpl<UnexpandedParameterPack> &Unexpanded);
14643
14644	/// Collect the set of unexpanded parameter packs within the given
14645	/// nested-name-specifier.
14646	///
14647	/// \param NNS The nested-name-specifier that will be traversed to find
14648	/// unexpanded parameter packs.
14649	void collectUnexpandedParameterPacks(
14650	NestedNameSpecifierLoc NNS,
14651	SmallVectorImpl<UnexpandedParameterPack> &Unexpanded);
14652
14653	/// Collect the set of unexpanded parameter packs within the given
14654	/// name.
14655	///
14656	/// \param NameInfo The name that will be traversed to find
14657	/// unexpanded parameter packs.
14658	void collectUnexpandedParameterPacks(
14659	const DeclarationNameInfo &NameInfo,
14660	SmallVectorImpl<UnexpandedParameterPack> &Unexpanded);
14661
14662	/// Collect the set of unexpanded parameter packs within the given
14663	/// expression.
14664	static void collectUnexpandedParameterPacks(
14665	Expr *E, SmallVectorImpl<UnexpandedParameterPack> &Unexpanded);
14666
14667	/// Invoked when parsing a template argument.
14668	///
14669	/// \param Arg the template argument, which may already be invalid.
14670	///
14671	/// If it is followed by ellipsis, this function is called before
14672	/// `ActOnPackExpansion`.
14673	ParsedTemplateArgument
14674	ActOnTemplateTemplateArgument(const ParsedTemplateArgument &Arg);
14675
14676	/// Invoked when parsing a template argument followed by an
14677	/// ellipsis, which creates a pack expansion.
14678	///
14679	/// \param Arg The template argument preceding the ellipsis, which
14680	/// may already be invalid.
14681	///
14682	/// \param EllipsisLoc The location of the ellipsis.
14683	ParsedTemplateArgument ActOnPackExpansion(const ParsedTemplateArgument &Arg,
14684	SourceLocation EllipsisLoc);
14685
14686	/// Invoked when parsing a type followed by an ellipsis, which
14687	/// creates a pack expansion.
14688	///
14689	/// \param Type The type preceding the ellipsis, which will become
14690	/// the pattern of the pack expansion.
14691	///
14692	/// \param EllipsisLoc The location of the ellipsis.
14693	TypeResult ActOnPackExpansion(ParsedType Type, SourceLocation EllipsisLoc);
14694
14695	/// Construct a pack expansion type from the pattern of the pack
14696	/// expansion.
14697	TypeSourceInfo CheckPackExpansion(TypeSourceInfo Pattern,
14698	SourceLocation EllipsisLoc,
14699	UnsignedOrNone NumExpansions);
14700
14701	/// Construct a pack expansion type from the pattern of the pack
14702	/// expansion.
14703	QualType CheckPackExpansion(QualType Pattern, SourceRange PatternRange,
14704	SourceLocation EllipsisLoc,
14705	UnsignedOrNone NumExpansions);
14706
14707	/// Invoked when parsing an expression followed by an ellipsis, which
14708	/// creates a pack expansion.
14709	///
14710	/// \param Pattern The expression preceding the ellipsis, which will become
14711	/// the pattern of the pack expansion.
14712	///
14713	/// \param EllipsisLoc The location of the ellipsis.
14714	ExprResult ActOnPackExpansion(Expr *Pattern, SourceLocation EllipsisLoc);
14715
14716	/// Invoked when parsing an expression followed by an ellipsis, which
14717	/// creates a pack expansion.
14718	///
14719	/// \param Pattern The expression preceding the ellipsis, which will become
14720	/// the pattern of the pack expansion.
14721	///
14722	/// \param EllipsisLoc The location of the ellipsis.
14723	ExprResult CheckPackExpansion(Expr *Pattern, SourceLocation EllipsisLoc,
14724	UnsignedOrNone NumExpansions);
14725
14726	/// Determine whether we could expand a pack expansion with the
14727	/// given set of parameter packs into separate arguments by repeatedly
14728	/// transforming the pattern.
14729	///
14730	/// \param EllipsisLoc The location of the ellipsis that identifies the
14731	/// pack expansion.
14732	///
14733	/// \param PatternRange The source range that covers the entire pattern of
14734	/// the pack expansion.
14735	///
14736	/// \param Unexpanded The set of unexpanded parameter packs within the
14737	/// pattern.
14738	///
14739	/// \param ShouldExpand Will be set to \c true if the transformer should
14740	/// expand the corresponding pack expansions into separate arguments. When
14741	/// set, \c NumExpansions must also be set.
14742	///
14743	/// \param RetainExpansion Whether the caller should add an unexpanded
14744	/// pack expansion after all of the expanded arguments. This is used
14745	/// when extending explicitly-specified template argument packs per
14746	/// C++0x [temp.arg.explicit]p9.
14747	///
14748	/// \param NumExpansions The number of separate arguments that will be in
14749	/// the expanded form of the corresponding pack expansion. This is both an
14750	/// input and an output parameter, which can be set by the caller if the
14751	/// number of expansions is known a priori (e.g., due to a prior substitution)
14752	/// and will be set by the callee when the number of expansions is known.
14753	/// The callee must set this value when \c ShouldExpand is \c true; it may
14754	/// set this value in other cases.
14755	///
14756	/// \returns true if an error occurred (e.g., because the parameter packs
14757	/// are to be instantiated with arguments of different lengths), false
14758	/// otherwise. If false, \c ShouldExpand (and possibly \c NumExpansions)
14759	/// must be set.
14760	bool CheckParameterPacksForExpansion(
14761	SourceLocation EllipsisLoc, SourceRange PatternRange,
14762	ArrayRef<UnexpandedParameterPack> Unexpanded,
14763	const MultiLevelTemplateArgumentList &TemplateArgs,
14764	bool FailOnPackProducingTemplates, bool &ShouldExpand,
14765	bool &RetainExpansion, UnsignedOrNone &NumExpansions,
14766	bool Diagnose = true);
14767
14768	/// Determine the number of arguments in the given pack expansion
14769	/// type.
14770	///
14771	/// This routine assumes that the number of arguments in the expansion is
14772	/// consistent across all of the unexpanded parameter packs in its pattern.
14773	///
14774	/// Returns an empty Optional if the type can't be expanded.
14775	UnsignedOrNone getNumArgumentsInExpansion(
14776	QualType T, const MultiLevelTemplateArgumentList &TemplateArgs);
14777
14778	UnsignedOrNone getNumArgumentsInExpansionFromUnexpanded(
14779	llvm::ArrayRef<UnexpandedParameterPack> Unexpanded,
14780	const MultiLevelTemplateArgumentList &TemplateArgs);
14781
14782	/// Determine whether the given declarator contains any unexpanded
14783	/// parameter packs.
14784	///
14785	/// This routine is used by the parser to disambiguate function declarators
14786	/// with an ellipsis prior to the ')', e.g.,
14787	///
14788	/// \code
14789	/// void f(T...);
14790	/// \endcode
14791	///
14792	/// To determine whether we have an (unnamed) function parameter pack or
14793	/// a variadic function.
14794	///
14795	/// \returns true if the declarator contains any unexpanded parameter packs,
14796	/// false otherwise.
14797	bool containsUnexpandedParameterPacks(Declarator &D);
14798
14799	/// Returns the pattern of the pack expansion for a template argument.
14800	///
14801	/// \param OrigLoc The template argument to expand.
14802	///
14803	/// \param Ellipsis Will be set to the location of the ellipsis.
14804	///
14805	/// \param NumExpansions Will be set to the number of expansions that will
14806	/// be generated from this pack expansion, if known a priori.
14807	TemplateArgumentLoc
14808	getTemplateArgumentPackExpansionPattern(TemplateArgumentLoc OrigLoc,
14809	SourceLocation &Ellipsis,
14810	UnsignedOrNone &NumExpansions) const;
14811
14812	/// Given a template argument that contains an unexpanded parameter pack, but
14813	/// which has already been substituted, attempt to determine the number of
14814	/// elements that will be produced once this argument is fully-expanded.
14815	///
14816	/// This is intended for use when transforming 'sizeof...(Arg)' in order to
14817	/// avoid actually expanding the pack where possible.
14818	UnsignedOrNone getFullyPackExpandedSize(TemplateArgument Arg);
14819
14820	/// Called when an expression computing the size of a parameter pack
14821	/// is parsed.
14822	///
14823	/// \code
14824	/// template<typename ...Types> struct count {
14825	/// static const unsigned value = sizeof...(Types);
14826	/// };
14827	/// \endcode
14828	///
14829	//
14830	/// \param OpLoc The location of the "sizeof" keyword.
14831	/// \param Name The name of the parameter pack whose size will be determined.
14832	/// \param NameLoc The source location of the name of the parameter pack.
14833	/// \param RParenLoc The location of the closing parentheses.
14834	ExprResult ActOnSizeofParameterPackExpr(Scope *S, SourceLocation OpLoc,
14835	IdentifierInfo &Name,
14836	SourceLocation NameLoc,
14837	SourceLocation RParenLoc);
14838
14839	ExprResult ActOnPackIndexingExpr(Scope S, Expr PackExpression,
14840	SourceLocation EllipsisLoc,
14841	SourceLocation LSquareLoc, Expr *IndexExpr,
14842	SourceLocation RSquareLoc);
14843
14844	ExprResult BuildPackIndexingExpr(Expr *PackExpression,
14845	SourceLocation EllipsisLoc, Expr *IndexExpr,
14846	SourceLocation RSquareLoc,
14847	ArrayRef<Expr *> ExpandedExprs = {},
14848	bool FullySubstituted = false);
14849
14850	/// Handle a C++1z fold-expression: ( expr op ... op expr ).
14851	ExprResult ActOnCXXFoldExpr(Scope S, SourceLocation LParenLoc, Expr LHS,
14852	tok::TokenKind Operator,
14853	SourceLocation EllipsisLoc, Expr *RHS,
14854	SourceLocation RParenLoc);
14855	ExprResult BuildCXXFoldExpr(UnresolvedLookupExpr *Callee,
14856	SourceLocation LParenLoc, Expr *LHS,
14857	BinaryOperatorKind Operator,
14858	SourceLocation EllipsisLoc, Expr *RHS,
14859	SourceLocation RParenLoc,
14860	UnsignedOrNone NumExpansions);
14861	ExprResult BuildEmptyCXXFoldExpr(SourceLocation EllipsisLoc,
14862	BinaryOperatorKind Operator);
14863
14864	///@}
14865
14866	//
14867	//
14868	// -------------------------------------------------------------------------
14869	//
14870	//
14871
14872	/// \name Constraints and Concepts
14873	/// Implementations are in SemaConcept.cpp
14874	///@{
14875
14876	public:
14877	ExprResult ActOnCXXReflectExpr(SourceLocation OpLoc, TypeSourceInfo *TSI);
14878
14879	ExprResult BuildCXXReflectExpr(SourceLocation OperatorLoc,
14880	TypeSourceInfo *TSI);
14881
14882	public:
14883	void PushSatisfactionStackEntry(const NamedDecl *D,
14884	const llvm::FoldingSetNodeID &ID) {
14885	const NamedDecl *Can = cast<NamedDecl>(Val: D->getCanonicalDecl());
14886	SatisfactionStack.emplace_back(Args&: Can, Args: ID);
14887	}
14888
14889	void PopSatisfactionStackEntry() { SatisfactionStack.pop_back(); }
14890
14891	bool SatisfactionStackContains(const NamedDecl *D,
14892	const llvm::FoldingSetNodeID &ID) const {
14893	const NamedDecl *Can = cast<NamedDecl>(Val: D->getCanonicalDecl());
14894	return llvm::is_contained(Range: SatisfactionStack,
14895	Element: SatisfactionStackEntryTy {Can, ID});
14896	}
14897
14898	using SatisfactionStackEntryTy =
14899	std::pair<const NamedDecl *, llvm::FoldingSetNodeID>;
14900
14901	// Resets the current SatisfactionStack for cases where we are instantiating
14902	// constraints as a 'side effect' of normal instantiation in a way that is not
14903	// indicative of recursive definition.
14904	class SatisfactionStackResetRAII {
14905	llvm::SmallVector<SatisfactionStackEntryTy, `10`> BackupSatisfactionStack;
14906	Sema &SemaRef;
14907
14908	public:
14909	SatisfactionStackResetRAII(Sema &S) : SemaRef(S) {
14910	SemaRef.SwapSatisfactionStack(NewSS&: BackupSatisfactionStack);
14911	}
14912
14913	~SatisfactionStackResetRAII() {
14914	SemaRef.SwapSatisfactionStack(NewSS&: BackupSatisfactionStack);
14915	}
14916
14917	SatisfactionStackResetRAII(const SatisfactionStackResetRAII &) = delete;
14918	SatisfactionStackResetRAII &
14919	operator=(const SatisfactionStackResetRAII &) = delete;
14920	};
14921
14922	void SwapSatisfactionStack(
14923	llvm::SmallVectorImpl<SatisfactionStackEntryTy> &NewSS) {
14924	SatisfactionStack.swap(RHS&: NewSS);
14925	}
14926
14927	using ConstrainedDeclOrNestedRequirement =
14928	llvm::PointerUnion<const NamedDecl *,
14929	const concepts::NestedRequirement *>;
14930
14931	/// Check whether the given expression is a valid constraint expression.
14932	/// A diagnostic is emitted if it is not, false is returned, and
14933	/// PossibleNonPrimary will be set to true if the failure might be due to a
14934	/// non-primary expression being used as an atomic constraint.
14935	bool CheckConstraintExpression(const Expr *CE, Token NextToken = Token (),
14936	bool PossibleNonPrimary = nullptr*,
14937	bool IsTrailingRequiresClause = false);
14938
14939	/// \brief Check whether the given list of constraint expressions are
14940	/// satisfied (as if in a 'conjunction') given template arguments.
14941	/// \param Template the template-like entity that triggered the constraints
14942	/// check (either a concept or a constrained entity).
14943	/// \param ConstraintExprs a list of constraint expressions, treated as if
14944	/// they were 'AND'ed together.
14945	/// \param TemplateArgLists the list of template arguments to substitute into
14946	/// the constraint expression.
14947	/// \param TemplateIDRange The source range of the template id that
14948	/// caused the constraints check.
14949	/// \param Satisfaction if true is returned, will contain details of the
14950	/// satisfaction, with enough information to diagnose an unsatisfied
14951	/// expression.
14952	/// \returns true if an error occurred and satisfaction could not be checked,
14953	/// false otherwise.
14954	bool CheckConstraintSatisfaction(
14955	ConstrainedDeclOrNestedRequirement Entity,
14956	ArrayRef<AssociatedConstraint> AssociatedConstraints,
14957	const MultiLevelTemplateArgumentList &TemplateArgLists,
14958	SourceRange TemplateIDRange, ConstraintSatisfaction &Satisfaction,
14959	const ConceptReference TopLevelConceptId = nullptr*,
14960	Expr ConvertedExpr = nullptr**);
14961
14962	/// Check whether the given function decl's trailing requires clause is
14963	/// satisfied, if any. Returns false and updates Satisfaction with the
14964	/// satisfaction verdict if successful, emits a diagnostic and returns true if
14965	/// an error occurred and satisfaction could not be determined.
14966	///
14967	/// \returns true if an error occurred, false otherwise.
14968	bool CheckFunctionConstraints(const FunctionDecl *FD,
14969	ConstraintSatisfaction &Satisfaction,
14970	SourceLocation UsageLoc = SourceLocation (),
14971	bool ForOverloadResolution = false);
14972
14973	// Calculates whether two constraint expressions are equal irrespective of a
14974	// difference in 'depth'. This takes a pair of optional 'NamedDecl's 'Old' and
14975	// 'New', which are the "source" of the constraint, since this is necessary
14976	// for figuring out the relative 'depth' of the constraint. The depth of the
14977	// 'primary template' and the 'instantiated from' templates aren't necessarily
14978	// the same, such as a case when one is a 'friend' defined in a class.
14979	bool AreConstraintExpressionsEqual(const NamedDecl *Old,
14980	const Expr *OldConstr,
14981	const TemplateCompareNewDeclInfo &New,
14982	const Expr *NewConstr);
14983
14984	// Calculates whether the friend function depends on an enclosing template for
14985	// the purposes of [temp.friend] p9.
14986	bool FriendConstraintsDependOnEnclosingTemplate(const FunctionDecl *FD);
14987
14988	/// \brief Ensure that the given template arguments satisfy the constraints
14989	/// associated with the given template, emitting a diagnostic if they do not.
14990	///
14991	/// \param Template The template to which the template arguments are being
14992	/// provided.
14993	///
14994	/// \param TemplateArgs The converted, canonicalized template arguments.
14995	///
14996	/// \param TemplateIDRange The source range of the template id that
14997	/// caused the constraints check.
14998	///
14999	/// \returns true if the constrains are not satisfied or could not be checked
15000	/// for satisfaction, false if the constraints are satisfied.
15001	bool EnsureTemplateArgumentListConstraints(
15002	TemplateDecl *Template,
15003	const MultiLevelTemplateArgumentList &TemplateArgs,
15004	SourceRange TemplateIDRange);
15005
15006	bool CheckFunctionTemplateConstraints(SourceLocation PointOfInstantiation,
15007	FunctionDecl *Decl,
15008	ArrayRef<TemplateArgument> TemplateArgs,
15009	ConstraintSatisfaction &Satisfaction);
15010
15011	/// \brief Emit diagnostics explaining why a constraint expression was deemed
15012	/// unsatisfied.
15013	/// \param First whether this is the first time an unsatisfied constraint is
15014	/// diagnosed for this error.
15015	void DiagnoseUnsatisfiedConstraint(const ConstraintSatisfaction &Satisfaction,
15016	SourceLocation Loc = {},
15017	bool First = true);
15018
15019	/// \brief Emit diagnostics explaining why a constraint expression was deemed
15020	/// unsatisfied.
15021	void
15022	DiagnoseUnsatisfiedConstraint(const ConceptSpecializationExpr *ConstraintExpr,
15023	bool First = true);
15024
15025	const NormalizedConstraint *getNormalizedAssociatedConstraints(
15026	ConstrainedDeclOrNestedRequirement Entity,
15027	ArrayRef<AssociatedConstraint> AssociatedConstraints);
15028
15029	/// \brief Check whether the given declaration's associated constraints are
15030	/// at least as constrained than another declaration's according to the
15031	/// partial ordering of constraints.
15032	///
15033	/// \param Result If no error occurred, receives the result of true if D1 is
15034	/// at least constrained than D2, and false otherwise.
15035	///
15036	/// \returns true if an error occurred, false otherwise.
15037	bool IsAtLeastAsConstrained(const NamedDecl *D1,
15038	MutableArrayRef<AssociatedConstraint> AC1,
15039	const NamedDecl *D2,
15040	MutableArrayRef<AssociatedConstraint> AC2,
15041	bool &Result);
15042
15043	/// If D1 was not at least as constrained as D2, but would've been if a pair
15044	/// of atomic constraints involved had been declared in a concept and not
15045	/// repeated in two separate places in code.
15046	/// \returns true if such a diagnostic was emitted, false otherwise.
15047	bool MaybeEmitAmbiguousAtomicConstraintsDiagnostic(
15048	const NamedDecl *D1, ArrayRef<AssociatedConstraint> AC1,
15049	const NamedDecl *D2, ArrayRef<AssociatedConstraint> AC2);
15050
15051	/// Cache the satisfaction of an atomic constraint.
15052	/// The key is based on the unsubstituted expression and the parameter
15053	/// mapping. This lets us not substituting the mapping more than once,
15054	/// which is (very!) expensive.
15055	/// FIXME: this should be private.
15056	llvm::DenseMap<llvm::FoldingSetNodeID,
15057	UnsubstitutedConstraintSatisfactionCacheResult>
15058	UnsubstitutedConstraintSatisfactionCache;
15059
15060	private:
15061	/// Caches pairs of template-like decls whose associated constraints were
15062	/// checked for subsumption and whether or not the first's constraints did in
15063	/// fact subsume the second's.
15064	llvm::DenseMap<std::pair<const NamedDecl , const* NamedDecl >, bool*>
15065	SubsumptionCache;
15066	/// Caches the normalized associated constraints of declarations (concepts or
15067	/// constrained declarations). If an error occurred while normalizing the
15068	/// associated constraints of the template or concept, nullptr will be cached
15069	/// here.
15070	llvm::DenseMap<ConstrainedDeclOrNestedRequirement, NormalizedConstraint *>
15071	NormalizationCache;
15072
15073	/// Cache whether the associated constraint of a declaration
15074	/// is satisfied.
15075	llvm::ContextualFoldingSet<ConstraintSatisfaction, const ASTContext &>
15076	SatisfactionCache;
15077
15078	// The current stack of constraint satisfactions, so we can exit-early.
15079	llvm::SmallVector<SatisfactionStackEntryTy, `10`> SatisfactionStack;
15080
15081	/// Used by SetupConstraintCheckingTemplateArgumentsAndScope to set up the
15082	/// LocalInstantiationScope of the current non-lambda function. For lambdas,
15083	/// use LambdaScopeForCallOperatorInstantiationRAII.
15084	bool
15085	SetupConstraintScope(FunctionDecl *FD,
15086	std::optional<ArrayRef<TemplateArgument>> TemplateArgs,
15087	const MultiLevelTemplateArgumentList &MLTAL,
15088	LocalInstantiationScope &Scope);
15089
15090	/// Used during constraint checking, sets up the constraint template argument
15091	/// lists, and calls SetupConstraintScope to set up the
15092	/// LocalInstantiationScope to have the proper set of ParVarDecls configured.
15093	std::optional<MultiLevelTemplateArgumentList>
15094	SetupConstraintCheckingTemplateArgumentsAndScope(
15095	FunctionDecl *FD, std::optional<ArrayRef<TemplateArgument>> TemplateArgs,
15096	LocalInstantiationScope &Scope);
15097
15098	///@}
15099
15100	//
15101	//
15102	// -------------------------------------------------------------------------
15103	//
15104	//
15105
15106	/// \name Types
15107	/// Implementations are in SemaType.cpp
15108	///@{
15109
15110	public:
15111	/// A mapping that describes the nullability we've seen in each header file.
15112	FileNullabilityMap NullabilityMap;
15113
15114	static int getPrintable(int I) { return I; }
15115	static unsigned getPrintable(unsigned I) { return I; }
15116	static bool getPrintable(bool B) { return B; }
15117	static const char getPrintable(const* char S) { return* S; }
15118	static StringRef getPrintable(StringRef S) { return S; }
15119	static const std::string &getPrintable(const std::string &S) { return S; }
15120	static const IdentifierInfo getPrintable(const* IdentifierInfo *II) {
15121	return II;
15122	}
15123	static DeclarationName getPrintable(DeclarationName N) { return N; }
15124	static QualType getPrintable(QualType T) { return T; }
15125	static SourceRange getPrintable(SourceRange R) { return R; }
15126	static SourceRange getPrintable(SourceLocation L) { return L; }
15127	static SourceRange getPrintable(const Expr E) { return* E->getSourceRange(); }
15128	static SourceRange getPrintable(TypeLoc TL) { return TL.getSourceRange(); }
15129
15130	enum class CompleteTypeKind {
15131	/// Apply the normal rules for complete types. In particular,
15132	/// treat all sizeless types as incomplete.
15133	Normal,
15134
15135	/// Relax the normal rules for complete types so that they include
15136	/// sizeless built-in types.
15137	AcceptSizeless,
15138
15139	// FIXME: Eventually we should flip the default to Normal and opt in
15140	// to AcceptSizeless rather than opt out of it.
15141	Default = AcceptSizeless
15142	};
15143
15144	QualType BuildQualifiedType(QualType T, SourceLocation Loc, Qualifiers Qs,
15145	const DeclSpec DS = nullptr*);
15146	QualType BuildQualifiedType(QualType T, SourceLocation Loc, unsigned CVRA,
15147	const DeclSpec DS = nullptr*);
15148
15149	/// Build a pointer type.
15150	///
15151	/// \param T The type to which we'll be building a pointer.
15152	///
15153	/// \param Loc The location of the entity whose type involves this
15154	/// pointer type or, if there is no such entity, the location of the
15155	/// type that will have pointer type.
15156	///
15157	/// \param Entity The name of the entity that involves the pointer
15158	/// type, if known.
15159	///
15160	/// \returns A suitable pointer type, if there are no
15161	/// errors. Otherwise, returns a NULL type.
15162	QualType BuildPointerType(QualType T, SourceLocation Loc,
15163	DeclarationName Entity);
15164
15165	/// Build a reference type.
15166	///
15167	/// \param T The type to which we'll be building a reference.
15168	///
15169	/// \param Loc The location of the entity whose type involves this
15170	/// reference type or, if there is no such entity, the location of the
15171	/// type that will have reference type.
15172	///
15173	/// \param Entity The name of the entity that involves the reference
15174	/// type, if known.
15175	///
15176	/// \returns A suitable reference type, if there are no
15177	/// errors. Otherwise, returns a NULL type.
15178	QualType BuildReferenceType(QualType T, bool LValueRef, SourceLocation Loc,
15179	DeclarationName Entity);
15180
15181	/// Build an array type.
15182	///
15183	/// \param T The type of each element in the array.
15184	///
15185	/// \param ASM C99 array size modifier (e.g., '', 'static').*
15186	///
15187	/// \param ArraySize Expression describing the size of the array.
15188	///
15189	/// \param Brackets The range from the opening '[' to the closing ']'.
15190	///
15191	/// \param Entity The name of the entity that involves the array
15192	/// type, if known.
15193	///
15194	/// \returns A suitable array type, if there are no errors. Otherwise,
15195	/// returns a NULL type.
15196	QualType BuildArrayType(QualType T, ArraySizeModifier ASM, Expr *ArraySize,
15197	unsigned Quals, SourceRange Brackets,
15198	DeclarationName Entity);
15199	QualType BuildVectorType(QualType T, Expr *VecSize, SourceLocation AttrLoc);
15200
15201	/// Build an ext-vector type.
15202	///
15203	/// Run the required checks for the extended vector type.
15204	QualType BuildExtVectorType(QualType T, Expr *ArraySize,
15205	SourceLocation AttrLoc);
15206	QualType BuildMatrixType(QualType T, Expr NumRows, Expr NumColumns,
15207	SourceLocation AttrLoc);
15208
15209	QualType BuildCountAttributedArrayOrPointerType(QualType WrappedTy,
15210	Expr *CountExpr,
15211	bool CountInBytes,
15212	bool OrNull);
15213
15214	/// BuildAddressSpaceAttr - Builds a DependentAddressSpaceType if an
15215	/// expression is uninstantiated. If instantiated it will apply the
15216	/// appropriate address space to the type. This function allows dependent
15217	/// template variables to be used in conjunction with the address_space
15218	/// attribute
15219	QualType BuildAddressSpaceAttr(QualType &T, LangAS ASIdx, Expr *AddrSpace,
15220	SourceLocation AttrLoc);
15221
15222	/// Same as above, but constructs the AddressSpace index if not provided.
15223	QualType BuildAddressSpaceAttr(QualType &T, Expr *AddrSpace,
15224	SourceLocation AttrLoc);
15225
15226	bool CheckQualifiedFunctionForTypeId(QualType T, SourceLocation Loc);
15227
15228	bool CheckFunctionReturnType(QualType T, SourceLocation Loc);
15229
15230	/// Build a function type.
15231	///
15232	/// This routine checks the function type according to C++ rules and
15233	/// under the assumption that the result type and parameter types have
15234	/// just been instantiated from a template. It therefore duplicates
15235	/// some of the behavior of GetTypeForDeclarator, but in a much
15236	/// simpler form that is only suitable for this narrow use case.
15237	///
15238	/// \param T The return type of the function.
15239	///
15240	/// \param ParamTypes The parameter types of the function. This array
15241	/// will be modified to account for adjustments to the types of the
15242	/// function parameters.
15243	///
15244	/// \param Loc The location of the entity whose type involves this
15245	/// function type or, if there is no such entity, the location of the
15246	/// type that will have function type.
15247	///
15248	/// \param Entity The name of the entity that involves the function
15249	/// type, if known.
15250	///
15251	/// \param EPI Extra information about the function type. Usually this will
15252	/// be taken from an existing function with the same prototype.
15253	///
15254	/// \returns A suitable function type, if there are no errors. The
15255	/// unqualified type will always be a FunctionProtoType.
15256	/// Otherwise, returns a NULL type.
15257	QualType BuildFunctionType(QualType T, MutableArrayRef<QualType> ParamTypes,
15258	SourceLocation Loc, DeclarationName Entity,
15259	const FunctionProtoType::ExtProtoInfo &EPI);
15260
15261	/// Build a member pointer type \c T Class::.*
15262	///
15263	/// \param T the type to which the member pointer refers.
15264	/// \param Class the class type into which the member pointer points.
15265	/// \param Loc the location where this type begins
15266	/// \param Entity the name of the entity that will have this member pointer
15267	/// type
15268	///
15269	/// \returns a member pointer type, if successful, or a NULL type if there was
15270	/// an error.
15271	QualType BuildMemberPointerType(QualType T, const CXXScopeSpec &SS,
15272	CXXRecordDecl *Cls, SourceLocation Loc,
15273	DeclarationName Entity);
15274
15275	/// Build a block pointer type.
15276	///
15277	/// \param T The type to which we'll be building a block pointer.
15278	///
15279	/// \param Loc The source location, used for diagnostics.
15280	///
15281	/// \param Entity The name of the entity that involves the block pointer
15282	/// type, if known.
15283	///
15284	/// \returns A suitable block pointer type, if there are no
15285	/// errors. Otherwise, returns a NULL type.
15286	QualType BuildBlockPointerType(QualType T, SourceLocation Loc,
15287	DeclarationName Entity);
15288
15289	/// Build a paren type including \p T.
15290	QualType BuildParenType(QualType T);
15291	QualType BuildAtomicType(QualType T, SourceLocation Loc);
15292
15293	/// Build a Read-only Pipe type.
15294	///
15295	/// \param T The type to which we'll be building a Pipe.
15296	///
15297	/// \param Loc We do not use it for now.
15298	///
15299	/// \returns A suitable pipe type, if there are no errors. Otherwise, returns
15300	/// a NULL type.
15301	QualType BuildReadPipeType(QualType T, SourceLocation Loc);
15302
15303	/// Build a Write-only Pipe type.
15304	///
15305	/// \param T The type to which we'll be building a Pipe.
15306	///
15307	/// \param Loc We do not use it for now.
15308	///
15309	/// \returns A suitable pipe type, if there are no errors. Otherwise, returns
15310	/// a NULL type.
15311	QualType BuildWritePipeType(QualType T, SourceLocation Loc);
15312
15313	/// Build a bit-precise integer type.
15314	///
15315	/// \param IsUnsigned Boolean representing the signedness of the type.
15316	///
15317	/// \param BitWidth Size of this int type in bits, or an expression
15318	/// representing that.
15319	///
15320	/// \param Loc Location of the keyword.
15321	QualType BuildBitIntType(bool IsUnsigned, Expr *BitWidth, SourceLocation Loc);
15322
15323	/// GetTypeForDeclarator - Convert the type for the specified
15324	/// declarator to Type instances.
15325	///
15326	/// The result of this call will never be null, but the associated
15327	/// type may be a null type if there's an unrecoverable error.
15328	TypeSourceInfo *GetTypeForDeclarator(Declarator &D);
15329	TypeSourceInfo *GetTypeForDeclaratorCast(Declarator &D, QualType FromTy);
15330
15331	/// Package the given type and TSI into a ParsedType.
15332	ParsedType CreateParsedType(QualType T, TypeSourceInfo *TInfo);
15333	static QualType GetTypeFromParser(ParsedType Ty,
15334	TypeSourceInfo TInfo = nullptr**);
15335
15336	TypeResult ActOnTypeName(Declarator &D);
15337
15338	// Check whether the size of array element of type \p EltTy is a multiple of
15339	// its alignment and return false if it isn't.
15340	bool checkArrayElementAlignment(QualType EltTy, SourceLocation Loc);
15341
15342	void
15343	diagnoseIgnoredQualifiers(unsigned DiagID, unsigned Quals,
15344	SourceLocation FallbackLoc,
15345	SourceLocation ConstQualLoc = SourceLocation (),
15346	SourceLocation VolatileQualLoc = SourceLocation (),
15347	SourceLocation RestrictQualLoc = SourceLocation (),
15348	SourceLocation AtomicQualLoc = SourceLocation (),
15349	SourceLocation UnalignedQualLoc = SourceLocation ());
15350
15351	/// Retrieve the keyword associated
15352	IdentifierInfo *getNullabilityKeyword(NullabilityKind nullability);
15353
15354	/// Adjust the calling convention of a method to be the ABI default if it
15355	/// wasn't specified explicitly. This handles method types formed from
15356	/// function type typedefs and typename template arguments.
15357	void adjustMemberFunctionCC(QualType &T, bool HasThisPointer,
15358	bool IsCtorOrDtor, SourceLocation Loc);
15359
15360	// Check if there is an explicit attribute, but only look through parens.
15361	// The intent is to look for an attribute on the current declarator, but not
15362	// one that came from a typedef.
15363	bool hasExplicitCallingConv(QualType T);
15364
15365	/// Check whether a nullability type specifier can be added to the given
15366	/// type through some means not written in source (e.g. API notes).
15367	///
15368	/// \param Type The type to which the nullability specifier will be
15369	/// added. On success, this type will be updated appropriately.
15370	///
15371	/// \param Nullability The nullability specifier to add.
15372	///
15373	/// \param DiagLoc The location to use for diagnostics.
15374	///
15375	/// \param AllowArrayTypes Whether to accept nullability specifiers on an
15376	/// array type (e.g., because it will decay to a pointer).
15377	///
15378	/// \param OverrideExisting Whether to override an existing, locally-specified
15379	/// nullability specifier rather than complaining about the conflict.
15380	///
15381	/// \returns true if nullability cannot be applied, false otherwise.
15382	bool CheckImplicitNullabilityTypeSpecifier(QualType &Type,
15383	NullabilityKind Nullability,
15384	SourceLocation DiagLoc,
15385	bool AllowArrayTypes,
15386	bool OverrideExisting);
15387
15388	/// Check whether the given variable declaration has a size that fits within
15389	/// the address space it is declared in. This issues a diagnostic if not.
15390	///
15391	/// \param VD The variable declaration to check the size of.
15392	///
15393	/// \param AS The address space to check the size of \p VD against.
15394	///
15395	/// \returns true if the variable's size fits within the address space, false
15396	/// otherwise.
15397	bool CheckVarDeclSizeAddressSpace(const VarDecl *VD, LangAS AS);
15398
15399	/// Get the type of expression E, triggering instantiation to complete the
15400	/// type if necessary -- that is, if the expression refers to a templated
15401	/// static data member of incomplete array type.
15402	///
15403	/// May still return an incomplete type if instantiation was not possible or
15404	/// if the type is incomplete for a different reason. Use
15405	/// RequireCompleteExprType instead if a diagnostic is expected for an
15406	/// incomplete expression type.
15407	QualType getCompletedType(Expr *E);
15408
15409	void completeExprArrayBound(Expr *E);
15410
15411	/// Ensure that the type of the given expression is complete.
15412	///
15413	/// This routine checks whether the expression \p E has a complete type. If
15414	/// the expression refers to an instantiable construct, that instantiation is
15415	/// performed as needed to complete its type. Furthermore
15416	/// Sema::RequireCompleteType is called for the expression's type (or in the
15417	/// case of a reference type, the referred-to type).
15418	///
15419	/// \param E The expression whose type is required to be complete.
15420	/// \param Kind Selects which completeness rules should be applied.
15421	/// \param Diagnoser The object that will emit a diagnostic if the type is
15422	/// incomplete.
15423	///
15424	/// \returns \c true if the type of \p E is incomplete and diagnosed, \c false
15425	/// otherwise.
15426	bool RequireCompleteExprType(Expr *E, CompleteTypeKind Kind,
15427	TypeDiagnoser &Diagnoser);
15428	bool RequireCompleteExprType(Expr E, unsigned* DiagID);
15429
15430	template <typename... Ts>
15431	bool RequireCompleteExprType(Expr E, unsigned* DiagID, const Ts &...Args) {
15432	BoundTypeDiagnoser<Ts...> Diagnoser(DiagID, Args...);
15433	return RequireCompleteExprType(E, CompleteTypeKind::Default, Diagnoser);
15434	}
15435
15436	// Returns the underlying type of a decltype with the given expression.
15437	QualType getDecltypeForExpr(Expr *E);
15438
15439	QualType BuildTypeofExprType(Expr *E, TypeOfKind Kind);
15440	/// If AsUnevaluated is false, E is treated as though it were an evaluated
15441	/// context, such as when building a type for decltype(auto).
15442	QualType BuildDecltypeType(Expr E, bool* AsUnevaluated = true);
15443
15444	QualType ActOnPackIndexingType(QualType Pattern, Expr *IndexExpr,
15445	SourceLocation Loc,
15446	SourceLocation EllipsisLoc);
15447	QualType BuildPackIndexingType(QualType Pattern, Expr *IndexExpr,
15448	SourceLocation Loc, SourceLocation EllipsisLoc,
15449	bool FullySubstituted = false,
15450	ArrayRef<QualType> Expansions = {});
15451
15452	using UTTKind = UnaryTransformType::UTTKind;
15453	QualType BuildUnaryTransformType(QualType BaseType, UTTKind UKind,
15454	SourceLocation Loc);
15455	QualType BuiltinEnumUnderlyingType(QualType BaseType, SourceLocation Loc);
15456	QualType BuiltinAddPointer(QualType BaseType, SourceLocation Loc);
15457	QualType BuiltinRemovePointer(QualType BaseType, SourceLocation Loc);
15458	QualType BuiltinDecay(QualType BaseType, SourceLocation Loc);
15459	QualType BuiltinAddReference(QualType BaseType, UTTKind UKind,
15460	SourceLocation Loc);
15461	QualType BuiltinRemoveExtent(QualType BaseType, UTTKind UKind,
15462	SourceLocation Loc);
15463	QualType BuiltinRemoveReference(QualType BaseType, UTTKind UKind,
15464	SourceLocation Loc);
15465
15466	QualType BuiltinRemoveCVRef(QualType BaseType, SourceLocation Loc) {
15467	return BuiltinRemoveReference(BaseType, UKind: UTTKind::RemoveCVRef, Loc);
15468	}
15469
15470	QualType BuiltinChangeCVRQualifiers(QualType BaseType, UTTKind UKind,
15471	SourceLocation Loc);
15472	QualType BuiltinChangeSignedness(QualType BaseType, UTTKind UKind,
15473	SourceLocation Loc);
15474
15475	bool BuiltinIsBaseOf(SourceLocation RhsTLoc, QualType LhsT, QualType RhsT);
15476
15477	/// Ensure that the type T is a literal type.
15478	///
15479	/// This routine checks whether the type @p T is a literal type. If @p T is an
15480	/// incomplete type, an attempt is made to complete it. If @p T is a literal
15481	/// type, or @p AllowIncompleteType is true and @p T is an incomplete type,
15482	/// returns false. Otherwise, this routine issues the diagnostic @p PD (giving
15483	/// it the type @p T), along with notes explaining why the type is not a
15484	/// literal type, and returns true.
15485	///
15486	/// @param Loc The location in the source that the non-literal type
15487	/// diagnostic should refer to.
15488	///
15489	/// @param T The type that this routine is examining for literalness.
15490	///
15491	/// @param Diagnoser Emits a diagnostic if T is not a literal type.
15492	///
15493	/// @returns @c true if @p T is not a literal type and a diagnostic was
15494	/// emitted, @c false otherwise.
15495	bool RequireLiteralType(SourceLocation Loc, QualType T,
15496	TypeDiagnoser &Diagnoser);
15497	bool RequireLiteralType(SourceLocation Loc, QualType T, unsigned DiagID);
15498
15499	template <typename... Ts>
15500	bool RequireLiteralType(SourceLocation Loc, QualType T, unsigned DiagID,
15501	const Ts &...Args) {
15502	BoundTypeDiagnoser<Ts...> Diagnoser(DiagID, Args...);
15503	return RequireLiteralType(Loc, T, Diagnoser);
15504	}
15505
15506	bool isCompleteType(SourceLocation Loc, QualType T,
15507	CompleteTypeKind Kind = CompleteTypeKind::Default) {
15508	return !RequireCompleteTypeImpl(Loc, T, Kind, Diagnoser: nullptr);
15509	}
15510
15511	/// Ensure that the type T is a complete type.
15512	///
15513	/// This routine checks whether the type @p T is complete in any
15514	/// context where a complete type is required. If @p T is a complete
15515	/// type, returns false. If @p T is a class template specialization,
15516	/// this routine then attempts to perform class template
15517	/// instantiation. If instantiation fails, or if @p T is incomplete
15518	/// and cannot be completed, issues the diagnostic @p diag (giving it
15519	/// the type @p T) and returns true.
15520	///
15521	/// @param Loc The location in the source that the incomplete type
15522	/// diagnostic should refer to.
15523	///
15524	/// @param T The type that this routine is examining for completeness.
15525	///
15526	/// @param Kind Selects which completeness rules should be applied.
15527	///
15528	/// @returns @c true if @p T is incomplete and a diagnostic was emitted,
15529	/// @c false otherwise.
15530	bool RequireCompleteType(SourceLocation Loc, QualType T,
15531	CompleteTypeKind Kind, TypeDiagnoser &Diagnoser);
15532	bool RequireCompleteType(SourceLocation Loc, QualType T,
15533	CompleteTypeKind Kind, unsigned DiagID);
15534
15535	bool RequireCompleteType(SourceLocation Loc, QualType T,
15536	TypeDiagnoser &Diagnoser) {
15537	return RequireCompleteType(Loc, T, Kind: CompleteTypeKind::Default, Diagnoser);
15538	}
15539	bool RequireCompleteType(SourceLocation Loc, QualType T, unsigned DiagID) {
15540	return RequireCompleteType(Loc, T, Kind: CompleteTypeKind::Default, DiagID);
15541	}
15542
15543	template <typename... Ts>
15544	bool RequireCompleteType(SourceLocation Loc, QualType T, unsigned DiagID,
15545	const Ts &...Args) {
15546	BoundTypeDiagnoser<Ts...> Diagnoser(DiagID, Args...);
15547	return RequireCompleteType(Loc, T, Diagnoser);
15548	}
15549
15550	/// Determine whether a declaration is visible to name lookup.
15551	bool isVisible(const NamedDecl *D) {
15552	return D->isUnconditionallyVisible() \|\|
15553	isAcceptableSlow(D, Kind: AcceptableKind::Visible);
15554	}
15555
15556	/// Determine whether a declaration is reachable.
15557	bool isReachable(const NamedDecl *D) {
15558	// All visible declarations are reachable.
15559	return D->isUnconditionallyVisible() \|\|
15560	isAcceptableSlow(D, Kind: AcceptableKind::Reachable);
15561	}
15562
15563	/// Determine whether a declaration is acceptable (visible/reachable).
15564	bool isAcceptable(const NamedDecl *D, AcceptableKind Kind) {
15565	return Kind == AcceptableKind::Visible ? isVisible(D) : isReachable(D);
15566	}
15567
15568	/// Determine if \p D and \p Suggested have a structurally compatible
15569	/// layout as described in C11 6.2.7/1.
15570	bool hasStructuralCompatLayout(Decl D, Decl Suggested);
15571
15572	/// Determine if \p D has a visible definition. If not, suggest a declaration
15573	/// that should be made visible to expose the definition.
15574	bool hasVisibleDefinition(NamedDecl D, NamedDecl *Suggested,
15575	bool OnlyNeedComplete = false);
15576	bool hasVisibleDefinition(const NamedDecl *D) {
15577	NamedDecl *Hidden;
15578	return hasVisibleDefinition(D: const_cast<NamedDecl *>(D), Suggested: &Hidden);
15579	}
15580	/// Determine if \p D has a definition which allows we redefine it in current
15581	/// TU. \p Suggested is the definition that should be made visible to expose
15582	/// the definition.
15583	bool isRedefinitionAllowedFor(NamedDecl D, NamedDecl *Suggested,
15584	bool &Visible);
15585	bool isRedefinitionAllowedFor(const NamedDecl D, bool* &Visible) {
15586	NamedDecl *Hidden;
15587	return isRedefinitionAllowedFor(D: const_cast<NamedDecl *>(D), Suggested: &Hidden,
15588	Visible);
15589	}
15590
15591	/// Determine if \p D has a reachable definition. If not, suggest a
15592	/// declaration that should be made reachable to expose the definition.
15593	bool hasReachableDefinition(NamedDecl D, NamedDecl *Suggested,
15594	bool OnlyNeedComplete = false);
15595	bool hasReachableDefinition(NamedDecl *D) {
15596	NamedDecl *Hidden;
15597	return hasReachableDefinition(D, Suggested: &Hidden);
15598	}
15599
15600	bool hasAcceptableDefinition(NamedDecl D, NamedDecl *Suggested,
15601	AcceptableKind Kind,
15602	bool OnlyNeedComplete = false);
15603	bool hasAcceptableDefinition(NamedDecl *D, AcceptableKind Kind) {
15604	NamedDecl *Hidden;
15605	return hasAcceptableDefinition(D, Suggested: &Hidden, Kind);
15606	}
15607
15608	/// Try to parse the conditional expression attached to an effect attribute
15609	/// (e.g. 'nonblocking'). (c.f. Sema::ActOnNoexceptSpec). Return an empty
15610	/// optional on error.
15611	std::optional<FunctionEffectMode>
15612	ActOnEffectExpression(Expr *CondExpr, StringRef AttributeName);
15613
15614	void ActOnCleanupAttr(Decl D, const* Attr *A);
15615	void ActOnInitPriorityAttr(Decl D, const* Attr *A);
15616
15617	private:
15618	/// The implementation of RequireCompleteType
15619	bool RequireCompleteTypeImpl(SourceLocation Loc, QualType T,
15620	CompleteTypeKind Kind, TypeDiagnoser *Diagnoser);
15621
15622	/// Nullability type specifiers.
15623	IdentifierInfo Ident__Nonnull = nullptr*;
15624	IdentifierInfo Ident__Nullable = nullptr*;
15625	IdentifierInfo Ident__Nullable_result = nullptr*;
15626	IdentifierInfo Ident__Null_unspecified = nullptr*;
15627
15628	///@}
15629
15630	//
15631	//
15632	// -------------------------------------------------------------------------
15633	//
15634	//
15635
15636	/// \name FixIt Helpers
15637	/// Implementations are in SemaFixItUtils.cpp
15638	///@{
15639
15640	public:
15641	/// Get a string to suggest for zero-initialization of a type.
15642	std::string getFixItZeroInitializerForType(QualType T,
15643	SourceLocation Loc) const;
15644	std::string getFixItZeroLiteralForType(QualType T, SourceLocation Loc) const;
15645
15646	///@}
15647
15648	//
15649	//
15650	// -------------------------------------------------------------------------
15651	//
15652	//
15653
15654	/// \name Function Effects
15655	/// Implementations are in SemaFunctionEffects.cpp
15656	///@{
15657	public:
15658	struct FunctionEffectDiff {
15659	enum class Kind { Added, Removed, ConditionMismatch };
15660
15661	FunctionEffect::Kind EffectKind;
15662	Kind DiffKind;
15663	std::optional<FunctionEffectWithCondition>
15664	Old; // Invalid when 'Kind' is 'Added'.
15665	std::optional<FunctionEffectWithCondition>
15666	New; // Invalid when 'Kind' is 'Removed'.
15667
15668	StringRef effectName() const {
15669	if (Old)
15670	return Old.value().Effect.name();
15671	return New.value().Effect.name();
15672	}
15673
15674	/// Describes the result of effects differing between a base class's virtual
15675	/// method and an overriding method in a subclass.
15676	enum class OverrideResult {
15677	NoAction,
15678	Warn,
15679	Merge // Merge missing effect from base to derived.
15680	};
15681
15682	/// Return true if adding or removing the effect as part of a type
15683	/// conversion should generate a diagnostic.
15684	bool shouldDiagnoseConversion(QualType SrcType,
15685	const FunctionEffectsRef &SrcFX,
15686	QualType DstType,
15687	const FunctionEffectsRef &DstFX) const;
15688
15689	/// Return true if adding or removing the effect in a redeclaration should
15690	/// generate a diagnostic.
15691	bool shouldDiagnoseRedeclaration(const FunctionDecl &OldFunction,
15692	const FunctionEffectsRef &OldFX,
15693	const FunctionDecl &NewFunction,
15694	const FunctionEffectsRef &NewFX) const;
15695
15696	/// Return true if adding or removing the effect in a C++ virtual method
15697	/// override should generate a diagnostic.
15698	OverrideResult shouldDiagnoseMethodOverride(
15699	const CXXMethodDecl &OldMethod, const FunctionEffectsRef &OldFX,
15700	const CXXMethodDecl &NewMethod, const FunctionEffectsRef &NewFX) const;
15701	};
15702
15703	struct FunctionEffectDiffVector : public SmallVector<FunctionEffectDiff> {
15704	/// Caller should short-circuit by checking for equality first.
15705	FunctionEffectDiffVector(const FunctionEffectsRef &Old,
15706	const FunctionEffectsRef &New);
15707	};
15708
15709	/// All functions/lambdas/blocks which have bodies and which have a non-empty
15710	/// FunctionEffectsRef to be verified.
15711	SmallVector<const Decl *> DeclsWithEffectsToVerify;
15712
15713	/// The union of all effects present on DeclsWithEffectsToVerify. Conditions
15714	/// are all null.
15715	FunctionEffectKindSet AllEffectsToVerify;
15716
15717	public:
15718	/// Warn and return true if adding a function effect to a set would create a
15719	/// conflict.
15720	bool diagnoseConflictingFunctionEffect(const FunctionEffectsRef &FX,
15721	const FunctionEffectWithCondition &EC,
15722	SourceLocation NewAttrLoc);
15723
15724	// Report a failure to merge function effects between declarations due to a
15725	// conflict.
15726	void
15727	diagnoseFunctionEffectMergeConflicts(const FunctionEffectSet::Conflicts &Errs,
15728	SourceLocation NewLoc,
15729	SourceLocation OldLoc);
15730
15731	/// Inline checks from the start of maybeAddDeclWithEffects, to
15732	/// minimize performance impact on code not using effects.
15733	template <class FuncOrBlockDecl>
15734	void maybeAddDeclWithEffects(FuncOrBlockDecl *D) {
15735	if (Context.hasAnyFunctionEffects())
15736	if (FunctionEffectsRef FX = D->getFunctionEffects(); !FX.empty())
15737	maybeAddDeclWithEffects(D, FX);
15738	}
15739
15740	/// Potentially add a FunctionDecl or BlockDecl to DeclsWithEffectsToVerify.
15741	void maybeAddDeclWithEffects(const Decl D, const* FunctionEffectsRef &FX);
15742
15743	/// Unconditionally add a Decl to DeclsWithEfffectsToVerify.
15744	void addDeclWithEffects(const Decl D, const* FunctionEffectsRef &FX);
15745
15746	void performFunctionEffectAnalysis(TranslationUnitDecl *TU);
15747
15748	///@}
15749	};
15750
15751	DeductionFailureInfo
15752	MakeDeductionFailureInfo(ASTContext &Context, TemplateDeductionResult TDK,
15753	sema::TemplateDeductionInfo &Info);
15754
15755	/// Contains a late templated function.
15756	/// Will be parsed at the end of the translation unit, used by Sema & Parser.
15757	struct LateParsedTemplate {
15758	CachedTokens Toks;
15759	/// The template function declaration to be late parsed.
15760	Decl *D;
15761	/// Floating-point options in the point of definition.
15762	FPOptions FPO;
15763	};
15764
15765	template <>
15766	void Sema::PragmaStack<Sema::AlignPackInfo>::Act(SourceLocation PragmaLocation,
15767	PragmaMsStackAction Action,
15768	llvm::StringRef StackSlotLabel,
15769	AlignPackInfo Value);
15770
15771	} // end namespace clang
15772
15773	#endif
15774

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