1	//===--- ParseTemplate.cpp - Template Parsing -----------------------------===//
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 parsing of C++ templates.
10	//
11	//===----------------------------------------------------------------------===//
12
13	#include "clang/AST/ASTContext.h"
14	#include "clang/AST/DeclTemplate.h"
15	#include "clang/AST/ExprCXX.h"
16	#include "clang/Basic/DiagnosticParse.h"
17	#include "clang/Parse/Parser.h"
18	#include "clang/Parse/RAIIObjectsForParser.h"
19	#include "clang/Sema/DeclSpec.h"
20	#include "clang/Sema/EnterExpressionEvaluationContext.h"
21	#include "clang/Sema/ParsedTemplate.h"
22	#include "clang/Sema/Scope.h"
23	using namespace clang;
24
25	unsigned Parser::ReenterTemplateScopes(MultiParseScope &S, Decl *D) {
26	return Actions.ActOnReenterTemplateScope(Template: D, EnterScope: [&] {
27	S.Enter(ScopeFlags: Scope::TemplateParamScope);
28	return Actions.getCurScope();
29	});
30	}
31
32	Parser::DeclGroupPtrTy
33	Parser::ParseDeclarationStartingWithTemplate(DeclaratorContext Context,
34	SourceLocation &DeclEnd,
35	ParsedAttributes &AccessAttrs) {
36	ObjCDeclContextSwitch ObjCDC(*this);
37
38	if (Tok.is(K: tok::kw_template) && NextToken().isNot(K: tok::less)) {
39	return ParseExplicitInstantiation(Context, ExternLoc: SourceLocation(), TemplateLoc: ConsumeToken(),
40	DeclEnd, AccessAttrs,
41	AS: AccessSpecifier::AS_none);
42	}
43	return ParseTemplateDeclarationOrSpecialization(Context, DeclEnd, AccessAttrs,
44	AS: AccessSpecifier::AS_none);
45	}
46
47	Parser::DeclGroupPtrTy Parser::ParseTemplateDeclarationOrSpecialization(
48	DeclaratorContext Context, SourceLocation &DeclEnd,
49	ParsedAttributes &AccessAttrs, AccessSpecifier AS) {
50	assert(Tok.isOneOf(tok::kw_export, tok::kw_template) &&
51	"Token does not start a template declaration.");
52
53	MultiParseScope TemplateParamScopes(*this);
54
55	// Tell the action that names should be checked in the context of
56	// the declaration to come.
57	ParsingDeclRAIIObject
58	ParsingTemplateParams(*this, ParsingDeclRAIIObject::NoParent);
59
60	// Parse multiple levels of template headers within this template
61	// parameter scope, e.g.,
62	//
63	// template<typename T>
64	// template<typename U>
65	// class A<T>::B { ... };
66	//
67	// We parse multiple levels non-recursively so that we can build a
68	// single data structure containing all of the template parameter
69	// lists to easily differentiate between the case above and:
70	//
71	// template<typename T>
72	// class A {
73	// template<typename U> class B;
74	// };
75	//
76	// In the first case, the action for declaring A<T>::B receives
77	// both template parameter lists. In the second case, the action for
78	// defining A<T>::B receives just the inner template parameter list
79	// (and retrieves the outer template parameter list from its
80	// context).
81	bool isSpecialization = true;
82	bool LastParamListWasEmpty = false;
83	TemplateParameterLists ParamLists;
84	TemplateParameterDepthRAII CurTemplateDepthTracker(TemplateParameterDepth);
85
86	do {
87	// Consume the 'export', if any.
88	SourceLocation ExportLoc;
89	TryConsumeToken(Expected: tok::kw_export, Loc&: ExportLoc);
90
91	// Consume the 'template', which should be here.
92	SourceLocation TemplateLoc;
93	if (!TryConsumeToken(Expected: tok::kw_template, Loc&: TemplateLoc)) {
94	Diag(Tok.getLocation(), diag::err_expected_template);
95	return nullptr;
96	}
97
98	// Parse the '<' template-parameter-list '>'
99	SourceLocation LAngleLoc, RAngleLoc;
100	SmallVector<NamedDecl*, 4> TemplateParams;
101	if (ParseTemplateParameters(TemplateScopes&: TemplateParamScopes,
102	Depth: CurTemplateDepthTracker.getDepth(),
103	TemplateParams, LAngleLoc, RAngleLoc)) {
104	// Skip until the semi-colon or a '}'.
105	SkipUntil(T: tok::r_brace, Flags: StopAtSemi | StopBeforeMatch);
106	TryConsumeToken(Expected: tok::semi);
107	return nullptr;
108	}
109
110	ExprResult OptionalRequiresClauseConstraintER;
111	if (!TemplateParams.empty()) {
112	isSpecialization = false;
113	++CurTemplateDepthTracker;
114
115	if (TryConsumeToken(Expected: tok::kw_requires)) {
116	OptionalRequiresClauseConstraintER =
117	Actions.ActOnRequiresClause(ConstraintExpr: ParseConstraintLogicalOrExpression(
118	/*IsTrailingRequiresClause=*/false));
119	if (!OptionalRequiresClauseConstraintER.isUsable()) {
120	// Skip until the semi-colon or a '}'.
121	SkipUntil(T: tok::r_brace, Flags: StopAtSemi | StopBeforeMatch);
122	TryConsumeToken(Expected: tok::semi);
123	return nullptr;
124	}
125	}
126	} else {
127	LastParamListWasEmpty = true;
128	}
129
130	ParamLists.push_back(Elt: Actions.ActOnTemplateParameterList(
131	Depth: CurTemplateDepthTracker.getDepth(), ExportLoc, TemplateLoc, LAngleLoc,
132	Params: TemplateParams, RAngleLoc, RequiresClause: OptionalRequiresClauseConstraintER.get()));
133	} while (Tok.isOneOf(K1: tok::kw_export, K2: tok::kw_template));
134
135	ParsedTemplateInfo TemplateInfo(&ParamLists, isSpecialization,
136	LastParamListWasEmpty);
137
138	// Parse the actual template declaration.
139	if (Tok.is(K: tok::kw_concept)) {
140	Decl *ConceptDecl = ParseConceptDefinition(TemplateInfo, DeclEnd);
141	// We need to explicitly pass ConceptDecl to ParsingDeclRAIIObject, so that
142	// delayed diagnostics (e.g. warn_deprecated) have a Decl to work with.
143	ParsingTemplateParams.complete(D: ConceptDecl);
144	return Actions.ConvertDeclToDeclGroup(Ptr: ConceptDecl);
145	}
146
147	return ParseDeclarationAfterTemplate(
148	Context, TemplateInfo, DiagsFromParams&: ParsingTemplateParams, DeclEnd, AccessAttrs, AS);
149	}
150
151	Parser::DeclGroupPtrTy Parser::ParseTemplateDeclarationOrSpecialization(
152	DeclaratorContext Context, SourceLocation &DeclEnd, AccessSpecifier AS) {
153	ParsedAttributes AccessAttrs(AttrFactory);
154	return ParseTemplateDeclarationOrSpecialization(Context, DeclEnd, AccessAttrs,
155	AS);
156	}
157
158	Parser::DeclGroupPtrTy Parser::ParseDeclarationAfterTemplate(
159	DeclaratorContext Context, ParsedTemplateInfo &TemplateInfo,
160	ParsingDeclRAIIObject &DiagsFromTParams, SourceLocation &DeclEnd,
161	ParsedAttributes &AccessAttrs, AccessSpecifier AS) {
162	assert(TemplateInfo.Kind != ParsedTemplateKind::NonTemplate &&
163	"Template information required");
164
165	if (Tok.is(K: tok::kw_static_assert)) {
166	// A static_assert declaration may not be templated.
167	Diag(Tok.getLocation(), diag::err_templated_invalid_declaration)
168	<< TemplateInfo.getSourceRange();
169	// Parse the static_assert declaration to improve error recovery.
170	return Actions.ConvertDeclToDeclGroup(
171	Ptr: ParseStaticAssertDeclaration(DeclEnd));
172	}
173
174	// We are parsing a member template.
175	if (Context == DeclaratorContext::Member)
176	return ParseCXXClassMemberDeclaration(AS, Attr&: AccessAttrs, TemplateInfo,
177	DiagsFromTParams: &DiagsFromTParams);
178
179	ParsedAttributes DeclAttrs(AttrFactory);
180	ParsedAttributes DeclSpecAttrs(AttrFactory);
181
182	// GNU attributes are applied to the declaration specification while the
183	// standard attributes are applied to the declaration. We parse the two
184	// attribute sets into different containters so we can apply them during
185	// the regular parsing process.
186	while (MaybeParseCXX11Attributes(Attrs&: DeclAttrs) ||
187	MaybeParseGNUAttributes(Attrs&: DeclSpecAttrs))
188	;
189
190	if (Tok.is(K: tok::kw_using))
191	return ParseUsingDirectiveOrDeclaration(Context, TemplateInfo, DeclEnd,
192	Attrs&: DeclAttrs);
193
194	// Parse the declaration specifiers, stealing any diagnostics from
195	// the template parameters.
196	ParsingDeclSpec DS(*this, &DiagsFromTParams);
197	DS.SetRangeStart(DeclSpecAttrs.Range.getBegin());
198	DS.SetRangeEnd(DeclSpecAttrs.Range.getEnd());
199	DS.takeAttributesFrom(attrs&: DeclSpecAttrs);
200
201	ParseDeclarationSpecifiers(DS, TemplateInfo, AS,
202	DSC: getDeclSpecContextFromDeclaratorContext(Context));
203
204	if (Tok.is(K: tok::semi)) {
205	ProhibitAttributes(Attrs&: DeclAttrs);
206	DeclEnd = ConsumeToken();
207	RecordDecl *AnonRecord = nullptr;
208	Decl *Decl = Actions.ParsedFreeStandingDeclSpec(
209	S: getCurScope(), AS, DS, DeclAttrs: ParsedAttributesView::none(),
210	TemplateParams: TemplateInfo.TemplateParams ? *TemplateInfo.TemplateParams
211	: MultiTemplateParamsArg(),
212	IsExplicitInstantiation: TemplateInfo.Kind == ParsedTemplateKind::ExplicitInstantiation,
213	AnonRecord);
214	Actions.ActOnDefinedDeclarationSpecifier(D: Decl);
215	assert(!AnonRecord &&
216	"Anonymous unions/structs should not be valid with template");
217	DS.complete(D: Decl);
218	return Actions.ConvertDeclToDeclGroup(Ptr: Decl);
219	}
220
221	if (DS.hasTagDefinition())
222	Actions.ActOnDefinedDeclarationSpecifier(D: DS.getRepAsDecl());
223
224	// Move the attributes from the prefix into the DS.
225	if (TemplateInfo.Kind == ParsedTemplateKind::ExplicitInstantiation)
226	ProhibitAttributes(Attrs&: DeclAttrs);
227
228	return ParseDeclGroup(DS, Context, Attrs&: DeclAttrs, TemplateInfo, DeclEnd: &DeclEnd);
229	}
230
231	Decl *
232	Parser::ParseConceptDefinition(const ParsedTemplateInfo &TemplateInfo,
233	SourceLocation &DeclEnd) {
234	assert(TemplateInfo.Kind != ParsedTemplateKind::NonTemplate &&
235	"Template information required");
236	assert(Tok.is(tok::kw_concept) &&
237	"ParseConceptDefinition must be called when at a 'concept' keyword");
238
239	ConsumeToken(); // Consume 'concept'
240
241	SourceLocation BoolKWLoc;
242	if (TryConsumeToken(tok::kw_bool, BoolKWLoc))
243	Diag(Tok.getLocation(), diag::err_concept_legacy_bool_keyword) <<
244	FixItHint::CreateRemoval(SourceLocation(BoolKWLoc));
245
246	DiagnoseAndSkipCXX11Attributes();
247
248	CXXScopeSpec SS;
249	if (ParseOptionalCXXScopeSpecifier(
250	SS, /*ObjectType=*/nullptr,
251	/*ObjectHasErrors=*/false, /*EnteringContext=*/false,
252	/*MayBePseudoDestructor=*/nullptr,
253	/*IsTypename=*/false, /*LastII=*/nullptr, /*OnlyNamespace=*/true) ||
254	SS.isInvalid()) {
255	SkipUntil(T: tok::semi);
256	return nullptr;
257	}
258
259	if (SS.isNotEmpty())
260	Diag(SS.getBeginLoc(),
261	diag::err_concept_definition_not_identifier);
262
263	UnqualifiedId Result;
264	if (ParseUnqualifiedId(SS, /*ObjectType=*/nullptr,
265	/*ObjectHadErrors=*/false, /*EnteringContext=*/false,
266	/*AllowDestructorName=*/false,
267	/*AllowConstructorName=*/false,
268	/*AllowDeductionGuide=*/false,
269	/*TemplateKWLoc=*/nullptr, Result)) {
270	SkipUntil(T: tok::semi);
271	return nullptr;
272	}
273
274	if (Result.getKind() != UnqualifiedIdKind::IK_Identifier) {
275	Diag(Result.getBeginLoc(), diag::err_concept_definition_not_identifier);
276	SkipUntil(T: tok::semi);
277	return nullptr;
278	}
279
280	const IdentifierInfo *Id = Result.Identifier;
281	SourceLocation IdLoc = Result.getBeginLoc();
282
283	// [C++26][basic.scope.pdecl]/p13
284	// The locus of a concept-definition is immediately after its concept-name.
285	ConceptDecl *D = Actions.ActOnStartConceptDefinition(
286	S: getCurScope(), TemplateParameterLists: *TemplateInfo.TemplateParams, Name: Id, NameLoc: IdLoc);
287
288	ParsedAttributes Attrs(AttrFactory);
289	MaybeParseAttributes(WhichAttrKinds: PAKM_GNU | PAKM_CXX11, Attrs);
290
291	if (!TryConsumeToken(Expected: tok::equal)) {
292	Diag(Tok.getLocation(), diag::err_expected) << tok::equal;
293	SkipUntil(T: tok::semi);
294	if (D)
295	D->setInvalidDecl();
296	return nullptr;
297	}
298
299	ExprResult ConstraintExprResult =
300	Actions.CorrectDelayedTyposInExpr(ER: ParseConstraintExpression());
301	if (ConstraintExprResult.isInvalid()) {
302	SkipUntil(T: tok::semi);
303	if (D)
304	D->setInvalidDecl();
305	return nullptr;
306	}
307
308	DeclEnd = Tok.getLocation();
309	ExpectAndConsumeSemi(diag::err_expected_semi_declaration);
310	Expr *ConstraintExpr = ConstraintExprResult.get();
311
312	if (!D)
313	return nullptr;
314
315	return Actions.ActOnFinishConceptDefinition(S: getCurScope(), C: D, ConstraintExpr,
316	Attrs);
317	}
318
319	bool Parser::ParseTemplateParameters(
320	MultiParseScope &TemplateScopes, unsigned Depth,
321	SmallVectorImpl<NamedDecl *> &TemplateParams, SourceLocation &LAngleLoc,
322	SourceLocation &RAngleLoc) {
323	// Get the template parameter list.
324	if (!TryConsumeToken(Expected: tok::less, Loc&: LAngleLoc)) {
325	Diag(Tok.getLocation(), diag::err_expected_less_after) << "template";
326	return true;
327	}
328
329	// Try to parse the template parameter list.
330	bool Failed = false;
331	// FIXME: Missing greatergreatergreater support.
332	if (!Tok.is(K: tok::greater) && !Tok.is(K: tok::greatergreater)) {
333	TemplateScopes.Enter(ScopeFlags: Scope::TemplateParamScope);
334	Failed = ParseTemplateParameterList(Depth, TemplateParams);
335	}
336
337	if (Tok.is(K: tok::greatergreater)) {
338	// No diagnostic required here: a template-parameter-list can only be
339	// followed by a declaration or, for a template template parameter, the
340	// 'class' keyword. Therefore, the second '>' will be diagnosed later.
341	// This matters for elegant diagnosis of:
342	// template<template<typename>> struct S;
343	Tok.setKind(tok::greater);
344	RAngleLoc = Tok.getLocation();
345	Tok.setLocation(Tok.getLocation().getLocWithOffset(Offset: 1));
346	} else if (!TryConsumeToken(Expected: tok::greater, Loc&: RAngleLoc) && Failed) {
347	Diag(Tok.getLocation(), diag::err_expected) << tok::greater;
348	return true;
349	}
350	return false;
351	}
352
353	bool
354	Parser::ParseTemplateParameterList(const unsigned Depth,
355	SmallVectorImpl<NamedDecl*> &TemplateParams) {
356	while (true) {
357
358	if (NamedDecl *TmpParam
359	= ParseTemplateParameter(Depth, Position: TemplateParams.size())) {
360	TemplateParams.push_back(Elt: TmpParam);
361	} else {
362	// If we failed to parse a template parameter, skip until we find
363	// a comma or closing brace.
364	SkipUntil(T1: tok::comma, T2: tok::greater, T3: tok::greatergreater,
365	Flags: StopAtSemi | StopBeforeMatch);
366	}
367
368	// Did we find a comma or the end of the template parameter list?
369	if (Tok.is(K: tok::comma)) {
370	ConsumeToken();
371	} else if (Tok.isOneOf(K1: tok::greater, K2: tok::greatergreater)) {
372	// Don't consume this... that's done by template parser.
373	break;
374	} else {
375	// Somebody probably forgot to close the template. Skip ahead and
376	// try to get out of the expression. This error is currently
377	// subsumed by whatever goes on in ParseTemplateParameter.
378	Diag(Tok.getLocation(), diag::err_expected_comma_greater);
379	SkipUntil(T1: tok::comma, T2: tok::greater, T3: tok::greatergreater,
380	Flags: StopAtSemi | StopBeforeMatch);
381	return false;
382	}
383	}
384	return true;
385	}
386
387	Parser::TPResult Parser::isStartOfTemplateTypeParameter() {
388	if (Tok.is(K: tok::kw_class)) {
389	// "class" may be the start of an elaborated-type-specifier or a
390	// type-parameter. Per C++ [temp.param]p3, we prefer the type-parameter.
391	switch (NextToken().getKind()) {
392	case tok::equal:
393	case tok::comma:
394	case tok::greater:
395	case tok::greatergreater:
396	case tok::ellipsis:
397	return TPResult::True;
398
399	case tok::identifier:
400	// This may be either a type-parameter or an elaborated-type-specifier.
401	// We have to look further.
402	break;
403
404	default:
405	return TPResult::False;
406	}
407
408	switch (GetLookAheadToken(N: 2).getKind()) {
409	case tok::equal:
410	case tok::comma:
411	case tok::greater:
412	case tok::greatergreater:
413	return TPResult::True;
414
415	default:
416	return TPResult::False;
417	}
418	}
419
420	if (TryAnnotateTypeConstraint())
421	return TPResult::Error;
422
423	if (isTypeConstraintAnnotation() &&
424	// Next token might be 'auto' or 'decltype', indicating that this
425	// type-constraint is in fact part of a placeholder-type-specifier of a
426	// non-type template parameter.
427	!GetLookAheadToken(N: Tok.is(K: tok::annot_cxxscope) ? 2 : 1)
428	.isOneOf(K1: tok::kw_auto, K2: tok::kw_decltype))
429	return TPResult::True;
430
431	// 'typedef' is a reasonably-common typo/thinko for 'typename', and is
432	// ill-formed otherwise.
433	if (Tok.isNot(K: tok::kw_typename) && Tok.isNot(K: tok::kw_typedef))
434	return TPResult::False;
435
436	// C++ [temp.param]p2:
437	// There is no semantic difference between class and typename in a
438	// template-parameter. typename followed by an unqualified-id
439	// names a template type parameter. typename followed by a
440	// qualified-id denotes the type in a non-type
441	// parameter-declaration.
442	Token Next = NextToken();
443
444	// If we have an identifier, skip over it.
445	if (Next.getKind() == tok::identifier)
446	Next = GetLookAheadToken(N: 2);
447
448	switch (Next.getKind()) {
449	case tok::equal:
450	case tok::comma:
451	case tok::greater:
452	case tok::greatergreater:
453	case tok::ellipsis:
454	return TPResult::True;
455
456	case tok::kw_typename:
457	case tok::kw_typedef:
458	case tok::kw_class:
459	// These indicate that a comma was missed after a type parameter, not that
460	// we have found a non-type parameter.
461	return TPResult::True;
462
463	default:
464	return TPResult::False;
465	}
466	}
467
468	NamedDecl *Parser::ParseTemplateParameter(unsigned Depth, unsigned Position) {
469
470	switch (isStartOfTemplateTypeParameter()) {
471	case TPResult::True:
472	// Is there just a typo in the input code? ('typedef' instead of
473	// 'typename')
474	if (Tok.is(K: tok::kw_typedef)) {
475	Diag(Tok.getLocation(), diag::err_expected_template_parameter);
476
477	Diag(Tok.getLocation(), diag::note_meant_to_use_typename)
478	<< FixItHint::CreateReplacement(CharSourceRange::getCharRange(
479	Tok.getLocation(),
480	Tok.getEndLoc()),
481	"typename");
482
483	Tok.setKind(tok::kw_typename);
484	}
485
486	return ParseTypeParameter(Depth, Position);
487	case TPResult::False:
488	break;
489
490	case TPResult::Error: {
491	// We return an invalid parameter as opposed to null to avoid having bogus
492	// diagnostics about an empty template parameter list.
493	// FIXME: Fix ParseTemplateParameterList to better handle nullptr results
494	// from here.
495	// Return a NTTP as if there was an error in a scope specifier, the user
496	// probably meant to write the type of a NTTP.
497	DeclSpec DS(getAttrFactory());
498	DS.SetTypeSpecError();
499	Declarator D(DS, ParsedAttributesView::none(),
500	DeclaratorContext::TemplateParam);
501	D.SetIdentifier(Id: nullptr, IdLoc: Tok.getLocation());
502	D.setInvalidType(true);
503	NamedDecl *ErrorParam = Actions.ActOnNonTypeTemplateParameter(
504	S: getCurScope(), D, Depth, Position, /*EqualLoc=*/SourceLocation(),
505	/*DefaultArg=*/nullptr);
506	ErrorParam->setInvalidDecl(true);
507	SkipUntil(T1: tok::comma, T2: tok::greater, T3: tok::greatergreater,
508	Flags: StopAtSemi | StopBeforeMatch);
509	return ErrorParam;
510	}
511
512	case TPResult::Ambiguous:
513	llvm_unreachable("template param classification can't be ambiguous");
514	}
515
516	if (Tok.is(K: tok::kw_template))
517	return ParseTemplateTemplateParameter(Depth, Position);
518
519	// If it's none of the above, then it must be a parameter declaration.
520	// NOTE: This will pick up errors in the closure of the template parameter
521	// list (e.g., template < ; Check here to implement >> style closures.
522	return ParseNonTypeTemplateParameter(Depth, Position);
523	}
524
525	bool Parser::isTypeConstraintAnnotation() {
526	const Token &T = Tok.is(K: tok::annot_cxxscope) ? NextToken() : Tok;
527	if (T.isNot(K: tok::annot_template_id))
528	return false;
529	const auto *ExistingAnnot =
530	static_cast<TemplateIdAnnotation *>(T.getAnnotationValue());
531	return ExistingAnnot->Kind == TNK_Concept_template;
532	}
533
534	bool Parser::TryAnnotateTypeConstraint() {
535	if (!getLangOpts().CPlusPlus20)
536	return false;
537	CXXScopeSpec SS;
538	bool WasScopeAnnotation = Tok.is(K: tok::annot_cxxscope);
539	if (ParseOptionalCXXScopeSpecifier(SS, /*ObjectType=*/nullptr,
540	/*ObjectHasErrors=*/false,
541	/*EnteringContext=*/false,
542	/*MayBePseudoDestructor=*/nullptr,
543	// If this is not a type-constraint, then
544	// this scope-spec is part of the typename
545	// of a non-type template parameter
546	/*IsTypename=*/true, /*LastII=*/nullptr,
547	// We won't find concepts in
548	// non-namespaces anyway, so might as well
549	// parse this correctly for possible type
550	// names.
551	/*OnlyNamespace=*/false))
552	return true;
553
554	if (Tok.is(K: tok::identifier)) {
555	UnqualifiedId PossibleConceptName;
556	PossibleConceptName.setIdentifier(Id: Tok.getIdentifierInfo(),
557	IdLoc: Tok.getLocation());
558
559	TemplateTy PossibleConcept;
560	bool MemberOfUnknownSpecialization = false;
561	auto TNK = Actions.isTemplateName(S: getCurScope(), SS,
562	/*hasTemplateKeyword=*/false,
563	Name: PossibleConceptName,
564	/*ObjectType=*/ParsedType(),
565	/*EnteringContext=*/false,
566	Template&: PossibleConcept,
567	MemberOfUnknownSpecialization,
568	/*Disambiguation=*/true);
569	if (MemberOfUnknownSpecialization || !PossibleConcept ||
570	TNK != TNK_Concept_template) {
571	if (SS.isNotEmpty())
572	AnnotateScopeToken(SS, IsNewAnnotation: !WasScopeAnnotation);
573	return false;
574	}
575
576	// At this point we're sure we're dealing with a constrained parameter. It
577	// may or may not have a template parameter list following the concept
578	// name.
579	if (AnnotateTemplateIdToken(Template: PossibleConcept, TNK, SS,
580	/*TemplateKWLoc=*/SourceLocation(),
581	TemplateName&: PossibleConceptName,
582	/*AllowTypeAnnotation=*/false,
583	/*TypeConstraint=*/true))
584	return true;
585	}
586
587	if (SS.isNotEmpty())
588	AnnotateScopeToken(SS, IsNewAnnotation: !WasScopeAnnotation);
589	return false;
590	}
591
592	NamedDecl *Parser::ParseTypeParameter(unsigned Depth, unsigned Position) {
593	assert((Tok.isOneOf(tok::kw_class, tok::kw_typename) ||
594	isTypeConstraintAnnotation()) &&
595	"A type-parameter starts with 'class', 'typename' or a "
596	"type-constraint");
597
598	CXXScopeSpec TypeConstraintSS;
599	TemplateIdAnnotation *TypeConstraint = nullptr;
600	bool TypenameKeyword = false;
601	SourceLocation KeyLoc;
602	ParseOptionalCXXScopeSpecifier(SS&: TypeConstraintSS, /*ObjectType=*/nullptr,
603	/*ObjectHasErrors=*/false,
604	/*EnteringContext*/ false);
605	if (Tok.is(K: tok::annot_template_id)) {
606	// Consume the 'type-constraint'.
607	TypeConstraint =
608	static_cast<TemplateIdAnnotation *>(Tok.getAnnotationValue());
609	assert(TypeConstraint->Kind == TNK_Concept_template &&
610	"stray non-concept template-id annotation");
611	KeyLoc = ConsumeAnnotationToken();
612	} else {
613	assert(TypeConstraintSS.isEmpty() &&
614	"expected type constraint after scope specifier");
615
616	// Consume the 'class' or 'typename' keyword.
617	TypenameKeyword = Tok.is(K: tok::kw_typename);
618	KeyLoc = ConsumeToken();
619	}
620
621	// Grab the ellipsis (if given).
622	SourceLocation EllipsisLoc;
623	if (TryConsumeToken(Expected: tok::ellipsis, Loc&: EllipsisLoc)) {
624	Diag(EllipsisLoc,
625	getLangOpts().CPlusPlus11
626	? diag::warn_cxx98_compat_variadic_templates
627	: diag::ext_variadic_templates);
628	}
629
630	// Grab the template parameter name (if given)
631	SourceLocation NameLoc = Tok.getLocation();
632	IdentifierInfo *ParamName = nullptr;
633	if (Tok.is(K: tok::identifier)) {
634	ParamName = Tok.getIdentifierInfo();
635	ConsumeToken();
636	} else if (Tok.isOneOf(K1: tok::equal, Ks: tok::comma, Ks: tok::greater,
637	Ks: tok::greatergreater)) {
638	// Unnamed template parameter. Don't have to do anything here, just
639	// don't consume this token.
640	} else {
641	Diag(Tok.getLocation(), diag::err_expected) << tok::identifier;
642	return nullptr;
643	}
644
645	// Recover from misplaced ellipsis.
646	bool AlreadyHasEllipsis = EllipsisLoc.isValid();
647	if (TryConsumeToken(Expected: tok::ellipsis, Loc&: EllipsisLoc))
648	DiagnoseMisplacedEllipsis(EllipsisLoc, CorrectLoc: NameLoc, AlreadyHasEllipsis, IdentifierHasName: true);
649
650	// Grab a default argument (if available).
651	// Per C++0x [basic.scope.pdecl]p9, we parse the default argument before
652	// we introduce the type parameter into the local scope.
653	SourceLocation EqualLoc;
654	ParsedType DefaultArg;
655	std::optional<DelayTemplateIdDestructionRAII> DontDestructTemplateIds;
656	if (TryConsumeToken(Expected: tok::equal, Loc&: EqualLoc)) {
657	// The default argument might contain a lambda declaration; avoid destroying
658	// parsed template ids at the end of that declaration because they can be
659	// used in a type constraint later.
660	DontDestructTemplateIds.emplace(args&: *this, /*DelayTemplateIdDestruction=*/args: true);
661	// The default argument may declare template parameters, notably
662	// if it contains a generic lambda, so we need to increase
663	// the template depth as these parameters would not be instantiated
664	// at the current level.
665	TemplateParameterDepthRAII CurTemplateDepthTracker(TemplateParameterDepth);
666	++CurTemplateDepthTracker;
667	DefaultArg =
668	ParseTypeName(/*Range=*/nullptr, Context: DeclaratorContext::TemplateTypeArg)
669	.get();
670	}
671
672	NamedDecl *NewDecl = Actions.ActOnTypeParameter(S: getCurScope(),
673	Typename: TypenameKeyword, EllipsisLoc,
674	KeyLoc, ParamName, ParamNameLoc: NameLoc,
675	Depth, Position, EqualLoc,
676	DefaultArg,
677	HasTypeConstraint: TypeConstraint != nullptr);
678
679	if (TypeConstraint) {
680	Actions.ActOnTypeConstraint(SS: TypeConstraintSS, TypeConstraint,
681	ConstrainedParameter: cast<TemplateTypeParmDecl>(Val: NewDecl),
682	EllipsisLoc);
683	}
684
685	return NewDecl;
686	}
687
688	NamedDecl *Parser::ParseTemplateTemplateParameter(unsigned Depth,
689	unsigned Position) {
690	assert(Tok.is(tok::kw_template) && "Expected 'template' keyword");
691
692	// Handle the template <...> part.
693	SourceLocation TemplateLoc = ConsumeToken();
694	SmallVector<NamedDecl*,8> TemplateParams;
695	SourceLocation LAngleLoc, RAngleLoc;
696	ExprResult OptionalRequiresClauseConstraintER;
697	{
698	MultiParseScope TemplateParmScope(*this);
699	if (ParseTemplateParameters(TemplateScopes&: TemplateParmScope, Depth: Depth + 1, TemplateParams,
700	LAngleLoc, RAngleLoc)) {
701	return nullptr;
702	}
703	if (TryConsumeToken(Expected: tok::kw_requires)) {
704	OptionalRequiresClauseConstraintER =
705	Actions.ActOnRequiresClause(ConstraintExpr: ParseConstraintLogicalOrExpression(
706	/*IsTrailingRequiresClause=*/false));
707	if (!OptionalRequiresClauseConstraintER.isUsable()) {
708	SkipUntil(T1: tok::comma, T2: tok::greater, T3: tok::greatergreater,
709	Flags: StopAtSemi | StopBeforeMatch);
710	return nullptr;
711	}
712	}
713	}
714
715	// Provide an ExtWarn if the C++1z feature of using 'typename' here is used.
716	// Generate a meaningful error if the user forgot to put class before the
717	// identifier, comma, or greater. Provide a fixit if the identifier, comma,
718	// or greater appear immediately or after 'struct'. In the latter case,
719	// replace the keyword with 'class'.
720	bool TypenameKeyword = false;
721	if (!TryConsumeToken(Expected: tok::kw_class)) {
722	bool Replace = Tok.isOneOf(K1: tok::kw_typename, K2: tok::kw_struct);
723	const Token &Next = Tok.is(K: tok::kw_struct) ? NextToken() : Tok;
724	if (Tok.is(K: tok::kw_typename)) {
725	TypenameKeyword = true;
726	Diag(Tok.getLocation(),
727	getLangOpts().CPlusPlus17
728	? diag::warn_cxx14_compat_template_template_param_typename
729	: diag::ext_template_template_param_typename)
730	<< (!getLangOpts().CPlusPlus17
731	? FixItHint::CreateReplacement(Tok.getLocation(), "class")
732	: FixItHint());
733	} else if (Next.isOneOf(K1: tok::identifier, Ks: tok::comma, Ks: tok::greater,
734	Ks: tok::greatergreater, Ks: tok::ellipsis)) {
735	Diag(Tok.getLocation(), diag::err_class_on_template_template_param)
736	<< getLangOpts().CPlusPlus17
737	<< (Replace
738	? FixItHint::CreateReplacement(Tok.getLocation(), "class")
739	: FixItHint::CreateInsertion(Tok.getLocation(), "class "));
740	} else
741	Diag(Tok.getLocation(), diag::err_class_on_template_template_param)
742	<< getLangOpts().CPlusPlus17;
743
744	if (Replace)
745	ConsumeToken();
746	}
747
748	// Parse the ellipsis, if given.
749	SourceLocation EllipsisLoc;
750	if (TryConsumeToken(tok::ellipsis, EllipsisLoc))
751	Diag(EllipsisLoc,
752	getLangOpts().CPlusPlus11
753	? diag::warn_cxx98_compat_variadic_templates
754	: diag::ext_variadic_templates);
755
756	// Get the identifier, if given.
757	SourceLocation NameLoc = Tok.getLocation();
758	IdentifierInfo *ParamName = nullptr;
759	if (Tok.is(K: tok::identifier)) {
760	ParamName = Tok.getIdentifierInfo();
761	ConsumeToken();
762	} else if (Tok.isOneOf(K1: tok::equal, Ks: tok::comma, Ks: tok::greater,
763	Ks: tok::greatergreater)) {
764	// Unnamed template parameter. Don't have to do anything here, just
765	// don't consume this token.
766	} else {
767	Diag(Tok.getLocation(), diag::err_expected) << tok::identifier;
768	return nullptr;
769	}
770
771	// Recover from misplaced ellipsis.
772	bool AlreadyHasEllipsis = EllipsisLoc.isValid();
773	if (TryConsumeToken(Expected: tok::ellipsis, Loc&: EllipsisLoc))
774	DiagnoseMisplacedEllipsis(EllipsisLoc, CorrectLoc: NameLoc, AlreadyHasEllipsis, IdentifierHasName: true);
775
776	TemplateParameterList *ParamList = Actions.ActOnTemplateParameterList(
777	Depth, ExportLoc: SourceLocation(), TemplateLoc, LAngleLoc, Params: TemplateParams,
778	RAngleLoc, RequiresClause: OptionalRequiresClauseConstraintER.get());
779
780	// Grab a default argument (if available).
781	// Per C++0x [basic.scope.pdecl]p9, we parse the default argument before
782	// we introduce the template parameter into the local scope.
783	SourceLocation EqualLoc;
784	ParsedTemplateArgument DefaultArg;
785	if (TryConsumeToken(Expected: tok::equal, Loc&: EqualLoc)) {
786	DefaultArg = ParseTemplateTemplateArgument();
787	if (DefaultArg.isInvalid()) {
788	Diag(Tok.getLocation(),
789	diag::err_default_template_template_parameter_not_template);
790	SkipUntil(T1: tok::comma, T2: tok::greater, T3: tok::greatergreater,
791	Flags: StopAtSemi | StopBeforeMatch);
792	}
793	}
794
795	return Actions.ActOnTemplateTemplateParameter(
796	S: getCurScope(), TmpLoc: TemplateLoc, Params: ParamList, Typename: TypenameKeyword, EllipsisLoc,
797	ParamName, ParamNameLoc: NameLoc, Depth, Position, EqualLoc, DefaultArg);
798	}
799
800	NamedDecl *
801	Parser::ParseNonTypeTemplateParameter(unsigned Depth, unsigned Position) {
802	// Parse the declaration-specifiers (i.e., the type).
803	// FIXME: The type should probably be restricted in some way... Not all
804	// declarators (parts of declarators?) are accepted for parameters.
805	DeclSpec DS(AttrFactory);
806	ParsedTemplateInfo TemplateInfo;
807	ParseDeclarationSpecifiers(DS, TemplateInfo, AS: AS_none,
808	DSC: DeclSpecContext::DSC_template_param);
809
810	// Parse this as a typename.
811	Declarator ParamDecl(DS, ParsedAttributesView::none(),
812	DeclaratorContext::TemplateParam);
813	ParseDeclarator(D&: ParamDecl);
814	if (DS.getTypeSpecType() == DeclSpec::TST_unspecified) {
815	Diag(Tok.getLocation(), diag::err_expected_template_parameter);
816	return nullptr;
817	}
818
819	// Recover from misplaced ellipsis.
820	SourceLocation EllipsisLoc;
821	if (TryConsumeToken(Expected: tok::ellipsis, Loc&: EllipsisLoc))
822	DiagnoseMisplacedEllipsisInDeclarator(EllipsisLoc, D&: ParamDecl);
823
824	// If there is a default value, parse it.
825	// Per C++0x [basic.scope.pdecl]p9, we parse the default argument before
826	// we introduce the template parameter into the local scope.
827	SourceLocation EqualLoc;
828	ExprResult DefaultArg;
829	if (TryConsumeToken(Expected: tok::equal, Loc&: EqualLoc)) {
830	if (Tok.is(K: tok::l_paren) && NextToken().is(K: tok::l_brace)) {
831	Diag(Tok.getLocation(), diag::err_stmt_expr_in_default_arg) << 1;
832	SkipUntil(T1: tok::comma, T2: tok::greater, Flags: StopAtSemi | StopBeforeMatch);
833	} else {
834	// C++ [temp.param]p15:
835	// When parsing a default template-argument for a non-type
836	// template-parameter, the first non-nested > is taken as the
837	// end of the template-parameter-list rather than a greater-than
838	// operator.
839	GreaterThanIsOperatorScope G(GreaterThanIsOperator, false);
840
841	// The default argument may declare template parameters, notably
842	// if it contains a generic lambda, so we need to increase
843	// the template depth as these parameters would not be instantiated
844	// at the current level.
845	TemplateParameterDepthRAII CurTemplateDepthTracker(
846	TemplateParameterDepth);
847	++CurTemplateDepthTracker;
848	EnterExpressionEvaluationContext ConstantEvaluated(
849	Actions, Sema::ExpressionEvaluationContext::ConstantEvaluated);
850	DefaultArg = Actions.ActOnConstantExpression(Res: ParseInitializer());
851	if (DefaultArg.isInvalid())
852	SkipUntil(T1: tok::comma, T2: tok::greater, Flags: StopAtSemi | StopBeforeMatch);
853	}
854	}
855
856	// Create the parameter.
857	return Actions.ActOnNonTypeTemplateParameter(S: getCurScope(), D&: ParamDecl,
858	Depth, Position, EqualLoc,
859	DefaultArg: DefaultArg.get());
860	}
861
862	void Parser::DiagnoseMisplacedEllipsis(SourceLocation EllipsisLoc,
863	SourceLocation CorrectLoc,
864	bool AlreadyHasEllipsis,
865	bool IdentifierHasName) {
866	FixItHint Insertion;
867	if (!AlreadyHasEllipsis)
868	Insertion = FixItHint::CreateInsertion(InsertionLoc: CorrectLoc, Code: "...");
869	Diag(EllipsisLoc, diag::err_misplaced_ellipsis_in_declaration)
870	<< FixItHint::CreateRemoval(EllipsisLoc) << Insertion
871	<< !IdentifierHasName;
872	}
873
874	void Parser::DiagnoseMisplacedEllipsisInDeclarator(SourceLocation EllipsisLoc,
875	Declarator &D) {
876	assert(EllipsisLoc.isValid());
877	bool AlreadyHasEllipsis = D.getEllipsisLoc().isValid();
878	if (!AlreadyHasEllipsis)
879	D.setEllipsisLoc(EllipsisLoc);
880	DiagnoseMisplacedEllipsis(EllipsisLoc, CorrectLoc: D.getIdentifierLoc(),
881	AlreadyHasEllipsis, IdentifierHasName: D.hasName());
882	}
883
884	bool Parser::ParseGreaterThanInTemplateList(SourceLocation LAngleLoc,
885	SourceLocation &RAngleLoc,
886	bool ConsumeLastToken,
887	bool ObjCGenericList) {
888	// What will be left once we've consumed the '>'.
889	tok::TokenKind RemainingToken;
890	const char *ReplacementStr = "> >";
891	bool MergeWithNextToken = false;
892
893	switch (Tok.getKind()) {
894	default:
895	Diag(getEndOfPreviousToken(), diag::err_expected) << tok::greater;
896	Diag(LAngleLoc, diag::note_matching) << tok::less;
897	return true;
898
899	case tok::greater:
900	// Determine the location of the '>' token. Only consume this token
901	// if the caller asked us to.
902	RAngleLoc = Tok.getLocation();
903	if (ConsumeLastToken)
904	ConsumeToken();
905	return false;
906
907	case tok::greatergreater:
908	RemainingToken = tok::greater;
909	break;
910
911	case tok::greatergreatergreater:
912	RemainingToken = tok::greatergreater;
913	break;
914
915	case tok::greaterequal:
916	RemainingToken = tok::equal;
917	ReplacementStr = "> =";
918
919	// Join two adjacent '=' tokens into one, for cases like:
920	// void (*p)() = f<int>;
921	// return f<int>==p;
922	if (NextToken().is(K: tok::equal) &&
923	areTokensAdjacent(A: Tok, B: NextToken())) {
924	RemainingToken = tok::equalequal;
925	MergeWithNextToken = true;
926	}
927	break;
928
929	case tok::greatergreaterequal:
930	RemainingToken = tok::greaterequal;
931	break;
932	}
933
934	// This template-id is terminated by a token that starts with a '>'.
935	// Outside C++11 and Objective-C, this is now error recovery.
936	//
937	// C++11 allows this when the token is '>>', and in CUDA + C++11 mode, we
938	// extend that treatment to also apply to the '>>>' token.
939	//
940	// Objective-C allows this in its type parameter / argument lists.
941
942	SourceLocation TokBeforeGreaterLoc = PrevTokLocation;
943	SourceLocation TokLoc = Tok.getLocation();
944	Token Next = NextToken();
945
946	// Whether splitting the current token after the '>' would undesirably result
947	// in the remaining token pasting with the token after it. This excludes the
948	// MergeWithNextToken cases, which we've already handled.
949	bool PreventMergeWithNextToken =
950	(RemainingToken == tok::greater ||
951	RemainingToken == tok::greatergreater) &&
952	(Next.isOneOf(K1: tok::greater, Ks: tok::greatergreater,
953	Ks: tok::greatergreatergreater, Ks: tok::equal, Ks: tok::greaterequal,
954	Ks: tok::greatergreaterequal, Ks: tok::equalequal)) &&
955	areTokensAdjacent(A: Tok, B: Next);
956
957	// Diagnose this situation as appropriate.
958	if (!ObjCGenericList) {
959	// The source range of the replaced token(s).
960	CharSourceRange ReplacementRange = CharSourceRange::getCharRange(
961	B: TokLoc, E: Lexer::AdvanceToTokenCharacter(TokStart: TokLoc, Characters: 2, SM: PP.getSourceManager(),
962	LangOpts: getLangOpts()));
963
964	// A hint to put a space between the '>>'s. In order to make the hint as
965	// clear as possible, we include the characters either side of the space in
966	// the replacement, rather than just inserting a space at SecondCharLoc.
967	FixItHint Hint1 = FixItHint::CreateReplacement(RemoveRange: ReplacementRange,
968	Code: ReplacementStr);
969
970	// A hint to put another space after the token, if it would otherwise be
971	// lexed differently.
972	FixItHint Hint2;
973	if (PreventMergeWithNextToken)
974	Hint2 = FixItHint::CreateInsertion(InsertionLoc: Next.getLocation(), Code: " ");
975
976	unsigned DiagId = diag::err_two_right_angle_brackets_need_space;
977	if (getLangOpts().CPlusPlus11 &&
978	(Tok.is(tok::greatergreater) || Tok.is(tok::greatergreatergreater)))
979	DiagId = diag::warn_cxx98_compat_two_right_angle_brackets;
980	else if (Tok.is(tok::greaterequal))
981	DiagId = diag::err_right_angle_bracket_equal_needs_space;
982	Diag(Loc: TokLoc, DiagID: DiagId) << Hint1 << Hint2;
983	}
984
985	// Find the "length" of the resulting '>' token. This is not always 1, as it
986	// can contain escaped newlines.
987	unsigned GreaterLength = Lexer::getTokenPrefixLength(
988	TokStart: TokLoc, CharNo: 1, SM: PP.getSourceManager(), LangOpts: getLangOpts());
989
990	// Annotate the source buffer to indicate that we split the token after the
991	// '>'. This allows us to properly find the end of, and extract the spelling
992	// of, the '>' token later.
993	RAngleLoc = PP.SplitToken(TokLoc, Length: GreaterLength);
994
995	// Strip the initial '>' from the token.
996	bool CachingTokens = PP.IsPreviousCachedToken(Tok);
997
998	Token Greater = Tok;
999	Greater.setLocation(RAngleLoc);
1000	Greater.setKind(tok::greater);
1001	Greater.setLength(GreaterLength);
1002
1003	unsigned OldLength = Tok.getLength();
1004	if (MergeWithNextToken) {
1005	ConsumeToken();
1006	OldLength += Tok.getLength();
1007	}
1008
1009	Tok.setKind(RemainingToken);
1010	Tok.setLength(OldLength - GreaterLength);
1011
1012	// Split the second token if lexing it normally would lex a different token
1013	// (eg, the fifth token in 'A<B>>>' should re-lex as '>', not '>>').
1014	SourceLocation AfterGreaterLoc = TokLoc.getLocWithOffset(Offset: GreaterLength);
1015	if (PreventMergeWithNextToken)
1016	AfterGreaterLoc = PP.SplitToken(TokLoc: AfterGreaterLoc, Length: Tok.getLength());
1017	Tok.setLocation(AfterGreaterLoc);
1018
1019	// Update the token cache to match what we just did if necessary.
1020	if (CachingTokens) {
1021	// If the previous cached token is being merged, delete it.
1022	if (MergeWithNextToken)
1023	PP.ReplacePreviousCachedToken(NewToks: {});
1024
1025	if (ConsumeLastToken)
1026	PP.ReplacePreviousCachedToken(NewToks: {Greater, Tok});
1027	else
1028	PP.ReplacePreviousCachedToken(NewToks: {Greater});
1029	}
1030
1031	if (ConsumeLastToken) {
1032	PrevTokLocation = RAngleLoc;
1033	} else {
1034	PrevTokLocation = TokBeforeGreaterLoc;
1035	PP.EnterToken(Tok, /*IsReinject=*/true);
1036	Tok = Greater;
1037	}
1038
1039	return false;
1040	}
1041
1042	bool Parser::ParseTemplateIdAfterTemplateName(bool ConsumeLastToken,
1043	SourceLocation &LAngleLoc,
1044	TemplateArgList &TemplateArgs,
1045	SourceLocation &RAngleLoc,
1046	TemplateTy Template) {
1047	assert(Tok.is(tok::less) && "Must have already parsed the template-name");
1048
1049	// Consume the '<'.
1050	LAngleLoc = ConsumeToken();
1051
1052	// Parse the optional template-argument-list.
1053	bool Invalid = false;
1054	{
1055	GreaterThanIsOperatorScope G(GreaterThanIsOperator, false);
1056	if (!Tok.isOneOf(K1: tok::greater, Ks: tok::greatergreater,
1057	Ks: tok::greatergreatergreater, Ks: tok::greaterequal,
1058	Ks: tok::greatergreaterequal))
1059	Invalid = ParseTemplateArgumentList(TemplateArgs, Template, OpenLoc: LAngleLoc);
1060
1061	if (Invalid) {
1062	// Try to find the closing '>'.
1063	if (getLangOpts().CPlusPlus11)
1064	SkipUntil(T1: tok::greater, T2: tok::greatergreater,
1065	T3: tok::greatergreatergreater, Flags: StopAtSemi | StopBeforeMatch);
1066	else
1067	SkipUntil(T: tok::greater, Flags: StopAtSemi | StopBeforeMatch);
1068	}
1069	}
1070
1071	return ParseGreaterThanInTemplateList(LAngleLoc, RAngleLoc, ConsumeLastToken,
1072	/*ObjCGenericList=*/false) ||
1073	Invalid;
1074	}
1075
1076	bool Parser::AnnotateTemplateIdToken(TemplateTy Template, TemplateNameKind TNK,
1077	CXXScopeSpec &SS,
1078	SourceLocation TemplateKWLoc,
1079	UnqualifiedId &TemplateName,
1080	bool AllowTypeAnnotation,
1081	bool TypeConstraint) {
1082	assert(getLangOpts().CPlusPlus && "Can only annotate template-ids in C++");
1083	assert((Tok.is(tok::less) || TypeConstraint) &&
1084	"Parser isn't at the beginning of a template-id");
1085	assert(!(TypeConstraint && AllowTypeAnnotation) && "type-constraint can't be "
1086	"a type annotation");
1087	assert((!TypeConstraint || TNK == TNK_Concept_template) && "type-constraint "
1088	"must accompany a concept name");
1089	assert((Template || TNK == TNK_Non_template) && "missing template name");
1090
1091	// Consume the template-name.
1092	SourceLocation TemplateNameLoc = TemplateName.getSourceRange().getBegin();
1093
1094	// Parse the enclosed template argument list.
1095	SourceLocation LAngleLoc, RAngleLoc;
1096	TemplateArgList TemplateArgs;
1097	bool ArgsInvalid = false;
1098	if (!TypeConstraint || Tok.is(K: tok::less)) {
1099	ArgsInvalid = ParseTemplateIdAfterTemplateName(
1100	ConsumeLastToken: false, LAngleLoc, TemplateArgs, RAngleLoc, Template);
1101	// If we couldn't recover from invalid arguments, don't form an annotation
1102	// token -- we don't know how much to annotate.
1103	// FIXME: This can lead to duplicate diagnostics if we retry parsing this
1104	// template-id in another context. Try to annotate anyway?
1105	if (RAngleLoc.isInvalid())
1106	return true;
1107	}
1108
1109	ASTTemplateArgsPtr TemplateArgsPtr(TemplateArgs);
1110
1111	// Build the annotation token.
1112	if (TNK == TNK_Type_template && AllowTypeAnnotation) {
1113	TypeResult Type = ArgsInvalid
1114	? TypeError()
1115	: Actions.ActOnTemplateIdType(
1116	S: getCurScope(), SS, TemplateKWLoc, Template,
1117	TemplateII: TemplateName.Identifier, TemplateIILoc: TemplateNameLoc,
1118	LAngleLoc, TemplateArgs: TemplateArgsPtr, RAngleLoc);
1119
1120	Tok.setKind(tok::annot_typename);
1121	setTypeAnnotation(Tok, T: Type);
1122	if (SS.isNotEmpty())
1123	Tok.setLocation(SS.getBeginLoc());
1124	else if (TemplateKWLoc.isValid())
1125	Tok.setLocation(TemplateKWLoc);
1126	else
1127	Tok.setLocation(TemplateNameLoc);
1128	} else {
1129	// Build a template-id annotation token that can be processed
1130	// later.
1131	Tok.setKind(tok::annot_template_id);
1132
1133	const IdentifierInfo *TemplateII =
1134	TemplateName.getKind() == UnqualifiedIdKind::IK_Identifier
1135	? TemplateName.Identifier
1136	: nullptr;
1137
1138	OverloadedOperatorKind OpKind =
1139	TemplateName.getKind() == UnqualifiedIdKind::IK_Identifier
1140	? OO_None
1141	: TemplateName.OperatorFunctionId.Operator;
1142
1143	TemplateIdAnnotation *TemplateId = TemplateIdAnnotation::Create(
1144	TemplateKWLoc, TemplateNameLoc, Name: TemplateII, OperatorKind: OpKind, OpaqueTemplateName: Template, TemplateKind: TNK,
1145	LAngleLoc, RAngleLoc, TemplateArgs, ArgsInvalid, CleanupList&: TemplateIds);
1146
1147	Tok.setAnnotationValue(TemplateId);
1148	if (TemplateKWLoc.isValid())
1149	Tok.setLocation(TemplateKWLoc);
1150	else
1151	Tok.setLocation(TemplateNameLoc);
1152	}
1153
1154	// Common fields for the annotation token
1155	Tok.setAnnotationEndLoc(RAngleLoc);
1156
1157	// In case the tokens were cached, have Preprocessor replace them with the
1158	// annotation token.
1159	PP.AnnotateCachedTokens(Tok);
1160	return false;
1161	}
1162
1163	void Parser::AnnotateTemplateIdTokenAsType(
1164	CXXScopeSpec &SS, ImplicitTypenameContext AllowImplicitTypename,
1165	bool IsClassName) {
1166	assert(Tok.is(tok::annot_template_id) && "Requires template-id tokens");
1167
1168	TemplateIdAnnotation *TemplateId = takeTemplateIdAnnotation(tok: Tok);
1169	assert(TemplateId->mightBeType() &&
1170	"Only works for type and dependent templates");
1171
1172	ASTTemplateArgsPtr TemplateArgsPtr(TemplateId->getTemplateArgs(),
1173	TemplateId->NumArgs);
1174
1175	TypeResult Type =
1176	TemplateId->isInvalid()
1177	? TypeError()
1178	: Actions.ActOnTemplateIdType(
1179	S: getCurScope(), SS, TemplateKWLoc: TemplateId->TemplateKWLoc,
1180	Template: TemplateId->Template, TemplateII: TemplateId->Name,
1181	TemplateIILoc: TemplateId->TemplateNameLoc, LAngleLoc: TemplateId->LAngleLoc,
1182	TemplateArgs: TemplateArgsPtr, RAngleLoc: TemplateId->RAngleLoc,
1183	/*IsCtorOrDtorName=*/false, IsClassName, AllowImplicitTypename);
1184	// Create the new "type" annotation token.
1185	Tok.setKind(tok::annot_typename);
1186	setTypeAnnotation(Tok, T: Type);
1187	if (SS.isNotEmpty()) // it was a C++ qualified type name.
1188	Tok.setLocation(SS.getBeginLoc());
1189	// End location stays the same
1190
1191	// Replace the template-id annotation token, and possible the scope-specifier
1192	// that precedes it, with the typename annotation token.
1193	PP.AnnotateCachedTokens(Tok);
1194	}
1195
1196	/// Determine whether the given token can end a template argument.
1197	static bool isEndOfTemplateArgument(Token Tok) {
1198	// FIXME: Handle '>>>'.
1199	return Tok.isOneOf(K1: tok::comma, Ks: tok::greater, Ks: tok::greatergreater,
1200	Ks: tok::greatergreatergreater);
1201	}
1202
1203	ParsedTemplateArgument Parser::ParseTemplateTemplateArgument() {
1204	if (!Tok.is(K: tok::identifier) && !Tok.is(K: tok::coloncolon) &&
1205	!Tok.is(K: tok::annot_cxxscope))
1206	return ParsedTemplateArgument();
1207
1208	// C++0x [temp.arg.template]p1:
1209	// A template-argument for a template template-parameter shall be the name
1210	// of a class template or an alias template, expressed as id-expression.
1211	//
1212	// We parse an id-expression that refers to a class template or alias
1213	// template. The grammar we parse is:
1214	//
1215	// nested-name-specifier[opt] template[opt] identifier ...[opt]
1216	//
1217	// followed by a token that terminates a template argument, such as ',',
1218	// '>', or (in some cases) '>>'.
1219	CXXScopeSpec SS; // nested-name-specifier, if present
1220	ParseOptionalCXXScopeSpecifier(SS, /*ObjectType=*/nullptr,
1221	/*ObjectHasErrors=*/false,
1222	/*EnteringContext=*/false);
1223
1224	ParsedTemplateArgument Result;
1225	SourceLocation EllipsisLoc;
1226	if (SS.isSet() && Tok.is(K: tok::kw_template)) {
1227	// Parse the optional 'template' keyword following the
1228	// nested-name-specifier.
1229	SourceLocation TemplateKWLoc = ConsumeToken();
1230
1231	if (Tok.is(K: tok::identifier)) {
1232	// We appear to have a dependent template name.
1233	UnqualifiedId Name;
1234	Name.setIdentifier(Id: Tok.getIdentifierInfo(), IdLoc: Tok.getLocation());
1235	ConsumeToken(); // the identifier
1236
1237	TryConsumeToken(Expected: tok::ellipsis, Loc&: EllipsisLoc);
1238
1239	// If the next token signals the end of a template argument, then we have
1240	// a (possibly-dependent) template name that could be a template template
1241	// argument.
1242	TemplateTy Template;
1243	if (isEndOfTemplateArgument(Tok) &&
1244	Actions.ActOnTemplateName(S: getCurScope(), SS, TemplateKWLoc, Name,
1245	/*ObjectType=*/nullptr,
1246	/*EnteringContext=*/false, Template))
1247	Result = ParsedTemplateArgument(SS, Template, Name.StartLocation);
1248	}
1249	} else if (Tok.is(K: tok::identifier)) {
1250	// We may have a (non-dependent) template name.
1251	TemplateTy Template;
1252	UnqualifiedId Name;
1253	Name.setIdentifier(Id: Tok.getIdentifierInfo(), IdLoc: Tok.getLocation());
1254	ConsumeToken(); // the identifier
1255
1256	TryConsumeToken(Expected: tok::ellipsis, Loc&: EllipsisLoc);
1257
1258	if (isEndOfTemplateArgument(Tok)) {
1259	bool MemberOfUnknownSpecialization;
1260	TemplateNameKind TNK = Actions.isTemplateName(
1261	S: getCurScope(), SS,
1262	/*hasTemplateKeyword=*/false, Name,
1263	/*ObjectType=*/nullptr,
1264	/*EnteringContext=*/false, Template, MemberOfUnknownSpecialization);
1265	if (TNK == TNK_Dependent_template_name || TNK == TNK_Type_template) {
1266	// We have an id-expression that refers to a class template or
1267	// (C++0x) alias template.
1268	Result = ParsedTemplateArgument(SS, Template, Name.StartLocation);
1269	}
1270	}
1271	}
1272
1273	// If this is a pack expansion, build it as such.
1274	if (EllipsisLoc.isValid() && !Result.isInvalid())
1275	Result = Actions.ActOnPackExpansion(Arg: Result, EllipsisLoc);
1276
1277	return Result;
1278	}
1279
1280	ParsedTemplateArgument Parser::ParseTemplateArgument() {
1281	// C++ [temp.arg]p2:
1282	// In a template-argument, an ambiguity between a type-id and an
1283	// expression is resolved to a type-id, regardless of the form of
1284	// the corresponding template-parameter.
1285	//
1286	// Therefore, we initially try to parse a type-id - and isCXXTypeId might look
1287	// up and annotate an identifier as an id-expression during disambiguation,
1288	// so enter the appropriate context for a constant expression template
1289	// argument before trying to disambiguate.
1290
1291	EnterExpressionEvaluationContext EnterConstantEvaluated(
1292	Actions, Sema::ExpressionEvaluationContext::ConstantEvaluated,
1293	/*LambdaContextDecl=*/nullptr,
1294	/*ExprContext=*/Sema::ExpressionEvaluationContextRecord::EK_TemplateArgument);
1295	if (isCXXTypeId(Context: TentativeCXXTypeIdContext::AsTemplateArgument)) {
1296	TypeResult TypeArg = ParseTypeName(
1297	/*Range=*/nullptr, Context: DeclaratorContext::TemplateArg);
1298	return Actions.ActOnTemplateTypeArgument(ParsedType: TypeArg);
1299	}
1300
1301	// Try to parse a template template argument.
1302	{
1303	TentativeParsingAction TPA(*this);
1304
1305	ParsedTemplateArgument TemplateTemplateArgument
1306	= ParseTemplateTemplateArgument();
1307	if (!TemplateTemplateArgument.isInvalid()) {
1308	TPA.Commit();
1309	return TemplateTemplateArgument;
1310	}
1311
1312	// Revert this tentative parse to parse a non-type template argument.
1313	TPA.Revert();
1314	}
1315
1316	// Parse a non-type template argument.
1317	ExprResult ExprArg;
1318	SourceLocation Loc = Tok.getLocation();
1319	if (getLangOpts().CPlusPlus11 && Tok.is(K: tok::l_brace))
1320	ExprArg = ParseBraceInitializer();
1321	else
1322	ExprArg =
1323	ParseConstantExpressionInExprEvalContext(isTypeCast: TypeCastState::MaybeTypeCast);
1324	if (ExprArg.isInvalid() || !ExprArg.get()) {
1325	return ParsedTemplateArgument();
1326	}
1327
1328	return ParsedTemplateArgument(ParsedTemplateArgument::NonType,
1329	ExprArg.get(), Loc);
1330	}
1331
1332	bool Parser::ParseTemplateArgumentList(TemplateArgList &TemplateArgs,
1333	TemplateTy Template,
1334	SourceLocation OpenLoc) {
1335
1336	ColonProtectionRAIIObject ColonProtection(*this, false);
1337
1338	auto RunSignatureHelp = [&] {
1339	if (!Template)
1340	return QualType();
1341	CalledSignatureHelp = true;
1342	return Actions.CodeCompletion().ProduceTemplateArgumentSignatureHelp(
1343	Template, TemplateArgs, LAngleLoc: OpenLoc);
1344	};
1345
1346	do {
1347	PreferredType.enterFunctionArgument(Tok.getLocation(), RunSignatureHelp);
1348	ParsedTemplateArgument Arg = ParseTemplateArgument();
1349	SourceLocation EllipsisLoc;
1350	if (TryConsumeToken(Expected: tok::ellipsis, Loc&: EllipsisLoc))
1351	Arg = Actions.ActOnPackExpansion(Arg, EllipsisLoc);
1352
1353	if (Arg.isInvalid()) {
1354	if (PP.isCodeCompletionReached() && !CalledSignatureHelp)
1355	RunSignatureHelp();
1356	return true;
1357	}
1358
1359	// Save this template argument.
1360	TemplateArgs.push_back(Elt: Arg);
1361
1362	// If the next token is a comma, consume it and keep reading
1363	// arguments.
1364	} while (TryConsumeToken(Expected: tok::comma));
1365
1366	return false;
1367	}
1368
1369	Parser::DeclGroupPtrTy Parser::ParseExplicitInstantiation(
1370	DeclaratorContext Context, SourceLocation ExternLoc,
1371	SourceLocation TemplateLoc, SourceLocation &DeclEnd,
1372	ParsedAttributes &AccessAttrs, AccessSpecifier AS) {
1373	// This isn't really required here.
1374	ParsingDeclRAIIObject
1375	ParsingTemplateParams(*this, ParsingDeclRAIIObject::NoParent);
1376	ParsedTemplateInfo TemplateInfo(ExternLoc, TemplateLoc);
1377	return ParseDeclarationAfterTemplate(
1378	Context, TemplateInfo, DiagsFromTParams&: ParsingTemplateParams, DeclEnd, AccessAttrs, AS);
1379	}
1380
1381	SourceRange Parser::ParsedTemplateInfo::getSourceRange() const {
1382	if (TemplateParams)
1383	return getTemplateParamsRange(Params: TemplateParams->data(),
1384	NumParams: TemplateParams->size());
1385
1386	SourceRange R(TemplateLoc);
1387	if (ExternLoc.isValid())
1388	R.setBegin(ExternLoc);
1389	return R;
1390	}
1391
1392	void Parser::LateTemplateParserCallback(void *P, LateParsedTemplate &LPT) {
1393	((Parser *)P)->ParseLateTemplatedFuncDef(LPT);
1394	}
1395
1396	void Parser::ParseLateTemplatedFuncDef(LateParsedTemplate &LPT) {
1397	if (!LPT.D)
1398	return;
1399
1400	// Destroy TemplateIdAnnotations when we're done, if possible.
1401	DestroyTemplateIdAnnotationsRAIIObj CleanupRAII(*this);
1402
1403	// Get the FunctionDecl.
1404	FunctionDecl *FunD = LPT.D->getAsFunction();
1405	// Track template parameter depth.
1406	TemplateParameterDepthRAII CurTemplateDepthTracker(TemplateParameterDepth);
1407
1408	// To restore the context after late parsing.
1409	Sema::ContextRAII GlobalSavedContext(
1410	Actions, Actions.Context.getTranslationUnitDecl());
1411
1412	MultiParseScope Scopes(*this);
1413
1414	// Get the list of DeclContexts to reenter.
1415	SmallVector<DeclContext*, 4> DeclContextsToReenter;
1416	for (DeclContext *DC = FunD; DC && !DC->isTranslationUnit();
1417	DC = DC->getLexicalParent())
1418	DeclContextsToReenter.push_back(Elt: DC);
1419
1420	// Reenter scopes from outermost to innermost.
1421	for (DeclContext *DC : reverse(C&: DeclContextsToReenter)) {
1422	CurTemplateDepthTracker.addDepth(
1423	D: ReenterTemplateScopes(S&: Scopes, D: cast<Decl>(Val: DC)));
1424	Scopes.Enter(ScopeFlags: Scope::DeclScope);
1425	// We'll reenter the function context itself below.
1426	if (DC != FunD)
1427	Actions.PushDeclContext(S: Actions.getCurScope(), DC);
1428	}
1429
1430	// Parsing should occur with empty FP pragma stack and FP options used in the
1431	// point of the template definition.
1432	Sema::FpPragmaStackSaveRAII SavedStack(Actions);
1433	Actions.resetFPOptions(FPO: LPT.FPO);
1434
1435	assert(!LPT.Toks.empty() && "Empty body!");
1436
1437	// Append the current token at the end of the new token stream so that it
1438	// doesn't get lost.
1439	LPT.Toks.push_back(Elt: Tok);
1440	PP.EnterTokenStream(Toks: LPT.Toks, DisableMacroExpansion: true, /*IsReinject*/true);
1441
1442	// Consume the previously pushed token.
1443	ConsumeAnyToken(/*ConsumeCodeCompletionTok=*/true);
1444	assert(Tok.isOneOf(tok::l_brace, tok::colon, tok::kw_try) &&
1445	"Inline method not starting with '{', ':' or 'try'");
1446
1447	// Parse the method body. Function body parsing code is similar enough
1448	// to be re-used for method bodies as well.
1449	ParseScope FnScope(this, Scope::FnScope | Scope::DeclScope |
1450	Scope::CompoundStmtScope);
1451
1452	// Recreate the containing function DeclContext.
1453	Sema::ContextRAII FunctionSavedContext(Actions, FunD->getLexicalParent());
1454
1455	Actions.ActOnStartOfFunctionDef(getCurScope(), FunD);
1456
1457	if (Tok.is(K: tok::kw_try)) {
1458	ParseFunctionTryBlock(Decl: LPT.D, BodyScope&: FnScope);
1459	} else {
1460	if (Tok.is(K: tok::colon))
1461	ParseConstructorInitializer(ConstructorDecl: LPT.D);
1462	else
1463	Actions.ActOnDefaultCtorInitializers(CDtorDecl: LPT.D);
1464
1465	if (Tok.is(K: tok::l_brace)) {
1466	assert((!isa<FunctionTemplateDecl>(LPT.D) ||
1467	cast<FunctionTemplateDecl>(LPT.D)
1468	->getTemplateParameters()
1469	->getDepth() == TemplateParameterDepth - 1) &&
1470	"TemplateParameterDepth should be greater than the depth of "
1471	"current template being instantiated!");
1472	ParseFunctionStatementBody(Decl: LPT.D, BodyScope&: FnScope);
1473	Actions.UnmarkAsLateParsedTemplate(FD: FunD);
1474	} else
1475	Actions.ActOnFinishFunctionBody(Decl: LPT.D, Body: nullptr);
1476	}
1477	}
1478
1479	void Parser::LexTemplateFunctionForLateParsing(CachedTokens &Toks) {
1480	tok::TokenKind kind = Tok.getKind();
1481	if (!ConsumeAndStoreFunctionPrologue(Toks)) {
1482	// Consume everything up to (and including) the matching right brace.
1483	ConsumeAndStoreUntil(T1: tok::r_brace, Toks, /*StopAtSemi=*/false);
1484	}
1485
1486	// If we're in a function-try-block, we need to store all the catch blocks.
1487	if (kind == tok::kw_try) {
1488	while (Tok.is(K: tok::kw_catch)) {
1489	ConsumeAndStoreUntil(T1: tok::l_brace, Toks, /*StopAtSemi=*/false);
1490	ConsumeAndStoreUntil(T1: tok::r_brace, Toks, /*StopAtSemi=*/false);
1491	}
1492	}
1493	}
1494
1495	bool Parser::diagnoseUnknownTemplateId(ExprResult LHS, SourceLocation Less) {
1496	TentativeParsingAction TPA(*this);
1497	// FIXME: We could look at the token sequence in a lot more detail here.
1498	if (SkipUntil(T1: tok::greater, T2: tok::greatergreater, T3: tok::greatergreatergreater,
1499	Flags: StopAtSemi | StopBeforeMatch)) {
1500	TPA.Commit();
1501
1502	SourceLocation Greater;
1503	ParseGreaterThanInTemplateList(LAngleLoc: Less, RAngleLoc&: Greater, ConsumeLastToken: true, ObjCGenericList: false);
1504	Actions.diagnoseExprIntendedAsTemplateName(S: getCurScope(), TemplateName: LHS,
1505	Less, Greater);
1506	return true;
1507	}
1508
1509	// There's no matching '>' token, this probably isn't supposed to be
1510	// interpreted as a template-id. Parse it as an (ill-formed) comparison.
1511	TPA.Revert();
1512	return false;
1513	}
1514
1515	void Parser::checkPotentialAngleBracket(ExprResult &PotentialTemplateName) {
1516	assert(Tok.is(tok::less) && "not at a potential angle bracket");
1517
1518	bool DependentTemplateName = false;
1519	if (!Actions.mightBeIntendedToBeTemplateName(E: PotentialTemplateName,
1520	Dependent&: DependentTemplateName))
1521	return;
1522
1523	// OK, this might be a name that the user intended to be parsed as a
1524	// template-name, followed by a '<' token. Check for some easy cases.
1525
1526	// If we have potential_template<>, then it's supposed to be a template-name.
1527	if (NextToken().is(K: tok::greater) ||
1528	(getLangOpts().CPlusPlus11 &&
1529	NextToken().isOneOf(K1: tok::greatergreater, K2: tok::greatergreatergreater))) {
1530	SourceLocation Less = ConsumeToken();
1531	SourceLocation Greater;
1532	ParseGreaterThanInTemplateList(LAngleLoc: Less, RAngleLoc&: Greater, ConsumeLastToken: true, ObjCGenericList: false);
1533	Actions.diagnoseExprIntendedAsTemplateName(
1534	S: getCurScope(), TemplateName: PotentialTemplateName, Less, Greater);
1535	// FIXME: Perform error recovery.
1536	PotentialTemplateName = ExprError();
1537	return;
1538	}
1539
1540	// If we have 'potential_template<type-id', assume it's supposed to be a
1541	// template-name if there's a matching '>' later on.
1542	{
1543	// FIXME: Avoid the tentative parse when NextToken() can't begin a type.
1544	TentativeParsingAction TPA(*this);
1545	SourceLocation Less = ConsumeToken();
1546	if (isTypeIdUnambiguously() &&
1547	diagnoseUnknownTemplateId(LHS: PotentialTemplateName, Less)) {
1548	TPA.Commit();
1549	// FIXME: Perform error recovery.
1550	PotentialTemplateName = ExprError();
1551	return;
1552	}
1553	TPA.Revert();
1554	}
1555
1556	// Otherwise, remember that we saw this in case we see a potentially-matching
1557	// '>' token later on.
1558	AngleBracketTracker::Priority Priority =
1559	(DependentTemplateName ? AngleBracketTracker::DependentName
1560	: AngleBracketTracker::PotentialTypo) |
1561	(Tok.hasLeadingSpace() ? AngleBracketTracker::SpaceBeforeLess
1562	: AngleBracketTracker::NoSpaceBeforeLess);
1563	AngleBrackets.add(P&: *this, TemplateName: PotentialTemplateName.get(), LessLoc: Tok.getLocation(),
1564	Prio: Priority);
1565	}
1566
1567	bool Parser::checkPotentialAngleBracketDelimiter(
1568	const AngleBracketTracker::Loc &LAngle, const Token &OpToken) {
1569	// If a comma in an expression context is followed by a type that can be a
1570	// template argument and cannot be an expression, then this is ill-formed,
1571	// but might be intended to be part of a template-id.
1572	if (OpToken.is(K: tok::comma) && isTypeIdUnambiguously() &&
1573	diagnoseUnknownTemplateId(LHS: LAngle.TemplateName, Less: LAngle.LessLoc)) {
1574	AngleBrackets.clear(P&: *this);
1575	return true;
1576	}
1577
1578	// If a context that looks like a template-id is followed by '()', then
1579	// this is ill-formed, but might be intended to be a template-id
1580	// followed by '()'.
1581	if (OpToken.is(K: tok::greater) && Tok.is(K: tok::l_paren) &&
1582	NextToken().is(K: tok::r_paren)) {
1583	Actions.diagnoseExprIntendedAsTemplateName(
1584	S: getCurScope(), TemplateName: LAngle.TemplateName, Less: LAngle.LessLoc,
1585	Greater: OpToken.getLocation());
1586	AngleBrackets.clear(P&: *this);
1587	return true;
1588	}
1589
1590	// After a '>' (etc), we're no longer potentially in a construct that's
1591	// intended to be treated as a template-id.
1592	if (OpToken.is(K: tok::greater) ||
1593	(getLangOpts().CPlusPlus11 &&
1594	OpToken.isOneOf(K1: tok::greatergreater, K2: tok::greatergreatergreater)))
1595	AngleBrackets.clear(P&: *this);
1596	return false;
1597	}
1598