1 //===------- SemaTemplate.cpp - Semantic Analysis for C++ Templates -------===//
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 //===----------------------------------------------------------------------===//
8 // This file implements semantic analysis for C++ templates.
9 //===----------------------------------------------------------------------===//
11 #include "TreeTransform.h"
12 #include "clang/AST/ASTConsumer.h"
13 #include "clang/AST/ASTContext.h"
14 #include "clang/AST/DeclFriend.h"
15 #include "clang/AST/DeclTemplate.h"
16 #include "clang/AST/Expr.h"
17 #include "clang/AST/ExprCXX.h"
18 #include "clang/AST/RecursiveASTVisitor.h"
19 #include "clang/AST/TypeVisitor.h"
20 #include "clang/Basic/Builtins.h"
21 #include "clang/Basic/LangOptions.h"
22 #include "clang/Basic/PartialDiagnostic.h"
23 #include "clang/Basic/TargetInfo.h"
24 #include "clang/Sema/DeclSpec.h"
25 #include "clang/Sema/Lookup.h"
26 #include "clang/Sema/ParsedTemplate.h"
27 #include "clang/Sema/Scope.h"
28 #include "clang/Sema/SemaInternal.h"
29 #include "clang/Sema/Template.h"
30 #include "clang/Sema/TemplateDeduction.h"
31 #include "llvm/ADT/SmallBitVector.h"
32 #include "llvm/ADT/SmallString.h"
33 #include "llvm/ADT/StringExtras.h"
36 using namespace clang;
39 // Exported for use by Parser.
41 clang::getTemplateParamsRange(TemplateParameterList const * const *Ps,
43 if (!N) return SourceRange();
44 return SourceRange(Ps[0]->getTemplateLoc(), Ps[N-1]->getRAngleLoc());
48 /// [temp.constr.decl]p2: A template's associated constraints are
49 /// defined as a single constraint-expression derived from the introduced
50 /// constraint-expressions [ ... ].
52 /// \param Params The template parameter list and optional requires-clause.
54 /// \param FD The underlying templated function declaration for a function
56 static Expr *formAssociatedConstraints(TemplateParameterList *Params,
60 static Expr *clang::formAssociatedConstraints(TemplateParameterList *Params,
62 // FIXME: Concepts: collect additional introduced constraint-expressions
63 assert(!FD && "Cannot collect constraints from function declaration yet.");
64 return Params->getRequiresClause();
67 /// Determine whether the declaration found is acceptable as the name
68 /// of a template and, if so, return that template declaration. Otherwise,
71 /// Note that this may return an UnresolvedUsingValueDecl if AllowDependent
72 /// is true. In all other cases it will return a TemplateDecl (or null).
73 NamedDecl *Sema::getAsTemplateNameDecl(NamedDecl *D,
74 bool AllowFunctionTemplates,
75 bool AllowDependent) {
76 D = D->getUnderlyingDecl();
78 if (isa<TemplateDecl>(D)) {
79 if (!AllowFunctionTemplates && isa<FunctionTemplateDecl>(D))
85 if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(D)) {
86 // C++ [temp.local]p1:
87 // Like normal (non-template) classes, class templates have an
88 // injected-class-name (Clause 9). The injected-class-name
89 // can be used with or without a template-argument-list. When
90 // it is used without a template-argument-list, it is
91 // equivalent to the injected-class-name followed by the
92 // template-parameters of the class template enclosed in
93 // <>. When it is used with a template-argument-list, it
94 // refers to the specified class template specialization,
95 // which could be the current specialization or another
97 if (Record->isInjectedClassName()) {
98 Record = cast<CXXRecordDecl>(Record->getDeclContext());
99 if (Record->getDescribedClassTemplate())
100 return Record->getDescribedClassTemplate();
102 if (ClassTemplateSpecializationDecl *Spec
103 = dyn_cast<ClassTemplateSpecializationDecl>(Record))
104 return Spec->getSpecializedTemplate();
110 // 'using Dependent::foo;' can resolve to a template name.
111 // 'using typename Dependent::foo;' cannot (not even if 'foo' is an
112 // injected-class-name).
113 if (AllowDependent && isa<UnresolvedUsingValueDecl>(D))
119 void Sema::FilterAcceptableTemplateNames(LookupResult &R,
120 bool AllowFunctionTemplates,
121 bool AllowDependent) {
122 LookupResult::Filter filter = R.makeFilter();
123 while (filter.hasNext()) {
124 NamedDecl *Orig = filter.next();
125 if (!getAsTemplateNameDecl(Orig, AllowFunctionTemplates, AllowDependent))
131 bool Sema::hasAnyAcceptableTemplateNames(LookupResult &R,
132 bool AllowFunctionTemplates,
134 bool AllowNonTemplateFunctions) {
135 for (LookupResult::iterator I = R.begin(), IEnd = R.end(); I != IEnd; ++I) {
136 if (getAsTemplateNameDecl(*I, AllowFunctionTemplates, AllowDependent))
138 if (AllowNonTemplateFunctions &&
139 isa<FunctionDecl>((*I)->getUnderlyingDecl()))
146 TemplateNameKind Sema::isTemplateName(Scope *S,
148 bool hasTemplateKeyword,
149 const UnqualifiedId &Name,
150 ParsedType ObjectTypePtr,
151 bool EnteringContext,
152 TemplateTy &TemplateResult,
153 bool &MemberOfUnknownSpecialization) {
154 assert(getLangOpts().CPlusPlus && "No template names in C!");
156 DeclarationName TName;
157 MemberOfUnknownSpecialization = false;
159 switch (Name.getKind()) {
160 case UnqualifiedIdKind::IK_Identifier:
161 TName = DeclarationName(Name.Identifier);
164 case UnqualifiedIdKind::IK_OperatorFunctionId:
165 TName = Context.DeclarationNames.getCXXOperatorName(
166 Name.OperatorFunctionId.Operator);
169 case UnqualifiedIdKind::IK_LiteralOperatorId:
170 TName = Context.DeclarationNames.getCXXLiteralOperatorName(Name.Identifier);
174 return TNK_Non_template;
177 QualType ObjectType = ObjectTypePtr.get();
179 AssumedTemplateKind AssumedTemplate;
180 LookupResult R(*this, TName, Name.getBeginLoc(), LookupOrdinaryName);
181 if (LookupTemplateName(R, S, SS, ObjectType, EnteringContext,
182 MemberOfUnknownSpecialization, SourceLocation(),
184 return TNK_Non_template;
186 if (AssumedTemplate != AssumedTemplateKind::None) {
187 TemplateResult = TemplateTy::make(Context.getAssumedTemplateName(TName));
188 // Let the parser know whether we found nothing or found functions; if we
189 // found nothing, we want to more carefully check whether this is actually
190 // a function template name versus some other kind of undeclared identifier.
191 return AssumedTemplate == AssumedTemplateKind::FoundNothing
192 ? TNK_Undeclared_template
193 : TNK_Function_template;
197 return TNK_Non_template;
199 NamedDecl *D = nullptr;
200 if (R.isAmbiguous()) {
201 // If we got an ambiguity involving a non-function template, treat this
202 // as a template name, and pick an arbitrary template for error recovery.
203 bool AnyFunctionTemplates = false;
204 for (NamedDecl *FoundD : R) {
205 if (NamedDecl *FoundTemplate = getAsTemplateNameDecl(FoundD)) {
206 if (isa<FunctionTemplateDecl>(FoundTemplate))
207 AnyFunctionTemplates = true;
215 // If we didn't find any templates at all, this isn't a template name.
216 // Leave the ambiguity for a later lookup to diagnose.
217 if (!D && !AnyFunctionTemplates) {
218 R.suppressDiagnostics();
219 return TNK_Non_template;
222 // If the only templates were function templates, filter out the rest.
223 // We'll diagnose the ambiguity later.
225 FilterAcceptableTemplateNames(R);
228 // At this point, we have either picked a single template name declaration D
229 // or we have a non-empty set of results R containing either one template name
230 // declaration or a set of function templates.
232 TemplateName Template;
233 TemplateNameKind TemplateKind;
235 unsigned ResultCount = R.end() - R.begin();
236 if (!D && ResultCount > 1) {
237 // We assume that we'll preserve the qualifier from a function
238 // template name in other ways.
239 Template = Context.getOverloadedTemplateName(R.begin(), R.end());
240 TemplateKind = TNK_Function_template;
242 // We'll do this lookup again later.
243 R.suppressDiagnostics();
246 D = getAsTemplateNameDecl(*R.begin());
247 assert(D && "unambiguous result is not a template name");
250 if (isa<UnresolvedUsingValueDecl>(D)) {
251 // We don't yet know whether this is a template-name or not.
252 MemberOfUnknownSpecialization = true;
253 return TNK_Non_template;
256 TemplateDecl *TD = cast<TemplateDecl>(D);
258 if (SS.isSet() && !SS.isInvalid()) {
259 NestedNameSpecifier *Qualifier = SS.getScopeRep();
260 Template = Context.getQualifiedTemplateName(Qualifier,
261 hasTemplateKeyword, TD);
263 Template = TemplateName(TD);
266 if (isa<FunctionTemplateDecl>(TD)) {
267 TemplateKind = TNK_Function_template;
269 // We'll do this lookup again later.
270 R.suppressDiagnostics();
272 assert(isa<ClassTemplateDecl>(TD) || isa<TemplateTemplateParmDecl>(TD) ||
273 isa<TypeAliasTemplateDecl>(TD) || isa<VarTemplateDecl>(TD) ||
274 isa<BuiltinTemplateDecl>(TD) || isa<ConceptDecl>(TD));
276 isa<VarTemplateDecl>(TD) ? TNK_Var_template :
277 isa<ConceptDecl>(TD) ? TNK_Concept_template :
282 TemplateResult = TemplateTy::make(Template);
286 bool Sema::isDeductionGuideName(Scope *S, const IdentifierInfo &Name,
287 SourceLocation NameLoc,
288 ParsedTemplateTy *Template) {
290 bool MemberOfUnknownSpecialization = false;
292 // We could use redeclaration lookup here, but we don't need to: the
293 // syntactic form of a deduction guide is enough to identify it even
294 // if we can't look up the template name at all.
295 LookupResult R(*this, DeclarationName(&Name), NameLoc, LookupOrdinaryName);
296 if (LookupTemplateName(R, S, SS, /*ObjectType*/ QualType(),
297 /*EnteringContext*/ false,
298 MemberOfUnknownSpecialization))
301 if (R.empty()) return false;
302 if (R.isAmbiguous()) {
303 // FIXME: Diagnose an ambiguity if we find at least one template.
304 R.suppressDiagnostics();
308 // We only treat template-names that name type templates as valid deduction
310 TemplateDecl *TD = R.getAsSingle<TemplateDecl>();
311 if (!TD || !getAsTypeTemplateDecl(TD))
315 *Template = TemplateTy::make(TemplateName(TD));
319 bool Sema::DiagnoseUnknownTemplateName(const IdentifierInfo &II,
320 SourceLocation IILoc,
322 const CXXScopeSpec *SS,
323 TemplateTy &SuggestedTemplate,
324 TemplateNameKind &SuggestedKind) {
325 // We can't recover unless there's a dependent scope specifier preceding the
327 // FIXME: Typo correction?
328 if (!SS || !SS->isSet() || !isDependentScopeSpecifier(*SS) ||
329 computeDeclContext(*SS))
332 // The code is missing a 'template' keyword prior to the dependent template
334 NestedNameSpecifier *Qualifier = (NestedNameSpecifier*)SS->getScopeRep();
335 Diag(IILoc, diag::err_template_kw_missing)
336 << Qualifier << II.getName()
337 << FixItHint::CreateInsertion(IILoc, "template ");
339 = TemplateTy::make(Context.getDependentTemplateName(Qualifier, &II));
340 SuggestedKind = TNK_Dependent_template_name;
344 bool Sema::LookupTemplateName(LookupResult &Found,
345 Scope *S, CXXScopeSpec &SS,
347 bool EnteringContext,
348 bool &MemberOfUnknownSpecialization,
349 SourceLocation TemplateKWLoc,
350 AssumedTemplateKind *ATK) {
352 *ATK = AssumedTemplateKind::None;
354 Found.setTemplateNameLookup(true);
356 // Determine where to perform name lookup
357 MemberOfUnknownSpecialization = false;
358 DeclContext *LookupCtx = nullptr;
359 bool IsDependent = false;
360 if (!ObjectType.isNull()) {
361 // This nested-name-specifier occurs in a member access expression, e.g.,
362 // x->B::f, and we are looking into the type of the object.
363 assert(!SS.isSet() && "ObjectType and scope specifier cannot coexist");
364 LookupCtx = computeDeclContext(ObjectType);
365 IsDependent = !LookupCtx && ObjectType->isDependentType();
366 assert((IsDependent || !ObjectType->isIncompleteType() ||
367 ObjectType->castAs<TagType>()->isBeingDefined()) &&
368 "Caller should have completed object type");
370 // Template names cannot appear inside an Objective-C class or object type
373 // FIXME: This is wrong. For example:
375 // template<typename T> using Vec = T __attribute__((ext_vector_type(4)));
377 // vi.Vec<int>::~Vec<int>();
379 // ... should be accepted but we will not treat 'Vec' as a template name
380 // here. The right thing to do would be to check if the name is a valid
381 // vector component name, and look up a template name if not. And similarly
382 // for lookups into Objective-C class and object types, where the same
383 // problem can arise.
384 if (ObjectType->isObjCObjectOrInterfaceType() ||
385 ObjectType->isVectorType()) {
389 } else if (SS.isSet()) {
390 // This nested-name-specifier occurs after another nested-name-specifier,
391 // so long into the context associated with the prior nested-name-specifier.
392 LookupCtx = computeDeclContext(SS, EnteringContext);
393 IsDependent = !LookupCtx;
395 // The declaration context must be complete.
396 if (LookupCtx && RequireCompleteDeclContext(SS, LookupCtx))
400 bool ObjectTypeSearchedInScope = false;
401 bool AllowFunctionTemplatesInLookup = true;
403 // Perform "qualified" name lookup into the declaration context we
404 // computed, which is either the type of the base of a member access
405 // expression or the declaration context associated with a prior
406 // nested-name-specifier.
407 LookupQualifiedName(Found, LookupCtx);
409 // FIXME: The C++ standard does not clearly specify what happens in the
410 // case where the object type is dependent, and implementations vary. In
411 // Clang, we treat a name after a . or -> as a template-name if lookup
412 // finds a non-dependent member or member of the current instantiation that
413 // is a type template, or finds no such members and lookup in the context
414 // of the postfix-expression finds a type template. In the latter case, the
415 // name is nonetheless dependent, and we may resolve it to a member of an
416 // unknown specialization when we come to instantiate the template.
417 IsDependent |= Found.wasNotFoundInCurrentInstantiation();
420 if (!SS.isSet() && (ObjectType.isNull() || Found.empty())) {
421 // C++ [basic.lookup.classref]p1:
422 // In a class member access expression (5.2.5), if the . or -> token is
423 // immediately followed by an identifier followed by a <, the
424 // identifier must be looked up to determine whether the < is the
425 // beginning of a template argument list (14.2) or a less-than operator.
426 // The identifier is first looked up in the class of the object
427 // expression. If the identifier is not found, it is then looked up in
428 // the context of the entire postfix-expression and shall name a class
431 LookupName(Found, S);
433 if (!ObjectType.isNull()) {
434 // FIXME: We should filter out all non-type templates here, particularly
435 // variable templates and concepts. But the exclusion of alias templates
436 // and template template parameters is a wording defect.
437 AllowFunctionTemplatesInLookup = false;
438 ObjectTypeSearchedInScope = true;
441 IsDependent |= Found.wasNotFoundInCurrentInstantiation();
444 if (Found.isAmbiguous())
447 if (ATK && !SS.isSet() && ObjectType.isNull() && TemplateKWLoc.isInvalid()) {
448 // C++2a [temp.names]p2:
449 // A name is also considered to refer to a template if it is an
450 // unqualified-id followed by a < and name lookup finds either one or more
451 // functions or finds nothing.
453 // To keep our behavior consistent, we apply the "finds nothing" part in
454 // all language modes, and diagnose the empty lookup in ActOnCallExpr if we
455 // successfully form a call to an undeclared template-id.
457 getLangOpts().CPlusPlus2a &&
458 std::all_of(Found.begin(), Found.end(), [](NamedDecl *ND) {
459 return isa<FunctionDecl>(ND->getUnderlyingDecl());
461 if (AllFunctions || (Found.empty() && !IsDependent)) {
462 // If lookup found any functions, or if this is a name that can only be
463 // used for a function, then strongly assume this is a function
465 *ATK = (Found.empty() && Found.getLookupName().isIdentifier())
466 ? AssumedTemplateKind::FoundNothing
467 : AssumedTemplateKind::FoundFunctions;
473 if (Found.empty() && !IsDependent) {
474 // If we did not find any names, attempt to correct any typos.
475 DeclarationName Name = Found.getLookupName();
477 // Simple filter callback that, for keywords, only accepts the C++ *_cast
478 DefaultFilterCCC FilterCCC{};
479 FilterCCC.WantTypeSpecifiers = false;
480 FilterCCC.WantExpressionKeywords = false;
481 FilterCCC.WantRemainingKeywords = false;
482 FilterCCC.WantCXXNamedCasts = true;
483 if (TypoCorrection Corrected =
484 CorrectTypo(Found.getLookupNameInfo(), Found.getLookupKind(), S,
485 &SS, FilterCCC, CTK_ErrorRecovery, LookupCtx)) {
486 if (auto *ND = Corrected.getFoundDecl())
488 FilterAcceptableTemplateNames(Found);
489 if (Found.isAmbiguous()) {
491 } else if (!Found.empty()) {
492 Found.setLookupName(Corrected.getCorrection());
494 std::string CorrectedStr(Corrected.getAsString(getLangOpts()));
495 bool DroppedSpecifier = Corrected.WillReplaceSpecifier() &&
496 Name.getAsString() == CorrectedStr;
497 diagnoseTypo(Corrected, PDiag(diag::err_no_member_template_suggest)
498 << Name << LookupCtx << DroppedSpecifier
501 diagnoseTypo(Corrected, PDiag(diag::err_no_template_suggest) << Name);
507 NamedDecl *ExampleLookupResult =
508 Found.empty() ? nullptr : Found.getRepresentativeDecl();
509 FilterAcceptableTemplateNames(Found, AllowFunctionTemplatesInLookup);
512 MemberOfUnknownSpecialization = true;
516 // If a 'template' keyword was used, a lookup that finds only non-template
517 // names is an error.
518 if (ExampleLookupResult && TemplateKWLoc.isValid()) {
519 Diag(Found.getNameLoc(), diag::err_template_kw_refers_to_non_template)
520 << Found.getLookupName() << SS.getRange();
521 Diag(ExampleLookupResult->getUnderlyingDecl()->getLocation(),
522 diag::note_template_kw_refers_to_non_template)
523 << Found.getLookupName();
530 if (S && !ObjectType.isNull() && !ObjectTypeSearchedInScope &&
531 !getLangOpts().CPlusPlus11) {
532 // C++03 [basic.lookup.classref]p1:
533 // [...] If the lookup in the class of the object expression finds a
534 // template, the name is also looked up in the context of the entire
535 // postfix-expression and [...]
537 // Note: C++11 does not perform this second lookup.
538 LookupResult FoundOuter(*this, Found.getLookupName(), Found.getNameLoc(),
540 FoundOuter.setTemplateNameLookup(true);
541 LookupName(FoundOuter, S);
542 // FIXME: We silently accept an ambiguous lookup here, in violation of
544 FilterAcceptableTemplateNames(FoundOuter, /*AllowFunctionTemplates=*/false);
546 NamedDecl *OuterTemplate;
547 if (FoundOuter.empty()) {
548 // - if the name is not found, the name found in the class of the
549 // object expression is used, otherwise
550 } else if (FoundOuter.isAmbiguous() || !FoundOuter.isSingleResult() ||
552 getAsTemplateNameDecl(FoundOuter.getFoundDecl()))) {
553 // - if the name is found in the context of the entire
554 // postfix-expression and does not name a class template, the name
555 // found in the class of the object expression is used, otherwise
557 } else if (!Found.isSuppressingDiagnostics()) {
558 // - if the name found is a class template, it must refer to the same
559 // entity as the one found in the class of the object expression,
560 // otherwise the program is ill-formed.
561 if (!Found.isSingleResult() ||
562 getAsTemplateNameDecl(Found.getFoundDecl())->getCanonicalDecl() !=
563 OuterTemplate->getCanonicalDecl()) {
564 Diag(Found.getNameLoc(),
565 diag::ext_nested_name_member_ref_lookup_ambiguous)
566 << Found.getLookupName()
568 Diag(Found.getRepresentativeDecl()->getLocation(),
569 diag::note_ambig_member_ref_object_type)
571 Diag(FoundOuter.getFoundDecl()->getLocation(),
572 diag::note_ambig_member_ref_scope);
574 // Recover by taking the template that we found in the object
575 // expression's type.
583 void Sema::diagnoseExprIntendedAsTemplateName(Scope *S, ExprResult TemplateName,
585 SourceLocation Greater) {
586 if (TemplateName.isInvalid())
589 DeclarationNameInfo NameInfo;
591 LookupNameKind LookupKind;
593 DeclContext *LookupCtx = nullptr;
594 NamedDecl *Found = nullptr;
595 bool MissingTemplateKeyword = false;
597 // Figure out what name we looked up.
598 if (auto *DRE = dyn_cast<DeclRefExpr>(TemplateName.get())) {
599 NameInfo = DRE->getNameInfo();
600 SS.Adopt(DRE->getQualifierLoc());
601 LookupKind = LookupOrdinaryName;
602 Found = DRE->getFoundDecl();
603 } else if (auto *ME = dyn_cast<MemberExpr>(TemplateName.get())) {
604 NameInfo = ME->getMemberNameInfo();
605 SS.Adopt(ME->getQualifierLoc());
606 LookupKind = LookupMemberName;
607 LookupCtx = ME->getBase()->getType()->getAsCXXRecordDecl();
608 Found = ME->getMemberDecl();
609 } else if (auto *DSDRE =
610 dyn_cast<DependentScopeDeclRefExpr>(TemplateName.get())) {
611 NameInfo = DSDRE->getNameInfo();
612 SS.Adopt(DSDRE->getQualifierLoc());
613 MissingTemplateKeyword = true;
614 } else if (auto *DSME =
615 dyn_cast<CXXDependentScopeMemberExpr>(TemplateName.get())) {
616 NameInfo = DSME->getMemberNameInfo();
617 SS.Adopt(DSME->getQualifierLoc());
618 MissingTemplateKeyword = true;
620 llvm_unreachable("unexpected kind of potential template name");
623 // If this is a dependent-scope lookup, diagnose that the 'template' keyword
625 if (MissingTemplateKeyword) {
626 Diag(NameInfo.getBeginLoc(), diag::err_template_kw_missing)
627 << "" << NameInfo.getName().getAsString() << SourceRange(Less, Greater);
631 // Try to correct the name by looking for templates and C++ named casts.
632 struct TemplateCandidateFilter : CorrectionCandidateCallback {
634 TemplateCandidateFilter(Sema &S) : S(S) {
635 WantTypeSpecifiers = false;
636 WantExpressionKeywords = false;
637 WantRemainingKeywords = false;
638 WantCXXNamedCasts = true;
640 bool ValidateCandidate(const TypoCorrection &Candidate) override {
641 if (auto *ND = Candidate.getCorrectionDecl())
642 return S.getAsTemplateNameDecl(ND);
643 return Candidate.isKeyword();
646 std::unique_ptr<CorrectionCandidateCallback> clone() override {
647 return llvm::make_unique<TemplateCandidateFilter>(*this);
651 DeclarationName Name = NameInfo.getName();
652 TemplateCandidateFilter CCC(*this);
653 if (TypoCorrection Corrected = CorrectTypo(NameInfo, LookupKind, S, &SS, CCC,
654 CTK_ErrorRecovery, LookupCtx)) {
655 auto *ND = Corrected.getFoundDecl();
657 ND = getAsTemplateNameDecl(ND);
658 if (ND || Corrected.isKeyword()) {
660 std::string CorrectedStr(Corrected.getAsString(getLangOpts()));
661 bool DroppedSpecifier = Corrected.WillReplaceSpecifier() &&
662 Name.getAsString() == CorrectedStr;
663 diagnoseTypo(Corrected,
664 PDiag(diag::err_non_template_in_member_template_id_suggest)
665 << Name << LookupCtx << DroppedSpecifier
666 << SS.getRange(), false);
668 diagnoseTypo(Corrected,
669 PDiag(diag::err_non_template_in_template_id_suggest)
673 Diag(Found->getLocation(),
674 diag::note_non_template_in_template_id_found);
679 Diag(NameInfo.getLoc(), diag::err_non_template_in_template_id)
680 << Name << SourceRange(Less, Greater);
682 Diag(Found->getLocation(), diag::note_non_template_in_template_id_found);
685 /// ActOnDependentIdExpression - Handle a dependent id-expression that
686 /// was just parsed. This is only possible with an explicit scope
687 /// specifier naming a dependent type.
689 Sema::ActOnDependentIdExpression(const CXXScopeSpec &SS,
690 SourceLocation TemplateKWLoc,
691 const DeclarationNameInfo &NameInfo,
692 bool isAddressOfOperand,
693 const TemplateArgumentListInfo *TemplateArgs) {
694 DeclContext *DC = getFunctionLevelDeclContext();
696 // C++11 [expr.prim.general]p12:
697 // An id-expression that denotes a non-static data member or non-static
698 // member function of a class can only be used:
700 // - if that id-expression denotes a non-static data member and it
701 // appears in an unevaluated operand.
703 // If this might be the case, form a DependentScopeDeclRefExpr instead of a
704 // CXXDependentScopeMemberExpr. The former can instantiate to either
705 // DeclRefExpr or MemberExpr depending on lookup results, while the latter is
706 // always a MemberExpr.
707 bool MightBeCxx11UnevalField =
708 getLangOpts().CPlusPlus11 && isUnevaluatedContext();
710 // Check if the nested name specifier is an enum type.
712 if (NestedNameSpecifier *NNS = SS.getScopeRep())
713 IsEnum = dyn_cast_or_null<EnumType>(NNS->getAsType());
715 if (!MightBeCxx11UnevalField && !isAddressOfOperand && !IsEnum &&
716 isa<CXXMethodDecl>(DC) && cast<CXXMethodDecl>(DC)->isInstance()) {
717 QualType ThisType = cast<CXXMethodDecl>(DC)->getThisType();
719 // Since the 'this' expression is synthesized, we don't need to
720 // perform the double-lookup check.
721 NamedDecl *FirstQualifierInScope = nullptr;
723 return CXXDependentScopeMemberExpr::Create(
724 Context, /*This*/ nullptr, ThisType, /*IsArrow*/ true,
725 /*Op*/ SourceLocation(), SS.getWithLocInContext(Context), TemplateKWLoc,
726 FirstQualifierInScope, NameInfo, TemplateArgs);
729 return BuildDependentDeclRefExpr(SS, TemplateKWLoc, NameInfo, TemplateArgs);
733 Sema::BuildDependentDeclRefExpr(const CXXScopeSpec &SS,
734 SourceLocation TemplateKWLoc,
735 const DeclarationNameInfo &NameInfo,
736 const TemplateArgumentListInfo *TemplateArgs) {
737 return DependentScopeDeclRefExpr::Create(
738 Context, SS.getWithLocInContext(Context), TemplateKWLoc, NameInfo,
743 /// Determine whether we would be unable to instantiate this template (because
744 /// it either has no definition, or is in the process of being instantiated).
745 bool Sema::DiagnoseUninstantiableTemplate(SourceLocation PointOfInstantiation,
746 NamedDecl *Instantiation,
747 bool InstantiatedFromMember,
748 const NamedDecl *Pattern,
749 const NamedDecl *PatternDef,
750 TemplateSpecializationKind TSK,
751 bool Complain /*= true*/) {
752 assert(isa<TagDecl>(Instantiation) || isa<FunctionDecl>(Instantiation) ||
753 isa<VarDecl>(Instantiation));
755 bool IsEntityBeingDefined = false;
756 if (const TagDecl *TD = dyn_cast_or_null<TagDecl>(PatternDef))
757 IsEntityBeingDefined = TD->isBeingDefined();
759 if (PatternDef && !IsEntityBeingDefined) {
760 NamedDecl *SuggestedDef = nullptr;
761 if (!hasVisibleDefinition(const_cast<NamedDecl*>(PatternDef), &SuggestedDef,
762 /*OnlyNeedComplete*/false)) {
763 // If we're allowed to diagnose this and recover, do so.
764 bool Recover = Complain && !isSFINAEContext();
766 diagnoseMissingImport(PointOfInstantiation, SuggestedDef,
767 Sema::MissingImportKind::Definition, Recover);
773 if (!Complain || (PatternDef && PatternDef->isInvalidDecl()))
776 llvm::Optional<unsigned> Note;
777 QualType InstantiationTy;
778 if (TagDecl *TD = dyn_cast<TagDecl>(Instantiation))
779 InstantiationTy = Context.getTypeDeclType(TD);
781 Diag(PointOfInstantiation,
782 diag::err_template_instantiate_within_definition)
783 << /*implicit|explicit*/(TSK != TSK_ImplicitInstantiation)
785 // Not much point in noting the template declaration here, since
786 // we're lexically inside it.
787 Instantiation->setInvalidDecl();
788 } else if (InstantiatedFromMember) {
789 if (isa<FunctionDecl>(Instantiation)) {
790 Diag(PointOfInstantiation,
791 diag::err_explicit_instantiation_undefined_member)
792 << /*member function*/ 1 << Instantiation->getDeclName()
793 << Instantiation->getDeclContext();
794 Note = diag::note_explicit_instantiation_here;
796 assert(isa<TagDecl>(Instantiation) && "Must be a TagDecl!");
797 Diag(PointOfInstantiation,
798 diag::err_implicit_instantiate_member_undefined)
800 Note = diag::note_member_declared_at;
803 if (isa<FunctionDecl>(Instantiation)) {
804 Diag(PointOfInstantiation,
805 diag::err_explicit_instantiation_undefined_func_template)
807 Note = diag::note_explicit_instantiation_here;
808 } else if (isa<TagDecl>(Instantiation)) {
809 Diag(PointOfInstantiation, diag::err_template_instantiate_undefined)
810 << (TSK != TSK_ImplicitInstantiation)
812 Note = diag::note_template_decl_here;
814 assert(isa<VarDecl>(Instantiation) && "Must be a VarDecl!");
815 if (isa<VarTemplateSpecializationDecl>(Instantiation)) {
816 Diag(PointOfInstantiation,
817 diag::err_explicit_instantiation_undefined_var_template)
819 Instantiation->setInvalidDecl();
821 Diag(PointOfInstantiation,
822 diag::err_explicit_instantiation_undefined_member)
823 << /*static data member*/ 2 << Instantiation->getDeclName()
824 << Instantiation->getDeclContext();
825 Note = diag::note_explicit_instantiation_here;
828 if (Note) // Diagnostics were emitted.
829 Diag(Pattern->getLocation(), Note.getValue());
831 // In general, Instantiation isn't marked invalid to get more than one
832 // error for multiple undefined instantiations. But the code that does
833 // explicit declaration -> explicit definition conversion can't handle
834 // invalid declarations, so mark as invalid in that case.
835 if (TSK == TSK_ExplicitInstantiationDeclaration)
836 Instantiation->setInvalidDecl();
840 /// DiagnoseTemplateParameterShadow - Produce a diagnostic complaining
841 /// that the template parameter 'PrevDecl' is being shadowed by a new
842 /// declaration at location Loc. Returns true to indicate that this is
843 /// an error, and false otherwise.
844 void Sema::DiagnoseTemplateParameterShadow(SourceLocation Loc, Decl *PrevDecl) {
845 assert(PrevDecl->isTemplateParameter() && "Not a template parameter");
847 // Microsoft Visual C++ permits template parameters to be shadowed.
848 if (getLangOpts().MicrosoftExt)
851 // C++ [temp.local]p4:
852 // A template-parameter shall not be redeclared within its
853 // scope (including nested scopes).
854 Diag(Loc, diag::err_template_param_shadow)
855 << cast<NamedDecl>(PrevDecl)->getDeclName();
856 Diag(PrevDecl->getLocation(), diag::note_template_param_here);
859 /// AdjustDeclIfTemplate - If the given decl happens to be a template, reset
860 /// the parameter D to reference the templated declaration and return a pointer
861 /// to the template declaration. Otherwise, do nothing to D and return null.
862 TemplateDecl *Sema::AdjustDeclIfTemplate(Decl *&D) {
863 if (TemplateDecl *Temp = dyn_cast_or_null<TemplateDecl>(D)) {
864 D = Temp->getTemplatedDecl();
870 ParsedTemplateArgument ParsedTemplateArgument::getTemplatePackExpansion(
871 SourceLocation EllipsisLoc) const {
872 assert(Kind == Template &&
873 "Only template template arguments can be pack expansions here");
874 assert(getAsTemplate().get().containsUnexpandedParameterPack() &&
875 "Template template argument pack expansion without packs");
876 ParsedTemplateArgument Result(*this);
877 Result.EllipsisLoc = EllipsisLoc;
881 static TemplateArgumentLoc translateTemplateArgument(Sema &SemaRef,
882 const ParsedTemplateArgument &Arg) {
884 switch (Arg.getKind()) {
885 case ParsedTemplateArgument::Type: {
887 QualType T = SemaRef.GetTypeFromParser(Arg.getAsType(), &DI);
889 DI = SemaRef.Context.getTrivialTypeSourceInfo(T, Arg.getLocation());
890 return TemplateArgumentLoc(TemplateArgument(T), DI);
893 case ParsedTemplateArgument::NonType: {
894 Expr *E = static_cast<Expr *>(Arg.getAsExpr());
895 return TemplateArgumentLoc(TemplateArgument(E), E);
898 case ParsedTemplateArgument::Template: {
899 TemplateName Template = Arg.getAsTemplate().get();
900 TemplateArgument TArg;
901 if (Arg.getEllipsisLoc().isValid())
902 TArg = TemplateArgument(Template, Optional<unsigned int>());
905 return TemplateArgumentLoc(TArg,
906 Arg.getScopeSpec().getWithLocInContext(
909 Arg.getEllipsisLoc());
913 llvm_unreachable("Unhandled parsed template argument");
916 /// Translates template arguments as provided by the parser
917 /// into template arguments used by semantic analysis.
918 void Sema::translateTemplateArguments(const ASTTemplateArgsPtr &TemplateArgsIn,
919 TemplateArgumentListInfo &TemplateArgs) {
920 for (unsigned I = 0, Last = TemplateArgsIn.size(); I != Last; ++I)
921 TemplateArgs.addArgument(translateTemplateArgument(*this,
925 static void maybeDiagnoseTemplateParameterShadow(Sema &SemaRef, Scope *S,
927 IdentifierInfo *Name) {
928 NamedDecl *PrevDecl = SemaRef.LookupSingleName(
929 S, Name, Loc, Sema::LookupOrdinaryName, Sema::ForVisibleRedeclaration);
930 if (PrevDecl && PrevDecl->isTemplateParameter())
931 SemaRef.DiagnoseTemplateParameterShadow(Loc, PrevDecl);
934 /// Convert a parsed type into a parsed template argument. This is mostly
935 /// trivial, except that we may have parsed a C++17 deduced class template
936 /// specialization type, in which case we should form a template template
937 /// argument instead of a type template argument.
938 ParsedTemplateArgument Sema::ActOnTemplateTypeArgument(TypeResult ParsedType) {
939 TypeSourceInfo *TInfo;
940 QualType T = GetTypeFromParser(ParsedType.get(), &TInfo);
942 return ParsedTemplateArgument();
943 assert(TInfo && "template argument with no location");
945 // If we might have formed a deduced template specialization type, convert
946 // it to a template template argument.
947 if (getLangOpts().CPlusPlus17) {
948 TypeLoc TL = TInfo->getTypeLoc();
949 SourceLocation EllipsisLoc;
950 if (auto PET = TL.getAs<PackExpansionTypeLoc>()) {
951 EllipsisLoc = PET.getEllipsisLoc();
952 TL = PET.getPatternLoc();
956 if (auto ET = TL.getAs<ElaboratedTypeLoc>()) {
957 SS.Adopt(ET.getQualifierLoc());
958 TL = ET.getNamedTypeLoc();
961 if (auto DTST = TL.getAs<DeducedTemplateSpecializationTypeLoc>()) {
962 TemplateName Name = DTST.getTypePtr()->getTemplateName();
964 Name = Context.getQualifiedTemplateName(SS.getScopeRep(),
965 /*HasTemplateKeyword*/ false,
966 Name.getAsTemplateDecl());
967 ParsedTemplateArgument Result(SS, TemplateTy::make(Name),
968 DTST.getTemplateNameLoc());
969 if (EllipsisLoc.isValid())
970 Result = Result.getTemplatePackExpansion(EllipsisLoc);
975 // This is a normal type template argument. Note, if the type template
976 // argument is an injected-class-name for a template, it has a dual nature
977 // and can be used as either a type or a template. We handle that in
978 // convertTypeTemplateArgumentToTemplate.
979 return ParsedTemplateArgument(ParsedTemplateArgument::Type,
980 ParsedType.get().getAsOpaquePtr(),
981 TInfo->getTypeLoc().getBeginLoc());
984 /// ActOnTypeParameter - Called when a C++ template type parameter
985 /// (e.g., "typename T") has been parsed. Typename specifies whether
986 /// the keyword "typename" was used to declare the type parameter
987 /// (otherwise, "class" was used), and KeyLoc is the location of the
988 /// "class" or "typename" keyword. ParamName is the name of the
989 /// parameter (NULL indicates an unnamed template parameter) and
990 /// ParamNameLoc is the location of the parameter name (if any).
991 /// If the type parameter has a default argument, it will be added
992 /// later via ActOnTypeParameterDefault.
993 NamedDecl *Sema::ActOnTypeParameter(Scope *S, bool Typename,
994 SourceLocation EllipsisLoc,
995 SourceLocation KeyLoc,
996 IdentifierInfo *ParamName,
997 SourceLocation ParamNameLoc,
998 unsigned Depth, unsigned Position,
999 SourceLocation EqualLoc,
1000 ParsedType DefaultArg) {
1001 assert(S->isTemplateParamScope() &&
1002 "Template type parameter not in template parameter scope!");
1004 SourceLocation Loc = ParamNameLoc;
1008 bool IsParameterPack = EllipsisLoc.isValid();
1009 TemplateTypeParmDecl *Param
1010 = TemplateTypeParmDecl::Create(Context, Context.getTranslationUnitDecl(),
1011 KeyLoc, Loc, Depth, Position, ParamName,
1012 Typename, IsParameterPack);
1013 Param->setAccess(AS_public);
1016 maybeDiagnoseTemplateParameterShadow(*this, S, ParamNameLoc, ParamName);
1018 // Add the template parameter into the current scope.
1020 IdResolver.AddDecl(Param);
1023 // C++0x [temp.param]p9:
1024 // A default template-argument may be specified for any kind of
1025 // template-parameter that is not a template parameter pack.
1026 if (DefaultArg && IsParameterPack) {
1027 Diag(EqualLoc, diag::err_template_param_pack_default_arg);
1028 DefaultArg = nullptr;
1031 // Handle the default argument, if provided.
1033 TypeSourceInfo *DefaultTInfo;
1034 GetTypeFromParser(DefaultArg, &DefaultTInfo);
1036 assert(DefaultTInfo && "expected source information for type");
1038 // Check for unexpanded parameter packs.
1039 if (DiagnoseUnexpandedParameterPack(Loc, DefaultTInfo,
1040 UPPC_DefaultArgument))
1043 // Check the template argument itself.
1044 if (CheckTemplateArgument(Param, DefaultTInfo)) {
1045 Param->setInvalidDecl();
1049 Param->setDefaultArgument(DefaultTInfo);
1055 /// Check that the type of a non-type template parameter is
1058 /// \returns the (possibly-promoted) parameter type if valid;
1059 /// otherwise, produces a diagnostic and returns a NULL type.
1060 QualType Sema::CheckNonTypeTemplateParameterType(TypeSourceInfo *&TSI,
1061 SourceLocation Loc) {
1062 if (TSI->getType()->isUndeducedType()) {
1063 // C++17 [temp.dep.expr]p3:
1064 // An id-expression is type-dependent if it contains
1065 // - an identifier associated by name lookup with a non-type
1066 // template-parameter declared with a type that contains a
1067 // placeholder type (7.1.7.4),
1068 TSI = SubstAutoTypeSourceInfo(TSI, Context.DependentTy);
1071 return CheckNonTypeTemplateParameterType(TSI->getType(), Loc);
1074 QualType Sema::CheckNonTypeTemplateParameterType(QualType T,
1075 SourceLocation Loc) {
1076 // We don't allow variably-modified types as the type of non-type template
1078 if (T->isVariablyModifiedType()) {
1079 Diag(Loc, diag::err_variably_modified_nontype_template_param)
1084 // C++ [temp.param]p4:
1086 // A non-type template-parameter shall have one of the following
1087 // (optionally cv-qualified) types:
1089 // -- integral or enumeration type,
1090 if (T->isIntegralOrEnumerationType() ||
1091 // -- pointer to object or pointer to function,
1092 T->isPointerType() ||
1093 // -- reference to object or reference to function,
1094 T->isReferenceType() ||
1095 // -- pointer to member,
1096 T->isMemberPointerType() ||
1097 // -- std::nullptr_t.
1098 T->isNullPtrType() ||
1099 // If T is a dependent type, we can't do the check now, so we
1100 // assume that it is well-formed.
1101 T->isDependentType() ||
1102 // Allow use of auto in template parameter declarations.
1103 T->isUndeducedType()) {
1104 // C++ [temp.param]p5: The top-level cv-qualifiers on the template-parameter
1105 // are ignored when determining its type.
1106 return T.getUnqualifiedType();
1109 // C++ [temp.param]p8:
1111 // A non-type template-parameter of type "array of T" or
1112 // "function returning T" is adjusted to be of type "pointer to
1113 // T" or "pointer to function returning T", respectively.
1114 else if (T->isArrayType() || T->isFunctionType())
1115 return Context.getDecayedType(T);
1117 Diag(Loc, diag::err_template_nontype_parm_bad_type)
1123 NamedDecl *Sema::ActOnNonTypeTemplateParameter(Scope *S, Declarator &D,
1126 SourceLocation EqualLoc,
1128 TypeSourceInfo *TInfo = GetTypeForDeclarator(D, S);
1130 // Check that we have valid decl-specifiers specified.
1131 auto CheckValidDeclSpecifiers = [this, &D] {
1134 // template-parameter:
1136 // parameter-declaration
1138 // ... A storage class shall not be specified in a template-parameter
1141 // The typedef specifier [...] shall not be used in the decl-specifier-seq
1142 // of a parameter-declaration
1143 const DeclSpec &DS = D.getDeclSpec();
1144 auto EmitDiag = [this](SourceLocation Loc) {
1145 Diag(Loc, diag::err_invalid_decl_specifier_in_nontype_parm)
1146 << FixItHint::CreateRemoval(Loc);
1148 if (DS.getStorageClassSpec() != DeclSpec::SCS_unspecified)
1149 EmitDiag(DS.getStorageClassSpecLoc());
1151 if (DS.getThreadStorageClassSpec() != TSCS_unspecified)
1152 EmitDiag(DS.getThreadStorageClassSpecLoc());
1155 // The inline specifier can be applied only to the declaration or
1156 // definition of a variable or function.
1158 if (DS.isInlineSpecified())
1159 EmitDiag(DS.getInlineSpecLoc());
1161 // [dcl.constexpr]p1:
1162 // The constexpr specifier shall be applied only to the definition of a
1163 // variable or variable template or the declaration of a function or
1164 // function template.
1166 if (DS.hasConstexprSpecifier())
1167 EmitDiag(DS.getConstexprSpecLoc());
1169 // [dcl.fct.spec]p1:
1170 // Function-specifiers can be used only in function declarations.
1172 if (DS.isVirtualSpecified())
1173 EmitDiag(DS.getVirtualSpecLoc());
1175 if (DS.hasExplicitSpecifier())
1176 EmitDiag(DS.getExplicitSpecLoc());
1178 if (DS.isNoreturnSpecified())
1179 EmitDiag(DS.getNoreturnSpecLoc());
1182 CheckValidDeclSpecifiers();
1184 if (TInfo->getType()->isUndeducedType()) {
1185 Diag(D.getIdentifierLoc(),
1186 diag::warn_cxx14_compat_template_nontype_parm_auto_type)
1187 << QualType(TInfo->getType()->getContainedAutoType(), 0);
1190 assert(S->isTemplateParamScope() &&
1191 "Non-type template parameter not in template parameter scope!");
1192 bool Invalid = false;
1194 QualType T = CheckNonTypeTemplateParameterType(TInfo, D.getIdentifierLoc());
1196 T = Context.IntTy; // Recover with an 'int' type.
1200 CheckFunctionOrTemplateParamDeclarator(S, D);
1202 IdentifierInfo *ParamName = D.getIdentifier();
1203 bool IsParameterPack = D.hasEllipsis();
1204 NonTypeTemplateParmDecl *Param = NonTypeTemplateParmDecl::Create(
1205 Context, Context.getTranslationUnitDecl(), D.getBeginLoc(),
1206 D.getIdentifierLoc(), Depth, Position, ParamName, T, IsParameterPack,
1208 Param->setAccess(AS_public);
1211 Param->setInvalidDecl();
1214 maybeDiagnoseTemplateParameterShadow(*this, S, D.getIdentifierLoc(),
1217 // Add the template parameter into the current scope.
1219 IdResolver.AddDecl(Param);
1222 // C++0x [temp.param]p9:
1223 // A default template-argument may be specified for any kind of
1224 // template-parameter that is not a template parameter pack.
1225 if (Default && IsParameterPack) {
1226 Diag(EqualLoc, diag::err_template_param_pack_default_arg);
1230 // Check the well-formedness of the default template argument, if provided.
1232 // Check for unexpanded parameter packs.
1233 if (DiagnoseUnexpandedParameterPack(Default, UPPC_DefaultArgument))
1236 TemplateArgument Converted;
1237 ExprResult DefaultRes =
1238 CheckTemplateArgument(Param, Param->getType(), Default, Converted);
1239 if (DefaultRes.isInvalid()) {
1240 Param->setInvalidDecl();
1243 Default = DefaultRes.get();
1245 Param->setDefaultArgument(Default);
1251 /// ActOnTemplateTemplateParameter - Called when a C++ template template
1252 /// parameter (e.g. T in template <template \<typename> class T> class array)
1253 /// has been parsed. S is the current scope.
1254 NamedDecl *Sema::ActOnTemplateTemplateParameter(Scope* S,
1255 SourceLocation TmpLoc,
1256 TemplateParameterList *Params,
1257 SourceLocation EllipsisLoc,
1258 IdentifierInfo *Name,
1259 SourceLocation NameLoc,
1262 SourceLocation EqualLoc,
1263 ParsedTemplateArgument Default) {
1264 assert(S->isTemplateParamScope() &&
1265 "Template template parameter not in template parameter scope!");
1267 // Construct the parameter object.
1268 bool IsParameterPack = EllipsisLoc.isValid();
1269 TemplateTemplateParmDecl *Param =
1270 TemplateTemplateParmDecl::Create(Context, Context.getTranslationUnitDecl(),
1271 NameLoc.isInvalid()? TmpLoc : NameLoc,
1272 Depth, Position, IsParameterPack,
1274 Param->setAccess(AS_public);
1276 // If the template template parameter has a name, then link the identifier
1277 // into the scope and lookup mechanisms.
1279 maybeDiagnoseTemplateParameterShadow(*this, S, NameLoc, Name);
1282 IdResolver.AddDecl(Param);
1285 if (Params->size() == 0) {
1286 Diag(Param->getLocation(), diag::err_template_template_parm_no_parms)
1287 << SourceRange(Params->getLAngleLoc(), Params->getRAngleLoc());
1288 Param->setInvalidDecl();
1291 // C++0x [temp.param]p9:
1292 // A default template-argument may be specified for any kind of
1293 // template-parameter that is not a template parameter pack.
1294 if (IsParameterPack && !Default.isInvalid()) {
1295 Diag(EqualLoc, diag::err_template_param_pack_default_arg);
1296 Default = ParsedTemplateArgument();
1299 if (!Default.isInvalid()) {
1300 // Check only that we have a template template argument. We don't want to
1301 // try to check well-formedness now, because our template template parameter
1302 // might have dependent types in its template parameters, which we wouldn't
1303 // be able to match now.
1305 // If none of the template template parameter's template arguments mention
1306 // other template parameters, we could actually perform more checking here.
1307 // However, it isn't worth doing.
1308 TemplateArgumentLoc DefaultArg = translateTemplateArgument(*this, Default);
1309 if (DefaultArg.getArgument().getAsTemplate().isNull()) {
1310 Diag(DefaultArg.getLocation(), diag::err_template_arg_not_valid_template)
1311 << DefaultArg.getSourceRange();
1315 // Check for unexpanded parameter packs.
1316 if (DiagnoseUnexpandedParameterPack(DefaultArg.getLocation(),
1317 DefaultArg.getArgument().getAsTemplate(),
1318 UPPC_DefaultArgument))
1321 Param->setDefaultArgument(Context, DefaultArg);
1327 /// ActOnTemplateParameterList - Builds a TemplateParameterList, optionally
1328 /// constrained by RequiresClause, that contains the template parameters in
1330 TemplateParameterList *
1331 Sema::ActOnTemplateParameterList(unsigned Depth,
1332 SourceLocation ExportLoc,
1333 SourceLocation TemplateLoc,
1334 SourceLocation LAngleLoc,
1335 ArrayRef<NamedDecl *> Params,
1336 SourceLocation RAngleLoc,
1337 Expr *RequiresClause) {
1338 if (ExportLoc.isValid())
1339 Diag(ExportLoc, diag::warn_template_export_unsupported);
1341 return TemplateParameterList::Create(
1342 Context, TemplateLoc, LAngleLoc,
1343 llvm::makeArrayRef(Params.data(), Params.size()),
1344 RAngleLoc, RequiresClause);
1347 static void SetNestedNameSpecifier(Sema &S, TagDecl *T,
1348 const CXXScopeSpec &SS) {
1350 T->setQualifierInfo(SS.getWithLocInContext(S.Context));
1353 DeclResult Sema::CheckClassTemplate(
1354 Scope *S, unsigned TagSpec, TagUseKind TUK, SourceLocation KWLoc,
1355 CXXScopeSpec &SS, IdentifierInfo *Name, SourceLocation NameLoc,
1356 const ParsedAttributesView &Attr, TemplateParameterList *TemplateParams,
1357 AccessSpecifier AS, SourceLocation ModulePrivateLoc,
1358 SourceLocation FriendLoc, unsigned NumOuterTemplateParamLists,
1359 TemplateParameterList **OuterTemplateParamLists, SkipBodyInfo *SkipBody) {
1360 assert(TemplateParams && TemplateParams->size() > 0 &&
1361 "No template parameters");
1362 assert(TUK != TUK_Reference && "Can only declare or define class templates");
1363 bool Invalid = false;
1365 // Check that we can declare a template here.
1366 if (CheckTemplateDeclScope(S, TemplateParams))
1369 TagTypeKind Kind = TypeWithKeyword::getTagTypeKindForTypeSpec(TagSpec);
1370 assert(Kind != TTK_Enum && "can't build template of enumerated type");
1372 // There is no such thing as an unnamed class template.
1374 Diag(KWLoc, diag::err_template_unnamed_class);
1378 // Find any previous declaration with this name. For a friend with no
1379 // scope explicitly specified, we only look for tag declarations (per
1380 // C++11 [basic.lookup.elab]p2).
1381 DeclContext *SemanticContext;
1382 LookupResult Previous(*this, Name, NameLoc,
1383 (SS.isEmpty() && TUK == TUK_Friend)
1384 ? LookupTagName : LookupOrdinaryName,
1385 forRedeclarationInCurContext());
1386 if (SS.isNotEmpty() && !SS.isInvalid()) {
1387 SemanticContext = computeDeclContext(SS, true);
1388 if (!SemanticContext) {
1389 // FIXME: Horrible, horrible hack! We can't currently represent this
1390 // in the AST, and historically we have just ignored such friend
1391 // class templates, so don't complain here.
1392 Diag(NameLoc, TUK == TUK_Friend
1393 ? diag::warn_template_qualified_friend_ignored
1394 : diag::err_template_qualified_declarator_no_match)
1395 << SS.getScopeRep() << SS.getRange();
1396 return TUK != TUK_Friend;
1399 if (RequireCompleteDeclContext(SS, SemanticContext))
1402 // If we're adding a template to a dependent context, we may need to
1403 // rebuilding some of the types used within the template parameter list,
1404 // now that we know what the current instantiation is.
1405 if (SemanticContext->isDependentContext()) {
1406 ContextRAII SavedContext(*this, SemanticContext);
1407 if (RebuildTemplateParamsInCurrentInstantiation(TemplateParams))
1409 } else if (TUK != TUK_Friend && TUK != TUK_Reference)
1410 diagnoseQualifiedDeclaration(SS, SemanticContext, Name, NameLoc, false);
1412 LookupQualifiedName(Previous, SemanticContext);
1414 SemanticContext = CurContext;
1416 // C++14 [class.mem]p14:
1417 // If T is the name of a class, then each of the following shall have a
1418 // name different from T:
1419 // -- every member template of class T
1420 if (TUK != TUK_Friend &&
1421 DiagnoseClassNameShadow(SemanticContext,
1422 DeclarationNameInfo(Name, NameLoc)))
1425 LookupName(Previous, S);
1428 if (Previous.isAmbiguous())
1431 NamedDecl *PrevDecl = nullptr;
1432 if (Previous.begin() != Previous.end())
1433 PrevDecl = (*Previous.begin())->getUnderlyingDecl();
1435 if (PrevDecl && PrevDecl->isTemplateParameter()) {
1436 // Maybe we will complain about the shadowed template parameter.
1437 DiagnoseTemplateParameterShadow(NameLoc, PrevDecl);
1438 // Just pretend that we didn't see the previous declaration.
1442 // If there is a previous declaration with the same name, check
1443 // whether this is a valid redeclaration.
1444 ClassTemplateDecl *PrevClassTemplate =
1445 dyn_cast_or_null<ClassTemplateDecl>(PrevDecl);
1447 // We may have found the injected-class-name of a class template,
1448 // class template partial specialization, or class template specialization.
1449 // In these cases, grab the template that is being defined or specialized.
1450 if (!PrevClassTemplate && PrevDecl && isa<CXXRecordDecl>(PrevDecl) &&
1451 cast<CXXRecordDecl>(PrevDecl)->isInjectedClassName()) {
1452 PrevDecl = cast<CXXRecordDecl>(PrevDecl->getDeclContext());
1454 = cast<CXXRecordDecl>(PrevDecl)->getDescribedClassTemplate();
1455 if (!PrevClassTemplate && isa<ClassTemplateSpecializationDecl>(PrevDecl)) {
1457 = cast<ClassTemplateSpecializationDecl>(PrevDecl)
1458 ->getSpecializedTemplate();
1462 if (TUK == TUK_Friend) {
1463 // C++ [namespace.memdef]p3:
1464 // [...] When looking for a prior declaration of a class or a function
1465 // declared as a friend, and when the name of the friend class or
1466 // function is neither a qualified name nor a template-id, scopes outside
1467 // the innermost enclosing namespace scope are not considered.
1469 DeclContext *OutermostContext = CurContext;
1470 while (!OutermostContext->isFileContext())
1471 OutermostContext = OutermostContext->getLookupParent();
1474 (OutermostContext->Equals(PrevDecl->getDeclContext()) ||
1475 OutermostContext->Encloses(PrevDecl->getDeclContext()))) {
1476 SemanticContext = PrevDecl->getDeclContext();
1478 // Declarations in outer scopes don't matter. However, the outermost
1479 // context we computed is the semantic context for our new
1481 PrevDecl = PrevClassTemplate = nullptr;
1482 SemanticContext = OutermostContext;
1484 // Check that the chosen semantic context doesn't already contain a
1485 // declaration of this name as a non-tag type.
1486 Previous.clear(LookupOrdinaryName);
1487 DeclContext *LookupContext = SemanticContext;
1488 while (LookupContext->isTransparentContext())
1489 LookupContext = LookupContext->getLookupParent();
1490 LookupQualifiedName(Previous, LookupContext);
1492 if (Previous.isAmbiguous())
1495 if (Previous.begin() != Previous.end())
1496 PrevDecl = (*Previous.begin())->getUnderlyingDecl();
1499 } else if (PrevDecl &&
1500 !isDeclInScope(Previous.getRepresentativeDecl(), SemanticContext,
1502 PrevDecl = PrevClassTemplate = nullptr;
1504 if (auto *Shadow = dyn_cast_or_null<UsingShadowDecl>(
1505 PrevDecl ? Previous.getRepresentativeDecl() : nullptr)) {
1507 !(PrevClassTemplate &&
1508 PrevClassTemplate->getDeclContext()->getRedeclContext()->Equals(
1509 SemanticContext->getRedeclContext()))) {
1510 Diag(KWLoc, diag::err_using_decl_conflict_reverse);
1511 Diag(Shadow->getTargetDecl()->getLocation(),
1512 diag::note_using_decl_target);
1513 Diag(Shadow->getUsingDecl()->getLocation(), diag::note_using_decl) << 0;
1514 // Recover by ignoring the old declaration.
1515 PrevDecl = PrevClassTemplate = nullptr;
1519 // TODO Memory management; associated constraints are not always stored.
1520 Expr *const CurAC = formAssociatedConstraints(TemplateParams, nullptr);
1522 if (PrevClassTemplate) {
1523 // Ensure that the template parameter lists are compatible. Skip this check
1524 // for a friend in a dependent context: the template parameter list itself
1525 // could be dependent.
1526 if (!(TUK == TUK_Friend && CurContext->isDependentContext()) &&
1527 !TemplateParameterListsAreEqual(TemplateParams,
1528 PrevClassTemplate->getTemplateParameters(),
1533 // Check for matching associated constraints on redeclarations.
1534 const Expr *const PrevAC = PrevClassTemplate->getAssociatedConstraints();
1535 const bool RedeclACMismatch = [&] {
1536 if (!(CurAC || PrevAC))
1537 return false; // Nothing to check; no mismatch.
1538 if (CurAC && PrevAC) {
1539 llvm::FoldingSetNodeID CurACInfo, PrevACInfo;
1540 CurAC->Profile(CurACInfo, Context, /*Canonical=*/true);
1541 PrevAC->Profile(PrevACInfo, Context, /*Canonical=*/true);
1542 if (CurACInfo == PrevACInfo)
1543 return false; // All good; no mismatch.
1548 if (RedeclACMismatch) {
1549 Diag(CurAC ? CurAC->getBeginLoc() : NameLoc,
1550 diag::err_template_different_associated_constraints);
1551 Diag(PrevAC ? PrevAC->getBeginLoc() : PrevClassTemplate->getLocation(),
1552 diag::note_template_prev_declaration)
1553 << /*declaration*/ 0;
1557 // C++ [temp.class]p4:
1558 // In a redeclaration, partial specialization, explicit
1559 // specialization or explicit instantiation of a class template,
1560 // the class-key shall agree in kind with the original class
1561 // template declaration (7.1.5.3).
1562 RecordDecl *PrevRecordDecl = PrevClassTemplate->getTemplatedDecl();
1563 if (!isAcceptableTagRedeclaration(PrevRecordDecl, Kind,
1564 TUK == TUK_Definition, KWLoc, Name)) {
1565 Diag(KWLoc, diag::err_use_with_wrong_tag)
1567 << FixItHint::CreateReplacement(KWLoc, PrevRecordDecl->getKindName());
1568 Diag(PrevRecordDecl->getLocation(), diag::note_previous_use);
1569 Kind = PrevRecordDecl->getTagKind();
1572 // Check for redefinition of this class template.
1573 if (TUK == TUK_Definition) {
1574 if (TagDecl *Def = PrevRecordDecl->getDefinition()) {
1575 // If we have a prior definition that is not visible, treat this as
1576 // simply making that previous definition visible.
1577 NamedDecl *Hidden = nullptr;
1578 if (SkipBody && !hasVisibleDefinition(Def, &Hidden)) {
1579 SkipBody->ShouldSkip = true;
1580 SkipBody->Previous = Def;
1581 auto *Tmpl = cast<CXXRecordDecl>(Hidden)->getDescribedClassTemplate();
1582 assert(Tmpl && "original definition of a class template is not a "
1584 makeMergedDefinitionVisible(Hidden);
1585 makeMergedDefinitionVisible(Tmpl);
1587 Diag(NameLoc, diag::err_redefinition) << Name;
1588 Diag(Def->getLocation(), diag::note_previous_definition);
1589 // FIXME: Would it make sense to try to "forget" the previous
1590 // definition, as part of error recovery?
1595 } else if (PrevDecl) {
1597 // A class template shall not have the same name as any other
1598 // template, class, function, object, enumeration, enumerator,
1599 // namespace, or type in the same scope (3.3), except as specified
1601 Diag(NameLoc, diag::err_redefinition_different_kind) << Name;
1602 Diag(PrevDecl->getLocation(), diag::note_previous_definition);
1606 // Check the template parameter list of this declaration, possibly
1607 // merging in the template parameter list from the previous class
1608 // template declaration. Skip this check for a friend in a dependent
1609 // context, because the template parameter list might be dependent.
1610 if (!(TUK == TUK_Friend && CurContext->isDependentContext()) &&
1611 CheckTemplateParameterList(
1614 ? PrevClassTemplate->getMostRecentDecl()->getTemplateParameters()
1616 (SS.isSet() && SemanticContext && SemanticContext->isRecord() &&
1617 SemanticContext->isDependentContext())
1618 ? TPC_ClassTemplateMember
1619 : TUK == TUK_Friend ? TPC_FriendClassTemplate : TPC_ClassTemplate,
1624 // If the name of the template was qualified, we must be defining the
1625 // template out-of-line.
1626 if (!SS.isInvalid() && !Invalid && !PrevClassTemplate) {
1627 Diag(NameLoc, TUK == TUK_Friend ? diag::err_friend_decl_does_not_match
1628 : diag::err_member_decl_does_not_match)
1629 << Name << SemanticContext << /*IsDefinition*/true << SS.getRange();
1634 // If this is a templated friend in a dependent context we should not put it
1635 // on the redecl chain. In some cases, the templated friend can be the most
1636 // recent declaration tricking the template instantiator to make substitutions
1638 // FIXME: Figure out how to combine with shouldLinkDependentDeclWithPrevious
1639 bool ShouldAddRedecl
1640 = !(TUK == TUK_Friend && CurContext->isDependentContext());
1642 CXXRecordDecl *NewClass =
1643 CXXRecordDecl::Create(Context, Kind, SemanticContext, KWLoc, NameLoc, Name,
1644 PrevClassTemplate && ShouldAddRedecl ?
1645 PrevClassTemplate->getTemplatedDecl() : nullptr,
1646 /*DelayTypeCreation=*/true);
1647 SetNestedNameSpecifier(*this, NewClass, SS);
1648 if (NumOuterTemplateParamLists > 0)
1649 NewClass->setTemplateParameterListsInfo(
1650 Context, llvm::makeArrayRef(OuterTemplateParamLists,
1651 NumOuterTemplateParamLists));
1653 // Add alignment attributes if necessary; these attributes are checked when
1654 // the ASTContext lays out the structure.
1655 if (TUK == TUK_Definition && (!SkipBody || !SkipBody->ShouldSkip)) {
1656 AddAlignmentAttributesForRecord(NewClass);
1657 AddMsStructLayoutForRecord(NewClass);
1660 // Attach the associated constraints when the declaration will not be part of
1662 Expr *const ACtoAttach =
1663 PrevClassTemplate && ShouldAddRedecl ? nullptr : CurAC;
1665 ClassTemplateDecl *NewTemplate
1666 = ClassTemplateDecl::Create(Context, SemanticContext, NameLoc,
1667 DeclarationName(Name), TemplateParams,
1668 NewClass, ACtoAttach);
1670 if (ShouldAddRedecl)
1671 NewTemplate->setPreviousDecl(PrevClassTemplate);
1673 NewClass->setDescribedClassTemplate(NewTemplate);
1675 if (ModulePrivateLoc.isValid())
1676 NewTemplate->setModulePrivate();
1678 // Build the type for the class template declaration now.
1679 QualType T = NewTemplate->getInjectedClassNameSpecialization();
1680 T = Context.getInjectedClassNameType(NewClass, T);
1681 assert(T->isDependentType() && "Class template type is not dependent?");
1684 // If we are providing an explicit specialization of a member that is a
1685 // class template, make a note of that.
1686 if (PrevClassTemplate &&
1687 PrevClassTemplate->getInstantiatedFromMemberTemplate())
1688 PrevClassTemplate->setMemberSpecialization();
1690 // Set the access specifier.
1691 if (!Invalid && TUK != TUK_Friend && NewTemplate->getDeclContext()->isRecord())
1692 SetMemberAccessSpecifier(NewTemplate, PrevClassTemplate, AS);
1694 // Set the lexical context of these templates
1695 NewClass->setLexicalDeclContext(CurContext);
1696 NewTemplate->setLexicalDeclContext(CurContext);
1698 if (TUK == TUK_Definition && (!SkipBody || !SkipBody->ShouldSkip))
1699 NewClass->startDefinition();
1701 ProcessDeclAttributeList(S, NewClass, Attr);
1703 if (PrevClassTemplate)
1704 mergeDeclAttributes(NewClass, PrevClassTemplate->getTemplatedDecl());
1706 AddPushedVisibilityAttribute(NewClass);
1708 if (TUK != TUK_Friend) {
1709 // Per C++ [basic.scope.temp]p2, skip the template parameter scopes.
1711 while ((Outer->getFlags() & Scope::TemplateParamScope) != 0)
1712 Outer = Outer->getParent();
1713 PushOnScopeChains(NewTemplate, Outer);
1715 if (PrevClassTemplate && PrevClassTemplate->getAccess() != AS_none) {
1716 NewTemplate->setAccess(PrevClassTemplate->getAccess());
1717 NewClass->setAccess(PrevClassTemplate->getAccess());
1720 NewTemplate->setObjectOfFriendDecl();
1722 // Friend templates are visible in fairly strange ways.
1723 if (!CurContext->isDependentContext()) {
1724 DeclContext *DC = SemanticContext->getRedeclContext();
1725 DC->makeDeclVisibleInContext(NewTemplate);
1726 if (Scope *EnclosingScope = getScopeForDeclContext(S, DC))
1727 PushOnScopeChains(NewTemplate, EnclosingScope,
1728 /* AddToContext = */ false);
1731 FriendDecl *Friend = FriendDecl::Create(
1732 Context, CurContext, NewClass->getLocation(), NewTemplate, FriendLoc);
1733 Friend->setAccess(AS_public);
1734 CurContext->addDecl(Friend);
1737 if (PrevClassTemplate)
1738 CheckRedeclarationModuleOwnership(NewTemplate, PrevClassTemplate);
1741 NewTemplate->setInvalidDecl();
1742 NewClass->setInvalidDecl();
1745 ActOnDocumentableDecl(NewTemplate);
1747 if (SkipBody && SkipBody->ShouldSkip)
1748 return SkipBody->Previous;
1754 /// Tree transform to "extract" a transformed type from a class template's
1755 /// constructor to a deduction guide.
1756 class ExtractTypeForDeductionGuide
1757 : public TreeTransform<ExtractTypeForDeductionGuide> {
1759 typedef TreeTransform<ExtractTypeForDeductionGuide> Base;
1760 ExtractTypeForDeductionGuide(Sema &SemaRef) : Base(SemaRef) {}
1762 TypeSourceInfo *transform(TypeSourceInfo *TSI) { return TransformType(TSI); }
1764 QualType TransformTypedefType(TypeLocBuilder &TLB, TypedefTypeLoc TL) {
1765 return TransformType(
1767 TL.getTypedefNameDecl()->getTypeSourceInfo()->getTypeLoc());
1771 /// Transform to convert portions of a constructor declaration into the
1772 /// corresponding deduction guide, per C++1z [over.match.class.deduct]p1.
1773 struct ConvertConstructorToDeductionGuideTransform {
1774 ConvertConstructorToDeductionGuideTransform(Sema &S,
1775 ClassTemplateDecl *Template)
1776 : SemaRef(S), Template(Template) {}
1779 ClassTemplateDecl *Template;
1781 DeclContext *DC = Template->getDeclContext();
1782 CXXRecordDecl *Primary = Template->getTemplatedDecl();
1783 DeclarationName DeductionGuideName =
1784 SemaRef.Context.DeclarationNames.getCXXDeductionGuideName(Template);
1786 QualType DeducedType = SemaRef.Context.getTypeDeclType(Primary);
1788 // Index adjustment to apply to convert depth-1 template parameters into
1789 // depth-0 template parameters.
1790 unsigned Depth1IndexAdjustment = Template->getTemplateParameters()->size();
1792 /// Transform a constructor declaration into a deduction guide.
1793 NamedDecl *transformConstructor(FunctionTemplateDecl *FTD,
1794 CXXConstructorDecl *CD) {
1795 SmallVector<TemplateArgument, 16> SubstArgs;
1797 LocalInstantiationScope Scope(SemaRef);
1799 // C++ [over.match.class.deduct]p1:
1800 // -- For each constructor of the class template designated by the
1801 // template-name, a function template with the following properties:
1803 // -- The template parameters are the template parameters of the class
1804 // template followed by the template parameters (including default
1805 // template arguments) of the constructor, if any.
1806 TemplateParameterList *TemplateParams = Template->getTemplateParameters();
1808 TemplateParameterList *InnerParams = FTD->getTemplateParameters();
1809 SmallVector<NamedDecl *, 16> AllParams;
1810 AllParams.reserve(TemplateParams->size() + InnerParams->size());
1811 AllParams.insert(AllParams.begin(),
1812 TemplateParams->begin(), TemplateParams->end());
1813 SubstArgs.reserve(InnerParams->size());
1815 // Later template parameters could refer to earlier ones, so build up
1816 // a list of substituted template arguments as we go.
1817 for (NamedDecl *Param : *InnerParams) {
1818 MultiLevelTemplateArgumentList Args;
1819 Args.addOuterTemplateArguments(SubstArgs);
1820 Args.addOuterRetainedLevel();
1821 NamedDecl *NewParam = transformTemplateParameter(Param, Args);
1824 AllParams.push_back(NewParam);
1825 SubstArgs.push_back(SemaRef.Context.getCanonicalTemplateArgument(
1826 SemaRef.Context.getInjectedTemplateArg(NewParam)));
1828 TemplateParams = TemplateParameterList::Create(
1829 SemaRef.Context, InnerParams->getTemplateLoc(),
1830 InnerParams->getLAngleLoc(), AllParams, InnerParams->getRAngleLoc(),
1831 /*FIXME: RequiresClause*/ nullptr);
1834 // If we built a new template-parameter-list, track that we need to
1835 // substitute references to the old parameters into references to the
1837 MultiLevelTemplateArgumentList Args;
1839 Args.addOuterTemplateArguments(SubstArgs);
1840 Args.addOuterRetainedLevel();
1843 FunctionProtoTypeLoc FPTL = CD->getTypeSourceInfo()->getTypeLoc()
1844 .getAsAdjusted<FunctionProtoTypeLoc>();
1845 assert(FPTL && "no prototype for constructor declaration");
1847 // Transform the type of the function, adjusting the return type and
1848 // replacing references to the old parameters with references to the
1851 SmallVector<ParmVarDecl*, 8> Params;
1852 QualType NewType = transformFunctionProtoType(TLB, FPTL, Params, Args);
1853 if (NewType.isNull())
1855 TypeSourceInfo *NewTInfo = TLB.getTypeSourceInfo(SemaRef.Context, NewType);
1857 return buildDeductionGuide(TemplateParams, CD->getExplicitSpecifier(),
1858 NewTInfo, CD->getBeginLoc(), CD->getLocation(),
1862 /// Build a deduction guide with the specified parameter types.
1863 NamedDecl *buildSimpleDeductionGuide(MutableArrayRef<QualType> ParamTypes) {
1864 SourceLocation Loc = Template->getLocation();
1866 // Build the requested type.
1867 FunctionProtoType::ExtProtoInfo EPI;
1868 EPI.HasTrailingReturn = true;
1869 QualType Result = SemaRef.BuildFunctionType(DeducedType, ParamTypes, Loc,
1870 DeductionGuideName, EPI);
1871 TypeSourceInfo *TSI = SemaRef.Context.getTrivialTypeSourceInfo(Result, Loc);
1873 FunctionProtoTypeLoc FPTL =
1874 TSI->getTypeLoc().castAs<FunctionProtoTypeLoc>();
1876 // Build the parameters, needed during deduction / substitution.
1877 SmallVector<ParmVarDecl*, 4> Params;
1878 for (auto T : ParamTypes) {
1879 ParmVarDecl *NewParam = ParmVarDecl::Create(
1880 SemaRef.Context, DC, Loc, Loc, nullptr, T,
1881 SemaRef.Context.getTrivialTypeSourceInfo(T, Loc), SC_None, nullptr);
1882 NewParam->setScopeInfo(0, Params.size());
1883 FPTL.setParam(Params.size(), NewParam);
1884 Params.push_back(NewParam);
1887 return buildDeductionGuide(Template->getTemplateParameters(),
1888 ExplicitSpecifier(), TSI, Loc, Loc, Loc);
1892 /// Transform a constructor template parameter into a deduction guide template
1893 /// parameter, rebuilding any internal references to earlier parameters and
1894 /// renumbering as we go.
1895 NamedDecl *transformTemplateParameter(NamedDecl *TemplateParam,
1896 MultiLevelTemplateArgumentList &Args) {
1897 if (auto *TTP = dyn_cast<TemplateTypeParmDecl>(TemplateParam)) {
1898 // TemplateTypeParmDecl's index cannot be changed after creation, so
1899 // substitute it directly.
1900 auto *NewTTP = TemplateTypeParmDecl::Create(
1901 SemaRef.Context, DC, TTP->getBeginLoc(), TTP->getLocation(),
1902 /*Depth*/ 0, Depth1IndexAdjustment + TTP->getIndex(),
1903 TTP->getIdentifier(), TTP->wasDeclaredWithTypename(),
1904 TTP->isParameterPack());
1905 if (TTP->hasDefaultArgument()) {
1906 TypeSourceInfo *InstantiatedDefaultArg =
1907 SemaRef.SubstType(TTP->getDefaultArgumentInfo(), Args,
1908 TTP->getDefaultArgumentLoc(), TTP->getDeclName());
1909 if (InstantiatedDefaultArg)
1910 NewTTP->setDefaultArgument(InstantiatedDefaultArg);
1912 SemaRef.CurrentInstantiationScope->InstantiatedLocal(TemplateParam,
1917 if (auto *TTP = dyn_cast<TemplateTemplateParmDecl>(TemplateParam))
1918 return transformTemplateParameterImpl(TTP, Args);
1920 return transformTemplateParameterImpl(
1921 cast<NonTypeTemplateParmDecl>(TemplateParam), Args);
1923 template<typename TemplateParmDecl>
1925 transformTemplateParameterImpl(TemplateParmDecl *OldParam,
1926 MultiLevelTemplateArgumentList &Args) {
1927 // Ask the template instantiator to do the heavy lifting for us, then adjust
1928 // the index of the parameter once it's done.
1930 cast_or_null<TemplateParmDecl>(SemaRef.SubstDecl(OldParam, DC, Args));
1931 assert(NewParam->getDepth() == 0 && "unexpected template param depth");
1932 NewParam->setPosition(NewParam->getPosition() + Depth1IndexAdjustment);
1936 QualType transformFunctionProtoType(TypeLocBuilder &TLB,
1937 FunctionProtoTypeLoc TL,
1938 SmallVectorImpl<ParmVarDecl*> &Params,
1939 MultiLevelTemplateArgumentList &Args) {
1940 SmallVector<QualType, 4> ParamTypes;
1941 const FunctionProtoType *T = TL.getTypePtr();
1943 // -- The types of the function parameters are those of the constructor.
1944 for (auto *OldParam : TL.getParams()) {
1945 ParmVarDecl *NewParam = transformFunctionTypeParam(OldParam, Args);
1948 ParamTypes.push_back(NewParam->getType());
1949 Params.push_back(NewParam);
1952 // -- The return type is the class template specialization designated by
1953 // the template-name and template arguments corresponding to the
1954 // template parameters obtained from the class template.
1956 // We use the injected-class-name type of the primary template instead.
1957 // This has the convenient property that it is different from any type that
1958 // the user can write in a deduction-guide (because they cannot enter the
1959 // context of the template), so implicit deduction guides can never collide
1960 // with explicit ones.
1961 QualType ReturnType = DeducedType;
1962 TLB.pushTypeSpec(ReturnType).setNameLoc(Primary->getLocation());
1964 // Resolving a wording defect, we also inherit the variadicness of the
1966 FunctionProtoType::ExtProtoInfo EPI;
1967 EPI.Variadic = T->isVariadic();
1968 EPI.HasTrailingReturn = true;
1970 QualType Result = SemaRef.BuildFunctionType(
1971 ReturnType, ParamTypes, TL.getBeginLoc(), DeductionGuideName, EPI);
1972 if (Result.isNull())
1975 FunctionProtoTypeLoc NewTL = TLB.push<FunctionProtoTypeLoc>(Result);
1976 NewTL.setLocalRangeBegin(TL.getLocalRangeBegin());
1977 NewTL.setLParenLoc(TL.getLParenLoc());
1978 NewTL.setRParenLoc(TL.getRParenLoc());
1979 NewTL.setExceptionSpecRange(SourceRange());
1980 NewTL.setLocalRangeEnd(TL.getLocalRangeEnd());
1981 for (unsigned I = 0, E = NewTL.getNumParams(); I != E; ++I)
1982 NewTL.setParam(I, Params[I]);
1988 transformFunctionTypeParam(ParmVarDecl *OldParam,
1989 MultiLevelTemplateArgumentList &Args) {
1990 TypeSourceInfo *OldDI = OldParam->getTypeSourceInfo();
1991 TypeSourceInfo *NewDI;
1992 if (auto PackTL = OldDI->getTypeLoc().getAs<PackExpansionTypeLoc>()) {
1993 // Expand out the one and only element in each inner pack.
1994 Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, 0);
1996 SemaRef.SubstType(PackTL.getPatternLoc(), Args,
1997 OldParam->getLocation(), OldParam->getDeclName());
1998 if (!NewDI) return nullptr;
2000 SemaRef.CheckPackExpansion(NewDI, PackTL.getEllipsisLoc(),
2001 PackTL.getTypePtr()->getNumExpansions());
2003 NewDI = SemaRef.SubstType(OldDI, Args, OldParam->getLocation(),
2004 OldParam->getDeclName());
2008 // Extract the type. This (for instance) replaces references to typedef
2009 // members of the current instantiations with the definitions of those
2010 // typedefs, avoiding triggering instantiation of the deduced type during
2012 NewDI = ExtractTypeForDeductionGuide(SemaRef).transform(NewDI);
2014 // Resolving a wording defect, we also inherit default arguments from the
2016 ExprResult NewDefArg;
2017 if (OldParam->hasDefaultArg()) {
2018 NewDefArg = SemaRef.SubstExpr(OldParam->getDefaultArg(), Args);
2019 if (NewDefArg.isInvalid())
2023 ParmVarDecl *NewParam = ParmVarDecl::Create(SemaRef.Context, DC,
2024 OldParam->getInnerLocStart(),
2025 OldParam->getLocation(),
2026 OldParam->getIdentifier(),
2029 OldParam->getStorageClass(),
2031 NewParam->setScopeInfo(OldParam->getFunctionScopeDepth(),
2032 OldParam->getFunctionScopeIndex());
2033 SemaRef.CurrentInstantiationScope->InstantiatedLocal(OldParam, NewParam);
2037 NamedDecl *buildDeductionGuide(TemplateParameterList *TemplateParams,
2038 ExplicitSpecifier ES, TypeSourceInfo *TInfo,
2039 SourceLocation LocStart, SourceLocation Loc,
2040 SourceLocation LocEnd) {
2041 DeclarationNameInfo Name(DeductionGuideName, Loc);
2042 ArrayRef<ParmVarDecl *> Params =
2043 TInfo->getTypeLoc().castAs<FunctionProtoTypeLoc>().getParams();
2045 // Build the implicit deduction guide template.
2047 CXXDeductionGuideDecl::Create(SemaRef.Context, DC, LocStart, ES, Name,
2048 TInfo->getType(), TInfo, LocEnd);
2049 Guide->setImplicit();
2050 Guide->setParams(Params);
2052 for (auto *Param : Params)
2053 Param->setDeclContext(Guide);
2055 auto *GuideTemplate = FunctionTemplateDecl::Create(
2056 SemaRef.Context, DC, Loc, DeductionGuideName, TemplateParams, Guide);
2057 GuideTemplate->setImplicit();
2058 Guide->setDescribedFunctionTemplate(GuideTemplate);
2060 if (isa<CXXRecordDecl>(DC)) {
2061 Guide->setAccess(AS_public);
2062 GuideTemplate->setAccess(AS_public);
2065 DC->addDecl(GuideTemplate);
2066 return GuideTemplate;
2071 void Sema::DeclareImplicitDeductionGuides(TemplateDecl *Template,
2072 SourceLocation Loc) {
2073 if (CXXRecordDecl *DefRecord =
2074 cast<CXXRecordDecl>(Template->getTemplatedDecl())->getDefinition()) {
2075 TemplateDecl *DescribedTemplate = DefRecord->getDescribedClassTemplate();
2076 Template = DescribedTemplate ? DescribedTemplate : Template;
2079 DeclContext *DC = Template->getDeclContext();
2080 if (DC->isDependentContext())
2083 ConvertConstructorToDeductionGuideTransform Transform(
2084 *this, cast<ClassTemplateDecl>(Template));
2085 if (!isCompleteType(Loc, Transform.DeducedType))
2088 // Check whether we've already declared deduction guides for this template.
2089 // FIXME: Consider storing a flag on the template to indicate this.
2090 auto Existing = DC->lookup(Transform.DeductionGuideName);
2091 for (auto *D : Existing)
2092 if (D->isImplicit())
2095 // In case we were expanding a pack when we attempted to declare deduction
2096 // guides, turn off pack expansion for everything we're about to do.
2097 ArgumentPackSubstitutionIndexRAII SubstIndex(*this, -1);
2098 // Create a template instantiation record to track the "instantiation" of
2099 // constructors into deduction guides.
2100 // FIXME: Add a kind for this to give more meaningful diagnostics. But can
2101 // this substitution process actually fail?
2102 InstantiatingTemplate BuildingDeductionGuides(*this, Loc, Template);
2103 if (BuildingDeductionGuides.isInvalid())
2106 // Convert declared constructors into deduction guide templates.
2107 // FIXME: Skip constructors for which deduction must necessarily fail (those
2108 // for which some class template parameter without a default argument never
2109 // appears in a deduced context).
2110 bool AddedAny = false;
2111 for (NamedDecl *D : LookupConstructors(Transform.Primary)) {
2112 D = D->getUnderlyingDecl();
2113 if (D->isInvalidDecl() || D->isImplicit())
2115 D = cast<NamedDecl>(D->getCanonicalDecl());
2117 auto *FTD = dyn_cast<FunctionTemplateDecl>(D);
2119 dyn_cast_or_null<CXXConstructorDecl>(FTD ? FTD->getTemplatedDecl() : D);
2120 // Class-scope explicit specializations (MS extension) do not result in
2121 // deduction guides.
2122 if (!CD || (!FTD && CD->isFunctionTemplateSpecialization()))
2125 Transform.transformConstructor(FTD, CD);
2129 // C++17 [over.match.class.deduct]
2130 // -- If C is not defined or does not declare any constructors, an
2131 // additional function template derived as above from a hypothetical
2134 Transform.buildSimpleDeductionGuide(None);
2136 // -- An additional function template derived as above from a hypothetical
2137 // constructor C(C), called the copy deduction candidate.
2138 cast<CXXDeductionGuideDecl>(
2139 cast<FunctionTemplateDecl>(
2140 Transform.buildSimpleDeductionGuide(Transform.DeducedType))
2141 ->getTemplatedDecl())
2142 ->setIsCopyDeductionCandidate();
2145 /// Diagnose the presence of a default template argument on a
2146 /// template parameter, which is ill-formed in certain contexts.
2148 /// \returns true if the default template argument should be dropped.
2149 static bool DiagnoseDefaultTemplateArgument(Sema &S,
2150 Sema::TemplateParamListContext TPC,
2151 SourceLocation ParamLoc,
2152 SourceRange DefArgRange) {
2154 case Sema::TPC_ClassTemplate:
2155 case Sema::TPC_VarTemplate:
2156 case Sema::TPC_TypeAliasTemplate:
2159 case Sema::TPC_FunctionTemplate:
2160 case Sema::TPC_FriendFunctionTemplateDefinition:
2161 // C++ [temp.param]p9:
2162 // A default template-argument shall not be specified in a
2163 // function template declaration or a function template
2165 // If a friend function template declaration specifies a default
2166 // template-argument, that declaration shall be a definition and shall be
2167 // the only declaration of the function template in the translation unit.
2168 // (C++98/03 doesn't have this wording; see DR226).
2169 S.Diag(ParamLoc, S.getLangOpts().CPlusPlus11 ?
2170 diag::warn_cxx98_compat_template_parameter_default_in_function_template
2171 : diag::ext_template_parameter_default_in_function_template)
2175 case Sema::TPC_ClassTemplateMember:
2176 // C++0x [temp.param]p9:
2177 // A default template-argument shall not be specified in the
2178 // template-parameter-lists of the definition of a member of a
2179 // class template that appears outside of the member's class.
2180 S.Diag(ParamLoc, diag::err_template_parameter_default_template_member)
2184 case Sema::TPC_FriendClassTemplate:
2185 case Sema::TPC_FriendFunctionTemplate:
2186 // C++ [temp.param]p9:
2187 // A default template-argument shall not be specified in a
2188 // friend template declaration.
2189 S.Diag(ParamLoc, diag::err_template_parameter_default_friend_template)
2193 // FIXME: C++0x [temp.param]p9 allows default template-arguments
2194 // for friend function templates if there is only a single
2195 // declaration (and it is a definition). Strange!
2198 llvm_unreachable("Invalid TemplateParamListContext!");
2201 /// Check for unexpanded parameter packs within the template parameters
2202 /// of a template template parameter, recursively.
2203 static bool DiagnoseUnexpandedParameterPacks(Sema &S,
2204 TemplateTemplateParmDecl *TTP) {
2205 // A template template parameter which is a parameter pack is also a pack
2207 if (TTP->isParameterPack())
2210 TemplateParameterList *Params = TTP->getTemplateParameters();
2211 for (unsigned I = 0, N = Params->size(); I != N; ++I) {
2212 NamedDecl *P = Params->getParam(I);
2213 if (NonTypeTemplateParmDecl *NTTP = dyn_cast<NonTypeTemplateParmDecl>(P)) {
2214 if (!NTTP->isParameterPack() &&
2215 S.DiagnoseUnexpandedParameterPack(NTTP->getLocation(),
2216 NTTP->getTypeSourceInfo(),
2217 Sema::UPPC_NonTypeTemplateParameterType))
2223 if (TemplateTemplateParmDecl *InnerTTP
2224 = dyn_cast<TemplateTemplateParmDecl>(P))
2225 if (DiagnoseUnexpandedParameterPacks(S, InnerTTP))
2232 /// Checks the validity of a template parameter list, possibly
2233 /// considering the template parameter list from a previous
2236 /// If an "old" template parameter list is provided, it must be
2237 /// equivalent (per TemplateParameterListsAreEqual) to the "new"
2238 /// template parameter list.
2240 /// \param NewParams Template parameter list for a new template
2241 /// declaration. This template parameter list will be updated with any
2242 /// default arguments that are carried through from the previous
2243 /// template parameter list.
2245 /// \param OldParams If provided, template parameter list from a
2246 /// previous declaration of the same template. Default template
2247 /// arguments will be merged from the old template parameter list to
2248 /// the new template parameter list.
2250 /// \param TPC Describes the context in which we are checking the given
2251 /// template parameter list.
2253 /// \param SkipBody If we might have already made a prior merged definition
2254 /// of this template visible, the corresponding body-skipping information.
2255 /// Default argument redefinition is not an error when skipping such a body,
2256 /// because (under the ODR) we can assume the default arguments are the same
2257 /// as the prior merged definition.
2259 /// \returns true if an error occurred, false otherwise.
2260 bool Sema::CheckTemplateParameterList(TemplateParameterList *NewParams,
2261 TemplateParameterList *OldParams,
2262 TemplateParamListContext TPC,
2263 SkipBodyInfo *SkipBody) {
2264 bool Invalid = false;
2266 // C++ [temp.param]p10:
2267 // The set of default template-arguments available for use with a
2268 // template declaration or definition is obtained by merging the
2269 // default arguments from the definition (if in scope) and all
2270 // declarations in scope in the same way default function
2271 // arguments are (8.3.6).
2272 bool SawDefaultArgument = false;
2273 SourceLocation PreviousDefaultArgLoc;
2275 // Dummy initialization to avoid warnings.
2276 TemplateParameterList::iterator OldParam = NewParams->end();
2278 OldParam = OldParams->begin();
2280 bool RemoveDefaultArguments = false;
2281 for (TemplateParameterList::iterator NewParam = NewParams->begin(),
2282 NewParamEnd = NewParams->end();
2283 NewParam != NewParamEnd; ++NewParam) {
2284 // Variables used to diagnose redundant default arguments
2285 bool RedundantDefaultArg = false;
2286 SourceLocation OldDefaultLoc;
2287 SourceLocation NewDefaultLoc;
2289 // Variable used to diagnose missing default arguments
2290 bool MissingDefaultArg = false;
2292 // Variable used to diagnose non-final parameter packs
2293 bool SawParameterPack = false;
2295 if (TemplateTypeParmDecl *NewTypeParm
2296 = dyn_cast<TemplateTypeParmDecl>(*NewParam)) {
2297 // Check the presence of a default argument here.
2298 if (NewTypeParm->hasDefaultArgument() &&
2299 DiagnoseDefaultTemplateArgument(*this, TPC,
2300 NewTypeParm->getLocation(),
2301 NewTypeParm->getDefaultArgumentInfo()->getTypeLoc()
2303 NewTypeParm->removeDefaultArgument();
2305 // Merge default arguments for template type parameters.
2306 TemplateTypeParmDecl *OldTypeParm
2307 = OldParams? cast<TemplateTypeParmDecl>(*OldParam) : nullptr;
2308 if (NewTypeParm->isParameterPack()) {
2309 assert(!NewTypeParm->hasDefaultArgument() &&
2310 "Parameter packs can't have a default argument!");
2311 SawParameterPack = true;
2312 } else if (OldTypeParm && hasVisibleDefaultArgument(OldTypeParm) &&
2313 NewTypeParm->hasDefaultArgument() &&
2314 (!SkipBody || !SkipBody->ShouldSkip)) {
2315 OldDefaultLoc = OldTypeParm->getDefaultArgumentLoc();
2316 NewDefaultLoc = NewTypeParm->getDefaultArgumentLoc();
2317 SawDefaultArgument = true;
2318 RedundantDefaultArg = true;
2319 PreviousDefaultArgLoc = NewDefaultLoc;
2320 } else if (OldTypeParm && OldTypeParm->hasDefaultArgument()) {
2321 // Merge the default argument from the old declaration to the
2323 NewTypeParm->setInheritedDefaultArgument(Context, OldTypeParm);
2324 PreviousDefaultArgLoc = OldTypeParm->getDefaultArgumentLoc();
2325 } else if (NewTypeParm->hasDefaultArgument()) {
2326 SawDefaultArgument = true;
2327 PreviousDefaultArgLoc = NewTypeParm->getDefaultArgumentLoc();
2328 } else if (SawDefaultArgument)
2329 MissingDefaultArg = true;
2330 } else if (NonTypeTemplateParmDecl *NewNonTypeParm
2331 = dyn_cast<NonTypeTemplateParmDecl>(*NewParam)) {
2332 // Check for unexpanded parameter packs.
2333 if (!NewNonTypeParm->isParameterPack() &&
2334 DiagnoseUnexpandedParameterPack(NewNonTypeParm->getLocation(),
2335 NewNonTypeParm->getTypeSourceInfo(),
2336 UPPC_NonTypeTemplateParameterType)) {
2341 // Check the presence of a default argument here.
2342 if (NewNonTypeParm->hasDefaultArgument() &&
2343 DiagnoseDefaultTemplateArgument(*this, TPC,
2344 NewNonTypeParm->getLocation(),
2345 NewNonTypeParm->getDefaultArgument()->getSourceRange())) {
2346 NewNonTypeParm->removeDefaultArgument();
2349 // Merge default arguments for non-type template parameters
2350 NonTypeTemplateParmDecl *OldNonTypeParm
2351 = OldParams? cast<NonTypeTemplateParmDecl>(*OldParam) : nullptr;
2352 if (NewNonTypeParm->isParameterPack()) {
2353 assert(!NewNonTypeParm->hasDefaultArgument() &&
2354 "Parameter packs can't have a default argument!");
2355 if (!NewNonTypeParm->isPackExpansion())
2356 SawParameterPack = true;
2357 } else if (OldNonTypeParm && hasVisibleDefaultArgument(OldNonTypeParm) &&
2358 NewNonTypeParm->hasDefaultArgument() &&
2359 (!SkipBody || !SkipBody->ShouldSkip)) {
2360 OldDefaultLoc = OldNonTypeParm->getDefaultArgumentLoc();
2361 NewDefaultLoc = NewNonTypeParm->getDefaultArgumentLoc();
2362 SawDefaultArgument = true;
2363 RedundantDefaultArg = true;
2364 PreviousDefaultArgLoc = NewDefaultLoc;
2365 } else if (OldNonTypeParm && OldNonTypeParm->hasDefaultArgument()) {
2366 // Merge the default argument from the old declaration to the
2368 NewNonTypeParm->setInheritedDefaultArgument(Context, OldNonTypeParm);
2369 PreviousDefaultArgLoc = OldNonTypeParm->getDefaultArgumentLoc();
2370 } else if (NewNonTypeParm->hasDefaultArgument()) {
2371 SawDefaultArgument = true;
2372 PreviousDefaultArgLoc = NewNonTypeParm->getDefaultArgumentLoc();
2373 } else if (SawDefaultArgument)
2374 MissingDefaultArg = true;
2376 TemplateTemplateParmDecl *NewTemplateParm
2377 = cast<TemplateTemplateParmDecl>(*NewParam);
2379 // Check for unexpanded parameter packs, recursively.
2380 if (::DiagnoseUnexpandedParameterPacks(*this, NewTemplateParm)) {
2385 // Check the presence of a default argument here.
2386 if (NewTemplateParm->hasDefaultArgument() &&
2387 DiagnoseDefaultTemplateArgument(*this, TPC,
2388 NewTemplateParm->getLocation(),
2389 NewTemplateParm->getDefaultArgument().getSourceRange()))
2390 NewTemplateParm->removeDefaultArgument();
2392 // Merge default arguments for template template parameters
2393 TemplateTemplateParmDecl *OldTemplateParm
2394 = OldParams? cast<TemplateTemplateParmDecl>(*OldParam) : nullptr;
2395 if (NewTemplateParm->isParameterPack()) {
2396 assert(!NewTemplateParm->hasDefaultArgument() &&
2397 "Parameter packs can't have a default argument!");
2398 if (!NewTemplateParm->isPackExpansion())
2399 SawParameterPack = true;
2400 } else if (OldTemplateParm &&
2401 hasVisibleDefaultArgument(OldTemplateParm) &&
2402 NewTemplateParm->hasDefaultArgument() &&
2403 (!SkipBody || !SkipBody->ShouldSkip)) {
2404 OldDefaultLoc = OldTemplateParm->getDefaultArgument().getLocation();
2405 NewDefaultLoc = NewTemplateParm->getDefaultArgument().getLocation();
2406 SawDefaultArgument = true;
2407 RedundantDefaultArg = true;
2408 PreviousDefaultArgLoc = NewDefaultLoc;
2409 } else if (OldTemplateParm && OldTemplateParm->hasDefaultArgument()) {
2410 // Merge the default argument from the old declaration to the
2412 NewTemplateParm->setInheritedDefaultArgument(Context, OldTemplateParm);
2413 PreviousDefaultArgLoc
2414 = OldTemplateParm->getDefaultArgument().getLocation();
2415 } else if (NewTemplateParm->hasDefaultArgument()) {
2416 SawDefaultArgument = true;
2417 PreviousDefaultArgLoc
2418 = NewTemplateParm->getDefaultArgument().getLocation();
2419 } else if (SawDefaultArgument)
2420 MissingDefaultArg = true;
2423 // C++11 [temp.param]p11:
2424 // If a template parameter of a primary class template or alias template
2425 // is a template parameter pack, it shall be the last template parameter.
2426 if (SawParameterPack && (NewParam + 1) != NewParamEnd &&
2427 (TPC == TPC_ClassTemplate || TPC == TPC_VarTemplate ||
2428 TPC == TPC_TypeAliasTemplate)) {
2429 Diag((*NewParam)->getLocation(),
2430 diag::err_template_param_pack_must_be_last_template_parameter);
2434 if (RedundantDefaultArg) {
2435 // C++ [temp.param]p12:
2436 // A template-parameter shall not be given default arguments
2437 // by two different declarations in the same scope.
2438 Diag(NewDefaultLoc, diag::err_template_param_default_arg_redefinition);
2439 Diag(OldDefaultLoc, diag::note_template_param_prev_default_arg);
2441 } else if (MissingDefaultArg && TPC != TPC_FunctionTemplate) {
2442 // C++ [temp.param]p11:
2443 // If a template-parameter of a class template has a default
2444 // template-argument, each subsequent template-parameter shall either
2445 // have a default template-argument supplied or be a template parameter
2447 Diag((*NewParam)->getLocation(),
2448 diag::err_template_param_default_arg_missing);
2449 Diag(PreviousDefaultArgLoc, diag::note_template_param_prev_default_arg);
2451 RemoveDefaultArguments = true;
2454 // If we have an old template parameter list that we're merging
2455 // in, move on to the next parameter.
2460 // We were missing some default arguments at the end of the list, so remove
2461 // all of the default arguments.
2462 if (RemoveDefaultArguments) {
2463 for (TemplateParameterList::iterator NewParam = NewParams->begin(),
2464 NewParamEnd = NewParams->end();
2465 NewParam != NewParamEnd; ++NewParam) {
2466 if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(*NewParam))
2467 TTP->removeDefaultArgument();
2468 else if (NonTypeTemplateParmDecl *NTTP
2469 = dyn_cast<NonTypeTemplateParmDecl>(*NewParam))
2470 NTTP->removeDefaultArgument();
2472 cast<TemplateTemplateParmDecl>(*NewParam)->removeDefaultArgument();
2481 /// A class which looks for a use of a certain level of template
2483 struct DependencyChecker : RecursiveASTVisitor<DependencyChecker> {
2484 typedef RecursiveASTVisitor<DependencyChecker> super;
2488 // Whether we're looking for a use of a template parameter that makes the
2489 // overall construct type-dependent / a dependent type. This is strictly
2490 // best-effort for now; we may fail to match at all for a dependent type
2491 // in some cases if this is set.
2492 bool IgnoreNonTypeDependent;
2495 SourceLocation MatchLoc;
2497 DependencyChecker(unsigned Depth, bool IgnoreNonTypeDependent)
2498 : Depth(Depth), IgnoreNonTypeDependent(IgnoreNonTypeDependent),
2501 DependencyChecker(TemplateParameterList *Params, bool IgnoreNonTypeDependent)
2502 : IgnoreNonTypeDependent(IgnoreNonTypeDependent), Match(false) {
2503 NamedDecl *ND = Params->getParam(0);
2504 if (TemplateTypeParmDecl *PD = dyn_cast<TemplateTypeParmDecl>(ND)) {
2505 Depth = PD->getDepth();
2506 } else if (NonTypeTemplateParmDecl *PD =
2507 dyn_cast<NonTypeTemplateParmDecl>(ND)) {
2508 Depth = PD->getDepth();
2510 Depth = cast<TemplateTemplateParmDecl>(ND)->getDepth();
2514 bool Matches(unsigned ParmDepth, SourceLocation Loc = SourceLocation()) {
2515 if (ParmDepth >= Depth) {
2523 bool TraverseStmt(Stmt *S, DataRecursionQueue *Q = nullptr) {
2524 // Prune out non-type-dependent expressions if requested. This can
2525 // sometimes result in us failing to find a template parameter reference
2526 // (if a value-dependent expression creates a dependent type), but this
2527 // mode is best-effort only.
2528 if (auto *E = dyn_cast_or_null<Expr>(S))
2529 if (IgnoreNonTypeDependent && !E->isTypeDependent())
2531 return super::TraverseStmt(S, Q);
2534 bool TraverseTypeLoc(TypeLoc TL) {
2535 if (IgnoreNonTypeDependent && !TL.isNull() &&
2536 !TL.getType()->isDependentType())
2538 return super::TraverseTypeLoc(TL);
2541 bool VisitTemplateTypeParmTypeLoc(TemplateTypeParmTypeLoc TL) {
2542 return !Matches(TL.getTypePtr()->getDepth(), TL.getNameLoc());
2545 bool VisitTemplateTypeParmType(const TemplateTypeParmType *T) {
2546 // For a best-effort search, keep looking until we find a location.
2547 return IgnoreNonTypeDependent || !Matches(T->getDepth());
2550 bool TraverseTemplateName(TemplateName N) {
2551 if (TemplateTemplateParmDecl *PD =
2552 dyn_cast_or_null<TemplateTemplateParmDecl>(N.getAsTemplateDecl()))
2553 if (Matches(PD->getDepth()))
2555 return super::TraverseTemplateName(N);
2558 bool VisitDeclRefExpr(DeclRefExpr *E) {
2559 if (NonTypeTemplateParmDecl *PD =
2560 dyn_cast<NonTypeTemplateParmDecl>(E->getDecl()))
2561 if (Matches(PD->getDepth(), E->getExprLoc()))
2563 return super::VisitDeclRefExpr(E);
2566 bool VisitSubstTemplateTypeParmType(const SubstTemplateTypeParmType *T) {
2567 return TraverseType(T->getReplacementType());
2571 VisitSubstTemplateTypeParmPackType(const SubstTemplateTypeParmPackType *T) {
2572 return TraverseTemplateArgument(T->getArgumentPack());
2575 bool TraverseInjectedClassNameType(const InjectedClassNameType *T) {
2576 return TraverseType(T->getInjectedSpecializationType());
2579 } // end anonymous namespace
2581 /// Determines whether a given type depends on the given parameter
2584 DependsOnTemplateParameters(QualType T, TemplateParameterList *Params) {
2585 DependencyChecker Checker(Params, /*IgnoreNonTypeDependent*/false);
2586 Checker.TraverseType(T);
2587 return Checker.Match;
2590 // Find the source range corresponding to the named type in the given
2591 // nested-name-specifier, if any.
2592 static SourceRange getRangeOfTypeInNestedNameSpecifier(ASTContext &Context,
2594 const CXXScopeSpec &SS) {
2595 NestedNameSpecifierLoc NNSLoc(SS.getScopeRep(), SS.location_data());
2596 while (NestedNameSpecifier *NNS = NNSLoc.getNestedNameSpecifier()) {
2597 if (const Type *CurType = NNS->getAsType()) {
2598 if (Context.hasSameUnqualifiedType(T, QualType(CurType, 0)))
2599 return NNSLoc.getTypeLoc().getSourceRange();
2603 NNSLoc = NNSLoc.getPrefix();
2606 return SourceRange();
2609 /// Match the given template parameter lists to the given scope
2610 /// specifier, returning the template parameter list that applies to the
2613 /// \param DeclStartLoc the start of the declaration that has a scope
2614 /// specifier or a template parameter list.
2616 /// \param DeclLoc The location of the declaration itself.
2618 /// \param SS the scope specifier that will be matched to the given template
2619 /// parameter lists. This scope specifier precedes a qualified name that is
2622 /// \param TemplateId The template-id following the scope specifier, if there
2623 /// is one. Used to check for a missing 'template<>'.
2625 /// \param ParamLists the template parameter lists, from the outermost to the
2626 /// innermost template parameter lists.
2628 /// \param IsFriend Whether to apply the slightly different rules for
2629 /// matching template parameters to scope specifiers in friend
2632 /// \param IsMemberSpecialization will be set true if the scope specifier
2633 /// denotes a fully-specialized type, and therefore this is a declaration of
2634 /// a member specialization.
2636 /// \returns the template parameter list, if any, that corresponds to the
2637 /// name that is preceded by the scope specifier @p SS. This template
2638 /// parameter list may have template parameters (if we're declaring a
2639 /// template) or may have no template parameters (if we're declaring a
2640 /// template specialization), or may be NULL (if what we're declaring isn't
2641 /// itself a template).
2642 TemplateParameterList *Sema::MatchTemplateParametersToScopeSpecifier(
2643 SourceLocation DeclStartLoc, SourceLocation DeclLoc, const CXXScopeSpec &SS,
2644 TemplateIdAnnotation *TemplateId,
2645 ArrayRef<TemplateParameterList *> ParamLists, bool IsFriend,
2646 bool &IsMemberSpecialization, bool &Invalid) {
2647 IsMemberSpecialization = false;
2650 // The sequence of nested types to which we will match up the template
2651 // parameter lists. We first build this list by starting with the type named
2652 // by the nested-name-specifier and walking out until we run out of types.
2653 SmallVector<QualType, 4> NestedTypes;
2655 if (SS.getScopeRep()) {
2656 if (CXXRecordDecl *Record
2657 = dyn_cast_or_null<CXXRecordDecl>(computeDeclContext(SS, true)))
2658 T = Context.getTypeDeclType(Record);
2660 T = QualType(SS.getScopeRep()->getAsType(), 0);
2663 // If we found an explicit specialization that prevents us from needing
2664 // 'template<>' headers, this will be set to the location of that
2665 // explicit specialization.
2666 SourceLocation ExplicitSpecLoc;
2668 while (!T.isNull()) {
2669 NestedTypes.push_back(T);
2671 // Retrieve the parent of a record type.
2672 if (CXXRecordDecl *Record = T->getAsCXXRecordDecl()) {
2673 // If this type is an explicit specialization, we're done.
2674 if (ClassTemplateSpecializationDecl *Spec
2675 = dyn_cast<ClassTemplateSpecializationDecl>(Record)) {
2676 if (!isa<ClassTemplatePartialSpecializationDecl>(Spec) &&
2677 Spec->getSpecializationKind() == TSK_ExplicitSpecialization) {
2678 ExplicitSpecLoc = Spec->getLocation();
2681 } else if (Record->getTemplateSpecializationKind()
2682 == TSK_ExplicitSpecialization) {
2683 ExplicitSpecLoc = Record->getLocation();
2687 if (TypeDecl *Parent = dyn_cast<TypeDecl>(Record->getParent()))
2688 T = Context.getTypeDeclType(Parent);
2694 if (const TemplateSpecializationType *TST
2695 = T->getAs<TemplateSpecializationType>()) {
2696 if (TemplateDecl *Template = TST->getTemplateName().getAsTemplateDecl()) {
2697 if (TypeDecl *Parent = dyn_cast<TypeDecl>(Template->getDeclContext()))
2698 T = Context.getTypeDeclType(Parent);
2705 // Look one step prior in a dependent template specialization type.
2706 if (const DependentTemplateSpecializationType *DependentTST
2707 = T->getAs<DependentTemplateSpecializationType>()) {
2708 if (NestedNameSpecifier *NNS = DependentTST->getQualifier())
2709 T = QualType(NNS->getAsType(), 0);
2715 // Look one step prior in a dependent name type.
2716 if (const DependentNameType *DependentName = T->getAs<DependentNameType>()){
2717 if (NestedNameSpecifier *NNS = DependentName->getQualifier())
2718 T = QualType(NNS->getAsType(), 0);
2724 // Retrieve the parent of an enumeration type.
2725 if (const EnumType *EnumT = T->getAs<EnumType>()) {
2726 // FIXME: Forward-declared enums require a TSK_ExplicitSpecialization
2728 EnumDecl *Enum = EnumT->getDecl();
2730 // Get to the parent type.
2731 if (TypeDecl *Parent = dyn_cast<TypeDecl>(Enum->getParent()))
2732 T = Context.getTypeDeclType(Parent);
2740 // Reverse the nested types list, since we want to traverse from the outermost
2741 // to the innermost while checking template-parameter-lists.
2742 std::reverse(NestedTypes.begin(), NestedTypes.end());
2744 // C++0x [temp.expl.spec]p17:
2745 // A member or a member template may be nested within many
2746 // enclosing class templates. In an explicit specialization for
2747 // such a member, the member declaration shall be preceded by a
2748 // template<> for each enclosing class template that is
2749 // explicitly specialized.
2750 bool SawNonEmptyTemplateParameterList = false;
2752 auto CheckExplicitSpecialization = [&](SourceRange Range, bool Recovery) {
2753 if (SawNonEmptyTemplateParameterList) {
2754 Diag(DeclLoc, diag::err_specialize_member_of_template)
2755 << !Recovery << Range;
2757 IsMemberSpecialization = false;
2764 auto DiagnoseMissingExplicitSpecialization = [&] (SourceRange Range) {
2765 // Check that we can have an explicit specialization here.
2766 if (CheckExplicitSpecialization(Range, true))
2769 // We don't have a template header, but we should.
2770 SourceLocation ExpectedTemplateLoc;
2771 if (!ParamLists.empty())
2772 ExpectedTemplateLoc = ParamLists[0]->getTemplateLoc();
2774 ExpectedTemplateLoc = DeclStartLoc;
2776 Diag(DeclLoc, diag::err_template_spec_needs_header)
2778 << FixItHint::CreateInsertion(ExpectedTemplateLoc, "template<> ");
2782 unsigned ParamIdx = 0;
2783 for (unsigned TypeIdx = 0, NumTypes = NestedTypes.size(); TypeIdx != NumTypes;
2785 T = NestedTypes[TypeIdx];
2787 // Whether we expect a 'template<>' header.
2788 bool NeedEmptyTemplateHeader = false;
2790 // Whether we expect a template header with parameters.
2791 bool NeedNonemptyTemplateHeader = false;
2793 // For a dependent type, the set of template parameters that we
2795 TemplateParameterList *ExpectedTemplateParams = nullptr;
2797 // C++0x [temp.expl.spec]p15:
2798 // A member or a member template may be nested within many enclosing
2799 // class templates. In an explicit specialization for such a member, the
2800 // member declaration shall be preceded by a template<> for each
2801 // enclosing class template that is explicitly specialized.
2802 if (CXXRecordDecl *Record = T->getAsCXXRecordDecl()) {
2803 if (ClassTemplatePartialSpecializationDecl *Partial
2804 = dyn_cast<ClassTemplatePartialSpecializationDecl>(Record)) {
2805 ExpectedTemplateParams = Partial->getTemplateParameters();
2806 NeedNonemptyTemplateHeader = true;
2807 } else if (Record->isDependentType()) {
2808 if (Record->getDescribedClassTemplate()) {
2809 ExpectedTemplateParams = Record->getDescribedClassTemplate()
2810 ->getTemplateParameters();
2811 NeedNonemptyTemplateHeader = true;
2813 } else if (ClassTemplateSpecializationDecl *Spec
2814 = dyn_cast<ClassTemplateSpecializationDecl>(Record)) {
2815 // C++0x [temp.expl.spec]p4:
2816 // Members of an explicitly specialized class template are defined
2817 // in the same manner as members of normal classes, and not using
2818 // the template<> syntax.
2819 if (Spec->getSpecializationKind() != TSK_ExplicitSpecialization)
2820 NeedEmptyTemplateHeader = true;
2823 } else if (Record->getTemplateSpecializationKind()) {
2824 if (Record->getTemplateSpecializationKind()
2825 != TSK_ExplicitSpecialization &&
2826 TypeIdx == NumTypes - 1)
2827 IsMemberSpecialization = true;
2831 } else if (const TemplateSpecializationType *TST
2832 = T->getAs<TemplateSpecializationType>()) {
2833 if (TemplateDecl *Template = TST->getTemplateName().getAsTemplateDecl()) {
2834 ExpectedTemplateParams = Template->getTemplateParameters();
2835 NeedNonemptyTemplateHeader = true;
2837 } else if (T->getAs<DependentTemplateSpecializationType>()) {
2838 // FIXME: We actually could/should check the template arguments here
2839 // against the corresponding template parameter list.
2840 NeedNonemptyTemplateHeader = false;
2843 // C++ [temp.expl.spec]p16:
2844 // In an explicit specialization declaration for a member of a class
2845 // template or a member template that ap- pears in namespace scope, the
2846 // member template and some of its enclosing class templates may remain
2847 // unspecialized, except that the declaration shall not explicitly
2848 // specialize a class member template if its en- closing class templates
2849 // are not explicitly specialized as well.
2850 if (ParamIdx < ParamLists.size()) {
2851 if (ParamLists[ParamIdx]->size() == 0) {
2852 if (CheckExplicitSpecialization(ParamLists[ParamIdx]->getSourceRange(),
2856 SawNonEmptyTemplateParameterList = true;
2859 if (NeedEmptyTemplateHeader) {
2860 // If we're on the last of the types, and we need a 'template<>' header
2861 // here, then it's a member specialization.
2862 if (TypeIdx == NumTypes - 1)
2863 IsMemberSpecialization = true;
2865 if (ParamIdx < ParamLists.size()) {
2866 if (ParamLists[ParamIdx]->size() > 0) {
2867 // The header has template parameters when it shouldn't. Complain.
2868 Diag(ParamLists[ParamIdx]->getTemplateLoc(),
2869 diag::err_template_param_list_matches_nontemplate)
2871 << SourceRange(ParamLists[ParamIdx]->getLAngleLoc(),
2872 ParamLists[ParamIdx]->getRAngleLoc())
2873 << getRangeOfTypeInNestedNameSpecifier(Context, T, SS);
2878 // Consume this template header.
2884 if (DiagnoseMissingExplicitSpecialization(
2885 getRangeOfTypeInNestedNameSpecifier(Context, T, SS)))
2891 if (NeedNonemptyTemplateHeader) {
2892 // In friend declarations we can have template-ids which don't
2893 // depend on the corresponding template parameter lists. But
2894 // assume that empty parameter lists are supposed to match this
2896 if (IsFriend && T->isDependentType()) {
2897 if (ParamIdx < ParamLists.size() &&
2898 DependsOnTemplateParameters(T, ParamLists[ParamIdx]))
2899 ExpectedTemplateParams = nullptr;
2904 if (ParamIdx < ParamLists.size()) {
2905 // Check the template parameter list, if we can.
2906 if (ExpectedTemplateParams &&
2907 !TemplateParameterListsAreEqual(ParamLists[ParamIdx],
2908 ExpectedTemplateParams,
2909 true, TPL_TemplateMatch))
2913 CheckTemplateParameterList(ParamLists[ParamIdx], nullptr,
2914 TPC_ClassTemplateMember))
2921 Diag(DeclLoc, diag::err_template_spec_needs_template_parameters)
2923 << getRangeOfTypeInNestedNameSpecifier(Context, T, SS);
2929 // If there were at least as many template-ids as there were template
2930 // parameter lists, then there are no template parameter lists remaining for
2931 // the declaration itself.
2932 if (ParamIdx >= ParamLists.size()) {
2933 if (TemplateId && !IsFriend) {
2934 // We don't have a template header for the declaration itself, but we
2936 DiagnoseMissingExplicitSpecialization(SourceRange(TemplateId->LAngleLoc,
2937 TemplateId->RAngleLoc));
2939 // Fabricate an empty template parameter list for the invented header.
2940 return TemplateParameterList::Create(Context, SourceLocation(),
2941 SourceLocation(), None,
2942 SourceLocation(), nullptr);
2948 // If there were too many template parameter lists, complain about that now.
2949 if (ParamIdx < ParamLists.size() - 1) {
2950 bool HasAnyExplicitSpecHeader = false;
2951 bool AllExplicitSpecHeaders = true;
2952 for (unsigned I = ParamIdx, E = ParamLists.size() - 1; I != E; ++I) {
2953 if (ParamLists[I]->size() == 0)
2954 HasAnyExplicitSpecHeader = true;
2956 AllExplicitSpecHeaders = false;
2959 Diag(ParamLists[ParamIdx]->getTemplateLoc(),
2960 AllExplicitSpecHeaders ? diag::warn_template_spec_extra_headers
2961 : diag::err_template_spec_extra_headers)
2962 << SourceRange(ParamLists[ParamIdx]->getTemplateLoc(),
2963 ParamLists[ParamLists.size() - 2]->getRAngleLoc());
2965 // If there was a specialization somewhere, such that 'template<>' is
2966 // not required, and there were any 'template<>' headers, note where the
2967 // specialization occurred.
2968 if (ExplicitSpecLoc.isValid() && HasAnyExplicitSpecHeader)
2969 Diag(ExplicitSpecLoc,
2970 diag::note_explicit_template_spec_does_not_need_header)
2971 << NestedTypes.back();
2973 // We have a template parameter list with no corresponding scope, which
2974 // means that the resulting template declaration can't be instantiated
2975 // properly (we'll end up with dependent nodes when we shouldn't).
2976 if (!AllExplicitSpecHeaders)
2980 // C++ [temp.expl.spec]p16:
2981 // In an explicit specialization declaration for a member of a class
2982 // template or a member template that ap- pears in namespace scope, the
2983 // member template and some of its enclosing class templates may remain
2984 // unspecialized, except that the declaration shall not explicitly
2985 // specialize a class member template if its en- closing class templates
2986 // are not explicitly specialized as well.
2987 if (ParamLists.back()->size() == 0 &&
2988 CheckExplicitSpecialization(ParamLists[ParamIdx]->getSourceRange(),
2992 // Return the last template parameter list, which corresponds to the
2993 // entity being declared.
2994 return ParamLists.back();
2997 void Sema::NoteAllFoundTemplates(TemplateName Name) {
2998 if (TemplateDecl *Template = Name.getAsTemplateDecl()) {
2999 Diag(Template->getLocation(), diag::note_template_declared_here)
3000 << (isa<FunctionTemplateDecl>(Template)
3002 : isa<ClassTemplateDecl>(Template)
3004 : isa<VarTemplateDecl>(Template)
3006 : isa<TypeAliasTemplateDecl>(Template) ? 3 : 4)
3007 << Template->getDeclName();
3011 if (OverloadedTemplateStorage *OST = Name.getAsOverloadedTemplate()) {
3012 for (OverloadedTemplateStorage::iterator I = OST->begin(),
3015 Diag((*I)->getLocation(), diag::note_template_declared_here)
3016 << 0 << (*I)->getDeclName();
3023 checkBuiltinTemplateIdType(Sema &SemaRef, BuiltinTemplateDecl *BTD,
3024 const SmallVectorImpl<TemplateArgument> &Converted,
3025 SourceLocation TemplateLoc,
3026 TemplateArgumentListInfo &TemplateArgs) {
3027 ASTContext &Context = SemaRef.getASTContext();
3028 switch (BTD->getBuiltinTemplateKind()) {
3029 case BTK__make_integer_seq: {
3030 // Specializations of __make_integer_seq<S, T, N> are treated like
3031 // S<T, 0, ..., N-1>.
3033 // C++14 [inteseq.intseq]p1:
3034 // T shall be an integer type.
3035 if (!Converted[1].getAsType()->isIntegralType(Context)) {
3036 SemaRef.Diag(TemplateArgs[1].getLocation(),
3037 diag::err_integer_sequence_integral_element_type);
3041 // C++14 [inteseq.make]p1:
3042 // If N is negative the program is ill-formed.
3043 TemplateArgument NumArgsArg = Converted[2];
3044 llvm::APSInt NumArgs = NumArgsArg.getAsIntegral();
3046 SemaRef.Diag(TemplateArgs[2].getLocation(),
3047 diag::err_integer_sequence_negative_length);
3051 QualType ArgTy = NumArgsArg.getIntegralType();
3052 TemplateArgumentListInfo SyntheticTemplateArgs;
3053 // The type argument gets reused as the first template argument in the
3054 // synthetic template argument list.
3055 SyntheticTemplateArgs.addArgument(TemplateArgs[1]);
3056 // Expand N into 0 ... N-1.
3057 for (llvm::APSInt I(NumArgs.getBitWidth(), NumArgs.isUnsigned());
3059 TemplateArgument TA(Context, I, ArgTy);
3060 SyntheticTemplateArgs.addArgument(SemaRef.getTrivialTemplateArgumentLoc(
3061 TA, ArgTy, TemplateArgs[2].getLocation()));
3063 // The first template argument will be reused as the template decl that
3064 // our synthetic template arguments will be applied to.
3065 return SemaRef.CheckTemplateIdType(Converted[0].getAsTemplate(),
3066 TemplateLoc, SyntheticTemplateArgs);
3069 case BTK__type_pack_element:
3070 // Specializations of
3071 // __type_pack_element<Index, T_1, ..., T_N>
3072 // are treated like T_Index.
3073 assert(Converted.size() == 2 &&
3074 "__type_pack_element should be given an index and a parameter pack");
3076 // If the Index is out of bounds, the program is ill-formed.
3077 TemplateArgument IndexArg = Converted[0], Ts = Converted[1];
3078 llvm::APSInt Index = IndexArg.getAsIntegral();
3079 assert(Index >= 0 && "the index used with __type_pack_element should be of "
3080 "type std::size_t, and hence be non-negative");
3081 if (Index >= Ts.pack_size()) {
3082 SemaRef.Diag(TemplateArgs[0].getLocation(),
3083 diag::err_type_pack_element_out_of_bounds);
3087 // We simply return the type at index `Index`.
3088 auto Nth = std::next(Ts.pack_begin(), Index.getExtValue());
3089 return Nth->getAsType();
3091 llvm_unreachable("unexpected BuiltinTemplateDecl!");
3094 /// Determine whether this alias template is "enable_if_t".
3095 static bool isEnableIfAliasTemplate(TypeAliasTemplateDecl *AliasTemplate) {
3096 return AliasTemplate->getName().equals("enable_if_t");
3099 /// Collect all of the separable terms in the given condition, which
3100 /// might be a conjunction.
3102 /// FIXME: The right answer is to convert the logical expression into
3103 /// disjunctive normal form, so we can find the first failed term
3104 /// within each possible clause.
3105 static void collectConjunctionTerms(Expr *Clause,
3106 SmallVectorImpl<Expr *> &Terms) {
3107 if (auto BinOp = dyn_cast<BinaryOperator>(Clause->IgnoreParenImpCasts())) {
3108 if (BinOp->getOpcode() == BO_LAnd) {
3109 collectConjunctionTerms(BinOp->getLHS(), Terms);
3110 collectConjunctionTerms(BinOp->getRHS(), Terms);
3116 Terms.push_back(Clause);
3119 // The ranges-v3 library uses an odd pattern of a top-level "||" with
3120 // a left-hand side that is value-dependent but never true. Identify
3121 // the idiom and ignore that term.
3122 static Expr *lookThroughRangesV3Condition(Preprocessor &PP, Expr *Cond) {
3124 auto *BinOp = dyn_cast<BinaryOperator>(Cond->IgnoreParenImpCasts());
3125 if (!BinOp) return Cond;
3127 if (BinOp->getOpcode() != BO_LOr) return Cond;
3129 // With an inner '==' that has a literal on the right-hand side.
3130 Expr *LHS = BinOp->getLHS();
3131 auto *InnerBinOp = dyn_cast<BinaryOperator>(LHS->IgnoreParenImpCasts());
3132 if (!InnerBinOp) return Cond;
3134 if (InnerBinOp->getOpcode() != BO_EQ ||
3135 !isa<IntegerLiteral>(InnerBinOp->getRHS()))
3138 // If the inner binary operation came from a macro expansion named
3139 // CONCEPT_REQUIRES or CONCEPT_REQUIRES_, return the right-hand side
3140 // of the '||', which is the real, user-provided condition.
3141 SourceLocation Loc = InnerBinOp->getExprLoc();
3142 if (!Loc.isMacroID()) return Cond;
3144 StringRef MacroName = PP.getImmediateMacroName(Loc);
3145 if (MacroName == "CONCEPT_REQUIRES" || MacroName == "CONCEPT_REQUIRES_")
3146 return BinOp->getRHS();
3153 // A PrinterHelper that prints more helpful diagnostics for some sub-expressions
3154 // within failing boolean expression, such as substituting template parameters
3155 // for actual types.
3156 class FailedBooleanConditionPrinterHelper : public PrinterHelper {
3158 explicit FailedBooleanConditionPrinterHelper(const PrintingPolicy &P)
3161 bool handledStmt(Stmt *E, raw_ostream &OS) override {
3162 const auto *DR = dyn_cast<DeclRefExpr>(E);
3163 if (DR && DR->getQualifier()) {
3164 // If this is a qualified name, expand the template arguments in nested
3166 DR->getQualifier()->print(OS, Policy, true);
3167 // Then print the decl itself.
3168 const ValueDecl *VD = DR->getDecl();
3169 OS << VD->getName();
3170 if (const auto *IV = dyn_cast<VarTemplateSpecializationDecl>(VD)) {
3171 // This is a template variable, print the expanded template arguments.
3172 printTemplateArgumentList(OS, IV->getTemplateArgs().asArray(), Policy);
3180 const PrintingPolicy Policy;
3183 } // end anonymous namespace
3185 std::pair<Expr *, std::string>
3186 Sema::findFailedBooleanCondition(Expr *Cond) {
3187 Cond = lookThroughRangesV3Condition(PP, Cond);
3189 // Separate out all of the terms in a conjunction.
3190 SmallVector<Expr *, 4> Terms;
3191 collectConjunctionTerms(Cond, Terms);
3193 // Determine which term failed.
3194 Expr *FailedCond = nullptr;
3195 for (Expr *Term : Terms) {
3196 Expr *TermAsWritten = Term->IgnoreParenImpCasts();
3198 // Literals are uninteresting.
3199 if (isa<CXXBoolLiteralExpr>(TermAsWritten) ||
3200 isa<IntegerLiteral>(TermAsWritten))
3203 // The initialization of the parameter from the argument is
3204 // a constant-evaluated context.
3205 EnterExpressionEvaluationContext ConstantEvaluated(
3206 *this, Sema::ExpressionEvaluationContext::ConstantEvaluated);
3209 if (Term->EvaluateAsBooleanCondition(Succeeded, Context) &&
3211 FailedCond = TermAsWritten;
3216 FailedCond = Cond->IgnoreParenImpCasts();
3218 std::string Description;
3220 llvm::raw_string_ostream Out(Description);
3221 PrintingPolicy Policy = getPrintingPolicy();
3222 Policy.PrintCanonicalTypes = true;
3223 FailedBooleanConditionPrinterHelper Helper(Policy);
3224 FailedCond->printPretty(Out, &Helper, Policy, 0, "\n", nullptr);
3226 return { FailedCond, Description };
3229 QualType Sema::CheckTemplateIdType(TemplateName Name,
3230 SourceLocation TemplateLoc,
3231 TemplateArgumentListInfo &TemplateArgs) {
3232 DependentTemplateName *DTN
3233 = Name.getUnderlying().getAsDependentTemplateName();
3234 if (DTN && DTN->isIdentifier())
3235 // When building a template-id where the template-name is dependent,
3236 // assume the template is a type template. Either our assumption is
3237 // correct, or the code is ill-formed and will be diagnosed when the
3238 // dependent name is substituted.
3239 return Context.getDependentTemplateSpecializationType(ETK_None,
3240 DTN->getQualifier(),
3241 DTN->getIdentifier(),
3244 TemplateDecl *Template = Name.getAsTemplateDecl();
3245 if (!Template || isa<FunctionTemplateDecl>(Template) ||
3246 isa<VarTemplateDecl>(Template) ||
3247 isa<ConceptDecl>(Template)) {
3248 // We might have a substituted template template parameter pack. If so,
3249 // build a template specialization type for it.
3250 if (Name.getAsSubstTemplateTemplateParmPack())
3251 return Context.getTemplateSpecializationType(Name, TemplateArgs);
3253 Diag(TemplateLoc, diag::err_template_id_not_a_type)
3255 NoteAllFoundTemplates(Name);
3259 // Check that the template argument list is well-formed for this
3261 SmallVector<TemplateArgument, 4> Converted;
3262 if (CheckTemplateArgumentList(Template, TemplateLoc, TemplateArgs,
3268 bool InstantiationDependent = false;
3269 if (TypeAliasTemplateDecl *AliasTemplate =
3270 dyn_cast<TypeAliasTemplateDecl>(Template)) {
3271 // Find the canonical type for this type alias template specialization.
3272 TypeAliasDecl *Pattern = AliasTemplate->getTemplatedDecl();
3273 if (Pattern->isInvalidDecl())
3276 TemplateArgumentList StackTemplateArgs(TemplateArgumentList::OnStack,
3279 // Only substitute for the innermost template argument list.
3280 MultiLevelTemplateArgumentList TemplateArgLists;
3281 TemplateArgLists.addOuterTemplateArguments(&StackTemplateArgs);
3282 unsigned Depth = AliasTemplate->getTemplateParameters()->getDepth();
3283 for (unsigned I = 0; I < Depth; ++I)
3284 TemplateArgLists.addOuterTemplateArguments(None);
3286 LocalInstantiationScope Scope(*this);
3287 InstantiatingTemplate Inst(*this, TemplateLoc, Template);
3288 if (Inst.isInvalid())
3291 CanonType = SubstType(Pattern->getUnderlyingType(),
3292 TemplateArgLists, AliasTemplate->getLocation(),
3293 AliasTemplate->getDeclName());
3294 if (CanonType.isNull()) {
3295 // If this was enable_if and we failed to find the nested type
3296 // within enable_if in a SFINAE context, dig out the specific
3297 // enable_if condition that failed and present that instead.
3298 if (isEnableIfAliasTemplate(AliasTemplate)) {
3299 if (auto DeductionInfo = isSFINAEContext()) {
3300 if (*DeductionInfo &&
3301 (*DeductionInfo)->hasSFINAEDiagnostic() &&
3302 (*DeductionInfo)->peekSFINAEDiagnostic().second.getDiagID() ==
3303 diag::err_typename_nested_not_found_enable_if &&
3304 TemplateArgs[0].getArgument().getKind()
3305 == TemplateArgument::Expression) {
3307 std::string FailedDescription;
3308 std::tie(FailedCond, FailedDescription) =
3309 findFailedBooleanCondition(TemplateArgs[0].getSourceExpression());
3311 // Remove the old SFINAE diagnostic.
3312 PartialDiagnosticAt OldDiag =
3313 {SourceLocation(), PartialDiagnostic::NullDiagnostic()};
3314 (*DeductionInfo)->takeSFINAEDiagnostic(OldDiag);
3316 // Add a new SFINAE diagnostic specifying which condition
3318 (*DeductionInfo)->addSFINAEDiagnostic(
3320 PDiag(diag::err_typename_nested_not_found_requirement)
3321 << FailedDescription
3322 << FailedCond->getSourceRange());
3329 } else if (Name.isDependent() ||
3330 TemplateSpecializationType::anyDependentTemplateArguments(
3331 TemplateArgs, InstantiationDependent)) {
3332 // This class template specialization is a dependent
3333 // type. Therefore, its canonical type is another class template
3334 // specialization type that contains all of the converted
3335 // arguments in canonical form. This ensures that, e.g., A<T> and
3336 // A<T, T> have identical types when A is declared as:
3338 // template<typename T, typename U = T> struct A;
3339 CanonType = Context.getCanonicalTemplateSpecializationType(Name, Converted);
3341 // This might work out to be a current instantiation, in which
3342 // case the canonical type needs to be the InjectedClassNameType.
3344 // TODO: in theory this could be a simple hashtable lookup; most
3345 // changes to CurContext don't change the set of current
3347 if (isa<ClassTemplateDecl>(Template)) {
3348 for (DeclContext *Ctx = CurContext; Ctx; Ctx = Ctx->getLookupParent()) {
3349 // If we get out to a namespace, we're done.
3350 if (Ctx->isFileContext()) break;
3352 // If this isn't a record, keep looking.
3353 CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(Ctx);
3354 if (!Record) continue;
3356 // Look for one of the two cases with InjectedClassNameTypes
3357 // and check whether it's the same template.
3358 if (!isa<ClassTemplatePartialSpecializationDecl>(Record) &&
3359 !Record->getDescribedClassTemplate())
3362 // Fetch the injected class name type and check whether its
3363 // injected type is equal to the type we just built.
3364 QualType ICNT = Context.getTypeDeclType(Record);
3365 QualType Injected = cast<InjectedClassNameType>(ICNT)
3366 ->getInjectedSpecializationType();
3368 if (CanonType != Injected->getCanonicalTypeInternal())
3371 // If so, the canonical type of this TST is the injected
3372 // class name type of the record we just found.
3373 assert(ICNT.isCanonical());
3378 } else if (ClassTemplateDecl *ClassTemplate
3379 = dyn_cast<ClassTemplateDecl>(Template)) {
3380 // Find the class template specialization declaration that
3381 // corresponds to these arguments.
3382 void *InsertPos = nullptr;
3383 ClassTemplateSpecializationDecl *Decl
3384 = ClassTemplate->findSpecialization(Converted, InsertPos);
3386 // This is the first time we have referenced this class template
3387 // specialization. Create the canonical declaration and add it to
3388 // the set of specializations.
3389 Decl = ClassTemplateSpecializationDecl::Create(
3390 Context, ClassTemplate->getTemplatedDecl()->getTagKind(),
3391 ClassTemplate->getDeclContext(),
3392 ClassTemplate->getTemplatedDecl()->getBeginLoc(),
3393 ClassTemplate->getLocation(), ClassTemplate, Converted, nullptr);
3394 ClassTemplate->AddSpecialization(Decl, InsertPos);
3395 if (ClassTemplate->isOutOfLine())
3396 Decl->setLexicalDeclContext(ClassTemplate->getLexicalDeclContext());
3399 if (Decl->getSpecializationKind() == TSK_Undeclared) {
3400 MultiLevelTemplateArgumentList TemplateArgLists;
3401 TemplateArgLists.addOuterTemplateArguments(Converted);
3402 InstantiateAttrsForDecl(TemplateArgLists, ClassTemplate->getTemplatedDecl(),
3406 // Diagnose uses of this specialization.
3407 (void)DiagnoseUseOfDecl(Decl, TemplateLoc);
3409 CanonType = Context.getTypeDeclType(Decl);
3410 assert(isa<RecordType>(CanonType) &&
3411 "type of non-dependent specialization is not a RecordType");
3412 } else if (auto *BTD = dyn_cast<BuiltinTemplateDecl>(Template)) {
3413 CanonType = checkBuiltinTemplateIdType(*this, BTD, Converted, TemplateLoc,
3417 // Build the fully-sugared type for this class template
3418 // specialization, which refers back to the class template
3419 // specialization we created or found.
3420 return Context.getTemplateSpecializationType(Name, TemplateArgs, CanonType);
3423 void Sema::ActOnUndeclaredTypeTemplateName(Scope *S, TemplateTy &ParsedName,
3424 TemplateNameKind &TNK,
3425 SourceLocation NameLoc,
3426 IdentifierInfo *&II) {
3427 assert(TNK == TNK_Undeclared_template && "not an undeclared template name");
3429 TemplateName Name = ParsedName.get();
3430 auto *ATN = Name.getAsAssumedTemplateName();
3431 assert(ATN && "not an assumed template name");
3432 II = ATN->getDeclName().getAsIdentifierInfo();
3434 if (!resolveAssumedTemplateNameAsType(S, Name, NameLoc, /*Diagnose*/false)) {
3435 // Resolved to a type template name.
3436 ParsedName = TemplateTy::make(Name);
3437 TNK = TNK_Type_template;
3441 bool Sema::resolveAssumedTemplateNameAsType(Scope *S, TemplateName &Name,
3442 SourceLocation NameLoc,
3444 // We assumed this undeclared identifier to be an (ADL-only) function
3445 // template name, but it was used in a context where a type was required.
3446 // Try to typo-correct it now.
3447 AssumedTemplateStorage *ATN = Name.getAsAssumedTemplateName();
3448 assert(ATN && "not an assumed template name");
3450 LookupResult R(*this, ATN->getDeclName(), NameLoc, LookupOrdinaryName);
3451 struct CandidateCallback : CorrectionCandidateCallback {
3452 bool ValidateCandidate(const TypoCorrection &TC) override {
3453 return TC.getCorrectionDecl() &&
3454 getAsTypeTemplateDecl(TC.getCorrectionDecl());
3456 std::unique_ptr<CorrectionCandidateCallback> clone() override {
3457 return llvm::make_unique<CandidateCallback>(*this);
3461 TypoCorrection Corrected =
3462 CorrectTypo(R.getLookupNameInfo(), R.getLookupKind(), S, nullptr,
3463 FilterCCC, CTK_ErrorRecovery);
3464 if (Corrected && Corrected.getFoundDecl()) {
3465 diagnoseTypo(Corrected, PDiag(diag::err_no_template_suggest)
3466 << ATN->getDeclName());
3467 Name = TemplateName(Corrected.getCorrectionDeclAs<TemplateDecl>());
3472 Diag(R.getNameLoc(), diag::err_no_template) << R.getLookupName();
3476 TypeResult Sema::ActOnTemplateIdType(
3477 Scope *S, CXXScopeSpec &SS, SourceLocation TemplateKWLoc,
3478 TemplateTy TemplateD, IdentifierInfo *TemplateII,
3479 SourceLocation TemplateIILoc, SourceLocation LAngleLoc,
3480 ASTTemplateArgsPtr TemplateArgsIn, SourceLocation RAngleLoc,
3481 bool IsCtorOrDtorName, bool IsClassName) {
3485 if (!IsCtorOrDtorName && !IsClassName && SS.isSet()) {
3486 DeclContext *LookupCtx = computeDeclContext(SS, /*EnteringContext*/false);
3488 // C++ [temp.res]p3:
3489 // A qualified-id that refers to a type and in which the
3490 // nested-name-specifier depends on a template-parameter (14.6.2)
3491 // shall be prefixed by the keyword typename to indicate that the
3492 // qualified-id denotes a type, forming an
3493 // elaborated-type-specifier (7.1.5.3).
3494 if (!LookupCtx && isDependentScopeSpecifier(SS)) {
3495 Diag(SS.getBeginLoc(), diag::err_typename_missing_template)
3496 << SS.getScopeRep() << TemplateII->getName();
3497 // Recover as if 'typename' were specified.
3498 // FIXME: This is not quite correct recovery as we don't transform SS
3499 // into the corresponding dependent form (and we don't diagnose missing
3500 // 'template' keywords within SS as a result).
3501 return ActOnTypenameType(nullptr, SourceLocation(), SS, TemplateKWLoc,
3502 TemplateD, TemplateII, TemplateIILoc, LAngleLoc,
3503 TemplateArgsIn, RAngleLoc);
3506 // Per C++ [class.qual]p2, if the template-id was an injected-class-name,
3507 // it's not actually allowed to be used as a type in most cases. Because
3508 // we annotate it before we know whether it's valid, we have to check for
3510 auto *LookupRD = dyn_cast_or_null<CXXRecordDecl>(LookupCtx);
3511 if (LookupRD && LookupRD->getIdentifier() == TemplateII) {
3513 TemplateKWLoc.isInvalid()
3514 ? diag::err_out_of_line_qualified_id_type_names_constructor
3515 : diag::ext_out_of_line_qualified_id_type_names_constructor)
3516 << TemplateII << 0 /*injected-class-name used as template name*/
3517 << 1 /*if any keyword was present, it was 'template'*/;
3521 TemplateName Template = TemplateD.get();
3522 if (Template.getAsAssumedTemplateName() &&
3523 resolveAssumedTemplateNameAsType(S, Template, TemplateIILoc))
3526 // Translate the parser's template argument list in our AST format.
3527 TemplateArgumentListInfo TemplateArgs(LAngleLoc, RAngleLoc);
3528 translateTemplateArguments(TemplateArgsIn, TemplateArgs);
3530 if (DependentTemplateName *DTN = Template.getAsDependentTemplateName()) {
3532 = Context.getDependentTemplateSpecializationType(ETK_None,
3533 DTN->getQualifier(),
3534 DTN->getIdentifier(),
3536 // Build type-source information.
3538 DependentTemplateSpecializationTypeLoc SpecTL
3539 = TLB.push<DependentTemplateSpecializationTypeLoc>(T);
3540 SpecTL.setElaboratedKeywordLoc(SourceLocation());
3541 SpecTL.setQualifierLoc(SS.getWithLocInContext(Context));
3542 SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
3543 SpecTL.setTemplateNameLoc(TemplateIILoc);
3544 SpecTL.setLAngleLoc(LAngleLoc);
3545 SpecTL.setRAngleLoc(RAngleLoc);
3546 for (unsigned I = 0, N = SpecTL.getNumArgs(); I != N; ++I)
3547 SpecTL.setArgLocInfo(I, TemplateArgs[I].getLocInfo());
3548 return CreateParsedType(T, TLB.getTypeSourceInfo(Context, T));
3551 QualType Result = CheckTemplateIdType(Template, TemplateIILoc, TemplateArgs);
3552 if (Result.isNull())
3555 // Build type-source information.
3557 TemplateSpecializationTypeLoc SpecTL
3558 = TLB.push<TemplateSpecializationTypeLoc>(Result);
3559 SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
3560 SpecTL.setTemplateNameLoc(TemplateIILoc);
3561 SpecTL.setLAngleLoc(LAngleLoc);
3562 SpecTL.setRAngleLoc(RAngleLoc);
3563 for (unsigned i = 0, e = SpecTL.getNumArgs(); i != e; ++i)
3564 SpecTL.setArgLocInfo(i, TemplateArgs[i].getLocInfo());
3566 // NOTE: avoid constructing an ElaboratedTypeLoc if this is a
3567 // constructor or destructor name (in such a case, the scope specifier
3568 // will be attached to the enclosing Decl or Expr node).
3569 if (SS.isNotEmpty() && !IsCtorOrDtorName) {
3570 // Create an elaborated-type-specifier containing the nested-name-specifier.
3571 Result = Context.getElaboratedType(ETK_None, SS.getScopeRep(), Result);
3572 ElaboratedTypeLoc ElabTL = TLB.push<ElaboratedTypeLoc>(Result);
3573 ElabTL.setElaboratedKeywordLoc(SourceLocation());
3574 ElabTL.setQualifierLoc(SS.getWithLocInContext(Context));
3577 return CreateParsedType(Result, TLB.getTypeSourceInfo(Context, Result));
3580 TypeResult Sema::ActOnTagTemplateIdType(TagUseKind TUK,
3581 TypeSpecifierType TagSpec,
3582 SourceLocation TagLoc,
3584 SourceLocation TemplateKWLoc,
3585 TemplateTy TemplateD,
3586 SourceLocation TemplateLoc,
3587 SourceLocation LAngleLoc,
3588 ASTTemplateArgsPtr TemplateArgsIn,
3589 SourceLocation RAngleLoc) {
3590 TemplateName Template = TemplateD.get();
3592 // Translate the parser's template argument list in our AST format.
3593 TemplateArgumentListInfo TemplateArgs(LAngleLoc, RAngleLoc);
3594 translateTemplateArguments(TemplateArgsIn, TemplateArgs);
3596 // Determine the tag kind
3597 TagTypeKind TagKind = TypeWithKeyword::getTagTypeKindForTypeSpec(TagSpec);
3598 ElaboratedTypeKeyword Keyword
3599 = TypeWithKeyword::getKeywordForTagTypeKind(TagKind);
3601 if (DependentTemplateName *DTN = Template.getAsDependentTemplateName()) {
3602 QualType T = Context.getDependentTemplateSpecializationType(Keyword,
3603 DTN->getQualifier(),
3604 DTN->getIdentifier(),
3607 // Build type-source information.
3609 DependentTemplateSpecializationTypeLoc SpecTL
3610 = TLB.push<DependentTemplateSpecializationTypeLoc>(T);
3611 SpecTL.setElaboratedKeywordLoc(TagLoc);
3612 SpecTL.setQualifierLoc(SS.getWithLocInContext(Context));
3613 SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
3614 SpecTL.setTemplateNameLoc(TemplateLoc);
3615 SpecTL.setLAngleLoc(LAngleLoc);
3616 SpecTL.setRAngleLoc(RAngleLoc);
3617 for (unsigned I = 0, N = SpecTL.getNumArgs(); I != N; ++I)
3618 SpecTL.setArgLocInfo(I, TemplateArgs[I].getLocInfo());
3619 return CreateParsedType(T, TLB.getTypeSourceInfo(Context, T));
3622 if (TypeAliasTemplateDecl *TAT =
3623 dyn_cast_or_null<TypeAliasTemplateDecl>(Template.getAsTemplateDecl())) {
3624 // C++0x [dcl.type.elab]p2:
3625 // If the identifier resolves to a typedef-name or the simple-template-id
3626 // resolves to an alias template specialization, the
3627 // elaborated-type-specifier is ill-formed.
3628 Diag(TemplateLoc, diag::err_tag_reference_non_tag)
3629 << TAT << NTK_TypeAliasTemplate << TagKind;
3630 Diag(TAT->getLocation(), diag::note_declared_at);
3633 QualType Result = CheckTemplateIdType(Template, TemplateLoc, TemplateArgs);
3634 if (Result.isNull())
3635 return TypeResult(true);
3637 // Check the tag kind
3638 if (const RecordType *RT = Result->getAs<RecordType>()) {
3639 RecordDecl *D = RT->getDecl();
3641 IdentifierInfo *Id = D->getIdentifier();
3642 assert(Id && "templated class must have an identifier");
3644 if (!isAcceptableTagRedeclaration(D, TagKind, TUK == TUK_Definition,
3646 Diag(TagLoc, diag::err_use_with_wrong_tag)
3648 << FixItHint::CreateReplacement(SourceRange(TagLoc), D->getKindName());
3649 Diag(D->getLocation(), diag::note_previous_use);
3653 // Provide source-location information for the template specialization.
3655 TemplateSpecializationTypeLoc SpecTL
3656 = TLB.push<TemplateSpecializationTypeLoc>(Result);
3657 SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
3658 SpecTL.setTemplateNameLoc(TemplateLoc);
3659 SpecTL.setLAngleLoc(LAngleLoc);
3660 SpecTL.setRAngleLoc(RAngleLoc);
3661 for (unsigned i = 0, e = SpecTL.getNumArgs(); i != e; ++i)
3662 SpecTL.setArgLocInfo(i, TemplateArgs[i].getLocInfo());
3664 // Construct an elaborated type containing the nested-name-specifier (if any)
3666 Result = Context.getElaboratedType(Keyword, SS.getScopeRep(), Result);
3667 ElaboratedTypeLoc ElabTL = TLB.push<ElaboratedTypeLoc>(Result);
3668 ElabTL.setElaboratedKeywordLoc(TagLoc);
3669 ElabTL.setQualifierLoc(SS.getWithLocInContext(Context));
3670 return CreateParsedType(Result, TLB.getTypeSourceInfo(Context, Result));
3673 static bool CheckTemplateSpecializationScope(Sema &S, NamedDecl *Specialized,
3674 NamedDecl *PrevDecl,
3676 bool IsPartialSpecialization);
3678 static TemplateSpecializationKind getTemplateSpecializationKind(Decl *D);
3680 static bool isTemplateArgumentTemplateParameter(
3681 const TemplateArgument &Arg, unsigned Depth, unsigned Index) {
3682 switch (Arg.getKind()) {
3683 case TemplateArgument::Null:
3684 case TemplateArgument::NullPtr:
3685 case TemplateArgument::Integral:
3686 case TemplateArgument::Declaration:
3687 case TemplateArgument::Pack:
3688 case TemplateArgument::TemplateExpansion:
3691 case TemplateArgument::Type: {
3692 QualType Type = Arg.getAsType();
3693 const TemplateTypeParmType *TPT =
3694 Arg.getAsType()->getAs<TemplateTypeParmType>();
3695 return TPT && !Type.hasQualifiers() &&
3696 TPT->getDepth() == Depth && TPT->getIndex() == Index;
3699 case TemplateArgument::Expression: {
3700 DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Arg.getAsExpr());
3701 if (!DRE || !DRE->getDecl())
3703 const NonTypeTemplateParmDecl *NTTP =
3704 dyn_cast<NonTypeTemplateParmDecl>(DRE->getDecl());
3705 return NTTP && NTTP->getDepth() == Depth && NTTP->getIndex() == Index;
3708 case TemplateArgument::Template:
3709 const TemplateTemplateParmDecl *TTP =
3710 dyn_cast_or_null<TemplateTemplateParmDecl>(
3711 Arg.getAsTemplateOrTemplatePattern().getAsTemplateDecl());
3712 return TTP && TTP->getDepth() == Depth && TTP->getIndex() == Index;
3714 llvm_unreachable("unexpected kind of template argument");
3717 static bool isSameAsPrimaryTemplate(TemplateParameterList *Params,
3718 ArrayRef<TemplateArgument> Args) {
3719 if (Params->size() != Args.size())
3722 unsigned Depth = Params->getDepth();
3724 for (unsigned I = 0, N = Args.size(); I != N; ++I) {
3725 TemplateArgument Arg = Args[I];
3727 // If the parameter is a pack expansion, the argument must be a pack
3728 // whose only element is a pack expansion.
3729 if (Params->getParam(I)->isParameterPack()) {
3730 if (Arg.getKind() != TemplateArgument::Pack || Arg.pack_size() != 1 ||
3731 !Arg.pack_begin()->isPackExpansion())
3733 Arg = Arg.pack_begin()->getPackExpansionPattern();
3736 if (!isTemplateArgumentTemplateParameter(Arg, Depth, I))
3743 /// Convert the parser's template argument list representation into our form.
3744 static TemplateArgumentListInfo
3745 makeTemplateArgumentListInfo(Sema &S, TemplateIdAnnotation &TemplateId) {
3746 TemplateArgumentListInfo TemplateArgs(TemplateId.LAngleLoc,
3747 TemplateId.RAngleLoc);
3748 ASTTemplateArgsPtr TemplateArgsPtr(TemplateId.getTemplateArgs(),
3749 TemplateId.NumArgs);
3750 S.translateTemplateArguments(TemplateArgsPtr, TemplateArgs);
3751 return TemplateArgs;
3754 template<typename PartialSpecDecl>
3755 static void checkMoreSpecializedThanPrimary(Sema &S, PartialSpecDecl *Partial) {
3756 if (Partial->getDeclContext()->isDependentContext())
3759 // FIXME: Get the TDK from deduction in order to provide better diagnostics
3760 // for non-substitution-failure issues?
3761 TemplateDeductionInfo Info(Partial->getLocation());
3762 if (S.isMoreSpecializedThanPrimary(Partial, Info))
3765 auto *Template = Partial->getSpecializedTemplate();
3766 S.Diag(Partial->getLocation(),
3767 diag::ext_partial_spec_not_more_specialized_than_primary)
3768 << isa<VarTemplateDecl>(Template);
3770 if (Info.hasSFINAEDiagnostic()) {
3771 PartialDiagnosticAt Diag = {SourceLocation(),
3772 PartialDiagnostic::NullDiagnostic()};
3773 Info.takeSFINAEDiagnostic(Diag);
3774 SmallString<128> SFINAEArgString;
3775 Diag.second.EmitToString(S.getDiagnostics(), SFINAEArgString);
3777 diag::note_partial_spec_not_more_specialized_than_primary)
3781 S.Diag(Template->getLocation(), diag::note_template_decl_here);
3785 noteNonDeducibleParameters(Sema &S, TemplateParameterList *TemplateParams,
3786 const llvm::SmallBitVector &DeducibleParams) {
3787 for (unsigned I = 0, N = DeducibleParams.size(); I != N; ++I) {
3788 if (!DeducibleParams[I]) {
3789 NamedDecl *Param = TemplateParams->getParam(I);
3790 if (Param->getDeclName())
3791 S.Diag(Param->getLocation(), diag::note_non_deducible_parameter)
3792 << Param->getDeclName();
3794 S.Diag(Param->getLocation(), diag::note_non_deducible_parameter)
3801 template<typename PartialSpecDecl>
3802 static void checkTemplatePartialSpecialization(Sema &S,
3803 PartialSpecDecl *Partial) {
3804 // C++1z [temp.class.spec]p8: (DR1495)
3805 // - The specialization shall be more specialized than the primary
3806 // template (14.5.5.2).
3807 checkMoreSpecializedThanPrimary(S, Partial);
3809 // C++ [temp.class.spec]p8: (DR1315)
3810 // - Each template-parameter shall appear at least once in the
3811 // template-id outside a non-deduced context.
3812 // C++1z [temp.class.spec.match]p3 (P0127R2)
3813 // If the template arguments of a partial specialization cannot be
3814 // deduced because of the structure of its template-parameter-list
3815 // and the template-id, the program is ill-formed.
3816 auto *TemplateParams = Partial->getTemplateParameters();
3817 llvm::SmallBitVector DeducibleParams(TemplateParams->size());
3818 S.MarkUsedTemplateParameters(Partial->getTemplateArgs(), true,
3819 TemplateParams->getDepth(), DeducibleParams);
3821 if (!DeducibleParams.all()) {
3822 unsigned NumNonDeducible = DeducibleParams.size() - DeducibleParams.count();
3823 S.Diag(Partial->getLocation(), diag::ext_partial_specs_not_deducible)
3824 << isa<VarTemplatePartialSpecializationDecl>(Partial)
3825 << (NumNonDeducible > 1)
3826 << SourceRange(Partial->getLocation(),
3827 Partial->getTemplateArgsAsWritten()->RAngleLoc);
3828 noteNonDeducibleParameters(S, TemplateParams, DeducibleParams);
3832 void Sema::CheckTemplatePartialSpecialization(
3833 ClassTemplatePartialSpecializationDecl *Partial) {
3834 checkTemplatePartialSpecialization(*this, Partial);
3837 void Sema::CheckTemplatePartialSpecialization(
3838 VarTemplatePartialSpecializationDecl *Partial) {
3839 checkTemplatePartialSpecialization(*this, Partial);
3842 void Sema::CheckDeductionGuideTemplate(FunctionTemplateDecl *TD) {
3843 // C++1z [temp.param]p11:
3844 // A template parameter of a deduction guide template that does not have a
3845 // default-argument shall be deducible from the parameter-type-list of the
3846 // deduction guide template.
3847 auto *TemplateParams = TD->getTemplateParameters();
3848 llvm::SmallBitVector DeducibleParams(TemplateParams->size());
3849 MarkDeducedTemplateParameters(TD, DeducibleParams);
3850 for (unsigned I = 0; I != TemplateParams->size(); ++I) {
3851 // A parameter pack is deducible (to an empty pack).
3852 auto *Param = TemplateParams->getParam(I);
3853 if (Param->isParameterPack() || hasVisibleDefaultArgument(Param))
3854 DeducibleParams[I] = true;
3857 if (!DeducibleParams.all()) {
3858 unsigned NumNonDeducible = DeducibleParams.size() - DeducibleParams.count();
3859 Diag(TD->getLocation(), diag::err_deduction_guide_template_not_deducible)
3860 << (NumNonDeducible > 1);
3861 noteNonDeducibleParameters(*this, TemplateParams, DeducibleParams);
3865 DeclResult Sema::ActOnVarTemplateSpecialization(
3866 Scope *S, Declarator &D, TypeSourceInfo *DI, SourceLocation TemplateKWLoc,
3867 TemplateParameterList *TemplateParams, StorageClass SC,
3868 bool IsPartialSpecialization) {
3869 // D must be variable template id.
3870 assert(D.getName().getKind() == UnqualifiedIdKind::IK_TemplateId &&
3871 "Variable template specialization is declared with a template it.");
3873 TemplateIdAnnotation *TemplateId = D.getName().TemplateId;
3874 TemplateArgumentListInfo TemplateArgs =
3875 makeTemplateArgumentListInfo(*this, *TemplateId);
3876 SourceLocation TemplateNameLoc = D.getIdentifierLoc();
3877 SourceLocation LAngleLoc = TemplateId->LAngleLoc;
3878 SourceLocation RAngleLoc = TemplateId->RAngleLoc;
3880 TemplateName Name = TemplateId->Template.get();
3882 // The template-id must name a variable template.
3883 VarTemplateDecl *VarTemplate =
3884 dyn_cast_or_null<VarTemplateDecl>(Name.getAsTemplateDecl());
3886 NamedDecl *FnTemplate;
3887 if (auto *OTS = Name.getAsOverloadedTemplate())
3888 FnTemplate = *OTS->begin();
3890 FnTemplate = dyn_cast_or_null<FunctionTemplateDecl>(Name.getAsTemplateDecl());
3892 return Diag(D.getIdentifierLoc(), diag::err_var_spec_no_template_but_method)
3893 << FnTemplate->getDeclName();
3894 return Diag(D.getIdentifierLoc(), diag::err_var_spec_no_template)
3895 << IsPartialSpecialization;
3898 // Check for unexpanded parameter packs in any of the template arguments.
3899 for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I)
3900 if (DiagnoseUnexpandedParameterPack(TemplateArgs[I],
3901 UPPC_PartialSpecialization))
3904 // Check that the template argument list is well-formed for this
3906 SmallVector<TemplateArgument, 4> Converted;
3907 if (CheckTemplateArgumentList(VarTemplate, TemplateNameLoc, TemplateArgs,
3911 // Find the variable template (partial) specialization declaration that
3912 // corresponds to these arguments.
3913 if (IsPartialSpecialization) {
3914 if (CheckTemplatePartialSpecializationArgs(TemplateNameLoc, VarTemplate,
3915 TemplateArgs.size(), Converted))
3918 // FIXME: Move these checks to CheckTemplatePartialSpecializationArgs so we
3919 // also do them during instantiation.
3920 bool InstantiationDependent;
3921 if (!Name.isDependent() &&
3922 !TemplateSpecializationType::anyDependentTemplateArguments(
3923 TemplateArgs.arguments(),
3924 InstantiationDependent)) {
3925 Diag(TemplateNameLoc, diag::err_partial_spec_fully_specialized)
3926 << VarTemplate->getDeclName();
3927 IsPartialSpecialization = false;
3930 if (isSameAsPrimaryTemplate(VarTemplate->getTemplateParameters(),
3932 // C++ [temp.class.spec]p9b3:
3934 // -- The argument list of the specialization shall not be identical
3935 // to the implicit argument list of the primary template.
3936 Diag(TemplateNameLoc, diag::err_partial_spec_args_match_primary_template)
3937 << /*variable template*/ 1
3938 << /*is definition*/(SC != SC_Extern && !CurContext->isRecord())
3939 << FixItHint::CreateRemoval(SourceRange(LAngleLoc, RAngleLoc));
3940 // FIXME: Recover from this by treating the declaration as a redeclaration
3941 // of the primary template.
3946 void *InsertPos = nullptr;
3947 VarTemplateSpecializationDecl *PrevDecl = nullptr;
3949 if (IsPartialSpecialization)
3950 // FIXME: Template parameter list matters too
3951 PrevDecl = VarTemplate->findPartialSpecialization(Converted, InsertPos);
3953 PrevDecl = VarTemplate->findSpecialization(Converted, InsertPos);
3955 VarTemplateSpecializationDecl *Specialization = nullptr;
3957 // Check whether we can declare a variable template specialization in
3958 // the current scope.
3959 if (CheckTemplateSpecializationScope(*this, VarTemplate, PrevDecl,
3961 IsPartialSpecialization))
3964 if (PrevDecl && PrevDecl->getSpecializationKind() == TSK_Undeclared) {
3965 // Since the only prior variable template specialization with these
3966 // arguments was referenced but not declared, reuse that
3967 // declaration node as our own, updating its source location and
3968 // the list of outer template parameters to reflect our new declaration.
3969 Specialization = PrevDecl;
3970 Specialization->setLocation(TemplateNameLoc);
3972 } else if (IsPartialSpecialization) {
3973 // Create a new class template partial specialization declaration node.
3974 VarTemplatePartialSpecializationDecl *PrevPartial =
3975 cast_or_null<VarTemplatePartialSpecializationDecl>(PrevDecl);
3976 VarTemplatePartialSpecializationDecl *Partial =
3977 VarTemplatePartialSpecializationDecl::Create(
3978 Context, VarTemplate->getDeclContext(), TemplateKWLoc,
3979 TemplateNameLoc, TemplateParams, VarTemplate, DI->getType(), DI, SC,
3980 Converted, TemplateArgs);
3983 VarTemplate->AddPartialSpecialization(Partial, InsertPos);
3984 Specialization = Partial;
3986 // If we are providing an explicit specialization of a member variable
3987 // template specialization, make a note of that.
3988 if (PrevPartial && PrevPartial->getInstantiatedFromMember())
3989 PrevPartial->setMemberSpecialization();
3991 CheckTemplatePartialSpecialization(Partial);
3993 // Create a new class template specialization declaration node for
3994 // this explicit specialization or friend declaration.
3995 Specialization = VarTemplateSpecializationDecl::Create(
3996 Context, VarTemplate->getDeclContext(), TemplateKWLoc, TemplateNameLoc,
3997 VarTemplate, DI->getType(), DI, SC, Converted);
3998 Specialization->setTemplateArgsInfo(TemplateArgs);
4001 VarTemplate->AddSpecialization(Specialization, InsertPos);
4004 // C++ [temp.expl.spec]p6:
4005 // If a template, a member template or the member of a class template is
4006 // explicitly specialized then that specialization shall be declared
4007 // before the first use of that specialization that would cause an implicit
4008 // instantiation to take place, in every translation unit in which such a
4009 // use occurs; no diagnostic is required.
4010 if (PrevDecl && PrevDecl->getPointOfInstantiation().isValid()) {
4012 for (Decl *Prev = PrevDecl; Prev; Prev = Prev->getPreviousDecl()) {
4013 // Is there any previous explicit specialization declaration?
4014 if (getTemplateSpecializationKind(Prev) == TSK_ExplicitSpecialization) {
4021 SourceRange Range(TemplateNameLoc, RAngleLoc);
4022 Diag(TemplateNameLoc, diag::err_specialization_after_instantiation)
4025 Diag(PrevDecl->getPointOfInstantiation(),
4026 diag::note_instantiation_required_here)
4027 << (PrevDecl->getTemplateSpecializationKind() !=
4028 TSK_ImplicitInstantiation);
4033 Specialization->setTemplateKeywordLoc(TemplateKWLoc);
4034 Specialization->setLexicalDeclContext(CurContext);
4036 // Add the specialization into its lexical context, so that it can
4037 // be seen when iterating through the list of declarations in that
4038 // context. However, specializations are not found by name lookup.
4039 CurContext->addDecl(Specialization);
4041 // Note that this is an explicit specialization.
4042 Specialization->setSpecializationKind(TSK_ExplicitSpecialization);
4045 // Check that this isn't a redefinition of this specialization,
4046 // merging with previous declarations.
4047 LookupResult PrevSpec(*this, GetNameForDeclarator(D), LookupOrdinaryName,
4048 forRedeclarationInCurContext());
4049 PrevSpec.addDecl(PrevDecl);
4050 D.setRedeclaration(CheckVariableDeclaration(Specialization, PrevSpec));
4051 } else if (Specialization->isStaticDataMember() &&
4052 Specialization->isOutOfLine()) {
4053 Specialization->setAccess(VarTemplate->getAccess());
4056 return Specialization;
4060 /// A partial specialization whose template arguments have matched
4061 /// a given template-id.
4062 struct PartialSpecMatchResult {
4063 VarTemplatePartialSpecializationDecl *Partial;
4064 TemplateArgumentList *Args;
4066 } // end anonymous namespace
4069 Sema::CheckVarTemplateId(VarTemplateDecl *Template, SourceLocation TemplateLoc,
4070 SourceLocation TemplateNameLoc,
4071 const TemplateArgumentListInfo &TemplateArgs) {
4072 assert(Template && "A variable template id without template?");
4074 // Check that the template argument list is well-formed for this template.
4075 SmallVector<TemplateArgument, 4> Converted;
4076 if (CheckTemplateArgumentList(
4077 Template, TemplateNameLoc,
4078 const_cast<TemplateArgumentListInfo &>(TemplateArgs), false,
4082 // Find the variable template specialization declaration that
4083 // corresponds to these arguments.
4084 void *InsertPos = nullptr;
4085 if (VarTemplateSpecializationDecl *Spec = Template->findSpecialization(
4086 Converted, InsertPos)) {
4087 checkSpecializationVisibility(TemplateNameLoc, Spec);
4088 // If we already have a variable template specialization, return it.
4092 // This is the first time we have referenced this variable template
4093 // specialization. Create the canonical declaration and add it to
4094 // the set of specializations, based on the closest partial specialization
4095 // that it represents. That is,
4096 VarDecl *InstantiationPattern = Template->getTemplatedDecl();
4097 TemplateArgumentList TemplateArgList(TemplateArgumentList::OnStack,
4099 TemplateArgumentList *InstantiationArgs = &TemplateArgList;
4100 bool AmbiguousPartialSpec = false;
4101 typedef PartialSpecMatchResult MatchResult;
4102 SmallVector<MatchResult, 4> Matched;
4103 SourceLocation PointOfInstantiation = TemplateNameLoc;
4104 TemplateSpecCandidateSet FailedCandidates(PointOfInstantiation,
4105 /*ForTakingAddress=*/false);
4107 // 1. Attempt to find the closest partial specialization that this
4108 // specializes, if any.
4109 // If any of the template arguments is dependent, then this is probably
4110 // a placeholder for an incomplete declarative context; which must be
4111 // complete by instantiation time. Thus, do not search through the partial
4112 // specializations yet.
4113 // TODO: Unify with InstantiateClassTemplateSpecialization()?
4114 // Perhaps better after unification of DeduceTemplateArguments() and
4115 // getMoreSpecializedPartialSpecialization().
4116 bool InstantiationDependent = false;
4117 if (!TemplateSpecializationType::anyDependentTemplateArguments(
4118 TemplateArgs, InstantiationDependent)) {
4120 SmallVector<VarTemplatePartialSpecializationDecl *, 4> PartialSpecs;
4121 Template->getPartialSpecializations(PartialSpecs);
4123 for (unsigned I = 0, N = PartialSpecs.size(); I != N; ++I) {
4124 VarTemplatePartialSpecializationDecl *Partial = PartialSpecs[I];
4125 TemplateDeductionInfo Info(FailedCandidates.getLocation());
4127 if (TemplateDeductionResult Result =
4128 DeduceTemplateArguments(Partial, TemplateArgList, Info)) {
4129 // Store the failed-deduction information for use in diagnostics, later.
4130 // TODO: Actually use the failed-deduction info?
4131 FailedCandidates.addCandidate().set(
4132 DeclAccessPair::make(Template, AS_public), Partial,
4133 MakeDeductionFailureInfo(Context, Result, Info));
4136 Matched.push_back(PartialSpecMatchResult());
4137 Matched.back().Partial = Partial;
4138 Matched.back().Args = Info.take();
4142 if (Matched.size() >= 1) {
4143 SmallVector<MatchResult, 4>::iterator Best = Matched.begin();
4144 if (Matched.size() == 1) {
4145 // -- If exactly one matching specialization is found, the
4146 // instantiation is generated from that specialization.
4147 // We don't need to do anything for this.
4149 // -- If more than one matching specialization is found, the
4150 // partial order rules (14.5.4.2) are used to determine
4151 // whether one of the specializations is more specialized
4152 // than the others. If none of the specializations is more
4153 // specialized than all of the other matching
4154 // specializations, then the use of the variable template is
4155 // ambiguous and the program is ill-formed.
4156 for (SmallVector<MatchResult, 4>::iterator P = Best + 1,
4157 PEnd = Matched.end();
4159 if (getMoreSpecializedPartialSpecialization(P->Partial, Best->Partial,
4160 PointOfInstantiation) ==
4165 // Determine if the best partial specialization is more specialized than
4167 for (SmallVector<MatchResult, 4>::iterator P = Matched.begin(),
4168 PEnd = Matched.end();
4170 if (P != Best && getMoreSpecializedPartialSpecialization(
4171 P->Partial, Best->Partial,
4172 PointOfInstantiation) != Best->Partial) {
4173 AmbiguousPartialSpec = true;
4179 // Instantiate using the best variable template partial specialization.
4180 InstantiationPattern = Best->Partial;
4181 InstantiationArgs = Best->Args;
4183 // -- If no match is found, the instantiation is generated
4184 // from the primary template.
4185 // InstantiationPattern = Template->getTemplatedDecl();
4189 // 2. Create the canonical declaration.
4190 // Note that we do not instantiate a definition until we see an odr-use
4191 // in DoMarkVarDeclReferenced().
4192 // FIXME: LateAttrs et al.?
4193 VarTemplateSpecializationDecl *Decl = BuildVarTemplateInstantiation(
4194 Template, InstantiationPattern, *InstantiationArgs, TemplateArgs,
4195 Converted, TemplateNameLoc, InsertPos /*, LateAttrs, StartingScope*/);
4199 if (AmbiguousPartialSpec) {
4200 // Partial ordering did not produce a clear winner. Complain.
4201 Decl->setInvalidDecl();
4202 Diag(PointOfInstantiation, diag::err_partial_spec_ordering_ambiguous)
4205 // Print the matching partial specializations.
4206 for (MatchResult P : Matched)
4207 Diag(P.Partial->getLocation(), diag::note_partial_spec_match)
4208 << getTemplateArgumentBindingsText(P.Partial->getTemplateParameters(),
4213 if (VarTemplatePartialSpecializationDecl *D =
4214 dyn_cast<VarTemplatePartialSpecializationDecl>(InstantiationPattern))
4215 Decl->setInstantiationOf(D, InstantiationArgs);
4217 checkSpecializationVisibility(TemplateNameLoc, Decl);
4219 assert(Decl && "No variable template specialization?");
4224 Sema::CheckVarTemplateId(const CXXScopeSpec &SS,
4225 const DeclarationNameInfo &NameInfo,
4226 VarTemplateDecl *Template, SourceLocation TemplateLoc,
4227 const TemplateArgumentListInfo *TemplateArgs) {
4229 DeclResult Decl = CheckVarTemplateId(Template, TemplateLoc, NameInfo.getLoc(),
4231 if (Decl.isInvalid())
4234 VarDecl *Var = cast<VarDecl>(Decl.get());
4235 if (!Var->getTemplateSpecializationKind())
4236 Var->setTemplateSpecializationKind(TSK_ImplicitInstantiation,
4239 // Build an ordinary singleton decl ref.
4240 return BuildDeclarationNameExpr(SS, NameInfo, Var,
4241 /*FoundD=*/nullptr, TemplateArgs);
4244 void Sema::diagnoseMissingTemplateArguments(TemplateName Name,
4245 SourceLocation Loc) {
4246 Diag(Loc, diag::err_template_missing_args)
4247 << (int)getTemplateNameKindForDiagnostics(Name) << Name;
4248 if (TemplateDecl *TD = Name.getAsTemplateDecl()) {
4249 Diag(TD->getLocation(), diag::note_template_decl_here)
4250 << TD->getTemplateParameters()->getSourceRange();
4255 Sema::CheckConceptTemplateId(const CXXScopeSpec &SS,
4256 const DeclarationNameInfo &NameInfo,
4257 ConceptDecl *Template,
4258 SourceLocation TemplateLoc,
4259 const TemplateArgumentListInfo *TemplateArgs) {
4260 // TODO: Do concept specialization here.
4261 Diag(NameInfo.getBeginLoc(), diag::err_concept_not_implemented) <<
4262 "concept specialization";
4266 ExprResult Sema::BuildTemplateIdExpr(const CXXScopeSpec &SS,
4267 SourceLocation TemplateKWLoc,
4270 const TemplateArgumentListInfo *TemplateArgs) {
4271 // FIXME: Can we do any checking at this point? I guess we could check the
4272 // template arguments that we have against the template name, if the template
4273 // name refers to a single template. That's not a terribly common case,
4275 // foo<int> could identify a single function unambiguously
4276 // This approach does NOT work, since f<int>(1);
4277 // gets resolved prior to resorting to overload resolution
4278 // i.e., template<class T> void f(double);
4279 // vs template<class T, class U> void f(U);
4281 // These should be filtered out by our callers.
4282 assert(!R.isAmbiguous() && "ambiguous lookup when building templateid");
4284 // Non-function templates require a template argument list.
4285 if (auto *TD = R.getAsSingle<TemplateDecl>()) {
4286 if (!TemplateArgs && !isa<FunctionTemplateDecl>(TD)) {
4287 diagnoseMissingTemplateArguments(TemplateName(TD), R.getNameLoc());
4292 auto AnyDependentArguments = [&]() -> bool {
4293 bool InstantiationDependent;
4294 return TemplateArgs &&
4295 TemplateSpecializationType::anyDependentTemplateArguments(
4296 *TemplateArgs, InstantiationDependent);
4299 // In C++1y, check variable template ids.
4300 if (R.getAsSingle<VarTemplateDecl>() && !AnyDependentArguments()) {
4301 return CheckVarTemplateId(SS, R.getLookupNameInfo(),
4302 R.getAsSingle<VarTemplateDecl>(),
4303 TemplateKWLoc, TemplateArgs);
4306 if (R.getAsSingle<ConceptDecl>() && !AnyDependentArguments()) {
4307 return CheckConceptTemplateId(SS, R.getLookupNameInfo(),
4308 R.getAsSingle<ConceptDecl>(),
4309 TemplateKWLoc, TemplateArgs);
4312 // We don't want lookup warnings at this point.
4313 R.suppressDiagnostics();
4315 UnresolvedLookupExpr *ULE
4316 = UnresolvedLookupExpr::Create(Context, R.getNamingClass(),
4317 SS.getWithLocInContext(Context),
4319 R.getLookupNameInfo(),
4320 RequiresADL, TemplateArgs,
4321 R.begin(), R.end());
4326 // We actually only call this from template instantiation.
4328 Sema::BuildQualifiedTemplateIdExpr(CXXScopeSpec &SS,
4329 SourceLocation TemplateKWLoc,
4330 const DeclarationNameInfo &NameInfo,
4331 const TemplateArgumentListInfo *TemplateArgs) {
4333 assert(TemplateArgs || TemplateKWLoc.isValid());
4335 if (!(DC = computeDeclContext(SS, false)) ||
4336 DC->isDependentContext() ||
4337 RequireCompleteDeclContext(SS, DC))
4338 return BuildDependentDeclRefExpr(SS, TemplateKWLoc, NameInfo, TemplateArgs);
4340 bool MemberOfUnknownSpecialization;
4341 LookupResult R(*this, NameInfo, LookupOrdinaryName);
4342 if (LookupTemplateName(R, (Scope *)nullptr, SS, QualType(),
4343 /*Entering*/false, MemberOfUnknownSpecialization,
4347 if (R.isAmbiguous())
4351 Diag(NameInfo.getLoc(), diag::err_no_member)
4352 << NameInfo.getName() << DC << SS.getRange();
4356 if (ClassTemplateDecl *Temp = R.getAsSingle<ClassTemplateDecl>()) {
4357 Diag(NameInfo.getLoc(), diag::err_template_kw_refers_to_class_template)
4359 << NameInfo.getName().getAsString() << SS.getRange();
4360 Diag(Temp->getLocation(), diag::note_referenced_class_template);
4364 return BuildTemplateIdExpr(SS, TemplateKWLoc, R, /*ADL*/ false, TemplateArgs);
4367 /// Form a dependent template name.
4369 /// This action forms a dependent template name given the template
4370 /// name and its (presumably dependent) scope specifier. For
4371 /// example, given "MetaFun::template apply", the scope specifier \p
4372 /// SS will be "MetaFun::", \p TemplateKWLoc contains the location
4373 /// of the "template" keyword, and "apply" is the \p Name.
4374 TemplateNameKind Sema::ActOnDependentTemplateName(Scope *S,
4376 SourceLocation TemplateKWLoc,
4377 const UnqualifiedId &Name,
4378 ParsedType ObjectType,
4379 bool EnteringContext,
4381 bool AllowInjectedClassName) {
4382 if (TemplateKWLoc.isValid() && S && !S->getTemplateParamParent())
4384 getLangOpts().CPlusPlus11 ?
4385 diag::warn_cxx98_compat_template_outside_of_template :
4386 diag::ext_template_outside_of_template)
4387 << FixItHint::CreateRemoval(TemplateKWLoc);
4389 DeclContext *LookupCtx = nullptr;
4391 LookupCtx = computeDeclContext(SS, EnteringContext);
4392 if (!LookupCtx && ObjectType)
4393 LookupCtx = computeDeclContext(ObjectType.get());
4395 // C++0x [temp.names]p5:
4396 // If a name prefixed by the keyword template is not the name of
4397 // a template, the program is ill-formed. [Note: the keyword
4398 // template may not be applied to non-template members of class
4399 // templates. -end note ] [ Note: as is the case with the
4400 // typename prefix, the template prefix is allowed in cases
4401 // where it is not strictly necessary; i.e., when the
4402 // nested-name-specifier or the expression on the left of the ->
4403 // or . is not dependent on a template-parameter, or the use
4404 // does not appear in the scope of a template. -end note]
4406 // Note: C++03 was more strict here, because it banned the use of
4407 // the "template" keyword prior to a template-name that was not a
4408 // dependent name. C++ DR468 relaxed this requirement (the
4409 // "template" keyword is now permitted). We follow the C++0x
4410 // rules, even in C++03 mode with a warning, retroactively applying the DR.
4411 bool MemberOfUnknownSpecialization;
4412 TemplateNameKind TNK = isTemplateName(S, SS, TemplateKWLoc.isValid(), Name,
4413 ObjectType, EnteringContext, Result,
4414 MemberOfUnknownSpecialization);
4415 if (TNK == TNK_Non_template && MemberOfUnknownSpecialization) {
4416 // This is a dependent template. Handle it below.
4417 } else if (TNK == TNK_Non_template) {
4418 // Do the lookup again to determine if this is a "nothing found" case or
4419 // a "not a template" case. FIXME: Refactor isTemplateName so we don't
4421 DeclarationNameInfo DNI = GetNameFromUnqualifiedId(Name);
4422 LookupResult R(*this, DNI.getName(), Name.getBeginLoc(),
4423 LookupOrdinaryName);
4425 if (!LookupTemplateName(R, S, SS, ObjectType.get(), EnteringContext,
4426 MOUS, TemplateKWLoc) && !R.isAmbiguous())
4427 Diag(Name.getBeginLoc(), diag::err_no_member)
4428 << DNI.getName() << LookupCtx << SS.getRange();
4429 return TNK_Non_template;
4431 // We found something; return it.
4432 auto *LookupRD = dyn_cast<CXXRecordDecl>(LookupCtx);
4433 if (!AllowInjectedClassName && SS.isSet() && LookupRD &&
4434 Name.getKind() == UnqualifiedIdKind::IK_Identifier &&
4435 Name.Identifier && LookupRD->getIdentifier() == Name.Identifier) {
4436 // C++14 [class.qual]p2:
4437 // In a lookup in which function names are not ignored and the
4438 // nested-name-specifier nominates a class C, if the name specified
4439 // [...] is the injected-class-name of C, [...] the name is instead
4440 // considered to name the constructor
4442 // We don't get here if naming the constructor would be valid, so we
4443 // just reject immediately and recover by treating the
4444 // injected-class-name as naming the template.
4445 Diag(Name.getBeginLoc(),
4446 diag::ext_out_of_line_qualified_id_type_names_constructor)
4448 << 0 /*injected-class-name used as template name*/
4449 << 1 /*'template' keyword was used*/;
4455 NestedNameSpecifier *Qualifier = SS.getScopeRep();
4457 switch (Name.getKind()) {
4458 case UnqualifiedIdKind::IK_Identifier:
4459 Result = TemplateTy::make(Context.getDependentTemplateName(Qualifier,
4461 return TNK_Dependent_template_name;
4463 case UnqualifiedIdKind::IK_OperatorFunctionId:
4464 Result = TemplateTy::make(Context.getDependentTemplateName(Qualifier,
4465 Name.OperatorFunctionId.Operator));
4466 return TNK_Function_template;
4468 case UnqualifiedIdKind::IK_LiteralOperatorId:
4469 llvm_unreachable("literal operator id cannot have a dependent scope");
4475 Diag(Name.getBeginLoc(), diag::err_template_kw_refers_to_non_template)
4476 << GetNameFromUnqualifiedId(Name).getName() << Name.getSourceRange()
4478 return TNK_Non_template;
4481 bool Sema::CheckTemplateTypeArgument(TemplateTypeParmDecl *Param,
4482 TemplateArgumentLoc &AL,
4483 SmallVectorImpl<TemplateArgument> &Converted) {
4484 const TemplateArgument &Arg = AL.getArgument();
4486 TypeSourceInfo *TSI = nullptr;
4488 // Check template type parameter.
4489 switch(Arg.getKind()) {
4490 case TemplateArgument::Type:
4491 // C++ [temp.arg.type]p1:
4492 // A template-argument for a template-parameter which is a
4493 // type shall be a type-id.
4494 ArgType = Arg.getAsType();
4495 TSI = AL.getTypeSourceInfo();
4497 case TemplateArgument::Template:
4498 case TemplateArgument::TemplateExpansion: {
4499 // We have a template type parameter but the template argument
4500 // is a template without any arguments.
4501 SourceRange SR = AL.getSourceRange();
4502 TemplateName Name = Arg.getAsTemplateOrTemplatePattern();
4503 diagnoseMissingTemplateArguments(Name, SR.getEnd());
4506 case TemplateArgument::Expression: {
4507 // We have a template type parameter but the template argument is an
4508 // expression; see if maybe it is missing the "typename" keyword.
4510 DeclarationNameInfo NameInfo;
4512 if (DeclRefExpr *ArgExpr = dyn_cast<DeclRefExpr>(Arg.getAsExpr())) {
4513 SS.Adopt(ArgExpr->getQualifierLoc());
4514 NameInfo = ArgExpr->getNameInfo();
4515 } else if (DependentScopeDeclRefExpr *ArgExpr =
4516 dyn_cast<DependentScopeDeclRefExpr>(Arg.getAsExpr())) {
4517 SS.Adopt(ArgExpr->getQualifierLoc());
4518 NameInfo = ArgExpr->getNameInfo();
4519 } else if (CXXDependentScopeMemberExpr *ArgExpr =
4520 dyn_cast<CXXDependentScopeMemberExpr>(Arg.getAsExpr())) {
4521 if (ArgExpr->isImplicitAccess()) {
4522 SS.Adopt(ArgExpr->getQualifierLoc());
4523 NameInfo = ArgExpr->getMemberNameInfo();
4527 if (auto *II = NameInfo.getName().getAsIdentifierInfo()) {
4528 LookupResult Result(*this, NameInfo, LookupOrdinaryName);
4529 LookupParsedName(Result, CurScope, &SS);
4531 if (Result.getAsSingle<TypeDecl>() ||
4532 Result.getResultKind() ==
4533 LookupResult::NotFoundInCurrentInstantiation) {
4534 // Suggest that the user add 'typename' before the NNS.
4535 SourceLocation Loc = AL.getSourceRange().getBegin();
4536 Diag(Loc, getLangOpts().MSVCCompat
4537 ? diag::ext_ms_template_type_arg_missing_typename
4538 : diag::err_template_arg_must_be_type_suggest)
4539 << FixItHint::CreateInsertion(Loc, "typename ");
4540 Diag(Param->getLocation(), diag::note_template_param_here);
4542 // Recover by synthesizing a type using the location information that we
4545 Context.getDependentNameType(ETK_Typename, SS.getScopeRep(), II);
4547 DependentNameTypeLoc TL = TLB.push<DependentNameTypeLoc>(ArgType);
4548 TL.setElaboratedKeywordLoc(SourceLocation(/*synthesized*/));
4549 TL.setQualifierLoc(SS.getWithLocInContext(Context));
4550 TL.setNameLoc(NameInfo.getLoc());
4551 TSI = TLB.getTypeSourceInfo(Context, ArgType);
4553 // Overwrite our input TemplateArgumentLoc so that we can recover
4555 AL = TemplateArgumentLoc(TemplateArgument(ArgType),
4556 TemplateArgumentLocInfo(TSI));
4565 // We have a template type parameter but the template argument
4567 SourceRange SR = AL.getSourceRange();
4568 Diag(SR.getBegin(), diag::err_template_arg_must_be_type) << SR;
4569 Diag(Param->getLocation(), diag::note_template_param_here);
4575 if (CheckTemplateArgument(Param, TSI))
4578 // Add the converted template type argument.
4579 ArgType = Context.getCanonicalType(ArgType);
4582 // If an explicitly-specified template argument type is a lifetime type
4583 // with no lifetime qualifier, the __strong lifetime qualifier is inferred.
4584 if (getLangOpts().ObjCAutoRefCount &&
4585 ArgType->isObjCLifetimeType() &&
4586 !ArgType.getObjCLifetime()) {
4588 Qs.setObjCLifetime(Qualifiers::OCL_Strong);
4589 ArgType = Context.getQualifiedType(ArgType, Qs);
4592 Converted.push_back(TemplateArgument(ArgType));
4596 /// Substitute template arguments into the default template argument for
4597 /// the given template type parameter.
4599 /// \param SemaRef the semantic analysis object for which we are performing
4600 /// the substitution.
4602 /// \param Template the template that we are synthesizing template arguments
4605 /// \param TemplateLoc the location of the template name that started the
4606 /// template-id we are checking.
4608 /// \param RAngleLoc the location of the right angle bracket ('>') that
4609 /// terminates the template-id.
4611 /// \param Param the template template parameter whose default we are
4612 /// substituting into.
4614 /// \param Converted the list of template arguments provided for template
4615 /// parameters that precede \p Param in the template parameter list.
4616 /// \returns the substituted template argument, or NULL if an error occurred.
4617 static TypeSourceInfo *
4618 SubstDefaultTemplateArgument(Sema &SemaRef,
4619 TemplateDecl *Template,
4620 SourceLocation TemplateLoc,
4621 SourceLocation RAngleLoc,
4622 TemplateTypeParmDecl *Param,
4623 SmallVectorImpl<TemplateArgument> &Converted) {
4624 TypeSourceInfo *ArgType = Param->getDefaultArgumentInfo();
4626 // If the argument type is dependent, instantiate it now based
4627 // on the previously-computed template arguments.
4628 if (ArgType->getType()->isInstantiationDependentType()) {
4629 Sema::InstantiatingTemplate Inst(SemaRef, TemplateLoc,
4630 Param, Template, Converted,
4631 SourceRange(TemplateLoc, RAngleLoc));
4632 if (Inst.isInvalid())
4635 TemplateArgumentList TemplateArgs(TemplateArgumentList::OnStack, Converted);
4637 // Only substitute for the innermost template argument list.
4638 MultiLevelTemplateArgumentList TemplateArgLists;
4639 TemplateArgLists.addOuterTemplateArguments(&TemplateArgs);
4640 for (unsigned i = 0, e = Param->getDepth(); i != e; ++i)
4641 TemplateArgLists.addOuterTemplateArguments(None);
4643 Sema::ContextRAII SavedContext(SemaRef, Template->getDeclContext());
4645 SemaRef.SubstType(ArgType, TemplateArgLists,
4646 Param->getDefaultArgumentLoc(), Param->getDeclName());
4652 /// Substitute template arguments into the default template argument for
4653 /// the given non-type template parameter.
4655 /// \param SemaRef the semantic analysis object for which we are performing
4656 /// the substitution.
4658 /// \param Template the template that we are synthesizing template arguments
4661 /// \param TemplateLoc the location of the template name that started the
4662 /// template-id we are checking.
4664 /// \param RAngleLoc the location of the right angle bracket ('>') that
4665 /// terminates the template-id.
4667 /// \param Param the non-type template parameter whose default we are
4668 /// substituting into.
4670 /// \param Converted the list of template arguments provided for template
4671 /// parameters that precede \p Param in the template parameter list.
4673 /// \returns the substituted template argument, or NULL if an error occurred.
4675 SubstDefaultTemplateArgument(Sema &SemaRef,
4676 TemplateDecl *Template,
4677 SourceLocation TemplateLoc,
4678 SourceLocation RAngleLoc,
4679 NonTypeTemplateParmDecl *Param,
4680 SmallVectorImpl<TemplateArgument> &Converted) {
4681 Sema::InstantiatingTemplate Inst(SemaRef, TemplateLoc,
4682 Param, Template, Converted,
4683 SourceRange(TemplateLoc, RAngleLoc));
4684 if (Inst.isInvalid())
4687 TemplateArgumentList TemplateArgs(TemplateArgumentList::OnStack, Converted);
4689 // Only substitute for the innermost template argument list.
4690 MultiLevelTemplateArgumentList TemplateArgLists;
4691 TemplateArgLists.addOuterTemplateArguments(&TemplateArgs);
4692 for (unsigned i = 0, e = Param->getDepth(); i != e; ++i)
4693 TemplateArgLists.addOuterTemplateArguments(None);
4695 Sema::ContextRAII SavedContext(SemaRef, Template->getDeclContext());
4696 EnterExpressionEvaluationContext ConstantEvaluated(
4697 SemaRef, Sema::ExpressionEvaluationContext::ConstantEvaluated);
4698 return SemaRef.SubstExpr(Param->getDefaultArgument(), TemplateArgLists);
4701 /// Substitute template arguments into the default template argument for
4702 /// the given template template parameter.
4704 /// \param SemaRef the semantic analysis object for which we are performing
4705 /// the substitution.
4707 /// \param Template the template that we are synthesizing template arguments
4710 /// \param TemplateLoc the location of the template name that started the
4711 /// template-id we are checking.
4713 /// \param RAngleLoc the location of the right angle bracket ('>') that
4714 /// terminates the template-id.
4716 /// \param Param the template template parameter whose default we are
4717 /// substituting into.
4719 /// \param Converted the list of template arguments provided for template
4720 /// parameters that precede \p Param in the template parameter list.
4722 /// \param QualifierLoc Will be set to the nested-name-specifier (with
4723 /// source-location information) that precedes the template name.
4725 /// \returns the substituted template argument, or NULL if an error occurred.
4727 SubstDefaultTemplateArgument(Sema &SemaRef,
4728 TemplateDecl *Template,
4729 SourceLocation TemplateLoc,
4730 SourceLocation RAngleLoc,
4731 TemplateTemplateParmDecl *Param,
4732 SmallVectorImpl<TemplateArgument> &Converted,
4733 NestedNameSpecifierLoc &QualifierLoc) {
4734 Sema::InstantiatingTemplate Inst(
4735 SemaRef, TemplateLoc, TemplateParameter(Param), Template, Converted,
4736 SourceRange(TemplateLoc, RAngleLoc));
4737 if (Inst.isInvalid())
4738 return TemplateName();
4740 TemplateArgumentList TemplateArgs(TemplateArgumentList::OnStack, Converted);
4742 // Only substitute for the innermost template argument list.
4743 MultiLevelTemplateArgumentList TemplateArgLists;
4744 TemplateArgLists.addOuterTemplateArguments(&TemplateArgs);
4745 for (unsigned i = 0, e = Param->getDepth(); i != e; ++i)
4746 TemplateArgLists.addOuterTemplateArguments(None);
4748 Sema::ContextRAII SavedContext(SemaRef, Template->getDeclContext());
4749 // Substitute into the nested-name-specifier first,
4750 QualifierLoc = Param->getDefaultArgument().getTemplateQualifierLoc();
4753 SemaRef.SubstNestedNameSpecifierLoc(QualifierLoc, TemplateArgLists);
4755 return TemplateName();
4758 return SemaRef.SubstTemplateName(
4760 Param->getDefaultArgument().getArgument().getAsTemplate(),
4761 Param->getDefaultArgument().getTemplateNameLoc(),
4765 /// If the given template parameter has a default template
4766 /// argument, substitute into that default template argument and
4767 /// return the corresponding template argument.
4769 Sema::SubstDefaultTemplateArgumentIfAvailable(TemplateDecl *Template,
4770 SourceLocation TemplateLoc,
4771 SourceLocation RAngleLoc,
4773 SmallVectorImpl<TemplateArgument>
4775 bool &HasDefaultArg) {
4776 HasDefaultArg = false;
4778 if (TemplateTypeParmDecl *TypeParm = dyn_cast<TemplateTypeParmDecl>(Param)) {
4779 if (!hasVisibleDefaultArgument(TypeParm))
4780 return TemplateArgumentLoc();
4782 HasDefaultArg = true;
4783 TypeSourceInfo *DI = SubstDefaultTemplateArgument(*this, Template,
4789 return TemplateArgumentLoc(TemplateArgument(DI->getType()), DI);
4791 return TemplateArgumentLoc();
4794 if (NonTypeTemplateParmDecl *NonTypeParm
4795 = dyn_cast<NonTypeTemplateParmDecl>(Param)) {
4796 if (!hasVisibleDefaultArgument(NonTypeParm))
4797 return TemplateArgumentLoc();
4799 HasDefaultArg = true;
4800 ExprResult Arg = SubstDefaultTemplateArgument(*this, Template,
4805 if (Arg.isInvalid())
4806 return TemplateArgumentLoc();
4808 Expr *ArgE = Arg.getAs<Expr>();
4809 return TemplateArgumentLoc(TemplateArgument(ArgE), ArgE);
4812 TemplateTemplateParmDecl *TempTempParm
4813 = cast<TemplateTemplateParmDecl>(Param);
4814 if (!hasVisibleDefaultArgument(TempTempParm))
4815 return TemplateArgumentLoc();
4817 HasDefaultArg = true;
4818 NestedNameSpecifierLoc QualifierLoc;
4819 TemplateName TName = SubstDefaultTemplateArgument(*this, Template,
4826 return TemplateArgumentLoc();
4828 return TemplateArgumentLoc(TemplateArgument(TName),
4829 TempTempParm->getDefaultArgument().getTemplateQualifierLoc(),
4830 TempTempParm->getDefaultArgument().getTemplateNameLoc());
4833 /// Convert a template-argument that we parsed as a type into a template, if
4834 /// possible. C++ permits injected-class-names to perform dual service as
4835 /// template template arguments and as template type arguments.
4836 static TemplateArgumentLoc convertTypeTemplateArgumentToTemplate(TypeLoc TLoc) {
4837 // Extract and step over any surrounding nested-name-specifier.
4838 NestedNameSpecifierLoc QualLoc;
4839 if (auto ETLoc = TLoc.getAs<ElaboratedTypeLoc>()) {
4840 if (ETLoc.getTypePtr()->getKeyword() != ETK_None)
4841 return TemplateArgumentLoc();
4843 QualLoc = ETLoc.getQualifierLoc();
4844 TLoc = ETLoc.getNamedTypeLoc();
4847 // If this type was written as an injected-class-name, it can be used as a
4848 // template template argument.
4849 if (auto InjLoc = TLoc.getAs<InjectedClassNameTypeLoc>())
4850 return TemplateArgumentLoc(InjLoc.getTypePtr()->getTemplateName(),
4851 QualLoc, InjLoc.getNameLoc());
4853 // If this type was written as an injected-class-name, it may have been
4854 // converted to a RecordType during instantiation. If the RecordType is
4855 // *not* wrapped in a TemplateSpecializationType and denotes a class
4856 // template specialization, it must have come from an injected-class-name.
4857 if (auto RecLoc = TLoc.getAs<RecordTypeLoc>())
4859 dyn_cast<ClassTemplateSpecializationDecl>(RecLoc.getDecl()))
4860 return TemplateArgumentLoc(TemplateName(CTSD->getSpecializedTemplate()),
4861 QualLoc, RecLoc.getNameLoc());
4863 return TemplateArgumentLoc();
4866 /// Check that the given template argument corresponds to the given
4867 /// template parameter.
4869 /// \param Param The template parameter against which the argument will be
4872 /// \param Arg The template argument, which may be updated due to conversions.
4874 /// \param Template The template in which the template argument resides.
4876 /// \param TemplateLoc The location of the template name for the template
4877 /// whose argument list we're matching.
4879 /// \param RAngleLoc The location of the right angle bracket ('>') that closes
4880 /// the template argument list.
4882 /// \param ArgumentPackIndex The index into the argument pack where this
4883 /// argument will be placed. Only valid if the parameter is a parameter pack.
4885 /// \param Converted The checked, converted argument will be added to the
4886 /// end of this small vector.
4888 /// \param CTAK Describes how we arrived at this particular template argument:
4889 /// explicitly written, deduced, etc.
4891 /// \returns true on error, false otherwise.
4892 bool Sema::CheckTemplateArgument(NamedDecl *Param,
4893 TemplateArgumentLoc &Arg,
4894 NamedDecl *Template,
4895 SourceLocation TemplateLoc,
4896 SourceLocation RAngleLoc,
4897 unsigned ArgumentPackIndex,
4898 SmallVectorImpl<TemplateArgument> &Converted,
4899 CheckTemplateArgumentKind CTAK) {
4900 // Check template type parameters.
4901 if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(Param))
4902 return CheckTemplateTypeArgument(TTP, Arg, Converted);
4904 // Check non-type template parameters.
4905 if (NonTypeTemplateParmDecl *NTTP =dyn_cast<NonTypeTemplateParmDecl>(Param)) {
4906 // Do substitution on the type of the non-type template parameter
4907 // with the template arguments we've seen thus far. But if the
4908 // template has a dependent context then we cannot substitute yet.
4909 QualType NTTPType = NTTP->getType();
4910 if (NTTP->isParameterPack() && NTTP->isExpandedParameterPack())
4911 NTTPType = NTTP->getExpansionType(ArgumentPackIndex);
4913 // FIXME: Do we need to substitute into parameters here if they're
4914 // instantiation-dependent but not dependent?
4915 if (NTTPType->isDependentType() &&
4916 !isa<TemplateTemplateParmDecl>(Template) &&
4917 !Template->getDeclContext()->isDependentContext()) {
4918 // Do substitution on the type of the non-type template parameter.
4919 InstantiatingTemplate Inst(*this, TemplateLoc, Template,
4921 SourceRange(TemplateLoc, RAngleLoc));
4922 if (Inst.isInvalid())
4925 TemplateArgumentList TemplateArgs(TemplateArgumentList::OnStack,
4928 // If the parameter is a pack expansion, expand this slice of the pack.
4929 if (auto *PET = NTTPType->getAs<PackExpansionType>()) {
4930 Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(*this,
4932 NTTPType = SubstType(PET->getPattern(),
4933 MultiLevelTemplateArgumentList(TemplateArgs),
4934 NTTP->getLocation(),
4935 NTTP->getDeclName());
4937 NTTPType = SubstType(NTTPType,
4938 MultiLevelTemplateArgumentList(TemplateArgs),
4939 NTTP->getLocation(),
4940 NTTP->getDeclName());
4943 // If that worked, check the non-type template parameter type
4945 if (!NTTPType.isNull())
4946 NTTPType = CheckNonTypeTemplateParameterType(NTTPType,
4947 NTTP->getLocation());
4948 if (NTTPType.isNull())
4952 switch (Arg.getArgument().getKind()) {
4953 case TemplateArgument::Null:
4954 llvm_unreachable("Should never see a NULL template argument here");
4956 case TemplateArgument::Expression: {
4957 TemplateArgument Result;
4958 unsigned CurSFINAEErrors = NumSFINAEErrors;
4960 CheckTemplateArgument(NTTP, NTTPType, Arg.getArgument().getAsExpr(),
4962 if (Res.isInvalid())
4964 // If the current template argument causes an error, give up now.
4965 if (CurSFINAEErrors < NumSFINAEErrors)
4968 // If the resulting expression is new, then use it in place of the
4969 // old expression in the template argument.
4970 if (Res.get() != Arg.getArgument().getAsExpr()) {
4971 TemplateArgument TA(Res.get());
4972 Arg = TemplateArgumentLoc(TA, Res.get());
4975 Converted.push_back(Result);
4979 case TemplateArgument::Declaration:
4980 case TemplateArgument::Integral:
4981 case TemplateArgument::NullPtr:
4982 // We've already checked this template argument, so just copy
4983 // it to the list of converted arguments.
4984 Converted.push_back(Arg.getArgument());
4987 case TemplateArgument::Template:
4988 case TemplateArgument::TemplateExpansion:
4989 // We were given a template template argument. It may not be ill-formed;
4991 if (DependentTemplateName *DTN
4992 = Arg.getArgument().getAsTemplateOrTemplatePattern()
4993 .getAsDependentTemplateName()) {
4994 // We have a template argument such as \c T::template X, which we
4995 // parsed as a template template argument. However, since we now
4996 // know that we need a non-type template argument, convert this
4997 // template name into an expression.
4999 DeclarationNameInfo NameInfo(DTN->getIdentifier(),
5000 Arg.getTemplateNameLoc());
5003 SS.Adopt(Arg.getTemplateQualifierLoc());
5004 // FIXME: the template-template arg was a DependentTemplateName,
5005 // so it was provided with a template keyword. However, its source
5006 // location is not stored in the template argument structure.
5007 SourceLocation TemplateKWLoc;
5008 ExprResult E = DependentScopeDeclRefExpr::Create(
5009 Context, SS.getWithLocInContext(Context), TemplateKWLoc, NameInfo,
5012 // If we parsed the template argument as a pack expansion, create a
5013 // pack expansion expression.
5014 if (Arg.getArgument().getKind() == TemplateArgument::TemplateExpansion){
5015 E = ActOnPackExpansion(E.get(), Arg.getTemplateEllipsisLoc());
5020 TemplateArgument Result;
5021 E = CheckTemplateArgument(NTTP, NTTPType, E.get(), Result);
5025 Converted.push_back(Result);
5029 // We have a template argument that actually does refer to a class
5030 // template, alias template, or template template parameter, and
5031 // therefore cannot be a non-type template argument.
5032 Diag(Arg.getLocation(), diag::err_template_arg_must_be_expr)
5033 << Arg.getSourceRange();
5035 Diag(Param->getLocation(), diag::note_template_param_here);
5038 case TemplateArgument::Type: {
5039 // We have a non-type template parameter but the template
5040 // argument is a type.
5042 // C++ [temp.arg]p2:
5043 // In a template-argument, an ambiguity between a type-id and
5044 // an expression is resolved to a type-id, regardless of the
5045 // form of the corresponding template-parameter.
5047 // We warn specifically about this case, since it can be rather
5048 // confusing for users.
5049 QualType T = Arg.getArgument().getAsType();
5050 SourceRange SR = Arg.getSourceRange();
5051 if (T->isFunctionType())
5052 Diag(SR.getBegin(), diag::err_template_arg_nontype_ambig) << SR << T;
5054 Diag(SR.getBegin(), diag::err_template_arg_must_be_expr) << SR;
5055 Diag(Param->getLocation(), diag::note_template_param_here);
5059 case TemplateArgument::Pack:
5060 llvm_unreachable("Caller must expand template argument packs");
5067 // Check template template parameters.
5068 TemplateTemplateParmDecl *TempParm = cast<TemplateTemplateParmDecl>(Param);
5070 TemplateParameterList *Params = TempParm->getTemplateParameters();
5071 if (TempParm->isExpandedParameterPack())
5072 Params = TempParm->getExpansionTemplateParameters(ArgumentPackIndex);
5074 // Substitute into the template parameter list of the template
5075 // template parameter, since previously-supplied template arguments
5076 // may appear within the template template parameter.
5078 // FIXME: Skip this if the parameters aren't instantiation-dependent.
5080 // Set up a template instantiation context.
5081 LocalInstantiationScope Scope(*this);
5082 InstantiatingTemplate Inst(*this, TemplateLoc, Template,
5083 TempParm, Converted,
5084 SourceRange(TemplateLoc, RAngleLoc));
5085 if (Inst.isInvalid())
5088 TemplateArgumentList TemplateArgs(TemplateArgumentList::OnStack, Converted);
5089 Params = SubstTemplateParams(Params, CurContext,
5090 MultiLevelTemplateArgumentList(TemplateArgs));
5095 // C++1z [temp.local]p1: (DR1004)
5096 // When [the injected-class-name] is used [...] as a template-argument for
5097 // a template template-parameter [...] it refers to the class template
5099 if (Arg.getArgument().getKind() == TemplateArgument::Type) {
5100 TemplateArgumentLoc ConvertedArg = convertTypeTemplateArgumentToTemplate(
5101 Arg.getTypeSourceInfo()->getTypeLoc());
5102 if (!ConvertedArg.getArgument().isNull())
5106 switch (Arg.getArgument().getKind()) {
5107 case TemplateArgument::Null:
5108 llvm_unreachable("Should never see a NULL template argument here");
5110 case TemplateArgument::Template:
5111 case TemplateArgument::TemplateExpansion:
5112 if (CheckTemplateTemplateArgument(Params, Arg))
5115 Converted.push_back(Arg.getArgument());
5118 case TemplateArgument::Expression:
5119 case TemplateArgument::Type:
5120 // We have a template template parameter but the template
5121 // argument does not refer to a template.
5122 Diag(Arg.getLocation(), diag::err_template_arg_must_be_template)
5123 << getLangOpts().CPlusPlus11;
5126 case TemplateArgument::Declaration:
5127 llvm_unreachable("Declaration argument with template template parameter");
5128 case TemplateArgument::Integral:
5129 llvm_unreachable("Integral argument with template template parameter");
5130 case TemplateArgument::NullPtr:
5131 llvm_unreachable("Null pointer argument with template template parameter");
5133 case TemplateArgument::Pack:
5134 llvm_unreachable("Caller must expand template argument packs");
5140 /// Check whether the template parameter is a pack expansion, and if so,
5141 /// determine the number of parameters produced by that expansion. For instance:
5144 /// template<typename ...Ts> struct A {
5145 /// template<Ts ...NTs, template<Ts> class ...TTs, typename ...Us> struct B;
5149 /// In \c A<int,int>::B, \c NTs and \c TTs have expanded pack size 2, and \c Us
5150 /// is not a pack expansion, so returns an empty Optional.
5151 static Optional<unsigned> getExpandedPackSize(NamedDecl *Param) {
5152 if (NonTypeTemplateParmDecl *NTTP
5153 = dyn_cast<NonTypeTemplateParmDecl>(Param)) {
5154 if (NTTP->isExpandedParameterPack())
5155 return NTTP->getNumExpansionTypes();
5158 if (TemplateTemplateParmDecl *TTP
5159 = dyn_cast<TemplateTemplateParmDecl>(Param)) {
5160 if (TTP->isExpandedParameterPack())
5161 return TTP->getNumExpansionTemplateParameters();
5167 /// Diagnose a missing template argument.
5168 template<typename TemplateParmDecl>
5169 static bool diagnoseMissingArgument(Sema &S, SourceLocation Loc,
5171 const TemplateParmDecl *D,
5172 TemplateArgumentListInfo &Args) {
5173 // Dig out the most recent declaration of the template parameter; there may be
5174 // declarations of the template that are more recent than TD.
5175 D = cast<TemplateParmDecl>(cast<TemplateDecl>(TD->getMostRecentDecl())
5176 ->getTemplateParameters()
5177 ->getParam(D->getIndex()));
5179 // If there's a default argument that's not visible, diagnose that we're
5180 // missing a module import.
5181 llvm::SmallVector<Module*, 8> Modules;
5182 if (D->hasDefaultArgument() && !S.hasVisibleDefaultArgument(D, &Modules)) {
5183 S.diagnoseMissingImport(Loc, cast<NamedDecl>(TD),
5184 D->getDefaultArgumentLoc(), Modules,
5185 Sema::MissingImportKind::DefaultArgument,
5190 // FIXME: If there's a more recent default argument that *is* visible,
5191 // diagnose that it was declared too late.
5193 TemplateParameterList *Params = TD->getTemplateParameters();
5195 S.Diag(Loc, diag::err_template_arg_list_different_arity)
5196 << /*not enough args*/0
5197 << (int)S.getTemplateNameKindForDiagnostics(TemplateName(TD))
5199 S.Diag(TD->getLocation(), diag::note_template_decl_here)
5200 << Params->getSourceRange();
5204 /// Check that the given template argument list is well-formed
5205 /// for specializing the given template.
5206 bool Sema::CheckTemplateArgumentList(
5207 TemplateDecl *Template, SourceLocation TemplateLoc,
5208 TemplateArgumentListInfo &TemplateArgs, bool PartialTemplateArgs,
5209 SmallVectorImpl<TemplateArgument> &Converted,
5210 bool UpdateArgsWithConversions) {
5211 // Make a copy of the template arguments for processing. Only make the
5212 // changes at the end when successful in matching the arguments to the
5214 TemplateArgumentListInfo NewArgs = TemplateArgs;
5216 // Make sure we get the template parameter list from the most
5217 // recentdeclaration, since that is the only one that has is guaranteed to
5218 // have all the default template argument information.
5219 TemplateParameterList *Params =
5220 cast<TemplateDecl>(Template->getMostRecentDecl())
5221 ->getTemplateParameters();
5223 SourceLocation RAngleLoc = NewArgs.getRAngleLoc();
5225 // C++ [temp.arg]p1:
5226 // [...] The type and form of each template-argument specified in
5227 // a template-id shall match the type and form specified for the
5228 // corresponding parameter declared by the template in its
5229 // template-parameter-list.
5230 bool isTemplateTemplateParameter = isa<TemplateTemplateParmDecl>(Template);
5231 SmallVector<TemplateArgument, 2> ArgumentPack;
5232 unsigned ArgIdx = 0, NumArgs = NewArgs.size();
5233 LocalInstantiationScope InstScope(*this, true);
5234 for (TemplateParameterList::iterator Param = Params->begin(),
5235 ParamEnd = Params->end();
5236 Param != ParamEnd; /* increment in loop */) {
5237 // If we have an expanded parameter pack, make sure we don't have too
5239 if (Optional<unsigned> Expansions = getExpandedPackSize(*Param)) {
5240 if (*Expansions == ArgumentPack.size()) {
5241 // We're done with this parameter pack. Pack up its arguments and add
5242 // them to the list.
5243 Converted.push_back(
5244 TemplateArgument::CreatePackCopy(Context, ArgumentPack));
5245 ArgumentPack.clear();
5247 // This argument is assigned to the next parameter.
5250 } else if (ArgIdx == NumArgs && !PartialTemplateArgs) {
5251 // Not enough arguments for this parameter pack.
5252 Diag(TemplateLoc, diag::err_template_arg_list_different_arity)
5253 << /*not enough args*/0
5254 << (int)getTemplateNameKindForDiagnostics(TemplateName(Template))
5256 Diag(Template->getLocation(), diag::note_template_decl_here)
5257 << Params->getSourceRange();
5262 if (ArgIdx < NumArgs) {
5263 // Check the template argument we were given.
5264 if (CheckTemplateArgument(*Param, NewArgs[ArgIdx], Template,
5265 TemplateLoc, RAngleLoc,
5266 ArgumentPack.size(), Converted))
5269 bool PackExpansionIntoNonPack =
5270 NewArgs[ArgIdx].getArgument().isPackExpansion() &&
5271 (!(*Param)->isTemplateParameterPack() || getExpandedPackSize(*Param));
5272 if (PackExpansionIntoNonPack && isa<TypeAliasTemplateDecl>(Template)) {
5273 // Core issue 1430: we have a pack expansion as an argument to an
5274 // alias template, and it's not part of a parameter pack. This
5275 // can't be canonicalized, so reject it now.
5276 Diag(NewArgs[ArgIdx].getLocation(),
5277 diag::err_alias_template_expansion_into_fixed_list)
5278 << NewArgs[ArgIdx].getSourceRange();
5279 Diag((*Param)->getLocation(), diag::note_template_param_here);
5283 // We're now done with this argument.
5286 if ((*Param)->isTemplateParameterPack()) {
5287 // The template parameter was a template parameter pack, so take the
5288 // deduced argument and place it on the argument pack. Note that we
5289 // stay on the same template parameter so that we can deduce more
5291 ArgumentPack.push_back(Converted.pop_back_val());
5293 // Move to the next template parameter.
5297 // If we just saw a pack expansion into a non-pack, then directly convert
5298 // the remaining arguments, because we don't know what parameters they'll
5300 if (PackExpansionIntoNonPack) {
5301 if (!ArgumentPack.empty()) {
5302 // If we were part way through filling in an expanded parameter pack,
5303 // fall back to just producing individual arguments.
5304 Converted.insert(Converted.end(),
5305 ArgumentPack.begin(), ArgumentPack.end());
5306 ArgumentPack.clear();
5309 while (ArgIdx < NumArgs) {
5310 Converted.push_back(NewArgs[ArgIdx].getArgument());
5320 // If we're checking a partial template argument list, we're done.
5321 if (PartialTemplateArgs) {
5322 if ((*Param)->isTemplateParameterPack() && !ArgumentPack.empty())
5323 Converted.push_back(
5324 TemplateArgument::CreatePackCopy(Context, ArgumentPack));
5329 // If we have a template parameter pack with no more corresponding
5330 // arguments, just break out now and we'll fill in the argument pack below.
5331 if ((*Param)->isTemplateParameterPack()) {
5332 assert(!getExpandedPackSize(*Param) &&
5333 "Should have dealt with this already");
5335 // A non-expanded parameter pack before the end of the parameter list
5336 // only occurs for an ill-formed template parameter list, unless we've
5337 // got a partial argument list for a function template, so just bail out.
5338 if (Param + 1 != ParamEnd)
5341 Converted.push_back(
5342 TemplateArgument::CreatePackCopy(Context, ArgumentPack));
5343 ArgumentPack.clear();
5349 // Check whether we have a default argument.
5350 TemplateArgumentLoc Arg;
5352 // Retrieve the default template argument from the template
5353 // parameter. For each kind of template parameter, we substitute the
5354 // template arguments provided thus far and any "outer" template arguments
5355 // (when the template parameter was part of a nested template) into
5356 // the default argument.
5357 if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(*Param)) {
5358 if (!hasVisibleDefaultArgument(TTP))
5359 return diagnoseMissingArgument(*this, TemplateLoc, Template, TTP,
5362 TypeSourceInfo *ArgType = SubstDefaultTemplateArgument(*this,
5371 Arg = TemplateArgumentLoc(TemplateArgument(ArgType->getType()),
5373 } else if (NonTypeTemplateParmDecl *NTTP
5374 = dyn_cast<NonTypeTemplateParmDecl>(*Param)) {
5375 if (!hasVisibleDefaultArgument(NTTP))
5376 return diagnoseMissingArgument(*this, TemplateLoc, Template, NTTP,
5379 ExprResult E = SubstDefaultTemplateArgument(*this, Template,
5387 Expr *Ex = E.getAs<Expr>();
5388 Arg = TemplateArgumentLoc(TemplateArgument(Ex), Ex);
5390 TemplateTemplateParmDecl *TempParm
5391 = cast<TemplateTemplateParmDecl>(*Param);
5393 if (!hasVisibleDefaultArgument(TempParm))
5394 return diagnoseMissingArgument(*this, TemplateLoc, Template, TempParm,
5397 NestedNameSpecifierLoc QualifierLoc;
5398 TemplateName Name = SubstDefaultTemplateArgument(*this, Template,
5407 Arg = TemplateArgumentLoc(TemplateArgument(Name), QualifierLoc,
5408 TempParm->getDefaultArgument().getTemplateNameLoc());
5411 // Introduce an instantiation record that describes where we are using
5412 // the default template argument. We're not actually instantiating a
5413 // template here, we just create this object to put a note into the
5415 InstantiatingTemplate Inst(*this, RAngleLoc, Template, *Param, Converted,
5416 SourceRange(TemplateLoc, RAngleLoc));
5417 if (Inst.isInvalid())
5420 // Check the default template argument.
5421 if (CheckTemplateArgument(*Param, Arg, Template, TemplateLoc,
5422 RAngleLoc, 0, Converted))
5425 // Core issue 150 (assumed resolution): if this is a template template
5426 // parameter, keep track of the default template arguments from the
5427 // template definition.
5428 if (isTemplateTemplateParameter)
5429 NewArgs.addArgument(Arg);
5431 // Move to the next template parameter and argument.
5436 // If we're performing a partial argument substitution, allow any trailing
5437 // pack expansions; they might be empty. This can happen even if
5438 // PartialTemplateArgs is false (the list of arguments is complete but
5439 // still dependent).
5440 if (ArgIdx < NumArgs && CurrentInstantiationScope &&
5441 CurrentInstantiationScope->getPartiallySubstitutedPack()) {
5442 while (ArgIdx < NumArgs && NewArgs[ArgIdx].getArgument().isPackExpansion())
5443 Converted.push_back(NewArgs[ArgIdx++].getArgument());
5446 // If we have any leftover arguments, then there were too many arguments.
5447 // Complain and fail.
5448 if (ArgIdx < NumArgs) {
5449 Diag(TemplateLoc, diag::err_template_arg_list_different_arity)
5450 << /*too many args*/1
5451 << (int)getTemplateNameKindForDiagnostics(TemplateName(Template))
5453 << SourceRange(NewArgs[ArgIdx].getLocation(), NewArgs.getRAngleLoc());
5454 Diag(Template->getLocation(), diag::note_template_decl_here)
5455 << Params->getSourceRange();
5459 // No problems found with the new argument list, propagate changes back
5461 if (UpdateArgsWithConversions)
5462 TemplateArgs = std::move(NewArgs);
5468 class UnnamedLocalNoLinkageFinder
5469 : public TypeVisitor<UnnamedLocalNoLinkageFinder, bool>
5474 typedef TypeVisitor<UnnamedLocalNoLinkageFinder, bool> inherited;
5477 UnnamedLocalNoLinkageFinder(Sema &S, SourceRange SR) : S(S), SR(SR) { }
5479 bool Visit(QualType T) {
5480 return T.isNull() ? false : inherited::Visit(T.getTypePtr());
5483 #define TYPE(Class, Parent) \
5484 bool Visit##Class##Type(const Class##Type *);
5485 #define ABSTRACT_TYPE(Class, Parent) \
5486 bool Visit##Class##Type(const Class##Type *) { return false; }
5487 #define NON_CANONICAL_TYPE(Class, Parent) \
5488 bool Visit##Class##Type(const Class##Type *) { return false; }
5489 #include "clang/AST/TypeNodes.def"
5491 bool VisitTagDecl(const TagDecl *Tag);
5492 bool VisitNestedNameSpecifier(NestedNameSpecifier *NNS);
5494 } // end anonymous namespace
5496 bool UnnamedLocalNoLinkageFinder::VisitBuiltinType(const BuiltinType*) {
5500 bool UnnamedLocalNoLinkageFinder::VisitComplexType(const ComplexType* T) {
5501 return Visit(T->getElementType());
5504 bool UnnamedLocalNoLinkageFinder::VisitPointerType(const PointerType* T) {
5505 return Visit(T->getPointeeType());
5508 bool UnnamedLocalNoLinkageFinder::VisitBlockPointerType(
5509 const BlockPointerType* T) {
5510 return Visit(T->getPointeeType());
5513 bool UnnamedLocalNoLinkageFinder::VisitLValueReferenceType(
5514 const LValueReferenceType* T) {
5515 return Visit(T->getPointeeType());
5518 bool UnnamedLocalNoLinkageFinder::VisitRValueReferenceType(
5519 const RValueReferenceType* T) {
5520 return Visit(T->getPointeeType());
5523 bool UnnamedLocalNoLinkageFinder::VisitMemberPointerType(
5524 const MemberPointerType* T) {
5525 return Visit(T->getPointeeType()) || Visit(QualType(T->getClass(), 0));
5528 bool UnnamedLocalNoLinkageFinder::VisitConstantArrayType(
5529 const ConstantArrayType* T) {
5530 return Visit(T->getElementType());
5533 bool UnnamedLocalNoLinkageFinder::VisitIncompleteArrayType(
5534 const IncompleteArrayType* T) {
5535 return Visit(T->getElementType());
5538 bool UnnamedLocalNoLinkageFinder::VisitVariableArrayType(
5539 const VariableArrayType* T) {
5540 return Visit(T->getElementType());
5543 bool UnnamedLocalNoLinkageFinder::VisitDependentSizedArrayType(
5544 const DependentSizedArrayType* T) {
5545 return Visit(T->getElementType());
5548 bool UnnamedLocalNoLinkageFinder::VisitDependentSizedExtVectorType(
5549 const DependentSizedExtVectorType* T) {
5550 return Visit(T->getElementType());
5553 bool UnnamedLocalNoLinkageFinder::VisitDependentAddressSpaceType(
5554 const DependentAddressSpaceType *T) {
5555 return Visit(T->getPointeeType());
5558 bool UnnamedLocalNoLinkageFinder::VisitVectorType(const VectorType* T) {
5559 return Visit(T->getElementType());
5562 bool UnnamedLocalNoLinkageFinder::VisitDependentVectorType(
5563 const DependentVectorType *T) {
5564 return Visit(T->getElementType());
5567 bool UnnamedLocalNoLinkageFinder::VisitExtVectorType(const ExtVectorType* T) {
5568 return Visit(T->getElementType());
5571 bool UnnamedLocalNoLinkageFinder::VisitFunctionProtoType(
5572 const FunctionProtoType* T) {
5573 for (const auto &A : T->param_types()) {
5578 return Visit(T->getReturnType());
5581 bool UnnamedLocalNoLinkageFinder::VisitFunctionNoProtoType(
5582 const FunctionNoProtoType* T) {
5583 return Visit(T->getReturnType());
5586 bool UnnamedLocalNoLinkageFinder::VisitUnresolvedUsingType(
5587 const UnresolvedUsingType*) {
5591 bool UnnamedLocalNoLinkageFinder::VisitTypeOfExprType(const TypeOfExprType*) {
5595 bool UnnamedLocalNoLinkageFinder::VisitTypeOfType(const TypeOfType* T) {
5596 return Visit(T->getUnderlyingType());
5599 bool UnnamedLocalNoLinkageFinder::VisitDecltypeType(const DecltypeType*) {
5603 bool UnnamedLocalNoLinkageFinder::VisitUnaryTransformType(
5604 const UnaryTransformType*) {
5608 bool UnnamedLocalNoLinkageFinder::VisitAutoType(const AutoType *T) {
5609 return Visit(T->getDeducedType());
5612 bool UnnamedLocalNoLinkageFinder::VisitDeducedTemplateSpecializationType(
5613 const DeducedTemplateSpecializationType *T) {
5614 return Visit(T->getDeducedType());
5617 bool UnnamedLocalNoLinkageFinder::VisitRecordType(const RecordType* T) {
5618 return VisitTagDecl(T->getDecl());
5621 bool UnnamedLocalNoLinkageFinder::VisitEnumType(const EnumType* T) {
5622 return VisitTagDecl(T->getDecl());
5625 bool UnnamedLocalNoLinkageFinder::VisitTemplateTypeParmType(
5626 const TemplateTypeParmType*) {
5630 bool UnnamedLocalNoLinkageFinder::VisitSubstTemplateTypeParmPackType(
5631 const SubstTemplateTypeParmPackType *) {
5635 bool UnnamedLocalNoLinkageFinder::VisitTemplateSpecializationType(
5636 const TemplateSpecializationType*) {
5640 bool UnnamedLocalNoLinkageFinder::VisitInjectedClassNameType(
5641 const InjectedClassNameType* T) {
5642 return VisitTagDecl(T->getDecl());
5645 bool UnnamedLocalNoLinkageFinder::VisitDependentNameType(
5646 const DependentNameType* T) {
5647 return VisitNestedNameSpecifier(T->getQualifier());
5650 bool UnnamedLocalNoLinkageFinder::VisitDependentTemplateSpecializationType(
5651 const DependentTemplateSpecializationType* T) {
5652 return VisitNestedNameSpecifier(T->getQualifier());
5655 bool UnnamedLocalNoLinkageFinder::VisitPackExpansionType(
5656 const PackExpansionType* T) {
5657 return Visit(T->getPattern());
5660 bool UnnamedLocalNoLinkageFinder::VisitObjCObjectType(const ObjCObjectType *) {
5664 bool UnnamedLocalNoLinkageFinder::VisitObjCInterfaceType(
5665 const ObjCInterfaceType *) {
5669 bool UnnamedLocalNoLinkageFinder::VisitObjCObjectPointerType(
5670 const ObjCObjectPointerType *) {
5674 bool UnnamedLocalNoLinkageFinder::VisitAtomicType(const AtomicType* T) {
5675 return Visit(T->getValueType());
5678 bool UnnamedLocalNoLinkageFinder::VisitPipeType(const PipeType* T) {
5682 bool UnnamedLocalNoLinkageFinder::VisitTagDecl(const TagDecl *Tag) {
5683 if (Tag->getDeclContext()->isFunctionOrMethod()) {
5684 S.Diag(SR.getBegin(),
5685 S.getLangOpts().CPlusPlus11 ?
5686 diag::warn_cxx98_compat_template_arg_local_type :
5687 diag::ext_template_arg_local_type)
5688 << S.Context.getTypeDeclType(Tag) << SR;
5692 if (!Tag->hasNameForLinkage()) {
5693 S.Diag(SR.getBegin(),
5694 S.getLangOpts().CPlusPlus11 ?
5695 diag::warn_cxx98_compat_template_arg_unnamed_type :
5696 diag::ext_template_arg_unnamed_type) << SR;
5697 S.Diag(Tag->getLocation(), diag::note_template_unnamed_type_here);
5704 bool UnnamedLocalNoLinkageFinder::VisitNestedNameSpecifier(
5705 NestedNameSpecifier *NNS) {
5706 if (NNS->getPrefix() && VisitNestedNameSpecifier(NNS->getPrefix()))
5709 switch (NNS->getKind()) {
5710 case NestedNameSpecifier::Identifier:
5711 case NestedNameSpecifier::Namespace:
5712 case NestedNameSpecifier::NamespaceAlias:
5713 case NestedNameSpecifier::Global:
5714 case NestedNameSpecifier::Super:
5717 case NestedNameSpecifier::TypeSpec:
5718 case NestedNameSpecifier::TypeSpecWithTemplate:
5719 return Visit(QualType(NNS->getAsType(), 0));
5721 llvm_unreachable("Invalid NestedNameSpecifier::Kind!");
5724 /// Check a template argument against its corresponding
5725 /// template type parameter.
5727 /// This routine implements the semantics of C++ [temp.arg.type]. It
5728 /// returns true if an error occurred, and false otherwise.
5729 bool Sema::CheckTemplateArgument(TemplateTypeParmDecl *Param,
5730 TypeSourceInfo *ArgInfo) {
5731 assert(ArgInfo && "invalid TypeSourceInfo");
5732 QualType Arg = ArgInfo->getType();
5733 SourceRange SR = ArgInfo->getTypeLoc().getSourceRange();
5735 if (Arg->isVariablyModifiedType()) {
5736 return Diag(SR.getBegin(), diag::err_variably_modified_template_arg) << Arg;
5737 } else if (Context.hasSameUnqualifiedType(Arg, Context.OverloadTy)) {
5738 return Diag(SR.getBegin(), diag::err_template_arg_overload_type) << SR;
5741 // C++03 [temp.arg.type]p2:
5742 // A local type, a type with no linkage, an unnamed type or a type
5743 // compounded from any of these types shall not be used as a
5744 // template-argument for a template type-parameter.
5746 // C++11 allows these, and even in C++03 we allow them as an extension with
5748 if (LangOpts.CPlusPlus11 || Arg->hasUnnamedOrLocalType()) {
5749 UnnamedLocalNoLinkageFinder Finder(*this, SR);
5750 (void)Finder.Visit(Context.getCanonicalType(Arg));
5756 enum NullPointerValueKind {
5762 /// Determine whether the given template argument is a null pointer
5763 /// value of the appropriate type.
5764 static NullPointerValueKind
5765 isNullPointerValueTemplateArgument(Sema &S, NonTypeTemplateParmDecl *Param,
5766 QualType ParamType, Expr *Arg,
5767 Decl *Entity = nullptr) {
5768 if (Arg->isValueDependent() || Arg->isTypeDependent())
5769 return NPV_NotNullPointer;
5771 // dllimport'd entities aren't constant but are available inside of template
5773 if (Entity && Entity->hasAttr<DLLImportAttr>())
5774 return NPV_NotNullPointer;
5776 if (!S.isCompleteType(Arg->getExprLoc(), ParamType))
5778 "Incomplete parameter type in isNullPointerValueTemplateArgument!");
5780 if (!S.getLangOpts().CPlusPlus11)
5781 return NPV_NotNullPointer;
5783 // Determine whether we have a constant expression.
5784 ExprResult ArgRV = S.DefaultFunctionArrayConversion(Arg);
5785 if (ArgRV.isInvalid())
5789 Expr::EvalResult EvalResult;
5790 SmallVector<PartialDiagnosticAt, 8> Notes;
5791 EvalResult.Diag = &Notes;
5792 if (!Arg->EvaluateAsRValue(EvalResult, S.Context) ||
5793 EvalResult.HasSideEffects) {
5794 SourceLocation DiagLoc = Arg->getExprLoc();
5796 // If our only note is the usual "invalid subexpression" note, just point
5797 // the caret at its location rather than producing an essentially
5799 if (Notes.size() == 1 && Notes[0].second.getDiagID() ==
5800 diag::note_invalid_subexpr_in_const_expr) {
5801 DiagLoc = Notes[0].first;
5805 S.Diag(DiagLoc, diag::err_template_arg_not_address_constant)
5806 << Arg->getType() << Arg->getSourceRange();
5807 for (unsigned I = 0, N = Notes.size(); I != N; ++I)
5808 S.Diag(Notes[I].first, Notes[I].second);
5810 S.Diag(Param->getLocation(), diag::note_template_param_here);
5814 // C++11 [temp.arg.nontype]p1:
5815 // - an address constant expression of type std::nullptr_t
5816 if (Arg->getType()->isNullPtrType())
5817 return NPV_NullPointer;
5819 // - a constant expression that evaluates to a null pointer value (4.10); or
5820 // - a constant expression that evaluates to a null member pointer value
5822 if ((EvalResult.Val.isLValue() && !EvalResult.Val.getLValueBase()) ||
5823 (EvalResult.Val.isMemberPointer() &&
5824 !EvalResult.Val.getMemberPointerDecl())) {
5825 // If our expression has an appropriate type, we've succeeded.
5826 bool ObjCLifetimeConversion;
5827 if (S.Context.hasSameUnqualifiedType(Arg->getType(), ParamType) ||
5828 S.IsQualificationConversion(Arg->getType(), ParamType, false,
5829 ObjCLifetimeConversion))
5830 return NPV_NullPointer;
5832 // The types didn't match, but we know we got a null pointer; complain,
5833 // then recover as if the types were correct.
5834 S.Diag(Arg->getExprLoc(), diag::err_template_arg_wrongtype_null_constant)
5835 << Arg->getType() << ParamType << Arg->getSourceRange();
5836 S.Diag(Param->getLocation(), diag::note_template_param_here);
5837 return NPV_NullPointer;
5840 // If we don't have a null pointer value, but we do have a NULL pointer
5841 // constant, suggest a cast to the appropriate type.
5842 if (Arg->isNullPointerConstant(S.Context, Expr::NPC_NeverValueDependent)) {
5843 std::string Code = "static_cast<" + ParamType.getAsString() + ">(";
5844 S.Diag(Arg->getExprLoc(), diag::err_template_arg_untyped_null_constant)
5845 << ParamType << FixItHint::CreateInsertion(Arg->getBeginLoc(), Code)
5846 << FixItHint::CreateInsertion(S.getLocForEndOfToken(Arg->getEndLoc()),
5848 S.Diag(Param->getLocation(), diag::note_template_param_here);
5849 return NPV_NullPointer;
5852 // FIXME: If we ever want to support general, address-constant expressions
5853 // as non-type template arguments, we should return the ExprResult here to
5854 // be interpreted by the caller.
5855 return NPV_NotNullPointer;
5858 /// Checks whether the given template argument is compatible with its
5859 /// template parameter.
5860 static bool CheckTemplateArgumentIsCompatibleWithParameter(
5861 Sema &S, NonTypeTemplateParmDecl *Param, QualType ParamType, Expr *ArgIn,
5862 Expr *Arg, QualType ArgType) {
5863 bool ObjCLifetimeConversion;
5864 if (ParamType->isPointerType() &&
5865 !ParamType->getAs<PointerType>()->getPointeeType()->isFunctionType() &&
5866 S.IsQualificationConversion(ArgType, ParamType, false,
5867 ObjCLifetimeConversion)) {
5868 // For pointer-to-object types, qualification conversions are
5871 if (const ReferenceType *ParamRef = ParamType->getAs<ReferenceType>()) {
5872 if (!ParamRef->getPointeeType()->isFunctionType()) {
5873 // C++ [temp.arg.nontype]p5b3:
5874 // For a non-type template-parameter of type reference to
5875 // object, no conversions apply. The type referred to by the
5876 // reference may be more cv-qualified than the (otherwise
5877 // identical) type of the template- argument. The
5878 // template-parameter is bound directly to the
5879 // template-argument, which shall be an lvalue.
5881 // FIXME: Other qualifiers?
5882 unsigned ParamQuals = ParamRef->getPointeeType().getCVRQualifiers();
5883 unsigned ArgQuals = ArgType.getCVRQualifiers();
5885 if ((ParamQuals | ArgQuals) != ParamQuals) {
5886 S.Diag(Arg->getBeginLoc(),
5887 diag::err_template_arg_ref_bind_ignores_quals)
5888 << ParamType << Arg->getType() << Arg->getSourceRange();
5889 S.Diag(Param->getLocation(), diag::note_template_param_here);
5895 // At this point, the template argument refers to an object or
5896 // function with external linkage. We now need to check whether the
5897 // argument and parameter types are compatible.
5898 if (!S.Context.hasSameUnqualifiedType(ArgType,
5899 ParamType.getNonReferenceType())) {
5900 // We can't perform this conversion or binding.
5901 if (ParamType->isReferenceType())
5902 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_no_ref_bind)
5903 << ParamType << ArgIn->getType() << Arg->getSourceRange();
5905 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_not_convertible)
5906 << ArgIn->getType() << ParamType << Arg->getSourceRange();
5907 S.Diag(Param->getLocation(), diag::note_template_param_here);
5915 /// Checks whether the given template argument is the address
5916 /// of an object or function according to C++ [temp.arg.nontype]p1.
5918 CheckTemplateArgumentAddressOfObjectOrFunction(Sema &S,
5919 NonTypeTemplateParmDecl *Param,
5922 TemplateArgument &Converted) {
5923 bool Invalid = false;
5925 QualType ArgType = Arg->getType();
5927 bool AddressTaken = false;
5928 SourceLocation AddrOpLoc;
5929 if (S.getLangOpts().MicrosoftExt) {
5930 // Microsoft Visual C++ strips all casts, allows an arbitrary number of
5931 // dereference and address-of operators.
5932 Arg = Arg->IgnoreParenCasts();
5934 bool ExtWarnMSTemplateArg = false;
5935 UnaryOperatorKind FirstOpKind;
5936 SourceLocation FirstOpLoc;
5937 while (UnaryOperator *UnOp = dyn_cast<UnaryOperator>(Arg)) {
5938 UnaryOperatorKind UnOpKind = UnOp->getOpcode();
5939 if (UnOpKind == UO_Deref)
5940 ExtWarnMSTemplateArg = true;
5941 if (UnOpKind == UO_AddrOf || UnOpKind == UO_Deref) {
5942 Arg = UnOp->getSubExpr()->IgnoreParenCasts();
5943 if (!AddrOpLoc.isValid()) {
5944 FirstOpKind = UnOpKind;
5945 FirstOpLoc = UnOp->getOperatorLoc();
5950 if (FirstOpLoc.isValid()) {
5951 if (ExtWarnMSTemplateArg)
5952 S.Diag(ArgIn->getBeginLoc(), diag::ext_ms_deref_template_argument)
5953 << ArgIn->getSourceRange();
5955 if (FirstOpKind == UO_AddrOf)
5956 AddressTaken = true;
5957 else if (Arg->getType()->isPointerType()) {
5958 // We cannot let pointers get dereferenced here, that is obviously not a
5959 // constant expression.
5960 assert(FirstOpKind == UO_Deref);
5961 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_not_decl_ref)
5962 << Arg->getSourceRange();
5966 // See through any implicit casts we added to fix the type.
5967 Arg = Arg->IgnoreImpCasts();
5969 // C++ [temp.arg.nontype]p1:
5971 // A template-argument for a non-type, non-template
5972 // template-parameter shall be one of: [...]
5974 // -- the address of an object or function with external
5975 // linkage, including function templates and function
5976 // template-ids but excluding non-static class members,
5977 // expressed as & id-expression where the & is optional if
5978 // the name refers to a function or array, or if the
5979 // corresponding template-parameter is a reference; or
5981 // In C++98/03 mode, give an extension warning on any extra parentheses.
5982 // See http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#773
5983 bool ExtraParens = false;
5984 while (ParenExpr *Parens = dyn_cast<ParenExpr>(Arg)) {
5985 if (!Invalid && !ExtraParens) {
5986 S.Diag(Arg->getBeginLoc(),
5987 S.getLangOpts().CPlusPlus11
5988 ? diag::warn_cxx98_compat_template_arg_extra_parens
5989 : diag::ext_template_arg_extra_parens)
5990 << Arg->getSourceRange();
5994 Arg = Parens->getSubExpr();
5997 while (SubstNonTypeTemplateParmExpr *subst =
5998 dyn_cast<SubstNonTypeTemplateParmExpr>(Arg))
5999 Arg = subst->getReplacement()->IgnoreImpCasts();
6001 if (UnaryOperator *UnOp = dyn_cast<UnaryOperator>(Arg)) {
6002 if (UnOp->getOpcode() == UO_AddrOf) {
6003 Arg = UnOp->getSubExpr();
6004 AddressTaken = true;
6005 AddrOpLoc = UnOp->getOperatorLoc();
6009 while (SubstNonTypeTemplateParmExpr *subst =
6010 dyn_cast<SubstNonTypeTemplateParmExpr>(Arg))
6011 Arg = subst->getReplacement()->IgnoreImpCasts();
6014 DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Arg);
6015 ValueDecl *Entity = DRE ? DRE->getDecl() : nullptr;
6017 // If our parameter has pointer type, check for a null template value.
6018 if (ParamType->isPointerType() || ParamType->isNullPtrType()) {
6019 switch (isNullPointerValueTemplateArgument(S, Param, ParamType, ArgIn,
6021 case NPV_NullPointer:
6022 S.Diag(Arg->getExprLoc(), diag::warn_cxx98_compat_template_arg_null);
6023 Converted = TemplateArgument(S.Context.getCanonicalType(ParamType),
6024 /*isNullPtr=*/true);
6030 case NPV_NotNullPointer:
6035 // Stop checking the precise nature of the argument if it is value dependent,
6036 // it should be checked when instantiated.
6037 if (Arg->isValueDependent()) {
6038 Converted = TemplateArgument(ArgIn);
6042 if (isa<CXXUuidofExpr>(Arg)) {
6043 if (CheckTemplateArgumentIsCompatibleWithParameter(S, Param, ParamType,
6044 ArgIn, Arg, ArgType))
6047 Converted = TemplateArgument(ArgIn);
6052 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_not_decl_ref)
6053 << Arg->getSourceRange();
6054 S.Diag(Param->getLocation(), diag::note_template_param_here);
6058 // Cannot refer to non-static data members
6059 if (isa<FieldDecl>(Entity) || isa<IndirectFieldDecl>(Entity)) {
6060 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_field)
6061 << Entity << Arg->getSourceRange();
6062 S.Diag(Param->getLocation(), diag::note_template_param_here);
6066 // Cannot refer to non-static member functions
6067 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Entity)) {
6068 if (!Method->isStatic()) {
6069 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_method)
6070 << Method << Arg->getSourceRange();
6071 S.Diag(Param->getLocation(), diag::note_template_param_here);
6076 FunctionDecl *Func = dyn_cast<FunctionDecl>(Entity);
6077 VarDecl *Var = dyn_cast<VarDecl>(Entity);
6079 // A non-type template argument must refer to an object or function.
6080 if (!Func && !Var) {
6081 // We found something, but we don't know specifically what it is.
6082 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_not_object_or_func)
6083 << Arg->getSourceRange();
6084 S.Diag(DRE->getDecl()->getLocation(), diag::note_template_arg_refers_here);
6088 // Address / reference template args must have external linkage in C++98.
6089 if (Entity->getFormalLinkage() == InternalLinkage) {
6090 S.Diag(Arg->getBeginLoc(),
6091 S.getLangOpts().CPlusPlus11
6092 ? diag::warn_cxx98_compat_template_arg_object_internal
6093 : diag::ext_template_arg_object_internal)
6094 << !Func << Entity << Arg->getSourceRange();
6095 S.Diag(Entity->getLocation(), diag::note_template_arg_internal_object)
6097 } else if (!Entity->hasLinkage()) {
6098 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_object_no_linkage)
6099 << !Func << Entity << Arg->getSourceRange();
6100 S.Diag(Entity->getLocation(), diag::note_template_arg_internal_object)
6106 // If the template parameter has pointer type, the function decays.
6107 if (ParamType->isPointerType() && !AddressTaken)
6108 ArgType = S.Context.getPointerType(Func->getType());
6109 else if (AddressTaken && ParamType->isReferenceType()) {
6110 // If we originally had an address-of operator, but the
6111 // parameter has reference type, complain and (if things look
6112 // like they will work) drop the address-of operator.
6113 if (!S.Context.hasSameUnqualifiedType(Func->getType(),
6114 ParamType.getNonReferenceType())) {
6115 S.Diag(AddrOpLoc, diag::err_template_arg_address_of_non_pointer)
6117 S.Diag(Param->getLocation(), diag::note_template_param_here);
6121 S.Diag(AddrOpLoc, diag::err_template_arg_address_of_non_pointer)
6123 << FixItHint::CreateRemoval(AddrOpLoc);
6124 S.Diag(Param->getLocation(), diag::note_template_param_here);
6126 ArgType = Func->getType();
6129 // A value of reference type is not an object.
6130 if (Var->getType()->isReferenceType()) {
6131 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_reference_var)
6132 << Var->getType() << Arg->getSourceRange();
6133 S.Diag(Param->getLocation(), diag::note_template_param_here);
6137 // A template argument must have static storage duration.
6138 if (Var->getTLSKind()) {
6139 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_thread_local)
6140 << Arg->getSourceRange();
6141 S.Diag(Var->getLocation(), diag::note_template_arg_refers_here);
6145 // If the template parameter has pointer type, we must have taken
6146 // the address of this object.
6147 if (ParamType->isReferenceType()) {
6149 // If we originally had an address-of operator, but the
6150 // parameter has reference type, complain and (if things look
6151 // like they will work) drop the address-of operator.
6152 if (!S.Context.hasSameUnqualifiedType(Var->getType(),
6153 ParamType.getNonReferenceType())) {
6154 S.Diag(AddrOpLoc, diag::err_template_arg_address_of_non_pointer)
6156 S.Diag(Param->getLocation(), diag::note_template_param_here);
6160 S.Diag(AddrOpLoc, diag::err_template_arg_address_of_non_pointer)
6162 << FixItHint::CreateRemoval(AddrOpLoc);
6163 S.Diag(Param->getLocation(), diag::note_template_param_here);
6165 ArgType = Var->getType();
6167 } else if (!AddressTaken && ParamType->isPointerType()) {
6168 if (Var->getType()->isArrayType()) {
6169 // Array-to-pointer decay.
6170 ArgType = S.Context.getArrayDecayedType(Var->getType());
6172 // If the template parameter has pointer type but the address of
6173 // this object was not taken, complain and (possibly) recover by
6174 // taking the address of the entity.
6175 ArgType = S.Context.getPointerType(Var->getType());
6176 if (!S.Context.hasSameUnqualifiedType(ArgType, ParamType)) {
6177 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_not_address_of)
6179 S.Diag(Param->getLocation(), diag::note_template_param_here);
6183 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_not_address_of)
6184 << ParamType << FixItHint::CreateInsertion(Arg->getBeginLoc(), "&");
6186 S.Diag(Param->getLocation(), diag::note_template_param_here);
6191 if (CheckTemplateArgumentIsCompatibleWithParameter(S, Param, ParamType, ArgIn,
6195 // Create the template argument.
6197 TemplateArgument(cast<ValueDecl>(Entity->getCanonicalDecl()), ParamType);
6198 S.MarkAnyDeclReferenced(Arg->getBeginLoc(), Entity, false);
6202 /// Checks whether the given template argument is a pointer to
6203 /// member constant according to C++ [temp.arg.nontype]p1.
6204 static bool CheckTemplateArgumentPointerToMember(Sema &S,
6205 NonTypeTemplateParmDecl *Param,
6208 TemplateArgument &Converted) {
6209 bool Invalid = false;
6211 Expr *Arg = ResultArg;
6212 bool ObjCLifetimeConversion;
6214 // C++ [temp.arg.nontype]p1:
6216 // A template-argument for a non-type, non-template
6217 // template-parameter shall be one of: [...]
6219 // -- a pointer to member expressed as described in 5.3.1.
6220 DeclRefExpr *DRE = nullptr;
6222 // In C++98/03 mode, give an extension warning on any extra parentheses.
6223 // See http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#773
6224 bool ExtraParens = false;
6225 while (ParenExpr *Parens = dyn_cast<ParenExpr>(Arg)) {
6226 if (!Invalid && !ExtraParens) {
6227 S.Diag(Arg->getBeginLoc(),
6228 S.getLangOpts().CPlusPlus11
6229 ? diag::warn_cxx98_compat_template_arg_extra_parens
6230 : diag::ext_template_arg_extra_parens)
6231 << Arg->getSourceRange();
6235 Arg = Parens->getSubExpr();
6238 while (SubstNonTypeTemplateParmExpr *subst =
6239 dyn_cast<SubstNonTypeTemplateParmExpr>(Arg))
6240 Arg = subst->getReplacement()->IgnoreImpCasts();
6242 // A pointer-to-member constant written &Class::member.
6243 if (UnaryOperator *UnOp = dyn_cast<UnaryOperator>(Arg)) {
6244 if (UnOp->getOpcode() == UO_AddrOf) {
6245 DRE = dyn_cast<DeclRefExpr>(UnOp->getSubExpr());
6246 if (DRE && !DRE->getQualifier())
6250 // A constant of pointer-to-member type.
6251 else if ((DRE = dyn_cast<DeclRefExpr>(Arg))) {
6252 ValueDecl *VD = DRE->getDecl();
6253 if (VD->getType()->isMemberPointerType()) {
6254 if (isa<NonTypeTemplateParmDecl>(VD)) {
6255 if (Arg->isTypeDependent() || Arg->isValueDependent()) {
6256 Converted = TemplateArgument(Arg);
6258 VD = cast<ValueDecl>(VD->getCanonicalDecl());
6259 Converted = TemplateArgument(VD, ParamType);
6268 ValueDecl *Entity = DRE ? DRE->getDecl() : nullptr;
6270 // Check for a null pointer value.
6271 switch (isNullPointerValueTemplateArgument(S, Param, ParamType, ResultArg,
6275 case NPV_NullPointer:
6276 S.Diag(ResultArg->getExprLoc(), diag::warn_cxx98_compat_template_arg_null);
6277 Converted = TemplateArgument(S.Context.getCanonicalType(ParamType),
6280 case NPV_NotNullPointer:
6284 if (S.IsQualificationConversion(ResultArg->getType(),
6285 ParamType.getNonReferenceType(), false,
6286 ObjCLifetimeConversion)) {
6287 ResultArg = S.ImpCastExprToType(ResultArg, ParamType, CK_NoOp,
6288 ResultArg->getValueKind())
6290 } else if (!S.Context.hasSameUnqualifiedType(
6291 ResultArg->getType(), ParamType.getNonReferenceType())) {
6292 // We can't perform this conversion.
6293 S.Diag(ResultArg->getBeginLoc(), diag::err_template_arg_not_convertible)
6294 << ResultArg->getType() << ParamType << ResultArg->getSourceRange();
6295 S.Diag(Param->getLocation(), diag::note_template_param_here);
6300 return S.Diag(Arg->getBeginLoc(),
6301 diag::err_template_arg_not_pointer_to_member_form)
6302 << Arg->getSourceRange();
6304 if (isa<FieldDecl>(DRE->getDecl()) ||
6305 isa<IndirectFieldDecl>(DRE->getDecl()) ||
6306 isa<CXXMethodDecl>(DRE->getDecl())) {
6307 assert((isa<FieldDecl>(DRE->getDecl()) ||
6308 isa<IndirectFieldDecl>(DRE->getDecl()) ||
6309 !cast<CXXMethodDecl>(DRE->getDecl())->isStatic()) &&
6310 "Only non-static member pointers can make it here");
6312 // Okay: this is the address of a non-static member, and therefore
6313 // a member pointer constant.
6314 if (Arg->isTypeDependent() || Arg->isValueDependent()) {
6315 Converted = TemplateArgument(Arg);
6317 ValueDecl *D = cast<ValueDecl>(DRE->getDecl()->getCanonicalDecl());
6318 Converted = TemplateArgument(D, ParamType);
6323 // We found something else, but we don't know specifically what it is.
6324 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_not_pointer_to_member_form)
6325 << Arg->getSourceRange();
6326 S.Diag(DRE->getDecl()->getLocation(), diag::note_template_arg_refers_here);
6330 /// Check a template argument against its corresponding
6331 /// non-type template parameter.
6333 /// This routine implements the semantics of C++ [temp.arg.nontype].
6334 /// If an error occurred, it returns ExprError(); otherwise, it
6335 /// returns the converted template argument. \p ParamType is the
6336 /// type of the non-type template parameter after it has been instantiated.
6337 ExprResult Sema::CheckTemplateArgument(NonTypeTemplateParmDecl *Param,
6338 QualType ParamType, Expr *Arg,
6339 TemplateArgument &Converted,
6340 CheckTemplateArgumentKind CTAK) {
6341 SourceLocation StartLoc = Arg->getBeginLoc();
6343 // If the parameter type somehow involves auto, deduce the type now.
6344 if (getLangOpts().CPlusPlus17 && ParamType->isUndeducedType()) {
6345 // During template argument deduction, we allow 'decltype(auto)' to
6346 // match an arbitrary dependent argument.
6347 // FIXME: The language rules don't say what happens in this case.
6348 // FIXME: We get an opaque dependent type out of decltype(auto) if the
6349 // expression is merely instantiation-dependent; is this enough?
6350 if (CTAK == CTAK_Deduced && Arg->isTypeDependent()) {
6351 auto *AT = dyn_cast<AutoType>(ParamType);
6352 if (AT && AT->isDecltypeAuto()) {
6353 Converted = TemplateArgument(Arg);
6358 // When checking a deduced template argument, deduce from its type even if
6359 // the type is dependent, in order to check the types of non-type template
6360 // arguments line up properly in partial ordering.
6361 Optional<unsigned> Depth = Param->getDepth() + 1;
6362 Expr *DeductionArg = Arg;
6363 if (auto *PE = dyn_cast<PackExpansionExpr>(DeductionArg))
6364 DeductionArg = PE->getPattern();
6366 Context.getTrivialTypeSourceInfo(ParamType, Param->getLocation()),
6367 DeductionArg, ParamType, Depth) == DAR_Failed) {
6368 Diag(Arg->getExprLoc(),
6369 diag::err_non_type_template_parm_type_deduction_failure)
6370 << Param->getDeclName() << Param->getType() << Arg->getType()
6371 << Arg->getSourceRange();
6372 Diag(Param->getLocation(), diag::note_template_param_here);
6375 // CheckNonTypeTemplateParameterType will produce a diagnostic if there's
6376 // an error. The error message normally references the parameter
6377 // declaration, but here we'll pass the argument location because that's
6378 // where the parameter type is deduced.
6379 ParamType = CheckNonTypeTemplateParameterType(ParamType, Arg->getExprLoc());
6380 if (ParamType.isNull()) {
6381 Diag(Param->getLocation(), diag::note_template_param_here);
6386 // We should have already dropped all cv-qualifiers by now.
6387 assert(!ParamType.hasQualifiers() &&
6388 "non-type template parameter type cannot be qualified");
6390 if (CTAK == CTAK_Deduced &&
6391 !Context.hasSameType(ParamType.getNonLValueExprType(Context),
6393 // FIXME: If either type is dependent, we skip the check. This isn't
6394 // correct, since during deduction we're supposed to have replaced each
6395 // template parameter with some unique (non-dependent) placeholder.
6396 // FIXME: If the argument type contains 'auto', we carry on and fail the
6397 // type check in order to force specific types to be more specialized than
6398 // 'auto'. It's not clear how partial ordering with 'auto' is supposed to
6400 if ((ParamType->isDependentType() || Arg->isTypeDependent()) &&
6401 !Arg->getType()->getContainedAutoType()) {
6402 Converted = TemplateArgument(Arg);
6405 // FIXME: This attempts to implement C++ [temp.deduct.type]p17. Per DR1770,
6406 // we should actually be checking the type of the template argument in P,
6407 // not the type of the template argument deduced from A, against the
6408 // template parameter type.
6409 Diag(StartLoc, diag::err_deduced_non_type_template_arg_type_mismatch)
6411 << ParamType.getUnqualifiedType();
6412 Diag(Param->getLocation(), diag::note_template_param_here);
6416 // If either the parameter has a dependent type or the argument is
6417 // type-dependent, there's nothing we can check now.
6418 if (ParamType->isDependentType() || Arg->isTypeDependent()) {
6419 // Force the argument to the type of the parameter to maintain invariants.
6420 auto *PE = dyn_cast<PackExpansionExpr>(Arg);
6422 Arg = PE->getPattern();
6423 ExprResult E = ImpCastExprToType(
6424 Arg, ParamType.getNonLValueExprType(Context), CK_Dependent,
6425 ParamType->isLValueReferenceType() ? VK_LValue :
6426 ParamType->isRValueReferenceType() ? VK_XValue : VK_RValue);
6430 // Recreate a pack expansion if we unwrapped one.
6432 PackExpansionExpr(E.get()->getType(), E.get(), PE->getEllipsisLoc(),
6433 PE->getNumExpansions());
6435 Converted = TemplateArgument(E.get());
6439 // The initialization of the parameter from the argument is
6440 // a constant-evaluated context.
6441 EnterExpressionEvaluationContext ConstantEvaluated(
6442 *this, Sema::ExpressionEvaluationContext::ConstantEvaluated);
6444 if (getLangOpts().CPlusPlus17) {
6445 // C++17 [temp.arg.nontype]p1:
6446 // A template-argument for a non-type template parameter shall be
6447 // a converted constant expression of the type of the template-parameter.
6449 ExprResult ArgResult = CheckConvertedConstantExpression(
6450 Arg, ParamType, Value, CCEK_TemplateArg);
6451 if (ArgResult.isInvalid())
6454 // For a value-dependent argument, CheckConvertedConstantExpression is
6455 // permitted (and expected) to be unable to determine a value.
6456 if (ArgResult.get()->isValueDependent()) {
6457 Converted = TemplateArgument(ArgResult.get());
6461 QualType CanonParamType = Context.getCanonicalType(ParamType);
6463 // Convert the APValue to a TemplateArgument.
6464 switch (Value.getKind()) {
6466 assert(ParamType->isNullPtrType());
6467 Converted = TemplateArgument(CanonParamType, /*isNullPtr*/true);
6469 case APValue::Indeterminate:
6470 llvm_unreachable("result of constant evaluation should be initialized");
6473 assert(ParamType->isIntegralOrEnumerationType());
6474 Converted = TemplateArgument(Context, Value.getInt(), CanonParamType);
6476 case APValue::MemberPointer: {
6477 assert(ParamType->isMemberPointerType());
6479 // FIXME: We need TemplateArgument representation and mangling for these.
6480 if (!Value.getMemberPointerPath().empty()) {
6481 Diag(Arg->getBeginLoc(),
6482 diag::err_template_arg_member_ptr_base_derived_not_supported)
6483 << Value.getMemberPointerDecl() << ParamType
6484 << Arg->getSourceRange();
6488 auto *VD = const_cast<ValueDecl*>(Value.getMemberPointerDecl());
6489 Converted = VD ? TemplateArgument(VD, CanonParamType)
6490 : TemplateArgument(CanonParamType, /*isNullPtr*/true);
6493 case APValue::LValue: {
6494 // For a non-type template-parameter of pointer or reference type,
6495 // the value of the constant expression shall not refer to
6496 assert(ParamType->isPointerType() || ParamType->isReferenceType() ||
6497 ParamType->isNullPtrType());
6498 // -- a temporary object
6499 // -- a string literal
6500 // -- the result of a typeid expression, or
6501 // -- a predefined __func__ variable
6502 APValue::LValueBase Base = Value.getLValueBase();
6503 auto *VD = const_cast<ValueDecl *>(Base.dyn_cast<const ValueDecl *>());
6505 auto *E = Base.dyn_cast<const Expr *>();
6506 if (E && isa<CXXUuidofExpr>(E)) {
6507 Converted = TemplateArgument(ArgResult.get()->IgnoreImpCasts());
6510 Diag(Arg->getBeginLoc(), diag::err_template_arg_not_decl_ref)
6511 << Arg->getSourceRange();
6515 if (Value.hasLValuePath() && Value.getLValuePath().size() == 1 &&
6516 VD && VD->getType()->isArrayType() &&
6517 Value.getLValuePath()[0].getAsArrayIndex() == 0 &&
6518 !Value.isLValueOnePastTheEnd() && ParamType->isPointerType()) {
6519 // Per defect report (no number yet):
6520 // ... other than a pointer to the first element of a complete array
6522 } else if (!Value.hasLValuePath() || Value.getLValuePath().size() ||
6523 Value.isLValueOnePastTheEnd()) {
6524 Diag(StartLoc, diag::err_non_type_template_arg_subobject)
6525 << Value.getAsString(Context, ParamType);
6528 assert((VD || !ParamType->isReferenceType()) &&
6529 "null reference should not be a constant expression");
6530 assert((!VD || !ParamType->isNullPtrType()) &&
6531 "non-null value of type nullptr_t?");
6532 Converted = VD ? TemplateArgument(VD, CanonParamType)
6533 : TemplateArgument(CanonParamType, /*isNullPtr*/true);
6536 case APValue::AddrLabelDiff:
6537 return Diag(StartLoc, diag::err_non_type_template_arg_addr_label_diff);
6538 case APValue::FixedPoint:
6539 case APValue::Float:
6540 case APValue::ComplexInt:
6541 case APValue::ComplexFloat:
6542 case APValue::Vector:
6543 case APValue::Array:
6544 case APValue::Struct:
6545 case APValue::Union:
6546 llvm_unreachable("invalid kind for template argument");
6549 return ArgResult.get();
6552 // C++ [temp.arg.nontype]p5:
6553 // The following conversions are performed on each expression used
6554 // as a non-type template-argument. If a non-type
6555 // template-argument cannot be converted to the type of the
6556 // corresponding template-parameter then the program is
6558 if (ParamType->isIntegralOrEnumerationType()) {
6560 // -- for a non-type template-parameter of integral or
6561 // enumeration type, conversions permitted in a converted
6562 // constant expression are applied.
6565 // -- for a non-type template-parameter of integral or
6566 // enumeration type, integral promotions (4.5) and integral
6567 // conversions (4.7) are applied.
6569 if (getLangOpts().CPlusPlus11) {
6570 // C++ [temp.arg.nontype]p1:
6571 // A template-argument for a non-type, non-template template-parameter
6574 // -- for a non-type template-parameter of integral or enumeration
6575 // type, a converted constant expression of the type of the
6576 // template-parameter; or
6578 ExprResult ArgResult =
6579 CheckConvertedConstantExpression(Arg, ParamType, Value,
6581 if (ArgResult.isInvalid())
6584 // We can't check arbitrary value-dependent arguments.
6585 if (ArgResult.get()->isValueDependent()) {
6586 Converted = TemplateArgument(ArgResult.get());
6590 // Widen the argument value to sizeof(parameter type). This is almost
6591 // always a no-op, except when the parameter type is bool. In
6592 // that case, this may extend the argument from 1 bit to 8 bits.
6593 QualType IntegerType = ParamType;
6594 if (const EnumType *Enum = IntegerType->getAs<EnumType>())
6595 IntegerType = Enum->getDecl()->getIntegerType();
6596 Value = Value.extOrTrunc(Context.getTypeSize(IntegerType));
6598 Converted = TemplateArgument(Context, Value,
6599 Context.getCanonicalType(ParamType));
6603 ExprResult ArgResult = DefaultLvalueConversion(Arg);
6604 if (ArgResult.isInvalid())
6606 Arg = ArgResult.get();
6608 QualType ArgType = Arg->getType();
6610 // C++ [temp.arg.nontype]p1:
6611 // A template-argument for a non-type, non-template
6612 // template-parameter shall be one of:
6614 // -- an integral constant-expression of integral or enumeration
6616 // -- the name of a non-type template-parameter; or
6618 if (!ArgType->isIntegralOrEnumerationType()) {
6619 Diag(Arg->getBeginLoc(), diag::err_template_arg_not_integral_or_enumeral)
6620 << ArgType << Arg->getSourceRange();
6621 Diag(Param->getLocation(), diag::note_template_param_here);
6623 } else if (!Arg->isValueDependent()) {
6624 class TmplArgICEDiagnoser : public VerifyICEDiagnoser {
6628 TmplArgICEDiagnoser(QualType T) : T(T) { }
6630 void diagnoseNotICE(Sema &S, SourceLocation Loc,
6631 SourceRange SR) override {
6632 S.Diag(Loc, diag::err_template_arg_not_ice) << T << SR;
6634 } Diagnoser(ArgType);
6636 Arg = VerifyIntegerConstantExpression(Arg, &Value, Diagnoser,
6642 // From here on out, all we care about is the unqualified form
6643 // of the argument type.
6644 ArgType = ArgType.getUnqualifiedType();
6646 // Try to convert the argument to the parameter's type.
6647 if (Context.hasSameType(ParamType, ArgType)) {
6648 // Okay: no conversion necessary
6649 } else if (ParamType->isBooleanType()) {
6650 // This is an integral-to-boolean conversion.
6651 Arg = ImpCastExprToType(Arg, ParamType, CK_IntegralToBoolean).get();
6652 } else if (IsIntegralPromotion(Arg, ArgType, ParamType) ||
6653 !ParamType->isEnumeralType()) {
6654 // This is an integral promotion or conversion.
6655 Arg = ImpCastExprToType(Arg, ParamType, CK_IntegralCast).get();
6657 // We can't perform this conversion.
6658 Diag(Arg->getBeginLoc(), diag::err_template_arg_not_convertible)
6659 << Arg->getType() << ParamType << Arg->getSourceRange();
6660 Diag(Param->getLocation(), diag::note_template_param_here);
6664 // Add the value of this argument to the list of converted
6665 // arguments. We use the bitwidth and signedness of the template
6667 if (Arg->isValueDependent()) {
6668 // The argument is value-dependent. Create a new
6669 // TemplateArgument with the converted expression.
6670 Converted = TemplateArgument(Arg);
6674 QualType IntegerType = Context.getCanonicalType(ParamType);
6675 if (const EnumType *Enum = IntegerType->getAs<EnumType>())
6676 IntegerType = Context.getCanonicalType(Enum->getDecl()->getIntegerType());
6678 if (ParamType->isBooleanType()) {
6679 // Value must be zero or one.
6681 unsigned AllowedBits = Context.getTypeSize(IntegerType);
6682 if (Value.getBitWidth() != AllowedBits)
6683 Value = Value.extOrTrunc(AllowedBits);
6684 Value.setIsSigned(IntegerType->isSignedIntegerOrEnumerationType());
6686 llvm::APSInt OldValue = Value;
6688 // Coerce the template argument's value to the value it will have
6689 // based on the template parameter's type.
6690 unsigned AllowedBits = Context.getTypeSize(IntegerType);
6691 if (Value.getBitWidth() != AllowedBits)
6692 Value = Value.extOrTrunc(AllowedBits);
6693 Value.setIsSigned(IntegerType->isSignedIntegerOrEnumerationType());
6695 // Complain if an unsigned parameter received a negative value.
6696 if (IntegerType->isUnsignedIntegerOrEnumerationType()
6697 && (OldValue.isSigned() && OldValue.isNegative())) {
6698 Diag(Arg->getBeginLoc(), diag::warn_template_arg_negative)
6699 << OldValue.toString(10) << Value.toString(10) << Param->getType()
6700 << Arg->getSourceRange();
6701 Diag(Param->getLocation(), diag::note_template_param_here);
6704 // Complain if we overflowed the template parameter's type.
6705 unsigned RequiredBits;
6706 if (IntegerType->isUnsignedIntegerOrEnumerationType())
6707 RequiredBits = OldValue.getActiveBits();
6708 else if (OldValue.isUnsigned())
6709 RequiredBits = OldValue.getActiveBits() + 1;
6711 RequiredBits = OldValue.getMinSignedBits();
6712 if (RequiredBits > AllowedBits) {
6713 Diag(Arg->getBeginLoc(), diag::warn_template_arg_too_large)
6714 << OldValue.toString(10) << Value.toString(10) << Param->getType()
6715 << Arg->getSourceRange();
6716 Diag(Param->getLocation(), diag::note_template_param_here);
6720 Converted = TemplateArgument(Context, Value,
6721 ParamType->isEnumeralType()
6722 ? Context.getCanonicalType(ParamType)
6727 QualType ArgType = Arg->getType();
6728 DeclAccessPair FoundResult; // temporary for ResolveOverloadedFunction
6730 // Handle pointer-to-function, reference-to-function, and
6731 // pointer-to-member-function all in (roughly) the same way.
6732 if (// -- For a non-type template-parameter of type pointer to
6733 // function, only the function-to-pointer conversion (4.3) is
6734 // applied. If the template-argument represents a set of
6735 // overloaded functions (or a pointer to such), the matching
6736 // function is selected from the set (13.4).
6737 (ParamType->isPointerType() &&
6738 ParamType->getAs<PointerType>()->getPointeeType()->isFunctionType()) ||
6739 // -- For a non-type template-parameter of type reference to
6740 // function, no conversions apply. If the template-argument
6741 // represents a set of overloaded functions, the matching
6742 // function is selected from the set (13.4).
6743 (ParamType->isReferenceType() &&
6744 ParamType->getAs<ReferenceType>()->getPointeeType()->isFunctionType()) ||
6745 // -- For a non-type template-parameter of type pointer to
6746 // member function, no conversions apply. If the
6747 // template-argument represents a set of overloaded member
6748 // functions, the matching member function is selected from
6750 (ParamType->isMemberPointerType() &&
6751 ParamType->getAs<MemberPointerType>()->getPointeeType()
6752 ->isFunctionType())) {
6754 if (Arg->getType() == Context.OverloadTy) {
6755 if (FunctionDecl *Fn = ResolveAddressOfOverloadedFunction(Arg, ParamType,
6758 if (DiagnoseUseOfDecl(Fn, Arg->getBeginLoc()))
6761 Arg = FixOverloadedFunctionReference(Arg, FoundResult, Fn);
6762 ArgType = Arg->getType();
6767 if (!ParamType->isMemberPointerType()) {
6768 if (CheckTemplateArgumentAddressOfObjectOrFunction(*this, Param,
6775 if (CheckTemplateArgumentPointerToMember(*this, Param, ParamType, Arg,
6781 if (ParamType->isPointerType()) {
6782 // -- for a non-type template-parameter of type pointer to
6783 // object, qualification conversions (4.4) and the
6784 // array-to-pointer conversion (4.2) are applied.
6785 // C++0x also allows a value of std::nullptr_t.
6786 assert(ParamType->getPointeeType()->isIncompleteOrObjectType() &&
6787 "Only object pointers allowed here");
6789 if (CheckTemplateArgumentAddressOfObjectOrFunction(*this, Param,
6796 if (const ReferenceType *ParamRefType = ParamType->getAs<ReferenceType>()) {
6797 // -- For a non-type template-parameter of type reference to
6798 // object, no conversions apply. The type referred to by the
6799 // reference may be more cv-qualified than the (otherwise
6800 // identical) type of the template-argument. The
6801 // template-parameter is bound directly to the
6802 // template-argument, which must be an lvalue.
6803 assert(ParamRefType->getPointeeType()->isIncompleteOrObjectType() &&
6804 "Only object references allowed here");
6806 if (Arg->getType() == Context.OverloadTy) {
6807 if (FunctionDecl *Fn = ResolveAddressOfOverloadedFunction(Arg,
6808 ParamRefType->getPointeeType(),
6811 if (DiagnoseUseOfDecl(Fn, Arg->getBeginLoc()))
6814 Arg = FixOverloadedFunctionReference(Arg, FoundResult, Fn);
6815 ArgType = Arg->getType();
6820 if (CheckTemplateArgumentAddressOfObjectOrFunction(*this, Param,
6827 // Deal with parameters of type std::nullptr_t.
6828 if (ParamType->isNullPtrType()) {
6829 if (Arg->isTypeDependent() || Arg->isValueDependent()) {
6830 Converted = TemplateArgument(Arg);
6834 switch (isNullPointerValueTemplateArgument(*this, Param, ParamType, Arg)) {
6835 case NPV_NotNullPointer:
6836 Diag(Arg->getExprLoc(), diag::err_template_arg_not_convertible)
6837 << Arg->getType() << ParamType;
6838 Diag(Param->getLocation(), diag::note_template_param_here);
6844 case NPV_NullPointer:
6845 Diag(Arg->getExprLoc(), diag::warn_cxx98_compat_template_arg_null);
6846 Converted = TemplateArgument(Context.getCanonicalType(ParamType),
6852 // -- For a non-type template-parameter of type pointer to data
6853 // member, qualification conversions (4.4) are applied.
6854 assert(ParamType->isMemberPointerType() && "Only pointers to members remain");
6856 if (CheckTemplateArgumentPointerToMember(*this, Param, ParamType, Arg,
6862 static void DiagnoseTemplateParameterListArityMismatch(
6863 Sema &S, TemplateParameterList *New, TemplateParameterList *Old,
6864 Sema::TemplateParameterListEqualKind Kind, SourceLocation TemplateArgLoc);
6866 /// Check a template argument against its corresponding
6867 /// template template parameter.
6869 /// This routine implements the semantics of C++ [temp.arg.template].
6870 /// It returns true if an error occurred, and false otherwise.
6871 bool Sema::CheckTemplateTemplateArgument(TemplateParameterList *Params,
6872 TemplateArgumentLoc &Arg) {
6873 TemplateName Name = Arg.getArgument().getAsTemplateOrTemplatePattern();
6874 TemplateDecl *Template = Name.getAsTemplateDecl();
6876 // Any dependent template name is fine.
6877 assert(Name.isDependent() && "Non-dependent template isn't a declaration?");
6881 if (Template->isInvalidDecl())
6884 // C++0x [temp.arg.template]p1:
6885 // A template-argument for a template template-parameter shall be
6886 // the name of a class template or an alias template, expressed as an
6887 // id-expression. When the template-argument names a class template, only
6888 // primary class templates are considered when matching the
6889 // template template argument with the corresponding parameter;
6890 // partial specializations are not considered even if their
6891 // parameter lists match that of the template template parameter.
6893 // Note that we also allow template template parameters here, which
6894 // will happen when we are dealing with, e.g., class template
6895 // partial specializations.
6896 if (!isa<ClassTemplateDecl>(Template) &&
6897 !isa<TemplateTemplateParmDecl>(Template) &&
6898 !isa<TypeAliasTemplateDecl>(Template) &&
6899 !isa<BuiltinTemplateDecl>(Template)) {
6900 assert(isa<FunctionTemplateDecl>(Template) &&
6901 "Only function templates are possible here");
6902 Diag(Arg.getLocation(), diag::err_template_arg_not_valid_template);
6903 Diag(Template->getLocation(), diag::note_template_arg_refers_here_func)
6907 // C++1z [temp.arg.template]p3: (DR 150)
6908 // A template-argument matches a template template-parameter P when P
6909 // is at least as specialized as the template-argument A.
6910 if (getLangOpts().RelaxedTemplateTemplateArgs) {
6911 // Quick check for the common case:
6912 // If P contains a parameter pack, then A [...] matches P if each of A's
6913 // template parameters matches the corresponding template parameter in
6914 // the template-parameter-list of P.
6915 if (TemplateParameterListsAreEqual(
6916 Template->getTemplateParameters(), Params, false,
6917 TPL_TemplateTemplateArgumentMatch, Arg.getLocation()))
6920 if (isTemplateTemplateParameterAtLeastAsSpecializedAs(Params, Template,
6923 // FIXME: Produce better diagnostics for deduction failures.
6926 return !TemplateParameterListsAreEqual(Template->getTemplateParameters(),
6929 TPL_TemplateTemplateArgumentMatch,
6933 /// Given a non-type template argument that refers to a
6934 /// declaration and the type of its corresponding non-type template
6935 /// parameter, produce an expression that properly refers to that
6938 Sema::BuildExpressionFromDeclTemplateArgument(const TemplateArgument &Arg,
6940 SourceLocation Loc) {
6941 // C++ [temp.param]p8:
6943 // A non-type template-parameter of type "array of T" or
6944 // "function returning T" is adjusted to be of type "pointer to
6945 // T" or "pointer to function returning T", respectively.
6946 if (ParamType->isArrayType())
6947 ParamType = Context.getArrayDecayedType(ParamType);
6948 else if (ParamType->isFunctionType())
6949 ParamType = Context.getPointerType(ParamType);
6951 // For a NULL non-type template argument, return nullptr casted to the
6952 // parameter's type.
6953 if (Arg.getKind() == TemplateArgument::NullPtr) {
6954 return ImpCastExprToType(
6955 new (Context) CXXNullPtrLiteralExpr(Context.NullPtrTy, Loc),
6957 ParamType->getAs<MemberPointerType>()
6958 ? CK_NullToMemberPointer
6959 : CK_NullToPointer);
6961 assert(Arg.getKind() == TemplateArgument::Declaration &&
6962 "Only declaration template arguments permitted here");
6964 ValueDecl *VD = Arg.getAsDecl();
6966 if (VD->getDeclContext()->isRecord() &&
6967 (isa<CXXMethodDecl>(VD) || isa<FieldDecl>(VD) ||
6968 isa<IndirectFieldDecl>(VD))) {
6969 // If the value is a class member, we might have a pointer-to-member.
6970 // Determine whether the non-type template template parameter is of
6971 // pointer-to-member type. If so, we need to build an appropriate
6972 // expression for a pointer-to-member, since a "normal" DeclRefExpr
6973 // would refer to the member itself.
6974 if (ParamType->isMemberPointerType()) {
6976 = Context.getTypeDeclType(cast<RecordDecl>(VD->getDeclContext()));
6977 NestedNameSpecifier *Qualifier
6978 = NestedNameSpecifier::Create(Context, nullptr, false,
6979 ClassType.getTypePtr());
6981 SS.MakeTrivial(Context, Qualifier, Loc);
6983 // The actual value-ness of this is unimportant, but for
6984 // internal consistency's sake, references to instance methods
6986 ExprValueKind VK = VK_LValue;
6987 if (isa<CXXMethodDecl>(VD) && cast<CXXMethodDecl>(VD)->isInstance())
6990 ExprResult RefExpr = BuildDeclRefExpr(VD,
6991 VD->getType().getNonReferenceType(),
6995 if (RefExpr.isInvalid())
6998 RefExpr = CreateBuiltinUnaryOp(Loc, UO_AddrOf, RefExpr.get());
7000 // We might need to perform a trailing qualification conversion, since
7001 // the element type on the parameter could be more qualified than the
7002 // element type in the expression we constructed.
7003 bool ObjCLifetimeConversion;
7004 if (IsQualificationConversion(((Expr*) RefExpr.get())->getType(),
7005 ParamType.getUnqualifiedType(), false,
7006 ObjCLifetimeConversion))
7007 RefExpr = ImpCastExprToType(RefExpr.get(), ParamType.getUnqualifiedType(), CK_NoOp);
7009 assert(!RefExpr.isInvalid() &&
7010 Context.hasSameType(((Expr*) RefExpr.get())->getType(),
7011 ParamType.getUnqualifiedType()));
7016 QualType T = VD->getType().getNonReferenceType();
7018 if (ParamType->isPointerType()) {
7019 // When the non-type template parameter is a pointer, take the
7020 // address of the declaration.
7021 ExprResult RefExpr = BuildDeclRefExpr(VD, T, VK_LValue, Loc);
7022 if (RefExpr.isInvalid())
7025 if (!Context.hasSameUnqualifiedType(ParamType->getPointeeType(), T) &&
7026 (T->isFunctionType() || T->isArrayType())) {
7027 // Decay functions and arrays unless we're forming a pointer to array.
7028 RefExpr = DefaultFunctionArrayConversion(RefExpr.get());
7029 if (RefExpr.isInvalid())
7035 // Take the address of everything else
7036 return CreateBuiltinUnaryOp(Loc, UO_AddrOf, RefExpr.get());
7039 ExprValueKind VK = VK_RValue;
7041 // If the non-type template parameter has reference type, qualify the
7042 // resulting declaration reference with the extra qualifiers on the
7043 // type that the reference refers to.
7044 if (const ReferenceType *TargetRef = ParamType->getAs<ReferenceType>()) {
7046 T = Context.getQualifiedType(T,
7047 TargetRef->getPointeeType().getQualifiers());
7048 } else if (isa<FunctionDecl>(VD)) {
7049 // References to functions are always lvalues.
7053 return BuildDeclRefExpr(VD, T, VK, Loc);
7056 /// Construct a new expression that refers to the given
7057 /// integral template argument with the given source-location
7060 /// This routine takes care of the mapping from an integral template
7061 /// argument (which may have any integral type) to the appropriate
7064 Sema::BuildExpressionFromIntegralTemplateArgument(const TemplateArgument &Arg,
7065 SourceLocation Loc) {
7066 assert(Arg.getKind() == TemplateArgument::Integral &&
7067 "Operation is only valid for integral template arguments");
7068 QualType OrigT = Arg.getIntegralType();
7070 // If this is an enum type that we're instantiating, we need to use an integer
7071 // type the same size as the enumerator. We don't want to build an
7072 // IntegerLiteral with enum type. The integer type of an enum type can be of
7073 // any integral type with C++11 enum classes, make sure we create the right
7074 // type of literal for it.
7076 if (const EnumType *ET = OrigT->getAs<EnumType>())
7077 T = ET->getDecl()->getIntegerType();
7080 if (T->isAnyCharacterType()) {
7081 CharacterLiteral::CharacterKind Kind;
7082 if (T->isWideCharType())
7083 Kind = CharacterLiteral::Wide;
7084 else if (T->isChar8Type() && getLangOpts().Char8)
7085 Kind = CharacterLiteral::UTF8;
7086 else if (T->isChar16Type())
7087 Kind = CharacterLiteral::UTF16;
7088 else if (T->isChar32Type())
7089 Kind = CharacterLiteral::UTF32;
7091 Kind = CharacterLiteral::Ascii;
7093 E = new (Context) CharacterLiteral(Arg.getAsIntegral().getZExtValue(),
7095 } else if (T->isBooleanType()) {
7096 E = new (Context) CXXBoolLiteralExpr(Arg.getAsIntegral().getBoolValue(),
7098 } else if (T->isNullPtrType()) {
7099 E = new (Context) CXXNullPtrLiteralExpr(Context.NullPtrTy, Loc);
7101 E = IntegerLiteral::Create(Context, Arg.getAsIntegral(), T, Loc);
7104 if (OrigT->isEnumeralType()) {
7105 // FIXME: This is a hack. We need a better way to handle substituted
7106 // non-type template parameters.
7107 E = CStyleCastExpr::Create(Context, OrigT, VK_RValue, CK_IntegralCast, E,
7109 Context.getTrivialTypeSourceInfo(OrigT, Loc),
7116 /// Match two template parameters within template parameter lists.
7117 static bool MatchTemplateParameterKind(Sema &S, NamedDecl *New, NamedDecl *Old,
7119 Sema::TemplateParameterListEqualKind Kind,
7120 SourceLocation TemplateArgLoc) {
7121 // Check the actual kind (type, non-type, template).
7122 if (Old->getKind() != New->getKind()) {
7124 unsigned NextDiag = diag::err_template_param_different_kind;
7125 if (TemplateArgLoc.isValid()) {
7126 S.Diag(TemplateArgLoc, diag::err_template_arg_template_params_mismatch);
7127 NextDiag = diag::note_template_param_different_kind;
7129 S.Diag(New->getLocation(), NextDiag)
7130 << (Kind != Sema::TPL_TemplateMatch);
7131 S.Diag(Old->getLocation(), diag::note_template_prev_declaration)
7132 << (Kind != Sema::TPL_TemplateMatch);
7138 // Check that both are parameter packs or neither are parameter packs.
7139 // However, if we are matching a template template argument to a
7140 // template template parameter, the template template parameter can have
7141 // a parameter pack where the template template argument does not.
7142 if (Old->isTemplateParameterPack() != New->isTemplateParameterPack() &&
7143 !(Kind == Sema::TPL_TemplateTemplateArgumentMatch &&
7144 Old->isTemplateParameterPack())) {
7146 unsigned NextDiag = diag::err_template_parameter_pack_non_pack;
7147 if (TemplateArgLoc.isValid()) {
7148 S.Diag(TemplateArgLoc,
7149 diag::err_template_arg_template_params_mismatch);
7150 NextDiag = diag::note_template_parameter_pack_non_pack;
7153 unsigned ParamKind = isa<TemplateTypeParmDecl>(New)? 0
7154 : isa<NonTypeTemplateParmDecl>(New)? 1
7156 S.Diag(New->getLocation(), NextDiag)
7157 << ParamKind << New->isParameterPack();
7158 S.Diag(Old->getLocation(), diag::note_template_parameter_pack_here)
7159 << ParamKind << Old->isParameterPack();
7165 // For non-type template parameters, check the type of the parameter.
7166 if (NonTypeTemplateParmDecl *OldNTTP
7167 = dyn_cast<NonTypeTemplateParmDecl>(Old)) {
7168 NonTypeTemplateParmDecl *NewNTTP = cast<NonTypeTemplateParmDecl>(New);
7170 // If we are matching a template template argument to a template
7171 // template parameter and one of the non-type template parameter types
7172 // is dependent, then we must wait until template instantiation time
7173 // to actually compare the arguments.
7174 if (Kind == Sema::TPL_TemplateTemplateArgumentMatch &&
7175 (OldNTTP->getType()->isDependentType() ||
7176 NewNTTP->getType()->isDependentType()))
7179 if (!S.Context.hasSameType(OldNTTP->getType(), NewNTTP->getType())) {
7181 unsigned NextDiag = diag::err_template_nontype_parm_different_type;
7182 if (TemplateArgLoc.isValid()) {
7183 S.Diag(TemplateArgLoc,
7184 diag::err_template_arg_template_params_mismatch);
7185 NextDiag = diag::note_template_nontype_parm_different_type;
7187 S.Diag(NewNTTP->getLocation(), NextDiag)
7188 << NewNTTP->getType()
7189 << (Kind != Sema::TPL_TemplateMatch);
7190 S.Diag(OldNTTP->getLocation(),
7191 diag::note_template_nontype_parm_prev_declaration)
7192 << OldNTTP->getType();
7201 // For template template parameters, check the template parameter types.
7202 // The template parameter lists of template template
7203 // parameters must agree.
7204 if (TemplateTemplateParmDecl *OldTTP
7205 = dyn_cast<TemplateTemplateParmDecl>(Old)) {
7206 TemplateTemplateParmDecl *NewTTP = cast<TemplateTemplateParmDecl>(New);
7207 return S.TemplateParameterListsAreEqual(NewTTP->getTemplateParameters(),
7208 OldTTP->getTemplateParameters(),
7210 (Kind == Sema::TPL_TemplateMatch
7211 ? Sema::TPL_TemplateTemplateParmMatch
7219 /// Diagnose a known arity mismatch when comparing template argument
7222 void DiagnoseTemplateParameterListArityMismatch(Sema &S,
7223 TemplateParameterList *New,
7224 TemplateParameterList *Old,
7225 Sema::TemplateParameterListEqualKind Kind,
7226 SourceLocation TemplateArgLoc) {
7227 unsigned NextDiag = diag::err_template_param_list_different_arity;
7228 if (TemplateArgLoc.isValid()) {
7229 S.Diag(TemplateArgLoc, diag::err_template_arg_template_params_mismatch);
7230 NextDiag = diag::note_template_param_list_different_arity;
7232 S.Diag(New->getTemplateLoc(), NextDiag)
7233 << (New->size() > Old->size())
7234 << (Kind != Sema::TPL_TemplateMatch)
7235 << SourceRange(New->getTemplateLoc(), New->getRAngleLoc());
7236 S.Diag(Old->getTemplateLoc(), diag::note_template_prev_declaration)
7237 << (Kind != Sema::TPL_TemplateMatch)
7238 << SourceRange(Old->getTemplateLoc(), Old->getRAngleLoc());
7241 /// Determine whether the given template parameter lists are
7244 /// \param New The new template parameter list, typically written in the
7245 /// source code as part of a new template declaration.
7247 /// \param Old The old template parameter list, typically found via
7248 /// name lookup of the template declared with this template parameter
7251 /// \param Complain If true, this routine will produce a diagnostic if
7252 /// the template parameter lists are not equivalent.
7254 /// \param Kind describes how we are to match the template parameter lists.
7256 /// \param TemplateArgLoc If this source location is valid, then we
7257 /// are actually checking the template parameter list of a template
7258 /// argument (New) against the template parameter list of its
7259 /// corresponding template template parameter (Old). We produce
7260 /// slightly different diagnostics in this scenario.
7262 /// \returns True if the template parameter lists are equal, false
7265 Sema::TemplateParameterListsAreEqual(TemplateParameterList *New,
7266 TemplateParameterList *Old,
7268 TemplateParameterListEqualKind Kind,
7269 SourceLocation TemplateArgLoc) {
7270 if (Old->size() != New->size() && Kind != TPL_TemplateTemplateArgumentMatch) {
7272 DiagnoseTemplateParameterListArityMismatch(*this, New, Old, Kind,
7278 // C++0x [temp.arg.template]p3:
7279 // A template-argument matches a template template-parameter (call it P)
7280 // when each of the template parameters in the template-parameter-list of
7281 // the template-argument's corresponding class template or alias template
7282 // (call it A) matches the corresponding template parameter in the
7283 // template-parameter-list of P. [...]
7284 TemplateParameterList::iterator NewParm = New->begin();
7285 TemplateParameterList::iterator NewParmEnd = New->end();
7286 for (TemplateParameterList::iterator OldParm = Old->begin(),
7287 OldParmEnd = Old->end();
7288 OldParm != OldParmEnd; ++OldParm) {
7289 if (Kind != TPL_TemplateTemplateArgumentMatch ||
7290 !(*OldParm)->isTemplateParameterPack()) {
7291 if (NewParm == NewParmEnd) {
7293 DiagnoseTemplateParameterListArityMismatch(*this, New, Old, Kind,
7299 if (!MatchTemplateParameterKind(*this, *NewParm, *OldParm, Complain,
7300 Kind, TemplateArgLoc))
7307 // C++0x [temp.arg.template]p3:
7308 // [...] When P's template- parameter-list contains a template parameter
7309 // pack (14.5.3), the template parameter pack will match zero or more
7310 // template parameters or template parameter packs in the
7311 // template-parameter-list of A with the same type and form as the
7312 // template parameter pack in P (ignoring whether those template
7313 // parameters are template parameter packs).
7314 for (; NewParm != NewParmEnd; ++NewParm) {
7315 if (!MatchTemplateParameterKind(*this, *NewParm, *OldParm, Complain,
7316 Kind, TemplateArgLoc))
7321 // Make sure we exhausted all of the arguments.
7322 if (NewParm != NewParmEnd) {
7324 DiagnoseTemplateParameterListArityMismatch(*this, New, Old, Kind,
7333 /// Check whether a template can be declared within this scope.
7335 /// If the template declaration is valid in this scope, returns
7336 /// false. Otherwise, issues a diagnostic and returns true.
7338 Sema::CheckTemplateDeclScope(Scope *S, TemplateParameterList *TemplateParams) {
7342 // Find the nearest enclosing declaration scope.
7343 while ((S->getFlags() & Scope::DeclScope) == 0 ||
7344 (S->getFlags() & Scope::TemplateParamScope) != 0)
7348 // A template [...] shall not have C linkage.
7349 DeclContext *Ctx = S->getEntity();
7350 if (Ctx && Ctx->isExternCContext()) {
7351 Diag(TemplateParams->getTemplateLoc(), diag::err_template_linkage)
7352 << TemplateParams->getSourceRange();
7353 if (const LinkageSpecDecl *LSD = Ctx->getExternCContext())
7354 Diag(LSD->getExternLoc(), diag::note_extern_c_begins_here);
7357 Ctx = Ctx->getRedeclContext();
7360 // A template-declaration can appear only as a namespace scope or
7361 // class scope declaration.
7363 if (Ctx->isFileContext())
7365 if (CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(Ctx)) {
7366 // C++ [temp.mem]p2:
7367 // A local class shall not have member templates.
7368 if (RD->isLocalClass())
7369 return Diag(TemplateParams->getTemplateLoc(),
7370 diag::err_template_inside_local_class)
7371 << TemplateParams->getSourceRange();
7377 return Diag(TemplateParams->getTemplateLoc(),
7378 diag::err_template_outside_namespace_or_class_scope)
7379 << TemplateParams->getSourceRange();
7382 /// Determine what kind of template specialization the given declaration
7384 static TemplateSpecializationKind getTemplateSpecializationKind(Decl *D) {
7386 return TSK_Undeclared;
7388 if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(D))
7389 return Record->getTemplateSpecializationKind();
7390 if (FunctionDecl *Function = dyn_cast<FunctionDecl>(D))
7391 return Function->getTemplateSpecializationKind();
7392 if (VarDecl *Var = dyn_cast<VarDecl>(D))
7393 return Var->getTemplateSpecializationKind();
7395 return TSK_Undeclared;
7398 /// Check whether a specialization is well-formed in the current
7401 /// This routine determines whether a template specialization can be declared
7402 /// in the current context (C++ [temp.expl.spec]p2).
7404 /// \param S the semantic analysis object for which this check is being
7407 /// \param Specialized the entity being specialized or instantiated, which
7408 /// may be a kind of template (class template, function template, etc.) or
7409 /// a member of a class template (member function, static data member,
7412 /// \param PrevDecl the previous declaration of this entity, if any.
7414 /// \param Loc the location of the explicit specialization or instantiation of
7417 /// \param IsPartialSpecialization whether this is a partial specialization of
7418 /// a class template.
7420 /// \returns true if there was an error that we cannot recover from, false
7422 static bool CheckTemplateSpecializationScope(Sema &S,
7423 NamedDecl *Specialized,
7424 NamedDecl *PrevDecl,
7426 bool IsPartialSpecialization) {
7427 // Keep these "kind" numbers in sync with the %select statements in the
7428 // various diagnostics emitted by this routine.
7430 if (isa<ClassTemplateDecl>(Specialized))
7431 EntityKind = IsPartialSpecialization? 1 : 0;
7432 else if (isa<VarTemplateDecl>(Specialized))
7433 EntityKind = IsPartialSpecialization ? 3 : 2;
7434 else if (isa<FunctionTemplateDecl>(Specialized))
7436 else if (isa<CXXMethodDecl>(Specialized))
7438 else if (isa<VarDecl>(Specialized))
7440 else if (isa<RecordDecl>(Specialized))
7442 else if (isa<EnumDecl>(Specialized) && S.getLangOpts().CPlusPlus11)
7445 S.Diag(Loc, diag::err_template_spec_unknown_kind)
7446 << S.getLangOpts().CPlusPlus11;
7447 S.Diag(Specialized->getLocation(), diag::note_specialized_entity);
7451 // C++ [temp.expl.spec]p2:
7452 // An explicit specialization may be declared in any scope in which
7453 // the corresponding primary template may be defined.
7454 if (S.CurContext->getRedeclContext()->isFunctionOrMethod()) {
7455 S.Diag(Loc, diag::err_template_spec_decl_function_scope)
7460 // C++ [temp.class.spec]p6:
7461 // A class template partial specialization may be declared in any
7462 // scope in which the primary template may be defined.
7463 DeclContext *SpecializedContext =
7464 Specialized->getDeclContext()->getRedeclContext();
7465 DeclContext *DC = S.CurContext->getRedeclContext();
7467 // Make sure that this redeclaration (or definition) occurs in the same
7468 // scope or an enclosing namespace.
7469 if (!(DC->isFileContext() ? DC->Encloses(SpecializedContext)
7470 : DC->Equals(SpecializedContext))) {
7471 if (isa<TranslationUnitDecl>(SpecializedContext))
7472 S.Diag(Loc, diag::err_template_spec_redecl_global_scope)
7473 << EntityKind << Specialized;
7475 auto *ND = cast<NamedDecl>(SpecializedContext);
7476 int Diag = diag::err_template_spec_redecl_out_of_scope;
7477 if (S.getLangOpts().MicrosoftExt && !DC->isRecord())
7478 Diag = diag::ext_ms_template_spec_redecl_out_of_scope;
7479 S.Diag(Loc, Diag) << EntityKind << Specialized
7480 << ND << isa<CXXRecordDecl>(ND);
7483 S.Diag(Specialized->getLocation(), diag::note_specialized_entity);
7485 // Don't allow specializing in the wrong class during error recovery.
7486 // Otherwise, things can go horribly wrong.
7494 static SourceRange findTemplateParameterInType(unsigned Depth, Expr *E) {
7495 if (!E->isTypeDependent())
7496 return SourceLocation();
7497 DependencyChecker Checker(Depth, /*IgnoreNonTypeDependent*/true);
7498 Checker.TraverseStmt(E);
7499 if (Checker.MatchLoc.isInvalid())
7500 return E->getSourceRange();
7501 return Checker.MatchLoc;
7504 static SourceRange findTemplateParameter(unsigned Depth, TypeLoc TL) {
7505 if (!TL.getType()->isDependentType())
7506 return SourceLocation();
7507 DependencyChecker Checker(Depth, /*IgnoreNonTypeDependent*/true);
7508 Checker.TraverseTypeLoc(TL);
7509 if (Checker.MatchLoc.isInvalid())
7510 return TL.getSourceRange();
7511 return Checker.MatchLoc;
7514 /// Subroutine of Sema::CheckTemplatePartialSpecializationArgs
7515 /// that checks non-type template partial specialization arguments.
7516 static bool CheckNonTypeTemplatePartialSpecializationArgs(
7517 Sema &S, SourceLocation TemplateNameLoc, NonTypeTemplateParmDecl *Param,
7518 const TemplateArgument *Args, unsigned NumArgs, bool IsDefaultArgument) {
7519 for (unsigned I = 0; I != NumArgs; ++I) {
7520 if (Args[I].getKind() == TemplateArgument::Pack) {
7521 if (CheckNonTypeTemplatePartialSpecializationArgs(
7522 S, TemplateNameLoc, Param, Args[I].pack_begin(),
7523 Args[I].pack_size(), IsDefaultArgument))
7529 if (Args[I].getKind() != TemplateArgument::Expression)
7532 Expr *ArgExpr = Args[I].getAsExpr();
7534 // We can have a pack expansion of any of the bullets below.
7535 if (PackExpansionExpr *Expansion = dyn_cast<PackExpansionExpr>(ArgExpr))
7536 ArgExpr = Expansion->getPattern();
7538 // Strip off any implicit casts we added as part of type checking.
7539 while (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(ArgExpr))
7540 ArgExpr = ICE->getSubExpr();
7542 // C++ [temp.class.spec]p8:
7543 // A non-type argument is non-specialized if it is the name of a
7544 // non-type parameter. All other non-type arguments are
7547 // Below, we check the two conditions that only apply to
7548 // specialized non-type arguments, so skip any non-specialized
7550 if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(ArgExpr))
7551 if (isa<NonTypeTemplateParmDecl>(DRE->getDecl()))
7554 // C++ [temp.class.spec]p9:
7555 // Within the argument list of a class template partial
7556 // specialization, the following restrictions apply:
7557 // -- A partially specialized non-type argument expression
7558 // shall not involve a template parameter of the partial
7559 // specialization except when the argument expression is a
7560 // simple identifier.
7561 // -- The type of a template parameter corresponding to a
7562 // specialized non-type argument shall not be dependent on a
7563 // parameter of the specialization.
7564 // DR1315 removes the first bullet, leaving an incoherent set of rules.
7565 // We implement a compromise between the original rules and DR1315:
7566 // -- A specialized non-type template argument shall not be
7567 // type-dependent and the corresponding template parameter
7568 // shall have a non-dependent type.
7569 SourceRange ParamUseRange =
7570 findTemplateParameterInType(Param->getDepth(), ArgExpr);
7571 if (ParamUseRange.isValid()) {
7572 if (IsDefaultArgument) {
7573 S.Diag(TemplateNameLoc,
7574 diag::err_dependent_non_type_arg_in_partial_spec);
7575 S.Diag(ParamUseRange.getBegin(),
7576 diag::note_dependent_non_type_default_arg_in_partial_spec)
7579 S.Diag(ParamUseRange.getBegin(),
7580 diag::err_dependent_non_type_arg_in_partial_spec)
7586 ParamUseRange = findTemplateParameter(
7587 Param->getDepth(), Param->getTypeSourceInfo()->getTypeLoc());
7588 if (ParamUseRange.isValid()) {
7589 S.Diag(IsDefaultArgument ? TemplateNameLoc : ArgExpr->getBeginLoc(),
7590 diag::err_dependent_typed_non_type_arg_in_partial_spec)
7591 << Param->getType();
7592 S.Diag(Param->getLocation(), diag::note_template_param_here)
7593 << (IsDefaultArgument ? ParamUseRange : SourceRange())
7602 /// Check the non-type template arguments of a class template
7603 /// partial specialization according to C++ [temp.class.spec]p9.
7605 /// \param TemplateNameLoc the location of the template name.
7606 /// \param PrimaryTemplate the template parameters of the primary class
7608 /// \param NumExplicit the number of explicitly-specified template arguments.
7609 /// \param TemplateArgs the template arguments of the class template
7610 /// partial specialization.
7612 /// \returns \c true if there was an error, \c false otherwise.
7613 bool Sema::CheckTemplatePartialSpecializationArgs(
7614 SourceLocation TemplateNameLoc, TemplateDecl *PrimaryTemplate,
7615 unsigned NumExplicit, ArrayRef<TemplateArgument> TemplateArgs) {
7616 // We have to be conservative when checking a template in a dependent
7618 if (PrimaryTemplate->getDeclContext()->isDependentContext())
7621 TemplateParameterList *TemplateParams =
7622 PrimaryTemplate->getTemplateParameters();
7623 for (unsigned I = 0, N = TemplateParams->size(); I != N; ++I) {
7624 NonTypeTemplateParmDecl *Param
7625 = dyn_cast<NonTypeTemplateParmDecl>(TemplateParams->getParam(I));
7629 if (CheckNonTypeTemplatePartialSpecializationArgs(*this, TemplateNameLoc,
7630 Param, &TemplateArgs[I],
7631 1, I >= NumExplicit))
7638 DeclResult Sema::ActOnClassTemplateSpecialization(
7639 Scope *S, unsigned TagSpec, TagUseKind TUK, SourceLocation KWLoc,
7640 SourceLocation ModulePrivateLoc, TemplateIdAnnotation &TemplateId,
7641 const ParsedAttributesView &Attr,
7642 MultiTemplateParamsArg TemplateParameterLists, SkipBodyInfo *SkipBody) {
7643 assert(TUK != TUK_Reference && "References are not specializations");
7645 CXXScopeSpec &SS = TemplateId.SS;
7647 // NOTE: KWLoc is the location of the tag keyword. This will instead
7648 // store the location of the outermost template keyword in the declaration.
7649 SourceLocation TemplateKWLoc = TemplateParameterLists.size() > 0
7650 ? TemplateParameterLists[0]->getTemplateLoc() : KWLoc;
7651 SourceLocation TemplateNameLoc = TemplateId.TemplateNameLoc;
7652 SourceLocation LAngleLoc = TemplateId.LAngleLoc;
7653 SourceLocation RAngleLoc = TemplateId.RAngleLoc;
7655 // Find the class template we're specializing
7656 TemplateName Name = TemplateId.Template.get();
7657 ClassTemplateDecl *ClassTemplate
7658 = dyn_cast_or_null<ClassTemplateDecl>(Name.getAsTemplateDecl());
7660 if (!ClassTemplate) {
7661 Diag(TemplateNameLoc, diag::err_not_class_template_specialization)
7662 << (Name.getAsTemplateDecl() &&
7663 isa<TemplateTemplateParmDecl>(Name.getAsTemplateDecl()));
7667 bool isMemberSpecialization = false;
7668 bool isPartialSpecialization = false;
7670 // Check the validity of the template headers that introduce this
7672 // FIXME: We probably shouldn't complain about these headers for
7673 // friend declarations.
7674 bool Invalid = false;
7675 TemplateParameterList *TemplateParams =
7676 MatchTemplateParametersToScopeSpecifier(
7677 KWLoc, TemplateNameLoc, SS, &TemplateId,
7678 TemplateParameterLists, TUK == TUK_Friend, isMemberSpecialization,
7683 if (TemplateParams && TemplateParams->size() > 0) {
7684 isPartialSpecialization = true;
7686 if (TUK == TUK_Friend) {
7687 Diag(KWLoc, diag::err_partial_specialization_friend)
7688 << SourceRange(LAngleLoc, RAngleLoc);
7692 // C++ [temp.class.spec]p10:
7693 // The template parameter list of a specialization shall not
7694 // contain default template argument values.
7695 for (unsigned I = 0, N = TemplateParams->size(); I != N; ++I) {
7696 Decl *Param = TemplateParams->getParam(I);
7697 if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(Param)) {
7698 if (TTP->hasDefaultArgument()) {
7699 Diag(TTP->getDefaultArgumentLoc(),
7700 diag::err_default_arg_in_partial_spec);
7701 TTP->removeDefaultArgument();
7703 } else if (NonTypeTemplateParmDecl *NTTP
7704 = dyn_cast<NonTypeTemplateParmDecl>(Param)) {
7705 if (Expr *DefArg = NTTP->getDefaultArgument()) {
7706 Diag(NTTP->getDefaultArgumentLoc(),
7707 diag::err_default_arg_in_partial_spec)
7708 << DefArg->getSourceRange();
7709 NTTP->removeDefaultArgument();
7712 TemplateTemplateParmDecl *TTP = cast<TemplateTemplateParmDecl>(Param);
7713 if (TTP->hasDefaultArgument()) {
7714 Diag(TTP->getDefaultArgument().getLocation(),
7715 diag::err_default_arg_in_partial_spec)
7716 << TTP->getDefaultArgument().getSourceRange();
7717 TTP->removeDefaultArgument();
7721 } else if (TemplateParams) {
7722 if (TUK == TUK_Friend)
7723 Diag(KWLoc, diag::err_template_spec_friend)
7724 << FixItHint::CreateRemoval(
7725 SourceRange(TemplateParams->getTemplateLoc(),
7726 TemplateParams->getRAngleLoc()))
7727 << SourceRange(LAngleLoc, RAngleLoc);
7729 assert(TUK == TUK_Friend && "should have a 'template<>' for this decl");
7732 // Check that the specialization uses the same tag kind as the
7733 // original template.
7734 TagTypeKind Kind = TypeWithKeyword::getTagTypeKindForTypeSpec(TagSpec);
7735 assert(Kind != TTK_Enum && "Invalid enum tag in class template spec!");
7736 if (!isAcceptableTagRedeclaration(ClassTemplate->getTemplatedDecl(),
7737 Kind, TUK == TUK_Definition, KWLoc,
7738 ClassTemplate->getIdentifier())) {
7739 Diag(KWLoc, diag::err_use_with_wrong_tag)
7741 << FixItHint::CreateReplacement(KWLoc,
7742 ClassTemplate->getTemplatedDecl()->getKindName());
7743 Diag(ClassTemplate->getTemplatedDecl()->getLocation(),
7744 diag::note_previous_use);
7745 Kind = ClassTemplate->getTemplatedDecl()->getTagKind();
7748 // Translate the parser's template argument list in our AST format.
7749 TemplateArgumentListInfo TemplateArgs =
7750 makeTemplateArgumentListInfo(*this, TemplateId);
7752 // Check for unexpanded parameter packs in any of the template arguments.
7753 for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I)
7754 if (DiagnoseUnexpandedParameterPack(TemplateArgs[I],
7755 UPPC_PartialSpecialization))
7758 // Check that the template argument list is well-formed for this
7760 SmallVector<TemplateArgument, 4> Converted;
7761 if (CheckTemplateArgumentList(ClassTemplate, TemplateNameLoc,
7762 TemplateArgs, false, Converted))
7765 // Find the class template (partial) specialization declaration that
7766 // corresponds to these arguments.
7767 if (isPartialSpecialization) {
7768 if (CheckTemplatePartialSpecializationArgs(TemplateNameLoc, ClassTemplate,
7769 TemplateArgs.size(), Converted))
7772 // FIXME: Move this to CheckTemplatePartialSpecializationArgs so we
7773 // also do it during instantiation.
7774 bool InstantiationDependent;
7775 if (!Name.isDependent() &&
7776 !TemplateSpecializationType::anyDependentTemplateArguments(
7777 TemplateArgs.arguments(), InstantiationDependent)) {
7778 Diag(TemplateNameLoc, diag::err_partial_spec_fully_specialized)
7779 << ClassTemplate->getDeclName();
7780 isPartialSpecialization = false;
7784 void *InsertPos = nullptr;
7785 ClassTemplateSpecializationDecl *PrevDecl = nullptr;
7787 if (isPartialSpecialization)
7788 // FIXME: Template parameter list matters, too
7789 PrevDecl = ClassTemplate->findPartialSpecialization(Converted, InsertPos);
7791 PrevDecl = ClassTemplate->findSpecialization(Converted, InsertPos);
7793 ClassTemplateSpecializationDecl *Specialization = nullptr;
7795 // Check whether we can declare a class template specialization in
7796 // the current scope.
7797 if (TUK != TUK_Friend &&
7798 CheckTemplateSpecializationScope(*this, ClassTemplate, PrevDecl,
7800 isPartialSpecialization))
7803 // The canonical type
7805 if (isPartialSpecialization) {
7806 // Build the canonical type that describes the converted template
7807 // arguments of the class template partial specialization.
7808 TemplateName CanonTemplate = Context.getCanonicalTemplateName(Name);
7809 CanonType = Context.getTemplateSpecializationType(CanonTemplate,
7812 if (Context.hasSameType(CanonType,
7813 ClassTemplate->getInjectedClassNameSpecialization())) {
7814 // C++ [temp.class.spec]p9b3:
7816 // -- The argument list of the specialization shall not be identical
7817 // to the implicit argument list of the primary template.
7819 // This rule has since been removed, because it's redundant given DR1495,
7820 // but we keep it because it produces better diagnostics and recovery.
7821 Diag(TemplateNameLoc, diag::err_partial_spec_args_match_primary_template)
7822 << /*class template*/0 << (TUK == TUK_Definition)
7823 << FixItHint::CreateRemoval(SourceRange(LAngleLoc, RAngleLoc));
7824 return CheckClassTemplate(S, TagSpec, TUK, KWLoc, SS,
7825 ClassTemplate->getIdentifier(),
7829 AS_none, /*ModulePrivateLoc=*/SourceLocation(),
7830 /*FriendLoc*/SourceLocation(),
7831 TemplateParameterLists.size() - 1,
7832 TemplateParameterLists.data());
7835 // Create a new class template partial specialization declaration node.
7836 ClassTemplatePartialSpecializationDecl *PrevPartial
7837 = cast_or_null<ClassTemplatePartialSpecializationDecl>(PrevDecl);
7838 ClassTemplatePartialSpecializationDecl *Partial
7839 = ClassTemplatePartialSpecializationDecl::Create(Context, Kind,
7840 ClassTemplate->getDeclContext(),
7841 KWLoc, TemplateNameLoc,
7848 SetNestedNameSpecifier(*this, Partial, SS);
7849 if (TemplateParameterLists.size() > 1 && SS.isSet()) {
7850 Partial->setTemplateParameterListsInfo(
7851 Context, TemplateParameterLists.drop_back(1));
7855 ClassTemplate->AddPartialSpecialization(Partial, InsertPos);
7856 Specialization = Partial;
7858 // If we are providing an explicit specialization of a member class
7859 // template specialization, make a note of that.
7860 if (PrevPartial && PrevPartial->getInstantiatedFromMember())
7861 PrevPartial->setMemberSpecialization();
7863 CheckTemplatePartialSpecialization(Partial);
7865 // Create a new class template specialization declaration node for
7866 // this explicit specialization or friend declaration.
7868 = ClassTemplateSpecializationDecl::Create(Context, Kind,
7869 ClassTemplate->getDeclContext(),
7870 KWLoc, TemplateNameLoc,
7874 SetNestedNameSpecifier(*this, Specialization, SS);
7875 if (TemplateParameterLists.size() > 0) {
7876 Specialization->setTemplateParameterListsInfo(Context,
7877 TemplateParameterLists);
7881 ClassTemplate->AddSpecialization(Specialization, InsertPos);
7883 if (CurContext->isDependentContext()) {
7884 TemplateName CanonTemplate = Context.getCanonicalTemplateName(Name);
7885 CanonType = Context.getTemplateSpecializationType(
7886 CanonTemplate, Converted);
7888 CanonType = Context.getTypeDeclType(Specialization);
7892 // C++ [temp.expl.spec]p6:
7893 // If a template, a member template or the member of a class template is
7894 // explicitly specialized then that specialization shall be declared
7895 // before the first use of that specialization that would cause an implicit
7896 // instantiation to take place, in every translation unit in which such a
7897 // use occurs; no diagnostic is required.
7898 if (PrevDecl && PrevDecl->getPointOfInstantiation().isValid()) {
7900 for (Decl *Prev = PrevDecl; Prev; Prev = Prev->getPreviousDecl()) {
7901 // Is there any previous explicit specialization declaration?
7902 if (getTemplateSpecializationKind(Prev) == TSK_ExplicitSpecialization) {
7909 SourceRange Range(TemplateNameLoc, RAngleLoc);
7910 Diag(TemplateNameLoc, diag::err_specialization_after_instantiation)
7911 << Context.getTypeDeclType(Specialization) << Range;
7913 Diag(PrevDecl->getPointOfInstantiation(),
7914 diag::note_instantiation_required_here)
7915 << (PrevDecl->getTemplateSpecializationKind()
7916 != TSK_ImplicitInstantiation);
7921 // If this is not a friend, note that this is an explicit specialization.
7922 if (TUK != TUK_Friend)
7923 Specialization->setSpecializationKind(TSK_ExplicitSpecialization);
7925 // Check that this isn't a redefinition of this specialization.
7926 if (TUK == TUK_Definition) {
7927 RecordDecl *Def = Specialization->getDefinition();
7928 NamedDecl *Hidden = nullptr;
7929 if (Def && SkipBody && !hasVisibleDefinition(Def, &Hidden)) {
7930 SkipBody->ShouldSkip = true;
7931 SkipBody->Previous = Def;
7932 makeMergedDefinitionVisible(Hidden);
7934 SourceRange Range(TemplateNameLoc, RAngleLoc);
7935 Diag(TemplateNameLoc, diag::err_redefinition) << Specialization << Range;
7936 Diag(Def->getLocation(), diag::note_previous_definition);
7937 Specialization->setInvalidDecl();
7942 ProcessDeclAttributeList(S, Specialization, Attr);
7944 // Add alignment attributes if necessary; these attributes are checked when
7945 // the ASTContext lays out the structure.
7946 if (TUK == TUK_Definition && (!SkipBody || !SkipBody->ShouldSkip)) {
7947 AddAlignmentAttributesForRecord(Specialization);
7948 AddMsStructLayoutForRecord(Specialization);
7951 if (ModulePrivateLoc.isValid())
7952 Diag(Specialization->getLocation(), diag::err_module_private_specialization)
7953 << (isPartialSpecialization? 1 : 0)
7954 << FixItHint::CreateRemoval(ModulePrivateLoc);
7956 // Build the fully-sugared type for this class template
7957 // specialization as the user wrote in the specialization
7958 // itself. This means that we'll pretty-print the type retrieved
7959 // from the specialization's declaration the way that the user
7960 // actually wrote the specialization, rather than formatting the
7961 // name based on the "canonical" representation used to store the
7962 // template arguments in the specialization.
7963 TypeSourceInfo *WrittenTy
7964 = Context.getTemplateSpecializationTypeInfo(Name, TemplateNameLoc,
7965 TemplateArgs, CanonType);
7966 if (TUK != TUK_Friend) {
7967 Specialization->setTypeAsWritten(WrittenTy);
7968 Specialization->setTemplateKeywordLoc(TemplateKWLoc);
7971 // C++ [temp.expl.spec]p9:
7972 // A template explicit specialization is in the scope of the
7973 // namespace in which the template was defined.
7975 // We actually implement this paragraph where we set the semantic
7976 // context (in the creation of the ClassTemplateSpecializationDecl),
7977 // but we also maintain the lexical context where the actual
7978 // definition occurs.
7979 Specialization->setLexicalDeclContext(CurContext);
7981 // We may be starting the definition of this specialization.
7982 if (TUK == TUK_Definition && (!SkipBody || !SkipBody->ShouldSkip))
7983 Specialization->startDefinition();
7985 if (TUK == TUK_Friend) {
7986 FriendDecl *Friend = FriendDecl::Create(Context, CurContext,
7990 Friend->setAccess(AS_public);
7991 CurContext->addDecl(Friend);
7993 // Add the specialization into its lexical context, so that it can
7994 // be seen when iterating through the list of declarations in that
7995 // context. However, specializations are not found by name lookup.
7996 CurContext->addDecl(Specialization);
7999 if (SkipBody && SkipBody->ShouldSkip)
8000 return SkipBody->Previous;
8002 return Specialization;
8005 Decl *Sema::ActOnTemplateDeclarator(Scope *S,
8006 MultiTemplateParamsArg TemplateParameterLists,
8008 Decl *NewDecl = HandleDeclarator(S, D, TemplateParameterLists);
8009 ActOnDocumentableDecl(NewDecl);
8013 Decl *Sema::ActOnConceptDefinition(Scope *S,
8014 MultiTemplateParamsArg TemplateParameterLists,
8015 IdentifierInfo *Name, SourceLocation NameLoc,
8016 Expr *ConstraintExpr) {
8017 DeclContext *DC = CurContext;
8019 if (!DC->getRedeclContext()->isFileContext()) {
8021 diag::err_concept_decls_may_only_appear_in_global_namespace_scope);
8025 if (TemplateParameterLists.size() > 1) {
8026 Diag(NameLoc, diag::err_concept_extra_headers);
8030 if (TemplateParameterLists.front()->size() == 0) {
8031 Diag(NameLoc, diag::err_concept_no_parameters);
8035 ConceptDecl *NewDecl = ConceptDecl::Create(Context, DC, NameLoc, Name,
8036 TemplateParameterLists.front(),
8039 if (!ConstraintExpr->isTypeDependent() &&
8040 ConstraintExpr->getType() != Context.BoolTy) {
8041 // C++2a [temp.constr.atomic]p3:
8042 // E shall be a constant expression of type bool.
8043 // TODO: Do this check for individual atomic constraints
8044 // and not the constraint expression. Probably should do it in
8045 // ParseConstraintExpression.
8046 Diag(ConstraintExpr->getSourceRange().getBegin(),
8047 diag::err_concept_initialized_with_non_bool_type)
8048 << ConstraintExpr->getType();
8049 NewDecl->setInvalidDecl();
8052 if (NewDecl->getAssociatedConstraints()) {
8053 // C++2a [temp.concept]p4:
8054 // A concept shall not have associated constraints.
8055 // TODO: Make a test once we have actual associated constraints.
8056 Diag(NameLoc, diag::err_concept_no_associated_constraints);
8057 NewDecl->setInvalidDecl();
8060 // Check for conflicting previous declaration.
8061 DeclarationNameInfo NameInfo(NewDecl->getDeclName(), NameLoc);
8062 LookupResult Previous(*this, NameInfo, LookupOrdinaryName,
8063 ForVisibleRedeclaration);
8064 LookupName(Previous, S);
8066 FilterLookupForScope(Previous, DC, S, /*ConsiderLinkage=*/false,
8067 /*AllowInlineNamespace*/false);
8068 if (!Previous.empty()) {
8069 auto *Old = Previous.getRepresentativeDecl();
8070 Diag(NameLoc, isa<ConceptDecl>(Old) ? diag::err_redefinition :
8071 diag::err_redefinition_different_kind) << NewDecl->getDeclName();
8072 Diag(Old->getLocation(), diag::note_previous_definition);
8075 ActOnDocumentableDecl(NewDecl);
8076 PushOnScopeChains(NewDecl, S);
8080 /// \brief Strips various properties off an implicit instantiation
8081 /// that has just been explicitly specialized.
8082 static void StripImplicitInstantiation(NamedDecl *D) {
8083 D->dropAttr<DLLImportAttr>();
8084 D->dropAttr<DLLExportAttr>();
8086 if (FunctionDecl *FD = dyn_cast<FunctionDecl>(D))
8087 FD->setInlineSpecified(false);
8090 /// Compute the diagnostic location for an explicit instantiation
8091 // declaration or definition.
8092 static SourceLocation DiagLocForExplicitInstantiation(
8093 NamedDecl* D, SourceLocation PointOfInstantiation) {
8094 // Explicit instantiations following a specialization have no effect and
8095 // hence no PointOfInstantiation. In that case, walk decl backwards
8096 // until a valid name loc is found.
8097 SourceLocation PrevDiagLoc = PointOfInstantiation;
8098 for (Decl *Prev = D; Prev && !PrevDiagLoc.isValid();
8099 Prev = Prev->getPreviousDecl()) {
8100 PrevDiagLoc = Prev->getLocation();
8102 assert(PrevDiagLoc.isValid() &&
8103 "Explicit instantiation without point of instantiation?");
8107 /// Diagnose cases where we have an explicit template specialization
8108 /// before/after an explicit template instantiation, producing diagnostics
8109 /// for those cases where they are required and determining whether the
8110 /// new specialization/instantiation will have any effect.
8112 /// \param NewLoc the location of the new explicit specialization or
8115 /// \param NewTSK the kind of the new explicit specialization or instantiation.
8117 /// \param PrevDecl the previous declaration of the entity.
8119 /// \param PrevTSK the kind of the old explicit specialization or instantiatin.
8121 /// \param PrevPointOfInstantiation if valid, indicates where the previus
8122 /// declaration was instantiated (either implicitly or explicitly).
8124 /// \param HasNoEffect will be set to true to indicate that the new
8125 /// specialization or instantiation has no effect and should be ignored.
8127 /// \returns true if there was an error that should prevent the introduction of
8128 /// the new declaration into the AST, false otherwise.
8130 Sema::CheckSpecializationInstantiationRedecl(SourceLocation NewLoc,
8131 TemplateSpecializationKind NewTSK,
8132 NamedDecl *PrevDecl,
8133 TemplateSpecializationKind PrevTSK,
8134 SourceLocation PrevPointOfInstantiation,
8135 bool &HasNoEffect) {
8136 HasNoEffect = false;
8139 case TSK_Undeclared:
8140 case TSK_ImplicitInstantiation:
8142 (PrevTSK == TSK_Undeclared || PrevTSK == TSK_ImplicitInstantiation) &&
8143 "previous declaration must be implicit!");
8146 case TSK_ExplicitSpecialization:
8148 case TSK_Undeclared:
8149 case TSK_ExplicitSpecialization:
8150 // Okay, we're just specializing something that is either already
8151 // explicitly specialized or has merely been mentioned without any
8155 case TSK_ImplicitInstantiation:
8156 if (PrevPointOfInstantiation.isInvalid()) {
8157 // The declaration itself has not actually been instantiated, so it is
8158 // still okay to specialize it.
8159 StripImplicitInstantiation(PrevDecl);
8165 case TSK_ExplicitInstantiationDeclaration:
8166 case TSK_ExplicitInstantiationDefinition:
8167 assert((PrevTSK == TSK_ImplicitInstantiation ||
8168 PrevPointOfInstantiation.isValid()) &&
8169 "Explicit instantiation without point of instantiation?");
8171 // C++ [temp.expl.spec]p6:
8172 // If a template, a member template or the member of a class template
8173 // is explicitly specialized then that specialization shall be declared
8174 // before the first use of that specialization that would cause an
8175 // implicit instantiation to take place, in every translation unit in
8176 // which such a use occurs; no diagnostic is required.
8177 for (Decl *Prev = PrevDecl; Prev; Prev = Prev->getPreviousDecl()) {
8178 // Is there any previous explicit specialization declaration?
8179 if (getTemplateSpecializationKind(Prev) == TSK_ExplicitSpecialization)
8183 Diag(NewLoc, diag::err_specialization_after_instantiation)
8185 Diag(PrevPointOfInstantiation, diag::note_instantiation_required_here)
8186 << (PrevTSK != TSK_ImplicitInstantiation);
8190 llvm_unreachable("The switch over PrevTSK must be exhaustive.");
8192 case TSK_ExplicitInstantiationDeclaration:
8194 case TSK_ExplicitInstantiationDeclaration:
8195 // This explicit instantiation declaration is redundant (that's okay).
8199 case TSK_Undeclared:
8200 case TSK_ImplicitInstantiation:
8201 // We're explicitly instantiating something that may have already been
8202 // implicitly instantiated; that's fine.
8205 case TSK_ExplicitSpecialization:
8206 // C++0x [temp.explicit]p4:
8207 // For a given set of template parameters, if an explicit instantiation
8208 // of a template appears after a declaration of an explicit
8209 // specialization for that template, the explicit instantiation has no
8214 case TSK_ExplicitInstantiationDefinition:
8215 // C++0x [temp.explicit]p10:
8216 // If an entity is the subject of both an explicit instantiation
8217 // declaration and an explicit instantiation definition in the same
8218 // translation unit, the definition shall follow the declaration.
8220 diag::err_explicit_instantiation_declaration_after_definition);
8222 // Explicit instantiations following a specialization have no effect and
8223 // hence no PrevPointOfInstantiation. In that case, walk decl backwards
8224 // until a valid name loc is found.
8225 Diag(DiagLocForExplicitInstantiation(PrevDecl, PrevPointOfInstantiation),
8226 diag::note_explicit_instantiation_definition_here);
8230 llvm_unreachable("Unexpected TemplateSpecializationKind!");
8232 case TSK_ExplicitInstantiationDefinition:
8234 case TSK_Undeclared:
8235 case TSK_ImplicitInstantiation:
8236 // We're explicitly instantiating something that may have already been
8237 // implicitly instantiated; that's fine.
8240 case TSK_ExplicitSpecialization:
8241 // C++ DR 259, C++0x [temp.explicit]p4:
8242 // For a given set of template parameters, if an explicit
8243 // instantiation of a template appears after a declaration of
8244 // an explicit specialization for that template, the explicit
8245 // instantiation has no effect.
8246 Diag(NewLoc, diag::warn_explicit_instantiation_after_specialization)
8248 Diag(PrevDecl->getLocation(),
8249 diag::note_previous_template_specialization);
8253 case TSK_ExplicitInstantiationDeclaration:
8254 // We're explicitly instantiating a definition for something for which we
8255 // were previously asked to suppress instantiations. That's fine.
8257 // C++0x [temp.explicit]p4:
8258 // For a given set of template parameters, if an explicit instantiation
8259 // of a template appears after a declaration of an explicit
8260 // specialization for that template, the explicit instantiation has no
8262 for (Decl *Prev = PrevDecl; Prev; Prev = Prev->getPreviousDecl()) {
8263 // Is there any previous explicit specialization declaration?
8264 if (getTemplateSpecializationKind(Prev) == TSK_ExplicitSpecialization) {
8272 case TSK_ExplicitInstantiationDefinition:
8273 // C++0x [temp.spec]p5:
8274 // For a given template and a given set of template-arguments,
8275 // - an explicit instantiation definition shall appear at most once
8278 // MSVCCompat: MSVC silently ignores duplicate explicit instantiations.
8279 Diag(NewLoc, (getLangOpts().MSVCCompat)
8280 ? diag::ext_explicit_instantiation_duplicate
8281 : diag::err_explicit_instantiation_duplicate)
8283 Diag(DiagLocForExplicitInstantiation(PrevDecl, PrevPointOfInstantiation),
8284 diag::note_previous_explicit_instantiation);
8290 llvm_unreachable("Missing specialization/instantiation case?");
8293 /// Perform semantic analysis for the given dependent function
8294 /// template specialization.
8296 /// The only possible way to get a dependent function template specialization
8297 /// is with a friend declaration, like so:
8300 /// template \<class T> void foo(T);
8301 /// template \<class T> class A {
8302 /// friend void foo<>(T);
8306 /// There really isn't any useful analysis we can do here, so we
8307 /// just store the information.
8309 Sema::CheckDependentFunctionTemplateSpecialization(FunctionDecl *FD,
8310 const TemplateArgumentListInfo &ExplicitTemplateArgs,
8311 LookupResult &Previous) {
8312 // Remove anything from Previous that isn't a function template in
8313 // the correct context.
8314 DeclContext *FDLookupContext = FD->getDeclContext()->getRedeclContext();
8315 LookupResult::Filter F = Previous.makeFilter();
8316 enum DiscardReason { NotAFunctionTemplate, NotAMemberOfEnclosing };
8317 SmallVector<std::pair<DiscardReason, Decl *>, 8> DiscardedCandidates;
8318 while (F.hasNext()) {
8319 NamedDecl *D = F.next()->getUnderlyingDecl();
8320 if (!isa<FunctionTemplateDecl>(D)) {
8322 DiscardedCandidates.push_back(std::make_pair(NotAFunctionTemplate, D));
8326 if (!FDLookupContext->InEnclosingNamespaceSetOf(
8327 D->getDeclContext()->getRedeclContext())) {
8329 DiscardedCandidates.push_back(std::make_pair(NotAMemberOfEnclosing, D));
8335 if (Previous.empty()) {
8336 Diag(FD->getLocation(),
8337 diag::err_dependent_function_template_spec_no_match);
8338 for (auto &P : DiscardedCandidates)
8339 Diag(P.second->getLocation(),
8340 diag::note_dependent_function_template_spec_discard_reason)
8345 FD->setDependentTemplateSpecialization(Context, Previous.asUnresolvedSet(),
8346 ExplicitTemplateArgs);
8350 /// Perform semantic analysis for the given function template
8353 /// This routine performs all of the semantic analysis required for an
8354 /// explicit function template specialization. On successful completion,
8355 /// the function declaration \p FD will become a function template
8358 /// \param FD the function declaration, which will be updated to become a
8359 /// function template specialization.
8361 /// \param ExplicitTemplateArgs the explicitly-provided template arguments,
8362 /// if any. Note that this may be valid info even when 0 arguments are
8363 /// explicitly provided as in, e.g., \c void sort<>(char*, char*);
8364 /// as it anyway contains info on the angle brackets locations.
8366 /// \param Previous the set of declarations that may be specialized by
8367 /// this function specialization.
8369 /// \param QualifiedFriend whether this is a lookup for a qualified friend
8370 /// declaration with no explicit template argument list that might be
8371 /// befriending a function template specialization.
8372 bool Sema::CheckFunctionTemplateSpecialization(
8373 FunctionDecl *FD, TemplateArgumentListInfo *ExplicitTemplateArgs,
8374 LookupResult &Previous, bool QualifiedFriend) {
8375 // The set of function template specializations that could match this
8376 // explicit function template specialization.
8377 UnresolvedSet<8> Candidates;
8378 TemplateSpecCandidateSet FailedCandidates(FD->getLocation(),
8379 /*ForTakingAddress=*/false);
8381 llvm::SmallDenseMap<FunctionDecl *, TemplateArgumentListInfo, 8>
8382 ConvertedTemplateArgs;
8384 DeclContext *FDLookupContext = FD->getDeclContext()->getRedeclContext();
8385 for (LookupResult::iterator I = Previous.begin(), E = Previous.end();
8387 NamedDecl *Ovl = (*I)->getUnderlyingDecl();
8388 if (FunctionTemplateDecl *FunTmpl = dyn_cast<FunctionTemplateDecl>(Ovl)) {
8389 // Only consider templates found within the same semantic lookup scope as
8391 if (!FDLookupContext->InEnclosingNamespaceSetOf(
8392 Ovl->getDeclContext()->getRedeclContext()))
8395 // When matching a constexpr member function template specialization
8396 // against the primary template, we don't yet know whether the
8397 // specialization has an implicit 'const' (because we don't know whether
8398 // it will be a static member function until we know which template it
8399 // specializes), so adjust it now assuming it specializes this template.
8400 QualType FT = FD->getType();
8401 if (FD->isConstexpr()) {
8402 CXXMethodDecl *OldMD =
8403 dyn_cast<CXXMethodDecl>(FunTmpl->getTemplatedDecl());
8404 if (OldMD && OldMD->isConst()) {
8405 const FunctionProtoType *FPT = FT->castAs<FunctionProtoType>();
8406 FunctionProtoType::ExtProtoInfo EPI = FPT->getExtProtoInfo();
8407 EPI.TypeQuals.addConst();
8408 FT = Context.getFunctionType(FPT->getReturnType(),
8409 FPT->getParamTypes(), EPI);
8413 TemplateArgumentListInfo Args;
8414 if (ExplicitTemplateArgs)
8415 Args = *ExplicitTemplateArgs;
8417 // C++ [temp.expl.spec]p11:
8418 // A trailing template-argument can be left unspecified in the
8419 // template-id naming an explicit function template specialization
8420 // provided it can be deduced from the function argument type.
8421 // Perform template argument deduction to determine whether we may be
8422 // specializing this template.
8423 // FIXME: It is somewhat wasteful to build
8424 TemplateDeductionInfo Info(FailedCandidates.getLocation());
8425 FunctionDecl *Specialization = nullptr;
8426 if (TemplateDeductionResult TDK = DeduceTemplateArguments(
8427 cast<FunctionTemplateDecl>(FunTmpl->getFirstDecl()),
8428 ExplicitTemplateArgs ? &Args : nullptr, FT, Specialization,
8430 // Template argument deduction failed; record why it failed, so
8431 // that we can provide nifty diagnostics.
8432 FailedCandidates.addCandidate().set(
8433 I.getPair(), FunTmpl->getTemplatedDecl(),
8434 MakeDeductionFailureInfo(Context, TDK, Info));
8439 // Target attributes are part of the cuda function signature, so
8440 // the deduced template's cuda target must match that of the
8441 // specialization. Given that C++ template deduction does not
8442 // take target attributes into account, we reject candidates
8443 // here that have a different target.
8444 if (LangOpts.CUDA &&
8445 IdentifyCUDATarget(Specialization,
8446 /* IgnoreImplicitHDAttr = */ true) !=
8447 IdentifyCUDATarget(FD, /* IgnoreImplicitHDAttr = */ true)) {
8448 FailedCandidates.addCandidate().set(
8449 I.getPair(), FunTmpl->getTemplatedDecl(),
8450 MakeDeductionFailureInfo(Context, TDK_CUDATargetMismatch, Info));
8454 // Record this candidate.
8455 if (ExplicitTemplateArgs)
8456 ConvertedTemplateArgs[Specialization] = std::move(Args);
8457 Candidates.addDecl(Specialization, I.getAccess());
8461 // For a qualified friend declaration (with no explicit marker to indicate
8462 // that a template specialization was intended), note all (template and
8463 // non-template) candidates.
8464 if (QualifiedFriend && Candidates.empty()) {
8465 Diag(FD->getLocation(), diag::err_qualified_friend_no_match)
8466 << FD->getDeclName() << FDLookupContext;
8467 // FIXME: We should form a single candidate list and diagnose all
8468 // candidates at once, to get proper sorting and limiting.
8469 for (auto *OldND : Previous) {
8470 if (auto *OldFD = dyn_cast<FunctionDecl>(OldND->getUnderlyingDecl()))
8471 NoteOverloadCandidate(OldND, OldFD, FD->getType(), false);
8473 FailedCandidates.NoteCandidates(*this, FD->getLocation());
8477 // Find the most specialized function template.
8478 UnresolvedSetIterator Result = getMostSpecialized(
8479 Candidates.begin(), Candidates.end(), FailedCandidates, FD->getLocation(),
8480 PDiag(diag::err_function_template_spec_no_match) << FD->getDeclName(),
8481 PDiag(diag::err_function_template_spec_ambiguous)
8482 << FD->getDeclName() << (ExplicitTemplateArgs != nullptr),
8483 PDiag(diag::note_function_template_spec_matched));
8485 if (Result == Candidates.end())
8488 // Ignore access information; it doesn't figure into redeclaration checking.
8489 FunctionDecl *Specialization = cast<FunctionDecl>(*Result);
8491 FunctionTemplateSpecializationInfo *SpecInfo
8492 = Specialization->getTemplateSpecializationInfo();
8493 assert(SpecInfo && "Function template specialization info missing?");
8495 // Note: do not overwrite location info if previous template
8496 // specialization kind was explicit.
8497 TemplateSpecializationKind TSK = SpecInfo->getTemplateSpecializationKind();
8498 if (TSK == TSK_Undeclared || TSK == TSK_ImplicitInstantiation) {
8499 Specialization->setLocation(FD->getLocation());
8500 Specialization->setLexicalDeclContext(FD->getLexicalDeclContext());
8501 // C++11 [dcl.constexpr]p1: An explicit specialization of a constexpr
8502 // function can differ from the template declaration with respect to
8503 // the constexpr specifier.
8504 // FIXME: We need an update record for this AST mutation.
8505 // FIXME: What if there are multiple such prior declarations (for instance,
8506 // from different modules)?
8507 Specialization->setConstexprKind(FD->getConstexprKind());
8510 // FIXME: Check if the prior specialization has a point of instantiation.
8511 // If so, we have run afoul of .
8513 // If this is a friend declaration, then we're not really declaring
8514 // an explicit specialization.
8515 bool isFriend = (FD->getFriendObjectKind() != Decl::FOK_None);
8517 // Check the scope of this explicit specialization.
8519 CheckTemplateSpecializationScope(*this,
8520 Specialization->getPrimaryTemplate(),
8521 Specialization, FD->getLocation(),
8525 // C++ [temp.expl.spec]p6:
8526 // If a template, a member template or the member of a class template is
8527 // explicitly specialized then that specialization shall be declared
8528 // before the first use of that specialization that would cause an implicit
8529 // instantiation to take place, in every translation unit in which such a
8530 // use occurs; no diagnostic is required.
8531 bool HasNoEffect = false;
8533 CheckSpecializationInstantiationRedecl(FD->getLocation(),
8534 TSK_ExplicitSpecialization,
8536 SpecInfo->getTemplateSpecializationKind(),
8537 SpecInfo->getPointOfInstantiation(),
8541 // Mark the prior declaration as an explicit specialization, so that later
8542 // clients know that this is an explicit specialization.
8544 // Since explicit specializations do not inherit '=delete' from their
8545 // primary function template - check if the 'specialization' that was
8546 // implicitly generated (during template argument deduction for partial
8547 // ordering) from the most specialized of all the function templates that
8548 // 'FD' could have been specializing, has a 'deleted' definition. If so,
8549 // first check that it was implicitly generated during template argument
8550 // deduction by making sure it wasn't referenced, and then reset the deleted
8551 // flag to not-deleted, so that we can inherit that information from 'FD'.
8552 if (Specialization->isDeleted() && !SpecInfo->isExplicitSpecialization() &&
8553 !Specialization->getCanonicalDecl()->isReferenced()) {
8554 // FIXME: This assert will not hold in the presence of modules.
8556 Specialization->getCanonicalDecl() == Specialization &&
8557 "This must be the only existing declaration of this specialization");
8558 // FIXME: We need an update record for this AST mutation.
8559 Specialization->setDeletedAsWritten(false);
8561 // FIXME: We need an update record for this AST mutation.
8562 SpecInfo->setTemplateSpecializationKind(TSK_ExplicitSpecialization);
8563 MarkUnusedFileScopedDecl(Specialization);
8566 // Turn the given function declaration into a function template
8567 // specialization, with the template arguments from the previous
8569 // Take copies of (semantic and syntactic) template argument lists.
8570 const TemplateArgumentList* TemplArgs = new (Context)
8571 TemplateArgumentList(Specialization->getTemplateSpecializationArgs());
8572 FD->setFunctionTemplateSpecialization(
8573 Specialization->getPrimaryTemplate(), TemplArgs, /*InsertPos=*/nullptr,
8574 SpecInfo->getTemplateSpecializationKind(),
8575 ExplicitTemplateArgs ? &ConvertedTemplateArgs[Specialization] : nullptr);
8577 // A function template specialization inherits the target attributes
8578 // of its template. (We require the attributes explicitly in the
8579 // code to match, but a template may have implicit attributes by
8580 // virtue e.g. of being constexpr, and it passes these implicit
8581 // attributes on to its specializations.)
8583 inheritCUDATargetAttrs(FD, *Specialization->getPrimaryTemplate());
8585 // The "previous declaration" for this function template specialization is
8586 // the prior function template specialization.
8588 Previous.addDecl(Specialization);
8592 /// Perform semantic analysis for the given non-template member
8595 /// This routine performs all of the semantic analysis required for an
8596 /// explicit member function specialization. On successful completion,
8597 /// the function declaration \p FD will become a member function
8600 /// \param Member the member declaration, which will be updated to become a
8603 /// \param Previous the set of declarations, one of which may be specialized
8604 /// by this function specialization; the set will be modified to contain the
8605 /// redeclared member.
8607 Sema::CheckMemberSpecialization(NamedDecl *Member, LookupResult &Previous) {
8608 assert(!isa<TemplateDecl>(Member) && "Only for non-template members");
8610 // Try to find the member we are instantiating.
8611 NamedDecl *FoundInstantiation = nullptr;
8612 NamedDecl *Instantiation = nullptr;
8613 NamedDecl *InstantiatedFrom = nullptr;
8614 MemberSpecializationInfo *MSInfo = nullptr;
8616 if (Previous.empty()) {
8617 // Nowhere to look anyway.
8618 } else if (FunctionDecl *Function = dyn_cast<FunctionDecl>(Member)) {
8619 for (LookupResult::iterator I = Previous.begin(), E = Previous.end();
8621 NamedDecl *D = (*I)->getUnderlyingDecl();
8622 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(D)) {
8623 QualType Adjusted = Function->getType();
8624 if (!hasExplicitCallingConv(Adjusted))
8625 Adjusted = adjustCCAndNoReturn(Adjusted, Method->getType());
8626 // This doesn't handle deduced return types, but both function
8627 // declarations should be undeduced at this point.
8628 if (Context.hasSameType(Adjusted, Method->getType())) {
8629 FoundInstantiation = *I;
8630 Instantiation = Method;
8631 InstantiatedFrom = Method->getInstantiatedFromMemberFunction();
8632 MSInfo = Method->getMemberSpecializationInfo();
8637 } else if (isa<VarDecl>(Member)) {
8639 if (Previous.isSingleResult() &&
8640 (PrevVar = dyn_cast<VarDecl>(Previous.getFoundDecl())))
8641 if (PrevVar->isStaticDataMember()) {
8642 FoundInstantiation = Previous.getRepresentativeDecl();
8643 Instantiation = PrevVar;
8644 InstantiatedFrom = PrevVar->getInstantiatedFromStaticDataMember();
8645 MSInfo = PrevVar->getMemberSpecializationInfo();
8647 } else if (isa<RecordDecl>(Member)) {
8648 CXXRecordDecl *PrevRecord;
8649 if (Previous.isSingleResult() &&
8650 (PrevRecord = dyn_cast<CXXRecordDecl>(Previous.getFoundDecl()))) {
8651 FoundInstantiation = Previous.getRepresentativeDecl();
8652 Instantiation = PrevRecord;
8653 InstantiatedFrom = PrevRecord->getInstantiatedFromMemberClass();
8654 MSInfo = PrevRecord->getMemberSpecializationInfo();
8656 } else if (isa<EnumDecl>(Member)) {
8658 if (Previous.isSingleResult() &&
8659 (PrevEnum = dyn_cast<EnumDecl>(Previous.getFoundDecl()))) {
8660 FoundInstantiation = Previous.getRepresentativeDecl();
8661 Instantiation = PrevEnum;
8662 InstantiatedFrom = PrevEnum->getInstantiatedFromMemberEnum();
8663 MSInfo = PrevEnum->getMemberSpecializationInfo();
8667 if (!Instantiation) {
8668 // There is no previous declaration that matches. Since member
8669 // specializations are always out-of-line, the caller will complain about
8670 // this mismatch later.
8674 // A member specialization in a friend declaration isn't really declaring
8675 // an explicit specialization, just identifying a specific (possibly implicit)
8676 // specialization. Don't change the template specialization kind.
8678 // FIXME: Is this really valid? Other compilers reject.
8679 if (Member->getFriendObjectKind() != Decl::FOK_None) {
8680 // Preserve instantiation information.
8681 if (InstantiatedFrom && isa<CXXMethodDecl>(Member)) {
8682 cast<CXXMethodDecl>(Member)->setInstantiationOfMemberFunction(
8683 cast<CXXMethodDecl>(InstantiatedFrom),
8684 cast<CXXMethodDecl>(Instantiation)->getTemplateSpecializationKind());
8685 } else if (InstantiatedFrom && isa<CXXRecordDecl>(Member)) {
8686 cast<CXXRecordDecl>(Member)->setInstantiationOfMemberClass(
8687 cast<CXXRecordDecl>(InstantiatedFrom),
8688 cast<CXXRecordDecl>(Instantiation)->getTemplateSpecializationKind());
8692 Previous.addDecl(FoundInstantiation);
8696 // Make sure that this is a specialization of a member.
8697 if (!InstantiatedFrom) {
8698 Diag(Member->getLocation(), diag::err_spec_member_not_instantiated)
8700 Diag(Instantiation->getLocation(), diag::note_specialized_decl);
8704 // C++ [temp.expl.spec]p6:
8705 // If a template, a member template or the member of a class template is
8706 // explicitly specialized then that specialization shall be declared
8707 // before the first use of that specialization that would cause an implicit
8708 // instantiation to take place, in every translation unit in which such a
8709 // use occurs; no diagnostic is required.
8710 assert(MSInfo && "Member specialization info missing?");
8712 bool HasNoEffect = false;
8713 if (CheckSpecializationInstantiationRedecl(Member->getLocation(),
8714 TSK_ExplicitSpecialization,
8716 MSInfo->getTemplateSpecializationKind(),
8717 MSInfo->getPointOfInstantiation(),
8721 // Check the scope of this explicit specialization.
8722 if (CheckTemplateSpecializationScope(*this,
8724 Instantiation, Member->getLocation(),
8728 // Note that this member specialization is an "instantiation of" the
8729 // corresponding member of the original template.
8730 if (auto *MemberFunction = dyn_cast<FunctionDecl>(Member)) {
8731 FunctionDecl *InstantiationFunction = cast<FunctionDecl>(Instantiation);
8732 if (InstantiationFunction->getTemplateSpecializationKind() ==
8733 TSK_ImplicitInstantiation) {
8734 // Explicit specializations of member functions of class templates do not
8735 // inherit '=delete' from the member function they are specializing.
8736 if (InstantiationFunction->isDeleted()) {
8737 // FIXME: This assert will not hold in the presence of modules.
8738 assert(InstantiationFunction->getCanonicalDecl() ==
8739 InstantiationFunction);
8740 // FIXME: We need an update record for this AST mutation.
8741 InstantiationFunction->setDeletedAsWritten(false);
8745 MemberFunction->setInstantiationOfMemberFunction(
8746 cast<CXXMethodDecl>(InstantiatedFrom), TSK_ExplicitSpecialization);
8747 } else if (auto *MemberVar = dyn_cast<VarDecl>(Member)) {
8748 MemberVar->setInstantiationOfStaticDataMember(
8749 cast<VarDecl>(InstantiatedFrom), TSK_ExplicitSpecialization);
8750 } else if (auto *MemberClass = dyn_cast<CXXRecordDecl>(Member)) {
8751 MemberClass->setInstantiationOfMemberClass(
8752 cast<CXXRecordDecl>(InstantiatedFrom), TSK_ExplicitSpecialization);
8753 } else if (auto *MemberEnum = dyn_cast<EnumDecl>(Member)) {
8754 MemberEnum->setInstantiationOfMemberEnum(
8755 cast<EnumDecl>(InstantiatedFrom), TSK_ExplicitSpecialization);
8757 llvm_unreachable("unknown member specialization kind");
8760 // Save the caller the trouble of having to figure out which declaration
8761 // this specialization matches.
8763 Previous.addDecl(FoundInstantiation);
8767 /// Complete the explicit specialization of a member of a class template by
8768 /// updating the instantiated member to be marked as an explicit specialization.
8770 /// \param OrigD The member declaration instantiated from the template.
8771 /// \param Loc The location of the explicit specialization of the member.
8772 template<typename DeclT>
8773 static void completeMemberSpecializationImpl(Sema &S, DeclT *OrigD,
8774 SourceLocation Loc) {
8775 if (OrigD->getTemplateSpecializationKind() != TSK_ImplicitInstantiation)
8778 // FIXME: Inform AST mutation listeners of this AST mutation.
8779 // FIXME: If there are multiple in-class declarations of the member (from
8780 // multiple modules, or a declaration and later definition of a member type),
8781 // should we update all of them?
8782 OrigD->setTemplateSpecializationKind(TSK_ExplicitSpecialization);
8783 OrigD->setLocation(Loc);
8786 void Sema::CompleteMemberSpecialization(NamedDecl *Member,
8787 LookupResult &Previous) {
8788 NamedDecl *Instantiation = cast<NamedDecl>(Member->getCanonicalDecl());
8789 if (Instantiation == Member)
8792 if (auto *Function = dyn_cast<CXXMethodDecl>(Instantiation))
8793 completeMemberSpecializationImpl(*this, Function, Member->getLocation());
8794 else if (auto *Var = dyn_cast<VarDecl>(Instantiation))
8795 completeMemberSpecializationImpl(*this, Var, Member->getLocation());
8796 else if (auto *Record = dyn_cast<CXXRecordDecl>(Instantiation))
8797 completeMemberSpecializationImpl(*this, Record, Member->getLocation());
8798 else if (auto *Enum = dyn_cast<EnumDecl>(Instantiation))
8799 completeMemberSpecializationImpl(*this, Enum, Member->getLocation());
8801 llvm_unreachable("unknown member specialization kind");
8804 /// Check the scope of an explicit instantiation.
8806 /// \returns true if a serious error occurs, false otherwise.
8807 static bool CheckExplicitInstantiationScope(Sema &S, NamedDecl *D,
8808 SourceLocation InstLoc,
8809 bool WasQualifiedName) {
8810 DeclContext *OrigContext= D->getDeclContext()->getEnclosingNamespaceContext();
8811 DeclContext *CurContext = S.CurContext->getRedeclContext();
8813 if (CurContext->isRecord()) {
8814 S.Diag(InstLoc, diag::err_explicit_instantiation_in_class)
8819 // C++11 [temp.explicit]p3:
8820 // An explicit instantiation shall appear in an enclosing namespace of its
8821 // template. If the name declared in the explicit instantiation is an
8822 // unqualified name, the explicit instantiation shall appear in the
8823 // namespace where its template is declared or, if that namespace is inline
8824 // (7.3.1), any namespace from its enclosing namespace set.
8826 // This is DR275, which we do not retroactively apply to C++98/03.
8827 if (WasQualifiedName) {
8828 if (CurContext->Encloses(OrigContext))
8831 if (CurContext->InEnclosingNamespaceSetOf(OrigContext))
8835 if (NamespaceDecl *NS = dyn_cast<NamespaceDecl>(OrigContext)) {
8836 if (WasQualifiedName)
8838 S.getLangOpts().CPlusPlus11?
8839 diag::err_explicit_instantiation_out_of_scope :
8840 diag::warn_explicit_instantiation_out_of_scope_0x)
8844 S.getLangOpts().CPlusPlus11?
8845 diag::err_explicit_instantiation_unqualified_wrong_namespace :
8846 diag::warn_explicit_instantiation_unqualified_wrong_namespace_0x)
8850 S.getLangOpts().CPlusPlus11?
8851 diag::err_explicit_instantiation_must_be_global :
8852 diag::warn_explicit_instantiation_must_be_global_0x)
8854 S.Diag(D->getLocation(), diag::note_explicit_instantiation_here);
8858 /// Common checks for whether an explicit instantiation of \p D is valid.
8859 static bool CheckExplicitInstantiation(Sema &S, NamedDecl *D,
8860 SourceLocation InstLoc,
8861 bool WasQualifiedName,
8862 TemplateSpecializationKind TSK) {
8863 // C++ [temp.explicit]p13:
8864 // An explicit instantiation declaration shall not name a specialization of
8865 // a template with internal linkage.
8866 if (TSK == TSK_ExplicitInstantiationDeclaration &&
8867 D->getFormalLinkage() == InternalLinkage) {
8868 S.Diag(InstLoc, diag::err_explicit_instantiation_internal_linkage) << D;
8872 // C++11 [temp.explicit]p3: [DR 275]
8873 // An explicit instantiation shall appear in an enclosing namespace of its
8875 if (CheckExplicitInstantiationScope(S, D, InstLoc, WasQualifiedName))
8881 /// Determine whether the given scope specifier has a template-id in it.
8882 static bool ScopeSpecifierHasTemplateId(const CXXScopeSpec &SS) {
8886 // C++11 [temp.explicit]p3:
8887 // If the explicit instantiation is for a member function, a member class
8888 // or a static data member of a class template specialization, the name of
8889 // the class template specialization in the qualified-id for the member
8890 // name shall be a simple-template-id.
8892 // C++98 has the same restriction, just worded differently.
8893 for (NestedNameSpecifier *NNS = SS.getScopeRep(); NNS;
8894 NNS = NNS->getPrefix())
8895 if (const Type *T = NNS->getAsType())
8896 if (isa<TemplateSpecializationType>(T))
8902 /// Make a dllexport or dllimport attr on a class template specialization take
8904 static void dllExportImportClassTemplateSpecialization(
8905 Sema &S, ClassTemplateSpecializationDecl *Def) {
8906 auto *A = cast_or_null<InheritableAttr>(getDLLAttr(Def));
8907 assert(A && "dllExportImportClassTemplateSpecialization called "
8908 "on Def without dllexport or dllimport");
8910 // We reject explicit instantiations in class scope, so there should
8911 // never be any delayed exported classes to worry about.
8912 assert(S.DelayedDllExportClasses.empty() &&
8913 "delayed exports present at explicit instantiation");
8914 S.checkClassLevelDLLAttribute(Def);
8916 // Propagate attribute to base class templates.
8917 for (auto &B : Def->bases()) {
8918 if (auto *BT = dyn_cast_or_null<ClassTemplateSpecializationDecl>(
8919 B.getType()->getAsCXXRecordDecl()))
8920 S.propagateDLLAttrToBaseClassTemplate(Def, A, BT, B.getBeginLoc());
8923 S.referenceDLLExportedClassMethods();
8926 // Explicit instantiation of a class template specialization
8927 DeclResult Sema::ActOnExplicitInstantiation(
8928 Scope *S, SourceLocation ExternLoc, SourceLocation TemplateLoc,
8929 unsigned TagSpec, SourceLocation KWLoc, const CXXScopeSpec &SS,
8930 TemplateTy TemplateD, SourceLocation TemplateNameLoc,
8931 SourceLocation LAngleLoc, ASTTemplateArgsPtr TemplateArgsIn,
8932 SourceLocation RAngleLoc, const ParsedAttributesView &Attr) {
8933 // Find the class template we're specializing
8934 TemplateName Name = TemplateD.get();
8935 TemplateDecl *TD = Name.getAsTemplateDecl();
8936 // Check that the specialization uses the same tag kind as the
8937 // original template.
8938 TagTypeKind Kind = TypeWithKeyword::getTagTypeKindForTypeSpec(TagSpec);
8939 assert(Kind != TTK_Enum &&
8940 "Invalid enum tag in class template explicit instantiation!");
8942 ClassTemplateDecl *ClassTemplate = dyn_cast<ClassTemplateDecl>(TD);
8944 if (!ClassTemplate) {
8945 NonTagKind NTK = getNonTagTypeDeclKind(TD, Kind);
8946 Diag(TemplateNameLoc, diag::err_tag_reference_non_tag) << TD << NTK << Kind;
8947 Diag(TD->getLocation(), diag::note_previous_use);
8951 if (!isAcceptableTagRedeclaration(ClassTemplate->getTemplatedDecl(),
8952 Kind, /*isDefinition*/false, KWLoc,
8953 ClassTemplate->getIdentifier())) {
8954 Diag(KWLoc, diag::err_use_with_wrong_tag)
8956 << FixItHint::CreateReplacement(KWLoc,
8957 ClassTemplate->getTemplatedDecl()->getKindName());
8958 Diag(ClassTemplate->getTemplatedDecl()->getLocation(),
8959 diag::note_previous_use);
8960 Kind = ClassTemplate->getTemplatedDecl()->getTagKind();
8963 // C++0x [temp.explicit]p2:
8964 // There are two forms of explicit instantiation: an explicit instantiation
8965 // definition and an explicit instantiation declaration. An explicit
8966 // instantiation declaration begins with the extern keyword. [...]
8967 TemplateSpecializationKind TSK = ExternLoc.isInvalid()
8968 ? TSK_ExplicitInstantiationDefinition
8969 : TSK_ExplicitInstantiationDeclaration;
8971 if (TSK == TSK_ExplicitInstantiationDeclaration &&
8972 !Context.getTargetInfo().getTriple().isWindowsGNUEnvironment()) {
8973 // Check for dllexport class template instantiation declarations,
8974 // except for MinGW mode.
8975 for (const ParsedAttr &AL : Attr) {
8976 if (AL.getKind() == ParsedAttr::AT_DLLExport) {
8978 diag::warn_attribute_dllexport_explicit_instantiation_decl);
8979 Diag(AL.getLoc(), diag::note_attribute);
8984 if (auto *A = ClassTemplate->getTemplatedDecl()->getAttr<DLLExportAttr>()) {
8986 diag::warn_attribute_dllexport_explicit_instantiation_decl);
8987 Diag(A->getLocation(), diag::note_attribute);
8991 // In MSVC mode, dllimported explicit instantiation definitions are treated as
8992 // instantiation declarations for most purposes.
8993 bool DLLImportExplicitInstantiationDef = false;
8994 if (TSK == TSK_ExplicitInstantiationDefinition &&
8995 Context.getTargetInfo().getCXXABI().isMicrosoft()) {
8996 // Check for dllimport class template instantiation definitions.
8998 ClassTemplate->getTemplatedDecl()->getAttr<DLLImportAttr>();
8999 for (const ParsedAttr &AL : Attr) {
9000 if (AL.getKind() == ParsedAttr::AT_DLLImport)
9002 if (AL.getKind() == ParsedAttr::AT_DLLExport) {
9003 // dllexport trumps dllimport here.
9009 TSK = TSK_ExplicitInstantiationDeclaration;
9010 DLLImportExplicitInstantiationDef = true;
9014 // Translate the parser's template argument list in our AST format.
9015 TemplateArgumentListInfo TemplateArgs(LAngleLoc, RAngleLoc);
9016 translateTemplateArguments(TemplateArgsIn, TemplateArgs);
9018 // Check that the template argument list is well-formed for this
9020 SmallVector<TemplateArgument, 4> Converted;
9021 if (CheckTemplateArgumentList(ClassTemplate, TemplateNameLoc,
9022 TemplateArgs, false, Converted))
9025 // Find the class template specialization declaration that
9026 // corresponds to these arguments.
9027 void *InsertPos = nullptr;
9028 ClassTemplateSpecializationDecl *PrevDecl
9029 = ClassTemplate->findSpecialization(Converted, InsertPos);
9031 TemplateSpecializationKind PrevDecl_TSK
9032 = PrevDecl ? PrevDecl->getTemplateSpecializationKind() : TSK_Undeclared;
9034 if (TSK == TSK_ExplicitInstantiationDefinition && PrevDecl != nullptr &&
9035 Context.getTargetInfo().getTriple().isWindowsGNUEnvironment()) {
9036 // Check for dllexport class template instantiation definitions in MinGW
9037 // mode, if a previous declaration of the instantiation was seen.
9038 for (const ParsedAttr &AL : Attr) {
9039 if (AL.getKind() == ParsedAttr::AT_DLLExport) {
9041 diag::warn_attribute_dllexport_explicit_instantiation_def);
9047 if (CheckExplicitInstantiation(*this, ClassTemplate, TemplateNameLoc,
9051 ClassTemplateSpecializationDecl *Specialization = nullptr;
9053 bool HasNoEffect = false;
9055 if (CheckSpecializationInstantiationRedecl(TemplateNameLoc, TSK,
9056 PrevDecl, PrevDecl_TSK,
9057 PrevDecl->getPointOfInstantiation(),
9061 // Even though HasNoEffect == true means that this explicit instantiation
9062 // has no effect on semantics, we go on to put its syntax in the AST.
9064 if (PrevDecl_TSK == TSK_ImplicitInstantiation ||
9065 PrevDecl_TSK == TSK_Undeclared) {
9066 // Since the only prior class template specialization with these
9067 // arguments was referenced but not declared, reuse that
9068 // declaration node as our own, updating the source location
9069 // for the template name to reflect our new declaration.
9070 // (Other source locations will be updated later.)
9071 Specialization = PrevDecl;
9072 Specialization->setLocation(TemplateNameLoc);
9076 if (PrevDecl_TSK == TSK_ExplicitInstantiationDeclaration &&
9077 DLLImportExplicitInstantiationDef) {
9078 // The new specialization might add a dllimport attribute.
9079 HasNoEffect = false;
9083 if (!Specialization) {
9084 // Create a new class template specialization declaration node for
9085 // this explicit specialization.
9087 = ClassTemplateSpecializationDecl::Create(Context, Kind,
9088 ClassTemplate->getDeclContext(),
9089 KWLoc, TemplateNameLoc,
9093 SetNestedNameSpecifier(*this, Specialization, SS);
9095 if (!HasNoEffect && !PrevDecl) {
9096 // Insert the new specialization.
9097 ClassTemplate->AddSpecialization(Specialization, InsertPos);
9101 // Build the fully-sugared type for this explicit instantiation as
9102 // the user wrote in the explicit instantiation itself. This means
9103 // that we'll pretty-print the type retrieved from the
9104 // specialization's declaration the way that the user actually wrote
9105 // the explicit instantiation, rather than formatting the name based
9106 // on the "canonical" representation used to store the template
9107 // arguments in the specialization.
9108 TypeSourceInfo *WrittenTy
9109 = Context.getTemplateSpecializationTypeInfo(Name, TemplateNameLoc,
9111 Context.getTypeDeclType(Specialization));
9112 Specialization->setTypeAsWritten(WrittenTy);
9114 // Set source locations for keywords.
9115 Specialization->setExternLoc(ExternLoc);
9116 Specialization->setTemplateKeywordLoc(TemplateLoc);
9117 Specialization->setBraceRange(SourceRange());
9119 bool PreviouslyDLLExported = Specialization->hasAttr<DLLExportAttr>();
9120 ProcessDeclAttributeList(S, Specialization, Attr);
9122 // Add the explicit instantiation into its lexical context. However,
9123 // since explicit instantiations are never found by name lookup, we
9124 // just put it into the declaration context directly.
9125 Specialization->setLexicalDeclContext(CurContext);
9126 CurContext->addDecl(Specialization);
9128 // Syntax is now OK, so return if it has no other effect on semantics.
9130 // Set the template specialization kind.
9131 Specialization->setTemplateSpecializationKind(TSK);
9132 return Specialization;
9135 // C++ [temp.explicit]p3:
9136 // A definition of a class template or class member template
9137 // shall be in scope at the point of the explicit instantiation of
9138 // the class template or class member template.
9140 // This check comes when we actually try to perform the
9142 ClassTemplateSpecializationDecl *Def
9143 = cast_or_null<ClassTemplateSpecializationDecl>(
9144 Specialization->getDefinition());
9146 InstantiateClassTemplateSpecialization(TemplateNameLoc, Specialization, TSK);
9147 else if (TSK == TSK_ExplicitInstantiationDefinition) {
9148 MarkVTableUsed(TemplateNameLoc, Specialization, true);
9149 Specialization->setPointOfInstantiation(Def->getPointOfInstantiation());
9152 // Instantiate the members of this class template specialization.
9153 Def = cast_or_null<ClassTemplateSpecializationDecl>(
9154 Specialization->getDefinition());
9156 TemplateSpecializationKind Old_TSK = Def->getTemplateSpecializationKind();
9157 // Fix a TSK_ExplicitInstantiationDeclaration followed by a
9158 // TSK_ExplicitInstantiationDefinition
9159 if (Old_TSK == TSK_ExplicitInstantiationDeclaration &&
9160 (TSK == TSK_ExplicitInstantiationDefinition ||
9161 DLLImportExplicitInstantiationDef)) {
9162 // FIXME: Need to notify the ASTMutationListener that we did this.
9163 Def->setTemplateSpecializationKind(TSK);
9165 if (!getDLLAttr(Def) && getDLLAttr(Specialization) &&
9166 (Context.getTargetInfo().getCXXABI().isMicrosoft() ||
9167 Context.getTargetInfo().getTriple().isWindowsItaniumEnvironment())) {
9168 // In the MS ABI, an explicit instantiation definition can add a dll
9169 // attribute to a template with a previous instantiation declaration.
9170 // MinGW doesn't allow this.
9171 auto *A = cast<InheritableAttr>(
9172 getDLLAttr(Specialization)->clone(getASTContext()));
9173 A->setInherited(true);
9175 dllExportImportClassTemplateSpecialization(*this, Def);
9179 // Fix a TSK_ImplicitInstantiation followed by a
9180 // TSK_ExplicitInstantiationDefinition
9181 bool NewlyDLLExported =
9182 !PreviouslyDLLExported && Specialization->hasAttr<DLLExportAttr>();
9183 if (Old_TSK == TSK_ImplicitInstantiation && NewlyDLLExported &&
9184 (Context.getTargetInfo().getCXXABI().isMicrosoft() ||
9185 Context.getTargetInfo().getTriple().isWindowsItaniumEnvironment())) {
9186 // In the MS ABI, an explicit instantiation definition can add a dll
9187 // attribute to a template with a previous implicit instantiation.
9188 // MinGW doesn't allow this. We limit clang to only adding dllexport, to
9189 // avoid potentially strange codegen behavior. For example, if we extend
9190 // this conditional to dllimport, and we have a source file calling a
9191 // method on an implicitly instantiated template class instance and then
9192 // declaring a dllimport explicit instantiation definition for the same
9193 // template class, the codegen for the method call will not respect the
9194 // dllimport, while it will with cl. The Def will already have the DLL
9195 // attribute, since the Def and Specialization will be the same in the
9196 // case of Old_TSK == TSK_ImplicitInstantiation, and we already added the
9197 // attribute to the Specialization; we just need to make it take effect.
9198 assert(Def == Specialization &&
9199 "Def and Specialization should match for implicit instantiation");
9200 dllExportImportClassTemplateSpecialization(*this, Def);
9203 // In MinGW mode, export the template instantiation if the declaration
9204 // was marked dllexport.
9205 if (PrevDecl_TSK == TSK_ExplicitInstantiationDeclaration &&
9206 Context.getTargetInfo().getTriple().isWindowsGNUEnvironment() &&
9207 PrevDecl->hasAttr<DLLExportAttr>()) {
9208 dllExportImportClassTemplateSpecialization(*this, Def);
9211 // Set the template specialization kind. Make sure it is set before
9212 // instantiating the members which will trigger ASTConsumer callbacks.
9213 Specialization->setTemplateSpecializationKind(TSK);
9214 InstantiateClassTemplateSpecializationMembers(TemplateNameLoc, Def, TSK);
9217 // Set the template specialization kind.
9218 Specialization->setTemplateSpecializationKind(TSK);
9221 return Specialization;
9224 // Explicit instantiation of a member class of a class template.
9226 Sema::ActOnExplicitInstantiation(Scope *S, SourceLocation ExternLoc,
9227 SourceLocation TemplateLoc, unsigned TagSpec,
9228 SourceLocation KWLoc, CXXScopeSpec &SS,
9229 IdentifierInfo *Name, SourceLocation NameLoc,
9230 const ParsedAttributesView &Attr) {
9233 bool IsDependent = false;
9234 Decl *TagD = ActOnTag(S, TagSpec, Sema::TUK_Reference,
9235 KWLoc, SS, Name, NameLoc, Attr, AS_none,
9236 /*ModulePrivateLoc=*/SourceLocation(),
9237 MultiTemplateParamsArg(), Owned, IsDependent,
9238 SourceLocation(), false, TypeResult(),
9239 /*IsTypeSpecifier*/false,
9240 /*IsTemplateParamOrArg*/false);
9241 assert(!IsDependent && "explicit instantiation of dependent name not yet handled");
9246 TagDecl *Tag = cast<TagDecl>(TagD);
9247 assert(!Tag->isEnum() && "shouldn't see enumerations here");
9249 if (Tag->isInvalidDecl())
9252 CXXRecordDecl *Record = cast<CXXRecordDecl>(Tag);
9253 CXXRecordDecl *Pattern = Record->getInstantiatedFromMemberClass();
9255 Diag(TemplateLoc, diag::err_explicit_instantiation_nontemplate_type)
9256 << Context.getTypeDeclType(Record);
9257 Diag(Record->getLocation(), diag::note_nontemplate_decl_here);
9261 // C++0x [temp.explicit]p2:
9262 // If the explicit instantiation is for a class or member class, the
9263 // elaborated-type-specifier in the declaration shall include a
9264 // simple-template-id.
9266 // C++98 has the same restriction, just worded differently.
9267 if (!ScopeSpecifierHasTemplateId(SS))
9268 Diag(TemplateLoc, diag::ext_explicit_instantiation_without_qualified_id)
9269 << Record << SS.getRange();
9271 // C++0x [temp.explicit]p2:
9272 // There are two forms of explicit instantiation: an explicit instantiation
9273 // definition and an explicit instantiation declaration. An explicit
9274 // instantiation declaration begins with the extern keyword. [...]
9275 TemplateSpecializationKind TSK
9276 = ExternLoc.isInvalid()? TSK_ExplicitInstantiationDefinition
9277 : TSK_ExplicitInstantiationDeclaration;
9279 CheckExplicitInstantiation(*this, Record, NameLoc, true, TSK);
9281 // Verify that it is okay to explicitly instantiate here.
9282 CXXRecordDecl *PrevDecl
9283 = cast_or_null<CXXRecordDecl>(Record->getPreviousDecl());
9284 if (!PrevDecl && Record->getDefinition())
9287 MemberSpecializationInfo *MSInfo = PrevDecl->getMemberSpecializationInfo();
9288 bool HasNoEffect = false;
9289 assert(MSInfo && "No member specialization information?");
9290 if (CheckSpecializationInstantiationRedecl(TemplateLoc, TSK,
9292 MSInfo->getTemplateSpecializationKind(),
9293 MSInfo->getPointOfInstantiation(),
9300 CXXRecordDecl *RecordDef
9301 = cast_or_null<CXXRecordDecl>(Record->getDefinition());
9303 // C++ [temp.explicit]p3:
9304 // A definition of a member class of a class template shall be in scope
9305 // at the point of an explicit instantiation of the member class.
9307 = cast_or_null<CXXRecordDecl>(Pattern->getDefinition());
9309 Diag(TemplateLoc, diag::err_explicit_instantiation_undefined_member)
9310 << 0 << Record->getDeclName() << Record->getDeclContext();
9311 Diag(Pattern->getLocation(), diag::note_forward_declaration)
9315 if (InstantiateClass(NameLoc, Record, Def,
9316 getTemplateInstantiationArgs(Record),
9320 RecordDef = cast_or_null<CXXRecordDecl>(Record->getDefinition());
9326 // Instantiate all of the members of the class.
9327 InstantiateClassMembers(NameLoc, RecordDef,
9328 getTemplateInstantiationArgs(Record), TSK);
9330 if (TSK == TSK_ExplicitInstantiationDefinition)
9331 MarkVTableUsed(NameLoc, RecordDef, true);
9333 // FIXME: We don't have any representation for explicit instantiations of
9334 // member classes. Such a representation is not needed for compilation, but it
9335 // should be available for clients that want to see all of the declarations in
9340 DeclResult Sema::ActOnExplicitInstantiation(Scope *S,
9341 SourceLocation ExternLoc,
9342 SourceLocation TemplateLoc,
9344 // Explicit instantiations always require a name.
9345 // TODO: check if/when DNInfo should replace Name.
9346 DeclarationNameInfo NameInfo = GetNameForDeclarator(D);
9347 DeclarationName Name = NameInfo.getName();
9349 if (!D.isInvalidType())
9350 Diag(D.getDeclSpec().getBeginLoc(),
9351 diag::err_explicit_instantiation_requires_name)
9352 << D.getDeclSpec().getSourceRange() << D.getSourceRange();
9357 // The scope passed in may not be a decl scope. Zip up the scope tree until
9358 // we find one that is.
9359 while ((S->getFlags() & Scope::DeclScope) == 0 ||
9360 (S->getFlags() & Scope::TemplateParamScope) != 0)
9363 // Determine the type of the declaration.
9364 TypeSourceInfo *T = GetTypeForDeclarator(D, S);
9365 QualType R = T->getType();
9370 // A storage-class-specifier shall not be specified in [...] an explicit
9371 // instantiation (14.7.2) directive.
9372 if (D.getDeclSpec().getStorageClassSpec() == DeclSpec::SCS_typedef) {
9373 Diag(D.getIdentifierLoc(), diag::err_explicit_instantiation_of_typedef)
9376 } else if (D.getDeclSpec().getStorageClassSpec()
9377 != DeclSpec::SCS_unspecified) {
9378 // Complain about then remove the storage class specifier.
9379 Diag(D.getIdentifierLoc(), diag::err_explicit_instantiation_storage_class)
9380 << FixItHint::CreateRemoval(D.getDeclSpec().getStorageClassSpecLoc());
9382 D.getMutableDeclSpec().ClearStorageClassSpecs();
9385 // C++0x [temp.explicit]p1:
9386 // [...] An explicit instantiation of a function template shall not use the
9387 // inline or constexpr specifiers.
9388 // Presumably, this also applies to member functions of class templates as
9390 if (D.getDeclSpec().isInlineSpecified())
9391 Diag(D.getDeclSpec().getInlineSpecLoc(),
9392 getLangOpts().CPlusPlus11 ?
9393 diag::err_explicit_instantiation_inline :
9394 diag::warn_explicit_instantiation_inline_0x)
9395 << FixItHint::CreateRemoval(D.getDeclSpec().getInlineSpecLoc());
9396 if (D.getDeclSpec().hasConstexprSpecifier() && R->isFunctionType())
9397 // FIXME: Add a fix-it to remove the 'constexpr' and add a 'const' if one is
9398 // not already specified.
9399 Diag(D.getDeclSpec().getConstexprSpecLoc(),
9400 diag::err_explicit_instantiation_constexpr);
9402 // A deduction guide is not on the list of entities that can be explicitly
9404 if (Name.getNameKind() == DeclarationName::CXXDeductionGuideName) {
9405 Diag(D.getDeclSpec().getBeginLoc(), diag::err_deduction_guide_specialized)
9406 << /*explicit instantiation*/ 0;
9410 // C++0x [temp.explicit]p2:
9411 // There are two forms of explicit instantiation: an explicit instantiation
9412 // definition and an explicit instantiation declaration. An explicit
9413 // instantiation declaration begins with the extern keyword. [...]
9414 TemplateSpecializationKind TSK
9415 = ExternLoc.isInvalid()? TSK_ExplicitInstantiationDefinition
9416 : TSK_ExplicitInstantiationDeclaration;
9418 LookupResult Previous(*this, NameInfo, LookupOrdinaryName);
9419 LookupParsedName(Previous, S, &D.getCXXScopeSpec());
9421 if (!R->isFunctionType()) {
9422 // C++ [temp.explicit]p1:
9423 // A [...] static data member of a class template can be explicitly
9424 // instantiated from the member definition associated with its class
9426 // C++1y [temp.explicit]p1:
9427 // A [...] variable [...] template specialization can be explicitly
9428 // instantiated from its template.
9429 if (Previous.isAmbiguous())
9432 VarDecl *Prev = Previous.getAsSingle<VarDecl>();
9433 VarTemplateDecl *PrevTemplate = Previous.getAsSingle<VarTemplateDecl>();
9435 if (!PrevTemplate) {
9436 if (!Prev || !Prev->isStaticDataMember()) {
9437 // We expect to see a static data member here.
9438 Diag(D.getIdentifierLoc(), diag::err_explicit_instantiation_not_known)
9440 for (LookupResult::iterator P = Previous.begin(), PEnd = Previous.end();
9442 Diag((*P)->getLocation(), diag::note_explicit_instantiation_here);
9446 if (!Prev->getInstantiatedFromStaticDataMember()) {
9447 // FIXME: Check for explicit specialization?
9448 Diag(D.getIdentifierLoc(),
9449 diag::err_explicit_instantiation_data_member_not_instantiated)
9451 Diag(Prev->getLocation(), diag::note_explicit_instantiation_here);
9452 // FIXME: Can we provide a note showing where this was declared?
9456 // Explicitly instantiate a variable template.
9458 // C++1y [dcl.spec.auto]p6:
9459 // ... A program that uses auto or decltype(auto) in a context not
9460 // explicitly allowed in this section is ill-formed.
9462 // This includes auto-typed variable template instantiations.
9463 if (R->isUndeducedType()) {
9464 Diag(T->getTypeLoc().getBeginLoc(),
9465 diag::err_auto_not_allowed_var_inst);
9469 if (D.getName().getKind() != UnqualifiedIdKind::IK_TemplateId) {
9470 // C++1y [temp.explicit]p3:
9471 // If the explicit instantiation is for a variable, the unqualified-id
9472 // in the declaration shall be a template-id.
9473 Diag(D.getIdentifierLoc(),
9474 diag::err_explicit_instantiation_without_template_id)
9476 Diag(PrevTemplate->getLocation(),
9477 diag::note_explicit_instantiation_here);
9481 // Translate the parser's template argument list into our AST format.
9482 TemplateArgumentListInfo TemplateArgs =
9483 makeTemplateArgumentListInfo(*this, *D.getName().TemplateId);
9485 DeclResult Res = CheckVarTemplateId(PrevTemplate, TemplateLoc,
9486 D.getIdentifierLoc(), TemplateArgs);
9487 if (Res.isInvalid())
9490 // Ignore access control bits, we don't need them for redeclaration
9492 Prev = cast<VarDecl>(Res.get());
9495 // C++0x [temp.explicit]p2:
9496 // If the explicit instantiation is for a member function, a member class
9497 // or a static data member of a class template specialization, the name of
9498 // the class template specialization in the qualified-id for the member
9499 // name shall be a simple-template-id.
9501 // C++98 has the same restriction, just worded differently.
9503 // This does not apply to variable template specializations, where the
9504 // template-id is in the unqualified-id instead.
9505 if (!ScopeSpecifierHasTemplateId(D.getCXXScopeSpec()) && !PrevTemplate)
9506 Diag(D.getIdentifierLoc(),
9507 diag::ext_explicit_instantiation_without_qualified_id)
9508 << Prev << D.getCXXScopeSpec().getRange();
9510 CheckExplicitInstantiation(*this, Prev, D.getIdentifierLoc(), true, TSK);
9512 // Verify that it is okay to explicitly instantiate here.
9513 TemplateSpecializationKind PrevTSK = Prev->getTemplateSpecializationKind();
9514 SourceLocation POI = Prev->getPointOfInstantiation();
9515 bool HasNoEffect = false;
9516 if (CheckSpecializationInstantiationRedecl(D.getIdentifierLoc(), TSK, Prev,
9517 PrevTSK, POI, HasNoEffect))
9521 // Instantiate static data member or variable template.
9522 Prev->setTemplateSpecializationKind(TSK, D.getIdentifierLoc());
9523 // Merge attributes.
9524 ProcessDeclAttributeList(S, Prev, D.getDeclSpec().getAttributes());
9525 if (TSK == TSK_ExplicitInstantiationDefinition)
9526 InstantiateVariableDefinition(D.getIdentifierLoc(), Prev);
9529 // Check the new variable specialization against the parsed input.
9530 if (PrevTemplate && Prev && !Context.hasSameType(Prev->getType(), R)) {
9531 Diag(T->getTypeLoc().getBeginLoc(),
9532 diag::err_invalid_var_template_spec_type)
9533 << 0 << PrevTemplate << R << Prev->getType();
9534 Diag(PrevTemplate->getLocation(), diag::note_template_declared_here)
9535 << 2 << PrevTemplate->getDeclName();
9539 // FIXME: Create an ExplicitInstantiation node?
9540 return (Decl*) nullptr;
9543 // If the declarator is a template-id, translate the parser's template
9544 // argument list into our AST format.
9545 bool HasExplicitTemplateArgs = false;
9546 TemplateArgumentListInfo TemplateArgs;
9547 if (D.getName().getKind() == UnqualifiedIdKind::IK_TemplateId) {
9548 TemplateArgs = makeTemplateArgumentListInfo(*this, *D.getName().TemplateId);
9549 HasExplicitTemplateArgs = true;
9552 // C++ [temp.explicit]p1:
9553 // A [...] function [...] can be explicitly instantiated from its template.
9554 // A member function [...] of a class template can be explicitly
9555 // instantiated from the member definition associated with its class
9557 UnresolvedSet<8> TemplateMatches;
9558 FunctionDecl *NonTemplateMatch = nullptr;
9559 TemplateSpecCandidateSet FailedCandidates(D.getIdentifierLoc());
9560 for (LookupResult::iterator P = Previous.begin(), PEnd = Previous.end();
9562 NamedDecl *Prev = *P;
9563 if (!HasExplicitTemplateArgs) {
9564 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Prev)) {
9565 QualType Adjusted = adjustCCAndNoReturn(R, Method->getType(),
9566 /*AdjustExceptionSpec*/true);
9567 if (Context.hasSameUnqualifiedType(Method->getType(), Adjusted)) {
9568 if (Method->getPrimaryTemplate()) {
9569 TemplateMatches.addDecl(Method, P.getAccess());
9571 // FIXME: Can this assert ever happen? Needs a test.
9572 assert(!NonTemplateMatch && "Multiple NonTemplateMatches");
9573 NonTemplateMatch = Method;
9579 FunctionTemplateDecl *FunTmpl = dyn_cast<FunctionTemplateDecl>(Prev);
9583 TemplateDeductionInfo Info(FailedCandidates.getLocation());
9584 FunctionDecl *Specialization = nullptr;
9585 if (TemplateDeductionResult TDK
9586 = DeduceTemplateArguments(FunTmpl,
9587 (HasExplicitTemplateArgs ? &TemplateArgs
9589 R, Specialization, Info)) {
9590 // Keep track of almost-matches.
9591 FailedCandidates.addCandidate()
9592 .set(P.getPair(), FunTmpl->getTemplatedDecl(),
9593 MakeDeductionFailureInfo(Context, TDK, Info));
9598 // Target attributes are part of the cuda function signature, so
9599 // the cuda target of the instantiated function must match that of its
9600 // template. Given that C++ template deduction does not take
9601 // target attributes into account, we reject candidates here that
9602 // have a different target.
9603 if (LangOpts.CUDA &&
9604 IdentifyCUDATarget(Specialization,
9605 /* IgnoreImplicitHDAttr = */ true) !=
9606 IdentifyCUDATarget(D.getDeclSpec().getAttributes())) {
9607 FailedCandidates.addCandidate().set(
9608 P.getPair(), FunTmpl->getTemplatedDecl(),
9609 MakeDeductionFailureInfo(Context, TDK_CUDATargetMismatch, Info));
9613 TemplateMatches.addDecl(Specialization, P.getAccess());
9616 FunctionDecl *Specialization = NonTemplateMatch;
9617 if (!Specialization) {
9618 // Find the most specialized function template specialization.
9619 UnresolvedSetIterator Result = getMostSpecialized(
9620 TemplateMatches.begin(), TemplateMatches.end(), FailedCandidates,
9621 D.getIdentifierLoc(),
9622 PDiag(diag::err_explicit_instantiation_not_known) << Name,
9623 PDiag(diag::err_explicit_instantiation_ambiguous) << Name,
9624 PDiag(diag::note_explicit_instantiation_candidate));
9626 if (Result == TemplateMatches.end())
9629 // Ignore access control bits, we don't need them for redeclaration checking.
9630 Specialization = cast<FunctionDecl>(*Result);
9633 // C++11 [except.spec]p4
9634 // In an explicit instantiation an exception-specification may be specified,
9635 // but is not required.
9636 // If an exception-specification is specified in an explicit instantiation
9637 // directive, it shall be compatible with the exception-specifications of
9638 // other declarations of that function.
9639 if (auto *FPT = R->getAs<FunctionProtoType>())
9640 if (FPT->hasExceptionSpec()) {
9642 diag::err_mismatched_exception_spec_explicit_instantiation;
9643 if (getLangOpts().MicrosoftExt)
9644 DiagID = diag::ext_mismatched_exception_spec_explicit_instantiation;
9645 bool Result = CheckEquivalentExceptionSpec(
9646 PDiag(DiagID) << Specialization->getType(),
9647 PDiag(diag::note_explicit_instantiation_here),
9648 Specialization->getType()->getAs<FunctionProtoType>(),
9649 Specialization->getLocation(), FPT, D.getBeginLoc());
9650 // In Microsoft mode, mismatching exception specifications just cause a
9652 if (!getLangOpts().MicrosoftExt && Result)
9656 if (Specialization->getTemplateSpecializationKind() == TSK_Undeclared) {
9657 Diag(D.getIdentifierLoc(),
9658 diag::err_explicit_instantiation_member_function_not_instantiated)
9660 << (Specialization->getTemplateSpecializationKind() ==
9661 TSK_ExplicitSpecialization);
9662 Diag(Specialization->getLocation(), diag::note_explicit_instantiation_here);
9666 FunctionDecl *PrevDecl = Specialization->getPreviousDecl();
9667 if (!PrevDecl && Specialization->isThisDeclarationADefinition())
9668 PrevDecl = Specialization;
9671 bool HasNoEffect = false;
9672 if (CheckSpecializationInstantiationRedecl(D.getIdentifierLoc(), TSK,
9674 PrevDecl->getTemplateSpecializationKind(),
9675 PrevDecl->getPointOfInstantiation(),
9679 // FIXME: We may still want to build some representation of this
9680 // explicit specialization.
9682 return (Decl*) nullptr;
9685 // HACK: libc++ has a bug where it attempts to explicitly instantiate the
9687 // valarray<size_t>::valarray(size_t) and
9688 // valarray<size_t>::~valarray()
9689 // that it declared to have internal linkage with the internal_linkage
9690 // attribute. Ignore the explicit instantiation declaration in this case.
9691 if (Specialization->hasAttr<InternalLinkageAttr>() &&
9692 TSK == TSK_ExplicitInstantiationDeclaration) {
9693 if (auto *RD = dyn_cast<CXXRecordDecl>(Specialization->getDeclContext()))
9694 if (RD->getIdentifier() && RD->getIdentifier()->isStr("valarray") &&
9695 RD->isInStdNamespace())
9696 return (Decl*) nullptr;
9699 ProcessDeclAttributeList(S, Specialization, D.getDeclSpec().getAttributes());
9701 // In MSVC mode, dllimported explicit instantiation definitions are treated as
9702 // instantiation declarations.
9703 if (TSK == TSK_ExplicitInstantiationDefinition &&
9704 Specialization->hasAttr<DLLImportAttr>() &&
9705 Context.getTargetInfo().getCXXABI().isMicrosoft())
9706 TSK = TSK_ExplicitInstantiationDeclaration;
9708 Specialization->setTemplateSpecializationKind(TSK, D.getIdentifierLoc());
9710 if (Specialization->isDefined()) {
9711 // Let the ASTConsumer know that this function has been explicitly
9712 // instantiated now, and its linkage might have changed.
9713 Consumer.HandleTopLevelDecl(DeclGroupRef(Specialization));
9714 } else if (TSK == TSK_ExplicitInstantiationDefinition)
9715 InstantiateFunctionDefinition(D.getIdentifierLoc(), Specialization);
9717 // C++0x [temp.explicit]p2:
9718 // If the explicit instantiation is for a member function, a member class
9719 // or a static data member of a class template specialization, the name of
9720 // the class template specialization in the qualified-id for the member
9721 // name shall be a simple-template-id.
9723 // C++98 has the same restriction, just worded differently.
9724 FunctionTemplateDecl *FunTmpl = Specialization->getPrimaryTemplate();
9725 if (D.getName().getKind() != UnqualifiedIdKind::IK_TemplateId && !FunTmpl &&
9726 D.getCXXScopeSpec().isSet() &&
9727 !ScopeSpecifierHasTemplateId(D.getCXXScopeSpec()))
9728 Diag(D.getIdentifierLoc(),
9729 diag::ext_explicit_instantiation_without_qualified_id)
9730 << Specialization << D.getCXXScopeSpec().getRange();
9732 CheckExplicitInstantiation(
9734 FunTmpl ? (NamedDecl *)FunTmpl
9735 : Specialization->getInstantiatedFromMemberFunction(),
9736 D.getIdentifierLoc(), D.getCXXScopeSpec().isSet(), TSK);
9738 // FIXME: Create some kind of ExplicitInstantiationDecl here.
9739 return (Decl*) nullptr;
9743 Sema::ActOnDependentTag(Scope *S, unsigned TagSpec, TagUseKind TUK,
9744 const CXXScopeSpec &SS, IdentifierInfo *Name,
9745 SourceLocation TagLoc, SourceLocation NameLoc) {
9746 // This has to hold, because SS is expected to be defined.
9747 assert(Name && "Expected a name in a dependent tag");
9749 NestedNameSpecifier *NNS = SS.getScopeRep();
9753 TagTypeKind Kind = TypeWithKeyword::getTagTypeKindForTypeSpec(TagSpec);
9755 if (TUK == TUK_Declaration || TUK == TUK_Definition) {
9756 Diag(NameLoc, diag::err_dependent_tag_decl)
9757 << (TUK == TUK_Definition) << Kind << SS.getRange();
9761 // Create the resulting type.
9762 ElaboratedTypeKeyword Kwd = TypeWithKeyword::getKeywordForTagTypeKind(Kind);
9763 QualType Result = Context.getDependentNameType(Kwd, NNS, Name);
9765 // Create type-source location information for this type.
9767 DependentNameTypeLoc TL = TLB.push<DependentNameTypeLoc>(Result);
9768 TL.setElaboratedKeywordLoc(TagLoc);
9769 TL.setQualifierLoc(SS.getWithLocInContext(Context));
9770 TL.setNameLoc(NameLoc);
9771 return CreateParsedType(Result, TLB.getTypeSourceInfo(Context, Result));
9775 Sema::ActOnTypenameType(Scope *S, SourceLocation TypenameLoc,
9776 const CXXScopeSpec &SS, const IdentifierInfo &II,
9777 SourceLocation IdLoc) {
9781 if (TypenameLoc.isValid() && S && !S->getTemplateParamParent())
9783 getLangOpts().CPlusPlus11 ?
9784 diag::warn_cxx98_compat_typename_outside_of_template :
9785 diag::ext_typename_outside_of_template)
9786 << FixItHint::CreateRemoval(TypenameLoc);
9788 NestedNameSpecifierLoc QualifierLoc = SS.getWithLocInContext(Context);
9789 QualType T = CheckTypenameType(TypenameLoc.isValid()? ETK_Typename : ETK_None,
9790 TypenameLoc, QualifierLoc, II, IdLoc);
9794 TypeSourceInfo *TSI = Context.CreateTypeSourceInfo(T);
9795 if (isa<DependentNameType>(T)) {
9796 DependentNameTypeLoc TL = TSI->getTypeLoc().castAs<DependentNameTypeLoc>();
9797 TL.setElaboratedKeywordLoc(TypenameLoc);
9798 TL.setQualifierLoc(QualifierLoc);
9799 TL.setNameLoc(IdLoc);
9801 ElaboratedTypeLoc TL = TSI->getTypeLoc().castAs<ElaboratedTypeLoc>();
9802 TL.setElaboratedKeywordLoc(TypenameLoc);
9803 TL.setQualifierLoc(QualifierLoc);
9804 TL.getNamedTypeLoc().castAs<TypeSpecTypeLoc>().setNameLoc(IdLoc);
9807 return CreateParsedType(T, TSI);
9811 Sema::ActOnTypenameType(Scope *S,
9812 SourceLocation TypenameLoc,
9813 const CXXScopeSpec &SS,
9814 SourceLocation TemplateKWLoc,
9815 TemplateTy TemplateIn,
9816 IdentifierInfo *TemplateII,
9817 SourceLocation TemplateIILoc,
9818 SourceLocation LAngleLoc,
9819 ASTTemplateArgsPtr TemplateArgsIn,
9820 SourceLocation RAngleLoc) {
9821 if (TypenameLoc.isValid() && S && !S->getTemplateParamParent())
9823 getLangOpts().CPlusPlus11 ?
9824 diag::warn_cxx98_compat_typename_outside_of_template :
9825 diag::ext_typename_outside_of_template)
9826 << FixItHint::CreateRemoval(TypenameLoc);
9828 // Strangely, non-type results are not ignored by this lookup, so the
9829 // program is ill-formed if it finds an injected-class-name.
9830 if (TypenameLoc.isValid()) {
9832 dyn_cast_or_null<CXXRecordDecl>(computeDeclContext(SS, false));
9833 if (LookupRD && LookupRD->getIdentifier() == TemplateII) {
9835 diag::ext_out_of_line_qualified_id_type_names_constructor)
9836 << TemplateII << 0 /*injected-class-name used as template name*/
9837 << (TemplateKWLoc.isValid() ? 1 : 0 /*'template'/'typename' keyword*/);
9841 // Translate the parser's template argument list in our AST format.
9842 TemplateArgumentListInfo TemplateArgs(LAngleLoc, RAngleLoc);
9843 translateTemplateArguments(TemplateArgsIn, TemplateArgs);
9845 TemplateName Template = TemplateIn.get();
9846 if (DependentTemplateName *DTN = Template.getAsDependentTemplateName()) {
9847 // Construct a dependent template specialization type.
9848 assert(DTN && "dependent template has non-dependent name?");
9849 assert(DTN->getQualifier() == SS.getScopeRep());
9850 QualType T = Context.getDependentTemplateSpecializationType(ETK_Typename,
9851 DTN->getQualifier(),
9852 DTN->getIdentifier(),
9855 // Create source-location information for this type.
9856 TypeLocBuilder Builder;
9857 DependentTemplateSpecializationTypeLoc SpecTL
9858 = Builder.push<DependentTemplateSpecializationTypeLoc>(T);
9859 SpecTL.setElaboratedKeywordLoc(TypenameLoc);
9860 SpecTL.setQualifierLoc(SS.getWithLocInContext(Context));
9861 SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
9862 SpecTL.setTemplateNameLoc(TemplateIILoc);
9863 SpecTL.setLAngleLoc(LAngleLoc);
9864 SpecTL.setRAngleLoc(RAngleLoc);
9865 for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I)
9866 SpecTL.setArgLocInfo(I, TemplateArgs[I].getLocInfo());
9867 return CreateParsedType(T, Builder.getTypeSourceInfo(Context, T));
9870 QualType T = CheckTemplateIdType(Template, TemplateIILoc, TemplateArgs);
9874 // Provide source-location information for the template specialization type.
9875 TypeLocBuilder Builder;
9876 TemplateSpecializationTypeLoc SpecTL
9877 = Builder.push<TemplateSpecializationTypeLoc>(T);
9878 SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
9879 SpecTL.setTemplateNameLoc(TemplateIILoc);
9880 SpecTL.setLAngleLoc(LAngleLoc);
9881 SpecTL.setRAngleLoc(RAngleLoc);
9882 for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I)
9883 SpecTL.setArgLocInfo(I, TemplateArgs[I].getLocInfo());
9885 T = Context.getElaboratedType(ETK_Typename, SS.getScopeRep(), T);
9886 ElaboratedTypeLoc TL = Builder.push<ElaboratedTypeLoc>(T);
9887 TL.setElaboratedKeywordLoc(TypenameLoc);
9888 TL.setQualifierLoc(SS.getWithLocInContext(Context));
9890 TypeSourceInfo *TSI = Builder.getTypeSourceInfo(Context, T);
9891 return CreateParsedType(T, TSI);
9895 /// Determine whether this failed name lookup should be treated as being
9896 /// disabled by a usage of std::enable_if.
9897 static bool isEnableIf(NestedNameSpecifierLoc NNS, const IdentifierInfo &II,
9898 SourceRange &CondRange, Expr *&Cond) {
9899 // We must be looking for a ::type...
9900 if (!II.isStr("type"))
9903 // ... within an explicitly-written template specialization...
9904 if (!NNS || !NNS.getNestedNameSpecifier()->getAsType())
9906 TypeLoc EnableIfTy = NNS.getTypeLoc();
9907 TemplateSpecializationTypeLoc EnableIfTSTLoc =
9908 EnableIfTy.getAs<TemplateSpecializationTypeLoc>();
9909 if (!EnableIfTSTLoc || EnableIfTSTLoc.getNumArgs() == 0)
9911 const TemplateSpecializationType *EnableIfTST = EnableIfTSTLoc.getTypePtr();
9913 // ... which names a complete class template declaration...
9914 const TemplateDecl *EnableIfDecl =
9915 EnableIfTST->getTemplateName().getAsTemplateDecl();
9916 if (!EnableIfDecl || EnableIfTST->isIncompleteType())
9919 // ... called "enable_if".
9920 const IdentifierInfo *EnableIfII =
9921 EnableIfDecl->getDeclName().getAsIdentifierInfo();
9922 if (!EnableIfII || !EnableIfII->isStr("enable_if"))
9925 // Assume the first template argument is the condition.
9926 CondRange = EnableIfTSTLoc.getArgLoc(0).getSourceRange();
9928 // Dig out the condition.
9930 if (EnableIfTSTLoc.getArgLoc(0).getArgument().getKind()
9931 != TemplateArgument::Expression)
9934 Cond = EnableIfTSTLoc.getArgLoc(0).getSourceExpression();
9936 // Ignore Boolean literals; they add no value.
9937 if (isa<CXXBoolLiteralExpr>(Cond->IgnoreParenCasts()))
9943 /// Build the type that describes a C++ typename specifier,
9944 /// e.g., "typename T::type".
9946 Sema::CheckTypenameType(ElaboratedTypeKeyword Keyword,
9947 SourceLocation KeywordLoc,
9948 NestedNameSpecifierLoc QualifierLoc,
9949 const IdentifierInfo &II,
9950 SourceLocation IILoc) {
9952 SS.Adopt(QualifierLoc);
9954 DeclContext *Ctx = computeDeclContext(SS);
9956 // If the nested-name-specifier is dependent and couldn't be
9957 // resolved to a type, build a typename type.
9958 assert(QualifierLoc.getNestedNameSpecifier()->isDependent());
9959 return Context.getDependentNameType(Keyword,
9960 QualifierLoc.getNestedNameSpecifier(),
9964 // If the nested-name-specifier refers to the current instantiation,
9965 // the "typename" keyword itself is superfluous. In C++03, the
9966 // program is actually ill-formed. However, DR 382 (in C++0x CD1)
9967 // allows such extraneous "typename" keywords, and we retroactively
9968 // apply this DR to C++03 code with only a warning. In any case we continue.
9970 if (RequireCompleteDeclContext(SS, Ctx))
9973 DeclarationName Name(&II);
9974 LookupResult Result(*this, Name, IILoc, LookupOrdinaryName);
9975 LookupQualifiedName(Result, Ctx, SS);
9976 unsigned DiagID = 0;
9977 Decl *Referenced = nullptr;
9978 switch (Result.getResultKind()) {
9979 case LookupResult::NotFound: {
9980 // If we're looking up 'type' within a template named 'enable_if', produce
9981 // a more specific diagnostic.
9982 SourceRange CondRange;
9983 Expr *Cond = nullptr;
9984 if (isEnableIf(QualifierLoc, II, CondRange, Cond)) {
9985 // If we have a condition, narrow it down to the specific failed
9989 std::string FailedDescription;
9990 std::tie(FailedCond, FailedDescription) =
9991 findFailedBooleanCondition(Cond);
9993 Diag(FailedCond->getExprLoc(),
9994 diag::err_typename_nested_not_found_requirement)
9995 << FailedDescription
9996 << FailedCond->getSourceRange();
10000 Diag(CondRange.getBegin(), diag::err_typename_nested_not_found_enable_if)
10001 << Ctx << CondRange;
10005 DiagID = diag::err_typename_nested_not_found;
10009 case LookupResult::FoundUnresolvedValue: {
10010 // We found a using declaration that is a value. Most likely, the using
10011 // declaration itself is meant to have the 'typename' keyword.
10012 SourceRange FullRange(KeywordLoc.isValid() ? KeywordLoc : SS.getBeginLoc(),
10014 Diag(IILoc, diag::err_typename_refers_to_using_value_decl)
10015 << Name << Ctx << FullRange;
10016 if (UnresolvedUsingValueDecl *Using
10017 = dyn_cast<UnresolvedUsingValueDecl>(Result.getRepresentativeDecl())){
10018 SourceLocation Loc = Using->getQualifierLoc().getBeginLoc();
10019 Diag(Loc, diag::note_using_value_decl_missing_typename)
10020 << FixItHint::CreateInsertion(Loc, "typename ");
10023 // Fall through to create a dependent typename type, from which we can recover
10027 case LookupResult::NotFoundInCurrentInstantiation:
10028 // Okay, it's a member of an unknown instantiation.
10029 return Context.getDependentNameType(Keyword,
10030 QualifierLoc.getNestedNameSpecifier(),
10033 case LookupResult::Found:
10034 if (TypeDecl *Type = dyn_cast<TypeDecl>(Result.getFoundDecl())) {
10035 // C++ [class.qual]p2:
10036 // In a lookup in which function names are not ignored and the
10037 // nested-name-specifier nominates a class C, if the name specified
10038 // after the nested-name-specifier, when looked up in C, is the
10039 // injected-class-name of C [...] then the name is instead considered
10040 // to name the constructor of class C.
10042 // Unlike in an elaborated-type-specifier, function names are not ignored
10043 // in typename-specifier lookup. However, they are ignored in all the
10044 // contexts where we form a typename type with no keyword (that is, in
10045 // mem-initializer-ids, base-specifiers, and elaborated-type-specifiers).
10047 // FIXME: That's not strictly true: mem-initializer-id lookup does not
10048 // ignore functions, but that appears to be an oversight.
10049 auto *LookupRD = dyn_cast_or_null<CXXRecordDecl>(Ctx);
10050 auto *FoundRD = dyn_cast<CXXRecordDecl>(Type);
10051 if (Keyword == ETK_Typename && LookupRD && FoundRD &&
10052 FoundRD->isInjectedClassName() &&
10053 declaresSameEntity(LookupRD, cast<Decl>(FoundRD->getParent())))
10054 Diag(IILoc, diag::ext_out_of_line_qualified_id_type_names_constructor)
10055 << &II << 1 << 0 /*'typename' keyword used*/;
10057 // We found a type. Build an ElaboratedType, since the
10058 // typename-specifier was just sugar.
10059 MarkAnyDeclReferenced(Type->getLocation(), Type, /*OdrUse=*/false);
10060 return Context.getElaboratedType(Keyword,
10061 QualifierLoc.getNestedNameSpecifier(),
10062 Context.getTypeDeclType(Type));
10065 // C++ [dcl.type.simple]p2:
10066 // A type-specifier of the form
10067 // typename[opt] nested-name-specifier[opt] template-name
10068 // is a placeholder for a deduced class type [...].
10069 if (getLangOpts().CPlusPlus17) {
10070 if (auto *TD = getAsTypeTemplateDecl(Result.getFoundDecl())) {
10071 return Context.getElaboratedType(
10072 Keyword, QualifierLoc.getNestedNameSpecifier(),
10073 Context.getDeducedTemplateSpecializationType(TemplateName(TD),
10074 QualType(), false));
10078 DiagID = diag::err_typename_nested_not_type;
10079 Referenced = Result.getFoundDecl();
10082 case LookupResult::FoundOverloaded:
10083 DiagID = diag::err_typename_nested_not_type;
10084 Referenced = *Result.begin();
10087 case LookupResult::Ambiguous:
10091 // If we get here, it's because name lookup did not find a
10092 // type. Emit an appropriate diagnostic and return an error.
10093 SourceRange FullRange(KeywordLoc.isValid() ? KeywordLoc : SS.getBeginLoc(),
10095 Diag(IILoc, DiagID) << FullRange << Name << Ctx;
10097 Diag(Referenced->getLocation(), diag::note_typename_refers_here)
10103 // See Sema::RebuildTypeInCurrentInstantiation
10104 class CurrentInstantiationRebuilder
10105 : public TreeTransform<CurrentInstantiationRebuilder> {
10106 SourceLocation Loc;
10107 DeclarationName Entity;
10110 typedef TreeTransform<CurrentInstantiationRebuilder> inherited;
10112 CurrentInstantiationRebuilder(Sema &SemaRef,
10113 SourceLocation Loc,
10114 DeclarationName Entity)
10115 : TreeTransform<CurrentInstantiationRebuilder>(SemaRef),
10116 Loc(Loc), Entity(Entity) { }
10118 /// Determine whether the given type \p T has already been
10121 /// For the purposes of type reconstruction, a type has already been
10122 /// transformed if it is NULL or if it is not dependent.
10123 bool AlreadyTransformed(QualType T) {
10124 return T.isNull() || !T->isDependentType();
10127 /// Returns the location of the entity whose type is being
10129 SourceLocation getBaseLocation() { return Loc; }
10131 /// Returns the name of the entity whose type is being rebuilt.
10132 DeclarationName getBaseEntity() { return Entity; }
10134 /// Sets the "base" location and entity when that
10135 /// information is known based on another transformation.
10136 void setBase(SourceLocation Loc, DeclarationName Entity) {
10138 this->Entity = Entity;
10141 ExprResult TransformLambdaExpr(LambdaExpr *E) {
10142 // Lambdas never need to be transformed.
10146 } // end anonymous namespace
10148 /// Rebuilds a type within the context of the current instantiation.
10150 /// The type \p T is part of the type of an out-of-line member definition of
10151 /// a class template (or class template partial specialization) that was parsed
10152 /// and constructed before we entered the scope of the class template (or
10153 /// partial specialization thereof). This routine will rebuild that type now
10154 /// that we have entered the declarator's scope, which may produce different
10155 /// canonical types, e.g.,
10158 /// template<typename T>
10160 /// typedef T* pointer;
10161 /// pointer data();
10164 /// template<typename T>
10165 /// typename X<T>::pointer X<T>::data() { ... }
10168 /// Here, the type "typename X<T>::pointer" will be created as a DependentNameType,
10169 /// since we do not know that we can look into X<T> when we parsed the type.
10170 /// This function will rebuild the type, performing the lookup of "pointer"
10171 /// in X<T> and returning an ElaboratedType whose canonical type is the same
10172 /// as the canonical type of T*, allowing the return types of the out-of-line
10173 /// definition and the declaration to match.
10174 TypeSourceInfo *Sema::RebuildTypeInCurrentInstantiation(TypeSourceInfo *T,
10175 SourceLocation Loc,
10176 DeclarationName Name) {
10177 if (!T || !T->getType()->isDependentType())
10180 CurrentInstantiationRebuilder Rebuilder(*this, Loc, Name);
10181 return Rebuilder.TransformType(T);
10184 ExprResult Sema::RebuildExprInCurrentInstantiation(Expr *E) {
10185 CurrentInstantiationRebuilder Rebuilder(*this, E->getExprLoc(),
10186 DeclarationName());
10187 return Rebuilder.TransformExpr(E);
10190 bool Sema::RebuildNestedNameSpecifierInCurrentInstantiation(CXXScopeSpec &SS) {
10191 if (SS.isInvalid())
10194 NestedNameSpecifierLoc QualifierLoc = SS.getWithLocInContext(Context);
10195 CurrentInstantiationRebuilder Rebuilder(*this, SS.getRange().getBegin(),
10196 DeclarationName());
10197 NestedNameSpecifierLoc Rebuilt
10198 = Rebuilder.TransformNestedNameSpecifierLoc(QualifierLoc);
10206 /// Rebuild the template parameters now that we know we're in a current
10208 bool Sema::RebuildTemplateParamsInCurrentInstantiation(
10209 TemplateParameterList *Params) {
10210 for (unsigned I = 0, N = Params->size(); I != N; ++I) {
10211 Decl *Param = Params->getParam(I);
10213 // There is nothing to rebuild in a type parameter.
10214 if (isa<TemplateTypeParmDecl>(Param))
10217 // Rebuild the template parameter list of a template template parameter.
10218 if (TemplateTemplateParmDecl *TTP
10219 = dyn_cast<TemplateTemplateParmDecl>(Param)) {
10220 if (RebuildTemplateParamsInCurrentInstantiation(
10221 TTP->getTemplateParameters()))
10227 // Rebuild the type of a non-type template parameter.
10228 NonTypeTemplateParmDecl *NTTP = cast<NonTypeTemplateParmDecl>(Param);
10229 TypeSourceInfo *NewTSI
10230 = RebuildTypeInCurrentInstantiation(NTTP->getTypeSourceInfo(),
10231 NTTP->getLocation(),
10232 NTTP->getDeclName());
10236 if (NewTSI->getType()->isUndeducedType()) {
10237 // C++17 [temp.dep.expr]p3:
10238 // An id-expression is type-dependent if it contains
10239 // - an identifier associated by name lookup with a non-type
10240 // template-parameter declared with a type that contains a
10241 // placeholder type (7.1.7.4),
10242 NewTSI = SubstAutoTypeSourceInfo(NewTSI, Context.DependentTy);
10245 if (NewTSI != NTTP->getTypeSourceInfo()) {
10246 NTTP->setTypeSourceInfo(NewTSI);
10247 NTTP->setType(NewTSI->getType());
10254 /// Produces a formatted string that describes the binding of
10255 /// template parameters to template arguments.
10257 Sema::getTemplateArgumentBindingsText(const TemplateParameterList *Params,
10258 const TemplateArgumentList &Args) {
10259 return getTemplateArgumentBindingsText(Params, Args.data(), Args.size());
10263 Sema::getTemplateArgumentBindingsText(const TemplateParameterList *Params,
10264 const TemplateArgument *Args,
10265 unsigned NumArgs) {
10266 SmallString<128> Str;
10267 llvm::raw_svector_ostream Out(Str);
10269 if (!Params || Params->size() == 0 || NumArgs == 0)
10270 return std::string();
10272 for (unsigned I = 0, N = Params->size(); I != N; ++I) {
10281 if (const IdentifierInfo *Id = Params->getParam(I)->getIdentifier()) {
10282 Out << Id->getName();
10288 Args[I].print(getPrintingPolicy(), Out);
10295 void Sema::MarkAsLateParsedTemplate(FunctionDecl *FD, Decl *FnD,
10296 CachedTokens &Toks) {
10300 auto LPT = llvm::make_unique<LateParsedTemplate>();
10302 // Take tokens to avoid allocations
10303 LPT->Toks.swap(Toks);
10305 LateParsedTemplateMap.insert(std::make_pair(FD, std::move(LPT)));
10307 FD->setLateTemplateParsed(true);
10310 void Sema::UnmarkAsLateParsedTemplate(FunctionDecl *FD) {
10313 FD->setLateTemplateParsed(false);
10316 bool Sema::IsInsideALocalClassWithinATemplateFunction() {
10317 DeclContext *DC = CurContext;
10320 if (CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(CurContext)) {
10321 const FunctionDecl *FD = RD->isLocalClass();
10322 return (FD && FD->getTemplatedKind() != FunctionDecl::TK_NonTemplate);
10323 } else if (DC->isTranslationUnit() || DC->isNamespace())
10326 DC = DC->getParent();
10332 /// Walk the path from which a declaration was instantiated, and check
10333 /// that every explicit specialization along that path is visible. This enforces
10334 /// C++ [temp.expl.spec]/6:
10336 /// If a template, a member template or a member of a class template is
10337 /// explicitly specialized then that specialization shall be declared before
10338 /// the first use of that specialization that would cause an implicit
10339 /// instantiation to take place, in every translation unit in which such a
10340 /// use occurs; no diagnostic is required.
10342 /// and also C++ [temp.class.spec]/1:
10344 /// A partial specialization shall be declared before the first use of a
10345 /// class template specialization that would make use of the partial
10346 /// specialization as the result of an implicit or explicit instantiation
10347 /// in every translation unit in which such a use occurs; no diagnostic is
10349 class ExplicitSpecializationVisibilityChecker {
10351 SourceLocation Loc;
10352 llvm::SmallVector<Module *, 8> Modules;
10355 ExplicitSpecializationVisibilityChecker(Sema &S, SourceLocation Loc)
10356 : S(S), Loc(Loc) {}
10358 void check(NamedDecl *ND) {
10359 if (auto *FD = dyn_cast<FunctionDecl>(ND))
10360 return checkImpl(FD);
10361 if (auto *RD = dyn_cast<CXXRecordDecl>(ND))
10362 return checkImpl(RD);
10363 if (auto *VD = dyn_cast<VarDecl>(ND))
10364 return checkImpl(VD);
10365 if (auto *ED = dyn_cast<EnumDecl>(ND))
10366 return checkImpl(ED);
10370 void diagnose(NamedDecl *D, bool IsPartialSpec) {
10371 auto Kind = IsPartialSpec ? Sema::MissingImportKind::PartialSpecialization
10372 : Sema::MissingImportKind::ExplicitSpecialization;
10373 const bool Recover = true;
10375 // If we got a custom set of modules (because only a subset of the
10376 // declarations are interesting), use them, otherwise let
10377 // diagnoseMissingImport intelligently pick some.
10378 if (Modules.empty())
10379 S.diagnoseMissingImport(Loc, D, Kind, Recover);
10381 S.diagnoseMissingImport(Loc, D, D->getLocation(), Modules, Kind, Recover);
10384 // Check a specific declaration. There are three problematic cases:
10386 // 1) The declaration is an explicit specialization of a template
10388 // 2) The declaration is an explicit specialization of a member of an
10389 // templated class.
10390 // 3) The declaration is an instantiation of a template, and that template
10391 // is an explicit specialization of a member of a templated class.
10393 // We don't need to go any deeper than that, as the instantiation of the
10394 // surrounding class / etc is not triggered by whatever triggered this
10395 // instantiation, and thus should be checked elsewhere.
10396 template<typename SpecDecl>
10397 void checkImpl(SpecDecl *Spec) {
10398 bool IsHiddenExplicitSpecialization = false;
10399 if (Spec->getTemplateSpecializationKind() == TSK_ExplicitSpecialization) {
10400 IsHiddenExplicitSpecialization =
10401 Spec->getMemberSpecializationInfo()
10402 ? !S.hasVisibleMemberSpecialization(Spec, &Modules)
10403 : !S.hasVisibleExplicitSpecialization(Spec, &Modules);
10405 checkInstantiated(Spec);
10408 if (IsHiddenExplicitSpecialization)
10409 diagnose(Spec->getMostRecentDecl(), false);
10412 void checkInstantiated(FunctionDecl *FD) {
10413 if (auto *TD = FD->getPrimaryTemplate())
10417 void checkInstantiated(CXXRecordDecl *RD) {
10418 auto *SD = dyn_cast<ClassTemplateSpecializationDecl>(RD);
10422 auto From = SD->getSpecializedTemplateOrPartial();
10423 if (auto *TD = From.dyn_cast<ClassTemplateDecl *>())
10425 else if (auto *TD =
10426 From.dyn_cast<ClassTemplatePartialSpecializationDecl *>()) {
10427 if (!S.hasVisibleDeclaration(TD))
10428 diagnose(TD, true);
10433 void checkInstantiated(VarDecl *RD) {
10434 auto *SD = dyn_cast<VarTemplateSpecializationDecl>(RD);
10438 auto From = SD->getSpecializedTemplateOrPartial();
10439 if (auto *TD = From.dyn_cast<VarTemplateDecl *>())
10441 else if (auto *TD =
10442 From.dyn_cast<VarTemplatePartialSpecializationDecl *>()) {
10443 if (!S.hasVisibleDeclaration(TD))
10444 diagnose(TD, true);
10449 void checkInstantiated(EnumDecl *FD) {}
10451 template<typename TemplDecl>
10452 void checkTemplate(TemplDecl *TD) {
10453 if (TD->isMemberSpecialization()) {
10454 if (!S.hasVisibleMemberSpecialization(TD, &Modules))
10455 diagnose(TD->getMostRecentDecl(), false);
10459 } // end anonymous namespace
10461 void Sema::checkSpecializationVisibility(SourceLocation Loc, NamedDecl *Spec) {
10462 if (!getLangOpts().Modules)
10465 ExplicitSpecializationVisibilityChecker(*this, Loc).check(Spec);
10468 /// Check whether a template partial specialization that we've discovered
10469 /// is hidden, and produce suitable diagnostics if so.
10470 void Sema::checkPartialSpecializationVisibility(SourceLocation Loc,
10472 llvm::SmallVector<Module *, 8> Modules;
10473 if (!hasVisibleDeclaration(Spec, &Modules))
10474 diagnoseMissingImport(Loc, Spec, Spec->getLocation(), Modules,
10475 MissingImportKind::PartialSpecialization,