1 //===------- SemaTemplate.cpp - Semantic Analysis for C++ Templates -------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //===----------------------------------------------------------------------===//
9 // This file implements semantic analysis for C++ templates.
10 //===----------------------------------------------------------------------===//
12 #include "TreeTransform.h"
13 #include "clang/AST/ASTConsumer.h"
14 #include "clang/AST/ASTContext.h"
15 #include "clang/AST/DeclFriend.h"
16 #include "clang/AST/DeclTemplate.h"
17 #include "clang/AST/Expr.h"
18 #include "clang/AST/ExprCXX.h"
19 #include "clang/AST/RecursiveASTVisitor.h"
20 #include "clang/AST/TypeVisitor.h"
21 #include "clang/Basic/Builtins.h"
22 #include "clang/Basic/LangOptions.h"
23 #include "clang/Basic/PartialDiagnostic.h"
24 #include "clang/Basic/TargetInfo.h"
25 #include "clang/Sema/DeclSpec.h"
26 #include "clang/Sema/Lookup.h"
27 #include "clang/Sema/ParsedTemplate.h"
28 #include "clang/Sema/Scope.h"
29 #include "clang/Sema/SemaInternal.h"
30 #include "clang/Sema/Template.h"
31 #include "clang/Sema/TemplateDeduction.h"
32 #include "llvm/ADT/SmallBitVector.h"
33 #include "llvm/ADT/SmallString.h"
34 #include "llvm/ADT/StringExtras.h"
37 using namespace clang;
40 // Exported for use by Parser.
42 clang::getTemplateParamsRange(TemplateParameterList const * const *Ps,
44 if (!N) return SourceRange();
45 return SourceRange(Ps[0]->getTemplateLoc(), Ps[N-1]->getRAngleLoc());
49 /// [temp.constr.decl]p2: A template's associated constraints are
50 /// defined as a single constraint-expression derived from the introduced
51 /// constraint-expressions [ ... ].
53 /// \param Params The template parameter list and optional requires-clause.
55 /// \param FD The underlying templated function declaration for a function
57 static Expr *formAssociatedConstraints(TemplateParameterList *Params,
61 static Expr *clang::formAssociatedConstraints(TemplateParameterList *Params,
63 // FIXME: Concepts: collect additional introduced constraint-expressions
64 assert(!FD && "Cannot collect constraints from function declaration yet.");
65 return Params->getRequiresClause();
68 /// Determine whether the declaration found is acceptable as the name
69 /// of a template and, if so, return that template declaration. Otherwise,
71 static NamedDecl *isAcceptableTemplateName(ASTContext &Context,
73 bool AllowFunctionTemplates) {
74 NamedDecl *D = Orig->getUnderlyingDecl();
76 if (isa<TemplateDecl>(D)) {
77 if (!AllowFunctionTemplates && isa<FunctionTemplateDecl>(D))
83 if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(D)) {
84 // C++ [temp.local]p1:
85 // Like normal (non-template) classes, class templates have an
86 // injected-class-name (Clause 9). The injected-class-name
87 // can be used with or without a template-argument-list. When
88 // it is used without a template-argument-list, it is
89 // equivalent to the injected-class-name followed by the
90 // template-parameters of the class template enclosed in
91 // <>. When it is used with a template-argument-list, it
92 // refers to the specified class template specialization,
93 // which could be the current specialization or another
95 if (Record->isInjectedClassName()) {
96 Record = cast<CXXRecordDecl>(Record->getDeclContext());
97 if (Record->getDescribedClassTemplate())
98 return Record->getDescribedClassTemplate();
100 if (ClassTemplateSpecializationDecl *Spec
101 = dyn_cast<ClassTemplateSpecializationDecl>(Record))
102 return Spec->getSpecializedTemplate();
108 // 'using Dependent::foo;' can resolve to a template name.
109 // 'using typename Dependent::foo;' cannot (not even if 'foo' is an
110 // injected-class-name).
111 if (isa<UnresolvedUsingValueDecl>(D))
117 void Sema::FilterAcceptableTemplateNames(LookupResult &R,
118 bool AllowFunctionTemplates) {
119 // The set of class templates we've already seen.
120 llvm::SmallPtrSet<ClassTemplateDecl *, 8> ClassTemplates;
121 LookupResult::Filter filter = R.makeFilter();
122 while (filter.hasNext()) {
123 NamedDecl *Orig = filter.next();
124 NamedDecl *Repl = isAcceptableTemplateName(Context, Orig,
125 AllowFunctionTemplates);
128 else if (Repl != Orig) {
130 // C++ [temp.local]p3:
131 // A lookup that finds an injected-class-name (10.2) can result in an
132 // ambiguity in certain cases (for example, if it is found in more than
133 // one base class). If all of the injected-class-names that are found
134 // refer to specializations of the same class template, and if the name
135 // is used as a template-name, the reference refers to the class
136 // template itself and not a specialization thereof, and is not
138 if (ClassTemplateDecl *ClassTmpl = dyn_cast<ClassTemplateDecl>(Repl))
139 if (!ClassTemplates.insert(ClassTmpl).second) {
144 // FIXME: we promote access to public here as a workaround to
145 // the fact that LookupResult doesn't let us remember that we
146 // found this template through a particular injected class name,
147 // which means we end up doing nasty things to the invariants.
148 // Pretending that access is public is *much* safer.
149 filter.replace(Repl, AS_public);
155 bool Sema::hasAnyAcceptableTemplateNames(LookupResult &R,
156 bool AllowFunctionTemplates) {
157 for (LookupResult::iterator I = R.begin(), IEnd = R.end(); I != IEnd; ++I)
158 if (isAcceptableTemplateName(Context, *I, AllowFunctionTemplates))
164 TemplateNameKind Sema::isTemplateName(Scope *S,
166 bool hasTemplateKeyword,
167 const UnqualifiedId &Name,
168 ParsedType ObjectTypePtr,
169 bool EnteringContext,
170 TemplateTy &TemplateResult,
171 bool &MemberOfUnknownSpecialization) {
172 assert(getLangOpts().CPlusPlus && "No template names in C!");
174 DeclarationName TName;
175 MemberOfUnknownSpecialization = false;
177 switch (Name.getKind()) {
178 case UnqualifiedIdKind::IK_Identifier:
179 TName = DeclarationName(Name.Identifier);
182 case UnqualifiedIdKind::IK_OperatorFunctionId:
183 TName = Context.DeclarationNames.getCXXOperatorName(
184 Name.OperatorFunctionId.Operator);
187 case UnqualifiedIdKind::IK_LiteralOperatorId:
188 TName = Context.DeclarationNames.getCXXLiteralOperatorName(Name.Identifier);
192 return TNK_Non_template;
195 QualType ObjectType = ObjectTypePtr.get();
197 LookupResult R(*this, TName, Name.getBeginLoc(), LookupOrdinaryName);
198 if (LookupTemplateName(R, S, SS, ObjectType, EnteringContext,
199 MemberOfUnknownSpecialization))
200 return TNK_Non_template;
201 if (R.empty()) return TNK_Non_template;
202 if (R.isAmbiguous()) {
203 // Suppress diagnostics; we'll redo this lookup later.
204 R.suppressDiagnostics();
206 // FIXME: we might have ambiguous templates, in which case we
207 // should at least parse them properly!
208 return TNK_Non_template;
211 TemplateName Template;
212 TemplateNameKind TemplateKind;
214 unsigned ResultCount = R.end() - R.begin();
215 if (ResultCount > 1) {
216 // We assume that we'll preserve the qualifier from a function
217 // template name in other ways.
218 Template = Context.getOverloadedTemplateName(R.begin(), R.end());
219 TemplateKind = TNK_Function_template;
221 // We'll do this lookup again later.
222 R.suppressDiagnostics();
223 } else if (isa<UnresolvedUsingValueDecl>((*R.begin())->getUnderlyingDecl())) {
224 // We don't yet know whether this is a template-name or not.
225 MemberOfUnknownSpecialization = true;
226 return TNK_Non_template;
228 TemplateDecl *TD = cast<TemplateDecl>((*R.begin())->getUnderlyingDecl());
230 if (SS.isSet() && !SS.isInvalid()) {
231 NestedNameSpecifier *Qualifier = SS.getScopeRep();
232 Template = Context.getQualifiedTemplateName(Qualifier,
233 hasTemplateKeyword, TD);
235 Template = TemplateName(TD);
238 if (isa<FunctionTemplateDecl>(TD)) {
239 TemplateKind = TNK_Function_template;
241 // We'll do this lookup again later.
242 R.suppressDiagnostics();
244 assert(isa<ClassTemplateDecl>(TD) || isa<TemplateTemplateParmDecl>(TD) ||
245 isa<TypeAliasTemplateDecl>(TD) || isa<VarTemplateDecl>(TD) ||
246 isa<BuiltinTemplateDecl>(TD));
248 isa<VarTemplateDecl>(TD) ? TNK_Var_template : TNK_Type_template;
252 TemplateResult = TemplateTy::make(Template);
256 bool Sema::isDeductionGuideName(Scope *S, const IdentifierInfo &Name,
257 SourceLocation NameLoc,
258 ParsedTemplateTy *Template) {
260 bool MemberOfUnknownSpecialization = false;
262 // We could use redeclaration lookup here, but we don't need to: the
263 // syntactic form of a deduction guide is enough to identify it even
264 // if we can't look up the template name at all.
265 LookupResult R(*this, DeclarationName(&Name), NameLoc, LookupOrdinaryName);
266 if (LookupTemplateName(R, S, SS, /*ObjectType*/ QualType(),
267 /*EnteringContext*/ false,
268 MemberOfUnknownSpecialization))
271 if (R.empty()) return false;
272 if (R.isAmbiguous()) {
273 // FIXME: Diagnose an ambiguity if we find at least one template.
274 R.suppressDiagnostics();
278 // We only treat template-names that name type templates as valid deduction
280 TemplateDecl *TD = R.getAsSingle<TemplateDecl>();
281 if (!TD || !getAsTypeTemplateDecl(TD))
285 *Template = TemplateTy::make(TemplateName(TD));
289 bool Sema::DiagnoseUnknownTemplateName(const IdentifierInfo &II,
290 SourceLocation IILoc,
292 const CXXScopeSpec *SS,
293 TemplateTy &SuggestedTemplate,
294 TemplateNameKind &SuggestedKind) {
295 // We can't recover unless there's a dependent scope specifier preceding the
297 // FIXME: Typo correction?
298 if (!SS || !SS->isSet() || !isDependentScopeSpecifier(*SS) ||
299 computeDeclContext(*SS))
302 // The code is missing a 'template' keyword prior to the dependent template
304 NestedNameSpecifier *Qualifier = (NestedNameSpecifier*)SS->getScopeRep();
305 Diag(IILoc, diag::err_template_kw_missing)
306 << Qualifier << II.getName()
307 << FixItHint::CreateInsertion(IILoc, "template ");
309 = TemplateTy::make(Context.getDependentTemplateName(Qualifier, &II));
310 SuggestedKind = TNK_Dependent_template_name;
314 bool Sema::LookupTemplateName(LookupResult &Found,
315 Scope *S, CXXScopeSpec &SS,
317 bool EnteringContext,
318 bool &MemberOfUnknownSpecialization,
319 SourceLocation TemplateKWLoc) {
320 // Determine where to perform name lookup
321 MemberOfUnknownSpecialization = false;
322 DeclContext *LookupCtx = nullptr;
323 bool IsDependent = false;
324 if (!ObjectType.isNull()) {
325 // This nested-name-specifier occurs in a member access expression, e.g.,
326 // x->B::f, and we are looking into the type of the object.
327 assert(!SS.isSet() && "ObjectType and scope specifier cannot coexist");
328 LookupCtx = computeDeclContext(ObjectType);
329 IsDependent = !LookupCtx;
330 assert((IsDependent || !ObjectType->isIncompleteType() ||
331 ObjectType->castAs<TagType>()->isBeingDefined()) &&
332 "Caller should have completed object type");
334 // Template names cannot appear inside an Objective-C class or object type.
335 if (ObjectType->isObjCObjectOrInterfaceType()) {
339 } else if (SS.isSet()) {
340 // This nested-name-specifier occurs after another nested-name-specifier,
341 // so long into the context associated with the prior nested-name-specifier.
342 LookupCtx = computeDeclContext(SS, EnteringContext);
343 IsDependent = !LookupCtx;
345 // The declaration context must be complete.
346 if (LookupCtx && RequireCompleteDeclContext(SS, LookupCtx))
350 bool ObjectTypeSearchedInScope = false;
351 bool AllowFunctionTemplatesInLookup = true;
353 // Perform "qualified" name lookup into the declaration context we
354 // computed, which is either the type of the base of a member access
355 // expression or the declaration context associated with a prior
356 // nested-name-specifier.
357 LookupQualifiedName(Found, LookupCtx);
359 // FIXME: The C++ standard does not clearly specify what happens in the
360 // case where the object type is dependent, and implementations vary. In
361 // Clang, we treat a name after a . or -> as a template-name if lookup
362 // finds a non-dependent member or member of the current instantiation that
363 // is a type template, or finds no such members and lookup in the context
364 // of the postfix-expression finds a type template. In the latter case, the
365 // name is nonetheless dependent, and we may resolve it to a member of an
366 // unknown specialization when we come to instantiate the template.
367 IsDependent |= Found.wasNotFoundInCurrentInstantiation();
370 if (!SS.isSet() && (ObjectType.isNull() || Found.empty())) {
371 // C++ [basic.lookup.classref]p1:
372 // In a class member access expression (5.2.5), if the . or -> token is
373 // immediately followed by an identifier followed by a <, the
374 // identifier must be looked up to determine whether the < is the
375 // beginning of a template argument list (14.2) or a less-than operator.
376 // The identifier is first looked up in the class of the object
377 // expression. If the identifier is not found, it is then looked up in
378 // the context of the entire postfix-expression and shall name a class
381 LookupName(Found, S);
383 if (!ObjectType.isNull()) {
384 // FIXME: We should filter out all non-type templates here, particularly
385 // variable templates and concepts. But the exclusion of alias templates
386 // and template template parameters is a wording defect.
387 AllowFunctionTemplatesInLookup = false;
388 ObjectTypeSearchedInScope = true;
391 IsDependent |= Found.wasNotFoundInCurrentInstantiation();
394 if (Found.empty() && !IsDependent) {
395 // If we did not find any names, attempt to correct any typos.
396 DeclarationName Name = Found.getLookupName();
398 // Simple filter callback that, for keywords, only accepts the C++ *_cast
399 auto FilterCCC = llvm::make_unique<CorrectionCandidateCallback>();
400 FilterCCC->WantTypeSpecifiers = false;
401 FilterCCC->WantExpressionKeywords = false;
402 FilterCCC->WantRemainingKeywords = false;
403 FilterCCC->WantCXXNamedCasts = true;
404 if (TypoCorrection Corrected = CorrectTypo(
405 Found.getLookupNameInfo(), Found.getLookupKind(), S, &SS,
406 std::move(FilterCCC), CTK_ErrorRecovery, LookupCtx)) {
407 Found.setLookupName(Corrected.getCorrection());
408 if (auto *ND = Corrected.getFoundDecl())
410 FilterAcceptableTemplateNames(Found);
411 if (!Found.empty()) {
413 std::string CorrectedStr(Corrected.getAsString(getLangOpts()));
414 bool DroppedSpecifier = Corrected.WillReplaceSpecifier() &&
415 Name.getAsString() == CorrectedStr;
416 diagnoseTypo(Corrected, PDiag(diag::err_no_member_template_suggest)
417 << Name << LookupCtx << DroppedSpecifier
420 diagnoseTypo(Corrected, PDiag(diag::err_no_template_suggest) << Name);
424 Found.setLookupName(Name);
428 NamedDecl *ExampleLookupResult =
429 Found.empty() ? nullptr : Found.getRepresentativeDecl();
430 FilterAcceptableTemplateNames(Found, AllowFunctionTemplatesInLookup);
433 MemberOfUnknownSpecialization = true;
437 // If a 'template' keyword was used, a lookup that finds only non-template
438 // names is an error.
439 if (ExampleLookupResult && TemplateKWLoc.isValid()) {
440 Diag(Found.getNameLoc(), diag::err_template_kw_refers_to_non_template)
441 << Found.getLookupName() << SS.getRange();
442 Diag(ExampleLookupResult->getUnderlyingDecl()->getLocation(),
443 diag::note_template_kw_refers_to_non_template)
444 << Found.getLookupName();
451 if (S && !ObjectType.isNull() && !ObjectTypeSearchedInScope &&
452 !getLangOpts().CPlusPlus11) {
453 // C++03 [basic.lookup.classref]p1:
454 // [...] If the lookup in the class of the object expression finds a
455 // template, the name is also looked up in the context of the entire
456 // postfix-expression and [...]
458 // Note: C++11 does not perform this second lookup.
459 LookupResult FoundOuter(*this, Found.getLookupName(), Found.getNameLoc(),
461 LookupName(FoundOuter, S);
462 FilterAcceptableTemplateNames(FoundOuter, /*AllowFunctionTemplates=*/false);
464 if (FoundOuter.empty()) {
465 // - if the name is not found, the name found in the class of the
466 // object expression is used, otherwise
467 } else if (!FoundOuter.getAsSingle<ClassTemplateDecl>() ||
468 FoundOuter.isAmbiguous()) {
469 // - if the name is found in the context of the entire
470 // postfix-expression and does not name a class template, the name
471 // found in the class of the object expression is used, otherwise
473 } else if (!Found.isSuppressingDiagnostics()) {
474 // - if the name found is a class template, it must refer to the same
475 // entity as the one found in the class of the object expression,
476 // otherwise the program is ill-formed.
477 if (!Found.isSingleResult() ||
478 Found.getFoundDecl()->getCanonicalDecl()
479 != FoundOuter.getFoundDecl()->getCanonicalDecl()) {
480 Diag(Found.getNameLoc(),
481 diag::ext_nested_name_member_ref_lookup_ambiguous)
482 << Found.getLookupName()
484 Diag(Found.getRepresentativeDecl()->getLocation(),
485 diag::note_ambig_member_ref_object_type)
487 Diag(FoundOuter.getFoundDecl()->getLocation(),
488 diag::note_ambig_member_ref_scope);
490 // Recover by taking the template that we found in the object
491 // expression's type.
499 void Sema::diagnoseExprIntendedAsTemplateName(Scope *S, ExprResult TemplateName,
501 SourceLocation Greater) {
502 if (TemplateName.isInvalid())
505 DeclarationNameInfo NameInfo;
507 LookupNameKind LookupKind;
509 DeclContext *LookupCtx = nullptr;
510 NamedDecl *Found = nullptr;
511 bool MissingTemplateKeyword = false;
513 // Figure out what name we looked up.
514 if (auto *DRE = dyn_cast<DeclRefExpr>(TemplateName.get())) {
515 NameInfo = DRE->getNameInfo();
516 SS.Adopt(DRE->getQualifierLoc());
517 LookupKind = LookupOrdinaryName;
518 Found = DRE->getFoundDecl();
519 } else if (auto *ME = dyn_cast<MemberExpr>(TemplateName.get())) {
520 NameInfo = ME->getMemberNameInfo();
521 SS.Adopt(ME->getQualifierLoc());
522 LookupKind = LookupMemberName;
523 LookupCtx = ME->getBase()->getType()->getAsCXXRecordDecl();
524 Found = ME->getMemberDecl();
525 } else if (auto *DSDRE =
526 dyn_cast<DependentScopeDeclRefExpr>(TemplateName.get())) {
527 NameInfo = DSDRE->getNameInfo();
528 SS.Adopt(DSDRE->getQualifierLoc());
529 MissingTemplateKeyword = true;
530 } else if (auto *DSME =
531 dyn_cast<CXXDependentScopeMemberExpr>(TemplateName.get())) {
532 NameInfo = DSME->getMemberNameInfo();
533 SS.Adopt(DSME->getQualifierLoc());
534 MissingTemplateKeyword = true;
536 llvm_unreachable("unexpected kind of potential template name");
539 // If this is a dependent-scope lookup, diagnose that the 'template' keyword
541 if (MissingTemplateKeyword) {
542 Diag(NameInfo.getBeginLoc(), diag::err_template_kw_missing)
543 << "" << NameInfo.getName().getAsString() << SourceRange(Less, Greater);
547 // Try to correct the name by looking for templates and C++ named casts.
548 struct TemplateCandidateFilter : CorrectionCandidateCallback {
549 TemplateCandidateFilter() {
550 WantTypeSpecifiers = false;
551 WantExpressionKeywords = false;
552 WantRemainingKeywords = false;
553 WantCXXNamedCasts = true;
555 bool ValidateCandidate(const TypoCorrection &Candidate) override {
556 if (auto *ND = Candidate.getCorrectionDecl())
557 return isAcceptableTemplateName(ND->getASTContext(), ND, true);
558 return Candidate.isKeyword();
562 DeclarationName Name = NameInfo.getName();
563 if (TypoCorrection Corrected =
564 CorrectTypo(NameInfo, LookupKind, S, &SS,
565 llvm::make_unique<TemplateCandidateFilter>(),
566 CTK_ErrorRecovery, LookupCtx)) {
567 auto *ND = Corrected.getFoundDecl();
569 ND = isAcceptableTemplateName(Context, ND,
570 /*AllowFunctionTemplates*/ true);
571 if (ND || Corrected.isKeyword()) {
573 std::string CorrectedStr(Corrected.getAsString(getLangOpts()));
574 bool DroppedSpecifier = Corrected.WillReplaceSpecifier() &&
575 Name.getAsString() == CorrectedStr;
576 diagnoseTypo(Corrected,
577 PDiag(diag::err_non_template_in_member_template_id_suggest)
578 << Name << LookupCtx << DroppedSpecifier
579 << SS.getRange(), false);
581 diagnoseTypo(Corrected,
582 PDiag(diag::err_non_template_in_template_id_suggest)
586 Diag(Found->getLocation(),
587 diag::note_non_template_in_template_id_found);
592 Diag(NameInfo.getLoc(), diag::err_non_template_in_template_id)
593 << Name << SourceRange(Less, Greater);
595 Diag(Found->getLocation(), diag::note_non_template_in_template_id_found);
598 /// ActOnDependentIdExpression - Handle a dependent id-expression that
599 /// was just parsed. This is only possible with an explicit scope
600 /// specifier naming a dependent type.
602 Sema::ActOnDependentIdExpression(const CXXScopeSpec &SS,
603 SourceLocation TemplateKWLoc,
604 const DeclarationNameInfo &NameInfo,
605 bool isAddressOfOperand,
606 const TemplateArgumentListInfo *TemplateArgs) {
607 DeclContext *DC = getFunctionLevelDeclContext();
609 // C++11 [expr.prim.general]p12:
610 // An id-expression that denotes a non-static data member or non-static
611 // member function of a class can only be used:
613 // - if that id-expression denotes a non-static data member and it
614 // appears in an unevaluated operand.
616 // If this might be the case, form a DependentScopeDeclRefExpr instead of a
617 // CXXDependentScopeMemberExpr. The former can instantiate to either
618 // DeclRefExpr or MemberExpr depending on lookup results, while the latter is
619 // always a MemberExpr.
620 bool MightBeCxx11UnevalField =
621 getLangOpts().CPlusPlus11 && isUnevaluatedContext();
623 // Check if the nested name specifier is an enum type.
625 if (NestedNameSpecifier *NNS = SS.getScopeRep())
626 IsEnum = dyn_cast_or_null<EnumType>(NNS->getAsType());
628 if (!MightBeCxx11UnevalField && !isAddressOfOperand && !IsEnum &&
629 isa<CXXMethodDecl>(DC) && cast<CXXMethodDecl>(DC)->isInstance()) {
630 QualType ThisType = cast<CXXMethodDecl>(DC)->getThisType();
632 // Since the 'this' expression is synthesized, we don't need to
633 // perform the double-lookup check.
634 NamedDecl *FirstQualifierInScope = nullptr;
636 return CXXDependentScopeMemberExpr::Create(
637 Context, /*This*/ nullptr, ThisType, /*IsArrow*/ true,
638 /*Op*/ SourceLocation(), SS.getWithLocInContext(Context), TemplateKWLoc,
639 FirstQualifierInScope, NameInfo, TemplateArgs);
642 return BuildDependentDeclRefExpr(SS, TemplateKWLoc, NameInfo, TemplateArgs);
646 Sema::BuildDependentDeclRefExpr(const CXXScopeSpec &SS,
647 SourceLocation TemplateKWLoc,
648 const DeclarationNameInfo &NameInfo,
649 const TemplateArgumentListInfo *TemplateArgs) {
650 return DependentScopeDeclRefExpr::Create(
651 Context, SS.getWithLocInContext(Context), TemplateKWLoc, NameInfo,
656 /// Determine whether we would be unable to instantiate this template (because
657 /// it either has no definition, or is in the process of being instantiated).
658 bool Sema::DiagnoseUninstantiableTemplate(SourceLocation PointOfInstantiation,
659 NamedDecl *Instantiation,
660 bool InstantiatedFromMember,
661 const NamedDecl *Pattern,
662 const NamedDecl *PatternDef,
663 TemplateSpecializationKind TSK,
664 bool Complain /*= true*/) {
665 assert(isa<TagDecl>(Instantiation) || isa<FunctionDecl>(Instantiation) ||
666 isa<VarDecl>(Instantiation));
668 bool IsEntityBeingDefined = false;
669 if (const TagDecl *TD = dyn_cast_or_null<TagDecl>(PatternDef))
670 IsEntityBeingDefined = TD->isBeingDefined();
672 if (PatternDef && !IsEntityBeingDefined) {
673 NamedDecl *SuggestedDef = nullptr;
674 if (!hasVisibleDefinition(const_cast<NamedDecl*>(PatternDef), &SuggestedDef,
675 /*OnlyNeedComplete*/false)) {
676 // If we're allowed to diagnose this and recover, do so.
677 bool Recover = Complain && !isSFINAEContext();
679 diagnoseMissingImport(PointOfInstantiation, SuggestedDef,
680 Sema::MissingImportKind::Definition, Recover);
686 if (!Complain || (PatternDef && PatternDef->isInvalidDecl()))
689 llvm::Optional<unsigned> Note;
690 QualType InstantiationTy;
691 if (TagDecl *TD = dyn_cast<TagDecl>(Instantiation))
692 InstantiationTy = Context.getTypeDeclType(TD);
694 Diag(PointOfInstantiation,
695 diag::err_template_instantiate_within_definition)
696 << /*implicit|explicit*/(TSK != TSK_ImplicitInstantiation)
698 // Not much point in noting the template declaration here, since
699 // we're lexically inside it.
700 Instantiation->setInvalidDecl();
701 } else if (InstantiatedFromMember) {
702 if (isa<FunctionDecl>(Instantiation)) {
703 Diag(PointOfInstantiation,
704 diag::err_explicit_instantiation_undefined_member)
705 << /*member function*/ 1 << Instantiation->getDeclName()
706 << Instantiation->getDeclContext();
707 Note = diag::note_explicit_instantiation_here;
709 assert(isa<TagDecl>(Instantiation) && "Must be a TagDecl!");
710 Diag(PointOfInstantiation,
711 diag::err_implicit_instantiate_member_undefined)
713 Note = diag::note_member_declared_at;
716 if (isa<FunctionDecl>(Instantiation)) {
717 Diag(PointOfInstantiation,
718 diag::err_explicit_instantiation_undefined_func_template)
720 Note = diag::note_explicit_instantiation_here;
721 } else if (isa<TagDecl>(Instantiation)) {
722 Diag(PointOfInstantiation, diag::err_template_instantiate_undefined)
723 << (TSK != TSK_ImplicitInstantiation)
725 Note = diag::note_template_decl_here;
727 assert(isa<VarDecl>(Instantiation) && "Must be a VarDecl!");
728 if (isa<VarTemplateSpecializationDecl>(Instantiation)) {
729 Diag(PointOfInstantiation,
730 diag::err_explicit_instantiation_undefined_var_template)
732 Instantiation->setInvalidDecl();
734 Diag(PointOfInstantiation,
735 diag::err_explicit_instantiation_undefined_member)
736 << /*static data member*/ 2 << Instantiation->getDeclName()
737 << Instantiation->getDeclContext();
738 Note = diag::note_explicit_instantiation_here;
741 if (Note) // Diagnostics were emitted.
742 Diag(Pattern->getLocation(), Note.getValue());
744 // In general, Instantiation isn't marked invalid to get more than one
745 // error for multiple undefined instantiations. But the code that does
746 // explicit declaration -> explicit definition conversion can't handle
747 // invalid declarations, so mark as invalid in that case.
748 if (TSK == TSK_ExplicitInstantiationDeclaration)
749 Instantiation->setInvalidDecl();
753 /// DiagnoseTemplateParameterShadow - Produce a diagnostic complaining
754 /// that the template parameter 'PrevDecl' is being shadowed by a new
755 /// declaration at location Loc. Returns true to indicate that this is
756 /// an error, and false otherwise.
757 void Sema::DiagnoseTemplateParameterShadow(SourceLocation Loc, Decl *PrevDecl) {
758 assert(PrevDecl->isTemplateParameter() && "Not a template parameter");
760 // Microsoft Visual C++ permits template parameters to be shadowed.
761 if (getLangOpts().MicrosoftExt)
764 // C++ [temp.local]p4:
765 // A template-parameter shall not be redeclared within its
766 // scope (including nested scopes).
767 Diag(Loc, diag::err_template_param_shadow)
768 << cast<NamedDecl>(PrevDecl)->getDeclName();
769 Diag(PrevDecl->getLocation(), diag::note_template_param_here);
772 /// AdjustDeclIfTemplate - If the given decl happens to be a template, reset
773 /// the parameter D to reference the templated declaration and return a pointer
774 /// to the template declaration. Otherwise, do nothing to D and return null.
775 TemplateDecl *Sema::AdjustDeclIfTemplate(Decl *&D) {
776 if (TemplateDecl *Temp = dyn_cast_or_null<TemplateDecl>(D)) {
777 D = Temp->getTemplatedDecl();
783 ParsedTemplateArgument ParsedTemplateArgument::getTemplatePackExpansion(
784 SourceLocation EllipsisLoc) const {
785 assert(Kind == Template &&
786 "Only template template arguments can be pack expansions here");
787 assert(getAsTemplate().get().containsUnexpandedParameterPack() &&
788 "Template template argument pack expansion without packs");
789 ParsedTemplateArgument Result(*this);
790 Result.EllipsisLoc = EllipsisLoc;
794 static TemplateArgumentLoc translateTemplateArgument(Sema &SemaRef,
795 const ParsedTemplateArgument &Arg) {
797 switch (Arg.getKind()) {
798 case ParsedTemplateArgument::Type: {
800 QualType T = SemaRef.GetTypeFromParser(Arg.getAsType(), &DI);
802 DI = SemaRef.Context.getTrivialTypeSourceInfo(T, Arg.getLocation());
803 return TemplateArgumentLoc(TemplateArgument(T), DI);
806 case ParsedTemplateArgument::NonType: {
807 Expr *E = static_cast<Expr *>(Arg.getAsExpr());
808 return TemplateArgumentLoc(TemplateArgument(E), E);
811 case ParsedTemplateArgument::Template: {
812 TemplateName Template = Arg.getAsTemplate().get();
813 TemplateArgument TArg;
814 if (Arg.getEllipsisLoc().isValid())
815 TArg = TemplateArgument(Template, Optional<unsigned int>());
818 return TemplateArgumentLoc(TArg,
819 Arg.getScopeSpec().getWithLocInContext(
822 Arg.getEllipsisLoc());
826 llvm_unreachable("Unhandled parsed template argument");
829 /// Translates template arguments as provided by the parser
830 /// into template arguments used by semantic analysis.
831 void Sema::translateTemplateArguments(const ASTTemplateArgsPtr &TemplateArgsIn,
832 TemplateArgumentListInfo &TemplateArgs) {
833 for (unsigned I = 0, Last = TemplateArgsIn.size(); I != Last; ++I)
834 TemplateArgs.addArgument(translateTemplateArgument(*this,
838 static void maybeDiagnoseTemplateParameterShadow(Sema &SemaRef, Scope *S,
840 IdentifierInfo *Name) {
841 NamedDecl *PrevDecl = SemaRef.LookupSingleName(
842 S, Name, Loc, Sema::LookupOrdinaryName, Sema::ForVisibleRedeclaration);
843 if (PrevDecl && PrevDecl->isTemplateParameter())
844 SemaRef.DiagnoseTemplateParameterShadow(Loc, PrevDecl);
847 /// Convert a parsed type into a parsed template argument. This is mostly
848 /// trivial, except that we may have parsed a C++17 deduced class template
849 /// specialization type, in which case we should form a template template
850 /// argument instead of a type template argument.
851 ParsedTemplateArgument Sema::ActOnTemplateTypeArgument(TypeResult ParsedType) {
852 TypeSourceInfo *TInfo;
853 QualType T = GetTypeFromParser(ParsedType.get(), &TInfo);
855 return ParsedTemplateArgument();
856 assert(TInfo && "template argument with no location");
858 // If we might have formed a deduced template specialization type, convert
859 // it to a template template argument.
860 if (getLangOpts().CPlusPlus17) {
861 TypeLoc TL = TInfo->getTypeLoc();
862 SourceLocation EllipsisLoc;
863 if (auto PET = TL.getAs<PackExpansionTypeLoc>()) {
864 EllipsisLoc = PET.getEllipsisLoc();
865 TL = PET.getPatternLoc();
869 if (auto ET = TL.getAs<ElaboratedTypeLoc>()) {
870 SS.Adopt(ET.getQualifierLoc());
871 TL = ET.getNamedTypeLoc();
874 if (auto DTST = TL.getAs<DeducedTemplateSpecializationTypeLoc>()) {
875 TemplateName Name = DTST.getTypePtr()->getTemplateName();
877 Name = Context.getQualifiedTemplateName(SS.getScopeRep(),
878 /*HasTemplateKeyword*/ false,
879 Name.getAsTemplateDecl());
880 ParsedTemplateArgument Result(SS, TemplateTy::make(Name),
881 DTST.getTemplateNameLoc());
882 if (EllipsisLoc.isValid())
883 Result = Result.getTemplatePackExpansion(EllipsisLoc);
888 // This is a normal type template argument. Note, if the type template
889 // argument is an injected-class-name for a template, it has a dual nature
890 // and can be used as either a type or a template. We handle that in
891 // convertTypeTemplateArgumentToTemplate.
892 return ParsedTemplateArgument(ParsedTemplateArgument::Type,
893 ParsedType.get().getAsOpaquePtr(),
894 TInfo->getTypeLoc().getBeginLoc());
897 /// ActOnTypeParameter - Called when a C++ template type parameter
898 /// (e.g., "typename T") has been parsed. Typename specifies whether
899 /// the keyword "typename" was used to declare the type parameter
900 /// (otherwise, "class" was used), and KeyLoc is the location of the
901 /// "class" or "typename" keyword. ParamName is the name of the
902 /// parameter (NULL indicates an unnamed template parameter) and
903 /// ParamNameLoc is the location of the parameter name (if any).
904 /// If the type parameter has a default argument, it will be added
905 /// later via ActOnTypeParameterDefault.
906 NamedDecl *Sema::ActOnTypeParameter(Scope *S, bool Typename,
907 SourceLocation EllipsisLoc,
908 SourceLocation KeyLoc,
909 IdentifierInfo *ParamName,
910 SourceLocation ParamNameLoc,
911 unsigned Depth, unsigned Position,
912 SourceLocation EqualLoc,
913 ParsedType DefaultArg) {
914 assert(S->isTemplateParamScope() &&
915 "Template type parameter not in template parameter scope!");
917 SourceLocation Loc = ParamNameLoc;
921 bool IsParameterPack = EllipsisLoc.isValid();
922 TemplateTypeParmDecl *Param
923 = TemplateTypeParmDecl::Create(Context, Context.getTranslationUnitDecl(),
924 KeyLoc, Loc, Depth, Position, ParamName,
925 Typename, IsParameterPack);
926 Param->setAccess(AS_public);
929 maybeDiagnoseTemplateParameterShadow(*this, S, ParamNameLoc, ParamName);
931 // Add the template parameter into the current scope.
933 IdResolver.AddDecl(Param);
936 // C++0x [temp.param]p9:
937 // A default template-argument may be specified for any kind of
938 // template-parameter that is not a template parameter pack.
939 if (DefaultArg && IsParameterPack) {
940 Diag(EqualLoc, diag::err_template_param_pack_default_arg);
941 DefaultArg = nullptr;
944 // Handle the default argument, if provided.
946 TypeSourceInfo *DefaultTInfo;
947 GetTypeFromParser(DefaultArg, &DefaultTInfo);
949 assert(DefaultTInfo && "expected source information for type");
951 // Check for unexpanded parameter packs.
952 if (DiagnoseUnexpandedParameterPack(Loc, DefaultTInfo,
953 UPPC_DefaultArgument))
956 // Check the template argument itself.
957 if (CheckTemplateArgument(Param, DefaultTInfo)) {
958 Param->setInvalidDecl();
962 Param->setDefaultArgument(DefaultTInfo);
968 /// Check that the type of a non-type template parameter is
971 /// \returns the (possibly-promoted) parameter type if valid;
972 /// otherwise, produces a diagnostic and returns a NULL type.
973 QualType Sema::CheckNonTypeTemplateParameterType(TypeSourceInfo *&TSI,
974 SourceLocation Loc) {
975 if (TSI->getType()->isUndeducedType()) {
976 // C++17 [temp.dep.expr]p3:
977 // An id-expression is type-dependent if it contains
978 // - an identifier associated by name lookup with a non-type
979 // template-parameter declared with a type that contains a
980 // placeholder type (7.1.7.4),
981 TSI = SubstAutoTypeSourceInfo(TSI, Context.DependentTy);
984 return CheckNonTypeTemplateParameterType(TSI->getType(), Loc);
987 QualType Sema::CheckNonTypeTemplateParameterType(QualType T,
988 SourceLocation Loc) {
989 // We don't allow variably-modified types as the type of non-type template
991 if (T->isVariablyModifiedType()) {
992 Diag(Loc, diag::err_variably_modified_nontype_template_param)
997 // C++ [temp.param]p4:
999 // A non-type template-parameter shall have one of the following
1000 // (optionally cv-qualified) types:
1002 // -- integral or enumeration type,
1003 if (T->isIntegralOrEnumerationType() ||
1004 // -- pointer to object or pointer to function,
1005 T->isPointerType() ||
1006 // -- reference to object or reference to function,
1007 T->isReferenceType() ||
1008 // -- pointer to member,
1009 T->isMemberPointerType() ||
1010 // -- std::nullptr_t.
1011 T->isNullPtrType() ||
1012 // If T is a dependent type, we can't do the check now, so we
1013 // assume that it is well-formed.
1014 T->isDependentType() ||
1015 // Allow use of auto in template parameter declarations.
1016 T->isUndeducedType()) {
1017 // C++ [temp.param]p5: The top-level cv-qualifiers on the template-parameter
1018 // are ignored when determining its type.
1019 return T.getUnqualifiedType();
1022 // C++ [temp.param]p8:
1024 // A non-type template-parameter of type "array of T" or
1025 // "function returning T" is adjusted to be of type "pointer to
1026 // T" or "pointer to function returning T", respectively.
1027 else if (T->isArrayType() || T->isFunctionType())
1028 return Context.getDecayedType(T);
1030 Diag(Loc, diag::err_template_nontype_parm_bad_type)
1036 NamedDecl *Sema::ActOnNonTypeTemplateParameter(Scope *S, Declarator &D,
1039 SourceLocation EqualLoc,
1041 TypeSourceInfo *TInfo = GetTypeForDeclarator(D, S);
1043 // Check that we have valid decl-specifiers specified.
1044 auto CheckValidDeclSpecifiers = [this, &D] {
1047 // template-parameter:
1049 // parameter-declaration
1051 // ... A storage class shall not be specified in a template-parameter
1054 // The typedef specifier [...] shall not be used in the decl-specifier-seq
1055 // of a parameter-declaration
1056 const DeclSpec &DS = D.getDeclSpec();
1057 auto EmitDiag = [this](SourceLocation Loc) {
1058 Diag(Loc, diag::err_invalid_decl_specifier_in_nontype_parm)
1059 << FixItHint::CreateRemoval(Loc);
1061 if (DS.getStorageClassSpec() != DeclSpec::SCS_unspecified)
1062 EmitDiag(DS.getStorageClassSpecLoc());
1064 if (DS.getThreadStorageClassSpec() != TSCS_unspecified)
1065 EmitDiag(DS.getThreadStorageClassSpecLoc());
1068 // The inline specifier can be applied only to the declaration or
1069 // definition of a variable or function.
1071 if (DS.isInlineSpecified())
1072 EmitDiag(DS.getInlineSpecLoc());
1074 // [dcl.constexpr]p1:
1075 // The constexpr specifier shall be applied only to the definition of a
1076 // variable or variable template or the declaration of a function or
1077 // function template.
1079 if (DS.isConstexprSpecified())
1080 EmitDiag(DS.getConstexprSpecLoc());
1082 // [dcl.fct.spec]p1:
1083 // Function-specifiers can be used only in function declarations.
1085 if (DS.isVirtualSpecified())
1086 EmitDiag(DS.getVirtualSpecLoc());
1088 if (DS.isExplicitSpecified())
1089 EmitDiag(DS.getExplicitSpecLoc());
1091 if (DS.isNoreturnSpecified())
1092 EmitDiag(DS.getNoreturnSpecLoc());
1095 CheckValidDeclSpecifiers();
1097 if (TInfo->getType()->isUndeducedType()) {
1098 Diag(D.getIdentifierLoc(),
1099 diag::warn_cxx14_compat_template_nontype_parm_auto_type)
1100 << QualType(TInfo->getType()->getContainedAutoType(), 0);
1103 assert(S->isTemplateParamScope() &&
1104 "Non-type template parameter not in template parameter scope!");
1105 bool Invalid = false;
1107 QualType T = CheckNonTypeTemplateParameterType(TInfo, D.getIdentifierLoc());
1109 T = Context.IntTy; // Recover with an 'int' type.
1113 IdentifierInfo *ParamName = D.getIdentifier();
1114 bool IsParameterPack = D.hasEllipsis();
1115 NonTypeTemplateParmDecl *Param = NonTypeTemplateParmDecl::Create(
1116 Context, Context.getTranslationUnitDecl(), D.getBeginLoc(),
1117 D.getIdentifierLoc(), Depth, Position, ParamName, T, IsParameterPack,
1119 Param->setAccess(AS_public);
1122 Param->setInvalidDecl();
1125 maybeDiagnoseTemplateParameterShadow(*this, S, D.getIdentifierLoc(),
1128 // Add the template parameter into the current scope.
1130 IdResolver.AddDecl(Param);
1133 // C++0x [temp.param]p9:
1134 // A default template-argument may be specified for any kind of
1135 // template-parameter that is not a template parameter pack.
1136 if (Default && IsParameterPack) {
1137 Diag(EqualLoc, diag::err_template_param_pack_default_arg);
1141 // Check the well-formedness of the default template argument, if provided.
1143 // Check for unexpanded parameter packs.
1144 if (DiagnoseUnexpandedParameterPack(Default, UPPC_DefaultArgument))
1147 TemplateArgument Converted;
1148 ExprResult DefaultRes =
1149 CheckTemplateArgument(Param, Param->getType(), Default, Converted);
1150 if (DefaultRes.isInvalid()) {
1151 Param->setInvalidDecl();
1154 Default = DefaultRes.get();
1156 Param->setDefaultArgument(Default);
1162 /// ActOnTemplateTemplateParameter - Called when a C++ template template
1163 /// parameter (e.g. T in template <template \<typename> class T> class array)
1164 /// has been parsed. S is the current scope.
1165 NamedDecl *Sema::ActOnTemplateTemplateParameter(Scope* S,
1166 SourceLocation TmpLoc,
1167 TemplateParameterList *Params,
1168 SourceLocation EllipsisLoc,
1169 IdentifierInfo *Name,
1170 SourceLocation NameLoc,
1173 SourceLocation EqualLoc,
1174 ParsedTemplateArgument Default) {
1175 assert(S->isTemplateParamScope() &&
1176 "Template template parameter not in template parameter scope!");
1178 // Construct the parameter object.
1179 bool IsParameterPack = EllipsisLoc.isValid();
1180 TemplateTemplateParmDecl *Param =
1181 TemplateTemplateParmDecl::Create(Context, Context.getTranslationUnitDecl(),
1182 NameLoc.isInvalid()? TmpLoc : NameLoc,
1183 Depth, Position, IsParameterPack,
1185 Param->setAccess(AS_public);
1187 // If the template template parameter has a name, then link the identifier
1188 // into the scope and lookup mechanisms.
1190 maybeDiagnoseTemplateParameterShadow(*this, S, NameLoc, Name);
1193 IdResolver.AddDecl(Param);
1196 if (Params->size() == 0) {
1197 Diag(Param->getLocation(), diag::err_template_template_parm_no_parms)
1198 << SourceRange(Params->getLAngleLoc(), Params->getRAngleLoc());
1199 Param->setInvalidDecl();
1202 // C++0x [temp.param]p9:
1203 // A default template-argument may be specified for any kind of
1204 // template-parameter that is not a template parameter pack.
1205 if (IsParameterPack && !Default.isInvalid()) {
1206 Diag(EqualLoc, diag::err_template_param_pack_default_arg);
1207 Default = ParsedTemplateArgument();
1210 if (!Default.isInvalid()) {
1211 // Check only that we have a template template argument. We don't want to
1212 // try to check well-formedness now, because our template template parameter
1213 // might have dependent types in its template parameters, which we wouldn't
1214 // be able to match now.
1216 // If none of the template template parameter's template arguments mention
1217 // other template parameters, we could actually perform more checking here.
1218 // However, it isn't worth doing.
1219 TemplateArgumentLoc DefaultArg = translateTemplateArgument(*this, Default);
1220 if (DefaultArg.getArgument().getAsTemplate().isNull()) {
1221 Diag(DefaultArg.getLocation(), diag::err_template_arg_not_valid_template)
1222 << DefaultArg.getSourceRange();
1226 // Check for unexpanded parameter packs.
1227 if (DiagnoseUnexpandedParameterPack(DefaultArg.getLocation(),
1228 DefaultArg.getArgument().getAsTemplate(),
1229 UPPC_DefaultArgument))
1232 Param->setDefaultArgument(Context, DefaultArg);
1238 /// ActOnTemplateParameterList - Builds a TemplateParameterList, optionally
1239 /// constrained by RequiresClause, that contains the template parameters in
1241 TemplateParameterList *
1242 Sema::ActOnTemplateParameterList(unsigned Depth,
1243 SourceLocation ExportLoc,
1244 SourceLocation TemplateLoc,
1245 SourceLocation LAngleLoc,
1246 ArrayRef<NamedDecl *> Params,
1247 SourceLocation RAngleLoc,
1248 Expr *RequiresClause) {
1249 if (ExportLoc.isValid())
1250 Diag(ExportLoc, diag::warn_template_export_unsupported);
1252 return TemplateParameterList::Create(
1253 Context, TemplateLoc, LAngleLoc,
1254 llvm::makeArrayRef(Params.data(), Params.size()),
1255 RAngleLoc, RequiresClause);
1258 static void SetNestedNameSpecifier(Sema &S, TagDecl *T,
1259 const CXXScopeSpec &SS) {
1261 T->setQualifierInfo(SS.getWithLocInContext(S.Context));
1264 DeclResult Sema::CheckClassTemplate(
1265 Scope *S, unsigned TagSpec, TagUseKind TUK, SourceLocation KWLoc,
1266 CXXScopeSpec &SS, IdentifierInfo *Name, SourceLocation NameLoc,
1267 const ParsedAttributesView &Attr, TemplateParameterList *TemplateParams,
1268 AccessSpecifier AS, SourceLocation ModulePrivateLoc,
1269 SourceLocation FriendLoc, unsigned NumOuterTemplateParamLists,
1270 TemplateParameterList **OuterTemplateParamLists, SkipBodyInfo *SkipBody) {
1271 assert(TemplateParams && TemplateParams->size() > 0 &&
1272 "No template parameters");
1273 assert(TUK != TUK_Reference && "Can only declare or define class templates");
1274 bool Invalid = false;
1276 // Check that we can declare a template here.
1277 if (CheckTemplateDeclScope(S, TemplateParams))
1280 TagTypeKind Kind = TypeWithKeyword::getTagTypeKindForTypeSpec(TagSpec);
1281 assert(Kind != TTK_Enum && "can't build template of enumerated type");
1283 // There is no such thing as an unnamed class template.
1285 Diag(KWLoc, diag::err_template_unnamed_class);
1289 // Find any previous declaration with this name. For a friend with no
1290 // scope explicitly specified, we only look for tag declarations (per
1291 // C++11 [basic.lookup.elab]p2).
1292 DeclContext *SemanticContext;
1293 LookupResult Previous(*this, Name, NameLoc,
1294 (SS.isEmpty() && TUK == TUK_Friend)
1295 ? LookupTagName : LookupOrdinaryName,
1296 forRedeclarationInCurContext());
1297 if (SS.isNotEmpty() && !SS.isInvalid()) {
1298 SemanticContext = computeDeclContext(SS, true);
1299 if (!SemanticContext) {
1300 // FIXME: Horrible, horrible hack! We can't currently represent this
1301 // in the AST, and historically we have just ignored such friend
1302 // class templates, so don't complain here.
1303 Diag(NameLoc, TUK == TUK_Friend
1304 ? diag::warn_template_qualified_friend_ignored
1305 : diag::err_template_qualified_declarator_no_match)
1306 << SS.getScopeRep() << SS.getRange();
1307 return TUK != TUK_Friend;
1310 if (RequireCompleteDeclContext(SS, SemanticContext))
1313 // If we're adding a template to a dependent context, we may need to
1314 // rebuilding some of the types used within the template parameter list,
1315 // now that we know what the current instantiation is.
1316 if (SemanticContext->isDependentContext()) {
1317 ContextRAII SavedContext(*this, SemanticContext);
1318 if (RebuildTemplateParamsInCurrentInstantiation(TemplateParams))
1320 } else if (TUK != TUK_Friend && TUK != TUK_Reference)
1321 diagnoseQualifiedDeclaration(SS, SemanticContext, Name, NameLoc, false);
1323 LookupQualifiedName(Previous, SemanticContext);
1325 SemanticContext = CurContext;
1327 // C++14 [class.mem]p14:
1328 // If T is the name of a class, then each of the following shall have a
1329 // name different from T:
1330 // -- every member template of class T
1331 if (TUK != TUK_Friend &&
1332 DiagnoseClassNameShadow(SemanticContext,
1333 DeclarationNameInfo(Name, NameLoc)))
1336 LookupName(Previous, S);
1339 if (Previous.isAmbiguous())
1342 NamedDecl *PrevDecl = nullptr;
1343 if (Previous.begin() != Previous.end())
1344 PrevDecl = (*Previous.begin())->getUnderlyingDecl();
1346 if (PrevDecl && PrevDecl->isTemplateParameter()) {
1347 // Maybe we will complain about the shadowed template parameter.
1348 DiagnoseTemplateParameterShadow(NameLoc, PrevDecl);
1349 // Just pretend that we didn't see the previous declaration.
1353 // If there is a previous declaration with the same name, check
1354 // whether this is a valid redeclaration.
1355 ClassTemplateDecl *PrevClassTemplate =
1356 dyn_cast_or_null<ClassTemplateDecl>(PrevDecl);
1358 // We may have found the injected-class-name of a class template,
1359 // class template partial specialization, or class template specialization.
1360 // In these cases, grab the template that is being defined or specialized.
1361 if (!PrevClassTemplate && PrevDecl && isa<CXXRecordDecl>(PrevDecl) &&
1362 cast<CXXRecordDecl>(PrevDecl)->isInjectedClassName()) {
1363 PrevDecl = cast<CXXRecordDecl>(PrevDecl->getDeclContext());
1365 = cast<CXXRecordDecl>(PrevDecl)->getDescribedClassTemplate();
1366 if (!PrevClassTemplate && isa<ClassTemplateSpecializationDecl>(PrevDecl)) {
1368 = cast<ClassTemplateSpecializationDecl>(PrevDecl)
1369 ->getSpecializedTemplate();
1373 if (TUK == TUK_Friend) {
1374 // C++ [namespace.memdef]p3:
1375 // [...] When looking for a prior declaration of a class or a function
1376 // declared as a friend, and when the name of the friend class or
1377 // function is neither a qualified name nor a template-id, scopes outside
1378 // the innermost enclosing namespace scope are not considered.
1380 DeclContext *OutermostContext = CurContext;
1381 while (!OutermostContext->isFileContext())
1382 OutermostContext = OutermostContext->getLookupParent();
1385 (OutermostContext->Equals(PrevDecl->getDeclContext()) ||
1386 OutermostContext->Encloses(PrevDecl->getDeclContext()))) {
1387 SemanticContext = PrevDecl->getDeclContext();
1389 // Declarations in outer scopes don't matter. However, the outermost
1390 // context we computed is the semantic context for our new
1392 PrevDecl = PrevClassTemplate = nullptr;
1393 SemanticContext = OutermostContext;
1395 // Check that the chosen semantic context doesn't already contain a
1396 // declaration of this name as a non-tag type.
1397 Previous.clear(LookupOrdinaryName);
1398 DeclContext *LookupContext = SemanticContext;
1399 while (LookupContext->isTransparentContext())
1400 LookupContext = LookupContext->getLookupParent();
1401 LookupQualifiedName(Previous, LookupContext);
1403 if (Previous.isAmbiguous())
1406 if (Previous.begin() != Previous.end())
1407 PrevDecl = (*Previous.begin())->getUnderlyingDecl();
1410 } else if (PrevDecl &&
1411 !isDeclInScope(Previous.getRepresentativeDecl(), SemanticContext,
1413 PrevDecl = PrevClassTemplate = nullptr;
1415 if (auto *Shadow = dyn_cast_or_null<UsingShadowDecl>(
1416 PrevDecl ? Previous.getRepresentativeDecl() : nullptr)) {
1418 !(PrevClassTemplate &&
1419 PrevClassTemplate->getDeclContext()->getRedeclContext()->Equals(
1420 SemanticContext->getRedeclContext()))) {
1421 Diag(KWLoc, diag::err_using_decl_conflict_reverse);
1422 Diag(Shadow->getTargetDecl()->getLocation(),
1423 diag::note_using_decl_target);
1424 Diag(Shadow->getUsingDecl()->getLocation(), diag::note_using_decl) << 0;
1425 // Recover by ignoring the old declaration.
1426 PrevDecl = PrevClassTemplate = nullptr;
1430 // TODO Memory management; associated constraints are not always stored.
1431 Expr *const CurAC = formAssociatedConstraints(TemplateParams, nullptr);
1433 if (PrevClassTemplate) {
1434 // Ensure that the template parameter lists are compatible. Skip this check
1435 // for a friend in a dependent context: the template parameter list itself
1436 // could be dependent.
1437 if (!(TUK == TUK_Friend && CurContext->isDependentContext()) &&
1438 !TemplateParameterListsAreEqual(TemplateParams,
1439 PrevClassTemplate->getTemplateParameters(),
1444 // Check for matching associated constraints on redeclarations.
1445 const Expr *const PrevAC = PrevClassTemplate->getAssociatedConstraints();
1446 const bool RedeclACMismatch = [&] {
1447 if (!(CurAC || PrevAC))
1448 return false; // Nothing to check; no mismatch.
1449 if (CurAC && PrevAC) {
1450 llvm::FoldingSetNodeID CurACInfo, PrevACInfo;
1451 CurAC->Profile(CurACInfo, Context, /*Canonical=*/true);
1452 PrevAC->Profile(PrevACInfo, Context, /*Canonical=*/true);
1453 if (CurACInfo == PrevACInfo)
1454 return false; // All good; no mismatch.
1459 if (RedeclACMismatch) {
1460 Diag(CurAC ? CurAC->getBeginLoc() : NameLoc,
1461 diag::err_template_different_associated_constraints);
1462 Diag(PrevAC ? PrevAC->getBeginLoc() : PrevClassTemplate->getLocation(),
1463 diag::note_template_prev_declaration)
1464 << /*declaration*/ 0;
1468 // C++ [temp.class]p4:
1469 // In a redeclaration, partial specialization, explicit
1470 // specialization or explicit instantiation of a class template,
1471 // the class-key shall agree in kind with the original class
1472 // template declaration (7.1.5.3).
1473 RecordDecl *PrevRecordDecl = PrevClassTemplate->getTemplatedDecl();
1474 if (!isAcceptableTagRedeclaration(PrevRecordDecl, Kind,
1475 TUK == TUK_Definition, KWLoc, Name)) {
1476 Diag(KWLoc, diag::err_use_with_wrong_tag)
1478 << FixItHint::CreateReplacement(KWLoc, PrevRecordDecl->getKindName());
1479 Diag(PrevRecordDecl->getLocation(), diag::note_previous_use);
1480 Kind = PrevRecordDecl->getTagKind();
1483 // Check for redefinition of this class template.
1484 if (TUK == TUK_Definition) {
1485 if (TagDecl *Def = PrevRecordDecl->getDefinition()) {
1486 // If we have a prior definition that is not visible, treat this as
1487 // simply making that previous definition visible.
1488 NamedDecl *Hidden = nullptr;
1489 if (SkipBody && !hasVisibleDefinition(Def, &Hidden)) {
1490 SkipBody->ShouldSkip = true;
1491 SkipBody->Previous = Def;
1492 auto *Tmpl = cast<CXXRecordDecl>(Hidden)->getDescribedClassTemplate();
1493 assert(Tmpl && "original definition of a class template is not a "
1495 makeMergedDefinitionVisible(Hidden);
1496 makeMergedDefinitionVisible(Tmpl);
1498 Diag(NameLoc, diag::err_redefinition) << Name;
1499 Diag(Def->getLocation(), diag::note_previous_definition);
1500 // FIXME: Would it make sense to try to "forget" the previous
1501 // definition, as part of error recovery?
1506 } else if (PrevDecl) {
1508 // A class template shall not have the same name as any other
1509 // template, class, function, object, enumeration, enumerator,
1510 // namespace, or type in the same scope (3.3), except as specified
1512 Diag(NameLoc, diag::err_redefinition_different_kind) << Name;
1513 Diag(PrevDecl->getLocation(), diag::note_previous_definition);
1517 // Check the template parameter list of this declaration, possibly
1518 // merging in the template parameter list from the previous class
1519 // template declaration. Skip this check for a friend in a dependent
1520 // context, because the template parameter list might be dependent.
1521 if (!(TUK == TUK_Friend && CurContext->isDependentContext()) &&
1522 CheckTemplateParameterList(
1525 ? PrevClassTemplate->getMostRecentDecl()->getTemplateParameters()
1527 (SS.isSet() && SemanticContext && SemanticContext->isRecord() &&
1528 SemanticContext->isDependentContext())
1529 ? TPC_ClassTemplateMember
1530 : TUK == TUK_Friend ? TPC_FriendClassTemplate : TPC_ClassTemplate,
1535 // If the name of the template was qualified, we must be defining the
1536 // template out-of-line.
1537 if (!SS.isInvalid() && !Invalid && !PrevClassTemplate) {
1538 Diag(NameLoc, TUK == TUK_Friend ? diag::err_friend_decl_does_not_match
1539 : diag::err_member_decl_does_not_match)
1540 << Name << SemanticContext << /*IsDefinition*/true << SS.getRange();
1545 // If this is a templated friend in a dependent context we should not put it
1546 // on the redecl chain. In some cases, the templated friend can be the most
1547 // recent declaration tricking the template instantiator to make substitutions
1549 // FIXME: Figure out how to combine with shouldLinkDependentDeclWithPrevious
1550 bool ShouldAddRedecl
1551 = !(TUK == TUK_Friend && CurContext->isDependentContext());
1553 CXXRecordDecl *NewClass =
1554 CXXRecordDecl::Create(Context, Kind, SemanticContext, KWLoc, NameLoc, Name,
1555 PrevClassTemplate && ShouldAddRedecl ?
1556 PrevClassTemplate->getTemplatedDecl() : nullptr,
1557 /*DelayTypeCreation=*/true);
1558 SetNestedNameSpecifier(*this, NewClass, SS);
1559 if (NumOuterTemplateParamLists > 0)
1560 NewClass->setTemplateParameterListsInfo(
1561 Context, llvm::makeArrayRef(OuterTemplateParamLists,
1562 NumOuterTemplateParamLists));
1564 // Add alignment attributes if necessary; these attributes are checked when
1565 // the ASTContext lays out the structure.
1566 if (TUK == TUK_Definition && (!SkipBody || !SkipBody->ShouldSkip)) {
1567 AddAlignmentAttributesForRecord(NewClass);
1568 AddMsStructLayoutForRecord(NewClass);
1571 // Attach the associated constraints when the declaration will not be part of
1573 Expr *const ACtoAttach =
1574 PrevClassTemplate && ShouldAddRedecl ? nullptr : CurAC;
1576 ClassTemplateDecl *NewTemplate
1577 = ClassTemplateDecl::Create(Context, SemanticContext, NameLoc,
1578 DeclarationName(Name), TemplateParams,
1579 NewClass, ACtoAttach);
1581 if (ShouldAddRedecl)
1582 NewTemplate->setPreviousDecl(PrevClassTemplate);
1584 NewClass->setDescribedClassTemplate(NewTemplate);
1586 if (ModulePrivateLoc.isValid())
1587 NewTemplate->setModulePrivate();
1589 // Build the type for the class template declaration now.
1590 QualType T = NewTemplate->getInjectedClassNameSpecialization();
1591 T = Context.getInjectedClassNameType(NewClass, T);
1592 assert(T->isDependentType() && "Class template type is not dependent?");
1595 // If we are providing an explicit specialization of a member that is a
1596 // class template, make a note of that.
1597 if (PrevClassTemplate &&
1598 PrevClassTemplate->getInstantiatedFromMemberTemplate())
1599 PrevClassTemplate->setMemberSpecialization();
1601 // Set the access specifier.
1602 if (!Invalid && TUK != TUK_Friend && NewTemplate->getDeclContext()->isRecord())
1603 SetMemberAccessSpecifier(NewTemplate, PrevClassTemplate, AS);
1605 // Set the lexical context of these templates
1606 NewClass->setLexicalDeclContext(CurContext);
1607 NewTemplate->setLexicalDeclContext(CurContext);
1609 if (TUK == TUK_Definition && (!SkipBody || !SkipBody->ShouldSkip))
1610 NewClass->startDefinition();
1612 ProcessDeclAttributeList(S, NewClass, Attr);
1614 if (PrevClassTemplate)
1615 mergeDeclAttributes(NewClass, PrevClassTemplate->getTemplatedDecl());
1617 AddPushedVisibilityAttribute(NewClass);
1619 if (TUK != TUK_Friend) {
1620 // Per C++ [basic.scope.temp]p2, skip the template parameter scopes.
1622 while ((Outer->getFlags() & Scope::TemplateParamScope) != 0)
1623 Outer = Outer->getParent();
1624 PushOnScopeChains(NewTemplate, Outer);
1626 if (PrevClassTemplate && PrevClassTemplate->getAccess() != AS_none) {
1627 NewTemplate->setAccess(PrevClassTemplate->getAccess());
1628 NewClass->setAccess(PrevClassTemplate->getAccess());
1631 NewTemplate->setObjectOfFriendDecl();
1633 // Friend templates are visible in fairly strange ways.
1634 if (!CurContext->isDependentContext()) {
1635 DeclContext *DC = SemanticContext->getRedeclContext();
1636 DC->makeDeclVisibleInContext(NewTemplate);
1637 if (Scope *EnclosingScope = getScopeForDeclContext(S, DC))
1638 PushOnScopeChains(NewTemplate, EnclosingScope,
1639 /* AddToContext = */ false);
1642 FriendDecl *Friend = FriendDecl::Create(
1643 Context, CurContext, NewClass->getLocation(), NewTemplate, FriendLoc);
1644 Friend->setAccess(AS_public);
1645 CurContext->addDecl(Friend);
1648 if (PrevClassTemplate)
1649 CheckRedeclarationModuleOwnership(NewTemplate, PrevClassTemplate);
1652 NewTemplate->setInvalidDecl();
1653 NewClass->setInvalidDecl();
1656 ActOnDocumentableDecl(NewTemplate);
1658 if (SkipBody && SkipBody->ShouldSkip)
1659 return SkipBody->Previous;
1665 /// Tree transform to "extract" a transformed type from a class template's
1666 /// constructor to a deduction guide.
1667 class ExtractTypeForDeductionGuide
1668 : public TreeTransform<ExtractTypeForDeductionGuide> {
1670 typedef TreeTransform<ExtractTypeForDeductionGuide> Base;
1671 ExtractTypeForDeductionGuide(Sema &SemaRef) : Base(SemaRef) {}
1673 TypeSourceInfo *transform(TypeSourceInfo *TSI) { return TransformType(TSI); }
1675 QualType TransformTypedefType(TypeLocBuilder &TLB, TypedefTypeLoc TL) {
1676 return TransformType(
1678 TL.getTypedefNameDecl()->getTypeSourceInfo()->getTypeLoc());
1682 /// Transform to convert portions of a constructor declaration into the
1683 /// corresponding deduction guide, per C++1z [over.match.class.deduct]p1.
1684 struct ConvertConstructorToDeductionGuideTransform {
1685 ConvertConstructorToDeductionGuideTransform(Sema &S,
1686 ClassTemplateDecl *Template)
1687 : SemaRef(S), Template(Template) {}
1690 ClassTemplateDecl *Template;
1692 DeclContext *DC = Template->getDeclContext();
1693 CXXRecordDecl *Primary = Template->getTemplatedDecl();
1694 DeclarationName DeductionGuideName =
1695 SemaRef.Context.DeclarationNames.getCXXDeductionGuideName(Template);
1697 QualType DeducedType = SemaRef.Context.getTypeDeclType(Primary);
1699 // Index adjustment to apply to convert depth-1 template parameters into
1700 // depth-0 template parameters.
1701 unsigned Depth1IndexAdjustment = Template->getTemplateParameters()->size();
1703 /// Transform a constructor declaration into a deduction guide.
1704 NamedDecl *transformConstructor(FunctionTemplateDecl *FTD,
1705 CXXConstructorDecl *CD) {
1706 SmallVector<TemplateArgument, 16> SubstArgs;
1708 LocalInstantiationScope Scope(SemaRef);
1710 // C++ [over.match.class.deduct]p1:
1711 // -- For each constructor of the class template designated by the
1712 // template-name, a function template with the following properties:
1714 // -- The template parameters are the template parameters of the class
1715 // template followed by the template parameters (including default
1716 // template arguments) of the constructor, if any.
1717 TemplateParameterList *TemplateParams = Template->getTemplateParameters();
1719 TemplateParameterList *InnerParams = FTD->getTemplateParameters();
1720 SmallVector<NamedDecl *, 16> AllParams;
1721 AllParams.reserve(TemplateParams->size() + InnerParams->size());
1722 AllParams.insert(AllParams.begin(),
1723 TemplateParams->begin(), TemplateParams->end());
1724 SubstArgs.reserve(InnerParams->size());
1726 // Later template parameters could refer to earlier ones, so build up
1727 // a list of substituted template arguments as we go.
1728 for (NamedDecl *Param : *InnerParams) {
1729 MultiLevelTemplateArgumentList Args;
1730 Args.addOuterTemplateArguments(SubstArgs);
1731 Args.addOuterRetainedLevel();
1732 NamedDecl *NewParam = transformTemplateParameter(Param, Args);
1735 AllParams.push_back(NewParam);
1736 SubstArgs.push_back(SemaRef.Context.getCanonicalTemplateArgument(
1737 SemaRef.Context.getInjectedTemplateArg(NewParam)));
1739 TemplateParams = TemplateParameterList::Create(
1740 SemaRef.Context, InnerParams->getTemplateLoc(),
1741 InnerParams->getLAngleLoc(), AllParams, InnerParams->getRAngleLoc(),
1742 /*FIXME: RequiresClause*/ nullptr);
1745 // If we built a new template-parameter-list, track that we need to
1746 // substitute references to the old parameters into references to the
1748 MultiLevelTemplateArgumentList Args;
1750 Args.addOuterTemplateArguments(SubstArgs);
1751 Args.addOuterRetainedLevel();
1754 FunctionProtoTypeLoc FPTL = CD->getTypeSourceInfo()->getTypeLoc()
1755 .getAsAdjusted<FunctionProtoTypeLoc>();
1756 assert(FPTL && "no prototype for constructor declaration");
1758 // Transform the type of the function, adjusting the return type and
1759 // replacing references to the old parameters with references to the
1762 SmallVector<ParmVarDecl*, 8> Params;
1763 QualType NewType = transformFunctionProtoType(TLB, FPTL, Params, Args);
1764 if (NewType.isNull())
1766 TypeSourceInfo *NewTInfo = TLB.getTypeSourceInfo(SemaRef.Context, NewType);
1768 return buildDeductionGuide(TemplateParams, CD->isExplicit(), NewTInfo,
1769 CD->getBeginLoc(), CD->getLocation(),
1773 /// Build a deduction guide with the specified parameter types.
1774 NamedDecl *buildSimpleDeductionGuide(MutableArrayRef<QualType> ParamTypes) {
1775 SourceLocation Loc = Template->getLocation();
1777 // Build the requested type.
1778 FunctionProtoType::ExtProtoInfo EPI;
1779 EPI.HasTrailingReturn = true;
1780 QualType Result = SemaRef.BuildFunctionType(DeducedType, ParamTypes, Loc,
1781 DeductionGuideName, EPI);
1782 TypeSourceInfo *TSI = SemaRef.Context.getTrivialTypeSourceInfo(Result, Loc);
1784 FunctionProtoTypeLoc FPTL =
1785 TSI->getTypeLoc().castAs<FunctionProtoTypeLoc>();
1787 // Build the parameters, needed during deduction / substitution.
1788 SmallVector<ParmVarDecl*, 4> Params;
1789 for (auto T : ParamTypes) {
1790 ParmVarDecl *NewParam = ParmVarDecl::Create(
1791 SemaRef.Context, DC, Loc, Loc, nullptr, T,
1792 SemaRef.Context.getTrivialTypeSourceInfo(T, Loc), SC_None, nullptr);
1793 NewParam->setScopeInfo(0, Params.size());
1794 FPTL.setParam(Params.size(), NewParam);
1795 Params.push_back(NewParam);
1798 return buildDeductionGuide(Template->getTemplateParameters(), false, TSI,
1803 /// Transform a constructor template parameter into a deduction guide template
1804 /// parameter, rebuilding any internal references to earlier parameters and
1805 /// renumbering as we go.
1806 NamedDecl *transformTemplateParameter(NamedDecl *TemplateParam,
1807 MultiLevelTemplateArgumentList &Args) {
1808 if (auto *TTP = dyn_cast<TemplateTypeParmDecl>(TemplateParam)) {
1809 // TemplateTypeParmDecl's index cannot be changed after creation, so
1810 // substitute it directly.
1811 auto *NewTTP = TemplateTypeParmDecl::Create(
1812 SemaRef.Context, DC, TTP->getBeginLoc(), TTP->getLocation(),
1813 /*Depth*/ 0, Depth1IndexAdjustment + TTP->getIndex(),
1814 TTP->getIdentifier(), TTP->wasDeclaredWithTypename(),
1815 TTP->isParameterPack());
1816 if (TTP->hasDefaultArgument()) {
1817 TypeSourceInfo *InstantiatedDefaultArg =
1818 SemaRef.SubstType(TTP->getDefaultArgumentInfo(), Args,
1819 TTP->getDefaultArgumentLoc(), TTP->getDeclName());
1820 if (InstantiatedDefaultArg)
1821 NewTTP->setDefaultArgument(InstantiatedDefaultArg);
1823 SemaRef.CurrentInstantiationScope->InstantiatedLocal(TemplateParam,
1828 if (auto *TTP = dyn_cast<TemplateTemplateParmDecl>(TemplateParam))
1829 return transformTemplateParameterImpl(TTP, Args);
1831 return transformTemplateParameterImpl(
1832 cast<NonTypeTemplateParmDecl>(TemplateParam), Args);
1834 template<typename TemplateParmDecl>
1836 transformTemplateParameterImpl(TemplateParmDecl *OldParam,
1837 MultiLevelTemplateArgumentList &Args) {
1838 // Ask the template instantiator to do the heavy lifting for us, then adjust
1839 // the index of the parameter once it's done.
1841 cast_or_null<TemplateParmDecl>(SemaRef.SubstDecl(OldParam, DC, Args));
1842 assert(NewParam->getDepth() == 0 && "unexpected template param depth");
1843 NewParam->setPosition(NewParam->getPosition() + Depth1IndexAdjustment);
1847 QualType transformFunctionProtoType(TypeLocBuilder &TLB,
1848 FunctionProtoTypeLoc TL,
1849 SmallVectorImpl<ParmVarDecl*> &Params,
1850 MultiLevelTemplateArgumentList &Args) {
1851 SmallVector<QualType, 4> ParamTypes;
1852 const FunctionProtoType *T = TL.getTypePtr();
1854 // -- The types of the function parameters are those of the constructor.
1855 for (auto *OldParam : TL.getParams()) {
1856 ParmVarDecl *NewParam = transformFunctionTypeParam(OldParam, Args);
1859 ParamTypes.push_back(NewParam->getType());
1860 Params.push_back(NewParam);
1863 // -- The return type is the class template specialization designated by
1864 // the template-name and template arguments corresponding to the
1865 // template parameters obtained from the class template.
1867 // We use the injected-class-name type of the primary template instead.
1868 // This has the convenient property that it is different from any type that
1869 // the user can write in a deduction-guide (because they cannot enter the
1870 // context of the template), so implicit deduction guides can never collide
1871 // with explicit ones.
1872 QualType ReturnType = DeducedType;
1873 TLB.pushTypeSpec(ReturnType).setNameLoc(Primary->getLocation());
1875 // Resolving a wording defect, we also inherit the variadicness of the
1877 FunctionProtoType::ExtProtoInfo EPI;
1878 EPI.Variadic = T->isVariadic();
1879 EPI.HasTrailingReturn = true;
1881 QualType Result = SemaRef.BuildFunctionType(
1882 ReturnType, ParamTypes, TL.getBeginLoc(), DeductionGuideName, EPI);
1883 if (Result.isNull())
1886 FunctionProtoTypeLoc NewTL = TLB.push<FunctionProtoTypeLoc>(Result);
1887 NewTL.setLocalRangeBegin(TL.getLocalRangeBegin());
1888 NewTL.setLParenLoc(TL.getLParenLoc());
1889 NewTL.setRParenLoc(TL.getRParenLoc());
1890 NewTL.setExceptionSpecRange(SourceRange());
1891 NewTL.setLocalRangeEnd(TL.getLocalRangeEnd());
1892 for (unsigned I = 0, E = NewTL.getNumParams(); I != E; ++I)
1893 NewTL.setParam(I, Params[I]);
1899 transformFunctionTypeParam(ParmVarDecl *OldParam,
1900 MultiLevelTemplateArgumentList &Args) {
1901 TypeSourceInfo *OldDI = OldParam->getTypeSourceInfo();
1902 TypeSourceInfo *NewDI;
1903 if (auto PackTL = OldDI->getTypeLoc().getAs<PackExpansionTypeLoc>()) {
1904 // Expand out the one and only element in each inner pack.
1905 Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, 0);
1907 SemaRef.SubstType(PackTL.getPatternLoc(), Args,
1908 OldParam->getLocation(), OldParam->getDeclName());
1909 if (!NewDI) return nullptr;
1911 SemaRef.CheckPackExpansion(NewDI, PackTL.getEllipsisLoc(),
1912 PackTL.getTypePtr()->getNumExpansions());
1914 NewDI = SemaRef.SubstType(OldDI, Args, OldParam->getLocation(),
1915 OldParam->getDeclName());
1919 // Extract the type. This (for instance) replaces references to typedef
1920 // members of the current instantiations with the definitions of those
1921 // typedefs, avoiding triggering instantiation of the deduced type during
1923 NewDI = ExtractTypeForDeductionGuide(SemaRef).transform(NewDI);
1925 // Resolving a wording defect, we also inherit default arguments from the
1927 ExprResult NewDefArg;
1928 if (OldParam->hasDefaultArg()) {
1929 NewDefArg = SemaRef.SubstExpr(OldParam->getDefaultArg(), Args);
1930 if (NewDefArg.isInvalid())
1934 ParmVarDecl *NewParam = ParmVarDecl::Create(SemaRef.Context, DC,
1935 OldParam->getInnerLocStart(),
1936 OldParam->getLocation(),
1937 OldParam->getIdentifier(),
1940 OldParam->getStorageClass(),
1942 NewParam->setScopeInfo(OldParam->getFunctionScopeDepth(),
1943 OldParam->getFunctionScopeIndex());
1944 SemaRef.CurrentInstantiationScope->InstantiatedLocal(OldParam, NewParam);
1948 NamedDecl *buildDeductionGuide(TemplateParameterList *TemplateParams,
1949 bool Explicit, TypeSourceInfo *TInfo,
1950 SourceLocation LocStart, SourceLocation Loc,
1951 SourceLocation LocEnd) {
1952 DeclarationNameInfo Name(DeductionGuideName, Loc);
1953 ArrayRef<ParmVarDecl *> Params =
1954 TInfo->getTypeLoc().castAs<FunctionProtoTypeLoc>().getParams();
1956 // Build the implicit deduction guide template.
1958 CXXDeductionGuideDecl::Create(SemaRef.Context, DC, LocStart, Explicit,
1959 Name, TInfo->getType(), TInfo, LocEnd);
1960 Guide->setImplicit();
1961 Guide->setParams(Params);
1963 for (auto *Param : Params)
1964 Param->setDeclContext(Guide);
1966 auto *GuideTemplate = FunctionTemplateDecl::Create(
1967 SemaRef.Context, DC, Loc, DeductionGuideName, TemplateParams, Guide);
1968 GuideTemplate->setImplicit();
1969 Guide->setDescribedFunctionTemplate(GuideTemplate);
1971 if (isa<CXXRecordDecl>(DC)) {
1972 Guide->setAccess(AS_public);
1973 GuideTemplate->setAccess(AS_public);
1976 DC->addDecl(GuideTemplate);
1977 return GuideTemplate;
1982 void Sema::DeclareImplicitDeductionGuides(TemplateDecl *Template,
1983 SourceLocation Loc) {
1984 DeclContext *DC = Template->getDeclContext();
1985 if (DC->isDependentContext())
1988 ConvertConstructorToDeductionGuideTransform Transform(
1989 *this, cast<ClassTemplateDecl>(Template));
1990 if (!isCompleteType(Loc, Transform.DeducedType))
1993 // Check whether we've already declared deduction guides for this template.
1994 // FIXME: Consider storing a flag on the template to indicate this.
1995 auto Existing = DC->lookup(Transform.DeductionGuideName);
1996 for (auto *D : Existing)
1997 if (D->isImplicit())
2000 // In case we were expanding a pack when we attempted to declare deduction
2001 // guides, turn off pack expansion for everything we're about to do.
2002 ArgumentPackSubstitutionIndexRAII SubstIndex(*this, -1);
2003 // Create a template instantiation record to track the "instantiation" of
2004 // constructors into deduction guides.
2005 // FIXME: Add a kind for this to give more meaningful diagnostics. But can
2006 // this substitution process actually fail?
2007 InstantiatingTemplate BuildingDeductionGuides(*this, Loc, Template);
2008 if (BuildingDeductionGuides.isInvalid())
2011 // Convert declared constructors into deduction guide templates.
2012 // FIXME: Skip constructors for which deduction must necessarily fail (those
2013 // for which some class template parameter without a default argument never
2014 // appears in a deduced context).
2015 bool AddedAny = false;
2016 for (NamedDecl *D : LookupConstructors(Transform.Primary)) {
2017 D = D->getUnderlyingDecl();
2018 if (D->isInvalidDecl() || D->isImplicit())
2020 D = cast<NamedDecl>(D->getCanonicalDecl());
2022 auto *FTD = dyn_cast<FunctionTemplateDecl>(D);
2024 dyn_cast_or_null<CXXConstructorDecl>(FTD ? FTD->getTemplatedDecl() : D);
2025 // Class-scope explicit specializations (MS extension) do not result in
2026 // deduction guides.
2027 if (!CD || (!FTD && CD->isFunctionTemplateSpecialization()))
2030 Transform.transformConstructor(FTD, CD);
2034 // C++17 [over.match.class.deduct]
2035 // -- If C is not defined or does not declare any constructors, an
2036 // additional function template derived as above from a hypothetical
2039 Transform.buildSimpleDeductionGuide(None);
2041 // -- An additional function template derived as above from a hypothetical
2042 // constructor C(C), called the copy deduction candidate.
2043 cast<CXXDeductionGuideDecl>(
2044 cast<FunctionTemplateDecl>(
2045 Transform.buildSimpleDeductionGuide(Transform.DeducedType))
2046 ->getTemplatedDecl())
2047 ->setIsCopyDeductionCandidate();
2050 /// Diagnose the presence of a default template argument on a
2051 /// template parameter, which is ill-formed in certain contexts.
2053 /// \returns true if the default template argument should be dropped.
2054 static bool DiagnoseDefaultTemplateArgument(Sema &S,
2055 Sema::TemplateParamListContext TPC,
2056 SourceLocation ParamLoc,
2057 SourceRange DefArgRange) {
2059 case Sema::TPC_ClassTemplate:
2060 case Sema::TPC_VarTemplate:
2061 case Sema::TPC_TypeAliasTemplate:
2064 case Sema::TPC_FunctionTemplate:
2065 case Sema::TPC_FriendFunctionTemplateDefinition:
2066 // C++ [temp.param]p9:
2067 // A default template-argument shall not be specified in a
2068 // function template declaration or a function template
2070 // If a friend function template declaration specifies a default
2071 // template-argument, that declaration shall be a definition and shall be
2072 // the only declaration of the function template in the translation unit.
2073 // (C++98/03 doesn't have this wording; see DR226).
2074 S.Diag(ParamLoc, S.getLangOpts().CPlusPlus11 ?
2075 diag::warn_cxx98_compat_template_parameter_default_in_function_template
2076 : diag::ext_template_parameter_default_in_function_template)
2080 case Sema::TPC_ClassTemplateMember:
2081 // C++0x [temp.param]p9:
2082 // A default template-argument shall not be specified in the
2083 // template-parameter-lists of the definition of a member of a
2084 // class template that appears outside of the member's class.
2085 S.Diag(ParamLoc, diag::err_template_parameter_default_template_member)
2089 case Sema::TPC_FriendClassTemplate:
2090 case Sema::TPC_FriendFunctionTemplate:
2091 // C++ [temp.param]p9:
2092 // A default template-argument shall not be specified in a
2093 // friend template declaration.
2094 S.Diag(ParamLoc, diag::err_template_parameter_default_friend_template)
2098 // FIXME: C++0x [temp.param]p9 allows default template-arguments
2099 // for friend function templates if there is only a single
2100 // declaration (and it is a definition). Strange!
2103 llvm_unreachable("Invalid TemplateParamListContext!");
2106 /// Check for unexpanded parameter packs within the template parameters
2107 /// of a template template parameter, recursively.
2108 static bool DiagnoseUnexpandedParameterPacks(Sema &S,
2109 TemplateTemplateParmDecl *TTP) {
2110 // A template template parameter which is a parameter pack is also a pack
2112 if (TTP->isParameterPack())
2115 TemplateParameterList *Params = TTP->getTemplateParameters();
2116 for (unsigned I = 0, N = Params->size(); I != N; ++I) {
2117 NamedDecl *P = Params->getParam(I);
2118 if (NonTypeTemplateParmDecl *NTTP = dyn_cast<NonTypeTemplateParmDecl>(P)) {
2119 if (!NTTP->isParameterPack() &&
2120 S.DiagnoseUnexpandedParameterPack(NTTP->getLocation(),
2121 NTTP->getTypeSourceInfo(),
2122 Sema::UPPC_NonTypeTemplateParameterType))
2128 if (TemplateTemplateParmDecl *InnerTTP
2129 = dyn_cast<TemplateTemplateParmDecl>(P))
2130 if (DiagnoseUnexpandedParameterPacks(S, InnerTTP))
2137 /// Checks the validity of a template parameter list, possibly
2138 /// considering the template parameter list from a previous
2141 /// If an "old" template parameter list is provided, it must be
2142 /// equivalent (per TemplateParameterListsAreEqual) to the "new"
2143 /// template parameter list.
2145 /// \param NewParams Template parameter list for a new template
2146 /// declaration. This template parameter list will be updated with any
2147 /// default arguments that are carried through from the previous
2148 /// template parameter list.
2150 /// \param OldParams If provided, template parameter list from a
2151 /// previous declaration of the same template. Default template
2152 /// arguments will be merged from the old template parameter list to
2153 /// the new template parameter list.
2155 /// \param TPC Describes the context in which we are checking the given
2156 /// template parameter list.
2158 /// \param SkipBody If we might have already made a prior merged definition
2159 /// of this template visible, the corresponding body-skipping information.
2160 /// Default argument redefinition is not an error when skipping such a body,
2161 /// because (under the ODR) we can assume the default arguments are the same
2162 /// as the prior merged definition.
2164 /// \returns true if an error occurred, false otherwise.
2165 bool Sema::CheckTemplateParameterList(TemplateParameterList *NewParams,
2166 TemplateParameterList *OldParams,
2167 TemplateParamListContext TPC,
2168 SkipBodyInfo *SkipBody) {
2169 bool Invalid = false;
2171 // C++ [temp.param]p10:
2172 // The set of default template-arguments available for use with a
2173 // template declaration or definition is obtained by merging the
2174 // default arguments from the definition (if in scope) and all
2175 // declarations in scope in the same way default function
2176 // arguments are (8.3.6).
2177 bool SawDefaultArgument = false;
2178 SourceLocation PreviousDefaultArgLoc;
2180 // Dummy initialization to avoid warnings.
2181 TemplateParameterList::iterator OldParam = NewParams->end();
2183 OldParam = OldParams->begin();
2185 bool RemoveDefaultArguments = false;
2186 for (TemplateParameterList::iterator NewParam = NewParams->begin(),
2187 NewParamEnd = NewParams->end();
2188 NewParam != NewParamEnd; ++NewParam) {
2189 // Variables used to diagnose redundant default arguments
2190 bool RedundantDefaultArg = false;
2191 SourceLocation OldDefaultLoc;
2192 SourceLocation NewDefaultLoc;
2194 // Variable used to diagnose missing default arguments
2195 bool MissingDefaultArg = false;
2197 // Variable used to diagnose non-final parameter packs
2198 bool SawParameterPack = false;
2200 if (TemplateTypeParmDecl *NewTypeParm
2201 = dyn_cast<TemplateTypeParmDecl>(*NewParam)) {
2202 // Check the presence of a default argument here.
2203 if (NewTypeParm->hasDefaultArgument() &&
2204 DiagnoseDefaultTemplateArgument(*this, TPC,
2205 NewTypeParm->getLocation(),
2206 NewTypeParm->getDefaultArgumentInfo()->getTypeLoc()
2208 NewTypeParm->removeDefaultArgument();
2210 // Merge default arguments for template type parameters.
2211 TemplateTypeParmDecl *OldTypeParm
2212 = OldParams? cast<TemplateTypeParmDecl>(*OldParam) : nullptr;
2213 if (NewTypeParm->isParameterPack()) {
2214 assert(!NewTypeParm->hasDefaultArgument() &&
2215 "Parameter packs can't have a default argument!");
2216 SawParameterPack = true;
2217 } else if (OldTypeParm && hasVisibleDefaultArgument(OldTypeParm) &&
2218 NewTypeParm->hasDefaultArgument() &&
2219 (!SkipBody || !SkipBody->ShouldSkip)) {
2220 OldDefaultLoc = OldTypeParm->getDefaultArgumentLoc();
2221 NewDefaultLoc = NewTypeParm->getDefaultArgumentLoc();
2222 SawDefaultArgument = true;
2223 RedundantDefaultArg = true;
2224 PreviousDefaultArgLoc = NewDefaultLoc;
2225 } else if (OldTypeParm && OldTypeParm->hasDefaultArgument()) {
2226 // Merge the default argument from the old declaration to the
2228 NewTypeParm->setInheritedDefaultArgument(Context, OldTypeParm);
2229 PreviousDefaultArgLoc = OldTypeParm->getDefaultArgumentLoc();
2230 } else if (NewTypeParm->hasDefaultArgument()) {
2231 SawDefaultArgument = true;
2232 PreviousDefaultArgLoc = NewTypeParm->getDefaultArgumentLoc();
2233 } else if (SawDefaultArgument)
2234 MissingDefaultArg = true;
2235 } else if (NonTypeTemplateParmDecl *NewNonTypeParm
2236 = dyn_cast<NonTypeTemplateParmDecl>(*NewParam)) {
2237 // Check for unexpanded parameter packs.
2238 if (!NewNonTypeParm->isParameterPack() &&
2239 DiagnoseUnexpandedParameterPack(NewNonTypeParm->getLocation(),
2240 NewNonTypeParm->getTypeSourceInfo(),
2241 UPPC_NonTypeTemplateParameterType)) {
2246 // Check the presence of a default argument here.
2247 if (NewNonTypeParm->hasDefaultArgument() &&
2248 DiagnoseDefaultTemplateArgument(*this, TPC,
2249 NewNonTypeParm->getLocation(),
2250 NewNonTypeParm->getDefaultArgument()->getSourceRange())) {
2251 NewNonTypeParm->removeDefaultArgument();
2254 // Merge default arguments for non-type template parameters
2255 NonTypeTemplateParmDecl *OldNonTypeParm
2256 = OldParams? cast<NonTypeTemplateParmDecl>(*OldParam) : nullptr;
2257 if (NewNonTypeParm->isParameterPack()) {
2258 assert(!NewNonTypeParm->hasDefaultArgument() &&
2259 "Parameter packs can't have a default argument!");
2260 if (!NewNonTypeParm->isPackExpansion())
2261 SawParameterPack = true;
2262 } else if (OldNonTypeParm && hasVisibleDefaultArgument(OldNonTypeParm) &&
2263 NewNonTypeParm->hasDefaultArgument() &&
2264 (!SkipBody || !SkipBody->ShouldSkip)) {
2265 OldDefaultLoc = OldNonTypeParm->getDefaultArgumentLoc();
2266 NewDefaultLoc = NewNonTypeParm->getDefaultArgumentLoc();
2267 SawDefaultArgument = true;
2268 RedundantDefaultArg = true;
2269 PreviousDefaultArgLoc = NewDefaultLoc;
2270 } else if (OldNonTypeParm && OldNonTypeParm->hasDefaultArgument()) {
2271 // Merge the default argument from the old declaration to the
2273 NewNonTypeParm->setInheritedDefaultArgument(Context, OldNonTypeParm);
2274 PreviousDefaultArgLoc = OldNonTypeParm->getDefaultArgumentLoc();
2275 } else if (NewNonTypeParm->hasDefaultArgument()) {
2276 SawDefaultArgument = true;
2277 PreviousDefaultArgLoc = NewNonTypeParm->getDefaultArgumentLoc();
2278 } else if (SawDefaultArgument)
2279 MissingDefaultArg = true;
2281 TemplateTemplateParmDecl *NewTemplateParm
2282 = cast<TemplateTemplateParmDecl>(*NewParam);
2284 // Check for unexpanded parameter packs, recursively.
2285 if (::DiagnoseUnexpandedParameterPacks(*this, NewTemplateParm)) {
2290 // Check the presence of a default argument here.
2291 if (NewTemplateParm->hasDefaultArgument() &&
2292 DiagnoseDefaultTemplateArgument(*this, TPC,
2293 NewTemplateParm->getLocation(),
2294 NewTemplateParm->getDefaultArgument().getSourceRange()))
2295 NewTemplateParm->removeDefaultArgument();
2297 // Merge default arguments for template template parameters
2298 TemplateTemplateParmDecl *OldTemplateParm
2299 = OldParams? cast<TemplateTemplateParmDecl>(*OldParam) : nullptr;
2300 if (NewTemplateParm->isParameterPack()) {
2301 assert(!NewTemplateParm->hasDefaultArgument() &&
2302 "Parameter packs can't have a default argument!");
2303 if (!NewTemplateParm->isPackExpansion())
2304 SawParameterPack = true;
2305 } else if (OldTemplateParm &&
2306 hasVisibleDefaultArgument(OldTemplateParm) &&
2307 NewTemplateParm->hasDefaultArgument() &&
2308 (!SkipBody || !SkipBody->ShouldSkip)) {
2309 OldDefaultLoc = OldTemplateParm->getDefaultArgument().getLocation();
2310 NewDefaultLoc = NewTemplateParm->getDefaultArgument().getLocation();
2311 SawDefaultArgument = true;
2312 RedundantDefaultArg = true;
2313 PreviousDefaultArgLoc = NewDefaultLoc;
2314 } else if (OldTemplateParm && OldTemplateParm->hasDefaultArgument()) {
2315 // Merge the default argument from the old declaration to the
2317 NewTemplateParm->setInheritedDefaultArgument(Context, OldTemplateParm);
2318 PreviousDefaultArgLoc
2319 = OldTemplateParm->getDefaultArgument().getLocation();
2320 } else if (NewTemplateParm->hasDefaultArgument()) {
2321 SawDefaultArgument = true;
2322 PreviousDefaultArgLoc
2323 = NewTemplateParm->getDefaultArgument().getLocation();
2324 } else if (SawDefaultArgument)
2325 MissingDefaultArg = true;
2328 // C++11 [temp.param]p11:
2329 // If a template parameter of a primary class template or alias template
2330 // is a template parameter pack, it shall be the last template parameter.
2331 if (SawParameterPack && (NewParam + 1) != NewParamEnd &&
2332 (TPC == TPC_ClassTemplate || TPC == TPC_VarTemplate ||
2333 TPC == TPC_TypeAliasTemplate)) {
2334 Diag((*NewParam)->getLocation(),
2335 diag::err_template_param_pack_must_be_last_template_parameter);
2339 if (RedundantDefaultArg) {
2340 // C++ [temp.param]p12:
2341 // A template-parameter shall not be given default arguments
2342 // by two different declarations in the same scope.
2343 Diag(NewDefaultLoc, diag::err_template_param_default_arg_redefinition);
2344 Diag(OldDefaultLoc, diag::note_template_param_prev_default_arg);
2346 } else if (MissingDefaultArg && TPC != TPC_FunctionTemplate) {
2347 // C++ [temp.param]p11:
2348 // If a template-parameter of a class template has a default
2349 // template-argument, each subsequent template-parameter shall either
2350 // have a default template-argument supplied or be a template parameter
2352 Diag((*NewParam)->getLocation(),
2353 diag::err_template_param_default_arg_missing);
2354 Diag(PreviousDefaultArgLoc, diag::note_template_param_prev_default_arg);
2356 RemoveDefaultArguments = true;
2359 // If we have an old template parameter list that we're merging
2360 // in, move on to the next parameter.
2365 // We were missing some default arguments at the end of the list, so remove
2366 // all of the default arguments.
2367 if (RemoveDefaultArguments) {
2368 for (TemplateParameterList::iterator NewParam = NewParams->begin(),
2369 NewParamEnd = NewParams->end();
2370 NewParam != NewParamEnd; ++NewParam) {
2371 if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(*NewParam))
2372 TTP->removeDefaultArgument();
2373 else if (NonTypeTemplateParmDecl *NTTP
2374 = dyn_cast<NonTypeTemplateParmDecl>(*NewParam))
2375 NTTP->removeDefaultArgument();
2377 cast<TemplateTemplateParmDecl>(*NewParam)->removeDefaultArgument();
2386 /// A class which looks for a use of a certain level of template
2388 struct DependencyChecker : RecursiveASTVisitor<DependencyChecker> {
2389 typedef RecursiveASTVisitor<DependencyChecker> super;
2393 // Whether we're looking for a use of a template parameter that makes the
2394 // overall construct type-dependent / a dependent type. This is strictly
2395 // best-effort for now; we may fail to match at all for a dependent type
2396 // in some cases if this is set.
2397 bool IgnoreNonTypeDependent;
2400 SourceLocation MatchLoc;
2402 DependencyChecker(unsigned Depth, bool IgnoreNonTypeDependent)
2403 : Depth(Depth), IgnoreNonTypeDependent(IgnoreNonTypeDependent),
2406 DependencyChecker(TemplateParameterList *Params, bool IgnoreNonTypeDependent)
2407 : IgnoreNonTypeDependent(IgnoreNonTypeDependent), Match(false) {
2408 NamedDecl *ND = Params->getParam(0);
2409 if (TemplateTypeParmDecl *PD = dyn_cast<TemplateTypeParmDecl>(ND)) {
2410 Depth = PD->getDepth();
2411 } else if (NonTypeTemplateParmDecl *PD =
2412 dyn_cast<NonTypeTemplateParmDecl>(ND)) {
2413 Depth = PD->getDepth();
2415 Depth = cast<TemplateTemplateParmDecl>(ND)->getDepth();
2419 bool Matches(unsigned ParmDepth, SourceLocation Loc = SourceLocation()) {
2420 if (ParmDepth >= Depth) {
2428 bool TraverseStmt(Stmt *S, DataRecursionQueue *Q = nullptr) {
2429 // Prune out non-type-dependent expressions if requested. This can
2430 // sometimes result in us failing to find a template parameter reference
2431 // (if a value-dependent expression creates a dependent type), but this
2432 // mode is best-effort only.
2433 if (auto *E = dyn_cast_or_null<Expr>(S))
2434 if (IgnoreNonTypeDependent && !E->isTypeDependent())
2436 return super::TraverseStmt(S, Q);
2439 bool TraverseTypeLoc(TypeLoc TL) {
2440 if (IgnoreNonTypeDependent && !TL.isNull() &&
2441 !TL.getType()->isDependentType())
2443 return super::TraverseTypeLoc(TL);
2446 bool VisitTemplateTypeParmTypeLoc(TemplateTypeParmTypeLoc TL) {
2447 return !Matches(TL.getTypePtr()->getDepth(), TL.getNameLoc());
2450 bool VisitTemplateTypeParmType(const TemplateTypeParmType *T) {
2451 // For a best-effort search, keep looking until we find a location.
2452 return IgnoreNonTypeDependent || !Matches(T->getDepth());
2455 bool TraverseTemplateName(TemplateName N) {
2456 if (TemplateTemplateParmDecl *PD =
2457 dyn_cast_or_null<TemplateTemplateParmDecl>(N.getAsTemplateDecl()))
2458 if (Matches(PD->getDepth()))
2460 return super::TraverseTemplateName(N);
2463 bool VisitDeclRefExpr(DeclRefExpr *E) {
2464 if (NonTypeTemplateParmDecl *PD =
2465 dyn_cast<NonTypeTemplateParmDecl>(E->getDecl()))
2466 if (Matches(PD->getDepth(), E->getExprLoc()))
2468 return super::VisitDeclRefExpr(E);
2471 bool VisitSubstTemplateTypeParmType(const SubstTemplateTypeParmType *T) {
2472 return TraverseType(T->getReplacementType());
2476 VisitSubstTemplateTypeParmPackType(const SubstTemplateTypeParmPackType *T) {
2477 return TraverseTemplateArgument(T->getArgumentPack());
2480 bool TraverseInjectedClassNameType(const InjectedClassNameType *T) {
2481 return TraverseType(T->getInjectedSpecializationType());
2484 } // end anonymous namespace
2486 /// Determines whether a given type depends on the given parameter
2489 DependsOnTemplateParameters(QualType T, TemplateParameterList *Params) {
2490 DependencyChecker Checker(Params, /*IgnoreNonTypeDependent*/false);
2491 Checker.TraverseType(T);
2492 return Checker.Match;
2495 // Find the source range corresponding to the named type in the given
2496 // nested-name-specifier, if any.
2497 static SourceRange getRangeOfTypeInNestedNameSpecifier(ASTContext &Context,
2499 const CXXScopeSpec &SS) {
2500 NestedNameSpecifierLoc NNSLoc(SS.getScopeRep(), SS.location_data());
2501 while (NestedNameSpecifier *NNS = NNSLoc.getNestedNameSpecifier()) {
2502 if (const Type *CurType = NNS->getAsType()) {
2503 if (Context.hasSameUnqualifiedType(T, QualType(CurType, 0)))
2504 return NNSLoc.getTypeLoc().getSourceRange();
2508 NNSLoc = NNSLoc.getPrefix();
2511 return SourceRange();
2514 /// Match the given template parameter lists to the given scope
2515 /// specifier, returning the template parameter list that applies to the
2518 /// \param DeclStartLoc the start of the declaration that has a scope
2519 /// specifier or a template parameter list.
2521 /// \param DeclLoc The location of the declaration itself.
2523 /// \param SS the scope specifier that will be matched to the given template
2524 /// parameter lists. This scope specifier precedes a qualified name that is
2527 /// \param TemplateId The template-id following the scope specifier, if there
2528 /// is one. Used to check for a missing 'template<>'.
2530 /// \param ParamLists the template parameter lists, from the outermost to the
2531 /// innermost template parameter lists.
2533 /// \param IsFriend Whether to apply the slightly different rules for
2534 /// matching template parameters to scope specifiers in friend
2537 /// \param IsMemberSpecialization will be set true if the scope specifier
2538 /// denotes a fully-specialized type, and therefore this is a declaration of
2539 /// a member specialization.
2541 /// \returns the template parameter list, if any, that corresponds to the
2542 /// name that is preceded by the scope specifier @p SS. This template
2543 /// parameter list may have template parameters (if we're declaring a
2544 /// template) or may have no template parameters (if we're declaring a
2545 /// template specialization), or may be NULL (if what we're declaring isn't
2546 /// itself a template).
2547 TemplateParameterList *Sema::MatchTemplateParametersToScopeSpecifier(
2548 SourceLocation DeclStartLoc, SourceLocation DeclLoc, const CXXScopeSpec &SS,
2549 TemplateIdAnnotation *TemplateId,
2550 ArrayRef<TemplateParameterList *> ParamLists, bool IsFriend,
2551 bool &IsMemberSpecialization, bool &Invalid) {
2552 IsMemberSpecialization = false;
2555 // The sequence of nested types to which we will match up the template
2556 // parameter lists. We first build this list by starting with the type named
2557 // by the nested-name-specifier and walking out until we run out of types.
2558 SmallVector<QualType, 4> NestedTypes;
2560 if (SS.getScopeRep()) {
2561 if (CXXRecordDecl *Record
2562 = dyn_cast_or_null<CXXRecordDecl>(computeDeclContext(SS, true)))
2563 T = Context.getTypeDeclType(Record);
2565 T = QualType(SS.getScopeRep()->getAsType(), 0);
2568 // If we found an explicit specialization that prevents us from needing
2569 // 'template<>' headers, this will be set to the location of that
2570 // explicit specialization.
2571 SourceLocation ExplicitSpecLoc;
2573 while (!T.isNull()) {
2574 NestedTypes.push_back(T);
2576 // Retrieve the parent of a record type.
2577 if (CXXRecordDecl *Record = T->getAsCXXRecordDecl()) {
2578 // If this type is an explicit specialization, we're done.
2579 if (ClassTemplateSpecializationDecl *Spec
2580 = dyn_cast<ClassTemplateSpecializationDecl>(Record)) {
2581 if (!isa<ClassTemplatePartialSpecializationDecl>(Spec) &&
2582 Spec->getSpecializationKind() == TSK_ExplicitSpecialization) {
2583 ExplicitSpecLoc = Spec->getLocation();
2586 } else if (Record->getTemplateSpecializationKind()
2587 == TSK_ExplicitSpecialization) {
2588 ExplicitSpecLoc = Record->getLocation();
2592 if (TypeDecl *Parent = dyn_cast<TypeDecl>(Record->getParent()))
2593 T = Context.getTypeDeclType(Parent);
2599 if (const TemplateSpecializationType *TST
2600 = T->getAs<TemplateSpecializationType>()) {
2601 if (TemplateDecl *Template = TST->getTemplateName().getAsTemplateDecl()) {
2602 if (TypeDecl *Parent = dyn_cast<TypeDecl>(Template->getDeclContext()))
2603 T = Context.getTypeDeclType(Parent);
2610 // Look one step prior in a dependent template specialization type.
2611 if (const DependentTemplateSpecializationType *DependentTST
2612 = T->getAs<DependentTemplateSpecializationType>()) {
2613 if (NestedNameSpecifier *NNS = DependentTST->getQualifier())
2614 T = QualType(NNS->getAsType(), 0);
2620 // Look one step prior in a dependent name type.
2621 if (const DependentNameType *DependentName = T->getAs<DependentNameType>()){
2622 if (NestedNameSpecifier *NNS = DependentName->getQualifier())
2623 T = QualType(NNS->getAsType(), 0);
2629 // Retrieve the parent of an enumeration type.
2630 if (const EnumType *EnumT = T->getAs<EnumType>()) {
2631 // FIXME: Forward-declared enums require a TSK_ExplicitSpecialization
2633 EnumDecl *Enum = EnumT->getDecl();
2635 // Get to the parent type.
2636 if (TypeDecl *Parent = dyn_cast<TypeDecl>(Enum->getParent()))
2637 T = Context.getTypeDeclType(Parent);
2645 // Reverse the nested types list, since we want to traverse from the outermost
2646 // to the innermost while checking template-parameter-lists.
2647 std::reverse(NestedTypes.begin(), NestedTypes.end());
2649 // C++0x [temp.expl.spec]p17:
2650 // A member or a member template may be nested within many
2651 // enclosing class templates. In an explicit specialization for
2652 // such a member, the member declaration shall be preceded by a
2653 // template<> for each enclosing class template that is
2654 // explicitly specialized.
2655 bool SawNonEmptyTemplateParameterList = false;
2657 auto CheckExplicitSpecialization = [&](SourceRange Range, bool Recovery) {
2658 if (SawNonEmptyTemplateParameterList) {
2659 Diag(DeclLoc, diag::err_specialize_member_of_template)
2660 << !Recovery << Range;
2662 IsMemberSpecialization = false;
2669 auto DiagnoseMissingExplicitSpecialization = [&] (SourceRange Range) {
2670 // Check that we can have an explicit specialization here.
2671 if (CheckExplicitSpecialization(Range, true))
2674 // We don't have a template header, but we should.
2675 SourceLocation ExpectedTemplateLoc;
2676 if (!ParamLists.empty())
2677 ExpectedTemplateLoc = ParamLists[0]->getTemplateLoc();
2679 ExpectedTemplateLoc = DeclStartLoc;
2681 Diag(DeclLoc, diag::err_template_spec_needs_header)
2683 << FixItHint::CreateInsertion(ExpectedTemplateLoc, "template<> ");
2687 unsigned ParamIdx = 0;
2688 for (unsigned TypeIdx = 0, NumTypes = NestedTypes.size(); TypeIdx != NumTypes;
2690 T = NestedTypes[TypeIdx];
2692 // Whether we expect a 'template<>' header.
2693 bool NeedEmptyTemplateHeader = false;
2695 // Whether we expect a template header with parameters.
2696 bool NeedNonemptyTemplateHeader = false;
2698 // For a dependent type, the set of template parameters that we
2700 TemplateParameterList *ExpectedTemplateParams = nullptr;
2702 // C++0x [temp.expl.spec]p15:
2703 // A member or a member template may be nested within many enclosing
2704 // class templates. In an explicit specialization for such a member, the
2705 // member declaration shall be preceded by a template<> for each
2706 // enclosing class template that is explicitly specialized.
2707 if (CXXRecordDecl *Record = T->getAsCXXRecordDecl()) {
2708 if (ClassTemplatePartialSpecializationDecl *Partial
2709 = dyn_cast<ClassTemplatePartialSpecializationDecl>(Record)) {
2710 ExpectedTemplateParams = Partial->getTemplateParameters();
2711 NeedNonemptyTemplateHeader = true;
2712 } else if (Record->isDependentType()) {
2713 if (Record->getDescribedClassTemplate()) {
2714 ExpectedTemplateParams = Record->getDescribedClassTemplate()
2715 ->getTemplateParameters();
2716 NeedNonemptyTemplateHeader = true;
2718 } else if (ClassTemplateSpecializationDecl *Spec
2719 = dyn_cast<ClassTemplateSpecializationDecl>(Record)) {
2720 // C++0x [temp.expl.spec]p4:
2721 // Members of an explicitly specialized class template are defined
2722 // in the same manner as members of normal classes, and not using
2723 // the template<> syntax.
2724 if (Spec->getSpecializationKind() != TSK_ExplicitSpecialization)
2725 NeedEmptyTemplateHeader = true;
2728 } else if (Record->getTemplateSpecializationKind()) {
2729 if (Record->getTemplateSpecializationKind()
2730 != TSK_ExplicitSpecialization &&
2731 TypeIdx == NumTypes - 1)
2732 IsMemberSpecialization = true;
2736 } else if (const TemplateSpecializationType *TST
2737 = T->getAs<TemplateSpecializationType>()) {
2738 if (TemplateDecl *Template = TST->getTemplateName().getAsTemplateDecl()) {
2739 ExpectedTemplateParams = Template->getTemplateParameters();
2740 NeedNonemptyTemplateHeader = true;
2742 } else if (T->getAs<DependentTemplateSpecializationType>()) {
2743 // FIXME: We actually could/should check the template arguments here
2744 // against the corresponding template parameter list.
2745 NeedNonemptyTemplateHeader = false;
2748 // C++ [temp.expl.spec]p16:
2749 // In an explicit specialization declaration for a member of a class
2750 // template or a member template that ap- pears in namespace scope, the
2751 // member template and some of its enclosing class templates may remain
2752 // unspecialized, except that the declaration shall not explicitly
2753 // specialize a class member template if its en- closing class templates
2754 // are not explicitly specialized as well.
2755 if (ParamIdx < ParamLists.size()) {
2756 if (ParamLists[ParamIdx]->size() == 0) {
2757 if (CheckExplicitSpecialization(ParamLists[ParamIdx]->getSourceRange(),
2761 SawNonEmptyTemplateParameterList = true;
2764 if (NeedEmptyTemplateHeader) {
2765 // If we're on the last of the types, and we need a 'template<>' header
2766 // here, then it's a member specialization.
2767 if (TypeIdx == NumTypes - 1)
2768 IsMemberSpecialization = true;
2770 if (ParamIdx < ParamLists.size()) {
2771 if (ParamLists[ParamIdx]->size() > 0) {
2772 // The header has template parameters when it shouldn't. Complain.
2773 Diag(ParamLists[ParamIdx]->getTemplateLoc(),
2774 diag::err_template_param_list_matches_nontemplate)
2776 << SourceRange(ParamLists[ParamIdx]->getLAngleLoc(),
2777 ParamLists[ParamIdx]->getRAngleLoc())
2778 << getRangeOfTypeInNestedNameSpecifier(Context, T, SS);
2783 // Consume this template header.
2789 if (DiagnoseMissingExplicitSpecialization(
2790 getRangeOfTypeInNestedNameSpecifier(Context, T, SS)))
2796 if (NeedNonemptyTemplateHeader) {
2797 // In friend declarations we can have template-ids which don't
2798 // depend on the corresponding template parameter lists. But
2799 // assume that empty parameter lists are supposed to match this
2801 if (IsFriend && T->isDependentType()) {
2802 if (ParamIdx < ParamLists.size() &&
2803 DependsOnTemplateParameters(T, ParamLists[ParamIdx]))
2804 ExpectedTemplateParams = nullptr;
2809 if (ParamIdx < ParamLists.size()) {
2810 // Check the template parameter list, if we can.
2811 if (ExpectedTemplateParams &&
2812 !TemplateParameterListsAreEqual(ParamLists[ParamIdx],
2813 ExpectedTemplateParams,
2814 true, TPL_TemplateMatch))
2818 CheckTemplateParameterList(ParamLists[ParamIdx], nullptr,
2819 TPC_ClassTemplateMember))
2826 Diag(DeclLoc, diag::err_template_spec_needs_template_parameters)
2828 << getRangeOfTypeInNestedNameSpecifier(Context, T, SS);
2834 // If there were at least as many template-ids as there were template
2835 // parameter lists, then there are no template parameter lists remaining for
2836 // the declaration itself.
2837 if (ParamIdx >= ParamLists.size()) {
2838 if (TemplateId && !IsFriend) {
2839 // We don't have a template header for the declaration itself, but we
2841 DiagnoseMissingExplicitSpecialization(SourceRange(TemplateId->LAngleLoc,
2842 TemplateId->RAngleLoc));
2844 // Fabricate an empty template parameter list for the invented header.
2845 return TemplateParameterList::Create(Context, SourceLocation(),
2846 SourceLocation(), None,
2847 SourceLocation(), nullptr);
2853 // If there were too many template parameter lists, complain about that now.
2854 if (ParamIdx < ParamLists.size() - 1) {
2855 bool HasAnyExplicitSpecHeader = false;
2856 bool AllExplicitSpecHeaders = true;
2857 for (unsigned I = ParamIdx, E = ParamLists.size() - 1; I != E; ++I) {
2858 if (ParamLists[I]->size() == 0)
2859 HasAnyExplicitSpecHeader = true;
2861 AllExplicitSpecHeaders = false;
2864 Diag(ParamLists[ParamIdx]->getTemplateLoc(),
2865 AllExplicitSpecHeaders ? diag::warn_template_spec_extra_headers
2866 : diag::err_template_spec_extra_headers)
2867 << SourceRange(ParamLists[ParamIdx]->getTemplateLoc(),
2868 ParamLists[ParamLists.size() - 2]->getRAngleLoc());
2870 // If there was a specialization somewhere, such that 'template<>' is
2871 // not required, and there were any 'template<>' headers, note where the
2872 // specialization occurred.
2873 if (ExplicitSpecLoc.isValid() && HasAnyExplicitSpecHeader)
2874 Diag(ExplicitSpecLoc,
2875 diag::note_explicit_template_spec_does_not_need_header)
2876 << NestedTypes.back();
2878 // We have a template parameter list with no corresponding scope, which
2879 // means that the resulting template declaration can't be instantiated
2880 // properly (we'll end up with dependent nodes when we shouldn't).
2881 if (!AllExplicitSpecHeaders)
2885 // C++ [temp.expl.spec]p16:
2886 // In an explicit specialization declaration for a member of a class
2887 // template or a member template that ap- pears in namespace scope, the
2888 // member template and some of its enclosing class templates may remain
2889 // unspecialized, except that the declaration shall not explicitly
2890 // specialize a class member template if its en- closing class templates
2891 // are not explicitly specialized as well.
2892 if (ParamLists.back()->size() == 0 &&
2893 CheckExplicitSpecialization(ParamLists[ParamIdx]->getSourceRange(),
2897 // Return the last template parameter list, which corresponds to the
2898 // entity being declared.
2899 return ParamLists.back();
2902 void Sema::NoteAllFoundTemplates(TemplateName Name) {
2903 if (TemplateDecl *Template = Name.getAsTemplateDecl()) {
2904 Diag(Template->getLocation(), diag::note_template_declared_here)
2905 << (isa<FunctionTemplateDecl>(Template)
2907 : isa<ClassTemplateDecl>(Template)
2909 : isa<VarTemplateDecl>(Template)
2911 : isa<TypeAliasTemplateDecl>(Template) ? 3 : 4)
2912 << Template->getDeclName();
2916 if (OverloadedTemplateStorage *OST = Name.getAsOverloadedTemplate()) {
2917 for (OverloadedTemplateStorage::iterator I = OST->begin(),
2920 Diag((*I)->getLocation(), diag::note_template_declared_here)
2921 << 0 << (*I)->getDeclName();
2928 checkBuiltinTemplateIdType(Sema &SemaRef, BuiltinTemplateDecl *BTD,
2929 const SmallVectorImpl<TemplateArgument> &Converted,
2930 SourceLocation TemplateLoc,
2931 TemplateArgumentListInfo &TemplateArgs) {
2932 ASTContext &Context = SemaRef.getASTContext();
2933 switch (BTD->getBuiltinTemplateKind()) {
2934 case BTK__make_integer_seq: {
2935 // Specializations of __make_integer_seq<S, T, N> are treated like
2936 // S<T, 0, ..., N-1>.
2938 // C++14 [inteseq.intseq]p1:
2939 // T shall be an integer type.
2940 if (!Converted[1].getAsType()->isIntegralType(Context)) {
2941 SemaRef.Diag(TemplateArgs[1].getLocation(),
2942 diag::err_integer_sequence_integral_element_type);
2946 // C++14 [inteseq.make]p1:
2947 // If N is negative the program is ill-formed.
2948 TemplateArgument NumArgsArg = Converted[2];
2949 llvm::APSInt NumArgs = NumArgsArg.getAsIntegral();
2951 SemaRef.Diag(TemplateArgs[2].getLocation(),
2952 diag::err_integer_sequence_negative_length);
2956 QualType ArgTy = NumArgsArg.getIntegralType();
2957 TemplateArgumentListInfo SyntheticTemplateArgs;
2958 // The type argument gets reused as the first template argument in the
2959 // synthetic template argument list.
2960 SyntheticTemplateArgs.addArgument(TemplateArgs[1]);
2961 // Expand N into 0 ... N-1.
2962 for (llvm::APSInt I(NumArgs.getBitWidth(), NumArgs.isUnsigned());
2964 TemplateArgument TA(Context, I, ArgTy);
2965 SyntheticTemplateArgs.addArgument(SemaRef.getTrivialTemplateArgumentLoc(
2966 TA, ArgTy, TemplateArgs[2].getLocation()));
2968 // The first template argument will be reused as the template decl that
2969 // our synthetic template arguments will be applied to.
2970 return SemaRef.CheckTemplateIdType(Converted[0].getAsTemplate(),
2971 TemplateLoc, SyntheticTemplateArgs);
2974 case BTK__type_pack_element:
2975 // Specializations of
2976 // __type_pack_element<Index, T_1, ..., T_N>
2977 // are treated like T_Index.
2978 assert(Converted.size() == 2 &&
2979 "__type_pack_element should be given an index and a parameter pack");
2981 // If the Index is out of bounds, the program is ill-formed.
2982 TemplateArgument IndexArg = Converted[0], Ts = Converted[1];
2983 llvm::APSInt Index = IndexArg.getAsIntegral();
2984 assert(Index >= 0 && "the index used with __type_pack_element should be of "
2985 "type std::size_t, and hence be non-negative");
2986 if (Index >= Ts.pack_size()) {
2987 SemaRef.Diag(TemplateArgs[0].getLocation(),
2988 diag::err_type_pack_element_out_of_bounds);
2992 // We simply return the type at index `Index`.
2993 auto Nth = std::next(Ts.pack_begin(), Index.getExtValue());
2994 return Nth->getAsType();
2996 llvm_unreachable("unexpected BuiltinTemplateDecl!");
2999 /// Determine whether this alias template is "enable_if_t".
3000 static bool isEnableIfAliasTemplate(TypeAliasTemplateDecl *AliasTemplate) {
3001 return AliasTemplate->getName().equals("enable_if_t");
3004 /// Collect all of the separable terms in the given condition, which
3005 /// might be a conjunction.
3007 /// FIXME: The right answer is to convert the logical expression into
3008 /// disjunctive normal form, so we can find the first failed term
3009 /// within each possible clause.
3010 static void collectConjunctionTerms(Expr *Clause,
3011 SmallVectorImpl<Expr *> &Terms) {
3012 if (auto BinOp = dyn_cast<BinaryOperator>(Clause->IgnoreParenImpCasts())) {
3013 if (BinOp->getOpcode() == BO_LAnd) {
3014 collectConjunctionTerms(BinOp->getLHS(), Terms);
3015 collectConjunctionTerms(BinOp->getRHS(), Terms);
3021 Terms.push_back(Clause);
3024 // The ranges-v3 library uses an odd pattern of a top-level "||" with
3025 // a left-hand side that is value-dependent but never true. Identify
3026 // the idiom and ignore that term.
3027 static Expr *lookThroughRangesV3Condition(Preprocessor &PP, Expr *Cond) {
3029 auto *BinOp = dyn_cast<BinaryOperator>(Cond->IgnoreParenImpCasts());
3030 if (!BinOp) return Cond;
3032 if (BinOp->getOpcode() != BO_LOr) return Cond;
3034 // With an inner '==' that has a literal on the right-hand side.
3035 Expr *LHS = BinOp->getLHS();
3036 auto *InnerBinOp = dyn_cast<BinaryOperator>(LHS->IgnoreParenImpCasts());
3037 if (!InnerBinOp) return Cond;
3039 if (InnerBinOp->getOpcode() != BO_EQ ||
3040 !isa<IntegerLiteral>(InnerBinOp->getRHS()))
3043 // If the inner binary operation came from a macro expansion named
3044 // CONCEPT_REQUIRES or CONCEPT_REQUIRES_, return the right-hand side
3045 // of the '||', which is the real, user-provided condition.
3046 SourceLocation Loc = InnerBinOp->getExprLoc();
3047 if (!Loc.isMacroID()) return Cond;
3049 StringRef MacroName = PP.getImmediateMacroName(Loc);
3050 if (MacroName == "CONCEPT_REQUIRES" || MacroName == "CONCEPT_REQUIRES_")
3051 return BinOp->getRHS();
3058 // A PrinterHelper that prints more helpful diagnostics for some sub-expressions
3059 // within failing boolean expression, such as substituting template parameters
3060 // for actual types.
3061 class FailedBooleanConditionPrinterHelper : public PrinterHelper {
3063 explicit FailedBooleanConditionPrinterHelper(const PrintingPolicy &P)
3066 bool handledStmt(Stmt *E, raw_ostream &OS) override {
3067 const auto *DR = dyn_cast<DeclRefExpr>(E);
3068 if (DR && DR->getQualifier()) {
3069 // If this is a qualified name, expand the template arguments in nested
3071 DR->getQualifier()->print(OS, Policy, true);
3072 // Then print the decl itself.
3073 const ValueDecl *VD = DR->getDecl();
3074 OS << VD->getName();
3075 if (const auto *IV = dyn_cast<VarTemplateSpecializationDecl>(VD)) {
3076 // This is a template variable, print the expanded template arguments.
3077 printTemplateArgumentList(OS, IV->getTemplateArgs().asArray(), Policy);
3085 const PrintingPolicy Policy;
3088 } // end anonymous namespace
3090 std::pair<Expr *, std::string>
3091 Sema::findFailedBooleanCondition(Expr *Cond) {
3092 Cond = lookThroughRangesV3Condition(PP, Cond);
3094 // Separate out all of the terms in a conjunction.
3095 SmallVector<Expr *, 4> Terms;
3096 collectConjunctionTerms(Cond, Terms);
3098 // Determine which term failed.
3099 Expr *FailedCond = nullptr;
3100 for (Expr *Term : Terms) {
3101 Expr *TermAsWritten = Term->IgnoreParenImpCasts();
3103 // Literals are uninteresting.
3104 if (isa<CXXBoolLiteralExpr>(TermAsWritten) ||
3105 isa<IntegerLiteral>(TermAsWritten))
3108 // The initialization of the parameter from the argument is
3109 // a constant-evaluated context.
3110 EnterExpressionEvaluationContext ConstantEvaluated(
3111 *this, Sema::ExpressionEvaluationContext::ConstantEvaluated);
3114 if (Term->EvaluateAsBooleanCondition(Succeeded, Context) &&
3116 FailedCond = TermAsWritten;
3121 FailedCond = Cond->IgnoreParenImpCasts();
3123 std::string Description;
3125 llvm::raw_string_ostream Out(Description);
3126 PrintingPolicy Policy = getPrintingPolicy();
3127 Policy.PrintCanonicalTypes = true;
3128 FailedBooleanConditionPrinterHelper Helper(Policy);
3129 FailedCond->printPretty(Out, &Helper, Policy, 0, "\n", nullptr);
3131 return { FailedCond, Description };
3134 QualType Sema::CheckTemplateIdType(TemplateName Name,
3135 SourceLocation TemplateLoc,
3136 TemplateArgumentListInfo &TemplateArgs) {
3137 DependentTemplateName *DTN
3138 = Name.getUnderlying().getAsDependentTemplateName();
3139 if (DTN && DTN->isIdentifier())
3140 // When building a template-id where the template-name is dependent,
3141 // assume the template is a type template. Either our assumption is
3142 // correct, or the code is ill-formed and will be diagnosed when the
3143 // dependent name is substituted.
3144 return Context.getDependentTemplateSpecializationType(ETK_None,
3145 DTN->getQualifier(),
3146 DTN->getIdentifier(),
3149 TemplateDecl *Template = Name.getAsTemplateDecl();
3150 if (!Template || isa<FunctionTemplateDecl>(Template) ||
3151 isa<VarTemplateDecl>(Template)) {
3152 // We might have a substituted template template parameter pack. If so,
3153 // build a template specialization type for it.
3154 if (Name.getAsSubstTemplateTemplateParmPack())
3155 return Context.getTemplateSpecializationType(Name, TemplateArgs);
3157 Diag(TemplateLoc, diag::err_template_id_not_a_type)
3159 NoteAllFoundTemplates(Name);
3163 // Check that the template argument list is well-formed for this
3165 SmallVector<TemplateArgument, 4> Converted;
3166 if (CheckTemplateArgumentList(Template, TemplateLoc, TemplateArgs,
3172 bool InstantiationDependent = false;
3173 if (TypeAliasTemplateDecl *AliasTemplate =
3174 dyn_cast<TypeAliasTemplateDecl>(Template)) {
3175 // Find the canonical type for this type alias template specialization.
3176 TypeAliasDecl *Pattern = AliasTemplate->getTemplatedDecl();
3177 if (Pattern->isInvalidDecl())
3180 TemplateArgumentList StackTemplateArgs(TemplateArgumentList::OnStack,
3183 // Only substitute for the innermost template argument list.
3184 MultiLevelTemplateArgumentList TemplateArgLists;
3185 TemplateArgLists.addOuterTemplateArguments(&StackTemplateArgs);
3186 unsigned Depth = AliasTemplate->getTemplateParameters()->getDepth();
3187 for (unsigned I = 0; I < Depth; ++I)
3188 TemplateArgLists.addOuterTemplateArguments(None);
3190 LocalInstantiationScope Scope(*this);
3191 InstantiatingTemplate Inst(*this, TemplateLoc, Template);
3192 if (Inst.isInvalid())
3195 CanonType = SubstType(Pattern->getUnderlyingType(),
3196 TemplateArgLists, AliasTemplate->getLocation(),
3197 AliasTemplate->getDeclName());
3198 if (CanonType.isNull()) {
3199 // If this was enable_if and we failed to find the nested type
3200 // within enable_if in a SFINAE context, dig out the specific
3201 // enable_if condition that failed and present that instead.
3202 if (isEnableIfAliasTemplate(AliasTemplate)) {
3203 if (auto DeductionInfo = isSFINAEContext()) {
3204 if (*DeductionInfo &&
3205 (*DeductionInfo)->hasSFINAEDiagnostic() &&
3206 (*DeductionInfo)->peekSFINAEDiagnostic().second.getDiagID() ==
3207 diag::err_typename_nested_not_found_enable_if &&
3208 TemplateArgs[0].getArgument().getKind()
3209 == TemplateArgument::Expression) {
3211 std::string FailedDescription;
3212 std::tie(FailedCond, FailedDescription) =
3213 findFailedBooleanCondition(TemplateArgs[0].getSourceExpression());
3215 // Remove the old SFINAE diagnostic.
3216 PartialDiagnosticAt OldDiag =
3217 {SourceLocation(), PartialDiagnostic::NullDiagnostic()};
3218 (*DeductionInfo)->takeSFINAEDiagnostic(OldDiag);
3220 // Add a new SFINAE diagnostic specifying which condition
3222 (*DeductionInfo)->addSFINAEDiagnostic(
3224 PDiag(diag::err_typename_nested_not_found_requirement)
3225 << FailedDescription
3226 << FailedCond->getSourceRange());
3233 } else if (Name.isDependent() ||
3234 TemplateSpecializationType::anyDependentTemplateArguments(
3235 TemplateArgs, InstantiationDependent)) {
3236 // This class template specialization is a dependent
3237 // type. Therefore, its canonical type is another class template
3238 // specialization type that contains all of the converted
3239 // arguments in canonical form. This ensures that, e.g., A<T> and
3240 // A<T, T> have identical types when A is declared as:
3242 // template<typename T, typename U = T> struct A;
3243 CanonType = Context.getCanonicalTemplateSpecializationType(Name, Converted);
3245 // This might work out to be a current instantiation, in which
3246 // case the canonical type needs to be the InjectedClassNameType.
3248 // TODO: in theory this could be a simple hashtable lookup; most
3249 // changes to CurContext don't change the set of current
3251 if (isa<ClassTemplateDecl>(Template)) {
3252 for (DeclContext *Ctx = CurContext; Ctx; Ctx = Ctx->getLookupParent()) {
3253 // If we get out to a namespace, we're done.
3254 if (Ctx->isFileContext()) break;
3256 // If this isn't a record, keep looking.
3257 CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(Ctx);
3258 if (!Record) continue;
3260 // Look for one of the two cases with InjectedClassNameTypes
3261 // and check whether it's the same template.
3262 if (!isa<ClassTemplatePartialSpecializationDecl>(Record) &&
3263 !Record->getDescribedClassTemplate())
3266 // Fetch the injected class name type and check whether its
3267 // injected type is equal to the type we just built.
3268 QualType ICNT = Context.getTypeDeclType(Record);
3269 QualType Injected = cast<InjectedClassNameType>(ICNT)
3270 ->getInjectedSpecializationType();
3272 if (CanonType != Injected->getCanonicalTypeInternal())
3275 // If so, the canonical type of this TST is the injected
3276 // class name type of the record we just found.
3277 assert(ICNT.isCanonical());
3282 } else if (ClassTemplateDecl *ClassTemplate
3283 = dyn_cast<ClassTemplateDecl>(Template)) {
3284 // Find the class template specialization declaration that
3285 // corresponds to these arguments.
3286 void *InsertPos = nullptr;
3287 ClassTemplateSpecializationDecl *Decl
3288 = ClassTemplate->findSpecialization(Converted, InsertPos);
3290 // This is the first time we have referenced this class template
3291 // specialization. Create the canonical declaration and add it to
3292 // the set of specializations.
3293 Decl = ClassTemplateSpecializationDecl::Create(
3294 Context, ClassTemplate->getTemplatedDecl()->getTagKind(),
3295 ClassTemplate->getDeclContext(),
3296 ClassTemplate->getTemplatedDecl()->getBeginLoc(),
3297 ClassTemplate->getLocation(), ClassTemplate, Converted, nullptr);
3298 ClassTemplate->AddSpecialization(Decl, InsertPos);
3299 if (ClassTemplate->isOutOfLine())
3300 Decl->setLexicalDeclContext(ClassTemplate->getLexicalDeclContext());
3303 if (Decl->getSpecializationKind() == TSK_Undeclared) {
3304 MultiLevelTemplateArgumentList TemplateArgLists;
3305 TemplateArgLists.addOuterTemplateArguments(Converted);
3306 InstantiateAttrsForDecl(TemplateArgLists, ClassTemplate->getTemplatedDecl(),
3310 // Diagnose uses of this specialization.
3311 (void)DiagnoseUseOfDecl(Decl, TemplateLoc);
3313 CanonType = Context.getTypeDeclType(Decl);
3314 assert(isa<RecordType>(CanonType) &&
3315 "type of non-dependent specialization is not a RecordType");
3316 } else if (auto *BTD = dyn_cast<BuiltinTemplateDecl>(Template)) {
3317 CanonType = checkBuiltinTemplateIdType(*this, BTD, Converted, TemplateLoc,
3321 // Build the fully-sugared type for this class template
3322 // specialization, which refers back to the class template
3323 // specialization we created or found.
3324 return Context.getTemplateSpecializationType(Name, TemplateArgs, CanonType);
3328 Sema::ActOnTemplateIdType(CXXScopeSpec &SS, SourceLocation TemplateKWLoc,
3329 TemplateTy TemplateD, IdentifierInfo *TemplateII,
3330 SourceLocation TemplateIILoc,
3331 SourceLocation LAngleLoc,
3332 ASTTemplateArgsPtr TemplateArgsIn,
3333 SourceLocation RAngleLoc,
3334 bool IsCtorOrDtorName, bool IsClassName) {
3338 if (!IsCtorOrDtorName && !IsClassName && SS.isSet()) {
3339 DeclContext *LookupCtx = computeDeclContext(SS, /*EnteringContext*/false);
3341 // C++ [temp.res]p3:
3342 // A qualified-id that refers to a type and in which the
3343 // nested-name-specifier depends on a template-parameter (14.6.2)
3344 // shall be prefixed by the keyword typename to indicate that the
3345 // qualified-id denotes a type, forming an
3346 // elaborated-type-specifier (7.1.5.3).
3347 if (!LookupCtx && isDependentScopeSpecifier(SS)) {
3348 Diag(SS.getBeginLoc(), diag::err_typename_missing_template)
3349 << SS.getScopeRep() << TemplateII->getName();
3350 // Recover as if 'typename' were specified.
3351 // FIXME: This is not quite correct recovery as we don't transform SS
3352 // into the corresponding dependent form (and we don't diagnose missing
3353 // 'template' keywords within SS as a result).
3354 return ActOnTypenameType(nullptr, SourceLocation(), SS, TemplateKWLoc,
3355 TemplateD, TemplateII, TemplateIILoc, LAngleLoc,
3356 TemplateArgsIn, RAngleLoc);
3359 // Per C++ [class.qual]p2, if the template-id was an injected-class-name,
3360 // it's not actually allowed to be used as a type in most cases. Because
3361 // we annotate it before we know whether it's valid, we have to check for
3363 auto *LookupRD = dyn_cast_or_null<CXXRecordDecl>(LookupCtx);
3364 if (LookupRD && LookupRD->getIdentifier() == TemplateII) {
3366 TemplateKWLoc.isInvalid()
3367 ? diag::err_out_of_line_qualified_id_type_names_constructor
3368 : diag::ext_out_of_line_qualified_id_type_names_constructor)
3369 << TemplateII << 0 /*injected-class-name used as template name*/
3370 << 1 /*if any keyword was present, it was 'template'*/;
3374 TemplateName Template = TemplateD.get();
3376 // Translate the parser's template argument list in our AST format.
3377 TemplateArgumentListInfo TemplateArgs(LAngleLoc, RAngleLoc);
3378 translateTemplateArguments(TemplateArgsIn, TemplateArgs);
3380 if (DependentTemplateName *DTN = Template.getAsDependentTemplateName()) {
3382 = Context.getDependentTemplateSpecializationType(ETK_None,
3383 DTN->getQualifier(),
3384 DTN->getIdentifier(),
3386 // Build type-source information.
3388 DependentTemplateSpecializationTypeLoc SpecTL
3389 = TLB.push<DependentTemplateSpecializationTypeLoc>(T);
3390 SpecTL.setElaboratedKeywordLoc(SourceLocation());
3391 SpecTL.setQualifierLoc(SS.getWithLocInContext(Context));
3392 SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
3393 SpecTL.setTemplateNameLoc(TemplateIILoc);
3394 SpecTL.setLAngleLoc(LAngleLoc);
3395 SpecTL.setRAngleLoc(RAngleLoc);
3396 for (unsigned I = 0, N = SpecTL.getNumArgs(); I != N; ++I)
3397 SpecTL.setArgLocInfo(I, TemplateArgs[I].getLocInfo());
3398 return CreateParsedType(T, TLB.getTypeSourceInfo(Context, T));
3401 QualType Result = CheckTemplateIdType(Template, TemplateIILoc, TemplateArgs);
3402 if (Result.isNull())
3405 // Build type-source information.
3407 TemplateSpecializationTypeLoc SpecTL
3408 = TLB.push<TemplateSpecializationTypeLoc>(Result);
3409 SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
3410 SpecTL.setTemplateNameLoc(TemplateIILoc);
3411 SpecTL.setLAngleLoc(LAngleLoc);
3412 SpecTL.setRAngleLoc(RAngleLoc);
3413 for (unsigned i = 0, e = SpecTL.getNumArgs(); i != e; ++i)
3414 SpecTL.setArgLocInfo(i, TemplateArgs[i].getLocInfo());
3416 // NOTE: avoid constructing an ElaboratedTypeLoc if this is a
3417 // constructor or destructor name (in such a case, the scope specifier
3418 // will be attached to the enclosing Decl or Expr node).
3419 if (SS.isNotEmpty() && !IsCtorOrDtorName) {
3420 // Create an elaborated-type-specifier containing the nested-name-specifier.
3421 Result = Context.getElaboratedType(ETK_None, SS.getScopeRep(), Result);
3422 ElaboratedTypeLoc ElabTL = TLB.push<ElaboratedTypeLoc>(Result);
3423 ElabTL.setElaboratedKeywordLoc(SourceLocation());
3424 ElabTL.setQualifierLoc(SS.getWithLocInContext(Context));
3427 return CreateParsedType(Result, TLB.getTypeSourceInfo(Context, Result));
3430 TypeResult Sema::ActOnTagTemplateIdType(TagUseKind TUK,
3431 TypeSpecifierType TagSpec,
3432 SourceLocation TagLoc,
3434 SourceLocation TemplateKWLoc,
3435 TemplateTy TemplateD,
3436 SourceLocation TemplateLoc,
3437 SourceLocation LAngleLoc,
3438 ASTTemplateArgsPtr TemplateArgsIn,
3439 SourceLocation RAngleLoc) {
3440 TemplateName Template = TemplateD.get();
3442 // Translate the parser's template argument list in our AST format.
3443 TemplateArgumentListInfo TemplateArgs(LAngleLoc, RAngleLoc);
3444 translateTemplateArguments(TemplateArgsIn, TemplateArgs);
3446 // Determine the tag kind
3447 TagTypeKind TagKind = TypeWithKeyword::getTagTypeKindForTypeSpec(TagSpec);
3448 ElaboratedTypeKeyword Keyword
3449 = TypeWithKeyword::getKeywordForTagTypeKind(TagKind);
3451 if (DependentTemplateName *DTN = Template.getAsDependentTemplateName()) {
3452 QualType T = Context.getDependentTemplateSpecializationType(Keyword,
3453 DTN->getQualifier(),
3454 DTN->getIdentifier(),
3457 // Build type-source information.
3459 DependentTemplateSpecializationTypeLoc SpecTL
3460 = TLB.push<DependentTemplateSpecializationTypeLoc>(T);
3461 SpecTL.setElaboratedKeywordLoc(TagLoc);
3462 SpecTL.setQualifierLoc(SS.getWithLocInContext(Context));
3463 SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
3464 SpecTL.setTemplateNameLoc(TemplateLoc);
3465 SpecTL.setLAngleLoc(LAngleLoc);
3466 SpecTL.setRAngleLoc(RAngleLoc);
3467 for (unsigned I = 0, N = SpecTL.getNumArgs(); I != N; ++I)
3468 SpecTL.setArgLocInfo(I, TemplateArgs[I].getLocInfo());
3469 return CreateParsedType(T, TLB.getTypeSourceInfo(Context, T));
3472 if (TypeAliasTemplateDecl *TAT =
3473 dyn_cast_or_null<TypeAliasTemplateDecl>(Template.getAsTemplateDecl())) {
3474 // C++0x [dcl.type.elab]p2:
3475 // If the identifier resolves to a typedef-name or the simple-template-id
3476 // resolves to an alias template specialization, the
3477 // elaborated-type-specifier is ill-formed.
3478 Diag(TemplateLoc, diag::err_tag_reference_non_tag)
3479 << TAT << NTK_TypeAliasTemplate << TagKind;
3480 Diag(TAT->getLocation(), diag::note_declared_at);
3483 QualType Result = CheckTemplateIdType(Template, TemplateLoc, TemplateArgs);
3484 if (Result.isNull())
3485 return TypeResult(true);
3487 // Check the tag kind
3488 if (const RecordType *RT = Result->getAs<RecordType>()) {
3489 RecordDecl *D = RT->getDecl();
3491 IdentifierInfo *Id = D->getIdentifier();
3492 assert(Id && "templated class must have an identifier");
3494 if (!isAcceptableTagRedeclaration(D, TagKind, TUK == TUK_Definition,
3496 Diag(TagLoc, diag::err_use_with_wrong_tag)
3498 << FixItHint::CreateReplacement(SourceRange(TagLoc), D->getKindName());
3499 Diag(D->getLocation(), diag::note_previous_use);
3503 // Provide source-location information for the template specialization.
3505 TemplateSpecializationTypeLoc SpecTL
3506 = TLB.push<TemplateSpecializationTypeLoc>(Result);
3507 SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
3508 SpecTL.setTemplateNameLoc(TemplateLoc);
3509 SpecTL.setLAngleLoc(LAngleLoc);
3510 SpecTL.setRAngleLoc(RAngleLoc);
3511 for (unsigned i = 0, e = SpecTL.getNumArgs(); i != e; ++i)
3512 SpecTL.setArgLocInfo(i, TemplateArgs[i].getLocInfo());
3514 // Construct an elaborated type containing the nested-name-specifier (if any)
3516 Result = Context.getElaboratedType(Keyword, SS.getScopeRep(), Result);
3517 ElaboratedTypeLoc ElabTL = TLB.push<ElaboratedTypeLoc>(Result);
3518 ElabTL.setElaboratedKeywordLoc(TagLoc);
3519 ElabTL.setQualifierLoc(SS.getWithLocInContext(Context));
3520 return CreateParsedType(Result, TLB.getTypeSourceInfo(Context, Result));
3523 static bool CheckTemplateSpecializationScope(Sema &S, NamedDecl *Specialized,
3524 NamedDecl *PrevDecl,
3526 bool IsPartialSpecialization);
3528 static TemplateSpecializationKind getTemplateSpecializationKind(Decl *D);
3530 static bool isTemplateArgumentTemplateParameter(
3531 const TemplateArgument &Arg, unsigned Depth, unsigned Index) {
3532 switch (Arg.getKind()) {
3533 case TemplateArgument::Null:
3534 case TemplateArgument::NullPtr:
3535 case TemplateArgument::Integral:
3536 case TemplateArgument::Declaration:
3537 case TemplateArgument::Pack:
3538 case TemplateArgument::TemplateExpansion:
3541 case TemplateArgument::Type: {
3542 QualType Type = Arg.getAsType();
3543 const TemplateTypeParmType *TPT =
3544 Arg.getAsType()->getAs<TemplateTypeParmType>();
3545 return TPT && !Type.hasQualifiers() &&
3546 TPT->getDepth() == Depth && TPT->getIndex() == Index;
3549 case TemplateArgument::Expression: {
3550 DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Arg.getAsExpr());
3551 if (!DRE || !DRE->getDecl())
3553 const NonTypeTemplateParmDecl *NTTP =
3554 dyn_cast<NonTypeTemplateParmDecl>(DRE->getDecl());
3555 return NTTP && NTTP->getDepth() == Depth && NTTP->getIndex() == Index;
3558 case TemplateArgument::Template:
3559 const TemplateTemplateParmDecl *TTP =
3560 dyn_cast_or_null<TemplateTemplateParmDecl>(
3561 Arg.getAsTemplateOrTemplatePattern().getAsTemplateDecl());
3562 return TTP && TTP->getDepth() == Depth && TTP->getIndex() == Index;
3564 llvm_unreachable("unexpected kind of template argument");
3567 static bool isSameAsPrimaryTemplate(TemplateParameterList *Params,
3568 ArrayRef<TemplateArgument> Args) {
3569 if (Params->size() != Args.size())
3572 unsigned Depth = Params->getDepth();
3574 for (unsigned I = 0, N = Args.size(); I != N; ++I) {
3575 TemplateArgument Arg = Args[I];
3577 // If the parameter is a pack expansion, the argument must be a pack
3578 // whose only element is a pack expansion.
3579 if (Params->getParam(I)->isParameterPack()) {
3580 if (Arg.getKind() != TemplateArgument::Pack || Arg.pack_size() != 1 ||
3581 !Arg.pack_begin()->isPackExpansion())
3583 Arg = Arg.pack_begin()->getPackExpansionPattern();
3586 if (!isTemplateArgumentTemplateParameter(Arg, Depth, I))
3593 /// Convert the parser's template argument list representation into our form.
3594 static TemplateArgumentListInfo
3595 makeTemplateArgumentListInfo(Sema &S, TemplateIdAnnotation &TemplateId) {
3596 TemplateArgumentListInfo TemplateArgs(TemplateId.LAngleLoc,
3597 TemplateId.RAngleLoc);
3598 ASTTemplateArgsPtr TemplateArgsPtr(TemplateId.getTemplateArgs(),
3599 TemplateId.NumArgs);
3600 S.translateTemplateArguments(TemplateArgsPtr, TemplateArgs);
3601 return TemplateArgs;
3604 template<typename PartialSpecDecl>
3605 static void checkMoreSpecializedThanPrimary(Sema &S, PartialSpecDecl *Partial) {
3606 if (Partial->getDeclContext()->isDependentContext())
3609 // FIXME: Get the TDK from deduction in order to provide better diagnostics
3610 // for non-substitution-failure issues?
3611 TemplateDeductionInfo Info(Partial->getLocation());
3612 if (S.isMoreSpecializedThanPrimary(Partial, Info))
3615 auto *Template = Partial->getSpecializedTemplate();
3616 S.Diag(Partial->getLocation(),
3617 diag::ext_partial_spec_not_more_specialized_than_primary)
3618 << isa<VarTemplateDecl>(Template);
3620 if (Info.hasSFINAEDiagnostic()) {
3621 PartialDiagnosticAt Diag = {SourceLocation(),
3622 PartialDiagnostic::NullDiagnostic()};
3623 Info.takeSFINAEDiagnostic(Diag);
3624 SmallString<128> SFINAEArgString;
3625 Diag.second.EmitToString(S.getDiagnostics(), SFINAEArgString);
3627 diag::note_partial_spec_not_more_specialized_than_primary)
3631 S.Diag(Template->getLocation(), diag::note_template_decl_here);
3635 noteNonDeducibleParameters(Sema &S, TemplateParameterList *TemplateParams,
3636 const llvm::SmallBitVector &DeducibleParams) {
3637 for (unsigned I = 0, N = DeducibleParams.size(); I != N; ++I) {
3638 if (!DeducibleParams[I]) {
3639 NamedDecl *Param = TemplateParams->getParam(I);
3640 if (Param->getDeclName())
3641 S.Diag(Param->getLocation(), diag::note_non_deducible_parameter)
3642 << Param->getDeclName();
3644 S.Diag(Param->getLocation(), diag::note_non_deducible_parameter)
3651 template<typename PartialSpecDecl>
3652 static void checkTemplatePartialSpecialization(Sema &S,
3653 PartialSpecDecl *Partial) {
3654 // C++1z [temp.class.spec]p8: (DR1495)
3655 // - The specialization shall be more specialized than the primary
3656 // template (14.5.5.2).
3657 checkMoreSpecializedThanPrimary(S, Partial);
3659 // C++ [temp.class.spec]p8: (DR1315)
3660 // - Each template-parameter shall appear at least once in the
3661 // template-id outside a non-deduced context.
3662 // C++1z [temp.class.spec.match]p3 (P0127R2)
3663 // If the template arguments of a partial specialization cannot be
3664 // deduced because of the structure of its template-parameter-list
3665 // and the template-id, the program is ill-formed.
3666 auto *TemplateParams = Partial->getTemplateParameters();
3667 llvm::SmallBitVector DeducibleParams(TemplateParams->size());
3668 S.MarkUsedTemplateParameters(Partial->getTemplateArgs(), true,
3669 TemplateParams->getDepth(), DeducibleParams);
3671 if (!DeducibleParams.all()) {
3672 unsigned NumNonDeducible = DeducibleParams.size() - DeducibleParams.count();
3673 S.Diag(Partial->getLocation(), diag::ext_partial_specs_not_deducible)
3674 << isa<VarTemplatePartialSpecializationDecl>(Partial)
3675 << (NumNonDeducible > 1)
3676 << SourceRange(Partial->getLocation(),
3677 Partial->getTemplateArgsAsWritten()->RAngleLoc);
3678 noteNonDeducibleParameters(S, TemplateParams, DeducibleParams);
3682 void Sema::CheckTemplatePartialSpecialization(
3683 ClassTemplatePartialSpecializationDecl *Partial) {
3684 checkTemplatePartialSpecialization(*this, Partial);
3687 void Sema::CheckTemplatePartialSpecialization(
3688 VarTemplatePartialSpecializationDecl *Partial) {
3689 checkTemplatePartialSpecialization(*this, Partial);
3692 void Sema::CheckDeductionGuideTemplate(FunctionTemplateDecl *TD) {
3693 // C++1z [temp.param]p11:
3694 // A template parameter of a deduction guide template that does not have a
3695 // default-argument shall be deducible from the parameter-type-list of the
3696 // deduction guide template.
3697 auto *TemplateParams = TD->getTemplateParameters();
3698 llvm::SmallBitVector DeducibleParams(TemplateParams->size());
3699 MarkDeducedTemplateParameters(TD, DeducibleParams);
3700 for (unsigned I = 0; I != TemplateParams->size(); ++I) {
3701 // A parameter pack is deducible (to an empty pack).
3702 auto *Param = TemplateParams->getParam(I);
3703 if (Param->isParameterPack() || hasVisibleDefaultArgument(Param))
3704 DeducibleParams[I] = true;
3707 if (!DeducibleParams.all()) {
3708 unsigned NumNonDeducible = DeducibleParams.size() - DeducibleParams.count();
3709 Diag(TD->getLocation(), diag::err_deduction_guide_template_not_deducible)
3710 << (NumNonDeducible > 1);
3711 noteNonDeducibleParameters(*this, TemplateParams, DeducibleParams);
3715 DeclResult Sema::ActOnVarTemplateSpecialization(
3716 Scope *S, Declarator &D, TypeSourceInfo *DI, SourceLocation TemplateKWLoc,
3717 TemplateParameterList *TemplateParams, StorageClass SC,
3718 bool IsPartialSpecialization) {
3719 // D must be variable template id.
3720 assert(D.getName().getKind() == UnqualifiedIdKind::IK_TemplateId &&
3721 "Variable template specialization is declared with a template it.");
3723 TemplateIdAnnotation *TemplateId = D.getName().TemplateId;
3724 TemplateArgumentListInfo TemplateArgs =
3725 makeTemplateArgumentListInfo(*this, *TemplateId);
3726 SourceLocation TemplateNameLoc = D.getIdentifierLoc();
3727 SourceLocation LAngleLoc = TemplateId->LAngleLoc;
3728 SourceLocation RAngleLoc = TemplateId->RAngleLoc;
3730 TemplateName Name = TemplateId->Template.get();
3732 // The template-id must name a variable template.
3733 VarTemplateDecl *VarTemplate =
3734 dyn_cast_or_null<VarTemplateDecl>(Name.getAsTemplateDecl());
3736 NamedDecl *FnTemplate;
3737 if (auto *OTS = Name.getAsOverloadedTemplate())
3738 FnTemplate = *OTS->begin();
3740 FnTemplate = dyn_cast_or_null<FunctionTemplateDecl>(Name.getAsTemplateDecl());
3742 return Diag(D.getIdentifierLoc(), diag::err_var_spec_no_template_but_method)
3743 << FnTemplate->getDeclName();
3744 return Diag(D.getIdentifierLoc(), diag::err_var_spec_no_template)
3745 << IsPartialSpecialization;
3748 // Check for unexpanded parameter packs in any of the template arguments.
3749 for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I)
3750 if (DiagnoseUnexpandedParameterPack(TemplateArgs[I],
3751 UPPC_PartialSpecialization))
3754 // Check that the template argument list is well-formed for this
3756 SmallVector<TemplateArgument, 4> Converted;
3757 if (CheckTemplateArgumentList(VarTemplate, TemplateNameLoc, TemplateArgs,
3761 // Find the variable template (partial) specialization declaration that
3762 // corresponds to these arguments.
3763 if (IsPartialSpecialization) {
3764 if (CheckTemplatePartialSpecializationArgs(TemplateNameLoc, VarTemplate,
3765 TemplateArgs.size(), Converted))
3768 // FIXME: Move these checks to CheckTemplatePartialSpecializationArgs so we
3769 // also do them during instantiation.
3770 bool InstantiationDependent;
3771 if (!Name.isDependent() &&
3772 !TemplateSpecializationType::anyDependentTemplateArguments(
3773 TemplateArgs.arguments(),
3774 InstantiationDependent)) {
3775 Diag(TemplateNameLoc, diag::err_partial_spec_fully_specialized)
3776 << VarTemplate->getDeclName();
3777 IsPartialSpecialization = false;
3780 if (isSameAsPrimaryTemplate(VarTemplate->getTemplateParameters(),
3782 // C++ [temp.class.spec]p9b3:
3784 // -- The argument list of the specialization shall not be identical
3785 // to the implicit argument list of the primary template.
3786 Diag(TemplateNameLoc, diag::err_partial_spec_args_match_primary_template)
3787 << /*variable template*/ 1
3788 << /*is definition*/(SC != SC_Extern && !CurContext->isRecord())
3789 << FixItHint::CreateRemoval(SourceRange(LAngleLoc, RAngleLoc));
3790 // FIXME: Recover from this by treating the declaration as a redeclaration
3791 // of the primary template.
3796 void *InsertPos = nullptr;
3797 VarTemplateSpecializationDecl *PrevDecl = nullptr;
3799 if (IsPartialSpecialization)
3800 // FIXME: Template parameter list matters too
3801 PrevDecl = VarTemplate->findPartialSpecialization(Converted, InsertPos);
3803 PrevDecl = VarTemplate->findSpecialization(Converted, InsertPos);
3805 VarTemplateSpecializationDecl *Specialization = nullptr;
3807 // Check whether we can declare a variable template specialization in
3808 // the current scope.
3809 if (CheckTemplateSpecializationScope(*this, VarTemplate, PrevDecl,
3811 IsPartialSpecialization))
3814 if (PrevDecl && PrevDecl->getSpecializationKind() == TSK_Undeclared) {
3815 // Since the only prior variable template specialization with these
3816 // arguments was referenced but not declared, reuse that
3817 // declaration node as our own, updating its source location and
3818 // the list of outer template parameters to reflect our new declaration.
3819 Specialization = PrevDecl;
3820 Specialization->setLocation(TemplateNameLoc);
3822 } else if (IsPartialSpecialization) {
3823 // Create a new class template partial specialization declaration node.
3824 VarTemplatePartialSpecializationDecl *PrevPartial =
3825 cast_or_null<VarTemplatePartialSpecializationDecl>(PrevDecl);
3826 VarTemplatePartialSpecializationDecl *Partial =
3827 VarTemplatePartialSpecializationDecl::Create(
3828 Context, VarTemplate->getDeclContext(), TemplateKWLoc,
3829 TemplateNameLoc, TemplateParams, VarTemplate, DI->getType(), DI, SC,
3830 Converted, TemplateArgs);
3833 VarTemplate->AddPartialSpecialization(Partial, InsertPos);
3834 Specialization = Partial;
3836 // If we are providing an explicit specialization of a member variable
3837 // template specialization, make a note of that.
3838 if (PrevPartial && PrevPartial->getInstantiatedFromMember())
3839 PrevPartial->setMemberSpecialization();
3841 CheckTemplatePartialSpecialization(Partial);
3843 // Create a new class template specialization declaration node for
3844 // this explicit specialization or friend declaration.
3845 Specialization = VarTemplateSpecializationDecl::Create(
3846 Context, VarTemplate->getDeclContext(), TemplateKWLoc, TemplateNameLoc,
3847 VarTemplate, DI->getType(), DI, SC, Converted);
3848 Specialization->setTemplateArgsInfo(TemplateArgs);
3851 VarTemplate->AddSpecialization(Specialization, InsertPos);
3854 // C++ [temp.expl.spec]p6:
3855 // If a template, a member template or the member of a class template is
3856 // explicitly specialized then that specialization shall be declared
3857 // before the first use of that specialization that would cause an implicit
3858 // instantiation to take place, in every translation unit in which such a
3859 // use occurs; no diagnostic is required.
3860 if (PrevDecl && PrevDecl->getPointOfInstantiation().isValid()) {
3862 for (Decl *Prev = PrevDecl; Prev; Prev = Prev->getPreviousDecl()) {
3863 // Is there any previous explicit specialization declaration?
3864 if (getTemplateSpecializationKind(Prev) == TSK_ExplicitSpecialization) {
3871 SourceRange Range(TemplateNameLoc, RAngleLoc);
3872 Diag(TemplateNameLoc, diag::err_specialization_after_instantiation)
3875 Diag(PrevDecl->getPointOfInstantiation(),
3876 diag::note_instantiation_required_here)
3877 << (PrevDecl->getTemplateSpecializationKind() !=
3878 TSK_ImplicitInstantiation);
3883 Specialization->setTemplateKeywordLoc(TemplateKWLoc);
3884 Specialization->setLexicalDeclContext(CurContext);
3886 // Add the specialization into its lexical context, so that it can
3887 // be seen when iterating through the list of declarations in that
3888 // context. However, specializations are not found by name lookup.
3889 CurContext->addDecl(Specialization);
3891 // Note that this is an explicit specialization.
3892 Specialization->setSpecializationKind(TSK_ExplicitSpecialization);
3895 // Check that this isn't a redefinition of this specialization,
3896 // merging with previous declarations.
3897 LookupResult PrevSpec(*this, GetNameForDeclarator(D), LookupOrdinaryName,
3898 forRedeclarationInCurContext());
3899 PrevSpec.addDecl(PrevDecl);
3900 D.setRedeclaration(CheckVariableDeclaration(Specialization, PrevSpec));
3901 } else if (Specialization->isStaticDataMember() &&
3902 Specialization->isOutOfLine()) {
3903 Specialization->setAccess(VarTemplate->getAccess());
3906 // Link instantiations of static data members back to the template from
3907 // which they were instantiated.
3908 if (Specialization->isStaticDataMember())
3909 Specialization->setInstantiationOfStaticDataMember(
3910 VarTemplate->getTemplatedDecl(),
3911 Specialization->getSpecializationKind());
3913 return Specialization;
3917 /// A partial specialization whose template arguments have matched
3918 /// a given template-id.
3919 struct PartialSpecMatchResult {
3920 VarTemplatePartialSpecializationDecl *Partial;
3921 TemplateArgumentList *Args;
3923 } // end anonymous namespace
3926 Sema::CheckVarTemplateId(VarTemplateDecl *Template, SourceLocation TemplateLoc,
3927 SourceLocation TemplateNameLoc,
3928 const TemplateArgumentListInfo &TemplateArgs) {
3929 assert(Template && "A variable template id without template?");
3931 // Check that the template argument list is well-formed for this template.
3932 SmallVector<TemplateArgument, 4> Converted;
3933 if (CheckTemplateArgumentList(
3934 Template, TemplateNameLoc,
3935 const_cast<TemplateArgumentListInfo &>(TemplateArgs), false,
3939 // Find the variable template specialization declaration that
3940 // corresponds to these arguments.
3941 void *InsertPos = nullptr;
3942 if (VarTemplateSpecializationDecl *Spec = Template->findSpecialization(
3943 Converted, InsertPos)) {
3944 checkSpecializationVisibility(TemplateNameLoc, Spec);
3945 // If we already have a variable template specialization, return it.
3949 // This is the first time we have referenced this variable template
3950 // specialization. Create the canonical declaration and add it to
3951 // the set of specializations, based on the closest partial specialization
3952 // that it represents. That is,
3953 VarDecl *InstantiationPattern = Template->getTemplatedDecl();
3954 TemplateArgumentList TemplateArgList(TemplateArgumentList::OnStack,
3956 TemplateArgumentList *InstantiationArgs = &TemplateArgList;
3957 bool AmbiguousPartialSpec = false;
3958 typedef PartialSpecMatchResult MatchResult;
3959 SmallVector<MatchResult, 4> Matched;
3960 SourceLocation PointOfInstantiation = TemplateNameLoc;
3961 TemplateSpecCandidateSet FailedCandidates(PointOfInstantiation,
3962 /*ForTakingAddress=*/false);
3964 // 1. Attempt to find the closest partial specialization that this
3965 // specializes, if any.
3966 // If any of the template arguments is dependent, then this is probably
3967 // a placeholder for an incomplete declarative context; which must be
3968 // complete by instantiation time. Thus, do not search through the partial
3969 // specializations yet.
3970 // TODO: Unify with InstantiateClassTemplateSpecialization()?
3971 // Perhaps better after unification of DeduceTemplateArguments() and
3972 // getMoreSpecializedPartialSpecialization().
3973 bool InstantiationDependent = false;
3974 if (!TemplateSpecializationType::anyDependentTemplateArguments(
3975 TemplateArgs, InstantiationDependent)) {
3977 SmallVector<VarTemplatePartialSpecializationDecl *, 4> PartialSpecs;
3978 Template->getPartialSpecializations(PartialSpecs);
3980 for (unsigned I = 0, N = PartialSpecs.size(); I != N; ++I) {
3981 VarTemplatePartialSpecializationDecl *Partial = PartialSpecs[I];
3982 TemplateDeductionInfo Info(FailedCandidates.getLocation());
3984 if (TemplateDeductionResult Result =
3985 DeduceTemplateArguments(Partial, TemplateArgList, Info)) {
3986 // Store the failed-deduction information for use in diagnostics, later.
3987 // TODO: Actually use the failed-deduction info?
3988 FailedCandidates.addCandidate().set(
3989 DeclAccessPair::make(Template, AS_public), Partial,
3990 MakeDeductionFailureInfo(Context, Result, Info));
3993 Matched.push_back(PartialSpecMatchResult());
3994 Matched.back().Partial = Partial;
3995 Matched.back().Args = Info.take();
3999 if (Matched.size() >= 1) {
4000 SmallVector<MatchResult, 4>::iterator Best = Matched.begin();
4001 if (Matched.size() == 1) {
4002 // -- If exactly one matching specialization is found, the
4003 // instantiation is generated from that specialization.
4004 // We don't need to do anything for this.
4006 // -- If more than one matching specialization is found, the
4007 // partial order rules (14.5.4.2) are used to determine
4008 // whether one of the specializations is more specialized
4009 // than the others. If none of the specializations is more
4010 // specialized than all of the other matching
4011 // specializations, then the use of the variable template is
4012 // ambiguous and the program is ill-formed.
4013 for (SmallVector<MatchResult, 4>::iterator P = Best + 1,
4014 PEnd = Matched.end();
4016 if (getMoreSpecializedPartialSpecialization(P->Partial, Best->Partial,
4017 PointOfInstantiation) ==
4022 // Determine if the best partial specialization is more specialized than
4024 for (SmallVector<MatchResult, 4>::iterator P = Matched.begin(),
4025 PEnd = Matched.end();
4027 if (P != Best && getMoreSpecializedPartialSpecialization(
4028 P->Partial, Best->Partial,
4029 PointOfInstantiation) != Best->Partial) {
4030 AmbiguousPartialSpec = true;
4036 // Instantiate using the best variable template partial specialization.
4037 InstantiationPattern = Best->Partial;
4038 InstantiationArgs = Best->Args;
4040 // -- If no match is found, the instantiation is generated
4041 // from the primary template.
4042 // InstantiationPattern = Template->getTemplatedDecl();
4046 // 2. Create the canonical declaration.
4047 // Note that we do not instantiate a definition until we see an odr-use
4048 // in DoMarkVarDeclReferenced().
4049 // FIXME: LateAttrs et al.?
4050 VarTemplateSpecializationDecl *Decl = BuildVarTemplateInstantiation(
4051 Template, InstantiationPattern, *InstantiationArgs, TemplateArgs,
4052 Converted, TemplateNameLoc, InsertPos /*, LateAttrs, StartingScope*/);
4056 if (AmbiguousPartialSpec) {
4057 // Partial ordering did not produce a clear winner. Complain.
4058 Decl->setInvalidDecl();
4059 Diag(PointOfInstantiation, diag::err_partial_spec_ordering_ambiguous)
4062 // Print the matching partial specializations.
4063 for (MatchResult P : Matched)
4064 Diag(P.Partial->getLocation(), diag::note_partial_spec_match)
4065 << getTemplateArgumentBindingsText(P.Partial->getTemplateParameters(),
4070 if (VarTemplatePartialSpecializationDecl *D =
4071 dyn_cast<VarTemplatePartialSpecializationDecl>(InstantiationPattern))
4072 Decl->setInstantiationOf(D, InstantiationArgs);
4074 checkSpecializationVisibility(TemplateNameLoc, Decl);
4076 assert(Decl && "No variable template specialization?");
4081 Sema::CheckVarTemplateId(const CXXScopeSpec &SS,
4082 const DeclarationNameInfo &NameInfo,
4083 VarTemplateDecl *Template, SourceLocation TemplateLoc,
4084 const TemplateArgumentListInfo *TemplateArgs) {
4086 DeclResult Decl = CheckVarTemplateId(Template, TemplateLoc, NameInfo.getLoc(),
4088 if (Decl.isInvalid())
4091 VarDecl *Var = cast<VarDecl>(Decl.get());
4092 if (!Var->getTemplateSpecializationKind())
4093 Var->setTemplateSpecializationKind(TSK_ImplicitInstantiation,
4096 // Build an ordinary singleton decl ref.
4097 return BuildDeclarationNameExpr(SS, NameInfo, Var,
4098 /*FoundD=*/nullptr, TemplateArgs);
4101 void Sema::diagnoseMissingTemplateArguments(TemplateName Name,
4102 SourceLocation Loc) {
4103 Diag(Loc, diag::err_template_missing_args)
4104 << (int)getTemplateNameKindForDiagnostics(Name) << Name;
4105 if (TemplateDecl *TD = Name.getAsTemplateDecl()) {
4106 Diag(TD->getLocation(), diag::note_template_decl_here)
4107 << TD->getTemplateParameters()->getSourceRange();
4111 ExprResult Sema::BuildTemplateIdExpr(const CXXScopeSpec &SS,
4112 SourceLocation TemplateKWLoc,
4115 const TemplateArgumentListInfo *TemplateArgs) {
4116 // FIXME: Can we do any checking at this point? I guess we could check the
4117 // template arguments that we have against the template name, if the template
4118 // name refers to a single template. That's not a terribly common case,
4120 // foo<int> could identify a single function unambiguously
4121 // This approach does NOT work, since f<int>(1);
4122 // gets resolved prior to resorting to overload resolution
4123 // i.e., template<class T> void f(double);
4124 // vs template<class T, class U> void f(U);
4126 // These should be filtered out by our callers.
4127 assert(!R.empty() && "empty lookup results when building templateid");
4128 assert(!R.isAmbiguous() && "ambiguous lookup when building templateid");
4130 // Non-function templates require a template argument list.
4131 if (auto *TD = R.getAsSingle<TemplateDecl>()) {
4132 if (!TemplateArgs && !isa<FunctionTemplateDecl>(TD)) {
4133 diagnoseMissingTemplateArguments(TemplateName(TD), R.getNameLoc());
4138 auto AnyDependentArguments = [&]() -> bool {
4139 bool InstantiationDependent;
4140 return TemplateArgs &&
4141 TemplateSpecializationType::anyDependentTemplateArguments(
4142 *TemplateArgs, InstantiationDependent);
4145 // In C++1y, check variable template ids.
4146 if (R.getAsSingle<VarTemplateDecl>() && !AnyDependentArguments()) {
4147 return CheckVarTemplateId(SS, R.getLookupNameInfo(),
4148 R.getAsSingle<VarTemplateDecl>(),
4149 TemplateKWLoc, TemplateArgs);
4152 // We don't want lookup warnings at this point.
4153 R.suppressDiagnostics();
4155 UnresolvedLookupExpr *ULE
4156 = UnresolvedLookupExpr::Create(Context, R.getNamingClass(),
4157 SS.getWithLocInContext(Context),
4159 R.getLookupNameInfo(),
4160 RequiresADL, TemplateArgs,
4161 R.begin(), R.end());
4166 // We actually only call this from template instantiation.
4168 Sema::BuildQualifiedTemplateIdExpr(CXXScopeSpec &SS,
4169 SourceLocation TemplateKWLoc,
4170 const DeclarationNameInfo &NameInfo,
4171 const TemplateArgumentListInfo *TemplateArgs) {
4173 assert(TemplateArgs || TemplateKWLoc.isValid());
4175 if (!(DC = computeDeclContext(SS, false)) ||
4176 DC->isDependentContext() ||
4177 RequireCompleteDeclContext(SS, DC))
4178 return BuildDependentDeclRefExpr(SS, TemplateKWLoc, NameInfo, TemplateArgs);
4180 bool MemberOfUnknownSpecialization;
4181 LookupResult R(*this, NameInfo, LookupOrdinaryName);
4182 if (LookupTemplateName(R, (Scope *)nullptr, SS, QualType(),
4183 /*Entering*/false, MemberOfUnknownSpecialization,
4187 if (R.isAmbiguous())
4191 Diag(NameInfo.getLoc(), diag::err_no_member)
4192 << NameInfo.getName() << DC << SS.getRange();
4196 if (ClassTemplateDecl *Temp = R.getAsSingle<ClassTemplateDecl>()) {
4197 Diag(NameInfo.getLoc(), diag::err_template_kw_refers_to_class_template)
4199 << NameInfo.getName().getAsString() << SS.getRange();
4200 Diag(Temp->getLocation(), diag::note_referenced_class_template);
4204 return BuildTemplateIdExpr(SS, TemplateKWLoc, R, /*ADL*/ false, TemplateArgs);
4207 /// Form a dependent template name.
4209 /// This action forms a dependent template name given the template
4210 /// name and its (presumably dependent) scope specifier. For
4211 /// example, given "MetaFun::template apply", the scope specifier \p
4212 /// SS will be "MetaFun::", \p TemplateKWLoc contains the location
4213 /// of the "template" keyword, and "apply" is the \p Name.
4214 TemplateNameKind Sema::ActOnDependentTemplateName(Scope *S,
4216 SourceLocation TemplateKWLoc,
4217 const UnqualifiedId &Name,
4218 ParsedType ObjectType,
4219 bool EnteringContext,
4221 bool AllowInjectedClassName) {
4222 if (TemplateKWLoc.isValid() && S && !S->getTemplateParamParent())
4224 getLangOpts().CPlusPlus11 ?
4225 diag::warn_cxx98_compat_template_outside_of_template :
4226 diag::ext_template_outside_of_template)
4227 << FixItHint::CreateRemoval(TemplateKWLoc);
4229 DeclContext *LookupCtx = nullptr;
4231 LookupCtx = computeDeclContext(SS, EnteringContext);
4232 if (!LookupCtx && ObjectType)
4233 LookupCtx = computeDeclContext(ObjectType.get());
4235 // C++0x [temp.names]p5:
4236 // If a name prefixed by the keyword template is not the name of
4237 // a template, the program is ill-formed. [Note: the keyword
4238 // template may not be applied to non-template members of class
4239 // templates. -end note ] [ Note: as is the case with the
4240 // typename prefix, the template prefix is allowed in cases
4241 // where it is not strictly necessary; i.e., when the
4242 // nested-name-specifier or the expression on the left of the ->
4243 // or . is not dependent on a template-parameter, or the use
4244 // does not appear in the scope of a template. -end note]
4246 // Note: C++03 was more strict here, because it banned the use of
4247 // the "template" keyword prior to a template-name that was not a
4248 // dependent name. C++ DR468 relaxed this requirement (the
4249 // "template" keyword is now permitted). We follow the C++0x
4250 // rules, even in C++03 mode with a warning, retroactively applying the DR.
4251 bool MemberOfUnknownSpecialization;
4252 TemplateNameKind TNK = isTemplateName(S, SS, TemplateKWLoc.isValid(), Name,
4253 ObjectType, EnteringContext, Result,
4254 MemberOfUnknownSpecialization);
4255 if (TNK == TNK_Non_template && MemberOfUnknownSpecialization) {
4256 // This is a dependent template. Handle it below.
4257 } else if (TNK == TNK_Non_template) {
4258 // Do the lookup again to determine if this is a "nothing found" case or
4259 // a "not a template" case. FIXME: Refactor isTemplateName so we don't
4261 DeclarationNameInfo DNI = GetNameFromUnqualifiedId(Name);
4262 LookupResult R(*this, DNI.getName(), Name.getBeginLoc(),
4263 LookupOrdinaryName);
4265 if (!LookupTemplateName(R, S, SS, ObjectType.get(), EnteringContext,
4266 MOUS, TemplateKWLoc))
4267 Diag(Name.getBeginLoc(), diag::err_no_member)
4268 << DNI.getName() << LookupCtx << SS.getRange();
4269 return TNK_Non_template;
4271 // We found something; return it.
4272 auto *LookupRD = dyn_cast<CXXRecordDecl>(LookupCtx);
4273 if (!AllowInjectedClassName && SS.isSet() && LookupRD &&
4274 Name.getKind() == UnqualifiedIdKind::IK_Identifier &&
4275 Name.Identifier && LookupRD->getIdentifier() == Name.Identifier) {
4276 // C++14 [class.qual]p2:
4277 // In a lookup in which function names are not ignored and the
4278 // nested-name-specifier nominates a class C, if the name specified
4279 // [...] is the injected-class-name of C, [...] the name is instead
4280 // considered to name the constructor
4282 // We don't get here if naming the constructor would be valid, so we
4283 // just reject immediately and recover by treating the
4284 // injected-class-name as naming the template.
4285 Diag(Name.getBeginLoc(),
4286 diag::ext_out_of_line_qualified_id_type_names_constructor)
4288 << 0 /*injected-class-name used as template name*/
4289 << 1 /*'template' keyword was used*/;
4295 NestedNameSpecifier *Qualifier = SS.getScopeRep();
4297 switch (Name.getKind()) {
4298 case UnqualifiedIdKind::IK_Identifier:
4299 Result = TemplateTy::make(Context.getDependentTemplateName(Qualifier,
4301 return TNK_Dependent_template_name;
4303 case UnqualifiedIdKind::IK_OperatorFunctionId:
4304 Result = TemplateTy::make(Context.getDependentTemplateName(Qualifier,
4305 Name.OperatorFunctionId.Operator));
4306 return TNK_Function_template;
4308 case UnqualifiedIdKind::IK_LiteralOperatorId:
4309 llvm_unreachable("literal operator id cannot have a dependent scope");
4315 Diag(Name.getBeginLoc(), diag::err_template_kw_refers_to_non_template)
4316 << GetNameFromUnqualifiedId(Name).getName() << Name.getSourceRange()
4318 return TNK_Non_template;
4321 bool Sema::CheckTemplateTypeArgument(TemplateTypeParmDecl *Param,
4322 TemplateArgumentLoc &AL,
4323 SmallVectorImpl<TemplateArgument> &Converted) {
4324 const TemplateArgument &Arg = AL.getArgument();
4326 TypeSourceInfo *TSI = nullptr;
4328 // Check template type parameter.
4329 switch(Arg.getKind()) {
4330 case TemplateArgument::Type:
4331 // C++ [temp.arg.type]p1:
4332 // A template-argument for a template-parameter which is a
4333 // type shall be a type-id.
4334 ArgType = Arg.getAsType();
4335 TSI = AL.getTypeSourceInfo();
4337 case TemplateArgument::Template:
4338 case TemplateArgument::TemplateExpansion: {
4339 // We have a template type parameter but the template argument
4340 // is a template without any arguments.
4341 SourceRange SR = AL.getSourceRange();
4342 TemplateName Name = Arg.getAsTemplateOrTemplatePattern();
4343 diagnoseMissingTemplateArguments(Name, SR.getEnd());
4346 case TemplateArgument::Expression: {
4347 // We have a template type parameter but the template argument is an
4348 // expression; see if maybe it is missing the "typename" keyword.
4350 DeclarationNameInfo NameInfo;
4352 if (DeclRefExpr *ArgExpr = dyn_cast<DeclRefExpr>(Arg.getAsExpr())) {
4353 SS.Adopt(ArgExpr->getQualifierLoc());
4354 NameInfo = ArgExpr->getNameInfo();
4355 } else if (DependentScopeDeclRefExpr *ArgExpr =
4356 dyn_cast<DependentScopeDeclRefExpr>(Arg.getAsExpr())) {
4357 SS.Adopt(ArgExpr->getQualifierLoc());
4358 NameInfo = ArgExpr->getNameInfo();
4359 } else if (CXXDependentScopeMemberExpr *ArgExpr =
4360 dyn_cast<CXXDependentScopeMemberExpr>(Arg.getAsExpr())) {
4361 if (ArgExpr->isImplicitAccess()) {
4362 SS.Adopt(ArgExpr->getQualifierLoc());
4363 NameInfo = ArgExpr->getMemberNameInfo();
4367 if (auto *II = NameInfo.getName().getAsIdentifierInfo()) {
4368 LookupResult Result(*this, NameInfo, LookupOrdinaryName);
4369 LookupParsedName(Result, CurScope, &SS);
4371 if (Result.getAsSingle<TypeDecl>() ||
4372 Result.getResultKind() ==
4373 LookupResult::NotFoundInCurrentInstantiation) {
4374 // Suggest that the user add 'typename' before the NNS.
4375 SourceLocation Loc = AL.getSourceRange().getBegin();
4376 Diag(Loc, getLangOpts().MSVCCompat
4377 ? diag::ext_ms_template_type_arg_missing_typename
4378 : diag::err_template_arg_must_be_type_suggest)
4379 << FixItHint::CreateInsertion(Loc, "typename ");
4380 Diag(Param->getLocation(), diag::note_template_param_here);
4382 // Recover by synthesizing a type using the location information that we
4385 Context.getDependentNameType(ETK_Typename, SS.getScopeRep(), II);
4387 DependentNameTypeLoc TL = TLB.push<DependentNameTypeLoc>(ArgType);
4388 TL.setElaboratedKeywordLoc(SourceLocation(/*synthesized*/));
4389 TL.setQualifierLoc(SS.getWithLocInContext(Context));
4390 TL.setNameLoc(NameInfo.getLoc());
4391 TSI = TLB.getTypeSourceInfo(Context, ArgType);
4393 // Overwrite our input TemplateArgumentLoc so that we can recover
4395 AL = TemplateArgumentLoc(TemplateArgument(ArgType),
4396 TemplateArgumentLocInfo(TSI));
4405 // We have a template type parameter but the template argument
4407 SourceRange SR = AL.getSourceRange();
4408 Diag(SR.getBegin(), diag::err_template_arg_must_be_type) << SR;
4409 Diag(Param->getLocation(), diag::note_template_param_here);
4415 if (CheckTemplateArgument(Param, TSI))
4418 // Add the converted template type argument.
4419 ArgType = Context.getCanonicalType(ArgType);
4422 // If an explicitly-specified template argument type is a lifetime type
4423 // with no lifetime qualifier, the __strong lifetime qualifier is inferred.
4424 if (getLangOpts().ObjCAutoRefCount &&
4425 ArgType->isObjCLifetimeType() &&
4426 !ArgType.getObjCLifetime()) {
4428 Qs.setObjCLifetime(Qualifiers::OCL_Strong);
4429 ArgType = Context.getQualifiedType(ArgType, Qs);
4432 Converted.push_back(TemplateArgument(ArgType));
4436 /// Substitute template arguments into the default template argument for
4437 /// the given template type parameter.
4439 /// \param SemaRef the semantic analysis object for which we are performing
4440 /// the substitution.
4442 /// \param Template the template that we are synthesizing template arguments
4445 /// \param TemplateLoc the location of the template name that started the
4446 /// template-id we are checking.
4448 /// \param RAngleLoc the location of the right angle bracket ('>') that
4449 /// terminates the template-id.
4451 /// \param Param the template template parameter whose default we are
4452 /// substituting into.
4454 /// \param Converted the list of template arguments provided for template
4455 /// parameters that precede \p Param in the template parameter list.
4456 /// \returns the substituted template argument, or NULL if an error occurred.
4457 static TypeSourceInfo *
4458 SubstDefaultTemplateArgument(Sema &SemaRef,
4459 TemplateDecl *Template,
4460 SourceLocation TemplateLoc,
4461 SourceLocation RAngleLoc,
4462 TemplateTypeParmDecl *Param,
4463 SmallVectorImpl<TemplateArgument> &Converted) {
4464 TypeSourceInfo *ArgType = Param->getDefaultArgumentInfo();
4466 // If the argument type is dependent, instantiate it now based
4467 // on the previously-computed template arguments.
4468 if (ArgType->getType()->isInstantiationDependentType()) {
4469 Sema::InstantiatingTemplate Inst(SemaRef, TemplateLoc,
4470 Param, Template, Converted,
4471 SourceRange(TemplateLoc, RAngleLoc));
4472 if (Inst.isInvalid())
4475 TemplateArgumentList TemplateArgs(TemplateArgumentList::OnStack, Converted);
4477 // Only substitute for the innermost template argument list.
4478 MultiLevelTemplateArgumentList TemplateArgLists;
4479 TemplateArgLists.addOuterTemplateArguments(&TemplateArgs);
4480 for (unsigned i = 0, e = Param->getDepth(); i != e; ++i)
4481 TemplateArgLists.addOuterTemplateArguments(None);
4483 Sema::ContextRAII SavedContext(SemaRef, Template->getDeclContext());
4485 SemaRef.SubstType(ArgType, TemplateArgLists,
4486 Param->getDefaultArgumentLoc(), Param->getDeclName());
4492 /// Substitute template arguments into the default template argument for
4493 /// the given non-type template parameter.
4495 /// \param SemaRef the semantic analysis object for which we are performing
4496 /// the substitution.
4498 /// \param Template the template that we are synthesizing template arguments
4501 /// \param TemplateLoc the location of the template name that started the
4502 /// template-id we are checking.
4504 /// \param RAngleLoc the location of the right angle bracket ('>') that
4505 /// terminates the template-id.
4507 /// \param Param the non-type template parameter whose default we are
4508 /// substituting into.
4510 /// \param Converted the list of template arguments provided for template
4511 /// parameters that precede \p Param in the template parameter list.
4513 /// \returns the substituted template argument, or NULL if an error occurred.
4515 SubstDefaultTemplateArgument(Sema &SemaRef,
4516 TemplateDecl *Template,
4517 SourceLocation TemplateLoc,
4518 SourceLocation RAngleLoc,
4519 NonTypeTemplateParmDecl *Param,
4520 SmallVectorImpl<TemplateArgument> &Converted) {
4521 Sema::InstantiatingTemplate Inst(SemaRef, TemplateLoc,
4522 Param, Template, Converted,
4523 SourceRange(TemplateLoc, RAngleLoc));
4524 if (Inst.isInvalid())
4527 TemplateArgumentList TemplateArgs(TemplateArgumentList::OnStack, Converted);
4529 // Only substitute for the innermost template argument list.
4530 MultiLevelTemplateArgumentList TemplateArgLists;
4531 TemplateArgLists.addOuterTemplateArguments(&TemplateArgs);
4532 for (unsigned i = 0, e = Param->getDepth(); i != e; ++i)
4533 TemplateArgLists.addOuterTemplateArguments(None);
4535 EnterExpressionEvaluationContext ConstantEvaluated(
4536 SemaRef, Sema::ExpressionEvaluationContext::ConstantEvaluated);
4537 return SemaRef.SubstExpr(Param->getDefaultArgument(), TemplateArgLists);
4540 /// Substitute template arguments into the default template argument for
4541 /// the given template template parameter.
4543 /// \param SemaRef the semantic analysis object for which we are performing
4544 /// the substitution.
4546 /// \param Template the template that we are synthesizing template arguments
4549 /// \param TemplateLoc the location of the template name that started the
4550 /// template-id we are checking.
4552 /// \param RAngleLoc the location of the right angle bracket ('>') that
4553 /// terminates the template-id.
4555 /// \param Param the template template parameter whose default we are
4556 /// substituting into.
4558 /// \param Converted the list of template arguments provided for template
4559 /// parameters that precede \p Param in the template parameter list.
4561 /// \param QualifierLoc Will be set to the nested-name-specifier (with
4562 /// source-location information) that precedes the template name.
4564 /// \returns the substituted template argument, or NULL if an error occurred.
4566 SubstDefaultTemplateArgument(Sema &SemaRef,
4567 TemplateDecl *Template,
4568 SourceLocation TemplateLoc,
4569 SourceLocation RAngleLoc,
4570 TemplateTemplateParmDecl *Param,
4571 SmallVectorImpl<TemplateArgument> &Converted,
4572 NestedNameSpecifierLoc &QualifierLoc) {
4573 Sema::InstantiatingTemplate Inst(
4574 SemaRef, TemplateLoc, TemplateParameter(Param), Template, Converted,
4575 SourceRange(TemplateLoc, RAngleLoc));
4576 if (Inst.isInvalid())
4577 return TemplateName();
4579 TemplateArgumentList TemplateArgs(TemplateArgumentList::OnStack, Converted);
4581 // Only substitute for the innermost template argument list.
4582 MultiLevelTemplateArgumentList TemplateArgLists;
4583 TemplateArgLists.addOuterTemplateArguments(&TemplateArgs);
4584 for (unsigned i = 0, e = Param->getDepth(); i != e; ++i)
4585 TemplateArgLists.addOuterTemplateArguments(None);
4587 Sema::ContextRAII SavedContext(SemaRef, Template->getDeclContext());
4588 // Substitute into the nested-name-specifier first,
4589 QualifierLoc = Param->getDefaultArgument().getTemplateQualifierLoc();
4592 SemaRef.SubstNestedNameSpecifierLoc(QualifierLoc, TemplateArgLists);
4594 return TemplateName();
4597 return SemaRef.SubstTemplateName(
4599 Param->getDefaultArgument().getArgument().getAsTemplate(),
4600 Param->getDefaultArgument().getTemplateNameLoc(),
4604 /// If the given template parameter has a default template
4605 /// argument, substitute into that default template argument and
4606 /// return the corresponding template argument.
4608 Sema::SubstDefaultTemplateArgumentIfAvailable(TemplateDecl *Template,
4609 SourceLocation TemplateLoc,
4610 SourceLocation RAngleLoc,
4612 SmallVectorImpl<TemplateArgument>
4614 bool &HasDefaultArg) {
4615 HasDefaultArg = false;
4617 if (TemplateTypeParmDecl *TypeParm = dyn_cast<TemplateTypeParmDecl>(Param)) {
4618 if (!hasVisibleDefaultArgument(TypeParm))
4619 return TemplateArgumentLoc();
4621 HasDefaultArg = true;
4622 TypeSourceInfo *DI = SubstDefaultTemplateArgument(*this, Template,
4628 return TemplateArgumentLoc(TemplateArgument(DI->getType()), DI);
4630 return TemplateArgumentLoc();
4633 if (NonTypeTemplateParmDecl *NonTypeParm
4634 = dyn_cast<NonTypeTemplateParmDecl>(Param)) {
4635 if (!hasVisibleDefaultArgument(NonTypeParm))
4636 return TemplateArgumentLoc();
4638 HasDefaultArg = true;
4639 ExprResult Arg = SubstDefaultTemplateArgument(*this, Template,
4644 if (Arg.isInvalid())
4645 return TemplateArgumentLoc();
4647 Expr *ArgE = Arg.getAs<Expr>();
4648 return TemplateArgumentLoc(TemplateArgument(ArgE), ArgE);
4651 TemplateTemplateParmDecl *TempTempParm
4652 = cast<TemplateTemplateParmDecl>(Param);
4653 if (!hasVisibleDefaultArgument(TempTempParm))
4654 return TemplateArgumentLoc();
4656 HasDefaultArg = true;
4657 NestedNameSpecifierLoc QualifierLoc;
4658 TemplateName TName = SubstDefaultTemplateArgument(*this, Template,
4665 return TemplateArgumentLoc();
4667 return TemplateArgumentLoc(TemplateArgument(TName),
4668 TempTempParm->getDefaultArgument().getTemplateQualifierLoc(),
4669 TempTempParm->getDefaultArgument().getTemplateNameLoc());
4672 /// Convert a template-argument that we parsed as a type into a template, if
4673 /// possible. C++ permits injected-class-names to perform dual service as
4674 /// template template arguments and as template type arguments.
4675 static TemplateArgumentLoc convertTypeTemplateArgumentToTemplate(TypeLoc TLoc) {
4676 // Extract and step over any surrounding nested-name-specifier.
4677 NestedNameSpecifierLoc QualLoc;
4678 if (auto ETLoc = TLoc.getAs<ElaboratedTypeLoc>()) {
4679 if (ETLoc.getTypePtr()->getKeyword() != ETK_None)
4680 return TemplateArgumentLoc();
4682 QualLoc = ETLoc.getQualifierLoc();
4683 TLoc = ETLoc.getNamedTypeLoc();
4686 // If this type was written as an injected-class-name, it can be used as a
4687 // template template argument.
4688 if (auto InjLoc = TLoc.getAs<InjectedClassNameTypeLoc>())
4689 return TemplateArgumentLoc(InjLoc.getTypePtr()->getTemplateName(),
4690 QualLoc, InjLoc.getNameLoc());
4692 // If this type was written as an injected-class-name, it may have been
4693 // converted to a RecordType during instantiation. If the RecordType is
4694 // *not* wrapped in a TemplateSpecializationType and denotes a class
4695 // template specialization, it must have come from an injected-class-name.
4696 if (auto RecLoc = TLoc.getAs<RecordTypeLoc>())
4698 dyn_cast<ClassTemplateSpecializationDecl>(RecLoc.getDecl()))
4699 return TemplateArgumentLoc(TemplateName(CTSD->getSpecializedTemplate()),
4700 QualLoc, RecLoc.getNameLoc());
4702 return TemplateArgumentLoc();
4705 /// Check that the given template argument corresponds to the given
4706 /// template parameter.
4708 /// \param Param The template parameter against which the argument will be
4711 /// \param Arg The template argument, which may be updated due to conversions.
4713 /// \param Template The template in which the template argument resides.
4715 /// \param TemplateLoc The location of the template name for the template
4716 /// whose argument list we're matching.
4718 /// \param RAngleLoc The location of the right angle bracket ('>') that closes
4719 /// the template argument list.
4721 /// \param ArgumentPackIndex The index into the argument pack where this
4722 /// argument will be placed. Only valid if the parameter is a parameter pack.
4724 /// \param Converted The checked, converted argument will be added to the
4725 /// end of this small vector.
4727 /// \param CTAK Describes how we arrived at this particular template argument:
4728 /// explicitly written, deduced, etc.
4730 /// \returns true on error, false otherwise.
4731 bool Sema::CheckTemplateArgument(NamedDecl *Param,
4732 TemplateArgumentLoc &Arg,
4733 NamedDecl *Template,
4734 SourceLocation TemplateLoc,
4735 SourceLocation RAngleLoc,
4736 unsigned ArgumentPackIndex,
4737 SmallVectorImpl<TemplateArgument> &Converted,
4738 CheckTemplateArgumentKind CTAK) {
4739 // Check template type parameters.
4740 if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(Param))
4741 return CheckTemplateTypeArgument(TTP, Arg, Converted);
4743 // Check non-type template parameters.
4744 if (NonTypeTemplateParmDecl *NTTP =dyn_cast<NonTypeTemplateParmDecl>(Param)) {
4745 // Do substitution on the type of the non-type template parameter
4746 // with the template arguments we've seen thus far. But if the
4747 // template has a dependent context then we cannot substitute yet.
4748 QualType NTTPType = NTTP->getType();
4749 if (NTTP->isParameterPack() && NTTP->isExpandedParameterPack())
4750 NTTPType = NTTP->getExpansionType(ArgumentPackIndex);
4752 // FIXME: Do we need to substitute into parameters here if they're
4753 // instantiation-dependent but not dependent?
4754 if (NTTPType->isDependentType() &&
4755 !isa<TemplateTemplateParmDecl>(Template) &&
4756 !Template->getDeclContext()->isDependentContext()) {
4757 // Do substitution on the type of the non-type template parameter.
4758 InstantiatingTemplate Inst(*this, TemplateLoc, Template,
4760 SourceRange(TemplateLoc, RAngleLoc));
4761 if (Inst.isInvalid())
4764 TemplateArgumentList TemplateArgs(TemplateArgumentList::OnStack,
4766 NTTPType = SubstType(NTTPType,
4767 MultiLevelTemplateArgumentList(TemplateArgs),
4768 NTTP->getLocation(),
4769 NTTP->getDeclName());
4770 // If that worked, check the non-type template parameter type
4772 if (!NTTPType.isNull())
4773 NTTPType = CheckNonTypeTemplateParameterType(NTTPType,
4774 NTTP->getLocation());
4775 if (NTTPType.isNull())
4779 switch (Arg.getArgument().getKind()) {
4780 case TemplateArgument::Null:
4781 llvm_unreachable("Should never see a NULL template argument here");
4783 case TemplateArgument::Expression: {
4784 TemplateArgument Result;
4785 unsigned CurSFINAEErrors = NumSFINAEErrors;
4787 CheckTemplateArgument(NTTP, NTTPType, Arg.getArgument().getAsExpr(),
4789 if (Res.isInvalid())
4791 // If the current template argument causes an error, give up now.
4792 if (CurSFINAEErrors < NumSFINAEErrors)
4795 // If the resulting expression is new, then use it in place of the
4796 // old expression in the template argument.
4797 if (Res.get() != Arg.getArgument().getAsExpr()) {
4798 TemplateArgument TA(Res.get());
4799 Arg = TemplateArgumentLoc(TA, Res.get());
4802 Converted.push_back(Result);
4806 case TemplateArgument::Declaration:
4807 case TemplateArgument::Integral:
4808 case TemplateArgument::NullPtr:
4809 // We've already checked this template argument, so just copy
4810 // it to the list of converted arguments.
4811 Converted.push_back(Arg.getArgument());
4814 case TemplateArgument::Template:
4815 case TemplateArgument::TemplateExpansion:
4816 // We were given a template template argument. It may not be ill-formed;
4818 if (DependentTemplateName *DTN
4819 = Arg.getArgument().getAsTemplateOrTemplatePattern()
4820 .getAsDependentTemplateName()) {
4821 // We have a template argument such as \c T::template X, which we
4822 // parsed as a template template argument. However, since we now
4823 // know that we need a non-type template argument, convert this
4824 // template name into an expression.
4826 DeclarationNameInfo NameInfo(DTN->getIdentifier(),
4827 Arg.getTemplateNameLoc());
4830 SS.Adopt(Arg.getTemplateQualifierLoc());
4831 // FIXME: the template-template arg was a DependentTemplateName,
4832 // so it was provided with a template keyword. However, its source
4833 // location is not stored in the template argument structure.
4834 SourceLocation TemplateKWLoc;
4835 ExprResult E = DependentScopeDeclRefExpr::Create(
4836 Context, SS.getWithLocInContext(Context), TemplateKWLoc, NameInfo,
4839 // If we parsed the template argument as a pack expansion, create a
4840 // pack expansion expression.
4841 if (Arg.getArgument().getKind() == TemplateArgument::TemplateExpansion){
4842 E = ActOnPackExpansion(E.get(), Arg.getTemplateEllipsisLoc());
4847 TemplateArgument Result;
4848 E = CheckTemplateArgument(NTTP, NTTPType, E.get(), Result);
4852 Converted.push_back(Result);
4856 // We have a template argument that actually does refer to a class
4857 // template, alias template, or template template parameter, and
4858 // therefore cannot be a non-type template argument.
4859 Diag(Arg.getLocation(), diag::err_template_arg_must_be_expr)
4860 << Arg.getSourceRange();
4862 Diag(Param->getLocation(), diag::note_template_param_here);
4865 case TemplateArgument::Type: {
4866 // We have a non-type template parameter but the template
4867 // argument is a type.
4869 // C++ [temp.arg]p2:
4870 // In a template-argument, an ambiguity between a type-id and
4871 // an expression is resolved to a type-id, regardless of the
4872 // form of the corresponding template-parameter.
4874 // We warn specifically about this case, since it can be rather
4875 // confusing for users.
4876 QualType T = Arg.getArgument().getAsType();
4877 SourceRange SR = Arg.getSourceRange();
4878 if (T->isFunctionType())
4879 Diag(SR.getBegin(), diag::err_template_arg_nontype_ambig) << SR << T;
4881 Diag(SR.getBegin(), diag::err_template_arg_must_be_expr) << SR;
4882 Diag(Param->getLocation(), diag::note_template_param_here);
4886 case TemplateArgument::Pack:
4887 llvm_unreachable("Caller must expand template argument packs");
4894 // Check template template parameters.
4895 TemplateTemplateParmDecl *TempParm = cast<TemplateTemplateParmDecl>(Param);
4897 TemplateParameterList *Params = TempParm->getTemplateParameters();
4898 if (TempParm->isExpandedParameterPack())
4899 Params = TempParm->getExpansionTemplateParameters(ArgumentPackIndex);
4901 // Substitute into the template parameter list of the template
4902 // template parameter, since previously-supplied template arguments
4903 // may appear within the template template parameter.
4905 // FIXME: Skip this if the parameters aren't instantiation-dependent.
4907 // Set up a template instantiation context.
4908 LocalInstantiationScope Scope(*this);
4909 InstantiatingTemplate Inst(*this, TemplateLoc, Template,
4910 TempParm, Converted,
4911 SourceRange(TemplateLoc, RAngleLoc));
4912 if (Inst.isInvalid())
4915 TemplateArgumentList TemplateArgs(TemplateArgumentList::OnStack, Converted);
4916 Params = SubstTemplateParams(Params, CurContext,
4917 MultiLevelTemplateArgumentList(TemplateArgs));
4922 // C++1z [temp.local]p1: (DR1004)
4923 // When [the injected-class-name] is used [...] as a template-argument for
4924 // a template template-parameter [...] it refers to the class template
4926 if (Arg.getArgument().getKind() == TemplateArgument::Type) {
4927 TemplateArgumentLoc ConvertedArg = convertTypeTemplateArgumentToTemplate(
4928 Arg.getTypeSourceInfo()->getTypeLoc());
4929 if (!ConvertedArg.getArgument().isNull())
4933 switch (Arg.getArgument().getKind()) {
4934 case TemplateArgument::Null:
4935 llvm_unreachable("Should never see a NULL template argument here");
4937 case TemplateArgument::Template:
4938 case TemplateArgument::TemplateExpansion:
4939 if (CheckTemplateTemplateArgument(Params, Arg))
4942 Converted.push_back(Arg.getArgument());
4945 case TemplateArgument::Expression:
4946 case TemplateArgument::Type:
4947 // We have a template template parameter but the template
4948 // argument does not refer to a template.
4949 Diag(Arg.getLocation(), diag::err_template_arg_must_be_template)
4950 << getLangOpts().CPlusPlus11;
4953 case TemplateArgument::Declaration:
4954 llvm_unreachable("Declaration argument with template template parameter");
4955 case TemplateArgument::Integral:
4956 llvm_unreachable("Integral argument with template template parameter");
4957 case TemplateArgument::NullPtr:
4958 llvm_unreachable("Null pointer argument with template template parameter");
4960 case TemplateArgument::Pack:
4961 llvm_unreachable("Caller must expand template argument packs");
4967 /// Check whether the template parameter is a pack expansion, and if so,
4968 /// determine the number of parameters produced by that expansion. For instance:
4971 /// template<typename ...Ts> struct A {
4972 /// template<Ts ...NTs, template<Ts> class ...TTs, typename ...Us> struct B;
4976 /// In \c A<int,int>::B, \c NTs and \c TTs have expanded pack size 2, and \c Us
4977 /// is not a pack expansion, so returns an empty Optional.
4978 static Optional<unsigned> getExpandedPackSize(NamedDecl *Param) {
4979 if (NonTypeTemplateParmDecl *NTTP
4980 = dyn_cast<NonTypeTemplateParmDecl>(Param)) {
4981 if (NTTP->isExpandedParameterPack())
4982 return NTTP->getNumExpansionTypes();
4985 if (TemplateTemplateParmDecl *TTP
4986 = dyn_cast<TemplateTemplateParmDecl>(Param)) {
4987 if (TTP->isExpandedParameterPack())
4988 return TTP->getNumExpansionTemplateParameters();
4994 /// Diagnose a missing template argument.
4995 template<typename TemplateParmDecl>
4996 static bool diagnoseMissingArgument(Sema &S, SourceLocation Loc,
4998 const TemplateParmDecl *D,
4999 TemplateArgumentListInfo &Args) {
5000 // Dig out the most recent declaration of the template parameter; there may be
5001 // declarations of the template that are more recent than TD.
5002 D = cast<TemplateParmDecl>(cast<TemplateDecl>(TD->getMostRecentDecl())
5003 ->getTemplateParameters()
5004 ->getParam(D->getIndex()));
5006 // If there's a default argument that's not visible, diagnose that we're
5007 // missing a module import.
5008 llvm::SmallVector<Module*, 8> Modules;
5009 if (D->hasDefaultArgument() && !S.hasVisibleDefaultArgument(D, &Modules)) {
5010 S.diagnoseMissingImport(Loc, cast<NamedDecl>(TD),
5011 D->getDefaultArgumentLoc(), Modules,
5012 Sema::MissingImportKind::DefaultArgument,
5017 // FIXME: If there's a more recent default argument that *is* visible,
5018 // diagnose that it was declared too late.
5020 TemplateParameterList *Params = TD->getTemplateParameters();
5022 S.Diag(Loc, diag::err_template_arg_list_different_arity)
5023 << /*not enough args*/0
5024 << (int)S.getTemplateNameKindForDiagnostics(TemplateName(TD))
5026 S.Diag(TD->getLocation(), diag::note_template_decl_here)
5027 << Params->getSourceRange();
5031 /// Check that the given template argument list is well-formed
5032 /// for specializing the given template.
5033 bool Sema::CheckTemplateArgumentList(
5034 TemplateDecl *Template, SourceLocation TemplateLoc,
5035 TemplateArgumentListInfo &TemplateArgs, bool PartialTemplateArgs,
5036 SmallVectorImpl<TemplateArgument> &Converted,
5037 bool UpdateArgsWithConversions) {
5038 // Make a copy of the template arguments for processing. Only make the
5039 // changes at the end when successful in matching the arguments to the
5041 TemplateArgumentListInfo NewArgs = TemplateArgs;
5043 // Make sure we get the template parameter list from the most
5044 // recentdeclaration, since that is the only one that has is guaranteed to
5045 // have all the default template argument information.
5046 TemplateParameterList *Params =
5047 cast<TemplateDecl>(Template->getMostRecentDecl())
5048 ->getTemplateParameters();
5050 SourceLocation RAngleLoc = NewArgs.getRAngleLoc();
5052 // C++ [temp.arg]p1:
5053 // [...] The type and form of each template-argument specified in
5054 // a template-id shall match the type and form specified for the
5055 // corresponding parameter declared by the template in its
5056 // template-parameter-list.
5057 bool isTemplateTemplateParameter = isa<TemplateTemplateParmDecl>(Template);
5058 SmallVector<TemplateArgument, 2> ArgumentPack;
5059 unsigned ArgIdx = 0, NumArgs = NewArgs.size();
5060 LocalInstantiationScope InstScope(*this, true);
5061 for (TemplateParameterList::iterator Param = Params->begin(),
5062 ParamEnd = Params->end();
5063 Param != ParamEnd; /* increment in loop */) {
5064 // If we have an expanded parameter pack, make sure we don't have too
5066 if (Optional<unsigned> Expansions = getExpandedPackSize(*Param)) {
5067 if (*Expansions == ArgumentPack.size()) {
5068 // We're done with this parameter pack. Pack up its arguments and add
5069 // them to the list.
5070 Converted.push_back(
5071 TemplateArgument::CreatePackCopy(Context, ArgumentPack));
5072 ArgumentPack.clear();
5074 // This argument is assigned to the next parameter.
5077 } else if (ArgIdx == NumArgs && !PartialTemplateArgs) {
5078 // Not enough arguments for this parameter pack.
5079 Diag(TemplateLoc, diag::err_template_arg_list_different_arity)
5080 << /*not enough args*/0
5081 << (int)getTemplateNameKindForDiagnostics(TemplateName(Template))
5083 Diag(Template->getLocation(), diag::note_template_decl_here)
5084 << Params->getSourceRange();
5089 if (ArgIdx < NumArgs) {
5090 // Check the template argument we were given.
5091 if (CheckTemplateArgument(*Param, NewArgs[ArgIdx], Template,
5092 TemplateLoc, RAngleLoc,
5093 ArgumentPack.size(), Converted))
5096 bool PackExpansionIntoNonPack =
5097 NewArgs[ArgIdx].getArgument().isPackExpansion() &&
5098 (!(*Param)->isTemplateParameterPack() || getExpandedPackSize(*Param));
5099 if (PackExpansionIntoNonPack && isa<TypeAliasTemplateDecl>(Template)) {
5100 // Core issue 1430: we have a pack expansion as an argument to an
5101 // alias template, and it's not part of a parameter pack. This
5102 // can't be canonicalized, so reject it now.
5103 Diag(NewArgs[ArgIdx].getLocation(),
5104 diag::err_alias_template_expansion_into_fixed_list)
5105 << NewArgs[ArgIdx].getSourceRange();
5106 Diag((*Param)->getLocation(), diag::note_template_param_here);
5110 // We're now done with this argument.
5113 if ((*Param)->isTemplateParameterPack()) {
5114 // The template parameter was a template parameter pack, so take the
5115 // deduced argument and place it on the argument pack. Note that we
5116 // stay on the same template parameter so that we can deduce more
5118 ArgumentPack.push_back(Converted.pop_back_val());
5120 // Move to the next template parameter.
5124 // If we just saw a pack expansion into a non-pack, then directly convert
5125 // the remaining arguments, because we don't know what parameters they'll
5127 if (PackExpansionIntoNonPack) {
5128 if (!ArgumentPack.empty()) {
5129 // If we were part way through filling in an expanded parameter pack,
5130 // fall back to just producing individual arguments.
5131 Converted.insert(Converted.end(),
5132 ArgumentPack.begin(), ArgumentPack.end());
5133 ArgumentPack.clear();
5136 while (ArgIdx < NumArgs) {
5137 Converted.push_back(NewArgs[ArgIdx].getArgument());
5147 // If we're checking a partial template argument list, we're done.
5148 if (PartialTemplateArgs) {
5149 if ((*Param)->isTemplateParameterPack() && !ArgumentPack.empty())
5150 Converted.push_back(
5151 TemplateArgument::CreatePackCopy(Context, ArgumentPack));
5156 // If we have a template parameter pack with no more corresponding
5157 // arguments, just break out now and we'll fill in the argument pack below.
5158 if ((*Param)->isTemplateParameterPack()) {
5159 assert(!getExpandedPackSize(*Param) &&
5160 "Should have dealt with this already");
5162 // A non-expanded parameter pack before the end of the parameter list
5163 // only occurs for an ill-formed template parameter list, unless we've
5164 // got a partial argument list for a function template, so just bail out.
5165 if (Param + 1 != ParamEnd)
5168 Converted.push_back(
5169 TemplateArgument::CreatePackCopy(Context, ArgumentPack));
5170 ArgumentPack.clear();
5176 // Check whether we have a default argument.
5177 TemplateArgumentLoc Arg;
5179 // Retrieve the default template argument from the template
5180 // parameter. For each kind of template parameter, we substitute the
5181 // template arguments provided thus far and any "outer" template arguments
5182 // (when the template parameter was part of a nested template) into
5183 // the default argument.
5184 if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(*Param)) {
5185 if (!hasVisibleDefaultArgument(TTP))
5186 return diagnoseMissingArgument(*this, TemplateLoc, Template, TTP,
5189 TypeSourceInfo *ArgType = SubstDefaultTemplateArgument(*this,
5198 Arg = TemplateArgumentLoc(TemplateArgument(ArgType->getType()),
5200 } else if (NonTypeTemplateParmDecl *NTTP
5201 = dyn_cast<NonTypeTemplateParmDecl>(*Param)) {
5202 if (!hasVisibleDefaultArgument(NTTP))
5203 return diagnoseMissingArgument(*this, TemplateLoc, Template, NTTP,
5206 ExprResult E = SubstDefaultTemplateArgument(*this, Template,
5214 Expr *Ex = E.getAs<Expr>();
5215 Arg = TemplateArgumentLoc(TemplateArgument(Ex), Ex);
5217 TemplateTemplateParmDecl *TempParm
5218 = cast<TemplateTemplateParmDecl>(*Param);
5220 if (!hasVisibleDefaultArgument(TempParm))
5221 return diagnoseMissingArgument(*this, TemplateLoc, Template, TempParm,
5224 NestedNameSpecifierLoc QualifierLoc;
5225 TemplateName Name = SubstDefaultTemplateArgument(*this, Template,
5234 Arg = TemplateArgumentLoc(TemplateArgument(Name), QualifierLoc,
5235 TempParm->getDefaultArgument().getTemplateNameLoc());
5238 // Introduce an instantiation record that describes where we are using
5239 // the default template argument. We're not actually instantiating a
5240 // template here, we just create this object to put a note into the
5242 InstantiatingTemplate Inst(*this, RAngleLoc, Template, *Param, Converted,
5243 SourceRange(TemplateLoc, RAngleLoc));
5244 if (Inst.isInvalid())
5247 // Check the default template argument.
5248 if (CheckTemplateArgument(*Param, Arg, Template, TemplateLoc,
5249 RAngleLoc, 0, Converted))
5252 // Core issue 150 (assumed resolution): if this is a template template
5253 // parameter, keep track of the default template arguments from the
5254 // template definition.
5255 if (isTemplateTemplateParameter)
5256 NewArgs.addArgument(Arg);
5258 // Move to the next template parameter and argument.
5263 // If we're performing a partial argument substitution, allow any trailing
5264 // pack expansions; they might be empty. This can happen even if
5265 // PartialTemplateArgs is false (the list of arguments is complete but
5266 // still dependent).
5267 if (ArgIdx < NumArgs && CurrentInstantiationScope &&
5268 CurrentInstantiationScope->getPartiallySubstitutedPack()) {
5269 while (ArgIdx < NumArgs && NewArgs[ArgIdx].getArgument().isPackExpansion())
5270 Converted.push_back(NewArgs[ArgIdx++].getArgument());
5273 // If we have any leftover arguments, then there were too many arguments.
5274 // Complain and fail.
5275 if (ArgIdx < NumArgs) {
5276 Diag(TemplateLoc, diag::err_template_arg_list_different_arity)
5277 << /*too many args*/1
5278 << (int)getTemplateNameKindForDiagnostics(TemplateName(Template))
5280 << SourceRange(NewArgs[ArgIdx].getLocation(), NewArgs.getRAngleLoc());
5281 Diag(Template->getLocation(), diag::note_template_decl_here)
5282 << Params->getSourceRange();
5286 // No problems found with the new argument list, propagate changes back
5288 if (UpdateArgsWithConversions)
5289 TemplateArgs = std::move(NewArgs);
5295 class UnnamedLocalNoLinkageFinder
5296 : public TypeVisitor<UnnamedLocalNoLinkageFinder, bool>
5301 typedef TypeVisitor<UnnamedLocalNoLinkageFinder, bool> inherited;
5304 UnnamedLocalNoLinkageFinder(Sema &S, SourceRange SR) : S(S), SR(SR) { }
5306 bool Visit(QualType T) {
5307 return T.isNull() ? false : inherited::Visit(T.getTypePtr());
5310 #define TYPE(Class, Parent) \
5311 bool Visit##Class##Type(const Class##Type *);
5312 #define ABSTRACT_TYPE(Class, Parent) \
5313 bool Visit##Class##Type(const Class##Type *) { return false; }
5314 #define NON_CANONICAL_TYPE(Class, Parent) \
5315 bool Visit##Class##Type(const Class##Type *) { return false; }
5316 #include "clang/AST/TypeNodes.def"
5318 bool VisitTagDecl(const TagDecl *Tag);
5319 bool VisitNestedNameSpecifier(NestedNameSpecifier *NNS);
5321 } // end anonymous namespace
5323 bool UnnamedLocalNoLinkageFinder::VisitBuiltinType(const BuiltinType*) {
5327 bool UnnamedLocalNoLinkageFinder::VisitComplexType(const ComplexType* T) {
5328 return Visit(T->getElementType());
5331 bool UnnamedLocalNoLinkageFinder::VisitPointerType(const PointerType* T) {
5332 return Visit(T->getPointeeType());
5335 bool UnnamedLocalNoLinkageFinder::VisitBlockPointerType(
5336 const BlockPointerType* T) {
5337 return Visit(T->getPointeeType());
5340 bool UnnamedLocalNoLinkageFinder::VisitLValueReferenceType(
5341 const LValueReferenceType* T) {
5342 return Visit(T->getPointeeType());
5345 bool UnnamedLocalNoLinkageFinder::VisitRValueReferenceType(
5346 const RValueReferenceType* T) {
5347 return Visit(T->getPointeeType());
5350 bool UnnamedLocalNoLinkageFinder::VisitMemberPointerType(
5351 const MemberPointerType* T) {
5352 return Visit(T->getPointeeType()) || Visit(QualType(T->getClass(), 0));
5355 bool UnnamedLocalNoLinkageFinder::VisitConstantArrayType(
5356 const ConstantArrayType* T) {
5357 return Visit(T->getElementType());
5360 bool UnnamedLocalNoLinkageFinder::VisitIncompleteArrayType(
5361 const IncompleteArrayType* T) {
5362 return Visit(T->getElementType());
5365 bool UnnamedLocalNoLinkageFinder::VisitVariableArrayType(
5366 const VariableArrayType* T) {
5367 return Visit(T->getElementType());
5370 bool UnnamedLocalNoLinkageFinder::VisitDependentSizedArrayType(
5371 const DependentSizedArrayType* T) {
5372 return Visit(T->getElementType());
5375 bool UnnamedLocalNoLinkageFinder::VisitDependentSizedExtVectorType(
5376 const DependentSizedExtVectorType* T) {
5377 return Visit(T->getElementType());
5380 bool UnnamedLocalNoLinkageFinder::VisitDependentAddressSpaceType(
5381 const DependentAddressSpaceType *T) {
5382 return Visit(T->getPointeeType());
5385 bool UnnamedLocalNoLinkageFinder::VisitVectorType(const VectorType* T) {
5386 return Visit(T->getElementType());
5389 bool UnnamedLocalNoLinkageFinder::VisitDependentVectorType(
5390 const DependentVectorType *T) {
5391 return Visit(T->getElementType());
5394 bool UnnamedLocalNoLinkageFinder::VisitExtVectorType(const ExtVectorType* T) {
5395 return Visit(T->getElementType());
5398 bool UnnamedLocalNoLinkageFinder::VisitFunctionProtoType(
5399 const FunctionProtoType* T) {
5400 for (const auto &A : T->param_types()) {
5405 return Visit(T->getReturnType());
5408 bool UnnamedLocalNoLinkageFinder::VisitFunctionNoProtoType(
5409 const FunctionNoProtoType* T) {
5410 return Visit(T->getReturnType());
5413 bool UnnamedLocalNoLinkageFinder::VisitUnresolvedUsingType(
5414 const UnresolvedUsingType*) {
5418 bool UnnamedLocalNoLinkageFinder::VisitTypeOfExprType(const TypeOfExprType*) {
5422 bool UnnamedLocalNoLinkageFinder::VisitTypeOfType(const TypeOfType* T) {
5423 return Visit(T->getUnderlyingType());
5426 bool UnnamedLocalNoLinkageFinder::VisitDecltypeType(const DecltypeType*) {
5430 bool UnnamedLocalNoLinkageFinder::VisitUnaryTransformType(
5431 const UnaryTransformType*) {
5435 bool UnnamedLocalNoLinkageFinder::VisitAutoType(const AutoType *T) {
5436 return Visit(T->getDeducedType());
5439 bool UnnamedLocalNoLinkageFinder::VisitDeducedTemplateSpecializationType(
5440 const DeducedTemplateSpecializationType *T) {
5441 return Visit(T->getDeducedType());
5444 bool UnnamedLocalNoLinkageFinder::VisitRecordType(const RecordType* T) {
5445 return VisitTagDecl(T->getDecl());
5448 bool UnnamedLocalNoLinkageFinder::VisitEnumType(const EnumType* T) {
5449 return VisitTagDecl(T->getDecl());
5452 bool UnnamedLocalNoLinkageFinder::VisitTemplateTypeParmType(
5453 const TemplateTypeParmType*) {
5457 bool UnnamedLocalNoLinkageFinder::VisitSubstTemplateTypeParmPackType(
5458 const SubstTemplateTypeParmPackType *) {
5462 bool UnnamedLocalNoLinkageFinder::VisitTemplateSpecializationType(
5463 const TemplateSpecializationType*) {
5467 bool UnnamedLocalNoLinkageFinder::VisitInjectedClassNameType(
5468 const InjectedClassNameType* T) {
5469 return VisitTagDecl(T->getDecl());
5472 bool UnnamedLocalNoLinkageFinder::VisitDependentNameType(
5473 const DependentNameType* T) {
5474 return VisitNestedNameSpecifier(T->getQualifier());
5477 bool UnnamedLocalNoLinkageFinder::VisitDependentTemplateSpecializationType(
5478 const DependentTemplateSpecializationType* T) {
5479 return VisitNestedNameSpecifier(T->getQualifier());
5482 bool UnnamedLocalNoLinkageFinder::VisitPackExpansionType(
5483 const PackExpansionType* T) {
5484 return Visit(T->getPattern());
5487 bool UnnamedLocalNoLinkageFinder::VisitObjCObjectType(const ObjCObjectType *) {
5491 bool UnnamedLocalNoLinkageFinder::VisitObjCInterfaceType(
5492 const ObjCInterfaceType *) {
5496 bool UnnamedLocalNoLinkageFinder::VisitObjCObjectPointerType(
5497 const ObjCObjectPointerType *) {
5501 bool UnnamedLocalNoLinkageFinder::VisitAtomicType(const AtomicType* T) {
5502 return Visit(T->getValueType());
5505 bool UnnamedLocalNoLinkageFinder::VisitPipeType(const PipeType* T) {
5509 bool UnnamedLocalNoLinkageFinder::VisitTagDecl(const TagDecl *Tag) {
5510 if (Tag->getDeclContext()->isFunctionOrMethod()) {
5511 S.Diag(SR.getBegin(),
5512 S.getLangOpts().CPlusPlus11 ?
5513 diag::warn_cxx98_compat_template_arg_local_type :
5514 diag::ext_template_arg_local_type)
5515 << S.Context.getTypeDeclType(Tag) << SR;
5519 if (!Tag->hasNameForLinkage()) {
5520 S.Diag(SR.getBegin(),
5521 S.getLangOpts().CPlusPlus11 ?
5522 diag::warn_cxx98_compat_template_arg_unnamed_type :
5523 diag::ext_template_arg_unnamed_type) << SR;
5524 S.Diag(Tag->getLocation(), diag::note_template_unnamed_type_here);
5531 bool UnnamedLocalNoLinkageFinder::VisitNestedNameSpecifier(
5532 NestedNameSpecifier *NNS) {
5533 if (NNS->getPrefix() && VisitNestedNameSpecifier(NNS->getPrefix()))
5536 switch (NNS->getKind()) {
5537 case NestedNameSpecifier::Identifier:
5538 case NestedNameSpecifier::Namespace:
5539 case NestedNameSpecifier::NamespaceAlias:
5540 case NestedNameSpecifier::Global:
5541 case NestedNameSpecifier::Super:
5544 case NestedNameSpecifier::TypeSpec:
5545 case NestedNameSpecifier::TypeSpecWithTemplate:
5546 return Visit(QualType(NNS->getAsType(), 0));
5548 llvm_unreachable("Invalid NestedNameSpecifier::Kind!");
5551 /// Check a template argument against its corresponding
5552 /// template type parameter.
5554 /// This routine implements the semantics of C++ [temp.arg.type]. It
5555 /// returns true if an error occurred, and false otherwise.
5556 bool Sema::CheckTemplateArgument(TemplateTypeParmDecl *Param,
5557 TypeSourceInfo *ArgInfo) {
5558 assert(ArgInfo && "invalid TypeSourceInfo");
5559 QualType Arg = ArgInfo->getType();
5560 SourceRange SR = ArgInfo->getTypeLoc().getSourceRange();
5562 if (Arg->isVariablyModifiedType()) {
5563 return Diag(SR.getBegin(), diag::err_variably_modified_template_arg) << Arg;
5564 } else if (Context.hasSameUnqualifiedType(Arg, Context.OverloadTy)) {
5565 return Diag(SR.getBegin(), diag::err_template_arg_overload_type) << SR;
5568 // C++03 [temp.arg.type]p2:
5569 // A local type, a type with no linkage, an unnamed type or a type
5570 // compounded from any of these types shall not be used as a
5571 // template-argument for a template type-parameter.
5573 // C++11 allows these, and even in C++03 we allow them as an extension with
5575 if (LangOpts.CPlusPlus11 || Arg->hasUnnamedOrLocalType()) {
5576 UnnamedLocalNoLinkageFinder Finder(*this, SR);
5577 (void)Finder.Visit(Context.getCanonicalType(Arg));
5583 enum NullPointerValueKind {
5589 /// Determine whether the given template argument is a null pointer
5590 /// value of the appropriate type.
5591 static NullPointerValueKind
5592 isNullPointerValueTemplateArgument(Sema &S, NonTypeTemplateParmDecl *Param,
5593 QualType ParamType, Expr *Arg,
5594 Decl *Entity = nullptr) {
5595 if (Arg->isValueDependent() || Arg->isTypeDependent())
5596 return NPV_NotNullPointer;
5598 // dllimport'd entities aren't constant but are available inside of template
5600 if (Entity && Entity->hasAttr<DLLImportAttr>())
5601 return NPV_NotNullPointer;
5603 if (!S.isCompleteType(Arg->getExprLoc(), ParamType))
5605 "Incomplete parameter type in isNullPointerValueTemplateArgument!");
5607 if (!S.getLangOpts().CPlusPlus11)
5608 return NPV_NotNullPointer;
5610 // Determine whether we have a constant expression.
5611 ExprResult ArgRV = S.DefaultFunctionArrayConversion(Arg);
5612 if (ArgRV.isInvalid())
5616 Expr::EvalResult EvalResult;
5617 SmallVector<PartialDiagnosticAt, 8> Notes;
5618 EvalResult.Diag = &Notes;
5619 if (!Arg->EvaluateAsRValue(EvalResult, S.Context) ||
5620 EvalResult.HasSideEffects) {
5621 SourceLocation DiagLoc = Arg->getExprLoc();
5623 // If our only note is the usual "invalid subexpression" note, just point
5624 // the caret at its location rather than producing an essentially
5626 if (Notes.size() == 1 && Notes[0].second.getDiagID() ==
5627 diag::note_invalid_subexpr_in_const_expr) {
5628 DiagLoc = Notes[0].first;
5632 S.Diag(DiagLoc, diag::err_template_arg_not_address_constant)
5633 << Arg->getType() << Arg->getSourceRange();
5634 for (unsigned I = 0, N = Notes.size(); I != N; ++I)
5635 S.Diag(Notes[I].first, Notes[I].second);
5637 S.Diag(Param->getLocation(), diag::note_template_param_here);
5641 // C++11 [temp.arg.nontype]p1:
5642 // - an address constant expression of type std::nullptr_t
5643 if (Arg->getType()->isNullPtrType())
5644 return NPV_NullPointer;
5646 // - a constant expression that evaluates to a null pointer value (4.10); or
5647 // - a constant expression that evaluates to a null member pointer value
5649 if ((EvalResult.Val.isLValue() && !EvalResult.Val.getLValueBase()) ||
5650 (EvalResult.Val.isMemberPointer() &&
5651 !EvalResult.Val.getMemberPointerDecl())) {
5652 // If our expression has an appropriate type, we've succeeded.
5653 bool ObjCLifetimeConversion;
5654 if (S.Context.hasSameUnqualifiedType(Arg->getType(), ParamType) ||
5655 S.IsQualificationConversion(Arg->getType(), ParamType, false,
5656 ObjCLifetimeConversion))
5657 return NPV_NullPointer;
5659 // The types didn't match, but we know we got a null pointer; complain,
5660 // then recover as if the types were correct.
5661 S.Diag(Arg->getExprLoc(), diag::err_template_arg_wrongtype_null_constant)
5662 << Arg->getType() << ParamType << Arg->getSourceRange();
5663 S.Diag(Param->getLocation(), diag::note_template_param_here);
5664 return NPV_NullPointer;
5667 // If we don't have a null pointer value, but we do have a NULL pointer
5668 // constant, suggest a cast to the appropriate type.
5669 if (Arg->isNullPointerConstant(S.Context, Expr::NPC_NeverValueDependent)) {
5670 std::string Code = "static_cast<" + ParamType.getAsString() + ">(";
5671 S.Diag(Arg->getExprLoc(), diag::err_template_arg_untyped_null_constant)
5672 << ParamType << FixItHint::CreateInsertion(Arg->getBeginLoc(), Code)
5673 << FixItHint::CreateInsertion(S.getLocForEndOfToken(Arg->getEndLoc()),
5675 S.Diag(Param->getLocation(), diag::note_template_param_here);
5676 return NPV_NullPointer;
5679 // FIXME: If we ever want to support general, address-constant expressions
5680 // as non-type template arguments, we should return the ExprResult here to
5681 // be interpreted by the caller.
5682 return NPV_NotNullPointer;
5685 /// Checks whether the given template argument is compatible with its
5686 /// template parameter.
5687 static bool CheckTemplateArgumentIsCompatibleWithParameter(
5688 Sema &S, NonTypeTemplateParmDecl *Param, QualType ParamType, Expr *ArgIn,
5689 Expr *Arg, QualType ArgType) {
5690 bool ObjCLifetimeConversion;
5691 if (ParamType->isPointerType() &&
5692 !ParamType->getAs<PointerType>()->getPointeeType()->isFunctionType() &&
5693 S.IsQualificationConversion(ArgType, ParamType, false,
5694 ObjCLifetimeConversion)) {
5695 // For pointer-to-object types, qualification conversions are
5698 if (const ReferenceType *ParamRef = ParamType->getAs<ReferenceType>()) {
5699 if (!ParamRef->getPointeeType()->isFunctionType()) {
5700 // C++ [temp.arg.nontype]p5b3:
5701 // For a non-type template-parameter of type reference to
5702 // object, no conversions apply. The type referred to by the
5703 // reference may be more cv-qualified than the (otherwise
5704 // identical) type of the template- argument. The
5705 // template-parameter is bound directly to the
5706 // template-argument, which shall be an lvalue.
5708 // FIXME: Other qualifiers?
5709 unsigned ParamQuals = ParamRef->getPointeeType().getCVRQualifiers();
5710 unsigned ArgQuals = ArgType.getCVRQualifiers();
5712 if ((ParamQuals | ArgQuals) != ParamQuals) {
5713 S.Diag(Arg->getBeginLoc(),
5714 diag::err_template_arg_ref_bind_ignores_quals)
5715 << ParamType << Arg->getType() << Arg->getSourceRange();
5716 S.Diag(Param->getLocation(), diag::note_template_param_here);
5722 // At this point, the template argument refers to an object or
5723 // function with external linkage. We now need to check whether the
5724 // argument and parameter types are compatible.
5725 if (!S.Context.hasSameUnqualifiedType(ArgType,
5726 ParamType.getNonReferenceType())) {
5727 // We can't perform this conversion or binding.
5728 if (ParamType->isReferenceType())
5729 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_no_ref_bind)
5730 << ParamType << ArgIn->getType() << Arg->getSourceRange();
5732 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_not_convertible)
5733 << ArgIn->getType() << ParamType << Arg->getSourceRange();
5734 S.Diag(Param->getLocation(), diag::note_template_param_here);
5742 /// Checks whether the given template argument is the address
5743 /// of an object or function according to C++ [temp.arg.nontype]p1.
5745 CheckTemplateArgumentAddressOfObjectOrFunction(Sema &S,
5746 NonTypeTemplateParmDecl *Param,
5749 TemplateArgument &Converted) {
5750 bool Invalid = false;
5752 QualType ArgType = Arg->getType();
5754 bool AddressTaken = false;
5755 SourceLocation AddrOpLoc;
5756 if (S.getLangOpts().MicrosoftExt) {
5757 // Microsoft Visual C++ strips all casts, allows an arbitrary number of
5758 // dereference and address-of operators.
5759 Arg = Arg->IgnoreParenCasts();
5761 bool ExtWarnMSTemplateArg = false;
5762 UnaryOperatorKind FirstOpKind;
5763 SourceLocation FirstOpLoc;
5764 while (UnaryOperator *UnOp = dyn_cast<UnaryOperator>(Arg)) {
5765 UnaryOperatorKind UnOpKind = UnOp->getOpcode();
5766 if (UnOpKind == UO_Deref)
5767 ExtWarnMSTemplateArg = true;
5768 if (UnOpKind == UO_AddrOf || UnOpKind == UO_Deref) {
5769 Arg = UnOp->getSubExpr()->IgnoreParenCasts();
5770 if (!AddrOpLoc.isValid()) {
5771 FirstOpKind = UnOpKind;
5772 FirstOpLoc = UnOp->getOperatorLoc();
5777 if (FirstOpLoc.isValid()) {
5778 if (ExtWarnMSTemplateArg)
5779 S.Diag(ArgIn->getBeginLoc(), diag::ext_ms_deref_template_argument)
5780 << ArgIn->getSourceRange();
5782 if (FirstOpKind == UO_AddrOf)
5783 AddressTaken = true;
5784 else if (Arg->getType()->isPointerType()) {
5785 // We cannot let pointers get dereferenced here, that is obviously not a
5786 // constant expression.
5787 assert(FirstOpKind == UO_Deref);
5788 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_not_decl_ref)
5789 << Arg->getSourceRange();
5793 // See through any implicit casts we added to fix the type.
5794 Arg = Arg->IgnoreImpCasts();
5796 // C++ [temp.arg.nontype]p1:
5798 // A template-argument for a non-type, non-template
5799 // template-parameter shall be one of: [...]
5801 // -- the address of an object or function with external
5802 // linkage, including function templates and function
5803 // template-ids but excluding non-static class members,
5804 // expressed as & id-expression where the & is optional if
5805 // the name refers to a function or array, or if the
5806 // corresponding template-parameter is a reference; or
5808 // In C++98/03 mode, give an extension warning on any extra parentheses.
5809 // See http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#773
5810 bool ExtraParens = false;
5811 while (ParenExpr *Parens = dyn_cast<ParenExpr>(Arg)) {
5812 if (!Invalid && !ExtraParens) {
5813 S.Diag(Arg->getBeginLoc(),
5814 S.getLangOpts().CPlusPlus11
5815 ? diag::warn_cxx98_compat_template_arg_extra_parens
5816 : diag::ext_template_arg_extra_parens)
5817 << Arg->getSourceRange();
5821 Arg = Parens->getSubExpr();
5824 while (SubstNonTypeTemplateParmExpr *subst =
5825 dyn_cast<SubstNonTypeTemplateParmExpr>(Arg))
5826 Arg = subst->getReplacement()->IgnoreImpCasts();
5828 if (UnaryOperator *UnOp = dyn_cast<UnaryOperator>(Arg)) {
5829 if (UnOp->getOpcode() == UO_AddrOf) {
5830 Arg = UnOp->getSubExpr();
5831 AddressTaken = true;
5832 AddrOpLoc = UnOp->getOperatorLoc();
5836 while (SubstNonTypeTemplateParmExpr *subst =
5837 dyn_cast<SubstNonTypeTemplateParmExpr>(Arg))
5838 Arg = subst->getReplacement()->IgnoreImpCasts();
5841 DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Arg);
5842 ValueDecl *Entity = DRE ? DRE->getDecl() : nullptr;
5844 // If our parameter has pointer type, check for a null template value.
5845 if (ParamType->isPointerType() || ParamType->isNullPtrType()) {
5846 switch (isNullPointerValueTemplateArgument(S, Param, ParamType, ArgIn,
5848 case NPV_NullPointer:
5849 S.Diag(Arg->getExprLoc(), diag::warn_cxx98_compat_template_arg_null);
5850 Converted = TemplateArgument(S.Context.getCanonicalType(ParamType),
5851 /*isNullPtr=*/true);
5857 case NPV_NotNullPointer:
5862 // Stop checking the precise nature of the argument if it is value dependent,
5863 // it should be checked when instantiated.
5864 if (Arg->isValueDependent()) {
5865 Converted = TemplateArgument(ArgIn);
5869 if (isa<CXXUuidofExpr>(Arg)) {
5870 if (CheckTemplateArgumentIsCompatibleWithParameter(S, Param, ParamType,
5871 ArgIn, Arg, ArgType))
5874 Converted = TemplateArgument(ArgIn);
5879 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_not_decl_ref)
5880 << Arg->getSourceRange();
5881 S.Diag(Param->getLocation(), diag::note_template_param_here);
5885 // Cannot refer to non-static data members
5886 if (isa<FieldDecl>(Entity) || isa<IndirectFieldDecl>(Entity)) {
5887 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_field)
5888 << Entity << Arg->getSourceRange();
5889 S.Diag(Param->getLocation(), diag::note_template_param_here);
5893 // Cannot refer to non-static member functions
5894 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Entity)) {
5895 if (!Method->isStatic()) {
5896 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_method)
5897 << Method << Arg->getSourceRange();
5898 S.Diag(Param->getLocation(), diag::note_template_param_here);
5903 FunctionDecl *Func = dyn_cast<FunctionDecl>(Entity);
5904 VarDecl *Var = dyn_cast<VarDecl>(Entity);
5906 // A non-type template argument must refer to an object or function.
5907 if (!Func && !Var) {
5908 // We found something, but we don't know specifically what it is.
5909 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_not_object_or_func)
5910 << Arg->getSourceRange();
5911 S.Diag(DRE->getDecl()->getLocation(), diag::note_template_arg_refers_here);
5915 // Address / reference template args must have external linkage in C++98.
5916 if (Entity->getFormalLinkage() == InternalLinkage) {
5917 S.Diag(Arg->getBeginLoc(),
5918 S.getLangOpts().CPlusPlus11
5919 ? diag::warn_cxx98_compat_template_arg_object_internal
5920 : diag::ext_template_arg_object_internal)
5921 << !Func << Entity << Arg->getSourceRange();
5922 S.Diag(Entity->getLocation(), diag::note_template_arg_internal_object)
5924 } else if (!Entity->hasLinkage()) {
5925 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_object_no_linkage)
5926 << !Func << Entity << Arg->getSourceRange();
5927 S.Diag(Entity->getLocation(), diag::note_template_arg_internal_object)
5933 // If the template parameter has pointer type, the function decays.
5934 if (ParamType->isPointerType() && !AddressTaken)
5935 ArgType = S.Context.getPointerType(Func->getType());
5936 else if (AddressTaken && ParamType->isReferenceType()) {
5937 // If we originally had an address-of operator, but the
5938 // parameter has reference type, complain and (if things look
5939 // like they will work) drop the address-of operator.
5940 if (!S.Context.hasSameUnqualifiedType(Func->getType(),
5941 ParamType.getNonReferenceType())) {
5942 S.Diag(AddrOpLoc, diag::err_template_arg_address_of_non_pointer)
5944 S.Diag(Param->getLocation(), diag::note_template_param_here);
5948 S.Diag(AddrOpLoc, diag::err_template_arg_address_of_non_pointer)
5950 << FixItHint::CreateRemoval(AddrOpLoc);
5951 S.Diag(Param->getLocation(), diag::note_template_param_here);
5953 ArgType = Func->getType();
5956 // A value of reference type is not an object.
5957 if (Var->getType()->isReferenceType()) {
5958 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_reference_var)
5959 << Var->getType() << Arg->getSourceRange();
5960 S.Diag(Param->getLocation(), diag::note_template_param_here);
5964 // A template argument must have static storage duration.
5965 if (Var->getTLSKind()) {
5966 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_thread_local)
5967 << Arg->getSourceRange();
5968 S.Diag(Var->getLocation(), diag::note_template_arg_refers_here);
5972 // If the template parameter has pointer type, we must have taken
5973 // the address of this object.
5974 if (ParamType->isReferenceType()) {
5976 // If we originally had an address-of operator, but the
5977 // parameter has reference type, complain and (if things look
5978 // like they will work) drop the address-of operator.
5979 if (!S.Context.hasSameUnqualifiedType(Var->getType(),
5980 ParamType.getNonReferenceType())) {
5981 S.Diag(AddrOpLoc, diag::err_template_arg_address_of_non_pointer)
5983 S.Diag(Param->getLocation(), diag::note_template_param_here);
5987 S.Diag(AddrOpLoc, diag::err_template_arg_address_of_non_pointer)
5989 << FixItHint::CreateRemoval(AddrOpLoc);
5990 S.Diag(Param->getLocation(), diag::note_template_param_here);
5992 ArgType = Var->getType();
5994 } else if (!AddressTaken && ParamType->isPointerType()) {
5995 if (Var->getType()->isArrayType()) {
5996 // Array-to-pointer decay.
5997 ArgType = S.Context.getArrayDecayedType(Var->getType());
5999 // If the template parameter has pointer type but the address of
6000 // this object was not taken, complain and (possibly) recover by
6001 // taking the address of the entity.
6002 ArgType = S.Context.getPointerType(Var->getType());
6003 if (!S.Context.hasSameUnqualifiedType(ArgType, ParamType)) {
6004 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_not_address_of)
6006 S.Diag(Param->getLocation(), diag::note_template_param_here);
6010 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_not_address_of)
6011 << ParamType << FixItHint::CreateInsertion(Arg->getBeginLoc(), "&");
6013 S.Diag(Param->getLocation(), diag::note_template_param_here);
6018 if (CheckTemplateArgumentIsCompatibleWithParameter(S, Param, ParamType, ArgIn,
6022 // Create the template argument.
6024 TemplateArgument(cast<ValueDecl>(Entity->getCanonicalDecl()), ParamType);
6025 S.MarkAnyDeclReferenced(Arg->getBeginLoc(), Entity, false);
6029 /// Checks whether the given template argument is a pointer to
6030 /// member constant according to C++ [temp.arg.nontype]p1.
6031 static bool CheckTemplateArgumentPointerToMember(Sema &S,
6032 NonTypeTemplateParmDecl *Param,
6035 TemplateArgument &Converted) {
6036 bool Invalid = false;
6038 Expr *Arg = ResultArg;
6039 bool ObjCLifetimeConversion;
6041 // C++ [temp.arg.nontype]p1:
6043 // A template-argument for a non-type, non-template
6044 // template-parameter shall be one of: [...]
6046 // -- a pointer to member expressed as described in 5.3.1.
6047 DeclRefExpr *DRE = nullptr;
6049 // In C++98/03 mode, give an extension warning on any extra parentheses.
6050 // See http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#773
6051 bool ExtraParens = false;
6052 while (ParenExpr *Parens = dyn_cast<ParenExpr>(Arg)) {
6053 if (!Invalid && !ExtraParens) {
6054 S.Diag(Arg->getBeginLoc(),
6055 S.getLangOpts().CPlusPlus11
6056 ? diag::warn_cxx98_compat_template_arg_extra_parens
6057 : diag::ext_template_arg_extra_parens)
6058 << Arg->getSourceRange();
6062 Arg = Parens->getSubExpr();
6065 while (SubstNonTypeTemplateParmExpr *subst =
6066 dyn_cast<SubstNonTypeTemplateParmExpr>(Arg))
6067 Arg = subst->getReplacement()->IgnoreImpCasts();
6069 // A pointer-to-member constant written &Class::member.
6070 if (UnaryOperator *UnOp = dyn_cast<UnaryOperator>(Arg)) {
6071 if (UnOp->getOpcode() == UO_AddrOf) {
6072 DRE = dyn_cast<DeclRefExpr>(UnOp->getSubExpr());
6073 if (DRE && !DRE->getQualifier())
6077 // A constant of pointer-to-member type.
6078 else if ((DRE = dyn_cast<DeclRefExpr>(Arg))) {
6079 ValueDecl *VD = DRE->getDecl();
6080 if (VD->getType()->isMemberPointerType()) {
6081 if (isa<NonTypeTemplateParmDecl>(VD)) {
6082 if (Arg->isTypeDependent() || Arg->isValueDependent()) {
6083 Converted = TemplateArgument(Arg);
6085 VD = cast<ValueDecl>(VD->getCanonicalDecl());
6086 Converted = TemplateArgument(VD, ParamType);
6095 ValueDecl *Entity = DRE ? DRE->getDecl() : nullptr;
6097 // Check for a null pointer value.
6098 switch (isNullPointerValueTemplateArgument(S, Param, ParamType, ResultArg,
6102 case NPV_NullPointer:
6103 S.Diag(ResultArg->getExprLoc(), diag::warn_cxx98_compat_template_arg_null);
6104 Converted = TemplateArgument(S.Context.getCanonicalType(ParamType),
6107 case NPV_NotNullPointer:
6111 if (S.IsQualificationConversion(ResultArg->getType(),
6112 ParamType.getNonReferenceType(), false,
6113 ObjCLifetimeConversion)) {
6114 ResultArg = S.ImpCastExprToType(ResultArg, ParamType, CK_NoOp,
6115 ResultArg->getValueKind())
6117 } else if (!S.Context.hasSameUnqualifiedType(
6118 ResultArg->getType(), ParamType.getNonReferenceType())) {
6119 // We can't perform this conversion.
6120 S.Diag(ResultArg->getBeginLoc(), diag::err_template_arg_not_convertible)
6121 << ResultArg->getType() << ParamType << ResultArg->getSourceRange();
6122 S.Diag(Param->getLocation(), diag::note_template_param_here);
6127 return S.Diag(Arg->getBeginLoc(),
6128 diag::err_template_arg_not_pointer_to_member_form)
6129 << Arg->getSourceRange();
6131 if (isa<FieldDecl>(DRE->getDecl()) ||
6132 isa<IndirectFieldDecl>(DRE->getDecl()) ||
6133 isa<CXXMethodDecl>(DRE->getDecl())) {
6134 assert((isa<FieldDecl>(DRE->getDecl()) ||
6135 isa<IndirectFieldDecl>(DRE->getDecl()) ||
6136 !cast<CXXMethodDecl>(DRE->getDecl())->isStatic()) &&
6137 "Only non-static member pointers can make it here");
6139 // Okay: this is the address of a non-static member, and therefore
6140 // a member pointer constant.
6141 if (Arg->isTypeDependent() || Arg->isValueDependent()) {
6142 Converted = TemplateArgument(Arg);
6144 ValueDecl *D = cast<ValueDecl>(DRE->getDecl()->getCanonicalDecl());
6145 Converted = TemplateArgument(D, ParamType);
6150 // We found something else, but we don't know specifically what it is.
6151 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_not_pointer_to_member_form)
6152 << Arg->getSourceRange();
6153 S.Diag(DRE->getDecl()->getLocation(), diag::note_template_arg_refers_here);
6157 /// Check a template argument against its corresponding
6158 /// non-type template parameter.
6160 /// This routine implements the semantics of C++ [temp.arg.nontype].
6161 /// If an error occurred, it returns ExprError(); otherwise, it
6162 /// returns the converted template argument. \p ParamType is the
6163 /// type of the non-type template parameter after it has been instantiated.
6164 ExprResult Sema::CheckTemplateArgument(NonTypeTemplateParmDecl *Param,
6165 QualType ParamType, Expr *Arg,
6166 TemplateArgument &Converted,
6167 CheckTemplateArgumentKind CTAK) {
6168 SourceLocation StartLoc = Arg->getBeginLoc();
6170 // If the parameter type somehow involves auto, deduce the type now.
6171 if (getLangOpts().CPlusPlus17 && ParamType->isUndeducedType()) {
6172 // During template argument deduction, we allow 'decltype(auto)' to
6173 // match an arbitrary dependent argument.
6174 // FIXME: The language rules don't say what happens in this case.
6175 // FIXME: We get an opaque dependent type out of decltype(auto) if the
6176 // expression is merely instantiation-dependent; is this enough?
6177 if (CTAK == CTAK_Deduced && Arg->isTypeDependent()) {
6178 auto *AT = dyn_cast<AutoType>(ParamType);
6179 if (AT && AT->isDecltypeAuto()) {
6180 Converted = TemplateArgument(Arg);
6185 // When checking a deduced template argument, deduce from its type even if
6186 // the type is dependent, in order to check the types of non-type template
6187 // arguments line up properly in partial ordering.
6188 Optional<unsigned> Depth;
6189 if (CTAK != CTAK_Specified)
6190 Depth = Param->getDepth() + 1;
6192 Context.getTrivialTypeSourceInfo(ParamType, Param->getLocation()),
6193 Arg, ParamType, Depth) == DAR_Failed) {
6194 Diag(Arg->getExprLoc(),
6195 diag::err_non_type_template_parm_type_deduction_failure)
6196 << Param->getDeclName() << Param->getType() << Arg->getType()
6197 << Arg->getSourceRange();
6198 Diag(Param->getLocation(), diag::note_template_param_here);
6201 // CheckNonTypeTemplateParameterType will produce a diagnostic if there's
6202 // an error. The error message normally references the parameter
6203 // declaration, but here we'll pass the argument location because that's
6204 // where the parameter type is deduced.
6205 ParamType = CheckNonTypeTemplateParameterType(ParamType, Arg->getExprLoc());
6206 if (ParamType.isNull()) {
6207 Diag(Param->getLocation(), diag::note_template_param_here);
6212 // We should have already dropped all cv-qualifiers by now.
6213 assert(!ParamType.hasQualifiers() &&
6214 "non-type template parameter type cannot be qualified");
6216 if (CTAK == CTAK_Deduced &&
6217 !Context.hasSameType(ParamType.getNonLValueExprType(Context),
6219 // FIXME: If either type is dependent, we skip the check. This isn't
6220 // correct, since during deduction we're supposed to have replaced each
6221 // template parameter with some unique (non-dependent) placeholder.
6222 // FIXME: If the argument type contains 'auto', we carry on and fail the
6223 // type check in order to force specific types to be more specialized than
6224 // 'auto'. It's not clear how partial ordering with 'auto' is supposed to
6226 if ((ParamType->isDependentType() || Arg->isTypeDependent()) &&
6227 !Arg->getType()->getContainedAutoType()) {
6228 Converted = TemplateArgument(Arg);
6231 // FIXME: This attempts to implement C++ [temp.deduct.type]p17. Per DR1770,
6232 // we should actually be checking the type of the template argument in P,
6233 // not the type of the template argument deduced from A, against the
6234 // template parameter type.
6235 Diag(StartLoc, diag::err_deduced_non_type_template_arg_type_mismatch)
6237 << ParamType.getUnqualifiedType();
6238 Diag(Param->getLocation(), diag::note_template_param_here);
6242 // If either the parameter has a dependent type or the argument is
6243 // type-dependent, there's nothing we can check now.
6244 if (ParamType->isDependentType() || Arg->isTypeDependent()) {
6245 // FIXME: Produce a cloned, canonical expression?
6246 Converted = TemplateArgument(Arg);
6250 // The initialization of the parameter from the argument is
6251 // a constant-evaluated context.
6252 EnterExpressionEvaluationContext ConstantEvaluated(
6253 *this, Sema::ExpressionEvaluationContext::ConstantEvaluated);
6255 if (getLangOpts().CPlusPlus17) {
6256 // C++17 [temp.arg.nontype]p1:
6257 // A template-argument for a non-type template parameter shall be
6258 // a converted constant expression of the type of the template-parameter.
6260 ExprResult ArgResult = CheckConvertedConstantExpression(
6261 Arg, ParamType, Value, CCEK_TemplateArg);
6262 if (ArgResult.isInvalid())
6265 // For a value-dependent argument, CheckConvertedConstantExpression is
6266 // permitted (and expected) to be unable to determine a value.
6267 if (ArgResult.get()->isValueDependent()) {
6268 Converted = TemplateArgument(ArgResult.get());
6272 QualType CanonParamType = Context.getCanonicalType(ParamType);
6274 // Convert the APValue to a TemplateArgument.
6275 switch (Value.getKind()) {
6276 case APValue::Uninitialized:
6277 assert(ParamType->isNullPtrType());
6278 Converted = TemplateArgument(CanonParamType, /*isNullPtr*/true);
6281 assert(ParamType->isIntegralOrEnumerationType());
6282 Converted = TemplateArgument(Context, Value.getInt(), CanonParamType);
6284 case APValue::MemberPointer: {
6285 assert(ParamType->isMemberPointerType());
6287 // FIXME: We need TemplateArgument representation and mangling for these.
6288 if (!Value.getMemberPointerPath().empty()) {
6289 Diag(Arg->getBeginLoc(),
6290 diag::err_template_arg_member_ptr_base_derived_not_supported)
6291 << Value.getMemberPointerDecl() << ParamType
6292 << Arg->getSourceRange();
6296 auto *VD = const_cast<ValueDecl*>(Value.getMemberPointerDecl());
6297 Converted = VD ? TemplateArgument(VD, CanonParamType)
6298 : TemplateArgument(CanonParamType, /*isNullPtr*/true);
6301 case APValue::LValue: {
6302 // For a non-type template-parameter of pointer or reference type,
6303 // the value of the constant expression shall not refer to
6304 assert(ParamType->isPointerType() || ParamType->isReferenceType() ||
6305 ParamType->isNullPtrType());
6306 // -- a temporary object
6307 // -- a string literal
6308 // -- the result of a typeid expression, or
6309 // -- a predefined __func__ variable
6310 if (auto *E = Value.getLValueBase().dyn_cast<const Expr*>()) {
6311 if (isa<CXXUuidofExpr>(E)) {
6312 Converted = TemplateArgument(ArgResult.get()->IgnoreImpCasts());
6315 Diag(Arg->getBeginLoc(), diag::err_template_arg_not_decl_ref)
6316 << Arg->getSourceRange();
6319 auto *VD = const_cast<ValueDecl *>(
6320 Value.getLValueBase().dyn_cast<const ValueDecl *>());
6322 if (Value.hasLValuePath() && Value.getLValuePath().size() == 1 &&
6323 VD && VD->getType()->isArrayType() &&
6324 Value.getLValuePath()[0].ArrayIndex == 0 &&
6325 !Value.isLValueOnePastTheEnd() && ParamType->isPointerType()) {
6326 // Per defect report (no number yet):
6327 // ... other than a pointer to the first element of a complete array
6329 } else if (!Value.hasLValuePath() || Value.getLValuePath().size() ||
6330 Value.isLValueOnePastTheEnd()) {
6331 Diag(StartLoc, diag::err_non_type_template_arg_subobject)
6332 << Value.getAsString(Context, ParamType);
6335 assert((VD || !ParamType->isReferenceType()) &&
6336 "null reference should not be a constant expression");
6337 assert((!VD || !ParamType->isNullPtrType()) &&
6338 "non-null value of type nullptr_t?");
6339 Converted = VD ? TemplateArgument(VD, CanonParamType)
6340 : TemplateArgument(CanonParamType, /*isNullPtr*/true);
6343 case APValue::AddrLabelDiff:
6344 return Diag(StartLoc, diag::err_non_type_template_arg_addr_label_diff);
6345 case APValue::Float:
6346 case APValue::ComplexInt:
6347 case APValue::ComplexFloat:
6348 case APValue::Vector:
6349 case APValue::Array:
6350 case APValue::Struct:
6351 case APValue::Union:
6352 llvm_unreachable("invalid kind for template argument");
6355 return ArgResult.get();
6358 // C++ [temp.arg.nontype]p5:
6359 // The following conversions are performed on each expression used
6360 // as a non-type template-argument. If a non-type
6361 // template-argument cannot be converted to the type of the
6362 // corresponding template-parameter then the program is
6364 if (ParamType->isIntegralOrEnumerationType()) {
6366 // -- for a non-type template-parameter of integral or
6367 // enumeration type, conversions permitted in a converted
6368 // constant expression are applied.
6371 // -- for a non-type template-parameter of integral or
6372 // enumeration type, integral promotions (4.5) and integral
6373 // conversions (4.7) are applied.
6375 if (getLangOpts().CPlusPlus11) {
6376 // C++ [temp.arg.nontype]p1:
6377 // A template-argument for a non-type, non-template template-parameter
6380 // -- for a non-type template-parameter of integral or enumeration
6381 // type, a converted constant expression of the type of the
6382 // template-parameter; or
6384 ExprResult ArgResult =
6385 CheckConvertedConstantExpression(Arg, ParamType, Value,
6387 if (ArgResult.isInvalid())
6390 // We can't check arbitrary value-dependent arguments.
6391 if (ArgResult.get()->isValueDependent()) {
6392 Converted = TemplateArgument(ArgResult.get());
6396 // Widen the argument value to sizeof(parameter type). This is almost
6397 // always a no-op, except when the parameter type is bool. In
6398 // that case, this may extend the argument from 1 bit to 8 bits.
6399 QualType IntegerType = ParamType;
6400 if (const EnumType *Enum = IntegerType->getAs<EnumType>())
6401 IntegerType = Enum->getDecl()->getIntegerType();
6402 Value = Value.extOrTrunc(Context.getTypeSize(IntegerType));
6404 Converted = TemplateArgument(Context, Value,
6405 Context.getCanonicalType(ParamType));
6409 ExprResult ArgResult = DefaultLvalueConversion(Arg);
6410 if (ArgResult.isInvalid())
6412 Arg = ArgResult.get();
6414 QualType ArgType = Arg->getType();
6416 // C++ [temp.arg.nontype]p1:
6417 // A template-argument for a non-type, non-template
6418 // template-parameter shall be one of:
6420 // -- an integral constant-expression of integral or enumeration
6422 // -- the name of a non-type template-parameter; or
6424 if (!ArgType->isIntegralOrEnumerationType()) {
6425 Diag(Arg->getBeginLoc(), diag::err_template_arg_not_integral_or_enumeral)
6426 << ArgType << Arg->getSourceRange();
6427 Diag(Param->getLocation(), diag::note_template_param_here);
6429 } else if (!Arg->isValueDependent()) {
6430 class TmplArgICEDiagnoser : public VerifyICEDiagnoser {
6434 TmplArgICEDiagnoser(QualType T) : T(T) { }
6436 void diagnoseNotICE(Sema &S, SourceLocation Loc,
6437 SourceRange SR) override {
6438 S.Diag(Loc, diag::err_template_arg_not_ice) << T << SR;
6440 } Diagnoser(ArgType);
6442 Arg = VerifyIntegerConstantExpression(Arg, &Value, Diagnoser,
6448 // From here on out, all we care about is the unqualified form
6449 // of the argument type.
6450 ArgType = ArgType.getUnqualifiedType();
6452 // Try to convert the argument to the parameter's type.
6453 if (Context.hasSameType(ParamType, ArgType)) {
6454 // Okay: no conversion necessary
6455 } else if (ParamType->isBooleanType()) {
6456 // This is an integral-to-boolean conversion.
6457 Arg = ImpCastExprToType(Arg, ParamType, CK_IntegralToBoolean).get();
6458 } else if (IsIntegralPromotion(Arg, ArgType, ParamType) ||
6459 !ParamType->isEnumeralType()) {
6460 // This is an integral promotion or conversion.
6461 Arg = ImpCastExprToType(Arg, ParamType, CK_IntegralCast).get();
6463 // We can't perform this conversion.
6464 Diag(Arg->getBeginLoc(), diag::err_template_arg_not_convertible)
6465 << Arg->getType() << ParamType << Arg->getSourceRange();
6466 Diag(Param->getLocation(), diag::note_template_param_here);
6470 // Add the value of this argument to the list of converted
6471 // arguments. We use the bitwidth and signedness of the template
6473 if (Arg->isValueDependent()) {
6474 // The argument is value-dependent. Create a new
6475 // TemplateArgument with the converted expression.
6476 Converted = TemplateArgument(Arg);
6480 QualType IntegerType = Context.getCanonicalType(ParamType);
6481 if (const EnumType *Enum = IntegerType->getAs<EnumType>())
6482 IntegerType = Context.getCanonicalType(Enum->getDecl()->getIntegerType());
6484 if (ParamType->isBooleanType()) {
6485 // Value must be zero or one.
6487 unsigned AllowedBits = Context.getTypeSize(IntegerType);
6488 if (Value.getBitWidth() != AllowedBits)
6489 Value = Value.extOrTrunc(AllowedBits);
6490 Value.setIsSigned(IntegerType->isSignedIntegerOrEnumerationType());
6492 llvm::APSInt OldValue = Value;
6494 // Coerce the template argument's value to the value it will have
6495 // based on the template parameter's type.
6496 unsigned AllowedBits = Context.getTypeSize(IntegerType);
6497 if (Value.getBitWidth() != AllowedBits)
6498 Value = Value.extOrTrunc(AllowedBits);
6499 Value.setIsSigned(IntegerType->isSignedIntegerOrEnumerationType());
6501 // Complain if an unsigned parameter received a negative value.
6502 if (IntegerType->isUnsignedIntegerOrEnumerationType()
6503 && (OldValue.isSigned() && OldValue.isNegative())) {
6504 Diag(Arg->getBeginLoc(), diag::warn_template_arg_negative)
6505 << OldValue.toString(10) << Value.toString(10) << Param->getType()
6506 << Arg->getSourceRange();
6507 Diag(Param->getLocation(), diag::note_template_param_here);
6510 // Complain if we overflowed the template parameter's type.
6511 unsigned RequiredBits;
6512 if (IntegerType->isUnsignedIntegerOrEnumerationType())
6513 RequiredBits = OldValue.getActiveBits();
6514 else if (OldValue.isUnsigned())
6515 RequiredBits = OldValue.getActiveBits() + 1;
6517 RequiredBits = OldValue.getMinSignedBits();
6518 if (RequiredBits > AllowedBits) {
6519 Diag(Arg->getBeginLoc(), diag::warn_template_arg_too_large)
6520 << OldValue.toString(10) << Value.toString(10) << Param->getType()
6521 << Arg->getSourceRange();
6522 Diag(Param->getLocation(), diag::note_template_param_here);
6526 Converted = TemplateArgument(Context, Value,
6527 ParamType->isEnumeralType()
6528 ? Context.getCanonicalType(ParamType)
6533 QualType ArgType = Arg->getType();
6534 DeclAccessPair FoundResult; // temporary for ResolveOverloadedFunction
6536 // Handle pointer-to-function, reference-to-function, and
6537 // pointer-to-member-function all in (roughly) the same way.
6538 if (// -- For a non-type template-parameter of type pointer to
6539 // function, only the function-to-pointer conversion (4.3) is
6540 // applied. If the template-argument represents a set of
6541 // overloaded functions (or a pointer to such), the matching
6542 // function is selected from the set (13.4).
6543 (ParamType->isPointerType() &&
6544 ParamType->getAs<PointerType>()->getPointeeType()->isFunctionType()) ||
6545 // -- For a non-type template-parameter of type reference to
6546 // function, no conversions apply. If the template-argument
6547 // represents a set of overloaded functions, the matching
6548 // function is selected from the set (13.4).
6549 (ParamType->isReferenceType() &&
6550 ParamType->getAs<ReferenceType>()->getPointeeType()->isFunctionType()) ||
6551 // -- For a non-type template-parameter of type pointer to
6552 // member function, no conversions apply. If the
6553 // template-argument represents a set of overloaded member
6554 // functions, the matching member function is selected from
6556 (ParamType->isMemberPointerType() &&
6557 ParamType->getAs<MemberPointerType>()->getPointeeType()
6558 ->isFunctionType())) {
6560 if (Arg->getType() == Context.OverloadTy) {
6561 if (FunctionDecl *Fn = ResolveAddressOfOverloadedFunction(Arg, ParamType,
6564 if (DiagnoseUseOfDecl(Fn, Arg->getBeginLoc()))
6567 Arg = FixOverloadedFunctionReference(Arg, FoundResult, Fn);
6568 ArgType = Arg->getType();
6573 if (!ParamType->isMemberPointerType()) {
6574 if (CheckTemplateArgumentAddressOfObjectOrFunction(*this, Param,
6581 if (CheckTemplateArgumentPointerToMember(*this, Param, ParamType, Arg,
6587 if (ParamType->isPointerType()) {
6588 // -- for a non-type template-parameter of type pointer to
6589 // object, qualification conversions (4.4) and the
6590 // array-to-pointer conversion (4.2) are applied.
6591 // C++0x also allows a value of std::nullptr_t.
6592 assert(ParamType->getPointeeType()->isIncompleteOrObjectType() &&
6593 "Only object pointers allowed here");
6595 if (CheckTemplateArgumentAddressOfObjectOrFunction(*this, Param,
6602 if (const ReferenceType *ParamRefType = ParamType->getAs<ReferenceType>()) {
6603 // -- For a non-type template-parameter of type reference to
6604 // object, no conversions apply. The type referred to by the
6605 // reference may be more cv-qualified than the (otherwise
6606 // identical) type of the template-argument. The
6607 // template-parameter is bound directly to the
6608 // template-argument, which must be an lvalue.
6609 assert(ParamRefType->getPointeeType()->isIncompleteOrObjectType() &&
6610 "Only object references allowed here");
6612 if (Arg->getType() == Context.OverloadTy) {
6613 if (FunctionDecl *Fn = ResolveAddressOfOverloadedFunction(Arg,
6614 ParamRefType->getPointeeType(),
6617 if (DiagnoseUseOfDecl(Fn, Arg->getBeginLoc()))
6620 Arg = FixOverloadedFunctionReference(Arg, FoundResult, Fn);
6621 ArgType = Arg->getType();
6626 if (CheckTemplateArgumentAddressOfObjectOrFunction(*this, Param,
6633 // Deal with parameters of type std::nullptr_t.
6634 if (ParamType->isNullPtrType()) {
6635 if (Arg->isTypeDependent() || Arg->isValueDependent()) {
6636 Converted = TemplateArgument(Arg);
6640 switch (isNullPointerValueTemplateArgument(*this, Param, ParamType, Arg)) {
6641 case NPV_NotNullPointer:
6642 Diag(Arg->getExprLoc(), diag::err_template_arg_not_convertible)
6643 << Arg->getType() << ParamType;
6644 Diag(Param->getLocation(), diag::note_template_param_here);
6650 case NPV_NullPointer:
6651 Diag(Arg->getExprLoc(), diag::warn_cxx98_compat_template_arg_null);
6652 Converted = TemplateArgument(Context.getCanonicalType(ParamType),
6658 // -- For a non-type template-parameter of type pointer to data
6659 // member, qualification conversions (4.4) are applied.
6660 assert(ParamType->isMemberPointerType() && "Only pointers to members remain");
6662 if (CheckTemplateArgumentPointerToMember(*this, Param, ParamType, Arg,
6668 static void DiagnoseTemplateParameterListArityMismatch(
6669 Sema &S, TemplateParameterList *New, TemplateParameterList *Old,
6670 Sema::TemplateParameterListEqualKind Kind, SourceLocation TemplateArgLoc);
6672 /// Check a template argument against its corresponding
6673 /// template template parameter.
6675 /// This routine implements the semantics of C++ [temp.arg.template].
6676 /// It returns true if an error occurred, and false otherwise.
6677 bool Sema::CheckTemplateTemplateArgument(TemplateParameterList *Params,
6678 TemplateArgumentLoc &Arg) {
6679 TemplateName Name = Arg.getArgument().getAsTemplateOrTemplatePattern();
6680 TemplateDecl *Template = Name.getAsTemplateDecl();
6682 // Any dependent template name is fine.
6683 assert(Name.isDependent() && "Non-dependent template isn't a declaration?");
6687 if (Template->isInvalidDecl())
6690 // C++0x [temp.arg.template]p1:
6691 // A template-argument for a template template-parameter shall be
6692 // the name of a class template or an alias template, expressed as an
6693 // id-expression. When the template-argument names a class template, only
6694 // primary class templates are considered when matching the
6695 // template template argument with the corresponding parameter;
6696 // partial specializations are not considered even if their
6697 // parameter lists match that of the template template parameter.
6699 // Note that we also allow template template parameters here, which
6700 // will happen when we are dealing with, e.g., class template
6701 // partial specializations.
6702 if (!isa<ClassTemplateDecl>(Template) &&
6703 !isa<TemplateTemplateParmDecl>(Template) &&
6704 !isa<TypeAliasTemplateDecl>(Template) &&
6705 !isa<BuiltinTemplateDecl>(Template)) {
6706 assert(isa<FunctionTemplateDecl>(Template) &&
6707 "Only function templates are possible here");
6708 Diag(Arg.getLocation(), diag::err_template_arg_not_valid_template);
6709 Diag(Template->getLocation(), diag::note_template_arg_refers_here_func)
6713 // C++1z [temp.arg.template]p3: (DR 150)
6714 // A template-argument matches a template template-parameter P when P
6715 // is at least as specialized as the template-argument A.
6716 if (getLangOpts().RelaxedTemplateTemplateArgs) {
6717 // Quick check for the common case:
6718 // If P contains a parameter pack, then A [...] matches P if each of A's
6719 // template parameters matches the corresponding template parameter in
6720 // the template-parameter-list of P.
6721 if (TemplateParameterListsAreEqual(
6722 Template->getTemplateParameters(), Params, false,
6723 TPL_TemplateTemplateArgumentMatch, Arg.getLocation()))
6726 if (isTemplateTemplateParameterAtLeastAsSpecializedAs(Params, Template,
6729 // FIXME: Produce better diagnostics for deduction failures.
6732 return !TemplateParameterListsAreEqual(Template->getTemplateParameters(),
6735 TPL_TemplateTemplateArgumentMatch,
6739 /// Given a non-type template argument that refers to a
6740 /// declaration and the type of its corresponding non-type template
6741 /// parameter, produce an expression that properly refers to that
6744 Sema::BuildExpressionFromDeclTemplateArgument(const TemplateArgument &Arg,
6746 SourceLocation Loc) {
6747 // C++ [temp.param]p8:
6749 // A non-type template-parameter of type "array of T" or
6750 // "function returning T" is adjusted to be of type "pointer to
6751 // T" or "pointer to function returning T", respectively.
6752 if (ParamType->isArrayType())
6753 ParamType = Context.getArrayDecayedType(ParamType);
6754 else if (ParamType->isFunctionType())
6755 ParamType = Context.getPointerType(ParamType);
6757 // For a NULL non-type template argument, return nullptr casted to the
6758 // parameter's type.
6759 if (Arg.getKind() == TemplateArgument::NullPtr) {
6760 return ImpCastExprToType(
6761 new (Context) CXXNullPtrLiteralExpr(Context.NullPtrTy, Loc),
6763 ParamType->getAs<MemberPointerType>()
6764 ? CK_NullToMemberPointer
6765 : CK_NullToPointer);
6767 assert(Arg.getKind() == TemplateArgument::Declaration &&
6768 "Only declaration template arguments permitted here");
6770 ValueDecl *VD = Arg.getAsDecl();
6772 if (VD->getDeclContext()->isRecord() &&
6773 (isa<CXXMethodDecl>(VD) || isa<FieldDecl>(VD) ||
6774 isa<IndirectFieldDecl>(VD))) {
6775 // If the value is a class member, we might have a pointer-to-member.
6776 // Determine whether the non-type template template parameter is of
6777 // pointer-to-member type. If so, we need to build an appropriate
6778 // expression for a pointer-to-member, since a "normal" DeclRefExpr
6779 // would refer to the member itself.
6780 if (ParamType->isMemberPointerType()) {
6782 = Context.getTypeDeclType(cast<RecordDecl>(VD->getDeclContext()));
6783 NestedNameSpecifier *Qualifier
6784 = NestedNameSpecifier::Create(Context, nullptr, false,
6785 ClassType.getTypePtr());
6787 SS.MakeTrivial(Context, Qualifier, Loc);
6789 // The actual value-ness of this is unimportant, but for
6790 // internal consistency's sake, references to instance methods
6792 ExprValueKind VK = VK_LValue;
6793 if (isa<CXXMethodDecl>(VD) && cast<CXXMethodDecl>(VD)->isInstance())
6796 ExprResult RefExpr = BuildDeclRefExpr(VD,
6797 VD->getType().getNonReferenceType(),
6801 if (RefExpr.isInvalid())
6804 RefExpr = CreateBuiltinUnaryOp(Loc, UO_AddrOf, RefExpr.get());
6806 // We might need to perform a trailing qualification conversion, since
6807 // the element type on the parameter could be more qualified than the
6808 // element type in the expression we constructed.
6809 bool ObjCLifetimeConversion;
6810 if (IsQualificationConversion(((Expr*) RefExpr.get())->getType(),
6811 ParamType.getUnqualifiedType(), false,
6812 ObjCLifetimeConversion))
6813 RefExpr = ImpCastExprToType(RefExpr.get(), ParamType.getUnqualifiedType(), CK_NoOp);
6815 assert(!RefExpr.isInvalid() &&
6816 Context.hasSameType(((Expr*) RefExpr.get())->getType(),
6817 ParamType.getUnqualifiedType()));
6822 QualType T = VD->getType().getNonReferenceType();
6824 if (ParamType->isPointerType()) {
6825 // When the non-type template parameter is a pointer, take the
6826 // address of the declaration.
6827 ExprResult RefExpr = BuildDeclRefExpr(VD, T, VK_LValue, Loc);
6828 if (RefExpr.isInvalid())
6831 if (!Context.hasSameUnqualifiedType(ParamType->getPointeeType(), T) &&
6832 (T->isFunctionType() || T->isArrayType())) {
6833 // Decay functions and arrays unless we're forming a pointer to array.
6834 RefExpr = DefaultFunctionArrayConversion(RefExpr.get());
6835 if (RefExpr.isInvalid())
6841 // Take the address of everything else
6842 return CreateBuiltinUnaryOp(Loc, UO_AddrOf, RefExpr.get());
6845 ExprValueKind VK = VK_RValue;
6847 // If the non-type template parameter has reference type, qualify the
6848 // resulting declaration reference with the extra qualifiers on the
6849 // type that the reference refers to.
6850 if (const ReferenceType *TargetRef = ParamType->getAs<ReferenceType>()) {
6852 T = Context.getQualifiedType(T,
6853 TargetRef->getPointeeType().getQualifiers());
6854 } else if (isa<FunctionDecl>(VD)) {
6855 // References to functions are always lvalues.
6859 return BuildDeclRefExpr(VD, T, VK, Loc);
6862 /// Construct a new expression that refers to the given
6863 /// integral template argument with the given source-location
6866 /// This routine takes care of the mapping from an integral template
6867 /// argument (which may have any integral type) to the appropriate
6870 Sema::BuildExpressionFromIntegralTemplateArgument(const TemplateArgument &Arg,
6871 SourceLocation Loc) {
6872 assert(Arg.getKind() == TemplateArgument::Integral &&
6873 "Operation is only valid for integral template arguments");
6874 QualType OrigT = Arg.getIntegralType();
6876 // If this is an enum type that we're instantiating, we need to use an integer
6877 // type the same size as the enumerator. We don't want to build an
6878 // IntegerLiteral with enum type. The integer type of an enum type can be of
6879 // any integral type with C++11 enum classes, make sure we create the right
6880 // type of literal for it.
6882 if (const EnumType *ET = OrigT->getAs<EnumType>())
6883 T = ET->getDecl()->getIntegerType();
6886 if (T->isAnyCharacterType()) {
6887 CharacterLiteral::CharacterKind Kind;
6888 if (T->isWideCharType())
6889 Kind = CharacterLiteral::Wide;
6890 else if (T->isChar8Type() && getLangOpts().Char8)
6891 Kind = CharacterLiteral::UTF8;
6892 else if (T->isChar16Type())
6893 Kind = CharacterLiteral::UTF16;
6894 else if (T->isChar32Type())
6895 Kind = CharacterLiteral::UTF32;
6897 Kind = CharacterLiteral::Ascii;
6899 E = new (Context) CharacterLiteral(Arg.getAsIntegral().getZExtValue(),
6901 } else if (T->isBooleanType()) {
6902 E = new (Context) CXXBoolLiteralExpr(Arg.getAsIntegral().getBoolValue(),
6904 } else if (T->isNullPtrType()) {
6905 E = new (Context) CXXNullPtrLiteralExpr(Context.NullPtrTy, Loc);
6907 E = IntegerLiteral::Create(Context, Arg.getAsIntegral(), T, Loc);
6910 if (OrigT->isEnumeralType()) {
6911 // FIXME: This is a hack. We need a better way to handle substituted
6912 // non-type template parameters.
6913 E = CStyleCastExpr::Create(Context, OrigT, VK_RValue, CK_IntegralCast, E,
6915 Context.getTrivialTypeSourceInfo(OrigT, Loc),
6922 /// Match two template parameters within template parameter lists.
6923 static bool MatchTemplateParameterKind(Sema &S, NamedDecl *New, NamedDecl *Old,
6925 Sema::TemplateParameterListEqualKind Kind,
6926 SourceLocation TemplateArgLoc) {
6927 // Check the actual kind (type, non-type, template).
6928 if (Old->getKind() != New->getKind()) {
6930 unsigned NextDiag = diag::err_template_param_different_kind;
6931 if (TemplateArgLoc.isValid()) {
6932 S.Diag(TemplateArgLoc, diag::err_template_arg_template_params_mismatch);
6933 NextDiag = diag::note_template_param_different_kind;
6935 S.Diag(New->getLocation(), NextDiag)
6936 << (Kind != Sema::TPL_TemplateMatch);
6937 S.Diag(Old->getLocation(), diag::note_template_prev_declaration)
6938 << (Kind != Sema::TPL_TemplateMatch);
6944 // Check that both are parameter packs or neither are parameter packs.
6945 // However, if we are matching a template template argument to a
6946 // template template parameter, the template template parameter can have
6947 // a parameter pack where the template template argument does not.
6948 if (Old->isTemplateParameterPack() != New->isTemplateParameterPack() &&
6949 !(Kind == Sema::TPL_TemplateTemplateArgumentMatch &&
6950 Old->isTemplateParameterPack())) {
6952 unsigned NextDiag = diag::err_template_parameter_pack_non_pack;
6953 if (TemplateArgLoc.isValid()) {
6954 S.Diag(TemplateArgLoc,
6955 diag::err_template_arg_template_params_mismatch);
6956 NextDiag = diag::note_template_parameter_pack_non_pack;
6959 unsigned ParamKind = isa<TemplateTypeParmDecl>(New)? 0
6960 : isa<NonTypeTemplateParmDecl>(New)? 1
6962 S.Diag(New->getLocation(), NextDiag)
6963 << ParamKind << New->isParameterPack();
6964 S.Diag(Old->getLocation(), diag::note_template_parameter_pack_here)
6965 << ParamKind << Old->isParameterPack();
6971 // For non-type template parameters, check the type of the parameter.
6972 if (NonTypeTemplateParmDecl *OldNTTP
6973 = dyn_cast<NonTypeTemplateParmDecl>(Old)) {
6974 NonTypeTemplateParmDecl *NewNTTP = cast<NonTypeTemplateParmDecl>(New);
6976 // If we are matching a template template argument to a template
6977 // template parameter and one of the non-type template parameter types
6978 // is dependent, then we must wait until template instantiation time
6979 // to actually compare the arguments.
6980 if (Kind == Sema::TPL_TemplateTemplateArgumentMatch &&
6981 (OldNTTP->getType()->isDependentType() ||
6982 NewNTTP->getType()->isDependentType()))
6985 if (!S.Context.hasSameType(OldNTTP->getType(), NewNTTP->getType())) {
6987 unsigned NextDiag = diag::err_template_nontype_parm_different_type;
6988 if (TemplateArgLoc.isValid()) {
6989 S.Diag(TemplateArgLoc,
6990 diag::err_template_arg_template_params_mismatch);
6991 NextDiag = diag::note_template_nontype_parm_different_type;
6993 S.Diag(NewNTTP->getLocation(), NextDiag)
6994 << NewNTTP->getType()
6995 << (Kind != Sema::TPL_TemplateMatch);
6996 S.Diag(OldNTTP->getLocation(),
6997 diag::note_template_nontype_parm_prev_declaration)
6998 << OldNTTP->getType();
7007 // For template template parameters, check the template parameter types.
7008 // The template parameter lists of template template
7009 // parameters must agree.
7010 if (TemplateTemplateParmDecl *OldTTP
7011 = dyn_cast<TemplateTemplateParmDecl>(Old)) {
7012 TemplateTemplateParmDecl *NewTTP = cast<TemplateTemplateParmDecl>(New);
7013 return S.TemplateParameterListsAreEqual(NewTTP->getTemplateParameters(),
7014 OldTTP->getTemplateParameters(),
7016 (Kind == Sema::TPL_TemplateMatch
7017 ? Sema::TPL_TemplateTemplateParmMatch
7025 /// Diagnose a known arity mismatch when comparing template argument
7028 void DiagnoseTemplateParameterListArityMismatch(Sema &S,
7029 TemplateParameterList *New,
7030 TemplateParameterList *Old,
7031 Sema::TemplateParameterListEqualKind Kind,
7032 SourceLocation TemplateArgLoc) {
7033 unsigned NextDiag = diag::err_template_param_list_different_arity;
7034 if (TemplateArgLoc.isValid()) {
7035 S.Diag(TemplateArgLoc, diag::err_template_arg_template_params_mismatch);
7036 NextDiag = diag::note_template_param_list_different_arity;
7038 S.Diag(New->getTemplateLoc(), NextDiag)
7039 << (New->size() > Old->size())
7040 << (Kind != Sema::TPL_TemplateMatch)
7041 << SourceRange(New->getTemplateLoc(), New->getRAngleLoc());
7042 S.Diag(Old->getTemplateLoc(), diag::note_template_prev_declaration)
7043 << (Kind != Sema::TPL_TemplateMatch)
7044 << SourceRange(Old->getTemplateLoc(), Old->getRAngleLoc());
7047 /// Determine whether the given template parameter lists are
7050 /// \param New The new template parameter list, typically written in the
7051 /// source code as part of a new template declaration.
7053 /// \param Old The old template parameter list, typically found via
7054 /// name lookup of the template declared with this template parameter
7057 /// \param Complain If true, this routine will produce a diagnostic if
7058 /// the template parameter lists are not equivalent.
7060 /// \param Kind describes how we are to match the template parameter lists.
7062 /// \param TemplateArgLoc If this source location is valid, then we
7063 /// are actually checking the template parameter list of a template
7064 /// argument (New) against the template parameter list of its
7065 /// corresponding template template parameter (Old). We produce
7066 /// slightly different diagnostics in this scenario.
7068 /// \returns True if the template parameter lists are equal, false
7071 Sema::TemplateParameterListsAreEqual(TemplateParameterList *New,
7072 TemplateParameterList *Old,
7074 TemplateParameterListEqualKind Kind,
7075 SourceLocation TemplateArgLoc) {
7076 if (Old->size() != New->size() && Kind != TPL_TemplateTemplateArgumentMatch) {
7078 DiagnoseTemplateParameterListArityMismatch(*this, New, Old, Kind,
7084 // C++0x [temp.arg.template]p3:
7085 // A template-argument matches a template template-parameter (call it P)
7086 // when each of the template parameters in the template-parameter-list of
7087 // the template-argument's corresponding class template or alias template
7088 // (call it A) matches the corresponding template parameter in the
7089 // template-parameter-list of P. [...]
7090 TemplateParameterList::iterator NewParm = New->begin();
7091 TemplateParameterList::iterator NewParmEnd = New->end();
7092 for (TemplateParameterList::iterator OldParm = Old->begin(),
7093 OldParmEnd = Old->end();
7094 OldParm != OldParmEnd; ++OldParm) {
7095 if (Kind != TPL_TemplateTemplateArgumentMatch ||
7096 !(*OldParm)->isTemplateParameterPack()) {
7097 if (NewParm == NewParmEnd) {
7099 DiagnoseTemplateParameterListArityMismatch(*this, New, Old, Kind,
7105 if (!MatchTemplateParameterKind(*this, *NewParm, *OldParm, Complain,
7106 Kind, TemplateArgLoc))
7113 // C++0x [temp.arg.template]p3:
7114 // [...] When P's template- parameter-list contains a template parameter
7115 // pack (14.5.3), the template parameter pack will match zero or more
7116 // template parameters or template parameter packs in the
7117 // template-parameter-list of A with the same type and form as the
7118 // template parameter pack in P (ignoring whether those template
7119 // parameters are template parameter packs).
7120 for (; NewParm != NewParmEnd; ++NewParm) {
7121 if (!MatchTemplateParameterKind(*this, *NewParm, *OldParm, Complain,
7122 Kind, TemplateArgLoc))
7127 // Make sure we exhausted all of the arguments.
7128 if (NewParm != NewParmEnd) {
7130 DiagnoseTemplateParameterListArityMismatch(*this, New, Old, Kind,
7139 /// Check whether a template can be declared within this scope.
7141 /// If the template declaration is valid in this scope, returns
7142 /// false. Otherwise, issues a diagnostic and returns true.
7144 Sema::CheckTemplateDeclScope(Scope *S, TemplateParameterList *TemplateParams) {
7148 // Find the nearest enclosing declaration scope.
7149 while ((S->getFlags() & Scope::DeclScope) == 0 ||
7150 (S->getFlags() & Scope::TemplateParamScope) != 0)
7154 // A template [...] shall not have C linkage.
7155 DeclContext *Ctx = S->getEntity();
7156 if (Ctx && Ctx->isExternCContext()) {
7157 Diag(TemplateParams->getTemplateLoc(), diag::err_template_linkage)
7158 << TemplateParams->getSourceRange();
7159 if (const LinkageSpecDecl *LSD = Ctx->getExternCContext())
7160 Diag(LSD->getExternLoc(), diag::note_extern_c_begins_here);
7163 Ctx = Ctx->getRedeclContext();
7166 // A template-declaration can appear only as a namespace scope or
7167 // class scope declaration.
7169 if (Ctx->isFileContext())
7171 if (CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(Ctx)) {
7172 // C++ [temp.mem]p2:
7173 // A local class shall not have member templates.
7174 if (RD->isLocalClass())
7175 return Diag(TemplateParams->getTemplateLoc(),
7176 diag::err_template_inside_local_class)
7177 << TemplateParams->getSourceRange();
7183 return Diag(TemplateParams->getTemplateLoc(),
7184 diag::err_template_outside_namespace_or_class_scope)
7185 << TemplateParams->getSourceRange();
7188 /// Determine what kind of template specialization the given declaration
7190 static TemplateSpecializationKind getTemplateSpecializationKind(Decl *D) {
7192 return TSK_Undeclared;
7194 if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(D))
7195 return Record->getTemplateSpecializationKind();
7196 if (FunctionDecl *Function = dyn_cast<FunctionDecl>(D))
7197 return Function->getTemplateSpecializationKind();
7198 if (VarDecl *Var = dyn_cast<VarDecl>(D))
7199 return Var->getTemplateSpecializationKind();
7201 return TSK_Undeclared;
7204 /// Check whether a specialization is well-formed in the current
7207 /// This routine determines whether a template specialization can be declared
7208 /// in the current context (C++ [temp.expl.spec]p2).
7210 /// \param S the semantic analysis object for which this check is being
7213 /// \param Specialized the entity being specialized or instantiated, which
7214 /// may be a kind of template (class template, function template, etc.) or
7215 /// a member of a class template (member function, static data member,
7218 /// \param PrevDecl the previous declaration of this entity, if any.
7220 /// \param Loc the location of the explicit specialization or instantiation of
7223 /// \param IsPartialSpecialization whether this is a partial specialization of
7224 /// a class template.
7226 /// \returns true if there was an error that we cannot recover from, false
7228 static bool CheckTemplateSpecializationScope(Sema &S,
7229 NamedDecl *Specialized,
7230 NamedDecl *PrevDecl,
7232 bool IsPartialSpecialization) {
7233 // Keep these "kind" numbers in sync with the %select statements in the
7234 // various diagnostics emitted by this routine.
7236 if (isa<ClassTemplateDecl>(Specialized))
7237 EntityKind = IsPartialSpecialization? 1 : 0;
7238 else if (isa<VarTemplateDecl>(Specialized))
7239 EntityKind = IsPartialSpecialization ? 3 : 2;
7240 else if (isa<FunctionTemplateDecl>(Specialized))
7242 else if (isa<CXXMethodDecl>(Specialized))
7244 else if (isa<VarDecl>(Specialized))
7246 else if (isa<RecordDecl>(Specialized))
7248 else if (isa<EnumDecl>(Specialized) && S.getLangOpts().CPlusPlus11)
7251 S.Diag(Loc, diag::err_template_spec_unknown_kind)
7252 << S.getLangOpts().CPlusPlus11;
7253 S.Diag(Specialized->getLocation(), diag::note_specialized_entity);
7257 // C++ [temp.expl.spec]p2:
7258 // An explicit specialization may be declared in any scope in which
7259 // the corresponding primary template may be defined.
7260 if (S.CurContext->getRedeclContext()->isFunctionOrMethod()) {
7261 S.Diag(Loc, diag::err_template_spec_decl_function_scope)
7266 // C++ [temp.class.spec]p6:
7267 // A class template partial specialization may be declared in any
7268 // scope in which the primary template may be defined.
7269 DeclContext *SpecializedContext =
7270 Specialized->getDeclContext()->getRedeclContext();
7271 DeclContext *DC = S.CurContext->getRedeclContext();
7273 // Make sure that this redeclaration (or definition) occurs in the same
7274 // scope or an enclosing namespace.
7275 if (!(DC->isFileContext() ? DC->Encloses(SpecializedContext)
7276 : DC->Equals(SpecializedContext))) {
7277 if (isa<TranslationUnitDecl>(SpecializedContext))
7278 S.Diag(Loc, diag::err_template_spec_redecl_global_scope)
7279 << EntityKind << Specialized;
7281 auto *ND = cast<NamedDecl>(SpecializedContext);
7282 int Diag = diag::err_template_spec_redecl_out_of_scope;
7283 if (S.getLangOpts().MicrosoftExt && !DC->isRecord())
7284 Diag = diag::ext_ms_template_spec_redecl_out_of_scope;
7285 S.Diag(Loc, Diag) << EntityKind << Specialized
7286 << ND << isa<CXXRecordDecl>(ND);
7289 S.Diag(Specialized->getLocation(), diag::note_specialized_entity);
7291 // Don't allow specializing in the wrong class during error recovery.
7292 // Otherwise, things can go horribly wrong.
7300 static SourceRange findTemplateParameterInType(unsigned Depth, Expr *E) {
7301 if (!E->isTypeDependent())
7302 return SourceLocation();
7303 DependencyChecker Checker(Depth, /*IgnoreNonTypeDependent*/true);
7304 Checker.TraverseStmt(E);
7305 if (Checker.MatchLoc.isInvalid())
7306 return E->getSourceRange();
7307 return Checker.MatchLoc;
7310 static SourceRange findTemplateParameter(unsigned Depth, TypeLoc TL) {
7311 if (!TL.getType()->isDependentType())
7312 return SourceLocation();
7313 DependencyChecker Checker(Depth, /*IgnoreNonTypeDependent*/true);
7314 Checker.TraverseTypeLoc(TL);
7315 if (Checker.MatchLoc.isInvalid())
7316 return TL.getSourceRange();
7317 return Checker.MatchLoc;
7320 /// Subroutine of Sema::CheckTemplatePartialSpecializationArgs
7321 /// that checks non-type template partial specialization arguments.
7322 static bool CheckNonTypeTemplatePartialSpecializationArgs(
7323 Sema &S, SourceLocation TemplateNameLoc, NonTypeTemplateParmDecl *Param,
7324 const TemplateArgument *Args, unsigned NumArgs, bool IsDefaultArgument) {
7325 for (unsigned I = 0; I != NumArgs; ++I) {
7326 if (Args[I].getKind() == TemplateArgument::Pack) {
7327 if (CheckNonTypeTemplatePartialSpecializationArgs(
7328 S, TemplateNameLoc, Param, Args[I].pack_begin(),
7329 Args[I].pack_size(), IsDefaultArgument))
7335 if (Args[I].getKind() != TemplateArgument::Expression)
7338 Expr *ArgExpr = Args[I].getAsExpr();
7340 // We can have a pack expansion of any of the bullets below.
7341 if (PackExpansionExpr *Expansion = dyn_cast<PackExpansionExpr>(ArgExpr))
7342 ArgExpr = Expansion->getPattern();
7344 // Strip off any implicit casts we added as part of type checking.
7345 while (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(ArgExpr))
7346 ArgExpr = ICE->getSubExpr();
7348 // C++ [temp.class.spec]p8:
7349 // A non-type argument is non-specialized if it is the name of a
7350 // non-type parameter. All other non-type arguments are
7353 // Below, we check the two conditions that only apply to
7354 // specialized non-type arguments, so skip any non-specialized
7356 if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(ArgExpr))
7357 if (isa<NonTypeTemplateParmDecl>(DRE->getDecl()))
7360 // C++ [temp.class.spec]p9:
7361 // Within the argument list of a class template partial
7362 // specialization, the following restrictions apply:
7363 // -- A partially specialized non-type argument expression
7364 // shall not involve a template parameter of the partial
7365 // specialization except when the argument expression is a
7366 // simple identifier.
7367 // -- The type of a template parameter corresponding to a
7368 // specialized non-type argument shall not be dependent on a
7369 // parameter of the specialization.
7370 // DR1315 removes the first bullet, leaving an incoherent set of rules.
7371 // We implement a compromise between the original rules and DR1315:
7372 // -- A specialized non-type template argument shall not be
7373 // type-dependent and the corresponding template parameter
7374 // shall have a non-dependent type.
7375 SourceRange ParamUseRange =
7376 findTemplateParameterInType(Param->getDepth(), ArgExpr);
7377 if (ParamUseRange.isValid()) {
7378 if (IsDefaultArgument) {
7379 S.Diag(TemplateNameLoc,
7380 diag::err_dependent_non_type_arg_in_partial_spec);
7381 S.Diag(ParamUseRange.getBegin(),
7382 diag::note_dependent_non_type_default_arg_in_partial_spec)
7385 S.Diag(ParamUseRange.getBegin(),
7386 diag::err_dependent_non_type_arg_in_partial_spec)
7392 ParamUseRange = findTemplateParameter(
7393 Param->getDepth(), Param->getTypeSourceInfo()->getTypeLoc());
7394 if (ParamUseRange.isValid()) {
7395 S.Diag(IsDefaultArgument ? TemplateNameLoc : ArgExpr->getBeginLoc(),
7396 diag::err_dependent_typed_non_type_arg_in_partial_spec)
7397 << Param->getType();
7398 S.Diag(Param->getLocation(), diag::note_template_param_here)
7399 << (IsDefaultArgument ? ParamUseRange : SourceRange())
7408 /// Check the non-type template arguments of a class template
7409 /// partial specialization according to C++ [temp.class.spec]p9.
7411 /// \param TemplateNameLoc the location of the template name.
7412 /// \param PrimaryTemplate the template parameters of the primary class
7414 /// \param NumExplicit the number of explicitly-specified template arguments.
7415 /// \param TemplateArgs the template arguments of the class template
7416 /// partial specialization.
7418 /// \returns \c true if there was an error, \c false otherwise.
7419 bool Sema::CheckTemplatePartialSpecializationArgs(
7420 SourceLocation TemplateNameLoc, TemplateDecl *PrimaryTemplate,
7421 unsigned NumExplicit, ArrayRef<TemplateArgument> TemplateArgs) {
7422 // We have to be conservative when checking a template in a dependent
7424 if (PrimaryTemplate->getDeclContext()->isDependentContext())
7427 TemplateParameterList *TemplateParams =
7428 PrimaryTemplate->getTemplateParameters();
7429 for (unsigned I = 0, N = TemplateParams->size(); I != N; ++I) {
7430 NonTypeTemplateParmDecl *Param
7431 = dyn_cast<NonTypeTemplateParmDecl>(TemplateParams->getParam(I));
7435 if (CheckNonTypeTemplatePartialSpecializationArgs(*this, TemplateNameLoc,
7436 Param, &TemplateArgs[I],
7437 1, I >= NumExplicit))
7444 DeclResult Sema::ActOnClassTemplateSpecialization(
7445 Scope *S, unsigned TagSpec, TagUseKind TUK, SourceLocation KWLoc,
7446 SourceLocation ModulePrivateLoc, TemplateIdAnnotation &TemplateId,
7447 const ParsedAttributesView &Attr,
7448 MultiTemplateParamsArg TemplateParameterLists, SkipBodyInfo *SkipBody) {
7449 assert(TUK != TUK_Reference && "References are not specializations");
7451 CXXScopeSpec &SS = TemplateId.SS;
7453 // NOTE: KWLoc is the location of the tag keyword. This will instead
7454 // store the location of the outermost template keyword in the declaration.
7455 SourceLocation TemplateKWLoc = TemplateParameterLists.size() > 0
7456 ? TemplateParameterLists[0]->getTemplateLoc() : KWLoc;
7457 SourceLocation TemplateNameLoc = TemplateId.TemplateNameLoc;
7458 SourceLocation LAngleLoc = TemplateId.LAngleLoc;
7459 SourceLocation RAngleLoc = TemplateId.RAngleLoc;
7461 // Find the class template we're specializing
7462 TemplateName Name = TemplateId.Template.get();
7463 ClassTemplateDecl *ClassTemplate
7464 = dyn_cast_or_null<ClassTemplateDecl>(Name.getAsTemplateDecl());
7466 if (!ClassTemplate) {
7467 Diag(TemplateNameLoc, diag::err_not_class_template_specialization)
7468 << (Name.getAsTemplateDecl() &&
7469 isa<TemplateTemplateParmDecl>(Name.getAsTemplateDecl()));
7473 bool isMemberSpecialization = false;
7474 bool isPartialSpecialization = false;
7476 // Check the validity of the template headers that introduce this
7478 // FIXME: We probably shouldn't complain about these headers for
7479 // friend declarations.
7480 bool Invalid = false;
7481 TemplateParameterList *TemplateParams =
7482 MatchTemplateParametersToScopeSpecifier(
7483 KWLoc, TemplateNameLoc, SS, &TemplateId,
7484 TemplateParameterLists, TUK == TUK_Friend, isMemberSpecialization,
7489 if (TemplateParams && TemplateParams->size() > 0) {
7490 isPartialSpecialization = true;
7492 if (TUK == TUK_Friend) {
7493 Diag(KWLoc, diag::err_partial_specialization_friend)
7494 << SourceRange(LAngleLoc, RAngleLoc);
7498 // C++ [temp.class.spec]p10:
7499 // The template parameter list of a specialization shall not
7500 // contain default template argument values.
7501 for (unsigned I = 0, N = TemplateParams->size(); I != N; ++I) {
7502 Decl *Param = TemplateParams->getParam(I);
7503 if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(Param)) {
7504 if (TTP->hasDefaultArgument()) {
7505 Diag(TTP->getDefaultArgumentLoc(),
7506 diag::err_default_arg_in_partial_spec);
7507 TTP->removeDefaultArgument();
7509 } else if (NonTypeTemplateParmDecl *NTTP
7510 = dyn_cast<NonTypeTemplateParmDecl>(Param)) {
7511 if (Expr *DefArg = NTTP->getDefaultArgument()) {
7512 Diag(NTTP->getDefaultArgumentLoc(),
7513 diag::err_default_arg_in_partial_spec)
7514 << DefArg->getSourceRange();
7515 NTTP->removeDefaultArgument();
7518 TemplateTemplateParmDecl *TTP = cast<TemplateTemplateParmDecl>(Param);
7519 if (TTP->hasDefaultArgument()) {
7520 Diag(TTP->getDefaultArgument().getLocation(),
7521 diag::err_default_arg_in_partial_spec)
7522 << TTP->getDefaultArgument().getSourceRange();
7523 TTP->removeDefaultArgument();
7527 } else if (TemplateParams) {
7528 if (TUK == TUK_Friend)
7529 Diag(KWLoc, diag::err_template_spec_friend)
7530 << FixItHint::CreateRemoval(
7531 SourceRange(TemplateParams->getTemplateLoc(),
7532 TemplateParams->getRAngleLoc()))
7533 << SourceRange(LAngleLoc, RAngleLoc);
7535 assert(TUK == TUK_Friend && "should have a 'template<>' for this decl");
7538 // Check that the specialization uses the same tag kind as the
7539 // original template.
7540 TagTypeKind Kind = TypeWithKeyword::getTagTypeKindForTypeSpec(TagSpec);
7541 assert(Kind != TTK_Enum && "Invalid enum tag in class template spec!");
7542 if (!isAcceptableTagRedeclaration(ClassTemplate->getTemplatedDecl(),
7543 Kind, TUK == TUK_Definition, KWLoc,
7544 ClassTemplate->getIdentifier())) {
7545 Diag(KWLoc, diag::err_use_with_wrong_tag)
7547 << FixItHint::CreateReplacement(KWLoc,
7548 ClassTemplate->getTemplatedDecl()->getKindName());
7549 Diag(ClassTemplate->getTemplatedDecl()->getLocation(),
7550 diag::note_previous_use);
7551 Kind = ClassTemplate->getTemplatedDecl()->getTagKind();
7554 // Translate the parser's template argument list in our AST format.
7555 TemplateArgumentListInfo TemplateArgs =
7556 makeTemplateArgumentListInfo(*this, TemplateId);
7558 // Check for unexpanded parameter packs in any of the template arguments.
7559 for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I)
7560 if (DiagnoseUnexpandedParameterPack(TemplateArgs[I],
7561 UPPC_PartialSpecialization))
7564 // Check that the template argument list is well-formed for this
7566 SmallVector<TemplateArgument, 4> Converted;
7567 if (CheckTemplateArgumentList(ClassTemplate, TemplateNameLoc,
7568 TemplateArgs, false, Converted))
7571 // Find the class template (partial) specialization declaration that
7572 // corresponds to these arguments.
7573 if (isPartialSpecialization) {
7574 if (CheckTemplatePartialSpecializationArgs(TemplateNameLoc, ClassTemplate,
7575 TemplateArgs.size(), Converted))
7578 // FIXME: Move this to CheckTemplatePartialSpecializationArgs so we
7579 // also do it during instantiation.
7580 bool InstantiationDependent;
7581 if (!Name.isDependent() &&
7582 !TemplateSpecializationType::anyDependentTemplateArguments(
7583 TemplateArgs.arguments(), InstantiationDependent)) {
7584 Diag(TemplateNameLoc, diag::err_partial_spec_fully_specialized)
7585 << ClassTemplate->getDeclName();
7586 isPartialSpecialization = false;
7590 void *InsertPos = nullptr;
7591 ClassTemplateSpecializationDecl *PrevDecl = nullptr;
7593 if (isPartialSpecialization)
7594 // FIXME: Template parameter list matters, too
7595 PrevDecl = ClassTemplate->findPartialSpecialization(Converted, InsertPos);
7597 PrevDecl = ClassTemplate->findSpecialization(Converted, InsertPos);
7599 ClassTemplateSpecializationDecl *Specialization = nullptr;
7601 // Check whether we can declare a class template specialization in
7602 // the current scope.
7603 if (TUK != TUK_Friend &&
7604 CheckTemplateSpecializationScope(*this, ClassTemplate, PrevDecl,
7606 isPartialSpecialization))
7609 // The canonical type
7611 if (isPartialSpecialization) {
7612 // Build the canonical type that describes the converted template
7613 // arguments of the class template partial specialization.
7614 TemplateName CanonTemplate = Context.getCanonicalTemplateName(Name);
7615 CanonType = Context.getTemplateSpecializationType(CanonTemplate,
7618 if (Context.hasSameType(CanonType,
7619 ClassTemplate->getInjectedClassNameSpecialization())) {
7620 // C++ [temp.class.spec]p9b3:
7622 // -- The argument list of the specialization shall not be identical
7623 // to the implicit argument list of the primary template.
7625 // This rule has since been removed, because it's redundant given DR1495,
7626 // but we keep it because it produces better diagnostics and recovery.
7627 Diag(TemplateNameLoc, diag::err_partial_spec_args_match_primary_template)
7628 << /*class template*/0 << (TUK == TUK_Definition)
7629 << FixItHint::CreateRemoval(SourceRange(LAngleLoc, RAngleLoc));
7630 return CheckClassTemplate(S, TagSpec, TUK, KWLoc, SS,
7631 ClassTemplate->getIdentifier(),
7635 AS_none, /*ModulePrivateLoc=*/SourceLocation(),
7636 /*FriendLoc*/SourceLocation(),
7637 TemplateParameterLists.size() - 1,
7638 TemplateParameterLists.data());
7641 // Create a new class template partial specialization declaration node.
7642 ClassTemplatePartialSpecializationDecl *PrevPartial
7643 = cast_or_null<ClassTemplatePartialSpecializationDecl>(PrevDecl);
7644 ClassTemplatePartialSpecializationDecl *Partial
7645 = ClassTemplatePartialSpecializationDecl::Create(Context, Kind,
7646 ClassTemplate->getDeclContext(),
7647 KWLoc, TemplateNameLoc,
7654 SetNestedNameSpecifier(*this, Partial, SS);
7655 if (TemplateParameterLists.size() > 1 && SS.isSet()) {
7656 Partial->setTemplateParameterListsInfo(
7657 Context, TemplateParameterLists.drop_back(1));
7661 ClassTemplate->AddPartialSpecialization(Partial, InsertPos);
7662 Specialization = Partial;
7664 // If we are providing an explicit specialization of a member class
7665 // template specialization, make a note of that.
7666 if (PrevPartial && PrevPartial->getInstantiatedFromMember())
7667 PrevPartial->setMemberSpecialization();
7669 CheckTemplatePartialSpecialization(Partial);
7671 // Create a new class template specialization declaration node for
7672 // this explicit specialization or friend declaration.
7674 = ClassTemplateSpecializationDecl::Create(Context, Kind,
7675 ClassTemplate->getDeclContext(),
7676 KWLoc, TemplateNameLoc,
7680 SetNestedNameSpecifier(*this, Specialization, SS);
7681 if (TemplateParameterLists.size() > 0) {
7682 Specialization->setTemplateParameterListsInfo(Context,
7683 TemplateParameterLists);
7687 ClassTemplate->AddSpecialization(Specialization, InsertPos);
7689 if (CurContext->isDependentContext()) {
7690 TemplateName CanonTemplate = Context.getCanonicalTemplateName(Name);
7691 CanonType = Context.getTemplateSpecializationType(
7692 CanonTemplate, Converted);
7694 CanonType = Context.getTypeDeclType(Specialization);
7698 // C++ [temp.expl.spec]p6:
7699 // If a template, a member template or the member of a class template is
7700 // explicitly specialized then that specialization shall be declared
7701 // before the first use of that specialization that would cause an implicit
7702 // instantiation to take place, in every translation unit in which such a
7703 // use occurs; no diagnostic is required.
7704 if (PrevDecl && PrevDecl->getPointOfInstantiation().isValid()) {
7706 for (Decl *Prev = PrevDecl; Prev; Prev = Prev->getPreviousDecl()) {
7707 // Is there any previous explicit specialization declaration?
7708 if (getTemplateSpecializationKind(Prev) == TSK_ExplicitSpecialization) {
7715 SourceRange Range(TemplateNameLoc, RAngleLoc);
7716 Diag(TemplateNameLoc, diag::err_specialization_after_instantiation)
7717 << Context.getTypeDeclType(Specialization) << Range;
7719 Diag(PrevDecl->getPointOfInstantiation(),
7720 diag::note_instantiation_required_here)
7721 << (PrevDecl->getTemplateSpecializationKind()
7722 != TSK_ImplicitInstantiation);
7727 // If this is not a friend, note that this is an explicit specialization.
7728 if (TUK != TUK_Friend)
7729 Specialization->setSpecializationKind(TSK_ExplicitSpecialization);
7731 // Check that this isn't a redefinition of this specialization.
7732 if (TUK == TUK_Definition) {
7733 RecordDecl *Def = Specialization->getDefinition();
7734 NamedDecl *Hidden = nullptr;
7735 if (Def && SkipBody && !hasVisibleDefinition(Def, &Hidden)) {
7736 SkipBody->ShouldSkip = true;
7737 SkipBody->Previous = Def;
7738 makeMergedDefinitionVisible(Hidden);
7740 SourceRange Range(TemplateNameLoc, RAngleLoc);
7741 Diag(TemplateNameLoc, diag::err_redefinition) << Specialization << Range;
7742 Diag(Def->getLocation(), diag::note_previous_definition);
7743 Specialization->setInvalidDecl();
7748 ProcessDeclAttributeList(S, Specialization, Attr);
7750 // Add alignment attributes if necessary; these attributes are checked when
7751 // the ASTContext lays out the structure.
7752 if (TUK == TUK_Definition && (!SkipBody || !SkipBody->ShouldSkip)) {
7753 AddAlignmentAttributesForRecord(Specialization);
7754 AddMsStructLayoutForRecord(Specialization);
7757 if (ModulePrivateLoc.isValid())
7758 Diag(Specialization->getLocation(), diag::err_module_private_specialization)
7759 << (isPartialSpecialization? 1 : 0)
7760 << FixItHint::CreateRemoval(ModulePrivateLoc);
7762 // Build the fully-sugared type for this class template
7763 // specialization as the user wrote in the specialization
7764 // itself. This means that we'll pretty-print the type retrieved
7765 // from the specialization's declaration the way that the user
7766 // actually wrote the specialization, rather than formatting the
7767 // name based on the "canonical" representation used to store the
7768 // template arguments in the specialization.
7769 TypeSourceInfo *WrittenTy
7770 = Context.getTemplateSpecializationTypeInfo(Name, TemplateNameLoc,
7771 TemplateArgs, CanonType);
7772 if (TUK != TUK_Friend) {
7773 Specialization->setTypeAsWritten(WrittenTy);
7774 Specialization->setTemplateKeywordLoc(TemplateKWLoc);
7777 // C++ [temp.expl.spec]p9:
7778 // A template explicit specialization is in the scope of the
7779 // namespace in which the template was defined.
7781 // We actually implement this paragraph where we set the semantic
7782 // context (in the creation of the ClassTemplateSpecializationDecl),
7783 // but we also maintain the lexical context where the actual
7784 // definition occurs.
7785 Specialization->setLexicalDeclContext(CurContext);
7787 // We may be starting the definition of this specialization.
7788 if (TUK == TUK_Definition && (!SkipBody || !SkipBody->ShouldSkip))
7789 Specialization->startDefinition();
7791 if (TUK == TUK_Friend) {
7792 FriendDecl *Friend = FriendDecl::Create(Context, CurContext,
7796 Friend->setAccess(AS_public);
7797 CurContext->addDecl(Friend);
7799 // Add the specialization into its lexical context, so that it can
7800 // be seen when iterating through the list of declarations in that
7801 // context. However, specializations are not found by name lookup.
7802 CurContext->addDecl(Specialization);
7805 if (SkipBody && SkipBody->ShouldSkip)
7806 return SkipBody->Previous;
7808 return Specialization;
7811 Decl *Sema::ActOnTemplateDeclarator(Scope *S,
7812 MultiTemplateParamsArg TemplateParameterLists,
7814 Decl *NewDecl = HandleDeclarator(S, D, TemplateParameterLists);
7815 ActOnDocumentableDecl(NewDecl);
7819 /// Strips various properties off an implicit instantiation
7820 /// that has just been explicitly specialized.
7821 static void StripImplicitInstantiation(NamedDecl *D) {
7822 D->dropAttr<DLLImportAttr>();
7823 D->dropAttr<DLLExportAttr>();
7825 if (FunctionDecl *FD = dyn_cast<FunctionDecl>(D))
7826 FD->setInlineSpecified(false);
7829 /// Compute the diagnostic location for an explicit instantiation
7830 // declaration or definition.
7831 static SourceLocation DiagLocForExplicitInstantiation(
7832 NamedDecl* D, SourceLocation PointOfInstantiation) {
7833 // Explicit instantiations following a specialization have no effect and
7834 // hence no PointOfInstantiation. In that case, walk decl backwards
7835 // until a valid name loc is found.
7836 SourceLocation PrevDiagLoc = PointOfInstantiation;
7837 for (Decl *Prev = D; Prev && !PrevDiagLoc.isValid();
7838 Prev = Prev->getPreviousDecl()) {
7839 PrevDiagLoc = Prev->getLocation();
7841 assert(PrevDiagLoc.isValid() &&
7842 "Explicit instantiation without point of instantiation?");
7846 /// Diagnose cases where we have an explicit template specialization
7847 /// before/after an explicit template instantiation, producing diagnostics
7848 /// for those cases where they are required and determining whether the
7849 /// new specialization/instantiation will have any effect.
7851 /// \param NewLoc the location of the new explicit specialization or
7854 /// \param NewTSK the kind of the new explicit specialization or instantiation.
7856 /// \param PrevDecl the previous declaration of the entity.
7858 /// \param PrevTSK the kind of the old explicit specialization or instantiatin.
7860 /// \param PrevPointOfInstantiation if valid, indicates where the previus
7861 /// declaration was instantiated (either implicitly or explicitly).
7863 /// \param HasNoEffect will be set to true to indicate that the new
7864 /// specialization or instantiation has no effect and should be ignored.
7866 /// \returns true if there was an error that should prevent the introduction of
7867 /// the new declaration into the AST, false otherwise.
7869 Sema::CheckSpecializationInstantiationRedecl(SourceLocation NewLoc,
7870 TemplateSpecializationKind NewTSK,
7871 NamedDecl *PrevDecl,
7872 TemplateSpecializationKind PrevTSK,
7873 SourceLocation PrevPointOfInstantiation,
7874 bool &HasNoEffect) {
7875 HasNoEffect = false;
7878 case TSK_Undeclared:
7879 case TSK_ImplicitInstantiation:
7881 (PrevTSK == TSK_Undeclared || PrevTSK == TSK_ImplicitInstantiation) &&
7882 "previous declaration must be implicit!");
7885 case TSK_ExplicitSpecialization:
7887 case TSK_Undeclared:
7888 case TSK_ExplicitSpecialization:
7889 // Okay, we're just specializing something that is either already
7890 // explicitly specialized or has merely been mentioned without any
7894 case TSK_ImplicitInstantiation:
7895 if (PrevPointOfInstantiation.isInvalid()) {
7896 // The declaration itself has not actually been instantiated, so it is
7897 // still okay to specialize it.
7898 StripImplicitInstantiation(PrevDecl);
7904 case TSK_ExplicitInstantiationDeclaration:
7905 case TSK_ExplicitInstantiationDefinition:
7906 assert((PrevTSK == TSK_ImplicitInstantiation ||
7907 PrevPointOfInstantiation.isValid()) &&
7908 "Explicit instantiation without point of instantiation?");
7910 // C++ [temp.expl.spec]p6:
7911 // If a template, a member template or the member of a class template
7912 // is explicitly specialized then that specialization shall be declared
7913 // before the first use of that specialization that would cause an
7914 // implicit instantiation to take place, in every translation unit in
7915 // which such a use occurs; no diagnostic is required.
7916 for (Decl *Prev = PrevDecl; Prev; Prev = Prev->getPreviousDecl()) {
7917 // Is there any previous explicit specialization declaration?
7918 if (getTemplateSpecializationKind(Prev) == TSK_ExplicitSpecialization)
7922 Diag(NewLoc, diag::err_specialization_after_instantiation)
7924 Diag(PrevPointOfInstantiation, diag::note_instantiation_required_here)
7925 << (PrevTSK != TSK_ImplicitInstantiation);
7929 llvm_unreachable("The switch over PrevTSK must be exhaustive.");
7931 case TSK_ExplicitInstantiationDeclaration:
7933 case TSK_ExplicitInstantiationDeclaration:
7934 // This explicit instantiation declaration is redundant (that's okay).
7938 case TSK_Undeclared:
7939 case TSK_ImplicitInstantiation:
7940 // We're explicitly instantiating something that may have already been
7941 // implicitly instantiated; that's fine.
7944 case TSK_ExplicitSpecialization:
7945 // C++0x [temp.explicit]p4:
7946 // For a given set of template parameters, if an explicit instantiation
7947 // of a template appears after a declaration of an explicit
7948 // specialization for that template, the explicit instantiation has no
7953 case TSK_ExplicitInstantiationDefinition:
7954 // C++0x [temp.explicit]p10:
7955 // If an entity is the subject of both an explicit instantiation
7956 // declaration and an explicit instantiation definition in the same
7957 // translation unit, the definition shall follow the declaration.
7959 diag::err_explicit_instantiation_declaration_after_definition);
7961 // Explicit instantiations following a specialization have no effect and
7962 // hence no PrevPointOfInstantiation. In that case, walk decl backwards
7963 // until a valid name loc is found.
7964 Diag(DiagLocForExplicitInstantiation(PrevDecl, PrevPointOfInstantiation),
7965 diag::note_explicit_instantiation_definition_here);
7969 llvm_unreachable("Unexpected TemplateSpecializationKind!");
7971 case TSK_ExplicitInstantiationDefinition:
7973 case TSK_Undeclared:
7974 case TSK_ImplicitInstantiation:
7975 // We're explicitly instantiating something that may have already been
7976 // implicitly instantiated; that's fine.
7979 case TSK_ExplicitSpecialization:
7980 // C++ DR 259, C++0x [temp.explicit]p4:
7981 // For a given set of template parameters, if an explicit
7982 // instantiation of a template appears after a declaration of
7983 // an explicit specialization for that template, the explicit
7984 // instantiation has no effect.
7985 Diag(NewLoc, diag::warn_explicit_instantiation_after_specialization)
7987 Diag(PrevDecl->getLocation(),
7988 diag::note_previous_template_specialization);
7992 case TSK_ExplicitInstantiationDeclaration:
7993 // We're explicitly instantiating a definition for something for which we
7994 // were previously asked to suppress instantiations. That's fine.
7996 // C++0x [temp.explicit]p4:
7997 // For a given set of template parameters, if an explicit instantiation
7998 // of a template appears after a declaration of an explicit
7999 // specialization for that template, the explicit instantiation has no
8001 for (Decl *Prev = PrevDecl; Prev; Prev = Prev->getPreviousDecl()) {
8002 // Is there any previous explicit specialization declaration?
8003 if (getTemplateSpecializationKind(Prev) == TSK_ExplicitSpecialization) {
8011 case TSK_ExplicitInstantiationDefinition:
8012 // C++0x [temp.spec]p5:
8013 // For a given template and a given set of template-arguments,
8014 // - an explicit instantiation definition shall appear at most once
8017 // MSVCCompat: MSVC silently ignores duplicate explicit instantiations.
8018 Diag(NewLoc, (getLangOpts().MSVCCompat)
8019 ? diag::ext_explicit_instantiation_duplicate
8020 : diag::err_explicit_instantiation_duplicate)
8022 Diag(DiagLocForExplicitInstantiation(PrevDecl, PrevPointOfInstantiation),
8023 diag::note_previous_explicit_instantiation);
8029 llvm_unreachable("Missing specialization/instantiation case?");
8032 /// Perform semantic analysis for the given dependent function
8033 /// template specialization.
8035 /// The only possible way to get a dependent function template specialization
8036 /// is with a friend declaration, like so:
8039 /// template \<class T> void foo(T);
8040 /// template \<class T> class A {
8041 /// friend void foo<>(T);
8045 /// There really isn't any useful analysis we can do here, so we
8046 /// just store the information.
8048 Sema::CheckDependentFunctionTemplateSpecialization(FunctionDecl *FD,
8049 const TemplateArgumentListInfo &ExplicitTemplateArgs,
8050 LookupResult &Previous) {
8051 // Remove anything from Previous that isn't a function template in
8052 // the correct context.
8053 DeclContext *FDLookupContext = FD->getDeclContext()->getRedeclContext();
8054 LookupResult::Filter F = Previous.makeFilter();
8055 enum DiscardReason { NotAFunctionTemplate, NotAMemberOfEnclosing };
8056 SmallVector<std::pair<DiscardReason, Decl *>, 8> DiscardedCandidates;
8057 while (F.hasNext()) {
8058 NamedDecl *D = F.next()->getUnderlyingDecl();
8059 if (!isa<FunctionTemplateDecl>(D)) {
8061 DiscardedCandidates.push_back(std::make_pair(NotAFunctionTemplate, D));
8065 if (!FDLookupContext->InEnclosingNamespaceSetOf(
8066 D->getDeclContext()->getRedeclContext())) {
8068 DiscardedCandidates.push_back(std::make_pair(NotAMemberOfEnclosing, D));
8074 if (Previous.empty()) {
8075 Diag(FD->getLocation(),
8076 diag::err_dependent_function_template_spec_no_match);
8077 for (auto &P : DiscardedCandidates)
8078 Diag(P.second->getLocation(),
8079 diag::note_dependent_function_template_spec_discard_reason)
8084 FD->setDependentTemplateSpecialization(Context, Previous.asUnresolvedSet(),
8085 ExplicitTemplateArgs);
8089 /// Perform semantic analysis for the given function template
8092 /// This routine performs all of the semantic analysis required for an
8093 /// explicit function template specialization. On successful completion,
8094 /// the function declaration \p FD will become a function template
8097 /// \param FD the function declaration, which will be updated to become a
8098 /// function template specialization.
8100 /// \param ExplicitTemplateArgs the explicitly-provided template arguments,
8101 /// if any. Note that this may be valid info even when 0 arguments are
8102 /// explicitly provided as in, e.g., \c void sort<>(char*, char*);
8103 /// as it anyway contains info on the angle brackets locations.
8105 /// \param Previous the set of declarations that may be specialized by
8106 /// this function specialization.
8108 /// \param QualifiedFriend whether this is a lookup for a qualified friend
8109 /// declaration with no explicit template argument list that might be
8110 /// befriending a function template specialization.
8111 bool Sema::CheckFunctionTemplateSpecialization(
8112 FunctionDecl *FD, TemplateArgumentListInfo *ExplicitTemplateArgs,
8113 LookupResult &Previous, bool QualifiedFriend) {
8114 // The set of function template specializations that could match this
8115 // explicit function template specialization.
8116 UnresolvedSet<8> Candidates;
8117 TemplateSpecCandidateSet FailedCandidates(FD->getLocation(),
8118 /*ForTakingAddress=*/false);
8120 llvm::SmallDenseMap<FunctionDecl *, TemplateArgumentListInfo, 8>
8121 ConvertedTemplateArgs;
8123 DeclContext *FDLookupContext = FD->getDeclContext()->getRedeclContext();
8124 for (LookupResult::iterator I = Previous.begin(), E = Previous.end();
8126 NamedDecl *Ovl = (*I)->getUnderlyingDecl();
8127 if (FunctionTemplateDecl *FunTmpl = dyn_cast<FunctionTemplateDecl>(Ovl)) {
8128 // Only consider templates found within the same semantic lookup scope as
8130 if (!FDLookupContext->InEnclosingNamespaceSetOf(
8131 Ovl->getDeclContext()->getRedeclContext()))
8134 // When matching a constexpr member function template specialization
8135 // against the primary template, we don't yet know whether the
8136 // specialization has an implicit 'const' (because we don't know whether
8137 // it will be a static member function until we know which template it
8138 // specializes), so adjust it now assuming it specializes this template.
8139 QualType FT = FD->getType();
8140 if (FD->isConstexpr()) {
8141 CXXMethodDecl *OldMD =
8142 dyn_cast<CXXMethodDecl>(FunTmpl->getTemplatedDecl());
8143 if (OldMD && OldMD->isConst()) {
8144 const FunctionProtoType *FPT = FT->castAs<FunctionProtoType>();
8145 FunctionProtoType::ExtProtoInfo EPI = FPT->getExtProtoInfo();
8146 EPI.TypeQuals.addConst();
8147 FT = Context.getFunctionType(FPT->getReturnType(),
8148 FPT->getParamTypes(), EPI);
8152 TemplateArgumentListInfo Args;
8153 if (ExplicitTemplateArgs)
8154 Args = *ExplicitTemplateArgs;
8156 // C++ [temp.expl.spec]p11:
8157 // A trailing template-argument can be left unspecified in the
8158 // template-id naming an explicit function template specialization
8159 // provided it can be deduced from the function argument type.
8160 // Perform template argument deduction to determine whether we may be
8161 // specializing this template.
8162 // FIXME: It is somewhat wasteful to build
8163 TemplateDeductionInfo Info(FailedCandidates.getLocation());
8164 FunctionDecl *Specialization = nullptr;
8165 if (TemplateDeductionResult TDK = DeduceTemplateArguments(
8166 cast<FunctionTemplateDecl>(FunTmpl->getFirstDecl()),
8167 ExplicitTemplateArgs ? &Args : nullptr, FT, Specialization,
8169 // Template argument deduction failed; record why it failed, so
8170 // that we can provide nifty diagnostics.
8171 FailedCandidates.addCandidate().set(
8172 I.getPair(), FunTmpl->getTemplatedDecl(),
8173 MakeDeductionFailureInfo(Context, TDK, Info));
8178 // Target attributes are part of the cuda function signature, so
8179 // the deduced template's cuda target must match that of the
8180 // specialization. Given that C++ template deduction does not
8181 // take target attributes into account, we reject candidates
8182 // here that have a different target.
8183 if (LangOpts.CUDA &&
8184 IdentifyCUDATarget(Specialization,
8185 /* IgnoreImplicitHDAttributes = */ true) !=
8186 IdentifyCUDATarget(FD, /* IgnoreImplicitHDAttributes = */ true)) {
8187 FailedCandidates.addCandidate().set(
8188 I.getPair(), FunTmpl->getTemplatedDecl(),
8189 MakeDeductionFailureInfo(Context, TDK_CUDATargetMismatch, Info));
8193 // Record this candidate.
8194 if (ExplicitTemplateArgs)
8195 ConvertedTemplateArgs[Specialization] = std::move(Args);
8196 Candidates.addDecl(Specialization, I.getAccess());
8200 // For a qualified friend declaration (with no explicit marker to indicate
8201 // that a template specialization was intended), note all (template and
8202 // non-template) candidates.
8203 if (QualifiedFriend && Candidates.empty()) {
8204 Diag(FD->getLocation(), diag::err_qualified_friend_no_match)
8205 << FD->getDeclName() << FDLookupContext;
8206 // FIXME: We should form a single candidate list and diagnose all
8207 // candidates at once, to get proper sorting and limiting.
8208 for (auto *OldND : Previous) {
8209 if (auto *OldFD = dyn_cast<FunctionDecl>(OldND->getUnderlyingDecl()))
8210 NoteOverloadCandidate(OldND, OldFD, FD->getType(), false);
8212 FailedCandidates.NoteCandidates(*this, FD->getLocation());
8216 // Find the most specialized function template.
8217 UnresolvedSetIterator Result = getMostSpecialized(
8218 Candidates.begin(), Candidates.end(), FailedCandidates, FD->getLocation(),
8219 PDiag(diag::err_function_template_spec_no_match) << FD->getDeclName(),
8220 PDiag(diag::err_function_template_spec_ambiguous)
8221 << FD->getDeclName() << (ExplicitTemplateArgs != nullptr),
8222 PDiag(diag::note_function_template_spec_matched));
8224 if (Result == Candidates.end())
8227 // Ignore access information; it doesn't figure into redeclaration checking.
8228 FunctionDecl *Specialization = cast<FunctionDecl>(*Result);
8230 FunctionTemplateSpecializationInfo *SpecInfo
8231 = Specialization->getTemplateSpecializationInfo();
8232 assert(SpecInfo && "Function template specialization info missing?");
8234 // Note: do not overwrite location info if previous template
8235 // specialization kind was explicit.
8236 TemplateSpecializationKind TSK = SpecInfo->getTemplateSpecializationKind();
8237 if (TSK == TSK_Undeclared || TSK == TSK_ImplicitInstantiation) {
8238 Specialization->setLocation(FD->getLocation());
8239 Specialization->setLexicalDeclContext(FD->getLexicalDeclContext());
8240 // C++11 [dcl.constexpr]p1: An explicit specialization of a constexpr
8241 // function can differ from the template declaration with respect to
8242 // the constexpr specifier.
8243 // FIXME: We need an update record for this AST mutation.
8244 // FIXME: What if there are multiple such prior declarations (for instance,
8245 // from different modules)?
8246 Specialization->setConstexpr(FD->isConstexpr());
8249 // FIXME: Check if the prior specialization has a point of instantiation.
8250 // If so, we have run afoul of .
8252 // If this is a friend declaration, then we're not really declaring
8253 // an explicit specialization.
8254 bool isFriend = (FD->getFriendObjectKind() != Decl::FOK_None);
8256 // Check the scope of this explicit specialization.
8258 CheckTemplateSpecializationScope(*this,
8259 Specialization->getPrimaryTemplate(),
8260 Specialization, FD->getLocation(),
8264 // C++ [temp.expl.spec]p6:
8265 // If a template, a member template or the member of a class template is
8266 // explicitly specialized then that specialization shall be declared
8267 // before the first use of that specialization that would cause an implicit
8268 // instantiation to take place, in every translation unit in which such a
8269 // use occurs; no diagnostic is required.
8270 bool HasNoEffect = false;
8272 CheckSpecializationInstantiationRedecl(FD->getLocation(),
8273 TSK_ExplicitSpecialization,
8275 SpecInfo->getTemplateSpecializationKind(),
8276 SpecInfo->getPointOfInstantiation(),
8280 // Mark the prior declaration as an explicit specialization, so that later
8281 // clients know that this is an explicit specialization.
8283 // Since explicit specializations do not inherit '=delete' from their
8284 // primary function template - check if the 'specialization' that was
8285 // implicitly generated (during template argument deduction for partial
8286 // ordering) from the most specialized of all the function templates that
8287 // 'FD' could have been specializing, has a 'deleted' definition. If so,
8288 // first check that it was implicitly generated during template argument
8289 // deduction by making sure it wasn't referenced, and then reset the deleted
8290 // flag to not-deleted, so that we can inherit that information from 'FD'.
8291 if (Specialization->isDeleted() && !SpecInfo->isExplicitSpecialization() &&
8292 !Specialization->getCanonicalDecl()->isReferenced()) {
8293 // FIXME: This assert will not hold in the presence of modules.
8295 Specialization->getCanonicalDecl() == Specialization &&
8296 "This must be the only existing declaration of this specialization");
8297 // FIXME: We need an update record for this AST mutation.
8298 Specialization->setDeletedAsWritten(false);
8300 // FIXME: We need an update record for this AST mutation.
8301 SpecInfo->setTemplateSpecializationKind(TSK_ExplicitSpecialization);
8302 MarkUnusedFileScopedDecl(Specialization);
8305 // Turn the given function declaration into a function template
8306 // specialization, with the template arguments from the previous
8308 // Take copies of (semantic and syntactic) template argument lists.
8309 const TemplateArgumentList* TemplArgs = new (Context)
8310 TemplateArgumentList(Specialization->getTemplateSpecializationArgs());
8311 FD->setFunctionTemplateSpecialization(
8312 Specialization->getPrimaryTemplate(), TemplArgs, /*InsertPos=*/nullptr,
8313 SpecInfo->getTemplateSpecializationKind(),
8314 ExplicitTemplateArgs ? &ConvertedTemplateArgs[Specialization] : nullptr);
8316 // A function template specialization inherits the target attributes
8317 // of its template. (We require the attributes explicitly in the
8318 // code to match, but a template may have implicit attributes by
8319 // virtue e.g. of being constexpr, and it passes these implicit
8320 // attributes on to its specializations.)
8322 inheritCUDATargetAttrs(FD, *Specialization->getPrimaryTemplate());
8324 // The "previous declaration" for this function template specialization is
8325 // the prior function template specialization.
8327 Previous.addDecl(Specialization);
8331 /// Perform semantic analysis for the given non-template member
8334 /// This routine performs all of the semantic analysis required for an
8335 /// explicit member function specialization. On successful completion,
8336 /// the function declaration \p FD will become a member function
8339 /// \param Member the member declaration, which will be updated to become a
8342 /// \param Previous the set of declarations, one of which may be specialized
8343 /// by this function specialization; the set will be modified to contain the
8344 /// redeclared member.
8346 Sema::CheckMemberSpecialization(NamedDecl *Member, LookupResult &Previous) {
8347 assert(!isa<TemplateDecl>(Member) && "Only for non-template members");
8349 // Try to find the member we are instantiating.
8350 NamedDecl *FoundInstantiation = nullptr;
8351 NamedDecl *Instantiation = nullptr;
8352 NamedDecl *InstantiatedFrom = nullptr;
8353 MemberSpecializationInfo *MSInfo = nullptr;
8355 if (Previous.empty()) {
8356 // Nowhere to look anyway.
8357 } else if (FunctionDecl *Function = dyn_cast<FunctionDecl>(Member)) {
8358 for (LookupResult::iterator I = Previous.begin(), E = Previous.end();
8360 NamedDecl *D = (*I)->getUnderlyingDecl();
8361 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(D)) {
8362 QualType Adjusted = Function->getType();
8363 if (!hasExplicitCallingConv(Adjusted))
8364 Adjusted = adjustCCAndNoReturn(Adjusted, Method->getType());
8365 // This doesn't handle deduced return types, but both function
8366 // declarations should be undeduced at this point.
8367 if (Context.hasSameType(Adjusted, Method->getType())) {
8368 FoundInstantiation = *I;
8369 Instantiation = Method;
8370 InstantiatedFrom = Method->getInstantiatedFromMemberFunction();
8371 MSInfo = Method->getMemberSpecializationInfo();
8376 } else if (isa<VarDecl>(Member)) {
8378 if (Previous.isSingleResult() &&
8379 (PrevVar = dyn_cast<VarDecl>(Previous.getFoundDecl())))
8380 if (PrevVar->isStaticDataMember()) {
8381 FoundInstantiation = Previous.getRepresentativeDecl();
8382 Instantiation = PrevVar;
8383 InstantiatedFrom = PrevVar->getInstantiatedFromStaticDataMember();
8384 MSInfo = PrevVar->getMemberSpecializationInfo();
8386 } else if (isa<RecordDecl>(Member)) {
8387 CXXRecordDecl *PrevRecord;
8388 if (Previous.isSingleResult() &&
8389 (PrevRecord = dyn_cast<CXXRecordDecl>(Previous.getFoundDecl()))) {
8390 FoundInstantiation = Previous.getRepresentativeDecl();
8391 Instantiation = PrevRecord;
8392 InstantiatedFrom = PrevRecord->getInstantiatedFromMemberClass();
8393 MSInfo = PrevRecord->getMemberSpecializationInfo();
8395 } else if (isa<EnumDecl>(Member)) {
8397 if (Previous.isSingleResult() &&
8398 (PrevEnum = dyn_cast<EnumDecl>(Previous.getFoundDecl()))) {
8399 FoundInstantiation = Previous.getRepresentativeDecl();
8400 Instantiation = PrevEnum;
8401 InstantiatedFrom = PrevEnum->getInstantiatedFromMemberEnum();
8402 MSInfo = PrevEnum->getMemberSpecializationInfo();
8406 if (!Instantiation) {
8407 // There is no previous declaration that matches. Since member
8408 // specializations are always out-of-line, the caller will complain about
8409 // this mismatch later.
8413 // A member specialization in a friend declaration isn't really declaring
8414 // an explicit specialization, just identifying a specific (possibly implicit)
8415 // specialization. Don't change the template specialization kind.
8417 // FIXME: Is this really valid? Other compilers reject.
8418 if (Member->getFriendObjectKind() != Decl::FOK_None) {
8419 // Preserve instantiation information.
8420 if (InstantiatedFrom && isa<CXXMethodDecl>(Member)) {
8421 cast<CXXMethodDecl>(Member)->setInstantiationOfMemberFunction(
8422 cast<CXXMethodDecl>(InstantiatedFrom),
8423 cast<CXXMethodDecl>(Instantiation)->getTemplateSpecializationKind());
8424 } else if (InstantiatedFrom && isa<CXXRecordDecl>(Member)) {
8425 cast<CXXRecordDecl>(Member)->setInstantiationOfMemberClass(
8426 cast<CXXRecordDecl>(InstantiatedFrom),
8427 cast<CXXRecordDecl>(Instantiation)->getTemplateSpecializationKind());
8431 Previous.addDecl(FoundInstantiation);
8435 // Make sure that this is a specialization of a member.
8436 if (!InstantiatedFrom) {
8437 Diag(Member->getLocation(), diag::err_spec_member_not_instantiated)
8439 Diag(Instantiation->getLocation(), diag::note_specialized_decl);
8443 // C++ [temp.expl.spec]p6:
8444 // If a template, a member template or the member of a class template is
8445 // explicitly specialized then that specialization shall be declared
8446 // before the first use of that specialization that would cause an implicit
8447 // instantiation to take place, in every translation unit in which such a
8448 // use occurs; no diagnostic is required.
8449 assert(MSInfo && "Member specialization info missing?");
8451 bool HasNoEffect = false;
8452 if (CheckSpecializationInstantiationRedecl(Member->getLocation(),
8453 TSK_ExplicitSpecialization,
8455 MSInfo->getTemplateSpecializationKind(),
8456 MSInfo->getPointOfInstantiation(),
8460 // Check the scope of this explicit specialization.
8461 if (CheckTemplateSpecializationScope(*this,
8463 Instantiation, Member->getLocation(),
8467 // Note that this member specialization is an "instantiation of" the
8468 // corresponding member of the original template.
8469 if (auto *MemberFunction = dyn_cast<FunctionDecl>(Member)) {
8470 FunctionDecl *InstantiationFunction = cast<FunctionDecl>(Instantiation);
8471 if (InstantiationFunction->getTemplateSpecializationKind() ==
8472 TSK_ImplicitInstantiation) {
8473 // Explicit specializations of member functions of class templates do not
8474 // inherit '=delete' from the member function they are specializing.
8475 if (InstantiationFunction->isDeleted()) {
8476 // FIXME: This assert will not hold in the presence of modules.
8477 assert(InstantiationFunction->getCanonicalDecl() ==
8478 InstantiationFunction);
8479 // FIXME: We need an update record for this AST mutation.
8480 InstantiationFunction->setDeletedAsWritten(false);
8484 MemberFunction->setInstantiationOfMemberFunction(
8485 cast<CXXMethodDecl>(InstantiatedFrom), TSK_ExplicitSpecialization);
8486 } else if (auto *MemberVar = dyn_cast<VarDecl>(Member)) {
8487 MemberVar->setInstantiationOfStaticDataMember(
8488 cast<VarDecl>(InstantiatedFrom), TSK_ExplicitSpecialization);
8489 } else if (auto *MemberClass = dyn_cast<CXXRecordDecl>(Member)) {
8490 MemberClass->setInstantiationOfMemberClass(
8491 cast<CXXRecordDecl>(InstantiatedFrom), TSK_ExplicitSpecialization);
8492 } else if (auto *MemberEnum = dyn_cast<EnumDecl>(Member)) {
8493 MemberEnum->setInstantiationOfMemberEnum(
8494 cast<EnumDecl>(InstantiatedFrom), TSK_ExplicitSpecialization);
8496 llvm_unreachable("unknown member specialization kind");
8499 // Save the caller the trouble of having to figure out which declaration
8500 // this specialization matches.
8502 Previous.addDecl(FoundInstantiation);
8506 /// Complete the explicit specialization of a member of a class template by
8507 /// updating the instantiated member to be marked as an explicit specialization.
8509 /// \param OrigD The member declaration instantiated from the template.
8510 /// \param Loc The location of the explicit specialization of the member.
8511 template<typename DeclT>
8512 static void completeMemberSpecializationImpl(Sema &S, DeclT *OrigD,
8513 SourceLocation Loc) {
8514 if (OrigD->getTemplateSpecializationKind() != TSK_ImplicitInstantiation)
8517 // FIXME: Inform AST mutation listeners of this AST mutation.
8518 // FIXME: If there are multiple in-class declarations of the member (from
8519 // multiple modules, or a declaration and later definition of a member type),
8520 // should we update all of them?
8521 OrigD->setTemplateSpecializationKind(TSK_ExplicitSpecialization);
8522 OrigD->setLocation(Loc);
8525 void Sema::CompleteMemberSpecialization(NamedDecl *Member,
8526 LookupResult &Previous) {
8527 NamedDecl *Instantiation = cast<NamedDecl>(Member->getCanonicalDecl());
8528 if (Instantiation == Member)
8531 if (auto *Function = dyn_cast<CXXMethodDecl>(Instantiation))
8532 completeMemberSpecializationImpl(*this, Function, Member->getLocation());
8533 else if (auto *Var = dyn_cast<VarDecl>(Instantiation))
8534 completeMemberSpecializationImpl(*this, Var, Member->getLocation());
8535 else if (auto *Record = dyn_cast<CXXRecordDecl>(Instantiation))
8536 completeMemberSpecializationImpl(*this, Record, Member->getLocation());
8537 else if (auto *Enum = dyn_cast<EnumDecl>(Instantiation))
8538 completeMemberSpecializationImpl(*this, Enum, Member->getLocation());
8540 llvm_unreachable("unknown member specialization kind");
8543 /// Check the scope of an explicit instantiation.
8545 /// \returns true if a serious error occurs, false otherwise.
8546 static bool CheckExplicitInstantiationScope(Sema &S, NamedDecl *D,
8547 SourceLocation InstLoc,
8548 bool WasQualifiedName) {
8549 DeclContext *OrigContext= D->getDeclContext()->getEnclosingNamespaceContext();
8550 DeclContext *CurContext = S.CurContext->getRedeclContext();
8552 if (CurContext->isRecord()) {
8553 S.Diag(InstLoc, diag::err_explicit_instantiation_in_class)
8558 // C++11 [temp.explicit]p3:
8559 // An explicit instantiation shall appear in an enclosing namespace of its
8560 // template. If the name declared in the explicit instantiation is an
8561 // unqualified name, the explicit instantiation shall appear in the
8562 // namespace where its template is declared or, if that namespace is inline
8563 // (7.3.1), any namespace from its enclosing namespace set.
8565 // This is DR275, which we do not retroactively apply to C++98/03.
8566 if (WasQualifiedName) {
8567 if (CurContext->Encloses(OrigContext))
8570 if (CurContext->InEnclosingNamespaceSetOf(OrigContext))
8574 if (NamespaceDecl *NS = dyn_cast<NamespaceDecl>(OrigContext)) {
8575 if (WasQualifiedName)
8577 S.getLangOpts().CPlusPlus11?
8578 diag::err_explicit_instantiation_out_of_scope :
8579 diag::warn_explicit_instantiation_out_of_scope_0x)
8583 S.getLangOpts().CPlusPlus11?
8584 diag::err_explicit_instantiation_unqualified_wrong_namespace :
8585 diag::warn_explicit_instantiation_unqualified_wrong_namespace_0x)
8589 S.getLangOpts().CPlusPlus11?
8590 diag::err_explicit_instantiation_must_be_global :
8591 diag::warn_explicit_instantiation_must_be_global_0x)
8593 S.Diag(D->getLocation(), diag::note_explicit_instantiation_here);
8597 /// Determine whether the given scope specifier has a template-id in it.
8598 static bool ScopeSpecifierHasTemplateId(const CXXScopeSpec &SS) {
8602 // C++11 [temp.explicit]p3:
8603 // If the explicit instantiation is for a member function, a member class
8604 // or a static data member of a class template specialization, the name of
8605 // the class template specialization in the qualified-id for the member
8606 // name shall be a simple-template-id.
8608 // C++98 has the same restriction, just worded differently.
8609 for (NestedNameSpecifier *NNS = SS.getScopeRep(); NNS;
8610 NNS = NNS->getPrefix())
8611 if (const Type *T = NNS->getAsType())
8612 if (isa<TemplateSpecializationType>(T))
8618 /// Make a dllexport or dllimport attr on a class template specialization take
8620 static void dllExportImportClassTemplateSpecialization(
8621 Sema &S, ClassTemplateSpecializationDecl *Def) {
8622 auto *A = cast_or_null<InheritableAttr>(getDLLAttr(Def));
8623 assert(A && "dllExportImportClassTemplateSpecialization called "
8624 "on Def without dllexport or dllimport");
8626 // We reject explicit instantiations in class scope, so there should
8627 // never be any delayed exported classes to worry about.
8628 assert(S.DelayedDllExportClasses.empty() &&
8629 "delayed exports present at explicit instantiation");
8630 S.checkClassLevelDLLAttribute(Def);
8632 // Propagate attribute to base class templates.
8633 for (auto &B : Def->bases()) {
8634 if (auto *BT = dyn_cast_or_null<ClassTemplateSpecializationDecl>(
8635 B.getType()->getAsCXXRecordDecl()))
8636 S.propagateDLLAttrToBaseClassTemplate(Def, A, BT, B.getBeginLoc());
8639 S.referenceDLLExportedClassMethods();
8642 // Explicit instantiation of a class template specialization
8643 DeclResult Sema::ActOnExplicitInstantiation(
8644 Scope *S, SourceLocation ExternLoc, SourceLocation TemplateLoc,
8645 unsigned TagSpec, SourceLocation KWLoc, const CXXScopeSpec &SS,
8646 TemplateTy TemplateD, SourceLocation TemplateNameLoc,
8647 SourceLocation LAngleLoc, ASTTemplateArgsPtr TemplateArgsIn,
8648 SourceLocation RAngleLoc, const ParsedAttributesView &Attr) {
8649 // Find the class template we're specializing
8650 TemplateName Name = TemplateD.get();
8651 TemplateDecl *TD = Name.getAsTemplateDecl();
8652 // Check that the specialization uses the same tag kind as the
8653 // original template.
8654 TagTypeKind Kind = TypeWithKeyword::getTagTypeKindForTypeSpec(TagSpec);
8655 assert(Kind != TTK_Enum &&
8656 "Invalid enum tag in class template explicit instantiation!");
8658 ClassTemplateDecl *ClassTemplate = dyn_cast<ClassTemplateDecl>(TD);
8660 if (!ClassTemplate) {
8661 NonTagKind NTK = getNonTagTypeDeclKind(TD, Kind);
8662 Diag(TemplateNameLoc, diag::err_tag_reference_non_tag) << TD << NTK << Kind;
8663 Diag(TD->getLocation(), diag::note_previous_use);
8667 if (!isAcceptableTagRedeclaration(ClassTemplate->getTemplatedDecl(),
8668 Kind, /*isDefinition*/false, KWLoc,
8669 ClassTemplate->getIdentifier())) {
8670 Diag(KWLoc, diag::err_use_with_wrong_tag)
8672 << FixItHint::CreateReplacement(KWLoc,
8673 ClassTemplate->getTemplatedDecl()->getKindName());
8674 Diag(ClassTemplate->getTemplatedDecl()->getLocation(),
8675 diag::note_previous_use);
8676 Kind = ClassTemplate->getTemplatedDecl()->getTagKind();
8679 // C++0x [temp.explicit]p2:
8680 // There are two forms of explicit instantiation: an explicit instantiation
8681 // definition and an explicit instantiation declaration. An explicit
8682 // instantiation declaration begins with the extern keyword. [...]
8683 TemplateSpecializationKind TSK = ExternLoc.isInvalid()
8684 ? TSK_ExplicitInstantiationDefinition
8685 : TSK_ExplicitInstantiationDeclaration;
8687 if (TSK == TSK_ExplicitInstantiationDeclaration) {
8688 // Check for dllexport class template instantiation declarations.
8689 for (const ParsedAttr &AL : Attr) {
8690 if (AL.getKind() == ParsedAttr::AT_DLLExport) {
8692 diag::warn_attribute_dllexport_explicit_instantiation_decl);
8693 Diag(AL.getLoc(), diag::note_attribute);
8698 if (auto *A = ClassTemplate->getTemplatedDecl()->getAttr<DLLExportAttr>()) {
8700 diag::warn_attribute_dllexport_explicit_instantiation_decl);
8701 Diag(A->getLocation(), diag::note_attribute);
8705 // In MSVC mode, dllimported explicit instantiation definitions are treated as
8706 // instantiation declarations for most purposes.
8707 bool DLLImportExplicitInstantiationDef = false;
8708 if (TSK == TSK_ExplicitInstantiationDefinition &&
8709 Context.getTargetInfo().getCXXABI().isMicrosoft()) {
8710 // Check for dllimport class template instantiation definitions.
8712 ClassTemplate->getTemplatedDecl()->getAttr<DLLImportAttr>();
8713 for (const ParsedAttr &AL : Attr) {
8714 if (AL.getKind() == ParsedAttr::AT_DLLImport)
8716 if (AL.getKind() == ParsedAttr::AT_DLLExport) {
8717 // dllexport trumps dllimport here.
8723 TSK = TSK_ExplicitInstantiationDeclaration;
8724 DLLImportExplicitInstantiationDef = true;
8728 // Translate the parser's template argument list in our AST format.
8729 TemplateArgumentListInfo TemplateArgs(LAngleLoc, RAngleLoc);
8730 translateTemplateArguments(TemplateArgsIn, TemplateArgs);
8732 // Check that the template argument list is well-formed for this
8734 SmallVector<TemplateArgument, 4> Converted;
8735 if (CheckTemplateArgumentList(ClassTemplate, TemplateNameLoc,
8736 TemplateArgs, false, Converted))
8739 // Find the class template specialization declaration that
8740 // corresponds to these arguments.
8741 void *InsertPos = nullptr;
8742 ClassTemplateSpecializationDecl *PrevDecl
8743 = ClassTemplate->findSpecialization(Converted, InsertPos);
8745 TemplateSpecializationKind PrevDecl_TSK
8746 = PrevDecl ? PrevDecl->getTemplateSpecializationKind() : TSK_Undeclared;
8748 // C++0x [temp.explicit]p2:
8749 // [...] An explicit instantiation shall appear in an enclosing
8750 // namespace of its template. [...]
8752 // This is C++ DR 275.
8753 if (CheckExplicitInstantiationScope(*this, ClassTemplate, TemplateNameLoc,
8757 ClassTemplateSpecializationDecl *Specialization = nullptr;
8759 bool HasNoEffect = false;
8761 if (CheckSpecializationInstantiationRedecl(TemplateNameLoc, TSK,
8762 PrevDecl, PrevDecl_TSK,
8763 PrevDecl->getPointOfInstantiation(),
8767 // Even though HasNoEffect == true means that this explicit instantiation
8768 // has no effect on semantics, we go on to put its syntax in the AST.
8770 if (PrevDecl_TSK == TSK_ImplicitInstantiation ||
8771 PrevDecl_TSK == TSK_Undeclared) {
8772 // Since the only prior class template specialization with these
8773 // arguments was referenced but not declared, reuse that
8774 // declaration node as our own, updating the source location
8775 // for the template name to reflect our new declaration.
8776 // (Other source locations will be updated later.)
8777 Specialization = PrevDecl;
8778 Specialization->setLocation(TemplateNameLoc);
8782 if (PrevDecl_TSK == TSK_ExplicitInstantiationDeclaration &&
8783 DLLImportExplicitInstantiationDef) {
8784 // The new specialization might add a dllimport attribute.
8785 HasNoEffect = false;
8789 if (!Specialization) {
8790 // Create a new class template specialization declaration node for
8791 // this explicit specialization.
8793 = ClassTemplateSpecializationDecl::Create(Context, Kind,
8794 ClassTemplate->getDeclContext(),
8795 KWLoc, TemplateNameLoc,
8799 SetNestedNameSpecifier(*this, Specialization, SS);
8801 if (!HasNoEffect && !PrevDecl) {
8802 // Insert the new specialization.
8803 ClassTemplate->AddSpecialization(Specialization, InsertPos);
8807 // Build the fully-sugared type for this explicit instantiation as
8808 // the user wrote in the explicit instantiation itself. This means
8809 // that we'll pretty-print the type retrieved from the
8810 // specialization's declaration the way that the user actually wrote
8811 // the explicit instantiation, rather than formatting the name based
8812 // on the "canonical" representation used to store the template
8813 // arguments in the specialization.
8814 TypeSourceInfo *WrittenTy
8815 = Context.getTemplateSpecializationTypeInfo(Name, TemplateNameLoc,
8817 Context.getTypeDeclType(Specialization));
8818 Specialization->setTypeAsWritten(WrittenTy);
8820 // Set source locations for keywords.
8821 Specialization->setExternLoc(ExternLoc);
8822 Specialization->setTemplateKeywordLoc(TemplateLoc);
8823 Specialization->setBraceRange(SourceRange());
8825 bool PreviouslyDLLExported = Specialization->hasAttr<DLLExportAttr>();
8826 ProcessDeclAttributeList(S, Specialization, Attr);
8828 // Add the explicit instantiation into its lexical context. However,
8829 // since explicit instantiations are never found by name lookup, we
8830 // just put it into the declaration context directly.
8831 Specialization->setLexicalDeclContext(CurContext);
8832 CurContext->addDecl(Specialization);
8834 // Syntax is now OK, so return if it has no other effect on semantics.
8836 // Set the template specialization kind.
8837 Specialization->setTemplateSpecializationKind(TSK);
8838 return Specialization;
8841 // C++ [temp.explicit]p3:
8842 // A definition of a class template or class member template
8843 // shall be in scope at the point of the explicit instantiation of
8844 // the class template or class member template.
8846 // This check comes when we actually try to perform the
8848 ClassTemplateSpecializationDecl *Def
8849 = cast_or_null<ClassTemplateSpecializationDecl>(
8850 Specialization->getDefinition());
8852 InstantiateClassTemplateSpecialization(TemplateNameLoc, Specialization, TSK);
8853 else if (TSK == TSK_ExplicitInstantiationDefinition) {
8854 MarkVTableUsed(TemplateNameLoc, Specialization, true);
8855 Specialization->setPointOfInstantiation(Def->getPointOfInstantiation());
8858 // Instantiate the members of this class template specialization.
8859 Def = cast_or_null<ClassTemplateSpecializationDecl>(
8860 Specialization->getDefinition());
8862 TemplateSpecializationKind Old_TSK = Def->getTemplateSpecializationKind();
8863 // Fix a TSK_ExplicitInstantiationDeclaration followed by a
8864 // TSK_ExplicitInstantiationDefinition
8865 if (Old_TSK == TSK_ExplicitInstantiationDeclaration &&
8866 (TSK == TSK_ExplicitInstantiationDefinition ||
8867 DLLImportExplicitInstantiationDef)) {
8868 // FIXME: Need to notify the ASTMutationListener that we did this.
8869 Def->setTemplateSpecializationKind(TSK);
8871 if (!getDLLAttr(Def) && getDLLAttr(Specialization) &&
8872 (Context.getTargetInfo().getCXXABI().isMicrosoft() ||
8873 Context.getTargetInfo().getTriple().isWindowsItaniumEnvironment())) {
8874 // In the MS ABI, an explicit instantiation definition can add a dll
8875 // attribute to a template with a previous instantiation declaration.
8876 // MinGW doesn't allow this.
8877 auto *A = cast<InheritableAttr>(
8878 getDLLAttr(Specialization)->clone(getASTContext()));
8879 A->setInherited(true);
8881 dllExportImportClassTemplateSpecialization(*this, Def);
8885 // Fix a TSK_ImplicitInstantiation followed by a
8886 // TSK_ExplicitInstantiationDefinition
8887 bool NewlyDLLExported =
8888 !PreviouslyDLLExported && Specialization->hasAttr<DLLExportAttr>();
8889 if (Old_TSK == TSK_ImplicitInstantiation && NewlyDLLExported &&
8890 (Context.getTargetInfo().getCXXABI().isMicrosoft() ||
8891 Context.getTargetInfo().getTriple().isWindowsItaniumEnvironment())) {
8892 // In the MS ABI, an explicit instantiation definition can add a dll
8893 // attribute to a template with a previous implicit instantiation.
8894 // MinGW doesn't allow this. We limit clang to only adding dllexport, to
8895 // avoid potentially strange codegen behavior. For example, if we extend
8896 // this conditional to dllimport, and we have a source file calling a
8897 // method on an implicitly instantiated template class instance and then
8898 // declaring a dllimport explicit instantiation definition for the same
8899 // template class, the codegen for the method call will not respect the
8900 // dllimport, while it will with cl. The Def will already have the DLL
8901 // attribute, since the Def and Specialization will be the same in the
8902 // case of Old_TSK == TSK_ImplicitInstantiation, and we already added the
8903 // attribute to the Specialization; we just need to make it take effect.
8904 assert(Def == Specialization &&
8905 "Def and Specialization should match for implicit instantiation");
8906 dllExportImportClassTemplateSpecialization(*this, Def);
8909 // Set the template specialization kind. Make sure it is set before
8910 // instantiating the members which will trigger ASTConsumer callbacks.
8911 Specialization->setTemplateSpecializationKind(TSK);
8912 InstantiateClassTemplateSpecializationMembers(TemplateNameLoc, Def, TSK);
8915 // Set the template specialization kind.
8916 Specialization->setTemplateSpecializationKind(TSK);
8919 return Specialization;
8922 // Explicit instantiation of a member class of a class template.
8924 Sema::ActOnExplicitInstantiation(Scope *S, SourceLocation ExternLoc,
8925 SourceLocation TemplateLoc, unsigned TagSpec,
8926 SourceLocation KWLoc, CXXScopeSpec &SS,
8927 IdentifierInfo *Name, SourceLocation NameLoc,
8928 const ParsedAttributesView &Attr) {
8931 bool IsDependent = false;
8932 Decl *TagD = ActOnTag(S, TagSpec, Sema::TUK_Reference,
8933 KWLoc, SS, Name, NameLoc, Attr, AS_none,
8934 /*ModulePrivateLoc=*/SourceLocation(),
8935 MultiTemplateParamsArg(), Owned, IsDependent,
8936 SourceLocation(), false, TypeResult(),
8937 /*IsTypeSpecifier*/false,
8938 /*IsTemplateParamOrArg*/false);
8939 assert(!IsDependent && "explicit instantiation of dependent name not yet handled");
8944 TagDecl *Tag = cast<TagDecl>(TagD);
8945 assert(!Tag->isEnum() && "shouldn't see enumerations here");
8947 if (Tag->isInvalidDecl())
8950 CXXRecordDecl *Record = cast<CXXRecordDecl>(Tag);
8951 CXXRecordDecl *Pattern = Record->getInstantiatedFromMemberClass();
8953 Diag(TemplateLoc, diag::err_explicit_instantiation_nontemplate_type)
8954 << Context.getTypeDeclType(Record);
8955 Diag(Record->getLocation(), diag::note_nontemplate_decl_here);
8959 // C++0x [temp.explicit]p2:
8960 // If the explicit instantiation is for a class or member class, the
8961 // elaborated-type-specifier in the declaration shall include a
8962 // simple-template-id.
8964 // C++98 has the same restriction, just worded differently.
8965 if (!ScopeSpecifierHasTemplateId(SS))
8966 Diag(TemplateLoc, diag::ext_explicit_instantiation_without_qualified_id)
8967 << Record << SS.getRange();
8969 // C++0x [temp.explicit]p2:
8970 // There are two forms of explicit instantiation: an explicit instantiation
8971 // definition and an explicit instantiation declaration. An explicit
8972 // instantiation declaration begins with the extern keyword. [...]
8973 TemplateSpecializationKind TSK
8974 = ExternLoc.isInvalid()? TSK_ExplicitInstantiationDefinition
8975 : TSK_ExplicitInstantiationDeclaration;
8977 // C++0x [temp.explicit]p2:
8978 // [...] An explicit instantiation shall appear in an enclosing
8979 // namespace of its template. [...]
8981 // This is C++ DR 275.
8982 CheckExplicitInstantiationScope(*this, Record, NameLoc, true);
8984 // Verify that it is okay to explicitly instantiate here.
8985 CXXRecordDecl *PrevDecl
8986 = cast_or_null<CXXRecordDecl>(Record->getPreviousDecl());
8987 if (!PrevDecl && Record->getDefinition())
8990 MemberSpecializationInfo *MSInfo = PrevDecl->getMemberSpecializationInfo();
8991 bool HasNoEffect = false;
8992 assert(MSInfo && "No member specialization information?");
8993 if (CheckSpecializationInstantiationRedecl(TemplateLoc, TSK,
8995 MSInfo->getTemplateSpecializationKind(),
8996 MSInfo->getPointOfInstantiation(),
9003 CXXRecordDecl *RecordDef
9004 = cast_or_null<CXXRecordDecl>(Record->getDefinition());
9006 // C++ [temp.explicit]p3:
9007 // A definition of a member class of a class template shall be in scope
9008 // at the point of an explicit instantiation of the member class.
9010 = cast_or_null<CXXRecordDecl>(Pattern->getDefinition());
9012 Diag(TemplateLoc, diag::err_explicit_instantiation_undefined_member)
9013 << 0 << Record->getDeclName() << Record->getDeclContext();
9014 Diag(Pattern->getLocation(), diag::note_forward_declaration)
9018 if (InstantiateClass(NameLoc, Record, Def,
9019 getTemplateInstantiationArgs(Record),
9023 RecordDef = cast_or_null<CXXRecordDecl>(Record->getDefinition());
9029 // Instantiate all of the members of the class.
9030 InstantiateClassMembers(NameLoc, RecordDef,
9031 getTemplateInstantiationArgs(Record), TSK);
9033 if (TSK == TSK_ExplicitInstantiationDefinition)
9034 MarkVTableUsed(NameLoc, RecordDef, true);
9036 // FIXME: We don't have any representation for explicit instantiations of
9037 // member classes. Such a representation is not needed for compilation, but it
9038 // should be available for clients that want to see all of the declarations in
9043 DeclResult Sema::ActOnExplicitInstantiation(Scope *S,
9044 SourceLocation ExternLoc,
9045 SourceLocation TemplateLoc,
9047 // Explicit instantiations always require a name.
9048 // TODO: check if/when DNInfo should replace Name.
9049 DeclarationNameInfo NameInfo = GetNameForDeclarator(D);
9050 DeclarationName Name = NameInfo.getName();
9052 if (!D.isInvalidType())
9053 Diag(D.getDeclSpec().getBeginLoc(),
9054 diag::err_explicit_instantiation_requires_name)
9055 << D.getDeclSpec().getSourceRange() << D.getSourceRange();
9060 // The scope passed in may not be a decl scope. Zip up the scope tree until
9061 // we find one that is.
9062 while ((S->getFlags() & Scope::DeclScope) == 0 ||
9063 (S->getFlags() & Scope::TemplateParamScope) != 0)
9066 // Determine the type of the declaration.
9067 TypeSourceInfo *T = GetTypeForDeclarator(D, S);
9068 QualType R = T->getType();
9073 // A storage-class-specifier shall not be specified in [...] an explicit
9074 // instantiation (14.7.2) directive.
9075 if (D.getDeclSpec().getStorageClassSpec() == DeclSpec::SCS_typedef) {
9076 Diag(D.getIdentifierLoc(), diag::err_explicit_instantiation_of_typedef)
9079 } else if (D.getDeclSpec().getStorageClassSpec()
9080 != DeclSpec::SCS_unspecified) {
9081 // Complain about then remove the storage class specifier.
9082 Diag(D.getIdentifierLoc(), diag::err_explicit_instantiation_storage_class)
9083 << FixItHint::CreateRemoval(D.getDeclSpec().getStorageClassSpecLoc());
9085 D.getMutableDeclSpec().ClearStorageClassSpecs();
9088 // C++0x [temp.explicit]p1:
9089 // [...] An explicit instantiation of a function template shall not use the
9090 // inline or constexpr specifiers.
9091 // Presumably, this also applies to member functions of class templates as
9093 if (D.getDeclSpec().isInlineSpecified())
9094 Diag(D.getDeclSpec().getInlineSpecLoc(),
9095 getLangOpts().CPlusPlus11 ?
9096 diag::err_explicit_instantiation_inline :
9097 diag::warn_explicit_instantiation_inline_0x)
9098 << FixItHint::CreateRemoval(D.getDeclSpec().getInlineSpecLoc());
9099 if (D.getDeclSpec().isConstexprSpecified() && R->isFunctionType())
9100 // FIXME: Add a fix-it to remove the 'constexpr' and add a 'const' if one is
9101 // not already specified.
9102 Diag(D.getDeclSpec().getConstexprSpecLoc(),
9103 diag::err_explicit_instantiation_constexpr);
9105 // A deduction guide is not on the list of entities that can be explicitly
9107 if (Name.getNameKind() == DeclarationName::CXXDeductionGuideName) {
9108 Diag(D.getDeclSpec().getBeginLoc(), diag::err_deduction_guide_specialized)
9109 << /*explicit instantiation*/ 0;
9113 // C++0x [temp.explicit]p2:
9114 // There are two forms of explicit instantiation: an explicit instantiation
9115 // definition and an explicit instantiation declaration. An explicit
9116 // instantiation declaration begins with the extern keyword. [...]
9117 TemplateSpecializationKind TSK
9118 = ExternLoc.isInvalid()? TSK_ExplicitInstantiationDefinition
9119 : TSK_ExplicitInstantiationDeclaration;
9121 LookupResult Previous(*this, NameInfo, LookupOrdinaryName);
9122 LookupParsedName(Previous, S, &D.getCXXScopeSpec());
9124 if (!R->isFunctionType()) {
9125 // C++ [temp.explicit]p1:
9126 // A [...] static data member of a class template can be explicitly
9127 // instantiated from the member definition associated with its class
9129 // C++1y [temp.explicit]p1:
9130 // A [...] variable [...] template specialization can be explicitly
9131 // instantiated from its template.
9132 if (Previous.isAmbiguous())
9135 VarDecl *Prev = Previous.getAsSingle<VarDecl>();
9136 VarTemplateDecl *PrevTemplate = Previous.getAsSingle<VarTemplateDecl>();
9138 if (!PrevTemplate) {
9139 if (!Prev || !Prev->isStaticDataMember()) {
9140 // We expect to see a data data member here.
9141 Diag(D.getIdentifierLoc(), diag::err_explicit_instantiation_not_known)
9143 for (LookupResult::iterator P = Previous.begin(), PEnd = Previous.end();
9145 Diag((*P)->getLocation(), diag::note_explicit_instantiation_here);
9149 if (!Prev->getInstantiatedFromStaticDataMember()) {
9150 // FIXME: Check for explicit specialization?
9151 Diag(D.getIdentifierLoc(),
9152 diag::err_explicit_instantiation_data_member_not_instantiated)
9154 Diag(Prev->getLocation(), diag::note_explicit_instantiation_here);
9155 // FIXME: Can we provide a note showing where this was declared?
9159 // Explicitly instantiate a variable template.
9161 // C++1y [dcl.spec.auto]p6:
9162 // ... A program that uses auto or decltype(auto) in a context not
9163 // explicitly allowed in this section is ill-formed.
9165 // This includes auto-typed variable template instantiations.
9166 if (R->isUndeducedType()) {
9167 Diag(T->getTypeLoc().getBeginLoc(),
9168 diag::err_auto_not_allowed_var_inst);
9172 if (D.getName().getKind() != UnqualifiedIdKind::IK_TemplateId) {
9173 // C++1y [temp.explicit]p3:
9174 // If the explicit instantiation is for a variable, the unqualified-id
9175 // in the declaration shall be a template-id.
9176 Diag(D.getIdentifierLoc(),
9177 diag::err_explicit_instantiation_without_template_id)
9179 Diag(PrevTemplate->getLocation(),
9180 diag::note_explicit_instantiation_here);
9184 // Translate the parser's template argument list into our AST format.
9185 TemplateArgumentListInfo TemplateArgs =
9186 makeTemplateArgumentListInfo(*this, *D.getName().TemplateId);
9188 DeclResult Res = CheckVarTemplateId(PrevTemplate, TemplateLoc,
9189 D.getIdentifierLoc(), TemplateArgs);
9190 if (Res.isInvalid())
9193 // Ignore access control bits, we don't need them for redeclaration
9195 Prev = cast<VarDecl>(Res.get());
9198 // C++0x [temp.explicit]p2:
9199 // If the explicit instantiation is for a member function, a member class
9200 // or a static data member of a class template specialization, the name of
9201 // the class template specialization in the qualified-id for the member
9202 // name shall be a simple-template-id.
9204 // C++98 has the same restriction, just worded differently.
9206 // This does not apply to variable template specializations, where the
9207 // template-id is in the unqualified-id instead.
9208 if (!ScopeSpecifierHasTemplateId(D.getCXXScopeSpec()) && !PrevTemplate)
9209 Diag(D.getIdentifierLoc(),
9210 diag::ext_explicit_instantiation_without_qualified_id)
9211 << Prev << D.getCXXScopeSpec().getRange();
9213 // Check the scope of this explicit instantiation.
9214 CheckExplicitInstantiationScope(*this, Prev, D.getIdentifierLoc(), true);
9216 // Verify that it is okay to explicitly instantiate here.
9217 TemplateSpecializationKind PrevTSK = Prev->getTemplateSpecializationKind();
9218 SourceLocation POI = Prev->getPointOfInstantiation();
9219 bool HasNoEffect = false;
9220 if (CheckSpecializationInstantiationRedecl(D.getIdentifierLoc(), TSK, Prev,
9221 PrevTSK, POI, HasNoEffect))
9225 // Instantiate static data member or variable template.
9226 Prev->setTemplateSpecializationKind(TSK, D.getIdentifierLoc());
9227 // Merge attributes.
9228 ProcessDeclAttributeList(S, Prev, D.getDeclSpec().getAttributes());
9229 if (TSK == TSK_ExplicitInstantiationDefinition)
9230 InstantiateVariableDefinition(D.getIdentifierLoc(), Prev);
9233 // Check the new variable specialization against the parsed input.
9234 if (PrevTemplate && Prev && !Context.hasSameType(Prev->getType(), R)) {
9235 Diag(T->getTypeLoc().getBeginLoc(),
9236 diag::err_invalid_var_template_spec_type)
9237 << 0 << PrevTemplate << R << Prev->getType();
9238 Diag(PrevTemplate->getLocation(), diag::note_template_declared_here)
9239 << 2 << PrevTemplate->getDeclName();
9243 // FIXME: Create an ExplicitInstantiation node?
9244 return (Decl*) nullptr;
9247 // If the declarator is a template-id, translate the parser's template
9248 // argument list into our AST format.
9249 bool HasExplicitTemplateArgs = false;
9250 TemplateArgumentListInfo TemplateArgs;
9251 if (D.getName().getKind() == UnqualifiedIdKind::IK_TemplateId) {
9252 TemplateArgs = makeTemplateArgumentListInfo(*this, *D.getName().TemplateId);
9253 HasExplicitTemplateArgs = true;
9256 // C++ [temp.explicit]p1:
9257 // A [...] function [...] can be explicitly instantiated from its template.
9258 // A member function [...] of a class template can be explicitly
9259 // instantiated from the member definition associated with its class
9261 UnresolvedSet<8> TemplateMatches;
9262 FunctionDecl *NonTemplateMatch = nullptr;
9263 TemplateSpecCandidateSet FailedCandidates(D.getIdentifierLoc());
9264 for (LookupResult::iterator P = Previous.begin(), PEnd = Previous.end();
9266 NamedDecl *Prev = *P;
9267 if (!HasExplicitTemplateArgs) {
9268 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Prev)) {
9269 QualType Adjusted = adjustCCAndNoReturn(R, Method->getType(),
9270 /*AdjustExceptionSpec*/true);
9271 if (Context.hasSameUnqualifiedType(Method->getType(), Adjusted)) {
9272 if (Method->getPrimaryTemplate()) {
9273 TemplateMatches.addDecl(Method, P.getAccess());
9275 // FIXME: Can this assert ever happen? Needs a test.
9276 assert(!NonTemplateMatch && "Multiple NonTemplateMatches");
9277 NonTemplateMatch = Method;
9283 FunctionTemplateDecl *FunTmpl = dyn_cast<FunctionTemplateDecl>(Prev);
9287 TemplateDeductionInfo Info(FailedCandidates.getLocation());
9288 FunctionDecl *Specialization = nullptr;
9289 if (TemplateDeductionResult TDK
9290 = DeduceTemplateArguments(FunTmpl,
9291 (HasExplicitTemplateArgs ? &TemplateArgs
9293 R, Specialization, Info)) {
9294 // Keep track of almost-matches.
9295 FailedCandidates.addCandidate()
9296 .set(P.getPair(), FunTmpl->getTemplatedDecl(),
9297 MakeDeductionFailureInfo(Context, TDK, Info));
9302 // Target attributes are part of the cuda function signature, so
9303 // the cuda target of the instantiated function must match that of its
9304 // template. Given that C++ template deduction does not take
9305 // target attributes into account, we reject candidates here that
9306 // have a different target.
9307 if (LangOpts.CUDA &&
9308 IdentifyCUDATarget(Specialization,
9309 /* IgnoreImplicitHDAttributes = */ true) !=
9310 IdentifyCUDATarget(D.getDeclSpec().getAttributes())) {
9311 FailedCandidates.addCandidate().set(
9312 P.getPair(), FunTmpl->getTemplatedDecl(),
9313 MakeDeductionFailureInfo(Context, TDK_CUDATargetMismatch, Info));
9317 TemplateMatches.addDecl(Specialization, P.getAccess());
9320 FunctionDecl *Specialization = NonTemplateMatch;
9321 if (!Specialization) {
9322 // Find the most specialized function template specialization.
9323 UnresolvedSetIterator Result = getMostSpecialized(
9324 TemplateMatches.begin(), TemplateMatches.end(), FailedCandidates,
9325 D.getIdentifierLoc(),
9326 PDiag(diag::err_explicit_instantiation_not_known) << Name,
9327 PDiag(diag::err_explicit_instantiation_ambiguous) << Name,
9328 PDiag(diag::note_explicit_instantiation_candidate));
9330 if (Result == TemplateMatches.end())
9333 // Ignore access control bits, we don't need them for redeclaration checking.
9334 Specialization = cast<FunctionDecl>(*Result);
9337 // C++11 [except.spec]p4
9338 // In an explicit instantiation an exception-specification may be specified,
9339 // but is not required.
9340 // If an exception-specification is specified in an explicit instantiation
9341 // directive, it shall be compatible with the exception-specifications of
9342 // other declarations of that function.
9343 if (auto *FPT = R->getAs<FunctionProtoType>())
9344 if (FPT->hasExceptionSpec()) {
9346 diag::err_mismatched_exception_spec_explicit_instantiation;
9347 if (getLangOpts().MicrosoftExt)
9348 DiagID = diag::ext_mismatched_exception_spec_explicit_instantiation;
9349 bool Result = CheckEquivalentExceptionSpec(
9350 PDiag(DiagID) << Specialization->getType(),
9351 PDiag(diag::note_explicit_instantiation_here),
9352 Specialization->getType()->getAs<FunctionProtoType>(),
9353 Specialization->getLocation(), FPT, D.getBeginLoc());
9354 // In Microsoft mode, mismatching exception specifications just cause a
9356 if (!getLangOpts().MicrosoftExt && Result)
9360 if (Specialization->getTemplateSpecializationKind() == TSK_Undeclared) {
9361 Diag(D.getIdentifierLoc(),
9362 diag::err_explicit_instantiation_member_function_not_instantiated)
9364 << (Specialization->getTemplateSpecializationKind() ==
9365 TSK_ExplicitSpecialization);
9366 Diag(Specialization->getLocation(), diag::note_explicit_instantiation_here);
9370 FunctionDecl *PrevDecl = Specialization->getPreviousDecl();
9371 if (!PrevDecl && Specialization->isThisDeclarationADefinition())
9372 PrevDecl = Specialization;
9375 bool HasNoEffect = false;
9376 if (CheckSpecializationInstantiationRedecl(D.getIdentifierLoc(), TSK,
9378 PrevDecl->getTemplateSpecializationKind(),
9379 PrevDecl->getPointOfInstantiation(),
9383 // FIXME: We may still want to build some representation of this
9384 // explicit specialization.
9386 return (Decl*) nullptr;
9389 ProcessDeclAttributeList(S, Specialization, D.getDeclSpec().getAttributes());
9391 // In MSVC mode, dllimported explicit instantiation definitions are treated as
9392 // instantiation declarations.
9393 if (TSK == TSK_ExplicitInstantiationDefinition &&
9394 Specialization->hasAttr<DLLImportAttr>() &&
9395 Context.getTargetInfo().getCXXABI().isMicrosoft())
9396 TSK = TSK_ExplicitInstantiationDeclaration;
9398 Specialization->setTemplateSpecializationKind(TSK, D.getIdentifierLoc());
9400 if (Specialization->isDefined()) {
9401 // Let the ASTConsumer know that this function has been explicitly
9402 // instantiated now, and its linkage might have changed.
9403 Consumer.HandleTopLevelDecl(DeclGroupRef(Specialization));
9404 } else if (TSK == TSK_ExplicitInstantiationDefinition)
9405 InstantiateFunctionDefinition(D.getIdentifierLoc(), Specialization);
9407 // C++0x [temp.explicit]p2:
9408 // If the explicit instantiation is for a member function, a member class
9409 // or a static data member of a class template specialization, the name of
9410 // the class template specialization in the qualified-id for the member
9411 // name shall be a simple-template-id.
9413 // C++98 has the same restriction, just worded differently.
9414 FunctionTemplateDecl *FunTmpl = Specialization->getPrimaryTemplate();
9415 if (D.getName().getKind() != UnqualifiedIdKind::IK_TemplateId && !FunTmpl &&
9416 D.getCXXScopeSpec().isSet() &&
9417 !ScopeSpecifierHasTemplateId(D.getCXXScopeSpec()))
9418 Diag(D.getIdentifierLoc(),
9419 diag::ext_explicit_instantiation_without_qualified_id)
9420 << Specialization << D.getCXXScopeSpec().getRange();
9422 CheckExplicitInstantiationScope(*this,
9423 FunTmpl? (NamedDecl *)FunTmpl
9424 : Specialization->getInstantiatedFromMemberFunction(),
9425 D.getIdentifierLoc(),
9426 D.getCXXScopeSpec().isSet());
9428 // FIXME: Create some kind of ExplicitInstantiationDecl here.
9429 return (Decl*) nullptr;
9433 Sema::ActOnDependentTag(Scope *S, unsigned TagSpec, TagUseKind TUK,
9434 const CXXScopeSpec &SS, IdentifierInfo *Name,
9435 SourceLocation TagLoc, SourceLocation NameLoc) {
9436 // This has to hold, because SS is expected to be defined.
9437 assert(Name && "Expected a name in a dependent tag");
9439 NestedNameSpecifier *NNS = SS.getScopeRep();
9443 TagTypeKind Kind = TypeWithKeyword::getTagTypeKindForTypeSpec(TagSpec);
9445 if (TUK == TUK_Declaration || TUK == TUK_Definition) {
9446 Diag(NameLoc, diag::err_dependent_tag_decl)
9447 << (TUK == TUK_Definition) << Kind << SS.getRange();
9451 // Create the resulting type.
9452 ElaboratedTypeKeyword Kwd = TypeWithKeyword::getKeywordForTagTypeKind(Kind);
9453 QualType Result = Context.getDependentNameType(Kwd, NNS, Name);
9455 // Create type-source location information for this type.
9457 DependentNameTypeLoc TL = TLB.push<DependentNameTypeLoc>(Result);
9458 TL.setElaboratedKeywordLoc(TagLoc);
9459 TL.setQualifierLoc(SS.getWithLocInContext(Context));
9460 TL.setNameLoc(NameLoc);
9461 return CreateParsedType(Result, TLB.getTypeSourceInfo(Context, Result));
9465 Sema::ActOnTypenameType(Scope *S, SourceLocation TypenameLoc,
9466 const CXXScopeSpec &SS, const IdentifierInfo &II,
9467 SourceLocation IdLoc) {
9471 if (TypenameLoc.isValid() && S && !S->getTemplateParamParent())
9473 getLangOpts().CPlusPlus11 ?
9474 diag::warn_cxx98_compat_typename_outside_of_template :
9475 diag::ext_typename_outside_of_template)
9476 << FixItHint::CreateRemoval(TypenameLoc);
9478 NestedNameSpecifierLoc QualifierLoc = SS.getWithLocInContext(Context);
9479 QualType T = CheckTypenameType(TypenameLoc.isValid()? ETK_Typename : ETK_None,
9480 TypenameLoc, QualifierLoc, II, IdLoc);
9484 TypeSourceInfo *TSI = Context.CreateTypeSourceInfo(T);
9485 if (isa<DependentNameType>(T)) {
9486 DependentNameTypeLoc TL = TSI->getTypeLoc().castAs<DependentNameTypeLoc>();
9487 TL.setElaboratedKeywordLoc(TypenameLoc);
9488 TL.setQualifierLoc(QualifierLoc);
9489 TL.setNameLoc(IdLoc);
9491 ElaboratedTypeLoc TL = TSI->getTypeLoc().castAs<ElaboratedTypeLoc>();
9492 TL.setElaboratedKeywordLoc(TypenameLoc);
9493 TL.setQualifierLoc(QualifierLoc);
9494 TL.getNamedTypeLoc().castAs<TypeSpecTypeLoc>().setNameLoc(IdLoc);
9497 return CreateParsedType(T, TSI);
9501 Sema::ActOnTypenameType(Scope *S,
9502 SourceLocation TypenameLoc,
9503 const CXXScopeSpec &SS,
9504 SourceLocation TemplateKWLoc,
9505 TemplateTy TemplateIn,
9506 IdentifierInfo *TemplateII,
9507 SourceLocation TemplateIILoc,
9508 SourceLocation LAngleLoc,
9509 ASTTemplateArgsPtr TemplateArgsIn,
9510 SourceLocation RAngleLoc) {
9511 if (TypenameLoc.isValid() && S && !S->getTemplateParamParent())
9513 getLangOpts().CPlusPlus11 ?
9514 diag::warn_cxx98_compat_typename_outside_of_template :
9515 diag::ext_typename_outside_of_template)
9516 << FixItHint::CreateRemoval(TypenameLoc);
9518 // Strangely, non-type results are not ignored by this lookup, so the
9519 // program is ill-formed if it finds an injected-class-name.
9520 if (TypenameLoc.isValid()) {
9522 dyn_cast_or_null<CXXRecordDecl>(computeDeclContext(SS, false));
9523 if (LookupRD && LookupRD->getIdentifier() == TemplateII) {
9525 diag::ext_out_of_line_qualified_id_type_names_constructor)
9526 << TemplateII << 0 /*injected-class-name used as template name*/
9527 << (TemplateKWLoc.isValid() ? 1 : 0 /*'template'/'typename' keyword*/);
9531 // Translate the parser's template argument list in our AST format.
9532 TemplateArgumentListInfo TemplateArgs(LAngleLoc, RAngleLoc);
9533 translateTemplateArguments(TemplateArgsIn, TemplateArgs);
9535 TemplateName Template = TemplateIn.get();
9536 if (DependentTemplateName *DTN = Template.getAsDependentTemplateName()) {
9537 // Construct a dependent template specialization type.
9538 assert(DTN && "dependent template has non-dependent name?");
9539 assert(DTN->getQualifier() == SS.getScopeRep());
9540 QualType T = Context.getDependentTemplateSpecializationType(ETK_Typename,
9541 DTN->getQualifier(),
9542 DTN->getIdentifier(),
9545 // Create source-location information for this type.
9546 TypeLocBuilder Builder;
9547 DependentTemplateSpecializationTypeLoc SpecTL
9548 = Builder.push<DependentTemplateSpecializationTypeLoc>(T);
9549 SpecTL.setElaboratedKeywordLoc(TypenameLoc);
9550 SpecTL.setQualifierLoc(SS.getWithLocInContext(Context));
9551 SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
9552 SpecTL.setTemplateNameLoc(TemplateIILoc);
9553 SpecTL.setLAngleLoc(LAngleLoc);
9554 SpecTL.setRAngleLoc(RAngleLoc);
9555 for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I)
9556 SpecTL.setArgLocInfo(I, TemplateArgs[I].getLocInfo());
9557 return CreateParsedType(T, Builder.getTypeSourceInfo(Context, T));
9560 QualType T = CheckTemplateIdType(Template, TemplateIILoc, TemplateArgs);
9564 // Provide source-location information for the template specialization type.
9565 TypeLocBuilder Builder;
9566 TemplateSpecializationTypeLoc SpecTL
9567 = Builder.push<TemplateSpecializationTypeLoc>(T);
9568 SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
9569 SpecTL.setTemplateNameLoc(TemplateIILoc);
9570 SpecTL.setLAngleLoc(LAngleLoc);
9571 SpecTL.setRAngleLoc(RAngleLoc);
9572 for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I)
9573 SpecTL.setArgLocInfo(I, TemplateArgs[I].getLocInfo());
9575 T = Context.getElaboratedType(ETK_Typename, SS.getScopeRep(), T);
9576 ElaboratedTypeLoc TL = Builder.push<ElaboratedTypeLoc>(T);
9577 TL.setElaboratedKeywordLoc(TypenameLoc);
9578 TL.setQualifierLoc(SS.getWithLocInContext(Context));
9580 TypeSourceInfo *TSI = Builder.getTypeSourceInfo(Context, T);
9581 return CreateParsedType(T, TSI);
9585 /// Determine whether this failed name lookup should be treated as being
9586 /// disabled by a usage of std::enable_if.
9587 static bool isEnableIf(NestedNameSpecifierLoc NNS, const IdentifierInfo &II,
9588 SourceRange &CondRange, Expr *&Cond) {
9589 // We must be looking for a ::type...
9590 if (!II.isStr("type"))
9593 // ... within an explicitly-written template specialization...
9594 if (!NNS || !NNS.getNestedNameSpecifier()->getAsType())
9596 TypeLoc EnableIfTy = NNS.getTypeLoc();
9597 TemplateSpecializationTypeLoc EnableIfTSTLoc =
9598 EnableIfTy.getAs<TemplateSpecializationTypeLoc>();
9599 if (!EnableIfTSTLoc || EnableIfTSTLoc.getNumArgs() == 0)
9601 const TemplateSpecializationType *EnableIfTST = EnableIfTSTLoc.getTypePtr();
9603 // ... which names a complete class template declaration...
9604 const TemplateDecl *EnableIfDecl =
9605 EnableIfTST->getTemplateName().getAsTemplateDecl();
9606 if (!EnableIfDecl || EnableIfTST->isIncompleteType())
9609 // ... called "enable_if".
9610 const IdentifierInfo *EnableIfII =
9611 EnableIfDecl->getDeclName().getAsIdentifierInfo();
9612 if (!EnableIfII || !EnableIfII->isStr("enable_if"))
9615 // Assume the first template argument is the condition.
9616 CondRange = EnableIfTSTLoc.getArgLoc(0).getSourceRange();
9618 // Dig out the condition.
9620 if (EnableIfTSTLoc.getArgLoc(0).getArgument().getKind()
9621 != TemplateArgument::Expression)
9624 Cond = EnableIfTSTLoc.getArgLoc(0).getSourceExpression();
9626 // Ignore Boolean literals; they add no value.
9627 if (isa<CXXBoolLiteralExpr>(Cond->IgnoreParenCasts()))
9633 /// Build the type that describes a C++ typename specifier,
9634 /// e.g., "typename T::type".
9636 Sema::CheckTypenameType(ElaboratedTypeKeyword Keyword,
9637 SourceLocation KeywordLoc,
9638 NestedNameSpecifierLoc QualifierLoc,
9639 const IdentifierInfo &II,
9640 SourceLocation IILoc) {
9642 SS.Adopt(QualifierLoc);
9644 DeclContext *Ctx = computeDeclContext(SS);
9646 // If the nested-name-specifier is dependent and couldn't be
9647 // resolved to a type, build a typename type.
9648 assert(QualifierLoc.getNestedNameSpecifier()->isDependent());
9649 return Context.getDependentNameType(Keyword,
9650 QualifierLoc.getNestedNameSpecifier(),
9654 // If the nested-name-specifier refers to the current instantiation,
9655 // the "typename" keyword itself is superfluous. In C++03, the
9656 // program is actually ill-formed. However, DR 382 (in C++0x CD1)
9657 // allows such extraneous "typename" keywords, and we retroactively
9658 // apply this DR to C++03 code with only a warning. In any case we continue.
9660 if (RequireCompleteDeclContext(SS, Ctx))
9663 DeclarationName Name(&II);
9664 LookupResult Result(*this, Name, IILoc, LookupOrdinaryName);
9665 LookupQualifiedName(Result, Ctx, SS);
9666 unsigned DiagID = 0;
9667 Decl *Referenced = nullptr;
9668 switch (Result.getResultKind()) {
9669 case LookupResult::NotFound: {
9670 // If we're looking up 'type' within a template named 'enable_if', produce
9671 // a more specific diagnostic.
9672 SourceRange CondRange;
9673 Expr *Cond = nullptr;
9674 if (isEnableIf(QualifierLoc, II, CondRange, Cond)) {
9675 // If we have a condition, narrow it down to the specific failed
9679 std::string FailedDescription;
9680 std::tie(FailedCond, FailedDescription) =
9681 findFailedBooleanCondition(Cond);
9683 Diag(FailedCond->getExprLoc(),
9684 diag::err_typename_nested_not_found_requirement)
9685 << FailedDescription
9686 << FailedCond->getSourceRange();
9690 Diag(CondRange.getBegin(), diag::err_typename_nested_not_found_enable_if)
9691 << Ctx << CondRange;
9695 DiagID = diag::err_typename_nested_not_found;
9699 case LookupResult::FoundUnresolvedValue: {
9700 // We found a using declaration that is a value. Most likely, the using
9701 // declaration itself is meant to have the 'typename' keyword.
9702 SourceRange FullRange(KeywordLoc.isValid() ? KeywordLoc : SS.getBeginLoc(),
9704 Diag(IILoc, diag::err_typename_refers_to_using_value_decl)
9705 << Name << Ctx << FullRange;
9706 if (UnresolvedUsingValueDecl *Using
9707 = dyn_cast<UnresolvedUsingValueDecl>(Result.getRepresentativeDecl())){
9708 SourceLocation Loc = Using->getQualifierLoc().getBeginLoc();
9709 Diag(Loc, diag::note_using_value_decl_missing_typename)
9710 << FixItHint::CreateInsertion(Loc, "typename ");
9713 // Fall through to create a dependent typename type, from which we can recover
9717 case LookupResult::NotFoundInCurrentInstantiation:
9718 // Okay, it's a member of an unknown instantiation.
9719 return Context.getDependentNameType(Keyword,
9720 QualifierLoc.getNestedNameSpecifier(),
9723 case LookupResult::Found:
9724 if (TypeDecl *Type = dyn_cast<TypeDecl>(Result.getFoundDecl())) {
9725 // C++ [class.qual]p2:
9726 // In a lookup in which function names are not ignored and the
9727 // nested-name-specifier nominates a class C, if the name specified
9728 // after the nested-name-specifier, when looked up in C, is the
9729 // injected-class-name of C [...] then the name is instead considered
9730 // to name the constructor of class C.
9732 // Unlike in an elaborated-type-specifier, function names are not ignored
9733 // in typename-specifier lookup. However, they are ignored in all the
9734 // contexts where we form a typename type with no keyword (that is, in
9735 // mem-initializer-ids, base-specifiers, and elaborated-type-specifiers).
9737 // FIXME: That's not strictly true: mem-initializer-id lookup does not
9738 // ignore functions, but that appears to be an oversight.
9739 auto *LookupRD = dyn_cast_or_null<CXXRecordDecl>(Ctx);
9740 auto *FoundRD = dyn_cast<CXXRecordDecl>(Type);
9741 if (Keyword == ETK_Typename && LookupRD && FoundRD &&
9742 FoundRD->isInjectedClassName() &&
9743 declaresSameEntity(LookupRD, cast<Decl>(FoundRD->getParent())))
9744 Diag(IILoc, diag::ext_out_of_line_qualified_id_type_names_constructor)
9745 << &II << 1 << 0 /*'typename' keyword used*/;
9747 // We found a type. Build an ElaboratedType, since the
9748 // typename-specifier was just sugar.
9749 MarkAnyDeclReferenced(Type->getLocation(), Type, /*OdrUse=*/false);
9750 return Context.getElaboratedType(Keyword,
9751 QualifierLoc.getNestedNameSpecifier(),
9752 Context.getTypeDeclType(Type));
9755 // C++ [dcl.type.simple]p2:
9756 // A type-specifier of the form
9757 // typename[opt] nested-name-specifier[opt] template-name
9758 // is a placeholder for a deduced class type [...].
9759 if (getLangOpts().CPlusPlus17) {
9760 if (auto *TD = getAsTypeTemplateDecl(Result.getFoundDecl())) {
9761 return Context.getElaboratedType(
9762 Keyword, QualifierLoc.getNestedNameSpecifier(),
9763 Context.getDeducedTemplateSpecializationType(TemplateName(TD),
9764 QualType(), false));
9768 DiagID = diag::err_typename_nested_not_type;
9769 Referenced = Result.getFoundDecl();
9772 case LookupResult::FoundOverloaded:
9773 DiagID = diag::err_typename_nested_not_type;
9774 Referenced = *Result.begin();
9777 case LookupResult::Ambiguous:
9781 // If we get here, it's because name lookup did not find a
9782 // type. Emit an appropriate diagnostic and return an error.
9783 SourceRange FullRange(KeywordLoc.isValid() ? KeywordLoc : SS.getBeginLoc(),
9785 Diag(IILoc, DiagID) << FullRange << Name << Ctx;
9787 Diag(Referenced->getLocation(), diag::note_typename_refers_here)
9793 // See Sema::RebuildTypeInCurrentInstantiation
9794 class CurrentInstantiationRebuilder
9795 : public TreeTransform<CurrentInstantiationRebuilder> {
9797 DeclarationName Entity;
9800 typedef TreeTransform<CurrentInstantiationRebuilder> inherited;
9802 CurrentInstantiationRebuilder(Sema &SemaRef,
9804 DeclarationName Entity)
9805 : TreeTransform<CurrentInstantiationRebuilder>(SemaRef),
9806 Loc(Loc), Entity(Entity) { }
9808 /// Determine whether the given type \p T has already been
9811 /// For the purposes of type reconstruction, a type has already been
9812 /// transformed if it is NULL or if it is not dependent.
9813 bool AlreadyTransformed(QualType T) {
9814 return T.isNull() || !T->isDependentType();
9817 /// Returns the location of the entity whose type is being
9819 SourceLocation getBaseLocation() { return Loc; }
9821 /// Returns the name of the entity whose type is being rebuilt.
9822 DeclarationName getBaseEntity() { return Entity; }
9824 /// Sets the "base" location and entity when that
9825 /// information is known based on another transformation.
9826 void setBase(SourceLocation Loc, DeclarationName Entity) {
9828 this->Entity = Entity;
9831 ExprResult TransformLambdaExpr(LambdaExpr *E) {
9832 // Lambdas never need to be transformed.
9836 } // end anonymous namespace
9838 /// Rebuilds a type within the context of the current instantiation.
9840 /// The type \p T is part of the type of an out-of-line member definition of
9841 /// a class template (or class template partial specialization) that was parsed
9842 /// and constructed before we entered the scope of the class template (or
9843 /// partial specialization thereof). This routine will rebuild that type now
9844 /// that we have entered the declarator's scope, which may produce different
9845 /// canonical types, e.g.,
9848 /// template<typename T>
9850 /// typedef T* pointer;
9854 /// template<typename T>
9855 /// typename X<T>::pointer X<T>::data() { ... }
9858 /// Here, the type "typename X<T>::pointer" will be created as a DependentNameType,
9859 /// since we do not know that we can look into X<T> when we parsed the type.
9860 /// This function will rebuild the type, performing the lookup of "pointer"
9861 /// in X<T> and returning an ElaboratedType whose canonical type is the same
9862 /// as the canonical type of T*, allowing the return types of the out-of-line
9863 /// definition and the declaration to match.
9864 TypeSourceInfo *Sema::RebuildTypeInCurrentInstantiation(TypeSourceInfo *T,
9866 DeclarationName Name) {
9867 if (!T || !T->getType()->isDependentType())
9870 CurrentInstantiationRebuilder Rebuilder(*this, Loc, Name);
9871 return Rebuilder.TransformType(T);
9874 ExprResult Sema::RebuildExprInCurrentInstantiation(Expr *E) {
9875 CurrentInstantiationRebuilder Rebuilder(*this, E->getExprLoc(),
9877 return Rebuilder.TransformExpr(E);
9880 bool Sema::RebuildNestedNameSpecifierInCurrentInstantiation(CXXScopeSpec &SS) {
9884 NestedNameSpecifierLoc QualifierLoc = SS.getWithLocInContext(Context);
9885 CurrentInstantiationRebuilder Rebuilder(*this, SS.getRange().getBegin(),
9887 NestedNameSpecifierLoc Rebuilt
9888 = Rebuilder.TransformNestedNameSpecifierLoc(QualifierLoc);
9896 /// Rebuild the template parameters now that we know we're in a current
9898 bool Sema::RebuildTemplateParamsInCurrentInstantiation(
9899 TemplateParameterList *Params) {
9900 for (unsigned I = 0, N = Params->size(); I != N; ++I) {
9901 Decl *Param = Params->getParam(I);
9903 // There is nothing to rebuild in a type parameter.
9904 if (isa<TemplateTypeParmDecl>(Param))
9907 // Rebuild the template parameter list of a template template parameter.
9908 if (TemplateTemplateParmDecl *TTP
9909 = dyn_cast<TemplateTemplateParmDecl>(Param)) {
9910 if (RebuildTemplateParamsInCurrentInstantiation(
9911 TTP->getTemplateParameters()))
9917 // Rebuild the type of a non-type template parameter.
9918 NonTypeTemplateParmDecl *NTTP = cast<NonTypeTemplateParmDecl>(Param);
9919 TypeSourceInfo *NewTSI
9920 = RebuildTypeInCurrentInstantiation(NTTP->getTypeSourceInfo(),
9921 NTTP->getLocation(),
9922 NTTP->getDeclName());
9926 if (NewTSI->getType()->isUndeducedType()) {
9927 // C++17 [temp.dep.expr]p3:
9928 // An id-expression is type-dependent if it contains
9929 // - an identifier associated by name lookup with a non-type
9930 // template-parameter declared with a type that contains a
9931 // placeholder type (7.1.7.4),
9932 NewTSI = SubstAutoTypeSourceInfo(NewTSI, Context.DependentTy);
9935 if (NewTSI != NTTP->getTypeSourceInfo()) {
9936 NTTP->setTypeSourceInfo(NewTSI);
9937 NTTP->setType(NewTSI->getType());
9944 /// Produces a formatted string that describes the binding of
9945 /// template parameters to template arguments.
9947 Sema::getTemplateArgumentBindingsText(const TemplateParameterList *Params,
9948 const TemplateArgumentList &Args) {
9949 return getTemplateArgumentBindingsText(Params, Args.data(), Args.size());
9953 Sema::getTemplateArgumentBindingsText(const TemplateParameterList *Params,
9954 const TemplateArgument *Args,
9956 SmallString<128> Str;
9957 llvm::raw_svector_ostream Out(Str);
9959 if (!Params || Params->size() == 0 || NumArgs == 0)
9960 return std::string();
9962 for (unsigned I = 0, N = Params->size(); I != N; ++I) {
9971 if (const IdentifierInfo *Id = Params->getParam(I)->getIdentifier()) {
9972 Out << Id->getName();
9978 Args[I].print(getPrintingPolicy(), Out);
9985 void Sema::MarkAsLateParsedTemplate(FunctionDecl *FD, Decl *FnD,
9986 CachedTokens &Toks) {
9990 auto LPT = llvm::make_unique<LateParsedTemplate>();
9992 // Take tokens to avoid allocations
9993 LPT->Toks.swap(Toks);
9995 LateParsedTemplateMap.insert(std::make_pair(FD, std::move(LPT)));
9997 FD->setLateTemplateParsed(true);
10000 void Sema::UnmarkAsLateParsedTemplate(FunctionDecl *FD) {
10003 FD->setLateTemplateParsed(false);
10006 bool Sema::IsInsideALocalClassWithinATemplateFunction() {
10007 DeclContext *DC = CurContext;
10010 if (CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(CurContext)) {
10011 const FunctionDecl *FD = RD->isLocalClass();
10012 return (FD && FD->getTemplatedKind() != FunctionDecl::TK_NonTemplate);
10013 } else if (DC->isTranslationUnit() || DC->isNamespace())
10016 DC = DC->getParent();
10022 /// Walk the path from which a declaration was instantiated, and check
10023 /// that every explicit specialization along that path is visible. This enforces
10024 /// C++ [temp.expl.spec]/6:
10026 /// If a template, a member template or a member of a class template is
10027 /// explicitly specialized then that specialization shall be declared before
10028 /// the first use of that specialization that would cause an implicit
10029 /// instantiation to take place, in every translation unit in which such a
10030 /// use occurs; no diagnostic is required.
10032 /// and also C++ [temp.class.spec]/1:
10034 /// A partial specialization shall be declared before the first use of a
10035 /// class template specialization that would make use of the partial
10036 /// specialization as the result of an implicit or explicit instantiation
10037 /// in every translation unit in which such a use occurs; no diagnostic is
10039 class ExplicitSpecializationVisibilityChecker {
10041 SourceLocation Loc;
10042 llvm::SmallVector<Module *, 8> Modules;
10045 ExplicitSpecializationVisibilityChecker(Sema &S, SourceLocation Loc)
10046 : S(S), Loc(Loc) {}
10048 void check(NamedDecl *ND) {
10049 if (auto *FD = dyn_cast<FunctionDecl>(ND))
10050 return checkImpl(FD);
10051 if (auto *RD = dyn_cast<CXXRecordDecl>(ND))
10052 return checkImpl(RD);
10053 if (auto *VD = dyn_cast<VarDecl>(ND))
10054 return checkImpl(VD);
10055 if (auto *ED = dyn_cast<EnumDecl>(ND))
10056 return checkImpl(ED);
10060 void diagnose(NamedDecl *D, bool IsPartialSpec) {
10061 auto Kind = IsPartialSpec ? Sema::MissingImportKind::PartialSpecialization
10062 : Sema::MissingImportKind::ExplicitSpecialization;
10063 const bool Recover = true;
10065 // If we got a custom set of modules (because only a subset of the
10066 // declarations are interesting), use them, otherwise let
10067 // diagnoseMissingImport intelligently pick some.
10068 if (Modules.empty())
10069 S.diagnoseMissingImport(Loc, D, Kind, Recover);
10071 S.diagnoseMissingImport(Loc, D, D->getLocation(), Modules, Kind, Recover);
10074 // Check a specific declaration. There are three problematic cases:
10076 // 1) The declaration is an explicit specialization of a template
10078 // 2) The declaration is an explicit specialization of a member of an
10079 // templated class.
10080 // 3) The declaration is an instantiation of a template, and that template
10081 // is an explicit specialization of a member of a templated class.
10083 // We don't need to go any deeper than that, as the instantiation of the
10084 // surrounding class / etc is not triggered by whatever triggered this
10085 // instantiation, and thus should be checked elsewhere.
10086 template<typename SpecDecl>
10087 void checkImpl(SpecDecl *Spec) {
10088 bool IsHiddenExplicitSpecialization = false;
10089 if (Spec->getTemplateSpecializationKind() == TSK_ExplicitSpecialization) {
10090 IsHiddenExplicitSpecialization =
10091 Spec->getMemberSpecializationInfo()
10092 ? !S.hasVisibleMemberSpecialization(Spec, &Modules)
10093 : !S.hasVisibleExplicitSpecialization(Spec, &Modules);
10095 checkInstantiated(Spec);
10098 if (IsHiddenExplicitSpecialization)
10099 diagnose(Spec->getMostRecentDecl(), false);
10102 void checkInstantiated(FunctionDecl *FD) {
10103 if (auto *TD = FD->getPrimaryTemplate())
10107 void checkInstantiated(CXXRecordDecl *RD) {
10108 auto *SD = dyn_cast<ClassTemplateSpecializationDecl>(RD);
10112 auto From = SD->getSpecializedTemplateOrPartial();
10113 if (auto *TD = From.dyn_cast<ClassTemplateDecl *>())
10115 else if (auto *TD =
10116 From.dyn_cast<ClassTemplatePartialSpecializationDecl *>()) {
10117 if (!S.hasVisibleDeclaration(TD))
10118 diagnose(TD, true);
10123 void checkInstantiated(VarDecl *RD) {
10124 auto *SD = dyn_cast<VarTemplateSpecializationDecl>(RD);
10128 auto From = SD->getSpecializedTemplateOrPartial();
10129 if (auto *TD = From.dyn_cast<VarTemplateDecl *>())
10131 else if (auto *TD =
10132 From.dyn_cast<VarTemplatePartialSpecializationDecl *>()) {
10133 if (!S.hasVisibleDeclaration(TD))
10134 diagnose(TD, true);
10139 void checkInstantiated(EnumDecl *FD) {}
10141 template<typename TemplDecl>
10142 void checkTemplate(TemplDecl *TD) {
10143 if (TD->isMemberSpecialization()) {
10144 if (!S.hasVisibleMemberSpecialization(TD, &Modules))
10145 diagnose(TD->getMostRecentDecl(), false);
10149 } // end anonymous namespace
10151 void Sema::checkSpecializationVisibility(SourceLocation Loc, NamedDecl *Spec) {
10152 if (!getLangOpts().Modules)
10155 ExplicitSpecializationVisibilityChecker(*this, Loc).check(Spec);
10158 /// Check whether a template partial specialization that we've discovered
10159 /// is hidden, and produce suitable diagnostics if so.
10160 void Sema::checkPartialSpecializationVisibility(SourceLocation Loc,
10162 llvm::SmallVector<Module *, 8> Modules;
10163 if (!hasVisibleDeclaration(Spec, &Modules))
10164 diagnoseMissingImport(Loc, Spec, Spec->getLocation(), Modules,
10165 MissingImportKind::PartialSpecialization,