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/Parse/ParseDiagnostic.h"
17 #include "clang/Parse/Parser.h"
18 #include "clang/Parse/RAIIObjectsForParser.h"
19 #include "clang/Sema/DeclSpec.h"
20 #include "clang/Sema/ParsedTemplate.h"
21 #include "clang/Sema/Scope.h"
22 #include "llvm/Support/TimeProfiler.h"
23 using namespace clang;
24
25 /// Parse a template declaration, explicit instantiation, or
26 /// explicit specialization.
ParseDeclarationStartingWithTemplate(DeclaratorContext Context,SourceLocation & DeclEnd,ParsedAttributes & AccessAttrs,AccessSpecifier AS)27 Decl *Parser::ParseDeclarationStartingWithTemplate(
28 DeclaratorContext Context, SourceLocation &DeclEnd,
29 ParsedAttributes &AccessAttrs, AccessSpecifier AS) {
30 ObjCDeclContextSwitch ObjCDC(*this);
31
32 if (Tok.is(tok::kw_template) && NextToken().isNot(tok::less)) {
33 return ParseExplicitInstantiation(Context, SourceLocation(), ConsumeToken(),
34 DeclEnd, AccessAttrs, AS);
35 }
36 return ParseTemplateDeclarationOrSpecialization(Context, DeclEnd, AccessAttrs,
37 AS);
38 }
39
40 /// Parse a template declaration or an explicit specialization.
41 ///
42 /// Template declarations include one or more template parameter lists
43 /// and either the function or class template declaration. Explicit
44 /// specializations contain one or more 'template < >' prefixes
45 /// followed by a (possibly templated) declaration. Since the
46 /// syntactic form of both features is nearly identical, we parse all
47 /// of the template headers together and let semantic analysis sort
48 /// the declarations from the explicit specializations.
49 ///
50 /// template-declaration: [C++ temp]
51 /// 'export'[opt] 'template' '<' template-parameter-list '>' declaration
52 ///
53 /// template-declaration: [C++2a]
54 /// template-head declaration
55 /// template-head concept-definition
56 ///
57 /// TODO: requires-clause
58 /// template-head: [C++2a]
59 /// 'template' '<' template-parameter-list '>'
60 /// requires-clause[opt]
61 ///
62 /// explicit-specialization: [ C++ temp.expl.spec]
63 /// 'template' '<' '>' declaration
ParseTemplateDeclarationOrSpecialization(DeclaratorContext Context,SourceLocation & DeclEnd,ParsedAttributes & AccessAttrs,AccessSpecifier AS)64 Decl *Parser::ParseTemplateDeclarationOrSpecialization(
65 DeclaratorContext Context, SourceLocation &DeclEnd,
66 ParsedAttributes &AccessAttrs, AccessSpecifier AS) {
67 assert(Tok.isOneOf(tok::kw_export, tok::kw_template) &&
68 "Token does not start a template declaration.");
69
70 // Enter template-parameter scope.
71 ParseScope TemplateParmScope(this, Scope::TemplateParamScope);
72
73 // Tell the action that names should be checked in the context of
74 // the declaration to come.
75 ParsingDeclRAIIObject
76 ParsingTemplateParams(*this, ParsingDeclRAIIObject::NoParent);
77
78 // Parse multiple levels of template headers within this template
79 // parameter scope, e.g.,
80 //
81 // template<typename T>
82 // template<typename U>
83 // class A<T>::B { ... };
84 //
85 // We parse multiple levels non-recursively so that we can build a
86 // single data structure containing all of the template parameter
87 // lists to easily differentiate between the case above and:
88 //
89 // template<typename T>
90 // class A {
91 // template<typename U> class B;
92 // };
93 //
94 // In the first case, the action for declaring A<T>::B receives
95 // both template parameter lists. In the second case, the action for
96 // defining A<T>::B receives just the inner template parameter list
97 // (and retrieves the outer template parameter list from its
98 // context).
99 bool isSpecialization = true;
100 bool LastParamListWasEmpty = false;
101 TemplateParameterLists ParamLists;
102 TemplateParameterDepthRAII CurTemplateDepthTracker(TemplateParameterDepth);
103
104 do {
105 // Consume the 'export', if any.
106 SourceLocation ExportLoc;
107 TryConsumeToken(tok::kw_export, ExportLoc);
108
109 // Consume the 'template', which should be here.
110 SourceLocation TemplateLoc;
111 if (!TryConsumeToken(tok::kw_template, TemplateLoc)) {
112 Diag(Tok.getLocation(), diag::err_expected_template);
113 return nullptr;
114 }
115
116 // Parse the '<' template-parameter-list '>'
117 SourceLocation LAngleLoc, RAngleLoc;
118 SmallVector<NamedDecl*, 4> TemplateParams;
119 if (ParseTemplateParameters(CurTemplateDepthTracker.getDepth(),
120 TemplateParams, LAngleLoc, RAngleLoc)) {
121 // Skip until the semi-colon or a '}'.
122 SkipUntil(tok::r_brace, StopAtSemi | StopBeforeMatch);
123 TryConsumeToken(tok::semi);
124 return nullptr;
125 }
126
127 ExprResult OptionalRequiresClauseConstraintER;
128 if (!TemplateParams.empty()) {
129 isSpecialization = false;
130 ++CurTemplateDepthTracker;
131
132 if (TryConsumeToken(tok::kw_requires)) {
133 OptionalRequiresClauseConstraintER =
134 Actions.CorrectDelayedTyposInExpr(
135 ParseConstraintLogicalOrExpression(
136 /*IsTrailingRequiresClause=*/false));
137 if (!OptionalRequiresClauseConstraintER.isUsable()) {
138 // Skip until the semi-colon or a '}'.
139 SkipUntil(tok::r_brace, StopAtSemi | StopBeforeMatch);
140 TryConsumeToken(tok::semi);
141 return nullptr;
142 }
143 }
144 } else {
145 LastParamListWasEmpty = true;
146 }
147
148 ParamLists.push_back(Actions.ActOnTemplateParameterList(
149 CurTemplateDepthTracker.getDepth(), ExportLoc, TemplateLoc, LAngleLoc,
150 TemplateParams, RAngleLoc, OptionalRequiresClauseConstraintER.get()));
151 } while (Tok.isOneOf(tok::kw_export, tok::kw_template));
152
153 unsigned NewFlags = getCurScope()->getFlags() & ~Scope::TemplateParamScope;
154 ParseScopeFlags TemplateScopeFlags(this, NewFlags, isSpecialization);
155
156 // Parse the actual template declaration.
157 if (Tok.is(tok::kw_concept))
158 return ParseConceptDefinition(
159 ParsedTemplateInfo(&ParamLists, isSpecialization,
160 LastParamListWasEmpty),
161 DeclEnd);
162
163 return ParseSingleDeclarationAfterTemplate(
164 Context,
165 ParsedTemplateInfo(&ParamLists, isSpecialization, LastParamListWasEmpty),
166 ParsingTemplateParams, DeclEnd, AccessAttrs, AS);
167 }
168
169 /// Parse a single declaration that declares a template,
170 /// template specialization, or explicit instantiation of a template.
171 ///
172 /// \param DeclEnd will receive the source location of the last token
173 /// within this declaration.
174 ///
175 /// \param AS the access specifier associated with this
176 /// declaration. Will be AS_none for namespace-scope declarations.
177 ///
178 /// \returns the new declaration.
ParseSingleDeclarationAfterTemplate(DeclaratorContext Context,const ParsedTemplateInfo & TemplateInfo,ParsingDeclRAIIObject & DiagsFromTParams,SourceLocation & DeclEnd,ParsedAttributes & AccessAttrs,AccessSpecifier AS)179 Decl *Parser::ParseSingleDeclarationAfterTemplate(
180 DeclaratorContext Context, const ParsedTemplateInfo &TemplateInfo,
181 ParsingDeclRAIIObject &DiagsFromTParams, SourceLocation &DeclEnd,
182 ParsedAttributes &AccessAttrs, AccessSpecifier AS) {
183 assert(TemplateInfo.Kind != ParsedTemplateInfo::NonTemplate &&
184 "Template information required");
185
186 if (Tok.is(tok::kw_static_assert)) {
187 // A static_assert declaration may not be templated.
188 Diag(Tok.getLocation(), diag::err_templated_invalid_declaration)
189 << TemplateInfo.getSourceRange();
190 // Parse the static_assert declaration to improve error recovery.
191 return ParseStaticAssertDeclaration(DeclEnd);
192 }
193
194 if (Context == DeclaratorContext::MemberContext) {
195 // We are parsing a member template.
196 ParseCXXClassMemberDeclaration(AS, AccessAttrs, TemplateInfo,
197 &DiagsFromTParams);
198 return nullptr;
199 }
200
201 ParsedAttributesWithRange prefixAttrs(AttrFactory);
202 MaybeParseCXX11Attributes(prefixAttrs);
203
204 if (Tok.is(tok::kw_using)) {
205 auto usingDeclPtr = ParseUsingDirectiveOrDeclaration(Context, TemplateInfo, DeclEnd,
206 prefixAttrs);
207 if (!usingDeclPtr || !usingDeclPtr.get().isSingleDecl())
208 return nullptr;
209 return usingDeclPtr.get().getSingleDecl();
210 }
211
212 // Parse the declaration specifiers, stealing any diagnostics from
213 // the template parameters.
214 ParsingDeclSpec DS(*this, &DiagsFromTParams);
215
216 ParseDeclarationSpecifiers(DS, TemplateInfo, AS,
217 getDeclSpecContextFromDeclaratorContext(Context));
218
219 if (Tok.is(tok::semi)) {
220 ProhibitAttributes(prefixAttrs);
221 DeclEnd = ConsumeToken();
222 RecordDecl *AnonRecord = nullptr;
223 Decl *Decl = Actions.ParsedFreeStandingDeclSpec(
224 getCurScope(), AS, DS,
225 TemplateInfo.TemplateParams ? *TemplateInfo.TemplateParams
226 : MultiTemplateParamsArg(),
227 TemplateInfo.Kind == ParsedTemplateInfo::ExplicitInstantiation,
228 AnonRecord);
229 assert(!AnonRecord &&
230 "Anonymous unions/structs should not be valid with template");
231 DS.complete(Decl);
232 return Decl;
233 }
234
235 // Move the attributes from the prefix into the DS.
236 if (TemplateInfo.Kind == ParsedTemplateInfo::ExplicitInstantiation)
237 ProhibitAttributes(prefixAttrs);
238 else
239 DS.takeAttributesFrom(prefixAttrs);
240
241 // Parse the declarator.
242 ParsingDeclarator DeclaratorInfo(*this, DS, (DeclaratorContext)Context);
243 if (TemplateInfo.TemplateParams)
244 DeclaratorInfo.setTemplateParameterLists(*TemplateInfo.TemplateParams);
245 ParseDeclarator(DeclaratorInfo);
246 // Error parsing the declarator?
247 if (!DeclaratorInfo.hasName()) {
248 // If so, skip until the semi-colon or a }.
249 SkipUntil(tok::r_brace, StopAtSemi | StopBeforeMatch);
250 if (Tok.is(tok::semi))
251 ConsumeToken();
252 return nullptr;
253 }
254
255 llvm::TimeTraceScope TimeScope("ParseTemplate", [&]() {
256 return DeclaratorInfo.getIdentifier() != nullptr
257 ? DeclaratorInfo.getIdentifier()->getName()
258 : "<unknown>";
259 });
260
261 LateParsedAttrList LateParsedAttrs(true);
262 if (DeclaratorInfo.isFunctionDeclarator()) {
263 if (Tok.is(tok::kw_requires))
264 ParseTrailingRequiresClause(DeclaratorInfo);
265
266 MaybeParseGNUAttributes(DeclaratorInfo, &LateParsedAttrs);
267 }
268
269 if (DeclaratorInfo.isFunctionDeclarator() &&
270 isStartOfFunctionDefinition(DeclaratorInfo)) {
271
272 // Function definitions are only allowed at file scope and in C++ classes.
273 // The C++ inline method definition case is handled elsewhere, so we only
274 // need to handle the file scope definition case.
275 if (Context != DeclaratorContext::FileContext) {
276 Diag(Tok, diag::err_function_definition_not_allowed);
277 SkipMalformedDecl();
278 return nullptr;
279 }
280
281 if (DS.getStorageClassSpec() == DeclSpec::SCS_typedef) {
282 // Recover by ignoring the 'typedef'. This was probably supposed to be
283 // the 'typename' keyword, which we should have already suggested adding
284 // if it's appropriate.
285 Diag(DS.getStorageClassSpecLoc(), diag::err_function_declared_typedef)
286 << FixItHint::CreateRemoval(DS.getStorageClassSpecLoc());
287 DS.ClearStorageClassSpecs();
288 }
289
290 if (TemplateInfo.Kind == ParsedTemplateInfo::ExplicitInstantiation) {
291 if (DeclaratorInfo.getName().getKind() !=
292 UnqualifiedIdKind::IK_TemplateId) {
293 // If the declarator-id is not a template-id, issue a diagnostic and
294 // recover by ignoring the 'template' keyword.
295 Diag(Tok, diag::err_template_defn_explicit_instantiation) << 0;
296 return ParseFunctionDefinition(DeclaratorInfo, ParsedTemplateInfo(),
297 &LateParsedAttrs);
298 } else {
299 SourceLocation LAngleLoc
300 = PP.getLocForEndOfToken(TemplateInfo.TemplateLoc);
301 Diag(DeclaratorInfo.getIdentifierLoc(),
302 diag::err_explicit_instantiation_with_definition)
303 << SourceRange(TemplateInfo.TemplateLoc)
304 << FixItHint::CreateInsertion(LAngleLoc, "<>");
305
306 // Recover as if it were an explicit specialization.
307 TemplateParameterLists FakedParamLists;
308 FakedParamLists.push_back(Actions.ActOnTemplateParameterList(
309 0, SourceLocation(), TemplateInfo.TemplateLoc, LAngleLoc, None,
310 LAngleLoc, nullptr));
311
312 return ParseFunctionDefinition(
313 DeclaratorInfo, ParsedTemplateInfo(&FakedParamLists,
314 /*isSpecialization=*/true,
315 /*lastParameterListWasEmpty=*/true),
316 &LateParsedAttrs);
317 }
318 }
319 return ParseFunctionDefinition(DeclaratorInfo, TemplateInfo,
320 &LateParsedAttrs);
321 }
322
323 // Parse this declaration.
324 Decl *ThisDecl = ParseDeclarationAfterDeclarator(DeclaratorInfo,
325 TemplateInfo);
326
327 if (Tok.is(tok::comma)) {
328 Diag(Tok, diag::err_multiple_template_declarators)
329 << (int)TemplateInfo.Kind;
330 SkipUntil(tok::semi);
331 return ThisDecl;
332 }
333
334 // Eat the semi colon after the declaration.
335 ExpectAndConsumeSemi(diag::err_expected_semi_declaration);
336 if (LateParsedAttrs.size() > 0)
337 ParseLexedAttributeList(LateParsedAttrs, ThisDecl, true, false);
338 DeclaratorInfo.complete(ThisDecl);
339 return ThisDecl;
340 }
341
342 /// \brief Parse a single declaration that declares a concept.
343 ///
344 /// \param DeclEnd will receive the source location of the last token
345 /// within this declaration.
346 ///
347 /// \returns the new declaration.
348 Decl *
ParseConceptDefinition(const ParsedTemplateInfo & TemplateInfo,SourceLocation & DeclEnd)349 Parser::ParseConceptDefinition(const ParsedTemplateInfo &TemplateInfo,
350 SourceLocation &DeclEnd) {
351 assert(TemplateInfo.Kind != ParsedTemplateInfo::NonTemplate &&
352 "Template information required");
353 assert(Tok.is(tok::kw_concept) &&
354 "ParseConceptDefinition must be called when at a 'concept' keyword");
355
356 ConsumeToken(); // Consume 'concept'
357
358 SourceLocation BoolKWLoc;
359 if (TryConsumeToken(tok::kw_bool, BoolKWLoc))
360 Diag(Tok.getLocation(), diag::ext_concept_legacy_bool_keyword) <<
361 FixItHint::CreateRemoval(SourceLocation(BoolKWLoc));
362
363 DiagnoseAndSkipCXX11Attributes();
364
365 CXXScopeSpec SS;
366 if (ParseOptionalCXXScopeSpecifier(SS, ParsedType(),
367 /*EnteringContext=*/false, /*MayBePseudoDestructor=*/nullptr,
368 /*IsTypename=*/false, /*LastII=*/nullptr, /*OnlyNamespace=*/true) ||
369 SS.isInvalid()) {
370 SkipUntil(tok::semi);
371 return nullptr;
372 }
373
374 if (SS.isNotEmpty())
375 Diag(SS.getBeginLoc(),
376 diag::err_concept_definition_not_identifier);
377
378 UnqualifiedId Result;
379 if (ParseUnqualifiedId(SS, /*EnteringContext=*/false,
380 /*AllowDestructorName=*/false,
381 /*AllowConstructorName=*/false,
382 /*AllowDeductionGuide=*/false,
383 /*ObjectType=*/ParsedType(), /*TemplateKWLoc=*/nullptr,
384 Result)) {
385 SkipUntil(tok::semi);
386 return nullptr;
387 }
388
389 if (Result.getKind() != UnqualifiedIdKind::IK_Identifier) {
390 Diag(Result.getBeginLoc(), diag::err_concept_definition_not_identifier);
391 SkipUntil(tok::semi);
392 return nullptr;
393 }
394
395 IdentifierInfo *Id = Result.Identifier;
396 SourceLocation IdLoc = Result.getBeginLoc();
397
398 DiagnoseAndSkipCXX11Attributes();
399
400 if (!TryConsumeToken(tok::equal)) {
401 Diag(Tok.getLocation(), diag::err_expected) << tok::equal;
402 SkipUntil(tok::semi);
403 return nullptr;
404 }
405
406 ExprResult ConstraintExprResult =
407 Actions.CorrectDelayedTyposInExpr(ParseConstraintExpression());
408 if (ConstraintExprResult.isInvalid()) {
409 SkipUntil(tok::semi);
410 return nullptr;
411 }
412
413 DeclEnd = Tok.getLocation();
414 ExpectAndConsumeSemi(diag::err_expected_semi_declaration);
415 Expr *ConstraintExpr = ConstraintExprResult.get();
416 return Actions.ActOnConceptDefinition(getCurScope(),
417 *TemplateInfo.TemplateParams,
418 Id, IdLoc, ConstraintExpr);
419 }
420
421 /// ParseTemplateParameters - Parses a template-parameter-list enclosed in
422 /// angle brackets. Depth is the depth of this template-parameter-list, which
423 /// is the number of template headers directly enclosing this template header.
424 /// TemplateParams is the current list of template parameters we're building.
425 /// The template parameter we parse will be added to this list. LAngleLoc and
426 /// RAngleLoc will receive the positions of the '<' and '>', respectively,
427 /// that enclose this template parameter list.
428 ///
429 /// \returns true if an error occurred, false otherwise.
ParseTemplateParameters(unsigned Depth,SmallVectorImpl<NamedDecl * > & TemplateParams,SourceLocation & LAngleLoc,SourceLocation & RAngleLoc)430 bool Parser::ParseTemplateParameters(
431 unsigned Depth, SmallVectorImpl<NamedDecl *> &TemplateParams,
432 SourceLocation &LAngleLoc, SourceLocation &RAngleLoc) {
433 // Get the template parameter list.
434 if (!TryConsumeToken(tok::less, LAngleLoc)) {
435 Diag(Tok.getLocation(), diag::err_expected_less_after) << "template";
436 return true;
437 }
438
439 // Try to parse the template parameter list.
440 bool Failed = false;
441 if (!Tok.is(tok::greater) && !Tok.is(tok::greatergreater))
442 Failed = ParseTemplateParameterList(Depth, TemplateParams);
443
444 if (Tok.is(tok::greatergreater)) {
445 // No diagnostic required here: a template-parameter-list can only be
446 // followed by a declaration or, for a template template parameter, the
447 // 'class' keyword. Therefore, the second '>' will be diagnosed later.
448 // This matters for elegant diagnosis of:
449 // template<template<typename>> struct S;
450 Tok.setKind(tok::greater);
451 RAngleLoc = Tok.getLocation();
452 Tok.setLocation(Tok.getLocation().getLocWithOffset(1));
453 } else if (!TryConsumeToken(tok::greater, RAngleLoc) && Failed) {
454 Diag(Tok.getLocation(), diag::err_expected) << tok::greater;
455 return true;
456 }
457 return false;
458 }
459
460 /// ParseTemplateParameterList - Parse a template parameter list. If
461 /// the parsing fails badly (i.e., closing bracket was left out), this
462 /// will try to put the token stream in a reasonable position (closing
463 /// a statement, etc.) and return false.
464 ///
465 /// template-parameter-list: [C++ temp]
466 /// template-parameter
467 /// template-parameter-list ',' template-parameter
468 bool
ParseTemplateParameterList(const unsigned Depth,SmallVectorImpl<NamedDecl * > & TemplateParams)469 Parser::ParseTemplateParameterList(const unsigned Depth,
470 SmallVectorImpl<NamedDecl*> &TemplateParams) {
471 while (1) {
472
473 if (NamedDecl *TmpParam
474 = ParseTemplateParameter(Depth, TemplateParams.size())) {
475 TemplateParams.push_back(TmpParam);
476 } else {
477 // If we failed to parse a template parameter, skip until we find
478 // a comma or closing brace.
479 SkipUntil(tok::comma, tok::greater, tok::greatergreater,
480 StopAtSemi | StopBeforeMatch);
481 }
482
483 // Did we find a comma or the end of the template parameter list?
484 if (Tok.is(tok::comma)) {
485 ConsumeToken();
486 } else if (Tok.isOneOf(tok::greater, tok::greatergreater)) {
487 // Don't consume this... that's done by template parser.
488 break;
489 } else {
490 // Somebody probably forgot to close the template. Skip ahead and
491 // try to get out of the expression. This error is currently
492 // subsumed by whatever goes on in ParseTemplateParameter.
493 Diag(Tok.getLocation(), diag::err_expected_comma_greater);
494 SkipUntil(tok::comma, tok::greater, tok::greatergreater,
495 StopAtSemi | StopBeforeMatch);
496 return false;
497 }
498 }
499 return true;
500 }
501
502 /// Determine whether the parser is at the start of a template
503 /// type parameter.
isStartOfTemplateTypeParameter()504 Parser::TPResult Parser::isStartOfTemplateTypeParameter() {
505 if (Tok.is(tok::kw_class)) {
506 // "class" may be the start of an elaborated-type-specifier or a
507 // type-parameter. Per C++ [temp.param]p3, we prefer the type-parameter.
508 switch (NextToken().getKind()) {
509 case tok::equal:
510 case tok::comma:
511 case tok::greater:
512 case tok::greatergreater:
513 case tok::ellipsis:
514 return TPResult::True;
515
516 case tok::identifier:
517 // This may be either a type-parameter or an elaborated-type-specifier.
518 // We have to look further.
519 break;
520
521 default:
522 return TPResult::False;
523 }
524
525 switch (GetLookAheadToken(2).getKind()) {
526 case tok::equal:
527 case tok::comma:
528 case tok::greater:
529 case tok::greatergreater:
530 return TPResult::True;
531
532 default:
533 return TPResult::False;
534 }
535 }
536
537 if (TryAnnotateTypeConstraint())
538 return TPResult::Error;
539
540 if (isTypeConstraintAnnotation() &&
541 // Next token might be 'auto' or 'decltype', indicating that this
542 // type-constraint is in fact part of a placeholder-type-specifier of a
543 // non-type template parameter.
544 !GetLookAheadToken(Tok.is(tok::annot_cxxscope) ? 2 : 1)
545 .isOneOf(tok::kw_auto, tok::kw_decltype))
546 return TPResult::True;
547
548 // 'typedef' is a reasonably-common typo/thinko for 'typename', and is
549 // ill-formed otherwise.
550 if (Tok.isNot(tok::kw_typename) && Tok.isNot(tok::kw_typedef))
551 return TPResult::False;
552
553 // C++ [temp.param]p2:
554 // There is no semantic difference between class and typename in a
555 // template-parameter. typename followed by an unqualified-id
556 // names a template type parameter. typename followed by a
557 // qualified-id denotes the type in a non-type
558 // parameter-declaration.
559 Token Next = NextToken();
560
561 // If we have an identifier, skip over it.
562 if (Next.getKind() == tok::identifier)
563 Next = GetLookAheadToken(2);
564
565 switch (Next.getKind()) {
566 case tok::equal:
567 case tok::comma:
568 case tok::greater:
569 case tok::greatergreater:
570 case tok::ellipsis:
571 return TPResult::True;
572
573 case tok::kw_typename:
574 case tok::kw_typedef:
575 case tok::kw_class:
576 // These indicate that a comma was missed after a type parameter, not that
577 // we have found a non-type parameter.
578 return TPResult::True;
579
580 default:
581 return TPResult::False;
582 }
583 }
584
585 /// ParseTemplateParameter - Parse a template-parameter (C++ [temp.param]).
586 ///
587 /// template-parameter: [C++ temp.param]
588 /// type-parameter
589 /// parameter-declaration
590 ///
591 /// type-parameter: (See below)
592 /// type-parameter-key ...[opt] identifier[opt]
593 /// type-parameter-key identifier[opt] = type-id
594 /// (C++2a) type-constraint ...[opt] identifier[opt]
595 /// (C++2a) type-constraint identifier[opt] = type-id
596 /// 'template' '<' template-parameter-list '>' type-parameter-key
597 /// ...[opt] identifier[opt]
598 /// 'template' '<' template-parameter-list '>' type-parameter-key
599 /// identifier[opt] '=' id-expression
600 ///
601 /// type-parameter-key:
602 /// class
603 /// typename
604 ///
ParseTemplateParameter(unsigned Depth,unsigned Position)605 NamedDecl *Parser::ParseTemplateParameter(unsigned Depth, unsigned Position) {
606
607 switch (isStartOfTemplateTypeParameter()) {
608 case TPResult::True:
609 // Is there just a typo in the input code? ('typedef' instead of
610 // 'typename')
611 if (Tok.is(tok::kw_typedef)) {
612 Diag(Tok.getLocation(), diag::err_expected_template_parameter);
613
614 Diag(Tok.getLocation(), diag::note_meant_to_use_typename)
615 << FixItHint::CreateReplacement(CharSourceRange::getCharRange(
616 Tok.getLocation(),
617 Tok.getEndLoc()),
618 "typename");
619
620 Tok.setKind(tok::kw_typename);
621 }
622
623 return ParseTypeParameter(Depth, Position);
624 case TPResult::False:
625 break;
626
627 case TPResult::Error: {
628 // We return an invalid parameter as opposed to null to avoid having bogus
629 // diagnostics about an empty template parameter list.
630 // FIXME: Fix ParseTemplateParameterList to better handle nullptr results
631 // from here.
632 // Return a NTTP as if there was an error in a scope specifier, the user
633 // probably meant to write the type of a NTTP.
634 DeclSpec DS(getAttrFactory());
635 DS.SetTypeSpecError();
636 Declarator D(DS, DeclaratorContext::TemplateParamContext);
637 D.SetIdentifier(nullptr, Tok.getLocation());
638 D.setInvalidType(true);
639 NamedDecl *ErrorParam = Actions.ActOnNonTypeTemplateParameter(
640 getCurScope(), D, Depth, Position, /*EqualLoc=*/SourceLocation(),
641 /*DefaultArg=*/nullptr);
642 ErrorParam->setInvalidDecl(true);
643 SkipUntil(tok::comma, tok::greater, tok::greatergreater,
644 StopAtSemi | StopBeforeMatch);
645 return ErrorParam;
646 }
647
648 case TPResult::Ambiguous:
649 llvm_unreachable("template param classification can't be ambiguous");
650 }
651
652 if (Tok.is(tok::kw_template))
653 return ParseTemplateTemplateParameter(Depth, Position);
654
655 // If it's none of the above, then it must be a parameter declaration.
656 // NOTE: This will pick up errors in the closure of the template parameter
657 // list (e.g., template < ; Check here to implement >> style closures.
658 return ParseNonTypeTemplateParameter(Depth, Position);
659 }
660
661 /// Check whether the current token is a template-id annotation denoting a
662 /// type-constraint.
isTypeConstraintAnnotation()663 bool Parser::isTypeConstraintAnnotation() {
664 const Token &T = Tok.is(tok::annot_cxxscope) ? NextToken() : Tok;
665 if (T.isNot(tok::annot_template_id))
666 return false;
667 const auto *ExistingAnnot =
668 static_cast<TemplateIdAnnotation *>(T.getAnnotationValue());
669 return ExistingAnnot->Kind == TNK_Concept_template;
670 }
671
672 /// Try parsing a type-constraint at the current location.
673 ///
674 /// type-constraint:
675 /// nested-name-specifier[opt] concept-name
676 /// nested-name-specifier[opt] concept-name
677 /// '<' template-argument-list[opt] '>'[opt]
678 ///
679 /// \returns true if an error occurred, and false otherwise.
TryAnnotateTypeConstraint()680 bool Parser::TryAnnotateTypeConstraint() {
681 if (!getLangOpts().CPlusPlus2a)
682 return false;
683 CXXScopeSpec SS;
684 bool WasScopeAnnotation = Tok.is(tok::annot_cxxscope);
685 if (ParseOptionalCXXScopeSpecifier(
686 SS, ParsedType(),
687 /*EnteringContext=*/false,
688 /*MayBePseudoDestructor=*/nullptr,
689 // If this is not a type-constraint, then
690 // this scope-spec is part of the typename
691 // of a non-type template parameter
692 /*IsTypename=*/true, /*LastII=*/nullptr,
693 // We won't find concepts in
694 // non-namespaces anyway, so might as well
695 // parse this correctly for possible type
696 // names.
697 /*OnlyNamespace=*/false))
698 return true;
699
700 if (Tok.is(tok::identifier)) {
701 UnqualifiedId PossibleConceptName;
702 PossibleConceptName.setIdentifier(Tok.getIdentifierInfo(),
703 Tok.getLocation());
704
705 TemplateTy PossibleConcept;
706 bool MemberOfUnknownSpecialization = false;
707 auto TNK = Actions.isTemplateName(getCurScope(), SS,
708 /*hasTemplateKeyword=*/false,
709 PossibleConceptName,
710 /*ObjectType=*/ParsedType(),
711 /*EnteringContext=*/false,
712 PossibleConcept,
713 MemberOfUnknownSpecialization,
714 /*Disambiguation=*/true);
715 if (MemberOfUnknownSpecialization || !PossibleConcept ||
716 TNK != TNK_Concept_template) {
717 if (SS.isNotEmpty())
718 AnnotateScopeToken(SS, !WasScopeAnnotation);
719 return false;
720 }
721
722 // At this point we're sure we're dealing with a constrained parameter. It
723 // may or may not have a template parameter list following the concept
724 // name.
725 if (AnnotateTemplateIdToken(PossibleConcept, TNK, SS,
726 /*TemplateKWLoc=*/SourceLocation(),
727 PossibleConceptName,
728 /*AllowTypeAnnotation=*/false,
729 /*TypeConstraint=*/true))
730 return true;
731 }
732
733 if (SS.isNotEmpty())
734 AnnotateScopeToken(SS, !WasScopeAnnotation);
735 return false;
736 }
737
738 /// ParseTypeParameter - Parse a template type parameter (C++ [temp.param]).
739 /// Other kinds of template parameters are parsed in
740 /// ParseTemplateTemplateParameter and ParseNonTypeTemplateParameter.
741 ///
742 /// type-parameter: [C++ temp.param]
743 /// 'class' ...[opt][C++0x] identifier[opt]
744 /// 'class' identifier[opt] '=' type-id
745 /// 'typename' ...[opt][C++0x] identifier[opt]
746 /// 'typename' identifier[opt] '=' type-id
ParseTypeParameter(unsigned Depth,unsigned Position)747 NamedDecl *Parser::ParseTypeParameter(unsigned Depth, unsigned Position) {
748 assert((Tok.isOneOf(tok::kw_class, tok::kw_typename) ||
749 isTypeConstraintAnnotation()) &&
750 "A type-parameter starts with 'class', 'typename' or a "
751 "type-constraint");
752
753 CXXScopeSpec TypeConstraintSS;
754 TemplateIdAnnotation *TypeConstraint = nullptr;
755 bool TypenameKeyword = false;
756 SourceLocation KeyLoc;
757 ParseOptionalCXXScopeSpecifier(TypeConstraintSS, nullptr,
758 /*EnteringContext*/ false);
759 if (Tok.is(tok::annot_template_id)) {
760 // Consume the 'type-constraint'.
761 TypeConstraint =
762 static_cast<TemplateIdAnnotation *>(Tok.getAnnotationValue());
763 assert(TypeConstraint->Kind == TNK_Concept_template &&
764 "stray non-concept template-id annotation");
765 KeyLoc = ConsumeAnnotationToken();
766 } else {
767 assert(TypeConstraintSS.isEmpty() &&
768 "expected type constraint after scope specifier");
769
770 // Consume the 'class' or 'typename' keyword.
771 TypenameKeyword = Tok.is(tok::kw_typename);
772 KeyLoc = ConsumeToken();
773 }
774
775 // Grab the ellipsis (if given).
776 SourceLocation EllipsisLoc;
777 if (TryConsumeToken(tok::ellipsis, EllipsisLoc)) {
778 Diag(EllipsisLoc,
779 getLangOpts().CPlusPlus11
780 ? diag::warn_cxx98_compat_variadic_templates
781 : diag::ext_variadic_templates);
782 }
783
784 // Grab the template parameter name (if given)
785 SourceLocation NameLoc = Tok.getLocation();
786 IdentifierInfo *ParamName = nullptr;
787 if (Tok.is(tok::identifier)) {
788 ParamName = Tok.getIdentifierInfo();
789 ConsumeToken();
790 } else if (Tok.isOneOf(tok::equal, tok::comma, tok::greater,
791 tok::greatergreater)) {
792 // Unnamed template parameter. Don't have to do anything here, just
793 // don't consume this token.
794 } else {
795 Diag(Tok.getLocation(), diag::err_expected) << tok::identifier;
796 return nullptr;
797 }
798
799 // Recover from misplaced ellipsis.
800 bool AlreadyHasEllipsis = EllipsisLoc.isValid();
801 if (TryConsumeToken(tok::ellipsis, EllipsisLoc))
802 DiagnoseMisplacedEllipsis(EllipsisLoc, NameLoc, AlreadyHasEllipsis, true);
803
804 // Grab a default argument (if available).
805 // Per C++0x [basic.scope.pdecl]p9, we parse the default argument before
806 // we introduce the type parameter into the local scope.
807 SourceLocation EqualLoc;
808 ParsedType DefaultArg;
809 if (TryConsumeToken(tok::equal, EqualLoc))
810 DefaultArg = ParseTypeName(/*Range=*/nullptr,
811 DeclaratorContext::TemplateTypeArgContext)
812 .get();
813
814 NamedDecl *NewDecl = Actions.ActOnTypeParameter(getCurScope(),
815 TypenameKeyword, EllipsisLoc,
816 KeyLoc, ParamName, NameLoc,
817 Depth, Position, EqualLoc,
818 DefaultArg,
819 TypeConstraint != nullptr);
820
821 if (TypeConstraint) {
822 Actions.ActOnTypeConstraint(TypeConstraintSS, TypeConstraint,
823 cast<TemplateTypeParmDecl>(NewDecl),
824 EllipsisLoc);
825 }
826
827 return NewDecl;
828 }
829
830 /// ParseTemplateTemplateParameter - Handle the parsing of template
831 /// template parameters.
832 ///
833 /// type-parameter: [C++ temp.param]
834 /// 'template' '<' template-parameter-list '>' type-parameter-key
835 /// ...[opt] identifier[opt]
836 /// 'template' '<' template-parameter-list '>' type-parameter-key
837 /// identifier[opt] = id-expression
838 /// type-parameter-key:
839 /// 'class'
840 /// 'typename' [C++1z]
841 NamedDecl *
ParseTemplateTemplateParameter(unsigned Depth,unsigned Position)842 Parser::ParseTemplateTemplateParameter(unsigned Depth, unsigned Position) {
843 assert(Tok.is(tok::kw_template) && "Expected 'template' keyword");
844
845 // Handle the template <...> part.
846 SourceLocation TemplateLoc = ConsumeToken();
847 SmallVector<NamedDecl*,8> TemplateParams;
848 SourceLocation LAngleLoc, RAngleLoc;
849 {
850 ParseScope TemplateParmScope(this, Scope::TemplateParamScope);
851 if (ParseTemplateParameters(Depth + 1, TemplateParams, LAngleLoc,
852 RAngleLoc)) {
853 return nullptr;
854 }
855 }
856
857 // Provide an ExtWarn if the C++1z feature of using 'typename' here is used.
858 // Generate a meaningful error if the user forgot to put class before the
859 // identifier, comma, or greater. Provide a fixit if the identifier, comma,
860 // or greater appear immediately or after 'struct'. In the latter case,
861 // replace the keyword with 'class'.
862 if (!TryConsumeToken(tok::kw_class)) {
863 bool Replace = Tok.isOneOf(tok::kw_typename, tok::kw_struct);
864 const Token &Next = Tok.is(tok::kw_struct) ? NextToken() : Tok;
865 if (Tok.is(tok::kw_typename)) {
866 Diag(Tok.getLocation(),
867 getLangOpts().CPlusPlus17
868 ? diag::warn_cxx14_compat_template_template_param_typename
869 : diag::ext_template_template_param_typename)
870 << (!getLangOpts().CPlusPlus17
871 ? FixItHint::CreateReplacement(Tok.getLocation(), "class")
872 : FixItHint());
873 } else if (Next.isOneOf(tok::identifier, tok::comma, tok::greater,
874 tok::greatergreater, tok::ellipsis)) {
875 Diag(Tok.getLocation(), diag::err_class_on_template_template_param)
876 << (Replace ? FixItHint::CreateReplacement(Tok.getLocation(), "class")
877 : FixItHint::CreateInsertion(Tok.getLocation(), "class "));
878 } else
879 Diag(Tok.getLocation(), diag::err_class_on_template_template_param);
880
881 if (Replace)
882 ConsumeToken();
883 }
884
885 // Parse the ellipsis, if given.
886 SourceLocation EllipsisLoc;
887 if (TryConsumeToken(tok::ellipsis, EllipsisLoc))
888 Diag(EllipsisLoc,
889 getLangOpts().CPlusPlus11
890 ? diag::warn_cxx98_compat_variadic_templates
891 : diag::ext_variadic_templates);
892
893 // Get the identifier, if given.
894 SourceLocation NameLoc = Tok.getLocation();
895 IdentifierInfo *ParamName = nullptr;
896 if (Tok.is(tok::identifier)) {
897 ParamName = Tok.getIdentifierInfo();
898 ConsumeToken();
899 } else if (Tok.isOneOf(tok::equal, tok::comma, tok::greater,
900 tok::greatergreater)) {
901 // Unnamed template parameter. Don't have to do anything here, just
902 // don't consume this token.
903 } else {
904 Diag(Tok.getLocation(), diag::err_expected) << tok::identifier;
905 return nullptr;
906 }
907
908 // Recover from misplaced ellipsis.
909 bool AlreadyHasEllipsis = EllipsisLoc.isValid();
910 if (TryConsumeToken(tok::ellipsis, EllipsisLoc))
911 DiagnoseMisplacedEllipsis(EllipsisLoc, NameLoc, AlreadyHasEllipsis, true);
912
913 TemplateParameterList *ParamList =
914 Actions.ActOnTemplateParameterList(Depth, SourceLocation(),
915 TemplateLoc, LAngleLoc,
916 TemplateParams,
917 RAngleLoc, nullptr);
918
919 // Grab a default argument (if available).
920 // Per C++0x [basic.scope.pdecl]p9, we parse the default argument before
921 // we introduce the template parameter into the local scope.
922 SourceLocation EqualLoc;
923 ParsedTemplateArgument DefaultArg;
924 if (TryConsumeToken(tok::equal, EqualLoc)) {
925 DefaultArg = ParseTemplateTemplateArgument();
926 if (DefaultArg.isInvalid()) {
927 Diag(Tok.getLocation(),
928 diag::err_default_template_template_parameter_not_template);
929 SkipUntil(tok::comma, tok::greater, tok::greatergreater,
930 StopAtSemi | StopBeforeMatch);
931 }
932 }
933
934 return Actions.ActOnTemplateTemplateParameter(getCurScope(), TemplateLoc,
935 ParamList, EllipsisLoc,
936 ParamName, NameLoc, Depth,
937 Position, EqualLoc, DefaultArg);
938 }
939
940 /// ParseNonTypeTemplateParameter - Handle the parsing of non-type
941 /// template parameters (e.g., in "template<int Size> class array;").
942 ///
943 /// template-parameter:
944 /// ...
945 /// parameter-declaration
946 NamedDecl *
ParseNonTypeTemplateParameter(unsigned Depth,unsigned Position)947 Parser::ParseNonTypeTemplateParameter(unsigned Depth, unsigned Position) {
948 // Parse the declaration-specifiers (i.e., the type).
949 // FIXME: The type should probably be restricted in some way... Not all
950 // declarators (parts of declarators?) are accepted for parameters.
951 DeclSpec DS(AttrFactory);
952 ParseDeclarationSpecifiers(DS, ParsedTemplateInfo(), AS_none,
953 DeclSpecContext::DSC_template_param);
954
955 // Parse this as a typename.
956 Declarator ParamDecl(DS, DeclaratorContext::TemplateParamContext);
957 ParseDeclarator(ParamDecl);
958 if (DS.getTypeSpecType() == DeclSpec::TST_unspecified) {
959 Diag(Tok.getLocation(), diag::err_expected_template_parameter);
960 return nullptr;
961 }
962
963 // Recover from misplaced ellipsis.
964 SourceLocation EllipsisLoc;
965 if (TryConsumeToken(tok::ellipsis, EllipsisLoc))
966 DiagnoseMisplacedEllipsisInDeclarator(EllipsisLoc, ParamDecl);
967
968 // If there is a default value, parse it.
969 // Per C++0x [basic.scope.pdecl]p9, we parse the default argument before
970 // we introduce the template parameter into the local scope.
971 SourceLocation EqualLoc;
972 ExprResult DefaultArg;
973 if (TryConsumeToken(tok::equal, EqualLoc)) {
974 // C++ [temp.param]p15:
975 // When parsing a default template-argument for a non-type
976 // template-parameter, the first non-nested > is taken as the
977 // end of the template-parameter-list rather than a greater-than
978 // operator.
979 GreaterThanIsOperatorScope G(GreaterThanIsOperator, false);
980 EnterExpressionEvaluationContext ConstantEvaluated(
981 Actions, Sema::ExpressionEvaluationContext::ConstantEvaluated);
982
983 DefaultArg = Actions.CorrectDelayedTyposInExpr(ParseAssignmentExpression());
984 if (DefaultArg.isInvalid())
985 SkipUntil(tok::comma, tok::greater, StopAtSemi | StopBeforeMatch);
986 }
987
988 // Create the parameter.
989 return Actions.ActOnNonTypeTemplateParameter(getCurScope(), ParamDecl,
990 Depth, Position, EqualLoc,
991 DefaultArg.get());
992 }
993
DiagnoseMisplacedEllipsis(SourceLocation EllipsisLoc,SourceLocation CorrectLoc,bool AlreadyHasEllipsis,bool IdentifierHasName)994 void Parser::DiagnoseMisplacedEllipsis(SourceLocation EllipsisLoc,
995 SourceLocation CorrectLoc,
996 bool AlreadyHasEllipsis,
997 bool IdentifierHasName) {
998 FixItHint Insertion;
999 if (!AlreadyHasEllipsis)
1000 Insertion = FixItHint::CreateInsertion(CorrectLoc, "...");
1001 Diag(EllipsisLoc, diag::err_misplaced_ellipsis_in_declaration)
1002 << FixItHint::CreateRemoval(EllipsisLoc) << Insertion
1003 << !IdentifierHasName;
1004 }
1005
DiagnoseMisplacedEllipsisInDeclarator(SourceLocation EllipsisLoc,Declarator & D)1006 void Parser::DiagnoseMisplacedEllipsisInDeclarator(SourceLocation EllipsisLoc,
1007 Declarator &D) {
1008 assert(EllipsisLoc.isValid());
1009 bool AlreadyHasEllipsis = D.getEllipsisLoc().isValid();
1010 if (!AlreadyHasEllipsis)
1011 D.setEllipsisLoc(EllipsisLoc);
1012 DiagnoseMisplacedEllipsis(EllipsisLoc, D.getIdentifierLoc(),
1013 AlreadyHasEllipsis, D.hasName());
1014 }
1015
1016 /// Parses a '>' at the end of a template list.
1017 ///
1018 /// If this function encounters '>>', '>>>', '>=', or '>>=', it tries
1019 /// to determine if these tokens were supposed to be a '>' followed by
1020 /// '>', '>>', '>=', or '>='. It emits an appropriate diagnostic if necessary.
1021 ///
1022 /// \param RAngleLoc the location of the consumed '>'.
1023 ///
1024 /// \param ConsumeLastToken if true, the '>' is consumed.
1025 ///
1026 /// \param ObjCGenericList if true, this is the '>' closing an Objective-C
1027 /// type parameter or type argument list, rather than a C++ template parameter
1028 /// or argument list.
1029 ///
1030 /// \returns true, if current token does not start with '>', false otherwise.
ParseGreaterThanInTemplateList(SourceLocation & RAngleLoc,bool ConsumeLastToken,bool ObjCGenericList)1031 bool Parser::ParseGreaterThanInTemplateList(SourceLocation &RAngleLoc,
1032 bool ConsumeLastToken,
1033 bool ObjCGenericList) {
1034 // What will be left once we've consumed the '>'.
1035 tok::TokenKind RemainingToken;
1036 const char *ReplacementStr = "> >";
1037 bool MergeWithNextToken = false;
1038
1039 switch (Tok.getKind()) {
1040 default:
1041 Diag(Tok.getLocation(), diag::err_expected) << tok::greater;
1042 return true;
1043
1044 case tok::greater:
1045 // Determine the location of the '>' token. Only consume this token
1046 // if the caller asked us to.
1047 RAngleLoc = Tok.getLocation();
1048 if (ConsumeLastToken)
1049 ConsumeToken();
1050 return false;
1051
1052 case tok::greatergreater:
1053 RemainingToken = tok::greater;
1054 break;
1055
1056 case tok::greatergreatergreater:
1057 RemainingToken = tok::greatergreater;
1058 break;
1059
1060 case tok::greaterequal:
1061 RemainingToken = tok::equal;
1062 ReplacementStr = "> =";
1063
1064 // Join two adjacent '=' tokens into one, for cases like:
1065 // void (*p)() = f<int>;
1066 // return f<int>==p;
1067 if (NextToken().is(tok::equal) &&
1068 areTokensAdjacent(Tok, NextToken())) {
1069 RemainingToken = tok::equalequal;
1070 MergeWithNextToken = true;
1071 }
1072 break;
1073
1074 case tok::greatergreaterequal:
1075 RemainingToken = tok::greaterequal;
1076 break;
1077 }
1078
1079 // This template-id is terminated by a token that starts with a '>'.
1080 // Outside C++11 and Objective-C, this is now error recovery.
1081 //
1082 // C++11 allows this when the token is '>>', and in CUDA + C++11 mode, we
1083 // extend that treatment to also apply to the '>>>' token.
1084 //
1085 // Objective-C allows this in its type parameter / argument lists.
1086
1087 SourceLocation TokBeforeGreaterLoc = PrevTokLocation;
1088 SourceLocation TokLoc = Tok.getLocation();
1089 Token Next = NextToken();
1090
1091 // Whether splitting the current token after the '>' would undesirably result
1092 // in the remaining token pasting with the token after it. This excludes the
1093 // MergeWithNextToken cases, which we've already handled.
1094 bool PreventMergeWithNextToken =
1095 (RemainingToken == tok::greater ||
1096 RemainingToken == tok::greatergreater) &&
1097 (Next.isOneOf(tok::greater, tok::greatergreater,
1098 tok::greatergreatergreater, tok::equal, tok::greaterequal,
1099 tok::greatergreaterequal, tok::equalequal)) &&
1100 areTokensAdjacent(Tok, Next);
1101
1102 // Diagnose this situation as appropriate.
1103 if (!ObjCGenericList) {
1104 // The source range of the replaced token(s).
1105 CharSourceRange ReplacementRange = CharSourceRange::getCharRange(
1106 TokLoc, Lexer::AdvanceToTokenCharacter(TokLoc, 2, PP.getSourceManager(),
1107 getLangOpts()));
1108
1109 // A hint to put a space between the '>>'s. In order to make the hint as
1110 // clear as possible, we include the characters either side of the space in
1111 // the replacement, rather than just inserting a space at SecondCharLoc.
1112 FixItHint Hint1 = FixItHint::CreateReplacement(ReplacementRange,
1113 ReplacementStr);
1114
1115 // A hint to put another space after the token, if it would otherwise be
1116 // lexed differently.
1117 FixItHint Hint2;
1118 if (PreventMergeWithNextToken)
1119 Hint2 = FixItHint::CreateInsertion(Next.getLocation(), " ");
1120
1121 unsigned DiagId = diag::err_two_right_angle_brackets_need_space;
1122 if (getLangOpts().CPlusPlus11 &&
1123 (Tok.is(tok::greatergreater) || Tok.is(tok::greatergreatergreater)))
1124 DiagId = diag::warn_cxx98_compat_two_right_angle_brackets;
1125 else if (Tok.is(tok::greaterequal))
1126 DiagId = diag::err_right_angle_bracket_equal_needs_space;
1127 Diag(TokLoc, DiagId) << Hint1 << Hint2;
1128 }
1129
1130 // Find the "length" of the resulting '>' token. This is not always 1, as it
1131 // can contain escaped newlines.
1132 unsigned GreaterLength = Lexer::getTokenPrefixLength(
1133 TokLoc, 1, PP.getSourceManager(), getLangOpts());
1134
1135 // Annotate the source buffer to indicate that we split the token after the
1136 // '>'. This allows us to properly find the end of, and extract the spelling
1137 // of, the '>' token later.
1138 RAngleLoc = PP.SplitToken(TokLoc, GreaterLength);
1139
1140 // Strip the initial '>' from the token.
1141 bool CachingTokens = PP.IsPreviousCachedToken(Tok);
1142
1143 Token Greater = Tok;
1144 Greater.setLocation(RAngleLoc);
1145 Greater.setKind(tok::greater);
1146 Greater.setLength(GreaterLength);
1147
1148 unsigned OldLength = Tok.getLength();
1149 if (MergeWithNextToken) {
1150 ConsumeToken();
1151 OldLength += Tok.getLength();
1152 }
1153
1154 Tok.setKind(RemainingToken);
1155 Tok.setLength(OldLength - GreaterLength);
1156
1157 // Split the second token if lexing it normally would lex a different token
1158 // (eg, the fifth token in 'A<B>>>' should re-lex as '>', not '>>').
1159 SourceLocation AfterGreaterLoc = TokLoc.getLocWithOffset(GreaterLength);
1160 if (PreventMergeWithNextToken)
1161 AfterGreaterLoc = PP.SplitToken(AfterGreaterLoc, Tok.getLength());
1162 Tok.setLocation(AfterGreaterLoc);
1163
1164 // Update the token cache to match what we just did if necessary.
1165 if (CachingTokens) {
1166 // If the previous cached token is being merged, delete it.
1167 if (MergeWithNextToken)
1168 PP.ReplacePreviousCachedToken({});
1169
1170 if (ConsumeLastToken)
1171 PP.ReplacePreviousCachedToken({Greater, Tok});
1172 else
1173 PP.ReplacePreviousCachedToken({Greater});
1174 }
1175
1176 if (ConsumeLastToken) {
1177 PrevTokLocation = RAngleLoc;
1178 } else {
1179 PrevTokLocation = TokBeforeGreaterLoc;
1180 PP.EnterToken(Tok, /*IsReinject=*/true);
1181 Tok = Greater;
1182 }
1183
1184 return false;
1185 }
1186
1187
1188 /// Parses a template-id that after the template name has
1189 /// already been parsed.
1190 ///
1191 /// This routine takes care of parsing the enclosed template argument
1192 /// list ('<' template-parameter-list [opt] '>') and placing the
1193 /// results into a form that can be transferred to semantic analysis.
1194 ///
1195 /// \param ConsumeLastToken if true, then we will consume the last
1196 /// token that forms the template-id. Otherwise, we will leave the
1197 /// last token in the stream (e.g., so that it can be replaced with an
1198 /// annotation token).
1199 bool
ParseTemplateIdAfterTemplateName(bool ConsumeLastToken,SourceLocation & LAngleLoc,TemplateArgList & TemplateArgs,SourceLocation & RAngleLoc)1200 Parser::ParseTemplateIdAfterTemplateName(bool ConsumeLastToken,
1201 SourceLocation &LAngleLoc,
1202 TemplateArgList &TemplateArgs,
1203 SourceLocation &RAngleLoc) {
1204 assert(Tok.is(tok::less) && "Must have already parsed the template-name");
1205
1206 // Consume the '<'.
1207 LAngleLoc = ConsumeToken();
1208
1209 // Parse the optional template-argument-list.
1210 bool Invalid = false;
1211 {
1212 GreaterThanIsOperatorScope G(GreaterThanIsOperator, false);
1213 if (!Tok.isOneOf(tok::greater, tok::greatergreater,
1214 tok::greatergreatergreater, tok::greaterequal,
1215 tok::greatergreaterequal))
1216 Invalid = ParseTemplateArgumentList(TemplateArgs);
1217
1218 if (Invalid) {
1219 // Try to find the closing '>'.
1220 if (ConsumeLastToken)
1221 SkipUntil(tok::greater, StopAtSemi);
1222 else
1223 SkipUntil(tok::greater, StopAtSemi | StopBeforeMatch);
1224 return true;
1225 }
1226 }
1227
1228 return ParseGreaterThanInTemplateList(RAngleLoc, ConsumeLastToken,
1229 /*ObjCGenericList=*/false);
1230 }
1231
1232 /// Replace the tokens that form a simple-template-id with an
1233 /// annotation token containing the complete template-id.
1234 ///
1235 /// The first token in the stream must be the name of a template that
1236 /// is followed by a '<'. This routine will parse the complete
1237 /// simple-template-id and replace the tokens with a single annotation
1238 /// token with one of two different kinds: if the template-id names a
1239 /// type (and \p AllowTypeAnnotation is true), the annotation token is
1240 /// a type annotation that includes the optional nested-name-specifier
1241 /// (\p SS). Otherwise, the annotation token is a template-id
1242 /// annotation that does not include the optional
1243 /// nested-name-specifier.
1244 ///
1245 /// \param Template the declaration of the template named by the first
1246 /// token (an identifier), as returned from \c Action::isTemplateName().
1247 ///
1248 /// \param TNK the kind of template that \p Template
1249 /// refers to, as returned from \c Action::isTemplateName().
1250 ///
1251 /// \param SS if non-NULL, the nested-name-specifier that precedes
1252 /// this template name.
1253 ///
1254 /// \param TemplateKWLoc if valid, specifies that this template-id
1255 /// annotation was preceded by the 'template' keyword and gives the
1256 /// location of that keyword. If invalid (the default), then this
1257 /// template-id was not preceded by a 'template' keyword.
1258 ///
1259 /// \param AllowTypeAnnotation if true (the default), then a
1260 /// simple-template-id that refers to a class template, template
1261 /// template parameter, or other template that produces a type will be
1262 /// replaced with a type annotation token. Otherwise, the
1263 /// simple-template-id is always replaced with a template-id
1264 /// annotation token.
1265 ///
1266 /// \param TypeConstraint if true, then this is actually a type-constraint,
1267 /// meaning that the template argument list can be omitted (and the template in
1268 /// question must be a concept).
1269 ///
1270 /// If an unrecoverable parse error occurs and no annotation token can be
1271 /// formed, this function returns true.
1272 ///
AnnotateTemplateIdToken(TemplateTy Template,TemplateNameKind TNK,CXXScopeSpec & SS,SourceLocation TemplateKWLoc,UnqualifiedId & TemplateName,bool AllowTypeAnnotation,bool TypeConstraint)1273 bool Parser::AnnotateTemplateIdToken(TemplateTy Template, TemplateNameKind TNK,
1274 CXXScopeSpec &SS,
1275 SourceLocation TemplateKWLoc,
1276 UnqualifiedId &TemplateName,
1277 bool AllowTypeAnnotation,
1278 bool TypeConstraint) {
1279 assert(getLangOpts().CPlusPlus && "Can only annotate template-ids in C++");
1280 assert(Template && (Tok.is(tok::less) || TypeConstraint) &&
1281 "Parser isn't at the beginning of a template-id");
1282 assert(!(TypeConstraint && AllowTypeAnnotation) && "type-constraint can't be "
1283 "a type annotation");
1284 assert((!TypeConstraint || TNK == TNK_Concept_template) && "type-constraint "
1285 "must accompany a concept name");
1286
1287 // Consume the template-name.
1288 SourceLocation TemplateNameLoc = TemplateName.getSourceRange().getBegin();
1289
1290 // Parse the enclosed template argument list.
1291 SourceLocation LAngleLoc, RAngleLoc;
1292 TemplateArgList TemplateArgs;
1293 if (!TypeConstraint || Tok.is(tok::less)) {
1294 bool Invalid = ParseTemplateIdAfterTemplateName(false, LAngleLoc,
1295 TemplateArgs,
1296 RAngleLoc);
1297
1298 if (Invalid) {
1299 // If we failed to parse the template ID but skipped ahead to a >, we're not
1300 // going to be able to form a token annotation. Eat the '>' if present.
1301 TryConsumeToken(tok::greater);
1302 // FIXME: Annotate the token stream so we don't produce the same errors
1303 // again if we're doing this annotation as part of a tentative parse.
1304 return true;
1305 }
1306 }
1307
1308 ASTTemplateArgsPtr TemplateArgsPtr(TemplateArgs);
1309
1310 // Build the annotation token.
1311 if (TNK == TNK_Type_template && AllowTypeAnnotation) {
1312 TypeResult Type = Actions.ActOnTemplateIdType(
1313 getCurScope(), SS, TemplateKWLoc, Template, TemplateName.Identifier,
1314 TemplateNameLoc, LAngleLoc, TemplateArgsPtr, RAngleLoc);
1315 if (Type.isInvalid()) {
1316 // If we failed to parse the template ID but skipped ahead to a >, we're
1317 // not going to be able to form a token annotation. Eat the '>' if
1318 // present.
1319 TryConsumeToken(tok::greater);
1320 // FIXME: Annotate the token stream so we don't produce the same errors
1321 // again if we're doing this annotation as part of a tentative parse.
1322 return true;
1323 }
1324
1325 Tok.setKind(tok::annot_typename);
1326 setTypeAnnotation(Tok, Type.get());
1327 if (SS.isNotEmpty())
1328 Tok.setLocation(SS.getBeginLoc());
1329 else if (TemplateKWLoc.isValid())
1330 Tok.setLocation(TemplateKWLoc);
1331 else
1332 Tok.setLocation(TemplateNameLoc);
1333 } else {
1334 // Build a template-id annotation token that can be processed
1335 // later.
1336 Tok.setKind(tok::annot_template_id);
1337
1338 IdentifierInfo *TemplateII =
1339 TemplateName.getKind() == UnqualifiedIdKind::IK_Identifier
1340 ? TemplateName.Identifier
1341 : nullptr;
1342
1343 OverloadedOperatorKind OpKind =
1344 TemplateName.getKind() == UnqualifiedIdKind::IK_Identifier
1345 ? OO_None
1346 : TemplateName.OperatorFunctionId.Operator;
1347
1348 TemplateIdAnnotation *TemplateId = TemplateIdAnnotation::Create(
1349 TemplateKWLoc, TemplateNameLoc, TemplateII, OpKind, Template, TNK,
1350 LAngleLoc, RAngleLoc, TemplateArgs, TemplateIds);
1351
1352 Tok.setAnnotationValue(TemplateId);
1353 if (TemplateKWLoc.isValid())
1354 Tok.setLocation(TemplateKWLoc);
1355 else
1356 Tok.setLocation(TemplateNameLoc);
1357 }
1358
1359 // Common fields for the annotation token
1360 Tok.setAnnotationEndLoc(RAngleLoc);
1361
1362 // In case the tokens were cached, have Preprocessor replace them with the
1363 // annotation token.
1364 PP.AnnotateCachedTokens(Tok);
1365 return false;
1366 }
1367
1368 /// Replaces a template-id annotation token with a type
1369 /// annotation token.
1370 ///
1371 /// If there was a failure when forming the type from the template-id,
1372 /// a type annotation token will still be created, but will have a
1373 /// NULL type pointer to signify an error.
1374 ///
1375 /// \param SS The scope specifier appearing before the template-id, if any.
1376 ///
1377 /// \param IsClassName Is this template-id appearing in a context where we
1378 /// know it names a class, such as in an elaborated-type-specifier or
1379 /// base-specifier? ('typename' and 'template' are unneeded and disallowed
1380 /// in those contexts.)
AnnotateTemplateIdTokenAsType(CXXScopeSpec & SS,bool IsClassName)1381 void Parser::AnnotateTemplateIdTokenAsType(CXXScopeSpec &SS,
1382 bool IsClassName) {
1383 assert(Tok.is(tok::annot_template_id) && "Requires template-id tokens");
1384
1385 TemplateIdAnnotation *TemplateId = takeTemplateIdAnnotation(Tok);
1386 assert((TemplateId->Kind == TNK_Type_template ||
1387 TemplateId->Kind == TNK_Dependent_template_name ||
1388 TemplateId->Kind == TNK_Undeclared_template) &&
1389 "Only works for type and dependent templates");
1390
1391 ASTTemplateArgsPtr TemplateArgsPtr(TemplateId->getTemplateArgs(),
1392 TemplateId->NumArgs);
1393
1394 TypeResult Type
1395 = Actions.ActOnTemplateIdType(getCurScope(),
1396 SS,
1397 TemplateId->TemplateKWLoc,
1398 TemplateId->Template,
1399 TemplateId->Name,
1400 TemplateId->TemplateNameLoc,
1401 TemplateId->LAngleLoc,
1402 TemplateArgsPtr,
1403 TemplateId->RAngleLoc,
1404 /*IsCtorOrDtorName*/false,
1405 IsClassName);
1406 // Create the new "type" annotation token.
1407 Tok.setKind(tok::annot_typename);
1408 setTypeAnnotation(Tok, Type.isInvalid() ? nullptr : Type.get());
1409 if (SS.isNotEmpty()) // it was a C++ qualified type name.
1410 Tok.setLocation(SS.getBeginLoc());
1411 // End location stays the same
1412
1413 // Replace the template-id annotation token, and possible the scope-specifier
1414 // that precedes it, with the typename annotation token.
1415 PP.AnnotateCachedTokens(Tok);
1416 }
1417
1418 /// Determine whether the given token can end a template argument.
isEndOfTemplateArgument(Token Tok)1419 static bool isEndOfTemplateArgument(Token Tok) {
1420 return Tok.isOneOf(tok::comma, tok::greater, tok::greatergreater);
1421 }
1422
1423 /// Parse a C++ template template argument.
ParseTemplateTemplateArgument()1424 ParsedTemplateArgument Parser::ParseTemplateTemplateArgument() {
1425 if (!Tok.is(tok::identifier) && !Tok.is(tok::coloncolon) &&
1426 !Tok.is(tok::annot_cxxscope))
1427 return ParsedTemplateArgument();
1428
1429 // C++0x [temp.arg.template]p1:
1430 // A template-argument for a template template-parameter shall be the name
1431 // of a class template or an alias template, expressed as id-expression.
1432 //
1433 // We parse an id-expression that refers to a class template or alias
1434 // template. The grammar we parse is:
1435 //
1436 // nested-name-specifier[opt] template[opt] identifier ...[opt]
1437 //
1438 // followed by a token that terminates a template argument, such as ',',
1439 // '>', or (in some cases) '>>'.
1440 CXXScopeSpec SS; // nested-name-specifier, if present
1441 ParseOptionalCXXScopeSpecifier(SS, nullptr,
1442 /*EnteringContext=*/false);
1443
1444 ParsedTemplateArgument Result;
1445 SourceLocation EllipsisLoc;
1446 if (SS.isSet() && Tok.is(tok::kw_template)) {
1447 // Parse the optional 'template' keyword following the
1448 // nested-name-specifier.
1449 SourceLocation TemplateKWLoc = ConsumeToken();
1450
1451 if (Tok.is(tok::identifier)) {
1452 // We appear to have a dependent template name.
1453 UnqualifiedId Name;
1454 Name.setIdentifier(Tok.getIdentifierInfo(), Tok.getLocation());
1455 ConsumeToken(); // the identifier
1456
1457 TryConsumeToken(tok::ellipsis, EllipsisLoc);
1458
1459 // If the next token signals the end of a template argument,
1460 // then we have a dependent template name that could be a template
1461 // template argument.
1462 TemplateTy Template;
1463 if (isEndOfTemplateArgument(Tok) &&
1464 Actions.ActOnDependentTemplateName(
1465 getCurScope(), SS, TemplateKWLoc, Name,
1466 /*ObjectType=*/nullptr,
1467 /*EnteringContext=*/false, Template))
1468 Result = ParsedTemplateArgument(SS, Template, Name.StartLocation);
1469 }
1470 } else if (Tok.is(tok::identifier)) {
1471 // We may have a (non-dependent) template name.
1472 TemplateTy Template;
1473 UnqualifiedId Name;
1474 Name.setIdentifier(Tok.getIdentifierInfo(), Tok.getLocation());
1475 ConsumeToken(); // the identifier
1476
1477 TryConsumeToken(tok::ellipsis, EllipsisLoc);
1478
1479 if (isEndOfTemplateArgument(Tok)) {
1480 bool MemberOfUnknownSpecialization;
1481 TemplateNameKind TNK = Actions.isTemplateName(
1482 getCurScope(), SS,
1483 /*hasTemplateKeyword=*/false, Name,
1484 /*ObjectType=*/nullptr,
1485 /*EnteringContext=*/false, Template, MemberOfUnknownSpecialization);
1486 if (TNK == TNK_Dependent_template_name || TNK == TNK_Type_template) {
1487 // We have an id-expression that refers to a class template or
1488 // (C++0x) alias template.
1489 Result = ParsedTemplateArgument(SS, Template, Name.StartLocation);
1490 }
1491 }
1492 }
1493
1494 // If this is a pack expansion, build it as such.
1495 if (EllipsisLoc.isValid() && !Result.isInvalid())
1496 Result = Actions.ActOnPackExpansion(Result, EllipsisLoc);
1497
1498 return Result;
1499 }
1500
1501 /// ParseTemplateArgument - Parse a C++ template argument (C++ [temp.names]).
1502 ///
1503 /// template-argument: [C++ 14.2]
1504 /// constant-expression
1505 /// type-id
1506 /// id-expression
ParseTemplateArgument()1507 ParsedTemplateArgument Parser::ParseTemplateArgument() {
1508 // C++ [temp.arg]p2:
1509 // In a template-argument, an ambiguity between a type-id and an
1510 // expression is resolved to a type-id, regardless of the form of
1511 // the corresponding template-parameter.
1512 //
1513 // Therefore, we initially try to parse a type-id - and isCXXTypeId might look
1514 // up and annotate an identifier as an id-expression during disambiguation,
1515 // so enter the appropriate context for a constant expression template
1516 // argument before trying to disambiguate.
1517
1518 EnterExpressionEvaluationContext EnterConstantEvaluated(
1519 Actions, Sema::ExpressionEvaluationContext::ConstantEvaluated,
1520 /*LambdaContextDecl=*/nullptr,
1521 /*ExprContext=*/Sema::ExpressionEvaluationContextRecord::EK_TemplateArgument);
1522 if (isCXXTypeId(TypeIdAsTemplateArgument)) {
1523 TypeResult TypeArg = ParseTypeName(
1524 /*Range=*/nullptr, DeclaratorContext::TemplateArgContext);
1525 return Actions.ActOnTemplateTypeArgument(TypeArg);
1526 }
1527
1528 // Try to parse a template template argument.
1529 {
1530 TentativeParsingAction TPA(*this);
1531
1532 ParsedTemplateArgument TemplateTemplateArgument
1533 = ParseTemplateTemplateArgument();
1534 if (!TemplateTemplateArgument.isInvalid()) {
1535 TPA.Commit();
1536 return TemplateTemplateArgument;
1537 }
1538
1539 // Revert this tentative parse to parse a non-type template argument.
1540 TPA.Revert();
1541 }
1542
1543 // Parse a non-type template argument.
1544 SourceLocation Loc = Tok.getLocation();
1545 ExprResult ExprArg = ParseConstantExpressionInExprEvalContext(MaybeTypeCast);
1546 if (ExprArg.isInvalid() || !ExprArg.get()) {
1547 return ParsedTemplateArgument();
1548 }
1549
1550 return ParsedTemplateArgument(ParsedTemplateArgument::NonType,
1551 ExprArg.get(), Loc);
1552 }
1553
1554 /// ParseTemplateArgumentList - Parse a C++ template-argument-list
1555 /// (C++ [temp.names]). Returns true if there was an error.
1556 ///
1557 /// template-argument-list: [C++ 14.2]
1558 /// template-argument
1559 /// template-argument-list ',' template-argument
1560 bool
ParseTemplateArgumentList(TemplateArgList & TemplateArgs)1561 Parser::ParseTemplateArgumentList(TemplateArgList &TemplateArgs) {
1562
1563 ColonProtectionRAIIObject ColonProtection(*this, false);
1564
1565 do {
1566 ParsedTemplateArgument Arg = ParseTemplateArgument();
1567 SourceLocation EllipsisLoc;
1568 if (TryConsumeToken(tok::ellipsis, EllipsisLoc))
1569 Arg = Actions.ActOnPackExpansion(Arg, EllipsisLoc);
1570
1571 if (Arg.isInvalid()) {
1572 SkipUntil(tok::comma, tok::greater, StopAtSemi | StopBeforeMatch);
1573 return true;
1574 }
1575
1576 // Save this template argument.
1577 TemplateArgs.push_back(Arg);
1578
1579 // If the next token is a comma, consume it and keep reading
1580 // arguments.
1581 } while (TryConsumeToken(tok::comma));
1582
1583 return false;
1584 }
1585
1586 /// Parse a C++ explicit template instantiation
1587 /// (C++ [temp.explicit]).
1588 ///
1589 /// explicit-instantiation:
1590 /// 'extern' [opt] 'template' declaration
1591 ///
1592 /// Note that the 'extern' is a GNU extension and C++11 feature.
ParseExplicitInstantiation(DeclaratorContext Context,SourceLocation ExternLoc,SourceLocation TemplateLoc,SourceLocation & DeclEnd,ParsedAttributes & AccessAttrs,AccessSpecifier AS)1593 Decl *Parser::ParseExplicitInstantiation(DeclaratorContext Context,
1594 SourceLocation ExternLoc,
1595 SourceLocation TemplateLoc,
1596 SourceLocation &DeclEnd,
1597 ParsedAttributes &AccessAttrs,
1598 AccessSpecifier AS) {
1599 // This isn't really required here.
1600 ParsingDeclRAIIObject
1601 ParsingTemplateParams(*this, ParsingDeclRAIIObject::NoParent);
1602
1603 return ParseSingleDeclarationAfterTemplate(
1604 Context, ParsedTemplateInfo(ExternLoc, TemplateLoc),
1605 ParsingTemplateParams, DeclEnd, AccessAttrs, AS);
1606 }
1607
getSourceRange() const1608 SourceRange Parser::ParsedTemplateInfo::getSourceRange() const {
1609 if (TemplateParams)
1610 return getTemplateParamsRange(TemplateParams->data(),
1611 TemplateParams->size());
1612
1613 SourceRange R(TemplateLoc);
1614 if (ExternLoc.isValid())
1615 R.setBegin(ExternLoc);
1616 return R;
1617 }
1618
LateTemplateParserCallback(void * P,LateParsedTemplate & LPT)1619 void Parser::LateTemplateParserCallback(void *P, LateParsedTemplate &LPT) {
1620 ((Parser *)P)->ParseLateTemplatedFuncDef(LPT);
1621 }
1622
1623 /// Late parse a C++ function template in Microsoft mode.
ParseLateTemplatedFuncDef(LateParsedTemplate & LPT)1624 void Parser::ParseLateTemplatedFuncDef(LateParsedTemplate &LPT) {
1625 if (!LPT.D)
1626 return;
1627
1628 // Get the FunctionDecl.
1629 FunctionDecl *FunD = LPT.D->getAsFunction();
1630 // Track template parameter depth.
1631 TemplateParameterDepthRAII CurTemplateDepthTracker(TemplateParameterDepth);
1632
1633 // To restore the context after late parsing.
1634 Sema::ContextRAII GlobalSavedContext(
1635 Actions, Actions.Context.getTranslationUnitDecl());
1636
1637 SmallVector<ParseScope*, 4> TemplateParamScopeStack;
1638
1639 // Get the list of DeclContexts to reenter. For inline methods, we only want
1640 // to push the DeclContext of the outermost class. This matches the way the
1641 // parser normally parses bodies of inline methods when the outermost class is
1642 // complete.
1643 struct ContainingDC {
1644 ContainingDC(DeclContext *DC, bool ShouldPush) : Pair(DC, ShouldPush) {}
1645 llvm::PointerIntPair<DeclContext *, 1, bool> Pair;
1646 DeclContext *getDC() { return Pair.getPointer(); }
1647 bool shouldPushDC() { return Pair.getInt(); }
1648 };
1649 SmallVector<ContainingDC, 4> DeclContextsToReenter;
1650 DeclContext *DD = FunD;
1651 DeclContext *NextContaining = Actions.getContainingDC(DD);
1652 while (DD && !DD->isTranslationUnit()) {
1653 bool ShouldPush = DD == NextContaining;
1654 DeclContextsToReenter.push_back({DD, ShouldPush});
1655 if (ShouldPush)
1656 NextContaining = Actions.getContainingDC(DD);
1657 DD = DD->getLexicalParent();
1658 }
1659
1660 // Reenter template scopes from outermost to innermost.
1661 for (ContainingDC CDC : reverse(DeclContextsToReenter)) {
1662 TemplateParamScopeStack.push_back(
1663 new ParseScope(this, Scope::TemplateParamScope));
1664 unsigned NumParamLists = Actions.ActOnReenterTemplateScope(
1665 getCurScope(), cast<Decl>(CDC.getDC()));
1666 CurTemplateDepthTracker.addDepth(NumParamLists);
1667 if (CDC.shouldPushDC()) {
1668 TemplateParamScopeStack.push_back(new ParseScope(this, Scope::DeclScope));
1669 Actions.PushDeclContext(Actions.getCurScope(), CDC.getDC());
1670 }
1671 }
1672
1673 assert(!LPT.Toks.empty() && "Empty body!");
1674
1675 // Append the current token at the end of the new token stream so that it
1676 // doesn't get lost.
1677 LPT.Toks.push_back(Tok);
1678 PP.EnterTokenStream(LPT.Toks, true, /*IsReinject*/true);
1679
1680 // Consume the previously pushed token.
1681 ConsumeAnyToken(/*ConsumeCodeCompletionTok=*/true);
1682 assert(Tok.isOneOf(tok::l_brace, tok::colon, tok::kw_try) &&
1683 "Inline method not starting with '{', ':' or 'try'");
1684
1685 // Parse the method body. Function body parsing code is similar enough
1686 // to be re-used for method bodies as well.
1687 ParseScope FnScope(this, Scope::FnScope | Scope::DeclScope |
1688 Scope::CompoundStmtScope);
1689
1690 // Recreate the containing function DeclContext.
1691 Sema::ContextRAII FunctionSavedContext(Actions,
1692 Actions.getContainingDC(FunD));
1693
1694 Actions.ActOnStartOfFunctionDef(getCurScope(), FunD);
1695
1696 if (Tok.is(tok::kw_try)) {
1697 ParseFunctionTryBlock(LPT.D, FnScope);
1698 } else {
1699 if (Tok.is(tok::colon))
1700 ParseConstructorInitializer(LPT.D);
1701 else
1702 Actions.ActOnDefaultCtorInitializers(LPT.D);
1703
1704 if (Tok.is(tok::l_brace)) {
1705 assert((!isa<FunctionTemplateDecl>(LPT.D) ||
1706 cast<FunctionTemplateDecl>(LPT.D)
1707 ->getTemplateParameters()
1708 ->getDepth() == TemplateParameterDepth - 1) &&
1709 "TemplateParameterDepth should be greater than the depth of "
1710 "current template being instantiated!");
1711 ParseFunctionStatementBody(LPT.D, FnScope);
1712 Actions.UnmarkAsLateParsedTemplate(FunD);
1713 } else
1714 Actions.ActOnFinishFunctionBody(LPT.D, nullptr);
1715 }
1716
1717 // Exit scopes.
1718 FnScope.Exit();
1719 SmallVectorImpl<ParseScope *>::reverse_iterator I =
1720 TemplateParamScopeStack.rbegin();
1721 for (; I != TemplateParamScopeStack.rend(); ++I)
1722 delete *I;
1723 }
1724
1725 /// Lex a delayed template function for late parsing.
LexTemplateFunctionForLateParsing(CachedTokens & Toks)1726 void Parser::LexTemplateFunctionForLateParsing(CachedTokens &Toks) {
1727 tok::TokenKind kind = Tok.getKind();
1728 if (!ConsumeAndStoreFunctionPrologue(Toks)) {
1729 // Consume everything up to (and including) the matching right brace.
1730 ConsumeAndStoreUntil(tok::r_brace, Toks, /*StopAtSemi=*/false);
1731 }
1732
1733 // If we're in a function-try-block, we need to store all the catch blocks.
1734 if (kind == tok::kw_try) {
1735 while (Tok.is(tok::kw_catch)) {
1736 ConsumeAndStoreUntil(tok::l_brace, Toks, /*StopAtSemi=*/false);
1737 ConsumeAndStoreUntil(tok::r_brace, Toks, /*StopAtSemi=*/false);
1738 }
1739 }
1740 }
1741
1742 /// We've parsed something that could plausibly be intended to be a template
1743 /// name (\p LHS) followed by a '<' token, and the following code can't possibly
1744 /// be an expression. Determine if this is likely to be a template-id and if so,
1745 /// diagnose it.
diagnoseUnknownTemplateId(ExprResult LHS,SourceLocation Less)1746 bool Parser::diagnoseUnknownTemplateId(ExprResult LHS, SourceLocation Less) {
1747 TentativeParsingAction TPA(*this);
1748 // FIXME: We could look at the token sequence in a lot more detail here.
1749 if (SkipUntil(tok::greater, tok::greatergreater, tok::greatergreatergreater,
1750 StopAtSemi | StopBeforeMatch)) {
1751 TPA.Commit();
1752
1753 SourceLocation Greater;
1754 ParseGreaterThanInTemplateList(Greater, true, false);
1755 Actions.diagnoseExprIntendedAsTemplateName(getCurScope(), LHS,
1756 Less, Greater);
1757 return true;
1758 }
1759
1760 // There's no matching '>' token, this probably isn't supposed to be
1761 // interpreted as a template-id. Parse it as an (ill-formed) comparison.
1762 TPA.Revert();
1763 return false;
1764 }
1765
checkPotentialAngleBracket(ExprResult & PotentialTemplateName)1766 void Parser::checkPotentialAngleBracket(ExprResult &PotentialTemplateName) {
1767 assert(Tok.is(tok::less) && "not at a potential angle bracket");
1768
1769 bool DependentTemplateName = false;
1770 if (!Actions.mightBeIntendedToBeTemplateName(PotentialTemplateName,
1771 DependentTemplateName))
1772 return;
1773
1774 // OK, this might be a name that the user intended to be parsed as a
1775 // template-name, followed by a '<' token. Check for some easy cases.
1776
1777 // If we have potential_template<>, then it's supposed to be a template-name.
1778 if (NextToken().is(tok::greater) ||
1779 (getLangOpts().CPlusPlus11 &&
1780 NextToken().isOneOf(tok::greatergreater, tok::greatergreatergreater))) {
1781 SourceLocation Less = ConsumeToken();
1782 SourceLocation Greater;
1783 ParseGreaterThanInTemplateList(Greater, true, false);
1784 Actions.diagnoseExprIntendedAsTemplateName(
1785 getCurScope(), PotentialTemplateName, Less, Greater);
1786 // FIXME: Perform error recovery.
1787 PotentialTemplateName = ExprError();
1788 return;
1789 }
1790
1791 // If we have 'potential_template<type-id', assume it's supposed to be a
1792 // template-name if there's a matching '>' later on.
1793 {
1794 // FIXME: Avoid the tentative parse when NextToken() can't begin a type.
1795 TentativeParsingAction TPA(*this);
1796 SourceLocation Less = ConsumeToken();
1797 if (isTypeIdUnambiguously() &&
1798 diagnoseUnknownTemplateId(PotentialTemplateName, Less)) {
1799 TPA.Commit();
1800 // FIXME: Perform error recovery.
1801 PotentialTemplateName = ExprError();
1802 return;
1803 }
1804 TPA.Revert();
1805 }
1806
1807 // Otherwise, remember that we saw this in case we see a potentially-matching
1808 // '>' token later on.
1809 AngleBracketTracker::Priority Priority =
1810 (DependentTemplateName ? AngleBracketTracker::DependentName
1811 : AngleBracketTracker::PotentialTypo) |
1812 (Tok.hasLeadingSpace() ? AngleBracketTracker::SpaceBeforeLess
1813 : AngleBracketTracker::NoSpaceBeforeLess);
1814 AngleBrackets.add(*this, PotentialTemplateName.get(), Tok.getLocation(),
1815 Priority);
1816 }
1817
checkPotentialAngleBracketDelimiter(const AngleBracketTracker::Loc & LAngle,const Token & OpToken)1818 bool Parser::checkPotentialAngleBracketDelimiter(
1819 const AngleBracketTracker::Loc &LAngle, const Token &OpToken) {
1820 // If a comma in an expression context is followed by a type that can be a
1821 // template argument and cannot be an expression, then this is ill-formed,
1822 // but might be intended to be part of a template-id.
1823 if (OpToken.is(tok::comma) && isTypeIdUnambiguously() &&
1824 diagnoseUnknownTemplateId(LAngle.TemplateName, LAngle.LessLoc)) {
1825 AngleBrackets.clear(*this);
1826 return true;
1827 }
1828
1829 // If a context that looks like a template-id is followed by '()', then
1830 // this is ill-formed, but might be intended to be a template-id
1831 // followed by '()'.
1832 if (OpToken.is(tok::greater) && Tok.is(tok::l_paren) &&
1833 NextToken().is(tok::r_paren)) {
1834 Actions.diagnoseExprIntendedAsTemplateName(
1835 getCurScope(), LAngle.TemplateName, LAngle.LessLoc,
1836 OpToken.getLocation());
1837 AngleBrackets.clear(*this);
1838 return true;
1839 }
1840
1841 // After a '>' (etc), we're no longer potentially in a construct that's
1842 // intended to be treated as a template-id.
1843 if (OpToken.is(tok::greater) ||
1844 (getLangOpts().CPlusPlus11 &&
1845 OpToken.isOneOf(tok::greatergreater, tok::greatergreatergreater)))
1846 AngleBrackets.clear(*this);
1847 return false;
1848 }
1849