1 //===------- SemaTemplate.cpp - Semantic Analysis for C++ Templates -------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //===----------------------------------------------------------------------===//
9 // This file implements semantic analysis for C++ templates.
10 //===----------------------------------------------------------------------===//
12 #include "TreeTransform.h"
13 #include "clang/AST/ASTConsumer.h"
14 #include "clang/AST/ASTContext.h"
15 #include "clang/AST/DeclFriend.h"
16 #include "clang/AST/DeclTemplate.h"
17 #include "clang/AST/Expr.h"
18 #include "clang/AST/ExprCXX.h"
19 #include "clang/AST/RecursiveASTVisitor.h"
20 #include "clang/AST/TypeVisitor.h"
21 #include "clang/Basic/Builtins.h"
22 #include "clang/Basic/LangOptions.h"
23 #include "clang/Basic/PartialDiagnostic.h"
24 #include "clang/Basic/TargetInfo.h"
25 #include "clang/Sema/DeclSpec.h"
26 #include "clang/Sema/Lookup.h"
27 #include "clang/Sema/ParsedTemplate.h"
28 #include "clang/Sema/Scope.h"
29 #include "clang/Sema/SemaInternal.h"
30 #include "clang/Sema/Template.h"
31 #include "clang/Sema/TemplateDeduction.h"
32 #include "llvm/ADT/SmallBitVector.h"
33 #include "llvm/ADT/SmallString.h"
34 #include "llvm/ADT/StringExtras.h"
37 using namespace clang;
40 // Exported for use by Parser.
42 clang::getTemplateParamsRange(TemplateParameterList const * const *Ps,
44 if (!N) return SourceRange();
45 return SourceRange(Ps[0]->getTemplateLoc(), Ps[N-1]->getRAngleLoc());
49 /// \brief [temp.constr.decl]p2: A template's associated constraints are
50 /// defined as a single constraint-expression derived from the introduced
51 /// constraint-expressions [ ... ].
53 /// \param Params The template parameter list and optional requires-clause.
55 /// \param FD The underlying templated function declaration for a function
57 static Expr *formAssociatedConstraints(TemplateParameterList *Params,
61 static Expr *clang::formAssociatedConstraints(TemplateParameterList *Params,
63 // FIXME: Concepts: collect additional introduced constraint-expressions
64 assert(!FD && "Cannot collect constraints from function declaration yet.");
65 return Params->getRequiresClause();
68 /// \brief Determine whether the declaration found is acceptable as the name
69 /// of a template and, if so, return that template declaration. Otherwise,
71 static NamedDecl *isAcceptableTemplateName(ASTContext &Context,
73 bool AllowFunctionTemplates) {
74 NamedDecl *D = Orig->getUnderlyingDecl();
76 if (isa<TemplateDecl>(D)) {
77 if (!AllowFunctionTemplates && isa<FunctionTemplateDecl>(D))
83 if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(D)) {
84 // C++ [temp.local]p1:
85 // Like normal (non-template) classes, class templates have an
86 // injected-class-name (Clause 9). The injected-class-name
87 // can be used with or without a template-argument-list. When
88 // it is used without a template-argument-list, it is
89 // equivalent to the injected-class-name followed by the
90 // template-parameters of the class template enclosed in
91 // <>. When it is used with a template-argument-list, it
92 // refers to the specified class template specialization,
93 // which could be the current specialization or another
95 if (Record->isInjectedClassName()) {
96 Record = cast<CXXRecordDecl>(Record->getDeclContext());
97 if (Record->getDescribedClassTemplate())
98 return Record->getDescribedClassTemplate();
100 if (ClassTemplateSpecializationDecl *Spec
101 = dyn_cast<ClassTemplateSpecializationDecl>(Record))
102 return Spec->getSpecializedTemplate();
111 void Sema::FilterAcceptableTemplateNames(LookupResult &R,
112 bool AllowFunctionTemplates) {
113 // The set of class templates we've already seen.
114 llvm::SmallPtrSet<ClassTemplateDecl *, 8> ClassTemplates;
115 LookupResult::Filter filter = R.makeFilter();
116 while (filter.hasNext()) {
117 NamedDecl *Orig = filter.next();
118 NamedDecl *Repl = isAcceptableTemplateName(Context, Orig,
119 AllowFunctionTemplates);
122 else if (Repl != Orig) {
124 // C++ [temp.local]p3:
125 // A lookup that finds an injected-class-name (10.2) can result in an
126 // ambiguity in certain cases (for example, if it is found in more than
127 // one base class). If all of the injected-class-names that are found
128 // refer to specializations of the same class template, and if the name
129 // is used as a template-name, the reference refers to the class
130 // template itself and not a specialization thereof, and is not
132 if (ClassTemplateDecl *ClassTmpl = dyn_cast<ClassTemplateDecl>(Repl))
133 if (!ClassTemplates.insert(ClassTmpl).second) {
138 // FIXME: we promote access to public here as a workaround to
139 // the fact that LookupResult doesn't let us remember that we
140 // found this template through a particular injected class name,
141 // which means we end up doing nasty things to the invariants.
142 // Pretending that access is public is *much* safer.
143 filter.replace(Repl, AS_public);
149 bool Sema::hasAnyAcceptableTemplateNames(LookupResult &R,
150 bool AllowFunctionTemplates) {
151 for (LookupResult::iterator I = R.begin(), IEnd = R.end(); I != IEnd; ++I)
152 if (isAcceptableTemplateName(Context, *I, AllowFunctionTemplates))
158 TemplateNameKind Sema::isTemplateName(Scope *S,
160 bool hasTemplateKeyword,
162 ParsedType ObjectTypePtr,
163 bool EnteringContext,
164 TemplateTy &TemplateResult,
165 bool &MemberOfUnknownSpecialization) {
166 assert(getLangOpts().CPlusPlus && "No template names in C!");
168 DeclarationName TName;
169 MemberOfUnknownSpecialization = false;
171 switch (Name.getKind()) {
172 case UnqualifiedId::IK_Identifier:
173 TName = DeclarationName(Name.Identifier);
176 case UnqualifiedId::IK_OperatorFunctionId:
177 TName = Context.DeclarationNames.getCXXOperatorName(
178 Name.OperatorFunctionId.Operator);
181 case UnqualifiedId::IK_LiteralOperatorId:
182 TName = Context.DeclarationNames.getCXXLiteralOperatorName(Name.Identifier);
186 return TNK_Non_template;
189 QualType ObjectType = ObjectTypePtr.get();
191 LookupResult R(*this, TName, Name.getLocStart(), LookupOrdinaryName);
192 LookupTemplateName(R, S, SS, ObjectType, EnteringContext,
193 MemberOfUnknownSpecialization);
194 if (R.empty()) return TNK_Non_template;
195 if (R.isAmbiguous()) {
196 // Suppress diagnostics; we'll redo this lookup later.
197 R.suppressDiagnostics();
199 // FIXME: we might have ambiguous templates, in which case we
200 // should at least parse them properly!
201 return TNK_Non_template;
204 TemplateName Template;
205 TemplateNameKind TemplateKind;
207 unsigned ResultCount = R.end() - R.begin();
208 if (ResultCount > 1) {
209 // We assume that we'll preserve the qualifier from a function
210 // template name in other ways.
211 Template = Context.getOverloadedTemplateName(R.begin(), R.end());
212 TemplateKind = TNK_Function_template;
214 // We'll do this lookup again later.
215 R.suppressDiagnostics();
217 TemplateDecl *TD = cast<TemplateDecl>((*R.begin())->getUnderlyingDecl());
219 if (SS.isSet() && !SS.isInvalid()) {
220 NestedNameSpecifier *Qualifier = SS.getScopeRep();
221 Template = Context.getQualifiedTemplateName(Qualifier,
222 hasTemplateKeyword, TD);
224 Template = TemplateName(TD);
227 if (isa<FunctionTemplateDecl>(TD)) {
228 TemplateKind = TNK_Function_template;
230 // We'll do this lookup again later.
231 R.suppressDiagnostics();
233 assert(isa<ClassTemplateDecl>(TD) || isa<TemplateTemplateParmDecl>(TD) ||
234 isa<TypeAliasTemplateDecl>(TD) || isa<VarTemplateDecl>(TD) ||
235 isa<BuiltinTemplateDecl>(TD));
237 isa<VarTemplateDecl>(TD) ? TNK_Var_template : TNK_Type_template;
241 TemplateResult = TemplateTy::make(Template);
245 bool Sema::isDeductionGuideName(Scope *S, const IdentifierInfo &Name,
246 SourceLocation NameLoc,
247 ParsedTemplateTy *Template) {
249 bool MemberOfUnknownSpecialization = false;
251 // We could use redeclaration lookup here, but we don't need to: the
252 // syntactic form of a deduction guide is enough to identify it even
253 // if we can't look up the template name at all.
254 LookupResult R(*this, DeclarationName(&Name), NameLoc, LookupOrdinaryName);
255 LookupTemplateName(R, S, SS, /*ObjectType*/QualType(),
256 /*EnteringContext*/false, MemberOfUnknownSpecialization);
258 if (R.empty()) return false;
259 if (R.isAmbiguous()) {
260 // FIXME: Diagnose an ambiguity if we find at least one template.
261 R.suppressDiagnostics();
265 // We only treat template-names that name type templates as valid deduction
267 TemplateDecl *TD = R.getAsSingle<TemplateDecl>();
268 if (!TD || !getAsTypeTemplateDecl(TD))
272 *Template = TemplateTy::make(TemplateName(TD));
276 bool Sema::DiagnoseUnknownTemplateName(const IdentifierInfo &II,
277 SourceLocation IILoc,
279 const CXXScopeSpec *SS,
280 TemplateTy &SuggestedTemplate,
281 TemplateNameKind &SuggestedKind) {
282 // We can't recover unless there's a dependent scope specifier preceding the
284 // FIXME: Typo correction?
285 if (!SS || !SS->isSet() || !isDependentScopeSpecifier(*SS) ||
286 computeDeclContext(*SS))
289 // The code is missing a 'template' keyword prior to the dependent template
291 NestedNameSpecifier *Qualifier = (NestedNameSpecifier*)SS->getScopeRep();
292 Diag(IILoc, diag::err_template_kw_missing)
293 << Qualifier << II.getName()
294 << FixItHint::CreateInsertion(IILoc, "template ");
296 = TemplateTy::make(Context.getDependentTemplateName(Qualifier, &II));
297 SuggestedKind = TNK_Dependent_template_name;
301 void Sema::LookupTemplateName(LookupResult &Found,
302 Scope *S, CXXScopeSpec &SS,
304 bool EnteringContext,
305 bool &MemberOfUnknownSpecialization) {
306 // Determine where to perform name lookup
307 MemberOfUnknownSpecialization = false;
308 DeclContext *LookupCtx = nullptr;
309 bool isDependent = false;
310 if (!ObjectType.isNull()) {
311 // This nested-name-specifier occurs in a member access expression, e.g.,
312 // x->B::f, and we are looking into the type of the object.
313 assert(!SS.isSet() && "ObjectType and scope specifier cannot coexist");
314 LookupCtx = computeDeclContext(ObjectType);
315 isDependent = ObjectType->isDependentType();
316 assert((isDependent || !ObjectType->isIncompleteType() ||
317 ObjectType->castAs<TagType>()->isBeingDefined()) &&
318 "Caller should have completed object type");
320 // Template names cannot appear inside an Objective-C class or object type.
321 if (ObjectType->isObjCObjectOrInterfaceType()) {
325 } else if (SS.isSet()) {
326 // This nested-name-specifier occurs after another nested-name-specifier,
327 // so long into the context associated with the prior nested-name-specifier.
328 LookupCtx = computeDeclContext(SS, EnteringContext);
329 isDependent = isDependentScopeSpecifier(SS);
331 // The declaration context must be complete.
332 if (LookupCtx && RequireCompleteDeclContext(SS, LookupCtx))
336 bool ObjectTypeSearchedInScope = false;
337 bool AllowFunctionTemplatesInLookup = true;
339 // Perform "qualified" name lookup into the declaration context we
340 // computed, which is either the type of the base of a member access
341 // expression or the declaration context associated with a prior
342 // nested-name-specifier.
343 LookupQualifiedName(Found, LookupCtx);
344 if (!ObjectType.isNull() && Found.empty()) {
345 // C++ [basic.lookup.classref]p1:
346 // In a class member access expression (5.2.5), if the . or -> token is
347 // immediately followed by an identifier followed by a <, the
348 // identifier must be looked up to determine whether the < is the
349 // beginning of a template argument list (14.2) or a less-than operator.
350 // The identifier is first looked up in the class of the object
351 // expression. If the identifier is not found, it is then looked up in
352 // the context of the entire postfix-expression and shall name a class
353 // or function template.
354 if (S) LookupName(Found, S);
355 ObjectTypeSearchedInScope = true;
356 AllowFunctionTemplatesInLookup = false;
358 } else if (isDependent && (!S || ObjectType.isNull())) {
359 // We cannot look into a dependent object type or nested nme
361 MemberOfUnknownSpecialization = true;
364 // Perform unqualified name lookup in the current scope.
365 LookupName(Found, S);
367 if (!ObjectType.isNull())
368 AllowFunctionTemplatesInLookup = false;
371 if (Found.empty() && !isDependent) {
372 // If we did not find any names, attempt to correct any typos.
373 DeclarationName Name = Found.getLookupName();
375 // Simple filter callback that, for keywords, only accepts the C++ *_cast
376 auto FilterCCC = llvm::make_unique<CorrectionCandidateCallback>();
377 FilterCCC->WantTypeSpecifiers = false;
378 FilterCCC->WantExpressionKeywords = false;
379 FilterCCC->WantRemainingKeywords = false;
380 FilterCCC->WantCXXNamedCasts = true;
381 if (TypoCorrection Corrected = CorrectTypo(
382 Found.getLookupNameInfo(), Found.getLookupKind(), S, &SS,
383 std::move(FilterCCC), CTK_ErrorRecovery, LookupCtx)) {
384 Found.setLookupName(Corrected.getCorrection());
385 if (auto *ND = Corrected.getFoundDecl())
387 FilterAcceptableTemplateNames(Found);
388 if (!Found.empty()) {
390 std::string CorrectedStr(Corrected.getAsString(getLangOpts()));
391 bool DroppedSpecifier = Corrected.WillReplaceSpecifier() &&
392 Name.getAsString() == CorrectedStr;
393 diagnoseTypo(Corrected, PDiag(diag::err_no_member_template_suggest)
394 << Name << LookupCtx << DroppedSpecifier
397 diagnoseTypo(Corrected, PDiag(diag::err_no_template_suggest) << Name);
401 Found.setLookupName(Name);
405 FilterAcceptableTemplateNames(Found, AllowFunctionTemplatesInLookup);
408 MemberOfUnknownSpecialization = true;
412 if (S && !ObjectType.isNull() && !ObjectTypeSearchedInScope &&
413 !getLangOpts().CPlusPlus11) {
414 // C++03 [basic.lookup.classref]p1:
415 // [...] If the lookup in the class of the object expression finds a
416 // template, the name is also looked up in the context of the entire
417 // postfix-expression and [...]
419 // Note: C++11 does not perform this second lookup.
420 LookupResult FoundOuter(*this, Found.getLookupName(), Found.getNameLoc(),
422 LookupName(FoundOuter, S);
423 FilterAcceptableTemplateNames(FoundOuter, /*AllowFunctionTemplates=*/false);
425 if (FoundOuter.empty()) {
426 // - if the name is not found, the name found in the class of the
427 // object expression is used, otherwise
428 } else if (!FoundOuter.getAsSingle<ClassTemplateDecl>() ||
429 FoundOuter.isAmbiguous()) {
430 // - if the name is found in the context of the entire
431 // postfix-expression and does not name a class template, the name
432 // found in the class of the object expression is used, otherwise
434 } else if (!Found.isSuppressingDiagnostics()) {
435 // - if the name found is a class template, it must refer to the same
436 // entity as the one found in the class of the object expression,
437 // otherwise the program is ill-formed.
438 if (!Found.isSingleResult() ||
439 Found.getFoundDecl()->getCanonicalDecl()
440 != FoundOuter.getFoundDecl()->getCanonicalDecl()) {
441 Diag(Found.getNameLoc(),
442 diag::ext_nested_name_member_ref_lookup_ambiguous)
443 << Found.getLookupName()
445 Diag(Found.getRepresentativeDecl()->getLocation(),
446 diag::note_ambig_member_ref_object_type)
448 Diag(FoundOuter.getFoundDecl()->getLocation(),
449 diag::note_ambig_member_ref_scope);
451 // Recover by taking the template that we found in the object
452 // expression's type.
458 void Sema::diagnoseExprIntendedAsTemplateName(Scope *S, ExprResult TemplateName,
460 SourceLocation Greater) {
461 if (TemplateName.isInvalid())
464 DeclarationNameInfo NameInfo;
466 LookupNameKind LookupKind;
468 DeclContext *LookupCtx = nullptr;
469 NamedDecl *Found = nullptr;
471 // Figure out what name we looked up.
472 if (auto *ME = dyn_cast<MemberExpr>(TemplateName.get())) {
473 NameInfo = ME->getMemberNameInfo();
474 SS.Adopt(ME->getQualifierLoc());
475 LookupKind = LookupMemberName;
476 LookupCtx = ME->getBase()->getType()->getAsCXXRecordDecl();
477 Found = ME->getMemberDecl();
479 auto *DRE = cast<DeclRefExpr>(TemplateName.get());
480 NameInfo = DRE->getNameInfo();
481 SS.Adopt(DRE->getQualifierLoc());
482 LookupKind = LookupOrdinaryName;
483 Found = DRE->getFoundDecl();
486 // Try to correct the name by looking for templates and C++ named casts.
487 struct TemplateCandidateFilter : CorrectionCandidateCallback {
488 TemplateCandidateFilter() {
489 WantTypeSpecifiers = false;
490 WantExpressionKeywords = false;
491 WantRemainingKeywords = false;
492 WantCXXNamedCasts = true;
494 bool ValidateCandidate(const TypoCorrection &Candidate) override {
495 if (auto *ND = Candidate.getCorrectionDecl())
496 return isAcceptableTemplateName(ND->getASTContext(), ND, true);
497 return Candidate.isKeyword();
501 DeclarationName Name = NameInfo.getName();
502 if (TypoCorrection Corrected =
503 CorrectTypo(NameInfo, LookupKind, S, &SS,
504 llvm::make_unique<TemplateCandidateFilter>(),
505 CTK_ErrorRecovery, LookupCtx)) {
506 auto *ND = Corrected.getFoundDecl();
508 ND = isAcceptableTemplateName(Context, ND,
509 /*AllowFunctionTemplates*/ true);
510 if (ND || Corrected.isKeyword()) {
512 std::string CorrectedStr(Corrected.getAsString(getLangOpts()));
513 bool DroppedSpecifier = Corrected.WillReplaceSpecifier() &&
514 Name.getAsString() == CorrectedStr;
515 diagnoseTypo(Corrected,
516 PDiag(diag::err_non_template_in_member_template_id_suggest)
517 << Name << LookupCtx << DroppedSpecifier
518 << SS.getRange(), false);
520 diagnoseTypo(Corrected,
521 PDiag(diag::err_non_template_in_template_id_suggest)
525 Diag(Found->getLocation(),
526 diag::note_non_template_in_template_id_found);
531 Diag(NameInfo.getLoc(), diag::err_non_template_in_template_id)
532 << Name << SourceRange(Less, Greater);
534 Diag(Found->getLocation(), diag::note_non_template_in_template_id_found);
537 /// ActOnDependentIdExpression - Handle a dependent id-expression that
538 /// was just parsed. This is only possible with an explicit scope
539 /// specifier naming a dependent type.
541 Sema::ActOnDependentIdExpression(const CXXScopeSpec &SS,
542 SourceLocation TemplateKWLoc,
543 const DeclarationNameInfo &NameInfo,
544 bool isAddressOfOperand,
545 const TemplateArgumentListInfo *TemplateArgs) {
546 DeclContext *DC = getFunctionLevelDeclContext();
548 // C++11 [expr.prim.general]p12:
549 // An id-expression that denotes a non-static data member or non-static
550 // member function of a class can only be used:
552 // - if that id-expression denotes a non-static data member and it
553 // appears in an unevaluated operand.
555 // If this might be the case, form a DependentScopeDeclRefExpr instead of a
556 // CXXDependentScopeMemberExpr. The former can instantiate to either
557 // DeclRefExpr or MemberExpr depending on lookup results, while the latter is
558 // always a MemberExpr.
559 bool MightBeCxx11UnevalField =
560 getLangOpts().CPlusPlus11 && isUnevaluatedContext();
562 // Check if the nested name specifier is an enum type.
564 if (NestedNameSpecifier *NNS = SS.getScopeRep())
565 IsEnum = dyn_cast_or_null<EnumType>(NNS->getAsType());
567 if (!MightBeCxx11UnevalField && !isAddressOfOperand && !IsEnum &&
568 isa<CXXMethodDecl>(DC) && cast<CXXMethodDecl>(DC)->isInstance()) {
569 QualType ThisType = cast<CXXMethodDecl>(DC)->getThisType(Context);
571 // Since the 'this' expression is synthesized, we don't need to
572 // perform the double-lookup check.
573 NamedDecl *FirstQualifierInScope = nullptr;
575 return CXXDependentScopeMemberExpr::Create(
576 Context, /*This*/ nullptr, ThisType, /*IsArrow*/ true,
577 /*Op*/ SourceLocation(), SS.getWithLocInContext(Context), TemplateKWLoc,
578 FirstQualifierInScope, NameInfo, TemplateArgs);
581 return BuildDependentDeclRefExpr(SS, TemplateKWLoc, NameInfo, TemplateArgs);
585 Sema::BuildDependentDeclRefExpr(const CXXScopeSpec &SS,
586 SourceLocation TemplateKWLoc,
587 const DeclarationNameInfo &NameInfo,
588 const TemplateArgumentListInfo *TemplateArgs) {
589 return DependentScopeDeclRefExpr::Create(
590 Context, SS.getWithLocInContext(Context), TemplateKWLoc, NameInfo,
595 /// Determine whether we would be unable to instantiate this template (because
596 /// it either has no definition, or is in the process of being instantiated).
597 bool Sema::DiagnoseUninstantiableTemplate(SourceLocation PointOfInstantiation,
598 NamedDecl *Instantiation,
599 bool InstantiatedFromMember,
600 const NamedDecl *Pattern,
601 const NamedDecl *PatternDef,
602 TemplateSpecializationKind TSK,
603 bool Complain /*= true*/) {
604 assert(isa<TagDecl>(Instantiation) || isa<FunctionDecl>(Instantiation) ||
605 isa<VarDecl>(Instantiation));
607 bool IsEntityBeingDefined = false;
608 if (const TagDecl *TD = dyn_cast_or_null<TagDecl>(PatternDef))
609 IsEntityBeingDefined = TD->isBeingDefined();
611 if (PatternDef && !IsEntityBeingDefined) {
612 NamedDecl *SuggestedDef = nullptr;
613 if (!hasVisibleDefinition(const_cast<NamedDecl*>(PatternDef), &SuggestedDef,
614 /*OnlyNeedComplete*/false)) {
615 // If we're allowed to diagnose this and recover, do so.
616 bool Recover = Complain && !isSFINAEContext();
618 diagnoseMissingImport(PointOfInstantiation, SuggestedDef,
619 Sema::MissingImportKind::Definition, Recover);
625 if (!Complain || (PatternDef && PatternDef->isInvalidDecl()))
628 llvm::Optional<unsigned> Note;
629 QualType InstantiationTy;
630 if (TagDecl *TD = dyn_cast<TagDecl>(Instantiation))
631 InstantiationTy = Context.getTypeDeclType(TD);
633 Diag(PointOfInstantiation,
634 diag::err_template_instantiate_within_definition)
635 << /*implicit|explicit*/(TSK != TSK_ImplicitInstantiation)
637 // Not much point in noting the template declaration here, since
638 // we're lexically inside it.
639 Instantiation->setInvalidDecl();
640 } else if (InstantiatedFromMember) {
641 if (isa<FunctionDecl>(Instantiation)) {
642 Diag(PointOfInstantiation,
643 diag::err_explicit_instantiation_undefined_member)
644 << /*member function*/ 1 << Instantiation->getDeclName()
645 << Instantiation->getDeclContext();
646 Note = diag::note_explicit_instantiation_here;
648 assert(isa<TagDecl>(Instantiation) && "Must be a TagDecl!");
649 Diag(PointOfInstantiation,
650 diag::err_implicit_instantiate_member_undefined)
652 Note = diag::note_member_declared_at;
655 if (isa<FunctionDecl>(Instantiation)) {
656 Diag(PointOfInstantiation,
657 diag::err_explicit_instantiation_undefined_func_template)
659 Note = diag::note_explicit_instantiation_here;
660 } else if (isa<TagDecl>(Instantiation)) {
661 Diag(PointOfInstantiation, diag::err_template_instantiate_undefined)
662 << (TSK != TSK_ImplicitInstantiation)
664 Note = diag::note_template_decl_here;
666 assert(isa<VarDecl>(Instantiation) && "Must be a VarDecl!");
667 if (isa<VarTemplateSpecializationDecl>(Instantiation)) {
668 Diag(PointOfInstantiation,
669 diag::err_explicit_instantiation_undefined_var_template)
671 Instantiation->setInvalidDecl();
673 Diag(PointOfInstantiation,
674 diag::err_explicit_instantiation_undefined_member)
675 << /*static data member*/ 2 << Instantiation->getDeclName()
676 << Instantiation->getDeclContext();
677 Note = diag::note_explicit_instantiation_here;
680 if (Note) // Diagnostics were emitted.
681 Diag(Pattern->getLocation(), Note.getValue());
683 // In general, Instantiation isn't marked invalid to get more than one
684 // error for multiple undefined instantiations. But the code that does
685 // explicit declaration -> explicit definition conversion can't handle
686 // invalid declarations, so mark as invalid in that case.
687 if (TSK == TSK_ExplicitInstantiationDeclaration)
688 Instantiation->setInvalidDecl();
692 /// DiagnoseTemplateParameterShadow - Produce a diagnostic complaining
693 /// that the template parameter 'PrevDecl' is being shadowed by a new
694 /// declaration at location Loc. Returns true to indicate that this is
695 /// an error, and false otherwise.
696 void Sema::DiagnoseTemplateParameterShadow(SourceLocation Loc, Decl *PrevDecl) {
697 assert(PrevDecl->isTemplateParameter() && "Not a template parameter");
699 // Microsoft Visual C++ permits template parameters to be shadowed.
700 if (getLangOpts().MicrosoftExt)
703 // C++ [temp.local]p4:
704 // A template-parameter shall not be redeclared within its
705 // scope (including nested scopes).
706 Diag(Loc, diag::err_template_param_shadow)
707 << cast<NamedDecl>(PrevDecl)->getDeclName();
708 Diag(PrevDecl->getLocation(), diag::note_template_param_here);
711 /// AdjustDeclIfTemplate - If the given decl happens to be a template, reset
712 /// the parameter D to reference the templated declaration and return a pointer
713 /// to the template declaration. Otherwise, do nothing to D and return null.
714 TemplateDecl *Sema::AdjustDeclIfTemplate(Decl *&D) {
715 if (TemplateDecl *Temp = dyn_cast_or_null<TemplateDecl>(D)) {
716 D = Temp->getTemplatedDecl();
722 ParsedTemplateArgument ParsedTemplateArgument::getTemplatePackExpansion(
723 SourceLocation EllipsisLoc) const {
724 assert(Kind == Template &&
725 "Only template template arguments can be pack expansions here");
726 assert(getAsTemplate().get().containsUnexpandedParameterPack() &&
727 "Template template argument pack expansion without packs");
728 ParsedTemplateArgument Result(*this);
729 Result.EllipsisLoc = EllipsisLoc;
733 static TemplateArgumentLoc translateTemplateArgument(Sema &SemaRef,
734 const ParsedTemplateArgument &Arg) {
736 switch (Arg.getKind()) {
737 case ParsedTemplateArgument::Type: {
739 QualType T = SemaRef.GetTypeFromParser(Arg.getAsType(), &DI);
741 DI = SemaRef.Context.getTrivialTypeSourceInfo(T, Arg.getLocation());
742 return TemplateArgumentLoc(TemplateArgument(T), DI);
745 case ParsedTemplateArgument::NonType: {
746 Expr *E = static_cast<Expr *>(Arg.getAsExpr());
747 return TemplateArgumentLoc(TemplateArgument(E), E);
750 case ParsedTemplateArgument::Template: {
751 TemplateName Template = Arg.getAsTemplate().get();
752 TemplateArgument TArg;
753 if (Arg.getEllipsisLoc().isValid())
754 TArg = TemplateArgument(Template, Optional<unsigned int>());
757 return TemplateArgumentLoc(TArg,
758 Arg.getScopeSpec().getWithLocInContext(
761 Arg.getEllipsisLoc());
765 llvm_unreachable("Unhandled parsed template argument");
768 /// \brief Translates template arguments as provided by the parser
769 /// into template arguments used by semantic analysis.
770 void Sema::translateTemplateArguments(const ASTTemplateArgsPtr &TemplateArgsIn,
771 TemplateArgumentListInfo &TemplateArgs) {
772 for (unsigned I = 0, Last = TemplateArgsIn.size(); I != Last; ++I)
773 TemplateArgs.addArgument(translateTemplateArgument(*this,
777 static void maybeDiagnoseTemplateParameterShadow(Sema &SemaRef, Scope *S,
779 IdentifierInfo *Name) {
780 NamedDecl *PrevDecl = SemaRef.LookupSingleName(
781 S, Name, Loc, Sema::LookupOrdinaryName, Sema::ForRedeclaration);
782 if (PrevDecl && PrevDecl->isTemplateParameter())
783 SemaRef.DiagnoseTemplateParameterShadow(Loc, PrevDecl);
786 /// ActOnTypeParameter - Called when a C++ template type parameter
787 /// (e.g., "typename T") has been parsed. Typename specifies whether
788 /// the keyword "typename" was used to declare the type parameter
789 /// (otherwise, "class" was used), and KeyLoc is the location of the
790 /// "class" or "typename" keyword. ParamName is the name of the
791 /// parameter (NULL indicates an unnamed template parameter) and
792 /// ParamNameLoc is the location of the parameter name (if any).
793 /// If the type parameter has a default argument, it will be added
794 /// later via ActOnTypeParameterDefault.
795 Decl *Sema::ActOnTypeParameter(Scope *S, bool Typename,
796 SourceLocation EllipsisLoc,
797 SourceLocation KeyLoc,
798 IdentifierInfo *ParamName,
799 SourceLocation ParamNameLoc,
800 unsigned Depth, unsigned Position,
801 SourceLocation EqualLoc,
802 ParsedType DefaultArg) {
803 assert(S->isTemplateParamScope() &&
804 "Template type parameter not in template parameter scope!");
806 SourceLocation Loc = ParamNameLoc;
810 bool IsParameterPack = EllipsisLoc.isValid();
811 TemplateTypeParmDecl *Param
812 = TemplateTypeParmDecl::Create(Context, Context.getTranslationUnitDecl(),
813 KeyLoc, Loc, Depth, Position, ParamName,
814 Typename, IsParameterPack);
815 Param->setAccess(AS_public);
818 maybeDiagnoseTemplateParameterShadow(*this, S, ParamNameLoc, ParamName);
820 // Add the template parameter into the current scope.
822 IdResolver.AddDecl(Param);
825 // C++0x [temp.param]p9:
826 // A default template-argument may be specified for any kind of
827 // template-parameter that is not a template parameter pack.
828 if (DefaultArg && IsParameterPack) {
829 Diag(EqualLoc, diag::err_template_param_pack_default_arg);
830 DefaultArg = nullptr;
833 // Handle the default argument, if provided.
835 TypeSourceInfo *DefaultTInfo;
836 GetTypeFromParser(DefaultArg, &DefaultTInfo);
838 assert(DefaultTInfo && "expected source information for type");
840 // Check for unexpanded parameter packs.
841 if (DiagnoseUnexpandedParameterPack(Loc, DefaultTInfo,
842 UPPC_DefaultArgument))
845 // Check the template argument itself.
846 if (CheckTemplateArgument(Param, DefaultTInfo)) {
847 Param->setInvalidDecl();
851 Param->setDefaultArgument(DefaultTInfo);
857 /// \brief Check that the type of a non-type template parameter is
860 /// \returns the (possibly-promoted) parameter type if valid;
861 /// otherwise, produces a diagnostic and returns a NULL type.
862 QualType Sema::CheckNonTypeTemplateParameterType(TypeSourceInfo *&TSI,
863 SourceLocation Loc) {
864 if (TSI->getType()->isUndeducedType()) {
865 // C++1z [temp.dep.expr]p3:
866 // An id-expression is type-dependent if it contains
867 // - an identifier associated by name lookup with a non-type
868 // template-parameter declared with a type that contains a
869 // placeholder type (7.1.7.4),
870 TSI = SubstAutoTypeSourceInfo(TSI, Context.DependentTy);
873 return CheckNonTypeTemplateParameterType(TSI->getType(), Loc);
876 QualType Sema::CheckNonTypeTemplateParameterType(QualType T,
877 SourceLocation Loc) {
878 // We don't allow variably-modified types as the type of non-type template
880 if (T->isVariablyModifiedType()) {
881 Diag(Loc, diag::err_variably_modified_nontype_template_param)
886 // C++ [temp.param]p4:
888 // A non-type template-parameter shall have one of the following
889 // (optionally cv-qualified) types:
891 // -- integral or enumeration type,
892 if (T->isIntegralOrEnumerationType() ||
893 // -- pointer to object or pointer to function,
894 T->isPointerType() ||
895 // -- reference to object or reference to function,
896 T->isReferenceType() ||
897 // -- pointer to member,
898 T->isMemberPointerType() ||
899 // -- std::nullptr_t.
900 T->isNullPtrType() ||
901 // If T is a dependent type, we can't do the check now, so we
902 // assume that it is well-formed.
903 T->isDependentType() ||
904 // Allow use of auto in template parameter declarations.
905 T->isUndeducedType()) {
906 // C++ [temp.param]p5: The top-level cv-qualifiers on the template-parameter
907 // are ignored when determining its type.
908 return T.getUnqualifiedType();
911 // C++ [temp.param]p8:
913 // A non-type template-parameter of type "array of T" or
914 // "function returning T" is adjusted to be of type "pointer to
915 // T" or "pointer to function returning T", respectively.
916 else if (T->isArrayType() || T->isFunctionType())
917 return Context.getDecayedType(T);
919 Diag(Loc, diag::err_template_nontype_parm_bad_type)
925 Decl *Sema::ActOnNonTypeTemplateParameter(Scope *S, Declarator &D,
928 SourceLocation EqualLoc,
930 TypeSourceInfo *TInfo = GetTypeForDeclarator(D, S);
932 if (TInfo->getType()->isUndeducedType()) {
933 Diag(D.getIdentifierLoc(),
934 diag::warn_cxx14_compat_template_nontype_parm_auto_type)
935 << QualType(TInfo->getType()->getContainedAutoType(), 0);
938 assert(S->isTemplateParamScope() &&
939 "Non-type template parameter not in template parameter scope!");
940 bool Invalid = false;
942 QualType T = CheckNonTypeTemplateParameterType(TInfo, D.getIdentifierLoc());
944 T = Context.IntTy; // Recover with an 'int' type.
948 IdentifierInfo *ParamName = D.getIdentifier();
949 bool IsParameterPack = D.hasEllipsis();
950 NonTypeTemplateParmDecl *Param
951 = NonTypeTemplateParmDecl::Create(Context, Context.getTranslationUnitDecl(),
953 D.getIdentifierLoc(),
954 Depth, Position, ParamName, T,
955 IsParameterPack, TInfo);
956 Param->setAccess(AS_public);
959 Param->setInvalidDecl();
962 maybeDiagnoseTemplateParameterShadow(*this, S, D.getIdentifierLoc(),
965 // Add the template parameter into the current scope.
967 IdResolver.AddDecl(Param);
970 // C++0x [temp.param]p9:
971 // A default template-argument may be specified for any kind of
972 // template-parameter that is not a template parameter pack.
973 if (Default && IsParameterPack) {
974 Diag(EqualLoc, diag::err_template_param_pack_default_arg);
978 // Check the well-formedness of the default template argument, if provided.
980 // Check for unexpanded parameter packs.
981 if (DiagnoseUnexpandedParameterPack(Default, UPPC_DefaultArgument))
984 TemplateArgument Converted;
985 ExprResult DefaultRes =
986 CheckTemplateArgument(Param, Param->getType(), Default, Converted);
987 if (DefaultRes.isInvalid()) {
988 Param->setInvalidDecl();
991 Default = DefaultRes.get();
993 Param->setDefaultArgument(Default);
999 /// ActOnTemplateTemplateParameter - Called when a C++ template template
1000 /// parameter (e.g. T in template <template \<typename> class T> class array)
1001 /// has been parsed. S is the current scope.
1002 Decl *Sema::ActOnTemplateTemplateParameter(Scope* S,
1003 SourceLocation TmpLoc,
1004 TemplateParameterList *Params,
1005 SourceLocation EllipsisLoc,
1006 IdentifierInfo *Name,
1007 SourceLocation NameLoc,
1010 SourceLocation EqualLoc,
1011 ParsedTemplateArgument Default) {
1012 assert(S->isTemplateParamScope() &&
1013 "Template template parameter not in template parameter scope!");
1015 // Construct the parameter object.
1016 bool IsParameterPack = EllipsisLoc.isValid();
1017 TemplateTemplateParmDecl *Param =
1018 TemplateTemplateParmDecl::Create(Context, Context.getTranslationUnitDecl(),
1019 NameLoc.isInvalid()? TmpLoc : NameLoc,
1020 Depth, Position, IsParameterPack,
1022 Param->setAccess(AS_public);
1024 // If the template template parameter has a name, then link the identifier
1025 // into the scope and lookup mechanisms.
1027 maybeDiagnoseTemplateParameterShadow(*this, S, NameLoc, Name);
1030 IdResolver.AddDecl(Param);
1033 if (Params->size() == 0) {
1034 Diag(Param->getLocation(), diag::err_template_template_parm_no_parms)
1035 << SourceRange(Params->getLAngleLoc(), Params->getRAngleLoc());
1036 Param->setInvalidDecl();
1039 // C++0x [temp.param]p9:
1040 // A default template-argument may be specified for any kind of
1041 // template-parameter that is not a template parameter pack.
1042 if (IsParameterPack && !Default.isInvalid()) {
1043 Diag(EqualLoc, diag::err_template_param_pack_default_arg);
1044 Default = ParsedTemplateArgument();
1047 if (!Default.isInvalid()) {
1048 // Check only that we have a template template argument. We don't want to
1049 // try to check well-formedness now, because our template template parameter
1050 // might have dependent types in its template parameters, which we wouldn't
1051 // be able to match now.
1053 // If none of the template template parameter's template arguments mention
1054 // other template parameters, we could actually perform more checking here.
1055 // However, it isn't worth doing.
1056 TemplateArgumentLoc DefaultArg = translateTemplateArgument(*this, Default);
1057 if (DefaultArg.getArgument().getAsTemplate().isNull()) {
1058 Diag(DefaultArg.getLocation(), diag::err_template_arg_not_valid_template)
1059 << DefaultArg.getSourceRange();
1063 // Check for unexpanded parameter packs.
1064 if (DiagnoseUnexpandedParameterPack(DefaultArg.getLocation(),
1065 DefaultArg.getArgument().getAsTemplate(),
1066 UPPC_DefaultArgument))
1069 Param->setDefaultArgument(Context, DefaultArg);
1075 /// ActOnTemplateParameterList - Builds a TemplateParameterList, optionally
1076 /// constrained by RequiresClause, that contains the template parameters in
1078 TemplateParameterList *
1079 Sema::ActOnTemplateParameterList(unsigned Depth,
1080 SourceLocation ExportLoc,
1081 SourceLocation TemplateLoc,
1082 SourceLocation LAngleLoc,
1083 ArrayRef<Decl *> Params,
1084 SourceLocation RAngleLoc,
1085 Expr *RequiresClause) {
1086 if (ExportLoc.isValid())
1087 Diag(ExportLoc, diag::warn_template_export_unsupported);
1089 return TemplateParameterList::Create(
1090 Context, TemplateLoc, LAngleLoc,
1091 llvm::makeArrayRef((NamedDecl *const *)Params.data(), Params.size()),
1092 RAngleLoc, RequiresClause);
1095 static void SetNestedNameSpecifier(TagDecl *T, const CXXScopeSpec &SS) {
1097 T->setQualifierInfo(SS.getWithLocInContext(T->getASTContext()));
1101 Sema::CheckClassTemplate(Scope *S, unsigned TagSpec, TagUseKind TUK,
1102 SourceLocation KWLoc, CXXScopeSpec &SS,
1103 IdentifierInfo *Name, SourceLocation NameLoc,
1104 AttributeList *Attr,
1105 TemplateParameterList *TemplateParams,
1106 AccessSpecifier AS, SourceLocation ModulePrivateLoc,
1107 SourceLocation FriendLoc,
1108 unsigned NumOuterTemplateParamLists,
1109 TemplateParameterList** OuterTemplateParamLists,
1110 SkipBodyInfo *SkipBody) {
1111 assert(TemplateParams && TemplateParams->size() > 0 &&
1112 "No template parameters");
1113 assert(TUK != TUK_Reference && "Can only declare or define class templates");
1114 bool Invalid = false;
1116 // Check that we can declare a template here.
1117 if (CheckTemplateDeclScope(S, TemplateParams))
1120 TagTypeKind Kind = TypeWithKeyword::getTagTypeKindForTypeSpec(TagSpec);
1121 assert(Kind != TTK_Enum && "can't build template of enumerated type");
1123 // There is no such thing as an unnamed class template.
1125 Diag(KWLoc, diag::err_template_unnamed_class);
1129 // Find any previous declaration with this name. For a friend with no
1130 // scope explicitly specified, we only look for tag declarations (per
1131 // C++11 [basic.lookup.elab]p2).
1132 DeclContext *SemanticContext;
1133 LookupResult Previous(*this, Name, NameLoc,
1134 (SS.isEmpty() && TUK == TUK_Friend)
1135 ? LookupTagName : LookupOrdinaryName,
1137 if (SS.isNotEmpty() && !SS.isInvalid()) {
1138 SemanticContext = computeDeclContext(SS, true);
1139 if (!SemanticContext) {
1140 // FIXME: Horrible, horrible hack! We can't currently represent this
1141 // in the AST, and historically we have just ignored such friend
1142 // class templates, so don't complain here.
1143 Diag(NameLoc, TUK == TUK_Friend
1144 ? diag::warn_template_qualified_friend_ignored
1145 : diag::err_template_qualified_declarator_no_match)
1146 << SS.getScopeRep() << SS.getRange();
1147 return TUK != TUK_Friend;
1150 if (RequireCompleteDeclContext(SS, SemanticContext))
1153 // If we're adding a template to a dependent context, we may need to
1154 // rebuilding some of the types used within the template parameter list,
1155 // now that we know what the current instantiation is.
1156 if (SemanticContext->isDependentContext()) {
1157 ContextRAII SavedContext(*this, SemanticContext);
1158 if (RebuildTemplateParamsInCurrentInstantiation(TemplateParams))
1160 } else if (TUK != TUK_Friend && TUK != TUK_Reference)
1161 diagnoseQualifiedDeclaration(SS, SemanticContext, Name, NameLoc);
1163 LookupQualifiedName(Previous, SemanticContext);
1165 SemanticContext = CurContext;
1167 // C++14 [class.mem]p14:
1168 // If T is the name of a class, then each of the following shall have a
1169 // name different from T:
1170 // -- every member template of class T
1171 if (TUK != TUK_Friend &&
1172 DiagnoseClassNameShadow(SemanticContext,
1173 DeclarationNameInfo(Name, NameLoc)))
1176 LookupName(Previous, S);
1179 if (Previous.isAmbiguous())
1182 NamedDecl *PrevDecl = nullptr;
1183 if (Previous.begin() != Previous.end())
1184 PrevDecl = (*Previous.begin())->getUnderlyingDecl();
1186 if (PrevDecl && PrevDecl->isTemplateParameter()) {
1187 // Maybe we will complain about the shadowed template parameter.
1188 DiagnoseTemplateParameterShadow(NameLoc, PrevDecl);
1189 // Just pretend that we didn't see the previous declaration.
1193 // If there is a previous declaration with the same name, check
1194 // whether this is a valid redeclaration.
1195 ClassTemplateDecl *PrevClassTemplate
1196 = dyn_cast_or_null<ClassTemplateDecl>(PrevDecl);
1198 // We may have found the injected-class-name of a class template,
1199 // class template partial specialization, or class template specialization.
1200 // In these cases, grab the template that is being defined or specialized.
1201 if (!PrevClassTemplate && PrevDecl && isa<CXXRecordDecl>(PrevDecl) &&
1202 cast<CXXRecordDecl>(PrevDecl)->isInjectedClassName()) {
1203 PrevDecl = cast<CXXRecordDecl>(PrevDecl->getDeclContext());
1205 = cast<CXXRecordDecl>(PrevDecl)->getDescribedClassTemplate();
1206 if (!PrevClassTemplate && isa<ClassTemplateSpecializationDecl>(PrevDecl)) {
1208 = cast<ClassTemplateSpecializationDecl>(PrevDecl)
1209 ->getSpecializedTemplate();
1213 if (TUK == TUK_Friend) {
1214 // C++ [namespace.memdef]p3:
1215 // [...] When looking for a prior declaration of a class or a function
1216 // declared as a friend, and when the name of the friend class or
1217 // function is neither a qualified name nor a template-id, scopes outside
1218 // the innermost enclosing namespace scope are not considered.
1220 DeclContext *OutermostContext = CurContext;
1221 while (!OutermostContext->isFileContext())
1222 OutermostContext = OutermostContext->getLookupParent();
1225 (OutermostContext->Equals(PrevDecl->getDeclContext()) ||
1226 OutermostContext->Encloses(PrevDecl->getDeclContext()))) {
1227 SemanticContext = PrevDecl->getDeclContext();
1229 // Declarations in outer scopes don't matter. However, the outermost
1230 // context we computed is the semantic context for our new
1232 PrevDecl = PrevClassTemplate = nullptr;
1233 SemanticContext = OutermostContext;
1235 // Check that the chosen semantic context doesn't already contain a
1236 // declaration of this name as a non-tag type.
1237 Previous.clear(LookupOrdinaryName);
1238 DeclContext *LookupContext = SemanticContext;
1239 while (LookupContext->isTransparentContext())
1240 LookupContext = LookupContext->getLookupParent();
1241 LookupQualifiedName(Previous, LookupContext);
1243 if (Previous.isAmbiguous())
1246 if (Previous.begin() != Previous.end())
1247 PrevDecl = (*Previous.begin())->getUnderlyingDecl();
1250 } else if (PrevDecl &&
1251 !isDeclInScope(Previous.getRepresentativeDecl(), SemanticContext,
1253 PrevDecl = PrevClassTemplate = nullptr;
1255 if (auto *Shadow = dyn_cast_or_null<UsingShadowDecl>(
1256 PrevDecl ? Previous.getRepresentativeDecl() : nullptr)) {
1258 !(PrevClassTemplate &&
1259 PrevClassTemplate->getDeclContext()->getRedeclContext()->Equals(
1260 SemanticContext->getRedeclContext()))) {
1261 Diag(KWLoc, diag::err_using_decl_conflict_reverse);
1262 Diag(Shadow->getTargetDecl()->getLocation(),
1263 diag::note_using_decl_target);
1264 Diag(Shadow->getUsingDecl()->getLocation(), diag::note_using_decl) << 0;
1265 // Recover by ignoring the old declaration.
1266 PrevDecl = PrevClassTemplate = nullptr;
1270 // TODO Memory management; associated constraints are not always stored.
1271 Expr *const CurAC = formAssociatedConstraints(TemplateParams, nullptr);
1273 if (PrevClassTemplate) {
1274 // Ensure that the template parameter lists are compatible. Skip this check
1275 // for a friend in a dependent context: the template parameter list itself
1276 // could be dependent.
1277 if (!(TUK == TUK_Friend && CurContext->isDependentContext()) &&
1278 !TemplateParameterListsAreEqual(TemplateParams,
1279 PrevClassTemplate->getTemplateParameters(),
1284 // Check for matching associated constraints on redeclarations.
1285 const Expr *const PrevAC = PrevClassTemplate->getAssociatedConstraints();
1286 const bool RedeclACMismatch = [&] {
1287 if (!(CurAC || PrevAC))
1288 return false; // Nothing to check; no mismatch.
1289 if (CurAC && PrevAC) {
1290 llvm::FoldingSetNodeID CurACInfo, PrevACInfo;
1291 CurAC->Profile(CurACInfo, Context, /*Canonical=*/true);
1292 PrevAC->Profile(PrevACInfo, Context, /*Canonical=*/true);
1293 if (CurACInfo == PrevACInfo)
1294 return false; // All good; no mismatch.
1299 if (RedeclACMismatch) {
1300 Diag(CurAC ? CurAC->getLocStart() : NameLoc,
1301 diag::err_template_different_associated_constraints);
1302 Diag(PrevAC ? PrevAC->getLocStart() : PrevClassTemplate->getLocation(),
1303 diag::note_template_prev_declaration) << /*declaration*/0;
1307 // C++ [temp.class]p4:
1308 // In a redeclaration, partial specialization, explicit
1309 // specialization or explicit instantiation of a class template,
1310 // the class-key shall agree in kind with the original class
1311 // template declaration (7.1.5.3).
1312 RecordDecl *PrevRecordDecl = PrevClassTemplate->getTemplatedDecl();
1313 if (!isAcceptableTagRedeclaration(PrevRecordDecl, Kind,
1314 TUK == TUK_Definition, KWLoc, Name)) {
1315 Diag(KWLoc, diag::err_use_with_wrong_tag)
1317 << FixItHint::CreateReplacement(KWLoc, PrevRecordDecl->getKindName());
1318 Diag(PrevRecordDecl->getLocation(), diag::note_previous_use);
1319 Kind = PrevRecordDecl->getTagKind();
1322 // Check for redefinition of this class template.
1323 if (TUK == TUK_Definition) {
1324 if (TagDecl *Def = PrevRecordDecl->getDefinition()) {
1325 // If we have a prior definition that is not visible, treat this as
1326 // simply making that previous definition visible.
1327 NamedDecl *Hidden = nullptr;
1328 if (SkipBody && !hasVisibleDefinition(Def, &Hidden)) {
1329 SkipBody->ShouldSkip = true;
1330 auto *Tmpl = cast<CXXRecordDecl>(Hidden)->getDescribedClassTemplate();
1331 assert(Tmpl && "original definition of a class template is not a "
1333 makeMergedDefinitionVisible(Hidden);
1334 makeMergedDefinitionVisible(Tmpl);
1338 Diag(NameLoc, diag::err_redefinition) << Name;
1339 Diag(Def->getLocation(), diag::note_previous_definition);
1340 // FIXME: Would it make sense to try to "forget" the previous
1341 // definition, as part of error recovery?
1345 } else if (PrevDecl) {
1347 // A class template shall not have the same name as any other
1348 // template, class, function, object, enumeration, enumerator,
1349 // namespace, or type in the same scope (3.3), except as specified
1351 Diag(NameLoc, diag::err_redefinition_different_kind) << Name;
1352 Diag(PrevDecl->getLocation(), diag::note_previous_definition);
1356 // Check the template parameter list of this declaration, possibly
1357 // merging in the template parameter list from the previous class
1358 // template declaration. Skip this check for a friend in a dependent
1359 // context, because the template parameter list might be dependent.
1360 if (!(TUK == TUK_Friend && CurContext->isDependentContext()) &&
1361 CheckTemplateParameterList(
1363 PrevClassTemplate ? PrevClassTemplate->getTemplateParameters()
1365 (SS.isSet() && SemanticContext && SemanticContext->isRecord() &&
1366 SemanticContext->isDependentContext())
1367 ? TPC_ClassTemplateMember
1368 : TUK == TUK_Friend ? TPC_FriendClassTemplate
1369 : TPC_ClassTemplate))
1373 // If the name of the template was qualified, we must be defining the
1374 // template out-of-line.
1375 if (!SS.isInvalid() && !Invalid && !PrevClassTemplate) {
1376 Diag(NameLoc, TUK == TUK_Friend ? diag::err_friend_decl_does_not_match
1377 : diag::err_member_decl_does_not_match)
1378 << Name << SemanticContext << /*IsDefinition*/true << SS.getRange();
1383 // If this is a templated friend in a dependent context we should not put it
1384 // on the redecl chain. In some cases, the templated friend can be the most
1385 // recent declaration tricking the template instantiator to make substitutions
1387 // FIXME: Figure out how to combine with shouldLinkDependentDeclWithPrevious
1388 bool ShouldAddRedecl
1389 = !(TUK == TUK_Friend && CurContext->isDependentContext());
1391 CXXRecordDecl *NewClass =
1392 CXXRecordDecl::Create(Context, Kind, SemanticContext, KWLoc, NameLoc, Name,
1393 PrevClassTemplate && ShouldAddRedecl ?
1394 PrevClassTemplate->getTemplatedDecl() : nullptr,
1395 /*DelayTypeCreation=*/true);
1396 SetNestedNameSpecifier(NewClass, SS);
1397 if (NumOuterTemplateParamLists > 0)
1398 NewClass->setTemplateParameterListsInfo(
1399 Context, llvm::makeArrayRef(OuterTemplateParamLists,
1400 NumOuterTemplateParamLists));
1402 // Add alignment attributes if necessary; these attributes are checked when
1403 // the ASTContext lays out the structure.
1404 if (TUK == TUK_Definition) {
1405 AddAlignmentAttributesForRecord(NewClass);
1406 AddMsStructLayoutForRecord(NewClass);
1409 // Attach the associated constraints when the declaration will not be part of
1411 Expr *const ACtoAttach =
1412 PrevClassTemplate && ShouldAddRedecl ? nullptr : CurAC;
1414 ClassTemplateDecl *NewTemplate
1415 = ClassTemplateDecl::Create(Context, SemanticContext, NameLoc,
1416 DeclarationName(Name), TemplateParams,
1417 NewClass, ACtoAttach);
1419 if (ShouldAddRedecl)
1420 NewTemplate->setPreviousDecl(PrevClassTemplate);
1422 NewClass->setDescribedClassTemplate(NewTemplate);
1424 if (ModulePrivateLoc.isValid())
1425 NewTemplate->setModulePrivate();
1427 // Build the type for the class template declaration now.
1428 QualType T = NewTemplate->getInjectedClassNameSpecialization();
1429 T = Context.getInjectedClassNameType(NewClass, T);
1430 assert(T->isDependentType() && "Class template type is not dependent?");
1433 // If we are providing an explicit specialization of a member that is a
1434 // class template, make a note of that.
1435 if (PrevClassTemplate &&
1436 PrevClassTemplate->getInstantiatedFromMemberTemplate())
1437 PrevClassTemplate->setMemberSpecialization();
1439 // Set the access specifier.
1440 if (!Invalid && TUK != TUK_Friend && NewTemplate->getDeclContext()->isRecord())
1441 SetMemberAccessSpecifier(NewTemplate, PrevClassTemplate, AS);
1443 // Set the lexical context of these templates
1444 NewClass->setLexicalDeclContext(CurContext);
1445 NewTemplate->setLexicalDeclContext(CurContext);
1447 if (TUK == TUK_Definition)
1448 NewClass->startDefinition();
1451 ProcessDeclAttributeList(S, NewClass, Attr);
1453 if (PrevClassTemplate)
1454 mergeDeclAttributes(NewClass, PrevClassTemplate->getTemplatedDecl());
1456 AddPushedVisibilityAttribute(NewClass);
1458 if (TUK != TUK_Friend) {
1459 // Per C++ [basic.scope.temp]p2, skip the template parameter scopes.
1461 while ((Outer->getFlags() & Scope::TemplateParamScope) != 0)
1462 Outer = Outer->getParent();
1463 PushOnScopeChains(NewTemplate, Outer);
1465 if (PrevClassTemplate && PrevClassTemplate->getAccess() != AS_none) {
1466 NewTemplate->setAccess(PrevClassTemplate->getAccess());
1467 NewClass->setAccess(PrevClassTemplate->getAccess());
1470 NewTemplate->setObjectOfFriendDecl();
1472 // Friend templates are visible in fairly strange ways.
1473 if (!CurContext->isDependentContext()) {
1474 DeclContext *DC = SemanticContext->getRedeclContext();
1475 DC->makeDeclVisibleInContext(NewTemplate);
1476 if (Scope *EnclosingScope = getScopeForDeclContext(S, DC))
1477 PushOnScopeChains(NewTemplate, EnclosingScope,
1478 /* AddToContext = */ false);
1481 FriendDecl *Friend = FriendDecl::Create(
1482 Context, CurContext, NewClass->getLocation(), NewTemplate, FriendLoc);
1483 Friend->setAccess(AS_public);
1484 CurContext->addDecl(Friend);
1488 NewTemplate->setInvalidDecl();
1489 NewClass->setInvalidDecl();
1492 ActOnDocumentableDecl(NewTemplate);
1498 /// Transform to convert portions of a constructor declaration into the
1499 /// corresponding deduction guide, per C++1z [over.match.class.deduct]p1.
1500 struct ConvertConstructorToDeductionGuideTransform {
1501 ConvertConstructorToDeductionGuideTransform(Sema &S,
1502 ClassTemplateDecl *Template)
1503 : SemaRef(S), Template(Template) {}
1506 ClassTemplateDecl *Template;
1508 DeclContext *DC = Template->getDeclContext();
1509 CXXRecordDecl *Primary = Template->getTemplatedDecl();
1510 DeclarationName DeductionGuideName =
1511 SemaRef.Context.DeclarationNames.getCXXDeductionGuideName(Template);
1513 QualType DeducedType = SemaRef.Context.getTypeDeclType(Primary);
1515 // Index adjustment to apply to convert depth-1 template parameters into
1516 // depth-0 template parameters.
1517 unsigned Depth1IndexAdjustment = Template->getTemplateParameters()->size();
1519 /// Transform a constructor declaration into a deduction guide.
1520 NamedDecl *transformConstructor(FunctionTemplateDecl *FTD,
1521 CXXConstructorDecl *CD) {
1522 SmallVector<TemplateArgument, 16> SubstArgs;
1524 LocalInstantiationScope Scope(SemaRef);
1526 // C++ [over.match.class.deduct]p1:
1527 // -- For each constructor of the class template designated by the
1528 // template-name, a function template with the following properties:
1530 // -- The template parameters are the template parameters of the class
1531 // template followed by the template parameters (including default
1532 // template arguments) of the constructor, if any.
1533 TemplateParameterList *TemplateParams = Template->getTemplateParameters();
1535 TemplateParameterList *InnerParams = FTD->getTemplateParameters();
1536 SmallVector<NamedDecl *, 16> AllParams;
1537 AllParams.reserve(TemplateParams->size() + InnerParams->size());
1538 AllParams.insert(AllParams.begin(),
1539 TemplateParams->begin(), TemplateParams->end());
1540 SubstArgs.reserve(InnerParams->size());
1542 // Later template parameters could refer to earlier ones, so build up
1543 // a list of substituted template arguments as we go.
1544 for (NamedDecl *Param : *InnerParams) {
1545 MultiLevelTemplateArgumentList Args;
1546 Args.addOuterTemplateArguments(SubstArgs);
1547 Args.addOuterRetainedLevel();
1548 NamedDecl *NewParam = transformTemplateParameter(Param, Args);
1551 AllParams.push_back(NewParam);
1552 SubstArgs.push_back(SemaRef.Context.getCanonicalTemplateArgument(
1553 SemaRef.Context.getInjectedTemplateArg(NewParam)));
1555 TemplateParams = TemplateParameterList::Create(
1556 SemaRef.Context, InnerParams->getTemplateLoc(),
1557 InnerParams->getLAngleLoc(), AllParams, InnerParams->getRAngleLoc(),
1558 /*FIXME: RequiresClause*/ nullptr);
1561 // If we built a new template-parameter-list, track that we need to
1562 // substitute references to the old parameters into references to the
1564 MultiLevelTemplateArgumentList Args;
1566 Args.addOuterTemplateArguments(SubstArgs);
1567 Args.addOuterRetainedLevel();
1570 FunctionProtoTypeLoc FPTL = CD->getTypeSourceInfo()->getTypeLoc()
1571 .getAsAdjusted<FunctionProtoTypeLoc>();
1572 assert(FPTL && "no prototype for constructor declaration");
1574 // Transform the type of the function, adjusting the return type and
1575 // replacing references to the old parameters with references to the
1578 SmallVector<ParmVarDecl*, 8> Params;
1579 QualType NewType = transformFunctionProtoType(TLB, FPTL, Params, Args);
1580 if (NewType.isNull())
1582 TypeSourceInfo *NewTInfo = TLB.getTypeSourceInfo(SemaRef.Context, NewType);
1584 return buildDeductionGuide(TemplateParams, CD->isExplicit(), NewTInfo,
1585 CD->getLocStart(), CD->getLocation(),
1589 /// Build a deduction guide with the specified parameter types.
1590 NamedDecl *buildSimpleDeductionGuide(MutableArrayRef<QualType> ParamTypes) {
1591 SourceLocation Loc = Template->getLocation();
1593 // Build the requested type.
1594 FunctionProtoType::ExtProtoInfo EPI;
1595 EPI.HasTrailingReturn = true;
1596 QualType Result = SemaRef.BuildFunctionType(DeducedType, ParamTypes, Loc,
1597 DeductionGuideName, EPI);
1598 TypeSourceInfo *TSI = SemaRef.Context.getTrivialTypeSourceInfo(Result, Loc);
1600 FunctionProtoTypeLoc FPTL =
1601 TSI->getTypeLoc().castAs<FunctionProtoTypeLoc>();
1603 // Build the parameters, needed during deduction / substitution.
1604 SmallVector<ParmVarDecl*, 4> Params;
1605 for (auto T : ParamTypes) {
1606 ParmVarDecl *NewParam = ParmVarDecl::Create(
1607 SemaRef.Context, DC, Loc, Loc, nullptr, T,
1608 SemaRef.Context.getTrivialTypeSourceInfo(T, Loc), SC_None, nullptr);
1609 NewParam->setScopeInfo(0, Params.size());
1610 FPTL.setParam(Params.size(), NewParam);
1611 Params.push_back(NewParam);
1614 return buildDeductionGuide(Template->getTemplateParameters(), false, TSI,
1619 /// Transform a constructor template parameter into a deduction guide template
1620 /// parameter, rebuilding any internal references to earlier parameters and
1621 /// renumbering as we go.
1622 NamedDecl *transformTemplateParameter(NamedDecl *TemplateParam,
1623 MultiLevelTemplateArgumentList &Args) {
1624 if (auto *TTP = dyn_cast<TemplateTypeParmDecl>(TemplateParam)) {
1625 // TemplateTypeParmDecl's index cannot be changed after creation, so
1626 // substitute it directly.
1627 auto *NewTTP = TemplateTypeParmDecl::Create(
1628 SemaRef.Context, DC, TTP->getLocStart(), TTP->getLocation(),
1629 /*Depth*/0, Depth1IndexAdjustment + TTP->getIndex(),
1630 TTP->getIdentifier(), TTP->wasDeclaredWithTypename(),
1631 TTP->isParameterPack());
1632 if (TTP->hasDefaultArgument()) {
1633 TypeSourceInfo *InstantiatedDefaultArg =
1634 SemaRef.SubstType(TTP->getDefaultArgumentInfo(), Args,
1635 TTP->getDefaultArgumentLoc(), TTP->getDeclName());
1636 if (InstantiatedDefaultArg)
1637 NewTTP->setDefaultArgument(InstantiatedDefaultArg);
1639 SemaRef.CurrentInstantiationScope->InstantiatedLocal(TemplateParam,
1644 if (auto *TTP = dyn_cast<TemplateTemplateParmDecl>(TemplateParam))
1645 return transformTemplateParameterImpl(TTP, Args);
1647 return transformTemplateParameterImpl(
1648 cast<NonTypeTemplateParmDecl>(TemplateParam), Args);
1650 template<typename TemplateParmDecl>
1652 transformTemplateParameterImpl(TemplateParmDecl *OldParam,
1653 MultiLevelTemplateArgumentList &Args) {
1654 // Ask the template instantiator to do the heavy lifting for us, then adjust
1655 // the index of the parameter once it's done.
1657 cast_or_null<TemplateParmDecl>(SemaRef.SubstDecl(OldParam, DC, Args));
1658 assert(NewParam->getDepth() == 0 && "unexpected template param depth");
1659 NewParam->setPosition(NewParam->getPosition() + Depth1IndexAdjustment);
1663 QualType transformFunctionProtoType(TypeLocBuilder &TLB,
1664 FunctionProtoTypeLoc TL,
1665 SmallVectorImpl<ParmVarDecl*> &Params,
1666 MultiLevelTemplateArgumentList &Args) {
1667 SmallVector<QualType, 4> ParamTypes;
1668 const FunctionProtoType *T = TL.getTypePtr();
1670 // -- The types of the function parameters are those of the constructor.
1671 for (auto *OldParam : TL.getParams()) {
1672 ParmVarDecl *NewParam = transformFunctionTypeParam(OldParam, Args);
1675 ParamTypes.push_back(NewParam->getType());
1676 Params.push_back(NewParam);
1679 // -- The return type is the class template specialization designated by
1680 // the template-name and template arguments corresponding to the
1681 // template parameters obtained from the class template.
1683 // We use the injected-class-name type of the primary template instead.
1684 // This has the convenient property that it is different from any type that
1685 // the user can write in a deduction-guide (because they cannot enter the
1686 // context of the template), so implicit deduction guides can never collide
1687 // with explicit ones.
1688 QualType ReturnType = DeducedType;
1689 TLB.pushTypeSpec(ReturnType).setNameLoc(Primary->getLocation());
1691 // Resolving a wording defect, we also inherit the variadicness of the
1693 FunctionProtoType::ExtProtoInfo EPI;
1694 EPI.Variadic = T->isVariadic();
1695 EPI.HasTrailingReturn = true;
1697 QualType Result = SemaRef.BuildFunctionType(
1698 ReturnType, ParamTypes, TL.getLocStart(), DeductionGuideName, EPI);
1699 if (Result.isNull())
1702 FunctionProtoTypeLoc NewTL = TLB.push<FunctionProtoTypeLoc>(Result);
1703 NewTL.setLocalRangeBegin(TL.getLocalRangeBegin());
1704 NewTL.setLParenLoc(TL.getLParenLoc());
1705 NewTL.setRParenLoc(TL.getRParenLoc());
1706 NewTL.setExceptionSpecRange(SourceRange());
1707 NewTL.setLocalRangeEnd(TL.getLocalRangeEnd());
1708 for (unsigned I = 0, E = NewTL.getNumParams(); I != E; ++I)
1709 NewTL.setParam(I, Params[I]);
1715 transformFunctionTypeParam(ParmVarDecl *OldParam,
1716 MultiLevelTemplateArgumentList &Args) {
1717 TypeSourceInfo *OldDI = OldParam->getTypeSourceInfo();
1718 TypeSourceInfo *NewDI;
1719 if (!Args.getNumLevels())
1721 else if (auto PackTL = OldDI->getTypeLoc().getAs<PackExpansionTypeLoc>()) {
1722 // Expand out the one and only element in each inner pack.
1723 Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, 0);
1725 SemaRef.SubstType(PackTL.getPatternLoc(), Args,
1726 OldParam->getLocation(), OldParam->getDeclName());
1727 if (!NewDI) return nullptr;
1729 SemaRef.CheckPackExpansion(NewDI, PackTL.getEllipsisLoc(),
1730 PackTL.getTypePtr()->getNumExpansions());
1732 NewDI = SemaRef.SubstType(OldDI, Args, OldParam->getLocation(),
1733 OldParam->getDeclName());
1737 // Canonicalize the type. This (for instance) replaces references to
1738 // typedef members of the current instantiations with the definitions of
1739 // those typedefs, avoiding triggering instantiation of the deduced type
1740 // during deduction.
1741 // FIXME: It would be preferable to retain type sugar and source
1742 // information here (and handle this in substitution instead).
1743 NewDI = SemaRef.Context.getTrivialTypeSourceInfo(
1744 SemaRef.Context.getCanonicalType(NewDI->getType()),
1745 OldParam->getLocation());
1747 // Resolving a wording defect, we also inherit default arguments from the
1749 ExprResult NewDefArg;
1750 if (OldParam->hasDefaultArg()) {
1751 NewDefArg = Args.getNumLevels()
1752 ? SemaRef.SubstExpr(OldParam->getDefaultArg(), Args)
1753 : OldParam->getDefaultArg();
1754 if (NewDefArg.isInvalid())
1758 ParmVarDecl *NewParam = ParmVarDecl::Create(SemaRef.Context, DC,
1759 OldParam->getInnerLocStart(),
1760 OldParam->getLocation(),
1761 OldParam->getIdentifier(),
1764 OldParam->getStorageClass(),
1766 NewParam->setScopeInfo(OldParam->getFunctionScopeDepth(),
1767 OldParam->getFunctionScopeIndex());
1771 NamedDecl *buildDeductionGuide(TemplateParameterList *TemplateParams,
1772 bool Explicit, TypeSourceInfo *TInfo,
1773 SourceLocation LocStart, SourceLocation Loc,
1774 SourceLocation LocEnd) {
1775 DeclarationNameInfo Name(DeductionGuideName, Loc);
1776 ArrayRef<ParmVarDecl *> Params =
1777 TInfo->getTypeLoc().castAs<FunctionProtoTypeLoc>().getParams();
1779 // Build the implicit deduction guide template.
1781 CXXDeductionGuideDecl::Create(SemaRef.Context, DC, LocStart, Explicit,
1782 Name, TInfo->getType(), TInfo, LocEnd);
1783 Guide->setImplicit();
1784 Guide->setParams(Params);
1786 for (auto *Param : Params)
1787 Param->setDeclContext(Guide);
1789 auto *GuideTemplate = FunctionTemplateDecl::Create(
1790 SemaRef.Context, DC, Loc, DeductionGuideName, TemplateParams, Guide);
1791 GuideTemplate->setImplicit();
1792 Guide->setDescribedFunctionTemplate(GuideTemplate);
1794 if (isa<CXXRecordDecl>(DC)) {
1795 Guide->setAccess(AS_public);
1796 GuideTemplate->setAccess(AS_public);
1799 DC->addDecl(GuideTemplate);
1800 return GuideTemplate;
1805 void Sema::DeclareImplicitDeductionGuides(TemplateDecl *Template,
1806 SourceLocation Loc) {
1807 DeclContext *DC = Template->getDeclContext();
1808 if (DC->isDependentContext())
1811 ConvertConstructorToDeductionGuideTransform Transform(
1812 *this, cast<ClassTemplateDecl>(Template));
1813 if (!isCompleteType(Loc, Transform.DeducedType))
1816 // Check whether we've already declared deduction guides for this template.
1817 // FIXME: Consider storing a flag on the template to indicate this.
1818 auto Existing = DC->lookup(Transform.DeductionGuideName);
1819 for (auto *D : Existing)
1820 if (D->isImplicit())
1823 // In case we were expanding a pack when we attempted to declare deduction
1824 // guides, turn off pack expansion for everything we're about to do.
1825 ArgumentPackSubstitutionIndexRAII SubstIndex(*this, -1);
1826 // Create a template instantiation record to track the "instantiation" of
1827 // constructors into deduction guides.
1828 // FIXME: Add a kind for this to give more meaningful diagnostics. But can
1829 // this substitution process actually fail?
1830 InstantiatingTemplate BuildingDeductionGuides(*this, Loc, Template);
1832 // Convert declared constructors into deduction guide templates.
1833 // FIXME: Skip constructors for which deduction must necessarily fail (those
1834 // for which some class template parameter without a default argument never
1835 // appears in a deduced context).
1836 bool AddedAny = false;
1837 bool AddedCopyOrMove = false;
1838 for (NamedDecl *D : LookupConstructors(Transform.Primary)) {
1839 D = D->getUnderlyingDecl();
1840 if (D->isInvalidDecl() || D->isImplicit())
1842 D = cast<NamedDecl>(D->getCanonicalDecl());
1844 auto *FTD = dyn_cast<FunctionTemplateDecl>(D);
1846 dyn_cast_or_null<CXXConstructorDecl>(FTD ? FTD->getTemplatedDecl() : D);
1847 // Class-scope explicit specializations (MS extension) do not result in
1848 // deduction guides.
1849 if (!CD || (!FTD && CD->isFunctionTemplateSpecialization()))
1852 Transform.transformConstructor(FTD, CD);
1855 AddedCopyOrMove |= CD->isCopyOrMoveConstructor();
1858 // Synthesize an X() -> X<...> guide if there were no declared constructors.
1859 // FIXME: The standard doesn't say (how) to do this.
1861 Transform.buildSimpleDeductionGuide(None);
1863 // Synthesize an X(X<...>) -> X<...> guide if there was no declared constructor
1864 // resembling a copy or move constructor.
1865 // FIXME: The standard doesn't say (how) to do this.
1866 if (!AddedCopyOrMove)
1867 Transform.buildSimpleDeductionGuide(Transform.DeducedType);
1870 /// \brief Diagnose the presence of a default template argument on a
1871 /// template parameter, which is ill-formed in certain contexts.
1873 /// \returns true if the default template argument should be dropped.
1874 static bool DiagnoseDefaultTemplateArgument(Sema &S,
1875 Sema::TemplateParamListContext TPC,
1876 SourceLocation ParamLoc,
1877 SourceRange DefArgRange) {
1879 case Sema::TPC_ClassTemplate:
1880 case Sema::TPC_VarTemplate:
1881 case Sema::TPC_TypeAliasTemplate:
1884 case Sema::TPC_FunctionTemplate:
1885 case Sema::TPC_FriendFunctionTemplateDefinition:
1886 // C++ [temp.param]p9:
1887 // A default template-argument shall not be specified in a
1888 // function template declaration or a function template
1890 // If a friend function template declaration specifies a default
1891 // template-argument, that declaration shall be a definition and shall be
1892 // the only declaration of the function template in the translation unit.
1893 // (C++98/03 doesn't have this wording; see DR226).
1894 S.Diag(ParamLoc, S.getLangOpts().CPlusPlus11 ?
1895 diag::warn_cxx98_compat_template_parameter_default_in_function_template
1896 : diag::ext_template_parameter_default_in_function_template)
1900 case Sema::TPC_ClassTemplateMember:
1901 // C++0x [temp.param]p9:
1902 // A default template-argument shall not be specified in the
1903 // template-parameter-lists of the definition of a member of a
1904 // class template that appears outside of the member's class.
1905 S.Diag(ParamLoc, diag::err_template_parameter_default_template_member)
1909 case Sema::TPC_FriendClassTemplate:
1910 case Sema::TPC_FriendFunctionTemplate:
1911 // C++ [temp.param]p9:
1912 // A default template-argument shall not be specified in a
1913 // friend template declaration.
1914 S.Diag(ParamLoc, diag::err_template_parameter_default_friend_template)
1918 // FIXME: C++0x [temp.param]p9 allows default template-arguments
1919 // for friend function templates if there is only a single
1920 // declaration (and it is a definition). Strange!
1923 llvm_unreachable("Invalid TemplateParamListContext!");
1926 /// \brief Check for unexpanded parameter packs within the template parameters
1927 /// of a template template parameter, recursively.
1928 static bool DiagnoseUnexpandedParameterPacks(Sema &S,
1929 TemplateTemplateParmDecl *TTP) {
1930 // A template template parameter which is a parameter pack is also a pack
1932 if (TTP->isParameterPack())
1935 TemplateParameterList *Params = TTP->getTemplateParameters();
1936 for (unsigned I = 0, N = Params->size(); I != N; ++I) {
1937 NamedDecl *P = Params->getParam(I);
1938 if (NonTypeTemplateParmDecl *NTTP = dyn_cast<NonTypeTemplateParmDecl>(P)) {
1939 if (!NTTP->isParameterPack() &&
1940 S.DiagnoseUnexpandedParameterPack(NTTP->getLocation(),
1941 NTTP->getTypeSourceInfo(),
1942 Sema::UPPC_NonTypeTemplateParameterType))
1948 if (TemplateTemplateParmDecl *InnerTTP
1949 = dyn_cast<TemplateTemplateParmDecl>(P))
1950 if (DiagnoseUnexpandedParameterPacks(S, InnerTTP))
1957 /// \brief Checks the validity of a template parameter list, possibly
1958 /// considering the template parameter list from a previous
1961 /// If an "old" template parameter list is provided, it must be
1962 /// equivalent (per TemplateParameterListsAreEqual) to the "new"
1963 /// template parameter list.
1965 /// \param NewParams Template parameter list for a new template
1966 /// declaration. This template parameter list will be updated with any
1967 /// default arguments that are carried through from the previous
1968 /// template parameter list.
1970 /// \param OldParams If provided, template parameter list from a
1971 /// previous declaration of the same template. Default template
1972 /// arguments will be merged from the old template parameter list to
1973 /// the new template parameter list.
1975 /// \param TPC Describes the context in which we are checking the given
1976 /// template parameter list.
1978 /// \returns true if an error occurred, false otherwise.
1979 bool Sema::CheckTemplateParameterList(TemplateParameterList *NewParams,
1980 TemplateParameterList *OldParams,
1981 TemplateParamListContext TPC) {
1982 bool Invalid = false;
1984 // C++ [temp.param]p10:
1985 // The set of default template-arguments available for use with a
1986 // template declaration or definition is obtained by merging the
1987 // default arguments from the definition (if in scope) and all
1988 // declarations in scope in the same way default function
1989 // arguments are (8.3.6).
1990 bool SawDefaultArgument = false;
1991 SourceLocation PreviousDefaultArgLoc;
1993 // Dummy initialization to avoid warnings.
1994 TemplateParameterList::iterator OldParam = NewParams->end();
1996 OldParam = OldParams->begin();
1998 bool RemoveDefaultArguments = false;
1999 for (TemplateParameterList::iterator NewParam = NewParams->begin(),
2000 NewParamEnd = NewParams->end();
2001 NewParam != NewParamEnd; ++NewParam) {
2002 // Variables used to diagnose redundant default arguments
2003 bool RedundantDefaultArg = false;
2004 SourceLocation OldDefaultLoc;
2005 SourceLocation NewDefaultLoc;
2007 // Variable used to diagnose missing default arguments
2008 bool MissingDefaultArg = false;
2010 // Variable used to diagnose non-final parameter packs
2011 bool SawParameterPack = false;
2013 if (TemplateTypeParmDecl *NewTypeParm
2014 = dyn_cast<TemplateTypeParmDecl>(*NewParam)) {
2015 // Check the presence of a default argument here.
2016 if (NewTypeParm->hasDefaultArgument() &&
2017 DiagnoseDefaultTemplateArgument(*this, TPC,
2018 NewTypeParm->getLocation(),
2019 NewTypeParm->getDefaultArgumentInfo()->getTypeLoc()
2021 NewTypeParm->removeDefaultArgument();
2023 // Merge default arguments for template type parameters.
2024 TemplateTypeParmDecl *OldTypeParm
2025 = OldParams? cast<TemplateTypeParmDecl>(*OldParam) : nullptr;
2026 if (NewTypeParm->isParameterPack()) {
2027 assert(!NewTypeParm->hasDefaultArgument() &&
2028 "Parameter packs can't have a default argument!");
2029 SawParameterPack = true;
2030 } else if (OldTypeParm && hasVisibleDefaultArgument(OldTypeParm) &&
2031 NewTypeParm->hasDefaultArgument()) {
2032 OldDefaultLoc = OldTypeParm->getDefaultArgumentLoc();
2033 NewDefaultLoc = NewTypeParm->getDefaultArgumentLoc();
2034 SawDefaultArgument = true;
2035 RedundantDefaultArg = true;
2036 PreviousDefaultArgLoc = NewDefaultLoc;
2037 } else if (OldTypeParm && OldTypeParm->hasDefaultArgument()) {
2038 // Merge the default argument from the old declaration to the
2040 NewTypeParm->setInheritedDefaultArgument(Context, OldTypeParm);
2041 PreviousDefaultArgLoc = OldTypeParm->getDefaultArgumentLoc();
2042 } else if (NewTypeParm->hasDefaultArgument()) {
2043 SawDefaultArgument = true;
2044 PreviousDefaultArgLoc = NewTypeParm->getDefaultArgumentLoc();
2045 } else if (SawDefaultArgument)
2046 MissingDefaultArg = true;
2047 } else if (NonTypeTemplateParmDecl *NewNonTypeParm
2048 = dyn_cast<NonTypeTemplateParmDecl>(*NewParam)) {
2049 // Check for unexpanded parameter packs.
2050 if (!NewNonTypeParm->isParameterPack() &&
2051 DiagnoseUnexpandedParameterPack(NewNonTypeParm->getLocation(),
2052 NewNonTypeParm->getTypeSourceInfo(),
2053 UPPC_NonTypeTemplateParameterType)) {
2058 // Check the presence of a default argument here.
2059 if (NewNonTypeParm->hasDefaultArgument() &&
2060 DiagnoseDefaultTemplateArgument(*this, TPC,
2061 NewNonTypeParm->getLocation(),
2062 NewNonTypeParm->getDefaultArgument()->getSourceRange())) {
2063 NewNonTypeParm->removeDefaultArgument();
2066 // Merge default arguments for non-type template parameters
2067 NonTypeTemplateParmDecl *OldNonTypeParm
2068 = OldParams? cast<NonTypeTemplateParmDecl>(*OldParam) : nullptr;
2069 if (NewNonTypeParm->isParameterPack()) {
2070 assert(!NewNonTypeParm->hasDefaultArgument() &&
2071 "Parameter packs can't have a default argument!");
2072 if (!NewNonTypeParm->isPackExpansion())
2073 SawParameterPack = true;
2074 } else if (OldNonTypeParm && hasVisibleDefaultArgument(OldNonTypeParm) &&
2075 NewNonTypeParm->hasDefaultArgument()) {
2076 OldDefaultLoc = OldNonTypeParm->getDefaultArgumentLoc();
2077 NewDefaultLoc = NewNonTypeParm->getDefaultArgumentLoc();
2078 SawDefaultArgument = true;
2079 RedundantDefaultArg = true;
2080 PreviousDefaultArgLoc = NewDefaultLoc;
2081 } else if (OldNonTypeParm && OldNonTypeParm->hasDefaultArgument()) {
2082 // Merge the default argument from the old declaration to the
2084 NewNonTypeParm->setInheritedDefaultArgument(Context, OldNonTypeParm);
2085 PreviousDefaultArgLoc = OldNonTypeParm->getDefaultArgumentLoc();
2086 } else if (NewNonTypeParm->hasDefaultArgument()) {
2087 SawDefaultArgument = true;
2088 PreviousDefaultArgLoc = NewNonTypeParm->getDefaultArgumentLoc();
2089 } else if (SawDefaultArgument)
2090 MissingDefaultArg = true;
2092 TemplateTemplateParmDecl *NewTemplateParm
2093 = cast<TemplateTemplateParmDecl>(*NewParam);
2095 // Check for unexpanded parameter packs, recursively.
2096 if (::DiagnoseUnexpandedParameterPacks(*this, NewTemplateParm)) {
2101 // Check the presence of a default argument here.
2102 if (NewTemplateParm->hasDefaultArgument() &&
2103 DiagnoseDefaultTemplateArgument(*this, TPC,
2104 NewTemplateParm->getLocation(),
2105 NewTemplateParm->getDefaultArgument().getSourceRange()))
2106 NewTemplateParm->removeDefaultArgument();
2108 // Merge default arguments for template template parameters
2109 TemplateTemplateParmDecl *OldTemplateParm
2110 = OldParams? cast<TemplateTemplateParmDecl>(*OldParam) : nullptr;
2111 if (NewTemplateParm->isParameterPack()) {
2112 assert(!NewTemplateParm->hasDefaultArgument() &&
2113 "Parameter packs can't have a default argument!");
2114 if (!NewTemplateParm->isPackExpansion())
2115 SawParameterPack = true;
2116 } else if (OldTemplateParm &&
2117 hasVisibleDefaultArgument(OldTemplateParm) &&
2118 NewTemplateParm->hasDefaultArgument()) {
2119 OldDefaultLoc = OldTemplateParm->getDefaultArgument().getLocation();
2120 NewDefaultLoc = NewTemplateParm->getDefaultArgument().getLocation();
2121 SawDefaultArgument = true;
2122 RedundantDefaultArg = true;
2123 PreviousDefaultArgLoc = NewDefaultLoc;
2124 } else if (OldTemplateParm && OldTemplateParm->hasDefaultArgument()) {
2125 // Merge the default argument from the old declaration to the
2127 NewTemplateParm->setInheritedDefaultArgument(Context, OldTemplateParm);
2128 PreviousDefaultArgLoc
2129 = OldTemplateParm->getDefaultArgument().getLocation();
2130 } else if (NewTemplateParm->hasDefaultArgument()) {
2131 SawDefaultArgument = true;
2132 PreviousDefaultArgLoc
2133 = NewTemplateParm->getDefaultArgument().getLocation();
2134 } else if (SawDefaultArgument)
2135 MissingDefaultArg = true;
2138 // C++11 [temp.param]p11:
2139 // If a template parameter of a primary class template or alias template
2140 // is a template parameter pack, it shall be the last template parameter.
2141 if (SawParameterPack && (NewParam + 1) != NewParamEnd &&
2142 (TPC == TPC_ClassTemplate || TPC == TPC_VarTemplate ||
2143 TPC == TPC_TypeAliasTemplate)) {
2144 Diag((*NewParam)->getLocation(),
2145 diag::err_template_param_pack_must_be_last_template_parameter);
2149 if (RedundantDefaultArg) {
2150 // C++ [temp.param]p12:
2151 // A template-parameter shall not be given default arguments
2152 // by two different declarations in the same scope.
2153 Diag(NewDefaultLoc, diag::err_template_param_default_arg_redefinition);
2154 Diag(OldDefaultLoc, diag::note_template_param_prev_default_arg);
2156 } else if (MissingDefaultArg && TPC != TPC_FunctionTemplate) {
2157 // C++ [temp.param]p11:
2158 // If a template-parameter of a class template has a default
2159 // template-argument, each subsequent template-parameter shall either
2160 // have a default template-argument supplied or be a template parameter
2162 Diag((*NewParam)->getLocation(),
2163 diag::err_template_param_default_arg_missing);
2164 Diag(PreviousDefaultArgLoc, diag::note_template_param_prev_default_arg);
2166 RemoveDefaultArguments = true;
2169 // If we have an old template parameter list that we're merging
2170 // in, move on to the next parameter.
2175 // We were missing some default arguments at the end of the list, so remove
2176 // all of the default arguments.
2177 if (RemoveDefaultArguments) {
2178 for (TemplateParameterList::iterator NewParam = NewParams->begin(),
2179 NewParamEnd = NewParams->end();
2180 NewParam != NewParamEnd; ++NewParam) {
2181 if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(*NewParam))
2182 TTP->removeDefaultArgument();
2183 else if (NonTypeTemplateParmDecl *NTTP
2184 = dyn_cast<NonTypeTemplateParmDecl>(*NewParam))
2185 NTTP->removeDefaultArgument();
2187 cast<TemplateTemplateParmDecl>(*NewParam)->removeDefaultArgument();
2196 /// A class which looks for a use of a certain level of template
2198 struct DependencyChecker : RecursiveASTVisitor<DependencyChecker> {
2199 typedef RecursiveASTVisitor<DependencyChecker> super;
2203 // Whether we're looking for a use of a template parameter that makes the
2204 // overall construct type-dependent / a dependent type. This is strictly
2205 // best-effort for now; we may fail to match at all for a dependent type
2206 // in some cases if this is set.
2207 bool IgnoreNonTypeDependent;
2210 SourceLocation MatchLoc;
2212 DependencyChecker(unsigned Depth, bool IgnoreNonTypeDependent)
2213 : Depth(Depth), IgnoreNonTypeDependent(IgnoreNonTypeDependent),
2216 DependencyChecker(TemplateParameterList *Params, bool IgnoreNonTypeDependent)
2217 : IgnoreNonTypeDependent(IgnoreNonTypeDependent), Match(false) {
2218 NamedDecl *ND = Params->getParam(0);
2219 if (TemplateTypeParmDecl *PD = dyn_cast<TemplateTypeParmDecl>(ND)) {
2220 Depth = PD->getDepth();
2221 } else if (NonTypeTemplateParmDecl *PD =
2222 dyn_cast<NonTypeTemplateParmDecl>(ND)) {
2223 Depth = PD->getDepth();
2225 Depth = cast<TemplateTemplateParmDecl>(ND)->getDepth();
2229 bool Matches(unsigned ParmDepth, SourceLocation Loc = SourceLocation()) {
2230 if (ParmDepth >= Depth) {
2238 bool TraverseStmt(Stmt *S, DataRecursionQueue *Q = nullptr) {
2239 // Prune out non-type-dependent expressions if requested. This can
2240 // sometimes result in us failing to find a template parameter reference
2241 // (if a value-dependent expression creates a dependent type), but this
2242 // mode is best-effort only.
2243 if (auto *E = dyn_cast_or_null<Expr>(S))
2244 if (IgnoreNonTypeDependent && !E->isTypeDependent())
2246 return super::TraverseStmt(S, Q);
2249 bool TraverseTypeLoc(TypeLoc TL) {
2250 if (IgnoreNonTypeDependent && !TL.isNull() &&
2251 !TL.getType()->isDependentType())
2253 return super::TraverseTypeLoc(TL);
2256 bool VisitTemplateTypeParmTypeLoc(TemplateTypeParmTypeLoc TL) {
2257 return !Matches(TL.getTypePtr()->getDepth(), TL.getNameLoc());
2260 bool VisitTemplateTypeParmType(const TemplateTypeParmType *T) {
2261 // For a best-effort search, keep looking until we find a location.
2262 return IgnoreNonTypeDependent || !Matches(T->getDepth());
2265 bool TraverseTemplateName(TemplateName N) {
2266 if (TemplateTemplateParmDecl *PD =
2267 dyn_cast_or_null<TemplateTemplateParmDecl>(N.getAsTemplateDecl()))
2268 if (Matches(PD->getDepth()))
2270 return super::TraverseTemplateName(N);
2273 bool VisitDeclRefExpr(DeclRefExpr *E) {
2274 if (NonTypeTemplateParmDecl *PD =
2275 dyn_cast<NonTypeTemplateParmDecl>(E->getDecl()))
2276 if (Matches(PD->getDepth(), E->getExprLoc()))
2278 return super::VisitDeclRefExpr(E);
2281 bool VisitSubstTemplateTypeParmType(const SubstTemplateTypeParmType *T) {
2282 return TraverseType(T->getReplacementType());
2286 VisitSubstTemplateTypeParmPackType(const SubstTemplateTypeParmPackType *T) {
2287 return TraverseTemplateArgument(T->getArgumentPack());
2290 bool TraverseInjectedClassNameType(const InjectedClassNameType *T) {
2291 return TraverseType(T->getInjectedSpecializationType());
2294 } // end anonymous namespace
2296 /// Determines whether a given type depends on the given parameter
2299 DependsOnTemplateParameters(QualType T, TemplateParameterList *Params) {
2300 DependencyChecker Checker(Params, /*IgnoreNonTypeDependent*/false);
2301 Checker.TraverseType(T);
2302 return Checker.Match;
2305 // Find the source range corresponding to the named type in the given
2306 // nested-name-specifier, if any.
2307 static SourceRange getRangeOfTypeInNestedNameSpecifier(ASTContext &Context,
2309 const CXXScopeSpec &SS) {
2310 NestedNameSpecifierLoc NNSLoc(SS.getScopeRep(), SS.location_data());
2311 while (NestedNameSpecifier *NNS = NNSLoc.getNestedNameSpecifier()) {
2312 if (const Type *CurType = NNS->getAsType()) {
2313 if (Context.hasSameUnqualifiedType(T, QualType(CurType, 0)))
2314 return NNSLoc.getTypeLoc().getSourceRange();
2318 NNSLoc = NNSLoc.getPrefix();
2321 return SourceRange();
2324 /// \brief Match the given template parameter lists to the given scope
2325 /// specifier, returning the template parameter list that applies to the
2328 /// \param DeclStartLoc the start of the declaration that has a scope
2329 /// specifier or a template parameter list.
2331 /// \param DeclLoc The location of the declaration itself.
2333 /// \param SS the scope specifier that will be matched to the given template
2334 /// parameter lists. This scope specifier precedes a qualified name that is
2337 /// \param TemplateId The template-id following the scope specifier, if there
2338 /// is one. Used to check for a missing 'template<>'.
2340 /// \param ParamLists the template parameter lists, from the outermost to the
2341 /// innermost template parameter lists.
2343 /// \param IsFriend Whether to apply the slightly different rules for
2344 /// matching template parameters to scope specifiers in friend
2347 /// \param IsMemberSpecialization will be set true if the scope specifier
2348 /// denotes a fully-specialized type, and therefore this is a declaration of
2349 /// a member specialization.
2351 /// \returns the template parameter list, if any, that corresponds to the
2352 /// name that is preceded by the scope specifier @p SS. This template
2353 /// parameter list may have template parameters (if we're declaring a
2354 /// template) or may have no template parameters (if we're declaring a
2355 /// template specialization), or may be NULL (if what we're declaring isn't
2356 /// itself a template).
2357 TemplateParameterList *Sema::MatchTemplateParametersToScopeSpecifier(
2358 SourceLocation DeclStartLoc, SourceLocation DeclLoc, const CXXScopeSpec &SS,
2359 TemplateIdAnnotation *TemplateId,
2360 ArrayRef<TemplateParameterList *> ParamLists, bool IsFriend,
2361 bool &IsMemberSpecialization, bool &Invalid) {
2362 IsMemberSpecialization = false;
2365 // The sequence of nested types to which we will match up the template
2366 // parameter lists. We first build this list by starting with the type named
2367 // by the nested-name-specifier and walking out until we run out of types.
2368 SmallVector<QualType, 4> NestedTypes;
2370 if (SS.getScopeRep()) {
2371 if (CXXRecordDecl *Record
2372 = dyn_cast_or_null<CXXRecordDecl>(computeDeclContext(SS, true)))
2373 T = Context.getTypeDeclType(Record);
2375 T = QualType(SS.getScopeRep()->getAsType(), 0);
2378 // If we found an explicit specialization that prevents us from needing
2379 // 'template<>' headers, this will be set to the location of that
2380 // explicit specialization.
2381 SourceLocation ExplicitSpecLoc;
2383 while (!T.isNull()) {
2384 NestedTypes.push_back(T);
2386 // Retrieve the parent of a record type.
2387 if (CXXRecordDecl *Record = T->getAsCXXRecordDecl()) {
2388 // If this type is an explicit specialization, we're done.
2389 if (ClassTemplateSpecializationDecl *Spec
2390 = dyn_cast<ClassTemplateSpecializationDecl>(Record)) {
2391 if (!isa<ClassTemplatePartialSpecializationDecl>(Spec) &&
2392 Spec->getSpecializationKind() == TSK_ExplicitSpecialization) {
2393 ExplicitSpecLoc = Spec->getLocation();
2396 } else if (Record->getTemplateSpecializationKind()
2397 == TSK_ExplicitSpecialization) {
2398 ExplicitSpecLoc = Record->getLocation();
2402 if (TypeDecl *Parent = dyn_cast<TypeDecl>(Record->getParent()))
2403 T = Context.getTypeDeclType(Parent);
2409 if (const TemplateSpecializationType *TST
2410 = T->getAs<TemplateSpecializationType>()) {
2411 if (TemplateDecl *Template = TST->getTemplateName().getAsTemplateDecl()) {
2412 if (TypeDecl *Parent = dyn_cast<TypeDecl>(Template->getDeclContext()))
2413 T = Context.getTypeDeclType(Parent);
2420 // Look one step prior in a dependent template specialization type.
2421 if (const DependentTemplateSpecializationType *DependentTST
2422 = T->getAs<DependentTemplateSpecializationType>()) {
2423 if (NestedNameSpecifier *NNS = DependentTST->getQualifier())
2424 T = QualType(NNS->getAsType(), 0);
2430 // Look one step prior in a dependent name type.
2431 if (const DependentNameType *DependentName = T->getAs<DependentNameType>()){
2432 if (NestedNameSpecifier *NNS = DependentName->getQualifier())
2433 T = QualType(NNS->getAsType(), 0);
2439 // Retrieve the parent of an enumeration type.
2440 if (const EnumType *EnumT = T->getAs<EnumType>()) {
2441 // FIXME: Forward-declared enums require a TSK_ExplicitSpecialization
2443 EnumDecl *Enum = EnumT->getDecl();
2445 // Get to the parent type.
2446 if (TypeDecl *Parent = dyn_cast<TypeDecl>(Enum->getParent()))
2447 T = Context.getTypeDeclType(Parent);
2455 // Reverse the nested types list, since we want to traverse from the outermost
2456 // to the innermost while checking template-parameter-lists.
2457 std::reverse(NestedTypes.begin(), NestedTypes.end());
2459 // C++0x [temp.expl.spec]p17:
2460 // A member or a member template may be nested within many
2461 // enclosing class templates. In an explicit specialization for
2462 // such a member, the member declaration shall be preceded by a
2463 // template<> for each enclosing class template that is
2464 // explicitly specialized.
2465 bool SawNonEmptyTemplateParameterList = false;
2467 auto CheckExplicitSpecialization = [&](SourceRange Range, bool Recovery) {
2468 if (SawNonEmptyTemplateParameterList) {
2469 Diag(DeclLoc, diag::err_specialize_member_of_template)
2470 << !Recovery << Range;
2472 IsMemberSpecialization = false;
2479 auto DiagnoseMissingExplicitSpecialization = [&] (SourceRange Range) {
2480 // Check that we can have an explicit specialization here.
2481 if (CheckExplicitSpecialization(Range, true))
2484 // We don't have a template header, but we should.
2485 SourceLocation ExpectedTemplateLoc;
2486 if (!ParamLists.empty())
2487 ExpectedTemplateLoc = ParamLists[0]->getTemplateLoc();
2489 ExpectedTemplateLoc = DeclStartLoc;
2491 Diag(DeclLoc, diag::err_template_spec_needs_header)
2493 << FixItHint::CreateInsertion(ExpectedTemplateLoc, "template<> ");
2497 unsigned ParamIdx = 0;
2498 for (unsigned TypeIdx = 0, NumTypes = NestedTypes.size(); TypeIdx != NumTypes;
2500 T = NestedTypes[TypeIdx];
2502 // Whether we expect a 'template<>' header.
2503 bool NeedEmptyTemplateHeader = false;
2505 // Whether we expect a template header with parameters.
2506 bool NeedNonemptyTemplateHeader = false;
2508 // For a dependent type, the set of template parameters that we
2510 TemplateParameterList *ExpectedTemplateParams = nullptr;
2512 // C++0x [temp.expl.spec]p15:
2513 // A member or a member template may be nested within many enclosing
2514 // class templates. In an explicit specialization for such a member, the
2515 // member declaration shall be preceded by a template<> for each
2516 // enclosing class template that is explicitly specialized.
2517 if (CXXRecordDecl *Record = T->getAsCXXRecordDecl()) {
2518 if (ClassTemplatePartialSpecializationDecl *Partial
2519 = dyn_cast<ClassTemplatePartialSpecializationDecl>(Record)) {
2520 ExpectedTemplateParams = Partial->getTemplateParameters();
2521 NeedNonemptyTemplateHeader = true;
2522 } else if (Record->isDependentType()) {
2523 if (Record->getDescribedClassTemplate()) {
2524 ExpectedTemplateParams = Record->getDescribedClassTemplate()
2525 ->getTemplateParameters();
2526 NeedNonemptyTemplateHeader = true;
2528 } else if (ClassTemplateSpecializationDecl *Spec
2529 = dyn_cast<ClassTemplateSpecializationDecl>(Record)) {
2530 // C++0x [temp.expl.spec]p4:
2531 // Members of an explicitly specialized class template are defined
2532 // in the same manner as members of normal classes, and not using
2533 // the template<> syntax.
2534 if (Spec->getSpecializationKind() != TSK_ExplicitSpecialization)
2535 NeedEmptyTemplateHeader = true;
2538 } else if (Record->getTemplateSpecializationKind()) {
2539 if (Record->getTemplateSpecializationKind()
2540 != TSK_ExplicitSpecialization &&
2541 TypeIdx == NumTypes - 1)
2542 IsMemberSpecialization = true;
2546 } else if (const TemplateSpecializationType *TST
2547 = T->getAs<TemplateSpecializationType>()) {
2548 if (TemplateDecl *Template = TST->getTemplateName().getAsTemplateDecl()) {
2549 ExpectedTemplateParams = Template->getTemplateParameters();
2550 NeedNonemptyTemplateHeader = true;
2552 } else if (T->getAs<DependentTemplateSpecializationType>()) {
2553 // FIXME: We actually could/should check the template arguments here
2554 // against the corresponding template parameter list.
2555 NeedNonemptyTemplateHeader = false;
2558 // C++ [temp.expl.spec]p16:
2559 // In an explicit specialization declaration for a member of a class
2560 // template or a member template that ap- pears in namespace scope, the
2561 // member template and some of its enclosing class templates may remain
2562 // unspecialized, except that the declaration shall not explicitly
2563 // specialize a class member template if its en- closing class templates
2564 // are not explicitly specialized as well.
2565 if (ParamIdx < ParamLists.size()) {
2566 if (ParamLists[ParamIdx]->size() == 0) {
2567 if (CheckExplicitSpecialization(ParamLists[ParamIdx]->getSourceRange(),
2571 SawNonEmptyTemplateParameterList = true;
2574 if (NeedEmptyTemplateHeader) {
2575 // If we're on the last of the types, and we need a 'template<>' header
2576 // here, then it's a member specialization.
2577 if (TypeIdx == NumTypes - 1)
2578 IsMemberSpecialization = true;
2580 if (ParamIdx < ParamLists.size()) {
2581 if (ParamLists[ParamIdx]->size() > 0) {
2582 // The header has template parameters when it shouldn't. Complain.
2583 Diag(ParamLists[ParamIdx]->getTemplateLoc(),
2584 diag::err_template_param_list_matches_nontemplate)
2586 << SourceRange(ParamLists[ParamIdx]->getLAngleLoc(),
2587 ParamLists[ParamIdx]->getRAngleLoc())
2588 << getRangeOfTypeInNestedNameSpecifier(Context, T, SS);
2593 // Consume this template header.
2599 if (DiagnoseMissingExplicitSpecialization(
2600 getRangeOfTypeInNestedNameSpecifier(Context, T, SS)))
2606 if (NeedNonemptyTemplateHeader) {
2607 // In friend declarations we can have template-ids which don't
2608 // depend on the corresponding template parameter lists. But
2609 // assume that empty parameter lists are supposed to match this
2611 if (IsFriend && T->isDependentType()) {
2612 if (ParamIdx < ParamLists.size() &&
2613 DependsOnTemplateParameters(T, ParamLists[ParamIdx]))
2614 ExpectedTemplateParams = nullptr;
2619 if (ParamIdx < ParamLists.size()) {
2620 // Check the template parameter list, if we can.
2621 if (ExpectedTemplateParams &&
2622 !TemplateParameterListsAreEqual(ParamLists[ParamIdx],
2623 ExpectedTemplateParams,
2624 true, TPL_TemplateMatch))
2628 CheckTemplateParameterList(ParamLists[ParamIdx], nullptr,
2629 TPC_ClassTemplateMember))
2636 Diag(DeclLoc, diag::err_template_spec_needs_template_parameters)
2638 << getRangeOfTypeInNestedNameSpecifier(Context, T, SS);
2644 // If there were at least as many template-ids as there were template
2645 // parameter lists, then there are no template parameter lists remaining for
2646 // the declaration itself.
2647 if (ParamIdx >= ParamLists.size()) {
2648 if (TemplateId && !IsFriend) {
2649 // We don't have a template header for the declaration itself, but we
2651 DiagnoseMissingExplicitSpecialization(SourceRange(TemplateId->LAngleLoc,
2652 TemplateId->RAngleLoc));
2654 // Fabricate an empty template parameter list for the invented header.
2655 return TemplateParameterList::Create(Context, SourceLocation(),
2656 SourceLocation(), None,
2657 SourceLocation(), nullptr);
2663 // If there were too many template parameter lists, complain about that now.
2664 if (ParamIdx < ParamLists.size() - 1) {
2665 bool HasAnyExplicitSpecHeader = false;
2666 bool AllExplicitSpecHeaders = true;
2667 for (unsigned I = ParamIdx, E = ParamLists.size() - 1; I != E; ++I) {
2668 if (ParamLists[I]->size() == 0)
2669 HasAnyExplicitSpecHeader = true;
2671 AllExplicitSpecHeaders = false;
2674 Diag(ParamLists[ParamIdx]->getTemplateLoc(),
2675 AllExplicitSpecHeaders ? diag::warn_template_spec_extra_headers
2676 : diag::err_template_spec_extra_headers)
2677 << SourceRange(ParamLists[ParamIdx]->getTemplateLoc(),
2678 ParamLists[ParamLists.size() - 2]->getRAngleLoc());
2680 // If there was a specialization somewhere, such that 'template<>' is
2681 // not required, and there were any 'template<>' headers, note where the
2682 // specialization occurred.
2683 if (ExplicitSpecLoc.isValid() && HasAnyExplicitSpecHeader)
2684 Diag(ExplicitSpecLoc,
2685 diag::note_explicit_template_spec_does_not_need_header)
2686 << NestedTypes.back();
2688 // We have a template parameter list with no corresponding scope, which
2689 // means that the resulting template declaration can't be instantiated
2690 // properly (we'll end up with dependent nodes when we shouldn't).
2691 if (!AllExplicitSpecHeaders)
2695 // C++ [temp.expl.spec]p16:
2696 // In an explicit specialization declaration for a member of a class
2697 // template or a member template that ap- pears in namespace scope, the
2698 // member template and some of its enclosing class templates may remain
2699 // unspecialized, except that the declaration shall not explicitly
2700 // specialize a class member template if its en- closing class templates
2701 // are not explicitly specialized as well.
2702 if (ParamLists.back()->size() == 0 &&
2703 CheckExplicitSpecialization(ParamLists[ParamIdx]->getSourceRange(),
2707 // Return the last template parameter list, which corresponds to the
2708 // entity being declared.
2709 return ParamLists.back();
2712 void Sema::NoteAllFoundTemplates(TemplateName Name) {
2713 if (TemplateDecl *Template = Name.getAsTemplateDecl()) {
2714 Diag(Template->getLocation(), diag::note_template_declared_here)
2715 << (isa<FunctionTemplateDecl>(Template)
2717 : isa<ClassTemplateDecl>(Template)
2719 : isa<VarTemplateDecl>(Template)
2721 : isa<TypeAliasTemplateDecl>(Template) ? 3 : 4)
2722 << Template->getDeclName();
2726 if (OverloadedTemplateStorage *OST = Name.getAsOverloadedTemplate()) {
2727 for (OverloadedTemplateStorage::iterator I = OST->begin(),
2730 Diag((*I)->getLocation(), diag::note_template_declared_here)
2731 << 0 << (*I)->getDeclName();
2738 checkBuiltinTemplateIdType(Sema &SemaRef, BuiltinTemplateDecl *BTD,
2739 const SmallVectorImpl<TemplateArgument> &Converted,
2740 SourceLocation TemplateLoc,
2741 TemplateArgumentListInfo &TemplateArgs) {
2742 ASTContext &Context = SemaRef.getASTContext();
2743 switch (BTD->getBuiltinTemplateKind()) {
2744 case BTK__make_integer_seq: {
2745 // Specializations of __make_integer_seq<S, T, N> are treated like
2746 // S<T, 0, ..., N-1>.
2748 // C++14 [inteseq.intseq]p1:
2749 // T shall be an integer type.
2750 if (!Converted[1].getAsType()->isIntegralType(Context)) {
2751 SemaRef.Diag(TemplateArgs[1].getLocation(),
2752 diag::err_integer_sequence_integral_element_type);
2756 // C++14 [inteseq.make]p1:
2757 // If N is negative the program is ill-formed.
2758 TemplateArgument NumArgsArg = Converted[2];
2759 llvm::APSInt NumArgs = NumArgsArg.getAsIntegral();
2761 SemaRef.Diag(TemplateArgs[2].getLocation(),
2762 diag::err_integer_sequence_negative_length);
2766 QualType ArgTy = NumArgsArg.getIntegralType();
2767 TemplateArgumentListInfo SyntheticTemplateArgs;
2768 // The type argument gets reused as the first template argument in the
2769 // synthetic template argument list.
2770 SyntheticTemplateArgs.addArgument(TemplateArgs[1]);
2771 // Expand N into 0 ... N-1.
2772 for (llvm::APSInt I(NumArgs.getBitWidth(), NumArgs.isUnsigned());
2774 TemplateArgument TA(Context, I, ArgTy);
2775 SyntheticTemplateArgs.addArgument(SemaRef.getTrivialTemplateArgumentLoc(
2776 TA, ArgTy, TemplateArgs[2].getLocation()));
2778 // The first template argument will be reused as the template decl that
2779 // our synthetic template arguments will be applied to.
2780 return SemaRef.CheckTemplateIdType(Converted[0].getAsTemplate(),
2781 TemplateLoc, SyntheticTemplateArgs);
2784 case BTK__type_pack_element:
2785 // Specializations of
2786 // __type_pack_element<Index, T_1, ..., T_N>
2787 // are treated like T_Index.
2788 assert(Converted.size() == 2 &&
2789 "__type_pack_element should be given an index and a parameter pack");
2791 // If the Index is out of bounds, the program is ill-formed.
2792 TemplateArgument IndexArg = Converted[0], Ts = Converted[1];
2793 llvm::APSInt Index = IndexArg.getAsIntegral();
2794 assert(Index >= 0 && "the index used with __type_pack_element should be of "
2795 "type std::size_t, and hence be non-negative");
2796 if (Index >= Ts.pack_size()) {
2797 SemaRef.Diag(TemplateArgs[0].getLocation(),
2798 diag::err_type_pack_element_out_of_bounds);
2802 // We simply return the type at index `Index`.
2803 auto Nth = std::next(Ts.pack_begin(), Index.getExtValue());
2804 return Nth->getAsType();
2806 llvm_unreachable("unexpected BuiltinTemplateDecl!");
2809 QualType Sema::CheckTemplateIdType(TemplateName Name,
2810 SourceLocation TemplateLoc,
2811 TemplateArgumentListInfo &TemplateArgs) {
2812 DependentTemplateName *DTN
2813 = Name.getUnderlying().getAsDependentTemplateName();
2814 if (DTN && DTN->isIdentifier())
2815 // When building a template-id where the template-name is dependent,
2816 // assume the template is a type template. Either our assumption is
2817 // correct, or the code is ill-formed and will be diagnosed when the
2818 // dependent name is substituted.
2819 return Context.getDependentTemplateSpecializationType(ETK_None,
2820 DTN->getQualifier(),
2821 DTN->getIdentifier(),
2824 TemplateDecl *Template = Name.getAsTemplateDecl();
2825 if (!Template || isa<FunctionTemplateDecl>(Template) ||
2826 isa<VarTemplateDecl>(Template)) {
2827 // We might have a substituted template template parameter pack. If so,
2828 // build a template specialization type for it.
2829 if (Name.getAsSubstTemplateTemplateParmPack())
2830 return Context.getTemplateSpecializationType(Name, TemplateArgs);
2832 Diag(TemplateLoc, diag::err_template_id_not_a_type)
2834 NoteAllFoundTemplates(Name);
2838 // Check that the template argument list is well-formed for this
2840 SmallVector<TemplateArgument, 4> Converted;
2841 if (CheckTemplateArgumentList(Template, TemplateLoc, TemplateArgs,
2847 bool InstantiationDependent = false;
2848 if (TypeAliasTemplateDecl *AliasTemplate =
2849 dyn_cast<TypeAliasTemplateDecl>(Template)) {
2850 // Find the canonical type for this type alias template specialization.
2851 TypeAliasDecl *Pattern = AliasTemplate->getTemplatedDecl();
2852 if (Pattern->isInvalidDecl())
2855 TemplateArgumentList TemplateArgs(TemplateArgumentList::OnStack,
2858 // Only substitute for the innermost template argument list.
2859 MultiLevelTemplateArgumentList TemplateArgLists;
2860 TemplateArgLists.addOuterTemplateArguments(&TemplateArgs);
2861 unsigned Depth = AliasTemplate->getTemplateParameters()->getDepth();
2862 for (unsigned I = 0; I < Depth; ++I)
2863 TemplateArgLists.addOuterTemplateArguments(None);
2865 LocalInstantiationScope Scope(*this);
2866 InstantiatingTemplate Inst(*this, TemplateLoc, Template);
2867 if (Inst.isInvalid())
2870 CanonType = SubstType(Pattern->getUnderlyingType(),
2871 TemplateArgLists, AliasTemplate->getLocation(),
2872 AliasTemplate->getDeclName());
2873 if (CanonType.isNull())
2875 } else if (Name.isDependent() ||
2876 TemplateSpecializationType::anyDependentTemplateArguments(
2877 TemplateArgs, InstantiationDependent)) {
2878 // This class template specialization is a dependent
2879 // type. Therefore, its canonical type is another class template
2880 // specialization type that contains all of the converted
2881 // arguments in canonical form. This ensures that, e.g., A<T> and
2882 // A<T, T> have identical types when A is declared as:
2884 // template<typename T, typename U = T> struct A;
2885 CanonType = Context.getCanonicalTemplateSpecializationType(Name, Converted);
2887 // This might work out to be a current instantiation, in which
2888 // case the canonical type needs to be the InjectedClassNameType.
2890 // TODO: in theory this could be a simple hashtable lookup; most
2891 // changes to CurContext don't change the set of current
2893 if (isa<ClassTemplateDecl>(Template)) {
2894 for (DeclContext *Ctx = CurContext; Ctx; Ctx = Ctx->getLookupParent()) {
2895 // If we get out to a namespace, we're done.
2896 if (Ctx->isFileContext()) break;
2898 // If this isn't a record, keep looking.
2899 CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(Ctx);
2900 if (!Record) continue;
2902 // Look for one of the two cases with InjectedClassNameTypes
2903 // and check whether it's the same template.
2904 if (!isa<ClassTemplatePartialSpecializationDecl>(Record) &&
2905 !Record->getDescribedClassTemplate())
2908 // Fetch the injected class name type and check whether its
2909 // injected type is equal to the type we just built.
2910 QualType ICNT = Context.getTypeDeclType(Record);
2911 QualType Injected = cast<InjectedClassNameType>(ICNT)
2912 ->getInjectedSpecializationType();
2914 if (CanonType != Injected->getCanonicalTypeInternal())
2917 // If so, the canonical type of this TST is the injected
2918 // class name type of the record we just found.
2919 assert(ICNT.isCanonical());
2924 } else if (ClassTemplateDecl *ClassTemplate
2925 = dyn_cast<ClassTemplateDecl>(Template)) {
2926 // Find the class template specialization declaration that
2927 // corresponds to these arguments.
2928 void *InsertPos = nullptr;
2929 ClassTemplateSpecializationDecl *Decl
2930 = ClassTemplate->findSpecialization(Converted, InsertPos);
2932 // This is the first time we have referenced this class template
2933 // specialization. Create the canonical declaration and add it to
2934 // the set of specializations.
2935 Decl = ClassTemplateSpecializationDecl::Create(Context,
2936 ClassTemplate->getTemplatedDecl()->getTagKind(),
2937 ClassTemplate->getDeclContext(),
2938 ClassTemplate->getTemplatedDecl()->getLocStart(),
2939 ClassTemplate->getLocation(),
2941 Converted, nullptr);
2942 ClassTemplate->AddSpecialization(Decl, InsertPos);
2943 if (ClassTemplate->isOutOfLine())
2944 Decl->setLexicalDeclContext(ClassTemplate->getLexicalDeclContext());
2947 if (Decl->getSpecializationKind() == TSK_Undeclared) {
2948 MultiLevelTemplateArgumentList TemplateArgLists;
2949 TemplateArgLists.addOuterTemplateArguments(Converted);
2950 InstantiateAttrsForDecl(TemplateArgLists, ClassTemplate->getTemplatedDecl(),
2954 // Diagnose uses of this specialization.
2955 (void)DiagnoseUseOfDecl(Decl, TemplateLoc);
2957 CanonType = Context.getTypeDeclType(Decl);
2958 assert(isa<RecordType>(CanonType) &&
2959 "type of non-dependent specialization is not a RecordType");
2960 } else if (auto *BTD = dyn_cast<BuiltinTemplateDecl>(Template)) {
2961 CanonType = checkBuiltinTemplateIdType(*this, BTD, Converted, TemplateLoc,
2965 // Build the fully-sugared type for this class template
2966 // specialization, which refers back to the class template
2967 // specialization we created or found.
2968 return Context.getTemplateSpecializationType(Name, TemplateArgs, CanonType);
2972 Sema::ActOnTemplateIdType(CXXScopeSpec &SS, SourceLocation TemplateKWLoc,
2973 TemplateTy TemplateD, IdentifierInfo *TemplateII,
2974 SourceLocation TemplateIILoc,
2975 SourceLocation LAngleLoc,
2976 ASTTemplateArgsPtr TemplateArgsIn,
2977 SourceLocation RAngleLoc,
2978 bool IsCtorOrDtorName, bool IsClassName) {
2982 if (!IsCtorOrDtorName && !IsClassName && SS.isSet()) {
2983 DeclContext *LookupCtx = computeDeclContext(SS, /*EnteringContext*/false);
2985 // C++ [temp.res]p3:
2986 // A qualified-id that refers to a type and in which the
2987 // nested-name-specifier depends on a template-parameter (14.6.2)
2988 // shall be prefixed by the keyword typename to indicate that the
2989 // qualified-id denotes a type, forming an
2990 // elaborated-type-specifier (7.1.5.3).
2991 if (!LookupCtx && isDependentScopeSpecifier(SS)) {
2992 Diag(SS.getBeginLoc(), diag::err_typename_missing_template)
2993 << SS.getScopeRep() << TemplateII->getName();
2994 // Recover as if 'typename' were specified.
2995 // FIXME: This is not quite correct recovery as we don't transform SS
2996 // into the corresponding dependent form (and we don't diagnose missing
2997 // 'template' keywords within SS as a result).
2998 return ActOnTypenameType(nullptr, SourceLocation(), SS, TemplateKWLoc,
2999 TemplateD, TemplateII, TemplateIILoc, LAngleLoc,
3000 TemplateArgsIn, RAngleLoc);
3003 // Per C++ [class.qual]p2, if the template-id was an injected-class-name,
3004 // it's not actually allowed to be used as a type in most cases. Because
3005 // we annotate it before we know whether it's valid, we have to check for
3007 auto *LookupRD = dyn_cast_or_null<CXXRecordDecl>(LookupCtx);
3008 if (LookupRD && LookupRD->getIdentifier() == TemplateII) {
3010 TemplateKWLoc.isInvalid()
3011 ? diag::err_out_of_line_qualified_id_type_names_constructor
3012 : diag::ext_out_of_line_qualified_id_type_names_constructor)
3013 << TemplateII << 0 /*injected-class-name used as template name*/
3014 << 1 /*if any keyword was present, it was 'template'*/;
3018 TemplateName Template = TemplateD.get();
3020 // Translate the parser's template argument list in our AST format.
3021 TemplateArgumentListInfo TemplateArgs(LAngleLoc, RAngleLoc);
3022 translateTemplateArguments(TemplateArgsIn, TemplateArgs);
3024 if (DependentTemplateName *DTN = Template.getAsDependentTemplateName()) {
3026 = Context.getDependentTemplateSpecializationType(ETK_None,
3027 DTN->getQualifier(),
3028 DTN->getIdentifier(),
3030 // Build type-source information.
3032 DependentTemplateSpecializationTypeLoc SpecTL
3033 = TLB.push<DependentTemplateSpecializationTypeLoc>(T);
3034 SpecTL.setElaboratedKeywordLoc(SourceLocation());
3035 SpecTL.setQualifierLoc(SS.getWithLocInContext(Context));
3036 SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
3037 SpecTL.setTemplateNameLoc(TemplateIILoc);
3038 SpecTL.setLAngleLoc(LAngleLoc);
3039 SpecTL.setRAngleLoc(RAngleLoc);
3040 for (unsigned I = 0, N = SpecTL.getNumArgs(); I != N; ++I)
3041 SpecTL.setArgLocInfo(I, TemplateArgs[I].getLocInfo());
3042 return CreateParsedType(T, TLB.getTypeSourceInfo(Context, T));
3045 QualType Result = CheckTemplateIdType(Template, TemplateIILoc, TemplateArgs);
3046 if (Result.isNull())
3049 // Build type-source information.
3051 TemplateSpecializationTypeLoc SpecTL
3052 = TLB.push<TemplateSpecializationTypeLoc>(Result);
3053 SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
3054 SpecTL.setTemplateNameLoc(TemplateIILoc);
3055 SpecTL.setLAngleLoc(LAngleLoc);
3056 SpecTL.setRAngleLoc(RAngleLoc);
3057 for (unsigned i = 0, e = SpecTL.getNumArgs(); i != e; ++i)
3058 SpecTL.setArgLocInfo(i, TemplateArgs[i].getLocInfo());
3060 // NOTE: avoid constructing an ElaboratedTypeLoc if this is a
3061 // constructor or destructor name (in such a case, the scope specifier
3062 // will be attached to the enclosing Decl or Expr node).
3063 if (SS.isNotEmpty() && !IsCtorOrDtorName) {
3064 // Create an elaborated-type-specifier containing the nested-name-specifier.
3065 Result = Context.getElaboratedType(ETK_None, SS.getScopeRep(), Result);
3066 ElaboratedTypeLoc ElabTL = TLB.push<ElaboratedTypeLoc>(Result);
3067 ElabTL.setElaboratedKeywordLoc(SourceLocation());
3068 ElabTL.setQualifierLoc(SS.getWithLocInContext(Context));
3071 return CreateParsedType(Result, TLB.getTypeSourceInfo(Context, Result));
3074 TypeResult Sema::ActOnTagTemplateIdType(TagUseKind TUK,
3075 TypeSpecifierType TagSpec,
3076 SourceLocation TagLoc,
3078 SourceLocation TemplateKWLoc,
3079 TemplateTy TemplateD,
3080 SourceLocation TemplateLoc,
3081 SourceLocation LAngleLoc,
3082 ASTTemplateArgsPtr TemplateArgsIn,
3083 SourceLocation RAngleLoc) {
3084 TemplateName Template = TemplateD.get();
3086 // Translate the parser's template argument list in our AST format.
3087 TemplateArgumentListInfo TemplateArgs(LAngleLoc, RAngleLoc);
3088 translateTemplateArguments(TemplateArgsIn, TemplateArgs);
3090 // Determine the tag kind
3091 TagTypeKind TagKind = TypeWithKeyword::getTagTypeKindForTypeSpec(TagSpec);
3092 ElaboratedTypeKeyword Keyword
3093 = TypeWithKeyword::getKeywordForTagTypeKind(TagKind);
3095 if (DependentTemplateName *DTN = Template.getAsDependentTemplateName()) {
3096 QualType T = Context.getDependentTemplateSpecializationType(Keyword,
3097 DTN->getQualifier(),
3098 DTN->getIdentifier(),
3101 // Build type-source information.
3103 DependentTemplateSpecializationTypeLoc SpecTL
3104 = TLB.push<DependentTemplateSpecializationTypeLoc>(T);
3105 SpecTL.setElaboratedKeywordLoc(TagLoc);
3106 SpecTL.setQualifierLoc(SS.getWithLocInContext(Context));
3107 SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
3108 SpecTL.setTemplateNameLoc(TemplateLoc);
3109 SpecTL.setLAngleLoc(LAngleLoc);
3110 SpecTL.setRAngleLoc(RAngleLoc);
3111 for (unsigned I = 0, N = SpecTL.getNumArgs(); I != N; ++I)
3112 SpecTL.setArgLocInfo(I, TemplateArgs[I].getLocInfo());
3113 return CreateParsedType(T, TLB.getTypeSourceInfo(Context, T));
3116 if (TypeAliasTemplateDecl *TAT =
3117 dyn_cast_or_null<TypeAliasTemplateDecl>(Template.getAsTemplateDecl())) {
3118 // C++0x [dcl.type.elab]p2:
3119 // If the identifier resolves to a typedef-name or the simple-template-id
3120 // resolves to an alias template specialization, the
3121 // elaborated-type-specifier is ill-formed.
3122 Diag(TemplateLoc, diag::err_tag_reference_non_tag)
3123 << TAT << NTK_TypeAliasTemplate << TagKind;
3124 Diag(TAT->getLocation(), diag::note_declared_at);
3127 QualType Result = CheckTemplateIdType(Template, TemplateLoc, TemplateArgs);
3128 if (Result.isNull())
3129 return TypeResult(true);
3131 // Check the tag kind
3132 if (const RecordType *RT = Result->getAs<RecordType>()) {
3133 RecordDecl *D = RT->getDecl();
3135 IdentifierInfo *Id = D->getIdentifier();
3136 assert(Id && "templated class must have an identifier");
3138 if (!isAcceptableTagRedeclaration(D, TagKind, TUK == TUK_Definition,
3140 Diag(TagLoc, diag::err_use_with_wrong_tag)
3142 << FixItHint::CreateReplacement(SourceRange(TagLoc), D->getKindName());
3143 Diag(D->getLocation(), diag::note_previous_use);
3147 // Provide source-location information for the template specialization.
3149 TemplateSpecializationTypeLoc SpecTL
3150 = TLB.push<TemplateSpecializationTypeLoc>(Result);
3151 SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
3152 SpecTL.setTemplateNameLoc(TemplateLoc);
3153 SpecTL.setLAngleLoc(LAngleLoc);
3154 SpecTL.setRAngleLoc(RAngleLoc);
3155 for (unsigned i = 0, e = SpecTL.getNumArgs(); i != e; ++i)
3156 SpecTL.setArgLocInfo(i, TemplateArgs[i].getLocInfo());
3158 // Construct an elaborated type containing the nested-name-specifier (if any)
3160 Result = Context.getElaboratedType(Keyword, SS.getScopeRep(), Result);
3161 ElaboratedTypeLoc ElabTL = TLB.push<ElaboratedTypeLoc>(Result);
3162 ElabTL.setElaboratedKeywordLoc(TagLoc);
3163 ElabTL.setQualifierLoc(SS.getWithLocInContext(Context));
3164 return CreateParsedType(Result, TLB.getTypeSourceInfo(Context, Result));
3167 static bool CheckTemplateSpecializationScope(Sema &S, NamedDecl *Specialized,
3168 NamedDecl *PrevDecl,
3170 bool IsPartialSpecialization);
3172 static TemplateSpecializationKind getTemplateSpecializationKind(Decl *D);
3174 static bool isTemplateArgumentTemplateParameter(
3175 const TemplateArgument &Arg, unsigned Depth, unsigned Index) {
3176 switch (Arg.getKind()) {
3177 case TemplateArgument::Null:
3178 case TemplateArgument::NullPtr:
3179 case TemplateArgument::Integral:
3180 case TemplateArgument::Declaration:
3181 case TemplateArgument::Pack:
3182 case TemplateArgument::TemplateExpansion:
3185 case TemplateArgument::Type: {
3186 QualType Type = Arg.getAsType();
3187 const TemplateTypeParmType *TPT =
3188 Arg.getAsType()->getAs<TemplateTypeParmType>();
3189 return TPT && !Type.hasQualifiers() &&
3190 TPT->getDepth() == Depth && TPT->getIndex() == Index;
3193 case TemplateArgument::Expression: {
3194 DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Arg.getAsExpr());
3195 if (!DRE || !DRE->getDecl())
3197 const NonTypeTemplateParmDecl *NTTP =
3198 dyn_cast<NonTypeTemplateParmDecl>(DRE->getDecl());
3199 return NTTP && NTTP->getDepth() == Depth && NTTP->getIndex() == Index;
3202 case TemplateArgument::Template:
3203 const TemplateTemplateParmDecl *TTP =
3204 dyn_cast_or_null<TemplateTemplateParmDecl>(
3205 Arg.getAsTemplateOrTemplatePattern().getAsTemplateDecl());
3206 return TTP && TTP->getDepth() == Depth && TTP->getIndex() == Index;
3208 llvm_unreachable("unexpected kind of template argument");
3211 static bool isSameAsPrimaryTemplate(TemplateParameterList *Params,
3212 ArrayRef<TemplateArgument> Args) {
3213 if (Params->size() != Args.size())
3216 unsigned Depth = Params->getDepth();
3218 for (unsigned I = 0, N = Args.size(); I != N; ++I) {
3219 TemplateArgument Arg = Args[I];
3221 // If the parameter is a pack expansion, the argument must be a pack
3222 // whose only element is a pack expansion.
3223 if (Params->getParam(I)->isParameterPack()) {
3224 if (Arg.getKind() != TemplateArgument::Pack || Arg.pack_size() != 1 ||
3225 !Arg.pack_begin()->isPackExpansion())
3227 Arg = Arg.pack_begin()->getPackExpansionPattern();
3230 if (!isTemplateArgumentTemplateParameter(Arg, Depth, I))
3237 /// Convert the parser's template argument list representation into our form.
3238 static TemplateArgumentListInfo
3239 makeTemplateArgumentListInfo(Sema &S, TemplateIdAnnotation &TemplateId) {
3240 TemplateArgumentListInfo TemplateArgs(TemplateId.LAngleLoc,
3241 TemplateId.RAngleLoc);
3242 ASTTemplateArgsPtr TemplateArgsPtr(TemplateId.getTemplateArgs(),
3243 TemplateId.NumArgs);
3244 S.translateTemplateArguments(TemplateArgsPtr, TemplateArgs);
3245 return TemplateArgs;
3248 template<typename PartialSpecDecl>
3249 static void checkMoreSpecializedThanPrimary(Sema &S, PartialSpecDecl *Partial) {
3250 if (Partial->getDeclContext()->isDependentContext())
3253 // FIXME: Get the TDK from deduction in order to provide better diagnostics
3254 // for non-substitution-failure issues?
3255 TemplateDeductionInfo Info(Partial->getLocation());
3256 if (S.isMoreSpecializedThanPrimary(Partial, Info))
3259 auto *Template = Partial->getSpecializedTemplate();
3260 S.Diag(Partial->getLocation(),
3261 diag::ext_partial_spec_not_more_specialized_than_primary)
3262 << isa<VarTemplateDecl>(Template);
3264 if (Info.hasSFINAEDiagnostic()) {
3265 PartialDiagnosticAt Diag = {SourceLocation(),
3266 PartialDiagnostic::NullDiagnostic()};
3267 Info.takeSFINAEDiagnostic(Diag);
3268 SmallString<128> SFINAEArgString;
3269 Diag.second.EmitToString(S.getDiagnostics(), SFINAEArgString);
3271 diag::note_partial_spec_not_more_specialized_than_primary)
3275 S.Diag(Template->getLocation(), diag::note_template_decl_here);
3279 noteNonDeducibleParameters(Sema &S, TemplateParameterList *TemplateParams,
3280 const llvm::SmallBitVector &DeducibleParams) {
3281 for (unsigned I = 0, N = DeducibleParams.size(); I != N; ++I) {
3282 if (!DeducibleParams[I]) {
3283 NamedDecl *Param = cast<NamedDecl>(TemplateParams->getParam(I));
3284 if (Param->getDeclName())
3285 S.Diag(Param->getLocation(), diag::note_non_deducible_parameter)
3286 << Param->getDeclName();
3288 S.Diag(Param->getLocation(), diag::note_non_deducible_parameter)
3295 template<typename PartialSpecDecl>
3296 static void checkTemplatePartialSpecialization(Sema &S,
3297 PartialSpecDecl *Partial) {
3298 // C++1z [temp.class.spec]p8: (DR1495)
3299 // - The specialization shall be more specialized than the primary
3300 // template (14.5.5.2).
3301 checkMoreSpecializedThanPrimary(S, Partial);
3303 // C++ [temp.class.spec]p8: (DR1315)
3304 // - Each template-parameter shall appear at least once in the
3305 // template-id outside a non-deduced context.
3306 // C++1z [temp.class.spec.match]p3 (P0127R2)
3307 // If the template arguments of a partial specialization cannot be
3308 // deduced because of the structure of its template-parameter-list
3309 // and the template-id, the program is ill-formed.
3310 auto *TemplateParams = Partial->getTemplateParameters();
3311 llvm::SmallBitVector DeducibleParams(TemplateParams->size());
3312 S.MarkUsedTemplateParameters(Partial->getTemplateArgs(), true,
3313 TemplateParams->getDepth(), DeducibleParams);
3315 if (!DeducibleParams.all()) {
3316 unsigned NumNonDeducible = DeducibleParams.size() - DeducibleParams.count();
3317 S.Diag(Partial->getLocation(), diag::ext_partial_specs_not_deducible)
3318 << isa<VarTemplatePartialSpecializationDecl>(Partial)
3319 << (NumNonDeducible > 1)
3320 << SourceRange(Partial->getLocation(),
3321 Partial->getTemplateArgsAsWritten()->RAngleLoc);
3322 noteNonDeducibleParameters(S, TemplateParams, DeducibleParams);
3326 void Sema::CheckTemplatePartialSpecialization(
3327 ClassTemplatePartialSpecializationDecl *Partial) {
3328 checkTemplatePartialSpecialization(*this, Partial);
3331 void Sema::CheckTemplatePartialSpecialization(
3332 VarTemplatePartialSpecializationDecl *Partial) {
3333 checkTemplatePartialSpecialization(*this, Partial);
3336 void Sema::CheckDeductionGuideTemplate(FunctionTemplateDecl *TD) {
3337 // C++1z [temp.param]p11:
3338 // A template parameter of a deduction guide template that does not have a
3339 // default-argument shall be deducible from the parameter-type-list of the
3340 // deduction guide template.
3341 auto *TemplateParams = TD->getTemplateParameters();
3342 llvm::SmallBitVector DeducibleParams(TemplateParams->size());
3343 MarkDeducedTemplateParameters(TD, DeducibleParams);
3344 for (unsigned I = 0; I != TemplateParams->size(); ++I) {
3345 // A parameter pack is deducible (to an empty pack).
3346 auto *Param = TemplateParams->getParam(I);
3347 if (Param->isParameterPack() || hasVisibleDefaultArgument(Param))
3348 DeducibleParams[I] = true;
3351 if (!DeducibleParams.all()) {
3352 unsigned NumNonDeducible = DeducibleParams.size() - DeducibleParams.count();
3353 Diag(TD->getLocation(), diag::err_deduction_guide_template_not_deducible)
3354 << (NumNonDeducible > 1);
3355 noteNonDeducibleParameters(*this, TemplateParams, DeducibleParams);
3359 DeclResult Sema::ActOnVarTemplateSpecialization(
3360 Scope *S, Declarator &D, TypeSourceInfo *DI, SourceLocation TemplateKWLoc,
3361 TemplateParameterList *TemplateParams, StorageClass SC,
3362 bool IsPartialSpecialization) {
3363 // D must be variable template id.
3364 assert(D.getName().getKind() == UnqualifiedId::IK_TemplateId &&
3365 "Variable template specialization is declared with a template it.");
3367 TemplateIdAnnotation *TemplateId = D.getName().TemplateId;
3368 TemplateArgumentListInfo TemplateArgs =
3369 makeTemplateArgumentListInfo(*this, *TemplateId);
3370 SourceLocation TemplateNameLoc = D.getIdentifierLoc();
3371 SourceLocation LAngleLoc = TemplateId->LAngleLoc;
3372 SourceLocation RAngleLoc = TemplateId->RAngleLoc;
3374 TemplateName Name = TemplateId->Template.get();
3376 // The template-id must name a variable template.
3377 VarTemplateDecl *VarTemplate =
3378 dyn_cast_or_null<VarTemplateDecl>(Name.getAsTemplateDecl());
3380 NamedDecl *FnTemplate;
3381 if (auto *OTS = Name.getAsOverloadedTemplate())
3382 FnTemplate = *OTS->begin();
3384 FnTemplate = dyn_cast_or_null<FunctionTemplateDecl>(Name.getAsTemplateDecl());
3386 return Diag(D.getIdentifierLoc(), diag::err_var_spec_no_template_but_method)
3387 << FnTemplate->getDeclName();
3388 return Diag(D.getIdentifierLoc(), diag::err_var_spec_no_template)
3389 << IsPartialSpecialization;
3392 // Check for unexpanded parameter packs in any of the template arguments.
3393 for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I)
3394 if (DiagnoseUnexpandedParameterPack(TemplateArgs[I],
3395 UPPC_PartialSpecialization))
3398 // Check that the template argument list is well-formed for this
3400 SmallVector<TemplateArgument, 4> Converted;
3401 if (CheckTemplateArgumentList(VarTemplate, TemplateNameLoc, TemplateArgs,
3405 // Find the variable template (partial) specialization declaration that
3406 // corresponds to these arguments.
3407 if (IsPartialSpecialization) {
3408 if (CheckTemplatePartialSpecializationArgs(TemplateNameLoc, VarTemplate,
3409 TemplateArgs.size(), Converted))
3412 // FIXME: Move these checks to CheckTemplatePartialSpecializationArgs so we
3413 // also do them during instantiation.
3414 bool InstantiationDependent;
3415 if (!Name.isDependent() &&
3416 !TemplateSpecializationType::anyDependentTemplateArguments(
3417 TemplateArgs.arguments(),
3418 InstantiationDependent)) {
3419 Diag(TemplateNameLoc, diag::err_partial_spec_fully_specialized)
3420 << VarTemplate->getDeclName();
3421 IsPartialSpecialization = false;
3424 if (isSameAsPrimaryTemplate(VarTemplate->getTemplateParameters(),
3426 // C++ [temp.class.spec]p9b3:
3428 // -- The argument list of the specialization shall not be identical
3429 // to the implicit argument list of the primary template.
3430 Diag(TemplateNameLoc, diag::err_partial_spec_args_match_primary_template)
3431 << /*variable template*/ 1
3432 << /*is definition*/(SC != SC_Extern && !CurContext->isRecord())
3433 << FixItHint::CreateRemoval(SourceRange(LAngleLoc, RAngleLoc));
3434 // FIXME: Recover from this by treating the declaration as a redeclaration
3435 // of the primary template.
3440 void *InsertPos = nullptr;
3441 VarTemplateSpecializationDecl *PrevDecl = nullptr;
3443 if (IsPartialSpecialization)
3444 // FIXME: Template parameter list matters too
3445 PrevDecl = VarTemplate->findPartialSpecialization(Converted, InsertPos);
3447 PrevDecl = VarTemplate->findSpecialization(Converted, InsertPos);
3449 VarTemplateSpecializationDecl *Specialization = nullptr;
3451 // Check whether we can declare a variable template specialization in
3452 // the current scope.
3453 if (CheckTemplateSpecializationScope(*this, VarTemplate, PrevDecl,
3455 IsPartialSpecialization))
3458 if (PrevDecl && PrevDecl->getSpecializationKind() == TSK_Undeclared) {
3459 // Since the only prior variable template specialization with these
3460 // arguments was referenced but not declared, reuse that
3461 // declaration node as our own, updating its source location and
3462 // the list of outer template parameters to reflect our new declaration.
3463 Specialization = PrevDecl;
3464 Specialization->setLocation(TemplateNameLoc);
3466 } else if (IsPartialSpecialization) {
3467 // Create a new class template partial specialization declaration node.
3468 VarTemplatePartialSpecializationDecl *PrevPartial =
3469 cast_or_null<VarTemplatePartialSpecializationDecl>(PrevDecl);
3470 VarTemplatePartialSpecializationDecl *Partial =
3471 VarTemplatePartialSpecializationDecl::Create(
3472 Context, VarTemplate->getDeclContext(), TemplateKWLoc,
3473 TemplateNameLoc, TemplateParams, VarTemplate, DI->getType(), DI, SC,
3474 Converted, TemplateArgs);
3477 VarTemplate->AddPartialSpecialization(Partial, InsertPos);
3478 Specialization = Partial;
3480 // If we are providing an explicit specialization of a member variable
3481 // template specialization, make a note of that.
3482 if (PrevPartial && PrevPartial->getInstantiatedFromMember())
3483 PrevPartial->setMemberSpecialization();
3485 CheckTemplatePartialSpecialization(Partial);
3487 // Create a new class template specialization declaration node for
3488 // this explicit specialization or friend declaration.
3489 Specialization = VarTemplateSpecializationDecl::Create(
3490 Context, VarTemplate->getDeclContext(), TemplateKWLoc, TemplateNameLoc,
3491 VarTemplate, DI->getType(), DI, SC, Converted);
3492 Specialization->setTemplateArgsInfo(TemplateArgs);
3495 VarTemplate->AddSpecialization(Specialization, InsertPos);
3498 // C++ [temp.expl.spec]p6:
3499 // If a template, a member template or the member of a class template is
3500 // explicitly specialized then that specialization shall be declared
3501 // before the first use of that specialization that would cause an implicit
3502 // instantiation to take place, in every translation unit in which such a
3503 // use occurs; no diagnostic is required.
3504 if (PrevDecl && PrevDecl->getPointOfInstantiation().isValid()) {
3506 for (Decl *Prev = PrevDecl; Prev; Prev = Prev->getPreviousDecl()) {
3507 // Is there any previous explicit specialization declaration?
3508 if (getTemplateSpecializationKind(Prev) == TSK_ExplicitSpecialization) {
3515 SourceRange Range(TemplateNameLoc, RAngleLoc);
3516 Diag(TemplateNameLoc, diag::err_specialization_after_instantiation)
3519 Diag(PrevDecl->getPointOfInstantiation(),
3520 diag::note_instantiation_required_here)
3521 << (PrevDecl->getTemplateSpecializationKind() !=
3522 TSK_ImplicitInstantiation);
3527 Specialization->setTemplateKeywordLoc(TemplateKWLoc);
3528 Specialization->setLexicalDeclContext(CurContext);
3530 // Add the specialization into its lexical context, so that it can
3531 // be seen when iterating through the list of declarations in that
3532 // context. However, specializations are not found by name lookup.
3533 CurContext->addDecl(Specialization);
3535 // Note that this is an explicit specialization.
3536 Specialization->setSpecializationKind(TSK_ExplicitSpecialization);
3539 // Check that this isn't a redefinition of this specialization,
3540 // merging with previous declarations.
3541 LookupResult PrevSpec(*this, GetNameForDeclarator(D), LookupOrdinaryName,
3543 PrevSpec.addDecl(PrevDecl);
3544 D.setRedeclaration(CheckVariableDeclaration(Specialization, PrevSpec));
3545 } else if (Specialization->isStaticDataMember() &&
3546 Specialization->isOutOfLine()) {
3547 Specialization->setAccess(VarTemplate->getAccess());
3550 // Link instantiations of static data members back to the template from
3551 // which they were instantiated.
3552 if (Specialization->isStaticDataMember())
3553 Specialization->setInstantiationOfStaticDataMember(
3554 VarTemplate->getTemplatedDecl(),
3555 Specialization->getSpecializationKind());
3557 return Specialization;
3561 /// \brief A partial specialization whose template arguments have matched
3562 /// a given template-id.
3563 struct PartialSpecMatchResult {
3564 VarTemplatePartialSpecializationDecl *Partial;
3565 TemplateArgumentList *Args;
3567 } // end anonymous namespace
3570 Sema::CheckVarTemplateId(VarTemplateDecl *Template, SourceLocation TemplateLoc,
3571 SourceLocation TemplateNameLoc,
3572 const TemplateArgumentListInfo &TemplateArgs) {
3573 assert(Template && "A variable template id without template?");
3575 // Check that the template argument list is well-formed for this template.
3576 SmallVector<TemplateArgument, 4> Converted;
3577 if (CheckTemplateArgumentList(
3578 Template, TemplateNameLoc,
3579 const_cast<TemplateArgumentListInfo &>(TemplateArgs), false,
3583 // Find the variable template specialization declaration that
3584 // corresponds to these arguments.
3585 void *InsertPos = nullptr;
3586 if (VarTemplateSpecializationDecl *Spec = Template->findSpecialization(
3587 Converted, InsertPos)) {
3588 checkSpecializationVisibility(TemplateNameLoc, Spec);
3589 // If we already have a variable template specialization, return it.
3593 // This is the first time we have referenced this variable template
3594 // specialization. Create the canonical declaration and add it to
3595 // the set of specializations, based on the closest partial specialization
3596 // that it represents. That is,
3597 VarDecl *InstantiationPattern = Template->getTemplatedDecl();
3598 TemplateArgumentList TemplateArgList(TemplateArgumentList::OnStack,
3600 TemplateArgumentList *InstantiationArgs = &TemplateArgList;
3601 bool AmbiguousPartialSpec = false;
3602 typedef PartialSpecMatchResult MatchResult;
3603 SmallVector<MatchResult, 4> Matched;
3604 SourceLocation PointOfInstantiation = TemplateNameLoc;
3605 TemplateSpecCandidateSet FailedCandidates(PointOfInstantiation,
3606 /*ForTakingAddress=*/false);
3608 // 1. Attempt to find the closest partial specialization that this
3609 // specializes, if any.
3610 // If any of the template arguments is dependent, then this is probably
3611 // a placeholder for an incomplete declarative context; which must be
3612 // complete by instantiation time. Thus, do not search through the partial
3613 // specializations yet.
3614 // TODO: Unify with InstantiateClassTemplateSpecialization()?
3615 // Perhaps better after unification of DeduceTemplateArguments() and
3616 // getMoreSpecializedPartialSpecialization().
3617 bool InstantiationDependent = false;
3618 if (!TemplateSpecializationType::anyDependentTemplateArguments(
3619 TemplateArgs, InstantiationDependent)) {
3621 SmallVector<VarTemplatePartialSpecializationDecl *, 4> PartialSpecs;
3622 Template->getPartialSpecializations(PartialSpecs);
3624 for (unsigned I = 0, N = PartialSpecs.size(); I != N; ++I) {
3625 VarTemplatePartialSpecializationDecl *Partial = PartialSpecs[I];
3626 TemplateDeductionInfo Info(FailedCandidates.getLocation());
3628 if (TemplateDeductionResult Result =
3629 DeduceTemplateArguments(Partial, TemplateArgList, Info)) {
3630 // Store the failed-deduction information for use in diagnostics, later.
3631 // TODO: Actually use the failed-deduction info?
3632 FailedCandidates.addCandidate().set(
3633 DeclAccessPair::make(Template, AS_public), Partial,
3634 MakeDeductionFailureInfo(Context, Result, Info));
3637 Matched.push_back(PartialSpecMatchResult());
3638 Matched.back().Partial = Partial;
3639 Matched.back().Args = Info.take();
3643 if (Matched.size() >= 1) {
3644 SmallVector<MatchResult, 4>::iterator Best = Matched.begin();
3645 if (Matched.size() == 1) {
3646 // -- If exactly one matching specialization is found, the
3647 // instantiation is generated from that specialization.
3648 // We don't need to do anything for this.
3650 // -- If more than one matching specialization is found, the
3651 // partial order rules (14.5.4.2) are used to determine
3652 // whether one of the specializations is more specialized
3653 // than the others. If none of the specializations is more
3654 // specialized than all of the other matching
3655 // specializations, then the use of the variable template is
3656 // ambiguous and the program is ill-formed.
3657 for (SmallVector<MatchResult, 4>::iterator P = Best + 1,
3658 PEnd = Matched.end();
3660 if (getMoreSpecializedPartialSpecialization(P->Partial, Best->Partial,
3661 PointOfInstantiation) ==
3666 // Determine if the best partial specialization is more specialized than
3668 for (SmallVector<MatchResult, 4>::iterator P = Matched.begin(),
3669 PEnd = Matched.end();
3671 if (P != Best && getMoreSpecializedPartialSpecialization(
3672 P->Partial, Best->Partial,
3673 PointOfInstantiation) != Best->Partial) {
3674 AmbiguousPartialSpec = true;
3680 // Instantiate using the best variable template partial specialization.
3681 InstantiationPattern = Best->Partial;
3682 InstantiationArgs = Best->Args;
3684 // -- If no match is found, the instantiation is generated
3685 // from the primary template.
3686 // InstantiationPattern = Template->getTemplatedDecl();
3690 // 2. Create the canonical declaration.
3691 // Note that we do not instantiate a definition until we see an odr-use
3692 // in DoMarkVarDeclReferenced().
3693 // FIXME: LateAttrs et al.?
3694 VarTemplateSpecializationDecl *Decl = BuildVarTemplateInstantiation(
3695 Template, InstantiationPattern, *InstantiationArgs, TemplateArgs,
3696 Converted, TemplateNameLoc, InsertPos /*, LateAttrs, StartingScope*/);
3700 if (AmbiguousPartialSpec) {
3701 // Partial ordering did not produce a clear winner. Complain.
3702 Decl->setInvalidDecl();
3703 Diag(PointOfInstantiation, diag::err_partial_spec_ordering_ambiguous)
3706 // Print the matching partial specializations.
3707 for (MatchResult P : Matched)
3708 Diag(P.Partial->getLocation(), diag::note_partial_spec_match)
3709 << getTemplateArgumentBindingsText(P.Partial->getTemplateParameters(),
3714 if (VarTemplatePartialSpecializationDecl *D =
3715 dyn_cast<VarTemplatePartialSpecializationDecl>(InstantiationPattern))
3716 Decl->setInstantiationOf(D, InstantiationArgs);
3718 checkSpecializationVisibility(TemplateNameLoc, Decl);
3720 assert(Decl && "No variable template specialization?");
3725 Sema::CheckVarTemplateId(const CXXScopeSpec &SS,
3726 const DeclarationNameInfo &NameInfo,
3727 VarTemplateDecl *Template, SourceLocation TemplateLoc,
3728 const TemplateArgumentListInfo *TemplateArgs) {
3730 DeclResult Decl = CheckVarTemplateId(Template, TemplateLoc, NameInfo.getLoc(),
3732 if (Decl.isInvalid())
3735 VarDecl *Var = cast<VarDecl>(Decl.get());
3736 if (!Var->getTemplateSpecializationKind())
3737 Var->setTemplateSpecializationKind(TSK_ImplicitInstantiation,
3740 // Build an ordinary singleton decl ref.
3741 return BuildDeclarationNameExpr(SS, NameInfo, Var,
3742 /*FoundD=*/nullptr, TemplateArgs);
3745 ExprResult Sema::BuildTemplateIdExpr(const CXXScopeSpec &SS,
3746 SourceLocation TemplateKWLoc,
3749 const TemplateArgumentListInfo *TemplateArgs) {
3750 // FIXME: Can we do any checking at this point? I guess we could check the
3751 // template arguments that we have against the template name, if the template
3752 // name refers to a single template. That's not a terribly common case,
3754 // foo<int> could identify a single function unambiguously
3755 // This approach does NOT work, since f<int>(1);
3756 // gets resolved prior to resorting to overload resolution
3757 // i.e., template<class T> void f(double);
3758 // vs template<class T, class U> void f(U);
3760 // These should be filtered out by our callers.
3761 assert(!R.empty() && "empty lookup results when building templateid");
3762 assert(!R.isAmbiguous() && "ambiguous lookup when building templateid");
3764 // In C++1y, check variable template ids.
3765 bool InstantiationDependent;
3766 if (R.getAsSingle<VarTemplateDecl>() &&
3767 !TemplateSpecializationType::anyDependentTemplateArguments(
3768 *TemplateArgs, InstantiationDependent)) {
3769 return CheckVarTemplateId(SS, R.getLookupNameInfo(),
3770 R.getAsSingle<VarTemplateDecl>(),
3771 TemplateKWLoc, TemplateArgs);
3774 // We don't want lookup warnings at this point.
3775 R.suppressDiagnostics();
3777 UnresolvedLookupExpr *ULE
3778 = UnresolvedLookupExpr::Create(Context, R.getNamingClass(),
3779 SS.getWithLocInContext(Context),
3781 R.getLookupNameInfo(),
3782 RequiresADL, TemplateArgs,
3783 R.begin(), R.end());
3788 // We actually only call this from template instantiation.
3790 Sema::BuildQualifiedTemplateIdExpr(CXXScopeSpec &SS,
3791 SourceLocation TemplateKWLoc,
3792 const DeclarationNameInfo &NameInfo,
3793 const TemplateArgumentListInfo *TemplateArgs) {
3795 assert(TemplateArgs || TemplateKWLoc.isValid());
3797 if (!(DC = computeDeclContext(SS, false)) ||
3798 DC->isDependentContext() ||
3799 RequireCompleteDeclContext(SS, DC))
3800 return BuildDependentDeclRefExpr(SS, TemplateKWLoc, NameInfo, TemplateArgs);
3802 bool MemberOfUnknownSpecialization;
3803 LookupResult R(*this, NameInfo, LookupOrdinaryName);
3804 LookupTemplateName(R, (Scope*)nullptr, SS, QualType(), /*Entering*/ false,
3805 MemberOfUnknownSpecialization);
3807 if (R.isAmbiguous())
3811 Diag(NameInfo.getLoc(), diag::err_template_kw_refers_to_non_template)
3812 << NameInfo.getName() << SS.getRange();
3816 if (ClassTemplateDecl *Temp = R.getAsSingle<ClassTemplateDecl>()) {
3817 Diag(NameInfo.getLoc(), diag::err_template_kw_refers_to_class_template)
3819 << NameInfo.getName().getAsString() << SS.getRange();
3820 Diag(Temp->getLocation(), diag::note_referenced_class_template);
3824 return BuildTemplateIdExpr(SS, TemplateKWLoc, R, /*ADL*/ false, TemplateArgs);
3827 /// \brief Form a dependent template name.
3829 /// This action forms a dependent template name given the template
3830 /// name and its (presumably dependent) scope specifier. For
3831 /// example, given "MetaFun::template apply", the scope specifier \p
3832 /// SS will be "MetaFun::", \p TemplateKWLoc contains the location
3833 /// of the "template" keyword, and "apply" is the \p Name.
3834 TemplateNameKind Sema::ActOnDependentTemplateName(Scope *S,
3836 SourceLocation TemplateKWLoc,
3837 UnqualifiedId &Name,
3838 ParsedType ObjectType,
3839 bool EnteringContext,
3841 bool AllowInjectedClassName) {
3842 if (TemplateKWLoc.isValid() && S && !S->getTemplateParamParent())
3844 getLangOpts().CPlusPlus11 ?
3845 diag::warn_cxx98_compat_template_outside_of_template :
3846 diag::ext_template_outside_of_template)
3847 << FixItHint::CreateRemoval(TemplateKWLoc);
3849 DeclContext *LookupCtx = nullptr;
3851 LookupCtx = computeDeclContext(SS, EnteringContext);
3852 if (!LookupCtx && ObjectType)
3853 LookupCtx = computeDeclContext(ObjectType.get());
3855 // C++0x [temp.names]p5:
3856 // If a name prefixed by the keyword template is not the name of
3857 // a template, the program is ill-formed. [Note: the keyword
3858 // template may not be applied to non-template members of class
3859 // templates. -end note ] [ Note: as is the case with the
3860 // typename prefix, the template prefix is allowed in cases
3861 // where it is not strictly necessary; i.e., when the
3862 // nested-name-specifier or the expression on the left of the ->
3863 // or . is not dependent on a template-parameter, or the use
3864 // does not appear in the scope of a template. -end note]
3866 // Note: C++03 was more strict here, because it banned the use of
3867 // the "template" keyword prior to a template-name that was not a
3868 // dependent name. C++ DR468 relaxed this requirement (the
3869 // "template" keyword is now permitted). We follow the C++0x
3870 // rules, even in C++03 mode with a warning, retroactively applying the DR.
3871 bool MemberOfUnknownSpecialization;
3872 TemplateNameKind TNK = isTemplateName(S, SS, TemplateKWLoc.isValid(), Name,
3873 ObjectType, EnteringContext, Result,
3874 MemberOfUnknownSpecialization);
3875 if (TNK == TNK_Non_template && LookupCtx->isDependentContext() &&
3876 isa<CXXRecordDecl>(LookupCtx) &&
3877 (!cast<CXXRecordDecl>(LookupCtx)->hasDefinition() ||
3878 cast<CXXRecordDecl>(LookupCtx)->hasAnyDependentBases())) {
3879 // This is a dependent template. Handle it below.
3880 } else if (TNK == TNK_Non_template) {
3881 Diag(Name.getLocStart(),
3882 diag::err_template_kw_refers_to_non_template)
3883 << GetNameFromUnqualifiedId(Name).getName()
3884 << Name.getSourceRange()
3886 return TNK_Non_template;
3888 // We found something; return it.
3889 auto *LookupRD = dyn_cast<CXXRecordDecl>(LookupCtx);
3890 if (!AllowInjectedClassName && SS.isSet() && LookupRD &&
3891 Name.getKind() == UnqualifiedId::IK_Identifier && Name.Identifier &&
3892 LookupRD->getIdentifier() == Name.Identifier) {
3893 // C++14 [class.qual]p2:
3894 // In a lookup in which function names are not ignored and the
3895 // nested-name-specifier nominates a class C, if the name specified
3896 // [...] is the injected-class-name of C, [...] the name is instead
3897 // considered to name the constructor
3899 // We don't get here if naming the constructor would be valid, so we
3900 // just reject immediately and recover by treating the
3901 // injected-class-name as naming the template.
3902 Diag(Name.getLocStart(),
3903 diag::ext_out_of_line_qualified_id_type_names_constructor)
3904 << Name.Identifier << 0 /*injected-class-name used as template name*/
3905 << 1 /*'template' keyword was used*/;
3911 NestedNameSpecifier *Qualifier = SS.getScopeRep();
3913 switch (Name.getKind()) {
3914 case UnqualifiedId::IK_Identifier:
3915 Result = TemplateTy::make(Context.getDependentTemplateName(Qualifier,
3917 return TNK_Dependent_template_name;
3919 case UnqualifiedId::IK_OperatorFunctionId:
3920 Result = TemplateTy::make(Context.getDependentTemplateName(Qualifier,
3921 Name.OperatorFunctionId.Operator));
3922 return TNK_Function_template;
3924 case UnqualifiedId::IK_LiteralOperatorId:
3925 llvm_unreachable("literal operator id cannot have a dependent scope");
3931 Diag(Name.getLocStart(),
3932 diag::err_template_kw_refers_to_non_template)
3933 << GetNameFromUnqualifiedId(Name).getName()
3934 << Name.getSourceRange()
3936 return TNK_Non_template;
3939 bool Sema::CheckTemplateTypeArgument(TemplateTypeParmDecl *Param,
3940 TemplateArgumentLoc &AL,
3941 SmallVectorImpl<TemplateArgument> &Converted) {
3942 const TemplateArgument &Arg = AL.getArgument();
3944 TypeSourceInfo *TSI = nullptr;
3946 // Check template type parameter.
3947 switch(Arg.getKind()) {
3948 case TemplateArgument::Type:
3949 // C++ [temp.arg.type]p1:
3950 // A template-argument for a template-parameter which is a
3951 // type shall be a type-id.
3952 ArgType = Arg.getAsType();
3953 TSI = AL.getTypeSourceInfo();
3955 case TemplateArgument::Template: {
3956 // We have a template type parameter but the template argument
3957 // is a template without any arguments.
3958 SourceRange SR = AL.getSourceRange();
3959 TemplateName Name = Arg.getAsTemplate();
3960 Diag(SR.getBegin(), diag::err_template_missing_args)
3961 << (int)getTemplateNameKindForDiagnostics(Name) << Name << SR;
3962 if (TemplateDecl *Decl = Name.getAsTemplateDecl())
3963 Diag(Decl->getLocation(), diag::note_template_decl_here);
3967 case TemplateArgument::Expression: {
3968 // We have a template type parameter but the template argument is an
3969 // expression; see if maybe it is missing the "typename" keyword.
3971 DeclarationNameInfo NameInfo;
3973 if (DeclRefExpr *ArgExpr = dyn_cast<DeclRefExpr>(Arg.getAsExpr())) {
3974 SS.Adopt(ArgExpr->getQualifierLoc());
3975 NameInfo = ArgExpr->getNameInfo();
3976 } else if (DependentScopeDeclRefExpr *ArgExpr =
3977 dyn_cast<DependentScopeDeclRefExpr>(Arg.getAsExpr())) {
3978 SS.Adopt(ArgExpr->getQualifierLoc());
3979 NameInfo = ArgExpr->getNameInfo();
3980 } else if (CXXDependentScopeMemberExpr *ArgExpr =
3981 dyn_cast<CXXDependentScopeMemberExpr>(Arg.getAsExpr())) {
3982 if (ArgExpr->isImplicitAccess()) {
3983 SS.Adopt(ArgExpr->getQualifierLoc());
3984 NameInfo = ArgExpr->getMemberNameInfo();
3988 if (auto *II = NameInfo.getName().getAsIdentifierInfo()) {
3989 LookupResult Result(*this, NameInfo, LookupOrdinaryName);
3990 LookupParsedName(Result, CurScope, &SS);
3992 if (Result.getAsSingle<TypeDecl>() ||
3993 Result.getResultKind() ==
3994 LookupResult::NotFoundInCurrentInstantiation) {
3995 // Suggest that the user add 'typename' before the NNS.
3996 SourceLocation Loc = AL.getSourceRange().getBegin();
3997 Diag(Loc, getLangOpts().MSVCCompat
3998 ? diag::ext_ms_template_type_arg_missing_typename
3999 : diag::err_template_arg_must_be_type_suggest)
4000 << FixItHint::CreateInsertion(Loc, "typename ");
4001 Diag(Param->getLocation(), diag::note_template_param_here);
4003 // Recover by synthesizing a type using the location information that we
4006 Context.getDependentNameType(ETK_Typename, SS.getScopeRep(), II);
4008 DependentNameTypeLoc TL = TLB.push<DependentNameTypeLoc>(ArgType);
4009 TL.setElaboratedKeywordLoc(SourceLocation(/*synthesized*/));
4010 TL.setQualifierLoc(SS.getWithLocInContext(Context));
4011 TL.setNameLoc(NameInfo.getLoc());
4012 TSI = TLB.getTypeSourceInfo(Context, ArgType);
4014 // Overwrite our input TemplateArgumentLoc so that we can recover
4016 AL = TemplateArgumentLoc(TemplateArgument(ArgType),
4017 TemplateArgumentLocInfo(TSI));
4025 // We have a template type parameter but the template argument
4027 SourceRange SR = AL.getSourceRange();
4028 Diag(SR.getBegin(), diag::err_template_arg_must_be_type) << SR;
4029 Diag(Param->getLocation(), diag::note_template_param_here);
4035 if (CheckTemplateArgument(Param, TSI))
4038 // Add the converted template type argument.
4039 ArgType = Context.getCanonicalType(ArgType);
4042 // If an explicitly-specified template argument type is a lifetime type
4043 // with no lifetime qualifier, the __strong lifetime qualifier is inferred.
4044 if (getLangOpts().ObjCAutoRefCount &&
4045 ArgType->isObjCLifetimeType() &&
4046 !ArgType.getObjCLifetime()) {
4048 Qs.setObjCLifetime(Qualifiers::OCL_Strong);
4049 ArgType = Context.getQualifiedType(ArgType, Qs);
4052 Converted.push_back(TemplateArgument(ArgType));
4056 /// \brief Substitute template arguments into the default template argument for
4057 /// the given template type parameter.
4059 /// \param SemaRef the semantic analysis object for which we are performing
4060 /// the substitution.
4062 /// \param Template the template that we are synthesizing template arguments
4065 /// \param TemplateLoc the location of the template name that started the
4066 /// template-id we are checking.
4068 /// \param RAngleLoc the location of the right angle bracket ('>') that
4069 /// terminates the template-id.
4071 /// \param Param the template template parameter whose default we are
4072 /// substituting into.
4074 /// \param Converted the list of template arguments provided for template
4075 /// parameters that precede \p Param in the template parameter list.
4076 /// \returns the substituted template argument, or NULL if an error occurred.
4077 static TypeSourceInfo *
4078 SubstDefaultTemplateArgument(Sema &SemaRef,
4079 TemplateDecl *Template,
4080 SourceLocation TemplateLoc,
4081 SourceLocation RAngleLoc,
4082 TemplateTypeParmDecl *Param,
4083 SmallVectorImpl<TemplateArgument> &Converted) {
4084 TypeSourceInfo *ArgType = Param->getDefaultArgumentInfo();
4086 // If the argument type is dependent, instantiate it now based
4087 // on the previously-computed template arguments.
4088 if (ArgType->getType()->isDependentType()) {
4089 Sema::InstantiatingTemplate Inst(SemaRef, TemplateLoc,
4090 Param, Template, Converted,
4091 SourceRange(TemplateLoc, RAngleLoc));
4092 if (Inst.isInvalid())
4095 TemplateArgumentList TemplateArgs(TemplateArgumentList::OnStack, Converted);
4097 // Only substitute for the innermost template argument list.
4098 MultiLevelTemplateArgumentList TemplateArgLists;
4099 TemplateArgLists.addOuterTemplateArguments(&TemplateArgs);
4100 for (unsigned i = 0, e = Param->getDepth(); i != e; ++i)
4101 TemplateArgLists.addOuterTemplateArguments(None);
4103 Sema::ContextRAII SavedContext(SemaRef, Template->getDeclContext());
4105 SemaRef.SubstType(ArgType, TemplateArgLists,
4106 Param->getDefaultArgumentLoc(), Param->getDeclName());
4112 /// \brief Substitute template arguments into the default template argument for
4113 /// the given non-type template parameter.
4115 /// \param SemaRef the semantic analysis object for which we are performing
4116 /// the substitution.
4118 /// \param Template the template that we are synthesizing template arguments
4121 /// \param TemplateLoc the location of the template name that started the
4122 /// template-id we are checking.
4124 /// \param RAngleLoc the location of the right angle bracket ('>') that
4125 /// terminates the template-id.
4127 /// \param Param the non-type template parameter whose default we are
4128 /// substituting into.
4130 /// \param Converted the list of template arguments provided for template
4131 /// parameters that precede \p Param in the template parameter list.
4133 /// \returns the substituted template argument, or NULL if an error occurred.
4135 SubstDefaultTemplateArgument(Sema &SemaRef,
4136 TemplateDecl *Template,
4137 SourceLocation TemplateLoc,
4138 SourceLocation RAngleLoc,
4139 NonTypeTemplateParmDecl *Param,
4140 SmallVectorImpl<TemplateArgument> &Converted) {
4141 Sema::InstantiatingTemplate Inst(SemaRef, TemplateLoc,
4142 Param, Template, Converted,
4143 SourceRange(TemplateLoc, RAngleLoc));
4144 if (Inst.isInvalid())
4147 TemplateArgumentList TemplateArgs(TemplateArgumentList::OnStack, Converted);
4149 // Only substitute for the innermost template argument list.
4150 MultiLevelTemplateArgumentList TemplateArgLists;
4151 TemplateArgLists.addOuterTemplateArguments(&TemplateArgs);
4152 for (unsigned i = 0, e = Param->getDepth(); i != e; ++i)
4153 TemplateArgLists.addOuterTemplateArguments(None);
4155 EnterExpressionEvaluationContext ConstantEvaluated(
4156 SemaRef, Sema::ExpressionEvaluationContext::ConstantEvaluated);
4157 return SemaRef.SubstExpr(Param->getDefaultArgument(), TemplateArgLists);
4160 /// \brief Substitute template arguments into the default template argument for
4161 /// the given template template parameter.
4163 /// \param SemaRef the semantic analysis object for which we are performing
4164 /// the substitution.
4166 /// \param Template the template that we are synthesizing template arguments
4169 /// \param TemplateLoc the location of the template name that started the
4170 /// template-id we are checking.
4172 /// \param RAngleLoc the location of the right angle bracket ('>') that
4173 /// terminates the template-id.
4175 /// \param Param the template template parameter whose default we are
4176 /// substituting into.
4178 /// \param Converted the list of template arguments provided for template
4179 /// parameters that precede \p Param in the template parameter list.
4181 /// \param QualifierLoc Will be set to the nested-name-specifier (with
4182 /// source-location information) that precedes the template name.
4184 /// \returns the substituted template argument, or NULL if an error occurred.
4186 SubstDefaultTemplateArgument(Sema &SemaRef,
4187 TemplateDecl *Template,
4188 SourceLocation TemplateLoc,
4189 SourceLocation RAngleLoc,
4190 TemplateTemplateParmDecl *Param,
4191 SmallVectorImpl<TemplateArgument> &Converted,
4192 NestedNameSpecifierLoc &QualifierLoc) {
4193 Sema::InstantiatingTemplate Inst(
4194 SemaRef, TemplateLoc, TemplateParameter(Param), Template, Converted,
4195 SourceRange(TemplateLoc, RAngleLoc));
4196 if (Inst.isInvalid())
4197 return TemplateName();
4199 TemplateArgumentList TemplateArgs(TemplateArgumentList::OnStack, Converted);
4201 // Only substitute for the innermost template argument list.
4202 MultiLevelTemplateArgumentList TemplateArgLists;
4203 TemplateArgLists.addOuterTemplateArguments(&TemplateArgs);
4204 for (unsigned i = 0, e = Param->getDepth(); i != e; ++i)
4205 TemplateArgLists.addOuterTemplateArguments(None);
4207 Sema::ContextRAII SavedContext(SemaRef, Template->getDeclContext());
4208 // Substitute into the nested-name-specifier first,
4209 QualifierLoc = Param->getDefaultArgument().getTemplateQualifierLoc();
4212 SemaRef.SubstNestedNameSpecifierLoc(QualifierLoc, TemplateArgLists);
4214 return TemplateName();
4217 return SemaRef.SubstTemplateName(
4219 Param->getDefaultArgument().getArgument().getAsTemplate(),
4220 Param->getDefaultArgument().getTemplateNameLoc(),
4224 /// \brief If the given template parameter has a default template
4225 /// argument, substitute into that default template argument and
4226 /// return the corresponding template argument.
4228 Sema::SubstDefaultTemplateArgumentIfAvailable(TemplateDecl *Template,
4229 SourceLocation TemplateLoc,
4230 SourceLocation RAngleLoc,
4232 SmallVectorImpl<TemplateArgument>
4234 bool &HasDefaultArg) {
4235 HasDefaultArg = false;
4237 if (TemplateTypeParmDecl *TypeParm = dyn_cast<TemplateTypeParmDecl>(Param)) {
4238 if (!hasVisibleDefaultArgument(TypeParm))
4239 return TemplateArgumentLoc();
4241 HasDefaultArg = true;
4242 TypeSourceInfo *DI = SubstDefaultTemplateArgument(*this, Template,
4248 return TemplateArgumentLoc(TemplateArgument(DI->getType()), DI);
4250 return TemplateArgumentLoc();
4253 if (NonTypeTemplateParmDecl *NonTypeParm
4254 = dyn_cast<NonTypeTemplateParmDecl>(Param)) {
4255 if (!hasVisibleDefaultArgument(NonTypeParm))
4256 return TemplateArgumentLoc();
4258 HasDefaultArg = true;
4259 ExprResult Arg = SubstDefaultTemplateArgument(*this, Template,
4264 if (Arg.isInvalid())
4265 return TemplateArgumentLoc();
4267 Expr *ArgE = Arg.getAs<Expr>();
4268 return TemplateArgumentLoc(TemplateArgument(ArgE), ArgE);
4271 TemplateTemplateParmDecl *TempTempParm
4272 = cast<TemplateTemplateParmDecl>(Param);
4273 if (!hasVisibleDefaultArgument(TempTempParm))
4274 return TemplateArgumentLoc();
4276 HasDefaultArg = true;
4277 NestedNameSpecifierLoc QualifierLoc;
4278 TemplateName TName = SubstDefaultTemplateArgument(*this, Template,
4285 return TemplateArgumentLoc();
4287 return TemplateArgumentLoc(TemplateArgument(TName),
4288 TempTempParm->getDefaultArgument().getTemplateQualifierLoc(),
4289 TempTempParm->getDefaultArgument().getTemplateNameLoc());
4292 /// Convert a template-argument that we parsed as a type into a template, if
4293 /// possible. C++ permits injected-class-names to perform dual service as
4294 /// template template arguments and as template type arguments.
4295 static TemplateArgumentLoc convertTypeTemplateArgumentToTemplate(TypeLoc TLoc) {
4296 // Extract and step over any surrounding nested-name-specifier.
4297 NestedNameSpecifierLoc QualLoc;
4298 if (auto ETLoc = TLoc.getAs<ElaboratedTypeLoc>()) {
4299 if (ETLoc.getTypePtr()->getKeyword() != ETK_None)
4300 return TemplateArgumentLoc();
4302 QualLoc = ETLoc.getQualifierLoc();
4303 TLoc = ETLoc.getNamedTypeLoc();
4306 // If this type was written as an injected-class-name, it can be used as a
4307 // template template argument.
4308 if (auto InjLoc = TLoc.getAs<InjectedClassNameTypeLoc>())
4309 return TemplateArgumentLoc(InjLoc.getTypePtr()->getTemplateName(),
4310 QualLoc, InjLoc.getNameLoc());
4312 // If this type was written as an injected-class-name, it may have been
4313 // converted to a RecordType during instantiation. If the RecordType is
4314 // *not* wrapped in a TemplateSpecializationType and denotes a class
4315 // template specialization, it must have come from an injected-class-name.
4316 if (auto RecLoc = TLoc.getAs<RecordTypeLoc>())
4318 dyn_cast<ClassTemplateSpecializationDecl>(RecLoc.getDecl()))
4319 return TemplateArgumentLoc(TemplateName(CTSD->getSpecializedTemplate()),
4320 QualLoc, RecLoc.getNameLoc());
4322 return TemplateArgumentLoc();
4325 /// \brief Check that the given template argument corresponds to the given
4326 /// template parameter.
4328 /// \param Param The template parameter against which the argument will be
4331 /// \param Arg The template argument, which may be updated due to conversions.
4333 /// \param Template The template in which the template argument resides.
4335 /// \param TemplateLoc The location of the template name for the template
4336 /// whose argument list we're matching.
4338 /// \param RAngleLoc The location of the right angle bracket ('>') that closes
4339 /// the template argument list.
4341 /// \param ArgumentPackIndex The index into the argument pack where this
4342 /// argument will be placed. Only valid if the parameter is a parameter pack.
4344 /// \param Converted The checked, converted argument will be added to the
4345 /// end of this small vector.
4347 /// \param CTAK Describes how we arrived at this particular template argument:
4348 /// explicitly written, deduced, etc.
4350 /// \returns true on error, false otherwise.
4351 bool Sema::CheckTemplateArgument(NamedDecl *Param,
4352 TemplateArgumentLoc &Arg,
4353 NamedDecl *Template,
4354 SourceLocation TemplateLoc,
4355 SourceLocation RAngleLoc,
4356 unsigned ArgumentPackIndex,
4357 SmallVectorImpl<TemplateArgument> &Converted,
4358 CheckTemplateArgumentKind CTAK) {
4359 // Check template type parameters.
4360 if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(Param))
4361 return CheckTemplateTypeArgument(TTP, Arg, Converted);
4363 // Check non-type template parameters.
4364 if (NonTypeTemplateParmDecl *NTTP =dyn_cast<NonTypeTemplateParmDecl>(Param)) {
4365 // Do substitution on the type of the non-type template parameter
4366 // with the template arguments we've seen thus far. But if the
4367 // template has a dependent context then we cannot substitute yet.
4368 QualType NTTPType = NTTP->getType();
4369 if (NTTP->isParameterPack() && NTTP->isExpandedParameterPack())
4370 NTTPType = NTTP->getExpansionType(ArgumentPackIndex);
4372 if (NTTPType->isDependentType() &&
4373 !isa<TemplateTemplateParmDecl>(Template) &&
4374 !Template->getDeclContext()->isDependentContext()) {
4375 // Do substitution on the type of the non-type template parameter.
4376 InstantiatingTemplate Inst(*this, TemplateLoc, Template,
4378 SourceRange(TemplateLoc, RAngleLoc));
4379 if (Inst.isInvalid())
4382 TemplateArgumentList TemplateArgs(TemplateArgumentList::OnStack,
4384 NTTPType = SubstType(NTTPType,
4385 MultiLevelTemplateArgumentList(TemplateArgs),
4386 NTTP->getLocation(),
4387 NTTP->getDeclName());
4388 // If that worked, check the non-type template parameter type
4390 if (!NTTPType.isNull())
4391 NTTPType = CheckNonTypeTemplateParameterType(NTTPType,
4392 NTTP->getLocation());
4393 if (NTTPType.isNull())
4397 switch (Arg.getArgument().getKind()) {
4398 case TemplateArgument::Null:
4399 llvm_unreachable("Should never see a NULL template argument here");
4401 case TemplateArgument::Expression: {
4402 TemplateArgument Result;
4404 CheckTemplateArgument(NTTP, NTTPType, Arg.getArgument().getAsExpr(),
4406 if (Res.isInvalid())
4409 // If the resulting expression is new, then use it in place of the
4410 // old expression in the template argument.
4411 if (Res.get() != Arg.getArgument().getAsExpr()) {
4412 TemplateArgument TA(Res.get());
4413 Arg = TemplateArgumentLoc(TA, Res.get());
4416 Converted.push_back(Result);
4420 case TemplateArgument::Declaration:
4421 case TemplateArgument::Integral:
4422 case TemplateArgument::NullPtr:
4423 // We've already checked this template argument, so just copy
4424 // it to the list of converted arguments.
4425 Converted.push_back(Arg.getArgument());
4428 case TemplateArgument::Template:
4429 case TemplateArgument::TemplateExpansion:
4430 // We were given a template template argument. It may not be ill-formed;
4432 if (DependentTemplateName *DTN
4433 = Arg.getArgument().getAsTemplateOrTemplatePattern()
4434 .getAsDependentTemplateName()) {
4435 // We have a template argument such as \c T::template X, which we
4436 // parsed as a template template argument. However, since we now
4437 // know that we need a non-type template argument, convert this
4438 // template name into an expression.
4440 DeclarationNameInfo NameInfo(DTN->getIdentifier(),
4441 Arg.getTemplateNameLoc());
4444 SS.Adopt(Arg.getTemplateQualifierLoc());
4445 // FIXME: the template-template arg was a DependentTemplateName,
4446 // so it was provided with a template keyword. However, its source
4447 // location is not stored in the template argument structure.
4448 SourceLocation TemplateKWLoc;
4449 ExprResult E = DependentScopeDeclRefExpr::Create(
4450 Context, SS.getWithLocInContext(Context), TemplateKWLoc, NameInfo,
4453 // If we parsed the template argument as a pack expansion, create a
4454 // pack expansion expression.
4455 if (Arg.getArgument().getKind() == TemplateArgument::TemplateExpansion){
4456 E = ActOnPackExpansion(E.get(), Arg.getTemplateEllipsisLoc());
4461 TemplateArgument Result;
4462 E = CheckTemplateArgument(NTTP, NTTPType, E.get(), Result);
4466 Converted.push_back(Result);
4470 // We have a template argument that actually does refer to a class
4471 // template, alias template, or template template parameter, and
4472 // therefore cannot be a non-type template argument.
4473 Diag(Arg.getLocation(), diag::err_template_arg_must_be_expr)
4474 << Arg.getSourceRange();
4476 Diag(Param->getLocation(), diag::note_template_param_here);
4479 case TemplateArgument::Type: {
4480 // We have a non-type template parameter but the template
4481 // argument is a type.
4483 // C++ [temp.arg]p2:
4484 // In a template-argument, an ambiguity between a type-id and
4485 // an expression is resolved to a type-id, regardless of the
4486 // form of the corresponding template-parameter.
4488 // We warn specifically about this case, since it can be rather
4489 // confusing for users.
4490 QualType T = Arg.getArgument().getAsType();
4491 SourceRange SR = Arg.getSourceRange();
4492 if (T->isFunctionType())
4493 Diag(SR.getBegin(), diag::err_template_arg_nontype_ambig) << SR << T;
4495 Diag(SR.getBegin(), diag::err_template_arg_must_be_expr) << SR;
4496 Diag(Param->getLocation(), diag::note_template_param_here);
4500 case TemplateArgument::Pack:
4501 llvm_unreachable("Caller must expand template argument packs");
4508 // Check template template parameters.
4509 TemplateTemplateParmDecl *TempParm = cast<TemplateTemplateParmDecl>(Param);
4511 // Substitute into the template parameter list of the template
4512 // template parameter, since previously-supplied template arguments
4513 // may appear within the template template parameter.
4515 // Set up a template instantiation context.
4516 LocalInstantiationScope Scope(*this);
4517 InstantiatingTemplate Inst(*this, TemplateLoc, Template,
4518 TempParm, Converted,
4519 SourceRange(TemplateLoc, RAngleLoc));
4520 if (Inst.isInvalid())
4523 TemplateArgumentList TemplateArgs(TemplateArgumentList::OnStack, Converted);
4524 TempParm = cast_or_null<TemplateTemplateParmDecl>(
4525 SubstDecl(TempParm, CurContext,
4526 MultiLevelTemplateArgumentList(TemplateArgs)));
4531 // C++1z [temp.local]p1: (DR1004)
4532 // When [the injected-class-name] is used [...] as a template-argument for
4533 // a template template-parameter [...] it refers to the class template
4535 if (Arg.getArgument().getKind() == TemplateArgument::Type) {
4536 TemplateArgumentLoc ConvertedArg = convertTypeTemplateArgumentToTemplate(
4537 Arg.getTypeSourceInfo()->getTypeLoc());
4538 if (!ConvertedArg.getArgument().isNull())
4542 switch (Arg.getArgument().getKind()) {
4543 case TemplateArgument::Null:
4544 llvm_unreachable("Should never see a NULL template argument here");
4546 case TemplateArgument::Template:
4547 case TemplateArgument::TemplateExpansion:
4548 if (CheckTemplateArgument(TempParm, Arg, ArgumentPackIndex))
4551 Converted.push_back(Arg.getArgument());
4554 case TemplateArgument::Expression:
4555 case TemplateArgument::Type:
4556 // We have a template template parameter but the template
4557 // argument does not refer to a template.
4558 Diag(Arg.getLocation(), diag::err_template_arg_must_be_template)
4559 << getLangOpts().CPlusPlus11;
4562 case TemplateArgument::Declaration:
4563 llvm_unreachable("Declaration argument with template template parameter");
4564 case TemplateArgument::Integral:
4565 llvm_unreachable("Integral argument with template template parameter");
4566 case TemplateArgument::NullPtr:
4567 llvm_unreachable("Null pointer argument with template template parameter");
4569 case TemplateArgument::Pack:
4570 llvm_unreachable("Caller must expand template argument packs");
4576 /// \brief Diagnose an arity mismatch in the
4577 static bool diagnoseArityMismatch(Sema &S, TemplateDecl *Template,
4578 SourceLocation TemplateLoc,
4579 TemplateArgumentListInfo &TemplateArgs) {
4580 TemplateParameterList *Params = Template->getTemplateParameters();
4581 unsigned NumParams = Params->size();
4582 unsigned NumArgs = TemplateArgs.size();
4585 if (NumArgs > NumParams)
4586 Range = SourceRange(TemplateArgs[NumParams].getLocation(),
4587 TemplateArgs.getRAngleLoc());
4588 S.Diag(TemplateLoc, diag::err_template_arg_list_different_arity)
4589 << (NumArgs > NumParams)
4590 << (int)S.getTemplateNameKindForDiagnostics(TemplateName(Template))
4591 << Template << Range;
4592 S.Diag(Template->getLocation(), diag::note_template_decl_here)
4593 << Params->getSourceRange();
4597 /// \brief Check whether the template parameter is a pack expansion, and if so,
4598 /// determine the number of parameters produced by that expansion. For instance:
4601 /// template<typename ...Ts> struct A {
4602 /// template<Ts ...NTs, template<Ts> class ...TTs, typename ...Us> struct B;
4606 /// In \c A<int,int>::B, \c NTs and \c TTs have expanded pack size 2, and \c Us
4607 /// is not a pack expansion, so returns an empty Optional.
4608 static Optional<unsigned> getExpandedPackSize(NamedDecl *Param) {
4609 if (NonTypeTemplateParmDecl *NTTP
4610 = dyn_cast<NonTypeTemplateParmDecl>(Param)) {
4611 if (NTTP->isExpandedParameterPack())
4612 return NTTP->getNumExpansionTypes();
4615 if (TemplateTemplateParmDecl *TTP
4616 = dyn_cast<TemplateTemplateParmDecl>(Param)) {
4617 if (TTP->isExpandedParameterPack())
4618 return TTP->getNumExpansionTemplateParameters();
4624 /// Diagnose a missing template argument.
4625 template<typename TemplateParmDecl>
4626 static bool diagnoseMissingArgument(Sema &S, SourceLocation Loc,
4628 const TemplateParmDecl *D,
4629 TemplateArgumentListInfo &Args) {
4630 // Dig out the most recent declaration of the template parameter; there may be
4631 // declarations of the template that are more recent than TD.
4632 D = cast<TemplateParmDecl>(cast<TemplateDecl>(TD->getMostRecentDecl())
4633 ->getTemplateParameters()
4634 ->getParam(D->getIndex()));
4636 // If there's a default argument that's not visible, diagnose that we're
4637 // missing a module import.
4638 llvm::SmallVector<Module*, 8> Modules;
4639 if (D->hasDefaultArgument() && !S.hasVisibleDefaultArgument(D, &Modules)) {
4640 S.diagnoseMissingImport(Loc, cast<NamedDecl>(TD),
4641 D->getDefaultArgumentLoc(), Modules,
4642 Sema::MissingImportKind::DefaultArgument,
4647 // FIXME: If there's a more recent default argument that *is* visible,
4648 // diagnose that it was declared too late.
4650 return diagnoseArityMismatch(S, TD, Loc, Args);
4653 /// \brief Check that the given template argument list is well-formed
4654 /// for specializing the given template.
4655 bool Sema::CheckTemplateArgumentList(
4656 TemplateDecl *Template, SourceLocation TemplateLoc,
4657 TemplateArgumentListInfo &TemplateArgs, bool PartialTemplateArgs,
4658 SmallVectorImpl<TemplateArgument> &Converted,
4659 bool UpdateArgsWithConversions) {
4660 // Make a copy of the template arguments for processing. Only make the
4661 // changes at the end when successful in matching the arguments to the
4663 TemplateArgumentListInfo NewArgs = TemplateArgs;
4665 TemplateParameterList *Params = Template->getTemplateParameters();
4667 SourceLocation RAngleLoc = NewArgs.getRAngleLoc();
4669 // C++ [temp.arg]p1:
4670 // [...] The type and form of each template-argument specified in
4671 // a template-id shall match the type and form specified for the
4672 // corresponding parameter declared by the template in its
4673 // template-parameter-list.
4674 bool isTemplateTemplateParameter = isa<TemplateTemplateParmDecl>(Template);
4675 SmallVector<TemplateArgument, 2> ArgumentPack;
4676 unsigned ArgIdx = 0, NumArgs = NewArgs.size();
4677 LocalInstantiationScope InstScope(*this, true);
4678 for (TemplateParameterList::iterator Param = Params->begin(),
4679 ParamEnd = Params->end();
4680 Param != ParamEnd; /* increment in loop */) {
4681 // If we have an expanded parameter pack, make sure we don't have too
4683 if (Optional<unsigned> Expansions = getExpandedPackSize(*Param)) {
4684 if (*Expansions == ArgumentPack.size()) {
4685 // We're done with this parameter pack. Pack up its arguments and add
4686 // them to the list.
4687 Converted.push_back(
4688 TemplateArgument::CreatePackCopy(Context, ArgumentPack));
4689 ArgumentPack.clear();
4691 // This argument is assigned to the next parameter.
4694 } else if (ArgIdx == NumArgs && !PartialTemplateArgs) {
4695 // Not enough arguments for this parameter pack.
4696 Diag(TemplateLoc, diag::err_template_arg_list_different_arity)
4698 << (int)getTemplateNameKindForDiagnostics(TemplateName(Template))
4700 Diag(Template->getLocation(), diag::note_template_decl_here)
4701 << Params->getSourceRange();
4706 if (ArgIdx < NumArgs) {
4707 // Check the template argument we were given.
4708 if (CheckTemplateArgument(*Param, NewArgs[ArgIdx], Template,
4709 TemplateLoc, RAngleLoc,
4710 ArgumentPack.size(), Converted))
4713 bool PackExpansionIntoNonPack =
4714 NewArgs[ArgIdx].getArgument().isPackExpansion() &&
4715 (!(*Param)->isTemplateParameterPack() || getExpandedPackSize(*Param));
4716 if (PackExpansionIntoNonPack && isa<TypeAliasTemplateDecl>(Template)) {
4717 // Core issue 1430: we have a pack expansion as an argument to an
4718 // alias template, and it's not part of a parameter pack. This
4719 // can't be canonicalized, so reject it now.
4720 Diag(NewArgs[ArgIdx].getLocation(),
4721 diag::err_alias_template_expansion_into_fixed_list)
4722 << NewArgs[ArgIdx].getSourceRange();
4723 Diag((*Param)->getLocation(), diag::note_template_param_here);
4727 // We're now done with this argument.
4730 if ((*Param)->isTemplateParameterPack()) {
4731 // The template parameter was a template parameter pack, so take the
4732 // deduced argument and place it on the argument pack. Note that we
4733 // stay on the same template parameter so that we can deduce more
4735 ArgumentPack.push_back(Converted.pop_back_val());
4737 // Move to the next template parameter.
4741 // If we just saw a pack expansion into a non-pack, then directly convert
4742 // the remaining arguments, because we don't know what parameters they'll
4744 if (PackExpansionIntoNonPack) {
4745 if (!ArgumentPack.empty()) {
4746 // If we were part way through filling in an expanded parameter pack,
4747 // fall back to just producing individual arguments.
4748 Converted.insert(Converted.end(),
4749 ArgumentPack.begin(), ArgumentPack.end());
4750 ArgumentPack.clear();
4753 while (ArgIdx < NumArgs) {
4754 Converted.push_back(NewArgs[ArgIdx].getArgument());
4764 // If we're checking a partial template argument list, we're done.
4765 if (PartialTemplateArgs) {
4766 if ((*Param)->isTemplateParameterPack() && !ArgumentPack.empty())
4767 Converted.push_back(
4768 TemplateArgument::CreatePackCopy(Context, ArgumentPack));
4773 // If we have a template parameter pack with no more corresponding
4774 // arguments, just break out now and we'll fill in the argument pack below.
4775 if ((*Param)->isTemplateParameterPack()) {
4776 assert(!getExpandedPackSize(*Param) &&
4777 "Should have dealt with this already");
4779 // A non-expanded parameter pack before the end of the parameter list
4780 // only occurs for an ill-formed template parameter list, unless we've
4781 // got a partial argument list for a function template, so just bail out.
4782 if (Param + 1 != ParamEnd)
4785 Converted.push_back(
4786 TemplateArgument::CreatePackCopy(Context, ArgumentPack));
4787 ArgumentPack.clear();
4793 // Check whether we have a default argument.
4794 TemplateArgumentLoc Arg;
4796 // Retrieve the default template argument from the template
4797 // parameter. For each kind of template parameter, we substitute the
4798 // template arguments provided thus far and any "outer" template arguments
4799 // (when the template parameter was part of a nested template) into
4800 // the default argument.
4801 if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(*Param)) {
4802 if (!hasVisibleDefaultArgument(TTP))
4803 return diagnoseMissingArgument(*this, TemplateLoc, Template, TTP,
4806 TypeSourceInfo *ArgType = SubstDefaultTemplateArgument(*this,
4815 Arg = TemplateArgumentLoc(TemplateArgument(ArgType->getType()),
4817 } else if (NonTypeTemplateParmDecl *NTTP
4818 = dyn_cast<NonTypeTemplateParmDecl>(*Param)) {
4819 if (!hasVisibleDefaultArgument(NTTP))
4820 return diagnoseMissingArgument(*this, TemplateLoc, Template, NTTP,
4823 ExprResult E = SubstDefaultTemplateArgument(*this, Template,
4831 Expr *Ex = E.getAs<Expr>();
4832 Arg = TemplateArgumentLoc(TemplateArgument(Ex), Ex);
4834 TemplateTemplateParmDecl *TempParm
4835 = cast<TemplateTemplateParmDecl>(*Param);
4837 if (!hasVisibleDefaultArgument(TempParm))
4838 return diagnoseMissingArgument(*this, TemplateLoc, Template, TempParm,
4841 NestedNameSpecifierLoc QualifierLoc;
4842 TemplateName Name = SubstDefaultTemplateArgument(*this, Template,
4851 Arg = TemplateArgumentLoc(TemplateArgument(Name), QualifierLoc,
4852 TempParm->getDefaultArgument().getTemplateNameLoc());
4855 // Introduce an instantiation record that describes where we are using
4856 // the default template argument. We're not actually instantiating a
4857 // template here, we just create this object to put a note into the
4859 InstantiatingTemplate Inst(*this, RAngleLoc, Template, *Param, Converted,
4860 SourceRange(TemplateLoc, RAngleLoc));
4861 if (Inst.isInvalid())
4864 // Check the default template argument.
4865 if (CheckTemplateArgument(*Param, Arg, Template, TemplateLoc,
4866 RAngleLoc, 0, Converted))
4869 // Core issue 150 (assumed resolution): if this is a template template
4870 // parameter, keep track of the default template arguments from the
4871 // template definition.
4872 if (isTemplateTemplateParameter)
4873 NewArgs.addArgument(Arg);
4875 // Move to the next template parameter and argument.
4880 // If we're performing a partial argument substitution, allow any trailing
4881 // pack expansions; they might be empty. This can happen even if
4882 // PartialTemplateArgs is false (the list of arguments is complete but
4883 // still dependent).
4884 if (ArgIdx < NumArgs && CurrentInstantiationScope &&
4885 CurrentInstantiationScope->getPartiallySubstitutedPack()) {
4886 while (ArgIdx < NumArgs && NewArgs[ArgIdx].getArgument().isPackExpansion())
4887 Converted.push_back(NewArgs[ArgIdx++].getArgument());
4890 // If we have any leftover arguments, then there were too many arguments.
4891 // Complain and fail.
4892 if (ArgIdx < NumArgs)
4893 return diagnoseArityMismatch(*this, Template, TemplateLoc, NewArgs);
4895 // No problems found with the new argument list, propagate changes back
4897 if (UpdateArgsWithConversions)
4898 TemplateArgs = std::move(NewArgs);
4904 class UnnamedLocalNoLinkageFinder
4905 : public TypeVisitor<UnnamedLocalNoLinkageFinder, bool>
4910 typedef TypeVisitor<UnnamedLocalNoLinkageFinder, bool> inherited;
4913 UnnamedLocalNoLinkageFinder(Sema &S, SourceRange SR) : S(S), SR(SR) { }
4915 bool Visit(QualType T) {
4916 return T.isNull() ? false : inherited::Visit(T.getTypePtr());
4919 #define TYPE(Class, Parent) \
4920 bool Visit##Class##Type(const Class##Type *);
4921 #define ABSTRACT_TYPE(Class, Parent) \
4922 bool Visit##Class##Type(const Class##Type *) { return false; }
4923 #define NON_CANONICAL_TYPE(Class, Parent) \
4924 bool Visit##Class##Type(const Class##Type *) { return false; }
4925 #include "clang/AST/TypeNodes.def"
4927 bool VisitTagDecl(const TagDecl *Tag);
4928 bool VisitNestedNameSpecifier(NestedNameSpecifier *NNS);
4930 } // end anonymous namespace
4932 bool UnnamedLocalNoLinkageFinder::VisitBuiltinType(const BuiltinType*) {
4936 bool UnnamedLocalNoLinkageFinder::VisitComplexType(const ComplexType* T) {
4937 return Visit(T->getElementType());
4940 bool UnnamedLocalNoLinkageFinder::VisitPointerType(const PointerType* T) {
4941 return Visit(T->getPointeeType());
4944 bool UnnamedLocalNoLinkageFinder::VisitBlockPointerType(
4945 const BlockPointerType* T) {
4946 return Visit(T->getPointeeType());
4949 bool UnnamedLocalNoLinkageFinder::VisitLValueReferenceType(
4950 const LValueReferenceType* T) {
4951 return Visit(T->getPointeeType());
4954 bool UnnamedLocalNoLinkageFinder::VisitRValueReferenceType(
4955 const RValueReferenceType* T) {
4956 return Visit(T->getPointeeType());
4959 bool UnnamedLocalNoLinkageFinder::VisitMemberPointerType(
4960 const MemberPointerType* T) {
4961 return Visit(T->getPointeeType()) || Visit(QualType(T->getClass(), 0));
4964 bool UnnamedLocalNoLinkageFinder::VisitConstantArrayType(
4965 const ConstantArrayType* T) {
4966 return Visit(T->getElementType());
4969 bool UnnamedLocalNoLinkageFinder::VisitIncompleteArrayType(
4970 const IncompleteArrayType* T) {
4971 return Visit(T->getElementType());
4974 bool UnnamedLocalNoLinkageFinder::VisitVariableArrayType(
4975 const VariableArrayType* T) {
4976 return Visit(T->getElementType());
4979 bool UnnamedLocalNoLinkageFinder::VisitDependentSizedArrayType(
4980 const DependentSizedArrayType* T) {
4981 return Visit(T->getElementType());
4984 bool UnnamedLocalNoLinkageFinder::VisitDependentSizedExtVectorType(
4985 const DependentSizedExtVectorType* T) {
4986 return Visit(T->getElementType());
4989 bool UnnamedLocalNoLinkageFinder::VisitVectorType(const VectorType* T) {
4990 return Visit(T->getElementType());
4993 bool UnnamedLocalNoLinkageFinder::VisitExtVectorType(const ExtVectorType* T) {
4994 return Visit(T->getElementType());
4997 bool UnnamedLocalNoLinkageFinder::VisitFunctionProtoType(
4998 const FunctionProtoType* T) {
4999 for (const auto &A : T->param_types()) {
5004 return Visit(T->getReturnType());
5007 bool UnnamedLocalNoLinkageFinder::VisitFunctionNoProtoType(
5008 const FunctionNoProtoType* T) {
5009 return Visit(T->getReturnType());
5012 bool UnnamedLocalNoLinkageFinder::VisitUnresolvedUsingType(
5013 const UnresolvedUsingType*) {
5017 bool UnnamedLocalNoLinkageFinder::VisitTypeOfExprType(const TypeOfExprType*) {
5021 bool UnnamedLocalNoLinkageFinder::VisitTypeOfType(const TypeOfType* T) {
5022 return Visit(T->getUnderlyingType());
5025 bool UnnamedLocalNoLinkageFinder::VisitDecltypeType(const DecltypeType*) {
5029 bool UnnamedLocalNoLinkageFinder::VisitUnaryTransformType(
5030 const UnaryTransformType*) {
5034 bool UnnamedLocalNoLinkageFinder::VisitAutoType(const AutoType *T) {
5035 return Visit(T->getDeducedType());
5038 bool UnnamedLocalNoLinkageFinder::VisitDeducedTemplateSpecializationType(
5039 const DeducedTemplateSpecializationType *T) {
5040 return Visit(T->getDeducedType());
5043 bool UnnamedLocalNoLinkageFinder::VisitRecordType(const RecordType* T) {
5044 return VisitTagDecl(T->getDecl());
5047 bool UnnamedLocalNoLinkageFinder::VisitEnumType(const EnumType* T) {
5048 return VisitTagDecl(T->getDecl());
5051 bool UnnamedLocalNoLinkageFinder::VisitTemplateTypeParmType(
5052 const TemplateTypeParmType*) {
5056 bool UnnamedLocalNoLinkageFinder::VisitSubstTemplateTypeParmPackType(
5057 const SubstTemplateTypeParmPackType *) {
5061 bool UnnamedLocalNoLinkageFinder::VisitTemplateSpecializationType(
5062 const TemplateSpecializationType*) {
5066 bool UnnamedLocalNoLinkageFinder::VisitInjectedClassNameType(
5067 const InjectedClassNameType* T) {
5068 return VisitTagDecl(T->getDecl());
5071 bool UnnamedLocalNoLinkageFinder::VisitDependentNameType(
5072 const DependentNameType* T) {
5073 return VisitNestedNameSpecifier(T->getQualifier());
5076 bool UnnamedLocalNoLinkageFinder::VisitDependentTemplateSpecializationType(
5077 const DependentTemplateSpecializationType* T) {
5078 return VisitNestedNameSpecifier(T->getQualifier());
5081 bool UnnamedLocalNoLinkageFinder::VisitPackExpansionType(
5082 const PackExpansionType* T) {
5083 return Visit(T->getPattern());
5086 bool UnnamedLocalNoLinkageFinder::VisitObjCObjectType(const ObjCObjectType *) {
5090 bool UnnamedLocalNoLinkageFinder::VisitObjCInterfaceType(
5091 const ObjCInterfaceType *) {
5095 bool UnnamedLocalNoLinkageFinder::VisitObjCObjectPointerType(
5096 const ObjCObjectPointerType *) {
5100 bool UnnamedLocalNoLinkageFinder::VisitAtomicType(const AtomicType* T) {
5101 return Visit(T->getValueType());
5104 bool UnnamedLocalNoLinkageFinder::VisitPipeType(const PipeType* T) {
5108 bool UnnamedLocalNoLinkageFinder::VisitTagDecl(const TagDecl *Tag) {
5109 if (Tag->getDeclContext()->isFunctionOrMethod()) {
5110 S.Diag(SR.getBegin(),
5111 S.getLangOpts().CPlusPlus11 ?
5112 diag::warn_cxx98_compat_template_arg_local_type :
5113 diag::ext_template_arg_local_type)
5114 << S.Context.getTypeDeclType(Tag) << SR;
5118 if (!Tag->hasNameForLinkage()) {
5119 S.Diag(SR.getBegin(),
5120 S.getLangOpts().CPlusPlus11 ?
5121 diag::warn_cxx98_compat_template_arg_unnamed_type :
5122 diag::ext_template_arg_unnamed_type) << SR;
5123 S.Diag(Tag->getLocation(), diag::note_template_unnamed_type_here);
5130 bool UnnamedLocalNoLinkageFinder::VisitNestedNameSpecifier(
5131 NestedNameSpecifier *NNS) {
5132 if (NNS->getPrefix() && VisitNestedNameSpecifier(NNS->getPrefix()))
5135 switch (NNS->getKind()) {
5136 case NestedNameSpecifier::Identifier:
5137 case NestedNameSpecifier::Namespace:
5138 case NestedNameSpecifier::NamespaceAlias:
5139 case NestedNameSpecifier::Global:
5140 case NestedNameSpecifier::Super:
5143 case NestedNameSpecifier::TypeSpec:
5144 case NestedNameSpecifier::TypeSpecWithTemplate:
5145 return Visit(QualType(NNS->getAsType(), 0));
5147 llvm_unreachable("Invalid NestedNameSpecifier::Kind!");
5150 /// \brief Check a template argument against its corresponding
5151 /// template type parameter.
5153 /// This routine implements the semantics of C++ [temp.arg.type]. It
5154 /// returns true if an error occurred, and false otherwise.
5155 bool Sema::CheckTemplateArgument(TemplateTypeParmDecl *Param,
5156 TypeSourceInfo *ArgInfo) {
5157 assert(ArgInfo && "invalid TypeSourceInfo");
5158 QualType Arg = ArgInfo->getType();
5159 SourceRange SR = ArgInfo->getTypeLoc().getSourceRange();
5161 if (Arg->isVariablyModifiedType()) {
5162 return Diag(SR.getBegin(), diag::err_variably_modified_template_arg) << Arg;
5163 } else if (Context.hasSameUnqualifiedType(Arg, Context.OverloadTy)) {
5164 return Diag(SR.getBegin(), diag::err_template_arg_overload_type) << SR;
5167 // C++03 [temp.arg.type]p2:
5168 // A local type, a type with no linkage, an unnamed type or a type
5169 // compounded from any of these types shall not be used as a
5170 // template-argument for a template type-parameter.
5172 // C++11 allows these, and even in C++03 we allow them as an extension with
5174 if (LangOpts.CPlusPlus11 || Arg->hasUnnamedOrLocalType()) {
5175 UnnamedLocalNoLinkageFinder Finder(*this, SR);
5176 (void)Finder.Visit(Context.getCanonicalType(Arg));
5182 enum NullPointerValueKind {
5188 /// \brief Determine whether the given template argument is a null pointer
5189 /// value of the appropriate type.
5190 static NullPointerValueKind
5191 isNullPointerValueTemplateArgument(Sema &S, NonTypeTemplateParmDecl *Param,
5192 QualType ParamType, Expr *Arg) {
5193 if (Arg->isValueDependent() || Arg->isTypeDependent())
5194 return NPV_NotNullPointer;
5196 if (!S.isCompleteType(Arg->getExprLoc(), ParamType))
5198 "Incomplete parameter type in isNullPointerValueTemplateArgument!");
5200 if (!S.getLangOpts().CPlusPlus11)
5201 return NPV_NotNullPointer;
5203 // Determine whether we have a constant expression.
5204 ExprResult ArgRV = S.DefaultFunctionArrayConversion(Arg);
5205 if (ArgRV.isInvalid())
5209 Expr::EvalResult EvalResult;
5210 SmallVector<PartialDiagnosticAt, 8> Notes;
5211 EvalResult.Diag = &Notes;
5212 if (!Arg->EvaluateAsRValue(EvalResult, S.Context) ||
5213 EvalResult.HasSideEffects) {
5214 SourceLocation DiagLoc = Arg->getExprLoc();
5216 // If our only note is the usual "invalid subexpression" note, just point
5217 // the caret at its location rather than producing an essentially
5219 if (Notes.size() == 1 && Notes[0].second.getDiagID() ==
5220 diag::note_invalid_subexpr_in_const_expr) {
5221 DiagLoc = Notes[0].first;
5225 S.Diag(DiagLoc, diag::err_template_arg_not_address_constant)
5226 << Arg->getType() << Arg->getSourceRange();
5227 for (unsigned I = 0, N = Notes.size(); I != N; ++I)
5228 S.Diag(Notes[I].first, Notes[I].second);
5230 S.Diag(Param->getLocation(), diag::note_template_param_here);
5234 // C++11 [temp.arg.nontype]p1:
5235 // - an address constant expression of type std::nullptr_t
5236 if (Arg->getType()->isNullPtrType())
5237 return NPV_NullPointer;
5239 // - a constant expression that evaluates to a null pointer value (4.10); or
5240 // - a constant expression that evaluates to a null member pointer value
5242 if ((EvalResult.Val.isLValue() && !EvalResult.Val.getLValueBase()) ||
5243 (EvalResult.Val.isMemberPointer() &&
5244 !EvalResult.Val.getMemberPointerDecl())) {
5245 // If our expression has an appropriate type, we've succeeded.
5246 bool ObjCLifetimeConversion;
5247 if (S.Context.hasSameUnqualifiedType(Arg->getType(), ParamType) ||
5248 S.IsQualificationConversion(Arg->getType(), ParamType, false,
5249 ObjCLifetimeConversion))
5250 return NPV_NullPointer;
5252 // The types didn't match, but we know we got a null pointer; complain,
5253 // then recover as if the types were correct.
5254 S.Diag(Arg->getExprLoc(), diag::err_template_arg_wrongtype_null_constant)
5255 << Arg->getType() << ParamType << Arg->getSourceRange();
5256 S.Diag(Param->getLocation(), diag::note_template_param_here);
5257 return NPV_NullPointer;
5260 // If we don't have a null pointer value, but we do have a NULL pointer
5261 // constant, suggest a cast to the appropriate type.
5262 if (Arg->isNullPointerConstant(S.Context, Expr::NPC_NeverValueDependent)) {
5263 std::string Code = "static_cast<" + ParamType.getAsString() + ">(";
5264 S.Diag(Arg->getExprLoc(), diag::err_template_arg_untyped_null_constant)
5265 << ParamType << FixItHint::CreateInsertion(Arg->getLocStart(), Code)
5266 << FixItHint::CreateInsertion(S.getLocForEndOfToken(Arg->getLocEnd()),
5268 S.Diag(Param->getLocation(), diag::note_template_param_here);
5269 return NPV_NullPointer;
5272 // FIXME: If we ever want to support general, address-constant expressions
5273 // as non-type template arguments, we should return the ExprResult here to
5274 // be interpreted by the caller.
5275 return NPV_NotNullPointer;
5278 /// \brief Checks whether the given template argument is compatible with its
5279 /// template parameter.
5280 static bool CheckTemplateArgumentIsCompatibleWithParameter(
5281 Sema &S, NonTypeTemplateParmDecl *Param, QualType ParamType, Expr *ArgIn,
5282 Expr *Arg, QualType ArgType) {
5283 bool ObjCLifetimeConversion;
5284 if (ParamType->isPointerType() &&
5285 !ParamType->getAs<PointerType>()->getPointeeType()->isFunctionType() &&
5286 S.IsQualificationConversion(ArgType, ParamType, false,
5287 ObjCLifetimeConversion)) {
5288 // For pointer-to-object types, qualification conversions are
5291 if (const ReferenceType *ParamRef = ParamType->getAs<ReferenceType>()) {
5292 if (!ParamRef->getPointeeType()->isFunctionType()) {
5293 // C++ [temp.arg.nontype]p5b3:
5294 // For a non-type template-parameter of type reference to
5295 // object, no conversions apply. The type referred to by the
5296 // reference may be more cv-qualified than the (otherwise
5297 // identical) type of the template- argument. The
5298 // template-parameter is bound directly to the
5299 // template-argument, which shall be an lvalue.
5301 // FIXME: Other qualifiers?
5302 unsigned ParamQuals = ParamRef->getPointeeType().getCVRQualifiers();
5303 unsigned ArgQuals = ArgType.getCVRQualifiers();
5305 if ((ParamQuals | ArgQuals) != ParamQuals) {
5306 S.Diag(Arg->getLocStart(),
5307 diag::err_template_arg_ref_bind_ignores_quals)
5308 << ParamType << Arg->getType() << Arg->getSourceRange();
5309 S.Diag(Param->getLocation(), diag::note_template_param_here);
5315 // At this point, the template argument refers to an object or
5316 // function with external linkage. We now need to check whether the
5317 // argument and parameter types are compatible.
5318 if (!S.Context.hasSameUnqualifiedType(ArgType,
5319 ParamType.getNonReferenceType())) {
5320 // We can't perform this conversion or binding.
5321 if (ParamType->isReferenceType())
5322 S.Diag(Arg->getLocStart(), diag::err_template_arg_no_ref_bind)
5323 << ParamType << ArgIn->getType() << Arg->getSourceRange();
5325 S.Diag(Arg->getLocStart(), diag::err_template_arg_not_convertible)
5326 << ArgIn->getType() << ParamType << Arg->getSourceRange();
5327 S.Diag(Param->getLocation(), diag::note_template_param_here);
5335 /// \brief Checks whether the given template argument is the address
5336 /// of an object or function according to C++ [temp.arg.nontype]p1.
5338 CheckTemplateArgumentAddressOfObjectOrFunction(Sema &S,
5339 NonTypeTemplateParmDecl *Param,
5342 TemplateArgument &Converted) {
5343 bool Invalid = false;
5345 QualType ArgType = Arg->getType();
5347 bool AddressTaken = false;
5348 SourceLocation AddrOpLoc;
5349 if (S.getLangOpts().MicrosoftExt) {
5350 // Microsoft Visual C++ strips all casts, allows an arbitrary number of
5351 // dereference and address-of operators.
5352 Arg = Arg->IgnoreParenCasts();
5354 bool ExtWarnMSTemplateArg = false;
5355 UnaryOperatorKind FirstOpKind;
5356 SourceLocation FirstOpLoc;
5357 while (UnaryOperator *UnOp = dyn_cast<UnaryOperator>(Arg)) {
5358 UnaryOperatorKind UnOpKind = UnOp->getOpcode();
5359 if (UnOpKind == UO_Deref)
5360 ExtWarnMSTemplateArg = true;
5361 if (UnOpKind == UO_AddrOf || UnOpKind == UO_Deref) {
5362 Arg = UnOp->getSubExpr()->IgnoreParenCasts();
5363 if (!AddrOpLoc.isValid()) {
5364 FirstOpKind = UnOpKind;
5365 FirstOpLoc = UnOp->getOperatorLoc();
5370 if (FirstOpLoc.isValid()) {
5371 if (ExtWarnMSTemplateArg)
5372 S.Diag(ArgIn->getLocStart(), diag::ext_ms_deref_template_argument)
5373 << ArgIn->getSourceRange();
5375 if (FirstOpKind == UO_AddrOf)
5376 AddressTaken = true;
5377 else if (Arg->getType()->isPointerType()) {
5378 // We cannot let pointers get dereferenced here, that is obviously not a
5379 // constant expression.
5380 assert(FirstOpKind == UO_Deref);
5381 S.Diag(Arg->getLocStart(), diag::err_template_arg_not_decl_ref)
5382 << Arg->getSourceRange();
5386 // See through any implicit casts we added to fix the type.
5387 Arg = Arg->IgnoreImpCasts();
5389 // C++ [temp.arg.nontype]p1:
5391 // A template-argument for a non-type, non-template
5392 // template-parameter shall be one of: [...]
5394 // -- the address of an object or function with external
5395 // linkage, including function templates and function
5396 // template-ids but excluding non-static class members,
5397 // expressed as & id-expression where the & is optional if
5398 // the name refers to a function or array, or if the
5399 // corresponding template-parameter is a reference; or
5401 // In C++98/03 mode, give an extension warning on any extra parentheses.
5402 // See http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#773
5403 bool ExtraParens = false;
5404 while (ParenExpr *Parens = dyn_cast<ParenExpr>(Arg)) {
5405 if (!Invalid && !ExtraParens) {
5406 S.Diag(Arg->getLocStart(),
5407 S.getLangOpts().CPlusPlus11
5408 ? diag::warn_cxx98_compat_template_arg_extra_parens
5409 : diag::ext_template_arg_extra_parens)
5410 << Arg->getSourceRange();
5414 Arg = Parens->getSubExpr();
5417 while (SubstNonTypeTemplateParmExpr *subst =
5418 dyn_cast<SubstNonTypeTemplateParmExpr>(Arg))
5419 Arg = subst->getReplacement()->IgnoreImpCasts();
5421 if (UnaryOperator *UnOp = dyn_cast<UnaryOperator>(Arg)) {
5422 if (UnOp->getOpcode() == UO_AddrOf) {
5423 Arg = UnOp->getSubExpr();
5424 AddressTaken = true;
5425 AddrOpLoc = UnOp->getOperatorLoc();
5429 while (SubstNonTypeTemplateParmExpr *subst =
5430 dyn_cast<SubstNonTypeTemplateParmExpr>(Arg))
5431 Arg = subst->getReplacement()->IgnoreImpCasts();
5434 DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Arg);
5435 ValueDecl *Entity = DRE ? DRE->getDecl() : nullptr;
5437 // If our parameter has pointer type, check for a null template value.
5438 if (ParamType->isPointerType() || ParamType->isNullPtrType()) {
5439 NullPointerValueKind NPV;
5440 // dllimport'd entities aren't constant but are available inside of template
5442 if (Entity && Entity->hasAttr<DLLImportAttr>())
5443 NPV = NPV_NotNullPointer;
5445 NPV = isNullPointerValueTemplateArgument(S, Param, ParamType, ArgIn);
5447 case NPV_NullPointer:
5448 S.Diag(Arg->getExprLoc(), diag::warn_cxx98_compat_template_arg_null);
5449 Converted = TemplateArgument(S.Context.getCanonicalType(ParamType),
5450 /*isNullPtr=*/true);
5456 case NPV_NotNullPointer:
5461 // Stop checking the precise nature of the argument if it is value dependent,
5462 // it should be checked when instantiated.
5463 if (Arg->isValueDependent()) {
5464 Converted = TemplateArgument(ArgIn);
5468 if (isa<CXXUuidofExpr>(Arg)) {
5469 if (CheckTemplateArgumentIsCompatibleWithParameter(S, Param, ParamType,
5470 ArgIn, Arg, ArgType))
5473 Converted = TemplateArgument(ArgIn);
5478 S.Diag(Arg->getLocStart(), diag::err_template_arg_not_decl_ref)
5479 << Arg->getSourceRange();
5480 S.Diag(Param->getLocation(), diag::note_template_param_here);
5484 // Cannot refer to non-static data members
5485 if (isa<FieldDecl>(Entity) || isa<IndirectFieldDecl>(Entity)) {
5486 S.Diag(Arg->getLocStart(), diag::err_template_arg_field)
5487 << Entity << Arg->getSourceRange();
5488 S.Diag(Param->getLocation(), diag::note_template_param_here);
5492 // Cannot refer to non-static member functions
5493 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Entity)) {
5494 if (!Method->isStatic()) {
5495 S.Diag(Arg->getLocStart(), diag::err_template_arg_method)
5496 << Method << Arg->getSourceRange();
5497 S.Diag(Param->getLocation(), diag::note_template_param_here);
5502 FunctionDecl *Func = dyn_cast<FunctionDecl>(Entity);
5503 VarDecl *Var = dyn_cast<VarDecl>(Entity);
5505 // A non-type template argument must refer to an object or function.
5506 if (!Func && !Var) {
5507 // We found something, but we don't know specifically what it is.
5508 S.Diag(Arg->getLocStart(), diag::err_template_arg_not_object_or_func)
5509 << Arg->getSourceRange();
5510 S.Diag(DRE->getDecl()->getLocation(), diag::note_template_arg_refers_here);
5514 // Address / reference template args must have external linkage in C++98.
5515 if (Entity->getFormalLinkage() == InternalLinkage) {
5516 S.Diag(Arg->getLocStart(), S.getLangOpts().CPlusPlus11 ?
5517 diag::warn_cxx98_compat_template_arg_object_internal :
5518 diag::ext_template_arg_object_internal)
5519 << !Func << Entity << Arg->getSourceRange();
5520 S.Diag(Entity->getLocation(), diag::note_template_arg_internal_object)
5522 } else if (!Entity->hasLinkage()) {
5523 S.Diag(Arg->getLocStart(), diag::err_template_arg_object_no_linkage)
5524 << !Func << Entity << Arg->getSourceRange();
5525 S.Diag(Entity->getLocation(), diag::note_template_arg_internal_object)
5531 // If the template parameter has pointer type, the function decays.
5532 if (ParamType->isPointerType() && !AddressTaken)
5533 ArgType = S.Context.getPointerType(Func->getType());
5534 else if (AddressTaken && ParamType->isReferenceType()) {
5535 // If we originally had an address-of operator, but the
5536 // parameter has reference type, complain and (if things look
5537 // like they will work) drop the address-of operator.
5538 if (!S.Context.hasSameUnqualifiedType(Func->getType(),
5539 ParamType.getNonReferenceType())) {
5540 S.Diag(AddrOpLoc, diag::err_template_arg_address_of_non_pointer)
5542 S.Diag(Param->getLocation(), diag::note_template_param_here);
5546 S.Diag(AddrOpLoc, diag::err_template_arg_address_of_non_pointer)
5548 << FixItHint::CreateRemoval(AddrOpLoc);
5549 S.Diag(Param->getLocation(), diag::note_template_param_here);
5551 ArgType = Func->getType();
5554 // A value of reference type is not an object.
5555 if (Var->getType()->isReferenceType()) {
5556 S.Diag(Arg->getLocStart(),
5557 diag::err_template_arg_reference_var)
5558 << Var->getType() << Arg->getSourceRange();
5559 S.Diag(Param->getLocation(), diag::note_template_param_here);
5563 // A template argument must have static storage duration.
5564 if (Var->getTLSKind()) {
5565 S.Diag(Arg->getLocStart(), diag::err_template_arg_thread_local)
5566 << Arg->getSourceRange();
5567 S.Diag(Var->getLocation(), diag::note_template_arg_refers_here);
5571 // If the template parameter has pointer type, we must have taken
5572 // the address of this object.
5573 if (ParamType->isReferenceType()) {
5575 // If we originally had an address-of operator, but the
5576 // parameter has reference type, complain and (if things look
5577 // like they will work) drop the address-of operator.
5578 if (!S.Context.hasSameUnqualifiedType(Var->getType(),
5579 ParamType.getNonReferenceType())) {
5580 S.Diag(AddrOpLoc, diag::err_template_arg_address_of_non_pointer)
5582 S.Diag(Param->getLocation(), diag::note_template_param_here);
5586 S.Diag(AddrOpLoc, diag::err_template_arg_address_of_non_pointer)
5588 << FixItHint::CreateRemoval(AddrOpLoc);
5589 S.Diag(Param->getLocation(), diag::note_template_param_here);
5591 ArgType = Var->getType();
5593 } else if (!AddressTaken && ParamType->isPointerType()) {
5594 if (Var->getType()->isArrayType()) {
5595 // Array-to-pointer decay.
5596 ArgType = S.Context.getArrayDecayedType(Var->getType());
5598 // If the template parameter has pointer type but the address of
5599 // this object was not taken, complain and (possibly) recover by
5600 // taking the address of the entity.
5601 ArgType = S.Context.getPointerType(Var->getType());
5602 if (!S.Context.hasSameUnqualifiedType(ArgType, ParamType)) {
5603 S.Diag(Arg->getLocStart(), diag::err_template_arg_not_address_of)
5605 S.Diag(Param->getLocation(), diag::note_template_param_here);
5609 S.Diag(Arg->getLocStart(), diag::err_template_arg_not_address_of)
5611 << FixItHint::CreateInsertion(Arg->getLocStart(), "&");
5613 S.Diag(Param->getLocation(), diag::note_template_param_here);
5618 if (CheckTemplateArgumentIsCompatibleWithParameter(S, Param, ParamType, ArgIn,
5622 // Create the template argument.
5624 TemplateArgument(cast<ValueDecl>(Entity->getCanonicalDecl()), ParamType);
5625 S.MarkAnyDeclReferenced(Arg->getLocStart(), Entity, false);
5629 /// \brief Checks whether the given template argument is a pointer to
5630 /// member constant according to C++ [temp.arg.nontype]p1.
5631 static bool CheckTemplateArgumentPointerToMember(Sema &S,
5632 NonTypeTemplateParmDecl *Param,
5635 TemplateArgument &Converted) {
5636 bool Invalid = false;
5638 // Check for a null pointer value.
5639 Expr *Arg = ResultArg;
5640 switch (isNullPointerValueTemplateArgument(S, Param, ParamType, Arg)) {
5643 case NPV_NullPointer:
5644 S.Diag(Arg->getExprLoc(), diag::warn_cxx98_compat_template_arg_null);
5645 Converted = TemplateArgument(S.Context.getCanonicalType(ParamType),
5648 case NPV_NotNullPointer:
5652 bool ObjCLifetimeConversion;
5653 if (S.IsQualificationConversion(Arg->getType(),
5654 ParamType.getNonReferenceType(),
5655 false, ObjCLifetimeConversion)) {
5656 Arg = S.ImpCastExprToType(Arg, ParamType, CK_NoOp,
5657 Arg->getValueKind()).get();
5659 } else if (!S.Context.hasSameUnqualifiedType(Arg->getType(),
5660 ParamType.getNonReferenceType())) {
5661 // We can't perform this conversion.
5662 S.Diag(Arg->getLocStart(), diag::err_template_arg_not_convertible)
5663 << Arg->getType() << ParamType << Arg->getSourceRange();
5664 S.Diag(Param->getLocation(), diag::note_template_param_here);
5668 // See through any implicit casts we added to fix the type.
5669 while (ImplicitCastExpr *Cast = dyn_cast<ImplicitCastExpr>(Arg))
5670 Arg = Cast->getSubExpr();
5672 // C++ [temp.arg.nontype]p1:
5674 // A template-argument for a non-type, non-template
5675 // template-parameter shall be one of: [...]
5677 // -- a pointer to member expressed as described in 5.3.1.
5678 DeclRefExpr *DRE = nullptr;
5680 // In C++98/03 mode, give an extension warning on any extra parentheses.
5681 // See http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#773
5682 bool ExtraParens = false;
5683 while (ParenExpr *Parens = dyn_cast<ParenExpr>(Arg)) {
5684 if (!Invalid && !ExtraParens) {
5685 S.Diag(Arg->getLocStart(),
5686 S.getLangOpts().CPlusPlus11 ?
5687 diag::warn_cxx98_compat_template_arg_extra_parens :
5688 diag::ext_template_arg_extra_parens)
5689 << Arg->getSourceRange();
5693 Arg = Parens->getSubExpr();
5696 while (SubstNonTypeTemplateParmExpr *subst =
5697 dyn_cast<SubstNonTypeTemplateParmExpr>(Arg))
5698 Arg = subst->getReplacement()->IgnoreImpCasts();
5700 // A pointer-to-member constant written &Class::member.
5701 if (UnaryOperator *UnOp = dyn_cast<UnaryOperator>(Arg)) {
5702 if (UnOp->getOpcode() == UO_AddrOf) {
5703 DRE = dyn_cast<DeclRefExpr>(UnOp->getSubExpr());
5704 if (DRE && !DRE->getQualifier())
5708 // A constant of pointer-to-member type.
5709 else if ((DRE = dyn_cast<DeclRefExpr>(Arg))) {
5710 if (ValueDecl *VD = dyn_cast<ValueDecl>(DRE->getDecl())) {
5711 if (VD->getType()->isMemberPointerType()) {
5712 if (isa<NonTypeTemplateParmDecl>(VD)) {
5713 if (Arg->isTypeDependent() || Arg->isValueDependent()) {
5714 Converted = TemplateArgument(Arg);
5716 VD = cast<ValueDecl>(VD->getCanonicalDecl());
5717 Converted = TemplateArgument(VD, ParamType);
5728 return S.Diag(Arg->getLocStart(),
5729 diag::err_template_arg_not_pointer_to_member_form)
5730 << Arg->getSourceRange();
5732 if (isa<FieldDecl>(DRE->getDecl()) ||
5733 isa<IndirectFieldDecl>(DRE->getDecl()) ||
5734 isa<CXXMethodDecl>(DRE->getDecl())) {
5735 assert((isa<FieldDecl>(DRE->getDecl()) ||
5736 isa<IndirectFieldDecl>(DRE->getDecl()) ||
5737 !cast<CXXMethodDecl>(DRE->getDecl())->isStatic()) &&
5738 "Only non-static member pointers can make it here");
5740 // Okay: this is the address of a non-static member, and therefore
5741 // a member pointer constant.
5742 if (Arg->isTypeDependent() || Arg->isValueDependent()) {
5743 Converted = TemplateArgument(Arg);
5745 ValueDecl *D = cast<ValueDecl>(DRE->getDecl()->getCanonicalDecl());
5746 Converted = TemplateArgument(D, ParamType);
5751 // We found something else, but we don't know specifically what it is.
5752 S.Diag(Arg->getLocStart(),
5753 diag::err_template_arg_not_pointer_to_member_form)
5754 << Arg->getSourceRange();
5755 S.Diag(DRE->getDecl()->getLocation(), diag::note_template_arg_refers_here);
5759 /// \brief Check a template argument against its corresponding
5760 /// non-type template parameter.
5762 /// This routine implements the semantics of C++ [temp.arg.nontype].
5763 /// If an error occurred, it returns ExprError(); otherwise, it
5764 /// returns the converted template argument. \p ParamType is the
5765 /// type of the non-type template parameter after it has been instantiated.
5766 ExprResult Sema::CheckTemplateArgument(NonTypeTemplateParmDecl *Param,
5767 QualType ParamType, Expr *Arg,
5768 TemplateArgument &Converted,
5769 CheckTemplateArgumentKind CTAK) {
5770 SourceLocation StartLoc = Arg->getLocStart();
5772 // If the parameter type somehow involves auto, deduce the type now.
5773 if (getLangOpts().CPlusPlus1z && ParamType->isUndeducedType()) {
5774 // During template argument deduction, we allow 'decltype(auto)' to
5775 // match an arbitrary dependent argument.
5776 // FIXME: The language rules don't say what happens in this case.
5777 // FIXME: We get an opaque dependent type out of decltype(auto) if the
5778 // expression is merely instantiation-dependent; is this enough?
5779 if (CTAK == CTAK_Deduced && Arg->isTypeDependent()) {
5780 auto *AT = dyn_cast<AutoType>(ParamType);
5781 if (AT && AT->isDecltypeAuto()) {
5782 Converted = TemplateArgument(Arg);
5787 // When checking a deduced template argument, deduce from its type even if
5788 // the type is dependent, in order to check the types of non-type template
5789 // arguments line up properly in partial ordering.
5790 Optional<unsigned> Depth;
5791 if (CTAK != CTAK_Specified)
5792 Depth = Param->getDepth() + 1;
5794 Context.getTrivialTypeSourceInfo(ParamType, Param->getLocation()),
5795 Arg, ParamType, Depth) == DAR_Failed) {
5796 Diag(Arg->getExprLoc(),
5797 diag::err_non_type_template_parm_type_deduction_failure)
5798 << Param->getDeclName() << Param->getType() << Arg->getType()
5799 << Arg->getSourceRange();
5800 Diag(Param->getLocation(), diag::note_template_param_here);
5803 // CheckNonTypeTemplateParameterType will produce a diagnostic if there's
5804 // an error. The error message normally references the parameter
5805 // declaration, but here we'll pass the argument location because that's
5806 // where the parameter type is deduced.
5807 ParamType = CheckNonTypeTemplateParameterType(ParamType, Arg->getExprLoc());
5808 if (ParamType.isNull()) {
5809 Diag(Param->getLocation(), diag::note_template_param_here);
5814 // We should have already dropped all cv-qualifiers by now.
5815 assert(!ParamType.hasQualifiers() &&
5816 "non-type template parameter type cannot be qualified");
5818 if (CTAK == CTAK_Deduced &&
5819 !Context.hasSameType(ParamType.getNonLValueExprType(Context),
5821 // FIXME: If either type is dependent, we skip the check. This isn't
5822 // correct, since during deduction we're supposed to have replaced each
5823 // template parameter with some unique (non-dependent) placeholder.
5824 // FIXME: If the argument type contains 'auto', we carry on and fail the
5825 // type check in order to force specific types to be more specialized than
5826 // 'auto'. It's not clear how partial ordering with 'auto' is supposed to
5828 if ((ParamType->isDependentType() || Arg->isTypeDependent()) &&
5829 !Arg->getType()->getContainedAutoType()) {
5830 Converted = TemplateArgument(Arg);
5833 // FIXME: This attempts to implement C++ [temp.deduct.type]p17. Per DR1770,
5834 // we should actually be checking the type of the template argument in P,
5835 // not the type of the template argument deduced from A, against the
5836 // template parameter type.
5837 Diag(StartLoc, diag::err_deduced_non_type_template_arg_type_mismatch)
5839 << ParamType.getUnqualifiedType();
5840 Diag(Param->getLocation(), diag::note_template_param_here);
5844 // If either the parameter has a dependent type or the argument is
5845 // type-dependent, there's nothing we can check now.
5846 if (ParamType->isDependentType() || Arg->isTypeDependent()) {
5847 // FIXME: Produce a cloned, canonical expression?
5848 Converted = TemplateArgument(Arg);
5852 // The initialization of the parameter from the argument is
5853 // a constant-evaluated context.
5854 EnterExpressionEvaluationContext ConstantEvaluated(
5855 *this, Sema::ExpressionEvaluationContext::ConstantEvaluated);
5857 if (getLangOpts().CPlusPlus1z) {
5858 // C++1z [temp.arg.nontype]p1:
5859 // A template-argument for a non-type template parameter shall be
5860 // a converted constant expression of the type of the template-parameter.
5862 ExprResult ArgResult = CheckConvertedConstantExpression(
5863 Arg, ParamType, Value, CCEK_TemplateArg);
5864 if (ArgResult.isInvalid())
5867 // For a value-dependent argument, CheckConvertedConstantExpression is
5868 // permitted (and expected) to be unable to determine a value.
5869 if (ArgResult.get()->isValueDependent()) {
5870 Converted = TemplateArgument(ArgResult.get());
5874 QualType CanonParamType = Context.getCanonicalType(ParamType);
5876 // Convert the APValue to a TemplateArgument.
5877 switch (Value.getKind()) {
5878 case APValue::Uninitialized:
5879 assert(ParamType->isNullPtrType());
5880 Converted = TemplateArgument(CanonParamType, /*isNullPtr*/true);
5883 assert(ParamType->isIntegralOrEnumerationType());
5884 Converted = TemplateArgument(Context, Value.getInt(), CanonParamType);
5886 case APValue::MemberPointer: {
5887 assert(ParamType->isMemberPointerType());
5889 // FIXME: We need TemplateArgument representation and mangling for these.
5890 if (!Value.getMemberPointerPath().empty()) {
5891 Diag(Arg->getLocStart(),
5892 diag::err_template_arg_member_ptr_base_derived_not_supported)
5893 << Value.getMemberPointerDecl() << ParamType
5894 << Arg->getSourceRange();
5898 auto *VD = const_cast<ValueDecl*>(Value.getMemberPointerDecl());
5899 Converted = VD ? TemplateArgument(VD, CanonParamType)
5900 : TemplateArgument(CanonParamType, /*isNullPtr*/true);
5903 case APValue::LValue: {
5904 // For a non-type template-parameter of pointer or reference type,
5905 // the value of the constant expression shall not refer to
5906 assert(ParamType->isPointerType() || ParamType->isReferenceType() ||
5907 ParamType->isNullPtrType());
5908 // -- a temporary object
5909 // -- a string literal
5910 // -- the result of a typeid expression, or
5911 // -- a predefined __func__ variable
5912 if (auto *E = Value.getLValueBase().dyn_cast<const Expr*>()) {
5913 if (isa<CXXUuidofExpr>(E)) {
5914 Converted = TemplateArgument(const_cast<Expr*>(E));
5917 Diag(Arg->getLocStart(), diag::err_template_arg_not_decl_ref)
5918 << Arg->getSourceRange();
5921 auto *VD = const_cast<ValueDecl *>(
5922 Value.getLValueBase().dyn_cast<const ValueDecl *>());
5924 if (Value.hasLValuePath() && Value.getLValuePath().size() == 1 &&
5925 VD && VD->getType()->isArrayType() &&
5926 Value.getLValuePath()[0].ArrayIndex == 0 &&
5927 !Value.isLValueOnePastTheEnd() && ParamType->isPointerType()) {
5928 // Per defect report (no number yet):
5929 // ... other than a pointer to the first element of a complete array
5931 } else if (!Value.hasLValuePath() || Value.getLValuePath().size() ||
5932 Value.isLValueOnePastTheEnd()) {
5933 Diag(StartLoc, diag::err_non_type_template_arg_subobject)
5934 << Value.getAsString(Context, ParamType);
5937 assert((VD || !ParamType->isReferenceType()) &&
5938 "null reference should not be a constant expression");
5939 assert((!VD || !ParamType->isNullPtrType()) &&
5940 "non-null value of type nullptr_t?");
5941 Converted = VD ? TemplateArgument(VD, CanonParamType)
5942 : TemplateArgument(CanonParamType, /*isNullPtr*/true);
5945 case APValue::AddrLabelDiff:
5946 return Diag(StartLoc, diag::err_non_type_template_arg_addr_label_diff);
5947 case APValue::Float:
5948 case APValue::ComplexInt:
5949 case APValue::ComplexFloat:
5950 case APValue::Vector:
5951 case APValue::Array:
5952 case APValue::Struct:
5953 case APValue::Union:
5954 llvm_unreachable("invalid kind for template argument");
5957 return ArgResult.get();
5960 // C++ [temp.arg.nontype]p5:
5961 // The following conversions are performed on each expression used
5962 // as a non-type template-argument. If a non-type
5963 // template-argument cannot be converted to the type of the
5964 // corresponding template-parameter then the program is
5966 if (ParamType->isIntegralOrEnumerationType()) {
5968 // -- for a non-type template-parameter of integral or
5969 // enumeration type, conversions permitted in a converted
5970 // constant expression are applied.
5973 // -- for a non-type template-parameter of integral or
5974 // enumeration type, integral promotions (4.5) and integral
5975 // conversions (4.7) are applied.
5977 if (getLangOpts().CPlusPlus11) {
5978 // C++ [temp.arg.nontype]p1:
5979 // A template-argument for a non-type, non-template template-parameter
5982 // -- for a non-type template-parameter of integral or enumeration
5983 // type, a converted constant expression of the type of the
5984 // template-parameter; or
5986 ExprResult ArgResult =
5987 CheckConvertedConstantExpression(Arg, ParamType, Value,
5989 if (ArgResult.isInvalid())
5992 // We can't check arbitrary value-dependent arguments.
5993 if (ArgResult.get()->isValueDependent()) {
5994 Converted = TemplateArgument(ArgResult.get());
5998 // Widen the argument value to sizeof(parameter type). This is almost
5999 // always a no-op, except when the parameter type is bool. In
6000 // that case, this may extend the argument from 1 bit to 8 bits.
6001 QualType IntegerType = ParamType;
6002 if (const EnumType *Enum = IntegerType->getAs<EnumType>())
6003 IntegerType = Enum->getDecl()->getIntegerType();
6004 Value = Value.extOrTrunc(Context.getTypeSize(IntegerType));
6006 Converted = TemplateArgument(Context, Value,
6007 Context.getCanonicalType(ParamType));
6011 ExprResult ArgResult = DefaultLvalueConversion(Arg);
6012 if (ArgResult.isInvalid())
6014 Arg = ArgResult.get();
6016 QualType ArgType = Arg->getType();
6018 // C++ [temp.arg.nontype]p1:
6019 // A template-argument for a non-type, non-template
6020 // template-parameter shall be one of:
6022 // -- an integral constant-expression of integral or enumeration
6024 // -- the name of a non-type template-parameter; or
6025 SourceLocation NonConstantLoc;
6027 if (!ArgType->isIntegralOrEnumerationType()) {
6028 Diag(Arg->getLocStart(),
6029 diag::err_template_arg_not_integral_or_enumeral)
6030 << ArgType << Arg->getSourceRange();
6031 Diag(Param->getLocation(), diag::note_template_param_here);
6033 } else if (!Arg->isValueDependent()) {
6034 class TmplArgICEDiagnoser : public VerifyICEDiagnoser {
6038 TmplArgICEDiagnoser(QualType T) : T(T) { }
6040 void diagnoseNotICE(Sema &S, SourceLocation Loc,
6041 SourceRange SR) override {
6042 S.Diag(Loc, diag::err_template_arg_not_ice) << T << SR;
6044 } Diagnoser(ArgType);
6046 Arg = VerifyIntegerConstantExpression(Arg, &Value, Diagnoser,
6052 // From here on out, all we care about is the unqualified form
6053 // of the argument type.
6054 ArgType = ArgType.getUnqualifiedType();
6056 // Try to convert the argument to the parameter's type.
6057 if (Context.hasSameType(ParamType, ArgType)) {
6058 // Okay: no conversion necessary
6059 } else if (ParamType->isBooleanType()) {
6060 // This is an integral-to-boolean conversion.
6061 Arg = ImpCastExprToType(Arg, ParamType, CK_IntegralToBoolean).get();
6062 } else if (IsIntegralPromotion(Arg, ArgType, ParamType) ||
6063 !ParamType->isEnumeralType()) {
6064 // This is an integral promotion or conversion.
6065 Arg = ImpCastExprToType(Arg, ParamType, CK_IntegralCast).get();
6067 // We can't perform this conversion.
6068 Diag(Arg->getLocStart(),
6069 diag::err_template_arg_not_convertible)
6070 << Arg->getType() << ParamType << Arg->getSourceRange();
6071 Diag(Param->getLocation(), diag::note_template_param_here);
6075 // Add the value of this argument to the list of converted
6076 // arguments. We use the bitwidth and signedness of the template
6078 if (Arg->isValueDependent()) {
6079 // The argument is value-dependent. Create a new
6080 // TemplateArgument with the converted expression.
6081 Converted = TemplateArgument(Arg);
6085 QualType IntegerType = Context.getCanonicalType(ParamType);
6086 if (const EnumType *Enum = IntegerType->getAs<EnumType>())
6087 IntegerType = Context.getCanonicalType(Enum->getDecl()->getIntegerType());
6089 if (ParamType->isBooleanType()) {
6090 // Value must be zero or one.
6092 unsigned AllowedBits = Context.getTypeSize(IntegerType);
6093 if (Value.getBitWidth() != AllowedBits)
6094 Value = Value.extOrTrunc(AllowedBits);
6095 Value.setIsSigned(IntegerType->isSignedIntegerOrEnumerationType());
6097 llvm::APSInt OldValue = Value;
6099 // Coerce the template argument's value to the value it will have
6100 // based on the template parameter's type.
6101 unsigned AllowedBits = Context.getTypeSize(IntegerType);
6102 if (Value.getBitWidth() != AllowedBits)
6103 Value = Value.extOrTrunc(AllowedBits);
6104 Value.setIsSigned(IntegerType->isSignedIntegerOrEnumerationType());
6106 // Complain if an unsigned parameter received a negative value.
6107 if (IntegerType->isUnsignedIntegerOrEnumerationType()
6108 && (OldValue.isSigned() && OldValue.isNegative())) {
6109 Diag(Arg->getLocStart(), diag::warn_template_arg_negative)
6110 << OldValue.toString(10) << Value.toString(10) << Param->getType()
6111 << Arg->getSourceRange();
6112 Diag(Param->getLocation(), diag::note_template_param_here);
6115 // Complain if we overflowed the template parameter's type.
6116 unsigned RequiredBits;
6117 if (IntegerType->isUnsignedIntegerOrEnumerationType())
6118 RequiredBits = OldValue.getActiveBits();
6119 else if (OldValue.isUnsigned())
6120 RequiredBits = OldValue.getActiveBits() + 1;
6122 RequiredBits = OldValue.getMinSignedBits();
6123 if (RequiredBits > AllowedBits) {
6124 Diag(Arg->getLocStart(),
6125 diag::warn_template_arg_too_large)
6126 << OldValue.toString(10) << Value.toString(10) << Param->getType()
6127 << Arg->getSourceRange();
6128 Diag(Param->getLocation(), diag::note_template_param_here);
6132 Converted = TemplateArgument(Context, Value,
6133 ParamType->isEnumeralType()
6134 ? Context.getCanonicalType(ParamType)
6139 QualType ArgType = Arg->getType();
6140 DeclAccessPair FoundResult; // temporary for ResolveOverloadedFunction
6142 // Handle pointer-to-function, reference-to-function, and
6143 // pointer-to-member-function all in (roughly) the same way.
6144 if (// -- For a non-type template-parameter of type pointer to
6145 // function, only the function-to-pointer conversion (4.3) is
6146 // applied. If the template-argument represents a set of
6147 // overloaded functions (or a pointer to such), the matching
6148 // function is selected from the set (13.4).
6149 (ParamType->isPointerType() &&
6150 ParamType->getAs<PointerType>()->getPointeeType()->isFunctionType()) ||
6151 // -- For a non-type template-parameter of type reference to
6152 // function, no conversions apply. If the template-argument
6153 // represents a set of overloaded functions, the matching
6154 // function is selected from the set (13.4).
6155 (ParamType->isReferenceType() &&
6156 ParamType->getAs<ReferenceType>()->getPointeeType()->isFunctionType()) ||
6157 // -- For a non-type template-parameter of type pointer to
6158 // member function, no conversions apply. If the
6159 // template-argument represents a set of overloaded member
6160 // functions, the matching member function is selected from
6162 (ParamType->isMemberPointerType() &&
6163 ParamType->getAs<MemberPointerType>()->getPointeeType()
6164 ->isFunctionType())) {
6166 if (Arg->getType() == Context.OverloadTy) {
6167 if (FunctionDecl *Fn = ResolveAddressOfOverloadedFunction(Arg, ParamType,
6170 if (DiagnoseUseOfDecl(Fn, Arg->getLocStart()))
6173 Arg = FixOverloadedFunctionReference(Arg, FoundResult, Fn);
6174 ArgType = Arg->getType();
6179 if (!ParamType->isMemberPointerType()) {
6180 if (CheckTemplateArgumentAddressOfObjectOrFunction(*this, Param,
6187 if (CheckTemplateArgumentPointerToMember(*this, Param, ParamType, Arg,
6193 if (ParamType->isPointerType()) {
6194 // -- for a non-type template-parameter of type pointer to
6195 // object, qualification conversions (4.4) and the
6196 // array-to-pointer conversion (4.2) are applied.
6197 // C++0x also allows a value of std::nullptr_t.
6198 assert(ParamType->getPointeeType()->isIncompleteOrObjectType() &&
6199 "Only object pointers allowed here");
6201 if (CheckTemplateArgumentAddressOfObjectOrFunction(*this, Param,
6208 if (const ReferenceType *ParamRefType = ParamType->getAs<ReferenceType>()) {
6209 // -- For a non-type template-parameter of type reference to
6210 // object, no conversions apply. The type referred to by the
6211 // reference may be more cv-qualified than the (otherwise
6212 // identical) type of the template-argument. The
6213 // template-parameter is bound directly to the
6214 // template-argument, which must be an lvalue.
6215 assert(ParamRefType->getPointeeType()->isIncompleteOrObjectType() &&
6216 "Only object references allowed here");
6218 if (Arg->getType() == Context.OverloadTy) {
6219 if (FunctionDecl *Fn = ResolveAddressOfOverloadedFunction(Arg,
6220 ParamRefType->getPointeeType(),
6223 if (DiagnoseUseOfDecl(Fn, Arg->getLocStart()))
6226 Arg = FixOverloadedFunctionReference(Arg, FoundResult, Fn);
6227 ArgType = Arg->getType();
6232 if (CheckTemplateArgumentAddressOfObjectOrFunction(*this, Param,
6239 // Deal with parameters of type std::nullptr_t.
6240 if (ParamType->isNullPtrType()) {
6241 if (Arg->isTypeDependent() || Arg->isValueDependent()) {
6242 Converted = TemplateArgument(Arg);
6246 switch (isNullPointerValueTemplateArgument(*this, Param, ParamType, Arg)) {
6247 case NPV_NotNullPointer:
6248 Diag(Arg->getExprLoc(), diag::err_template_arg_not_convertible)
6249 << Arg->getType() << ParamType;
6250 Diag(Param->getLocation(), diag::note_template_param_here);
6256 case NPV_NullPointer:
6257 Diag(Arg->getExprLoc(), diag::warn_cxx98_compat_template_arg_null);
6258 Converted = TemplateArgument(Context.getCanonicalType(ParamType),
6264 // -- For a non-type template-parameter of type pointer to data
6265 // member, qualification conversions (4.4) are applied.
6266 assert(ParamType->isMemberPointerType() && "Only pointers to members remain");
6268 if (CheckTemplateArgumentPointerToMember(*this, Param, ParamType, Arg,
6274 static void DiagnoseTemplateParameterListArityMismatch(
6275 Sema &S, TemplateParameterList *New, TemplateParameterList *Old,
6276 Sema::TemplateParameterListEqualKind Kind, SourceLocation TemplateArgLoc);
6278 /// \brief Check a template argument against its corresponding
6279 /// template template parameter.
6281 /// This routine implements the semantics of C++ [temp.arg.template].
6282 /// It returns true if an error occurred, and false otherwise.
6283 bool Sema::CheckTemplateArgument(TemplateTemplateParmDecl *Param,
6284 TemplateArgumentLoc &Arg,
6285 unsigned ArgumentPackIndex) {
6286 TemplateName Name = Arg.getArgument().getAsTemplateOrTemplatePattern();
6287 TemplateDecl *Template = Name.getAsTemplateDecl();
6289 // Any dependent template name is fine.
6290 assert(Name.isDependent() && "Non-dependent template isn't a declaration?");
6294 if (Template->isInvalidDecl())
6297 // C++0x [temp.arg.template]p1:
6298 // A template-argument for a template template-parameter shall be
6299 // the name of a class template or an alias template, expressed as an
6300 // id-expression. When the template-argument names a class template, only
6301 // primary class templates are considered when matching the
6302 // template template argument with the corresponding parameter;
6303 // partial specializations are not considered even if their
6304 // parameter lists match that of the template template parameter.
6306 // Note that we also allow template template parameters here, which
6307 // will happen when we are dealing with, e.g., class template
6308 // partial specializations.
6309 if (!isa<ClassTemplateDecl>(Template) &&
6310 !isa<TemplateTemplateParmDecl>(Template) &&
6311 !isa<TypeAliasTemplateDecl>(Template) &&
6312 !isa<BuiltinTemplateDecl>(Template)) {
6313 assert(isa<FunctionTemplateDecl>(Template) &&
6314 "Only function templates are possible here");
6315 Diag(Arg.getLocation(), diag::err_template_arg_not_valid_template);
6316 Diag(Template->getLocation(), diag::note_template_arg_refers_here_func)
6320 TemplateParameterList *Params = Param->getTemplateParameters();
6321 if (Param->isExpandedParameterPack())
6322 Params = Param->getExpansionTemplateParameters(ArgumentPackIndex);
6324 // C++1z [temp.arg.template]p3: (DR 150)
6325 // A template-argument matches a template template-parameter P when P
6326 // is at least as specialized as the template-argument A.
6327 if (getLangOpts().RelaxedTemplateTemplateArgs) {
6328 // Quick check for the common case:
6329 // If P contains a parameter pack, then A [...] matches P if each of A's
6330 // template parameters matches the corresponding template parameter in
6331 // the template-parameter-list of P.
6332 if (TemplateParameterListsAreEqual(
6333 Template->getTemplateParameters(), Params, false,
6334 TPL_TemplateTemplateArgumentMatch, Arg.getLocation()))
6337 if (isTemplateTemplateParameterAtLeastAsSpecializedAs(Params, Template,
6340 // FIXME: Produce better diagnostics for deduction failures.
6343 return !TemplateParameterListsAreEqual(Template->getTemplateParameters(),
6346 TPL_TemplateTemplateArgumentMatch,
6350 /// \brief Given a non-type template argument that refers to a
6351 /// declaration and the type of its corresponding non-type template
6352 /// parameter, produce an expression that properly refers to that
6355 Sema::BuildExpressionFromDeclTemplateArgument(const TemplateArgument &Arg,
6357 SourceLocation Loc) {
6358 // C++ [temp.param]p8:
6360 // A non-type template-parameter of type "array of T" or
6361 // "function returning T" is adjusted to be of type "pointer to
6362 // T" or "pointer to function returning T", respectively.
6363 if (ParamType->isArrayType())
6364 ParamType = Context.getArrayDecayedType(ParamType);
6365 else if (ParamType->isFunctionType())
6366 ParamType = Context.getPointerType(ParamType);
6368 // For a NULL non-type template argument, return nullptr casted to the
6369 // parameter's type.
6370 if (Arg.getKind() == TemplateArgument::NullPtr) {
6371 return ImpCastExprToType(
6372 new (Context) CXXNullPtrLiteralExpr(Context.NullPtrTy, Loc),
6374 ParamType->getAs<MemberPointerType>()
6375 ? CK_NullToMemberPointer
6376 : CK_NullToPointer);
6378 assert(Arg.getKind() == TemplateArgument::Declaration &&
6379 "Only declaration template arguments permitted here");
6381 ValueDecl *VD = cast<ValueDecl>(Arg.getAsDecl());
6383 if (VD->getDeclContext()->isRecord() &&
6384 (isa<CXXMethodDecl>(VD) || isa<FieldDecl>(VD) ||
6385 isa<IndirectFieldDecl>(VD))) {
6386 // If the value is a class member, we might have a pointer-to-member.
6387 // Determine whether the non-type template template parameter is of
6388 // pointer-to-member type. If so, we need to build an appropriate
6389 // expression for a pointer-to-member, since a "normal" DeclRefExpr
6390 // would refer to the member itself.
6391 if (ParamType->isMemberPointerType()) {
6393 = Context.getTypeDeclType(cast<RecordDecl>(VD->getDeclContext()));
6394 NestedNameSpecifier *Qualifier
6395 = NestedNameSpecifier::Create(Context, nullptr, false,
6396 ClassType.getTypePtr());
6398 SS.MakeTrivial(Context, Qualifier, Loc);
6400 // The actual value-ness of this is unimportant, but for
6401 // internal consistency's sake, references to instance methods
6403 ExprValueKind VK = VK_LValue;
6404 if (isa<CXXMethodDecl>(VD) && cast<CXXMethodDecl>(VD)->isInstance())
6407 ExprResult RefExpr = BuildDeclRefExpr(VD,
6408 VD->getType().getNonReferenceType(),
6412 if (RefExpr.isInvalid())
6415 RefExpr = CreateBuiltinUnaryOp(Loc, UO_AddrOf, RefExpr.get());
6417 // We might need to perform a trailing qualification conversion, since
6418 // the element type on the parameter could be more qualified than the
6419 // element type in the expression we constructed.
6420 bool ObjCLifetimeConversion;
6421 if (IsQualificationConversion(((Expr*) RefExpr.get())->getType(),
6422 ParamType.getUnqualifiedType(), false,
6423 ObjCLifetimeConversion))
6424 RefExpr = ImpCastExprToType(RefExpr.get(), ParamType.getUnqualifiedType(), CK_NoOp);
6426 assert(!RefExpr.isInvalid() &&
6427 Context.hasSameType(((Expr*) RefExpr.get())->getType(),
6428 ParamType.getUnqualifiedType()));
6433 QualType T = VD->getType().getNonReferenceType();
6435 if (ParamType->isPointerType()) {
6436 // When the non-type template parameter is a pointer, take the
6437 // address of the declaration.
6438 ExprResult RefExpr = BuildDeclRefExpr(VD, T, VK_LValue, Loc);
6439 if (RefExpr.isInvalid())
6442 if (!Context.hasSameUnqualifiedType(ParamType->getPointeeType(), T) &&
6443 (T->isFunctionType() || T->isArrayType())) {
6444 // Decay functions and arrays unless we're forming a pointer to array.
6445 RefExpr = DefaultFunctionArrayConversion(RefExpr.get());
6446 if (RefExpr.isInvalid())
6452 // Take the address of everything else
6453 return CreateBuiltinUnaryOp(Loc, UO_AddrOf, RefExpr.get());
6456 ExprValueKind VK = VK_RValue;
6458 // If the non-type template parameter has reference type, qualify the
6459 // resulting declaration reference with the extra qualifiers on the
6460 // type that the reference refers to.
6461 if (const ReferenceType *TargetRef = ParamType->getAs<ReferenceType>()) {
6463 T = Context.getQualifiedType(T,
6464 TargetRef->getPointeeType().getQualifiers());
6465 } else if (isa<FunctionDecl>(VD)) {
6466 // References to functions are always lvalues.
6470 return BuildDeclRefExpr(VD, T, VK, Loc);
6473 /// \brief Construct a new expression that refers to the given
6474 /// integral template argument with the given source-location
6477 /// This routine takes care of the mapping from an integral template
6478 /// argument (which may have any integral type) to the appropriate
6481 Sema::BuildExpressionFromIntegralTemplateArgument(const TemplateArgument &Arg,
6482 SourceLocation Loc) {
6483 assert(Arg.getKind() == TemplateArgument::Integral &&
6484 "Operation is only valid for integral template arguments");
6485 QualType OrigT = Arg.getIntegralType();
6487 // If this is an enum type that we're instantiating, we need to use an integer
6488 // type the same size as the enumerator. We don't want to build an
6489 // IntegerLiteral with enum type. The integer type of an enum type can be of
6490 // any integral type with C++11 enum classes, make sure we create the right
6491 // type of literal for it.
6493 if (const EnumType *ET = OrigT->getAs<EnumType>())
6494 T = ET->getDecl()->getIntegerType();
6497 if (T->isAnyCharacterType()) {
6498 // This does not need to handle u8 character literals because those are
6499 // of type char, and so can also be covered by an ASCII character literal.
6500 CharacterLiteral::CharacterKind Kind;
6501 if (T->isWideCharType())
6502 Kind = CharacterLiteral::Wide;
6503 else if (T->isChar16Type())
6504 Kind = CharacterLiteral::UTF16;
6505 else if (T->isChar32Type())
6506 Kind = CharacterLiteral::UTF32;
6508 Kind = CharacterLiteral::Ascii;
6510 E = new (Context) CharacterLiteral(Arg.getAsIntegral().getZExtValue(),
6512 } else if (T->isBooleanType()) {
6513 E = new (Context) CXXBoolLiteralExpr(Arg.getAsIntegral().getBoolValue(),
6515 } else if (T->isNullPtrType()) {
6516 E = new (Context) CXXNullPtrLiteralExpr(Context.NullPtrTy, Loc);
6518 E = IntegerLiteral::Create(Context, Arg.getAsIntegral(), T, Loc);
6521 if (OrigT->isEnumeralType()) {
6522 // FIXME: This is a hack. We need a better way to handle substituted
6523 // non-type template parameters.
6524 E = CStyleCastExpr::Create(Context, OrigT, VK_RValue, CK_IntegralCast, E,
6526 Context.getTrivialTypeSourceInfo(OrigT, Loc),
6533 /// \brief Match two template parameters within template parameter lists.
6534 static bool MatchTemplateParameterKind(Sema &S, NamedDecl *New, NamedDecl *Old,
6536 Sema::TemplateParameterListEqualKind Kind,
6537 SourceLocation TemplateArgLoc) {
6538 // Check the actual kind (type, non-type, template).
6539 if (Old->getKind() != New->getKind()) {
6541 unsigned NextDiag = diag::err_template_param_different_kind;
6542 if (TemplateArgLoc.isValid()) {
6543 S.Diag(TemplateArgLoc, diag::err_template_arg_template_params_mismatch);
6544 NextDiag = diag::note_template_param_different_kind;
6546 S.Diag(New->getLocation(), NextDiag)
6547 << (Kind != Sema::TPL_TemplateMatch);
6548 S.Diag(Old->getLocation(), diag::note_template_prev_declaration)
6549 << (Kind != Sema::TPL_TemplateMatch);
6555 // Check that both are parameter packs or neither are parameter packs.
6556 // However, if we are matching a template template argument to a
6557 // template template parameter, the template template parameter can have
6558 // a parameter pack where the template template argument does not.
6559 if (Old->isTemplateParameterPack() != New->isTemplateParameterPack() &&
6560 !(Kind == Sema::TPL_TemplateTemplateArgumentMatch &&
6561 Old->isTemplateParameterPack())) {
6563 unsigned NextDiag = diag::err_template_parameter_pack_non_pack;
6564 if (TemplateArgLoc.isValid()) {
6565 S.Diag(TemplateArgLoc,
6566 diag::err_template_arg_template_params_mismatch);
6567 NextDiag = diag::note_template_parameter_pack_non_pack;
6570 unsigned ParamKind = isa<TemplateTypeParmDecl>(New)? 0
6571 : isa<NonTypeTemplateParmDecl>(New)? 1
6573 S.Diag(New->getLocation(), NextDiag)
6574 << ParamKind << New->isParameterPack();
6575 S.Diag(Old->getLocation(), diag::note_template_parameter_pack_here)
6576 << ParamKind << Old->isParameterPack();
6582 // For non-type template parameters, check the type of the parameter.
6583 if (NonTypeTemplateParmDecl *OldNTTP
6584 = dyn_cast<NonTypeTemplateParmDecl>(Old)) {
6585 NonTypeTemplateParmDecl *NewNTTP = cast<NonTypeTemplateParmDecl>(New);
6587 // If we are matching a template template argument to a template
6588 // template parameter and one of the non-type template parameter types
6589 // is dependent, then we must wait until template instantiation time
6590 // to actually compare the arguments.
6591 if (Kind == Sema::TPL_TemplateTemplateArgumentMatch &&
6592 (OldNTTP->getType()->isDependentType() ||
6593 NewNTTP->getType()->isDependentType()))
6596 if (!S.Context.hasSameType(OldNTTP->getType(), NewNTTP->getType())) {
6598 unsigned NextDiag = diag::err_template_nontype_parm_different_type;
6599 if (TemplateArgLoc.isValid()) {
6600 S.Diag(TemplateArgLoc,
6601 diag::err_template_arg_template_params_mismatch);
6602 NextDiag = diag::note_template_nontype_parm_different_type;
6604 S.Diag(NewNTTP->getLocation(), NextDiag)
6605 << NewNTTP->getType()
6606 << (Kind != Sema::TPL_TemplateMatch);
6607 S.Diag(OldNTTP->getLocation(),
6608 diag::note_template_nontype_parm_prev_declaration)
6609 << OldNTTP->getType();
6618 // For template template parameters, check the template parameter types.
6619 // The template parameter lists of template template
6620 // parameters must agree.
6621 if (TemplateTemplateParmDecl *OldTTP
6622 = dyn_cast<TemplateTemplateParmDecl>(Old)) {
6623 TemplateTemplateParmDecl *NewTTP = cast<TemplateTemplateParmDecl>(New);
6624 return S.TemplateParameterListsAreEqual(NewTTP->getTemplateParameters(),
6625 OldTTP->getTemplateParameters(),
6627 (Kind == Sema::TPL_TemplateMatch
6628 ? Sema::TPL_TemplateTemplateParmMatch
6636 /// \brief Diagnose a known arity mismatch when comparing template argument
6639 void DiagnoseTemplateParameterListArityMismatch(Sema &S,
6640 TemplateParameterList *New,
6641 TemplateParameterList *Old,
6642 Sema::TemplateParameterListEqualKind Kind,
6643 SourceLocation TemplateArgLoc) {
6644 unsigned NextDiag = diag::err_template_param_list_different_arity;
6645 if (TemplateArgLoc.isValid()) {
6646 S.Diag(TemplateArgLoc, diag::err_template_arg_template_params_mismatch);
6647 NextDiag = diag::note_template_param_list_different_arity;
6649 S.Diag(New->getTemplateLoc(), NextDiag)
6650 << (New->size() > Old->size())
6651 << (Kind != Sema::TPL_TemplateMatch)
6652 << SourceRange(New->getTemplateLoc(), New->getRAngleLoc());
6653 S.Diag(Old->getTemplateLoc(), diag::note_template_prev_declaration)
6654 << (Kind != Sema::TPL_TemplateMatch)
6655 << SourceRange(Old->getTemplateLoc(), Old->getRAngleLoc());
6658 /// \brief Determine whether the given template parameter lists are
6661 /// \param New The new template parameter list, typically written in the
6662 /// source code as part of a new template declaration.
6664 /// \param Old The old template parameter list, typically found via
6665 /// name lookup of the template declared with this template parameter
6668 /// \param Complain If true, this routine will produce a diagnostic if
6669 /// the template parameter lists are not equivalent.
6671 /// \param Kind describes how we are to match the template parameter lists.
6673 /// \param TemplateArgLoc If this source location is valid, then we
6674 /// are actually checking the template parameter list of a template
6675 /// argument (New) against the template parameter list of its
6676 /// corresponding template template parameter (Old). We produce
6677 /// slightly different diagnostics in this scenario.
6679 /// \returns True if the template parameter lists are equal, false
6682 Sema::TemplateParameterListsAreEqual(TemplateParameterList *New,
6683 TemplateParameterList *Old,
6685 TemplateParameterListEqualKind Kind,
6686 SourceLocation TemplateArgLoc) {
6687 if (Old->size() != New->size() && Kind != TPL_TemplateTemplateArgumentMatch) {
6689 DiagnoseTemplateParameterListArityMismatch(*this, New, Old, Kind,
6695 // C++0x [temp.arg.template]p3:
6696 // A template-argument matches a template template-parameter (call it P)
6697 // when each of the template parameters in the template-parameter-list of
6698 // the template-argument's corresponding class template or alias template
6699 // (call it A) matches the corresponding template parameter in the
6700 // template-parameter-list of P. [...]
6701 TemplateParameterList::iterator NewParm = New->begin();
6702 TemplateParameterList::iterator NewParmEnd = New->end();
6703 for (TemplateParameterList::iterator OldParm = Old->begin(),
6704 OldParmEnd = Old->end();
6705 OldParm != OldParmEnd; ++OldParm) {
6706 if (Kind != TPL_TemplateTemplateArgumentMatch ||
6707 !(*OldParm)->isTemplateParameterPack()) {
6708 if (NewParm == NewParmEnd) {
6710 DiagnoseTemplateParameterListArityMismatch(*this, New, Old, Kind,
6716 if (!MatchTemplateParameterKind(*this, *NewParm, *OldParm, Complain,
6717 Kind, TemplateArgLoc))
6724 // C++0x [temp.arg.template]p3:
6725 // [...] When P's template- parameter-list contains a template parameter
6726 // pack (14.5.3), the template parameter pack will match zero or more
6727 // template parameters or template parameter packs in the
6728 // template-parameter-list of A with the same type and form as the
6729 // template parameter pack in P (ignoring whether those template
6730 // parameters are template parameter packs).
6731 for (; NewParm != NewParmEnd; ++NewParm) {
6732 if (!MatchTemplateParameterKind(*this, *NewParm, *OldParm, Complain,
6733 Kind, TemplateArgLoc))
6738 // Make sure we exhausted all of the arguments.
6739 if (NewParm != NewParmEnd) {
6741 DiagnoseTemplateParameterListArityMismatch(*this, New, Old, Kind,
6750 /// \brief Check whether a template can be declared within this scope.
6752 /// If the template declaration is valid in this scope, returns
6753 /// false. Otherwise, issues a diagnostic and returns true.
6755 Sema::CheckTemplateDeclScope(Scope *S, TemplateParameterList *TemplateParams) {
6759 // Find the nearest enclosing declaration scope.
6760 while ((S->getFlags() & Scope::DeclScope) == 0 ||
6761 (S->getFlags() & Scope::TemplateParamScope) != 0)
6765 // A template [...] shall not have C linkage.
6766 DeclContext *Ctx = S->getEntity();
6767 if (Ctx && Ctx->isExternCContext()) {
6768 Diag(TemplateParams->getTemplateLoc(), diag::err_template_linkage)
6769 << TemplateParams->getSourceRange();
6770 if (const LinkageSpecDecl *LSD = Ctx->getExternCContext())
6771 Diag(LSD->getExternLoc(), diag::note_extern_c_begins_here);
6774 Ctx = Ctx->getRedeclContext();
6777 // A template-declaration can appear only as a namespace scope or
6778 // class scope declaration.
6780 if (Ctx->isFileContext())
6782 if (CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(Ctx)) {
6783 // C++ [temp.mem]p2:
6784 // A local class shall not have member templates.
6785 if (RD->isLocalClass())
6786 return Diag(TemplateParams->getTemplateLoc(),
6787 diag::err_template_inside_local_class)
6788 << TemplateParams->getSourceRange();
6794 return Diag(TemplateParams->getTemplateLoc(),
6795 diag::err_template_outside_namespace_or_class_scope)
6796 << TemplateParams->getSourceRange();
6799 /// \brief Determine what kind of template specialization the given declaration
6801 static TemplateSpecializationKind getTemplateSpecializationKind(Decl *D) {
6803 return TSK_Undeclared;
6805 if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(D))
6806 return Record->getTemplateSpecializationKind();
6807 if (FunctionDecl *Function = dyn_cast<FunctionDecl>(D))
6808 return Function->getTemplateSpecializationKind();
6809 if (VarDecl *Var = dyn_cast<VarDecl>(D))
6810 return Var->getTemplateSpecializationKind();
6812 return TSK_Undeclared;
6815 /// \brief Check whether a specialization is well-formed in the current
6818 /// This routine determines whether a template specialization can be declared
6819 /// in the current context (C++ [temp.expl.spec]p2).
6821 /// \param S the semantic analysis object for which this check is being
6824 /// \param Specialized the entity being specialized or instantiated, which
6825 /// may be a kind of template (class template, function template, etc.) or
6826 /// a member of a class template (member function, static data member,
6829 /// \param PrevDecl the previous declaration of this entity, if any.
6831 /// \param Loc the location of the explicit specialization or instantiation of
6834 /// \param IsPartialSpecialization whether this is a partial specialization of
6835 /// a class template.
6837 /// \returns true if there was an error that we cannot recover from, false
6839 static bool CheckTemplateSpecializationScope(Sema &S,
6840 NamedDecl *Specialized,
6841 NamedDecl *PrevDecl,
6843 bool IsPartialSpecialization) {
6844 // Keep these "kind" numbers in sync with the %select statements in the
6845 // various diagnostics emitted by this routine.
6847 if (isa<ClassTemplateDecl>(Specialized))
6848 EntityKind = IsPartialSpecialization? 1 : 0;
6849 else if (isa<VarTemplateDecl>(Specialized))
6850 EntityKind = IsPartialSpecialization ? 3 : 2;
6851 else if (isa<FunctionTemplateDecl>(Specialized))
6853 else if (isa<CXXMethodDecl>(Specialized))
6855 else if (isa<VarDecl>(Specialized))
6857 else if (isa<RecordDecl>(Specialized))
6859 else if (isa<EnumDecl>(Specialized) && S.getLangOpts().CPlusPlus11)
6862 S.Diag(Loc, diag::err_template_spec_unknown_kind)
6863 << S.getLangOpts().CPlusPlus11;
6864 S.Diag(Specialized->getLocation(), diag::note_specialized_entity);
6868 // C++ [temp.expl.spec]p2:
6869 // An explicit specialization shall be declared in the namespace
6870 // of which the template is a member, or, for member templates, in
6871 // the namespace of which the enclosing class or enclosing class
6872 // template is a member. An explicit specialization of a member
6873 // function, member class or static data member of a class
6874 // template shall be declared in the namespace of which the class
6875 // template is a member. Such a declaration may also be a
6876 // definition. If the declaration is not a definition, the
6877 // specialization may be defined later in the name- space in which
6878 // the explicit specialization was declared, or in a namespace
6879 // that encloses the one in which the explicit specialization was
6881 if (S.CurContext->getRedeclContext()->isFunctionOrMethod()) {
6882 S.Diag(Loc, diag::err_template_spec_decl_function_scope)
6887 if (S.CurContext->isRecord() && !IsPartialSpecialization) {
6888 if (S.getLangOpts().MicrosoftExt) {
6889 // Do not warn for class scope explicit specialization during
6890 // instantiation, warning was already emitted during pattern
6891 // semantic analysis.
6892 if (!S.inTemplateInstantiation())
6893 S.Diag(Loc, diag::ext_function_specialization_in_class)
6896 S.Diag(Loc, diag::err_template_spec_decl_class_scope)
6902 if (S.CurContext->isRecord() &&
6903 !S.CurContext->Equals(Specialized->getDeclContext())) {
6904 // Make sure that we're specializing in the right record context.
6905 // Otherwise, things can go horribly wrong.
6906 S.Diag(Loc, diag::err_template_spec_decl_class_scope)
6911 // C++ [temp.class.spec]p6:
6912 // A class template partial specialization may be declared or redeclared
6913 // in any namespace scope in which its definition may be defined (14.5.1
6915 DeclContext *SpecializedContext
6916 = Specialized->getDeclContext()->getEnclosingNamespaceContext();
6917 DeclContext *DC = S.CurContext->getEnclosingNamespaceContext();
6919 // Make sure that this redeclaration (or definition) occurs in an enclosing
6921 // Note that HandleDeclarator() performs this check for explicit
6922 // specializations of function templates, static data members, and member
6923 // functions, so we skip the check here for those kinds of entities.
6924 // FIXME: HandleDeclarator's diagnostics aren't quite as good, though.
6925 // Should we refactor that check, so that it occurs later?
6926 if (!DC->Encloses(SpecializedContext) &&
6927 !(isa<FunctionTemplateDecl>(Specialized) ||
6928 isa<FunctionDecl>(Specialized) ||
6929 isa<VarTemplateDecl>(Specialized) ||
6930 isa<VarDecl>(Specialized))) {
6931 if (isa<TranslationUnitDecl>(SpecializedContext))
6932 S.Diag(Loc, diag::err_template_spec_redecl_global_scope)
6933 << EntityKind << Specialized;
6934 else if (isa<NamespaceDecl>(SpecializedContext)) {
6935 int Diag = diag::err_template_spec_redecl_out_of_scope;
6936 if (S.getLangOpts().MicrosoftExt)
6937 Diag = diag::ext_ms_template_spec_redecl_out_of_scope;
6938 S.Diag(Loc, Diag) << EntityKind << Specialized
6939 << cast<NamedDecl>(SpecializedContext);
6941 llvm_unreachable("unexpected namespace context for specialization");
6943 S.Diag(Specialized->getLocation(), diag::note_specialized_entity);
6944 } else if ((!PrevDecl ||
6945 getTemplateSpecializationKind(PrevDecl) == TSK_Undeclared ||
6946 getTemplateSpecializationKind(PrevDecl) ==
6947 TSK_ImplicitInstantiation)) {
6948 // C++ [temp.exp.spec]p2:
6949 // An explicit specialization shall be declared in the namespace of which
6950 // the template is a member, or, for member templates, in the namespace
6951 // of which the enclosing class or enclosing class template is a member.
6952 // An explicit specialization of a member function, member class or
6953 // static data member of a class template shall be declared in the
6954 // namespace of which the class template is a member.
6956 // C++11 [temp.expl.spec]p2:
6957 // An explicit specialization shall be declared in a namespace enclosing
6958 // the specialized template.
6959 // C++11 [temp.explicit]p3:
6960 // An explicit instantiation shall appear in an enclosing namespace of its
6962 if (!DC->InEnclosingNamespaceSetOf(SpecializedContext)) {
6963 bool IsCPlusPlus11Extension = DC->Encloses(SpecializedContext);
6964 if (isa<TranslationUnitDecl>(SpecializedContext)) {
6965 assert(!IsCPlusPlus11Extension &&
6966 "DC encloses TU but isn't in enclosing namespace set");
6967 S.Diag(Loc, diag::err_template_spec_decl_out_of_scope_global)
6968 << EntityKind << Specialized;
6969 } else if (isa<NamespaceDecl>(SpecializedContext)) {
6971 if (!IsCPlusPlus11Extension)
6972 Diag = diag::err_template_spec_decl_out_of_scope;
6973 else if (!S.getLangOpts().CPlusPlus11)
6974 Diag = diag::ext_template_spec_decl_out_of_scope;
6976 Diag = diag::warn_cxx98_compat_template_spec_decl_out_of_scope;
6978 << EntityKind << Specialized << cast<NamedDecl>(SpecializedContext);
6981 S.Diag(Specialized->getLocation(), diag::note_specialized_entity);
6988 static SourceRange findTemplateParameterInType(unsigned Depth, Expr *E) {
6989 if (!E->isTypeDependent())
6990 return SourceLocation();
6991 DependencyChecker Checker(Depth, /*IgnoreNonTypeDependent*/true);
6992 Checker.TraverseStmt(E);
6993 if (Checker.MatchLoc.isInvalid())
6994 return E->getSourceRange();
6995 return Checker.MatchLoc;
6998 static SourceRange findTemplateParameter(unsigned Depth, TypeLoc TL) {
6999 if (!TL.getType()->isDependentType())
7000 return SourceLocation();
7001 DependencyChecker Checker(Depth, /*IgnoreNonTypeDependent*/true);
7002 Checker.TraverseTypeLoc(TL);
7003 if (Checker.MatchLoc.isInvalid())
7004 return TL.getSourceRange();
7005 return Checker.MatchLoc;
7008 /// \brief Subroutine of Sema::CheckTemplatePartialSpecializationArgs
7009 /// that checks non-type template partial specialization arguments.
7010 static bool CheckNonTypeTemplatePartialSpecializationArgs(
7011 Sema &S, SourceLocation TemplateNameLoc, NonTypeTemplateParmDecl *Param,
7012 const TemplateArgument *Args, unsigned NumArgs, bool IsDefaultArgument) {
7013 for (unsigned I = 0; I != NumArgs; ++I) {
7014 if (Args[I].getKind() == TemplateArgument::Pack) {
7015 if (CheckNonTypeTemplatePartialSpecializationArgs(
7016 S, TemplateNameLoc, Param, Args[I].pack_begin(),
7017 Args[I].pack_size(), IsDefaultArgument))
7023 if (Args[I].getKind() != TemplateArgument::Expression)
7026 Expr *ArgExpr = Args[I].getAsExpr();
7028 // We can have a pack expansion of any of the bullets below.
7029 if (PackExpansionExpr *Expansion = dyn_cast<PackExpansionExpr>(ArgExpr))
7030 ArgExpr = Expansion->getPattern();
7032 // Strip off any implicit casts we added as part of type checking.
7033 while (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(ArgExpr))
7034 ArgExpr = ICE->getSubExpr();
7036 // C++ [temp.class.spec]p8:
7037 // A non-type argument is non-specialized if it is the name of a
7038 // non-type parameter. All other non-type arguments are
7041 // Below, we check the two conditions that only apply to
7042 // specialized non-type arguments, so skip any non-specialized
7044 if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(ArgExpr))
7045 if (isa<NonTypeTemplateParmDecl>(DRE->getDecl()))
7048 // C++ [temp.class.spec]p9:
7049 // Within the argument list of a class template partial
7050 // specialization, the following restrictions apply:
7051 // -- A partially specialized non-type argument expression
7052 // shall not involve a template parameter of the partial
7053 // specialization except when the argument expression is a
7054 // simple identifier.
7055 // -- The type of a template parameter corresponding to a
7056 // specialized non-type argument shall not be dependent on a
7057 // parameter of the specialization.
7058 // DR1315 removes the first bullet, leaving an incoherent set of rules.
7059 // We implement a compromise between the original rules and DR1315:
7060 // -- A specialized non-type template argument shall not be
7061 // type-dependent and the corresponding template parameter
7062 // shall have a non-dependent type.
7063 SourceRange ParamUseRange =
7064 findTemplateParameterInType(Param->getDepth(), ArgExpr);
7065 if (ParamUseRange.isValid()) {
7066 if (IsDefaultArgument) {
7067 S.Diag(TemplateNameLoc,
7068 diag::err_dependent_non_type_arg_in_partial_spec);
7069 S.Diag(ParamUseRange.getBegin(),
7070 diag::note_dependent_non_type_default_arg_in_partial_spec)
7073 S.Diag(ParamUseRange.getBegin(),
7074 diag::err_dependent_non_type_arg_in_partial_spec)
7080 ParamUseRange = findTemplateParameter(
7081 Param->getDepth(), Param->getTypeSourceInfo()->getTypeLoc());
7082 if (ParamUseRange.isValid()) {
7083 S.Diag(IsDefaultArgument ? TemplateNameLoc : ArgExpr->getLocStart(),
7084 diag::err_dependent_typed_non_type_arg_in_partial_spec)
7085 << Param->getType();
7086 S.Diag(Param->getLocation(), diag::note_template_param_here)
7087 << (IsDefaultArgument ? ParamUseRange : SourceRange())
7096 /// \brief Check the non-type template arguments of a class template
7097 /// partial specialization according to C++ [temp.class.spec]p9.
7099 /// \param TemplateNameLoc the location of the template name.
7100 /// \param PrimaryTemplate the template parameters of the primary class
7102 /// \param NumExplicit the number of explicitly-specified template arguments.
7103 /// \param TemplateArgs the template arguments of the class template
7104 /// partial specialization.
7106 /// \returns \c true if there was an error, \c false otherwise.
7107 bool Sema::CheckTemplatePartialSpecializationArgs(
7108 SourceLocation TemplateNameLoc, TemplateDecl *PrimaryTemplate,
7109 unsigned NumExplicit, ArrayRef<TemplateArgument> TemplateArgs) {
7110 // We have to be conservative when checking a template in a dependent
7112 if (PrimaryTemplate->getDeclContext()->isDependentContext())
7115 TemplateParameterList *TemplateParams =
7116 PrimaryTemplate->getTemplateParameters();
7117 for (unsigned I = 0, N = TemplateParams->size(); I != N; ++I) {
7118 NonTypeTemplateParmDecl *Param
7119 = dyn_cast<NonTypeTemplateParmDecl>(TemplateParams->getParam(I));
7123 if (CheckNonTypeTemplatePartialSpecializationArgs(*this, TemplateNameLoc,
7124 Param, &TemplateArgs[I],
7125 1, I >= NumExplicit))
7133 Sema::ActOnClassTemplateSpecialization(Scope *S, unsigned TagSpec,
7135 SourceLocation KWLoc,
7136 SourceLocation ModulePrivateLoc,
7137 TemplateIdAnnotation &TemplateId,
7138 AttributeList *Attr,
7139 MultiTemplateParamsArg
7140 TemplateParameterLists,
7141 SkipBodyInfo *SkipBody) {
7142 assert(TUK != TUK_Reference && "References are not specializations");
7144 CXXScopeSpec &SS = TemplateId.SS;
7146 // NOTE: KWLoc is the location of the tag keyword. This will instead
7147 // store the location of the outermost template keyword in the declaration.
7148 SourceLocation TemplateKWLoc = TemplateParameterLists.size() > 0
7149 ? TemplateParameterLists[0]->getTemplateLoc() : KWLoc;
7150 SourceLocation TemplateNameLoc = TemplateId.TemplateNameLoc;
7151 SourceLocation LAngleLoc = TemplateId.LAngleLoc;
7152 SourceLocation RAngleLoc = TemplateId.RAngleLoc;
7154 // Find the class template we're specializing
7155 TemplateName Name = TemplateId.Template.get();
7156 ClassTemplateDecl *ClassTemplate
7157 = dyn_cast_or_null<ClassTemplateDecl>(Name.getAsTemplateDecl());
7159 if (!ClassTemplate) {
7160 Diag(TemplateNameLoc, diag::err_not_class_template_specialization)
7161 << (Name.getAsTemplateDecl() &&
7162 isa<TemplateTemplateParmDecl>(Name.getAsTemplateDecl()));
7166 bool isMemberSpecialization = false;
7167 bool isPartialSpecialization = false;
7169 // Check the validity of the template headers that introduce this
7171 // FIXME: We probably shouldn't complain about these headers for
7172 // friend declarations.
7173 bool Invalid = false;
7174 TemplateParameterList *TemplateParams =
7175 MatchTemplateParametersToScopeSpecifier(
7176 KWLoc, TemplateNameLoc, SS, &TemplateId,
7177 TemplateParameterLists, TUK == TUK_Friend, isMemberSpecialization,
7182 if (TemplateParams && TemplateParams->size() > 0) {
7183 isPartialSpecialization = true;
7185 if (TUK == TUK_Friend) {
7186 Diag(KWLoc, diag::err_partial_specialization_friend)
7187 << SourceRange(LAngleLoc, RAngleLoc);
7191 // C++ [temp.class.spec]p10:
7192 // The template parameter list of a specialization shall not
7193 // contain default template argument values.
7194 for (unsigned I = 0, N = TemplateParams->size(); I != N; ++I) {
7195 Decl *Param = TemplateParams->getParam(I);
7196 if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(Param)) {
7197 if (TTP->hasDefaultArgument()) {
7198 Diag(TTP->getDefaultArgumentLoc(),
7199 diag::err_default_arg_in_partial_spec);
7200 TTP->removeDefaultArgument();
7202 } else if (NonTypeTemplateParmDecl *NTTP
7203 = dyn_cast<NonTypeTemplateParmDecl>(Param)) {
7204 if (Expr *DefArg = NTTP->getDefaultArgument()) {
7205 Diag(NTTP->getDefaultArgumentLoc(),
7206 diag::err_default_arg_in_partial_spec)
7207 << DefArg->getSourceRange();
7208 NTTP->removeDefaultArgument();
7211 TemplateTemplateParmDecl *TTP = cast<TemplateTemplateParmDecl>(Param);
7212 if (TTP->hasDefaultArgument()) {
7213 Diag(TTP->getDefaultArgument().getLocation(),
7214 diag::err_default_arg_in_partial_spec)
7215 << TTP->getDefaultArgument().getSourceRange();
7216 TTP->removeDefaultArgument();
7220 } else if (TemplateParams) {
7221 if (TUK == TUK_Friend)
7222 Diag(KWLoc, diag::err_template_spec_friend)
7223 << FixItHint::CreateRemoval(
7224 SourceRange(TemplateParams->getTemplateLoc(),
7225 TemplateParams->getRAngleLoc()))
7226 << SourceRange(LAngleLoc, RAngleLoc);
7228 assert(TUK == TUK_Friend && "should have a 'template<>' for this decl");
7231 // Check that the specialization uses the same tag kind as the
7232 // original template.
7233 TagTypeKind Kind = TypeWithKeyword::getTagTypeKindForTypeSpec(TagSpec);
7234 assert(Kind != TTK_Enum && "Invalid enum tag in class template spec!");
7235 if (!isAcceptableTagRedeclaration(ClassTemplate->getTemplatedDecl(),
7236 Kind, TUK == TUK_Definition, KWLoc,
7237 ClassTemplate->getIdentifier())) {
7238 Diag(KWLoc, diag::err_use_with_wrong_tag)
7240 << FixItHint::CreateReplacement(KWLoc,
7241 ClassTemplate->getTemplatedDecl()->getKindName());
7242 Diag(ClassTemplate->getTemplatedDecl()->getLocation(),
7243 diag::note_previous_use);
7244 Kind = ClassTemplate->getTemplatedDecl()->getTagKind();
7247 // Translate the parser's template argument list in our AST format.
7248 TemplateArgumentListInfo TemplateArgs =
7249 makeTemplateArgumentListInfo(*this, TemplateId);
7251 // Check for unexpanded parameter packs in any of the template arguments.
7252 for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I)
7253 if (DiagnoseUnexpandedParameterPack(TemplateArgs[I],
7254 UPPC_PartialSpecialization))
7257 // Check that the template argument list is well-formed for this
7259 SmallVector<TemplateArgument, 4> Converted;
7260 if (CheckTemplateArgumentList(ClassTemplate, TemplateNameLoc,
7261 TemplateArgs, false, Converted))
7264 // Find the class template (partial) specialization declaration that
7265 // corresponds to these arguments.
7266 if (isPartialSpecialization) {
7267 if (CheckTemplatePartialSpecializationArgs(TemplateNameLoc, ClassTemplate,
7268 TemplateArgs.size(), Converted))
7271 // FIXME: Move this to CheckTemplatePartialSpecializationArgs so we
7272 // also do it during instantiation.
7273 bool InstantiationDependent;
7274 if (!Name.isDependent() &&
7275 !TemplateSpecializationType::anyDependentTemplateArguments(
7276 TemplateArgs.arguments(), InstantiationDependent)) {
7277 Diag(TemplateNameLoc, diag::err_partial_spec_fully_specialized)
7278 << ClassTemplate->getDeclName();
7279 isPartialSpecialization = false;
7283 void *InsertPos = nullptr;
7284 ClassTemplateSpecializationDecl *PrevDecl = nullptr;
7286 if (isPartialSpecialization)
7287 // FIXME: Template parameter list matters, too
7288 PrevDecl = ClassTemplate->findPartialSpecialization(Converted, InsertPos);
7290 PrevDecl = ClassTemplate->findSpecialization(Converted, InsertPos);
7292 ClassTemplateSpecializationDecl *Specialization = nullptr;
7294 // Check whether we can declare a class template specialization in
7295 // the current scope.
7296 if (TUK != TUK_Friend &&
7297 CheckTemplateSpecializationScope(*this, ClassTemplate, PrevDecl,
7299 isPartialSpecialization))
7302 // The canonical type
7304 if (isPartialSpecialization) {
7305 // Build the canonical type that describes the converted template
7306 // arguments of the class template partial specialization.
7307 TemplateName CanonTemplate = Context.getCanonicalTemplateName(Name);
7308 CanonType = Context.getTemplateSpecializationType(CanonTemplate,
7311 if (Context.hasSameType(CanonType,
7312 ClassTemplate->getInjectedClassNameSpecialization())) {
7313 // C++ [temp.class.spec]p9b3:
7315 // -- The argument list of the specialization shall not be identical
7316 // to the implicit argument list of the primary template.
7318 // This rule has since been removed, because it's redundant given DR1495,
7319 // but we keep it because it produces better diagnostics and recovery.
7320 Diag(TemplateNameLoc, diag::err_partial_spec_args_match_primary_template)
7321 << /*class template*/0 << (TUK == TUK_Definition)
7322 << FixItHint::CreateRemoval(SourceRange(LAngleLoc, RAngleLoc));
7323 return CheckClassTemplate(S, TagSpec, TUK, KWLoc, SS,
7324 ClassTemplate->getIdentifier(),
7328 AS_none, /*ModulePrivateLoc=*/SourceLocation(),
7329 /*FriendLoc*/SourceLocation(),
7330 TemplateParameterLists.size() - 1,
7331 TemplateParameterLists.data());
7334 // Create a new class template partial specialization declaration node.
7335 ClassTemplatePartialSpecializationDecl *PrevPartial
7336 = cast_or_null<ClassTemplatePartialSpecializationDecl>(PrevDecl);
7337 ClassTemplatePartialSpecializationDecl *Partial
7338 = ClassTemplatePartialSpecializationDecl::Create(Context, Kind,
7339 ClassTemplate->getDeclContext(),
7340 KWLoc, TemplateNameLoc,
7347 SetNestedNameSpecifier(Partial, SS);
7348 if (TemplateParameterLists.size() > 1 && SS.isSet()) {
7349 Partial->setTemplateParameterListsInfo(
7350 Context, TemplateParameterLists.drop_back(1));
7354 ClassTemplate->AddPartialSpecialization(Partial, InsertPos);
7355 Specialization = Partial;
7357 // If we are providing an explicit specialization of a member class
7358 // template specialization, make a note of that.
7359 if (PrevPartial && PrevPartial->getInstantiatedFromMember())
7360 PrevPartial->setMemberSpecialization();
7362 CheckTemplatePartialSpecialization(Partial);
7364 // Create a new class template specialization declaration node for
7365 // this explicit specialization or friend declaration.
7367 = ClassTemplateSpecializationDecl::Create(Context, Kind,
7368 ClassTemplate->getDeclContext(),
7369 KWLoc, TemplateNameLoc,
7373 SetNestedNameSpecifier(Specialization, SS);
7374 if (TemplateParameterLists.size() > 0) {
7375 Specialization->setTemplateParameterListsInfo(Context,
7376 TemplateParameterLists);
7380 ClassTemplate->AddSpecialization(Specialization, InsertPos);
7382 if (CurContext->isDependentContext()) {
7383 // -fms-extensions permits specialization of nested classes without
7384 // fully specializing the outer class(es).
7385 assert(getLangOpts().MicrosoftExt &&
7386 "Only possible with -fms-extensions!");
7387 TemplateName CanonTemplate = Context.getCanonicalTemplateName(Name);
7388 CanonType = Context.getTemplateSpecializationType(
7389 CanonTemplate, Converted);
7391 CanonType = Context.getTypeDeclType(Specialization);
7395 // C++ [temp.expl.spec]p6:
7396 // If a template, a member template or the member of a class template is
7397 // explicitly specialized then that specialization shall be declared
7398 // before the first use of that specialization that would cause an implicit
7399 // instantiation to take place, in every translation unit in which such a
7400 // use occurs; no diagnostic is required.
7401 if (PrevDecl && PrevDecl->getPointOfInstantiation().isValid()) {
7403 for (Decl *Prev = PrevDecl; Prev; Prev = Prev->getPreviousDecl()) {
7404 // Is there any previous explicit specialization declaration?
7405 if (getTemplateSpecializationKind(Prev) == TSK_ExplicitSpecialization) {
7412 SourceRange Range(TemplateNameLoc, RAngleLoc);
7413 Diag(TemplateNameLoc, diag::err_specialization_after_instantiation)
7414 << Context.getTypeDeclType(Specialization) << Range;
7416 Diag(PrevDecl->getPointOfInstantiation(),
7417 diag::note_instantiation_required_here)
7418 << (PrevDecl->getTemplateSpecializationKind()
7419 != TSK_ImplicitInstantiation);
7424 // If this is not a friend, note that this is an explicit specialization.
7425 if (TUK != TUK_Friend)
7426 Specialization->setSpecializationKind(TSK_ExplicitSpecialization);
7428 // Check that this isn't a redefinition of this specialization.
7429 if (TUK == TUK_Definition) {
7430 RecordDecl *Def = Specialization->getDefinition();
7431 NamedDecl *Hidden = nullptr;
7432 if (Def && SkipBody && !hasVisibleDefinition(Def, &Hidden)) {
7433 SkipBody->ShouldSkip = true;
7434 makeMergedDefinitionVisible(Hidden);
7435 // From here on out, treat this as just a redeclaration.
7436 TUK = TUK_Declaration;
7438 SourceRange Range(TemplateNameLoc, RAngleLoc);
7439 Diag(TemplateNameLoc, diag::err_redefinition) << Specialization << Range;
7440 Diag(Def->getLocation(), diag::note_previous_definition);
7441 Specialization->setInvalidDecl();
7447 ProcessDeclAttributeList(S, Specialization, Attr);
7449 // Add alignment attributes if necessary; these attributes are checked when
7450 // the ASTContext lays out the structure.
7451 if (TUK == TUK_Definition) {
7452 AddAlignmentAttributesForRecord(Specialization);
7453 AddMsStructLayoutForRecord(Specialization);
7456 if (ModulePrivateLoc.isValid())
7457 Diag(Specialization->getLocation(), diag::err_module_private_specialization)
7458 << (isPartialSpecialization? 1 : 0)
7459 << FixItHint::CreateRemoval(ModulePrivateLoc);
7461 // Build the fully-sugared type for this class template
7462 // specialization as the user wrote in the specialization
7463 // itself. This means that we'll pretty-print the type retrieved
7464 // from the specialization's declaration the way that the user
7465 // actually wrote the specialization, rather than formatting the
7466 // name based on the "canonical" representation used to store the
7467 // template arguments in the specialization.
7468 TypeSourceInfo *WrittenTy
7469 = Context.getTemplateSpecializationTypeInfo(Name, TemplateNameLoc,
7470 TemplateArgs, CanonType);
7471 if (TUK != TUK_Friend) {
7472 Specialization->setTypeAsWritten(WrittenTy);
7473 Specialization->setTemplateKeywordLoc(TemplateKWLoc);
7476 // C++ [temp.expl.spec]p9:
7477 // A template explicit specialization is in the scope of the
7478 // namespace in which the template was defined.
7480 // We actually implement this paragraph where we set the semantic
7481 // context (in the creation of the ClassTemplateSpecializationDecl),
7482 // but we also maintain the lexical context where the actual
7483 // definition occurs.
7484 Specialization->setLexicalDeclContext(CurContext);
7486 // We may be starting the definition of this specialization.
7487 if (TUK == TUK_Definition)
7488 Specialization->startDefinition();
7490 if (TUK == TUK_Friend) {
7491 FriendDecl *Friend = FriendDecl::Create(Context, CurContext,
7495 Friend->setAccess(AS_public);
7496 CurContext->addDecl(Friend);
7498 // Add the specialization into its lexical context, so that it can
7499 // be seen when iterating through the list of declarations in that
7500 // context. However, specializations are not found by name lookup.
7501 CurContext->addDecl(Specialization);
7503 return Specialization;
7506 Decl *Sema::ActOnTemplateDeclarator(Scope *S,
7507 MultiTemplateParamsArg TemplateParameterLists,
7509 Decl *NewDecl = HandleDeclarator(S, D, TemplateParameterLists);
7510 ActOnDocumentableDecl(NewDecl);
7514 /// \brief Strips various properties off an implicit instantiation
7515 /// that has just been explicitly specialized.
7516 static void StripImplicitInstantiation(NamedDecl *D) {
7517 D->dropAttr<DLLImportAttr>();
7518 D->dropAttr<DLLExportAttr>();
7520 if (FunctionDecl *FD = dyn_cast<FunctionDecl>(D))
7521 FD->setInlineSpecified(false);
7524 /// \brief Compute the diagnostic location for an explicit instantiation
7525 // declaration or definition.
7526 static SourceLocation DiagLocForExplicitInstantiation(
7527 NamedDecl* D, SourceLocation PointOfInstantiation) {
7528 // Explicit instantiations following a specialization have no effect and
7529 // hence no PointOfInstantiation. In that case, walk decl backwards
7530 // until a valid name loc is found.
7531 SourceLocation PrevDiagLoc = PointOfInstantiation;
7532 for (Decl *Prev = D; Prev && !PrevDiagLoc.isValid();
7533 Prev = Prev->getPreviousDecl()) {
7534 PrevDiagLoc = Prev->getLocation();
7536 assert(PrevDiagLoc.isValid() &&
7537 "Explicit instantiation without point of instantiation?");
7541 /// \brief Diagnose cases where we have an explicit template specialization
7542 /// before/after an explicit template instantiation, producing diagnostics
7543 /// for those cases where they are required and determining whether the
7544 /// new specialization/instantiation will have any effect.
7546 /// \param NewLoc the location of the new explicit specialization or
7549 /// \param NewTSK the kind of the new explicit specialization or instantiation.
7551 /// \param PrevDecl the previous declaration of the entity.
7553 /// \param PrevTSK the kind of the old explicit specialization or instantiatin.
7555 /// \param PrevPointOfInstantiation if valid, indicates where the previus
7556 /// declaration was instantiated (either implicitly or explicitly).
7558 /// \param HasNoEffect will be set to true to indicate that the new
7559 /// specialization or instantiation has no effect and should be ignored.
7561 /// \returns true if there was an error that should prevent the introduction of
7562 /// the new declaration into the AST, false otherwise.
7564 Sema::CheckSpecializationInstantiationRedecl(SourceLocation NewLoc,
7565 TemplateSpecializationKind NewTSK,
7566 NamedDecl *PrevDecl,
7567 TemplateSpecializationKind PrevTSK,
7568 SourceLocation PrevPointOfInstantiation,
7569 bool &HasNoEffect) {
7570 HasNoEffect = false;
7573 case TSK_Undeclared:
7574 case TSK_ImplicitInstantiation:
7576 (PrevTSK == TSK_Undeclared || PrevTSK == TSK_ImplicitInstantiation) &&
7577 "previous declaration must be implicit!");
7580 case TSK_ExplicitSpecialization:
7582 case TSK_Undeclared:
7583 case TSK_ExplicitSpecialization:
7584 // Okay, we're just specializing something that is either already
7585 // explicitly specialized or has merely been mentioned without any
7589 case TSK_ImplicitInstantiation:
7590 if (PrevPointOfInstantiation.isInvalid()) {
7591 // The declaration itself has not actually been instantiated, so it is
7592 // still okay to specialize it.
7593 StripImplicitInstantiation(PrevDecl);
7598 case TSK_ExplicitInstantiationDeclaration:
7599 case TSK_ExplicitInstantiationDefinition:
7600 assert((PrevTSK == TSK_ImplicitInstantiation ||
7601 PrevPointOfInstantiation.isValid()) &&
7602 "Explicit instantiation without point of instantiation?");
7604 // C++ [temp.expl.spec]p6:
7605 // If a template, a member template or the member of a class template
7606 // is explicitly specialized then that specialization shall be declared
7607 // before the first use of that specialization that would cause an
7608 // implicit instantiation to take place, in every translation unit in
7609 // which such a use occurs; no diagnostic is required.
7610 for (Decl *Prev = PrevDecl; Prev; Prev = Prev->getPreviousDecl()) {
7611 // Is there any previous explicit specialization declaration?
7612 if (getTemplateSpecializationKind(Prev) == TSK_ExplicitSpecialization)
7616 Diag(NewLoc, diag::err_specialization_after_instantiation)
7618 Diag(PrevPointOfInstantiation, diag::note_instantiation_required_here)
7619 << (PrevTSK != TSK_ImplicitInstantiation);
7624 case TSK_ExplicitInstantiationDeclaration:
7626 case TSK_ExplicitInstantiationDeclaration:
7627 // This explicit instantiation declaration is redundant (that's okay).
7631 case TSK_Undeclared:
7632 case TSK_ImplicitInstantiation:
7633 // We're explicitly instantiating something that may have already been
7634 // implicitly instantiated; that's fine.
7637 case TSK_ExplicitSpecialization:
7638 // C++0x [temp.explicit]p4:
7639 // For a given set of template parameters, if an explicit instantiation
7640 // of a template appears after a declaration of an explicit
7641 // specialization for that template, the explicit instantiation has no
7646 case TSK_ExplicitInstantiationDefinition:
7647 // C++0x [temp.explicit]p10:
7648 // If an entity is the subject of both an explicit instantiation
7649 // declaration and an explicit instantiation definition in the same
7650 // translation unit, the definition shall follow the declaration.
7652 diag::err_explicit_instantiation_declaration_after_definition);
7654 // Explicit instantiations following a specialization have no effect and
7655 // hence no PrevPointOfInstantiation. In that case, walk decl backwards
7656 // until a valid name loc is found.
7657 Diag(DiagLocForExplicitInstantiation(PrevDecl, PrevPointOfInstantiation),
7658 diag::note_explicit_instantiation_definition_here);
7663 case TSK_ExplicitInstantiationDefinition:
7665 case TSK_Undeclared:
7666 case TSK_ImplicitInstantiation:
7667 // We're explicitly instantiating something that may have already been
7668 // implicitly instantiated; that's fine.
7671 case TSK_ExplicitSpecialization:
7672 // C++ DR 259, C++0x [temp.explicit]p4:
7673 // For a given set of template parameters, if an explicit
7674 // instantiation of a template appears after a declaration of
7675 // an explicit specialization for that template, the explicit
7676 // instantiation has no effect.
7677 Diag(NewLoc, diag::warn_explicit_instantiation_after_specialization)
7679 Diag(PrevDecl->getLocation(),
7680 diag::note_previous_template_specialization);
7684 case TSK_ExplicitInstantiationDeclaration:
7685 // We're explicity instantiating a definition for something for which we
7686 // were previously asked to suppress instantiations. That's fine.
7688 // C++0x [temp.explicit]p4:
7689 // For a given set of template parameters, if an explicit instantiation
7690 // of a template appears after a declaration of an explicit
7691 // specialization for that template, the explicit instantiation has no
7693 for (Decl *Prev = PrevDecl; Prev; Prev = Prev->getPreviousDecl()) {
7694 // Is there any previous explicit specialization declaration?
7695 if (getTemplateSpecializationKind(Prev) == TSK_ExplicitSpecialization) {
7703 case TSK_ExplicitInstantiationDefinition:
7704 // C++0x [temp.spec]p5:
7705 // For a given template and a given set of template-arguments,
7706 // - an explicit instantiation definition shall appear at most once
7709 // MSVCCompat: MSVC silently ignores duplicate explicit instantiations.
7710 Diag(NewLoc, (getLangOpts().MSVCCompat)
7711 ? diag::ext_explicit_instantiation_duplicate
7712 : diag::err_explicit_instantiation_duplicate)
7714 Diag(DiagLocForExplicitInstantiation(PrevDecl, PrevPointOfInstantiation),
7715 diag::note_previous_explicit_instantiation);
7721 llvm_unreachable("Missing specialization/instantiation case?");
7724 /// \brief Perform semantic analysis for the given dependent function
7725 /// template specialization.
7727 /// The only possible way to get a dependent function template specialization
7728 /// is with a friend declaration, like so:
7731 /// template \<class T> void foo(T);
7732 /// template \<class T> class A {
7733 /// friend void foo<>(T);
7737 /// There really isn't any useful analysis we can do here, so we
7738 /// just store the information.
7740 Sema::CheckDependentFunctionTemplateSpecialization(FunctionDecl *FD,
7741 const TemplateArgumentListInfo &ExplicitTemplateArgs,
7742 LookupResult &Previous) {
7743 // Remove anything from Previous that isn't a function template in
7744 // the correct context.
7745 DeclContext *FDLookupContext = FD->getDeclContext()->getRedeclContext();
7746 LookupResult::Filter F = Previous.makeFilter();
7747 while (F.hasNext()) {
7748 NamedDecl *D = F.next()->getUnderlyingDecl();
7749 if (!isa<FunctionTemplateDecl>(D) ||
7750 !FDLookupContext->InEnclosingNamespaceSetOf(
7751 D->getDeclContext()->getRedeclContext()))
7756 // Should this be diagnosed here?
7757 if (Previous.empty()) return true;
7759 FD->setDependentTemplateSpecialization(Context, Previous.asUnresolvedSet(),
7760 ExplicitTemplateArgs);
7764 /// \brief Perform semantic analysis for the given function template
7767 /// This routine performs all of the semantic analysis required for an
7768 /// explicit function template specialization. On successful completion,
7769 /// the function declaration \p FD will become a function template
7772 /// \param FD the function declaration, which will be updated to become a
7773 /// function template specialization.
7775 /// \param ExplicitTemplateArgs the explicitly-provided template arguments,
7776 /// if any. Note that this may be valid info even when 0 arguments are
7777 /// explicitly provided as in, e.g., \c void sort<>(char*, char*);
7778 /// as it anyway contains info on the angle brackets locations.
7780 /// \param Previous the set of declarations that may be specialized by
7781 /// this function specialization.
7782 bool Sema::CheckFunctionTemplateSpecialization(
7783 FunctionDecl *FD, TemplateArgumentListInfo *ExplicitTemplateArgs,
7784 LookupResult &Previous) {
7785 // The set of function template specializations that could match this
7786 // explicit function template specialization.
7787 UnresolvedSet<8> Candidates;
7788 TemplateSpecCandidateSet FailedCandidates(FD->getLocation(),
7789 /*ForTakingAddress=*/false);
7791 llvm::SmallDenseMap<FunctionDecl *, TemplateArgumentListInfo, 8>
7792 ConvertedTemplateArgs;
7794 DeclContext *FDLookupContext = FD->getDeclContext()->getRedeclContext();
7795 for (LookupResult::iterator I = Previous.begin(), E = Previous.end();
7797 NamedDecl *Ovl = (*I)->getUnderlyingDecl();
7798 if (FunctionTemplateDecl *FunTmpl = dyn_cast<FunctionTemplateDecl>(Ovl)) {
7799 // Only consider templates found within the same semantic lookup scope as
7801 if (!FDLookupContext->InEnclosingNamespaceSetOf(
7802 Ovl->getDeclContext()->getRedeclContext()))
7805 // When matching a constexpr member function template specialization
7806 // against the primary template, we don't yet know whether the
7807 // specialization has an implicit 'const' (because we don't know whether
7808 // it will be a static member function until we know which template it
7809 // specializes), so adjust it now assuming it specializes this template.
7810 QualType FT = FD->getType();
7811 if (FD->isConstexpr()) {
7812 CXXMethodDecl *OldMD =
7813 dyn_cast<CXXMethodDecl>(FunTmpl->getTemplatedDecl());
7814 if (OldMD && OldMD->isConst()) {
7815 const FunctionProtoType *FPT = FT->castAs<FunctionProtoType>();
7816 FunctionProtoType::ExtProtoInfo EPI = FPT->getExtProtoInfo();
7817 EPI.TypeQuals |= Qualifiers::Const;
7818 FT = Context.getFunctionType(FPT->getReturnType(),
7819 FPT->getParamTypes(), EPI);
7823 TemplateArgumentListInfo Args;
7824 if (ExplicitTemplateArgs)
7825 Args = *ExplicitTemplateArgs;
7827 // C++ [temp.expl.spec]p11:
7828 // A trailing template-argument can be left unspecified in the
7829 // template-id naming an explicit function template specialization
7830 // provided it can be deduced from the function argument type.
7831 // Perform template argument deduction to determine whether we may be
7832 // specializing this template.
7833 // FIXME: It is somewhat wasteful to build
7834 TemplateDeductionInfo Info(FailedCandidates.getLocation());
7835 FunctionDecl *Specialization = nullptr;
7836 if (TemplateDeductionResult TDK = DeduceTemplateArguments(
7837 cast<FunctionTemplateDecl>(FunTmpl->getFirstDecl()),
7838 ExplicitTemplateArgs ? &Args : nullptr, FT, Specialization,
7840 // Template argument deduction failed; record why it failed, so
7841 // that we can provide nifty diagnostics.
7842 FailedCandidates.addCandidate().set(
7843 I.getPair(), FunTmpl->getTemplatedDecl(),
7844 MakeDeductionFailureInfo(Context, TDK, Info));
7849 // Target attributes are part of the cuda function signature, so
7850 // the deduced template's cuda target must match that of the
7851 // specialization. Given that C++ template deduction does not
7852 // take target attributes into account, we reject candidates
7853 // here that have a different target.
7854 if (LangOpts.CUDA &&
7855 IdentifyCUDATarget(Specialization,
7856 /* IgnoreImplicitHDAttributes = */ true) !=
7857 IdentifyCUDATarget(FD, /* IgnoreImplicitHDAttributes = */ true)) {
7858 FailedCandidates.addCandidate().set(
7859 I.getPair(), FunTmpl->getTemplatedDecl(),
7860 MakeDeductionFailureInfo(Context, TDK_CUDATargetMismatch, Info));
7864 // Record this candidate.
7865 if (ExplicitTemplateArgs)
7866 ConvertedTemplateArgs[Specialization] = std::move(Args);
7867 Candidates.addDecl(Specialization, I.getAccess());
7871 // Find the most specialized function template.
7872 UnresolvedSetIterator Result = getMostSpecialized(
7873 Candidates.begin(), Candidates.end(), FailedCandidates,
7875 PDiag(diag::err_function_template_spec_no_match) << FD->getDeclName(),
7876 PDiag(diag::err_function_template_spec_ambiguous)
7877 << FD->getDeclName() << (ExplicitTemplateArgs != nullptr),
7878 PDiag(diag::note_function_template_spec_matched));
7880 if (Result == Candidates.end())
7883 // Ignore access information; it doesn't figure into redeclaration checking.
7884 FunctionDecl *Specialization = cast<FunctionDecl>(*Result);
7886 // C++ Concepts TS [dcl.spec.concept]p7: A program shall not declare [...]
7887 // an explicit specialization (14.8.3) [...] of a concept definition.
7888 if (Specialization->getPrimaryTemplate()->isConcept()) {
7889 Diag(FD->getLocation(), diag::err_concept_specialized)
7890 << 0 /*function*/ << 1 /*explicitly specialized*/;
7891 Diag(Specialization->getLocation(), diag::note_previous_declaration);
7895 FunctionTemplateSpecializationInfo *SpecInfo
7896 = Specialization->getTemplateSpecializationInfo();
7897 assert(SpecInfo && "Function template specialization info missing?");
7899 // Note: do not overwrite location info if previous template
7900 // specialization kind was explicit.
7901 TemplateSpecializationKind TSK = SpecInfo->getTemplateSpecializationKind();
7902 if (TSK == TSK_Undeclared || TSK == TSK_ImplicitInstantiation) {
7903 Specialization->setLocation(FD->getLocation());
7904 Specialization->setLexicalDeclContext(FD->getLexicalDeclContext());
7905 // C++11 [dcl.constexpr]p1: An explicit specialization of a constexpr
7906 // function can differ from the template declaration with respect to
7907 // the constexpr specifier.
7908 // FIXME: We need an update record for this AST mutation.
7909 // FIXME: What if there are multiple such prior declarations (for instance,
7910 // from different modules)?
7911 Specialization->setConstexpr(FD->isConstexpr());
7914 // FIXME: Check if the prior specialization has a point of instantiation.
7915 // If so, we have run afoul of .
7917 // If this is a friend declaration, then we're not really declaring
7918 // an explicit specialization.
7919 bool isFriend = (FD->getFriendObjectKind() != Decl::FOK_None);
7921 // Check the scope of this explicit specialization.
7923 CheckTemplateSpecializationScope(*this,
7924 Specialization->getPrimaryTemplate(),
7925 Specialization, FD->getLocation(),
7929 // C++ [temp.expl.spec]p6:
7930 // If a template, a member template or the member of a class template is
7931 // explicitly specialized then that specialization shall be declared
7932 // before the first use of that specialization that would cause an implicit
7933 // instantiation to take place, in every translation unit in which such a
7934 // use occurs; no diagnostic is required.
7935 bool HasNoEffect = false;
7937 CheckSpecializationInstantiationRedecl(FD->getLocation(),
7938 TSK_ExplicitSpecialization,
7940 SpecInfo->getTemplateSpecializationKind(),
7941 SpecInfo->getPointOfInstantiation(),
7945 // Mark the prior declaration as an explicit specialization, so that later
7946 // clients know that this is an explicit specialization.
7948 // Since explicit specializations do not inherit '=delete' from their
7949 // primary function template - check if the 'specialization' that was
7950 // implicitly generated (during template argument deduction for partial
7951 // ordering) from the most specialized of all the function templates that
7952 // 'FD' could have been specializing, has a 'deleted' definition. If so,
7953 // first check that it was implicitly generated during template argument
7954 // deduction by making sure it wasn't referenced, and then reset the deleted
7955 // flag to not-deleted, so that we can inherit that information from 'FD'.
7956 if (Specialization->isDeleted() && !SpecInfo->isExplicitSpecialization() &&
7957 !Specialization->getCanonicalDecl()->isReferenced()) {
7958 // FIXME: This assert will not hold in the presence of modules.
7960 Specialization->getCanonicalDecl() == Specialization &&
7961 "This must be the only existing declaration of this specialization");
7962 // FIXME: We need an update record for this AST mutation.
7963 Specialization->setDeletedAsWritten(false);
7965 // FIXME: We need an update record for this AST mutation.
7966 SpecInfo->setTemplateSpecializationKind(TSK_ExplicitSpecialization);
7967 MarkUnusedFileScopedDecl(Specialization);
7970 // Turn the given function declaration into a function template
7971 // specialization, with the template arguments from the previous
7973 // Take copies of (semantic and syntactic) template argument lists.
7974 const TemplateArgumentList* TemplArgs = new (Context)
7975 TemplateArgumentList(Specialization->getTemplateSpecializationArgs());
7976 FD->setFunctionTemplateSpecialization(
7977 Specialization->getPrimaryTemplate(), TemplArgs, /*InsertPos=*/nullptr,
7978 SpecInfo->getTemplateSpecializationKind(),
7979 ExplicitTemplateArgs ? &ConvertedTemplateArgs[Specialization] : nullptr);
7981 // A function template specialization inherits the target attributes
7982 // of its template. (We require the attributes explicitly in the
7983 // code to match, but a template may have implicit attributes by
7984 // virtue e.g. of being constexpr, and it passes these implicit
7985 // attributes on to its specializations.)
7987 inheritCUDATargetAttrs(FD, *Specialization->getPrimaryTemplate());
7989 // The "previous declaration" for this function template specialization is
7990 // the prior function template specialization.
7992 Previous.addDecl(Specialization);
7996 /// \brief Perform semantic analysis for the given non-template member
7999 /// This routine performs all of the semantic analysis required for an
8000 /// explicit member function specialization. On successful completion,
8001 /// the function declaration \p FD will become a member function
8004 /// \param Member the member declaration, which will be updated to become a
8007 /// \param Previous the set of declarations, one of which may be specialized
8008 /// by this function specialization; the set will be modified to contain the
8009 /// redeclared member.
8011 Sema::CheckMemberSpecialization(NamedDecl *Member, LookupResult &Previous) {
8012 assert(!isa<TemplateDecl>(Member) && "Only for non-template members");
8014 // Try to find the member we are instantiating.
8015 NamedDecl *FoundInstantiation = nullptr;
8016 NamedDecl *Instantiation = nullptr;
8017 NamedDecl *InstantiatedFrom = nullptr;
8018 MemberSpecializationInfo *MSInfo = nullptr;
8020 if (Previous.empty()) {
8021 // Nowhere to look anyway.
8022 } else if (FunctionDecl *Function = dyn_cast<FunctionDecl>(Member)) {
8023 for (LookupResult::iterator I = Previous.begin(), E = Previous.end();
8025 NamedDecl *D = (*I)->getUnderlyingDecl();
8026 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(D)) {
8027 QualType Adjusted = Function->getType();
8028 if (!hasExplicitCallingConv(Adjusted))
8029 Adjusted = adjustCCAndNoReturn(Adjusted, Method->getType());
8030 if (Context.hasSameType(Adjusted, Method->getType())) {
8031 FoundInstantiation = *I;
8032 Instantiation = Method;
8033 InstantiatedFrom = Method->getInstantiatedFromMemberFunction();
8034 MSInfo = Method->getMemberSpecializationInfo();
8039 } else if (isa<VarDecl>(Member)) {
8041 if (Previous.isSingleResult() &&
8042 (PrevVar = dyn_cast<VarDecl>(Previous.getFoundDecl())))
8043 if (PrevVar->isStaticDataMember()) {
8044 FoundInstantiation = Previous.getRepresentativeDecl();
8045 Instantiation = PrevVar;
8046 InstantiatedFrom = PrevVar->getInstantiatedFromStaticDataMember();
8047 MSInfo = PrevVar->getMemberSpecializationInfo();
8049 } else if (isa<RecordDecl>(Member)) {
8050 CXXRecordDecl *PrevRecord;
8051 if (Previous.isSingleResult() &&
8052 (PrevRecord = dyn_cast<CXXRecordDecl>(Previous.getFoundDecl()))) {
8053 FoundInstantiation = Previous.getRepresentativeDecl();
8054 Instantiation = PrevRecord;
8055 InstantiatedFrom = PrevRecord->getInstantiatedFromMemberClass();
8056 MSInfo = PrevRecord->getMemberSpecializationInfo();
8058 } else if (isa<EnumDecl>(Member)) {
8060 if (Previous.isSingleResult() &&
8061 (PrevEnum = dyn_cast<EnumDecl>(Previous.getFoundDecl()))) {
8062 FoundInstantiation = Previous.getRepresentativeDecl();
8063 Instantiation = PrevEnum;
8064 InstantiatedFrom = PrevEnum->getInstantiatedFromMemberEnum();
8065 MSInfo = PrevEnum->getMemberSpecializationInfo();
8069 if (!Instantiation) {
8070 // There is no previous declaration that matches. Since member
8071 // specializations are always out-of-line, the caller will complain about
8072 // this mismatch later.
8076 // A member specialization in a friend declaration isn't really declaring
8077 // an explicit specialization, just identifying a specific (possibly implicit)
8078 // specialization. Don't change the template specialization kind.
8080 // FIXME: Is this really valid? Other compilers reject.
8081 if (Member->getFriendObjectKind() != Decl::FOK_None) {
8082 // Preserve instantiation information.
8083 if (InstantiatedFrom && isa<CXXMethodDecl>(Member)) {
8084 cast<CXXMethodDecl>(Member)->setInstantiationOfMemberFunction(
8085 cast<CXXMethodDecl>(InstantiatedFrom),
8086 cast<CXXMethodDecl>(Instantiation)->getTemplateSpecializationKind());
8087 } else if (InstantiatedFrom && isa<CXXRecordDecl>(Member)) {
8088 cast<CXXRecordDecl>(Member)->setInstantiationOfMemberClass(
8089 cast<CXXRecordDecl>(InstantiatedFrom),
8090 cast<CXXRecordDecl>(Instantiation)->getTemplateSpecializationKind());
8094 Previous.addDecl(FoundInstantiation);
8098 // Make sure that this is a specialization of a member.
8099 if (!InstantiatedFrom) {
8100 Diag(Member->getLocation(), diag::err_spec_member_not_instantiated)
8102 Diag(Instantiation->getLocation(), diag::note_specialized_decl);
8106 // C++ [temp.expl.spec]p6:
8107 // If a template, a member template or the member of a class template is
8108 // explicitly specialized then that specialization shall be declared
8109 // before the first use of that specialization that would cause an implicit
8110 // instantiation to take place, in every translation unit in which such a
8111 // use occurs; no diagnostic is required.
8112 assert(MSInfo && "Member specialization info missing?");
8114 bool HasNoEffect = false;
8115 if (CheckSpecializationInstantiationRedecl(Member->getLocation(),
8116 TSK_ExplicitSpecialization,
8118 MSInfo->getTemplateSpecializationKind(),
8119 MSInfo->getPointOfInstantiation(),
8123 // Check the scope of this explicit specialization.
8124 if (CheckTemplateSpecializationScope(*this,
8126 Instantiation, Member->getLocation(),
8130 // Note that this member specialization is an "instantiation of" the
8131 // corresponding member of the original template.
8132 if (auto *MemberFunction = dyn_cast<FunctionDecl>(Member)) {
8133 FunctionDecl *InstantiationFunction = cast<FunctionDecl>(Instantiation);
8134 if (InstantiationFunction->getTemplateSpecializationKind() ==
8135 TSK_ImplicitInstantiation) {
8136 // Explicit specializations of member functions of class templates do not
8137 // inherit '=delete' from the member function they are specializing.
8138 if (InstantiationFunction->isDeleted()) {
8139 // FIXME: This assert will not hold in the presence of modules.
8140 assert(InstantiationFunction->getCanonicalDecl() ==
8141 InstantiationFunction);
8142 // FIXME: We need an update record for this AST mutation.
8143 InstantiationFunction->setDeletedAsWritten(false);
8147 MemberFunction->setInstantiationOfMemberFunction(
8148 cast<CXXMethodDecl>(InstantiatedFrom), TSK_ExplicitSpecialization);
8149 } else if (auto *MemberVar = dyn_cast<VarDecl>(Member)) {
8150 MemberVar->setInstantiationOfStaticDataMember(
8151 cast<VarDecl>(InstantiatedFrom), TSK_ExplicitSpecialization);
8152 } else if (auto *MemberClass = dyn_cast<CXXRecordDecl>(Member)) {
8153 MemberClass->setInstantiationOfMemberClass(
8154 cast<CXXRecordDecl>(InstantiatedFrom), TSK_ExplicitSpecialization);
8155 } else if (auto *MemberEnum = dyn_cast<EnumDecl>(Member)) {
8156 MemberEnum->setInstantiationOfMemberEnum(
8157 cast<EnumDecl>(InstantiatedFrom), TSK_ExplicitSpecialization);
8159 llvm_unreachable("unknown member specialization kind");
8162 // Save the caller the trouble of having to figure out which declaration
8163 // this specialization matches.
8165 Previous.addDecl(FoundInstantiation);
8169 /// Complete the explicit specialization of a member of a class template by
8170 /// updating the instantiated member to be marked as an explicit specialization.
8172 /// \param OrigD The member declaration instantiated from the template.
8173 /// \param Loc The location of the explicit specialization of the member.
8174 template<typename DeclT>
8175 static void completeMemberSpecializationImpl(Sema &S, DeclT *OrigD,
8176 SourceLocation Loc) {
8177 if (OrigD->getTemplateSpecializationKind() != TSK_ImplicitInstantiation)
8180 // FIXME: Inform AST mutation listeners of this AST mutation.
8181 // FIXME: If there are multiple in-class declarations of the member (from
8182 // multiple modules, or a declaration and later definition of a member type),
8183 // should we update all of them?
8184 OrigD->setTemplateSpecializationKind(TSK_ExplicitSpecialization);
8185 OrigD->setLocation(Loc);
8188 void Sema::CompleteMemberSpecialization(NamedDecl *Member,
8189 LookupResult &Previous) {
8190 NamedDecl *Instantiation = cast<NamedDecl>(Member->getCanonicalDecl());
8191 if (Instantiation == Member)
8194 if (auto *Function = dyn_cast<CXXMethodDecl>(Instantiation))
8195 completeMemberSpecializationImpl(*this, Function, Member->getLocation());
8196 else if (auto *Var = dyn_cast<VarDecl>(Instantiation))
8197 completeMemberSpecializationImpl(*this, Var, Member->getLocation());
8198 else if (auto *Record = dyn_cast<CXXRecordDecl>(Instantiation))
8199 completeMemberSpecializationImpl(*this, Record, Member->getLocation());
8200 else if (auto *Enum = dyn_cast<EnumDecl>(Instantiation))
8201 completeMemberSpecializationImpl(*this, Enum, Member->getLocation());
8203 llvm_unreachable("unknown member specialization kind");
8206 /// \brief Check the scope of an explicit instantiation.
8208 /// \returns true if a serious error occurs, false otherwise.
8209 static bool CheckExplicitInstantiationScope(Sema &S, NamedDecl *D,
8210 SourceLocation InstLoc,
8211 bool WasQualifiedName) {
8212 DeclContext *OrigContext= D->getDeclContext()->getEnclosingNamespaceContext();
8213 DeclContext *CurContext = S.CurContext->getRedeclContext();
8215 if (CurContext->isRecord()) {
8216 S.Diag(InstLoc, diag::err_explicit_instantiation_in_class)
8221 // C++11 [temp.explicit]p3:
8222 // An explicit instantiation shall appear in an enclosing namespace of its
8223 // template. If the name declared in the explicit instantiation is an
8224 // unqualified name, the explicit instantiation shall appear in the
8225 // namespace where its template is declared or, if that namespace is inline
8226 // (7.3.1), any namespace from its enclosing namespace set.
8228 // This is DR275, which we do not retroactively apply to C++98/03.
8229 if (WasQualifiedName) {
8230 if (CurContext->Encloses(OrigContext))
8233 if (CurContext->InEnclosingNamespaceSetOf(OrigContext))
8237 if (NamespaceDecl *NS = dyn_cast<NamespaceDecl>(OrigContext)) {
8238 if (WasQualifiedName)
8240 S.getLangOpts().CPlusPlus11?
8241 diag::err_explicit_instantiation_out_of_scope :
8242 diag::warn_explicit_instantiation_out_of_scope_0x)
8246 S.getLangOpts().CPlusPlus11?
8247 diag::err_explicit_instantiation_unqualified_wrong_namespace :
8248 diag::warn_explicit_instantiation_unqualified_wrong_namespace_0x)
8252 S.getLangOpts().CPlusPlus11?
8253 diag::err_explicit_instantiation_must_be_global :
8254 diag::warn_explicit_instantiation_must_be_global_0x)
8256 S.Diag(D->getLocation(), diag::note_explicit_instantiation_here);
8260 /// \brief Determine whether the given scope specifier has a template-id in it.
8261 static bool ScopeSpecifierHasTemplateId(const CXXScopeSpec &SS) {
8265 // C++11 [temp.explicit]p3:
8266 // If the explicit instantiation is for a member function, a member class
8267 // or a static data member of a class template specialization, the name of
8268 // the class template specialization in the qualified-id for the member
8269 // name shall be a simple-template-id.
8271 // C++98 has the same restriction, just worded differently.
8272 for (NestedNameSpecifier *NNS = SS.getScopeRep(); NNS;
8273 NNS = NNS->getPrefix())
8274 if (const Type *T = NNS->getAsType())
8275 if (isa<TemplateSpecializationType>(T))
8281 /// Make a dllexport or dllimport attr on a class template specialization take
8283 static void dllExportImportClassTemplateSpecialization(
8284 Sema &S, ClassTemplateSpecializationDecl *Def) {
8285 auto *A = cast_or_null<InheritableAttr>(getDLLAttr(Def));
8286 assert(A && "dllExportImportClassTemplateSpecialization called "
8287 "on Def without dllexport or dllimport");
8289 // We reject explicit instantiations in class scope, so there should
8290 // never be any delayed exported classes to worry about.
8291 assert(S.DelayedDllExportClasses.empty() &&
8292 "delayed exports present at explicit instantiation");
8293 S.checkClassLevelDLLAttribute(Def);
8295 // Propagate attribute to base class templates.
8296 for (auto &B : Def->bases()) {
8297 if (auto *BT = dyn_cast_or_null<ClassTemplateSpecializationDecl>(
8298 B.getType()->getAsCXXRecordDecl()))
8299 S.propagateDLLAttrToBaseClassTemplate(Def, A, BT, B.getLocStart());
8302 S.referenceDLLExportedClassMethods();
8305 // Explicit instantiation of a class template specialization
8307 Sema::ActOnExplicitInstantiation(Scope *S,
8308 SourceLocation ExternLoc,
8309 SourceLocation TemplateLoc,
8311 SourceLocation KWLoc,
8312 const CXXScopeSpec &SS,
8313 TemplateTy TemplateD,
8314 SourceLocation TemplateNameLoc,
8315 SourceLocation LAngleLoc,
8316 ASTTemplateArgsPtr TemplateArgsIn,
8317 SourceLocation RAngleLoc,
8318 AttributeList *Attr) {
8319 // Find the class template we're specializing
8320 TemplateName Name = TemplateD.get();
8321 TemplateDecl *TD = Name.getAsTemplateDecl();
8322 // Check that the specialization uses the same tag kind as the
8323 // original template.
8324 TagTypeKind Kind = TypeWithKeyword::getTagTypeKindForTypeSpec(TagSpec);
8325 assert(Kind != TTK_Enum &&
8326 "Invalid enum tag in class template explicit instantiation!");
8328 ClassTemplateDecl *ClassTemplate = dyn_cast<ClassTemplateDecl>(TD);
8330 if (!ClassTemplate) {
8331 NonTagKind NTK = getNonTagTypeDeclKind(TD, Kind);
8332 Diag(TemplateNameLoc, diag::err_tag_reference_non_tag) << TD << NTK << Kind;
8333 Diag(TD->getLocation(), diag::note_previous_use);
8337 if (!isAcceptableTagRedeclaration(ClassTemplate->getTemplatedDecl(),
8338 Kind, /*isDefinition*/false, KWLoc,
8339 ClassTemplate->getIdentifier())) {
8340 Diag(KWLoc, diag::err_use_with_wrong_tag)
8342 << FixItHint::CreateReplacement(KWLoc,
8343 ClassTemplate->getTemplatedDecl()->getKindName());
8344 Diag(ClassTemplate->getTemplatedDecl()->getLocation(),
8345 diag::note_previous_use);
8346 Kind = ClassTemplate->getTemplatedDecl()->getTagKind();
8349 // C++0x [temp.explicit]p2:
8350 // There are two forms of explicit instantiation: an explicit instantiation
8351 // definition and an explicit instantiation declaration. An explicit
8352 // instantiation declaration begins with the extern keyword. [...]
8353 TemplateSpecializationKind TSK = ExternLoc.isInvalid()
8354 ? TSK_ExplicitInstantiationDefinition
8355 : TSK_ExplicitInstantiationDeclaration;
8357 if (TSK == TSK_ExplicitInstantiationDeclaration) {
8358 // Check for dllexport class template instantiation declarations.
8359 for (AttributeList *A = Attr; A; A = A->getNext()) {
8360 if (A->getKind() == AttributeList::AT_DLLExport) {
8362 diag::warn_attribute_dllexport_explicit_instantiation_decl);
8363 Diag(A->getLoc(), diag::note_attribute);
8368 if (auto *A = ClassTemplate->getTemplatedDecl()->getAttr<DLLExportAttr>()) {
8370 diag::warn_attribute_dllexport_explicit_instantiation_decl);
8371 Diag(A->getLocation(), diag::note_attribute);
8375 // In MSVC mode, dllimported explicit instantiation definitions are treated as
8376 // instantiation declarations for most purposes.
8377 bool DLLImportExplicitInstantiationDef = false;
8378 if (TSK == TSK_ExplicitInstantiationDefinition &&
8379 Context.getTargetInfo().getCXXABI().isMicrosoft()) {
8380 // Check for dllimport class template instantiation definitions.
8382 ClassTemplate->getTemplatedDecl()->getAttr<DLLImportAttr>();
8383 for (AttributeList *A = Attr; A; A = A->getNext()) {
8384 if (A->getKind() == AttributeList::AT_DLLImport)
8386 if (A->getKind() == AttributeList::AT_DLLExport) {
8387 // dllexport trumps dllimport here.
8393 TSK = TSK_ExplicitInstantiationDeclaration;
8394 DLLImportExplicitInstantiationDef = true;
8398 // Translate the parser's template argument list in our AST format.
8399 TemplateArgumentListInfo TemplateArgs(LAngleLoc, RAngleLoc);
8400 translateTemplateArguments(TemplateArgsIn, TemplateArgs);
8402 // Check that the template argument list is well-formed for this
8404 SmallVector<TemplateArgument, 4> Converted;
8405 if (CheckTemplateArgumentList(ClassTemplate, TemplateNameLoc,
8406 TemplateArgs, false, Converted))
8409 // Find the class template specialization declaration that
8410 // corresponds to these arguments.
8411 void *InsertPos = nullptr;
8412 ClassTemplateSpecializationDecl *PrevDecl
8413 = ClassTemplate->findSpecialization(Converted, InsertPos);
8415 TemplateSpecializationKind PrevDecl_TSK
8416 = PrevDecl ? PrevDecl->getTemplateSpecializationKind() : TSK_Undeclared;
8418 // C++0x [temp.explicit]p2:
8419 // [...] An explicit instantiation shall appear in an enclosing
8420 // namespace of its template. [...]
8422 // This is C++ DR 275.
8423 if (CheckExplicitInstantiationScope(*this, ClassTemplate, TemplateNameLoc,
8427 ClassTemplateSpecializationDecl *Specialization = nullptr;
8429 bool HasNoEffect = false;
8431 if (CheckSpecializationInstantiationRedecl(TemplateNameLoc, TSK,
8432 PrevDecl, PrevDecl_TSK,
8433 PrevDecl->getPointOfInstantiation(),
8437 // Even though HasNoEffect == true means that this explicit instantiation
8438 // has no effect on semantics, we go on to put its syntax in the AST.
8440 if (PrevDecl_TSK == TSK_ImplicitInstantiation ||
8441 PrevDecl_TSK == TSK_Undeclared) {
8442 // Since the only prior class template specialization with these
8443 // arguments was referenced but not declared, reuse that
8444 // declaration node as our own, updating the source location
8445 // for the template name to reflect our new declaration.
8446 // (Other source locations will be updated later.)
8447 Specialization = PrevDecl;
8448 Specialization->setLocation(TemplateNameLoc);
8452 if (PrevDecl_TSK == TSK_ExplicitInstantiationDeclaration &&
8453 DLLImportExplicitInstantiationDef) {
8454 // The new specialization might add a dllimport attribute.
8455 HasNoEffect = false;
8459 if (!Specialization) {
8460 // Create a new class template specialization declaration node for
8461 // this explicit specialization.
8463 = ClassTemplateSpecializationDecl::Create(Context, Kind,
8464 ClassTemplate->getDeclContext(),
8465 KWLoc, TemplateNameLoc,
8469 SetNestedNameSpecifier(Specialization, SS);
8471 if (!HasNoEffect && !PrevDecl) {
8472 // Insert the new specialization.
8473 ClassTemplate->AddSpecialization(Specialization, InsertPos);
8477 // Build the fully-sugared type for this explicit instantiation as
8478 // the user wrote in the explicit instantiation itself. This means
8479 // that we'll pretty-print the type retrieved from the
8480 // specialization's declaration the way that the user actually wrote
8481 // the explicit instantiation, rather than formatting the name based
8482 // on the "canonical" representation used to store the template
8483 // arguments in the specialization.
8484 TypeSourceInfo *WrittenTy
8485 = Context.getTemplateSpecializationTypeInfo(Name, TemplateNameLoc,
8487 Context.getTypeDeclType(Specialization));
8488 Specialization->setTypeAsWritten(WrittenTy);
8490 // Set source locations for keywords.
8491 Specialization->setExternLoc(ExternLoc);
8492 Specialization->setTemplateKeywordLoc(TemplateLoc);
8493 Specialization->setBraceRange(SourceRange());
8495 bool PreviouslyDLLExported = Specialization->hasAttr<DLLExportAttr>();
8497 ProcessDeclAttributeList(S, Specialization, Attr);
8499 // Add the explicit instantiation into its lexical context. However,
8500 // since explicit instantiations are never found by name lookup, we
8501 // just put it into the declaration context directly.
8502 Specialization->setLexicalDeclContext(CurContext);
8503 CurContext->addDecl(Specialization);
8505 // Syntax is now OK, so return if it has no other effect on semantics.
8507 // Set the template specialization kind.
8508 Specialization->setTemplateSpecializationKind(TSK);
8509 return Specialization;
8512 // C++ [temp.explicit]p3:
8513 // A definition of a class template or class member template
8514 // shall be in scope at the point of the explicit instantiation of
8515 // the class template or class member template.
8517 // This check comes when we actually try to perform the
8519 ClassTemplateSpecializationDecl *Def
8520 = cast_or_null<ClassTemplateSpecializationDecl>(
8521 Specialization->getDefinition());
8523 InstantiateClassTemplateSpecialization(TemplateNameLoc, Specialization, TSK);
8524 else if (TSK == TSK_ExplicitInstantiationDefinition) {
8525 MarkVTableUsed(TemplateNameLoc, Specialization, true);
8526 Specialization->setPointOfInstantiation(Def->getPointOfInstantiation());
8529 // Instantiate the members of this class template specialization.
8530 Def = cast_or_null<ClassTemplateSpecializationDecl>(
8531 Specialization->getDefinition());
8533 TemplateSpecializationKind Old_TSK = Def->getTemplateSpecializationKind();
8534 // Fix a TSK_ExplicitInstantiationDeclaration followed by a
8535 // TSK_ExplicitInstantiationDefinition
8536 if (Old_TSK == TSK_ExplicitInstantiationDeclaration &&
8537 (TSK == TSK_ExplicitInstantiationDefinition ||
8538 DLLImportExplicitInstantiationDef)) {
8539 // FIXME: Need to notify the ASTMutationListener that we did this.
8540 Def->setTemplateSpecializationKind(TSK);
8542 if (!getDLLAttr(Def) && getDLLAttr(Specialization) &&
8543 (Context.getTargetInfo().getCXXABI().isMicrosoft() ||
8544 Context.getTargetInfo().getTriple().isWindowsItaniumEnvironment())) {
8545 // In the MS ABI, an explicit instantiation definition can add a dll
8546 // attribute to a template with a previous instantiation declaration.
8547 // MinGW doesn't allow this.
8548 auto *A = cast<InheritableAttr>(
8549 getDLLAttr(Specialization)->clone(getASTContext()));
8550 A->setInherited(true);
8552 dllExportImportClassTemplateSpecialization(*this, Def);
8556 // Fix a TSK_ImplicitInstantiation followed by a
8557 // TSK_ExplicitInstantiationDefinition
8558 bool NewlyDLLExported =
8559 !PreviouslyDLLExported && Specialization->hasAttr<DLLExportAttr>();
8560 if (Old_TSK == TSK_ImplicitInstantiation && NewlyDLLExported &&
8561 (Context.getTargetInfo().getCXXABI().isMicrosoft() ||
8562 Context.getTargetInfo().getTriple().isWindowsItaniumEnvironment())) {
8563 // In the MS ABI, an explicit instantiation definition can add a dll
8564 // attribute to a template with a previous implicit instantiation.
8565 // MinGW doesn't allow this. We limit clang to only adding dllexport, to
8566 // avoid potentially strange codegen behavior. For example, if we extend
8567 // this conditional to dllimport, and we have a source file calling a
8568 // method on an implicitly instantiated template class instance and then
8569 // declaring a dllimport explicit instantiation definition for the same
8570 // template class, the codegen for the method call will not respect the
8571 // dllimport, while it will with cl. The Def will already have the DLL
8572 // attribute, since the Def and Specialization will be the same in the
8573 // case of Old_TSK == TSK_ImplicitInstantiation, and we already added the
8574 // attribute to the Specialization; we just need to make it take effect.
8575 assert(Def == Specialization &&
8576 "Def and Specialization should match for implicit instantiation");
8577 dllExportImportClassTemplateSpecialization(*this, Def);
8580 // Set the template specialization kind. Make sure it is set before
8581 // instantiating the members which will trigger ASTConsumer callbacks.
8582 Specialization->setTemplateSpecializationKind(TSK);
8583 InstantiateClassTemplateSpecializationMembers(TemplateNameLoc, Def, TSK);
8586 // Set the template specialization kind.
8587 Specialization->setTemplateSpecializationKind(TSK);
8590 return Specialization;
8593 // Explicit instantiation of a member class of a class template.
8595 Sema::ActOnExplicitInstantiation(Scope *S,
8596 SourceLocation ExternLoc,
8597 SourceLocation TemplateLoc,
8599 SourceLocation KWLoc,
8601 IdentifierInfo *Name,
8602 SourceLocation NameLoc,
8603 AttributeList *Attr) {
8606 bool IsDependent = false;
8607 Decl *TagD = ActOnTag(S, TagSpec, Sema::TUK_Reference,
8608 KWLoc, SS, Name, NameLoc, Attr, AS_none,
8609 /*ModulePrivateLoc=*/SourceLocation(),
8610 MultiTemplateParamsArg(), Owned, IsDependent,
8611 SourceLocation(), false, TypeResult(),
8612 /*IsTypeSpecifier*/false);
8613 assert(!IsDependent && "explicit instantiation of dependent name not yet handled");
8618 TagDecl *Tag = cast<TagDecl>(TagD);
8619 assert(!Tag->isEnum() && "shouldn't see enumerations here");
8621 if (Tag->isInvalidDecl())
8624 CXXRecordDecl *Record = cast<CXXRecordDecl>(Tag);
8625 CXXRecordDecl *Pattern = Record->getInstantiatedFromMemberClass();
8627 Diag(TemplateLoc, diag::err_explicit_instantiation_nontemplate_type)
8628 << Context.getTypeDeclType(Record);
8629 Diag(Record->getLocation(), diag::note_nontemplate_decl_here);
8633 // C++0x [temp.explicit]p2:
8634 // If the explicit instantiation is for a class or member class, the
8635 // elaborated-type-specifier in the declaration shall include a
8636 // simple-template-id.
8638 // C++98 has the same restriction, just worded differently.
8639 if (!ScopeSpecifierHasTemplateId(SS))
8640 Diag(TemplateLoc, diag::ext_explicit_instantiation_without_qualified_id)
8641 << Record << SS.getRange();
8643 // C++0x [temp.explicit]p2:
8644 // There are two forms of explicit instantiation: an explicit instantiation
8645 // definition and an explicit instantiation declaration. An explicit
8646 // instantiation declaration begins with the extern keyword. [...]
8647 TemplateSpecializationKind TSK
8648 = ExternLoc.isInvalid()? TSK_ExplicitInstantiationDefinition
8649 : TSK_ExplicitInstantiationDeclaration;
8651 // C++0x [temp.explicit]p2:
8652 // [...] An explicit instantiation shall appear in an enclosing
8653 // namespace of its template. [...]
8655 // This is C++ DR 275.
8656 CheckExplicitInstantiationScope(*this, Record, NameLoc, true);
8658 // Verify that it is okay to explicitly instantiate here.
8659 CXXRecordDecl *PrevDecl
8660 = cast_or_null<CXXRecordDecl>(Record->getPreviousDecl());
8661 if (!PrevDecl && Record->getDefinition())
8664 MemberSpecializationInfo *MSInfo = PrevDecl->getMemberSpecializationInfo();
8665 bool HasNoEffect = false;
8666 assert(MSInfo && "No member specialization information?");
8667 if (CheckSpecializationInstantiationRedecl(TemplateLoc, TSK,
8669 MSInfo->getTemplateSpecializationKind(),
8670 MSInfo->getPointOfInstantiation(),
8677 CXXRecordDecl *RecordDef
8678 = cast_or_null<CXXRecordDecl>(Record->getDefinition());
8680 // C++ [temp.explicit]p3:
8681 // A definition of a member class of a class template shall be in scope
8682 // at the point of an explicit instantiation of the member class.
8684 = cast_or_null<CXXRecordDecl>(Pattern->getDefinition());
8686 Diag(TemplateLoc, diag::err_explicit_instantiation_undefined_member)
8687 << 0 << Record->getDeclName() << Record->getDeclContext();
8688 Diag(Pattern->getLocation(), diag::note_forward_declaration)
8692 if (InstantiateClass(NameLoc, Record, Def,
8693 getTemplateInstantiationArgs(Record),
8697 RecordDef = cast_or_null<CXXRecordDecl>(Record->getDefinition());
8703 // Instantiate all of the members of the class.
8704 InstantiateClassMembers(NameLoc, RecordDef,
8705 getTemplateInstantiationArgs(Record), TSK);
8707 if (TSK == TSK_ExplicitInstantiationDefinition)
8708 MarkVTableUsed(NameLoc, RecordDef, true);
8710 // FIXME: We don't have any representation for explicit instantiations of
8711 // member classes. Such a representation is not needed for compilation, but it
8712 // should be available for clients that want to see all of the declarations in
8717 DeclResult Sema::ActOnExplicitInstantiation(Scope *S,
8718 SourceLocation ExternLoc,
8719 SourceLocation TemplateLoc,
8721 // Explicit instantiations always require a name.
8722 // TODO: check if/when DNInfo should replace Name.
8723 DeclarationNameInfo NameInfo = GetNameForDeclarator(D);
8724 DeclarationName Name = NameInfo.getName();
8726 if (!D.isInvalidType())
8727 Diag(D.getDeclSpec().getLocStart(),
8728 diag::err_explicit_instantiation_requires_name)
8729 << D.getDeclSpec().getSourceRange()
8730 << D.getSourceRange();
8735 // The scope passed in may not be a decl scope. Zip up the scope tree until
8736 // we find one that is.
8737 while ((S->getFlags() & Scope::DeclScope) == 0 ||
8738 (S->getFlags() & Scope::TemplateParamScope) != 0)
8741 // Determine the type of the declaration.
8742 TypeSourceInfo *T = GetTypeForDeclarator(D, S);
8743 QualType R = T->getType();
8748 // A storage-class-specifier shall not be specified in [...] an explicit
8749 // instantiation (14.7.2) directive.
8750 if (D.getDeclSpec().getStorageClassSpec() == DeclSpec::SCS_typedef) {
8751 Diag(D.getIdentifierLoc(), diag::err_explicit_instantiation_of_typedef)
8754 } else if (D.getDeclSpec().getStorageClassSpec()
8755 != DeclSpec::SCS_unspecified) {
8756 // Complain about then remove the storage class specifier.
8757 Diag(D.getIdentifierLoc(), diag::err_explicit_instantiation_storage_class)
8758 << FixItHint::CreateRemoval(D.getDeclSpec().getStorageClassSpecLoc());
8760 D.getMutableDeclSpec().ClearStorageClassSpecs();
8763 // C++0x [temp.explicit]p1:
8764 // [...] An explicit instantiation of a function template shall not use the
8765 // inline or constexpr specifiers.
8766 // Presumably, this also applies to member functions of class templates as
8768 if (D.getDeclSpec().isInlineSpecified())
8769 Diag(D.getDeclSpec().getInlineSpecLoc(),
8770 getLangOpts().CPlusPlus11 ?
8771 diag::err_explicit_instantiation_inline :
8772 diag::warn_explicit_instantiation_inline_0x)
8773 << FixItHint::CreateRemoval(D.getDeclSpec().getInlineSpecLoc());
8774 if (D.getDeclSpec().isConstexprSpecified() && R->isFunctionType())
8775 // FIXME: Add a fix-it to remove the 'constexpr' and add a 'const' if one is
8776 // not already specified.
8777 Diag(D.getDeclSpec().getConstexprSpecLoc(),
8778 diag::err_explicit_instantiation_constexpr);
8780 // C++ Concepts TS [dcl.spec.concept]p1: The concept specifier shall be
8781 // applied only to the definition of a function template or variable template,
8782 // declared in namespace scope.
8783 if (D.getDeclSpec().isConceptSpecified()) {
8784 Diag(D.getDeclSpec().getConceptSpecLoc(),
8785 diag::err_concept_specified_specialization) << 0;
8789 // A deduction guide is not on the list of entities that can be explicitly
8791 if (Name.getNameKind() == DeclarationName::CXXDeductionGuideName) {
8792 Diag(D.getDeclSpec().getLocStart(), diag::err_deduction_guide_specialized)
8793 << /*explicit instantiation*/ 0;
8797 // C++0x [temp.explicit]p2:
8798 // There are two forms of explicit instantiation: an explicit instantiation
8799 // definition and an explicit instantiation declaration. An explicit
8800 // instantiation declaration begins with the extern keyword. [...]
8801 TemplateSpecializationKind TSK
8802 = ExternLoc.isInvalid()? TSK_ExplicitInstantiationDefinition
8803 : TSK_ExplicitInstantiationDeclaration;
8805 LookupResult Previous(*this, NameInfo, LookupOrdinaryName);
8806 LookupParsedName(Previous, S, &D.getCXXScopeSpec());
8808 if (!R->isFunctionType()) {
8809 // C++ [temp.explicit]p1:
8810 // A [...] static data member of a class template can be explicitly
8811 // instantiated from the member definition associated with its class
8813 // C++1y [temp.explicit]p1:
8814 // A [...] variable [...] template specialization can be explicitly
8815 // instantiated from its template.
8816 if (Previous.isAmbiguous())
8819 VarDecl *Prev = Previous.getAsSingle<VarDecl>();
8820 VarTemplateDecl *PrevTemplate = Previous.getAsSingle<VarTemplateDecl>();
8822 if (!PrevTemplate) {
8823 if (!Prev || !Prev->isStaticDataMember()) {
8824 // We expect to see a data data member here.
8825 Diag(D.getIdentifierLoc(), diag::err_explicit_instantiation_not_known)
8827 for (LookupResult::iterator P = Previous.begin(), PEnd = Previous.end();
8829 Diag((*P)->getLocation(), diag::note_explicit_instantiation_here);
8833 if (!Prev->getInstantiatedFromStaticDataMember()) {
8834 // FIXME: Check for explicit specialization?
8835 Diag(D.getIdentifierLoc(),
8836 diag::err_explicit_instantiation_data_member_not_instantiated)
8838 Diag(Prev->getLocation(), diag::note_explicit_instantiation_here);
8839 // FIXME: Can we provide a note showing where this was declared?
8843 // Explicitly instantiate a variable template.
8845 // C++1y [dcl.spec.auto]p6:
8846 // ... A program that uses auto or decltype(auto) in a context not
8847 // explicitly allowed in this section is ill-formed.
8849 // This includes auto-typed variable template instantiations.
8850 if (R->isUndeducedType()) {
8851 Diag(T->getTypeLoc().getLocStart(),
8852 diag::err_auto_not_allowed_var_inst);
8856 if (D.getName().getKind() != UnqualifiedId::IK_TemplateId) {
8857 // C++1y [temp.explicit]p3:
8858 // If the explicit instantiation is for a variable, the unqualified-id
8859 // in the declaration shall be a template-id.
8860 Diag(D.getIdentifierLoc(),
8861 diag::err_explicit_instantiation_without_template_id)
8863 Diag(PrevTemplate->getLocation(),
8864 diag::note_explicit_instantiation_here);
8868 // C++ Concepts TS [dcl.spec.concept]p7: A program shall not declare an
8869 // explicit instantiation (14.8.2) [...] of a concept definition.
8870 if (PrevTemplate->isConcept()) {
8871 Diag(D.getIdentifierLoc(), diag::err_concept_specialized)
8872 << 1 /*variable*/ << 0 /*explicitly instantiated*/;
8873 Diag(PrevTemplate->getLocation(), diag::note_previous_declaration);
8877 // Translate the parser's template argument list into our AST format.
8878 TemplateArgumentListInfo TemplateArgs =
8879 makeTemplateArgumentListInfo(*this, *D.getName().TemplateId);
8881 DeclResult Res = CheckVarTemplateId(PrevTemplate, TemplateLoc,
8882 D.getIdentifierLoc(), TemplateArgs);
8883 if (Res.isInvalid())
8886 // Ignore access control bits, we don't need them for redeclaration
8888 Prev = cast<VarDecl>(Res.get());
8891 // C++0x [temp.explicit]p2:
8892 // If the explicit instantiation is for a member function, a member class
8893 // or a static data member of a class template specialization, the name of
8894 // the class template specialization in the qualified-id for the member
8895 // name shall be a simple-template-id.
8897 // C++98 has the same restriction, just worded differently.
8899 // This does not apply to variable template specializations, where the
8900 // template-id is in the unqualified-id instead.
8901 if (!ScopeSpecifierHasTemplateId(D.getCXXScopeSpec()) && !PrevTemplate)
8902 Diag(D.getIdentifierLoc(),
8903 diag::ext_explicit_instantiation_without_qualified_id)
8904 << Prev << D.getCXXScopeSpec().getRange();
8906 // Check the scope of this explicit instantiation.
8907 CheckExplicitInstantiationScope(*this, Prev, D.getIdentifierLoc(), true);
8909 // Verify that it is okay to explicitly instantiate here.
8910 TemplateSpecializationKind PrevTSK = Prev->getTemplateSpecializationKind();
8911 SourceLocation POI = Prev->getPointOfInstantiation();
8912 bool HasNoEffect = false;
8913 if (CheckSpecializationInstantiationRedecl(D.getIdentifierLoc(), TSK, Prev,
8914 PrevTSK, POI, HasNoEffect))
8918 // Instantiate static data member or variable template.
8920 Prev->setTemplateSpecializationKind(TSK, D.getIdentifierLoc());
8922 // Merge attributes.
8923 if (AttributeList *Attr = D.getDeclSpec().getAttributes().getList())
8924 ProcessDeclAttributeList(S, Prev, Attr);
8926 if (TSK == TSK_ExplicitInstantiationDefinition)
8927 InstantiateVariableDefinition(D.getIdentifierLoc(), Prev);
8930 // Check the new variable specialization against the parsed input.
8931 if (PrevTemplate && Prev && !Context.hasSameType(Prev->getType(), R)) {
8932 Diag(T->getTypeLoc().getLocStart(),
8933 diag::err_invalid_var_template_spec_type)
8934 << 0 << PrevTemplate << R << Prev->getType();
8935 Diag(PrevTemplate->getLocation(), diag::note_template_declared_here)
8936 << 2 << PrevTemplate->getDeclName();
8940 // FIXME: Create an ExplicitInstantiation node?
8941 return (Decl*) nullptr;
8944 // If the declarator is a template-id, translate the parser's template
8945 // argument list into our AST format.
8946 bool HasExplicitTemplateArgs = false;
8947 TemplateArgumentListInfo TemplateArgs;
8948 if (D.getName().getKind() == UnqualifiedId::IK_TemplateId) {
8949 TemplateArgs = makeTemplateArgumentListInfo(*this, *D.getName().TemplateId);
8950 HasExplicitTemplateArgs = true;
8953 // C++ [temp.explicit]p1:
8954 // A [...] function [...] can be explicitly instantiated from its template.
8955 // A member function [...] of a class template can be explicitly
8956 // instantiated from the member definition associated with its class
8958 UnresolvedSet<8> Matches;
8959 AttributeList *Attr = D.getDeclSpec().getAttributes().getList();
8960 TemplateSpecCandidateSet FailedCandidates(D.getIdentifierLoc());
8961 for (LookupResult::iterator P = Previous.begin(), PEnd = Previous.end();
8963 NamedDecl *Prev = *P;
8964 if (!HasExplicitTemplateArgs) {
8965 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Prev)) {
8966 QualType Adjusted = adjustCCAndNoReturn(R, Method->getType(),
8967 /*AdjustExceptionSpec*/true);
8968 if (Context.hasSameUnqualifiedType(Method->getType(), Adjusted)) {
8971 Matches.addDecl(Method, P.getAccess());
8972 if (Method->getTemplateSpecializationKind() == TSK_Undeclared)
8978 FunctionTemplateDecl *FunTmpl = dyn_cast<FunctionTemplateDecl>(Prev);
8982 TemplateDeductionInfo Info(FailedCandidates.getLocation());
8983 FunctionDecl *Specialization = nullptr;
8984 if (TemplateDeductionResult TDK
8985 = DeduceTemplateArguments(FunTmpl,
8986 (HasExplicitTemplateArgs ? &TemplateArgs
8988 R, Specialization, Info)) {
8989 // Keep track of almost-matches.
8990 FailedCandidates.addCandidate()
8991 .set(P.getPair(), FunTmpl->getTemplatedDecl(),
8992 MakeDeductionFailureInfo(Context, TDK, Info));
8997 // Target attributes are part of the cuda function signature, so
8998 // the cuda target of the instantiated function must match that of its
8999 // template. Given that C++ template deduction does not take
9000 // target attributes into account, we reject candidates here that
9001 // have a different target.
9002 if (LangOpts.CUDA &&
9003 IdentifyCUDATarget(Specialization,
9004 /* IgnoreImplicitHDAttributes = */ true) !=
9005 IdentifyCUDATarget(Attr)) {
9006 FailedCandidates.addCandidate().set(
9007 P.getPair(), FunTmpl->getTemplatedDecl(),
9008 MakeDeductionFailureInfo(Context, TDK_CUDATargetMismatch, Info));
9012 Matches.addDecl(Specialization, P.getAccess());
9015 // Find the most specialized function template specialization.
9016 UnresolvedSetIterator Result = getMostSpecialized(
9017 Matches.begin(), Matches.end(), FailedCandidates,
9018 D.getIdentifierLoc(),
9019 PDiag(diag::err_explicit_instantiation_not_known) << Name,
9020 PDiag(diag::err_explicit_instantiation_ambiguous) << Name,
9021 PDiag(diag::note_explicit_instantiation_candidate));
9023 if (Result == Matches.end())
9026 // Ignore access control bits, we don't need them for redeclaration checking.
9027 FunctionDecl *Specialization = cast<FunctionDecl>(*Result);
9029 // C++11 [except.spec]p4
9030 // In an explicit instantiation an exception-specification may be specified,
9031 // but is not required.
9032 // If an exception-specification is specified in an explicit instantiation
9033 // directive, it shall be compatible with the exception-specifications of
9034 // other declarations of that function.
9035 if (auto *FPT = R->getAs<FunctionProtoType>())
9036 if (FPT->hasExceptionSpec()) {
9038 diag::err_mismatched_exception_spec_explicit_instantiation;
9039 if (getLangOpts().MicrosoftExt)
9040 DiagID = diag::ext_mismatched_exception_spec_explicit_instantiation;
9041 bool Result = CheckEquivalentExceptionSpec(
9042 PDiag(DiagID) << Specialization->getType(),
9043 PDiag(diag::note_explicit_instantiation_here),
9044 Specialization->getType()->getAs<FunctionProtoType>(),
9045 Specialization->getLocation(), FPT, D.getLocStart());
9046 // In Microsoft mode, mismatching exception specifications just cause a
9048 if (!getLangOpts().MicrosoftExt && Result)
9052 if (Specialization->getTemplateSpecializationKind() == TSK_Undeclared) {
9053 Diag(D.getIdentifierLoc(),
9054 diag::err_explicit_instantiation_member_function_not_instantiated)
9056 << (Specialization->getTemplateSpecializationKind() ==
9057 TSK_ExplicitSpecialization);
9058 Diag(Specialization->getLocation(), diag::note_explicit_instantiation_here);
9062 FunctionDecl *PrevDecl = Specialization->getPreviousDecl();
9063 if (!PrevDecl && Specialization->isThisDeclarationADefinition())
9064 PrevDecl = Specialization;
9067 bool HasNoEffect = false;
9068 if (CheckSpecializationInstantiationRedecl(D.getIdentifierLoc(), TSK,
9070 PrevDecl->getTemplateSpecializationKind(),
9071 PrevDecl->getPointOfInstantiation(),
9075 // FIXME: We may still want to build some representation of this
9076 // explicit specialization.
9078 return (Decl*) nullptr;
9081 Specialization->setTemplateSpecializationKind(TSK, D.getIdentifierLoc());
9083 ProcessDeclAttributeList(S, Specialization, Attr);
9085 if (Specialization->isDefined()) {
9086 // Let the ASTConsumer know that this function has been explicitly
9087 // instantiated now, and its linkage might have changed.
9088 Consumer.HandleTopLevelDecl(DeclGroupRef(Specialization));
9089 } else if (TSK == TSK_ExplicitInstantiationDefinition)
9090 InstantiateFunctionDefinition(D.getIdentifierLoc(), Specialization);
9092 // C++0x [temp.explicit]p2:
9093 // If the explicit instantiation is for a member function, a member class
9094 // or a static data member of a class template specialization, the name of
9095 // the class template specialization in the qualified-id for the member
9096 // name shall be a simple-template-id.
9098 // C++98 has the same restriction, just worded differently.
9099 FunctionTemplateDecl *FunTmpl = Specialization->getPrimaryTemplate();
9100 if (D.getName().getKind() != UnqualifiedId::IK_TemplateId && !FunTmpl &&
9101 D.getCXXScopeSpec().isSet() &&
9102 !ScopeSpecifierHasTemplateId(D.getCXXScopeSpec()))
9103 Diag(D.getIdentifierLoc(),
9104 diag::ext_explicit_instantiation_without_qualified_id)
9105 << Specialization << D.getCXXScopeSpec().getRange();
9107 // C++ Concepts TS [dcl.spec.concept]p7: A program shall not declare an
9108 // explicit instantiation (14.8.2) [...] of a concept definition.
9109 if (FunTmpl && FunTmpl->isConcept() &&
9110 !D.getDeclSpec().isConceptSpecified()) {
9111 Diag(D.getIdentifierLoc(), diag::err_concept_specialized)
9112 << 0 /*function*/ << 0 /*explicitly instantiated*/;
9113 Diag(FunTmpl->getLocation(), diag::note_previous_declaration);
9117 CheckExplicitInstantiationScope(*this,
9118 FunTmpl? (NamedDecl *)FunTmpl
9119 : Specialization->getInstantiatedFromMemberFunction(),
9120 D.getIdentifierLoc(),
9121 D.getCXXScopeSpec().isSet());
9123 // FIXME: Create some kind of ExplicitInstantiationDecl here.
9124 return (Decl*) nullptr;
9128 Sema::ActOnDependentTag(Scope *S, unsigned TagSpec, TagUseKind TUK,
9129 const CXXScopeSpec &SS, IdentifierInfo *Name,
9130 SourceLocation TagLoc, SourceLocation NameLoc) {
9131 // This has to hold, because SS is expected to be defined.
9132 assert(Name && "Expected a name in a dependent tag");
9134 NestedNameSpecifier *NNS = SS.getScopeRep();
9138 TagTypeKind Kind = TypeWithKeyword::getTagTypeKindForTypeSpec(TagSpec);
9140 if (TUK == TUK_Declaration || TUK == TUK_Definition) {
9141 Diag(NameLoc, diag::err_dependent_tag_decl)
9142 << (TUK == TUK_Definition) << Kind << SS.getRange();
9146 // Create the resulting type.
9147 ElaboratedTypeKeyword Kwd = TypeWithKeyword::getKeywordForTagTypeKind(Kind);
9148 QualType Result = Context.getDependentNameType(Kwd, NNS, Name);
9150 // Create type-source location information for this type.
9152 DependentNameTypeLoc TL = TLB.push<DependentNameTypeLoc>(Result);
9153 TL.setElaboratedKeywordLoc(TagLoc);
9154 TL.setQualifierLoc(SS.getWithLocInContext(Context));
9155 TL.setNameLoc(NameLoc);
9156 return CreateParsedType(Result, TLB.getTypeSourceInfo(Context, Result));
9160 Sema::ActOnTypenameType(Scope *S, SourceLocation TypenameLoc,
9161 const CXXScopeSpec &SS, const IdentifierInfo &II,
9162 SourceLocation IdLoc) {
9166 if (TypenameLoc.isValid() && S && !S->getTemplateParamParent())
9168 getLangOpts().CPlusPlus11 ?
9169 diag::warn_cxx98_compat_typename_outside_of_template :
9170 diag::ext_typename_outside_of_template)
9171 << FixItHint::CreateRemoval(TypenameLoc);
9173 NestedNameSpecifierLoc QualifierLoc = SS.getWithLocInContext(Context);
9174 QualType T = CheckTypenameType(TypenameLoc.isValid()? ETK_Typename : ETK_None,
9175 TypenameLoc, QualifierLoc, II, IdLoc);
9179 TypeSourceInfo *TSI = Context.CreateTypeSourceInfo(T);
9180 if (isa<DependentNameType>(T)) {
9181 DependentNameTypeLoc TL = TSI->getTypeLoc().castAs<DependentNameTypeLoc>();
9182 TL.setElaboratedKeywordLoc(TypenameLoc);
9183 TL.setQualifierLoc(QualifierLoc);
9184 TL.setNameLoc(IdLoc);
9186 ElaboratedTypeLoc TL = TSI->getTypeLoc().castAs<ElaboratedTypeLoc>();
9187 TL.setElaboratedKeywordLoc(TypenameLoc);
9188 TL.setQualifierLoc(QualifierLoc);
9189 TL.getNamedTypeLoc().castAs<TypeSpecTypeLoc>().setNameLoc(IdLoc);
9192 return CreateParsedType(T, TSI);
9196 Sema::ActOnTypenameType(Scope *S,
9197 SourceLocation TypenameLoc,
9198 const CXXScopeSpec &SS,
9199 SourceLocation TemplateKWLoc,
9200 TemplateTy TemplateIn,
9201 IdentifierInfo *TemplateII,
9202 SourceLocation TemplateIILoc,
9203 SourceLocation LAngleLoc,
9204 ASTTemplateArgsPtr TemplateArgsIn,
9205 SourceLocation RAngleLoc) {
9206 if (TypenameLoc.isValid() && S && !S->getTemplateParamParent())
9208 getLangOpts().CPlusPlus11 ?
9209 diag::warn_cxx98_compat_typename_outside_of_template :
9210 diag::ext_typename_outside_of_template)
9211 << FixItHint::CreateRemoval(TypenameLoc);
9213 // Strangely, non-type results are not ignored by this lookup, so the
9214 // program is ill-formed if it finds an injected-class-name.
9215 if (TypenameLoc.isValid()) {
9217 dyn_cast_or_null<CXXRecordDecl>(computeDeclContext(SS, false));
9218 if (LookupRD && LookupRD->getIdentifier() == TemplateII) {
9220 diag::ext_out_of_line_qualified_id_type_names_constructor)
9221 << TemplateII << 0 /*injected-class-name used as template name*/
9222 << (TemplateKWLoc.isValid() ? 1 : 0 /*'template'/'typename' keyword*/);
9226 // Translate the parser's template argument list in our AST format.
9227 TemplateArgumentListInfo TemplateArgs(LAngleLoc, RAngleLoc);
9228 translateTemplateArguments(TemplateArgsIn, TemplateArgs);
9230 TemplateName Template = TemplateIn.get();
9231 if (DependentTemplateName *DTN = Template.getAsDependentTemplateName()) {
9232 // Construct a dependent template specialization type.
9233 assert(DTN && "dependent template has non-dependent name?");
9234 assert(DTN->getQualifier() == SS.getScopeRep());
9235 QualType T = Context.getDependentTemplateSpecializationType(ETK_Typename,
9236 DTN->getQualifier(),
9237 DTN->getIdentifier(),
9240 // Create source-location information for this type.
9241 TypeLocBuilder Builder;
9242 DependentTemplateSpecializationTypeLoc SpecTL
9243 = Builder.push<DependentTemplateSpecializationTypeLoc>(T);
9244 SpecTL.setElaboratedKeywordLoc(TypenameLoc);
9245 SpecTL.setQualifierLoc(SS.getWithLocInContext(Context));
9246 SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
9247 SpecTL.setTemplateNameLoc(TemplateIILoc);
9248 SpecTL.setLAngleLoc(LAngleLoc);
9249 SpecTL.setRAngleLoc(RAngleLoc);
9250 for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I)
9251 SpecTL.setArgLocInfo(I, TemplateArgs[I].getLocInfo());
9252 return CreateParsedType(T, Builder.getTypeSourceInfo(Context, T));
9255 QualType T = CheckTemplateIdType(Template, TemplateIILoc, TemplateArgs);
9259 // Provide source-location information for the template specialization type.
9260 TypeLocBuilder Builder;
9261 TemplateSpecializationTypeLoc SpecTL
9262 = Builder.push<TemplateSpecializationTypeLoc>(T);
9263 SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
9264 SpecTL.setTemplateNameLoc(TemplateIILoc);
9265 SpecTL.setLAngleLoc(LAngleLoc);
9266 SpecTL.setRAngleLoc(RAngleLoc);
9267 for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I)
9268 SpecTL.setArgLocInfo(I, TemplateArgs[I].getLocInfo());
9270 T = Context.getElaboratedType(ETK_Typename, SS.getScopeRep(), T);
9271 ElaboratedTypeLoc TL = Builder.push<ElaboratedTypeLoc>(T);
9272 TL.setElaboratedKeywordLoc(TypenameLoc);
9273 TL.setQualifierLoc(SS.getWithLocInContext(Context));
9275 TypeSourceInfo *TSI = Builder.getTypeSourceInfo(Context, T);
9276 return CreateParsedType(T, TSI);
9280 /// Determine whether this failed name lookup should be treated as being
9281 /// disabled by a usage of std::enable_if.
9282 static bool isEnableIf(NestedNameSpecifierLoc NNS, const IdentifierInfo &II,
9283 SourceRange &CondRange) {
9284 // We must be looking for a ::type...
9285 if (!II.isStr("type"))
9288 // ... within an explicitly-written template specialization...
9289 if (!NNS || !NNS.getNestedNameSpecifier()->getAsType())
9291 TypeLoc EnableIfTy = NNS.getTypeLoc();
9292 TemplateSpecializationTypeLoc EnableIfTSTLoc =
9293 EnableIfTy.getAs<TemplateSpecializationTypeLoc>();
9294 if (!EnableIfTSTLoc || EnableIfTSTLoc.getNumArgs() == 0)
9296 const TemplateSpecializationType *EnableIfTST =
9297 cast<TemplateSpecializationType>(EnableIfTSTLoc.getTypePtr());
9299 // ... which names a complete class template declaration...
9300 const TemplateDecl *EnableIfDecl =
9301 EnableIfTST->getTemplateName().getAsTemplateDecl();
9302 if (!EnableIfDecl || EnableIfTST->isIncompleteType())
9305 // ... called "enable_if".
9306 const IdentifierInfo *EnableIfII =
9307 EnableIfDecl->getDeclName().getAsIdentifierInfo();
9308 if (!EnableIfII || !EnableIfII->isStr("enable_if"))
9311 // Assume the first template argument is the condition.
9312 CondRange = EnableIfTSTLoc.getArgLoc(0).getSourceRange();
9316 /// \brief Build the type that describes a C++ typename specifier,
9317 /// e.g., "typename T::type".
9319 Sema::CheckTypenameType(ElaboratedTypeKeyword Keyword,
9320 SourceLocation KeywordLoc,
9321 NestedNameSpecifierLoc QualifierLoc,
9322 const IdentifierInfo &II,
9323 SourceLocation IILoc) {
9325 SS.Adopt(QualifierLoc);
9327 DeclContext *Ctx = computeDeclContext(SS);
9329 // If the nested-name-specifier is dependent and couldn't be
9330 // resolved to a type, build a typename type.
9331 assert(QualifierLoc.getNestedNameSpecifier()->isDependent());
9332 return Context.getDependentNameType(Keyword,
9333 QualifierLoc.getNestedNameSpecifier(),
9337 // If the nested-name-specifier refers to the current instantiation,
9338 // the "typename" keyword itself is superfluous. In C++03, the
9339 // program is actually ill-formed. However, DR 382 (in C++0x CD1)
9340 // allows such extraneous "typename" keywords, and we retroactively
9341 // apply this DR to C++03 code with only a warning. In any case we continue.
9343 if (RequireCompleteDeclContext(SS, Ctx))
9346 DeclarationName Name(&II);
9347 LookupResult Result(*this, Name, IILoc, LookupOrdinaryName);
9348 LookupQualifiedName(Result, Ctx, SS);
9349 unsigned DiagID = 0;
9350 Decl *Referenced = nullptr;
9351 switch (Result.getResultKind()) {
9352 case LookupResult::NotFound: {
9353 // If we're looking up 'type' within a template named 'enable_if', produce
9354 // a more specific diagnostic.
9355 SourceRange CondRange;
9356 if (isEnableIf(QualifierLoc, II, CondRange)) {
9357 Diag(CondRange.getBegin(), diag::err_typename_nested_not_found_enable_if)
9358 << Ctx << CondRange;
9362 DiagID = diag::err_typename_nested_not_found;
9366 case LookupResult::FoundUnresolvedValue: {
9367 // We found a using declaration that is a value. Most likely, the using
9368 // declaration itself is meant to have the 'typename' keyword.
9369 SourceRange FullRange(KeywordLoc.isValid() ? KeywordLoc : SS.getBeginLoc(),
9371 Diag(IILoc, diag::err_typename_refers_to_using_value_decl)
9372 << Name << Ctx << FullRange;
9373 if (UnresolvedUsingValueDecl *Using
9374 = dyn_cast<UnresolvedUsingValueDecl>(Result.getRepresentativeDecl())){
9375 SourceLocation Loc = Using->getQualifierLoc().getBeginLoc();
9376 Diag(Loc, diag::note_using_value_decl_missing_typename)
9377 << FixItHint::CreateInsertion(Loc, "typename ");
9380 // Fall through to create a dependent typename type, from which we can recover
9383 case LookupResult::NotFoundInCurrentInstantiation:
9384 // Okay, it's a member of an unknown instantiation.
9385 return Context.getDependentNameType(Keyword,
9386 QualifierLoc.getNestedNameSpecifier(),
9389 case LookupResult::Found:
9390 if (TypeDecl *Type = dyn_cast<TypeDecl>(Result.getFoundDecl())) {
9391 // C++ [class.qual]p2:
9392 // In a lookup in which function names are not ignored and the
9393 // nested-name-specifier nominates a class C, if the name specified
9394 // after the nested-name-specifier, when looked up in C, is the
9395 // injected-class-name of C [...] then the name is instead considered
9396 // to name the constructor of class C.
9398 // Unlike in an elaborated-type-specifier, function names are not ignored
9399 // in typename-specifier lookup. However, they are ignored in all the
9400 // contexts where we form a typename type with no keyword (that is, in
9401 // mem-initializer-ids, base-specifiers, and elaborated-type-specifiers).
9403 // FIXME: That's not strictly true: mem-initializer-id lookup does not
9404 // ignore functions, but that appears to be an oversight.
9405 auto *LookupRD = dyn_cast_or_null<CXXRecordDecl>(Ctx);
9406 auto *FoundRD = dyn_cast<CXXRecordDecl>(Type);
9407 if (Keyword == ETK_Typename && LookupRD && FoundRD &&
9408 FoundRD->isInjectedClassName() &&
9409 declaresSameEntity(LookupRD, cast<Decl>(FoundRD->getParent())))
9410 Diag(IILoc, diag::ext_out_of_line_qualified_id_type_names_constructor)
9411 << &II << 1 << 0 /*'typename' keyword used*/;
9413 // We found a type. Build an ElaboratedType, since the
9414 // typename-specifier was just sugar.
9415 MarkAnyDeclReferenced(Type->getLocation(), Type, /*OdrUse=*/false);
9416 return Context.getElaboratedType(Keyword,
9417 QualifierLoc.getNestedNameSpecifier(),
9418 Context.getTypeDeclType(Type));
9421 // C++ [dcl.type.simple]p2:
9422 // A type-specifier of the form
9423 // typename[opt] nested-name-specifier[opt] template-name
9424 // is a placeholder for a deduced class type [...].
9425 if (getLangOpts().CPlusPlus1z) {
9426 if (auto *TD = getAsTypeTemplateDecl(Result.getFoundDecl())) {
9427 return Context.getElaboratedType(
9428 Keyword, QualifierLoc.getNestedNameSpecifier(),
9429 Context.getDeducedTemplateSpecializationType(TemplateName(TD),
9430 QualType(), false));
9434 DiagID = diag::err_typename_nested_not_type;
9435 Referenced = Result.getFoundDecl();
9438 case LookupResult::FoundOverloaded:
9439 DiagID = diag::err_typename_nested_not_type;
9440 Referenced = *Result.begin();
9443 case LookupResult::Ambiguous:
9447 // If we get here, it's because name lookup did not find a
9448 // type. Emit an appropriate diagnostic and return an error.
9449 SourceRange FullRange(KeywordLoc.isValid() ? KeywordLoc : SS.getBeginLoc(),
9451 Diag(IILoc, DiagID) << FullRange << Name << Ctx;
9453 Diag(Referenced->getLocation(), diag::note_typename_refers_here)
9459 // See Sema::RebuildTypeInCurrentInstantiation
9460 class CurrentInstantiationRebuilder
9461 : public TreeTransform<CurrentInstantiationRebuilder> {
9463 DeclarationName Entity;
9466 typedef TreeTransform<CurrentInstantiationRebuilder> inherited;
9468 CurrentInstantiationRebuilder(Sema &SemaRef,
9470 DeclarationName Entity)
9471 : TreeTransform<CurrentInstantiationRebuilder>(SemaRef),
9472 Loc(Loc), Entity(Entity) { }
9474 /// \brief Determine whether the given type \p T has already been
9477 /// For the purposes of type reconstruction, a type has already been
9478 /// transformed if it is NULL or if it is not dependent.
9479 bool AlreadyTransformed(QualType T) {
9480 return T.isNull() || !T->isDependentType();
9483 /// \brief Returns the location of the entity whose type is being
9485 SourceLocation getBaseLocation() { return Loc; }
9487 /// \brief Returns the name of the entity whose type is being rebuilt.
9488 DeclarationName getBaseEntity() { return Entity; }
9490 /// \brief Sets the "base" location and entity when that
9491 /// information is known based on another transformation.
9492 void setBase(SourceLocation Loc, DeclarationName Entity) {
9494 this->Entity = Entity;
9497 ExprResult TransformLambdaExpr(LambdaExpr *E) {
9498 // Lambdas never need to be transformed.
9502 } // end anonymous namespace
9504 /// \brief Rebuilds a type within the context of the current instantiation.
9506 /// The type \p T is part of the type of an out-of-line member definition of
9507 /// a class template (or class template partial specialization) that was parsed
9508 /// and constructed before we entered the scope of the class template (or
9509 /// partial specialization thereof). This routine will rebuild that type now
9510 /// that we have entered the declarator's scope, which may produce different
9511 /// canonical types, e.g.,
9514 /// template<typename T>
9516 /// typedef T* pointer;
9520 /// template<typename T>
9521 /// typename X<T>::pointer X<T>::data() { ... }
9524 /// Here, the type "typename X<T>::pointer" will be created as a DependentNameType,
9525 /// since we do not know that we can look into X<T> when we parsed the type.
9526 /// This function will rebuild the type, performing the lookup of "pointer"
9527 /// in X<T> and returning an ElaboratedType whose canonical type is the same
9528 /// as the canonical type of T*, allowing the return types of the out-of-line
9529 /// definition and the declaration to match.
9530 TypeSourceInfo *Sema::RebuildTypeInCurrentInstantiation(TypeSourceInfo *T,
9532 DeclarationName Name) {
9533 if (!T || !T->getType()->isDependentType())
9536 CurrentInstantiationRebuilder Rebuilder(*this, Loc, Name);
9537 return Rebuilder.TransformType(T);
9540 ExprResult Sema::RebuildExprInCurrentInstantiation(Expr *E) {
9541 CurrentInstantiationRebuilder Rebuilder(*this, E->getExprLoc(),
9543 return Rebuilder.TransformExpr(E);
9546 bool Sema::RebuildNestedNameSpecifierInCurrentInstantiation(CXXScopeSpec &SS) {
9550 NestedNameSpecifierLoc QualifierLoc = SS.getWithLocInContext(Context);
9551 CurrentInstantiationRebuilder Rebuilder(*this, SS.getRange().getBegin(),
9553 NestedNameSpecifierLoc Rebuilt
9554 = Rebuilder.TransformNestedNameSpecifierLoc(QualifierLoc);
9562 /// \brief Rebuild the template parameters now that we know we're in a current
9564 bool Sema::RebuildTemplateParamsInCurrentInstantiation(
9565 TemplateParameterList *Params) {
9566 for (unsigned I = 0, N = Params->size(); I != N; ++I) {
9567 Decl *Param = Params->getParam(I);
9569 // There is nothing to rebuild in a type parameter.
9570 if (isa<TemplateTypeParmDecl>(Param))
9573 // Rebuild the template parameter list of a template template parameter.
9574 if (TemplateTemplateParmDecl *TTP
9575 = dyn_cast<TemplateTemplateParmDecl>(Param)) {
9576 if (RebuildTemplateParamsInCurrentInstantiation(
9577 TTP->getTemplateParameters()))
9583 // Rebuild the type of a non-type template parameter.
9584 NonTypeTemplateParmDecl *NTTP = cast<NonTypeTemplateParmDecl>(Param);
9585 TypeSourceInfo *NewTSI
9586 = RebuildTypeInCurrentInstantiation(NTTP->getTypeSourceInfo(),
9587 NTTP->getLocation(),
9588 NTTP->getDeclName());
9592 if (NewTSI != NTTP->getTypeSourceInfo()) {
9593 NTTP->setTypeSourceInfo(NewTSI);
9594 NTTP->setType(NewTSI->getType());
9601 /// \brief Produces a formatted string that describes the binding of
9602 /// template parameters to template arguments.
9604 Sema::getTemplateArgumentBindingsText(const TemplateParameterList *Params,
9605 const TemplateArgumentList &Args) {
9606 return getTemplateArgumentBindingsText(Params, Args.data(), Args.size());
9610 Sema::getTemplateArgumentBindingsText(const TemplateParameterList *Params,
9611 const TemplateArgument *Args,
9613 SmallString<128> Str;
9614 llvm::raw_svector_ostream Out(Str);
9616 if (!Params || Params->size() == 0 || NumArgs == 0)
9617 return std::string();
9619 for (unsigned I = 0, N = Params->size(); I != N; ++I) {
9628 if (const IdentifierInfo *Id = Params->getParam(I)->getIdentifier()) {
9629 Out << Id->getName();
9635 Args[I].print(getPrintingPolicy(), Out);
9642 void Sema::MarkAsLateParsedTemplate(FunctionDecl *FD, Decl *FnD,
9643 CachedTokens &Toks) {
9647 auto LPT = llvm::make_unique<LateParsedTemplate>();
9649 // Take tokens to avoid allocations
9650 LPT->Toks.swap(Toks);
9652 LateParsedTemplateMap.insert(std::make_pair(FD, std::move(LPT)));
9654 FD->setLateTemplateParsed(true);
9657 void Sema::UnmarkAsLateParsedTemplate(FunctionDecl *FD) {
9660 FD->setLateTemplateParsed(false);
9663 bool Sema::IsInsideALocalClassWithinATemplateFunction() {
9664 DeclContext *DC = CurContext;
9667 if (CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(CurContext)) {
9668 const FunctionDecl *FD = RD->isLocalClass();
9669 return (FD && FD->getTemplatedKind() != FunctionDecl::TK_NonTemplate);
9670 } else if (DC->isTranslationUnit() || DC->isNamespace())
9673 DC = DC->getParent();
9679 /// \brief Walk the path from which a declaration was instantiated, and check
9680 /// that every explicit specialization along that path is visible. This enforces
9681 /// C++ [temp.expl.spec]/6:
9683 /// If a template, a member template or a member of a class template is
9684 /// explicitly specialized then that specialization shall be declared before
9685 /// the first use of that specialization that would cause an implicit
9686 /// instantiation to take place, in every translation unit in which such a
9687 /// use occurs; no diagnostic is required.
9689 /// and also C++ [temp.class.spec]/1:
9691 /// A partial specialization shall be declared before the first use of a
9692 /// class template specialization that would make use of the partial
9693 /// specialization as the result of an implicit or explicit instantiation
9694 /// in every translation unit in which such a use occurs; no diagnostic is
9696 class ExplicitSpecializationVisibilityChecker {
9699 llvm::SmallVector<Module *, 8> Modules;
9702 ExplicitSpecializationVisibilityChecker(Sema &S, SourceLocation Loc)
9705 void check(NamedDecl *ND) {
9706 if (auto *FD = dyn_cast<FunctionDecl>(ND))
9707 return checkImpl(FD);
9708 if (auto *RD = dyn_cast<CXXRecordDecl>(ND))
9709 return checkImpl(RD);
9710 if (auto *VD = dyn_cast<VarDecl>(ND))
9711 return checkImpl(VD);
9712 if (auto *ED = dyn_cast<EnumDecl>(ND))
9713 return checkImpl(ED);
9717 void diagnose(NamedDecl *D, bool IsPartialSpec) {
9718 auto Kind = IsPartialSpec ? Sema::MissingImportKind::PartialSpecialization
9719 : Sema::MissingImportKind::ExplicitSpecialization;
9720 const bool Recover = true;
9722 // If we got a custom set of modules (because only a subset of the
9723 // declarations are interesting), use them, otherwise let
9724 // diagnoseMissingImport intelligently pick some.
9725 if (Modules.empty())
9726 S.diagnoseMissingImport(Loc, D, Kind, Recover);
9728 S.diagnoseMissingImport(Loc, D, D->getLocation(), Modules, Kind, Recover);
9731 // Check a specific declaration. There are three problematic cases:
9733 // 1) The declaration is an explicit specialization of a template
9735 // 2) The declaration is an explicit specialization of a member of an
9737 // 3) The declaration is an instantiation of a template, and that template
9738 // is an explicit specialization of a member of a templated class.
9740 // We don't need to go any deeper than that, as the instantiation of the
9741 // surrounding class / etc is not triggered by whatever triggered this
9742 // instantiation, and thus should be checked elsewhere.
9743 template<typename SpecDecl>
9744 void checkImpl(SpecDecl *Spec) {
9745 bool IsHiddenExplicitSpecialization = false;
9746 if (Spec->getTemplateSpecializationKind() == TSK_ExplicitSpecialization) {
9747 IsHiddenExplicitSpecialization =
9748 Spec->getMemberSpecializationInfo()
9749 ? !S.hasVisibleMemberSpecialization(Spec, &Modules)
9750 : !S.hasVisibleExplicitSpecialization(Spec, &Modules);
9752 checkInstantiated(Spec);
9755 if (IsHiddenExplicitSpecialization)
9756 diagnose(Spec->getMostRecentDecl(), false);
9759 void checkInstantiated(FunctionDecl *FD) {
9760 if (auto *TD = FD->getPrimaryTemplate())
9764 void checkInstantiated(CXXRecordDecl *RD) {
9765 auto *SD = dyn_cast<ClassTemplateSpecializationDecl>(RD);
9769 auto From = SD->getSpecializedTemplateOrPartial();
9770 if (auto *TD = From.dyn_cast<ClassTemplateDecl *>())
9773 From.dyn_cast<ClassTemplatePartialSpecializationDecl *>()) {
9774 if (!S.hasVisibleDeclaration(TD))
9780 void checkInstantiated(VarDecl *RD) {
9781 auto *SD = dyn_cast<VarTemplateSpecializationDecl>(RD);
9785 auto From = SD->getSpecializedTemplateOrPartial();
9786 if (auto *TD = From.dyn_cast<VarTemplateDecl *>())
9789 From.dyn_cast<VarTemplatePartialSpecializationDecl *>()) {
9790 if (!S.hasVisibleDeclaration(TD))
9796 void checkInstantiated(EnumDecl *FD) {}
9798 template<typename TemplDecl>
9799 void checkTemplate(TemplDecl *TD) {
9800 if (TD->isMemberSpecialization()) {
9801 if (!S.hasVisibleMemberSpecialization(TD, &Modules))
9802 diagnose(TD->getMostRecentDecl(), false);
9806 } // end anonymous namespace
9808 void Sema::checkSpecializationVisibility(SourceLocation Loc, NamedDecl *Spec) {
9809 if (!getLangOpts().Modules)
9812 ExplicitSpecializationVisibilityChecker(*this, Loc).check(Spec);
9815 /// \brief Check whether a template partial specialization that we've discovered
9816 /// is hidden, and produce suitable diagnostics if so.
9817 void Sema::checkPartialSpecializationVisibility(SourceLocation Loc,
9819 llvm::SmallVector<Module *, 8> Modules;
9820 if (!hasVisibleDeclaration(Spec, &Modules))
9821 diagnoseMissingImport(Loc, Spec, Spec->getLocation(), Modules,
9822 MissingImportKind::PartialSpecialization,