1 //===------- SemaTemplate.cpp - Semantic Analysis for C++ Templates -------===//
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //===----------------------------------------------------------------------===//
8 // This file implements semantic analysis for C++ templates.
9 //===----------------------------------------------------------------------===//
11 #include "TreeTransform.h"
12 #include "clang/AST/ASTConsumer.h"
13 #include "clang/AST/ASTContext.h"
14 #include "clang/AST/DeclFriend.h"
15 #include "clang/AST/DeclTemplate.h"
16 #include "clang/AST/Expr.h"
17 #include "clang/AST/ExprCXX.h"
18 #include "clang/AST/RecursiveASTVisitor.h"
19 #include "clang/AST/TypeVisitor.h"
20 #include "clang/Basic/Builtins.h"
21 #include "clang/Basic/LangOptions.h"
22 #include "clang/Basic/PartialDiagnostic.h"
23 #include "clang/Basic/Stack.h"
24 #include "clang/Basic/TargetInfo.h"
25 #include "clang/Sema/DeclSpec.h"
26 #include "clang/Sema/Lookup.h"
27 #include "clang/Sema/Overload.h"
28 #include "clang/Sema/ParsedTemplate.h"
29 #include "clang/Sema/Scope.h"
30 #include "clang/Sema/SemaInternal.h"
31 #include "clang/Sema/Template.h"
32 #include "clang/Sema/TemplateDeduction.h"
33 #include "llvm/ADT/SmallBitVector.h"
34 #include "llvm/ADT/SmallString.h"
35 #include "llvm/ADT/StringExtras.h"
38 using namespace clang;
41 // Exported for use by Parser.
43 clang::getTemplateParamsRange(TemplateParameterList const * const *Ps,
45 if (!N) return SourceRange();
46 return SourceRange(Ps[0]->getTemplateLoc(), Ps[N-1]->getRAngleLoc());
49 unsigned Sema::getTemplateDepth(Scope *S) const {
52 // Each template parameter scope represents one level of template parameter
54 for (Scope *TempParamScope = S->getTemplateParamParent();
55 TempParamScope && !Depth;
56 TempParamScope = TempParamScope->getParent()->getTemplateParamParent()) {
60 // Note that there are template parameters with the given depth.
61 auto ParamsAtDepth = [&](unsigned D) { Depth = std::max(Depth, D + 1); };
63 // Look for parameters of an enclosing generic lambda. We don't create a
64 // template parameter scope for these.
65 for (FunctionScopeInfo *FSI : getFunctionScopes()) {
66 if (auto *LSI = dyn_cast<LambdaScopeInfo>(FSI)) {
67 if (!LSI->TemplateParams.empty()) {
68 ParamsAtDepth(LSI->AutoTemplateParameterDepth);
71 if (LSI->GLTemplateParameterList) {
72 ParamsAtDepth(LSI->GLTemplateParameterList->getDepth());
78 // Look for parameters of an enclosing terse function template. We don't
79 // create a template parameter scope for these either.
80 for (const InventedTemplateParameterInfo &Info :
81 getInventedParameterInfos()) {
82 if (!Info.TemplateParams.empty()) {
83 ParamsAtDepth(Info.AutoTemplateParameterDepth);
91 /// \brief Determine whether the declaration found is acceptable as the name
92 /// of a template and, if so, return that template declaration. Otherwise,
95 /// Note that this may return an UnresolvedUsingValueDecl if AllowDependent
96 /// is true. In all other cases it will return a TemplateDecl (or null).
97 NamedDecl *Sema::getAsTemplateNameDecl(NamedDecl *D,
98 bool AllowFunctionTemplates,
99 bool AllowDependent) {
100 D = D->getUnderlyingDecl();
102 if (isa<TemplateDecl>(D)) {
103 if (!AllowFunctionTemplates && isa<FunctionTemplateDecl>(D))
109 if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(D)) {
110 // C++ [temp.local]p1:
111 // Like normal (non-template) classes, class templates have an
112 // injected-class-name (Clause 9). The injected-class-name
113 // can be used with or without a template-argument-list. When
114 // it is used without a template-argument-list, it is
115 // equivalent to the injected-class-name followed by the
116 // template-parameters of the class template enclosed in
117 // <>. When it is used with a template-argument-list, it
118 // refers to the specified class template specialization,
119 // which could be the current specialization or another
121 if (Record->isInjectedClassName()) {
122 Record = cast<CXXRecordDecl>(Record->getDeclContext());
123 if (Record->getDescribedClassTemplate())
124 return Record->getDescribedClassTemplate();
126 if (ClassTemplateSpecializationDecl *Spec
127 = dyn_cast<ClassTemplateSpecializationDecl>(Record))
128 return Spec->getSpecializedTemplate();
134 // 'using Dependent::foo;' can resolve to a template name.
135 // 'using typename Dependent::foo;' cannot (not even if 'foo' is an
136 // injected-class-name).
137 if (AllowDependent && isa<UnresolvedUsingValueDecl>(D))
143 void Sema::FilterAcceptableTemplateNames(LookupResult &R,
144 bool AllowFunctionTemplates,
145 bool AllowDependent) {
146 LookupResult::Filter filter = R.makeFilter();
147 while (filter.hasNext()) {
148 NamedDecl *Orig = filter.next();
149 if (!getAsTemplateNameDecl(Orig, AllowFunctionTemplates, AllowDependent))
155 bool Sema::hasAnyAcceptableTemplateNames(LookupResult &R,
156 bool AllowFunctionTemplates,
158 bool AllowNonTemplateFunctions) {
159 for (LookupResult::iterator I = R.begin(), IEnd = R.end(); I != IEnd; ++I) {
160 if (getAsTemplateNameDecl(*I, AllowFunctionTemplates, AllowDependent))
162 if (AllowNonTemplateFunctions &&
163 isa<FunctionDecl>((*I)->getUnderlyingDecl()))
170 TemplateNameKind Sema::isTemplateName(Scope *S,
172 bool hasTemplateKeyword,
173 const UnqualifiedId &Name,
174 ParsedType ObjectTypePtr,
175 bool EnteringContext,
176 TemplateTy &TemplateResult,
177 bool &MemberOfUnknownSpecialization,
178 bool Disambiguation) {
179 assert(getLangOpts().CPlusPlus && "No template names in C!");
181 DeclarationName TName;
182 MemberOfUnknownSpecialization = false;
184 switch (Name.getKind()) {
185 case UnqualifiedIdKind::IK_Identifier:
186 TName = DeclarationName(Name.Identifier);
189 case UnqualifiedIdKind::IK_OperatorFunctionId:
190 TName = Context.DeclarationNames.getCXXOperatorName(
191 Name.OperatorFunctionId.Operator);
194 case UnqualifiedIdKind::IK_LiteralOperatorId:
195 TName = Context.DeclarationNames.getCXXLiteralOperatorName(Name.Identifier);
199 return TNK_Non_template;
202 QualType ObjectType = ObjectTypePtr.get();
204 AssumedTemplateKind AssumedTemplate;
205 LookupResult R(*this, TName, Name.getBeginLoc(), LookupOrdinaryName);
206 if (LookupTemplateName(R, S, SS, ObjectType, EnteringContext,
207 MemberOfUnknownSpecialization, SourceLocation(),
208 &AssumedTemplate, Disambiguation))
209 return TNK_Non_template;
211 if (AssumedTemplate != AssumedTemplateKind::None) {
212 TemplateResult = TemplateTy::make(Context.getAssumedTemplateName(TName));
213 // Let the parser know whether we found nothing or found functions; if we
214 // found nothing, we want to more carefully check whether this is actually
215 // a function template name versus some other kind of undeclared identifier.
216 return AssumedTemplate == AssumedTemplateKind::FoundNothing
217 ? TNK_Undeclared_template
218 : TNK_Function_template;
222 return TNK_Non_template;
224 NamedDecl *D = nullptr;
225 if (R.isAmbiguous()) {
226 // If we got an ambiguity involving a non-function template, treat this
227 // as a template name, and pick an arbitrary template for error recovery.
228 bool AnyFunctionTemplates = false;
229 for (NamedDecl *FoundD : R) {
230 if (NamedDecl *FoundTemplate = getAsTemplateNameDecl(FoundD)) {
231 if (isa<FunctionTemplateDecl>(FoundTemplate))
232 AnyFunctionTemplates = true;
240 // If we didn't find any templates at all, this isn't a template name.
241 // Leave the ambiguity for a later lookup to diagnose.
242 if (!D && !AnyFunctionTemplates) {
243 R.suppressDiagnostics();
244 return TNK_Non_template;
247 // If the only templates were function templates, filter out the rest.
248 // We'll diagnose the ambiguity later.
250 FilterAcceptableTemplateNames(R);
253 // At this point, we have either picked a single template name declaration D
254 // or we have a non-empty set of results R containing either one template name
255 // declaration or a set of function templates.
257 TemplateName Template;
258 TemplateNameKind TemplateKind;
260 unsigned ResultCount = R.end() - R.begin();
261 if (!D && ResultCount > 1) {
262 // We assume that we'll preserve the qualifier from a function
263 // template name in other ways.
264 Template = Context.getOverloadedTemplateName(R.begin(), R.end());
265 TemplateKind = TNK_Function_template;
267 // We'll do this lookup again later.
268 R.suppressDiagnostics();
271 D = getAsTemplateNameDecl(*R.begin());
272 assert(D && "unambiguous result is not a template name");
275 if (isa<UnresolvedUsingValueDecl>(D)) {
276 // We don't yet know whether this is a template-name or not.
277 MemberOfUnknownSpecialization = true;
278 return TNK_Non_template;
281 TemplateDecl *TD = cast<TemplateDecl>(D);
283 if (SS.isSet() && !SS.isInvalid()) {
284 NestedNameSpecifier *Qualifier = SS.getScopeRep();
285 Template = Context.getQualifiedTemplateName(Qualifier,
286 hasTemplateKeyword, TD);
288 Template = TemplateName(TD);
291 if (isa<FunctionTemplateDecl>(TD)) {
292 TemplateKind = TNK_Function_template;
294 // We'll do this lookup again later.
295 R.suppressDiagnostics();
297 assert(isa<ClassTemplateDecl>(TD) || isa<TemplateTemplateParmDecl>(TD) ||
298 isa<TypeAliasTemplateDecl>(TD) || isa<VarTemplateDecl>(TD) ||
299 isa<BuiltinTemplateDecl>(TD) || isa<ConceptDecl>(TD));
301 isa<VarTemplateDecl>(TD) ? TNK_Var_template :
302 isa<ConceptDecl>(TD) ? TNK_Concept_template :
307 TemplateResult = TemplateTy::make(Template);
311 bool Sema::isDeductionGuideName(Scope *S, const IdentifierInfo &Name,
312 SourceLocation NameLoc,
313 ParsedTemplateTy *Template) {
315 bool MemberOfUnknownSpecialization = false;
317 // We could use redeclaration lookup here, but we don't need to: the
318 // syntactic form of a deduction guide is enough to identify it even
319 // if we can't look up the template name at all.
320 LookupResult R(*this, DeclarationName(&Name), NameLoc, LookupOrdinaryName);
321 if (LookupTemplateName(R, S, SS, /*ObjectType*/ QualType(),
322 /*EnteringContext*/ false,
323 MemberOfUnknownSpecialization))
326 if (R.empty()) return false;
327 if (R.isAmbiguous()) {
328 // FIXME: Diagnose an ambiguity if we find at least one template.
329 R.suppressDiagnostics();
333 // We only treat template-names that name type templates as valid deduction
335 TemplateDecl *TD = R.getAsSingle<TemplateDecl>();
336 if (!TD || !getAsTypeTemplateDecl(TD))
340 *Template = TemplateTy::make(TemplateName(TD));
344 bool Sema::DiagnoseUnknownTemplateName(const IdentifierInfo &II,
345 SourceLocation IILoc,
347 const CXXScopeSpec *SS,
348 TemplateTy &SuggestedTemplate,
349 TemplateNameKind &SuggestedKind) {
350 // We can't recover unless there's a dependent scope specifier preceding the
352 // FIXME: Typo correction?
353 if (!SS || !SS->isSet() || !isDependentScopeSpecifier(*SS) ||
354 computeDeclContext(*SS))
357 // The code is missing a 'template' keyword prior to the dependent template
359 NestedNameSpecifier *Qualifier = (NestedNameSpecifier*)SS->getScopeRep();
360 Diag(IILoc, diag::err_template_kw_missing)
361 << Qualifier << II.getName()
362 << FixItHint::CreateInsertion(IILoc, "template ");
364 = TemplateTy::make(Context.getDependentTemplateName(Qualifier, &II));
365 SuggestedKind = TNK_Dependent_template_name;
369 bool Sema::LookupTemplateName(LookupResult &Found,
370 Scope *S, CXXScopeSpec &SS,
372 bool EnteringContext,
373 bool &MemberOfUnknownSpecialization,
374 SourceLocation TemplateKWLoc,
375 AssumedTemplateKind *ATK,
376 bool Disambiguation) {
378 *ATK = AssumedTemplateKind::None;
380 Found.setTemplateNameLookup(true);
382 // Determine where to perform name lookup
383 MemberOfUnknownSpecialization = false;
384 DeclContext *LookupCtx = nullptr;
385 bool IsDependent = false;
386 if (!ObjectType.isNull()) {
387 // This nested-name-specifier occurs in a member access expression, e.g.,
388 // x->B::f, and we are looking into the type of the object.
389 assert(!SS.isSet() && "ObjectType and scope specifier cannot coexist");
390 LookupCtx = computeDeclContext(ObjectType);
391 IsDependent = !LookupCtx && ObjectType->isDependentType();
392 assert((IsDependent || !ObjectType->isIncompleteType() ||
393 ObjectType->castAs<TagType>()->isBeingDefined()) &&
394 "Caller should have completed object type");
396 // Template names cannot appear inside an Objective-C class or object type
399 // FIXME: This is wrong. For example:
401 // template<typename T> using Vec = T __attribute__((ext_vector_type(4)));
403 // vi.Vec<int>::~Vec<int>();
405 // ... should be accepted but we will not treat 'Vec' as a template name
406 // here. The right thing to do would be to check if the name is a valid
407 // vector component name, and look up a template name if not. And similarly
408 // for lookups into Objective-C class and object types, where the same
409 // problem can arise.
410 if (ObjectType->isObjCObjectOrInterfaceType() ||
411 ObjectType->isVectorType()) {
415 } else if (SS.isSet()) {
416 // This nested-name-specifier occurs after another nested-name-specifier,
417 // so long into the context associated with the prior nested-name-specifier.
418 LookupCtx = computeDeclContext(SS, EnteringContext);
419 IsDependent = !LookupCtx;
421 // The declaration context must be complete.
422 if (LookupCtx && RequireCompleteDeclContext(SS, LookupCtx))
426 bool ObjectTypeSearchedInScope = false;
427 bool AllowFunctionTemplatesInLookup = true;
429 // Perform "qualified" name lookup into the declaration context we
430 // computed, which is either the type of the base of a member access
431 // expression or the declaration context associated with a prior
432 // nested-name-specifier.
433 LookupQualifiedName(Found, LookupCtx);
435 // FIXME: The C++ standard does not clearly specify what happens in the
436 // case where the object type is dependent, and implementations vary. In
437 // Clang, we treat a name after a . or -> as a template-name if lookup
438 // finds a non-dependent member or member of the current instantiation that
439 // is a type template, or finds no such members and lookup in the context
440 // of the postfix-expression finds a type template. In the latter case, the
441 // name is nonetheless dependent, and we may resolve it to a member of an
442 // unknown specialization when we come to instantiate the template.
443 IsDependent |= Found.wasNotFoundInCurrentInstantiation();
446 if (!SS.isSet() && (ObjectType.isNull() || Found.empty())) {
447 // C++ [basic.lookup.classref]p1:
448 // In a class member access expression (5.2.5), if the . or -> token is
449 // immediately followed by an identifier followed by a <, the
450 // identifier must be looked up to determine whether the < is the
451 // beginning of a template argument list (14.2) or a less-than operator.
452 // The identifier is first looked up in the class of the object
453 // expression. If the identifier is not found, it is then looked up in
454 // the context of the entire postfix-expression and shall name a class
457 LookupName(Found, S);
459 if (!ObjectType.isNull()) {
460 // FIXME: We should filter out all non-type templates here, particularly
461 // variable templates and concepts. But the exclusion of alias templates
462 // and template template parameters is a wording defect.
463 AllowFunctionTemplatesInLookup = false;
464 ObjectTypeSearchedInScope = true;
467 IsDependent |= Found.wasNotFoundInCurrentInstantiation();
470 if (Found.isAmbiguous())
473 if (ATK && !SS.isSet() && ObjectType.isNull() && TemplateKWLoc.isInvalid()) {
474 // C++2a [temp.names]p2:
475 // A name is also considered to refer to a template if it is an
476 // unqualified-id followed by a < and name lookup finds either one or more
477 // functions or finds nothing.
479 // To keep our behavior consistent, we apply the "finds nothing" part in
480 // all language modes, and diagnose the empty lookup in ActOnCallExpr if we
481 // successfully form a call to an undeclared template-id.
483 getLangOpts().CPlusPlus2a &&
484 std::all_of(Found.begin(), Found.end(), [](NamedDecl *ND) {
485 return isa<FunctionDecl>(ND->getUnderlyingDecl());
487 if (AllFunctions || (Found.empty() && !IsDependent)) {
488 // If lookup found any functions, or if this is a name that can only be
489 // used for a function, then strongly assume this is a function
491 *ATK = (Found.empty() && Found.getLookupName().isIdentifier())
492 ? AssumedTemplateKind::FoundNothing
493 : AssumedTemplateKind::FoundFunctions;
499 if (Found.empty() && !IsDependent && !Disambiguation) {
500 // If we did not find any names, and this is not a disambiguation, attempt
501 // to correct any typos.
502 DeclarationName Name = Found.getLookupName();
504 // Simple filter callback that, for keywords, only accepts the C++ *_cast
505 DefaultFilterCCC FilterCCC{};
506 FilterCCC.WantTypeSpecifiers = false;
507 FilterCCC.WantExpressionKeywords = false;
508 FilterCCC.WantRemainingKeywords = false;
509 FilterCCC.WantCXXNamedCasts = true;
510 if (TypoCorrection Corrected =
511 CorrectTypo(Found.getLookupNameInfo(), Found.getLookupKind(), S,
512 &SS, FilterCCC, CTK_ErrorRecovery, LookupCtx)) {
513 if (auto *ND = Corrected.getFoundDecl())
515 FilterAcceptableTemplateNames(Found);
516 if (Found.isAmbiguous()) {
518 } else if (!Found.empty()) {
519 Found.setLookupName(Corrected.getCorrection());
521 std::string CorrectedStr(Corrected.getAsString(getLangOpts()));
522 bool DroppedSpecifier = Corrected.WillReplaceSpecifier() &&
523 Name.getAsString() == CorrectedStr;
524 diagnoseTypo(Corrected, PDiag(diag::err_no_member_template_suggest)
525 << Name << LookupCtx << DroppedSpecifier
528 diagnoseTypo(Corrected, PDiag(diag::err_no_template_suggest) << Name);
534 NamedDecl *ExampleLookupResult =
535 Found.empty() ? nullptr : Found.getRepresentativeDecl();
536 FilterAcceptableTemplateNames(Found, AllowFunctionTemplatesInLookup);
539 MemberOfUnknownSpecialization = true;
543 // If a 'template' keyword was used, a lookup that finds only non-template
544 // names is an error.
545 if (ExampleLookupResult && TemplateKWLoc.isValid()) {
546 Diag(Found.getNameLoc(), diag::err_template_kw_refers_to_non_template)
547 << Found.getLookupName() << SS.getRange();
548 Diag(ExampleLookupResult->getUnderlyingDecl()->getLocation(),
549 diag::note_template_kw_refers_to_non_template)
550 << Found.getLookupName();
557 if (S && !ObjectType.isNull() && !ObjectTypeSearchedInScope &&
558 !getLangOpts().CPlusPlus11) {
559 // C++03 [basic.lookup.classref]p1:
560 // [...] If the lookup in the class of the object expression finds a
561 // template, the name is also looked up in the context of the entire
562 // postfix-expression and [...]
564 // Note: C++11 does not perform this second lookup.
565 LookupResult FoundOuter(*this, Found.getLookupName(), Found.getNameLoc(),
567 FoundOuter.setTemplateNameLookup(true);
568 LookupName(FoundOuter, S);
569 // FIXME: We silently accept an ambiguous lookup here, in violation of
571 FilterAcceptableTemplateNames(FoundOuter, /*AllowFunctionTemplates=*/false);
573 NamedDecl *OuterTemplate;
574 if (FoundOuter.empty()) {
575 // - if the name is not found, the name found in the class of the
576 // object expression is used, otherwise
577 } else if (FoundOuter.isAmbiguous() || !FoundOuter.isSingleResult() ||
579 getAsTemplateNameDecl(FoundOuter.getFoundDecl()))) {
580 // - if the name is found in the context of the entire
581 // postfix-expression and does not name a class template, the name
582 // found in the class of the object expression is used, otherwise
584 } else if (!Found.isSuppressingDiagnostics()) {
585 // - if the name found is a class template, it must refer to the same
586 // entity as the one found in the class of the object expression,
587 // otherwise the program is ill-formed.
588 if (!Found.isSingleResult() ||
589 getAsTemplateNameDecl(Found.getFoundDecl())->getCanonicalDecl() !=
590 OuterTemplate->getCanonicalDecl()) {
591 Diag(Found.getNameLoc(),
592 diag::ext_nested_name_member_ref_lookup_ambiguous)
593 << Found.getLookupName()
595 Diag(Found.getRepresentativeDecl()->getLocation(),
596 diag::note_ambig_member_ref_object_type)
598 Diag(FoundOuter.getFoundDecl()->getLocation(),
599 diag::note_ambig_member_ref_scope);
601 // Recover by taking the template that we found in the object
602 // expression's type.
610 void Sema::diagnoseExprIntendedAsTemplateName(Scope *S, ExprResult TemplateName,
612 SourceLocation Greater) {
613 if (TemplateName.isInvalid())
616 DeclarationNameInfo NameInfo;
618 LookupNameKind LookupKind;
620 DeclContext *LookupCtx = nullptr;
621 NamedDecl *Found = nullptr;
622 bool MissingTemplateKeyword = false;
624 // Figure out what name we looked up.
625 if (auto *DRE = dyn_cast<DeclRefExpr>(TemplateName.get())) {
626 NameInfo = DRE->getNameInfo();
627 SS.Adopt(DRE->getQualifierLoc());
628 LookupKind = LookupOrdinaryName;
629 Found = DRE->getFoundDecl();
630 } else if (auto *ME = dyn_cast<MemberExpr>(TemplateName.get())) {
631 NameInfo = ME->getMemberNameInfo();
632 SS.Adopt(ME->getQualifierLoc());
633 LookupKind = LookupMemberName;
634 LookupCtx = ME->getBase()->getType()->getAsCXXRecordDecl();
635 Found = ME->getMemberDecl();
636 } else if (auto *DSDRE =
637 dyn_cast<DependentScopeDeclRefExpr>(TemplateName.get())) {
638 NameInfo = DSDRE->getNameInfo();
639 SS.Adopt(DSDRE->getQualifierLoc());
640 MissingTemplateKeyword = true;
641 } else if (auto *DSME =
642 dyn_cast<CXXDependentScopeMemberExpr>(TemplateName.get())) {
643 NameInfo = DSME->getMemberNameInfo();
644 SS.Adopt(DSME->getQualifierLoc());
645 MissingTemplateKeyword = true;
647 llvm_unreachable("unexpected kind of potential template name");
650 // If this is a dependent-scope lookup, diagnose that the 'template' keyword
652 if (MissingTemplateKeyword) {
653 Diag(NameInfo.getBeginLoc(), diag::err_template_kw_missing)
654 << "" << NameInfo.getName().getAsString() << SourceRange(Less, Greater);
658 // Try to correct the name by looking for templates and C++ named casts.
659 struct TemplateCandidateFilter : CorrectionCandidateCallback {
661 TemplateCandidateFilter(Sema &S) : S(S) {
662 WantTypeSpecifiers = false;
663 WantExpressionKeywords = false;
664 WantRemainingKeywords = false;
665 WantCXXNamedCasts = true;
667 bool ValidateCandidate(const TypoCorrection &Candidate) override {
668 if (auto *ND = Candidate.getCorrectionDecl())
669 return S.getAsTemplateNameDecl(ND);
670 return Candidate.isKeyword();
673 std::unique_ptr<CorrectionCandidateCallback> clone() override {
674 return std::make_unique<TemplateCandidateFilter>(*this);
678 DeclarationName Name = NameInfo.getName();
679 TemplateCandidateFilter CCC(*this);
680 if (TypoCorrection Corrected = CorrectTypo(NameInfo, LookupKind, S, &SS, CCC,
681 CTK_ErrorRecovery, LookupCtx)) {
682 auto *ND = Corrected.getFoundDecl();
684 ND = getAsTemplateNameDecl(ND);
685 if (ND || Corrected.isKeyword()) {
687 std::string CorrectedStr(Corrected.getAsString(getLangOpts()));
688 bool DroppedSpecifier = Corrected.WillReplaceSpecifier() &&
689 Name.getAsString() == CorrectedStr;
690 diagnoseTypo(Corrected,
691 PDiag(diag::err_non_template_in_member_template_id_suggest)
692 << Name << LookupCtx << DroppedSpecifier
693 << SS.getRange(), false);
695 diagnoseTypo(Corrected,
696 PDiag(diag::err_non_template_in_template_id_suggest)
700 Diag(Found->getLocation(),
701 diag::note_non_template_in_template_id_found);
706 Diag(NameInfo.getLoc(), diag::err_non_template_in_template_id)
707 << Name << SourceRange(Less, Greater);
709 Diag(Found->getLocation(), diag::note_non_template_in_template_id_found);
712 /// ActOnDependentIdExpression - Handle a dependent id-expression that
713 /// was just parsed. This is only possible with an explicit scope
714 /// specifier naming a dependent type.
716 Sema::ActOnDependentIdExpression(const CXXScopeSpec &SS,
717 SourceLocation TemplateKWLoc,
718 const DeclarationNameInfo &NameInfo,
719 bool isAddressOfOperand,
720 const TemplateArgumentListInfo *TemplateArgs) {
721 DeclContext *DC = getFunctionLevelDeclContext();
723 // C++11 [expr.prim.general]p12:
724 // An id-expression that denotes a non-static data member or non-static
725 // member function of a class can only be used:
727 // - if that id-expression denotes a non-static data member and it
728 // appears in an unevaluated operand.
730 // If this might be the case, form a DependentScopeDeclRefExpr instead of a
731 // CXXDependentScopeMemberExpr. The former can instantiate to either
732 // DeclRefExpr or MemberExpr depending on lookup results, while the latter is
733 // always a MemberExpr.
734 bool MightBeCxx11UnevalField =
735 getLangOpts().CPlusPlus11 && isUnevaluatedContext();
737 // Check if the nested name specifier is an enum type.
739 if (NestedNameSpecifier *NNS = SS.getScopeRep())
740 IsEnum = dyn_cast_or_null<EnumType>(NNS->getAsType());
742 if (!MightBeCxx11UnevalField && !isAddressOfOperand && !IsEnum &&
743 isa<CXXMethodDecl>(DC) && cast<CXXMethodDecl>(DC)->isInstance()) {
744 QualType ThisType = cast<CXXMethodDecl>(DC)->getThisType();
746 // Since the 'this' expression is synthesized, we don't need to
747 // perform the double-lookup check.
748 NamedDecl *FirstQualifierInScope = nullptr;
750 return CXXDependentScopeMemberExpr::Create(
751 Context, /*This*/ nullptr, ThisType, /*IsArrow*/ true,
752 /*Op*/ SourceLocation(), SS.getWithLocInContext(Context), TemplateKWLoc,
753 FirstQualifierInScope, NameInfo, TemplateArgs);
756 return BuildDependentDeclRefExpr(SS, TemplateKWLoc, NameInfo, TemplateArgs);
760 Sema::BuildDependentDeclRefExpr(const CXXScopeSpec &SS,
761 SourceLocation TemplateKWLoc,
762 const DeclarationNameInfo &NameInfo,
763 const TemplateArgumentListInfo *TemplateArgs) {
764 // DependentScopeDeclRefExpr::Create requires a valid QualifierLoc
765 NestedNameSpecifierLoc QualifierLoc = SS.getWithLocInContext(Context);
769 return DependentScopeDeclRefExpr::Create(
770 Context, QualifierLoc, TemplateKWLoc, NameInfo, TemplateArgs);
774 /// Determine whether we would be unable to instantiate this template (because
775 /// it either has no definition, or is in the process of being instantiated).
776 bool Sema::DiagnoseUninstantiableTemplate(SourceLocation PointOfInstantiation,
777 NamedDecl *Instantiation,
778 bool InstantiatedFromMember,
779 const NamedDecl *Pattern,
780 const NamedDecl *PatternDef,
781 TemplateSpecializationKind TSK,
782 bool Complain /*= true*/) {
783 assert(isa<TagDecl>(Instantiation) || isa<FunctionDecl>(Instantiation) ||
784 isa<VarDecl>(Instantiation));
786 bool IsEntityBeingDefined = false;
787 if (const TagDecl *TD = dyn_cast_or_null<TagDecl>(PatternDef))
788 IsEntityBeingDefined = TD->isBeingDefined();
790 if (PatternDef && !IsEntityBeingDefined) {
791 NamedDecl *SuggestedDef = nullptr;
792 if (!hasVisibleDefinition(const_cast<NamedDecl*>(PatternDef), &SuggestedDef,
793 /*OnlyNeedComplete*/false)) {
794 // If we're allowed to diagnose this and recover, do so.
795 bool Recover = Complain && !isSFINAEContext();
797 diagnoseMissingImport(PointOfInstantiation, SuggestedDef,
798 Sema::MissingImportKind::Definition, Recover);
804 if (!Complain || (PatternDef && PatternDef->isInvalidDecl()))
807 llvm::Optional<unsigned> Note;
808 QualType InstantiationTy;
809 if (TagDecl *TD = dyn_cast<TagDecl>(Instantiation))
810 InstantiationTy = Context.getTypeDeclType(TD);
812 Diag(PointOfInstantiation,
813 diag::err_template_instantiate_within_definition)
814 << /*implicit|explicit*/(TSK != TSK_ImplicitInstantiation)
816 // Not much point in noting the template declaration here, since
817 // we're lexically inside it.
818 Instantiation->setInvalidDecl();
819 } else if (InstantiatedFromMember) {
820 if (isa<FunctionDecl>(Instantiation)) {
821 Diag(PointOfInstantiation,
822 diag::err_explicit_instantiation_undefined_member)
823 << /*member function*/ 1 << Instantiation->getDeclName()
824 << Instantiation->getDeclContext();
825 Note = diag::note_explicit_instantiation_here;
827 assert(isa<TagDecl>(Instantiation) && "Must be a TagDecl!");
828 Diag(PointOfInstantiation,
829 diag::err_implicit_instantiate_member_undefined)
831 Note = diag::note_member_declared_at;
834 if (isa<FunctionDecl>(Instantiation)) {
835 Diag(PointOfInstantiation,
836 diag::err_explicit_instantiation_undefined_func_template)
838 Note = diag::note_explicit_instantiation_here;
839 } else if (isa<TagDecl>(Instantiation)) {
840 Diag(PointOfInstantiation, diag::err_template_instantiate_undefined)
841 << (TSK != TSK_ImplicitInstantiation)
843 Note = diag::note_template_decl_here;
845 assert(isa<VarDecl>(Instantiation) && "Must be a VarDecl!");
846 if (isa<VarTemplateSpecializationDecl>(Instantiation)) {
847 Diag(PointOfInstantiation,
848 diag::err_explicit_instantiation_undefined_var_template)
850 Instantiation->setInvalidDecl();
852 Diag(PointOfInstantiation,
853 diag::err_explicit_instantiation_undefined_member)
854 << /*static data member*/ 2 << Instantiation->getDeclName()
855 << Instantiation->getDeclContext();
856 Note = diag::note_explicit_instantiation_here;
859 if (Note) // Diagnostics were emitted.
860 Diag(Pattern->getLocation(), Note.getValue());
862 // In general, Instantiation isn't marked invalid to get more than one
863 // error for multiple undefined instantiations. But the code that does
864 // explicit declaration -> explicit definition conversion can't handle
865 // invalid declarations, so mark as invalid in that case.
866 if (TSK == TSK_ExplicitInstantiationDeclaration)
867 Instantiation->setInvalidDecl();
871 /// DiagnoseTemplateParameterShadow - Produce a diagnostic complaining
872 /// that the template parameter 'PrevDecl' is being shadowed by a new
873 /// declaration at location Loc. Returns true to indicate that this is
874 /// an error, and false otherwise.
875 void Sema::DiagnoseTemplateParameterShadow(SourceLocation Loc, Decl *PrevDecl) {
876 assert(PrevDecl->isTemplateParameter() && "Not a template parameter");
878 // C++ [temp.local]p4:
879 // A template-parameter shall not be redeclared within its
880 // scope (including nested scopes).
882 // Make this a warning when MSVC compatibility is requested.
883 unsigned DiagId = getLangOpts().MSVCCompat ? diag::ext_template_param_shadow
884 : diag::err_template_param_shadow;
885 Diag(Loc, DiagId) << cast<NamedDecl>(PrevDecl)->getDeclName();
886 Diag(PrevDecl->getLocation(), diag::note_template_param_here);
889 /// AdjustDeclIfTemplate - If the given decl happens to be a template, reset
890 /// the parameter D to reference the templated declaration and return a pointer
891 /// to the template declaration. Otherwise, do nothing to D and return null.
892 TemplateDecl *Sema::AdjustDeclIfTemplate(Decl *&D) {
893 if (TemplateDecl *Temp = dyn_cast_or_null<TemplateDecl>(D)) {
894 D = Temp->getTemplatedDecl();
900 ParsedTemplateArgument ParsedTemplateArgument::getTemplatePackExpansion(
901 SourceLocation EllipsisLoc) const {
902 assert(Kind == Template &&
903 "Only template template arguments can be pack expansions here");
904 assert(getAsTemplate().get().containsUnexpandedParameterPack() &&
905 "Template template argument pack expansion without packs");
906 ParsedTemplateArgument Result(*this);
907 Result.EllipsisLoc = EllipsisLoc;
911 static TemplateArgumentLoc translateTemplateArgument(Sema &SemaRef,
912 const ParsedTemplateArgument &Arg) {
914 switch (Arg.getKind()) {
915 case ParsedTemplateArgument::Type: {
917 QualType T = SemaRef.GetTypeFromParser(Arg.getAsType(), &DI);
919 DI = SemaRef.Context.getTrivialTypeSourceInfo(T, Arg.getLocation());
920 return TemplateArgumentLoc(TemplateArgument(T), DI);
923 case ParsedTemplateArgument::NonType: {
924 Expr *E = static_cast<Expr *>(Arg.getAsExpr());
925 return TemplateArgumentLoc(TemplateArgument(E), E);
928 case ParsedTemplateArgument::Template: {
929 TemplateName Template = Arg.getAsTemplate().get();
930 TemplateArgument TArg;
931 if (Arg.getEllipsisLoc().isValid())
932 TArg = TemplateArgument(Template, Optional<unsigned int>());
935 return TemplateArgumentLoc(TArg,
936 Arg.getScopeSpec().getWithLocInContext(
939 Arg.getEllipsisLoc());
943 llvm_unreachable("Unhandled parsed template argument");
946 /// Translates template arguments as provided by the parser
947 /// into template arguments used by semantic analysis.
948 void Sema::translateTemplateArguments(const ASTTemplateArgsPtr &TemplateArgsIn,
949 TemplateArgumentListInfo &TemplateArgs) {
950 for (unsigned I = 0, Last = TemplateArgsIn.size(); I != Last; ++I)
951 TemplateArgs.addArgument(translateTemplateArgument(*this,
955 static void maybeDiagnoseTemplateParameterShadow(Sema &SemaRef, Scope *S,
957 IdentifierInfo *Name) {
958 NamedDecl *PrevDecl = SemaRef.LookupSingleName(
959 S, Name, Loc, Sema::LookupOrdinaryName, Sema::ForVisibleRedeclaration);
960 if (PrevDecl && PrevDecl->isTemplateParameter())
961 SemaRef.DiagnoseTemplateParameterShadow(Loc, PrevDecl);
964 /// Convert a parsed type into a parsed template argument. This is mostly
965 /// trivial, except that we may have parsed a C++17 deduced class template
966 /// specialization type, in which case we should form a template template
967 /// argument instead of a type template argument.
968 ParsedTemplateArgument Sema::ActOnTemplateTypeArgument(TypeResult ParsedType) {
969 TypeSourceInfo *TInfo;
970 QualType T = GetTypeFromParser(ParsedType.get(), &TInfo);
972 return ParsedTemplateArgument();
973 assert(TInfo && "template argument with no location");
975 // If we might have formed a deduced template specialization type, convert
976 // it to a template template argument.
977 if (getLangOpts().CPlusPlus17) {
978 TypeLoc TL = TInfo->getTypeLoc();
979 SourceLocation EllipsisLoc;
980 if (auto PET = TL.getAs<PackExpansionTypeLoc>()) {
981 EllipsisLoc = PET.getEllipsisLoc();
982 TL = PET.getPatternLoc();
986 if (auto ET = TL.getAs<ElaboratedTypeLoc>()) {
987 SS.Adopt(ET.getQualifierLoc());
988 TL = ET.getNamedTypeLoc();
991 if (auto DTST = TL.getAs<DeducedTemplateSpecializationTypeLoc>()) {
992 TemplateName Name = DTST.getTypePtr()->getTemplateName();
994 Name = Context.getQualifiedTemplateName(SS.getScopeRep(),
995 /*HasTemplateKeyword*/ false,
996 Name.getAsTemplateDecl());
997 ParsedTemplateArgument Result(SS, TemplateTy::make(Name),
998 DTST.getTemplateNameLoc());
999 if (EllipsisLoc.isValid())
1000 Result = Result.getTemplatePackExpansion(EllipsisLoc);
1005 // This is a normal type template argument. Note, if the type template
1006 // argument is an injected-class-name for a template, it has a dual nature
1007 // and can be used as either a type or a template. We handle that in
1008 // convertTypeTemplateArgumentToTemplate.
1009 return ParsedTemplateArgument(ParsedTemplateArgument::Type,
1010 ParsedType.get().getAsOpaquePtr(),
1011 TInfo->getTypeLoc().getBeginLoc());
1014 /// ActOnTypeParameter - Called when a C++ template type parameter
1015 /// (e.g., "typename T") has been parsed. Typename specifies whether
1016 /// the keyword "typename" was used to declare the type parameter
1017 /// (otherwise, "class" was used), and KeyLoc is the location of the
1018 /// "class" or "typename" keyword. ParamName is the name of the
1019 /// parameter (NULL indicates an unnamed template parameter) and
1020 /// ParamNameLoc is the location of the parameter name (if any).
1021 /// If the type parameter has a default argument, it will be added
1022 /// later via ActOnTypeParameterDefault.
1023 NamedDecl *Sema::ActOnTypeParameter(Scope *S, bool Typename,
1024 SourceLocation EllipsisLoc,
1025 SourceLocation KeyLoc,
1026 IdentifierInfo *ParamName,
1027 SourceLocation ParamNameLoc,
1028 unsigned Depth, unsigned Position,
1029 SourceLocation EqualLoc,
1030 ParsedType DefaultArg,
1031 bool HasTypeConstraint) {
1032 assert(S->isTemplateParamScope() &&
1033 "Template type parameter not in template parameter scope!");
1035 bool IsParameterPack = EllipsisLoc.isValid();
1036 TemplateTypeParmDecl *Param
1037 = TemplateTypeParmDecl::Create(Context, Context.getTranslationUnitDecl(),
1038 KeyLoc, ParamNameLoc, Depth, Position,
1039 ParamName, Typename, IsParameterPack,
1041 Param->setAccess(AS_public);
1043 if (Param->isParameterPack())
1044 if (auto *LSI = getEnclosingLambda())
1045 LSI->LocalPacks.push_back(Param);
1048 maybeDiagnoseTemplateParameterShadow(*this, S, ParamNameLoc, ParamName);
1050 // Add the template parameter into the current scope.
1052 IdResolver.AddDecl(Param);
1055 // C++0x [temp.param]p9:
1056 // A default template-argument may be specified for any kind of
1057 // template-parameter that is not a template parameter pack.
1058 if (DefaultArg && IsParameterPack) {
1059 Diag(EqualLoc, diag::err_template_param_pack_default_arg);
1060 DefaultArg = nullptr;
1063 // Handle the default argument, if provided.
1065 TypeSourceInfo *DefaultTInfo;
1066 GetTypeFromParser(DefaultArg, &DefaultTInfo);
1068 assert(DefaultTInfo && "expected source information for type");
1070 // Check for unexpanded parameter packs.
1071 if (DiagnoseUnexpandedParameterPack(ParamNameLoc, DefaultTInfo,
1072 UPPC_DefaultArgument))
1075 // Check the template argument itself.
1076 if (CheckTemplateArgument(Param, DefaultTInfo)) {
1077 Param->setInvalidDecl();
1081 Param->setDefaultArgument(DefaultTInfo);
1087 /// Convert the parser's template argument list representation into our form.
1088 static TemplateArgumentListInfo
1089 makeTemplateArgumentListInfo(Sema &S, TemplateIdAnnotation &TemplateId) {
1090 TemplateArgumentListInfo TemplateArgs(TemplateId.LAngleLoc,
1091 TemplateId.RAngleLoc);
1092 ASTTemplateArgsPtr TemplateArgsPtr(TemplateId.getTemplateArgs(),
1093 TemplateId.NumArgs);
1094 S.translateTemplateArguments(TemplateArgsPtr, TemplateArgs);
1095 return TemplateArgs;
1098 bool Sema::ActOnTypeConstraint(const CXXScopeSpec &SS,
1099 TemplateIdAnnotation *TypeConstr,
1100 TemplateTypeParmDecl *ConstrainedParameter,
1101 SourceLocation EllipsisLoc) {
1103 cast<ConceptDecl>(TypeConstr->Template.get().getAsTemplateDecl());
1105 // C++2a [temp.param]p4:
1106 // [...] The concept designated by a type-constraint shall be a type
1107 // concept ([temp.concept]).
1108 if (!CD->isTypeConcept()) {
1109 Diag(TypeConstr->TemplateNameLoc,
1110 diag::err_type_constraint_non_type_concept);
1114 bool WereArgsSpecified = TypeConstr->LAngleLoc.isValid();
1116 if (!WereArgsSpecified &&
1117 CD->getTemplateParameters()->getMinRequiredArguments() > 1) {
1118 Diag(TypeConstr->TemplateNameLoc,
1119 diag::err_type_constraint_missing_arguments) << CD;
1123 TemplateArgumentListInfo TemplateArgs;
1124 if (TypeConstr->LAngleLoc.isValid()) {
1126 makeTemplateArgumentListInfo(*this, *TypeConstr);
1128 return AttachTypeConstraint(
1129 SS.isSet() ? SS.getWithLocInContext(Context) : NestedNameSpecifierLoc(),
1130 DeclarationNameInfo(DeclarationName(TypeConstr->Name),
1131 TypeConstr->TemplateNameLoc), CD,
1132 TypeConstr->LAngleLoc.isValid() ? &TemplateArgs : nullptr,
1133 ConstrainedParameter, EllipsisLoc);
1136 template<typename ArgumentLocAppender>
1137 static ExprResult formImmediatelyDeclaredConstraint(
1138 Sema &S, NestedNameSpecifierLoc NS, DeclarationNameInfo NameInfo,
1139 ConceptDecl *NamedConcept, SourceLocation LAngleLoc,
1140 SourceLocation RAngleLoc, QualType ConstrainedType,
1141 SourceLocation ParamNameLoc, ArgumentLocAppender Appender,
1142 SourceLocation EllipsisLoc) {
1144 TemplateArgumentListInfo ConstraintArgs;
1145 ConstraintArgs.addArgument(
1146 S.getTrivialTemplateArgumentLoc(TemplateArgument(ConstrainedType),
1147 /*NTTPType=*/QualType(), ParamNameLoc));
1149 ConstraintArgs.setRAngleLoc(RAngleLoc);
1150 ConstraintArgs.setLAngleLoc(LAngleLoc);
1151 Appender(ConstraintArgs);
1153 // C++2a [temp.param]p4:
1154 // [...] This constraint-expression E is called the immediately-declared
1155 // constraint of T. [...]
1158 ExprResult ImmediatelyDeclaredConstraint = S.CheckConceptTemplateId(
1159 SS, /*TemplateKWLoc=*/SourceLocation(), NameInfo,
1160 /*FoundDecl=*/NamedConcept, NamedConcept, &ConstraintArgs);
1161 if (ImmediatelyDeclaredConstraint.isInvalid() || !EllipsisLoc.isValid())
1162 return ImmediatelyDeclaredConstraint;
1164 // C++2a [temp.param]p4:
1165 // [...] If T is not a pack, then E is E', otherwise E is (E' && ...).
1167 // We have the following case:
1169 // template<typename T> concept C1 = true;
1170 // template<C1... T> struct s1;
1172 // The constraint: (C1<T> && ...)
1173 return S.BuildCXXFoldExpr(/*LParenLoc=*/SourceLocation(),
1174 ImmediatelyDeclaredConstraint.get(), BO_LAnd,
1175 EllipsisLoc, /*RHS=*/nullptr,
1176 /*RParenLoc=*/SourceLocation(),
1177 /*NumExpansions=*/None);
1180 /// Attach a type-constraint to a template parameter.
1181 /// \returns true if an error occured. This can happen if the
1182 /// immediately-declared constraint could not be formed (e.g. incorrect number
1183 /// of arguments for the named concept).
1184 bool Sema::AttachTypeConstraint(NestedNameSpecifierLoc NS,
1185 DeclarationNameInfo NameInfo,
1186 ConceptDecl *NamedConcept,
1187 const TemplateArgumentListInfo *TemplateArgs,
1188 TemplateTypeParmDecl *ConstrainedParameter,
1189 SourceLocation EllipsisLoc) {
1190 // C++2a [temp.param]p4:
1191 // [...] If Q is of the form C<A1, ..., An>, then let E' be
1192 // C<T, A1, ..., An>. Otherwise, let E' be C<T>. [...]
1193 const ASTTemplateArgumentListInfo *ArgsAsWritten =
1194 TemplateArgs ? ASTTemplateArgumentListInfo::Create(Context,
1195 *TemplateArgs) : nullptr;
1197 QualType ParamAsArgument(ConstrainedParameter->getTypeForDecl(), 0);
1199 ExprResult ImmediatelyDeclaredConstraint =
1200 formImmediatelyDeclaredConstraint(
1201 *this, NS, NameInfo, NamedConcept,
1202 TemplateArgs ? TemplateArgs->getLAngleLoc() : SourceLocation(),
1203 TemplateArgs ? TemplateArgs->getRAngleLoc() : SourceLocation(),
1204 ParamAsArgument, ConstrainedParameter->getLocation(),
1205 [&] (TemplateArgumentListInfo &ConstraintArgs) {
1207 for (const auto &ArgLoc : TemplateArgs->arguments())
1208 ConstraintArgs.addArgument(ArgLoc);
1210 if (ImmediatelyDeclaredConstraint.isInvalid())
1213 ConstrainedParameter->setTypeConstraint(NS, NameInfo,
1214 /*FoundDecl=*/NamedConcept,
1215 NamedConcept, ArgsAsWritten,
1216 ImmediatelyDeclaredConstraint.get());
1220 bool Sema::AttachTypeConstraint(AutoTypeLoc TL, NonTypeTemplateParmDecl *NTTP,
1221 SourceLocation EllipsisLoc) {
1222 if (NTTP->getType() != TL.getType() ||
1223 TL.getAutoKeyword() != AutoTypeKeyword::Auto) {
1224 Diag(NTTP->getTypeSourceInfo()->getTypeLoc().getBeginLoc(),
1225 diag::err_unsupported_placeholder_constraint)
1226 << NTTP->getTypeSourceInfo()->getTypeLoc().getSourceRange();
1229 // FIXME: Concepts: This should be the type of the placeholder, but this is
1230 // unclear in the wording right now.
1231 DeclRefExpr *Ref = BuildDeclRefExpr(NTTP, NTTP->getType(), VK_RValue,
1232 NTTP->getLocation());
1235 ExprResult ImmediatelyDeclaredConstraint =
1236 formImmediatelyDeclaredConstraint(
1237 *this, TL.getNestedNameSpecifierLoc(), TL.getConceptNameInfo(),
1238 TL.getNamedConcept(), TL.getLAngleLoc(), TL.getRAngleLoc(),
1239 BuildDecltypeType(Ref, NTTP->getLocation()), NTTP->getLocation(),
1240 [&] (TemplateArgumentListInfo &ConstraintArgs) {
1241 for (unsigned I = 0, C = TL.getNumArgs(); I != C; ++I)
1242 ConstraintArgs.addArgument(TL.getArgLoc(I));
1244 if (ImmediatelyDeclaredConstraint.isInvalid() ||
1245 !ImmediatelyDeclaredConstraint.isUsable())
1248 NTTP->setPlaceholderTypeConstraint(ImmediatelyDeclaredConstraint.get());
1252 /// Check that the type of a non-type template parameter is
1255 /// \returns the (possibly-promoted) parameter type if valid;
1256 /// otherwise, produces a diagnostic and returns a NULL type.
1257 QualType Sema::CheckNonTypeTemplateParameterType(TypeSourceInfo *&TSI,
1258 SourceLocation Loc) {
1259 if (TSI->getType()->isUndeducedType()) {
1260 // C++17 [temp.dep.expr]p3:
1261 // An id-expression is type-dependent if it contains
1262 // - an identifier associated by name lookup with a non-type
1263 // template-parameter declared with a type that contains a
1264 // placeholder type (7.1.7.4),
1265 TSI = SubstAutoTypeSourceInfo(TSI, Context.DependentTy);
1268 return CheckNonTypeTemplateParameterType(TSI->getType(), Loc);
1271 QualType Sema::CheckNonTypeTemplateParameterType(QualType T,
1272 SourceLocation Loc) {
1273 // We don't allow variably-modified types as the type of non-type template
1275 if (T->isVariablyModifiedType()) {
1276 Diag(Loc, diag::err_variably_modified_nontype_template_param)
1281 // C++ [temp.param]p4:
1283 // A non-type template-parameter shall have one of the following
1284 // (optionally cv-qualified) types:
1286 // -- integral or enumeration type,
1287 if (T->isIntegralOrEnumerationType() ||
1288 // -- pointer to object or pointer to function,
1289 T->isPointerType() ||
1290 // -- reference to object or reference to function,
1291 T->isReferenceType() ||
1292 // -- pointer to member,
1293 T->isMemberPointerType() ||
1294 // -- std::nullptr_t.
1295 T->isNullPtrType() ||
1296 // Allow use of auto in template parameter declarations.
1297 T->isUndeducedType()) {
1298 // C++ [temp.param]p5: The top-level cv-qualifiers on the template-parameter
1299 // are ignored when determining its type.
1300 return T.getUnqualifiedType();
1303 // C++ [temp.param]p8:
1305 // A non-type template-parameter of type "array of T" or
1306 // "function returning T" is adjusted to be of type "pointer to
1307 // T" or "pointer to function returning T", respectively.
1308 if (T->isArrayType() || T->isFunctionType())
1309 return Context.getDecayedType(T);
1311 // If T is a dependent type, we can't do the check now, so we
1312 // assume that it is well-formed. Note that stripping off the
1313 // qualifiers here is not really correct if T turns out to be
1314 // an array type, but we'll recompute the type everywhere it's
1315 // used during instantiation, so that should be OK. (Using the
1316 // qualified type is equally wrong.)
1317 if (T->isDependentType())
1318 return T.getUnqualifiedType();
1320 Diag(Loc, diag::err_template_nontype_parm_bad_type)
1326 NamedDecl *Sema::ActOnNonTypeTemplateParameter(Scope *S, Declarator &D,
1329 SourceLocation EqualLoc,
1331 TypeSourceInfo *TInfo = GetTypeForDeclarator(D, S);
1333 // Check that we have valid decl-specifiers specified.
1334 auto CheckValidDeclSpecifiers = [this, &D] {
1337 // template-parameter:
1339 // parameter-declaration
1341 // ... A storage class shall not be specified in a template-parameter
1344 // The typedef specifier [...] shall not be used in the decl-specifier-seq
1345 // of a parameter-declaration
1346 const DeclSpec &DS = D.getDeclSpec();
1347 auto EmitDiag = [this](SourceLocation Loc) {
1348 Diag(Loc, diag::err_invalid_decl_specifier_in_nontype_parm)
1349 << FixItHint::CreateRemoval(Loc);
1351 if (DS.getStorageClassSpec() != DeclSpec::SCS_unspecified)
1352 EmitDiag(DS.getStorageClassSpecLoc());
1354 if (DS.getThreadStorageClassSpec() != TSCS_unspecified)
1355 EmitDiag(DS.getThreadStorageClassSpecLoc());
1358 // The inline specifier can be applied only to the declaration or
1359 // definition of a variable or function.
1361 if (DS.isInlineSpecified())
1362 EmitDiag(DS.getInlineSpecLoc());
1364 // [dcl.constexpr]p1:
1365 // The constexpr specifier shall be applied only to the definition of a
1366 // variable or variable template or the declaration of a function or
1367 // function template.
1369 if (DS.hasConstexprSpecifier())
1370 EmitDiag(DS.getConstexprSpecLoc());
1372 // [dcl.fct.spec]p1:
1373 // Function-specifiers can be used only in function declarations.
1375 if (DS.isVirtualSpecified())
1376 EmitDiag(DS.getVirtualSpecLoc());
1378 if (DS.hasExplicitSpecifier())
1379 EmitDiag(DS.getExplicitSpecLoc());
1381 if (DS.isNoreturnSpecified())
1382 EmitDiag(DS.getNoreturnSpecLoc());
1385 CheckValidDeclSpecifiers();
1387 if (TInfo->getType()->isUndeducedType()) {
1388 Diag(D.getIdentifierLoc(),
1389 diag::warn_cxx14_compat_template_nontype_parm_auto_type)
1390 << QualType(TInfo->getType()->getContainedAutoType(), 0);
1393 assert(S->isTemplateParamScope() &&
1394 "Non-type template parameter not in template parameter scope!");
1395 bool Invalid = false;
1397 QualType T = CheckNonTypeTemplateParameterType(TInfo, D.getIdentifierLoc());
1399 T = Context.IntTy; // Recover with an 'int' type.
1403 CheckFunctionOrTemplateParamDeclarator(S, D);
1405 IdentifierInfo *ParamName = D.getIdentifier();
1406 bool IsParameterPack = D.hasEllipsis();
1407 NonTypeTemplateParmDecl *Param = NonTypeTemplateParmDecl::Create(
1408 Context, Context.getTranslationUnitDecl(), D.getBeginLoc(),
1409 D.getIdentifierLoc(), Depth, Position, ParamName, T, IsParameterPack,
1411 Param->setAccess(AS_public);
1413 if (AutoTypeLoc TL = TInfo->getTypeLoc().getContainedAutoTypeLoc())
1414 if (TL.isConstrained())
1415 if (AttachTypeConstraint(TL, Param, D.getEllipsisLoc()))
1419 Param->setInvalidDecl();
1421 if (Param->isParameterPack())
1422 if (auto *LSI = getEnclosingLambda())
1423 LSI->LocalPacks.push_back(Param);
1426 maybeDiagnoseTemplateParameterShadow(*this, S, D.getIdentifierLoc(),
1429 // Add the template parameter into the current scope.
1431 IdResolver.AddDecl(Param);
1434 // C++0x [temp.param]p9:
1435 // A default template-argument may be specified for any kind of
1436 // template-parameter that is not a template parameter pack.
1437 if (Default && IsParameterPack) {
1438 Diag(EqualLoc, diag::err_template_param_pack_default_arg);
1442 // Check the well-formedness of the default template argument, if provided.
1444 // Check for unexpanded parameter packs.
1445 if (DiagnoseUnexpandedParameterPack(Default, UPPC_DefaultArgument))
1448 TemplateArgument Converted;
1449 ExprResult DefaultRes =
1450 CheckTemplateArgument(Param, Param->getType(), Default, Converted);
1451 if (DefaultRes.isInvalid()) {
1452 Param->setInvalidDecl();
1455 Default = DefaultRes.get();
1457 Param->setDefaultArgument(Default);
1463 /// ActOnTemplateTemplateParameter - Called when a C++ template template
1464 /// parameter (e.g. T in template <template \<typename> class T> class array)
1465 /// has been parsed. S is the current scope.
1466 NamedDecl *Sema::ActOnTemplateTemplateParameter(Scope* S,
1467 SourceLocation TmpLoc,
1468 TemplateParameterList *Params,
1469 SourceLocation EllipsisLoc,
1470 IdentifierInfo *Name,
1471 SourceLocation NameLoc,
1474 SourceLocation EqualLoc,
1475 ParsedTemplateArgument Default) {
1476 assert(S->isTemplateParamScope() &&
1477 "Template template parameter not in template parameter scope!");
1479 // Construct the parameter object.
1480 bool IsParameterPack = EllipsisLoc.isValid();
1481 TemplateTemplateParmDecl *Param =
1482 TemplateTemplateParmDecl::Create(Context, Context.getTranslationUnitDecl(),
1483 NameLoc.isInvalid()? TmpLoc : NameLoc,
1484 Depth, Position, IsParameterPack,
1486 Param->setAccess(AS_public);
1488 if (Param->isParameterPack())
1489 if (auto *LSI = getEnclosingLambda())
1490 LSI->LocalPacks.push_back(Param);
1492 // If the template template parameter has a name, then link the identifier
1493 // into the scope and lookup mechanisms.
1495 maybeDiagnoseTemplateParameterShadow(*this, S, NameLoc, Name);
1498 IdResolver.AddDecl(Param);
1501 if (Params->size() == 0) {
1502 Diag(Param->getLocation(), diag::err_template_template_parm_no_parms)
1503 << SourceRange(Params->getLAngleLoc(), Params->getRAngleLoc());
1504 Param->setInvalidDecl();
1507 // C++0x [temp.param]p9:
1508 // A default template-argument may be specified for any kind of
1509 // template-parameter that is not a template parameter pack.
1510 if (IsParameterPack && !Default.isInvalid()) {
1511 Diag(EqualLoc, diag::err_template_param_pack_default_arg);
1512 Default = ParsedTemplateArgument();
1515 if (!Default.isInvalid()) {
1516 // Check only that we have a template template argument. We don't want to
1517 // try to check well-formedness now, because our template template parameter
1518 // might have dependent types in its template parameters, which we wouldn't
1519 // be able to match now.
1521 // If none of the template template parameter's template arguments mention
1522 // other template parameters, we could actually perform more checking here.
1523 // However, it isn't worth doing.
1524 TemplateArgumentLoc DefaultArg = translateTemplateArgument(*this, Default);
1525 if (DefaultArg.getArgument().getAsTemplate().isNull()) {
1526 Diag(DefaultArg.getLocation(), diag::err_template_arg_not_valid_template)
1527 << DefaultArg.getSourceRange();
1531 // Check for unexpanded parameter packs.
1532 if (DiagnoseUnexpandedParameterPack(DefaultArg.getLocation(),
1533 DefaultArg.getArgument().getAsTemplate(),
1534 UPPC_DefaultArgument))
1537 Param->setDefaultArgument(Context, DefaultArg);
1543 /// ActOnTemplateParameterList - Builds a TemplateParameterList, optionally
1544 /// constrained by RequiresClause, that contains the template parameters in
1546 TemplateParameterList *
1547 Sema::ActOnTemplateParameterList(unsigned Depth,
1548 SourceLocation ExportLoc,
1549 SourceLocation TemplateLoc,
1550 SourceLocation LAngleLoc,
1551 ArrayRef<NamedDecl *> Params,
1552 SourceLocation RAngleLoc,
1553 Expr *RequiresClause) {
1554 if (ExportLoc.isValid())
1555 Diag(ExportLoc, diag::warn_template_export_unsupported);
1557 return TemplateParameterList::Create(
1558 Context, TemplateLoc, LAngleLoc,
1559 llvm::makeArrayRef(Params.data(), Params.size()),
1560 RAngleLoc, RequiresClause);
1563 static void SetNestedNameSpecifier(Sema &S, TagDecl *T,
1564 const CXXScopeSpec &SS) {
1566 T->setQualifierInfo(SS.getWithLocInContext(S.Context));
1569 DeclResult Sema::CheckClassTemplate(
1570 Scope *S, unsigned TagSpec, TagUseKind TUK, SourceLocation KWLoc,
1571 CXXScopeSpec &SS, IdentifierInfo *Name, SourceLocation NameLoc,
1572 const ParsedAttributesView &Attr, TemplateParameterList *TemplateParams,
1573 AccessSpecifier AS, SourceLocation ModulePrivateLoc,
1574 SourceLocation FriendLoc, unsigned NumOuterTemplateParamLists,
1575 TemplateParameterList **OuterTemplateParamLists, SkipBodyInfo *SkipBody) {
1576 assert(TemplateParams && TemplateParams->size() > 0 &&
1577 "No template parameters");
1578 assert(TUK != TUK_Reference && "Can only declare or define class templates");
1579 bool Invalid = false;
1581 // Check that we can declare a template here.
1582 if (CheckTemplateDeclScope(S, TemplateParams))
1585 TagTypeKind Kind = TypeWithKeyword::getTagTypeKindForTypeSpec(TagSpec);
1586 assert(Kind != TTK_Enum && "can't build template of enumerated type");
1588 // There is no such thing as an unnamed class template.
1590 Diag(KWLoc, diag::err_template_unnamed_class);
1594 // Find any previous declaration with this name. For a friend with no
1595 // scope explicitly specified, we only look for tag declarations (per
1596 // C++11 [basic.lookup.elab]p2).
1597 DeclContext *SemanticContext;
1598 LookupResult Previous(*this, Name, NameLoc,
1599 (SS.isEmpty() && TUK == TUK_Friend)
1600 ? LookupTagName : LookupOrdinaryName,
1601 forRedeclarationInCurContext());
1602 if (SS.isNotEmpty() && !SS.isInvalid()) {
1603 SemanticContext = computeDeclContext(SS, true);
1604 if (!SemanticContext) {
1605 // FIXME: Horrible, horrible hack! We can't currently represent this
1606 // in the AST, and historically we have just ignored such friend
1607 // class templates, so don't complain here.
1608 Diag(NameLoc, TUK == TUK_Friend
1609 ? diag::warn_template_qualified_friend_ignored
1610 : diag::err_template_qualified_declarator_no_match)
1611 << SS.getScopeRep() << SS.getRange();
1612 return TUK != TUK_Friend;
1615 if (RequireCompleteDeclContext(SS, SemanticContext))
1618 // If we're adding a template to a dependent context, we may need to
1619 // rebuilding some of the types used within the template parameter list,
1620 // now that we know what the current instantiation is.
1621 if (SemanticContext->isDependentContext()) {
1622 ContextRAII SavedContext(*this, SemanticContext);
1623 if (RebuildTemplateParamsInCurrentInstantiation(TemplateParams))
1625 } else if (TUK != TUK_Friend && TUK != TUK_Reference)
1626 diagnoseQualifiedDeclaration(SS, SemanticContext, Name, NameLoc, false);
1628 LookupQualifiedName(Previous, SemanticContext);
1630 SemanticContext = CurContext;
1632 // C++14 [class.mem]p14:
1633 // If T is the name of a class, then each of the following shall have a
1634 // name different from T:
1635 // -- every member template of class T
1636 if (TUK != TUK_Friend &&
1637 DiagnoseClassNameShadow(SemanticContext,
1638 DeclarationNameInfo(Name, NameLoc)))
1641 LookupName(Previous, S);
1644 if (Previous.isAmbiguous())
1647 NamedDecl *PrevDecl = nullptr;
1648 if (Previous.begin() != Previous.end())
1649 PrevDecl = (*Previous.begin())->getUnderlyingDecl();
1651 if (PrevDecl && PrevDecl->isTemplateParameter()) {
1652 // Maybe we will complain about the shadowed template parameter.
1653 DiagnoseTemplateParameterShadow(NameLoc, PrevDecl);
1654 // Just pretend that we didn't see the previous declaration.
1658 // If there is a previous declaration with the same name, check
1659 // whether this is a valid redeclaration.
1660 ClassTemplateDecl *PrevClassTemplate =
1661 dyn_cast_or_null<ClassTemplateDecl>(PrevDecl);
1663 // We may have found the injected-class-name of a class template,
1664 // class template partial specialization, or class template specialization.
1665 // In these cases, grab the template that is being defined or specialized.
1666 if (!PrevClassTemplate && PrevDecl && isa<CXXRecordDecl>(PrevDecl) &&
1667 cast<CXXRecordDecl>(PrevDecl)->isInjectedClassName()) {
1668 PrevDecl = cast<CXXRecordDecl>(PrevDecl->getDeclContext());
1670 = cast<CXXRecordDecl>(PrevDecl)->getDescribedClassTemplate();
1671 if (!PrevClassTemplate && isa<ClassTemplateSpecializationDecl>(PrevDecl)) {
1673 = cast<ClassTemplateSpecializationDecl>(PrevDecl)
1674 ->getSpecializedTemplate();
1678 if (TUK == TUK_Friend) {
1679 // C++ [namespace.memdef]p3:
1680 // [...] When looking for a prior declaration of a class or a function
1681 // declared as a friend, and when the name of the friend class or
1682 // function is neither a qualified name nor a template-id, scopes outside
1683 // the innermost enclosing namespace scope are not considered.
1685 DeclContext *OutermostContext = CurContext;
1686 while (!OutermostContext->isFileContext())
1687 OutermostContext = OutermostContext->getLookupParent();
1690 (OutermostContext->Equals(PrevDecl->getDeclContext()) ||
1691 OutermostContext->Encloses(PrevDecl->getDeclContext()))) {
1692 SemanticContext = PrevDecl->getDeclContext();
1694 // Declarations in outer scopes don't matter. However, the outermost
1695 // context we computed is the semantic context for our new
1697 PrevDecl = PrevClassTemplate = nullptr;
1698 SemanticContext = OutermostContext;
1700 // Check that the chosen semantic context doesn't already contain a
1701 // declaration of this name as a non-tag type.
1702 Previous.clear(LookupOrdinaryName);
1703 DeclContext *LookupContext = SemanticContext;
1704 while (LookupContext->isTransparentContext())
1705 LookupContext = LookupContext->getLookupParent();
1706 LookupQualifiedName(Previous, LookupContext);
1708 if (Previous.isAmbiguous())
1711 if (Previous.begin() != Previous.end())
1712 PrevDecl = (*Previous.begin())->getUnderlyingDecl();
1715 } else if (PrevDecl &&
1716 !isDeclInScope(Previous.getRepresentativeDecl(), SemanticContext,
1718 PrevDecl = PrevClassTemplate = nullptr;
1720 if (auto *Shadow = dyn_cast_or_null<UsingShadowDecl>(
1721 PrevDecl ? Previous.getRepresentativeDecl() : nullptr)) {
1723 !(PrevClassTemplate &&
1724 PrevClassTemplate->getDeclContext()->getRedeclContext()->Equals(
1725 SemanticContext->getRedeclContext()))) {
1726 Diag(KWLoc, diag::err_using_decl_conflict_reverse);
1727 Diag(Shadow->getTargetDecl()->getLocation(),
1728 diag::note_using_decl_target);
1729 Diag(Shadow->getUsingDecl()->getLocation(), diag::note_using_decl) << 0;
1730 // Recover by ignoring the old declaration.
1731 PrevDecl = PrevClassTemplate = nullptr;
1735 if (PrevClassTemplate) {
1736 // Ensure that the template parameter lists are compatible. Skip this check
1737 // for a friend in a dependent context: the template parameter list itself
1738 // could be dependent.
1739 if (!(TUK == TUK_Friend && CurContext->isDependentContext()) &&
1740 !TemplateParameterListsAreEqual(TemplateParams,
1741 PrevClassTemplate->getTemplateParameters(),
1746 // C++ [temp.class]p4:
1747 // In a redeclaration, partial specialization, explicit
1748 // specialization or explicit instantiation of a class template,
1749 // the class-key shall agree in kind with the original class
1750 // template declaration (7.1.5.3).
1751 RecordDecl *PrevRecordDecl = PrevClassTemplate->getTemplatedDecl();
1752 if (!isAcceptableTagRedeclaration(PrevRecordDecl, Kind,
1753 TUK == TUK_Definition, KWLoc, Name)) {
1754 Diag(KWLoc, diag::err_use_with_wrong_tag)
1756 << FixItHint::CreateReplacement(KWLoc, PrevRecordDecl->getKindName());
1757 Diag(PrevRecordDecl->getLocation(), diag::note_previous_use);
1758 Kind = PrevRecordDecl->getTagKind();
1761 // Check for redefinition of this class template.
1762 if (TUK == TUK_Definition) {
1763 if (TagDecl *Def = PrevRecordDecl->getDefinition()) {
1764 // If we have a prior definition that is not visible, treat this as
1765 // simply making that previous definition visible.
1766 NamedDecl *Hidden = nullptr;
1767 if (SkipBody && !hasVisibleDefinition(Def, &Hidden)) {
1768 SkipBody->ShouldSkip = true;
1769 SkipBody->Previous = Def;
1770 auto *Tmpl = cast<CXXRecordDecl>(Hidden)->getDescribedClassTemplate();
1771 assert(Tmpl && "original definition of a class template is not a "
1773 makeMergedDefinitionVisible(Hidden);
1774 makeMergedDefinitionVisible(Tmpl);
1776 Diag(NameLoc, diag::err_redefinition) << Name;
1777 Diag(Def->getLocation(), diag::note_previous_definition);
1778 // FIXME: Would it make sense to try to "forget" the previous
1779 // definition, as part of error recovery?
1784 } else if (PrevDecl) {
1786 // A class template shall not have the same name as any other
1787 // template, class, function, object, enumeration, enumerator,
1788 // namespace, or type in the same scope (3.3), except as specified
1790 Diag(NameLoc, diag::err_redefinition_different_kind) << Name;
1791 Diag(PrevDecl->getLocation(), diag::note_previous_definition);
1795 // Check the template parameter list of this declaration, possibly
1796 // merging in the template parameter list from the previous class
1797 // template declaration. Skip this check for a friend in a dependent
1798 // context, because the template parameter list might be dependent.
1799 if (!(TUK == TUK_Friend && CurContext->isDependentContext()) &&
1800 CheckTemplateParameterList(
1803 ? PrevClassTemplate->getMostRecentDecl()->getTemplateParameters()
1805 (SS.isSet() && SemanticContext && SemanticContext->isRecord() &&
1806 SemanticContext->isDependentContext())
1807 ? TPC_ClassTemplateMember
1808 : TUK == TUK_Friend ? TPC_FriendClassTemplate : TPC_ClassTemplate,
1813 // If the name of the template was qualified, we must be defining the
1814 // template out-of-line.
1815 if (!SS.isInvalid() && !Invalid && !PrevClassTemplate) {
1816 Diag(NameLoc, TUK == TUK_Friend ? diag::err_friend_decl_does_not_match
1817 : diag::err_member_decl_does_not_match)
1818 << Name << SemanticContext << /*IsDefinition*/true << SS.getRange();
1823 // If this is a templated friend in a dependent context we should not put it
1824 // on the redecl chain. In some cases, the templated friend can be the most
1825 // recent declaration tricking the template instantiator to make substitutions
1827 // FIXME: Figure out how to combine with shouldLinkDependentDeclWithPrevious
1828 bool ShouldAddRedecl
1829 = !(TUK == TUK_Friend && CurContext->isDependentContext());
1831 CXXRecordDecl *NewClass =
1832 CXXRecordDecl::Create(Context, Kind, SemanticContext, KWLoc, NameLoc, Name,
1833 PrevClassTemplate && ShouldAddRedecl ?
1834 PrevClassTemplate->getTemplatedDecl() : nullptr,
1835 /*DelayTypeCreation=*/true);
1836 SetNestedNameSpecifier(*this, NewClass, SS);
1837 if (NumOuterTemplateParamLists > 0)
1838 NewClass->setTemplateParameterListsInfo(
1839 Context, llvm::makeArrayRef(OuterTemplateParamLists,
1840 NumOuterTemplateParamLists));
1842 // Add alignment attributes if necessary; these attributes are checked when
1843 // the ASTContext lays out the structure.
1844 if (TUK == TUK_Definition && (!SkipBody || !SkipBody->ShouldSkip)) {
1845 AddAlignmentAttributesForRecord(NewClass);
1846 AddMsStructLayoutForRecord(NewClass);
1849 ClassTemplateDecl *NewTemplate
1850 = ClassTemplateDecl::Create(Context, SemanticContext, NameLoc,
1851 DeclarationName(Name), TemplateParams,
1854 if (ShouldAddRedecl)
1855 NewTemplate->setPreviousDecl(PrevClassTemplate);
1857 NewClass->setDescribedClassTemplate(NewTemplate);
1859 if (ModulePrivateLoc.isValid())
1860 NewTemplate->setModulePrivate();
1862 // Build the type for the class template declaration now.
1863 QualType T = NewTemplate->getInjectedClassNameSpecialization();
1864 T = Context.getInjectedClassNameType(NewClass, T);
1865 assert(T->isDependentType() && "Class template type is not dependent?");
1868 // If we are providing an explicit specialization of a member that is a
1869 // class template, make a note of that.
1870 if (PrevClassTemplate &&
1871 PrevClassTemplate->getInstantiatedFromMemberTemplate())
1872 PrevClassTemplate->setMemberSpecialization();
1874 // Set the access specifier.
1875 if (!Invalid && TUK != TUK_Friend && NewTemplate->getDeclContext()->isRecord())
1876 SetMemberAccessSpecifier(NewTemplate, PrevClassTemplate, AS);
1878 // Set the lexical context of these templates
1879 NewClass->setLexicalDeclContext(CurContext);
1880 NewTemplate->setLexicalDeclContext(CurContext);
1882 if (TUK == TUK_Definition && (!SkipBody || !SkipBody->ShouldSkip))
1883 NewClass->startDefinition();
1885 ProcessDeclAttributeList(S, NewClass, Attr);
1887 if (PrevClassTemplate)
1888 mergeDeclAttributes(NewClass, PrevClassTemplate->getTemplatedDecl());
1890 AddPushedVisibilityAttribute(NewClass);
1891 inferGslOwnerPointerAttribute(NewClass);
1893 if (TUK != TUK_Friend) {
1894 // Per C++ [basic.scope.temp]p2, skip the template parameter scopes.
1896 while ((Outer->getFlags() & Scope::TemplateParamScope) != 0)
1897 Outer = Outer->getParent();
1898 PushOnScopeChains(NewTemplate, Outer);
1900 if (PrevClassTemplate && PrevClassTemplate->getAccess() != AS_none) {
1901 NewTemplate->setAccess(PrevClassTemplate->getAccess());
1902 NewClass->setAccess(PrevClassTemplate->getAccess());
1905 NewTemplate->setObjectOfFriendDecl();
1907 // Friend templates are visible in fairly strange ways.
1908 if (!CurContext->isDependentContext()) {
1909 DeclContext *DC = SemanticContext->getRedeclContext();
1910 DC->makeDeclVisibleInContext(NewTemplate);
1911 if (Scope *EnclosingScope = getScopeForDeclContext(S, DC))
1912 PushOnScopeChains(NewTemplate, EnclosingScope,
1913 /* AddToContext = */ false);
1916 FriendDecl *Friend = FriendDecl::Create(
1917 Context, CurContext, NewClass->getLocation(), NewTemplate, FriendLoc);
1918 Friend->setAccess(AS_public);
1919 CurContext->addDecl(Friend);
1922 if (PrevClassTemplate)
1923 CheckRedeclarationModuleOwnership(NewTemplate, PrevClassTemplate);
1926 NewTemplate->setInvalidDecl();
1927 NewClass->setInvalidDecl();
1930 ActOnDocumentableDecl(NewTemplate);
1932 if (SkipBody && SkipBody->ShouldSkip)
1933 return SkipBody->Previous;
1939 /// Tree transform to "extract" a transformed type from a class template's
1940 /// constructor to a deduction guide.
1941 class ExtractTypeForDeductionGuide
1942 : public TreeTransform<ExtractTypeForDeductionGuide> {
1944 typedef TreeTransform<ExtractTypeForDeductionGuide> Base;
1945 ExtractTypeForDeductionGuide(Sema &SemaRef) : Base(SemaRef) {}
1947 TypeSourceInfo *transform(TypeSourceInfo *TSI) { return TransformType(TSI); }
1949 QualType TransformTypedefType(TypeLocBuilder &TLB, TypedefTypeLoc TL) {
1950 return TransformType(
1952 TL.getTypedefNameDecl()->getTypeSourceInfo()->getTypeLoc());
1956 /// Transform to convert portions of a constructor declaration into the
1957 /// corresponding deduction guide, per C++1z [over.match.class.deduct]p1.
1958 struct ConvertConstructorToDeductionGuideTransform {
1959 ConvertConstructorToDeductionGuideTransform(Sema &S,
1960 ClassTemplateDecl *Template)
1961 : SemaRef(S), Template(Template) {}
1964 ClassTemplateDecl *Template;
1966 DeclContext *DC = Template->getDeclContext();
1967 CXXRecordDecl *Primary = Template->getTemplatedDecl();
1968 DeclarationName DeductionGuideName =
1969 SemaRef.Context.DeclarationNames.getCXXDeductionGuideName(Template);
1971 QualType DeducedType = SemaRef.Context.getTypeDeclType(Primary);
1973 // Index adjustment to apply to convert depth-1 template parameters into
1974 // depth-0 template parameters.
1975 unsigned Depth1IndexAdjustment = Template->getTemplateParameters()->size();
1977 /// Transform a constructor declaration into a deduction guide.
1978 NamedDecl *transformConstructor(FunctionTemplateDecl *FTD,
1979 CXXConstructorDecl *CD) {
1980 SmallVector<TemplateArgument, 16> SubstArgs;
1982 LocalInstantiationScope Scope(SemaRef);
1984 // C++ [over.match.class.deduct]p1:
1985 // -- For each constructor of the class template designated by the
1986 // template-name, a function template with the following properties:
1988 // -- The template parameters are the template parameters of the class
1989 // template followed by the template parameters (including default
1990 // template arguments) of the constructor, if any.
1991 TemplateParameterList *TemplateParams = Template->getTemplateParameters();
1993 TemplateParameterList *InnerParams = FTD->getTemplateParameters();
1994 SmallVector<NamedDecl *, 16> AllParams;
1995 AllParams.reserve(TemplateParams->size() + InnerParams->size());
1996 AllParams.insert(AllParams.begin(),
1997 TemplateParams->begin(), TemplateParams->end());
1998 SubstArgs.reserve(InnerParams->size());
2000 // Later template parameters could refer to earlier ones, so build up
2001 // a list of substituted template arguments as we go.
2002 for (NamedDecl *Param : *InnerParams) {
2003 MultiLevelTemplateArgumentList Args;
2004 Args.addOuterTemplateArguments(SubstArgs);
2005 Args.addOuterRetainedLevel();
2006 NamedDecl *NewParam = transformTemplateParameter(Param, Args);
2009 AllParams.push_back(NewParam);
2010 SubstArgs.push_back(SemaRef.Context.getCanonicalTemplateArgument(
2011 SemaRef.Context.getInjectedTemplateArg(NewParam)));
2013 TemplateParams = TemplateParameterList::Create(
2014 SemaRef.Context, InnerParams->getTemplateLoc(),
2015 InnerParams->getLAngleLoc(), AllParams, InnerParams->getRAngleLoc(),
2016 /*FIXME: RequiresClause*/ nullptr);
2019 // If we built a new template-parameter-list, track that we need to
2020 // substitute references to the old parameters into references to the
2022 MultiLevelTemplateArgumentList Args;
2024 Args.addOuterTemplateArguments(SubstArgs);
2025 Args.addOuterRetainedLevel();
2028 FunctionProtoTypeLoc FPTL = CD->getTypeSourceInfo()->getTypeLoc()
2029 .getAsAdjusted<FunctionProtoTypeLoc>();
2030 assert(FPTL && "no prototype for constructor declaration");
2032 // Transform the type of the function, adjusting the return type and
2033 // replacing references to the old parameters with references to the
2036 SmallVector<ParmVarDecl*, 8> Params;
2037 QualType NewType = transformFunctionProtoType(TLB, FPTL, Params, Args);
2038 if (NewType.isNull())
2040 TypeSourceInfo *NewTInfo = TLB.getTypeSourceInfo(SemaRef.Context, NewType);
2042 return buildDeductionGuide(TemplateParams, CD->getExplicitSpecifier(),
2043 NewTInfo, CD->getBeginLoc(), CD->getLocation(),
2047 /// Build a deduction guide with the specified parameter types.
2048 NamedDecl *buildSimpleDeductionGuide(MutableArrayRef<QualType> ParamTypes) {
2049 SourceLocation Loc = Template->getLocation();
2051 // Build the requested type.
2052 FunctionProtoType::ExtProtoInfo EPI;
2053 EPI.HasTrailingReturn = true;
2054 QualType Result = SemaRef.BuildFunctionType(DeducedType, ParamTypes, Loc,
2055 DeductionGuideName, EPI);
2056 TypeSourceInfo *TSI = SemaRef.Context.getTrivialTypeSourceInfo(Result, Loc);
2058 FunctionProtoTypeLoc FPTL =
2059 TSI->getTypeLoc().castAs<FunctionProtoTypeLoc>();
2061 // Build the parameters, needed during deduction / substitution.
2062 SmallVector<ParmVarDecl*, 4> Params;
2063 for (auto T : ParamTypes) {
2064 ParmVarDecl *NewParam = ParmVarDecl::Create(
2065 SemaRef.Context, DC, Loc, Loc, nullptr, T,
2066 SemaRef.Context.getTrivialTypeSourceInfo(T, Loc), SC_None, nullptr);
2067 NewParam->setScopeInfo(0, Params.size());
2068 FPTL.setParam(Params.size(), NewParam);
2069 Params.push_back(NewParam);
2072 return buildDeductionGuide(Template->getTemplateParameters(),
2073 ExplicitSpecifier(), TSI, Loc, Loc, Loc);
2077 /// Transform a constructor template parameter into a deduction guide template
2078 /// parameter, rebuilding any internal references to earlier parameters and
2079 /// renumbering as we go.
2080 NamedDecl *transformTemplateParameter(NamedDecl *TemplateParam,
2081 MultiLevelTemplateArgumentList &Args) {
2082 if (auto *TTP = dyn_cast<TemplateTypeParmDecl>(TemplateParam)) {
2083 // TemplateTypeParmDecl's index cannot be changed after creation, so
2084 // substitute it directly.
2085 auto *NewTTP = TemplateTypeParmDecl::Create(
2086 SemaRef.Context, DC, TTP->getBeginLoc(), TTP->getLocation(),
2087 /*Depth*/ 0, Depth1IndexAdjustment + TTP->getIndex(),
2088 TTP->getIdentifier(), TTP->wasDeclaredWithTypename(),
2089 TTP->isParameterPack(), TTP->hasTypeConstraint(),
2090 TTP->isExpandedParameterPack() ?
2091 llvm::Optional<unsigned>(TTP->getNumExpansionParameters()) : None);
2092 if (const auto *TC = TTP->getTypeConstraint()) {
2093 TemplateArgumentListInfo TransformedArgs;
2094 const auto *ArgsAsWritten = TC->getTemplateArgsAsWritten();
2095 if (!ArgsAsWritten ||
2096 SemaRef.Subst(ArgsAsWritten->getTemplateArgs(),
2097 ArgsAsWritten->NumTemplateArgs, TransformedArgs,
2099 SemaRef.AttachTypeConstraint(
2100 TC->getNestedNameSpecifierLoc(), TC->getConceptNameInfo(),
2101 TC->getNamedConcept(), ArgsAsWritten ? &TransformedArgs : nullptr,
2103 NewTTP->isParameterPack()
2104 ? cast<CXXFoldExpr>(TC->getImmediatelyDeclaredConstraint())
2106 : SourceLocation());
2108 if (TTP->hasDefaultArgument()) {
2109 TypeSourceInfo *InstantiatedDefaultArg =
2110 SemaRef.SubstType(TTP->getDefaultArgumentInfo(), Args,
2111 TTP->getDefaultArgumentLoc(), TTP->getDeclName());
2112 if (InstantiatedDefaultArg)
2113 NewTTP->setDefaultArgument(InstantiatedDefaultArg);
2115 SemaRef.CurrentInstantiationScope->InstantiatedLocal(TemplateParam,
2120 if (auto *TTP = dyn_cast<TemplateTemplateParmDecl>(TemplateParam))
2121 return transformTemplateParameterImpl(TTP, Args);
2123 return transformTemplateParameterImpl(
2124 cast<NonTypeTemplateParmDecl>(TemplateParam), Args);
2126 template<typename TemplateParmDecl>
2128 transformTemplateParameterImpl(TemplateParmDecl *OldParam,
2129 MultiLevelTemplateArgumentList &Args) {
2130 // Ask the template instantiator to do the heavy lifting for us, then adjust
2131 // the index of the parameter once it's done.
2133 cast<TemplateParmDecl>(SemaRef.SubstDecl(OldParam, DC, Args));
2134 assert(NewParam->getDepth() == 0 && "unexpected template param depth");
2135 NewParam->setPosition(NewParam->getPosition() + Depth1IndexAdjustment);
2139 QualType transformFunctionProtoType(TypeLocBuilder &TLB,
2140 FunctionProtoTypeLoc TL,
2141 SmallVectorImpl<ParmVarDecl*> &Params,
2142 MultiLevelTemplateArgumentList &Args) {
2143 SmallVector<QualType, 4> ParamTypes;
2144 const FunctionProtoType *T = TL.getTypePtr();
2146 // -- The types of the function parameters are those of the constructor.
2147 for (auto *OldParam : TL.getParams()) {
2148 ParmVarDecl *NewParam = transformFunctionTypeParam(OldParam, Args);
2151 ParamTypes.push_back(NewParam->getType());
2152 Params.push_back(NewParam);
2155 // -- The return type is the class template specialization designated by
2156 // the template-name and template arguments corresponding to the
2157 // template parameters obtained from the class template.
2159 // We use the injected-class-name type of the primary template instead.
2160 // This has the convenient property that it is different from any type that
2161 // the user can write in a deduction-guide (because they cannot enter the
2162 // context of the template), so implicit deduction guides can never collide
2163 // with explicit ones.
2164 QualType ReturnType = DeducedType;
2165 TLB.pushTypeSpec(ReturnType).setNameLoc(Primary->getLocation());
2167 // Resolving a wording defect, we also inherit the variadicness of the
2169 FunctionProtoType::ExtProtoInfo EPI;
2170 EPI.Variadic = T->isVariadic();
2171 EPI.HasTrailingReturn = true;
2173 QualType Result = SemaRef.BuildFunctionType(
2174 ReturnType, ParamTypes, TL.getBeginLoc(), DeductionGuideName, EPI);
2175 if (Result.isNull())
2178 FunctionProtoTypeLoc NewTL = TLB.push<FunctionProtoTypeLoc>(Result);
2179 NewTL.setLocalRangeBegin(TL.getLocalRangeBegin());
2180 NewTL.setLParenLoc(TL.getLParenLoc());
2181 NewTL.setRParenLoc(TL.getRParenLoc());
2182 NewTL.setExceptionSpecRange(SourceRange());
2183 NewTL.setLocalRangeEnd(TL.getLocalRangeEnd());
2184 for (unsigned I = 0, E = NewTL.getNumParams(); I != E; ++I)
2185 NewTL.setParam(I, Params[I]);
2191 transformFunctionTypeParam(ParmVarDecl *OldParam,
2192 MultiLevelTemplateArgumentList &Args) {
2193 TypeSourceInfo *OldDI = OldParam->getTypeSourceInfo();
2194 TypeSourceInfo *NewDI;
2195 if (auto PackTL = OldDI->getTypeLoc().getAs<PackExpansionTypeLoc>()) {
2196 // Expand out the one and only element in each inner pack.
2197 Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, 0);
2199 SemaRef.SubstType(PackTL.getPatternLoc(), Args,
2200 OldParam->getLocation(), OldParam->getDeclName());
2201 if (!NewDI) return nullptr;
2203 SemaRef.CheckPackExpansion(NewDI, PackTL.getEllipsisLoc(),
2204 PackTL.getTypePtr()->getNumExpansions());
2206 NewDI = SemaRef.SubstType(OldDI, Args, OldParam->getLocation(),
2207 OldParam->getDeclName());
2211 // Extract the type. This (for instance) replaces references to typedef
2212 // members of the current instantiations with the definitions of those
2213 // typedefs, avoiding triggering instantiation of the deduced type during
2215 NewDI = ExtractTypeForDeductionGuide(SemaRef).transform(NewDI);
2217 // Resolving a wording defect, we also inherit default arguments from the
2219 ExprResult NewDefArg;
2220 if (OldParam->hasDefaultArg()) {
2221 // We don't care what the value is (we won't use it); just create a
2222 // placeholder to indicate there is a default argument.
2223 QualType ParamTy = NewDI->getType();
2224 NewDefArg = new (SemaRef.Context)
2225 OpaqueValueExpr(OldParam->getDefaultArg()->getBeginLoc(),
2226 ParamTy.getNonLValueExprType(SemaRef.Context),
2227 ParamTy->isLValueReferenceType() ? VK_LValue :
2228 ParamTy->isRValueReferenceType() ? VK_XValue :
2232 ParmVarDecl *NewParam = ParmVarDecl::Create(SemaRef.Context, DC,
2233 OldParam->getInnerLocStart(),
2234 OldParam->getLocation(),
2235 OldParam->getIdentifier(),
2238 OldParam->getStorageClass(),
2240 NewParam->setScopeInfo(OldParam->getFunctionScopeDepth(),
2241 OldParam->getFunctionScopeIndex());
2242 SemaRef.CurrentInstantiationScope->InstantiatedLocal(OldParam, NewParam);
2246 NamedDecl *buildDeductionGuide(TemplateParameterList *TemplateParams,
2247 ExplicitSpecifier ES, TypeSourceInfo *TInfo,
2248 SourceLocation LocStart, SourceLocation Loc,
2249 SourceLocation LocEnd) {
2250 DeclarationNameInfo Name(DeductionGuideName, Loc);
2251 ArrayRef<ParmVarDecl *> Params =
2252 TInfo->getTypeLoc().castAs<FunctionProtoTypeLoc>().getParams();
2254 // Build the implicit deduction guide template.
2256 CXXDeductionGuideDecl::Create(SemaRef.Context, DC, LocStart, ES, Name,
2257 TInfo->getType(), TInfo, LocEnd);
2258 Guide->setImplicit();
2259 Guide->setParams(Params);
2261 for (auto *Param : Params)
2262 Param->setDeclContext(Guide);
2264 auto *GuideTemplate = FunctionTemplateDecl::Create(
2265 SemaRef.Context, DC, Loc, DeductionGuideName, TemplateParams, Guide);
2266 GuideTemplate->setImplicit();
2267 Guide->setDescribedFunctionTemplate(GuideTemplate);
2269 if (isa<CXXRecordDecl>(DC)) {
2270 Guide->setAccess(AS_public);
2271 GuideTemplate->setAccess(AS_public);
2274 DC->addDecl(GuideTemplate);
2275 return GuideTemplate;
2280 void Sema::DeclareImplicitDeductionGuides(TemplateDecl *Template,
2281 SourceLocation Loc) {
2282 if (CXXRecordDecl *DefRecord =
2283 cast<CXXRecordDecl>(Template->getTemplatedDecl())->getDefinition()) {
2284 TemplateDecl *DescribedTemplate = DefRecord->getDescribedClassTemplate();
2285 Template = DescribedTemplate ? DescribedTemplate : Template;
2288 DeclContext *DC = Template->getDeclContext();
2289 if (DC->isDependentContext())
2292 ConvertConstructorToDeductionGuideTransform Transform(
2293 *this, cast<ClassTemplateDecl>(Template));
2294 if (!isCompleteType(Loc, Transform.DeducedType))
2297 // Check whether we've already declared deduction guides for this template.
2298 // FIXME: Consider storing a flag on the template to indicate this.
2299 auto Existing = DC->lookup(Transform.DeductionGuideName);
2300 for (auto *D : Existing)
2301 if (D->isImplicit())
2304 // In case we were expanding a pack when we attempted to declare deduction
2305 // guides, turn off pack expansion for everything we're about to do.
2306 ArgumentPackSubstitutionIndexRAII SubstIndex(*this, -1);
2307 // Create a template instantiation record to track the "instantiation" of
2308 // constructors into deduction guides.
2309 // FIXME: Add a kind for this to give more meaningful diagnostics. But can
2310 // this substitution process actually fail?
2311 InstantiatingTemplate BuildingDeductionGuides(*this, Loc, Template);
2312 if (BuildingDeductionGuides.isInvalid())
2315 // Convert declared constructors into deduction guide templates.
2316 // FIXME: Skip constructors for which deduction must necessarily fail (those
2317 // for which some class template parameter without a default argument never
2318 // appears in a deduced context).
2319 bool AddedAny = false;
2320 for (NamedDecl *D : LookupConstructors(Transform.Primary)) {
2321 D = D->getUnderlyingDecl();
2322 if (D->isInvalidDecl() || D->isImplicit())
2324 D = cast<NamedDecl>(D->getCanonicalDecl());
2326 auto *FTD = dyn_cast<FunctionTemplateDecl>(D);
2328 dyn_cast_or_null<CXXConstructorDecl>(FTD ? FTD->getTemplatedDecl() : D);
2329 // Class-scope explicit specializations (MS extension) do not result in
2330 // deduction guides.
2331 if (!CD || (!FTD && CD->isFunctionTemplateSpecialization()))
2334 Transform.transformConstructor(FTD, CD);
2338 // C++17 [over.match.class.deduct]
2339 // -- If C is not defined or does not declare any constructors, an
2340 // additional function template derived as above from a hypothetical
2343 Transform.buildSimpleDeductionGuide(None);
2345 // -- An additional function template derived as above from a hypothetical
2346 // constructor C(C), called the copy deduction candidate.
2347 cast<CXXDeductionGuideDecl>(
2348 cast<FunctionTemplateDecl>(
2349 Transform.buildSimpleDeductionGuide(Transform.DeducedType))
2350 ->getTemplatedDecl())
2351 ->setIsCopyDeductionCandidate();
2354 /// Diagnose the presence of a default template argument on a
2355 /// template parameter, which is ill-formed in certain contexts.
2357 /// \returns true if the default template argument should be dropped.
2358 static bool DiagnoseDefaultTemplateArgument(Sema &S,
2359 Sema::TemplateParamListContext TPC,
2360 SourceLocation ParamLoc,
2361 SourceRange DefArgRange) {
2363 case Sema::TPC_ClassTemplate:
2364 case Sema::TPC_VarTemplate:
2365 case Sema::TPC_TypeAliasTemplate:
2368 case Sema::TPC_FunctionTemplate:
2369 case Sema::TPC_FriendFunctionTemplateDefinition:
2370 // C++ [temp.param]p9:
2371 // A default template-argument shall not be specified in a
2372 // function template declaration or a function template
2374 // If a friend function template declaration specifies a default
2375 // template-argument, that declaration shall be a definition and shall be
2376 // the only declaration of the function template in the translation unit.
2377 // (C++98/03 doesn't have this wording; see DR226).
2378 S.Diag(ParamLoc, S.getLangOpts().CPlusPlus11 ?
2379 diag::warn_cxx98_compat_template_parameter_default_in_function_template
2380 : diag::ext_template_parameter_default_in_function_template)
2384 case Sema::TPC_ClassTemplateMember:
2385 // C++0x [temp.param]p9:
2386 // A default template-argument shall not be specified in the
2387 // template-parameter-lists of the definition of a member of a
2388 // class template that appears outside of the member's class.
2389 S.Diag(ParamLoc, diag::err_template_parameter_default_template_member)
2393 case Sema::TPC_FriendClassTemplate:
2394 case Sema::TPC_FriendFunctionTemplate:
2395 // C++ [temp.param]p9:
2396 // A default template-argument shall not be specified in a
2397 // friend template declaration.
2398 S.Diag(ParamLoc, diag::err_template_parameter_default_friend_template)
2402 // FIXME: C++0x [temp.param]p9 allows default template-arguments
2403 // for friend function templates if there is only a single
2404 // declaration (and it is a definition). Strange!
2407 llvm_unreachable("Invalid TemplateParamListContext!");
2410 /// Check for unexpanded parameter packs within the template parameters
2411 /// of a template template parameter, recursively.
2412 static bool DiagnoseUnexpandedParameterPacks(Sema &S,
2413 TemplateTemplateParmDecl *TTP) {
2414 // A template template parameter which is a parameter pack is also a pack
2416 if (TTP->isParameterPack())
2419 TemplateParameterList *Params = TTP->getTemplateParameters();
2420 for (unsigned I = 0, N = Params->size(); I != N; ++I) {
2421 NamedDecl *P = Params->getParam(I);
2422 if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(P)) {
2423 if (!TTP->isParameterPack())
2424 if (const TypeConstraint *TC = TTP->getTypeConstraint())
2425 if (TC->hasExplicitTemplateArgs())
2426 for (auto &ArgLoc : TC->getTemplateArgsAsWritten()->arguments())
2427 if (S.DiagnoseUnexpandedParameterPack(ArgLoc,
2428 Sema::UPPC_TypeConstraint))
2433 if (NonTypeTemplateParmDecl *NTTP = dyn_cast<NonTypeTemplateParmDecl>(P)) {
2434 if (!NTTP->isParameterPack() &&
2435 S.DiagnoseUnexpandedParameterPack(NTTP->getLocation(),
2436 NTTP->getTypeSourceInfo(),
2437 Sema::UPPC_NonTypeTemplateParameterType))
2443 if (TemplateTemplateParmDecl *InnerTTP
2444 = dyn_cast<TemplateTemplateParmDecl>(P))
2445 if (DiagnoseUnexpandedParameterPacks(S, InnerTTP))
2452 /// Checks the validity of a template parameter list, possibly
2453 /// considering the template parameter list from a previous
2456 /// If an "old" template parameter list is provided, it must be
2457 /// equivalent (per TemplateParameterListsAreEqual) to the "new"
2458 /// template parameter list.
2460 /// \param NewParams Template parameter list for a new template
2461 /// declaration. This template parameter list will be updated with any
2462 /// default arguments that are carried through from the previous
2463 /// template parameter list.
2465 /// \param OldParams If provided, template parameter list from a
2466 /// previous declaration of the same template. Default template
2467 /// arguments will be merged from the old template parameter list to
2468 /// the new template parameter list.
2470 /// \param TPC Describes the context in which we are checking the given
2471 /// template parameter list.
2473 /// \param SkipBody If we might have already made a prior merged definition
2474 /// of this template visible, the corresponding body-skipping information.
2475 /// Default argument redefinition is not an error when skipping such a body,
2476 /// because (under the ODR) we can assume the default arguments are the same
2477 /// as the prior merged definition.
2479 /// \returns true if an error occurred, false otherwise.
2480 bool Sema::CheckTemplateParameterList(TemplateParameterList *NewParams,
2481 TemplateParameterList *OldParams,
2482 TemplateParamListContext TPC,
2483 SkipBodyInfo *SkipBody) {
2484 bool Invalid = false;
2486 // C++ [temp.param]p10:
2487 // The set of default template-arguments available for use with a
2488 // template declaration or definition is obtained by merging the
2489 // default arguments from the definition (if in scope) and all
2490 // declarations in scope in the same way default function
2491 // arguments are (8.3.6).
2492 bool SawDefaultArgument = false;
2493 SourceLocation PreviousDefaultArgLoc;
2495 // Dummy initialization to avoid warnings.
2496 TemplateParameterList::iterator OldParam = NewParams->end();
2498 OldParam = OldParams->begin();
2500 bool RemoveDefaultArguments = false;
2501 for (TemplateParameterList::iterator NewParam = NewParams->begin(),
2502 NewParamEnd = NewParams->end();
2503 NewParam != NewParamEnd; ++NewParam) {
2504 // Variables used to diagnose redundant default arguments
2505 bool RedundantDefaultArg = false;
2506 SourceLocation OldDefaultLoc;
2507 SourceLocation NewDefaultLoc;
2509 // Variable used to diagnose missing default arguments
2510 bool MissingDefaultArg = false;
2512 // Variable used to diagnose non-final parameter packs
2513 bool SawParameterPack = false;
2515 if (TemplateTypeParmDecl *NewTypeParm
2516 = dyn_cast<TemplateTypeParmDecl>(*NewParam)) {
2517 // Check the presence of a default argument here.
2518 if (NewTypeParm->hasDefaultArgument() &&
2519 DiagnoseDefaultTemplateArgument(*this, TPC,
2520 NewTypeParm->getLocation(),
2521 NewTypeParm->getDefaultArgumentInfo()->getTypeLoc()
2523 NewTypeParm->removeDefaultArgument();
2525 // Merge default arguments for template type parameters.
2526 TemplateTypeParmDecl *OldTypeParm
2527 = OldParams? cast<TemplateTypeParmDecl>(*OldParam) : nullptr;
2528 if (NewTypeParm->isParameterPack()) {
2529 assert(!NewTypeParm->hasDefaultArgument() &&
2530 "Parameter packs can't have a default argument!");
2531 SawParameterPack = true;
2532 } else if (OldTypeParm && hasVisibleDefaultArgument(OldTypeParm) &&
2533 NewTypeParm->hasDefaultArgument() &&
2534 (!SkipBody || !SkipBody->ShouldSkip)) {
2535 OldDefaultLoc = OldTypeParm->getDefaultArgumentLoc();
2536 NewDefaultLoc = NewTypeParm->getDefaultArgumentLoc();
2537 SawDefaultArgument = true;
2538 RedundantDefaultArg = true;
2539 PreviousDefaultArgLoc = NewDefaultLoc;
2540 } else if (OldTypeParm && OldTypeParm->hasDefaultArgument()) {
2541 // Merge the default argument from the old declaration to the
2543 NewTypeParm->setInheritedDefaultArgument(Context, OldTypeParm);
2544 PreviousDefaultArgLoc = OldTypeParm->getDefaultArgumentLoc();
2545 } else if (NewTypeParm->hasDefaultArgument()) {
2546 SawDefaultArgument = true;
2547 PreviousDefaultArgLoc = NewTypeParm->getDefaultArgumentLoc();
2548 } else if (SawDefaultArgument)
2549 MissingDefaultArg = true;
2550 } else if (NonTypeTemplateParmDecl *NewNonTypeParm
2551 = dyn_cast<NonTypeTemplateParmDecl>(*NewParam)) {
2552 // Check for unexpanded parameter packs.
2553 if (!NewNonTypeParm->isParameterPack() &&
2554 DiagnoseUnexpandedParameterPack(NewNonTypeParm->getLocation(),
2555 NewNonTypeParm->getTypeSourceInfo(),
2556 UPPC_NonTypeTemplateParameterType)) {
2561 // Check the presence of a default argument here.
2562 if (NewNonTypeParm->hasDefaultArgument() &&
2563 DiagnoseDefaultTemplateArgument(*this, TPC,
2564 NewNonTypeParm->getLocation(),
2565 NewNonTypeParm->getDefaultArgument()->getSourceRange())) {
2566 NewNonTypeParm->removeDefaultArgument();
2569 // Merge default arguments for non-type template parameters
2570 NonTypeTemplateParmDecl *OldNonTypeParm
2571 = OldParams? cast<NonTypeTemplateParmDecl>(*OldParam) : nullptr;
2572 if (NewNonTypeParm->isParameterPack()) {
2573 assert(!NewNonTypeParm->hasDefaultArgument() &&
2574 "Parameter packs can't have a default argument!");
2575 if (!NewNonTypeParm->isPackExpansion())
2576 SawParameterPack = true;
2577 } else if (OldNonTypeParm && hasVisibleDefaultArgument(OldNonTypeParm) &&
2578 NewNonTypeParm->hasDefaultArgument() &&
2579 (!SkipBody || !SkipBody->ShouldSkip)) {
2580 OldDefaultLoc = OldNonTypeParm->getDefaultArgumentLoc();
2581 NewDefaultLoc = NewNonTypeParm->getDefaultArgumentLoc();
2582 SawDefaultArgument = true;
2583 RedundantDefaultArg = true;
2584 PreviousDefaultArgLoc = NewDefaultLoc;
2585 } else if (OldNonTypeParm && OldNonTypeParm->hasDefaultArgument()) {
2586 // Merge the default argument from the old declaration to the
2588 NewNonTypeParm->setInheritedDefaultArgument(Context, OldNonTypeParm);
2589 PreviousDefaultArgLoc = OldNonTypeParm->getDefaultArgumentLoc();
2590 } else if (NewNonTypeParm->hasDefaultArgument()) {
2591 SawDefaultArgument = true;
2592 PreviousDefaultArgLoc = NewNonTypeParm->getDefaultArgumentLoc();
2593 } else if (SawDefaultArgument)
2594 MissingDefaultArg = true;
2596 TemplateTemplateParmDecl *NewTemplateParm
2597 = cast<TemplateTemplateParmDecl>(*NewParam);
2599 // Check for unexpanded parameter packs, recursively.
2600 if (::DiagnoseUnexpandedParameterPacks(*this, NewTemplateParm)) {
2605 // Check the presence of a default argument here.
2606 if (NewTemplateParm->hasDefaultArgument() &&
2607 DiagnoseDefaultTemplateArgument(*this, TPC,
2608 NewTemplateParm->getLocation(),
2609 NewTemplateParm->getDefaultArgument().getSourceRange()))
2610 NewTemplateParm->removeDefaultArgument();
2612 // Merge default arguments for template template parameters
2613 TemplateTemplateParmDecl *OldTemplateParm
2614 = OldParams? cast<TemplateTemplateParmDecl>(*OldParam) : nullptr;
2615 if (NewTemplateParm->isParameterPack()) {
2616 assert(!NewTemplateParm->hasDefaultArgument() &&
2617 "Parameter packs can't have a default argument!");
2618 if (!NewTemplateParm->isPackExpansion())
2619 SawParameterPack = true;
2620 } else if (OldTemplateParm &&
2621 hasVisibleDefaultArgument(OldTemplateParm) &&
2622 NewTemplateParm->hasDefaultArgument() &&
2623 (!SkipBody || !SkipBody->ShouldSkip)) {
2624 OldDefaultLoc = OldTemplateParm->getDefaultArgument().getLocation();
2625 NewDefaultLoc = NewTemplateParm->getDefaultArgument().getLocation();
2626 SawDefaultArgument = true;
2627 RedundantDefaultArg = true;
2628 PreviousDefaultArgLoc = NewDefaultLoc;
2629 } else if (OldTemplateParm && OldTemplateParm->hasDefaultArgument()) {
2630 // Merge the default argument from the old declaration to the
2632 NewTemplateParm->setInheritedDefaultArgument(Context, OldTemplateParm);
2633 PreviousDefaultArgLoc
2634 = OldTemplateParm->getDefaultArgument().getLocation();
2635 } else if (NewTemplateParm->hasDefaultArgument()) {
2636 SawDefaultArgument = true;
2637 PreviousDefaultArgLoc
2638 = NewTemplateParm->getDefaultArgument().getLocation();
2639 } else if (SawDefaultArgument)
2640 MissingDefaultArg = true;
2643 // C++11 [temp.param]p11:
2644 // If a template parameter of a primary class template or alias template
2645 // is a template parameter pack, it shall be the last template parameter.
2646 if (SawParameterPack && (NewParam + 1) != NewParamEnd &&
2647 (TPC == TPC_ClassTemplate || TPC == TPC_VarTemplate ||
2648 TPC == TPC_TypeAliasTemplate)) {
2649 Diag((*NewParam)->getLocation(),
2650 diag::err_template_param_pack_must_be_last_template_parameter);
2654 if (RedundantDefaultArg) {
2655 // C++ [temp.param]p12:
2656 // A template-parameter shall not be given default arguments
2657 // by two different declarations in the same scope.
2658 Diag(NewDefaultLoc, diag::err_template_param_default_arg_redefinition);
2659 Diag(OldDefaultLoc, diag::note_template_param_prev_default_arg);
2661 } else if (MissingDefaultArg && TPC != TPC_FunctionTemplate) {
2662 // C++ [temp.param]p11:
2663 // If a template-parameter of a class template has a default
2664 // template-argument, each subsequent template-parameter shall either
2665 // have a default template-argument supplied or be a template parameter
2667 Diag((*NewParam)->getLocation(),
2668 diag::err_template_param_default_arg_missing);
2669 Diag(PreviousDefaultArgLoc, diag::note_template_param_prev_default_arg);
2671 RemoveDefaultArguments = true;
2674 // If we have an old template parameter list that we're merging
2675 // in, move on to the next parameter.
2680 // We were missing some default arguments at the end of the list, so remove
2681 // all of the default arguments.
2682 if (RemoveDefaultArguments) {
2683 for (TemplateParameterList::iterator NewParam = NewParams->begin(),
2684 NewParamEnd = NewParams->end();
2685 NewParam != NewParamEnd; ++NewParam) {
2686 if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(*NewParam))
2687 TTP->removeDefaultArgument();
2688 else if (NonTypeTemplateParmDecl *NTTP
2689 = dyn_cast<NonTypeTemplateParmDecl>(*NewParam))
2690 NTTP->removeDefaultArgument();
2692 cast<TemplateTemplateParmDecl>(*NewParam)->removeDefaultArgument();
2701 /// A class which looks for a use of a certain level of template
2703 struct DependencyChecker : RecursiveASTVisitor<DependencyChecker> {
2704 typedef RecursiveASTVisitor<DependencyChecker> super;
2708 // Whether we're looking for a use of a template parameter that makes the
2709 // overall construct type-dependent / a dependent type. This is strictly
2710 // best-effort for now; we may fail to match at all for a dependent type
2711 // in some cases if this is set.
2712 bool IgnoreNonTypeDependent;
2715 SourceLocation MatchLoc;
2717 DependencyChecker(unsigned Depth, bool IgnoreNonTypeDependent)
2718 : Depth(Depth), IgnoreNonTypeDependent(IgnoreNonTypeDependent),
2721 DependencyChecker(TemplateParameterList *Params, bool IgnoreNonTypeDependent)
2722 : IgnoreNonTypeDependent(IgnoreNonTypeDependent), Match(false) {
2723 NamedDecl *ND = Params->getParam(0);
2724 if (TemplateTypeParmDecl *PD = dyn_cast<TemplateTypeParmDecl>(ND)) {
2725 Depth = PD->getDepth();
2726 } else if (NonTypeTemplateParmDecl *PD =
2727 dyn_cast<NonTypeTemplateParmDecl>(ND)) {
2728 Depth = PD->getDepth();
2730 Depth = cast<TemplateTemplateParmDecl>(ND)->getDepth();
2734 bool Matches(unsigned ParmDepth, SourceLocation Loc = SourceLocation()) {
2735 if (ParmDepth >= Depth) {
2743 bool TraverseStmt(Stmt *S, DataRecursionQueue *Q = nullptr) {
2744 // Prune out non-type-dependent expressions if requested. This can
2745 // sometimes result in us failing to find a template parameter reference
2746 // (if a value-dependent expression creates a dependent type), but this
2747 // mode is best-effort only.
2748 if (auto *E = dyn_cast_or_null<Expr>(S))
2749 if (IgnoreNonTypeDependent && !E->isTypeDependent())
2751 return super::TraverseStmt(S, Q);
2754 bool TraverseTypeLoc(TypeLoc TL) {
2755 if (IgnoreNonTypeDependent && !TL.isNull() &&
2756 !TL.getType()->isDependentType())
2758 return super::TraverseTypeLoc(TL);
2761 bool VisitTemplateTypeParmTypeLoc(TemplateTypeParmTypeLoc TL) {
2762 return !Matches(TL.getTypePtr()->getDepth(), TL.getNameLoc());
2765 bool VisitTemplateTypeParmType(const TemplateTypeParmType *T) {
2766 // For a best-effort search, keep looking until we find a location.
2767 return IgnoreNonTypeDependent || !Matches(T->getDepth());
2770 bool TraverseTemplateName(TemplateName N) {
2771 if (TemplateTemplateParmDecl *PD =
2772 dyn_cast_or_null<TemplateTemplateParmDecl>(N.getAsTemplateDecl()))
2773 if (Matches(PD->getDepth()))
2775 return super::TraverseTemplateName(N);
2778 bool VisitDeclRefExpr(DeclRefExpr *E) {
2779 if (NonTypeTemplateParmDecl *PD =
2780 dyn_cast<NonTypeTemplateParmDecl>(E->getDecl()))
2781 if (Matches(PD->getDepth(), E->getExprLoc()))
2783 return super::VisitDeclRefExpr(E);
2786 bool VisitSubstTemplateTypeParmType(const SubstTemplateTypeParmType *T) {
2787 return TraverseType(T->getReplacementType());
2791 VisitSubstTemplateTypeParmPackType(const SubstTemplateTypeParmPackType *T) {
2792 return TraverseTemplateArgument(T->getArgumentPack());
2795 bool TraverseInjectedClassNameType(const InjectedClassNameType *T) {
2796 return TraverseType(T->getInjectedSpecializationType());
2799 } // end anonymous namespace
2801 /// Determines whether a given type depends on the given parameter
2804 DependsOnTemplateParameters(QualType T, TemplateParameterList *Params) {
2805 if (!Params->size())
2808 DependencyChecker Checker(Params, /*IgnoreNonTypeDependent*/false);
2809 Checker.TraverseType(T);
2810 return Checker.Match;
2813 // Find the source range corresponding to the named type in the given
2814 // nested-name-specifier, if any.
2815 static SourceRange getRangeOfTypeInNestedNameSpecifier(ASTContext &Context,
2817 const CXXScopeSpec &SS) {
2818 NestedNameSpecifierLoc NNSLoc(SS.getScopeRep(), SS.location_data());
2819 while (NestedNameSpecifier *NNS = NNSLoc.getNestedNameSpecifier()) {
2820 if (const Type *CurType = NNS->getAsType()) {
2821 if (Context.hasSameUnqualifiedType(T, QualType(CurType, 0)))
2822 return NNSLoc.getTypeLoc().getSourceRange();
2826 NNSLoc = NNSLoc.getPrefix();
2829 return SourceRange();
2832 /// Match the given template parameter lists to the given scope
2833 /// specifier, returning the template parameter list that applies to the
2836 /// \param DeclStartLoc the start of the declaration that has a scope
2837 /// specifier or a template parameter list.
2839 /// \param DeclLoc The location of the declaration itself.
2841 /// \param SS the scope specifier that will be matched to the given template
2842 /// parameter lists. This scope specifier precedes a qualified name that is
2845 /// \param TemplateId The template-id following the scope specifier, if there
2846 /// is one. Used to check for a missing 'template<>'.
2848 /// \param ParamLists the template parameter lists, from the outermost to the
2849 /// innermost template parameter lists.
2851 /// \param IsFriend Whether to apply the slightly different rules for
2852 /// matching template parameters to scope specifiers in friend
2855 /// \param IsMemberSpecialization will be set true if the scope specifier
2856 /// denotes a fully-specialized type, and therefore this is a declaration of
2857 /// a member specialization.
2859 /// \returns the template parameter list, if any, that corresponds to the
2860 /// name that is preceded by the scope specifier @p SS. This template
2861 /// parameter list may have template parameters (if we're declaring a
2862 /// template) or may have no template parameters (if we're declaring a
2863 /// template specialization), or may be NULL (if what we're declaring isn't
2864 /// itself a template).
2865 TemplateParameterList *Sema::MatchTemplateParametersToScopeSpecifier(
2866 SourceLocation DeclStartLoc, SourceLocation DeclLoc, const CXXScopeSpec &SS,
2867 TemplateIdAnnotation *TemplateId,
2868 ArrayRef<TemplateParameterList *> ParamLists, bool IsFriend,
2869 bool &IsMemberSpecialization, bool &Invalid, bool SuppressDiagnostic) {
2870 IsMemberSpecialization = false;
2873 // The sequence of nested types to which we will match up the template
2874 // parameter lists. We first build this list by starting with the type named
2875 // by the nested-name-specifier and walking out until we run out of types.
2876 SmallVector<QualType, 4> NestedTypes;
2878 if (SS.getScopeRep()) {
2879 if (CXXRecordDecl *Record
2880 = dyn_cast_or_null<CXXRecordDecl>(computeDeclContext(SS, true)))
2881 T = Context.getTypeDeclType(Record);
2883 T = QualType(SS.getScopeRep()->getAsType(), 0);
2886 // If we found an explicit specialization that prevents us from needing
2887 // 'template<>' headers, this will be set to the location of that
2888 // explicit specialization.
2889 SourceLocation ExplicitSpecLoc;
2891 while (!T.isNull()) {
2892 NestedTypes.push_back(T);
2894 // Retrieve the parent of a record type.
2895 if (CXXRecordDecl *Record = T->getAsCXXRecordDecl()) {
2896 // If this type is an explicit specialization, we're done.
2897 if (ClassTemplateSpecializationDecl *Spec
2898 = dyn_cast<ClassTemplateSpecializationDecl>(Record)) {
2899 if (!isa<ClassTemplatePartialSpecializationDecl>(Spec) &&
2900 Spec->getSpecializationKind() == TSK_ExplicitSpecialization) {
2901 ExplicitSpecLoc = Spec->getLocation();
2904 } else if (Record->getTemplateSpecializationKind()
2905 == TSK_ExplicitSpecialization) {
2906 ExplicitSpecLoc = Record->getLocation();
2910 if (TypeDecl *Parent = dyn_cast<TypeDecl>(Record->getParent()))
2911 T = Context.getTypeDeclType(Parent);
2917 if (const TemplateSpecializationType *TST
2918 = T->getAs<TemplateSpecializationType>()) {
2919 if (TemplateDecl *Template = TST->getTemplateName().getAsTemplateDecl()) {
2920 if (TypeDecl *Parent = dyn_cast<TypeDecl>(Template->getDeclContext()))
2921 T = Context.getTypeDeclType(Parent);
2928 // Look one step prior in a dependent template specialization type.
2929 if (const DependentTemplateSpecializationType *DependentTST
2930 = T->getAs<DependentTemplateSpecializationType>()) {
2931 if (NestedNameSpecifier *NNS = DependentTST->getQualifier())
2932 T = QualType(NNS->getAsType(), 0);
2938 // Look one step prior in a dependent name type.
2939 if (const DependentNameType *DependentName = T->getAs<DependentNameType>()){
2940 if (NestedNameSpecifier *NNS = DependentName->getQualifier())
2941 T = QualType(NNS->getAsType(), 0);
2947 // Retrieve the parent of an enumeration type.
2948 if (const EnumType *EnumT = T->getAs<EnumType>()) {
2949 // FIXME: Forward-declared enums require a TSK_ExplicitSpecialization
2951 EnumDecl *Enum = EnumT->getDecl();
2953 // Get to the parent type.
2954 if (TypeDecl *Parent = dyn_cast<TypeDecl>(Enum->getParent()))
2955 T = Context.getTypeDeclType(Parent);
2963 // Reverse the nested types list, since we want to traverse from the outermost
2964 // to the innermost while checking template-parameter-lists.
2965 std::reverse(NestedTypes.begin(), NestedTypes.end());
2967 // C++0x [temp.expl.spec]p17:
2968 // A member or a member template may be nested within many
2969 // enclosing class templates. In an explicit specialization for
2970 // such a member, the member declaration shall be preceded by a
2971 // template<> for each enclosing class template that is
2972 // explicitly specialized.
2973 bool SawNonEmptyTemplateParameterList = false;
2975 auto CheckExplicitSpecialization = [&](SourceRange Range, bool Recovery) {
2976 if (SawNonEmptyTemplateParameterList) {
2977 if (!SuppressDiagnostic)
2978 Diag(DeclLoc, diag::err_specialize_member_of_template)
2979 << !Recovery << Range;
2981 IsMemberSpecialization = false;
2988 auto DiagnoseMissingExplicitSpecialization = [&] (SourceRange Range) {
2989 // Check that we can have an explicit specialization here.
2990 if (CheckExplicitSpecialization(Range, true))
2993 // We don't have a template header, but we should.
2994 SourceLocation ExpectedTemplateLoc;
2995 if (!ParamLists.empty())
2996 ExpectedTemplateLoc = ParamLists[0]->getTemplateLoc();
2998 ExpectedTemplateLoc = DeclStartLoc;
3000 if (!SuppressDiagnostic)
3001 Diag(DeclLoc, diag::err_template_spec_needs_header)
3003 << FixItHint::CreateInsertion(ExpectedTemplateLoc, "template<> ");
3007 unsigned ParamIdx = 0;
3008 for (unsigned TypeIdx = 0, NumTypes = NestedTypes.size(); TypeIdx != NumTypes;
3010 T = NestedTypes[TypeIdx];
3012 // Whether we expect a 'template<>' header.
3013 bool NeedEmptyTemplateHeader = false;
3015 // Whether we expect a template header with parameters.
3016 bool NeedNonemptyTemplateHeader = false;
3018 // For a dependent type, the set of template parameters that we
3020 TemplateParameterList *ExpectedTemplateParams = nullptr;
3022 // C++0x [temp.expl.spec]p15:
3023 // A member or a member template may be nested within many enclosing
3024 // class templates. In an explicit specialization for such a member, the
3025 // member declaration shall be preceded by a template<> for each
3026 // enclosing class template that is explicitly specialized.
3027 if (CXXRecordDecl *Record = T->getAsCXXRecordDecl()) {
3028 if (ClassTemplatePartialSpecializationDecl *Partial
3029 = dyn_cast<ClassTemplatePartialSpecializationDecl>(Record)) {
3030 ExpectedTemplateParams = Partial->getTemplateParameters();
3031 NeedNonemptyTemplateHeader = true;
3032 } else if (Record->isDependentType()) {
3033 if (Record->getDescribedClassTemplate()) {
3034 ExpectedTemplateParams = Record->getDescribedClassTemplate()
3035 ->getTemplateParameters();
3036 NeedNonemptyTemplateHeader = true;
3038 } else if (ClassTemplateSpecializationDecl *Spec
3039 = dyn_cast<ClassTemplateSpecializationDecl>(Record)) {
3040 // C++0x [temp.expl.spec]p4:
3041 // Members of an explicitly specialized class template are defined
3042 // in the same manner as members of normal classes, and not using
3043 // the template<> syntax.
3044 if (Spec->getSpecializationKind() != TSK_ExplicitSpecialization)
3045 NeedEmptyTemplateHeader = true;
3048 } else if (Record->getTemplateSpecializationKind()) {
3049 if (Record->getTemplateSpecializationKind()
3050 != TSK_ExplicitSpecialization &&
3051 TypeIdx == NumTypes - 1)
3052 IsMemberSpecialization = true;
3056 } else if (const TemplateSpecializationType *TST
3057 = T->getAs<TemplateSpecializationType>()) {
3058 if (TemplateDecl *Template = TST->getTemplateName().getAsTemplateDecl()) {
3059 ExpectedTemplateParams = Template->getTemplateParameters();
3060 NeedNonemptyTemplateHeader = true;
3062 } else if (T->getAs<DependentTemplateSpecializationType>()) {
3063 // FIXME: We actually could/should check the template arguments here
3064 // against the corresponding template parameter list.
3065 NeedNonemptyTemplateHeader = false;
3068 // C++ [temp.expl.spec]p16:
3069 // In an explicit specialization declaration for a member of a class
3070 // template or a member template that ap- pears in namespace scope, the
3071 // member template and some of its enclosing class templates may remain
3072 // unspecialized, except that the declaration shall not explicitly
3073 // specialize a class member template if its en- closing class templates
3074 // are not explicitly specialized as well.
3075 if (ParamIdx < ParamLists.size()) {
3076 if (ParamLists[ParamIdx]->size() == 0) {
3077 if (CheckExplicitSpecialization(ParamLists[ParamIdx]->getSourceRange(),
3081 SawNonEmptyTemplateParameterList = true;
3084 if (NeedEmptyTemplateHeader) {
3085 // If we're on the last of the types, and we need a 'template<>' header
3086 // here, then it's a member specialization.
3087 if (TypeIdx == NumTypes - 1)
3088 IsMemberSpecialization = true;
3090 if (ParamIdx < ParamLists.size()) {
3091 if (ParamLists[ParamIdx]->size() > 0) {
3092 // The header has template parameters when it shouldn't. Complain.
3093 if (!SuppressDiagnostic)
3094 Diag(ParamLists[ParamIdx]->getTemplateLoc(),
3095 diag::err_template_param_list_matches_nontemplate)
3097 << SourceRange(ParamLists[ParamIdx]->getLAngleLoc(),
3098 ParamLists[ParamIdx]->getRAngleLoc())
3099 << getRangeOfTypeInNestedNameSpecifier(Context, T, SS);
3104 // Consume this template header.
3110 if (DiagnoseMissingExplicitSpecialization(
3111 getRangeOfTypeInNestedNameSpecifier(Context, T, SS)))
3117 if (NeedNonemptyTemplateHeader) {
3118 // In friend declarations we can have template-ids which don't
3119 // depend on the corresponding template parameter lists. But
3120 // assume that empty parameter lists are supposed to match this
3122 if (IsFriend && T->isDependentType()) {
3123 if (ParamIdx < ParamLists.size() &&
3124 DependsOnTemplateParameters(T, ParamLists[ParamIdx]))
3125 ExpectedTemplateParams = nullptr;
3130 if (ParamIdx < ParamLists.size()) {
3131 // Check the template parameter list, if we can.
3132 if (ExpectedTemplateParams &&
3133 !TemplateParameterListsAreEqual(ParamLists[ParamIdx],
3134 ExpectedTemplateParams,
3135 !SuppressDiagnostic, TPL_TemplateMatch))
3139 CheckTemplateParameterList(ParamLists[ParamIdx], nullptr,
3140 TPC_ClassTemplateMember))
3147 if (!SuppressDiagnostic)
3148 Diag(DeclLoc, diag::err_template_spec_needs_template_parameters)
3150 << getRangeOfTypeInNestedNameSpecifier(Context, T, SS);
3156 // If there were at least as many template-ids as there were template
3157 // parameter lists, then there are no template parameter lists remaining for
3158 // the declaration itself.
3159 if (ParamIdx >= ParamLists.size()) {
3160 if (TemplateId && !IsFriend) {
3161 // We don't have a template header for the declaration itself, but we
3163 DiagnoseMissingExplicitSpecialization(SourceRange(TemplateId->LAngleLoc,
3164 TemplateId->RAngleLoc));
3166 // Fabricate an empty template parameter list for the invented header.
3167 return TemplateParameterList::Create(Context, SourceLocation(),
3168 SourceLocation(), None,
3169 SourceLocation(), nullptr);
3175 // If there were too many template parameter lists, complain about that now.
3176 if (ParamIdx < ParamLists.size() - 1) {
3177 bool HasAnyExplicitSpecHeader = false;
3178 bool AllExplicitSpecHeaders = true;
3179 for (unsigned I = ParamIdx, E = ParamLists.size() - 1; I != E; ++I) {
3180 if (ParamLists[I]->size() == 0)
3181 HasAnyExplicitSpecHeader = true;
3183 AllExplicitSpecHeaders = false;
3186 if (!SuppressDiagnostic)
3187 Diag(ParamLists[ParamIdx]->getTemplateLoc(),
3188 AllExplicitSpecHeaders ? diag::warn_template_spec_extra_headers
3189 : diag::err_template_spec_extra_headers)
3190 << SourceRange(ParamLists[ParamIdx]->getTemplateLoc(),
3191 ParamLists[ParamLists.size() - 2]->getRAngleLoc());
3193 // If there was a specialization somewhere, such that 'template<>' is
3194 // not required, and there were any 'template<>' headers, note where the
3195 // specialization occurred.
3196 if (ExplicitSpecLoc.isValid() && HasAnyExplicitSpecHeader &&
3197 !SuppressDiagnostic)
3198 Diag(ExplicitSpecLoc,
3199 diag::note_explicit_template_spec_does_not_need_header)
3200 << NestedTypes.back();
3202 // We have a template parameter list with no corresponding scope, which
3203 // means that the resulting template declaration can't be instantiated
3204 // properly (we'll end up with dependent nodes when we shouldn't).
3205 if (!AllExplicitSpecHeaders)
3209 // C++ [temp.expl.spec]p16:
3210 // In an explicit specialization declaration for a member of a class
3211 // template or a member template that ap- pears in namespace scope, the
3212 // member template and some of its enclosing class templates may remain
3213 // unspecialized, except that the declaration shall not explicitly
3214 // specialize a class member template if its en- closing class templates
3215 // are not explicitly specialized as well.
3216 if (ParamLists.back()->size() == 0 &&
3217 CheckExplicitSpecialization(ParamLists[ParamIdx]->getSourceRange(),
3221 // Return the last template parameter list, which corresponds to the
3222 // entity being declared.
3223 return ParamLists.back();
3226 void Sema::NoteAllFoundTemplates(TemplateName Name) {
3227 if (TemplateDecl *Template = Name.getAsTemplateDecl()) {
3228 Diag(Template->getLocation(), diag::note_template_declared_here)
3229 << (isa<FunctionTemplateDecl>(Template)
3231 : isa<ClassTemplateDecl>(Template)
3233 : isa<VarTemplateDecl>(Template)
3235 : isa<TypeAliasTemplateDecl>(Template) ? 3 : 4)
3236 << Template->getDeclName();
3240 if (OverloadedTemplateStorage *OST = Name.getAsOverloadedTemplate()) {
3241 for (OverloadedTemplateStorage::iterator I = OST->begin(),
3244 Diag((*I)->getLocation(), diag::note_template_declared_here)
3245 << 0 << (*I)->getDeclName();
3252 checkBuiltinTemplateIdType(Sema &SemaRef, BuiltinTemplateDecl *BTD,
3253 const SmallVectorImpl<TemplateArgument> &Converted,
3254 SourceLocation TemplateLoc,
3255 TemplateArgumentListInfo &TemplateArgs) {
3256 ASTContext &Context = SemaRef.getASTContext();
3257 switch (BTD->getBuiltinTemplateKind()) {
3258 case BTK__make_integer_seq: {
3259 // Specializations of __make_integer_seq<S, T, N> are treated like
3260 // S<T, 0, ..., N-1>.
3262 // C++14 [inteseq.intseq]p1:
3263 // T shall be an integer type.
3264 if (!Converted[1].getAsType()->isIntegralType(Context)) {
3265 SemaRef.Diag(TemplateArgs[1].getLocation(),
3266 diag::err_integer_sequence_integral_element_type);
3270 // C++14 [inteseq.make]p1:
3271 // If N is negative the program is ill-formed.
3272 TemplateArgument NumArgsArg = Converted[2];
3273 llvm::APSInt NumArgs = NumArgsArg.getAsIntegral();
3275 SemaRef.Diag(TemplateArgs[2].getLocation(),
3276 diag::err_integer_sequence_negative_length);
3280 QualType ArgTy = NumArgsArg.getIntegralType();
3281 TemplateArgumentListInfo SyntheticTemplateArgs;
3282 // The type argument gets reused as the first template argument in the
3283 // synthetic template argument list.
3284 SyntheticTemplateArgs.addArgument(TemplateArgs[1]);
3285 // Expand N into 0 ... N-1.
3286 for (llvm::APSInt I(NumArgs.getBitWidth(), NumArgs.isUnsigned());
3288 TemplateArgument TA(Context, I, ArgTy);
3289 SyntheticTemplateArgs.addArgument(SemaRef.getTrivialTemplateArgumentLoc(
3290 TA, ArgTy, TemplateArgs[2].getLocation()));
3292 // The first template argument will be reused as the template decl that
3293 // our synthetic template arguments will be applied to.
3294 return SemaRef.CheckTemplateIdType(Converted[0].getAsTemplate(),
3295 TemplateLoc, SyntheticTemplateArgs);
3298 case BTK__type_pack_element:
3299 // Specializations of
3300 // __type_pack_element<Index, T_1, ..., T_N>
3301 // are treated like T_Index.
3302 assert(Converted.size() == 2 &&
3303 "__type_pack_element should be given an index and a parameter pack");
3305 // If the Index is out of bounds, the program is ill-formed.
3306 TemplateArgument IndexArg = Converted[0], Ts = Converted[1];
3307 llvm::APSInt Index = IndexArg.getAsIntegral();
3308 assert(Index >= 0 && "the index used with __type_pack_element should be of "
3309 "type std::size_t, and hence be non-negative");
3310 if (Index >= Ts.pack_size()) {
3311 SemaRef.Diag(TemplateArgs[0].getLocation(),
3312 diag::err_type_pack_element_out_of_bounds);
3316 // We simply return the type at index `Index`.
3317 auto Nth = std::next(Ts.pack_begin(), Index.getExtValue());
3318 return Nth->getAsType();
3320 llvm_unreachable("unexpected BuiltinTemplateDecl!");
3323 /// Determine whether this alias template is "enable_if_t".
3324 static bool isEnableIfAliasTemplate(TypeAliasTemplateDecl *AliasTemplate) {
3325 return AliasTemplate->getName().equals("enable_if_t");
3328 /// Collect all of the separable terms in the given condition, which
3329 /// might be a conjunction.
3331 /// FIXME: The right answer is to convert the logical expression into
3332 /// disjunctive normal form, so we can find the first failed term
3333 /// within each possible clause.
3334 static void collectConjunctionTerms(Expr *Clause,
3335 SmallVectorImpl<Expr *> &Terms) {
3336 if (auto BinOp = dyn_cast<BinaryOperator>(Clause->IgnoreParenImpCasts())) {
3337 if (BinOp->getOpcode() == BO_LAnd) {
3338 collectConjunctionTerms(BinOp->getLHS(), Terms);
3339 collectConjunctionTerms(BinOp->getRHS(), Terms);
3345 Terms.push_back(Clause);
3348 // The ranges-v3 library uses an odd pattern of a top-level "||" with
3349 // a left-hand side that is value-dependent but never true. Identify
3350 // the idiom and ignore that term.
3351 static Expr *lookThroughRangesV3Condition(Preprocessor &PP, Expr *Cond) {
3353 auto *BinOp = dyn_cast<BinaryOperator>(Cond->IgnoreParenImpCasts());
3354 if (!BinOp) return Cond;
3356 if (BinOp->getOpcode() != BO_LOr) return Cond;
3358 // With an inner '==' that has a literal on the right-hand side.
3359 Expr *LHS = BinOp->getLHS();
3360 auto *InnerBinOp = dyn_cast<BinaryOperator>(LHS->IgnoreParenImpCasts());
3361 if (!InnerBinOp) return Cond;
3363 if (InnerBinOp->getOpcode() != BO_EQ ||
3364 !isa<IntegerLiteral>(InnerBinOp->getRHS()))
3367 // If the inner binary operation came from a macro expansion named
3368 // CONCEPT_REQUIRES or CONCEPT_REQUIRES_, return the right-hand side
3369 // of the '||', which is the real, user-provided condition.
3370 SourceLocation Loc = InnerBinOp->getExprLoc();
3371 if (!Loc.isMacroID()) return Cond;
3373 StringRef MacroName = PP.getImmediateMacroName(Loc);
3374 if (MacroName == "CONCEPT_REQUIRES" || MacroName == "CONCEPT_REQUIRES_")
3375 return BinOp->getRHS();
3382 // A PrinterHelper that prints more helpful diagnostics for some sub-expressions
3383 // within failing boolean expression, such as substituting template parameters
3384 // for actual types.
3385 class FailedBooleanConditionPrinterHelper : public PrinterHelper {
3387 explicit FailedBooleanConditionPrinterHelper(const PrintingPolicy &P)
3390 bool handledStmt(Stmt *E, raw_ostream &OS) override {
3391 const auto *DR = dyn_cast<DeclRefExpr>(E);
3392 if (DR && DR->getQualifier()) {
3393 // If this is a qualified name, expand the template arguments in nested
3395 DR->getQualifier()->print(OS, Policy, true);
3396 // Then print the decl itself.
3397 const ValueDecl *VD = DR->getDecl();
3398 OS << VD->getName();
3399 if (const auto *IV = dyn_cast<VarTemplateSpecializationDecl>(VD)) {
3400 // This is a template variable, print the expanded template arguments.
3401 printTemplateArgumentList(OS, IV->getTemplateArgs().asArray(), Policy);
3409 const PrintingPolicy Policy;
3412 } // end anonymous namespace
3414 std::pair<Expr *, std::string>
3415 Sema::findFailedBooleanCondition(Expr *Cond) {
3416 Cond = lookThroughRangesV3Condition(PP, Cond);
3418 // Separate out all of the terms in a conjunction.
3419 SmallVector<Expr *, 4> Terms;
3420 collectConjunctionTerms(Cond, Terms);
3422 // Determine which term failed.
3423 Expr *FailedCond = nullptr;
3424 for (Expr *Term : Terms) {
3425 Expr *TermAsWritten = Term->IgnoreParenImpCasts();
3427 // Literals are uninteresting.
3428 if (isa<CXXBoolLiteralExpr>(TermAsWritten) ||
3429 isa<IntegerLiteral>(TermAsWritten))
3432 // The initialization of the parameter from the argument is
3433 // a constant-evaluated context.
3434 EnterExpressionEvaluationContext ConstantEvaluated(
3435 *this, Sema::ExpressionEvaluationContext::ConstantEvaluated);
3438 if (Term->EvaluateAsBooleanCondition(Succeeded, Context) &&
3440 FailedCond = TermAsWritten;
3445 FailedCond = Cond->IgnoreParenImpCasts();
3447 std::string Description;
3449 llvm::raw_string_ostream Out(Description);
3450 PrintingPolicy Policy = getPrintingPolicy();
3451 Policy.PrintCanonicalTypes = true;
3452 FailedBooleanConditionPrinterHelper Helper(Policy);
3453 FailedCond->printPretty(Out, &Helper, Policy, 0, "\n", nullptr);
3455 return { FailedCond, Description };
3458 QualType Sema::CheckTemplateIdType(TemplateName Name,
3459 SourceLocation TemplateLoc,
3460 TemplateArgumentListInfo &TemplateArgs) {
3461 DependentTemplateName *DTN
3462 = Name.getUnderlying().getAsDependentTemplateName();
3463 if (DTN && DTN->isIdentifier())
3464 // When building a template-id where the template-name is dependent,
3465 // assume the template is a type template. Either our assumption is
3466 // correct, or the code is ill-formed and will be diagnosed when the
3467 // dependent name is substituted.
3468 return Context.getDependentTemplateSpecializationType(ETK_None,
3469 DTN->getQualifier(),
3470 DTN->getIdentifier(),
3473 TemplateDecl *Template = Name.getAsTemplateDecl();
3474 if (!Template || isa<FunctionTemplateDecl>(Template) ||
3475 isa<VarTemplateDecl>(Template) || isa<ConceptDecl>(Template)) {
3476 // We might have a substituted template template parameter pack. If so,
3477 // build a template specialization type for it.
3478 if (Name.getAsSubstTemplateTemplateParmPack())
3479 return Context.getTemplateSpecializationType(Name, TemplateArgs);
3481 Diag(TemplateLoc, diag::err_template_id_not_a_type)
3483 NoteAllFoundTemplates(Name);
3487 // Check that the template argument list is well-formed for this
3489 SmallVector<TemplateArgument, 4> Converted;
3490 if (CheckTemplateArgumentList(Template, TemplateLoc, TemplateArgs,
3492 /*UpdateArgsWithConversion=*/true))
3497 bool InstantiationDependent = false;
3498 if (TypeAliasTemplateDecl *AliasTemplate =
3499 dyn_cast<TypeAliasTemplateDecl>(Template)) {
3501 // Find the canonical type for this type alias template specialization.
3502 TypeAliasDecl *Pattern = AliasTemplate->getTemplatedDecl();
3503 if (Pattern->isInvalidDecl())
3506 TemplateArgumentList StackTemplateArgs(TemplateArgumentList::OnStack,
3509 // Only substitute for the innermost template argument list.
3510 MultiLevelTemplateArgumentList TemplateArgLists;
3511 TemplateArgLists.addOuterTemplateArguments(&StackTemplateArgs);
3512 unsigned Depth = AliasTemplate->getTemplateParameters()->getDepth();
3513 for (unsigned I = 0; I < Depth; ++I)
3514 TemplateArgLists.addOuterTemplateArguments(None);
3516 LocalInstantiationScope Scope(*this);
3517 InstantiatingTemplate Inst(*this, TemplateLoc, Template);
3518 if (Inst.isInvalid())
3521 CanonType = SubstType(Pattern->getUnderlyingType(),
3522 TemplateArgLists, AliasTemplate->getLocation(),
3523 AliasTemplate->getDeclName());
3524 if (CanonType.isNull()) {
3525 // If this was enable_if and we failed to find the nested type
3526 // within enable_if in a SFINAE context, dig out the specific
3527 // enable_if condition that failed and present that instead.
3528 if (isEnableIfAliasTemplate(AliasTemplate)) {
3529 if (auto DeductionInfo = isSFINAEContext()) {
3530 if (*DeductionInfo &&
3531 (*DeductionInfo)->hasSFINAEDiagnostic() &&
3532 (*DeductionInfo)->peekSFINAEDiagnostic().second.getDiagID() ==
3533 diag::err_typename_nested_not_found_enable_if &&
3534 TemplateArgs[0].getArgument().getKind()
3535 == TemplateArgument::Expression) {
3537 std::string FailedDescription;
3538 std::tie(FailedCond, FailedDescription) =
3539 findFailedBooleanCondition(TemplateArgs[0].getSourceExpression());
3541 // Remove the old SFINAE diagnostic.
3542 PartialDiagnosticAt OldDiag =
3543 {SourceLocation(), PartialDiagnostic::NullDiagnostic()};
3544 (*DeductionInfo)->takeSFINAEDiagnostic(OldDiag);
3546 // Add a new SFINAE diagnostic specifying which condition
3548 (*DeductionInfo)->addSFINAEDiagnostic(
3550 PDiag(diag::err_typename_nested_not_found_requirement)
3551 << FailedDescription
3552 << FailedCond->getSourceRange());
3559 } else if (Name.isDependent() ||
3560 TemplateSpecializationType::anyDependentTemplateArguments(
3561 TemplateArgs, InstantiationDependent)) {
3562 // This class template specialization is a dependent
3563 // type. Therefore, its canonical type is another class template
3564 // specialization type that contains all of the converted
3565 // arguments in canonical form. This ensures that, e.g., A<T> and
3566 // A<T, T> have identical types when A is declared as:
3568 // template<typename T, typename U = T> struct A;
3569 CanonType = Context.getCanonicalTemplateSpecializationType(Name, Converted);
3571 // This might work out to be a current instantiation, in which
3572 // case the canonical type needs to be the InjectedClassNameType.
3574 // TODO: in theory this could be a simple hashtable lookup; most
3575 // changes to CurContext don't change the set of current
3577 if (isa<ClassTemplateDecl>(Template)) {
3578 for (DeclContext *Ctx = CurContext; Ctx; Ctx = Ctx->getLookupParent()) {
3579 // If we get out to a namespace, we're done.
3580 if (Ctx->isFileContext()) break;
3582 // If this isn't a record, keep looking.
3583 CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(Ctx);
3584 if (!Record) continue;
3586 // Look for one of the two cases with InjectedClassNameTypes
3587 // and check whether it's the same template.
3588 if (!isa<ClassTemplatePartialSpecializationDecl>(Record) &&
3589 !Record->getDescribedClassTemplate())
3592 // Fetch the injected class name type and check whether its
3593 // injected type is equal to the type we just built.
3594 QualType ICNT = Context.getTypeDeclType(Record);
3595 QualType Injected = cast<InjectedClassNameType>(ICNT)
3596 ->getInjectedSpecializationType();
3598 if (CanonType != Injected->getCanonicalTypeInternal())
3601 // If so, the canonical type of this TST is the injected
3602 // class name type of the record we just found.
3603 assert(ICNT.isCanonical());
3608 } else if (ClassTemplateDecl *ClassTemplate
3609 = dyn_cast<ClassTemplateDecl>(Template)) {
3610 // Find the class template specialization declaration that
3611 // corresponds to these arguments.
3612 void *InsertPos = nullptr;
3613 ClassTemplateSpecializationDecl *Decl
3614 = ClassTemplate->findSpecialization(Converted, InsertPos);
3616 // This is the first time we have referenced this class template
3617 // specialization. Create the canonical declaration and add it to
3618 // the set of specializations.
3619 Decl = ClassTemplateSpecializationDecl::Create(
3620 Context, ClassTemplate->getTemplatedDecl()->getTagKind(),
3621 ClassTemplate->getDeclContext(),
3622 ClassTemplate->getTemplatedDecl()->getBeginLoc(),
3623 ClassTemplate->getLocation(), ClassTemplate, Converted, nullptr);
3624 ClassTemplate->AddSpecialization(Decl, InsertPos);
3625 if (ClassTemplate->isOutOfLine())
3626 Decl->setLexicalDeclContext(ClassTemplate->getLexicalDeclContext());
3629 if (Decl->getSpecializationKind() == TSK_Undeclared) {
3630 MultiLevelTemplateArgumentList TemplateArgLists;
3631 TemplateArgLists.addOuterTemplateArguments(Converted);
3632 InstantiateAttrsForDecl(TemplateArgLists, ClassTemplate->getTemplatedDecl(),
3636 // Diagnose uses of this specialization.
3637 (void)DiagnoseUseOfDecl(Decl, TemplateLoc);
3639 CanonType = Context.getTypeDeclType(Decl);
3640 assert(isa<RecordType>(CanonType) &&
3641 "type of non-dependent specialization is not a RecordType");
3642 } else if (auto *BTD = dyn_cast<BuiltinTemplateDecl>(Template)) {
3643 CanonType = checkBuiltinTemplateIdType(*this, BTD, Converted, TemplateLoc,
3647 // Build the fully-sugared type for this class template
3648 // specialization, which refers back to the class template
3649 // specialization we created or found.
3650 return Context.getTemplateSpecializationType(Name, TemplateArgs, CanonType);
3653 void Sema::ActOnUndeclaredTypeTemplateName(Scope *S, TemplateTy &ParsedName,
3654 TemplateNameKind &TNK,
3655 SourceLocation NameLoc,
3656 IdentifierInfo *&II) {
3657 assert(TNK == TNK_Undeclared_template && "not an undeclared template name");
3659 TemplateName Name = ParsedName.get();
3660 auto *ATN = Name.getAsAssumedTemplateName();
3661 assert(ATN && "not an assumed template name");
3662 II = ATN->getDeclName().getAsIdentifierInfo();
3664 if (!resolveAssumedTemplateNameAsType(S, Name, NameLoc, /*Diagnose*/false)) {
3665 // Resolved to a type template name.
3666 ParsedName = TemplateTy::make(Name);
3667 TNK = TNK_Type_template;
3671 bool Sema::resolveAssumedTemplateNameAsType(Scope *S, TemplateName &Name,
3672 SourceLocation NameLoc,
3674 // We assumed this undeclared identifier to be an (ADL-only) function
3675 // template name, but it was used in a context where a type was required.
3676 // Try to typo-correct it now.
3677 AssumedTemplateStorage *ATN = Name.getAsAssumedTemplateName();
3678 assert(ATN && "not an assumed template name");
3680 LookupResult R(*this, ATN->getDeclName(), NameLoc, LookupOrdinaryName);
3681 struct CandidateCallback : CorrectionCandidateCallback {
3682 bool ValidateCandidate(const TypoCorrection &TC) override {
3683 return TC.getCorrectionDecl() &&
3684 getAsTypeTemplateDecl(TC.getCorrectionDecl());
3686 std::unique_ptr<CorrectionCandidateCallback> clone() override {
3687 return std::make_unique<CandidateCallback>(*this);
3691 TypoCorrection Corrected =
3692 CorrectTypo(R.getLookupNameInfo(), R.getLookupKind(), S, nullptr,
3693 FilterCCC, CTK_ErrorRecovery);
3694 if (Corrected && Corrected.getFoundDecl()) {
3695 diagnoseTypo(Corrected, PDiag(diag::err_no_template_suggest)
3696 << ATN->getDeclName());
3697 Name = TemplateName(Corrected.getCorrectionDeclAs<TemplateDecl>());
3702 Diag(R.getNameLoc(), diag::err_no_template) << R.getLookupName();
3706 TypeResult Sema::ActOnTemplateIdType(
3707 Scope *S, CXXScopeSpec &SS, SourceLocation TemplateKWLoc,
3708 TemplateTy TemplateD, IdentifierInfo *TemplateII,
3709 SourceLocation TemplateIILoc, SourceLocation LAngleLoc,
3710 ASTTemplateArgsPtr TemplateArgsIn, SourceLocation RAngleLoc,
3711 bool IsCtorOrDtorName, bool IsClassName) {
3715 if (!IsCtorOrDtorName && !IsClassName && SS.isSet()) {
3716 DeclContext *LookupCtx = computeDeclContext(SS, /*EnteringContext*/false);
3718 // C++ [temp.res]p3:
3719 // A qualified-id that refers to a type and in which the
3720 // nested-name-specifier depends on a template-parameter (14.6.2)
3721 // shall be prefixed by the keyword typename to indicate that the
3722 // qualified-id denotes a type, forming an
3723 // elaborated-type-specifier (7.1.5.3).
3724 if (!LookupCtx && isDependentScopeSpecifier(SS)) {
3725 Diag(SS.getBeginLoc(), diag::err_typename_missing_template)
3726 << SS.getScopeRep() << TemplateII->getName();
3727 // Recover as if 'typename' were specified.
3728 // FIXME: This is not quite correct recovery as we don't transform SS
3729 // into the corresponding dependent form (and we don't diagnose missing
3730 // 'template' keywords within SS as a result).
3731 return ActOnTypenameType(nullptr, SourceLocation(), SS, TemplateKWLoc,
3732 TemplateD, TemplateII, TemplateIILoc, LAngleLoc,
3733 TemplateArgsIn, RAngleLoc);
3736 // Per C++ [class.qual]p2, if the template-id was an injected-class-name,
3737 // it's not actually allowed to be used as a type in most cases. Because
3738 // we annotate it before we know whether it's valid, we have to check for
3740 auto *LookupRD = dyn_cast_or_null<CXXRecordDecl>(LookupCtx);
3741 if (LookupRD && LookupRD->getIdentifier() == TemplateII) {
3743 TemplateKWLoc.isInvalid()
3744 ? diag::err_out_of_line_qualified_id_type_names_constructor
3745 : diag::ext_out_of_line_qualified_id_type_names_constructor)
3746 << TemplateII << 0 /*injected-class-name used as template name*/
3747 << 1 /*if any keyword was present, it was 'template'*/;
3751 TemplateName Template = TemplateD.get();
3752 if (Template.getAsAssumedTemplateName() &&
3753 resolveAssumedTemplateNameAsType(S, Template, TemplateIILoc))
3756 // Translate the parser's template argument list in our AST format.
3757 TemplateArgumentListInfo TemplateArgs(LAngleLoc, RAngleLoc);
3758 translateTemplateArguments(TemplateArgsIn, TemplateArgs);
3760 if (DependentTemplateName *DTN = Template.getAsDependentTemplateName()) {
3762 = Context.getDependentTemplateSpecializationType(ETK_None,
3763 DTN->getQualifier(),
3764 DTN->getIdentifier(),
3766 // Build type-source information.
3768 DependentTemplateSpecializationTypeLoc SpecTL
3769 = TLB.push<DependentTemplateSpecializationTypeLoc>(T);
3770 SpecTL.setElaboratedKeywordLoc(SourceLocation());
3771 SpecTL.setQualifierLoc(SS.getWithLocInContext(Context));
3772 SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
3773 SpecTL.setTemplateNameLoc(TemplateIILoc);
3774 SpecTL.setLAngleLoc(LAngleLoc);
3775 SpecTL.setRAngleLoc(RAngleLoc);
3776 for (unsigned I = 0, N = SpecTL.getNumArgs(); I != N; ++I)
3777 SpecTL.setArgLocInfo(I, TemplateArgs[I].getLocInfo());
3778 return CreateParsedType(T, TLB.getTypeSourceInfo(Context, T));
3781 QualType Result = CheckTemplateIdType(Template, TemplateIILoc, TemplateArgs);
3782 if (Result.isNull())
3785 // Build type-source information.
3787 TemplateSpecializationTypeLoc SpecTL
3788 = TLB.push<TemplateSpecializationTypeLoc>(Result);
3789 SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
3790 SpecTL.setTemplateNameLoc(TemplateIILoc);
3791 SpecTL.setLAngleLoc(LAngleLoc);
3792 SpecTL.setRAngleLoc(RAngleLoc);
3793 for (unsigned i = 0, e = SpecTL.getNumArgs(); i != e; ++i)
3794 SpecTL.setArgLocInfo(i, TemplateArgs[i].getLocInfo());
3796 // NOTE: avoid constructing an ElaboratedTypeLoc if this is a
3797 // constructor or destructor name (in such a case, the scope specifier
3798 // will be attached to the enclosing Decl or Expr node).
3799 if (SS.isNotEmpty() && !IsCtorOrDtorName) {
3800 // Create an elaborated-type-specifier containing the nested-name-specifier.
3801 Result = Context.getElaboratedType(ETK_None, SS.getScopeRep(), Result);
3802 ElaboratedTypeLoc ElabTL = TLB.push<ElaboratedTypeLoc>(Result);
3803 ElabTL.setElaboratedKeywordLoc(SourceLocation());
3804 ElabTL.setQualifierLoc(SS.getWithLocInContext(Context));
3807 return CreateParsedType(Result, TLB.getTypeSourceInfo(Context, Result));
3810 TypeResult Sema::ActOnTagTemplateIdType(TagUseKind TUK,
3811 TypeSpecifierType TagSpec,
3812 SourceLocation TagLoc,
3814 SourceLocation TemplateKWLoc,
3815 TemplateTy TemplateD,
3816 SourceLocation TemplateLoc,
3817 SourceLocation LAngleLoc,
3818 ASTTemplateArgsPtr TemplateArgsIn,
3819 SourceLocation RAngleLoc) {
3820 TemplateName Template = TemplateD.get();
3822 // Translate the parser's template argument list in our AST format.
3823 TemplateArgumentListInfo TemplateArgs(LAngleLoc, RAngleLoc);
3824 translateTemplateArguments(TemplateArgsIn, TemplateArgs);
3826 // Determine the tag kind
3827 TagTypeKind TagKind = TypeWithKeyword::getTagTypeKindForTypeSpec(TagSpec);
3828 ElaboratedTypeKeyword Keyword
3829 = TypeWithKeyword::getKeywordForTagTypeKind(TagKind);
3831 if (DependentTemplateName *DTN = Template.getAsDependentTemplateName()) {
3832 QualType T = Context.getDependentTemplateSpecializationType(Keyword,
3833 DTN->getQualifier(),
3834 DTN->getIdentifier(),
3837 // Build type-source information.
3839 DependentTemplateSpecializationTypeLoc SpecTL
3840 = TLB.push<DependentTemplateSpecializationTypeLoc>(T);
3841 SpecTL.setElaboratedKeywordLoc(TagLoc);
3842 SpecTL.setQualifierLoc(SS.getWithLocInContext(Context));
3843 SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
3844 SpecTL.setTemplateNameLoc(TemplateLoc);
3845 SpecTL.setLAngleLoc(LAngleLoc);
3846 SpecTL.setRAngleLoc(RAngleLoc);
3847 for (unsigned I = 0, N = SpecTL.getNumArgs(); I != N; ++I)
3848 SpecTL.setArgLocInfo(I, TemplateArgs[I].getLocInfo());
3849 return CreateParsedType(T, TLB.getTypeSourceInfo(Context, T));
3852 if (TypeAliasTemplateDecl *TAT =
3853 dyn_cast_or_null<TypeAliasTemplateDecl>(Template.getAsTemplateDecl())) {
3854 // C++0x [dcl.type.elab]p2:
3855 // If the identifier resolves to a typedef-name or the simple-template-id
3856 // resolves to an alias template specialization, the
3857 // elaborated-type-specifier is ill-formed.
3858 Diag(TemplateLoc, diag::err_tag_reference_non_tag)
3859 << TAT << NTK_TypeAliasTemplate << TagKind;
3860 Diag(TAT->getLocation(), diag::note_declared_at);
3863 QualType Result = CheckTemplateIdType(Template, TemplateLoc, TemplateArgs);
3864 if (Result.isNull())
3865 return TypeResult(true);
3867 // Check the tag kind
3868 if (const RecordType *RT = Result->getAs<RecordType>()) {
3869 RecordDecl *D = RT->getDecl();
3871 IdentifierInfo *Id = D->getIdentifier();
3872 assert(Id && "templated class must have an identifier");
3874 if (!isAcceptableTagRedeclaration(D, TagKind, TUK == TUK_Definition,
3876 Diag(TagLoc, diag::err_use_with_wrong_tag)
3878 << FixItHint::CreateReplacement(SourceRange(TagLoc), D->getKindName());
3879 Diag(D->getLocation(), diag::note_previous_use);
3883 // Provide source-location information for the template specialization.
3885 TemplateSpecializationTypeLoc SpecTL
3886 = TLB.push<TemplateSpecializationTypeLoc>(Result);
3887 SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
3888 SpecTL.setTemplateNameLoc(TemplateLoc);
3889 SpecTL.setLAngleLoc(LAngleLoc);
3890 SpecTL.setRAngleLoc(RAngleLoc);
3891 for (unsigned i = 0, e = SpecTL.getNumArgs(); i != e; ++i)
3892 SpecTL.setArgLocInfo(i, TemplateArgs[i].getLocInfo());
3894 // Construct an elaborated type containing the nested-name-specifier (if any)
3896 Result = Context.getElaboratedType(Keyword, SS.getScopeRep(), Result);
3897 ElaboratedTypeLoc ElabTL = TLB.push<ElaboratedTypeLoc>(Result);
3898 ElabTL.setElaboratedKeywordLoc(TagLoc);
3899 ElabTL.setQualifierLoc(SS.getWithLocInContext(Context));
3900 return CreateParsedType(Result, TLB.getTypeSourceInfo(Context, Result));
3903 static bool CheckTemplateSpecializationScope(Sema &S, NamedDecl *Specialized,
3904 NamedDecl *PrevDecl,
3906 bool IsPartialSpecialization);
3908 static TemplateSpecializationKind getTemplateSpecializationKind(Decl *D);
3910 static bool isTemplateArgumentTemplateParameter(
3911 const TemplateArgument &Arg, unsigned Depth, unsigned Index) {
3912 switch (Arg.getKind()) {
3913 case TemplateArgument::Null:
3914 case TemplateArgument::NullPtr:
3915 case TemplateArgument::Integral:
3916 case TemplateArgument::Declaration:
3917 case TemplateArgument::Pack:
3918 case TemplateArgument::TemplateExpansion:
3921 case TemplateArgument::Type: {
3922 QualType Type = Arg.getAsType();
3923 const TemplateTypeParmType *TPT =
3924 Arg.getAsType()->getAs<TemplateTypeParmType>();
3925 return TPT && !Type.hasQualifiers() &&
3926 TPT->getDepth() == Depth && TPT->getIndex() == Index;
3929 case TemplateArgument::Expression: {
3930 DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Arg.getAsExpr());
3931 if (!DRE || !DRE->getDecl())
3933 const NonTypeTemplateParmDecl *NTTP =
3934 dyn_cast<NonTypeTemplateParmDecl>(DRE->getDecl());
3935 return NTTP && NTTP->getDepth() == Depth && NTTP->getIndex() == Index;
3938 case TemplateArgument::Template:
3939 const TemplateTemplateParmDecl *TTP =
3940 dyn_cast_or_null<TemplateTemplateParmDecl>(
3941 Arg.getAsTemplateOrTemplatePattern().getAsTemplateDecl());
3942 return TTP && TTP->getDepth() == Depth && TTP->getIndex() == Index;
3944 llvm_unreachable("unexpected kind of template argument");
3947 static bool isSameAsPrimaryTemplate(TemplateParameterList *Params,
3948 ArrayRef<TemplateArgument> Args) {
3949 if (Params->size() != Args.size())
3952 unsigned Depth = Params->getDepth();
3954 for (unsigned I = 0, N = Args.size(); I != N; ++I) {
3955 TemplateArgument Arg = Args[I];
3957 // If the parameter is a pack expansion, the argument must be a pack
3958 // whose only element is a pack expansion.
3959 if (Params->getParam(I)->isParameterPack()) {
3960 if (Arg.getKind() != TemplateArgument::Pack || Arg.pack_size() != 1 ||
3961 !Arg.pack_begin()->isPackExpansion())
3963 Arg = Arg.pack_begin()->getPackExpansionPattern();
3966 if (!isTemplateArgumentTemplateParameter(Arg, Depth, I))
3973 template<typename PartialSpecDecl>
3974 static void checkMoreSpecializedThanPrimary(Sema &S, PartialSpecDecl *Partial) {
3975 if (Partial->getDeclContext()->isDependentContext())
3978 // FIXME: Get the TDK from deduction in order to provide better diagnostics
3979 // for non-substitution-failure issues?
3980 TemplateDeductionInfo Info(Partial->getLocation());
3981 if (S.isMoreSpecializedThanPrimary(Partial, Info))
3984 auto *Template = Partial->getSpecializedTemplate();
3985 S.Diag(Partial->getLocation(),
3986 diag::ext_partial_spec_not_more_specialized_than_primary)
3987 << isa<VarTemplateDecl>(Template);
3989 if (Info.hasSFINAEDiagnostic()) {
3990 PartialDiagnosticAt Diag = {SourceLocation(),
3991 PartialDiagnostic::NullDiagnostic()};
3992 Info.takeSFINAEDiagnostic(Diag);
3993 SmallString<128> SFINAEArgString;
3994 Diag.second.EmitToString(S.getDiagnostics(), SFINAEArgString);
3996 diag::note_partial_spec_not_more_specialized_than_primary)
4000 S.Diag(Template->getLocation(), diag::note_template_decl_here);
4001 SmallVector<const Expr *, 3> PartialAC, TemplateAC;
4002 Template->getAssociatedConstraints(TemplateAC);
4003 Partial->getAssociatedConstraints(PartialAC);
4004 S.MaybeEmitAmbiguousAtomicConstraintsDiagnostic(Partial, PartialAC, Template,
4009 noteNonDeducibleParameters(Sema &S, TemplateParameterList *TemplateParams,
4010 const llvm::SmallBitVector &DeducibleParams) {
4011 for (unsigned I = 0, N = DeducibleParams.size(); I != N; ++I) {
4012 if (!DeducibleParams[I]) {
4013 NamedDecl *Param = TemplateParams->getParam(I);
4014 if (Param->getDeclName())
4015 S.Diag(Param->getLocation(), diag::note_non_deducible_parameter)
4016 << Param->getDeclName();
4018 S.Diag(Param->getLocation(), diag::note_non_deducible_parameter)
4025 template<typename PartialSpecDecl>
4026 static void checkTemplatePartialSpecialization(Sema &S,
4027 PartialSpecDecl *Partial) {
4028 // C++1z [temp.class.spec]p8: (DR1495)
4029 // - The specialization shall be more specialized than the primary
4030 // template (14.5.5.2).
4031 checkMoreSpecializedThanPrimary(S, Partial);
4033 // C++ [temp.class.spec]p8: (DR1315)
4034 // - Each template-parameter shall appear at least once in the
4035 // template-id outside a non-deduced context.
4036 // C++1z [temp.class.spec.match]p3 (P0127R2)
4037 // If the template arguments of a partial specialization cannot be
4038 // deduced because of the structure of its template-parameter-list
4039 // and the template-id, the program is ill-formed.
4040 auto *TemplateParams = Partial->getTemplateParameters();
4041 llvm::SmallBitVector DeducibleParams(TemplateParams->size());
4042 S.MarkUsedTemplateParameters(Partial->getTemplateArgs(), true,
4043 TemplateParams->getDepth(), DeducibleParams);
4045 if (!DeducibleParams.all()) {
4046 unsigned NumNonDeducible = DeducibleParams.size() - DeducibleParams.count();
4047 S.Diag(Partial->getLocation(), diag::ext_partial_specs_not_deducible)
4048 << isa<VarTemplatePartialSpecializationDecl>(Partial)
4049 << (NumNonDeducible > 1)
4050 << SourceRange(Partial->getLocation(),
4051 Partial->getTemplateArgsAsWritten()->RAngleLoc);
4052 noteNonDeducibleParameters(S, TemplateParams, DeducibleParams);
4056 void Sema::CheckTemplatePartialSpecialization(
4057 ClassTemplatePartialSpecializationDecl *Partial) {
4058 checkTemplatePartialSpecialization(*this, Partial);
4061 void Sema::CheckTemplatePartialSpecialization(
4062 VarTemplatePartialSpecializationDecl *Partial) {
4063 checkTemplatePartialSpecialization(*this, Partial);
4066 void Sema::CheckDeductionGuideTemplate(FunctionTemplateDecl *TD) {
4067 // C++1z [temp.param]p11:
4068 // A template parameter of a deduction guide template that does not have a
4069 // default-argument shall be deducible from the parameter-type-list of the
4070 // deduction guide template.
4071 auto *TemplateParams = TD->getTemplateParameters();
4072 llvm::SmallBitVector DeducibleParams(TemplateParams->size());
4073 MarkDeducedTemplateParameters(TD, DeducibleParams);
4074 for (unsigned I = 0; I != TemplateParams->size(); ++I) {
4075 // A parameter pack is deducible (to an empty pack).
4076 auto *Param = TemplateParams->getParam(I);
4077 if (Param->isParameterPack() || hasVisibleDefaultArgument(Param))
4078 DeducibleParams[I] = true;
4081 if (!DeducibleParams.all()) {
4082 unsigned NumNonDeducible = DeducibleParams.size() - DeducibleParams.count();
4083 Diag(TD->getLocation(), diag::err_deduction_guide_template_not_deducible)
4084 << (NumNonDeducible > 1);
4085 noteNonDeducibleParameters(*this, TemplateParams, DeducibleParams);
4089 DeclResult Sema::ActOnVarTemplateSpecialization(
4090 Scope *S, Declarator &D, TypeSourceInfo *DI, SourceLocation TemplateKWLoc,
4091 TemplateParameterList *TemplateParams, StorageClass SC,
4092 bool IsPartialSpecialization) {
4093 // D must be variable template id.
4094 assert(D.getName().getKind() == UnqualifiedIdKind::IK_TemplateId &&
4095 "Variable template specialization is declared with a template it.");
4097 TemplateIdAnnotation *TemplateId = D.getName().TemplateId;
4098 TemplateArgumentListInfo TemplateArgs =
4099 makeTemplateArgumentListInfo(*this, *TemplateId);
4100 SourceLocation TemplateNameLoc = D.getIdentifierLoc();
4101 SourceLocation LAngleLoc = TemplateId->LAngleLoc;
4102 SourceLocation RAngleLoc = TemplateId->RAngleLoc;
4104 TemplateName Name = TemplateId->Template.get();
4106 // The template-id must name a variable template.
4107 VarTemplateDecl *VarTemplate =
4108 dyn_cast_or_null<VarTemplateDecl>(Name.getAsTemplateDecl());
4110 NamedDecl *FnTemplate;
4111 if (auto *OTS = Name.getAsOverloadedTemplate())
4112 FnTemplate = *OTS->begin();
4114 FnTemplate = dyn_cast_or_null<FunctionTemplateDecl>(Name.getAsTemplateDecl());
4116 return Diag(D.getIdentifierLoc(), diag::err_var_spec_no_template_but_method)
4117 << FnTemplate->getDeclName();
4118 return Diag(D.getIdentifierLoc(), diag::err_var_spec_no_template)
4119 << IsPartialSpecialization;
4122 // Check for unexpanded parameter packs in any of the template arguments.
4123 for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I)
4124 if (DiagnoseUnexpandedParameterPack(TemplateArgs[I],
4125 UPPC_PartialSpecialization))
4128 // Check that the template argument list is well-formed for this
4130 SmallVector<TemplateArgument, 4> Converted;
4131 if (CheckTemplateArgumentList(VarTemplate, TemplateNameLoc, TemplateArgs,
4133 /*UpdateArgsWithConversion=*/true))
4136 // Find the variable template (partial) specialization declaration that
4137 // corresponds to these arguments.
4138 if (IsPartialSpecialization) {
4139 if (CheckTemplatePartialSpecializationArgs(TemplateNameLoc, VarTemplate,
4140 TemplateArgs.size(), Converted))
4143 // FIXME: Move these checks to CheckTemplatePartialSpecializationArgs so we
4144 // also do them during instantiation.
4145 bool InstantiationDependent;
4146 if (!Name.isDependent() &&
4147 !TemplateSpecializationType::anyDependentTemplateArguments(
4148 TemplateArgs.arguments(),
4149 InstantiationDependent)) {
4150 Diag(TemplateNameLoc, diag::err_partial_spec_fully_specialized)
4151 << VarTemplate->getDeclName();
4152 IsPartialSpecialization = false;
4155 if (isSameAsPrimaryTemplate(VarTemplate->getTemplateParameters(),
4157 (!Context.getLangOpts().CPlusPlus2a ||
4158 !TemplateParams->hasAssociatedConstraints())) {
4159 // C++ [temp.class.spec]p9b3:
4161 // -- The argument list of the specialization shall not be identical
4162 // to the implicit argument list of the primary template.
4163 Diag(TemplateNameLoc, diag::err_partial_spec_args_match_primary_template)
4164 << /*variable template*/ 1
4165 << /*is definition*/(SC != SC_Extern && !CurContext->isRecord())
4166 << FixItHint::CreateRemoval(SourceRange(LAngleLoc, RAngleLoc));
4167 // FIXME: Recover from this by treating the declaration as a redeclaration
4168 // of the primary template.
4173 void *InsertPos = nullptr;
4174 VarTemplateSpecializationDecl *PrevDecl = nullptr;
4176 if (IsPartialSpecialization)
4177 PrevDecl = VarTemplate->findPartialSpecialization(Converted, TemplateParams,
4180 PrevDecl = VarTemplate->findSpecialization(Converted, InsertPos);
4182 VarTemplateSpecializationDecl *Specialization = nullptr;
4184 // Check whether we can declare a variable template specialization in
4185 // the current scope.
4186 if (CheckTemplateSpecializationScope(*this, VarTemplate, PrevDecl,
4188 IsPartialSpecialization))
4191 if (PrevDecl && PrevDecl->getSpecializationKind() == TSK_Undeclared) {
4192 // Since the only prior variable template specialization with these
4193 // arguments was referenced but not declared, reuse that
4194 // declaration node as our own, updating its source location and
4195 // the list of outer template parameters to reflect our new declaration.
4196 Specialization = PrevDecl;
4197 Specialization->setLocation(TemplateNameLoc);
4199 } else if (IsPartialSpecialization) {
4200 // Create a new class template partial specialization declaration node.
4201 VarTemplatePartialSpecializationDecl *PrevPartial =
4202 cast_or_null<VarTemplatePartialSpecializationDecl>(PrevDecl);
4203 VarTemplatePartialSpecializationDecl *Partial =
4204 VarTemplatePartialSpecializationDecl::Create(
4205 Context, VarTemplate->getDeclContext(), TemplateKWLoc,
4206 TemplateNameLoc, TemplateParams, VarTemplate, DI->getType(), DI, SC,
4207 Converted, TemplateArgs);
4210 VarTemplate->AddPartialSpecialization(Partial, InsertPos);
4211 Specialization = Partial;
4213 // If we are providing an explicit specialization of a member variable
4214 // template specialization, make a note of that.
4215 if (PrevPartial && PrevPartial->getInstantiatedFromMember())
4216 PrevPartial->setMemberSpecialization();
4218 CheckTemplatePartialSpecialization(Partial);
4220 // Create a new class template specialization declaration node for
4221 // this explicit specialization or friend declaration.
4222 Specialization = VarTemplateSpecializationDecl::Create(
4223 Context, VarTemplate->getDeclContext(), TemplateKWLoc, TemplateNameLoc,
4224 VarTemplate, DI->getType(), DI, SC, Converted);
4225 Specialization->setTemplateArgsInfo(TemplateArgs);
4228 VarTemplate->AddSpecialization(Specialization, InsertPos);
4231 // C++ [temp.expl.spec]p6:
4232 // If a template, a member template or the member of a class template is
4233 // explicitly specialized then that specialization shall be declared
4234 // before the first use of that specialization that would cause an implicit
4235 // instantiation to take place, in every translation unit in which such a
4236 // use occurs; no diagnostic is required.
4237 if (PrevDecl && PrevDecl->getPointOfInstantiation().isValid()) {
4239 for (Decl *Prev = PrevDecl; Prev; Prev = Prev->getPreviousDecl()) {
4240 // Is there any previous explicit specialization declaration?
4241 if (getTemplateSpecializationKind(Prev) == TSK_ExplicitSpecialization) {
4248 SourceRange Range(TemplateNameLoc, RAngleLoc);
4249 Diag(TemplateNameLoc, diag::err_specialization_after_instantiation)
4252 Diag(PrevDecl->getPointOfInstantiation(),
4253 diag::note_instantiation_required_here)
4254 << (PrevDecl->getTemplateSpecializationKind() !=
4255 TSK_ImplicitInstantiation);
4260 Specialization->setTemplateKeywordLoc(TemplateKWLoc);
4261 Specialization->setLexicalDeclContext(CurContext);
4263 // Add the specialization into its lexical context, so that it can
4264 // be seen when iterating through the list of declarations in that
4265 // context. However, specializations are not found by name lookup.
4266 CurContext->addDecl(Specialization);
4268 // Note that this is an explicit specialization.
4269 Specialization->setSpecializationKind(TSK_ExplicitSpecialization);
4272 // Check that this isn't a redefinition of this specialization,
4273 // merging with previous declarations.
4274 LookupResult PrevSpec(*this, GetNameForDeclarator(D), LookupOrdinaryName,
4275 forRedeclarationInCurContext());
4276 PrevSpec.addDecl(PrevDecl);
4277 D.setRedeclaration(CheckVariableDeclaration(Specialization, PrevSpec));
4278 } else if (Specialization->isStaticDataMember() &&
4279 Specialization->isOutOfLine()) {
4280 Specialization->setAccess(VarTemplate->getAccess());
4283 return Specialization;
4287 /// A partial specialization whose template arguments have matched
4288 /// a given template-id.
4289 struct PartialSpecMatchResult {
4290 VarTemplatePartialSpecializationDecl *Partial;
4291 TemplateArgumentList *Args;
4293 } // end anonymous namespace
4296 Sema::CheckVarTemplateId(VarTemplateDecl *Template, SourceLocation TemplateLoc,
4297 SourceLocation TemplateNameLoc,
4298 const TemplateArgumentListInfo &TemplateArgs) {
4299 assert(Template && "A variable template id without template?");
4301 // Check that the template argument list is well-formed for this template.
4302 SmallVector<TemplateArgument, 4> Converted;
4303 if (CheckTemplateArgumentList(
4304 Template, TemplateNameLoc,
4305 const_cast<TemplateArgumentListInfo &>(TemplateArgs), false,
4306 Converted, /*UpdateArgsWithConversion=*/true))
4309 // Find the variable template specialization declaration that
4310 // corresponds to these arguments.
4311 void *InsertPos = nullptr;
4312 if (VarTemplateSpecializationDecl *Spec = Template->findSpecialization(
4313 Converted, InsertPos)) {
4314 checkSpecializationVisibility(TemplateNameLoc, Spec);
4315 // If we already have a variable template specialization, return it.
4319 // This is the first time we have referenced this variable template
4320 // specialization. Create the canonical declaration and add it to
4321 // the set of specializations, based on the closest partial specialization
4322 // that it represents. That is,
4323 VarDecl *InstantiationPattern = Template->getTemplatedDecl();
4324 TemplateArgumentList TemplateArgList(TemplateArgumentList::OnStack,
4326 TemplateArgumentList *InstantiationArgs = &TemplateArgList;
4327 bool AmbiguousPartialSpec = false;
4328 typedef PartialSpecMatchResult MatchResult;
4329 SmallVector<MatchResult, 4> Matched;
4330 SourceLocation PointOfInstantiation = TemplateNameLoc;
4331 TemplateSpecCandidateSet FailedCandidates(PointOfInstantiation,
4332 /*ForTakingAddress=*/false);
4334 // 1. Attempt to find the closest partial specialization that this
4335 // specializes, if any.
4336 // If any of the template arguments is dependent, then this is probably
4337 // a placeholder for an incomplete declarative context; which must be
4338 // complete by instantiation time. Thus, do not search through the partial
4339 // specializations yet.
4340 // TODO: Unify with InstantiateClassTemplateSpecialization()?
4341 // Perhaps better after unification of DeduceTemplateArguments() and
4342 // getMoreSpecializedPartialSpecialization().
4343 bool InstantiationDependent = false;
4344 if (!TemplateSpecializationType::anyDependentTemplateArguments(
4345 TemplateArgs, InstantiationDependent)) {
4347 SmallVector<VarTemplatePartialSpecializationDecl *, 4> PartialSpecs;
4348 Template->getPartialSpecializations(PartialSpecs);
4350 for (unsigned I = 0, N = PartialSpecs.size(); I != N; ++I) {
4351 VarTemplatePartialSpecializationDecl *Partial = PartialSpecs[I];
4352 TemplateDeductionInfo Info(FailedCandidates.getLocation());
4354 if (TemplateDeductionResult Result =
4355 DeduceTemplateArguments(Partial, TemplateArgList, Info)) {
4356 // Store the failed-deduction information for use in diagnostics, later.
4357 // TODO: Actually use the failed-deduction info?
4358 FailedCandidates.addCandidate().set(
4359 DeclAccessPair::make(Template, AS_public), Partial,
4360 MakeDeductionFailureInfo(Context, Result, Info));
4363 Matched.push_back(PartialSpecMatchResult());
4364 Matched.back().Partial = Partial;
4365 Matched.back().Args = Info.take();
4369 if (Matched.size() >= 1) {
4370 SmallVector<MatchResult, 4>::iterator Best = Matched.begin();
4371 if (Matched.size() == 1) {
4372 // -- If exactly one matching specialization is found, the
4373 // instantiation is generated from that specialization.
4374 // We don't need to do anything for this.
4376 // -- If more than one matching specialization is found, the
4377 // partial order rules (14.5.4.2) are used to determine
4378 // whether one of the specializations is more specialized
4379 // than the others. If none of the specializations is more
4380 // specialized than all of the other matching
4381 // specializations, then the use of the variable template is
4382 // ambiguous and the program is ill-formed.
4383 for (SmallVector<MatchResult, 4>::iterator P = Best + 1,
4384 PEnd = Matched.end();
4386 if (getMoreSpecializedPartialSpecialization(P->Partial, Best->Partial,
4387 PointOfInstantiation) ==
4392 // Determine if the best partial specialization is more specialized than
4394 for (SmallVector<MatchResult, 4>::iterator P = Matched.begin(),
4395 PEnd = Matched.end();
4397 if (P != Best && getMoreSpecializedPartialSpecialization(
4398 P->Partial, Best->Partial,
4399 PointOfInstantiation) != Best->Partial) {
4400 AmbiguousPartialSpec = true;
4406 // Instantiate using the best variable template partial specialization.
4407 InstantiationPattern = Best->Partial;
4408 InstantiationArgs = Best->Args;
4410 // -- If no match is found, the instantiation is generated
4411 // from the primary template.
4412 // InstantiationPattern = Template->getTemplatedDecl();
4416 // 2. Create the canonical declaration.
4417 // Note that we do not instantiate a definition until we see an odr-use
4418 // in DoMarkVarDeclReferenced().
4419 // FIXME: LateAttrs et al.?
4420 VarTemplateSpecializationDecl *Decl = BuildVarTemplateInstantiation(
4421 Template, InstantiationPattern, *InstantiationArgs, TemplateArgs,
4422 Converted, TemplateNameLoc, InsertPos /*, LateAttrs, StartingScope*/);
4426 if (AmbiguousPartialSpec) {
4427 // Partial ordering did not produce a clear winner. Complain.
4428 Decl->setInvalidDecl();
4429 Diag(PointOfInstantiation, diag::err_partial_spec_ordering_ambiguous)
4432 // Print the matching partial specializations.
4433 for (MatchResult P : Matched)
4434 Diag(P.Partial->getLocation(), diag::note_partial_spec_match)
4435 << getTemplateArgumentBindingsText(P.Partial->getTemplateParameters(),
4440 if (VarTemplatePartialSpecializationDecl *D =
4441 dyn_cast<VarTemplatePartialSpecializationDecl>(InstantiationPattern))
4442 Decl->setInstantiationOf(D, InstantiationArgs);
4444 checkSpecializationVisibility(TemplateNameLoc, Decl);
4446 assert(Decl && "No variable template specialization?");
4451 Sema::CheckVarTemplateId(const CXXScopeSpec &SS,
4452 const DeclarationNameInfo &NameInfo,
4453 VarTemplateDecl *Template, SourceLocation TemplateLoc,
4454 const TemplateArgumentListInfo *TemplateArgs) {
4456 DeclResult Decl = CheckVarTemplateId(Template, TemplateLoc, NameInfo.getLoc(),
4458 if (Decl.isInvalid())
4461 VarDecl *Var = cast<VarDecl>(Decl.get());
4462 if (!Var->getTemplateSpecializationKind())
4463 Var->setTemplateSpecializationKind(TSK_ImplicitInstantiation,
4466 // Build an ordinary singleton decl ref.
4467 return BuildDeclarationNameExpr(SS, NameInfo, Var,
4468 /*FoundD=*/nullptr, TemplateArgs);
4471 void Sema::diagnoseMissingTemplateArguments(TemplateName Name,
4472 SourceLocation Loc) {
4473 Diag(Loc, diag::err_template_missing_args)
4474 << (int)getTemplateNameKindForDiagnostics(Name) << Name;
4475 if (TemplateDecl *TD = Name.getAsTemplateDecl()) {
4476 Diag(TD->getLocation(), diag::note_template_decl_here)
4477 << TD->getTemplateParameters()->getSourceRange();
4482 Sema::CheckConceptTemplateId(const CXXScopeSpec &SS,
4483 SourceLocation TemplateKWLoc,
4484 const DeclarationNameInfo &ConceptNameInfo,
4485 NamedDecl *FoundDecl,
4486 ConceptDecl *NamedConcept,
4487 const TemplateArgumentListInfo *TemplateArgs) {
4488 assert(NamedConcept && "A concept template id without a template?");
4490 llvm::SmallVector<TemplateArgument, 4> Converted;
4491 if (CheckTemplateArgumentList(NamedConcept, ConceptNameInfo.getLoc(),
4492 const_cast<TemplateArgumentListInfo&>(*TemplateArgs),
4493 /*PartialTemplateArgs=*/false, Converted,
4494 /*UpdateArgsWithConversion=*/false))
4497 ConstraintSatisfaction Satisfaction;
4498 bool AreArgsDependent = false;
4499 for (TemplateArgument &Arg : Converted) {
4500 if (Arg.isDependent()) {
4501 AreArgsDependent = true;
4505 if (!AreArgsDependent &&
4506 CheckConstraintSatisfaction(NamedConcept,
4507 {NamedConcept->getConstraintExpr()},
4509 SourceRange(SS.isSet() ? SS.getBeginLoc() :
4510 ConceptNameInfo.getLoc(),
4511 TemplateArgs->getRAngleLoc()),
4515 return ConceptSpecializationExpr::Create(Context,
4516 SS.isSet() ? SS.getWithLocInContext(Context) : NestedNameSpecifierLoc{},
4517 TemplateKWLoc, ConceptNameInfo, FoundDecl, NamedConcept,
4518 ASTTemplateArgumentListInfo::Create(Context, *TemplateArgs), Converted,
4519 AreArgsDependent ? nullptr : &Satisfaction);
4522 ExprResult Sema::BuildTemplateIdExpr(const CXXScopeSpec &SS,
4523 SourceLocation TemplateKWLoc,
4526 const TemplateArgumentListInfo *TemplateArgs) {
4527 // FIXME: Can we do any checking at this point? I guess we could check the
4528 // template arguments that we have against the template name, if the template
4529 // name refers to a single template. That's not a terribly common case,
4531 // foo<int> could identify a single function unambiguously
4532 // This approach does NOT work, since f<int>(1);
4533 // gets resolved prior to resorting to overload resolution
4534 // i.e., template<class T> void f(double);
4535 // vs template<class T, class U> void f(U);
4537 // These should be filtered out by our callers.
4538 assert(!R.isAmbiguous() && "ambiguous lookup when building templateid");
4540 // Non-function templates require a template argument list.
4541 if (auto *TD = R.getAsSingle<TemplateDecl>()) {
4542 if (!TemplateArgs && !isa<FunctionTemplateDecl>(TD)) {
4543 diagnoseMissingTemplateArguments(TemplateName(TD), R.getNameLoc());
4548 auto AnyDependentArguments = [&]() -> bool {
4549 bool InstantiationDependent;
4550 return TemplateArgs &&
4551 TemplateSpecializationType::anyDependentTemplateArguments(
4552 *TemplateArgs, InstantiationDependent);
4555 // In C++1y, check variable template ids.
4556 if (R.getAsSingle<VarTemplateDecl>() && !AnyDependentArguments()) {
4557 return CheckVarTemplateId(SS, R.getLookupNameInfo(),
4558 R.getAsSingle<VarTemplateDecl>(),
4559 TemplateKWLoc, TemplateArgs);
4562 if (R.getAsSingle<ConceptDecl>()) {
4563 return CheckConceptTemplateId(SS, TemplateKWLoc, R.getLookupNameInfo(),
4565 R.getAsSingle<ConceptDecl>(), TemplateArgs);
4568 // We don't want lookup warnings at this point.
4569 R.suppressDiagnostics();
4571 UnresolvedLookupExpr *ULE
4572 = UnresolvedLookupExpr::Create(Context, R.getNamingClass(),
4573 SS.getWithLocInContext(Context),
4575 R.getLookupNameInfo(),
4576 RequiresADL, TemplateArgs,
4577 R.begin(), R.end());
4582 // We actually only call this from template instantiation.
4584 Sema::BuildQualifiedTemplateIdExpr(CXXScopeSpec &SS,
4585 SourceLocation TemplateKWLoc,
4586 const DeclarationNameInfo &NameInfo,
4587 const TemplateArgumentListInfo *TemplateArgs) {
4589 assert(TemplateArgs || TemplateKWLoc.isValid());
4591 if (!(DC = computeDeclContext(SS, false)) ||
4592 DC->isDependentContext() ||
4593 RequireCompleteDeclContext(SS, DC))
4594 return BuildDependentDeclRefExpr(SS, TemplateKWLoc, NameInfo, TemplateArgs);
4596 bool MemberOfUnknownSpecialization;
4597 LookupResult R(*this, NameInfo, LookupOrdinaryName);
4598 if (LookupTemplateName(R, (Scope *)nullptr, SS, QualType(),
4599 /*Entering*/false, MemberOfUnknownSpecialization,
4603 if (R.isAmbiguous())
4607 Diag(NameInfo.getLoc(), diag::err_no_member)
4608 << NameInfo.getName() << DC << SS.getRange();
4612 if (ClassTemplateDecl *Temp = R.getAsSingle<ClassTemplateDecl>()) {
4613 Diag(NameInfo.getLoc(), diag::err_template_kw_refers_to_class_template)
4615 << NameInfo.getName().getAsString() << SS.getRange();
4616 Diag(Temp->getLocation(), diag::note_referenced_class_template);
4620 return BuildTemplateIdExpr(SS, TemplateKWLoc, R, /*ADL*/ false, TemplateArgs);
4623 /// Form a dependent template name.
4625 /// This action forms a dependent template name given the template
4626 /// name and its (presumably dependent) scope specifier. For
4627 /// example, given "MetaFun::template apply", the scope specifier \p
4628 /// SS will be "MetaFun::", \p TemplateKWLoc contains the location
4629 /// of the "template" keyword, and "apply" is the \p Name.
4630 TemplateNameKind Sema::ActOnDependentTemplateName(Scope *S,
4632 SourceLocation TemplateKWLoc,
4633 const UnqualifiedId &Name,
4634 ParsedType ObjectType,
4635 bool EnteringContext,
4637 bool AllowInjectedClassName) {
4638 if (TemplateKWLoc.isValid() && S && !S->getTemplateParamParent())
4640 getLangOpts().CPlusPlus11 ?
4641 diag::warn_cxx98_compat_template_outside_of_template :
4642 diag::ext_template_outside_of_template)
4643 << FixItHint::CreateRemoval(TemplateKWLoc);
4645 DeclContext *LookupCtx = nullptr;
4647 LookupCtx = computeDeclContext(SS, EnteringContext);
4648 if (!LookupCtx && ObjectType)
4649 LookupCtx = computeDeclContext(ObjectType.get());
4651 // C++0x [temp.names]p5:
4652 // If a name prefixed by the keyword template is not the name of
4653 // a template, the program is ill-formed. [Note: the keyword
4654 // template may not be applied to non-template members of class
4655 // templates. -end note ] [ Note: as is the case with the
4656 // typename prefix, the template prefix is allowed in cases
4657 // where it is not strictly necessary; i.e., when the
4658 // nested-name-specifier or the expression on the left of the ->
4659 // or . is not dependent on a template-parameter, or the use
4660 // does not appear in the scope of a template. -end note]
4662 // Note: C++03 was more strict here, because it banned the use of
4663 // the "template" keyword prior to a template-name that was not a
4664 // dependent name. C++ DR468 relaxed this requirement (the
4665 // "template" keyword is now permitted). We follow the C++0x
4666 // rules, even in C++03 mode with a warning, retroactively applying the DR.
4667 bool MemberOfUnknownSpecialization;
4668 TemplateNameKind TNK = isTemplateName(S, SS, TemplateKWLoc.isValid(), Name,
4669 ObjectType, EnteringContext, Result,
4670 MemberOfUnknownSpecialization);
4671 if (TNK == TNK_Non_template && MemberOfUnknownSpecialization) {
4672 // This is a dependent template. Handle it below.
4673 } else if (TNK == TNK_Non_template) {
4674 // Do the lookup again to determine if this is a "nothing found" case or
4675 // a "not a template" case. FIXME: Refactor isTemplateName so we don't
4677 DeclarationNameInfo DNI = GetNameFromUnqualifiedId(Name);
4678 LookupResult R(*this, DNI.getName(), Name.getBeginLoc(),
4679 LookupOrdinaryName);
4681 if (!LookupTemplateName(R, S, SS, ObjectType.get(), EnteringContext,
4682 MOUS, TemplateKWLoc) && !R.isAmbiguous())
4683 Diag(Name.getBeginLoc(), diag::err_no_member)
4684 << DNI.getName() << LookupCtx << SS.getRange();
4685 return TNK_Non_template;
4687 // We found something; return it.
4688 auto *LookupRD = dyn_cast<CXXRecordDecl>(LookupCtx);
4689 if (!AllowInjectedClassName && SS.isSet() && LookupRD &&
4690 Name.getKind() == UnqualifiedIdKind::IK_Identifier &&
4691 Name.Identifier && LookupRD->getIdentifier() == Name.Identifier) {
4692 // C++14 [class.qual]p2:
4693 // In a lookup in which function names are not ignored and the
4694 // nested-name-specifier nominates a class C, if the name specified
4695 // [...] is the injected-class-name of C, [...] the name is instead
4696 // considered to name the constructor
4698 // We don't get here if naming the constructor would be valid, so we
4699 // just reject immediately and recover by treating the
4700 // injected-class-name as naming the template.
4701 Diag(Name.getBeginLoc(),
4702 diag::ext_out_of_line_qualified_id_type_names_constructor)
4704 << 0 /*injected-class-name used as template name*/
4705 << 1 /*'template' keyword was used*/;
4711 NestedNameSpecifier *Qualifier = SS.getScopeRep();
4713 switch (Name.getKind()) {
4714 case UnqualifiedIdKind::IK_Identifier:
4715 Result = TemplateTy::make(Context.getDependentTemplateName(Qualifier,
4717 return TNK_Dependent_template_name;
4719 case UnqualifiedIdKind::IK_OperatorFunctionId:
4720 Result = TemplateTy::make(Context.getDependentTemplateName(Qualifier,
4721 Name.OperatorFunctionId.Operator));
4722 return TNK_Function_template;
4724 case UnqualifiedIdKind::IK_LiteralOperatorId:
4725 llvm_unreachable("literal operator id cannot have a dependent scope");
4731 Diag(Name.getBeginLoc(), diag::err_template_kw_refers_to_non_template)
4732 << GetNameFromUnqualifiedId(Name).getName() << Name.getSourceRange()
4734 return TNK_Non_template;
4737 bool Sema::CheckTemplateTypeArgument(TemplateTypeParmDecl *Param,
4738 TemplateArgumentLoc &AL,
4739 SmallVectorImpl<TemplateArgument> &Converted) {
4740 const TemplateArgument &Arg = AL.getArgument();
4742 TypeSourceInfo *TSI = nullptr;
4744 // Check template type parameter.
4745 switch(Arg.getKind()) {
4746 case TemplateArgument::Type:
4747 // C++ [temp.arg.type]p1:
4748 // A template-argument for a template-parameter which is a
4749 // type shall be a type-id.
4750 ArgType = Arg.getAsType();
4751 TSI = AL.getTypeSourceInfo();
4753 case TemplateArgument::Template:
4754 case TemplateArgument::TemplateExpansion: {
4755 // We have a template type parameter but the template argument
4756 // is a template without any arguments.
4757 SourceRange SR = AL.getSourceRange();
4758 TemplateName Name = Arg.getAsTemplateOrTemplatePattern();
4759 diagnoseMissingTemplateArguments(Name, SR.getEnd());
4762 case TemplateArgument::Expression: {
4763 // We have a template type parameter but the template argument is an
4764 // expression; see if maybe it is missing the "typename" keyword.
4766 DeclarationNameInfo NameInfo;
4768 if (DeclRefExpr *ArgExpr = dyn_cast<DeclRefExpr>(Arg.getAsExpr())) {
4769 SS.Adopt(ArgExpr->getQualifierLoc());
4770 NameInfo = ArgExpr->getNameInfo();
4771 } else if (DependentScopeDeclRefExpr *ArgExpr =
4772 dyn_cast<DependentScopeDeclRefExpr>(Arg.getAsExpr())) {
4773 SS.Adopt(ArgExpr->getQualifierLoc());
4774 NameInfo = ArgExpr->getNameInfo();
4775 } else if (CXXDependentScopeMemberExpr *ArgExpr =
4776 dyn_cast<CXXDependentScopeMemberExpr>(Arg.getAsExpr())) {
4777 if (ArgExpr->isImplicitAccess()) {
4778 SS.Adopt(ArgExpr->getQualifierLoc());
4779 NameInfo = ArgExpr->getMemberNameInfo();
4783 if (auto *II = NameInfo.getName().getAsIdentifierInfo()) {
4784 LookupResult Result(*this, NameInfo, LookupOrdinaryName);
4785 LookupParsedName(Result, CurScope, &SS);
4787 if (Result.getAsSingle<TypeDecl>() ||
4788 Result.getResultKind() ==
4789 LookupResult::NotFoundInCurrentInstantiation) {
4790 // Suggest that the user add 'typename' before the NNS.
4791 SourceLocation Loc = AL.getSourceRange().getBegin();
4792 Diag(Loc, getLangOpts().MSVCCompat
4793 ? diag::ext_ms_template_type_arg_missing_typename
4794 : diag::err_template_arg_must_be_type_suggest)
4795 << FixItHint::CreateInsertion(Loc, "typename ");
4796 Diag(Param->getLocation(), diag::note_template_param_here);
4798 // Recover by synthesizing a type using the location information that we
4801 Context.getDependentNameType(ETK_Typename, SS.getScopeRep(), II);
4803 DependentNameTypeLoc TL = TLB.push<DependentNameTypeLoc>(ArgType);
4804 TL.setElaboratedKeywordLoc(SourceLocation(/*synthesized*/));
4805 TL.setQualifierLoc(SS.getWithLocInContext(Context));
4806 TL.setNameLoc(NameInfo.getLoc());
4807 TSI = TLB.getTypeSourceInfo(Context, ArgType);
4809 // Overwrite our input TemplateArgumentLoc so that we can recover
4811 AL = TemplateArgumentLoc(TemplateArgument(ArgType),
4812 TemplateArgumentLocInfo(TSI));
4821 // We have a template type parameter but the template argument
4823 SourceRange SR = AL.getSourceRange();
4824 Diag(SR.getBegin(), diag::err_template_arg_must_be_type) << SR;
4825 Diag(Param->getLocation(), diag::note_template_param_here);
4831 if (CheckTemplateArgument(Param, TSI))
4834 // Add the converted template type argument.
4835 ArgType = Context.getCanonicalType(ArgType);
4838 // If an explicitly-specified template argument type is a lifetime type
4839 // with no lifetime qualifier, the __strong lifetime qualifier is inferred.
4840 if (getLangOpts().ObjCAutoRefCount &&
4841 ArgType->isObjCLifetimeType() &&
4842 !ArgType.getObjCLifetime()) {
4844 Qs.setObjCLifetime(Qualifiers::OCL_Strong);
4845 ArgType = Context.getQualifiedType(ArgType, Qs);
4848 Converted.push_back(TemplateArgument(ArgType));
4852 /// Substitute template arguments into the default template argument for
4853 /// the given template type parameter.
4855 /// \param SemaRef the semantic analysis object for which we are performing
4856 /// the substitution.
4858 /// \param Template the template that we are synthesizing template arguments
4861 /// \param TemplateLoc the location of the template name that started the
4862 /// template-id we are checking.
4864 /// \param RAngleLoc the location of the right angle bracket ('>') that
4865 /// terminates the template-id.
4867 /// \param Param the template template parameter whose default we are
4868 /// substituting into.
4870 /// \param Converted the list of template arguments provided for template
4871 /// parameters that precede \p Param in the template parameter list.
4872 /// \returns the substituted template argument, or NULL if an error occurred.
4873 static TypeSourceInfo *
4874 SubstDefaultTemplateArgument(Sema &SemaRef,
4875 TemplateDecl *Template,
4876 SourceLocation TemplateLoc,
4877 SourceLocation RAngleLoc,
4878 TemplateTypeParmDecl *Param,
4879 SmallVectorImpl<TemplateArgument> &Converted) {
4880 TypeSourceInfo *ArgType = Param->getDefaultArgumentInfo();
4882 // If the argument type is dependent, instantiate it now based
4883 // on the previously-computed template arguments.
4884 if (ArgType->getType()->isInstantiationDependentType()) {
4885 Sema::InstantiatingTemplate Inst(SemaRef, TemplateLoc,
4886 Param, Template, Converted,
4887 SourceRange(TemplateLoc, RAngleLoc));
4888 if (Inst.isInvalid())
4891 TemplateArgumentList TemplateArgs(TemplateArgumentList::OnStack, Converted);
4893 // Only substitute for the innermost template argument list.
4894 MultiLevelTemplateArgumentList TemplateArgLists;
4895 TemplateArgLists.addOuterTemplateArguments(&TemplateArgs);
4896 for (unsigned i = 0, e = Param->getDepth(); i != e; ++i)
4897 TemplateArgLists.addOuterTemplateArguments(None);
4899 Sema::ContextRAII SavedContext(SemaRef, Template->getDeclContext());
4901 SemaRef.SubstType(ArgType, TemplateArgLists,
4902 Param->getDefaultArgumentLoc(), Param->getDeclName());
4908 /// Substitute template arguments into the default template argument for
4909 /// the given non-type template parameter.
4911 /// \param SemaRef the semantic analysis object for which we are performing
4912 /// the substitution.
4914 /// \param Template the template that we are synthesizing template arguments
4917 /// \param TemplateLoc the location of the template name that started the
4918 /// template-id we are checking.
4920 /// \param RAngleLoc the location of the right angle bracket ('>') that
4921 /// terminates the template-id.
4923 /// \param Param the non-type template parameter whose default we are
4924 /// substituting into.
4926 /// \param Converted the list of template arguments provided for template
4927 /// parameters that precede \p Param in the template parameter list.
4929 /// \returns the substituted template argument, or NULL if an error occurred.
4931 SubstDefaultTemplateArgument(Sema &SemaRef,
4932 TemplateDecl *Template,
4933 SourceLocation TemplateLoc,
4934 SourceLocation RAngleLoc,
4935 NonTypeTemplateParmDecl *Param,
4936 SmallVectorImpl<TemplateArgument> &Converted) {
4937 Sema::InstantiatingTemplate Inst(SemaRef, TemplateLoc,
4938 Param, Template, Converted,
4939 SourceRange(TemplateLoc, RAngleLoc));
4940 if (Inst.isInvalid())
4943 TemplateArgumentList TemplateArgs(TemplateArgumentList::OnStack, Converted);
4945 // Only substitute for the innermost template argument list.
4946 MultiLevelTemplateArgumentList TemplateArgLists;
4947 TemplateArgLists.addOuterTemplateArguments(&TemplateArgs);
4948 for (unsigned i = 0, e = Param->getDepth(); i != e; ++i)
4949 TemplateArgLists.addOuterTemplateArguments(None);
4951 Sema::ContextRAII SavedContext(SemaRef, Template->getDeclContext());
4952 EnterExpressionEvaluationContext ConstantEvaluated(
4953 SemaRef, Sema::ExpressionEvaluationContext::ConstantEvaluated);
4954 return SemaRef.SubstExpr(Param->getDefaultArgument(), TemplateArgLists);
4957 /// Substitute template arguments into the default template argument for
4958 /// the given template template parameter.
4960 /// \param SemaRef the semantic analysis object for which we are performing
4961 /// the substitution.
4963 /// \param Template the template that we are synthesizing template arguments
4966 /// \param TemplateLoc the location of the template name that started the
4967 /// template-id we are checking.
4969 /// \param RAngleLoc the location of the right angle bracket ('>') that
4970 /// terminates the template-id.
4972 /// \param Param the template template parameter whose default we are
4973 /// substituting into.
4975 /// \param Converted the list of template arguments provided for template
4976 /// parameters that precede \p Param in the template parameter list.
4978 /// \param QualifierLoc Will be set to the nested-name-specifier (with
4979 /// source-location information) that precedes the template name.
4981 /// \returns the substituted template argument, or NULL if an error occurred.
4983 SubstDefaultTemplateArgument(Sema &SemaRef,
4984 TemplateDecl *Template,
4985 SourceLocation TemplateLoc,
4986 SourceLocation RAngleLoc,
4987 TemplateTemplateParmDecl *Param,
4988 SmallVectorImpl<TemplateArgument> &Converted,
4989 NestedNameSpecifierLoc &QualifierLoc) {
4990 Sema::InstantiatingTemplate Inst(
4991 SemaRef, TemplateLoc, TemplateParameter(Param), Template, Converted,
4992 SourceRange(TemplateLoc, RAngleLoc));
4993 if (Inst.isInvalid())
4994 return TemplateName();
4996 TemplateArgumentList TemplateArgs(TemplateArgumentList::OnStack, Converted);
4998 // Only substitute for the innermost template argument list.
4999 MultiLevelTemplateArgumentList TemplateArgLists;
5000 TemplateArgLists.addOuterTemplateArguments(&TemplateArgs);
5001 for (unsigned i = 0, e = Param->getDepth(); i != e; ++i)
5002 TemplateArgLists.addOuterTemplateArguments(None);
5004 Sema::ContextRAII SavedContext(SemaRef, Template->getDeclContext());
5005 // Substitute into the nested-name-specifier first,
5006 QualifierLoc = Param->getDefaultArgument().getTemplateQualifierLoc();
5009 SemaRef.SubstNestedNameSpecifierLoc(QualifierLoc, TemplateArgLists);
5011 return TemplateName();
5014 return SemaRef.SubstTemplateName(
5016 Param->getDefaultArgument().getArgument().getAsTemplate(),
5017 Param->getDefaultArgument().getTemplateNameLoc(),
5021 /// If the given template parameter has a default template
5022 /// argument, substitute into that default template argument and
5023 /// return the corresponding template argument.
5025 Sema::SubstDefaultTemplateArgumentIfAvailable(TemplateDecl *Template,
5026 SourceLocation TemplateLoc,
5027 SourceLocation RAngleLoc,
5029 SmallVectorImpl<TemplateArgument>
5031 bool &HasDefaultArg) {
5032 HasDefaultArg = false;
5034 if (TemplateTypeParmDecl *TypeParm = dyn_cast<TemplateTypeParmDecl>(Param)) {
5035 if (!hasVisibleDefaultArgument(TypeParm))
5036 return TemplateArgumentLoc();
5038 HasDefaultArg = true;
5039 TypeSourceInfo *DI = SubstDefaultTemplateArgument(*this, Template,
5045 return TemplateArgumentLoc(TemplateArgument(DI->getType()), DI);
5047 return TemplateArgumentLoc();
5050 if (NonTypeTemplateParmDecl *NonTypeParm
5051 = dyn_cast<NonTypeTemplateParmDecl>(Param)) {
5052 if (!hasVisibleDefaultArgument(NonTypeParm))
5053 return TemplateArgumentLoc();
5055 HasDefaultArg = true;
5056 ExprResult Arg = SubstDefaultTemplateArgument(*this, Template,
5061 if (Arg.isInvalid())
5062 return TemplateArgumentLoc();
5064 Expr *ArgE = Arg.getAs<Expr>();
5065 return TemplateArgumentLoc(TemplateArgument(ArgE), ArgE);
5068 TemplateTemplateParmDecl *TempTempParm
5069 = cast<TemplateTemplateParmDecl>(Param);
5070 if (!hasVisibleDefaultArgument(TempTempParm))
5071 return TemplateArgumentLoc();
5073 HasDefaultArg = true;
5074 NestedNameSpecifierLoc QualifierLoc;
5075 TemplateName TName = SubstDefaultTemplateArgument(*this, Template,
5082 return TemplateArgumentLoc();
5084 return TemplateArgumentLoc(TemplateArgument(TName),
5085 TempTempParm->getDefaultArgument().getTemplateQualifierLoc(),
5086 TempTempParm->getDefaultArgument().getTemplateNameLoc());
5089 /// Convert a template-argument that we parsed as a type into a template, if
5090 /// possible. C++ permits injected-class-names to perform dual service as
5091 /// template template arguments and as template type arguments.
5092 static TemplateArgumentLoc convertTypeTemplateArgumentToTemplate(TypeLoc TLoc) {
5093 // Extract and step over any surrounding nested-name-specifier.
5094 NestedNameSpecifierLoc QualLoc;
5095 if (auto ETLoc = TLoc.getAs<ElaboratedTypeLoc>()) {
5096 if (ETLoc.getTypePtr()->getKeyword() != ETK_None)
5097 return TemplateArgumentLoc();
5099 QualLoc = ETLoc.getQualifierLoc();
5100 TLoc = ETLoc.getNamedTypeLoc();
5103 // If this type was written as an injected-class-name, it can be used as a
5104 // template template argument.
5105 if (auto InjLoc = TLoc.getAs<InjectedClassNameTypeLoc>())
5106 return TemplateArgumentLoc(InjLoc.getTypePtr()->getTemplateName(),
5107 QualLoc, InjLoc.getNameLoc());
5109 // If this type was written as an injected-class-name, it may have been
5110 // converted to a RecordType during instantiation. If the RecordType is
5111 // *not* wrapped in a TemplateSpecializationType and denotes a class
5112 // template specialization, it must have come from an injected-class-name.
5113 if (auto RecLoc = TLoc.getAs<RecordTypeLoc>())
5115 dyn_cast<ClassTemplateSpecializationDecl>(RecLoc.getDecl()))
5116 return TemplateArgumentLoc(TemplateName(CTSD->getSpecializedTemplate()),
5117 QualLoc, RecLoc.getNameLoc());
5119 return TemplateArgumentLoc();
5122 /// Check that the given template argument corresponds to the given
5123 /// template parameter.
5125 /// \param Param The template parameter against which the argument will be
5128 /// \param Arg The template argument, which may be updated due to conversions.
5130 /// \param Template The template in which the template argument resides.
5132 /// \param TemplateLoc The location of the template name for the template
5133 /// whose argument list we're matching.
5135 /// \param RAngleLoc The location of the right angle bracket ('>') that closes
5136 /// the template argument list.
5138 /// \param ArgumentPackIndex The index into the argument pack where this
5139 /// argument will be placed. Only valid if the parameter is a parameter pack.
5141 /// \param Converted The checked, converted argument will be added to the
5142 /// end of this small vector.
5144 /// \param CTAK Describes how we arrived at this particular template argument:
5145 /// explicitly written, deduced, etc.
5147 /// \returns true on error, false otherwise.
5148 bool Sema::CheckTemplateArgument(NamedDecl *Param,
5149 TemplateArgumentLoc &Arg,
5150 NamedDecl *Template,
5151 SourceLocation TemplateLoc,
5152 SourceLocation RAngleLoc,
5153 unsigned ArgumentPackIndex,
5154 SmallVectorImpl<TemplateArgument> &Converted,
5155 CheckTemplateArgumentKind CTAK) {
5156 // Check template type parameters.
5157 if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(Param))
5158 return CheckTemplateTypeArgument(TTP, Arg, Converted);
5160 // Check non-type template parameters.
5161 if (NonTypeTemplateParmDecl *NTTP =dyn_cast<NonTypeTemplateParmDecl>(Param)) {
5162 // Do substitution on the type of the non-type template parameter
5163 // with the template arguments we've seen thus far. But if the
5164 // template has a dependent context then we cannot substitute yet.
5165 QualType NTTPType = NTTP->getType();
5166 if (NTTP->isParameterPack() && NTTP->isExpandedParameterPack())
5167 NTTPType = NTTP->getExpansionType(ArgumentPackIndex);
5169 if (NTTPType->isInstantiationDependentType() &&
5170 !isa<TemplateTemplateParmDecl>(Template) &&
5171 !Template->getDeclContext()->isDependentContext()) {
5172 // Do substitution on the type of the non-type template parameter.
5173 InstantiatingTemplate Inst(*this, TemplateLoc, Template,
5175 SourceRange(TemplateLoc, RAngleLoc));
5176 if (Inst.isInvalid())
5179 TemplateArgumentList TemplateArgs(TemplateArgumentList::OnStack,
5182 // If the parameter is a pack expansion, expand this slice of the pack.
5183 if (auto *PET = NTTPType->getAs<PackExpansionType>()) {
5184 Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(*this,
5186 NTTPType = SubstType(PET->getPattern(),
5187 MultiLevelTemplateArgumentList(TemplateArgs),
5188 NTTP->getLocation(),
5189 NTTP->getDeclName());
5191 NTTPType = SubstType(NTTPType,
5192 MultiLevelTemplateArgumentList(TemplateArgs),
5193 NTTP->getLocation(),
5194 NTTP->getDeclName());
5197 // If that worked, check the non-type template parameter type
5199 if (!NTTPType.isNull())
5200 NTTPType = CheckNonTypeTemplateParameterType(NTTPType,
5201 NTTP->getLocation());
5202 if (NTTPType.isNull())
5206 switch (Arg.getArgument().getKind()) {
5207 case TemplateArgument::Null:
5208 llvm_unreachable("Should never see a NULL template argument here");
5210 case TemplateArgument::Expression: {
5211 TemplateArgument Result;
5212 unsigned CurSFINAEErrors = NumSFINAEErrors;
5214 CheckTemplateArgument(NTTP, NTTPType, Arg.getArgument().getAsExpr(),
5216 if (Res.isInvalid())
5218 // If the current template argument causes an error, give up now.
5219 if (CurSFINAEErrors < NumSFINAEErrors)
5222 // If the resulting expression is new, then use it in place of the
5223 // old expression in the template argument.
5224 if (Res.get() != Arg.getArgument().getAsExpr()) {
5225 TemplateArgument TA(Res.get());
5226 Arg = TemplateArgumentLoc(TA, Res.get());
5229 Converted.push_back(Result);
5233 case TemplateArgument::Declaration:
5234 case TemplateArgument::Integral:
5235 case TemplateArgument::NullPtr:
5236 // We've already checked this template argument, so just copy
5237 // it to the list of converted arguments.
5238 Converted.push_back(Arg.getArgument());
5241 case TemplateArgument::Template:
5242 case TemplateArgument::TemplateExpansion:
5243 // We were given a template template argument. It may not be ill-formed;
5245 if (DependentTemplateName *DTN
5246 = Arg.getArgument().getAsTemplateOrTemplatePattern()
5247 .getAsDependentTemplateName()) {
5248 // We have a template argument such as \c T::template X, which we
5249 // parsed as a template template argument. However, since we now
5250 // know that we need a non-type template argument, convert this
5251 // template name into an expression.
5253 DeclarationNameInfo NameInfo(DTN->getIdentifier(),
5254 Arg.getTemplateNameLoc());
5257 SS.Adopt(Arg.getTemplateQualifierLoc());
5258 // FIXME: the template-template arg was a DependentTemplateName,
5259 // so it was provided with a template keyword. However, its source
5260 // location is not stored in the template argument structure.
5261 SourceLocation TemplateKWLoc;
5262 ExprResult E = DependentScopeDeclRefExpr::Create(
5263 Context, SS.getWithLocInContext(Context), TemplateKWLoc, NameInfo,
5266 // If we parsed the template argument as a pack expansion, create a
5267 // pack expansion expression.
5268 if (Arg.getArgument().getKind() == TemplateArgument::TemplateExpansion){
5269 E = ActOnPackExpansion(E.get(), Arg.getTemplateEllipsisLoc());
5274 TemplateArgument Result;
5275 E = CheckTemplateArgument(NTTP, NTTPType, E.get(), Result);
5279 Converted.push_back(Result);
5283 // We have a template argument that actually does refer to a class
5284 // template, alias template, or template template parameter, and
5285 // therefore cannot be a non-type template argument.
5286 Diag(Arg.getLocation(), diag::err_template_arg_must_be_expr)
5287 << Arg.getSourceRange();
5289 Diag(Param->getLocation(), diag::note_template_param_here);
5292 case TemplateArgument::Type: {
5293 // We have a non-type template parameter but the template
5294 // argument is a type.
5296 // C++ [temp.arg]p2:
5297 // In a template-argument, an ambiguity between a type-id and
5298 // an expression is resolved to a type-id, regardless of the
5299 // form of the corresponding template-parameter.
5301 // We warn specifically about this case, since it can be rather
5302 // confusing for users.
5303 QualType T = Arg.getArgument().getAsType();
5304 SourceRange SR = Arg.getSourceRange();
5305 if (T->isFunctionType())
5306 Diag(SR.getBegin(), diag::err_template_arg_nontype_ambig) << SR << T;
5308 Diag(SR.getBegin(), diag::err_template_arg_must_be_expr) << SR;
5309 Diag(Param->getLocation(), diag::note_template_param_here);
5313 case TemplateArgument::Pack:
5314 llvm_unreachable("Caller must expand template argument packs");
5321 // Check template template parameters.
5322 TemplateTemplateParmDecl *TempParm = cast<TemplateTemplateParmDecl>(Param);
5324 TemplateParameterList *Params = TempParm->getTemplateParameters();
5325 if (TempParm->isExpandedParameterPack())
5326 Params = TempParm->getExpansionTemplateParameters(ArgumentPackIndex);
5328 // Substitute into the template parameter list of the template
5329 // template parameter, since previously-supplied template arguments
5330 // may appear within the template template parameter.
5332 // FIXME: Skip this if the parameters aren't instantiation-dependent.
5334 // Set up a template instantiation context.
5335 LocalInstantiationScope Scope(*this);
5336 InstantiatingTemplate Inst(*this, TemplateLoc, Template,
5337 TempParm, Converted,
5338 SourceRange(TemplateLoc, RAngleLoc));
5339 if (Inst.isInvalid())
5342 TemplateArgumentList TemplateArgs(TemplateArgumentList::OnStack, Converted);
5343 Params = SubstTemplateParams(Params, CurContext,
5344 MultiLevelTemplateArgumentList(TemplateArgs));
5349 // C++1z [temp.local]p1: (DR1004)
5350 // When [the injected-class-name] is used [...] as a template-argument for
5351 // a template template-parameter [...] it refers to the class template
5353 if (Arg.getArgument().getKind() == TemplateArgument::Type) {
5354 TemplateArgumentLoc ConvertedArg = convertTypeTemplateArgumentToTemplate(
5355 Arg.getTypeSourceInfo()->getTypeLoc());
5356 if (!ConvertedArg.getArgument().isNull())
5360 switch (Arg.getArgument().getKind()) {
5361 case TemplateArgument::Null:
5362 llvm_unreachable("Should never see a NULL template argument here");
5364 case TemplateArgument::Template:
5365 case TemplateArgument::TemplateExpansion:
5366 if (CheckTemplateTemplateArgument(TempParm, Params, Arg))
5369 Converted.push_back(Arg.getArgument());
5372 case TemplateArgument::Expression:
5373 case TemplateArgument::Type:
5374 // We have a template template parameter but the template
5375 // argument does not refer to a template.
5376 Diag(Arg.getLocation(), diag::err_template_arg_must_be_template)
5377 << getLangOpts().CPlusPlus11;
5380 case TemplateArgument::Declaration:
5381 llvm_unreachable("Declaration argument with template template parameter");
5382 case TemplateArgument::Integral:
5383 llvm_unreachable("Integral argument with template template parameter");
5384 case TemplateArgument::NullPtr:
5385 llvm_unreachable("Null pointer argument with template template parameter");
5387 case TemplateArgument::Pack:
5388 llvm_unreachable("Caller must expand template argument packs");
5394 /// Check whether the template parameter is a pack expansion, and if so,
5395 /// determine the number of parameters produced by that expansion. For instance:
5398 /// template<typename ...Ts> struct A {
5399 /// template<Ts ...NTs, template<Ts> class ...TTs, typename ...Us> struct B;
5403 /// In \c A<int,int>::B, \c NTs and \c TTs have expanded pack size 2, and \c Us
5404 /// is not a pack expansion, so returns an empty Optional.
5405 static Optional<unsigned> getExpandedPackSize(NamedDecl *Param) {
5406 if (TemplateTypeParmDecl *TTP
5407 = dyn_cast<TemplateTypeParmDecl>(Param)) {
5408 if (TTP->isExpandedParameterPack())
5409 return TTP->getNumExpansionParameters();
5412 if (NonTypeTemplateParmDecl *NTTP
5413 = dyn_cast<NonTypeTemplateParmDecl>(Param)) {
5414 if (NTTP->isExpandedParameterPack())
5415 return NTTP->getNumExpansionTypes();
5418 if (TemplateTemplateParmDecl *TTP
5419 = dyn_cast<TemplateTemplateParmDecl>(Param)) {
5420 if (TTP->isExpandedParameterPack())
5421 return TTP->getNumExpansionTemplateParameters();
5427 /// Diagnose a missing template argument.
5428 template<typename TemplateParmDecl>
5429 static bool diagnoseMissingArgument(Sema &S, SourceLocation Loc,
5431 const TemplateParmDecl *D,
5432 TemplateArgumentListInfo &Args) {
5433 // Dig out the most recent declaration of the template parameter; there may be
5434 // declarations of the template that are more recent than TD.
5435 D = cast<TemplateParmDecl>(cast<TemplateDecl>(TD->getMostRecentDecl())
5436 ->getTemplateParameters()
5437 ->getParam(D->getIndex()));
5439 // If there's a default argument that's not visible, diagnose that we're
5440 // missing a module import.
5441 llvm::SmallVector<Module*, 8> Modules;
5442 if (D->hasDefaultArgument() && !S.hasVisibleDefaultArgument(D, &Modules)) {
5443 S.diagnoseMissingImport(Loc, cast<NamedDecl>(TD),
5444 D->getDefaultArgumentLoc(), Modules,
5445 Sema::MissingImportKind::DefaultArgument,
5450 // FIXME: If there's a more recent default argument that *is* visible,
5451 // diagnose that it was declared too late.
5453 TemplateParameterList *Params = TD->getTemplateParameters();
5455 S.Diag(Loc, diag::err_template_arg_list_different_arity)
5456 << /*not enough args*/0
5457 << (int)S.getTemplateNameKindForDiagnostics(TemplateName(TD))
5459 S.Diag(TD->getLocation(), diag::note_template_decl_here)
5460 << Params->getSourceRange();
5464 /// Check that the given template argument list is well-formed
5465 /// for specializing the given template.
5466 bool Sema::CheckTemplateArgumentList(
5467 TemplateDecl *Template, SourceLocation TemplateLoc,
5468 TemplateArgumentListInfo &TemplateArgs, bool PartialTemplateArgs,
5469 SmallVectorImpl<TemplateArgument> &Converted,
5470 bool UpdateArgsWithConversions, bool *ConstraintsNotSatisfied) {
5472 if (ConstraintsNotSatisfied)
5473 *ConstraintsNotSatisfied = false;
5475 // Make a copy of the template arguments for processing. Only make the
5476 // changes at the end when successful in matching the arguments to the
5478 TemplateArgumentListInfo NewArgs = TemplateArgs;
5480 // Make sure we get the template parameter list from the most
5481 // recentdeclaration, since that is the only one that has is guaranteed to
5482 // have all the default template argument information.
5483 TemplateParameterList *Params =
5484 cast<TemplateDecl>(Template->getMostRecentDecl())
5485 ->getTemplateParameters();
5487 SourceLocation RAngleLoc = NewArgs.getRAngleLoc();
5489 // C++ [temp.arg]p1:
5490 // [...] The type and form of each template-argument specified in
5491 // a template-id shall match the type and form specified for the
5492 // corresponding parameter declared by the template in its
5493 // template-parameter-list.
5494 bool isTemplateTemplateParameter = isa<TemplateTemplateParmDecl>(Template);
5495 SmallVector<TemplateArgument, 2> ArgumentPack;
5496 unsigned ArgIdx = 0, NumArgs = NewArgs.size();
5497 LocalInstantiationScope InstScope(*this, true);
5498 for (TemplateParameterList::iterator Param = Params->begin(),
5499 ParamEnd = Params->end();
5500 Param != ParamEnd; /* increment in loop */) {
5501 // If we have an expanded parameter pack, make sure we don't have too
5503 if (Optional<unsigned> Expansions = getExpandedPackSize(*Param)) {
5504 if (*Expansions == ArgumentPack.size()) {
5505 // We're done with this parameter pack. Pack up its arguments and add
5506 // them to the list.
5507 Converted.push_back(
5508 TemplateArgument::CreatePackCopy(Context, ArgumentPack));
5509 ArgumentPack.clear();
5511 // This argument is assigned to the next parameter.
5514 } else if (ArgIdx == NumArgs && !PartialTemplateArgs) {
5515 // Not enough arguments for this parameter pack.
5516 Diag(TemplateLoc, diag::err_template_arg_list_different_arity)
5517 << /*not enough args*/0
5518 << (int)getTemplateNameKindForDiagnostics(TemplateName(Template))
5520 Diag(Template->getLocation(), diag::note_template_decl_here)
5521 << Params->getSourceRange();
5526 if (ArgIdx < NumArgs) {
5527 // Check the template argument we were given.
5528 if (CheckTemplateArgument(*Param, NewArgs[ArgIdx], Template,
5529 TemplateLoc, RAngleLoc,
5530 ArgumentPack.size(), Converted))
5533 bool PackExpansionIntoNonPack =
5534 NewArgs[ArgIdx].getArgument().isPackExpansion() &&
5535 (!(*Param)->isTemplateParameterPack() || getExpandedPackSize(*Param));
5536 if (PackExpansionIntoNonPack && (isa<TypeAliasTemplateDecl>(Template) ||
5537 isa<ConceptDecl>(Template))) {
5538 // Core issue 1430: we have a pack expansion as an argument to an
5539 // alias template, and it's not part of a parameter pack. This
5540 // can't be canonicalized, so reject it now.
5541 // As for concepts - we cannot normalize constraints where this
5542 // situation exists.
5543 Diag(NewArgs[ArgIdx].getLocation(),
5544 diag::err_template_expansion_into_fixed_list)
5545 << (isa<ConceptDecl>(Template) ? 1 : 0)
5546 << NewArgs[ArgIdx].getSourceRange();
5547 Diag((*Param)->getLocation(), diag::note_template_param_here);
5551 // We're now done with this argument.
5554 if ((*Param)->isTemplateParameterPack()) {
5555 // The template parameter was a template parameter pack, so take the
5556 // deduced argument and place it on the argument pack. Note that we
5557 // stay on the same template parameter so that we can deduce more
5559 ArgumentPack.push_back(Converted.pop_back_val());
5561 // Move to the next template parameter.
5565 // If we just saw a pack expansion into a non-pack, then directly convert
5566 // the remaining arguments, because we don't know what parameters they'll
5568 if (PackExpansionIntoNonPack) {
5569 if (!ArgumentPack.empty()) {
5570 // If we were part way through filling in an expanded parameter pack,
5571 // fall back to just producing individual arguments.
5572 Converted.insert(Converted.end(),
5573 ArgumentPack.begin(), ArgumentPack.end());
5574 ArgumentPack.clear();
5577 while (ArgIdx < NumArgs) {
5578 Converted.push_back(NewArgs[ArgIdx].getArgument());
5588 // If we're checking a partial template argument list, we're done.
5589 if (PartialTemplateArgs) {
5590 if ((*Param)->isTemplateParameterPack() && !ArgumentPack.empty())
5591 Converted.push_back(
5592 TemplateArgument::CreatePackCopy(Context, ArgumentPack));
5596 // If we have a template parameter pack with no more corresponding
5597 // arguments, just break out now and we'll fill in the argument pack below.
5598 if ((*Param)->isTemplateParameterPack()) {
5599 assert(!getExpandedPackSize(*Param) &&
5600 "Should have dealt with this already");
5602 // A non-expanded parameter pack before the end of the parameter list
5603 // only occurs for an ill-formed template parameter list, unless we've
5604 // got a partial argument list for a function template, so just bail out.
5605 if (Param + 1 != ParamEnd)
5608 Converted.push_back(
5609 TemplateArgument::CreatePackCopy(Context, ArgumentPack));
5610 ArgumentPack.clear();
5616 // Check whether we have a default argument.
5617 TemplateArgumentLoc Arg;
5619 // Retrieve the default template argument from the template
5620 // parameter. For each kind of template parameter, we substitute the
5621 // template arguments provided thus far and any "outer" template arguments
5622 // (when the template parameter was part of a nested template) into
5623 // the default argument.
5624 if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(*Param)) {
5625 if (!hasVisibleDefaultArgument(TTP))
5626 return diagnoseMissingArgument(*this, TemplateLoc, Template, TTP,
5629 TypeSourceInfo *ArgType = SubstDefaultTemplateArgument(*this,
5638 Arg = TemplateArgumentLoc(TemplateArgument(ArgType->getType()),
5640 } else if (NonTypeTemplateParmDecl *NTTP
5641 = dyn_cast<NonTypeTemplateParmDecl>(*Param)) {
5642 if (!hasVisibleDefaultArgument(NTTP))
5643 return diagnoseMissingArgument(*this, TemplateLoc, Template, NTTP,
5646 ExprResult E = SubstDefaultTemplateArgument(*this, Template,
5654 Expr *Ex = E.getAs<Expr>();
5655 Arg = TemplateArgumentLoc(TemplateArgument(Ex), Ex);
5657 TemplateTemplateParmDecl *TempParm
5658 = cast<TemplateTemplateParmDecl>(*Param);
5660 if (!hasVisibleDefaultArgument(TempParm))
5661 return diagnoseMissingArgument(*this, TemplateLoc, Template, TempParm,
5664 NestedNameSpecifierLoc QualifierLoc;
5665 TemplateName Name = SubstDefaultTemplateArgument(*this, Template,
5674 Arg = TemplateArgumentLoc(TemplateArgument(Name), QualifierLoc,
5675 TempParm->getDefaultArgument().getTemplateNameLoc());
5678 // Introduce an instantiation record that describes where we are using
5679 // the default template argument. We're not actually instantiating a
5680 // template here, we just create this object to put a note into the
5682 InstantiatingTemplate Inst(*this, RAngleLoc, Template, *Param, Converted,
5683 SourceRange(TemplateLoc, RAngleLoc));
5684 if (Inst.isInvalid())
5687 // Check the default template argument.
5688 if (CheckTemplateArgument(*Param, Arg, Template, TemplateLoc,
5689 RAngleLoc, 0, Converted))
5692 // Core issue 150 (assumed resolution): if this is a template template
5693 // parameter, keep track of the default template arguments from the
5694 // template definition.
5695 if (isTemplateTemplateParameter)
5696 NewArgs.addArgument(Arg);
5698 // Move to the next template parameter and argument.
5703 // If we're performing a partial argument substitution, allow any trailing
5704 // pack expansions; they might be empty. This can happen even if
5705 // PartialTemplateArgs is false (the list of arguments is complete but
5706 // still dependent).
5707 if (ArgIdx < NumArgs && CurrentInstantiationScope &&
5708 CurrentInstantiationScope->getPartiallySubstitutedPack()) {
5709 while (ArgIdx < NumArgs && NewArgs[ArgIdx].getArgument().isPackExpansion())
5710 Converted.push_back(NewArgs[ArgIdx++].getArgument());
5713 // If we have any leftover arguments, then there were too many arguments.
5714 // Complain and fail.
5715 if (ArgIdx < NumArgs) {
5716 Diag(TemplateLoc, diag::err_template_arg_list_different_arity)
5717 << /*too many args*/1
5718 << (int)getTemplateNameKindForDiagnostics(TemplateName(Template))
5720 << SourceRange(NewArgs[ArgIdx].getLocation(), NewArgs.getRAngleLoc());
5721 Diag(Template->getLocation(), diag::note_template_decl_here)
5722 << Params->getSourceRange();
5726 // No problems found with the new argument list, propagate changes back
5728 if (UpdateArgsWithConversions)
5729 TemplateArgs = std::move(NewArgs);
5731 if (!PartialTemplateArgs &&
5732 EnsureTemplateArgumentListConstraints(
5733 Template, Converted, SourceRange(TemplateLoc,
5734 TemplateArgs.getRAngleLoc()))) {
5735 if (ConstraintsNotSatisfied)
5736 *ConstraintsNotSatisfied = true;
5744 class UnnamedLocalNoLinkageFinder
5745 : public TypeVisitor<UnnamedLocalNoLinkageFinder, bool>
5750 typedef TypeVisitor<UnnamedLocalNoLinkageFinder, bool> inherited;
5753 UnnamedLocalNoLinkageFinder(Sema &S, SourceRange SR) : S(S), SR(SR) { }
5755 bool Visit(QualType T) {
5756 return T.isNull() ? false : inherited::Visit(T.getTypePtr());
5759 #define TYPE(Class, Parent) \
5760 bool Visit##Class##Type(const Class##Type *);
5761 #define ABSTRACT_TYPE(Class, Parent) \
5762 bool Visit##Class##Type(const Class##Type *) { return false; }
5763 #define NON_CANONICAL_TYPE(Class, Parent) \
5764 bool Visit##Class##Type(const Class##Type *) { return false; }
5765 #include "clang/AST/TypeNodes.inc"
5767 bool VisitTagDecl(const TagDecl *Tag);
5768 bool VisitNestedNameSpecifier(NestedNameSpecifier *NNS);
5770 } // end anonymous namespace
5772 bool UnnamedLocalNoLinkageFinder::VisitBuiltinType(const BuiltinType*) {
5776 bool UnnamedLocalNoLinkageFinder::VisitComplexType(const ComplexType* T) {
5777 return Visit(T->getElementType());
5780 bool UnnamedLocalNoLinkageFinder::VisitPointerType(const PointerType* T) {
5781 return Visit(T->getPointeeType());
5784 bool UnnamedLocalNoLinkageFinder::VisitBlockPointerType(
5785 const BlockPointerType* T) {
5786 return Visit(T->getPointeeType());
5789 bool UnnamedLocalNoLinkageFinder::VisitLValueReferenceType(
5790 const LValueReferenceType* T) {
5791 return Visit(T->getPointeeType());
5794 bool UnnamedLocalNoLinkageFinder::VisitRValueReferenceType(
5795 const RValueReferenceType* T) {
5796 return Visit(T->getPointeeType());
5799 bool UnnamedLocalNoLinkageFinder::VisitMemberPointerType(
5800 const MemberPointerType* T) {
5801 return Visit(T->getPointeeType()) || Visit(QualType(T->getClass(), 0));
5804 bool UnnamedLocalNoLinkageFinder::VisitConstantArrayType(
5805 const ConstantArrayType* T) {
5806 return Visit(T->getElementType());
5809 bool UnnamedLocalNoLinkageFinder::VisitIncompleteArrayType(
5810 const IncompleteArrayType* T) {
5811 return Visit(T->getElementType());
5814 bool UnnamedLocalNoLinkageFinder::VisitVariableArrayType(
5815 const VariableArrayType* T) {
5816 return Visit(T->getElementType());
5819 bool UnnamedLocalNoLinkageFinder::VisitDependentSizedArrayType(
5820 const DependentSizedArrayType* T) {
5821 return Visit(T->getElementType());
5824 bool UnnamedLocalNoLinkageFinder::VisitDependentSizedExtVectorType(
5825 const DependentSizedExtVectorType* T) {
5826 return Visit(T->getElementType());
5829 bool UnnamedLocalNoLinkageFinder::VisitDependentAddressSpaceType(
5830 const DependentAddressSpaceType *T) {
5831 return Visit(T->getPointeeType());
5834 bool UnnamedLocalNoLinkageFinder::VisitVectorType(const VectorType* T) {
5835 return Visit(T->getElementType());
5838 bool UnnamedLocalNoLinkageFinder::VisitDependentVectorType(
5839 const DependentVectorType *T) {
5840 return Visit(T->getElementType());
5843 bool UnnamedLocalNoLinkageFinder::VisitExtVectorType(const ExtVectorType* T) {
5844 return Visit(T->getElementType());
5847 bool UnnamedLocalNoLinkageFinder::VisitFunctionProtoType(
5848 const FunctionProtoType* T) {
5849 for (const auto &A : T->param_types()) {
5854 return Visit(T->getReturnType());
5857 bool UnnamedLocalNoLinkageFinder::VisitFunctionNoProtoType(
5858 const FunctionNoProtoType* T) {
5859 return Visit(T->getReturnType());
5862 bool UnnamedLocalNoLinkageFinder::VisitUnresolvedUsingType(
5863 const UnresolvedUsingType*) {
5867 bool UnnamedLocalNoLinkageFinder::VisitTypeOfExprType(const TypeOfExprType*) {
5871 bool UnnamedLocalNoLinkageFinder::VisitTypeOfType(const TypeOfType* T) {
5872 return Visit(T->getUnderlyingType());
5875 bool UnnamedLocalNoLinkageFinder::VisitDecltypeType(const DecltypeType*) {
5879 bool UnnamedLocalNoLinkageFinder::VisitUnaryTransformType(
5880 const UnaryTransformType*) {
5884 bool UnnamedLocalNoLinkageFinder::VisitAutoType(const AutoType *T) {
5885 return Visit(T->getDeducedType());
5888 bool UnnamedLocalNoLinkageFinder::VisitDeducedTemplateSpecializationType(
5889 const DeducedTemplateSpecializationType *T) {
5890 return Visit(T->getDeducedType());
5893 bool UnnamedLocalNoLinkageFinder::VisitRecordType(const RecordType* T) {
5894 return VisitTagDecl(T->getDecl());
5897 bool UnnamedLocalNoLinkageFinder::VisitEnumType(const EnumType* T) {
5898 return VisitTagDecl(T->getDecl());
5901 bool UnnamedLocalNoLinkageFinder::VisitTemplateTypeParmType(
5902 const TemplateTypeParmType*) {
5906 bool UnnamedLocalNoLinkageFinder::VisitSubstTemplateTypeParmPackType(
5907 const SubstTemplateTypeParmPackType *) {
5911 bool UnnamedLocalNoLinkageFinder::VisitTemplateSpecializationType(
5912 const TemplateSpecializationType*) {
5916 bool UnnamedLocalNoLinkageFinder::VisitInjectedClassNameType(
5917 const InjectedClassNameType* T) {
5918 return VisitTagDecl(T->getDecl());
5921 bool UnnamedLocalNoLinkageFinder::VisitDependentNameType(
5922 const DependentNameType* T) {
5923 return VisitNestedNameSpecifier(T->getQualifier());
5926 bool UnnamedLocalNoLinkageFinder::VisitDependentTemplateSpecializationType(
5927 const DependentTemplateSpecializationType* T) {
5928 return VisitNestedNameSpecifier(T->getQualifier());
5931 bool UnnamedLocalNoLinkageFinder::VisitPackExpansionType(
5932 const PackExpansionType* T) {
5933 return Visit(T->getPattern());
5936 bool UnnamedLocalNoLinkageFinder::VisitObjCObjectType(const ObjCObjectType *) {
5940 bool UnnamedLocalNoLinkageFinder::VisitObjCInterfaceType(
5941 const ObjCInterfaceType *) {
5945 bool UnnamedLocalNoLinkageFinder::VisitObjCObjectPointerType(
5946 const ObjCObjectPointerType *) {
5950 bool UnnamedLocalNoLinkageFinder::VisitAtomicType(const AtomicType* T) {
5951 return Visit(T->getValueType());
5954 bool UnnamedLocalNoLinkageFinder::VisitPipeType(const PipeType* T) {
5958 bool UnnamedLocalNoLinkageFinder::VisitTagDecl(const TagDecl *Tag) {
5959 if (Tag->getDeclContext()->isFunctionOrMethod()) {
5960 S.Diag(SR.getBegin(),
5961 S.getLangOpts().CPlusPlus11 ?
5962 diag::warn_cxx98_compat_template_arg_local_type :
5963 diag::ext_template_arg_local_type)
5964 << S.Context.getTypeDeclType(Tag) << SR;
5968 if (!Tag->hasNameForLinkage()) {
5969 S.Diag(SR.getBegin(),
5970 S.getLangOpts().CPlusPlus11 ?
5971 diag::warn_cxx98_compat_template_arg_unnamed_type :
5972 diag::ext_template_arg_unnamed_type) << SR;
5973 S.Diag(Tag->getLocation(), diag::note_template_unnamed_type_here);
5980 bool UnnamedLocalNoLinkageFinder::VisitNestedNameSpecifier(
5981 NestedNameSpecifier *NNS) {
5982 if (NNS->getPrefix() && VisitNestedNameSpecifier(NNS->getPrefix()))
5985 switch (NNS->getKind()) {
5986 case NestedNameSpecifier::Identifier:
5987 case NestedNameSpecifier::Namespace:
5988 case NestedNameSpecifier::NamespaceAlias:
5989 case NestedNameSpecifier::Global:
5990 case NestedNameSpecifier::Super:
5993 case NestedNameSpecifier::TypeSpec:
5994 case NestedNameSpecifier::TypeSpecWithTemplate:
5995 return Visit(QualType(NNS->getAsType(), 0));
5997 llvm_unreachable("Invalid NestedNameSpecifier::Kind!");
6000 /// Check a template argument against its corresponding
6001 /// template type parameter.
6003 /// This routine implements the semantics of C++ [temp.arg.type]. It
6004 /// returns true if an error occurred, and false otherwise.
6005 bool Sema::CheckTemplateArgument(TemplateTypeParmDecl *Param,
6006 TypeSourceInfo *ArgInfo) {
6007 assert(ArgInfo && "invalid TypeSourceInfo");
6008 QualType Arg = ArgInfo->getType();
6009 SourceRange SR = ArgInfo->getTypeLoc().getSourceRange();
6011 if (Arg->isVariablyModifiedType()) {
6012 return Diag(SR.getBegin(), diag::err_variably_modified_template_arg) << Arg;
6013 } else if (Context.hasSameUnqualifiedType(Arg, Context.OverloadTy)) {
6014 return Diag(SR.getBegin(), diag::err_template_arg_overload_type) << SR;
6017 // C++03 [temp.arg.type]p2:
6018 // A local type, a type with no linkage, an unnamed type or a type
6019 // compounded from any of these types shall not be used as a
6020 // template-argument for a template type-parameter.
6022 // C++11 allows these, and even in C++03 we allow them as an extension with
6024 if (LangOpts.CPlusPlus11 || Arg->hasUnnamedOrLocalType()) {
6025 UnnamedLocalNoLinkageFinder Finder(*this, SR);
6026 (void)Finder.Visit(Context.getCanonicalType(Arg));
6032 enum NullPointerValueKind {
6038 /// Determine whether the given template argument is a null pointer
6039 /// value of the appropriate type.
6040 static NullPointerValueKind
6041 isNullPointerValueTemplateArgument(Sema &S, NonTypeTemplateParmDecl *Param,
6042 QualType ParamType, Expr *Arg,
6043 Decl *Entity = nullptr) {
6044 if (Arg->isValueDependent() || Arg->isTypeDependent())
6045 return NPV_NotNullPointer;
6047 // dllimport'd entities aren't constant but are available inside of template
6049 if (Entity && Entity->hasAttr<DLLImportAttr>())
6050 return NPV_NotNullPointer;
6052 if (!S.isCompleteType(Arg->getExprLoc(), ParamType))
6054 "Incomplete parameter type in isNullPointerValueTemplateArgument!");
6056 if (!S.getLangOpts().CPlusPlus11)
6057 return NPV_NotNullPointer;
6059 // Determine whether we have a constant expression.
6060 ExprResult ArgRV = S.DefaultFunctionArrayConversion(Arg);
6061 if (ArgRV.isInvalid())
6065 Expr::EvalResult EvalResult;
6066 SmallVector<PartialDiagnosticAt, 8> Notes;
6067 EvalResult.Diag = &Notes;
6068 if (!Arg->EvaluateAsRValue(EvalResult, S.Context) ||
6069 EvalResult.HasSideEffects) {
6070 SourceLocation DiagLoc = Arg->getExprLoc();
6072 // If our only note is the usual "invalid subexpression" note, just point
6073 // the caret at its location rather than producing an essentially
6075 if (Notes.size() == 1 && Notes[0].second.getDiagID() ==
6076 diag::note_invalid_subexpr_in_const_expr) {
6077 DiagLoc = Notes[0].first;
6081 S.Diag(DiagLoc, diag::err_template_arg_not_address_constant)
6082 << Arg->getType() << Arg->getSourceRange();
6083 for (unsigned I = 0, N = Notes.size(); I != N; ++I)
6084 S.Diag(Notes[I].first, Notes[I].second);
6086 S.Diag(Param->getLocation(), diag::note_template_param_here);
6090 // C++11 [temp.arg.nontype]p1:
6091 // - an address constant expression of type std::nullptr_t
6092 if (Arg->getType()->isNullPtrType())
6093 return NPV_NullPointer;
6095 // - a constant expression that evaluates to a null pointer value (4.10); or
6096 // - a constant expression that evaluates to a null member pointer value
6098 if ((EvalResult.Val.isLValue() && !EvalResult.Val.getLValueBase()) ||
6099 (EvalResult.Val.isMemberPointer() &&
6100 !EvalResult.Val.getMemberPointerDecl())) {
6101 // If our expression has an appropriate type, we've succeeded.
6102 bool ObjCLifetimeConversion;
6103 if (S.Context.hasSameUnqualifiedType(Arg->getType(), ParamType) ||
6104 S.IsQualificationConversion(Arg->getType(), ParamType, false,
6105 ObjCLifetimeConversion))
6106 return NPV_NullPointer;
6108 // The types didn't match, but we know we got a null pointer; complain,
6109 // then recover as if the types were correct.
6110 S.Diag(Arg->getExprLoc(), diag::err_template_arg_wrongtype_null_constant)
6111 << Arg->getType() << ParamType << Arg->getSourceRange();
6112 S.Diag(Param->getLocation(), diag::note_template_param_here);
6113 return NPV_NullPointer;
6116 // If we don't have a null pointer value, but we do have a NULL pointer
6117 // constant, suggest a cast to the appropriate type.
6118 if (Arg->isNullPointerConstant(S.Context, Expr::NPC_NeverValueDependent)) {
6119 std::string Code = "static_cast<" + ParamType.getAsString() + ">(";
6120 S.Diag(Arg->getExprLoc(), diag::err_template_arg_untyped_null_constant)
6121 << ParamType << FixItHint::CreateInsertion(Arg->getBeginLoc(), Code)
6122 << FixItHint::CreateInsertion(S.getLocForEndOfToken(Arg->getEndLoc()),
6124 S.Diag(Param->getLocation(), diag::note_template_param_here);
6125 return NPV_NullPointer;
6128 // FIXME: If we ever want to support general, address-constant expressions
6129 // as non-type template arguments, we should return the ExprResult here to
6130 // be interpreted by the caller.
6131 return NPV_NotNullPointer;
6134 /// Checks whether the given template argument is compatible with its
6135 /// template parameter.
6136 static bool CheckTemplateArgumentIsCompatibleWithParameter(
6137 Sema &S, NonTypeTemplateParmDecl *Param, QualType ParamType, Expr *ArgIn,
6138 Expr *Arg, QualType ArgType) {
6139 bool ObjCLifetimeConversion;
6140 if (ParamType->isPointerType() &&
6141 !ParamType->castAs<PointerType>()->getPointeeType()->isFunctionType() &&
6142 S.IsQualificationConversion(ArgType, ParamType, false,
6143 ObjCLifetimeConversion)) {
6144 // For pointer-to-object types, qualification conversions are
6147 if (const ReferenceType *ParamRef = ParamType->getAs<ReferenceType>()) {
6148 if (!ParamRef->getPointeeType()->isFunctionType()) {
6149 // C++ [temp.arg.nontype]p5b3:
6150 // For a non-type template-parameter of type reference to
6151 // object, no conversions apply. The type referred to by the
6152 // reference may be more cv-qualified than the (otherwise
6153 // identical) type of the template- argument. The
6154 // template-parameter is bound directly to the
6155 // template-argument, which shall be an lvalue.
6157 // FIXME: Other qualifiers?
6158 unsigned ParamQuals = ParamRef->getPointeeType().getCVRQualifiers();
6159 unsigned ArgQuals = ArgType.getCVRQualifiers();
6161 if ((ParamQuals | ArgQuals) != ParamQuals) {
6162 S.Diag(Arg->getBeginLoc(),
6163 diag::err_template_arg_ref_bind_ignores_quals)
6164 << ParamType << Arg->getType() << Arg->getSourceRange();
6165 S.Diag(Param->getLocation(), diag::note_template_param_here);
6171 // At this point, the template argument refers to an object or
6172 // function with external linkage. We now need to check whether the
6173 // argument and parameter types are compatible.
6174 if (!S.Context.hasSameUnqualifiedType(ArgType,
6175 ParamType.getNonReferenceType())) {
6176 // We can't perform this conversion or binding.
6177 if (ParamType->isReferenceType())
6178 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_no_ref_bind)
6179 << ParamType << ArgIn->getType() << Arg->getSourceRange();
6181 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_not_convertible)
6182 << ArgIn->getType() << ParamType << Arg->getSourceRange();
6183 S.Diag(Param->getLocation(), diag::note_template_param_here);
6191 /// Checks whether the given template argument is the address
6192 /// of an object or function according to C++ [temp.arg.nontype]p1.
6194 CheckTemplateArgumentAddressOfObjectOrFunction(Sema &S,
6195 NonTypeTemplateParmDecl *Param,
6198 TemplateArgument &Converted) {
6199 bool Invalid = false;
6201 QualType ArgType = Arg->getType();
6203 bool AddressTaken = false;
6204 SourceLocation AddrOpLoc;
6205 if (S.getLangOpts().MicrosoftExt) {
6206 // Microsoft Visual C++ strips all casts, allows an arbitrary number of
6207 // dereference and address-of operators.
6208 Arg = Arg->IgnoreParenCasts();
6210 bool ExtWarnMSTemplateArg = false;
6211 UnaryOperatorKind FirstOpKind;
6212 SourceLocation FirstOpLoc;
6213 while (UnaryOperator *UnOp = dyn_cast<UnaryOperator>(Arg)) {
6214 UnaryOperatorKind UnOpKind = UnOp->getOpcode();
6215 if (UnOpKind == UO_Deref)
6216 ExtWarnMSTemplateArg = true;
6217 if (UnOpKind == UO_AddrOf || UnOpKind == UO_Deref) {
6218 Arg = UnOp->getSubExpr()->IgnoreParenCasts();
6219 if (!AddrOpLoc.isValid()) {
6220 FirstOpKind = UnOpKind;
6221 FirstOpLoc = UnOp->getOperatorLoc();
6226 if (FirstOpLoc.isValid()) {
6227 if (ExtWarnMSTemplateArg)
6228 S.Diag(ArgIn->getBeginLoc(), diag::ext_ms_deref_template_argument)
6229 << ArgIn->getSourceRange();
6231 if (FirstOpKind == UO_AddrOf)
6232 AddressTaken = true;
6233 else if (Arg->getType()->isPointerType()) {
6234 // We cannot let pointers get dereferenced here, that is obviously not a
6235 // constant expression.
6236 assert(FirstOpKind == UO_Deref);
6237 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_not_decl_ref)
6238 << Arg->getSourceRange();
6242 // See through any implicit casts we added to fix the type.
6243 Arg = Arg->IgnoreImpCasts();
6245 // C++ [temp.arg.nontype]p1:
6247 // A template-argument for a non-type, non-template
6248 // template-parameter shall be one of: [...]
6250 // -- the address of an object or function with external
6251 // linkage, including function templates and function
6252 // template-ids but excluding non-static class members,
6253 // expressed as & id-expression where the & is optional if
6254 // the name refers to a function or array, or if the
6255 // corresponding template-parameter is a reference; or
6257 // In C++98/03 mode, give an extension warning on any extra parentheses.
6258 // See http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#773
6259 bool ExtraParens = false;
6260 while (ParenExpr *Parens = dyn_cast<ParenExpr>(Arg)) {
6261 if (!Invalid && !ExtraParens) {
6262 S.Diag(Arg->getBeginLoc(),
6263 S.getLangOpts().CPlusPlus11
6264 ? diag::warn_cxx98_compat_template_arg_extra_parens
6265 : diag::ext_template_arg_extra_parens)
6266 << Arg->getSourceRange();
6270 Arg = Parens->getSubExpr();
6273 while (SubstNonTypeTemplateParmExpr *subst =
6274 dyn_cast<SubstNonTypeTemplateParmExpr>(Arg))
6275 Arg = subst->getReplacement()->IgnoreImpCasts();
6277 if (UnaryOperator *UnOp = dyn_cast<UnaryOperator>(Arg)) {
6278 if (UnOp->getOpcode() == UO_AddrOf) {
6279 Arg = UnOp->getSubExpr();
6280 AddressTaken = true;
6281 AddrOpLoc = UnOp->getOperatorLoc();
6285 while (SubstNonTypeTemplateParmExpr *subst =
6286 dyn_cast<SubstNonTypeTemplateParmExpr>(Arg))
6287 Arg = subst->getReplacement()->IgnoreImpCasts();
6290 DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Arg);
6291 ValueDecl *Entity = DRE ? DRE->getDecl() : nullptr;
6293 // If our parameter has pointer type, check for a null template value.
6294 if (ParamType->isPointerType() || ParamType->isNullPtrType()) {
6295 switch (isNullPointerValueTemplateArgument(S, Param, ParamType, ArgIn,
6297 case NPV_NullPointer:
6298 S.Diag(Arg->getExprLoc(), diag::warn_cxx98_compat_template_arg_null);
6299 Converted = TemplateArgument(S.Context.getCanonicalType(ParamType),
6300 /*isNullPtr=*/true);
6306 case NPV_NotNullPointer:
6311 // Stop checking the precise nature of the argument if it is value dependent,
6312 // it should be checked when instantiated.
6313 if (Arg->isValueDependent()) {
6314 Converted = TemplateArgument(ArgIn);
6318 if (isa<CXXUuidofExpr>(Arg)) {
6319 if (CheckTemplateArgumentIsCompatibleWithParameter(S, Param, ParamType,
6320 ArgIn, Arg, ArgType))
6323 Converted = TemplateArgument(ArgIn);
6328 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_not_decl_ref)
6329 << Arg->getSourceRange();
6330 S.Diag(Param->getLocation(), diag::note_template_param_here);
6334 // Cannot refer to non-static data members
6335 if (isa<FieldDecl>(Entity) || isa<IndirectFieldDecl>(Entity)) {
6336 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_field)
6337 << Entity << Arg->getSourceRange();
6338 S.Diag(Param->getLocation(), diag::note_template_param_here);
6342 // Cannot refer to non-static member functions
6343 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Entity)) {
6344 if (!Method->isStatic()) {
6345 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_method)
6346 << Method << Arg->getSourceRange();
6347 S.Diag(Param->getLocation(), diag::note_template_param_here);
6352 FunctionDecl *Func = dyn_cast<FunctionDecl>(Entity);
6353 VarDecl *Var = dyn_cast<VarDecl>(Entity);
6355 // A non-type template argument must refer to an object or function.
6356 if (!Func && !Var) {
6357 // We found something, but we don't know specifically what it is.
6358 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_not_object_or_func)
6359 << Arg->getSourceRange();
6360 S.Diag(DRE->getDecl()->getLocation(), diag::note_template_arg_refers_here);
6364 // Address / reference template args must have external linkage in C++98.
6365 if (Entity->getFormalLinkage() == InternalLinkage) {
6366 S.Diag(Arg->getBeginLoc(),
6367 S.getLangOpts().CPlusPlus11
6368 ? diag::warn_cxx98_compat_template_arg_object_internal
6369 : diag::ext_template_arg_object_internal)
6370 << !Func << Entity << Arg->getSourceRange();
6371 S.Diag(Entity->getLocation(), diag::note_template_arg_internal_object)
6373 } else if (!Entity->hasLinkage()) {
6374 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_object_no_linkage)
6375 << !Func << Entity << Arg->getSourceRange();
6376 S.Diag(Entity->getLocation(), diag::note_template_arg_internal_object)
6382 // If the template parameter has pointer type, the function decays.
6383 if (ParamType->isPointerType() && !AddressTaken)
6384 ArgType = S.Context.getPointerType(Func->getType());
6385 else if (AddressTaken && ParamType->isReferenceType()) {
6386 // If we originally had an address-of operator, but the
6387 // parameter has reference type, complain and (if things look
6388 // like they will work) drop the address-of operator.
6389 if (!S.Context.hasSameUnqualifiedType(Func->getType(),
6390 ParamType.getNonReferenceType())) {
6391 S.Diag(AddrOpLoc, diag::err_template_arg_address_of_non_pointer)
6393 S.Diag(Param->getLocation(), diag::note_template_param_here);
6397 S.Diag(AddrOpLoc, diag::err_template_arg_address_of_non_pointer)
6399 << FixItHint::CreateRemoval(AddrOpLoc);
6400 S.Diag(Param->getLocation(), diag::note_template_param_here);
6402 ArgType = Func->getType();
6405 // A value of reference type is not an object.
6406 if (Var->getType()->isReferenceType()) {
6407 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_reference_var)
6408 << Var->getType() << Arg->getSourceRange();
6409 S.Diag(Param->getLocation(), diag::note_template_param_here);
6413 // A template argument must have static storage duration.
6414 if (Var->getTLSKind()) {
6415 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_thread_local)
6416 << Arg->getSourceRange();
6417 S.Diag(Var->getLocation(), diag::note_template_arg_refers_here);
6421 // If the template parameter has pointer type, we must have taken
6422 // the address of this object.
6423 if (ParamType->isReferenceType()) {
6425 // If we originally had an address-of operator, but the
6426 // parameter has reference type, complain and (if things look
6427 // like they will work) drop the address-of operator.
6428 if (!S.Context.hasSameUnqualifiedType(Var->getType(),
6429 ParamType.getNonReferenceType())) {
6430 S.Diag(AddrOpLoc, diag::err_template_arg_address_of_non_pointer)
6432 S.Diag(Param->getLocation(), diag::note_template_param_here);
6436 S.Diag(AddrOpLoc, diag::err_template_arg_address_of_non_pointer)
6438 << FixItHint::CreateRemoval(AddrOpLoc);
6439 S.Diag(Param->getLocation(), diag::note_template_param_here);
6441 ArgType = Var->getType();
6443 } else if (!AddressTaken && ParamType->isPointerType()) {
6444 if (Var->getType()->isArrayType()) {
6445 // Array-to-pointer decay.
6446 ArgType = S.Context.getArrayDecayedType(Var->getType());
6448 // If the template parameter has pointer type but the address of
6449 // this object was not taken, complain and (possibly) recover by
6450 // taking the address of the entity.
6451 ArgType = S.Context.getPointerType(Var->getType());
6452 if (!S.Context.hasSameUnqualifiedType(ArgType, ParamType)) {
6453 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_not_address_of)
6455 S.Diag(Param->getLocation(), diag::note_template_param_here);
6459 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_not_address_of)
6460 << ParamType << FixItHint::CreateInsertion(Arg->getBeginLoc(), "&");
6462 S.Diag(Param->getLocation(), diag::note_template_param_here);
6467 if (CheckTemplateArgumentIsCompatibleWithParameter(S, Param, ParamType, ArgIn,
6471 // Create the template argument.
6473 TemplateArgument(cast<ValueDecl>(Entity->getCanonicalDecl()), ParamType);
6474 S.MarkAnyDeclReferenced(Arg->getBeginLoc(), Entity, false);
6478 /// Checks whether the given template argument is a pointer to
6479 /// member constant according to C++ [temp.arg.nontype]p1.
6480 static bool CheckTemplateArgumentPointerToMember(Sema &S,
6481 NonTypeTemplateParmDecl *Param,
6484 TemplateArgument &Converted) {
6485 bool Invalid = false;
6487 Expr *Arg = ResultArg;
6488 bool ObjCLifetimeConversion;
6490 // C++ [temp.arg.nontype]p1:
6492 // A template-argument for a non-type, non-template
6493 // template-parameter shall be one of: [...]
6495 // -- a pointer to member expressed as described in 5.3.1.
6496 DeclRefExpr *DRE = nullptr;
6498 // In C++98/03 mode, give an extension warning on any extra parentheses.
6499 // See http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#773
6500 bool ExtraParens = false;
6501 while (ParenExpr *Parens = dyn_cast<ParenExpr>(Arg)) {
6502 if (!Invalid && !ExtraParens) {
6503 S.Diag(Arg->getBeginLoc(),
6504 S.getLangOpts().CPlusPlus11
6505 ? diag::warn_cxx98_compat_template_arg_extra_parens
6506 : diag::ext_template_arg_extra_parens)
6507 << Arg->getSourceRange();
6511 Arg = Parens->getSubExpr();
6514 while (SubstNonTypeTemplateParmExpr *subst =
6515 dyn_cast<SubstNonTypeTemplateParmExpr>(Arg))
6516 Arg = subst->getReplacement()->IgnoreImpCasts();
6518 // A pointer-to-member constant written &Class::member.
6519 if (UnaryOperator *UnOp = dyn_cast<UnaryOperator>(Arg)) {
6520 if (UnOp->getOpcode() == UO_AddrOf) {
6521 DRE = dyn_cast<DeclRefExpr>(UnOp->getSubExpr());
6522 if (DRE && !DRE->getQualifier())
6526 // A constant of pointer-to-member type.
6527 else if ((DRE = dyn_cast<DeclRefExpr>(Arg))) {
6528 ValueDecl *VD = DRE->getDecl();
6529 if (VD->getType()->isMemberPointerType()) {
6530 if (isa<NonTypeTemplateParmDecl>(VD)) {
6531 if (Arg->isTypeDependent() || Arg->isValueDependent()) {
6532 Converted = TemplateArgument(Arg);
6534 VD = cast<ValueDecl>(VD->getCanonicalDecl());
6535 Converted = TemplateArgument(VD, ParamType);
6544 ValueDecl *Entity = DRE ? DRE->getDecl() : nullptr;
6546 // Check for a null pointer value.
6547 switch (isNullPointerValueTemplateArgument(S, Param, ParamType, ResultArg,
6551 case NPV_NullPointer:
6552 S.Diag(ResultArg->getExprLoc(), diag::warn_cxx98_compat_template_arg_null);
6553 Converted = TemplateArgument(S.Context.getCanonicalType(ParamType),
6556 case NPV_NotNullPointer:
6560 if (S.IsQualificationConversion(ResultArg->getType(),
6561 ParamType.getNonReferenceType(), false,
6562 ObjCLifetimeConversion)) {
6563 ResultArg = S.ImpCastExprToType(ResultArg, ParamType, CK_NoOp,
6564 ResultArg->getValueKind())
6566 } else if (!S.Context.hasSameUnqualifiedType(
6567 ResultArg->getType(), ParamType.getNonReferenceType())) {
6568 // We can't perform this conversion.
6569 S.Diag(ResultArg->getBeginLoc(), diag::err_template_arg_not_convertible)
6570 << ResultArg->getType() << ParamType << ResultArg->getSourceRange();
6571 S.Diag(Param->getLocation(), diag::note_template_param_here);
6576 return S.Diag(Arg->getBeginLoc(),
6577 diag::err_template_arg_not_pointer_to_member_form)
6578 << Arg->getSourceRange();
6580 if (isa<FieldDecl>(DRE->getDecl()) ||
6581 isa<IndirectFieldDecl>(DRE->getDecl()) ||
6582 isa<CXXMethodDecl>(DRE->getDecl())) {
6583 assert((isa<FieldDecl>(DRE->getDecl()) ||
6584 isa<IndirectFieldDecl>(DRE->getDecl()) ||
6585 !cast<CXXMethodDecl>(DRE->getDecl())->isStatic()) &&
6586 "Only non-static member pointers can make it here");
6588 // Okay: this is the address of a non-static member, and therefore
6589 // a member pointer constant.
6590 if (Arg->isTypeDependent() || Arg->isValueDependent()) {
6591 Converted = TemplateArgument(Arg);
6593 ValueDecl *D = cast<ValueDecl>(DRE->getDecl()->getCanonicalDecl());
6594 Converted = TemplateArgument(D, ParamType);
6599 // We found something else, but we don't know specifically what it is.
6600 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_not_pointer_to_member_form)
6601 << Arg->getSourceRange();
6602 S.Diag(DRE->getDecl()->getLocation(), diag::note_template_arg_refers_here);
6606 /// Check a template argument against its corresponding
6607 /// non-type template parameter.
6609 /// This routine implements the semantics of C++ [temp.arg.nontype].
6610 /// If an error occurred, it returns ExprError(); otherwise, it
6611 /// returns the converted template argument. \p ParamType is the
6612 /// type of the non-type template parameter after it has been instantiated.
6613 ExprResult Sema::CheckTemplateArgument(NonTypeTemplateParmDecl *Param,
6614 QualType ParamType, Expr *Arg,
6615 TemplateArgument &Converted,
6616 CheckTemplateArgumentKind CTAK) {
6617 SourceLocation StartLoc = Arg->getBeginLoc();
6619 // If the parameter type somehow involves auto, deduce the type now.
6620 if (getLangOpts().CPlusPlus17 && ParamType->isUndeducedType()) {
6621 // During template argument deduction, we allow 'decltype(auto)' to
6622 // match an arbitrary dependent argument.
6623 // FIXME: The language rules don't say what happens in this case.
6624 // FIXME: We get an opaque dependent type out of decltype(auto) if the
6625 // expression is merely instantiation-dependent; is this enough?
6626 if (CTAK == CTAK_Deduced && Arg->isTypeDependent()) {
6627 auto *AT = dyn_cast<AutoType>(ParamType);
6628 if (AT && AT->isDecltypeAuto()) {
6629 Converted = TemplateArgument(Arg);
6634 // When checking a deduced template argument, deduce from its type even if
6635 // the type is dependent, in order to check the types of non-type template
6636 // arguments line up properly in partial ordering.
6637 Optional<unsigned> Depth = Param->getDepth() + 1;
6638 Expr *DeductionArg = Arg;
6639 if (auto *PE = dyn_cast<PackExpansionExpr>(DeductionArg))
6640 DeductionArg = PE->getPattern();
6642 Context.getTrivialTypeSourceInfo(ParamType, Param->getLocation()),
6643 DeductionArg, ParamType, Depth,
6644 // We do not check constraints right now because the
6645 // immediately-declared constraint of the auto type is also an
6646 // associated constraint, and will be checked along with the other
6647 // associated constraints after checking the template argument list.
6648 /*IgnoreConstraints=*/true) == DAR_Failed) {
6649 Diag(Arg->getExprLoc(),
6650 diag::err_non_type_template_parm_type_deduction_failure)
6651 << Param->getDeclName() << Param->getType() << Arg->getType()
6652 << Arg->getSourceRange();
6653 Diag(Param->getLocation(), diag::note_template_param_here);
6656 // CheckNonTypeTemplateParameterType will produce a diagnostic if there's
6657 // an error. The error message normally references the parameter
6658 // declaration, but here we'll pass the argument location because that's
6659 // where the parameter type is deduced.
6660 ParamType = CheckNonTypeTemplateParameterType(ParamType, Arg->getExprLoc());
6661 if (ParamType.isNull()) {
6662 Diag(Param->getLocation(), diag::note_template_param_here);
6667 // We should have already dropped all cv-qualifiers by now.
6668 assert(!ParamType.hasQualifiers() &&
6669 "non-type template parameter type cannot be qualified");
6671 if (CTAK == CTAK_Deduced &&
6672 !Context.hasSameType(ParamType.getNonLValueExprType(Context),
6674 // FIXME: If either type is dependent, we skip the check. This isn't
6675 // correct, since during deduction we're supposed to have replaced each
6676 // template parameter with some unique (non-dependent) placeholder.
6677 // FIXME: If the argument type contains 'auto', we carry on and fail the
6678 // type check in order to force specific types to be more specialized than
6679 // 'auto'. It's not clear how partial ordering with 'auto' is supposed to
6681 if ((ParamType->isDependentType() || Arg->isTypeDependent()) &&
6682 !Arg->getType()->getContainedAutoType()) {
6683 Converted = TemplateArgument(Arg);
6686 // FIXME: This attempts to implement C++ [temp.deduct.type]p17. Per DR1770,
6687 // we should actually be checking the type of the template argument in P,
6688 // not the type of the template argument deduced from A, against the
6689 // template parameter type.
6690 Diag(StartLoc, diag::err_deduced_non_type_template_arg_type_mismatch)
6692 << ParamType.getUnqualifiedType();
6693 Diag(Param->getLocation(), diag::note_template_param_here);
6697 // If either the parameter has a dependent type or the argument is
6698 // type-dependent, there's nothing we can check now. The argument only
6699 // contains an unexpanded pack during partial ordering, and there's
6700 // nothing more we can check in that case.
6701 if (ParamType->isDependentType() || Arg->isTypeDependent() ||
6702 Arg->containsUnexpandedParameterPack()) {
6703 // Force the argument to the type of the parameter to maintain invariants.
6704 auto *PE = dyn_cast<PackExpansionExpr>(Arg);
6706 Arg = PE->getPattern();
6707 ExprResult E = ImpCastExprToType(
6708 Arg, ParamType.getNonLValueExprType(Context), CK_Dependent,
6709 ParamType->isLValueReferenceType() ? VK_LValue :
6710 ParamType->isRValueReferenceType() ? VK_XValue : VK_RValue);
6714 // Recreate a pack expansion if we unwrapped one.
6716 PackExpansionExpr(E.get()->getType(), E.get(), PE->getEllipsisLoc(),
6717 PE->getNumExpansions());
6719 Converted = TemplateArgument(E.get());
6723 // The initialization of the parameter from the argument is
6724 // a constant-evaluated context.
6725 EnterExpressionEvaluationContext ConstantEvaluated(
6726 *this, Sema::ExpressionEvaluationContext::ConstantEvaluated);
6728 if (getLangOpts().CPlusPlus17) {
6729 // C++17 [temp.arg.nontype]p1:
6730 // A template-argument for a non-type template parameter shall be
6731 // a converted constant expression of the type of the template-parameter.
6733 ExprResult ArgResult = CheckConvertedConstantExpression(
6734 Arg, ParamType, Value, CCEK_TemplateArg);
6735 if (ArgResult.isInvalid())
6738 // For a value-dependent argument, CheckConvertedConstantExpression is
6739 // permitted (and expected) to be unable to determine a value.
6740 if (ArgResult.get()->isValueDependent()) {
6741 Converted = TemplateArgument(ArgResult.get());
6745 QualType CanonParamType = Context.getCanonicalType(ParamType);
6747 // Convert the APValue to a TemplateArgument.
6748 switch (Value.getKind()) {
6750 assert(ParamType->isNullPtrType());
6751 Converted = TemplateArgument(CanonParamType, /*isNullPtr*/true);
6753 case APValue::Indeterminate:
6754 llvm_unreachable("result of constant evaluation should be initialized");
6757 assert(ParamType->isIntegralOrEnumerationType());
6758 Converted = TemplateArgument(Context, Value.getInt(), CanonParamType);
6760 case APValue::MemberPointer: {
6761 assert(ParamType->isMemberPointerType());
6763 // FIXME: We need TemplateArgument representation and mangling for these.
6764 if (!Value.getMemberPointerPath().empty()) {
6765 Diag(Arg->getBeginLoc(),
6766 diag::err_template_arg_member_ptr_base_derived_not_supported)
6767 << Value.getMemberPointerDecl() << ParamType
6768 << Arg->getSourceRange();
6772 auto *VD = const_cast<ValueDecl*>(Value.getMemberPointerDecl());
6773 Converted = VD ? TemplateArgument(VD, CanonParamType)
6774 : TemplateArgument(CanonParamType, /*isNullPtr*/true);
6777 case APValue::LValue: {
6778 // For a non-type template-parameter of pointer or reference type,
6779 // the value of the constant expression shall not refer to
6780 assert(ParamType->isPointerType() || ParamType->isReferenceType() ||
6781 ParamType->isNullPtrType());
6782 // -- a temporary object
6783 // -- a string literal
6784 // -- the result of a typeid expression, or
6785 // -- a predefined __func__ variable
6786 APValue::LValueBase Base = Value.getLValueBase();
6787 auto *VD = const_cast<ValueDecl *>(Base.dyn_cast<const ValueDecl *>());
6789 auto *E = Base.dyn_cast<const Expr *>();
6790 if (E && isa<CXXUuidofExpr>(E)) {
6791 Converted = TemplateArgument(ArgResult.get()->IgnoreImpCasts());
6794 Diag(Arg->getBeginLoc(), diag::err_template_arg_not_decl_ref)
6795 << Arg->getSourceRange();
6799 if (Value.hasLValuePath() && Value.getLValuePath().size() == 1 &&
6800 VD && VD->getType()->isArrayType() &&
6801 Value.getLValuePath()[0].getAsArrayIndex() == 0 &&
6802 !Value.isLValueOnePastTheEnd() && ParamType->isPointerType()) {
6803 // Per defect report (no number yet):
6804 // ... other than a pointer to the first element of a complete array
6806 } else if (!Value.hasLValuePath() || Value.getLValuePath().size() ||
6807 Value.isLValueOnePastTheEnd()) {
6808 Diag(StartLoc, diag::err_non_type_template_arg_subobject)
6809 << Value.getAsString(Context, ParamType);
6812 assert((VD || !ParamType->isReferenceType()) &&
6813 "null reference should not be a constant expression");
6814 assert((!VD || !ParamType->isNullPtrType()) &&
6815 "non-null value of type nullptr_t?");
6816 Converted = VD ? TemplateArgument(VD, CanonParamType)
6817 : TemplateArgument(CanonParamType, /*isNullPtr*/true);
6820 case APValue::AddrLabelDiff:
6821 return Diag(StartLoc, diag::err_non_type_template_arg_addr_label_diff);
6822 case APValue::FixedPoint:
6823 case APValue::Float:
6824 case APValue::ComplexInt:
6825 case APValue::ComplexFloat:
6826 case APValue::Vector:
6827 case APValue::Array:
6828 case APValue::Struct:
6829 case APValue::Union:
6830 llvm_unreachable("invalid kind for template argument");
6833 return ArgResult.get();
6836 // C++ [temp.arg.nontype]p5:
6837 // The following conversions are performed on each expression used
6838 // as a non-type template-argument. If a non-type
6839 // template-argument cannot be converted to the type of the
6840 // corresponding template-parameter then the program is
6842 if (ParamType->isIntegralOrEnumerationType()) {
6844 // -- for a non-type template-parameter of integral or
6845 // enumeration type, conversions permitted in a converted
6846 // constant expression are applied.
6849 // -- for a non-type template-parameter of integral or
6850 // enumeration type, integral promotions (4.5) and integral
6851 // conversions (4.7) are applied.
6853 if (getLangOpts().CPlusPlus11) {
6854 // C++ [temp.arg.nontype]p1:
6855 // A template-argument for a non-type, non-template template-parameter
6858 // -- for a non-type template-parameter of integral or enumeration
6859 // type, a converted constant expression of the type of the
6860 // template-parameter; or
6862 ExprResult ArgResult =
6863 CheckConvertedConstantExpression(Arg, ParamType, Value,
6865 if (ArgResult.isInvalid())
6868 // We can't check arbitrary value-dependent arguments.
6869 if (ArgResult.get()->isValueDependent()) {
6870 Converted = TemplateArgument(ArgResult.get());
6874 // Widen the argument value to sizeof(parameter type). This is almost
6875 // always a no-op, except when the parameter type is bool. In
6876 // that case, this may extend the argument from 1 bit to 8 bits.
6877 QualType IntegerType = ParamType;
6878 if (const EnumType *Enum = IntegerType->getAs<EnumType>())
6879 IntegerType = Enum->getDecl()->getIntegerType();
6880 Value = Value.extOrTrunc(Context.getTypeSize(IntegerType));
6882 Converted = TemplateArgument(Context, Value,
6883 Context.getCanonicalType(ParamType));
6887 ExprResult ArgResult = DefaultLvalueConversion(Arg);
6888 if (ArgResult.isInvalid())
6890 Arg = ArgResult.get();
6892 QualType ArgType = Arg->getType();
6894 // C++ [temp.arg.nontype]p1:
6895 // A template-argument for a non-type, non-template
6896 // template-parameter shall be one of:
6898 // -- an integral constant-expression of integral or enumeration
6900 // -- the name of a non-type template-parameter; or
6902 if (!ArgType->isIntegralOrEnumerationType()) {
6903 Diag(Arg->getBeginLoc(), diag::err_template_arg_not_integral_or_enumeral)
6904 << ArgType << Arg->getSourceRange();
6905 Diag(Param->getLocation(), diag::note_template_param_here);
6907 } else if (!Arg->isValueDependent()) {
6908 class TmplArgICEDiagnoser : public VerifyICEDiagnoser {
6912 TmplArgICEDiagnoser(QualType T) : T(T) { }
6914 void diagnoseNotICE(Sema &S, SourceLocation Loc,
6915 SourceRange SR) override {
6916 S.Diag(Loc, diag::err_template_arg_not_ice) << T << SR;
6918 } Diagnoser(ArgType);
6920 Arg = VerifyIntegerConstantExpression(Arg, &Value, Diagnoser,
6926 // From here on out, all we care about is the unqualified form
6927 // of the argument type.
6928 ArgType = ArgType.getUnqualifiedType();
6930 // Try to convert the argument to the parameter's type.
6931 if (Context.hasSameType(ParamType, ArgType)) {
6932 // Okay: no conversion necessary
6933 } else if (ParamType->isBooleanType()) {
6934 // This is an integral-to-boolean conversion.
6935 Arg = ImpCastExprToType(Arg, ParamType, CK_IntegralToBoolean).get();
6936 } else if (IsIntegralPromotion(Arg, ArgType, ParamType) ||
6937 !ParamType->isEnumeralType()) {
6938 // This is an integral promotion or conversion.
6939 Arg = ImpCastExprToType(Arg, ParamType, CK_IntegralCast).get();
6941 // We can't perform this conversion.
6942 Diag(Arg->getBeginLoc(), diag::err_template_arg_not_convertible)
6943 << Arg->getType() << ParamType << Arg->getSourceRange();
6944 Diag(Param->getLocation(), diag::note_template_param_here);
6948 // Add the value of this argument to the list of converted
6949 // arguments. We use the bitwidth and signedness of the template
6951 if (Arg->isValueDependent()) {
6952 // The argument is value-dependent. Create a new
6953 // TemplateArgument with the converted expression.
6954 Converted = TemplateArgument(Arg);
6958 QualType IntegerType = Context.getCanonicalType(ParamType);
6959 if (const EnumType *Enum = IntegerType->getAs<EnumType>())
6960 IntegerType = Context.getCanonicalType(Enum->getDecl()->getIntegerType());
6962 if (ParamType->isBooleanType()) {
6963 // Value must be zero or one.
6965 unsigned AllowedBits = Context.getTypeSize(IntegerType);
6966 if (Value.getBitWidth() != AllowedBits)
6967 Value = Value.extOrTrunc(AllowedBits);
6968 Value.setIsSigned(IntegerType->isSignedIntegerOrEnumerationType());
6970 llvm::APSInt OldValue = Value;
6972 // Coerce the template argument's value to the value it will have
6973 // based on the template parameter's type.
6974 unsigned AllowedBits = Context.getTypeSize(IntegerType);
6975 if (Value.getBitWidth() != AllowedBits)
6976 Value = Value.extOrTrunc(AllowedBits);
6977 Value.setIsSigned(IntegerType->isSignedIntegerOrEnumerationType());
6979 // Complain if an unsigned parameter received a negative value.
6980 if (IntegerType->isUnsignedIntegerOrEnumerationType()
6981 && (OldValue.isSigned() && OldValue.isNegative())) {
6982 Diag(Arg->getBeginLoc(), diag::warn_template_arg_negative)
6983 << OldValue.toString(10) << Value.toString(10) << Param->getType()
6984 << Arg->getSourceRange();
6985 Diag(Param->getLocation(), diag::note_template_param_here);
6988 // Complain if we overflowed the template parameter's type.
6989 unsigned RequiredBits;
6990 if (IntegerType->isUnsignedIntegerOrEnumerationType())
6991 RequiredBits = OldValue.getActiveBits();
6992 else if (OldValue.isUnsigned())
6993 RequiredBits = OldValue.getActiveBits() + 1;
6995 RequiredBits = OldValue.getMinSignedBits();
6996 if (RequiredBits > AllowedBits) {
6997 Diag(Arg->getBeginLoc(), diag::warn_template_arg_too_large)
6998 << OldValue.toString(10) << Value.toString(10) << Param->getType()
6999 << Arg->getSourceRange();
7000 Diag(Param->getLocation(), diag::note_template_param_here);
7004 Converted = TemplateArgument(Context, Value,
7005 ParamType->isEnumeralType()
7006 ? Context.getCanonicalType(ParamType)
7011 QualType ArgType = Arg->getType();
7012 DeclAccessPair FoundResult; // temporary for ResolveOverloadedFunction
7014 // Handle pointer-to-function, reference-to-function, and
7015 // pointer-to-member-function all in (roughly) the same way.
7016 if (// -- For a non-type template-parameter of type pointer to
7017 // function, only the function-to-pointer conversion (4.3) is
7018 // applied. If the template-argument represents a set of
7019 // overloaded functions (or a pointer to such), the matching
7020 // function is selected from the set (13.4).
7021 (ParamType->isPointerType() &&
7022 ParamType->castAs<PointerType>()->getPointeeType()->isFunctionType()) ||
7023 // -- For a non-type template-parameter of type reference to
7024 // function, no conversions apply. If the template-argument
7025 // represents a set of overloaded functions, the matching
7026 // function is selected from the set (13.4).
7027 (ParamType->isReferenceType() &&
7028 ParamType->castAs<ReferenceType>()->getPointeeType()->isFunctionType()) ||
7029 // -- For a non-type template-parameter of type pointer to
7030 // member function, no conversions apply. If the
7031 // template-argument represents a set of overloaded member
7032 // functions, the matching member function is selected from
7034 (ParamType->isMemberPointerType() &&
7035 ParamType->castAs<MemberPointerType>()->getPointeeType()
7036 ->isFunctionType())) {
7038 if (Arg->getType() == Context.OverloadTy) {
7039 if (FunctionDecl *Fn = ResolveAddressOfOverloadedFunction(Arg, ParamType,
7042 if (DiagnoseUseOfDecl(Fn, Arg->getBeginLoc()))
7045 Arg = FixOverloadedFunctionReference(Arg, FoundResult, Fn);
7046 ArgType = Arg->getType();
7051 if (!ParamType->isMemberPointerType()) {
7052 if (CheckTemplateArgumentAddressOfObjectOrFunction(*this, Param,
7059 if (CheckTemplateArgumentPointerToMember(*this, Param, ParamType, Arg,
7065 if (ParamType->isPointerType()) {
7066 // -- for a non-type template-parameter of type pointer to
7067 // object, qualification conversions (4.4) and the
7068 // array-to-pointer conversion (4.2) are applied.
7069 // C++0x also allows a value of std::nullptr_t.
7070 assert(ParamType->getPointeeType()->isIncompleteOrObjectType() &&
7071 "Only object pointers allowed here");
7073 if (CheckTemplateArgumentAddressOfObjectOrFunction(*this, Param,
7080 if (const ReferenceType *ParamRefType = ParamType->getAs<ReferenceType>()) {
7081 // -- For a non-type template-parameter of type reference to
7082 // object, no conversions apply. The type referred to by the
7083 // reference may be more cv-qualified than the (otherwise
7084 // identical) type of the template-argument. The
7085 // template-parameter is bound directly to the
7086 // template-argument, which must be an lvalue.
7087 assert(ParamRefType->getPointeeType()->isIncompleteOrObjectType() &&
7088 "Only object references allowed here");
7090 if (Arg->getType() == Context.OverloadTy) {
7091 if (FunctionDecl *Fn = ResolveAddressOfOverloadedFunction(Arg,
7092 ParamRefType->getPointeeType(),
7095 if (DiagnoseUseOfDecl(Fn, Arg->getBeginLoc()))
7098 Arg = FixOverloadedFunctionReference(Arg, FoundResult, Fn);
7099 ArgType = Arg->getType();
7104 if (CheckTemplateArgumentAddressOfObjectOrFunction(*this, Param,
7111 // Deal with parameters of type std::nullptr_t.
7112 if (ParamType->isNullPtrType()) {
7113 if (Arg->isTypeDependent() || Arg->isValueDependent()) {
7114 Converted = TemplateArgument(Arg);
7118 switch (isNullPointerValueTemplateArgument(*this, Param, ParamType, Arg)) {
7119 case NPV_NotNullPointer:
7120 Diag(Arg->getExprLoc(), diag::err_template_arg_not_convertible)
7121 << Arg->getType() << ParamType;
7122 Diag(Param->getLocation(), diag::note_template_param_here);
7128 case NPV_NullPointer:
7129 Diag(Arg->getExprLoc(), diag::warn_cxx98_compat_template_arg_null);
7130 Converted = TemplateArgument(Context.getCanonicalType(ParamType),
7136 // -- For a non-type template-parameter of type pointer to data
7137 // member, qualification conversions (4.4) are applied.
7138 assert(ParamType->isMemberPointerType() && "Only pointers to members remain");
7140 if (CheckTemplateArgumentPointerToMember(*this, Param, ParamType, Arg,
7146 static void DiagnoseTemplateParameterListArityMismatch(
7147 Sema &S, TemplateParameterList *New, TemplateParameterList *Old,
7148 Sema::TemplateParameterListEqualKind Kind, SourceLocation TemplateArgLoc);
7150 /// Check a template argument against its corresponding
7151 /// template template parameter.
7153 /// This routine implements the semantics of C++ [temp.arg.template].
7154 /// It returns true if an error occurred, and false otherwise.
7155 bool Sema::CheckTemplateTemplateArgument(TemplateTemplateParmDecl *Param,
7156 TemplateParameterList *Params,
7157 TemplateArgumentLoc &Arg) {
7158 TemplateName Name = Arg.getArgument().getAsTemplateOrTemplatePattern();
7159 TemplateDecl *Template = Name.getAsTemplateDecl();
7161 // Any dependent template name is fine.
7162 assert(Name.isDependent() && "Non-dependent template isn't a declaration?");
7166 if (Template->isInvalidDecl())
7169 // C++0x [temp.arg.template]p1:
7170 // A template-argument for a template template-parameter shall be
7171 // the name of a class template or an alias template, expressed as an
7172 // id-expression. When the template-argument names a class template, only
7173 // primary class templates are considered when matching the
7174 // template template argument with the corresponding parameter;
7175 // partial specializations are not considered even if their
7176 // parameter lists match that of the template template parameter.
7178 // Note that we also allow template template parameters here, which
7179 // will happen when we are dealing with, e.g., class template
7180 // partial specializations.
7181 if (!isa<ClassTemplateDecl>(Template) &&
7182 !isa<TemplateTemplateParmDecl>(Template) &&
7183 !isa<TypeAliasTemplateDecl>(Template) &&
7184 !isa<BuiltinTemplateDecl>(Template)) {
7185 assert(isa<FunctionTemplateDecl>(Template) &&
7186 "Only function templates are possible here");
7187 Diag(Arg.getLocation(), diag::err_template_arg_not_valid_template);
7188 Diag(Template->getLocation(), diag::note_template_arg_refers_here_func)
7192 // C++1z [temp.arg.template]p3: (DR 150)
7193 // A template-argument matches a template template-parameter P when P
7194 // is at least as specialized as the template-argument A.
7195 // FIXME: We should enable RelaxedTemplateTemplateArgs by default as it is a
7196 // defect report resolution from C++17 and shouldn't be introduced by
7198 if (getLangOpts().RelaxedTemplateTemplateArgs) {
7199 // Quick check for the common case:
7200 // If P contains a parameter pack, then A [...] matches P if each of A's
7201 // template parameters matches the corresponding template parameter in
7202 // the template-parameter-list of P.
7203 if (TemplateParameterListsAreEqual(
7204 Template->getTemplateParameters(), Params, false,
7205 TPL_TemplateTemplateArgumentMatch, Arg.getLocation()) &&
7206 // If the argument has no associated constraints, then the parameter is
7207 // definitely at least as specialized as the argument.
7208 // Otherwise - we need a more thorough check.
7209 !Template->hasAssociatedConstraints())
7212 if (isTemplateTemplateParameterAtLeastAsSpecializedAs(Params, Template,
7213 Arg.getLocation())) {
7214 // C++2a[temp.func.order]p2
7215 // [...] If both deductions succeed, the partial ordering selects the
7216 // more constrained template as described by the rules in
7217 // [temp.constr.order].
7218 SmallVector<const Expr *, 3> ParamsAC, TemplateAC;
7219 Params->getAssociatedConstraints(ParamsAC);
7220 // C++2a[temp.arg.template]p3
7221 // [...] In this comparison, if P is unconstrained, the constraints on A
7222 // are not considered.
7223 if (ParamsAC.empty())
7225 Template->getAssociatedConstraints(TemplateAC);
7226 bool IsParamAtLeastAsConstrained;
7227 if (IsAtLeastAsConstrained(Param, ParamsAC, Template, TemplateAC,
7228 IsParamAtLeastAsConstrained))
7230 if (!IsParamAtLeastAsConstrained) {
7231 Diag(Arg.getLocation(),
7232 diag::err_template_template_parameter_not_at_least_as_constrained)
7233 << Template << Param << Arg.getSourceRange();
7234 Diag(Param->getLocation(), diag::note_entity_declared_at) << Param;
7235 Diag(Template->getLocation(), diag::note_entity_declared_at)
7237 MaybeEmitAmbiguousAtomicConstraintsDiagnostic(Param, ParamsAC, Template,
7243 // FIXME: Produce better diagnostics for deduction failures.
7246 return !TemplateParameterListsAreEqual(Template->getTemplateParameters(),
7249 TPL_TemplateTemplateArgumentMatch,
7253 /// Given a non-type template argument that refers to a
7254 /// declaration and the type of its corresponding non-type template
7255 /// parameter, produce an expression that properly refers to that
7258 Sema::BuildExpressionFromDeclTemplateArgument(const TemplateArgument &Arg,
7260 SourceLocation Loc) {
7261 // C++ [temp.param]p8:
7263 // A non-type template-parameter of type "array of T" or
7264 // "function returning T" is adjusted to be of type "pointer to
7265 // T" or "pointer to function returning T", respectively.
7266 if (ParamType->isArrayType())
7267 ParamType = Context.getArrayDecayedType(ParamType);
7268 else if (ParamType->isFunctionType())
7269 ParamType = Context.getPointerType(ParamType);
7271 // For a NULL non-type template argument, return nullptr casted to the
7272 // parameter's type.
7273 if (Arg.getKind() == TemplateArgument::NullPtr) {
7274 return ImpCastExprToType(
7275 new (Context) CXXNullPtrLiteralExpr(Context.NullPtrTy, Loc),
7277 ParamType->getAs<MemberPointerType>()
7278 ? CK_NullToMemberPointer
7279 : CK_NullToPointer);
7281 assert(Arg.getKind() == TemplateArgument::Declaration &&
7282 "Only declaration template arguments permitted here");
7284 ValueDecl *VD = Arg.getAsDecl();
7287 if (ParamType->isMemberPointerType()) {
7288 // If this is a pointer to member, we need to use a qualified name to
7289 // form a suitable pointer-to-member constant.
7290 assert(VD->getDeclContext()->isRecord() &&
7291 (isa<CXXMethodDecl>(VD) || isa<FieldDecl>(VD) ||
7292 isa<IndirectFieldDecl>(VD)));
7294 = Context.getTypeDeclType(cast<RecordDecl>(VD->getDeclContext()));
7295 NestedNameSpecifier *Qualifier
7296 = NestedNameSpecifier::Create(Context, nullptr, false,
7297 ClassType.getTypePtr());
7298 SS.MakeTrivial(Context, Qualifier, Loc);
7301 ExprResult RefExpr = BuildDeclarationNameExpr(
7302 SS, DeclarationNameInfo(VD->getDeclName(), Loc), VD);
7303 if (RefExpr.isInvalid())
7306 // For a pointer, the argument declaration is the pointee. Take its address.
7307 QualType ElemT(RefExpr.get()->getType()->getArrayElementTypeNoTypeQual(), 0);
7308 if (ParamType->isPointerType() && !ElemT.isNull() &&
7309 Context.hasSimilarType(ElemT, ParamType->getPointeeType())) {
7310 // Decay an array argument if we want a pointer to its first element.
7311 RefExpr = DefaultFunctionArrayConversion(RefExpr.get());
7312 if (RefExpr.isInvalid())
7314 } else if (ParamType->isPointerType() || ParamType->isMemberPointerType()) {
7315 // For any other pointer, take the address (or form a pointer-to-member).
7316 RefExpr = CreateBuiltinUnaryOp(Loc, UO_AddrOf, RefExpr.get());
7317 if (RefExpr.isInvalid())
7320 assert(ParamType->isReferenceType() &&
7321 "unexpected type for decl template argument");
7324 // At this point we should have the right value category.
7325 assert(ParamType->isReferenceType() == RefExpr.get()->isLValue() &&
7326 "value kind mismatch for non-type template argument");
7328 // The type of the template parameter can differ from the type of the
7329 // argument in various ways; convert it now if necessary.
7330 QualType DestExprType = ParamType.getNonLValueExprType(Context);
7331 if (!Context.hasSameType(RefExpr.get()->getType(), DestExprType)) {
7334 if (Context.hasSimilarType(RefExpr.get()->getType(), DestExprType) ||
7335 IsFunctionConversion(RefExpr.get()->getType(), DestExprType, Ignored)) {
7337 } else if (ParamType->isVoidPointerType() &&
7338 RefExpr.get()->getType()->isPointerType()) {
7341 // FIXME: Pointers to members can need conversion derived-to-base or
7342 // base-to-derived conversions. We currently don't retain enough
7343 // information to convert properly (we need to track a cast path or
7344 // subobject number in the template argument).
7346 "unexpected conversion required for non-type template argument");
7348 RefExpr = ImpCastExprToType(RefExpr.get(), DestExprType, CK,
7349 RefExpr.get()->getValueKind());
7355 /// Construct a new expression that refers to the given
7356 /// integral template argument with the given source-location
7359 /// This routine takes care of the mapping from an integral template
7360 /// argument (which may have any integral type) to the appropriate
7363 Sema::BuildExpressionFromIntegralTemplateArgument(const TemplateArgument &Arg,
7364 SourceLocation Loc) {
7365 assert(Arg.getKind() == TemplateArgument::Integral &&
7366 "Operation is only valid for integral template arguments");
7367 QualType OrigT = Arg.getIntegralType();
7369 // If this is an enum type that we're instantiating, we need to use an integer
7370 // type the same size as the enumerator. We don't want to build an
7371 // IntegerLiteral with enum type. The integer type of an enum type can be of
7372 // any integral type with C++11 enum classes, make sure we create the right
7373 // type of literal for it.
7375 if (const EnumType *ET = OrigT->getAs<EnumType>())
7376 T = ET->getDecl()->getIntegerType();
7379 if (T->isAnyCharacterType()) {
7380 CharacterLiteral::CharacterKind Kind;
7381 if (T->isWideCharType())
7382 Kind = CharacterLiteral::Wide;
7383 else if (T->isChar8Type() && getLangOpts().Char8)
7384 Kind = CharacterLiteral::UTF8;
7385 else if (T->isChar16Type())
7386 Kind = CharacterLiteral::UTF16;
7387 else if (T->isChar32Type())
7388 Kind = CharacterLiteral::UTF32;
7390 Kind = CharacterLiteral::Ascii;
7392 E = new (Context) CharacterLiteral(Arg.getAsIntegral().getZExtValue(),
7394 } else if (T->isBooleanType()) {
7395 E = new (Context) CXXBoolLiteralExpr(Arg.getAsIntegral().getBoolValue(),
7397 } else if (T->isNullPtrType()) {
7398 E = new (Context) CXXNullPtrLiteralExpr(Context.NullPtrTy, Loc);
7400 E = IntegerLiteral::Create(Context, Arg.getAsIntegral(), T, Loc);
7403 if (OrigT->isEnumeralType()) {
7404 // FIXME: This is a hack. We need a better way to handle substituted
7405 // non-type template parameters.
7406 E = CStyleCastExpr::Create(Context, OrigT, VK_RValue, CK_IntegralCast, E,
7408 Context.getTrivialTypeSourceInfo(OrigT, Loc),
7415 /// Match two template parameters within template parameter lists.
7416 static bool MatchTemplateParameterKind(Sema &S, NamedDecl *New, NamedDecl *Old,
7418 Sema::TemplateParameterListEqualKind Kind,
7419 SourceLocation TemplateArgLoc) {
7420 // Check the actual kind (type, non-type, template).
7421 if (Old->getKind() != New->getKind()) {
7423 unsigned NextDiag = diag::err_template_param_different_kind;
7424 if (TemplateArgLoc.isValid()) {
7425 S.Diag(TemplateArgLoc, diag::err_template_arg_template_params_mismatch);
7426 NextDiag = diag::note_template_param_different_kind;
7428 S.Diag(New->getLocation(), NextDiag)
7429 << (Kind != Sema::TPL_TemplateMatch);
7430 S.Diag(Old->getLocation(), diag::note_template_prev_declaration)
7431 << (Kind != Sema::TPL_TemplateMatch);
7437 // Check that both are parameter packs or neither are parameter packs.
7438 // However, if we are matching a template template argument to a
7439 // template template parameter, the template template parameter can have
7440 // a parameter pack where the template template argument does not.
7441 if (Old->isTemplateParameterPack() != New->isTemplateParameterPack() &&
7442 !(Kind == Sema::TPL_TemplateTemplateArgumentMatch &&
7443 Old->isTemplateParameterPack())) {
7445 unsigned NextDiag = diag::err_template_parameter_pack_non_pack;
7446 if (TemplateArgLoc.isValid()) {
7447 S.Diag(TemplateArgLoc,
7448 diag::err_template_arg_template_params_mismatch);
7449 NextDiag = diag::note_template_parameter_pack_non_pack;
7452 unsigned ParamKind = isa<TemplateTypeParmDecl>(New)? 0
7453 : isa<NonTypeTemplateParmDecl>(New)? 1
7455 S.Diag(New->getLocation(), NextDiag)
7456 << ParamKind << New->isParameterPack();
7457 S.Diag(Old->getLocation(), diag::note_template_parameter_pack_here)
7458 << ParamKind << Old->isParameterPack();
7464 // For non-type template parameters, check the type of the parameter.
7465 if (NonTypeTemplateParmDecl *OldNTTP
7466 = dyn_cast<NonTypeTemplateParmDecl>(Old)) {
7467 NonTypeTemplateParmDecl *NewNTTP = cast<NonTypeTemplateParmDecl>(New);
7469 // If we are matching a template template argument to a template
7470 // template parameter and one of the non-type template parameter types
7471 // is dependent, then we must wait until template instantiation time
7472 // to actually compare the arguments.
7473 if (Kind != Sema::TPL_TemplateTemplateArgumentMatch ||
7474 (!OldNTTP->getType()->isDependentType() &&
7475 !NewNTTP->getType()->isDependentType()))
7476 if (!S.Context.hasSameType(OldNTTP->getType(), NewNTTP->getType())) {
7478 unsigned NextDiag = diag::err_template_nontype_parm_different_type;
7479 if (TemplateArgLoc.isValid()) {
7480 S.Diag(TemplateArgLoc,
7481 diag::err_template_arg_template_params_mismatch);
7482 NextDiag = diag::note_template_nontype_parm_different_type;
7484 S.Diag(NewNTTP->getLocation(), NextDiag)
7485 << NewNTTP->getType()
7486 << (Kind != Sema::TPL_TemplateMatch);
7487 S.Diag(OldNTTP->getLocation(),
7488 diag::note_template_nontype_parm_prev_declaration)
7489 << OldNTTP->getType();
7495 // For template template parameters, check the template parameter types.
7496 // The template parameter lists of template template
7497 // parameters must agree.
7498 else if (TemplateTemplateParmDecl *OldTTP
7499 = dyn_cast<TemplateTemplateParmDecl>(Old)) {
7500 TemplateTemplateParmDecl *NewTTP = cast<TemplateTemplateParmDecl>(New);
7501 if (!S.TemplateParameterListsAreEqual(NewTTP->getTemplateParameters(),
7502 OldTTP->getTemplateParameters(),
7504 (Kind == Sema::TPL_TemplateMatch
7505 ? Sema::TPL_TemplateTemplateParmMatch
7509 } else if (Kind != Sema::TPL_TemplateTemplateArgumentMatch) {
7510 const Expr *NewC = nullptr, *OldC = nullptr;
7511 if (const auto *TC = cast<TemplateTypeParmDecl>(New)->getTypeConstraint())
7512 NewC = TC->getImmediatelyDeclaredConstraint();
7513 if (const auto *TC = cast<TemplateTypeParmDecl>(Old)->getTypeConstraint())
7514 OldC = TC->getImmediatelyDeclaredConstraint();
7516 auto Diagnose = [&] {
7517 S.Diag(NewC ? NewC->getBeginLoc() : New->getBeginLoc(),
7518 diag::err_template_different_type_constraint);
7519 S.Diag(OldC ? OldC->getBeginLoc() : Old->getBeginLoc(),
7520 diag::note_template_prev_declaration) << /*declaration*/0;
7523 if (!NewC != !OldC) {
7530 llvm::FoldingSetNodeID OldCID, NewCID;
7531 OldC->Profile(OldCID, S.Context, /*Canonical=*/true);
7532 NewC->Profile(NewCID, S.Context, /*Canonical=*/true);
7533 if (OldCID != NewCID) {
7544 /// Diagnose a known arity mismatch when comparing template argument
7547 void DiagnoseTemplateParameterListArityMismatch(Sema &S,
7548 TemplateParameterList *New,
7549 TemplateParameterList *Old,
7550 Sema::TemplateParameterListEqualKind Kind,
7551 SourceLocation TemplateArgLoc) {
7552 unsigned NextDiag = diag::err_template_param_list_different_arity;
7553 if (TemplateArgLoc.isValid()) {
7554 S.Diag(TemplateArgLoc, diag::err_template_arg_template_params_mismatch);
7555 NextDiag = diag::note_template_param_list_different_arity;
7557 S.Diag(New->getTemplateLoc(), NextDiag)
7558 << (New->size() > Old->size())
7559 << (Kind != Sema::TPL_TemplateMatch)
7560 << SourceRange(New->getTemplateLoc(), New->getRAngleLoc());
7561 S.Diag(Old->getTemplateLoc(), diag::note_template_prev_declaration)
7562 << (Kind != Sema::TPL_TemplateMatch)
7563 << SourceRange(Old->getTemplateLoc(), Old->getRAngleLoc());
7566 /// Determine whether the given template parameter lists are
7569 /// \param New The new template parameter list, typically written in the
7570 /// source code as part of a new template declaration.
7572 /// \param Old The old template parameter list, typically found via
7573 /// name lookup of the template declared with this template parameter
7576 /// \param Complain If true, this routine will produce a diagnostic if
7577 /// the template parameter lists are not equivalent.
7579 /// \param Kind describes how we are to match the template parameter lists.
7581 /// \param TemplateArgLoc If this source location is valid, then we
7582 /// are actually checking the template parameter list of a template
7583 /// argument (New) against the template parameter list of its
7584 /// corresponding template template parameter (Old). We produce
7585 /// slightly different diagnostics in this scenario.
7587 /// \returns True if the template parameter lists are equal, false
7590 Sema::TemplateParameterListsAreEqual(TemplateParameterList *New,
7591 TemplateParameterList *Old,
7593 TemplateParameterListEqualKind Kind,
7594 SourceLocation TemplateArgLoc) {
7595 if (Old->size() != New->size() && Kind != TPL_TemplateTemplateArgumentMatch) {
7597 DiagnoseTemplateParameterListArityMismatch(*this, New, Old, Kind,
7603 // C++0x [temp.arg.template]p3:
7604 // A template-argument matches a template template-parameter (call it P)
7605 // when each of the template parameters in the template-parameter-list of
7606 // the template-argument's corresponding class template or alias template
7607 // (call it A) matches the corresponding template parameter in the
7608 // template-parameter-list of P. [...]
7609 TemplateParameterList::iterator NewParm = New->begin();
7610 TemplateParameterList::iterator NewParmEnd = New->end();
7611 for (TemplateParameterList::iterator OldParm = Old->begin(),
7612 OldParmEnd = Old->end();
7613 OldParm != OldParmEnd; ++OldParm) {
7614 if (Kind != TPL_TemplateTemplateArgumentMatch ||
7615 !(*OldParm)->isTemplateParameterPack()) {
7616 if (NewParm == NewParmEnd) {
7618 DiagnoseTemplateParameterListArityMismatch(*this, New, Old, Kind,
7624 if (!MatchTemplateParameterKind(*this, *NewParm, *OldParm, Complain,
7625 Kind, TemplateArgLoc))
7632 // C++0x [temp.arg.template]p3:
7633 // [...] When P's template- parameter-list contains a template parameter
7634 // pack (14.5.3), the template parameter pack will match zero or more
7635 // template parameters or template parameter packs in the
7636 // template-parameter-list of A with the same type and form as the
7637 // template parameter pack in P (ignoring whether those template
7638 // parameters are template parameter packs).
7639 for (; NewParm != NewParmEnd; ++NewParm) {
7640 if (!MatchTemplateParameterKind(*this, *NewParm, *OldParm, Complain,
7641 Kind, TemplateArgLoc))
7646 // Make sure we exhausted all of the arguments.
7647 if (NewParm != NewParmEnd) {
7649 DiagnoseTemplateParameterListArityMismatch(*this, New, Old, Kind,
7655 if (Kind != TPL_TemplateTemplateArgumentMatch) {
7656 const Expr *NewRC = New->getRequiresClause();
7657 const Expr *OldRC = Old->getRequiresClause();
7659 auto Diagnose = [&] {
7660 Diag(NewRC ? NewRC->getBeginLoc() : New->getTemplateLoc(),
7661 diag::err_template_different_requires_clause);
7662 Diag(OldRC ? OldRC->getBeginLoc() : Old->getTemplateLoc(),
7663 diag::note_template_prev_declaration) << /*declaration*/0;
7666 if (!NewRC != !OldRC) {
7673 llvm::FoldingSetNodeID OldRCID, NewRCID;
7674 OldRC->Profile(OldRCID, Context, /*Canonical=*/true);
7675 NewRC->Profile(NewRCID, Context, /*Canonical=*/true);
7676 if (OldRCID != NewRCID) {
7687 /// Check whether a template can be declared within this scope.
7689 /// If the template declaration is valid in this scope, returns
7690 /// false. Otherwise, issues a diagnostic and returns true.
7692 Sema::CheckTemplateDeclScope(Scope *S, TemplateParameterList *TemplateParams) {
7696 // Find the nearest enclosing declaration scope.
7697 while ((S->getFlags() & Scope::DeclScope) == 0 ||
7698 (S->getFlags() & Scope::TemplateParamScope) != 0)
7702 // A template [...] shall not have C linkage.
7703 DeclContext *Ctx = S->getEntity();
7704 assert(Ctx && "Unknown context");
7705 if (Ctx->isExternCContext()) {
7706 Diag(TemplateParams->getTemplateLoc(), diag::err_template_linkage)
7707 << TemplateParams->getSourceRange();
7708 if (const LinkageSpecDecl *LSD = Ctx->getExternCContext())
7709 Diag(LSD->getExternLoc(), diag::note_extern_c_begins_here);
7712 Ctx = Ctx->getRedeclContext();
7715 // A template-declaration can appear only as a namespace scope or
7716 // class scope declaration.
7718 if (Ctx->isFileContext())
7720 if (CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(Ctx)) {
7721 // C++ [temp.mem]p2:
7722 // A local class shall not have member templates.
7723 if (RD->isLocalClass())
7724 return Diag(TemplateParams->getTemplateLoc(),
7725 diag::err_template_inside_local_class)
7726 << TemplateParams->getSourceRange();
7732 return Diag(TemplateParams->getTemplateLoc(),
7733 diag::err_template_outside_namespace_or_class_scope)
7734 << TemplateParams->getSourceRange();
7737 /// Determine what kind of template specialization the given declaration
7739 static TemplateSpecializationKind getTemplateSpecializationKind(Decl *D) {
7741 return TSK_Undeclared;
7743 if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(D))
7744 return Record->getTemplateSpecializationKind();
7745 if (FunctionDecl *Function = dyn_cast<FunctionDecl>(D))
7746 return Function->getTemplateSpecializationKind();
7747 if (VarDecl *Var = dyn_cast<VarDecl>(D))
7748 return Var->getTemplateSpecializationKind();
7750 return TSK_Undeclared;
7753 /// Check whether a specialization is well-formed in the current
7756 /// This routine determines whether a template specialization can be declared
7757 /// in the current context (C++ [temp.expl.spec]p2).
7759 /// \param S the semantic analysis object for which this check is being
7762 /// \param Specialized the entity being specialized or instantiated, which
7763 /// may be a kind of template (class template, function template, etc.) or
7764 /// a member of a class template (member function, static data member,
7767 /// \param PrevDecl the previous declaration of this entity, if any.
7769 /// \param Loc the location of the explicit specialization or instantiation of
7772 /// \param IsPartialSpecialization whether this is a partial specialization of
7773 /// a class template.
7775 /// \returns true if there was an error that we cannot recover from, false
7777 static bool CheckTemplateSpecializationScope(Sema &S,
7778 NamedDecl *Specialized,
7779 NamedDecl *PrevDecl,
7781 bool IsPartialSpecialization) {
7782 // Keep these "kind" numbers in sync with the %select statements in the
7783 // various diagnostics emitted by this routine.
7785 if (isa<ClassTemplateDecl>(Specialized))
7786 EntityKind = IsPartialSpecialization? 1 : 0;
7787 else if (isa<VarTemplateDecl>(Specialized))
7788 EntityKind = IsPartialSpecialization ? 3 : 2;
7789 else if (isa<FunctionTemplateDecl>(Specialized))
7791 else if (isa<CXXMethodDecl>(Specialized))
7793 else if (isa<VarDecl>(Specialized))
7795 else if (isa<RecordDecl>(Specialized))
7797 else if (isa<EnumDecl>(Specialized) && S.getLangOpts().CPlusPlus11)
7800 S.Diag(Loc, diag::err_template_spec_unknown_kind)
7801 << S.getLangOpts().CPlusPlus11;
7802 S.Diag(Specialized->getLocation(), diag::note_specialized_entity);
7806 // C++ [temp.expl.spec]p2:
7807 // An explicit specialization may be declared in any scope in which
7808 // the corresponding primary template may be defined.
7809 if (S.CurContext->getRedeclContext()->isFunctionOrMethod()) {
7810 S.Diag(Loc, diag::err_template_spec_decl_function_scope)
7815 // C++ [temp.class.spec]p6:
7816 // A class template partial specialization may be declared in any
7817 // scope in which the primary template may be defined.
7818 DeclContext *SpecializedContext =
7819 Specialized->getDeclContext()->getRedeclContext();
7820 DeclContext *DC = S.CurContext->getRedeclContext();
7822 // Make sure that this redeclaration (or definition) occurs in the same
7823 // scope or an enclosing namespace.
7824 if (!(DC->isFileContext() ? DC->Encloses(SpecializedContext)
7825 : DC->Equals(SpecializedContext))) {
7826 if (isa<TranslationUnitDecl>(SpecializedContext))
7827 S.Diag(Loc, diag::err_template_spec_redecl_global_scope)
7828 << EntityKind << Specialized;
7830 auto *ND = cast<NamedDecl>(SpecializedContext);
7831 int Diag = diag::err_template_spec_redecl_out_of_scope;
7832 if (S.getLangOpts().MicrosoftExt && !DC->isRecord())
7833 Diag = diag::ext_ms_template_spec_redecl_out_of_scope;
7834 S.Diag(Loc, Diag) << EntityKind << Specialized
7835 << ND << isa<CXXRecordDecl>(ND);
7838 S.Diag(Specialized->getLocation(), diag::note_specialized_entity);
7840 // Don't allow specializing in the wrong class during error recovery.
7841 // Otherwise, things can go horribly wrong.
7849 static SourceRange findTemplateParameterInType(unsigned Depth, Expr *E) {
7850 if (!E->isTypeDependent())
7851 return SourceLocation();
7852 DependencyChecker Checker(Depth, /*IgnoreNonTypeDependent*/true);
7853 Checker.TraverseStmt(E);
7854 if (Checker.MatchLoc.isInvalid())
7855 return E->getSourceRange();
7856 return Checker.MatchLoc;
7859 static SourceRange findTemplateParameter(unsigned Depth, TypeLoc TL) {
7860 if (!TL.getType()->isDependentType())
7861 return SourceLocation();
7862 DependencyChecker Checker(Depth, /*IgnoreNonTypeDependent*/true);
7863 Checker.TraverseTypeLoc(TL);
7864 if (Checker.MatchLoc.isInvalid())
7865 return TL.getSourceRange();
7866 return Checker.MatchLoc;
7869 /// Subroutine of Sema::CheckTemplatePartialSpecializationArgs
7870 /// that checks non-type template partial specialization arguments.
7871 static bool CheckNonTypeTemplatePartialSpecializationArgs(
7872 Sema &S, SourceLocation TemplateNameLoc, NonTypeTemplateParmDecl *Param,
7873 const TemplateArgument *Args, unsigned NumArgs, bool IsDefaultArgument) {
7874 for (unsigned I = 0; I != NumArgs; ++I) {
7875 if (Args[I].getKind() == TemplateArgument::Pack) {
7876 if (CheckNonTypeTemplatePartialSpecializationArgs(
7877 S, TemplateNameLoc, Param, Args[I].pack_begin(),
7878 Args[I].pack_size(), IsDefaultArgument))
7884 if (Args[I].getKind() != TemplateArgument::Expression)
7887 Expr *ArgExpr = Args[I].getAsExpr();
7889 // We can have a pack expansion of any of the bullets below.
7890 if (PackExpansionExpr *Expansion = dyn_cast<PackExpansionExpr>(ArgExpr))
7891 ArgExpr = Expansion->getPattern();
7893 // Strip off any implicit casts we added as part of type checking.
7894 while (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(ArgExpr))
7895 ArgExpr = ICE->getSubExpr();
7897 // C++ [temp.class.spec]p8:
7898 // A non-type argument is non-specialized if it is the name of a
7899 // non-type parameter. All other non-type arguments are
7902 // Below, we check the two conditions that only apply to
7903 // specialized non-type arguments, so skip any non-specialized
7905 if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(ArgExpr))
7906 if (isa<NonTypeTemplateParmDecl>(DRE->getDecl()))
7909 // C++ [temp.class.spec]p9:
7910 // Within the argument list of a class template partial
7911 // specialization, the following restrictions apply:
7912 // -- A partially specialized non-type argument expression
7913 // shall not involve a template parameter of the partial
7914 // specialization except when the argument expression is a
7915 // simple identifier.
7916 // -- The type of a template parameter corresponding to a
7917 // specialized non-type argument shall not be dependent on a
7918 // parameter of the specialization.
7919 // DR1315 removes the first bullet, leaving an incoherent set of rules.
7920 // We implement a compromise between the original rules and DR1315:
7921 // -- A specialized non-type template argument shall not be
7922 // type-dependent and the corresponding template parameter
7923 // shall have a non-dependent type.
7924 SourceRange ParamUseRange =
7925 findTemplateParameterInType(Param->getDepth(), ArgExpr);
7926 if (ParamUseRange.isValid()) {
7927 if (IsDefaultArgument) {
7928 S.Diag(TemplateNameLoc,
7929 diag::err_dependent_non_type_arg_in_partial_spec);
7930 S.Diag(ParamUseRange.getBegin(),
7931 diag::note_dependent_non_type_default_arg_in_partial_spec)
7934 S.Diag(ParamUseRange.getBegin(),
7935 diag::err_dependent_non_type_arg_in_partial_spec)
7941 ParamUseRange = findTemplateParameter(
7942 Param->getDepth(), Param->getTypeSourceInfo()->getTypeLoc());
7943 if (ParamUseRange.isValid()) {
7944 S.Diag(IsDefaultArgument ? TemplateNameLoc : ArgExpr->getBeginLoc(),
7945 diag::err_dependent_typed_non_type_arg_in_partial_spec)
7946 << Param->getType();
7947 S.Diag(Param->getLocation(), diag::note_template_param_here)
7948 << (IsDefaultArgument ? ParamUseRange : SourceRange())
7957 /// Check the non-type template arguments of a class template
7958 /// partial specialization according to C++ [temp.class.spec]p9.
7960 /// \param TemplateNameLoc the location of the template name.
7961 /// \param PrimaryTemplate the template parameters of the primary class
7963 /// \param NumExplicit the number of explicitly-specified template arguments.
7964 /// \param TemplateArgs the template arguments of the class template
7965 /// partial specialization.
7967 /// \returns \c true if there was an error, \c false otherwise.
7968 bool Sema::CheckTemplatePartialSpecializationArgs(
7969 SourceLocation TemplateNameLoc, TemplateDecl *PrimaryTemplate,
7970 unsigned NumExplicit, ArrayRef<TemplateArgument> TemplateArgs) {
7971 // We have to be conservative when checking a template in a dependent
7973 if (PrimaryTemplate->getDeclContext()->isDependentContext())
7976 TemplateParameterList *TemplateParams =
7977 PrimaryTemplate->getTemplateParameters();
7978 for (unsigned I = 0, N = TemplateParams->size(); I != N; ++I) {
7979 NonTypeTemplateParmDecl *Param
7980 = dyn_cast<NonTypeTemplateParmDecl>(TemplateParams->getParam(I));
7984 if (CheckNonTypeTemplatePartialSpecializationArgs(*this, TemplateNameLoc,
7985 Param, &TemplateArgs[I],
7986 1, I >= NumExplicit))
7993 DeclResult Sema::ActOnClassTemplateSpecialization(
7994 Scope *S, unsigned TagSpec, TagUseKind TUK, SourceLocation KWLoc,
7995 SourceLocation ModulePrivateLoc, CXXScopeSpec &SS,
7996 TemplateIdAnnotation &TemplateId, const ParsedAttributesView &Attr,
7997 MultiTemplateParamsArg TemplateParameterLists, SkipBodyInfo *SkipBody) {
7998 assert(TUK != TUK_Reference && "References are not specializations");
8000 // NOTE: KWLoc is the location of the tag keyword. This will instead
8001 // store the location of the outermost template keyword in the declaration.
8002 SourceLocation TemplateKWLoc = TemplateParameterLists.size() > 0
8003 ? TemplateParameterLists[0]->getTemplateLoc() : KWLoc;
8004 SourceLocation TemplateNameLoc = TemplateId.TemplateNameLoc;
8005 SourceLocation LAngleLoc = TemplateId.LAngleLoc;
8006 SourceLocation RAngleLoc = TemplateId.RAngleLoc;
8008 // Find the class template we're specializing
8009 TemplateName Name = TemplateId.Template.get();
8010 ClassTemplateDecl *ClassTemplate
8011 = dyn_cast_or_null<ClassTemplateDecl>(Name.getAsTemplateDecl());
8013 if (!ClassTemplate) {
8014 Diag(TemplateNameLoc, diag::err_not_class_template_specialization)
8015 << (Name.getAsTemplateDecl() &&
8016 isa<TemplateTemplateParmDecl>(Name.getAsTemplateDecl()));
8020 bool isMemberSpecialization = false;
8021 bool isPartialSpecialization = false;
8023 // Check the validity of the template headers that introduce this
8025 // FIXME: We probably shouldn't complain about these headers for
8026 // friend declarations.
8027 bool Invalid = false;
8028 TemplateParameterList *TemplateParams =
8029 MatchTemplateParametersToScopeSpecifier(
8030 KWLoc, TemplateNameLoc, SS, &TemplateId,
8031 TemplateParameterLists, TUK == TUK_Friend, isMemberSpecialization,
8036 if (TemplateParams && TemplateParams->size() > 0) {
8037 isPartialSpecialization = true;
8039 if (TUK == TUK_Friend) {
8040 Diag(KWLoc, diag::err_partial_specialization_friend)
8041 << SourceRange(LAngleLoc, RAngleLoc);
8045 // C++ [temp.class.spec]p10:
8046 // The template parameter list of a specialization shall not
8047 // contain default template argument values.
8048 for (unsigned I = 0, N = TemplateParams->size(); I != N; ++I) {
8049 Decl *Param = TemplateParams->getParam(I);
8050 if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(Param)) {
8051 if (TTP->hasDefaultArgument()) {
8052 Diag(TTP->getDefaultArgumentLoc(),
8053 diag::err_default_arg_in_partial_spec);
8054 TTP->removeDefaultArgument();
8056 } else if (NonTypeTemplateParmDecl *NTTP
8057 = dyn_cast<NonTypeTemplateParmDecl>(Param)) {
8058 if (Expr *DefArg = NTTP->getDefaultArgument()) {
8059 Diag(NTTP->getDefaultArgumentLoc(),
8060 diag::err_default_arg_in_partial_spec)
8061 << DefArg->getSourceRange();
8062 NTTP->removeDefaultArgument();
8065 TemplateTemplateParmDecl *TTP = cast<TemplateTemplateParmDecl>(Param);
8066 if (TTP->hasDefaultArgument()) {
8067 Diag(TTP->getDefaultArgument().getLocation(),
8068 diag::err_default_arg_in_partial_spec)
8069 << TTP->getDefaultArgument().getSourceRange();
8070 TTP->removeDefaultArgument();
8074 } else if (TemplateParams) {
8075 if (TUK == TUK_Friend)
8076 Diag(KWLoc, diag::err_template_spec_friend)
8077 << FixItHint::CreateRemoval(
8078 SourceRange(TemplateParams->getTemplateLoc(),
8079 TemplateParams->getRAngleLoc()))
8080 << SourceRange(LAngleLoc, RAngleLoc);
8082 assert(TUK == TUK_Friend && "should have a 'template<>' for this decl");
8085 // Check that the specialization uses the same tag kind as the
8086 // original template.
8087 TagTypeKind Kind = TypeWithKeyword::getTagTypeKindForTypeSpec(TagSpec);
8088 assert(Kind != TTK_Enum && "Invalid enum tag in class template spec!");
8089 if (!isAcceptableTagRedeclaration(ClassTemplate->getTemplatedDecl(),
8090 Kind, TUK == TUK_Definition, KWLoc,
8091 ClassTemplate->getIdentifier())) {
8092 Diag(KWLoc, diag::err_use_with_wrong_tag)
8094 << FixItHint::CreateReplacement(KWLoc,
8095 ClassTemplate->getTemplatedDecl()->getKindName());
8096 Diag(ClassTemplate->getTemplatedDecl()->getLocation(),
8097 diag::note_previous_use);
8098 Kind = ClassTemplate->getTemplatedDecl()->getTagKind();
8101 // Translate the parser's template argument list in our AST format.
8102 TemplateArgumentListInfo TemplateArgs =
8103 makeTemplateArgumentListInfo(*this, TemplateId);
8105 // Check for unexpanded parameter packs in any of the template arguments.
8106 for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I)
8107 if (DiagnoseUnexpandedParameterPack(TemplateArgs[I],
8108 UPPC_PartialSpecialization))
8111 // Check that the template argument list is well-formed for this
8113 SmallVector<TemplateArgument, 4> Converted;
8114 if (CheckTemplateArgumentList(ClassTemplate, TemplateNameLoc,
8115 TemplateArgs, false, Converted,
8116 /*UpdateArgsWithConversion=*/true))
8119 // Find the class template (partial) specialization declaration that
8120 // corresponds to these arguments.
8121 if (isPartialSpecialization) {
8122 if (CheckTemplatePartialSpecializationArgs(TemplateNameLoc, ClassTemplate,
8123 TemplateArgs.size(), Converted))
8126 // FIXME: Move this to CheckTemplatePartialSpecializationArgs so we
8127 // also do it during instantiation.
8128 bool InstantiationDependent;
8129 if (!Name.isDependent() &&
8130 !TemplateSpecializationType::anyDependentTemplateArguments(
8131 TemplateArgs.arguments(), InstantiationDependent)) {
8132 Diag(TemplateNameLoc, diag::err_partial_spec_fully_specialized)
8133 << ClassTemplate->getDeclName();
8134 isPartialSpecialization = false;
8138 void *InsertPos = nullptr;
8139 ClassTemplateSpecializationDecl *PrevDecl = nullptr;
8141 if (isPartialSpecialization)
8142 PrevDecl = ClassTemplate->findPartialSpecialization(Converted,
8146 PrevDecl = ClassTemplate->findSpecialization(Converted, InsertPos);
8148 ClassTemplateSpecializationDecl *Specialization = nullptr;
8150 // Check whether we can declare a class template specialization in
8151 // the current scope.
8152 if (TUK != TUK_Friend &&
8153 CheckTemplateSpecializationScope(*this, ClassTemplate, PrevDecl,
8155 isPartialSpecialization))
8158 // The canonical type
8160 if (isPartialSpecialization) {
8161 // Build the canonical type that describes the converted template
8162 // arguments of the class template partial specialization.
8163 TemplateName CanonTemplate = Context.getCanonicalTemplateName(Name);
8164 CanonType = Context.getTemplateSpecializationType(CanonTemplate,
8167 if (Context.hasSameType(CanonType,
8168 ClassTemplate->getInjectedClassNameSpecialization()) &&
8169 (!Context.getLangOpts().CPlusPlus2a ||
8170 !TemplateParams->hasAssociatedConstraints())) {
8171 // C++ [temp.class.spec]p9b3:
8173 // -- The argument list of the specialization shall not be identical
8174 // to the implicit argument list of the primary template.
8176 // This rule has since been removed, because it's redundant given DR1495,
8177 // but we keep it because it produces better diagnostics and recovery.
8178 Diag(TemplateNameLoc, diag::err_partial_spec_args_match_primary_template)
8179 << /*class template*/0 << (TUK == TUK_Definition)
8180 << FixItHint::CreateRemoval(SourceRange(LAngleLoc, RAngleLoc));
8181 return CheckClassTemplate(S, TagSpec, TUK, KWLoc, SS,
8182 ClassTemplate->getIdentifier(),
8186 AS_none, /*ModulePrivateLoc=*/SourceLocation(),
8187 /*FriendLoc*/SourceLocation(),
8188 TemplateParameterLists.size() - 1,
8189 TemplateParameterLists.data());
8192 // Create a new class template partial specialization declaration node.
8193 ClassTemplatePartialSpecializationDecl *PrevPartial
8194 = cast_or_null<ClassTemplatePartialSpecializationDecl>(PrevDecl);
8195 ClassTemplatePartialSpecializationDecl *Partial
8196 = ClassTemplatePartialSpecializationDecl::Create(Context, Kind,
8197 ClassTemplate->getDeclContext(),
8198 KWLoc, TemplateNameLoc,
8205 SetNestedNameSpecifier(*this, Partial, SS);
8206 if (TemplateParameterLists.size() > 1 && SS.isSet()) {
8207 Partial->setTemplateParameterListsInfo(
8208 Context, TemplateParameterLists.drop_back(1));
8212 ClassTemplate->AddPartialSpecialization(Partial, InsertPos);
8213 Specialization = Partial;
8215 // If we are providing an explicit specialization of a member class
8216 // template specialization, make a note of that.
8217 if (PrevPartial && PrevPartial->getInstantiatedFromMember())
8218 PrevPartial->setMemberSpecialization();
8220 CheckTemplatePartialSpecialization(Partial);
8222 // Create a new class template specialization declaration node for
8223 // this explicit specialization or friend declaration.
8225 = ClassTemplateSpecializationDecl::Create(Context, Kind,
8226 ClassTemplate->getDeclContext(),
8227 KWLoc, TemplateNameLoc,
8231 SetNestedNameSpecifier(*this, Specialization, SS);
8232 if (TemplateParameterLists.size() > 0) {
8233 Specialization->setTemplateParameterListsInfo(Context,
8234 TemplateParameterLists);
8238 ClassTemplate->AddSpecialization(Specialization, InsertPos);
8240 if (CurContext->isDependentContext()) {
8241 TemplateName CanonTemplate = Context.getCanonicalTemplateName(Name);
8242 CanonType = Context.getTemplateSpecializationType(
8243 CanonTemplate, Converted);
8245 CanonType = Context.getTypeDeclType(Specialization);
8249 // C++ [temp.expl.spec]p6:
8250 // If a template, a member template or the member of a class template is
8251 // explicitly specialized then that specialization shall be declared
8252 // before the first use of that specialization that would cause an implicit
8253 // instantiation to take place, in every translation unit in which such a
8254 // use occurs; no diagnostic is required.
8255 if (PrevDecl && PrevDecl->getPointOfInstantiation().isValid()) {
8257 for (Decl *Prev = PrevDecl; Prev; Prev = Prev->getPreviousDecl()) {
8258 // Is there any previous explicit specialization declaration?
8259 if (getTemplateSpecializationKind(Prev) == TSK_ExplicitSpecialization) {
8266 SourceRange Range(TemplateNameLoc, RAngleLoc);
8267 Diag(TemplateNameLoc, diag::err_specialization_after_instantiation)
8268 << Context.getTypeDeclType(Specialization) << Range;
8270 Diag(PrevDecl->getPointOfInstantiation(),
8271 diag::note_instantiation_required_here)
8272 << (PrevDecl->getTemplateSpecializationKind()
8273 != TSK_ImplicitInstantiation);
8278 // If this is not a friend, note that this is an explicit specialization.
8279 if (TUK != TUK_Friend)
8280 Specialization->setSpecializationKind(TSK_ExplicitSpecialization);
8282 // Check that this isn't a redefinition of this specialization.
8283 if (TUK == TUK_Definition) {
8284 RecordDecl *Def = Specialization->getDefinition();
8285 NamedDecl *Hidden = nullptr;
8286 if (Def && SkipBody && !hasVisibleDefinition(Def, &Hidden)) {
8287 SkipBody->ShouldSkip = true;
8288 SkipBody->Previous = Def;
8289 makeMergedDefinitionVisible(Hidden);
8291 SourceRange Range(TemplateNameLoc, RAngleLoc);
8292 Diag(TemplateNameLoc, diag::err_redefinition) << Specialization << Range;
8293 Diag(Def->getLocation(), diag::note_previous_definition);
8294 Specialization->setInvalidDecl();
8299 ProcessDeclAttributeList(S, Specialization, Attr);
8301 // Add alignment attributes if necessary; these attributes are checked when
8302 // the ASTContext lays out the structure.
8303 if (TUK == TUK_Definition && (!SkipBody || !SkipBody->ShouldSkip)) {
8304 AddAlignmentAttributesForRecord(Specialization);
8305 AddMsStructLayoutForRecord(Specialization);
8308 if (ModulePrivateLoc.isValid())
8309 Diag(Specialization->getLocation(), diag::err_module_private_specialization)
8310 << (isPartialSpecialization? 1 : 0)
8311 << FixItHint::CreateRemoval(ModulePrivateLoc);
8313 // Build the fully-sugared type for this class template
8314 // specialization as the user wrote in the specialization
8315 // itself. This means that we'll pretty-print the type retrieved
8316 // from the specialization's declaration the way that the user
8317 // actually wrote the specialization, rather than formatting the
8318 // name based on the "canonical" representation used to store the
8319 // template arguments in the specialization.
8320 TypeSourceInfo *WrittenTy
8321 = Context.getTemplateSpecializationTypeInfo(Name, TemplateNameLoc,
8322 TemplateArgs, CanonType);
8323 if (TUK != TUK_Friend) {
8324 Specialization->setTypeAsWritten(WrittenTy);
8325 Specialization->setTemplateKeywordLoc(TemplateKWLoc);
8328 // C++ [temp.expl.spec]p9:
8329 // A template explicit specialization is in the scope of the
8330 // namespace in which the template was defined.
8332 // We actually implement this paragraph where we set the semantic
8333 // context (in the creation of the ClassTemplateSpecializationDecl),
8334 // but we also maintain the lexical context where the actual
8335 // definition occurs.
8336 Specialization->setLexicalDeclContext(CurContext);
8338 // We may be starting the definition of this specialization.
8339 if (TUK == TUK_Definition && (!SkipBody || !SkipBody->ShouldSkip))
8340 Specialization->startDefinition();
8342 if (TUK == TUK_Friend) {
8343 FriendDecl *Friend = FriendDecl::Create(Context, CurContext,
8347 Friend->setAccess(AS_public);
8348 CurContext->addDecl(Friend);
8350 // Add the specialization into its lexical context, so that it can
8351 // be seen when iterating through the list of declarations in that
8352 // context. However, specializations are not found by name lookup.
8353 CurContext->addDecl(Specialization);
8356 if (SkipBody && SkipBody->ShouldSkip)
8357 return SkipBody->Previous;
8359 return Specialization;
8362 Decl *Sema::ActOnTemplateDeclarator(Scope *S,
8363 MultiTemplateParamsArg TemplateParameterLists,
8365 Decl *NewDecl = HandleDeclarator(S, D, TemplateParameterLists);
8366 ActOnDocumentableDecl(NewDecl);
8370 Decl *Sema::ActOnConceptDefinition(Scope *S,
8371 MultiTemplateParamsArg TemplateParameterLists,
8372 IdentifierInfo *Name, SourceLocation NameLoc,
8373 Expr *ConstraintExpr) {
8374 DeclContext *DC = CurContext;
8376 if (!DC->getRedeclContext()->isFileContext()) {
8378 diag::err_concept_decls_may_only_appear_in_global_namespace_scope);
8382 if (TemplateParameterLists.size() > 1) {
8383 Diag(NameLoc, diag::err_concept_extra_headers);
8387 if (TemplateParameterLists.front()->size() == 0) {
8388 Diag(NameLoc, diag::err_concept_no_parameters);
8392 ConceptDecl *NewDecl = ConceptDecl::Create(Context, DC, NameLoc, Name,
8393 TemplateParameterLists.front(),
8396 if (NewDecl->hasAssociatedConstraints()) {
8397 // C++2a [temp.concept]p4:
8398 // A concept shall not have associated constraints.
8399 Diag(NameLoc, diag::err_concept_no_associated_constraints);
8400 NewDecl->setInvalidDecl();
8403 // Check for conflicting previous declaration.
8404 DeclarationNameInfo NameInfo(NewDecl->getDeclName(), NameLoc);
8405 LookupResult Previous(*this, NameInfo, LookupOrdinaryName,
8406 ForVisibleRedeclaration);
8407 LookupName(Previous, S);
8409 FilterLookupForScope(Previous, DC, S, /*ConsiderLinkage=*/false,
8410 /*AllowInlineNamespace*/false);
8411 if (!Previous.empty()) {
8412 auto *Old = Previous.getRepresentativeDecl();
8413 Diag(NameLoc, isa<ConceptDecl>(Old) ? diag::err_redefinition :
8414 diag::err_redefinition_different_kind) << NewDecl->getDeclName();
8415 Diag(Old->getLocation(), diag::note_previous_definition);
8418 ActOnDocumentableDecl(NewDecl);
8419 PushOnScopeChains(NewDecl, S);
8423 /// \brief Strips various properties off an implicit instantiation
8424 /// that has just been explicitly specialized.
8425 static void StripImplicitInstantiation(NamedDecl *D) {
8426 D->dropAttr<DLLImportAttr>();
8427 D->dropAttr<DLLExportAttr>();
8429 if (FunctionDecl *FD = dyn_cast<FunctionDecl>(D))
8430 FD->setInlineSpecified(false);
8433 /// Compute the diagnostic location for an explicit instantiation
8434 // declaration or definition.
8435 static SourceLocation DiagLocForExplicitInstantiation(
8436 NamedDecl* D, SourceLocation PointOfInstantiation) {
8437 // Explicit instantiations following a specialization have no effect and
8438 // hence no PointOfInstantiation. In that case, walk decl backwards
8439 // until a valid name loc is found.
8440 SourceLocation PrevDiagLoc = PointOfInstantiation;
8441 for (Decl *Prev = D; Prev && !PrevDiagLoc.isValid();
8442 Prev = Prev->getPreviousDecl()) {
8443 PrevDiagLoc = Prev->getLocation();
8445 assert(PrevDiagLoc.isValid() &&
8446 "Explicit instantiation without point of instantiation?");
8450 /// Diagnose cases where we have an explicit template specialization
8451 /// before/after an explicit template instantiation, producing diagnostics
8452 /// for those cases where they are required and determining whether the
8453 /// new specialization/instantiation will have any effect.
8455 /// \param NewLoc the location of the new explicit specialization or
8458 /// \param NewTSK the kind of the new explicit specialization or instantiation.
8460 /// \param PrevDecl the previous declaration of the entity.
8462 /// \param PrevTSK the kind of the old explicit specialization or instantiatin.
8464 /// \param PrevPointOfInstantiation if valid, indicates where the previus
8465 /// declaration was instantiated (either implicitly or explicitly).
8467 /// \param HasNoEffect will be set to true to indicate that the new
8468 /// specialization or instantiation has no effect and should be ignored.
8470 /// \returns true if there was an error that should prevent the introduction of
8471 /// the new declaration into the AST, false otherwise.
8473 Sema::CheckSpecializationInstantiationRedecl(SourceLocation NewLoc,
8474 TemplateSpecializationKind NewTSK,
8475 NamedDecl *PrevDecl,
8476 TemplateSpecializationKind PrevTSK,
8477 SourceLocation PrevPointOfInstantiation,
8478 bool &HasNoEffect) {
8479 HasNoEffect = false;
8482 case TSK_Undeclared:
8483 case TSK_ImplicitInstantiation:
8485 (PrevTSK == TSK_Undeclared || PrevTSK == TSK_ImplicitInstantiation) &&
8486 "previous declaration must be implicit!");
8489 case TSK_ExplicitSpecialization:
8491 case TSK_Undeclared:
8492 case TSK_ExplicitSpecialization:
8493 // Okay, we're just specializing something that is either already
8494 // explicitly specialized or has merely been mentioned without any
8498 case TSK_ImplicitInstantiation:
8499 if (PrevPointOfInstantiation.isInvalid()) {
8500 // The declaration itself has not actually been instantiated, so it is
8501 // still okay to specialize it.
8502 StripImplicitInstantiation(PrevDecl);
8508 case TSK_ExplicitInstantiationDeclaration:
8509 case TSK_ExplicitInstantiationDefinition:
8510 assert((PrevTSK == TSK_ImplicitInstantiation ||
8511 PrevPointOfInstantiation.isValid()) &&
8512 "Explicit instantiation without point of instantiation?");
8514 // C++ [temp.expl.spec]p6:
8515 // If a template, a member template or the member of a class template
8516 // is explicitly specialized then that specialization shall be declared
8517 // before the first use of that specialization that would cause an
8518 // implicit instantiation to take place, in every translation unit in
8519 // which such a use occurs; no diagnostic is required.
8520 for (Decl *Prev = PrevDecl; Prev; Prev = Prev->getPreviousDecl()) {
8521 // Is there any previous explicit specialization declaration?
8522 if (getTemplateSpecializationKind(Prev) == TSK_ExplicitSpecialization)
8526 Diag(NewLoc, diag::err_specialization_after_instantiation)
8528 Diag(PrevPointOfInstantiation, diag::note_instantiation_required_here)
8529 << (PrevTSK != TSK_ImplicitInstantiation);
8533 llvm_unreachable("The switch over PrevTSK must be exhaustive.");
8535 case TSK_ExplicitInstantiationDeclaration:
8537 case TSK_ExplicitInstantiationDeclaration:
8538 // This explicit instantiation declaration is redundant (that's okay).
8542 case TSK_Undeclared:
8543 case TSK_ImplicitInstantiation:
8544 // We're explicitly instantiating something that may have already been
8545 // implicitly instantiated; that's fine.
8548 case TSK_ExplicitSpecialization:
8549 // C++0x [temp.explicit]p4:
8550 // For a given set of template parameters, if an explicit instantiation
8551 // of a template appears after a declaration of an explicit
8552 // specialization for that template, the explicit instantiation has no
8557 case TSK_ExplicitInstantiationDefinition:
8558 // C++0x [temp.explicit]p10:
8559 // If an entity is the subject of both an explicit instantiation
8560 // declaration and an explicit instantiation definition in the same
8561 // translation unit, the definition shall follow the declaration.
8563 diag::err_explicit_instantiation_declaration_after_definition);
8565 // Explicit instantiations following a specialization have no effect and
8566 // hence no PrevPointOfInstantiation. In that case, walk decl backwards
8567 // until a valid name loc is found.
8568 Diag(DiagLocForExplicitInstantiation(PrevDecl, PrevPointOfInstantiation),
8569 diag::note_explicit_instantiation_definition_here);
8573 llvm_unreachable("Unexpected TemplateSpecializationKind!");
8575 case TSK_ExplicitInstantiationDefinition:
8577 case TSK_Undeclared:
8578 case TSK_ImplicitInstantiation:
8579 // We're explicitly instantiating something that may have already been
8580 // implicitly instantiated; that's fine.
8583 case TSK_ExplicitSpecialization:
8584 // C++ DR 259, C++0x [temp.explicit]p4:
8585 // For a given set of template parameters, if an explicit
8586 // instantiation of a template appears after a declaration of
8587 // an explicit specialization for that template, the explicit
8588 // instantiation has no effect.
8589 Diag(NewLoc, diag::warn_explicit_instantiation_after_specialization)
8591 Diag(PrevDecl->getLocation(),
8592 diag::note_previous_template_specialization);
8596 case TSK_ExplicitInstantiationDeclaration:
8597 // We're explicitly instantiating a definition for something for which we
8598 // were previously asked to suppress instantiations. That's fine.
8600 // C++0x [temp.explicit]p4:
8601 // For a given set of template parameters, if an explicit instantiation
8602 // of a template appears after a declaration of an explicit
8603 // specialization for that template, the explicit instantiation has no
8605 for (Decl *Prev = PrevDecl; Prev; Prev = Prev->getPreviousDecl()) {
8606 // Is there any previous explicit specialization declaration?
8607 if (getTemplateSpecializationKind(Prev) == TSK_ExplicitSpecialization) {
8615 case TSK_ExplicitInstantiationDefinition:
8616 // C++0x [temp.spec]p5:
8617 // For a given template and a given set of template-arguments,
8618 // - an explicit instantiation definition shall appear at most once
8621 // MSVCCompat: MSVC silently ignores duplicate explicit instantiations.
8622 Diag(NewLoc, (getLangOpts().MSVCCompat)
8623 ? diag::ext_explicit_instantiation_duplicate
8624 : diag::err_explicit_instantiation_duplicate)
8626 Diag(DiagLocForExplicitInstantiation(PrevDecl, PrevPointOfInstantiation),
8627 diag::note_previous_explicit_instantiation);
8633 llvm_unreachable("Missing specialization/instantiation case?");
8636 /// Perform semantic analysis for the given dependent function
8637 /// template specialization.
8639 /// The only possible way to get a dependent function template specialization
8640 /// is with a friend declaration, like so:
8643 /// template \<class T> void foo(T);
8644 /// template \<class T> class A {
8645 /// friend void foo<>(T);
8649 /// There really isn't any useful analysis we can do here, so we
8650 /// just store the information.
8652 Sema::CheckDependentFunctionTemplateSpecialization(FunctionDecl *FD,
8653 const TemplateArgumentListInfo &ExplicitTemplateArgs,
8654 LookupResult &Previous) {
8655 // Remove anything from Previous that isn't a function template in
8656 // the correct context.
8657 DeclContext *FDLookupContext = FD->getDeclContext()->getRedeclContext();
8658 LookupResult::Filter F = Previous.makeFilter();
8659 enum DiscardReason { NotAFunctionTemplate, NotAMemberOfEnclosing };
8660 SmallVector<std::pair<DiscardReason, Decl *>, 8> DiscardedCandidates;
8661 while (F.hasNext()) {
8662 NamedDecl *D = F.next()->getUnderlyingDecl();
8663 if (!isa<FunctionTemplateDecl>(D)) {
8665 DiscardedCandidates.push_back(std::make_pair(NotAFunctionTemplate, D));
8669 if (!FDLookupContext->InEnclosingNamespaceSetOf(
8670 D->getDeclContext()->getRedeclContext())) {
8672 DiscardedCandidates.push_back(std::make_pair(NotAMemberOfEnclosing, D));
8678 if (Previous.empty()) {
8679 Diag(FD->getLocation(),
8680 diag::err_dependent_function_template_spec_no_match);
8681 for (auto &P : DiscardedCandidates)
8682 Diag(P.second->getLocation(),
8683 diag::note_dependent_function_template_spec_discard_reason)
8688 FD->setDependentTemplateSpecialization(Context, Previous.asUnresolvedSet(),
8689 ExplicitTemplateArgs);
8693 /// Perform semantic analysis for the given function template
8696 /// This routine performs all of the semantic analysis required for an
8697 /// explicit function template specialization. On successful completion,
8698 /// the function declaration \p FD will become a function template
8701 /// \param FD the function declaration, which will be updated to become a
8702 /// function template specialization.
8704 /// \param ExplicitTemplateArgs the explicitly-provided template arguments,
8705 /// if any. Note that this may be valid info even when 0 arguments are
8706 /// explicitly provided as in, e.g., \c void sort<>(char*, char*);
8707 /// as it anyway contains info on the angle brackets locations.
8709 /// \param Previous the set of declarations that may be specialized by
8710 /// this function specialization.
8712 /// \param QualifiedFriend whether this is a lookup for a qualified friend
8713 /// declaration with no explicit template argument list that might be
8714 /// befriending a function template specialization.
8715 bool Sema::CheckFunctionTemplateSpecialization(
8716 FunctionDecl *FD, TemplateArgumentListInfo *ExplicitTemplateArgs,
8717 LookupResult &Previous, bool QualifiedFriend) {
8718 // The set of function template specializations that could match this
8719 // explicit function template specialization.
8720 UnresolvedSet<8> Candidates;
8721 TemplateSpecCandidateSet FailedCandidates(FD->getLocation(),
8722 /*ForTakingAddress=*/false);
8724 llvm::SmallDenseMap<FunctionDecl *, TemplateArgumentListInfo, 8>
8725 ConvertedTemplateArgs;
8727 DeclContext *FDLookupContext = FD->getDeclContext()->getRedeclContext();
8728 for (LookupResult::iterator I = Previous.begin(), E = Previous.end();
8730 NamedDecl *Ovl = (*I)->getUnderlyingDecl();
8731 if (FunctionTemplateDecl *FunTmpl = dyn_cast<FunctionTemplateDecl>(Ovl)) {
8732 // Only consider templates found within the same semantic lookup scope as
8734 if (!FDLookupContext->InEnclosingNamespaceSetOf(
8735 Ovl->getDeclContext()->getRedeclContext()))
8738 // When matching a constexpr member function template specialization
8739 // against the primary template, we don't yet know whether the
8740 // specialization has an implicit 'const' (because we don't know whether
8741 // it will be a static member function until we know which template it
8742 // specializes), so adjust it now assuming it specializes this template.
8743 QualType FT = FD->getType();
8744 if (FD->isConstexpr()) {
8745 CXXMethodDecl *OldMD =
8746 dyn_cast<CXXMethodDecl>(FunTmpl->getTemplatedDecl());
8747 if (OldMD && OldMD->isConst()) {
8748 const FunctionProtoType *FPT = FT->castAs<FunctionProtoType>();
8749 FunctionProtoType::ExtProtoInfo EPI = FPT->getExtProtoInfo();
8750 EPI.TypeQuals.addConst();
8751 FT = Context.getFunctionType(FPT->getReturnType(),
8752 FPT->getParamTypes(), EPI);
8756 TemplateArgumentListInfo Args;
8757 if (ExplicitTemplateArgs)
8758 Args = *ExplicitTemplateArgs;
8760 // C++ [temp.expl.spec]p11:
8761 // A trailing template-argument can be left unspecified in the
8762 // template-id naming an explicit function template specialization
8763 // provided it can be deduced from the function argument type.
8764 // Perform template argument deduction to determine whether we may be
8765 // specializing this template.
8766 // FIXME: It is somewhat wasteful to build
8767 TemplateDeductionInfo Info(FailedCandidates.getLocation());
8768 FunctionDecl *Specialization = nullptr;
8769 if (TemplateDeductionResult TDK = DeduceTemplateArguments(
8770 cast<FunctionTemplateDecl>(FunTmpl->getFirstDecl()),
8771 ExplicitTemplateArgs ? &Args : nullptr, FT, Specialization,
8773 // Template argument deduction failed; record why it failed, so
8774 // that we can provide nifty diagnostics.
8775 FailedCandidates.addCandidate().set(
8776 I.getPair(), FunTmpl->getTemplatedDecl(),
8777 MakeDeductionFailureInfo(Context, TDK, Info));
8782 // Target attributes are part of the cuda function signature, so
8783 // the deduced template's cuda target must match that of the
8784 // specialization. Given that C++ template deduction does not
8785 // take target attributes into account, we reject candidates
8786 // here that have a different target.
8787 if (LangOpts.CUDA &&
8788 IdentifyCUDATarget(Specialization,
8789 /* IgnoreImplicitHDAttr = */ true) !=
8790 IdentifyCUDATarget(FD, /* IgnoreImplicitHDAttr = */ true)) {
8791 FailedCandidates.addCandidate().set(
8792 I.getPair(), FunTmpl->getTemplatedDecl(),
8793 MakeDeductionFailureInfo(Context, TDK_CUDATargetMismatch, Info));
8797 // Record this candidate.
8798 if (ExplicitTemplateArgs)
8799 ConvertedTemplateArgs[Specialization] = std::move(Args);
8800 Candidates.addDecl(Specialization, I.getAccess());
8804 // For a qualified friend declaration (with no explicit marker to indicate
8805 // that a template specialization was intended), note all (template and
8806 // non-template) candidates.
8807 if (QualifiedFriend && Candidates.empty()) {
8808 Diag(FD->getLocation(), diag::err_qualified_friend_no_match)
8809 << FD->getDeclName() << FDLookupContext;
8810 // FIXME: We should form a single candidate list and diagnose all
8811 // candidates at once, to get proper sorting and limiting.
8812 for (auto *OldND : Previous) {
8813 if (auto *OldFD = dyn_cast<FunctionDecl>(OldND->getUnderlyingDecl()))
8814 NoteOverloadCandidate(OldND, OldFD, CRK_None, FD->getType(), false);
8816 FailedCandidates.NoteCandidates(*this, FD->getLocation());
8820 // Find the most specialized function template.
8821 UnresolvedSetIterator Result = getMostSpecialized(
8822 Candidates.begin(), Candidates.end(), FailedCandidates, FD->getLocation(),
8823 PDiag(diag::err_function_template_spec_no_match) << FD->getDeclName(),
8824 PDiag(diag::err_function_template_spec_ambiguous)
8825 << FD->getDeclName() << (ExplicitTemplateArgs != nullptr),
8826 PDiag(diag::note_function_template_spec_matched));
8828 if (Result == Candidates.end())
8831 // Ignore access information; it doesn't figure into redeclaration checking.
8832 FunctionDecl *Specialization = cast<FunctionDecl>(*Result);
8834 FunctionTemplateSpecializationInfo *SpecInfo
8835 = Specialization->getTemplateSpecializationInfo();
8836 assert(SpecInfo && "Function template specialization info missing?");
8838 // Note: do not overwrite location info if previous template
8839 // specialization kind was explicit.
8840 TemplateSpecializationKind TSK = SpecInfo->getTemplateSpecializationKind();
8841 if (TSK == TSK_Undeclared || TSK == TSK_ImplicitInstantiation) {
8842 Specialization->setLocation(FD->getLocation());
8843 Specialization->setLexicalDeclContext(FD->getLexicalDeclContext());
8844 // C++11 [dcl.constexpr]p1: An explicit specialization of a constexpr
8845 // function can differ from the template declaration with respect to
8846 // the constexpr specifier.
8847 // FIXME: We need an update record for this AST mutation.
8848 // FIXME: What if there are multiple such prior declarations (for instance,
8849 // from different modules)?
8850 Specialization->setConstexprKind(FD->getConstexprKind());
8853 // FIXME: Check if the prior specialization has a point of instantiation.
8854 // If so, we have run afoul of .
8856 // If this is a friend declaration, then we're not really declaring
8857 // an explicit specialization.
8858 bool isFriend = (FD->getFriendObjectKind() != Decl::FOK_None);
8860 // Check the scope of this explicit specialization.
8862 CheckTemplateSpecializationScope(*this,
8863 Specialization->getPrimaryTemplate(),
8864 Specialization, FD->getLocation(),
8868 // C++ [temp.expl.spec]p6:
8869 // If a template, a member template or the member of a class template is
8870 // explicitly specialized then that specialization shall be declared
8871 // before the first use of that specialization that would cause an implicit
8872 // instantiation to take place, in every translation unit in which such a
8873 // use occurs; no diagnostic is required.
8874 bool HasNoEffect = false;
8876 CheckSpecializationInstantiationRedecl(FD->getLocation(),
8877 TSK_ExplicitSpecialization,
8879 SpecInfo->getTemplateSpecializationKind(),
8880 SpecInfo->getPointOfInstantiation(),
8884 // Mark the prior declaration as an explicit specialization, so that later
8885 // clients know that this is an explicit specialization.
8887 // Since explicit specializations do not inherit '=delete' from their
8888 // primary function template - check if the 'specialization' that was
8889 // implicitly generated (during template argument deduction for partial
8890 // ordering) from the most specialized of all the function templates that
8891 // 'FD' could have been specializing, has a 'deleted' definition. If so,
8892 // first check that it was implicitly generated during template argument
8893 // deduction by making sure it wasn't referenced, and then reset the deleted
8894 // flag to not-deleted, so that we can inherit that information from 'FD'.
8895 if (Specialization->isDeleted() && !SpecInfo->isExplicitSpecialization() &&
8896 !Specialization->getCanonicalDecl()->isReferenced()) {
8897 // FIXME: This assert will not hold in the presence of modules.
8899 Specialization->getCanonicalDecl() == Specialization &&
8900 "This must be the only existing declaration of this specialization");
8901 // FIXME: We need an update record for this AST mutation.
8902 Specialization->setDeletedAsWritten(false);
8904 // FIXME: We need an update record for this AST mutation.
8905 SpecInfo->setTemplateSpecializationKind(TSK_ExplicitSpecialization);
8906 MarkUnusedFileScopedDecl(Specialization);
8909 // Turn the given function declaration into a function template
8910 // specialization, with the template arguments from the previous
8912 // Take copies of (semantic and syntactic) template argument lists.
8913 const TemplateArgumentList* TemplArgs = new (Context)
8914 TemplateArgumentList(Specialization->getTemplateSpecializationArgs());
8915 FD->setFunctionTemplateSpecialization(
8916 Specialization->getPrimaryTemplate(), TemplArgs, /*InsertPos=*/nullptr,
8917 SpecInfo->getTemplateSpecializationKind(),
8918 ExplicitTemplateArgs ? &ConvertedTemplateArgs[Specialization] : nullptr);
8920 // A function template specialization inherits the target attributes
8921 // of its template. (We require the attributes explicitly in the
8922 // code to match, but a template may have implicit attributes by
8923 // virtue e.g. of being constexpr, and it passes these implicit
8924 // attributes on to its specializations.)
8926 inheritCUDATargetAttrs(FD, *Specialization->getPrimaryTemplate());
8928 // The "previous declaration" for this function template specialization is
8929 // the prior function template specialization.
8931 Previous.addDecl(Specialization);
8935 /// Perform semantic analysis for the given non-template member
8938 /// This routine performs all of the semantic analysis required for an
8939 /// explicit member function specialization. On successful completion,
8940 /// the function declaration \p FD will become a member function
8943 /// \param Member the member declaration, which will be updated to become a
8946 /// \param Previous the set of declarations, one of which may be specialized
8947 /// by this function specialization; the set will be modified to contain the
8948 /// redeclared member.
8950 Sema::CheckMemberSpecialization(NamedDecl *Member, LookupResult &Previous) {
8951 assert(!isa<TemplateDecl>(Member) && "Only for non-template members");
8953 // Try to find the member we are instantiating.
8954 NamedDecl *FoundInstantiation = nullptr;
8955 NamedDecl *Instantiation = nullptr;
8956 NamedDecl *InstantiatedFrom = nullptr;
8957 MemberSpecializationInfo *MSInfo = nullptr;
8959 if (Previous.empty()) {
8960 // Nowhere to look anyway.
8961 } else if (FunctionDecl *Function = dyn_cast<FunctionDecl>(Member)) {
8962 for (LookupResult::iterator I = Previous.begin(), E = Previous.end();
8964 NamedDecl *D = (*I)->getUnderlyingDecl();
8965 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(D)) {
8966 QualType Adjusted = Function->getType();
8967 if (!hasExplicitCallingConv(Adjusted))
8968 Adjusted = adjustCCAndNoReturn(Adjusted, Method->getType());
8969 // This doesn't handle deduced return types, but both function
8970 // declarations should be undeduced at this point.
8971 if (Context.hasSameType(Adjusted, Method->getType())) {
8972 FoundInstantiation = *I;
8973 Instantiation = Method;
8974 InstantiatedFrom = Method->getInstantiatedFromMemberFunction();
8975 MSInfo = Method->getMemberSpecializationInfo();
8980 } else if (isa<VarDecl>(Member)) {
8982 if (Previous.isSingleResult() &&
8983 (PrevVar = dyn_cast<VarDecl>(Previous.getFoundDecl())))
8984 if (PrevVar->isStaticDataMember()) {
8985 FoundInstantiation = Previous.getRepresentativeDecl();
8986 Instantiation = PrevVar;
8987 InstantiatedFrom = PrevVar->getInstantiatedFromStaticDataMember();
8988 MSInfo = PrevVar->getMemberSpecializationInfo();
8990 } else if (isa<RecordDecl>(Member)) {
8991 CXXRecordDecl *PrevRecord;
8992 if (Previous.isSingleResult() &&
8993 (PrevRecord = dyn_cast<CXXRecordDecl>(Previous.getFoundDecl()))) {
8994 FoundInstantiation = Previous.getRepresentativeDecl();
8995 Instantiation = PrevRecord;
8996 InstantiatedFrom = PrevRecord->getInstantiatedFromMemberClass();
8997 MSInfo = PrevRecord->getMemberSpecializationInfo();
8999 } else if (isa<EnumDecl>(Member)) {
9001 if (Previous.isSingleResult() &&
9002 (PrevEnum = dyn_cast<EnumDecl>(Previous.getFoundDecl()))) {
9003 FoundInstantiation = Previous.getRepresentativeDecl();
9004 Instantiation = PrevEnum;
9005 InstantiatedFrom = PrevEnum->getInstantiatedFromMemberEnum();
9006 MSInfo = PrevEnum->getMemberSpecializationInfo();
9010 if (!Instantiation) {
9011 // There is no previous declaration that matches. Since member
9012 // specializations are always out-of-line, the caller will complain about
9013 // this mismatch later.
9017 // A member specialization in a friend declaration isn't really declaring
9018 // an explicit specialization, just identifying a specific (possibly implicit)
9019 // specialization. Don't change the template specialization kind.
9021 // FIXME: Is this really valid? Other compilers reject.
9022 if (Member->getFriendObjectKind() != Decl::FOK_None) {
9023 // Preserve instantiation information.
9024 if (InstantiatedFrom && isa<CXXMethodDecl>(Member)) {
9025 cast<CXXMethodDecl>(Member)->setInstantiationOfMemberFunction(
9026 cast<CXXMethodDecl>(InstantiatedFrom),
9027 cast<CXXMethodDecl>(Instantiation)->getTemplateSpecializationKind());
9028 } else if (InstantiatedFrom && isa<CXXRecordDecl>(Member)) {
9029 cast<CXXRecordDecl>(Member)->setInstantiationOfMemberClass(
9030 cast<CXXRecordDecl>(InstantiatedFrom),
9031 cast<CXXRecordDecl>(Instantiation)->getTemplateSpecializationKind());
9035 Previous.addDecl(FoundInstantiation);
9039 // Make sure that this is a specialization of a member.
9040 if (!InstantiatedFrom) {
9041 Diag(Member->getLocation(), diag::err_spec_member_not_instantiated)
9043 Diag(Instantiation->getLocation(), diag::note_specialized_decl);
9047 // C++ [temp.expl.spec]p6:
9048 // If a template, a member template or the member of a class template is
9049 // explicitly specialized then that specialization shall be declared
9050 // before the first use of that specialization that would cause an implicit
9051 // instantiation to take place, in every translation unit in which such a
9052 // use occurs; no diagnostic is required.
9053 assert(MSInfo && "Member specialization info missing?");
9055 bool HasNoEffect = false;
9056 if (CheckSpecializationInstantiationRedecl(Member->getLocation(),
9057 TSK_ExplicitSpecialization,
9059 MSInfo->getTemplateSpecializationKind(),
9060 MSInfo->getPointOfInstantiation(),
9064 // Check the scope of this explicit specialization.
9065 if (CheckTemplateSpecializationScope(*this,
9067 Instantiation, Member->getLocation(),
9071 // Note that this member specialization is an "instantiation of" the
9072 // corresponding member of the original template.
9073 if (auto *MemberFunction = dyn_cast<FunctionDecl>(Member)) {
9074 FunctionDecl *InstantiationFunction = cast<FunctionDecl>(Instantiation);
9075 if (InstantiationFunction->getTemplateSpecializationKind() ==
9076 TSK_ImplicitInstantiation) {
9077 // Explicit specializations of member functions of class templates do not
9078 // inherit '=delete' from the member function they are specializing.
9079 if (InstantiationFunction->isDeleted()) {
9080 // FIXME: This assert will not hold in the presence of modules.
9081 assert(InstantiationFunction->getCanonicalDecl() ==
9082 InstantiationFunction);
9083 // FIXME: We need an update record for this AST mutation.
9084 InstantiationFunction->setDeletedAsWritten(false);
9088 MemberFunction->setInstantiationOfMemberFunction(
9089 cast<CXXMethodDecl>(InstantiatedFrom), TSK_ExplicitSpecialization);
9090 } else if (auto *MemberVar = dyn_cast<VarDecl>(Member)) {
9091 MemberVar->setInstantiationOfStaticDataMember(
9092 cast<VarDecl>(InstantiatedFrom), TSK_ExplicitSpecialization);
9093 } else if (auto *MemberClass = dyn_cast<CXXRecordDecl>(Member)) {
9094 MemberClass->setInstantiationOfMemberClass(
9095 cast<CXXRecordDecl>(InstantiatedFrom), TSK_ExplicitSpecialization);
9096 } else if (auto *MemberEnum = dyn_cast<EnumDecl>(Member)) {
9097 MemberEnum->setInstantiationOfMemberEnum(
9098 cast<EnumDecl>(InstantiatedFrom), TSK_ExplicitSpecialization);
9100 llvm_unreachable("unknown member specialization kind");
9103 // Save the caller the trouble of having to figure out which declaration
9104 // this specialization matches.
9106 Previous.addDecl(FoundInstantiation);
9110 /// Complete the explicit specialization of a member of a class template by
9111 /// updating the instantiated member to be marked as an explicit specialization.
9113 /// \param OrigD The member declaration instantiated from the template.
9114 /// \param Loc The location of the explicit specialization of the member.
9115 template<typename DeclT>
9116 static void completeMemberSpecializationImpl(Sema &S, DeclT *OrigD,
9117 SourceLocation Loc) {
9118 if (OrigD->getTemplateSpecializationKind() != TSK_ImplicitInstantiation)
9121 // FIXME: Inform AST mutation listeners of this AST mutation.
9122 // FIXME: If there are multiple in-class declarations of the member (from
9123 // multiple modules, or a declaration and later definition of a member type),
9124 // should we update all of them?
9125 OrigD->setTemplateSpecializationKind(TSK_ExplicitSpecialization);
9126 OrigD->setLocation(Loc);
9129 void Sema::CompleteMemberSpecialization(NamedDecl *Member,
9130 LookupResult &Previous) {
9131 NamedDecl *Instantiation = cast<NamedDecl>(Member->getCanonicalDecl());
9132 if (Instantiation == Member)
9135 if (auto *Function = dyn_cast<CXXMethodDecl>(Instantiation))
9136 completeMemberSpecializationImpl(*this, Function, Member->getLocation());
9137 else if (auto *Var = dyn_cast<VarDecl>(Instantiation))
9138 completeMemberSpecializationImpl(*this, Var, Member->getLocation());
9139 else if (auto *Record = dyn_cast<CXXRecordDecl>(Instantiation))
9140 completeMemberSpecializationImpl(*this, Record, Member->getLocation());
9141 else if (auto *Enum = dyn_cast<EnumDecl>(Instantiation))
9142 completeMemberSpecializationImpl(*this, Enum, Member->getLocation());
9144 llvm_unreachable("unknown member specialization kind");
9147 /// Check the scope of an explicit instantiation.
9149 /// \returns true if a serious error occurs, false otherwise.
9150 static bool CheckExplicitInstantiationScope(Sema &S, NamedDecl *D,
9151 SourceLocation InstLoc,
9152 bool WasQualifiedName) {
9153 DeclContext *OrigContext= D->getDeclContext()->getEnclosingNamespaceContext();
9154 DeclContext *CurContext = S.CurContext->getRedeclContext();
9156 if (CurContext->isRecord()) {
9157 S.Diag(InstLoc, diag::err_explicit_instantiation_in_class)
9162 // C++11 [temp.explicit]p3:
9163 // An explicit instantiation shall appear in an enclosing namespace of its
9164 // template. If the name declared in the explicit instantiation is an
9165 // unqualified name, the explicit instantiation shall appear in the
9166 // namespace where its template is declared or, if that namespace is inline
9167 // (7.3.1), any namespace from its enclosing namespace set.
9169 // This is DR275, which we do not retroactively apply to C++98/03.
9170 if (WasQualifiedName) {
9171 if (CurContext->Encloses(OrigContext))
9174 if (CurContext->InEnclosingNamespaceSetOf(OrigContext))
9178 if (NamespaceDecl *NS = dyn_cast<NamespaceDecl>(OrigContext)) {
9179 if (WasQualifiedName)
9181 S.getLangOpts().CPlusPlus11?
9182 diag::err_explicit_instantiation_out_of_scope :
9183 diag::warn_explicit_instantiation_out_of_scope_0x)
9187 S.getLangOpts().CPlusPlus11?
9188 diag::err_explicit_instantiation_unqualified_wrong_namespace :
9189 diag::warn_explicit_instantiation_unqualified_wrong_namespace_0x)
9193 S.getLangOpts().CPlusPlus11?
9194 diag::err_explicit_instantiation_must_be_global :
9195 diag::warn_explicit_instantiation_must_be_global_0x)
9197 S.Diag(D->getLocation(), diag::note_explicit_instantiation_here);
9201 /// Common checks for whether an explicit instantiation of \p D is valid.
9202 static bool CheckExplicitInstantiation(Sema &S, NamedDecl *D,
9203 SourceLocation InstLoc,
9204 bool WasQualifiedName,
9205 TemplateSpecializationKind TSK) {
9206 // C++ [temp.explicit]p13:
9207 // An explicit instantiation declaration shall not name a specialization of
9208 // a template with internal linkage.
9209 if (TSK == TSK_ExplicitInstantiationDeclaration &&
9210 D->getFormalLinkage() == InternalLinkage) {
9211 S.Diag(InstLoc, diag::err_explicit_instantiation_internal_linkage) << D;
9215 // C++11 [temp.explicit]p3: [DR 275]
9216 // An explicit instantiation shall appear in an enclosing namespace of its
9218 if (CheckExplicitInstantiationScope(S, D, InstLoc, WasQualifiedName))
9224 /// Determine whether the given scope specifier has a template-id in it.
9225 static bool ScopeSpecifierHasTemplateId(const CXXScopeSpec &SS) {
9229 // C++11 [temp.explicit]p3:
9230 // If the explicit instantiation is for a member function, a member class
9231 // or a static data member of a class template specialization, the name of
9232 // the class template specialization in the qualified-id for the member
9233 // name shall be a simple-template-id.
9235 // C++98 has the same restriction, just worded differently.
9236 for (NestedNameSpecifier *NNS = SS.getScopeRep(); NNS;
9237 NNS = NNS->getPrefix())
9238 if (const Type *T = NNS->getAsType())
9239 if (isa<TemplateSpecializationType>(T))
9245 /// Make a dllexport or dllimport attr on a class template specialization take
9247 static void dllExportImportClassTemplateSpecialization(
9248 Sema &S, ClassTemplateSpecializationDecl *Def) {
9249 auto *A = cast_or_null<InheritableAttr>(getDLLAttr(Def));
9250 assert(A && "dllExportImportClassTemplateSpecialization called "
9251 "on Def without dllexport or dllimport");
9253 // We reject explicit instantiations in class scope, so there should
9254 // never be any delayed exported classes to worry about.
9255 assert(S.DelayedDllExportClasses.empty() &&
9256 "delayed exports present at explicit instantiation");
9257 S.checkClassLevelDLLAttribute(Def);
9259 // Propagate attribute to base class templates.
9260 for (auto &B : Def->bases()) {
9261 if (auto *BT = dyn_cast_or_null<ClassTemplateSpecializationDecl>(
9262 B.getType()->getAsCXXRecordDecl()))
9263 S.propagateDLLAttrToBaseClassTemplate(Def, A, BT, B.getBeginLoc());
9266 S.referenceDLLExportedClassMethods();
9269 // Explicit instantiation of a class template specialization
9270 DeclResult Sema::ActOnExplicitInstantiation(
9271 Scope *S, SourceLocation ExternLoc, SourceLocation TemplateLoc,
9272 unsigned TagSpec, SourceLocation KWLoc, const CXXScopeSpec &SS,
9273 TemplateTy TemplateD, SourceLocation TemplateNameLoc,
9274 SourceLocation LAngleLoc, ASTTemplateArgsPtr TemplateArgsIn,
9275 SourceLocation RAngleLoc, const ParsedAttributesView &Attr) {
9276 // Find the class template we're specializing
9277 TemplateName Name = TemplateD.get();
9278 TemplateDecl *TD = Name.getAsTemplateDecl();
9279 // Check that the specialization uses the same tag kind as the
9280 // original template.
9281 TagTypeKind Kind = TypeWithKeyword::getTagTypeKindForTypeSpec(TagSpec);
9282 assert(Kind != TTK_Enum &&
9283 "Invalid enum tag in class template explicit instantiation!");
9285 ClassTemplateDecl *ClassTemplate = dyn_cast<ClassTemplateDecl>(TD);
9287 if (!ClassTemplate) {
9288 NonTagKind NTK = getNonTagTypeDeclKind(TD, Kind);
9289 Diag(TemplateNameLoc, diag::err_tag_reference_non_tag) << TD << NTK << Kind;
9290 Diag(TD->getLocation(), diag::note_previous_use);
9294 if (!isAcceptableTagRedeclaration(ClassTemplate->getTemplatedDecl(),
9295 Kind, /*isDefinition*/false, KWLoc,
9296 ClassTemplate->getIdentifier())) {
9297 Diag(KWLoc, diag::err_use_with_wrong_tag)
9299 << FixItHint::CreateReplacement(KWLoc,
9300 ClassTemplate->getTemplatedDecl()->getKindName());
9301 Diag(ClassTemplate->getTemplatedDecl()->getLocation(),
9302 diag::note_previous_use);
9303 Kind = ClassTemplate->getTemplatedDecl()->getTagKind();
9306 // C++0x [temp.explicit]p2:
9307 // There are two forms of explicit instantiation: an explicit instantiation
9308 // definition and an explicit instantiation declaration. An explicit
9309 // instantiation declaration begins with the extern keyword. [...]
9310 TemplateSpecializationKind TSK = ExternLoc.isInvalid()
9311 ? TSK_ExplicitInstantiationDefinition
9312 : TSK_ExplicitInstantiationDeclaration;
9314 if (TSK == TSK_ExplicitInstantiationDeclaration &&
9315 !Context.getTargetInfo().getTriple().isWindowsGNUEnvironment()) {
9316 // Check for dllexport class template instantiation declarations,
9317 // except for MinGW mode.
9318 for (const ParsedAttr &AL : Attr) {
9319 if (AL.getKind() == ParsedAttr::AT_DLLExport) {
9321 diag::warn_attribute_dllexport_explicit_instantiation_decl);
9322 Diag(AL.getLoc(), diag::note_attribute);
9327 if (auto *A = ClassTemplate->getTemplatedDecl()->getAttr<DLLExportAttr>()) {
9329 diag::warn_attribute_dllexport_explicit_instantiation_decl);
9330 Diag(A->getLocation(), diag::note_attribute);
9334 // In MSVC mode, dllimported explicit instantiation definitions are treated as
9335 // instantiation declarations for most purposes.
9336 bool DLLImportExplicitInstantiationDef = false;
9337 if (TSK == TSK_ExplicitInstantiationDefinition &&
9338 Context.getTargetInfo().getCXXABI().isMicrosoft()) {
9339 // Check for dllimport class template instantiation definitions.
9341 ClassTemplate->getTemplatedDecl()->getAttr<DLLImportAttr>();
9342 for (const ParsedAttr &AL : Attr) {
9343 if (AL.getKind() == ParsedAttr::AT_DLLImport)
9345 if (AL.getKind() == ParsedAttr::AT_DLLExport) {
9346 // dllexport trumps dllimport here.
9352 TSK = TSK_ExplicitInstantiationDeclaration;
9353 DLLImportExplicitInstantiationDef = true;
9357 // Translate the parser's template argument list in our AST format.
9358 TemplateArgumentListInfo TemplateArgs(LAngleLoc, RAngleLoc);
9359 translateTemplateArguments(TemplateArgsIn, TemplateArgs);
9361 // Check that the template argument list is well-formed for this
9363 SmallVector<TemplateArgument, 4> Converted;
9364 if (CheckTemplateArgumentList(ClassTemplate, TemplateNameLoc,
9365 TemplateArgs, false, Converted,
9366 /*UpdateArgsWithConversion=*/true))
9369 // Find the class template specialization declaration that
9370 // corresponds to these arguments.
9371 void *InsertPos = nullptr;
9372 ClassTemplateSpecializationDecl *PrevDecl
9373 = ClassTemplate->findSpecialization(Converted, InsertPos);
9375 TemplateSpecializationKind PrevDecl_TSK
9376 = PrevDecl ? PrevDecl->getTemplateSpecializationKind() : TSK_Undeclared;
9378 if (TSK == TSK_ExplicitInstantiationDefinition && PrevDecl != nullptr &&
9379 Context.getTargetInfo().getTriple().isWindowsGNUEnvironment()) {
9380 // Check for dllexport class template instantiation definitions in MinGW
9381 // mode, if a previous declaration of the instantiation was seen.
9382 for (const ParsedAttr &AL : Attr) {
9383 if (AL.getKind() == ParsedAttr::AT_DLLExport) {
9385 diag::warn_attribute_dllexport_explicit_instantiation_def);
9391 if (CheckExplicitInstantiation(*this, ClassTemplate, TemplateNameLoc,
9395 ClassTemplateSpecializationDecl *Specialization = nullptr;
9397 bool HasNoEffect = false;
9399 if (CheckSpecializationInstantiationRedecl(TemplateNameLoc, TSK,
9400 PrevDecl, PrevDecl_TSK,
9401 PrevDecl->getPointOfInstantiation(),
9405 // Even though HasNoEffect == true means that this explicit instantiation
9406 // has no effect on semantics, we go on to put its syntax in the AST.
9408 if (PrevDecl_TSK == TSK_ImplicitInstantiation ||
9409 PrevDecl_TSK == TSK_Undeclared) {
9410 // Since the only prior class template specialization with these
9411 // arguments was referenced but not declared, reuse that
9412 // declaration node as our own, updating the source location
9413 // for the template name to reflect our new declaration.
9414 // (Other source locations will be updated later.)
9415 Specialization = PrevDecl;
9416 Specialization->setLocation(TemplateNameLoc);
9420 if (PrevDecl_TSK == TSK_ExplicitInstantiationDeclaration &&
9421 DLLImportExplicitInstantiationDef) {
9422 // The new specialization might add a dllimport attribute.
9423 HasNoEffect = false;
9427 if (!Specialization) {
9428 // Create a new class template specialization declaration node for
9429 // this explicit specialization.
9431 = ClassTemplateSpecializationDecl::Create(Context, Kind,
9432 ClassTemplate->getDeclContext(),
9433 KWLoc, TemplateNameLoc,
9437 SetNestedNameSpecifier(*this, Specialization, SS);
9439 if (!HasNoEffect && !PrevDecl) {
9440 // Insert the new specialization.
9441 ClassTemplate->AddSpecialization(Specialization, InsertPos);
9445 // Build the fully-sugared type for this explicit instantiation as
9446 // the user wrote in the explicit instantiation itself. This means
9447 // that we'll pretty-print the type retrieved from the
9448 // specialization's declaration the way that the user actually wrote
9449 // the explicit instantiation, rather than formatting the name based
9450 // on the "canonical" representation used to store the template
9451 // arguments in the specialization.
9452 TypeSourceInfo *WrittenTy
9453 = Context.getTemplateSpecializationTypeInfo(Name, TemplateNameLoc,
9455 Context.getTypeDeclType(Specialization));
9456 Specialization->setTypeAsWritten(WrittenTy);
9458 // Set source locations for keywords.
9459 Specialization->setExternLoc(ExternLoc);
9460 Specialization->setTemplateKeywordLoc(TemplateLoc);
9461 Specialization->setBraceRange(SourceRange());
9463 bool PreviouslyDLLExported = Specialization->hasAttr<DLLExportAttr>();
9464 ProcessDeclAttributeList(S, Specialization, Attr);
9466 // Add the explicit instantiation into its lexical context. However,
9467 // since explicit instantiations are never found by name lookup, we
9468 // just put it into the declaration context directly.
9469 Specialization->setLexicalDeclContext(CurContext);
9470 CurContext->addDecl(Specialization);
9472 // Syntax is now OK, so return if it has no other effect on semantics.
9474 // Set the template specialization kind.
9475 Specialization->setTemplateSpecializationKind(TSK);
9476 return Specialization;
9479 // C++ [temp.explicit]p3:
9480 // A definition of a class template or class member template
9481 // shall be in scope at the point of the explicit instantiation of
9482 // the class template or class member template.
9484 // This check comes when we actually try to perform the
9486 ClassTemplateSpecializationDecl *Def
9487 = cast_or_null<ClassTemplateSpecializationDecl>(
9488 Specialization->getDefinition());
9490 InstantiateClassTemplateSpecialization(TemplateNameLoc, Specialization, TSK);
9491 else if (TSK == TSK_ExplicitInstantiationDefinition) {
9492 MarkVTableUsed(TemplateNameLoc, Specialization, true);
9493 Specialization->setPointOfInstantiation(Def->getPointOfInstantiation());
9496 // Instantiate the members of this class template specialization.
9497 Def = cast_or_null<ClassTemplateSpecializationDecl>(
9498 Specialization->getDefinition());
9500 TemplateSpecializationKind Old_TSK = Def->getTemplateSpecializationKind();
9501 // Fix a TSK_ExplicitInstantiationDeclaration followed by a
9502 // TSK_ExplicitInstantiationDefinition
9503 if (Old_TSK == TSK_ExplicitInstantiationDeclaration &&
9504 (TSK == TSK_ExplicitInstantiationDefinition ||
9505 DLLImportExplicitInstantiationDef)) {
9506 // FIXME: Need to notify the ASTMutationListener that we did this.
9507 Def->setTemplateSpecializationKind(TSK);
9509 if (!getDLLAttr(Def) && getDLLAttr(Specialization) &&
9510 (Context.getTargetInfo().getCXXABI().isMicrosoft() ||
9511 Context.getTargetInfo().getTriple().isWindowsItaniumEnvironment())) {
9512 // In the MS ABI, an explicit instantiation definition can add a dll
9513 // attribute to a template with a previous instantiation declaration.
9514 // MinGW doesn't allow this.
9515 auto *A = cast<InheritableAttr>(
9516 getDLLAttr(Specialization)->clone(getASTContext()));
9517 A->setInherited(true);
9519 dllExportImportClassTemplateSpecialization(*this, Def);
9523 // Fix a TSK_ImplicitInstantiation followed by a
9524 // TSK_ExplicitInstantiationDefinition
9525 bool NewlyDLLExported =
9526 !PreviouslyDLLExported && Specialization->hasAttr<DLLExportAttr>();
9527 if (Old_TSK == TSK_ImplicitInstantiation && NewlyDLLExported &&
9528 (Context.getTargetInfo().getCXXABI().isMicrosoft() ||
9529 Context.getTargetInfo().getTriple().isWindowsItaniumEnvironment())) {
9530 // In the MS ABI, an explicit instantiation definition can add a dll
9531 // attribute to a template with a previous implicit instantiation.
9532 // MinGW doesn't allow this. We limit clang to only adding dllexport, to
9533 // avoid potentially strange codegen behavior. For example, if we extend
9534 // this conditional to dllimport, and we have a source file calling a
9535 // method on an implicitly instantiated template class instance and then
9536 // declaring a dllimport explicit instantiation definition for the same
9537 // template class, the codegen for the method call will not respect the
9538 // dllimport, while it will with cl. The Def will already have the DLL
9539 // attribute, since the Def and Specialization will be the same in the
9540 // case of Old_TSK == TSK_ImplicitInstantiation, and we already added the
9541 // attribute to the Specialization; we just need to make it take effect.
9542 assert(Def == Specialization &&
9543 "Def and Specialization should match for implicit instantiation");
9544 dllExportImportClassTemplateSpecialization(*this, Def);
9547 // In MinGW mode, export the template instantiation if the declaration
9548 // was marked dllexport.
9549 if (PrevDecl_TSK == TSK_ExplicitInstantiationDeclaration &&
9550 Context.getTargetInfo().getTriple().isWindowsGNUEnvironment() &&
9551 PrevDecl->hasAttr<DLLExportAttr>()) {
9552 dllExportImportClassTemplateSpecialization(*this, Def);
9555 // Set the template specialization kind. Make sure it is set before
9556 // instantiating the members which will trigger ASTConsumer callbacks.
9557 Specialization->setTemplateSpecializationKind(TSK);
9558 InstantiateClassTemplateSpecializationMembers(TemplateNameLoc, Def, TSK);
9561 // Set the template specialization kind.
9562 Specialization->setTemplateSpecializationKind(TSK);
9565 return Specialization;
9568 // Explicit instantiation of a member class of a class template.
9570 Sema::ActOnExplicitInstantiation(Scope *S, SourceLocation ExternLoc,
9571 SourceLocation TemplateLoc, unsigned TagSpec,
9572 SourceLocation KWLoc, CXXScopeSpec &SS,
9573 IdentifierInfo *Name, SourceLocation NameLoc,
9574 const ParsedAttributesView &Attr) {
9577 bool IsDependent = false;
9578 Decl *TagD = ActOnTag(S, TagSpec, Sema::TUK_Reference,
9579 KWLoc, SS, Name, NameLoc, Attr, AS_none,
9580 /*ModulePrivateLoc=*/SourceLocation(),
9581 MultiTemplateParamsArg(), Owned, IsDependent,
9582 SourceLocation(), false, TypeResult(),
9583 /*IsTypeSpecifier*/false,
9584 /*IsTemplateParamOrArg*/false);
9585 assert(!IsDependent && "explicit instantiation of dependent name not yet handled");
9590 TagDecl *Tag = cast<TagDecl>(TagD);
9591 assert(!Tag->isEnum() && "shouldn't see enumerations here");
9593 if (Tag->isInvalidDecl())
9596 CXXRecordDecl *Record = cast<CXXRecordDecl>(Tag);
9597 CXXRecordDecl *Pattern = Record->getInstantiatedFromMemberClass();
9599 Diag(TemplateLoc, diag::err_explicit_instantiation_nontemplate_type)
9600 << Context.getTypeDeclType(Record);
9601 Diag(Record->getLocation(), diag::note_nontemplate_decl_here);
9605 // C++0x [temp.explicit]p2:
9606 // If the explicit instantiation is for a class or member class, the
9607 // elaborated-type-specifier in the declaration shall include a
9608 // simple-template-id.
9610 // C++98 has the same restriction, just worded differently.
9611 if (!ScopeSpecifierHasTemplateId(SS))
9612 Diag(TemplateLoc, diag::ext_explicit_instantiation_without_qualified_id)
9613 << Record << SS.getRange();
9615 // C++0x [temp.explicit]p2:
9616 // There are two forms of explicit instantiation: an explicit instantiation
9617 // definition and an explicit instantiation declaration. An explicit
9618 // instantiation declaration begins with the extern keyword. [...]
9619 TemplateSpecializationKind TSK
9620 = ExternLoc.isInvalid()? TSK_ExplicitInstantiationDefinition
9621 : TSK_ExplicitInstantiationDeclaration;
9623 CheckExplicitInstantiation(*this, Record, NameLoc, true, TSK);
9625 // Verify that it is okay to explicitly instantiate here.
9626 CXXRecordDecl *PrevDecl
9627 = cast_or_null<CXXRecordDecl>(Record->getPreviousDecl());
9628 if (!PrevDecl && Record->getDefinition())
9631 MemberSpecializationInfo *MSInfo = PrevDecl->getMemberSpecializationInfo();
9632 bool HasNoEffect = false;
9633 assert(MSInfo && "No member specialization information?");
9634 if (CheckSpecializationInstantiationRedecl(TemplateLoc, TSK,
9636 MSInfo->getTemplateSpecializationKind(),
9637 MSInfo->getPointOfInstantiation(),
9644 CXXRecordDecl *RecordDef
9645 = cast_or_null<CXXRecordDecl>(Record->getDefinition());
9647 // C++ [temp.explicit]p3:
9648 // A definition of a member class of a class template shall be in scope
9649 // at the point of an explicit instantiation of the member class.
9651 = cast_or_null<CXXRecordDecl>(Pattern->getDefinition());
9653 Diag(TemplateLoc, diag::err_explicit_instantiation_undefined_member)
9654 << 0 << Record->getDeclName() << Record->getDeclContext();
9655 Diag(Pattern->getLocation(), diag::note_forward_declaration)
9659 if (InstantiateClass(NameLoc, Record, Def,
9660 getTemplateInstantiationArgs(Record),
9664 RecordDef = cast_or_null<CXXRecordDecl>(Record->getDefinition());
9670 // Instantiate all of the members of the class.
9671 InstantiateClassMembers(NameLoc, RecordDef,
9672 getTemplateInstantiationArgs(Record), TSK);
9674 if (TSK == TSK_ExplicitInstantiationDefinition)
9675 MarkVTableUsed(NameLoc, RecordDef, true);
9677 // FIXME: We don't have any representation for explicit instantiations of
9678 // member classes. Such a representation is not needed for compilation, but it
9679 // should be available for clients that want to see all of the declarations in
9684 DeclResult Sema::ActOnExplicitInstantiation(Scope *S,
9685 SourceLocation ExternLoc,
9686 SourceLocation TemplateLoc,
9688 // Explicit instantiations always require a name.
9689 // TODO: check if/when DNInfo should replace Name.
9690 DeclarationNameInfo NameInfo = GetNameForDeclarator(D);
9691 DeclarationName Name = NameInfo.getName();
9693 if (!D.isInvalidType())
9694 Diag(D.getDeclSpec().getBeginLoc(),
9695 diag::err_explicit_instantiation_requires_name)
9696 << D.getDeclSpec().getSourceRange() << D.getSourceRange();
9701 // The scope passed in may not be a decl scope. Zip up the scope tree until
9702 // we find one that is.
9703 while ((S->getFlags() & Scope::DeclScope) == 0 ||
9704 (S->getFlags() & Scope::TemplateParamScope) != 0)
9707 // Determine the type of the declaration.
9708 TypeSourceInfo *T = GetTypeForDeclarator(D, S);
9709 QualType R = T->getType();
9714 // A storage-class-specifier shall not be specified in [...] an explicit
9715 // instantiation (14.7.2) directive.
9716 if (D.getDeclSpec().getStorageClassSpec() == DeclSpec::SCS_typedef) {
9717 Diag(D.getIdentifierLoc(), diag::err_explicit_instantiation_of_typedef)
9720 } else if (D.getDeclSpec().getStorageClassSpec()
9721 != DeclSpec::SCS_unspecified) {
9722 // Complain about then remove the storage class specifier.
9723 Diag(D.getIdentifierLoc(), diag::err_explicit_instantiation_storage_class)
9724 << FixItHint::CreateRemoval(D.getDeclSpec().getStorageClassSpecLoc());
9726 D.getMutableDeclSpec().ClearStorageClassSpecs();
9729 // C++0x [temp.explicit]p1:
9730 // [...] An explicit instantiation of a function template shall not use the
9731 // inline or constexpr specifiers.
9732 // Presumably, this also applies to member functions of class templates as
9734 if (D.getDeclSpec().isInlineSpecified())
9735 Diag(D.getDeclSpec().getInlineSpecLoc(),
9736 getLangOpts().CPlusPlus11 ?
9737 diag::err_explicit_instantiation_inline :
9738 diag::warn_explicit_instantiation_inline_0x)
9739 << FixItHint::CreateRemoval(D.getDeclSpec().getInlineSpecLoc());
9740 if (D.getDeclSpec().hasConstexprSpecifier() && R->isFunctionType())
9741 // FIXME: Add a fix-it to remove the 'constexpr' and add a 'const' if one is
9742 // not already specified.
9743 Diag(D.getDeclSpec().getConstexprSpecLoc(),
9744 diag::err_explicit_instantiation_constexpr);
9746 // A deduction guide is not on the list of entities that can be explicitly
9748 if (Name.getNameKind() == DeclarationName::CXXDeductionGuideName) {
9749 Diag(D.getDeclSpec().getBeginLoc(), diag::err_deduction_guide_specialized)
9750 << /*explicit instantiation*/ 0;
9754 // C++0x [temp.explicit]p2:
9755 // There are two forms of explicit instantiation: an explicit instantiation
9756 // definition and an explicit instantiation declaration. An explicit
9757 // instantiation declaration begins with the extern keyword. [...]
9758 TemplateSpecializationKind TSK
9759 = ExternLoc.isInvalid()? TSK_ExplicitInstantiationDefinition
9760 : TSK_ExplicitInstantiationDeclaration;
9762 LookupResult Previous(*this, NameInfo, LookupOrdinaryName);
9763 LookupParsedName(Previous, S, &D.getCXXScopeSpec());
9765 if (!R->isFunctionType()) {
9766 // C++ [temp.explicit]p1:
9767 // A [...] static data member of a class template can be explicitly
9768 // instantiated from the member definition associated with its class
9770 // C++1y [temp.explicit]p1:
9771 // A [...] variable [...] template specialization can be explicitly
9772 // instantiated from its template.
9773 if (Previous.isAmbiguous())
9776 VarDecl *Prev = Previous.getAsSingle<VarDecl>();
9777 VarTemplateDecl *PrevTemplate = Previous.getAsSingle<VarTemplateDecl>();
9779 if (!PrevTemplate) {
9780 if (!Prev || !Prev->isStaticDataMember()) {
9781 // We expect to see a static data member here.
9782 Diag(D.getIdentifierLoc(), diag::err_explicit_instantiation_not_known)
9784 for (LookupResult::iterator P = Previous.begin(), PEnd = Previous.end();
9786 Diag((*P)->getLocation(), diag::note_explicit_instantiation_here);
9790 if (!Prev->getInstantiatedFromStaticDataMember()) {
9791 // FIXME: Check for explicit specialization?
9792 Diag(D.getIdentifierLoc(),
9793 diag::err_explicit_instantiation_data_member_not_instantiated)
9795 Diag(Prev->getLocation(), diag::note_explicit_instantiation_here);
9796 // FIXME: Can we provide a note showing where this was declared?
9800 // Explicitly instantiate a variable template.
9802 // C++1y [dcl.spec.auto]p6:
9803 // ... A program that uses auto or decltype(auto) in a context not
9804 // explicitly allowed in this section is ill-formed.
9806 // This includes auto-typed variable template instantiations.
9807 if (R->isUndeducedType()) {
9808 Diag(T->getTypeLoc().getBeginLoc(),
9809 diag::err_auto_not_allowed_var_inst);
9813 if (D.getName().getKind() != UnqualifiedIdKind::IK_TemplateId) {
9814 // C++1y [temp.explicit]p3:
9815 // If the explicit instantiation is for a variable, the unqualified-id
9816 // in the declaration shall be a template-id.
9817 Diag(D.getIdentifierLoc(),
9818 diag::err_explicit_instantiation_without_template_id)
9820 Diag(PrevTemplate->getLocation(),
9821 diag::note_explicit_instantiation_here);
9825 // Translate the parser's template argument list into our AST format.
9826 TemplateArgumentListInfo TemplateArgs =
9827 makeTemplateArgumentListInfo(*this, *D.getName().TemplateId);
9829 DeclResult Res = CheckVarTemplateId(PrevTemplate, TemplateLoc,
9830 D.getIdentifierLoc(), TemplateArgs);
9831 if (Res.isInvalid())
9834 // Ignore access control bits, we don't need them for redeclaration
9836 Prev = cast<VarDecl>(Res.get());
9839 // C++0x [temp.explicit]p2:
9840 // If the explicit instantiation is for a member function, a member class
9841 // or a static data member of a class template specialization, the name of
9842 // the class template specialization in the qualified-id for the member
9843 // name shall be a simple-template-id.
9845 // C++98 has the same restriction, just worded differently.
9847 // This does not apply to variable template specializations, where the
9848 // template-id is in the unqualified-id instead.
9849 if (!ScopeSpecifierHasTemplateId(D.getCXXScopeSpec()) && !PrevTemplate)
9850 Diag(D.getIdentifierLoc(),
9851 diag::ext_explicit_instantiation_without_qualified_id)
9852 << Prev << D.getCXXScopeSpec().getRange();
9854 CheckExplicitInstantiation(*this, Prev, D.getIdentifierLoc(), true, TSK);
9856 // Verify that it is okay to explicitly instantiate here.
9857 TemplateSpecializationKind PrevTSK = Prev->getTemplateSpecializationKind();
9858 SourceLocation POI = Prev->getPointOfInstantiation();
9859 bool HasNoEffect = false;
9860 if (CheckSpecializationInstantiationRedecl(D.getIdentifierLoc(), TSK, Prev,
9861 PrevTSK, POI, HasNoEffect))
9865 // Instantiate static data member or variable template.
9866 Prev->setTemplateSpecializationKind(TSK, D.getIdentifierLoc());
9867 // Merge attributes.
9868 ProcessDeclAttributeList(S, Prev, D.getDeclSpec().getAttributes());
9869 if (TSK == TSK_ExplicitInstantiationDefinition)
9870 InstantiateVariableDefinition(D.getIdentifierLoc(), Prev);
9873 // Check the new variable specialization against the parsed input.
9874 if (PrevTemplate && Prev && !Context.hasSameType(Prev->getType(), R)) {
9875 Diag(T->getTypeLoc().getBeginLoc(),
9876 diag::err_invalid_var_template_spec_type)
9877 << 0 << PrevTemplate << R << Prev->getType();
9878 Diag(PrevTemplate->getLocation(), diag::note_template_declared_here)
9879 << 2 << PrevTemplate->getDeclName();
9883 // FIXME: Create an ExplicitInstantiation node?
9884 return (Decl*) nullptr;
9887 // If the declarator is a template-id, translate the parser's template
9888 // argument list into our AST format.
9889 bool HasExplicitTemplateArgs = false;
9890 TemplateArgumentListInfo TemplateArgs;
9891 if (D.getName().getKind() == UnqualifiedIdKind::IK_TemplateId) {
9892 TemplateArgs = makeTemplateArgumentListInfo(*this, *D.getName().TemplateId);
9893 HasExplicitTemplateArgs = true;
9896 // C++ [temp.explicit]p1:
9897 // A [...] function [...] can be explicitly instantiated from its template.
9898 // A member function [...] of a class template can be explicitly
9899 // instantiated from the member definition associated with its class
9901 UnresolvedSet<8> TemplateMatches;
9902 FunctionDecl *NonTemplateMatch = nullptr;
9903 TemplateSpecCandidateSet FailedCandidates(D.getIdentifierLoc());
9904 for (LookupResult::iterator P = Previous.begin(), PEnd = Previous.end();
9906 NamedDecl *Prev = *P;
9907 if (!HasExplicitTemplateArgs) {
9908 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Prev)) {
9909 QualType Adjusted = adjustCCAndNoReturn(R, Method->getType(),
9910 /*AdjustExceptionSpec*/true);
9911 if (Context.hasSameUnqualifiedType(Method->getType(), Adjusted)) {
9912 if (Method->getPrimaryTemplate()) {
9913 TemplateMatches.addDecl(Method, P.getAccess());
9915 // FIXME: Can this assert ever happen? Needs a test.
9916 assert(!NonTemplateMatch && "Multiple NonTemplateMatches");
9917 NonTemplateMatch = Method;
9923 FunctionTemplateDecl *FunTmpl = dyn_cast<FunctionTemplateDecl>(Prev);
9927 TemplateDeductionInfo Info(FailedCandidates.getLocation());
9928 FunctionDecl *Specialization = nullptr;
9929 if (TemplateDeductionResult TDK
9930 = DeduceTemplateArguments(FunTmpl,
9931 (HasExplicitTemplateArgs ? &TemplateArgs
9933 R, Specialization, Info)) {
9934 // Keep track of almost-matches.
9935 FailedCandidates.addCandidate()
9936 .set(P.getPair(), FunTmpl->getTemplatedDecl(),
9937 MakeDeductionFailureInfo(Context, TDK, Info));
9942 // Target attributes are part of the cuda function signature, so
9943 // the cuda target of the instantiated function must match that of its
9944 // template. Given that C++ template deduction does not take
9945 // target attributes into account, we reject candidates here that
9946 // have a different target.
9947 if (LangOpts.CUDA &&
9948 IdentifyCUDATarget(Specialization,
9949 /* IgnoreImplicitHDAttr = */ true) !=
9950 IdentifyCUDATarget(D.getDeclSpec().getAttributes())) {
9951 FailedCandidates.addCandidate().set(
9952 P.getPair(), FunTmpl->getTemplatedDecl(),
9953 MakeDeductionFailureInfo(Context, TDK_CUDATargetMismatch, Info));
9957 TemplateMatches.addDecl(Specialization, P.getAccess());
9960 FunctionDecl *Specialization = NonTemplateMatch;
9961 if (!Specialization) {
9962 // Find the most specialized function template specialization.
9963 UnresolvedSetIterator Result = getMostSpecialized(
9964 TemplateMatches.begin(), TemplateMatches.end(), FailedCandidates,
9965 D.getIdentifierLoc(),
9966 PDiag(diag::err_explicit_instantiation_not_known) << Name,
9967 PDiag(diag::err_explicit_instantiation_ambiguous) << Name,
9968 PDiag(diag::note_explicit_instantiation_candidate));
9970 if (Result == TemplateMatches.end())
9973 // Ignore access control bits, we don't need them for redeclaration checking.
9974 Specialization = cast<FunctionDecl>(*Result);
9977 // C++11 [except.spec]p4
9978 // In an explicit instantiation an exception-specification may be specified,
9979 // but is not required.
9980 // If an exception-specification is specified in an explicit instantiation
9981 // directive, it shall be compatible with the exception-specifications of
9982 // other declarations of that function.
9983 if (auto *FPT = R->getAs<FunctionProtoType>())
9984 if (FPT->hasExceptionSpec()) {
9986 diag::err_mismatched_exception_spec_explicit_instantiation;
9987 if (getLangOpts().MicrosoftExt)
9988 DiagID = diag::ext_mismatched_exception_spec_explicit_instantiation;
9989 bool Result = CheckEquivalentExceptionSpec(
9990 PDiag(DiagID) << Specialization->getType(),
9991 PDiag(diag::note_explicit_instantiation_here),
9992 Specialization->getType()->getAs<FunctionProtoType>(),
9993 Specialization->getLocation(), FPT, D.getBeginLoc());
9994 // In Microsoft mode, mismatching exception specifications just cause a
9996 if (!getLangOpts().MicrosoftExt && Result)
10000 if (Specialization->getTemplateSpecializationKind() == TSK_Undeclared) {
10001 Diag(D.getIdentifierLoc(),
10002 diag::err_explicit_instantiation_member_function_not_instantiated)
10004 << (Specialization->getTemplateSpecializationKind() ==
10005 TSK_ExplicitSpecialization);
10006 Diag(Specialization->getLocation(), diag::note_explicit_instantiation_here);
10010 FunctionDecl *PrevDecl = Specialization->getPreviousDecl();
10011 if (!PrevDecl && Specialization->isThisDeclarationADefinition())
10012 PrevDecl = Specialization;
10015 bool HasNoEffect = false;
10016 if (CheckSpecializationInstantiationRedecl(D.getIdentifierLoc(), TSK,
10018 PrevDecl->getTemplateSpecializationKind(),
10019 PrevDecl->getPointOfInstantiation(),
10023 // FIXME: We may still want to build some representation of this
10024 // explicit specialization.
10026 return (Decl*) nullptr;
10029 // HACK: libc++ has a bug where it attempts to explicitly instantiate the
10031 // valarray<size_t>::valarray(size_t) and
10032 // valarray<size_t>::~valarray()
10033 // that it declared to have internal linkage with the internal_linkage
10034 // attribute. Ignore the explicit instantiation declaration in this case.
10035 if (Specialization->hasAttr<InternalLinkageAttr>() &&
10036 TSK == TSK_ExplicitInstantiationDeclaration) {
10037 if (auto *RD = dyn_cast<CXXRecordDecl>(Specialization->getDeclContext()))
10038 if (RD->getIdentifier() && RD->getIdentifier()->isStr("valarray") &&
10039 RD->isInStdNamespace())
10040 return (Decl*) nullptr;
10043 ProcessDeclAttributeList(S, Specialization, D.getDeclSpec().getAttributes());
10045 // In MSVC mode, dllimported explicit instantiation definitions are treated as
10046 // instantiation declarations.
10047 if (TSK == TSK_ExplicitInstantiationDefinition &&
10048 Specialization->hasAttr<DLLImportAttr>() &&
10049 Context.getTargetInfo().getCXXABI().isMicrosoft())
10050 TSK = TSK_ExplicitInstantiationDeclaration;
10052 Specialization->setTemplateSpecializationKind(TSK, D.getIdentifierLoc());
10054 if (Specialization->isDefined()) {
10055 // Let the ASTConsumer know that this function has been explicitly
10056 // instantiated now, and its linkage might have changed.
10057 Consumer.HandleTopLevelDecl(DeclGroupRef(Specialization));
10058 } else if (TSK == TSK_ExplicitInstantiationDefinition)
10059 InstantiateFunctionDefinition(D.getIdentifierLoc(), Specialization);
10061 // C++0x [temp.explicit]p2:
10062 // If the explicit instantiation is for a member function, a member class
10063 // or a static data member of a class template specialization, the name of
10064 // the class template specialization in the qualified-id for the member
10065 // name shall be a simple-template-id.
10067 // C++98 has the same restriction, just worded differently.
10068 FunctionTemplateDecl *FunTmpl = Specialization->getPrimaryTemplate();
10069 if (D.getName().getKind() != UnqualifiedIdKind::IK_TemplateId && !FunTmpl &&
10070 D.getCXXScopeSpec().isSet() &&
10071 !ScopeSpecifierHasTemplateId(D.getCXXScopeSpec()))
10072 Diag(D.getIdentifierLoc(),
10073 diag::ext_explicit_instantiation_without_qualified_id)
10074 << Specialization << D.getCXXScopeSpec().getRange();
10076 CheckExplicitInstantiation(
10078 FunTmpl ? (NamedDecl *)FunTmpl
10079 : Specialization->getInstantiatedFromMemberFunction(),
10080 D.getIdentifierLoc(), D.getCXXScopeSpec().isSet(), TSK);
10082 // FIXME: Create some kind of ExplicitInstantiationDecl here.
10083 return (Decl*) nullptr;
10087 Sema::ActOnDependentTag(Scope *S, unsigned TagSpec, TagUseKind TUK,
10088 const CXXScopeSpec &SS, IdentifierInfo *Name,
10089 SourceLocation TagLoc, SourceLocation NameLoc) {
10090 // This has to hold, because SS is expected to be defined.
10091 assert(Name && "Expected a name in a dependent tag");
10093 NestedNameSpecifier *NNS = SS.getScopeRep();
10097 TagTypeKind Kind = TypeWithKeyword::getTagTypeKindForTypeSpec(TagSpec);
10099 if (TUK == TUK_Declaration || TUK == TUK_Definition) {
10100 Diag(NameLoc, diag::err_dependent_tag_decl)
10101 << (TUK == TUK_Definition) << Kind << SS.getRange();
10105 // Create the resulting type.
10106 ElaboratedTypeKeyword Kwd = TypeWithKeyword::getKeywordForTagTypeKind(Kind);
10107 QualType Result = Context.getDependentNameType(Kwd, NNS, Name);
10109 // Create type-source location information for this type.
10110 TypeLocBuilder TLB;
10111 DependentNameTypeLoc TL = TLB.push<DependentNameTypeLoc>(Result);
10112 TL.setElaboratedKeywordLoc(TagLoc);
10113 TL.setQualifierLoc(SS.getWithLocInContext(Context));
10114 TL.setNameLoc(NameLoc);
10115 return CreateParsedType(Result, TLB.getTypeSourceInfo(Context, Result));
10119 Sema::ActOnTypenameType(Scope *S, SourceLocation TypenameLoc,
10120 const CXXScopeSpec &SS, const IdentifierInfo &II,
10121 SourceLocation IdLoc) {
10122 if (SS.isInvalid())
10125 if (TypenameLoc.isValid() && S && !S->getTemplateParamParent())
10127 getLangOpts().CPlusPlus11 ?
10128 diag::warn_cxx98_compat_typename_outside_of_template :
10129 diag::ext_typename_outside_of_template)
10130 << FixItHint::CreateRemoval(TypenameLoc);
10132 NestedNameSpecifierLoc QualifierLoc = SS.getWithLocInContext(Context);
10133 TypeSourceInfo *TSI = nullptr;
10134 QualType T = CheckTypenameType(TypenameLoc.isValid()? ETK_Typename : ETK_None,
10135 TypenameLoc, QualifierLoc, II, IdLoc, &TSI,
10136 /*DeducedTSTContext=*/true);
10139 return CreateParsedType(T, TSI);
10143 Sema::ActOnTypenameType(Scope *S,
10144 SourceLocation TypenameLoc,
10145 const CXXScopeSpec &SS,
10146 SourceLocation TemplateKWLoc,
10147 TemplateTy TemplateIn,
10148 IdentifierInfo *TemplateII,
10149 SourceLocation TemplateIILoc,
10150 SourceLocation LAngleLoc,
10151 ASTTemplateArgsPtr TemplateArgsIn,
10152 SourceLocation RAngleLoc) {
10153 if (TypenameLoc.isValid() && S && !S->getTemplateParamParent())
10155 getLangOpts().CPlusPlus11 ?
10156 diag::warn_cxx98_compat_typename_outside_of_template :
10157 diag::ext_typename_outside_of_template)
10158 << FixItHint::CreateRemoval(TypenameLoc);
10160 // Strangely, non-type results are not ignored by this lookup, so the
10161 // program is ill-formed if it finds an injected-class-name.
10162 if (TypenameLoc.isValid()) {
10164 dyn_cast_or_null<CXXRecordDecl>(computeDeclContext(SS, false));
10165 if (LookupRD && LookupRD->getIdentifier() == TemplateII) {
10166 Diag(TemplateIILoc,
10167 diag::ext_out_of_line_qualified_id_type_names_constructor)
10168 << TemplateII << 0 /*injected-class-name used as template name*/
10169 << (TemplateKWLoc.isValid() ? 1 : 0 /*'template'/'typename' keyword*/);
10173 // Translate the parser's template argument list in our AST format.
10174 TemplateArgumentListInfo TemplateArgs(LAngleLoc, RAngleLoc);
10175 translateTemplateArguments(TemplateArgsIn, TemplateArgs);
10177 TemplateName Template = TemplateIn.get();
10178 if (DependentTemplateName *DTN = Template.getAsDependentTemplateName()) {
10179 // Construct a dependent template specialization type.
10180 assert(DTN && "dependent template has non-dependent name?");
10181 assert(DTN->getQualifier() == SS.getScopeRep());
10182 QualType T = Context.getDependentTemplateSpecializationType(ETK_Typename,
10183 DTN->getQualifier(),
10184 DTN->getIdentifier(),
10187 // Create source-location information for this type.
10188 TypeLocBuilder Builder;
10189 DependentTemplateSpecializationTypeLoc SpecTL
10190 = Builder.push<DependentTemplateSpecializationTypeLoc>(T);
10191 SpecTL.setElaboratedKeywordLoc(TypenameLoc);
10192 SpecTL.setQualifierLoc(SS.getWithLocInContext(Context));
10193 SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
10194 SpecTL.setTemplateNameLoc(TemplateIILoc);
10195 SpecTL.setLAngleLoc(LAngleLoc);
10196 SpecTL.setRAngleLoc(RAngleLoc);
10197 for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I)
10198 SpecTL.setArgLocInfo(I, TemplateArgs[I].getLocInfo());
10199 return CreateParsedType(T, Builder.getTypeSourceInfo(Context, T));
10202 QualType T = CheckTemplateIdType(Template, TemplateIILoc, TemplateArgs);
10206 // Provide source-location information for the template specialization type.
10207 TypeLocBuilder Builder;
10208 TemplateSpecializationTypeLoc SpecTL
10209 = Builder.push<TemplateSpecializationTypeLoc>(T);
10210 SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
10211 SpecTL.setTemplateNameLoc(TemplateIILoc);
10212 SpecTL.setLAngleLoc(LAngleLoc);
10213 SpecTL.setRAngleLoc(RAngleLoc);
10214 for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I)
10215 SpecTL.setArgLocInfo(I, TemplateArgs[I].getLocInfo());
10217 T = Context.getElaboratedType(ETK_Typename, SS.getScopeRep(), T);
10218 ElaboratedTypeLoc TL = Builder.push<ElaboratedTypeLoc>(T);
10219 TL.setElaboratedKeywordLoc(TypenameLoc);
10220 TL.setQualifierLoc(SS.getWithLocInContext(Context));
10222 TypeSourceInfo *TSI = Builder.getTypeSourceInfo(Context, T);
10223 return CreateParsedType(T, TSI);
10227 /// Determine whether this failed name lookup should be treated as being
10228 /// disabled by a usage of std::enable_if.
10229 static bool isEnableIf(NestedNameSpecifierLoc NNS, const IdentifierInfo &II,
10230 SourceRange &CondRange, Expr *&Cond) {
10231 // We must be looking for a ::type...
10232 if (!II.isStr("type"))
10235 // ... within an explicitly-written template specialization...
10236 if (!NNS || !NNS.getNestedNameSpecifier()->getAsType())
10238 TypeLoc EnableIfTy = NNS.getTypeLoc();
10239 TemplateSpecializationTypeLoc EnableIfTSTLoc =
10240 EnableIfTy.getAs<TemplateSpecializationTypeLoc>();
10241 if (!EnableIfTSTLoc || EnableIfTSTLoc.getNumArgs() == 0)
10243 const TemplateSpecializationType *EnableIfTST = EnableIfTSTLoc.getTypePtr();
10245 // ... which names a complete class template declaration...
10246 const TemplateDecl *EnableIfDecl =
10247 EnableIfTST->getTemplateName().getAsTemplateDecl();
10248 if (!EnableIfDecl || EnableIfTST->isIncompleteType())
10251 // ... called "enable_if".
10252 const IdentifierInfo *EnableIfII =
10253 EnableIfDecl->getDeclName().getAsIdentifierInfo();
10254 if (!EnableIfII || !EnableIfII->isStr("enable_if"))
10257 // Assume the first template argument is the condition.
10258 CondRange = EnableIfTSTLoc.getArgLoc(0).getSourceRange();
10260 // Dig out the condition.
10262 if (EnableIfTSTLoc.getArgLoc(0).getArgument().getKind()
10263 != TemplateArgument::Expression)
10266 Cond = EnableIfTSTLoc.getArgLoc(0).getSourceExpression();
10268 // Ignore Boolean literals; they add no value.
10269 if (isa<CXXBoolLiteralExpr>(Cond->IgnoreParenCasts()))
10276 Sema::CheckTypenameType(ElaboratedTypeKeyword Keyword,
10277 SourceLocation KeywordLoc,
10278 NestedNameSpecifierLoc QualifierLoc,
10279 const IdentifierInfo &II,
10280 SourceLocation IILoc,
10281 TypeSourceInfo **TSI,
10282 bool DeducedTSTContext) {
10283 QualType T = CheckTypenameType(Keyword, KeywordLoc, QualifierLoc, II, IILoc,
10284 DeducedTSTContext);
10288 *TSI = Context.CreateTypeSourceInfo(T);
10289 if (isa<DependentNameType>(T)) {
10290 DependentNameTypeLoc TL =
10291 (*TSI)->getTypeLoc().castAs<DependentNameTypeLoc>();
10292 TL.setElaboratedKeywordLoc(KeywordLoc);
10293 TL.setQualifierLoc(QualifierLoc);
10294 TL.setNameLoc(IILoc);
10296 ElaboratedTypeLoc TL = (*TSI)->getTypeLoc().castAs<ElaboratedTypeLoc>();
10297 TL.setElaboratedKeywordLoc(KeywordLoc);
10298 TL.setQualifierLoc(QualifierLoc);
10299 TL.getNamedTypeLoc().castAs<TypeSpecTypeLoc>().setNameLoc(IILoc);
10304 /// Build the type that describes a C++ typename specifier,
10305 /// e.g., "typename T::type".
10307 Sema::CheckTypenameType(ElaboratedTypeKeyword Keyword,
10308 SourceLocation KeywordLoc,
10309 NestedNameSpecifierLoc QualifierLoc,
10310 const IdentifierInfo &II,
10311 SourceLocation IILoc, bool DeducedTSTContext) {
10313 SS.Adopt(QualifierLoc);
10315 DeclContext *Ctx = nullptr;
10316 if (QualifierLoc) {
10317 Ctx = computeDeclContext(SS);
10319 // If the nested-name-specifier is dependent and couldn't be
10320 // resolved to a type, build a typename type.
10321 assert(QualifierLoc.getNestedNameSpecifier()->isDependent());
10322 return Context.getDependentNameType(Keyword,
10323 QualifierLoc.getNestedNameSpecifier(),
10327 // If the nested-name-specifier refers to the current instantiation,
10328 // the "typename" keyword itself is superfluous. In C++03, the
10329 // program is actually ill-formed. However, DR 382 (in C++0x CD1)
10330 // allows such extraneous "typename" keywords, and we retroactively
10331 // apply this DR to C++03 code with only a warning. In any case we continue.
10333 if (RequireCompleteDeclContext(SS, Ctx))
10337 DeclarationName Name(&II);
10338 LookupResult Result(*this, Name, IILoc, LookupOrdinaryName);
10340 LookupQualifiedName(Result, Ctx, SS);
10342 LookupName(Result, CurScope);
10343 unsigned DiagID = 0;
10344 Decl *Referenced = nullptr;
10345 switch (Result.getResultKind()) {
10346 case LookupResult::NotFound: {
10347 // If we're looking up 'type' within a template named 'enable_if', produce
10348 // a more specific diagnostic.
10349 SourceRange CondRange;
10350 Expr *Cond = nullptr;
10351 if (Ctx && isEnableIf(QualifierLoc, II, CondRange, Cond)) {
10352 // If we have a condition, narrow it down to the specific failed
10356 std::string FailedDescription;
10357 std::tie(FailedCond, FailedDescription) =
10358 findFailedBooleanCondition(Cond);
10360 Diag(FailedCond->getExprLoc(),
10361 diag::err_typename_nested_not_found_requirement)
10362 << FailedDescription
10363 << FailedCond->getSourceRange();
10367 Diag(CondRange.getBegin(),
10368 diag::err_typename_nested_not_found_enable_if)
10369 << Ctx << CondRange;
10373 DiagID = Ctx ? diag::err_typename_nested_not_found
10374 : diag::err_unknown_typename;
10378 case LookupResult::FoundUnresolvedValue: {
10379 // We found a using declaration that is a value. Most likely, the using
10380 // declaration itself is meant to have the 'typename' keyword.
10381 SourceRange FullRange(KeywordLoc.isValid() ? KeywordLoc : SS.getBeginLoc(),
10383 Diag(IILoc, diag::err_typename_refers_to_using_value_decl)
10384 << Name << Ctx << FullRange;
10385 if (UnresolvedUsingValueDecl *Using
10386 = dyn_cast<UnresolvedUsingValueDecl>(Result.getRepresentativeDecl())){
10387 SourceLocation Loc = Using->getQualifierLoc().getBeginLoc();
10388 Diag(Loc, diag::note_using_value_decl_missing_typename)
10389 << FixItHint::CreateInsertion(Loc, "typename ");
10392 // Fall through to create a dependent typename type, from which we can recover
10396 case LookupResult::NotFoundInCurrentInstantiation:
10397 // Okay, it's a member of an unknown instantiation.
10398 return Context.getDependentNameType(Keyword,
10399 QualifierLoc.getNestedNameSpecifier(),
10402 case LookupResult::Found:
10403 if (TypeDecl *Type = dyn_cast<TypeDecl>(Result.getFoundDecl())) {
10404 // C++ [class.qual]p2:
10405 // In a lookup in which function names are not ignored and the
10406 // nested-name-specifier nominates a class C, if the name specified
10407 // after the nested-name-specifier, when looked up in C, is the
10408 // injected-class-name of C [...] then the name is instead considered
10409 // to name the constructor of class C.
10411 // Unlike in an elaborated-type-specifier, function names are not ignored
10412 // in typename-specifier lookup. However, they are ignored in all the
10413 // contexts where we form a typename type with no keyword (that is, in
10414 // mem-initializer-ids, base-specifiers, and elaborated-type-specifiers).
10416 // FIXME: That's not strictly true: mem-initializer-id lookup does not
10417 // ignore functions, but that appears to be an oversight.
10418 auto *LookupRD = dyn_cast_or_null<CXXRecordDecl>(Ctx);
10419 auto *FoundRD = dyn_cast<CXXRecordDecl>(Type);
10420 if (Keyword == ETK_Typename && LookupRD && FoundRD &&
10421 FoundRD->isInjectedClassName() &&
10422 declaresSameEntity(LookupRD, cast<Decl>(FoundRD->getParent())))
10423 Diag(IILoc, diag::ext_out_of_line_qualified_id_type_names_constructor)
10424 << &II << 1 << 0 /*'typename' keyword used*/;
10426 // We found a type. Build an ElaboratedType, since the
10427 // typename-specifier was just sugar.
10428 MarkAnyDeclReferenced(Type->getLocation(), Type, /*OdrUse=*/false);
10429 return Context.getElaboratedType(Keyword,
10430 QualifierLoc.getNestedNameSpecifier(),
10431 Context.getTypeDeclType(Type));
10434 // C++ [dcl.type.simple]p2:
10435 // A type-specifier of the form
10436 // typename[opt] nested-name-specifier[opt] template-name
10437 // is a placeholder for a deduced class type [...].
10438 if (getLangOpts().CPlusPlus17) {
10439 if (auto *TD = getAsTypeTemplateDecl(Result.getFoundDecl())) {
10440 if (!DeducedTSTContext) {
10441 QualType T(QualifierLoc
10442 ? QualifierLoc.getNestedNameSpecifier()->getAsType()
10445 Diag(IILoc, diag::err_dependent_deduced_tst)
10446 << (int)getTemplateNameKindForDiagnostics(TemplateName(TD)) << T;
10448 Diag(IILoc, diag::err_deduced_tst)
10449 << (int)getTemplateNameKindForDiagnostics(TemplateName(TD));
10450 Diag(TD->getLocation(), diag::note_template_decl_here);
10453 return Context.getElaboratedType(
10454 Keyword, QualifierLoc.getNestedNameSpecifier(),
10455 Context.getDeducedTemplateSpecializationType(TemplateName(TD),
10456 QualType(), false));
10460 DiagID = Ctx ? diag::err_typename_nested_not_type
10461 : diag::err_typename_not_type;
10462 Referenced = Result.getFoundDecl();
10465 case LookupResult::FoundOverloaded:
10466 DiagID = Ctx ? diag::err_typename_nested_not_type
10467 : diag::err_typename_not_type;
10468 Referenced = *Result.begin();
10471 case LookupResult::Ambiguous:
10475 // If we get here, it's because name lookup did not find a
10476 // type. Emit an appropriate diagnostic and return an error.
10477 SourceRange FullRange(KeywordLoc.isValid() ? KeywordLoc : SS.getBeginLoc(),
10480 Diag(IILoc, DiagID) << FullRange << Name << Ctx;
10482 Diag(IILoc, DiagID) << FullRange << Name;
10484 Diag(Referenced->getLocation(),
10485 Ctx ? diag::note_typename_member_refers_here
10486 : diag::note_typename_refers_here)
10492 // See Sema::RebuildTypeInCurrentInstantiation
10493 class CurrentInstantiationRebuilder
10494 : public TreeTransform<CurrentInstantiationRebuilder> {
10495 SourceLocation Loc;
10496 DeclarationName Entity;
10499 typedef TreeTransform<CurrentInstantiationRebuilder> inherited;
10501 CurrentInstantiationRebuilder(Sema &SemaRef,
10502 SourceLocation Loc,
10503 DeclarationName Entity)
10504 : TreeTransform<CurrentInstantiationRebuilder>(SemaRef),
10505 Loc(Loc), Entity(Entity) { }
10507 /// Determine whether the given type \p T has already been
10510 /// For the purposes of type reconstruction, a type has already been
10511 /// transformed if it is NULL or if it is not dependent.
10512 bool AlreadyTransformed(QualType T) {
10513 return T.isNull() || !T->isDependentType();
10516 /// Returns the location of the entity whose type is being
10518 SourceLocation getBaseLocation() { return Loc; }
10520 /// Returns the name of the entity whose type is being rebuilt.
10521 DeclarationName getBaseEntity() { return Entity; }
10523 /// Sets the "base" location and entity when that
10524 /// information is known based on another transformation.
10525 void setBase(SourceLocation Loc, DeclarationName Entity) {
10527 this->Entity = Entity;
10530 ExprResult TransformLambdaExpr(LambdaExpr *E) {
10531 // Lambdas never need to be transformed.
10535 } // end anonymous namespace
10537 /// Rebuilds a type within the context of the current instantiation.
10539 /// The type \p T is part of the type of an out-of-line member definition of
10540 /// a class template (or class template partial specialization) that was parsed
10541 /// and constructed before we entered the scope of the class template (or
10542 /// partial specialization thereof). This routine will rebuild that type now
10543 /// that we have entered the declarator's scope, which may produce different
10544 /// canonical types, e.g.,
10547 /// template<typename T>
10549 /// typedef T* pointer;
10550 /// pointer data();
10553 /// template<typename T>
10554 /// typename X<T>::pointer X<T>::data() { ... }
10557 /// Here, the type "typename X<T>::pointer" will be created as a DependentNameType,
10558 /// since we do not know that we can look into X<T> when we parsed the type.
10559 /// This function will rebuild the type, performing the lookup of "pointer"
10560 /// in X<T> and returning an ElaboratedType whose canonical type is the same
10561 /// as the canonical type of T*, allowing the return types of the out-of-line
10562 /// definition and the declaration to match.
10563 TypeSourceInfo *Sema::RebuildTypeInCurrentInstantiation(TypeSourceInfo *T,
10564 SourceLocation Loc,
10565 DeclarationName Name) {
10566 if (!T || !T->getType()->isDependentType())
10569 CurrentInstantiationRebuilder Rebuilder(*this, Loc, Name);
10570 return Rebuilder.TransformType(T);
10573 ExprResult Sema::RebuildExprInCurrentInstantiation(Expr *E) {
10574 CurrentInstantiationRebuilder Rebuilder(*this, E->getExprLoc(),
10575 DeclarationName());
10576 return Rebuilder.TransformExpr(E);
10579 bool Sema::RebuildNestedNameSpecifierInCurrentInstantiation(CXXScopeSpec &SS) {
10580 if (SS.isInvalid())
10583 NestedNameSpecifierLoc QualifierLoc = SS.getWithLocInContext(Context);
10584 CurrentInstantiationRebuilder Rebuilder(*this, SS.getRange().getBegin(),
10585 DeclarationName());
10586 NestedNameSpecifierLoc Rebuilt
10587 = Rebuilder.TransformNestedNameSpecifierLoc(QualifierLoc);
10595 /// Rebuild the template parameters now that we know we're in a current
10597 bool Sema::RebuildTemplateParamsInCurrentInstantiation(
10598 TemplateParameterList *Params) {
10599 for (unsigned I = 0, N = Params->size(); I != N; ++I) {
10600 Decl *Param = Params->getParam(I);
10602 // There is nothing to rebuild in a type parameter.
10603 if (isa<TemplateTypeParmDecl>(Param))
10606 // Rebuild the template parameter list of a template template parameter.
10607 if (TemplateTemplateParmDecl *TTP
10608 = dyn_cast<TemplateTemplateParmDecl>(Param)) {
10609 if (RebuildTemplateParamsInCurrentInstantiation(
10610 TTP->getTemplateParameters()))
10616 // Rebuild the type of a non-type template parameter.
10617 NonTypeTemplateParmDecl *NTTP = cast<NonTypeTemplateParmDecl>(Param);
10618 TypeSourceInfo *NewTSI
10619 = RebuildTypeInCurrentInstantiation(NTTP->getTypeSourceInfo(),
10620 NTTP->getLocation(),
10621 NTTP->getDeclName());
10625 if (NewTSI->getType()->isUndeducedType()) {
10626 // C++17 [temp.dep.expr]p3:
10627 // An id-expression is type-dependent if it contains
10628 // - an identifier associated by name lookup with a non-type
10629 // template-parameter declared with a type that contains a
10630 // placeholder type (7.1.7.4),
10631 NewTSI = SubstAutoTypeSourceInfo(NewTSI, Context.DependentTy);
10634 if (NewTSI != NTTP->getTypeSourceInfo()) {
10635 NTTP->setTypeSourceInfo(NewTSI);
10636 NTTP->setType(NewTSI->getType());
10643 /// Produces a formatted string that describes the binding of
10644 /// template parameters to template arguments.
10646 Sema::getTemplateArgumentBindingsText(const TemplateParameterList *Params,
10647 const TemplateArgumentList &Args) {
10648 return getTemplateArgumentBindingsText(Params, Args.data(), Args.size());
10652 Sema::getTemplateArgumentBindingsText(const TemplateParameterList *Params,
10653 const TemplateArgument *Args,
10654 unsigned NumArgs) {
10655 SmallString<128> Str;
10656 llvm::raw_svector_ostream Out(Str);
10658 if (!Params || Params->size() == 0 || NumArgs == 0)
10659 return std::string();
10661 for (unsigned I = 0, N = Params->size(); I != N; ++I) {
10670 if (const IdentifierInfo *Id = Params->getParam(I)->getIdentifier()) {
10671 Out << Id->getName();
10677 Args[I].print(getPrintingPolicy(), Out);
10684 void Sema::MarkAsLateParsedTemplate(FunctionDecl *FD, Decl *FnD,
10685 CachedTokens &Toks) {
10689 auto LPT = std::make_unique<LateParsedTemplate>();
10691 // Take tokens to avoid allocations
10692 LPT->Toks.swap(Toks);
10694 LateParsedTemplateMap.insert(std::make_pair(FD, std::move(LPT)));
10696 FD->setLateTemplateParsed(true);
10699 void Sema::UnmarkAsLateParsedTemplate(FunctionDecl *FD) {
10702 FD->setLateTemplateParsed(false);
10705 bool Sema::IsInsideALocalClassWithinATemplateFunction() {
10706 DeclContext *DC = CurContext;
10709 if (CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(CurContext)) {
10710 const FunctionDecl *FD = RD->isLocalClass();
10711 return (FD && FD->getTemplatedKind() != FunctionDecl::TK_NonTemplate);
10712 } else if (DC->isTranslationUnit() || DC->isNamespace())
10715 DC = DC->getParent();
10721 /// Walk the path from which a declaration was instantiated, and check
10722 /// that every explicit specialization along that path is visible. This enforces
10723 /// C++ [temp.expl.spec]/6:
10725 /// If a template, a member template or a member of a class template is
10726 /// explicitly specialized then that specialization shall be declared before
10727 /// the first use of that specialization that would cause an implicit
10728 /// instantiation to take place, in every translation unit in which such a
10729 /// use occurs; no diagnostic is required.
10731 /// and also C++ [temp.class.spec]/1:
10733 /// A partial specialization shall be declared before the first use of a
10734 /// class template specialization that would make use of the partial
10735 /// specialization as the result of an implicit or explicit instantiation
10736 /// in every translation unit in which such a use occurs; no diagnostic is
10738 class ExplicitSpecializationVisibilityChecker {
10740 SourceLocation Loc;
10741 llvm::SmallVector<Module *, 8> Modules;
10744 ExplicitSpecializationVisibilityChecker(Sema &S, SourceLocation Loc)
10745 : S(S), Loc(Loc) {}
10747 void check(NamedDecl *ND) {
10748 if (auto *FD = dyn_cast<FunctionDecl>(ND))
10749 return checkImpl(FD);
10750 if (auto *RD = dyn_cast<CXXRecordDecl>(ND))
10751 return checkImpl(RD);
10752 if (auto *VD = dyn_cast<VarDecl>(ND))
10753 return checkImpl(VD);
10754 if (auto *ED = dyn_cast<EnumDecl>(ND))
10755 return checkImpl(ED);
10759 void diagnose(NamedDecl *D, bool IsPartialSpec) {
10760 auto Kind = IsPartialSpec ? Sema::MissingImportKind::PartialSpecialization
10761 : Sema::MissingImportKind::ExplicitSpecialization;
10762 const bool Recover = true;
10764 // If we got a custom set of modules (because only a subset of the
10765 // declarations are interesting), use them, otherwise let
10766 // diagnoseMissingImport intelligently pick some.
10767 if (Modules.empty())
10768 S.diagnoseMissingImport(Loc, D, Kind, Recover);
10770 S.diagnoseMissingImport(Loc, D, D->getLocation(), Modules, Kind, Recover);
10773 // Check a specific declaration. There are three problematic cases:
10775 // 1) The declaration is an explicit specialization of a template
10777 // 2) The declaration is an explicit specialization of a member of an
10778 // templated class.
10779 // 3) The declaration is an instantiation of a template, and that template
10780 // is an explicit specialization of a member of a templated class.
10782 // We don't need to go any deeper than that, as the instantiation of the
10783 // surrounding class / etc is not triggered by whatever triggered this
10784 // instantiation, and thus should be checked elsewhere.
10785 template<typename SpecDecl>
10786 void checkImpl(SpecDecl *Spec) {
10787 bool IsHiddenExplicitSpecialization = false;
10788 if (Spec->getTemplateSpecializationKind() == TSK_ExplicitSpecialization) {
10789 IsHiddenExplicitSpecialization =
10790 Spec->getMemberSpecializationInfo()
10791 ? !S.hasVisibleMemberSpecialization(Spec, &Modules)
10792 : !S.hasVisibleExplicitSpecialization(Spec, &Modules);
10794 checkInstantiated(Spec);
10797 if (IsHiddenExplicitSpecialization)
10798 diagnose(Spec->getMostRecentDecl(), false);
10801 void checkInstantiated(FunctionDecl *FD) {
10802 if (auto *TD = FD->getPrimaryTemplate())
10806 void checkInstantiated(CXXRecordDecl *RD) {
10807 auto *SD = dyn_cast<ClassTemplateSpecializationDecl>(RD);
10811 auto From = SD->getSpecializedTemplateOrPartial();
10812 if (auto *TD = From.dyn_cast<ClassTemplateDecl *>())
10814 else if (auto *TD =
10815 From.dyn_cast<ClassTemplatePartialSpecializationDecl *>()) {
10816 if (!S.hasVisibleDeclaration(TD))
10817 diagnose(TD, true);
10822 void checkInstantiated(VarDecl *RD) {
10823 auto *SD = dyn_cast<VarTemplateSpecializationDecl>(RD);
10827 auto From = SD->getSpecializedTemplateOrPartial();
10828 if (auto *TD = From.dyn_cast<VarTemplateDecl *>())
10830 else if (auto *TD =
10831 From.dyn_cast<VarTemplatePartialSpecializationDecl *>()) {
10832 if (!S.hasVisibleDeclaration(TD))
10833 diagnose(TD, true);
10838 void checkInstantiated(EnumDecl *FD) {}
10840 template<typename TemplDecl>
10841 void checkTemplate(TemplDecl *TD) {
10842 if (TD->isMemberSpecialization()) {
10843 if (!S.hasVisibleMemberSpecialization(TD, &Modules))
10844 diagnose(TD->getMostRecentDecl(), false);
10848 } // end anonymous namespace
10850 void Sema::checkSpecializationVisibility(SourceLocation Loc, NamedDecl *Spec) {
10851 if (!getLangOpts().Modules)
10854 ExplicitSpecializationVisibilityChecker(*this, Loc).check(Spec);
10857 /// Check whether a template partial specialization that we've discovered
10858 /// is hidden, and produce suitable diagnostics if so.
10859 void Sema::checkPartialSpecializationVisibility(SourceLocation Loc,
10861 llvm::SmallVector<Module *, 8> Modules;
10862 if (!hasVisibleDeclaration(Spec, &Modules))
10863 diagnoseMissingImport(Loc, Spec, Spec->getLocation(), Modules,
10864 MissingImportKind::PartialSpecialization,