1	//===--- SemaInit.cpp - Semantic Analysis for Initializers ----------------===//
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 implements semantic analysis for initializers.
10	//
11	//===----------------------------------------------------------------------===//
12
13	#include "clang/AST/ASTContext.h"
14	#include "clang/AST/DeclObjC.h"
15	#include "clang/AST/Expr.h"
16	#include "clang/AST/ExprCXX.h"
17	#include "clang/AST/ExprObjC.h"
18	#include "clang/AST/ExprOpenMP.h"
19	#include "clang/AST/IgnoreExpr.h"
20	#include "clang/AST/TypeLoc.h"
21	#include "clang/Basic/CharInfo.h"
22	#include "clang/Basic/SourceManager.h"
23	#include "clang/Basic/Specifiers.h"
24	#include "clang/Basic/TargetInfo.h"
25	#include "clang/Sema/Designator.h"
26	#include "clang/Sema/EnterExpressionEvaluationContext.h"
27	#include "clang/Sema/Initialization.h"
28	#include "clang/Sema/Lookup.h"
29	#include "clang/Sema/Ownership.h"
30	#include "clang/Sema/SemaInternal.h"
31	#include "llvm/ADT/APInt.h"
32	#include "llvm/ADT/FoldingSet.h"
33	#include "llvm/ADT/PointerIntPair.h"
34	#include "llvm/ADT/SmallString.h"
35	#include "llvm/ADT/SmallVector.h"
36	#include "llvm/ADT/StringExtras.h"
37	#include "llvm/Support/ErrorHandling.h"
38	#include "llvm/Support/raw_ostream.h"
39
40	using namespace clang;
41
42	//===----------------------------------------------------------------------===//
43	// Sema Initialization Checking
44	//===----------------------------------------------------------------------===//
45
46	/// Check whether T is compatible with a wide character type (wchar_t,
47	/// char16_t or char32_t).
48	static bool IsWideCharCompatible(QualType T, ASTContext &Context) {
49	if (Context.typesAreCompatible(T1: Context.getWideCharType(), T2: T))
50	return true;
51	if (Context.getLangOpts().CPlusPlus || Context.getLangOpts().C11) {
52	return Context.typesAreCompatible(T1: Context.Char16Ty, T2: T) ||
53	Context.typesAreCompatible(T1: Context.Char32Ty, T2: T);
54	}
55	return false;
56	}
57
58	enum StringInitFailureKind {
59	SIF_None,
60	SIF_NarrowStringIntoWideChar,
61	SIF_WideStringIntoChar,
62	SIF_IncompatWideStringIntoWideChar,
63	SIF_UTF8StringIntoPlainChar,
64	SIF_PlainStringIntoUTF8Char,
65	SIF_Other
66	};
67
68	/// Check whether the array of type AT can be initialized by the Init
69	/// expression by means of string initialization. Returns SIF_None if so,
70	/// otherwise returns a StringInitFailureKind that describes why the
71	/// initialization would not work.
72	static StringInitFailureKind IsStringInit(Expr *Init, const ArrayType *AT,
73	ASTContext &Context) {
74	if (!isa<ConstantArrayType>(Val: AT) && !isa<IncompleteArrayType>(Val: AT))
75	return SIF_Other;
76
77	// See if this is a string literal or @encode.
78	Init = Init->IgnoreParens();
79
80	// Handle @encode, which is a narrow string.
81	if (isa<ObjCEncodeExpr>(Val: Init) && AT->getElementType()->isCharType())
82	return SIF_None;
83
84	// Otherwise we can only handle string literals.
85	StringLiteral *SL = dyn_cast<StringLiteral>(Val: Init);
86	if (!SL)
87	return SIF_Other;
88
89	const QualType ElemTy =
90	Context.getCanonicalType(T: AT->getElementType()).getUnqualifiedType();
91
92	auto IsCharOrUnsignedChar = [](const QualType &T) {
93	const BuiltinType *BT = dyn_cast<BuiltinType>(Val: T.getTypePtr());
94	return BT && BT->isCharType() && BT->getKind() != BuiltinType::SChar;
95	};
96
97	switch (SL->getKind()) {
98	case StringLiteralKind::UTF8:
99	// char8_t array can be initialized with a UTF-8 string.
100	// - C++20 [dcl.init.string] (DR)
101	// Additionally, an array of char or unsigned char may be initialized
102	// by a UTF-8 string literal.
103	if (ElemTy->isChar8Type() ||
104	(Context.getLangOpts().Char8 &&
105	IsCharOrUnsignedChar(ElemTy.getCanonicalType())))
106	return SIF_None;
107	[[fallthrough]];
108	case StringLiteralKind::Ordinary:
109	// char array can be initialized with a narrow string.
110	// Only allow char x[] = "foo"; not char x[] = L"foo";
111	if (ElemTy->isCharType())
112	return (SL->getKind() == StringLiteralKind::UTF8 &&
113	Context.getLangOpts().Char8)
114	? SIF_UTF8StringIntoPlainChar
115	: SIF_None;
116	if (ElemTy->isChar8Type())
117	return SIF_PlainStringIntoUTF8Char;
118	if (IsWideCharCompatible(T: ElemTy, Context))
119	return SIF_NarrowStringIntoWideChar;
120	return SIF_Other;
121	// C99 6.7.8p15 (with correction from DR343), or C11 6.7.9p15:
122	// "An array with element type compatible with a qualified or unqualified
123	// version of wchar_t, char16_t, or char32_t may be initialized by a wide
124	// string literal with the corresponding encoding prefix (L, u, or U,
125	// respectively), optionally enclosed in braces.
126	case StringLiteralKind::UTF16:
127	if (Context.typesAreCompatible(T1: Context.Char16Ty, T2: ElemTy))
128	return SIF_None;
129	if (ElemTy->isCharType() || ElemTy->isChar8Type())
130	return SIF_WideStringIntoChar;
131	if (IsWideCharCompatible(T: ElemTy, Context))
132	return SIF_IncompatWideStringIntoWideChar;
133	return SIF_Other;
134	case StringLiteralKind::UTF32:
135	if (Context.typesAreCompatible(T1: Context.Char32Ty, T2: ElemTy))
136	return SIF_None;
137	if (ElemTy->isCharType() || ElemTy->isChar8Type())
138	return SIF_WideStringIntoChar;
139	if (IsWideCharCompatible(T: ElemTy, Context))
140	return SIF_IncompatWideStringIntoWideChar;
141	return SIF_Other;
142	case StringLiteralKind::Wide:
143	if (Context.typesAreCompatible(T1: Context.getWideCharType(), T2: ElemTy))
144	return SIF_None;
145	if (ElemTy->isCharType() || ElemTy->isChar8Type())
146	return SIF_WideStringIntoChar;
147	if (IsWideCharCompatible(T: ElemTy, Context))
148	return SIF_IncompatWideStringIntoWideChar;
149	return SIF_Other;
150	case StringLiteralKind::Unevaluated:
151	assert(false && "Unevaluated string literal in initialization");
152	break;
153	}
154
155	llvm_unreachable("missed a StringLiteral kind?");
156	}
157
158	static StringInitFailureKind IsStringInit(Expr *init, QualType declType,
159	ASTContext &Context) {
160	const ArrayType *arrayType = Context.getAsArrayType(T: declType);
161	if (!arrayType)
162	return SIF_Other;
163	return IsStringInit(Init: init, AT: arrayType, Context);
164	}
165
166	bool Sema::IsStringInit(Expr *Init, const ArrayType *AT) {
167	return ::IsStringInit(Init, AT, Context) == SIF_None;
168	}
169
170	/// Update the type of a string literal, including any surrounding parentheses,
171	/// to match the type of the object which it is initializing.
172	static void updateStringLiteralType(Expr *E, QualType Ty) {
173	while (true) {
174	E->setType(Ty);
175	E->setValueKind(VK_PRValue);
176	if (isa<StringLiteral>(Val: E) || isa<ObjCEncodeExpr>(Val: E))
177	break;
178	E = IgnoreParensSingleStep(E);
179	}
180	}
181
182	/// Fix a compound literal initializing an array so it's correctly marked
183	/// as an rvalue.
184	static void updateGNUCompoundLiteralRValue(Expr *E) {
185	while (true) {
186	E->setValueKind(VK_PRValue);
187	if (isa<CompoundLiteralExpr>(Val: E))
188	break;
189	E = IgnoreParensSingleStep(E);
190	}
191	}
192
193	static void CheckStringInit(Expr *Str, QualType &DeclT, const ArrayType *AT,
194	Sema &S) {
195	// Get the length of the string as parsed.
196	auto *ConstantArrayTy =
197	cast<ConstantArrayType>(Str->getType()->getAsArrayTypeUnsafe());
198	uint64_t StrLength = ConstantArrayTy->getSize().getZExtValue();
199
200	if (const IncompleteArrayType *IAT = dyn_cast<IncompleteArrayType>(Val: AT)) {
201	// C99 6.7.8p14. We have an array of character type with unknown size
202	// being initialized to a string literal.
203	llvm::APInt ConstVal(32, StrLength);
204	// Return a new array type (C99 6.7.8p22).
205	DeclT = S.Context.getConstantArrayType(
206	EltTy: IAT->getElementType(), ArySize: ConstVal, SizeExpr: nullptr, ASM: ArraySizeModifier::Normal, IndexTypeQuals: 0);
207	updateStringLiteralType(E: Str, Ty: DeclT);
208	return;
209	}
210
211	const ConstantArrayType *CAT = cast<ConstantArrayType>(Val: AT);
212
213	// We have an array of character type with known size. However,
214	// the size may be smaller or larger than the string we are initializing.
215	// FIXME: Avoid truncation for 64-bit length strings.
216	if (S.getLangOpts().CPlusPlus) {
217	if (StringLiteral *SL = dyn_cast<StringLiteral>(Val: Str->IgnoreParens())) {
218	// For Pascal strings it's OK to strip off the terminating null character,
219	// so the example below is valid:
220	//
221	// unsigned char a[2] = "\pa";
222	if (SL->isPascal())
223	StrLength--;
224	}
225
226	// [dcl.init.string]p2
227	if (StrLength > CAT->getSize().getZExtValue())
228	S.Diag(Str->getBeginLoc(),
229	diag::err_initializer_string_for_char_array_too_long)
230	<< CAT->getSize().getZExtValue() << StrLength
231	<< Str->getSourceRange();
232	} else {
233	// C99 6.7.8p14.
234	if (StrLength-1 > CAT->getSize().getZExtValue())
235	S.Diag(Str->getBeginLoc(),
236	diag::ext_initializer_string_for_char_array_too_long)
237	<< Str->getSourceRange();
238	}
239
240	// Set the type to the actual size that we are initializing. If we have
241	// something like:
242	// char x[1] = "foo";
243	// then this will set the string literal's type to char[1].
244	updateStringLiteralType(E: Str, Ty: DeclT);
245	}
246
247	//===----------------------------------------------------------------------===//
248	// Semantic checking for initializer lists.
249	//===----------------------------------------------------------------------===//
250
251	namespace {
252
253	/// Semantic checking for initializer lists.
254	///
255	/// The InitListChecker class contains a set of routines that each
256	/// handle the initialization of a certain kind of entity, e.g.,
257	/// arrays, vectors, struct/union types, scalars, etc. The
258	/// InitListChecker itself performs a recursive walk of the subobject
259	/// structure of the type to be initialized, while stepping through
260	/// the initializer list one element at a time. The IList and Index
261	/// parameters to each of the Check* routines contain the active
262	/// (syntactic) initializer list and the index into that initializer
263	/// list that represents the current initializer. Each routine is
264	/// responsible for moving that Index forward as it consumes elements.
265	///
266	/// Each Check* routine also has a StructuredList/StructuredIndex
267	/// arguments, which contains the current "structured" (semantic)
268	/// initializer list and the index into that initializer list where we
269	/// are copying initializers as we map them over to the semantic
270	/// list. Once we have completed our recursive walk of the subobject
271	/// structure, we will have constructed a full semantic initializer
272	/// list.
273	///
274	/// C99 designators cause changes in the initializer list traversal,
275	/// because they make the initialization "jump" into a specific
276	/// subobject and then continue the initialization from that
277	/// point. CheckDesignatedInitializer() recursively steps into the
278	/// designated subobject and manages backing out the recursion to
279	/// initialize the subobjects after the one designated.
280	///
281	/// If an initializer list contains any designators, we build a placeholder
282	/// structured list even in 'verify only' mode, so that we can track which
283	/// elements need 'empty' initializtion.
284	class InitListChecker {
285	Sema &SemaRef;
286	bool hadError = false;
287	bool VerifyOnly; // No diagnostics.
288	bool TreatUnavailableAsInvalid; // Used only in VerifyOnly mode.
289	bool InOverloadResolution;
290	InitListExpr *FullyStructuredList = nullptr;
291	NoInitExpr *DummyExpr = nullptr;
292	SmallVectorImpl<QualType> *AggrDeductionCandidateParamTypes = nullptr;
293
294	NoInitExpr *getDummyInit() {
295	if (!DummyExpr)
296	DummyExpr = new (SemaRef.Context) NoInitExpr(SemaRef.Context.VoidTy);
297	return DummyExpr;
298	}
299
300	void CheckImplicitInitList(const InitializedEntity &Entity,
301	InitListExpr *ParentIList, QualType T,
302	unsigned &Index, InitListExpr *StructuredList,
303	unsigned &StructuredIndex);
304	void CheckExplicitInitList(const InitializedEntity &Entity,
305	InitListExpr *IList, QualType &T,
306	InitListExpr *StructuredList,
307	bool TopLevelObject = false);
308	void CheckListElementTypes(const InitializedEntity &Entity,
309	InitListExpr *IList, QualType &DeclType,
310	bool SubobjectIsDesignatorContext,
311	unsigned &Index,
312	InitListExpr *StructuredList,
313	unsigned &StructuredIndex,
314	bool TopLevelObject = false);
315	void CheckSubElementType(const InitializedEntity &Entity,
316	InitListExpr *IList, QualType ElemType,
317	unsigned &Index,
318	InitListExpr *StructuredList,
319	unsigned &StructuredIndex,
320	bool DirectlyDesignated = false);
321	void CheckComplexType(const InitializedEntity &Entity,
322	InitListExpr *IList, QualType DeclType,
323	unsigned &Index,
324	InitListExpr *StructuredList,
325	unsigned &StructuredIndex);
326	void CheckScalarType(const InitializedEntity &Entity,
327	InitListExpr *IList, QualType DeclType,
328	unsigned &Index,
329	InitListExpr *StructuredList,
330	unsigned &StructuredIndex);
331	void CheckReferenceType(const InitializedEntity &Entity,
332	InitListExpr *IList, QualType DeclType,
333	unsigned &Index,
334	InitListExpr *StructuredList,
335	unsigned &StructuredIndex);
336	void CheckVectorType(const InitializedEntity &Entity,
337	InitListExpr *IList, QualType DeclType, unsigned &Index,
338	InitListExpr *StructuredList,
339	unsigned &StructuredIndex);
340	void CheckStructUnionTypes(const InitializedEntity &Entity,
341	InitListExpr *IList, QualType DeclType,
342	CXXRecordDecl::base_class_const_range Bases,
343	RecordDecl::field_iterator Field,
344	bool SubobjectIsDesignatorContext, unsigned &Index,
345	InitListExpr *StructuredList,
346	unsigned &StructuredIndex,
347	bool TopLevelObject = false);
348	void CheckArrayType(const InitializedEntity &Entity,
349	InitListExpr *IList, QualType &DeclType,
350	llvm::APSInt elementIndex,
351	bool SubobjectIsDesignatorContext, unsigned &Index,
352	InitListExpr *StructuredList,
353	unsigned &StructuredIndex);
354	bool CheckDesignatedInitializer(const InitializedEntity &Entity,
355	InitListExpr *IList, DesignatedInitExpr *DIE,
356	unsigned DesigIdx,
357	QualType &CurrentObjectType,
358	RecordDecl::field_iterator *NextField,
359	llvm::APSInt *NextElementIndex,
360	unsigned &Index,
361	InitListExpr *StructuredList,
362	unsigned &StructuredIndex,
363	bool FinishSubobjectInit,
364	bool TopLevelObject);
365	InitListExpr *getStructuredSubobjectInit(InitListExpr *IList, unsigned Index,
366	QualType CurrentObjectType,
367	InitListExpr *StructuredList,
368	unsigned StructuredIndex,
369	SourceRange InitRange,
370	bool IsFullyOverwritten = false);
371	void UpdateStructuredListElement(InitListExpr *StructuredList,
372	unsigned &StructuredIndex,
373	Expr *expr);
374	InitListExpr *createInitListExpr(QualType CurrentObjectType,
375	SourceRange InitRange,
376	unsigned ExpectedNumInits);
377	int numArrayElements(QualType DeclType);
378	int numStructUnionElements(QualType DeclType);
379	static RecordDecl *getRecordDecl(QualType DeclType);
380
381	ExprResult PerformEmptyInit(SourceLocation Loc,
382	const InitializedEntity &Entity);
383
384	/// Diagnose that OldInit (or part thereof) has been overridden by NewInit.
385	void diagnoseInitOverride(Expr *OldInit, SourceRange NewInitRange,
386	bool UnionOverride = false,
387	bool FullyOverwritten = true) {
388	// Overriding an initializer via a designator is valid with C99 designated
389	// initializers, but ill-formed with C++20 designated initializers.
390	unsigned DiagID =
391	SemaRef.getLangOpts().CPlusPlus
392	? (UnionOverride ? diag::ext_initializer_union_overrides
393	: diag::ext_initializer_overrides)
394	: diag::warn_initializer_overrides;
395
396	if (InOverloadResolution && SemaRef.getLangOpts().CPlusPlus) {
397	// In overload resolution, we have to strictly enforce the rules, and so
398	// don't allow any overriding of prior initializers. This matters for a
399	// case such as:
400	//
401	// union U { int a, b; };
402	// struct S { int a, b; };
403	// void f(U), f(S);
404	//
405	// Here, f({.a = 1, .b = 2}) is required to call the struct overload. For
406	// consistency, we disallow all overriding of prior initializers in
407	// overload resolution, not only overriding of union members.
408	hadError = true;
409	} else if (OldInit->getType().isDestructedType() && !FullyOverwritten) {
410	// If we'll be keeping around the old initializer but overwriting part of
411	// the object it initialized, and that object is not trivially
412	// destructible, this can leak. Don't allow that, not even as an
413	// extension.
414	//
415	// FIXME: It might be reasonable to allow this in cases where the part of
416	// the initializer that we're overriding has trivial destruction.
417	DiagID = diag::err_initializer_overrides_destructed;
418	} else if (!OldInit->getSourceRange().isValid()) {
419	// We need to check on source range validity because the previous
420	// initializer does not have to be an explicit initializer. e.g.,
421	//
422	// struct P { int a, b; };
423	// struct PP { struct P p } l = { { .a = 2 }, .p.b = 3 };
424	//
425	// There is an overwrite taking place because the first braced initializer
426	// list "{ .a = 2 }" already provides value for .p.b (which is zero).
427	//
428	// Such overwrites are harmless, so we don't diagnose them. (Note that in
429	// C++, this cannot be reached unless we've already seen and diagnosed a
430	// different conformance issue, such as a mixture of designated and
431	// non-designated initializers or a multi-level designator.)
432	return;
433	}
434
435	if (!VerifyOnly) {
436	SemaRef.Diag(Loc: NewInitRange.getBegin(), DiagID)
437	<< NewInitRange << FullyOverwritten << OldInit->getType();
438	SemaRef.Diag(OldInit->getBeginLoc(), diag::note_previous_initializer)
439	<< (OldInit->HasSideEffects(SemaRef.Context) && FullyOverwritten)
440	<< OldInit->getSourceRange();
441	}
442	}
443
444	// Explanation on the "FillWithNoInit" mode:
445	//
446	// Assume we have the following definitions (Case#1):
447	// struct P { char x[6][6]; } xp = { .x[1] = "bar" };
448	// struct PP { struct P lp; } l = { .lp = xp, .lp.x[1][2] = 'f' };
449	//
450	// l.lp.x[1][0..1] should not be filled with implicit initializers because the
451	// "base" initializer "xp" will provide values for them; l.lp.x[1] will be "baf".
452	//
453	// But if we have (Case#2):
454	// struct PP l = { .lp = xp, .lp.x[1] = { [2] = 'f' } };
455	//
456	// l.lp.x[1][0..1] are implicitly initialized and do not use values from the
457	// "base" initializer; l.lp.x[1] will be "\0\0f\0\0\0".
458	//
459	// To distinguish Case#1 from Case#2, and also to avoid leaving many "holes"
460	// in the InitListExpr, the "holes" in Case#1 are filled not with empty
461	// initializers but with special "NoInitExpr" place holders, which tells the
462	// CodeGen not to generate any initializers for these parts.
463	void FillInEmptyInitForBase(unsigned Init, const CXXBaseSpecifier &Base,
464	const InitializedEntity &ParentEntity,
465	InitListExpr *ILE, bool &RequiresSecondPass,
466	bool FillWithNoInit);
467	void FillInEmptyInitForField(unsigned Init, FieldDecl *Field,
468	const InitializedEntity &ParentEntity,
469	InitListExpr *ILE, bool &RequiresSecondPass,
470	bool FillWithNoInit = false);
471	void FillInEmptyInitializations(const InitializedEntity &Entity,
472	InitListExpr *ILE, bool &RequiresSecondPass,
473	InitListExpr *OuterILE, unsigned OuterIndex,
474	bool FillWithNoInit = false);
475	bool CheckFlexibleArrayInit(const InitializedEntity &Entity,
476	Expr *InitExpr, FieldDecl *Field,
477	bool TopLevelObject);
478	void CheckEmptyInitializable(const InitializedEntity &Entity,
479	SourceLocation Loc);
480
481	public:
482	InitListChecker(
483	Sema &S, const InitializedEntity &Entity, InitListExpr *IL, QualType &T,
484	bool VerifyOnly, bool TreatUnavailableAsInvalid,
485	bool InOverloadResolution = false,
486	SmallVectorImpl<QualType> *AggrDeductionCandidateParamTypes = nullptr);
487	InitListChecker(Sema &S, const InitializedEntity &Entity, InitListExpr *IL,
488	QualType &T,
489	SmallVectorImpl<QualType> &AggrDeductionCandidateParamTypes)
490	: InitListChecker(S, Entity, IL, T, /*VerifyOnly=*/true,
491	/*TreatUnavailableAsInvalid=*/false,
492	/*InOverloadResolution=*/false,
493	&AggrDeductionCandidateParamTypes){};
494
495	bool HadError() { return hadError; }
496
497	// Retrieves the fully-structured initializer list used for
498	// semantic analysis and code generation.
499	InitListExpr *getFullyStructuredList() const { return FullyStructuredList; }
500	};
501
502	} // end anonymous namespace
503
504	ExprResult InitListChecker::PerformEmptyInit(SourceLocation Loc,
505	const InitializedEntity &Entity) {
506	InitializationKind Kind = InitializationKind::CreateValue(InitLoc: Loc, LParenLoc: Loc, RParenLoc: Loc,
507	isImplicit: true);
508	MultiExprArg SubInit;
509	Expr *InitExpr;
510	InitListExpr DummyInitList(SemaRef.Context, Loc, std::nullopt, Loc);
511
512	// C++ [dcl.init.aggr]p7:
513	// If there are fewer initializer-clauses in the list than there are
514	// members in the aggregate, then each member not explicitly initialized
515	// ...
516	bool EmptyInitList = SemaRef.getLangOpts().CPlusPlus11 &&
517	Entity.getType()->getBaseElementTypeUnsafe()->isRecordType();
518	if (EmptyInitList) {
519	// C++1y / DR1070:
520	// shall be initialized [...] from an empty initializer list.
521	//
522	// We apply the resolution of this DR to C++11 but not C++98, since C++98
523	// does not have useful semantics for initialization from an init list.
524	// We treat this as copy-initialization, because aggregate initialization
525	// always performs copy-initialization on its elements.
526	//
527	// Only do this if we're initializing a class type, to avoid filling in
528	// the initializer list where possible.
529	InitExpr = VerifyOnly
530	? &DummyInitList
531	: new (SemaRef.Context)
532	InitListExpr(SemaRef.Context, Loc, std::nullopt, Loc);
533	InitExpr->setType(SemaRef.Context.VoidTy);
534	SubInit = InitExpr;
535	Kind = InitializationKind::CreateCopy(InitLoc: Loc, EqualLoc: Loc);
536	} else {
537	// C++03:
538	// shall be value-initialized.
539	}
540
541	InitializationSequence InitSeq(SemaRef, Entity, Kind, SubInit);
542	// libstdc++4.6 marks the vector default constructor as explicit in
543	// _GLIBCXX_DEBUG mode, so recover using the C++03 logic in that case.
544	// stlport does so too. Look for std::__debug for libstdc++, and for
545	// std:: for stlport. This is effectively a compiler-side implementation of
546	// LWG2193.
547	if (!InitSeq && EmptyInitList && InitSeq.getFailureKind() ==
548	InitializationSequence::FK_ExplicitConstructor) {
549	OverloadCandidateSet::iterator Best;
550	OverloadingResult O =
551	InitSeq.getFailedCandidateSet()
552	.BestViableFunction(S&: SemaRef, Loc: Kind.getLocation(), Best);
553	(void)O;
554	assert(O == OR_Success && "Inconsistent overload resolution");
555	CXXConstructorDecl *CtorDecl = cast<CXXConstructorDecl>(Val: Best->Function);
556	CXXRecordDecl *R = CtorDecl->getParent();
557
558	if (CtorDecl->getMinRequiredArguments() == 0 &&
559	CtorDecl->isExplicit() && R->getDeclName() &&
560	SemaRef.SourceMgr.isInSystemHeader(Loc: CtorDecl->getLocation())) {
561	bool IsInStd = false;
562	for (NamespaceDecl *ND = dyn_cast<NamespaceDecl>(R->getDeclContext());
563	ND && !IsInStd; ND = dyn_cast<NamespaceDecl>(ND->getParent())) {
564	if (SemaRef.getStdNamespace()->InEnclosingNamespaceSetOf(ND))
565	IsInStd = true;
566	}
567
568	if (IsInStd && llvm::StringSwitch<bool>(R->getName())
569	.Cases(S0: "basic_string", S1: "deque", S2: "forward_list", Value: true)
570	.Cases(S0: "list", S1: "map", S2: "multimap", S3: "multiset", Value: true)
571	.Cases(S0: "priority_queue", S1: "queue", S2: "set", S3: "stack", Value: true)
572	.Cases(S0: "unordered_map", S1: "unordered_set", S2: "vector", Value: true)
573	.Default(Value: false)) {
574	InitSeq.InitializeFrom(
575	S&: SemaRef, Entity,
576	Kind: InitializationKind::CreateValue(InitLoc: Loc, LParenLoc: Loc, RParenLoc: Loc, isImplicit: true),
577	Args: MultiExprArg(), /*TopLevelOfInitList=*/false,
578	TreatUnavailableAsInvalid);
579	// Emit a warning for this. System header warnings aren't shown
580	// by default, but people working on system headers should see it.
581	if (!VerifyOnly) {
582	SemaRef.Diag(CtorDecl->getLocation(),
583	diag::warn_invalid_initializer_from_system_header);
584	if (Entity.getKind() == InitializedEntity::EK_Member)
585	SemaRef.Diag(Entity.getDecl()->getLocation(),
586	diag::note_used_in_initialization_here);
587	else if (Entity.getKind() == InitializedEntity::EK_ArrayElement)
588	SemaRef.Diag(Loc, diag::note_used_in_initialization_here);
589	}
590	}
591	}
592	}
593	if (!InitSeq) {
594	if (!VerifyOnly) {
595	InitSeq.Diagnose(S&: SemaRef, Entity, Kind, Args: SubInit);
596	if (Entity.getKind() == InitializedEntity::EK_Member)
597	SemaRef.Diag(Entity.getDecl()->getLocation(),
598	diag::note_in_omitted_aggregate_initializer)
599	<< /*field*/1 << Entity.getDecl();
600	else if (Entity.getKind() == InitializedEntity::EK_ArrayElement) {
601	bool IsTrailingArrayNewMember =
602	Entity.getParent() &&
603	Entity.getParent()->isVariableLengthArrayNew();
604	SemaRef.Diag(Loc, diag::note_in_omitted_aggregate_initializer)
605	<< (IsTrailingArrayNewMember ? 2 : /*array element*/0)
606	<< Entity.getElementIndex();
607	}
608	}
609	hadError = true;
610	return ExprError();
611	}
612
613	return VerifyOnly ? ExprResult()
614	: InitSeq.Perform(S&: SemaRef, Entity, Kind, Args: SubInit);
615	}
616
617	void InitListChecker::CheckEmptyInitializable(const InitializedEntity &Entity,
618	SourceLocation Loc) {
619	// If we're building a fully-structured list, we'll check this at the end
620	// once we know which elements are actually initialized. Otherwise, we know
621	// that there are no designators so we can just check now.
622	if (FullyStructuredList)
623	return;
624	PerformEmptyInit(Loc, Entity);
625	}
626
627	void InitListChecker::FillInEmptyInitForBase(
628	unsigned Init, const CXXBaseSpecifier &Base,
629	const InitializedEntity &ParentEntity, InitListExpr *ILE,
630	bool &RequiresSecondPass, bool FillWithNoInit) {
631	InitializedEntity BaseEntity = InitializedEntity::InitializeBase(
632	Context&: SemaRef.Context, Base: &Base, IsInheritedVirtualBase: false, Parent: &ParentEntity);
633
634	if (Init >= ILE->getNumInits() || !ILE->getInit(Init)) {
635	ExprResult BaseInit = FillWithNoInit
636	? new (SemaRef.Context) NoInitExpr(Base.getType())
637	: PerformEmptyInit(Loc: ILE->getEndLoc(), Entity: BaseEntity);
638	if (BaseInit.isInvalid()) {
639	hadError = true;
640	return;
641	}
642
643	if (!VerifyOnly) {
644	assert(Init < ILE->getNumInits() && "should have been expanded");
645	ILE->setInit(Init, expr: BaseInit.getAs<Expr>());
646	}
647	} else if (InitListExpr *InnerILE =
648	dyn_cast<InitListExpr>(Val: ILE->getInit(Init))) {
649	FillInEmptyInitializations(Entity: BaseEntity, ILE: InnerILE, RequiresSecondPass,
650	OuterILE: ILE, OuterIndex: Init, FillWithNoInit);
651	} else if (DesignatedInitUpdateExpr *InnerDIUE =
652	dyn_cast<DesignatedInitUpdateExpr>(Val: ILE->getInit(Init))) {
653	FillInEmptyInitializations(Entity: BaseEntity, ILE: InnerDIUE->getUpdater(),
654	RequiresSecondPass, OuterILE: ILE, OuterIndex: Init,
655	/*FillWithNoInit =*/true);
656	}
657	}
658
659	void InitListChecker::FillInEmptyInitForField(unsigned Init, FieldDecl *Field,
660	const InitializedEntity &ParentEntity,
661	InitListExpr *ILE,
662	bool &RequiresSecondPass,
663	bool FillWithNoInit) {
664	SourceLocation Loc = ILE->getEndLoc();
665	unsigned NumInits = ILE->getNumInits();
666	InitializedEntity MemberEntity
667	= InitializedEntity::InitializeMember(Member: Field, Parent: &ParentEntity);
668
669	if (Init >= NumInits || !ILE->getInit(Init)) {
670	if (const RecordType *RType = ILE->getType()->getAs<RecordType>())
671	if (!RType->getDecl()->isUnion())
672	assert((Init < NumInits || VerifyOnly) &&
673	"This ILE should have been expanded");
674
675	if (FillWithNoInit) {
676	assert(!VerifyOnly && "should not fill with no-init in verify-only mode");
677	Expr *Filler = new (SemaRef.Context) NoInitExpr(Field->getType());
678	if (Init < NumInits)
679	ILE->setInit(Init, expr: Filler);
680	else
681	ILE->updateInit(C: SemaRef.Context, Init, expr: Filler);
682	return;
683	}
684	// C++1y [dcl.init.aggr]p7:
685	// If there are fewer initializer-clauses in the list than there are
686	// members in the aggregate, then each member not explicitly initialized
687	// shall be initialized from its brace-or-equal-initializer [...]
688	if (Field->hasInClassInitializer()) {
689	if (VerifyOnly)
690	return;
691
692	ExprResult DIE = SemaRef.BuildCXXDefaultInitExpr(Loc, Field);
693	if (DIE.isInvalid()) {
694	hadError = true;
695	return;
696	}
697	SemaRef.checkInitializerLifetime(Entity: MemberEntity, Init: DIE.get());
698	if (Init < NumInits)
699	ILE->setInit(Init, expr: DIE.get());
700	else {
701	ILE->updateInit(C: SemaRef.Context, Init, expr: DIE.get());
702	RequiresSecondPass = true;
703	}
704	return;
705	}
706
707	if (Field->getType()->isReferenceType()) {
708	if (!VerifyOnly) {
709	// C++ [dcl.init.aggr]p9:
710	// If an incomplete or empty initializer-list leaves a
711	// member of reference type uninitialized, the program is
712	// ill-formed.
713	SemaRef.Diag(Loc, diag::err_init_reference_member_uninitialized)
714	<< Field->getType()
715	<< (ILE->isSyntacticForm() ? ILE : ILE->getSyntacticForm())
716	->getSourceRange();
717	SemaRef.Diag(Field->getLocation(), diag::note_uninit_reference_member);
718	}
719	hadError = true;
720	return;
721	}
722
723	ExprResult MemberInit = PerformEmptyInit(Loc, Entity: MemberEntity);
724	if (MemberInit.isInvalid()) {
725	hadError = true;
726	return;
727	}
728
729	if (hadError || VerifyOnly) {
730	// Do nothing
731	} else if (Init < NumInits) {
732	ILE->setInit(Init, expr: MemberInit.getAs<Expr>());
733	} else if (!isa<ImplicitValueInitExpr>(Val: MemberInit.get())) {
734	// Empty initialization requires a constructor call, so
735	// extend the initializer list to include the constructor
736	// call and make a note that we'll need to take another pass
737	// through the initializer list.
738	ILE->updateInit(C: SemaRef.Context, Init, expr: MemberInit.getAs<Expr>());
739	RequiresSecondPass = true;
740	}
741	} else if (InitListExpr *InnerILE
742	= dyn_cast<InitListExpr>(Val: ILE->getInit(Init))) {
743	FillInEmptyInitializations(Entity: MemberEntity, ILE: InnerILE,
744	RequiresSecondPass, OuterILE: ILE, OuterIndex: Init, FillWithNoInit);
745	} else if (DesignatedInitUpdateExpr *InnerDIUE =
746	dyn_cast<DesignatedInitUpdateExpr>(Val: ILE->getInit(Init))) {
747	FillInEmptyInitializations(Entity: MemberEntity, ILE: InnerDIUE->getUpdater(),
748	RequiresSecondPass, OuterILE: ILE, OuterIndex: Init,
749	/*FillWithNoInit =*/true);
750	}
751	}
752
753	/// Recursively replaces NULL values within the given initializer list
754	/// with expressions that perform value-initialization of the
755	/// appropriate type, and finish off the InitListExpr formation.
756	void
757	InitListChecker::FillInEmptyInitializations(const InitializedEntity &Entity,
758	InitListExpr *ILE,
759	bool &RequiresSecondPass,
760	InitListExpr *OuterILE,
761	unsigned OuterIndex,
762	bool FillWithNoInit) {
763	assert((ILE->getType() != SemaRef.Context.VoidTy) &&
764	"Should not have void type");
765
766	// We don't need to do any checks when just filling NoInitExprs; that can't
767	// fail.
768	if (FillWithNoInit && VerifyOnly)
769	return;
770
771	// If this is a nested initializer list, we might have changed its contents
772	// (and therefore some of its properties, such as instantiation-dependence)
773	// while filling it in. Inform the outer initializer list so that its state
774	// can be updated to match.
775	// FIXME: We should fully build the inner initializers before constructing
776	// the outer InitListExpr instead of mutating AST nodes after they have
777	// been used as subexpressions of other nodes.
778	struct UpdateOuterILEWithUpdatedInit {
779	InitListExpr *Outer;
780	unsigned OuterIndex;
781	~UpdateOuterILEWithUpdatedInit() {
782	if (Outer)
783	Outer->setInit(Init: OuterIndex, expr: Outer->getInit(Init: OuterIndex));
784	}
785	} UpdateOuterRAII = {.Outer: OuterILE, .OuterIndex: OuterIndex};
786
787	// A transparent ILE is not performing aggregate initialization and should
788	// not be filled in.
789	if (ILE->isTransparent())
790	return;
791
792	if (const RecordType *RType = ILE->getType()->getAs<RecordType>()) {
793	const RecordDecl *RDecl = RType->getDecl();
794	if (RDecl->isUnion() && ILE->getInitializedFieldInUnion())
795	FillInEmptyInitForField(Init: 0, Field: ILE->getInitializedFieldInUnion(),
796	ParentEntity: Entity, ILE, RequiresSecondPass, FillWithNoInit);
797	else if (RDecl->isUnion() && isa<CXXRecordDecl>(Val: RDecl) &&
798	cast<CXXRecordDecl>(Val: RDecl)->hasInClassInitializer()) {
799	for (auto *Field : RDecl->fields()) {
800	if (Field->hasInClassInitializer()) {
801	FillInEmptyInitForField(0, Field, Entity, ILE, RequiresSecondPass,
802	FillWithNoInit);
803	break;
804	}
805	}
806	} else {
807	// The fields beyond ILE->getNumInits() are default initialized, so in
808	// order to leave them uninitialized, the ILE is expanded and the extra
809	// fields are then filled with NoInitExpr.
810	unsigned NumElems = numStructUnionElements(DeclType: ILE->getType());
811	if (!RDecl->isUnion() && RDecl->hasFlexibleArrayMember())
812	++NumElems;
813	if (!VerifyOnly && ILE->getNumInits() < NumElems)
814	ILE->resizeInits(Context: SemaRef.Context, NumInits: NumElems);
815
816	unsigned Init = 0;
817
818	if (auto *CXXRD = dyn_cast<CXXRecordDecl>(RDecl)) {
819	for (auto &Base : CXXRD->bases()) {
820	if (hadError)
821	return;
822
823	FillInEmptyInitForBase(Init, Base, Entity, ILE, RequiresSecondPass,
824	FillWithNoInit);
825	++Init;
826	}
827	}
828
829	for (auto *Field : RDecl->fields()) {
830	if (Field->isUnnamedBitfield())
831	continue;
832
833	if (hadError)
834	return;
835
836	FillInEmptyInitForField(Init, Field, Entity, ILE, RequiresSecondPass,
837	FillWithNoInit);
838	if (hadError)
839	return;
840
841	++Init;
842
843	// Only look at the first initialization of a union.
844	if (RDecl->isUnion())
845	break;
846	}
847	}
848
849	return;
850	}
851
852	QualType ElementType;
853
854	InitializedEntity ElementEntity = Entity;
855	unsigned NumInits = ILE->getNumInits();
856	unsigned NumElements = NumInits;
857	if (const ArrayType *AType = SemaRef.Context.getAsArrayType(T: ILE->getType())) {
858	ElementType = AType->getElementType();
859	if (const auto *CAType = dyn_cast<ConstantArrayType>(AType))
860	NumElements = CAType->getSize().getZExtValue();
861	// For an array new with an unknown bound, ask for one additional element
862	// in order to populate the array filler.
863	if (Entity.isVariableLengthArrayNew())
864	++NumElements;
865	ElementEntity = InitializedEntity::InitializeElement(Context&: SemaRef.Context,
866	Index: 0, Parent: Entity);
867	} else if (const VectorType *VType = ILE->getType()->getAs<VectorType>()) {
868	ElementType = VType->getElementType();
869	NumElements = VType->getNumElements();
870	ElementEntity = InitializedEntity::InitializeElement(Context&: SemaRef.Context,
871	Index: 0, Parent: Entity);
872	} else
873	ElementType = ILE->getType();
874
875	bool SkipEmptyInitChecks = false;
876	for (unsigned Init = 0; Init != NumElements; ++Init) {
877	if (hadError)
878	return;
879
880	if (ElementEntity.getKind() == InitializedEntity::EK_ArrayElement ||
881	ElementEntity.getKind() == InitializedEntity::EK_VectorElement)
882	ElementEntity.setElementIndex(Init);
883
884	if (Init >= NumInits && (ILE->hasArrayFiller() || SkipEmptyInitChecks))
885	return;
886
887	Expr *InitExpr = (Init < NumInits ? ILE->getInit(Init) : nullptr);
888	if (!InitExpr && Init < NumInits && ILE->hasArrayFiller())
889	ILE->setInit(Init, expr: ILE->getArrayFiller());
890	else if (!InitExpr && !ILE->hasArrayFiller()) {
891	// In VerifyOnly mode, there's no point performing empty initialization
892	// more than once.
893	if (SkipEmptyInitChecks)
894	continue;
895
896	Expr *Filler = nullptr;
897
898	if (FillWithNoInit)
899	Filler = new (SemaRef.Context) NoInitExpr(ElementType);
900	else {
901	ExprResult ElementInit =
902	PerformEmptyInit(Loc: ILE->getEndLoc(), Entity: ElementEntity);
903	if (ElementInit.isInvalid()) {
904	hadError = true;
905	return;
906	}
907
908	Filler = ElementInit.getAs<Expr>();
909	}
910
911	if (hadError) {
912	// Do nothing
913	} else if (VerifyOnly) {
914	SkipEmptyInitChecks = true;
915	} else if (Init < NumInits) {
916	// For arrays, just set the expression used for value-initialization
917	// of the "holes" in the array.
918	if (ElementEntity.getKind() == InitializedEntity::EK_ArrayElement)
919	ILE->setArrayFiller(Filler);
920	else
921	ILE->setInit(Init, expr: Filler);
922	} else {
923	// For arrays, just set the expression used for value-initialization
924	// of the rest of elements and exit.
925	if (ElementEntity.getKind() == InitializedEntity::EK_ArrayElement) {
926	ILE->setArrayFiller(Filler);
927	return;
928	}
929
930	if (!isa<ImplicitValueInitExpr>(Val: Filler) && !isa<NoInitExpr>(Val: Filler)) {
931	// Empty initialization requires a constructor call, so
932	// extend the initializer list to include the constructor
933	// call and make a note that we'll need to take another pass
934	// through the initializer list.
935	ILE->updateInit(C: SemaRef.Context, Init, expr: Filler);
936	RequiresSecondPass = true;
937	}
938	}
939	} else if (InitListExpr *InnerILE
940	= dyn_cast_or_null<InitListExpr>(Val: InitExpr)) {
941	FillInEmptyInitializations(Entity: ElementEntity, ILE: InnerILE, RequiresSecondPass,
942	OuterILE: ILE, OuterIndex: Init, FillWithNoInit);
943	} else if (DesignatedInitUpdateExpr *InnerDIUE =
944	dyn_cast_or_null<DesignatedInitUpdateExpr>(Val: InitExpr)) {
945	FillInEmptyInitializations(Entity: ElementEntity, ILE: InnerDIUE->getUpdater(),
946	RequiresSecondPass, OuterILE: ILE, OuterIndex: Init,
947	/*FillWithNoInit =*/true);
948	}
949	}
950	}
951
952	static bool hasAnyDesignatedInits(const InitListExpr *IL) {
953	for (const Stmt *Init : *IL)
954	if (isa_and_nonnull<DesignatedInitExpr>(Val: Init))
955	return true;
956	return false;
957	}
958
959	InitListChecker::InitListChecker(
960	Sema &S, const InitializedEntity &Entity, InitListExpr *IL, QualType &T,
961	bool VerifyOnly, bool TreatUnavailableAsInvalid, bool InOverloadResolution,
962	SmallVectorImpl<QualType> *AggrDeductionCandidateParamTypes)
963	: SemaRef(S), VerifyOnly(VerifyOnly),
964	TreatUnavailableAsInvalid(TreatUnavailableAsInvalid),
965	InOverloadResolution(InOverloadResolution),
966	AggrDeductionCandidateParamTypes(AggrDeductionCandidateParamTypes) {
967	if (!VerifyOnly || hasAnyDesignatedInits(IL)) {
968	FullyStructuredList =
969	createInitListExpr(CurrentObjectType: T, InitRange: IL->getSourceRange(), ExpectedNumInits: IL->getNumInits());
970
971	// FIXME: Check that IL isn't already the semantic form of some other
972	// InitListExpr. If it is, we'd create a broken AST.
973	if (!VerifyOnly)
974	FullyStructuredList->setSyntacticForm(IL);
975	}
976
977	CheckExplicitInitList(Entity, IList: IL, T, StructuredList: FullyStructuredList,
978	/*TopLevelObject=*/true);
979
980	if (!hadError && !AggrDeductionCandidateParamTypes && FullyStructuredList) {
981	bool RequiresSecondPass = false;
982	FillInEmptyInitializations(Entity, ILE: FullyStructuredList, RequiresSecondPass,
983	/*OuterILE=*/nullptr, /*OuterIndex=*/0);
984	if (RequiresSecondPass && !hadError)
985	FillInEmptyInitializations(Entity, ILE: FullyStructuredList,
986	RequiresSecondPass, OuterILE: nullptr, OuterIndex: 0);
987	}
988	if (hadError && FullyStructuredList)
989	FullyStructuredList->markError();
990	}
991
992	int InitListChecker::numArrayElements(QualType DeclType) {
993	// FIXME: use a proper constant
994	int maxElements = 0x7FFFFFFF;
995	if (const ConstantArrayType *CAT =
996	SemaRef.Context.getAsConstantArrayType(T: DeclType)) {
997	maxElements = static_cast<int>(CAT->getSize().getZExtValue());
998	}
999	return maxElements;
1000	}
1001
1002	int InitListChecker::numStructUnionElements(QualType DeclType) {
1003	RecordDecl *structDecl = DeclType->castAs<RecordType>()->getDecl();
1004	int InitializableMembers = 0;
1005	if (auto *CXXRD = dyn_cast<CXXRecordDecl>(Val: structDecl))
1006	InitializableMembers += CXXRD->getNumBases();
1007	for (const auto *Field : structDecl->fields())
1008	if (!Field->isUnnamedBitfield())
1009	++InitializableMembers;
1010
1011	if (structDecl->isUnion())
1012	return std::min(a: InitializableMembers, b: 1);
1013	return InitializableMembers - structDecl->hasFlexibleArrayMember();
1014	}
1015
1016	RecordDecl *InitListChecker::getRecordDecl(QualType DeclType) {
1017	if (const auto *RT = DeclType->getAs<RecordType>())
1018	return RT->getDecl();
1019	if (const auto *Inject = DeclType->getAs<InjectedClassNameType>())
1020	return Inject->getDecl();
1021	return nullptr;
1022	}
1023
1024	/// Determine whether Entity is an entity for which it is idiomatic to elide
1025	/// the braces in aggregate initialization.
1026	static bool isIdiomaticBraceElisionEntity(const InitializedEntity &Entity) {
1027	// Recursive initialization of the one and only field within an aggregate
1028	// class is considered idiomatic. This case arises in particular for
1029	// initialization of std::array, where the C++ standard suggests the idiom of
1030	//
1031	// std::array<T, N> arr = {1, 2, 3};
1032	//
1033	// (where std::array is an aggregate struct containing a single array field.
1034
1035	if (!Entity.getParent())
1036	return false;
1037
1038	// Allows elide brace initialization for aggregates with empty base.
1039	if (Entity.getKind() == InitializedEntity::EK_Base) {
1040	auto *ParentRD =
1041	Entity.getParent()->getType()->castAs<RecordType>()->getDecl();
1042	CXXRecordDecl *CXXRD = cast<CXXRecordDecl>(Val: ParentRD);
1043	return CXXRD->getNumBases() == 1 && CXXRD->field_empty();
1044	}
1045
1046	// Allow brace elision if the only subobject is a field.
1047	if (Entity.getKind() == InitializedEntity::EK_Member) {
1048	auto *ParentRD =
1049	Entity.getParent()->getType()->castAs<RecordType>()->getDecl();
1050	if (CXXRecordDecl *CXXRD = dyn_cast<CXXRecordDecl>(Val: ParentRD)) {
1051	if (CXXRD->getNumBases()) {
1052	return false;
1053	}
1054	}
1055	auto FieldIt = ParentRD->field_begin();
1056	assert(FieldIt != ParentRD->field_end() &&
1057	"no fields but have initializer for member?");
1058	return ++FieldIt == ParentRD->field_end();
1059	}
1060
1061	return false;
1062	}
1063
1064	/// Check whether the range of the initializer \p ParentIList from element
1065	/// \p Index onwards can be used to initialize an object of type \p T. Update
1066	/// \p Index to indicate how many elements of the list were consumed.
1067	///
1068	/// This also fills in \p StructuredList, from element \p StructuredIndex
1069	/// onwards, with the fully-braced, desugared form of the initialization.
1070	void InitListChecker::CheckImplicitInitList(const InitializedEntity &Entity,
1071	InitListExpr *ParentIList,
1072	QualType T, unsigned &Index,
1073	InitListExpr *StructuredList,
1074	unsigned &StructuredIndex) {
1075	int maxElements = 0;
1076
1077	if (T->isArrayType())
1078	maxElements = numArrayElements(DeclType: T);
1079	else if (T->isRecordType())
1080	maxElements = numStructUnionElements(DeclType: T);
1081	else if (T->isVectorType())
1082	maxElements = T->castAs<VectorType>()->getNumElements();
1083	else
1084	llvm_unreachable("CheckImplicitInitList(): Illegal type");
1085
1086	if (maxElements == 0) {
1087	if (!VerifyOnly)
1088	SemaRef.Diag(ParentIList->getInit(Index)->getBeginLoc(),
1089	diag::err_implicit_empty_initializer);
1090	++Index;
1091	hadError = true;
1092	return;
1093	}
1094
1095	// Build a structured initializer list corresponding to this subobject.
1096	InitListExpr *StructuredSubobjectInitList = getStructuredSubobjectInit(
1097	IList: ParentIList, Index, CurrentObjectType: T, StructuredList, StructuredIndex,
1098	InitRange: SourceRange(ParentIList->getInit(Init: Index)->getBeginLoc(),
1099	ParentIList->getSourceRange().getEnd()));
1100	unsigned StructuredSubobjectInitIndex = 0;
1101
1102	// Check the element types and build the structural subobject.
1103	unsigned StartIndex = Index;
1104	CheckListElementTypes(Entity, IList: ParentIList, DeclType&: T,
1105	/*SubobjectIsDesignatorContext=*/false, Index,
1106	StructuredList: StructuredSubobjectInitList,
1107	StructuredIndex&: StructuredSubobjectInitIndex);
1108
1109	if (StructuredSubobjectInitList) {
1110	StructuredSubobjectInitList->setType(T);
1111
1112	unsigned EndIndex = (Index == StartIndex? StartIndex : Index - 1);
1113	// Update the structured sub-object initializer so that it's ending
1114	// range corresponds with the end of the last initializer it used.
1115	if (EndIndex < ParentIList->getNumInits() &&
1116	ParentIList->getInit(Init: EndIndex)) {
1117	SourceLocation EndLoc
1118	= ParentIList->getInit(Init: EndIndex)->getSourceRange().getEnd();
1119	StructuredSubobjectInitList->setRBraceLoc(EndLoc);
1120	}
1121
1122	// Complain about missing braces.
1123	if (!VerifyOnly && (T->isArrayType() || T->isRecordType()) &&
1124	!ParentIList->isIdiomaticZeroInitializer(LangOpts: SemaRef.getLangOpts()) &&
1125	!isIdiomaticBraceElisionEntity(Entity)) {
1126	SemaRef.Diag(StructuredSubobjectInitList->getBeginLoc(),
1127	diag::warn_missing_braces)
1128	<< StructuredSubobjectInitList->getSourceRange()
1129	<< FixItHint::CreateInsertion(
1130	StructuredSubobjectInitList->getBeginLoc(), "{")
1131	<< FixItHint::CreateInsertion(
1132	SemaRef.getLocForEndOfToken(
1133	StructuredSubobjectInitList->getEndLoc()),
1134	"}");
1135	}
1136
1137	// Warn if this type won't be an aggregate in future versions of C++.
1138	auto *CXXRD = T->getAsCXXRecordDecl();
1139	if (!VerifyOnly && CXXRD && CXXRD->hasUserDeclaredConstructor()) {
1140	SemaRef.Diag(StructuredSubobjectInitList->getBeginLoc(),
1141	diag::warn_cxx20_compat_aggregate_init_with_ctors)
1142	<< StructuredSubobjectInitList->getSourceRange() << T;
1143	}
1144	}
1145	}
1146
1147	/// Warn that \p Entity was of scalar type and was initialized by a
1148	/// single-element braced initializer list.
1149	static void warnBracedScalarInit(Sema &S, const InitializedEntity &Entity,
1150	SourceRange Braces) {
1151	// Don't warn during template instantiation. If the initialization was
1152	// non-dependent, we warned during the initial parse; otherwise, the
1153	// type might not be scalar in some uses of the template.
1154	if (S.inTemplateInstantiation())
1155	return;
1156
1157	unsigned DiagID = 0;
1158
1159	switch (Entity.getKind()) {
1160	case InitializedEntity::EK_VectorElement:
1161	case InitializedEntity::EK_ComplexElement:
1162	case InitializedEntity::EK_ArrayElement:
1163	case InitializedEntity::EK_Parameter:
1164	case InitializedEntity::EK_Parameter_CF_Audited:
1165	case InitializedEntity::EK_TemplateParameter:
1166	case InitializedEntity::EK_Result:
1167	case InitializedEntity::EK_ParenAggInitMember:
1168	// Extra braces here are suspicious.
1169	DiagID = diag::warn_braces_around_init;
1170	break;
1171
1172	case InitializedEntity::EK_Member:
1173	// Warn on aggregate initialization but not on ctor init list or
1174	// default member initializer.
1175	if (Entity.getParent())
1176	DiagID = diag::warn_braces_around_init;
1177	break;
1178
1179	case InitializedEntity::EK_Variable:
1180	case InitializedEntity::EK_LambdaCapture:
1181	// No warning, might be direct-list-initialization.
1182	// FIXME: Should we warn for copy-list-initialization in these cases?
1183	break;
1184
1185	case InitializedEntity::EK_New:
1186	case InitializedEntity::EK_Temporary:
1187	case InitializedEntity::EK_CompoundLiteralInit:
1188	// No warning, braces are part of the syntax of the underlying construct.
1189	break;
1190
1191	case InitializedEntity::EK_RelatedResult:
1192	// No warning, we already warned when initializing the result.
1193	break;
1194
1195	case InitializedEntity::EK_Exception:
1196	case InitializedEntity::EK_Base:
1197	case InitializedEntity::EK_Delegating:
1198	case InitializedEntity::EK_BlockElement:
1199	case InitializedEntity::EK_LambdaToBlockConversionBlockElement:
1200	case InitializedEntity::EK_Binding:
1201	case InitializedEntity::EK_StmtExprResult:
1202	llvm_unreachable("unexpected braced scalar init");
1203	}
1204
1205	if (DiagID) {
1206	S.Diag(Loc: Braces.getBegin(), DiagID)
1207	<< Entity.getType()->isSizelessBuiltinType() << Braces
1208	<< FixItHint::CreateRemoval(RemoveRange: Braces.getBegin())
1209	<< FixItHint::CreateRemoval(RemoveRange: Braces.getEnd());
1210	}
1211	}
1212
1213	/// Check whether the initializer \p IList (that was written with explicit
1214	/// braces) can be used to initialize an object of type \p T.
1215	///
1216	/// This also fills in \p StructuredList with the fully-braced, desugared
1217	/// form of the initialization.
1218	void InitListChecker::CheckExplicitInitList(const InitializedEntity &Entity,
1219	InitListExpr *IList, QualType &T,
1220	InitListExpr *StructuredList,
1221	bool TopLevelObject) {
1222	unsigned Index = 0, StructuredIndex = 0;
1223	CheckListElementTypes(Entity, IList, DeclType&: T, /*SubobjectIsDesignatorContext=*/true,
1224	Index, StructuredList, StructuredIndex, TopLevelObject);
1225	if (StructuredList) {
1226	QualType ExprTy = T;
1227	if (!ExprTy->isArrayType())
1228	ExprTy = ExprTy.getNonLValueExprType(Context: SemaRef.Context);
1229	if (!VerifyOnly)
1230	IList->setType(ExprTy);
1231	StructuredList->setType(ExprTy);
1232	}
1233	if (hadError)
1234	return;
1235
1236	// Don't complain for incomplete types, since we'll get an error elsewhere.
1237	if (Index < IList->getNumInits() && !T->isIncompleteType()) {
1238	// We have leftover initializers
1239	bool ExtraInitsIsError = SemaRef.getLangOpts().CPlusPlus ||
1240	(SemaRef.getLangOpts().OpenCL && T->isVectorType());
1241	hadError = ExtraInitsIsError;
1242	if (VerifyOnly) {
1243	return;
1244	} else if (StructuredIndex == 1 &&
1245	IsStringInit(init: StructuredList->getInit(Init: 0), declType: T, Context&: SemaRef.Context) ==
1246	SIF_None) {
1247	unsigned DK =
1248	ExtraInitsIsError
1249	? diag::err_excess_initializers_in_char_array_initializer
1250	: diag::ext_excess_initializers_in_char_array_initializer;
1251	SemaRef.Diag(IList->getInit(Init: Index)->getBeginLoc(), DK)
1252	<< IList->getInit(Init: Index)->getSourceRange();
1253	} else if (T->isSizelessBuiltinType()) {
1254	unsigned DK = ExtraInitsIsError
1255	? diag::err_excess_initializers_for_sizeless_type
1256	: diag::ext_excess_initializers_for_sizeless_type;
1257	SemaRef.Diag(IList->getInit(Init: Index)->getBeginLoc(), DK)
1258	<< T << IList->getInit(Init: Index)->getSourceRange();
1259	} else {
1260	int initKind = T->isArrayType() ? 0 :
1261	T->isVectorType() ? 1 :
1262	T->isScalarType() ? 2 :
1263	T->isUnionType() ? 3 :
1264	4;
1265
1266	unsigned DK = ExtraInitsIsError ? diag::err_excess_initializers
1267	: diag::ext_excess_initializers;
1268	SemaRef.Diag(IList->getInit(Init: Index)->getBeginLoc(), DK)
1269	<< initKind << IList->getInit(Init: Index)->getSourceRange();
1270	}
1271	}
1272
1273	if (!VerifyOnly) {
1274	if (T->isScalarType() && IList->getNumInits() == 1 &&
1275	!isa<InitListExpr>(Val: IList->getInit(Init: 0)))
1276	warnBracedScalarInit(SemaRef, Entity, IList->getSourceRange());
1277
1278	// Warn if this is a class type that won't be an aggregate in future
1279	// versions of C++.
1280	auto *CXXRD = T->getAsCXXRecordDecl();
1281	if (CXXRD && CXXRD->hasUserDeclaredConstructor()) {
1282	// Don't warn if there's an equivalent default constructor that would be
1283	// used instead.
1284	bool HasEquivCtor = false;
1285	if (IList->getNumInits() == 0) {
1286	auto *CD = SemaRef.LookupDefaultConstructor(Class: CXXRD);
1287	HasEquivCtor = CD && !CD->isDeleted();
1288	}
1289
1290	if (!HasEquivCtor) {
1291	SemaRef.Diag(IList->getBeginLoc(),
1292	diag::warn_cxx20_compat_aggregate_init_with_ctors)
1293	<< IList->getSourceRange() << T;
1294	}
1295	}
1296	}
1297	}
1298
1299	void InitListChecker::CheckListElementTypes(const InitializedEntity &Entity,
1300	InitListExpr *IList,
1301	QualType &DeclType,
1302	bool SubobjectIsDesignatorContext,
1303	unsigned &Index,
1304	InitListExpr *StructuredList,
1305	unsigned &StructuredIndex,
1306	bool TopLevelObject) {
1307	if (DeclType->isAnyComplexType() && SubobjectIsDesignatorContext) {
1308	// Explicitly braced initializer for complex type can be real+imaginary
1309	// parts.
1310	CheckComplexType(Entity, IList, DeclType, Index,
1311	StructuredList, StructuredIndex);
1312	} else if (DeclType->isScalarType()) {
1313	CheckScalarType(Entity, IList, DeclType, Index,
1314	StructuredList, StructuredIndex);
1315	} else if (DeclType->isVectorType()) {
1316	CheckVectorType(Entity, IList, DeclType, Index,
1317	StructuredList, StructuredIndex);
1318	} else if (const RecordDecl *RD = getRecordDecl(DeclType)) {
1319	auto Bases =
1320	CXXRecordDecl::base_class_const_range(CXXRecordDecl::base_class_const_iterator(),
1321	CXXRecordDecl::base_class_const_iterator());
1322	if (DeclType->isRecordType()) {
1323	assert(DeclType->isAggregateType() &&
1324	"non-aggregate records should be handed in CheckSubElementType");
1325	if (auto *CXXRD = dyn_cast<CXXRecordDecl>(Val: RD))
1326	Bases = CXXRD->bases();
1327	} else {
1328	Bases = cast<CXXRecordDecl>(Val: RD)->bases();
1329	}
1330	CheckStructUnionTypes(Entity, IList, DeclType, Bases, Field: RD->field_begin(),
1331	SubobjectIsDesignatorContext, Index, StructuredList,
1332	StructuredIndex, TopLevelObject);
1333	} else if (DeclType->isArrayType()) {
1334	llvm::APSInt Zero(
1335	SemaRef.Context.getTypeSize(T: SemaRef.Context.getSizeType()),
1336	false);
1337	CheckArrayType(Entity, IList, DeclType, elementIndex: Zero,
1338	SubobjectIsDesignatorContext, Index,
1339	StructuredList, StructuredIndex);
1340	} else if (DeclType->isVoidType() || DeclType->isFunctionType()) {
1341	// This type is invalid, issue a diagnostic.
1342	++Index;
1343	if (!VerifyOnly)
1344	SemaRef.Diag(IList->getBeginLoc(), diag::err_illegal_initializer_type)
1345	<< DeclType;
1346	hadError = true;
1347	} else if (DeclType->isReferenceType()) {
1348	CheckReferenceType(Entity, IList, DeclType, Index,
1349	StructuredList, StructuredIndex);
1350	} else if (DeclType->isObjCObjectType()) {
1351	if (!VerifyOnly)
1352	SemaRef.Diag(IList->getBeginLoc(), diag::err_init_objc_class) << DeclType;
1353	hadError = true;
1354	} else if (DeclType->isOCLIntelSubgroupAVCType() ||
1355	DeclType->isSizelessBuiltinType()) {
1356	// Checks for scalar type are sufficient for these types too.
1357	CheckScalarType(Entity, IList, DeclType, Index, StructuredList,
1358	StructuredIndex);
1359	} else if (DeclType->isDependentType()) {
1360	// C++ [over.match.class.deduct]p1.5:
1361	// brace elision is not considered for any aggregate element that has a
1362	// dependent non-array type or an array type with a value-dependent bound
1363	++Index;
1364	assert(AggrDeductionCandidateParamTypes);
1365	AggrDeductionCandidateParamTypes->push_back(Elt: DeclType);
1366	} else {
1367	if (!VerifyOnly)
1368	SemaRef.Diag(IList->getBeginLoc(), diag::err_illegal_initializer_type)
1369	<< DeclType;
1370	hadError = true;
1371	}
1372	}
1373
1374	void InitListChecker::CheckSubElementType(const InitializedEntity &Entity,
1375	InitListExpr *IList,
1376	QualType ElemType,
1377	unsigned &Index,
1378	InitListExpr *StructuredList,
1379	unsigned &StructuredIndex,
1380	bool DirectlyDesignated) {
1381	Expr *expr = IList->getInit(Init: Index);
1382
1383	if (ElemType->isReferenceType())
1384	return CheckReferenceType(Entity, IList, DeclType: ElemType, Index,
1385	StructuredList, StructuredIndex);
1386
1387	if (InitListExpr *SubInitList = dyn_cast<InitListExpr>(Val: expr)) {
1388	if (SubInitList->getNumInits() == 1 &&
1389	IsStringInit(init: SubInitList->getInit(Init: 0), declType: ElemType, Context&: SemaRef.Context) ==
1390	SIF_None) {
1391	// FIXME: It would be more faithful and no less correct to include an
1392	// InitListExpr in the semantic form of the initializer list in this case.
1393	expr = SubInitList->getInit(Init: 0);
1394	}
1395	// Nested aggregate initialization and C++ initialization are handled later.
1396	} else if (isa<ImplicitValueInitExpr>(Val: expr)) {
1397	// This happens during template instantiation when we see an InitListExpr
1398	// that we've already checked once.
1399	assert(SemaRef.Context.hasSameType(expr->getType(), ElemType) &&
1400	"found implicit initialization for the wrong type");
1401	UpdateStructuredListElement(StructuredList, StructuredIndex, expr);
1402	++Index;
1403	return;
1404	}
1405
1406	if (SemaRef.getLangOpts().CPlusPlus || isa<InitListExpr>(Val: expr)) {
1407	// C++ [dcl.init.aggr]p2:
1408	// Each member is copy-initialized from the corresponding
1409	// initializer-clause.
1410
1411	// FIXME: Better EqualLoc?
1412	InitializationKind Kind =
1413	InitializationKind::CreateCopy(InitLoc: expr->getBeginLoc(), EqualLoc: SourceLocation());
1414
1415	// Vector elements can be initialized from other vectors in which case
1416	// we need initialization entity with a type of a vector (and not a vector
1417	// element!) initializing multiple vector elements.
1418	auto TmpEntity =
1419	(ElemType->isExtVectorType() && !Entity.getType()->isExtVectorType())
1420	? InitializedEntity::InitializeTemporary(Type: ElemType)
1421	: Entity;
1422
1423	if (TmpEntity.getType()->isDependentType()) {
1424	// C++ [over.match.class.deduct]p1.5:
1425	// brace elision is not considered for any aggregate element that has a
1426	// dependent non-array type or an array type with a value-dependent
1427	// bound
1428	assert(AggrDeductionCandidateParamTypes);
1429	if (!isa_and_nonnull<ConstantArrayType>(
1430	Val: SemaRef.Context.getAsArrayType(T: ElemType))) {
1431	++Index;
1432	AggrDeductionCandidateParamTypes->push_back(Elt: ElemType);
1433	return;
1434	}
1435	} else {
1436	InitializationSequence Seq(SemaRef, TmpEntity, Kind, expr,
1437	/*TopLevelOfInitList*/ true);
1438	// C++14 [dcl.init.aggr]p13:
1439	// If the assignment-expression can initialize a member, the member is
1440	// initialized. Otherwise [...] brace elision is assumed
1441	//
1442	// Brace elision is never performed if the element is not an
1443	// assignment-expression.
1444	if (Seq || isa<InitListExpr>(Val: expr)) {
1445	if (!VerifyOnly) {
1446	ExprResult Result = Seq.Perform(S&: SemaRef, Entity: TmpEntity, Kind, Args: expr);
1447	if (Result.isInvalid())
1448	hadError = true;
1449
1450	UpdateStructuredListElement(StructuredList, StructuredIndex,
1451	expr: Result.getAs<Expr>());
1452	} else if (!Seq) {
1453	hadError = true;
1454	} else if (StructuredList) {
1455	UpdateStructuredListElement(StructuredList, StructuredIndex,
1456	getDummyInit());
1457	}
1458	++Index;
1459	if (AggrDeductionCandidateParamTypes)
1460	AggrDeductionCandidateParamTypes->push_back(Elt: ElemType);
1461	return;
1462	}
1463	}
1464
1465	// Fall through for subaggregate initialization
1466	} else if (ElemType->isScalarType() || ElemType->isAtomicType()) {
1467	// FIXME: Need to handle atomic aggregate types with implicit init lists.
1468	return CheckScalarType(Entity, IList, DeclType: ElemType, Index,
1469	StructuredList, StructuredIndex);
1470	} else if (const ArrayType *arrayType =
1471	SemaRef.Context.getAsArrayType(T: ElemType)) {
1472	// arrayType can be incomplete if we're initializing a flexible
1473	// array member. There's nothing we can do with the completed
1474	// type here, though.
1475
1476	if (IsStringInit(Init: expr, AT: arrayType, Context&: SemaRef.Context) == SIF_None) {
1477	// FIXME: Should we do this checking in verify-only mode?
1478	if (!VerifyOnly)
1479	CheckStringInit(Str: expr, DeclT&: ElemType, AT: arrayType, S&: SemaRef);
1480	if (StructuredList)
1481	UpdateStructuredListElement(StructuredList, StructuredIndex, expr);
1482	++Index;
1483	return;
1484	}
1485
1486	// Fall through for subaggregate initialization.
1487
1488	} else {
1489	assert((ElemType->isRecordType() || ElemType->isVectorType() ||
1490	ElemType->isOpenCLSpecificType()) && "Unexpected type");
1491
1492	// C99 6.7.8p13:
1493	//
1494	// The initializer for a structure or union object that has
1495	// automatic storage duration shall be either an initializer
1496	// list as described below, or a single expression that has
1497	// compatible structure or union type. In the latter case, the
1498	// initial value of the object, including unnamed members, is
1499	// that of the expression.
1500	ExprResult ExprRes = expr;
1501	if (SemaRef.CheckSingleAssignmentConstraints(
1502	LHSType: ElemType, RHS&: ExprRes, Diagnose: !VerifyOnly) != Sema::Incompatible) {
1503	if (ExprRes.isInvalid())
1504	hadError = true;
1505	else {
1506	ExprRes = SemaRef.DefaultFunctionArrayLvalueConversion(E: ExprRes.get());
1507	if (ExprRes.isInvalid())
1508	hadError = true;
1509	}
1510	UpdateStructuredListElement(StructuredList, StructuredIndex,
1511	expr: ExprRes.getAs<Expr>());
1512	++Index;
1513	return;
1514	}
1515	ExprRes.get();
1516	// Fall through for subaggregate initialization
1517	}
1518
1519	// C++ [dcl.init.aggr]p12:
1520	//
1521	// [...] Otherwise, if the member is itself a non-empty
1522	// subaggregate, brace elision is assumed and the initializer is
1523	// considered for the initialization of the first member of
1524	// the subaggregate.
1525	// OpenCL vector initializer is handled elsewhere.
1526	if ((!SemaRef.getLangOpts().OpenCL && ElemType->isVectorType()) ||
1527	ElemType->isAggregateType()) {
1528	CheckImplicitInitList(Entity, ParentIList: IList, T: ElemType, Index, StructuredList,
1529	StructuredIndex);
1530	++StructuredIndex;
1531
1532	// In C++20, brace elision is not permitted for a designated initializer.
1533	if (DirectlyDesignated && SemaRef.getLangOpts().CPlusPlus && !hadError) {
1534	if (InOverloadResolution)
1535	hadError = true;
1536	if (!VerifyOnly) {
1537	SemaRef.Diag(expr->getBeginLoc(),
1538	diag::ext_designated_init_brace_elision)
1539	<< expr->getSourceRange()
1540	<< FixItHint::CreateInsertion(expr->getBeginLoc(), "{")
1541	<< FixItHint::CreateInsertion(
1542	SemaRef.getLocForEndOfToken(expr->getEndLoc()), "}");
1543	}
1544	}
1545	} else {
1546	if (!VerifyOnly) {
1547	// We cannot initialize this element, so let PerformCopyInitialization
1548	// produce the appropriate diagnostic. We already checked that this
1549	// initialization will fail.
1550	ExprResult Copy =
1551	SemaRef.PerformCopyInitialization(Entity, EqualLoc: SourceLocation(), Init: expr,
1552	/*TopLevelOfInitList=*/true);
1553	(void)Copy;
1554	assert(Copy.isInvalid() &&
1555	"expected non-aggregate initialization to fail");
1556	}
1557	hadError = true;
1558	++Index;
1559	++StructuredIndex;
1560	}
1561	}
1562
1563	void InitListChecker::CheckComplexType(const InitializedEntity &Entity,
1564	InitListExpr *IList, QualType DeclType,
1565	unsigned &Index,
1566	InitListExpr *StructuredList,
1567	unsigned &StructuredIndex) {
1568	assert(Index == 0 && "Index in explicit init list must be zero");
1569
1570	// As an extension, clang supports complex initializers, which initialize
1571	// a complex number component-wise. When an explicit initializer list for
1572	// a complex number contains two initializers, this extension kicks in:
1573	// it expects the initializer list to contain two elements convertible to
1574	// the element type of the complex type. The first element initializes
1575	// the real part, and the second element intitializes the imaginary part.
1576
1577	if (IList->getNumInits() < 2)
1578	return CheckScalarType(Entity, IList, DeclType, Index, StructuredList,
1579	StructuredIndex);
1580
1581	// This is an extension in C. (The builtin _Complex type does not exist
1582	// in the C++ standard.)
1583	if (!SemaRef.getLangOpts().CPlusPlus && !VerifyOnly)
1584	SemaRef.Diag(IList->getBeginLoc(), diag::ext_complex_component_init)
1585	<< IList->getSourceRange();
1586
1587	// Initialize the complex number.
1588	QualType elementType = DeclType->castAs<ComplexType>()->getElementType();
1589	InitializedEntity ElementEntity =
1590	InitializedEntity::InitializeElement(Context&: SemaRef.Context, Index: 0, Parent: Entity);
1591
1592	for (unsigned i = 0; i < 2; ++i) {
1593	ElementEntity.setElementIndex(Index);
1594	CheckSubElementType(Entity: ElementEntity, IList, ElemType: elementType, Index,
1595	StructuredList, StructuredIndex);
1596	}
1597	}
1598
1599	void InitListChecker::CheckScalarType(const InitializedEntity &Entity,
1600	InitListExpr *IList, QualType DeclType,
1601	unsigned &Index,
1602	InitListExpr *StructuredList,
1603	unsigned &StructuredIndex) {
1604	if (Index >= IList->getNumInits()) {
1605	if (!VerifyOnly) {
1606	if (SemaRef.getLangOpts().CPlusPlus) {
1607	if (DeclType->isSizelessBuiltinType())
1608	SemaRef.Diag(IList->getBeginLoc(),
1609	SemaRef.getLangOpts().CPlusPlus11
1610	? diag::warn_cxx98_compat_empty_sizeless_initializer
1611	: diag::err_empty_sizeless_initializer)
1612	<< DeclType << IList->getSourceRange();
1613	else
1614	SemaRef.Diag(IList->getBeginLoc(),
1615	SemaRef.getLangOpts().CPlusPlus11
1616	? diag::warn_cxx98_compat_empty_scalar_initializer
1617	: diag::err_empty_scalar_initializer)
1618	<< IList->getSourceRange();
1619	}
1620	}
1621	hadError =
1622	SemaRef.getLangOpts().CPlusPlus && !SemaRef.getLangOpts().CPlusPlus11;
1623	++Index;
1624	++StructuredIndex;
1625	return;
1626	}
1627
1628	Expr *expr = IList->getInit(Init: Index);
1629	if (InitListExpr *SubIList = dyn_cast<InitListExpr>(Val: expr)) {
1630	// FIXME: This is invalid, and accepting it causes overload resolution
1631	// to pick the wrong overload in some corner cases.
1632	if (!VerifyOnly)
1633	SemaRef.Diag(SubIList->getBeginLoc(), diag::ext_many_braces_around_init)
1634	<< DeclType->isSizelessBuiltinType() << SubIList->getSourceRange();
1635
1636	CheckScalarType(Entity, IList: SubIList, DeclType, Index, StructuredList,
1637	StructuredIndex);
1638	return;
1639	} else if (isa<DesignatedInitExpr>(Val: expr)) {
1640	if (!VerifyOnly)
1641	SemaRef.Diag(expr->getBeginLoc(),
1642	diag::err_designator_for_scalar_or_sizeless_init)
1643	<< DeclType->isSizelessBuiltinType() << DeclType
1644	<< expr->getSourceRange();
1645	hadError = true;
1646	++Index;
1647	++StructuredIndex;
1648	return;
1649	}
1650
1651	ExprResult Result;
1652	if (VerifyOnly) {
1653	if (SemaRef.CanPerformCopyInitialization(Entity, Init: expr))
1654	Result = getDummyInit();
1655	else
1656	Result = ExprError();
1657	} else {
1658	Result =
1659	SemaRef.PerformCopyInitialization(Entity, EqualLoc: expr->getBeginLoc(), Init: expr,
1660	/*TopLevelOfInitList=*/true);
1661	}
1662
1663	Expr *ResultExpr = nullptr;
1664
1665	if (Result.isInvalid())
1666	hadError = true; // types weren't compatible.
1667	else {
1668	ResultExpr = Result.getAs<Expr>();
1669
1670	if (ResultExpr != expr && !VerifyOnly) {
1671	// The type was promoted, update initializer list.
1672	// FIXME: Why are we updating the syntactic init list?
1673	IList->setInit(Init: Index, expr: ResultExpr);
1674	}
1675	}
1676	UpdateStructuredListElement(StructuredList, StructuredIndex, expr: ResultExpr);
1677	++Index;
1678	if (AggrDeductionCandidateParamTypes)
1679	AggrDeductionCandidateParamTypes->push_back(Elt: DeclType);
1680	}
1681
1682	void InitListChecker::CheckReferenceType(const InitializedEntity &Entity,
1683	InitListExpr *IList, QualType DeclType,
1684	unsigned &Index,
1685	InitListExpr *StructuredList,
1686	unsigned &StructuredIndex) {
1687	if (Index >= IList->getNumInits()) {
1688	// FIXME: It would be wonderful if we could point at the actual member. In
1689	// general, it would be useful to pass location information down the stack,
1690	// so that we know the location (or decl) of the "current object" being
1691	// initialized.
1692	if (!VerifyOnly)
1693	SemaRef.Diag(IList->getBeginLoc(),
1694	diag::err_init_reference_member_uninitialized)
1695	<< DeclType << IList->getSourceRange();
1696	hadError = true;
1697	++Index;
1698	++StructuredIndex;
1699	return;
1700	}
1701
1702	Expr *expr = IList->getInit(Init: Index);
1703	if (isa<InitListExpr>(Val: expr) && !SemaRef.getLangOpts().CPlusPlus11) {
1704	if (!VerifyOnly)
1705	SemaRef.Diag(IList->getBeginLoc(), diag::err_init_non_aggr_init_list)
1706	<< DeclType << IList->getSourceRange();
1707	hadError = true;
1708	++Index;
1709	++StructuredIndex;
1710	return;
1711	}
1712
1713	ExprResult Result;
1714	if (VerifyOnly) {
1715	if (SemaRef.CanPerformCopyInitialization(Entity,Init: expr))
1716	Result = getDummyInit();
1717	else
1718	Result = ExprError();
1719	} else {
1720	Result =
1721	SemaRef.PerformCopyInitialization(Entity, EqualLoc: expr->getBeginLoc(), Init: expr,
1722	/*TopLevelOfInitList=*/true);
1723	}
1724
1725	if (Result.isInvalid())
1726	hadError = true;
1727
1728	expr = Result.getAs<Expr>();
1729	// FIXME: Why are we updating the syntactic init list?
1730	if (!VerifyOnly && expr)
1731	IList->setInit(Init: Index, expr);
1732
1733	UpdateStructuredListElement(StructuredList, StructuredIndex, expr);
1734	++Index;
1735	if (AggrDeductionCandidateParamTypes)
1736	AggrDeductionCandidateParamTypes->push_back(Elt: DeclType);
1737	}
1738
1739	void InitListChecker::CheckVectorType(const InitializedEntity &Entity,
1740	InitListExpr *IList, QualType DeclType,
1741	unsigned &Index,
1742	InitListExpr *StructuredList,
1743	unsigned &StructuredIndex) {
1744	const VectorType *VT = DeclType->castAs<VectorType>();
1745	unsigned maxElements = VT->getNumElements();
1746	unsigned numEltsInit = 0;
1747	QualType elementType = VT->getElementType();
1748
1749	if (Index >= IList->getNumInits()) {
1750	// Make sure the element type can be value-initialized.
1751	CheckEmptyInitializable(
1752	Entity: InitializedEntity::InitializeElement(Context&: SemaRef.Context, Index: 0, Parent: Entity),
1753	Loc: IList->getEndLoc());
1754	return;
1755	}
1756
1757	if (!SemaRef.getLangOpts().OpenCL && !SemaRef.getLangOpts().HLSL ) {
1758	// If the initializing element is a vector, try to copy-initialize
1759	// instead of breaking it apart (which is doomed to failure anyway).
1760	Expr *Init = IList->getInit(Init: Index);
1761	if (!isa<InitListExpr>(Val: Init) && Init->getType()->isVectorType()) {
1762	ExprResult Result;
1763	if (VerifyOnly) {
1764	if (SemaRef.CanPerformCopyInitialization(Entity, Init))
1765	Result = getDummyInit();
1766	else
1767	Result = ExprError();
1768	} else {
1769	Result =
1770	SemaRef.PerformCopyInitialization(Entity, EqualLoc: Init->getBeginLoc(), Init,
1771	/*TopLevelOfInitList=*/true);
1772	}
1773
1774	Expr *ResultExpr = nullptr;
1775	if (Result.isInvalid())
1776	hadError = true; // types weren't compatible.
1777	else {
1778	ResultExpr = Result.getAs<Expr>();
1779
1780	if (ResultExpr != Init && !VerifyOnly) {
1781	// The type was promoted, update initializer list.
1782	// FIXME: Why are we updating the syntactic init list?
1783	IList->setInit(Init: Index, expr: ResultExpr);
1784	}
1785	}
1786	UpdateStructuredListElement(StructuredList, StructuredIndex, expr: ResultExpr);
1787	++Index;
1788	if (AggrDeductionCandidateParamTypes)
1789	AggrDeductionCandidateParamTypes->push_back(Elt: elementType);
1790	return;
1791	}
1792
1793	InitializedEntity ElementEntity =
1794	InitializedEntity::InitializeElement(Context&: SemaRef.Context, Index: 0, Parent: Entity);
1795
1796	for (unsigned i = 0; i < maxElements; ++i, ++numEltsInit) {
1797	// Don't attempt to go past the end of the init list
1798	if (Index >= IList->getNumInits()) {
1799	CheckEmptyInitializable(Entity: ElementEntity, Loc: IList->getEndLoc());
1800	break;
1801	}
1802
1803	ElementEntity.setElementIndex(Index);
1804	CheckSubElementType(Entity: ElementEntity, IList, ElemType: elementType, Index,
1805	StructuredList, StructuredIndex);
1806	}
1807
1808	if (VerifyOnly)
1809	return;
1810
1811	bool isBigEndian = SemaRef.Context.getTargetInfo().isBigEndian();
1812	const VectorType *T = Entity.getType()->castAs<VectorType>();
1813	if (isBigEndian && (T->getVectorKind() == VectorKind::Neon ||
1814	T->getVectorKind() == VectorKind::NeonPoly)) {
1815	// The ability to use vector initializer lists is a GNU vector extension
1816	// and is unrelated to the NEON intrinsics in arm_neon.h. On little
1817	// endian machines it works fine, however on big endian machines it
1818	// exhibits surprising behaviour:
1819	//
1820	// uint32x2_t x = {42, 64};
1821	// return vget_lane_u32(x, 0); // Will return 64.
1822	//
1823	// Because of this, explicitly call out that it is non-portable.
1824	//
1825	SemaRef.Diag(IList->getBeginLoc(),
1826	diag::warn_neon_vector_initializer_non_portable);
1827
1828	const char *typeCode;
1829	unsigned typeSize = SemaRef.Context.getTypeSize(T: elementType);
1830
1831	if (elementType->isFloatingType())
1832	typeCode = "f";
1833	else if (elementType->isSignedIntegerType())
1834	typeCode = "s";
1835	else if (elementType->isUnsignedIntegerType())
1836	typeCode = "u";
1837	else
1838	llvm_unreachable("Invalid element type!");
1839
1840	SemaRef.Diag(IList->getBeginLoc(),
1841	SemaRef.Context.getTypeSize(VT) > 64
1842	? diag::note_neon_vector_initializer_non_portable_q
1843	: diag::note_neon_vector_initializer_non_portable)
1844	<< typeCode << typeSize;
1845	}
1846
1847	return;
1848	}
1849
1850	InitializedEntity ElementEntity =
1851	InitializedEntity::InitializeElement(Context&: SemaRef.Context, Index: 0, Parent: Entity);
1852
1853	// OpenCL and HLSL initializers allow vectors to be constructed from vectors.
1854	for (unsigned i = 0; i < maxElements; ++i) {
1855	// Don't attempt to go past the end of the init list
1856	if (Index >= IList->getNumInits())
1857	break;
1858
1859	ElementEntity.setElementIndex(Index);
1860
1861	QualType IType = IList->getInit(Init: Index)->getType();
1862	if (!IType->isVectorType()) {
1863	CheckSubElementType(Entity: ElementEntity, IList, ElemType: elementType, Index,
1864	StructuredList, StructuredIndex);
1865	++numEltsInit;
1866	} else {
1867	QualType VecType;
1868	const VectorType *IVT = IType->castAs<VectorType>();
1869	unsigned numIElts = IVT->getNumElements();
1870
1871	if (IType->isExtVectorType())
1872	VecType = SemaRef.Context.getExtVectorType(VectorType: elementType, NumElts: numIElts);
1873	else
1874	VecType = SemaRef.Context.getVectorType(VectorType: elementType, NumElts: numIElts,
1875	VecKind: IVT->getVectorKind());
1876	CheckSubElementType(Entity: ElementEntity, IList, ElemType: VecType, Index,
1877	StructuredList, StructuredIndex);
1878	numEltsInit += numIElts;
1879	}
1880	}
1881
1882	// OpenCL and HLSL require all elements to be initialized.
1883	if (numEltsInit != maxElements) {
1884	if (!VerifyOnly)
1885	SemaRef.Diag(IList->getBeginLoc(),
1886	diag::err_vector_incorrect_num_initializers)
1887	<< (numEltsInit < maxElements) << maxElements << numEltsInit;
1888	hadError = true;
1889	}
1890	}
1891
1892	/// Check if the type of a class element has an accessible destructor, and marks
1893	/// it referenced. Returns true if we shouldn't form a reference to the
1894	/// destructor.
1895	///
1896	/// Aggregate initialization requires a class element's destructor be
1897	/// accessible per 11.6.1 [dcl.init.aggr]:
1898	///
1899	/// The destructor for each element of class type is potentially invoked
1900	/// (15.4 [class.dtor]) from the context where the aggregate initialization
1901	/// occurs.
1902	static bool checkDestructorReference(QualType ElementType, SourceLocation Loc,
1903	Sema &SemaRef) {
1904	auto *CXXRD = ElementType->getAsCXXRecordDecl();
1905	if (!CXXRD)
1906	return false;
1907
1908	CXXDestructorDecl *Destructor = SemaRef.LookupDestructor(Class: CXXRD);
1909	SemaRef.CheckDestructorAccess(Loc, Destructor,
1910	SemaRef.PDiag(diag::err_access_dtor_temp)
1911	<< ElementType);
1912	SemaRef.MarkFunctionReferenced(Loc, Destructor);
1913	return SemaRef.DiagnoseUseOfDecl(Destructor, Loc);
1914	}
1915
1916	void InitListChecker::CheckArrayType(const InitializedEntity &Entity,
1917	InitListExpr *IList, QualType &DeclType,
1918	llvm::APSInt elementIndex,
1919	bool SubobjectIsDesignatorContext,
1920	unsigned &Index,
1921	InitListExpr *StructuredList,
1922	unsigned &StructuredIndex) {
1923	const ArrayType *arrayType = SemaRef.Context.getAsArrayType(T: DeclType);
1924
1925	if (!VerifyOnly) {
1926	if (checkDestructorReference(ElementType: arrayType->getElementType(),
1927	Loc: IList->getEndLoc(), SemaRef)) {
1928	hadError = true;
1929	return;
1930	}
1931	}
1932
1933	// Check for the special-case of initializing an array with a string.
1934	if (Index < IList->getNumInits()) {
1935	if (IsStringInit(Init: IList->getInit(Init: Index), AT: arrayType, Context&: SemaRef.Context) ==
1936	SIF_None) {
1937	// We place the string literal directly into the resulting
1938	// initializer list. This is the only place where the structure
1939	// of the structured initializer list doesn't match exactly,
1940	// because doing so would involve allocating one character
1941	// constant for each string.
1942	// FIXME: Should we do these checks in verify-only mode too?
1943	if (!VerifyOnly)
1944	CheckStringInit(Str: IList->getInit(Init: Index), DeclT&: DeclType, AT: arrayType, S&: SemaRef);
1945	if (StructuredList) {
1946	UpdateStructuredListElement(StructuredList, StructuredIndex,
1947	expr: IList->getInit(Init: Index));
1948	StructuredList->resizeInits(Context: SemaRef.Context, NumInits: StructuredIndex);
1949	}
1950	++Index;
1951	if (AggrDeductionCandidateParamTypes)
1952	AggrDeductionCandidateParamTypes->push_back(Elt: DeclType);
1953	return;
1954	}
1955	}
1956	if (const VariableArrayType *VAT = dyn_cast<VariableArrayType>(Val: arrayType)) {
1957	// Check for VLAs; in standard C it would be possible to check this
1958	// earlier, but I don't know where clang accepts VLAs (gcc accepts
1959	// them in all sorts of strange places).
1960	bool HasErr = IList->getNumInits() != 0 || SemaRef.getLangOpts().CPlusPlus;
1961	if (!VerifyOnly) {
1962	// C23 6.7.10p4: An entity of variable length array type shall not be
1963	// initialized except by an empty initializer.
1964	//
1965	// The C extension warnings are issued from ParseBraceInitializer() and
1966	// do not need to be issued here. However, we continue to issue an error
1967	// in the case there are initializers or we are compiling C++. We allow
1968	// use of VLAs in C++, but it's not clear we want to allow {} to zero
1969	// init a VLA in C++ in all cases (such as with non-trivial constructors).
1970	// FIXME: should we allow this construct in C++ when it makes sense to do
1971	// so?
1972	if (HasErr)
1973	SemaRef.Diag(VAT->getSizeExpr()->getBeginLoc(),
1974	diag::err_variable_object_no_init)
1975	<< VAT->getSizeExpr()->getSourceRange();
1976	}
1977	hadError = HasErr;
1978	++Index;
1979	++StructuredIndex;
1980	return;
1981	}
1982
1983	// We might know the maximum number of elements in advance.
1984	llvm::APSInt maxElements(elementIndex.getBitWidth(),
1985	elementIndex.isUnsigned());
1986	bool maxElementsKnown = false;
1987	if (const ConstantArrayType *CAT = dyn_cast<ConstantArrayType>(Val: arrayType)) {
1988	maxElements = CAT->getSize();
1989	elementIndex = elementIndex.extOrTrunc(width: maxElements.getBitWidth());
1990	elementIndex.setIsUnsigned(maxElements.isUnsigned());
1991	maxElementsKnown = true;
1992	}
1993
1994	QualType elementType = arrayType->getElementType();
1995	while (Index < IList->getNumInits()) {
1996	Expr *Init = IList->getInit(Init: Index);
1997	if (DesignatedInitExpr *DIE = dyn_cast<DesignatedInitExpr>(Val: Init)) {
1998	// If we're not the subobject that matches up with the '{' for
1999	// the designator, we shouldn't be handling the
2000	// designator. Return immediately.
2001	if (!SubobjectIsDesignatorContext)
2002	return;
2003
2004	// Handle this designated initializer. elementIndex will be
2005	// updated to be the next array element we'll initialize.
2006	if (CheckDesignatedInitializer(Entity, IList, DIE, DesigIdx: 0,
2007	CurrentObjectType&: DeclType, NextField: nullptr, NextElementIndex: &elementIndex, Index,
2008	StructuredList, StructuredIndex, FinishSubobjectInit: true,
2009	TopLevelObject: false)) {
2010	hadError = true;
2011	continue;
2012	}
2013
2014	if (elementIndex.getBitWidth() > maxElements.getBitWidth())
2015	maxElements = maxElements.extend(width: elementIndex.getBitWidth());
2016	else if (elementIndex.getBitWidth() < maxElements.getBitWidth())
2017	elementIndex = elementIndex.extend(width: maxElements.getBitWidth());
2018	elementIndex.setIsUnsigned(maxElements.isUnsigned());
2019
2020	// If the array is of incomplete type, keep track of the number of
2021	// elements in the initializer.
2022	if (!maxElementsKnown && elementIndex > maxElements)
2023	maxElements = elementIndex;
2024
2025	continue;
2026	}
2027
2028	// If we know the maximum number of elements, and we've already
2029	// hit it, stop consuming elements in the initializer list.
2030	if (maxElementsKnown && elementIndex == maxElements)
2031	break;
2032
2033	InitializedEntity ElementEntity =
2034	InitializedEntity::InitializeElement(Context&: SemaRef.Context, Index: StructuredIndex,
2035	Parent: Entity);
2036	// Check this element.
2037	CheckSubElementType(Entity: ElementEntity, IList, ElemType: elementType, Index,
2038	StructuredList, StructuredIndex);
2039	++elementIndex;
2040
2041	// If the array is of incomplete type, keep track of the number of
2042	// elements in the initializer.
2043	if (!maxElementsKnown && elementIndex > maxElements)
2044	maxElements = elementIndex;
2045	}
2046	if (!hadError && DeclType->isIncompleteArrayType() && !VerifyOnly) {
2047	// If this is an incomplete array type, the actual type needs to
2048	// be calculated here.
2049	llvm::APSInt Zero(maxElements.getBitWidth(), maxElements.isUnsigned());
2050	if (maxElements == Zero && !Entity.isVariableLengthArrayNew()) {
2051	// Sizing an array implicitly to zero is not allowed by ISO C,
2052	// but is supported by GNU.
2053	SemaRef.Diag(IList->getBeginLoc(), diag::ext_typecheck_zero_array_size);
2054	}
2055
2056	DeclType = SemaRef.Context.getConstantArrayType(
2057	EltTy: elementType, ArySize: maxElements, SizeExpr: nullptr, ASM: ArraySizeModifier::Normal, IndexTypeQuals: 0);
2058	}
2059	if (!hadError) {
2060	// If there are any members of the array that get value-initialized, check
2061	// that is possible. That happens if we know the bound and don't have
2062	// enough elements, or if we're performing an array new with an unknown
2063	// bound.
2064	if ((maxElementsKnown && elementIndex < maxElements) ||
2065	Entity.isVariableLengthArrayNew())
2066	CheckEmptyInitializable(
2067	Entity: InitializedEntity::InitializeElement(Context&: SemaRef.Context, Index: 0, Parent: Entity),
2068	Loc: IList->getEndLoc());
2069	}
2070	}
2071
2072	bool InitListChecker::CheckFlexibleArrayInit(const InitializedEntity &Entity,
2073	Expr *InitExpr,
2074	FieldDecl *Field,
2075	bool TopLevelObject) {
2076	// Handle GNU flexible array initializers.
2077	unsigned FlexArrayDiag;
2078	if (isa<InitListExpr>(Val: InitExpr) &&
2079	cast<InitListExpr>(Val: InitExpr)->getNumInits() == 0) {
2080	// Empty flexible array init always allowed as an extension
2081	FlexArrayDiag = diag::ext_flexible_array_init;
2082	} else if (!TopLevelObject) {
2083	// Disallow flexible array init on non-top-level object
2084	FlexArrayDiag = diag::err_flexible_array_init;
2085	} else if (Entity.getKind() != InitializedEntity::EK_Variable) {
2086	// Disallow flexible array init on anything which is not a variable.
2087	FlexArrayDiag = diag::err_flexible_array_init;
2088	} else if (cast<VarDecl>(Val: Entity.getDecl())->hasLocalStorage()) {
2089	// Disallow flexible array init on local variables.
2090	FlexArrayDiag = diag::err_flexible_array_init;
2091	} else {
2092	// Allow other cases.
2093	FlexArrayDiag = diag::ext_flexible_array_init;
2094	}
2095
2096	if (!VerifyOnly) {
2097	SemaRef.Diag(InitExpr->getBeginLoc(), FlexArrayDiag)
2098	<< InitExpr->getBeginLoc();
2099	SemaRef.Diag(Field->getLocation(), diag::note_flexible_array_member)
2100	<< Field;
2101	}
2102
2103	return FlexArrayDiag != diag::ext_flexible_array_init;
2104	}
2105
2106	void InitListChecker::CheckStructUnionTypes(
2107	const InitializedEntity &Entity, InitListExpr *IList, QualType DeclType,
2108	CXXRecordDecl::base_class_const_range Bases, RecordDecl::field_iterator Field,
2109	bool SubobjectIsDesignatorContext, unsigned &Index,
2110	InitListExpr *StructuredList, unsigned &StructuredIndex,
2111	bool TopLevelObject) {
2112	const RecordDecl *RD = getRecordDecl(DeclType);
2113
2114	// If the record is invalid, some of it's members are invalid. To avoid
2115	// confusion, we forgo checking the initializer for the entire record.
2116	if (RD->isInvalidDecl()) {
2117	// Assume it was supposed to consume a single initializer.
2118	++Index;
2119	hadError = true;
2120	return;
2121	}
2122
2123	if (RD->isUnion() && IList->getNumInits() == 0) {
2124	if (!VerifyOnly)
2125	for (FieldDecl *FD : RD->fields()) {
2126	QualType ET = SemaRef.Context.getBaseElementType(FD->getType());
2127	if (checkDestructorReference(ElementType: ET, Loc: IList->getEndLoc(), SemaRef)) {
2128	hadError = true;
2129	return;
2130	}
2131	}
2132
2133	// If there's a default initializer, use it.
2134	if (isa<CXXRecordDecl>(Val: RD) &&
2135	cast<CXXRecordDecl>(Val: RD)->hasInClassInitializer()) {
2136	if (!StructuredList)
2137	return;
2138	for (RecordDecl::field_iterator FieldEnd = RD->field_end();
2139	Field != FieldEnd; ++Field) {
2140	if (Field->hasInClassInitializer()) {
2141	StructuredList->setInitializedFieldInUnion(*Field);
2142	// FIXME: Actually build a CXXDefaultInitExpr?
2143	return;
2144	}
2145	}
2146	}
2147
2148	// Value-initialize the first member of the union that isn't an unnamed
2149	// bitfield.
2150	for (RecordDecl::field_iterator FieldEnd = RD->field_end();
2151	Field != FieldEnd; ++Field) {
2152	if (!Field->isUnnamedBitfield()) {
2153	CheckEmptyInitializable(
2154	Entity: InitializedEntity::InitializeMember(Member: *Field, Parent: &Entity),
2155	Loc: IList->getEndLoc());
2156	if (StructuredList)
2157	StructuredList->setInitializedFieldInUnion(*Field);
2158	break;
2159	}
2160	}
2161	return;
2162	}
2163
2164	bool InitializedSomething = false;
2165
2166	// If we have any base classes, they are initialized prior to the fields.
2167	for (auto I = Bases.begin(), E = Bases.end(); I != E; ++I) {
2168	auto &Base = *I;
2169	Expr *Init = Index < IList->getNumInits() ? IList->getInit(Init: Index) : nullptr;
2170
2171	// Designated inits always initialize fields, so if we see one, all
2172	// remaining base classes have no explicit initializer.
2173	if (Init && isa<DesignatedInitExpr>(Val: Init))
2174	Init = nullptr;
2175
2176	// C++ [over.match.class.deduct]p1.6:
2177	// each non-trailing aggregate element that is a pack expansion is assumed
2178	// to correspond to no elements of the initializer list, and (1.7) a
2179	// trailing aggregate element that is a pack expansion is assumed to
2180	// correspond to all remaining elements of the initializer list (if any).
2181
2182	// C++ [over.match.class.deduct]p1.9:
2183	// ... except that additional parameter packs of the form P_j... are
2184	// inserted into the parameter list in their original aggregate element
2185	// position corresponding to each non-trailing aggregate element of
2186	// type P_j that was skipped because it was a parameter pack, and the
2187	// trailing sequence of parameters corresponding to a trailing
2188	// aggregate element that is a pack expansion (if any) is replaced
2189	// by a single parameter of the form T_n....
2190	if (AggrDeductionCandidateParamTypes && Base.isPackExpansion()) {
2191	AggrDeductionCandidateParamTypes->push_back(
2192	Elt: SemaRef.Context.getPackExpansionType(Pattern: Base.getType(), NumExpansions: std::nullopt));
2193
2194	// Trailing pack expansion
2195	if (I + 1 == E && RD->field_empty()) {
2196	if (Index < IList->getNumInits())
2197	Index = IList->getNumInits();
2198	return;
2199	}
2200
2201	continue;
2202	}
2203
2204	SourceLocation InitLoc = Init ? Init->getBeginLoc() : IList->getEndLoc();
2205	InitializedEntity BaseEntity = InitializedEntity::InitializeBase(
2206	Context&: SemaRef.Context, Base: &Base, IsInheritedVirtualBase: false, Parent: &Entity);
2207	if (Init) {
2208	CheckSubElementType(Entity: BaseEntity, IList, ElemType: Base.getType(), Index,
2209	StructuredList, StructuredIndex);
2210	InitializedSomething = true;
2211	} else {
2212	CheckEmptyInitializable(Entity: BaseEntity, Loc: InitLoc);
2213	}
2214
2215	if (!VerifyOnly)
2216	if (checkDestructorReference(ElementType: Base.getType(), Loc: InitLoc, SemaRef)) {
2217	hadError = true;
2218	return;
2219	}
2220	}
2221
2222	// If structDecl is a forward declaration, this loop won't do
2223	// anything except look at designated initializers; That's okay,
2224	// because an error should get printed out elsewhere. It might be
2225	// worthwhile to skip over the rest of the initializer, though.
2226	RecordDecl::field_iterator FieldEnd = RD->field_end();
2227	size_t NumRecordDecls = llvm::count_if(RD->decls(), [&](const Decl *D) {
2228	return isa<FieldDecl>(Val: D) || isa<RecordDecl>(Val: D);
2229	});
2230	bool CheckForMissingFields =
2231	!IList->isIdiomaticZeroInitializer(LangOpts: SemaRef.getLangOpts());
2232	bool HasDesignatedInit = false;
2233
2234	llvm::SmallPtrSet<FieldDecl *, 4> InitializedFields;
2235
2236	while (Index < IList->getNumInits()) {
2237	Expr *Init = IList->getInit(Init: Index);
2238	SourceLocation InitLoc = Init->getBeginLoc();
2239
2240	if (DesignatedInitExpr *DIE = dyn_cast<DesignatedInitExpr>(Val: Init)) {
2241	// If we're not the subobject that matches up with the '{' for
2242	// the designator, we shouldn't be handling the
2243	// designator. Return immediately.
2244	if (!SubobjectIsDesignatorContext)
2245	return;
2246
2247	HasDesignatedInit = true;
2248
2249	// Handle this designated initializer. Field will be updated to
2250	// the next field that we'll be initializing.
2251	bool DesignatedInitFailed = CheckDesignatedInitializer(
2252	Entity, IList, DIE, DesigIdx: 0, CurrentObjectType&: DeclType, NextField: &Field, NextElementIndex: nullptr, Index,
2253	StructuredList, StructuredIndex, FinishSubobjectInit: true, TopLevelObject);
2254	if (DesignatedInitFailed)
2255	hadError = true;
2256
2257	// Find the field named by the designated initializer.
2258	DesignatedInitExpr::Designator *D = DIE->getDesignator(Idx: 0);
2259	if (!VerifyOnly && D->isFieldDesignator()) {
2260	FieldDecl *F = D->getFieldDecl();
2261	InitializedFields.insert(Ptr: F);
2262	if (!DesignatedInitFailed) {
2263	QualType ET = SemaRef.Context.getBaseElementType(F->getType());
2264	if (checkDestructorReference(ElementType: ET, Loc: InitLoc, SemaRef)) {
2265	hadError = true;
2266	return;
2267	}
2268	}
2269	}
2270
2271	InitializedSomething = true;
2272
2273	// Disable check for missing fields when designators are used.
2274	// This matches gcc behaviour.
2275	if (!SemaRef.getLangOpts().CPlusPlus)
2276	CheckForMissingFields = false;
2277	continue;
2278	}
2279
2280	// Check if this is an initializer of forms:
2281	//
2282	// struct foo f = {};
2283	// struct foo g = {0};
2284	//
2285	// These are okay for randomized structures. [C99 6.7.8p19]
2286	//
2287	// Also, if there is only one element in the structure, we allow something
2288	// like this, because it's really not randomized in the tranditional sense.
2289	//
2290	// struct foo h = {bar};
2291	auto IsZeroInitializer = [&](const Expr *I) {
2292	if (IList->getNumInits() == 1) {
2293	if (NumRecordDecls == 1)
2294	return true;
2295	if (const auto *IL = dyn_cast<IntegerLiteral>(I))
2296	return IL->getValue().isZero();
2297	}
2298	return false;
2299	};
2300
2301	// Don't allow non-designated initializers on randomized structures.
2302	if (RD->isRandomized() && !IsZeroInitializer(Init)) {
2303	if (!VerifyOnly)
2304	SemaRef.Diag(InitLoc, diag::err_non_designated_init_used);
2305	hadError = true;
2306	break;
2307	}
2308
2309	if (Field == FieldEnd) {
2310	// We've run out of fields. We're done.
2311	break;
2312	}
2313
2314	// We've already initialized a member of a union. We're done.
2315	if (InitializedSomething && RD->isUnion())
2316	break;
2317
2318	// If we've hit the flexible array member at the end, we're done.
2319	if (Field->getType()->isIncompleteArrayType())
2320	break;
2321
2322	if (Field->isUnnamedBitfield()) {
2323	// Don't initialize unnamed bitfields, e.g. "int : 20;"
2324	++Field;
2325	continue;
2326	}
2327
2328	// Make sure we can use this declaration.
2329	bool InvalidUse;
2330	if (VerifyOnly)
2331	InvalidUse = !SemaRef.CanUseDecl(*Field, TreatUnavailableAsInvalid);
2332	else
2333	InvalidUse = SemaRef.DiagnoseUseOfDecl(
2334	D: *Field, Locs: IList->getInit(Init: Index)->getBeginLoc());
2335	if (InvalidUse) {
2336	++Index;
2337	++Field;
2338	hadError = true;
2339	continue;
2340	}
2341
2342	if (!VerifyOnly) {
2343	QualType ET = SemaRef.Context.getBaseElementType(Field->getType());
2344	if (checkDestructorReference(ElementType: ET, Loc: InitLoc, SemaRef)) {
2345	hadError = true;
2346	return;
2347	}
2348	}
2349
2350	InitializedEntity MemberEntity =
2351	InitializedEntity::InitializeMember(Member: *Field, Parent: &Entity);
2352	CheckSubElementType(Entity: MemberEntity, IList, ElemType: Field->getType(), Index,
2353	StructuredList, StructuredIndex);
2354	InitializedSomething = true;
2355	InitializedFields.insert(Ptr: *Field);
2356
2357	if (RD->isUnion() && StructuredList) {
2358	// Initialize the first field within the union.
2359	StructuredList->setInitializedFieldInUnion(*Field);
2360	}
2361
2362	++Field;
2363	}
2364
2365	// Emit warnings for missing struct field initializers.
2366	if (!VerifyOnly && InitializedSomething && CheckForMissingFields &&
2367	!RD->isUnion()) {
2368	// It is possible we have one or more unnamed bitfields remaining.
2369	// Find first (if any) named field and emit warning.
2370	for (RecordDecl::field_iterator it = HasDesignatedInit ? RD->field_begin()
2371	: Field,
2372	end = RD->field_end();
2373	it != end; ++it) {
2374	if (HasDesignatedInit && InitializedFields.count(Ptr: *it))
2375	continue;
2376
2377	if (!it->isUnnamedBitfield() && !it->hasInClassInitializer() &&
2378	!it->getType()->isIncompleteArrayType()) {
2379	SemaRef.Diag(IList->getSourceRange().getEnd(),
2380	diag::warn_missing_field_initializers)
2381	<< *it;
2382	break;
2383	}
2384	}
2385	}
2386
2387	// Check that any remaining fields can be value-initialized if we're not
2388	// building a structured list. (If we are, we'll check this later.)
2389	if (!StructuredList && Field != FieldEnd && !RD->isUnion() &&
2390	!Field->getType()->isIncompleteArrayType()) {
2391	for (; Field != FieldEnd && !hadError; ++Field) {
2392	if (!Field->isUnnamedBitfield() && !Field->hasInClassInitializer())
2393	CheckEmptyInitializable(
2394	Entity: InitializedEntity::InitializeMember(Member: *Field, Parent: &Entity),
2395	Loc: IList->getEndLoc());
2396	}
2397	}
2398
2399	// Check that the types of the remaining fields have accessible destructors.
2400	if (!VerifyOnly) {
2401	// If the initializer expression has a designated initializer, check the
2402	// elements for which a designated initializer is not provided too.
2403	RecordDecl::field_iterator I = HasDesignatedInit ? RD->field_begin()
2404	: Field;
2405	for (RecordDecl::field_iterator E = RD->field_end(); I != E; ++I) {
2406	QualType ET = SemaRef.Context.getBaseElementType(I->getType());
2407	if (checkDestructorReference(ElementType: ET, Loc: IList->getEndLoc(), SemaRef)) {
2408	hadError = true;
2409	return;
2410	}
2411	}
2412	}
2413
2414	if (Field == FieldEnd || !Field->getType()->isIncompleteArrayType() ||
2415	Index >= IList->getNumInits())
2416	return;
2417
2418	if (CheckFlexibleArrayInit(Entity, InitExpr: IList->getInit(Init: Index), Field: *Field,
2419	TopLevelObject)) {
2420	hadError = true;
2421	++Index;
2422	return;
2423	}
2424
2425	InitializedEntity MemberEntity =
2426	InitializedEntity::InitializeMember(Member: *Field, Parent: &Entity);
2427
2428	if (isa<InitListExpr>(Val: IList->getInit(Init: Index)) ||
2429	AggrDeductionCandidateParamTypes)
2430	CheckSubElementType(Entity: MemberEntity, IList, ElemType: Field->getType(), Index,
2431	StructuredList, StructuredIndex);
2432	else
2433	CheckImplicitInitList(Entity: MemberEntity, ParentIList: IList, T: Field->getType(), Index,
2434	StructuredList, StructuredIndex);
2435	}
2436
2437	/// Expand a field designator that refers to a member of an
2438	/// anonymous struct or union into a series of field designators that
2439	/// refers to the field within the appropriate subobject.
2440	///
2441	static void ExpandAnonymousFieldDesignator(Sema &SemaRef,
2442	DesignatedInitExpr *DIE,
2443	unsigned DesigIdx,
2444	IndirectFieldDecl *IndirectField) {
2445	typedef DesignatedInitExpr::Designator Designator;
2446
2447	// Build the replacement designators.
2448	SmallVector<Designator, 4> Replacements;
2449	for (IndirectFieldDecl::chain_iterator PI = IndirectField->chain_begin(),
2450	PE = IndirectField->chain_end(); PI != PE; ++PI) {
2451	if (PI + 1 == PE)
2452	Replacements.push_back(Elt: Designator::CreateFieldDesignator(
2453	FieldName: (IdentifierInfo *)nullptr, DotLoc: DIE->getDesignator(Idx: DesigIdx)->getDotLoc(),
2454	FieldLoc: DIE->getDesignator(Idx: DesigIdx)->getFieldLoc()));
2455	else
2456	Replacements.push_back(Elt: Designator::CreateFieldDesignator(
2457	FieldName: (IdentifierInfo *)nullptr, DotLoc: SourceLocation(), FieldLoc: SourceLocation()));
2458	assert(isa<FieldDecl>(*PI));
2459	Replacements.back().setFieldDecl(cast<FieldDecl>(Val: *PI));
2460	}
2461
2462	// Expand the current designator into the set of replacement
2463	// designators, so we have a full subobject path down to where the
2464	// member of the anonymous struct/union is actually stored.
2465	DIE->ExpandDesignator(C: SemaRef.Context, Idx: DesigIdx, First: &Replacements[0],
2466	Last: &Replacements[0] + Replacements.size());
2467	}
2468
2469	static DesignatedInitExpr *CloneDesignatedInitExpr(Sema &SemaRef,
2470	DesignatedInitExpr *DIE) {
2471	unsigned NumIndexExprs = DIE->getNumSubExprs() - 1;
2472	SmallVector<Expr*, 4> IndexExprs(NumIndexExprs);
2473	for (unsigned I = 0; I < NumIndexExprs; ++I)
2474	IndexExprs[I] = DIE->getSubExpr(Idx: I + 1);
2475	return DesignatedInitExpr::Create(C: SemaRef.Context, Designators: DIE->designators(),
2476	IndexExprs,
2477	EqualOrColonLoc: DIE->getEqualOrColonLoc(),
2478	GNUSyntax: DIE->usesGNUSyntax(), Init: DIE->getInit());
2479	}
2480
2481	namespace {
2482
2483	// Callback to only accept typo corrections that are for field members of
2484	// the given struct or union.
2485	class FieldInitializerValidatorCCC final : public CorrectionCandidateCallback {
2486	public:
2487	explicit FieldInitializerValidatorCCC(const RecordDecl *RD)
2488	: Record(RD) {}
2489
2490	bool ValidateCandidate(const TypoCorrection &candidate) override {
2491	FieldDecl *FD = candidate.getCorrectionDeclAs<FieldDecl>();
2492	return FD && FD->getDeclContext()->getRedeclContext()->Equals(Record);
2493	}
2494
2495	std::unique_ptr<CorrectionCandidateCallback> clone() override {
2496	return std::make_unique<FieldInitializerValidatorCCC>(args&: *this);
2497	}
2498
2499	private:
2500	const RecordDecl *Record;
2501	};
2502
2503	} // end anonymous namespace
2504
2505	/// Check the well-formedness of a C99 designated initializer.
2506	///
2507	/// Determines whether the designated initializer @p DIE, which
2508	/// resides at the given @p Index within the initializer list @p
2509	/// IList, is well-formed for a current object of type @p DeclType
2510	/// (C99 6.7.8). The actual subobject that this designator refers to
2511	/// within the current subobject is returned in either
2512	/// @p NextField or @p NextElementIndex (whichever is appropriate).
2513	///
2514	/// @param IList The initializer list in which this designated
2515	/// initializer occurs.
2516	///
2517	/// @param DIE The designated initializer expression.
2518	///
2519	/// @param DesigIdx The index of the current designator.
2520	///
2521	/// @param CurrentObjectType The type of the "current object" (C99 6.7.8p17),
2522	/// into which the designation in @p DIE should refer.
2523	///
2524	/// @param NextField If non-NULL and the first designator in @p DIE is
2525	/// a field, this will be set to the field declaration corresponding
2526	/// to the field named by the designator. On input, this is expected to be
2527	/// the next field that would be initialized in the absence of designation,
2528	/// if the complete object being initialized is a struct.
2529	///
2530	/// @param NextElementIndex If non-NULL and the first designator in @p
2531	/// DIE is an array designator or GNU array-range designator, this
2532	/// will be set to the last index initialized by this designator.
2533	///
2534	/// @param Index Index into @p IList where the designated initializer
2535	/// @p DIE occurs.
2536	///
2537	/// @param StructuredList The initializer list expression that
2538	/// describes all of the subobject initializers in the order they'll
2539	/// actually be initialized.
2540	///
2541	/// @returns true if there was an error, false otherwise.
2542	bool
2543	InitListChecker::CheckDesignatedInitializer(const InitializedEntity &Entity,
2544	InitListExpr *IList,
2545	DesignatedInitExpr *DIE,
2546	unsigned DesigIdx,
2547	QualType &CurrentObjectType,
2548	RecordDecl::field_iterator *NextField,
2549	llvm::APSInt *NextElementIndex,
2550	unsigned &Index,
2551	InitListExpr *StructuredList,
2552	unsigned &StructuredIndex,
2553	bool FinishSubobjectInit,
2554	bool TopLevelObject) {
2555	if (DesigIdx == DIE->size()) {
2556	// C++20 designated initialization can result in direct-list-initialization
2557	// of the designated subobject. This is the only way that we can end up
2558	// performing direct initialization as part of aggregate initialization, so
2559	// it needs special handling.
2560	if (DIE->isDirectInit()) {
2561	Expr *Init = DIE->getInit();
2562	assert(isa<InitListExpr>(Init) &&
2563	"designator result in direct non-list initialization?");
2564	InitializationKind Kind = InitializationKind::CreateDirectList(
2565	DIE->getBeginLoc(), Init->getBeginLoc(), Init->getEndLoc());
2566	InitializationSequence Seq(SemaRef, Entity, Kind, Init,
2567	/*TopLevelOfInitList*/ true);
2568	if (StructuredList) {
2569	ExprResult Result = VerifyOnly
2570	? getDummyInit()
2571	: Seq.Perform(S&: SemaRef, Entity, Kind, Args: Init);
2572	UpdateStructuredListElement(StructuredList, StructuredIndex,
2573	expr: Result.get());
2574	}
2575	++Index;
2576	if (AggrDeductionCandidateParamTypes)
2577	AggrDeductionCandidateParamTypes->push_back(Elt: CurrentObjectType);
2578	return !Seq;
2579	}
2580
2581	// Check the actual initialization for the designated object type.
2582	bool prevHadError = hadError;
2583
2584	// Temporarily remove the designator expression from the
2585	// initializer list that the child calls see, so that we don't try
2586	// to re-process the designator.
2587	unsigned OldIndex = Index;
2588	IList->setInit(Init: OldIndex, expr: DIE->getInit());
2589
2590	CheckSubElementType(Entity, IList, ElemType: CurrentObjectType, Index, StructuredList,
2591	StructuredIndex, /*DirectlyDesignated=*/true);
2592
2593	// Restore the designated initializer expression in the syntactic
2594	// form of the initializer list.
2595	if (IList->getInit(Init: OldIndex) != DIE->getInit())
2596	DIE->setInit(IList->getInit(Init: OldIndex));
2597	IList->setInit(OldIndex, DIE);
2598
2599	return hadError && !prevHadError;
2600	}
2601
2602	DesignatedInitExpr::Designator *D = DIE->getDesignator(Idx: DesigIdx);
2603	bool IsFirstDesignator = (DesigIdx == 0);
2604	if (IsFirstDesignator ? FullyStructuredList : StructuredList) {
2605	// Determine the structural initializer list that corresponds to the
2606	// current subobject.
2607	if (IsFirstDesignator)
2608	StructuredList = FullyStructuredList;
2609	else {
2610	Expr *ExistingInit = StructuredIndex < StructuredList->getNumInits() ?
2611	StructuredList->getInit(Init: StructuredIndex) : nullptr;
2612	if (!ExistingInit && StructuredList->hasArrayFiller())
2613	ExistingInit = StructuredList->getArrayFiller();
2614
2615	if (!ExistingInit)
2616	StructuredList = getStructuredSubobjectInit(
2617	IList, Index, CurrentObjectType, StructuredList, StructuredIndex,
2618	InitRange: SourceRange(D->getBeginLoc(), DIE->getEndLoc()));
2619	else if (InitListExpr *Result = dyn_cast<InitListExpr>(Val: ExistingInit))
2620	StructuredList = Result;
2621	else {
2622	// We are creating an initializer list that initializes the
2623	// subobjects of the current object, but there was already an
2624	// initialization that completely initialized the current
2625	// subobject, e.g., by a compound literal:
2626	//
2627	// struct X { int a, b; };
2628	// struct X xs[] = { [0] = (struct X) { 1, 2 }, [0].b = 3 };
2629	//
2630	// Here, xs[0].a == 1 and xs[0].b == 3, since the second,
2631	// designated initializer re-initializes only its current object
2632	// subobject [0].b.
2633	diagnoseInitOverride(OldInit: ExistingInit,
2634	NewInitRange: SourceRange(D->getBeginLoc(), DIE->getEndLoc()),
2635	/*UnionOverride=*/false,
2636	/*FullyOverwritten=*/false);
2637
2638	if (!VerifyOnly) {
2639	if (DesignatedInitUpdateExpr *E =
2640	dyn_cast<DesignatedInitUpdateExpr>(Val: ExistingInit))
2641	StructuredList = E->getUpdater();
2642	else {
2643	DesignatedInitUpdateExpr *DIUE = new (SemaRef.Context)
2644	DesignatedInitUpdateExpr(SemaRef.Context, D->getBeginLoc(),
2645	ExistingInit, DIE->getEndLoc());
2646	StructuredList->updateInit(SemaRef.Context, StructuredIndex, DIUE);
2647	StructuredList = DIUE->getUpdater();
2648	}
2649	} else {
2650	// We don't need to track the structured representation of a
2651	// designated init update of an already-fully-initialized object in
2652	// verify-only mode. The only reason we would need the structure is
2653	// to determine where the uninitialized "holes" are, and in this
2654	// case, we know there aren't any and we can't introduce any.
2655	StructuredList = nullptr;
2656	}
2657	}
2658	}
2659	}
2660
2661	if (D->isFieldDesignator()) {
2662	// C99 6.7.8p7:
2663	//
2664	// If a designator has the form
2665	//
2666	// . identifier
2667	//
2668	// then the current object (defined below) shall have
2669	// structure or union type and the identifier shall be the
2670	// name of a member of that type.
2671	RecordDecl *RD = getRecordDecl(DeclType: CurrentObjectType);
2672	if (!RD) {
2673	SourceLocation Loc = D->getDotLoc();
2674	if (Loc.isInvalid())
2675	Loc = D->getFieldLoc();
2676	if (!VerifyOnly)
2677	SemaRef.Diag(Loc, diag::err_field_designator_non_aggr)
2678	<< SemaRef.getLangOpts().CPlusPlus << CurrentObjectType;
2679	++Index;
2680	return true;
2681	}
2682
2683	FieldDecl *KnownField = D->getFieldDecl();
2684	if (!KnownField) {
2685	const IdentifierInfo *FieldName = D->getFieldName();
2686	ValueDecl *VD = SemaRef.tryLookupUnambiguousFieldDecl(ClassDecl: RD, MemberOrBase: FieldName);
2687	if (auto *FD = dyn_cast_if_present<FieldDecl>(Val: VD)) {
2688	KnownField = FD;
2689	} else if (auto *IFD = dyn_cast_if_present<IndirectFieldDecl>(Val: VD)) {
2690	// In verify mode, don't modify the original.
2691	if (VerifyOnly)
2692	DIE = CloneDesignatedInitExpr(SemaRef, DIE);
2693	ExpandAnonymousFieldDesignator(SemaRef, DIE, DesigIdx, IndirectField: IFD);
2694	D = DIE->getDesignator(Idx: DesigIdx);
2695	KnownField = cast<FieldDecl>(Val: *IFD->chain_begin());
2696	}
2697	if (!KnownField) {
2698	if (VerifyOnly) {
2699	++Index;
2700	return true; // No typo correction when just trying this out.
2701	}
2702
2703	// We found a placeholder variable
2704	if (SemaRef.DiagRedefinedPlaceholderFieldDecl(Loc: DIE->getBeginLoc(), ClassDecl: RD,
2705	Name: FieldName)) {
2706	++Index;
2707	return true;
2708	}
2709	// Name lookup found something, but it wasn't a field.
2710	if (DeclContextLookupResult Lookup = RD->lookup(FieldName);
2711	!Lookup.empty()) {
2712	SemaRef.Diag(D->getFieldLoc(), diag::err_field_designator_nonfield)
2713	<< FieldName;
2714	SemaRef.Diag(Lookup.front()->getLocation(),
2715	diag::note_field_designator_found);
2716	++Index;
2717	return true;
2718	}
2719
2720	// Name lookup didn't find anything.
2721	// Determine whether this was a typo for another field name.
2722	FieldInitializerValidatorCCC CCC(RD);
2723	if (TypoCorrection Corrected = SemaRef.CorrectTypo(
2724	DeclarationNameInfo(FieldName, D->getFieldLoc()),
2725	Sema::LookupMemberName, /*Scope=*/nullptr, /*SS=*/nullptr, CCC,
2726	Sema::CTK_ErrorRecovery, RD)) {
2727	SemaRef.diagnoseTypo(
2728	Corrected,
2729	SemaRef.PDiag(diag::err_field_designator_unknown_suggest)
2730	<< FieldName << CurrentObjectType);
2731	KnownField = Corrected.getCorrectionDeclAs<FieldDecl>();
2732	hadError = true;
2733	} else {
2734	// Typo correction didn't find anything.
2735	SourceLocation Loc = D->getFieldLoc();
2736
2737	// The loc can be invalid with a "null" designator (i.e. an anonymous
2738	// union/struct). Do our best to approximate the location.
2739	if (Loc.isInvalid())
2740	Loc = IList->getBeginLoc();
2741
2742	SemaRef.Diag(Loc, diag::err_field_designator_unknown)
2743	<< FieldName << CurrentObjectType << DIE->getSourceRange();
2744	++Index;
2745	return true;
2746	}
2747	}
2748	}
2749
2750	unsigned NumBases = 0;
2751	if (auto *CXXRD = dyn_cast<CXXRecordDecl>(Val: RD))
2752	NumBases = CXXRD->getNumBases();
2753
2754	unsigned FieldIndex = NumBases;
2755
2756	for (auto *FI : RD->fields()) {
2757	if (FI->isUnnamedBitfield())
2758	continue;
2759	if (declaresSameEntity(KnownField, FI)) {
2760	KnownField = FI;
2761	break;
2762	}
2763	++FieldIndex;
2764	}
2765
2766	RecordDecl::field_iterator Field =
2767	RecordDecl::field_iterator(DeclContext::decl_iterator(KnownField));
2768
2769	// All of the fields of a union are located at the same place in
2770	// the initializer list.
2771	if (RD->isUnion()) {
2772	FieldIndex = 0;
2773	if (StructuredList) {
2774	FieldDecl *CurrentField = StructuredList->getInitializedFieldInUnion();
2775	if (CurrentField && !declaresSameEntity(CurrentField, *Field)) {
2776	assert(StructuredList->getNumInits() == 1
2777	&& "A union should never have more than one initializer!");
2778
2779	Expr *ExistingInit = StructuredList->getInit(Init: 0);
2780	if (ExistingInit) {
2781	// We're about to throw away an initializer, emit warning.
2782	diagnoseInitOverride(
2783	OldInit: ExistingInit, NewInitRange: SourceRange(D->getBeginLoc(), DIE->getEndLoc()),
2784	/*UnionOverride=*/true,
2785	/*FullyOverwritten=*/SemaRef.getLangOpts().CPlusPlus ? false
2786	: true);
2787	}
2788
2789	// remove existing initializer
2790	StructuredList->resizeInits(Context: SemaRef.Context, NumInits: 0);
2791	StructuredList->setInitializedFieldInUnion(nullptr);
2792	}
2793
2794	StructuredList->setInitializedFieldInUnion(*Field);
2795	}
2796	}
2797
2798	// Make sure we can use this declaration.
2799	bool InvalidUse;
2800	if (VerifyOnly)
2801	InvalidUse = !SemaRef.CanUseDecl(*Field, TreatUnavailableAsInvalid);
2802	else
2803	InvalidUse = SemaRef.DiagnoseUseOfDecl(*Field, D->getFieldLoc());
2804	if (InvalidUse) {
2805	++Index;
2806	return true;
2807	}
2808
2809	// C++20 [dcl.init.list]p3:
2810	// The ordered identifiers in the designators of the designated-
2811	// initializer-list shall form a subsequence of the ordered identifiers
2812	// in the direct non-static data members of T.
2813	//
2814	// Note that this is not a condition on forming the aggregate
2815	// initialization, only on actually performing initialization,
2816	// so it is not checked in VerifyOnly mode.
2817	//
2818	// FIXME: This is the only reordering diagnostic we produce, and it only
2819	// catches cases where we have a top-level field designator that jumps
2820	// backwards. This is the only such case that is reachable in an
2821	// otherwise-valid C++20 program, so is the only case that's required for
2822	// conformance, but for consistency, we should diagnose all the other
2823	// cases where a designator takes us backwards too.
2824	if (IsFirstDesignator && !VerifyOnly && SemaRef.getLangOpts().CPlusPlus &&
2825	NextField &&
2826	(*NextField == RD->field_end() ||
2827	(*NextField)->getFieldIndex() > Field->getFieldIndex() + 1)) {
2828	// Find the field that we just initialized.
2829	FieldDecl *PrevField = nullptr;
2830	for (auto FI = RD->field_begin(); FI != RD->field_end(); ++FI) {
2831	if (FI->isUnnamedBitfield())
2832	continue;
2833	if (*NextField != RD->field_end() &&
2834	declaresSameEntity(*FI, **NextField))
2835	break;
2836	PrevField = *FI;
2837	}
2838
2839	if (PrevField &&
2840	PrevField->getFieldIndex() > KnownField->getFieldIndex()) {
2841	SemaRef.Diag(DIE->getInit()->getBeginLoc(),
2842	diag::ext_designated_init_reordered)
2843	<< KnownField << PrevField << DIE->getSourceRange();
2844
2845	unsigned OldIndex = StructuredIndex - 1;
2846	if (StructuredList && OldIndex <= StructuredList->getNumInits()) {
2847	if (Expr *PrevInit = StructuredList->getInit(Init: OldIndex)) {
2848	SemaRef.Diag(PrevInit->getBeginLoc(),
2849	diag::note_previous_field_init)
2850	<< PrevField << PrevInit->getSourceRange();
2851	}
2852	}
2853	}
2854	}
2855
2856
2857	// Update the designator with the field declaration.
2858	if (!VerifyOnly)
2859	D->setFieldDecl(*Field);
2860
2861	// Make sure that our non-designated initializer list has space
2862	// for a subobject corresponding to this field.
2863	if (StructuredList && FieldIndex >= StructuredList->getNumInits())
2864	StructuredList->resizeInits(Context: SemaRef.Context, NumInits: FieldIndex + 1);
2865
2866	// This designator names a flexible array member.
2867	if (Field->getType()->isIncompleteArrayType()) {
2868	bool Invalid = false;
2869	if ((DesigIdx + 1) != DIE->size()) {
2870	// We can't designate an object within the flexible array
2871	// member (because GCC doesn't allow it).
2872	if (!VerifyOnly) {
2873	DesignatedInitExpr::Designator *NextD
2874	= DIE->getDesignator(Idx: DesigIdx + 1);
2875	SemaRef.Diag(NextD->getBeginLoc(),
2876	diag::err_designator_into_flexible_array_member)
2877	<< SourceRange(NextD->getBeginLoc(), DIE->getEndLoc());
2878	SemaRef.Diag(Field->getLocation(), diag::note_flexible_array_member)
2879	<< *Field;
2880	}
2881	Invalid = true;
2882	}
2883
2884	if (!hadError && !isa<InitListExpr>(Val: DIE->getInit()) &&
2885	!isa<StringLiteral>(Val: DIE->getInit())) {
2886	// The initializer is not an initializer list.
2887	if (!VerifyOnly) {
2888	SemaRef.Diag(DIE->getInit()->getBeginLoc(),
2889	diag::err_flexible_array_init_needs_braces)
2890	<< DIE->getInit()->getSourceRange();
2891	SemaRef.Diag(Field->getLocation(), diag::note_flexible_array_member)
2892	<< *Field;
2893	}
2894	Invalid = true;
2895	}
2896
2897	// Check GNU flexible array initializer.
2898	if (!Invalid && CheckFlexibleArrayInit(Entity, InitExpr: DIE->getInit(), Field: *Field,
2899	TopLevelObject))
2900	Invalid = true;
2901
2902	if (Invalid) {
2903	++Index;
2904	return true;
2905	}
2906
2907	// Initialize the array.
2908	bool prevHadError = hadError;
2909	unsigned newStructuredIndex = FieldIndex;
2910	unsigned OldIndex = Index;
2911	IList->setInit(Init: Index, expr: DIE->getInit());
2912
2913	InitializedEntity MemberEntity =
2914	InitializedEntity::InitializeMember(Member: *Field, Parent: &Entity);
2915	CheckSubElementType(Entity: MemberEntity, IList, ElemType: Field->getType(), Index,
2916	StructuredList, StructuredIndex&: newStructuredIndex);
2917
2918	IList->setInit(OldIndex, DIE);
2919	if (hadError && !prevHadError) {
2920	++Field;
2921	++FieldIndex;
2922	if (NextField)
2923	*NextField = Field;
2924	StructuredIndex = FieldIndex;
2925	return true;
2926	}
2927	} else {
2928	// Recurse to check later designated subobjects.
2929	QualType FieldType = Field->getType();
2930	unsigned newStructuredIndex = FieldIndex;
2931
2932	InitializedEntity MemberEntity =
2933	InitializedEntity::InitializeMember(Member: *Field, Parent: &Entity);
2934	if (CheckDesignatedInitializer(Entity: MemberEntity, IList, DIE, DesigIdx: DesigIdx + 1,
2935	CurrentObjectType&: FieldType, NextField: nullptr, NextElementIndex: nullptr, Index,
2936	StructuredList, StructuredIndex&: newStructuredIndex,
2937	FinishSubobjectInit, TopLevelObject: false))
2938	return true;
2939	}
2940
2941	// Find the position of the next field to be initialized in this
2942	// subobject.
2943	++Field;
2944	++FieldIndex;
2945
2946	// If this the first designator, our caller will continue checking
2947	// the rest of this struct/class/union subobject.
2948	if (IsFirstDesignator) {
2949	if (Field != RD->field_end() && Field->isUnnamedBitfield())
2950	++Field;
2951
2952	if (NextField)
2953	*NextField = Field;
2954
2955	StructuredIndex = FieldIndex;
2956	return false;
2957	}
2958
2959	if (!FinishSubobjectInit)
2960	return false;
2961
2962	// We've already initialized something in the union; we're done.
2963	if (RD->isUnion())
2964	return hadError;
2965
2966	// Check the remaining fields within this class/struct/union subobject.
2967	bool prevHadError = hadError;
2968
2969	auto NoBases =
2970	CXXRecordDecl::base_class_range(CXXRecordDecl::base_class_iterator(),
2971	CXXRecordDecl::base_class_iterator());
2972	CheckStructUnionTypes(Entity, IList, DeclType: CurrentObjectType, Bases: NoBases, Field,
2973	SubobjectIsDesignatorContext: false, Index, StructuredList, StructuredIndex&: FieldIndex);
2974	return hadError && !prevHadError;
2975	}
2976
2977	// C99 6.7.8p6:
2978	//
2979	// If a designator has the form
2980	//
2981	// [ constant-expression ]
2982	//
2983	// then the current object (defined below) shall have array
2984	// type and the expression shall be an integer constant
2985	// expression. If the array is of unknown size, any
2986	// nonnegative value is valid.
2987	//
2988	// Additionally, cope with the GNU extension that permits
2989	// designators of the form
2990	//
2991	// [ constant-expression ... constant-expression ]
2992	const ArrayType *AT = SemaRef.Context.getAsArrayType(T: CurrentObjectType);
2993	if (!AT) {
2994	if (!VerifyOnly)
2995	SemaRef.Diag(D->getLBracketLoc(), diag::err_array_designator_non_array)
2996	<< CurrentObjectType;
2997	++Index;
2998	return true;
2999	}
3000
3001	Expr *IndexExpr = nullptr;
3002	llvm::APSInt DesignatedStartIndex, DesignatedEndIndex;
3003	if (D->isArrayDesignator()) {
3004	IndexExpr = DIE->getArrayIndex(D: *D);
3005	DesignatedStartIndex = IndexExpr->EvaluateKnownConstInt(Ctx: SemaRef.Context);
3006	DesignatedEndIndex = DesignatedStartIndex;
3007	} else {
3008	assert(D->isArrayRangeDesignator() && "Need array-range designator");
3009
3010	DesignatedStartIndex =
3011	DIE->getArrayRangeStart(D: *D)->EvaluateKnownConstInt(Ctx: SemaRef.Context);
3012	DesignatedEndIndex =
3013	DIE->getArrayRangeEnd(D: *D)->EvaluateKnownConstInt(Ctx: SemaRef.Context);
3014	IndexExpr = DIE->getArrayRangeEnd(D: *D);
3015
3016	// Codegen can't handle evaluating array range designators that have side
3017	// effects, because we replicate the AST value for each initialized element.
3018	// As such, set the sawArrayRangeDesignator() bit if we initialize multiple
3019	// elements with something that has a side effect, so codegen can emit an
3020	// "error unsupported" error instead of miscompiling the app.
3021	if (DesignatedStartIndex.getZExtValue()!=DesignatedEndIndex.getZExtValue()&&
3022	DIE->getInit()->HasSideEffects(Ctx: SemaRef.Context) && !VerifyOnly)
3023	FullyStructuredList->sawArrayRangeDesignator();
3024	}
3025
3026	if (isa<ConstantArrayType>(Val: AT)) {
3027	llvm::APSInt MaxElements(cast<ConstantArrayType>(Val: AT)->getSize(), false);
3028	DesignatedStartIndex
3029	= DesignatedStartIndex.extOrTrunc(width: MaxElements.getBitWidth());
3030	DesignatedStartIndex.setIsUnsigned(MaxElements.isUnsigned());
3031	DesignatedEndIndex
3032	= DesignatedEndIndex.extOrTrunc(width: MaxElements.getBitWidth());
3033	DesignatedEndIndex.setIsUnsigned(MaxElements.isUnsigned());
3034	if (DesignatedEndIndex >= MaxElements) {
3035	if (!VerifyOnly)
3036	SemaRef.Diag(IndexExpr->getBeginLoc(),
3037	diag::err_array_designator_too_large)
3038	<< toString(DesignatedEndIndex, 10) << toString(MaxElements, 10)
3039	<< IndexExpr->getSourceRange();
3040	++Index;
3041	return true;
3042	}
3043	} else {
3044	unsigned DesignatedIndexBitWidth =
3045	ConstantArrayType::getMaxSizeBits(Context: SemaRef.Context);
3046	DesignatedStartIndex =
3047	DesignatedStartIndex.extOrTrunc(width: DesignatedIndexBitWidth);
3048	DesignatedEndIndex =
3049	DesignatedEndIndex.extOrTrunc(width: DesignatedIndexBitWidth);
3050	DesignatedStartIndex.setIsUnsigned(true);
3051	DesignatedEndIndex.setIsUnsigned(true);
3052	}
3053
3054	bool IsStringLiteralInitUpdate =
3055	StructuredList && StructuredList->isStringLiteralInit();
3056	if (IsStringLiteralInitUpdate && VerifyOnly) {
3057	// We're just verifying an update to a string literal init. We don't need
3058	// to split the string up into individual characters to do that.
3059	StructuredList = nullptr;
3060	} else if (IsStringLiteralInitUpdate) {
3061	// We're modifying a string literal init; we have to decompose the string
3062	// so we can modify the individual characters.
3063	ASTContext &Context = SemaRef.Context;
3064	Expr *SubExpr = StructuredList->getInit(Init: 0)->IgnoreParenImpCasts();
3065
3066	// Compute the character type
3067	QualType CharTy = AT->getElementType();
3068
3069	// Compute the type of the integer literals.
3070	QualType PromotedCharTy = CharTy;
3071	if (Context.isPromotableIntegerType(T: CharTy))
3072	PromotedCharTy = Context.getPromotedIntegerType(PromotableType: CharTy);
3073	unsigned PromotedCharTyWidth = Context.getTypeSize(T: PromotedCharTy);
3074
3075	if (StringLiteral *SL = dyn_cast<StringLiteral>(Val: SubExpr)) {
3076	// Get the length of the string.
3077	uint64_t StrLen = SL->getLength();
3078	if (cast<ConstantArrayType>(Val: AT)->getSize().ult(RHS: StrLen))
3079	StrLen = cast<ConstantArrayType>(Val: AT)->getSize().getZExtValue();
3080	StructuredList->resizeInits(Context, NumInits: StrLen);
3081
3082	// Build a literal for each character in the string, and put them into
3083	// the init list.
3084	for (unsigned i = 0, e = StrLen; i != e; ++i) {
3085	llvm::APInt CodeUnit(PromotedCharTyWidth, SL->getCodeUnit(i));
3086	Expr *Init = new (Context) IntegerLiteral(
3087	Context, CodeUnit, PromotedCharTy, SubExpr->getExprLoc());
3088	if (CharTy != PromotedCharTy)
3089	Init = ImplicitCastExpr::Create(Context, T: CharTy, Kind: CK_IntegralCast,
3090	Operand: Init, BasePath: nullptr, Cat: VK_PRValue,
3091	FPO: FPOptionsOverride());
3092	StructuredList->updateInit(C: Context, Init: i, expr: Init);
3093	}
3094	} else {
3095	ObjCEncodeExpr *E = cast<ObjCEncodeExpr>(Val: SubExpr);
3096	std::string Str;
3097	Context.getObjCEncodingForType(T: E->getEncodedType(), S&: Str);
3098
3099	// Get the length of the string.
3100	uint64_t StrLen = Str.size();
3101	if (cast<ConstantArrayType>(Val: AT)->getSize().ult(RHS: StrLen))
3102	StrLen = cast<ConstantArrayType>(Val: AT)->getSize().getZExtValue();
3103	StructuredList->resizeInits(Context, NumInits: StrLen);
3104
3105	// Build a literal for each character in the string, and put them into
3106	// the init list.
3107	for (unsigned i = 0, e = StrLen; i != e; ++i) {
3108	llvm::APInt CodeUnit(PromotedCharTyWidth, Str[i]);
3109	Expr *Init = new (Context) IntegerLiteral(
3110	Context, CodeUnit, PromotedCharTy, SubExpr->getExprLoc());
3111	if (CharTy != PromotedCharTy)
3112	Init = ImplicitCastExpr::Create(Context, T: CharTy, Kind: CK_IntegralCast,
3113	Operand: Init, BasePath: nullptr, Cat: VK_PRValue,
3114	FPO: FPOptionsOverride());
3115	StructuredList->updateInit(C: Context, Init: i, expr: Init);
3116	}
3117	}
3118	}
3119
3120	// Make sure that our non-designated initializer list has space
3121	// for a subobject corresponding to this array element.
3122	if (StructuredList &&
3123	DesignatedEndIndex.getZExtValue() >= StructuredList->getNumInits())
3124	StructuredList->resizeInits(Context: SemaRef.Context,
3125	NumInits: DesignatedEndIndex.getZExtValue() + 1);
3126
3127	// Repeatedly perform subobject initializations in the range
3128	// [DesignatedStartIndex, DesignatedEndIndex].
3129
3130	// Move to the next designator
3131	unsigned ElementIndex = DesignatedStartIndex.getZExtValue();
3132	unsigned OldIndex = Index;
3133
3134	InitializedEntity ElementEntity =
3135	InitializedEntity::InitializeElement(Context&: SemaRef.Context, Index: 0, Parent: Entity);
3136
3137	while (DesignatedStartIndex <= DesignatedEndIndex) {
3138	// Recurse to check later designated subobjects.
3139	QualType ElementType = AT->getElementType();
3140	Index = OldIndex;
3141
3142	ElementEntity.setElementIndex(ElementIndex);
3143	if (CheckDesignatedInitializer(
3144	Entity: ElementEntity, IList, DIE, DesigIdx: DesigIdx + 1, CurrentObjectType&: ElementType, NextField: nullptr,
3145	NextElementIndex: nullptr, Index, StructuredList, StructuredIndex&: ElementIndex,
3146	FinishSubobjectInit: FinishSubobjectInit && (DesignatedStartIndex == DesignatedEndIndex),
3147	TopLevelObject: false))
3148	return true;
3149
3150	// Move to the next index in the array that we'll be initializing.
3151	++DesignatedStartIndex;
3152	ElementIndex = DesignatedStartIndex.getZExtValue();
3153	}
3154
3155	// If this the first designator, our caller will continue checking
3156	// the rest of this array subobject.
3157	if (IsFirstDesignator) {
3158	if (NextElementIndex)
3159	*NextElementIndex = DesignatedStartIndex;
3160	StructuredIndex = ElementIndex;
3161	return false;
3162	}
3163
3164	if (!FinishSubobjectInit)
3165	return false;
3166
3167	// Check the remaining elements within this array subobject.
3168	bool prevHadError = hadError;
3169	CheckArrayType(Entity, IList, DeclType&: CurrentObjectType, elementIndex: DesignatedStartIndex,
3170	/*SubobjectIsDesignatorContext=*/false, Index,
3171	StructuredList, StructuredIndex&: ElementIndex);
3172	return hadError && !prevHadError;
3173	}
3174
3175	// Get the structured initializer list for a subobject of type
3176	// @p CurrentObjectType.
3177	InitListExpr *
3178	InitListChecker::getStructuredSubobjectInit(InitListExpr *IList, unsigned Index,
3179	QualType CurrentObjectType,
3180	InitListExpr *StructuredList,
3181	unsigned StructuredIndex,
3182	SourceRange InitRange,
3183	bool IsFullyOverwritten) {
3184	if (!StructuredList)
3185	return nullptr;
3186
3187	Expr *ExistingInit = nullptr;
3188	if (StructuredIndex < StructuredList->getNumInits())
3189	ExistingInit = StructuredList->getInit(Init: StructuredIndex);
3190
3191	if (InitListExpr *Result = dyn_cast_or_null<InitListExpr>(Val: ExistingInit))
3192	// There might have already been initializers for subobjects of the current
3193	// object, but a subsequent initializer list will overwrite the entirety
3194	// of the current object. (See DR 253 and C99 6.7.8p21). e.g.,
3195	//
3196	// struct P { char x[6]; };
3197	// struct P l = { .x[2] = 'x', .x = { [0] = 'f' } };
3198	//
3199	// The first designated initializer is ignored, and l.x is just "f".
3200	if (!IsFullyOverwritten)
3201	return Result;
3202
3203	if (ExistingInit) {
3204	// We are creating an initializer list that initializes the
3205	// subobjects of the current object, but there was already an
3206	// initialization that completely initialized the current
3207	// subobject:
3208	//
3209	// struct X { int a, b; };
3210	// struct X xs[] = { [0] = { 1, 2 }, [0].b = 3 };
3211	//
3212	// Here, xs[0].a == 1 and xs[0].b == 3, since the second,
3213	// designated initializer overwrites the [0].b initializer
3214	// from the prior initialization.
3215	//
3216	// When the existing initializer is an expression rather than an
3217	// initializer list, we cannot decompose and update it in this way.
3218	// For example:
3219	//
3220	// struct X xs[] = { [0] = (struct X) { 1, 2 }, [0].b = 3 };
3221	//
3222	// This case is handled by CheckDesignatedInitializer.
3223	diagnoseInitOverride(OldInit: ExistingInit, NewInitRange: InitRange);
3224	}
3225
3226	unsigned ExpectedNumInits = 0;
3227	if (Index < IList->getNumInits()) {
3228	if (auto *Init = dyn_cast_or_null<InitListExpr>(Val: IList->getInit(Init: Index)))
3229	ExpectedNumInits = Init->getNumInits();
3230	else
3231	ExpectedNumInits = IList->getNumInits() - Index;
3232	}
3233
3234	InitListExpr *Result =
3235	createInitListExpr(CurrentObjectType, InitRange, ExpectedNumInits);
3236
3237	// Link this new initializer list into the structured initializer
3238	// lists.
3239	StructuredList->updateInit(SemaRef.Context, StructuredIndex, Result);
3240	return Result;
3241	}
3242
3243	InitListExpr *
3244	InitListChecker::createInitListExpr(QualType CurrentObjectType,
3245	SourceRange InitRange,
3246	unsigned ExpectedNumInits) {
3247	InitListExpr *Result = new (SemaRef.Context) InitListExpr(
3248	SemaRef.Context, InitRange.getBegin(), std::nullopt, InitRange.getEnd());
3249
3250	QualType ResultType = CurrentObjectType;
3251	if (!ResultType->isArrayType())
3252	ResultType = ResultType.getNonLValueExprType(Context: SemaRef.Context);
3253	Result->setType(ResultType);
3254
3255	// Pre-allocate storage for the structured initializer list.
3256	unsigned NumElements = 0;
3257
3258	if (const ArrayType *AType
3259	= SemaRef.Context.getAsArrayType(T: CurrentObjectType)) {
3260	if (const ConstantArrayType *CAType = dyn_cast<ConstantArrayType>(Val: AType)) {
3261	NumElements = CAType->getSize().getZExtValue();
3262	// Simple heuristic so that we don't allocate a very large
3263	// initializer with many empty entries at the end.
3264	if (NumElements > ExpectedNumInits)
3265	NumElements = 0;
3266	}
3267	} else if (const VectorType *VType = CurrentObjectType->getAs<VectorType>()) {
3268	NumElements = VType->getNumElements();
3269	} else if (CurrentObjectType->isRecordType()) {
3270	NumElements = numStructUnionElements(DeclType: CurrentObjectType);
3271	} else if (CurrentObjectType->isDependentType()) {
3272	NumElements = 1;
3273	}
3274
3275	Result->reserveInits(C: SemaRef.Context, NumInits: NumElements);
3276
3277	return Result;
3278	}
3279
3280	/// Update the initializer at index @p StructuredIndex within the
3281	/// structured initializer list to the value @p expr.
3282	void InitListChecker::UpdateStructuredListElement(InitListExpr *StructuredList,
3283	unsigned &StructuredIndex,
3284	Expr *expr) {
3285	// No structured initializer list to update
3286	if (!StructuredList)
3287	return;
3288
3289	if (Expr *PrevInit = StructuredList->updateInit(C: SemaRef.Context,
3290	Init: StructuredIndex, expr)) {
3291	// This initializer overwrites a previous initializer.
3292	// No need to diagnose when `expr` is nullptr because a more relevant
3293	// diagnostic has already been issued and this diagnostic is potentially
3294	// noise.
3295	if (expr)
3296	diagnoseInitOverride(OldInit: PrevInit, NewInitRange: expr->getSourceRange());
3297	}
3298
3299	++StructuredIndex;
3300	}
3301
3302	/// Determine whether we can perform aggregate initialization for the purposes
3303	/// of overload resolution.
3304	bool Sema::CanPerformAggregateInitializationForOverloadResolution(
3305	const InitializedEntity &Entity, InitListExpr *From) {
3306	QualType Type = Entity.getType();
3307	InitListChecker Check(*this, Entity, From, Type, /*VerifyOnly=*/true,
3308	/*TreatUnavailableAsInvalid=*/false,
3309	/*InOverloadResolution=*/true);
3310	return !Check.HadError();
3311	}
3312
3313	/// Check that the given Index expression is a valid array designator
3314	/// value. This is essentially just a wrapper around
3315	/// VerifyIntegerConstantExpression that also checks for negative values
3316	/// and produces a reasonable diagnostic if there is a
3317	/// failure. Returns the index expression, possibly with an implicit cast
3318	/// added, on success. If everything went okay, Value will receive the
3319	/// value of the constant expression.
3320	static ExprResult
3321	CheckArrayDesignatorExpr(Sema &S, Expr *Index, llvm::APSInt &Value) {
3322	SourceLocation Loc = Index->getBeginLoc();
3323
3324	// Make sure this is an integer constant expression.
3325	ExprResult Result =
3326	S.VerifyIntegerConstantExpression(E: Index, Result: &Value, CanFold: Sema::AllowFold);
3327	if (Result.isInvalid())
3328	return Result;
3329
3330	if (Value.isSigned() && Value.isNegative())
3331	return S.Diag(Loc, diag::err_array_designator_negative)
3332	<< toString(Value, 10) << Index->getSourceRange();
3333
3334	Value.setIsUnsigned(true);
3335	return Result;
3336	}
3337
3338	ExprResult Sema::ActOnDesignatedInitializer(Designation &Desig,
3339	SourceLocation EqualOrColonLoc,
3340	bool GNUSyntax,
3341	ExprResult Init) {
3342	typedef DesignatedInitExpr::Designator ASTDesignator;
3343
3344	bool Invalid = false;
3345	SmallVector<ASTDesignator, 32> Designators;
3346	SmallVector<Expr *, 32> InitExpressions;
3347
3348	// Build designators and check array designator expressions.
3349	for (unsigned Idx = 0; Idx < Desig.getNumDesignators(); ++Idx) {
3350	const Designator &D = Desig.getDesignator(Idx);
3351
3352	if (D.isFieldDesignator()) {
3353	Designators.push_back(Elt: ASTDesignator::CreateFieldDesignator(
3354	FieldName: D.getFieldDecl(), DotLoc: D.getDotLoc(), FieldLoc: D.getFieldLoc()));
3355	} else if (D.isArrayDesignator()) {
3356	Expr *Index = static_cast<Expr *>(D.getArrayIndex());
3357	llvm::APSInt IndexValue;
3358	if (!Index->isTypeDependent() && !Index->isValueDependent())
3359	Index = CheckArrayDesignatorExpr(S&: *this, Index, Value&: IndexValue).get();
3360	if (!Index)
3361	Invalid = true;
3362	else {
3363	Designators.push_back(Elt: ASTDesignator::CreateArrayDesignator(
3364	Index: InitExpressions.size(), LBracketLoc: D.getLBracketLoc(), RBracketLoc: D.getRBracketLoc()));
3365	InitExpressions.push_back(Elt: Index);
3366	}
3367	} else if (D.isArrayRangeDesignator()) {
3368	Expr *StartIndex = static_cast<Expr *>(D.getArrayRangeStart());
3369	Expr *EndIndex = static_cast<Expr *>(D.getArrayRangeEnd());
3370	llvm::APSInt StartValue;
3371	llvm::APSInt EndValue;
3372	bool StartDependent = StartIndex->isTypeDependent() ||
3373	StartIndex->isValueDependent();
3374	bool EndDependent = EndIndex->isTypeDependent() ||
3375	EndIndex->isValueDependent();
3376	if (!StartDependent)
3377	StartIndex =
3378	CheckArrayDesignatorExpr(S&: *this, Index: StartIndex, Value&: StartValue).get();
3379	if (!EndDependent)
3380	EndIndex = CheckArrayDesignatorExpr(S&: *this, Index: EndIndex, Value&: EndValue).get();
3381
3382	if (!StartIndex || !EndIndex)
3383	Invalid = true;
3384	else {
3385	// Make sure we're comparing values with the same bit width.
3386	if (StartDependent || EndDependent) {
3387	// Nothing to compute.
3388	} else if (StartValue.getBitWidth() > EndValue.getBitWidth())
3389	EndValue = EndValue.extend(width: StartValue.getBitWidth());
3390	else if (StartValue.getBitWidth() < EndValue.getBitWidth())
3391	StartValue = StartValue.extend(width: EndValue.getBitWidth());
3392
3393	if (!StartDependent && !EndDependent && EndValue < StartValue) {
3394	Diag(D.getEllipsisLoc(), diag::err_array_designator_empty_range)
3395	<< toString(StartValue, 10) << toString(EndValue, 10)
3396	<< StartIndex->getSourceRange() << EndIndex->getSourceRange();
3397	Invalid = true;
3398	} else {
3399	Designators.push_back(Elt: ASTDesignator::CreateArrayRangeDesignator(
3400	Index: InitExpressions.size(), LBracketLoc: D.getLBracketLoc(), EllipsisLoc: D.getEllipsisLoc(),
3401	RBracketLoc: D.getRBracketLoc()));
3402	InitExpressions.push_back(Elt: StartIndex);
3403	InitExpressions.push_back(Elt: EndIndex);
3404	}
3405	}
3406	}
3407	}
3408
3409	if (Invalid || Init.isInvalid())
3410	return ExprError();
3411
3412	return DesignatedInitExpr::Create(C: Context, Designators, IndexExprs: InitExpressions,
3413	EqualOrColonLoc, GNUSyntax,
3414	Init: Init.getAs<Expr>());
3415	}
3416
3417	//===----------------------------------------------------------------------===//
3418	// Initialization entity
3419	//===----------------------------------------------------------------------===//
3420
3421	InitializedEntity::InitializedEntity(ASTContext &Context, unsigned Index,
3422	const InitializedEntity &Parent)
3423	: Parent(&Parent), Index(Index)
3424	{
3425	if (const ArrayType *AT = Context.getAsArrayType(T: Parent.getType())) {
3426	Kind = EK_ArrayElement;
3427	Type = AT->getElementType();
3428	} else if (const VectorType *VT = Parent.getType()->getAs<VectorType>()) {
3429	Kind = EK_VectorElement;
3430	Type = VT->getElementType();
3431	} else {
3432	const ComplexType *CT = Parent.getType()->getAs<ComplexType>();
3433	assert(CT && "Unexpected type");
3434	Kind = EK_ComplexElement;
3435	Type = CT->getElementType();
3436	}
3437	}
3438
3439	InitializedEntity
3440	InitializedEntity::InitializeBase(ASTContext &Context,
3441	const CXXBaseSpecifier *Base,
3442	bool IsInheritedVirtualBase,
3443	const InitializedEntity *Parent) {
3444	InitializedEntity Result;
3445	Result.Kind = EK_Base;
3446	Result.Parent = Parent;
3447	Result.Base = {Base, IsInheritedVirtualBase};
3448	Result.Type = Base->getType();
3449	return Result;
3450	}
3451
3452	DeclarationName InitializedEntity::getName() const {
3453	switch (getKind()) {
3454	case EK_Parameter:
3455	case EK_Parameter_CF_Audited: {
3456	ParmVarDecl *D = Parameter.getPointer();
3457	return (D ? D->getDeclName() : DeclarationName());
3458	}
3459
3460	case EK_Variable:
3461	case EK_Member:
3462	case EK_ParenAggInitMember:
3463	case EK_Binding:
3464	case EK_TemplateParameter:
3465	return Variable.VariableOrMember->getDeclName();
3466
3467	case EK_LambdaCapture:
3468	return DeclarationName(Capture.VarID);
3469
3470	case EK_Result:
3471	case EK_StmtExprResult:
3472	case EK_Exception:
3473	case EK_New:
3474	case EK_Temporary:
3475	case EK_Base:
3476	case EK_Delegating:
3477	case EK_ArrayElement:
3478	case EK_VectorElement:
3479	case EK_ComplexElement:
3480	case EK_BlockElement:
3481	case EK_LambdaToBlockConversionBlockElement:
3482	case EK_CompoundLiteralInit:
3483	case EK_RelatedResult:
3484	return DeclarationName();
3485	}
3486
3487	llvm_unreachable("Invalid EntityKind!");
3488	}
3489
3490	ValueDecl *InitializedEntity::getDecl() const {
3491	switch (getKind()) {
3492	case EK_Variable:
3493	case EK_Member:
3494	case EK_ParenAggInitMember:
3495	case EK_Binding:
3496	case EK_TemplateParameter:
3497	return Variable.VariableOrMember;
3498
3499	case EK_Parameter:
3500	case EK_Parameter_CF_Audited:
3501	return Parameter.getPointer();
3502
3503	case EK_Result:
3504	case EK_StmtExprResult:
3505	case EK_Exception:
3506	case EK_New:
3507	case EK_Temporary:
3508	case EK_Base:
3509	case EK_Delegating:
3510	case EK_ArrayElement:
3511	case EK_VectorElement:
3512	case EK_ComplexElement:
3513	case EK_BlockElement:
3514	case EK_LambdaToBlockConversionBlockElement:
3515	case EK_LambdaCapture:
3516	case EK_CompoundLiteralInit:
3517	case EK_RelatedResult:
3518	return nullptr;
3519	}
3520
3521	llvm_unreachable("Invalid EntityKind!");
3522	}
3523
3524	bool InitializedEntity::allowsNRVO() const {
3525	switch (getKind()) {
3526	case EK_Result:
3527	case EK_Exception:
3528	return LocAndNRVO.NRVO;
3529
3530	case EK_StmtExprResult:
3531	case EK_Variable:
3532	case EK_Parameter:
3533	case EK_Parameter_CF_Audited:
3534	case EK_TemplateParameter:
3535	case EK_Member:
3536	case EK_ParenAggInitMember:
3537	case EK_Binding:
3538	case EK_New:
3539	case EK_Temporary:
3540	case EK_CompoundLiteralInit:
3541	case EK_Base:
3542	case EK_Delegating:
3543	case EK_ArrayElement:
3544	case EK_VectorElement:
3545	case EK_ComplexElement:
3546	case EK_BlockElement:
3547	case EK_LambdaToBlockConversionBlockElement:
3548	case EK_LambdaCapture:
3549	case EK_RelatedResult:
3550	break;
3551	}
3552
3553	return false;
3554	}
3555
3556	unsigned InitializedEntity::dumpImpl(raw_ostream &OS) const {
3557	assert(getParent() != this);
3558	unsigned Depth = getParent() ? getParent()->dumpImpl(OS) : 0;
3559	for (unsigned I = 0; I != Depth; ++I)
3560	OS << "`-";
3561
3562	switch (getKind()) {
3563	case EK_Variable: OS << "Variable"; break;
3564	case EK_Parameter: OS << "Parameter"; break;
3565	case EK_Parameter_CF_Audited: OS << "CF audited function Parameter";
3566	break;
3567	case EK_TemplateParameter: OS << "TemplateParameter"; break;
3568	case EK_Result: OS << "Result"; break;
3569	case EK_StmtExprResult: OS << "StmtExprResult"; break;
3570	case EK_Exception: OS << "Exception"; break;
3571	case EK_Member:
3572	case EK_ParenAggInitMember:
3573	OS << "Member";
3574	break;
3575	case EK_Binding: OS << "Binding"; break;
3576	case EK_New: OS << "New"; break;
3577	case EK_Temporary: OS << "Temporary"; break;
3578	case EK_CompoundLiteralInit: OS << "CompoundLiteral";break;
3579	case EK_RelatedResult: OS << "RelatedResult"; break;
3580	case EK_Base: OS << "Base"; break;
3581	case EK_Delegating: OS << "Delegating"; break;
3582	case EK_ArrayElement: OS << "ArrayElement " << Index; break;
3583	case EK_VectorElement: OS << "VectorElement " << Index; break;
3584	case EK_ComplexElement: OS << "ComplexElement " << Index; break;
3585	case EK_BlockElement: OS << "Block"; break;
3586	case EK_LambdaToBlockConversionBlockElement:
3587	OS << "Block (lambda)";
3588	break;
3589	case EK_LambdaCapture:
3590	OS << "LambdaCapture ";
3591	OS << DeclarationName(Capture.VarID);
3592	break;
3593	}
3594
3595	if (auto *D = getDecl()) {
3596	OS << " ";
3597	D->printQualifiedName(OS);
3598	}
3599
3600	OS << " '" << getType() << "'\n";
3601
3602	return Depth + 1;
3603	}
3604
3605	LLVM_DUMP_METHOD void InitializedEntity::dump() const {
3606	dumpImpl(OS&: llvm::errs());
3607	}
3608
3609	//===----------------------------------------------------------------------===//
3610	// Initialization sequence
3611	//===----------------------------------------------------------------------===//
3612
3613	void InitializationSequence::Step::Destroy() {
3614	switch (Kind) {
3615	case SK_ResolveAddressOfOverloadedFunction:
3616	case SK_CastDerivedToBasePRValue:
3617	case SK_CastDerivedToBaseXValue:
3618	case SK_CastDerivedToBaseLValue:
3619	case SK_BindReference:
3620	case SK_BindReferenceToTemporary:
3621	case SK_FinalCopy:
3622	case SK_ExtraneousCopyToTemporary:
3623	case SK_UserConversion:
3624	case SK_QualificationConversionPRValue:
3625	case SK_QualificationConversionXValue:
3626	case SK_QualificationConversionLValue:
3627	case SK_FunctionReferenceConversion:
3628	case SK_AtomicConversion:
3629	case SK_ListInitialization:
3630	case SK_UnwrapInitList:
3631	case SK_RewrapInitList:
3632	case SK_ConstructorInitialization:
3633	case SK_ConstructorInitializationFromList:
3634	case SK_ZeroInitialization:
3635	case SK_CAssignment:
3636	case SK_StringInit:
3637	case SK_ObjCObjectConversion:
3638	case SK_ArrayLoopIndex:
3639	case SK_ArrayLoopInit:
3640	case SK_ArrayInit:
3641	case SK_GNUArrayInit:
3642	case SK_ParenthesizedArrayInit:
3643	case SK_PassByIndirectCopyRestore:
3644	case SK_PassByIndirectRestore:
3645	case SK_ProduceObjCObject:
3646	case SK_StdInitializerList:
3647	case SK_StdInitializerListConstructorCall:
3648	case SK_OCLSamplerInit:
3649	case SK_OCLZeroOpaqueType:
3650	case SK_ParenthesizedListInit:
3651	break;
3652
3653	case SK_ConversionSequence:
3654	case SK_ConversionSequenceNoNarrowing:
3655	delete ICS;
3656	}
3657	}
3658
3659	bool InitializationSequence::isDirectReferenceBinding() const {
3660	// There can be some lvalue adjustments after the SK_BindReference step.
3661	for (const Step &S : llvm::reverse(C: Steps)) {
3662	if (S.Kind == SK_BindReference)
3663	return true;
3664	if (S.Kind == SK_BindReferenceToTemporary)
3665	return false;
3666	}
3667	return false;
3668	}
3669
3670	bool InitializationSequence::isAmbiguous() const {
3671	if (!Failed())
3672	return false;
3673
3674	switch (getFailureKind()) {
3675	case FK_TooManyInitsForReference:
3676	case FK_ParenthesizedListInitForReference:
3677	case FK_ArrayNeedsInitList:
3678	case FK_ArrayNeedsInitListOrStringLiteral:
3679	case FK_ArrayNeedsInitListOrWideStringLiteral:
3680	case FK_NarrowStringIntoWideCharArray:
3681	case FK_WideStringIntoCharArray:
3682	case FK_IncompatWideStringIntoWideChar:
3683	case FK_PlainStringIntoUTF8Char:
3684	case FK_UTF8StringIntoPlainChar:
3685	case FK_AddressOfOverloadFailed: // FIXME: Could do better
3686	case FK_NonConstLValueReferenceBindingToTemporary:
3687	case FK_NonConstLValueReferenceBindingToBitfield:
3688	case FK_NonConstLValueReferenceBindingToVectorElement:
3689	case FK_NonConstLValueReferenceBindingToMatrixElement:
3690	case FK_NonConstLValueReferenceBindingToUnrelated:
3691	case FK_RValueReferenceBindingToLValue:
3692	case FK_ReferenceAddrspaceMismatchTemporary:
3693	case FK_ReferenceInitDropsQualifiers:
3694	case FK_ReferenceInitFailed:
3695	case FK_ConversionFailed:
3696	case FK_ConversionFromPropertyFailed:
3697	case FK_TooManyInitsForScalar:
3698	case FK_ParenthesizedListInitForScalar:
3699	case FK_ReferenceBindingToInitList:
3700	case FK_InitListBadDestinationType:
3701	case FK_DefaultInitOfConst:
3702	case FK_Incomplete:
3703	case FK_ArrayTypeMismatch:
3704	case FK_NonConstantArrayInit:
3705	case FK_ListInitializationFailed:
3706	case FK_VariableLengthArrayHasInitializer:
3707	case FK_PlaceholderType:
3708	case FK_ExplicitConstructor:
3709	case FK_AddressOfUnaddressableFunction:
3710	case FK_ParenthesizedListInitFailed:
3711	case FK_DesignatedInitForNonAggregate:
3712	return false;
3713
3714	case FK_ReferenceInitOverloadFailed:
3715	case FK_UserConversionOverloadFailed:
3716	case FK_ConstructorOverloadFailed:
3717	case FK_ListConstructorOverloadFailed:
3718	return FailedOverloadResult == OR_Ambiguous;
3719	}
3720
3721	llvm_unreachable("Invalid EntityKind!");
3722	}
3723
3724	bool InitializationSequence::isConstructorInitialization() const {
3725	return !Steps.empty() && Steps.back().Kind == SK_ConstructorInitialization;
3726	}
3727
3728	void
3729	InitializationSequence
3730	::AddAddressOverloadResolutionStep(FunctionDecl *Function,
3731	DeclAccessPair Found,
3732	bool HadMultipleCandidates) {
3733	Step S;
3734	S.Kind = SK_ResolveAddressOfOverloadedFunction;
3735	S.Type = Function->getType();
3736	S.Function.HadMultipleCandidates = HadMultipleCandidates;
3737	S.Function.Function = Function;
3738	S.Function.FoundDecl = Found;
3739	Steps.push_back(Elt: S);
3740	}
3741
3742	void InitializationSequence::AddDerivedToBaseCastStep(QualType BaseType,
3743	ExprValueKind VK) {
3744	Step S;
3745	switch (VK) {
3746	case VK_PRValue:
3747	S.Kind = SK_CastDerivedToBasePRValue;
3748	break;
3749	case VK_XValue: S.Kind = SK_CastDerivedToBaseXValue; break;
3750	case VK_LValue: S.Kind = SK_CastDerivedToBaseLValue; break;
3751	}
3752	S.Type = BaseType;
3753	Steps.push_back(Elt: S);
3754	}
3755
3756	void InitializationSequence::AddReferenceBindingStep(QualType T,
3757	bool BindingTemporary) {
3758	Step S;
3759	S.Kind = BindingTemporary? SK_BindReferenceToTemporary : SK_BindReference;
3760	S.Type = T;
3761	Steps.push_back(Elt: S);
3762	}
3763
3764	void InitializationSequence::AddFinalCopy(QualType T) {
3765	Step S;
3766	S.Kind = SK_FinalCopy;
3767	S.Type = T;
3768	Steps.push_back(Elt: S);
3769	}
3770
3771	void InitializationSequence::AddExtraneousCopyToTemporary(QualType T) {
3772	Step S;
3773	S.Kind = SK_ExtraneousCopyToTemporary;
3774	S.Type = T;
3775	Steps.push_back(Elt: S);
3776	}
3777
3778	void
3779	InitializationSequence::AddUserConversionStep(FunctionDecl *Function,
3780	DeclAccessPair FoundDecl,
3781	QualType T,
3782	bool HadMultipleCandidates) {
3783	Step S;
3784	S.Kind = SK_UserConversion;
3785	S.Type = T;
3786	S.Function.HadMultipleCandidates = HadMultipleCandidates;
3787	S.Function.Function = Function;
3788	S.Function.FoundDecl = FoundDecl;
3789	Steps.push_back(Elt: S);
3790	}
3791
3792	void InitializationSequence::AddQualificationConversionStep(QualType Ty,
3793	ExprValueKind VK) {
3794	Step S;
3795	S.Kind = SK_QualificationConversionPRValue; // work around a gcc warning
3796	switch (VK) {
3797	case VK_PRValue:
3798	S.Kind = SK_QualificationConversionPRValue;
3799	break;
3800	case VK_XValue:
3801	S.Kind = SK_QualificationConversionXValue;
3802	break;
3803	case VK_LValue:
3804	S.Kind = SK_QualificationConversionLValue;
3805	break;
3806	}
3807	S.Type = Ty;
3808	Steps.push_back(Elt: S);
3809	}
3810
3811	void InitializationSequence::AddFunctionReferenceConversionStep(QualType Ty) {
3812	Step S;
3813	S.Kind = SK_FunctionReferenceConversion;
3814	S.Type = Ty;
3815	Steps.push_back(Elt: S);
3816	}
3817
3818	void InitializationSequence::AddAtomicConversionStep(QualType Ty) {
3819	Step S;
3820	S.Kind = SK_AtomicConversion;
3821	S.Type = Ty;
3822	Steps.push_back(Elt: S);
3823	}
3824
3825	void InitializationSequence::AddConversionSequenceStep(
3826	const ImplicitConversionSequence &ICS, QualType T,
3827	bool TopLevelOfInitList) {
3828	Step S;
3829	S.Kind = TopLevelOfInitList ? SK_ConversionSequenceNoNarrowing
3830	: SK_ConversionSequence;
3831	S.Type = T;
3832	S.ICS = new ImplicitConversionSequence(ICS);
3833	Steps.push_back(Elt: S);
3834	}
3835
3836	void InitializationSequence::AddListInitializationStep(QualType T) {
3837	Step S;
3838	S.Kind = SK_ListInitialization;
3839	S.Type = T;
3840	Steps.push_back(Elt: S);
3841	}
3842
3843	void InitializationSequence::AddConstructorInitializationStep(
3844	DeclAccessPair FoundDecl, CXXConstructorDecl *Constructor, QualType T,
3845	bool HadMultipleCandidates, bool FromInitList, bool AsInitList) {
3846	Step S;
3847	S.Kind = FromInitList ? AsInitList ? SK_StdInitializerListConstructorCall
3848	: SK_ConstructorInitializationFromList
3849	: SK_ConstructorInitialization;
3850	S.Type = T;
3851	S.Function.HadMultipleCandidates = HadMultipleCandidates;
3852	S.Function.Function = Constructor;
3853	S.Function.FoundDecl = FoundDecl;
3854	Steps.push_back(Elt: S);
3855	}
3856
3857	void InitializationSequence::AddZeroInitializationStep(QualType T) {
3858	Step S;
3859	S.Kind = SK_ZeroInitialization;
3860	S.Type = T;
3861	Steps.push_back(Elt: S);
3862	}
3863
3864	void InitializationSequence::AddCAssignmentStep(QualType T) {
3865	Step S;
3866	S.Kind = SK_CAssignment;
3867	S.Type = T;
3868	Steps.push_back(Elt: S);
3869	}
3870
3871	void InitializationSequence::AddStringInitStep(QualType T) {
3872	Step S;
3873	S.Kind = SK_StringInit;
3874	S.Type = T;
3875	Steps.push_back(Elt: S);
3876	}
3877
3878	void InitializationSequence::AddObjCObjectConversionStep(QualType T) {
3879	Step S;
3880	S.Kind = SK_ObjCObjectConversion;
3881	S.Type = T;
3882	Steps.push_back(Elt: S);
3883	}
3884
3885	void InitializationSequence::AddArrayInitStep(QualType T, bool IsGNUExtension) {
3886	Step S;
3887	S.Kind = IsGNUExtension ? SK_GNUArrayInit : SK_ArrayInit;
3888	S.Type = T;
3889	Steps.push_back(Elt: S);
3890	}
3891
3892	void InitializationSequence::AddArrayInitLoopStep(QualType T, QualType EltT) {
3893	Step S;
3894	S.Kind = SK_ArrayLoopIndex;
3895	S.Type = EltT;
3896	Steps.insert(I: Steps.begin(), Elt: S);
3897
3898	S.Kind = SK_ArrayLoopInit;
3899	S.Type = T;
3900	Steps.push_back(Elt: S);
3901	}
3902
3903	void InitializationSequence::AddParenthesizedArrayInitStep(QualType T) {
3904	Step S;
3905	S.Kind = SK_ParenthesizedArrayInit;
3906	S.Type = T;
3907	Steps.push_back(Elt: S);
3908	}
3909
3910	void InitializationSequence::AddPassByIndirectCopyRestoreStep(QualType type,
3911	bool shouldCopy) {
3912	Step s;
3913	s.Kind = (shouldCopy ? SK_PassByIndirectCopyRestore
3914	: SK_PassByIndirectRestore);
3915	s.Type = type;
3916	Steps.push_back(Elt: s);
3917	}
3918
3919	void InitializationSequence::AddProduceObjCObjectStep(QualType T) {
3920	Step S;
3921	S.Kind = SK_ProduceObjCObject;
3922	S.Type = T;
3923	Steps.push_back(Elt: S);
3924	}
3925
3926	void InitializationSequence::AddStdInitializerListConstructionStep(QualType T) {
3927	Step S;
3928	S.Kind = SK_StdInitializerList;
3929	S.Type = T;
3930	Steps.push_back(Elt: S);
3931	}
3932
3933	void InitializationSequence::AddOCLSamplerInitStep(QualType T) {
3934	Step S;
3935	S.Kind = SK_OCLSamplerInit;
3936	S.Type = T;
3937	Steps.push_back(Elt: S);
3938	}
3939
3940	void InitializationSequence::AddOCLZeroOpaqueTypeStep(QualType T) {
3941	Step S;
3942	S.Kind = SK_OCLZeroOpaqueType;
3943	S.Type = T;
3944	Steps.push_back(Elt: S);
3945	}
3946
3947	void InitializationSequence::AddParenthesizedListInitStep(QualType T) {
3948	Step S;
3949	S.Kind = SK_ParenthesizedListInit;
3950	S.Type = T;
3951	Steps.push_back(Elt: S);
3952	}
3953
3954	void InitializationSequence::RewrapReferenceInitList(QualType T,
3955	InitListExpr *Syntactic) {
3956	assert(Syntactic->getNumInits() == 1 &&
3957	"Can only rewrap trivial init lists.");
3958	Step S;
3959	S.Kind = SK_UnwrapInitList;
3960	S.Type = Syntactic->getInit(Init: 0)->getType();
3961	Steps.insert(I: Steps.begin(), Elt: S);
3962
3963	S.Kind = SK_RewrapInitList;
3964	S.Type = T;
3965	S.WrappingSyntacticList = Syntactic;
3966	Steps.push_back(Elt: S);
3967	}
3968
3969	void InitializationSequence::SetOverloadFailure(FailureKind Failure,
3970	OverloadingResult Result) {
3971	setSequenceKind(FailedSequence);
3972	this->Failure = Failure;
3973	this->FailedOverloadResult = Result;
3974	}
3975
3976	//===----------------------------------------------------------------------===//
3977	// Attempt initialization
3978	//===----------------------------------------------------------------------===//
3979
3980	/// Tries to add a zero initializer. Returns true if that worked.
3981	static bool
3982	maybeRecoverWithZeroInitialization(Sema &S, InitializationSequence &Sequence,
3983	const InitializedEntity &Entity) {
3984	if (Entity.getKind() != InitializedEntity::EK_Variable)
3985	return false;
3986
3987	VarDecl *VD = cast<VarDecl>(Val: Entity.getDecl());
3988	if (VD->getInit() || VD->getEndLoc().isMacroID())
3989	return false;
3990
3991	QualType VariableTy = VD->getType().getCanonicalType();
3992	SourceLocation Loc = S.getLocForEndOfToken(Loc: VD->getEndLoc());
3993	std::string Init = S.getFixItZeroInitializerForType(T: VariableTy, Loc);
3994	if (!Init.empty()) {
3995	Sequence.AddZeroInitializationStep(T: Entity.getType());
3996	Sequence.SetZeroInitializationFixit(Fixit: Init, L: Loc);
3997	return true;
3998	}
3999	return false;
4000	}
4001
4002	static void MaybeProduceObjCObject(Sema &S,
4003	InitializationSequence &Sequence,
4004	const InitializedEntity &Entity) {
4005	if (!S.getLangOpts().ObjCAutoRefCount) return;
4006
4007	/// When initializing a parameter, produce the value if it's marked
4008	/// __attribute__((ns_consumed)).
4009	if (Entity.isParameterKind()) {
4010	if (!Entity.isParameterConsumed())
4011	return;
4012
4013	assert(Entity.getType()->isObjCRetainableType() &&
4014	"consuming an object of unretainable type?");
4015	Sequence.AddProduceObjCObjectStep(T: Entity.getType());
4016
4017	/// When initializing a return value, if the return type is a
4018	/// retainable type, then returns need to immediately retain the
4019	/// object. If an autorelease is required, it will be done at the
4020	/// last instant.
4021	} else if (Entity.getKind() == InitializedEntity::EK_Result ||
4022	Entity.getKind() == InitializedEntity::EK_StmtExprResult) {
4023	if (!Entity.getType()->isObjCRetainableType())
4024	return;
4025
4026	Sequence.AddProduceObjCObjectStep(T: Entity.getType());
4027	}
4028	}
4029
4030	static void TryListInitialization(Sema &S,
4031	const InitializedEntity &Entity,
4032	const InitializationKind &Kind,
4033	InitListExpr *InitList,
4034	InitializationSequence &Sequence,
4035	bool TreatUnavailableAsInvalid);
4036
4037	/// When initializing from init list via constructor, handle
4038	/// initialization of an object of type std::initializer_list<T>.
4039	///
4040	/// \return true if we have handled initialization of an object of type
4041	/// std::initializer_list<T>, false otherwise.
4042	static bool TryInitializerListConstruction(Sema &S,
4043	InitListExpr *List,
4044	QualType DestType,
4045	InitializationSequence &Sequence,
4046	bool TreatUnavailableAsInvalid) {
4047	QualType E;
4048	if (!S.isStdInitializerList(Ty: DestType, Element: &E))
4049	return false;
4050
4051	if (!S.isCompleteType(Loc: List->getExprLoc(), T: E)) {
4052	Sequence.setIncompleteTypeFailure(E);
4053	return true;
4054	}
4055
4056	// Try initializing a temporary array from the init list.
4057	QualType ArrayType = S.Context.getConstantArrayType(
4058	EltTy: E.withConst(),
4059	ArySize: llvm::APInt(S.Context.getTypeSize(T: S.Context.getSizeType()),
4060	List->getNumInits()),
4061	SizeExpr: nullptr, ASM: clang::ArraySizeModifier::Normal, IndexTypeQuals: 0);
4062	InitializedEntity HiddenArray =
4063	InitializedEntity::InitializeTemporary(Type: ArrayType);
4064	InitializationKind Kind = InitializationKind::CreateDirectList(
4065	List->getExprLoc(), List->getBeginLoc(), List->getEndLoc());
4066	TryListInitialization(S, Entity: HiddenArray, Kind, InitList: List, Sequence,
4067	TreatUnavailableAsInvalid);
4068	if (Sequence)
4069	Sequence.AddStdInitializerListConstructionStep(T: DestType);
4070	return true;
4071	}
4072
4073	/// Determine if the constructor has the signature of a copy or move
4074	/// constructor for the type T of the class in which it was found. That is,
4075	/// determine if its first parameter is of type T or reference to (possibly
4076	/// cv-qualified) T.
4077	static bool hasCopyOrMoveCtorParam(ASTContext &Ctx,
4078	const ConstructorInfo &Info) {
4079	if (Info.Constructor->getNumParams() == 0)
4080	return false;
4081
4082	QualType ParmT =
4083	Info.Constructor->getParamDecl(0)->getType().getNonReferenceType();
4084	QualType ClassT =
4085	Ctx.getRecordType(Decl: cast<CXXRecordDecl>(Info.FoundDecl->getDeclContext()));
4086
4087	return Ctx.hasSameUnqualifiedType(T1: ParmT, T2: ClassT);
4088	}
4089
4090	static OverloadingResult ResolveConstructorOverload(
4091	Sema &S, SourceLocation DeclLoc, MultiExprArg Args,
4092	OverloadCandidateSet &CandidateSet, QualType DestType,
4093	DeclContext::lookup_result Ctors, OverloadCandidateSet::iterator &Best,
4094	bool CopyInitializing, bool AllowExplicit, bool OnlyListConstructors,
4095	bool IsListInit, bool RequireActualConstructor,
4096	bool SecondStepOfCopyInit = false) {
4097	CandidateSet.clear(CSK: OverloadCandidateSet::CSK_InitByConstructor);
4098	CandidateSet.setDestAS(DestType.getQualifiers().getAddressSpace());
4099
4100	for (NamedDecl *D : Ctors) {
4101	auto Info = getConstructorInfo(ND: D);
4102	if (!Info.Constructor || Info.Constructor->isInvalidDecl())
4103	continue;
4104
4105	if (OnlyListConstructors && !S.isInitListConstructor(Info.Constructor))
4106	continue;
4107
4108	// C++11 [over.best.ics]p4:
4109	// ... and the constructor or user-defined conversion function is a
4110	// candidate by
4111	// - 13.3.1.3, when the argument is the temporary in the second step
4112	// of a class copy-initialization, or
4113	// - 13.3.1.4, 13.3.1.5, or 13.3.1.6 (in all cases), [not handled here]
4114	// - the second phase of 13.3.1.7 when the initializer list has exactly
4115	// one element that is itself an initializer list, and the target is
4116	// the first parameter of a constructor of class X, and the conversion
4117	// is to X or reference to (possibly cv-qualified X),
4118	// user-defined conversion sequences are not considered.
4119	bool SuppressUserConversions =
4120	SecondStepOfCopyInit ||
4121	(IsListInit && Args.size() == 1 && isa<InitListExpr>(Val: Args[0]) &&
4122	hasCopyOrMoveCtorParam(Ctx&: S.Context, Info));
4123
4124	if (Info.ConstructorTmpl)
4125	S.AddTemplateOverloadCandidate(
4126	FunctionTemplate: Info.ConstructorTmpl, FoundDecl: Info.FoundDecl,
4127	/*ExplicitArgs*/ ExplicitTemplateArgs: nullptr, Args, CandidateSet, SuppressUserConversions,
4128	/*PartialOverloading=*/false, AllowExplicit);
4129	else {
4130	// C++ [over.match.copy]p1:
4131	// - When initializing a temporary to be bound to the first parameter
4132	// of a constructor [for type T] that takes a reference to possibly
4133	// cv-qualified T as its first argument, called with a single
4134	// argument in the context of direct-initialization, explicit
4135	// conversion functions are also considered.
4136	// FIXME: What if a constructor template instantiates to such a signature?
4137	bool AllowExplicitConv = AllowExplicit && !CopyInitializing &&
4138	Args.size() == 1 &&
4139	hasCopyOrMoveCtorParam(Ctx&: S.Context, Info);
4140	S.AddOverloadCandidate(Info.Constructor, Info.FoundDecl, Args,
4141	CandidateSet, SuppressUserConversions,
4142	/*PartialOverloading=*/false, AllowExplicit,
4143	AllowExplicitConv);
4144	}
4145	}
4146
4147	// FIXME: Work around a bug in C++17 guaranteed copy elision.
4148	//
4149	// When initializing an object of class type T by constructor
4150	// ([over.match.ctor]) or by list-initialization ([over.match.list])
4151	// from a single expression of class type U, conversion functions of
4152	// U that convert to the non-reference type cv T are candidates.
4153	// Explicit conversion functions are only candidates during
4154	// direct-initialization.
4155	//
4156	// Note: SecondStepOfCopyInit is only ever true in this case when
4157	// evaluating whether to produce a C++98 compatibility warning.
4158	if (S.getLangOpts().CPlusPlus17 && Args.size() == 1 &&
4159	!RequireActualConstructor && !SecondStepOfCopyInit) {
4160	Expr *Initializer = Args[0];
4161	auto *SourceRD = Initializer->getType()->getAsCXXRecordDecl();
4162	if (SourceRD && S.isCompleteType(Loc: DeclLoc, T: Initializer->getType())) {
4163	const auto &Conversions = SourceRD->getVisibleConversionFunctions();
4164	for (auto I = Conversions.begin(), E = Conversions.end(); I != E; ++I) {
4165	NamedDecl *D = *I;
4166	CXXRecordDecl *ActingDC = cast<CXXRecordDecl>(D->getDeclContext());
4167	D = D->getUnderlyingDecl();
4168
4169	FunctionTemplateDecl *ConvTemplate = dyn_cast<FunctionTemplateDecl>(Val: D);
4170	CXXConversionDecl *Conv;
4171	if (ConvTemplate)
4172	Conv = cast<CXXConversionDecl>(Val: ConvTemplate->getTemplatedDecl());
4173	else
4174	Conv = cast<CXXConversionDecl>(Val: D);
4175
4176	if (ConvTemplate)
4177	S.AddTemplateConversionCandidate(
4178	FunctionTemplate: ConvTemplate, FoundDecl: I.getPair(), ActingContext: ActingDC, From: Initializer, ToType: DestType,
4179	CandidateSet, AllowObjCConversionOnExplicit: AllowExplicit, AllowExplicit,
4180	/*AllowResultConversion*/ false);
4181	else
4182	S.AddConversionCandidate(Conversion: Conv, FoundDecl: I.getPair(), ActingContext: ActingDC, From: Initializer,
4183	ToType: DestType, CandidateSet, AllowObjCConversionOnExplicit: AllowExplicit,
4184	AllowExplicit,
4185	/*AllowResultConversion*/ false);
4186	}
4187	}
4188	}
4189
4190	// Perform overload resolution and return the result.
4191	return CandidateSet.BestViableFunction(S, Loc: DeclLoc, Best);
4192	}
4193
4194	/// Attempt initialization by constructor (C++ [dcl.init]), which
4195	/// enumerates the constructors of the initialized entity and performs overload
4196	/// resolution to select the best.
4197	/// \param DestType The destination class type.
4198	/// \param DestArrayType The destination type, which is either DestType or
4199	/// a (possibly multidimensional) array of DestType.
4200	/// \param IsListInit Is this list-initialization?
4201	/// \param IsInitListCopy Is this non-list-initialization resulting from a
4202	/// list-initialization from {x} where x is the same
4203	/// type as the entity?
4204	static void TryConstructorInitialization(Sema &S,
4205	const InitializedEntity &Entity,
4206	const InitializationKind &Kind,
4207	MultiExprArg Args, QualType DestType,
4208	QualType DestArrayType,
4209	InitializationSequence &Sequence,
4210	bool IsListInit = false,
4211	bool IsInitListCopy = false) {
4212	assert(((!IsListInit && !IsInitListCopy) ||
4213	(Args.size() == 1 && isa<InitListExpr>(Args[0]))) &&
4214	"IsListInit/IsInitListCopy must come with a single initializer list "
4215	"argument.");
4216	InitListExpr *ILE =
4217	(IsListInit || IsInitListCopy) ? cast<InitListExpr>(Val: Args[0]) : nullptr;
4218	MultiExprArg UnwrappedArgs =
4219	ILE ? MultiExprArg(ILE->getInits(), ILE->getNumInits()) : Args;
4220
4221	// The type we're constructing needs to be complete.
4222	if (!S.isCompleteType(Loc: Kind.getLocation(), T: DestType)) {
4223	Sequence.setIncompleteTypeFailure(DestType);
4224	return;
4225	}
4226
4227	bool RequireActualConstructor =
4228	!(Entity.getKind() != InitializedEntity::EK_Base &&
4229	Entity.getKind() != InitializedEntity::EK_Delegating &&
4230	Entity.getKind() !=
4231	InitializedEntity::EK_LambdaToBlockConversionBlockElement);
4232
4233	// C++17 [dcl.init]p17:
4234	// - If the initializer expression is a prvalue and the cv-unqualified
4235	// version of the source type is the same class as the class of the
4236	// destination, the initializer expression is used to initialize the
4237	// destination object.
4238	// Per DR (no number yet), this does not apply when initializing a base
4239	// class or delegating to another constructor from a mem-initializer.
4240	// ObjC++: Lambda captured by the block in the lambda to block conversion
4241	// should avoid copy elision.
4242	if (S.getLangOpts().CPlusPlus17 && !RequireActualConstructor &&
4243	UnwrappedArgs.size() == 1 && UnwrappedArgs[0]->isPRValue() &&
4244	S.Context.hasSameUnqualifiedType(T1: UnwrappedArgs[0]->getType(), T2: DestType)) {
4245	// Convert qualifications if necessary.
4246	Sequence.AddQualificationConversionStep(Ty: DestType, VK: VK_PRValue);
4247	if (ILE)
4248	Sequence.RewrapReferenceInitList(T: DestType, Syntactic: ILE);
4249	return;
4250	}
4251
4252	const RecordType *DestRecordType = DestType->getAs<RecordType>();
4253	assert(DestRecordType && "Constructor initialization requires record type");
4254	CXXRecordDecl *DestRecordDecl
4255	= cast<CXXRecordDecl>(Val: DestRecordType->getDecl());
4256
4257	// Build the candidate set directly in the initialization sequence
4258	// structure, so that it will persist if we fail.
4259	OverloadCandidateSet &CandidateSet = Sequence.getFailedCandidateSet();
4260
4261	// Determine whether we are allowed to call explicit constructors or
4262	// explicit conversion operators.
4263	bool AllowExplicit = Kind.AllowExplicit() || IsListInit;
4264	bool CopyInitialization = Kind.getKind() == InitializationKind::IK_Copy;
4265
4266	// - Otherwise, if T is a class type, constructors are considered. The
4267	// applicable constructors are enumerated, and the best one is chosen
4268	// through overload resolution.
4269	DeclContext::lookup_result Ctors = S.LookupConstructors(Class: DestRecordDecl);
4270
4271	OverloadingResult Result = OR_No_Viable_Function;
4272	OverloadCandidateSet::iterator Best;
4273	bool AsInitializerList = false;
4274
4275	// C++11 [over.match.list]p1, per DR1467:
4276	// When objects of non-aggregate type T are list-initialized, such that
4277	// 8.5.4 [dcl.init.list] specifies that overload resolution is performed
4278	// according to the rules in this section, overload resolution selects
4279	// the constructor in two phases:
4280	//
4281	// - Initially, the candidate functions are the initializer-list
4282	// constructors of the class T and the argument list consists of the
4283	// initializer list as a single argument.
4284	if (IsListInit) {
4285	AsInitializerList = true;
4286
4287	// If the initializer list has no elements and T has a default constructor,
4288	// the first phase is omitted.
4289	if (!(UnwrappedArgs.empty() && S.LookupDefaultConstructor(Class: DestRecordDecl)))
4290	Result = ResolveConstructorOverload(
4291	S, DeclLoc: Kind.getLocation(), Args, CandidateSet, DestType, Ctors, Best,
4292	CopyInitializing: CopyInitialization, AllowExplicit,
4293	/*OnlyListConstructors=*/true, IsListInit, RequireActualConstructor);
4294	}
4295
4296	// C++11 [over.match.list]p1:
4297	// - If no viable initializer-list constructor is found, overload resolution
4298	// is performed again, where the candidate functions are all the
4299	// constructors of the class T and the argument list consists of the
4300	// elements of the initializer list.
4301	if (Result == OR_No_Viable_Function) {
4302	AsInitializerList = false;
4303	Result = ResolveConstructorOverload(
4304	S, DeclLoc: Kind.getLocation(), Args: UnwrappedArgs, CandidateSet, DestType, Ctors,
4305	Best, CopyInitializing: CopyInitialization, AllowExplicit,
4306	/*OnlyListConstructors=*/false, IsListInit, RequireActualConstructor);
4307	}
4308	if (Result) {
4309	Sequence.SetOverloadFailure(
4310	Failure: IsListInit ? InitializationSequence::FK_ListConstructorOverloadFailed
4311	: InitializationSequence::FK_ConstructorOverloadFailed,
4312	Result);
4313
4314	if (Result != OR_Deleted)
4315	return;
4316	}
4317
4318	bool HadMultipleCandidates = (CandidateSet.size() > 1);
4319
4320	// In C++17, ResolveConstructorOverload can select a conversion function
4321	// instead of a constructor.
4322	if (auto *CD = dyn_cast<CXXConversionDecl>(Val: Best->Function)) {
4323	// Add the user-defined conversion step that calls the conversion function.
4324	QualType ConvType = CD->getConversionType();
4325	assert(S.Context.hasSameUnqualifiedType(ConvType, DestType) &&
4326	"should not have selected this conversion function");
4327	Sequence.AddUserConversionStep(CD, Best->FoundDecl, ConvType,
4328	HadMultipleCandidates);
4329	if (!S.Context.hasSameType(T1: ConvType, T2: DestType))
4330	Sequence.AddQualificationConversionStep(Ty: DestType, VK: VK_PRValue);
4331	if (IsListInit)
4332	Sequence.RewrapReferenceInitList(T: Entity.getType(), Syntactic: ILE);
4333	return;
4334	}
4335
4336	CXXConstructorDecl *CtorDecl = cast<CXXConstructorDecl>(Val: Best->Function);
4337	if (Result != OR_Deleted) {
4338	// C++11 [dcl.init]p6:
4339	// If a program calls for the default initialization of an object
4340	// of a const-qualified type T, T shall be a class type with a
4341	// user-provided default constructor.
4342	// C++ core issue 253 proposal:
4343	// If the implicit default constructor initializes all subobjects, no
4344	// initializer should be required.
4345	// The 253 proposal is for example needed to process libstdc++ headers
4346	// in 5.x.
4347	if (Kind.getKind() == InitializationKind::IK_Default &&
4348	Entity.getType().isConstQualified()) {
4349	if (!CtorDecl->getParent()->allowConstDefaultInit()) {
4350	if (!maybeRecoverWithZeroInitialization(S, Sequence, Entity))
4351	Sequence.SetFailed(InitializationSequence::FK_DefaultInitOfConst);
4352	return;
4353	}
4354	}
4355
4356	// C++11 [over.match.list]p1:
4357	// In copy-list-initialization, if an explicit constructor is chosen, the
4358	// initializer is ill-formed.
4359	if (IsListInit && !Kind.AllowExplicit() && CtorDecl->isExplicit()) {
4360	Sequence.SetFailed(InitializationSequence::FK_ExplicitConstructor);
4361	return;
4362	}
4363	}
4364
4365	// [class.copy.elision]p3:
4366	// In some copy-initialization contexts, a two-stage overload resolution
4367	// is performed.
4368	// If the first overload resolution selects a deleted function, we also
4369	// need the initialization sequence to decide whether to perform the second
4370	// overload resolution.
4371	// For deleted functions in other contexts, there is no need to get the
4372	// initialization sequence.
4373	if (Result == OR_Deleted && Kind.getKind() != InitializationKind::IK_Copy)
4374	return;
4375
4376	// Add the constructor initialization step. Any cv-qualification conversion is
4377	// subsumed by the initialization.
4378	Sequence.AddConstructorInitializationStep(
4379	FoundDecl: Best->FoundDecl, Constructor: CtorDecl, T: DestArrayType, HadMultipleCandidates,
4380	FromInitList: IsListInit | IsInitListCopy, AsInitList: AsInitializerList);
4381	}
4382
4383	static bool
4384	ResolveOverloadedFunctionForReferenceBinding(Sema &S,
4385	Expr *Initializer,
4386	QualType &SourceType,
4387	QualType &UnqualifiedSourceType,
4388	QualType UnqualifiedTargetType,
4389	InitializationSequence &Sequence) {
4390	if (S.Context.getCanonicalType(T: UnqualifiedSourceType) ==
4391	S.Context.OverloadTy) {
4392	DeclAccessPair Found;
4393	bool HadMultipleCandidates = false;
4394	if (FunctionDecl *Fn
4395	= S.ResolveAddressOfOverloadedFunction(AddressOfExpr: Initializer,
4396	TargetType: UnqualifiedTargetType,
4397	Complain: false, Found,
4398	pHadMultipleCandidates: &HadMultipleCandidates)) {
4399	Sequence.AddAddressOverloadResolutionStep(Function: Fn, Found,
4400	HadMultipleCandidates);
4401	SourceType = Fn->getType();
4402	UnqualifiedSourceType = SourceType.getUnqualifiedType();
4403	} else if (!UnqualifiedTargetType->isRecordType()) {
4404	Sequence.SetFailed(InitializationSequence::FK_AddressOfOverloadFailed);
4405	return true;
4406	}
4407	}
4408	return false;
4409	}
4410
4411	static void TryReferenceInitializationCore(Sema &S,
4412	const InitializedEntity &Entity,
4413	const InitializationKind &Kind,
4414	Expr *Initializer,
4415	QualType cv1T1, QualType T1,
4416	Qualifiers T1Quals,
4417	QualType cv2T2, QualType T2,
4418	Qualifiers T2Quals,
4419	InitializationSequence &Sequence,
4420	bool TopLevelOfInitList);
4421
4422	static void TryValueInitialization(Sema &S,
4423	const InitializedEntity &Entity,
4424	const InitializationKind &Kind,
4425	InitializationSequence &Sequence,
4426	InitListExpr *InitList = nullptr);
4427
4428	/// Attempt list initialization of a reference.
4429	static void TryReferenceListInitialization(Sema &S,
4430	const InitializedEntity &Entity,
4431	const InitializationKind &Kind,
4432	InitListExpr *InitList,
4433	InitializationSequence &Sequence,
4434	bool TreatUnavailableAsInvalid) {
4435	// First, catch C++03 where this isn't possible.
4436	if (!S.getLangOpts().CPlusPlus11) {
4437	Sequence.SetFailed(InitializationSequence::FK_ReferenceBindingToInitList);
4438	return;
4439	}
4440	// Can't reference initialize a compound literal.
4441	if (Entity.getKind() == InitializedEntity::EK_CompoundLiteralInit) {
4442	Sequence.SetFailed(InitializationSequence::FK_ReferenceBindingToInitList);
4443	return;
4444	}
4445
4446	QualType DestType = Entity.getType();
4447	QualType cv1T1 = DestType->castAs<ReferenceType>()->getPointeeType();
4448	Qualifiers T1Quals;
4449	QualType T1 = S.Context.getUnqualifiedArrayType(T: cv1T1, Quals&: T1Quals);
4450
4451	// Reference initialization via an initializer list works thus:
4452	// If the initializer list consists of a single element that is
4453	// reference-related to the referenced type, bind directly to that element
4454	// (possibly creating temporaries).
4455	// Otherwise, initialize a temporary with the initializer list and
4456	// bind to that.
4457	if (InitList->getNumInits() == 1) {
4458	Expr *Initializer = InitList->getInit(Init: 0);
4459	QualType cv2T2 = S.getCompletedType(E: Initializer);
4460	Qualifiers T2Quals;
4461	QualType T2 = S.Context.getUnqualifiedArrayType(T: cv2T2, Quals&: T2Quals);
4462
4463	// If this fails, creating a temporary wouldn't work either.
4464	if (ResolveOverloadedFunctionForReferenceBinding(S, Initializer, SourceType&: cv2T2, UnqualifiedSourceType&: T2,
4465	UnqualifiedTargetType: T1, Sequence))
4466	return;
4467
4468	SourceLocation DeclLoc = Initializer->getBeginLoc();
4469	Sema::ReferenceCompareResult RefRelationship
4470	= S.CompareReferenceRelationship(Loc: DeclLoc, T1: cv1T1, T2: cv2T2);
4471	if (RefRelationship >= Sema::Ref_Related) {
4472	// Try to bind the reference here.
4473	TryReferenceInitializationCore(S, Entity, Kind, Initializer, cv1T1, T1,
4474	T1Quals, cv2T2, T2, T2Quals, Sequence,
4475	/*TopLevelOfInitList=*/true);
4476	if (Sequence)
4477	Sequence.RewrapReferenceInitList(T: cv1T1, Syntactic: InitList);
4478	return;
4479	}
4480
4481	// Update the initializer if we've resolved an overloaded function.
4482	if (Sequence.step_begin() != Sequence.step_end())
4483	Sequence.RewrapReferenceInitList(T: cv1T1, Syntactic: InitList);
4484	}
4485	// Perform address space compatibility check.
4486	QualType cv1T1IgnoreAS = cv1T1;
4487	if (T1Quals.hasAddressSpace()) {
4488	Qualifiers T2Quals;
4489	(void)S.Context.getUnqualifiedArrayType(T: InitList->getType(), Quals&: T2Quals);
4490	if (!T1Quals.isAddressSpaceSupersetOf(other: T2Quals)) {
4491	Sequence.SetFailed(
4492	InitializationSequence::FK_ReferenceInitDropsQualifiers);
4493	return;
4494	}
4495	// Ignore address space of reference type at this point and perform address
4496	// space conversion after the reference binding step.
4497	cv1T1IgnoreAS =
4498	S.Context.getQualifiedType(T: T1, Qs: T1Quals.withoutAddressSpace());
4499	}
4500	// Not reference-related. Create a temporary and bind to that.
4501	InitializedEntity TempEntity =
4502	InitializedEntity::InitializeTemporary(Type: cv1T1IgnoreAS);
4503
4504	TryListInitialization(S, Entity: TempEntity, Kind, InitList, Sequence,
4505	TreatUnavailableAsInvalid);
4506	if (Sequence) {
4507	if (DestType->isRValueReferenceType() ||
4508	(T1Quals.hasConst() && !T1Quals.hasVolatile())) {
4509	if (S.getLangOpts().CPlusPlus20 &&
4510	isa<IncompleteArrayType>(Val: T1->getUnqualifiedDesugaredType()) &&
4511	DestType->isRValueReferenceType()) {
4512	// C++20 [dcl.init.list]p3.10:
4513	// List-initialization of an object or reference of type T is defined as
4514	// follows:
4515	// ..., unless T is “reference to array of unknown bound of U”, in which
4516	// case the type of the prvalue is the type of x in the declaration U
4517	// x[] H, where H is the initializer list.
4518	Sequence.AddQualificationConversionStep(Ty: cv1T1, VK: clang::VK_PRValue);
4519	}
4520	Sequence.AddReferenceBindingStep(T: cv1T1IgnoreAS,
4521	/*BindingTemporary=*/true);
4522	if (T1Quals.hasAddressSpace())
4523	Sequence.AddQualificationConversionStep(
4524	Ty: cv1T1, VK: DestType->isRValueReferenceType() ? VK_XValue : VK_LValue);
4525	} else
4526	Sequence.SetFailed(
4527	InitializationSequence::FK_NonConstLValueReferenceBindingToTemporary);
4528	}
4529	}
4530
4531	/// Attempt list initialization (C++0x [dcl.init.list])
4532	static void TryListInitialization(Sema &S,
4533	const InitializedEntity &Entity,
4534	const InitializationKind &Kind,
4535	InitListExpr *InitList,
4536	InitializationSequence &Sequence,
4537	bool TreatUnavailableAsInvalid) {
4538	QualType DestType = Entity.getType();
4539
4540	// C++ doesn't allow scalar initialization with more than one argument.
4541	// But C99 complex numbers are scalars and it makes sense there.
4542	if (S.getLangOpts().CPlusPlus && DestType->isScalarType() &&
4543	!DestType->isAnyComplexType() && InitList->getNumInits() > 1) {
4544	Sequence.SetFailed(InitializationSequence::FK_TooManyInitsForScalar);
4545	return;
4546	}
4547	if (DestType->isReferenceType()) {
4548	TryReferenceListInitialization(S, Entity, Kind, InitList, Sequence,
4549	TreatUnavailableAsInvalid);
4550	return;
4551	}
4552
4553	if (DestType->isRecordType() &&
4554	!S.isCompleteType(Loc: InitList->getBeginLoc(), T: DestType)) {
4555	Sequence.setIncompleteTypeFailure(DestType);
4556	return;
4557	}
4558
4559	// C++20 [dcl.init.list]p3:
4560	// - If the braced-init-list contains a designated-initializer-list, T shall
4561	// be an aggregate class. [...] Aggregate initialization is performed.
4562	//
4563	// We allow arrays here too in order to support array designators.
4564	//
4565	// FIXME: This check should precede the handling of reference initialization.
4566	// We follow other compilers in allowing things like 'Aggr &&a = {.x = 1};'
4567	// as a tentative DR resolution.
4568	bool IsDesignatedInit = InitList->hasDesignatedInit();
4569	if (!DestType->isAggregateType() && IsDesignatedInit) {
4570	Sequence.SetFailed(
4571	InitializationSequence::FK_DesignatedInitForNonAggregate);
4572	return;
4573	}
4574
4575	// C++11 [dcl.init.list]p3, per DR1467:
4576	// - If T is a class type and the initializer list has a single element of
4577	// type cv U, where U is T or a class derived from T, the object is
4578	// initialized from that element (by copy-initialization for
4579	// copy-list-initialization, or by direct-initialization for
4580	// direct-list-initialization).
4581	// - Otherwise, if T is a character array and the initializer list has a
4582	// single element that is an appropriately-typed string literal
4583	// (8.5.2 [dcl.init.string]), initialization is performed as described
4584	// in that section.
4585	// - Otherwise, if T is an aggregate, [...] (continue below).
4586	if (S.getLangOpts().CPlusPlus11 && InitList->getNumInits() == 1 &&
4587	!IsDesignatedInit) {
4588	if (DestType->isRecordType()) {
4589	QualType InitType = InitList->getInit(Init: 0)->getType();
4590	if (S.Context.hasSameUnqualifiedType(T1: InitType, T2: DestType) ||
4591	S.IsDerivedFrom(Loc: InitList->getBeginLoc(), Derived: InitType, Base: DestType)) {
4592	Expr *InitListAsExpr = InitList;
4593	TryConstructorInitialization(S, Entity, Kind, Args: InitListAsExpr, DestType,
4594	DestArrayType: DestType, Sequence,
4595	/*InitListSyntax*/IsListInit: false,
4596	/*IsInitListCopy*/true);
4597	return;
4598	}
4599	}
4600	if (const ArrayType *DestAT = S.Context.getAsArrayType(T: DestType)) {
4601	Expr *SubInit[1] = {InitList->getInit(Init: 0)};
4602	if (!isa<VariableArrayType>(Val: DestAT) &&
4603	IsStringInit(Init: SubInit[0], AT: DestAT, Context&: S.Context) == SIF_None) {
4604	InitializationKind SubKind =
4605	Kind.getKind() == InitializationKind::IK_DirectList
4606	? InitializationKind::CreateDirect(InitLoc: Kind.getLocation(),
4607	LParenLoc: InitList->getLBraceLoc(),
4608	RParenLoc: InitList->getRBraceLoc())
4609	: Kind;
4610	Sequence.InitializeFrom(S, Entity, Kind: SubKind, Args: SubInit,
4611	/*TopLevelOfInitList*/ true,
4612	TreatUnavailableAsInvalid);
4613
4614	// TryStringLiteralInitialization() (in InitializeFrom()) will fail if
4615	// the element is not an appropriately-typed string literal, in which
4616	// case we should proceed as in C++11 (below).
4617	if (Sequence) {
4618	Sequence.RewrapReferenceInitList(T: Entity.getType(), Syntactic: InitList);
4619	return;
4620	}
4621	}
4622	}
4623	}
4624
4625	// C++11 [dcl.init.list]p3:
4626	// - If T is an aggregate, aggregate initialization is performed.
4627	if ((DestType->isRecordType() && !DestType->isAggregateType()) ||
4628	(S.getLangOpts().CPlusPlus11 &&
4629	S.isStdInitializerList(Ty: DestType, Element: nullptr) && !IsDesignatedInit)) {
4630	if (S.getLangOpts().CPlusPlus11) {
4631	// - Otherwise, if the initializer list has no elements and T is a
4632	// class type with a default constructor, the object is
4633	// value-initialized.
4634	if (InitList->getNumInits() == 0) {
4635	CXXRecordDecl *RD = DestType->getAsCXXRecordDecl();
4636	if (S.LookupDefaultConstructor(Class: RD)) {
4637	TryValueInitialization(S, Entity, Kind, Sequence, InitList);
4638	return;
4639	}
4640	}
4641
4642	// - Otherwise, if T is a specialization of std::initializer_list<E>,
4643	// an initializer_list object constructed [...]
4644	if (TryInitializerListConstruction(S, List: InitList, DestType, Sequence,
4645	TreatUnavailableAsInvalid))
4646	return;
4647
4648	// - Otherwise, if T is a class type, constructors are considered.
4649	Expr *InitListAsExpr = InitList;
4650	TryConstructorInitialization(S, Entity, Kind, Args: InitListAsExpr, DestType,
4651	DestArrayType: DestType, Sequence, /*InitListSyntax*/IsListInit: true);
4652	} else
4653	Sequence.SetFailed(InitializationSequence::FK_InitListBadDestinationType);
4654	return;
4655	}
4656
4657	if (S.getLangOpts().CPlusPlus && !DestType->isAggregateType() &&
4658	InitList->getNumInits() == 1) {
4659	Expr *E = InitList->getInit(Init: 0);
4660
4661	// - Otherwise, if T is an enumeration with a fixed underlying type,
4662	// the initializer-list has a single element v, and the initialization
4663	// is direct-list-initialization, the object is initialized with the
4664	// value T(v); if a narrowing conversion is required to convert v to
4665	// the underlying type of T, the program is ill-formed.
4666	auto *ET = DestType->getAs<EnumType>();
4667	if (S.getLangOpts().CPlusPlus17 &&
4668	Kind.getKind() == InitializationKind::IK_DirectList &&
4669	ET && ET->getDecl()->isFixed() &&
4670	!S.Context.hasSameUnqualifiedType(T1: E->getType(), T2: DestType) &&
4671	(E->getType()->isIntegralOrUnscopedEnumerationType() ||
4672	E->getType()->isFloatingType())) {
4673	// There are two ways that T(v) can work when T is an enumeration type.
4674	// If there is either an implicit conversion sequence from v to T or
4675	// a conversion function that can convert from v to T, then we use that.
4676	// Otherwise, if v is of integral, unscoped enumeration, or floating-point
4677	// type, it is converted to the enumeration type via its underlying type.
4678	// There is no overlap possible between these two cases (except when the
4679	// source value is already of the destination type), and the first
4680	// case is handled by the general case for single-element lists below.
4681	ImplicitConversionSequence ICS;
4682	ICS.setStandard();
4683	ICS.Standard.setAsIdentityConversion();
4684	if (!E->isPRValue())
4685	ICS.Standard.First = ICK_Lvalue_To_Rvalue;
4686	// If E is of a floating-point type, then the conversion is ill-formed
4687	// due to narrowing, but go through the motions in order to produce the
4688	// right diagnostic.
4689	ICS.Standard.Second = E->getType()->isFloatingType()
4690	? ICK_Floating_Integral
4691	: ICK_Integral_Conversion;
4692	ICS.Standard.setFromType(E->getType());
4693	ICS.Standard.setToType(Idx: 0, T: E->getType());
4694	ICS.Standard.setToType(Idx: 1, T: DestType);
4695	ICS.Standard.setToType(Idx: 2, T: DestType);
4696	Sequence.AddConversionSequenceStep(ICS, T: ICS.Standard.getToType(Idx: 2),
4697	/*TopLevelOfInitList*/true);
4698	Sequence.RewrapReferenceInitList(T: Entity.getType(), Syntactic: InitList);
4699	return;
4700	}
4701
4702	// - Otherwise, if the initializer list has a single element of type E
4703	// [...references are handled above...], the object or reference is
4704	// initialized from that element (by copy-initialization for
4705	// copy-list-initialization, or by direct-initialization for
4706	// direct-list-initialization); if a narrowing conversion is required
4707	// to convert the element to T, the program is ill-formed.
4708	//
4709	// Per core-24034, this is direct-initialization if we were performing
4710	// direct-list-initialization and copy-initialization otherwise.
4711	// We can't use InitListChecker for this, because it always performs
4712	// copy-initialization. This only matters if we might use an 'explicit'
4713	// conversion operator, or for the special case conversion of nullptr_t to
4714	// bool, so we only need to handle those cases.
4715	//
4716	// FIXME: Why not do this in all cases?
4717	Expr *Init = InitList->getInit(Init: 0);
4718	if (Init->getType()->isRecordType() ||
4719	(Init->getType()->isNullPtrType() && DestType->isBooleanType())) {
4720	InitializationKind SubKind =
4721	Kind.getKind() == InitializationKind::IK_DirectList
4722	? InitializationKind::CreateDirect(InitLoc: Kind.getLocation(),
4723	LParenLoc: InitList->getLBraceLoc(),
4724	RParenLoc: InitList->getRBraceLoc())
4725	: Kind;
4726	Expr *SubInit[1] = { Init };
4727	Sequence.InitializeFrom(S, Entity, Kind: SubKind, Args: SubInit,
4728	/*TopLevelOfInitList*/true,
4729	TreatUnavailableAsInvalid);
4730	if (Sequence)
4731	Sequence.RewrapReferenceInitList(T: Entity.getType(), Syntactic: InitList);
4732	return;
4733	}
4734	}
4735
4736	InitListChecker CheckInitList(S, Entity, InitList,
4737	DestType, /*VerifyOnly=*/true, TreatUnavailableAsInvalid);
4738	if (CheckInitList.HadError()) {
4739	Sequence.SetFailed(InitializationSequence::FK_ListInitializationFailed);
4740	return;
4741	}
4742
4743	// Add the list initialization step with the built init list.
4744	Sequence.AddListInitializationStep(T: DestType);
4745	}
4746
4747	/// Try a reference initialization that involves calling a conversion
4748	/// function.
4749	static OverloadingResult TryRefInitWithConversionFunction(
4750	Sema &S, const InitializedEntity &Entity, const InitializationKind &Kind,
4751	Expr *Initializer, bool AllowRValues, bool IsLValueRef,
4752	InitializationSequence &Sequence) {
4753	QualType DestType = Entity.getType();
4754	QualType cv1T1 = DestType->castAs<ReferenceType>()->getPointeeType();
4755	QualType T1 = cv1T1.getUnqualifiedType();
4756	QualType cv2T2 = Initializer->getType();
4757	QualType T2 = cv2T2.getUnqualifiedType();
4758
4759	assert(!S.CompareReferenceRelationship(Initializer->getBeginLoc(), T1, T2) &&
4760	"Must have incompatible references when binding via conversion");
4761
4762	// Build the candidate set directly in the initialization sequence
4763	// structure, so that it will persist if we fail.
4764	OverloadCandidateSet &CandidateSet = Sequence.getFailedCandidateSet();
4765	CandidateSet.clear(CSK: OverloadCandidateSet::CSK_InitByUserDefinedConversion);
4766
4767	// Determine whether we are allowed to call explicit conversion operators.
4768	// Note that none of [over.match.copy], [over.match.conv], nor
4769	// [over.match.ref] permit an explicit constructor to be chosen when
4770	// initializing a reference, not even for direct-initialization.
4771	bool AllowExplicitCtors = false;
4772	bool AllowExplicitConvs = Kind.allowExplicitConversionFunctionsInRefBinding();
4773
4774	const RecordType *T1RecordType = nullptr;
4775	if (AllowRValues && (T1RecordType = T1->getAs<RecordType>()) &&
4776	S.isCompleteType(Loc: Kind.getLocation(), T: T1)) {
4777	// The type we're converting to is a class type. Enumerate its constructors
4778	// to see if there is a suitable conversion.
4779	CXXRecordDecl *T1RecordDecl = cast<CXXRecordDecl>(Val: T1RecordType->getDecl());
4780
4781	for (NamedDecl *D : S.LookupConstructors(Class: T1RecordDecl)) {
4782	auto Info = getConstructorInfo(ND: D);
4783	if (!Info.Constructor)
4784	continue;
4785
4786	if (!Info.Constructor->isInvalidDecl() &&
4787	Info.Constructor->isConvertingConstructor(/*AllowExplicit*/true)) {
4788	if (Info.ConstructorTmpl)
4789	S.AddTemplateOverloadCandidate(
4790	FunctionTemplate: Info.ConstructorTmpl, FoundDecl: Info.FoundDecl,
4791	/*ExplicitArgs*/ ExplicitTemplateArgs: nullptr, Args: Initializer, CandidateSet,
4792	/*SuppressUserConversions=*/true,
4793	/*PartialOverloading*/ false, AllowExplicit: AllowExplicitCtors);
4794	else
4795	S.AddOverloadCandidate(
4796	Info.Constructor, Info.FoundDecl, Initializer, CandidateSet,
4797	/*SuppressUserConversions=*/true,
4798	/*PartialOverloading*/ false, AllowExplicitCtors);
4799	}
4800	}
4801	}
4802	if (T1RecordType && T1RecordType->getDecl()->isInvalidDecl())
4803	return OR_No_Viable_Function;
4804
4805	const RecordType *T2RecordType = nullptr;
4806	if ((T2RecordType = T2->getAs<RecordType>()) &&
4807	S.isCompleteType(Loc: Kind.getLocation(), T: T2)) {
4808	// The type we're converting from is a class type, enumerate its conversion
4809	// functions.
4810	CXXRecordDecl *T2RecordDecl = cast<CXXRecordDecl>(Val: T2RecordType->getDecl());
4811
4812	const auto &Conversions = T2RecordDecl->getVisibleConversionFunctions();
4813	for (auto I = Conversions.begin(), E = Conversions.end(); I != E; ++I) {
4814	NamedDecl *D = *I;
4815	CXXRecordDecl *ActingDC = cast<CXXRecordDecl>(D->getDeclContext());
4816	if (isa<UsingShadowDecl>(Val: D))
4817	D = cast<UsingShadowDecl>(Val: D)->getTargetDecl();
4818
4819	FunctionTemplateDecl *ConvTemplate = dyn_cast<FunctionTemplateDecl>(Val: D);
4820	CXXConversionDecl *Conv;
4821	if (ConvTemplate)
4822	Conv = cast<CXXConversionDecl>(Val: ConvTemplate->getTemplatedDecl());
4823	else
4824	Conv = cast<CXXConversionDecl>(Val: D);
4825
4826	// If the conversion function doesn't return a reference type,
4827	// it can't be considered for this conversion unless we're allowed to
4828	// consider rvalues.
4829	// FIXME: Do we need to make sure that we only consider conversion
4830	// candidates with reference-compatible results? That might be needed to
4831	// break recursion.
4832	if ((AllowRValues ||
4833	Conv->getConversionType()->isLValueReferenceType())) {
4834	if (ConvTemplate)
4835	S.AddTemplateConversionCandidate(
4836	FunctionTemplate: ConvTemplate, FoundDecl: I.getPair(), ActingContext: ActingDC, From: Initializer, ToType: DestType,
4837	CandidateSet,
4838	/*AllowObjCConversionOnExplicit=*/false, AllowExplicit: AllowExplicitConvs);
4839	else
4840	S.AddConversionCandidate(
4841	Conversion: Conv, FoundDecl: I.getPair(), ActingContext: ActingDC, From: Initializer, ToType: DestType, CandidateSet,
4842	/*AllowObjCConversionOnExplicit=*/false, AllowExplicit: AllowExplicitConvs);
4843	}
4844	}
4845	}
4846	if (T2RecordType && T2RecordType->getDecl()->isInvalidDecl())
4847	return OR_No_Viable_Function;
4848
4849	SourceLocation DeclLoc = Initializer->getBeginLoc();
4850
4851	// Perform overload resolution. If it fails, return the failed result.
4852	OverloadCandidateSet::iterator Best;
4853	if (OverloadingResult Result
4854	= CandidateSet.BestViableFunction(S, Loc: DeclLoc, Best))
4855	return Result;
4856
4857	FunctionDecl *Function = Best->Function;
4858	// This is the overload that will be used for this initialization step if we
4859	// use this initialization. Mark it as referenced.
4860	Function->setReferenced();
4861
4862	// Compute the returned type and value kind of the conversion.
4863	QualType cv3T3;
4864	if (isa<CXXConversionDecl>(Val: Function))
4865	cv3T3 = Function->getReturnType();
4866	else
4867	cv3T3 = T1;
4868
4869	ExprValueKind VK = VK_PRValue;
4870	if (cv3T3->isLValueReferenceType())
4871	VK = VK_LValue;
4872	else if (const auto *RRef = cv3T3->getAs<RValueReferenceType>())
4873	VK = RRef->getPointeeType()->isFunctionType() ? VK_LValue : VK_XValue;
4874	cv3T3 = cv3T3.getNonLValueExprType(Context: S.Context);
4875
4876	// Add the user-defined conversion step.
4877	bool HadMultipleCandidates = (CandidateSet.size() > 1);
4878	Sequence.AddUserConversionStep(Function, FoundDecl: Best->FoundDecl, T: cv3T3,
4879	HadMultipleCandidates);
4880
4881	// Determine whether we'll need to perform derived-to-base adjustments or
4882	// other conversions.
4883	Sema::ReferenceConversions RefConv;
4884	Sema::ReferenceCompareResult NewRefRelationship =
4885	S.CompareReferenceRelationship(Loc: DeclLoc, T1, T2: cv3T3, Conv: &RefConv);
4886
4887	// Add the final conversion sequence, if necessary.
4888	if (NewRefRelationship == Sema::Ref_Incompatible) {
4889	assert(!isa<CXXConstructorDecl>(Function) &&
4890	"should not have conversion after constructor");
4891
4892	ImplicitConversionSequence ICS;
4893	ICS.setStandard();
4894	ICS.Standard = Best->FinalConversion;
4895	Sequence.AddConversionSequenceStep(ICS, T: ICS.Standard.getToType(Idx: 2));
4896
4897	// Every implicit conversion results in a prvalue, except for a glvalue
4898	// derived-to-base conversion, which we handle below.
4899	cv3T3 = ICS.Standard.getToType(Idx: 2);
4900	VK = VK_PRValue;
4901	}
4902
4903	// If the converted initializer is a prvalue, its type T4 is adjusted to
4904	// type "cv1 T4" and the temporary materialization conversion is applied.
4905	//
4906	// We adjust the cv-qualifications to match the reference regardless of
4907	// whether we have a prvalue so that the AST records the change. In this
4908	// case, T4 is "cv3 T3".
4909	QualType cv1T4 = S.Context.getQualifiedType(T: cv3T3, Qs: cv1T1.getQualifiers());
4910	if (cv1T4.getQualifiers() != cv3T3.getQualifiers())
4911	Sequence.AddQualificationConversionStep(Ty: cv1T4, VK);
4912	Sequence.AddReferenceBindingStep(T: cv1T4, BindingTemporary: VK == VK_PRValue);
4913	VK = IsLValueRef ? VK_LValue : VK_XValue;
4914
4915	if (RefConv & Sema::ReferenceConversions::DerivedToBase)
4916	Sequence.AddDerivedToBaseCastStep(BaseType: cv1T1, VK);
4917	else if (RefConv & Sema::ReferenceConversions::ObjC)
4918	Sequence.AddObjCObjectConversionStep(T: cv1T1);
4919	else if (RefConv & Sema::ReferenceConversions::Function)
4920	Sequence.AddFunctionReferenceConversionStep(Ty: cv1T1);
4921	else if (RefConv & Sema::ReferenceConversions::Qualification) {
4922	if (!S.Context.hasSameType(T1: cv1T4, T2: cv1T1))
4923	Sequence.AddQualificationConversionStep(Ty: cv1T1, VK);
4924	}
4925
4926	return OR_Success;
4927	}
4928
4929	static void CheckCXX98CompatAccessibleCopy(Sema &S,
4930	const InitializedEntity &Entity,
4931	Expr *CurInitExpr);
4932
4933	/// Attempt reference initialization (C++0x [dcl.init.ref])
4934	static void TryReferenceInitialization(Sema &S, const InitializedEntity &Entity,
4935	const InitializationKind &Kind,
4936	Expr *Initializer,
4937	InitializationSequence &Sequence,
4938	bool TopLevelOfInitList) {
4939	QualType DestType = Entity.getType();
4940	QualType cv1T1 = DestType->castAs<ReferenceType>()->getPointeeType();
4941	Qualifiers T1Quals;
4942	QualType T1 = S.Context.getUnqualifiedArrayType(T: cv1T1, Quals&: T1Quals);
4943	QualType cv2T2 = S.getCompletedType(E: Initializer);
4944	Qualifiers T2Quals;
4945	QualType T2 = S.Context.getUnqualifiedArrayType(T: cv2T2, Quals&: T2Quals);
4946
4947	// If the initializer is the address of an overloaded function, try
4948	// to resolve the overloaded function. If all goes well, T2 is the
4949	// type of the resulting function.
4950	if (ResolveOverloadedFunctionForReferenceBinding(S, Initializer, SourceType&: cv2T2, UnqualifiedSourceType&: T2,
4951	UnqualifiedTargetType: T1, Sequence))
4952	return;
4953
4954	// Delegate everything else to a subfunction.
4955	TryReferenceInitializationCore(S, Entity, Kind, Initializer, cv1T1, T1,
4956	T1Quals, cv2T2, T2, T2Quals, Sequence,
4957	TopLevelOfInitList);
4958	}
4959
4960	/// Determine whether an expression is a non-referenceable glvalue (one to
4961	/// which a reference can never bind). Attempting to bind a reference to
4962	/// such a glvalue will always create a temporary.
4963	static bool isNonReferenceableGLValue(Expr *E) {
4964	return E->refersToBitField() || E->refersToVectorElement() ||
4965	E->refersToMatrixElement();
4966	}
4967
4968	/// Reference initialization without resolving overloaded functions.
4969	///
4970	/// We also can get here in C if we call a builtin which is declared as
4971	/// a function with a parameter of reference type (such as __builtin_va_end()).
4972	static void TryReferenceInitializationCore(Sema &S,
4973	const InitializedEntity &Entity,
4974	const InitializationKind &Kind,
4975	Expr *Initializer,
4976	QualType cv1T1, QualType T1,
4977	Qualifiers T1Quals,
4978	QualType cv2T2, QualType T2,
4979	Qualifiers T2Quals,
4980	InitializationSequence &Sequence,
4981	bool TopLevelOfInitList) {
4982	QualType DestType = Entity.getType();
4983	SourceLocation DeclLoc = Initializer->getBeginLoc();
4984
4985	// Compute some basic properties of the types and the initializer.
4986	bool isLValueRef = DestType->isLValueReferenceType();
4987	bool isRValueRef = !isLValueRef;
4988	Expr::Classification InitCategory = Initializer->Classify(Ctx&: S.Context);
4989
4990	Sema::ReferenceConversions RefConv;
4991	Sema::ReferenceCompareResult RefRelationship =
4992	S.CompareReferenceRelationship(Loc: DeclLoc, T1: cv1T1, T2: cv2T2, Conv: &RefConv);
4993
4994	// C++0x [dcl.init.ref]p5:
4995	// A reference to type "cv1 T1" is initialized by an expression of type
4996	// "cv2 T2" as follows:
4997	//
4998	// - If the reference is an lvalue reference and the initializer
4999	// expression
5000	// Note the analogous bullet points for rvalue refs to functions. Because
5001	// there are no function rvalues in C++, rvalue refs to functions are treated
5002	// like lvalue refs.
5003	OverloadingResult ConvOvlResult = OR_Success;
5004	bool T1Function = T1->isFunctionType();
5005	if (isLValueRef || T1Function) {
5006	if (InitCategory.isLValue() && !isNonReferenceableGLValue(E: Initializer) &&
5007	(RefRelationship == Sema::Ref_Compatible ||
5008	(Kind.isCStyleOrFunctionalCast() &&
5009	RefRelationship == Sema::Ref_Related))) {
5010	// - is an lvalue (but is not a bit-field), and "cv1 T1" is
5011	// reference-compatible with "cv2 T2," or
5012	if (RefConv & (Sema::ReferenceConversions::DerivedToBase |
5013	Sema::ReferenceConversions::ObjC)) {
5014	// If we're converting the pointee, add any qualifiers first;
5015	// these qualifiers must all be top-level, so just convert to "cv1 T2".
5016	if (RefConv & (Sema::ReferenceConversions::Qualification))
5017	Sequence.AddQualificationConversionStep(
5018	Ty: S.Context.getQualifiedType(T: T2, Qs: T1Quals),
5019	VK: Initializer->getValueKind());
5020	if (RefConv & Sema::ReferenceConversions::DerivedToBase)
5021	Sequence.AddDerivedToBaseCastStep(BaseType: cv1T1, VK: VK_LValue);
5022	else
5023	Sequence.AddObjCObjectConversionStep(T: cv1T1);
5024	} else if (RefConv & Sema::ReferenceConversions::Qualification) {
5025	// Perform a (possibly multi-level) qualification conversion.
5026	Sequence.AddQualificationConversionStep(Ty: cv1T1,
5027	VK: Initializer->getValueKind());
5028	} else if (RefConv & Sema::ReferenceConversions::Function) {
5029	Sequence.AddFunctionReferenceConversionStep(Ty: cv1T1);
5030	}
5031
5032	// We only create a temporary here when binding a reference to a
5033	// bit-field or vector element. Those cases are't supposed to be
5034	// handled by this bullet, but the outcome is the same either way.
5035	Sequence.AddReferenceBindingStep(T: cv1T1, BindingTemporary: false);
5036	return;
5037	}
5038
5039	// - has a class type (i.e., T2 is a class type), where T1 is not
5040	// reference-related to T2, and can be implicitly converted to an
5041	// lvalue of type "cv3 T3," where "cv1 T1" is reference-compatible
5042	// with "cv3 T3" (this conversion is selected by enumerating the
5043	// applicable conversion functions (13.3.1.6) and choosing the best
5044	// one through overload resolution (13.3)),
5045	// If we have an rvalue ref to function type here, the rhs must be
5046	// an rvalue. DR1287 removed the "implicitly" here.
5047	if (RefRelationship == Sema::Ref_Incompatible && T2->isRecordType() &&
5048	(isLValueRef || InitCategory.isRValue())) {
5049	if (S.getLangOpts().CPlusPlus) {
5050	// Try conversion functions only for C++.
5051	ConvOvlResult = TryRefInitWithConversionFunction(
5052	S, Entity, Kind, Initializer, /*AllowRValues*/ isRValueRef,
5053	/*IsLValueRef*/ isLValueRef, Sequence);
5054	if (ConvOvlResult == OR_Success)
5055	return;
5056	if (ConvOvlResult != OR_No_Viable_Function)
5057	Sequence.SetOverloadFailure(
5058	Failure: InitializationSequence::FK_ReferenceInitOverloadFailed,
5059	Result: ConvOvlResult);
5060	} else {
5061	ConvOvlResult = OR_No_Viable_Function;
5062	}
5063	}
5064	}
5065
5066	// - Otherwise, the reference shall be an lvalue reference to a
5067	// non-volatile const type (i.e., cv1 shall be const), or the reference
5068	// shall be an rvalue reference.
5069	// For address spaces, we interpret this to mean that an addr space
5070	// of a reference "cv1 T1" is a superset of addr space of "cv2 T2".
5071	if (isLValueRef && !(T1Quals.hasConst() && !T1Quals.hasVolatile() &&
5072	T1Quals.isAddressSpaceSupersetOf(other: T2Quals))) {
5073	if (S.Context.getCanonicalType(T: T2) == S.Context.OverloadTy)
5074	Sequence.SetFailed(InitializationSequence::FK_AddressOfOverloadFailed);
5075	else if (ConvOvlResult && !Sequence.getFailedCandidateSet().empty())
5076	Sequence.SetOverloadFailure(
5077	Failure: InitializationSequence::FK_ReferenceInitOverloadFailed,
5078	Result: ConvOvlResult);
5079	else if (!InitCategory.isLValue())
5080	Sequence.SetFailed(
5081	T1Quals.isAddressSpaceSupersetOf(other: T2Quals)
5082	? InitializationSequence::
5083	FK_NonConstLValueReferenceBindingToTemporary
5084	: InitializationSequence::FK_ReferenceInitDropsQualifiers);
5085	else {
5086	InitializationSequence::FailureKind FK;
5087	switch (RefRelationship) {
5088	case Sema::Ref_Compatible:
5089	if (Initializer->refersToBitField())
5090	FK = InitializationSequence::
5091	FK_NonConstLValueReferenceBindingToBitfield;
5092	else if (Initializer->refersToVectorElement())
5093	FK = InitializationSequence::
5094	FK_NonConstLValueReferenceBindingToVectorElement;
5095	else if (Initializer->refersToMatrixElement())
5096	FK = InitializationSequence::
5097	FK_NonConstLValueReferenceBindingToMatrixElement;
5098	else
5099	llvm_unreachable("unexpected kind of compatible initializer");
5100	break;
5101	case Sema::Ref_Related:
5102	FK = InitializationSequence::FK_ReferenceInitDropsQualifiers;
5103	break;
5104	case Sema::Ref_Incompatible:
5105	FK = InitializationSequence::
5106	FK_NonConstLValueReferenceBindingToUnrelated;
5107	break;
5108	}
5109	Sequence.SetFailed(FK);
5110	}
5111	return;
5112	}
5113
5114	// - If the initializer expression
5115	// - is an
5116	// [<=14] xvalue (but not a bit-field), class prvalue, array prvalue, or
5117	// [1z] rvalue (but not a bit-field) or
5118	// function lvalue and "cv1 T1" is reference-compatible with "cv2 T2"
5119	//
5120	// Note: functions are handled above and below rather than here...
5121	if (!T1Function &&
5122	(RefRelationship == Sema::Ref_Compatible ||
5123	(Kind.isCStyleOrFunctionalCast() &&
5124	RefRelationship == Sema::Ref_Related)) &&
5125	((InitCategory.isXValue() && !isNonReferenceableGLValue(E: Initializer)) ||
5126	(InitCategory.isPRValue() &&
5127	(S.getLangOpts().CPlusPlus17 || T2->isRecordType() ||
5128	T2->isArrayType())))) {
5129	ExprValueKind ValueKind = InitCategory.isXValue() ? VK_XValue : VK_PRValue;
5130	if (InitCategory.isPRValue() && T2->isRecordType()) {
5131	// The corresponding bullet in C++03 [dcl.init.ref]p5 gives the
5132	// compiler the freedom to perform a copy here or bind to the
5133	// object, while C++0x requires that we bind directly to the
5134	// object. Hence, we always bind to the object without making an
5135	// extra copy. However, in C++03 requires that we check for the
5136	// presence of a suitable copy constructor:
5137	//
5138	// The constructor that would be used to make the copy shall
5139	// be callable whether or not the copy is actually done.
5140	if (!S.getLangOpts().CPlusPlus11 && !S.getLangOpts().MicrosoftExt)
5141	Sequence.AddExtraneousCopyToTemporary(T: cv2T2);
5142	else if (S.getLangOpts().CPlusPlus11)
5143	CheckCXX98CompatAccessibleCopy(S, Entity, CurInitExpr: Initializer);
5144	}
5145
5146	// C++1z [dcl.init.ref]/5.2.1.2:
5147	// If the converted initializer is a prvalue, its type T4 is adjusted
5148	// to type "cv1 T4" and the temporary materialization conversion is
5149	// applied.
5150	// Postpone address space conversions to after the temporary materialization
5151	// conversion to allow creating temporaries in the alloca address space.
5152	auto T1QualsIgnoreAS = T1Quals;
5153	auto T2QualsIgnoreAS = T2Quals;
5154	if (T1Quals.getAddressSpace() != T2Quals.getAddressSpace()) {
5155	T1QualsIgnoreAS.removeAddressSpace();
5156	T2QualsIgnoreAS.removeAddressSpace();
5157	}
5158	QualType cv1T4 = S.Context.getQualifiedType(T: cv2T2, Qs: T1QualsIgnoreAS);
5159	if (T1QualsIgnoreAS != T2QualsIgnoreAS)
5160	Sequence.AddQualificationConversionStep(Ty: cv1T4, VK: ValueKind);
5161	Sequence.AddReferenceBindingStep(T: cv1T4, BindingTemporary: ValueKind == VK_PRValue);
5162	ValueKind = isLValueRef ? VK_LValue : VK_XValue;
5163	// Add addr space conversion if required.
5164	if (T1Quals.getAddressSpace() != T2Quals.getAddressSpace()) {
5165	auto T4Quals = cv1T4.getQualifiers();
5166	T4Quals.addAddressSpace(space: T1Quals.getAddressSpace());
5167	QualType cv1T4WithAS = S.Context.getQualifiedType(T: T2, Qs: T4Quals);
5168	Sequence.AddQualificationConversionStep(Ty: cv1T4WithAS, VK: ValueKind);
5169	cv1T4 = cv1T4WithAS;
5170	}
5171
5172	// In any case, the reference is bound to the resulting glvalue (or to
5173	// an appropriate base class subobject).
5174	if (RefConv & Sema::ReferenceConversions::DerivedToBase)
5175	Sequence.AddDerivedToBaseCastStep(BaseType: cv1T1, VK: ValueKind);
5176	else if (RefConv & Sema::ReferenceConversions::ObjC)
5177	Sequence.AddObjCObjectConversionStep(T: cv1T1);
5178	else if (RefConv & Sema::ReferenceConversions::Qualification) {
5179	if (!S.Context.hasSameType(T1: cv1T4, T2: cv1T1))
5180	Sequence.AddQualificationConversionStep(Ty: cv1T1, VK: ValueKind);
5181	}
5182	return;
5183	}
5184
5185	// - has a class type (i.e., T2 is a class type), where T1 is not
5186	// reference-related to T2, and can be implicitly converted to an
5187	// xvalue, class prvalue, or function lvalue of type "cv3 T3",
5188	// where "cv1 T1" is reference-compatible with "cv3 T3",
5189	//
5190	// DR1287 removes the "implicitly" here.
5191	if (T2->isRecordType()) {
5192	if (RefRelationship == Sema::Ref_Incompatible) {
5193	ConvOvlResult = TryRefInitWithConversionFunction(
5194	S, Entity, Kind, Initializer, /*AllowRValues*/ true,
5195	/*IsLValueRef*/ isLValueRef, Sequence);
5196	if (ConvOvlResult)
5197	Sequence.SetOverloadFailure(
5198	Failure: InitializationSequence::FK_ReferenceInitOverloadFailed,
5199	Result: ConvOvlResult);
5200
5201	return;
5202	}
5203
5204	if (RefRelationship == Sema::Ref_Compatible &&
5205	isRValueRef && InitCategory.isLValue()) {
5206	Sequence.SetFailed(
5207	InitializationSequence::FK_RValueReferenceBindingToLValue);
5208	return;
5209	}
5210
5211	Sequence.SetFailed(InitializationSequence::FK_ReferenceInitDropsQualifiers);
5212	return;
5213	}
5214
5215	// - Otherwise, a temporary of type "cv1 T1" is created and initialized
5216	// from the initializer expression using the rules for a non-reference
5217	// copy-initialization (8.5). The reference is then bound to the
5218	// temporary. [...]
5219
5220	// Ignore address space of reference type at this point and perform address
5221	// space conversion after the reference binding step.
5222	QualType cv1T1IgnoreAS =
5223	T1Quals.hasAddressSpace()
5224	? S.Context.getQualifiedType(T: T1, Qs: T1Quals.withoutAddressSpace())
5225	: cv1T1;
5226
5227	InitializedEntity TempEntity =
5228	InitializedEntity::InitializeTemporary(Type: cv1T1IgnoreAS);
5229
5230	// FIXME: Why do we use an implicit conversion here rather than trying
5231	// copy-initialization?
5232	ImplicitConversionSequence ICS
5233	= S.TryImplicitConversion(From: Initializer, ToType: TempEntity.getType(),
5234	/*SuppressUserConversions=*/false,
5235	AllowExplicit: Sema::AllowedExplicit::None,
5236	/*FIXME:InOverloadResolution=*/InOverloadResolution: false,
5237	/*CStyle=*/Kind.isCStyleOrFunctionalCast(),
5238	/*AllowObjCWritebackConversion=*/false);
5239
5240	if (ICS.isBad()) {
5241	// FIXME: Use the conversion function set stored in ICS to turn
5242	// this into an overloading ambiguity diagnostic. However, we need
5243	// to keep that set as an OverloadCandidateSet rather than as some
5244	// other kind of set.
5245	if (ConvOvlResult && !Sequence.getFailedCandidateSet().empty())
5246	Sequence.SetOverloadFailure(
5247	Failure: InitializationSequence::FK_ReferenceInitOverloadFailed,
5248	Result: ConvOvlResult);
5249	else if (S.Context.getCanonicalType(T: T2) == S.Context.OverloadTy)
5250	Sequence.SetFailed(InitializationSequence::FK_AddressOfOverloadFailed);
5251	else
5252	Sequence.SetFailed(InitializationSequence::FK_ReferenceInitFailed);
5253	return;
5254	} else {
5255	Sequence.AddConversionSequenceStep(ICS, T: TempEntity.getType(),
5256	TopLevelOfInitList);
5257	}
5258
5259	// [...] If T1 is reference-related to T2, cv1 must be the
5260	// same cv-qualification as, or greater cv-qualification
5261	// than, cv2; otherwise, the program is ill-formed.
5262	unsigned T1CVRQuals = T1Quals.getCVRQualifiers();
5263	unsigned T2CVRQuals = T2Quals.getCVRQualifiers();
5264	if (RefRelationship == Sema::Ref_Related &&
5265	((T1CVRQuals | T2CVRQuals) != T1CVRQuals ||
5266	!T1Quals.isAddressSpaceSupersetOf(other: T2Quals))) {
5267	Sequence.SetFailed(InitializationSequence::FK_ReferenceInitDropsQualifiers);
5268	return;
5269	}
5270
5271	// [...] If T1 is reference-related to T2 and the reference is an rvalue
5272	// reference, the initializer expression shall not be an lvalue.
5273	if (RefRelationship >= Sema::Ref_Related && !isLValueRef &&
5274	InitCategory.isLValue()) {
5275	Sequence.SetFailed(
5276	InitializationSequence::FK_RValueReferenceBindingToLValue);
5277	return;
5278	}
5279
5280	Sequence.AddReferenceBindingStep(T: cv1T1IgnoreAS, /*BindingTemporary=*/true);
5281
5282	if (T1Quals.hasAddressSpace()) {
5283	if (!Qualifiers::isAddressSpaceSupersetOf(A: T1Quals.getAddressSpace(),
5284	B: LangAS::Default)) {
5285	Sequence.SetFailed(
5286	InitializationSequence::FK_ReferenceAddrspaceMismatchTemporary);
5287	return;
5288	}
5289	Sequence.AddQualificationConversionStep(Ty: cv1T1, VK: isLValueRef ? VK_LValue
5290	: VK_XValue);
5291	}
5292	}
5293
5294	/// Attempt character array initialization from a string literal
5295	/// (C++ [dcl.init.string], C99 6.7.8).
5296	static void TryStringLiteralInitialization(Sema &S,
5297	const InitializedEntity &Entity,
5298	const InitializationKind &Kind,
5299	Expr *Initializer,
5300	InitializationSequence &Sequence) {
5301	Sequence.AddStringInitStep(T: Entity.getType());
5302	}
5303
5304	/// Attempt value initialization (C++ [dcl.init]p7).
5305	static void TryValueInitialization(Sema &S,
5306	const InitializedEntity &Entity,
5307	const InitializationKind &Kind,
5308	InitializationSequence &Sequence,
5309	InitListExpr *InitList) {
5310	assert((!InitList || InitList->getNumInits() == 0) &&
5311	"Shouldn't use value-init for non-empty init lists");
5312
5313	// C++98 [dcl.init]p5, C++11 [dcl.init]p7:
5314	//
5315	// To value-initialize an object of type T means:
5316	QualType T = Entity.getType();
5317
5318	// -- if T is an array type, then each element is value-initialized;
5319	T = S.Context.getBaseElementType(QT: T);
5320
5321	if (const RecordType *RT = T->getAs<RecordType>()) {
5322	if (CXXRecordDecl *ClassDecl = dyn_cast<CXXRecordDecl>(Val: RT->getDecl())) {
5323	bool NeedZeroInitialization = true;
5324	// C++98:
5325	// -- if T is a class type (clause 9) with a user-declared constructor
5326	// (12.1), then the default constructor for T is called (and the
5327	// initialization is ill-formed if T has no accessible default
5328	// constructor);
5329	// C++11:
5330	// -- if T is a class type (clause 9) with either no default constructor
5331	// (12.1 [class.ctor]) or a default constructor that is user-provided
5332	// or deleted, then the object is default-initialized;
5333	//
5334	// Note that the C++11 rule is the same as the C++98 rule if there are no
5335	// defaulted or deleted constructors, so we just use it unconditionally.
5336	CXXConstructorDecl *CD = S.LookupDefaultConstructor(Class: ClassDecl);
5337	if (!CD || !CD->getCanonicalDecl()->isDefaulted() || CD->isDeleted())
5338	NeedZeroInitialization = false;
5339
5340	// -- if T is a (possibly cv-qualified) non-union class type without a
5341	// user-provided or deleted default constructor, then the object is
5342	// zero-initialized and, if T has a non-trivial default constructor,
5343	// default-initialized;
5344	// The 'non-union' here was removed by DR1502. The 'non-trivial default
5345	// constructor' part was removed by DR1507.
5346	if (NeedZeroInitialization)
5347	Sequence.AddZeroInitializationStep(T: Entity.getType());
5348
5349	// C++03:
5350	// -- if T is a non-union class type without a user-declared constructor,
5351	// then every non-static data member and base class component of T is
5352	// value-initialized;
5353	// [...] A program that calls for [...] value-initialization of an
5354	// entity of reference type is ill-formed.
5355	//
5356	// C++11 doesn't need this handling, because value-initialization does not
5357	// occur recursively there, and the implicit default constructor is
5358	// defined as deleted in the problematic cases.
5359	if (!S.getLangOpts().CPlusPlus11 &&
5360	ClassDecl->hasUninitializedReferenceMember()) {
5361	Sequence.SetFailed(InitializationSequence::FK_TooManyInitsForReference);
5362	return;
5363	}
5364
5365	// If this is list-value-initialization, pass the empty init list on when
5366	// building the constructor call. This affects the semantics of a few
5367	// things (such as whether an explicit default constructor can be called).
5368	Expr *InitListAsExpr = InitList;
5369	MultiExprArg Args(&InitListAsExpr, InitList ? 1 : 0);
5370	bool InitListSyntax = InitList;
5371
5372	// FIXME: Instead of creating a CXXConstructExpr of array type here,
5373	// wrap a class-typed CXXConstructExpr in an ArrayInitLoopExpr.
5374	return TryConstructorInitialization(
5375	S, Entity, Kind, Args, DestType: T, DestArrayType: Entity.getType(), Sequence, IsListInit: InitListSyntax);
5376	}
5377	}
5378
5379	Sequence.AddZeroInitializationStep(T: Entity.getType());
5380	}
5381
5382	/// Attempt default initialization (C++ [dcl.init]p6).
5383	static void TryDefaultInitialization(Sema &S,
5384	const InitializedEntity &Entity,
5385	const InitializationKind &Kind,
5386	InitializationSequence &Sequence) {
5387	assert(Kind.getKind() == InitializationKind::IK_Default);
5388
5389	// C++ [dcl.init]p6:
5390	// To default-initialize an object of type T means:
5391	// - if T is an array type, each element is default-initialized;
5392	QualType DestType = S.Context.getBaseElementType(QT: Entity.getType());
5393
5394	// - if T is a (possibly cv-qualified) class type (Clause 9), the default
5395	// constructor for T is called (and the initialization is ill-formed if
5396	// T has no accessible default constructor);
5397	if (DestType->isRecordType() && S.getLangOpts().CPlusPlus) {
5398	TryConstructorInitialization(S, Entity, Kind, Args: std::nullopt, DestType,
5399	DestArrayType: Entity.getType(), Sequence);
5400	return;
5401	}
5402
5403	// - otherwise, no initialization is performed.
5404
5405	// If a program calls for the default initialization of an object of
5406	// a const-qualified type T, T shall be a class type with a user-provided
5407	// default constructor.
5408	if (DestType.isConstQualified() && S.getLangOpts().CPlusPlus) {
5409	if (!maybeRecoverWithZeroInitialization(S, Sequence, Entity))
5410	Sequence.SetFailed(InitializationSequence::FK_DefaultInitOfConst);
5411	return;
5412	}
5413
5414	// If the destination type has a lifetime property, zero-initialize it.
5415	if (DestType.getQualifiers().hasObjCLifetime()) {
5416	Sequence.AddZeroInitializationStep(T: Entity.getType());
5417	return;
5418	}
5419	}
5420
5421	static void TryOrBuildParenListInitialization(
5422	Sema &S, const InitializedEntity &Entity, const InitializationKind &Kind,
5423	ArrayRef<Expr *> Args, InitializationSequence &Sequence, bool VerifyOnly,
5424	ExprResult *Result = nullptr) {
5425	unsigned EntityIndexToProcess = 0;
5426	SmallVector<Expr *, 4> InitExprs;
5427	QualType ResultType;
5428	Expr *ArrayFiller = nullptr;
5429	FieldDecl *InitializedFieldInUnion = nullptr;
5430
5431	auto HandleInitializedEntity = [&](const InitializedEntity &SubEntity,
5432	const InitializationKind &SubKind,
5433	Expr *Arg, Expr **InitExpr = nullptr) {
5434	InitializationSequence IS = InitializationSequence(
5435	S, SubEntity, SubKind, Arg ? MultiExprArg(Arg) : std::nullopt);
5436
5437	if (IS.Failed()) {
5438	if (!VerifyOnly) {
5439	IS.Diagnose(S, Entity: SubEntity, Kind: SubKind, Args: Arg ? ArrayRef(Arg) : std::nullopt);
5440	} else {
5441	Sequence.SetFailed(
5442	InitializationSequence::FK_ParenthesizedListInitFailed);
5443	}
5444
5445	return false;
5446	}
5447	if (!VerifyOnly) {
5448	ExprResult ER;
5449	ER = IS.Perform(S, Entity: SubEntity, Kind: SubKind,
5450	Args: Arg ? MultiExprArg(Arg) : std::nullopt);
5451	if (InitExpr)
5452	*InitExpr = ER.get();
5453	else
5454	InitExprs.push_back(Elt: ER.get());
5455	}
5456	return true;
5457	};
5458
5459	if (const ArrayType *AT =
5460	S.getASTContext().getAsArrayType(T: Entity.getType())) {
5461	SmallVector<InitializedEntity, 4> ElementEntities;
5462	uint64_t ArrayLength;
5463	// C++ [dcl.init]p16.5
5464	// if the destination type is an array, the object is initialized as
5465	// follows. Let x1, . . . , xk be the elements of the expression-list. If
5466	// the destination type is an array of unknown bound, it is defined as
5467	// having k elements.
5468	if (const ConstantArrayType *CAT =
5469	S.getASTContext().getAsConstantArrayType(T: Entity.getType())) {
5470	ArrayLength = CAT->getSize().getZExtValue();
5471	ResultType = Entity.getType();
5472	} else if (const VariableArrayType *VAT =
5473	S.getASTContext().getAsVariableArrayType(T: Entity.getType())) {
5474	// Braced-initialization of variable array types is not allowed, even if
5475	// the size is greater than or equal to the number of args, so we don't
5476	// allow them to be initialized via parenthesized aggregate initialization
5477	// either.
5478	const Expr *SE = VAT->getSizeExpr();
5479	S.Diag(SE->getBeginLoc(), diag::err_variable_object_no_init)
5480	<< SE->getSourceRange();
5481	return;
5482	} else {
5483	assert(isa<IncompleteArrayType>(Entity.getType()));
5484	ArrayLength = Args.size();
5485	}
5486	EntityIndexToProcess = ArrayLength;
5487
5488	// ...the ith array element is copy-initialized with xi for each
5489	// 1 <= i <= k
5490	for (Expr *E : Args) {
5491	InitializedEntity SubEntity = InitializedEntity::InitializeElement(
5492	Context&: S.getASTContext(), Index: EntityIndexToProcess, Parent: Entity);
5493	InitializationKind SubKind = InitializationKind::CreateForInit(
5494	Loc: E->getExprLoc(), /*isDirectInit=*/DirectInit: false, Init: E);
5495	if (!HandleInitializedEntity(SubEntity, SubKind, E))
5496	return;
5497	}
5498	// ...and value-initialized for each k < i <= n;
5499	if (ArrayLength > Args.size() || Entity.isVariableLengthArrayNew()) {
5500	InitializedEntity SubEntity = InitializedEntity::InitializeElement(
5501	Context&: S.getASTContext(), Index: Args.size(), Parent: Entity);
5502	InitializationKind SubKind = InitializationKind::CreateValue(
5503	InitLoc: Kind.getLocation(), LParenLoc: Kind.getLocation(), RParenLoc: Kind.getLocation(), isImplicit: true);
5504	if (!HandleInitializedEntity(SubEntity, SubKind, nullptr, &ArrayFiller))
5505	return;
5506	}
5507
5508	if (ResultType.isNull()) {
5509	ResultType = S.Context.getConstantArrayType(
5510	EltTy: AT->getElementType(), ArySize: llvm::APInt(/*numBits=*/32, ArrayLength),
5511	/*SizeExpr=*/nullptr, ASM: ArraySizeModifier::Normal, IndexTypeQuals: 0);
5512	}
5513	} else if (auto *RT = Entity.getType()->getAs<RecordType>()) {
5514	bool IsUnion = RT->isUnionType();
5515	const CXXRecordDecl *RD = cast<CXXRecordDecl>(Val: RT->getDecl());
5516	if (RD->isInvalidDecl()) {
5517	// Exit early to avoid confusion when processing members.
5518	// We do the same for braced list initialization in
5519	// `CheckStructUnionTypes`.
5520	Sequence.SetFailed(
5521	clang::InitializationSequence::FK_ParenthesizedListInitFailed);
5522	return;
5523	}
5524
5525	if (!IsUnion) {
5526	for (const CXXBaseSpecifier &Base : RD->bases()) {
5527	InitializedEntity SubEntity = InitializedEntity::InitializeBase(
5528	Context&: S.getASTContext(), Base: &Base, IsInheritedVirtualBase: false, Parent: &Entity);
5529	if (EntityIndexToProcess < Args.size()) {
5530	// C++ [dcl.init]p16.6.2.2.
5531	// ...the object is initialized is follows. Let e1, ..., en be the
5532	// elements of the aggregate([dcl.init.aggr]). Let x1, ..., xk be
5533	// the elements of the expression-list...The element ei is
5534	// copy-initialized with xi for 1 <= i <= k.
5535	Expr *E = Args[EntityIndexToProcess];
5536	InitializationKind SubKind = InitializationKind::CreateForInit(
5537	Loc: E->getExprLoc(), /*isDirectInit=*/DirectInit: false, Init: E);
5538	if (!HandleInitializedEntity(SubEntity, SubKind, E))
5539	return;
5540	} else {
5541	// We've processed all of the args, but there are still base classes
5542	// that have to be initialized.
5543	// C++ [dcl.init]p17.6.2.2
5544	// The remaining elements...otherwise are value initialzed
5545	InitializationKind SubKind = InitializationKind::CreateValue(
5546	InitLoc: Kind.getLocation(), LParenLoc: Kind.getLocation(), RParenLoc: Kind.getLocation(),
5547	/*IsImplicit=*/isImplicit: true);
5548	if (!HandleInitializedEntity(SubEntity, SubKind, nullptr))
5549	return;
5550	}
5551	EntityIndexToProcess++;
5552	}
5553	}
5554
5555	for (FieldDecl *FD : RD->fields()) {
5556	// Unnamed bitfields should not be initialized at all, either with an arg
5557	// or by default.
5558	if (FD->isUnnamedBitfield())
5559	continue;
5560
5561	InitializedEntity SubEntity =
5562	InitializedEntity::InitializeMemberFromParenAggInit(FD);
5563
5564	if (EntityIndexToProcess < Args.size()) {
5565	// ...The element ei is copy-initialized with xi for 1 <= i <= k.
5566	Expr *E = Args[EntityIndexToProcess];
5567
5568	// Incomplete array types indicate flexible array members. Do not allow
5569	// paren list initializations of structs with these members, as GCC
5570	// doesn't either.
5571	if (FD->getType()->isIncompleteArrayType()) {
5572	if (!VerifyOnly) {
5573	S.Diag(E->getBeginLoc(), diag::err_flexible_array_init)
5574	<< SourceRange(E->getBeginLoc(), E->getEndLoc());
5575	S.Diag(FD->getLocation(), diag::note_flexible_array_member) << FD;
5576	}
5577	Sequence.SetFailed(
5578	InitializationSequence::FK_ParenthesizedListInitFailed);
5579	return;
5580	}
5581
5582	InitializationKind SubKind = InitializationKind::CreateForInit(
5583	E->getExprLoc(), /*isDirectInit=*/false, E);
5584	if (!HandleInitializedEntity(SubEntity, SubKind, E))
5585	return;
5586
5587	// Unions should have only one initializer expression, so we bail out
5588	// after processing the first field. If there are more initializers then
5589	// it will be caught when we later check whether EntityIndexToProcess is
5590	// less than Args.size();
5591	if (IsUnion) {
5592	InitializedFieldInUnion = FD;
5593	EntityIndexToProcess = 1;
5594	break;
5595	}
5596	} else {
5597	// We've processed all of the args, but there are still members that
5598	// have to be initialized.
5599	if (FD->hasInClassInitializer()) {
5600	if (!VerifyOnly) {
5601	// C++ [dcl.init]p16.6.2.2
5602	// The remaining elements are initialized with their default
5603	// member initializers, if any
5604	ExprResult DIE = S.BuildCXXDefaultInitExpr(
5605	Kind.getParenOrBraceRange().getEnd(), FD);
5606	if (DIE.isInvalid())
5607	return;
5608	S.checkInitializerLifetime(SubEntity, DIE.get());
5609	InitExprs.push_back(DIE.get());
5610	}
5611	} else {
5612	// C++ [dcl.init]p17.6.2.2
5613	// The remaining elements...otherwise are value initialzed
5614	if (FD->getType()->isReferenceType()) {
5615	Sequence.SetFailed(
5616	InitializationSequence::FK_ParenthesizedListInitFailed);
5617	if (!VerifyOnly) {
5618	SourceRange SR = Kind.getParenOrBraceRange();
5619	S.Diag(SR.getEnd(), diag::err_init_reference_member_uninitialized)
5620	<< FD->getType() << SR;
5621	S.Diag(FD->getLocation(), diag::note_uninit_reference_member);
5622	}
5623	return;
5624	}
5625	InitializationKind SubKind = InitializationKind::CreateValue(
5626	Kind.getLocation(), Kind.getLocation(), Kind.getLocation(), true);
5627	if (!HandleInitializedEntity(SubEntity, SubKind, nullptr))
5628	return;
5629	}
5630	}
5631	EntityIndexToProcess++;
5632	}
5633	ResultType = Entity.getType();
5634	}
5635
5636	// Not all of the args have been processed, so there must've been more args
5637	// than were required to initialize the element.
5638	if (EntityIndexToProcess < Args.size()) {
5639	Sequence.SetFailed(InitializationSequence::FK_ParenthesizedListInitFailed);
5640	if (!VerifyOnly) {
5641	QualType T = Entity.getType();
5642	int InitKind = T->isArrayType() ? 0 : T->isUnionType() ? 3 : 4;
5643	SourceRange ExcessInitSR(Args[EntityIndexToProcess]->getBeginLoc(),
5644	Args.back()->getEndLoc());
5645	S.Diag(Kind.getLocation(), diag::err_excess_initializers)
5646	<< InitKind << ExcessInitSR;
5647	}
5648	return;
5649	}
5650
5651	if (VerifyOnly) {
5652	Sequence.setSequenceKind(InitializationSequence::NormalSequence);
5653	Sequence.AddParenthesizedListInitStep(T: Entity.getType());
5654	} else if (Result) {
5655	SourceRange SR = Kind.getParenOrBraceRange();
5656	auto *CPLIE = CXXParenListInitExpr::Create(
5657	C&: S.getASTContext(), Args: InitExprs, T: ResultType, NumUserSpecifiedExprs: Args.size(),
5658	InitLoc: Kind.getLocation(), LParenLoc: SR.getBegin(), RParenLoc: SR.getEnd());
5659	if (ArrayFiller)
5660	CPLIE->setArrayFiller(ArrayFiller);
5661	if (InitializedFieldInUnion)
5662	CPLIE->setInitializedFieldInUnion(InitializedFieldInUnion);
5663	*Result = CPLIE;
5664	S.Diag(Kind.getLocation(),
5665	diag::warn_cxx17_compat_aggregate_init_paren_list)
5666	<< Kind.getLocation() << SR << ResultType;
5667	}
5668	}
5669
5670	/// Attempt a user-defined conversion between two types (C++ [dcl.init]),
5671	/// which enumerates all conversion functions and performs overload resolution
5672	/// to select the best.
5673	static void TryUserDefinedConversion(Sema &S,
5674	QualType DestType,
5675	const InitializationKind &Kind,
5676	Expr *Initializer,
5677	InitializationSequence &Sequence,
5678	bool TopLevelOfInitList) {
5679	assert(!DestType->isReferenceType() && "References are handled elsewhere");
5680	QualType SourceType = Initializer->getType();
5681	assert((DestType->isRecordType() || SourceType->isRecordType()) &&
5682	"Must have a class type to perform a user-defined conversion");
5683
5684	// Build the candidate set directly in the initialization sequence
5685	// structure, so that it will persist if we fail.
5686	OverloadCandidateSet &CandidateSet = Sequence.getFailedCandidateSet();
5687	CandidateSet.clear(CSK: OverloadCandidateSet::CSK_InitByUserDefinedConversion);
5688	CandidateSet.setDestAS(DestType.getQualifiers().getAddressSpace());
5689
5690	// Determine whether we are allowed to call explicit constructors or
5691	// explicit conversion operators.
5692	bool AllowExplicit = Kind.AllowExplicit();
5693
5694	if (const RecordType *DestRecordType = DestType->getAs<RecordType>()) {
5695	// The type we're converting to is a class type. Enumerate its constructors
5696	// to see if there is a suitable conversion.
5697	CXXRecordDecl *DestRecordDecl
5698	= cast<CXXRecordDecl>(Val: DestRecordType->getDecl());
5699
5700	// Try to complete the type we're converting to.
5701	if (S.isCompleteType(Loc: Kind.getLocation(), T: DestType)) {
5702	for (NamedDecl *D : S.LookupConstructors(Class: DestRecordDecl)) {
5703	auto Info = getConstructorInfo(ND: D);
5704	if (!Info.Constructor)
5705	continue;
5706
5707	if (!Info.Constructor->isInvalidDecl() &&
5708	Info.Constructor->isConvertingConstructor(/*AllowExplicit*/true)) {
5709	if (Info.ConstructorTmpl)
5710	S.AddTemplateOverloadCandidate(
5711	FunctionTemplate: Info.ConstructorTmpl, FoundDecl: Info.FoundDecl,
5712	/*ExplicitArgs*/ ExplicitTemplateArgs: nullptr, Args: Initializer, CandidateSet,
5713	/*SuppressUserConversions=*/true,
5714	/*PartialOverloading*/ false, AllowExplicit);
5715	else
5716	S.AddOverloadCandidate(Info.Constructor, Info.FoundDecl,
5717	Initializer, CandidateSet,
5718	/*SuppressUserConversions=*/true,
5719	/*PartialOverloading*/ false, AllowExplicit);
5720	}
5721	}
5722	}
5723	}
5724
5725	SourceLocation DeclLoc = Initializer->getBeginLoc();
5726
5727	if (const RecordType *SourceRecordType = SourceType->getAs<RecordType>()) {
5728	// The type we're converting from is a class type, enumerate its conversion
5729	// functions.
5730
5731	// We can only enumerate the conversion functions for a complete type; if
5732	// the type isn't complete, simply skip this step.
5733	if (S.isCompleteType(Loc: DeclLoc, T: SourceType)) {
5734	CXXRecordDecl *SourceRecordDecl
5735	= cast<CXXRecordDecl>(Val: SourceRecordType->getDecl());
5736
5737	const auto &Conversions =
5738	SourceRecordDecl->getVisibleConversionFunctions();
5739	for (auto I = Conversions.begin(), E = Conversions.end(); I != E; ++I) {
5740	NamedDecl *D = *I;
5741	CXXRecordDecl *ActingDC = cast<CXXRecordDecl>(D->getDeclContext());
5742	if (isa<UsingShadowDecl>(Val: D))
5743	D = cast<UsingShadowDecl>(Val: D)->getTargetDecl();
5744
5745	FunctionTemplateDecl *ConvTemplate = dyn_cast<FunctionTemplateDecl>(Val: D);
5746	CXXConversionDecl *Conv;
5747	if (ConvTemplate)
5748	Conv = cast<CXXConversionDecl>(Val: ConvTemplate->getTemplatedDecl());
5749	else
5750	Conv = cast<CXXConversionDecl>(Val: D);
5751
5752	if (ConvTemplate)
5753	S.AddTemplateConversionCandidate(
5754	FunctionTemplate: ConvTemplate, FoundDecl: I.getPair(), ActingContext: ActingDC, From: Initializer, ToType: DestType,
5755	CandidateSet, AllowObjCConversionOnExplicit: AllowExplicit, AllowExplicit);
5756	else
5757	S.AddConversionCandidate(Conversion: Conv, FoundDecl: I.getPair(), ActingContext: ActingDC, From: Initializer,
5758	ToType: DestType, CandidateSet, AllowObjCConversionOnExplicit: AllowExplicit,
5759	AllowExplicit);
5760	}
5761	}
5762	}
5763
5764	// Perform overload resolution. If it fails, return the failed result.
5765	OverloadCandidateSet::iterator Best;
5766	if (OverloadingResult Result
5767	= CandidateSet.BestViableFunction(S, Loc: DeclLoc, Best)) {
5768	Sequence.SetOverloadFailure(
5769	Failure: InitializationSequence::FK_UserConversionOverloadFailed, Result);
5770
5771	// [class.copy.elision]p3:
5772	// In some copy-initialization contexts, a two-stage overload resolution
5773	// is performed.
5774	// If the first overload resolution selects a deleted function, we also
5775	// need the initialization sequence to decide whether to perform the second
5776	// overload resolution.
5777	if (!(Result == OR_Deleted &&
5778	Kind.getKind() == InitializationKind::IK_Copy))
5779	return;
5780	}
5781
5782	FunctionDecl *Function = Best->Function;
5783	Function->setReferenced();
5784	bool HadMultipleCandidates = (CandidateSet.size() > 1);
5785
5786	if (isa<CXXConstructorDecl>(Val: Function)) {
5787	// Add the user-defined conversion step. Any cv-qualification conversion is
5788	// subsumed by the initialization. Per DR5, the created temporary is of the
5789	// cv-unqualified type of the destination.
5790	Sequence.AddUserConversionStep(Function, FoundDecl: Best->FoundDecl,
5791	T: DestType.getUnqualifiedType(),
5792	HadMultipleCandidates);
5793
5794	// C++14 and before:
5795	// - if the function is a constructor, the call initializes a temporary
5796	// of the cv-unqualified version of the destination type. The [...]
5797	// temporary [...] is then used to direct-initialize, according to the
5798	// rules above, the object that is the destination of the
5799	// copy-initialization.
5800	// Note that this just performs a simple object copy from the temporary.
5801	//
5802	// C++17:
5803	// - if the function is a constructor, the call is a prvalue of the
5804	// cv-unqualified version of the destination type whose return object
5805	// is initialized by the constructor. The call is used to
5806	// direct-initialize, according to the rules above, the object that
5807	// is the destination of the copy-initialization.
5808	// Therefore we need to do nothing further.
5809	//
5810	// FIXME: Mark this copy as extraneous.
5811	if (!S.getLangOpts().CPlusPlus17)
5812	Sequence.AddFinalCopy(T: DestType);
5813	else if (DestType.hasQualifiers())
5814	Sequence.AddQualificationConversionStep(Ty: DestType, VK: VK_PRValue);
5815	return;
5816	}
5817
5818	// Add the user-defined conversion step that calls the conversion function.
5819	QualType ConvType = Function->getCallResultType();
5820	Sequence.AddUserConversionStep(Function, FoundDecl: Best->FoundDecl, T: ConvType,
5821	HadMultipleCandidates);
5822
5823	if (ConvType->getAs<RecordType>()) {
5824	// The call is used to direct-initialize [...] the object that is the
5825	// destination of the copy-initialization.
5826	//
5827	// In C++17, this does not call a constructor if we enter /17.6.1:
5828	// - If the initializer expression is a prvalue and the cv-unqualified
5829	// version of the source type is the same as the class of the
5830	// destination [... do not make an extra copy]
5831	//
5832	// FIXME: Mark this copy as extraneous.
5833	if (!S.getLangOpts().CPlusPlus17 ||
5834	Function->getReturnType()->isReferenceType() ||
5835	!S.Context.hasSameUnqualifiedType(T1: ConvType, T2: DestType))
5836	Sequence.AddFinalCopy(T: DestType);
5837	else if (!S.Context.hasSameType(T1: ConvType, T2: DestType))
5838	Sequence.AddQualificationConversionStep(Ty: DestType, VK: VK_PRValue);
5839	return;
5840	}
5841
5842	// If the conversion following the call to the conversion function
5843	// is interesting, add it as a separate step.
5844	if (Best->FinalConversion.First || Best->FinalConversion.Second ||
5845	Best->FinalConversion.Third) {
5846	ImplicitConversionSequence ICS;
5847	ICS.setStandard();
5848	ICS.Standard = Best->FinalConversion;
5849	Sequence.AddConversionSequenceStep(ICS, T: DestType, TopLevelOfInitList);
5850	}
5851	}
5852
5853	/// An egregious hack for compatibility with libstdc++-4.2: in <tr1/hashtable>,
5854	/// a function with a pointer return type contains a 'return false;' statement.
5855	/// In C++11, 'false' is not a null pointer, so this breaks the build of any
5856	/// code using that header.
5857	///
5858	/// Work around this by treating 'return false;' as zero-initializing the result
5859	/// if it's used in a pointer-returning function in a system header.
5860	static bool isLibstdcxxPointerReturnFalseHack(Sema &S,
5861	const InitializedEntity &Entity,
5862	const Expr *Init) {
5863	return S.getLangOpts().CPlusPlus11 &&
5864	Entity.getKind() == InitializedEntity::EK_Result &&
5865	Entity.getType()->isPointerType() &&
5866	isa<CXXBoolLiteralExpr>(Val: Init) &&
5867	!cast<CXXBoolLiteralExpr>(Val: Init)->getValue() &&
5868	S.getSourceManager().isInSystemHeader(Loc: Init->getExprLoc());
5869	}
5870
5871	/// The non-zero enum values here are indexes into diagnostic alternatives.
5872	enum InvalidICRKind { IIK_okay, IIK_nonlocal, IIK_nonscalar };
5873
5874	/// Determines whether this expression is an acceptable ICR source.
5875	static InvalidICRKind isInvalidICRSource(ASTContext &C, Expr *e,
5876	bool isAddressOf, bool &isWeakAccess) {
5877	// Skip parens.
5878	e = e->IgnoreParens();
5879
5880	// Skip address-of nodes.
5881	if (UnaryOperator *op = dyn_cast<UnaryOperator>(Val: e)) {
5882	if (op->getOpcode() == UO_AddrOf)
5883	return isInvalidICRSource(C, e: op->getSubExpr(), /*addressof*/ isAddressOf: true,
5884	isWeakAccess);
5885
5886	// Skip certain casts.
5887	} else if (CastExpr *ce = dyn_cast<CastExpr>(Val: e)) {
5888	switch (ce->getCastKind()) {
5889	case CK_Dependent:
5890	case CK_BitCast:
5891	case CK_LValueBitCast:
5892	case CK_NoOp:
5893	return isInvalidICRSource(C, e: ce->getSubExpr(), isAddressOf, isWeakAccess);
5894
5895	case CK_ArrayToPointerDecay:
5896	return IIK_nonscalar;
5897
5898	case CK_NullToPointer:
5899	return IIK_okay;
5900
5901	default:
5902	break;
5903	}
5904
5905	// If we have a declaration reference, it had better be a local variable.
5906	} else if (isa<DeclRefExpr>(Val: e)) {
5907	// set isWeakAccess to true, to mean that there will be an implicit
5908	// load which requires a cleanup.
5909	if (e->getType().getObjCLifetime() == Qualifiers::OCL_Weak)
5910	isWeakAccess = true;
5911
5912	if (!isAddressOf) return IIK_nonlocal;
5913
5914	VarDecl *var = dyn_cast<VarDecl>(Val: cast<DeclRefExpr>(Val: e)->getDecl());
5915	if (!var) return IIK_nonlocal;
5916
5917	return (var->hasLocalStorage() ? IIK_okay : IIK_nonlocal);
5918
5919	// If we have a conditional operator, check both sides.
5920	} else if (ConditionalOperator *cond = dyn_cast<ConditionalOperator>(Val: e)) {
5921	if (InvalidICRKind iik = isInvalidICRSource(C, e: cond->getLHS(), isAddressOf,
5922	isWeakAccess))
5923	return iik;
5924
5925	return isInvalidICRSource(C, e: cond->getRHS(), isAddressOf, isWeakAccess);
5926
5927	// These are never scalar.
5928	} else if (isa<ArraySubscriptExpr>(Val: e)) {
5929	return IIK_nonscalar;
5930
5931	// Otherwise, it needs to be a null pointer constant.
5932	} else {
5933	return (e->isNullPointerConstant(Ctx&: C, NPC: Expr::NPC_ValueDependentIsNull)
5934	? IIK_okay : IIK_nonlocal);
5935	}
5936
5937	return IIK_nonlocal;
5938	}
5939
5940	/// Check whether the given expression is a valid operand for an
5941	/// indirect copy/restore.
5942	static void checkIndirectCopyRestoreSource(Sema &S, Expr *src) {
5943	assert(src->isPRValue());
5944	bool isWeakAccess = false;
5945	InvalidICRKind iik = isInvalidICRSource(C&: S.Context, e: src, isAddressOf: false, isWeakAccess);
5946	// If isWeakAccess to true, there will be an implicit
5947	// load which requires a cleanup.
5948	if (S.getLangOpts().ObjCAutoRefCount && isWeakAccess)
5949	S.Cleanup.setExprNeedsCleanups(true);
5950
5951	if (iik == IIK_okay) return;
5952
5953	S.Diag(src->getExprLoc(), diag::err_arc_nonlocal_writeback)
5954	<< ((unsigned) iik - 1) // shift index into diagnostic explanations
5955	<< src->getSourceRange();
5956	}
5957
5958	/// Determine whether we have compatible array types for the
5959	/// purposes of GNU by-copy array initialization.
5960	static bool hasCompatibleArrayTypes(ASTContext &Context, const ArrayType *Dest,
5961	const ArrayType *Source) {
5962	// If the source and destination array types are equivalent, we're
5963	// done.
5964	if (Context.hasSameType(T1: QualType(Dest, 0), T2: QualType(Source, 0)))
5965	return true;
5966
5967	// Make sure that the element types are the same.
5968	if (!Context.hasSameType(T1: Dest->getElementType(), T2: Source->getElementType()))
5969	return false;
5970
5971	// The only mismatch we allow is when the destination is an
5972	// incomplete array type and the source is a constant array type.
5973	return Source->isConstantArrayType() && Dest->isIncompleteArrayType();
5974	}
5975
5976	static bool tryObjCWritebackConversion(Sema &S,
5977	InitializationSequence &Sequence,
5978	const InitializedEntity &Entity,
5979	Expr *Initializer) {
5980	bool ArrayDecay = false;
5981	QualType ArgType = Initializer->getType();
5982	QualType ArgPointee;
5983	if (const ArrayType *ArgArrayType = S.Context.getAsArrayType(T: ArgType)) {
5984	ArrayDecay = true;
5985	ArgPointee = ArgArrayType->getElementType();
5986	ArgType = S.Context.getPointerType(T: ArgPointee);
5987	}
5988
5989	// Handle write-back conversion.
5990	QualType ConvertedArgType;
5991	if (!S.isObjCWritebackConversion(FromType: ArgType, ToType: Entity.getType(),
5992	ConvertedType&: ConvertedArgType))
5993	return false;
5994
5995	// We should copy unless we're passing to an argument explicitly
5996	// marked 'out'.
5997	bool ShouldCopy = true;
5998	if (ParmVarDecl *param = cast_or_null<ParmVarDecl>(Val: Entity.getDecl()))
5999	ShouldCopy = (param->getObjCDeclQualifier() != ParmVarDecl::OBJC_TQ_Out);
6000
6001	// Do we need an lvalue conversion?
6002	if (ArrayDecay || Initializer->isGLValue()) {
6003	ImplicitConversionSequence ICS;
6004	ICS.setStandard();
6005	ICS.Standard.setAsIdentityConversion();
6006
6007	QualType ResultType;
6008	if (ArrayDecay) {
6009	ICS.Standard.First = ICK_Array_To_Pointer;
6010	ResultType = S.Context.getPointerType(T: ArgPointee);
6011	} else {
6012	ICS.Standard.First = ICK_Lvalue_To_Rvalue;
6013	ResultType = Initializer->getType().getNonLValueExprType(Context: S.Context);
6014	}
6015
6016	Sequence.AddConversionSequenceStep(ICS, T: ResultType);
6017	}
6018
6019	Sequence.AddPassByIndirectCopyRestoreStep(type: Entity.getType(), shouldCopy: ShouldCopy);
6020	return true;
6021	}
6022
6023	static bool TryOCLSamplerInitialization(Sema &S,
6024	InitializationSequence &Sequence,
6025	QualType DestType,
6026	Expr *Initializer) {
6027	if (!S.getLangOpts().OpenCL || !DestType->isSamplerT() ||
6028	(!Initializer->isIntegerConstantExpr(Ctx: S.Context) &&
6029	!Initializer->getType()->isSamplerT()))
6030	return false;
6031
6032	Sequence.AddOCLSamplerInitStep(T: DestType);
6033	return true;
6034	}
6035
6036	static bool IsZeroInitializer(Expr *Initializer, Sema &S) {
6037	return Initializer->isIntegerConstantExpr(Ctx: S.getASTContext()) &&
6038	(Initializer->EvaluateKnownConstInt(Ctx: S.getASTContext()) == 0);
6039	}
6040
6041	static bool TryOCLZeroOpaqueTypeInitialization(Sema &S,
6042	InitializationSequence &Sequence,
6043	QualType DestType,
6044	Expr *Initializer) {
6045	if (!S.getLangOpts().OpenCL)
6046	return false;
6047
6048	//
6049	// OpenCL 1.2 spec, s6.12.10
6050	//
6051	// The event argument can also be used to associate the
6052	// async_work_group_copy with a previous async copy allowing
6053	// an event to be shared by multiple async copies; otherwise
6054	// event should be zero.
6055	//
6056	if (DestType->isEventT() || DestType->isQueueT()) {
6057	if (!IsZeroInitializer(Initializer, S))
6058	return false;
6059
6060	Sequence.AddOCLZeroOpaqueTypeStep(T: DestType);
6061	return true;
6062	}
6063
6064	// We should allow zero initialization for all types defined in the
6065	// cl_intel_device_side_avc_motion_estimation extension, except
6066	// intel_sub_group_avc_mce_payload_t and intel_sub_group_avc_mce_result_t.
6067	if (S.getOpenCLOptions().isAvailableOption(
6068	Ext: "cl_intel_device_side_avc_motion_estimation", LO: S.getLangOpts()) &&
6069	DestType->isOCLIntelSubgroupAVCType()) {
6070	if (DestType->isOCLIntelSubgroupAVCMcePayloadType() ||
6071	DestType->isOCLIntelSubgroupAVCMceResultType())
6072	return false;
6073	if (!IsZeroInitializer(Initializer, S))
6074	return false;
6075
6076	Sequence.AddOCLZeroOpaqueTypeStep(T: DestType);
6077	return true;
6078	}
6079
6080	return false;
6081	}
6082
6083	InitializationSequence::InitializationSequence(
6084	Sema &S, const InitializedEntity &Entity, const InitializationKind &Kind,
6085	MultiExprArg Args, bool TopLevelOfInitList, bool TreatUnavailableAsInvalid)
6086	: FailedOverloadResult(OR_Success),
6087	FailedCandidateSet(Kind.getLocation(), OverloadCandidateSet::CSK_Normal) {
6088	InitializeFrom(S, Entity, Kind, Args, TopLevelOfInitList,
6089	TreatUnavailableAsInvalid);
6090	}
6091
6092	/// Tries to get a FunctionDecl out of `E`. If it succeeds and we can take the
6093	/// address of that function, this returns true. Otherwise, it returns false.
6094	static bool isExprAnUnaddressableFunction(Sema &S, const Expr *E) {
6095	auto *DRE = dyn_cast<DeclRefExpr>(Val: E);
6096	if (!DRE || !isa<FunctionDecl>(Val: DRE->getDecl()))
6097	return false;
6098
6099	return !S.checkAddressOfFunctionIsAvailable(
6100	Function: cast<FunctionDecl>(Val: DRE->getDecl()));
6101	}
6102
6103	/// Determine whether we can perform an elementwise array copy for this kind
6104	/// of entity.
6105	static bool canPerformArrayCopy(const InitializedEntity &Entity) {
6106	switch (Entity.getKind()) {
6107	case InitializedEntity::EK_LambdaCapture:
6108	// C++ [expr.prim.lambda]p24:
6109	// For array members, the array elements are direct-initialized in
6110	// increasing subscript order.
6111	return true;
6112
6113	case InitializedEntity::EK_Variable:
6114	// C++ [dcl.decomp]p1:
6115	// [...] each element is copy-initialized or direct-initialized from the
6116	// corresponding element of the assignment-expression [...]
6117	return isa<DecompositionDecl>(Val: Entity.getDecl());
6118
6119	case InitializedEntity::EK_Member:
6120	// C++ [class.copy.ctor]p14:
6121	// - if the member is an array, each element is direct-initialized with
6122	// the corresponding subobject of x
6123	return Entity.isImplicitMemberInitializer();
6124
6125	case InitializedEntity::EK_ArrayElement:
6126	// All the above cases are intended to apply recursively, even though none
6127	// of them actually say that.
6128	if (auto *E = Entity.getParent())
6129	return canPerformArrayCopy(Entity: *E);
6130	break;
6131
6132	default:
6133	break;
6134	}
6135
6136	return false;
6137	}
6138
6139	void InitializationSequence::InitializeFrom(Sema &S,
6140	const InitializedEntity &Entity,
6141	const InitializationKind &Kind,
6142	MultiExprArg Args,
6143	bool TopLevelOfInitList,
6144	bool TreatUnavailableAsInvalid) {
6145	ASTContext &Context = S.Context;
6146
6147	// Eliminate non-overload placeholder types in the arguments. We
6148	// need to do this before checking whether types are dependent
6149	// because lowering a pseudo-object expression might well give us
6150	// something of dependent type.
6151	for (unsigned I = 0, E = Args.size(); I != E; ++I)
6152	if (Args[I]->getType()->isNonOverloadPlaceholderType()) {
6153	// FIXME: should we be doing this here?
6154	ExprResult result = S.CheckPlaceholderExpr(E: Args[I]);
6155	if (result.isInvalid()) {
6156	SetFailed(FK_PlaceholderType);
6157	return;
6158	}
6159	Args[I] = result.get();
6160	}
6161
6162	// C++0x [dcl.init]p16:
6163	// The semantics of initializers are as follows. The destination type is
6164	// the type of the object or reference being initialized and the source
6165	// type is the type of the initializer expression. The source type is not
6166	// defined when the initializer is a braced-init-list or when it is a
6167	// parenthesized list of expressions.
6168	QualType DestType = Entity.getType();
6169
6170	if (DestType->isDependentType() ||
6171	Expr::hasAnyTypeDependentArguments(Exprs: Args)) {
6172	SequenceKind = DependentSequence;
6173	return;
6174	}
6175
6176	// Almost everything is a normal sequence.
6177	setSequenceKind(NormalSequence);
6178
6179	QualType SourceType;
6180	Expr *Initializer = nullptr;
6181	if (Args.size() == 1) {
6182	Initializer = Args[0];
6183	if (S.getLangOpts().ObjC) {
6184	if (S.CheckObjCBridgeRelatedConversions(Loc: Initializer->getBeginLoc(),
6185	DestType, SrcType: Initializer->getType(),
6186	SrcExpr&: Initializer) ||
6187	S.CheckConversionToObjCLiteral(DstType: DestType, SrcExpr&: Initializer))
6188	Args[0] = Initializer;
6189	}
6190	if (!isa<InitListExpr>(Val: Initializer))
6191	SourceType = Initializer->getType();
6192	}
6193
6194	// - If the initializer is a (non-parenthesized) braced-init-list, the
6195	// object is list-initialized (8.5.4).
6196	if (Kind.getKind() != InitializationKind::IK_Direct) {
6197	if (InitListExpr *InitList = dyn_cast_or_null<InitListExpr>(Val: Initializer)) {
6198	TryListInitialization(S, Entity, Kind, InitList, Sequence&: *this,
6199	TreatUnavailableAsInvalid);
6200	return;
6201	}
6202	}
6203
6204	// - If the destination type is a reference type, see 8.5.3.
6205	if (DestType->isReferenceType()) {
6206	// C++0x [dcl.init.ref]p1:
6207	// A variable declared to be a T& or T&&, that is, "reference to type T"
6208	// (8.3.2), shall be initialized by an object, or function, of type T or
6209	// by an object that can be converted into a T.
6210	// (Therefore, multiple arguments are not permitted.)
6211	if (Args.size() != 1)
6212	SetFailed(FK_TooManyInitsForReference);
6213	// C++17 [dcl.init.ref]p5:
6214	// A reference [...] is initialized by an expression [...] as follows:
6215	// If the initializer is not an expression, presumably we should reject,
6216	// but the standard fails to actually say so.
6217	else if (isa<InitListExpr>(Val: Args[0]))
6218	SetFailed(FK_ParenthesizedListInitForReference);
6219	else
6220	TryReferenceInitialization(S, Entity, Kind, Initializer: Args[0], Sequence&: *this,
6221	TopLevelOfInitList);
6222	return;
6223	}
6224
6225	// - If the initializer is (), the object is value-initialized.
6226	if (Kind.getKind() == InitializationKind::IK_Value ||
6227	(Kind.getKind() == InitializationKind::IK_Direct && Args.empty())) {
6228	TryValueInitialization(S, Entity, Kind, Sequence&: *this);
6229	return;
6230	}
6231
6232	// Handle default initialization.
6233	if (Kind.getKind() == InitializationKind::IK_Default) {
6234	TryDefaultInitialization(S, Entity, Kind, Sequence&: *this);
6235	return;
6236	}
6237
6238	// - If the destination type is an array of characters, an array of
6239	// char16_t, an array of char32_t, or an array of wchar_t, and the
6240	// initializer is a string literal, see 8.5.2.
6241	// - Otherwise, if the destination type is an array, the program is
6242	// ill-formed.
6243	if (const ArrayType *DestAT = Context.getAsArrayType(T: DestType)) {
6244	if (Initializer && isa<VariableArrayType>(Val: DestAT)) {
6245	SetFailed(FK_VariableLengthArrayHasInitializer);
6246	return;
6247	}
6248
6249	if (Initializer) {
6250	switch (IsStringInit(Init: Initializer, AT: DestAT, Context)) {
6251	case SIF_None:
6252	TryStringLiteralInitialization(S, Entity, Kind, Initializer, Sequence&: *this);
6253	return;
6254	case SIF_NarrowStringIntoWideChar:
6255	SetFailed(FK_NarrowStringIntoWideCharArray);
6256	return;
6257	case SIF_WideStringIntoChar:
6258	SetFailed(FK_WideStringIntoCharArray);
6259	return;
6260	case SIF_IncompatWideStringIntoWideChar:
6261	SetFailed(FK_IncompatWideStringIntoWideChar);
6262	return;
6263	case SIF_PlainStringIntoUTF8Char:
6264	SetFailed(FK_PlainStringIntoUTF8Char);
6265	return;
6266	case SIF_UTF8StringIntoPlainChar:
6267	SetFailed(FK_UTF8StringIntoPlainChar);
6268	return;
6269	case SIF_Other:
6270	break;
6271	}
6272	}
6273
6274	// Some kinds of initialization permit an array to be initialized from
6275	// another array of the same type, and perform elementwise initialization.
6276	if (Initializer && isa<ConstantArrayType>(Val: DestAT) &&
6277	S.Context.hasSameUnqualifiedType(T1: Initializer->getType(),
6278	T2: Entity.getType()) &&
6279	canPerformArrayCopy(Entity)) {
6280	// If source is a prvalue, use it directly.
6281	if (Initializer->isPRValue()) {
6282	AddArrayInitStep(T: DestType, /*IsGNUExtension*/false);
6283	return;
6284	}
6285
6286	// Emit element-at-a-time copy loop.
6287	InitializedEntity Element =
6288	InitializedEntity::InitializeElement(Context&: S.Context, Index: 0, Parent: Entity);
6289	QualType InitEltT =
6290	Context.getAsArrayType(T: Initializer->getType())->getElementType();
6291	OpaqueValueExpr OVE(Initializer->getExprLoc(), InitEltT,
6292	Initializer->getValueKind(),
6293	Initializer->getObjectKind());
6294	Expr *OVEAsExpr = &OVE;
6295	InitializeFrom(S, Entity: Element, Kind, Args: OVEAsExpr, TopLevelOfInitList,
6296	TreatUnavailableAsInvalid);
6297	if (!Failed())
6298	AddArrayInitLoopStep(T: Entity.getType(), EltT: InitEltT);
6299	return;
6300	}
6301
6302	// Note: as an GNU C extension, we allow initialization of an
6303	// array from a compound literal that creates an array of the same
6304	// type, so long as the initializer has no side effects.
6305	if (!S.getLangOpts().CPlusPlus && Initializer &&
6306	isa<CompoundLiteralExpr>(Val: Initializer->IgnoreParens()) &&
6307	Initializer->getType()->isArrayType()) {
6308	const ArrayType *SourceAT
6309	= Context.getAsArrayType(T: Initializer->getType());
6310	if (!hasCompatibleArrayTypes(Context&: S.Context, Dest: DestAT, Source: SourceAT))
6311	SetFailed(FK_ArrayTypeMismatch);
6312	else if (Initializer->HasSideEffects(Ctx: S.Context))
6313	SetFailed(FK_NonConstantArrayInit);
6314	else {
6315	AddArrayInitStep(T: DestType, /*IsGNUExtension*/true);
6316	}
6317	}
6318	// Note: as a GNU C++ extension, we allow list-initialization of a
6319	// class member of array type from a parenthesized initializer list.
6320	else if (S.getLangOpts().CPlusPlus &&
6321	Entity.getKind() == InitializedEntity::EK_Member &&
6322	Initializer && isa<InitListExpr>(Val: Initializer)) {
6323	TryListInitialization(S, Entity, Kind, InitList: cast<InitListExpr>(Val: Initializer),
6324	Sequence&: *this, TreatUnavailableAsInvalid);
6325	AddParenthesizedArrayInitStep(T: DestType);
6326	} else if (S.getLangOpts().CPlusPlus20 && !TopLevelOfInitList &&
6327	Kind.getKind() == InitializationKind::IK_Direct)
6328	TryOrBuildParenListInitialization(S, Entity, Kind, Args, Sequence&: *this,
6329	/*VerifyOnly=*/true);
6330	else if (DestAT->getElementType()->isCharType())
6331	SetFailed(FK_ArrayNeedsInitListOrStringLiteral);
6332	else if (IsWideCharCompatible(T: DestAT->getElementType(), Context))
6333	SetFailed(FK_ArrayNeedsInitListOrWideStringLiteral);
6334	else
6335	SetFailed(FK_ArrayNeedsInitList);
6336
6337	return;
6338	}
6339
6340	// Determine whether we should consider writeback conversions for
6341	// Objective-C ARC.
6342	bool allowObjCWritebackConversion = S.getLangOpts().ObjCAutoRefCount &&
6343	Entity.isParameterKind();
6344
6345	if (TryOCLSamplerInitialization(S, Sequence&: *this, DestType, Initializer))
6346	return;
6347
6348	// We're at the end of the line for C: it's either a write-back conversion
6349	// or it's a C assignment. There's no need to check anything else.
6350	if (!S.getLangOpts().CPlusPlus) {
6351	assert(Initializer && "Initializer must be non-null");
6352	// If allowed, check whether this is an Objective-C writeback conversion.
6353	if (allowObjCWritebackConversion &&
6354	tryObjCWritebackConversion(S, Sequence&: *this, Entity, Initializer)) {
6355	return;
6356	}
6357
6358	if (TryOCLZeroOpaqueTypeInitialization(S, Sequence&: *this, DestType, Initializer))
6359	return;
6360
6361	// Handle initialization in C
6362	AddCAssignmentStep(T: DestType);
6363	MaybeProduceObjCObject(S, Sequence&: *this, Entity);
6364	return;
6365	}
6366
6367	assert(S.getLangOpts().CPlusPlus);
6368
6369	// - If the destination type is a (possibly cv-qualified) class type:
6370	if (DestType->isRecordType()) {
6371	// - If the initialization is direct-initialization, or if it is
6372	// copy-initialization where the cv-unqualified version of the
6373	// source type is the same class as, or a derived class of, the
6374	// class of the destination, constructors are considered. [...]
6375	if (Kind.getKind() == InitializationKind::IK_Direct ||
6376	(Kind.getKind() == InitializationKind::IK_Copy &&
6377	(Context.hasSameUnqualifiedType(T1: SourceType, T2: DestType) ||
6378	(Initializer && S.IsDerivedFrom(Initializer->getBeginLoc(),
6379	SourceType, DestType))))) {
6380	TryConstructorInitialization(S, Entity, Kind, Args, DestType, DestArrayType: DestType,
6381	Sequence&: *this);
6382
6383	// We fall back to the "no matching constructor" path if the
6384	// failed candidate set has functions other than the three default
6385	// constructors. For example, conversion function.
6386	if (const auto *RD =
6387	dyn_cast<CXXRecordDecl>(Val: DestType->getAs<RecordType>()->getDecl());
6388	// In general, we should call isCompleteType for RD to check its
6389	// completeness, we don't call it here as it was already called in the
6390	// above TryConstructorInitialization.
6391	S.getLangOpts().CPlusPlus20 && RD && RD->hasDefinition() &&
6392	RD->isAggregate() && Failed() &&
6393	getFailureKind() == FK_ConstructorOverloadFailed) {
6394	// Do not attempt paren list initialization if overload resolution
6395	// resolves to a deleted function .
6396	//
6397	// We may reach this condition if we have a union wrapping a class with
6398	// a non-trivial copy or move constructor and we call one of those two
6399	// constructors. The union is an aggregate, but the matched constructor
6400	// is implicitly deleted, so we need to prevent aggregate initialization
6401	// (otherwise, it'll attempt aggregate initialization by initializing
6402	// the first element with a reference to the union).
6403	OverloadCandidateSet::iterator Best;
6404	OverloadingResult OR = getFailedCandidateSet().BestViableFunction(
6405	S, Loc: Kind.getLocation(), Best);
6406	if (OR != OverloadingResult::OR_Deleted) {
6407	// C++20 [dcl.init] 17.6.2.2:
6408	// - Otherwise, if no constructor is viable, the destination type is
6409	// an
6410	// aggregate class, and the initializer is a parenthesized
6411	// expression-list.
6412	TryOrBuildParenListInitialization(S, Entity, Kind, Args, Sequence&: *this,
6413	/*VerifyOnly=*/true);
6414	}
6415	}
6416	} else {
6417	// - Otherwise (i.e., for the remaining copy-initialization cases),
6418	// user-defined conversion sequences that can convert from the
6419	// source type to the destination type or (when a conversion
6420	// function is used) to a derived class thereof are enumerated as
6421	// described in 13.3.1.4, and the best one is chosen through
6422	// overload resolution (13.3).
6423	assert(Initializer && "Initializer must be non-null");
6424	TryUserDefinedConversion(S, DestType, Kind, Initializer, Sequence&: *this,
6425	TopLevelOfInitList);
6426	}
6427	return;
6428	}
6429
6430	assert(Args.size() >= 1 && "Zero-argument case handled above");
6431
6432	// For HLSL ext vector types we allow list initialization behavior for C++
6433	// constructor syntax. This is accomplished by converting initialization
6434	// arguments an InitListExpr late.
6435	if (S.getLangOpts().HLSL && DestType->isExtVectorType() &&
6436	(SourceType.isNull() ||
6437	!Context.hasSameUnqualifiedType(T1: SourceType, T2: DestType))) {
6438
6439	llvm::SmallVector<Expr *> InitArgs;
6440	for (auto *Arg : Args) {
6441	if (Arg->getType()->isExtVectorType()) {
6442	const auto *VTy = Arg->getType()->castAs<ExtVectorType>();
6443	unsigned Elm = VTy->getNumElements();
6444	for (unsigned Idx = 0; Idx < Elm; ++Idx) {
6445	InitArgs.emplace_back(Args: new (Context) ArraySubscriptExpr(
6446	Arg,
6447	IntegerLiteral::Create(
6448	Context, llvm::APInt(Context.getIntWidth(T: Context.IntTy), Idx),
6449	Context.IntTy, SourceLocation()),
6450	VTy->getElementType(), Arg->getValueKind(), Arg->getObjectKind(),
6451	SourceLocation()));
6452	}
6453	} else
6454	InitArgs.emplace_back(Args&: Arg);
6455	}
6456	InitListExpr *ILE = new (Context) InitListExpr(
6457	S.getASTContext(), SourceLocation(), InitArgs, SourceLocation());
6458	Args[0] = ILE;
6459	AddListInitializationStep(T: DestType);
6460	return;
6461	}
6462
6463	// The remaining cases all need a source type.
6464	if (Args.size() > 1) {
6465	SetFailed(FK_TooManyInitsForScalar);
6466	return;
6467	} else if (isa<InitListExpr>(Val: Args[0])) {
6468	SetFailed(FK_ParenthesizedListInitForScalar);
6469	return;
6470	}
6471
6472	// - Otherwise, if the source type is a (possibly cv-qualified) class
6473	// type, conversion functions are considered.
6474	if (!SourceType.isNull() && SourceType->isRecordType()) {
6475	assert(Initializer && "Initializer must be non-null");
6476	// For a conversion to _Atomic(T) from either T or a class type derived
6477	// from T, initialize the T object then convert to _Atomic type.
6478	bool NeedAtomicConversion = false;
6479	if (const AtomicType *Atomic = DestType->getAs<AtomicType>()) {
6480	if (Context.hasSameUnqualifiedType(T1: SourceType, T2: Atomic->getValueType()) ||
6481	S.IsDerivedFrom(Initializer->getBeginLoc(), SourceType,
6482	Atomic->getValueType())) {
6483	DestType = Atomic->getValueType();
6484	NeedAtomicConversion = true;
6485	}
6486	}
6487
6488	TryUserDefinedConversion(S, DestType, Kind, Initializer, Sequence&: *this,
6489	TopLevelOfInitList);
6490	MaybeProduceObjCObject(S, Sequence&: *this, Entity);
6491	if (!Failed() && NeedAtomicConversion)
6492	AddAtomicConversionStep(Ty: Entity.getType());
6493	return;
6494	}
6495
6496	// - Otherwise, if the initialization is direct-initialization, the source
6497	// type is std::nullptr_t, and the destination type is bool, the initial
6498	// value of the object being initialized is false.
6499	if (!SourceType.isNull() && SourceType->isNullPtrType() &&
6500	DestType->isBooleanType() &&
6501	Kind.getKind() == InitializationKind::IK_Direct) {
6502	AddConversionSequenceStep(
6503	ICS: ImplicitConversionSequence::getNullptrToBool(SourceType, DestType,
6504	NeedLValToRVal: Initializer->isGLValue()),
6505	T: DestType);
6506	return;
6507	}
6508
6509	// - Otherwise, the initial value of the object being initialized is the
6510	// (possibly converted) value of the initializer expression. Standard
6511	// conversions (Clause 4) will be used, if necessary, to convert the
6512	// initializer expression to the cv-unqualified version of the
6513	// destination type; no user-defined conversions are considered.
6514
6515	ImplicitConversionSequence ICS
6516	= S.TryImplicitConversion(From: Initializer, ToType: DestType,
6517	/*SuppressUserConversions*/true,
6518	AllowExplicit: Sema::AllowedExplicit::None,
6519	/*InOverloadResolution*/ false,
6520	/*CStyle=*/Kind.isCStyleOrFunctionalCast(),
6521	AllowObjCWritebackConversion: allowObjCWritebackConversion);
6522
6523	if (ICS.isStandard() &&
6524	ICS.Standard.Second == ICK_Writeback_Conversion) {
6525	// Objective-C ARC writeback conversion.
6526
6527	// We should copy unless we're passing to an argument explicitly
6528	// marked 'out'.
6529	bool ShouldCopy = true;
6530	if (ParmVarDecl *Param = cast_or_null<ParmVarDecl>(Val: Entity.getDecl()))
6531	ShouldCopy = (Param->getObjCDeclQualifier() != ParmVarDecl::OBJC_TQ_Out);
6532
6533	// If there was an lvalue adjustment, add it as a separate conversion.
6534	if (ICS.Standard.First == ICK_Array_To_Pointer ||
6535	ICS.Standard.First == ICK_Lvalue_To_Rvalue) {
6536	ImplicitConversionSequence LvalueICS;
6537	LvalueICS.setStandard();
6538	LvalueICS.Standard.setAsIdentityConversion();
6539	LvalueICS.Standard.setAllToTypes(ICS.Standard.getToType(Idx: 0));
6540	LvalueICS.Standard.First = ICS.Standard.First;
6541	AddConversionSequenceStep(ICS: LvalueICS, T: ICS.Standard.getToType(Idx: 0));
6542	}
6543
6544	AddPassByIndirectCopyRestoreStep(type: DestType, shouldCopy: ShouldCopy);
6545	} else if (ICS.isBad()) {
6546	DeclAccessPair dap;
6547	if (isLibstdcxxPointerReturnFalseHack(S, Entity, Init: Initializer)) {
6548	AddZeroInitializationStep(T: Entity.getType());
6549	} else if (Initializer->getType() == Context.OverloadTy &&
6550	!S.ResolveAddressOfOverloadedFunction(AddressOfExpr: Initializer, TargetType: DestType,
6551	Complain: false, Found&: dap))
6552	SetFailed(InitializationSequence::FK_AddressOfOverloadFailed);
6553	else if (Initializer->getType()->isFunctionType() &&
6554	isExprAnUnaddressableFunction(S, E: Initializer))
6555	SetFailed(InitializationSequence::FK_AddressOfUnaddressableFunction);
6556	else
6557	SetFailed(InitializationSequence::FK_ConversionFailed);
6558	} else {
6559	AddConversionSequenceStep(ICS, T: DestType, TopLevelOfInitList);
6560
6561	MaybeProduceObjCObject(S, Sequence&: *this, Entity);
6562	}
6563	}
6564
6565	InitializationSequence::~InitializationSequence() {
6566	for (auto &S : Steps)
6567	S.Destroy();
6568	}
6569
6570	//===----------------------------------------------------------------------===//
6571	// Perform initialization
6572	//===----------------------------------------------------------------------===//
6573	static Sema::AssignmentAction
6574	getAssignmentAction(const InitializedEntity &Entity, bool Diagnose = false) {
6575	switch(Entity.getKind()) {
6576	case InitializedEntity::EK_Variable:
6577	case InitializedEntity::EK_New:
6578	case InitializedEntity::EK_Exception:
6579	case InitializedEntity::EK_Base:
6580	case InitializedEntity::EK_Delegating:
6581	return Sema::AA_Initializing;
6582
6583	case InitializedEntity::EK_Parameter:
6584	if (Entity.getDecl() &&
6585	isa<ObjCMethodDecl>(Entity.getDecl()->getDeclContext()))
6586	return Sema::AA_Sending;
6587
6588	return Sema::AA_Passing;
6589
6590	case InitializedEntity::EK_Parameter_CF_Audited:
6591	if (Entity.getDecl() &&
6592	isa<ObjCMethodDecl>(Entity.getDecl()->getDeclContext()))
6593	return Sema::AA_Sending;
6594
6595	return !Diagnose ? Sema::AA_Passing : Sema::AA_Passing_CFAudited;
6596
6597	case InitializedEntity::EK_Result:
6598	case InitializedEntity::EK_StmtExprResult: // FIXME: Not quite right.
6599	return Sema::AA_Returning;
6600
6601	case InitializedEntity::EK_Temporary:
6602	case InitializedEntity::EK_RelatedResult:
6603	// FIXME: Can we tell apart casting vs. converting?
6604	return Sema::AA_Casting;
6605
6606	case InitializedEntity::EK_TemplateParameter:
6607	// This is really initialization, but refer to it as conversion for
6608	// consistency with CheckConvertedConstantExpression.
6609	return Sema::AA_Converting;
6610
6611	case InitializedEntity::EK_Member:
6612	case InitializedEntity::EK_ParenAggInitMember:
6613	case InitializedEntity::EK_Binding:
6614	case InitializedEntity::EK_ArrayElement:
6615	case InitializedEntity::EK_VectorElement:
6616	case InitializedEntity::EK_ComplexElement:
6617	case InitializedEntity::EK_BlockElement:
6618	case InitializedEntity::EK_LambdaToBlockConversionBlockElement:
6619	case InitializedEntity::EK_LambdaCapture:
6620	case InitializedEntity::EK_CompoundLiteralInit:
6621	return Sema::AA_Initializing;
6622	}
6623
6624	llvm_unreachable("Invalid EntityKind!");
6625	}
6626
6627	/// Whether we should bind a created object as a temporary when
6628	/// initializing the given entity.
6629	static bool shouldBindAsTemporary(const InitializedEntity &Entity) {
6630	switch (Entity.getKind()) {
6631	case InitializedEntity::EK_ArrayElement:
6632	case InitializedEntity::EK_Member:
6633	case InitializedEntity::EK_ParenAggInitMember:
6634	case InitializedEntity::EK_Result:
6635	case InitializedEntity::EK_StmtExprResult:
6636	case InitializedEntity::EK_New:
6637	case InitializedEntity::EK_Variable:
6638	case InitializedEntity::EK_Base:
6639	case InitializedEntity::EK_Delegating:
6640	case InitializedEntity::EK_VectorElement:
6641	case InitializedEntity::EK_ComplexElement:
6642	case InitializedEntity::EK_Exception:
6643	case InitializedEntity::EK_BlockElement:
6644	case InitializedEntity::EK_LambdaToBlockConversionBlockElement:
6645	case InitializedEntity::EK_LambdaCapture:
6646	case InitializedEntity::EK_CompoundLiteralInit:
6647	case InitializedEntity::EK_TemplateParameter:
6648	return false;
6649
6650	case InitializedEntity::EK_Parameter:
6651	case InitializedEntity::EK_Parameter_CF_Audited:
6652	case InitializedEntity::EK_Temporary:
6653	case InitializedEntity::EK_RelatedResult:
6654	case InitializedEntity::EK_Binding:
6655	return true;
6656	}
6657
6658	llvm_unreachable("missed an InitializedEntity kind?");
6659	}
6660
6661	/// Whether the given entity, when initialized with an object
6662	/// created for that initialization, requires destruction.
6663	static bool shouldDestroyEntity(const InitializedEntity &Entity) {
6664	switch (Entity.getKind()) {
6665	case InitializedEntity::EK_Result:
6666	case InitializedEntity::EK_StmtExprResult:
6667	case InitializedEntity::EK_New:
6668	case InitializedEntity::EK_Base:
6669	case InitializedEntity::EK_Delegating:
6670	case InitializedEntity::EK_VectorElement:
6671	case InitializedEntity::EK_ComplexElement:
6672	case InitializedEntity::EK_BlockElement:
6673	case InitializedEntity::EK_LambdaToBlockConversionBlockElement:
6674	case InitializedEntity::EK_LambdaCapture:
6675	return false;
6676
6677	case InitializedEntity::EK_Member:
6678	case InitializedEntity::EK_ParenAggInitMember:
6679	case InitializedEntity::EK_Binding:
6680	case InitializedEntity::EK_Variable:
6681	case InitializedEntity::EK_Parameter:
6682	case InitializedEntity::EK_Parameter_CF_Audited:
6683	case InitializedEntity::EK_TemplateParameter:
6684	case InitializedEntity::EK_Temporary:
6685	case InitializedEntity::EK_ArrayElement:
6686	case InitializedEntity::EK_Exception:
6687	case InitializedEntity::EK_CompoundLiteralInit:
6688	case InitializedEntity::EK_RelatedResult:
6689	return true;
6690	}
6691
6692	llvm_unreachable("missed an InitializedEntity kind?");
6693	}
6694
6695	/// Get the location at which initialization diagnostics should appear.
6696	static SourceLocation getInitializationLoc(const InitializedEntity &Entity,
6697	Expr *Initializer) {
6698	switch (Entity.getKind()) {
6699	case InitializedEntity::EK_Result:
6700	case InitializedEntity::EK_StmtExprResult:
6701	return Entity.getReturnLoc();
6702
6703	case InitializedEntity::EK_Exception:
6704	return Entity.getThrowLoc();
6705
6706	case InitializedEntity::EK_Variable:
6707	case InitializedEntity::EK_Binding:
6708	return Entity.getDecl()->getLocation();
6709
6710	case InitializedEntity::EK_LambdaCapture:
6711	return Entity.getCaptureLoc();
6712
6713	case InitializedEntity::EK_ArrayElement:
6714	case InitializedEntity::EK_Member:
6715	case InitializedEntity::EK_ParenAggInitMember:
6716	case InitializedEntity::EK_Parameter:
6717	case InitializedEntity::EK_Parameter_CF_Audited:
6718	case InitializedEntity::EK_TemplateParameter:
6719	case InitializedEntity::EK_Temporary:
6720	case InitializedEntity::EK_New:
6721	case InitializedEntity::EK_Base:
6722	case InitializedEntity::EK_Delegating:
6723	case InitializedEntity::EK_VectorElement:
6724	case InitializedEntity::EK_ComplexElement:
6725	case InitializedEntity::EK_BlockElement:
6726	case InitializedEntity::EK_LambdaToBlockConversionBlockElement:
6727	case InitializedEntity::EK_CompoundLiteralInit:
6728	case InitializedEntity::EK_RelatedResult:
6729	return Initializer->getBeginLoc();
6730	}
6731	llvm_unreachable("missed an InitializedEntity kind?");
6732	}
6733
6734	/// Make a (potentially elidable) temporary copy of the object
6735	/// provided by the given initializer by calling the appropriate copy
6736	/// constructor.
6737	///
6738	/// \param S The Sema object used for type-checking.
6739	///
6740	/// \param T The type of the temporary object, which must either be
6741	/// the type of the initializer expression or a superclass thereof.
6742	///
6743	/// \param Entity The entity being initialized.
6744	///
6745	/// \param CurInit The initializer expression.
6746	///
6747	/// \param IsExtraneousCopy Whether this is an "extraneous" copy that
6748	/// is permitted in C++03 (but not C++0x) when binding a reference to
6749	/// an rvalue.
6750	///
6751	/// \returns An expression that copies the initializer expression into
6752	/// a temporary object, or an error expression if a copy could not be
6753	/// created.
6754	static ExprResult CopyObject(Sema &S,
6755	QualType T,
6756	const InitializedEntity &Entity,
6757	ExprResult CurInit,
6758	bool IsExtraneousCopy) {
6759	if (CurInit.isInvalid())
6760	return CurInit;
6761	// Determine which class type we're copying to.
6762	Expr *CurInitExpr = (Expr *)CurInit.get();
6763	CXXRecordDecl *Class = nullptr;
6764	if (const RecordType *Record = T->getAs<RecordType>())
6765	Class = cast<CXXRecordDecl>(Val: Record->getDecl());
6766	if (!Class)
6767	return CurInit;
6768
6769	SourceLocation Loc = getInitializationLoc(Entity, Initializer: CurInit.get());
6770
6771	// Make sure that the type we are copying is complete.
6772	if (S.RequireCompleteType(Loc, T, diag::err_temp_copy_incomplete))
6773	return CurInit;
6774
6775	// Perform overload resolution using the class's constructors. Per
6776	// C++11 [dcl.init]p16, second bullet for class types, this initialization
6777	// is direct-initialization.
6778	OverloadCandidateSet CandidateSet(Loc, OverloadCandidateSet::CSK_Normal);
6779	DeclContext::lookup_result Ctors = S.LookupConstructors(Class);
6780
6781	OverloadCandidateSet::iterator Best;
6782	switch (ResolveConstructorOverload(
6783	S, DeclLoc: Loc, Args: CurInitExpr, CandidateSet, DestType: T, Ctors, Best,
6784	/*CopyInitializing=*/false, /*AllowExplicit=*/true,
6785	/*OnlyListConstructors=*/false, /*IsListInit=*/false,
6786	/*RequireActualConstructor=*/false,
6787	/*SecondStepOfCopyInit=*/true)) {
6788	case OR_Success:
6789	break;
6790
6791	case OR_No_Viable_Function:
6792	CandidateSet.NoteCandidates(
6793	PartialDiagnosticAt(
6794	Loc, S.PDiag(IsExtraneousCopy && !S.isSFINAEContext()
6795	? diag::ext_rvalue_to_reference_temp_copy_no_viable
6796	: diag::err_temp_copy_no_viable)
6797	<< (int)Entity.getKind() << CurInitExpr->getType()
6798	<< CurInitExpr->getSourceRange()),
6799	S, OCD_AllCandidates, CurInitExpr);
6800	if (!IsExtraneousCopy || S.isSFINAEContext())
6801	return ExprError();
6802	return CurInit;
6803
6804	case OR_Ambiguous:
6805	CandidateSet.NoteCandidates(
6806	PartialDiagnosticAt(Loc, S.PDiag(diag::err_temp_copy_ambiguous)
6807	<< (int)Entity.getKind()
6808	<< CurInitExpr->getType()
6809	<< CurInitExpr->getSourceRange()),
6810	S, OCD_AmbiguousCandidates, CurInitExpr);
6811	return ExprError();
6812
6813	case OR_Deleted:
6814	S.Diag(Loc, diag::err_temp_copy_deleted)
6815	<< (int)Entity.getKind() << CurInitExpr->getType()
6816	<< CurInitExpr->getSourceRange();
6817	S.NoteDeletedFunction(FD: Best->Function);
6818	return ExprError();
6819	}
6820
6821	bool HadMultipleCandidates = CandidateSet.size() > 1;
6822
6823	CXXConstructorDecl *Constructor = cast<CXXConstructorDecl>(Val: Best->Function);
6824	SmallVector<Expr*, 8> ConstructorArgs;
6825	CurInit.get(); // Ownership transferred into MultiExprArg, below.
6826
6827	S.CheckConstructorAccess(Loc, D: Constructor, FoundDecl: Best->FoundDecl, Entity,
6828	IsCopyBindingRefToTemp: IsExtraneousCopy);
6829
6830	if (IsExtraneousCopy) {
6831	// If this is a totally extraneous copy for C++03 reference
6832	// binding purposes, just return the original initialization
6833	// expression. We don't generate an (elided) copy operation here
6834	// because doing so would require us to pass down a flag to avoid
6835	// infinite recursion, where each step adds another extraneous,
6836	// elidable copy.
6837
6838	// Instantiate the default arguments of any extra parameters in
6839	// the selected copy constructor, as if we were going to create a
6840	// proper call to the copy constructor.
6841	for (unsigned I = 1, N = Constructor->getNumParams(); I != N; ++I) {
6842	ParmVarDecl *Parm = Constructor->getParamDecl(I);
6843	if (S.RequireCompleteType(Loc, Parm->getType(),
6844	diag::err_call_incomplete_argument))
6845	break;
6846
6847	// Build the default argument expression; we don't actually care
6848	// if this succeeds or not, because this routine will complain
6849	// if there was a problem.
6850	S.BuildCXXDefaultArgExpr(Loc, Constructor, Parm);
6851	}
6852
6853	return CurInitExpr;
6854	}
6855
6856	// Determine the arguments required to actually perform the
6857	// constructor call (we might have derived-to-base conversions, or
6858	// the copy constructor may have default arguments).
6859	if (S.CompleteConstructorCall(Constructor, DeclInitType: T, ArgsPtr: CurInitExpr, Loc,
6860	ConvertedArgs&: ConstructorArgs))
6861	return ExprError();
6862
6863	// C++0x [class.copy]p32:
6864	// When certain criteria are met, an implementation is allowed to
6865	// omit the copy/move construction of a class object, even if the
6866	// copy/move constructor and/or destructor for the object have
6867	// side effects. [...]
6868	// - when a temporary class object that has not been bound to a
6869	// reference (12.2) would be copied/moved to a class object
6870	// with the same cv-unqualified type, the copy/move operation
6871	// can be omitted by constructing the temporary object
6872	// directly into the target of the omitted copy/move
6873	//
6874	// Note that the other three bullets are handled elsewhere. Copy
6875	// elision for return statements and throw expressions are handled as part
6876	// of constructor initialization, while copy elision for exception handlers
6877	// is handled by the run-time.
6878	//
6879	// FIXME: If the function parameter is not the same type as the temporary, we
6880	// should still be able to elide the copy, but we don't have a way to
6881	// represent in the AST how much should be elided in this case.
6882	bool Elidable =
6883	CurInitExpr->isTemporaryObject(Ctx&: S.Context, TempTy: Class) &&
6884	S.Context.hasSameUnqualifiedType(
6885	T1: Best->Function->getParamDecl(i: 0)->getType().getNonReferenceType(),
6886	T2: CurInitExpr->getType());
6887
6888	// Actually perform the constructor call.
6889	CurInit = S.BuildCXXConstructExpr(
6890	ConstructLoc: Loc, DeclInitType: T, FoundDecl: Best->FoundDecl, Constructor, Elidable, Exprs: ConstructorArgs,
6891	HadMultipleCandidates,
6892	/*ListInit*/ IsListInitialization: false,
6893	/*StdInitListInit*/ IsStdInitListInitialization: false,
6894	/*ZeroInit*/ RequiresZeroInit: false, ConstructKind: CXXConstructionKind::Complete, ParenRange: SourceRange());
6895
6896	// If we're supposed to bind temporaries, do so.
6897	if (!CurInit.isInvalid() && shouldBindAsTemporary(Entity))
6898	CurInit = S.MaybeBindToTemporary(E: CurInit.getAs<Expr>());
6899	return CurInit;
6900	}
6901
6902	/// Check whether elidable copy construction for binding a reference to
6903	/// a temporary would have succeeded if we were building in C++98 mode, for
6904	/// -Wc++98-compat.
6905	static void CheckCXX98CompatAccessibleCopy(Sema &S,
6906	const InitializedEntity &Entity,
6907	Expr *CurInitExpr) {
6908	assert(S.getLangOpts().CPlusPlus11);
6909
6910	const RecordType *Record = CurInitExpr->getType()->getAs<RecordType>();
6911	if (!Record)
6912	return;
6913
6914	SourceLocation Loc = getInitializationLoc(Entity, Initializer: CurInitExpr);
6915	if (S.Diags.isIgnored(diag::warn_cxx98_compat_temp_copy, Loc))
6916	return;
6917
6918	// Find constructors which would have been considered.
6919	OverloadCandidateSet CandidateSet(Loc, OverloadCandidateSet::CSK_Normal);
6920	DeclContext::lookup_result Ctors =
6921	S.LookupConstructors(Class: cast<CXXRecordDecl>(Val: Record->getDecl()));
6922
6923	// Perform overload resolution.
6924	OverloadCandidateSet::iterator Best;
6925	OverloadingResult OR = ResolveConstructorOverload(
6926	S, DeclLoc: Loc, Args: CurInitExpr, CandidateSet, DestType: CurInitExpr->getType(), Ctors, Best,
6927	/*CopyInitializing=*/false, /*AllowExplicit=*/true,
6928	/*OnlyListConstructors=*/false, /*IsListInit=*/false,
6929	/*RequireActualConstructor=*/false,
6930	/*SecondStepOfCopyInit=*/true);
6931
6932	PartialDiagnostic Diag = S.PDiag(diag::warn_cxx98_compat_temp_copy)
6933	<< OR << (int)Entity.getKind() << CurInitExpr->getType()
6934	<< CurInitExpr->getSourceRange();
6935
6936	switch (OR) {
6937	case OR_Success:
6938	S.CheckConstructorAccess(Loc, D: cast<CXXConstructorDecl>(Val: Best->Function),
6939	FoundDecl: Best->FoundDecl, Entity, PDiag: Diag);
6940	// FIXME: Check default arguments as far as that's possible.
6941	break;
6942
6943	case OR_No_Viable_Function:
6944	CandidateSet.NoteCandidates(PA: PartialDiagnosticAt(Loc, Diag), S,
6945	OCD: OCD_AllCandidates, Args: CurInitExpr);
6946	break;
6947
6948	case OR_Ambiguous:
6949	CandidateSet.NoteCandidates(PA: PartialDiagnosticAt(Loc, Diag), S,
6950	OCD: OCD_AmbiguousCandidates, Args: CurInitExpr);
6951	break;
6952
6953	case OR_Deleted:
6954	S.Diag(Loc, PD: Diag);
6955	S.NoteDeletedFunction(FD: Best->Function);
6956	break;
6957	}
6958	}
6959
6960	void InitializationSequence::PrintInitLocationNote(Sema &S,
6961	const InitializedEntity &Entity) {
6962	if (Entity.isParamOrTemplateParamKind() && Entity.getDecl()) {
6963	if (Entity.getDecl()->getLocation().isInvalid())
6964	return;
6965
6966	if (Entity.getDecl()->getDeclName())
6967	S.Diag(Entity.getDecl()->getLocation(), diag::note_parameter_named_here)
6968	<< Entity.getDecl()->getDeclName();
6969	else
6970	S.Diag(Entity.getDecl()->getLocation(), diag::note_parameter_here);
6971	}
6972	else if (Entity.getKind() == InitializedEntity::EK_RelatedResult &&
6973	Entity.getMethodDecl())
6974	S.Diag(Entity.getMethodDecl()->getLocation(),
6975	diag::note_method_return_type_change)
6976	<< Entity.getMethodDecl()->getDeclName();
6977	}
6978
6979	/// Returns true if the parameters describe a constructor initialization of
6980	/// an explicit temporary object, e.g. "Point(x, y)".
6981	static bool isExplicitTemporary(const InitializedEntity &Entity,
6982	const InitializationKind &Kind,
6983	unsigned NumArgs) {
6984	switch (Entity.getKind()) {
6985	case InitializedEntity::EK_Temporary:
6986	case InitializedEntity::EK_CompoundLiteralInit:
6987	case InitializedEntity::EK_RelatedResult:
6988	break;
6989	default:
6990	return false;
6991	}
6992
6993	switch (Kind.getKind()) {
6994	case InitializationKind::IK_DirectList:
6995	return true;
6996	// FIXME: Hack to work around cast weirdness.
6997	case InitializationKind::IK_Direct:
6998	case InitializationKind::IK_Value:
6999	return NumArgs != 1;
7000	default:
7001	return false;
7002	}
7003	}
7004
7005	static ExprResult
7006	PerformConstructorInitialization(Sema &S,
7007	const InitializedEntity &Entity,
7008	const InitializationKind &Kind,
7009	MultiExprArg Args,
7010	const InitializationSequence::Step& Step,
7011	bool &ConstructorInitRequiresZeroInit,
7012	bool IsListInitialization,
7013	bool IsStdInitListInitialization,
7014	SourceLocation LBraceLoc,
7015	SourceLocation RBraceLoc) {
7016	unsigned NumArgs = Args.size();
7017	CXXConstructorDecl *Constructor
7018	= cast<CXXConstructorDecl>(Val: Step.Function.Function);
7019	bool HadMultipleCandidates = Step.Function.HadMultipleCandidates;
7020
7021	// Build a call to the selected constructor.
7022	SmallVector<Expr*, 8> ConstructorArgs;
7023	SourceLocation Loc = (Kind.isCopyInit() && Kind.getEqualLoc().isValid())
7024	? Kind.getEqualLoc()
7025	: Kind.getLocation();
7026
7027	if (Kind.getKind() == InitializationKind::IK_Default) {
7028	// Force even a trivial, implicit default constructor to be
7029	// semantically checked. We do this explicitly because we don't build
7030	// the definition for completely trivial constructors.
7031	assert(Constructor->getParent() && "No parent class for constructor.");
7032	if (Constructor->isDefaulted() && Constructor->isDefaultConstructor() &&
7033	Constructor->isTrivial() && !Constructor->isUsed(false)) {
7034	S.runWithSufficientStackSpace(Loc, Fn: [&] {
7035	S.DefineImplicitDefaultConstructor(CurrentLocation: Loc, Constructor);
7036	});
7037	}
7038	}
7039
7040	ExprResult CurInit((Expr *)nullptr);
7041
7042	// C++ [over.match.copy]p1:
7043	// - When initializing a temporary to be bound to the first parameter
7044	// of a constructor that takes a reference to possibly cv-qualified
7045	// T as its first argument, called with a single argument in the
7046	// context of direct-initialization, explicit conversion functions
7047	// are also considered.
7048	bool AllowExplicitConv =
7049	Kind.AllowExplicit() && !Kind.isCopyInit() && Args.size() == 1 &&
7050	hasCopyOrMoveCtorParam(Ctx&: S.Context,
7051	Info: getConstructorInfo(ND: Step.Function.FoundDecl));
7052
7053	// Determine the arguments required to actually perform the constructor
7054	// call.
7055	if (S.CompleteConstructorCall(Constructor, DeclInitType: Step.Type, ArgsPtr: Args, Loc,
7056	ConvertedArgs&: ConstructorArgs, AllowExplicit: AllowExplicitConv,
7057	IsListInitialization))
7058	return ExprError();
7059
7060	if (isExplicitTemporary(Entity, Kind, NumArgs)) {
7061	// An explicitly-constructed temporary, e.g., X(1, 2).
7062	if (S.DiagnoseUseOfDecl(D: Step.Function.FoundDecl, Locs: Loc))
7063	return ExprError();
7064
7065	TypeSourceInfo *TSInfo = Entity.getTypeSourceInfo();
7066	if (!TSInfo)
7067	TSInfo = S.Context.getTrivialTypeSourceInfo(T: Entity.getType(), Loc);
7068	SourceRange ParenOrBraceRange =
7069	(Kind.getKind() == InitializationKind::IK_DirectList)
7070	? SourceRange(LBraceLoc, RBraceLoc)
7071	: Kind.getParenOrBraceRange();
7072
7073	CXXConstructorDecl *CalleeDecl = Constructor;
7074	if (auto *Shadow = dyn_cast<ConstructorUsingShadowDecl>(
7075	Val: Step.Function.FoundDecl.getDecl())) {
7076	CalleeDecl = S.findInheritingConstructor(Loc, BaseCtor: Constructor, DerivedShadow: Shadow);
7077	}
7078	S.MarkFunctionReferenced(Loc, CalleeDecl);
7079
7080	CurInit = S.CheckForImmediateInvocation(
7081	CXXTemporaryObjectExpr::Create(
7082	Ctx: S.Context, Cons: CalleeDecl,
7083	Ty: Entity.getType().getNonLValueExprType(Context: S.Context), TSI: TSInfo,
7084	Args: ConstructorArgs, ParenOrBraceRange, HadMultipleCandidates,
7085	ListInitialization: IsListInitialization, StdInitListInitialization: IsStdInitListInitialization,
7086	ZeroInitialization: ConstructorInitRequiresZeroInit),
7087	CalleeDecl);
7088	} else {
7089	CXXConstructionKind ConstructKind = CXXConstructionKind::Complete;
7090
7091	if (Entity.getKind() == InitializedEntity::EK_Base) {
7092	ConstructKind = Entity.getBaseSpecifier()->isVirtual()
7093	? CXXConstructionKind::VirtualBase
7094	: CXXConstructionKind::NonVirtualBase;
7095	} else if (Entity.getKind() == InitializedEntity::EK_Delegating) {
7096	ConstructKind = CXXConstructionKind::Delegating;
7097	}
7098
7099	// Only get the parenthesis or brace range if it is a list initialization or
7100	// direct construction.
7101	SourceRange ParenOrBraceRange;
7102	if (IsListInitialization)
7103	ParenOrBraceRange = SourceRange(LBraceLoc, RBraceLoc);
7104	else if (Kind.getKind() == InitializationKind::IK_Direct)
7105	ParenOrBraceRange = Kind.getParenOrBraceRange();
7106
7107	// If the entity allows NRVO, mark the construction as elidable
7108	// unconditionally.
7109	if (Entity.allowsNRVO())
7110	CurInit = S.BuildCXXConstructExpr(Loc, Step.Type,
7111	Step.Function.FoundDecl,
7112	Constructor, /*Elidable=*/true,
7113	ConstructorArgs,
7114	HadMultipleCandidates,
7115	IsListInitialization,
7116	IsStdInitListInitialization,
7117	ConstructorInitRequiresZeroInit,
7118	ConstructKind,
7119	ParenOrBraceRange);
7120	else
7121	CurInit = S.BuildCXXConstructExpr(Loc, Step.Type,
7122	Step.Function.FoundDecl,
7123	Constructor,
7124	ConstructorArgs,
7125	HadMultipleCandidates,
7126	IsListInitialization,
7127	IsStdInitListInitialization,
7128	ConstructorInitRequiresZeroInit,
7129	ConstructKind,
7130	ParenOrBraceRange);
7131	}
7132	if (CurInit.isInvalid())
7133	return ExprError();
7134
7135	// Only check access if all of that succeeded.
7136	S.CheckConstructorAccess(Loc, D: Constructor, FoundDecl: Step.Function.FoundDecl, Entity);
7137	if (S.DiagnoseUseOfDecl(D: Step.Function.FoundDecl, Locs: Loc))
7138	return ExprError();
7139
7140	if (const ArrayType *AT = S.Context.getAsArrayType(T: Entity.getType()))
7141	if (checkDestructorReference(ElementType: S.Context.getBaseElementType(VAT: AT), Loc, SemaRef&: S))
7142	return ExprError();
7143
7144	if (shouldBindAsTemporary(Entity))
7145	CurInit = S.MaybeBindToTemporary(E: CurInit.get());
7146
7147	return CurInit;
7148	}
7149
7150	namespace {
7151	enum LifetimeKind {
7152	/// The lifetime of a temporary bound to this entity ends at the end of the
7153	/// full-expression, and that's (probably) fine.
7154	LK_FullExpression,
7155
7156	/// The lifetime of a temporary bound to this entity is extended to the
7157	/// lifeitme of the entity itself.
7158	LK_Extended,
7159
7160	/// The lifetime of a temporary bound to this entity probably ends too soon,
7161	/// because the entity is allocated in a new-expression.
7162	LK_New,
7163
7164	/// The lifetime of a temporary bound to this entity ends too soon, because
7165	/// the entity is a return object.
7166	LK_Return,
7167
7168	/// The lifetime of a temporary bound to this entity ends too soon, because
7169	/// the entity is the result of a statement expression.
7170	LK_StmtExprResult,
7171
7172	/// This is a mem-initializer: if it would extend a temporary (other than via
7173	/// a default member initializer), the program is ill-formed.
7174	LK_MemInitializer,
7175	};
7176	using LifetimeResult =
7177	llvm::PointerIntPair<const InitializedEntity *, 3, LifetimeKind>;
7178	}
7179
7180	/// Determine the declaration which an initialized entity ultimately refers to,
7181	/// for the purpose of lifetime-extending a temporary bound to a reference in
7182	/// the initialization of \p Entity.
7183	static LifetimeResult getEntityLifetime(
7184	const InitializedEntity *Entity,
7185	const InitializedEntity *InitField = nullptr) {
7186	// C++11 [class.temporary]p5:
7187	switch (Entity->getKind()) {
7188	case InitializedEntity::EK_Variable:
7189	// The temporary [...] persists for the lifetime of the reference
7190	return {Entity, LK_Extended};
7191
7192	case InitializedEntity::EK_Member:
7193	// For subobjects, we look at the complete object.
7194	if (Entity->getParent())
7195	return getEntityLifetime(Entity: Entity->getParent(), InitField: Entity);
7196
7197	// except:
7198	// C++17 [class.base.init]p8:
7199	// A temporary expression bound to a reference member in a
7200	// mem-initializer is ill-formed.
7201	// C++17 [class.base.init]p11:
7202	// A temporary expression bound to a reference member from a
7203	// default member initializer is ill-formed.
7204	//
7205	// The context of p11 and its example suggest that it's only the use of a
7206	// default member initializer from a constructor that makes the program
7207	// ill-formed, not its mere existence, and that it can even be used by
7208	// aggregate initialization.
7209	return {Entity, Entity->isDefaultMemberInitializer() ? LK_Extended
7210	: LK_MemInitializer};
7211
7212	case InitializedEntity::EK_Binding:
7213	// Per [dcl.decomp]p3, the binding is treated as a variable of reference
7214	// type.
7215	return {Entity, LK_Extended};
7216
7217	case InitializedEntity::EK_Parameter:
7218	case InitializedEntity::EK_Parameter_CF_Audited:
7219	// -- A temporary bound to a reference parameter in a function call
7220	// persists until the completion of the full-expression containing
7221	// the call.
7222	return {nullptr, LK_FullExpression};
7223
7224	case InitializedEntity::EK_TemplateParameter:
7225	// FIXME: This will always be ill-formed; should we eagerly diagnose it here?
7226	return {nullptr, LK_FullExpression};
7227
7228	case InitializedEntity::EK_Result:
7229	// -- The lifetime of a temporary bound to the returned value in a
7230	// function return statement is not extended; the temporary is
7231	// destroyed at the end of the full-expression in the return statement.
7232	return {nullptr, LK_Return};
7233
7234	case InitializedEntity::EK_StmtExprResult:
7235	// FIXME: Should we lifetime-extend through the result of a statement
7236	// expression?
7237	return {nullptr, LK_StmtExprResult};
7238
7239	case InitializedEntity::EK_New:
7240	// -- A temporary bound to a reference in a new-initializer persists
7241	// until the completion of the full-expression containing the
7242	// new-initializer.
7243	return {nullptr, LK_New};
7244
7245	case InitializedEntity::EK_Temporary:
7246	case InitializedEntity::EK_CompoundLiteralInit:
7247	case InitializedEntity::EK_RelatedResult:
7248	// We don't yet know the storage duration of the surrounding temporary.
7249	// Assume it's got full-expression duration for now, it will patch up our
7250	// storage duration if that's not correct.
7251	return {nullptr, LK_FullExpression};
7252
7253	case InitializedEntity::EK_ArrayElement:
7254	// For subobjects, we look at the complete object.
7255	return getEntityLifetime(Entity: Entity->getParent(), InitField);
7256
7257	case InitializedEntity::EK_Base:
7258	// For subobjects, we look at the complete object.
7259	if (Entity->getParent())
7260	return getEntityLifetime(Entity: Entity->getParent(), InitField);
7261	return {InitField, LK_MemInitializer};
7262
7263	case InitializedEntity::EK_Delegating:
7264	// We can reach this case for aggregate initialization in a constructor:
7265	// struct A { int &&r; };
7266	// struct B : A { B() : A{0} {} };
7267	// In this case, use the outermost field decl as the context.
7268	return {InitField, LK_MemInitializer};
7269
7270	case InitializedEntity::EK_BlockElement:
7271	case InitializedEntity::EK_LambdaToBlockConversionBlockElement:
7272	case InitializedEntity::EK_LambdaCapture:
7273	case InitializedEntity::EK_VectorElement:
7274	case InitializedEntity::EK_ComplexElement:
7275	return {nullptr, LK_FullExpression};
7276
7277	case InitializedEntity::EK_Exception:
7278	// FIXME: Can we diagnose lifetime problems with exceptions?
7279	return {nullptr, LK_FullExpression};
7280
7281	case InitializedEntity::EK_ParenAggInitMember:
7282	// -- A temporary object bound to a reference element of an aggregate of
7283	// class type initialized from a parenthesized expression-list
7284	// [dcl.init, 9.3] persists until the completion of the full-expression
7285	// containing the expression-list.
7286	return {nullptr, LK_FullExpression};
7287	}
7288
7289	llvm_unreachable("unknown entity kind");
7290	}
7291
7292	namespace {
7293	enum ReferenceKind {
7294	/// Lifetime would be extended by a reference binding to a temporary.
7295	RK_ReferenceBinding,
7296	/// Lifetime would be extended by a std::initializer_list object binding to
7297	/// its backing array.
7298	RK_StdInitializerList,
7299	};
7300
7301	/// A temporary or local variable. This will be one of:
7302	/// * A MaterializeTemporaryExpr.
7303	/// * A DeclRefExpr whose declaration is a local.
7304	/// * An AddrLabelExpr.
7305	/// * A BlockExpr for a block with captures.
7306	using Local = Expr*;
7307
7308	/// Expressions we stepped over when looking for the local state. Any steps
7309	/// that would inhibit lifetime extension or take us out of subexpressions of
7310	/// the initializer are included.
7311	struct IndirectLocalPathEntry {
7312	enum EntryKind {
7313	DefaultInit,
7314	AddressOf,
7315	VarInit,
7316	LValToRVal,
7317	LifetimeBoundCall,
7318	TemporaryCopy,
7319	LambdaCaptureInit,
7320	GslReferenceInit,
7321	GslPointerInit
7322	} Kind;
7323	Expr *E;
7324	union {
7325	const Decl *D = nullptr;
7326	const LambdaCapture *Capture;
7327	};
7328	IndirectLocalPathEntry() {}
7329	IndirectLocalPathEntry(EntryKind K, Expr *E) : Kind(K), E(E) {}
7330	IndirectLocalPathEntry(EntryKind K, Expr *E, const Decl *D)
7331	: Kind(K), E(E), D(D) {}
7332	IndirectLocalPathEntry(EntryKind K, Expr *E, const LambdaCapture *Capture)
7333	: Kind(K), E(E), Capture(Capture) {}
7334	};
7335
7336	using IndirectLocalPath = llvm::SmallVectorImpl<IndirectLocalPathEntry>;
7337
7338	struct RevertToOldSizeRAII {
7339	IndirectLocalPath &Path;
7340	unsigned OldSize = Path.size();
7341	RevertToOldSizeRAII(IndirectLocalPath &Path) : Path(Path) {}
7342	~RevertToOldSizeRAII() { Path.resize(N: OldSize); }
7343	};
7344
7345	using LocalVisitor = llvm::function_ref<bool(IndirectLocalPath &Path, Local L,
7346	ReferenceKind RK)>;
7347	}
7348
7349	static bool isVarOnPath(IndirectLocalPath &Path, VarDecl *VD) {
7350	for (auto E : Path)
7351	if (E.Kind == IndirectLocalPathEntry::VarInit && E.D == VD)
7352	return true;
7353	return false;
7354	}
7355
7356	static bool pathContainsInit(IndirectLocalPath &Path) {
7357	return llvm::any_of(Range&: Path, P: [=](IndirectLocalPathEntry E) {
7358	return E.Kind == IndirectLocalPathEntry::DefaultInit ||
7359	E.Kind == IndirectLocalPathEntry::VarInit;
7360	});
7361	}
7362
7363	static void visitLocalsRetainedByInitializer(IndirectLocalPath &Path,
7364	Expr *Init, LocalVisitor Visit,
7365	bool RevisitSubinits,
7366	bool EnableLifetimeWarnings);
7367
7368	static void visitLocalsRetainedByReferenceBinding(IndirectLocalPath &Path,
7369	Expr *Init, ReferenceKind RK,
7370	LocalVisitor Visit,
7371	bool EnableLifetimeWarnings);
7372
7373	template <typename T> static bool isRecordWithAttr(QualType Type) {
7374	if (auto *RD = Type->getAsCXXRecordDecl())
7375	return RD->hasAttr<T>();
7376	return false;
7377	}
7378
7379	// Decl::isInStdNamespace will return false for iterators in some STL
7380	// implementations due to them being defined in a namespace outside of the std
7381	// namespace.
7382	static bool isInStlNamespace(const Decl *D) {
7383	const DeclContext *DC = D->getDeclContext();
7384	if (!DC)
7385	return false;
7386	if (const auto *ND = dyn_cast<NamespaceDecl>(Val: DC))
7387	if (const IdentifierInfo *II = ND->getIdentifier()) {
7388	StringRef Name = II->getName();
7389	if (Name.size() >= 2 && Name.front() == '_' &&
7390	(Name[1] == '_' || isUppercase(c: Name[1])))
7391	return true;
7392	}
7393
7394	return DC->isStdNamespace();
7395	}
7396
7397	static bool shouldTrackImplicitObjectArg(const CXXMethodDecl *Callee) {
7398	if (auto *Conv = dyn_cast_or_null<CXXConversionDecl>(Val: Callee))
7399	if (isRecordWithAttr<PointerAttr>(Conv->getConversionType()))
7400	return true;
7401	if (!isInStlNamespace(Callee->getParent()))
7402	return false;
7403	if (!isRecordWithAttr<PointerAttr>(
7404	Callee->getFunctionObjectParameterType()) &&
7405	!isRecordWithAttr<OwnerAttr>(Callee->getFunctionObjectParameterType()))
7406	return false;
7407	if (Callee->getReturnType()->isPointerType() ||
7408	isRecordWithAttr<PointerAttr>(Callee->getReturnType())) {
7409	if (!Callee->getIdentifier())
7410	return false;
7411	return llvm::StringSwitch<bool>(Callee->getName())
7412	.Cases(S0: "begin", S1: "rbegin", S2: "cbegin", S3: "crbegin", Value: true)
7413	.Cases(S0: "end", S1: "rend", S2: "cend", S3: "crend", Value: true)
7414	.Cases(S0: "c_str", S1: "data", S2: "get", Value: true)
7415	// Map and set types.
7416	.Cases(S0: "find", S1: "equal_range", S2: "lower_bound", S3: "upper_bound", Value: true)
7417	.Default(Value: false);
7418	} else if (Callee->getReturnType()->isReferenceType()) {
7419	if (!Callee->getIdentifier()) {
7420	auto OO = Callee->getOverloadedOperator();
7421	return OO == OverloadedOperatorKind::OO_Subscript ||
7422	OO == OverloadedOperatorKind::OO_Star;
7423	}
7424	return llvm::StringSwitch<bool>(Callee->getName())
7425	.Cases(S0: "front", S1: "back", S2: "at", S3: "top", S4: "value", Value: true)
7426	.Default(Value: false);
7427	}
7428	return false;
7429	}
7430
7431	static bool shouldTrackFirstArgument(const FunctionDecl *FD) {
7432	if (!FD->getIdentifier() || FD->getNumParams() != 1)
7433	return false;
7434	const auto *RD = FD->getParamDecl(i: 0)->getType()->getPointeeCXXRecordDecl();
7435	if (!FD->isInStdNamespace() || !RD || !RD->isInStdNamespace())
7436	return false;
7437	if (!isRecordWithAttr<PointerAttr>(QualType(RD->getTypeForDecl(), 0)) &&
7438	!isRecordWithAttr<OwnerAttr>(QualType(RD->getTypeForDecl(), 0)))
7439	return false;
7440	if (FD->getReturnType()->isPointerType() ||
7441	isRecordWithAttr<PointerAttr>(FD->getReturnType())) {
7442	return llvm::StringSwitch<bool>(FD->getName())
7443	.Cases(S0: "begin", S1: "rbegin", S2: "cbegin", S3: "crbegin", Value: true)
7444	.Cases(S0: "end", S1: "rend", S2: "cend", S3: "crend", Value: true)
7445	.Case(S: "data", Value: true)
7446	.Default(Value: false);
7447	} else if (FD->getReturnType()->isReferenceType()) {
7448	return llvm::StringSwitch<bool>(FD->getName())
7449	.Cases(S0: "get", S1: "any_cast", Value: true)
7450	.Default(Value: false);
7451	}
7452	return false;
7453	}
7454
7455	static void handleGslAnnotatedTypes(IndirectLocalPath &Path, Expr *Call,
7456	LocalVisitor Visit) {
7457	auto VisitPointerArg = [&](const Decl *D, Expr *Arg, bool Value) {
7458	// We are not interested in the temporary base objects of gsl Pointers:
7459	// Temp().ptr; // Here ptr might not dangle.
7460	if (isa<MemberExpr>(Val: Arg->IgnoreImpCasts()))
7461	return;
7462	// Once we initialized a value with a reference, it can no longer dangle.
7463	if (!Value) {
7464	for (const IndirectLocalPathEntry &PE : llvm::reverse(C&: Path)) {
7465	if (PE.Kind == IndirectLocalPathEntry::GslReferenceInit)
7466	continue;
7467	if (PE.Kind == IndirectLocalPathEntry::GslPointerInit)
7468	return;
7469	break;
7470	}
7471	}
7472	Path.push_back(Elt: {Value ? IndirectLocalPathEntry::GslPointerInit
7473	: IndirectLocalPathEntry::GslReferenceInit,
7474	Arg, D});
7475	if (Arg->isGLValue())
7476	visitLocalsRetainedByReferenceBinding(Path, Init: Arg, RK: RK_ReferenceBinding,
7477	Visit,
7478	/*EnableLifetimeWarnings=*/true);
7479	else
7480	visitLocalsRetainedByInitializer(Path, Init: Arg, Visit, RevisitSubinits: true,
7481	/*EnableLifetimeWarnings=*/true);
7482	Path.pop_back();
7483	};
7484
7485	if (auto *MCE = dyn_cast<CXXMemberCallExpr>(Val: Call)) {
7486	const auto *MD = cast_or_null<CXXMethodDecl>(MCE->getDirectCallee());
7487	if (MD && shouldTrackImplicitObjectArg(MD))
7488	VisitPointerArg(MD, MCE->getImplicitObjectArgument(),
7489	!MD->getReturnType()->isReferenceType());
7490	return;
7491	} else if (auto *OCE = dyn_cast<CXXOperatorCallExpr>(Val: Call)) {
7492	FunctionDecl *Callee = OCE->getDirectCallee();
7493	if (Callee && Callee->isCXXInstanceMember() &&
7494	shouldTrackImplicitObjectArg(Callee: cast<CXXMethodDecl>(Val: Callee)))
7495	VisitPointerArg(Callee, OCE->getArg(0),
7496	!Callee->getReturnType()->isReferenceType());
7497	return;
7498	} else if (auto *CE = dyn_cast<CallExpr>(Val: Call)) {
7499	FunctionDecl *Callee = CE->getDirectCallee();
7500	if (Callee && shouldTrackFirstArgument(FD: Callee))
7501	VisitPointerArg(Callee, CE->getArg(Arg: 0),
7502	!Callee->getReturnType()->isReferenceType());
7503	return;
7504	}
7505
7506	if (auto *CCE = dyn_cast<CXXConstructExpr>(Val: Call)) {
7507	const auto *Ctor = CCE->getConstructor();
7508	const CXXRecordDecl *RD = Ctor->getParent();
7509	if (CCE->getNumArgs() > 0 && RD->hasAttr<PointerAttr>())
7510	VisitPointerArg(Ctor->getParamDecl(0), CCE->getArgs()[0], true);
7511	}
7512	}
7513
7514	static bool implicitObjectParamIsLifetimeBound(const FunctionDecl *FD) {
7515	const TypeSourceInfo *TSI = FD->getTypeSourceInfo();
7516	if (!TSI)
7517	return false;
7518	// Don't declare this variable in the second operand of the for-statement;
7519	// GCC miscompiles that by ending its lifetime before evaluating the
7520	// third operand. See gcc.gnu.org/PR86769.
7521	AttributedTypeLoc ATL;
7522	for (TypeLoc TL = TSI->getTypeLoc();
7523	(ATL = TL.getAsAdjusted<AttributedTypeLoc>());
7524	TL = ATL.getModifiedLoc()) {
7525	if (ATL.getAttrAs<LifetimeBoundAttr>())
7526	return true;
7527	}
7528
7529	// Assume that all assignment operators with a "normal" return type return
7530	// *this, that is, an lvalue reference that is the same type as the implicit
7531	// object parameter (or the LHS for a non-member operator$=).
7532	OverloadedOperatorKind OO = FD->getDeclName().getCXXOverloadedOperator();
7533	if (OO == OO_Equal || isCompoundAssignmentOperator(Kind: OO)) {
7534	QualType RetT = FD->getReturnType();
7535	if (RetT->isLValueReferenceType()) {
7536	ASTContext &Ctx = FD->getASTContext();
7537	QualType LHST;
7538	auto *MD = dyn_cast<CXXMethodDecl>(Val: FD);
7539	if (MD && MD->isCXXInstanceMember())
7540	LHST = Ctx.getLValueReferenceType(T: MD->getFunctionObjectParameterType());
7541	else
7542	LHST = MD->getParamDecl(0)->getType();
7543	if (Ctx.hasSameType(T1: RetT, T2: LHST))
7544	return true;
7545	}
7546	}
7547
7548	return false;
7549	}
7550
7551	static void visitLifetimeBoundArguments(IndirectLocalPath &Path, Expr *Call,
7552	LocalVisitor Visit) {
7553	const FunctionDecl *Callee;
7554	ArrayRef<Expr*> Args;
7555
7556	if (auto *CE = dyn_cast<CallExpr>(Val: Call)) {
7557	Callee = CE->getDirectCallee();
7558	Args = llvm::ArrayRef(CE->getArgs(), CE->getNumArgs());
7559	} else {
7560	auto *CCE = cast<CXXConstructExpr>(Val: Call);
7561	Callee = CCE->getConstructor();
7562	Args = llvm::ArrayRef(CCE->getArgs(), CCE->getNumArgs());
7563	}
7564	if (!Callee)
7565	return;
7566
7567	Expr *ObjectArg = nullptr;
7568	if (isa<CXXOperatorCallExpr>(Val: Call) && Callee->isCXXInstanceMember()) {
7569	ObjectArg = Args[0];
7570	Args = Args.slice(N: 1);
7571	} else if (auto *MCE = dyn_cast<CXXMemberCallExpr>(Val: Call)) {
7572	ObjectArg = MCE->getImplicitObjectArgument();
7573	}
7574
7575	auto VisitLifetimeBoundArg = [&](const Decl *D, Expr *Arg) {
7576	Path.push_back(Elt: {IndirectLocalPathEntry::LifetimeBoundCall, Arg, D});
7577	if (Arg->isGLValue())
7578	visitLocalsRetainedByReferenceBinding(Path, Init: Arg, RK: RK_ReferenceBinding,
7579	Visit,
7580	/*EnableLifetimeWarnings=*/false);
7581	else
7582	visitLocalsRetainedByInitializer(Path, Init: Arg, Visit, RevisitSubinits: true,
7583	/*EnableLifetimeWarnings=*/false);
7584	Path.pop_back();
7585	};
7586
7587	bool CheckCoroCall = false;
7588	if (const auto *RD = Callee->getReturnType()->getAsRecordDecl()) {
7589	CheckCoroCall = RD->hasAttr<CoroLifetimeBoundAttr>() &&
7590	RD->hasAttr<CoroReturnTypeAttr>() &&
7591	!Callee->hasAttr<CoroDisableLifetimeBoundAttr>();
7592	}
7593
7594	if (ObjectArg) {
7595	bool CheckCoroObjArg = CheckCoroCall;
7596	// Coroutine lambda objects with empty capture list are not lifetimebound.
7597	if (auto *LE = dyn_cast<LambdaExpr>(Val: ObjectArg->IgnoreImplicit());
7598	LE && LE->captures().empty())
7599	CheckCoroObjArg = false;
7600	// Allow `get_return_object()` as the object param (__promise) is not
7601	// lifetimebound.
7602	if (Sema::CanBeGetReturnObject(FD: Callee))
7603	CheckCoroObjArg = false;
7604	if (implicitObjectParamIsLifetimeBound(FD: Callee) || CheckCoroObjArg)
7605	VisitLifetimeBoundArg(Callee, ObjectArg);
7606	}
7607
7608	for (unsigned I = 0,
7609	N = std::min<unsigned>(a: Callee->getNumParams(), b: Args.size());
7610	I != N; ++I) {
7611	if (CheckCoroCall || Callee->getParamDecl(I)->hasAttr<LifetimeBoundAttr>())
7612	VisitLifetimeBoundArg(Callee->getParamDecl(i: I), Args[I]);
7613	}
7614	}
7615
7616	/// Visit the locals that would be reachable through a reference bound to the
7617	/// glvalue expression \c Init.
7618	static void visitLocalsRetainedByReferenceBinding(IndirectLocalPath &Path,
7619	Expr *Init, ReferenceKind RK,
7620	LocalVisitor Visit,
7621	bool EnableLifetimeWarnings) {
7622	RevertToOldSizeRAII RAII(Path);
7623
7624	// Walk past any constructs which we can lifetime-extend across.
7625	Expr *Old;
7626	do {
7627	Old = Init;
7628
7629	if (auto *FE = dyn_cast<FullExpr>(Val: Init))
7630	Init = FE->getSubExpr();
7631
7632	if (InitListExpr *ILE = dyn_cast<InitListExpr>(Val: Init)) {
7633	// If this is just redundant braces around an initializer, step over it.
7634	if (ILE->isTransparent())
7635	Init = ILE->getInit(Init: 0);
7636	}
7637
7638	// Step over any subobject adjustments; we may have a materialized
7639	// temporary inside them.
7640	Init = const_cast<Expr *>(Init->skipRValueSubobjectAdjustments());
7641
7642	// Per current approach for DR1376, look through casts to reference type
7643	// when performing lifetime extension.
7644	if (CastExpr *CE = dyn_cast<CastExpr>(Val: Init))
7645	if (CE->getSubExpr()->isGLValue())
7646	Init = CE->getSubExpr();
7647
7648	// Per the current approach for DR1299, look through array element access
7649	// on array glvalues when performing lifetime extension.
7650	if (auto *ASE = dyn_cast<ArraySubscriptExpr>(Val: Init)) {
7651	Init = ASE->getBase();
7652	auto *ICE = dyn_cast<ImplicitCastExpr>(Val: Init);
7653	if (ICE && ICE->getCastKind() == CK_ArrayToPointerDecay)
7654	Init = ICE->getSubExpr();
7655	else
7656	// We can't lifetime extend through this but we might still find some
7657	// retained temporaries.
7658	return visitLocalsRetainedByInitializer(Path, Init, Visit, RevisitSubinits: true,
7659	EnableLifetimeWarnings);
7660	}
7661
7662	// Step into CXXDefaultInitExprs so we can diagnose cases where a
7663	// constructor inherits one as an implicit mem-initializer.
7664	if (auto *DIE = dyn_cast<CXXDefaultInitExpr>(Val: Init)) {
7665	Path.push_back(
7666	{IndirectLocalPathEntry::DefaultInit, DIE, DIE->getField()});
7667	Init = DIE->getExpr();
7668	}
7669	} while (Init != Old);
7670
7671	if (auto *MTE = dyn_cast<MaterializeTemporaryExpr>(Val: Init)) {
7672	if (Visit(Path, Local(MTE), RK))
7673	visitLocalsRetainedByInitializer(Path, Init: MTE->getSubExpr(), Visit, RevisitSubinits: true,
7674	EnableLifetimeWarnings);
7675	}
7676
7677	if (isa<CallExpr>(Val: Init)) {
7678	if (EnableLifetimeWarnings)
7679	handleGslAnnotatedTypes(Path, Call: Init, Visit);
7680	return visitLifetimeBoundArguments(Path, Call: Init, Visit);
7681	}
7682
7683	switch (Init->getStmtClass()) {
7684	case Stmt::DeclRefExprClass: {
7685	// If we find the name of a local non-reference parameter, we could have a
7686	// lifetime problem.
7687	auto *DRE = cast<DeclRefExpr>(Val: Init);
7688	auto *VD = dyn_cast<VarDecl>(Val: DRE->getDecl());
7689	if (VD && VD->hasLocalStorage() &&
7690	!DRE->refersToEnclosingVariableOrCapture()) {
7691	if (!VD->getType()->isReferenceType()) {
7692	Visit(Path, Local(DRE), RK);
7693	} else if (isa<ParmVarDecl>(Val: DRE->getDecl())) {
7694	// The lifetime of a reference parameter is unknown; assume it's OK
7695	// for now.
7696	break;
7697	} else if (VD->getInit() && !isVarOnPath(Path, VD)) {
7698	Path.push_back({IndirectLocalPathEntry::VarInit, DRE, VD});
7699	visitLocalsRetainedByReferenceBinding(Path, Init: VD->getInit(),
7700	RK: RK_ReferenceBinding, Visit,
7701	EnableLifetimeWarnings);
7702	}
7703	}
7704	break;
7705	}
7706
7707	case Stmt::UnaryOperatorClass: {
7708	// The only unary operator that make sense to handle here
7709	// is Deref. All others don't resolve to a "name." This includes
7710	// handling all sorts of rvalues passed to a unary operator.
7711	const UnaryOperator *U = cast<UnaryOperator>(Val: Init);
7712	if (U->getOpcode() == UO_Deref)
7713	visitLocalsRetainedByInitializer(Path, Init: U->getSubExpr(), Visit, RevisitSubinits: true,
7714	EnableLifetimeWarnings);
7715	break;
7716	}
7717
7718	case Stmt::OMPArraySectionExprClass: {
7719	visitLocalsRetainedByInitializer(Path,
7720	Init: cast<OMPArraySectionExpr>(Val: Init)->getBase(),
7721	Visit, RevisitSubinits: true, EnableLifetimeWarnings);
7722	break;
7723	}
7724
7725	case Stmt::ConditionalOperatorClass:
7726	case Stmt::BinaryConditionalOperatorClass: {
7727	auto *C = cast<AbstractConditionalOperator>(Val: Init);
7728	if (!C->getTrueExpr()->getType()->isVoidType())
7729	visitLocalsRetainedByReferenceBinding(Path, Init: C->getTrueExpr(), RK, Visit,
7730	EnableLifetimeWarnings);
7731	if (!C->getFalseExpr()->getType()->isVoidType())
7732	visitLocalsRetainedByReferenceBinding(Path, Init: C->getFalseExpr(), RK, Visit,
7733	EnableLifetimeWarnings);
7734	break;
7735	}
7736
7737	// FIXME: Visit the left-hand side of an -> or ->*.
7738
7739	default:
7740	break;
7741	}
7742	}
7743
7744	/// Visit the locals that would be reachable through an object initialized by
7745	/// the prvalue expression \c Init.
7746	static void visitLocalsRetainedByInitializer(IndirectLocalPath &Path,
7747	Expr *Init, LocalVisitor Visit,
7748	bool RevisitSubinits,
7749	bool EnableLifetimeWarnings) {
7750	RevertToOldSizeRAII RAII(Path);
7751
7752	Expr *Old;
7753	do {
7754	Old = Init;
7755
7756	// Step into CXXDefaultInitExprs so we can diagnose cases where a
7757	// constructor inherits one as an implicit mem-initializer.
7758	if (auto *DIE = dyn_cast<CXXDefaultInitExpr>(Val: Init)) {
7759	Path.push_back({IndirectLocalPathEntry::DefaultInit, DIE, DIE->getField()});
7760	Init = DIE->getExpr();
7761	}
7762
7763	if (auto *FE = dyn_cast<FullExpr>(Val: Init))
7764	Init = FE->getSubExpr();
7765
7766	// Dig out the expression which constructs the extended temporary.
7767	Init = const_cast<Expr *>(Init->skipRValueSubobjectAdjustments());
7768
7769	if (CXXBindTemporaryExpr *BTE = dyn_cast<CXXBindTemporaryExpr>(Val: Init))
7770	Init = BTE->getSubExpr();
7771
7772	Init = Init->IgnoreParens();
7773
7774	// Step over value-preserving rvalue casts.
7775	if (auto *CE = dyn_cast<CastExpr>(Val: Init)) {
7776	switch (CE->getCastKind()) {
7777	case CK_LValueToRValue:
7778	// If we can match the lvalue to a const object, we can look at its
7779	// initializer.
7780	Path.push_back({IndirectLocalPathEntry::LValToRVal, CE});
7781	return visitLocalsRetainedByReferenceBinding(
7782	Path, Init, RK: RK_ReferenceBinding,
7783	Visit: [&](IndirectLocalPath &Path, Local L, ReferenceKind RK) -> bool {
7784	if (auto *DRE = dyn_cast<DeclRefExpr>(Val: L)) {
7785	auto *VD = dyn_cast<VarDecl>(Val: DRE->getDecl());
7786	if (VD && VD->getType().isConstQualified() && VD->getInit() &&
7787	!isVarOnPath(Path, VD)) {
7788	Path.push_back({IndirectLocalPathEntry::VarInit, DRE, VD});
7789	visitLocalsRetainedByInitializer(Path, Init: VD->getInit(), Visit, RevisitSubinits: true,
7790	EnableLifetimeWarnings);
7791	}
7792	} else if (auto *MTE = dyn_cast<MaterializeTemporaryExpr>(Val: L)) {
7793	if (MTE->getType().isConstQualified())
7794	visitLocalsRetainedByInitializer(Path, Init: MTE->getSubExpr(), Visit,
7795	RevisitSubinits: true, EnableLifetimeWarnings);
7796	}
7797	return false;
7798	}, EnableLifetimeWarnings);
7799
7800	// We assume that objects can be retained by pointers cast to integers,
7801	// but not if the integer is cast to floating-point type or to _Complex.
7802	// We assume that casts to 'bool' do not preserve enough information to
7803	// retain a local object.
7804	case CK_NoOp:
7805	case CK_BitCast:
7806	case CK_BaseToDerived:
7807	case CK_DerivedToBase:
7808	case CK_UncheckedDerivedToBase:
7809	case CK_Dynamic:
7810	case CK_ToUnion:
7811	case CK_UserDefinedConversion:
7812	case CK_ConstructorConversion:
7813	case CK_IntegralToPointer:
7814	case CK_PointerToIntegral:
7815	case CK_VectorSplat:
7816	case CK_IntegralCast:
7817	case CK_CPointerToObjCPointerCast:
7818	case CK_BlockPointerToObjCPointerCast:
7819	case CK_AnyPointerToBlockPointerCast:
7820	case CK_AddressSpaceConversion:
7821	break;
7822
7823	case CK_ArrayToPointerDecay:
7824	// Model array-to-pointer decay as taking the address of the array
7825	// lvalue.
7826	Path.push_back({IndirectLocalPathEntry::AddressOf, CE});
7827	return visitLocalsRetainedByReferenceBinding(Path, Init: CE->getSubExpr(),
7828	RK: RK_ReferenceBinding, Visit,
7829	EnableLifetimeWarnings);
7830
7831	default:
7832	return;
7833	}
7834
7835	Init = CE->getSubExpr();
7836	}
7837	} while (Old != Init);
7838
7839	// C++17 [dcl.init.list]p6:
7840	// initializing an initializer_list object from the array extends the
7841	// lifetime of the array exactly like binding a reference to a temporary.
7842	if (auto *ILE = dyn_cast<CXXStdInitializerListExpr>(Val: Init))
7843	return visitLocalsRetainedByReferenceBinding(Path, Init: ILE->getSubExpr(),
7844	RK: RK_StdInitializerList, Visit,
7845	EnableLifetimeWarnings);
7846
7847	if (InitListExpr *ILE = dyn_cast<InitListExpr>(Val: Init)) {
7848	// We already visited the elements of this initializer list while
7849	// performing the initialization. Don't visit them again unless we've
7850	// changed the lifetime of the initialized entity.
7851	if (!RevisitSubinits)
7852	return;
7853
7854	if (ILE->isTransparent())
7855	return visitLocalsRetainedByInitializer(Path, Init: ILE->getInit(Init: 0), Visit,
7856	RevisitSubinits,
7857	EnableLifetimeWarnings);
7858
7859	if (ILE->getType()->isArrayType()) {
7860	for (unsigned I = 0, N = ILE->getNumInits(); I != N; ++I)
7861	visitLocalsRetainedByInitializer(Path, Init: ILE->getInit(Init: I), Visit,
7862	RevisitSubinits,
7863	EnableLifetimeWarnings);
7864	return;
7865	}
7866
7867	if (CXXRecordDecl *RD = ILE->getType()->getAsCXXRecordDecl()) {
7868	assert(RD->isAggregate() && "aggregate init on non-aggregate");
7869
7870	// If we lifetime-extend a braced initializer which is initializing an
7871	// aggregate, and that aggregate contains reference members which are
7872	// bound to temporaries, those temporaries are also lifetime-extended.
7873	if (RD->isUnion() && ILE->getInitializedFieldInUnion() &&
7874	ILE->getInitializedFieldInUnion()->getType()->isReferenceType())
7875	visitLocalsRetainedByReferenceBinding(Path, Init: ILE->getInit(Init: 0),
7876	RK: RK_ReferenceBinding, Visit,
7877	EnableLifetimeWarnings);
7878	else {
7879	unsigned Index = 0;
7880	for (; Index < RD->getNumBases() && Index < ILE->getNumInits(); ++Index)
7881	visitLocalsRetainedByInitializer(Path, Init: ILE->getInit(Init: Index), Visit,
7882	RevisitSubinits,
7883	EnableLifetimeWarnings);
7884	for (const auto *I : RD->fields()) {
7885	if (Index >= ILE->getNumInits())
7886	break;
7887	if (I->isUnnamedBitfield())
7888	continue;
7889	Expr *SubInit = ILE->getInit(Index);
7890	if (I->getType()->isReferenceType())
7891	visitLocalsRetainedByReferenceBinding(Path, SubInit,
7892	RK_ReferenceBinding, Visit,
7893	EnableLifetimeWarnings);
7894	else
7895	// This might be either aggregate-initialization of a member or
7896	// initialization of a std::initializer_list object. Regardless,
7897	// we should recursively lifetime-extend that initializer.
7898	visitLocalsRetainedByInitializer(Path, SubInit, Visit,
7899	RevisitSubinits,
7900	EnableLifetimeWarnings);
7901	++Index;
7902	}
7903	}
7904	}
7905	return;
7906	}
7907
7908	// The lifetime of an init-capture is that of the closure object constructed
7909	// by a lambda-expression.
7910	if (auto *LE = dyn_cast<LambdaExpr>(Val: Init)) {
7911	LambdaExpr::capture_iterator CapI = LE->capture_begin();
7912	for (Expr *E : LE->capture_inits()) {
7913	assert(CapI != LE->capture_end());
7914	const LambdaCapture &Cap = *CapI++;
7915	if (!E)
7916	continue;
7917	if (Cap.capturesVariable())
7918	Path.push_back(Elt: {IndirectLocalPathEntry::LambdaCaptureInit, E, &Cap});
7919	if (E->isGLValue())
7920	visitLocalsRetainedByReferenceBinding(Path, Init: E, RK: RK_ReferenceBinding,
7921	Visit, EnableLifetimeWarnings);
7922	else
7923	visitLocalsRetainedByInitializer(Path, Init: E, Visit, RevisitSubinits: true,
7924	EnableLifetimeWarnings);
7925	if (Cap.capturesVariable())
7926	Path.pop_back();
7927	}
7928	}
7929
7930	// Assume that a copy or move from a temporary references the same objects
7931	// that the temporary does.
7932	if (auto *CCE = dyn_cast<CXXConstructExpr>(Val: Init)) {
7933	if (CCE->getConstructor()->isCopyOrMoveConstructor()) {
7934	if (auto *MTE = dyn_cast<MaterializeTemporaryExpr>(Val: CCE->getArg(Arg: 0))) {
7935	Expr *Arg = MTE->getSubExpr();
7936	Path.push_back({IndirectLocalPathEntry::TemporaryCopy, Arg,
7937	CCE->getConstructor()});
7938	visitLocalsRetainedByInitializer(Path, Init: Arg, Visit, RevisitSubinits: true,
7939	/*EnableLifetimeWarnings*/false);
7940	Path.pop_back();
7941	}
7942	}
7943	}
7944
7945	if (isa<CallExpr>(Val: Init) || isa<CXXConstructExpr>(Val: Init)) {
7946	if (EnableLifetimeWarnings)
7947	handleGslAnnotatedTypes(Path, Call: Init, Visit);
7948	return visitLifetimeBoundArguments(Path, Call: Init, Visit);
7949	}
7950
7951	switch (Init->getStmtClass()) {
7952	case Stmt::UnaryOperatorClass: {
7953	auto *UO = cast<UnaryOperator>(Val: Init);
7954	// If the initializer is the address of a local, we could have a lifetime
7955	// problem.
7956	if (UO->getOpcode() == UO_AddrOf) {
7957	// If this is &rvalue, then it's ill-formed and we have already diagnosed
7958	// it. Don't produce a redundant warning about the lifetime of the
7959	// temporary.
7960	if (isa<MaterializeTemporaryExpr>(Val: UO->getSubExpr()))
7961	return;
7962
7963	Path.push_back({IndirectLocalPathEntry::AddressOf, UO});
7964	visitLocalsRetainedByReferenceBinding(Path, Init: UO->getSubExpr(),
7965	RK: RK_ReferenceBinding, Visit,
7966	EnableLifetimeWarnings);
7967	}
7968	break;
7969	}
7970
7971	case Stmt::BinaryOperatorClass: {
7972	// Handle pointer arithmetic.
7973	auto *BO = cast<BinaryOperator>(Val: Init);
7974	BinaryOperatorKind BOK = BO->getOpcode();
7975	if (!BO->getType()->isPointerType() || (BOK != BO_Add && BOK != BO_Sub))
7976	break;
7977
7978	if (BO->getLHS()->getType()->isPointerType())
7979	visitLocalsRetainedByInitializer(Path, Init: BO->getLHS(), Visit, RevisitSubinits: true,
7980	EnableLifetimeWarnings);
7981	else if (BO->getRHS()->getType()->isPointerType())
7982	visitLocalsRetainedByInitializer(Path, Init: BO->getRHS(), Visit, RevisitSubinits: true,
7983	EnableLifetimeWarnings);
7984	break;
7985	}
7986
7987	case Stmt::ConditionalOperatorClass:
7988	case Stmt::BinaryConditionalOperatorClass: {
7989	auto *C = cast<AbstractConditionalOperator>(Val: Init);
7990	// In C++, we can have a throw-expression operand, which has 'void' type
7991	// and isn't interesting from a lifetime perspective.
7992	if (!C->getTrueExpr()->getType()->isVoidType())
7993	visitLocalsRetainedByInitializer(Path, Init: C->getTrueExpr(), Visit, RevisitSubinits: true,
7994	EnableLifetimeWarnings);
7995	if (!C->getFalseExpr()->getType()->isVoidType())
7996	visitLocalsRetainedByInitializer(Path, Init: C->getFalseExpr(), Visit, RevisitSubinits: true,
7997	EnableLifetimeWarnings);
7998	break;
7999	}
8000
8001	case Stmt::BlockExprClass:
8002	if (cast<BlockExpr>(Val: Init)->getBlockDecl()->hasCaptures()) {
8003	// This is a local block, whose lifetime is that of the function.
8004	Visit(Path, Local(cast<BlockExpr>(Val: Init)), RK_ReferenceBinding);
8005	}
8006	break;
8007
8008	case Stmt::AddrLabelExprClass:
8009	// We want to warn if the address of a label would escape the function.
8010	Visit(Path, Local(cast<AddrLabelExpr>(Val: Init)), RK_ReferenceBinding);
8011	break;
8012
8013	default:
8014	break;
8015	}
8016	}
8017
8018	/// Whether a path to an object supports lifetime extension.
8019	enum PathLifetimeKind {
8020	/// Lifetime-extend along this path.
8021	Extend,
8022	/// We should lifetime-extend, but we don't because (due to technical
8023	/// limitations) we can't. This happens for default member initializers,
8024	/// which we don't clone for every use, so we don't have a unique
8025	/// MaterializeTemporaryExpr to update.
8026	ShouldExtend,
8027	/// Do not lifetime extend along this path.
8028	NoExtend
8029	};
8030
8031	/// Determine whether this is an indirect path to a temporary that we are
8032	/// supposed to lifetime-extend along.
8033	static PathLifetimeKind
8034	shouldLifetimeExtendThroughPath(const IndirectLocalPath &Path) {
8035	PathLifetimeKind Kind = PathLifetimeKind::Extend;
8036	for (auto Elem : Path) {
8037	if (Elem.Kind == IndirectLocalPathEntry::DefaultInit)
8038	Kind = PathLifetimeKind::ShouldExtend;
8039	else if (Elem.Kind != IndirectLocalPathEntry::LambdaCaptureInit)
8040	return PathLifetimeKind::NoExtend;
8041	}
8042	return Kind;
8043	}
8044
8045	/// Find the range for the first interesting entry in the path at or after I.
8046	static SourceRange nextPathEntryRange(const IndirectLocalPath &Path, unsigned I,
8047	Expr *E) {
8048	for (unsigned N = Path.size(); I != N; ++I) {
8049	switch (Path[I].Kind) {
8050	case IndirectLocalPathEntry::AddressOf:
8051	case IndirectLocalPathEntry::LValToRVal:
8052	case IndirectLocalPathEntry::LifetimeBoundCall:
8053	case IndirectLocalPathEntry::TemporaryCopy:
8054	case IndirectLocalPathEntry::GslReferenceInit:
8055	case IndirectLocalPathEntry::GslPointerInit:
8056	// These exist primarily to mark the path as not permitting or
8057	// supporting lifetime extension.
8058	break;
8059
8060	case IndirectLocalPathEntry::VarInit:
8061	if (cast<VarDecl>(Val: Path[I].D)->isImplicit())
8062	return SourceRange();
8063	[[fallthrough]];
8064	case IndirectLocalPathEntry::DefaultInit:
8065	return Path[I].E->getSourceRange();
8066
8067	case IndirectLocalPathEntry::LambdaCaptureInit:
8068	if (!Path[I].Capture->capturesVariable())
8069	continue;
8070	return Path[I].E->getSourceRange();
8071	}
8072	}
8073	return E->getSourceRange();
8074	}
8075
8076	static bool pathOnlyInitializesGslPointer(IndirectLocalPath &Path) {
8077	for (const auto &It : llvm::reverse(C&: Path)) {
8078	if (It.Kind == IndirectLocalPathEntry::VarInit)
8079	continue;
8080	if (It.Kind == IndirectLocalPathEntry::AddressOf)
8081	continue;
8082	if (It.Kind == IndirectLocalPathEntry::LifetimeBoundCall)
8083	continue;
8084	return It.Kind == IndirectLocalPathEntry::GslPointerInit ||
8085	It.Kind == IndirectLocalPathEntry::GslReferenceInit;
8086	}
8087	return false;
8088	}
8089
8090	void Sema::checkInitializerLifetime(const InitializedEntity &Entity,
8091	Expr *Init) {
8092	LifetimeResult LR = getEntityLifetime(Entity: &Entity);
8093	LifetimeKind LK = LR.getInt();
8094	const InitializedEntity *ExtendingEntity = LR.getPointer();
8095
8096	// If this entity doesn't have an interesting lifetime, don't bother looking
8097	// for temporaries within its initializer.
8098	if (LK == LK_FullExpression)
8099	return;
8100
8101	auto TemporaryVisitor = [&](IndirectLocalPath &Path, Local L,
8102	ReferenceKind RK) -> bool {
8103	SourceRange DiagRange = nextPathEntryRange(Path, I: 0, E: L);
8104	SourceLocation DiagLoc = DiagRange.getBegin();
8105
8106	auto *MTE = dyn_cast<MaterializeTemporaryExpr>(Val: L);
8107
8108	bool IsGslPtrInitWithGslTempOwner = false;
8109	bool IsLocalGslOwner = false;
8110	if (pathOnlyInitializesGslPointer(Path)) {
8111	if (isa<DeclRefExpr>(Val: L)) {
8112	// We do not want to follow the references when returning a pointer originating
8113	// from a local owner to avoid the following false positive:
8114	// int &p = *localUniquePtr;
8115	// someContainer.add(std::move(localUniquePtr));
8116	// return p;
8117	IsLocalGslOwner = isRecordWithAttr<OwnerAttr>(L->getType());
8118	if (pathContainsInit(Path) || !IsLocalGslOwner)
8119	return false;
8120	} else {
8121	IsGslPtrInitWithGslTempOwner = MTE && !MTE->getExtendingDecl() &&
8122	isRecordWithAttr<OwnerAttr>(MTE->getType());
8123	// Skipping a chain of initializing gsl::Pointer annotated objects.
8124	// We are looking only for the final source to find out if it was
8125	// a local or temporary owner or the address of a local variable/param.
8126	if (!IsGslPtrInitWithGslTempOwner)
8127	return true;
8128	}
8129	}
8130
8131	switch (LK) {
8132	case LK_FullExpression:
8133	llvm_unreachable("already handled this");
8134
8135	case LK_Extended: {
8136	if (!MTE) {
8137	// The initialized entity has lifetime beyond the full-expression,
8138	// and the local entity does too, so don't warn.
8139	//
8140	// FIXME: We should consider warning if a static / thread storage
8141	// duration variable retains an automatic storage duration local.
8142	return false;
8143	}
8144
8145	if (IsGslPtrInitWithGslTempOwner && DiagLoc.isValid()) {
8146	Diag(DiagLoc, diag::warn_dangling_lifetime_pointer) << DiagRange;
8147	return false;
8148	}
8149
8150	switch (shouldLifetimeExtendThroughPath(Path)) {
8151	case PathLifetimeKind::Extend:
8152	// Update the storage duration of the materialized temporary.
8153	// FIXME: Rebuild the expression instead of mutating it.
8154	MTE->setExtendingDecl(ExtendedBy: ExtendingEntity->getDecl(),
8155	ManglingNumber: ExtendingEntity->allocateManglingNumber());
8156	// Also visit the temporaries lifetime-extended by this initializer.
8157	return true;
8158
8159	case PathLifetimeKind::ShouldExtend:
8160	// We're supposed to lifetime-extend the temporary along this path (per
8161	// the resolution of DR1815), but we don't support that yet.
8162	//
8163	// FIXME: Properly handle this situation. Perhaps the easiest approach
8164	// would be to clone the initializer expression on each use that would
8165	// lifetime extend its temporaries.
8166	Diag(DiagLoc, diag::warn_unsupported_lifetime_extension)
8167	<< RK << DiagRange;
8168	break;
8169
8170	case PathLifetimeKind::NoExtend:
8171	// If the path goes through the initialization of a variable or field,
8172	// it can't possibly reach a temporary created in this full-expression.
8173	// We will have already diagnosed any problems with the initializer.
8174	if (pathContainsInit(Path))
8175	return false;
8176
8177	Diag(DiagLoc, diag::warn_dangling_variable)
8178	<< RK << !Entity.getParent()
8179	<< ExtendingEntity->getDecl()->isImplicit()
8180	<< ExtendingEntity->getDecl() << Init->isGLValue() << DiagRange;
8181	break;
8182	}
8183	break;
8184	}
8185
8186	case LK_MemInitializer: {
8187	if (isa<MaterializeTemporaryExpr>(Val: L)) {
8188	// Under C++ DR1696, if a mem-initializer (or a default member
8189	// initializer used by the absence of one) would lifetime-extend a
8190	// temporary, the program is ill-formed.
8191	if (auto *ExtendingDecl =
8192	ExtendingEntity ? ExtendingEntity->getDecl() : nullptr) {
8193	if (IsGslPtrInitWithGslTempOwner) {
8194	Diag(DiagLoc, diag::warn_dangling_lifetime_pointer_member)
8195	<< ExtendingDecl << DiagRange;
8196	Diag(ExtendingDecl->getLocation(),
8197	diag::note_ref_or_ptr_member_declared_here)
8198	<< true;
8199	return false;
8200	}
8201	bool IsSubobjectMember = ExtendingEntity != &Entity;
8202	Diag(DiagLoc, shouldLifetimeExtendThroughPath(Path) !=
8203	PathLifetimeKind::NoExtend
8204	? diag::err_dangling_member
8205	: diag::warn_dangling_member)
8206	<< ExtendingDecl << IsSubobjectMember << RK << DiagRange;
8207	// Don't bother adding a note pointing to the field if we're inside
8208	// its default member initializer; our primary diagnostic points to
8209	// the same place in that case.
8210	if (Path.empty() ||
8211	Path.back().Kind != IndirectLocalPathEntry::DefaultInit) {
8212	Diag(ExtendingDecl->getLocation(),
8213	diag::note_lifetime_extending_member_declared_here)
8214	<< RK << IsSubobjectMember;
8215	}
8216	} else {
8217	// We have a mem-initializer but no particular field within it; this
8218	// is either a base class or a delegating initializer directly
8219	// initializing the base-class from something that doesn't live long
8220	// enough.
8221	//
8222	// FIXME: Warn on this.
8223	return false;
8224	}
8225	} else {
8226	// Paths via a default initializer can only occur during error recovery
8227	// (there's no other way that a default initializer can refer to a
8228	// local). Don't produce a bogus warning on those cases.
8229	if (pathContainsInit(Path))
8230	return false;
8231
8232	// Suppress false positives for code like the one below:
8233	// Ctor(unique_ptr<T> up) : member(*up), member2(move(up)) {}
8234	if (IsLocalGslOwner && pathOnlyInitializesGslPointer(Path))
8235	return false;
8236
8237	auto *DRE = dyn_cast<DeclRefExpr>(Val: L);
8238	auto *VD = DRE ? dyn_cast<VarDecl>(Val: DRE->getDecl()) : nullptr;
8239	if (!VD) {
8240	// A member was initialized to a local block.
8241	// FIXME: Warn on this.
8242	return false;
8243	}
8244
8245	if (auto *Member =
8246	ExtendingEntity ? ExtendingEntity->getDecl() : nullptr) {
8247	bool IsPointer = !Member->getType()->isReferenceType();
8248	Diag(DiagLoc, IsPointer ? diag::warn_init_ptr_member_to_parameter_addr
8249	: diag::warn_bind_ref_member_to_parameter)
8250	<< Member << VD << isa<ParmVarDecl>(VD) << DiagRange;
8251	Diag(Member->getLocation(),
8252	diag::note_ref_or_ptr_member_declared_here)
8253	<< (unsigned)IsPointer;
8254	}
8255	}
8256	break;
8257	}
8258
8259	case LK_New:
8260	if (isa<MaterializeTemporaryExpr>(Val: L)) {
8261	if (IsGslPtrInitWithGslTempOwner)
8262	Diag(DiagLoc, diag::warn_dangling_lifetime_pointer) << DiagRange;
8263	else
8264	Diag(DiagLoc, RK == RK_ReferenceBinding
8265	? diag::warn_new_dangling_reference
8266	: diag::warn_new_dangling_initializer_list)
8267	<< !Entity.getParent() << DiagRange;
8268	} else {
8269	// We can't determine if the allocation outlives the local declaration.
8270	return false;
8271	}
8272	break;
8273
8274	case LK_Return:
8275	case LK_StmtExprResult:
8276	if (auto *DRE = dyn_cast<DeclRefExpr>(Val: L)) {
8277	// We can't determine if the local variable outlives the statement
8278	// expression.
8279	if (LK == LK_StmtExprResult)
8280	return false;
8281	Diag(DiagLoc, diag::warn_ret_stack_addr_ref)
8282	<< Entity.getType()->isReferenceType() << DRE->getDecl()
8283	<< isa<ParmVarDecl>(DRE->getDecl()) << DiagRange;
8284	} else if (isa<BlockExpr>(Val: L)) {
8285	Diag(DiagLoc, diag::err_ret_local_block) << DiagRange;
8286	} else if (isa<AddrLabelExpr>(Val: L)) {
8287	// Don't warn when returning a label from a statement expression.
8288	// Leaving the scope doesn't end its lifetime.
8289	if (LK == LK_StmtExprResult)
8290	return false;
8291	Diag(DiagLoc, diag::warn_ret_addr_label) << DiagRange;
8292	} else {
8293	Diag(DiagLoc, diag::warn_ret_local_temp_addr_ref)
8294	<< Entity.getType()->isReferenceType() << DiagRange;
8295	}
8296	break;
8297	}
8298
8299	for (unsigned I = 0; I != Path.size(); ++I) {
8300	auto Elem = Path[I];
8301
8302	switch (Elem.Kind) {
8303	case IndirectLocalPathEntry::AddressOf:
8304	case IndirectLocalPathEntry::LValToRVal:
8305	// These exist primarily to mark the path as not permitting or
8306	// supporting lifetime extension.
8307	break;
8308
8309	case IndirectLocalPathEntry::LifetimeBoundCall:
8310	case IndirectLocalPathEntry::TemporaryCopy:
8311	case IndirectLocalPathEntry::GslPointerInit:
8312	case IndirectLocalPathEntry::GslReferenceInit:
8313	// FIXME: Consider adding a note for these.
8314	break;
8315
8316	case IndirectLocalPathEntry::DefaultInit: {
8317	auto *FD = cast<FieldDecl>(Val: Elem.D);
8318	Diag(FD->getLocation(), diag::note_init_with_default_member_initializer)
8319	<< FD << nextPathEntryRange(Path, I + 1, L);
8320	break;
8321	}
8322
8323	case IndirectLocalPathEntry::VarInit: {
8324	const VarDecl *VD = cast<VarDecl>(Val: Elem.D);
8325	Diag(VD->getLocation(), diag::note_local_var_initializer)
8326	<< VD->getType()->isReferenceType()
8327	<< VD->isImplicit() << VD->getDeclName()
8328	<< nextPathEntryRange(Path, I + 1, L);
8329	break;
8330	}
8331
8332	case IndirectLocalPathEntry::LambdaCaptureInit:
8333	if (!Elem.Capture->capturesVariable())
8334	break;
8335	// FIXME: We can't easily tell apart an init-capture from a nested
8336	// capture of an init-capture.
8337	const ValueDecl *VD = Elem.Capture->getCapturedVar();
8338	Diag(Elem.Capture->getLocation(), diag::note_lambda_capture_initializer)
8339	<< VD << VD->isInitCapture() << Elem.Capture->isExplicit()
8340	<< (Elem.Capture->getCaptureKind() == LCK_ByRef) << VD
8341	<< nextPathEntryRange(Path, I + 1, L);
8342	break;
8343	}
8344	}
8345
8346	// We didn't lifetime-extend, so don't go any further; we don't need more
8347	// warnings or errors on inner temporaries within this one's initializer.
8348	return false;
8349	};
8350
8351	bool EnableLifetimeWarnings = !getDiagnostics().isIgnored(
8352	diag::warn_dangling_lifetime_pointer, SourceLocation());
8353	llvm::SmallVector<IndirectLocalPathEntry, 8> Path;
8354	if (Init->isGLValue())
8355	visitLocalsRetainedByReferenceBinding(Path, Init, RK: RK_ReferenceBinding,
8356	Visit: TemporaryVisitor,
8357	EnableLifetimeWarnings);
8358	else
8359	visitLocalsRetainedByInitializer(Path, Init, Visit: TemporaryVisitor, RevisitSubinits: false,
8360	EnableLifetimeWarnings);
8361	}
8362
8363	static void DiagnoseNarrowingInInitList(Sema &S,
8364	const ImplicitConversionSequence &ICS,
8365	QualType PreNarrowingType,
8366	QualType EntityType,
8367	const Expr *PostInit);
8368
8369	/// Provide warnings when std::move is used on construction.
8370	static void CheckMoveOnConstruction(Sema &S, const Expr *InitExpr,
8371	bool IsReturnStmt) {
8372	if (!InitExpr)
8373	return;
8374
8375	if (S.inTemplateInstantiation())
8376	return;
8377
8378	QualType DestType = InitExpr->getType();
8379	if (!DestType->isRecordType())
8380	return;
8381
8382	unsigned DiagID = 0;
8383	if (IsReturnStmt) {
8384	const CXXConstructExpr *CCE =
8385	dyn_cast<CXXConstructExpr>(Val: InitExpr->IgnoreParens());
8386	if (!CCE || CCE->getNumArgs() != 1)
8387	return;
8388
8389	if (!CCE->getConstructor()->isCopyOrMoveConstructor())
8390	return;
8391
8392	InitExpr = CCE->getArg(Arg: 0)->IgnoreImpCasts();
8393	}
8394
8395	// Find the std::move call and get the argument.
8396	const CallExpr *CE = dyn_cast<CallExpr>(Val: InitExpr->IgnoreParens());
8397	if (!CE || !CE->isCallToStdMove())
8398	return;
8399
8400	const Expr *Arg = CE->getArg(Arg: 0)->IgnoreImplicit();
8401
8402	if (IsReturnStmt) {
8403	const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Val: Arg->IgnoreParenImpCasts());
8404	if (!DRE || DRE->refersToEnclosingVariableOrCapture())
8405	return;
8406
8407	const VarDecl *VD = dyn_cast<VarDecl>(Val: DRE->getDecl());
8408	if (!VD || !VD->hasLocalStorage())
8409	return;
8410
8411	// __block variables are not moved implicitly.
8412	if (VD->hasAttr<BlocksAttr>())
8413	return;
8414
8415	QualType SourceType = VD->getType();
8416	if (!SourceType->isRecordType())
8417	return;
8418
8419	if (!S.Context.hasSameUnqualifiedType(T1: DestType, T2: SourceType)) {
8420	return;
8421	}
8422
8423	// If we're returning a function parameter, copy elision
8424	// is not possible.
8425	if (isa<ParmVarDecl>(VD))
8426	DiagID = diag::warn_redundant_move_on_return;
8427	else
8428	DiagID = diag::warn_pessimizing_move_on_return;
8429	} else {
8430	DiagID = diag::warn_pessimizing_move_on_initialization;
8431	const Expr *ArgStripped = Arg->IgnoreImplicit()->IgnoreParens();
8432	if (!ArgStripped->isPRValue() || !ArgStripped->getType()->isRecordType())
8433	return;
8434	}
8435
8436	S.Diag(Loc: CE->getBeginLoc(), DiagID);
8437
8438	// Get all the locations for a fix-it. Don't emit the fix-it if any location
8439	// is within a macro.
8440	SourceLocation CallBegin = CE->getCallee()->getBeginLoc();
8441	if (CallBegin.isMacroID())
8442	return;
8443	SourceLocation RParen = CE->getRParenLoc();
8444	if (RParen.isMacroID())
8445	return;
8446	SourceLocation LParen;
8447	SourceLocation ArgLoc = Arg->getBeginLoc();
8448
8449	// Special testing for the argument location. Since the fix-it needs the
8450	// location right before the argument, the argument location can be in a
8451	// macro only if it is at the beginning of the macro.
8452	while (ArgLoc.isMacroID() &&
8453	S.getSourceManager().isAtStartOfImmediateMacroExpansion(Loc: ArgLoc)) {
8454	ArgLoc = S.getSourceManager().getImmediateExpansionRange(Loc: ArgLoc).getBegin();
8455	}
8456
8457	if (LParen.isMacroID())
8458	return;
8459
8460	LParen = ArgLoc.getLocWithOffset(Offset: -1);
8461
8462	S.Diag(CE->getBeginLoc(), diag::note_remove_move)
8463	<< FixItHint::CreateRemoval(SourceRange(CallBegin, LParen))
8464	<< FixItHint::CreateRemoval(SourceRange(RParen, RParen));
8465	}
8466
8467	static void CheckForNullPointerDereference(Sema &S, const Expr *E) {
8468	// Check to see if we are dereferencing a null pointer. If so, this is
8469	// undefined behavior, so warn about it. This only handles the pattern
8470	// "*null", which is a very syntactic check.
8471	if (const UnaryOperator *UO = dyn_cast<UnaryOperator>(Val: E->IgnoreParenCasts()))
8472	if (UO->getOpcode() == UO_Deref &&
8473	UO->getSubExpr()->IgnoreParenCasts()->
8474	isNullPointerConstant(Ctx&: S.Context, NPC: Expr::NPC_ValueDependentIsNotNull)) {
8475	S.DiagRuntimeBehavior(UO->getOperatorLoc(), UO,
8476	S.PDiag(diag::warn_binding_null_to_reference)
8477	<< UO->getSubExpr()->getSourceRange());
8478	}
8479	}
8480
8481	MaterializeTemporaryExpr *
8482	Sema::CreateMaterializeTemporaryExpr(QualType T, Expr *Temporary,
8483	bool BoundToLvalueReference) {
8484	auto MTE = new (Context)
8485	MaterializeTemporaryExpr(T, Temporary, BoundToLvalueReference);
8486
8487	// Order an ExprWithCleanups for lifetime marks.
8488	//
8489	// TODO: It'll be good to have a single place to check the access of the
8490	// destructor and generate ExprWithCleanups for various uses. Currently these
8491	// are done in both CreateMaterializeTemporaryExpr and MaybeBindToTemporary,
8492	// but there may be a chance to merge them.
8493	Cleanup.setExprNeedsCleanups(false);
8494	if (isInLifetimeExtendingContext()) {
8495	auto &Record = ExprEvalContexts.back();
8496	Record.ForRangeLifetimeExtendTemps.push_back(Elt: MTE);
8497	}
8498	return MTE;
8499	}
8500
8501	ExprResult Sema::TemporaryMaterializationConversion(Expr *E) {
8502	// In C++98, we don't want to implicitly create an xvalue.
8503	// FIXME: This means that AST consumers need to deal with "prvalues" that
8504	// denote materialized temporaries. Maybe we should add another ValueKind
8505	// for "xvalue pretending to be a prvalue" for C++98 support.
8506	if (!E->isPRValue() || !getLangOpts().CPlusPlus11)
8507	return E;
8508
8509	// C++1z [conv.rval]/1: T shall be a complete type.
8510	// FIXME: Does this ever matter (can we form a prvalue of incomplete type)?
8511	// If so, we should check for a non-abstract class type here too.
8512	QualType T = E->getType();
8513	if (RequireCompleteType(E->getExprLoc(), T, diag::err_incomplete_type))
8514	return ExprError();
8515
8516	return CreateMaterializeTemporaryExpr(T: E->getType(), Temporary: E, BoundToLvalueReference: false);
8517	}
8518
8519	ExprResult Sema::PerformQualificationConversion(Expr *E, QualType Ty,
8520	ExprValueKind VK,
8521	CheckedConversionKind CCK) {
8522
8523	CastKind CK = CK_NoOp;
8524
8525	if (VK == VK_PRValue) {
8526	auto PointeeTy = Ty->getPointeeType();
8527	auto ExprPointeeTy = E->getType()->getPointeeType();
8528	if (!PointeeTy.isNull() &&
8529	PointeeTy.getAddressSpace() != ExprPointeeTy.getAddressSpace())
8530	CK = CK_AddressSpaceConversion;
8531	} else if (Ty.getAddressSpace() != E->getType().getAddressSpace()) {
8532	CK = CK_AddressSpaceConversion;
8533	}
8534
8535	return ImpCastExprToType(E, Type: Ty, CK, VK, /*BasePath=*/nullptr, CCK);
8536	}
8537
8538	ExprResult InitializationSequence::Perform(Sema &S,
8539	const InitializedEntity &Entity,
8540	const InitializationKind &Kind,
8541	MultiExprArg Args,
8542	QualType *ResultType) {
8543	if (Failed()) {
8544	Diagnose(S, Entity, Kind, Args);
8545	return ExprError();
8546	}
8547	if (!ZeroInitializationFixit.empty()) {
8548	const Decl *D = Entity.getDecl();
8549	const auto *VD = dyn_cast_or_null<VarDecl>(Val: D);
8550	QualType DestType = Entity.getType();
8551
8552	// The initialization would have succeeded with this fixit. Since the fixit
8553	// is on the error, we need to build a valid AST in this case, so this isn't
8554	// handled in the Failed() branch above.
8555	if (!DestType->isRecordType() && VD && VD->isConstexpr()) {
8556	// Use a more useful diagnostic for constexpr variables.
8557	S.Diag(Kind.getLocation(), diag::err_constexpr_var_requires_const_init)
8558	<< VD
8559	<< FixItHint::CreateInsertion(ZeroInitializationFixitLoc,
8560	ZeroInitializationFixit);
8561	} else {
8562	unsigned DiagID = diag::err_default_init_const;
8563	if (S.getLangOpts().MSVCCompat && D && D->hasAttr<SelectAnyAttr>())
8564	DiagID = diag::ext_default_init_const;
8565
8566	S.Diag(Loc: Kind.getLocation(), DiagID)
8567	<< DestType << (bool)DestType->getAs<RecordType>()
8568	<< FixItHint::CreateInsertion(InsertionLoc: ZeroInitializationFixitLoc,
8569	Code: ZeroInitializationFixit);
8570	}
8571	}
8572
8573	if (getKind() == DependentSequence) {
8574	// If the declaration is a non-dependent, incomplete array type
8575	// that has an initializer, then its type will be completed once
8576	// the initializer is instantiated.
8577	if (ResultType && !Entity.getType()->isDependentType() &&
8578	Args.size() == 1) {
8579	QualType DeclType = Entity.getType();
8580	if (const IncompleteArrayType *ArrayT
8581	= S.Context.getAsIncompleteArrayType(T: DeclType)) {
8582	// FIXME: We don't currently have the ability to accurately
8583	// compute the length of an initializer list without
8584	// performing full type-checking of the initializer list
8585	// (since we have to determine where braces are implicitly
8586	// introduced and such). So, we fall back to making the array
8587	// type a dependently-sized array type with no specified
8588	// bound.
8589	if (isa<InitListExpr>(Val: (Expr *)Args[0])) {
8590	SourceRange Brackets;
8591
8592	// Scavange the location of the brackets from the entity, if we can.
8593	if (auto *DD = dyn_cast_or_null<DeclaratorDecl>(Val: Entity.getDecl())) {
8594	if (TypeSourceInfo *TInfo = DD->getTypeSourceInfo()) {
8595	TypeLoc TL = TInfo->getTypeLoc();
8596	if (IncompleteArrayTypeLoc ArrayLoc =
8597	TL.getAs<IncompleteArrayTypeLoc>())
8598	Brackets = ArrayLoc.getBracketsRange();
8599	}
8600	}
8601
8602	*ResultType
8603	= S.Context.getDependentSizedArrayType(EltTy: ArrayT->getElementType(),
8604	/*NumElts=*/nullptr,
8605	ASM: ArrayT->getSizeModifier(),
8606	IndexTypeQuals: ArrayT->getIndexTypeCVRQualifiers(),
8607	Brackets);
8608	}
8609
8610	}
8611	}
8612	if (Kind.getKind() == InitializationKind::IK_Direct &&
8613	!Kind.isExplicitCast()) {
8614	// Rebuild the ParenListExpr.
8615	SourceRange ParenRange = Kind.getParenOrBraceRange();
8616	return S.ActOnParenListExpr(L: ParenRange.getBegin(), R: ParenRange.getEnd(),
8617	Val: Args);
8618	}
8619	assert(Kind.getKind() == InitializationKind::IK_Copy ||
8620	Kind.isExplicitCast() ||
8621	Kind.getKind() == InitializationKind::IK_DirectList);
8622	return ExprResult(Args[0]);
8623	}
8624
8625	// No steps means no initialization.
8626	if (Steps.empty())
8627	return ExprResult((Expr *)nullptr);
8628
8629	if (S.getLangOpts().CPlusPlus11 && Entity.getType()->isReferenceType() &&
8630	Args.size() == 1 && isa<InitListExpr>(Val: Args[0]) &&
8631	!Entity.isParamOrTemplateParamKind()) {
8632	// Produce a C++98 compatibility warning if we are initializing a reference
8633	// from an initializer list. For parameters, we produce a better warning
8634	// elsewhere.
8635	Expr *Init = Args[0];
8636	S.Diag(Init->getBeginLoc(), diag::warn_cxx98_compat_reference_list_init)
8637	<< Init->getSourceRange();
8638	}
8639
8640	if (S.getLangOpts().MicrosoftExt && Args.size() == 1 &&
8641	isa<PredefinedExpr>(Val: Args[0]) && Entity.getType()->isArrayType()) {
8642	// Produce a Microsoft compatibility warning when initializing from a
8643	// predefined expression since MSVC treats predefined expressions as string
8644	// literals.
8645	Expr *Init = Args[0];
8646	S.Diag(Init->getBeginLoc(), diag::ext_init_from_predefined) << Init;
8647	}
8648
8649	// OpenCL v2.0 s6.13.11.1. atomic variables can be initialized in global scope
8650	QualType ETy = Entity.getType();
8651	bool HasGlobalAS = ETy.hasAddressSpace() &&
8652	ETy.getAddressSpace() == LangAS::opencl_global;
8653
8654	if (S.getLangOpts().OpenCLVersion >= 200 &&
8655	ETy->isAtomicType() && !HasGlobalAS &&
8656	Entity.getKind() == InitializedEntity::EK_Variable && Args.size() > 0) {
8657	S.Diag(Args[0]->getBeginLoc(), diag::err_opencl_atomic_init)
8658	<< 1
8659	<< SourceRange(Entity.getDecl()->getBeginLoc(), Args[0]->getEndLoc());
8660	return ExprError();
8661	}
8662
8663	QualType DestType = Entity.getType().getNonReferenceType();
8664	// FIXME: Ugly hack around the fact that Entity.getType() is not
8665	// the same as Entity.getDecl()->getType() in cases involving type merging,
8666	// and we want latter when it makes sense.
8667	if (ResultType)
8668	*ResultType = Entity.getDecl() ? Entity.getDecl()->getType() :
8669	Entity.getType();
8670
8671	ExprResult CurInit((Expr *)nullptr);
8672	SmallVector<Expr*, 4> ArrayLoopCommonExprs;
8673
8674	// HLSL allows vector initialization to function like list initialization, but
8675	// use the syntax of a C++-like constructor.
8676	bool IsHLSLVectorInit = S.getLangOpts().HLSL && DestType->isExtVectorType() &&
8677	isa<InitListExpr>(Val: Args[0]);
8678	(void)IsHLSLVectorInit;
8679
8680	// For initialization steps that start with a single initializer,
8681	// grab the only argument out the Args and place it into the "current"
8682	// initializer.
8683	switch (Steps.front().Kind) {
8684	case SK_ResolveAddressOfOverloadedFunction:
8685	case SK_CastDerivedToBasePRValue:
8686	case SK_CastDerivedToBaseXValue:
8687	case SK_CastDerivedToBaseLValue:
8688	case SK_BindReference:
8689	case SK_BindReferenceToTemporary:
8690	case SK_FinalCopy:
8691	case SK_ExtraneousCopyToTemporary:
8692	case SK_UserConversion:
8693	case SK_QualificationConversionLValue:
8694	case SK_QualificationConversionXValue:
8695	case SK_QualificationConversionPRValue:
8696	case SK_FunctionReferenceConversion:
8697	case SK_AtomicConversion:
8698	case SK_ConversionSequence:
8699	case SK_ConversionSequenceNoNarrowing:
8700	case SK_ListInitialization:
8701	case SK_UnwrapInitList:
8702	case SK_RewrapInitList:
8703	case SK_CAssignment:
8704	case SK_StringInit:
8705	case SK_ObjCObjectConversion:
8706	case SK_ArrayLoopIndex:
8707	case SK_ArrayLoopInit:
8708	case SK_ArrayInit:
8709	case SK_GNUArrayInit:
8710	case SK_ParenthesizedArrayInit:
8711	case SK_PassByIndirectCopyRestore:
8712	case SK_PassByIndirectRestore:
8713	case SK_ProduceObjCObject:
8714	case SK_StdInitializerList:
8715	case SK_OCLSamplerInit:
8716	case SK_OCLZeroOpaqueType: {
8717	assert(Args.size() == 1 || IsHLSLVectorInit);
8718	CurInit = Args[0];
8719	if (!CurInit.get()) return ExprError();
8720	break;
8721	}
8722
8723	case SK_ConstructorInitialization:
8724	case SK_ConstructorInitializationFromList:
8725	case SK_StdInitializerListConstructorCall:
8726	case SK_ZeroInitialization:
8727	case SK_ParenthesizedListInit:
8728	break;
8729	}
8730
8731	// Promote from an unevaluated context to an unevaluated list context in
8732	// C++11 list-initialization; we need to instantiate entities usable in
8733	// constant expressions here in order to perform narrowing checks =(
8734	EnterExpressionEvaluationContext Evaluated(
8735	S, EnterExpressionEvaluationContext::InitList,
8736	CurInit.get() && isa<InitListExpr>(Val: CurInit.get()));
8737
8738	// C++ [class.abstract]p2:
8739	// no objects of an abstract class can be created except as subobjects
8740	// of a class derived from it
8741	auto checkAbstractType = [&](QualType T) -> bool {
8742	if (Entity.getKind() == InitializedEntity::EK_Base ||
8743	Entity.getKind() == InitializedEntity::EK_Delegating)
8744	return false;
8745	return S.RequireNonAbstractType(Kind.getLocation(), T,
8746	diag::err_allocation_of_abstract_type);
8747	};
8748
8749	// Walk through the computed steps for the initialization sequence,
8750	// performing the specified conversions along the way.
8751	bool ConstructorInitRequiresZeroInit = false;
8752	for (step_iterator Step = step_begin(), StepEnd = step_end();
8753	Step != StepEnd; ++Step) {
8754	if (CurInit.isInvalid())
8755	return ExprError();
8756
8757	QualType SourceType = CurInit.get() ? CurInit.get()->getType() : QualType();
8758
8759	switch (Step->Kind) {
8760	case SK_ResolveAddressOfOverloadedFunction:
8761	// Overload resolution determined which function invoke; update the
8762	// initializer to reflect that choice.
8763	S.CheckAddressOfMemberAccess(OvlExpr: CurInit.get(), FoundDecl: Step->Function.FoundDecl);
8764	if (S.DiagnoseUseOfDecl(D: Step->Function.FoundDecl, Locs: Kind.getLocation()))
8765	return ExprError();
8766	CurInit = S.FixOverloadedFunctionReference(CurInit,
8767	FoundDecl: Step->Function.FoundDecl,
8768	Fn: Step->Function.Function);
8769	// We might get back another placeholder expression if we resolved to a
8770	// builtin.
8771	if (!CurInit.isInvalid())
8772	CurInit = S.CheckPlaceholderExpr(E: CurInit.get());
8773	break;
8774
8775	case SK_CastDerivedToBasePRValue:
8776	case SK_CastDerivedToBaseXValue:
8777	case SK_CastDerivedToBaseLValue: {
8778	// We have a derived-to-base cast that produces either an rvalue or an
8779	// lvalue. Perform that cast.
8780
8781	CXXCastPath BasePath;
8782
8783	// Casts to inaccessible base classes are allowed with C-style casts.
8784	bool IgnoreBaseAccess = Kind.isCStyleOrFunctionalCast();
8785	if (S.CheckDerivedToBaseConversion(
8786	SourceType, Step->Type, CurInit.get()->getBeginLoc(),
8787	CurInit.get()->getSourceRange(), &BasePath, IgnoreBaseAccess))
8788	return ExprError();
8789
8790	ExprValueKind VK =
8791	Step->Kind == SK_CastDerivedToBaseLValue
8792	? VK_LValue
8793	: (Step->Kind == SK_CastDerivedToBaseXValue ? VK_XValue
8794	: VK_PRValue);
8795	CurInit = ImplicitCastExpr::Create(Context: S.Context, T: Step->Type,
8796	Kind: CK_DerivedToBase, Operand: CurInit.get(),
8797	BasePath: &BasePath, Cat: VK, FPO: FPOptionsOverride());
8798	break;
8799	}
8800
8801	case SK_BindReference:
8802	// Reference binding does not have any corresponding ASTs.
8803
8804	// Check exception specifications
8805	if (S.CheckExceptionSpecCompatibility(From: CurInit.get(), ToType: DestType))
8806	return ExprError();
8807
8808	// We don't check for e.g. function pointers here, since address
8809	// availability checks should only occur when the function first decays
8810	// into a pointer or reference.
8811	if (CurInit.get()->getType()->isFunctionProtoType()) {
8812	if (auto *DRE = dyn_cast<DeclRefExpr>(Val: CurInit.get()->IgnoreParens())) {
8813	if (auto *FD = dyn_cast<FunctionDecl>(Val: DRE->getDecl())) {
8814	if (!S.checkAddressOfFunctionIsAvailable(Function: FD, /*Complain=*/true,
8815	Loc: DRE->getBeginLoc()))
8816	return ExprError();
8817	}
8818	}
8819	}
8820
8821	CheckForNullPointerDereference(S, E: CurInit.get());
8822	break;
8823
8824	case SK_BindReferenceToTemporary: {
8825	// Make sure the "temporary" is actually an rvalue.
8826	assert(CurInit.get()->isPRValue() && "not a temporary");
8827
8828	// Check exception specifications
8829	if (S.CheckExceptionSpecCompatibility(From: CurInit.get(), ToType: DestType))
8830	return ExprError();
8831
8832	QualType MTETy = Step->Type;
8833
8834	// When this is an incomplete array type (such as when this is
8835	// initializing an array of unknown bounds from an init list), use THAT
8836	// type instead so that we propagate the array bounds.
8837	if (MTETy->isIncompleteArrayType() &&
8838	!CurInit.get()->getType()->isIncompleteArrayType() &&
8839	S.Context.hasSameType(
8840	T1: MTETy->getPointeeOrArrayElementType(),
8841	T2: CurInit.get()->getType()->getPointeeOrArrayElementType()))
8842	MTETy = CurInit.get()->getType();
8843
8844	// Materialize the temporary into memory.
8845	MaterializeTemporaryExpr *MTE = S.CreateMaterializeTemporaryExpr(
8846	T: MTETy, Temporary: CurInit.get(), BoundToLvalueReference: Entity.getType()->isLValueReferenceType());
8847	CurInit = MTE;
8848
8849	// If we're extending this temporary to automatic storage duration -- we
8850	// need to register its cleanup during the full-expression's cleanups.
8851	if (MTE->getStorageDuration() == SD_Automatic &&
8852	MTE->getType().isDestructedType())
8853	S.Cleanup.setExprNeedsCleanups(true);
8854	break;
8855	}
8856
8857	case SK_FinalCopy:
8858	if (checkAbstractType(Step->Type))
8859	return ExprError();
8860
8861	// If the overall initialization is initializing a temporary, we already
8862	// bound our argument if it was necessary to do so. If not (if we're
8863	// ultimately initializing a non-temporary), our argument needs to be
8864	// bound since it's initializing a function parameter.
8865	// FIXME: This is a mess. Rationalize temporary destruction.
8866	if (!shouldBindAsTemporary(Entity))
8867	CurInit = S.MaybeBindToTemporary(E: CurInit.get());
8868	CurInit = CopyObject(S, Step->Type, Entity, CurInit,
8869	/*IsExtraneousCopy=*/false);
8870	break;
8871
8872	case SK_ExtraneousCopyToTemporary:
8873	CurInit = CopyObject(S, Step->Type, Entity, CurInit,
8874	/*IsExtraneousCopy=*/true);
8875	break;
8876
8877	case SK_UserConversion: {
8878	// We have a user-defined conversion that invokes either a constructor
8879	// or a conversion function.
8880	CastKind CastKind;
8881	FunctionDecl *Fn = Step->Function.Function;
8882	DeclAccessPair FoundFn = Step->Function.FoundDecl;
8883	bool HadMultipleCandidates = Step->Function.HadMultipleCandidates;
8884	bool CreatedObject = false;
8885	if (CXXConstructorDecl *Constructor = dyn_cast<CXXConstructorDecl>(Val: Fn)) {
8886	// Build a call to the selected constructor.
8887	SmallVector<Expr*, 8> ConstructorArgs;
8888	SourceLocation Loc = CurInit.get()->getBeginLoc();
8889
8890	// Determine the arguments required to actually perform the constructor
8891	// call.
8892	Expr *Arg = CurInit.get();
8893	if (S.CompleteConstructorCall(Constructor, DeclInitType: Step->Type,
8894	ArgsPtr: MultiExprArg(&Arg, 1), Loc,
8895	ConvertedArgs&: ConstructorArgs))
8896	return ExprError();
8897
8898	// Build an expression that constructs a temporary.
8899	CurInit = S.BuildCXXConstructExpr(
8900	Loc, Step->Type, FoundFn, Constructor, ConstructorArgs,
8901	HadMultipleCandidates,
8902	/*ListInit*/ false,
8903	/*StdInitListInit*/ false,
8904	/*ZeroInit*/ false, CXXConstructionKind::Complete, SourceRange());
8905	if (CurInit.isInvalid())
8906	return ExprError();
8907
8908	S.CheckConstructorAccess(Loc: Kind.getLocation(), D: Constructor, FoundDecl: FoundFn,
8909	Entity);
8910	if (S.DiagnoseUseOfDecl(D: FoundFn, Locs: Kind.getLocation()))
8911	return ExprError();
8912
8913	CastKind = CK_ConstructorConversion;
8914	CreatedObject = true;
8915	} else {
8916	// Build a call to the conversion function.
8917	CXXConversionDecl *Conversion = cast<CXXConversionDecl>(Val: Fn);
8918	S.CheckMemberOperatorAccess(Loc: Kind.getLocation(), ObjectExpr: CurInit.get(), ArgExpr: nullptr,
8919	FoundDecl: FoundFn);
8920	if (S.DiagnoseUseOfDecl(D: FoundFn, Locs: Kind.getLocation()))
8921	return ExprError();
8922
8923	CurInit = S.BuildCXXMemberCallExpr(Exp: CurInit.get(), FoundDecl: FoundFn, Method: Conversion,
8924	HadMultipleCandidates);
8925	if (CurInit.isInvalid())
8926	return ExprError();
8927
8928	CastKind = CK_UserDefinedConversion;
8929	CreatedObject = Conversion->getReturnType()->isRecordType();
8930	}
8931
8932	if (CreatedObject && checkAbstractType(CurInit.get()->getType()))
8933	return ExprError();
8934
8935	CurInit = ImplicitCastExpr::Create(
8936	Context: S.Context, T: CurInit.get()->getType(), Kind: CastKind, Operand: CurInit.get(), BasePath: nullptr,
8937	Cat: CurInit.get()->getValueKind(), FPO: S.CurFPFeatureOverrides());
8938
8939	if (shouldBindAsTemporary(Entity))
8940	// The overall entity is temporary, so this expression should be
8941	// destroyed at the end of its full-expression.
8942	CurInit = S.MaybeBindToTemporary(E: CurInit.getAs<Expr>());
8943	else if (CreatedObject && shouldDestroyEntity(Entity)) {
8944	// The object outlasts the full-expression, but we need to prepare for
8945	// a destructor being run on it.
8946	// FIXME: It makes no sense to do this here. This should happen
8947	// regardless of how we initialized the entity.
8948	QualType T = CurInit.get()->getType();
8949	if (const RecordType *Record = T->getAs<RecordType>()) {
8950	CXXDestructorDecl *Destructor
8951	= S.LookupDestructor(Class: cast<CXXRecordDecl>(Val: Record->getDecl()));
8952	S.CheckDestructorAccess(CurInit.get()->getBeginLoc(), Destructor,
8953	S.PDiag(diag::err_access_dtor_temp) << T);
8954	S.MarkFunctionReferenced(Loc: CurInit.get()->getBeginLoc(), Func: Destructor);
8955	if (S.DiagnoseUseOfDecl(D: Destructor, Locs: CurInit.get()->getBeginLoc()))
8956	return ExprError();
8957	}
8958	}
8959	break;
8960	}
8961
8962	case SK_QualificationConversionLValue:
8963	case SK_QualificationConversionXValue:
8964	case SK_QualificationConversionPRValue: {
8965	// Perform a qualification conversion; these can never go wrong.
8966	ExprValueKind VK =
8967	Step->Kind == SK_QualificationConversionLValue
8968	? VK_LValue
8969	: (Step->Kind == SK_QualificationConversionXValue ? VK_XValue
8970	: VK_PRValue);
8971	CurInit = S.PerformQualificationConversion(E: CurInit.get(), Ty: Step->Type, VK);
8972	break;
8973	}
8974
8975	case SK_FunctionReferenceConversion:
8976	assert(CurInit.get()->isLValue() &&
8977	"function reference should be lvalue");
8978	CurInit =
8979	S.ImpCastExprToType(E: CurInit.get(), Type: Step->Type, CK: CK_NoOp, VK: VK_LValue);
8980	break;
8981
8982	case SK_AtomicConversion: {
8983	assert(CurInit.get()->isPRValue() && "cannot convert glvalue to atomic");
8984	CurInit = S.ImpCastExprToType(E: CurInit.get(), Type: Step->Type,
8985	CK: CK_NonAtomicToAtomic, VK: VK_PRValue);
8986	break;
8987	}
8988
8989	case SK_ConversionSequence:
8990	case SK_ConversionSequenceNoNarrowing: {
8991	if (const auto *FromPtrType =
8992	CurInit.get()->getType()->getAs<PointerType>()) {
8993	if (const auto *ToPtrType = Step->Type->getAs<PointerType>()) {
8994	if (FromPtrType->getPointeeType()->hasAttr(attr::NoDeref) &&
8995	!ToPtrType->getPointeeType()->hasAttr(attr::NoDeref)) {
8996	// Do not check static casts here because they are checked earlier
8997	// in Sema::ActOnCXXNamedCast()
8998	if (!Kind.isStaticCast()) {
8999	S.Diag(CurInit.get()->getExprLoc(),
9000	diag::warn_noderef_to_dereferenceable_pointer)
9001	<< CurInit.get()->getSourceRange();
9002	}
9003	}
9004	}
9005	}
9006
9007	Sema::CheckedConversionKind CCK
9008	= Kind.isCStyleCast()? Sema::CCK_CStyleCast
9009	: Kind.isFunctionalCast()? Sema::CCK_FunctionalCast
9010	: Kind.isExplicitCast()? Sema::CCK_OtherCast
9011	: Sema::CCK_ImplicitConversion;
9012	ExprResult CurInitExprRes =
9013	S.PerformImplicitConversion(CurInit.get(), Step->Type, *Step->ICS,
9014	getAssignmentAction(Entity), CCK);
9015	if (CurInitExprRes.isInvalid())
9016	return ExprError();
9017
9018	S.DiscardMisalignedMemberAddress(T: Step->Type.getTypePtr(), E: CurInit.get());
9019
9020	CurInit = CurInitExprRes;
9021
9022	if (Step->Kind == SK_ConversionSequenceNoNarrowing &&
9023	S.getLangOpts().CPlusPlus)
9024	DiagnoseNarrowingInInitList(S, ICS: *Step->ICS, PreNarrowingType: SourceType, EntityType: Entity.getType(),
9025	PostInit: CurInit.get());
9026
9027	break;
9028	}
9029
9030	case SK_ListInitialization: {
9031	if (checkAbstractType(Step->Type))
9032	return ExprError();
9033
9034	InitListExpr *InitList = cast<InitListExpr>(Val: CurInit.get());
9035	// If we're not initializing the top-level entity, we need to create an
9036	// InitializeTemporary entity for our target type.
9037	QualType Ty = Step->Type;
9038	bool IsTemporary = !S.Context.hasSameType(T1: Entity.getType(), T2: Ty);
9039	InitializedEntity TempEntity = InitializedEntity::InitializeTemporary(Type: Ty);
9040	InitializedEntity InitEntity = IsTemporary ? TempEntity : Entity;
9041	InitListChecker PerformInitList(S, InitEntity,
9042	InitList, Ty, /*VerifyOnly=*/false,
9043	/*TreatUnavailableAsInvalid=*/false);
9044	if (PerformInitList.HadError())
9045	return ExprError();
9046
9047	// Hack: We must update *ResultType if available in order to set the
9048	// bounds of arrays, e.g. in 'int ar[] = {1, 2, 3};'.
9049	// Worst case: 'const int (&arref)[] = {1, 2, 3};'.
9050	if (ResultType &&
9051	ResultType->getNonReferenceType()->isIncompleteArrayType()) {
9052	if ((*ResultType)->isRValueReferenceType())
9053	Ty = S.Context.getRValueReferenceType(T: Ty);
9054	else if ((*ResultType)->isLValueReferenceType())
9055	Ty = S.Context.getLValueReferenceType(T: Ty,
9056	SpelledAsLValue: (*ResultType)->castAs<LValueReferenceType>()->isSpelledAsLValue());
9057	*ResultType = Ty;
9058	}
9059
9060	InitListExpr *StructuredInitList =
9061	PerformInitList.getFullyStructuredList();
9062	CurInit.get();
9063	CurInit = shouldBindAsTemporary(Entity: InitEntity)
9064	? S.MaybeBindToTemporary(StructuredInitList)
9065	: StructuredInitList;
9066	break;
9067	}
9068
9069	case SK_ConstructorInitializationFromList: {
9070	if (checkAbstractType(Step->Type))
9071	return ExprError();
9072
9073	// When an initializer list is passed for a parameter of type "reference
9074	// to object", we don't get an EK_Temporary entity, but instead an
9075	// EK_Parameter entity with reference type.
9076	// FIXME: This is a hack. What we really should do is create a user
9077	// conversion step for this case, but this makes it considerably more
9078	// complicated. For now, this will do.
9079	InitializedEntity TempEntity = InitializedEntity::InitializeTemporary(
9080	Type: Entity.getType().getNonReferenceType());
9081	bool UseTemporary = Entity.getType()->isReferenceType();
9082	assert(Args.size() == 1 && "expected a single argument for list init");
9083	InitListExpr *InitList = cast<InitListExpr>(Val: Args[0]);
9084	S.Diag(InitList->getExprLoc(), diag::warn_cxx98_compat_ctor_list_init)
9085	<< InitList->getSourceRange();
9086	MultiExprArg Arg(InitList->getInits(), InitList->getNumInits());
9087	CurInit = PerformConstructorInitialization(S, Entity: UseTemporary ? TempEntity :
9088	Entity,
9089	Kind, Args: Arg, Step: *Step,
9090	ConstructorInitRequiresZeroInit,
9091	/*IsListInitialization*/true,
9092	/*IsStdInitListInit*/IsStdInitListInitialization: false,
9093	LBraceLoc: InitList->getLBraceLoc(),
9094	RBraceLoc: InitList->getRBraceLoc());
9095	break;
9096	}
9097
9098	case SK_UnwrapInitList:
9099	CurInit = cast<InitListExpr>(Val: CurInit.get())->getInit(Init: 0);
9100	break;
9101
9102	case SK_RewrapInitList: {
9103	Expr *E = CurInit.get();
9104	InitListExpr *Syntactic = Step->WrappingSyntacticList;
9105	InitListExpr *ILE = new (S.Context) InitListExpr(S.Context,
9106	Syntactic->getLBraceLoc(), E, Syntactic->getRBraceLoc());
9107	ILE->setSyntacticForm(Syntactic);
9108	ILE->setType(E->getType());
9109	ILE->setValueKind(E->getValueKind());
9110	CurInit = ILE;
9111	break;
9112	}
9113
9114	case SK_ConstructorInitialization:
9115	case SK_StdInitializerListConstructorCall: {
9116	if (checkAbstractType(Step->Type))
9117	return ExprError();
9118
9119	// When an initializer list is passed for a parameter of type "reference
9120	// to object", we don't get an EK_Temporary entity, but instead an
9121	// EK_Parameter entity with reference type.
9122	// FIXME: This is a hack. What we really should do is create a user
9123	// conversion step for this case, but this makes it considerably more
9124	// complicated. For now, this will do.
9125	InitializedEntity TempEntity = InitializedEntity::InitializeTemporary(
9126	Type: Entity.getType().getNonReferenceType());
9127	bool UseTemporary = Entity.getType()->isReferenceType();
9128	bool IsStdInitListInit =
9129	Step->Kind == SK_StdInitializerListConstructorCall;
9130	Expr *Source = CurInit.get();
9131	SourceRange Range = Kind.hasParenOrBraceRange()
9132	? Kind.getParenOrBraceRange()
9133	: SourceRange();
9134	CurInit = PerformConstructorInitialization(
9135	S, Entity: UseTemporary ? TempEntity : Entity, Kind,
9136	Args: Source ? MultiExprArg(Source) : Args, Step: *Step,
9137	ConstructorInitRequiresZeroInit,
9138	/*IsListInitialization*/ IsStdInitListInit,
9139	/*IsStdInitListInitialization*/ IsStdInitListInit,
9140	/*LBraceLoc*/ Range.getBegin(),
9141	/*RBraceLoc*/ Range.getEnd());
9142	break;
9143	}
9144
9145	case SK_ZeroInitialization: {
9146	step_iterator NextStep = Step;
9147	++NextStep;
9148	if (NextStep != StepEnd &&
9149	(NextStep->Kind == SK_ConstructorInitialization ||
9150	NextStep->Kind == SK_ConstructorInitializationFromList)) {
9151	// The need for zero-initialization is recorded directly into
9152	// the call to the object's constructor within the next step.
9153	ConstructorInitRequiresZeroInit = true;
9154	} else if (Kind.getKind() == InitializationKind::IK_Value &&
9155	S.getLangOpts().CPlusPlus &&
9156	!Kind.isImplicitValueInit()) {
9157	TypeSourceInfo *TSInfo = Entity.getTypeSourceInfo();
9158	if (!TSInfo)
9159	TSInfo = S.Context.getTrivialTypeSourceInfo(T: Step->Type,
9160	Loc: Kind.getRange().getBegin());
9161
9162	CurInit = new (S.Context) CXXScalarValueInitExpr(
9163	Entity.getType().getNonLValueExprType(Context: S.Context), TSInfo,
9164	Kind.getRange().getEnd());
9165	} else {
9166	CurInit = new (S.Context) ImplicitValueInitExpr(Step->Type);
9167	}
9168	break;
9169	}
9170
9171	case SK_CAssignment: {
9172	QualType SourceType = CurInit.get()->getType();
9173
9174	// Save off the initial CurInit in case we need to emit a diagnostic
9175	ExprResult InitialCurInit = CurInit;
9176	ExprResult Result = CurInit;
9177	Sema::AssignConvertType ConvTy =
9178	S.CheckSingleAssignmentConstraints(LHSType: Step->Type, RHS&: Result, Diagnose: true,
9179	DiagnoseCFAudited: Entity.getKind() == InitializedEntity::EK_Parameter_CF_Audited);
9180	if (Result.isInvalid())
9181	return ExprError();
9182	CurInit = Result;
9183
9184	// If this is a call, allow conversion to a transparent union.
9185	ExprResult CurInitExprRes = CurInit;
9186	if (ConvTy != Sema::Compatible &&
9187	Entity.isParameterKind() &&
9188	S.CheckTransparentUnionArgumentConstraints(ArgType: Step->Type, RHS&: CurInitExprRes)
9189	== Sema::Compatible)
9190	ConvTy = Sema::Compatible;
9191	if (CurInitExprRes.isInvalid())
9192	return ExprError();
9193	CurInit = CurInitExprRes;
9194
9195	bool Complained;
9196	if (S.DiagnoseAssignmentResult(ConvTy, Loc: Kind.getLocation(),
9197	DstType: Step->Type, SrcType: SourceType,
9198	SrcExpr: InitialCurInit.get(),
9199	Action: getAssignmentAction(Entity, Diagnose: true),
9200	Complained: &Complained)) {
9201	PrintInitLocationNote(S, Entity);
9202	return ExprError();
9203	} else if (Complained)
9204	PrintInitLocationNote(S, Entity);
9205	break;
9206	}
9207
9208	case SK_StringInit: {
9209	QualType Ty = Step->Type;
9210	bool UpdateType = ResultType && Entity.getType()->isIncompleteArrayType();
9211	CheckStringInit(Str: CurInit.get(), DeclT&: UpdateType ? *ResultType : Ty,
9212	AT: S.Context.getAsArrayType(T: Ty), S);
9213	break;
9214	}
9215
9216	case SK_ObjCObjectConversion:
9217	CurInit = S.ImpCastExprToType(E: CurInit.get(), Type: Step->Type,
9218	CK: CK_ObjCObjectLValueCast,
9219	VK: CurInit.get()->getValueKind());
9220	break;
9221
9222	case SK_ArrayLoopIndex: {
9223	Expr *Cur = CurInit.get();
9224	Expr *BaseExpr = new (S.Context)
9225	OpaqueValueExpr(Cur->getExprLoc(), Cur->getType(),
9226	Cur->getValueKind(), Cur->getObjectKind(), Cur);
9227	Expr *IndexExpr =
9228	new (S.Context) ArrayInitIndexExpr(S.Context.getSizeType());
9229	CurInit = S.CreateBuiltinArraySubscriptExpr(
9230	Base: BaseExpr, LLoc: Kind.getLocation(), Idx: IndexExpr, RLoc: Kind.getLocation());
9231	ArrayLoopCommonExprs.push_back(Elt: BaseExpr);
9232	break;
9233	}
9234
9235	case SK_ArrayLoopInit: {
9236	assert(!ArrayLoopCommonExprs.empty() &&
9237	"mismatched SK_ArrayLoopIndex and SK_ArrayLoopInit");
9238	Expr *Common = ArrayLoopCommonExprs.pop_back_val();
9239	CurInit = new (S.Context) ArrayInitLoopExpr(Step->Type, Common,
9240	CurInit.get());
9241	break;
9242	}
9243
9244	case SK_GNUArrayInit:
9245	// Okay: we checked everything before creating this step. Note that
9246	// this is a GNU extension.
9247	S.Diag(Kind.getLocation(), diag::ext_array_init_copy)
9248	<< Step->Type << CurInit.get()->getType()
9249	<< CurInit.get()->getSourceRange();
9250	updateGNUCompoundLiteralRValue(E: CurInit.get());
9251	[[fallthrough]];
9252	case SK_ArrayInit:
9253	// If the destination type is an incomplete array type, update the
9254	// type accordingly.
9255	if (ResultType) {
9256	if (const IncompleteArrayType *IncompleteDest
9257	= S.Context.getAsIncompleteArrayType(T: Step->Type)) {
9258	if (const ConstantArrayType *ConstantSource
9259	= S.Context.getAsConstantArrayType(T: CurInit.get()->getType())) {
9260	*ResultType = S.Context.getConstantArrayType(
9261	EltTy: IncompleteDest->getElementType(), ArySize: ConstantSource->getSize(),
9262	SizeExpr: ConstantSource->getSizeExpr(), ASM: ArraySizeModifier::Normal, IndexTypeQuals: 0);
9263	}
9264	}
9265	}
9266	break;
9267
9268	case SK_ParenthesizedArrayInit:
9269	// Okay: we checked everything before creating this step. Note that
9270	// this is a GNU extension.
9271	S.Diag(Kind.getLocation(), diag::ext_array_init_parens)
9272	<< CurInit.get()->getSourceRange();
9273	break;
9274
9275	case SK_PassByIndirectCopyRestore:
9276	case SK_PassByIndirectRestore:
9277	checkIndirectCopyRestoreSource(S, src: CurInit.get());
9278	CurInit = new (S.Context) ObjCIndirectCopyRestoreExpr(
9279	CurInit.get(), Step->Type,
9280	Step->Kind == SK_PassByIndirectCopyRestore);
9281	break;
9282
9283	case SK_ProduceObjCObject:
9284	CurInit = ImplicitCastExpr::Create(
9285	Context: S.Context, T: Step->Type, Kind: CK_ARCProduceObject, Operand: CurInit.get(), BasePath: nullptr,
9286	Cat: VK_PRValue, FPO: FPOptionsOverride());
9287	break;
9288
9289	case SK_StdInitializerList: {
9290	S.Diag(CurInit.get()->getExprLoc(),
9291	diag::warn_cxx98_compat_initializer_list_init)
9292	<< CurInit.get()->getSourceRange();
9293
9294	// Materialize the temporary into memory.
9295	MaterializeTemporaryExpr *MTE = S.CreateMaterializeTemporaryExpr(
9296	T: CurInit.get()->getType(), Temporary: CurInit.get(),
9297	/*BoundToLvalueReference=*/false);
9298
9299	// Wrap it in a construction of a std::initializer_list<T>.
9300	CurInit = new (S.Context) CXXStdInitializerListExpr(Step->Type, MTE);
9301
9302	// Bind the result, in case the library has given initializer_list a
9303	// non-trivial destructor.
9304	if (shouldBindAsTemporary(Entity))
9305	CurInit = S.MaybeBindToTemporary(E: CurInit.get());
9306	break;
9307	}
9308
9309	case SK_OCLSamplerInit: {
9310	// Sampler initialization have 5 cases:
9311	// 1. function argument passing
9312	// 1a. argument is a file-scope variable
9313	// 1b. argument is a function-scope variable
9314	// 1c. argument is one of caller function's parameters
9315	// 2. variable initialization
9316	// 2a. initializing a file-scope variable
9317	// 2b. initializing a function-scope variable
9318	//
9319	// For file-scope variables, since they cannot be initialized by function
9320	// call of __translate_sampler_initializer in LLVM IR, their references
9321	// need to be replaced by a cast from their literal initializers to
9322	// sampler type. Since sampler variables can only be used in function
9323	// calls as arguments, we only need to replace them when handling the
9324	// argument passing.
9325	assert(Step->Type->isSamplerT() &&
9326	"Sampler initialization on non-sampler type.");
9327	Expr *Init = CurInit.get()->IgnoreParens();
9328	QualType SourceType = Init->getType();
9329	// Case 1
9330	if (Entity.isParameterKind()) {
9331	if (!SourceType->isSamplerT() && !SourceType->isIntegerType()) {
9332	S.Diag(Kind.getLocation(), diag::err_sampler_argument_required)
9333	<< SourceType;
9334	break;
9335	} else if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Val: Init)) {
9336	auto Var = cast<VarDecl>(Val: DRE->getDecl());
9337	// Case 1b and 1c
9338	// No cast from integer to sampler is needed.
9339	if (!Var->hasGlobalStorage()) {
9340	CurInit = ImplicitCastExpr::Create(
9341	Context: S.Context, T: Step->Type, Kind: CK_LValueToRValue, Operand: Init,
9342	/*BasePath=*/nullptr, Cat: VK_PRValue, FPO: FPOptionsOverride());
9343	break;
9344	}
9345	// Case 1a
9346	// For function call with a file-scope sampler variable as argument,
9347	// get the integer literal.
9348	// Do not diagnose if the file-scope variable does not have initializer
9349	// since this has already been diagnosed when parsing the variable
9350	// declaration.
9351	if (!Var->getInit() || !isa<ImplicitCastExpr>(Val: Var->getInit()))
9352	break;
9353	Init = cast<ImplicitCastExpr>(Val: const_cast<Expr*>(
9354	Var->getInit()))->getSubExpr();
9355	SourceType = Init->getType();
9356	}
9357	} else {
9358	// Case 2
9359	// Check initializer is 32 bit integer constant.
9360	// If the initializer is taken from global variable, do not diagnose since
9361	// this has already been done when parsing the variable declaration.
9362	if (!Init->isConstantInitializer(Ctx&: S.Context, ForRef: false))
9363	break;
9364
9365	if (!SourceType->isIntegerType() ||
9366	32 != S.Context.getIntWidth(T: SourceType)) {
9367	S.Diag(Kind.getLocation(), diag::err_sampler_initializer_not_integer)
9368	<< SourceType;
9369	break;
9370	}
9371
9372	Expr::EvalResult EVResult;
9373	Init->EvaluateAsInt(Result&: EVResult, Ctx: S.Context);
9374	llvm::APSInt Result = EVResult.Val.getInt();
9375	const uint64_t SamplerValue = Result.getLimitedValue();
9376	// 32-bit value of sampler's initializer is interpreted as
9377	// bit-field with the following structure:
9378	// |unspecified|Filter|Addressing Mode| Normalized Coords|
9379	// |31 6|5 4|3 1| 0|
9380	// This structure corresponds to enum values of sampler properties
9381	// defined in SPIR spec v1.2 and also opencl-c.h
9382	unsigned AddressingMode = (0x0E & SamplerValue) >> 1;
9383	unsigned FilterMode = (0x30 & SamplerValue) >> 4;
9384	if (FilterMode != 1 && FilterMode != 2 &&
9385	!S.getOpenCLOptions().isAvailableOption(
9386	"cl_intel_device_side_avc_motion_estimation", S.getLangOpts()))
9387	S.Diag(Kind.getLocation(),
9388	diag::warn_sampler_initializer_invalid_bits)
9389	<< "Filter Mode";
9390	if (AddressingMode > 4)
9391	S.Diag(Kind.getLocation(),
9392	diag::warn_sampler_initializer_invalid_bits)
9393	<< "Addressing Mode";
9394	}
9395
9396	// Cases 1a, 2a and 2b
9397	// Insert cast from integer to sampler.
9398	CurInit = S.ImpCastExprToType(E: Init, Type: S.Context.OCLSamplerTy,
9399	CK: CK_IntToOCLSampler);
9400	break;
9401	}
9402	case SK_OCLZeroOpaqueType: {
9403	assert((Step->Type->isEventT() || Step->Type->isQueueT() ||
9404	Step->Type->isOCLIntelSubgroupAVCType()) &&
9405	"Wrong type for initialization of OpenCL opaque type.");
9406
9407	CurInit = S.ImpCastExprToType(E: CurInit.get(), Type: Step->Type,
9408	CK: CK_ZeroToOCLOpaqueType,
9409	VK: CurInit.get()->getValueKind());
9410	break;
9411	}
9412	case SK_ParenthesizedListInit: {
9413	CurInit = nullptr;
9414	TryOrBuildParenListInitialization(S, Entity, Kind, Args, Sequence&: *this,
9415	/*VerifyOnly=*/false, Result: &CurInit);
9416	if (CurInit.get() && ResultType)
9417	*ResultType = CurInit.get()->getType();
9418	if (shouldBindAsTemporary(Entity))
9419	CurInit = S.MaybeBindToTemporary(E: CurInit.get());
9420	break;
9421	}
9422	}
9423	}
9424
9425	Expr *Init = CurInit.get();
9426	if (!Init)
9427	return ExprError();
9428
9429	// Check whether the initializer has a shorter lifetime than the initialized
9430	// entity, and if not, either lifetime-extend or warn as appropriate.
9431	S.checkInitializerLifetime(Entity, Init);
9432
9433	// Diagnose non-fatal problems with the completed initialization.
9434	if (InitializedEntity::EntityKind EK = Entity.getKind();
9435	(EK == InitializedEntity::EK_Member ||
9436	EK == InitializedEntity::EK_ParenAggInitMember) &&
9437	cast<FieldDecl>(Val: Entity.getDecl())->isBitField())
9438	S.CheckBitFieldInitialization(InitLoc: Kind.getLocation(),
9439	Field: cast<FieldDecl>(Val: Entity.getDecl()), Init);
9440
9441	// Check for std::move on construction.
9442	CheckMoveOnConstruction(S, InitExpr: Init,
9443	IsReturnStmt: Entity.getKind() == InitializedEntity::EK_Result);
9444
9445	return Init;
9446	}
9447
9448	/// Somewhere within T there is an uninitialized reference subobject.
9449	/// Dig it out and diagnose it.
9450	static bool DiagnoseUninitializedReference(Sema &S, SourceLocation Loc,
9451	QualType T) {
9452	if (T->isReferenceType()) {
9453	S.Diag(Loc, diag::err_reference_without_init)
9454	<< T.getNonReferenceType();
9455	return true;
9456	}
9457
9458	CXXRecordDecl *RD = T->getBaseElementTypeUnsafe()->getAsCXXRecordDecl();
9459	if (!RD || !RD->hasUninitializedReferenceMember())
9460	return false;
9461
9462	for (const auto *FI : RD->fields()) {
9463	if (FI->isUnnamedBitfield())
9464	continue;
9465
9466	if (DiagnoseUninitializedReference(S, FI->getLocation(), FI->getType())) {
9467	S.Diag(Loc, diag::note_value_initialization_here) << RD;
9468	return true;
9469	}
9470	}
9471
9472	for (const auto &BI : RD->bases()) {
9473	if (DiagnoseUninitializedReference(S, Loc: BI.getBeginLoc(), T: BI.getType())) {
9474	S.Diag(Loc, diag::note_value_initialization_here) << RD;
9475	return true;
9476	}
9477	}
9478
9479	return false;
9480	}
9481
9482
9483	//===----------------------------------------------------------------------===//
9484	// Diagnose initialization failures
9485	//===----------------------------------------------------------------------===//
9486
9487	/// Emit notes associated with an initialization that failed due to a
9488	/// "simple" conversion failure.
9489	static void emitBadConversionNotes(Sema &S, const InitializedEntity &entity,
9490	Expr *op) {
9491	QualType destType = entity.getType();
9492	if (destType.getNonReferenceType()->isObjCObjectPointerType() &&
9493	op->getType()->isObjCObjectPointerType()) {
9494
9495	// Emit a possible note about the conversion failing because the
9496	// operand is a message send with a related result type.
9497	S.EmitRelatedResultTypeNote(E: op);
9498
9499	// Emit a possible note about a return failing because we're
9500	// expecting a related result type.
9501	if (entity.getKind() == InitializedEntity::EK_Result)
9502	S.EmitRelatedResultTypeNoteForReturn(destType);
9503	}
9504	QualType fromType = op->getType();
9505	QualType fromPointeeType = fromType.getCanonicalType()->getPointeeType();
9506	QualType destPointeeType = destType.getCanonicalType()->getPointeeType();
9507	auto *fromDecl = fromType->getPointeeCXXRecordDecl();
9508	auto *destDecl = destType->getPointeeCXXRecordDecl();
9509	if (fromDecl && destDecl && fromDecl->getDeclKind() == Decl::CXXRecord &&
9510	destDecl->getDeclKind() == Decl::CXXRecord &&
9511	!fromDecl->isInvalidDecl() && !destDecl->isInvalidDecl() &&
9512	!fromDecl->hasDefinition() &&
9513	destPointeeType.getQualifiers().compatiblyIncludes(
9514	fromPointeeType.getQualifiers()))
9515	S.Diag(fromDecl->getLocation(), diag::note_forward_class_conversion)
9516	<< S.getASTContext().getTagDeclType(fromDecl)
9517	<< S.getASTContext().getTagDeclType(destDecl);
9518	}
9519
9520	static void diagnoseListInit(Sema &S, const InitializedEntity &Entity,
9521	InitListExpr *InitList) {
9522	QualType DestType = Entity.getType();
9523
9524	QualType E;
9525	if (S.getLangOpts().CPlusPlus11 && S.isStdInitializerList(Ty: DestType, Element: &E)) {
9526	QualType ArrayType = S.Context.getConstantArrayType(
9527	EltTy: E.withConst(),
9528	ArySize: llvm::APInt(S.Context.getTypeSize(T: S.Context.getSizeType()),
9529	InitList->getNumInits()),
9530	SizeExpr: nullptr, ASM: clang::ArraySizeModifier::Normal, IndexTypeQuals: 0);
9531	InitializedEntity HiddenArray =
9532	InitializedEntity::InitializeTemporary(Type: ArrayType);
9533	return diagnoseListInit(S, Entity: HiddenArray, InitList);
9534	}
9535
9536	if (DestType->isReferenceType()) {
9537	// A list-initialization failure for a reference means that we tried to
9538	// create a temporary of the inner type (per [dcl.init.list]p3.6) and the
9539	// inner initialization failed.
9540	QualType T = DestType->castAs<ReferenceType>()->getPointeeType();
9541	diagnoseListInit(S, Entity: InitializedEntity::InitializeTemporary(Type: T), InitList);
9542	SourceLocation Loc = InitList->getBeginLoc();
9543	if (auto *D = Entity.getDecl())
9544	Loc = D->getLocation();
9545	S.Diag(Loc, diag::note_in_reference_temporary_list_initializer) << T;
9546	return;
9547	}
9548
9549	InitListChecker DiagnoseInitList(S, Entity, InitList, DestType,
9550	/*VerifyOnly=*/false,
9551	/*TreatUnavailableAsInvalid=*/false);
9552	assert(DiagnoseInitList.HadError() &&
9553	"Inconsistent init list check result.");
9554	}
9555
9556	bool InitializationSequence::Diagnose(Sema &S,
9557	const InitializedEntity &Entity,
9558	const InitializationKind &Kind,
9559	ArrayRef<Expr *> Args) {
9560	if (!Failed())
9561	return false;
9562
9563	// When we want to diagnose only one element of a braced-init-list,
9564	// we need to factor it out.
9565	Expr *OnlyArg;
9566	if (Args.size() == 1) {
9567	auto *List = dyn_cast<InitListExpr>(Val: Args[0]);
9568	if (List && List->getNumInits() == 1)
9569	OnlyArg = List->getInit(Init: 0);
9570	else
9571	OnlyArg = Args[0];
9572	}
9573	else
9574	OnlyArg = nullptr;
9575
9576	QualType DestType = Entity.getType();
9577	switch (Failure) {
9578	case FK_TooManyInitsForReference:
9579	// FIXME: Customize for the initialized entity?
9580	if (Args.empty()) {
9581	// Dig out the reference subobject which is uninitialized and diagnose it.
9582	// If this is value-initialization, this could be nested some way within
9583	// the target type.
9584	assert(Kind.getKind() == InitializationKind::IK_Value ||
9585	DestType->isReferenceType());
9586	bool Diagnosed =
9587	DiagnoseUninitializedReference(S, Loc: Kind.getLocation(), T: DestType);
9588	assert(Diagnosed && "couldn't find uninitialized reference to diagnose");
9589	(void)Diagnosed;
9590	} else // FIXME: diagnostic below could be better!
9591	S.Diag(Kind.getLocation(), diag::err_reference_has_multiple_inits)
9592	<< SourceRange(Args.front()->getBeginLoc(), Args.back()->getEndLoc());
9593	break;
9594	case FK_ParenthesizedListInitForReference:
9595	S.Diag(Kind.getLocation(), diag::err_list_init_in_parens)
9596	<< 1 << Entity.getType() << Args[0]->getSourceRange();
9597	break;
9598
9599	case FK_ArrayNeedsInitList:
9600	S.Diag(Kind.getLocation(), diag::err_array_init_not_init_list) << 0;
9601	break;
9602	case FK_ArrayNeedsInitListOrStringLiteral:
9603	S.Diag(Kind.getLocation(), diag::err_array_init_not_init_list) << 1;
9604	break;
9605	case FK_ArrayNeedsInitListOrWideStringLiteral:
9606	S.Diag(Kind.getLocation(), diag::err_array_init_not_init_list) << 2;
9607	break;
9608	case FK_NarrowStringIntoWideCharArray:
9609	S.Diag(Kind.getLocation(), diag::err_array_init_narrow_string_into_wchar);
9610	break;
9611	case FK_WideStringIntoCharArray:
9612	S.Diag(Kind.getLocation(), diag::err_array_init_wide_string_into_char);
9613	break;
9614	case FK_IncompatWideStringIntoWideChar:
9615	S.Diag(Kind.getLocation(),
9616	diag::err_array_init_incompat_wide_string_into_wchar);
9617	break;
9618	case FK_PlainStringIntoUTF8Char:
9619	S.Diag(Kind.getLocation(),
9620	diag::err_array_init_plain_string_into_char8_t);
9621	S.Diag(Args.front()->getBeginLoc(),
9622	diag::note_array_init_plain_string_into_char8_t)
9623	<< FixItHint::CreateInsertion(Args.front()->getBeginLoc(), "u8");
9624	break;
9625	case FK_UTF8StringIntoPlainChar:
9626	S.Diag(Kind.getLocation(), diag::err_array_init_utf8_string_into_char)
9627	<< DestType->isSignedIntegerType() << S.getLangOpts().CPlusPlus20;
9628	break;
9629	case FK_ArrayTypeMismatch:
9630	case FK_NonConstantArrayInit:
9631	S.Diag(Kind.getLocation(),
9632	(Failure == FK_ArrayTypeMismatch
9633	? diag::err_array_init_different_type
9634	: diag::err_array_init_non_constant_array))
9635	<< DestType.getNonReferenceType()
9636	<< OnlyArg->getType()
9637	<< Args[0]->getSourceRange();
9638	break;
9639
9640	case FK_VariableLengthArrayHasInitializer:
9641	S.Diag(Kind.getLocation(), diag::err_variable_object_no_init)
9642	<< Args[0]->getSourceRange();
9643	break;
9644
9645	case FK_AddressOfOverloadFailed: {
9646	DeclAccessPair Found;
9647	S.ResolveAddressOfOverloadedFunction(AddressOfExpr: OnlyArg,
9648	TargetType: DestType.getNonReferenceType(),
9649	Complain: true,
9650	Found);
9651	break;
9652	}
9653
9654	case FK_AddressOfUnaddressableFunction: {
9655	auto *FD = cast<FunctionDecl>(Val: cast<DeclRefExpr>(Val: OnlyArg)->getDecl());
9656	S.checkAddressOfFunctionIsAvailable(Function: FD, /*Complain=*/true,
9657	Loc: OnlyArg->getBeginLoc());
9658	break;
9659	}
9660
9661	case FK_ReferenceInitOverloadFailed:
9662	case FK_UserConversionOverloadFailed:
9663	switch (FailedOverloadResult) {
9664	case OR_Ambiguous:
9665
9666	FailedCandidateSet.NoteCandidates(
9667	PartialDiagnosticAt(
9668	Kind.getLocation(),
9669	Failure == FK_UserConversionOverloadFailed
9670	? (S.PDiag(diag::err_typecheck_ambiguous_condition)
9671	<< OnlyArg->getType() << DestType
9672	<< Args[0]->getSourceRange())
9673	: (S.PDiag(diag::err_ref_init_ambiguous)
9674	<< DestType << OnlyArg->getType()
9675	<< Args[0]->getSourceRange())),
9676	S, OCD_AmbiguousCandidates, Args);
9677	break;
9678
9679	case OR_No_Viable_Function: {
9680	auto Cands = FailedCandidateSet.CompleteCandidates(S, OCD: OCD_AllCandidates, Args);
9681	if (!S.RequireCompleteType(Kind.getLocation(),
9682	DestType.getNonReferenceType(),
9683	diag::err_typecheck_nonviable_condition_incomplete,
9684	OnlyArg->getType(), Args[0]->getSourceRange()))
9685	S.Diag(Kind.getLocation(), diag::err_typecheck_nonviable_condition)
9686	<< (Entity.getKind() == InitializedEntity::EK_Result)
9687	<< OnlyArg->getType() << Args[0]->getSourceRange()
9688	<< DestType.getNonReferenceType();
9689
9690	FailedCandidateSet.NoteCandidates(S, Args, Cands);
9691	break;
9692	}
9693	case OR_Deleted: {
9694	S.Diag(Kind.getLocation(), diag::err_typecheck_deleted_function)
9695	<< OnlyArg->getType() << DestType.getNonReferenceType()
9696	<< Args[0]->getSourceRange();
9697	OverloadCandidateSet::iterator Best;
9698	OverloadingResult Ovl
9699	= FailedCandidateSet.BestViableFunction(S, Loc: Kind.getLocation(), Best);
9700	if (Ovl == OR_Deleted) {
9701	S.NoteDeletedFunction(FD: Best->Function);
9702	} else {
9703	llvm_unreachable("Inconsistent overload resolution?");
9704	}
9705	break;
9706	}
9707
9708	case OR_Success:
9709	llvm_unreachable("Conversion did not fail!");
9710	}
9711	break;
9712
9713	case FK_NonConstLValueReferenceBindingToTemporary:
9714	if (isa<InitListExpr>(Val: Args[0])) {
9715	S.Diag(Kind.getLocation(),
9716	diag::err_lvalue_reference_bind_to_initlist)
9717	<< DestType.getNonReferenceType().isVolatileQualified()
9718	<< DestType.getNonReferenceType()
9719	<< Args[0]->getSourceRange();
9720	break;
9721	}
9722	[[fallthrough]];
9723
9724	case FK_NonConstLValueReferenceBindingToUnrelated:
9725	S.Diag(Kind.getLocation(),
9726	Failure == FK_NonConstLValueReferenceBindingToTemporary
9727	? diag::err_lvalue_reference_bind_to_temporary
9728	: diag::err_lvalue_reference_bind_to_unrelated)
9729	<< DestType.getNonReferenceType().isVolatileQualified()
9730	<< DestType.getNonReferenceType()
9731	<< OnlyArg->getType()
9732	<< Args[0]->getSourceRange();
9733	break;
9734
9735	case FK_NonConstLValueReferenceBindingToBitfield: {
9736	// We don't necessarily have an unambiguous source bit-field.
9737	FieldDecl *BitField = Args[0]->getSourceBitField();
9738	S.Diag(Kind.getLocation(), diag::err_reference_bind_to_bitfield)
9739	<< DestType.isVolatileQualified()
9740	<< (BitField ? BitField->getDeclName() : DeclarationName())
9741	<< (BitField != nullptr)
9742	<< Args[0]->getSourceRange();
9743	if (BitField)
9744	S.Diag(BitField->getLocation(), diag::note_bitfield_decl);
9745	break;
9746	}
9747
9748	case FK_NonConstLValueReferenceBindingToVectorElement:
9749	S.Diag(Kind.getLocation(), diag::err_reference_bind_to_vector_element)
9750	<< DestType.isVolatileQualified()
9751	<< Args[0]->getSourceRange();
9752	break;
9753
9754	case FK_NonConstLValueReferenceBindingToMatrixElement:
9755	S.Diag(Kind.getLocation(), diag::err_reference_bind_to_matrix_element)
9756	<< DestType.isVolatileQualified() << Args[0]->getSourceRange();
9757	break;
9758
9759	case FK_RValueReferenceBindingToLValue:
9760	S.Diag(Kind.getLocation(), diag::err_lvalue_to_rvalue_ref)
9761	<< DestType.getNonReferenceType() << OnlyArg->getType()
9762	<< Args[0]->getSourceRange();
9763	break;
9764
9765	case FK_ReferenceAddrspaceMismatchTemporary:
9766	S.Diag(Kind.getLocation(), diag::err_reference_bind_temporary_addrspace)
9767	<< DestType << Args[0]->getSourceRange();
9768	break;
9769
9770	case FK_ReferenceInitDropsQualifiers: {
9771	QualType SourceType = OnlyArg->getType();
9772	QualType NonRefType = DestType.getNonReferenceType();
9773	Qualifiers DroppedQualifiers =
9774	SourceType.getQualifiers() - NonRefType.getQualifiers();
9775
9776	if (!NonRefType.getQualifiers().isAddressSpaceSupersetOf(
9777	SourceType.getQualifiers()))
9778	S.Diag(Kind.getLocation(), diag::err_reference_bind_drops_quals)
9779	<< NonRefType << SourceType << 1 /*addr space*/
9780	<< Args[0]->getSourceRange();
9781	else if (DroppedQualifiers.hasQualifiers())
9782	S.Diag(Kind.getLocation(), diag::err_reference_bind_drops_quals)
9783	<< NonRefType << SourceType << 0 /*cv quals*/
9784	<< Qualifiers::fromCVRMask(DroppedQualifiers.getCVRQualifiers())
9785	<< DroppedQualifiers.getCVRQualifiers() << Args[0]->getSourceRange();
9786	else
9787	// FIXME: Consider decomposing the type and explaining which qualifiers
9788	// were dropped where, or on which level a 'const' is missing, etc.
9789	S.Diag(Kind.getLocation(), diag::err_reference_bind_drops_quals)
9790	<< NonRefType << SourceType << 2 /*incompatible quals*/
9791	<< Args[0]->getSourceRange();
9792	break;
9793	}
9794
9795	case FK_ReferenceInitFailed:
9796	S.Diag(Kind.getLocation(), diag::err_reference_bind_failed)
9797	<< DestType.getNonReferenceType()
9798	<< DestType.getNonReferenceType()->isIncompleteType()
9799	<< OnlyArg->isLValue()
9800	<< OnlyArg->getType()
9801	<< Args[0]->getSourceRange();
9802	emitBadConversionNotes(S, entity: Entity, op: Args[0]);
9803	break;
9804
9805	case FK_ConversionFailed: {
9806	QualType FromType = OnlyArg->getType();
9807	PartialDiagnostic PDiag = S.PDiag(diag::err_init_conversion_failed)
9808	<< (int)Entity.getKind()
9809	<< DestType
9810	<< OnlyArg->isLValue()
9811	<< FromType
9812	<< Args[0]->getSourceRange();
9813	S.HandleFunctionTypeMismatch(PDiag, FromType, ToType: DestType);
9814	S.Diag(Loc: Kind.getLocation(), PD: PDiag);
9815	emitBadConversionNotes(S, entity: Entity, op: Args[0]);
9816	break;
9817	}
9818
9819	case FK_ConversionFromPropertyFailed:
9820	// No-op. This error has already been reported.
9821	break;
9822
9823	case FK_TooManyInitsForScalar: {
9824	SourceRange R;
9825
9826	auto *InitList = dyn_cast<InitListExpr>(Val: Args[0]);
9827	if (InitList && InitList->getNumInits() >= 1) {
9828	R = SourceRange(InitList->getInit(Init: 0)->getEndLoc(), InitList->getEndLoc());
9829	} else {
9830	assert(Args.size() > 1 && "Expected multiple initializers!");
9831	R = SourceRange(Args.front()->getEndLoc(), Args.back()->getEndLoc());
9832	}
9833
9834	R.setBegin(S.getLocForEndOfToken(Loc: R.getBegin()));
9835	if (Kind.isCStyleOrFunctionalCast())
9836	S.Diag(Kind.getLocation(), diag::err_builtin_func_cast_more_than_one_arg)
9837	<< R;
9838	else
9839	S.Diag(Kind.getLocation(), diag::err_excess_initializers)
9840	<< /*scalar=*/2 << R;
9841	break;
9842	}
9843
9844	case FK_ParenthesizedListInitForScalar:
9845	S.Diag(Kind.getLocation(), diag::err_list_init_in_parens)
9846	<< 0 << Entity.getType() << Args[0]->getSourceRange();
9847	break;
9848
9849	case FK_ReferenceBindingToInitList:
9850	S.Diag(Kind.getLocation(), diag::err_reference_bind_init_list)
9851	<< DestType.getNonReferenceType() << Args[0]->getSourceRange();
9852	break;
9853
9854	case FK_InitListBadDestinationType:
9855	S.Diag(Kind.getLocation(), diag::err_init_list_bad_dest_type)
9856	<< (DestType->isRecordType()) << DestType << Args[0]->getSourceRange();
9857	break;
9858
9859	case FK_ListConstructorOverloadFailed:
9860	case FK_ConstructorOverloadFailed: {
9861	SourceRange ArgsRange;
9862	if (Args.size())
9863	ArgsRange =
9864	SourceRange(Args.front()->getBeginLoc(), Args.back()->getEndLoc());
9865
9866	if (Failure == FK_ListConstructorOverloadFailed) {
9867	assert(Args.size() == 1 &&
9868	"List construction from other than 1 argument.");
9869	InitListExpr *InitList = cast<InitListExpr>(Val: Args[0]);
9870	Args = MultiExprArg(InitList->getInits(), InitList->getNumInits());
9871	}
9872
9873	// FIXME: Using "DestType" for the entity we're printing is probably
9874	// bad.
9875	switch (FailedOverloadResult) {
9876	case OR_Ambiguous:
9877	FailedCandidateSet.NoteCandidates(
9878	PartialDiagnosticAt(Kind.getLocation(),
9879	S.PDiag(diag::err_ovl_ambiguous_init)
9880	<< DestType << ArgsRange),
9881	S, OCD_AmbiguousCandidates, Args);
9882	break;
9883
9884	case OR_No_Viable_Function:
9885	if (Kind.getKind() == InitializationKind::IK_Default &&
9886	(Entity.getKind() == InitializedEntity::EK_Base ||
9887	Entity.getKind() == InitializedEntity::EK_Member ||
9888	Entity.getKind() == InitializedEntity::EK_ParenAggInitMember) &&
9889	isa<CXXConstructorDecl>(Val: S.CurContext)) {
9890	// This is implicit default initialization of a member or
9891	// base within a constructor. If no viable function was
9892	// found, notify the user that they need to explicitly
9893	// initialize this base/member.
9894	CXXConstructorDecl *Constructor
9895	= cast<CXXConstructorDecl>(Val: S.CurContext);
9896	const CXXRecordDecl *InheritedFrom = nullptr;
9897	if (auto Inherited = Constructor->getInheritedConstructor())
9898	InheritedFrom = Inherited.getShadowDecl()->getNominatedBaseClass();
9899	if (Entity.getKind() == InitializedEntity::EK_Base) {
9900	S.Diag(Kind.getLocation(), diag::err_missing_default_ctor)
9901	<< (InheritedFrom ? 2 : Constructor->isImplicit() ? 1 : 0)
9902	<< S.Context.getTypeDeclType(Constructor->getParent())
9903	<< /*base=*/0
9904	<< Entity.getType()
9905	<< InheritedFrom;
9906
9907	RecordDecl *BaseDecl
9908	= Entity.getBaseSpecifier()->getType()->castAs<RecordType>()
9909	->getDecl();
9910	S.Diag(BaseDecl->getLocation(), diag::note_previous_decl)
9911	<< S.Context.getTagDeclType(BaseDecl);
9912	} else {
9913	S.Diag(Kind.getLocation(), diag::err_missing_default_ctor)
9914	<< (InheritedFrom ? 2 : Constructor->isImplicit() ? 1 : 0)
9915	<< S.Context.getTypeDeclType(Constructor->getParent())
9916	<< /*member=*/1
9917	<< Entity.getName()
9918	<< InheritedFrom;
9919	S.Diag(Entity.getDecl()->getLocation(),
9920	diag::note_member_declared_at);
9921
9922	if (const RecordType *Record
9923	= Entity.getType()->getAs<RecordType>())
9924	S.Diag(Record->getDecl()->getLocation(),
9925	diag::note_previous_decl)
9926	<< S.Context.getTagDeclType(Record->getDecl());
9927	}
9928	break;
9929	}
9930
9931	FailedCandidateSet.NoteCandidates(
9932	PartialDiagnosticAt(
9933	Kind.getLocation(),
9934	S.PDiag(diag::err_ovl_no_viable_function_in_init)
9935	<< DestType << ArgsRange),
9936	S, OCD_AllCandidates, Args);
9937	break;
9938
9939	case OR_Deleted: {
9940	OverloadCandidateSet::iterator Best;
9941	OverloadingResult Ovl
9942	= FailedCandidateSet.BestViableFunction(S, Loc: Kind.getLocation(), Best);
9943	if (Ovl != OR_Deleted) {
9944	S.Diag(Kind.getLocation(), diag::err_ovl_deleted_init)
9945	<< DestType << ArgsRange;
9946	llvm_unreachable("Inconsistent overload resolution?");
9947	break;
9948	}
9949
9950	// If this is a defaulted or implicitly-declared function, then
9951	// it was implicitly deleted. Make it clear that the deletion was
9952	// implicit.
9953	if (S.isImplicitlyDeleted(Best->Function))
9954	S.Diag(Kind.getLocation(), diag::err_ovl_deleted_special_init)
9955	<< S.getSpecialMember(cast<CXXMethodDecl>(Best->Function))
9956	<< DestType << ArgsRange;
9957	else
9958	S.Diag(Kind.getLocation(), diag::err_ovl_deleted_init)
9959	<< DestType << ArgsRange;
9960
9961	S.NoteDeletedFunction(FD: Best->Function);
9962	break;
9963	}
9964
9965	case OR_Success:
9966	llvm_unreachable("Conversion did not fail!");
9967	}
9968	}
9969	break;
9970
9971	case FK_DefaultInitOfConst:
9972	if (Entity.getKind() == InitializedEntity::EK_Member &&
9973	isa<CXXConstructorDecl>(Val: S.CurContext)) {
9974	// This is implicit default-initialization of a const member in
9975	// a constructor. Complain that it needs to be explicitly
9976	// initialized.
9977	CXXConstructorDecl *Constructor = cast<CXXConstructorDecl>(Val: S.CurContext);
9978	S.Diag(Kind.getLocation(), diag::err_uninitialized_member_in_ctor)
9979	<< (Constructor->getInheritedConstructor() ? 2 :
9980	Constructor->isImplicit() ? 1 : 0)
9981	<< S.Context.getTypeDeclType(Constructor->getParent())
9982	<< /*const=*/1
9983	<< Entity.getName();
9984	S.Diag(Entity.getDecl()->getLocation(), diag::note_previous_decl)
9985	<< Entity.getName();
9986	} else if (const auto *VD = dyn_cast_if_present<VarDecl>(Val: Entity.getDecl());
9987	VD && VD->isConstexpr()) {
9988	S.Diag(Kind.getLocation(), diag::err_constexpr_var_requires_const_init)
9989	<< VD;
9990	} else {
9991	S.Diag(Kind.getLocation(), diag::err_default_init_const)
9992	<< DestType << (bool)DestType->getAs<RecordType>();
9993	}
9994	break;
9995
9996	case FK_Incomplete:
9997	S.RequireCompleteType(Kind.getLocation(), FailedIncompleteType,
9998	diag::err_init_incomplete_type);
9999	break;
10000
10001	case FK_ListInitializationFailed: {
10002	// Run the init list checker again to emit diagnostics.
10003	InitListExpr *InitList = cast<InitListExpr>(Val: Args[0]);
10004	diagnoseListInit(S, Entity, InitList);
10005	break;
10006	}
10007
10008	case FK_PlaceholderType: {
10009	// FIXME: Already diagnosed!
10010	break;
10011	}
10012
10013	case FK_ExplicitConstructor: {
10014	S.Diag(Kind.getLocation(), diag::err_selected_explicit_constructor)
10015	<< Args[0]->getSourceRange();
10016	OverloadCandidateSet::iterator Best;
10017	OverloadingResult Ovl
10018	= FailedCandidateSet.BestViableFunction(S, Loc: Kind.getLocation(), Best);
10019	(void)Ovl;
10020	assert(Ovl == OR_Success && "Inconsistent overload resolution");
10021	CXXConstructorDecl *CtorDecl = cast<CXXConstructorDecl>(Val: Best->Function);
10022	S.Diag(CtorDecl->getLocation(),
10023	diag::note_explicit_ctor_deduction_guide_here) << false;
10024	break;
10025	}
10026
10027	case FK_ParenthesizedListInitFailed:
10028	TryOrBuildParenListInitialization(S, Entity, Kind, Args, Sequence&: *this,
10029	/*VerifyOnly=*/false);
10030	break;
10031
10032	case FK_DesignatedInitForNonAggregate:
10033	InitListExpr *InitList = cast<InitListExpr>(Val: Args[0]);
10034	S.Diag(Kind.getLocation(), diag::err_designated_init_for_non_aggregate)
10035	<< Entity.getType() << InitList->getSourceRange();
10036	break;
10037	}
10038
10039	PrintInitLocationNote(S, Entity);
10040	return true;
10041	}
10042
10043	void InitializationSequence::dump(raw_ostream &OS) const {
10044	switch (SequenceKind) {
10045	case FailedSequence: {
10046	OS << "Failed sequence: ";
10047	switch (Failure) {
10048	case FK_TooManyInitsForReference:
10049	OS << "too many initializers for reference";
10050	break;
10051
10052	case FK_ParenthesizedListInitForReference:
10053	OS << "parenthesized list init for reference";
10054	break;
10055
10056	case FK_ArrayNeedsInitList:
10057	OS << "array requires initializer list";
10058	break;
10059
10060	case FK_AddressOfUnaddressableFunction:
10061	OS << "address of unaddressable function was taken";
10062	break;
10063
10064	case FK_ArrayNeedsInitListOrStringLiteral:
10065	OS << "array requires initializer list or string literal";
10066	break;
10067
10068	case FK_ArrayNeedsInitListOrWideStringLiteral:
10069	OS << "array requires initializer list or wide string literal";
10070	break;
10071
10072	case FK_NarrowStringIntoWideCharArray:
10073	OS << "narrow string into wide char array";
10074	break;
10075
10076	case FK_WideStringIntoCharArray:
10077	OS << "wide string into char array";
10078	break;
10079
10080	case FK_IncompatWideStringIntoWideChar:
10081	OS << "incompatible wide string into wide char array";
10082	break;
10083
10084	case FK_PlainStringIntoUTF8Char:
10085	OS << "plain string literal into char8_t array";
10086	break;
10087
10088	case FK_UTF8StringIntoPlainChar:
10089	OS << "u8 string literal into char array";
10090	break;
10091
10092	case FK_ArrayTypeMismatch:
10093	OS << "array type mismatch";
10094	break;
10095
10096	case FK_NonConstantArrayInit:
10097	OS << "non-constant array initializer";
10098	break;
10099
10100	case FK_AddressOfOverloadFailed:
10101	OS << "address of overloaded function failed";
10102	break;
10103
10104	case FK_ReferenceInitOverloadFailed:
10105	OS << "overload resolution for reference initialization failed";
10106	break;
10107
10108	case FK_NonConstLValueReferenceBindingToTemporary:
10109	OS << "non-const lvalue reference bound to temporary";
10110	break;
10111
10112	case FK_NonConstLValueReferenceBindingToBitfield:
10113	OS << "non-const lvalue reference bound to bit-field";
10114	break;
10115
10116	case FK_NonConstLValueReferenceBindingToVectorElement:
10117	OS << "non-const lvalue reference bound to vector element";
10118	break;
10119
10120	case FK_NonConstLValueReferenceBindingToMatrixElement:
10121	OS << "non-const lvalue reference bound to matrix element";
10122	break;
10123
10124	case FK_NonConstLValueReferenceBindingToUnrelated:
10125	OS << "non-const lvalue reference bound to unrelated type";
10126	break;
10127
10128	case FK_RValueReferenceBindingToLValue:
10129	OS << "rvalue reference bound to an lvalue";
10130	break;
10131
10132	case FK_ReferenceInitDropsQualifiers:
10133	OS << "reference initialization drops qualifiers";
10134	break;
10135
10136	case FK_ReferenceAddrspaceMismatchTemporary:
10137	OS << "reference with mismatching address space bound to temporary";
10138	break;
10139
10140	case FK_ReferenceInitFailed:
10141	OS << "reference initialization failed";
10142	break;
10143
10144	case FK_ConversionFailed:
10145	OS << "conversion failed";
10146	break;
10147
10148	case FK_ConversionFromPropertyFailed:
10149	OS << "conversion from property failed";
10150	break;
10151
10152	case FK_TooManyInitsForScalar:
10153	OS << "too many initializers for scalar";
10154	break;
10155
10156	case FK_ParenthesizedListInitForScalar:
10157	OS << "parenthesized list init for reference";
10158	break;
10159
10160	case FK_ReferenceBindingToInitList:
10161	OS << "referencing binding to initializer list";
10162	break;
10163
10164	case FK_InitListBadDestinationType:
10165	OS << "initializer list for non-aggregate, non-scalar type";
10166	break;
10167
10168	case FK_UserConversionOverloadFailed:
10169	OS << "overloading failed for user-defined conversion";
10170	break;
10171
10172	case FK_ConstructorOverloadFailed:
10173	OS << "constructor overloading failed";
10174	break;
10175
10176	case FK_DefaultInitOfConst:
10177	OS << "default initialization of a const variable";
10178	break;
10179
10180	case FK_Incomplete:
10181	OS << "initialization of incomplete type";
10182	break;
10183
10184	case FK_ListInitializationFailed:
10185	OS << "list initialization checker failure";
10186	break;
10187
10188	case FK_VariableLengthArrayHasInitializer:
10189	OS << "variable length array has an initializer";
10190	break;
10191
10192	case FK_PlaceholderType:
10193	OS << "initializer expression isn't contextually valid";
10194	break;
10195
10196	case FK_ListConstructorOverloadFailed:
10197	OS << "list constructor overloading failed";
10198	break;
10199
10200	case FK_ExplicitConstructor:
10201	OS << "list copy initialization chose explicit constructor";
10202	break;
10203
10204	case FK_ParenthesizedListInitFailed:
10205	OS << "parenthesized list initialization failed";
10206	break;
10207
10208	case FK_DesignatedInitForNonAggregate:
10209	OS << "designated initializer for non-aggregate type";
10210	break;
10211	}
10212	OS << '\n';
10213	return;
10214	}
10215
10216	case DependentSequence:
10217	OS << "Dependent sequence\n";
10218	return;
10219
10220	case NormalSequence:
10221	OS << "Normal sequence: ";
10222	break;
10223	}
10224
10225	for (step_iterator S = step_begin(), SEnd = step_end(); S != SEnd; ++S) {
10226	if (S != step_begin()) {
10227	OS << " -> ";
10228	}
10229
10230	switch (S->Kind) {
10231	case SK_ResolveAddressOfOverloadedFunction:
10232	OS << "resolve address of overloaded function";
10233	break;
10234
10235	case SK_CastDerivedToBasePRValue:
10236	OS << "derived-to-base (prvalue)";
10237	break;
10238
10239	case SK_CastDerivedToBaseXValue:
10240	OS << "derived-to-base (xvalue)";
10241	break;
10242
10243	case SK_CastDerivedToBaseLValue:
10244	OS << "derived-to-base (lvalue)";
10245	break;
10246
10247	case SK_BindReference:
10248	OS << "bind reference to lvalue";
10249	break;
10250
10251	case SK_BindReferenceToTemporary:
10252	OS << "bind reference to a temporary";
10253	break;
10254
10255	case SK_FinalCopy:
10256	OS << "final copy in class direct-initialization";
10257	break;
10258
10259	case SK_ExtraneousCopyToTemporary:
10260	OS << "extraneous C++03 copy to temporary";
10261	break;
10262
10263	case SK_UserConversion:
10264	OS << "user-defined conversion via " << *S->Function.Function;
10265	break;
10266
10267	case SK_QualificationConversionPRValue:
10268	OS << "qualification conversion (prvalue)";
10269	break;
10270
10271	case SK_QualificationConversionXValue:
10272	OS << "qualification conversion (xvalue)";
10273	break;
10274
10275	case SK_QualificationConversionLValue:
10276	OS << "qualification conversion (lvalue)";
10277	break;
10278
10279	case SK_FunctionReferenceConversion:
10280	OS << "function reference conversion";
10281	break;
10282
10283	case SK_AtomicConversion:
10284	OS << "non-atomic-to-atomic conversion";
10285	break;
10286
10287	case SK_ConversionSequence:
10288	OS << "implicit conversion sequence (";
10289	S->ICS->dump(); // FIXME: use OS
10290	OS << ")";
10291	break;
10292
10293	case SK_ConversionSequenceNoNarrowing:
10294	OS << "implicit conversion sequence with narrowing prohibited (";
10295	S->ICS->dump(); // FIXME: use OS
10296	OS << ")";
10297	break;
10298
10299	case SK_ListInitialization:
10300	OS << "list aggregate initialization";
10301	break;
10302
10303	case SK_UnwrapInitList:
10304	OS << "unwrap reference initializer list";
10305	break;
10306
10307	case SK_RewrapInitList:
10308	OS << "rewrap reference initializer list";
10309	break;
10310
10311	case SK_ConstructorInitialization:
10312	OS << "constructor initialization";
10313	break;
10314
10315	case SK_ConstructorInitializationFromList:
10316	OS << "list initialization via constructor";
10317	break;
10318
10319	case SK_ZeroInitialization:
10320	OS << "zero initialization";
10321	break;
10322
10323	case SK_CAssignment:
10324	OS << "C assignment";
10325	break;
10326
10327	case SK_StringInit:
10328	OS << "string initialization";
10329	break;
10330
10331	case SK_ObjCObjectConversion:
10332	OS << "Objective-C object conversion";
10333	break;
10334
10335	case SK_ArrayLoopIndex:
10336	OS << "indexing for array initialization loop";
10337	break;
10338
10339	case SK_ArrayLoopInit:
10340	OS << "array initialization loop";
10341	break;
10342
10343	case SK_ArrayInit:
10344	OS << "array initialization";
10345	break;
10346
10347	case SK_GNUArrayInit:
10348	OS << "array initialization (GNU extension)";
10349	break;
10350
10351	case SK_ParenthesizedArrayInit:
10352	OS << "parenthesized array initialization";
10353	break;
10354
10355	case SK_PassByIndirectCopyRestore:
10356	OS << "pass by indirect copy and restore";
10357	break;
10358
10359	case SK_PassByIndirectRestore:
10360	OS << "pass by indirect restore";
10361	break;
10362
10363	case SK_ProduceObjCObject:
10364	OS << "Objective-C object retension";
10365	break;
10366
10367	case SK_StdInitializerList:
10368	OS << "std::initializer_list from initializer list";
10369	break;
10370
10371	case SK_StdInitializerListConstructorCall:
10372	OS << "list initialization from std::initializer_list";
10373	break;
10374
10375	case SK_OCLSamplerInit:
10376	OS << "OpenCL sampler_t from integer constant";
10377	break;
10378
10379	case SK_OCLZeroOpaqueType:
10380	OS << "OpenCL opaque type from zero";
10381	break;
10382	case SK_ParenthesizedListInit:
10383	OS << "initialization from a parenthesized list of values";
10384	break;
10385	}
10386
10387	OS << " [" << S->Type << ']';
10388	}
10389
10390	OS << '\n';
10391	}
10392
10393	void InitializationSequence::dump() const {
10394	dump(OS&: llvm::errs());
10395	}
10396
10397	static void DiagnoseNarrowingInInitList(Sema &S,
10398	const ImplicitConversionSequence &ICS,
10399	QualType PreNarrowingType,
10400	QualType EntityType,
10401	const Expr *PostInit) {
10402	const StandardConversionSequence *SCS = nullptr;
10403	switch (ICS.getKind()) {
10404	case ImplicitConversionSequence::StandardConversion:
10405	SCS = &ICS.Standard;
10406	break;
10407	case ImplicitConversionSequence::UserDefinedConversion:
10408	SCS = &ICS.UserDefined.After;
10409	break;
10410	case ImplicitConversionSequence::AmbiguousConversion:
10411	case ImplicitConversionSequence::StaticObjectArgumentConversion:
10412	case ImplicitConversionSequence::EllipsisConversion:
10413	case ImplicitConversionSequence::BadConversion:
10414	return;
10415	}
10416
10417	auto MakeDiag = [&](bool IsConstRef, unsigned DefaultDiagID,
10418	unsigned ConstRefDiagID, unsigned WarnDiagID) {
10419	unsigned DiagID;
10420	auto &L = S.getLangOpts();
10421	if (L.CPlusPlus11 &&
10422	(!L.MicrosoftExt || L.isCompatibleWithMSVC(MajorVersion: LangOptions::MSVC2015)))
10423	DiagID = IsConstRef ? ConstRefDiagID : DefaultDiagID;
10424	else
10425	DiagID = WarnDiagID;
10426	return S.Diag(PostInit->getBeginLoc(), DiagID)
10427	<< PostInit->getSourceRange();
10428	};
10429
10430	// C++11 [dcl.init.list]p7: Check whether this is a narrowing conversion.
10431	APValue ConstantValue;
10432	QualType ConstantType;
10433	switch (SCS->getNarrowingKind(Context&: S.Context, Converted: PostInit, ConstantValue,
10434	ConstantType)) {
10435	case NK_Not_Narrowing:
10436	case NK_Dependent_Narrowing:
10437	// No narrowing occurred.
10438	return;
10439
10440	case NK_Type_Narrowing: {
10441	// This was a floating-to-integer conversion, which is always considered a
10442	// narrowing conversion even if the value is a constant and can be
10443	// represented exactly as an integer.
10444	QualType T = EntityType.getNonReferenceType();
10445	MakeDiag(T != EntityType, diag::ext_init_list_type_narrowing,
10446	diag::ext_init_list_type_narrowing_const_reference,
10447	diag::warn_init_list_type_narrowing)
10448	<< PreNarrowingType.getLocalUnqualifiedType()
10449	<< T.getLocalUnqualifiedType();
10450	break;
10451	}
10452
10453	case NK_Constant_Narrowing: {
10454	// A constant value was narrowed.
10455	MakeDiag(EntityType.getNonReferenceType() != EntityType,
10456	diag::ext_init_list_constant_narrowing,
10457	diag::ext_init_list_constant_narrowing_const_reference,
10458	diag::warn_init_list_constant_narrowing)
10459	<< ConstantValue.getAsString(S.getASTContext(), ConstantType)
10460	<< EntityType.getNonReferenceType().getLocalUnqualifiedType();
10461	break;
10462	}
10463
10464	case NK_Variable_Narrowing: {
10465	// A variable's value may have been narrowed.
10466	MakeDiag(EntityType.getNonReferenceType() != EntityType,
10467	diag::ext_init_list_variable_narrowing,
10468	diag::ext_init_list_variable_narrowing_const_reference,
10469	diag::warn_init_list_variable_narrowing)
10470	<< PreNarrowingType.getLocalUnqualifiedType()
10471	<< EntityType.getNonReferenceType().getLocalUnqualifiedType();
10472	break;
10473	}
10474	}
10475
10476	SmallString<128> StaticCast;
10477	llvm::raw_svector_ostream OS(StaticCast);
10478	OS << "static_cast<";
10479	if (const TypedefType *TT = EntityType->getAs<TypedefType>()) {
10480	// It's important to use the typedef's name if there is one so that the
10481	// fixit doesn't break code using types like int64_t.
10482	//
10483	// FIXME: This will break if the typedef requires qualification. But
10484	// getQualifiedNameAsString() includes non-machine-parsable components.
10485	OS << *TT->getDecl();
10486	} else if (const BuiltinType *BT = EntityType->getAs<BuiltinType>())
10487	OS << BT->getName(Policy: S.getLangOpts());
10488	else {
10489	// Oops, we didn't find the actual type of the variable. Don't emit a fixit
10490	// with a broken cast.
10491	return;
10492	}
10493	OS << ">(";
10494	S.Diag(PostInit->getBeginLoc(), diag::note_init_list_narrowing_silence)
10495	<< PostInit->getSourceRange()
10496	<< FixItHint::CreateInsertion(PostInit->getBeginLoc(), OS.str())
10497	<< FixItHint::CreateInsertion(
10498	S.getLocForEndOfToken(PostInit->getEndLoc()), ")");
10499	}
10500
10501	//===----------------------------------------------------------------------===//
10502	// Initialization helper functions
10503	//===----------------------------------------------------------------------===//
10504	bool
10505	Sema::CanPerformCopyInitialization(const InitializedEntity &Entity,
10506	ExprResult Init) {
10507	if (Init.isInvalid())
10508	return false;
10509
10510	Expr *InitE = Init.get();
10511	assert(InitE && "No initialization expression");
10512
10513	InitializationKind Kind =
10514	InitializationKind::CreateCopy(InitLoc: InitE->getBeginLoc(), EqualLoc: SourceLocation());
10515	InitializationSequence Seq(*this, Entity, Kind, InitE);
10516	return !Seq.Failed();
10517	}
10518
10519	ExprResult
10520	Sema::PerformCopyInitialization(const InitializedEntity &Entity,
10521	SourceLocation EqualLoc,
10522	ExprResult Init,
10523	bool TopLevelOfInitList,
10524	bool AllowExplicit) {
10525	if (Init.isInvalid())
10526	return ExprError();
10527
10528	Expr *InitE = Init.get();
10529	assert(InitE && "No initialization expression?");
10530
10531	if (EqualLoc.isInvalid())
10532	EqualLoc = InitE->getBeginLoc();
10533
10534	InitializationKind Kind = InitializationKind::CreateCopy(
10535	InitLoc: InitE->getBeginLoc(), EqualLoc, AllowExplicitConvs: AllowExplicit);
10536	InitializationSequence Seq(*this, Entity, Kind, InitE, TopLevelOfInitList);
10537
10538	// Prevent infinite recursion when performing parameter copy-initialization.
10539	const bool ShouldTrackCopy =
10540	Entity.isParameterKind() && Seq.isConstructorInitialization();
10541	if (ShouldTrackCopy) {
10542	if (llvm::is_contained(Range&: CurrentParameterCopyTypes, Element: Entity.getType())) {
10543	Seq.SetOverloadFailure(
10544	Failure: InitializationSequence::FK_ConstructorOverloadFailed,
10545	Result: OR_No_Viable_Function);
10546
10547	// Try to give a meaningful diagnostic note for the problematic
10548	// constructor.
10549	const auto LastStep = Seq.step_end() - 1;
10550	assert(LastStep->Kind ==
10551	InitializationSequence::SK_ConstructorInitialization);
10552	const FunctionDecl *Function = LastStep->Function.Function;
10553	auto Candidate =
10554	llvm::find_if(Range&: Seq.getFailedCandidateSet(),
10555	P: [Function](const OverloadCandidate &Candidate) -> bool {
10556	return Candidate.Viable &&
10557	Candidate.Function == Function &&
10558	Candidate.Conversions.size() > 0;
10559	});
10560	if (Candidate != Seq.getFailedCandidateSet().end() &&
10561	Function->getNumParams() > 0) {
10562	Candidate->Viable = false;
10563	Candidate->FailureKind = ovl_fail_bad_conversion;
10564	Candidate->Conversions[0].setBad(BadConversionSequence::no_conversion,
10565	InitE,
10566	Function->getParamDecl(i: 0)->getType());
10567	}
10568	}
10569	CurrentParameterCopyTypes.push_back(Elt: Entity.getType());
10570	}
10571
10572	ExprResult Result = Seq.Perform(S&: *this, Entity, Kind, Args: InitE);
10573
10574	if (ShouldTrackCopy)
10575	CurrentParameterCopyTypes.pop_back();
10576
10577	return Result;
10578	}
10579
10580	/// Determine whether RD is, or is derived from, a specialization of CTD.
10581	static bool isOrIsDerivedFromSpecializationOf(CXXRecordDecl *RD,
10582	ClassTemplateDecl *CTD) {
10583	auto NotSpecialization = [&] (const CXXRecordDecl *Candidate) {
10584	auto *CTSD = dyn_cast<ClassTemplateSpecializationDecl>(Val: Candidate);
10585	return !CTSD || !declaresSameEntity(CTSD->getSpecializedTemplate(), CTD);
10586	};
10587	return !(NotSpecialization(RD) && RD->forallBases(NotSpecialization));
10588	}
10589
10590	QualType Sema::DeduceTemplateSpecializationFromInitializer(
10591	TypeSourceInfo *TSInfo, const InitializedEntity &Entity,
10592	const InitializationKind &Kind, MultiExprArg Inits) {
10593	auto *DeducedTST = dyn_cast<DeducedTemplateSpecializationType>(
10594	TSInfo->getType()->getContainedDeducedType());
10595	assert(DeducedTST && "not a deduced template specialization type");
10596
10597	auto TemplateName = DeducedTST->getTemplateName();
10598	if (TemplateName.isDependent())
10599	return SubstAutoTypeDependent(TypeWithAuto: TSInfo->getType());
10600
10601	// We can only perform deduction for class templates.
10602	auto *Template =
10603	dyn_cast_or_null<ClassTemplateDecl>(TemplateName.getAsTemplateDecl());
10604	if (!Template) {
10605	Diag(Kind.getLocation(),
10606	diag::err_deduced_non_class_template_specialization_type)
10607	<< (int)getTemplateNameKindForDiagnostics(TemplateName) << TemplateName;
10608	if (auto *TD = TemplateName.getAsTemplateDecl())
10609	NoteTemplateLocation(Decl: *TD);
10610	return QualType();
10611	}
10612
10613	// Can't deduce from dependent arguments.
10614	if (Expr::hasAnyTypeDependentArguments(Exprs: Inits)) {
10615	Diag(TSInfo->getTypeLoc().getBeginLoc(),
10616	diag::warn_cxx14_compat_class_template_argument_deduction)
10617	<< TSInfo->getTypeLoc().getSourceRange() << 0;
10618	return SubstAutoTypeDependent(TypeWithAuto: TSInfo->getType());
10619	}
10620
10621	// FIXME: Perform "exact type" matching first, per CWG discussion?
10622	// Or implement this via an implied 'T(T) -> T' deduction guide?
10623
10624	// FIXME: Do we need/want a std::initializer_list<T> special case?
10625
10626	// Look up deduction guides, including those synthesized from constructors.
10627	//
10628	// C++1z [over.match.class.deduct]p1:
10629	// A set of functions and function templates is formed comprising:
10630	// - For each constructor of the class template designated by the
10631	// template-name, a function template [...]
10632	// - For each deduction-guide, a function or function template [...]
10633	DeclarationNameInfo NameInfo(
10634	Context.DeclarationNames.getCXXDeductionGuideName(TD: Template),
10635	TSInfo->getTypeLoc().getEndLoc());
10636	LookupResult Guides(*this, NameInfo, LookupOrdinaryName);
10637	LookupQualifiedName(Guides, Template->getDeclContext());
10638
10639	// FIXME: Do not diagnose inaccessible deduction guides. The standard isn't
10640	// clear on this, but they're not found by name so access does not apply.
10641	Guides.suppressDiagnostics();
10642
10643	// Figure out if this is list-initialization.
10644	InitListExpr *ListInit =
10645	(Inits.size() == 1 && Kind.getKind() != InitializationKind::IK_Direct)
10646	? dyn_cast<InitListExpr>(Val: Inits[0])
10647	: nullptr;
10648
10649	// C++1z [over.match.class.deduct]p1:
10650	// Initialization and overload resolution are performed as described in
10651	// [dcl.init] and [over.match.ctor], [over.match.copy], or [over.match.list]
10652	// (as appropriate for the type of initialization performed) for an object
10653	// of a hypothetical class type, where the selected functions and function
10654	// templates are considered to be the constructors of that class type
10655	//
10656	// Since we know we're initializing a class type of a type unrelated to that
10657	// of the initializer, this reduces to something fairly reasonable.
10658	OverloadCandidateSet Candidates(Kind.getLocation(),
10659	OverloadCandidateSet::CSK_Normal);
10660	OverloadCandidateSet::iterator Best;
10661
10662	bool AllowExplicit = !Kind.isCopyInit() || ListInit;
10663
10664	// Return true if the candidate is added successfully, false otherwise.
10665	auto addDeductionCandidate = [&](FunctionTemplateDecl *TD,
10666	CXXDeductionGuideDecl *GD,
10667	DeclAccessPair FoundDecl,
10668	bool OnlyListConstructors,
10669	bool AllowAggregateDeductionCandidate) {
10670	// C++ [over.match.ctor]p1: (non-list copy-initialization from non-class)
10671	// For copy-initialization, the candidate functions are all the
10672	// converting constructors (12.3.1) of that class.
10673	// C++ [over.match.copy]p1: (non-list copy-initialization from class)
10674	// The converting constructors of T are candidate functions.
10675	if (!AllowExplicit) {
10676	// Overload resolution checks whether the deduction guide is declared
10677	// explicit for us.
10678
10679	// When looking for a converting constructor, deduction guides that
10680	// could never be called with one argument are not interesting to
10681	// check or note.
10682	if (GD->getMinRequiredArguments() > 1 ||
10683	(GD->getNumParams() == 0 && !GD->isVariadic()))
10684	return;
10685	}
10686
10687	// C++ [over.match.list]p1.1: (first phase list initialization)
10688	// Initially, the candidate functions are the initializer-list
10689	// constructors of the class T
10690	if (OnlyListConstructors && !isInitListConstructor(GD))
10691	return;
10692
10693	if (!AllowAggregateDeductionCandidate &&
10694	GD->getDeductionCandidateKind() == DeductionCandidate::Aggregate)
10695	return;
10696
10697	// C++ [over.match.list]p1.2: (second phase list initialization)
10698	// the candidate functions are all the constructors of the class T
10699	// C++ [over.match.ctor]p1: (all other cases)
10700	// the candidate functions are all the constructors of the class of
10701	// the object being initialized
10702
10703	// C++ [over.best.ics]p4:
10704	// When [...] the constructor [...] is a candidate by
10705	// - [over.match.copy] (in all cases)
10706	// FIXME: The "second phase of [over.match.list] case can also
10707	// theoretically happen here, but it's not clear whether we can
10708	// ever have a parameter of the right type.
10709	bool SuppressUserConversions = Kind.isCopyInit();
10710
10711	if (TD) {
10712	SmallVector<Expr *, 8> TmpInits;
10713	for (Expr *E : Inits)
10714	if (auto *DI = dyn_cast<DesignatedInitExpr>(Val: E))
10715	TmpInits.push_back(Elt: DI->getInit());
10716	else
10717	TmpInits.push_back(Elt: E);
10718	AddTemplateOverloadCandidate(
10719	FunctionTemplate: TD, FoundDecl, /*ExplicitArgs=*/ExplicitTemplateArgs: nullptr, Args: TmpInits, CandidateSet&: Candidates,
10720	SuppressUserConversions,
10721	/*PartialOverloading=*/false, AllowExplicit, IsADLCandidate: ADLCallKind::NotADL,
10722	/*PO=*/{}, AggregateCandidateDeduction: AllowAggregateDeductionCandidate);
10723	} else {
10724	AddOverloadCandidate(GD, FoundDecl, Inits, Candidates,
10725	SuppressUserConversions,
10726	/*PartialOverloading=*/false, AllowExplicit);
10727	}
10728	};
10729
10730	bool FoundDeductionGuide = false;
10731
10732	auto TryToResolveOverload =
10733	[&](bool OnlyListConstructors) -> OverloadingResult {
10734	Candidates.clear(CSK: OverloadCandidateSet::CSK_Normal);
10735	bool HasAnyDeductionGuide = false;
10736
10737	auto SynthesizeAggrGuide = [&](InitListExpr *ListInit) {
10738	auto *Pattern = Template;
10739	while (Pattern->getInstantiatedFromMemberTemplate()) {
10740	if (Pattern->isMemberSpecialization())
10741	break;
10742	Pattern = Pattern->getInstantiatedFromMemberTemplate();
10743	}
10744
10745	auto *RD = cast<CXXRecordDecl>(Pattern->getTemplatedDecl());
10746	if (!(RD->getDefinition() && RD->isAggregate()))
10747	return;
10748	QualType Ty = Context.getRecordType(Decl: RD);
10749	SmallVector<QualType, 8> ElementTypes;
10750
10751	InitListChecker CheckInitList(*this, Entity, ListInit, Ty, ElementTypes);
10752	if (!CheckInitList.HadError()) {
10753	// C++ [over.match.class.deduct]p1.8:
10754	// if e_i is of array type and x_i is a braced-init-list, T_i is an
10755	// rvalue reference to the declared type of e_i and
10756	// C++ [over.match.class.deduct]p1.9:
10757	// if e_i is of array type and x_i is a bstring-literal, T_i is an
10758	// lvalue reference to the const-qualified declared type of e_i and
10759	// C++ [over.match.class.deduct]p1.10:
10760	// otherwise, T_i is the declared type of e_i
10761	for (int I = 0, E = ListInit->getNumInits();
10762	I < E && !isa<PackExpansionType>(Val: ElementTypes[I]); ++I)
10763	if (ElementTypes[I]->isArrayType()) {
10764	if (isa<InitListExpr>(Val: ListInit->getInit(Init: I)))
10765	ElementTypes[I] = Context.getRValueReferenceType(T: ElementTypes[I]);
10766	else if (isa<StringLiteral>(
10767	Val: ListInit->getInit(Init: I)->IgnoreParenImpCasts()))
10768	ElementTypes[I] =
10769	Context.getLValueReferenceType(T: ElementTypes[I].withConst());
10770	}
10771
10772	llvm::FoldingSetNodeID ID;
10773	ID.AddPointer(Ptr: Template);
10774	for (auto &T : ElementTypes)
10775	T.getCanonicalType().Profile(ID);
10776	unsigned Hash = ID.ComputeHash();
10777	if (AggregateDeductionCandidates.count(Val: Hash) == 0) {
10778	if (FunctionTemplateDecl *TD =
10779	DeclareImplicitDeductionGuideFromInitList(
10780	Template: Template, ParamTypes: ElementTypes,
10781	Loc: TSInfo->getTypeLoc().getEndLoc())) {
10782	auto *GD = cast<CXXDeductionGuideDecl>(Val: TD->getTemplatedDecl());
10783	GD->setDeductionCandidateKind(DeductionCandidate::Aggregate);
10784	AggregateDeductionCandidates[Hash] = GD;
10785	addDeductionCandidate(TD, GD, DeclAccessPair::make(TD, AS_public),
10786	OnlyListConstructors,
10787	/*AllowAggregateDeductionCandidate=*/true);
10788	}
10789	} else {
10790	CXXDeductionGuideDecl *GD = AggregateDeductionCandidates[Hash];
10791	FunctionTemplateDecl *TD = GD->getDescribedFunctionTemplate();
10792	assert(TD && "aggregate deduction candidate is function template");
10793	addDeductionCandidate(TD, GD, DeclAccessPair::make(TD, AS_public),
10794	OnlyListConstructors,
10795	/*AllowAggregateDeductionCandidate=*/true);
10796	}
10797	HasAnyDeductionGuide = true;
10798	}
10799	};
10800
10801	for (auto I = Guides.begin(), E = Guides.end(); I != E; ++I) {
10802	NamedDecl *D = (*I)->getUnderlyingDecl();
10803	if (D->isInvalidDecl())
10804	continue;
10805
10806	auto *TD = dyn_cast<FunctionTemplateDecl>(Val: D);
10807	auto *GD = dyn_cast_if_present<CXXDeductionGuideDecl>(
10808	TD ? TD->getTemplatedDecl() : dyn_cast<FunctionDecl>(Val: D));
10809	if (!GD)
10810	continue;
10811
10812	if (!GD->isImplicit())
10813	HasAnyDeductionGuide = true;
10814
10815	addDeductionCandidate(TD, GD, I.getPair(), OnlyListConstructors,
10816	/*AllowAggregateDeductionCandidate=*/false);
10817	}
10818
10819	// C++ [over.match.class.deduct]p1.4:
10820	// if C is defined and its definition satisfies the conditions for an
10821	// aggregate class ([dcl.init.aggr]) with the assumption that any
10822	// dependent base class has no virtual functions and no virtual base
10823	// classes, and the initializer is a non-empty braced-init-list or
10824	// parenthesized expression-list, and there are no deduction-guides for
10825	// C, the set contains an additional function template, called the
10826	// aggregate deduction candidate, defined as follows.
10827	if (getLangOpts().CPlusPlus20 && !HasAnyDeductionGuide) {
10828	if (ListInit && ListInit->getNumInits()) {
10829	SynthesizeAggrGuide(ListInit);
10830	} else if (Inits.size()) { // parenthesized expression-list
10831	// Inits are expressions inside the parentheses. We don't have
10832	// the parentheses source locations, use the begin/end of Inits as the
10833	// best heuristic.
10834	InitListExpr TempListInit(getASTContext(), Inits.front()->getBeginLoc(),
10835	Inits, Inits.back()->getEndLoc());
10836	SynthesizeAggrGuide(&TempListInit);
10837	}
10838	}
10839
10840	FoundDeductionGuide = FoundDeductionGuide || HasAnyDeductionGuide;
10841
10842	return Candidates.BestViableFunction(S&: *this, Loc: Kind.getLocation(), Best);
10843	};
10844
10845	OverloadingResult Result = OR_No_Viable_Function;
10846
10847	// C++11 [over.match.list]p1, per DR1467: for list-initialization, first
10848	// try initializer-list constructors.
10849	if (ListInit) {
10850	bool TryListConstructors = true;
10851
10852	// Try list constructors unless the list is empty and the class has one or
10853	// more default constructors, in which case those constructors win.
10854	if (!ListInit->getNumInits()) {
10855	for (NamedDecl *D : Guides) {
10856	auto *FD = dyn_cast<FunctionDecl>(D->getUnderlyingDecl());
10857	if (FD && FD->getMinRequiredArguments() == 0) {
10858	TryListConstructors = false;
10859	break;
10860	}
10861	}
10862	} else if (ListInit->getNumInits() == 1) {
10863	// C++ [over.match.class.deduct]:
10864	// As an exception, the first phase in [over.match.list] (considering
10865	// initializer-list constructors) is omitted if the initializer list
10866	// consists of a single expression of type cv U, where U is a
10867	// specialization of C or a class derived from a specialization of C.
10868	Expr *E = ListInit->getInit(Init: 0);
10869	auto *RD = E->getType()->getAsCXXRecordDecl();
10870	if (!isa<InitListExpr>(Val: E) && RD &&
10871	isCompleteType(Loc: Kind.getLocation(), T: E->getType()) &&
10872	isOrIsDerivedFromSpecializationOf(RD, Template))
10873	TryListConstructors = false;
10874	}
10875
10876	if (TryListConstructors)
10877	Result = TryToResolveOverload(/*OnlyListConstructor*/true);
10878	// Then unwrap the initializer list and try again considering all
10879	// constructors.
10880	Inits = MultiExprArg(ListInit->getInits(), ListInit->getNumInits());
10881	}
10882
10883	// If list-initialization fails, or if we're doing any other kind of
10884	// initialization, we (eventually) consider constructors.
10885	if (Result == OR_No_Viable_Function)
10886	Result = TryToResolveOverload(/*OnlyListConstructor*/false);
10887
10888	switch (Result) {
10889	case OR_Ambiguous:
10890	// FIXME: For list-initialization candidates, it'd usually be better to
10891	// list why they were not viable when given the initializer list itself as
10892	// an argument.
10893	Candidates.NoteCandidates(
10894	PartialDiagnosticAt(
10895	Kind.getLocation(),
10896	PDiag(diag::err_deduced_class_template_ctor_ambiguous)
10897	<< TemplateName),
10898	*this, OCD_AmbiguousCandidates, Inits);
10899	return QualType();
10900
10901	case OR_No_Viable_Function: {
10902	CXXRecordDecl *Primary =
10903	cast<ClassTemplateDecl>(Template)->getTemplatedDecl();
10904	bool Complete =
10905	isCompleteType(Loc: Kind.getLocation(), T: Context.getTypeDeclType(Primary));
10906	Candidates.NoteCandidates(
10907	PartialDiagnosticAt(
10908	Kind.getLocation(),
10909	PDiag(Complete ? diag::err_deduced_class_template_ctor_no_viable
10910	: diag::err_deduced_class_template_incomplete)
10911	<< TemplateName << !Guides.empty()),
10912	*this, OCD_AllCandidates, Inits);
10913	return QualType();
10914	}
10915
10916	case OR_Deleted: {
10917	Diag(Kind.getLocation(), diag::err_deduced_class_template_deleted)
10918	<< TemplateName;
10919	NoteDeletedFunction(FD: Best->Function);
10920	return QualType();
10921	}
10922
10923	case OR_Success:
10924	// C++ [over.match.list]p1:
10925	// In copy-list-initialization, if an explicit constructor is chosen, the
10926	// initialization is ill-formed.
10927	if (Kind.isCopyInit() && ListInit &&
10928	cast<CXXDeductionGuideDecl>(Val: Best->Function)->isExplicit()) {
10929	bool IsDeductionGuide = !Best->Function->isImplicit();
10930	Diag(Kind.getLocation(), diag::err_deduced_class_template_explicit)
10931	<< TemplateName << IsDeductionGuide;
10932	Diag(Best->Function->getLocation(),
10933	diag::note_explicit_ctor_deduction_guide_here)
10934	<< IsDeductionGuide;
10935	return QualType();
10936	}
10937
10938	// Make sure we didn't select an unusable deduction guide, and mark it
10939	// as referenced.
10940	DiagnoseUseOfDecl(D: Best->FoundDecl, Locs: Kind.getLocation());
10941	MarkFunctionReferenced(Loc: Kind.getLocation(), Func: Best->Function);
10942	break;
10943	}
10944
10945	// C++ [dcl.type.class.deduct]p1:
10946	// The placeholder is replaced by the return type of the function selected
10947	// by overload resolution for class template deduction.
10948	QualType DeducedType =
10949	SubstAutoType(TypeWithAuto: TSInfo->getType(), Replacement: Best->Function->getReturnType());
10950	Diag(TSInfo->getTypeLoc().getBeginLoc(),
10951	diag::warn_cxx14_compat_class_template_argument_deduction)
10952	<< TSInfo->getTypeLoc().getSourceRange() << 1 << DeducedType;
10953
10954	// Warn if CTAD was used on a type that does not have any user-defined
10955	// deduction guides.
10956	if (!FoundDeductionGuide) {
10957	Diag(TSInfo->getTypeLoc().getBeginLoc(),
10958	diag::warn_ctad_maybe_unsupported)
10959	<< TemplateName;
10960	Diag(Template->getLocation(), diag::note_suppress_ctad_maybe_unsupported);
10961	}
10962
10963	return DeducedType;
10964	}
10965