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 /// \brief Determine whether the declaration found is acceptable as the name
50 /// of a template and, if so, return that template declaration. Otherwise,
53 /// Note that this may return an UnresolvedUsingValueDecl if AllowDependent
54 /// is true. In all other cases it will return a TemplateDecl (or null).
55 NamedDecl *Sema::getAsTemplateNameDecl(NamedDecl *D,
56 bool AllowFunctionTemplates,
57 bool AllowDependent) {
58 D = D->getUnderlyingDecl();
60 if (isa<TemplateDecl>(D)) {
61 if (!AllowFunctionTemplates && isa<FunctionTemplateDecl>(D))
67 if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(D)) {
68 // C++ [temp.local]p1:
69 // Like normal (non-template) classes, class templates have an
70 // injected-class-name (Clause 9). The injected-class-name
71 // can be used with or without a template-argument-list. When
72 // it is used without a template-argument-list, it is
73 // equivalent to the injected-class-name followed by the
74 // template-parameters of the class template enclosed in
75 // <>. When it is used with a template-argument-list, it
76 // refers to the specified class template specialization,
77 // which could be the current specialization or another
79 if (Record->isInjectedClassName()) {
80 Record = cast<CXXRecordDecl>(Record->getDeclContext());
81 if (Record->getDescribedClassTemplate())
82 return Record->getDescribedClassTemplate();
84 if (ClassTemplateSpecializationDecl *Spec
85 = dyn_cast<ClassTemplateSpecializationDecl>(Record))
86 return Spec->getSpecializedTemplate();
92 // 'using Dependent::foo;' can resolve to a template name.
93 // 'using typename Dependent::foo;' cannot (not even if 'foo' is an
94 // injected-class-name).
95 if (AllowDependent && isa<UnresolvedUsingValueDecl>(D))
101 void Sema::FilterAcceptableTemplateNames(LookupResult &R,
102 bool AllowFunctionTemplates,
103 bool AllowDependent) {
104 LookupResult::Filter filter = R.makeFilter();
105 while (filter.hasNext()) {
106 NamedDecl *Orig = filter.next();
107 if (!getAsTemplateNameDecl(Orig, AllowFunctionTemplates, AllowDependent))
113 bool Sema::hasAnyAcceptableTemplateNames(LookupResult &R,
114 bool AllowFunctionTemplates,
116 bool AllowNonTemplateFunctions) {
117 for (LookupResult::iterator I = R.begin(), IEnd = R.end(); I != IEnd; ++I) {
118 if (getAsTemplateNameDecl(*I, AllowFunctionTemplates, AllowDependent))
120 if (AllowNonTemplateFunctions &&
121 isa<FunctionDecl>((*I)->getUnderlyingDecl()))
128 TemplateNameKind Sema::isTemplateName(Scope *S,
130 bool hasTemplateKeyword,
131 const UnqualifiedId &Name,
132 ParsedType ObjectTypePtr,
133 bool EnteringContext,
134 TemplateTy &TemplateResult,
135 bool &MemberOfUnknownSpecialization) {
136 assert(getLangOpts().CPlusPlus && "No template names in C!");
138 DeclarationName TName;
139 MemberOfUnknownSpecialization = false;
141 switch (Name.getKind()) {
142 case UnqualifiedIdKind::IK_Identifier:
143 TName = DeclarationName(Name.Identifier);
146 case UnqualifiedIdKind::IK_OperatorFunctionId:
147 TName = Context.DeclarationNames.getCXXOperatorName(
148 Name.OperatorFunctionId.Operator);
151 case UnqualifiedIdKind::IK_LiteralOperatorId:
152 TName = Context.DeclarationNames.getCXXLiteralOperatorName(Name.Identifier);
156 return TNK_Non_template;
159 QualType ObjectType = ObjectTypePtr.get();
161 AssumedTemplateKind AssumedTemplate;
162 LookupResult R(*this, TName, Name.getBeginLoc(), LookupOrdinaryName);
163 if (LookupTemplateName(R, S, SS, ObjectType, EnteringContext,
164 MemberOfUnknownSpecialization, SourceLocation(),
166 return TNK_Non_template;
168 if (AssumedTemplate != AssumedTemplateKind::None) {
169 TemplateResult = TemplateTy::make(Context.getAssumedTemplateName(TName));
170 // Let the parser know whether we found nothing or found functions; if we
171 // found nothing, we want to more carefully check whether this is actually
172 // a function template name versus some other kind of undeclared identifier.
173 return AssumedTemplate == AssumedTemplateKind::FoundNothing
174 ? TNK_Undeclared_template
175 : TNK_Function_template;
179 return TNK_Non_template;
181 NamedDecl *D = nullptr;
182 if (R.isAmbiguous()) {
183 // If we got an ambiguity involving a non-function template, treat this
184 // as a template name, and pick an arbitrary template for error recovery.
185 bool AnyFunctionTemplates = false;
186 for (NamedDecl *FoundD : R) {
187 if (NamedDecl *FoundTemplate = getAsTemplateNameDecl(FoundD)) {
188 if (isa<FunctionTemplateDecl>(FoundTemplate))
189 AnyFunctionTemplates = true;
197 // If we didn't find any templates at all, this isn't a template name.
198 // Leave the ambiguity for a later lookup to diagnose.
199 if (!D && !AnyFunctionTemplates) {
200 R.suppressDiagnostics();
201 return TNK_Non_template;
204 // If the only templates were function templates, filter out the rest.
205 // We'll diagnose the ambiguity later.
207 FilterAcceptableTemplateNames(R);
210 // At this point, we have either picked a single template name declaration D
211 // or we have a non-empty set of results R containing either one template name
212 // declaration or a set of function templates.
214 TemplateName Template;
215 TemplateNameKind TemplateKind;
217 unsigned ResultCount = R.end() - R.begin();
218 if (!D && ResultCount > 1) {
219 // We assume that we'll preserve the qualifier from a function
220 // template name in other ways.
221 Template = Context.getOverloadedTemplateName(R.begin(), R.end());
222 TemplateKind = TNK_Function_template;
224 // We'll do this lookup again later.
225 R.suppressDiagnostics();
228 D = getAsTemplateNameDecl(*R.begin());
229 assert(D && "unambiguous result is not a template name");
232 if (isa<UnresolvedUsingValueDecl>(D)) {
233 // We don't yet know whether this is a template-name or not.
234 MemberOfUnknownSpecialization = true;
235 return TNK_Non_template;
238 TemplateDecl *TD = cast<TemplateDecl>(D);
240 if (SS.isSet() && !SS.isInvalid()) {
241 NestedNameSpecifier *Qualifier = SS.getScopeRep();
242 Template = Context.getQualifiedTemplateName(Qualifier,
243 hasTemplateKeyword, TD);
245 Template = TemplateName(TD);
248 if (isa<FunctionTemplateDecl>(TD)) {
249 TemplateKind = TNK_Function_template;
251 // We'll do this lookup again later.
252 R.suppressDiagnostics();
254 assert(isa<ClassTemplateDecl>(TD) || isa<TemplateTemplateParmDecl>(TD) ||
255 isa<TypeAliasTemplateDecl>(TD) || isa<VarTemplateDecl>(TD) ||
256 isa<BuiltinTemplateDecl>(TD) || isa<ConceptDecl>(TD));
258 isa<VarTemplateDecl>(TD) ? TNK_Var_template :
259 isa<ConceptDecl>(TD) ? TNK_Concept_template :
264 TemplateResult = TemplateTy::make(Template);
268 bool Sema::isDeductionGuideName(Scope *S, const IdentifierInfo &Name,
269 SourceLocation NameLoc,
270 ParsedTemplateTy *Template) {
272 bool MemberOfUnknownSpecialization = false;
274 // We could use redeclaration lookup here, but we don't need to: the
275 // syntactic form of a deduction guide is enough to identify it even
276 // if we can't look up the template name at all.
277 LookupResult R(*this, DeclarationName(&Name), NameLoc, LookupOrdinaryName);
278 if (LookupTemplateName(R, S, SS, /*ObjectType*/ QualType(),
279 /*EnteringContext*/ false,
280 MemberOfUnknownSpecialization))
283 if (R.empty()) return false;
284 if (R.isAmbiguous()) {
285 // FIXME: Diagnose an ambiguity if we find at least one template.
286 R.suppressDiagnostics();
290 // We only treat template-names that name type templates as valid deduction
292 TemplateDecl *TD = R.getAsSingle<TemplateDecl>();
293 if (!TD || !getAsTypeTemplateDecl(TD))
297 *Template = TemplateTy::make(TemplateName(TD));
301 bool Sema::DiagnoseUnknownTemplateName(const IdentifierInfo &II,
302 SourceLocation IILoc,
304 const CXXScopeSpec *SS,
305 TemplateTy &SuggestedTemplate,
306 TemplateNameKind &SuggestedKind) {
307 // We can't recover unless there's a dependent scope specifier preceding the
309 // FIXME: Typo correction?
310 if (!SS || !SS->isSet() || !isDependentScopeSpecifier(*SS) ||
311 computeDeclContext(*SS))
314 // The code is missing a 'template' keyword prior to the dependent template
316 NestedNameSpecifier *Qualifier = (NestedNameSpecifier*)SS->getScopeRep();
317 Diag(IILoc, diag::err_template_kw_missing)
318 << Qualifier << II.getName()
319 << FixItHint::CreateInsertion(IILoc, "template ");
321 = TemplateTy::make(Context.getDependentTemplateName(Qualifier, &II));
322 SuggestedKind = TNK_Dependent_template_name;
326 bool Sema::LookupTemplateName(LookupResult &Found,
327 Scope *S, CXXScopeSpec &SS,
329 bool EnteringContext,
330 bool &MemberOfUnknownSpecialization,
331 SourceLocation TemplateKWLoc,
332 AssumedTemplateKind *ATK) {
334 *ATK = AssumedTemplateKind::None;
336 Found.setTemplateNameLookup(true);
338 // Determine where to perform name lookup
339 MemberOfUnknownSpecialization = false;
340 DeclContext *LookupCtx = nullptr;
341 bool IsDependent = false;
342 if (!ObjectType.isNull()) {
343 // This nested-name-specifier occurs in a member access expression, e.g.,
344 // x->B::f, and we are looking into the type of the object.
345 assert(!SS.isSet() && "ObjectType and scope specifier cannot coexist");
346 LookupCtx = computeDeclContext(ObjectType);
347 IsDependent = !LookupCtx && ObjectType->isDependentType();
348 assert((IsDependent || !ObjectType->isIncompleteType() ||
349 ObjectType->castAs<TagType>()->isBeingDefined()) &&
350 "Caller should have completed object type");
352 // Template names cannot appear inside an Objective-C class or object type
355 // FIXME: This is wrong. For example:
357 // template<typename T> using Vec = T __attribute__((ext_vector_type(4)));
359 // vi.Vec<int>::~Vec<int>();
361 // ... should be accepted but we will not treat 'Vec' as a template name
362 // here. The right thing to do would be to check if the name is a valid
363 // vector component name, and look up a template name if not. And similarly
364 // for lookups into Objective-C class and object types, where the same
365 // problem can arise.
366 if (ObjectType->isObjCObjectOrInterfaceType() ||
367 ObjectType->isVectorType()) {
371 } else if (SS.isSet()) {
372 // This nested-name-specifier occurs after another nested-name-specifier,
373 // so long into the context associated with the prior nested-name-specifier.
374 LookupCtx = computeDeclContext(SS, EnteringContext);
375 IsDependent = !LookupCtx;
377 // The declaration context must be complete.
378 if (LookupCtx && RequireCompleteDeclContext(SS, LookupCtx))
382 bool ObjectTypeSearchedInScope = false;
383 bool AllowFunctionTemplatesInLookup = true;
385 // Perform "qualified" name lookup into the declaration context we
386 // computed, which is either the type of the base of a member access
387 // expression or the declaration context associated with a prior
388 // nested-name-specifier.
389 LookupQualifiedName(Found, LookupCtx);
391 // FIXME: The C++ standard does not clearly specify what happens in the
392 // case where the object type is dependent, and implementations vary. In
393 // Clang, we treat a name after a . or -> as a template-name if lookup
394 // finds a non-dependent member or member of the current instantiation that
395 // is a type template, or finds no such members and lookup in the context
396 // of the postfix-expression finds a type template. In the latter case, the
397 // name is nonetheless dependent, and we may resolve it to a member of an
398 // unknown specialization when we come to instantiate the template.
399 IsDependent |= Found.wasNotFoundInCurrentInstantiation();
402 if (!SS.isSet() && (ObjectType.isNull() || Found.empty())) {
403 // C++ [basic.lookup.classref]p1:
404 // In a class member access expression (5.2.5), if the . or -> token is
405 // immediately followed by an identifier followed by a <, the
406 // identifier must be looked up to determine whether the < is the
407 // beginning of a template argument list (14.2) or a less-than operator.
408 // The identifier is first looked up in the class of the object
409 // expression. If the identifier is not found, it is then looked up in
410 // the context of the entire postfix-expression and shall name a class
413 LookupName(Found, S);
415 if (!ObjectType.isNull()) {
416 // FIXME: We should filter out all non-type templates here, particularly
417 // variable templates and concepts. But the exclusion of alias templates
418 // and template template parameters is a wording defect.
419 AllowFunctionTemplatesInLookup = false;
420 ObjectTypeSearchedInScope = true;
423 IsDependent |= Found.wasNotFoundInCurrentInstantiation();
426 if (Found.isAmbiguous())
429 if (ATK && !SS.isSet() && ObjectType.isNull() && TemplateKWLoc.isInvalid()) {
430 // C++2a [temp.names]p2:
431 // A name is also considered to refer to a template if it is an
432 // unqualified-id followed by a < and name lookup finds either one or more
433 // functions or finds nothing.
435 // To keep our behavior consistent, we apply the "finds nothing" part in
436 // all language modes, and diagnose the empty lookup in ActOnCallExpr if we
437 // successfully form a call to an undeclared template-id.
439 getLangOpts().CPlusPlus2a &&
440 std::all_of(Found.begin(), Found.end(), [](NamedDecl *ND) {
441 return isa<FunctionDecl>(ND->getUnderlyingDecl());
443 if (AllFunctions || (Found.empty() && !IsDependent)) {
444 // If lookup found any functions, or if this is a name that can only be
445 // used for a function, then strongly assume this is a function
447 *ATK = (Found.empty() && Found.getLookupName().isIdentifier())
448 ? AssumedTemplateKind::FoundNothing
449 : AssumedTemplateKind::FoundFunctions;
455 if (Found.empty() && !IsDependent) {
456 // If we did not find any names, attempt to correct any typos.
457 DeclarationName Name = Found.getLookupName();
459 // Simple filter callback that, for keywords, only accepts the C++ *_cast
460 DefaultFilterCCC FilterCCC{};
461 FilterCCC.WantTypeSpecifiers = false;
462 FilterCCC.WantExpressionKeywords = false;
463 FilterCCC.WantRemainingKeywords = false;
464 FilterCCC.WantCXXNamedCasts = true;
465 if (TypoCorrection Corrected =
466 CorrectTypo(Found.getLookupNameInfo(), Found.getLookupKind(), S,
467 &SS, FilterCCC, CTK_ErrorRecovery, LookupCtx)) {
468 if (auto *ND = Corrected.getFoundDecl())
470 FilterAcceptableTemplateNames(Found);
471 if (Found.isAmbiguous()) {
473 } else if (!Found.empty()) {
474 Found.setLookupName(Corrected.getCorrection());
476 std::string CorrectedStr(Corrected.getAsString(getLangOpts()));
477 bool DroppedSpecifier = Corrected.WillReplaceSpecifier() &&
478 Name.getAsString() == CorrectedStr;
479 diagnoseTypo(Corrected, PDiag(diag::err_no_member_template_suggest)
480 << Name << LookupCtx << DroppedSpecifier
483 diagnoseTypo(Corrected, PDiag(diag::err_no_template_suggest) << Name);
489 NamedDecl *ExampleLookupResult =
490 Found.empty() ? nullptr : Found.getRepresentativeDecl();
491 FilterAcceptableTemplateNames(Found, AllowFunctionTemplatesInLookup);
494 MemberOfUnknownSpecialization = true;
498 // If a 'template' keyword was used, a lookup that finds only non-template
499 // names is an error.
500 if (ExampleLookupResult && TemplateKWLoc.isValid()) {
501 Diag(Found.getNameLoc(), diag::err_template_kw_refers_to_non_template)
502 << Found.getLookupName() << SS.getRange();
503 Diag(ExampleLookupResult->getUnderlyingDecl()->getLocation(),
504 diag::note_template_kw_refers_to_non_template)
505 << Found.getLookupName();
512 if (S && !ObjectType.isNull() && !ObjectTypeSearchedInScope &&
513 !getLangOpts().CPlusPlus11) {
514 // C++03 [basic.lookup.classref]p1:
515 // [...] If the lookup in the class of the object expression finds a
516 // template, the name is also looked up in the context of the entire
517 // postfix-expression and [...]
519 // Note: C++11 does not perform this second lookup.
520 LookupResult FoundOuter(*this, Found.getLookupName(), Found.getNameLoc(),
522 FoundOuter.setTemplateNameLookup(true);
523 LookupName(FoundOuter, S);
524 // FIXME: We silently accept an ambiguous lookup here, in violation of
526 FilterAcceptableTemplateNames(FoundOuter, /*AllowFunctionTemplates=*/false);
528 NamedDecl *OuterTemplate;
529 if (FoundOuter.empty()) {
530 // - if the name is not found, the name found in the class of the
531 // object expression is used, otherwise
532 } else if (FoundOuter.isAmbiguous() || !FoundOuter.isSingleResult() ||
534 getAsTemplateNameDecl(FoundOuter.getFoundDecl()))) {
535 // - if the name is found in the context of the entire
536 // postfix-expression and does not name a class template, the name
537 // found in the class of the object expression is used, otherwise
539 } else if (!Found.isSuppressingDiagnostics()) {
540 // - if the name found is a class template, it must refer to the same
541 // entity as the one found in the class of the object expression,
542 // otherwise the program is ill-formed.
543 if (!Found.isSingleResult() ||
544 getAsTemplateNameDecl(Found.getFoundDecl())->getCanonicalDecl() !=
545 OuterTemplate->getCanonicalDecl()) {
546 Diag(Found.getNameLoc(),
547 diag::ext_nested_name_member_ref_lookup_ambiguous)
548 << Found.getLookupName()
550 Diag(Found.getRepresentativeDecl()->getLocation(),
551 diag::note_ambig_member_ref_object_type)
553 Diag(FoundOuter.getFoundDecl()->getLocation(),
554 diag::note_ambig_member_ref_scope);
556 // Recover by taking the template that we found in the object
557 // expression's type.
565 void Sema::diagnoseExprIntendedAsTemplateName(Scope *S, ExprResult TemplateName,
567 SourceLocation Greater) {
568 if (TemplateName.isInvalid())
571 DeclarationNameInfo NameInfo;
573 LookupNameKind LookupKind;
575 DeclContext *LookupCtx = nullptr;
576 NamedDecl *Found = nullptr;
577 bool MissingTemplateKeyword = false;
579 // Figure out what name we looked up.
580 if (auto *DRE = dyn_cast<DeclRefExpr>(TemplateName.get())) {
581 NameInfo = DRE->getNameInfo();
582 SS.Adopt(DRE->getQualifierLoc());
583 LookupKind = LookupOrdinaryName;
584 Found = DRE->getFoundDecl();
585 } else if (auto *ME = dyn_cast<MemberExpr>(TemplateName.get())) {
586 NameInfo = ME->getMemberNameInfo();
587 SS.Adopt(ME->getQualifierLoc());
588 LookupKind = LookupMemberName;
589 LookupCtx = ME->getBase()->getType()->getAsCXXRecordDecl();
590 Found = ME->getMemberDecl();
591 } else if (auto *DSDRE =
592 dyn_cast<DependentScopeDeclRefExpr>(TemplateName.get())) {
593 NameInfo = DSDRE->getNameInfo();
594 SS.Adopt(DSDRE->getQualifierLoc());
595 MissingTemplateKeyword = true;
596 } else if (auto *DSME =
597 dyn_cast<CXXDependentScopeMemberExpr>(TemplateName.get())) {
598 NameInfo = DSME->getMemberNameInfo();
599 SS.Adopt(DSME->getQualifierLoc());
600 MissingTemplateKeyword = true;
602 llvm_unreachable("unexpected kind of potential template name");
605 // If this is a dependent-scope lookup, diagnose that the 'template' keyword
607 if (MissingTemplateKeyword) {
608 Diag(NameInfo.getBeginLoc(), diag::err_template_kw_missing)
609 << "" << NameInfo.getName().getAsString() << SourceRange(Less, Greater);
613 // Try to correct the name by looking for templates and C++ named casts.
614 struct TemplateCandidateFilter : CorrectionCandidateCallback {
616 TemplateCandidateFilter(Sema &S) : S(S) {
617 WantTypeSpecifiers = false;
618 WantExpressionKeywords = false;
619 WantRemainingKeywords = false;
620 WantCXXNamedCasts = true;
622 bool ValidateCandidate(const TypoCorrection &Candidate) override {
623 if (auto *ND = Candidate.getCorrectionDecl())
624 return S.getAsTemplateNameDecl(ND);
625 return Candidate.isKeyword();
628 std::unique_ptr<CorrectionCandidateCallback> clone() override {
629 return std::make_unique<TemplateCandidateFilter>(*this);
633 DeclarationName Name = NameInfo.getName();
634 TemplateCandidateFilter CCC(*this);
635 if (TypoCorrection Corrected = CorrectTypo(NameInfo, LookupKind, S, &SS, CCC,
636 CTK_ErrorRecovery, LookupCtx)) {
637 auto *ND = Corrected.getFoundDecl();
639 ND = getAsTemplateNameDecl(ND);
640 if (ND || Corrected.isKeyword()) {
642 std::string CorrectedStr(Corrected.getAsString(getLangOpts()));
643 bool DroppedSpecifier = Corrected.WillReplaceSpecifier() &&
644 Name.getAsString() == CorrectedStr;
645 diagnoseTypo(Corrected,
646 PDiag(diag::err_non_template_in_member_template_id_suggest)
647 << Name << LookupCtx << DroppedSpecifier
648 << SS.getRange(), false);
650 diagnoseTypo(Corrected,
651 PDiag(diag::err_non_template_in_template_id_suggest)
655 Diag(Found->getLocation(),
656 diag::note_non_template_in_template_id_found);
661 Diag(NameInfo.getLoc(), diag::err_non_template_in_template_id)
662 << Name << SourceRange(Less, Greater);
664 Diag(Found->getLocation(), diag::note_non_template_in_template_id_found);
667 /// ActOnDependentIdExpression - Handle a dependent id-expression that
668 /// was just parsed. This is only possible with an explicit scope
669 /// specifier naming a dependent type.
671 Sema::ActOnDependentIdExpression(const CXXScopeSpec &SS,
672 SourceLocation TemplateKWLoc,
673 const DeclarationNameInfo &NameInfo,
674 bool isAddressOfOperand,
675 const TemplateArgumentListInfo *TemplateArgs) {
676 DeclContext *DC = getFunctionLevelDeclContext();
678 // C++11 [expr.prim.general]p12:
679 // An id-expression that denotes a non-static data member or non-static
680 // member function of a class can only be used:
682 // - if that id-expression denotes a non-static data member and it
683 // appears in an unevaluated operand.
685 // If this might be the case, form a DependentScopeDeclRefExpr instead of a
686 // CXXDependentScopeMemberExpr. The former can instantiate to either
687 // DeclRefExpr or MemberExpr depending on lookup results, while the latter is
688 // always a MemberExpr.
689 bool MightBeCxx11UnevalField =
690 getLangOpts().CPlusPlus11 && isUnevaluatedContext();
692 // Check if the nested name specifier is an enum type.
694 if (NestedNameSpecifier *NNS = SS.getScopeRep())
695 IsEnum = dyn_cast_or_null<EnumType>(NNS->getAsType());
697 if (!MightBeCxx11UnevalField && !isAddressOfOperand && !IsEnum &&
698 isa<CXXMethodDecl>(DC) && cast<CXXMethodDecl>(DC)->isInstance()) {
699 QualType ThisType = cast<CXXMethodDecl>(DC)->getThisType();
701 // Since the 'this' expression is synthesized, we don't need to
702 // perform the double-lookup check.
703 NamedDecl *FirstQualifierInScope = nullptr;
705 return CXXDependentScopeMemberExpr::Create(
706 Context, /*This*/ nullptr, ThisType, /*IsArrow*/ true,
707 /*Op*/ SourceLocation(), SS.getWithLocInContext(Context), TemplateKWLoc,
708 FirstQualifierInScope, NameInfo, TemplateArgs);
711 return BuildDependentDeclRefExpr(SS, TemplateKWLoc, NameInfo, TemplateArgs);
715 Sema::BuildDependentDeclRefExpr(const CXXScopeSpec &SS,
716 SourceLocation TemplateKWLoc,
717 const DeclarationNameInfo &NameInfo,
718 const TemplateArgumentListInfo *TemplateArgs) {
719 // DependentScopeDeclRefExpr::Create requires a valid QualifierLoc
720 NestedNameSpecifierLoc QualifierLoc = SS.getWithLocInContext(Context);
724 return DependentScopeDeclRefExpr::Create(
725 Context, QualifierLoc, TemplateKWLoc, NameInfo, TemplateArgs);
729 /// Determine whether we would be unable to instantiate this template (because
730 /// it either has no definition, or is in the process of being instantiated).
731 bool Sema::DiagnoseUninstantiableTemplate(SourceLocation PointOfInstantiation,
732 NamedDecl *Instantiation,
733 bool InstantiatedFromMember,
734 const NamedDecl *Pattern,
735 const NamedDecl *PatternDef,
736 TemplateSpecializationKind TSK,
737 bool Complain /*= true*/) {
738 assert(isa<TagDecl>(Instantiation) || isa<FunctionDecl>(Instantiation) ||
739 isa<VarDecl>(Instantiation));
741 bool IsEntityBeingDefined = false;
742 if (const TagDecl *TD = dyn_cast_or_null<TagDecl>(PatternDef))
743 IsEntityBeingDefined = TD->isBeingDefined();
745 if (PatternDef && !IsEntityBeingDefined) {
746 NamedDecl *SuggestedDef = nullptr;
747 if (!hasVisibleDefinition(const_cast<NamedDecl*>(PatternDef), &SuggestedDef,
748 /*OnlyNeedComplete*/false)) {
749 // If we're allowed to diagnose this and recover, do so.
750 bool Recover = Complain && !isSFINAEContext();
752 diagnoseMissingImport(PointOfInstantiation, SuggestedDef,
753 Sema::MissingImportKind::Definition, Recover);
759 if (!Complain || (PatternDef && PatternDef->isInvalidDecl()))
762 llvm::Optional<unsigned> Note;
763 QualType InstantiationTy;
764 if (TagDecl *TD = dyn_cast<TagDecl>(Instantiation))
765 InstantiationTy = Context.getTypeDeclType(TD);
767 Diag(PointOfInstantiation,
768 diag::err_template_instantiate_within_definition)
769 << /*implicit|explicit*/(TSK != TSK_ImplicitInstantiation)
771 // Not much point in noting the template declaration here, since
772 // we're lexically inside it.
773 Instantiation->setInvalidDecl();
774 } else if (InstantiatedFromMember) {
775 if (isa<FunctionDecl>(Instantiation)) {
776 Diag(PointOfInstantiation,
777 diag::err_explicit_instantiation_undefined_member)
778 << /*member function*/ 1 << Instantiation->getDeclName()
779 << Instantiation->getDeclContext();
780 Note = diag::note_explicit_instantiation_here;
782 assert(isa<TagDecl>(Instantiation) && "Must be a TagDecl!");
783 Diag(PointOfInstantiation,
784 diag::err_implicit_instantiate_member_undefined)
786 Note = diag::note_member_declared_at;
789 if (isa<FunctionDecl>(Instantiation)) {
790 Diag(PointOfInstantiation,
791 diag::err_explicit_instantiation_undefined_func_template)
793 Note = diag::note_explicit_instantiation_here;
794 } else if (isa<TagDecl>(Instantiation)) {
795 Diag(PointOfInstantiation, diag::err_template_instantiate_undefined)
796 << (TSK != TSK_ImplicitInstantiation)
798 Note = diag::note_template_decl_here;
800 assert(isa<VarDecl>(Instantiation) && "Must be a VarDecl!");
801 if (isa<VarTemplateSpecializationDecl>(Instantiation)) {
802 Diag(PointOfInstantiation,
803 diag::err_explicit_instantiation_undefined_var_template)
805 Instantiation->setInvalidDecl();
807 Diag(PointOfInstantiation,
808 diag::err_explicit_instantiation_undefined_member)
809 << /*static data member*/ 2 << Instantiation->getDeclName()
810 << Instantiation->getDeclContext();
811 Note = diag::note_explicit_instantiation_here;
814 if (Note) // Diagnostics were emitted.
815 Diag(Pattern->getLocation(), Note.getValue());
817 // In general, Instantiation isn't marked invalid to get more than one
818 // error for multiple undefined instantiations. But the code that does
819 // explicit declaration -> explicit definition conversion can't handle
820 // invalid declarations, so mark as invalid in that case.
821 if (TSK == TSK_ExplicitInstantiationDeclaration)
822 Instantiation->setInvalidDecl();
826 /// DiagnoseTemplateParameterShadow - Produce a diagnostic complaining
827 /// that the template parameter 'PrevDecl' is being shadowed by a new
828 /// declaration at location Loc. Returns true to indicate that this is
829 /// an error, and false otherwise.
830 void Sema::DiagnoseTemplateParameterShadow(SourceLocation Loc, Decl *PrevDecl) {
831 assert(PrevDecl->isTemplateParameter() && "Not a template parameter");
833 // C++ [temp.local]p4:
834 // A template-parameter shall not be redeclared within its
835 // scope (including nested scopes).
837 // Make this a warning when MSVC compatibility is requested.
838 unsigned DiagId = getLangOpts().MSVCCompat ? diag::ext_template_param_shadow
839 : diag::err_template_param_shadow;
840 Diag(Loc, DiagId) << cast<NamedDecl>(PrevDecl)->getDeclName();
841 Diag(PrevDecl->getLocation(), diag::note_template_param_here);
844 /// AdjustDeclIfTemplate - If the given decl happens to be a template, reset
845 /// the parameter D to reference the templated declaration and return a pointer
846 /// to the template declaration. Otherwise, do nothing to D and return null.
847 TemplateDecl *Sema::AdjustDeclIfTemplate(Decl *&D) {
848 if (TemplateDecl *Temp = dyn_cast_or_null<TemplateDecl>(D)) {
849 D = Temp->getTemplatedDecl();
855 ParsedTemplateArgument ParsedTemplateArgument::getTemplatePackExpansion(
856 SourceLocation EllipsisLoc) const {
857 assert(Kind == Template &&
858 "Only template template arguments can be pack expansions here");
859 assert(getAsTemplate().get().containsUnexpandedParameterPack() &&
860 "Template template argument pack expansion without packs");
861 ParsedTemplateArgument Result(*this);
862 Result.EllipsisLoc = EllipsisLoc;
866 static TemplateArgumentLoc translateTemplateArgument(Sema &SemaRef,
867 const ParsedTemplateArgument &Arg) {
869 switch (Arg.getKind()) {
870 case ParsedTemplateArgument::Type: {
872 QualType T = SemaRef.GetTypeFromParser(Arg.getAsType(), &DI);
874 DI = SemaRef.Context.getTrivialTypeSourceInfo(T, Arg.getLocation());
875 return TemplateArgumentLoc(TemplateArgument(T), DI);
878 case ParsedTemplateArgument::NonType: {
879 Expr *E = static_cast<Expr *>(Arg.getAsExpr());
880 return TemplateArgumentLoc(TemplateArgument(E), E);
883 case ParsedTemplateArgument::Template: {
884 TemplateName Template = Arg.getAsTemplate().get();
885 TemplateArgument TArg;
886 if (Arg.getEllipsisLoc().isValid())
887 TArg = TemplateArgument(Template, Optional<unsigned int>());
890 return TemplateArgumentLoc(TArg,
891 Arg.getScopeSpec().getWithLocInContext(
894 Arg.getEllipsisLoc());
898 llvm_unreachable("Unhandled parsed template argument");
901 /// Translates template arguments as provided by the parser
902 /// into template arguments used by semantic analysis.
903 void Sema::translateTemplateArguments(const ASTTemplateArgsPtr &TemplateArgsIn,
904 TemplateArgumentListInfo &TemplateArgs) {
905 for (unsigned I = 0, Last = TemplateArgsIn.size(); I != Last; ++I)
906 TemplateArgs.addArgument(translateTemplateArgument(*this,
910 static void maybeDiagnoseTemplateParameterShadow(Sema &SemaRef, Scope *S,
912 IdentifierInfo *Name) {
913 NamedDecl *PrevDecl = SemaRef.LookupSingleName(
914 S, Name, Loc, Sema::LookupOrdinaryName, Sema::ForVisibleRedeclaration);
915 if (PrevDecl && PrevDecl->isTemplateParameter())
916 SemaRef.DiagnoseTemplateParameterShadow(Loc, PrevDecl);
919 /// Convert a parsed type into a parsed template argument. This is mostly
920 /// trivial, except that we may have parsed a C++17 deduced class template
921 /// specialization type, in which case we should form a template template
922 /// argument instead of a type template argument.
923 ParsedTemplateArgument Sema::ActOnTemplateTypeArgument(TypeResult ParsedType) {
924 TypeSourceInfo *TInfo;
925 QualType T = GetTypeFromParser(ParsedType.get(), &TInfo);
927 return ParsedTemplateArgument();
928 assert(TInfo && "template argument with no location");
930 // If we might have formed a deduced template specialization type, convert
931 // it to a template template argument.
932 if (getLangOpts().CPlusPlus17) {
933 TypeLoc TL = TInfo->getTypeLoc();
934 SourceLocation EllipsisLoc;
935 if (auto PET = TL.getAs<PackExpansionTypeLoc>()) {
936 EllipsisLoc = PET.getEllipsisLoc();
937 TL = PET.getPatternLoc();
941 if (auto ET = TL.getAs<ElaboratedTypeLoc>()) {
942 SS.Adopt(ET.getQualifierLoc());
943 TL = ET.getNamedTypeLoc();
946 if (auto DTST = TL.getAs<DeducedTemplateSpecializationTypeLoc>()) {
947 TemplateName Name = DTST.getTypePtr()->getTemplateName();
949 Name = Context.getQualifiedTemplateName(SS.getScopeRep(),
950 /*HasTemplateKeyword*/ false,
951 Name.getAsTemplateDecl());
952 ParsedTemplateArgument Result(SS, TemplateTy::make(Name),
953 DTST.getTemplateNameLoc());
954 if (EllipsisLoc.isValid())
955 Result = Result.getTemplatePackExpansion(EllipsisLoc);
960 // This is a normal type template argument. Note, if the type template
961 // argument is an injected-class-name for a template, it has a dual nature
962 // and can be used as either a type or a template. We handle that in
963 // convertTypeTemplateArgumentToTemplate.
964 return ParsedTemplateArgument(ParsedTemplateArgument::Type,
965 ParsedType.get().getAsOpaquePtr(),
966 TInfo->getTypeLoc().getBeginLoc());
969 /// ActOnTypeParameter - Called when a C++ template type parameter
970 /// (e.g., "typename T") has been parsed. Typename specifies whether
971 /// the keyword "typename" was used to declare the type parameter
972 /// (otherwise, "class" was used), and KeyLoc is the location of the
973 /// "class" or "typename" keyword. ParamName is the name of the
974 /// parameter (NULL indicates an unnamed template parameter) and
975 /// ParamNameLoc is the location of the parameter name (if any).
976 /// If the type parameter has a default argument, it will be added
977 /// later via ActOnTypeParameterDefault.
978 NamedDecl *Sema::ActOnTypeParameter(Scope *S, bool Typename,
979 SourceLocation EllipsisLoc,
980 SourceLocation KeyLoc,
981 IdentifierInfo *ParamName,
982 SourceLocation ParamNameLoc,
983 unsigned Depth, unsigned Position,
984 SourceLocation EqualLoc,
985 ParsedType DefaultArg,
986 bool HasTypeConstraint) {
987 assert(S->isTemplateParamScope() &&
988 "Template type parameter not in template parameter scope!");
990 bool IsParameterPack = EllipsisLoc.isValid();
991 TemplateTypeParmDecl *Param
992 = TemplateTypeParmDecl::Create(Context, Context.getTranslationUnitDecl(),
993 KeyLoc, ParamNameLoc, Depth, Position,
994 ParamName, Typename, IsParameterPack,
996 Param->setAccess(AS_public);
998 if (Param->isParameterPack())
999 if (auto *LSI = getEnclosingLambda())
1000 LSI->LocalPacks.push_back(Param);
1003 maybeDiagnoseTemplateParameterShadow(*this, S, ParamNameLoc, ParamName);
1005 // Add the template parameter into the current scope.
1007 IdResolver.AddDecl(Param);
1010 // C++0x [temp.param]p9:
1011 // A default template-argument may be specified for any kind of
1012 // template-parameter that is not a template parameter pack.
1013 if (DefaultArg && IsParameterPack) {
1014 Diag(EqualLoc, diag::err_template_param_pack_default_arg);
1015 DefaultArg = nullptr;
1018 // Handle the default argument, if provided.
1020 TypeSourceInfo *DefaultTInfo;
1021 GetTypeFromParser(DefaultArg, &DefaultTInfo);
1023 assert(DefaultTInfo && "expected source information for type");
1025 // Check for unexpanded parameter packs.
1026 if (DiagnoseUnexpandedParameterPack(ParamNameLoc, DefaultTInfo,
1027 UPPC_DefaultArgument))
1030 // Check the template argument itself.
1031 if (CheckTemplateArgument(Param, DefaultTInfo)) {
1032 Param->setInvalidDecl();
1036 Param->setDefaultArgument(DefaultTInfo);
1042 /// Convert the parser's template argument list representation into our form.
1043 static TemplateArgumentListInfo
1044 makeTemplateArgumentListInfo(Sema &S, TemplateIdAnnotation &TemplateId) {
1045 TemplateArgumentListInfo TemplateArgs(TemplateId.LAngleLoc,
1046 TemplateId.RAngleLoc);
1047 ASTTemplateArgsPtr TemplateArgsPtr(TemplateId.getTemplateArgs(),
1048 TemplateId.NumArgs);
1049 S.translateTemplateArguments(TemplateArgsPtr, TemplateArgs);
1050 return TemplateArgs;
1053 bool Sema::ActOnTypeConstraint(const CXXScopeSpec &SS,
1054 TemplateIdAnnotation *TypeConstr,
1055 TemplateTypeParmDecl *ConstrainedParameter,
1056 SourceLocation EllipsisLoc) {
1058 cast<ConceptDecl>(TypeConstr->Template.get().getAsTemplateDecl());
1060 // C++2a [temp.param]p4:
1061 // [...] The concept designated by a type-constraint shall be a type
1062 // concept ([temp.concept]).
1063 if (!CD->isTypeConcept()) {
1064 Diag(TypeConstr->TemplateNameLoc,
1065 diag::err_type_constraint_non_type_concept);
1069 bool WereArgsSpecified = TypeConstr->LAngleLoc.isValid();
1071 if (!WereArgsSpecified &&
1072 CD->getTemplateParameters()->getMinRequiredArguments() > 1) {
1073 Diag(TypeConstr->TemplateNameLoc,
1074 diag::err_type_constraint_missing_arguments) << CD;
1078 TemplateArgumentListInfo TemplateArgs;
1079 if (TypeConstr->LAngleLoc.isValid()) {
1081 makeTemplateArgumentListInfo(*this, *TypeConstr);
1083 return AttachTypeConstraint(
1084 SS.isSet() ? SS.getWithLocInContext(Context) : NestedNameSpecifierLoc(),
1085 DeclarationNameInfo(DeclarationName(TypeConstr->Name),
1086 TypeConstr->TemplateNameLoc), CD,
1087 TypeConstr->LAngleLoc.isValid() ? &TemplateArgs : nullptr,
1088 ConstrainedParameter, EllipsisLoc);
1091 template<typename ArgumentLocAppender>
1092 static ExprResult formImmediatelyDeclaredConstraint(
1093 Sema &S, NestedNameSpecifierLoc NS, DeclarationNameInfo NameInfo,
1094 ConceptDecl *NamedConcept, SourceLocation LAngleLoc,
1095 SourceLocation RAngleLoc, QualType ConstrainedType,
1096 SourceLocation ParamNameLoc, ArgumentLocAppender Appender,
1097 SourceLocation EllipsisLoc) {
1099 TemplateArgumentListInfo ConstraintArgs;
1100 ConstraintArgs.addArgument(
1101 S.getTrivialTemplateArgumentLoc(TemplateArgument(ConstrainedType),
1102 /*NTTPType=*/QualType(), ParamNameLoc));
1104 ConstraintArgs.setRAngleLoc(RAngleLoc);
1105 ConstraintArgs.setLAngleLoc(LAngleLoc);
1106 Appender(ConstraintArgs);
1108 // C++2a [temp.param]p4:
1109 // [...] This constraint-expression E is called the immediately-declared
1110 // constraint of T. [...]
1113 ExprResult ImmediatelyDeclaredConstraint = S.CheckConceptTemplateId(
1114 SS, /*TemplateKWLoc=*/SourceLocation(), NameInfo,
1115 /*FoundDecl=*/NamedConcept, NamedConcept, &ConstraintArgs);
1116 if (ImmediatelyDeclaredConstraint.isInvalid() || !EllipsisLoc.isValid())
1117 return ImmediatelyDeclaredConstraint;
1119 // C++2a [temp.param]p4:
1120 // [...] If T is not a pack, then E is E', otherwise E is (E' && ...).
1122 // We have the following case:
1124 // template<typename T> concept C1 = true;
1125 // template<C1... T> struct s1;
1127 // The constraint: (C1<T> && ...)
1128 return S.BuildCXXFoldExpr(/*LParenLoc=*/SourceLocation(),
1129 ImmediatelyDeclaredConstraint.get(), BO_LAnd,
1130 EllipsisLoc, /*RHS=*/nullptr,
1131 /*RParenLoc=*/SourceLocation(),
1132 /*NumExpansions=*/None);
1135 /// Attach a type-constraint to a template parameter.
1136 /// \returns true if an error occured. This can happen if the
1137 /// immediately-declared constraint could not be formed (e.g. incorrect number
1138 /// of arguments for the named concept).
1139 bool Sema::AttachTypeConstraint(NestedNameSpecifierLoc NS,
1140 DeclarationNameInfo NameInfo,
1141 ConceptDecl *NamedConcept,
1142 const TemplateArgumentListInfo *TemplateArgs,
1143 TemplateTypeParmDecl *ConstrainedParameter,
1144 SourceLocation EllipsisLoc) {
1145 // C++2a [temp.param]p4:
1146 // [...] If Q is of the form C<A1, ..., An>, then let E' be
1147 // C<T, A1, ..., An>. Otherwise, let E' be C<T>. [...]
1148 const ASTTemplateArgumentListInfo *ArgsAsWritten =
1149 TemplateArgs ? ASTTemplateArgumentListInfo::Create(Context,
1150 *TemplateArgs) : nullptr;
1152 QualType ParamAsArgument(ConstrainedParameter->getTypeForDecl(), 0);
1154 ExprResult ImmediatelyDeclaredConstraint =
1155 formImmediatelyDeclaredConstraint(
1156 *this, NS, NameInfo, NamedConcept,
1157 TemplateArgs ? TemplateArgs->getLAngleLoc() : SourceLocation(),
1158 TemplateArgs ? TemplateArgs->getRAngleLoc() : SourceLocation(),
1159 ParamAsArgument, ConstrainedParameter->getLocation(),
1160 [&] (TemplateArgumentListInfo &ConstraintArgs) {
1162 for (const auto &ArgLoc : TemplateArgs->arguments())
1163 ConstraintArgs.addArgument(ArgLoc);
1165 if (ImmediatelyDeclaredConstraint.isInvalid())
1168 ConstrainedParameter->setTypeConstraint(NS, NameInfo,
1169 /*FoundDecl=*/NamedConcept,
1170 NamedConcept, ArgsAsWritten,
1171 ImmediatelyDeclaredConstraint.get());
1175 bool Sema::AttachTypeConstraint(AutoTypeLoc TL, NonTypeTemplateParmDecl *NTTP,
1176 SourceLocation EllipsisLoc) {
1177 if (NTTP->getType() != TL.getType() ||
1178 TL.getAutoKeyword() != AutoTypeKeyword::Auto) {
1179 Diag(NTTP->getTypeSourceInfo()->getTypeLoc().getBeginLoc(),
1180 diag::err_unsupported_placeholder_constraint)
1181 << NTTP->getTypeSourceInfo()->getTypeLoc().getSourceRange();
1184 // FIXME: Concepts: This should be the type of the placeholder, but this is
1185 // unclear in the wording right now.
1186 DeclRefExpr *Ref = BuildDeclRefExpr(NTTP, NTTP->getType(), VK_RValue,
1187 NTTP->getLocation());
1190 ExprResult ImmediatelyDeclaredConstraint =
1191 formImmediatelyDeclaredConstraint(
1192 *this, TL.getNestedNameSpecifierLoc(), TL.getConceptNameInfo(),
1193 TL.getNamedConcept(), TL.getLAngleLoc(), TL.getRAngleLoc(),
1194 BuildDecltypeType(Ref, NTTP->getLocation()), NTTP->getLocation(),
1195 [&] (TemplateArgumentListInfo &ConstraintArgs) {
1196 for (unsigned I = 0, C = TL.getNumArgs(); I != C; ++I)
1197 ConstraintArgs.addArgument(TL.getArgLoc(I));
1199 if (ImmediatelyDeclaredConstraint.isInvalid() ||
1200 !ImmediatelyDeclaredConstraint.isUsable())
1203 NTTP->setPlaceholderTypeConstraint(ImmediatelyDeclaredConstraint.get());
1207 /// Check that the type of a non-type template parameter is
1210 /// \returns the (possibly-promoted) parameter type if valid;
1211 /// otherwise, produces a diagnostic and returns a NULL type.
1212 QualType Sema::CheckNonTypeTemplateParameterType(TypeSourceInfo *&TSI,
1213 SourceLocation Loc) {
1214 if (TSI->getType()->isUndeducedType()) {
1215 // C++17 [temp.dep.expr]p3:
1216 // An id-expression is type-dependent if it contains
1217 // - an identifier associated by name lookup with a non-type
1218 // template-parameter declared with a type that contains a
1219 // placeholder type (7.1.7.4),
1220 TSI = SubstAutoTypeSourceInfo(TSI, Context.DependentTy);
1223 return CheckNonTypeTemplateParameterType(TSI->getType(), Loc);
1226 QualType Sema::CheckNonTypeTemplateParameterType(QualType T,
1227 SourceLocation Loc) {
1228 // We don't allow variably-modified types as the type of non-type template
1230 if (T->isVariablyModifiedType()) {
1231 Diag(Loc, diag::err_variably_modified_nontype_template_param)
1236 // C++ [temp.param]p4:
1238 // A non-type template-parameter shall have one of the following
1239 // (optionally cv-qualified) types:
1241 // -- integral or enumeration type,
1242 if (T->isIntegralOrEnumerationType() ||
1243 // -- pointer to object or pointer to function,
1244 T->isPointerType() ||
1245 // -- reference to object or reference to function,
1246 T->isReferenceType() ||
1247 // -- pointer to member,
1248 T->isMemberPointerType() ||
1249 // -- std::nullptr_t.
1250 T->isNullPtrType() ||
1251 // Allow use of auto in template parameter declarations.
1252 T->isUndeducedType()) {
1253 // C++ [temp.param]p5: The top-level cv-qualifiers on the template-parameter
1254 // are ignored when determining its type.
1255 return T.getUnqualifiedType();
1258 // C++ [temp.param]p8:
1260 // A non-type template-parameter of type "array of T" or
1261 // "function returning T" is adjusted to be of type "pointer to
1262 // T" or "pointer to function returning T", respectively.
1263 if (T->isArrayType() || T->isFunctionType())
1264 return Context.getDecayedType(T);
1266 // If T is a dependent type, we can't do the check now, so we
1267 // assume that it is well-formed. Note that stripping off the
1268 // qualifiers here is not really correct if T turns out to be
1269 // an array type, but we'll recompute the type everywhere it's
1270 // used during instantiation, so that should be OK. (Using the
1271 // qualified type is equally wrong.)
1272 if (T->isDependentType())
1273 return T.getUnqualifiedType();
1275 Diag(Loc, diag::err_template_nontype_parm_bad_type)
1281 NamedDecl *Sema::ActOnNonTypeTemplateParameter(Scope *S, Declarator &D,
1284 SourceLocation EqualLoc,
1286 TypeSourceInfo *TInfo = GetTypeForDeclarator(D, S);
1288 // Check that we have valid decl-specifiers specified.
1289 auto CheckValidDeclSpecifiers = [this, &D] {
1292 // template-parameter:
1294 // parameter-declaration
1296 // ... A storage class shall not be specified in a template-parameter
1299 // The typedef specifier [...] shall not be used in the decl-specifier-seq
1300 // of a parameter-declaration
1301 const DeclSpec &DS = D.getDeclSpec();
1302 auto EmitDiag = [this](SourceLocation Loc) {
1303 Diag(Loc, diag::err_invalid_decl_specifier_in_nontype_parm)
1304 << FixItHint::CreateRemoval(Loc);
1306 if (DS.getStorageClassSpec() != DeclSpec::SCS_unspecified)
1307 EmitDiag(DS.getStorageClassSpecLoc());
1309 if (DS.getThreadStorageClassSpec() != TSCS_unspecified)
1310 EmitDiag(DS.getThreadStorageClassSpecLoc());
1313 // The inline specifier can be applied only to the declaration or
1314 // definition of a variable or function.
1316 if (DS.isInlineSpecified())
1317 EmitDiag(DS.getInlineSpecLoc());
1319 // [dcl.constexpr]p1:
1320 // The constexpr specifier shall be applied only to the definition of a
1321 // variable or variable template or the declaration of a function or
1322 // function template.
1324 if (DS.hasConstexprSpecifier())
1325 EmitDiag(DS.getConstexprSpecLoc());
1327 // [dcl.fct.spec]p1:
1328 // Function-specifiers can be used only in function declarations.
1330 if (DS.isVirtualSpecified())
1331 EmitDiag(DS.getVirtualSpecLoc());
1333 if (DS.hasExplicitSpecifier())
1334 EmitDiag(DS.getExplicitSpecLoc());
1336 if (DS.isNoreturnSpecified())
1337 EmitDiag(DS.getNoreturnSpecLoc());
1340 CheckValidDeclSpecifiers();
1342 if (TInfo->getType()->isUndeducedType()) {
1343 Diag(D.getIdentifierLoc(),
1344 diag::warn_cxx14_compat_template_nontype_parm_auto_type)
1345 << QualType(TInfo->getType()->getContainedAutoType(), 0);
1348 assert(S->isTemplateParamScope() &&
1349 "Non-type template parameter not in template parameter scope!");
1350 bool Invalid = false;
1352 QualType T = CheckNonTypeTemplateParameterType(TInfo, D.getIdentifierLoc());
1354 T = Context.IntTy; // Recover with an 'int' type.
1358 CheckFunctionOrTemplateParamDeclarator(S, D);
1360 IdentifierInfo *ParamName = D.getIdentifier();
1361 bool IsParameterPack = D.hasEllipsis();
1362 NonTypeTemplateParmDecl *Param = NonTypeTemplateParmDecl::Create(
1363 Context, Context.getTranslationUnitDecl(), D.getBeginLoc(),
1364 D.getIdentifierLoc(), Depth, Position, ParamName, T, IsParameterPack,
1366 Param->setAccess(AS_public);
1368 if (AutoTypeLoc TL = TInfo->getTypeLoc().getContainedAutoTypeLoc())
1369 if (TL.isConstrained())
1370 if (AttachTypeConstraint(TL, Param, D.getEllipsisLoc()))
1374 Param->setInvalidDecl();
1376 if (Param->isParameterPack())
1377 if (auto *LSI = getEnclosingLambda())
1378 LSI->LocalPacks.push_back(Param);
1381 maybeDiagnoseTemplateParameterShadow(*this, S, D.getIdentifierLoc(),
1384 // Add the template parameter into the current scope.
1386 IdResolver.AddDecl(Param);
1389 // C++0x [temp.param]p9:
1390 // A default template-argument may be specified for any kind of
1391 // template-parameter that is not a template parameter pack.
1392 if (Default && IsParameterPack) {
1393 Diag(EqualLoc, diag::err_template_param_pack_default_arg);
1397 // Check the well-formedness of the default template argument, if provided.
1399 // Check for unexpanded parameter packs.
1400 if (DiagnoseUnexpandedParameterPack(Default, UPPC_DefaultArgument))
1403 TemplateArgument Converted;
1404 ExprResult DefaultRes =
1405 CheckTemplateArgument(Param, Param->getType(), Default, Converted);
1406 if (DefaultRes.isInvalid()) {
1407 Param->setInvalidDecl();
1410 Default = DefaultRes.get();
1412 Param->setDefaultArgument(Default);
1418 /// ActOnTemplateTemplateParameter - Called when a C++ template template
1419 /// parameter (e.g. T in template <template \<typename> class T> class array)
1420 /// has been parsed. S is the current scope.
1421 NamedDecl *Sema::ActOnTemplateTemplateParameter(Scope* S,
1422 SourceLocation TmpLoc,
1423 TemplateParameterList *Params,
1424 SourceLocation EllipsisLoc,
1425 IdentifierInfo *Name,
1426 SourceLocation NameLoc,
1429 SourceLocation EqualLoc,
1430 ParsedTemplateArgument Default) {
1431 assert(S->isTemplateParamScope() &&
1432 "Template template parameter not in template parameter scope!");
1434 // Construct the parameter object.
1435 bool IsParameterPack = EllipsisLoc.isValid();
1436 TemplateTemplateParmDecl *Param =
1437 TemplateTemplateParmDecl::Create(Context, Context.getTranslationUnitDecl(),
1438 NameLoc.isInvalid()? TmpLoc : NameLoc,
1439 Depth, Position, IsParameterPack,
1441 Param->setAccess(AS_public);
1443 if (Param->isParameterPack())
1444 if (auto *LSI = getEnclosingLambda())
1445 LSI->LocalPacks.push_back(Param);
1447 // If the template template parameter has a name, then link the identifier
1448 // into the scope and lookup mechanisms.
1450 maybeDiagnoseTemplateParameterShadow(*this, S, NameLoc, Name);
1453 IdResolver.AddDecl(Param);
1456 if (Params->size() == 0) {
1457 Diag(Param->getLocation(), diag::err_template_template_parm_no_parms)
1458 << SourceRange(Params->getLAngleLoc(), Params->getRAngleLoc());
1459 Param->setInvalidDecl();
1462 // C++0x [temp.param]p9:
1463 // A default template-argument may be specified for any kind of
1464 // template-parameter that is not a template parameter pack.
1465 if (IsParameterPack && !Default.isInvalid()) {
1466 Diag(EqualLoc, diag::err_template_param_pack_default_arg);
1467 Default = ParsedTemplateArgument();
1470 if (!Default.isInvalid()) {
1471 // Check only that we have a template template argument. We don't want to
1472 // try to check well-formedness now, because our template template parameter
1473 // might have dependent types in its template parameters, which we wouldn't
1474 // be able to match now.
1476 // If none of the template template parameter's template arguments mention
1477 // other template parameters, we could actually perform more checking here.
1478 // However, it isn't worth doing.
1479 TemplateArgumentLoc DefaultArg = translateTemplateArgument(*this, Default);
1480 if (DefaultArg.getArgument().getAsTemplate().isNull()) {
1481 Diag(DefaultArg.getLocation(), diag::err_template_arg_not_valid_template)
1482 << DefaultArg.getSourceRange();
1486 // Check for unexpanded parameter packs.
1487 if (DiagnoseUnexpandedParameterPack(DefaultArg.getLocation(),
1488 DefaultArg.getArgument().getAsTemplate(),
1489 UPPC_DefaultArgument))
1492 Param->setDefaultArgument(Context, DefaultArg);
1498 /// ActOnTemplateParameterList - Builds a TemplateParameterList, optionally
1499 /// constrained by RequiresClause, that contains the template parameters in
1501 TemplateParameterList *
1502 Sema::ActOnTemplateParameterList(unsigned Depth,
1503 SourceLocation ExportLoc,
1504 SourceLocation TemplateLoc,
1505 SourceLocation LAngleLoc,
1506 ArrayRef<NamedDecl *> Params,
1507 SourceLocation RAngleLoc,
1508 Expr *RequiresClause) {
1509 if (ExportLoc.isValid())
1510 Diag(ExportLoc, diag::warn_template_export_unsupported);
1512 return TemplateParameterList::Create(
1513 Context, TemplateLoc, LAngleLoc,
1514 llvm::makeArrayRef(Params.data(), Params.size()),
1515 RAngleLoc, RequiresClause);
1518 static void SetNestedNameSpecifier(Sema &S, TagDecl *T,
1519 const CXXScopeSpec &SS) {
1521 T->setQualifierInfo(SS.getWithLocInContext(S.Context));
1524 DeclResult Sema::CheckClassTemplate(
1525 Scope *S, unsigned TagSpec, TagUseKind TUK, SourceLocation KWLoc,
1526 CXXScopeSpec &SS, IdentifierInfo *Name, SourceLocation NameLoc,
1527 const ParsedAttributesView &Attr, TemplateParameterList *TemplateParams,
1528 AccessSpecifier AS, SourceLocation ModulePrivateLoc,
1529 SourceLocation FriendLoc, unsigned NumOuterTemplateParamLists,
1530 TemplateParameterList **OuterTemplateParamLists, SkipBodyInfo *SkipBody) {
1531 assert(TemplateParams && TemplateParams->size() > 0 &&
1532 "No template parameters");
1533 assert(TUK != TUK_Reference && "Can only declare or define class templates");
1534 bool Invalid = false;
1536 // Check that we can declare a template here.
1537 if (CheckTemplateDeclScope(S, TemplateParams))
1540 TagTypeKind Kind = TypeWithKeyword::getTagTypeKindForTypeSpec(TagSpec);
1541 assert(Kind != TTK_Enum && "can't build template of enumerated type");
1543 // There is no such thing as an unnamed class template.
1545 Diag(KWLoc, diag::err_template_unnamed_class);
1549 // Find any previous declaration with this name. For a friend with no
1550 // scope explicitly specified, we only look for tag declarations (per
1551 // C++11 [basic.lookup.elab]p2).
1552 DeclContext *SemanticContext;
1553 LookupResult Previous(*this, Name, NameLoc,
1554 (SS.isEmpty() && TUK == TUK_Friend)
1555 ? LookupTagName : LookupOrdinaryName,
1556 forRedeclarationInCurContext());
1557 if (SS.isNotEmpty() && !SS.isInvalid()) {
1558 SemanticContext = computeDeclContext(SS, true);
1559 if (!SemanticContext) {
1560 // FIXME: Horrible, horrible hack! We can't currently represent this
1561 // in the AST, and historically we have just ignored such friend
1562 // class templates, so don't complain here.
1563 Diag(NameLoc, TUK == TUK_Friend
1564 ? diag::warn_template_qualified_friend_ignored
1565 : diag::err_template_qualified_declarator_no_match)
1566 << SS.getScopeRep() << SS.getRange();
1567 return TUK != TUK_Friend;
1570 if (RequireCompleteDeclContext(SS, SemanticContext))
1573 // If we're adding a template to a dependent context, we may need to
1574 // rebuilding some of the types used within the template parameter list,
1575 // now that we know what the current instantiation is.
1576 if (SemanticContext->isDependentContext()) {
1577 ContextRAII SavedContext(*this, SemanticContext);
1578 if (RebuildTemplateParamsInCurrentInstantiation(TemplateParams))
1580 } else if (TUK != TUK_Friend && TUK != TUK_Reference)
1581 diagnoseQualifiedDeclaration(SS, SemanticContext, Name, NameLoc, false);
1583 LookupQualifiedName(Previous, SemanticContext);
1585 SemanticContext = CurContext;
1587 // C++14 [class.mem]p14:
1588 // If T is the name of a class, then each of the following shall have a
1589 // name different from T:
1590 // -- every member template of class T
1591 if (TUK != TUK_Friend &&
1592 DiagnoseClassNameShadow(SemanticContext,
1593 DeclarationNameInfo(Name, NameLoc)))
1596 LookupName(Previous, S);
1599 if (Previous.isAmbiguous())
1602 NamedDecl *PrevDecl = nullptr;
1603 if (Previous.begin() != Previous.end())
1604 PrevDecl = (*Previous.begin())->getUnderlyingDecl();
1606 if (PrevDecl && PrevDecl->isTemplateParameter()) {
1607 // Maybe we will complain about the shadowed template parameter.
1608 DiagnoseTemplateParameterShadow(NameLoc, PrevDecl);
1609 // Just pretend that we didn't see the previous declaration.
1613 // If there is a previous declaration with the same name, check
1614 // whether this is a valid redeclaration.
1615 ClassTemplateDecl *PrevClassTemplate =
1616 dyn_cast_or_null<ClassTemplateDecl>(PrevDecl);
1618 // We may have found the injected-class-name of a class template,
1619 // class template partial specialization, or class template specialization.
1620 // In these cases, grab the template that is being defined or specialized.
1621 if (!PrevClassTemplate && PrevDecl && isa<CXXRecordDecl>(PrevDecl) &&
1622 cast<CXXRecordDecl>(PrevDecl)->isInjectedClassName()) {
1623 PrevDecl = cast<CXXRecordDecl>(PrevDecl->getDeclContext());
1625 = cast<CXXRecordDecl>(PrevDecl)->getDescribedClassTemplate();
1626 if (!PrevClassTemplate && isa<ClassTemplateSpecializationDecl>(PrevDecl)) {
1628 = cast<ClassTemplateSpecializationDecl>(PrevDecl)
1629 ->getSpecializedTemplate();
1633 if (TUK == TUK_Friend) {
1634 // C++ [namespace.memdef]p3:
1635 // [...] When looking for a prior declaration of a class or a function
1636 // declared as a friend, and when the name of the friend class or
1637 // function is neither a qualified name nor a template-id, scopes outside
1638 // the innermost enclosing namespace scope are not considered.
1640 DeclContext *OutermostContext = CurContext;
1641 while (!OutermostContext->isFileContext())
1642 OutermostContext = OutermostContext->getLookupParent();
1645 (OutermostContext->Equals(PrevDecl->getDeclContext()) ||
1646 OutermostContext->Encloses(PrevDecl->getDeclContext()))) {
1647 SemanticContext = PrevDecl->getDeclContext();
1649 // Declarations in outer scopes don't matter. However, the outermost
1650 // context we computed is the semantic context for our new
1652 PrevDecl = PrevClassTemplate = nullptr;
1653 SemanticContext = OutermostContext;
1655 // Check that the chosen semantic context doesn't already contain a
1656 // declaration of this name as a non-tag type.
1657 Previous.clear(LookupOrdinaryName);
1658 DeclContext *LookupContext = SemanticContext;
1659 while (LookupContext->isTransparentContext())
1660 LookupContext = LookupContext->getLookupParent();
1661 LookupQualifiedName(Previous, LookupContext);
1663 if (Previous.isAmbiguous())
1666 if (Previous.begin() != Previous.end())
1667 PrevDecl = (*Previous.begin())->getUnderlyingDecl();
1670 } else if (PrevDecl &&
1671 !isDeclInScope(Previous.getRepresentativeDecl(), SemanticContext,
1673 PrevDecl = PrevClassTemplate = nullptr;
1675 if (auto *Shadow = dyn_cast_or_null<UsingShadowDecl>(
1676 PrevDecl ? Previous.getRepresentativeDecl() : nullptr)) {
1678 !(PrevClassTemplate &&
1679 PrevClassTemplate->getDeclContext()->getRedeclContext()->Equals(
1680 SemanticContext->getRedeclContext()))) {
1681 Diag(KWLoc, diag::err_using_decl_conflict_reverse);
1682 Diag(Shadow->getTargetDecl()->getLocation(),
1683 diag::note_using_decl_target);
1684 Diag(Shadow->getUsingDecl()->getLocation(), diag::note_using_decl) << 0;
1685 // Recover by ignoring the old declaration.
1686 PrevDecl = PrevClassTemplate = nullptr;
1690 if (PrevClassTemplate) {
1691 // Ensure that the template parameter lists are compatible. Skip this check
1692 // for a friend in a dependent context: the template parameter list itself
1693 // could be dependent.
1694 if (!(TUK == TUK_Friend && CurContext->isDependentContext()) &&
1695 !TemplateParameterListsAreEqual(TemplateParams,
1696 PrevClassTemplate->getTemplateParameters(),
1701 // C++ [temp.class]p4:
1702 // In a redeclaration, partial specialization, explicit
1703 // specialization or explicit instantiation of a class template,
1704 // the class-key shall agree in kind with the original class
1705 // template declaration (7.1.5.3).
1706 RecordDecl *PrevRecordDecl = PrevClassTemplate->getTemplatedDecl();
1707 if (!isAcceptableTagRedeclaration(PrevRecordDecl, Kind,
1708 TUK == TUK_Definition, KWLoc, Name)) {
1709 Diag(KWLoc, diag::err_use_with_wrong_tag)
1711 << FixItHint::CreateReplacement(KWLoc, PrevRecordDecl->getKindName());
1712 Diag(PrevRecordDecl->getLocation(), diag::note_previous_use);
1713 Kind = PrevRecordDecl->getTagKind();
1716 // Check for redefinition of this class template.
1717 if (TUK == TUK_Definition) {
1718 if (TagDecl *Def = PrevRecordDecl->getDefinition()) {
1719 // If we have a prior definition that is not visible, treat this as
1720 // simply making that previous definition visible.
1721 NamedDecl *Hidden = nullptr;
1722 if (SkipBody && !hasVisibleDefinition(Def, &Hidden)) {
1723 SkipBody->ShouldSkip = true;
1724 SkipBody->Previous = Def;
1725 auto *Tmpl = cast<CXXRecordDecl>(Hidden)->getDescribedClassTemplate();
1726 assert(Tmpl && "original definition of a class template is not a "
1728 makeMergedDefinitionVisible(Hidden);
1729 makeMergedDefinitionVisible(Tmpl);
1731 Diag(NameLoc, diag::err_redefinition) << Name;
1732 Diag(Def->getLocation(), diag::note_previous_definition);
1733 // FIXME: Would it make sense to try to "forget" the previous
1734 // definition, as part of error recovery?
1739 } else if (PrevDecl) {
1741 // A class template shall not have the same name as any other
1742 // template, class, function, object, enumeration, enumerator,
1743 // namespace, or type in the same scope (3.3), except as specified
1745 Diag(NameLoc, diag::err_redefinition_different_kind) << Name;
1746 Diag(PrevDecl->getLocation(), diag::note_previous_definition);
1750 // Check the template parameter list of this declaration, possibly
1751 // merging in the template parameter list from the previous class
1752 // template declaration. Skip this check for a friend in a dependent
1753 // context, because the template parameter list might be dependent.
1754 if (!(TUK == TUK_Friend && CurContext->isDependentContext()) &&
1755 CheckTemplateParameterList(
1758 ? PrevClassTemplate->getMostRecentDecl()->getTemplateParameters()
1760 (SS.isSet() && SemanticContext && SemanticContext->isRecord() &&
1761 SemanticContext->isDependentContext())
1762 ? TPC_ClassTemplateMember
1763 : TUK == TUK_Friend ? TPC_FriendClassTemplate : TPC_ClassTemplate,
1768 // If the name of the template was qualified, we must be defining the
1769 // template out-of-line.
1770 if (!SS.isInvalid() && !Invalid && !PrevClassTemplate) {
1771 Diag(NameLoc, TUK == TUK_Friend ? diag::err_friend_decl_does_not_match
1772 : diag::err_member_decl_does_not_match)
1773 << Name << SemanticContext << /*IsDefinition*/true << SS.getRange();
1778 // If this is a templated friend in a dependent context we should not put it
1779 // on the redecl chain. In some cases, the templated friend can be the most
1780 // recent declaration tricking the template instantiator to make substitutions
1782 // FIXME: Figure out how to combine with shouldLinkDependentDeclWithPrevious
1783 bool ShouldAddRedecl
1784 = !(TUK == TUK_Friend && CurContext->isDependentContext());
1786 CXXRecordDecl *NewClass =
1787 CXXRecordDecl::Create(Context, Kind, SemanticContext, KWLoc, NameLoc, Name,
1788 PrevClassTemplate && ShouldAddRedecl ?
1789 PrevClassTemplate->getTemplatedDecl() : nullptr,
1790 /*DelayTypeCreation=*/true);
1791 SetNestedNameSpecifier(*this, NewClass, SS);
1792 if (NumOuterTemplateParamLists > 0)
1793 NewClass->setTemplateParameterListsInfo(
1794 Context, llvm::makeArrayRef(OuterTemplateParamLists,
1795 NumOuterTemplateParamLists));
1797 // Add alignment attributes if necessary; these attributes are checked when
1798 // the ASTContext lays out the structure.
1799 if (TUK == TUK_Definition && (!SkipBody || !SkipBody->ShouldSkip)) {
1800 AddAlignmentAttributesForRecord(NewClass);
1801 AddMsStructLayoutForRecord(NewClass);
1804 ClassTemplateDecl *NewTemplate
1805 = ClassTemplateDecl::Create(Context, SemanticContext, NameLoc,
1806 DeclarationName(Name), TemplateParams,
1809 if (ShouldAddRedecl)
1810 NewTemplate->setPreviousDecl(PrevClassTemplate);
1812 NewClass->setDescribedClassTemplate(NewTemplate);
1814 if (ModulePrivateLoc.isValid())
1815 NewTemplate->setModulePrivate();
1817 // Build the type for the class template declaration now.
1818 QualType T = NewTemplate->getInjectedClassNameSpecialization();
1819 T = Context.getInjectedClassNameType(NewClass, T);
1820 assert(T->isDependentType() && "Class template type is not dependent?");
1823 // If we are providing an explicit specialization of a member that is a
1824 // class template, make a note of that.
1825 if (PrevClassTemplate &&
1826 PrevClassTemplate->getInstantiatedFromMemberTemplate())
1827 PrevClassTemplate->setMemberSpecialization();
1829 // Set the access specifier.
1830 if (!Invalid && TUK != TUK_Friend && NewTemplate->getDeclContext()->isRecord())
1831 SetMemberAccessSpecifier(NewTemplate, PrevClassTemplate, AS);
1833 // Set the lexical context of these templates
1834 NewClass->setLexicalDeclContext(CurContext);
1835 NewTemplate->setLexicalDeclContext(CurContext);
1837 if (TUK == TUK_Definition && (!SkipBody || !SkipBody->ShouldSkip))
1838 NewClass->startDefinition();
1840 ProcessDeclAttributeList(S, NewClass, Attr);
1842 if (PrevClassTemplate)
1843 mergeDeclAttributes(NewClass, PrevClassTemplate->getTemplatedDecl());
1845 AddPushedVisibilityAttribute(NewClass);
1846 inferGslOwnerPointerAttribute(NewClass);
1848 if (TUK != TUK_Friend) {
1849 // Per C++ [basic.scope.temp]p2, skip the template parameter scopes.
1851 while ((Outer->getFlags() & Scope::TemplateParamScope) != 0)
1852 Outer = Outer->getParent();
1853 PushOnScopeChains(NewTemplate, Outer);
1855 if (PrevClassTemplate && PrevClassTemplate->getAccess() != AS_none) {
1856 NewTemplate->setAccess(PrevClassTemplate->getAccess());
1857 NewClass->setAccess(PrevClassTemplate->getAccess());
1860 NewTemplate->setObjectOfFriendDecl();
1862 // Friend templates are visible in fairly strange ways.
1863 if (!CurContext->isDependentContext()) {
1864 DeclContext *DC = SemanticContext->getRedeclContext();
1865 DC->makeDeclVisibleInContext(NewTemplate);
1866 if (Scope *EnclosingScope = getScopeForDeclContext(S, DC))
1867 PushOnScopeChains(NewTemplate, EnclosingScope,
1868 /* AddToContext = */ false);
1871 FriendDecl *Friend = FriendDecl::Create(
1872 Context, CurContext, NewClass->getLocation(), NewTemplate, FriendLoc);
1873 Friend->setAccess(AS_public);
1874 CurContext->addDecl(Friend);
1877 if (PrevClassTemplate)
1878 CheckRedeclarationModuleOwnership(NewTemplate, PrevClassTemplate);
1881 NewTemplate->setInvalidDecl();
1882 NewClass->setInvalidDecl();
1885 ActOnDocumentableDecl(NewTemplate);
1887 if (SkipBody && SkipBody->ShouldSkip)
1888 return SkipBody->Previous;
1894 /// Tree transform to "extract" a transformed type from a class template's
1895 /// constructor to a deduction guide.
1896 class ExtractTypeForDeductionGuide
1897 : public TreeTransform<ExtractTypeForDeductionGuide> {
1899 typedef TreeTransform<ExtractTypeForDeductionGuide> Base;
1900 ExtractTypeForDeductionGuide(Sema &SemaRef) : Base(SemaRef) {}
1902 TypeSourceInfo *transform(TypeSourceInfo *TSI) { return TransformType(TSI); }
1904 QualType TransformTypedefType(TypeLocBuilder &TLB, TypedefTypeLoc TL) {
1905 return TransformType(
1907 TL.getTypedefNameDecl()->getTypeSourceInfo()->getTypeLoc());
1911 /// Transform to convert portions of a constructor declaration into the
1912 /// corresponding deduction guide, per C++1z [over.match.class.deduct]p1.
1913 struct ConvertConstructorToDeductionGuideTransform {
1914 ConvertConstructorToDeductionGuideTransform(Sema &S,
1915 ClassTemplateDecl *Template)
1916 : SemaRef(S), Template(Template) {}
1919 ClassTemplateDecl *Template;
1921 DeclContext *DC = Template->getDeclContext();
1922 CXXRecordDecl *Primary = Template->getTemplatedDecl();
1923 DeclarationName DeductionGuideName =
1924 SemaRef.Context.DeclarationNames.getCXXDeductionGuideName(Template);
1926 QualType DeducedType = SemaRef.Context.getTypeDeclType(Primary);
1928 // Index adjustment to apply to convert depth-1 template parameters into
1929 // depth-0 template parameters.
1930 unsigned Depth1IndexAdjustment = Template->getTemplateParameters()->size();
1932 /// Transform a constructor declaration into a deduction guide.
1933 NamedDecl *transformConstructor(FunctionTemplateDecl *FTD,
1934 CXXConstructorDecl *CD) {
1935 SmallVector<TemplateArgument, 16> SubstArgs;
1937 LocalInstantiationScope Scope(SemaRef);
1939 // C++ [over.match.class.deduct]p1:
1940 // -- For each constructor of the class template designated by the
1941 // template-name, a function template with the following properties:
1943 // -- The template parameters are the template parameters of the class
1944 // template followed by the template parameters (including default
1945 // template arguments) of the constructor, if any.
1946 TemplateParameterList *TemplateParams = Template->getTemplateParameters();
1948 TemplateParameterList *InnerParams = FTD->getTemplateParameters();
1949 SmallVector<NamedDecl *, 16> AllParams;
1950 AllParams.reserve(TemplateParams->size() + InnerParams->size());
1951 AllParams.insert(AllParams.begin(),
1952 TemplateParams->begin(), TemplateParams->end());
1953 SubstArgs.reserve(InnerParams->size());
1955 // Later template parameters could refer to earlier ones, so build up
1956 // a list of substituted template arguments as we go.
1957 for (NamedDecl *Param : *InnerParams) {
1958 MultiLevelTemplateArgumentList Args;
1959 Args.addOuterTemplateArguments(SubstArgs);
1960 Args.addOuterRetainedLevel();
1961 NamedDecl *NewParam = transformTemplateParameter(Param, Args);
1964 AllParams.push_back(NewParam);
1965 SubstArgs.push_back(SemaRef.Context.getCanonicalTemplateArgument(
1966 SemaRef.Context.getInjectedTemplateArg(NewParam)));
1968 TemplateParams = TemplateParameterList::Create(
1969 SemaRef.Context, InnerParams->getTemplateLoc(),
1970 InnerParams->getLAngleLoc(), AllParams, InnerParams->getRAngleLoc(),
1971 /*FIXME: RequiresClause*/ nullptr);
1974 // If we built a new template-parameter-list, track that we need to
1975 // substitute references to the old parameters into references to the
1977 MultiLevelTemplateArgumentList Args;
1979 Args.addOuterTemplateArguments(SubstArgs);
1980 Args.addOuterRetainedLevel();
1983 FunctionProtoTypeLoc FPTL = CD->getTypeSourceInfo()->getTypeLoc()
1984 .getAsAdjusted<FunctionProtoTypeLoc>();
1985 assert(FPTL && "no prototype for constructor declaration");
1987 // Transform the type of the function, adjusting the return type and
1988 // replacing references to the old parameters with references to the
1991 SmallVector<ParmVarDecl*, 8> Params;
1992 QualType NewType = transformFunctionProtoType(TLB, FPTL, Params, Args);
1993 if (NewType.isNull())
1995 TypeSourceInfo *NewTInfo = TLB.getTypeSourceInfo(SemaRef.Context, NewType);
1997 return buildDeductionGuide(TemplateParams, CD->getExplicitSpecifier(),
1998 NewTInfo, CD->getBeginLoc(), CD->getLocation(),
2002 /// Build a deduction guide with the specified parameter types.
2003 NamedDecl *buildSimpleDeductionGuide(MutableArrayRef<QualType> ParamTypes) {
2004 SourceLocation Loc = Template->getLocation();
2006 // Build the requested type.
2007 FunctionProtoType::ExtProtoInfo EPI;
2008 EPI.HasTrailingReturn = true;
2009 QualType Result = SemaRef.BuildFunctionType(DeducedType, ParamTypes, Loc,
2010 DeductionGuideName, EPI);
2011 TypeSourceInfo *TSI = SemaRef.Context.getTrivialTypeSourceInfo(Result, Loc);
2013 FunctionProtoTypeLoc FPTL =
2014 TSI->getTypeLoc().castAs<FunctionProtoTypeLoc>();
2016 // Build the parameters, needed during deduction / substitution.
2017 SmallVector<ParmVarDecl*, 4> Params;
2018 for (auto T : ParamTypes) {
2019 ParmVarDecl *NewParam = ParmVarDecl::Create(
2020 SemaRef.Context, DC, Loc, Loc, nullptr, T,
2021 SemaRef.Context.getTrivialTypeSourceInfo(T, Loc), SC_None, nullptr);
2022 NewParam->setScopeInfo(0, Params.size());
2023 FPTL.setParam(Params.size(), NewParam);
2024 Params.push_back(NewParam);
2027 return buildDeductionGuide(Template->getTemplateParameters(),
2028 ExplicitSpecifier(), TSI, Loc, Loc, Loc);
2032 /// Transform a constructor template parameter into a deduction guide template
2033 /// parameter, rebuilding any internal references to earlier parameters and
2034 /// renumbering as we go.
2035 NamedDecl *transformTemplateParameter(NamedDecl *TemplateParam,
2036 MultiLevelTemplateArgumentList &Args) {
2037 if (auto *TTP = dyn_cast<TemplateTypeParmDecl>(TemplateParam)) {
2038 // TemplateTypeParmDecl's index cannot be changed after creation, so
2039 // substitute it directly.
2040 auto *NewTTP = TemplateTypeParmDecl::Create(
2041 SemaRef.Context, DC, TTP->getBeginLoc(), TTP->getLocation(),
2042 /*Depth*/ 0, Depth1IndexAdjustment + TTP->getIndex(),
2043 TTP->getIdentifier(), TTP->wasDeclaredWithTypename(),
2044 TTP->isParameterPack(), TTP->hasTypeConstraint(),
2045 TTP->isExpandedParameterPack() ?
2046 llvm::Optional<unsigned>(TTP->getNumExpansionParameters()) : None);
2047 if (const auto *TC = TTP->getTypeConstraint()) {
2048 TemplateArgumentListInfo TransformedArgs;
2049 const auto *ArgsAsWritten = TC->getTemplateArgsAsWritten();
2050 if (!ArgsAsWritten ||
2051 SemaRef.Subst(ArgsAsWritten->getTemplateArgs(),
2052 ArgsAsWritten->NumTemplateArgs, TransformedArgs,
2054 SemaRef.AttachTypeConstraint(
2055 TC->getNestedNameSpecifierLoc(), TC->getConceptNameInfo(),
2056 TC->getNamedConcept(), ArgsAsWritten ? &TransformedArgs : nullptr,
2058 NewTTP->isParameterPack()
2059 ? cast<CXXFoldExpr>(TC->getImmediatelyDeclaredConstraint())
2061 : SourceLocation());
2063 if (TTP->hasDefaultArgument()) {
2064 TypeSourceInfo *InstantiatedDefaultArg =
2065 SemaRef.SubstType(TTP->getDefaultArgumentInfo(), Args,
2066 TTP->getDefaultArgumentLoc(), TTP->getDeclName());
2067 if (InstantiatedDefaultArg)
2068 NewTTP->setDefaultArgument(InstantiatedDefaultArg);
2070 SemaRef.CurrentInstantiationScope->InstantiatedLocal(TemplateParam,
2075 if (auto *TTP = dyn_cast<TemplateTemplateParmDecl>(TemplateParam))
2076 return transformTemplateParameterImpl(TTP, Args);
2078 return transformTemplateParameterImpl(
2079 cast<NonTypeTemplateParmDecl>(TemplateParam), Args);
2081 template<typename TemplateParmDecl>
2083 transformTemplateParameterImpl(TemplateParmDecl *OldParam,
2084 MultiLevelTemplateArgumentList &Args) {
2085 // Ask the template instantiator to do the heavy lifting for us, then adjust
2086 // the index of the parameter once it's done.
2088 cast<TemplateParmDecl>(SemaRef.SubstDecl(OldParam, DC, Args));
2089 assert(NewParam->getDepth() == 0 && "unexpected template param depth");
2090 NewParam->setPosition(NewParam->getPosition() + Depth1IndexAdjustment);
2094 QualType transformFunctionProtoType(TypeLocBuilder &TLB,
2095 FunctionProtoTypeLoc TL,
2096 SmallVectorImpl<ParmVarDecl*> &Params,
2097 MultiLevelTemplateArgumentList &Args) {
2098 SmallVector<QualType, 4> ParamTypes;
2099 const FunctionProtoType *T = TL.getTypePtr();
2101 // -- The types of the function parameters are those of the constructor.
2102 for (auto *OldParam : TL.getParams()) {
2103 ParmVarDecl *NewParam = transformFunctionTypeParam(OldParam, Args);
2106 ParamTypes.push_back(NewParam->getType());
2107 Params.push_back(NewParam);
2110 // -- The return type is the class template specialization designated by
2111 // the template-name and template arguments corresponding to the
2112 // template parameters obtained from the class template.
2114 // We use the injected-class-name type of the primary template instead.
2115 // This has the convenient property that it is different from any type that
2116 // the user can write in a deduction-guide (because they cannot enter the
2117 // context of the template), so implicit deduction guides can never collide
2118 // with explicit ones.
2119 QualType ReturnType = DeducedType;
2120 TLB.pushTypeSpec(ReturnType).setNameLoc(Primary->getLocation());
2122 // Resolving a wording defect, we also inherit the variadicness of the
2124 FunctionProtoType::ExtProtoInfo EPI;
2125 EPI.Variadic = T->isVariadic();
2126 EPI.HasTrailingReturn = true;
2128 QualType Result = SemaRef.BuildFunctionType(
2129 ReturnType, ParamTypes, TL.getBeginLoc(), DeductionGuideName, EPI);
2130 if (Result.isNull())
2133 FunctionProtoTypeLoc NewTL = TLB.push<FunctionProtoTypeLoc>(Result);
2134 NewTL.setLocalRangeBegin(TL.getLocalRangeBegin());
2135 NewTL.setLParenLoc(TL.getLParenLoc());
2136 NewTL.setRParenLoc(TL.getRParenLoc());
2137 NewTL.setExceptionSpecRange(SourceRange());
2138 NewTL.setLocalRangeEnd(TL.getLocalRangeEnd());
2139 for (unsigned I = 0, E = NewTL.getNumParams(); I != E; ++I)
2140 NewTL.setParam(I, Params[I]);
2146 transformFunctionTypeParam(ParmVarDecl *OldParam,
2147 MultiLevelTemplateArgumentList &Args) {
2148 TypeSourceInfo *OldDI = OldParam->getTypeSourceInfo();
2149 TypeSourceInfo *NewDI;
2150 if (auto PackTL = OldDI->getTypeLoc().getAs<PackExpansionTypeLoc>()) {
2151 // Expand out the one and only element in each inner pack.
2152 Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, 0);
2154 SemaRef.SubstType(PackTL.getPatternLoc(), Args,
2155 OldParam->getLocation(), OldParam->getDeclName());
2156 if (!NewDI) return nullptr;
2158 SemaRef.CheckPackExpansion(NewDI, PackTL.getEllipsisLoc(),
2159 PackTL.getTypePtr()->getNumExpansions());
2161 NewDI = SemaRef.SubstType(OldDI, Args, OldParam->getLocation(),
2162 OldParam->getDeclName());
2166 // Extract the type. This (for instance) replaces references to typedef
2167 // members of the current instantiations with the definitions of those
2168 // typedefs, avoiding triggering instantiation of the deduced type during
2170 NewDI = ExtractTypeForDeductionGuide(SemaRef).transform(NewDI);
2172 // Resolving a wording defect, we also inherit default arguments from the
2174 ExprResult NewDefArg;
2175 if (OldParam->hasDefaultArg()) {
2176 NewDefArg = SemaRef.SubstExpr(OldParam->getDefaultArg(), Args);
2177 if (NewDefArg.isInvalid())
2181 ParmVarDecl *NewParam = ParmVarDecl::Create(SemaRef.Context, DC,
2182 OldParam->getInnerLocStart(),
2183 OldParam->getLocation(),
2184 OldParam->getIdentifier(),
2187 OldParam->getStorageClass(),
2189 NewParam->setScopeInfo(OldParam->getFunctionScopeDepth(),
2190 OldParam->getFunctionScopeIndex());
2191 SemaRef.CurrentInstantiationScope->InstantiatedLocal(OldParam, NewParam);
2195 NamedDecl *buildDeductionGuide(TemplateParameterList *TemplateParams,
2196 ExplicitSpecifier ES, TypeSourceInfo *TInfo,
2197 SourceLocation LocStart, SourceLocation Loc,
2198 SourceLocation LocEnd) {
2199 DeclarationNameInfo Name(DeductionGuideName, Loc);
2200 ArrayRef<ParmVarDecl *> Params =
2201 TInfo->getTypeLoc().castAs<FunctionProtoTypeLoc>().getParams();
2203 // Build the implicit deduction guide template.
2205 CXXDeductionGuideDecl::Create(SemaRef.Context, DC, LocStart, ES, Name,
2206 TInfo->getType(), TInfo, LocEnd);
2207 Guide->setImplicit();
2208 Guide->setParams(Params);
2210 for (auto *Param : Params)
2211 Param->setDeclContext(Guide);
2213 auto *GuideTemplate = FunctionTemplateDecl::Create(
2214 SemaRef.Context, DC, Loc, DeductionGuideName, TemplateParams, Guide);
2215 GuideTemplate->setImplicit();
2216 Guide->setDescribedFunctionTemplate(GuideTemplate);
2218 if (isa<CXXRecordDecl>(DC)) {
2219 Guide->setAccess(AS_public);
2220 GuideTemplate->setAccess(AS_public);
2223 DC->addDecl(GuideTemplate);
2224 return GuideTemplate;
2229 void Sema::DeclareImplicitDeductionGuides(TemplateDecl *Template,
2230 SourceLocation Loc) {
2231 if (CXXRecordDecl *DefRecord =
2232 cast<CXXRecordDecl>(Template->getTemplatedDecl())->getDefinition()) {
2233 TemplateDecl *DescribedTemplate = DefRecord->getDescribedClassTemplate();
2234 Template = DescribedTemplate ? DescribedTemplate : Template;
2237 DeclContext *DC = Template->getDeclContext();
2238 if (DC->isDependentContext())
2241 ConvertConstructorToDeductionGuideTransform Transform(
2242 *this, cast<ClassTemplateDecl>(Template));
2243 if (!isCompleteType(Loc, Transform.DeducedType))
2246 // Check whether we've already declared deduction guides for this template.
2247 // FIXME: Consider storing a flag on the template to indicate this.
2248 auto Existing = DC->lookup(Transform.DeductionGuideName);
2249 for (auto *D : Existing)
2250 if (D->isImplicit())
2253 // In case we were expanding a pack when we attempted to declare deduction
2254 // guides, turn off pack expansion for everything we're about to do.
2255 ArgumentPackSubstitutionIndexRAII SubstIndex(*this, -1);
2256 // Create a template instantiation record to track the "instantiation" of
2257 // constructors into deduction guides.
2258 // FIXME: Add a kind for this to give more meaningful diagnostics. But can
2259 // this substitution process actually fail?
2260 InstantiatingTemplate BuildingDeductionGuides(*this, Loc, Template);
2261 if (BuildingDeductionGuides.isInvalid())
2264 // Convert declared constructors into deduction guide templates.
2265 // FIXME: Skip constructors for which deduction must necessarily fail (those
2266 // for which some class template parameter without a default argument never
2267 // appears in a deduced context).
2268 bool AddedAny = false;
2269 for (NamedDecl *D : LookupConstructors(Transform.Primary)) {
2270 D = D->getUnderlyingDecl();
2271 if (D->isInvalidDecl() || D->isImplicit())
2273 D = cast<NamedDecl>(D->getCanonicalDecl());
2275 auto *FTD = dyn_cast<FunctionTemplateDecl>(D);
2277 dyn_cast_or_null<CXXConstructorDecl>(FTD ? FTD->getTemplatedDecl() : D);
2278 // Class-scope explicit specializations (MS extension) do not result in
2279 // deduction guides.
2280 if (!CD || (!FTD && CD->isFunctionTemplateSpecialization()))
2283 Transform.transformConstructor(FTD, CD);
2287 // C++17 [over.match.class.deduct]
2288 // -- If C is not defined or does not declare any constructors, an
2289 // additional function template derived as above from a hypothetical
2292 Transform.buildSimpleDeductionGuide(None);
2294 // -- An additional function template derived as above from a hypothetical
2295 // constructor C(C), called the copy deduction candidate.
2296 cast<CXXDeductionGuideDecl>(
2297 cast<FunctionTemplateDecl>(
2298 Transform.buildSimpleDeductionGuide(Transform.DeducedType))
2299 ->getTemplatedDecl())
2300 ->setIsCopyDeductionCandidate();
2303 /// Diagnose the presence of a default template argument on a
2304 /// template parameter, which is ill-formed in certain contexts.
2306 /// \returns true if the default template argument should be dropped.
2307 static bool DiagnoseDefaultTemplateArgument(Sema &S,
2308 Sema::TemplateParamListContext TPC,
2309 SourceLocation ParamLoc,
2310 SourceRange DefArgRange) {
2312 case Sema::TPC_ClassTemplate:
2313 case Sema::TPC_VarTemplate:
2314 case Sema::TPC_TypeAliasTemplate:
2317 case Sema::TPC_FunctionTemplate:
2318 case Sema::TPC_FriendFunctionTemplateDefinition:
2319 // C++ [temp.param]p9:
2320 // A default template-argument shall not be specified in a
2321 // function template declaration or a function template
2323 // If a friend function template declaration specifies a default
2324 // template-argument, that declaration shall be a definition and shall be
2325 // the only declaration of the function template in the translation unit.
2326 // (C++98/03 doesn't have this wording; see DR226).
2327 S.Diag(ParamLoc, S.getLangOpts().CPlusPlus11 ?
2328 diag::warn_cxx98_compat_template_parameter_default_in_function_template
2329 : diag::ext_template_parameter_default_in_function_template)
2333 case Sema::TPC_ClassTemplateMember:
2334 // C++0x [temp.param]p9:
2335 // A default template-argument shall not be specified in the
2336 // template-parameter-lists of the definition of a member of a
2337 // class template that appears outside of the member's class.
2338 S.Diag(ParamLoc, diag::err_template_parameter_default_template_member)
2342 case Sema::TPC_FriendClassTemplate:
2343 case Sema::TPC_FriendFunctionTemplate:
2344 // C++ [temp.param]p9:
2345 // A default template-argument shall not be specified in a
2346 // friend template declaration.
2347 S.Diag(ParamLoc, diag::err_template_parameter_default_friend_template)
2351 // FIXME: C++0x [temp.param]p9 allows default template-arguments
2352 // for friend function templates if there is only a single
2353 // declaration (and it is a definition). Strange!
2356 llvm_unreachable("Invalid TemplateParamListContext!");
2359 /// Check for unexpanded parameter packs within the template parameters
2360 /// of a template template parameter, recursively.
2361 static bool DiagnoseUnexpandedParameterPacks(Sema &S,
2362 TemplateTemplateParmDecl *TTP) {
2363 // A template template parameter which is a parameter pack is also a pack
2365 if (TTP->isParameterPack())
2368 TemplateParameterList *Params = TTP->getTemplateParameters();
2369 for (unsigned I = 0, N = Params->size(); I != N; ++I) {
2370 NamedDecl *P = Params->getParam(I);
2371 if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(P)) {
2372 if (!TTP->isParameterPack())
2373 if (const TypeConstraint *TC = TTP->getTypeConstraint())
2374 if (TC->hasExplicitTemplateArgs())
2375 for (auto &ArgLoc : TC->getTemplateArgsAsWritten()->arguments())
2376 if (S.DiagnoseUnexpandedParameterPack(ArgLoc,
2377 Sema::UPPC_TypeConstraint))
2382 if (NonTypeTemplateParmDecl *NTTP = dyn_cast<NonTypeTemplateParmDecl>(P)) {
2383 if (!NTTP->isParameterPack() &&
2384 S.DiagnoseUnexpandedParameterPack(NTTP->getLocation(),
2385 NTTP->getTypeSourceInfo(),
2386 Sema::UPPC_NonTypeTemplateParameterType))
2392 if (TemplateTemplateParmDecl *InnerTTP
2393 = dyn_cast<TemplateTemplateParmDecl>(P))
2394 if (DiagnoseUnexpandedParameterPacks(S, InnerTTP))
2401 /// Checks the validity of a template parameter list, possibly
2402 /// considering the template parameter list from a previous
2405 /// If an "old" template parameter list is provided, it must be
2406 /// equivalent (per TemplateParameterListsAreEqual) to the "new"
2407 /// template parameter list.
2409 /// \param NewParams Template parameter list for a new template
2410 /// declaration. This template parameter list will be updated with any
2411 /// default arguments that are carried through from the previous
2412 /// template parameter list.
2414 /// \param OldParams If provided, template parameter list from a
2415 /// previous declaration of the same template. Default template
2416 /// arguments will be merged from the old template parameter list to
2417 /// the new template parameter list.
2419 /// \param TPC Describes the context in which we are checking the given
2420 /// template parameter list.
2422 /// \param SkipBody If we might have already made a prior merged definition
2423 /// of this template visible, the corresponding body-skipping information.
2424 /// Default argument redefinition is not an error when skipping such a body,
2425 /// because (under the ODR) we can assume the default arguments are the same
2426 /// as the prior merged definition.
2428 /// \returns true if an error occurred, false otherwise.
2429 bool Sema::CheckTemplateParameterList(TemplateParameterList *NewParams,
2430 TemplateParameterList *OldParams,
2431 TemplateParamListContext TPC,
2432 SkipBodyInfo *SkipBody) {
2433 bool Invalid = false;
2435 // C++ [temp.param]p10:
2436 // The set of default template-arguments available for use with a
2437 // template declaration or definition is obtained by merging the
2438 // default arguments from the definition (if in scope) and all
2439 // declarations in scope in the same way default function
2440 // arguments are (8.3.6).
2441 bool SawDefaultArgument = false;
2442 SourceLocation PreviousDefaultArgLoc;
2444 // Dummy initialization to avoid warnings.
2445 TemplateParameterList::iterator OldParam = NewParams->end();
2447 OldParam = OldParams->begin();
2449 bool RemoveDefaultArguments = false;
2450 for (TemplateParameterList::iterator NewParam = NewParams->begin(),
2451 NewParamEnd = NewParams->end();
2452 NewParam != NewParamEnd; ++NewParam) {
2453 // Variables used to diagnose redundant default arguments
2454 bool RedundantDefaultArg = false;
2455 SourceLocation OldDefaultLoc;
2456 SourceLocation NewDefaultLoc;
2458 // Variable used to diagnose missing default arguments
2459 bool MissingDefaultArg = false;
2461 // Variable used to diagnose non-final parameter packs
2462 bool SawParameterPack = false;
2464 if (TemplateTypeParmDecl *NewTypeParm
2465 = dyn_cast<TemplateTypeParmDecl>(*NewParam)) {
2466 // Check the presence of a default argument here.
2467 if (NewTypeParm->hasDefaultArgument() &&
2468 DiagnoseDefaultTemplateArgument(*this, TPC,
2469 NewTypeParm->getLocation(),
2470 NewTypeParm->getDefaultArgumentInfo()->getTypeLoc()
2472 NewTypeParm->removeDefaultArgument();
2474 // Merge default arguments for template type parameters.
2475 TemplateTypeParmDecl *OldTypeParm
2476 = OldParams? cast<TemplateTypeParmDecl>(*OldParam) : nullptr;
2477 if (NewTypeParm->isParameterPack()) {
2478 assert(!NewTypeParm->hasDefaultArgument() &&
2479 "Parameter packs can't have a default argument!");
2480 SawParameterPack = true;
2481 } else if (OldTypeParm && hasVisibleDefaultArgument(OldTypeParm) &&
2482 NewTypeParm->hasDefaultArgument() &&
2483 (!SkipBody || !SkipBody->ShouldSkip)) {
2484 OldDefaultLoc = OldTypeParm->getDefaultArgumentLoc();
2485 NewDefaultLoc = NewTypeParm->getDefaultArgumentLoc();
2486 SawDefaultArgument = true;
2487 RedundantDefaultArg = true;
2488 PreviousDefaultArgLoc = NewDefaultLoc;
2489 } else if (OldTypeParm && OldTypeParm->hasDefaultArgument()) {
2490 // Merge the default argument from the old declaration to the
2492 NewTypeParm->setInheritedDefaultArgument(Context, OldTypeParm);
2493 PreviousDefaultArgLoc = OldTypeParm->getDefaultArgumentLoc();
2494 } else if (NewTypeParm->hasDefaultArgument()) {
2495 SawDefaultArgument = true;
2496 PreviousDefaultArgLoc = NewTypeParm->getDefaultArgumentLoc();
2497 } else if (SawDefaultArgument)
2498 MissingDefaultArg = true;
2499 } else if (NonTypeTemplateParmDecl *NewNonTypeParm
2500 = dyn_cast<NonTypeTemplateParmDecl>(*NewParam)) {
2501 // Check for unexpanded parameter packs.
2502 if (!NewNonTypeParm->isParameterPack() &&
2503 DiagnoseUnexpandedParameterPack(NewNonTypeParm->getLocation(),
2504 NewNonTypeParm->getTypeSourceInfo(),
2505 UPPC_NonTypeTemplateParameterType)) {
2510 // Check the presence of a default argument here.
2511 if (NewNonTypeParm->hasDefaultArgument() &&
2512 DiagnoseDefaultTemplateArgument(*this, TPC,
2513 NewNonTypeParm->getLocation(),
2514 NewNonTypeParm->getDefaultArgument()->getSourceRange())) {
2515 NewNonTypeParm->removeDefaultArgument();
2518 // Merge default arguments for non-type template parameters
2519 NonTypeTemplateParmDecl *OldNonTypeParm
2520 = OldParams? cast<NonTypeTemplateParmDecl>(*OldParam) : nullptr;
2521 if (NewNonTypeParm->isParameterPack()) {
2522 assert(!NewNonTypeParm->hasDefaultArgument() &&
2523 "Parameter packs can't have a default argument!");
2524 if (!NewNonTypeParm->isPackExpansion())
2525 SawParameterPack = true;
2526 } else if (OldNonTypeParm && hasVisibleDefaultArgument(OldNonTypeParm) &&
2527 NewNonTypeParm->hasDefaultArgument() &&
2528 (!SkipBody || !SkipBody->ShouldSkip)) {
2529 OldDefaultLoc = OldNonTypeParm->getDefaultArgumentLoc();
2530 NewDefaultLoc = NewNonTypeParm->getDefaultArgumentLoc();
2531 SawDefaultArgument = true;
2532 RedundantDefaultArg = true;
2533 PreviousDefaultArgLoc = NewDefaultLoc;
2534 } else if (OldNonTypeParm && OldNonTypeParm->hasDefaultArgument()) {
2535 // Merge the default argument from the old declaration to the
2537 NewNonTypeParm->setInheritedDefaultArgument(Context, OldNonTypeParm);
2538 PreviousDefaultArgLoc = OldNonTypeParm->getDefaultArgumentLoc();
2539 } else if (NewNonTypeParm->hasDefaultArgument()) {
2540 SawDefaultArgument = true;
2541 PreviousDefaultArgLoc = NewNonTypeParm->getDefaultArgumentLoc();
2542 } else if (SawDefaultArgument)
2543 MissingDefaultArg = true;
2545 TemplateTemplateParmDecl *NewTemplateParm
2546 = cast<TemplateTemplateParmDecl>(*NewParam);
2548 // Check for unexpanded parameter packs, recursively.
2549 if (::DiagnoseUnexpandedParameterPacks(*this, NewTemplateParm)) {
2554 // Check the presence of a default argument here.
2555 if (NewTemplateParm->hasDefaultArgument() &&
2556 DiagnoseDefaultTemplateArgument(*this, TPC,
2557 NewTemplateParm->getLocation(),
2558 NewTemplateParm->getDefaultArgument().getSourceRange()))
2559 NewTemplateParm->removeDefaultArgument();
2561 // Merge default arguments for template template parameters
2562 TemplateTemplateParmDecl *OldTemplateParm
2563 = OldParams? cast<TemplateTemplateParmDecl>(*OldParam) : nullptr;
2564 if (NewTemplateParm->isParameterPack()) {
2565 assert(!NewTemplateParm->hasDefaultArgument() &&
2566 "Parameter packs can't have a default argument!");
2567 if (!NewTemplateParm->isPackExpansion())
2568 SawParameterPack = true;
2569 } else if (OldTemplateParm &&
2570 hasVisibleDefaultArgument(OldTemplateParm) &&
2571 NewTemplateParm->hasDefaultArgument() &&
2572 (!SkipBody || !SkipBody->ShouldSkip)) {
2573 OldDefaultLoc = OldTemplateParm->getDefaultArgument().getLocation();
2574 NewDefaultLoc = NewTemplateParm->getDefaultArgument().getLocation();
2575 SawDefaultArgument = true;
2576 RedundantDefaultArg = true;
2577 PreviousDefaultArgLoc = NewDefaultLoc;
2578 } else if (OldTemplateParm && OldTemplateParm->hasDefaultArgument()) {
2579 // Merge the default argument from the old declaration to the
2581 NewTemplateParm->setInheritedDefaultArgument(Context, OldTemplateParm);
2582 PreviousDefaultArgLoc
2583 = OldTemplateParm->getDefaultArgument().getLocation();
2584 } else if (NewTemplateParm->hasDefaultArgument()) {
2585 SawDefaultArgument = true;
2586 PreviousDefaultArgLoc
2587 = NewTemplateParm->getDefaultArgument().getLocation();
2588 } else if (SawDefaultArgument)
2589 MissingDefaultArg = true;
2592 // C++11 [temp.param]p11:
2593 // If a template parameter of a primary class template or alias template
2594 // is a template parameter pack, it shall be the last template parameter.
2595 if (SawParameterPack && (NewParam + 1) != NewParamEnd &&
2596 (TPC == TPC_ClassTemplate || TPC == TPC_VarTemplate ||
2597 TPC == TPC_TypeAliasTemplate)) {
2598 Diag((*NewParam)->getLocation(),
2599 diag::err_template_param_pack_must_be_last_template_parameter);
2603 if (RedundantDefaultArg) {
2604 // C++ [temp.param]p12:
2605 // A template-parameter shall not be given default arguments
2606 // by two different declarations in the same scope.
2607 Diag(NewDefaultLoc, diag::err_template_param_default_arg_redefinition);
2608 Diag(OldDefaultLoc, diag::note_template_param_prev_default_arg);
2610 } else if (MissingDefaultArg && TPC != TPC_FunctionTemplate) {
2611 // C++ [temp.param]p11:
2612 // If a template-parameter of a class template has a default
2613 // template-argument, each subsequent template-parameter shall either
2614 // have a default template-argument supplied or be a template parameter
2616 Diag((*NewParam)->getLocation(),
2617 diag::err_template_param_default_arg_missing);
2618 Diag(PreviousDefaultArgLoc, diag::note_template_param_prev_default_arg);
2620 RemoveDefaultArguments = true;
2623 // If we have an old template parameter list that we're merging
2624 // in, move on to the next parameter.
2629 // We were missing some default arguments at the end of the list, so remove
2630 // all of the default arguments.
2631 if (RemoveDefaultArguments) {
2632 for (TemplateParameterList::iterator NewParam = NewParams->begin(),
2633 NewParamEnd = NewParams->end();
2634 NewParam != NewParamEnd; ++NewParam) {
2635 if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(*NewParam))
2636 TTP->removeDefaultArgument();
2637 else if (NonTypeTemplateParmDecl *NTTP
2638 = dyn_cast<NonTypeTemplateParmDecl>(*NewParam))
2639 NTTP->removeDefaultArgument();
2641 cast<TemplateTemplateParmDecl>(*NewParam)->removeDefaultArgument();
2650 /// A class which looks for a use of a certain level of template
2652 struct DependencyChecker : RecursiveASTVisitor<DependencyChecker> {
2653 typedef RecursiveASTVisitor<DependencyChecker> super;
2657 // Whether we're looking for a use of a template parameter that makes the
2658 // overall construct type-dependent / a dependent type. This is strictly
2659 // best-effort for now; we may fail to match at all for a dependent type
2660 // in some cases if this is set.
2661 bool IgnoreNonTypeDependent;
2664 SourceLocation MatchLoc;
2666 DependencyChecker(unsigned Depth, bool IgnoreNonTypeDependent)
2667 : Depth(Depth), IgnoreNonTypeDependent(IgnoreNonTypeDependent),
2670 DependencyChecker(TemplateParameterList *Params, bool IgnoreNonTypeDependent)
2671 : IgnoreNonTypeDependent(IgnoreNonTypeDependent), Match(false) {
2672 NamedDecl *ND = Params->getParam(0);
2673 if (TemplateTypeParmDecl *PD = dyn_cast<TemplateTypeParmDecl>(ND)) {
2674 Depth = PD->getDepth();
2675 } else if (NonTypeTemplateParmDecl *PD =
2676 dyn_cast<NonTypeTemplateParmDecl>(ND)) {
2677 Depth = PD->getDepth();
2679 Depth = cast<TemplateTemplateParmDecl>(ND)->getDepth();
2683 bool Matches(unsigned ParmDepth, SourceLocation Loc = SourceLocation()) {
2684 if (ParmDepth >= Depth) {
2692 bool TraverseStmt(Stmt *S, DataRecursionQueue *Q = nullptr) {
2693 // Prune out non-type-dependent expressions if requested. This can
2694 // sometimes result in us failing to find a template parameter reference
2695 // (if a value-dependent expression creates a dependent type), but this
2696 // mode is best-effort only.
2697 if (auto *E = dyn_cast_or_null<Expr>(S))
2698 if (IgnoreNonTypeDependent && !E->isTypeDependent())
2700 return super::TraverseStmt(S, Q);
2703 bool TraverseTypeLoc(TypeLoc TL) {
2704 if (IgnoreNonTypeDependent && !TL.isNull() &&
2705 !TL.getType()->isDependentType())
2707 return super::TraverseTypeLoc(TL);
2710 bool VisitTemplateTypeParmTypeLoc(TemplateTypeParmTypeLoc TL) {
2711 return !Matches(TL.getTypePtr()->getDepth(), TL.getNameLoc());
2714 bool VisitTemplateTypeParmType(const TemplateTypeParmType *T) {
2715 // For a best-effort search, keep looking until we find a location.
2716 return IgnoreNonTypeDependent || !Matches(T->getDepth());
2719 bool TraverseTemplateName(TemplateName N) {
2720 if (TemplateTemplateParmDecl *PD =
2721 dyn_cast_or_null<TemplateTemplateParmDecl>(N.getAsTemplateDecl()))
2722 if (Matches(PD->getDepth()))
2724 return super::TraverseTemplateName(N);
2727 bool VisitDeclRefExpr(DeclRefExpr *E) {
2728 if (NonTypeTemplateParmDecl *PD =
2729 dyn_cast<NonTypeTemplateParmDecl>(E->getDecl()))
2730 if (Matches(PD->getDepth(), E->getExprLoc()))
2732 return super::VisitDeclRefExpr(E);
2735 bool VisitSubstTemplateTypeParmType(const SubstTemplateTypeParmType *T) {
2736 return TraverseType(T->getReplacementType());
2740 VisitSubstTemplateTypeParmPackType(const SubstTemplateTypeParmPackType *T) {
2741 return TraverseTemplateArgument(T->getArgumentPack());
2744 bool TraverseInjectedClassNameType(const InjectedClassNameType *T) {
2745 return TraverseType(T->getInjectedSpecializationType());
2748 } // end anonymous namespace
2750 /// Determines whether a given type depends on the given parameter
2753 DependsOnTemplateParameters(QualType T, TemplateParameterList *Params) {
2754 if (!Params->size())
2757 DependencyChecker Checker(Params, /*IgnoreNonTypeDependent*/false);
2758 Checker.TraverseType(T);
2759 return Checker.Match;
2762 // Find the source range corresponding to the named type in the given
2763 // nested-name-specifier, if any.
2764 static SourceRange getRangeOfTypeInNestedNameSpecifier(ASTContext &Context,
2766 const CXXScopeSpec &SS) {
2767 NestedNameSpecifierLoc NNSLoc(SS.getScopeRep(), SS.location_data());
2768 while (NestedNameSpecifier *NNS = NNSLoc.getNestedNameSpecifier()) {
2769 if (const Type *CurType = NNS->getAsType()) {
2770 if (Context.hasSameUnqualifiedType(T, QualType(CurType, 0)))
2771 return NNSLoc.getTypeLoc().getSourceRange();
2775 NNSLoc = NNSLoc.getPrefix();
2778 return SourceRange();
2781 /// Match the given template parameter lists to the given scope
2782 /// specifier, returning the template parameter list that applies to the
2785 /// \param DeclStartLoc the start of the declaration that has a scope
2786 /// specifier or a template parameter list.
2788 /// \param DeclLoc The location of the declaration itself.
2790 /// \param SS the scope specifier that will be matched to the given template
2791 /// parameter lists. This scope specifier precedes a qualified name that is
2794 /// \param TemplateId The template-id following the scope specifier, if there
2795 /// is one. Used to check for a missing 'template<>'.
2797 /// \param ParamLists the template parameter lists, from the outermost to the
2798 /// innermost template parameter lists.
2800 /// \param IsFriend Whether to apply the slightly different rules for
2801 /// matching template parameters to scope specifiers in friend
2804 /// \param IsMemberSpecialization will be set true if the scope specifier
2805 /// denotes a fully-specialized type, and therefore this is a declaration of
2806 /// a member specialization.
2808 /// \returns the template parameter list, if any, that corresponds to the
2809 /// name that is preceded by the scope specifier @p SS. This template
2810 /// parameter list may have template parameters (if we're declaring a
2811 /// template) or may have no template parameters (if we're declaring a
2812 /// template specialization), or may be NULL (if what we're declaring isn't
2813 /// itself a template).
2814 TemplateParameterList *Sema::MatchTemplateParametersToScopeSpecifier(
2815 SourceLocation DeclStartLoc, SourceLocation DeclLoc, const CXXScopeSpec &SS,
2816 TemplateIdAnnotation *TemplateId,
2817 ArrayRef<TemplateParameterList *> ParamLists, bool IsFriend,
2818 bool &IsMemberSpecialization, bool &Invalid, bool SuppressDiagnostic) {
2819 IsMemberSpecialization = false;
2822 // The sequence of nested types to which we will match up the template
2823 // parameter lists. We first build this list by starting with the type named
2824 // by the nested-name-specifier and walking out until we run out of types.
2825 SmallVector<QualType, 4> NestedTypes;
2827 if (SS.getScopeRep()) {
2828 if (CXXRecordDecl *Record
2829 = dyn_cast_or_null<CXXRecordDecl>(computeDeclContext(SS, true)))
2830 T = Context.getTypeDeclType(Record);
2832 T = QualType(SS.getScopeRep()->getAsType(), 0);
2835 // If we found an explicit specialization that prevents us from needing
2836 // 'template<>' headers, this will be set to the location of that
2837 // explicit specialization.
2838 SourceLocation ExplicitSpecLoc;
2840 while (!T.isNull()) {
2841 NestedTypes.push_back(T);
2843 // Retrieve the parent of a record type.
2844 if (CXXRecordDecl *Record = T->getAsCXXRecordDecl()) {
2845 // If this type is an explicit specialization, we're done.
2846 if (ClassTemplateSpecializationDecl *Spec
2847 = dyn_cast<ClassTemplateSpecializationDecl>(Record)) {
2848 if (!isa<ClassTemplatePartialSpecializationDecl>(Spec) &&
2849 Spec->getSpecializationKind() == TSK_ExplicitSpecialization) {
2850 ExplicitSpecLoc = Spec->getLocation();
2853 } else if (Record->getTemplateSpecializationKind()
2854 == TSK_ExplicitSpecialization) {
2855 ExplicitSpecLoc = Record->getLocation();
2859 if (TypeDecl *Parent = dyn_cast<TypeDecl>(Record->getParent()))
2860 T = Context.getTypeDeclType(Parent);
2866 if (const TemplateSpecializationType *TST
2867 = T->getAs<TemplateSpecializationType>()) {
2868 if (TemplateDecl *Template = TST->getTemplateName().getAsTemplateDecl()) {
2869 if (TypeDecl *Parent = dyn_cast<TypeDecl>(Template->getDeclContext()))
2870 T = Context.getTypeDeclType(Parent);
2877 // Look one step prior in a dependent template specialization type.
2878 if (const DependentTemplateSpecializationType *DependentTST
2879 = T->getAs<DependentTemplateSpecializationType>()) {
2880 if (NestedNameSpecifier *NNS = DependentTST->getQualifier())
2881 T = QualType(NNS->getAsType(), 0);
2887 // Look one step prior in a dependent name type.
2888 if (const DependentNameType *DependentName = T->getAs<DependentNameType>()){
2889 if (NestedNameSpecifier *NNS = DependentName->getQualifier())
2890 T = QualType(NNS->getAsType(), 0);
2896 // Retrieve the parent of an enumeration type.
2897 if (const EnumType *EnumT = T->getAs<EnumType>()) {
2898 // FIXME: Forward-declared enums require a TSK_ExplicitSpecialization
2900 EnumDecl *Enum = EnumT->getDecl();
2902 // Get to the parent type.
2903 if (TypeDecl *Parent = dyn_cast<TypeDecl>(Enum->getParent()))
2904 T = Context.getTypeDeclType(Parent);
2912 // Reverse the nested types list, since we want to traverse from the outermost
2913 // to the innermost while checking template-parameter-lists.
2914 std::reverse(NestedTypes.begin(), NestedTypes.end());
2916 // C++0x [temp.expl.spec]p17:
2917 // A member or a member template may be nested within many
2918 // enclosing class templates. In an explicit specialization for
2919 // such a member, the member declaration shall be preceded by a
2920 // template<> for each enclosing class template that is
2921 // explicitly specialized.
2922 bool SawNonEmptyTemplateParameterList = false;
2924 auto CheckExplicitSpecialization = [&](SourceRange Range, bool Recovery) {
2925 if (SawNonEmptyTemplateParameterList) {
2926 if (!SuppressDiagnostic)
2927 Diag(DeclLoc, diag::err_specialize_member_of_template)
2928 << !Recovery << Range;
2930 IsMemberSpecialization = false;
2937 auto DiagnoseMissingExplicitSpecialization = [&] (SourceRange Range) {
2938 // Check that we can have an explicit specialization here.
2939 if (CheckExplicitSpecialization(Range, true))
2942 // We don't have a template header, but we should.
2943 SourceLocation ExpectedTemplateLoc;
2944 if (!ParamLists.empty())
2945 ExpectedTemplateLoc = ParamLists[0]->getTemplateLoc();
2947 ExpectedTemplateLoc = DeclStartLoc;
2949 if (!SuppressDiagnostic)
2950 Diag(DeclLoc, diag::err_template_spec_needs_header)
2952 << FixItHint::CreateInsertion(ExpectedTemplateLoc, "template<> ");
2956 unsigned ParamIdx = 0;
2957 for (unsigned TypeIdx = 0, NumTypes = NestedTypes.size(); TypeIdx != NumTypes;
2959 T = NestedTypes[TypeIdx];
2961 // Whether we expect a 'template<>' header.
2962 bool NeedEmptyTemplateHeader = false;
2964 // Whether we expect a template header with parameters.
2965 bool NeedNonemptyTemplateHeader = false;
2967 // For a dependent type, the set of template parameters that we
2969 TemplateParameterList *ExpectedTemplateParams = nullptr;
2971 // C++0x [temp.expl.spec]p15:
2972 // A member or a member template may be nested within many enclosing
2973 // class templates. In an explicit specialization for such a member, the
2974 // member declaration shall be preceded by a template<> for each
2975 // enclosing class template that is explicitly specialized.
2976 if (CXXRecordDecl *Record = T->getAsCXXRecordDecl()) {
2977 if (ClassTemplatePartialSpecializationDecl *Partial
2978 = dyn_cast<ClassTemplatePartialSpecializationDecl>(Record)) {
2979 ExpectedTemplateParams = Partial->getTemplateParameters();
2980 NeedNonemptyTemplateHeader = true;
2981 } else if (Record->isDependentType()) {
2982 if (Record->getDescribedClassTemplate()) {
2983 ExpectedTemplateParams = Record->getDescribedClassTemplate()
2984 ->getTemplateParameters();
2985 NeedNonemptyTemplateHeader = true;
2987 } else if (ClassTemplateSpecializationDecl *Spec
2988 = dyn_cast<ClassTemplateSpecializationDecl>(Record)) {
2989 // C++0x [temp.expl.spec]p4:
2990 // Members of an explicitly specialized class template are defined
2991 // in the same manner as members of normal classes, and not using
2992 // the template<> syntax.
2993 if (Spec->getSpecializationKind() != TSK_ExplicitSpecialization)
2994 NeedEmptyTemplateHeader = true;
2997 } else if (Record->getTemplateSpecializationKind()) {
2998 if (Record->getTemplateSpecializationKind()
2999 != TSK_ExplicitSpecialization &&
3000 TypeIdx == NumTypes - 1)
3001 IsMemberSpecialization = true;
3005 } else if (const TemplateSpecializationType *TST
3006 = T->getAs<TemplateSpecializationType>()) {
3007 if (TemplateDecl *Template = TST->getTemplateName().getAsTemplateDecl()) {
3008 ExpectedTemplateParams = Template->getTemplateParameters();
3009 NeedNonemptyTemplateHeader = true;
3011 } else if (T->getAs<DependentTemplateSpecializationType>()) {
3012 // FIXME: We actually could/should check the template arguments here
3013 // against the corresponding template parameter list.
3014 NeedNonemptyTemplateHeader = false;
3017 // C++ [temp.expl.spec]p16:
3018 // In an explicit specialization declaration for a member of a class
3019 // template or a member template that ap- pears in namespace scope, the
3020 // member template and some of its enclosing class templates may remain
3021 // unspecialized, except that the declaration shall not explicitly
3022 // specialize a class member template if its en- closing class templates
3023 // are not explicitly specialized as well.
3024 if (ParamIdx < ParamLists.size()) {
3025 if (ParamLists[ParamIdx]->size() == 0) {
3026 if (CheckExplicitSpecialization(ParamLists[ParamIdx]->getSourceRange(),
3030 SawNonEmptyTemplateParameterList = true;
3033 if (NeedEmptyTemplateHeader) {
3034 // If we're on the last of the types, and we need a 'template<>' header
3035 // here, then it's a member specialization.
3036 if (TypeIdx == NumTypes - 1)
3037 IsMemberSpecialization = true;
3039 if (ParamIdx < ParamLists.size()) {
3040 if (ParamLists[ParamIdx]->size() > 0) {
3041 // The header has template parameters when it shouldn't. Complain.
3042 if (!SuppressDiagnostic)
3043 Diag(ParamLists[ParamIdx]->getTemplateLoc(),
3044 diag::err_template_param_list_matches_nontemplate)
3046 << SourceRange(ParamLists[ParamIdx]->getLAngleLoc(),
3047 ParamLists[ParamIdx]->getRAngleLoc())
3048 << getRangeOfTypeInNestedNameSpecifier(Context, T, SS);
3053 // Consume this template header.
3059 if (DiagnoseMissingExplicitSpecialization(
3060 getRangeOfTypeInNestedNameSpecifier(Context, T, SS)))
3066 if (NeedNonemptyTemplateHeader) {
3067 // In friend declarations we can have template-ids which don't
3068 // depend on the corresponding template parameter lists. But
3069 // assume that empty parameter lists are supposed to match this
3071 if (IsFriend && T->isDependentType()) {
3072 if (ParamIdx < ParamLists.size() &&
3073 DependsOnTemplateParameters(T, ParamLists[ParamIdx]))
3074 ExpectedTemplateParams = nullptr;
3079 if (ParamIdx < ParamLists.size()) {
3080 // Check the template parameter list, if we can.
3081 if (ExpectedTemplateParams &&
3082 !TemplateParameterListsAreEqual(ParamLists[ParamIdx],
3083 ExpectedTemplateParams,
3084 !SuppressDiagnostic, TPL_TemplateMatch))
3088 CheckTemplateParameterList(ParamLists[ParamIdx], nullptr,
3089 TPC_ClassTemplateMember))
3096 if (!SuppressDiagnostic)
3097 Diag(DeclLoc, diag::err_template_spec_needs_template_parameters)
3099 << getRangeOfTypeInNestedNameSpecifier(Context, T, SS);
3105 // If there were at least as many template-ids as there were template
3106 // parameter lists, then there are no template parameter lists remaining for
3107 // the declaration itself.
3108 if (ParamIdx >= ParamLists.size()) {
3109 if (TemplateId && !IsFriend) {
3110 // We don't have a template header for the declaration itself, but we
3112 DiagnoseMissingExplicitSpecialization(SourceRange(TemplateId->LAngleLoc,
3113 TemplateId->RAngleLoc));
3115 // Fabricate an empty template parameter list for the invented header.
3116 return TemplateParameterList::Create(Context, SourceLocation(),
3117 SourceLocation(), None,
3118 SourceLocation(), nullptr);
3124 // If there were too many template parameter lists, complain about that now.
3125 if (ParamIdx < ParamLists.size() - 1) {
3126 bool HasAnyExplicitSpecHeader = false;
3127 bool AllExplicitSpecHeaders = true;
3128 for (unsigned I = ParamIdx, E = ParamLists.size() - 1; I != E; ++I) {
3129 if (ParamLists[I]->size() == 0)
3130 HasAnyExplicitSpecHeader = true;
3132 AllExplicitSpecHeaders = false;
3135 if (!SuppressDiagnostic)
3136 Diag(ParamLists[ParamIdx]->getTemplateLoc(),
3137 AllExplicitSpecHeaders ? diag::warn_template_spec_extra_headers
3138 : diag::err_template_spec_extra_headers)
3139 << SourceRange(ParamLists[ParamIdx]->getTemplateLoc(),
3140 ParamLists[ParamLists.size() - 2]->getRAngleLoc());
3142 // If there was a specialization somewhere, such that 'template<>' is
3143 // not required, and there were any 'template<>' headers, note where the
3144 // specialization occurred.
3145 if (ExplicitSpecLoc.isValid() && HasAnyExplicitSpecHeader &&
3146 !SuppressDiagnostic)
3147 Diag(ExplicitSpecLoc,
3148 diag::note_explicit_template_spec_does_not_need_header)
3149 << NestedTypes.back();
3151 // We have a template parameter list with no corresponding scope, which
3152 // means that the resulting template declaration can't be instantiated
3153 // properly (we'll end up with dependent nodes when we shouldn't).
3154 if (!AllExplicitSpecHeaders)
3158 // C++ [temp.expl.spec]p16:
3159 // In an explicit specialization declaration for a member of a class
3160 // template or a member template that ap- pears in namespace scope, the
3161 // member template and some of its enclosing class templates may remain
3162 // unspecialized, except that the declaration shall not explicitly
3163 // specialize a class member template if its en- closing class templates
3164 // are not explicitly specialized as well.
3165 if (ParamLists.back()->size() == 0 &&
3166 CheckExplicitSpecialization(ParamLists[ParamIdx]->getSourceRange(),
3170 // Return the last template parameter list, which corresponds to the
3171 // entity being declared.
3172 return ParamLists.back();
3175 void Sema::NoteAllFoundTemplates(TemplateName Name) {
3176 if (TemplateDecl *Template = Name.getAsTemplateDecl()) {
3177 Diag(Template->getLocation(), diag::note_template_declared_here)
3178 << (isa<FunctionTemplateDecl>(Template)
3180 : isa<ClassTemplateDecl>(Template)
3182 : isa<VarTemplateDecl>(Template)
3184 : isa<TypeAliasTemplateDecl>(Template) ? 3 : 4)
3185 << Template->getDeclName();
3189 if (OverloadedTemplateStorage *OST = Name.getAsOverloadedTemplate()) {
3190 for (OverloadedTemplateStorage::iterator I = OST->begin(),
3193 Diag((*I)->getLocation(), diag::note_template_declared_here)
3194 << 0 << (*I)->getDeclName();
3201 checkBuiltinTemplateIdType(Sema &SemaRef, BuiltinTemplateDecl *BTD,
3202 const SmallVectorImpl<TemplateArgument> &Converted,
3203 SourceLocation TemplateLoc,
3204 TemplateArgumentListInfo &TemplateArgs) {
3205 ASTContext &Context = SemaRef.getASTContext();
3206 switch (BTD->getBuiltinTemplateKind()) {
3207 case BTK__make_integer_seq: {
3208 // Specializations of __make_integer_seq<S, T, N> are treated like
3209 // S<T, 0, ..., N-1>.
3211 // C++14 [inteseq.intseq]p1:
3212 // T shall be an integer type.
3213 if (!Converted[1].getAsType()->isIntegralType(Context)) {
3214 SemaRef.Diag(TemplateArgs[1].getLocation(),
3215 diag::err_integer_sequence_integral_element_type);
3219 // C++14 [inteseq.make]p1:
3220 // If N is negative the program is ill-formed.
3221 TemplateArgument NumArgsArg = Converted[2];
3222 llvm::APSInt NumArgs = NumArgsArg.getAsIntegral();
3224 SemaRef.Diag(TemplateArgs[2].getLocation(),
3225 diag::err_integer_sequence_negative_length);
3229 QualType ArgTy = NumArgsArg.getIntegralType();
3230 TemplateArgumentListInfo SyntheticTemplateArgs;
3231 // The type argument gets reused as the first template argument in the
3232 // synthetic template argument list.
3233 SyntheticTemplateArgs.addArgument(TemplateArgs[1]);
3234 // Expand N into 0 ... N-1.
3235 for (llvm::APSInt I(NumArgs.getBitWidth(), NumArgs.isUnsigned());
3237 TemplateArgument TA(Context, I, ArgTy);
3238 SyntheticTemplateArgs.addArgument(SemaRef.getTrivialTemplateArgumentLoc(
3239 TA, ArgTy, TemplateArgs[2].getLocation()));
3241 // The first template argument will be reused as the template decl that
3242 // our synthetic template arguments will be applied to.
3243 return SemaRef.CheckTemplateIdType(Converted[0].getAsTemplate(),
3244 TemplateLoc, SyntheticTemplateArgs);
3247 case BTK__type_pack_element:
3248 // Specializations of
3249 // __type_pack_element<Index, T_1, ..., T_N>
3250 // are treated like T_Index.
3251 assert(Converted.size() == 2 &&
3252 "__type_pack_element should be given an index and a parameter pack");
3254 // If the Index is out of bounds, the program is ill-formed.
3255 TemplateArgument IndexArg = Converted[0], Ts = Converted[1];
3256 llvm::APSInt Index = IndexArg.getAsIntegral();
3257 assert(Index >= 0 && "the index used with __type_pack_element should be of "
3258 "type std::size_t, and hence be non-negative");
3259 if (Index >= Ts.pack_size()) {
3260 SemaRef.Diag(TemplateArgs[0].getLocation(),
3261 diag::err_type_pack_element_out_of_bounds);
3265 // We simply return the type at index `Index`.
3266 auto Nth = std::next(Ts.pack_begin(), Index.getExtValue());
3267 return Nth->getAsType();
3269 llvm_unreachable("unexpected BuiltinTemplateDecl!");
3272 /// Determine whether this alias template is "enable_if_t".
3273 static bool isEnableIfAliasTemplate(TypeAliasTemplateDecl *AliasTemplate) {
3274 return AliasTemplate->getName().equals("enable_if_t");
3277 /// Collect all of the separable terms in the given condition, which
3278 /// might be a conjunction.
3280 /// FIXME: The right answer is to convert the logical expression into
3281 /// disjunctive normal form, so we can find the first failed term
3282 /// within each possible clause.
3283 static void collectConjunctionTerms(Expr *Clause,
3284 SmallVectorImpl<Expr *> &Terms) {
3285 if (auto BinOp = dyn_cast<BinaryOperator>(Clause->IgnoreParenImpCasts())) {
3286 if (BinOp->getOpcode() == BO_LAnd) {
3287 collectConjunctionTerms(BinOp->getLHS(), Terms);
3288 collectConjunctionTerms(BinOp->getRHS(), Terms);
3294 Terms.push_back(Clause);
3297 // The ranges-v3 library uses an odd pattern of a top-level "||" with
3298 // a left-hand side that is value-dependent but never true. Identify
3299 // the idiom and ignore that term.
3300 static Expr *lookThroughRangesV3Condition(Preprocessor &PP, Expr *Cond) {
3302 auto *BinOp = dyn_cast<BinaryOperator>(Cond->IgnoreParenImpCasts());
3303 if (!BinOp) return Cond;
3305 if (BinOp->getOpcode() != BO_LOr) return Cond;
3307 // With an inner '==' that has a literal on the right-hand side.
3308 Expr *LHS = BinOp->getLHS();
3309 auto *InnerBinOp = dyn_cast<BinaryOperator>(LHS->IgnoreParenImpCasts());
3310 if (!InnerBinOp) return Cond;
3312 if (InnerBinOp->getOpcode() != BO_EQ ||
3313 !isa<IntegerLiteral>(InnerBinOp->getRHS()))
3316 // If the inner binary operation came from a macro expansion named
3317 // CONCEPT_REQUIRES or CONCEPT_REQUIRES_, return the right-hand side
3318 // of the '||', which is the real, user-provided condition.
3319 SourceLocation Loc = InnerBinOp->getExprLoc();
3320 if (!Loc.isMacroID()) return Cond;
3322 StringRef MacroName = PP.getImmediateMacroName(Loc);
3323 if (MacroName == "CONCEPT_REQUIRES" || MacroName == "CONCEPT_REQUIRES_")
3324 return BinOp->getRHS();
3331 // A PrinterHelper that prints more helpful diagnostics for some sub-expressions
3332 // within failing boolean expression, such as substituting template parameters
3333 // for actual types.
3334 class FailedBooleanConditionPrinterHelper : public PrinterHelper {
3336 explicit FailedBooleanConditionPrinterHelper(const PrintingPolicy &P)
3339 bool handledStmt(Stmt *E, raw_ostream &OS) override {
3340 const auto *DR = dyn_cast<DeclRefExpr>(E);
3341 if (DR && DR->getQualifier()) {
3342 // If this is a qualified name, expand the template arguments in nested
3344 DR->getQualifier()->print(OS, Policy, true);
3345 // Then print the decl itself.
3346 const ValueDecl *VD = DR->getDecl();
3347 OS << VD->getName();
3348 if (const auto *IV = dyn_cast<VarTemplateSpecializationDecl>(VD)) {
3349 // This is a template variable, print the expanded template arguments.
3350 printTemplateArgumentList(OS, IV->getTemplateArgs().asArray(), Policy);
3358 const PrintingPolicy Policy;
3361 } // end anonymous namespace
3363 std::pair<Expr *, std::string>
3364 Sema::findFailedBooleanCondition(Expr *Cond) {
3365 Cond = lookThroughRangesV3Condition(PP, Cond);
3367 // Separate out all of the terms in a conjunction.
3368 SmallVector<Expr *, 4> Terms;
3369 collectConjunctionTerms(Cond, Terms);
3371 // Determine which term failed.
3372 Expr *FailedCond = nullptr;
3373 for (Expr *Term : Terms) {
3374 Expr *TermAsWritten = Term->IgnoreParenImpCasts();
3376 // Literals are uninteresting.
3377 if (isa<CXXBoolLiteralExpr>(TermAsWritten) ||
3378 isa<IntegerLiteral>(TermAsWritten))
3381 // The initialization of the parameter from the argument is
3382 // a constant-evaluated context.
3383 EnterExpressionEvaluationContext ConstantEvaluated(
3384 *this, Sema::ExpressionEvaluationContext::ConstantEvaluated);
3387 if (Term->EvaluateAsBooleanCondition(Succeeded, Context) &&
3389 FailedCond = TermAsWritten;
3394 FailedCond = Cond->IgnoreParenImpCasts();
3396 std::string Description;
3398 llvm::raw_string_ostream Out(Description);
3399 PrintingPolicy Policy = getPrintingPolicy();
3400 Policy.PrintCanonicalTypes = true;
3401 FailedBooleanConditionPrinterHelper Helper(Policy);
3402 FailedCond->printPretty(Out, &Helper, Policy, 0, "\n", nullptr);
3404 return { FailedCond, Description };
3407 QualType Sema::CheckTemplateIdType(TemplateName Name,
3408 SourceLocation TemplateLoc,
3409 TemplateArgumentListInfo &TemplateArgs) {
3410 DependentTemplateName *DTN
3411 = Name.getUnderlying().getAsDependentTemplateName();
3412 if (DTN && DTN->isIdentifier())
3413 // When building a template-id where the template-name is dependent,
3414 // assume the template is a type template. Either our assumption is
3415 // correct, or the code is ill-formed and will be diagnosed when the
3416 // dependent name is substituted.
3417 return Context.getDependentTemplateSpecializationType(ETK_None,
3418 DTN->getQualifier(),
3419 DTN->getIdentifier(),
3422 TemplateDecl *Template = Name.getAsTemplateDecl();
3423 if (!Template || isa<FunctionTemplateDecl>(Template) ||
3424 isa<VarTemplateDecl>(Template) || isa<ConceptDecl>(Template)) {
3425 // We might have a substituted template template parameter pack. If so,
3426 // build a template specialization type for it.
3427 if (Name.getAsSubstTemplateTemplateParmPack())
3428 return Context.getTemplateSpecializationType(Name, TemplateArgs);
3430 Diag(TemplateLoc, diag::err_template_id_not_a_type)
3432 NoteAllFoundTemplates(Name);
3436 // Check that the template argument list is well-formed for this
3438 SmallVector<TemplateArgument, 4> Converted;
3439 if (CheckTemplateArgumentList(Template, TemplateLoc, TemplateArgs,
3441 /*UpdateArgsWithConversion=*/true))
3446 bool InstantiationDependent = false;
3447 if (TypeAliasTemplateDecl *AliasTemplate =
3448 dyn_cast<TypeAliasTemplateDecl>(Template)) {
3450 // Find the canonical type for this type alias template specialization.
3451 TypeAliasDecl *Pattern = AliasTemplate->getTemplatedDecl();
3452 if (Pattern->isInvalidDecl())
3455 TemplateArgumentList StackTemplateArgs(TemplateArgumentList::OnStack,
3458 // Only substitute for the innermost template argument list.
3459 MultiLevelTemplateArgumentList TemplateArgLists;
3460 TemplateArgLists.addOuterTemplateArguments(&StackTemplateArgs);
3461 unsigned Depth = AliasTemplate->getTemplateParameters()->getDepth();
3462 for (unsigned I = 0; I < Depth; ++I)
3463 TemplateArgLists.addOuterTemplateArguments(None);
3465 LocalInstantiationScope Scope(*this);
3466 InstantiatingTemplate Inst(*this, TemplateLoc, Template);
3467 if (Inst.isInvalid())
3470 CanonType = SubstType(Pattern->getUnderlyingType(),
3471 TemplateArgLists, AliasTemplate->getLocation(),
3472 AliasTemplate->getDeclName());
3473 if (CanonType.isNull()) {
3474 // If this was enable_if and we failed to find the nested type
3475 // within enable_if in a SFINAE context, dig out the specific
3476 // enable_if condition that failed and present that instead.
3477 if (isEnableIfAliasTemplate(AliasTemplate)) {
3478 if (auto DeductionInfo = isSFINAEContext()) {
3479 if (*DeductionInfo &&
3480 (*DeductionInfo)->hasSFINAEDiagnostic() &&
3481 (*DeductionInfo)->peekSFINAEDiagnostic().second.getDiagID() ==
3482 diag::err_typename_nested_not_found_enable_if &&
3483 TemplateArgs[0].getArgument().getKind()
3484 == TemplateArgument::Expression) {
3486 std::string FailedDescription;
3487 std::tie(FailedCond, FailedDescription) =
3488 findFailedBooleanCondition(TemplateArgs[0].getSourceExpression());
3490 // Remove the old SFINAE diagnostic.
3491 PartialDiagnosticAt OldDiag =
3492 {SourceLocation(), PartialDiagnostic::NullDiagnostic()};
3493 (*DeductionInfo)->takeSFINAEDiagnostic(OldDiag);
3495 // Add a new SFINAE diagnostic specifying which condition
3497 (*DeductionInfo)->addSFINAEDiagnostic(
3499 PDiag(diag::err_typename_nested_not_found_requirement)
3500 << FailedDescription
3501 << FailedCond->getSourceRange());
3508 } else if (Name.isDependent() ||
3509 TemplateSpecializationType::anyDependentTemplateArguments(
3510 TemplateArgs, InstantiationDependent)) {
3511 // This class template specialization is a dependent
3512 // type. Therefore, its canonical type is another class template
3513 // specialization type that contains all of the converted
3514 // arguments in canonical form. This ensures that, e.g., A<T> and
3515 // A<T, T> have identical types when A is declared as:
3517 // template<typename T, typename U = T> struct A;
3518 CanonType = Context.getCanonicalTemplateSpecializationType(Name, Converted);
3520 // This might work out to be a current instantiation, in which
3521 // case the canonical type needs to be the InjectedClassNameType.
3523 // TODO: in theory this could be a simple hashtable lookup; most
3524 // changes to CurContext don't change the set of current
3526 if (isa<ClassTemplateDecl>(Template)) {
3527 for (DeclContext *Ctx = CurContext; Ctx; Ctx = Ctx->getLookupParent()) {
3528 // If we get out to a namespace, we're done.
3529 if (Ctx->isFileContext()) break;
3531 // If this isn't a record, keep looking.
3532 CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(Ctx);
3533 if (!Record) continue;
3535 // Look for one of the two cases with InjectedClassNameTypes
3536 // and check whether it's the same template.
3537 if (!isa<ClassTemplatePartialSpecializationDecl>(Record) &&
3538 !Record->getDescribedClassTemplate())
3541 // Fetch the injected class name type and check whether its
3542 // injected type is equal to the type we just built.
3543 QualType ICNT = Context.getTypeDeclType(Record);
3544 QualType Injected = cast<InjectedClassNameType>(ICNT)
3545 ->getInjectedSpecializationType();
3547 if (CanonType != Injected->getCanonicalTypeInternal())
3550 // If so, the canonical type of this TST is the injected
3551 // class name type of the record we just found.
3552 assert(ICNT.isCanonical());
3557 } else if (ClassTemplateDecl *ClassTemplate
3558 = dyn_cast<ClassTemplateDecl>(Template)) {
3559 // Find the class template specialization declaration that
3560 // corresponds to these arguments.
3561 void *InsertPos = nullptr;
3562 ClassTemplateSpecializationDecl *Decl
3563 = ClassTemplate->findSpecialization(Converted, InsertPos);
3565 // This is the first time we have referenced this class template
3566 // specialization. Create the canonical declaration and add it to
3567 // the set of specializations.
3568 Decl = ClassTemplateSpecializationDecl::Create(
3569 Context, ClassTemplate->getTemplatedDecl()->getTagKind(),
3570 ClassTemplate->getDeclContext(),
3571 ClassTemplate->getTemplatedDecl()->getBeginLoc(),
3572 ClassTemplate->getLocation(), ClassTemplate, Converted, nullptr);
3573 ClassTemplate->AddSpecialization(Decl, InsertPos);
3574 if (ClassTemplate->isOutOfLine())
3575 Decl->setLexicalDeclContext(ClassTemplate->getLexicalDeclContext());
3578 if (Decl->getSpecializationKind() == TSK_Undeclared) {
3579 MultiLevelTemplateArgumentList TemplateArgLists;
3580 TemplateArgLists.addOuterTemplateArguments(Converted);
3581 InstantiateAttrsForDecl(TemplateArgLists, ClassTemplate->getTemplatedDecl(),
3585 // Diagnose uses of this specialization.
3586 (void)DiagnoseUseOfDecl(Decl, TemplateLoc);
3588 CanonType = Context.getTypeDeclType(Decl);
3589 assert(isa<RecordType>(CanonType) &&
3590 "type of non-dependent specialization is not a RecordType");
3591 } else if (auto *BTD = dyn_cast<BuiltinTemplateDecl>(Template)) {
3592 CanonType = checkBuiltinTemplateIdType(*this, BTD, Converted, TemplateLoc,
3596 // Build the fully-sugared type for this class template
3597 // specialization, which refers back to the class template
3598 // specialization we created or found.
3599 return Context.getTemplateSpecializationType(Name, TemplateArgs, CanonType);
3602 void Sema::ActOnUndeclaredTypeTemplateName(Scope *S, TemplateTy &ParsedName,
3603 TemplateNameKind &TNK,
3604 SourceLocation NameLoc,
3605 IdentifierInfo *&II) {
3606 assert(TNK == TNK_Undeclared_template && "not an undeclared template name");
3608 TemplateName Name = ParsedName.get();
3609 auto *ATN = Name.getAsAssumedTemplateName();
3610 assert(ATN && "not an assumed template name");
3611 II = ATN->getDeclName().getAsIdentifierInfo();
3613 if (!resolveAssumedTemplateNameAsType(S, Name, NameLoc, /*Diagnose*/false)) {
3614 // Resolved to a type template name.
3615 ParsedName = TemplateTy::make(Name);
3616 TNK = TNK_Type_template;
3620 bool Sema::resolveAssumedTemplateNameAsType(Scope *S, TemplateName &Name,
3621 SourceLocation NameLoc,
3623 // We assumed this undeclared identifier to be an (ADL-only) function
3624 // template name, but it was used in a context where a type was required.
3625 // Try to typo-correct it now.
3626 AssumedTemplateStorage *ATN = Name.getAsAssumedTemplateName();
3627 assert(ATN && "not an assumed template name");
3629 LookupResult R(*this, ATN->getDeclName(), NameLoc, LookupOrdinaryName);
3630 struct CandidateCallback : CorrectionCandidateCallback {
3631 bool ValidateCandidate(const TypoCorrection &TC) override {
3632 return TC.getCorrectionDecl() &&
3633 getAsTypeTemplateDecl(TC.getCorrectionDecl());
3635 std::unique_ptr<CorrectionCandidateCallback> clone() override {
3636 return std::make_unique<CandidateCallback>(*this);
3640 TypoCorrection Corrected =
3641 CorrectTypo(R.getLookupNameInfo(), R.getLookupKind(), S, nullptr,
3642 FilterCCC, CTK_ErrorRecovery);
3643 if (Corrected && Corrected.getFoundDecl()) {
3644 diagnoseTypo(Corrected, PDiag(diag::err_no_template_suggest)
3645 << ATN->getDeclName());
3646 Name = TemplateName(Corrected.getCorrectionDeclAs<TemplateDecl>());
3651 Diag(R.getNameLoc(), diag::err_no_template) << R.getLookupName();
3655 TypeResult Sema::ActOnTemplateIdType(
3656 Scope *S, CXXScopeSpec &SS, SourceLocation TemplateKWLoc,
3657 TemplateTy TemplateD, IdentifierInfo *TemplateII,
3658 SourceLocation TemplateIILoc, SourceLocation LAngleLoc,
3659 ASTTemplateArgsPtr TemplateArgsIn, SourceLocation RAngleLoc,
3660 bool IsCtorOrDtorName, bool IsClassName) {
3664 if (!IsCtorOrDtorName && !IsClassName && SS.isSet()) {
3665 DeclContext *LookupCtx = computeDeclContext(SS, /*EnteringContext*/false);
3667 // C++ [temp.res]p3:
3668 // A qualified-id that refers to a type and in which the
3669 // nested-name-specifier depends on a template-parameter (14.6.2)
3670 // shall be prefixed by the keyword typename to indicate that the
3671 // qualified-id denotes a type, forming an
3672 // elaborated-type-specifier (7.1.5.3).
3673 if (!LookupCtx && isDependentScopeSpecifier(SS)) {
3674 Diag(SS.getBeginLoc(), diag::err_typename_missing_template)
3675 << SS.getScopeRep() << TemplateII->getName();
3676 // Recover as if 'typename' were specified.
3677 // FIXME: This is not quite correct recovery as we don't transform SS
3678 // into the corresponding dependent form (and we don't diagnose missing
3679 // 'template' keywords within SS as a result).
3680 return ActOnTypenameType(nullptr, SourceLocation(), SS, TemplateKWLoc,
3681 TemplateD, TemplateII, TemplateIILoc, LAngleLoc,
3682 TemplateArgsIn, RAngleLoc);
3685 // Per C++ [class.qual]p2, if the template-id was an injected-class-name,
3686 // it's not actually allowed to be used as a type in most cases. Because
3687 // we annotate it before we know whether it's valid, we have to check for
3689 auto *LookupRD = dyn_cast_or_null<CXXRecordDecl>(LookupCtx);
3690 if (LookupRD && LookupRD->getIdentifier() == TemplateII) {
3692 TemplateKWLoc.isInvalid()
3693 ? diag::err_out_of_line_qualified_id_type_names_constructor
3694 : diag::ext_out_of_line_qualified_id_type_names_constructor)
3695 << TemplateII << 0 /*injected-class-name used as template name*/
3696 << 1 /*if any keyword was present, it was 'template'*/;
3700 TemplateName Template = TemplateD.get();
3701 if (Template.getAsAssumedTemplateName() &&
3702 resolveAssumedTemplateNameAsType(S, Template, TemplateIILoc))
3705 // Translate the parser's template argument list in our AST format.
3706 TemplateArgumentListInfo TemplateArgs(LAngleLoc, RAngleLoc);
3707 translateTemplateArguments(TemplateArgsIn, TemplateArgs);
3709 if (DependentTemplateName *DTN = Template.getAsDependentTemplateName()) {
3711 = Context.getDependentTemplateSpecializationType(ETK_None,
3712 DTN->getQualifier(),
3713 DTN->getIdentifier(),
3715 // Build type-source information.
3717 DependentTemplateSpecializationTypeLoc SpecTL
3718 = TLB.push<DependentTemplateSpecializationTypeLoc>(T);
3719 SpecTL.setElaboratedKeywordLoc(SourceLocation());
3720 SpecTL.setQualifierLoc(SS.getWithLocInContext(Context));
3721 SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
3722 SpecTL.setTemplateNameLoc(TemplateIILoc);
3723 SpecTL.setLAngleLoc(LAngleLoc);
3724 SpecTL.setRAngleLoc(RAngleLoc);
3725 for (unsigned I = 0, N = SpecTL.getNumArgs(); I != N; ++I)
3726 SpecTL.setArgLocInfo(I, TemplateArgs[I].getLocInfo());
3727 return CreateParsedType(T, TLB.getTypeSourceInfo(Context, T));
3730 QualType Result = CheckTemplateIdType(Template, TemplateIILoc, TemplateArgs);
3731 if (Result.isNull())
3734 // Build type-source information.
3736 TemplateSpecializationTypeLoc SpecTL
3737 = TLB.push<TemplateSpecializationTypeLoc>(Result);
3738 SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
3739 SpecTL.setTemplateNameLoc(TemplateIILoc);
3740 SpecTL.setLAngleLoc(LAngleLoc);
3741 SpecTL.setRAngleLoc(RAngleLoc);
3742 for (unsigned i = 0, e = SpecTL.getNumArgs(); i != e; ++i)
3743 SpecTL.setArgLocInfo(i, TemplateArgs[i].getLocInfo());
3745 // NOTE: avoid constructing an ElaboratedTypeLoc if this is a
3746 // constructor or destructor name (in such a case, the scope specifier
3747 // will be attached to the enclosing Decl or Expr node).
3748 if (SS.isNotEmpty() && !IsCtorOrDtorName) {
3749 // Create an elaborated-type-specifier containing the nested-name-specifier.
3750 Result = Context.getElaboratedType(ETK_None, SS.getScopeRep(), Result);
3751 ElaboratedTypeLoc ElabTL = TLB.push<ElaboratedTypeLoc>(Result);
3752 ElabTL.setElaboratedKeywordLoc(SourceLocation());
3753 ElabTL.setQualifierLoc(SS.getWithLocInContext(Context));
3756 return CreateParsedType(Result, TLB.getTypeSourceInfo(Context, Result));
3759 TypeResult Sema::ActOnTagTemplateIdType(TagUseKind TUK,
3760 TypeSpecifierType TagSpec,
3761 SourceLocation TagLoc,
3763 SourceLocation TemplateKWLoc,
3764 TemplateTy TemplateD,
3765 SourceLocation TemplateLoc,
3766 SourceLocation LAngleLoc,
3767 ASTTemplateArgsPtr TemplateArgsIn,
3768 SourceLocation RAngleLoc) {
3769 TemplateName Template = TemplateD.get();
3771 // Translate the parser's template argument list in our AST format.
3772 TemplateArgumentListInfo TemplateArgs(LAngleLoc, RAngleLoc);
3773 translateTemplateArguments(TemplateArgsIn, TemplateArgs);
3775 // Determine the tag kind
3776 TagTypeKind TagKind = TypeWithKeyword::getTagTypeKindForTypeSpec(TagSpec);
3777 ElaboratedTypeKeyword Keyword
3778 = TypeWithKeyword::getKeywordForTagTypeKind(TagKind);
3780 if (DependentTemplateName *DTN = Template.getAsDependentTemplateName()) {
3781 QualType T = Context.getDependentTemplateSpecializationType(Keyword,
3782 DTN->getQualifier(),
3783 DTN->getIdentifier(),
3786 // Build type-source information.
3788 DependentTemplateSpecializationTypeLoc SpecTL
3789 = TLB.push<DependentTemplateSpecializationTypeLoc>(T);
3790 SpecTL.setElaboratedKeywordLoc(TagLoc);
3791 SpecTL.setQualifierLoc(SS.getWithLocInContext(Context));
3792 SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
3793 SpecTL.setTemplateNameLoc(TemplateLoc);
3794 SpecTL.setLAngleLoc(LAngleLoc);
3795 SpecTL.setRAngleLoc(RAngleLoc);
3796 for (unsigned I = 0, N = SpecTL.getNumArgs(); I != N; ++I)
3797 SpecTL.setArgLocInfo(I, TemplateArgs[I].getLocInfo());
3798 return CreateParsedType(T, TLB.getTypeSourceInfo(Context, T));
3801 if (TypeAliasTemplateDecl *TAT =
3802 dyn_cast_or_null<TypeAliasTemplateDecl>(Template.getAsTemplateDecl())) {
3803 // C++0x [dcl.type.elab]p2:
3804 // If the identifier resolves to a typedef-name or the simple-template-id
3805 // resolves to an alias template specialization, the
3806 // elaborated-type-specifier is ill-formed.
3807 Diag(TemplateLoc, diag::err_tag_reference_non_tag)
3808 << TAT << NTK_TypeAliasTemplate << TagKind;
3809 Diag(TAT->getLocation(), diag::note_declared_at);
3812 QualType Result = CheckTemplateIdType(Template, TemplateLoc, TemplateArgs);
3813 if (Result.isNull())
3814 return TypeResult(true);
3816 // Check the tag kind
3817 if (const RecordType *RT = Result->getAs<RecordType>()) {
3818 RecordDecl *D = RT->getDecl();
3820 IdentifierInfo *Id = D->getIdentifier();
3821 assert(Id && "templated class must have an identifier");
3823 if (!isAcceptableTagRedeclaration(D, TagKind, TUK == TUK_Definition,
3825 Diag(TagLoc, diag::err_use_with_wrong_tag)
3827 << FixItHint::CreateReplacement(SourceRange(TagLoc), D->getKindName());
3828 Diag(D->getLocation(), diag::note_previous_use);
3832 // Provide source-location information for the template specialization.
3834 TemplateSpecializationTypeLoc SpecTL
3835 = TLB.push<TemplateSpecializationTypeLoc>(Result);
3836 SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
3837 SpecTL.setTemplateNameLoc(TemplateLoc);
3838 SpecTL.setLAngleLoc(LAngleLoc);
3839 SpecTL.setRAngleLoc(RAngleLoc);
3840 for (unsigned i = 0, e = SpecTL.getNumArgs(); i != e; ++i)
3841 SpecTL.setArgLocInfo(i, TemplateArgs[i].getLocInfo());
3843 // Construct an elaborated type containing the nested-name-specifier (if any)
3845 Result = Context.getElaboratedType(Keyword, SS.getScopeRep(), Result);
3846 ElaboratedTypeLoc ElabTL = TLB.push<ElaboratedTypeLoc>(Result);
3847 ElabTL.setElaboratedKeywordLoc(TagLoc);
3848 ElabTL.setQualifierLoc(SS.getWithLocInContext(Context));
3849 return CreateParsedType(Result, TLB.getTypeSourceInfo(Context, Result));
3852 static bool CheckTemplateSpecializationScope(Sema &S, NamedDecl *Specialized,
3853 NamedDecl *PrevDecl,
3855 bool IsPartialSpecialization);
3857 static TemplateSpecializationKind getTemplateSpecializationKind(Decl *D);
3859 static bool isTemplateArgumentTemplateParameter(
3860 const TemplateArgument &Arg, unsigned Depth, unsigned Index) {
3861 switch (Arg.getKind()) {
3862 case TemplateArgument::Null:
3863 case TemplateArgument::NullPtr:
3864 case TemplateArgument::Integral:
3865 case TemplateArgument::Declaration:
3866 case TemplateArgument::Pack:
3867 case TemplateArgument::TemplateExpansion:
3870 case TemplateArgument::Type: {
3871 QualType Type = Arg.getAsType();
3872 const TemplateTypeParmType *TPT =
3873 Arg.getAsType()->getAs<TemplateTypeParmType>();
3874 return TPT && !Type.hasQualifiers() &&
3875 TPT->getDepth() == Depth && TPT->getIndex() == Index;
3878 case TemplateArgument::Expression: {
3879 DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Arg.getAsExpr());
3880 if (!DRE || !DRE->getDecl())
3882 const NonTypeTemplateParmDecl *NTTP =
3883 dyn_cast<NonTypeTemplateParmDecl>(DRE->getDecl());
3884 return NTTP && NTTP->getDepth() == Depth && NTTP->getIndex() == Index;
3887 case TemplateArgument::Template:
3888 const TemplateTemplateParmDecl *TTP =
3889 dyn_cast_or_null<TemplateTemplateParmDecl>(
3890 Arg.getAsTemplateOrTemplatePattern().getAsTemplateDecl());
3891 return TTP && TTP->getDepth() == Depth && TTP->getIndex() == Index;
3893 llvm_unreachable("unexpected kind of template argument");
3896 static bool isSameAsPrimaryTemplate(TemplateParameterList *Params,
3897 ArrayRef<TemplateArgument> Args) {
3898 if (Params->size() != Args.size())
3901 unsigned Depth = Params->getDepth();
3903 for (unsigned I = 0, N = Args.size(); I != N; ++I) {
3904 TemplateArgument Arg = Args[I];
3906 // If the parameter is a pack expansion, the argument must be a pack
3907 // whose only element is a pack expansion.
3908 if (Params->getParam(I)->isParameterPack()) {
3909 if (Arg.getKind() != TemplateArgument::Pack || Arg.pack_size() != 1 ||
3910 !Arg.pack_begin()->isPackExpansion())
3912 Arg = Arg.pack_begin()->getPackExpansionPattern();
3915 if (!isTemplateArgumentTemplateParameter(Arg, Depth, I))
3922 template<typename PartialSpecDecl>
3923 static void checkMoreSpecializedThanPrimary(Sema &S, PartialSpecDecl *Partial) {
3924 if (Partial->getDeclContext()->isDependentContext())
3927 // FIXME: Get the TDK from deduction in order to provide better diagnostics
3928 // for non-substitution-failure issues?
3929 TemplateDeductionInfo Info(Partial->getLocation());
3930 if (S.isMoreSpecializedThanPrimary(Partial, Info))
3933 auto *Template = Partial->getSpecializedTemplate();
3934 S.Diag(Partial->getLocation(),
3935 diag::ext_partial_spec_not_more_specialized_than_primary)
3936 << isa<VarTemplateDecl>(Template);
3938 if (Info.hasSFINAEDiagnostic()) {
3939 PartialDiagnosticAt Diag = {SourceLocation(),
3940 PartialDiagnostic::NullDiagnostic()};
3941 Info.takeSFINAEDiagnostic(Diag);
3942 SmallString<128> SFINAEArgString;
3943 Diag.second.EmitToString(S.getDiagnostics(), SFINAEArgString);
3945 diag::note_partial_spec_not_more_specialized_than_primary)
3949 S.Diag(Template->getLocation(), diag::note_template_decl_here);
3950 SmallVector<const Expr *, 3> PartialAC, TemplateAC;
3951 Template->getAssociatedConstraints(TemplateAC);
3952 Partial->getAssociatedConstraints(PartialAC);
3953 S.MaybeEmitAmbiguousAtomicConstraintsDiagnostic(Partial, PartialAC, Template,
3958 noteNonDeducibleParameters(Sema &S, TemplateParameterList *TemplateParams,
3959 const llvm::SmallBitVector &DeducibleParams) {
3960 for (unsigned I = 0, N = DeducibleParams.size(); I != N; ++I) {
3961 if (!DeducibleParams[I]) {
3962 NamedDecl *Param = TemplateParams->getParam(I);
3963 if (Param->getDeclName())
3964 S.Diag(Param->getLocation(), diag::note_non_deducible_parameter)
3965 << Param->getDeclName();
3967 S.Diag(Param->getLocation(), diag::note_non_deducible_parameter)
3974 template<typename PartialSpecDecl>
3975 static void checkTemplatePartialSpecialization(Sema &S,
3976 PartialSpecDecl *Partial) {
3977 // C++1z [temp.class.spec]p8: (DR1495)
3978 // - The specialization shall be more specialized than the primary
3979 // template (14.5.5.2).
3980 checkMoreSpecializedThanPrimary(S, Partial);
3982 // C++ [temp.class.spec]p8: (DR1315)
3983 // - Each template-parameter shall appear at least once in the
3984 // template-id outside a non-deduced context.
3985 // C++1z [temp.class.spec.match]p3 (P0127R2)
3986 // If the template arguments of a partial specialization cannot be
3987 // deduced because of the structure of its template-parameter-list
3988 // and the template-id, the program is ill-formed.
3989 auto *TemplateParams = Partial->getTemplateParameters();
3990 llvm::SmallBitVector DeducibleParams(TemplateParams->size());
3991 S.MarkUsedTemplateParameters(Partial->getTemplateArgs(), true,
3992 TemplateParams->getDepth(), DeducibleParams);
3994 if (!DeducibleParams.all()) {
3995 unsigned NumNonDeducible = DeducibleParams.size() - DeducibleParams.count();
3996 S.Diag(Partial->getLocation(), diag::ext_partial_specs_not_deducible)
3997 << isa<VarTemplatePartialSpecializationDecl>(Partial)
3998 << (NumNonDeducible > 1)
3999 << SourceRange(Partial->getLocation(),
4000 Partial->getTemplateArgsAsWritten()->RAngleLoc);
4001 noteNonDeducibleParameters(S, TemplateParams, DeducibleParams);
4005 void Sema::CheckTemplatePartialSpecialization(
4006 ClassTemplatePartialSpecializationDecl *Partial) {
4007 checkTemplatePartialSpecialization(*this, Partial);
4010 void Sema::CheckTemplatePartialSpecialization(
4011 VarTemplatePartialSpecializationDecl *Partial) {
4012 checkTemplatePartialSpecialization(*this, Partial);
4015 void Sema::CheckDeductionGuideTemplate(FunctionTemplateDecl *TD) {
4016 // C++1z [temp.param]p11:
4017 // A template parameter of a deduction guide template that does not have a
4018 // default-argument shall be deducible from the parameter-type-list of the
4019 // deduction guide template.
4020 auto *TemplateParams = TD->getTemplateParameters();
4021 llvm::SmallBitVector DeducibleParams(TemplateParams->size());
4022 MarkDeducedTemplateParameters(TD, DeducibleParams);
4023 for (unsigned I = 0; I != TemplateParams->size(); ++I) {
4024 // A parameter pack is deducible (to an empty pack).
4025 auto *Param = TemplateParams->getParam(I);
4026 if (Param->isParameterPack() || hasVisibleDefaultArgument(Param))
4027 DeducibleParams[I] = true;
4030 if (!DeducibleParams.all()) {
4031 unsigned NumNonDeducible = DeducibleParams.size() - DeducibleParams.count();
4032 Diag(TD->getLocation(), diag::err_deduction_guide_template_not_deducible)
4033 << (NumNonDeducible > 1);
4034 noteNonDeducibleParameters(*this, TemplateParams, DeducibleParams);
4038 DeclResult Sema::ActOnVarTemplateSpecialization(
4039 Scope *S, Declarator &D, TypeSourceInfo *DI, SourceLocation TemplateKWLoc,
4040 TemplateParameterList *TemplateParams, StorageClass SC,
4041 bool IsPartialSpecialization) {
4042 // D must be variable template id.
4043 assert(D.getName().getKind() == UnqualifiedIdKind::IK_TemplateId &&
4044 "Variable template specialization is declared with a template it.");
4046 TemplateIdAnnotation *TemplateId = D.getName().TemplateId;
4047 TemplateArgumentListInfo TemplateArgs =
4048 makeTemplateArgumentListInfo(*this, *TemplateId);
4049 SourceLocation TemplateNameLoc = D.getIdentifierLoc();
4050 SourceLocation LAngleLoc = TemplateId->LAngleLoc;
4051 SourceLocation RAngleLoc = TemplateId->RAngleLoc;
4053 TemplateName Name = TemplateId->Template.get();
4055 // The template-id must name a variable template.
4056 VarTemplateDecl *VarTemplate =
4057 dyn_cast_or_null<VarTemplateDecl>(Name.getAsTemplateDecl());
4059 NamedDecl *FnTemplate;
4060 if (auto *OTS = Name.getAsOverloadedTemplate())
4061 FnTemplate = *OTS->begin();
4063 FnTemplate = dyn_cast_or_null<FunctionTemplateDecl>(Name.getAsTemplateDecl());
4065 return Diag(D.getIdentifierLoc(), diag::err_var_spec_no_template_but_method)
4066 << FnTemplate->getDeclName();
4067 return Diag(D.getIdentifierLoc(), diag::err_var_spec_no_template)
4068 << IsPartialSpecialization;
4071 // Check for unexpanded parameter packs in any of the template arguments.
4072 for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I)
4073 if (DiagnoseUnexpandedParameterPack(TemplateArgs[I],
4074 UPPC_PartialSpecialization))
4077 // Check that the template argument list is well-formed for this
4079 SmallVector<TemplateArgument, 4> Converted;
4080 if (CheckTemplateArgumentList(VarTemplate, TemplateNameLoc, TemplateArgs,
4082 /*UpdateArgsWithConversion=*/true))
4085 // Find the variable template (partial) specialization declaration that
4086 // corresponds to these arguments.
4087 if (IsPartialSpecialization) {
4088 if (CheckTemplatePartialSpecializationArgs(TemplateNameLoc, VarTemplate,
4089 TemplateArgs.size(), Converted))
4092 // FIXME: Move these checks to CheckTemplatePartialSpecializationArgs so we
4093 // also do them during instantiation.
4094 bool InstantiationDependent;
4095 if (!Name.isDependent() &&
4096 !TemplateSpecializationType::anyDependentTemplateArguments(
4097 TemplateArgs.arguments(),
4098 InstantiationDependent)) {
4099 Diag(TemplateNameLoc, diag::err_partial_spec_fully_specialized)
4100 << VarTemplate->getDeclName();
4101 IsPartialSpecialization = false;
4104 if (isSameAsPrimaryTemplate(VarTemplate->getTemplateParameters(),
4106 (!Context.getLangOpts().CPlusPlus2a ||
4107 !TemplateParams->hasAssociatedConstraints())) {
4108 // C++ [temp.class.spec]p9b3:
4110 // -- The argument list of the specialization shall not be identical
4111 // to the implicit argument list of the primary template.
4112 Diag(TemplateNameLoc, diag::err_partial_spec_args_match_primary_template)
4113 << /*variable template*/ 1
4114 << /*is definition*/(SC != SC_Extern && !CurContext->isRecord())
4115 << FixItHint::CreateRemoval(SourceRange(LAngleLoc, RAngleLoc));
4116 // FIXME: Recover from this by treating the declaration as a redeclaration
4117 // of the primary template.
4122 void *InsertPos = nullptr;
4123 VarTemplateSpecializationDecl *PrevDecl = nullptr;
4125 if (IsPartialSpecialization)
4126 PrevDecl = VarTemplate->findPartialSpecialization(Converted, TemplateParams,
4129 PrevDecl = VarTemplate->findSpecialization(Converted, InsertPos);
4131 VarTemplateSpecializationDecl *Specialization = nullptr;
4133 // Check whether we can declare a variable template specialization in
4134 // the current scope.
4135 if (CheckTemplateSpecializationScope(*this, VarTemplate, PrevDecl,
4137 IsPartialSpecialization))
4140 if (PrevDecl && PrevDecl->getSpecializationKind() == TSK_Undeclared) {
4141 // Since the only prior variable template specialization with these
4142 // arguments was referenced but not declared, reuse that
4143 // declaration node as our own, updating its source location and
4144 // the list of outer template parameters to reflect our new declaration.
4145 Specialization = PrevDecl;
4146 Specialization->setLocation(TemplateNameLoc);
4148 } else if (IsPartialSpecialization) {
4149 // Create a new class template partial specialization declaration node.
4150 VarTemplatePartialSpecializationDecl *PrevPartial =
4151 cast_or_null<VarTemplatePartialSpecializationDecl>(PrevDecl);
4152 VarTemplatePartialSpecializationDecl *Partial =
4153 VarTemplatePartialSpecializationDecl::Create(
4154 Context, VarTemplate->getDeclContext(), TemplateKWLoc,
4155 TemplateNameLoc, TemplateParams, VarTemplate, DI->getType(), DI, SC,
4156 Converted, TemplateArgs);
4159 VarTemplate->AddPartialSpecialization(Partial, InsertPos);
4160 Specialization = Partial;
4162 // If we are providing an explicit specialization of a member variable
4163 // template specialization, make a note of that.
4164 if (PrevPartial && PrevPartial->getInstantiatedFromMember())
4165 PrevPartial->setMemberSpecialization();
4167 CheckTemplatePartialSpecialization(Partial);
4169 // Create a new class template specialization declaration node for
4170 // this explicit specialization or friend declaration.
4171 Specialization = VarTemplateSpecializationDecl::Create(
4172 Context, VarTemplate->getDeclContext(), TemplateKWLoc, TemplateNameLoc,
4173 VarTemplate, DI->getType(), DI, SC, Converted);
4174 Specialization->setTemplateArgsInfo(TemplateArgs);
4177 VarTemplate->AddSpecialization(Specialization, InsertPos);
4180 // C++ [temp.expl.spec]p6:
4181 // If a template, a member template or the member of a class template is
4182 // explicitly specialized then that specialization shall be declared
4183 // before the first use of that specialization that would cause an implicit
4184 // instantiation to take place, in every translation unit in which such a
4185 // use occurs; no diagnostic is required.
4186 if (PrevDecl && PrevDecl->getPointOfInstantiation().isValid()) {
4188 for (Decl *Prev = PrevDecl; Prev; Prev = Prev->getPreviousDecl()) {
4189 // Is there any previous explicit specialization declaration?
4190 if (getTemplateSpecializationKind(Prev) == TSK_ExplicitSpecialization) {
4197 SourceRange Range(TemplateNameLoc, RAngleLoc);
4198 Diag(TemplateNameLoc, diag::err_specialization_after_instantiation)
4201 Diag(PrevDecl->getPointOfInstantiation(),
4202 diag::note_instantiation_required_here)
4203 << (PrevDecl->getTemplateSpecializationKind() !=
4204 TSK_ImplicitInstantiation);
4209 Specialization->setTemplateKeywordLoc(TemplateKWLoc);
4210 Specialization->setLexicalDeclContext(CurContext);
4212 // Add the specialization into its lexical context, so that it can
4213 // be seen when iterating through the list of declarations in that
4214 // context. However, specializations are not found by name lookup.
4215 CurContext->addDecl(Specialization);
4217 // Note that this is an explicit specialization.
4218 Specialization->setSpecializationKind(TSK_ExplicitSpecialization);
4221 // Check that this isn't a redefinition of this specialization,
4222 // merging with previous declarations.
4223 LookupResult PrevSpec(*this, GetNameForDeclarator(D), LookupOrdinaryName,
4224 forRedeclarationInCurContext());
4225 PrevSpec.addDecl(PrevDecl);
4226 D.setRedeclaration(CheckVariableDeclaration(Specialization, PrevSpec));
4227 } else if (Specialization->isStaticDataMember() &&
4228 Specialization->isOutOfLine()) {
4229 Specialization->setAccess(VarTemplate->getAccess());
4232 return Specialization;
4236 /// A partial specialization whose template arguments have matched
4237 /// a given template-id.
4238 struct PartialSpecMatchResult {
4239 VarTemplatePartialSpecializationDecl *Partial;
4240 TemplateArgumentList *Args;
4242 } // end anonymous namespace
4245 Sema::CheckVarTemplateId(VarTemplateDecl *Template, SourceLocation TemplateLoc,
4246 SourceLocation TemplateNameLoc,
4247 const TemplateArgumentListInfo &TemplateArgs) {
4248 assert(Template && "A variable template id without template?");
4250 // Check that the template argument list is well-formed for this template.
4251 SmallVector<TemplateArgument, 4> Converted;
4252 if (CheckTemplateArgumentList(
4253 Template, TemplateNameLoc,
4254 const_cast<TemplateArgumentListInfo &>(TemplateArgs), false,
4255 Converted, /*UpdateArgsWithConversion=*/true))
4258 // Find the variable template specialization declaration that
4259 // corresponds to these arguments.
4260 void *InsertPos = nullptr;
4261 if (VarTemplateSpecializationDecl *Spec = Template->findSpecialization(
4262 Converted, InsertPos)) {
4263 checkSpecializationVisibility(TemplateNameLoc, Spec);
4264 // If we already have a variable template specialization, return it.
4268 // This is the first time we have referenced this variable template
4269 // specialization. Create the canonical declaration and add it to
4270 // the set of specializations, based on the closest partial specialization
4271 // that it represents. That is,
4272 VarDecl *InstantiationPattern = Template->getTemplatedDecl();
4273 TemplateArgumentList TemplateArgList(TemplateArgumentList::OnStack,
4275 TemplateArgumentList *InstantiationArgs = &TemplateArgList;
4276 bool AmbiguousPartialSpec = false;
4277 typedef PartialSpecMatchResult MatchResult;
4278 SmallVector<MatchResult, 4> Matched;
4279 SourceLocation PointOfInstantiation = TemplateNameLoc;
4280 TemplateSpecCandidateSet FailedCandidates(PointOfInstantiation,
4281 /*ForTakingAddress=*/false);
4283 // 1. Attempt to find the closest partial specialization that this
4284 // specializes, if any.
4285 // If any of the template arguments is dependent, then this is probably
4286 // a placeholder for an incomplete declarative context; which must be
4287 // complete by instantiation time. Thus, do not search through the partial
4288 // specializations yet.
4289 // TODO: Unify with InstantiateClassTemplateSpecialization()?
4290 // Perhaps better after unification of DeduceTemplateArguments() and
4291 // getMoreSpecializedPartialSpecialization().
4292 bool InstantiationDependent = false;
4293 if (!TemplateSpecializationType::anyDependentTemplateArguments(
4294 TemplateArgs, InstantiationDependent)) {
4296 SmallVector<VarTemplatePartialSpecializationDecl *, 4> PartialSpecs;
4297 Template->getPartialSpecializations(PartialSpecs);
4299 for (unsigned I = 0, N = PartialSpecs.size(); I != N; ++I) {
4300 VarTemplatePartialSpecializationDecl *Partial = PartialSpecs[I];
4301 TemplateDeductionInfo Info(FailedCandidates.getLocation());
4303 if (TemplateDeductionResult Result =
4304 DeduceTemplateArguments(Partial, TemplateArgList, Info)) {
4305 // Store the failed-deduction information for use in diagnostics, later.
4306 // TODO: Actually use the failed-deduction info?
4307 FailedCandidates.addCandidate().set(
4308 DeclAccessPair::make(Template, AS_public), Partial,
4309 MakeDeductionFailureInfo(Context, Result, Info));
4312 Matched.push_back(PartialSpecMatchResult());
4313 Matched.back().Partial = Partial;
4314 Matched.back().Args = Info.take();
4318 if (Matched.size() >= 1) {
4319 SmallVector<MatchResult, 4>::iterator Best = Matched.begin();
4320 if (Matched.size() == 1) {
4321 // -- If exactly one matching specialization is found, the
4322 // instantiation is generated from that specialization.
4323 // We don't need to do anything for this.
4325 // -- If more than one matching specialization is found, the
4326 // partial order rules (14.5.4.2) are used to determine
4327 // whether one of the specializations is more specialized
4328 // than the others. If none of the specializations is more
4329 // specialized than all of the other matching
4330 // specializations, then the use of the variable template is
4331 // ambiguous and the program is ill-formed.
4332 for (SmallVector<MatchResult, 4>::iterator P = Best + 1,
4333 PEnd = Matched.end();
4335 if (getMoreSpecializedPartialSpecialization(P->Partial, Best->Partial,
4336 PointOfInstantiation) ==
4341 // Determine if the best partial specialization is more specialized than
4343 for (SmallVector<MatchResult, 4>::iterator P = Matched.begin(),
4344 PEnd = Matched.end();
4346 if (P != Best && getMoreSpecializedPartialSpecialization(
4347 P->Partial, Best->Partial,
4348 PointOfInstantiation) != Best->Partial) {
4349 AmbiguousPartialSpec = true;
4355 // Instantiate using the best variable template partial specialization.
4356 InstantiationPattern = Best->Partial;
4357 InstantiationArgs = Best->Args;
4359 // -- If no match is found, the instantiation is generated
4360 // from the primary template.
4361 // InstantiationPattern = Template->getTemplatedDecl();
4365 // 2. Create the canonical declaration.
4366 // Note that we do not instantiate a definition until we see an odr-use
4367 // in DoMarkVarDeclReferenced().
4368 // FIXME: LateAttrs et al.?
4369 VarTemplateSpecializationDecl *Decl = BuildVarTemplateInstantiation(
4370 Template, InstantiationPattern, *InstantiationArgs, TemplateArgs,
4371 Converted, TemplateNameLoc, InsertPos /*, LateAttrs, StartingScope*/);
4375 if (AmbiguousPartialSpec) {
4376 // Partial ordering did not produce a clear winner. Complain.
4377 Decl->setInvalidDecl();
4378 Diag(PointOfInstantiation, diag::err_partial_spec_ordering_ambiguous)
4381 // Print the matching partial specializations.
4382 for (MatchResult P : Matched)
4383 Diag(P.Partial->getLocation(), diag::note_partial_spec_match)
4384 << getTemplateArgumentBindingsText(P.Partial->getTemplateParameters(),
4389 if (VarTemplatePartialSpecializationDecl *D =
4390 dyn_cast<VarTemplatePartialSpecializationDecl>(InstantiationPattern))
4391 Decl->setInstantiationOf(D, InstantiationArgs);
4393 checkSpecializationVisibility(TemplateNameLoc, Decl);
4395 assert(Decl && "No variable template specialization?");
4400 Sema::CheckVarTemplateId(const CXXScopeSpec &SS,
4401 const DeclarationNameInfo &NameInfo,
4402 VarTemplateDecl *Template, SourceLocation TemplateLoc,
4403 const TemplateArgumentListInfo *TemplateArgs) {
4405 DeclResult Decl = CheckVarTemplateId(Template, TemplateLoc, NameInfo.getLoc(),
4407 if (Decl.isInvalid())
4410 VarDecl *Var = cast<VarDecl>(Decl.get());
4411 if (!Var->getTemplateSpecializationKind())
4412 Var->setTemplateSpecializationKind(TSK_ImplicitInstantiation,
4415 // Build an ordinary singleton decl ref.
4416 return BuildDeclarationNameExpr(SS, NameInfo, Var,
4417 /*FoundD=*/nullptr, TemplateArgs);
4420 void Sema::diagnoseMissingTemplateArguments(TemplateName Name,
4421 SourceLocation Loc) {
4422 Diag(Loc, diag::err_template_missing_args)
4423 << (int)getTemplateNameKindForDiagnostics(Name) << Name;
4424 if (TemplateDecl *TD = Name.getAsTemplateDecl()) {
4425 Diag(TD->getLocation(), diag::note_template_decl_here)
4426 << TD->getTemplateParameters()->getSourceRange();
4431 Sema::CheckConceptTemplateId(const CXXScopeSpec &SS,
4432 SourceLocation TemplateKWLoc,
4433 const DeclarationNameInfo &ConceptNameInfo,
4434 NamedDecl *FoundDecl,
4435 ConceptDecl *NamedConcept,
4436 const TemplateArgumentListInfo *TemplateArgs) {
4437 assert(NamedConcept && "A concept template id without a template?");
4439 llvm::SmallVector<TemplateArgument, 4> Converted;
4440 if (CheckTemplateArgumentList(NamedConcept, ConceptNameInfo.getLoc(),
4441 const_cast<TemplateArgumentListInfo&>(*TemplateArgs),
4442 /*PartialTemplateArgs=*/false, Converted,
4443 /*UpdateArgsWithConversion=*/false))
4446 ConstraintSatisfaction Satisfaction;
4447 bool AreArgsDependent = false;
4448 for (TemplateArgument &Arg : Converted) {
4449 if (Arg.isDependent()) {
4450 AreArgsDependent = true;
4454 if (!AreArgsDependent &&
4455 CheckConstraintSatisfaction(NamedConcept,
4456 {NamedConcept->getConstraintExpr()},
4458 SourceRange(SS.isSet() ? SS.getBeginLoc() :
4459 ConceptNameInfo.getLoc(),
4460 TemplateArgs->getRAngleLoc()),
4464 return ConceptSpecializationExpr::Create(Context,
4465 SS.isSet() ? SS.getWithLocInContext(Context) : NestedNameSpecifierLoc{},
4466 TemplateKWLoc, ConceptNameInfo, FoundDecl, NamedConcept,
4467 ASTTemplateArgumentListInfo::Create(Context, *TemplateArgs), Converted,
4468 AreArgsDependent ? nullptr : &Satisfaction);
4471 ExprResult Sema::BuildTemplateIdExpr(const CXXScopeSpec &SS,
4472 SourceLocation TemplateKWLoc,
4475 const TemplateArgumentListInfo *TemplateArgs) {
4476 // FIXME: Can we do any checking at this point? I guess we could check the
4477 // template arguments that we have against the template name, if the template
4478 // name refers to a single template. That's not a terribly common case,
4480 // foo<int> could identify a single function unambiguously
4481 // This approach does NOT work, since f<int>(1);
4482 // gets resolved prior to resorting to overload resolution
4483 // i.e., template<class T> void f(double);
4484 // vs template<class T, class U> void f(U);
4486 // These should be filtered out by our callers.
4487 assert(!R.isAmbiguous() && "ambiguous lookup when building templateid");
4489 // Non-function templates require a template argument list.
4490 if (auto *TD = R.getAsSingle<TemplateDecl>()) {
4491 if (!TemplateArgs && !isa<FunctionTemplateDecl>(TD)) {
4492 diagnoseMissingTemplateArguments(TemplateName(TD), R.getNameLoc());
4497 auto AnyDependentArguments = [&]() -> bool {
4498 bool InstantiationDependent;
4499 return TemplateArgs &&
4500 TemplateSpecializationType::anyDependentTemplateArguments(
4501 *TemplateArgs, InstantiationDependent);
4504 // In C++1y, check variable template ids.
4505 if (R.getAsSingle<VarTemplateDecl>() && !AnyDependentArguments()) {
4506 return CheckVarTemplateId(SS, R.getLookupNameInfo(),
4507 R.getAsSingle<VarTemplateDecl>(),
4508 TemplateKWLoc, TemplateArgs);
4511 if (R.getAsSingle<ConceptDecl>()) {
4512 return CheckConceptTemplateId(SS, TemplateKWLoc, R.getLookupNameInfo(),
4514 R.getAsSingle<ConceptDecl>(), TemplateArgs);
4517 // We don't want lookup warnings at this point.
4518 R.suppressDiagnostics();
4520 UnresolvedLookupExpr *ULE
4521 = UnresolvedLookupExpr::Create(Context, R.getNamingClass(),
4522 SS.getWithLocInContext(Context),
4524 R.getLookupNameInfo(),
4525 RequiresADL, TemplateArgs,
4526 R.begin(), R.end());
4531 // We actually only call this from template instantiation.
4533 Sema::BuildQualifiedTemplateIdExpr(CXXScopeSpec &SS,
4534 SourceLocation TemplateKWLoc,
4535 const DeclarationNameInfo &NameInfo,
4536 const TemplateArgumentListInfo *TemplateArgs) {
4538 assert(TemplateArgs || TemplateKWLoc.isValid());
4540 if (!(DC = computeDeclContext(SS, false)) ||
4541 DC->isDependentContext() ||
4542 RequireCompleteDeclContext(SS, DC))
4543 return BuildDependentDeclRefExpr(SS, TemplateKWLoc, NameInfo, TemplateArgs);
4545 bool MemberOfUnknownSpecialization;
4546 LookupResult R(*this, NameInfo, LookupOrdinaryName);
4547 if (LookupTemplateName(R, (Scope *)nullptr, SS, QualType(),
4548 /*Entering*/false, MemberOfUnknownSpecialization,
4552 if (R.isAmbiguous())
4556 Diag(NameInfo.getLoc(), diag::err_no_member)
4557 << NameInfo.getName() << DC << SS.getRange();
4561 if (ClassTemplateDecl *Temp = R.getAsSingle<ClassTemplateDecl>()) {
4562 Diag(NameInfo.getLoc(), diag::err_template_kw_refers_to_class_template)
4564 << NameInfo.getName().getAsString() << SS.getRange();
4565 Diag(Temp->getLocation(), diag::note_referenced_class_template);
4569 return BuildTemplateIdExpr(SS, TemplateKWLoc, R, /*ADL*/ false, TemplateArgs);
4572 /// Form a dependent template name.
4574 /// This action forms a dependent template name given the template
4575 /// name and its (presumably dependent) scope specifier. For
4576 /// example, given "MetaFun::template apply", the scope specifier \p
4577 /// SS will be "MetaFun::", \p TemplateKWLoc contains the location
4578 /// of the "template" keyword, and "apply" is the \p Name.
4579 TemplateNameKind Sema::ActOnDependentTemplateName(Scope *S,
4581 SourceLocation TemplateKWLoc,
4582 const UnqualifiedId &Name,
4583 ParsedType ObjectType,
4584 bool EnteringContext,
4586 bool AllowInjectedClassName) {
4587 if (TemplateKWLoc.isValid() && S && !S->getTemplateParamParent())
4589 getLangOpts().CPlusPlus11 ?
4590 diag::warn_cxx98_compat_template_outside_of_template :
4591 diag::ext_template_outside_of_template)
4592 << FixItHint::CreateRemoval(TemplateKWLoc);
4594 DeclContext *LookupCtx = nullptr;
4596 LookupCtx = computeDeclContext(SS, EnteringContext);
4597 if (!LookupCtx && ObjectType)
4598 LookupCtx = computeDeclContext(ObjectType.get());
4600 // C++0x [temp.names]p5:
4601 // If a name prefixed by the keyword template is not the name of
4602 // a template, the program is ill-formed. [Note: the keyword
4603 // template may not be applied to non-template members of class
4604 // templates. -end note ] [ Note: as is the case with the
4605 // typename prefix, the template prefix is allowed in cases
4606 // where it is not strictly necessary; i.e., when the
4607 // nested-name-specifier or the expression on the left of the ->
4608 // or . is not dependent on a template-parameter, or the use
4609 // does not appear in the scope of a template. -end note]
4611 // Note: C++03 was more strict here, because it banned the use of
4612 // the "template" keyword prior to a template-name that was not a
4613 // dependent name. C++ DR468 relaxed this requirement (the
4614 // "template" keyword is now permitted). We follow the C++0x
4615 // rules, even in C++03 mode with a warning, retroactively applying the DR.
4616 bool MemberOfUnknownSpecialization;
4617 TemplateNameKind TNK = isTemplateName(S, SS, TemplateKWLoc.isValid(), Name,
4618 ObjectType, EnteringContext, Result,
4619 MemberOfUnknownSpecialization);
4620 if (TNK == TNK_Non_template && MemberOfUnknownSpecialization) {
4621 // This is a dependent template. Handle it below.
4622 } else if (TNK == TNK_Non_template) {
4623 // Do the lookup again to determine if this is a "nothing found" case or
4624 // a "not a template" case. FIXME: Refactor isTemplateName so we don't
4626 DeclarationNameInfo DNI = GetNameFromUnqualifiedId(Name);
4627 LookupResult R(*this, DNI.getName(), Name.getBeginLoc(),
4628 LookupOrdinaryName);
4630 if (!LookupTemplateName(R, S, SS, ObjectType.get(), EnteringContext,
4631 MOUS, TemplateKWLoc) && !R.isAmbiguous())
4632 Diag(Name.getBeginLoc(), diag::err_no_member)
4633 << DNI.getName() << LookupCtx << SS.getRange();
4634 return TNK_Non_template;
4636 // We found something; return it.
4637 auto *LookupRD = dyn_cast<CXXRecordDecl>(LookupCtx);
4638 if (!AllowInjectedClassName && SS.isSet() && LookupRD &&
4639 Name.getKind() == UnqualifiedIdKind::IK_Identifier &&
4640 Name.Identifier && LookupRD->getIdentifier() == Name.Identifier) {
4641 // C++14 [class.qual]p2:
4642 // In a lookup in which function names are not ignored and the
4643 // nested-name-specifier nominates a class C, if the name specified
4644 // [...] is the injected-class-name of C, [...] the name is instead
4645 // considered to name the constructor
4647 // We don't get here if naming the constructor would be valid, so we
4648 // just reject immediately and recover by treating the
4649 // injected-class-name as naming the template.
4650 Diag(Name.getBeginLoc(),
4651 diag::ext_out_of_line_qualified_id_type_names_constructor)
4653 << 0 /*injected-class-name used as template name*/
4654 << 1 /*'template' keyword was used*/;
4660 NestedNameSpecifier *Qualifier = SS.getScopeRep();
4662 switch (Name.getKind()) {
4663 case UnqualifiedIdKind::IK_Identifier:
4664 Result = TemplateTy::make(Context.getDependentTemplateName(Qualifier,
4666 return TNK_Dependent_template_name;
4668 case UnqualifiedIdKind::IK_OperatorFunctionId:
4669 Result = TemplateTy::make(Context.getDependentTemplateName(Qualifier,
4670 Name.OperatorFunctionId.Operator));
4671 return TNK_Function_template;
4673 case UnqualifiedIdKind::IK_LiteralOperatorId:
4674 llvm_unreachable("literal operator id cannot have a dependent scope");
4680 Diag(Name.getBeginLoc(), diag::err_template_kw_refers_to_non_template)
4681 << GetNameFromUnqualifiedId(Name).getName() << Name.getSourceRange()
4683 return TNK_Non_template;
4686 bool Sema::CheckTemplateTypeArgument(TemplateTypeParmDecl *Param,
4687 TemplateArgumentLoc &AL,
4688 SmallVectorImpl<TemplateArgument> &Converted) {
4689 const TemplateArgument &Arg = AL.getArgument();
4691 TypeSourceInfo *TSI = nullptr;
4693 // Check template type parameter.
4694 switch(Arg.getKind()) {
4695 case TemplateArgument::Type:
4696 // C++ [temp.arg.type]p1:
4697 // A template-argument for a template-parameter which is a
4698 // type shall be a type-id.
4699 ArgType = Arg.getAsType();
4700 TSI = AL.getTypeSourceInfo();
4702 case TemplateArgument::Template:
4703 case TemplateArgument::TemplateExpansion: {
4704 // We have a template type parameter but the template argument
4705 // is a template without any arguments.
4706 SourceRange SR = AL.getSourceRange();
4707 TemplateName Name = Arg.getAsTemplateOrTemplatePattern();
4708 diagnoseMissingTemplateArguments(Name, SR.getEnd());
4711 case TemplateArgument::Expression: {
4712 // We have a template type parameter but the template argument is an
4713 // expression; see if maybe it is missing the "typename" keyword.
4715 DeclarationNameInfo NameInfo;
4717 if (DeclRefExpr *ArgExpr = dyn_cast<DeclRefExpr>(Arg.getAsExpr())) {
4718 SS.Adopt(ArgExpr->getQualifierLoc());
4719 NameInfo = ArgExpr->getNameInfo();
4720 } else if (DependentScopeDeclRefExpr *ArgExpr =
4721 dyn_cast<DependentScopeDeclRefExpr>(Arg.getAsExpr())) {
4722 SS.Adopt(ArgExpr->getQualifierLoc());
4723 NameInfo = ArgExpr->getNameInfo();
4724 } else if (CXXDependentScopeMemberExpr *ArgExpr =
4725 dyn_cast<CXXDependentScopeMemberExpr>(Arg.getAsExpr())) {
4726 if (ArgExpr->isImplicitAccess()) {
4727 SS.Adopt(ArgExpr->getQualifierLoc());
4728 NameInfo = ArgExpr->getMemberNameInfo();
4732 if (auto *II = NameInfo.getName().getAsIdentifierInfo()) {
4733 LookupResult Result(*this, NameInfo, LookupOrdinaryName);
4734 LookupParsedName(Result, CurScope, &SS);
4736 if (Result.getAsSingle<TypeDecl>() ||
4737 Result.getResultKind() ==
4738 LookupResult::NotFoundInCurrentInstantiation) {
4739 // Suggest that the user add 'typename' before the NNS.
4740 SourceLocation Loc = AL.getSourceRange().getBegin();
4741 Diag(Loc, getLangOpts().MSVCCompat
4742 ? diag::ext_ms_template_type_arg_missing_typename
4743 : diag::err_template_arg_must_be_type_suggest)
4744 << FixItHint::CreateInsertion(Loc, "typename ");
4745 Diag(Param->getLocation(), diag::note_template_param_here);
4747 // Recover by synthesizing a type using the location information that we
4750 Context.getDependentNameType(ETK_Typename, SS.getScopeRep(), II);
4752 DependentNameTypeLoc TL = TLB.push<DependentNameTypeLoc>(ArgType);
4753 TL.setElaboratedKeywordLoc(SourceLocation(/*synthesized*/));
4754 TL.setQualifierLoc(SS.getWithLocInContext(Context));
4755 TL.setNameLoc(NameInfo.getLoc());
4756 TSI = TLB.getTypeSourceInfo(Context, ArgType);
4758 // Overwrite our input TemplateArgumentLoc so that we can recover
4760 AL = TemplateArgumentLoc(TemplateArgument(ArgType),
4761 TemplateArgumentLocInfo(TSI));
4770 // We have a template type parameter but the template argument
4772 SourceRange SR = AL.getSourceRange();
4773 Diag(SR.getBegin(), diag::err_template_arg_must_be_type) << SR;
4774 Diag(Param->getLocation(), diag::note_template_param_here);
4780 if (CheckTemplateArgument(Param, TSI))
4783 // Add the converted template type argument.
4784 ArgType = Context.getCanonicalType(ArgType);
4787 // If an explicitly-specified template argument type is a lifetime type
4788 // with no lifetime qualifier, the __strong lifetime qualifier is inferred.
4789 if (getLangOpts().ObjCAutoRefCount &&
4790 ArgType->isObjCLifetimeType() &&
4791 !ArgType.getObjCLifetime()) {
4793 Qs.setObjCLifetime(Qualifiers::OCL_Strong);
4794 ArgType = Context.getQualifiedType(ArgType, Qs);
4797 Converted.push_back(TemplateArgument(ArgType));
4801 /// Substitute template arguments into the default template argument for
4802 /// the given template type parameter.
4804 /// \param SemaRef the semantic analysis object for which we are performing
4805 /// the substitution.
4807 /// \param Template the template that we are synthesizing template arguments
4810 /// \param TemplateLoc the location of the template name that started the
4811 /// template-id we are checking.
4813 /// \param RAngleLoc the location of the right angle bracket ('>') that
4814 /// terminates the template-id.
4816 /// \param Param the template template parameter whose default we are
4817 /// substituting into.
4819 /// \param Converted the list of template arguments provided for template
4820 /// parameters that precede \p Param in the template parameter list.
4821 /// \returns the substituted template argument, or NULL if an error occurred.
4822 static TypeSourceInfo *
4823 SubstDefaultTemplateArgument(Sema &SemaRef,
4824 TemplateDecl *Template,
4825 SourceLocation TemplateLoc,
4826 SourceLocation RAngleLoc,
4827 TemplateTypeParmDecl *Param,
4828 SmallVectorImpl<TemplateArgument> &Converted) {
4829 TypeSourceInfo *ArgType = Param->getDefaultArgumentInfo();
4831 // If the argument type is dependent, instantiate it now based
4832 // on the previously-computed template arguments.
4833 if (ArgType->getType()->isInstantiationDependentType()) {
4834 Sema::InstantiatingTemplate Inst(SemaRef, TemplateLoc,
4835 Param, Template, Converted,
4836 SourceRange(TemplateLoc, RAngleLoc));
4837 if (Inst.isInvalid())
4840 TemplateArgumentList TemplateArgs(TemplateArgumentList::OnStack, Converted);
4842 // Only substitute for the innermost template argument list.
4843 MultiLevelTemplateArgumentList TemplateArgLists;
4844 TemplateArgLists.addOuterTemplateArguments(&TemplateArgs);
4845 for (unsigned i = 0, e = Param->getDepth(); i != e; ++i)
4846 TemplateArgLists.addOuterTemplateArguments(None);
4848 Sema::ContextRAII SavedContext(SemaRef, Template->getDeclContext());
4850 SemaRef.SubstType(ArgType, TemplateArgLists,
4851 Param->getDefaultArgumentLoc(), Param->getDeclName());
4857 /// Substitute template arguments into the default template argument for
4858 /// the given non-type template parameter.
4860 /// \param SemaRef the semantic analysis object for which we are performing
4861 /// the substitution.
4863 /// \param Template the template that we are synthesizing template arguments
4866 /// \param TemplateLoc the location of the template name that started the
4867 /// template-id we are checking.
4869 /// \param RAngleLoc the location of the right angle bracket ('>') that
4870 /// terminates the template-id.
4872 /// \param Param the non-type template parameter whose default we are
4873 /// substituting into.
4875 /// \param Converted the list of template arguments provided for template
4876 /// parameters that precede \p Param in the template parameter list.
4878 /// \returns the substituted template argument, or NULL if an error occurred.
4880 SubstDefaultTemplateArgument(Sema &SemaRef,
4881 TemplateDecl *Template,
4882 SourceLocation TemplateLoc,
4883 SourceLocation RAngleLoc,
4884 NonTypeTemplateParmDecl *Param,
4885 SmallVectorImpl<TemplateArgument> &Converted) {
4886 Sema::InstantiatingTemplate Inst(SemaRef, TemplateLoc,
4887 Param, Template, Converted,
4888 SourceRange(TemplateLoc, RAngleLoc));
4889 if (Inst.isInvalid())
4892 TemplateArgumentList TemplateArgs(TemplateArgumentList::OnStack, Converted);
4894 // Only substitute for the innermost template argument list.
4895 MultiLevelTemplateArgumentList TemplateArgLists;
4896 TemplateArgLists.addOuterTemplateArguments(&TemplateArgs);
4897 for (unsigned i = 0, e = Param->getDepth(); i != e; ++i)
4898 TemplateArgLists.addOuterTemplateArguments(None);
4900 Sema::ContextRAII SavedContext(SemaRef, Template->getDeclContext());
4901 EnterExpressionEvaluationContext ConstantEvaluated(
4902 SemaRef, Sema::ExpressionEvaluationContext::ConstantEvaluated);
4903 return SemaRef.SubstExpr(Param->getDefaultArgument(), TemplateArgLists);
4906 /// Substitute template arguments into the default template argument for
4907 /// the given template template parameter.
4909 /// \param SemaRef the semantic analysis object for which we are performing
4910 /// the substitution.
4912 /// \param Template the template that we are synthesizing template arguments
4915 /// \param TemplateLoc the location of the template name that started the
4916 /// template-id we are checking.
4918 /// \param RAngleLoc the location of the right angle bracket ('>') that
4919 /// terminates the template-id.
4921 /// \param Param the template template parameter whose default we are
4922 /// substituting into.
4924 /// \param Converted the list of template arguments provided for template
4925 /// parameters that precede \p Param in the template parameter list.
4927 /// \param QualifierLoc Will be set to the nested-name-specifier (with
4928 /// source-location information) that precedes the template name.
4930 /// \returns the substituted template argument, or NULL if an error occurred.
4932 SubstDefaultTemplateArgument(Sema &SemaRef,
4933 TemplateDecl *Template,
4934 SourceLocation TemplateLoc,
4935 SourceLocation RAngleLoc,
4936 TemplateTemplateParmDecl *Param,
4937 SmallVectorImpl<TemplateArgument> &Converted,
4938 NestedNameSpecifierLoc &QualifierLoc) {
4939 Sema::InstantiatingTemplate Inst(
4940 SemaRef, TemplateLoc, TemplateParameter(Param), Template, Converted,
4941 SourceRange(TemplateLoc, RAngleLoc));
4942 if (Inst.isInvalid())
4943 return TemplateName();
4945 TemplateArgumentList TemplateArgs(TemplateArgumentList::OnStack, Converted);
4947 // Only substitute for the innermost template argument list.
4948 MultiLevelTemplateArgumentList TemplateArgLists;
4949 TemplateArgLists.addOuterTemplateArguments(&TemplateArgs);
4950 for (unsigned i = 0, e = Param->getDepth(); i != e; ++i)
4951 TemplateArgLists.addOuterTemplateArguments(None);
4953 Sema::ContextRAII SavedContext(SemaRef, Template->getDeclContext());
4954 // Substitute into the nested-name-specifier first,
4955 QualifierLoc = Param->getDefaultArgument().getTemplateQualifierLoc();
4958 SemaRef.SubstNestedNameSpecifierLoc(QualifierLoc, TemplateArgLists);
4960 return TemplateName();
4963 return SemaRef.SubstTemplateName(
4965 Param->getDefaultArgument().getArgument().getAsTemplate(),
4966 Param->getDefaultArgument().getTemplateNameLoc(),
4970 /// If the given template parameter has a default template
4971 /// argument, substitute into that default template argument and
4972 /// return the corresponding template argument.
4974 Sema::SubstDefaultTemplateArgumentIfAvailable(TemplateDecl *Template,
4975 SourceLocation TemplateLoc,
4976 SourceLocation RAngleLoc,
4978 SmallVectorImpl<TemplateArgument>
4980 bool &HasDefaultArg) {
4981 HasDefaultArg = false;
4983 if (TemplateTypeParmDecl *TypeParm = dyn_cast<TemplateTypeParmDecl>(Param)) {
4984 if (!hasVisibleDefaultArgument(TypeParm))
4985 return TemplateArgumentLoc();
4987 HasDefaultArg = true;
4988 TypeSourceInfo *DI = SubstDefaultTemplateArgument(*this, Template,
4994 return TemplateArgumentLoc(TemplateArgument(DI->getType()), DI);
4996 return TemplateArgumentLoc();
4999 if (NonTypeTemplateParmDecl *NonTypeParm
5000 = dyn_cast<NonTypeTemplateParmDecl>(Param)) {
5001 if (!hasVisibleDefaultArgument(NonTypeParm))
5002 return TemplateArgumentLoc();
5004 HasDefaultArg = true;
5005 ExprResult Arg = SubstDefaultTemplateArgument(*this, Template,
5010 if (Arg.isInvalid())
5011 return TemplateArgumentLoc();
5013 Expr *ArgE = Arg.getAs<Expr>();
5014 return TemplateArgumentLoc(TemplateArgument(ArgE), ArgE);
5017 TemplateTemplateParmDecl *TempTempParm
5018 = cast<TemplateTemplateParmDecl>(Param);
5019 if (!hasVisibleDefaultArgument(TempTempParm))
5020 return TemplateArgumentLoc();
5022 HasDefaultArg = true;
5023 NestedNameSpecifierLoc QualifierLoc;
5024 TemplateName TName = SubstDefaultTemplateArgument(*this, Template,
5031 return TemplateArgumentLoc();
5033 return TemplateArgumentLoc(TemplateArgument(TName),
5034 TempTempParm->getDefaultArgument().getTemplateQualifierLoc(),
5035 TempTempParm->getDefaultArgument().getTemplateNameLoc());
5038 /// Convert a template-argument that we parsed as a type into a template, if
5039 /// possible. C++ permits injected-class-names to perform dual service as
5040 /// template template arguments and as template type arguments.
5041 static TemplateArgumentLoc convertTypeTemplateArgumentToTemplate(TypeLoc TLoc) {
5042 // Extract and step over any surrounding nested-name-specifier.
5043 NestedNameSpecifierLoc QualLoc;
5044 if (auto ETLoc = TLoc.getAs<ElaboratedTypeLoc>()) {
5045 if (ETLoc.getTypePtr()->getKeyword() != ETK_None)
5046 return TemplateArgumentLoc();
5048 QualLoc = ETLoc.getQualifierLoc();
5049 TLoc = ETLoc.getNamedTypeLoc();
5052 // If this type was written as an injected-class-name, it can be used as a
5053 // template template argument.
5054 if (auto InjLoc = TLoc.getAs<InjectedClassNameTypeLoc>())
5055 return TemplateArgumentLoc(InjLoc.getTypePtr()->getTemplateName(),
5056 QualLoc, InjLoc.getNameLoc());
5058 // If this type was written as an injected-class-name, it may have been
5059 // converted to a RecordType during instantiation. If the RecordType is
5060 // *not* wrapped in a TemplateSpecializationType and denotes a class
5061 // template specialization, it must have come from an injected-class-name.
5062 if (auto RecLoc = TLoc.getAs<RecordTypeLoc>())
5064 dyn_cast<ClassTemplateSpecializationDecl>(RecLoc.getDecl()))
5065 return TemplateArgumentLoc(TemplateName(CTSD->getSpecializedTemplate()),
5066 QualLoc, RecLoc.getNameLoc());
5068 return TemplateArgumentLoc();
5071 /// Check that the given template argument corresponds to the given
5072 /// template parameter.
5074 /// \param Param The template parameter against which the argument will be
5077 /// \param Arg The template argument, which may be updated due to conversions.
5079 /// \param Template The template in which the template argument resides.
5081 /// \param TemplateLoc The location of the template name for the template
5082 /// whose argument list we're matching.
5084 /// \param RAngleLoc The location of the right angle bracket ('>') that closes
5085 /// the template argument list.
5087 /// \param ArgumentPackIndex The index into the argument pack where this
5088 /// argument will be placed. Only valid if the parameter is a parameter pack.
5090 /// \param Converted The checked, converted argument will be added to the
5091 /// end of this small vector.
5093 /// \param CTAK Describes how we arrived at this particular template argument:
5094 /// explicitly written, deduced, etc.
5096 /// \returns true on error, false otherwise.
5097 bool Sema::CheckTemplateArgument(NamedDecl *Param,
5098 TemplateArgumentLoc &Arg,
5099 NamedDecl *Template,
5100 SourceLocation TemplateLoc,
5101 SourceLocation RAngleLoc,
5102 unsigned ArgumentPackIndex,
5103 SmallVectorImpl<TemplateArgument> &Converted,
5104 CheckTemplateArgumentKind CTAK) {
5105 // Check template type parameters.
5106 if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(Param))
5107 return CheckTemplateTypeArgument(TTP, Arg, Converted);
5109 // Check non-type template parameters.
5110 if (NonTypeTemplateParmDecl *NTTP =dyn_cast<NonTypeTemplateParmDecl>(Param)) {
5111 // Do substitution on the type of the non-type template parameter
5112 // with the template arguments we've seen thus far. But if the
5113 // template has a dependent context then we cannot substitute yet.
5114 QualType NTTPType = NTTP->getType();
5115 if (NTTP->isParameterPack() && NTTP->isExpandedParameterPack())
5116 NTTPType = NTTP->getExpansionType(ArgumentPackIndex);
5118 if (NTTPType->isInstantiationDependentType() &&
5119 !isa<TemplateTemplateParmDecl>(Template) &&
5120 !Template->getDeclContext()->isDependentContext()) {
5121 // Do substitution on the type of the non-type template parameter.
5122 InstantiatingTemplate Inst(*this, TemplateLoc, Template,
5124 SourceRange(TemplateLoc, RAngleLoc));
5125 if (Inst.isInvalid())
5128 TemplateArgumentList TemplateArgs(TemplateArgumentList::OnStack,
5131 // If the parameter is a pack expansion, expand this slice of the pack.
5132 if (auto *PET = NTTPType->getAs<PackExpansionType>()) {
5133 Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(*this,
5135 NTTPType = SubstType(PET->getPattern(),
5136 MultiLevelTemplateArgumentList(TemplateArgs),
5137 NTTP->getLocation(),
5138 NTTP->getDeclName());
5140 NTTPType = SubstType(NTTPType,
5141 MultiLevelTemplateArgumentList(TemplateArgs),
5142 NTTP->getLocation(),
5143 NTTP->getDeclName());
5146 // If that worked, check the non-type template parameter type
5148 if (!NTTPType.isNull())
5149 NTTPType = CheckNonTypeTemplateParameterType(NTTPType,
5150 NTTP->getLocation());
5151 if (NTTPType.isNull())
5155 switch (Arg.getArgument().getKind()) {
5156 case TemplateArgument::Null:
5157 llvm_unreachable("Should never see a NULL template argument here");
5159 case TemplateArgument::Expression: {
5160 TemplateArgument Result;
5161 unsigned CurSFINAEErrors = NumSFINAEErrors;
5163 CheckTemplateArgument(NTTP, NTTPType, Arg.getArgument().getAsExpr(),
5165 if (Res.isInvalid())
5167 // If the current template argument causes an error, give up now.
5168 if (CurSFINAEErrors < NumSFINAEErrors)
5171 // If the resulting expression is new, then use it in place of the
5172 // old expression in the template argument.
5173 if (Res.get() != Arg.getArgument().getAsExpr()) {
5174 TemplateArgument TA(Res.get());
5175 Arg = TemplateArgumentLoc(TA, Res.get());
5178 Converted.push_back(Result);
5182 case TemplateArgument::Declaration:
5183 case TemplateArgument::Integral:
5184 case TemplateArgument::NullPtr:
5185 // We've already checked this template argument, so just copy
5186 // it to the list of converted arguments.
5187 Converted.push_back(Arg.getArgument());
5190 case TemplateArgument::Template:
5191 case TemplateArgument::TemplateExpansion:
5192 // We were given a template template argument. It may not be ill-formed;
5194 if (DependentTemplateName *DTN
5195 = Arg.getArgument().getAsTemplateOrTemplatePattern()
5196 .getAsDependentTemplateName()) {
5197 // We have a template argument such as \c T::template X, which we
5198 // parsed as a template template argument. However, since we now
5199 // know that we need a non-type template argument, convert this
5200 // template name into an expression.
5202 DeclarationNameInfo NameInfo(DTN->getIdentifier(),
5203 Arg.getTemplateNameLoc());
5206 SS.Adopt(Arg.getTemplateQualifierLoc());
5207 // FIXME: the template-template arg was a DependentTemplateName,
5208 // so it was provided with a template keyword. However, its source
5209 // location is not stored in the template argument structure.
5210 SourceLocation TemplateKWLoc;
5211 ExprResult E = DependentScopeDeclRefExpr::Create(
5212 Context, SS.getWithLocInContext(Context), TemplateKWLoc, NameInfo,
5215 // If we parsed the template argument as a pack expansion, create a
5216 // pack expansion expression.
5217 if (Arg.getArgument().getKind() == TemplateArgument::TemplateExpansion){
5218 E = ActOnPackExpansion(E.get(), Arg.getTemplateEllipsisLoc());
5223 TemplateArgument Result;
5224 E = CheckTemplateArgument(NTTP, NTTPType, E.get(), Result);
5228 Converted.push_back(Result);
5232 // We have a template argument that actually does refer to a class
5233 // template, alias template, or template template parameter, and
5234 // therefore cannot be a non-type template argument.
5235 Diag(Arg.getLocation(), diag::err_template_arg_must_be_expr)
5236 << Arg.getSourceRange();
5238 Diag(Param->getLocation(), diag::note_template_param_here);
5241 case TemplateArgument::Type: {
5242 // We have a non-type template parameter but the template
5243 // argument is a type.
5245 // C++ [temp.arg]p2:
5246 // In a template-argument, an ambiguity between a type-id and
5247 // an expression is resolved to a type-id, regardless of the
5248 // form of the corresponding template-parameter.
5250 // We warn specifically about this case, since it can be rather
5251 // confusing for users.
5252 QualType T = Arg.getArgument().getAsType();
5253 SourceRange SR = Arg.getSourceRange();
5254 if (T->isFunctionType())
5255 Diag(SR.getBegin(), diag::err_template_arg_nontype_ambig) << SR << T;
5257 Diag(SR.getBegin(), diag::err_template_arg_must_be_expr) << SR;
5258 Diag(Param->getLocation(), diag::note_template_param_here);
5262 case TemplateArgument::Pack:
5263 llvm_unreachable("Caller must expand template argument packs");
5270 // Check template template parameters.
5271 TemplateTemplateParmDecl *TempParm = cast<TemplateTemplateParmDecl>(Param);
5273 TemplateParameterList *Params = TempParm->getTemplateParameters();
5274 if (TempParm->isExpandedParameterPack())
5275 Params = TempParm->getExpansionTemplateParameters(ArgumentPackIndex);
5277 // Substitute into the template parameter list of the template
5278 // template parameter, since previously-supplied template arguments
5279 // may appear within the template template parameter.
5281 // FIXME: Skip this if the parameters aren't instantiation-dependent.
5283 // Set up a template instantiation context.
5284 LocalInstantiationScope Scope(*this);
5285 InstantiatingTemplate Inst(*this, TemplateLoc, Template,
5286 TempParm, Converted,
5287 SourceRange(TemplateLoc, RAngleLoc));
5288 if (Inst.isInvalid())
5291 TemplateArgumentList TemplateArgs(TemplateArgumentList::OnStack, Converted);
5292 Params = SubstTemplateParams(Params, CurContext,
5293 MultiLevelTemplateArgumentList(TemplateArgs));
5298 // C++1z [temp.local]p1: (DR1004)
5299 // When [the injected-class-name] is used [...] as a template-argument for
5300 // a template template-parameter [...] it refers to the class template
5302 if (Arg.getArgument().getKind() == TemplateArgument::Type) {
5303 TemplateArgumentLoc ConvertedArg = convertTypeTemplateArgumentToTemplate(
5304 Arg.getTypeSourceInfo()->getTypeLoc());
5305 if (!ConvertedArg.getArgument().isNull())
5309 switch (Arg.getArgument().getKind()) {
5310 case TemplateArgument::Null:
5311 llvm_unreachable("Should never see a NULL template argument here");
5313 case TemplateArgument::Template:
5314 case TemplateArgument::TemplateExpansion:
5315 if (CheckTemplateTemplateArgument(TempParm, Params, Arg))
5318 Converted.push_back(Arg.getArgument());
5321 case TemplateArgument::Expression:
5322 case TemplateArgument::Type:
5323 // We have a template template parameter but the template
5324 // argument does not refer to a template.
5325 Diag(Arg.getLocation(), diag::err_template_arg_must_be_template)
5326 << getLangOpts().CPlusPlus11;
5329 case TemplateArgument::Declaration:
5330 llvm_unreachable("Declaration argument with template template parameter");
5331 case TemplateArgument::Integral:
5332 llvm_unreachable("Integral argument with template template parameter");
5333 case TemplateArgument::NullPtr:
5334 llvm_unreachable("Null pointer argument with template template parameter");
5336 case TemplateArgument::Pack:
5337 llvm_unreachable("Caller must expand template argument packs");
5343 /// Check whether the template parameter is a pack expansion, and if so,
5344 /// determine the number of parameters produced by that expansion. For instance:
5347 /// template<typename ...Ts> struct A {
5348 /// template<Ts ...NTs, template<Ts> class ...TTs, typename ...Us> struct B;
5352 /// In \c A<int,int>::B, \c NTs and \c TTs have expanded pack size 2, and \c Us
5353 /// is not a pack expansion, so returns an empty Optional.
5354 static Optional<unsigned> getExpandedPackSize(NamedDecl *Param) {
5355 if (TemplateTypeParmDecl *TTP
5356 = dyn_cast<TemplateTypeParmDecl>(Param)) {
5357 if (TTP->isExpandedParameterPack())
5358 return TTP->getNumExpansionParameters();
5361 if (NonTypeTemplateParmDecl *NTTP
5362 = dyn_cast<NonTypeTemplateParmDecl>(Param)) {
5363 if (NTTP->isExpandedParameterPack())
5364 return NTTP->getNumExpansionTypes();
5367 if (TemplateTemplateParmDecl *TTP
5368 = dyn_cast<TemplateTemplateParmDecl>(Param)) {
5369 if (TTP->isExpandedParameterPack())
5370 return TTP->getNumExpansionTemplateParameters();
5376 /// Diagnose a missing template argument.
5377 template<typename TemplateParmDecl>
5378 static bool diagnoseMissingArgument(Sema &S, SourceLocation Loc,
5380 const TemplateParmDecl *D,
5381 TemplateArgumentListInfo &Args) {
5382 // Dig out the most recent declaration of the template parameter; there may be
5383 // declarations of the template that are more recent than TD.
5384 D = cast<TemplateParmDecl>(cast<TemplateDecl>(TD->getMostRecentDecl())
5385 ->getTemplateParameters()
5386 ->getParam(D->getIndex()));
5388 // If there's a default argument that's not visible, diagnose that we're
5389 // missing a module import.
5390 llvm::SmallVector<Module*, 8> Modules;
5391 if (D->hasDefaultArgument() && !S.hasVisibleDefaultArgument(D, &Modules)) {
5392 S.diagnoseMissingImport(Loc, cast<NamedDecl>(TD),
5393 D->getDefaultArgumentLoc(), Modules,
5394 Sema::MissingImportKind::DefaultArgument,
5399 // FIXME: If there's a more recent default argument that *is* visible,
5400 // diagnose that it was declared too late.
5402 TemplateParameterList *Params = TD->getTemplateParameters();
5404 S.Diag(Loc, diag::err_template_arg_list_different_arity)
5405 << /*not enough args*/0
5406 << (int)S.getTemplateNameKindForDiagnostics(TemplateName(TD))
5408 S.Diag(TD->getLocation(), diag::note_template_decl_here)
5409 << Params->getSourceRange();
5413 /// Check that the given template argument list is well-formed
5414 /// for specializing the given template.
5415 bool Sema::CheckTemplateArgumentList(
5416 TemplateDecl *Template, SourceLocation TemplateLoc,
5417 TemplateArgumentListInfo &TemplateArgs, bool PartialTemplateArgs,
5418 SmallVectorImpl<TemplateArgument> &Converted,
5419 bool UpdateArgsWithConversions, bool *ConstraintsNotSatisfied) {
5421 if (ConstraintsNotSatisfied)
5422 *ConstraintsNotSatisfied = false;
5424 // Make a copy of the template arguments for processing. Only make the
5425 // changes at the end when successful in matching the arguments to the
5427 TemplateArgumentListInfo NewArgs = TemplateArgs;
5429 // Make sure we get the template parameter list from the most
5430 // recentdeclaration, since that is the only one that has is guaranteed to
5431 // have all the default template argument information.
5432 TemplateParameterList *Params =
5433 cast<TemplateDecl>(Template->getMostRecentDecl())
5434 ->getTemplateParameters();
5436 SourceLocation RAngleLoc = NewArgs.getRAngleLoc();
5438 // C++ [temp.arg]p1:
5439 // [...] The type and form of each template-argument specified in
5440 // a template-id shall match the type and form specified for the
5441 // corresponding parameter declared by the template in its
5442 // template-parameter-list.
5443 bool isTemplateTemplateParameter = isa<TemplateTemplateParmDecl>(Template);
5444 SmallVector<TemplateArgument, 2> ArgumentPack;
5445 unsigned ArgIdx = 0, NumArgs = NewArgs.size();
5446 LocalInstantiationScope InstScope(*this, true);
5447 for (TemplateParameterList::iterator Param = Params->begin(),
5448 ParamEnd = Params->end();
5449 Param != ParamEnd; /* increment in loop */) {
5450 // If we have an expanded parameter pack, make sure we don't have too
5452 if (Optional<unsigned> Expansions = getExpandedPackSize(*Param)) {
5453 if (*Expansions == ArgumentPack.size()) {
5454 // We're done with this parameter pack. Pack up its arguments and add
5455 // them to the list.
5456 Converted.push_back(
5457 TemplateArgument::CreatePackCopy(Context, ArgumentPack));
5458 ArgumentPack.clear();
5460 // This argument is assigned to the next parameter.
5463 } else if (ArgIdx == NumArgs && !PartialTemplateArgs) {
5464 // Not enough arguments for this parameter pack.
5465 Diag(TemplateLoc, diag::err_template_arg_list_different_arity)
5466 << /*not enough args*/0
5467 << (int)getTemplateNameKindForDiagnostics(TemplateName(Template))
5469 Diag(Template->getLocation(), diag::note_template_decl_here)
5470 << Params->getSourceRange();
5475 if (ArgIdx < NumArgs) {
5476 // Check the template argument we were given.
5477 if (CheckTemplateArgument(*Param, NewArgs[ArgIdx], Template,
5478 TemplateLoc, RAngleLoc,
5479 ArgumentPack.size(), Converted))
5482 bool PackExpansionIntoNonPack =
5483 NewArgs[ArgIdx].getArgument().isPackExpansion() &&
5484 (!(*Param)->isTemplateParameterPack() || getExpandedPackSize(*Param));
5485 if (PackExpansionIntoNonPack && (isa<TypeAliasTemplateDecl>(Template) ||
5486 isa<ConceptDecl>(Template))) {
5487 // Core issue 1430: we have a pack expansion as an argument to an
5488 // alias template, and it's not part of a parameter pack. This
5489 // can't be canonicalized, so reject it now.
5490 // As for concepts - we cannot normalize constraints where this
5491 // situation exists.
5492 Diag(NewArgs[ArgIdx].getLocation(),
5493 diag::err_template_expansion_into_fixed_list)
5494 << (isa<ConceptDecl>(Template) ? 1 : 0)
5495 << NewArgs[ArgIdx].getSourceRange();
5496 Diag((*Param)->getLocation(), diag::note_template_param_here);
5500 // We're now done with this argument.
5503 if ((*Param)->isTemplateParameterPack()) {
5504 // The template parameter was a template parameter pack, so take the
5505 // deduced argument and place it on the argument pack. Note that we
5506 // stay on the same template parameter so that we can deduce more
5508 ArgumentPack.push_back(Converted.pop_back_val());
5510 // Move to the next template parameter.
5514 // If we just saw a pack expansion into a non-pack, then directly convert
5515 // the remaining arguments, because we don't know what parameters they'll
5517 if (PackExpansionIntoNonPack) {
5518 if (!ArgumentPack.empty()) {
5519 // If we were part way through filling in an expanded parameter pack,
5520 // fall back to just producing individual arguments.
5521 Converted.insert(Converted.end(),
5522 ArgumentPack.begin(), ArgumentPack.end());
5523 ArgumentPack.clear();
5526 while (ArgIdx < NumArgs) {
5527 Converted.push_back(NewArgs[ArgIdx].getArgument());
5537 // If we're checking a partial template argument list, we're done.
5538 if (PartialTemplateArgs) {
5539 if ((*Param)->isTemplateParameterPack() && !ArgumentPack.empty())
5540 Converted.push_back(
5541 TemplateArgument::CreatePackCopy(Context, ArgumentPack));
5545 // If we have a template parameter pack with no more corresponding
5546 // arguments, just break out now and we'll fill in the argument pack below.
5547 if ((*Param)->isTemplateParameterPack()) {
5548 assert(!getExpandedPackSize(*Param) &&
5549 "Should have dealt with this already");
5551 // A non-expanded parameter pack before the end of the parameter list
5552 // only occurs for an ill-formed template parameter list, unless we've
5553 // got a partial argument list for a function template, so just bail out.
5554 if (Param + 1 != ParamEnd)
5557 Converted.push_back(
5558 TemplateArgument::CreatePackCopy(Context, ArgumentPack));
5559 ArgumentPack.clear();
5565 // Check whether we have a default argument.
5566 TemplateArgumentLoc Arg;
5568 // Retrieve the default template argument from the template
5569 // parameter. For each kind of template parameter, we substitute the
5570 // template arguments provided thus far and any "outer" template arguments
5571 // (when the template parameter was part of a nested template) into
5572 // the default argument.
5573 if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(*Param)) {
5574 if (!hasVisibleDefaultArgument(TTP))
5575 return diagnoseMissingArgument(*this, TemplateLoc, Template, TTP,
5578 TypeSourceInfo *ArgType = SubstDefaultTemplateArgument(*this,
5587 Arg = TemplateArgumentLoc(TemplateArgument(ArgType->getType()),
5589 } else if (NonTypeTemplateParmDecl *NTTP
5590 = dyn_cast<NonTypeTemplateParmDecl>(*Param)) {
5591 if (!hasVisibleDefaultArgument(NTTP))
5592 return diagnoseMissingArgument(*this, TemplateLoc, Template, NTTP,
5595 ExprResult E = SubstDefaultTemplateArgument(*this, Template,
5603 Expr *Ex = E.getAs<Expr>();
5604 Arg = TemplateArgumentLoc(TemplateArgument(Ex), Ex);
5606 TemplateTemplateParmDecl *TempParm
5607 = cast<TemplateTemplateParmDecl>(*Param);
5609 if (!hasVisibleDefaultArgument(TempParm))
5610 return diagnoseMissingArgument(*this, TemplateLoc, Template, TempParm,
5613 NestedNameSpecifierLoc QualifierLoc;
5614 TemplateName Name = SubstDefaultTemplateArgument(*this, Template,
5623 Arg = TemplateArgumentLoc(TemplateArgument(Name), QualifierLoc,
5624 TempParm->getDefaultArgument().getTemplateNameLoc());
5627 // Introduce an instantiation record that describes where we are using
5628 // the default template argument. We're not actually instantiating a
5629 // template here, we just create this object to put a note into the
5631 InstantiatingTemplate Inst(*this, RAngleLoc, Template, *Param, Converted,
5632 SourceRange(TemplateLoc, RAngleLoc));
5633 if (Inst.isInvalid())
5636 // Check the default template argument.
5637 if (CheckTemplateArgument(*Param, Arg, Template, TemplateLoc,
5638 RAngleLoc, 0, Converted))
5641 // Core issue 150 (assumed resolution): if this is a template template
5642 // parameter, keep track of the default template arguments from the
5643 // template definition.
5644 if (isTemplateTemplateParameter)
5645 NewArgs.addArgument(Arg);
5647 // Move to the next template parameter and argument.
5652 // If we're performing a partial argument substitution, allow any trailing
5653 // pack expansions; they might be empty. This can happen even if
5654 // PartialTemplateArgs is false (the list of arguments is complete but
5655 // still dependent).
5656 if (ArgIdx < NumArgs && CurrentInstantiationScope &&
5657 CurrentInstantiationScope->getPartiallySubstitutedPack()) {
5658 while (ArgIdx < NumArgs && NewArgs[ArgIdx].getArgument().isPackExpansion())
5659 Converted.push_back(NewArgs[ArgIdx++].getArgument());
5662 // If we have any leftover arguments, then there were too many arguments.
5663 // Complain and fail.
5664 if (ArgIdx < NumArgs) {
5665 Diag(TemplateLoc, diag::err_template_arg_list_different_arity)
5666 << /*too many args*/1
5667 << (int)getTemplateNameKindForDiagnostics(TemplateName(Template))
5669 << SourceRange(NewArgs[ArgIdx].getLocation(), NewArgs.getRAngleLoc());
5670 Diag(Template->getLocation(), diag::note_template_decl_here)
5671 << Params->getSourceRange();
5675 // No problems found with the new argument list, propagate changes back
5677 if (UpdateArgsWithConversions)
5678 TemplateArgs = std::move(NewArgs);
5680 if (!PartialTemplateArgs &&
5681 EnsureTemplateArgumentListConstraints(
5682 Template, Converted, SourceRange(TemplateLoc,
5683 TemplateArgs.getRAngleLoc()))) {
5684 if (ConstraintsNotSatisfied)
5685 *ConstraintsNotSatisfied = true;
5693 class UnnamedLocalNoLinkageFinder
5694 : public TypeVisitor<UnnamedLocalNoLinkageFinder, bool>
5699 typedef TypeVisitor<UnnamedLocalNoLinkageFinder, bool> inherited;
5702 UnnamedLocalNoLinkageFinder(Sema &S, SourceRange SR) : S(S), SR(SR) { }
5704 bool Visit(QualType T) {
5705 return T.isNull() ? false : inherited::Visit(T.getTypePtr());
5708 #define TYPE(Class, Parent) \
5709 bool Visit##Class##Type(const Class##Type *);
5710 #define ABSTRACT_TYPE(Class, Parent) \
5711 bool Visit##Class##Type(const Class##Type *) { return false; }
5712 #define NON_CANONICAL_TYPE(Class, Parent) \
5713 bool Visit##Class##Type(const Class##Type *) { return false; }
5714 #include "clang/AST/TypeNodes.inc"
5716 bool VisitTagDecl(const TagDecl *Tag);
5717 bool VisitNestedNameSpecifier(NestedNameSpecifier *NNS);
5719 } // end anonymous namespace
5721 bool UnnamedLocalNoLinkageFinder::VisitBuiltinType(const BuiltinType*) {
5725 bool UnnamedLocalNoLinkageFinder::VisitComplexType(const ComplexType* T) {
5726 return Visit(T->getElementType());
5729 bool UnnamedLocalNoLinkageFinder::VisitPointerType(const PointerType* T) {
5730 return Visit(T->getPointeeType());
5733 bool UnnamedLocalNoLinkageFinder::VisitBlockPointerType(
5734 const BlockPointerType* T) {
5735 return Visit(T->getPointeeType());
5738 bool UnnamedLocalNoLinkageFinder::VisitLValueReferenceType(
5739 const LValueReferenceType* T) {
5740 return Visit(T->getPointeeType());
5743 bool UnnamedLocalNoLinkageFinder::VisitRValueReferenceType(
5744 const RValueReferenceType* T) {
5745 return Visit(T->getPointeeType());
5748 bool UnnamedLocalNoLinkageFinder::VisitMemberPointerType(
5749 const MemberPointerType* T) {
5750 return Visit(T->getPointeeType()) || Visit(QualType(T->getClass(), 0));
5753 bool UnnamedLocalNoLinkageFinder::VisitConstantArrayType(
5754 const ConstantArrayType* T) {
5755 return Visit(T->getElementType());
5758 bool UnnamedLocalNoLinkageFinder::VisitIncompleteArrayType(
5759 const IncompleteArrayType* T) {
5760 return Visit(T->getElementType());
5763 bool UnnamedLocalNoLinkageFinder::VisitVariableArrayType(
5764 const VariableArrayType* T) {
5765 return Visit(T->getElementType());
5768 bool UnnamedLocalNoLinkageFinder::VisitDependentSizedArrayType(
5769 const DependentSizedArrayType* T) {
5770 return Visit(T->getElementType());
5773 bool UnnamedLocalNoLinkageFinder::VisitDependentSizedExtVectorType(
5774 const DependentSizedExtVectorType* T) {
5775 return Visit(T->getElementType());
5778 bool UnnamedLocalNoLinkageFinder::VisitDependentAddressSpaceType(
5779 const DependentAddressSpaceType *T) {
5780 return Visit(T->getPointeeType());
5783 bool UnnamedLocalNoLinkageFinder::VisitVectorType(const VectorType* T) {
5784 return Visit(T->getElementType());
5787 bool UnnamedLocalNoLinkageFinder::VisitDependentVectorType(
5788 const DependentVectorType *T) {
5789 return Visit(T->getElementType());
5792 bool UnnamedLocalNoLinkageFinder::VisitExtVectorType(const ExtVectorType* T) {
5793 return Visit(T->getElementType());
5796 bool UnnamedLocalNoLinkageFinder::VisitFunctionProtoType(
5797 const FunctionProtoType* T) {
5798 for (const auto &A : T->param_types()) {
5803 return Visit(T->getReturnType());
5806 bool UnnamedLocalNoLinkageFinder::VisitFunctionNoProtoType(
5807 const FunctionNoProtoType* T) {
5808 return Visit(T->getReturnType());
5811 bool UnnamedLocalNoLinkageFinder::VisitUnresolvedUsingType(
5812 const UnresolvedUsingType*) {
5816 bool UnnamedLocalNoLinkageFinder::VisitTypeOfExprType(const TypeOfExprType*) {
5820 bool UnnamedLocalNoLinkageFinder::VisitTypeOfType(const TypeOfType* T) {
5821 return Visit(T->getUnderlyingType());
5824 bool UnnamedLocalNoLinkageFinder::VisitDecltypeType(const DecltypeType*) {
5828 bool UnnamedLocalNoLinkageFinder::VisitUnaryTransformType(
5829 const UnaryTransformType*) {
5833 bool UnnamedLocalNoLinkageFinder::VisitAutoType(const AutoType *T) {
5834 return Visit(T->getDeducedType());
5837 bool UnnamedLocalNoLinkageFinder::VisitDeducedTemplateSpecializationType(
5838 const DeducedTemplateSpecializationType *T) {
5839 return Visit(T->getDeducedType());
5842 bool UnnamedLocalNoLinkageFinder::VisitRecordType(const RecordType* T) {
5843 return VisitTagDecl(T->getDecl());
5846 bool UnnamedLocalNoLinkageFinder::VisitEnumType(const EnumType* T) {
5847 return VisitTagDecl(T->getDecl());
5850 bool UnnamedLocalNoLinkageFinder::VisitTemplateTypeParmType(
5851 const TemplateTypeParmType*) {
5855 bool UnnamedLocalNoLinkageFinder::VisitSubstTemplateTypeParmPackType(
5856 const SubstTemplateTypeParmPackType *) {
5860 bool UnnamedLocalNoLinkageFinder::VisitTemplateSpecializationType(
5861 const TemplateSpecializationType*) {
5865 bool UnnamedLocalNoLinkageFinder::VisitInjectedClassNameType(
5866 const InjectedClassNameType* T) {
5867 return VisitTagDecl(T->getDecl());
5870 bool UnnamedLocalNoLinkageFinder::VisitDependentNameType(
5871 const DependentNameType* T) {
5872 return VisitNestedNameSpecifier(T->getQualifier());
5875 bool UnnamedLocalNoLinkageFinder::VisitDependentTemplateSpecializationType(
5876 const DependentTemplateSpecializationType* T) {
5877 return VisitNestedNameSpecifier(T->getQualifier());
5880 bool UnnamedLocalNoLinkageFinder::VisitPackExpansionType(
5881 const PackExpansionType* T) {
5882 return Visit(T->getPattern());
5885 bool UnnamedLocalNoLinkageFinder::VisitObjCObjectType(const ObjCObjectType *) {
5889 bool UnnamedLocalNoLinkageFinder::VisitObjCInterfaceType(
5890 const ObjCInterfaceType *) {
5894 bool UnnamedLocalNoLinkageFinder::VisitObjCObjectPointerType(
5895 const ObjCObjectPointerType *) {
5899 bool UnnamedLocalNoLinkageFinder::VisitAtomicType(const AtomicType* T) {
5900 return Visit(T->getValueType());
5903 bool UnnamedLocalNoLinkageFinder::VisitPipeType(const PipeType* T) {
5907 bool UnnamedLocalNoLinkageFinder::VisitTagDecl(const TagDecl *Tag) {
5908 if (Tag->getDeclContext()->isFunctionOrMethod()) {
5909 S.Diag(SR.getBegin(),
5910 S.getLangOpts().CPlusPlus11 ?
5911 diag::warn_cxx98_compat_template_arg_local_type :
5912 diag::ext_template_arg_local_type)
5913 << S.Context.getTypeDeclType(Tag) << SR;
5917 if (!Tag->hasNameForLinkage()) {
5918 S.Diag(SR.getBegin(),
5919 S.getLangOpts().CPlusPlus11 ?
5920 diag::warn_cxx98_compat_template_arg_unnamed_type :
5921 diag::ext_template_arg_unnamed_type) << SR;
5922 S.Diag(Tag->getLocation(), diag::note_template_unnamed_type_here);
5929 bool UnnamedLocalNoLinkageFinder::VisitNestedNameSpecifier(
5930 NestedNameSpecifier *NNS) {
5931 if (NNS->getPrefix() && VisitNestedNameSpecifier(NNS->getPrefix()))
5934 switch (NNS->getKind()) {
5935 case NestedNameSpecifier::Identifier:
5936 case NestedNameSpecifier::Namespace:
5937 case NestedNameSpecifier::NamespaceAlias:
5938 case NestedNameSpecifier::Global:
5939 case NestedNameSpecifier::Super:
5942 case NestedNameSpecifier::TypeSpec:
5943 case NestedNameSpecifier::TypeSpecWithTemplate:
5944 return Visit(QualType(NNS->getAsType(), 0));
5946 llvm_unreachable("Invalid NestedNameSpecifier::Kind!");
5949 /// Check a template argument against its corresponding
5950 /// template type parameter.
5952 /// This routine implements the semantics of C++ [temp.arg.type]. It
5953 /// returns true if an error occurred, and false otherwise.
5954 bool Sema::CheckTemplateArgument(TemplateTypeParmDecl *Param,
5955 TypeSourceInfo *ArgInfo) {
5956 assert(ArgInfo && "invalid TypeSourceInfo");
5957 QualType Arg = ArgInfo->getType();
5958 SourceRange SR = ArgInfo->getTypeLoc().getSourceRange();
5960 if (Arg->isVariablyModifiedType()) {
5961 return Diag(SR.getBegin(), diag::err_variably_modified_template_arg) << Arg;
5962 } else if (Context.hasSameUnqualifiedType(Arg, Context.OverloadTy)) {
5963 return Diag(SR.getBegin(), diag::err_template_arg_overload_type) << SR;
5966 // C++03 [temp.arg.type]p2:
5967 // A local type, a type with no linkage, an unnamed type or a type
5968 // compounded from any of these types shall not be used as a
5969 // template-argument for a template type-parameter.
5971 // C++11 allows these, and even in C++03 we allow them as an extension with
5973 if (LangOpts.CPlusPlus11 || Arg->hasUnnamedOrLocalType()) {
5974 UnnamedLocalNoLinkageFinder Finder(*this, SR);
5975 (void)Finder.Visit(Context.getCanonicalType(Arg));
5981 enum NullPointerValueKind {
5987 /// Determine whether the given template argument is a null pointer
5988 /// value of the appropriate type.
5989 static NullPointerValueKind
5990 isNullPointerValueTemplateArgument(Sema &S, NonTypeTemplateParmDecl *Param,
5991 QualType ParamType, Expr *Arg,
5992 Decl *Entity = nullptr) {
5993 if (Arg->isValueDependent() || Arg->isTypeDependent())
5994 return NPV_NotNullPointer;
5996 // dllimport'd entities aren't constant but are available inside of template
5998 if (Entity && Entity->hasAttr<DLLImportAttr>())
5999 return NPV_NotNullPointer;
6001 if (!S.isCompleteType(Arg->getExprLoc(), ParamType))
6003 "Incomplete parameter type in isNullPointerValueTemplateArgument!");
6005 if (!S.getLangOpts().CPlusPlus11)
6006 return NPV_NotNullPointer;
6008 // Determine whether we have a constant expression.
6009 ExprResult ArgRV = S.DefaultFunctionArrayConversion(Arg);
6010 if (ArgRV.isInvalid())
6014 Expr::EvalResult EvalResult;
6015 SmallVector<PartialDiagnosticAt, 8> Notes;
6016 EvalResult.Diag = &Notes;
6017 if (!Arg->EvaluateAsRValue(EvalResult, S.Context) ||
6018 EvalResult.HasSideEffects) {
6019 SourceLocation DiagLoc = Arg->getExprLoc();
6021 // If our only note is the usual "invalid subexpression" note, just point
6022 // the caret at its location rather than producing an essentially
6024 if (Notes.size() == 1 && Notes[0].second.getDiagID() ==
6025 diag::note_invalid_subexpr_in_const_expr) {
6026 DiagLoc = Notes[0].first;
6030 S.Diag(DiagLoc, diag::err_template_arg_not_address_constant)
6031 << Arg->getType() << Arg->getSourceRange();
6032 for (unsigned I = 0, N = Notes.size(); I != N; ++I)
6033 S.Diag(Notes[I].first, Notes[I].second);
6035 S.Diag(Param->getLocation(), diag::note_template_param_here);
6039 // C++11 [temp.arg.nontype]p1:
6040 // - an address constant expression of type std::nullptr_t
6041 if (Arg->getType()->isNullPtrType())
6042 return NPV_NullPointer;
6044 // - a constant expression that evaluates to a null pointer value (4.10); or
6045 // - a constant expression that evaluates to a null member pointer value
6047 if ((EvalResult.Val.isLValue() && !EvalResult.Val.getLValueBase()) ||
6048 (EvalResult.Val.isMemberPointer() &&
6049 !EvalResult.Val.getMemberPointerDecl())) {
6050 // If our expression has an appropriate type, we've succeeded.
6051 bool ObjCLifetimeConversion;
6052 if (S.Context.hasSameUnqualifiedType(Arg->getType(), ParamType) ||
6053 S.IsQualificationConversion(Arg->getType(), ParamType, false,
6054 ObjCLifetimeConversion))
6055 return NPV_NullPointer;
6057 // The types didn't match, but we know we got a null pointer; complain,
6058 // then recover as if the types were correct.
6059 S.Diag(Arg->getExprLoc(), diag::err_template_arg_wrongtype_null_constant)
6060 << Arg->getType() << ParamType << Arg->getSourceRange();
6061 S.Diag(Param->getLocation(), diag::note_template_param_here);
6062 return NPV_NullPointer;
6065 // If we don't have a null pointer value, but we do have a NULL pointer
6066 // constant, suggest a cast to the appropriate type.
6067 if (Arg->isNullPointerConstant(S.Context, Expr::NPC_NeverValueDependent)) {
6068 std::string Code = "static_cast<" + ParamType.getAsString() + ">(";
6069 S.Diag(Arg->getExprLoc(), diag::err_template_arg_untyped_null_constant)
6070 << ParamType << FixItHint::CreateInsertion(Arg->getBeginLoc(), Code)
6071 << FixItHint::CreateInsertion(S.getLocForEndOfToken(Arg->getEndLoc()),
6073 S.Diag(Param->getLocation(), diag::note_template_param_here);
6074 return NPV_NullPointer;
6077 // FIXME: If we ever want to support general, address-constant expressions
6078 // as non-type template arguments, we should return the ExprResult here to
6079 // be interpreted by the caller.
6080 return NPV_NotNullPointer;
6083 /// Checks whether the given template argument is compatible with its
6084 /// template parameter.
6085 static bool CheckTemplateArgumentIsCompatibleWithParameter(
6086 Sema &S, NonTypeTemplateParmDecl *Param, QualType ParamType, Expr *ArgIn,
6087 Expr *Arg, QualType ArgType) {
6088 bool ObjCLifetimeConversion;
6089 if (ParamType->isPointerType() &&
6090 !ParamType->castAs<PointerType>()->getPointeeType()->isFunctionType() &&
6091 S.IsQualificationConversion(ArgType, ParamType, false,
6092 ObjCLifetimeConversion)) {
6093 // For pointer-to-object types, qualification conversions are
6096 if (const ReferenceType *ParamRef = ParamType->getAs<ReferenceType>()) {
6097 if (!ParamRef->getPointeeType()->isFunctionType()) {
6098 // C++ [temp.arg.nontype]p5b3:
6099 // For a non-type template-parameter of type reference to
6100 // object, no conversions apply. The type referred to by the
6101 // reference may be more cv-qualified than the (otherwise
6102 // identical) type of the template- argument. The
6103 // template-parameter is bound directly to the
6104 // template-argument, which shall be an lvalue.
6106 // FIXME: Other qualifiers?
6107 unsigned ParamQuals = ParamRef->getPointeeType().getCVRQualifiers();
6108 unsigned ArgQuals = ArgType.getCVRQualifiers();
6110 if ((ParamQuals | ArgQuals) != ParamQuals) {
6111 S.Diag(Arg->getBeginLoc(),
6112 diag::err_template_arg_ref_bind_ignores_quals)
6113 << ParamType << Arg->getType() << Arg->getSourceRange();
6114 S.Diag(Param->getLocation(), diag::note_template_param_here);
6120 // At this point, the template argument refers to an object or
6121 // function with external linkage. We now need to check whether the
6122 // argument and parameter types are compatible.
6123 if (!S.Context.hasSameUnqualifiedType(ArgType,
6124 ParamType.getNonReferenceType())) {
6125 // We can't perform this conversion or binding.
6126 if (ParamType->isReferenceType())
6127 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_no_ref_bind)
6128 << ParamType << ArgIn->getType() << Arg->getSourceRange();
6130 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_not_convertible)
6131 << ArgIn->getType() << ParamType << Arg->getSourceRange();
6132 S.Diag(Param->getLocation(), diag::note_template_param_here);
6140 /// Checks whether the given template argument is the address
6141 /// of an object or function according to C++ [temp.arg.nontype]p1.
6143 CheckTemplateArgumentAddressOfObjectOrFunction(Sema &S,
6144 NonTypeTemplateParmDecl *Param,
6147 TemplateArgument &Converted) {
6148 bool Invalid = false;
6150 QualType ArgType = Arg->getType();
6152 bool AddressTaken = false;
6153 SourceLocation AddrOpLoc;
6154 if (S.getLangOpts().MicrosoftExt) {
6155 // Microsoft Visual C++ strips all casts, allows an arbitrary number of
6156 // dereference and address-of operators.
6157 Arg = Arg->IgnoreParenCasts();
6159 bool ExtWarnMSTemplateArg = false;
6160 UnaryOperatorKind FirstOpKind;
6161 SourceLocation FirstOpLoc;
6162 while (UnaryOperator *UnOp = dyn_cast<UnaryOperator>(Arg)) {
6163 UnaryOperatorKind UnOpKind = UnOp->getOpcode();
6164 if (UnOpKind == UO_Deref)
6165 ExtWarnMSTemplateArg = true;
6166 if (UnOpKind == UO_AddrOf || UnOpKind == UO_Deref) {
6167 Arg = UnOp->getSubExpr()->IgnoreParenCasts();
6168 if (!AddrOpLoc.isValid()) {
6169 FirstOpKind = UnOpKind;
6170 FirstOpLoc = UnOp->getOperatorLoc();
6175 if (FirstOpLoc.isValid()) {
6176 if (ExtWarnMSTemplateArg)
6177 S.Diag(ArgIn->getBeginLoc(), diag::ext_ms_deref_template_argument)
6178 << ArgIn->getSourceRange();
6180 if (FirstOpKind == UO_AddrOf)
6181 AddressTaken = true;
6182 else if (Arg->getType()->isPointerType()) {
6183 // We cannot let pointers get dereferenced here, that is obviously not a
6184 // constant expression.
6185 assert(FirstOpKind == UO_Deref);
6186 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_not_decl_ref)
6187 << Arg->getSourceRange();
6191 // See through any implicit casts we added to fix the type.
6192 Arg = Arg->IgnoreImpCasts();
6194 // C++ [temp.arg.nontype]p1:
6196 // A template-argument for a non-type, non-template
6197 // template-parameter shall be one of: [...]
6199 // -- the address of an object or function with external
6200 // linkage, including function templates and function
6201 // template-ids but excluding non-static class members,
6202 // expressed as & id-expression where the & is optional if
6203 // the name refers to a function or array, or if the
6204 // corresponding template-parameter is a reference; or
6206 // In C++98/03 mode, give an extension warning on any extra parentheses.
6207 // See http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#773
6208 bool ExtraParens = false;
6209 while (ParenExpr *Parens = dyn_cast<ParenExpr>(Arg)) {
6210 if (!Invalid && !ExtraParens) {
6211 S.Diag(Arg->getBeginLoc(),
6212 S.getLangOpts().CPlusPlus11
6213 ? diag::warn_cxx98_compat_template_arg_extra_parens
6214 : diag::ext_template_arg_extra_parens)
6215 << Arg->getSourceRange();
6219 Arg = Parens->getSubExpr();
6222 while (SubstNonTypeTemplateParmExpr *subst =
6223 dyn_cast<SubstNonTypeTemplateParmExpr>(Arg))
6224 Arg = subst->getReplacement()->IgnoreImpCasts();
6226 if (UnaryOperator *UnOp = dyn_cast<UnaryOperator>(Arg)) {
6227 if (UnOp->getOpcode() == UO_AddrOf) {
6228 Arg = UnOp->getSubExpr();
6229 AddressTaken = true;
6230 AddrOpLoc = UnOp->getOperatorLoc();
6234 while (SubstNonTypeTemplateParmExpr *subst =
6235 dyn_cast<SubstNonTypeTemplateParmExpr>(Arg))
6236 Arg = subst->getReplacement()->IgnoreImpCasts();
6239 DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Arg);
6240 ValueDecl *Entity = DRE ? DRE->getDecl() : nullptr;
6242 // If our parameter has pointer type, check for a null template value.
6243 if (ParamType->isPointerType() || ParamType->isNullPtrType()) {
6244 switch (isNullPointerValueTemplateArgument(S, Param, ParamType, ArgIn,
6246 case NPV_NullPointer:
6247 S.Diag(Arg->getExprLoc(), diag::warn_cxx98_compat_template_arg_null);
6248 Converted = TemplateArgument(S.Context.getCanonicalType(ParamType),
6249 /*isNullPtr=*/true);
6255 case NPV_NotNullPointer:
6260 // Stop checking the precise nature of the argument if it is value dependent,
6261 // it should be checked when instantiated.
6262 if (Arg->isValueDependent()) {
6263 Converted = TemplateArgument(ArgIn);
6267 if (isa<CXXUuidofExpr>(Arg)) {
6268 if (CheckTemplateArgumentIsCompatibleWithParameter(S, Param, ParamType,
6269 ArgIn, Arg, ArgType))
6272 Converted = TemplateArgument(ArgIn);
6277 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_not_decl_ref)
6278 << Arg->getSourceRange();
6279 S.Diag(Param->getLocation(), diag::note_template_param_here);
6283 // Cannot refer to non-static data members
6284 if (isa<FieldDecl>(Entity) || isa<IndirectFieldDecl>(Entity)) {
6285 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_field)
6286 << Entity << Arg->getSourceRange();
6287 S.Diag(Param->getLocation(), diag::note_template_param_here);
6291 // Cannot refer to non-static member functions
6292 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Entity)) {
6293 if (!Method->isStatic()) {
6294 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_method)
6295 << Method << Arg->getSourceRange();
6296 S.Diag(Param->getLocation(), diag::note_template_param_here);
6301 FunctionDecl *Func = dyn_cast<FunctionDecl>(Entity);
6302 VarDecl *Var = dyn_cast<VarDecl>(Entity);
6304 // A non-type template argument must refer to an object or function.
6305 if (!Func && !Var) {
6306 // We found something, but we don't know specifically what it is.
6307 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_not_object_or_func)
6308 << Arg->getSourceRange();
6309 S.Diag(DRE->getDecl()->getLocation(), diag::note_template_arg_refers_here);
6313 // Address / reference template args must have external linkage in C++98.
6314 if (Entity->getFormalLinkage() == InternalLinkage) {
6315 S.Diag(Arg->getBeginLoc(),
6316 S.getLangOpts().CPlusPlus11
6317 ? diag::warn_cxx98_compat_template_arg_object_internal
6318 : diag::ext_template_arg_object_internal)
6319 << !Func << Entity << Arg->getSourceRange();
6320 S.Diag(Entity->getLocation(), diag::note_template_arg_internal_object)
6322 } else if (!Entity->hasLinkage()) {
6323 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_object_no_linkage)
6324 << !Func << Entity << Arg->getSourceRange();
6325 S.Diag(Entity->getLocation(), diag::note_template_arg_internal_object)
6331 // If the template parameter has pointer type, the function decays.
6332 if (ParamType->isPointerType() && !AddressTaken)
6333 ArgType = S.Context.getPointerType(Func->getType());
6334 else if (AddressTaken && ParamType->isReferenceType()) {
6335 // If we originally had an address-of operator, but the
6336 // parameter has reference type, complain and (if things look
6337 // like they will work) drop the address-of operator.
6338 if (!S.Context.hasSameUnqualifiedType(Func->getType(),
6339 ParamType.getNonReferenceType())) {
6340 S.Diag(AddrOpLoc, diag::err_template_arg_address_of_non_pointer)
6342 S.Diag(Param->getLocation(), diag::note_template_param_here);
6346 S.Diag(AddrOpLoc, diag::err_template_arg_address_of_non_pointer)
6348 << FixItHint::CreateRemoval(AddrOpLoc);
6349 S.Diag(Param->getLocation(), diag::note_template_param_here);
6351 ArgType = Func->getType();
6354 // A value of reference type is not an object.
6355 if (Var->getType()->isReferenceType()) {
6356 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_reference_var)
6357 << Var->getType() << Arg->getSourceRange();
6358 S.Diag(Param->getLocation(), diag::note_template_param_here);
6362 // A template argument must have static storage duration.
6363 if (Var->getTLSKind()) {
6364 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_thread_local)
6365 << Arg->getSourceRange();
6366 S.Diag(Var->getLocation(), diag::note_template_arg_refers_here);
6370 // If the template parameter has pointer type, we must have taken
6371 // the address of this object.
6372 if (ParamType->isReferenceType()) {
6374 // If we originally had an address-of operator, but the
6375 // parameter has reference type, complain and (if things look
6376 // like they will work) drop the address-of operator.
6377 if (!S.Context.hasSameUnqualifiedType(Var->getType(),
6378 ParamType.getNonReferenceType())) {
6379 S.Diag(AddrOpLoc, diag::err_template_arg_address_of_non_pointer)
6381 S.Diag(Param->getLocation(), diag::note_template_param_here);
6385 S.Diag(AddrOpLoc, diag::err_template_arg_address_of_non_pointer)
6387 << FixItHint::CreateRemoval(AddrOpLoc);
6388 S.Diag(Param->getLocation(), diag::note_template_param_here);
6390 ArgType = Var->getType();
6392 } else if (!AddressTaken && ParamType->isPointerType()) {
6393 if (Var->getType()->isArrayType()) {
6394 // Array-to-pointer decay.
6395 ArgType = S.Context.getArrayDecayedType(Var->getType());
6397 // If the template parameter has pointer type but the address of
6398 // this object was not taken, complain and (possibly) recover by
6399 // taking the address of the entity.
6400 ArgType = S.Context.getPointerType(Var->getType());
6401 if (!S.Context.hasSameUnqualifiedType(ArgType, ParamType)) {
6402 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_not_address_of)
6404 S.Diag(Param->getLocation(), diag::note_template_param_here);
6408 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_not_address_of)
6409 << ParamType << FixItHint::CreateInsertion(Arg->getBeginLoc(), "&");
6411 S.Diag(Param->getLocation(), diag::note_template_param_here);
6416 if (CheckTemplateArgumentIsCompatibleWithParameter(S, Param, ParamType, ArgIn,
6420 // Create the template argument.
6422 TemplateArgument(cast<ValueDecl>(Entity->getCanonicalDecl()), ParamType);
6423 S.MarkAnyDeclReferenced(Arg->getBeginLoc(), Entity, false);
6427 /// Checks whether the given template argument is a pointer to
6428 /// member constant according to C++ [temp.arg.nontype]p1.
6429 static bool CheckTemplateArgumentPointerToMember(Sema &S,
6430 NonTypeTemplateParmDecl *Param,
6433 TemplateArgument &Converted) {
6434 bool Invalid = false;
6436 Expr *Arg = ResultArg;
6437 bool ObjCLifetimeConversion;
6439 // C++ [temp.arg.nontype]p1:
6441 // A template-argument for a non-type, non-template
6442 // template-parameter shall be one of: [...]
6444 // -- a pointer to member expressed as described in 5.3.1.
6445 DeclRefExpr *DRE = nullptr;
6447 // In C++98/03 mode, give an extension warning on any extra parentheses.
6448 // See http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#773
6449 bool ExtraParens = false;
6450 while (ParenExpr *Parens = dyn_cast<ParenExpr>(Arg)) {
6451 if (!Invalid && !ExtraParens) {
6452 S.Diag(Arg->getBeginLoc(),
6453 S.getLangOpts().CPlusPlus11
6454 ? diag::warn_cxx98_compat_template_arg_extra_parens
6455 : diag::ext_template_arg_extra_parens)
6456 << Arg->getSourceRange();
6460 Arg = Parens->getSubExpr();
6463 while (SubstNonTypeTemplateParmExpr *subst =
6464 dyn_cast<SubstNonTypeTemplateParmExpr>(Arg))
6465 Arg = subst->getReplacement()->IgnoreImpCasts();
6467 // A pointer-to-member constant written &Class::member.
6468 if (UnaryOperator *UnOp = dyn_cast<UnaryOperator>(Arg)) {
6469 if (UnOp->getOpcode() == UO_AddrOf) {
6470 DRE = dyn_cast<DeclRefExpr>(UnOp->getSubExpr());
6471 if (DRE && !DRE->getQualifier())
6475 // A constant of pointer-to-member type.
6476 else if ((DRE = dyn_cast<DeclRefExpr>(Arg))) {
6477 ValueDecl *VD = DRE->getDecl();
6478 if (VD->getType()->isMemberPointerType()) {
6479 if (isa<NonTypeTemplateParmDecl>(VD)) {
6480 if (Arg->isTypeDependent() || Arg->isValueDependent()) {
6481 Converted = TemplateArgument(Arg);
6483 VD = cast<ValueDecl>(VD->getCanonicalDecl());
6484 Converted = TemplateArgument(VD, ParamType);
6493 ValueDecl *Entity = DRE ? DRE->getDecl() : nullptr;
6495 // Check for a null pointer value.
6496 switch (isNullPointerValueTemplateArgument(S, Param, ParamType, ResultArg,
6500 case NPV_NullPointer:
6501 S.Diag(ResultArg->getExprLoc(), diag::warn_cxx98_compat_template_arg_null);
6502 Converted = TemplateArgument(S.Context.getCanonicalType(ParamType),
6505 case NPV_NotNullPointer:
6509 if (S.IsQualificationConversion(ResultArg->getType(),
6510 ParamType.getNonReferenceType(), false,
6511 ObjCLifetimeConversion)) {
6512 ResultArg = S.ImpCastExprToType(ResultArg, ParamType, CK_NoOp,
6513 ResultArg->getValueKind())
6515 } else if (!S.Context.hasSameUnqualifiedType(
6516 ResultArg->getType(), ParamType.getNonReferenceType())) {
6517 // We can't perform this conversion.
6518 S.Diag(ResultArg->getBeginLoc(), diag::err_template_arg_not_convertible)
6519 << ResultArg->getType() << ParamType << ResultArg->getSourceRange();
6520 S.Diag(Param->getLocation(), diag::note_template_param_here);
6525 return S.Diag(Arg->getBeginLoc(),
6526 diag::err_template_arg_not_pointer_to_member_form)
6527 << Arg->getSourceRange();
6529 if (isa<FieldDecl>(DRE->getDecl()) ||
6530 isa<IndirectFieldDecl>(DRE->getDecl()) ||
6531 isa<CXXMethodDecl>(DRE->getDecl())) {
6532 assert((isa<FieldDecl>(DRE->getDecl()) ||
6533 isa<IndirectFieldDecl>(DRE->getDecl()) ||
6534 !cast<CXXMethodDecl>(DRE->getDecl())->isStatic()) &&
6535 "Only non-static member pointers can make it here");
6537 // Okay: this is the address of a non-static member, and therefore
6538 // a member pointer constant.
6539 if (Arg->isTypeDependent() || Arg->isValueDependent()) {
6540 Converted = TemplateArgument(Arg);
6542 ValueDecl *D = cast<ValueDecl>(DRE->getDecl()->getCanonicalDecl());
6543 Converted = TemplateArgument(D, ParamType);
6548 // We found something else, but we don't know specifically what it is.
6549 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_not_pointer_to_member_form)
6550 << Arg->getSourceRange();
6551 S.Diag(DRE->getDecl()->getLocation(), diag::note_template_arg_refers_here);
6555 /// Check a template argument against its corresponding
6556 /// non-type template parameter.
6558 /// This routine implements the semantics of C++ [temp.arg.nontype].
6559 /// If an error occurred, it returns ExprError(); otherwise, it
6560 /// returns the converted template argument. \p ParamType is the
6561 /// type of the non-type template parameter after it has been instantiated.
6562 ExprResult Sema::CheckTemplateArgument(NonTypeTemplateParmDecl *Param,
6563 QualType ParamType, Expr *Arg,
6564 TemplateArgument &Converted,
6565 CheckTemplateArgumentKind CTAK) {
6566 SourceLocation StartLoc = Arg->getBeginLoc();
6568 // If the parameter type somehow involves auto, deduce the type now.
6569 if (getLangOpts().CPlusPlus17 && ParamType->isUndeducedType()) {
6570 // During template argument deduction, we allow 'decltype(auto)' to
6571 // match an arbitrary dependent argument.
6572 // FIXME: The language rules don't say what happens in this case.
6573 // FIXME: We get an opaque dependent type out of decltype(auto) if the
6574 // expression is merely instantiation-dependent; is this enough?
6575 if (CTAK == CTAK_Deduced && Arg->isTypeDependent()) {
6576 auto *AT = dyn_cast<AutoType>(ParamType);
6577 if (AT && AT->isDecltypeAuto()) {
6578 Converted = TemplateArgument(Arg);
6583 // When checking a deduced template argument, deduce from its type even if
6584 // the type is dependent, in order to check the types of non-type template
6585 // arguments line up properly in partial ordering.
6586 Optional<unsigned> Depth = Param->getDepth() + 1;
6587 Expr *DeductionArg = Arg;
6588 if (auto *PE = dyn_cast<PackExpansionExpr>(DeductionArg))
6589 DeductionArg = PE->getPattern();
6591 Context.getTrivialTypeSourceInfo(ParamType, Param->getLocation()),
6592 DeductionArg, ParamType, Depth,
6593 // We do not check constraints right now because the
6594 // immediately-declared constraint of the auto type is also an
6595 // associated constraint, and will be checked along with the other
6596 // associated constraints after checking the template argument list.
6597 /*IgnoreConstraints=*/true) == DAR_Failed) {
6598 Diag(Arg->getExprLoc(),
6599 diag::err_non_type_template_parm_type_deduction_failure)
6600 << Param->getDeclName() << Param->getType() << Arg->getType()
6601 << Arg->getSourceRange();
6602 Diag(Param->getLocation(), diag::note_template_param_here);
6605 // CheckNonTypeTemplateParameterType will produce a diagnostic if there's
6606 // an error. The error message normally references the parameter
6607 // declaration, but here we'll pass the argument location because that's
6608 // where the parameter type is deduced.
6609 ParamType = CheckNonTypeTemplateParameterType(ParamType, Arg->getExprLoc());
6610 if (ParamType.isNull()) {
6611 Diag(Param->getLocation(), diag::note_template_param_here);
6616 // We should have already dropped all cv-qualifiers by now.
6617 assert(!ParamType.hasQualifiers() &&
6618 "non-type template parameter type cannot be qualified");
6620 if (CTAK == CTAK_Deduced &&
6621 !Context.hasSameType(ParamType.getNonLValueExprType(Context),
6623 // FIXME: If either type is dependent, we skip the check. This isn't
6624 // correct, since during deduction we're supposed to have replaced each
6625 // template parameter with some unique (non-dependent) placeholder.
6626 // FIXME: If the argument type contains 'auto', we carry on and fail the
6627 // type check in order to force specific types to be more specialized than
6628 // 'auto'. It's not clear how partial ordering with 'auto' is supposed to
6630 if ((ParamType->isDependentType() || Arg->isTypeDependent()) &&
6631 !Arg->getType()->getContainedAutoType()) {
6632 Converted = TemplateArgument(Arg);
6635 // FIXME: This attempts to implement C++ [temp.deduct.type]p17. Per DR1770,
6636 // we should actually be checking the type of the template argument in P,
6637 // not the type of the template argument deduced from A, against the
6638 // template parameter type.
6639 Diag(StartLoc, diag::err_deduced_non_type_template_arg_type_mismatch)
6641 << ParamType.getUnqualifiedType();
6642 Diag(Param->getLocation(), diag::note_template_param_here);
6646 // If either the parameter has a dependent type or the argument is
6647 // type-dependent, there's nothing we can check now. The argument only
6648 // contains an unexpanded pack during partial ordering, and there's
6649 // nothing more we can check in that case.
6650 if (ParamType->isDependentType() || Arg->isTypeDependent() ||
6651 Arg->containsUnexpandedParameterPack()) {
6652 // Force the argument to the type of the parameter to maintain invariants.
6653 auto *PE = dyn_cast<PackExpansionExpr>(Arg);
6655 Arg = PE->getPattern();
6656 ExprResult E = ImpCastExprToType(
6657 Arg, ParamType.getNonLValueExprType(Context), CK_Dependent,
6658 ParamType->isLValueReferenceType() ? VK_LValue :
6659 ParamType->isRValueReferenceType() ? VK_XValue : VK_RValue);
6663 // Recreate a pack expansion if we unwrapped one.
6665 PackExpansionExpr(E.get()->getType(), E.get(), PE->getEllipsisLoc(),
6666 PE->getNumExpansions());
6668 Converted = TemplateArgument(E.get());
6672 // The initialization of the parameter from the argument is
6673 // a constant-evaluated context.
6674 EnterExpressionEvaluationContext ConstantEvaluated(
6675 *this, Sema::ExpressionEvaluationContext::ConstantEvaluated);
6677 if (getLangOpts().CPlusPlus17) {
6678 // C++17 [temp.arg.nontype]p1:
6679 // A template-argument for a non-type template parameter shall be
6680 // a converted constant expression of the type of the template-parameter.
6682 ExprResult ArgResult = CheckConvertedConstantExpression(
6683 Arg, ParamType, Value, CCEK_TemplateArg);
6684 if (ArgResult.isInvalid())
6687 // For a value-dependent argument, CheckConvertedConstantExpression is
6688 // permitted (and expected) to be unable to determine a value.
6689 if (ArgResult.get()->isValueDependent()) {
6690 Converted = TemplateArgument(ArgResult.get());
6694 QualType CanonParamType = Context.getCanonicalType(ParamType);
6696 // Convert the APValue to a TemplateArgument.
6697 switch (Value.getKind()) {
6699 assert(ParamType->isNullPtrType());
6700 Converted = TemplateArgument(CanonParamType, /*isNullPtr*/true);
6702 case APValue::Indeterminate:
6703 llvm_unreachable("result of constant evaluation should be initialized");
6706 assert(ParamType->isIntegralOrEnumerationType());
6707 Converted = TemplateArgument(Context, Value.getInt(), CanonParamType);
6709 case APValue::MemberPointer: {
6710 assert(ParamType->isMemberPointerType());
6712 // FIXME: We need TemplateArgument representation and mangling for these.
6713 if (!Value.getMemberPointerPath().empty()) {
6714 Diag(Arg->getBeginLoc(),
6715 diag::err_template_arg_member_ptr_base_derived_not_supported)
6716 << Value.getMemberPointerDecl() << ParamType
6717 << Arg->getSourceRange();
6721 auto *VD = const_cast<ValueDecl*>(Value.getMemberPointerDecl());
6722 Converted = VD ? TemplateArgument(VD, CanonParamType)
6723 : TemplateArgument(CanonParamType, /*isNullPtr*/true);
6726 case APValue::LValue: {
6727 // For a non-type template-parameter of pointer or reference type,
6728 // the value of the constant expression shall not refer to
6729 assert(ParamType->isPointerType() || ParamType->isReferenceType() ||
6730 ParamType->isNullPtrType());
6731 // -- a temporary object
6732 // -- a string literal
6733 // -- the result of a typeid expression, or
6734 // -- a predefined __func__ variable
6735 APValue::LValueBase Base = Value.getLValueBase();
6736 auto *VD = const_cast<ValueDecl *>(Base.dyn_cast<const ValueDecl *>());
6738 auto *E = Base.dyn_cast<const Expr *>();
6739 if (E && isa<CXXUuidofExpr>(E)) {
6740 Converted = TemplateArgument(ArgResult.get()->IgnoreImpCasts());
6743 Diag(Arg->getBeginLoc(), diag::err_template_arg_not_decl_ref)
6744 << Arg->getSourceRange();
6748 if (Value.hasLValuePath() && Value.getLValuePath().size() == 1 &&
6749 VD && VD->getType()->isArrayType() &&
6750 Value.getLValuePath()[0].getAsArrayIndex() == 0 &&
6751 !Value.isLValueOnePastTheEnd() && ParamType->isPointerType()) {
6752 // Per defect report (no number yet):
6753 // ... other than a pointer to the first element of a complete array
6755 } else if (!Value.hasLValuePath() || Value.getLValuePath().size() ||
6756 Value.isLValueOnePastTheEnd()) {
6757 Diag(StartLoc, diag::err_non_type_template_arg_subobject)
6758 << Value.getAsString(Context, ParamType);
6761 assert((VD || !ParamType->isReferenceType()) &&
6762 "null reference should not be a constant expression");
6763 assert((!VD || !ParamType->isNullPtrType()) &&
6764 "non-null value of type nullptr_t?");
6765 Converted = VD ? TemplateArgument(VD, CanonParamType)
6766 : TemplateArgument(CanonParamType, /*isNullPtr*/true);
6769 case APValue::AddrLabelDiff:
6770 return Diag(StartLoc, diag::err_non_type_template_arg_addr_label_diff);
6771 case APValue::FixedPoint:
6772 case APValue::Float:
6773 case APValue::ComplexInt:
6774 case APValue::ComplexFloat:
6775 case APValue::Vector:
6776 case APValue::Array:
6777 case APValue::Struct:
6778 case APValue::Union:
6779 llvm_unreachable("invalid kind for template argument");
6782 return ArgResult.get();
6785 // C++ [temp.arg.nontype]p5:
6786 // The following conversions are performed on each expression used
6787 // as a non-type template-argument. If a non-type
6788 // template-argument cannot be converted to the type of the
6789 // corresponding template-parameter then the program is
6791 if (ParamType->isIntegralOrEnumerationType()) {
6793 // -- for a non-type template-parameter of integral or
6794 // enumeration type, conversions permitted in a converted
6795 // constant expression are applied.
6798 // -- for a non-type template-parameter of integral or
6799 // enumeration type, integral promotions (4.5) and integral
6800 // conversions (4.7) are applied.
6802 if (getLangOpts().CPlusPlus11) {
6803 // C++ [temp.arg.nontype]p1:
6804 // A template-argument for a non-type, non-template template-parameter
6807 // -- for a non-type template-parameter of integral or enumeration
6808 // type, a converted constant expression of the type of the
6809 // template-parameter; or
6811 ExprResult ArgResult =
6812 CheckConvertedConstantExpression(Arg, ParamType, Value,
6814 if (ArgResult.isInvalid())
6817 // We can't check arbitrary value-dependent arguments.
6818 if (ArgResult.get()->isValueDependent()) {
6819 Converted = TemplateArgument(ArgResult.get());
6823 // Widen the argument value to sizeof(parameter type). This is almost
6824 // always a no-op, except when the parameter type is bool. In
6825 // that case, this may extend the argument from 1 bit to 8 bits.
6826 QualType IntegerType = ParamType;
6827 if (const EnumType *Enum = IntegerType->getAs<EnumType>())
6828 IntegerType = Enum->getDecl()->getIntegerType();
6829 Value = Value.extOrTrunc(Context.getTypeSize(IntegerType));
6831 Converted = TemplateArgument(Context, Value,
6832 Context.getCanonicalType(ParamType));
6836 ExprResult ArgResult = DefaultLvalueConversion(Arg);
6837 if (ArgResult.isInvalid())
6839 Arg = ArgResult.get();
6841 QualType ArgType = Arg->getType();
6843 // C++ [temp.arg.nontype]p1:
6844 // A template-argument for a non-type, non-template
6845 // template-parameter shall be one of:
6847 // -- an integral constant-expression of integral or enumeration
6849 // -- the name of a non-type template-parameter; or
6851 if (!ArgType->isIntegralOrEnumerationType()) {
6852 Diag(Arg->getBeginLoc(), diag::err_template_arg_not_integral_or_enumeral)
6853 << ArgType << Arg->getSourceRange();
6854 Diag(Param->getLocation(), diag::note_template_param_here);
6856 } else if (!Arg->isValueDependent()) {
6857 class TmplArgICEDiagnoser : public VerifyICEDiagnoser {
6861 TmplArgICEDiagnoser(QualType T) : T(T) { }
6863 void diagnoseNotICE(Sema &S, SourceLocation Loc,
6864 SourceRange SR) override {
6865 S.Diag(Loc, diag::err_template_arg_not_ice) << T << SR;
6867 } Diagnoser(ArgType);
6869 Arg = VerifyIntegerConstantExpression(Arg, &Value, Diagnoser,
6875 // From here on out, all we care about is the unqualified form
6876 // of the argument type.
6877 ArgType = ArgType.getUnqualifiedType();
6879 // Try to convert the argument to the parameter's type.
6880 if (Context.hasSameType(ParamType, ArgType)) {
6881 // Okay: no conversion necessary
6882 } else if (ParamType->isBooleanType()) {
6883 // This is an integral-to-boolean conversion.
6884 Arg = ImpCastExprToType(Arg, ParamType, CK_IntegralToBoolean).get();
6885 } else if (IsIntegralPromotion(Arg, ArgType, ParamType) ||
6886 !ParamType->isEnumeralType()) {
6887 // This is an integral promotion or conversion.
6888 Arg = ImpCastExprToType(Arg, ParamType, CK_IntegralCast).get();
6890 // We can't perform this conversion.
6891 Diag(Arg->getBeginLoc(), diag::err_template_arg_not_convertible)
6892 << Arg->getType() << ParamType << Arg->getSourceRange();
6893 Diag(Param->getLocation(), diag::note_template_param_here);
6897 // Add the value of this argument to the list of converted
6898 // arguments. We use the bitwidth and signedness of the template
6900 if (Arg->isValueDependent()) {
6901 // The argument is value-dependent. Create a new
6902 // TemplateArgument with the converted expression.
6903 Converted = TemplateArgument(Arg);
6907 QualType IntegerType = Context.getCanonicalType(ParamType);
6908 if (const EnumType *Enum = IntegerType->getAs<EnumType>())
6909 IntegerType = Context.getCanonicalType(Enum->getDecl()->getIntegerType());
6911 if (ParamType->isBooleanType()) {
6912 // Value must be zero or one.
6914 unsigned AllowedBits = Context.getTypeSize(IntegerType);
6915 if (Value.getBitWidth() != AllowedBits)
6916 Value = Value.extOrTrunc(AllowedBits);
6917 Value.setIsSigned(IntegerType->isSignedIntegerOrEnumerationType());
6919 llvm::APSInt OldValue = Value;
6921 // Coerce the template argument's value to the value it will have
6922 // based on the template parameter's type.
6923 unsigned AllowedBits = Context.getTypeSize(IntegerType);
6924 if (Value.getBitWidth() != AllowedBits)
6925 Value = Value.extOrTrunc(AllowedBits);
6926 Value.setIsSigned(IntegerType->isSignedIntegerOrEnumerationType());
6928 // Complain if an unsigned parameter received a negative value.
6929 if (IntegerType->isUnsignedIntegerOrEnumerationType()
6930 && (OldValue.isSigned() && OldValue.isNegative())) {
6931 Diag(Arg->getBeginLoc(), diag::warn_template_arg_negative)
6932 << OldValue.toString(10) << Value.toString(10) << Param->getType()
6933 << Arg->getSourceRange();
6934 Diag(Param->getLocation(), diag::note_template_param_here);
6937 // Complain if we overflowed the template parameter's type.
6938 unsigned RequiredBits;
6939 if (IntegerType->isUnsignedIntegerOrEnumerationType())
6940 RequiredBits = OldValue.getActiveBits();
6941 else if (OldValue.isUnsigned())
6942 RequiredBits = OldValue.getActiveBits() + 1;
6944 RequiredBits = OldValue.getMinSignedBits();
6945 if (RequiredBits > AllowedBits) {
6946 Diag(Arg->getBeginLoc(), diag::warn_template_arg_too_large)
6947 << OldValue.toString(10) << Value.toString(10) << Param->getType()
6948 << Arg->getSourceRange();
6949 Diag(Param->getLocation(), diag::note_template_param_here);
6953 Converted = TemplateArgument(Context, Value,
6954 ParamType->isEnumeralType()
6955 ? Context.getCanonicalType(ParamType)
6960 QualType ArgType = Arg->getType();
6961 DeclAccessPair FoundResult; // temporary for ResolveOverloadedFunction
6963 // Handle pointer-to-function, reference-to-function, and
6964 // pointer-to-member-function all in (roughly) the same way.
6965 if (// -- For a non-type template-parameter of type pointer to
6966 // function, only the function-to-pointer conversion (4.3) is
6967 // applied. If the template-argument represents a set of
6968 // overloaded functions (or a pointer to such), the matching
6969 // function is selected from the set (13.4).
6970 (ParamType->isPointerType() &&
6971 ParamType->castAs<PointerType>()->getPointeeType()->isFunctionType()) ||
6972 // -- For a non-type template-parameter of type reference to
6973 // function, no conversions apply. If the template-argument
6974 // represents a set of overloaded functions, the matching
6975 // function is selected from the set (13.4).
6976 (ParamType->isReferenceType() &&
6977 ParamType->castAs<ReferenceType>()->getPointeeType()->isFunctionType()) ||
6978 // -- For a non-type template-parameter of type pointer to
6979 // member function, no conversions apply. If the
6980 // template-argument represents a set of overloaded member
6981 // functions, the matching member function is selected from
6983 (ParamType->isMemberPointerType() &&
6984 ParamType->castAs<MemberPointerType>()->getPointeeType()
6985 ->isFunctionType())) {
6987 if (Arg->getType() == Context.OverloadTy) {
6988 if (FunctionDecl *Fn = ResolveAddressOfOverloadedFunction(Arg, ParamType,
6991 if (DiagnoseUseOfDecl(Fn, Arg->getBeginLoc()))
6994 Arg = FixOverloadedFunctionReference(Arg, FoundResult, Fn);
6995 ArgType = Arg->getType();
7000 if (!ParamType->isMemberPointerType()) {
7001 if (CheckTemplateArgumentAddressOfObjectOrFunction(*this, Param,
7008 if (CheckTemplateArgumentPointerToMember(*this, Param, ParamType, Arg,
7014 if (ParamType->isPointerType()) {
7015 // -- for a non-type template-parameter of type pointer to
7016 // object, qualification conversions (4.4) and the
7017 // array-to-pointer conversion (4.2) are applied.
7018 // C++0x also allows a value of std::nullptr_t.
7019 assert(ParamType->getPointeeType()->isIncompleteOrObjectType() &&
7020 "Only object pointers allowed here");
7022 if (CheckTemplateArgumentAddressOfObjectOrFunction(*this, Param,
7029 if (const ReferenceType *ParamRefType = ParamType->getAs<ReferenceType>()) {
7030 // -- For a non-type template-parameter of type reference to
7031 // object, no conversions apply. The type referred to by the
7032 // reference may be more cv-qualified than the (otherwise
7033 // identical) type of the template-argument. The
7034 // template-parameter is bound directly to the
7035 // template-argument, which must be an lvalue.
7036 assert(ParamRefType->getPointeeType()->isIncompleteOrObjectType() &&
7037 "Only object references allowed here");
7039 if (Arg->getType() == Context.OverloadTy) {
7040 if (FunctionDecl *Fn = ResolveAddressOfOverloadedFunction(Arg,
7041 ParamRefType->getPointeeType(),
7044 if (DiagnoseUseOfDecl(Fn, Arg->getBeginLoc()))
7047 Arg = FixOverloadedFunctionReference(Arg, FoundResult, Fn);
7048 ArgType = Arg->getType();
7053 if (CheckTemplateArgumentAddressOfObjectOrFunction(*this, Param,
7060 // Deal with parameters of type std::nullptr_t.
7061 if (ParamType->isNullPtrType()) {
7062 if (Arg->isTypeDependent() || Arg->isValueDependent()) {
7063 Converted = TemplateArgument(Arg);
7067 switch (isNullPointerValueTemplateArgument(*this, Param, ParamType, Arg)) {
7068 case NPV_NotNullPointer:
7069 Diag(Arg->getExprLoc(), diag::err_template_arg_not_convertible)
7070 << Arg->getType() << ParamType;
7071 Diag(Param->getLocation(), diag::note_template_param_here);
7077 case NPV_NullPointer:
7078 Diag(Arg->getExprLoc(), diag::warn_cxx98_compat_template_arg_null);
7079 Converted = TemplateArgument(Context.getCanonicalType(ParamType),
7085 // -- For a non-type template-parameter of type pointer to data
7086 // member, qualification conversions (4.4) are applied.
7087 assert(ParamType->isMemberPointerType() && "Only pointers to members remain");
7089 if (CheckTemplateArgumentPointerToMember(*this, Param, ParamType, Arg,
7095 static void DiagnoseTemplateParameterListArityMismatch(
7096 Sema &S, TemplateParameterList *New, TemplateParameterList *Old,
7097 Sema::TemplateParameterListEqualKind Kind, SourceLocation TemplateArgLoc);
7099 /// Check a template argument against its corresponding
7100 /// template template parameter.
7102 /// This routine implements the semantics of C++ [temp.arg.template].
7103 /// It returns true if an error occurred, and false otherwise.
7104 bool Sema::CheckTemplateTemplateArgument(TemplateTemplateParmDecl *Param,
7105 TemplateParameterList *Params,
7106 TemplateArgumentLoc &Arg) {
7107 TemplateName Name = Arg.getArgument().getAsTemplateOrTemplatePattern();
7108 TemplateDecl *Template = Name.getAsTemplateDecl();
7110 // Any dependent template name is fine.
7111 assert(Name.isDependent() && "Non-dependent template isn't a declaration?");
7115 if (Template->isInvalidDecl())
7118 // C++0x [temp.arg.template]p1:
7119 // A template-argument for a template template-parameter shall be
7120 // the name of a class template or an alias template, expressed as an
7121 // id-expression. When the template-argument names a class template, only
7122 // primary class templates are considered when matching the
7123 // template template argument with the corresponding parameter;
7124 // partial specializations are not considered even if their
7125 // parameter lists match that of the template template parameter.
7127 // Note that we also allow template template parameters here, which
7128 // will happen when we are dealing with, e.g., class template
7129 // partial specializations.
7130 if (!isa<ClassTemplateDecl>(Template) &&
7131 !isa<TemplateTemplateParmDecl>(Template) &&
7132 !isa<TypeAliasTemplateDecl>(Template) &&
7133 !isa<BuiltinTemplateDecl>(Template)) {
7134 assert(isa<FunctionTemplateDecl>(Template) &&
7135 "Only function templates are possible here");
7136 Diag(Arg.getLocation(), diag::err_template_arg_not_valid_template);
7137 Diag(Template->getLocation(), diag::note_template_arg_refers_here_func)
7141 // C++1z [temp.arg.template]p3: (DR 150)
7142 // A template-argument matches a template template-parameter P when P
7143 // is at least as specialized as the template-argument A.
7144 // FIXME: We should enable RelaxedTemplateTemplateArgs by default as it is a
7145 // defect report resolution from C++17 and shouldn't be introduced by
7147 if (getLangOpts().RelaxedTemplateTemplateArgs) {
7148 // Quick check for the common case:
7149 // If P contains a parameter pack, then A [...] matches P if each of A's
7150 // template parameters matches the corresponding template parameter in
7151 // the template-parameter-list of P.
7152 if (TemplateParameterListsAreEqual(
7153 Template->getTemplateParameters(), Params, false,
7154 TPL_TemplateTemplateArgumentMatch, Arg.getLocation()) &&
7155 // If the argument has no associated constraints, then the parameter is
7156 // definitely at least as specialized as the argument.
7157 // Otherwise - we need a more thorough check.
7158 !Template->hasAssociatedConstraints())
7161 if (isTemplateTemplateParameterAtLeastAsSpecializedAs(Params, Template,
7162 Arg.getLocation())) {
7163 // C++2a[temp.func.order]p2
7164 // [...] If both deductions succeed, the partial ordering selects the
7165 // more constrained template as described by the rules in
7166 // [temp.constr.order].
7167 SmallVector<const Expr *, 3> ParamsAC, TemplateAC;
7168 Params->getAssociatedConstraints(ParamsAC);
7169 // C++2a[temp.arg.template]p3
7170 // [...] In this comparison, if P is unconstrained, the constraints on A
7171 // are not considered.
7172 if (ParamsAC.empty())
7174 Template->getAssociatedConstraints(TemplateAC);
7175 bool IsParamAtLeastAsConstrained;
7176 if (IsAtLeastAsConstrained(Param, ParamsAC, Template, TemplateAC,
7177 IsParamAtLeastAsConstrained))
7179 if (!IsParamAtLeastAsConstrained) {
7180 Diag(Arg.getLocation(),
7181 diag::err_template_template_parameter_not_at_least_as_constrained)
7182 << Template << Param << Arg.getSourceRange();
7183 Diag(Param->getLocation(), diag::note_entity_declared_at) << Param;
7184 Diag(Template->getLocation(), diag::note_entity_declared_at)
7186 MaybeEmitAmbiguousAtomicConstraintsDiagnostic(Param, ParamsAC, Template,
7192 // FIXME: Produce better diagnostics for deduction failures.
7195 return !TemplateParameterListsAreEqual(Template->getTemplateParameters(),
7198 TPL_TemplateTemplateArgumentMatch,
7202 /// Given a non-type template argument that refers to a
7203 /// declaration and the type of its corresponding non-type template
7204 /// parameter, produce an expression that properly refers to that
7207 Sema::BuildExpressionFromDeclTemplateArgument(const TemplateArgument &Arg,
7209 SourceLocation Loc) {
7210 // C++ [temp.param]p8:
7212 // A non-type template-parameter of type "array of T" or
7213 // "function returning T" is adjusted to be of type "pointer to
7214 // T" or "pointer to function returning T", respectively.
7215 if (ParamType->isArrayType())
7216 ParamType = Context.getArrayDecayedType(ParamType);
7217 else if (ParamType->isFunctionType())
7218 ParamType = Context.getPointerType(ParamType);
7220 // For a NULL non-type template argument, return nullptr casted to the
7221 // parameter's type.
7222 if (Arg.getKind() == TemplateArgument::NullPtr) {
7223 return ImpCastExprToType(
7224 new (Context) CXXNullPtrLiteralExpr(Context.NullPtrTy, Loc),
7226 ParamType->getAs<MemberPointerType>()
7227 ? CK_NullToMemberPointer
7228 : CK_NullToPointer);
7230 assert(Arg.getKind() == TemplateArgument::Declaration &&
7231 "Only declaration template arguments permitted here");
7233 ValueDecl *VD = Arg.getAsDecl();
7236 if (ParamType->isMemberPointerType()) {
7237 // If this is a pointer to member, we need to use a qualified name to
7238 // form a suitable pointer-to-member constant.
7239 assert(VD->getDeclContext()->isRecord() &&
7240 (isa<CXXMethodDecl>(VD) || isa<FieldDecl>(VD) ||
7241 isa<IndirectFieldDecl>(VD)));
7243 = Context.getTypeDeclType(cast<RecordDecl>(VD->getDeclContext()));
7244 NestedNameSpecifier *Qualifier
7245 = NestedNameSpecifier::Create(Context, nullptr, false,
7246 ClassType.getTypePtr());
7247 SS.MakeTrivial(Context, Qualifier, Loc);
7250 ExprResult RefExpr = BuildDeclarationNameExpr(
7251 SS, DeclarationNameInfo(VD->getDeclName(), Loc), VD);
7252 if (RefExpr.isInvalid())
7255 // For a pointer, the argument declaration is the pointee. Take its address.
7256 QualType ElemT(RefExpr.get()->getType()->getArrayElementTypeNoTypeQual(), 0);
7257 if (ParamType->isPointerType() && !ElemT.isNull() &&
7258 Context.hasSimilarType(ElemT, ParamType->getPointeeType())) {
7259 // Decay an array argument if we want a pointer to its first element.
7260 RefExpr = DefaultFunctionArrayConversion(RefExpr.get());
7261 if (RefExpr.isInvalid())
7263 } else if (ParamType->isPointerType() || ParamType->isMemberPointerType()) {
7264 // For any other pointer, take the address (or form a pointer-to-member).
7265 RefExpr = CreateBuiltinUnaryOp(Loc, UO_AddrOf, RefExpr.get());
7266 if (RefExpr.isInvalid())
7269 assert(ParamType->isReferenceType() &&
7270 "unexpected type for decl template argument");
7273 // At this point we should have the right value category.
7274 assert(ParamType->isReferenceType() == RefExpr.get()->isLValue() &&
7275 "value kind mismatch for non-type template argument");
7277 // The type of the template parameter can differ from the type of the
7278 // argument in various ways; convert it now if necessary.
7279 QualType DestExprType = ParamType.getNonLValueExprType(Context);
7280 if (!Context.hasSameType(RefExpr.get()->getType(), DestExprType)) {
7283 if (Context.hasSimilarType(RefExpr.get()->getType(), DestExprType) ||
7284 IsFunctionConversion(RefExpr.get()->getType(), DestExprType, Ignored)) {
7286 } else if (ParamType->isVoidPointerType() &&
7287 RefExpr.get()->getType()->isPointerType()) {
7290 // FIXME: Pointers to members can need conversion derived-to-base or
7291 // base-to-derived conversions. We currently don't retain enough
7292 // information to convert properly (we need to track a cast path or
7293 // subobject number in the template argument).
7295 "unexpected conversion required for non-type template argument");
7297 RefExpr = ImpCastExprToType(RefExpr.get(), DestExprType, CK,
7298 RefExpr.get()->getValueKind());
7304 /// Construct a new expression that refers to the given
7305 /// integral template argument with the given source-location
7308 /// This routine takes care of the mapping from an integral template
7309 /// argument (which may have any integral type) to the appropriate
7312 Sema::BuildExpressionFromIntegralTemplateArgument(const TemplateArgument &Arg,
7313 SourceLocation Loc) {
7314 assert(Arg.getKind() == TemplateArgument::Integral &&
7315 "Operation is only valid for integral template arguments");
7316 QualType OrigT = Arg.getIntegralType();
7318 // If this is an enum type that we're instantiating, we need to use an integer
7319 // type the same size as the enumerator. We don't want to build an
7320 // IntegerLiteral with enum type. The integer type of an enum type can be of
7321 // any integral type with C++11 enum classes, make sure we create the right
7322 // type of literal for it.
7324 if (const EnumType *ET = OrigT->getAs<EnumType>())
7325 T = ET->getDecl()->getIntegerType();
7328 if (T->isAnyCharacterType()) {
7329 CharacterLiteral::CharacterKind Kind;
7330 if (T->isWideCharType())
7331 Kind = CharacterLiteral::Wide;
7332 else if (T->isChar8Type() && getLangOpts().Char8)
7333 Kind = CharacterLiteral::UTF8;
7334 else if (T->isChar16Type())
7335 Kind = CharacterLiteral::UTF16;
7336 else if (T->isChar32Type())
7337 Kind = CharacterLiteral::UTF32;
7339 Kind = CharacterLiteral::Ascii;
7341 E = new (Context) CharacterLiteral(Arg.getAsIntegral().getZExtValue(),
7343 } else if (T->isBooleanType()) {
7344 E = new (Context) CXXBoolLiteralExpr(Arg.getAsIntegral().getBoolValue(),
7346 } else if (T->isNullPtrType()) {
7347 E = new (Context) CXXNullPtrLiteralExpr(Context.NullPtrTy, Loc);
7349 E = IntegerLiteral::Create(Context, Arg.getAsIntegral(), T, Loc);
7352 if (OrigT->isEnumeralType()) {
7353 // FIXME: This is a hack. We need a better way to handle substituted
7354 // non-type template parameters.
7355 E = CStyleCastExpr::Create(Context, OrigT, VK_RValue, CK_IntegralCast, E,
7357 Context.getTrivialTypeSourceInfo(OrigT, Loc),
7364 /// Match two template parameters within template parameter lists.
7365 static bool MatchTemplateParameterKind(Sema &S, NamedDecl *New, NamedDecl *Old,
7367 Sema::TemplateParameterListEqualKind Kind,
7368 SourceLocation TemplateArgLoc) {
7369 // Check the actual kind (type, non-type, template).
7370 if (Old->getKind() != New->getKind()) {
7372 unsigned NextDiag = diag::err_template_param_different_kind;
7373 if (TemplateArgLoc.isValid()) {
7374 S.Diag(TemplateArgLoc, diag::err_template_arg_template_params_mismatch);
7375 NextDiag = diag::note_template_param_different_kind;
7377 S.Diag(New->getLocation(), NextDiag)
7378 << (Kind != Sema::TPL_TemplateMatch);
7379 S.Diag(Old->getLocation(), diag::note_template_prev_declaration)
7380 << (Kind != Sema::TPL_TemplateMatch);
7386 // Check that both are parameter packs or neither are parameter packs.
7387 // However, if we are matching a template template argument to a
7388 // template template parameter, the template template parameter can have
7389 // a parameter pack where the template template argument does not.
7390 if (Old->isTemplateParameterPack() != New->isTemplateParameterPack() &&
7391 !(Kind == Sema::TPL_TemplateTemplateArgumentMatch &&
7392 Old->isTemplateParameterPack())) {
7394 unsigned NextDiag = diag::err_template_parameter_pack_non_pack;
7395 if (TemplateArgLoc.isValid()) {
7396 S.Diag(TemplateArgLoc,
7397 diag::err_template_arg_template_params_mismatch);
7398 NextDiag = diag::note_template_parameter_pack_non_pack;
7401 unsigned ParamKind = isa<TemplateTypeParmDecl>(New)? 0
7402 : isa<NonTypeTemplateParmDecl>(New)? 1
7404 S.Diag(New->getLocation(), NextDiag)
7405 << ParamKind << New->isParameterPack();
7406 S.Diag(Old->getLocation(), diag::note_template_parameter_pack_here)
7407 << ParamKind << Old->isParameterPack();
7413 // For non-type template parameters, check the type of the parameter.
7414 if (NonTypeTemplateParmDecl *OldNTTP
7415 = dyn_cast<NonTypeTemplateParmDecl>(Old)) {
7416 NonTypeTemplateParmDecl *NewNTTP = cast<NonTypeTemplateParmDecl>(New);
7418 // If we are matching a template template argument to a template
7419 // template parameter and one of the non-type template parameter types
7420 // is dependent, then we must wait until template instantiation time
7421 // to actually compare the arguments.
7422 if (Kind != Sema::TPL_TemplateTemplateArgumentMatch ||
7423 (!OldNTTP->getType()->isDependentType() &&
7424 !NewNTTP->getType()->isDependentType()))
7425 if (!S.Context.hasSameType(OldNTTP->getType(), NewNTTP->getType())) {
7427 unsigned NextDiag = diag::err_template_nontype_parm_different_type;
7428 if (TemplateArgLoc.isValid()) {
7429 S.Diag(TemplateArgLoc,
7430 diag::err_template_arg_template_params_mismatch);
7431 NextDiag = diag::note_template_nontype_parm_different_type;
7433 S.Diag(NewNTTP->getLocation(), NextDiag)
7434 << NewNTTP->getType()
7435 << (Kind != Sema::TPL_TemplateMatch);
7436 S.Diag(OldNTTP->getLocation(),
7437 diag::note_template_nontype_parm_prev_declaration)
7438 << OldNTTP->getType();
7444 // For template template parameters, check the template parameter types.
7445 // The template parameter lists of template template
7446 // parameters must agree.
7447 else if (TemplateTemplateParmDecl *OldTTP
7448 = dyn_cast<TemplateTemplateParmDecl>(Old)) {
7449 TemplateTemplateParmDecl *NewTTP = cast<TemplateTemplateParmDecl>(New);
7450 if (!S.TemplateParameterListsAreEqual(NewTTP->getTemplateParameters(),
7451 OldTTP->getTemplateParameters(),
7453 (Kind == Sema::TPL_TemplateMatch
7454 ? Sema::TPL_TemplateTemplateParmMatch
7458 } else if (Kind != Sema::TPL_TemplateTemplateArgumentMatch) {
7459 const Expr *NewC = nullptr, *OldC = nullptr;
7460 if (const auto *TC = cast<TemplateTypeParmDecl>(New)->getTypeConstraint())
7461 NewC = TC->getImmediatelyDeclaredConstraint();
7462 if (const auto *TC = cast<TemplateTypeParmDecl>(Old)->getTypeConstraint())
7463 OldC = TC->getImmediatelyDeclaredConstraint();
7465 auto Diagnose = [&] {
7466 S.Diag(NewC ? NewC->getBeginLoc() : New->getBeginLoc(),
7467 diag::err_template_different_type_constraint);
7468 S.Diag(OldC ? OldC->getBeginLoc() : Old->getBeginLoc(),
7469 diag::note_template_prev_declaration) << /*declaration*/0;
7472 if (!NewC != !OldC) {
7479 llvm::FoldingSetNodeID OldCID, NewCID;
7480 OldC->Profile(OldCID, S.Context, /*Canonical=*/true);
7481 NewC->Profile(NewCID, S.Context, /*Canonical=*/true);
7482 if (OldCID != NewCID) {
7493 /// Diagnose a known arity mismatch when comparing template argument
7496 void DiagnoseTemplateParameterListArityMismatch(Sema &S,
7497 TemplateParameterList *New,
7498 TemplateParameterList *Old,
7499 Sema::TemplateParameterListEqualKind Kind,
7500 SourceLocation TemplateArgLoc) {
7501 unsigned NextDiag = diag::err_template_param_list_different_arity;
7502 if (TemplateArgLoc.isValid()) {
7503 S.Diag(TemplateArgLoc, diag::err_template_arg_template_params_mismatch);
7504 NextDiag = diag::note_template_param_list_different_arity;
7506 S.Diag(New->getTemplateLoc(), NextDiag)
7507 << (New->size() > Old->size())
7508 << (Kind != Sema::TPL_TemplateMatch)
7509 << SourceRange(New->getTemplateLoc(), New->getRAngleLoc());
7510 S.Diag(Old->getTemplateLoc(), diag::note_template_prev_declaration)
7511 << (Kind != Sema::TPL_TemplateMatch)
7512 << SourceRange(Old->getTemplateLoc(), Old->getRAngleLoc());
7515 /// Determine whether the given template parameter lists are
7518 /// \param New The new template parameter list, typically written in the
7519 /// source code as part of a new template declaration.
7521 /// \param Old The old template parameter list, typically found via
7522 /// name lookup of the template declared with this template parameter
7525 /// \param Complain If true, this routine will produce a diagnostic if
7526 /// the template parameter lists are not equivalent.
7528 /// \param Kind describes how we are to match the template parameter lists.
7530 /// \param TemplateArgLoc If this source location is valid, then we
7531 /// are actually checking the template parameter list of a template
7532 /// argument (New) against the template parameter list of its
7533 /// corresponding template template parameter (Old). We produce
7534 /// slightly different diagnostics in this scenario.
7536 /// \returns True if the template parameter lists are equal, false
7539 Sema::TemplateParameterListsAreEqual(TemplateParameterList *New,
7540 TemplateParameterList *Old,
7542 TemplateParameterListEqualKind Kind,
7543 SourceLocation TemplateArgLoc) {
7544 if (Old->size() != New->size() && Kind != TPL_TemplateTemplateArgumentMatch) {
7546 DiagnoseTemplateParameterListArityMismatch(*this, New, Old, Kind,
7552 // C++0x [temp.arg.template]p3:
7553 // A template-argument matches a template template-parameter (call it P)
7554 // when each of the template parameters in the template-parameter-list of
7555 // the template-argument's corresponding class template or alias template
7556 // (call it A) matches the corresponding template parameter in the
7557 // template-parameter-list of P. [...]
7558 TemplateParameterList::iterator NewParm = New->begin();
7559 TemplateParameterList::iterator NewParmEnd = New->end();
7560 for (TemplateParameterList::iterator OldParm = Old->begin(),
7561 OldParmEnd = Old->end();
7562 OldParm != OldParmEnd; ++OldParm) {
7563 if (Kind != TPL_TemplateTemplateArgumentMatch ||
7564 !(*OldParm)->isTemplateParameterPack()) {
7565 if (NewParm == NewParmEnd) {
7567 DiagnoseTemplateParameterListArityMismatch(*this, New, Old, Kind,
7573 if (!MatchTemplateParameterKind(*this, *NewParm, *OldParm, Complain,
7574 Kind, TemplateArgLoc))
7581 // C++0x [temp.arg.template]p3:
7582 // [...] When P's template- parameter-list contains a template parameter
7583 // pack (14.5.3), the template parameter pack will match zero or more
7584 // template parameters or template parameter packs in the
7585 // template-parameter-list of A with the same type and form as the
7586 // template parameter pack in P (ignoring whether those template
7587 // parameters are template parameter packs).
7588 for (; NewParm != NewParmEnd; ++NewParm) {
7589 if (!MatchTemplateParameterKind(*this, *NewParm, *OldParm, Complain,
7590 Kind, TemplateArgLoc))
7595 // Make sure we exhausted all of the arguments.
7596 if (NewParm != NewParmEnd) {
7598 DiagnoseTemplateParameterListArityMismatch(*this, New, Old, Kind,
7604 if (Kind != TPL_TemplateTemplateArgumentMatch) {
7605 const Expr *NewRC = New->getRequiresClause();
7606 const Expr *OldRC = Old->getRequiresClause();
7608 auto Diagnose = [&] {
7609 Diag(NewRC ? NewRC->getBeginLoc() : New->getTemplateLoc(),
7610 diag::err_template_different_requires_clause);
7611 Diag(OldRC ? OldRC->getBeginLoc() : Old->getTemplateLoc(),
7612 diag::note_template_prev_declaration) << /*declaration*/0;
7615 if (!NewRC != !OldRC) {
7622 llvm::FoldingSetNodeID OldRCID, NewRCID;
7623 OldRC->Profile(OldRCID, Context, /*Canonical=*/true);
7624 NewRC->Profile(NewRCID, Context, /*Canonical=*/true);
7625 if (OldRCID != NewRCID) {
7636 /// Check whether a template can be declared within this scope.
7638 /// If the template declaration is valid in this scope, returns
7639 /// false. Otherwise, issues a diagnostic and returns true.
7641 Sema::CheckTemplateDeclScope(Scope *S, TemplateParameterList *TemplateParams) {
7645 // Find the nearest enclosing declaration scope.
7646 while ((S->getFlags() & Scope::DeclScope) == 0 ||
7647 (S->getFlags() & Scope::TemplateParamScope) != 0)
7651 // A template [...] shall not have C linkage.
7652 DeclContext *Ctx = S->getEntity();
7653 assert(Ctx && "Unknown context");
7654 if (Ctx->isExternCContext()) {
7655 Diag(TemplateParams->getTemplateLoc(), diag::err_template_linkage)
7656 << TemplateParams->getSourceRange();
7657 if (const LinkageSpecDecl *LSD = Ctx->getExternCContext())
7658 Diag(LSD->getExternLoc(), diag::note_extern_c_begins_here);
7661 Ctx = Ctx->getRedeclContext();
7664 // A template-declaration can appear only as a namespace scope or
7665 // class scope declaration.
7667 if (Ctx->isFileContext())
7669 if (CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(Ctx)) {
7670 // C++ [temp.mem]p2:
7671 // A local class shall not have member templates.
7672 if (RD->isLocalClass())
7673 return Diag(TemplateParams->getTemplateLoc(),
7674 diag::err_template_inside_local_class)
7675 << TemplateParams->getSourceRange();
7681 return Diag(TemplateParams->getTemplateLoc(),
7682 diag::err_template_outside_namespace_or_class_scope)
7683 << TemplateParams->getSourceRange();
7686 /// Determine what kind of template specialization the given declaration
7688 static TemplateSpecializationKind getTemplateSpecializationKind(Decl *D) {
7690 return TSK_Undeclared;
7692 if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(D))
7693 return Record->getTemplateSpecializationKind();
7694 if (FunctionDecl *Function = dyn_cast<FunctionDecl>(D))
7695 return Function->getTemplateSpecializationKind();
7696 if (VarDecl *Var = dyn_cast<VarDecl>(D))
7697 return Var->getTemplateSpecializationKind();
7699 return TSK_Undeclared;
7702 /// Check whether a specialization is well-formed in the current
7705 /// This routine determines whether a template specialization can be declared
7706 /// in the current context (C++ [temp.expl.spec]p2).
7708 /// \param S the semantic analysis object for which this check is being
7711 /// \param Specialized the entity being specialized or instantiated, which
7712 /// may be a kind of template (class template, function template, etc.) or
7713 /// a member of a class template (member function, static data member,
7716 /// \param PrevDecl the previous declaration of this entity, if any.
7718 /// \param Loc the location of the explicit specialization or instantiation of
7721 /// \param IsPartialSpecialization whether this is a partial specialization of
7722 /// a class template.
7724 /// \returns true if there was an error that we cannot recover from, false
7726 static bool CheckTemplateSpecializationScope(Sema &S,
7727 NamedDecl *Specialized,
7728 NamedDecl *PrevDecl,
7730 bool IsPartialSpecialization) {
7731 // Keep these "kind" numbers in sync with the %select statements in the
7732 // various diagnostics emitted by this routine.
7734 if (isa<ClassTemplateDecl>(Specialized))
7735 EntityKind = IsPartialSpecialization? 1 : 0;
7736 else if (isa<VarTemplateDecl>(Specialized))
7737 EntityKind = IsPartialSpecialization ? 3 : 2;
7738 else if (isa<FunctionTemplateDecl>(Specialized))
7740 else if (isa<CXXMethodDecl>(Specialized))
7742 else if (isa<VarDecl>(Specialized))
7744 else if (isa<RecordDecl>(Specialized))
7746 else if (isa<EnumDecl>(Specialized) && S.getLangOpts().CPlusPlus11)
7749 S.Diag(Loc, diag::err_template_spec_unknown_kind)
7750 << S.getLangOpts().CPlusPlus11;
7751 S.Diag(Specialized->getLocation(), diag::note_specialized_entity);
7755 // C++ [temp.expl.spec]p2:
7756 // An explicit specialization may be declared in any scope in which
7757 // the corresponding primary template may be defined.
7758 if (S.CurContext->getRedeclContext()->isFunctionOrMethod()) {
7759 S.Diag(Loc, diag::err_template_spec_decl_function_scope)
7764 // C++ [temp.class.spec]p6:
7765 // A class template partial specialization may be declared in any
7766 // scope in which the primary template may be defined.
7767 DeclContext *SpecializedContext =
7768 Specialized->getDeclContext()->getRedeclContext();
7769 DeclContext *DC = S.CurContext->getRedeclContext();
7771 // Make sure that this redeclaration (or definition) occurs in the same
7772 // scope or an enclosing namespace.
7773 if (!(DC->isFileContext() ? DC->Encloses(SpecializedContext)
7774 : DC->Equals(SpecializedContext))) {
7775 if (isa<TranslationUnitDecl>(SpecializedContext))
7776 S.Diag(Loc, diag::err_template_spec_redecl_global_scope)
7777 << EntityKind << Specialized;
7779 auto *ND = cast<NamedDecl>(SpecializedContext);
7780 int Diag = diag::err_template_spec_redecl_out_of_scope;
7781 if (S.getLangOpts().MicrosoftExt && !DC->isRecord())
7782 Diag = diag::ext_ms_template_spec_redecl_out_of_scope;
7783 S.Diag(Loc, Diag) << EntityKind << Specialized
7784 << ND << isa<CXXRecordDecl>(ND);
7787 S.Diag(Specialized->getLocation(), diag::note_specialized_entity);
7789 // Don't allow specializing in the wrong class during error recovery.
7790 // Otherwise, things can go horribly wrong.
7798 static SourceRange findTemplateParameterInType(unsigned Depth, Expr *E) {
7799 if (!E->isTypeDependent())
7800 return SourceLocation();
7801 DependencyChecker Checker(Depth, /*IgnoreNonTypeDependent*/true);
7802 Checker.TraverseStmt(E);
7803 if (Checker.MatchLoc.isInvalid())
7804 return E->getSourceRange();
7805 return Checker.MatchLoc;
7808 static SourceRange findTemplateParameter(unsigned Depth, TypeLoc TL) {
7809 if (!TL.getType()->isDependentType())
7810 return SourceLocation();
7811 DependencyChecker Checker(Depth, /*IgnoreNonTypeDependent*/true);
7812 Checker.TraverseTypeLoc(TL);
7813 if (Checker.MatchLoc.isInvalid())
7814 return TL.getSourceRange();
7815 return Checker.MatchLoc;
7818 /// Subroutine of Sema::CheckTemplatePartialSpecializationArgs
7819 /// that checks non-type template partial specialization arguments.
7820 static bool CheckNonTypeTemplatePartialSpecializationArgs(
7821 Sema &S, SourceLocation TemplateNameLoc, NonTypeTemplateParmDecl *Param,
7822 const TemplateArgument *Args, unsigned NumArgs, bool IsDefaultArgument) {
7823 for (unsigned I = 0; I != NumArgs; ++I) {
7824 if (Args[I].getKind() == TemplateArgument::Pack) {
7825 if (CheckNonTypeTemplatePartialSpecializationArgs(
7826 S, TemplateNameLoc, Param, Args[I].pack_begin(),
7827 Args[I].pack_size(), IsDefaultArgument))
7833 if (Args[I].getKind() != TemplateArgument::Expression)
7836 Expr *ArgExpr = Args[I].getAsExpr();
7838 // We can have a pack expansion of any of the bullets below.
7839 if (PackExpansionExpr *Expansion = dyn_cast<PackExpansionExpr>(ArgExpr))
7840 ArgExpr = Expansion->getPattern();
7842 // Strip off any implicit casts we added as part of type checking.
7843 while (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(ArgExpr))
7844 ArgExpr = ICE->getSubExpr();
7846 // C++ [temp.class.spec]p8:
7847 // A non-type argument is non-specialized if it is the name of a
7848 // non-type parameter. All other non-type arguments are
7851 // Below, we check the two conditions that only apply to
7852 // specialized non-type arguments, so skip any non-specialized
7854 if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(ArgExpr))
7855 if (isa<NonTypeTemplateParmDecl>(DRE->getDecl()))
7858 // C++ [temp.class.spec]p9:
7859 // Within the argument list of a class template partial
7860 // specialization, the following restrictions apply:
7861 // -- A partially specialized non-type argument expression
7862 // shall not involve a template parameter of the partial
7863 // specialization except when the argument expression is a
7864 // simple identifier.
7865 // -- The type of a template parameter corresponding to a
7866 // specialized non-type argument shall not be dependent on a
7867 // parameter of the specialization.
7868 // DR1315 removes the first bullet, leaving an incoherent set of rules.
7869 // We implement a compromise between the original rules and DR1315:
7870 // -- A specialized non-type template argument shall not be
7871 // type-dependent and the corresponding template parameter
7872 // shall have a non-dependent type.
7873 SourceRange ParamUseRange =
7874 findTemplateParameterInType(Param->getDepth(), ArgExpr);
7875 if (ParamUseRange.isValid()) {
7876 if (IsDefaultArgument) {
7877 S.Diag(TemplateNameLoc,
7878 diag::err_dependent_non_type_arg_in_partial_spec);
7879 S.Diag(ParamUseRange.getBegin(),
7880 diag::note_dependent_non_type_default_arg_in_partial_spec)
7883 S.Diag(ParamUseRange.getBegin(),
7884 diag::err_dependent_non_type_arg_in_partial_spec)
7890 ParamUseRange = findTemplateParameter(
7891 Param->getDepth(), Param->getTypeSourceInfo()->getTypeLoc());
7892 if (ParamUseRange.isValid()) {
7893 S.Diag(IsDefaultArgument ? TemplateNameLoc : ArgExpr->getBeginLoc(),
7894 diag::err_dependent_typed_non_type_arg_in_partial_spec)
7895 << Param->getType();
7896 S.Diag(Param->getLocation(), diag::note_template_param_here)
7897 << (IsDefaultArgument ? ParamUseRange : SourceRange())
7906 /// Check the non-type template arguments of a class template
7907 /// partial specialization according to C++ [temp.class.spec]p9.
7909 /// \param TemplateNameLoc the location of the template name.
7910 /// \param PrimaryTemplate the template parameters of the primary class
7912 /// \param NumExplicit the number of explicitly-specified template arguments.
7913 /// \param TemplateArgs the template arguments of the class template
7914 /// partial specialization.
7916 /// \returns \c true if there was an error, \c false otherwise.
7917 bool Sema::CheckTemplatePartialSpecializationArgs(
7918 SourceLocation TemplateNameLoc, TemplateDecl *PrimaryTemplate,
7919 unsigned NumExplicit, ArrayRef<TemplateArgument> TemplateArgs) {
7920 // We have to be conservative when checking a template in a dependent
7922 if (PrimaryTemplate->getDeclContext()->isDependentContext())
7925 TemplateParameterList *TemplateParams =
7926 PrimaryTemplate->getTemplateParameters();
7927 for (unsigned I = 0, N = TemplateParams->size(); I != N; ++I) {
7928 NonTypeTemplateParmDecl *Param
7929 = dyn_cast<NonTypeTemplateParmDecl>(TemplateParams->getParam(I));
7933 if (CheckNonTypeTemplatePartialSpecializationArgs(*this, TemplateNameLoc,
7934 Param, &TemplateArgs[I],
7935 1, I >= NumExplicit))
7942 DeclResult Sema::ActOnClassTemplateSpecialization(
7943 Scope *S, unsigned TagSpec, TagUseKind TUK, SourceLocation KWLoc,
7944 SourceLocation ModulePrivateLoc, CXXScopeSpec &SS,
7945 TemplateIdAnnotation &TemplateId, const ParsedAttributesView &Attr,
7946 MultiTemplateParamsArg TemplateParameterLists, SkipBodyInfo *SkipBody) {
7947 assert(TUK != TUK_Reference && "References are not specializations");
7949 // NOTE: KWLoc is the location of the tag keyword. This will instead
7950 // store the location of the outermost template keyword in the declaration.
7951 SourceLocation TemplateKWLoc = TemplateParameterLists.size() > 0
7952 ? TemplateParameterLists[0]->getTemplateLoc() : KWLoc;
7953 SourceLocation TemplateNameLoc = TemplateId.TemplateNameLoc;
7954 SourceLocation LAngleLoc = TemplateId.LAngleLoc;
7955 SourceLocation RAngleLoc = TemplateId.RAngleLoc;
7957 // Find the class template we're specializing
7958 TemplateName Name = TemplateId.Template.get();
7959 ClassTemplateDecl *ClassTemplate
7960 = dyn_cast_or_null<ClassTemplateDecl>(Name.getAsTemplateDecl());
7962 if (!ClassTemplate) {
7963 Diag(TemplateNameLoc, diag::err_not_class_template_specialization)
7964 << (Name.getAsTemplateDecl() &&
7965 isa<TemplateTemplateParmDecl>(Name.getAsTemplateDecl()));
7969 bool isMemberSpecialization = false;
7970 bool isPartialSpecialization = false;
7972 // Check the validity of the template headers that introduce this
7974 // FIXME: We probably shouldn't complain about these headers for
7975 // friend declarations.
7976 bool Invalid = false;
7977 TemplateParameterList *TemplateParams =
7978 MatchTemplateParametersToScopeSpecifier(
7979 KWLoc, TemplateNameLoc, SS, &TemplateId,
7980 TemplateParameterLists, TUK == TUK_Friend, isMemberSpecialization,
7985 if (TemplateParams && TemplateParams->size() > 0) {
7986 isPartialSpecialization = true;
7988 if (TUK == TUK_Friend) {
7989 Diag(KWLoc, diag::err_partial_specialization_friend)
7990 << SourceRange(LAngleLoc, RAngleLoc);
7994 // C++ [temp.class.spec]p10:
7995 // The template parameter list of a specialization shall not
7996 // contain default template argument values.
7997 for (unsigned I = 0, N = TemplateParams->size(); I != N; ++I) {
7998 Decl *Param = TemplateParams->getParam(I);
7999 if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(Param)) {
8000 if (TTP->hasDefaultArgument()) {
8001 Diag(TTP->getDefaultArgumentLoc(),
8002 diag::err_default_arg_in_partial_spec);
8003 TTP->removeDefaultArgument();
8005 } else if (NonTypeTemplateParmDecl *NTTP
8006 = dyn_cast<NonTypeTemplateParmDecl>(Param)) {
8007 if (Expr *DefArg = NTTP->getDefaultArgument()) {
8008 Diag(NTTP->getDefaultArgumentLoc(),
8009 diag::err_default_arg_in_partial_spec)
8010 << DefArg->getSourceRange();
8011 NTTP->removeDefaultArgument();
8014 TemplateTemplateParmDecl *TTP = cast<TemplateTemplateParmDecl>(Param);
8015 if (TTP->hasDefaultArgument()) {
8016 Diag(TTP->getDefaultArgument().getLocation(),
8017 diag::err_default_arg_in_partial_spec)
8018 << TTP->getDefaultArgument().getSourceRange();
8019 TTP->removeDefaultArgument();
8023 } else if (TemplateParams) {
8024 if (TUK == TUK_Friend)
8025 Diag(KWLoc, diag::err_template_spec_friend)
8026 << FixItHint::CreateRemoval(
8027 SourceRange(TemplateParams->getTemplateLoc(),
8028 TemplateParams->getRAngleLoc()))
8029 << SourceRange(LAngleLoc, RAngleLoc);
8031 assert(TUK == TUK_Friend && "should have a 'template<>' for this decl");
8034 // Check that the specialization uses the same tag kind as the
8035 // original template.
8036 TagTypeKind Kind = TypeWithKeyword::getTagTypeKindForTypeSpec(TagSpec);
8037 assert(Kind != TTK_Enum && "Invalid enum tag in class template spec!");
8038 if (!isAcceptableTagRedeclaration(ClassTemplate->getTemplatedDecl(),
8039 Kind, TUK == TUK_Definition, KWLoc,
8040 ClassTemplate->getIdentifier())) {
8041 Diag(KWLoc, diag::err_use_with_wrong_tag)
8043 << FixItHint::CreateReplacement(KWLoc,
8044 ClassTemplate->getTemplatedDecl()->getKindName());
8045 Diag(ClassTemplate->getTemplatedDecl()->getLocation(),
8046 diag::note_previous_use);
8047 Kind = ClassTemplate->getTemplatedDecl()->getTagKind();
8050 // Translate the parser's template argument list in our AST format.
8051 TemplateArgumentListInfo TemplateArgs =
8052 makeTemplateArgumentListInfo(*this, TemplateId);
8054 // Check for unexpanded parameter packs in any of the template arguments.
8055 for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I)
8056 if (DiagnoseUnexpandedParameterPack(TemplateArgs[I],
8057 UPPC_PartialSpecialization))
8060 // Check that the template argument list is well-formed for this
8062 SmallVector<TemplateArgument, 4> Converted;
8063 if (CheckTemplateArgumentList(ClassTemplate, TemplateNameLoc,
8064 TemplateArgs, false, Converted,
8065 /*UpdateArgsWithConversion=*/true))
8068 // Find the class template (partial) specialization declaration that
8069 // corresponds to these arguments.
8070 if (isPartialSpecialization) {
8071 if (CheckTemplatePartialSpecializationArgs(TemplateNameLoc, ClassTemplate,
8072 TemplateArgs.size(), Converted))
8075 // FIXME: Move this to CheckTemplatePartialSpecializationArgs so we
8076 // also do it during instantiation.
8077 bool InstantiationDependent;
8078 if (!Name.isDependent() &&
8079 !TemplateSpecializationType::anyDependentTemplateArguments(
8080 TemplateArgs.arguments(), InstantiationDependent)) {
8081 Diag(TemplateNameLoc, diag::err_partial_spec_fully_specialized)
8082 << ClassTemplate->getDeclName();
8083 isPartialSpecialization = false;
8087 void *InsertPos = nullptr;
8088 ClassTemplateSpecializationDecl *PrevDecl = nullptr;
8090 if (isPartialSpecialization)
8091 PrevDecl = ClassTemplate->findPartialSpecialization(Converted,
8095 PrevDecl = ClassTemplate->findSpecialization(Converted, InsertPos);
8097 ClassTemplateSpecializationDecl *Specialization = nullptr;
8099 // Check whether we can declare a class template specialization in
8100 // the current scope.
8101 if (TUK != TUK_Friend &&
8102 CheckTemplateSpecializationScope(*this, ClassTemplate, PrevDecl,
8104 isPartialSpecialization))
8107 // The canonical type
8109 if (isPartialSpecialization) {
8110 // Build the canonical type that describes the converted template
8111 // arguments of the class template partial specialization.
8112 TemplateName CanonTemplate = Context.getCanonicalTemplateName(Name);
8113 CanonType = Context.getTemplateSpecializationType(CanonTemplate,
8116 if (Context.hasSameType(CanonType,
8117 ClassTemplate->getInjectedClassNameSpecialization()) &&
8118 (!Context.getLangOpts().CPlusPlus2a ||
8119 !TemplateParams->hasAssociatedConstraints())) {
8120 // C++ [temp.class.spec]p9b3:
8122 // -- The argument list of the specialization shall not be identical
8123 // to the implicit argument list of the primary template.
8125 // This rule has since been removed, because it's redundant given DR1495,
8126 // but we keep it because it produces better diagnostics and recovery.
8127 Diag(TemplateNameLoc, diag::err_partial_spec_args_match_primary_template)
8128 << /*class template*/0 << (TUK == TUK_Definition)
8129 << FixItHint::CreateRemoval(SourceRange(LAngleLoc, RAngleLoc));
8130 return CheckClassTemplate(S, TagSpec, TUK, KWLoc, SS,
8131 ClassTemplate->getIdentifier(),
8135 AS_none, /*ModulePrivateLoc=*/SourceLocation(),
8136 /*FriendLoc*/SourceLocation(),
8137 TemplateParameterLists.size() - 1,
8138 TemplateParameterLists.data());
8141 // Create a new class template partial specialization declaration node.
8142 ClassTemplatePartialSpecializationDecl *PrevPartial
8143 = cast_or_null<ClassTemplatePartialSpecializationDecl>(PrevDecl);
8144 ClassTemplatePartialSpecializationDecl *Partial
8145 = ClassTemplatePartialSpecializationDecl::Create(Context, Kind,
8146 ClassTemplate->getDeclContext(),
8147 KWLoc, TemplateNameLoc,
8154 SetNestedNameSpecifier(*this, Partial, SS);
8155 if (TemplateParameterLists.size() > 1 && SS.isSet()) {
8156 Partial->setTemplateParameterListsInfo(
8157 Context, TemplateParameterLists.drop_back(1));
8161 ClassTemplate->AddPartialSpecialization(Partial, InsertPos);
8162 Specialization = Partial;
8164 // If we are providing an explicit specialization of a member class
8165 // template specialization, make a note of that.
8166 if (PrevPartial && PrevPartial->getInstantiatedFromMember())
8167 PrevPartial->setMemberSpecialization();
8169 CheckTemplatePartialSpecialization(Partial);
8171 // Create a new class template specialization declaration node for
8172 // this explicit specialization or friend declaration.
8174 = ClassTemplateSpecializationDecl::Create(Context, Kind,
8175 ClassTemplate->getDeclContext(),
8176 KWLoc, TemplateNameLoc,
8180 SetNestedNameSpecifier(*this, Specialization, SS);
8181 if (TemplateParameterLists.size() > 0) {
8182 Specialization->setTemplateParameterListsInfo(Context,
8183 TemplateParameterLists);
8187 ClassTemplate->AddSpecialization(Specialization, InsertPos);
8189 if (CurContext->isDependentContext()) {
8190 TemplateName CanonTemplate = Context.getCanonicalTemplateName(Name);
8191 CanonType = Context.getTemplateSpecializationType(
8192 CanonTemplate, Converted);
8194 CanonType = Context.getTypeDeclType(Specialization);
8198 // C++ [temp.expl.spec]p6:
8199 // If a template, a member template or the member of a class template is
8200 // explicitly specialized then that specialization shall be declared
8201 // before the first use of that specialization that would cause an implicit
8202 // instantiation to take place, in every translation unit in which such a
8203 // use occurs; no diagnostic is required.
8204 if (PrevDecl && PrevDecl->getPointOfInstantiation().isValid()) {
8206 for (Decl *Prev = PrevDecl; Prev; Prev = Prev->getPreviousDecl()) {
8207 // Is there any previous explicit specialization declaration?
8208 if (getTemplateSpecializationKind(Prev) == TSK_ExplicitSpecialization) {
8215 SourceRange Range(TemplateNameLoc, RAngleLoc);
8216 Diag(TemplateNameLoc, diag::err_specialization_after_instantiation)
8217 << Context.getTypeDeclType(Specialization) << Range;
8219 Diag(PrevDecl->getPointOfInstantiation(),
8220 diag::note_instantiation_required_here)
8221 << (PrevDecl->getTemplateSpecializationKind()
8222 != TSK_ImplicitInstantiation);
8227 // If this is not a friend, note that this is an explicit specialization.
8228 if (TUK != TUK_Friend)
8229 Specialization->setSpecializationKind(TSK_ExplicitSpecialization);
8231 // Check that this isn't a redefinition of this specialization.
8232 if (TUK == TUK_Definition) {
8233 RecordDecl *Def = Specialization->getDefinition();
8234 NamedDecl *Hidden = nullptr;
8235 if (Def && SkipBody && !hasVisibleDefinition(Def, &Hidden)) {
8236 SkipBody->ShouldSkip = true;
8237 SkipBody->Previous = Def;
8238 makeMergedDefinitionVisible(Hidden);
8240 SourceRange Range(TemplateNameLoc, RAngleLoc);
8241 Diag(TemplateNameLoc, diag::err_redefinition) << Specialization << Range;
8242 Diag(Def->getLocation(), diag::note_previous_definition);
8243 Specialization->setInvalidDecl();
8248 ProcessDeclAttributeList(S, Specialization, Attr);
8250 // Add alignment attributes if necessary; these attributes are checked when
8251 // the ASTContext lays out the structure.
8252 if (TUK == TUK_Definition && (!SkipBody || !SkipBody->ShouldSkip)) {
8253 AddAlignmentAttributesForRecord(Specialization);
8254 AddMsStructLayoutForRecord(Specialization);
8257 if (ModulePrivateLoc.isValid())
8258 Diag(Specialization->getLocation(), diag::err_module_private_specialization)
8259 << (isPartialSpecialization? 1 : 0)
8260 << FixItHint::CreateRemoval(ModulePrivateLoc);
8262 // Build the fully-sugared type for this class template
8263 // specialization as the user wrote in the specialization
8264 // itself. This means that we'll pretty-print the type retrieved
8265 // from the specialization's declaration the way that the user
8266 // actually wrote the specialization, rather than formatting the
8267 // name based on the "canonical" representation used to store the
8268 // template arguments in the specialization.
8269 TypeSourceInfo *WrittenTy
8270 = Context.getTemplateSpecializationTypeInfo(Name, TemplateNameLoc,
8271 TemplateArgs, CanonType);
8272 if (TUK != TUK_Friend) {
8273 Specialization->setTypeAsWritten(WrittenTy);
8274 Specialization->setTemplateKeywordLoc(TemplateKWLoc);
8277 // C++ [temp.expl.spec]p9:
8278 // A template explicit specialization is in the scope of the
8279 // namespace in which the template was defined.
8281 // We actually implement this paragraph where we set the semantic
8282 // context (in the creation of the ClassTemplateSpecializationDecl),
8283 // but we also maintain the lexical context where the actual
8284 // definition occurs.
8285 Specialization->setLexicalDeclContext(CurContext);
8287 // We may be starting the definition of this specialization.
8288 if (TUK == TUK_Definition && (!SkipBody || !SkipBody->ShouldSkip))
8289 Specialization->startDefinition();
8291 if (TUK == TUK_Friend) {
8292 FriendDecl *Friend = FriendDecl::Create(Context, CurContext,
8296 Friend->setAccess(AS_public);
8297 CurContext->addDecl(Friend);
8299 // Add the specialization into its lexical context, so that it can
8300 // be seen when iterating through the list of declarations in that
8301 // context. However, specializations are not found by name lookup.
8302 CurContext->addDecl(Specialization);
8305 if (SkipBody && SkipBody->ShouldSkip)
8306 return SkipBody->Previous;
8308 return Specialization;
8311 Decl *Sema::ActOnTemplateDeclarator(Scope *S,
8312 MultiTemplateParamsArg TemplateParameterLists,
8314 Decl *NewDecl = HandleDeclarator(S, D, TemplateParameterLists);
8315 ActOnDocumentableDecl(NewDecl);
8319 Decl *Sema::ActOnConceptDefinition(Scope *S,
8320 MultiTemplateParamsArg TemplateParameterLists,
8321 IdentifierInfo *Name, SourceLocation NameLoc,
8322 Expr *ConstraintExpr) {
8323 DeclContext *DC = CurContext;
8325 if (!DC->getRedeclContext()->isFileContext()) {
8327 diag::err_concept_decls_may_only_appear_in_global_namespace_scope);
8331 if (TemplateParameterLists.size() > 1) {
8332 Diag(NameLoc, diag::err_concept_extra_headers);
8336 if (TemplateParameterLists.front()->size() == 0) {
8337 Diag(NameLoc, diag::err_concept_no_parameters);
8341 ConceptDecl *NewDecl = ConceptDecl::Create(Context, DC, NameLoc, Name,
8342 TemplateParameterLists.front(),
8345 if (NewDecl->hasAssociatedConstraints()) {
8346 // C++2a [temp.concept]p4:
8347 // A concept shall not have associated constraints.
8348 Diag(NameLoc, diag::err_concept_no_associated_constraints);
8349 NewDecl->setInvalidDecl();
8352 // Check for conflicting previous declaration.
8353 DeclarationNameInfo NameInfo(NewDecl->getDeclName(), NameLoc);
8354 LookupResult Previous(*this, NameInfo, LookupOrdinaryName,
8355 ForVisibleRedeclaration);
8356 LookupName(Previous, S);
8358 FilterLookupForScope(Previous, DC, S, /*ConsiderLinkage=*/false,
8359 /*AllowInlineNamespace*/false);
8360 if (!Previous.empty()) {
8361 auto *Old = Previous.getRepresentativeDecl();
8362 Diag(NameLoc, isa<ConceptDecl>(Old) ? diag::err_redefinition :
8363 diag::err_redefinition_different_kind) << NewDecl->getDeclName();
8364 Diag(Old->getLocation(), diag::note_previous_definition);
8367 ActOnDocumentableDecl(NewDecl);
8368 PushOnScopeChains(NewDecl, S);
8372 /// \brief Strips various properties off an implicit instantiation
8373 /// that has just been explicitly specialized.
8374 static void StripImplicitInstantiation(NamedDecl *D) {
8375 D->dropAttr<DLLImportAttr>();
8376 D->dropAttr<DLLExportAttr>();
8378 if (FunctionDecl *FD = dyn_cast<FunctionDecl>(D))
8379 FD->setInlineSpecified(false);
8382 /// Compute the diagnostic location for an explicit instantiation
8383 // declaration or definition.
8384 static SourceLocation DiagLocForExplicitInstantiation(
8385 NamedDecl* D, SourceLocation PointOfInstantiation) {
8386 // Explicit instantiations following a specialization have no effect and
8387 // hence no PointOfInstantiation. In that case, walk decl backwards
8388 // until a valid name loc is found.
8389 SourceLocation PrevDiagLoc = PointOfInstantiation;
8390 for (Decl *Prev = D; Prev && !PrevDiagLoc.isValid();
8391 Prev = Prev->getPreviousDecl()) {
8392 PrevDiagLoc = Prev->getLocation();
8394 assert(PrevDiagLoc.isValid() &&
8395 "Explicit instantiation without point of instantiation?");
8399 /// Diagnose cases where we have an explicit template specialization
8400 /// before/after an explicit template instantiation, producing diagnostics
8401 /// for those cases where they are required and determining whether the
8402 /// new specialization/instantiation will have any effect.
8404 /// \param NewLoc the location of the new explicit specialization or
8407 /// \param NewTSK the kind of the new explicit specialization or instantiation.
8409 /// \param PrevDecl the previous declaration of the entity.
8411 /// \param PrevTSK the kind of the old explicit specialization or instantiatin.
8413 /// \param PrevPointOfInstantiation if valid, indicates where the previus
8414 /// declaration was instantiated (either implicitly or explicitly).
8416 /// \param HasNoEffect will be set to true to indicate that the new
8417 /// specialization or instantiation has no effect and should be ignored.
8419 /// \returns true if there was an error that should prevent the introduction of
8420 /// the new declaration into the AST, false otherwise.
8422 Sema::CheckSpecializationInstantiationRedecl(SourceLocation NewLoc,
8423 TemplateSpecializationKind NewTSK,
8424 NamedDecl *PrevDecl,
8425 TemplateSpecializationKind PrevTSK,
8426 SourceLocation PrevPointOfInstantiation,
8427 bool &HasNoEffect) {
8428 HasNoEffect = false;
8431 case TSK_Undeclared:
8432 case TSK_ImplicitInstantiation:
8434 (PrevTSK == TSK_Undeclared || PrevTSK == TSK_ImplicitInstantiation) &&
8435 "previous declaration must be implicit!");
8438 case TSK_ExplicitSpecialization:
8440 case TSK_Undeclared:
8441 case TSK_ExplicitSpecialization:
8442 // Okay, we're just specializing something that is either already
8443 // explicitly specialized or has merely been mentioned without any
8447 case TSK_ImplicitInstantiation:
8448 if (PrevPointOfInstantiation.isInvalid()) {
8449 // The declaration itself has not actually been instantiated, so it is
8450 // still okay to specialize it.
8451 StripImplicitInstantiation(PrevDecl);
8457 case TSK_ExplicitInstantiationDeclaration:
8458 case TSK_ExplicitInstantiationDefinition:
8459 assert((PrevTSK == TSK_ImplicitInstantiation ||
8460 PrevPointOfInstantiation.isValid()) &&
8461 "Explicit instantiation without point of instantiation?");
8463 // C++ [temp.expl.spec]p6:
8464 // If a template, a member template or the member of a class template
8465 // is explicitly specialized then that specialization shall be declared
8466 // before the first use of that specialization that would cause an
8467 // implicit instantiation to take place, in every translation unit in
8468 // which such a use occurs; no diagnostic is required.
8469 for (Decl *Prev = PrevDecl; Prev; Prev = Prev->getPreviousDecl()) {
8470 // Is there any previous explicit specialization declaration?
8471 if (getTemplateSpecializationKind(Prev) == TSK_ExplicitSpecialization)
8475 Diag(NewLoc, diag::err_specialization_after_instantiation)
8477 Diag(PrevPointOfInstantiation, diag::note_instantiation_required_here)
8478 << (PrevTSK != TSK_ImplicitInstantiation);
8482 llvm_unreachable("The switch over PrevTSK must be exhaustive.");
8484 case TSK_ExplicitInstantiationDeclaration:
8486 case TSK_ExplicitInstantiationDeclaration:
8487 // This explicit instantiation declaration is redundant (that's okay).
8491 case TSK_Undeclared:
8492 case TSK_ImplicitInstantiation:
8493 // We're explicitly instantiating something that may have already been
8494 // implicitly instantiated; that's fine.
8497 case TSK_ExplicitSpecialization:
8498 // C++0x [temp.explicit]p4:
8499 // For a given set of template parameters, if an explicit instantiation
8500 // of a template appears after a declaration of an explicit
8501 // specialization for that template, the explicit instantiation has no
8506 case TSK_ExplicitInstantiationDefinition:
8507 // C++0x [temp.explicit]p10:
8508 // If an entity is the subject of both an explicit instantiation
8509 // declaration and an explicit instantiation definition in the same
8510 // translation unit, the definition shall follow the declaration.
8512 diag::err_explicit_instantiation_declaration_after_definition);
8514 // Explicit instantiations following a specialization have no effect and
8515 // hence no PrevPointOfInstantiation. In that case, walk decl backwards
8516 // until a valid name loc is found.
8517 Diag(DiagLocForExplicitInstantiation(PrevDecl, PrevPointOfInstantiation),
8518 diag::note_explicit_instantiation_definition_here);
8522 llvm_unreachable("Unexpected TemplateSpecializationKind!");
8524 case TSK_ExplicitInstantiationDefinition:
8526 case TSK_Undeclared:
8527 case TSK_ImplicitInstantiation:
8528 // We're explicitly instantiating something that may have already been
8529 // implicitly instantiated; that's fine.
8532 case TSK_ExplicitSpecialization:
8533 // C++ DR 259, C++0x [temp.explicit]p4:
8534 // For a given set of template parameters, if an explicit
8535 // instantiation of a template appears after a declaration of
8536 // an explicit specialization for that template, the explicit
8537 // instantiation has no effect.
8538 Diag(NewLoc, diag::warn_explicit_instantiation_after_specialization)
8540 Diag(PrevDecl->getLocation(),
8541 diag::note_previous_template_specialization);
8545 case TSK_ExplicitInstantiationDeclaration:
8546 // We're explicitly instantiating a definition for something for which we
8547 // were previously asked to suppress instantiations. That's fine.
8549 // C++0x [temp.explicit]p4:
8550 // For a given set of template parameters, if an explicit instantiation
8551 // of a template appears after a declaration of an explicit
8552 // specialization for that template, the explicit instantiation has no
8554 for (Decl *Prev = PrevDecl; Prev; Prev = Prev->getPreviousDecl()) {
8555 // Is there any previous explicit specialization declaration?
8556 if (getTemplateSpecializationKind(Prev) == TSK_ExplicitSpecialization) {
8564 case TSK_ExplicitInstantiationDefinition:
8565 // C++0x [temp.spec]p5:
8566 // For a given template and a given set of template-arguments,
8567 // - an explicit instantiation definition shall appear at most once
8570 // MSVCCompat: MSVC silently ignores duplicate explicit instantiations.
8571 Diag(NewLoc, (getLangOpts().MSVCCompat)
8572 ? diag::ext_explicit_instantiation_duplicate
8573 : diag::err_explicit_instantiation_duplicate)
8575 Diag(DiagLocForExplicitInstantiation(PrevDecl, PrevPointOfInstantiation),
8576 diag::note_previous_explicit_instantiation);
8582 llvm_unreachable("Missing specialization/instantiation case?");
8585 /// Perform semantic analysis for the given dependent function
8586 /// template specialization.
8588 /// The only possible way to get a dependent function template specialization
8589 /// is with a friend declaration, like so:
8592 /// template \<class T> void foo(T);
8593 /// template \<class T> class A {
8594 /// friend void foo<>(T);
8598 /// There really isn't any useful analysis we can do here, so we
8599 /// just store the information.
8601 Sema::CheckDependentFunctionTemplateSpecialization(FunctionDecl *FD,
8602 const TemplateArgumentListInfo &ExplicitTemplateArgs,
8603 LookupResult &Previous) {
8604 // Remove anything from Previous that isn't a function template in
8605 // the correct context.
8606 DeclContext *FDLookupContext = FD->getDeclContext()->getRedeclContext();
8607 LookupResult::Filter F = Previous.makeFilter();
8608 enum DiscardReason { NotAFunctionTemplate, NotAMemberOfEnclosing };
8609 SmallVector<std::pair<DiscardReason, Decl *>, 8> DiscardedCandidates;
8610 while (F.hasNext()) {
8611 NamedDecl *D = F.next()->getUnderlyingDecl();
8612 if (!isa<FunctionTemplateDecl>(D)) {
8614 DiscardedCandidates.push_back(std::make_pair(NotAFunctionTemplate, D));
8618 if (!FDLookupContext->InEnclosingNamespaceSetOf(
8619 D->getDeclContext()->getRedeclContext())) {
8621 DiscardedCandidates.push_back(std::make_pair(NotAMemberOfEnclosing, D));
8627 if (Previous.empty()) {
8628 Diag(FD->getLocation(),
8629 diag::err_dependent_function_template_spec_no_match);
8630 for (auto &P : DiscardedCandidates)
8631 Diag(P.second->getLocation(),
8632 diag::note_dependent_function_template_spec_discard_reason)
8637 FD->setDependentTemplateSpecialization(Context, Previous.asUnresolvedSet(),
8638 ExplicitTemplateArgs);
8642 /// Perform semantic analysis for the given function template
8645 /// This routine performs all of the semantic analysis required for an
8646 /// explicit function template specialization. On successful completion,
8647 /// the function declaration \p FD will become a function template
8650 /// \param FD the function declaration, which will be updated to become a
8651 /// function template specialization.
8653 /// \param ExplicitTemplateArgs the explicitly-provided template arguments,
8654 /// if any. Note that this may be valid info even when 0 arguments are
8655 /// explicitly provided as in, e.g., \c void sort<>(char*, char*);
8656 /// as it anyway contains info on the angle brackets locations.
8658 /// \param Previous the set of declarations that may be specialized by
8659 /// this function specialization.
8661 /// \param QualifiedFriend whether this is a lookup for a qualified friend
8662 /// declaration with no explicit template argument list that might be
8663 /// befriending a function template specialization.
8664 bool Sema::CheckFunctionTemplateSpecialization(
8665 FunctionDecl *FD, TemplateArgumentListInfo *ExplicitTemplateArgs,
8666 LookupResult &Previous, bool QualifiedFriend) {
8667 // The set of function template specializations that could match this
8668 // explicit function template specialization.
8669 UnresolvedSet<8> Candidates;
8670 TemplateSpecCandidateSet FailedCandidates(FD->getLocation(),
8671 /*ForTakingAddress=*/false);
8673 llvm::SmallDenseMap<FunctionDecl *, TemplateArgumentListInfo, 8>
8674 ConvertedTemplateArgs;
8676 DeclContext *FDLookupContext = FD->getDeclContext()->getRedeclContext();
8677 for (LookupResult::iterator I = Previous.begin(), E = Previous.end();
8679 NamedDecl *Ovl = (*I)->getUnderlyingDecl();
8680 if (FunctionTemplateDecl *FunTmpl = dyn_cast<FunctionTemplateDecl>(Ovl)) {
8681 // Only consider templates found within the same semantic lookup scope as
8683 if (!FDLookupContext->InEnclosingNamespaceSetOf(
8684 Ovl->getDeclContext()->getRedeclContext()))
8687 // When matching a constexpr member function template specialization
8688 // against the primary template, we don't yet know whether the
8689 // specialization has an implicit 'const' (because we don't know whether
8690 // it will be a static member function until we know which template it
8691 // specializes), so adjust it now assuming it specializes this template.
8692 QualType FT = FD->getType();
8693 if (FD->isConstexpr()) {
8694 CXXMethodDecl *OldMD =
8695 dyn_cast<CXXMethodDecl>(FunTmpl->getTemplatedDecl());
8696 if (OldMD && OldMD->isConst()) {
8697 const FunctionProtoType *FPT = FT->castAs<FunctionProtoType>();
8698 FunctionProtoType::ExtProtoInfo EPI = FPT->getExtProtoInfo();
8699 EPI.TypeQuals.addConst();
8700 FT = Context.getFunctionType(FPT->getReturnType(),
8701 FPT->getParamTypes(), EPI);
8705 TemplateArgumentListInfo Args;
8706 if (ExplicitTemplateArgs)
8707 Args = *ExplicitTemplateArgs;
8709 // C++ [temp.expl.spec]p11:
8710 // A trailing template-argument can be left unspecified in the
8711 // template-id naming an explicit function template specialization
8712 // provided it can be deduced from the function argument type.
8713 // Perform template argument deduction to determine whether we may be
8714 // specializing this template.
8715 // FIXME: It is somewhat wasteful to build
8716 TemplateDeductionInfo Info(FailedCandidates.getLocation());
8717 FunctionDecl *Specialization = nullptr;
8718 if (TemplateDeductionResult TDK = DeduceTemplateArguments(
8719 cast<FunctionTemplateDecl>(FunTmpl->getFirstDecl()),
8720 ExplicitTemplateArgs ? &Args : nullptr, FT, Specialization,
8722 // Template argument deduction failed; record why it failed, so
8723 // that we can provide nifty diagnostics.
8724 FailedCandidates.addCandidate().set(
8725 I.getPair(), FunTmpl->getTemplatedDecl(),
8726 MakeDeductionFailureInfo(Context, TDK, Info));
8731 // Target attributes are part of the cuda function signature, so
8732 // the deduced template's cuda target must match that of the
8733 // specialization. Given that C++ template deduction does not
8734 // take target attributes into account, we reject candidates
8735 // here that have a different target.
8736 if (LangOpts.CUDA &&
8737 IdentifyCUDATarget(Specialization,
8738 /* IgnoreImplicitHDAttr = */ true) !=
8739 IdentifyCUDATarget(FD, /* IgnoreImplicitHDAttr = */ true)) {
8740 FailedCandidates.addCandidate().set(
8741 I.getPair(), FunTmpl->getTemplatedDecl(),
8742 MakeDeductionFailureInfo(Context, TDK_CUDATargetMismatch, Info));
8746 // Record this candidate.
8747 if (ExplicitTemplateArgs)
8748 ConvertedTemplateArgs[Specialization] = std::move(Args);
8749 Candidates.addDecl(Specialization, I.getAccess());
8753 // For a qualified friend declaration (with no explicit marker to indicate
8754 // that a template specialization was intended), note all (template and
8755 // non-template) candidates.
8756 if (QualifiedFriend && Candidates.empty()) {
8757 Diag(FD->getLocation(), diag::err_qualified_friend_no_match)
8758 << FD->getDeclName() << FDLookupContext;
8759 // FIXME: We should form a single candidate list and diagnose all
8760 // candidates at once, to get proper sorting and limiting.
8761 for (auto *OldND : Previous) {
8762 if (auto *OldFD = dyn_cast<FunctionDecl>(OldND->getUnderlyingDecl()))
8763 NoteOverloadCandidate(OldND, OldFD, CRK_None, FD->getType(), false);
8765 FailedCandidates.NoteCandidates(*this, FD->getLocation());
8769 // Find the most specialized function template.
8770 UnresolvedSetIterator Result = getMostSpecialized(
8771 Candidates.begin(), Candidates.end(), FailedCandidates, FD->getLocation(),
8772 PDiag(diag::err_function_template_spec_no_match) << FD->getDeclName(),
8773 PDiag(diag::err_function_template_spec_ambiguous)
8774 << FD->getDeclName() << (ExplicitTemplateArgs != nullptr),
8775 PDiag(diag::note_function_template_spec_matched));
8777 if (Result == Candidates.end())
8780 // Ignore access information; it doesn't figure into redeclaration checking.
8781 FunctionDecl *Specialization = cast<FunctionDecl>(*Result);
8783 FunctionTemplateSpecializationInfo *SpecInfo
8784 = Specialization->getTemplateSpecializationInfo();
8785 assert(SpecInfo && "Function template specialization info missing?");
8787 // Note: do not overwrite location info if previous template
8788 // specialization kind was explicit.
8789 TemplateSpecializationKind TSK = SpecInfo->getTemplateSpecializationKind();
8790 if (TSK == TSK_Undeclared || TSK == TSK_ImplicitInstantiation) {
8791 Specialization->setLocation(FD->getLocation());
8792 Specialization->setLexicalDeclContext(FD->getLexicalDeclContext());
8793 // C++11 [dcl.constexpr]p1: An explicit specialization of a constexpr
8794 // function can differ from the template declaration with respect to
8795 // the constexpr specifier.
8796 // FIXME: We need an update record for this AST mutation.
8797 // FIXME: What if there are multiple such prior declarations (for instance,
8798 // from different modules)?
8799 Specialization->setConstexprKind(FD->getConstexprKind());
8802 // FIXME: Check if the prior specialization has a point of instantiation.
8803 // If so, we have run afoul of .
8805 // If this is a friend declaration, then we're not really declaring
8806 // an explicit specialization.
8807 bool isFriend = (FD->getFriendObjectKind() != Decl::FOK_None);
8809 // Check the scope of this explicit specialization.
8811 CheckTemplateSpecializationScope(*this,
8812 Specialization->getPrimaryTemplate(),
8813 Specialization, FD->getLocation(),
8817 // C++ [temp.expl.spec]p6:
8818 // If a template, a member template or the member of a class template is
8819 // explicitly specialized then that specialization shall be declared
8820 // before the first use of that specialization that would cause an implicit
8821 // instantiation to take place, in every translation unit in which such a
8822 // use occurs; no diagnostic is required.
8823 bool HasNoEffect = false;
8825 CheckSpecializationInstantiationRedecl(FD->getLocation(),
8826 TSK_ExplicitSpecialization,
8828 SpecInfo->getTemplateSpecializationKind(),
8829 SpecInfo->getPointOfInstantiation(),
8833 // Mark the prior declaration as an explicit specialization, so that later
8834 // clients know that this is an explicit specialization.
8836 // Since explicit specializations do not inherit '=delete' from their
8837 // primary function template - check if the 'specialization' that was
8838 // implicitly generated (during template argument deduction for partial
8839 // ordering) from the most specialized of all the function templates that
8840 // 'FD' could have been specializing, has a 'deleted' definition. If so,
8841 // first check that it was implicitly generated during template argument
8842 // deduction by making sure it wasn't referenced, and then reset the deleted
8843 // flag to not-deleted, so that we can inherit that information from 'FD'.
8844 if (Specialization->isDeleted() && !SpecInfo->isExplicitSpecialization() &&
8845 !Specialization->getCanonicalDecl()->isReferenced()) {
8846 // FIXME: This assert will not hold in the presence of modules.
8848 Specialization->getCanonicalDecl() == Specialization &&
8849 "This must be the only existing declaration of this specialization");
8850 // FIXME: We need an update record for this AST mutation.
8851 Specialization->setDeletedAsWritten(false);
8853 // FIXME: We need an update record for this AST mutation.
8854 SpecInfo->setTemplateSpecializationKind(TSK_ExplicitSpecialization);
8855 MarkUnusedFileScopedDecl(Specialization);
8858 // Turn the given function declaration into a function template
8859 // specialization, with the template arguments from the previous
8861 // Take copies of (semantic and syntactic) template argument lists.
8862 const TemplateArgumentList* TemplArgs = new (Context)
8863 TemplateArgumentList(Specialization->getTemplateSpecializationArgs());
8864 FD->setFunctionTemplateSpecialization(
8865 Specialization->getPrimaryTemplate(), TemplArgs, /*InsertPos=*/nullptr,
8866 SpecInfo->getTemplateSpecializationKind(),
8867 ExplicitTemplateArgs ? &ConvertedTemplateArgs[Specialization] : nullptr);
8869 // A function template specialization inherits the target attributes
8870 // of its template. (We require the attributes explicitly in the
8871 // code to match, but a template may have implicit attributes by
8872 // virtue e.g. of being constexpr, and it passes these implicit
8873 // attributes on to its specializations.)
8875 inheritCUDATargetAttrs(FD, *Specialization->getPrimaryTemplate());
8877 // The "previous declaration" for this function template specialization is
8878 // the prior function template specialization.
8880 Previous.addDecl(Specialization);
8884 /// Perform semantic analysis for the given non-template member
8887 /// This routine performs all of the semantic analysis required for an
8888 /// explicit member function specialization. On successful completion,
8889 /// the function declaration \p FD will become a member function
8892 /// \param Member the member declaration, which will be updated to become a
8895 /// \param Previous the set of declarations, one of which may be specialized
8896 /// by this function specialization; the set will be modified to contain the
8897 /// redeclared member.
8899 Sema::CheckMemberSpecialization(NamedDecl *Member, LookupResult &Previous) {
8900 assert(!isa<TemplateDecl>(Member) && "Only for non-template members");
8902 // Try to find the member we are instantiating.
8903 NamedDecl *FoundInstantiation = nullptr;
8904 NamedDecl *Instantiation = nullptr;
8905 NamedDecl *InstantiatedFrom = nullptr;
8906 MemberSpecializationInfo *MSInfo = nullptr;
8908 if (Previous.empty()) {
8909 // Nowhere to look anyway.
8910 } else if (FunctionDecl *Function = dyn_cast<FunctionDecl>(Member)) {
8911 for (LookupResult::iterator I = Previous.begin(), E = Previous.end();
8913 NamedDecl *D = (*I)->getUnderlyingDecl();
8914 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(D)) {
8915 QualType Adjusted = Function->getType();
8916 if (!hasExplicitCallingConv(Adjusted))
8917 Adjusted = adjustCCAndNoReturn(Adjusted, Method->getType());
8918 // This doesn't handle deduced return types, but both function
8919 // declarations should be undeduced at this point.
8920 if (Context.hasSameType(Adjusted, Method->getType())) {
8921 FoundInstantiation = *I;
8922 Instantiation = Method;
8923 InstantiatedFrom = Method->getInstantiatedFromMemberFunction();
8924 MSInfo = Method->getMemberSpecializationInfo();
8929 } else if (isa<VarDecl>(Member)) {
8931 if (Previous.isSingleResult() &&
8932 (PrevVar = dyn_cast<VarDecl>(Previous.getFoundDecl())))
8933 if (PrevVar->isStaticDataMember()) {
8934 FoundInstantiation = Previous.getRepresentativeDecl();
8935 Instantiation = PrevVar;
8936 InstantiatedFrom = PrevVar->getInstantiatedFromStaticDataMember();
8937 MSInfo = PrevVar->getMemberSpecializationInfo();
8939 } else if (isa<RecordDecl>(Member)) {
8940 CXXRecordDecl *PrevRecord;
8941 if (Previous.isSingleResult() &&
8942 (PrevRecord = dyn_cast<CXXRecordDecl>(Previous.getFoundDecl()))) {
8943 FoundInstantiation = Previous.getRepresentativeDecl();
8944 Instantiation = PrevRecord;
8945 InstantiatedFrom = PrevRecord->getInstantiatedFromMemberClass();
8946 MSInfo = PrevRecord->getMemberSpecializationInfo();
8948 } else if (isa<EnumDecl>(Member)) {
8950 if (Previous.isSingleResult() &&
8951 (PrevEnum = dyn_cast<EnumDecl>(Previous.getFoundDecl()))) {
8952 FoundInstantiation = Previous.getRepresentativeDecl();
8953 Instantiation = PrevEnum;
8954 InstantiatedFrom = PrevEnum->getInstantiatedFromMemberEnum();
8955 MSInfo = PrevEnum->getMemberSpecializationInfo();
8959 if (!Instantiation) {
8960 // There is no previous declaration that matches. Since member
8961 // specializations are always out-of-line, the caller will complain about
8962 // this mismatch later.
8966 // A member specialization in a friend declaration isn't really declaring
8967 // an explicit specialization, just identifying a specific (possibly implicit)
8968 // specialization. Don't change the template specialization kind.
8970 // FIXME: Is this really valid? Other compilers reject.
8971 if (Member->getFriendObjectKind() != Decl::FOK_None) {
8972 // Preserve instantiation information.
8973 if (InstantiatedFrom && isa<CXXMethodDecl>(Member)) {
8974 cast<CXXMethodDecl>(Member)->setInstantiationOfMemberFunction(
8975 cast<CXXMethodDecl>(InstantiatedFrom),
8976 cast<CXXMethodDecl>(Instantiation)->getTemplateSpecializationKind());
8977 } else if (InstantiatedFrom && isa<CXXRecordDecl>(Member)) {
8978 cast<CXXRecordDecl>(Member)->setInstantiationOfMemberClass(
8979 cast<CXXRecordDecl>(InstantiatedFrom),
8980 cast<CXXRecordDecl>(Instantiation)->getTemplateSpecializationKind());
8984 Previous.addDecl(FoundInstantiation);
8988 // Make sure that this is a specialization of a member.
8989 if (!InstantiatedFrom) {
8990 Diag(Member->getLocation(), diag::err_spec_member_not_instantiated)
8992 Diag(Instantiation->getLocation(), diag::note_specialized_decl);
8996 // C++ [temp.expl.spec]p6:
8997 // If a template, a member template or the member of a class template is
8998 // explicitly specialized then that specialization shall be declared
8999 // before the first use of that specialization that would cause an implicit
9000 // instantiation to take place, in every translation unit in which such a
9001 // use occurs; no diagnostic is required.
9002 assert(MSInfo && "Member specialization info missing?");
9004 bool HasNoEffect = false;
9005 if (CheckSpecializationInstantiationRedecl(Member->getLocation(),
9006 TSK_ExplicitSpecialization,
9008 MSInfo->getTemplateSpecializationKind(),
9009 MSInfo->getPointOfInstantiation(),
9013 // Check the scope of this explicit specialization.
9014 if (CheckTemplateSpecializationScope(*this,
9016 Instantiation, Member->getLocation(),
9020 // Note that this member specialization is an "instantiation of" the
9021 // corresponding member of the original template.
9022 if (auto *MemberFunction = dyn_cast<FunctionDecl>(Member)) {
9023 FunctionDecl *InstantiationFunction = cast<FunctionDecl>(Instantiation);
9024 if (InstantiationFunction->getTemplateSpecializationKind() ==
9025 TSK_ImplicitInstantiation) {
9026 // Explicit specializations of member functions of class templates do not
9027 // inherit '=delete' from the member function they are specializing.
9028 if (InstantiationFunction->isDeleted()) {
9029 // FIXME: This assert will not hold in the presence of modules.
9030 assert(InstantiationFunction->getCanonicalDecl() ==
9031 InstantiationFunction);
9032 // FIXME: We need an update record for this AST mutation.
9033 InstantiationFunction->setDeletedAsWritten(false);
9037 MemberFunction->setInstantiationOfMemberFunction(
9038 cast<CXXMethodDecl>(InstantiatedFrom), TSK_ExplicitSpecialization);
9039 } else if (auto *MemberVar = dyn_cast<VarDecl>(Member)) {
9040 MemberVar->setInstantiationOfStaticDataMember(
9041 cast<VarDecl>(InstantiatedFrom), TSK_ExplicitSpecialization);
9042 } else if (auto *MemberClass = dyn_cast<CXXRecordDecl>(Member)) {
9043 MemberClass->setInstantiationOfMemberClass(
9044 cast<CXXRecordDecl>(InstantiatedFrom), TSK_ExplicitSpecialization);
9045 } else if (auto *MemberEnum = dyn_cast<EnumDecl>(Member)) {
9046 MemberEnum->setInstantiationOfMemberEnum(
9047 cast<EnumDecl>(InstantiatedFrom), TSK_ExplicitSpecialization);
9049 llvm_unreachable("unknown member specialization kind");
9052 // Save the caller the trouble of having to figure out which declaration
9053 // this specialization matches.
9055 Previous.addDecl(FoundInstantiation);
9059 /// Complete the explicit specialization of a member of a class template by
9060 /// updating the instantiated member to be marked as an explicit specialization.
9062 /// \param OrigD The member declaration instantiated from the template.
9063 /// \param Loc The location of the explicit specialization of the member.
9064 template<typename DeclT>
9065 static void completeMemberSpecializationImpl(Sema &S, DeclT *OrigD,
9066 SourceLocation Loc) {
9067 if (OrigD->getTemplateSpecializationKind() != TSK_ImplicitInstantiation)
9070 // FIXME: Inform AST mutation listeners of this AST mutation.
9071 // FIXME: If there are multiple in-class declarations of the member (from
9072 // multiple modules, or a declaration and later definition of a member type),
9073 // should we update all of them?
9074 OrigD->setTemplateSpecializationKind(TSK_ExplicitSpecialization);
9075 OrigD->setLocation(Loc);
9078 void Sema::CompleteMemberSpecialization(NamedDecl *Member,
9079 LookupResult &Previous) {
9080 NamedDecl *Instantiation = cast<NamedDecl>(Member->getCanonicalDecl());
9081 if (Instantiation == Member)
9084 if (auto *Function = dyn_cast<CXXMethodDecl>(Instantiation))
9085 completeMemberSpecializationImpl(*this, Function, Member->getLocation());
9086 else if (auto *Var = dyn_cast<VarDecl>(Instantiation))
9087 completeMemberSpecializationImpl(*this, Var, Member->getLocation());
9088 else if (auto *Record = dyn_cast<CXXRecordDecl>(Instantiation))
9089 completeMemberSpecializationImpl(*this, Record, Member->getLocation());
9090 else if (auto *Enum = dyn_cast<EnumDecl>(Instantiation))
9091 completeMemberSpecializationImpl(*this, Enum, Member->getLocation());
9093 llvm_unreachable("unknown member specialization kind");
9096 /// Check the scope of an explicit instantiation.
9098 /// \returns true if a serious error occurs, false otherwise.
9099 static bool CheckExplicitInstantiationScope(Sema &S, NamedDecl *D,
9100 SourceLocation InstLoc,
9101 bool WasQualifiedName) {
9102 DeclContext *OrigContext= D->getDeclContext()->getEnclosingNamespaceContext();
9103 DeclContext *CurContext = S.CurContext->getRedeclContext();
9105 if (CurContext->isRecord()) {
9106 S.Diag(InstLoc, diag::err_explicit_instantiation_in_class)
9111 // C++11 [temp.explicit]p3:
9112 // An explicit instantiation shall appear in an enclosing namespace of its
9113 // template. If the name declared in the explicit instantiation is an
9114 // unqualified name, the explicit instantiation shall appear in the
9115 // namespace where its template is declared or, if that namespace is inline
9116 // (7.3.1), any namespace from its enclosing namespace set.
9118 // This is DR275, which we do not retroactively apply to C++98/03.
9119 if (WasQualifiedName) {
9120 if (CurContext->Encloses(OrigContext))
9123 if (CurContext->InEnclosingNamespaceSetOf(OrigContext))
9127 if (NamespaceDecl *NS = dyn_cast<NamespaceDecl>(OrigContext)) {
9128 if (WasQualifiedName)
9130 S.getLangOpts().CPlusPlus11?
9131 diag::err_explicit_instantiation_out_of_scope :
9132 diag::warn_explicit_instantiation_out_of_scope_0x)
9136 S.getLangOpts().CPlusPlus11?
9137 diag::err_explicit_instantiation_unqualified_wrong_namespace :
9138 diag::warn_explicit_instantiation_unqualified_wrong_namespace_0x)
9142 S.getLangOpts().CPlusPlus11?
9143 diag::err_explicit_instantiation_must_be_global :
9144 diag::warn_explicit_instantiation_must_be_global_0x)
9146 S.Diag(D->getLocation(), diag::note_explicit_instantiation_here);
9150 /// Common checks for whether an explicit instantiation of \p D is valid.
9151 static bool CheckExplicitInstantiation(Sema &S, NamedDecl *D,
9152 SourceLocation InstLoc,
9153 bool WasQualifiedName,
9154 TemplateSpecializationKind TSK) {
9155 // C++ [temp.explicit]p13:
9156 // An explicit instantiation declaration shall not name a specialization of
9157 // a template with internal linkage.
9158 if (TSK == TSK_ExplicitInstantiationDeclaration &&
9159 D->getFormalLinkage() == InternalLinkage) {
9160 S.Diag(InstLoc, diag::err_explicit_instantiation_internal_linkage) << D;
9164 // C++11 [temp.explicit]p3: [DR 275]
9165 // An explicit instantiation shall appear in an enclosing namespace of its
9167 if (CheckExplicitInstantiationScope(S, D, InstLoc, WasQualifiedName))
9173 /// Determine whether the given scope specifier has a template-id in it.
9174 static bool ScopeSpecifierHasTemplateId(const CXXScopeSpec &SS) {
9178 // C++11 [temp.explicit]p3:
9179 // If the explicit instantiation is for a member function, a member class
9180 // or a static data member of a class template specialization, the name of
9181 // the class template specialization in the qualified-id for the member
9182 // name shall be a simple-template-id.
9184 // C++98 has the same restriction, just worded differently.
9185 for (NestedNameSpecifier *NNS = SS.getScopeRep(); NNS;
9186 NNS = NNS->getPrefix())
9187 if (const Type *T = NNS->getAsType())
9188 if (isa<TemplateSpecializationType>(T))
9194 /// Make a dllexport or dllimport attr on a class template specialization take
9196 static void dllExportImportClassTemplateSpecialization(
9197 Sema &S, ClassTemplateSpecializationDecl *Def) {
9198 auto *A = cast_or_null<InheritableAttr>(getDLLAttr(Def));
9199 assert(A && "dllExportImportClassTemplateSpecialization called "
9200 "on Def without dllexport or dllimport");
9202 // We reject explicit instantiations in class scope, so there should
9203 // never be any delayed exported classes to worry about.
9204 assert(S.DelayedDllExportClasses.empty() &&
9205 "delayed exports present at explicit instantiation");
9206 S.checkClassLevelDLLAttribute(Def);
9208 // Propagate attribute to base class templates.
9209 for (auto &B : Def->bases()) {
9210 if (auto *BT = dyn_cast_or_null<ClassTemplateSpecializationDecl>(
9211 B.getType()->getAsCXXRecordDecl()))
9212 S.propagateDLLAttrToBaseClassTemplate(Def, A, BT, B.getBeginLoc());
9215 S.referenceDLLExportedClassMethods();
9218 // Explicit instantiation of a class template specialization
9219 DeclResult Sema::ActOnExplicitInstantiation(
9220 Scope *S, SourceLocation ExternLoc, SourceLocation TemplateLoc,
9221 unsigned TagSpec, SourceLocation KWLoc, const CXXScopeSpec &SS,
9222 TemplateTy TemplateD, SourceLocation TemplateNameLoc,
9223 SourceLocation LAngleLoc, ASTTemplateArgsPtr TemplateArgsIn,
9224 SourceLocation RAngleLoc, const ParsedAttributesView &Attr) {
9225 // Find the class template we're specializing
9226 TemplateName Name = TemplateD.get();
9227 TemplateDecl *TD = Name.getAsTemplateDecl();
9228 // Check that the specialization uses the same tag kind as the
9229 // original template.
9230 TagTypeKind Kind = TypeWithKeyword::getTagTypeKindForTypeSpec(TagSpec);
9231 assert(Kind != TTK_Enum &&
9232 "Invalid enum tag in class template explicit instantiation!");
9234 ClassTemplateDecl *ClassTemplate = dyn_cast<ClassTemplateDecl>(TD);
9236 if (!ClassTemplate) {
9237 NonTagKind NTK = getNonTagTypeDeclKind(TD, Kind);
9238 Diag(TemplateNameLoc, diag::err_tag_reference_non_tag) << TD << NTK << Kind;
9239 Diag(TD->getLocation(), diag::note_previous_use);
9243 if (!isAcceptableTagRedeclaration(ClassTemplate->getTemplatedDecl(),
9244 Kind, /*isDefinition*/false, KWLoc,
9245 ClassTemplate->getIdentifier())) {
9246 Diag(KWLoc, diag::err_use_with_wrong_tag)
9248 << FixItHint::CreateReplacement(KWLoc,
9249 ClassTemplate->getTemplatedDecl()->getKindName());
9250 Diag(ClassTemplate->getTemplatedDecl()->getLocation(),
9251 diag::note_previous_use);
9252 Kind = ClassTemplate->getTemplatedDecl()->getTagKind();
9255 // C++0x [temp.explicit]p2:
9256 // There are two forms of explicit instantiation: an explicit instantiation
9257 // definition and an explicit instantiation declaration. An explicit
9258 // instantiation declaration begins with the extern keyword. [...]
9259 TemplateSpecializationKind TSK = ExternLoc.isInvalid()
9260 ? TSK_ExplicitInstantiationDefinition
9261 : TSK_ExplicitInstantiationDeclaration;
9263 if (TSK == TSK_ExplicitInstantiationDeclaration &&
9264 !Context.getTargetInfo().getTriple().isWindowsGNUEnvironment()) {
9265 // Check for dllexport class template instantiation declarations,
9266 // except for MinGW mode.
9267 for (const ParsedAttr &AL : Attr) {
9268 if (AL.getKind() == ParsedAttr::AT_DLLExport) {
9270 diag::warn_attribute_dllexport_explicit_instantiation_decl);
9271 Diag(AL.getLoc(), diag::note_attribute);
9276 if (auto *A = ClassTemplate->getTemplatedDecl()->getAttr<DLLExportAttr>()) {
9278 diag::warn_attribute_dllexport_explicit_instantiation_decl);
9279 Diag(A->getLocation(), diag::note_attribute);
9283 // In MSVC mode, dllimported explicit instantiation definitions are treated as
9284 // instantiation declarations for most purposes.
9285 bool DLLImportExplicitInstantiationDef = false;
9286 if (TSK == TSK_ExplicitInstantiationDefinition &&
9287 Context.getTargetInfo().getCXXABI().isMicrosoft()) {
9288 // Check for dllimport class template instantiation definitions.
9290 ClassTemplate->getTemplatedDecl()->getAttr<DLLImportAttr>();
9291 for (const ParsedAttr &AL : Attr) {
9292 if (AL.getKind() == ParsedAttr::AT_DLLImport)
9294 if (AL.getKind() == ParsedAttr::AT_DLLExport) {
9295 // dllexport trumps dllimport here.
9301 TSK = TSK_ExplicitInstantiationDeclaration;
9302 DLLImportExplicitInstantiationDef = true;
9306 // Translate the parser's template argument list in our AST format.
9307 TemplateArgumentListInfo TemplateArgs(LAngleLoc, RAngleLoc);
9308 translateTemplateArguments(TemplateArgsIn, TemplateArgs);
9310 // Check that the template argument list is well-formed for this
9312 SmallVector<TemplateArgument, 4> Converted;
9313 if (CheckTemplateArgumentList(ClassTemplate, TemplateNameLoc,
9314 TemplateArgs, false, Converted,
9315 /*UpdateArgsWithConversion=*/true))
9318 // Find the class template specialization declaration that
9319 // corresponds to these arguments.
9320 void *InsertPos = nullptr;
9321 ClassTemplateSpecializationDecl *PrevDecl
9322 = ClassTemplate->findSpecialization(Converted, InsertPos);
9324 TemplateSpecializationKind PrevDecl_TSK
9325 = PrevDecl ? PrevDecl->getTemplateSpecializationKind() : TSK_Undeclared;
9327 if (TSK == TSK_ExplicitInstantiationDefinition && PrevDecl != nullptr &&
9328 Context.getTargetInfo().getTriple().isWindowsGNUEnvironment()) {
9329 // Check for dllexport class template instantiation definitions in MinGW
9330 // mode, if a previous declaration of the instantiation was seen.
9331 for (const ParsedAttr &AL : Attr) {
9332 if (AL.getKind() == ParsedAttr::AT_DLLExport) {
9334 diag::warn_attribute_dllexport_explicit_instantiation_def);
9340 if (CheckExplicitInstantiation(*this, ClassTemplate, TemplateNameLoc,
9344 ClassTemplateSpecializationDecl *Specialization = nullptr;
9346 bool HasNoEffect = false;
9348 if (CheckSpecializationInstantiationRedecl(TemplateNameLoc, TSK,
9349 PrevDecl, PrevDecl_TSK,
9350 PrevDecl->getPointOfInstantiation(),
9354 // Even though HasNoEffect == true means that this explicit instantiation
9355 // has no effect on semantics, we go on to put its syntax in the AST.
9357 if (PrevDecl_TSK == TSK_ImplicitInstantiation ||
9358 PrevDecl_TSK == TSK_Undeclared) {
9359 // Since the only prior class template specialization with these
9360 // arguments was referenced but not declared, reuse that
9361 // declaration node as our own, updating the source location
9362 // for the template name to reflect our new declaration.
9363 // (Other source locations will be updated later.)
9364 Specialization = PrevDecl;
9365 Specialization->setLocation(TemplateNameLoc);
9369 if (PrevDecl_TSK == TSK_ExplicitInstantiationDeclaration &&
9370 DLLImportExplicitInstantiationDef) {
9371 // The new specialization might add a dllimport attribute.
9372 HasNoEffect = false;
9376 if (!Specialization) {
9377 // Create a new class template specialization declaration node for
9378 // this explicit specialization.
9380 = ClassTemplateSpecializationDecl::Create(Context, Kind,
9381 ClassTemplate->getDeclContext(),
9382 KWLoc, TemplateNameLoc,
9386 SetNestedNameSpecifier(*this, Specialization, SS);
9388 if (!HasNoEffect && !PrevDecl) {
9389 // Insert the new specialization.
9390 ClassTemplate->AddSpecialization(Specialization, InsertPos);
9394 // Build the fully-sugared type for this explicit instantiation as
9395 // the user wrote in the explicit instantiation itself. This means
9396 // that we'll pretty-print the type retrieved from the
9397 // specialization's declaration the way that the user actually wrote
9398 // the explicit instantiation, rather than formatting the name based
9399 // on the "canonical" representation used to store the template
9400 // arguments in the specialization.
9401 TypeSourceInfo *WrittenTy
9402 = Context.getTemplateSpecializationTypeInfo(Name, TemplateNameLoc,
9404 Context.getTypeDeclType(Specialization));
9405 Specialization->setTypeAsWritten(WrittenTy);
9407 // Set source locations for keywords.
9408 Specialization->setExternLoc(ExternLoc);
9409 Specialization->setTemplateKeywordLoc(TemplateLoc);
9410 Specialization->setBraceRange(SourceRange());
9412 bool PreviouslyDLLExported = Specialization->hasAttr<DLLExportAttr>();
9413 ProcessDeclAttributeList(S, Specialization, Attr);
9415 // Add the explicit instantiation into its lexical context. However,
9416 // since explicit instantiations are never found by name lookup, we
9417 // just put it into the declaration context directly.
9418 Specialization->setLexicalDeclContext(CurContext);
9419 CurContext->addDecl(Specialization);
9421 // Syntax is now OK, so return if it has no other effect on semantics.
9423 // Set the template specialization kind.
9424 Specialization->setTemplateSpecializationKind(TSK);
9425 return Specialization;
9428 // C++ [temp.explicit]p3:
9429 // A definition of a class template or class member template
9430 // shall be in scope at the point of the explicit instantiation of
9431 // the class template or class member template.
9433 // This check comes when we actually try to perform the
9435 ClassTemplateSpecializationDecl *Def
9436 = cast_or_null<ClassTemplateSpecializationDecl>(
9437 Specialization->getDefinition());
9439 InstantiateClassTemplateSpecialization(TemplateNameLoc, Specialization, TSK);
9440 else if (TSK == TSK_ExplicitInstantiationDefinition) {
9441 MarkVTableUsed(TemplateNameLoc, Specialization, true);
9442 Specialization->setPointOfInstantiation(Def->getPointOfInstantiation());
9445 // Instantiate the members of this class template specialization.
9446 Def = cast_or_null<ClassTemplateSpecializationDecl>(
9447 Specialization->getDefinition());
9449 TemplateSpecializationKind Old_TSK = Def->getTemplateSpecializationKind();
9450 // Fix a TSK_ExplicitInstantiationDeclaration followed by a
9451 // TSK_ExplicitInstantiationDefinition
9452 if (Old_TSK == TSK_ExplicitInstantiationDeclaration &&
9453 (TSK == TSK_ExplicitInstantiationDefinition ||
9454 DLLImportExplicitInstantiationDef)) {
9455 // FIXME: Need to notify the ASTMutationListener that we did this.
9456 Def->setTemplateSpecializationKind(TSK);
9458 if (!getDLLAttr(Def) && getDLLAttr(Specialization) &&
9459 (Context.getTargetInfo().getCXXABI().isMicrosoft() ||
9460 Context.getTargetInfo().getTriple().isWindowsItaniumEnvironment())) {
9461 // In the MS ABI, an explicit instantiation definition can add a dll
9462 // attribute to a template with a previous instantiation declaration.
9463 // MinGW doesn't allow this.
9464 auto *A = cast<InheritableAttr>(
9465 getDLLAttr(Specialization)->clone(getASTContext()));
9466 A->setInherited(true);
9468 dllExportImportClassTemplateSpecialization(*this, Def);
9472 // Fix a TSK_ImplicitInstantiation followed by a
9473 // TSK_ExplicitInstantiationDefinition
9474 bool NewlyDLLExported =
9475 !PreviouslyDLLExported && Specialization->hasAttr<DLLExportAttr>();
9476 if (Old_TSK == TSK_ImplicitInstantiation && NewlyDLLExported &&
9477 (Context.getTargetInfo().getCXXABI().isMicrosoft() ||
9478 Context.getTargetInfo().getTriple().isWindowsItaniumEnvironment())) {
9479 // In the MS ABI, an explicit instantiation definition can add a dll
9480 // attribute to a template with a previous implicit instantiation.
9481 // MinGW doesn't allow this. We limit clang to only adding dllexport, to
9482 // avoid potentially strange codegen behavior. For example, if we extend
9483 // this conditional to dllimport, and we have a source file calling a
9484 // method on an implicitly instantiated template class instance and then
9485 // declaring a dllimport explicit instantiation definition for the same
9486 // template class, the codegen for the method call will not respect the
9487 // dllimport, while it will with cl. The Def will already have the DLL
9488 // attribute, since the Def and Specialization will be the same in the
9489 // case of Old_TSK == TSK_ImplicitInstantiation, and we already added the
9490 // attribute to the Specialization; we just need to make it take effect.
9491 assert(Def == Specialization &&
9492 "Def and Specialization should match for implicit instantiation");
9493 dllExportImportClassTemplateSpecialization(*this, Def);
9496 // In MinGW mode, export the template instantiation if the declaration
9497 // was marked dllexport.
9498 if (PrevDecl_TSK == TSK_ExplicitInstantiationDeclaration &&
9499 Context.getTargetInfo().getTriple().isWindowsGNUEnvironment() &&
9500 PrevDecl->hasAttr<DLLExportAttr>()) {
9501 dllExportImportClassTemplateSpecialization(*this, Def);
9504 // Set the template specialization kind. Make sure it is set before
9505 // instantiating the members which will trigger ASTConsumer callbacks.
9506 Specialization->setTemplateSpecializationKind(TSK);
9507 InstantiateClassTemplateSpecializationMembers(TemplateNameLoc, Def, TSK);
9510 // Set the template specialization kind.
9511 Specialization->setTemplateSpecializationKind(TSK);
9514 return Specialization;
9517 // Explicit instantiation of a member class of a class template.
9519 Sema::ActOnExplicitInstantiation(Scope *S, SourceLocation ExternLoc,
9520 SourceLocation TemplateLoc, unsigned TagSpec,
9521 SourceLocation KWLoc, CXXScopeSpec &SS,
9522 IdentifierInfo *Name, SourceLocation NameLoc,
9523 const ParsedAttributesView &Attr) {
9526 bool IsDependent = false;
9527 Decl *TagD = ActOnTag(S, TagSpec, Sema::TUK_Reference,
9528 KWLoc, SS, Name, NameLoc, Attr, AS_none,
9529 /*ModulePrivateLoc=*/SourceLocation(),
9530 MultiTemplateParamsArg(), Owned, IsDependent,
9531 SourceLocation(), false, TypeResult(),
9532 /*IsTypeSpecifier*/false,
9533 /*IsTemplateParamOrArg*/false);
9534 assert(!IsDependent && "explicit instantiation of dependent name not yet handled");
9539 TagDecl *Tag = cast<TagDecl>(TagD);
9540 assert(!Tag->isEnum() && "shouldn't see enumerations here");
9542 if (Tag->isInvalidDecl())
9545 CXXRecordDecl *Record = cast<CXXRecordDecl>(Tag);
9546 CXXRecordDecl *Pattern = Record->getInstantiatedFromMemberClass();
9548 Diag(TemplateLoc, diag::err_explicit_instantiation_nontemplate_type)
9549 << Context.getTypeDeclType(Record);
9550 Diag(Record->getLocation(), diag::note_nontemplate_decl_here);
9554 // C++0x [temp.explicit]p2:
9555 // If the explicit instantiation is for a class or member class, the
9556 // elaborated-type-specifier in the declaration shall include a
9557 // simple-template-id.
9559 // C++98 has the same restriction, just worded differently.
9560 if (!ScopeSpecifierHasTemplateId(SS))
9561 Diag(TemplateLoc, diag::ext_explicit_instantiation_without_qualified_id)
9562 << Record << SS.getRange();
9564 // C++0x [temp.explicit]p2:
9565 // There are two forms of explicit instantiation: an explicit instantiation
9566 // definition and an explicit instantiation declaration. An explicit
9567 // instantiation declaration begins with the extern keyword. [...]
9568 TemplateSpecializationKind TSK
9569 = ExternLoc.isInvalid()? TSK_ExplicitInstantiationDefinition
9570 : TSK_ExplicitInstantiationDeclaration;
9572 CheckExplicitInstantiation(*this, Record, NameLoc, true, TSK);
9574 // Verify that it is okay to explicitly instantiate here.
9575 CXXRecordDecl *PrevDecl
9576 = cast_or_null<CXXRecordDecl>(Record->getPreviousDecl());
9577 if (!PrevDecl && Record->getDefinition())
9580 MemberSpecializationInfo *MSInfo = PrevDecl->getMemberSpecializationInfo();
9581 bool HasNoEffect = false;
9582 assert(MSInfo && "No member specialization information?");
9583 if (CheckSpecializationInstantiationRedecl(TemplateLoc, TSK,
9585 MSInfo->getTemplateSpecializationKind(),
9586 MSInfo->getPointOfInstantiation(),
9593 CXXRecordDecl *RecordDef
9594 = cast_or_null<CXXRecordDecl>(Record->getDefinition());
9596 // C++ [temp.explicit]p3:
9597 // A definition of a member class of a class template shall be in scope
9598 // at the point of an explicit instantiation of the member class.
9600 = cast_or_null<CXXRecordDecl>(Pattern->getDefinition());
9602 Diag(TemplateLoc, diag::err_explicit_instantiation_undefined_member)
9603 << 0 << Record->getDeclName() << Record->getDeclContext();
9604 Diag(Pattern->getLocation(), diag::note_forward_declaration)
9608 if (InstantiateClass(NameLoc, Record, Def,
9609 getTemplateInstantiationArgs(Record),
9613 RecordDef = cast_or_null<CXXRecordDecl>(Record->getDefinition());
9619 // Instantiate all of the members of the class.
9620 InstantiateClassMembers(NameLoc, RecordDef,
9621 getTemplateInstantiationArgs(Record), TSK);
9623 if (TSK == TSK_ExplicitInstantiationDefinition)
9624 MarkVTableUsed(NameLoc, RecordDef, true);
9626 // FIXME: We don't have any representation for explicit instantiations of
9627 // member classes. Such a representation is not needed for compilation, but it
9628 // should be available for clients that want to see all of the declarations in
9633 DeclResult Sema::ActOnExplicitInstantiation(Scope *S,
9634 SourceLocation ExternLoc,
9635 SourceLocation TemplateLoc,
9637 // Explicit instantiations always require a name.
9638 // TODO: check if/when DNInfo should replace Name.
9639 DeclarationNameInfo NameInfo = GetNameForDeclarator(D);
9640 DeclarationName Name = NameInfo.getName();
9642 if (!D.isInvalidType())
9643 Diag(D.getDeclSpec().getBeginLoc(),
9644 diag::err_explicit_instantiation_requires_name)
9645 << D.getDeclSpec().getSourceRange() << D.getSourceRange();
9650 // The scope passed in may not be a decl scope. Zip up the scope tree until
9651 // we find one that is.
9652 while ((S->getFlags() & Scope::DeclScope) == 0 ||
9653 (S->getFlags() & Scope::TemplateParamScope) != 0)
9656 // Determine the type of the declaration.
9657 TypeSourceInfo *T = GetTypeForDeclarator(D, S);
9658 QualType R = T->getType();
9663 // A storage-class-specifier shall not be specified in [...] an explicit
9664 // instantiation (14.7.2) directive.
9665 if (D.getDeclSpec().getStorageClassSpec() == DeclSpec::SCS_typedef) {
9666 Diag(D.getIdentifierLoc(), diag::err_explicit_instantiation_of_typedef)
9669 } else if (D.getDeclSpec().getStorageClassSpec()
9670 != DeclSpec::SCS_unspecified) {
9671 // Complain about then remove the storage class specifier.
9672 Diag(D.getIdentifierLoc(), diag::err_explicit_instantiation_storage_class)
9673 << FixItHint::CreateRemoval(D.getDeclSpec().getStorageClassSpecLoc());
9675 D.getMutableDeclSpec().ClearStorageClassSpecs();
9678 // C++0x [temp.explicit]p1:
9679 // [...] An explicit instantiation of a function template shall not use the
9680 // inline or constexpr specifiers.
9681 // Presumably, this also applies to member functions of class templates as
9683 if (D.getDeclSpec().isInlineSpecified())
9684 Diag(D.getDeclSpec().getInlineSpecLoc(),
9685 getLangOpts().CPlusPlus11 ?
9686 diag::err_explicit_instantiation_inline :
9687 diag::warn_explicit_instantiation_inline_0x)
9688 << FixItHint::CreateRemoval(D.getDeclSpec().getInlineSpecLoc());
9689 if (D.getDeclSpec().hasConstexprSpecifier() && R->isFunctionType())
9690 // FIXME: Add a fix-it to remove the 'constexpr' and add a 'const' if one is
9691 // not already specified.
9692 Diag(D.getDeclSpec().getConstexprSpecLoc(),
9693 diag::err_explicit_instantiation_constexpr);
9695 // A deduction guide is not on the list of entities that can be explicitly
9697 if (Name.getNameKind() == DeclarationName::CXXDeductionGuideName) {
9698 Diag(D.getDeclSpec().getBeginLoc(), diag::err_deduction_guide_specialized)
9699 << /*explicit instantiation*/ 0;
9703 // C++0x [temp.explicit]p2:
9704 // There are two forms of explicit instantiation: an explicit instantiation
9705 // definition and an explicit instantiation declaration. An explicit
9706 // instantiation declaration begins with the extern keyword. [...]
9707 TemplateSpecializationKind TSK
9708 = ExternLoc.isInvalid()? TSK_ExplicitInstantiationDefinition
9709 : TSK_ExplicitInstantiationDeclaration;
9711 LookupResult Previous(*this, NameInfo, LookupOrdinaryName);
9712 LookupParsedName(Previous, S, &D.getCXXScopeSpec());
9714 if (!R->isFunctionType()) {
9715 // C++ [temp.explicit]p1:
9716 // A [...] static data member of a class template can be explicitly
9717 // instantiated from the member definition associated with its class
9719 // C++1y [temp.explicit]p1:
9720 // A [...] variable [...] template specialization can be explicitly
9721 // instantiated from its template.
9722 if (Previous.isAmbiguous())
9725 VarDecl *Prev = Previous.getAsSingle<VarDecl>();
9726 VarTemplateDecl *PrevTemplate = Previous.getAsSingle<VarTemplateDecl>();
9728 if (!PrevTemplate) {
9729 if (!Prev || !Prev->isStaticDataMember()) {
9730 // We expect to see a static data member here.
9731 Diag(D.getIdentifierLoc(), diag::err_explicit_instantiation_not_known)
9733 for (LookupResult::iterator P = Previous.begin(), PEnd = Previous.end();
9735 Diag((*P)->getLocation(), diag::note_explicit_instantiation_here);
9739 if (!Prev->getInstantiatedFromStaticDataMember()) {
9740 // FIXME: Check for explicit specialization?
9741 Diag(D.getIdentifierLoc(),
9742 diag::err_explicit_instantiation_data_member_not_instantiated)
9744 Diag(Prev->getLocation(), diag::note_explicit_instantiation_here);
9745 // FIXME: Can we provide a note showing where this was declared?
9749 // Explicitly instantiate a variable template.
9751 // C++1y [dcl.spec.auto]p6:
9752 // ... A program that uses auto or decltype(auto) in a context not
9753 // explicitly allowed in this section is ill-formed.
9755 // This includes auto-typed variable template instantiations.
9756 if (R->isUndeducedType()) {
9757 Diag(T->getTypeLoc().getBeginLoc(),
9758 diag::err_auto_not_allowed_var_inst);
9762 if (D.getName().getKind() != UnqualifiedIdKind::IK_TemplateId) {
9763 // C++1y [temp.explicit]p3:
9764 // If the explicit instantiation is for a variable, the unqualified-id
9765 // in the declaration shall be a template-id.
9766 Diag(D.getIdentifierLoc(),
9767 diag::err_explicit_instantiation_without_template_id)
9769 Diag(PrevTemplate->getLocation(),
9770 diag::note_explicit_instantiation_here);
9774 // Translate the parser's template argument list into our AST format.
9775 TemplateArgumentListInfo TemplateArgs =
9776 makeTemplateArgumentListInfo(*this, *D.getName().TemplateId);
9778 DeclResult Res = CheckVarTemplateId(PrevTemplate, TemplateLoc,
9779 D.getIdentifierLoc(), TemplateArgs);
9780 if (Res.isInvalid())
9783 // Ignore access control bits, we don't need them for redeclaration
9785 Prev = cast<VarDecl>(Res.get());
9788 // C++0x [temp.explicit]p2:
9789 // If the explicit instantiation is for a member function, a member class
9790 // or a static data member of a class template specialization, the name of
9791 // the class template specialization in the qualified-id for the member
9792 // name shall be a simple-template-id.
9794 // C++98 has the same restriction, just worded differently.
9796 // This does not apply to variable template specializations, where the
9797 // template-id is in the unqualified-id instead.
9798 if (!ScopeSpecifierHasTemplateId(D.getCXXScopeSpec()) && !PrevTemplate)
9799 Diag(D.getIdentifierLoc(),
9800 diag::ext_explicit_instantiation_without_qualified_id)
9801 << Prev << D.getCXXScopeSpec().getRange();
9803 CheckExplicitInstantiation(*this, Prev, D.getIdentifierLoc(), true, TSK);
9805 // Verify that it is okay to explicitly instantiate here.
9806 TemplateSpecializationKind PrevTSK = Prev->getTemplateSpecializationKind();
9807 SourceLocation POI = Prev->getPointOfInstantiation();
9808 bool HasNoEffect = false;
9809 if (CheckSpecializationInstantiationRedecl(D.getIdentifierLoc(), TSK, Prev,
9810 PrevTSK, POI, HasNoEffect))
9814 // Instantiate static data member or variable template.
9815 Prev->setTemplateSpecializationKind(TSK, D.getIdentifierLoc());
9816 // Merge attributes.
9817 ProcessDeclAttributeList(S, Prev, D.getDeclSpec().getAttributes());
9818 if (TSK == TSK_ExplicitInstantiationDefinition)
9819 InstantiateVariableDefinition(D.getIdentifierLoc(), Prev);
9822 // Check the new variable specialization against the parsed input.
9823 if (PrevTemplate && Prev && !Context.hasSameType(Prev->getType(), R)) {
9824 Diag(T->getTypeLoc().getBeginLoc(),
9825 diag::err_invalid_var_template_spec_type)
9826 << 0 << PrevTemplate << R << Prev->getType();
9827 Diag(PrevTemplate->getLocation(), diag::note_template_declared_here)
9828 << 2 << PrevTemplate->getDeclName();
9832 // FIXME: Create an ExplicitInstantiation node?
9833 return (Decl*) nullptr;
9836 // If the declarator is a template-id, translate the parser's template
9837 // argument list into our AST format.
9838 bool HasExplicitTemplateArgs = false;
9839 TemplateArgumentListInfo TemplateArgs;
9840 if (D.getName().getKind() == UnqualifiedIdKind::IK_TemplateId) {
9841 TemplateArgs = makeTemplateArgumentListInfo(*this, *D.getName().TemplateId);
9842 HasExplicitTemplateArgs = true;
9845 // C++ [temp.explicit]p1:
9846 // A [...] function [...] can be explicitly instantiated from its template.
9847 // A member function [...] of a class template can be explicitly
9848 // instantiated from the member definition associated with its class
9850 UnresolvedSet<8> TemplateMatches;
9851 FunctionDecl *NonTemplateMatch = nullptr;
9852 TemplateSpecCandidateSet FailedCandidates(D.getIdentifierLoc());
9853 for (LookupResult::iterator P = Previous.begin(), PEnd = Previous.end();
9855 NamedDecl *Prev = *P;
9856 if (!HasExplicitTemplateArgs) {
9857 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Prev)) {
9858 QualType Adjusted = adjustCCAndNoReturn(R, Method->getType(),
9859 /*AdjustExceptionSpec*/true);
9860 if (Context.hasSameUnqualifiedType(Method->getType(), Adjusted)) {
9861 if (Method->getPrimaryTemplate()) {
9862 TemplateMatches.addDecl(Method, P.getAccess());
9864 // FIXME: Can this assert ever happen? Needs a test.
9865 assert(!NonTemplateMatch && "Multiple NonTemplateMatches");
9866 NonTemplateMatch = Method;
9872 FunctionTemplateDecl *FunTmpl = dyn_cast<FunctionTemplateDecl>(Prev);
9876 TemplateDeductionInfo Info(FailedCandidates.getLocation());
9877 FunctionDecl *Specialization = nullptr;
9878 if (TemplateDeductionResult TDK
9879 = DeduceTemplateArguments(FunTmpl,
9880 (HasExplicitTemplateArgs ? &TemplateArgs
9882 R, Specialization, Info)) {
9883 // Keep track of almost-matches.
9884 FailedCandidates.addCandidate()
9885 .set(P.getPair(), FunTmpl->getTemplatedDecl(),
9886 MakeDeductionFailureInfo(Context, TDK, Info));
9891 // Target attributes are part of the cuda function signature, so
9892 // the cuda target of the instantiated function must match that of its
9893 // template. Given that C++ template deduction does not take
9894 // target attributes into account, we reject candidates here that
9895 // have a different target.
9896 if (LangOpts.CUDA &&
9897 IdentifyCUDATarget(Specialization,
9898 /* IgnoreImplicitHDAttr = */ true) !=
9899 IdentifyCUDATarget(D.getDeclSpec().getAttributes())) {
9900 FailedCandidates.addCandidate().set(
9901 P.getPair(), FunTmpl->getTemplatedDecl(),
9902 MakeDeductionFailureInfo(Context, TDK_CUDATargetMismatch, Info));
9906 TemplateMatches.addDecl(Specialization, P.getAccess());
9909 FunctionDecl *Specialization = NonTemplateMatch;
9910 if (!Specialization) {
9911 // Find the most specialized function template specialization.
9912 UnresolvedSetIterator Result = getMostSpecialized(
9913 TemplateMatches.begin(), TemplateMatches.end(), FailedCandidates,
9914 D.getIdentifierLoc(),
9915 PDiag(diag::err_explicit_instantiation_not_known) << Name,
9916 PDiag(diag::err_explicit_instantiation_ambiguous) << Name,
9917 PDiag(diag::note_explicit_instantiation_candidate));
9919 if (Result == TemplateMatches.end())
9922 // Ignore access control bits, we don't need them for redeclaration checking.
9923 Specialization = cast<FunctionDecl>(*Result);
9926 // C++11 [except.spec]p4
9927 // In an explicit instantiation an exception-specification may be specified,
9928 // but is not required.
9929 // If an exception-specification is specified in an explicit instantiation
9930 // directive, it shall be compatible with the exception-specifications of
9931 // other declarations of that function.
9932 if (auto *FPT = R->getAs<FunctionProtoType>())
9933 if (FPT->hasExceptionSpec()) {
9935 diag::err_mismatched_exception_spec_explicit_instantiation;
9936 if (getLangOpts().MicrosoftExt)
9937 DiagID = diag::ext_mismatched_exception_spec_explicit_instantiation;
9938 bool Result = CheckEquivalentExceptionSpec(
9939 PDiag(DiagID) << Specialization->getType(),
9940 PDiag(diag::note_explicit_instantiation_here),
9941 Specialization->getType()->getAs<FunctionProtoType>(),
9942 Specialization->getLocation(), FPT, D.getBeginLoc());
9943 // In Microsoft mode, mismatching exception specifications just cause a
9945 if (!getLangOpts().MicrosoftExt && Result)
9949 if (Specialization->getTemplateSpecializationKind() == TSK_Undeclared) {
9950 Diag(D.getIdentifierLoc(),
9951 diag::err_explicit_instantiation_member_function_not_instantiated)
9953 << (Specialization->getTemplateSpecializationKind() ==
9954 TSK_ExplicitSpecialization);
9955 Diag(Specialization->getLocation(), diag::note_explicit_instantiation_here);
9959 FunctionDecl *PrevDecl = Specialization->getPreviousDecl();
9960 if (!PrevDecl && Specialization->isThisDeclarationADefinition())
9961 PrevDecl = Specialization;
9964 bool HasNoEffect = false;
9965 if (CheckSpecializationInstantiationRedecl(D.getIdentifierLoc(), TSK,
9967 PrevDecl->getTemplateSpecializationKind(),
9968 PrevDecl->getPointOfInstantiation(),
9972 // FIXME: We may still want to build some representation of this
9973 // explicit specialization.
9975 return (Decl*) nullptr;
9978 // HACK: libc++ has a bug where it attempts to explicitly instantiate the
9980 // valarray<size_t>::valarray(size_t) and
9981 // valarray<size_t>::~valarray()
9982 // that it declared to have internal linkage with the internal_linkage
9983 // attribute. Ignore the explicit instantiation declaration in this case.
9984 if (Specialization->hasAttr<InternalLinkageAttr>() &&
9985 TSK == TSK_ExplicitInstantiationDeclaration) {
9986 if (auto *RD = dyn_cast<CXXRecordDecl>(Specialization->getDeclContext()))
9987 if (RD->getIdentifier() && RD->getIdentifier()->isStr("valarray") &&
9988 RD->isInStdNamespace())
9989 return (Decl*) nullptr;
9992 ProcessDeclAttributeList(S, Specialization, D.getDeclSpec().getAttributes());
9994 // In MSVC mode, dllimported explicit instantiation definitions are treated as
9995 // instantiation declarations.
9996 if (TSK == TSK_ExplicitInstantiationDefinition &&
9997 Specialization->hasAttr<DLLImportAttr>() &&
9998 Context.getTargetInfo().getCXXABI().isMicrosoft())
9999 TSK = TSK_ExplicitInstantiationDeclaration;
10001 Specialization->setTemplateSpecializationKind(TSK, D.getIdentifierLoc());
10003 if (Specialization->isDefined()) {
10004 // Let the ASTConsumer know that this function has been explicitly
10005 // instantiated now, and its linkage might have changed.
10006 Consumer.HandleTopLevelDecl(DeclGroupRef(Specialization));
10007 } else if (TSK == TSK_ExplicitInstantiationDefinition)
10008 InstantiateFunctionDefinition(D.getIdentifierLoc(), Specialization);
10010 // C++0x [temp.explicit]p2:
10011 // If the explicit instantiation is for a member function, a member class
10012 // or a static data member of a class template specialization, the name of
10013 // the class template specialization in the qualified-id for the member
10014 // name shall be a simple-template-id.
10016 // C++98 has the same restriction, just worded differently.
10017 FunctionTemplateDecl *FunTmpl = Specialization->getPrimaryTemplate();
10018 if (D.getName().getKind() != UnqualifiedIdKind::IK_TemplateId && !FunTmpl &&
10019 D.getCXXScopeSpec().isSet() &&
10020 !ScopeSpecifierHasTemplateId(D.getCXXScopeSpec()))
10021 Diag(D.getIdentifierLoc(),
10022 diag::ext_explicit_instantiation_without_qualified_id)
10023 << Specialization << D.getCXXScopeSpec().getRange();
10025 CheckExplicitInstantiation(
10027 FunTmpl ? (NamedDecl *)FunTmpl
10028 : Specialization->getInstantiatedFromMemberFunction(),
10029 D.getIdentifierLoc(), D.getCXXScopeSpec().isSet(), TSK);
10031 // FIXME: Create some kind of ExplicitInstantiationDecl here.
10032 return (Decl*) nullptr;
10036 Sema::ActOnDependentTag(Scope *S, unsigned TagSpec, TagUseKind TUK,
10037 const CXXScopeSpec &SS, IdentifierInfo *Name,
10038 SourceLocation TagLoc, SourceLocation NameLoc) {
10039 // This has to hold, because SS is expected to be defined.
10040 assert(Name && "Expected a name in a dependent tag");
10042 NestedNameSpecifier *NNS = SS.getScopeRep();
10046 TagTypeKind Kind = TypeWithKeyword::getTagTypeKindForTypeSpec(TagSpec);
10048 if (TUK == TUK_Declaration || TUK == TUK_Definition) {
10049 Diag(NameLoc, diag::err_dependent_tag_decl)
10050 << (TUK == TUK_Definition) << Kind << SS.getRange();
10054 // Create the resulting type.
10055 ElaboratedTypeKeyword Kwd = TypeWithKeyword::getKeywordForTagTypeKind(Kind);
10056 QualType Result = Context.getDependentNameType(Kwd, NNS, Name);
10058 // Create type-source location information for this type.
10059 TypeLocBuilder TLB;
10060 DependentNameTypeLoc TL = TLB.push<DependentNameTypeLoc>(Result);
10061 TL.setElaboratedKeywordLoc(TagLoc);
10062 TL.setQualifierLoc(SS.getWithLocInContext(Context));
10063 TL.setNameLoc(NameLoc);
10064 return CreateParsedType(Result, TLB.getTypeSourceInfo(Context, Result));
10068 Sema::ActOnTypenameType(Scope *S, SourceLocation TypenameLoc,
10069 const CXXScopeSpec &SS, const IdentifierInfo &II,
10070 SourceLocation IdLoc) {
10071 if (SS.isInvalid())
10074 if (TypenameLoc.isValid() && S && !S->getTemplateParamParent())
10076 getLangOpts().CPlusPlus11 ?
10077 diag::warn_cxx98_compat_typename_outside_of_template :
10078 diag::ext_typename_outside_of_template)
10079 << FixItHint::CreateRemoval(TypenameLoc);
10081 NestedNameSpecifierLoc QualifierLoc = SS.getWithLocInContext(Context);
10082 TypeSourceInfo *TSI = nullptr;
10083 QualType T = CheckTypenameType(TypenameLoc.isValid()? ETK_Typename : ETK_None,
10084 TypenameLoc, QualifierLoc, II, IdLoc, &TSI,
10085 /*DeducedTSTContext=*/true);
10088 return CreateParsedType(T, TSI);
10092 Sema::ActOnTypenameType(Scope *S,
10093 SourceLocation TypenameLoc,
10094 const CXXScopeSpec &SS,
10095 SourceLocation TemplateKWLoc,
10096 TemplateTy TemplateIn,
10097 IdentifierInfo *TemplateII,
10098 SourceLocation TemplateIILoc,
10099 SourceLocation LAngleLoc,
10100 ASTTemplateArgsPtr TemplateArgsIn,
10101 SourceLocation RAngleLoc) {
10102 if (TypenameLoc.isValid() && S && !S->getTemplateParamParent())
10104 getLangOpts().CPlusPlus11 ?
10105 diag::warn_cxx98_compat_typename_outside_of_template :
10106 diag::ext_typename_outside_of_template)
10107 << FixItHint::CreateRemoval(TypenameLoc);
10109 // Strangely, non-type results are not ignored by this lookup, so the
10110 // program is ill-formed if it finds an injected-class-name.
10111 if (TypenameLoc.isValid()) {
10113 dyn_cast_or_null<CXXRecordDecl>(computeDeclContext(SS, false));
10114 if (LookupRD && LookupRD->getIdentifier() == TemplateII) {
10115 Diag(TemplateIILoc,
10116 diag::ext_out_of_line_qualified_id_type_names_constructor)
10117 << TemplateII << 0 /*injected-class-name used as template name*/
10118 << (TemplateKWLoc.isValid() ? 1 : 0 /*'template'/'typename' keyword*/);
10122 // Translate the parser's template argument list in our AST format.
10123 TemplateArgumentListInfo TemplateArgs(LAngleLoc, RAngleLoc);
10124 translateTemplateArguments(TemplateArgsIn, TemplateArgs);
10126 TemplateName Template = TemplateIn.get();
10127 if (DependentTemplateName *DTN = Template.getAsDependentTemplateName()) {
10128 // Construct a dependent template specialization type.
10129 assert(DTN && "dependent template has non-dependent name?");
10130 assert(DTN->getQualifier() == SS.getScopeRep());
10131 QualType T = Context.getDependentTemplateSpecializationType(ETK_Typename,
10132 DTN->getQualifier(),
10133 DTN->getIdentifier(),
10136 // Create source-location information for this type.
10137 TypeLocBuilder Builder;
10138 DependentTemplateSpecializationTypeLoc SpecTL
10139 = Builder.push<DependentTemplateSpecializationTypeLoc>(T);
10140 SpecTL.setElaboratedKeywordLoc(TypenameLoc);
10141 SpecTL.setQualifierLoc(SS.getWithLocInContext(Context));
10142 SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
10143 SpecTL.setTemplateNameLoc(TemplateIILoc);
10144 SpecTL.setLAngleLoc(LAngleLoc);
10145 SpecTL.setRAngleLoc(RAngleLoc);
10146 for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I)
10147 SpecTL.setArgLocInfo(I, TemplateArgs[I].getLocInfo());
10148 return CreateParsedType(T, Builder.getTypeSourceInfo(Context, T));
10151 QualType T = CheckTemplateIdType(Template, TemplateIILoc, TemplateArgs);
10155 // Provide source-location information for the template specialization type.
10156 TypeLocBuilder Builder;
10157 TemplateSpecializationTypeLoc SpecTL
10158 = Builder.push<TemplateSpecializationTypeLoc>(T);
10159 SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
10160 SpecTL.setTemplateNameLoc(TemplateIILoc);
10161 SpecTL.setLAngleLoc(LAngleLoc);
10162 SpecTL.setRAngleLoc(RAngleLoc);
10163 for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I)
10164 SpecTL.setArgLocInfo(I, TemplateArgs[I].getLocInfo());
10166 T = Context.getElaboratedType(ETK_Typename, SS.getScopeRep(), T);
10167 ElaboratedTypeLoc TL = Builder.push<ElaboratedTypeLoc>(T);
10168 TL.setElaboratedKeywordLoc(TypenameLoc);
10169 TL.setQualifierLoc(SS.getWithLocInContext(Context));
10171 TypeSourceInfo *TSI = Builder.getTypeSourceInfo(Context, T);
10172 return CreateParsedType(T, TSI);
10176 /// Determine whether this failed name lookup should be treated as being
10177 /// disabled by a usage of std::enable_if.
10178 static bool isEnableIf(NestedNameSpecifierLoc NNS, const IdentifierInfo &II,
10179 SourceRange &CondRange, Expr *&Cond) {
10180 // We must be looking for a ::type...
10181 if (!II.isStr("type"))
10184 // ... within an explicitly-written template specialization...
10185 if (!NNS || !NNS.getNestedNameSpecifier()->getAsType())
10187 TypeLoc EnableIfTy = NNS.getTypeLoc();
10188 TemplateSpecializationTypeLoc EnableIfTSTLoc =
10189 EnableIfTy.getAs<TemplateSpecializationTypeLoc>();
10190 if (!EnableIfTSTLoc || EnableIfTSTLoc.getNumArgs() == 0)
10192 const TemplateSpecializationType *EnableIfTST = EnableIfTSTLoc.getTypePtr();
10194 // ... which names a complete class template declaration...
10195 const TemplateDecl *EnableIfDecl =
10196 EnableIfTST->getTemplateName().getAsTemplateDecl();
10197 if (!EnableIfDecl || EnableIfTST->isIncompleteType())
10200 // ... called "enable_if".
10201 const IdentifierInfo *EnableIfII =
10202 EnableIfDecl->getDeclName().getAsIdentifierInfo();
10203 if (!EnableIfII || !EnableIfII->isStr("enable_if"))
10206 // Assume the first template argument is the condition.
10207 CondRange = EnableIfTSTLoc.getArgLoc(0).getSourceRange();
10209 // Dig out the condition.
10211 if (EnableIfTSTLoc.getArgLoc(0).getArgument().getKind()
10212 != TemplateArgument::Expression)
10215 Cond = EnableIfTSTLoc.getArgLoc(0).getSourceExpression();
10217 // Ignore Boolean literals; they add no value.
10218 if (isa<CXXBoolLiteralExpr>(Cond->IgnoreParenCasts()))
10225 Sema::CheckTypenameType(ElaboratedTypeKeyword Keyword,
10226 SourceLocation KeywordLoc,
10227 NestedNameSpecifierLoc QualifierLoc,
10228 const IdentifierInfo &II,
10229 SourceLocation IILoc,
10230 TypeSourceInfo **TSI,
10231 bool DeducedTSTContext) {
10232 QualType T = CheckTypenameType(Keyword, KeywordLoc, QualifierLoc, II, IILoc,
10233 DeducedTSTContext);
10237 *TSI = Context.CreateTypeSourceInfo(T);
10238 if (isa<DependentNameType>(T)) {
10239 DependentNameTypeLoc TL =
10240 (*TSI)->getTypeLoc().castAs<DependentNameTypeLoc>();
10241 TL.setElaboratedKeywordLoc(KeywordLoc);
10242 TL.setQualifierLoc(QualifierLoc);
10243 TL.setNameLoc(IILoc);
10245 ElaboratedTypeLoc TL = (*TSI)->getTypeLoc().castAs<ElaboratedTypeLoc>();
10246 TL.setElaboratedKeywordLoc(KeywordLoc);
10247 TL.setQualifierLoc(QualifierLoc);
10248 TL.getNamedTypeLoc().castAs<TypeSpecTypeLoc>().setNameLoc(IILoc);
10253 /// Build the type that describes a C++ typename specifier,
10254 /// e.g., "typename T::type".
10256 Sema::CheckTypenameType(ElaboratedTypeKeyword Keyword,
10257 SourceLocation KeywordLoc,
10258 NestedNameSpecifierLoc QualifierLoc,
10259 const IdentifierInfo &II,
10260 SourceLocation IILoc, bool DeducedTSTContext) {
10262 SS.Adopt(QualifierLoc);
10264 DeclContext *Ctx = nullptr;
10265 if (QualifierLoc) {
10266 Ctx = computeDeclContext(SS);
10268 // If the nested-name-specifier is dependent and couldn't be
10269 // resolved to a type, build a typename type.
10270 assert(QualifierLoc.getNestedNameSpecifier()->isDependent());
10271 return Context.getDependentNameType(Keyword,
10272 QualifierLoc.getNestedNameSpecifier(),
10276 // If the nested-name-specifier refers to the current instantiation,
10277 // the "typename" keyword itself is superfluous. In C++03, the
10278 // program is actually ill-formed. However, DR 382 (in C++0x CD1)
10279 // allows such extraneous "typename" keywords, and we retroactively
10280 // apply this DR to C++03 code with only a warning. In any case we continue.
10282 if (RequireCompleteDeclContext(SS, Ctx))
10286 DeclarationName Name(&II);
10287 LookupResult Result(*this, Name, IILoc, LookupOrdinaryName);
10289 LookupQualifiedName(Result, Ctx, SS);
10291 LookupName(Result, CurScope);
10292 unsigned DiagID = 0;
10293 Decl *Referenced = nullptr;
10294 switch (Result.getResultKind()) {
10295 case LookupResult::NotFound: {
10296 // If we're looking up 'type' within a template named 'enable_if', produce
10297 // a more specific diagnostic.
10298 SourceRange CondRange;
10299 Expr *Cond = nullptr;
10300 if (Ctx && isEnableIf(QualifierLoc, II, CondRange, Cond)) {
10301 // If we have a condition, narrow it down to the specific failed
10305 std::string FailedDescription;
10306 std::tie(FailedCond, FailedDescription) =
10307 findFailedBooleanCondition(Cond);
10309 Diag(FailedCond->getExprLoc(),
10310 diag::err_typename_nested_not_found_requirement)
10311 << FailedDescription
10312 << FailedCond->getSourceRange();
10316 Diag(CondRange.getBegin(),
10317 diag::err_typename_nested_not_found_enable_if)
10318 << Ctx << CondRange;
10322 DiagID = Ctx ? diag::err_typename_nested_not_found
10323 : diag::err_unknown_typename;
10327 case LookupResult::FoundUnresolvedValue: {
10328 // We found a using declaration that is a value. Most likely, the using
10329 // declaration itself is meant to have the 'typename' keyword.
10330 SourceRange FullRange(KeywordLoc.isValid() ? KeywordLoc : SS.getBeginLoc(),
10332 Diag(IILoc, diag::err_typename_refers_to_using_value_decl)
10333 << Name << Ctx << FullRange;
10334 if (UnresolvedUsingValueDecl *Using
10335 = dyn_cast<UnresolvedUsingValueDecl>(Result.getRepresentativeDecl())){
10336 SourceLocation Loc = Using->getQualifierLoc().getBeginLoc();
10337 Diag(Loc, diag::note_using_value_decl_missing_typename)
10338 << FixItHint::CreateInsertion(Loc, "typename ");
10341 // Fall through to create a dependent typename type, from which we can recover
10345 case LookupResult::NotFoundInCurrentInstantiation:
10346 // Okay, it's a member of an unknown instantiation.
10347 return Context.getDependentNameType(Keyword,
10348 QualifierLoc.getNestedNameSpecifier(),
10351 case LookupResult::Found:
10352 if (TypeDecl *Type = dyn_cast<TypeDecl>(Result.getFoundDecl())) {
10353 // C++ [class.qual]p2:
10354 // In a lookup in which function names are not ignored and the
10355 // nested-name-specifier nominates a class C, if the name specified
10356 // after the nested-name-specifier, when looked up in C, is the
10357 // injected-class-name of C [...] then the name is instead considered
10358 // to name the constructor of class C.
10360 // Unlike in an elaborated-type-specifier, function names are not ignored
10361 // in typename-specifier lookup. However, they are ignored in all the
10362 // contexts where we form a typename type with no keyword (that is, in
10363 // mem-initializer-ids, base-specifiers, and elaborated-type-specifiers).
10365 // FIXME: That's not strictly true: mem-initializer-id lookup does not
10366 // ignore functions, but that appears to be an oversight.
10367 auto *LookupRD = dyn_cast_or_null<CXXRecordDecl>(Ctx);
10368 auto *FoundRD = dyn_cast<CXXRecordDecl>(Type);
10369 if (Keyword == ETK_Typename && LookupRD && FoundRD &&
10370 FoundRD->isInjectedClassName() &&
10371 declaresSameEntity(LookupRD, cast<Decl>(FoundRD->getParent())))
10372 Diag(IILoc, diag::ext_out_of_line_qualified_id_type_names_constructor)
10373 << &II << 1 << 0 /*'typename' keyword used*/;
10375 // We found a type. Build an ElaboratedType, since the
10376 // typename-specifier was just sugar.
10377 MarkAnyDeclReferenced(Type->getLocation(), Type, /*OdrUse=*/false);
10378 return Context.getElaboratedType(Keyword,
10379 QualifierLoc.getNestedNameSpecifier(),
10380 Context.getTypeDeclType(Type));
10383 // C++ [dcl.type.simple]p2:
10384 // A type-specifier of the form
10385 // typename[opt] nested-name-specifier[opt] template-name
10386 // is a placeholder for a deduced class type [...].
10387 if (getLangOpts().CPlusPlus17) {
10388 if (auto *TD = getAsTypeTemplateDecl(Result.getFoundDecl())) {
10389 if (!DeducedTSTContext) {
10390 QualType T(QualifierLoc
10391 ? QualifierLoc.getNestedNameSpecifier()->getAsType()
10394 Diag(IILoc, diag::err_dependent_deduced_tst)
10395 << (int)getTemplateNameKindForDiagnostics(TemplateName(TD)) << T;
10397 Diag(IILoc, diag::err_deduced_tst)
10398 << (int)getTemplateNameKindForDiagnostics(TemplateName(TD));
10399 Diag(TD->getLocation(), diag::note_template_decl_here);
10402 return Context.getElaboratedType(
10403 Keyword, QualifierLoc.getNestedNameSpecifier(),
10404 Context.getDeducedTemplateSpecializationType(TemplateName(TD),
10405 QualType(), false));
10409 DiagID = Ctx ? diag::err_typename_nested_not_type
10410 : diag::err_typename_not_type;
10411 Referenced = Result.getFoundDecl();
10414 case LookupResult::FoundOverloaded:
10415 DiagID = Ctx ? diag::err_typename_nested_not_type
10416 : diag::err_typename_not_type;
10417 Referenced = *Result.begin();
10420 case LookupResult::Ambiguous:
10424 // If we get here, it's because name lookup did not find a
10425 // type. Emit an appropriate diagnostic and return an error.
10426 SourceRange FullRange(KeywordLoc.isValid() ? KeywordLoc : SS.getBeginLoc(),
10429 Diag(IILoc, DiagID) << FullRange << Name << Ctx;
10431 Diag(IILoc, DiagID) << FullRange << Name;
10433 Diag(Referenced->getLocation(),
10434 Ctx ? diag::note_typename_member_refers_here
10435 : diag::note_typename_refers_here)
10441 // See Sema::RebuildTypeInCurrentInstantiation
10442 class CurrentInstantiationRebuilder
10443 : public TreeTransform<CurrentInstantiationRebuilder> {
10444 SourceLocation Loc;
10445 DeclarationName Entity;
10448 typedef TreeTransform<CurrentInstantiationRebuilder> inherited;
10450 CurrentInstantiationRebuilder(Sema &SemaRef,
10451 SourceLocation Loc,
10452 DeclarationName Entity)
10453 : TreeTransform<CurrentInstantiationRebuilder>(SemaRef),
10454 Loc(Loc), Entity(Entity) { }
10456 /// Determine whether the given type \p T has already been
10459 /// For the purposes of type reconstruction, a type has already been
10460 /// transformed if it is NULL or if it is not dependent.
10461 bool AlreadyTransformed(QualType T) {
10462 return T.isNull() || !T->isDependentType();
10465 /// Returns the location of the entity whose type is being
10467 SourceLocation getBaseLocation() { return Loc; }
10469 /// Returns the name of the entity whose type is being rebuilt.
10470 DeclarationName getBaseEntity() { return Entity; }
10472 /// Sets the "base" location and entity when that
10473 /// information is known based on another transformation.
10474 void setBase(SourceLocation Loc, DeclarationName Entity) {
10476 this->Entity = Entity;
10479 ExprResult TransformLambdaExpr(LambdaExpr *E) {
10480 // Lambdas never need to be transformed.
10484 } // end anonymous namespace
10486 /// Rebuilds a type within the context of the current instantiation.
10488 /// The type \p T is part of the type of an out-of-line member definition of
10489 /// a class template (or class template partial specialization) that was parsed
10490 /// and constructed before we entered the scope of the class template (or
10491 /// partial specialization thereof). This routine will rebuild that type now
10492 /// that we have entered the declarator's scope, which may produce different
10493 /// canonical types, e.g.,
10496 /// template<typename T>
10498 /// typedef T* pointer;
10499 /// pointer data();
10502 /// template<typename T>
10503 /// typename X<T>::pointer X<T>::data() { ... }
10506 /// Here, the type "typename X<T>::pointer" will be created as a DependentNameType,
10507 /// since we do not know that we can look into X<T> when we parsed the type.
10508 /// This function will rebuild the type, performing the lookup of "pointer"
10509 /// in X<T> and returning an ElaboratedType whose canonical type is the same
10510 /// as the canonical type of T*, allowing the return types of the out-of-line
10511 /// definition and the declaration to match.
10512 TypeSourceInfo *Sema::RebuildTypeInCurrentInstantiation(TypeSourceInfo *T,
10513 SourceLocation Loc,
10514 DeclarationName Name) {
10515 if (!T || !T->getType()->isDependentType())
10518 CurrentInstantiationRebuilder Rebuilder(*this, Loc, Name);
10519 return Rebuilder.TransformType(T);
10522 ExprResult Sema::RebuildExprInCurrentInstantiation(Expr *E) {
10523 CurrentInstantiationRebuilder Rebuilder(*this, E->getExprLoc(),
10524 DeclarationName());
10525 return Rebuilder.TransformExpr(E);
10528 bool Sema::RebuildNestedNameSpecifierInCurrentInstantiation(CXXScopeSpec &SS) {
10529 if (SS.isInvalid())
10532 NestedNameSpecifierLoc QualifierLoc = SS.getWithLocInContext(Context);
10533 CurrentInstantiationRebuilder Rebuilder(*this, SS.getRange().getBegin(),
10534 DeclarationName());
10535 NestedNameSpecifierLoc Rebuilt
10536 = Rebuilder.TransformNestedNameSpecifierLoc(QualifierLoc);
10544 /// Rebuild the template parameters now that we know we're in a current
10546 bool Sema::RebuildTemplateParamsInCurrentInstantiation(
10547 TemplateParameterList *Params) {
10548 for (unsigned I = 0, N = Params->size(); I != N; ++I) {
10549 Decl *Param = Params->getParam(I);
10551 // There is nothing to rebuild in a type parameter.
10552 if (isa<TemplateTypeParmDecl>(Param))
10555 // Rebuild the template parameter list of a template template parameter.
10556 if (TemplateTemplateParmDecl *TTP
10557 = dyn_cast<TemplateTemplateParmDecl>(Param)) {
10558 if (RebuildTemplateParamsInCurrentInstantiation(
10559 TTP->getTemplateParameters()))
10565 // Rebuild the type of a non-type template parameter.
10566 NonTypeTemplateParmDecl *NTTP = cast<NonTypeTemplateParmDecl>(Param);
10567 TypeSourceInfo *NewTSI
10568 = RebuildTypeInCurrentInstantiation(NTTP->getTypeSourceInfo(),
10569 NTTP->getLocation(),
10570 NTTP->getDeclName());
10574 if (NewTSI->getType()->isUndeducedType()) {
10575 // C++17 [temp.dep.expr]p3:
10576 // An id-expression is type-dependent if it contains
10577 // - an identifier associated by name lookup with a non-type
10578 // template-parameter declared with a type that contains a
10579 // placeholder type (7.1.7.4),
10580 NewTSI = SubstAutoTypeSourceInfo(NewTSI, Context.DependentTy);
10583 if (NewTSI != NTTP->getTypeSourceInfo()) {
10584 NTTP->setTypeSourceInfo(NewTSI);
10585 NTTP->setType(NewTSI->getType());
10592 /// Produces a formatted string that describes the binding of
10593 /// template parameters to template arguments.
10595 Sema::getTemplateArgumentBindingsText(const TemplateParameterList *Params,
10596 const TemplateArgumentList &Args) {
10597 return getTemplateArgumentBindingsText(Params, Args.data(), Args.size());
10601 Sema::getTemplateArgumentBindingsText(const TemplateParameterList *Params,
10602 const TemplateArgument *Args,
10603 unsigned NumArgs) {
10604 SmallString<128> Str;
10605 llvm::raw_svector_ostream Out(Str);
10607 if (!Params || Params->size() == 0 || NumArgs == 0)
10608 return std::string();
10610 for (unsigned I = 0, N = Params->size(); I != N; ++I) {
10619 if (const IdentifierInfo *Id = Params->getParam(I)->getIdentifier()) {
10620 Out << Id->getName();
10626 Args[I].print(getPrintingPolicy(), Out);
10633 void Sema::MarkAsLateParsedTemplate(FunctionDecl *FD, Decl *FnD,
10634 CachedTokens &Toks) {
10638 auto LPT = std::make_unique<LateParsedTemplate>();
10640 // Take tokens to avoid allocations
10641 LPT->Toks.swap(Toks);
10643 LateParsedTemplateMap.insert(std::make_pair(FD, std::move(LPT)));
10645 FD->setLateTemplateParsed(true);
10648 void Sema::UnmarkAsLateParsedTemplate(FunctionDecl *FD) {
10651 FD->setLateTemplateParsed(false);
10654 bool Sema::IsInsideALocalClassWithinATemplateFunction() {
10655 DeclContext *DC = CurContext;
10658 if (CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(CurContext)) {
10659 const FunctionDecl *FD = RD->isLocalClass();
10660 return (FD && FD->getTemplatedKind() != FunctionDecl::TK_NonTemplate);
10661 } else if (DC->isTranslationUnit() || DC->isNamespace())
10664 DC = DC->getParent();
10670 /// Walk the path from which a declaration was instantiated, and check
10671 /// that every explicit specialization along that path is visible. This enforces
10672 /// C++ [temp.expl.spec]/6:
10674 /// If a template, a member template or a member of a class template is
10675 /// explicitly specialized then that specialization shall be declared before
10676 /// the first use of that specialization that would cause an implicit
10677 /// instantiation to take place, in every translation unit in which such a
10678 /// use occurs; no diagnostic is required.
10680 /// and also C++ [temp.class.spec]/1:
10682 /// A partial specialization shall be declared before the first use of a
10683 /// class template specialization that would make use of the partial
10684 /// specialization as the result of an implicit or explicit instantiation
10685 /// in every translation unit in which such a use occurs; no diagnostic is
10687 class ExplicitSpecializationVisibilityChecker {
10689 SourceLocation Loc;
10690 llvm::SmallVector<Module *, 8> Modules;
10693 ExplicitSpecializationVisibilityChecker(Sema &S, SourceLocation Loc)
10694 : S(S), Loc(Loc) {}
10696 void check(NamedDecl *ND) {
10697 if (auto *FD = dyn_cast<FunctionDecl>(ND))
10698 return checkImpl(FD);
10699 if (auto *RD = dyn_cast<CXXRecordDecl>(ND))
10700 return checkImpl(RD);
10701 if (auto *VD = dyn_cast<VarDecl>(ND))
10702 return checkImpl(VD);
10703 if (auto *ED = dyn_cast<EnumDecl>(ND))
10704 return checkImpl(ED);
10708 void diagnose(NamedDecl *D, bool IsPartialSpec) {
10709 auto Kind = IsPartialSpec ? Sema::MissingImportKind::PartialSpecialization
10710 : Sema::MissingImportKind::ExplicitSpecialization;
10711 const bool Recover = true;
10713 // If we got a custom set of modules (because only a subset of the
10714 // declarations are interesting), use them, otherwise let
10715 // diagnoseMissingImport intelligently pick some.
10716 if (Modules.empty())
10717 S.diagnoseMissingImport(Loc, D, Kind, Recover);
10719 S.diagnoseMissingImport(Loc, D, D->getLocation(), Modules, Kind, Recover);
10722 // Check a specific declaration. There are three problematic cases:
10724 // 1) The declaration is an explicit specialization of a template
10726 // 2) The declaration is an explicit specialization of a member of an
10727 // templated class.
10728 // 3) The declaration is an instantiation of a template, and that template
10729 // is an explicit specialization of a member of a templated class.
10731 // We don't need to go any deeper than that, as the instantiation of the
10732 // surrounding class / etc is not triggered by whatever triggered this
10733 // instantiation, and thus should be checked elsewhere.
10734 template<typename SpecDecl>
10735 void checkImpl(SpecDecl *Spec) {
10736 bool IsHiddenExplicitSpecialization = false;
10737 if (Spec->getTemplateSpecializationKind() == TSK_ExplicitSpecialization) {
10738 IsHiddenExplicitSpecialization =
10739 Spec->getMemberSpecializationInfo()
10740 ? !S.hasVisibleMemberSpecialization(Spec, &Modules)
10741 : !S.hasVisibleExplicitSpecialization(Spec, &Modules);
10743 checkInstantiated(Spec);
10746 if (IsHiddenExplicitSpecialization)
10747 diagnose(Spec->getMostRecentDecl(), false);
10750 void checkInstantiated(FunctionDecl *FD) {
10751 if (auto *TD = FD->getPrimaryTemplate())
10755 void checkInstantiated(CXXRecordDecl *RD) {
10756 auto *SD = dyn_cast<ClassTemplateSpecializationDecl>(RD);
10760 auto From = SD->getSpecializedTemplateOrPartial();
10761 if (auto *TD = From.dyn_cast<ClassTemplateDecl *>())
10763 else if (auto *TD =
10764 From.dyn_cast<ClassTemplatePartialSpecializationDecl *>()) {
10765 if (!S.hasVisibleDeclaration(TD))
10766 diagnose(TD, true);
10771 void checkInstantiated(VarDecl *RD) {
10772 auto *SD = dyn_cast<VarTemplateSpecializationDecl>(RD);
10776 auto From = SD->getSpecializedTemplateOrPartial();
10777 if (auto *TD = From.dyn_cast<VarTemplateDecl *>())
10779 else if (auto *TD =
10780 From.dyn_cast<VarTemplatePartialSpecializationDecl *>()) {
10781 if (!S.hasVisibleDeclaration(TD))
10782 diagnose(TD, true);
10787 void checkInstantiated(EnumDecl *FD) {}
10789 template<typename TemplDecl>
10790 void checkTemplate(TemplDecl *TD) {
10791 if (TD->isMemberSpecialization()) {
10792 if (!S.hasVisibleMemberSpecialization(TD, &Modules))
10793 diagnose(TD->getMostRecentDecl(), false);
10797 } // end anonymous namespace
10799 void Sema::checkSpecializationVisibility(SourceLocation Loc, NamedDecl *Spec) {
10800 if (!getLangOpts().Modules)
10803 ExplicitSpecializationVisibilityChecker(*this, Loc).check(Spec);
10806 /// Check whether a template partial specialization that we've discovered
10807 /// is hidden, and produce suitable diagnostics if so.
10808 void Sema::checkPartialSpecializationVisibility(SourceLocation Loc,
10810 llvm::SmallVector<Module *, 8> Modules;
10811 if (!hasVisibleDeclaration(Spec, &Modules))
10812 diagnoseMissingImport(Loc, Spec, Spec->getLocation(), Modules,
10813 MissingImportKind::PartialSpecialization,