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) {
3821 return TypeResult(true);
3823 TemplateName Template = TemplateD.get();
3825 // Translate the parser's template argument list in our AST format.
3826 TemplateArgumentListInfo TemplateArgs(LAngleLoc, RAngleLoc);
3827 translateTemplateArguments(TemplateArgsIn, TemplateArgs);
3829 // Determine the tag kind
3830 TagTypeKind TagKind = TypeWithKeyword::getTagTypeKindForTypeSpec(TagSpec);
3831 ElaboratedTypeKeyword Keyword
3832 = TypeWithKeyword::getKeywordForTagTypeKind(TagKind);
3834 if (DependentTemplateName *DTN = Template.getAsDependentTemplateName()) {
3835 QualType T = Context.getDependentTemplateSpecializationType(Keyword,
3836 DTN->getQualifier(),
3837 DTN->getIdentifier(),
3840 // Build type-source information.
3842 DependentTemplateSpecializationTypeLoc SpecTL
3843 = TLB.push<DependentTemplateSpecializationTypeLoc>(T);
3844 SpecTL.setElaboratedKeywordLoc(TagLoc);
3845 SpecTL.setQualifierLoc(SS.getWithLocInContext(Context));
3846 SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
3847 SpecTL.setTemplateNameLoc(TemplateLoc);
3848 SpecTL.setLAngleLoc(LAngleLoc);
3849 SpecTL.setRAngleLoc(RAngleLoc);
3850 for (unsigned I = 0, N = SpecTL.getNumArgs(); I != N; ++I)
3851 SpecTL.setArgLocInfo(I, TemplateArgs[I].getLocInfo());
3852 return CreateParsedType(T, TLB.getTypeSourceInfo(Context, T));
3855 if (TypeAliasTemplateDecl *TAT =
3856 dyn_cast_or_null<TypeAliasTemplateDecl>(Template.getAsTemplateDecl())) {
3857 // C++0x [dcl.type.elab]p2:
3858 // If the identifier resolves to a typedef-name or the simple-template-id
3859 // resolves to an alias template specialization, the
3860 // elaborated-type-specifier is ill-formed.
3861 Diag(TemplateLoc, diag::err_tag_reference_non_tag)
3862 << TAT << NTK_TypeAliasTemplate << TagKind;
3863 Diag(TAT->getLocation(), diag::note_declared_at);
3866 QualType Result = CheckTemplateIdType(Template, TemplateLoc, TemplateArgs);
3867 if (Result.isNull())
3868 return TypeResult(true);
3870 // Check the tag kind
3871 if (const RecordType *RT = Result->getAs<RecordType>()) {
3872 RecordDecl *D = RT->getDecl();
3874 IdentifierInfo *Id = D->getIdentifier();
3875 assert(Id && "templated class must have an identifier");
3877 if (!isAcceptableTagRedeclaration(D, TagKind, TUK == TUK_Definition,
3879 Diag(TagLoc, diag::err_use_with_wrong_tag)
3881 << FixItHint::CreateReplacement(SourceRange(TagLoc), D->getKindName());
3882 Diag(D->getLocation(), diag::note_previous_use);
3886 // Provide source-location information for the template specialization.
3888 TemplateSpecializationTypeLoc SpecTL
3889 = TLB.push<TemplateSpecializationTypeLoc>(Result);
3890 SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
3891 SpecTL.setTemplateNameLoc(TemplateLoc);
3892 SpecTL.setLAngleLoc(LAngleLoc);
3893 SpecTL.setRAngleLoc(RAngleLoc);
3894 for (unsigned i = 0, e = SpecTL.getNumArgs(); i != e; ++i)
3895 SpecTL.setArgLocInfo(i, TemplateArgs[i].getLocInfo());
3897 // Construct an elaborated type containing the nested-name-specifier (if any)
3899 Result = Context.getElaboratedType(Keyword, SS.getScopeRep(), Result);
3900 ElaboratedTypeLoc ElabTL = TLB.push<ElaboratedTypeLoc>(Result);
3901 ElabTL.setElaboratedKeywordLoc(TagLoc);
3902 ElabTL.setQualifierLoc(SS.getWithLocInContext(Context));
3903 return CreateParsedType(Result, TLB.getTypeSourceInfo(Context, Result));
3906 static bool CheckTemplateSpecializationScope(Sema &S, NamedDecl *Specialized,
3907 NamedDecl *PrevDecl,
3909 bool IsPartialSpecialization);
3911 static TemplateSpecializationKind getTemplateSpecializationKind(Decl *D);
3913 static bool isTemplateArgumentTemplateParameter(
3914 const TemplateArgument &Arg, unsigned Depth, unsigned Index) {
3915 switch (Arg.getKind()) {
3916 case TemplateArgument::Null:
3917 case TemplateArgument::NullPtr:
3918 case TemplateArgument::Integral:
3919 case TemplateArgument::Declaration:
3920 case TemplateArgument::Pack:
3921 case TemplateArgument::TemplateExpansion:
3924 case TemplateArgument::Type: {
3925 QualType Type = Arg.getAsType();
3926 const TemplateTypeParmType *TPT =
3927 Arg.getAsType()->getAs<TemplateTypeParmType>();
3928 return TPT && !Type.hasQualifiers() &&
3929 TPT->getDepth() == Depth && TPT->getIndex() == Index;
3932 case TemplateArgument::Expression: {
3933 DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Arg.getAsExpr());
3934 if (!DRE || !DRE->getDecl())
3936 const NonTypeTemplateParmDecl *NTTP =
3937 dyn_cast<NonTypeTemplateParmDecl>(DRE->getDecl());
3938 return NTTP && NTTP->getDepth() == Depth && NTTP->getIndex() == Index;
3941 case TemplateArgument::Template:
3942 const TemplateTemplateParmDecl *TTP =
3943 dyn_cast_or_null<TemplateTemplateParmDecl>(
3944 Arg.getAsTemplateOrTemplatePattern().getAsTemplateDecl());
3945 return TTP && TTP->getDepth() == Depth && TTP->getIndex() == Index;
3947 llvm_unreachable("unexpected kind of template argument");
3950 static bool isSameAsPrimaryTemplate(TemplateParameterList *Params,
3951 ArrayRef<TemplateArgument> Args) {
3952 if (Params->size() != Args.size())
3955 unsigned Depth = Params->getDepth();
3957 for (unsigned I = 0, N = Args.size(); I != N; ++I) {
3958 TemplateArgument Arg = Args[I];
3960 // If the parameter is a pack expansion, the argument must be a pack
3961 // whose only element is a pack expansion.
3962 if (Params->getParam(I)->isParameterPack()) {
3963 if (Arg.getKind() != TemplateArgument::Pack || Arg.pack_size() != 1 ||
3964 !Arg.pack_begin()->isPackExpansion())
3966 Arg = Arg.pack_begin()->getPackExpansionPattern();
3969 if (!isTemplateArgumentTemplateParameter(Arg, Depth, I))
3976 template<typename PartialSpecDecl>
3977 static void checkMoreSpecializedThanPrimary(Sema &S, PartialSpecDecl *Partial) {
3978 if (Partial->getDeclContext()->isDependentContext())
3981 // FIXME: Get the TDK from deduction in order to provide better diagnostics
3982 // for non-substitution-failure issues?
3983 TemplateDeductionInfo Info(Partial->getLocation());
3984 if (S.isMoreSpecializedThanPrimary(Partial, Info))
3987 auto *Template = Partial->getSpecializedTemplate();
3988 S.Diag(Partial->getLocation(),
3989 diag::ext_partial_spec_not_more_specialized_than_primary)
3990 << isa<VarTemplateDecl>(Template);
3992 if (Info.hasSFINAEDiagnostic()) {
3993 PartialDiagnosticAt Diag = {SourceLocation(),
3994 PartialDiagnostic::NullDiagnostic()};
3995 Info.takeSFINAEDiagnostic(Diag);
3996 SmallString<128> SFINAEArgString;
3997 Diag.second.EmitToString(S.getDiagnostics(), SFINAEArgString);
3999 diag::note_partial_spec_not_more_specialized_than_primary)
4003 S.Diag(Template->getLocation(), diag::note_template_decl_here);
4004 SmallVector<const Expr *, 3> PartialAC, TemplateAC;
4005 Template->getAssociatedConstraints(TemplateAC);
4006 Partial->getAssociatedConstraints(PartialAC);
4007 S.MaybeEmitAmbiguousAtomicConstraintsDiagnostic(Partial, PartialAC, Template,
4012 noteNonDeducibleParameters(Sema &S, TemplateParameterList *TemplateParams,
4013 const llvm::SmallBitVector &DeducibleParams) {
4014 for (unsigned I = 0, N = DeducibleParams.size(); I != N; ++I) {
4015 if (!DeducibleParams[I]) {
4016 NamedDecl *Param = TemplateParams->getParam(I);
4017 if (Param->getDeclName())
4018 S.Diag(Param->getLocation(), diag::note_non_deducible_parameter)
4019 << Param->getDeclName();
4021 S.Diag(Param->getLocation(), diag::note_non_deducible_parameter)
4028 template<typename PartialSpecDecl>
4029 static void checkTemplatePartialSpecialization(Sema &S,
4030 PartialSpecDecl *Partial) {
4031 // C++1z [temp.class.spec]p8: (DR1495)
4032 // - The specialization shall be more specialized than the primary
4033 // template (14.5.5.2).
4034 checkMoreSpecializedThanPrimary(S, Partial);
4036 // C++ [temp.class.spec]p8: (DR1315)
4037 // - Each template-parameter shall appear at least once in the
4038 // template-id outside a non-deduced context.
4039 // C++1z [temp.class.spec.match]p3 (P0127R2)
4040 // If the template arguments of a partial specialization cannot be
4041 // deduced because of the structure of its template-parameter-list
4042 // and the template-id, the program is ill-formed.
4043 auto *TemplateParams = Partial->getTemplateParameters();
4044 llvm::SmallBitVector DeducibleParams(TemplateParams->size());
4045 S.MarkUsedTemplateParameters(Partial->getTemplateArgs(), true,
4046 TemplateParams->getDepth(), DeducibleParams);
4048 if (!DeducibleParams.all()) {
4049 unsigned NumNonDeducible = DeducibleParams.size() - DeducibleParams.count();
4050 S.Diag(Partial->getLocation(), diag::ext_partial_specs_not_deducible)
4051 << isa<VarTemplatePartialSpecializationDecl>(Partial)
4052 << (NumNonDeducible > 1)
4053 << SourceRange(Partial->getLocation(),
4054 Partial->getTemplateArgsAsWritten()->RAngleLoc);
4055 noteNonDeducibleParameters(S, TemplateParams, DeducibleParams);
4059 void Sema::CheckTemplatePartialSpecialization(
4060 ClassTemplatePartialSpecializationDecl *Partial) {
4061 checkTemplatePartialSpecialization(*this, Partial);
4064 void Sema::CheckTemplatePartialSpecialization(
4065 VarTemplatePartialSpecializationDecl *Partial) {
4066 checkTemplatePartialSpecialization(*this, Partial);
4069 void Sema::CheckDeductionGuideTemplate(FunctionTemplateDecl *TD) {
4070 // C++1z [temp.param]p11:
4071 // A template parameter of a deduction guide template that does not have a
4072 // default-argument shall be deducible from the parameter-type-list of the
4073 // deduction guide template.
4074 auto *TemplateParams = TD->getTemplateParameters();
4075 llvm::SmallBitVector DeducibleParams(TemplateParams->size());
4076 MarkDeducedTemplateParameters(TD, DeducibleParams);
4077 for (unsigned I = 0; I != TemplateParams->size(); ++I) {
4078 // A parameter pack is deducible (to an empty pack).
4079 auto *Param = TemplateParams->getParam(I);
4080 if (Param->isParameterPack() || hasVisibleDefaultArgument(Param))
4081 DeducibleParams[I] = true;
4084 if (!DeducibleParams.all()) {
4085 unsigned NumNonDeducible = DeducibleParams.size() - DeducibleParams.count();
4086 Diag(TD->getLocation(), diag::err_deduction_guide_template_not_deducible)
4087 << (NumNonDeducible > 1);
4088 noteNonDeducibleParameters(*this, TemplateParams, DeducibleParams);
4092 DeclResult Sema::ActOnVarTemplateSpecialization(
4093 Scope *S, Declarator &D, TypeSourceInfo *DI, SourceLocation TemplateKWLoc,
4094 TemplateParameterList *TemplateParams, StorageClass SC,
4095 bool IsPartialSpecialization) {
4096 // D must be variable template id.
4097 assert(D.getName().getKind() == UnqualifiedIdKind::IK_TemplateId &&
4098 "Variable template specialization is declared with a template it.");
4100 TemplateIdAnnotation *TemplateId = D.getName().TemplateId;
4101 TemplateArgumentListInfo TemplateArgs =
4102 makeTemplateArgumentListInfo(*this, *TemplateId);
4103 SourceLocation TemplateNameLoc = D.getIdentifierLoc();
4104 SourceLocation LAngleLoc = TemplateId->LAngleLoc;
4105 SourceLocation RAngleLoc = TemplateId->RAngleLoc;
4107 TemplateName Name = TemplateId->Template.get();
4109 // The template-id must name a variable template.
4110 VarTemplateDecl *VarTemplate =
4111 dyn_cast_or_null<VarTemplateDecl>(Name.getAsTemplateDecl());
4113 NamedDecl *FnTemplate;
4114 if (auto *OTS = Name.getAsOverloadedTemplate())
4115 FnTemplate = *OTS->begin();
4117 FnTemplate = dyn_cast_or_null<FunctionTemplateDecl>(Name.getAsTemplateDecl());
4119 return Diag(D.getIdentifierLoc(), diag::err_var_spec_no_template_but_method)
4120 << FnTemplate->getDeclName();
4121 return Diag(D.getIdentifierLoc(), diag::err_var_spec_no_template)
4122 << IsPartialSpecialization;
4125 // Check for unexpanded parameter packs in any of the template arguments.
4126 for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I)
4127 if (DiagnoseUnexpandedParameterPack(TemplateArgs[I],
4128 UPPC_PartialSpecialization))
4131 // Check that the template argument list is well-formed for this
4133 SmallVector<TemplateArgument, 4> Converted;
4134 if (CheckTemplateArgumentList(VarTemplate, TemplateNameLoc, TemplateArgs,
4136 /*UpdateArgsWithConversion=*/true))
4139 // Find the variable template (partial) specialization declaration that
4140 // corresponds to these arguments.
4141 if (IsPartialSpecialization) {
4142 if (CheckTemplatePartialSpecializationArgs(TemplateNameLoc, VarTemplate,
4143 TemplateArgs.size(), Converted))
4146 // FIXME: Move these checks to CheckTemplatePartialSpecializationArgs so we
4147 // also do them during instantiation.
4148 bool InstantiationDependent;
4149 if (!Name.isDependent() &&
4150 !TemplateSpecializationType::anyDependentTemplateArguments(
4151 TemplateArgs.arguments(),
4152 InstantiationDependent)) {
4153 Diag(TemplateNameLoc, diag::err_partial_spec_fully_specialized)
4154 << VarTemplate->getDeclName();
4155 IsPartialSpecialization = false;
4158 if (isSameAsPrimaryTemplate(VarTemplate->getTemplateParameters(),
4160 (!Context.getLangOpts().CPlusPlus2a ||
4161 !TemplateParams->hasAssociatedConstraints())) {
4162 // C++ [temp.class.spec]p9b3:
4164 // -- The argument list of the specialization shall not be identical
4165 // to the implicit argument list of the primary template.
4166 Diag(TemplateNameLoc, diag::err_partial_spec_args_match_primary_template)
4167 << /*variable template*/ 1
4168 << /*is definition*/(SC != SC_Extern && !CurContext->isRecord())
4169 << FixItHint::CreateRemoval(SourceRange(LAngleLoc, RAngleLoc));
4170 // FIXME: Recover from this by treating the declaration as a redeclaration
4171 // of the primary template.
4176 void *InsertPos = nullptr;
4177 VarTemplateSpecializationDecl *PrevDecl = nullptr;
4179 if (IsPartialSpecialization)
4180 PrevDecl = VarTemplate->findPartialSpecialization(Converted, TemplateParams,
4183 PrevDecl = VarTemplate->findSpecialization(Converted, InsertPos);
4185 VarTemplateSpecializationDecl *Specialization = nullptr;
4187 // Check whether we can declare a variable template specialization in
4188 // the current scope.
4189 if (CheckTemplateSpecializationScope(*this, VarTemplate, PrevDecl,
4191 IsPartialSpecialization))
4194 if (PrevDecl && PrevDecl->getSpecializationKind() == TSK_Undeclared) {
4195 // Since the only prior variable template specialization with these
4196 // arguments was referenced but not declared, reuse that
4197 // declaration node as our own, updating its source location and
4198 // the list of outer template parameters to reflect our new declaration.
4199 Specialization = PrevDecl;
4200 Specialization->setLocation(TemplateNameLoc);
4202 } else if (IsPartialSpecialization) {
4203 // Create a new class template partial specialization declaration node.
4204 VarTemplatePartialSpecializationDecl *PrevPartial =
4205 cast_or_null<VarTemplatePartialSpecializationDecl>(PrevDecl);
4206 VarTemplatePartialSpecializationDecl *Partial =
4207 VarTemplatePartialSpecializationDecl::Create(
4208 Context, VarTemplate->getDeclContext(), TemplateKWLoc,
4209 TemplateNameLoc, TemplateParams, VarTemplate, DI->getType(), DI, SC,
4210 Converted, TemplateArgs);
4213 VarTemplate->AddPartialSpecialization(Partial, InsertPos);
4214 Specialization = Partial;
4216 // If we are providing an explicit specialization of a member variable
4217 // template specialization, make a note of that.
4218 if (PrevPartial && PrevPartial->getInstantiatedFromMember())
4219 PrevPartial->setMemberSpecialization();
4221 CheckTemplatePartialSpecialization(Partial);
4223 // Create a new class template specialization declaration node for
4224 // this explicit specialization or friend declaration.
4225 Specialization = VarTemplateSpecializationDecl::Create(
4226 Context, VarTemplate->getDeclContext(), TemplateKWLoc, TemplateNameLoc,
4227 VarTemplate, DI->getType(), DI, SC, Converted);
4228 Specialization->setTemplateArgsInfo(TemplateArgs);
4231 VarTemplate->AddSpecialization(Specialization, InsertPos);
4234 // C++ [temp.expl.spec]p6:
4235 // If a template, a member template or the member of a class template is
4236 // explicitly specialized then that specialization shall be declared
4237 // before the first use of that specialization that would cause an implicit
4238 // instantiation to take place, in every translation unit in which such a
4239 // use occurs; no diagnostic is required.
4240 if (PrevDecl && PrevDecl->getPointOfInstantiation().isValid()) {
4242 for (Decl *Prev = PrevDecl; Prev; Prev = Prev->getPreviousDecl()) {
4243 // Is there any previous explicit specialization declaration?
4244 if (getTemplateSpecializationKind(Prev) == TSK_ExplicitSpecialization) {
4251 SourceRange Range(TemplateNameLoc, RAngleLoc);
4252 Diag(TemplateNameLoc, diag::err_specialization_after_instantiation)
4255 Diag(PrevDecl->getPointOfInstantiation(),
4256 diag::note_instantiation_required_here)
4257 << (PrevDecl->getTemplateSpecializationKind() !=
4258 TSK_ImplicitInstantiation);
4263 Specialization->setTemplateKeywordLoc(TemplateKWLoc);
4264 Specialization->setLexicalDeclContext(CurContext);
4266 // Add the specialization into its lexical context, so that it can
4267 // be seen when iterating through the list of declarations in that
4268 // context. However, specializations are not found by name lookup.
4269 CurContext->addDecl(Specialization);
4271 // Note that this is an explicit specialization.
4272 Specialization->setSpecializationKind(TSK_ExplicitSpecialization);
4275 // Check that this isn't a redefinition of this specialization,
4276 // merging with previous declarations.
4277 LookupResult PrevSpec(*this, GetNameForDeclarator(D), LookupOrdinaryName,
4278 forRedeclarationInCurContext());
4279 PrevSpec.addDecl(PrevDecl);
4280 D.setRedeclaration(CheckVariableDeclaration(Specialization, PrevSpec));
4281 } else if (Specialization->isStaticDataMember() &&
4282 Specialization->isOutOfLine()) {
4283 Specialization->setAccess(VarTemplate->getAccess());
4286 return Specialization;
4290 /// A partial specialization whose template arguments have matched
4291 /// a given template-id.
4292 struct PartialSpecMatchResult {
4293 VarTemplatePartialSpecializationDecl *Partial;
4294 TemplateArgumentList *Args;
4296 } // end anonymous namespace
4299 Sema::CheckVarTemplateId(VarTemplateDecl *Template, SourceLocation TemplateLoc,
4300 SourceLocation TemplateNameLoc,
4301 const TemplateArgumentListInfo &TemplateArgs) {
4302 assert(Template && "A variable template id without template?");
4304 // Check that the template argument list is well-formed for this template.
4305 SmallVector<TemplateArgument, 4> Converted;
4306 if (CheckTemplateArgumentList(
4307 Template, TemplateNameLoc,
4308 const_cast<TemplateArgumentListInfo &>(TemplateArgs), false,
4309 Converted, /*UpdateArgsWithConversion=*/true))
4312 // Find the variable template specialization declaration that
4313 // corresponds to these arguments.
4314 void *InsertPos = nullptr;
4315 if (VarTemplateSpecializationDecl *Spec = Template->findSpecialization(
4316 Converted, InsertPos)) {
4317 checkSpecializationVisibility(TemplateNameLoc, Spec);
4318 // If we already have a variable template specialization, return it.
4322 // This is the first time we have referenced this variable template
4323 // specialization. Create the canonical declaration and add it to
4324 // the set of specializations, based on the closest partial specialization
4325 // that it represents. That is,
4326 VarDecl *InstantiationPattern = Template->getTemplatedDecl();
4327 TemplateArgumentList TemplateArgList(TemplateArgumentList::OnStack,
4329 TemplateArgumentList *InstantiationArgs = &TemplateArgList;
4330 bool AmbiguousPartialSpec = false;
4331 typedef PartialSpecMatchResult MatchResult;
4332 SmallVector<MatchResult, 4> Matched;
4333 SourceLocation PointOfInstantiation = TemplateNameLoc;
4334 TemplateSpecCandidateSet FailedCandidates(PointOfInstantiation,
4335 /*ForTakingAddress=*/false);
4337 // 1. Attempt to find the closest partial specialization that this
4338 // specializes, if any.
4339 // If any of the template arguments is dependent, then this is probably
4340 // a placeholder for an incomplete declarative context; which must be
4341 // complete by instantiation time. Thus, do not search through the partial
4342 // specializations yet.
4343 // TODO: Unify with InstantiateClassTemplateSpecialization()?
4344 // Perhaps better after unification of DeduceTemplateArguments() and
4345 // getMoreSpecializedPartialSpecialization().
4346 bool InstantiationDependent = false;
4347 if (!TemplateSpecializationType::anyDependentTemplateArguments(
4348 TemplateArgs, InstantiationDependent)) {
4350 SmallVector<VarTemplatePartialSpecializationDecl *, 4> PartialSpecs;
4351 Template->getPartialSpecializations(PartialSpecs);
4353 for (unsigned I = 0, N = PartialSpecs.size(); I != N; ++I) {
4354 VarTemplatePartialSpecializationDecl *Partial = PartialSpecs[I];
4355 TemplateDeductionInfo Info(FailedCandidates.getLocation());
4357 if (TemplateDeductionResult Result =
4358 DeduceTemplateArguments(Partial, TemplateArgList, Info)) {
4359 // Store the failed-deduction information for use in diagnostics, later.
4360 // TODO: Actually use the failed-deduction info?
4361 FailedCandidates.addCandidate().set(
4362 DeclAccessPair::make(Template, AS_public), Partial,
4363 MakeDeductionFailureInfo(Context, Result, Info));
4366 Matched.push_back(PartialSpecMatchResult());
4367 Matched.back().Partial = Partial;
4368 Matched.back().Args = Info.take();
4372 if (Matched.size() >= 1) {
4373 SmallVector<MatchResult, 4>::iterator Best = Matched.begin();
4374 if (Matched.size() == 1) {
4375 // -- If exactly one matching specialization is found, the
4376 // instantiation is generated from that specialization.
4377 // We don't need to do anything for this.
4379 // -- If more than one matching specialization is found, the
4380 // partial order rules (14.5.4.2) are used to determine
4381 // whether one of the specializations is more specialized
4382 // than the others. If none of the specializations is more
4383 // specialized than all of the other matching
4384 // specializations, then the use of the variable template is
4385 // ambiguous and the program is ill-formed.
4386 for (SmallVector<MatchResult, 4>::iterator P = Best + 1,
4387 PEnd = Matched.end();
4389 if (getMoreSpecializedPartialSpecialization(P->Partial, Best->Partial,
4390 PointOfInstantiation) ==
4395 // Determine if the best partial specialization is more specialized than
4397 for (SmallVector<MatchResult, 4>::iterator P = Matched.begin(),
4398 PEnd = Matched.end();
4400 if (P != Best && getMoreSpecializedPartialSpecialization(
4401 P->Partial, Best->Partial,
4402 PointOfInstantiation) != Best->Partial) {
4403 AmbiguousPartialSpec = true;
4409 // Instantiate using the best variable template partial specialization.
4410 InstantiationPattern = Best->Partial;
4411 InstantiationArgs = Best->Args;
4413 // -- If no match is found, the instantiation is generated
4414 // from the primary template.
4415 // InstantiationPattern = Template->getTemplatedDecl();
4419 // 2. Create the canonical declaration.
4420 // Note that we do not instantiate a definition until we see an odr-use
4421 // in DoMarkVarDeclReferenced().
4422 // FIXME: LateAttrs et al.?
4423 VarTemplateSpecializationDecl *Decl = BuildVarTemplateInstantiation(
4424 Template, InstantiationPattern, *InstantiationArgs, TemplateArgs,
4425 Converted, TemplateNameLoc, InsertPos /*, LateAttrs, StartingScope*/);
4429 if (AmbiguousPartialSpec) {
4430 // Partial ordering did not produce a clear winner. Complain.
4431 Decl->setInvalidDecl();
4432 Diag(PointOfInstantiation, diag::err_partial_spec_ordering_ambiguous)
4435 // Print the matching partial specializations.
4436 for (MatchResult P : Matched)
4437 Diag(P.Partial->getLocation(), diag::note_partial_spec_match)
4438 << getTemplateArgumentBindingsText(P.Partial->getTemplateParameters(),
4443 if (VarTemplatePartialSpecializationDecl *D =
4444 dyn_cast<VarTemplatePartialSpecializationDecl>(InstantiationPattern))
4445 Decl->setInstantiationOf(D, InstantiationArgs);
4447 checkSpecializationVisibility(TemplateNameLoc, Decl);
4449 assert(Decl && "No variable template specialization?");
4454 Sema::CheckVarTemplateId(const CXXScopeSpec &SS,
4455 const DeclarationNameInfo &NameInfo,
4456 VarTemplateDecl *Template, SourceLocation TemplateLoc,
4457 const TemplateArgumentListInfo *TemplateArgs) {
4459 DeclResult Decl = CheckVarTemplateId(Template, TemplateLoc, NameInfo.getLoc(),
4461 if (Decl.isInvalid())
4464 VarDecl *Var = cast<VarDecl>(Decl.get());
4465 if (!Var->getTemplateSpecializationKind())
4466 Var->setTemplateSpecializationKind(TSK_ImplicitInstantiation,
4469 // Build an ordinary singleton decl ref.
4470 return BuildDeclarationNameExpr(SS, NameInfo, Var,
4471 /*FoundD=*/nullptr, TemplateArgs);
4474 void Sema::diagnoseMissingTemplateArguments(TemplateName Name,
4475 SourceLocation Loc) {
4476 Diag(Loc, diag::err_template_missing_args)
4477 << (int)getTemplateNameKindForDiagnostics(Name) << Name;
4478 if (TemplateDecl *TD = Name.getAsTemplateDecl()) {
4479 Diag(TD->getLocation(), diag::note_template_decl_here)
4480 << TD->getTemplateParameters()->getSourceRange();
4485 Sema::CheckConceptTemplateId(const CXXScopeSpec &SS,
4486 SourceLocation TemplateKWLoc,
4487 const DeclarationNameInfo &ConceptNameInfo,
4488 NamedDecl *FoundDecl,
4489 ConceptDecl *NamedConcept,
4490 const TemplateArgumentListInfo *TemplateArgs) {
4491 assert(NamedConcept && "A concept template id without a template?");
4493 llvm::SmallVector<TemplateArgument, 4> Converted;
4494 if (CheckTemplateArgumentList(NamedConcept, ConceptNameInfo.getLoc(),
4495 const_cast<TemplateArgumentListInfo&>(*TemplateArgs),
4496 /*PartialTemplateArgs=*/false, Converted,
4497 /*UpdateArgsWithConversion=*/false))
4500 ConstraintSatisfaction Satisfaction;
4501 bool AreArgsDependent = false;
4502 for (TemplateArgument &Arg : Converted) {
4503 if (Arg.isDependent()) {
4504 AreArgsDependent = true;
4508 if (!AreArgsDependent &&
4509 CheckConstraintSatisfaction(NamedConcept,
4510 {NamedConcept->getConstraintExpr()},
4512 SourceRange(SS.isSet() ? SS.getBeginLoc() :
4513 ConceptNameInfo.getLoc(),
4514 TemplateArgs->getRAngleLoc()),
4518 return ConceptSpecializationExpr::Create(Context,
4519 SS.isSet() ? SS.getWithLocInContext(Context) : NestedNameSpecifierLoc{},
4520 TemplateKWLoc, ConceptNameInfo, FoundDecl, NamedConcept,
4521 ASTTemplateArgumentListInfo::Create(Context, *TemplateArgs), Converted,
4522 AreArgsDependent ? nullptr : &Satisfaction);
4525 ExprResult Sema::BuildTemplateIdExpr(const CXXScopeSpec &SS,
4526 SourceLocation TemplateKWLoc,
4529 const TemplateArgumentListInfo *TemplateArgs) {
4530 // FIXME: Can we do any checking at this point? I guess we could check the
4531 // template arguments that we have against the template name, if the template
4532 // name refers to a single template. That's not a terribly common case,
4534 // foo<int> could identify a single function unambiguously
4535 // This approach does NOT work, since f<int>(1);
4536 // gets resolved prior to resorting to overload resolution
4537 // i.e., template<class T> void f(double);
4538 // vs template<class T, class U> void f(U);
4540 // These should be filtered out by our callers.
4541 assert(!R.isAmbiguous() && "ambiguous lookup when building templateid");
4543 // Non-function templates require a template argument list.
4544 if (auto *TD = R.getAsSingle<TemplateDecl>()) {
4545 if (!TemplateArgs && !isa<FunctionTemplateDecl>(TD)) {
4546 diagnoseMissingTemplateArguments(TemplateName(TD), R.getNameLoc());
4551 auto AnyDependentArguments = [&]() -> bool {
4552 bool InstantiationDependent;
4553 return TemplateArgs &&
4554 TemplateSpecializationType::anyDependentTemplateArguments(
4555 *TemplateArgs, InstantiationDependent);
4558 // In C++1y, check variable template ids.
4559 if (R.getAsSingle<VarTemplateDecl>() && !AnyDependentArguments()) {
4560 return CheckVarTemplateId(SS, R.getLookupNameInfo(),
4561 R.getAsSingle<VarTemplateDecl>(),
4562 TemplateKWLoc, TemplateArgs);
4565 if (R.getAsSingle<ConceptDecl>()) {
4566 return CheckConceptTemplateId(SS, TemplateKWLoc, R.getLookupNameInfo(),
4568 R.getAsSingle<ConceptDecl>(), TemplateArgs);
4571 // We don't want lookup warnings at this point.
4572 R.suppressDiagnostics();
4574 UnresolvedLookupExpr *ULE
4575 = UnresolvedLookupExpr::Create(Context, R.getNamingClass(),
4576 SS.getWithLocInContext(Context),
4578 R.getLookupNameInfo(),
4579 RequiresADL, TemplateArgs,
4580 R.begin(), R.end());
4585 // We actually only call this from template instantiation.
4587 Sema::BuildQualifiedTemplateIdExpr(CXXScopeSpec &SS,
4588 SourceLocation TemplateKWLoc,
4589 const DeclarationNameInfo &NameInfo,
4590 const TemplateArgumentListInfo *TemplateArgs) {
4592 assert(TemplateArgs || TemplateKWLoc.isValid());
4594 if (!(DC = computeDeclContext(SS, false)) ||
4595 DC->isDependentContext() ||
4596 RequireCompleteDeclContext(SS, DC))
4597 return BuildDependentDeclRefExpr(SS, TemplateKWLoc, NameInfo, TemplateArgs);
4599 bool MemberOfUnknownSpecialization;
4600 LookupResult R(*this, NameInfo, LookupOrdinaryName);
4601 if (LookupTemplateName(R, (Scope *)nullptr, SS, QualType(),
4602 /*Entering*/false, MemberOfUnknownSpecialization,
4606 if (R.isAmbiguous())
4610 Diag(NameInfo.getLoc(), diag::err_no_member)
4611 << NameInfo.getName() << DC << SS.getRange();
4615 if (ClassTemplateDecl *Temp = R.getAsSingle<ClassTemplateDecl>()) {
4616 Diag(NameInfo.getLoc(), diag::err_template_kw_refers_to_class_template)
4618 << NameInfo.getName().getAsString() << SS.getRange();
4619 Diag(Temp->getLocation(), diag::note_referenced_class_template);
4623 return BuildTemplateIdExpr(SS, TemplateKWLoc, R, /*ADL*/ false, TemplateArgs);
4626 /// Form a dependent template name.
4628 /// This action forms a dependent template name given the template
4629 /// name and its (presumably dependent) scope specifier. For
4630 /// example, given "MetaFun::template apply", the scope specifier \p
4631 /// SS will be "MetaFun::", \p TemplateKWLoc contains the location
4632 /// of the "template" keyword, and "apply" is the \p Name.
4633 TemplateNameKind Sema::ActOnDependentTemplateName(Scope *S,
4635 SourceLocation TemplateKWLoc,
4636 const UnqualifiedId &Name,
4637 ParsedType ObjectType,
4638 bool EnteringContext,
4640 bool AllowInjectedClassName) {
4641 if (TemplateKWLoc.isValid() && S && !S->getTemplateParamParent())
4643 getLangOpts().CPlusPlus11 ?
4644 diag::warn_cxx98_compat_template_outside_of_template :
4645 diag::ext_template_outside_of_template)
4646 << FixItHint::CreateRemoval(TemplateKWLoc);
4648 DeclContext *LookupCtx = nullptr;
4650 LookupCtx = computeDeclContext(SS, EnteringContext);
4651 if (!LookupCtx && ObjectType)
4652 LookupCtx = computeDeclContext(ObjectType.get());
4654 // C++0x [temp.names]p5:
4655 // If a name prefixed by the keyword template is not the name of
4656 // a template, the program is ill-formed. [Note: the keyword
4657 // template may not be applied to non-template members of class
4658 // templates. -end note ] [ Note: as is the case with the
4659 // typename prefix, the template prefix is allowed in cases
4660 // where it is not strictly necessary; i.e., when the
4661 // nested-name-specifier or the expression on the left of the ->
4662 // or . is not dependent on a template-parameter, or the use
4663 // does not appear in the scope of a template. -end note]
4665 // Note: C++03 was more strict here, because it banned the use of
4666 // the "template" keyword prior to a template-name that was not a
4667 // dependent name. C++ DR468 relaxed this requirement (the
4668 // "template" keyword is now permitted). We follow the C++0x
4669 // rules, even in C++03 mode with a warning, retroactively applying the DR.
4670 bool MemberOfUnknownSpecialization;
4671 TemplateNameKind TNK = isTemplateName(S, SS, TemplateKWLoc.isValid(), Name,
4672 ObjectType, EnteringContext, Result,
4673 MemberOfUnknownSpecialization);
4674 if (TNK == TNK_Non_template && MemberOfUnknownSpecialization) {
4675 // This is a dependent template. Handle it below.
4676 } else if (TNK == TNK_Non_template) {
4677 // Do the lookup again to determine if this is a "nothing found" case or
4678 // a "not a template" case. FIXME: Refactor isTemplateName so we don't
4680 DeclarationNameInfo DNI = GetNameFromUnqualifiedId(Name);
4681 LookupResult R(*this, DNI.getName(), Name.getBeginLoc(),
4682 LookupOrdinaryName);
4684 if (!LookupTemplateName(R, S, SS, ObjectType.get(), EnteringContext,
4685 MOUS, TemplateKWLoc) && !R.isAmbiguous())
4686 Diag(Name.getBeginLoc(), diag::err_no_member)
4687 << DNI.getName() << LookupCtx << SS.getRange();
4688 return TNK_Non_template;
4690 // We found something; return it.
4691 auto *LookupRD = dyn_cast<CXXRecordDecl>(LookupCtx);
4692 if (!AllowInjectedClassName && SS.isSet() && LookupRD &&
4693 Name.getKind() == UnqualifiedIdKind::IK_Identifier &&
4694 Name.Identifier && LookupRD->getIdentifier() == Name.Identifier) {
4695 // C++14 [class.qual]p2:
4696 // In a lookup in which function names are not ignored and the
4697 // nested-name-specifier nominates a class C, if the name specified
4698 // [...] is the injected-class-name of C, [...] the name is instead
4699 // considered to name the constructor
4701 // We don't get here if naming the constructor would be valid, so we
4702 // just reject immediately and recover by treating the
4703 // injected-class-name as naming the template.
4704 Diag(Name.getBeginLoc(),
4705 diag::ext_out_of_line_qualified_id_type_names_constructor)
4707 << 0 /*injected-class-name used as template name*/
4708 << 1 /*'template' keyword was used*/;
4714 NestedNameSpecifier *Qualifier = SS.getScopeRep();
4716 switch (Name.getKind()) {
4717 case UnqualifiedIdKind::IK_Identifier:
4718 Result = TemplateTy::make(Context.getDependentTemplateName(Qualifier,
4720 return TNK_Dependent_template_name;
4722 case UnqualifiedIdKind::IK_OperatorFunctionId:
4723 Result = TemplateTy::make(Context.getDependentTemplateName(Qualifier,
4724 Name.OperatorFunctionId.Operator));
4725 return TNK_Function_template;
4727 case UnqualifiedIdKind::IK_LiteralOperatorId:
4728 llvm_unreachable("literal operator id cannot have a dependent scope");
4734 Diag(Name.getBeginLoc(), diag::err_template_kw_refers_to_non_template)
4735 << GetNameFromUnqualifiedId(Name).getName() << Name.getSourceRange()
4737 return TNK_Non_template;
4740 bool Sema::CheckTemplateTypeArgument(TemplateTypeParmDecl *Param,
4741 TemplateArgumentLoc &AL,
4742 SmallVectorImpl<TemplateArgument> &Converted) {
4743 const TemplateArgument &Arg = AL.getArgument();
4745 TypeSourceInfo *TSI = nullptr;
4747 // Check template type parameter.
4748 switch(Arg.getKind()) {
4749 case TemplateArgument::Type:
4750 // C++ [temp.arg.type]p1:
4751 // A template-argument for a template-parameter which is a
4752 // type shall be a type-id.
4753 ArgType = Arg.getAsType();
4754 TSI = AL.getTypeSourceInfo();
4756 case TemplateArgument::Template:
4757 case TemplateArgument::TemplateExpansion: {
4758 // We have a template type parameter but the template argument
4759 // is a template without any arguments.
4760 SourceRange SR = AL.getSourceRange();
4761 TemplateName Name = Arg.getAsTemplateOrTemplatePattern();
4762 diagnoseMissingTemplateArguments(Name, SR.getEnd());
4765 case TemplateArgument::Expression: {
4766 // We have a template type parameter but the template argument is an
4767 // expression; see if maybe it is missing the "typename" keyword.
4769 DeclarationNameInfo NameInfo;
4771 if (DeclRefExpr *ArgExpr = dyn_cast<DeclRefExpr>(Arg.getAsExpr())) {
4772 SS.Adopt(ArgExpr->getQualifierLoc());
4773 NameInfo = ArgExpr->getNameInfo();
4774 } else if (DependentScopeDeclRefExpr *ArgExpr =
4775 dyn_cast<DependentScopeDeclRefExpr>(Arg.getAsExpr())) {
4776 SS.Adopt(ArgExpr->getQualifierLoc());
4777 NameInfo = ArgExpr->getNameInfo();
4778 } else if (CXXDependentScopeMemberExpr *ArgExpr =
4779 dyn_cast<CXXDependentScopeMemberExpr>(Arg.getAsExpr())) {
4780 if (ArgExpr->isImplicitAccess()) {
4781 SS.Adopt(ArgExpr->getQualifierLoc());
4782 NameInfo = ArgExpr->getMemberNameInfo();
4786 if (auto *II = NameInfo.getName().getAsIdentifierInfo()) {
4787 LookupResult Result(*this, NameInfo, LookupOrdinaryName);
4788 LookupParsedName(Result, CurScope, &SS);
4790 if (Result.getAsSingle<TypeDecl>() ||
4791 Result.getResultKind() ==
4792 LookupResult::NotFoundInCurrentInstantiation) {
4793 // Suggest that the user add 'typename' before the NNS.
4794 SourceLocation Loc = AL.getSourceRange().getBegin();
4795 Diag(Loc, getLangOpts().MSVCCompat
4796 ? diag::ext_ms_template_type_arg_missing_typename
4797 : diag::err_template_arg_must_be_type_suggest)
4798 << FixItHint::CreateInsertion(Loc, "typename ");
4799 Diag(Param->getLocation(), diag::note_template_param_here);
4801 // Recover by synthesizing a type using the location information that we
4804 Context.getDependentNameType(ETK_Typename, SS.getScopeRep(), II);
4806 DependentNameTypeLoc TL = TLB.push<DependentNameTypeLoc>(ArgType);
4807 TL.setElaboratedKeywordLoc(SourceLocation(/*synthesized*/));
4808 TL.setQualifierLoc(SS.getWithLocInContext(Context));
4809 TL.setNameLoc(NameInfo.getLoc());
4810 TSI = TLB.getTypeSourceInfo(Context, ArgType);
4812 // Overwrite our input TemplateArgumentLoc so that we can recover
4814 AL = TemplateArgumentLoc(TemplateArgument(ArgType),
4815 TemplateArgumentLocInfo(TSI));
4824 // We have a template type parameter but the template argument
4826 SourceRange SR = AL.getSourceRange();
4827 Diag(SR.getBegin(), diag::err_template_arg_must_be_type) << SR;
4828 Diag(Param->getLocation(), diag::note_template_param_here);
4834 if (CheckTemplateArgument(Param, TSI))
4837 // Add the converted template type argument.
4838 ArgType = Context.getCanonicalType(ArgType);
4841 // If an explicitly-specified template argument type is a lifetime type
4842 // with no lifetime qualifier, the __strong lifetime qualifier is inferred.
4843 if (getLangOpts().ObjCAutoRefCount &&
4844 ArgType->isObjCLifetimeType() &&
4845 !ArgType.getObjCLifetime()) {
4847 Qs.setObjCLifetime(Qualifiers::OCL_Strong);
4848 ArgType = Context.getQualifiedType(ArgType, Qs);
4851 Converted.push_back(TemplateArgument(ArgType));
4855 /// Substitute template arguments into the default template argument for
4856 /// the given template type parameter.
4858 /// \param SemaRef the semantic analysis object for which we are performing
4859 /// the substitution.
4861 /// \param Template the template that we are synthesizing template arguments
4864 /// \param TemplateLoc the location of the template name that started the
4865 /// template-id we are checking.
4867 /// \param RAngleLoc the location of the right angle bracket ('>') that
4868 /// terminates the template-id.
4870 /// \param Param the template template parameter whose default we are
4871 /// substituting into.
4873 /// \param Converted the list of template arguments provided for template
4874 /// parameters that precede \p Param in the template parameter list.
4875 /// \returns the substituted template argument, or NULL if an error occurred.
4876 static TypeSourceInfo *
4877 SubstDefaultTemplateArgument(Sema &SemaRef,
4878 TemplateDecl *Template,
4879 SourceLocation TemplateLoc,
4880 SourceLocation RAngleLoc,
4881 TemplateTypeParmDecl *Param,
4882 SmallVectorImpl<TemplateArgument> &Converted) {
4883 TypeSourceInfo *ArgType = Param->getDefaultArgumentInfo();
4885 // If the argument type is dependent, instantiate it now based
4886 // on the previously-computed template arguments.
4887 if (ArgType->getType()->isInstantiationDependentType()) {
4888 Sema::InstantiatingTemplate Inst(SemaRef, TemplateLoc,
4889 Param, Template, Converted,
4890 SourceRange(TemplateLoc, RAngleLoc));
4891 if (Inst.isInvalid())
4894 TemplateArgumentList TemplateArgs(TemplateArgumentList::OnStack, Converted);
4896 // Only substitute for the innermost template argument list.
4897 MultiLevelTemplateArgumentList TemplateArgLists;
4898 TemplateArgLists.addOuterTemplateArguments(&TemplateArgs);
4899 for (unsigned i = 0, e = Param->getDepth(); i != e; ++i)
4900 TemplateArgLists.addOuterTemplateArguments(None);
4902 Sema::ContextRAII SavedContext(SemaRef, Template->getDeclContext());
4904 SemaRef.SubstType(ArgType, TemplateArgLists,
4905 Param->getDefaultArgumentLoc(), Param->getDeclName());
4911 /// Substitute template arguments into the default template argument for
4912 /// the given non-type template parameter.
4914 /// \param SemaRef the semantic analysis object for which we are performing
4915 /// the substitution.
4917 /// \param Template the template that we are synthesizing template arguments
4920 /// \param TemplateLoc the location of the template name that started the
4921 /// template-id we are checking.
4923 /// \param RAngleLoc the location of the right angle bracket ('>') that
4924 /// terminates the template-id.
4926 /// \param Param the non-type template parameter whose default we are
4927 /// substituting into.
4929 /// \param Converted the list of template arguments provided for template
4930 /// parameters that precede \p Param in the template parameter list.
4932 /// \returns the substituted template argument, or NULL if an error occurred.
4934 SubstDefaultTemplateArgument(Sema &SemaRef,
4935 TemplateDecl *Template,
4936 SourceLocation TemplateLoc,
4937 SourceLocation RAngleLoc,
4938 NonTypeTemplateParmDecl *Param,
4939 SmallVectorImpl<TemplateArgument> &Converted) {
4940 Sema::InstantiatingTemplate Inst(SemaRef, TemplateLoc,
4941 Param, Template, Converted,
4942 SourceRange(TemplateLoc, RAngleLoc));
4943 if (Inst.isInvalid())
4946 TemplateArgumentList TemplateArgs(TemplateArgumentList::OnStack, Converted);
4948 // Only substitute for the innermost template argument list.
4949 MultiLevelTemplateArgumentList TemplateArgLists;
4950 TemplateArgLists.addOuterTemplateArguments(&TemplateArgs);
4951 for (unsigned i = 0, e = Param->getDepth(); i != e; ++i)
4952 TemplateArgLists.addOuterTemplateArguments(None);
4954 Sema::ContextRAII SavedContext(SemaRef, Template->getDeclContext());
4955 EnterExpressionEvaluationContext ConstantEvaluated(
4956 SemaRef, Sema::ExpressionEvaluationContext::ConstantEvaluated);
4957 return SemaRef.SubstExpr(Param->getDefaultArgument(), TemplateArgLists);
4960 /// Substitute template arguments into the default template argument for
4961 /// the given template template parameter.
4963 /// \param SemaRef the semantic analysis object for which we are performing
4964 /// the substitution.
4966 /// \param Template the template that we are synthesizing template arguments
4969 /// \param TemplateLoc the location of the template name that started the
4970 /// template-id we are checking.
4972 /// \param RAngleLoc the location of the right angle bracket ('>') that
4973 /// terminates the template-id.
4975 /// \param Param the template template parameter whose default we are
4976 /// substituting into.
4978 /// \param Converted the list of template arguments provided for template
4979 /// parameters that precede \p Param in the template parameter list.
4981 /// \param QualifierLoc Will be set to the nested-name-specifier (with
4982 /// source-location information) that precedes the template name.
4984 /// \returns the substituted template argument, or NULL if an error occurred.
4986 SubstDefaultTemplateArgument(Sema &SemaRef,
4987 TemplateDecl *Template,
4988 SourceLocation TemplateLoc,
4989 SourceLocation RAngleLoc,
4990 TemplateTemplateParmDecl *Param,
4991 SmallVectorImpl<TemplateArgument> &Converted,
4992 NestedNameSpecifierLoc &QualifierLoc) {
4993 Sema::InstantiatingTemplate Inst(
4994 SemaRef, TemplateLoc, TemplateParameter(Param), Template, Converted,
4995 SourceRange(TemplateLoc, RAngleLoc));
4996 if (Inst.isInvalid())
4997 return TemplateName();
4999 TemplateArgumentList TemplateArgs(TemplateArgumentList::OnStack, Converted);
5001 // Only substitute for the innermost template argument list.
5002 MultiLevelTemplateArgumentList TemplateArgLists;
5003 TemplateArgLists.addOuterTemplateArguments(&TemplateArgs);
5004 for (unsigned i = 0, e = Param->getDepth(); i != e; ++i)
5005 TemplateArgLists.addOuterTemplateArguments(None);
5007 Sema::ContextRAII SavedContext(SemaRef, Template->getDeclContext());
5008 // Substitute into the nested-name-specifier first,
5009 QualifierLoc = Param->getDefaultArgument().getTemplateQualifierLoc();
5012 SemaRef.SubstNestedNameSpecifierLoc(QualifierLoc, TemplateArgLists);
5014 return TemplateName();
5017 return SemaRef.SubstTemplateName(
5019 Param->getDefaultArgument().getArgument().getAsTemplate(),
5020 Param->getDefaultArgument().getTemplateNameLoc(),
5024 /// If the given template parameter has a default template
5025 /// argument, substitute into that default template argument and
5026 /// return the corresponding template argument.
5028 Sema::SubstDefaultTemplateArgumentIfAvailable(TemplateDecl *Template,
5029 SourceLocation TemplateLoc,
5030 SourceLocation RAngleLoc,
5032 SmallVectorImpl<TemplateArgument>
5034 bool &HasDefaultArg) {
5035 HasDefaultArg = false;
5037 if (TemplateTypeParmDecl *TypeParm = dyn_cast<TemplateTypeParmDecl>(Param)) {
5038 if (!hasVisibleDefaultArgument(TypeParm))
5039 return TemplateArgumentLoc();
5041 HasDefaultArg = true;
5042 TypeSourceInfo *DI = SubstDefaultTemplateArgument(*this, Template,
5048 return TemplateArgumentLoc(TemplateArgument(DI->getType()), DI);
5050 return TemplateArgumentLoc();
5053 if (NonTypeTemplateParmDecl *NonTypeParm
5054 = dyn_cast<NonTypeTemplateParmDecl>(Param)) {
5055 if (!hasVisibleDefaultArgument(NonTypeParm))
5056 return TemplateArgumentLoc();
5058 HasDefaultArg = true;
5059 ExprResult Arg = SubstDefaultTemplateArgument(*this, Template,
5064 if (Arg.isInvalid())
5065 return TemplateArgumentLoc();
5067 Expr *ArgE = Arg.getAs<Expr>();
5068 return TemplateArgumentLoc(TemplateArgument(ArgE), ArgE);
5071 TemplateTemplateParmDecl *TempTempParm
5072 = cast<TemplateTemplateParmDecl>(Param);
5073 if (!hasVisibleDefaultArgument(TempTempParm))
5074 return TemplateArgumentLoc();
5076 HasDefaultArg = true;
5077 NestedNameSpecifierLoc QualifierLoc;
5078 TemplateName TName = SubstDefaultTemplateArgument(*this, Template,
5085 return TemplateArgumentLoc();
5087 return TemplateArgumentLoc(TemplateArgument(TName),
5088 TempTempParm->getDefaultArgument().getTemplateQualifierLoc(),
5089 TempTempParm->getDefaultArgument().getTemplateNameLoc());
5092 /// Convert a template-argument that we parsed as a type into a template, if
5093 /// possible. C++ permits injected-class-names to perform dual service as
5094 /// template template arguments and as template type arguments.
5095 static TemplateArgumentLoc convertTypeTemplateArgumentToTemplate(TypeLoc TLoc) {
5096 // Extract and step over any surrounding nested-name-specifier.
5097 NestedNameSpecifierLoc QualLoc;
5098 if (auto ETLoc = TLoc.getAs<ElaboratedTypeLoc>()) {
5099 if (ETLoc.getTypePtr()->getKeyword() != ETK_None)
5100 return TemplateArgumentLoc();
5102 QualLoc = ETLoc.getQualifierLoc();
5103 TLoc = ETLoc.getNamedTypeLoc();
5106 // If this type was written as an injected-class-name, it can be used as a
5107 // template template argument.
5108 if (auto InjLoc = TLoc.getAs<InjectedClassNameTypeLoc>())
5109 return TemplateArgumentLoc(InjLoc.getTypePtr()->getTemplateName(),
5110 QualLoc, InjLoc.getNameLoc());
5112 // If this type was written as an injected-class-name, it may have been
5113 // converted to a RecordType during instantiation. If the RecordType is
5114 // *not* wrapped in a TemplateSpecializationType and denotes a class
5115 // template specialization, it must have come from an injected-class-name.
5116 if (auto RecLoc = TLoc.getAs<RecordTypeLoc>())
5118 dyn_cast<ClassTemplateSpecializationDecl>(RecLoc.getDecl()))
5119 return TemplateArgumentLoc(TemplateName(CTSD->getSpecializedTemplate()),
5120 QualLoc, RecLoc.getNameLoc());
5122 return TemplateArgumentLoc();
5125 /// Check that the given template argument corresponds to the given
5126 /// template parameter.
5128 /// \param Param The template parameter against which the argument will be
5131 /// \param Arg The template argument, which may be updated due to conversions.
5133 /// \param Template The template in which the template argument resides.
5135 /// \param TemplateLoc The location of the template name for the template
5136 /// whose argument list we're matching.
5138 /// \param RAngleLoc The location of the right angle bracket ('>') that closes
5139 /// the template argument list.
5141 /// \param ArgumentPackIndex The index into the argument pack where this
5142 /// argument will be placed. Only valid if the parameter is a parameter pack.
5144 /// \param Converted The checked, converted argument will be added to the
5145 /// end of this small vector.
5147 /// \param CTAK Describes how we arrived at this particular template argument:
5148 /// explicitly written, deduced, etc.
5150 /// \returns true on error, false otherwise.
5151 bool Sema::CheckTemplateArgument(NamedDecl *Param,
5152 TemplateArgumentLoc &Arg,
5153 NamedDecl *Template,
5154 SourceLocation TemplateLoc,
5155 SourceLocation RAngleLoc,
5156 unsigned ArgumentPackIndex,
5157 SmallVectorImpl<TemplateArgument> &Converted,
5158 CheckTemplateArgumentKind CTAK) {
5159 // Check template type parameters.
5160 if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(Param))
5161 return CheckTemplateTypeArgument(TTP, Arg, Converted);
5163 // Check non-type template parameters.
5164 if (NonTypeTemplateParmDecl *NTTP =dyn_cast<NonTypeTemplateParmDecl>(Param)) {
5165 // Do substitution on the type of the non-type template parameter
5166 // with the template arguments we've seen thus far. But if the
5167 // template has a dependent context then we cannot substitute yet.
5168 QualType NTTPType = NTTP->getType();
5169 if (NTTP->isParameterPack() && NTTP->isExpandedParameterPack())
5170 NTTPType = NTTP->getExpansionType(ArgumentPackIndex);
5172 if (NTTPType->isInstantiationDependentType() &&
5173 !isa<TemplateTemplateParmDecl>(Template) &&
5174 !Template->getDeclContext()->isDependentContext()) {
5175 // Do substitution on the type of the non-type template parameter.
5176 InstantiatingTemplate Inst(*this, TemplateLoc, Template,
5178 SourceRange(TemplateLoc, RAngleLoc));
5179 if (Inst.isInvalid())
5182 TemplateArgumentList TemplateArgs(TemplateArgumentList::OnStack,
5185 // If the parameter is a pack expansion, expand this slice of the pack.
5186 if (auto *PET = NTTPType->getAs<PackExpansionType>()) {
5187 Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(*this,
5189 NTTPType = SubstType(PET->getPattern(),
5190 MultiLevelTemplateArgumentList(TemplateArgs),
5191 NTTP->getLocation(),
5192 NTTP->getDeclName());
5194 NTTPType = SubstType(NTTPType,
5195 MultiLevelTemplateArgumentList(TemplateArgs),
5196 NTTP->getLocation(),
5197 NTTP->getDeclName());
5200 // If that worked, check the non-type template parameter type
5202 if (!NTTPType.isNull())
5203 NTTPType = CheckNonTypeTemplateParameterType(NTTPType,
5204 NTTP->getLocation());
5205 if (NTTPType.isNull())
5209 switch (Arg.getArgument().getKind()) {
5210 case TemplateArgument::Null:
5211 llvm_unreachable("Should never see a NULL template argument here");
5213 case TemplateArgument::Expression: {
5214 TemplateArgument Result;
5215 unsigned CurSFINAEErrors = NumSFINAEErrors;
5217 CheckTemplateArgument(NTTP, NTTPType, Arg.getArgument().getAsExpr(),
5219 if (Res.isInvalid())
5221 // If the current template argument causes an error, give up now.
5222 if (CurSFINAEErrors < NumSFINAEErrors)
5225 // If the resulting expression is new, then use it in place of the
5226 // old expression in the template argument.
5227 if (Res.get() != Arg.getArgument().getAsExpr()) {
5228 TemplateArgument TA(Res.get());
5229 Arg = TemplateArgumentLoc(TA, Res.get());
5232 Converted.push_back(Result);
5236 case TemplateArgument::Declaration:
5237 case TemplateArgument::Integral:
5238 case TemplateArgument::NullPtr:
5239 // We've already checked this template argument, so just copy
5240 // it to the list of converted arguments.
5241 Converted.push_back(Arg.getArgument());
5244 case TemplateArgument::Template:
5245 case TemplateArgument::TemplateExpansion:
5246 // We were given a template template argument. It may not be ill-formed;
5248 if (DependentTemplateName *DTN
5249 = Arg.getArgument().getAsTemplateOrTemplatePattern()
5250 .getAsDependentTemplateName()) {
5251 // We have a template argument such as \c T::template X, which we
5252 // parsed as a template template argument. However, since we now
5253 // know that we need a non-type template argument, convert this
5254 // template name into an expression.
5256 DeclarationNameInfo NameInfo(DTN->getIdentifier(),
5257 Arg.getTemplateNameLoc());
5260 SS.Adopt(Arg.getTemplateQualifierLoc());
5261 // FIXME: the template-template arg was a DependentTemplateName,
5262 // so it was provided with a template keyword. However, its source
5263 // location is not stored in the template argument structure.
5264 SourceLocation TemplateKWLoc;
5265 ExprResult E = DependentScopeDeclRefExpr::Create(
5266 Context, SS.getWithLocInContext(Context), TemplateKWLoc, NameInfo,
5269 // If we parsed the template argument as a pack expansion, create a
5270 // pack expansion expression.
5271 if (Arg.getArgument().getKind() == TemplateArgument::TemplateExpansion){
5272 E = ActOnPackExpansion(E.get(), Arg.getTemplateEllipsisLoc());
5277 TemplateArgument Result;
5278 E = CheckTemplateArgument(NTTP, NTTPType, E.get(), Result);
5282 Converted.push_back(Result);
5286 // We have a template argument that actually does refer to a class
5287 // template, alias template, or template template parameter, and
5288 // therefore cannot be a non-type template argument.
5289 Diag(Arg.getLocation(), diag::err_template_arg_must_be_expr)
5290 << Arg.getSourceRange();
5292 Diag(Param->getLocation(), diag::note_template_param_here);
5295 case TemplateArgument::Type: {
5296 // We have a non-type template parameter but the template
5297 // argument is a type.
5299 // C++ [temp.arg]p2:
5300 // In a template-argument, an ambiguity between a type-id and
5301 // an expression is resolved to a type-id, regardless of the
5302 // form of the corresponding template-parameter.
5304 // We warn specifically about this case, since it can be rather
5305 // confusing for users.
5306 QualType T = Arg.getArgument().getAsType();
5307 SourceRange SR = Arg.getSourceRange();
5308 if (T->isFunctionType())
5309 Diag(SR.getBegin(), diag::err_template_arg_nontype_ambig) << SR << T;
5311 Diag(SR.getBegin(), diag::err_template_arg_must_be_expr) << SR;
5312 Diag(Param->getLocation(), diag::note_template_param_here);
5316 case TemplateArgument::Pack:
5317 llvm_unreachable("Caller must expand template argument packs");
5324 // Check template template parameters.
5325 TemplateTemplateParmDecl *TempParm = cast<TemplateTemplateParmDecl>(Param);
5327 TemplateParameterList *Params = TempParm->getTemplateParameters();
5328 if (TempParm->isExpandedParameterPack())
5329 Params = TempParm->getExpansionTemplateParameters(ArgumentPackIndex);
5331 // Substitute into the template parameter list of the template
5332 // template parameter, since previously-supplied template arguments
5333 // may appear within the template template parameter.
5335 // FIXME: Skip this if the parameters aren't instantiation-dependent.
5337 // Set up a template instantiation context.
5338 LocalInstantiationScope Scope(*this);
5339 InstantiatingTemplate Inst(*this, TemplateLoc, Template,
5340 TempParm, Converted,
5341 SourceRange(TemplateLoc, RAngleLoc));
5342 if (Inst.isInvalid())
5345 TemplateArgumentList TemplateArgs(TemplateArgumentList::OnStack, Converted);
5346 Params = SubstTemplateParams(Params, CurContext,
5347 MultiLevelTemplateArgumentList(TemplateArgs));
5352 // C++1z [temp.local]p1: (DR1004)
5353 // When [the injected-class-name] is used [...] as a template-argument for
5354 // a template template-parameter [...] it refers to the class template
5356 if (Arg.getArgument().getKind() == TemplateArgument::Type) {
5357 TemplateArgumentLoc ConvertedArg = convertTypeTemplateArgumentToTemplate(
5358 Arg.getTypeSourceInfo()->getTypeLoc());
5359 if (!ConvertedArg.getArgument().isNull())
5363 switch (Arg.getArgument().getKind()) {
5364 case TemplateArgument::Null:
5365 llvm_unreachable("Should never see a NULL template argument here");
5367 case TemplateArgument::Template:
5368 case TemplateArgument::TemplateExpansion:
5369 if (CheckTemplateTemplateArgument(TempParm, Params, Arg))
5372 Converted.push_back(Arg.getArgument());
5375 case TemplateArgument::Expression:
5376 case TemplateArgument::Type:
5377 // We have a template template parameter but the template
5378 // argument does not refer to a template.
5379 Diag(Arg.getLocation(), diag::err_template_arg_must_be_template)
5380 << getLangOpts().CPlusPlus11;
5383 case TemplateArgument::Declaration:
5384 llvm_unreachable("Declaration argument with template template parameter");
5385 case TemplateArgument::Integral:
5386 llvm_unreachable("Integral argument with template template parameter");
5387 case TemplateArgument::NullPtr:
5388 llvm_unreachable("Null pointer argument with template template parameter");
5390 case TemplateArgument::Pack:
5391 llvm_unreachable("Caller must expand template argument packs");
5397 /// Check whether the template parameter is a pack expansion, and if so,
5398 /// determine the number of parameters produced by that expansion. For instance:
5401 /// template<typename ...Ts> struct A {
5402 /// template<Ts ...NTs, template<Ts> class ...TTs, typename ...Us> struct B;
5406 /// In \c A<int,int>::B, \c NTs and \c TTs have expanded pack size 2, and \c Us
5407 /// is not a pack expansion, so returns an empty Optional.
5408 static Optional<unsigned> getExpandedPackSize(NamedDecl *Param) {
5409 if (TemplateTypeParmDecl *TTP
5410 = dyn_cast<TemplateTypeParmDecl>(Param)) {
5411 if (TTP->isExpandedParameterPack())
5412 return TTP->getNumExpansionParameters();
5415 if (NonTypeTemplateParmDecl *NTTP
5416 = dyn_cast<NonTypeTemplateParmDecl>(Param)) {
5417 if (NTTP->isExpandedParameterPack())
5418 return NTTP->getNumExpansionTypes();
5421 if (TemplateTemplateParmDecl *TTP
5422 = dyn_cast<TemplateTemplateParmDecl>(Param)) {
5423 if (TTP->isExpandedParameterPack())
5424 return TTP->getNumExpansionTemplateParameters();
5430 /// Diagnose a missing template argument.
5431 template<typename TemplateParmDecl>
5432 static bool diagnoseMissingArgument(Sema &S, SourceLocation Loc,
5434 const TemplateParmDecl *D,
5435 TemplateArgumentListInfo &Args) {
5436 // Dig out the most recent declaration of the template parameter; there may be
5437 // declarations of the template that are more recent than TD.
5438 D = cast<TemplateParmDecl>(cast<TemplateDecl>(TD->getMostRecentDecl())
5439 ->getTemplateParameters()
5440 ->getParam(D->getIndex()));
5442 // If there's a default argument that's not visible, diagnose that we're
5443 // missing a module import.
5444 llvm::SmallVector<Module*, 8> Modules;
5445 if (D->hasDefaultArgument() && !S.hasVisibleDefaultArgument(D, &Modules)) {
5446 S.diagnoseMissingImport(Loc, cast<NamedDecl>(TD),
5447 D->getDefaultArgumentLoc(), Modules,
5448 Sema::MissingImportKind::DefaultArgument,
5453 // FIXME: If there's a more recent default argument that *is* visible,
5454 // diagnose that it was declared too late.
5456 TemplateParameterList *Params = TD->getTemplateParameters();
5458 S.Diag(Loc, diag::err_template_arg_list_different_arity)
5459 << /*not enough args*/0
5460 << (int)S.getTemplateNameKindForDiagnostics(TemplateName(TD))
5462 S.Diag(TD->getLocation(), diag::note_template_decl_here)
5463 << Params->getSourceRange();
5467 /// Check that the given template argument list is well-formed
5468 /// for specializing the given template.
5469 bool Sema::CheckTemplateArgumentList(
5470 TemplateDecl *Template, SourceLocation TemplateLoc,
5471 TemplateArgumentListInfo &TemplateArgs, bool PartialTemplateArgs,
5472 SmallVectorImpl<TemplateArgument> &Converted,
5473 bool UpdateArgsWithConversions, bool *ConstraintsNotSatisfied) {
5475 if (ConstraintsNotSatisfied)
5476 *ConstraintsNotSatisfied = false;
5478 // Make a copy of the template arguments for processing. Only make the
5479 // changes at the end when successful in matching the arguments to the
5481 TemplateArgumentListInfo NewArgs = TemplateArgs;
5483 // Make sure we get the template parameter list from the most
5484 // recentdeclaration, since that is the only one that has is guaranteed to
5485 // have all the default template argument information.
5486 TemplateParameterList *Params =
5487 cast<TemplateDecl>(Template->getMostRecentDecl())
5488 ->getTemplateParameters();
5490 SourceLocation RAngleLoc = NewArgs.getRAngleLoc();
5492 // C++ [temp.arg]p1:
5493 // [...] The type and form of each template-argument specified in
5494 // a template-id shall match the type and form specified for the
5495 // corresponding parameter declared by the template in its
5496 // template-parameter-list.
5497 bool isTemplateTemplateParameter = isa<TemplateTemplateParmDecl>(Template);
5498 SmallVector<TemplateArgument, 2> ArgumentPack;
5499 unsigned ArgIdx = 0, NumArgs = NewArgs.size();
5500 LocalInstantiationScope InstScope(*this, true);
5501 for (TemplateParameterList::iterator Param = Params->begin(),
5502 ParamEnd = Params->end();
5503 Param != ParamEnd; /* increment in loop */) {
5504 // If we have an expanded parameter pack, make sure we don't have too
5506 if (Optional<unsigned> Expansions = getExpandedPackSize(*Param)) {
5507 if (*Expansions == ArgumentPack.size()) {
5508 // We're done with this parameter pack. Pack up its arguments and add
5509 // them to the list.
5510 Converted.push_back(
5511 TemplateArgument::CreatePackCopy(Context, ArgumentPack));
5512 ArgumentPack.clear();
5514 // This argument is assigned to the next parameter.
5517 } else if (ArgIdx == NumArgs && !PartialTemplateArgs) {
5518 // Not enough arguments for this parameter pack.
5519 Diag(TemplateLoc, diag::err_template_arg_list_different_arity)
5520 << /*not enough args*/0
5521 << (int)getTemplateNameKindForDiagnostics(TemplateName(Template))
5523 Diag(Template->getLocation(), diag::note_template_decl_here)
5524 << Params->getSourceRange();
5529 if (ArgIdx < NumArgs) {
5530 // Check the template argument we were given.
5531 if (CheckTemplateArgument(*Param, NewArgs[ArgIdx], Template,
5532 TemplateLoc, RAngleLoc,
5533 ArgumentPack.size(), Converted))
5536 bool PackExpansionIntoNonPack =
5537 NewArgs[ArgIdx].getArgument().isPackExpansion() &&
5538 (!(*Param)->isTemplateParameterPack() || getExpandedPackSize(*Param));
5539 if (PackExpansionIntoNonPack && (isa<TypeAliasTemplateDecl>(Template) ||
5540 isa<ConceptDecl>(Template))) {
5541 // Core issue 1430: we have a pack expansion as an argument to an
5542 // alias template, and it's not part of a parameter pack. This
5543 // can't be canonicalized, so reject it now.
5544 // As for concepts - we cannot normalize constraints where this
5545 // situation exists.
5546 Diag(NewArgs[ArgIdx].getLocation(),
5547 diag::err_template_expansion_into_fixed_list)
5548 << (isa<ConceptDecl>(Template) ? 1 : 0)
5549 << NewArgs[ArgIdx].getSourceRange();
5550 Diag((*Param)->getLocation(), diag::note_template_param_here);
5554 // We're now done with this argument.
5557 if ((*Param)->isTemplateParameterPack()) {
5558 // The template parameter was a template parameter pack, so take the
5559 // deduced argument and place it on the argument pack. Note that we
5560 // stay on the same template parameter so that we can deduce more
5562 ArgumentPack.push_back(Converted.pop_back_val());
5564 // Move to the next template parameter.
5568 // If we just saw a pack expansion into a non-pack, then directly convert
5569 // the remaining arguments, because we don't know what parameters they'll
5571 if (PackExpansionIntoNonPack) {
5572 if (!ArgumentPack.empty()) {
5573 // If we were part way through filling in an expanded parameter pack,
5574 // fall back to just producing individual arguments.
5575 Converted.insert(Converted.end(),
5576 ArgumentPack.begin(), ArgumentPack.end());
5577 ArgumentPack.clear();
5580 while (ArgIdx < NumArgs) {
5581 Converted.push_back(NewArgs[ArgIdx].getArgument());
5591 // If we're checking a partial template argument list, we're done.
5592 if (PartialTemplateArgs) {
5593 if ((*Param)->isTemplateParameterPack() && !ArgumentPack.empty())
5594 Converted.push_back(
5595 TemplateArgument::CreatePackCopy(Context, ArgumentPack));
5599 // If we have a template parameter pack with no more corresponding
5600 // arguments, just break out now and we'll fill in the argument pack below.
5601 if ((*Param)->isTemplateParameterPack()) {
5602 assert(!getExpandedPackSize(*Param) &&
5603 "Should have dealt with this already");
5605 // A non-expanded parameter pack before the end of the parameter list
5606 // only occurs for an ill-formed template parameter list, unless we've
5607 // got a partial argument list for a function template, so just bail out.
5608 if (Param + 1 != ParamEnd)
5611 Converted.push_back(
5612 TemplateArgument::CreatePackCopy(Context, ArgumentPack));
5613 ArgumentPack.clear();
5619 // Check whether we have a default argument.
5620 TemplateArgumentLoc Arg;
5622 // Retrieve the default template argument from the template
5623 // parameter. For each kind of template parameter, we substitute the
5624 // template arguments provided thus far and any "outer" template arguments
5625 // (when the template parameter was part of a nested template) into
5626 // the default argument.
5627 if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(*Param)) {
5628 if (!hasVisibleDefaultArgument(TTP))
5629 return diagnoseMissingArgument(*this, TemplateLoc, Template, TTP,
5632 TypeSourceInfo *ArgType = SubstDefaultTemplateArgument(*this,
5641 Arg = TemplateArgumentLoc(TemplateArgument(ArgType->getType()),
5643 } else if (NonTypeTemplateParmDecl *NTTP
5644 = dyn_cast<NonTypeTemplateParmDecl>(*Param)) {
5645 if (!hasVisibleDefaultArgument(NTTP))
5646 return diagnoseMissingArgument(*this, TemplateLoc, Template, NTTP,
5649 ExprResult E = SubstDefaultTemplateArgument(*this, Template,
5657 Expr *Ex = E.getAs<Expr>();
5658 Arg = TemplateArgumentLoc(TemplateArgument(Ex), Ex);
5660 TemplateTemplateParmDecl *TempParm
5661 = cast<TemplateTemplateParmDecl>(*Param);
5663 if (!hasVisibleDefaultArgument(TempParm))
5664 return diagnoseMissingArgument(*this, TemplateLoc, Template, TempParm,
5667 NestedNameSpecifierLoc QualifierLoc;
5668 TemplateName Name = SubstDefaultTemplateArgument(*this, Template,
5677 Arg = TemplateArgumentLoc(TemplateArgument(Name), QualifierLoc,
5678 TempParm->getDefaultArgument().getTemplateNameLoc());
5681 // Introduce an instantiation record that describes where we are using
5682 // the default template argument. We're not actually instantiating a
5683 // template here, we just create this object to put a note into the
5685 InstantiatingTemplate Inst(*this, RAngleLoc, Template, *Param, Converted,
5686 SourceRange(TemplateLoc, RAngleLoc));
5687 if (Inst.isInvalid())
5690 // Check the default template argument.
5691 if (CheckTemplateArgument(*Param, Arg, Template, TemplateLoc,
5692 RAngleLoc, 0, Converted))
5695 // Core issue 150 (assumed resolution): if this is a template template
5696 // parameter, keep track of the default template arguments from the
5697 // template definition.
5698 if (isTemplateTemplateParameter)
5699 NewArgs.addArgument(Arg);
5701 // Move to the next template parameter and argument.
5706 // If we're performing a partial argument substitution, allow any trailing
5707 // pack expansions; they might be empty. This can happen even if
5708 // PartialTemplateArgs is false (the list of arguments is complete but
5709 // still dependent).
5710 if (ArgIdx < NumArgs && CurrentInstantiationScope &&
5711 CurrentInstantiationScope->getPartiallySubstitutedPack()) {
5712 while (ArgIdx < NumArgs && NewArgs[ArgIdx].getArgument().isPackExpansion())
5713 Converted.push_back(NewArgs[ArgIdx++].getArgument());
5716 // If we have any leftover arguments, then there were too many arguments.
5717 // Complain and fail.
5718 if (ArgIdx < NumArgs) {
5719 Diag(TemplateLoc, diag::err_template_arg_list_different_arity)
5720 << /*too many args*/1
5721 << (int)getTemplateNameKindForDiagnostics(TemplateName(Template))
5723 << SourceRange(NewArgs[ArgIdx].getLocation(), NewArgs.getRAngleLoc());
5724 Diag(Template->getLocation(), diag::note_template_decl_here)
5725 << Params->getSourceRange();
5729 // No problems found with the new argument list, propagate changes back
5731 if (UpdateArgsWithConversions)
5732 TemplateArgs = std::move(NewArgs);
5734 if (!PartialTemplateArgs &&
5735 EnsureTemplateArgumentListConstraints(
5736 Template, Converted, SourceRange(TemplateLoc,
5737 TemplateArgs.getRAngleLoc()))) {
5738 if (ConstraintsNotSatisfied)
5739 *ConstraintsNotSatisfied = true;
5747 class UnnamedLocalNoLinkageFinder
5748 : public TypeVisitor<UnnamedLocalNoLinkageFinder, bool>
5753 typedef TypeVisitor<UnnamedLocalNoLinkageFinder, bool> inherited;
5756 UnnamedLocalNoLinkageFinder(Sema &S, SourceRange SR) : S(S), SR(SR) { }
5758 bool Visit(QualType T) {
5759 return T.isNull() ? false : inherited::Visit(T.getTypePtr());
5762 #define TYPE(Class, Parent) \
5763 bool Visit##Class##Type(const Class##Type *);
5764 #define ABSTRACT_TYPE(Class, Parent) \
5765 bool Visit##Class##Type(const Class##Type *) { return false; }
5766 #define NON_CANONICAL_TYPE(Class, Parent) \
5767 bool Visit##Class##Type(const Class##Type *) { return false; }
5768 #include "clang/AST/TypeNodes.inc"
5770 bool VisitTagDecl(const TagDecl *Tag);
5771 bool VisitNestedNameSpecifier(NestedNameSpecifier *NNS);
5773 } // end anonymous namespace
5775 bool UnnamedLocalNoLinkageFinder::VisitBuiltinType(const BuiltinType*) {
5779 bool UnnamedLocalNoLinkageFinder::VisitComplexType(const ComplexType* T) {
5780 return Visit(T->getElementType());
5783 bool UnnamedLocalNoLinkageFinder::VisitPointerType(const PointerType* T) {
5784 return Visit(T->getPointeeType());
5787 bool UnnamedLocalNoLinkageFinder::VisitBlockPointerType(
5788 const BlockPointerType* T) {
5789 return Visit(T->getPointeeType());
5792 bool UnnamedLocalNoLinkageFinder::VisitLValueReferenceType(
5793 const LValueReferenceType* T) {
5794 return Visit(T->getPointeeType());
5797 bool UnnamedLocalNoLinkageFinder::VisitRValueReferenceType(
5798 const RValueReferenceType* T) {
5799 return Visit(T->getPointeeType());
5802 bool UnnamedLocalNoLinkageFinder::VisitMemberPointerType(
5803 const MemberPointerType* T) {
5804 return Visit(T->getPointeeType()) || Visit(QualType(T->getClass(), 0));
5807 bool UnnamedLocalNoLinkageFinder::VisitConstantArrayType(
5808 const ConstantArrayType* T) {
5809 return Visit(T->getElementType());
5812 bool UnnamedLocalNoLinkageFinder::VisitIncompleteArrayType(
5813 const IncompleteArrayType* T) {
5814 return Visit(T->getElementType());
5817 bool UnnamedLocalNoLinkageFinder::VisitVariableArrayType(
5818 const VariableArrayType* T) {
5819 return Visit(T->getElementType());
5822 bool UnnamedLocalNoLinkageFinder::VisitDependentSizedArrayType(
5823 const DependentSizedArrayType* T) {
5824 return Visit(T->getElementType());
5827 bool UnnamedLocalNoLinkageFinder::VisitDependentSizedExtVectorType(
5828 const DependentSizedExtVectorType* T) {
5829 return Visit(T->getElementType());
5832 bool UnnamedLocalNoLinkageFinder::VisitDependentAddressSpaceType(
5833 const DependentAddressSpaceType *T) {
5834 return Visit(T->getPointeeType());
5837 bool UnnamedLocalNoLinkageFinder::VisitVectorType(const VectorType* T) {
5838 return Visit(T->getElementType());
5841 bool UnnamedLocalNoLinkageFinder::VisitDependentVectorType(
5842 const DependentVectorType *T) {
5843 return Visit(T->getElementType());
5846 bool UnnamedLocalNoLinkageFinder::VisitExtVectorType(const ExtVectorType* T) {
5847 return Visit(T->getElementType());
5850 bool UnnamedLocalNoLinkageFinder::VisitFunctionProtoType(
5851 const FunctionProtoType* T) {
5852 for (const auto &A : T->param_types()) {
5857 return Visit(T->getReturnType());
5860 bool UnnamedLocalNoLinkageFinder::VisitFunctionNoProtoType(
5861 const FunctionNoProtoType* T) {
5862 return Visit(T->getReturnType());
5865 bool UnnamedLocalNoLinkageFinder::VisitUnresolvedUsingType(
5866 const UnresolvedUsingType*) {
5870 bool UnnamedLocalNoLinkageFinder::VisitTypeOfExprType(const TypeOfExprType*) {
5874 bool UnnamedLocalNoLinkageFinder::VisitTypeOfType(const TypeOfType* T) {
5875 return Visit(T->getUnderlyingType());
5878 bool UnnamedLocalNoLinkageFinder::VisitDecltypeType(const DecltypeType*) {
5882 bool UnnamedLocalNoLinkageFinder::VisitUnaryTransformType(
5883 const UnaryTransformType*) {
5887 bool UnnamedLocalNoLinkageFinder::VisitAutoType(const AutoType *T) {
5888 return Visit(T->getDeducedType());
5891 bool UnnamedLocalNoLinkageFinder::VisitDeducedTemplateSpecializationType(
5892 const DeducedTemplateSpecializationType *T) {
5893 return Visit(T->getDeducedType());
5896 bool UnnamedLocalNoLinkageFinder::VisitRecordType(const RecordType* T) {
5897 return VisitTagDecl(T->getDecl());
5900 bool UnnamedLocalNoLinkageFinder::VisitEnumType(const EnumType* T) {
5901 return VisitTagDecl(T->getDecl());
5904 bool UnnamedLocalNoLinkageFinder::VisitTemplateTypeParmType(
5905 const TemplateTypeParmType*) {
5909 bool UnnamedLocalNoLinkageFinder::VisitSubstTemplateTypeParmPackType(
5910 const SubstTemplateTypeParmPackType *) {
5914 bool UnnamedLocalNoLinkageFinder::VisitTemplateSpecializationType(
5915 const TemplateSpecializationType*) {
5919 bool UnnamedLocalNoLinkageFinder::VisitInjectedClassNameType(
5920 const InjectedClassNameType* T) {
5921 return VisitTagDecl(T->getDecl());
5924 bool UnnamedLocalNoLinkageFinder::VisitDependentNameType(
5925 const DependentNameType* T) {
5926 return VisitNestedNameSpecifier(T->getQualifier());
5929 bool UnnamedLocalNoLinkageFinder::VisitDependentTemplateSpecializationType(
5930 const DependentTemplateSpecializationType* T) {
5931 if (auto *Q = T->getQualifier())
5932 return VisitNestedNameSpecifier(Q);
5936 bool UnnamedLocalNoLinkageFinder::VisitPackExpansionType(
5937 const PackExpansionType* T) {
5938 return Visit(T->getPattern());
5941 bool UnnamedLocalNoLinkageFinder::VisitObjCObjectType(const ObjCObjectType *) {
5945 bool UnnamedLocalNoLinkageFinder::VisitObjCInterfaceType(
5946 const ObjCInterfaceType *) {
5950 bool UnnamedLocalNoLinkageFinder::VisitObjCObjectPointerType(
5951 const ObjCObjectPointerType *) {
5955 bool UnnamedLocalNoLinkageFinder::VisitAtomicType(const AtomicType* T) {
5956 return Visit(T->getValueType());
5959 bool UnnamedLocalNoLinkageFinder::VisitPipeType(const PipeType* T) {
5963 bool UnnamedLocalNoLinkageFinder::VisitTagDecl(const TagDecl *Tag) {
5964 if (Tag->getDeclContext()->isFunctionOrMethod()) {
5965 S.Diag(SR.getBegin(),
5966 S.getLangOpts().CPlusPlus11 ?
5967 diag::warn_cxx98_compat_template_arg_local_type :
5968 diag::ext_template_arg_local_type)
5969 << S.Context.getTypeDeclType(Tag) << SR;
5973 if (!Tag->hasNameForLinkage()) {
5974 S.Diag(SR.getBegin(),
5975 S.getLangOpts().CPlusPlus11 ?
5976 diag::warn_cxx98_compat_template_arg_unnamed_type :
5977 diag::ext_template_arg_unnamed_type) << SR;
5978 S.Diag(Tag->getLocation(), diag::note_template_unnamed_type_here);
5985 bool UnnamedLocalNoLinkageFinder::VisitNestedNameSpecifier(
5986 NestedNameSpecifier *NNS) {
5988 if (NNS->getPrefix() && VisitNestedNameSpecifier(NNS->getPrefix()))
5991 switch (NNS->getKind()) {
5992 case NestedNameSpecifier::Identifier:
5993 case NestedNameSpecifier::Namespace:
5994 case NestedNameSpecifier::NamespaceAlias:
5995 case NestedNameSpecifier::Global:
5996 case NestedNameSpecifier::Super:
5999 case NestedNameSpecifier::TypeSpec:
6000 case NestedNameSpecifier::TypeSpecWithTemplate:
6001 return Visit(QualType(NNS->getAsType(), 0));
6003 llvm_unreachable("Invalid NestedNameSpecifier::Kind!");
6006 /// Check a template argument against its corresponding
6007 /// template type parameter.
6009 /// This routine implements the semantics of C++ [temp.arg.type]. It
6010 /// returns true if an error occurred, and false otherwise.
6011 bool Sema::CheckTemplateArgument(TemplateTypeParmDecl *Param,
6012 TypeSourceInfo *ArgInfo) {
6013 assert(ArgInfo && "invalid TypeSourceInfo");
6014 QualType Arg = ArgInfo->getType();
6015 SourceRange SR = ArgInfo->getTypeLoc().getSourceRange();
6017 if (Arg->isVariablyModifiedType()) {
6018 return Diag(SR.getBegin(), diag::err_variably_modified_template_arg) << Arg;
6019 } else if (Context.hasSameUnqualifiedType(Arg, Context.OverloadTy)) {
6020 return Diag(SR.getBegin(), diag::err_template_arg_overload_type) << SR;
6023 // C++03 [temp.arg.type]p2:
6024 // A local type, a type with no linkage, an unnamed type or a type
6025 // compounded from any of these types shall not be used as a
6026 // template-argument for a template type-parameter.
6028 // C++11 allows these, and even in C++03 we allow them as an extension with
6030 if (LangOpts.CPlusPlus11 || Arg->hasUnnamedOrLocalType()) {
6031 UnnamedLocalNoLinkageFinder Finder(*this, SR);
6032 (void)Finder.Visit(Context.getCanonicalType(Arg));
6038 enum NullPointerValueKind {
6044 /// Determine whether the given template argument is a null pointer
6045 /// value of the appropriate type.
6046 static NullPointerValueKind
6047 isNullPointerValueTemplateArgument(Sema &S, NonTypeTemplateParmDecl *Param,
6048 QualType ParamType, Expr *Arg,
6049 Decl *Entity = nullptr) {
6050 if (Arg->isValueDependent() || Arg->isTypeDependent())
6051 return NPV_NotNullPointer;
6053 // dllimport'd entities aren't constant but are available inside of template
6055 if (Entity && Entity->hasAttr<DLLImportAttr>())
6056 return NPV_NotNullPointer;
6058 if (!S.isCompleteType(Arg->getExprLoc(), ParamType))
6060 "Incomplete parameter type in isNullPointerValueTemplateArgument!");
6062 if (!S.getLangOpts().CPlusPlus11)
6063 return NPV_NotNullPointer;
6065 // Determine whether we have a constant expression.
6066 ExprResult ArgRV = S.DefaultFunctionArrayConversion(Arg);
6067 if (ArgRV.isInvalid())
6071 Expr::EvalResult EvalResult;
6072 SmallVector<PartialDiagnosticAt, 8> Notes;
6073 EvalResult.Diag = &Notes;
6074 if (!Arg->EvaluateAsRValue(EvalResult, S.Context) ||
6075 EvalResult.HasSideEffects) {
6076 SourceLocation DiagLoc = Arg->getExprLoc();
6078 // If our only note is the usual "invalid subexpression" note, just point
6079 // the caret at its location rather than producing an essentially
6081 if (Notes.size() == 1 && Notes[0].second.getDiagID() ==
6082 diag::note_invalid_subexpr_in_const_expr) {
6083 DiagLoc = Notes[0].first;
6087 S.Diag(DiagLoc, diag::err_template_arg_not_address_constant)
6088 << Arg->getType() << Arg->getSourceRange();
6089 for (unsigned I = 0, N = Notes.size(); I != N; ++I)
6090 S.Diag(Notes[I].first, Notes[I].second);
6092 S.Diag(Param->getLocation(), diag::note_template_param_here);
6096 // C++11 [temp.arg.nontype]p1:
6097 // - an address constant expression of type std::nullptr_t
6098 if (Arg->getType()->isNullPtrType())
6099 return NPV_NullPointer;
6101 // - a constant expression that evaluates to a null pointer value (4.10); or
6102 // - a constant expression that evaluates to a null member pointer value
6104 if ((EvalResult.Val.isLValue() && !EvalResult.Val.getLValueBase()) ||
6105 (EvalResult.Val.isMemberPointer() &&
6106 !EvalResult.Val.getMemberPointerDecl())) {
6107 // If our expression has an appropriate type, we've succeeded.
6108 bool ObjCLifetimeConversion;
6109 if (S.Context.hasSameUnqualifiedType(Arg->getType(), ParamType) ||
6110 S.IsQualificationConversion(Arg->getType(), ParamType, false,
6111 ObjCLifetimeConversion))
6112 return NPV_NullPointer;
6114 // The types didn't match, but we know we got a null pointer; complain,
6115 // then recover as if the types were correct.
6116 S.Diag(Arg->getExprLoc(), diag::err_template_arg_wrongtype_null_constant)
6117 << Arg->getType() << ParamType << Arg->getSourceRange();
6118 S.Diag(Param->getLocation(), diag::note_template_param_here);
6119 return NPV_NullPointer;
6122 // If we don't have a null pointer value, but we do have a NULL pointer
6123 // constant, suggest a cast to the appropriate type.
6124 if (Arg->isNullPointerConstant(S.Context, Expr::NPC_NeverValueDependent)) {
6125 std::string Code = "static_cast<" + ParamType.getAsString() + ">(";
6126 S.Diag(Arg->getExprLoc(), diag::err_template_arg_untyped_null_constant)
6127 << ParamType << FixItHint::CreateInsertion(Arg->getBeginLoc(), Code)
6128 << FixItHint::CreateInsertion(S.getLocForEndOfToken(Arg->getEndLoc()),
6130 S.Diag(Param->getLocation(), diag::note_template_param_here);
6131 return NPV_NullPointer;
6134 // FIXME: If we ever want to support general, address-constant expressions
6135 // as non-type template arguments, we should return the ExprResult here to
6136 // be interpreted by the caller.
6137 return NPV_NotNullPointer;
6140 /// Checks whether the given template argument is compatible with its
6141 /// template parameter.
6142 static bool CheckTemplateArgumentIsCompatibleWithParameter(
6143 Sema &S, NonTypeTemplateParmDecl *Param, QualType ParamType, Expr *ArgIn,
6144 Expr *Arg, QualType ArgType) {
6145 bool ObjCLifetimeConversion;
6146 if (ParamType->isPointerType() &&
6147 !ParamType->castAs<PointerType>()->getPointeeType()->isFunctionType() &&
6148 S.IsQualificationConversion(ArgType, ParamType, false,
6149 ObjCLifetimeConversion)) {
6150 // For pointer-to-object types, qualification conversions are
6153 if (const ReferenceType *ParamRef = ParamType->getAs<ReferenceType>()) {
6154 if (!ParamRef->getPointeeType()->isFunctionType()) {
6155 // C++ [temp.arg.nontype]p5b3:
6156 // For a non-type template-parameter of type reference to
6157 // object, no conversions apply. The type referred to by the
6158 // reference may be more cv-qualified than the (otherwise
6159 // identical) type of the template- argument. The
6160 // template-parameter is bound directly to the
6161 // template-argument, which shall be an lvalue.
6163 // FIXME: Other qualifiers?
6164 unsigned ParamQuals = ParamRef->getPointeeType().getCVRQualifiers();
6165 unsigned ArgQuals = ArgType.getCVRQualifiers();
6167 if ((ParamQuals | ArgQuals) != ParamQuals) {
6168 S.Diag(Arg->getBeginLoc(),
6169 diag::err_template_arg_ref_bind_ignores_quals)
6170 << ParamType << Arg->getType() << Arg->getSourceRange();
6171 S.Diag(Param->getLocation(), diag::note_template_param_here);
6177 // At this point, the template argument refers to an object or
6178 // function with external linkage. We now need to check whether the
6179 // argument and parameter types are compatible.
6180 if (!S.Context.hasSameUnqualifiedType(ArgType,
6181 ParamType.getNonReferenceType())) {
6182 // We can't perform this conversion or binding.
6183 if (ParamType->isReferenceType())
6184 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_no_ref_bind)
6185 << ParamType << ArgIn->getType() << Arg->getSourceRange();
6187 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_not_convertible)
6188 << ArgIn->getType() << ParamType << Arg->getSourceRange();
6189 S.Diag(Param->getLocation(), diag::note_template_param_here);
6197 /// Checks whether the given template argument is the address
6198 /// of an object or function according to C++ [temp.arg.nontype]p1.
6200 CheckTemplateArgumentAddressOfObjectOrFunction(Sema &S,
6201 NonTypeTemplateParmDecl *Param,
6204 TemplateArgument &Converted) {
6205 bool Invalid = false;
6207 QualType ArgType = Arg->getType();
6209 bool AddressTaken = false;
6210 SourceLocation AddrOpLoc;
6211 if (S.getLangOpts().MicrosoftExt) {
6212 // Microsoft Visual C++ strips all casts, allows an arbitrary number of
6213 // dereference and address-of operators.
6214 Arg = Arg->IgnoreParenCasts();
6216 bool ExtWarnMSTemplateArg = false;
6217 UnaryOperatorKind FirstOpKind;
6218 SourceLocation FirstOpLoc;
6219 while (UnaryOperator *UnOp = dyn_cast<UnaryOperator>(Arg)) {
6220 UnaryOperatorKind UnOpKind = UnOp->getOpcode();
6221 if (UnOpKind == UO_Deref)
6222 ExtWarnMSTemplateArg = true;
6223 if (UnOpKind == UO_AddrOf || UnOpKind == UO_Deref) {
6224 Arg = UnOp->getSubExpr()->IgnoreParenCasts();
6225 if (!AddrOpLoc.isValid()) {
6226 FirstOpKind = UnOpKind;
6227 FirstOpLoc = UnOp->getOperatorLoc();
6232 if (FirstOpLoc.isValid()) {
6233 if (ExtWarnMSTemplateArg)
6234 S.Diag(ArgIn->getBeginLoc(), diag::ext_ms_deref_template_argument)
6235 << ArgIn->getSourceRange();
6237 if (FirstOpKind == UO_AddrOf)
6238 AddressTaken = true;
6239 else if (Arg->getType()->isPointerType()) {
6240 // We cannot let pointers get dereferenced here, that is obviously not a
6241 // constant expression.
6242 assert(FirstOpKind == UO_Deref);
6243 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_not_decl_ref)
6244 << Arg->getSourceRange();
6248 // See through any implicit casts we added to fix the type.
6249 Arg = Arg->IgnoreImpCasts();
6251 // C++ [temp.arg.nontype]p1:
6253 // A template-argument for a non-type, non-template
6254 // template-parameter shall be one of: [...]
6256 // -- the address of an object or function with external
6257 // linkage, including function templates and function
6258 // template-ids but excluding non-static class members,
6259 // expressed as & id-expression where the & is optional if
6260 // the name refers to a function or array, or if the
6261 // corresponding template-parameter is a reference; or
6263 // In C++98/03 mode, give an extension warning on any extra parentheses.
6264 // See http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#773
6265 bool ExtraParens = false;
6266 while (ParenExpr *Parens = dyn_cast<ParenExpr>(Arg)) {
6267 if (!Invalid && !ExtraParens) {
6268 S.Diag(Arg->getBeginLoc(),
6269 S.getLangOpts().CPlusPlus11
6270 ? diag::warn_cxx98_compat_template_arg_extra_parens
6271 : diag::ext_template_arg_extra_parens)
6272 << Arg->getSourceRange();
6276 Arg = Parens->getSubExpr();
6279 while (SubstNonTypeTemplateParmExpr *subst =
6280 dyn_cast<SubstNonTypeTemplateParmExpr>(Arg))
6281 Arg = subst->getReplacement()->IgnoreImpCasts();
6283 if (UnaryOperator *UnOp = dyn_cast<UnaryOperator>(Arg)) {
6284 if (UnOp->getOpcode() == UO_AddrOf) {
6285 Arg = UnOp->getSubExpr();
6286 AddressTaken = true;
6287 AddrOpLoc = UnOp->getOperatorLoc();
6291 while (SubstNonTypeTemplateParmExpr *subst =
6292 dyn_cast<SubstNonTypeTemplateParmExpr>(Arg))
6293 Arg = subst->getReplacement()->IgnoreImpCasts();
6296 DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Arg);
6297 ValueDecl *Entity = DRE ? DRE->getDecl() : nullptr;
6299 // If our parameter has pointer type, check for a null template value.
6300 if (ParamType->isPointerType() || ParamType->isNullPtrType()) {
6301 switch (isNullPointerValueTemplateArgument(S, Param, ParamType, ArgIn,
6303 case NPV_NullPointer:
6304 S.Diag(Arg->getExprLoc(), diag::warn_cxx98_compat_template_arg_null);
6305 Converted = TemplateArgument(S.Context.getCanonicalType(ParamType),
6306 /*isNullPtr=*/true);
6312 case NPV_NotNullPointer:
6317 // Stop checking the precise nature of the argument if it is value dependent,
6318 // it should be checked when instantiated.
6319 if (Arg->isValueDependent()) {
6320 Converted = TemplateArgument(ArgIn);
6324 if (isa<CXXUuidofExpr>(Arg)) {
6325 if (CheckTemplateArgumentIsCompatibleWithParameter(S, Param, ParamType,
6326 ArgIn, Arg, ArgType))
6329 Converted = TemplateArgument(ArgIn);
6334 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_not_decl_ref)
6335 << Arg->getSourceRange();
6336 S.Diag(Param->getLocation(), diag::note_template_param_here);
6340 // Cannot refer to non-static data members
6341 if (isa<FieldDecl>(Entity) || isa<IndirectFieldDecl>(Entity)) {
6342 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_field)
6343 << Entity << Arg->getSourceRange();
6344 S.Diag(Param->getLocation(), diag::note_template_param_here);
6348 // Cannot refer to non-static member functions
6349 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Entity)) {
6350 if (!Method->isStatic()) {
6351 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_method)
6352 << Method << Arg->getSourceRange();
6353 S.Diag(Param->getLocation(), diag::note_template_param_here);
6358 FunctionDecl *Func = dyn_cast<FunctionDecl>(Entity);
6359 VarDecl *Var = dyn_cast<VarDecl>(Entity);
6361 // A non-type template argument must refer to an object or function.
6362 if (!Func && !Var) {
6363 // We found something, but we don't know specifically what it is.
6364 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_not_object_or_func)
6365 << Arg->getSourceRange();
6366 S.Diag(DRE->getDecl()->getLocation(), diag::note_template_arg_refers_here);
6370 // Address / reference template args must have external linkage in C++98.
6371 if (Entity->getFormalLinkage() == InternalLinkage) {
6372 S.Diag(Arg->getBeginLoc(),
6373 S.getLangOpts().CPlusPlus11
6374 ? diag::warn_cxx98_compat_template_arg_object_internal
6375 : diag::ext_template_arg_object_internal)
6376 << !Func << Entity << Arg->getSourceRange();
6377 S.Diag(Entity->getLocation(), diag::note_template_arg_internal_object)
6379 } else if (!Entity->hasLinkage()) {
6380 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_object_no_linkage)
6381 << !Func << Entity << Arg->getSourceRange();
6382 S.Diag(Entity->getLocation(), diag::note_template_arg_internal_object)
6388 // If the template parameter has pointer type, the function decays.
6389 if (ParamType->isPointerType() && !AddressTaken)
6390 ArgType = S.Context.getPointerType(Func->getType());
6391 else if (AddressTaken && ParamType->isReferenceType()) {
6392 // If we originally had an address-of operator, but the
6393 // parameter has reference type, complain and (if things look
6394 // like they will work) drop the address-of operator.
6395 if (!S.Context.hasSameUnqualifiedType(Func->getType(),
6396 ParamType.getNonReferenceType())) {
6397 S.Diag(AddrOpLoc, diag::err_template_arg_address_of_non_pointer)
6399 S.Diag(Param->getLocation(), diag::note_template_param_here);
6403 S.Diag(AddrOpLoc, diag::err_template_arg_address_of_non_pointer)
6405 << FixItHint::CreateRemoval(AddrOpLoc);
6406 S.Diag(Param->getLocation(), diag::note_template_param_here);
6408 ArgType = Func->getType();
6411 // A value of reference type is not an object.
6412 if (Var->getType()->isReferenceType()) {
6413 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_reference_var)
6414 << Var->getType() << Arg->getSourceRange();
6415 S.Diag(Param->getLocation(), diag::note_template_param_here);
6419 // A template argument must have static storage duration.
6420 if (Var->getTLSKind()) {
6421 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_thread_local)
6422 << Arg->getSourceRange();
6423 S.Diag(Var->getLocation(), diag::note_template_arg_refers_here);
6427 // If the template parameter has pointer type, we must have taken
6428 // the address of this object.
6429 if (ParamType->isReferenceType()) {
6431 // If we originally had an address-of operator, but the
6432 // parameter has reference type, complain and (if things look
6433 // like they will work) drop the address-of operator.
6434 if (!S.Context.hasSameUnqualifiedType(Var->getType(),
6435 ParamType.getNonReferenceType())) {
6436 S.Diag(AddrOpLoc, diag::err_template_arg_address_of_non_pointer)
6438 S.Diag(Param->getLocation(), diag::note_template_param_here);
6442 S.Diag(AddrOpLoc, diag::err_template_arg_address_of_non_pointer)
6444 << FixItHint::CreateRemoval(AddrOpLoc);
6445 S.Diag(Param->getLocation(), diag::note_template_param_here);
6447 ArgType = Var->getType();
6449 } else if (!AddressTaken && ParamType->isPointerType()) {
6450 if (Var->getType()->isArrayType()) {
6451 // Array-to-pointer decay.
6452 ArgType = S.Context.getArrayDecayedType(Var->getType());
6454 // If the template parameter has pointer type but the address of
6455 // this object was not taken, complain and (possibly) recover by
6456 // taking the address of the entity.
6457 ArgType = S.Context.getPointerType(Var->getType());
6458 if (!S.Context.hasSameUnqualifiedType(ArgType, ParamType)) {
6459 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_not_address_of)
6461 S.Diag(Param->getLocation(), diag::note_template_param_here);
6465 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_not_address_of)
6466 << ParamType << FixItHint::CreateInsertion(Arg->getBeginLoc(), "&");
6468 S.Diag(Param->getLocation(), diag::note_template_param_here);
6473 if (CheckTemplateArgumentIsCompatibleWithParameter(S, Param, ParamType, ArgIn,
6477 // Create the template argument.
6479 TemplateArgument(cast<ValueDecl>(Entity->getCanonicalDecl()), ParamType);
6480 S.MarkAnyDeclReferenced(Arg->getBeginLoc(), Entity, false);
6484 /// Checks whether the given template argument is a pointer to
6485 /// member constant according to C++ [temp.arg.nontype]p1.
6486 static bool CheckTemplateArgumentPointerToMember(Sema &S,
6487 NonTypeTemplateParmDecl *Param,
6490 TemplateArgument &Converted) {
6491 bool Invalid = false;
6493 Expr *Arg = ResultArg;
6494 bool ObjCLifetimeConversion;
6496 // C++ [temp.arg.nontype]p1:
6498 // A template-argument for a non-type, non-template
6499 // template-parameter shall be one of: [...]
6501 // -- a pointer to member expressed as described in 5.3.1.
6502 DeclRefExpr *DRE = nullptr;
6504 // In C++98/03 mode, give an extension warning on any extra parentheses.
6505 // See http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#773
6506 bool ExtraParens = false;
6507 while (ParenExpr *Parens = dyn_cast<ParenExpr>(Arg)) {
6508 if (!Invalid && !ExtraParens) {
6509 S.Diag(Arg->getBeginLoc(),
6510 S.getLangOpts().CPlusPlus11
6511 ? diag::warn_cxx98_compat_template_arg_extra_parens
6512 : diag::ext_template_arg_extra_parens)
6513 << Arg->getSourceRange();
6517 Arg = Parens->getSubExpr();
6520 while (SubstNonTypeTemplateParmExpr *subst =
6521 dyn_cast<SubstNonTypeTemplateParmExpr>(Arg))
6522 Arg = subst->getReplacement()->IgnoreImpCasts();
6524 // A pointer-to-member constant written &Class::member.
6525 if (UnaryOperator *UnOp = dyn_cast<UnaryOperator>(Arg)) {
6526 if (UnOp->getOpcode() == UO_AddrOf) {
6527 DRE = dyn_cast<DeclRefExpr>(UnOp->getSubExpr());
6528 if (DRE && !DRE->getQualifier())
6532 // A constant of pointer-to-member type.
6533 else if ((DRE = dyn_cast<DeclRefExpr>(Arg))) {
6534 ValueDecl *VD = DRE->getDecl();
6535 if (VD->getType()->isMemberPointerType()) {
6536 if (isa<NonTypeTemplateParmDecl>(VD)) {
6537 if (Arg->isTypeDependent() || Arg->isValueDependent()) {
6538 Converted = TemplateArgument(Arg);
6540 VD = cast<ValueDecl>(VD->getCanonicalDecl());
6541 Converted = TemplateArgument(VD, ParamType);
6550 ValueDecl *Entity = DRE ? DRE->getDecl() : nullptr;
6552 // Check for a null pointer value.
6553 switch (isNullPointerValueTemplateArgument(S, Param, ParamType, ResultArg,
6557 case NPV_NullPointer:
6558 S.Diag(ResultArg->getExprLoc(), diag::warn_cxx98_compat_template_arg_null);
6559 Converted = TemplateArgument(S.Context.getCanonicalType(ParamType),
6562 case NPV_NotNullPointer:
6566 if (S.IsQualificationConversion(ResultArg->getType(),
6567 ParamType.getNonReferenceType(), false,
6568 ObjCLifetimeConversion)) {
6569 ResultArg = S.ImpCastExprToType(ResultArg, ParamType, CK_NoOp,
6570 ResultArg->getValueKind())
6572 } else if (!S.Context.hasSameUnqualifiedType(
6573 ResultArg->getType(), ParamType.getNonReferenceType())) {
6574 // We can't perform this conversion.
6575 S.Diag(ResultArg->getBeginLoc(), diag::err_template_arg_not_convertible)
6576 << ResultArg->getType() << ParamType << ResultArg->getSourceRange();
6577 S.Diag(Param->getLocation(), diag::note_template_param_here);
6582 return S.Diag(Arg->getBeginLoc(),
6583 diag::err_template_arg_not_pointer_to_member_form)
6584 << Arg->getSourceRange();
6586 if (isa<FieldDecl>(DRE->getDecl()) ||
6587 isa<IndirectFieldDecl>(DRE->getDecl()) ||
6588 isa<CXXMethodDecl>(DRE->getDecl())) {
6589 assert((isa<FieldDecl>(DRE->getDecl()) ||
6590 isa<IndirectFieldDecl>(DRE->getDecl()) ||
6591 !cast<CXXMethodDecl>(DRE->getDecl())->isStatic()) &&
6592 "Only non-static member pointers can make it here");
6594 // Okay: this is the address of a non-static member, and therefore
6595 // a member pointer constant.
6596 if (Arg->isTypeDependent() || Arg->isValueDependent()) {
6597 Converted = TemplateArgument(Arg);
6599 ValueDecl *D = cast<ValueDecl>(DRE->getDecl()->getCanonicalDecl());
6600 Converted = TemplateArgument(D, ParamType);
6605 // We found something else, but we don't know specifically what it is.
6606 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_not_pointer_to_member_form)
6607 << Arg->getSourceRange();
6608 S.Diag(DRE->getDecl()->getLocation(), diag::note_template_arg_refers_here);
6612 /// Check a template argument against its corresponding
6613 /// non-type template parameter.
6615 /// This routine implements the semantics of C++ [temp.arg.nontype].
6616 /// If an error occurred, it returns ExprError(); otherwise, it
6617 /// returns the converted template argument. \p ParamType is the
6618 /// type of the non-type template parameter after it has been instantiated.
6619 ExprResult Sema::CheckTemplateArgument(NonTypeTemplateParmDecl *Param,
6620 QualType ParamType, Expr *Arg,
6621 TemplateArgument &Converted,
6622 CheckTemplateArgumentKind CTAK) {
6623 SourceLocation StartLoc = Arg->getBeginLoc();
6625 // If the parameter type somehow involves auto, deduce the type now.
6626 if (getLangOpts().CPlusPlus17 && ParamType->isUndeducedType()) {
6627 // During template argument deduction, we allow 'decltype(auto)' to
6628 // match an arbitrary dependent argument.
6629 // FIXME: The language rules don't say what happens in this case.
6630 // FIXME: We get an opaque dependent type out of decltype(auto) if the
6631 // expression is merely instantiation-dependent; is this enough?
6632 if (CTAK == CTAK_Deduced && Arg->isTypeDependent()) {
6633 auto *AT = dyn_cast<AutoType>(ParamType);
6634 if (AT && AT->isDecltypeAuto()) {
6635 Converted = TemplateArgument(Arg);
6640 // When checking a deduced template argument, deduce from its type even if
6641 // the type is dependent, in order to check the types of non-type template
6642 // arguments line up properly in partial ordering.
6643 Optional<unsigned> Depth = Param->getDepth() + 1;
6644 Expr *DeductionArg = Arg;
6645 if (auto *PE = dyn_cast<PackExpansionExpr>(DeductionArg))
6646 DeductionArg = PE->getPattern();
6648 Context.getTrivialTypeSourceInfo(ParamType, Param->getLocation()),
6649 DeductionArg, ParamType, Depth,
6650 // We do not check constraints right now because the
6651 // immediately-declared constraint of the auto type is also an
6652 // associated constraint, and will be checked along with the other
6653 // associated constraints after checking the template argument list.
6654 /*IgnoreConstraints=*/true) == DAR_Failed) {
6655 Diag(Arg->getExprLoc(),
6656 diag::err_non_type_template_parm_type_deduction_failure)
6657 << Param->getDeclName() << Param->getType() << Arg->getType()
6658 << Arg->getSourceRange();
6659 Diag(Param->getLocation(), diag::note_template_param_here);
6662 // CheckNonTypeTemplateParameterType will produce a diagnostic if there's
6663 // an error. The error message normally references the parameter
6664 // declaration, but here we'll pass the argument location because that's
6665 // where the parameter type is deduced.
6666 ParamType = CheckNonTypeTemplateParameterType(ParamType, Arg->getExprLoc());
6667 if (ParamType.isNull()) {
6668 Diag(Param->getLocation(), diag::note_template_param_here);
6673 // We should have already dropped all cv-qualifiers by now.
6674 assert(!ParamType.hasQualifiers() &&
6675 "non-type template parameter type cannot be qualified");
6677 if (CTAK == CTAK_Deduced &&
6678 !Context.hasSameType(ParamType.getNonLValueExprType(Context),
6680 // FIXME: If either type is dependent, we skip the check. This isn't
6681 // correct, since during deduction we're supposed to have replaced each
6682 // template parameter with some unique (non-dependent) placeholder.
6683 // FIXME: If the argument type contains 'auto', we carry on and fail the
6684 // type check in order to force specific types to be more specialized than
6685 // 'auto'. It's not clear how partial ordering with 'auto' is supposed to
6687 if ((ParamType->isDependentType() || Arg->isTypeDependent()) &&
6688 !Arg->getType()->getContainedAutoType()) {
6689 Converted = TemplateArgument(Arg);
6692 // FIXME: This attempts to implement C++ [temp.deduct.type]p17. Per DR1770,
6693 // we should actually be checking the type of the template argument in P,
6694 // not the type of the template argument deduced from A, against the
6695 // template parameter type.
6696 Diag(StartLoc, diag::err_deduced_non_type_template_arg_type_mismatch)
6698 << ParamType.getUnqualifiedType();
6699 Diag(Param->getLocation(), diag::note_template_param_here);
6703 // If either the parameter has a dependent type or the argument is
6704 // type-dependent, there's nothing we can check now. The argument only
6705 // contains an unexpanded pack during partial ordering, and there's
6706 // nothing more we can check in that case.
6707 if (ParamType->isDependentType() || Arg->isTypeDependent() ||
6708 Arg->containsUnexpandedParameterPack()) {
6709 // Force the argument to the type of the parameter to maintain invariants.
6710 auto *PE = dyn_cast<PackExpansionExpr>(Arg);
6712 Arg = PE->getPattern();
6713 ExprResult E = ImpCastExprToType(
6714 Arg, ParamType.getNonLValueExprType(Context), CK_Dependent,
6715 ParamType->isLValueReferenceType() ? VK_LValue :
6716 ParamType->isRValueReferenceType() ? VK_XValue : VK_RValue);
6720 // Recreate a pack expansion if we unwrapped one.
6722 PackExpansionExpr(E.get()->getType(), E.get(), PE->getEllipsisLoc(),
6723 PE->getNumExpansions());
6725 Converted = TemplateArgument(E.get());
6729 // The initialization of the parameter from the argument is
6730 // a constant-evaluated context.
6731 EnterExpressionEvaluationContext ConstantEvaluated(
6732 *this, Sema::ExpressionEvaluationContext::ConstantEvaluated);
6734 if (getLangOpts().CPlusPlus17) {
6735 // C++17 [temp.arg.nontype]p1:
6736 // A template-argument for a non-type template parameter shall be
6737 // a converted constant expression of the type of the template-parameter.
6739 ExprResult ArgResult = CheckConvertedConstantExpression(
6740 Arg, ParamType, Value, CCEK_TemplateArg);
6741 if (ArgResult.isInvalid())
6744 // For a value-dependent argument, CheckConvertedConstantExpression is
6745 // permitted (and expected) to be unable to determine a value.
6746 if (ArgResult.get()->isValueDependent()) {
6747 Converted = TemplateArgument(ArgResult.get());
6751 QualType CanonParamType = Context.getCanonicalType(ParamType);
6753 // Convert the APValue to a TemplateArgument.
6754 switch (Value.getKind()) {
6756 assert(ParamType->isNullPtrType());
6757 Converted = TemplateArgument(CanonParamType, /*isNullPtr*/true);
6759 case APValue::Indeterminate:
6760 llvm_unreachable("result of constant evaluation should be initialized");
6763 assert(ParamType->isIntegralOrEnumerationType());
6764 Converted = TemplateArgument(Context, Value.getInt(), CanonParamType);
6766 case APValue::MemberPointer: {
6767 assert(ParamType->isMemberPointerType());
6769 // FIXME: We need TemplateArgument representation and mangling for these.
6770 if (!Value.getMemberPointerPath().empty()) {
6771 Diag(Arg->getBeginLoc(),
6772 diag::err_template_arg_member_ptr_base_derived_not_supported)
6773 << Value.getMemberPointerDecl() << ParamType
6774 << Arg->getSourceRange();
6778 auto *VD = const_cast<ValueDecl*>(Value.getMemberPointerDecl());
6779 Converted = VD ? TemplateArgument(VD, CanonParamType)
6780 : TemplateArgument(CanonParamType, /*isNullPtr*/true);
6783 case APValue::LValue: {
6784 // For a non-type template-parameter of pointer or reference type,
6785 // the value of the constant expression shall not refer to
6786 assert(ParamType->isPointerType() || ParamType->isReferenceType() ||
6787 ParamType->isNullPtrType());
6788 // -- a temporary object
6789 // -- a string literal
6790 // -- the result of a typeid expression, or
6791 // -- a predefined __func__ variable
6792 APValue::LValueBase Base = Value.getLValueBase();
6793 auto *VD = const_cast<ValueDecl *>(Base.dyn_cast<const ValueDecl *>());
6795 auto *E = Base.dyn_cast<const Expr *>();
6796 if (E && isa<CXXUuidofExpr>(E)) {
6797 Converted = TemplateArgument(ArgResult.get()->IgnoreImpCasts());
6800 Diag(Arg->getBeginLoc(), diag::err_template_arg_not_decl_ref)
6801 << Arg->getSourceRange();
6805 if (Value.hasLValuePath() && Value.getLValuePath().size() == 1 &&
6806 VD && VD->getType()->isArrayType() &&
6807 Value.getLValuePath()[0].getAsArrayIndex() == 0 &&
6808 !Value.isLValueOnePastTheEnd() && ParamType->isPointerType()) {
6809 // Per defect report (no number yet):
6810 // ... other than a pointer to the first element of a complete array
6812 } else if (!Value.hasLValuePath() || Value.getLValuePath().size() ||
6813 Value.isLValueOnePastTheEnd()) {
6814 Diag(StartLoc, diag::err_non_type_template_arg_subobject)
6815 << Value.getAsString(Context, ParamType);
6818 assert((VD || !ParamType->isReferenceType()) &&
6819 "null reference should not be a constant expression");
6820 assert((!VD || !ParamType->isNullPtrType()) &&
6821 "non-null value of type nullptr_t?");
6822 Converted = VD ? TemplateArgument(VD, CanonParamType)
6823 : TemplateArgument(CanonParamType, /*isNullPtr*/true);
6826 case APValue::AddrLabelDiff:
6827 return Diag(StartLoc, diag::err_non_type_template_arg_addr_label_diff);
6828 case APValue::FixedPoint:
6829 case APValue::Float:
6830 case APValue::ComplexInt:
6831 case APValue::ComplexFloat:
6832 case APValue::Vector:
6833 case APValue::Array:
6834 case APValue::Struct:
6835 case APValue::Union:
6836 llvm_unreachable("invalid kind for template argument");
6839 return ArgResult.get();
6842 // C++ [temp.arg.nontype]p5:
6843 // The following conversions are performed on each expression used
6844 // as a non-type template-argument. If a non-type
6845 // template-argument cannot be converted to the type of the
6846 // corresponding template-parameter then the program is
6848 if (ParamType->isIntegralOrEnumerationType()) {
6850 // -- for a non-type template-parameter of integral or
6851 // enumeration type, conversions permitted in a converted
6852 // constant expression are applied.
6855 // -- for a non-type template-parameter of integral or
6856 // enumeration type, integral promotions (4.5) and integral
6857 // conversions (4.7) are applied.
6859 if (getLangOpts().CPlusPlus11) {
6860 // C++ [temp.arg.nontype]p1:
6861 // A template-argument for a non-type, non-template template-parameter
6864 // -- for a non-type template-parameter of integral or enumeration
6865 // type, a converted constant expression of the type of the
6866 // template-parameter; or
6868 ExprResult ArgResult =
6869 CheckConvertedConstantExpression(Arg, ParamType, Value,
6871 if (ArgResult.isInvalid())
6874 // We can't check arbitrary value-dependent arguments.
6875 if (ArgResult.get()->isValueDependent()) {
6876 Converted = TemplateArgument(ArgResult.get());
6880 // Widen the argument value to sizeof(parameter type). This is almost
6881 // always a no-op, except when the parameter type is bool. In
6882 // that case, this may extend the argument from 1 bit to 8 bits.
6883 QualType IntegerType = ParamType;
6884 if (const EnumType *Enum = IntegerType->getAs<EnumType>())
6885 IntegerType = Enum->getDecl()->getIntegerType();
6886 Value = Value.extOrTrunc(Context.getTypeSize(IntegerType));
6888 Converted = TemplateArgument(Context, Value,
6889 Context.getCanonicalType(ParamType));
6893 ExprResult ArgResult = DefaultLvalueConversion(Arg);
6894 if (ArgResult.isInvalid())
6896 Arg = ArgResult.get();
6898 QualType ArgType = Arg->getType();
6900 // C++ [temp.arg.nontype]p1:
6901 // A template-argument for a non-type, non-template
6902 // template-parameter shall be one of:
6904 // -- an integral constant-expression of integral or enumeration
6906 // -- the name of a non-type template-parameter; or
6908 if (!ArgType->isIntegralOrEnumerationType()) {
6909 Diag(Arg->getBeginLoc(), diag::err_template_arg_not_integral_or_enumeral)
6910 << ArgType << Arg->getSourceRange();
6911 Diag(Param->getLocation(), diag::note_template_param_here);
6913 } else if (!Arg->isValueDependent()) {
6914 class TmplArgICEDiagnoser : public VerifyICEDiagnoser {
6918 TmplArgICEDiagnoser(QualType T) : T(T) { }
6920 void diagnoseNotICE(Sema &S, SourceLocation Loc,
6921 SourceRange SR) override {
6922 S.Diag(Loc, diag::err_template_arg_not_ice) << T << SR;
6924 } Diagnoser(ArgType);
6926 Arg = VerifyIntegerConstantExpression(Arg, &Value, Diagnoser,
6932 // From here on out, all we care about is the unqualified form
6933 // of the argument type.
6934 ArgType = ArgType.getUnqualifiedType();
6936 // Try to convert the argument to the parameter's type.
6937 if (Context.hasSameType(ParamType, ArgType)) {
6938 // Okay: no conversion necessary
6939 } else if (ParamType->isBooleanType()) {
6940 // This is an integral-to-boolean conversion.
6941 Arg = ImpCastExprToType(Arg, ParamType, CK_IntegralToBoolean).get();
6942 } else if (IsIntegralPromotion(Arg, ArgType, ParamType) ||
6943 !ParamType->isEnumeralType()) {
6944 // This is an integral promotion or conversion.
6945 Arg = ImpCastExprToType(Arg, ParamType, CK_IntegralCast).get();
6947 // We can't perform this conversion.
6948 Diag(Arg->getBeginLoc(), diag::err_template_arg_not_convertible)
6949 << Arg->getType() << ParamType << Arg->getSourceRange();
6950 Diag(Param->getLocation(), diag::note_template_param_here);
6954 // Add the value of this argument to the list of converted
6955 // arguments. We use the bitwidth and signedness of the template
6957 if (Arg->isValueDependent()) {
6958 // The argument is value-dependent. Create a new
6959 // TemplateArgument with the converted expression.
6960 Converted = TemplateArgument(Arg);
6964 QualType IntegerType = Context.getCanonicalType(ParamType);
6965 if (const EnumType *Enum = IntegerType->getAs<EnumType>())
6966 IntegerType = Context.getCanonicalType(Enum->getDecl()->getIntegerType());
6968 if (ParamType->isBooleanType()) {
6969 // Value must be zero or one.
6971 unsigned AllowedBits = Context.getTypeSize(IntegerType);
6972 if (Value.getBitWidth() != AllowedBits)
6973 Value = Value.extOrTrunc(AllowedBits);
6974 Value.setIsSigned(IntegerType->isSignedIntegerOrEnumerationType());
6976 llvm::APSInt OldValue = Value;
6978 // Coerce the template argument's value to the value it will have
6979 // based on the template parameter's type.
6980 unsigned AllowedBits = Context.getTypeSize(IntegerType);
6981 if (Value.getBitWidth() != AllowedBits)
6982 Value = Value.extOrTrunc(AllowedBits);
6983 Value.setIsSigned(IntegerType->isSignedIntegerOrEnumerationType());
6985 // Complain if an unsigned parameter received a negative value.
6986 if (IntegerType->isUnsignedIntegerOrEnumerationType()
6987 && (OldValue.isSigned() && OldValue.isNegative())) {
6988 Diag(Arg->getBeginLoc(), diag::warn_template_arg_negative)
6989 << OldValue.toString(10) << Value.toString(10) << Param->getType()
6990 << Arg->getSourceRange();
6991 Diag(Param->getLocation(), diag::note_template_param_here);
6994 // Complain if we overflowed the template parameter's type.
6995 unsigned RequiredBits;
6996 if (IntegerType->isUnsignedIntegerOrEnumerationType())
6997 RequiredBits = OldValue.getActiveBits();
6998 else if (OldValue.isUnsigned())
6999 RequiredBits = OldValue.getActiveBits() + 1;
7001 RequiredBits = OldValue.getMinSignedBits();
7002 if (RequiredBits > AllowedBits) {
7003 Diag(Arg->getBeginLoc(), diag::warn_template_arg_too_large)
7004 << OldValue.toString(10) << Value.toString(10) << Param->getType()
7005 << Arg->getSourceRange();
7006 Diag(Param->getLocation(), diag::note_template_param_here);
7010 Converted = TemplateArgument(Context, Value,
7011 ParamType->isEnumeralType()
7012 ? Context.getCanonicalType(ParamType)
7017 QualType ArgType = Arg->getType();
7018 DeclAccessPair FoundResult; // temporary for ResolveOverloadedFunction
7020 // Handle pointer-to-function, reference-to-function, and
7021 // pointer-to-member-function all in (roughly) the same way.
7022 if (// -- For a non-type template-parameter of type pointer to
7023 // function, only the function-to-pointer conversion (4.3) is
7024 // applied. If the template-argument represents a set of
7025 // overloaded functions (or a pointer to such), the matching
7026 // function is selected from the set (13.4).
7027 (ParamType->isPointerType() &&
7028 ParamType->castAs<PointerType>()->getPointeeType()->isFunctionType()) ||
7029 // -- For a non-type template-parameter of type reference to
7030 // function, no conversions apply. If the template-argument
7031 // represents a set of overloaded functions, the matching
7032 // function is selected from the set (13.4).
7033 (ParamType->isReferenceType() &&
7034 ParamType->castAs<ReferenceType>()->getPointeeType()->isFunctionType()) ||
7035 // -- For a non-type template-parameter of type pointer to
7036 // member function, no conversions apply. If the
7037 // template-argument represents a set of overloaded member
7038 // functions, the matching member function is selected from
7040 (ParamType->isMemberPointerType() &&
7041 ParamType->castAs<MemberPointerType>()->getPointeeType()
7042 ->isFunctionType())) {
7044 if (Arg->getType() == Context.OverloadTy) {
7045 if (FunctionDecl *Fn = ResolveAddressOfOverloadedFunction(Arg, ParamType,
7048 if (DiagnoseUseOfDecl(Fn, Arg->getBeginLoc()))
7051 Arg = FixOverloadedFunctionReference(Arg, FoundResult, Fn);
7052 ArgType = Arg->getType();
7057 if (!ParamType->isMemberPointerType()) {
7058 if (CheckTemplateArgumentAddressOfObjectOrFunction(*this, Param,
7065 if (CheckTemplateArgumentPointerToMember(*this, Param, ParamType, Arg,
7071 if (ParamType->isPointerType()) {
7072 // -- for a non-type template-parameter of type pointer to
7073 // object, qualification conversions (4.4) and the
7074 // array-to-pointer conversion (4.2) are applied.
7075 // C++0x also allows a value of std::nullptr_t.
7076 assert(ParamType->getPointeeType()->isIncompleteOrObjectType() &&
7077 "Only object pointers allowed here");
7079 if (CheckTemplateArgumentAddressOfObjectOrFunction(*this, Param,
7086 if (const ReferenceType *ParamRefType = ParamType->getAs<ReferenceType>()) {
7087 // -- For a non-type template-parameter of type reference to
7088 // object, no conversions apply. The type referred to by the
7089 // reference may be more cv-qualified than the (otherwise
7090 // identical) type of the template-argument. The
7091 // template-parameter is bound directly to the
7092 // template-argument, which must be an lvalue.
7093 assert(ParamRefType->getPointeeType()->isIncompleteOrObjectType() &&
7094 "Only object references allowed here");
7096 if (Arg->getType() == Context.OverloadTy) {
7097 if (FunctionDecl *Fn = ResolveAddressOfOverloadedFunction(Arg,
7098 ParamRefType->getPointeeType(),
7101 if (DiagnoseUseOfDecl(Fn, Arg->getBeginLoc()))
7104 Arg = FixOverloadedFunctionReference(Arg, FoundResult, Fn);
7105 ArgType = Arg->getType();
7110 if (CheckTemplateArgumentAddressOfObjectOrFunction(*this, Param,
7117 // Deal with parameters of type std::nullptr_t.
7118 if (ParamType->isNullPtrType()) {
7119 if (Arg->isTypeDependent() || Arg->isValueDependent()) {
7120 Converted = TemplateArgument(Arg);
7124 switch (isNullPointerValueTemplateArgument(*this, Param, ParamType, Arg)) {
7125 case NPV_NotNullPointer:
7126 Diag(Arg->getExprLoc(), diag::err_template_arg_not_convertible)
7127 << Arg->getType() << ParamType;
7128 Diag(Param->getLocation(), diag::note_template_param_here);
7134 case NPV_NullPointer:
7135 Diag(Arg->getExprLoc(), diag::warn_cxx98_compat_template_arg_null);
7136 Converted = TemplateArgument(Context.getCanonicalType(ParamType),
7142 // -- For a non-type template-parameter of type pointer to data
7143 // member, qualification conversions (4.4) are applied.
7144 assert(ParamType->isMemberPointerType() && "Only pointers to members remain");
7146 if (CheckTemplateArgumentPointerToMember(*this, Param, ParamType, Arg,
7152 static void DiagnoseTemplateParameterListArityMismatch(
7153 Sema &S, TemplateParameterList *New, TemplateParameterList *Old,
7154 Sema::TemplateParameterListEqualKind Kind, SourceLocation TemplateArgLoc);
7156 /// Check a template argument against its corresponding
7157 /// template template parameter.
7159 /// This routine implements the semantics of C++ [temp.arg.template].
7160 /// It returns true if an error occurred, and false otherwise.
7161 bool Sema::CheckTemplateTemplateArgument(TemplateTemplateParmDecl *Param,
7162 TemplateParameterList *Params,
7163 TemplateArgumentLoc &Arg) {
7164 TemplateName Name = Arg.getArgument().getAsTemplateOrTemplatePattern();
7165 TemplateDecl *Template = Name.getAsTemplateDecl();
7167 // Any dependent template name is fine.
7168 assert(Name.isDependent() && "Non-dependent template isn't a declaration?");
7172 if (Template->isInvalidDecl())
7175 // C++0x [temp.arg.template]p1:
7176 // A template-argument for a template template-parameter shall be
7177 // the name of a class template or an alias template, expressed as an
7178 // id-expression. When the template-argument names a class template, only
7179 // primary class templates are considered when matching the
7180 // template template argument with the corresponding parameter;
7181 // partial specializations are not considered even if their
7182 // parameter lists match that of the template template parameter.
7184 // Note that we also allow template template parameters here, which
7185 // will happen when we are dealing with, e.g., class template
7186 // partial specializations.
7187 if (!isa<ClassTemplateDecl>(Template) &&
7188 !isa<TemplateTemplateParmDecl>(Template) &&
7189 !isa<TypeAliasTemplateDecl>(Template) &&
7190 !isa<BuiltinTemplateDecl>(Template)) {
7191 assert(isa<FunctionTemplateDecl>(Template) &&
7192 "Only function templates are possible here");
7193 Diag(Arg.getLocation(), diag::err_template_arg_not_valid_template);
7194 Diag(Template->getLocation(), diag::note_template_arg_refers_here_func)
7198 // C++1z [temp.arg.template]p3: (DR 150)
7199 // A template-argument matches a template template-parameter P when P
7200 // is at least as specialized as the template-argument A.
7201 // FIXME: We should enable RelaxedTemplateTemplateArgs by default as it is a
7202 // defect report resolution from C++17 and shouldn't be introduced by
7204 if (getLangOpts().RelaxedTemplateTemplateArgs) {
7205 // Quick check for the common case:
7206 // If P contains a parameter pack, then A [...] matches P if each of A's
7207 // template parameters matches the corresponding template parameter in
7208 // the template-parameter-list of P.
7209 if (TemplateParameterListsAreEqual(
7210 Template->getTemplateParameters(), Params, false,
7211 TPL_TemplateTemplateArgumentMatch, Arg.getLocation()) &&
7212 // If the argument has no associated constraints, then the parameter is
7213 // definitely at least as specialized as the argument.
7214 // Otherwise - we need a more thorough check.
7215 !Template->hasAssociatedConstraints())
7218 if (isTemplateTemplateParameterAtLeastAsSpecializedAs(Params, Template,
7219 Arg.getLocation())) {
7220 // C++2a[temp.func.order]p2
7221 // [...] If both deductions succeed, the partial ordering selects the
7222 // more constrained template as described by the rules in
7223 // [temp.constr.order].
7224 SmallVector<const Expr *, 3> ParamsAC, TemplateAC;
7225 Params->getAssociatedConstraints(ParamsAC);
7226 // C++2a[temp.arg.template]p3
7227 // [...] In this comparison, if P is unconstrained, the constraints on A
7228 // are not considered.
7229 if (ParamsAC.empty())
7231 Template->getAssociatedConstraints(TemplateAC);
7232 bool IsParamAtLeastAsConstrained;
7233 if (IsAtLeastAsConstrained(Param, ParamsAC, Template, TemplateAC,
7234 IsParamAtLeastAsConstrained))
7236 if (!IsParamAtLeastAsConstrained) {
7237 Diag(Arg.getLocation(),
7238 diag::err_template_template_parameter_not_at_least_as_constrained)
7239 << Template << Param << Arg.getSourceRange();
7240 Diag(Param->getLocation(), diag::note_entity_declared_at) << Param;
7241 Diag(Template->getLocation(), diag::note_entity_declared_at)
7243 MaybeEmitAmbiguousAtomicConstraintsDiagnostic(Param, ParamsAC, Template,
7249 // FIXME: Produce better diagnostics for deduction failures.
7252 return !TemplateParameterListsAreEqual(Template->getTemplateParameters(),
7255 TPL_TemplateTemplateArgumentMatch,
7259 /// Given a non-type template argument that refers to a
7260 /// declaration and the type of its corresponding non-type template
7261 /// parameter, produce an expression that properly refers to that
7264 Sema::BuildExpressionFromDeclTemplateArgument(const TemplateArgument &Arg,
7266 SourceLocation Loc) {
7267 // C++ [temp.param]p8:
7269 // A non-type template-parameter of type "array of T" or
7270 // "function returning T" is adjusted to be of type "pointer to
7271 // T" or "pointer to function returning T", respectively.
7272 if (ParamType->isArrayType())
7273 ParamType = Context.getArrayDecayedType(ParamType);
7274 else if (ParamType->isFunctionType())
7275 ParamType = Context.getPointerType(ParamType);
7277 // For a NULL non-type template argument, return nullptr casted to the
7278 // parameter's type.
7279 if (Arg.getKind() == TemplateArgument::NullPtr) {
7280 return ImpCastExprToType(
7281 new (Context) CXXNullPtrLiteralExpr(Context.NullPtrTy, Loc),
7283 ParamType->getAs<MemberPointerType>()
7284 ? CK_NullToMemberPointer
7285 : CK_NullToPointer);
7287 assert(Arg.getKind() == TemplateArgument::Declaration &&
7288 "Only declaration template arguments permitted here");
7290 ValueDecl *VD = Arg.getAsDecl();
7293 if (ParamType->isMemberPointerType()) {
7294 // If this is a pointer to member, we need to use a qualified name to
7295 // form a suitable pointer-to-member constant.
7296 assert(VD->getDeclContext()->isRecord() &&
7297 (isa<CXXMethodDecl>(VD) || isa<FieldDecl>(VD) ||
7298 isa<IndirectFieldDecl>(VD)));
7300 = Context.getTypeDeclType(cast<RecordDecl>(VD->getDeclContext()));
7301 NestedNameSpecifier *Qualifier
7302 = NestedNameSpecifier::Create(Context, nullptr, false,
7303 ClassType.getTypePtr());
7304 SS.MakeTrivial(Context, Qualifier, Loc);
7307 ExprResult RefExpr = BuildDeclarationNameExpr(
7308 SS, DeclarationNameInfo(VD->getDeclName(), Loc), VD);
7309 if (RefExpr.isInvalid())
7312 // For a pointer, the argument declaration is the pointee. Take its address.
7313 QualType ElemT(RefExpr.get()->getType()->getArrayElementTypeNoTypeQual(), 0);
7314 if (ParamType->isPointerType() && !ElemT.isNull() &&
7315 Context.hasSimilarType(ElemT, ParamType->getPointeeType())) {
7316 // Decay an array argument if we want a pointer to its first element.
7317 RefExpr = DefaultFunctionArrayConversion(RefExpr.get());
7318 if (RefExpr.isInvalid())
7320 } else if (ParamType->isPointerType() || ParamType->isMemberPointerType()) {
7321 // For any other pointer, take the address (or form a pointer-to-member).
7322 RefExpr = CreateBuiltinUnaryOp(Loc, UO_AddrOf, RefExpr.get());
7323 if (RefExpr.isInvalid())
7326 assert(ParamType->isReferenceType() &&
7327 "unexpected type for decl template argument");
7330 // At this point we should have the right value category.
7331 assert(ParamType->isReferenceType() == RefExpr.get()->isLValue() &&
7332 "value kind mismatch for non-type template argument");
7334 // The type of the template parameter can differ from the type of the
7335 // argument in various ways; convert it now if necessary.
7336 QualType DestExprType = ParamType.getNonLValueExprType(Context);
7337 if (!Context.hasSameType(RefExpr.get()->getType(), DestExprType)) {
7340 if (Context.hasSimilarType(RefExpr.get()->getType(), DestExprType) ||
7341 IsFunctionConversion(RefExpr.get()->getType(), DestExprType, Ignored)) {
7343 } else if (ParamType->isVoidPointerType() &&
7344 RefExpr.get()->getType()->isPointerType()) {
7347 // FIXME: Pointers to members can need conversion derived-to-base or
7348 // base-to-derived conversions. We currently don't retain enough
7349 // information to convert properly (we need to track a cast path or
7350 // subobject number in the template argument).
7352 "unexpected conversion required for non-type template argument");
7354 RefExpr = ImpCastExprToType(RefExpr.get(), DestExprType, CK,
7355 RefExpr.get()->getValueKind());
7361 /// Construct a new expression that refers to the given
7362 /// integral template argument with the given source-location
7365 /// This routine takes care of the mapping from an integral template
7366 /// argument (which may have any integral type) to the appropriate
7369 Sema::BuildExpressionFromIntegralTemplateArgument(const TemplateArgument &Arg,
7370 SourceLocation Loc) {
7371 assert(Arg.getKind() == TemplateArgument::Integral &&
7372 "Operation is only valid for integral template arguments");
7373 QualType OrigT = Arg.getIntegralType();
7375 // If this is an enum type that we're instantiating, we need to use an integer
7376 // type the same size as the enumerator. We don't want to build an
7377 // IntegerLiteral with enum type. The integer type of an enum type can be of
7378 // any integral type with C++11 enum classes, make sure we create the right
7379 // type of literal for it.
7381 if (const EnumType *ET = OrigT->getAs<EnumType>())
7382 T = ET->getDecl()->getIntegerType();
7385 if (T->isAnyCharacterType()) {
7386 CharacterLiteral::CharacterKind Kind;
7387 if (T->isWideCharType())
7388 Kind = CharacterLiteral::Wide;
7389 else if (T->isChar8Type() && getLangOpts().Char8)
7390 Kind = CharacterLiteral::UTF8;
7391 else if (T->isChar16Type())
7392 Kind = CharacterLiteral::UTF16;
7393 else if (T->isChar32Type())
7394 Kind = CharacterLiteral::UTF32;
7396 Kind = CharacterLiteral::Ascii;
7398 E = new (Context) CharacterLiteral(Arg.getAsIntegral().getZExtValue(),
7400 } else if (T->isBooleanType()) {
7401 E = new (Context) CXXBoolLiteralExpr(Arg.getAsIntegral().getBoolValue(),
7403 } else if (T->isNullPtrType()) {
7404 E = new (Context) CXXNullPtrLiteralExpr(Context.NullPtrTy, Loc);
7406 E = IntegerLiteral::Create(Context, Arg.getAsIntegral(), T, Loc);
7409 if (OrigT->isEnumeralType()) {
7410 // FIXME: This is a hack. We need a better way to handle substituted
7411 // non-type template parameters.
7412 E = CStyleCastExpr::Create(Context, OrigT, VK_RValue, CK_IntegralCast, E,
7414 Context.getTrivialTypeSourceInfo(OrigT, Loc),
7421 /// Match two template parameters within template parameter lists.
7422 static bool MatchTemplateParameterKind(Sema &S, NamedDecl *New, NamedDecl *Old,
7424 Sema::TemplateParameterListEqualKind Kind,
7425 SourceLocation TemplateArgLoc) {
7426 // Check the actual kind (type, non-type, template).
7427 if (Old->getKind() != New->getKind()) {
7429 unsigned NextDiag = diag::err_template_param_different_kind;
7430 if (TemplateArgLoc.isValid()) {
7431 S.Diag(TemplateArgLoc, diag::err_template_arg_template_params_mismatch);
7432 NextDiag = diag::note_template_param_different_kind;
7434 S.Diag(New->getLocation(), NextDiag)
7435 << (Kind != Sema::TPL_TemplateMatch);
7436 S.Diag(Old->getLocation(), diag::note_template_prev_declaration)
7437 << (Kind != Sema::TPL_TemplateMatch);
7443 // Check that both are parameter packs or neither are parameter packs.
7444 // However, if we are matching a template template argument to a
7445 // template template parameter, the template template parameter can have
7446 // a parameter pack where the template template argument does not.
7447 if (Old->isTemplateParameterPack() != New->isTemplateParameterPack() &&
7448 !(Kind == Sema::TPL_TemplateTemplateArgumentMatch &&
7449 Old->isTemplateParameterPack())) {
7451 unsigned NextDiag = diag::err_template_parameter_pack_non_pack;
7452 if (TemplateArgLoc.isValid()) {
7453 S.Diag(TemplateArgLoc,
7454 diag::err_template_arg_template_params_mismatch);
7455 NextDiag = diag::note_template_parameter_pack_non_pack;
7458 unsigned ParamKind = isa<TemplateTypeParmDecl>(New)? 0
7459 : isa<NonTypeTemplateParmDecl>(New)? 1
7461 S.Diag(New->getLocation(), NextDiag)
7462 << ParamKind << New->isParameterPack();
7463 S.Diag(Old->getLocation(), diag::note_template_parameter_pack_here)
7464 << ParamKind << Old->isParameterPack();
7470 // For non-type template parameters, check the type of the parameter.
7471 if (NonTypeTemplateParmDecl *OldNTTP
7472 = dyn_cast<NonTypeTemplateParmDecl>(Old)) {
7473 NonTypeTemplateParmDecl *NewNTTP = cast<NonTypeTemplateParmDecl>(New);
7475 // If we are matching a template template argument to a template
7476 // template parameter and one of the non-type template parameter types
7477 // is dependent, then we must wait until template instantiation time
7478 // to actually compare the arguments.
7479 if (Kind != Sema::TPL_TemplateTemplateArgumentMatch ||
7480 (!OldNTTP->getType()->isDependentType() &&
7481 !NewNTTP->getType()->isDependentType()))
7482 if (!S.Context.hasSameType(OldNTTP->getType(), NewNTTP->getType())) {
7484 unsigned NextDiag = diag::err_template_nontype_parm_different_type;
7485 if (TemplateArgLoc.isValid()) {
7486 S.Diag(TemplateArgLoc,
7487 diag::err_template_arg_template_params_mismatch);
7488 NextDiag = diag::note_template_nontype_parm_different_type;
7490 S.Diag(NewNTTP->getLocation(), NextDiag)
7491 << NewNTTP->getType()
7492 << (Kind != Sema::TPL_TemplateMatch);
7493 S.Diag(OldNTTP->getLocation(),
7494 diag::note_template_nontype_parm_prev_declaration)
7495 << OldNTTP->getType();
7501 // For template template parameters, check the template parameter types.
7502 // The template parameter lists of template template
7503 // parameters must agree.
7504 else if (TemplateTemplateParmDecl *OldTTP
7505 = dyn_cast<TemplateTemplateParmDecl>(Old)) {
7506 TemplateTemplateParmDecl *NewTTP = cast<TemplateTemplateParmDecl>(New);
7507 if (!S.TemplateParameterListsAreEqual(NewTTP->getTemplateParameters(),
7508 OldTTP->getTemplateParameters(),
7510 (Kind == Sema::TPL_TemplateMatch
7511 ? Sema::TPL_TemplateTemplateParmMatch
7515 } else if (Kind != Sema::TPL_TemplateTemplateArgumentMatch) {
7516 const Expr *NewC = nullptr, *OldC = nullptr;
7517 if (const auto *TC = cast<TemplateTypeParmDecl>(New)->getTypeConstraint())
7518 NewC = TC->getImmediatelyDeclaredConstraint();
7519 if (const auto *TC = cast<TemplateTypeParmDecl>(Old)->getTypeConstraint())
7520 OldC = TC->getImmediatelyDeclaredConstraint();
7522 auto Diagnose = [&] {
7523 S.Diag(NewC ? NewC->getBeginLoc() : New->getBeginLoc(),
7524 diag::err_template_different_type_constraint);
7525 S.Diag(OldC ? OldC->getBeginLoc() : Old->getBeginLoc(),
7526 diag::note_template_prev_declaration) << /*declaration*/0;
7529 if (!NewC != !OldC) {
7536 llvm::FoldingSetNodeID OldCID, NewCID;
7537 OldC->Profile(OldCID, S.Context, /*Canonical=*/true);
7538 NewC->Profile(NewCID, S.Context, /*Canonical=*/true);
7539 if (OldCID != NewCID) {
7550 /// Diagnose a known arity mismatch when comparing template argument
7553 void DiagnoseTemplateParameterListArityMismatch(Sema &S,
7554 TemplateParameterList *New,
7555 TemplateParameterList *Old,
7556 Sema::TemplateParameterListEqualKind Kind,
7557 SourceLocation TemplateArgLoc) {
7558 unsigned NextDiag = diag::err_template_param_list_different_arity;
7559 if (TemplateArgLoc.isValid()) {
7560 S.Diag(TemplateArgLoc, diag::err_template_arg_template_params_mismatch);
7561 NextDiag = diag::note_template_param_list_different_arity;
7563 S.Diag(New->getTemplateLoc(), NextDiag)
7564 << (New->size() > Old->size())
7565 << (Kind != Sema::TPL_TemplateMatch)
7566 << SourceRange(New->getTemplateLoc(), New->getRAngleLoc());
7567 S.Diag(Old->getTemplateLoc(), diag::note_template_prev_declaration)
7568 << (Kind != Sema::TPL_TemplateMatch)
7569 << SourceRange(Old->getTemplateLoc(), Old->getRAngleLoc());
7572 /// Determine whether the given template parameter lists are
7575 /// \param New The new template parameter list, typically written in the
7576 /// source code as part of a new template declaration.
7578 /// \param Old The old template parameter list, typically found via
7579 /// name lookup of the template declared with this template parameter
7582 /// \param Complain If true, this routine will produce a diagnostic if
7583 /// the template parameter lists are not equivalent.
7585 /// \param Kind describes how we are to match the template parameter lists.
7587 /// \param TemplateArgLoc If this source location is valid, then we
7588 /// are actually checking the template parameter list of a template
7589 /// argument (New) against the template parameter list of its
7590 /// corresponding template template parameter (Old). We produce
7591 /// slightly different diagnostics in this scenario.
7593 /// \returns True if the template parameter lists are equal, false
7596 Sema::TemplateParameterListsAreEqual(TemplateParameterList *New,
7597 TemplateParameterList *Old,
7599 TemplateParameterListEqualKind Kind,
7600 SourceLocation TemplateArgLoc) {
7601 if (Old->size() != New->size() && Kind != TPL_TemplateTemplateArgumentMatch) {
7603 DiagnoseTemplateParameterListArityMismatch(*this, New, Old, Kind,
7609 // C++0x [temp.arg.template]p3:
7610 // A template-argument matches a template template-parameter (call it P)
7611 // when each of the template parameters in the template-parameter-list of
7612 // the template-argument's corresponding class template or alias template
7613 // (call it A) matches the corresponding template parameter in the
7614 // template-parameter-list of P. [...]
7615 TemplateParameterList::iterator NewParm = New->begin();
7616 TemplateParameterList::iterator NewParmEnd = New->end();
7617 for (TemplateParameterList::iterator OldParm = Old->begin(),
7618 OldParmEnd = Old->end();
7619 OldParm != OldParmEnd; ++OldParm) {
7620 if (Kind != TPL_TemplateTemplateArgumentMatch ||
7621 !(*OldParm)->isTemplateParameterPack()) {
7622 if (NewParm == NewParmEnd) {
7624 DiagnoseTemplateParameterListArityMismatch(*this, New, Old, Kind,
7630 if (!MatchTemplateParameterKind(*this, *NewParm, *OldParm, Complain,
7631 Kind, TemplateArgLoc))
7638 // C++0x [temp.arg.template]p3:
7639 // [...] When P's template- parameter-list contains a template parameter
7640 // pack (14.5.3), the template parameter pack will match zero or more
7641 // template parameters or template parameter packs in the
7642 // template-parameter-list of A with the same type and form as the
7643 // template parameter pack in P (ignoring whether those template
7644 // parameters are template parameter packs).
7645 for (; NewParm != NewParmEnd; ++NewParm) {
7646 if (!MatchTemplateParameterKind(*this, *NewParm, *OldParm, Complain,
7647 Kind, TemplateArgLoc))
7652 // Make sure we exhausted all of the arguments.
7653 if (NewParm != NewParmEnd) {
7655 DiagnoseTemplateParameterListArityMismatch(*this, New, Old, Kind,
7661 if (Kind != TPL_TemplateTemplateArgumentMatch) {
7662 const Expr *NewRC = New->getRequiresClause();
7663 const Expr *OldRC = Old->getRequiresClause();
7665 auto Diagnose = [&] {
7666 Diag(NewRC ? NewRC->getBeginLoc() : New->getTemplateLoc(),
7667 diag::err_template_different_requires_clause);
7668 Diag(OldRC ? OldRC->getBeginLoc() : Old->getTemplateLoc(),
7669 diag::note_template_prev_declaration) << /*declaration*/0;
7672 if (!NewRC != !OldRC) {
7679 llvm::FoldingSetNodeID OldRCID, NewRCID;
7680 OldRC->Profile(OldRCID, Context, /*Canonical=*/true);
7681 NewRC->Profile(NewRCID, Context, /*Canonical=*/true);
7682 if (OldRCID != NewRCID) {
7693 /// Check whether a template can be declared within this scope.
7695 /// If the template declaration is valid in this scope, returns
7696 /// false. Otherwise, issues a diagnostic and returns true.
7698 Sema::CheckTemplateDeclScope(Scope *S, TemplateParameterList *TemplateParams) {
7702 // Find the nearest enclosing declaration scope.
7703 while ((S->getFlags() & Scope::DeclScope) == 0 ||
7704 (S->getFlags() & Scope::TemplateParamScope) != 0)
7708 // A template [...] shall not have C linkage.
7709 DeclContext *Ctx = S->getEntity();
7710 assert(Ctx && "Unknown context");
7711 if (Ctx->isExternCContext()) {
7712 Diag(TemplateParams->getTemplateLoc(), diag::err_template_linkage)
7713 << TemplateParams->getSourceRange();
7714 if (const LinkageSpecDecl *LSD = Ctx->getExternCContext())
7715 Diag(LSD->getExternLoc(), diag::note_extern_c_begins_here);
7718 Ctx = Ctx->getRedeclContext();
7721 // A template-declaration can appear only as a namespace scope or
7722 // class scope declaration.
7724 if (Ctx->isFileContext())
7726 if (CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(Ctx)) {
7727 // C++ [temp.mem]p2:
7728 // A local class shall not have member templates.
7729 if (RD->isLocalClass())
7730 return Diag(TemplateParams->getTemplateLoc(),
7731 diag::err_template_inside_local_class)
7732 << TemplateParams->getSourceRange();
7738 return Diag(TemplateParams->getTemplateLoc(),
7739 diag::err_template_outside_namespace_or_class_scope)
7740 << TemplateParams->getSourceRange();
7743 /// Determine what kind of template specialization the given declaration
7745 static TemplateSpecializationKind getTemplateSpecializationKind(Decl *D) {
7747 return TSK_Undeclared;
7749 if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(D))
7750 return Record->getTemplateSpecializationKind();
7751 if (FunctionDecl *Function = dyn_cast<FunctionDecl>(D))
7752 return Function->getTemplateSpecializationKind();
7753 if (VarDecl *Var = dyn_cast<VarDecl>(D))
7754 return Var->getTemplateSpecializationKind();
7756 return TSK_Undeclared;
7759 /// Check whether a specialization is well-formed in the current
7762 /// This routine determines whether a template specialization can be declared
7763 /// in the current context (C++ [temp.expl.spec]p2).
7765 /// \param S the semantic analysis object for which this check is being
7768 /// \param Specialized the entity being specialized or instantiated, which
7769 /// may be a kind of template (class template, function template, etc.) or
7770 /// a member of a class template (member function, static data member,
7773 /// \param PrevDecl the previous declaration of this entity, if any.
7775 /// \param Loc the location of the explicit specialization or instantiation of
7778 /// \param IsPartialSpecialization whether this is a partial specialization of
7779 /// a class template.
7781 /// \returns true if there was an error that we cannot recover from, false
7783 static bool CheckTemplateSpecializationScope(Sema &S,
7784 NamedDecl *Specialized,
7785 NamedDecl *PrevDecl,
7787 bool IsPartialSpecialization) {
7788 // Keep these "kind" numbers in sync with the %select statements in the
7789 // various diagnostics emitted by this routine.
7791 if (isa<ClassTemplateDecl>(Specialized))
7792 EntityKind = IsPartialSpecialization? 1 : 0;
7793 else if (isa<VarTemplateDecl>(Specialized))
7794 EntityKind = IsPartialSpecialization ? 3 : 2;
7795 else if (isa<FunctionTemplateDecl>(Specialized))
7797 else if (isa<CXXMethodDecl>(Specialized))
7799 else if (isa<VarDecl>(Specialized))
7801 else if (isa<RecordDecl>(Specialized))
7803 else if (isa<EnumDecl>(Specialized) && S.getLangOpts().CPlusPlus11)
7806 S.Diag(Loc, diag::err_template_spec_unknown_kind)
7807 << S.getLangOpts().CPlusPlus11;
7808 S.Diag(Specialized->getLocation(), diag::note_specialized_entity);
7812 // C++ [temp.expl.spec]p2:
7813 // An explicit specialization may be declared in any scope in which
7814 // the corresponding primary template may be defined.
7815 if (S.CurContext->getRedeclContext()->isFunctionOrMethod()) {
7816 S.Diag(Loc, diag::err_template_spec_decl_function_scope)
7821 // C++ [temp.class.spec]p6:
7822 // A class template partial specialization may be declared in any
7823 // scope in which the primary template may be defined.
7824 DeclContext *SpecializedContext =
7825 Specialized->getDeclContext()->getRedeclContext();
7826 DeclContext *DC = S.CurContext->getRedeclContext();
7828 // Make sure that this redeclaration (or definition) occurs in the same
7829 // scope or an enclosing namespace.
7830 if (!(DC->isFileContext() ? DC->Encloses(SpecializedContext)
7831 : DC->Equals(SpecializedContext))) {
7832 if (isa<TranslationUnitDecl>(SpecializedContext))
7833 S.Diag(Loc, diag::err_template_spec_redecl_global_scope)
7834 << EntityKind << Specialized;
7836 auto *ND = cast<NamedDecl>(SpecializedContext);
7837 int Diag = diag::err_template_spec_redecl_out_of_scope;
7838 if (S.getLangOpts().MicrosoftExt && !DC->isRecord())
7839 Diag = diag::ext_ms_template_spec_redecl_out_of_scope;
7840 S.Diag(Loc, Diag) << EntityKind << Specialized
7841 << ND << isa<CXXRecordDecl>(ND);
7844 S.Diag(Specialized->getLocation(), diag::note_specialized_entity);
7846 // Don't allow specializing in the wrong class during error recovery.
7847 // Otherwise, things can go horribly wrong.
7855 static SourceRange findTemplateParameterInType(unsigned Depth, Expr *E) {
7856 if (!E->isTypeDependent())
7857 return SourceLocation();
7858 DependencyChecker Checker(Depth, /*IgnoreNonTypeDependent*/true);
7859 Checker.TraverseStmt(E);
7860 if (Checker.MatchLoc.isInvalid())
7861 return E->getSourceRange();
7862 return Checker.MatchLoc;
7865 static SourceRange findTemplateParameter(unsigned Depth, TypeLoc TL) {
7866 if (!TL.getType()->isDependentType())
7867 return SourceLocation();
7868 DependencyChecker Checker(Depth, /*IgnoreNonTypeDependent*/true);
7869 Checker.TraverseTypeLoc(TL);
7870 if (Checker.MatchLoc.isInvalid())
7871 return TL.getSourceRange();
7872 return Checker.MatchLoc;
7875 /// Subroutine of Sema::CheckTemplatePartialSpecializationArgs
7876 /// that checks non-type template partial specialization arguments.
7877 static bool CheckNonTypeTemplatePartialSpecializationArgs(
7878 Sema &S, SourceLocation TemplateNameLoc, NonTypeTemplateParmDecl *Param,
7879 const TemplateArgument *Args, unsigned NumArgs, bool IsDefaultArgument) {
7880 for (unsigned I = 0; I != NumArgs; ++I) {
7881 if (Args[I].getKind() == TemplateArgument::Pack) {
7882 if (CheckNonTypeTemplatePartialSpecializationArgs(
7883 S, TemplateNameLoc, Param, Args[I].pack_begin(),
7884 Args[I].pack_size(), IsDefaultArgument))
7890 if (Args[I].getKind() != TemplateArgument::Expression)
7893 Expr *ArgExpr = Args[I].getAsExpr();
7895 // We can have a pack expansion of any of the bullets below.
7896 if (PackExpansionExpr *Expansion = dyn_cast<PackExpansionExpr>(ArgExpr))
7897 ArgExpr = Expansion->getPattern();
7899 // Strip off any implicit casts we added as part of type checking.
7900 while (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(ArgExpr))
7901 ArgExpr = ICE->getSubExpr();
7903 // C++ [temp.class.spec]p8:
7904 // A non-type argument is non-specialized if it is the name of a
7905 // non-type parameter. All other non-type arguments are
7908 // Below, we check the two conditions that only apply to
7909 // specialized non-type arguments, so skip any non-specialized
7911 if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(ArgExpr))
7912 if (isa<NonTypeTemplateParmDecl>(DRE->getDecl()))
7915 // C++ [temp.class.spec]p9:
7916 // Within the argument list of a class template partial
7917 // specialization, the following restrictions apply:
7918 // -- A partially specialized non-type argument expression
7919 // shall not involve a template parameter of the partial
7920 // specialization except when the argument expression is a
7921 // simple identifier.
7922 // -- The type of a template parameter corresponding to a
7923 // specialized non-type argument shall not be dependent on a
7924 // parameter of the specialization.
7925 // DR1315 removes the first bullet, leaving an incoherent set of rules.
7926 // We implement a compromise between the original rules and DR1315:
7927 // -- A specialized non-type template argument shall not be
7928 // type-dependent and the corresponding template parameter
7929 // shall have a non-dependent type.
7930 SourceRange ParamUseRange =
7931 findTemplateParameterInType(Param->getDepth(), ArgExpr);
7932 if (ParamUseRange.isValid()) {
7933 if (IsDefaultArgument) {
7934 S.Diag(TemplateNameLoc,
7935 diag::err_dependent_non_type_arg_in_partial_spec);
7936 S.Diag(ParamUseRange.getBegin(),
7937 diag::note_dependent_non_type_default_arg_in_partial_spec)
7940 S.Diag(ParamUseRange.getBegin(),
7941 diag::err_dependent_non_type_arg_in_partial_spec)
7947 ParamUseRange = findTemplateParameter(
7948 Param->getDepth(), Param->getTypeSourceInfo()->getTypeLoc());
7949 if (ParamUseRange.isValid()) {
7950 S.Diag(IsDefaultArgument ? TemplateNameLoc : ArgExpr->getBeginLoc(),
7951 diag::err_dependent_typed_non_type_arg_in_partial_spec)
7952 << Param->getType();
7953 S.Diag(Param->getLocation(), diag::note_template_param_here)
7954 << (IsDefaultArgument ? ParamUseRange : SourceRange())
7963 /// Check the non-type template arguments of a class template
7964 /// partial specialization according to C++ [temp.class.spec]p9.
7966 /// \param TemplateNameLoc the location of the template name.
7967 /// \param PrimaryTemplate the template parameters of the primary class
7969 /// \param NumExplicit the number of explicitly-specified template arguments.
7970 /// \param TemplateArgs the template arguments of the class template
7971 /// partial specialization.
7973 /// \returns \c true if there was an error, \c false otherwise.
7974 bool Sema::CheckTemplatePartialSpecializationArgs(
7975 SourceLocation TemplateNameLoc, TemplateDecl *PrimaryTemplate,
7976 unsigned NumExplicit, ArrayRef<TemplateArgument> TemplateArgs) {
7977 // We have to be conservative when checking a template in a dependent
7979 if (PrimaryTemplate->getDeclContext()->isDependentContext())
7982 TemplateParameterList *TemplateParams =
7983 PrimaryTemplate->getTemplateParameters();
7984 for (unsigned I = 0, N = TemplateParams->size(); I != N; ++I) {
7985 NonTypeTemplateParmDecl *Param
7986 = dyn_cast<NonTypeTemplateParmDecl>(TemplateParams->getParam(I));
7990 if (CheckNonTypeTemplatePartialSpecializationArgs(*this, TemplateNameLoc,
7991 Param, &TemplateArgs[I],
7992 1, I >= NumExplicit))
7999 DeclResult Sema::ActOnClassTemplateSpecialization(
8000 Scope *S, unsigned TagSpec, TagUseKind TUK, SourceLocation KWLoc,
8001 SourceLocation ModulePrivateLoc, CXXScopeSpec &SS,
8002 TemplateIdAnnotation &TemplateId, const ParsedAttributesView &Attr,
8003 MultiTemplateParamsArg TemplateParameterLists, SkipBodyInfo *SkipBody) {
8004 assert(TUK != TUK_Reference && "References are not specializations");
8006 // NOTE: KWLoc is the location of the tag keyword. This will instead
8007 // store the location of the outermost template keyword in the declaration.
8008 SourceLocation TemplateKWLoc = TemplateParameterLists.size() > 0
8009 ? TemplateParameterLists[0]->getTemplateLoc() : KWLoc;
8010 SourceLocation TemplateNameLoc = TemplateId.TemplateNameLoc;
8011 SourceLocation LAngleLoc = TemplateId.LAngleLoc;
8012 SourceLocation RAngleLoc = TemplateId.RAngleLoc;
8014 // Find the class template we're specializing
8015 TemplateName Name = TemplateId.Template.get();
8016 ClassTemplateDecl *ClassTemplate
8017 = dyn_cast_or_null<ClassTemplateDecl>(Name.getAsTemplateDecl());
8019 if (!ClassTemplate) {
8020 Diag(TemplateNameLoc, diag::err_not_class_template_specialization)
8021 << (Name.getAsTemplateDecl() &&
8022 isa<TemplateTemplateParmDecl>(Name.getAsTemplateDecl()));
8026 bool isMemberSpecialization = false;
8027 bool isPartialSpecialization = false;
8029 // Check the validity of the template headers that introduce this
8031 // FIXME: We probably shouldn't complain about these headers for
8032 // friend declarations.
8033 bool Invalid = false;
8034 TemplateParameterList *TemplateParams =
8035 MatchTemplateParametersToScopeSpecifier(
8036 KWLoc, TemplateNameLoc, SS, &TemplateId,
8037 TemplateParameterLists, TUK == TUK_Friend, isMemberSpecialization,
8042 if (TemplateParams && TemplateParams->size() > 0) {
8043 isPartialSpecialization = true;
8045 if (TUK == TUK_Friend) {
8046 Diag(KWLoc, diag::err_partial_specialization_friend)
8047 << SourceRange(LAngleLoc, RAngleLoc);
8051 // C++ [temp.class.spec]p10:
8052 // The template parameter list of a specialization shall not
8053 // contain default template argument values.
8054 for (unsigned I = 0, N = TemplateParams->size(); I != N; ++I) {
8055 Decl *Param = TemplateParams->getParam(I);
8056 if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(Param)) {
8057 if (TTP->hasDefaultArgument()) {
8058 Diag(TTP->getDefaultArgumentLoc(),
8059 diag::err_default_arg_in_partial_spec);
8060 TTP->removeDefaultArgument();
8062 } else if (NonTypeTemplateParmDecl *NTTP
8063 = dyn_cast<NonTypeTemplateParmDecl>(Param)) {
8064 if (Expr *DefArg = NTTP->getDefaultArgument()) {
8065 Diag(NTTP->getDefaultArgumentLoc(),
8066 diag::err_default_arg_in_partial_spec)
8067 << DefArg->getSourceRange();
8068 NTTP->removeDefaultArgument();
8071 TemplateTemplateParmDecl *TTP = cast<TemplateTemplateParmDecl>(Param);
8072 if (TTP->hasDefaultArgument()) {
8073 Diag(TTP->getDefaultArgument().getLocation(),
8074 diag::err_default_arg_in_partial_spec)
8075 << TTP->getDefaultArgument().getSourceRange();
8076 TTP->removeDefaultArgument();
8080 } else if (TemplateParams) {
8081 if (TUK == TUK_Friend)
8082 Diag(KWLoc, diag::err_template_spec_friend)
8083 << FixItHint::CreateRemoval(
8084 SourceRange(TemplateParams->getTemplateLoc(),
8085 TemplateParams->getRAngleLoc()))
8086 << SourceRange(LAngleLoc, RAngleLoc);
8088 assert(TUK == TUK_Friend && "should have a 'template<>' for this decl");
8091 // Check that the specialization uses the same tag kind as the
8092 // original template.
8093 TagTypeKind Kind = TypeWithKeyword::getTagTypeKindForTypeSpec(TagSpec);
8094 assert(Kind != TTK_Enum && "Invalid enum tag in class template spec!");
8095 if (!isAcceptableTagRedeclaration(ClassTemplate->getTemplatedDecl(),
8096 Kind, TUK == TUK_Definition, KWLoc,
8097 ClassTemplate->getIdentifier())) {
8098 Diag(KWLoc, diag::err_use_with_wrong_tag)
8100 << FixItHint::CreateReplacement(KWLoc,
8101 ClassTemplate->getTemplatedDecl()->getKindName());
8102 Diag(ClassTemplate->getTemplatedDecl()->getLocation(),
8103 diag::note_previous_use);
8104 Kind = ClassTemplate->getTemplatedDecl()->getTagKind();
8107 // Translate the parser's template argument list in our AST format.
8108 TemplateArgumentListInfo TemplateArgs =
8109 makeTemplateArgumentListInfo(*this, TemplateId);
8111 // Check for unexpanded parameter packs in any of the template arguments.
8112 for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I)
8113 if (DiagnoseUnexpandedParameterPack(TemplateArgs[I],
8114 UPPC_PartialSpecialization))
8117 // Check that the template argument list is well-formed for this
8119 SmallVector<TemplateArgument, 4> Converted;
8120 if (CheckTemplateArgumentList(ClassTemplate, TemplateNameLoc,
8121 TemplateArgs, false, Converted,
8122 /*UpdateArgsWithConversion=*/true))
8125 // Find the class template (partial) specialization declaration that
8126 // corresponds to these arguments.
8127 if (isPartialSpecialization) {
8128 if (CheckTemplatePartialSpecializationArgs(TemplateNameLoc, ClassTemplate,
8129 TemplateArgs.size(), Converted))
8132 // FIXME: Move this to CheckTemplatePartialSpecializationArgs so we
8133 // also do it during instantiation.
8134 bool InstantiationDependent;
8135 if (!Name.isDependent() &&
8136 !TemplateSpecializationType::anyDependentTemplateArguments(
8137 TemplateArgs.arguments(), InstantiationDependent)) {
8138 Diag(TemplateNameLoc, diag::err_partial_spec_fully_specialized)
8139 << ClassTemplate->getDeclName();
8140 isPartialSpecialization = false;
8144 void *InsertPos = nullptr;
8145 ClassTemplateSpecializationDecl *PrevDecl = nullptr;
8147 if (isPartialSpecialization)
8148 PrevDecl = ClassTemplate->findPartialSpecialization(Converted,
8152 PrevDecl = ClassTemplate->findSpecialization(Converted, InsertPos);
8154 ClassTemplateSpecializationDecl *Specialization = nullptr;
8156 // Check whether we can declare a class template specialization in
8157 // the current scope.
8158 if (TUK != TUK_Friend &&
8159 CheckTemplateSpecializationScope(*this, ClassTemplate, PrevDecl,
8161 isPartialSpecialization))
8164 // The canonical type
8166 if (isPartialSpecialization) {
8167 // Build the canonical type that describes the converted template
8168 // arguments of the class template partial specialization.
8169 TemplateName CanonTemplate = Context.getCanonicalTemplateName(Name);
8170 CanonType = Context.getTemplateSpecializationType(CanonTemplate,
8173 if (Context.hasSameType(CanonType,
8174 ClassTemplate->getInjectedClassNameSpecialization()) &&
8175 (!Context.getLangOpts().CPlusPlus2a ||
8176 !TemplateParams->hasAssociatedConstraints())) {
8177 // C++ [temp.class.spec]p9b3:
8179 // -- The argument list of the specialization shall not be identical
8180 // to the implicit argument list of the primary template.
8182 // This rule has since been removed, because it's redundant given DR1495,
8183 // but we keep it because it produces better diagnostics and recovery.
8184 Diag(TemplateNameLoc, diag::err_partial_spec_args_match_primary_template)
8185 << /*class template*/0 << (TUK == TUK_Definition)
8186 << FixItHint::CreateRemoval(SourceRange(LAngleLoc, RAngleLoc));
8187 return CheckClassTemplate(S, TagSpec, TUK, KWLoc, SS,
8188 ClassTemplate->getIdentifier(),
8192 AS_none, /*ModulePrivateLoc=*/SourceLocation(),
8193 /*FriendLoc*/SourceLocation(),
8194 TemplateParameterLists.size() - 1,
8195 TemplateParameterLists.data());
8198 // Create a new class template partial specialization declaration node.
8199 ClassTemplatePartialSpecializationDecl *PrevPartial
8200 = cast_or_null<ClassTemplatePartialSpecializationDecl>(PrevDecl);
8201 ClassTemplatePartialSpecializationDecl *Partial
8202 = ClassTemplatePartialSpecializationDecl::Create(Context, Kind,
8203 ClassTemplate->getDeclContext(),
8204 KWLoc, TemplateNameLoc,
8211 SetNestedNameSpecifier(*this, Partial, SS);
8212 if (TemplateParameterLists.size() > 1 && SS.isSet()) {
8213 Partial->setTemplateParameterListsInfo(
8214 Context, TemplateParameterLists.drop_back(1));
8218 ClassTemplate->AddPartialSpecialization(Partial, InsertPos);
8219 Specialization = Partial;
8221 // If we are providing an explicit specialization of a member class
8222 // template specialization, make a note of that.
8223 if (PrevPartial && PrevPartial->getInstantiatedFromMember())
8224 PrevPartial->setMemberSpecialization();
8226 CheckTemplatePartialSpecialization(Partial);
8228 // Create a new class template specialization declaration node for
8229 // this explicit specialization or friend declaration.
8231 = ClassTemplateSpecializationDecl::Create(Context, Kind,
8232 ClassTemplate->getDeclContext(),
8233 KWLoc, TemplateNameLoc,
8237 SetNestedNameSpecifier(*this, Specialization, SS);
8238 if (TemplateParameterLists.size() > 0) {
8239 Specialization->setTemplateParameterListsInfo(Context,
8240 TemplateParameterLists);
8244 ClassTemplate->AddSpecialization(Specialization, InsertPos);
8246 if (CurContext->isDependentContext()) {
8247 TemplateName CanonTemplate = Context.getCanonicalTemplateName(Name);
8248 CanonType = Context.getTemplateSpecializationType(
8249 CanonTemplate, Converted);
8251 CanonType = Context.getTypeDeclType(Specialization);
8255 // C++ [temp.expl.spec]p6:
8256 // If a template, a member template or the member of a class template is
8257 // explicitly specialized then that specialization shall be declared
8258 // before the first use of that specialization that would cause an implicit
8259 // instantiation to take place, in every translation unit in which such a
8260 // use occurs; no diagnostic is required.
8261 if (PrevDecl && PrevDecl->getPointOfInstantiation().isValid()) {
8263 for (Decl *Prev = PrevDecl; Prev; Prev = Prev->getPreviousDecl()) {
8264 // Is there any previous explicit specialization declaration?
8265 if (getTemplateSpecializationKind(Prev) == TSK_ExplicitSpecialization) {
8272 SourceRange Range(TemplateNameLoc, RAngleLoc);
8273 Diag(TemplateNameLoc, diag::err_specialization_after_instantiation)
8274 << Context.getTypeDeclType(Specialization) << Range;
8276 Diag(PrevDecl->getPointOfInstantiation(),
8277 diag::note_instantiation_required_here)
8278 << (PrevDecl->getTemplateSpecializationKind()
8279 != TSK_ImplicitInstantiation);
8284 // If this is not a friend, note that this is an explicit specialization.
8285 if (TUK != TUK_Friend)
8286 Specialization->setSpecializationKind(TSK_ExplicitSpecialization);
8288 // Check that this isn't a redefinition of this specialization.
8289 if (TUK == TUK_Definition) {
8290 RecordDecl *Def = Specialization->getDefinition();
8291 NamedDecl *Hidden = nullptr;
8292 if (Def && SkipBody && !hasVisibleDefinition(Def, &Hidden)) {
8293 SkipBody->ShouldSkip = true;
8294 SkipBody->Previous = Def;
8295 makeMergedDefinitionVisible(Hidden);
8297 SourceRange Range(TemplateNameLoc, RAngleLoc);
8298 Diag(TemplateNameLoc, diag::err_redefinition) << Specialization << Range;
8299 Diag(Def->getLocation(), diag::note_previous_definition);
8300 Specialization->setInvalidDecl();
8305 ProcessDeclAttributeList(S, Specialization, Attr);
8307 // Add alignment attributes if necessary; these attributes are checked when
8308 // the ASTContext lays out the structure.
8309 if (TUK == TUK_Definition && (!SkipBody || !SkipBody->ShouldSkip)) {
8310 AddAlignmentAttributesForRecord(Specialization);
8311 AddMsStructLayoutForRecord(Specialization);
8314 if (ModulePrivateLoc.isValid())
8315 Diag(Specialization->getLocation(), diag::err_module_private_specialization)
8316 << (isPartialSpecialization? 1 : 0)
8317 << FixItHint::CreateRemoval(ModulePrivateLoc);
8319 // Build the fully-sugared type for this class template
8320 // specialization as the user wrote in the specialization
8321 // itself. This means that we'll pretty-print the type retrieved
8322 // from the specialization's declaration the way that the user
8323 // actually wrote the specialization, rather than formatting the
8324 // name based on the "canonical" representation used to store the
8325 // template arguments in the specialization.
8326 TypeSourceInfo *WrittenTy
8327 = Context.getTemplateSpecializationTypeInfo(Name, TemplateNameLoc,
8328 TemplateArgs, CanonType);
8329 if (TUK != TUK_Friend) {
8330 Specialization->setTypeAsWritten(WrittenTy);
8331 Specialization->setTemplateKeywordLoc(TemplateKWLoc);
8334 // C++ [temp.expl.spec]p9:
8335 // A template explicit specialization is in the scope of the
8336 // namespace in which the template was defined.
8338 // We actually implement this paragraph where we set the semantic
8339 // context (in the creation of the ClassTemplateSpecializationDecl),
8340 // but we also maintain the lexical context where the actual
8341 // definition occurs.
8342 Specialization->setLexicalDeclContext(CurContext);
8344 // We may be starting the definition of this specialization.
8345 if (TUK == TUK_Definition && (!SkipBody || !SkipBody->ShouldSkip))
8346 Specialization->startDefinition();
8348 if (TUK == TUK_Friend) {
8349 FriendDecl *Friend = FriendDecl::Create(Context, CurContext,
8353 Friend->setAccess(AS_public);
8354 CurContext->addDecl(Friend);
8356 // Add the specialization into its lexical context, so that it can
8357 // be seen when iterating through the list of declarations in that
8358 // context. However, specializations are not found by name lookup.
8359 CurContext->addDecl(Specialization);
8362 if (SkipBody && SkipBody->ShouldSkip)
8363 return SkipBody->Previous;
8365 return Specialization;
8368 Decl *Sema::ActOnTemplateDeclarator(Scope *S,
8369 MultiTemplateParamsArg TemplateParameterLists,
8371 Decl *NewDecl = HandleDeclarator(S, D, TemplateParameterLists);
8372 ActOnDocumentableDecl(NewDecl);
8376 Decl *Sema::ActOnConceptDefinition(Scope *S,
8377 MultiTemplateParamsArg TemplateParameterLists,
8378 IdentifierInfo *Name, SourceLocation NameLoc,
8379 Expr *ConstraintExpr) {
8380 DeclContext *DC = CurContext;
8382 if (!DC->getRedeclContext()->isFileContext()) {
8384 diag::err_concept_decls_may_only_appear_in_global_namespace_scope);
8388 if (TemplateParameterLists.size() > 1) {
8389 Diag(NameLoc, diag::err_concept_extra_headers);
8393 if (TemplateParameterLists.front()->size() == 0) {
8394 Diag(NameLoc, diag::err_concept_no_parameters);
8398 ConceptDecl *NewDecl = ConceptDecl::Create(Context, DC, NameLoc, Name,
8399 TemplateParameterLists.front(),
8402 if (NewDecl->hasAssociatedConstraints()) {
8403 // C++2a [temp.concept]p4:
8404 // A concept shall not have associated constraints.
8405 Diag(NameLoc, diag::err_concept_no_associated_constraints);
8406 NewDecl->setInvalidDecl();
8409 // Check for conflicting previous declaration.
8410 DeclarationNameInfo NameInfo(NewDecl->getDeclName(), NameLoc);
8411 LookupResult Previous(*this, NameInfo, LookupOrdinaryName,
8412 ForVisibleRedeclaration);
8413 LookupName(Previous, S);
8415 FilterLookupForScope(Previous, DC, S, /*ConsiderLinkage=*/false,
8416 /*AllowInlineNamespace*/false);
8417 if (!Previous.empty()) {
8418 auto *Old = Previous.getRepresentativeDecl();
8419 Diag(NameLoc, isa<ConceptDecl>(Old) ? diag::err_redefinition :
8420 diag::err_redefinition_different_kind) << NewDecl->getDeclName();
8421 Diag(Old->getLocation(), diag::note_previous_definition);
8424 ActOnDocumentableDecl(NewDecl);
8425 PushOnScopeChains(NewDecl, S);
8429 /// \brief Strips various properties off an implicit instantiation
8430 /// that has just been explicitly specialized.
8431 static void StripImplicitInstantiation(NamedDecl *D) {
8432 D->dropAttr<DLLImportAttr>();
8433 D->dropAttr<DLLExportAttr>();
8435 if (FunctionDecl *FD = dyn_cast<FunctionDecl>(D))
8436 FD->setInlineSpecified(false);
8439 /// Compute the diagnostic location for an explicit instantiation
8440 // declaration or definition.
8441 static SourceLocation DiagLocForExplicitInstantiation(
8442 NamedDecl* D, SourceLocation PointOfInstantiation) {
8443 // Explicit instantiations following a specialization have no effect and
8444 // hence no PointOfInstantiation. In that case, walk decl backwards
8445 // until a valid name loc is found.
8446 SourceLocation PrevDiagLoc = PointOfInstantiation;
8447 for (Decl *Prev = D; Prev && !PrevDiagLoc.isValid();
8448 Prev = Prev->getPreviousDecl()) {
8449 PrevDiagLoc = Prev->getLocation();
8451 assert(PrevDiagLoc.isValid() &&
8452 "Explicit instantiation without point of instantiation?");
8456 /// Diagnose cases where we have an explicit template specialization
8457 /// before/after an explicit template instantiation, producing diagnostics
8458 /// for those cases where they are required and determining whether the
8459 /// new specialization/instantiation will have any effect.
8461 /// \param NewLoc the location of the new explicit specialization or
8464 /// \param NewTSK the kind of the new explicit specialization or instantiation.
8466 /// \param PrevDecl the previous declaration of the entity.
8468 /// \param PrevTSK the kind of the old explicit specialization or instantiatin.
8470 /// \param PrevPointOfInstantiation if valid, indicates where the previus
8471 /// declaration was instantiated (either implicitly or explicitly).
8473 /// \param HasNoEffect will be set to true to indicate that the new
8474 /// specialization or instantiation has no effect and should be ignored.
8476 /// \returns true if there was an error that should prevent the introduction of
8477 /// the new declaration into the AST, false otherwise.
8479 Sema::CheckSpecializationInstantiationRedecl(SourceLocation NewLoc,
8480 TemplateSpecializationKind NewTSK,
8481 NamedDecl *PrevDecl,
8482 TemplateSpecializationKind PrevTSK,
8483 SourceLocation PrevPointOfInstantiation,
8484 bool &HasNoEffect) {
8485 HasNoEffect = false;
8488 case TSK_Undeclared:
8489 case TSK_ImplicitInstantiation:
8491 (PrevTSK == TSK_Undeclared || PrevTSK == TSK_ImplicitInstantiation) &&
8492 "previous declaration must be implicit!");
8495 case TSK_ExplicitSpecialization:
8497 case TSK_Undeclared:
8498 case TSK_ExplicitSpecialization:
8499 // Okay, we're just specializing something that is either already
8500 // explicitly specialized or has merely been mentioned without any
8504 case TSK_ImplicitInstantiation:
8505 if (PrevPointOfInstantiation.isInvalid()) {
8506 // The declaration itself has not actually been instantiated, so it is
8507 // still okay to specialize it.
8508 StripImplicitInstantiation(PrevDecl);
8514 case TSK_ExplicitInstantiationDeclaration:
8515 case TSK_ExplicitInstantiationDefinition:
8516 assert((PrevTSK == TSK_ImplicitInstantiation ||
8517 PrevPointOfInstantiation.isValid()) &&
8518 "Explicit instantiation without point of instantiation?");
8520 // C++ [temp.expl.spec]p6:
8521 // If a template, a member template or the member of a class template
8522 // is explicitly specialized then that specialization shall be declared
8523 // before the first use of that specialization that would cause an
8524 // implicit instantiation to take place, in every translation unit in
8525 // which such a use occurs; no diagnostic is required.
8526 for (Decl *Prev = PrevDecl; Prev; Prev = Prev->getPreviousDecl()) {
8527 // Is there any previous explicit specialization declaration?
8528 if (getTemplateSpecializationKind(Prev) == TSK_ExplicitSpecialization)
8532 Diag(NewLoc, diag::err_specialization_after_instantiation)
8534 Diag(PrevPointOfInstantiation, diag::note_instantiation_required_here)
8535 << (PrevTSK != TSK_ImplicitInstantiation);
8539 llvm_unreachable("The switch over PrevTSK must be exhaustive.");
8541 case TSK_ExplicitInstantiationDeclaration:
8543 case TSK_ExplicitInstantiationDeclaration:
8544 // This explicit instantiation declaration is redundant (that's okay).
8548 case TSK_Undeclared:
8549 case TSK_ImplicitInstantiation:
8550 // We're explicitly instantiating something that may have already been
8551 // implicitly instantiated; that's fine.
8554 case TSK_ExplicitSpecialization:
8555 // C++0x [temp.explicit]p4:
8556 // For a given set of template parameters, if an explicit instantiation
8557 // of a template appears after a declaration of an explicit
8558 // specialization for that template, the explicit instantiation has no
8563 case TSK_ExplicitInstantiationDefinition:
8564 // C++0x [temp.explicit]p10:
8565 // If an entity is the subject of both an explicit instantiation
8566 // declaration and an explicit instantiation definition in the same
8567 // translation unit, the definition shall follow the declaration.
8569 diag::err_explicit_instantiation_declaration_after_definition);
8571 // Explicit instantiations following a specialization have no effect and
8572 // hence no PrevPointOfInstantiation. In that case, walk decl backwards
8573 // until a valid name loc is found.
8574 Diag(DiagLocForExplicitInstantiation(PrevDecl, PrevPointOfInstantiation),
8575 diag::note_explicit_instantiation_definition_here);
8579 llvm_unreachable("Unexpected TemplateSpecializationKind!");
8581 case TSK_ExplicitInstantiationDefinition:
8583 case TSK_Undeclared:
8584 case TSK_ImplicitInstantiation:
8585 // We're explicitly instantiating something that may have already been
8586 // implicitly instantiated; that's fine.
8589 case TSK_ExplicitSpecialization:
8590 // C++ DR 259, C++0x [temp.explicit]p4:
8591 // For a given set of template parameters, if an explicit
8592 // instantiation of a template appears after a declaration of
8593 // an explicit specialization for that template, the explicit
8594 // instantiation has no effect.
8595 Diag(NewLoc, diag::warn_explicit_instantiation_after_specialization)
8597 Diag(PrevDecl->getLocation(),
8598 diag::note_previous_template_specialization);
8602 case TSK_ExplicitInstantiationDeclaration:
8603 // We're explicitly instantiating a definition for something for which we
8604 // were previously asked to suppress instantiations. That's fine.
8606 // C++0x [temp.explicit]p4:
8607 // For a given set of template parameters, if an explicit instantiation
8608 // of a template appears after a declaration of an explicit
8609 // specialization for that template, the explicit instantiation has no
8611 for (Decl *Prev = PrevDecl; Prev; Prev = Prev->getPreviousDecl()) {
8612 // Is there any previous explicit specialization declaration?
8613 if (getTemplateSpecializationKind(Prev) == TSK_ExplicitSpecialization) {
8621 case TSK_ExplicitInstantiationDefinition:
8622 // C++0x [temp.spec]p5:
8623 // For a given template and a given set of template-arguments,
8624 // - an explicit instantiation definition shall appear at most once
8627 // MSVCCompat: MSVC silently ignores duplicate explicit instantiations.
8628 Diag(NewLoc, (getLangOpts().MSVCCompat)
8629 ? diag::ext_explicit_instantiation_duplicate
8630 : diag::err_explicit_instantiation_duplicate)
8632 Diag(DiagLocForExplicitInstantiation(PrevDecl, PrevPointOfInstantiation),
8633 diag::note_previous_explicit_instantiation);
8639 llvm_unreachable("Missing specialization/instantiation case?");
8642 /// Perform semantic analysis for the given dependent function
8643 /// template specialization.
8645 /// The only possible way to get a dependent function template specialization
8646 /// is with a friend declaration, like so:
8649 /// template \<class T> void foo(T);
8650 /// template \<class T> class A {
8651 /// friend void foo<>(T);
8655 /// There really isn't any useful analysis we can do here, so we
8656 /// just store the information.
8658 Sema::CheckDependentFunctionTemplateSpecialization(FunctionDecl *FD,
8659 const TemplateArgumentListInfo &ExplicitTemplateArgs,
8660 LookupResult &Previous) {
8661 // Remove anything from Previous that isn't a function template in
8662 // the correct context.
8663 DeclContext *FDLookupContext = FD->getDeclContext()->getRedeclContext();
8664 LookupResult::Filter F = Previous.makeFilter();
8665 enum DiscardReason { NotAFunctionTemplate, NotAMemberOfEnclosing };
8666 SmallVector<std::pair<DiscardReason, Decl *>, 8> DiscardedCandidates;
8667 while (F.hasNext()) {
8668 NamedDecl *D = F.next()->getUnderlyingDecl();
8669 if (!isa<FunctionTemplateDecl>(D)) {
8671 DiscardedCandidates.push_back(std::make_pair(NotAFunctionTemplate, D));
8675 if (!FDLookupContext->InEnclosingNamespaceSetOf(
8676 D->getDeclContext()->getRedeclContext())) {
8678 DiscardedCandidates.push_back(std::make_pair(NotAMemberOfEnclosing, D));
8684 if (Previous.empty()) {
8685 Diag(FD->getLocation(),
8686 diag::err_dependent_function_template_spec_no_match);
8687 for (auto &P : DiscardedCandidates)
8688 Diag(P.second->getLocation(),
8689 diag::note_dependent_function_template_spec_discard_reason)
8694 FD->setDependentTemplateSpecialization(Context, Previous.asUnresolvedSet(),
8695 ExplicitTemplateArgs);
8699 /// Perform semantic analysis for the given function template
8702 /// This routine performs all of the semantic analysis required for an
8703 /// explicit function template specialization. On successful completion,
8704 /// the function declaration \p FD will become a function template
8707 /// \param FD the function declaration, which will be updated to become a
8708 /// function template specialization.
8710 /// \param ExplicitTemplateArgs the explicitly-provided template arguments,
8711 /// if any. Note that this may be valid info even when 0 arguments are
8712 /// explicitly provided as in, e.g., \c void sort<>(char*, char*);
8713 /// as it anyway contains info on the angle brackets locations.
8715 /// \param Previous the set of declarations that may be specialized by
8716 /// this function specialization.
8718 /// \param QualifiedFriend whether this is a lookup for a qualified friend
8719 /// declaration with no explicit template argument list that might be
8720 /// befriending a function template specialization.
8721 bool Sema::CheckFunctionTemplateSpecialization(
8722 FunctionDecl *FD, TemplateArgumentListInfo *ExplicitTemplateArgs,
8723 LookupResult &Previous, bool QualifiedFriend) {
8724 // The set of function template specializations that could match this
8725 // explicit function template specialization.
8726 UnresolvedSet<8> Candidates;
8727 TemplateSpecCandidateSet FailedCandidates(FD->getLocation(),
8728 /*ForTakingAddress=*/false);
8730 llvm::SmallDenseMap<FunctionDecl *, TemplateArgumentListInfo, 8>
8731 ConvertedTemplateArgs;
8733 DeclContext *FDLookupContext = FD->getDeclContext()->getRedeclContext();
8734 for (LookupResult::iterator I = Previous.begin(), E = Previous.end();
8736 NamedDecl *Ovl = (*I)->getUnderlyingDecl();
8737 if (FunctionTemplateDecl *FunTmpl = dyn_cast<FunctionTemplateDecl>(Ovl)) {
8738 // Only consider templates found within the same semantic lookup scope as
8740 if (!FDLookupContext->InEnclosingNamespaceSetOf(
8741 Ovl->getDeclContext()->getRedeclContext()))
8744 // When matching a constexpr member function template specialization
8745 // against the primary template, we don't yet know whether the
8746 // specialization has an implicit 'const' (because we don't know whether
8747 // it will be a static member function until we know which template it
8748 // specializes), so adjust it now assuming it specializes this template.
8749 QualType FT = FD->getType();
8750 if (FD->isConstexpr()) {
8751 CXXMethodDecl *OldMD =
8752 dyn_cast<CXXMethodDecl>(FunTmpl->getTemplatedDecl());
8753 if (OldMD && OldMD->isConst()) {
8754 const FunctionProtoType *FPT = FT->castAs<FunctionProtoType>();
8755 FunctionProtoType::ExtProtoInfo EPI = FPT->getExtProtoInfo();
8756 EPI.TypeQuals.addConst();
8757 FT = Context.getFunctionType(FPT->getReturnType(),
8758 FPT->getParamTypes(), EPI);
8762 TemplateArgumentListInfo Args;
8763 if (ExplicitTemplateArgs)
8764 Args = *ExplicitTemplateArgs;
8766 // C++ [temp.expl.spec]p11:
8767 // A trailing template-argument can be left unspecified in the
8768 // template-id naming an explicit function template specialization
8769 // provided it can be deduced from the function argument type.
8770 // Perform template argument deduction to determine whether we may be
8771 // specializing this template.
8772 // FIXME: It is somewhat wasteful to build
8773 TemplateDeductionInfo Info(FailedCandidates.getLocation());
8774 FunctionDecl *Specialization = nullptr;
8775 if (TemplateDeductionResult TDK = DeduceTemplateArguments(
8776 cast<FunctionTemplateDecl>(FunTmpl->getFirstDecl()),
8777 ExplicitTemplateArgs ? &Args : nullptr, FT, Specialization,
8779 // Template argument deduction failed; record why it failed, so
8780 // that we can provide nifty diagnostics.
8781 FailedCandidates.addCandidate().set(
8782 I.getPair(), FunTmpl->getTemplatedDecl(),
8783 MakeDeductionFailureInfo(Context, TDK, Info));
8788 // Target attributes are part of the cuda function signature, so
8789 // the deduced template's cuda target must match that of the
8790 // specialization. Given that C++ template deduction does not
8791 // take target attributes into account, we reject candidates
8792 // here that have a different target.
8793 if (LangOpts.CUDA &&
8794 IdentifyCUDATarget(Specialization,
8795 /* IgnoreImplicitHDAttr = */ true) !=
8796 IdentifyCUDATarget(FD, /* IgnoreImplicitHDAttr = */ true)) {
8797 FailedCandidates.addCandidate().set(
8798 I.getPair(), FunTmpl->getTemplatedDecl(),
8799 MakeDeductionFailureInfo(Context, TDK_CUDATargetMismatch, Info));
8803 // Record this candidate.
8804 if (ExplicitTemplateArgs)
8805 ConvertedTemplateArgs[Specialization] = std::move(Args);
8806 Candidates.addDecl(Specialization, I.getAccess());
8810 // For a qualified friend declaration (with no explicit marker to indicate
8811 // that a template specialization was intended), note all (template and
8812 // non-template) candidates.
8813 if (QualifiedFriend && Candidates.empty()) {
8814 Diag(FD->getLocation(), diag::err_qualified_friend_no_match)
8815 << FD->getDeclName() << FDLookupContext;
8816 // FIXME: We should form a single candidate list and diagnose all
8817 // candidates at once, to get proper sorting and limiting.
8818 for (auto *OldND : Previous) {
8819 if (auto *OldFD = dyn_cast<FunctionDecl>(OldND->getUnderlyingDecl()))
8820 NoteOverloadCandidate(OldND, OldFD, CRK_None, FD->getType(), false);
8822 FailedCandidates.NoteCandidates(*this, FD->getLocation());
8826 // Find the most specialized function template.
8827 UnresolvedSetIterator Result = getMostSpecialized(
8828 Candidates.begin(), Candidates.end(), FailedCandidates, FD->getLocation(),
8829 PDiag(diag::err_function_template_spec_no_match) << FD->getDeclName(),
8830 PDiag(diag::err_function_template_spec_ambiguous)
8831 << FD->getDeclName() << (ExplicitTemplateArgs != nullptr),
8832 PDiag(diag::note_function_template_spec_matched));
8834 if (Result == Candidates.end())
8837 // Ignore access information; it doesn't figure into redeclaration checking.
8838 FunctionDecl *Specialization = cast<FunctionDecl>(*Result);
8840 FunctionTemplateSpecializationInfo *SpecInfo
8841 = Specialization->getTemplateSpecializationInfo();
8842 assert(SpecInfo && "Function template specialization info missing?");
8844 // Note: do not overwrite location info if previous template
8845 // specialization kind was explicit.
8846 TemplateSpecializationKind TSK = SpecInfo->getTemplateSpecializationKind();
8847 if (TSK == TSK_Undeclared || TSK == TSK_ImplicitInstantiation) {
8848 Specialization->setLocation(FD->getLocation());
8849 Specialization->setLexicalDeclContext(FD->getLexicalDeclContext());
8850 // C++11 [dcl.constexpr]p1: An explicit specialization of a constexpr
8851 // function can differ from the template declaration with respect to
8852 // the constexpr specifier.
8853 // FIXME: We need an update record for this AST mutation.
8854 // FIXME: What if there are multiple such prior declarations (for instance,
8855 // from different modules)?
8856 Specialization->setConstexprKind(FD->getConstexprKind());
8859 // FIXME: Check if the prior specialization has a point of instantiation.
8860 // If so, we have run afoul of .
8862 // If this is a friend declaration, then we're not really declaring
8863 // an explicit specialization.
8864 bool isFriend = (FD->getFriendObjectKind() != Decl::FOK_None);
8866 // Check the scope of this explicit specialization.
8868 CheckTemplateSpecializationScope(*this,
8869 Specialization->getPrimaryTemplate(),
8870 Specialization, FD->getLocation(),
8874 // C++ [temp.expl.spec]p6:
8875 // If a template, a member template or the member of a class template is
8876 // explicitly specialized then that specialization shall be declared
8877 // before the first use of that specialization that would cause an implicit
8878 // instantiation to take place, in every translation unit in which such a
8879 // use occurs; no diagnostic is required.
8880 bool HasNoEffect = false;
8882 CheckSpecializationInstantiationRedecl(FD->getLocation(),
8883 TSK_ExplicitSpecialization,
8885 SpecInfo->getTemplateSpecializationKind(),
8886 SpecInfo->getPointOfInstantiation(),
8890 // Mark the prior declaration as an explicit specialization, so that later
8891 // clients know that this is an explicit specialization.
8893 // Since explicit specializations do not inherit '=delete' from their
8894 // primary function template - check if the 'specialization' that was
8895 // implicitly generated (during template argument deduction for partial
8896 // ordering) from the most specialized of all the function templates that
8897 // 'FD' could have been specializing, has a 'deleted' definition. If so,
8898 // first check that it was implicitly generated during template argument
8899 // deduction by making sure it wasn't referenced, and then reset the deleted
8900 // flag to not-deleted, so that we can inherit that information from 'FD'.
8901 if (Specialization->isDeleted() && !SpecInfo->isExplicitSpecialization() &&
8902 !Specialization->getCanonicalDecl()->isReferenced()) {
8903 // FIXME: This assert will not hold in the presence of modules.
8905 Specialization->getCanonicalDecl() == Specialization &&
8906 "This must be the only existing declaration of this specialization");
8907 // FIXME: We need an update record for this AST mutation.
8908 Specialization->setDeletedAsWritten(false);
8910 // FIXME: We need an update record for this AST mutation.
8911 SpecInfo->setTemplateSpecializationKind(TSK_ExplicitSpecialization);
8912 MarkUnusedFileScopedDecl(Specialization);
8915 // Turn the given function declaration into a function template
8916 // specialization, with the template arguments from the previous
8918 // Take copies of (semantic and syntactic) template argument lists.
8919 const TemplateArgumentList* TemplArgs = new (Context)
8920 TemplateArgumentList(Specialization->getTemplateSpecializationArgs());
8921 FD->setFunctionTemplateSpecialization(
8922 Specialization->getPrimaryTemplate(), TemplArgs, /*InsertPos=*/nullptr,
8923 SpecInfo->getTemplateSpecializationKind(),
8924 ExplicitTemplateArgs ? &ConvertedTemplateArgs[Specialization] : nullptr);
8926 // A function template specialization inherits the target attributes
8927 // of its template. (We require the attributes explicitly in the
8928 // code to match, but a template may have implicit attributes by
8929 // virtue e.g. of being constexpr, and it passes these implicit
8930 // attributes on to its specializations.)
8932 inheritCUDATargetAttrs(FD, *Specialization->getPrimaryTemplate());
8934 // The "previous declaration" for this function template specialization is
8935 // the prior function template specialization.
8937 Previous.addDecl(Specialization);
8941 /// Perform semantic analysis for the given non-template member
8944 /// This routine performs all of the semantic analysis required for an
8945 /// explicit member function specialization. On successful completion,
8946 /// the function declaration \p FD will become a member function
8949 /// \param Member the member declaration, which will be updated to become a
8952 /// \param Previous the set of declarations, one of which may be specialized
8953 /// by this function specialization; the set will be modified to contain the
8954 /// redeclared member.
8956 Sema::CheckMemberSpecialization(NamedDecl *Member, LookupResult &Previous) {
8957 assert(!isa<TemplateDecl>(Member) && "Only for non-template members");
8959 // Try to find the member we are instantiating.
8960 NamedDecl *FoundInstantiation = nullptr;
8961 NamedDecl *Instantiation = nullptr;
8962 NamedDecl *InstantiatedFrom = nullptr;
8963 MemberSpecializationInfo *MSInfo = nullptr;
8965 if (Previous.empty()) {
8966 // Nowhere to look anyway.
8967 } else if (FunctionDecl *Function = dyn_cast<FunctionDecl>(Member)) {
8968 for (LookupResult::iterator I = Previous.begin(), E = Previous.end();
8970 NamedDecl *D = (*I)->getUnderlyingDecl();
8971 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(D)) {
8972 QualType Adjusted = Function->getType();
8973 if (!hasExplicitCallingConv(Adjusted))
8974 Adjusted = adjustCCAndNoReturn(Adjusted, Method->getType());
8975 // This doesn't handle deduced return types, but both function
8976 // declarations should be undeduced at this point.
8977 if (Context.hasSameType(Adjusted, Method->getType())) {
8978 FoundInstantiation = *I;
8979 Instantiation = Method;
8980 InstantiatedFrom = Method->getInstantiatedFromMemberFunction();
8981 MSInfo = Method->getMemberSpecializationInfo();
8986 } else if (isa<VarDecl>(Member)) {
8988 if (Previous.isSingleResult() &&
8989 (PrevVar = dyn_cast<VarDecl>(Previous.getFoundDecl())))
8990 if (PrevVar->isStaticDataMember()) {
8991 FoundInstantiation = Previous.getRepresentativeDecl();
8992 Instantiation = PrevVar;
8993 InstantiatedFrom = PrevVar->getInstantiatedFromStaticDataMember();
8994 MSInfo = PrevVar->getMemberSpecializationInfo();
8996 } else if (isa<RecordDecl>(Member)) {
8997 CXXRecordDecl *PrevRecord;
8998 if (Previous.isSingleResult() &&
8999 (PrevRecord = dyn_cast<CXXRecordDecl>(Previous.getFoundDecl()))) {
9000 FoundInstantiation = Previous.getRepresentativeDecl();
9001 Instantiation = PrevRecord;
9002 InstantiatedFrom = PrevRecord->getInstantiatedFromMemberClass();
9003 MSInfo = PrevRecord->getMemberSpecializationInfo();
9005 } else if (isa<EnumDecl>(Member)) {
9007 if (Previous.isSingleResult() &&
9008 (PrevEnum = dyn_cast<EnumDecl>(Previous.getFoundDecl()))) {
9009 FoundInstantiation = Previous.getRepresentativeDecl();
9010 Instantiation = PrevEnum;
9011 InstantiatedFrom = PrevEnum->getInstantiatedFromMemberEnum();
9012 MSInfo = PrevEnum->getMemberSpecializationInfo();
9016 if (!Instantiation) {
9017 // There is no previous declaration that matches. Since member
9018 // specializations are always out-of-line, the caller will complain about
9019 // this mismatch later.
9023 // A member specialization in a friend declaration isn't really declaring
9024 // an explicit specialization, just identifying a specific (possibly implicit)
9025 // specialization. Don't change the template specialization kind.
9027 // FIXME: Is this really valid? Other compilers reject.
9028 if (Member->getFriendObjectKind() != Decl::FOK_None) {
9029 // Preserve instantiation information.
9030 if (InstantiatedFrom && isa<CXXMethodDecl>(Member)) {
9031 cast<CXXMethodDecl>(Member)->setInstantiationOfMemberFunction(
9032 cast<CXXMethodDecl>(InstantiatedFrom),
9033 cast<CXXMethodDecl>(Instantiation)->getTemplateSpecializationKind());
9034 } else if (InstantiatedFrom && isa<CXXRecordDecl>(Member)) {
9035 cast<CXXRecordDecl>(Member)->setInstantiationOfMemberClass(
9036 cast<CXXRecordDecl>(InstantiatedFrom),
9037 cast<CXXRecordDecl>(Instantiation)->getTemplateSpecializationKind());
9041 Previous.addDecl(FoundInstantiation);
9045 // Make sure that this is a specialization of a member.
9046 if (!InstantiatedFrom) {
9047 Diag(Member->getLocation(), diag::err_spec_member_not_instantiated)
9049 Diag(Instantiation->getLocation(), diag::note_specialized_decl);
9053 // C++ [temp.expl.spec]p6:
9054 // If a template, a member template or the member of a class template is
9055 // explicitly specialized then that specialization shall be declared
9056 // before the first use of that specialization that would cause an implicit
9057 // instantiation to take place, in every translation unit in which such a
9058 // use occurs; no diagnostic is required.
9059 assert(MSInfo && "Member specialization info missing?");
9061 bool HasNoEffect = false;
9062 if (CheckSpecializationInstantiationRedecl(Member->getLocation(),
9063 TSK_ExplicitSpecialization,
9065 MSInfo->getTemplateSpecializationKind(),
9066 MSInfo->getPointOfInstantiation(),
9070 // Check the scope of this explicit specialization.
9071 if (CheckTemplateSpecializationScope(*this,
9073 Instantiation, Member->getLocation(),
9077 // Note that this member specialization is an "instantiation of" the
9078 // corresponding member of the original template.
9079 if (auto *MemberFunction = dyn_cast<FunctionDecl>(Member)) {
9080 FunctionDecl *InstantiationFunction = cast<FunctionDecl>(Instantiation);
9081 if (InstantiationFunction->getTemplateSpecializationKind() ==
9082 TSK_ImplicitInstantiation) {
9083 // Explicit specializations of member functions of class templates do not
9084 // inherit '=delete' from the member function they are specializing.
9085 if (InstantiationFunction->isDeleted()) {
9086 // FIXME: This assert will not hold in the presence of modules.
9087 assert(InstantiationFunction->getCanonicalDecl() ==
9088 InstantiationFunction);
9089 // FIXME: We need an update record for this AST mutation.
9090 InstantiationFunction->setDeletedAsWritten(false);
9094 MemberFunction->setInstantiationOfMemberFunction(
9095 cast<CXXMethodDecl>(InstantiatedFrom), TSK_ExplicitSpecialization);
9096 } else if (auto *MemberVar = dyn_cast<VarDecl>(Member)) {
9097 MemberVar->setInstantiationOfStaticDataMember(
9098 cast<VarDecl>(InstantiatedFrom), TSK_ExplicitSpecialization);
9099 } else if (auto *MemberClass = dyn_cast<CXXRecordDecl>(Member)) {
9100 MemberClass->setInstantiationOfMemberClass(
9101 cast<CXXRecordDecl>(InstantiatedFrom), TSK_ExplicitSpecialization);
9102 } else if (auto *MemberEnum = dyn_cast<EnumDecl>(Member)) {
9103 MemberEnum->setInstantiationOfMemberEnum(
9104 cast<EnumDecl>(InstantiatedFrom), TSK_ExplicitSpecialization);
9106 llvm_unreachable("unknown member specialization kind");
9109 // Save the caller the trouble of having to figure out which declaration
9110 // this specialization matches.
9112 Previous.addDecl(FoundInstantiation);
9116 /// Complete the explicit specialization of a member of a class template by
9117 /// updating the instantiated member to be marked as an explicit specialization.
9119 /// \param OrigD The member declaration instantiated from the template.
9120 /// \param Loc The location of the explicit specialization of the member.
9121 template<typename DeclT>
9122 static void completeMemberSpecializationImpl(Sema &S, DeclT *OrigD,
9123 SourceLocation Loc) {
9124 if (OrigD->getTemplateSpecializationKind() != TSK_ImplicitInstantiation)
9127 // FIXME: Inform AST mutation listeners of this AST mutation.
9128 // FIXME: If there are multiple in-class declarations of the member (from
9129 // multiple modules, or a declaration and later definition of a member type),
9130 // should we update all of them?
9131 OrigD->setTemplateSpecializationKind(TSK_ExplicitSpecialization);
9132 OrigD->setLocation(Loc);
9135 void Sema::CompleteMemberSpecialization(NamedDecl *Member,
9136 LookupResult &Previous) {
9137 NamedDecl *Instantiation = cast<NamedDecl>(Member->getCanonicalDecl());
9138 if (Instantiation == Member)
9141 if (auto *Function = dyn_cast<CXXMethodDecl>(Instantiation))
9142 completeMemberSpecializationImpl(*this, Function, Member->getLocation());
9143 else if (auto *Var = dyn_cast<VarDecl>(Instantiation))
9144 completeMemberSpecializationImpl(*this, Var, Member->getLocation());
9145 else if (auto *Record = dyn_cast<CXXRecordDecl>(Instantiation))
9146 completeMemberSpecializationImpl(*this, Record, Member->getLocation());
9147 else if (auto *Enum = dyn_cast<EnumDecl>(Instantiation))
9148 completeMemberSpecializationImpl(*this, Enum, Member->getLocation());
9150 llvm_unreachable("unknown member specialization kind");
9153 /// Check the scope of an explicit instantiation.
9155 /// \returns true if a serious error occurs, false otherwise.
9156 static bool CheckExplicitInstantiationScope(Sema &S, NamedDecl *D,
9157 SourceLocation InstLoc,
9158 bool WasQualifiedName) {
9159 DeclContext *OrigContext= D->getDeclContext()->getEnclosingNamespaceContext();
9160 DeclContext *CurContext = S.CurContext->getRedeclContext();
9162 if (CurContext->isRecord()) {
9163 S.Diag(InstLoc, diag::err_explicit_instantiation_in_class)
9168 // C++11 [temp.explicit]p3:
9169 // An explicit instantiation shall appear in an enclosing namespace of its
9170 // template. If the name declared in the explicit instantiation is an
9171 // unqualified name, the explicit instantiation shall appear in the
9172 // namespace where its template is declared or, if that namespace is inline
9173 // (7.3.1), any namespace from its enclosing namespace set.
9175 // This is DR275, which we do not retroactively apply to C++98/03.
9176 if (WasQualifiedName) {
9177 if (CurContext->Encloses(OrigContext))
9180 if (CurContext->InEnclosingNamespaceSetOf(OrigContext))
9184 if (NamespaceDecl *NS = dyn_cast<NamespaceDecl>(OrigContext)) {
9185 if (WasQualifiedName)
9187 S.getLangOpts().CPlusPlus11?
9188 diag::err_explicit_instantiation_out_of_scope :
9189 diag::warn_explicit_instantiation_out_of_scope_0x)
9193 S.getLangOpts().CPlusPlus11?
9194 diag::err_explicit_instantiation_unqualified_wrong_namespace :
9195 diag::warn_explicit_instantiation_unqualified_wrong_namespace_0x)
9199 S.getLangOpts().CPlusPlus11?
9200 diag::err_explicit_instantiation_must_be_global :
9201 diag::warn_explicit_instantiation_must_be_global_0x)
9203 S.Diag(D->getLocation(), diag::note_explicit_instantiation_here);
9207 /// Common checks for whether an explicit instantiation of \p D is valid.
9208 static bool CheckExplicitInstantiation(Sema &S, NamedDecl *D,
9209 SourceLocation InstLoc,
9210 bool WasQualifiedName,
9211 TemplateSpecializationKind TSK) {
9212 // C++ [temp.explicit]p13:
9213 // An explicit instantiation declaration shall not name a specialization of
9214 // a template with internal linkage.
9215 if (TSK == TSK_ExplicitInstantiationDeclaration &&
9216 D->getFormalLinkage() == InternalLinkage) {
9217 S.Diag(InstLoc, diag::err_explicit_instantiation_internal_linkage) << D;
9221 // C++11 [temp.explicit]p3: [DR 275]
9222 // An explicit instantiation shall appear in an enclosing namespace of its
9224 if (CheckExplicitInstantiationScope(S, D, InstLoc, WasQualifiedName))
9230 /// Determine whether the given scope specifier has a template-id in it.
9231 static bool ScopeSpecifierHasTemplateId(const CXXScopeSpec &SS) {
9235 // C++11 [temp.explicit]p3:
9236 // If the explicit instantiation is for a member function, a member class
9237 // or a static data member of a class template specialization, the name of
9238 // the class template specialization in the qualified-id for the member
9239 // name shall be a simple-template-id.
9241 // C++98 has the same restriction, just worded differently.
9242 for (NestedNameSpecifier *NNS = SS.getScopeRep(); NNS;
9243 NNS = NNS->getPrefix())
9244 if (const Type *T = NNS->getAsType())
9245 if (isa<TemplateSpecializationType>(T))
9251 /// Make a dllexport or dllimport attr on a class template specialization take
9253 static void dllExportImportClassTemplateSpecialization(
9254 Sema &S, ClassTemplateSpecializationDecl *Def) {
9255 auto *A = cast_or_null<InheritableAttr>(getDLLAttr(Def));
9256 assert(A && "dllExportImportClassTemplateSpecialization called "
9257 "on Def without dllexport or dllimport");
9259 // We reject explicit instantiations in class scope, so there should
9260 // never be any delayed exported classes to worry about.
9261 assert(S.DelayedDllExportClasses.empty() &&
9262 "delayed exports present at explicit instantiation");
9263 S.checkClassLevelDLLAttribute(Def);
9265 // Propagate attribute to base class templates.
9266 for (auto &B : Def->bases()) {
9267 if (auto *BT = dyn_cast_or_null<ClassTemplateSpecializationDecl>(
9268 B.getType()->getAsCXXRecordDecl()))
9269 S.propagateDLLAttrToBaseClassTemplate(Def, A, BT, B.getBeginLoc());
9272 S.referenceDLLExportedClassMethods();
9275 // Explicit instantiation of a class template specialization
9276 DeclResult Sema::ActOnExplicitInstantiation(
9277 Scope *S, SourceLocation ExternLoc, SourceLocation TemplateLoc,
9278 unsigned TagSpec, SourceLocation KWLoc, const CXXScopeSpec &SS,
9279 TemplateTy TemplateD, SourceLocation TemplateNameLoc,
9280 SourceLocation LAngleLoc, ASTTemplateArgsPtr TemplateArgsIn,
9281 SourceLocation RAngleLoc, const ParsedAttributesView &Attr) {
9282 // Find the class template we're specializing
9283 TemplateName Name = TemplateD.get();
9284 TemplateDecl *TD = Name.getAsTemplateDecl();
9285 // Check that the specialization uses the same tag kind as the
9286 // original template.
9287 TagTypeKind Kind = TypeWithKeyword::getTagTypeKindForTypeSpec(TagSpec);
9288 assert(Kind != TTK_Enum &&
9289 "Invalid enum tag in class template explicit instantiation!");
9291 ClassTemplateDecl *ClassTemplate = dyn_cast<ClassTemplateDecl>(TD);
9293 if (!ClassTemplate) {
9294 NonTagKind NTK = getNonTagTypeDeclKind(TD, Kind);
9295 Diag(TemplateNameLoc, diag::err_tag_reference_non_tag) << TD << NTK << Kind;
9296 Diag(TD->getLocation(), diag::note_previous_use);
9300 if (!isAcceptableTagRedeclaration(ClassTemplate->getTemplatedDecl(),
9301 Kind, /*isDefinition*/false, KWLoc,
9302 ClassTemplate->getIdentifier())) {
9303 Diag(KWLoc, diag::err_use_with_wrong_tag)
9305 << FixItHint::CreateReplacement(KWLoc,
9306 ClassTemplate->getTemplatedDecl()->getKindName());
9307 Diag(ClassTemplate->getTemplatedDecl()->getLocation(),
9308 diag::note_previous_use);
9309 Kind = ClassTemplate->getTemplatedDecl()->getTagKind();
9312 // C++0x [temp.explicit]p2:
9313 // There are two forms of explicit instantiation: an explicit instantiation
9314 // definition and an explicit instantiation declaration. An explicit
9315 // instantiation declaration begins with the extern keyword. [...]
9316 TemplateSpecializationKind TSK = ExternLoc.isInvalid()
9317 ? TSK_ExplicitInstantiationDefinition
9318 : TSK_ExplicitInstantiationDeclaration;
9320 if (TSK == TSK_ExplicitInstantiationDeclaration &&
9321 !Context.getTargetInfo().getTriple().isWindowsGNUEnvironment()) {
9322 // Check for dllexport class template instantiation declarations,
9323 // except for MinGW mode.
9324 for (const ParsedAttr &AL : Attr) {
9325 if (AL.getKind() == ParsedAttr::AT_DLLExport) {
9327 diag::warn_attribute_dllexport_explicit_instantiation_decl);
9328 Diag(AL.getLoc(), diag::note_attribute);
9333 if (auto *A = ClassTemplate->getTemplatedDecl()->getAttr<DLLExportAttr>()) {
9335 diag::warn_attribute_dllexport_explicit_instantiation_decl);
9336 Diag(A->getLocation(), diag::note_attribute);
9340 // In MSVC mode, dllimported explicit instantiation definitions are treated as
9341 // instantiation declarations for most purposes.
9342 bool DLLImportExplicitInstantiationDef = false;
9343 if (TSK == TSK_ExplicitInstantiationDefinition &&
9344 Context.getTargetInfo().getCXXABI().isMicrosoft()) {
9345 // Check for dllimport class template instantiation definitions.
9347 ClassTemplate->getTemplatedDecl()->getAttr<DLLImportAttr>();
9348 for (const ParsedAttr &AL : Attr) {
9349 if (AL.getKind() == ParsedAttr::AT_DLLImport)
9351 if (AL.getKind() == ParsedAttr::AT_DLLExport) {
9352 // dllexport trumps dllimport here.
9358 TSK = TSK_ExplicitInstantiationDeclaration;
9359 DLLImportExplicitInstantiationDef = true;
9363 // Translate the parser's template argument list in our AST format.
9364 TemplateArgumentListInfo TemplateArgs(LAngleLoc, RAngleLoc);
9365 translateTemplateArguments(TemplateArgsIn, TemplateArgs);
9367 // Check that the template argument list is well-formed for this
9369 SmallVector<TemplateArgument, 4> Converted;
9370 if (CheckTemplateArgumentList(ClassTemplate, TemplateNameLoc,
9371 TemplateArgs, false, Converted,
9372 /*UpdateArgsWithConversion=*/true))
9375 // Find the class template specialization declaration that
9376 // corresponds to these arguments.
9377 void *InsertPos = nullptr;
9378 ClassTemplateSpecializationDecl *PrevDecl
9379 = ClassTemplate->findSpecialization(Converted, InsertPos);
9381 TemplateSpecializationKind PrevDecl_TSK
9382 = PrevDecl ? PrevDecl->getTemplateSpecializationKind() : TSK_Undeclared;
9384 if (TSK == TSK_ExplicitInstantiationDefinition && PrevDecl != nullptr &&
9385 Context.getTargetInfo().getTriple().isWindowsGNUEnvironment()) {
9386 // Check for dllexport class template instantiation definitions in MinGW
9387 // mode, if a previous declaration of the instantiation was seen.
9388 for (const ParsedAttr &AL : Attr) {
9389 if (AL.getKind() == ParsedAttr::AT_DLLExport) {
9391 diag::warn_attribute_dllexport_explicit_instantiation_def);
9397 if (CheckExplicitInstantiation(*this, ClassTemplate, TemplateNameLoc,
9401 ClassTemplateSpecializationDecl *Specialization = nullptr;
9403 bool HasNoEffect = false;
9405 if (CheckSpecializationInstantiationRedecl(TemplateNameLoc, TSK,
9406 PrevDecl, PrevDecl_TSK,
9407 PrevDecl->getPointOfInstantiation(),
9411 // Even though HasNoEffect == true means that this explicit instantiation
9412 // has no effect on semantics, we go on to put its syntax in the AST.
9414 if (PrevDecl_TSK == TSK_ImplicitInstantiation ||
9415 PrevDecl_TSK == TSK_Undeclared) {
9416 // Since the only prior class template specialization with these
9417 // arguments was referenced but not declared, reuse that
9418 // declaration node as our own, updating the source location
9419 // for the template name to reflect our new declaration.
9420 // (Other source locations will be updated later.)
9421 Specialization = PrevDecl;
9422 Specialization->setLocation(TemplateNameLoc);
9426 if (PrevDecl_TSK == TSK_ExplicitInstantiationDeclaration &&
9427 DLLImportExplicitInstantiationDef) {
9428 // The new specialization might add a dllimport attribute.
9429 HasNoEffect = false;
9433 if (!Specialization) {
9434 // Create a new class template specialization declaration node for
9435 // this explicit specialization.
9437 = ClassTemplateSpecializationDecl::Create(Context, Kind,
9438 ClassTemplate->getDeclContext(),
9439 KWLoc, TemplateNameLoc,
9443 SetNestedNameSpecifier(*this, Specialization, SS);
9445 if (!HasNoEffect && !PrevDecl) {
9446 // Insert the new specialization.
9447 ClassTemplate->AddSpecialization(Specialization, InsertPos);
9451 // Build the fully-sugared type for this explicit instantiation as
9452 // the user wrote in the explicit instantiation itself. This means
9453 // that we'll pretty-print the type retrieved from the
9454 // specialization's declaration the way that the user actually wrote
9455 // the explicit instantiation, rather than formatting the name based
9456 // on the "canonical" representation used to store the template
9457 // arguments in the specialization.
9458 TypeSourceInfo *WrittenTy
9459 = Context.getTemplateSpecializationTypeInfo(Name, TemplateNameLoc,
9461 Context.getTypeDeclType(Specialization));
9462 Specialization->setTypeAsWritten(WrittenTy);
9464 // Set source locations for keywords.
9465 Specialization->setExternLoc(ExternLoc);
9466 Specialization->setTemplateKeywordLoc(TemplateLoc);
9467 Specialization->setBraceRange(SourceRange());
9469 bool PreviouslyDLLExported = Specialization->hasAttr<DLLExportAttr>();
9470 ProcessDeclAttributeList(S, Specialization, Attr);
9472 // Add the explicit instantiation into its lexical context. However,
9473 // since explicit instantiations are never found by name lookup, we
9474 // just put it into the declaration context directly.
9475 Specialization->setLexicalDeclContext(CurContext);
9476 CurContext->addDecl(Specialization);
9478 // Syntax is now OK, so return if it has no other effect on semantics.
9480 // Set the template specialization kind.
9481 Specialization->setTemplateSpecializationKind(TSK);
9482 return Specialization;
9485 // C++ [temp.explicit]p3:
9486 // A definition of a class template or class member template
9487 // shall be in scope at the point of the explicit instantiation of
9488 // the class template or class member template.
9490 // This check comes when we actually try to perform the
9492 ClassTemplateSpecializationDecl *Def
9493 = cast_or_null<ClassTemplateSpecializationDecl>(
9494 Specialization->getDefinition());
9496 InstantiateClassTemplateSpecialization(TemplateNameLoc, Specialization, TSK);
9497 else if (TSK == TSK_ExplicitInstantiationDefinition) {
9498 MarkVTableUsed(TemplateNameLoc, Specialization, true);
9499 Specialization->setPointOfInstantiation(Def->getPointOfInstantiation());
9502 // Instantiate the members of this class template specialization.
9503 Def = cast_or_null<ClassTemplateSpecializationDecl>(
9504 Specialization->getDefinition());
9506 TemplateSpecializationKind Old_TSK = Def->getTemplateSpecializationKind();
9507 // Fix a TSK_ExplicitInstantiationDeclaration followed by a
9508 // TSK_ExplicitInstantiationDefinition
9509 if (Old_TSK == TSK_ExplicitInstantiationDeclaration &&
9510 (TSK == TSK_ExplicitInstantiationDefinition ||
9511 DLLImportExplicitInstantiationDef)) {
9512 // FIXME: Need to notify the ASTMutationListener that we did this.
9513 Def->setTemplateSpecializationKind(TSK);
9515 if (!getDLLAttr(Def) && getDLLAttr(Specialization) &&
9516 (Context.getTargetInfo().getCXXABI().isMicrosoft() ||
9517 Context.getTargetInfo().getTriple().isWindowsItaniumEnvironment())) {
9518 // In the MS ABI, an explicit instantiation definition can add a dll
9519 // attribute to a template with a previous instantiation declaration.
9520 // MinGW doesn't allow this.
9521 auto *A = cast<InheritableAttr>(
9522 getDLLAttr(Specialization)->clone(getASTContext()));
9523 A->setInherited(true);
9525 dllExportImportClassTemplateSpecialization(*this, Def);
9529 // Fix a TSK_ImplicitInstantiation followed by a
9530 // TSK_ExplicitInstantiationDefinition
9531 bool NewlyDLLExported =
9532 !PreviouslyDLLExported && Specialization->hasAttr<DLLExportAttr>();
9533 if (Old_TSK == TSK_ImplicitInstantiation && NewlyDLLExported &&
9534 (Context.getTargetInfo().getCXXABI().isMicrosoft() ||
9535 Context.getTargetInfo().getTriple().isWindowsItaniumEnvironment())) {
9536 // In the MS ABI, an explicit instantiation definition can add a dll
9537 // attribute to a template with a previous implicit instantiation.
9538 // MinGW doesn't allow this. We limit clang to only adding dllexport, to
9539 // avoid potentially strange codegen behavior. For example, if we extend
9540 // this conditional to dllimport, and we have a source file calling a
9541 // method on an implicitly instantiated template class instance and then
9542 // declaring a dllimport explicit instantiation definition for the same
9543 // template class, the codegen for the method call will not respect the
9544 // dllimport, while it will with cl. The Def will already have the DLL
9545 // attribute, since the Def and Specialization will be the same in the
9546 // case of Old_TSK == TSK_ImplicitInstantiation, and we already added the
9547 // attribute to the Specialization; we just need to make it take effect.
9548 assert(Def == Specialization &&
9549 "Def and Specialization should match for implicit instantiation");
9550 dllExportImportClassTemplateSpecialization(*this, Def);
9553 // In MinGW mode, export the template instantiation if the declaration
9554 // was marked dllexport.
9555 if (PrevDecl_TSK == TSK_ExplicitInstantiationDeclaration &&
9556 Context.getTargetInfo().getTriple().isWindowsGNUEnvironment() &&
9557 PrevDecl->hasAttr<DLLExportAttr>()) {
9558 dllExportImportClassTemplateSpecialization(*this, Def);
9561 // Set the template specialization kind. Make sure it is set before
9562 // instantiating the members which will trigger ASTConsumer callbacks.
9563 Specialization->setTemplateSpecializationKind(TSK);
9564 InstantiateClassTemplateSpecializationMembers(TemplateNameLoc, Def, TSK);
9567 // Set the template specialization kind.
9568 Specialization->setTemplateSpecializationKind(TSK);
9571 return Specialization;
9574 // Explicit instantiation of a member class of a class template.
9576 Sema::ActOnExplicitInstantiation(Scope *S, SourceLocation ExternLoc,
9577 SourceLocation TemplateLoc, unsigned TagSpec,
9578 SourceLocation KWLoc, CXXScopeSpec &SS,
9579 IdentifierInfo *Name, SourceLocation NameLoc,
9580 const ParsedAttributesView &Attr) {
9583 bool IsDependent = false;
9584 Decl *TagD = ActOnTag(S, TagSpec, Sema::TUK_Reference,
9585 KWLoc, SS, Name, NameLoc, Attr, AS_none,
9586 /*ModulePrivateLoc=*/SourceLocation(),
9587 MultiTemplateParamsArg(), Owned, IsDependent,
9588 SourceLocation(), false, TypeResult(),
9589 /*IsTypeSpecifier*/false,
9590 /*IsTemplateParamOrArg*/false);
9591 assert(!IsDependent && "explicit instantiation of dependent name not yet handled");
9596 TagDecl *Tag = cast<TagDecl>(TagD);
9597 assert(!Tag->isEnum() && "shouldn't see enumerations here");
9599 if (Tag->isInvalidDecl())
9602 CXXRecordDecl *Record = cast<CXXRecordDecl>(Tag);
9603 CXXRecordDecl *Pattern = Record->getInstantiatedFromMemberClass();
9605 Diag(TemplateLoc, diag::err_explicit_instantiation_nontemplate_type)
9606 << Context.getTypeDeclType(Record);
9607 Diag(Record->getLocation(), diag::note_nontemplate_decl_here);
9611 // C++0x [temp.explicit]p2:
9612 // If the explicit instantiation is for a class or member class, the
9613 // elaborated-type-specifier in the declaration shall include a
9614 // simple-template-id.
9616 // C++98 has the same restriction, just worded differently.
9617 if (!ScopeSpecifierHasTemplateId(SS))
9618 Diag(TemplateLoc, diag::ext_explicit_instantiation_without_qualified_id)
9619 << Record << SS.getRange();
9621 // C++0x [temp.explicit]p2:
9622 // There are two forms of explicit instantiation: an explicit instantiation
9623 // definition and an explicit instantiation declaration. An explicit
9624 // instantiation declaration begins with the extern keyword. [...]
9625 TemplateSpecializationKind TSK
9626 = ExternLoc.isInvalid()? TSK_ExplicitInstantiationDefinition
9627 : TSK_ExplicitInstantiationDeclaration;
9629 CheckExplicitInstantiation(*this, Record, NameLoc, true, TSK);
9631 // Verify that it is okay to explicitly instantiate here.
9632 CXXRecordDecl *PrevDecl
9633 = cast_or_null<CXXRecordDecl>(Record->getPreviousDecl());
9634 if (!PrevDecl && Record->getDefinition())
9637 MemberSpecializationInfo *MSInfo = PrevDecl->getMemberSpecializationInfo();
9638 bool HasNoEffect = false;
9639 assert(MSInfo && "No member specialization information?");
9640 if (CheckSpecializationInstantiationRedecl(TemplateLoc, TSK,
9642 MSInfo->getTemplateSpecializationKind(),
9643 MSInfo->getPointOfInstantiation(),
9650 CXXRecordDecl *RecordDef
9651 = cast_or_null<CXXRecordDecl>(Record->getDefinition());
9653 // C++ [temp.explicit]p3:
9654 // A definition of a member class of a class template shall be in scope
9655 // at the point of an explicit instantiation of the member class.
9657 = cast_or_null<CXXRecordDecl>(Pattern->getDefinition());
9659 Diag(TemplateLoc, diag::err_explicit_instantiation_undefined_member)
9660 << 0 << Record->getDeclName() << Record->getDeclContext();
9661 Diag(Pattern->getLocation(), diag::note_forward_declaration)
9665 if (InstantiateClass(NameLoc, Record, Def,
9666 getTemplateInstantiationArgs(Record),
9670 RecordDef = cast_or_null<CXXRecordDecl>(Record->getDefinition());
9676 // Instantiate all of the members of the class.
9677 InstantiateClassMembers(NameLoc, RecordDef,
9678 getTemplateInstantiationArgs(Record), TSK);
9680 if (TSK == TSK_ExplicitInstantiationDefinition)
9681 MarkVTableUsed(NameLoc, RecordDef, true);
9683 // FIXME: We don't have any representation for explicit instantiations of
9684 // member classes. Such a representation is not needed for compilation, but it
9685 // should be available for clients that want to see all of the declarations in
9690 DeclResult Sema::ActOnExplicitInstantiation(Scope *S,
9691 SourceLocation ExternLoc,
9692 SourceLocation TemplateLoc,
9694 // Explicit instantiations always require a name.
9695 // TODO: check if/when DNInfo should replace Name.
9696 DeclarationNameInfo NameInfo = GetNameForDeclarator(D);
9697 DeclarationName Name = NameInfo.getName();
9699 if (!D.isInvalidType())
9700 Diag(D.getDeclSpec().getBeginLoc(),
9701 diag::err_explicit_instantiation_requires_name)
9702 << D.getDeclSpec().getSourceRange() << D.getSourceRange();
9707 // The scope passed in may not be a decl scope. Zip up the scope tree until
9708 // we find one that is.
9709 while ((S->getFlags() & Scope::DeclScope) == 0 ||
9710 (S->getFlags() & Scope::TemplateParamScope) != 0)
9713 // Determine the type of the declaration.
9714 TypeSourceInfo *T = GetTypeForDeclarator(D, S);
9715 QualType R = T->getType();
9720 // A storage-class-specifier shall not be specified in [...] an explicit
9721 // instantiation (14.7.2) directive.
9722 if (D.getDeclSpec().getStorageClassSpec() == DeclSpec::SCS_typedef) {
9723 Diag(D.getIdentifierLoc(), diag::err_explicit_instantiation_of_typedef)
9726 } else if (D.getDeclSpec().getStorageClassSpec()
9727 != DeclSpec::SCS_unspecified) {
9728 // Complain about then remove the storage class specifier.
9729 Diag(D.getIdentifierLoc(), diag::err_explicit_instantiation_storage_class)
9730 << FixItHint::CreateRemoval(D.getDeclSpec().getStorageClassSpecLoc());
9732 D.getMutableDeclSpec().ClearStorageClassSpecs();
9735 // C++0x [temp.explicit]p1:
9736 // [...] An explicit instantiation of a function template shall not use the
9737 // inline or constexpr specifiers.
9738 // Presumably, this also applies to member functions of class templates as
9740 if (D.getDeclSpec().isInlineSpecified())
9741 Diag(D.getDeclSpec().getInlineSpecLoc(),
9742 getLangOpts().CPlusPlus11 ?
9743 diag::err_explicit_instantiation_inline :
9744 diag::warn_explicit_instantiation_inline_0x)
9745 << FixItHint::CreateRemoval(D.getDeclSpec().getInlineSpecLoc());
9746 if (D.getDeclSpec().hasConstexprSpecifier() && R->isFunctionType())
9747 // FIXME: Add a fix-it to remove the 'constexpr' and add a 'const' if one is
9748 // not already specified.
9749 Diag(D.getDeclSpec().getConstexprSpecLoc(),
9750 diag::err_explicit_instantiation_constexpr);
9752 // A deduction guide is not on the list of entities that can be explicitly
9754 if (Name.getNameKind() == DeclarationName::CXXDeductionGuideName) {
9755 Diag(D.getDeclSpec().getBeginLoc(), diag::err_deduction_guide_specialized)
9756 << /*explicit instantiation*/ 0;
9760 // C++0x [temp.explicit]p2:
9761 // There are two forms of explicit instantiation: an explicit instantiation
9762 // definition and an explicit instantiation declaration. An explicit
9763 // instantiation declaration begins with the extern keyword. [...]
9764 TemplateSpecializationKind TSK
9765 = ExternLoc.isInvalid()? TSK_ExplicitInstantiationDefinition
9766 : TSK_ExplicitInstantiationDeclaration;
9768 LookupResult Previous(*this, NameInfo, LookupOrdinaryName);
9769 LookupParsedName(Previous, S, &D.getCXXScopeSpec());
9771 if (!R->isFunctionType()) {
9772 // C++ [temp.explicit]p1:
9773 // A [...] static data member of a class template can be explicitly
9774 // instantiated from the member definition associated with its class
9776 // C++1y [temp.explicit]p1:
9777 // A [...] variable [...] template specialization can be explicitly
9778 // instantiated from its template.
9779 if (Previous.isAmbiguous())
9782 VarDecl *Prev = Previous.getAsSingle<VarDecl>();
9783 VarTemplateDecl *PrevTemplate = Previous.getAsSingle<VarTemplateDecl>();
9785 if (!PrevTemplate) {
9786 if (!Prev || !Prev->isStaticDataMember()) {
9787 // We expect to see a static data member here.
9788 Diag(D.getIdentifierLoc(), diag::err_explicit_instantiation_not_known)
9790 for (LookupResult::iterator P = Previous.begin(), PEnd = Previous.end();
9792 Diag((*P)->getLocation(), diag::note_explicit_instantiation_here);
9796 if (!Prev->getInstantiatedFromStaticDataMember()) {
9797 // FIXME: Check for explicit specialization?
9798 Diag(D.getIdentifierLoc(),
9799 diag::err_explicit_instantiation_data_member_not_instantiated)
9801 Diag(Prev->getLocation(), diag::note_explicit_instantiation_here);
9802 // FIXME: Can we provide a note showing where this was declared?
9806 // Explicitly instantiate a variable template.
9808 // C++1y [dcl.spec.auto]p6:
9809 // ... A program that uses auto or decltype(auto) in a context not
9810 // explicitly allowed in this section is ill-formed.
9812 // This includes auto-typed variable template instantiations.
9813 if (R->isUndeducedType()) {
9814 Diag(T->getTypeLoc().getBeginLoc(),
9815 diag::err_auto_not_allowed_var_inst);
9819 if (D.getName().getKind() != UnqualifiedIdKind::IK_TemplateId) {
9820 // C++1y [temp.explicit]p3:
9821 // If the explicit instantiation is for a variable, the unqualified-id
9822 // in the declaration shall be a template-id.
9823 Diag(D.getIdentifierLoc(),
9824 diag::err_explicit_instantiation_without_template_id)
9826 Diag(PrevTemplate->getLocation(),
9827 diag::note_explicit_instantiation_here);
9831 // Translate the parser's template argument list into our AST format.
9832 TemplateArgumentListInfo TemplateArgs =
9833 makeTemplateArgumentListInfo(*this, *D.getName().TemplateId);
9835 DeclResult Res = CheckVarTemplateId(PrevTemplate, TemplateLoc,
9836 D.getIdentifierLoc(), TemplateArgs);
9837 if (Res.isInvalid())
9840 // Ignore access control bits, we don't need them for redeclaration
9842 Prev = cast<VarDecl>(Res.get());
9845 // C++0x [temp.explicit]p2:
9846 // If the explicit instantiation is for a member function, a member class
9847 // or a static data member of a class template specialization, the name of
9848 // the class template specialization in the qualified-id for the member
9849 // name shall be a simple-template-id.
9851 // C++98 has the same restriction, just worded differently.
9853 // This does not apply to variable template specializations, where the
9854 // template-id is in the unqualified-id instead.
9855 if (!ScopeSpecifierHasTemplateId(D.getCXXScopeSpec()) && !PrevTemplate)
9856 Diag(D.getIdentifierLoc(),
9857 diag::ext_explicit_instantiation_without_qualified_id)
9858 << Prev << D.getCXXScopeSpec().getRange();
9860 CheckExplicitInstantiation(*this, Prev, D.getIdentifierLoc(), true, TSK);
9862 // Verify that it is okay to explicitly instantiate here.
9863 TemplateSpecializationKind PrevTSK = Prev->getTemplateSpecializationKind();
9864 SourceLocation POI = Prev->getPointOfInstantiation();
9865 bool HasNoEffect = false;
9866 if (CheckSpecializationInstantiationRedecl(D.getIdentifierLoc(), TSK, Prev,
9867 PrevTSK, POI, HasNoEffect))
9871 // Instantiate static data member or variable template.
9872 Prev->setTemplateSpecializationKind(TSK, D.getIdentifierLoc());
9873 // Merge attributes.
9874 ProcessDeclAttributeList(S, Prev, D.getDeclSpec().getAttributes());
9875 if (TSK == TSK_ExplicitInstantiationDefinition)
9876 InstantiateVariableDefinition(D.getIdentifierLoc(), Prev);
9879 // Check the new variable specialization against the parsed input.
9880 if (PrevTemplate && Prev && !Context.hasSameType(Prev->getType(), R)) {
9881 Diag(T->getTypeLoc().getBeginLoc(),
9882 diag::err_invalid_var_template_spec_type)
9883 << 0 << PrevTemplate << R << Prev->getType();
9884 Diag(PrevTemplate->getLocation(), diag::note_template_declared_here)
9885 << 2 << PrevTemplate->getDeclName();
9889 // FIXME: Create an ExplicitInstantiation node?
9890 return (Decl*) nullptr;
9893 // If the declarator is a template-id, translate the parser's template
9894 // argument list into our AST format.
9895 bool HasExplicitTemplateArgs = false;
9896 TemplateArgumentListInfo TemplateArgs;
9897 if (D.getName().getKind() == UnqualifiedIdKind::IK_TemplateId) {
9898 TemplateArgs = makeTemplateArgumentListInfo(*this, *D.getName().TemplateId);
9899 HasExplicitTemplateArgs = true;
9902 // C++ [temp.explicit]p1:
9903 // A [...] function [...] can be explicitly instantiated from its template.
9904 // A member function [...] of a class template can be explicitly
9905 // instantiated from the member definition associated with its class
9907 UnresolvedSet<8> TemplateMatches;
9908 FunctionDecl *NonTemplateMatch = nullptr;
9909 TemplateSpecCandidateSet FailedCandidates(D.getIdentifierLoc());
9910 for (LookupResult::iterator P = Previous.begin(), PEnd = Previous.end();
9912 NamedDecl *Prev = *P;
9913 if (!HasExplicitTemplateArgs) {
9914 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Prev)) {
9915 QualType Adjusted = adjustCCAndNoReturn(R, Method->getType(),
9916 /*AdjustExceptionSpec*/true);
9917 if (Context.hasSameUnqualifiedType(Method->getType(), Adjusted)) {
9918 if (Method->getPrimaryTemplate()) {
9919 TemplateMatches.addDecl(Method, P.getAccess());
9921 // FIXME: Can this assert ever happen? Needs a test.
9922 assert(!NonTemplateMatch && "Multiple NonTemplateMatches");
9923 NonTemplateMatch = Method;
9929 FunctionTemplateDecl *FunTmpl = dyn_cast<FunctionTemplateDecl>(Prev);
9933 TemplateDeductionInfo Info(FailedCandidates.getLocation());
9934 FunctionDecl *Specialization = nullptr;
9935 if (TemplateDeductionResult TDK
9936 = DeduceTemplateArguments(FunTmpl,
9937 (HasExplicitTemplateArgs ? &TemplateArgs
9939 R, Specialization, Info)) {
9940 // Keep track of almost-matches.
9941 FailedCandidates.addCandidate()
9942 .set(P.getPair(), FunTmpl->getTemplatedDecl(),
9943 MakeDeductionFailureInfo(Context, TDK, Info));
9948 // Target attributes are part of the cuda function signature, so
9949 // the cuda target of the instantiated function must match that of its
9950 // template. Given that C++ template deduction does not take
9951 // target attributes into account, we reject candidates here that
9952 // have a different target.
9953 if (LangOpts.CUDA &&
9954 IdentifyCUDATarget(Specialization,
9955 /* IgnoreImplicitHDAttr = */ true) !=
9956 IdentifyCUDATarget(D.getDeclSpec().getAttributes())) {
9957 FailedCandidates.addCandidate().set(
9958 P.getPair(), FunTmpl->getTemplatedDecl(),
9959 MakeDeductionFailureInfo(Context, TDK_CUDATargetMismatch, Info));
9963 TemplateMatches.addDecl(Specialization, P.getAccess());
9966 FunctionDecl *Specialization = NonTemplateMatch;
9967 if (!Specialization) {
9968 // Find the most specialized function template specialization.
9969 UnresolvedSetIterator Result = getMostSpecialized(
9970 TemplateMatches.begin(), TemplateMatches.end(), FailedCandidates,
9971 D.getIdentifierLoc(),
9972 PDiag(diag::err_explicit_instantiation_not_known) << Name,
9973 PDiag(diag::err_explicit_instantiation_ambiguous) << Name,
9974 PDiag(diag::note_explicit_instantiation_candidate));
9976 if (Result == TemplateMatches.end())
9979 // Ignore access control bits, we don't need them for redeclaration checking.
9980 Specialization = cast<FunctionDecl>(*Result);
9983 // C++11 [except.spec]p4
9984 // In an explicit instantiation an exception-specification may be specified,
9985 // but is not required.
9986 // If an exception-specification is specified in an explicit instantiation
9987 // directive, it shall be compatible with the exception-specifications of
9988 // other declarations of that function.
9989 if (auto *FPT = R->getAs<FunctionProtoType>())
9990 if (FPT->hasExceptionSpec()) {
9992 diag::err_mismatched_exception_spec_explicit_instantiation;
9993 if (getLangOpts().MicrosoftExt)
9994 DiagID = diag::ext_mismatched_exception_spec_explicit_instantiation;
9995 bool Result = CheckEquivalentExceptionSpec(
9996 PDiag(DiagID) << Specialization->getType(),
9997 PDiag(diag::note_explicit_instantiation_here),
9998 Specialization->getType()->getAs<FunctionProtoType>(),
9999 Specialization->getLocation(), FPT, D.getBeginLoc());
10000 // In Microsoft mode, mismatching exception specifications just cause a
10002 if (!getLangOpts().MicrosoftExt && Result)
10006 if (Specialization->getTemplateSpecializationKind() == TSK_Undeclared) {
10007 Diag(D.getIdentifierLoc(),
10008 diag::err_explicit_instantiation_member_function_not_instantiated)
10010 << (Specialization->getTemplateSpecializationKind() ==
10011 TSK_ExplicitSpecialization);
10012 Diag(Specialization->getLocation(), diag::note_explicit_instantiation_here);
10016 FunctionDecl *PrevDecl = Specialization->getPreviousDecl();
10017 if (!PrevDecl && Specialization->isThisDeclarationADefinition())
10018 PrevDecl = Specialization;
10021 bool HasNoEffect = false;
10022 if (CheckSpecializationInstantiationRedecl(D.getIdentifierLoc(), TSK,
10024 PrevDecl->getTemplateSpecializationKind(),
10025 PrevDecl->getPointOfInstantiation(),
10029 // FIXME: We may still want to build some representation of this
10030 // explicit specialization.
10032 return (Decl*) nullptr;
10035 // HACK: libc++ has a bug where it attempts to explicitly instantiate the
10037 // valarray<size_t>::valarray(size_t) and
10038 // valarray<size_t>::~valarray()
10039 // that it declared to have internal linkage with the internal_linkage
10040 // attribute. Ignore the explicit instantiation declaration in this case.
10041 if (Specialization->hasAttr<InternalLinkageAttr>() &&
10042 TSK == TSK_ExplicitInstantiationDeclaration) {
10043 if (auto *RD = dyn_cast<CXXRecordDecl>(Specialization->getDeclContext()))
10044 if (RD->getIdentifier() && RD->getIdentifier()->isStr("valarray") &&
10045 RD->isInStdNamespace())
10046 return (Decl*) nullptr;
10049 ProcessDeclAttributeList(S, Specialization, D.getDeclSpec().getAttributes());
10051 // In MSVC mode, dllimported explicit instantiation definitions are treated as
10052 // instantiation declarations.
10053 if (TSK == TSK_ExplicitInstantiationDefinition &&
10054 Specialization->hasAttr<DLLImportAttr>() &&
10055 Context.getTargetInfo().getCXXABI().isMicrosoft())
10056 TSK = TSK_ExplicitInstantiationDeclaration;
10058 Specialization->setTemplateSpecializationKind(TSK, D.getIdentifierLoc());
10060 if (Specialization->isDefined()) {
10061 // Let the ASTConsumer know that this function has been explicitly
10062 // instantiated now, and its linkage might have changed.
10063 Consumer.HandleTopLevelDecl(DeclGroupRef(Specialization));
10064 } else if (TSK == TSK_ExplicitInstantiationDefinition)
10065 InstantiateFunctionDefinition(D.getIdentifierLoc(), Specialization);
10067 // C++0x [temp.explicit]p2:
10068 // If the explicit instantiation is for a member function, a member class
10069 // or a static data member of a class template specialization, the name of
10070 // the class template specialization in the qualified-id for the member
10071 // name shall be a simple-template-id.
10073 // C++98 has the same restriction, just worded differently.
10074 FunctionTemplateDecl *FunTmpl = Specialization->getPrimaryTemplate();
10075 if (D.getName().getKind() != UnqualifiedIdKind::IK_TemplateId && !FunTmpl &&
10076 D.getCXXScopeSpec().isSet() &&
10077 !ScopeSpecifierHasTemplateId(D.getCXXScopeSpec()))
10078 Diag(D.getIdentifierLoc(),
10079 diag::ext_explicit_instantiation_without_qualified_id)
10080 << Specialization << D.getCXXScopeSpec().getRange();
10082 CheckExplicitInstantiation(
10084 FunTmpl ? (NamedDecl *)FunTmpl
10085 : Specialization->getInstantiatedFromMemberFunction(),
10086 D.getIdentifierLoc(), D.getCXXScopeSpec().isSet(), TSK);
10088 // FIXME: Create some kind of ExplicitInstantiationDecl here.
10089 return (Decl*) nullptr;
10093 Sema::ActOnDependentTag(Scope *S, unsigned TagSpec, TagUseKind TUK,
10094 const CXXScopeSpec &SS, IdentifierInfo *Name,
10095 SourceLocation TagLoc, SourceLocation NameLoc) {
10096 // This has to hold, because SS is expected to be defined.
10097 assert(Name && "Expected a name in a dependent tag");
10099 NestedNameSpecifier *NNS = SS.getScopeRep();
10103 TagTypeKind Kind = TypeWithKeyword::getTagTypeKindForTypeSpec(TagSpec);
10105 if (TUK == TUK_Declaration || TUK == TUK_Definition) {
10106 Diag(NameLoc, diag::err_dependent_tag_decl)
10107 << (TUK == TUK_Definition) << Kind << SS.getRange();
10111 // Create the resulting type.
10112 ElaboratedTypeKeyword Kwd = TypeWithKeyword::getKeywordForTagTypeKind(Kind);
10113 QualType Result = Context.getDependentNameType(Kwd, NNS, Name);
10115 // Create type-source location information for this type.
10116 TypeLocBuilder TLB;
10117 DependentNameTypeLoc TL = TLB.push<DependentNameTypeLoc>(Result);
10118 TL.setElaboratedKeywordLoc(TagLoc);
10119 TL.setQualifierLoc(SS.getWithLocInContext(Context));
10120 TL.setNameLoc(NameLoc);
10121 return CreateParsedType(Result, TLB.getTypeSourceInfo(Context, Result));
10125 Sema::ActOnTypenameType(Scope *S, SourceLocation TypenameLoc,
10126 const CXXScopeSpec &SS, const IdentifierInfo &II,
10127 SourceLocation IdLoc) {
10128 if (SS.isInvalid())
10131 if (TypenameLoc.isValid() && S && !S->getTemplateParamParent())
10133 getLangOpts().CPlusPlus11 ?
10134 diag::warn_cxx98_compat_typename_outside_of_template :
10135 diag::ext_typename_outside_of_template)
10136 << FixItHint::CreateRemoval(TypenameLoc);
10138 NestedNameSpecifierLoc QualifierLoc = SS.getWithLocInContext(Context);
10139 TypeSourceInfo *TSI = nullptr;
10140 QualType T = CheckTypenameType(TypenameLoc.isValid()? ETK_Typename : ETK_None,
10141 TypenameLoc, QualifierLoc, II, IdLoc, &TSI,
10142 /*DeducedTSTContext=*/true);
10145 return CreateParsedType(T, TSI);
10149 Sema::ActOnTypenameType(Scope *S,
10150 SourceLocation TypenameLoc,
10151 const CXXScopeSpec &SS,
10152 SourceLocation TemplateKWLoc,
10153 TemplateTy TemplateIn,
10154 IdentifierInfo *TemplateII,
10155 SourceLocation TemplateIILoc,
10156 SourceLocation LAngleLoc,
10157 ASTTemplateArgsPtr TemplateArgsIn,
10158 SourceLocation RAngleLoc) {
10159 if (TypenameLoc.isValid() && S && !S->getTemplateParamParent())
10161 getLangOpts().CPlusPlus11 ?
10162 diag::warn_cxx98_compat_typename_outside_of_template :
10163 diag::ext_typename_outside_of_template)
10164 << FixItHint::CreateRemoval(TypenameLoc);
10166 // Strangely, non-type results are not ignored by this lookup, so the
10167 // program is ill-formed if it finds an injected-class-name.
10168 if (TypenameLoc.isValid()) {
10170 dyn_cast_or_null<CXXRecordDecl>(computeDeclContext(SS, false));
10171 if (LookupRD && LookupRD->getIdentifier() == TemplateII) {
10172 Diag(TemplateIILoc,
10173 diag::ext_out_of_line_qualified_id_type_names_constructor)
10174 << TemplateII << 0 /*injected-class-name used as template name*/
10175 << (TemplateKWLoc.isValid() ? 1 : 0 /*'template'/'typename' keyword*/);
10179 // Translate the parser's template argument list in our AST format.
10180 TemplateArgumentListInfo TemplateArgs(LAngleLoc, RAngleLoc);
10181 translateTemplateArguments(TemplateArgsIn, TemplateArgs);
10183 TemplateName Template = TemplateIn.get();
10184 if (DependentTemplateName *DTN = Template.getAsDependentTemplateName()) {
10185 // Construct a dependent template specialization type.
10186 assert(DTN && "dependent template has non-dependent name?");
10187 assert(DTN->getQualifier() == SS.getScopeRep());
10188 QualType T = Context.getDependentTemplateSpecializationType(ETK_Typename,
10189 DTN->getQualifier(),
10190 DTN->getIdentifier(),
10193 // Create source-location information for this type.
10194 TypeLocBuilder Builder;
10195 DependentTemplateSpecializationTypeLoc SpecTL
10196 = Builder.push<DependentTemplateSpecializationTypeLoc>(T);
10197 SpecTL.setElaboratedKeywordLoc(TypenameLoc);
10198 SpecTL.setQualifierLoc(SS.getWithLocInContext(Context));
10199 SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
10200 SpecTL.setTemplateNameLoc(TemplateIILoc);
10201 SpecTL.setLAngleLoc(LAngleLoc);
10202 SpecTL.setRAngleLoc(RAngleLoc);
10203 for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I)
10204 SpecTL.setArgLocInfo(I, TemplateArgs[I].getLocInfo());
10205 return CreateParsedType(T, Builder.getTypeSourceInfo(Context, T));
10208 QualType T = CheckTemplateIdType(Template, TemplateIILoc, TemplateArgs);
10212 // Provide source-location information for the template specialization type.
10213 TypeLocBuilder Builder;
10214 TemplateSpecializationTypeLoc SpecTL
10215 = Builder.push<TemplateSpecializationTypeLoc>(T);
10216 SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
10217 SpecTL.setTemplateNameLoc(TemplateIILoc);
10218 SpecTL.setLAngleLoc(LAngleLoc);
10219 SpecTL.setRAngleLoc(RAngleLoc);
10220 for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I)
10221 SpecTL.setArgLocInfo(I, TemplateArgs[I].getLocInfo());
10223 T = Context.getElaboratedType(ETK_Typename, SS.getScopeRep(), T);
10224 ElaboratedTypeLoc TL = Builder.push<ElaboratedTypeLoc>(T);
10225 TL.setElaboratedKeywordLoc(TypenameLoc);
10226 TL.setQualifierLoc(SS.getWithLocInContext(Context));
10228 TypeSourceInfo *TSI = Builder.getTypeSourceInfo(Context, T);
10229 return CreateParsedType(T, TSI);
10233 /// Determine whether this failed name lookup should be treated as being
10234 /// disabled by a usage of std::enable_if.
10235 static bool isEnableIf(NestedNameSpecifierLoc NNS, const IdentifierInfo &II,
10236 SourceRange &CondRange, Expr *&Cond) {
10237 // We must be looking for a ::type...
10238 if (!II.isStr("type"))
10241 // ... within an explicitly-written template specialization...
10242 if (!NNS || !NNS.getNestedNameSpecifier()->getAsType())
10244 TypeLoc EnableIfTy = NNS.getTypeLoc();
10245 TemplateSpecializationTypeLoc EnableIfTSTLoc =
10246 EnableIfTy.getAs<TemplateSpecializationTypeLoc>();
10247 if (!EnableIfTSTLoc || EnableIfTSTLoc.getNumArgs() == 0)
10249 const TemplateSpecializationType *EnableIfTST = EnableIfTSTLoc.getTypePtr();
10251 // ... which names a complete class template declaration...
10252 const TemplateDecl *EnableIfDecl =
10253 EnableIfTST->getTemplateName().getAsTemplateDecl();
10254 if (!EnableIfDecl || EnableIfTST->isIncompleteType())
10257 // ... called "enable_if".
10258 const IdentifierInfo *EnableIfII =
10259 EnableIfDecl->getDeclName().getAsIdentifierInfo();
10260 if (!EnableIfII || !EnableIfII->isStr("enable_if"))
10263 // Assume the first template argument is the condition.
10264 CondRange = EnableIfTSTLoc.getArgLoc(0).getSourceRange();
10266 // Dig out the condition.
10268 if (EnableIfTSTLoc.getArgLoc(0).getArgument().getKind()
10269 != TemplateArgument::Expression)
10272 Cond = EnableIfTSTLoc.getArgLoc(0).getSourceExpression();
10274 // Ignore Boolean literals; they add no value.
10275 if (isa<CXXBoolLiteralExpr>(Cond->IgnoreParenCasts()))
10282 Sema::CheckTypenameType(ElaboratedTypeKeyword Keyword,
10283 SourceLocation KeywordLoc,
10284 NestedNameSpecifierLoc QualifierLoc,
10285 const IdentifierInfo &II,
10286 SourceLocation IILoc,
10287 TypeSourceInfo **TSI,
10288 bool DeducedTSTContext) {
10289 QualType T = CheckTypenameType(Keyword, KeywordLoc, QualifierLoc, II, IILoc,
10290 DeducedTSTContext);
10294 *TSI = Context.CreateTypeSourceInfo(T);
10295 if (isa<DependentNameType>(T)) {
10296 DependentNameTypeLoc TL =
10297 (*TSI)->getTypeLoc().castAs<DependentNameTypeLoc>();
10298 TL.setElaboratedKeywordLoc(KeywordLoc);
10299 TL.setQualifierLoc(QualifierLoc);
10300 TL.setNameLoc(IILoc);
10302 ElaboratedTypeLoc TL = (*TSI)->getTypeLoc().castAs<ElaboratedTypeLoc>();
10303 TL.setElaboratedKeywordLoc(KeywordLoc);
10304 TL.setQualifierLoc(QualifierLoc);
10305 TL.getNamedTypeLoc().castAs<TypeSpecTypeLoc>().setNameLoc(IILoc);
10310 /// Build the type that describes a C++ typename specifier,
10311 /// e.g., "typename T::type".
10313 Sema::CheckTypenameType(ElaboratedTypeKeyword Keyword,
10314 SourceLocation KeywordLoc,
10315 NestedNameSpecifierLoc QualifierLoc,
10316 const IdentifierInfo &II,
10317 SourceLocation IILoc, bool DeducedTSTContext) {
10319 SS.Adopt(QualifierLoc);
10321 DeclContext *Ctx = nullptr;
10322 if (QualifierLoc) {
10323 Ctx = computeDeclContext(SS);
10325 // If the nested-name-specifier is dependent and couldn't be
10326 // resolved to a type, build a typename type.
10327 assert(QualifierLoc.getNestedNameSpecifier()->isDependent());
10328 return Context.getDependentNameType(Keyword,
10329 QualifierLoc.getNestedNameSpecifier(),
10333 // If the nested-name-specifier refers to the current instantiation,
10334 // the "typename" keyword itself is superfluous. In C++03, the
10335 // program is actually ill-formed. However, DR 382 (in C++0x CD1)
10336 // allows such extraneous "typename" keywords, and we retroactively
10337 // apply this DR to C++03 code with only a warning. In any case we continue.
10339 if (RequireCompleteDeclContext(SS, Ctx))
10343 DeclarationName Name(&II);
10344 LookupResult Result(*this, Name, IILoc, LookupOrdinaryName);
10346 LookupQualifiedName(Result, Ctx, SS);
10348 LookupName(Result, CurScope);
10349 unsigned DiagID = 0;
10350 Decl *Referenced = nullptr;
10351 switch (Result.getResultKind()) {
10352 case LookupResult::NotFound: {
10353 // If we're looking up 'type' within a template named 'enable_if', produce
10354 // a more specific diagnostic.
10355 SourceRange CondRange;
10356 Expr *Cond = nullptr;
10357 if (Ctx && isEnableIf(QualifierLoc, II, CondRange, Cond)) {
10358 // If we have a condition, narrow it down to the specific failed
10362 std::string FailedDescription;
10363 std::tie(FailedCond, FailedDescription) =
10364 findFailedBooleanCondition(Cond);
10366 Diag(FailedCond->getExprLoc(),
10367 diag::err_typename_nested_not_found_requirement)
10368 << FailedDescription
10369 << FailedCond->getSourceRange();
10373 Diag(CondRange.getBegin(),
10374 diag::err_typename_nested_not_found_enable_if)
10375 << Ctx << CondRange;
10379 DiagID = Ctx ? diag::err_typename_nested_not_found
10380 : diag::err_unknown_typename;
10384 case LookupResult::FoundUnresolvedValue: {
10385 // We found a using declaration that is a value. Most likely, the using
10386 // declaration itself is meant to have the 'typename' keyword.
10387 SourceRange FullRange(KeywordLoc.isValid() ? KeywordLoc : SS.getBeginLoc(),
10389 Diag(IILoc, diag::err_typename_refers_to_using_value_decl)
10390 << Name << Ctx << FullRange;
10391 if (UnresolvedUsingValueDecl *Using
10392 = dyn_cast<UnresolvedUsingValueDecl>(Result.getRepresentativeDecl())){
10393 SourceLocation Loc = Using->getQualifierLoc().getBeginLoc();
10394 Diag(Loc, diag::note_using_value_decl_missing_typename)
10395 << FixItHint::CreateInsertion(Loc, "typename ");
10398 // Fall through to create a dependent typename type, from which we can recover
10402 case LookupResult::NotFoundInCurrentInstantiation:
10403 // Okay, it's a member of an unknown instantiation.
10404 return Context.getDependentNameType(Keyword,
10405 QualifierLoc.getNestedNameSpecifier(),
10408 case LookupResult::Found:
10409 if (TypeDecl *Type = dyn_cast<TypeDecl>(Result.getFoundDecl())) {
10410 // C++ [class.qual]p2:
10411 // In a lookup in which function names are not ignored and the
10412 // nested-name-specifier nominates a class C, if the name specified
10413 // after the nested-name-specifier, when looked up in C, is the
10414 // injected-class-name of C [...] then the name is instead considered
10415 // to name the constructor of class C.
10417 // Unlike in an elaborated-type-specifier, function names are not ignored
10418 // in typename-specifier lookup. However, they are ignored in all the
10419 // contexts where we form a typename type with no keyword (that is, in
10420 // mem-initializer-ids, base-specifiers, and elaborated-type-specifiers).
10422 // FIXME: That's not strictly true: mem-initializer-id lookup does not
10423 // ignore functions, but that appears to be an oversight.
10424 auto *LookupRD = dyn_cast_or_null<CXXRecordDecl>(Ctx);
10425 auto *FoundRD = dyn_cast<CXXRecordDecl>(Type);
10426 if (Keyword == ETK_Typename && LookupRD && FoundRD &&
10427 FoundRD->isInjectedClassName() &&
10428 declaresSameEntity(LookupRD, cast<Decl>(FoundRD->getParent())))
10429 Diag(IILoc, diag::ext_out_of_line_qualified_id_type_names_constructor)
10430 << &II << 1 << 0 /*'typename' keyword used*/;
10432 // We found a type. Build an ElaboratedType, since the
10433 // typename-specifier was just sugar.
10434 MarkAnyDeclReferenced(Type->getLocation(), Type, /*OdrUse=*/false);
10435 return Context.getElaboratedType(Keyword,
10436 QualifierLoc.getNestedNameSpecifier(),
10437 Context.getTypeDeclType(Type));
10440 // C++ [dcl.type.simple]p2:
10441 // A type-specifier of the form
10442 // typename[opt] nested-name-specifier[opt] template-name
10443 // is a placeholder for a deduced class type [...].
10444 if (getLangOpts().CPlusPlus17) {
10445 if (auto *TD = getAsTypeTemplateDecl(Result.getFoundDecl())) {
10446 if (!DeducedTSTContext) {
10447 QualType T(QualifierLoc
10448 ? QualifierLoc.getNestedNameSpecifier()->getAsType()
10451 Diag(IILoc, diag::err_dependent_deduced_tst)
10452 << (int)getTemplateNameKindForDiagnostics(TemplateName(TD)) << T;
10454 Diag(IILoc, diag::err_deduced_tst)
10455 << (int)getTemplateNameKindForDiagnostics(TemplateName(TD));
10456 Diag(TD->getLocation(), diag::note_template_decl_here);
10459 return Context.getElaboratedType(
10460 Keyword, QualifierLoc.getNestedNameSpecifier(),
10461 Context.getDeducedTemplateSpecializationType(TemplateName(TD),
10462 QualType(), false));
10466 DiagID = Ctx ? diag::err_typename_nested_not_type
10467 : diag::err_typename_not_type;
10468 Referenced = Result.getFoundDecl();
10471 case LookupResult::FoundOverloaded:
10472 DiagID = Ctx ? diag::err_typename_nested_not_type
10473 : diag::err_typename_not_type;
10474 Referenced = *Result.begin();
10477 case LookupResult::Ambiguous:
10481 // If we get here, it's because name lookup did not find a
10482 // type. Emit an appropriate diagnostic and return an error.
10483 SourceRange FullRange(KeywordLoc.isValid() ? KeywordLoc : SS.getBeginLoc(),
10486 Diag(IILoc, DiagID) << FullRange << Name << Ctx;
10488 Diag(IILoc, DiagID) << FullRange << Name;
10490 Diag(Referenced->getLocation(),
10491 Ctx ? diag::note_typename_member_refers_here
10492 : diag::note_typename_refers_here)
10498 // See Sema::RebuildTypeInCurrentInstantiation
10499 class CurrentInstantiationRebuilder
10500 : public TreeTransform<CurrentInstantiationRebuilder> {
10501 SourceLocation Loc;
10502 DeclarationName Entity;
10505 typedef TreeTransform<CurrentInstantiationRebuilder> inherited;
10507 CurrentInstantiationRebuilder(Sema &SemaRef,
10508 SourceLocation Loc,
10509 DeclarationName Entity)
10510 : TreeTransform<CurrentInstantiationRebuilder>(SemaRef),
10511 Loc(Loc), Entity(Entity) { }
10513 /// Determine whether the given type \p T has already been
10516 /// For the purposes of type reconstruction, a type has already been
10517 /// transformed if it is NULL or if it is not dependent.
10518 bool AlreadyTransformed(QualType T) {
10519 return T.isNull() || !T->isDependentType();
10522 /// Returns the location of the entity whose type is being
10524 SourceLocation getBaseLocation() { return Loc; }
10526 /// Returns the name of the entity whose type is being rebuilt.
10527 DeclarationName getBaseEntity() { return Entity; }
10529 /// Sets the "base" location and entity when that
10530 /// information is known based on another transformation.
10531 void setBase(SourceLocation Loc, DeclarationName Entity) {
10533 this->Entity = Entity;
10536 ExprResult TransformLambdaExpr(LambdaExpr *E) {
10537 // Lambdas never need to be transformed.
10541 } // end anonymous namespace
10543 /// Rebuilds a type within the context of the current instantiation.
10545 /// The type \p T is part of the type of an out-of-line member definition of
10546 /// a class template (or class template partial specialization) that was parsed
10547 /// and constructed before we entered the scope of the class template (or
10548 /// partial specialization thereof). This routine will rebuild that type now
10549 /// that we have entered the declarator's scope, which may produce different
10550 /// canonical types, e.g.,
10553 /// template<typename T>
10555 /// typedef T* pointer;
10556 /// pointer data();
10559 /// template<typename T>
10560 /// typename X<T>::pointer X<T>::data() { ... }
10563 /// Here, the type "typename X<T>::pointer" will be created as a DependentNameType,
10564 /// since we do not know that we can look into X<T> when we parsed the type.
10565 /// This function will rebuild the type, performing the lookup of "pointer"
10566 /// in X<T> and returning an ElaboratedType whose canonical type is the same
10567 /// as the canonical type of T*, allowing the return types of the out-of-line
10568 /// definition and the declaration to match.
10569 TypeSourceInfo *Sema::RebuildTypeInCurrentInstantiation(TypeSourceInfo *T,
10570 SourceLocation Loc,
10571 DeclarationName Name) {
10572 if (!T || !T->getType()->isDependentType())
10575 CurrentInstantiationRebuilder Rebuilder(*this, Loc, Name);
10576 return Rebuilder.TransformType(T);
10579 ExprResult Sema::RebuildExprInCurrentInstantiation(Expr *E) {
10580 CurrentInstantiationRebuilder Rebuilder(*this, E->getExprLoc(),
10581 DeclarationName());
10582 return Rebuilder.TransformExpr(E);
10585 bool Sema::RebuildNestedNameSpecifierInCurrentInstantiation(CXXScopeSpec &SS) {
10586 if (SS.isInvalid())
10589 NestedNameSpecifierLoc QualifierLoc = SS.getWithLocInContext(Context);
10590 CurrentInstantiationRebuilder Rebuilder(*this, SS.getRange().getBegin(),
10591 DeclarationName());
10592 NestedNameSpecifierLoc Rebuilt
10593 = Rebuilder.TransformNestedNameSpecifierLoc(QualifierLoc);
10601 /// Rebuild the template parameters now that we know we're in a current
10603 bool Sema::RebuildTemplateParamsInCurrentInstantiation(
10604 TemplateParameterList *Params) {
10605 for (unsigned I = 0, N = Params->size(); I != N; ++I) {
10606 Decl *Param = Params->getParam(I);
10608 // There is nothing to rebuild in a type parameter.
10609 if (isa<TemplateTypeParmDecl>(Param))
10612 // Rebuild the template parameter list of a template template parameter.
10613 if (TemplateTemplateParmDecl *TTP
10614 = dyn_cast<TemplateTemplateParmDecl>(Param)) {
10615 if (RebuildTemplateParamsInCurrentInstantiation(
10616 TTP->getTemplateParameters()))
10622 // Rebuild the type of a non-type template parameter.
10623 NonTypeTemplateParmDecl *NTTP = cast<NonTypeTemplateParmDecl>(Param);
10624 TypeSourceInfo *NewTSI
10625 = RebuildTypeInCurrentInstantiation(NTTP->getTypeSourceInfo(),
10626 NTTP->getLocation(),
10627 NTTP->getDeclName());
10631 if (NewTSI->getType()->isUndeducedType()) {
10632 // C++17 [temp.dep.expr]p3:
10633 // An id-expression is type-dependent if it contains
10634 // - an identifier associated by name lookup with a non-type
10635 // template-parameter declared with a type that contains a
10636 // placeholder type (7.1.7.4),
10637 NewTSI = SubstAutoTypeSourceInfo(NewTSI, Context.DependentTy);
10640 if (NewTSI != NTTP->getTypeSourceInfo()) {
10641 NTTP->setTypeSourceInfo(NewTSI);
10642 NTTP->setType(NewTSI->getType());
10649 /// Produces a formatted string that describes the binding of
10650 /// template parameters to template arguments.
10652 Sema::getTemplateArgumentBindingsText(const TemplateParameterList *Params,
10653 const TemplateArgumentList &Args) {
10654 return getTemplateArgumentBindingsText(Params, Args.data(), Args.size());
10658 Sema::getTemplateArgumentBindingsText(const TemplateParameterList *Params,
10659 const TemplateArgument *Args,
10660 unsigned NumArgs) {
10661 SmallString<128> Str;
10662 llvm::raw_svector_ostream Out(Str);
10664 if (!Params || Params->size() == 0 || NumArgs == 0)
10665 return std::string();
10667 for (unsigned I = 0, N = Params->size(); I != N; ++I) {
10676 if (const IdentifierInfo *Id = Params->getParam(I)->getIdentifier()) {
10677 Out << Id->getName();
10683 Args[I].print(getPrintingPolicy(), Out);
10690 void Sema::MarkAsLateParsedTemplate(FunctionDecl *FD, Decl *FnD,
10691 CachedTokens &Toks) {
10695 auto LPT = std::make_unique<LateParsedTemplate>();
10697 // Take tokens to avoid allocations
10698 LPT->Toks.swap(Toks);
10700 LateParsedTemplateMap.insert(std::make_pair(FD, std::move(LPT)));
10702 FD->setLateTemplateParsed(true);
10705 void Sema::UnmarkAsLateParsedTemplate(FunctionDecl *FD) {
10708 FD->setLateTemplateParsed(false);
10711 bool Sema::IsInsideALocalClassWithinATemplateFunction() {
10712 DeclContext *DC = CurContext;
10715 if (CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(CurContext)) {
10716 const FunctionDecl *FD = RD->isLocalClass();
10717 return (FD && FD->getTemplatedKind() != FunctionDecl::TK_NonTemplate);
10718 } else if (DC->isTranslationUnit() || DC->isNamespace())
10721 DC = DC->getParent();
10727 /// Walk the path from which a declaration was instantiated, and check
10728 /// that every explicit specialization along that path is visible. This enforces
10729 /// C++ [temp.expl.spec]/6:
10731 /// If a template, a member template or a member of a class template is
10732 /// explicitly specialized then that specialization shall be declared before
10733 /// the first use of that specialization that would cause an implicit
10734 /// instantiation to take place, in every translation unit in which such a
10735 /// use occurs; no diagnostic is required.
10737 /// and also C++ [temp.class.spec]/1:
10739 /// A partial specialization shall be declared before the first use of a
10740 /// class template specialization that would make use of the partial
10741 /// specialization as the result of an implicit or explicit instantiation
10742 /// in every translation unit in which such a use occurs; no diagnostic is
10744 class ExplicitSpecializationVisibilityChecker {
10746 SourceLocation Loc;
10747 llvm::SmallVector<Module *, 8> Modules;
10750 ExplicitSpecializationVisibilityChecker(Sema &S, SourceLocation Loc)
10751 : S(S), Loc(Loc) {}
10753 void check(NamedDecl *ND) {
10754 if (auto *FD = dyn_cast<FunctionDecl>(ND))
10755 return checkImpl(FD);
10756 if (auto *RD = dyn_cast<CXXRecordDecl>(ND))
10757 return checkImpl(RD);
10758 if (auto *VD = dyn_cast<VarDecl>(ND))
10759 return checkImpl(VD);
10760 if (auto *ED = dyn_cast<EnumDecl>(ND))
10761 return checkImpl(ED);
10765 void diagnose(NamedDecl *D, bool IsPartialSpec) {
10766 auto Kind = IsPartialSpec ? Sema::MissingImportKind::PartialSpecialization
10767 : Sema::MissingImportKind::ExplicitSpecialization;
10768 const bool Recover = true;
10770 // If we got a custom set of modules (because only a subset of the
10771 // declarations are interesting), use them, otherwise let
10772 // diagnoseMissingImport intelligently pick some.
10773 if (Modules.empty())
10774 S.diagnoseMissingImport(Loc, D, Kind, Recover);
10776 S.diagnoseMissingImport(Loc, D, D->getLocation(), Modules, Kind, Recover);
10779 // Check a specific declaration. There are three problematic cases:
10781 // 1) The declaration is an explicit specialization of a template
10783 // 2) The declaration is an explicit specialization of a member of an
10784 // templated class.
10785 // 3) The declaration is an instantiation of a template, and that template
10786 // is an explicit specialization of a member of a templated class.
10788 // We don't need to go any deeper than that, as the instantiation of the
10789 // surrounding class / etc is not triggered by whatever triggered this
10790 // instantiation, and thus should be checked elsewhere.
10791 template<typename SpecDecl>
10792 void checkImpl(SpecDecl *Spec) {
10793 bool IsHiddenExplicitSpecialization = false;
10794 if (Spec->getTemplateSpecializationKind() == TSK_ExplicitSpecialization) {
10795 IsHiddenExplicitSpecialization =
10796 Spec->getMemberSpecializationInfo()
10797 ? !S.hasVisibleMemberSpecialization(Spec, &Modules)
10798 : !S.hasVisibleExplicitSpecialization(Spec, &Modules);
10800 checkInstantiated(Spec);
10803 if (IsHiddenExplicitSpecialization)
10804 diagnose(Spec->getMostRecentDecl(), false);
10807 void checkInstantiated(FunctionDecl *FD) {
10808 if (auto *TD = FD->getPrimaryTemplate())
10812 void checkInstantiated(CXXRecordDecl *RD) {
10813 auto *SD = dyn_cast<ClassTemplateSpecializationDecl>(RD);
10817 auto From = SD->getSpecializedTemplateOrPartial();
10818 if (auto *TD = From.dyn_cast<ClassTemplateDecl *>())
10820 else if (auto *TD =
10821 From.dyn_cast<ClassTemplatePartialSpecializationDecl *>()) {
10822 if (!S.hasVisibleDeclaration(TD))
10823 diagnose(TD, true);
10828 void checkInstantiated(VarDecl *RD) {
10829 auto *SD = dyn_cast<VarTemplateSpecializationDecl>(RD);
10833 auto From = SD->getSpecializedTemplateOrPartial();
10834 if (auto *TD = From.dyn_cast<VarTemplateDecl *>())
10836 else if (auto *TD =
10837 From.dyn_cast<VarTemplatePartialSpecializationDecl *>()) {
10838 if (!S.hasVisibleDeclaration(TD))
10839 diagnose(TD, true);
10844 void checkInstantiated(EnumDecl *FD) {}
10846 template<typename TemplDecl>
10847 void checkTemplate(TemplDecl *TD) {
10848 if (TD->isMemberSpecialization()) {
10849 if (!S.hasVisibleMemberSpecialization(TD, &Modules))
10850 diagnose(TD->getMostRecentDecl(), false);
10854 } // end anonymous namespace
10856 void Sema::checkSpecializationVisibility(SourceLocation Loc, NamedDecl *Spec) {
10857 if (!getLangOpts().Modules)
10860 ExplicitSpecializationVisibilityChecker(*this, Loc).check(Spec);
10863 /// Check whether a template partial specialization that we've discovered
10864 /// is hidden, and produce suitable diagnostics if so.
10865 void Sema::checkPartialSpecializationVisibility(SourceLocation Loc,
10867 llvm::SmallVector<Module *, 8> Modules;
10868 if (!hasVisibleDeclaration(Spec, &Modules))
10869 diagnoseMissingImport(Loc, Spec, Spec->getLocation(), Modules,
10870 MissingImportKind::PartialSpecialization,