[Flang] remove whole-archive option for AIX linker (#76039)
[llvm-project.git] / clang / lib / Sema / SemaTemplate.cpp
blob5fcc39ec700522837a8a2415964b730b737b8d16
1 //===------- SemaTemplate.cpp - Semantic Analysis for C++ Templates -------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //===----------------------------------------------------------------------===//
7 //
8 // This file implements semantic analysis for C++ templates.
9 //===----------------------------------------------------------------------===//
11 #include "TreeTransform.h"
12 #include "clang/AST/ASTConsumer.h"
13 #include "clang/AST/ASTContext.h"
14 #include "clang/AST/Decl.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/TemplateName.h"
21 #include "clang/AST/TypeVisitor.h"
22 #include "clang/Basic/Builtins.h"
23 #include "clang/Basic/DiagnosticSema.h"
24 #include "clang/Basic/LangOptions.h"
25 #include "clang/Basic/PartialDiagnostic.h"
26 #include "clang/Basic/SourceLocation.h"
27 #include "clang/Basic/Stack.h"
28 #include "clang/Basic/TargetInfo.h"
29 #include "clang/Sema/DeclSpec.h"
30 #include "clang/Sema/EnterExpressionEvaluationContext.h"
31 #include "clang/Sema/Initialization.h"
32 #include "clang/Sema/Lookup.h"
33 #include "clang/Sema/Overload.h"
34 #include "clang/Sema/ParsedTemplate.h"
35 #include "clang/Sema/Scope.h"
36 #include "clang/Sema/SemaInternal.h"
37 #include "clang/Sema/Template.h"
38 #include "clang/Sema/TemplateDeduction.h"
39 #include "llvm/ADT/SmallBitVector.h"
40 #include "llvm/ADT/SmallString.h"
41 #include "llvm/ADT/StringExtras.h"
43 #include <iterator>
44 #include <optional>
45 using namespace clang;
46 using namespace sema;
48 // Exported for use by Parser.
49 SourceRange
50 clang::getTemplateParamsRange(TemplateParameterList const * const *Ps,
51 unsigned N) {
52 if (!N) return SourceRange();
53 return SourceRange(Ps[0]->getTemplateLoc(), Ps[N-1]->getRAngleLoc());
56 unsigned Sema::getTemplateDepth(Scope *S) const {
57 unsigned Depth = 0;
59 // Each template parameter scope represents one level of template parameter
60 // depth.
61 for (Scope *TempParamScope = S->getTemplateParamParent(); TempParamScope;
62 TempParamScope = TempParamScope->getParent()->getTemplateParamParent()) {
63 ++Depth;
66 // Note that there are template parameters with the given depth.
67 auto ParamsAtDepth = [&](unsigned D) { Depth = std::max(Depth, D + 1); };
69 // Look for parameters of an enclosing generic lambda. We don't create a
70 // template parameter scope for these.
71 for (FunctionScopeInfo *FSI : getFunctionScopes()) {
72 if (auto *LSI = dyn_cast<LambdaScopeInfo>(FSI)) {
73 if (!LSI->TemplateParams.empty()) {
74 ParamsAtDepth(LSI->AutoTemplateParameterDepth);
75 break;
77 if (LSI->GLTemplateParameterList) {
78 ParamsAtDepth(LSI->GLTemplateParameterList->getDepth());
79 break;
84 // Look for parameters of an enclosing terse function template. We don't
85 // create a template parameter scope for these either.
86 for (const InventedTemplateParameterInfo &Info :
87 getInventedParameterInfos()) {
88 if (!Info.TemplateParams.empty()) {
89 ParamsAtDepth(Info.AutoTemplateParameterDepth);
90 break;
94 return Depth;
97 /// \brief Determine whether the declaration found is acceptable as the name
98 /// of a template and, if so, return that template declaration. Otherwise,
99 /// returns null.
101 /// Note that this may return an UnresolvedUsingValueDecl if AllowDependent
102 /// is true. In all other cases it will return a TemplateDecl (or null).
103 NamedDecl *Sema::getAsTemplateNameDecl(NamedDecl *D,
104 bool AllowFunctionTemplates,
105 bool AllowDependent) {
106 D = D->getUnderlyingDecl();
108 if (isa<TemplateDecl>(D)) {
109 if (!AllowFunctionTemplates && isa<FunctionTemplateDecl>(D))
110 return nullptr;
112 return D;
115 if (const auto *Record = dyn_cast<CXXRecordDecl>(D)) {
116 // C++ [temp.local]p1:
117 // Like normal (non-template) classes, class templates have an
118 // injected-class-name (Clause 9). The injected-class-name
119 // can be used with or without a template-argument-list. When
120 // it is used without a template-argument-list, it is
121 // equivalent to the injected-class-name followed by the
122 // template-parameters of the class template enclosed in
123 // <>. When it is used with a template-argument-list, it
124 // refers to the specified class template specialization,
125 // which could be the current specialization or another
126 // specialization.
127 if (Record->isInjectedClassName()) {
128 Record = cast<CXXRecordDecl>(Record->getDeclContext());
129 if (Record->getDescribedClassTemplate())
130 return Record->getDescribedClassTemplate();
132 if (const auto *Spec = dyn_cast<ClassTemplateSpecializationDecl>(Record))
133 return Spec->getSpecializedTemplate();
136 return nullptr;
139 // 'using Dependent::foo;' can resolve to a template name.
140 // 'using typename Dependent::foo;' cannot (not even if 'foo' is an
141 // injected-class-name).
142 if (AllowDependent && isa<UnresolvedUsingValueDecl>(D))
143 return D;
145 return nullptr;
148 void Sema::FilterAcceptableTemplateNames(LookupResult &R,
149 bool AllowFunctionTemplates,
150 bool AllowDependent) {
151 LookupResult::Filter filter = R.makeFilter();
152 while (filter.hasNext()) {
153 NamedDecl *Orig = filter.next();
154 if (!getAsTemplateNameDecl(Orig, AllowFunctionTemplates, AllowDependent))
155 filter.erase();
157 filter.done();
160 bool Sema::hasAnyAcceptableTemplateNames(LookupResult &R,
161 bool AllowFunctionTemplates,
162 bool AllowDependent,
163 bool AllowNonTemplateFunctions) {
164 for (LookupResult::iterator I = R.begin(), IEnd = R.end(); I != IEnd; ++I) {
165 if (getAsTemplateNameDecl(*I, AllowFunctionTemplates, AllowDependent))
166 return true;
167 if (AllowNonTemplateFunctions &&
168 isa<FunctionDecl>((*I)->getUnderlyingDecl()))
169 return true;
172 return false;
175 TemplateNameKind Sema::isTemplateName(Scope *S,
176 CXXScopeSpec &SS,
177 bool hasTemplateKeyword,
178 const UnqualifiedId &Name,
179 ParsedType ObjectTypePtr,
180 bool EnteringContext,
181 TemplateTy &TemplateResult,
182 bool &MemberOfUnknownSpecialization,
183 bool Disambiguation) {
184 assert(getLangOpts().CPlusPlus && "No template names in C!");
186 DeclarationName TName;
187 MemberOfUnknownSpecialization = false;
189 switch (Name.getKind()) {
190 case UnqualifiedIdKind::IK_Identifier:
191 TName = DeclarationName(Name.Identifier);
192 break;
194 case UnqualifiedIdKind::IK_OperatorFunctionId:
195 TName = Context.DeclarationNames.getCXXOperatorName(
196 Name.OperatorFunctionId.Operator);
197 break;
199 case UnqualifiedIdKind::IK_LiteralOperatorId:
200 TName = Context.DeclarationNames.getCXXLiteralOperatorName(Name.Identifier);
201 break;
203 default:
204 return TNK_Non_template;
207 QualType ObjectType = ObjectTypePtr.get();
209 AssumedTemplateKind AssumedTemplate;
210 LookupResult R(*this, TName, Name.getBeginLoc(), LookupOrdinaryName);
211 if (LookupTemplateName(R, S, SS, ObjectType, EnteringContext,
212 MemberOfUnknownSpecialization, SourceLocation(),
213 &AssumedTemplate,
214 /*AllowTypoCorrection=*/!Disambiguation))
215 return TNK_Non_template;
217 if (AssumedTemplate != AssumedTemplateKind::None) {
218 TemplateResult = TemplateTy::make(Context.getAssumedTemplateName(TName));
219 // Let the parser know whether we found nothing or found functions; if we
220 // found nothing, we want to more carefully check whether this is actually
221 // a function template name versus some other kind of undeclared identifier.
222 return AssumedTemplate == AssumedTemplateKind::FoundNothing
223 ? TNK_Undeclared_template
224 : TNK_Function_template;
227 if (R.empty())
228 return TNK_Non_template;
230 NamedDecl *D = nullptr;
231 UsingShadowDecl *FoundUsingShadow = dyn_cast<UsingShadowDecl>(*R.begin());
232 if (R.isAmbiguous()) {
233 // If we got an ambiguity involving a non-function template, treat this
234 // as a template name, and pick an arbitrary template for error recovery.
235 bool AnyFunctionTemplates = false;
236 for (NamedDecl *FoundD : R) {
237 if (NamedDecl *FoundTemplate = getAsTemplateNameDecl(FoundD)) {
238 if (isa<FunctionTemplateDecl>(FoundTemplate))
239 AnyFunctionTemplates = true;
240 else {
241 D = FoundTemplate;
242 FoundUsingShadow = dyn_cast<UsingShadowDecl>(FoundD);
243 break;
248 // If we didn't find any templates at all, this isn't a template name.
249 // Leave the ambiguity for a later lookup to diagnose.
250 if (!D && !AnyFunctionTemplates) {
251 R.suppressDiagnostics();
252 return TNK_Non_template;
255 // If the only templates were function templates, filter out the rest.
256 // We'll diagnose the ambiguity later.
257 if (!D)
258 FilterAcceptableTemplateNames(R);
261 // At this point, we have either picked a single template name declaration D
262 // or we have a non-empty set of results R containing either one template name
263 // declaration or a set of function templates.
265 TemplateName Template;
266 TemplateNameKind TemplateKind;
268 unsigned ResultCount = R.end() - R.begin();
269 if (!D && ResultCount > 1) {
270 // We assume that we'll preserve the qualifier from a function
271 // template name in other ways.
272 Template = Context.getOverloadedTemplateName(R.begin(), R.end());
273 TemplateKind = TNK_Function_template;
275 // We'll do this lookup again later.
276 R.suppressDiagnostics();
277 } else {
278 if (!D) {
279 D = getAsTemplateNameDecl(*R.begin());
280 assert(D && "unambiguous result is not a template name");
283 if (isa<UnresolvedUsingValueDecl>(D)) {
284 // We don't yet know whether this is a template-name or not.
285 MemberOfUnknownSpecialization = true;
286 return TNK_Non_template;
289 TemplateDecl *TD = cast<TemplateDecl>(D);
290 Template =
291 FoundUsingShadow ? TemplateName(FoundUsingShadow) : TemplateName(TD);
292 assert(!FoundUsingShadow || FoundUsingShadow->getTargetDecl() == TD);
293 if (SS.isSet() && !SS.isInvalid()) {
294 NestedNameSpecifier *Qualifier = SS.getScopeRep();
295 Template = Context.getQualifiedTemplateName(Qualifier, hasTemplateKeyword,
296 Template);
299 if (isa<FunctionTemplateDecl>(TD)) {
300 TemplateKind = TNK_Function_template;
302 // We'll do this lookup again later.
303 R.suppressDiagnostics();
304 } else {
305 assert(isa<ClassTemplateDecl>(TD) || isa<TemplateTemplateParmDecl>(TD) ||
306 isa<TypeAliasTemplateDecl>(TD) || isa<VarTemplateDecl>(TD) ||
307 isa<BuiltinTemplateDecl>(TD) || isa<ConceptDecl>(TD));
308 TemplateKind =
309 isa<VarTemplateDecl>(TD) ? TNK_Var_template :
310 isa<ConceptDecl>(TD) ? TNK_Concept_template :
311 TNK_Type_template;
315 TemplateResult = TemplateTy::make(Template);
316 return TemplateKind;
319 bool Sema::isDeductionGuideName(Scope *S, const IdentifierInfo &Name,
320 SourceLocation NameLoc, CXXScopeSpec &SS,
321 ParsedTemplateTy *Template /*=nullptr*/) {
322 bool MemberOfUnknownSpecialization = false;
324 // We could use redeclaration lookup here, but we don't need to: the
325 // syntactic form of a deduction guide is enough to identify it even
326 // if we can't look up the template name at all.
327 LookupResult R(*this, DeclarationName(&Name), NameLoc, LookupOrdinaryName);
328 if (LookupTemplateName(R, S, SS, /*ObjectType*/ QualType(),
329 /*EnteringContext*/ false,
330 MemberOfUnknownSpecialization))
331 return false;
333 if (R.empty()) return false;
334 if (R.isAmbiguous()) {
335 // FIXME: Diagnose an ambiguity if we find at least one template.
336 R.suppressDiagnostics();
337 return false;
340 // We only treat template-names that name type templates as valid deduction
341 // guide names.
342 TemplateDecl *TD = R.getAsSingle<TemplateDecl>();
343 if (!TD || !getAsTypeTemplateDecl(TD))
344 return false;
346 if (Template)
347 *Template = TemplateTy::make(TemplateName(TD));
348 return true;
351 bool Sema::DiagnoseUnknownTemplateName(const IdentifierInfo &II,
352 SourceLocation IILoc,
353 Scope *S,
354 const CXXScopeSpec *SS,
355 TemplateTy &SuggestedTemplate,
356 TemplateNameKind &SuggestedKind) {
357 // We can't recover unless there's a dependent scope specifier preceding the
358 // template name.
359 // FIXME: Typo correction?
360 if (!SS || !SS->isSet() || !isDependentScopeSpecifier(*SS) ||
361 computeDeclContext(*SS))
362 return false;
364 // The code is missing a 'template' keyword prior to the dependent template
365 // name.
366 NestedNameSpecifier *Qualifier = (NestedNameSpecifier*)SS->getScopeRep();
367 Diag(IILoc, diag::err_template_kw_missing)
368 << Qualifier << II.getName()
369 << FixItHint::CreateInsertion(IILoc, "template ");
370 SuggestedTemplate
371 = TemplateTy::make(Context.getDependentTemplateName(Qualifier, &II));
372 SuggestedKind = TNK_Dependent_template_name;
373 return true;
376 bool Sema::LookupTemplateName(LookupResult &Found,
377 Scope *S, CXXScopeSpec &SS,
378 QualType ObjectType,
379 bool EnteringContext,
380 bool &MemberOfUnknownSpecialization,
381 RequiredTemplateKind RequiredTemplate,
382 AssumedTemplateKind *ATK,
383 bool AllowTypoCorrection) {
384 if (ATK)
385 *ATK = AssumedTemplateKind::None;
387 if (SS.isInvalid())
388 return true;
390 Found.setTemplateNameLookup(true);
392 // Determine where to perform name lookup
393 MemberOfUnknownSpecialization = false;
394 DeclContext *LookupCtx = nullptr;
395 bool IsDependent = false;
396 if (!ObjectType.isNull()) {
397 // This nested-name-specifier occurs in a member access expression, e.g.,
398 // x->B::f, and we are looking into the type of the object.
399 assert(SS.isEmpty() && "ObjectType and scope specifier cannot coexist");
400 LookupCtx = computeDeclContext(ObjectType);
401 IsDependent = !LookupCtx && ObjectType->isDependentType();
402 assert((IsDependent || !ObjectType->isIncompleteType() ||
403 !ObjectType->getAs<TagType>() ||
404 ObjectType->castAs<TagType>()->isBeingDefined()) &&
405 "Caller should have completed object type");
407 // Template names cannot appear inside an Objective-C class or object type
408 // or a vector type.
410 // FIXME: This is wrong. For example:
412 // template<typename T> using Vec = T __attribute__((ext_vector_type(4)));
413 // Vec<int> vi;
414 // vi.Vec<int>::~Vec<int>();
416 // ... should be accepted but we will not treat 'Vec' as a template name
417 // here. The right thing to do would be to check if the name is a valid
418 // vector component name, and look up a template name if not. And similarly
419 // for lookups into Objective-C class and object types, where the same
420 // problem can arise.
421 if (ObjectType->isObjCObjectOrInterfaceType() ||
422 ObjectType->isVectorType()) {
423 Found.clear();
424 return false;
426 } else if (SS.isNotEmpty()) {
427 // This nested-name-specifier occurs after another nested-name-specifier,
428 // so long into the context associated with the prior nested-name-specifier.
429 LookupCtx = computeDeclContext(SS, EnteringContext);
430 IsDependent = !LookupCtx && isDependentScopeSpecifier(SS);
432 // The declaration context must be complete.
433 if (LookupCtx && RequireCompleteDeclContext(SS, LookupCtx))
434 return true;
437 bool ObjectTypeSearchedInScope = false;
438 bool AllowFunctionTemplatesInLookup = true;
439 if (LookupCtx) {
440 // Perform "qualified" name lookup into the declaration context we
441 // computed, which is either the type of the base of a member access
442 // expression or the declaration context associated with a prior
443 // nested-name-specifier.
444 LookupQualifiedName(Found, LookupCtx);
446 // FIXME: The C++ standard does not clearly specify what happens in the
447 // case where the object type is dependent, and implementations vary. In
448 // Clang, we treat a name after a . or -> as a template-name if lookup
449 // finds a non-dependent member or member of the current instantiation that
450 // is a type template, or finds no such members and lookup in the context
451 // of the postfix-expression finds a type template. In the latter case, the
452 // name is nonetheless dependent, and we may resolve it to a member of an
453 // unknown specialization when we come to instantiate the template.
454 IsDependent |= Found.wasNotFoundInCurrentInstantiation();
457 if (SS.isEmpty() && (ObjectType.isNull() || Found.empty())) {
458 // C++ [basic.lookup.classref]p1:
459 // In a class member access expression (5.2.5), if the . or -> token is
460 // immediately followed by an identifier followed by a <, the
461 // identifier must be looked up to determine whether the < is the
462 // beginning of a template argument list (14.2) or a less-than operator.
463 // The identifier is first looked up in the class of the object
464 // expression. If the identifier is not found, it is then looked up in
465 // the context of the entire postfix-expression and shall name a class
466 // template.
467 if (S)
468 LookupName(Found, S);
470 if (!ObjectType.isNull()) {
471 // FIXME: We should filter out all non-type templates here, particularly
472 // variable templates and concepts. But the exclusion of alias templates
473 // and template template parameters is a wording defect.
474 AllowFunctionTemplatesInLookup = false;
475 ObjectTypeSearchedInScope = true;
478 IsDependent |= Found.wasNotFoundInCurrentInstantiation();
481 if (Found.isAmbiguous())
482 return false;
484 if (ATK && SS.isEmpty() && ObjectType.isNull() &&
485 !RequiredTemplate.hasTemplateKeyword()) {
486 // C++2a [temp.names]p2:
487 // A name is also considered to refer to a template if it is an
488 // unqualified-id followed by a < and name lookup finds either one or more
489 // functions or finds nothing.
491 // To keep our behavior consistent, we apply the "finds nothing" part in
492 // all language modes, and diagnose the empty lookup in ActOnCallExpr if we
493 // successfully form a call to an undeclared template-id.
494 bool AllFunctions =
495 getLangOpts().CPlusPlus20 && llvm::all_of(Found, [](NamedDecl *ND) {
496 return isa<FunctionDecl>(ND->getUnderlyingDecl());
498 if (AllFunctions || (Found.empty() && !IsDependent)) {
499 // If lookup found any functions, or if this is a name that can only be
500 // used for a function, then strongly assume this is a function
501 // template-id.
502 *ATK = (Found.empty() && Found.getLookupName().isIdentifier())
503 ? AssumedTemplateKind::FoundNothing
504 : AssumedTemplateKind::FoundFunctions;
505 Found.clear();
506 return false;
510 if (Found.empty() && !IsDependent && AllowTypoCorrection) {
511 // If we did not find any names, and this is not a disambiguation, attempt
512 // to correct any typos.
513 DeclarationName Name = Found.getLookupName();
514 Found.clear();
515 // Simple filter callback that, for keywords, only accepts the C++ *_cast
516 DefaultFilterCCC FilterCCC{};
517 FilterCCC.WantTypeSpecifiers = false;
518 FilterCCC.WantExpressionKeywords = false;
519 FilterCCC.WantRemainingKeywords = false;
520 FilterCCC.WantCXXNamedCasts = true;
521 if (TypoCorrection Corrected =
522 CorrectTypo(Found.getLookupNameInfo(), Found.getLookupKind(), S,
523 &SS, FilterCCC, CTK_ErrorRecovery, LookupCtx)) {
524 if (auto *ND = Corrected.getFoundDecl())
525 Found.addDecl(ND);
526 FilterAcceptableTemplateNames(Found);
527 if (Found.isAmbiguous()) {
528 Found.clear();
529 } else if (!Found.empty()) {
530 Found.setLookupName(Corrected.getCorrection());
531 if (LookupCtx) {
532 std::string CorrectedStr(Corrected.getAsString(getLangOpts()));
533 bool DroppedSpecifier = Corrected.WillReplaceSpecifier() &&
534 Name.getAsString() == CorrectedStr;
535 diagnoseTypo(Corrected, PDiag(diag::err_no_member_template_suggest)
536 << Name << LookupCtx << DroppedSpecifier
537 << SS.getRange());
538 } else {
539 diagnoseTypo(Corrected, PDiag(diag::err_no_template_suggest) << Name);
545 NamedDecl *ExampleLookupResult =
546 Found.empty() ? nullptr : Found.getRepresentativeDecl();
547 FilterAcceptableTemplateNames(Found, AllowFunctionTemplatesInLookup);
548 if (Found.empty()) {
549 if (IsDependent) {
550 MemberOfUnknownSpecialization = true;
551 return false;
554 // If a 'template' keyword was used, a lookup that finds only non-template
555 // names is an error.
556 if (ExampleLookupResult && RequiredTemplate) {
557 Diag(Found.getNameLoc(), diag::err_template_kw_refers_to_non_template)
558 << Found.getLookupName() << SS.getRange()
559 << RequiredTemplate.hasTemplateKeyword()
560 << RequiredTemplate.getTemplateKeywordLoc();
561 Diag(ExampleLookupResult->getUnderlyingDecl()->getLocation(),
562 diag::note_template_kw_refers_to_non_template)
563 << Found.getLookupName();
564 return true;
567 return false;
570 if (S && !ObjectType.isNull() && !ObjectTypeSearchedInScope &&
571 !getLangOpts().CPlusPlus11) {
572 // C++03 [basic.lookup.classref]p1:
573 // [...] If the lookup in the class of the object expression finds a
574 // template, the name is also looked up in the context of the entire
575 // postfix-expression and [...]
577 // Note: C++11 does not perform this second lookup.
578 LookupResult FoundOuter(*this, Found.getLookupName(), Found.getNameLoc(),
579 LookupOrdinaryName);
580 FoundOuter.setTemplateNameLookup(true);
581 LookupName(FoundOuter, S);
582 // FIXME: We silently accept an ambiguous lookup here, in violation of
583 // [basic.lookup]/1.
584 FilterAcceptableTemplateNames(FoundOuter, /*AllowFunctionTemplates=*/false);
586 NamedDecl *OuterTemplate;
587 if (FoundOuter.empty()) {
588 // - if the name is not found, the name found in the class of the
589 // object expression is used, otherwise
590 } else if (FoundOuter.isAmbiguous() || !FoundOuter.isSingleResult() ||
591 !(OuterTemplate =
592 getAsTemplateNameDecl(FoundOuter.getFoundDecl()))) {
593 // - if the name is found in the context of the entire
594 // postfix-expression and does not name a class template, the name
595 // found in the class of the object expression is used, otherwise
596 FoundOuter.clear();
597 } else if (!Found.isSuppressingAmbiguousDiagnostics()) {
598 // - if the name found is a class template, it must refer to the same
599 // entity as the one found in the class of the object expression,
600 // otherwise the program is ill-formed.
601 if (!Found.isSingleResult() ||
602 getAsTemplateNameDecl(Found.getFoundDecl())->getCanonicalDecl() !=
603 OuterTemplate->getCanonicalDecl()) {
604 Diag(Found.getNameLoc(),
605 diag::ext_nested_name_member_ref_lookup_ambiguous)
606 << Found.getLookupName()
607 << ObjectType;
608 Diag(Found.getRepresentativeDecl()->getLocation(),
609 diag::note_ambig_member_ref_object_type)
610 << ObjectType;
611 Diag(FoundOuter.getFoundDecl()->getLocation(),
612 diag::note_ambig_member_ref_scope);
614 // Recover by taking the template that we found in the object
615 // expression's type.
620 return false;
623 void Sema::diagnoseExprIntendedAsTemplateName(Scope *S, ExprResult TemplateName,
624 SourceLocation Less,
625 SourceLocation Greater) {
626 if (TemplateName.isInvalid())
627 return;
629 DeclarationNameInfo NameInfo;
630 CXXScopeSpec SS;
631 LookupNameKind LookupKind;
633 DeclContext *LookupCtx = nullptr;
634 NamedDecl *Found = nullptr;
635 bool MissingTemplateKeyword = false;
637 // Figure out what name we looked up.
638 if (auto *DRE = dyn_cast<DeclRefExpr>(TemplateName.get())) {
639 NameInfo = DRE->getNameInfo();
640 SS.Adopt(DRE->getQualifierLoc());
641 LookupKind = LookupOrdinaryName;
642 Found = DRE->getFoundDecl();
643 } else if (auto *ME = dyn_cast<MemberExpr>(TemplateName.get())) {
644 NameInfo = ME->getMemberNameInfo();
645 SS.Adopt(ME->getQualifierLoc());
646 LookupKind = LookupMemberName;
647 LookupCtx = ME->getBase()->getType()->getAsCXXRecordDecl();
648 Found = ME->getMemberDecl();
649 } else if (auto *DSDRE =
650 dyn_cast<DependentScopeDeclRefExpr>(TemplateName.get())) {
651 NameInfo = DSDRE->getNameInfo();
652 SS.Adopt(DSDRE->getQualifierLoc());
653 MissingTemplateKeyword = true;
654 } else if (auto *DSME =
655 dyn_cast<CXXDependentScopeMemberExpr>(TemplateName.get())) {
656 NameInfo = DSME->getMemberNameInfo();
657 SS.Adopt(DSME->getQualifierLoc());
658 MissingTemplateKeyword = true;
659 } else {
660 llvm_unreachable("unexpected kind of potential template name");
663 // If this is a dependent-scope lookup, diagnose that the 'template' keyword
664 // was missing.
665 if (MissingTemplateKeyword) {
666 Diag(NameInfo.getBeginLoc(), diag::err_template_kw_missing)
667 << "" << NameInfo.getName().getAsString() << SourceRange(Less, Greater);
668 return;
671 // Try to correct the name by looking for templates and C++ named casts.
672 struct TemplateCandidateFilter : CorrectionCandidateCallback {
673 Sema &S;
674 TemplateCandidateFilter(Sema &S) : S(S) {
675 WantTypeSpecifiers = false;
676 WantExpressionKeywords = false;
677 WantRemainingKeywords = false;
678 WantCXXNamedCasts = true;
680 bool ValidateCandidate(const TypoCorrection &Candidate) override {
681 if (auto *ND = Candidate.getCorrectionDecl())
682 return S.getAsTemplateNameDecl(ND);
683 return Candidate.isKeyword();
686 std::unique_ptr<CorrectionCandidateCallback> clone() override {
687 return std::make_unique<TemplateCandidateFilter>(*this);
691 DeclarationName Name = NameInfo.getName();
692 TemplateCandidateFilter CCC(*this);
693 if (TypoCorrection Corrected = CorrectTypo(NameInfo, LookupKind, S, &SS, CCC,
694 CTK_ErrorRecovery, LookupCtx)) {
695 auto *ND = Corrected.getFoundDecl();
696 if (ND)
697 ND = getAsTemplateNameDecl(ND);
698 if (ND || Corrected.isKeyword()) {
699 if (LookupCtx) {
700 std::string CorrectedStr(Corrected.getAsString(getLangOpts()));
701 bool DroppedSpecifier = Corrected.WillReplaceSpecifier() &&
702 Name.getAsString() == CorrectedStr;
703 diagnoseTypo(Corrected,
704 PDiag(diag::err_non_template_in_member_template_id_suggest)
705 << Name << LookupCtx << DroppedSpecifier
706 << SS.getRange(), false);
707 } else {
708 diagnoseTypo(Corrected,
709 PDiag(diag::err_non_template_in_template_id_suggest)
710 << Name, false);
712 if (Found)
713 Diag(Found->getLocation(),
714 diag::note_non_template_in_template_id_found);
715 return;
719 Diag(NameInfo.getLoc(), diag::err_non_template_in_template_id)
720 << Name << SourceRange(Less, Greater);
721 if (Found)
722 Diag(Found->getLocation(), diag::note_non_template_in_template_id_found);
725 /// ActOnDependentIdExpression - Handle a dependent id-expression that
726 /// was just parsed. This is only possible with an explicit scope
727 /// specifier naming a dependent type.
728 ExprResult
729 Sema::ActOnDependentIdExpression(const CXXScopeSpec &SS,
730 SourceLocation TemplateKWLoc,
731 const DeclarationNameInfo &NameInfo,
732 bool isAddressOfOperand,
733 const TemplateArgumentListInfo *TemplateArgs) {
734 DeclContext *DC = getFunctionLevelDeclContext();
736 // C++11 [expr.prim.general]p12:
737 // An id-expression that denotes a non-static data member or non-static
738 // member function of a class can only be used:
739 // (...)
740 // - if that id-expression denotes a non-static data member and it
741 // appears in an unevaluated operand.
743 // If this might be the case, form a DependentScopeDeclRefExpr instead of a
744 // CXXDependentScopeMemberExpr. The former can instantiate to either
745 // DeclRefExpr or MemberExpr depending on lookup results, while the latter is
746 // always a MemberExpr.
747 bool MightBeCxx11UnevalField =
748 getLangOpts().CPlusPlus11 && isUnevaluatedContext();
750 // Check if the nested name specifier is an enum type.
751 bool IsEnum = false;
752 if (NestedNameSpecifier *NNS = SS.getScopeRep())
753 IsEnum = isa_and_nonnull<EnumType>(NNS->getAsType());
755 if (!MightBeCxx11UnevalField && !isAddressOfOperand && !IsEnum &&
756 isa<CXXMethodDecl>(DC) &&
757 cast<CXXMethodDecl>(DC)->isImplicitObjectMemberFunction()) {
758 QualType ThisType = cast<CXXMethodDecl>(DC)->getThisType().getNonReferenceType();
760 // Since the 'this' expression is synthesized, we don't need to
761 // perform the double-lookup check.
762 NamedDecl *FirstQualifierInScope = nullptr;
764 return CXXDependentScopeMemberExpr::Create(
765 Context, /*This=*/nullptr, ThisType,
766 /*IsArrow=*/!Context.getLangOpts().HLSL,
767 /*Op=*/SourceLocation(), SS.getWithLocInContext(Context), TemplateKWLoc,
768 FirstQualifierInScope, NameInfo, TemplateArgs);
771 return BuildDependentDeclRefExpr(SS, TemplateKWLoc, NameInfo, TemplateArgs);
774 ExprResult
775 Sema::BuildDependentDeclRefExpr(const CXXScopeSpec &SS,
776 SourceLocation TemplateKWLoc,
777 const DeclarationNameInfo &NameInfo,
778 const TemplateArgumentListInfo *TemplateArgs) {
779 // DependentScopeDeclRefExpr::Create requires a valid QualifierLoc
780 NestedNameSpecifierLoc QualifierLoc = SS.getWithLocInContext(Context);
781 if (!QualifierLoc)
782 return ExprError();
784 return DependentScopeDeclRefExpr::Create(
785 Context, QualifierLoc, TemplateKWLoc, NameInfo, TemplateArgs);
789 /// Determine whether we would be unable to instantiate this template (because
790 /// it either has no definition, or is in the process of being instantiated).
791 bool Sema::DiagnoseUninstantiableTemplate(SourceLocation PointOfInstantiation,
792 NamedDecl *Instantiation,
793 bool InstantiatedFromMember,
794 const NamedDecl *Pattern,
795 const NamedDecl *PatternDef,
796 TemplateSpecializationKind TSK,
797 bool Complain /*= true*/) {
798 assert(isa<TagDecl>(Instantiation) || isa<FunctionDecl>(Instantiation) ||
799 isa<VarDecl>(Instantiation));
801 bool IsEntityBeingDefined = false;
802 if (const TagDecl *TD = dyn_cast_or_null<TagDecl>(PatternDef))
803 IsEntityBeingDefined = TD->isBeingDefined();
805 if (PatternDef && !IsEntityBeingDefined) {
806 NamedDecl *SuggestedDef = nullptr;
807 if (!hasReachableDefinition(const_cast<NamedDecl *>(PatternDef),
808 &SuggestedDef,
809 /*OnlyNeedComplete*/ false)) {
810 // If we're allowed to diagnose this and recover, do so.
811 bool Recover = Complain && !isSFINAEContext();
812 if (Complain)
813 diagnoseMissingImport(PointOfInstantiation, SuggestedDef,
814 Sema::MissingImportKind::Definition, Recover);
815 return !Recover;
817 return false;
820 if (!Complain || (PatternDef && PatternDef->isInvalidDecl()))
821 return true;
823 QualType InstantiationTy;
824 if (TagDecl *TD = dyn_cast<TagDecl>(Instantiation))
825 InstantiationTy = Context.getTypeDeclType(TD);
826 if (PatternDef) {
827 Diag(PointOfInstantiation,
828 diag::err_template_instantiate_within_definition)
829 << /*implicit|explicit*/(TSK != TSK_ImplicitInstantiation)
830 << InstantiationTy;
831 // Not much point in noting the template declaration here, since
832 // we're lexically inside it.
833 Instantiation->setInvalidDecl();
834 } else if (InstantiatedFromMember) {
835 if (isa<FunctionDecl>(Instantiation)) {
836 Diag(PointOfInstantiation,
837 diag::err_explicit_instantiation_undefined_member)
838 << /*member function*/ 1 << Instantiation->getDeclName()
839 << Instantiation->getDeclContext();
840 Diag(Pattern->getLocation(), diag::note_explicit_instantiation_here);
841 } else {
842 assert(isa<TagDecl>(Instantiation) && "Must be a TagDecl!");
843 Diag(PointOfInstantiation,
844 diag::err_implicit_instantiate_member_undefined)
845 << InstantiationTy;
846 Diag(Pattern->getLocation(), diag::note_member_declared_at);
848 } else {
849 if (isa<FunctionDecl>(Instantiation)) {
850 Diag(PointOfInstantiation,
851 diag::err_explicit_instantiation_undefined_func_template)
852 << Pattern;
853 Diag(Pattern->getLocation(), diag::note_explicit_instantiation_here);
854 } else if (isa<TagDecl>(Instantiation)) {
855 Diag(PointOfInstantiation, diag::err_template_instantiate_undefined)
856 << (TSK != TSK_ImplicitInstantiation)
857 << InstantiationTy;
858 NoteTemplateLocation(*Pattern);
859 } else {
860 assert(isa<VarDecl>(Instantiation) && "Must be a VarDecl!");
861 if (isa<VarTemplateSpecializationDecl>(Instantiation)) {
862 Diag(PointOfInstantiation,
863 diag::err_explicit_instantiation_undefined_var_template)
864 << Instantiation;
865 Instantiation->setInvalidDecl();
866 } else
867 Diag(PointOfInstantiation,
868 diag::err_explicit_instantiation_undefined_member)
869 << /*static data member*/ 2 << Instantiation->getDeclName()
870 << Instantiation->getDeclContext();
871 Diag(Pattern->getLocation(), diag::note_explicit_instantiation_here);
875 // In general, Instantiation isn't marked invalid to get more than one
876 // error for multiple undefined instantiations. But the code that does
877 // explicit declaration -> explicit definition conversion can't handle
878 // invalid declarations, so mark as invalid in that case.
879 if (TSK == TSK_ExplicitInstantiationDeclaration)
880 Instantiation->setInvalidDecl();
881 return true;
884 /// DiagnoseTemplateParameterShadow - Produce a diagnostic complaining
885 /// that the template parameter 'PrevDecl' is being shadowed by a new
886 /// declaration at location Loc. Returns true to indicate that this is
887 /// an error, and false otherwise.
888 void Sema::DiagnoseTemplateParameterShadow(SourceLocation Loc, Decl *PrevDecl) {
889 assert(PrevDecl->isTemplateParameter() && "Not a template parameter");
891 // C++ [temp.local]p4:
892 // A template-parameter shall not be redeclared within its
893 // scope (including nested scopes).
895 // Make this a warning when MSVC compatibility is requested.
896 unsigned DiagId = getLangOpts().MSVCCompat ? diag::ext_template_param_shadow
897 : diag::err_template_param_shadow;
898 const auto *ND = cast<NamedDecl>(PrevDecl);
899 Diag(Loc, DiagId) << ND->getDeclName();
900 NoteTemplateParameterLocation(*ND);
903 /// AdjustDeclIfTemplate - If the given decl happens to be a template, reset
904 /// the parameter D to reference the templated declaration and return a pointer
905 /// to the template declaration. Otherwise, do nothing to D and return null.
906 TemplateDecl *Sema::AdjustDeclIfTemplate(Decl *&D) {
907 if (TemplateDecl *Temp = dyn_cast_or_null<TemplateDecl>(D)) {
908 D = Temp->getTemplatedDecl();
909 return Temp;
911 return nullptr;
914 ParsedTemplateArgument ParsedTemplateArgument::getTemplatePackExpansion(
915 SourceLocation EllipsisLoc) const {
916 assert(Kind == Template &&
917 "Only template template arguments can be pack expansions here");
918 assert(getAsTemplate().get().containsUnexpandedParameterPack() &&
919 "Template template argument pack expansion without packs");
920 ParsedTemplateArgument Result(*this);
921 Result.EllipsisLoc = EllipsisLoc;
922 return Result;
925 static TemplateArgumentLoc translateTemplateArgument(Sema &SemaRef,
926 const ParsedTemplateArgument &Arg) {
928 switch (Arg.getKind()) {
929 case ParsedTemplateArgument::Type: {
930 TypeSourceInfo *DI;
931 QualType T = SemaRef.GetTypeFromParser(Arg.getAsType(), &DI);
932 if (!DI)
933 DI = SemaRef.Context.getTrivialTypeSourceInfo(T, Arg.getLocation());
934 return TemplateArgumentLoc(TemplateArgument(T), DI);
937 case ParsedTemplateArgument::NonType: {
938 Expr *E = static_cast<Expr *>(Arg.getAsExpr());
939 return TemplateArgumentLoc(TemplateArgument(E), E);
942 case ParsedTemplateArgument::Template: {
943 TemplateName Template = Arg.getAsTemplate().get();
944 TemplateArgument TArg;
945 if (Arg.getEllipsisLoc().isValid())
946 TArg = TemplateArgument(Template, std::optional<unsigned int>());
947 else
948 TArg = Template;
949 return TemplateArgumentLoc(
950 SemaRef.Context, TArg,
951 Arg.getScopeSpec().getWithLocInContext(SemaRef.Context),
952 Arg.getLocation(), Arg.getEllipsisLoc());
956 llvm_unreachable("Unhandled parsed template argument");
959 /// Translates template arguments as provided by the parser
960 /// into template arguments used by semantic analysis.
961 void Sema::translateTemplateArguments(const ASTTemplateArgsPtr &TemplateArgsIn,
962 TemplateArgumentListInfo &TemplateArgs) {
963 for (unsigned I = 0, Last = TemplateArgsIn.size(); I != Last; ++I)
964 TemplateArgs.addArgument(translateTemplateArgument(*this,
965 TemplateArgsIn[I]));
968 static void maybeDiagnoseTemplateParameterShadow(Sema &SemaRef, Scope *S,
969 SourceLocation Loc,
970 IdentifierInfo *Name) {
971 NamedDecl *PrevDecl = SemaRef.LookupSingleName(
972 S, Name, Loc, Sema::LookupOrdinaryName, Sema::ForVisibleRedeclaration);
973 if (PrevDecl && PrevDecl->isTemplateParameter())
974 SemaRef.DiagnoseTemplateParameterShadow(Loc, PrevDecl);
977 /// Convert a parsed type into a parsed template argument. This is mostly
978 /// trivial, except that we may have parsed a C++17 deduced class template
979 /// specialization type, in which case we should form a template template
980 /// argument instead of a type template argument.
981 ParsedTemplateArgument Sema::ActOnTemplateTypeArgument(TypeResult ParsedType) {
982 TypeSourceInfo *TInfo;
983 QualType T = GetTypeFromParser(ParsedType.get(), &TInfo);
984 if (T.isNull())
985 return ParsedTemplateArgument();
986 assert(TInfo && "template argument with no location");
988 // If we might have formed a deduced template specialization type, convert
989 // it to a template template argument.
990 if (getLangOpts().CPlusPlus17) {
991 TypeLoc TL = TInfo->getTypeLoc();
992 SourceLocation EllipsisLoc;
993 if (auto PET = TL.getAs<PackExpansionTypeLoc>()) {
994 EllipsisLoc = PET.getEllipsisLoc();
995 TL = PET.getPatternLoc();
998 CXXScopeSpec SS;
999 if (auto ET = TL.getAs<ElaboratedTypeLoc>()) {
1000 SS.Adopt(ET.getQualifierLoc());
1001 TL = ET.getNamedTypeLoc();
1004 if (auto DTST = TL.getAs<DeducedTemplateSpecializationTypeLoc>()) {
1005 TemplateName Name = DTST.getTypePtr()->getTemplateName();
1006 if (SS.isSet())
1007 Name = Context.getQualifiedTemplateName(SS.getScopeRep(),
1008 /*HasTemplateKeyword=*/false,
1009 Name);
1010 ParsedTemplateArgument Result(SS, TemplateTy::make(Name),
1011 DTST.getTemplateNameLoc());
1012 if (EllipsisLoc.isValid())
1013 Result = Result.getTemplatePackExpansion(EllipsisLoc);
1014 return Result;
1018 // This is a normal type template argument. Note, if the type template
1019 // argument is an injected-class-name for a template, it has a dual nature
1020 // and can be used as either a type or a template. We handle that in
1021 // convertTypeTemplateArgumentToTemplate.
1022 return ParsedTemplateArgument(ParsedTemplateArgument::Type,
1023 ParsedType.get().getAsOpaquePtr(),
1024 TInfo->getTypeLoc().getBeginLoc());
1027 /// ActOnTypeParameter - Called when a C++ template type parameter
1028 /// (e.g., "typename T") has been parsed. Typename specifies whether
1029 /// the keyword "typename" was used to declare the type parameter
1030 /// (otherwise, "class" was used), and KeyLoc is the location of the
1031 /// "class" or "typename" keyword. ParamName is the name of the
1032 /// parameter (NULL indicates an unnamed template parameter) and
1033 /// ParamNameLoc is the location of the parameter name (if any).
1034 /// If the type parameter has a default argument, it will be added
1035 /// later via ActOnTypeParameterDefault.
1036 NamedDecl *Sema::ActOnTypeParameter(Scope *S, bool Typename,
1037 SourceLocation EllipsisLoc,
1038 SourceLocation KeyLoc,
1039 IdentifierInfo *ParamName,
1040 SourceLocation ParamNameLoc,
1041 unsigned Depth, unsigned Position,
1042 SourceLocation EqualLoc,
1043 ParsedType DefaultArg,
1044 bool HasTypeConstraint) {
1045 assert(S->isTemplateParamScope() &&
1046 "Template type parameter not in template parameter scope!");
1048 bool IsParameterPack = EllipsisLoc.isValid();
1049 TemplateTypeParmDecl *Param
1050 = TemplateTypeParmDecl::Create(Context, Context.getTranslationUnitDecl(),
1051 KeyLoc, ParamNameLoc, Depth, Position,
1052 ParamName, Typename, IsParameterPack,
1053 HasTypeConstraint);
1054 Param->setAccess(AS_public);
1056 if (Param->isParameterPack())
1057 if (auto *LSI = getEnclosingLambda())
1058 LSI->LocalPacks.push_back(Param);
1060 if (ParamName) {
1061 maybeDiagnoseTemplateParameterShadow(*this, S, ParamNameLoc, ParamName);
1063 // Add the template parameter into the current scope.
1064 S->AddDecl(Param);
1065 IdResolver.AddDecl(Param);
1068 // C++0x [temp.param]p9:
1069 // A default template-argument may be specified for any kind of
1070 // template-parameter that is not a template parameter pack.
1071 if (DefaultArg && IsParameterPack) {
1072 Diag(EqualLoc, diag::err_template_param_pack_default_arg);
1073 DefaultArg = nullptr;
1076 // Handle the default argument, if provided.
1077 if (DefaultArg) {
1078 TypeSourceInfo *DefaultTInfo;
1079 GetTypeFromParser(DefaultArg, &DefaultTInfo);
1081 assert(DefaultTInfo && "expected source information for type");
1083 // Check for unexpanded parameter packs.
1084 if (DiagnoseUnexpandedParameterPack(ParamNameLoc, DefaultTInfo,
1085 UPPC_DefaultArgument))
1086 return Param;
1088 // Check the template argument itself.
1089 if (CheckTemplateArgument(DefaultTInfo)) {
1090 Param->setInvalidDecl();
1091 return Param;
1094 Param->setDefaultArgument(DefaultTInfo);
1097 return Param;
1100 /// Convert the parser's template argument list representation into our form.
1101 static TemplateArgumentListInfo
1102 makeTemplateArgumentListInfo(Sema &S, TemplateIdAnnotation &TemplateId) {
1103 TemplateArgumentListInfo TemplateArgs(TemplateId.LAngleLoc,
1104 TemplateId.RAngleLoc);
1105 ASTTemplateArgsPtr TemplateArgsPtr(TemplateId.getTemplateArgs(),
1106 TemplateId.NumArgs);
1107 S.translateTemplateArguments(TemplateArgsPtr, TemplateArgs);
1108 return TemplateArgs;
1111 bool Sema::CheckTypeConstraint(TemplateIdAnnotation *TypeConstr) {
1113 TemplateName TN = TypeConstr->Template.get();
1114 ConceptDecl *CD = cast<ConceptDecl>(TN.getAsTemplateDecl());
1116 // C++2a [temp.param]p4:
1117 // [...] The concept designated by a type-constraint shall be a type
1118 // concept ([temp.concept]).
1119 if (!CD->isTypeConcept()) {
1120 Diag(TypeConstr->TemplateNameLoc,
1121 diag::err_type_constraint_non_type_concept);
1122 return true;
1125 bool WereArgsSpecified = TypeConstr->LAngleLoc.isValid();
1127 if (!WereArgsSpecified &&
1128 CD->getTemplateParameters()->getMinRequiredArguments() > 1) {
1129 Diag(TypeConstr->TemplateNameLoc,
1130 diag::err_type_constraint_missing_arguments)
1131 << CD;
1132 return true;
1134 return false;
1137 bool Sema::ActOnTypeConstraint(const CXXScopeSpec &SS,
1138 TemplateIdAnnotation *TypeConstr,
1139 TemplateTypeParmDecl *ConstrainedParameter,
1140 SourceLocation EllipsisLoc) {
1141 return BuildTypeConstraint(SS, TypeConstr, ConstrainedParameter, EllipsisLoc,
1142 false);
1145 bool Sema::BuildTypeConstraint(const CXXScopeSpec &SS,
1146 TemplateIdAnnotation *TypeConstr,
1147 TemplateTypeParmDecl *ConstrainedParameter,
1148 SourceLocation EllipsisLoc,
1149 bool AllowUnexpandedPack) {
1151 if (CheckTypeConstraint(TypeConstr))
1152 return true;
1154 TemplateName TN = TypeConstr->Template.get();
1155 ConceptDecl *CD = cast<ConceptDecl>(TN.getAsTemplateDecl());
1157 DeclarationNameInfo ConceptName(DeclarationName(TypeConstr->Name),
1158 TypeConstr->TemplateNameLoc);
1160 TemplateArgumentListInfo TemplateArgs;
1161 if (TypeConstr->LAngleLoc.isValid()) {
1162 TemplateArgs =
1163 makeTemplateArgumentListInfo(*this, *TypeConstr);
1165 if (EllipsisLoc.isInvalid() && !AllowUnexpandedPack) {
1166 for (TemplateArgumentLoc Arg : TemplateArgs.arguments()) {
1167 if (DiagnoseUnexpandedParameterPack(Arg, UPPC_TypeConstraint))
1168 return true;
1172 return AttachTypeConstraint(
1173 SS.isSet() ? SS.getWithLocInContext(Context) : NestedNameSpecifierLoc(),
1174 ConceptName, CD,
1175 TypeConstr->LAngleLoc.isValid() ? &TemplateArgs : nullptr,
1176 ConstrainedParameter, EllipsisLoc);
1179 template<typename ArgumentLocAppender>
1180 static ExprResult formImmediatelyDeclaredConstraint(
1181 Sema &S, NestedNameSpecifierLoc NS, DeclarationNameInfo NameInfo,
1182 ConceptDecl *NamedConcept, SourceLocation LAngleLoc,
1183 SourceLocation RAngleLoc, QualType ConstrainedType,
1184 SourceLocation ParamNameLoc, ArgumentLocAppender Appender,
1185 SourceLocation EllipsisLoc) {
1187 TemplateArgumentListInfo ConstraintArgs;
1188 ConstraintArgs.addArgument(
1189 S.getTrivialTemplateArgumentLoc(TemplateArgument(ConstrainedType),
1190 /*NTTPType=*/QualType(), ParamNameLoc));
1192 ConstraintArgs.setRAngleLoc(RAngleLoc);
1193 ConstraintArgs.setLAngleLoc(LAngleLoc);
1194 Appender(ConstraintArgs);
1196 // C++2a [temp.param]p4:
1197 // [...] This constraint-expression E is called the immediately-declared
1198 // constraint of T. [...]
1199 CXXScopeSpec SS;
1200 SS.Adopt(NS);
1201 ExprResult ImmediatelyDeclaredConstraint = S.CheckConceptTemplateId(
1202 SS, /*TemplateKWLoc=*/SourceLocation(), NameInfo,
1203 /*FoundDecl=*/NamedConcept, NamedConcept, &ConstraintArgs);
1204 if (ImmediatelyDeclaredConstraint.isInvalid() || !EllipsisLoc.isValid())
1205 return ImmediatelyDeclaredConstraint;
1207 // C++2a [temp.param]p4:
1208 // [...] If T is not a pack, then E is E', otherwise E is (E' && ...).
1210 // We have the following case:
1212 // template<typename T> concept C1 = true;
1213 // template<C1... T> struct s1;
1215 // The constraint: (C1<T> && ...)
1217 // Note that the type of C1<T> is known to be 'bool', so we don't need to do
1218 // any unqualified lookups for 'operator&&' here.
1219 return S.BuildCXXFoldExpr(/*UnqualifiedLookup=*/nullptr,
1220 /*LParenLoc=*/SourceLocation(),
1221 ImmediatelyDeclaredConstraint.get(), BO_LAnd,
1222 EllipsisLoc, /*RHS=*/nullptr,
1223 /*RParenLoc=*/SourceLocation(),
1224 /*NumExpansions=*/std::nullopt);
1227 /// Attach a type-constraint to a template parameter.
1228 /// \returns true if an error occurred. This can happen if the
1229 /// immediately-declared constraint could not be formed (e.g. incorrect number
1230 /// of arguments for the named concept).
1231 bool Sema::AttachTypeConstraint(NestedNameSpecifierLoc NS,
1232 DeclarationNameInfo NameInfo,
1233 ConceptDecl *NamedConcept,
1234 const TemplateArgumentListInfo *TemplateArgs,
1235 TemplateTypeParmDecl *ConstrainedParameter,
1236 SourceLocation EllipsisLoc) {
1237 // C++2a [temp.param]p4:
1238 // [...] If Q is of the form C<A1, ..., An>, then let E' be
1239 // C<T, A1, ..., An>. Otherwise, let E' be C<T>. [...]
1240 const ASTTemplateArgumentListInfo *ArgsAsWritten =
1241 TemplateArgs ? ASTTemplateArgumentListInfo::Create(Context,
1242 *TemplateArgs) : nullptr;
1244 QualType ParamAsArgument(ConstrainedParameter->getTypeForDecl(), 0);
1246 ExprResult ImmediatelyDeclaredConstraint =
1247 formImmediatelyDeclaredConstraint(
1248 *this, NS, NameInfo, NamedConcept,
1249 TemplateArgs ? TemplateArgs->getLAngleLoc() : SourceLocation(),
1250 TemplateArgs ? TemplateArgs->getRAngleLoc() : SourceLocation(),
1251 ParamAsArgument, ConstrainedParameter->getLocation(),
1252 [&] (TemplateArgumentListInfo &ConstraintArgs) {
1253 if (TemplateArgs)
1254 for (const auto &ArgLoc : TemplateArgs->arguments())
1255 ConstraintArgs.addArgument(ArgLoc);
1256 }, EllipsisLoc);
1257 if (ImmediatelyDeclaredConstraint.isInvalid())
1258 return true;
1260 auto *CL = ConceptReference::Create(Context, /*NNS=*/NS,
1261 /*TemplateKWLoc=*/SourceLocation{},
1262 /*ConceptNameInfo=*/NameInfo,
1263 /*FoundDecl=*/NamedConcept,
1264 /*NamedConcept=*/NamedConcept,
1265 /*ArgsWritten=*/ArgsAsWritten);
1266 ConstrainedParameter->setTypeConstraint(CL,
1267 ImmediatelyDeclaredConstraint.get());
1268 return false;
1271 bool Sema::AttachTypeConstraint(AutoTypeLoc TL,
1272 NonTypeTemplateParmDecl *NewConstrainedParm,
1273 NonTypeTemplateParmDecl *OrigConstrainedParm,
1274 SourceLocation EllipsisLoc) {
1275 if (NewConstrainedParm->getType() != TL.getType() ||
1276 TL.getAutoKeyword() != AutoTypeKeyword::Auto) {
1277 Diag(NewConstrainedParm->getTypeSourceInfo()->getTypeLoc().getBeginLoc(),
1278 diag::err_unsupported_placeholder_constraint)
1279 << NewConstrainedParm->getTypeSourceInfo()
1280 ->getTypeLoc()
1281 .getSourceRange();
1282 return true;
1284 // FIXME: Concepts: This should be the type of the placeholder, but this is
1285 // unclear in the wording right now.
1286 DeclRefExpr *Ref =
1287 BuildDeclRefExpr(OrigConstrainedParm, OrigConstrainedParm->getType(),
1288 VK_PRValue, OrigConstrainedParm->getLocation());
1289 if (!Ref)
1290 return true;
1291 ExprResult ImmediatelyDeclaredConstraint = formImmediatelyDeclaredConstraint(
1292 *this, TL.getNestedNameSpecifierLoc(), TL.getConceptNameInfo(),
1293 TL.getNamedConcept(), TL.getLAngleLoc(), TL.getRAngleLoc(),
1294 BuildDecltypeType(Ref), OrigConstrainedParm->getLocation(),
1295 [&](TemplateArgumentListInfo &ConstraintArgs) {
1296 for (unsigned I = 0, C = TL.getNumArgs(); I != C; ++I)
1297 ConstraintArgs.addArgument(TL.getArgLoc(I));
1299 EllipsisLoc);
1300 if (ImmediatelyDeclaredConstraint.isInvalid() ||
1301 !ImmediatelyDeclaredConstraint.isUsable())
1302 return true;
1304 NewConstrainedParm->setPlaceholderTypeConstraint(
1305 ImmediatelyDeclaredConstraint.get());
1306 return false;
1309 /// Check that the type of a non-type template parameter is
1310 /// well-formed.
1312 /// \returns the (possibly-promoted) parameter type if valid;
1313 /// otherwise, produces a diagnostic and returns a NULL type.
1314 QualType Sema::CheckNonTypeTemplateParameterType(TypeSourceInfo *&TSI,
1315 SourceLocation Loc) {
1316 if (TSI->getType()->isUndeducedType()) {
1317 // C++17 [temp.dep.expr]p3:
1318 // An id-expression is type-dependent if it contains
1319 // - an identifier associated by name lookup with a non-type
1320 // template-parameter declared with a type that contains a
1321 // placeholder type (7.1.7.4),
1322 TSI = SubstAutoTypeSourceInfoDependent(TSI);
1325 return CheckNonTypeTemplateParameterType(TSI->getType(), Loc);
1328 /// Require the given type to be a structural type, and diagnose if it is not.
1330 /// \return \c true if an error was produced.
1331 bool Sema::RequireStructuralType(QualType T, SourceLocation Loc) {
1332 if (T->isDependentType())
1333 return false;
1335 if (RequireCompleteType(Loc, T, diag::err_template_nontype_parm_incomplete))
1336 return true;
1338 if (T->isStructuralType())
1339 return false;
1341 // Structural types are required to be object types or lvalue references.
1342 if (T->isRValueReferenceType()) {
1343 Diag(Loc, diag::err_template_nontype_parm_rvalue_ref) << T;
1344 return true;
1347 // Don't mention structural types in our diagnostic prior to C++20. Also,
1348 // there's not much more we can say about non-scalar non-class types --
1349 // because we can't see functions or arrays here, those can only be language
1350 // extensions.
1351 if (!getLangOpts().CPlusPlus20 ||
1352 (!T->isScalarType() && !T->isRecordType())) {
1353 Diag(Loc, diag::err_template_nontype_parm_bad_type) << T;
1354 return true;
1357 // Structural types are required to be literal types.
1358 if (RequireLiteralType(Loc, T, diag::err_template_nontype_parm_not_literal))
1359 return true;
1361 Diag(Loc, diag::err_template_nontype_parm_not_structural) << T;
1363 // Drill down into the reason why the class is non-structural.
1364 while (const CXXRecordDecl *RD = T->getAsCXXRecordDecl()) {
1365 // All members are required to be public and non-mutable, and can't be of
1366 // rvalue reference type. Check these conditions first to prefer a "local"
1367 // reason over a more distant one.
1368 for (const FieldDecl *FD : RD->fields()) {
1369 if (FD->getAccess() != AS_public) {
1370 Diag(FD->getLocation(), diag::note_not_structural_non_public) << T << 0;
1371 return true;
1373 if (FD->isMutable()) {
1374 Diag(FD->getLocation(), diag::note_not_structural_mutable_field) << T;
1375 return true;
1377 if (FD->getType()->isRValueReferenceType()) {
1378 Diag(FD->getLocation(), diag::note_not_structural_rvalue_ref_field)
1379 << T;
1380 return true;
1384 // All bases are required to be public.
1385 for (const auto &BaseSpec : RD->bases()) {
1386 if (BaseSpec.getAccessSpecifier() != AS_public) {
1387 Diag(BaseSpec.getBaseTypeLoc(), diag::note_not_structural_non_public)
1388 << T << 1;
1389 return true;
1393 // All subobjects are required to be of structural types.
1394 SourceLocation SubLoc;
1395 QualType SubType;
1396 int Kind = -1;
1398 for (const FieldDecl *FD : RD->fields()) {
1399 QualType T = Context.getBaseElementType(FD->getType());
1400 if (!T->isStructuralType()) {
1401 SubLoc = FD->getLocation();
1402 SubType = T;
1403 Kind = 0;
1404 break;
1408 if (Kind == -1) {
1409 for (const auto &BaseSpec : RD->bases()) {
1410 QualType T = BaseSpec.getType();
1411 if (!T->isStructuralType()) {
1412 SubLoc = BaseSpec.getBaseTypeLoc();
1413 SubType = T;
1414 Kind = 1;
1415 break;
1420 assert(Kind != -1 && "couldn't find reason why type is not structural");
1421 Diag(SubLoc, diag::note_not_structural_subobject)
1422 << T << Kind << SubType;
1423 T = SubType;
1424 RD = T->getAsCXXRecordDecl();
1427 return true;
1430 QualType Sema::CheckNonTypeTemplateParameterType(QualType T,
1431 SourceLocation Loc) {
1432 // We don't allow variably-modified types as the type of non-type template
1433 // parameters.
1434 if (T->isVariablyModifiedType()) {
1435 Diag(Loc, diag::err_variably_modified_nontype_template_param)
1436 << T;
1437 return QualType();
1440 // C++ [temp.param]p4:
1442 // A non-type template-parameter shall have one of the following
1443 // (optionally cv-qualified) types:
1445 // -- integral or enumeration type,
1446 if (T->isIntegralOrEnumerationType() ||
1447 // -- pointer to object or pointer to function,
1448 T->isPointerType() ||
1449 // -- lvalue reference to object or lvalue reference to function,
1450 T->isLValueReferenceType() ||
1451 // -- pointer to member,
1452 T->isMemberPointerType() ||
1453 // -- std::nullptr_t, or
1454 T->isNullPtrType() ||
1455 // -- a type that contains a placeholder type.
1456 T->isUndeducedType()) {
1457 // C++ [temp.param]p5: The top-level cv-qualifiers on the template-parameter
1458 // are ignored when determining its type.
1459 return T.getUnqualifiedType();
1462 // C++ [temp.param]p8:
1464 // A non-type template-parameter of type "array of T" or
1465 // "function returning T" is adjusted to be of type "pointer to
1466 // T" or "pointer to function returning T", respectively.
1467 if (T->isArrayType() || T->isFunctionType())
1468 return Context.getDecayedType(T);
1470 // If T is a dependent type, we can't do the check now, so we
1471 // assume that it is well-formed. Note that stripping off the
1472 // qualifiers here is not really correct if T turns out to be
1473 // an array type, but we'll recompute the type everywhere it's
1474 // used during instantiation, so that should be OK. (Using the
1475 // qualified type is equally wrong.)
1476 if (T->isDependentType())
1477 return T.getUnqualifiedType();
1479 // C++20 [temp.param]p6:
1480 // -- a structural type
1481 if (RequireStructuralType(T, Loc))
1482 return QualType();
1484 if (!getLangOpts().CPlusPlus20) {
1485 // FIXME: Consider allowing structural types as an extension in C++17. (In
1486 // earlier language modes, the template argument evaluation rules are too
1487 // inflexible.)
1488 Diag(Loc, diag::err_template_nontype_parm_bad_structural_type) << T;
1489 return QualType();
1492 Diag(Loc, diag::warn_cxx17_compat_template_nontype_parm_type) << T;
1493 return T.getUnqualifiedType();
1496 NamedDecl *Sema::ActOnNonTypeTemplateParameter(Scope *S, Declarator &D,
1497 unsigned Depth,
1498 unsigned Position,
1499 SourceLocation EqualLoc,
1500 Expr *Default) {
1501 TypeSourceInfo *TInfo = GetTypeForDeclarator(D, S);
1503 // Check that we have valid decl-specifiers specified.
1504 auto CheckValidDeclSpecifiers = [this, &D] {
1505 // C++ [temp.param]
1506 // p1
1507 // template-parameter:
1508 // ...
1509 // parameter-declaration
1510 // p2
1511 // ... A storage class shall not be specified in a template-parameter
1512 // declaration.
1513 // [dcl.typedef]p1:
1514 // The typedef specifier [...] shall not be used in the decl-specifier-seq
1515 // of a parameter-declaration
1516 const DeclSpec &DS = D.getDeclSpec();
1517 auto EmitDiag = [this](SourceLocation Loc) {
1518 Diag(Loc, diag::err_invalid_decl_specifier_in_nontype_parm)
1519 << FixItHint::CreateRemoval(Loc);
1521 if (DS.getStorageClassSpec() != DeclSpec::SCS_unspecified)
1522 EmitDiag(DS.getStorageClassSpecLoc());
1524 if (DS.getThreadStorageClassSpec() != TSCS_unspecified)
1525 EmitDiag(DS.getThreadStorageClassSpecLoc());
1527 // [dcl.inline]p1:
1528 // The inline specifier can be applied only to the declaration or
1529 // definition of a variable or function.
1531 if (DS.isInlineSpecified())
1532 EmitDiag(DS.getInlineSpecLoc());
1534 // [dcl.constexpr]p1:
1535 // The constexpr specifier shall be applied only to the definition of a
1536 // variable or variable template or the declaration of a function or
1537 // function template.
1539 if (DS.hasConstexprSpecifier())
1540 EmitDiag(DS.getConstexprSpecLoc());
1542 // [dcl.fct.spec]p1:
1543 // Function-specifiers can be used only in function declarations.
1545 if (DS.isVirtualSpecified())
1546 EmitDiag(DS.getVirtualSpecLoc());
1548 if (DS.hasExplicitSpecifier())
1549 EmitDiag(DS.getExplicitSpecLoc());
1551 if (DS.isNoreturnSpecified())
1552 EmitDiag(DS.getNoreturnSpecLoc());
1555 CheckValidDeclSpecifiers();
1557 if (const auto *T = TInfo->getType()->getContainedDeducedType())
1558 if (isa<AutoType>(T))
1559 Diag(D.getIdentifierLoc(),
1560 diag::warn_cxx14_compat_template_nontype_parm_auto_type)
1561 << QualType(TInfo->getType()->getContainedAutoType(), 0);
1563 assert(S->isTemplateParamScope() &&
1564 "Non-type template parameter not in template parameter scope!");
1565 bool Invalid = false;
1567 QualType T = CheckNonTypeTemplateParameterType(TInfo, D.getIdentifierLoc());
1568 if (T.isNull()) {
1569 T = Context.IntTy; // Recover with an 'int' type.
1570 Invalid = true;
1573 CheckFunctionOrTemplateParamDeclarator(S, D);
1575 IdentifierInfo *ParamName = D.getIdentifier();
1576 bool IsParameterPack = D.hasEllipsis();
1577 NonTypeTemplateParmDecl *Param = NonTypeTemplateParmDecl::Create(
1578 Context, Context.getTranslationUnitDecl(), D.getBeginLoc(),
1579 D.getIdentifierLoc(), Depth, Position, ParamName, T, IsParameterPack,
1580 TInfo);
1581 Param->setAccess(AS_public);
1583 if (AutoTypeLoc TL = TInfo->getTypeLoc().getContainedAutoTypeLoc())
1584 if (TL.isConstrained())
1585 if (AttachTypeConstraint(TL, Param, Param, D.getEllipsisLoc()))
1586 Invalid = true;
1588 if (Invalid)
1589 Param->setInvalidDecl();
1591 if (Param->isParameterPack())
1592 if (auto *LSI = getEnclosingLambda())
1593 LSI->LocalPacks.push_back(Param);
1595 if (ParamName) {
1596 maybeDiagnoseTemplateParameterShadow(*this, S, D.getIdentifierLoc(),
1597 ParamName);
1599 // Add the template parameter into the current scope.
1600 S->AddDecl(Param);
1601 IdResolver.AddDecl(Param);
1604 // C++0x [temp.param]p9:
1605 // A default template-argument may be specified for any kind of
1606 // template-parameter that is not a template parameter pack.
1607 if (Default && IsParameterPack) {
1608 Diag(EqualLoc, diag::err_template_param_pack_default_arg);
1609 Default = nullptr;
1612 // Check the well-formedness of the default template argument, if provided.
1613 if (Default) {
1614 // Check for unexpanded parameter packs.
1615 if (DiagnoseUnexpandedParameterPack(Default, UPPC_DefaultArgument))
1616 return Param;
1618 Param->setDefaultArgument(Default);
1621 return Param;
1624 /// ActOnTemplateTemplateParameter - Called when a C++ template template
1625 /// parameter (e.g. T in template <template \<typename> class T> class array)
1626 /// has been parsed. S is the current scope.
1627 NamedDecl *Sema::ActOnTemplateTemplateParameter(Scope* S,
1628 SourceLocation TmpLoc,
1629 TemplateParameterList *Params,
1630 SourceLocation EllipsisLoc,
1631 IdentifierInfo *Name,
1632 SourceLocation NameLoc,
1633 unsigned Depth,
1634 unsigned Position,
1635 SourceLocation EqualLoc,
1636 ParsedTemplateArgument Default) {
1637 assert(S->isTemplateParamScope() &&
1638 "Template template parameter not in template parameter scope!");
1640 // Construct the parameter object.
1641 bool IsParameterPack = EllipsisLoc.isValid();
1642 TemplateTemplateParmDecl *Param =
1643 TemplateTemplateParmDecl::Create(Context, Context.getTranslationUnitDecl(),
1644 NameLoc.isInvalid()? TmpLoc : NameLoc,
1645 Depth, Position, IsParameterPack,
1646 Name, Params);
1647 Param->setAccess(AS_public);
1649 if (Param->isParameterPack())
1650 if (auto *LSI = getEnclosingLambda())
1651 LSI->LocalPacks.push_back(Param);
1653 // If the template template parameter has a name, then link the identifier
1654 // into the scope and lookup mechanisms.
1655 if (Name) {
1656 maybeDiagnoseTemplateParameterShadow(*this, S, NameLoc, Name);
1658 S->AddDecl(Param);
1659 IdResolver.AddDecl(Param);
1662 if (Params->size() == 0) {
1663 Diag(Param->getLocation(), diag::err_template_template_parm_no_parms)
1664 << SourceRange(Params->getLAngleLoc(), Params->getRAngleLoc());
1665 Param->setInvalidDecl();
1668 // C++0x [temp.param]p9:
1669 // A default template-argument may be specified for any kind of
1670 // template-parameter that is not a template parameter pack.
1671 if (IsParameterPack && !Default.isInvalid()) {
1672 Diag(EqualLoc, diag::err_template_param_pack_default_arg);
1673 Default = ParsedTemplateArgument();
1676 if (!Default.isInvalid()) {
1677 // Check only that we have a template template argument. We don't want to
1678 // try to check well-formedness now, because our template template parameter
1679 // might have dependent types in its template parameters, which we wouldn't
1680 // be able to match now.
1682 // If none of the template template parameter's template arguments mention
1683 // other template parameters, we could actually perform more checking here.
1684 // However, it isn't worth doing.
1685 TemplateArgumentLoc DefaultArg = translateTemplateArgument(*this, Default);
1686 if (DefaultArg.getArgument().getAsTemplate().isNull()) {
1687 Diag(DefaultArg.getLocation(), diag::err_template_arg_not_valid_template)
1688 << DefaultArg.getSourceRange();
1689 return Param;
1692 // Check for unexpanded parameter packs.
1693 if (DiagnoseUnexpandedParameterPack(DefaultArg.getLocation(),
1694 DefaultArg.getArgument().getAsTemplate(),
1695 UPPC_DefaultArgument))
1696 return Param;
1698 Param->setDefaultArgument(Context, DefaultArg);
1701 return Param;
1704 namespace {
1705 class ConstraintRefersToContainingTemplateChecker
1706 : public TreeTransform<ConstraintRefersToContainingTemplateChecker> {
1707 bool Result = false;
1708 const FunctionDecl *Friend = nullptr;
1709 unsigned TemplateDepth = 0;
1711 // Check a record-decl that we've seen to see if it is a lexical parent of the
1712 // Friend, likely because it was referred to without its template arguments.
1713 void CheckIfContainingRecord(const CXXRecordDecl *CheckingRD) {
1714 CheckingRD = CheckingRD->getMostRecentDecl();
1715 if (!CheckingRD->isTemplated())
1716 return;
1718 for (const DeclContext *DC = Friend->getLexicalDeclContext();
1719 DC && !DC->isFileContext(); DC = DC->getParent())
1720 if (const auto *RD = dyn_cast<CXXRecordDecl>(DC))
1721 if (CheckingRD == RD->getMostRecentDecl())
1722 Result = true;
1725 void CheckNonTypeTemplateParmDecl(NonTypeTemplateParmDecl *D) {
1726 assert(D->getDepth() <= TemplateDepth &&
1727 "Nothing should reference a value below the actual template depth, "
1728 "depth is likely wrong");
1729 if (D->getDepth() != TemplateDepth)
1730 Result = true;
1732 // Necessary because the type of the NTTP might be what refers to the parent
1733 // constriant.
1734 TransformType(D->getType());
1737 public:
1738 using inherited = TreeTransform<ConstraintRefersToContainingTemplateChecker>;
1740 ConstraintRefersToContainingTemplateChecker(Sema &SemaRef,
1741 const FunctionDecl *Friend,
1742 unsigned TemplateDepth)
1743 : inherited(SemaRef), Friend(Friend), TemplateDepth(TemplateDepth) {}
1744 bool getResult() const { return Result; }
1746 // This should be the only template parm type that we have to deal with.
1747 // SubstTempalteTypeParmPack, SubstNonTypeTemplateParmPack, and
1748 // FunctionParmPackExpr are all partially substituted, which cannot happen
1749 // with concepts at this point in translation.
1750 using inherited::TransformTemplateTypeParmType;
1751 QualType TransformTemplateTypeParmType(TypeLocBuilder &TLB,
1752 TemplateTypeParmTypeLoc TL, bool) {
1753 assert(TL.getDecl()->getDepth() <= TemplateDepth &&
1754 "Nothing should reference a value below the actual template depth, "
1755 "depth is likely wrong");
1756 if (TL.getDecl()->getDepth() != TemplateDepth)
1757 Result = true;
1758 return inherited::TransformTemplateTypeParmType(
1759 TLB, TL,
1760 /*SuppressObjCLifetime=*/false);
1763 Decl *TransformDecl(SourceLocation Loc, Decl *D) {
1764 if (!D)
1765 return D;
1766 // FIXME : This is possibly an incomplete list, but it is unclear what other
1767 // Decl kinds could be used to refer to the template parameters. This is a
1768 // best guess so far based on examples currently available, but the
1769 // unreachable should catch future instances/cases.
1770 if (auto *TD = dyn_cast<TypedefNameDecl>(D))
1771 TransformType(TD->getUnderlyingType());
1772 else if (auto *NTTPD = dyn_cast<NonTypeTemplateParmDecl>(D))
1773 CheckNonTypeTemplateParmDecl(NTTPD);
1774 else if (auto *VD = dyn_cast<ValueDecl>(D))
1775 TransformType(VD->getType());
1776 else if (auto *TD = dyn_cast<TemplateDecl>(D))
1777 TransformTemplateParameterList(TD->getTemplateParameters());
1778 else if (auto *RD = dyn_cast<CXXRecordDecl>(D))
1779 CheckIfContainingRecord(RD);
1780 else if (isa<NamedDecl>(D)) {
1781 // No direct types to visit here I believe.
1782 } else
1783 llvm_unreachable("Don't know how to handle this declaration type yet");
1784 return D;
1787 } // namespace
1789 bool Sema::ConstraintExpressionDependsOnEnclosingTemplate(
1790 const FunctionDecl *Friend, unsigned TemplateDepth,
1791 const Expr *Constraint) {
1792 assert(Friend->getFriendObjectKind() && "Only works on a friend");
1793 ConstraintRefersToContainingTemplateChecker Checker(*this, Friend,
1794 TemplateDepth);
1795 Checker.TransformExpr(const_cast<Expr *>(Constraint));
1796 return Checker.getResult();
1799 /// ActOnTemplateParameterList - Builds a TemplateParameterList, optionally
1800 /// constrained by RequiresClause, that contains the template parameters in
1801 /// Params.
1802 TemplateParameterList *
1803 Sema::ActOnTemplateParameterList(unsigned Depth,
1804 SourceLocation ExportLoc,
1805 SourceLocation TemplateLoc,
1806 SourceLocation LAngleLoc,
1807 ArrayRef<NamedDecl *> Params,
1808 SourceLocation RAngleLoc,
1809 Expr *RequiresClause) {
1810 if (ExportLoc.isValid())
1811 Diag(ExportLoc, diag::warn_template_export_unsupported);
1813 for (NamedDecl *P : Params)
1814 warnOnReservedIdentifier(P);
1816 return TemplateParameterList::Create(
1817 Context, TemplateLoc, LAngleLoc,
1818 llvm::ArrayRef(Params.data(), Params.size()), RAngleLoc, RequiresClause);
1821 static void SetNestedNameSpecifier(Sema &S, TagDecl *T,
1822 const CXXScopeSpec &SS) {
1823 if (SS.isSet())
1824 T->setQualifierInfo(SS.getWithLocInContext(S.Context));
1827 // Returns the template parameter list with all default template argument
1828 // information.
1829 static TemplateParameterList *GetTemplateParameterList(TemplateDecl *TD) {
1830 // Make sure we get the template parameter list from the most
1831 // recent declaration, since that is the only one that is guaranteed to
1832 // have all the default template argument information.
1833 return cast<TemplateDecl>(TD->getMostRecentDecl())->getTemplateParameters();
1836 DeclResult Sema::CheckClassTemplate(
1837 Scope *S, unsigned TagSpec, TagUseKind TUK, SourceLocation KWLoc,
1838 CXXScopeSpec &SS, IdentifierInfo *Name, SourceLocation NameLoc,
1839 const ParsedAttributesView &Attr, TemplateParameterList *TemplateParams,
1840 AccessSpecifier AS, SourceLocation ModulePrivateLoc,
1841 SourceLocation FriendLoc, unsigned NumOuterTemplateParamLists,
1842 TemplateParameterList **OuterTemplateParamLists, SkipBodyInfo *SkipBody) {
1843 assert(TemplateParams && TemplateParams->size() > 0 &&
1844 "No template parameters");
1845 assert(TUK != TUK_Reference && "Can only declare or define class templates");
1846 bool Invalid = false;
1848 // Check that we can declare a template here.
1849 if (CheckTemplateDeclScope(S, TemplateParams))
1850 return true;
1852 TagTypeKind Kind = TypeWithKeyword::getTagTypeKindForTypeSpec(TagSpec);
1853 assert(Kind != TagTypeKind::Enum &&
1854 "can't build template of enumerated type");
1856 // There is no such thing as an unnamed class template.
1857 if (!Name) {
1858 Diag(KWLoc, diag::err_template_unnamed_class);
1859 return true;
1862 // Find any previous declaration with this name. For a friend with no
1863 // scope explicitly specified, we only look for tag declarations (per
1864 // C++11 [basic.lookup.elab]p2).
1865 DeclContext *SemanticContext;
1866 LookupResult Previous(*this, Name, NameLoc,
1867 (SS.isEmpty() && TUK == TUK_Friend)
1868 ? LookupTagName : LookupOrdinaryName,
1869 forRedeclarationInCurContext());
1870 if (SS.isNotEmpty() && !SS.isInvalid()) {
1871 SemanticContext = computeDeclContext(SS, true);
1872 if (!SemanticContext) {
1873 // FIXME: Horrible, horrible hack! We can't currently represent this
1874 // in the AST, and historically we have just ignored such friend
1875 // class templates, so don't complain here.
1876 Diag(NameLoc, TUK == TUK_Friend
1877 ? diag::warn_template_qualified_friend_ignored
1878 : diag::err_template_qualified_declarator_no_match)
1879 << SS.getScopeRep() << SS.getRange();
1880 return TUK != TUK_Friend;
1883 if (RequireCompleteDeclContext(SS, SemanticContext))
1884 return true;
1886 // If we're adding a template to a dependent context, we may need to
1887 // rebuilding some of the types used within the template parameter list,
1888 // now that we know what the current instantiation is.
1889 if (SemanticContext->isDependentContext()) {
1890 ContextRAII SavedContext(*this, SemanticContext);
1891 if (RebuildTemplateParamsInCurrentInstantiation(TemplateParams))
1892 Invalid = true;
1893 } else if (TUK != TUK_Friend && TUK != TUK_Reference)
1894 diagnoseQualifiedDeclaration(SS, SemanticContext, Name, NameLoc, false);
1896 LookupQualifiedName(Previous, SemanticContext);
1897 } else {
1898 SemanticContext = CurContext;
1900 // C++14 [class.mem]p14:
1901 // If T is the name of a class, then each of the following shall have a
1902 // name different from T:
1903 // -- every member template of class T
1904 if (TUK != TUK_Friend &&
1905 DiagnoseClassNameShadow(SemanticContext,
1906 DeclarationNameInfo(Name, NameLoc)))
1907 return true;
1909 LookupName(Previous, S);
1912 if (Previous.isAmbiguous())
1913 return true;
1915 NamedDecl *PrevDecl = nullptr;
1916 if (Previous.begin() != Previous.end())
1917 PrevDecl = (*Previous.begin())->getUnderlyingDecl();
1919 if (PrevDecl && PrevDecl->isTemplateParameter()) {
1920 // Maybe we will complain about the shadowed template parameter.
1921 DiagnoseTemplateParameterShadow(NameLoc, PrevDecl);
1922 // Just pretend that we didn't see the previous declaration.
1923 PrevDecl = nullptr;
1926 // If there is a previous declaration with the same name, check
1927 // whether this is a valid redeclaration.
1928 ClassTemplateDecl *PrevClassTemplate =
1929 dyn_cast_or_null<ClassTemplateDecl>(PrevDecl);
1931 // We may have found the injected-class-name of a class template,
1932 // class template partial specialization, or class template specialization.
1933 // In these cases, grab the template that is being defined or specialized.
1934 if (!PrevClassTemplate && PrevDecl && isa<CXXRecordDecl>(PrevDecl) &&
1935 cast<CXXRecordDecl>(PrevDecl)->isInjectedClassName()) {
1936 PrevDecl = cast<CXXRecordDecl>(PrevDecl->getDeclContext());
1937 PrevClassTemplate
1938 = cast<CXXRecordDecl>(PrevDecl)->getDescribedClassTemplate();
1939 if (!PrevClassTemplate && isa<ClassTemplateSpecializationDecl>(PrevDecl)) {
1940 PrevClassTemplate
1941 = cast<ClassTemplateSpecializationDecl>(PrevDecl)
1942 ->getSpecializedTemplate();
1946 if (TUK == TUK_Friend) {
1947 // C++ [namespace.memdef]p3:
1948 // [...] When looking for a prior declaration of a class or a function
1949 // declared as a friend, and when the name of the friend class or
1950 // function is neither a qualified name nor a template-id, scopes outside
1951 // the innermost enclosing namespace scope are not considered.
1952 if (!SS.isSet()) {
1953 DeclContext *OutermostContext = CurContext;
1954 while (!OutermostContext->isFileContext())
1955 OutermostContext = OutermostContext->getLookupParent();
1957 if (PrevDecl &&
1958 (OutermostContext->Equals(PrevDecl->getDeclContext()) ||
1959 OutermostContext->Encloses(PrevDecl->getDeclContext()))) {
1960 SemanticContext = PrevDecl->getDeclContext();
1961 } else {
1962 // Declarations in outer scopes don't matter. However, the outermost
1963 // context we computed is the semantic context for our new
1964 // declaration.
1965 PrevDecl = PrevClassTemplate = nullptr;
1966 SemanticContext = OutermostContext;
1968 // Check that the chosen semantic context doesn't already contain a
1969 // declaration of this name as a non-tag type.
1970 Previous.clear(LookupOrdinaryName);
1971 DeclContext *LookupContext = SemanticContext;
1972 while (LookupContext->isTransparentContext())
1973 LookupContext = LookupContext->getLookupParent();
1974 LookupQualifiedName(Previous, LookupContext);
1976 if (Previous.isAmbiguous())
1977 return true;
1979 if (Previous.begin() != Previous.end())
1980 PrevDecl = (*Previous.begin())->getUnderlyingDecl();
1983 } else if (PrevDecl &&
1984 !isDeclInScope(Previous.getRepresentativeDecl(), SemanticContext,
1985 S, SS.isValid()))
1986 PrevDecl = PrevClassTemplate = nullptr;
1988 if (auto *Shadow = dyn_cast_or_null<UsingShadowDecl>(
1989 PrevDecl ? Previous.getRepresentativeDecl() : nullptr)) {
1990 if (SS.isEmpty() &&
1991 !(PrevClassTemplate &&
1992 PrevClassTemplate->getDeclContext()->getRedeclContext()->Equals(
1993 SemanticContext->getRedeclContext()))) {
1994 Diag(KWLoc, diag::err_using_decl_conflict_reverse);
1995 Diag(Shadow->getTargetDecl()->getLocation(),
1996 diag::note_using_decl_target);
1997 Diag(Shadow->getIntroducer()->getLocation(), diag::note_using_decl) << 0;
1998 // Recover by ignoring the old declaration.
1999 PrevDecl = PrevClassTemplate = nullptr;
2003 if (PrevClassTemplate) {
2004 // Ensure that the template parameter lists are compatible. Skip this check
2005 // for a friend in a dependent context: the template parameter list itself
2006 // could be dependent.
2007 if (!(TUK == TUK_Friend && CurContext->isDependentContext()) &&
2008 !TemplateParameterListsAreEqual(
2009 TemplateCompareNewDeclInfo(SemanticContext ? SemanticContext
2010 : CurContext,
2011 CurContext, KWLoc),
2012 TemplateParams, PrevClassTemplate,
2013 PrevClassTemplate->getTemplateParameters(), /*Complain=*/true,
2014 TPL_TemplateMatch))
2015 return true;
2017 // C++ [temp.class]p4:
2018 // In a redeclaration, partial specialization, explicit
2019 // specialization or explicit instantiation of a class template,
2020 // the class-key shall agree in kind with the original class
2021 // template declaration (7.1.5.3).
2022 RecordDecl *PrevRecordDecl = PrevClassTemplate->getTemplatedDecl();
2023 if (!isAcceptableTagRedeclaration(PrevRecordDecl, Kind,
2024 TUK == TUK_Definition, KWLoc, Name)) {
2025 Diag(KWLoc, diag::err_use_with_wrong_tag)
2026 << Name
2027 << FixItHint::CreateReplacement(KWLoc, PrevRecordDecl->getKindName());
2028 Diag(PrevRecordDecl->getLocation(), diag::note_previous_use);
2029 Kind = PrevRecordDecl->getTagKind();
2032 // Check for redefinition of this class template.
2033 if (TUK == TUK_Definition) {
2034 if (TagDecl *Def = PrevRecordDecl->getDefinition()) {
2035 // If we have a prior definition that is not visible, treat this as
2036 // simply making that previous definition visible.
2037 NamedDecl *Hidden = nullptr;
2038 if (SkipBody && !hasVisibleDefinition(Def, &Hidden)) {
2039 SkipBody->ShouldSkip = true;
2040 SkipBody->Previous = Def;
2041 auto *Tmpl = cast<CXXRecordDecl>(Hidden)->getDescribedClassTemplate();
2042 assert(Tmpl && "original definition of a class template is not a "
2043 "class template?");
2044 makeMergedDefinitionVisible(Hidden);
2045 makeMergedDefinitionVisible(Tmpl);
2046 } else {
2047 Diag(NameLoc, diag::err_redefinition) << Name;
2048 Diag(Def->getLocation(), diag::note_previous_definition);
2049 // FIXME: Would it make sense to try to "forget" the previous
2050 // definition, as part of error recovery?
2051 return true;
2055 } else if (PrevDecl) {
2056 // C++ [temp]p5:
2057 // A class template shall not have the same name as any other
2058 // template, class, function, object, enumeration, enumerator,
2059 // namespace, or type in the same scope (3.3), except as specified
2060 // in (14.5.4).
2061 Diag(NameLoc, diag::err_redefinition_different_kind) << Name;
2062 Diag(PrevDecl->getLocation(), diag::note_previous_definition);
2063 return true;
2066 // Check the template parameter list of this declaration, possibly
2067 // merging in the template parameter list from the previous class
2068 // template declaration. Skip this check for a friend in a dependent
2069 // context, because the template parameter list might be dependent.
2070 if (!(TUK == TUK_Friend && CurContext->isDependentContext()) &&
2071 CheckTemplateParameterList(
2072 TemplateParams,
2073 PrevClassTemplate ? GetTemplateParameterList(PrevClassTemplate)
2074 : nullptr,
2075 (SS.isSet() && SemanticContext && SemanticContext->isRecord() &&
2076 SemanticContext->isDependentContext())
2077 ? TPC_ClassTemplateMember
2078 : TUK == TUK_Friend ? TPC_FriendClassTemplate
2079 : TPC_ClassTemplate,
2080 SkipBody))
2081 Invalid = true;
2083 if (SS.isSet()) {
2084 // If the name of the template was qualified, we must be defining the
2085 // template out-of-line.
2086 if (!SS.isInvalid() && !Invalid && !PrevClassTemplate) {
2087 Diag(NameLoc, TUK == TUK_Friend ? diag::err_friend_decl_does_not_match
2088 : diag::err_member_decl_does_not_match)
2089 << Name << SemanticContext << /*IsDefinition*/true << SS.getRange();
2090 Invalid = true;
2094 // If this is a templated friend in a dependent context we should not put it
2095 // on the redecl chain. In some cases, the templated friend can be the most
2096 // recent declaration tricking the template instantiator to make substitutions
2097 // there.
2098 // FIXME: Figure out how to combine with shouldLinkDependentDeclWithPrevious
2099 bool ShouldAddRedecl
2100 = !(TUK == TUK_Friend && CurContext->isDependentContext());
2102 CXXRecordDecl *NewClass =
2103 CXXRecordDecl::Create(Context, Kind, SemanticContext, KWLoc, NameLoc, Name,
2104 PrevClassTemplate && ShouldAddRedecl ?
2105 PrevClassTemplate->getTemplatedDecl() : nullptr,
2106 /*DelayTypeCreation=*/true);
2107 SetNestedNameSpecifier(*this, NewClass, SS);
2108 if (NumOuterTemplateParamLists > 0)
2109 NewClass->setTemplateParameterListsInfo(
2110 Context,
2111 llvm::ArrayRef(OuterTemplateParamLists, NumOuterTemplateParamLists));
2113 // Add alignment attributes if necessary; these attributes are checked when
2114 // the ASTContext lays out the structure.
2115 if (TUK == TUK_Definition && (!SkipBody || !SkipBody->ShouldSkip)) {
2116 AddAlignmentAttributesForRecord(NewClass);
2117 AddMsStructLayoutForRecord(NewClass);
2120 ClassTemplateDecl *NewTemplate
2121 = ClassTemplateDecl::Create(Context, SemanticContext, NameLoc,
2122 DeclarationName(Name), TemplateParams,
2123 NewClass);
2125 if (ShouldAddRedecl)
2126 NewTemplate->setPreviousDecl(PrevClassTemplate);
2128 NewClass->setDescribedClassTemplate(NewTemplate);
2130 if (ModulePrivateLoc.isValid())
2131 NewTemplate->setModulePrivate();
2133 // Build the type for the class template declaration now.
2134 QualType T = NewTemplate->getInjectedClassNameSpecialization();
2135 T = Context.getInjectedClassNameType(NewClass, T);
2136 assert(T->isDependentType() && "Class template type is not dependent?");
2137 (void)T;
2139 // If we are providing an explicit specialization of a member that is a
2140 // class template, make a note of that.
2141 if (PrevClassTemplate &&
2142 PrevClassTemplate->getInstantiatedFromMemberTemplate())
2143 PrevClassTemplate->setMemberSpecialization();
2145 // Set the access specifier.
2146 if (!Invalid && TUK != TUK_Friend && NewTemplate->getDeclContext()->isRecord())
2147 SetMemberAccessSpecifier(NewTemplate, PrevClassTemplate, AS);
2149 // Set the lexical context of these templates
2150 NewClass->setLexicalDeclContext(CurContext);
2151 NewTemplate->setLexicalDeclContext(CurContext);
2153 if (TUK == TUK_Definition && (!SkipBody || !SkipBody->ShouldSkip))
2154 NewClass->startDefinition();
2156 ProcessDeclAttributeList(S, NewClass, Attr);
2158 if (PrevClassTemplate)
2159 mergeDeclAttributes(NewClass, PrevClassTemplate->getTemplatedDecl());
2161 AddPushedVisibilityAttribute(NewClass);
2162 inferGslOwnerPointerAttribute(NewClass);
2164 if (TUK != TUK_Friend) {
2165 // Per C++ [basic.scope.temp]p2, skip the template parameter scopes.
2166 Scope *Outer = S;
2167 while ((Outer->getFlags() & Scope::TemplateParamScope) != 0)
2168 Outer = Outer->getParent();
2169 PushOnScopeChains(NewTemplate, Outer);
2170 } else {
2171 if (PrevClassTemplate && PrevClassTemplate->getAccess() != AS_none) {
2172 NewTemplate->setAccess(PrevClassTemplate->getAccess());
2173 NewClass->setAccess(PrevClassTemplate->getAccess());
2176 NewTemplate->setObjectOfFriendDecl();
2178 // Friend templates are visible in fairly strange ways.
2179 if (!CurContext->isDependentContext()) {
2180 DeclContext *DC = SemanticContext->getRedeclContext();
2181 DC->makeDeclVisibleInContext(NewTemplate);
2182 if (Scope *EnclosingScope = getScopeForDeclContext(S, DC))
2183 PushOnScopeChains(NewTemplate, EnclosingScope,
2184 /* AddToContext = */ false);
2187 FriendDecl *Friend = FriendDecl::Create(
2188 Context, CurContext, NewClass->getLocation(), NewTemplate, FriendLoc);
2189 Friend->setAccess(AS_public);
2190 CurContext->addDecl(Friend);
2193 if (PrevClassTemplate)
2194 CheckRedeclarationInModule(NewTemplate, PrevClassTemplate);
2196 if (Invalid) {
2197 NewTemplate->setInvalidDecl();
2198 NewClass->setInvalidDecl();
2201 ActOnDocumentableDecl(NewTemplate);
2203 if (SkipBody && SkipBody->ShouldSkip)
2204 return SkipBody->Previous;
2206 return NewTemplate;
2209 namespace {
2210 /// Tree transform to "extract" a transformed type from a class template's
2211 /// constructor to a deduction guide.
2212 class ExtractTypeForDeductionGuide
2213 : public TreeTransform<ExtractTypeForDeductionGuide> {
2214 llvm::SmallVectorImpl<TypedefNameDecl *> &MaterializedTypedefs;
2216 public:
2217 typedef TreeTransform<ExtractTypeForDeductionGuide> Base;
2218 ExtractTypeForDeductionGuide(
2219 Sema &SemaRef,
2220 llvm::SmallVectorImpl<TypedefNameDecl *> &MaterializedTypedefs)
2221 : Base(SemaRef), MaterializedTypedefs(MaterializedTypedefs) {}
2223 TypeSourceInfo *transform(TypeSourceInfo *TSI) { return TransformType(TSI); }
2225 QualType TransformTypedefType(TypeLocBuilder &TLB, TypedefTypeLoc TL) {
2226 ASTContext &Context = SemaRef.getASTContext();
2227 TypedefNameDecl *OrigDecl = TL.getTypedefNameDecl();
2228 TypedefNameDecl *Decl = OrigDecl;
2229 // Transform the underlying type of the typedef and clone the Decl only if
2230 // the typedef has a dependent context.
2231 if (OrigDecl->getDeclContext()->isDependentContext()) {
2232 TypeLocBuilder InnerTLB;
2233 QualType Transformed =
2234 TransformType(InnerTLB, OrigDecl->getTypeSourceInfo()->getTypeLoc());
2235 TypeSourceInfo *TSI = InnerTLB.getTypeSourceInfo(Context, Transformed);
2236 if (isa<TypeAliasDecl>(OrigDecl))
2237 Decl = TypeAliasDecl::Create(
2238 Context, Context.getTranslationUnitDecl(), OrigDecl->getBeginLoc(),
2239 OrigDecl->getLocation(), OrigDecl->getIdentifier(), TSI);
2240 else {
2241 assert(isa<TypedefDecl>(OrigDecl) && "Not a Type alias or typedef");
2242 Decl = TypedefDecl::Create(
2243 Context, Context.getTranslationUnitDecl(), OrigDecl->getBeginLoc(),
2244 OrigDecl->getLocation(), OrigDecl->getIdentifier(), TSI);
2246 MaterializedTypedefs.push_back(Decl);
2249 QualType TDTy = Context.getTypedefType(Decl);
2250 TypedefTypeLoc TypedefTL = TLB.push<TypedefTypeLoc>(TDTy);
2251 TypedefTL.setNameLoc(TL.getNameLoc());
2253 return TDTy;
2257 /// Transform to convert portions of a constructor declaration into the
2258 /// corresponding deduction guide, per C++1z [over.match.class.deduct]p1.
2259 struct ConvertConstructorToDeductionGuideTransform {
2260 ConvertConstructorToDeductionGuideTransform(Sema &S,
2261 ClassTemplateDecl *Template)
2262 : SemaRef(S), Template(Template) {
2263 // If the template is nested, then we need to use the original
2264 // pattern to iterate over the constructors.
2265 ClassTemplateDecl *Pattern = Template;
2266 while (Pattern->getInstantiatedFromMemberTemplate()) {
2267 if (Pattern->isMemberSpecialization())
2268 break;
2269 Pattern = Pattern->getInstantiatedFromMemberTemplate();
2270 NestedPattern = Pattern;
2273 if (NestedPattern)
2274 OuterInstantiationArgs = SemaRef.getTemplateInstantiationArgs(Template);
2277 Sema &SemaRef;
2278 ClassTemplateDecl *Template;
2279 ClassTemplateDecl *NestedPattern = nullptr;
2281 DeclContext *DC = Template->getDeclContext();
2282 CXXRecordDecl *Primary = Template->getTemplatedDecl();
2283 DeclarationName DeductionGuideName =
2284 SemaRef.Context.DeclarationNames.getCXXDeductionGuideName(Template);
2286 QualType DeducedType = SemaRef.Context.getTypeDeclType(Primary);
2288 // Index adjustment to apply to convert depth-1 template parameters into
2289 // depth-0 template parameters.
2290 unsigned Depth1IndexAdjustment = Template->getTemplateParameters()->size();
2292 // Instantiation arguments for the outermost depth-1 templates
2293 // when the template is nested
2294 MultiLevelTemplateArgumentList OuterInstantiationArgs;
2296 /// Transform a constructor declaration into a deduction guide.
2297 NamedDecl *transformConstructor(FunctionTemplateDecl *FTD,
2298 CXXConstructorDecl *CD) {
2299 SmallVector<TemplateArgument, 16> SubstArgs;
2301 LocalInstantiationScope Scope(SemaRef);
2303 // C++ [over.match.class.deduct]p1:
2304 // -- For each constructor of the class template designated by the
2305 // template-name, a function template with the following properties:
2307 // -- The template parameters are the template parameters of the class
2308 // template followed by the template parameters (including default
2309 // template arguments) of the constructor, if any.
2310 TemplateParameterList *TemplateParams = GetTemplateParameterList(Template);
2311 if (FTD) {
2312 TemplateParameterList *InnerParams = FTD->getTemplateParameters();
2313 SmallVector<NamedDecl *, 16> AllParams;
2314 SmallVector<TemplateArgument, 16> Depth1Args;
2315 AllParams.reserve(TemplateParams->size() + InnerParams->size());
2316 AllParams.insert(AllParams.begin(),
2317 TemplateParams->begin(), TemplateParams->end());
2318 SubstArgs.reserve(InnerParams->size());
2319 Depth1Args.reserve(InnerParams->size());
2321 // Later template parameters could refer to earlier ones, so build up
2322 // a list of substituted template arguments as we go.
2323 for (NamedDecl *Param : *InnerParams) {
2324 MultiLevelTemplateArgumentList Args;
2325 Args.setKind(TemplateSubstitutionKind::Rewrite);
2326 Args.addOuterTemplateArguments(Depth1Args);
2327 Args.addOuterRetainedLevel();
2328 if (NestedPattern)
2329 Args.addOuterRetainedLevels(NestedPattern->getTemplateDepth());
2330 NamedDecl *NewParam = transformTemplateParameter(Param, Args);
2331 if (!NewParam)
2332 return nullptr;
2334 // Constraints require that we substitute depth-1 arguments
2335 // to match depths when substituted for evaluation later
2336 Depth1Args.push_back(SemaRef.Context.getCanonicalTemplateArgument(
2337 SemaRef.Context.getInjectedTemplateArg(NewParam)));
2339 if (NestedPattern) {
2340 TemplateDeclInstantiator Instantiator(SemaRef, DC,
2341 OuterInstantiationArgs);
2342 Instantiator.setEvaluateConstraints(false);
2343 SemaRef.runWithSufficientStackSpace(NewParam->getLocation(), [&] {
2344 NewParam = cast<NamedDecl>(Instantiator.Visit(NewParam));
2348 assert(NewParam->getTemplateDepth() == 0 &&
2349 "Unexpected template parameter depth");
2351 AllParams.push_back(NewParam);
2352 SubstArgs.push_back(SemaRef.Context.getCanonicalTemplateArgument(
2353 SemaRef.Context.getInjectedTemplateArg(NewParam)));
2356 // Substitute new template parameters into requires-clause if present.
2357 Expr *RequiresClause = nullptr;
2358 if (Expr *InnerRC = InnerParams->getRequiresClause()) {
2359 MultiLevelTemplateArgumentList Args;
2360 Args.setKind(TemplateSubstitutionKind::Rewrite);
2361 Args.addOuterTemplateArguments(Depth1Args);
2362 Args.addOuterRetainedLevel();
2363 if (NestedPattern)
2364 Args.addOuterRetainedLevels(NestedPattern->getTemplateDepth());
2365 ExprResult E = SemaRef.SubstExpr(InnerRC, Args);
2366 if (E.isInvalid())
2367 return nullptr;
2368 RequiresClause = E.getAs<Expr>();
2371 TemplateParams = TemplateParameterList::Create(
2372 SemaRef.Context, InnerParams->getTemplateLoc(),
2373 InnerParams->getLAngleLoc(), AllParams, InnerParams->getRAngleLoc(),
2374 RequiresClause);
2377 // If we built a new template-parameter-list, track that we need to
2378 // substitute references to the old parameters into references to the
2379 // new ones.
2380 MultiLevelTemplateArgumentList Args;
2381 Args.setKind(TemplateSubstitutionKind::Rewrite);
2382 if (FTD) {
2383 Args.addOuterTemplateArguments(SubstArgs);
2384 Args.addOuterRetainedLevel();
2387 if (NestedPattern)
2388 Args.addOuterRetainedLevels(NestedPattern->getTemplateDepth());
2390 FunctionProtoTypeLoc FPTL = CD->getTypeSourceInfo()->getTypeLoc()
2391 .getAsAdjusted<FunctionProtoTypeLoc>();
2392 assert(FPTL && "no prototype for constructor declaration");
2394 // Transform the type of the function, adjusting the return type and
2395 // replacing references to the old parameters with references to the
2396 // new ones.
2397 TypeLocBuilder TLB;
2398 SmallVector<ParmVarDecl*, 8> Params;
2399 SmallVector<TypedefNameDecl *, 4> MaterializedTypedefs;
2400 QualType NewType = transformFunctionProtoType(TLB, FPTL, Params, Args,
2401 MaterializedTypedefs);
2402 if (NewType.isNull())
2403 return nullptr;
2404 TypeSourceInfo *NewTInfo = TLB.getTypeSourceInfo(SemaRef.Context, NewType);
2406 return buildDeductionGuide(TemplateParams, CD, CD->getExplicitSpecifier(),
2407 NewTInfo, CD->getBeginLoc(), CD->getLocation(),
2408 CD->getEndLoc(), MaterializedTypedefs);
2411 /// Build a deduction guide with the specified parameter types.
2412 NamedDecl *buildSimpleDeductionGuide(MutableArrayRef<QualType> ParamTypes) {
2413 SourceLocation Loc = Template->getLocation();
2415 // Build the requested type.
2416 FunctionProtoType::ExtProtoInfo EPI;
2417 EPI.HasTrailingReturn = true;
2418 QualType Result = SemaRef.BuildFunctionType(DeducedType, ParamTypes, Loc,
2419 DeductionGuideName, EPI);
2420 TypeSourceInfo *TSI = SemaRef.Context.getTrivialTypeSourceInfo(Result, Loc);
2422 FunctionProtoTypeLoc FPTL =
2423 TSI->getTypeLoc().castAs<FunctionProtoTypeLoc>();
2425 // Build the parameters, needed during deduction / substitution.
2426 SmallVector<ParmVarDecl*, 4> Params;
2427 for (auto T : ParamTypes) {
2428 ParmVarDecl *NewParam = ParmVarDecl::Create(
2429 SemaRef.Context, DC, Loc, Loc, nullptr, T,
2430 SemaRef.Context.getTrivialTypeSourceInfo(T, Loc), SC_None, nullptr);
2431 NewParam->setScopeInfo(0, Params.size());
2432 FPTL.setParam(Params.size(), NewParam);
2433 Params.push_back(NewParam);
2436 return buildDeductionGuide(GetTemplateParameterList(Template), nullptr,
2437 ExplicitSpecifier(), TSI, Loc, Loc, Loc);
2440 private:
2441 /// Transform a constructor template parameter into a deduction guide template
2442 /// parameter, rebuilding any internal references to earlier parameters and
2443 /// renumbering as we go.
2444 NamedDecl *transformTemplateParameter(NamedDecl *TemplateParam,
2445 MultiLevelTemplateArgumentList &Args) {
2446 if (auto *TTP = dyn_cast<TemplateTypeParmDecl>(TemplateParam)) {
2447 // TemplateTypeParmDecl's index cannot be changed after creation, so
2448 // substitute it directly.
2449 auto *NewTTP = TemplateTypeParmDecl::Create(
2450 SemaRef.Context, DC, TTP->getBeginLoc(), TTP->getLocation(),
2451 TTP->getDepth() - 1, Depth1IndexAdjustment + TTP->getIndex(),
2452 TTP->getIdentifier(), TTP->wasDeclaredWithTypename(),
2453 TTP->isParameterPack(), TTP->hasTypeConstraint(),
2454 TTP->isExpandedParameterPack()
2455 ? std::optional<unsigned>(TTP->getNumExpansionParameters())
2456 : std::nullopt);
2457 if (const auto *TC = TTP->getTypeConstraint())
2458 SemaRef.SubstTypeConstraint(NewTTP, TC, Args,
2459 /*EvaluateConstraint*/ true);
2460 if (TTP->hasDefaultArgument()) {
2461 TypeSourceInfo *InstantiatedDefaultArg =
2462 SemaRef.SubstType(TTP->getDefaultArgumentInfo(), Args,
2463 TTP->getDefaultArgumentLoc(), TTP->getDeclName());
2464 if (InstantiatedDefaultArg)
2465 NewTTP->setDefaultArgument(InstantiatedDefaultArg);
2467 SemaRef.CurrentInstantiationScope->InstantiatedLocal(TemplateParam,
2468 NewTTP);
2469 return NewTTP;
2472 if (auto *TTP = dyn_cast<TemplateTemplateParmDecl>(TemplateParam))
2473 return transformTemplateParameterImpl(TTP, Args);
2475 return transformTemplateParameterImpl(
2476 cast<NonTypeTemplateParmDecl>(TemplateParam), Args);
2478 template<typename TemplateParmDecl>
2479 TemplateParmDecl *
2480 transformTemplateParameterImpl(TemplateParmDecl *OldParam,
2481 MultiLevelTemplateArgumentList &Args) {
2482 // Ask the template instantiator to do the heavy lifting for us, then adjust
2483 // the index of the parameter once it's done.
2484 auto *NewParam =
2485 cast<TemplateParmDecl>(SemaRef.SubstDecl(OldParam, DC, Args));
2486 assert(NewParam->getDepth() == OldParam->getDepth() - 1 &&
2487 "unexpected template param depth");
2488 NewParam->setPosition(NewParam->getPosition() + Depth1IndexAdjustment);
2489 return NewParam;
2492 QualType transformFunctionProtoType(
2493 TypeLocBuilder &TLB, FunctionProtoTypeLoc TL,
2494 SmallVectorImpl<ParmVarDecl *> &Params,
2495 MultiLevelTemplateArgumentList &Args,
2496 SmallVectorImpl<TypedefNameDecl *> &MaterializedTypedefs) {
2497 SmallVector<QualType, 4> ParamTypes;
2498 const FunctionProtoType *T = TL.getTypePtr();
2500 // -- The types of the function parameters are those of the constructor.
2501 for (auto *OldParam : TL.getParams()) {
2502 ParmVarDecl *NewParam =
2503 transformFunctionTypeParam(OldParam, Args, MaterializedTypedefs);
2504 if (NestedPattern && NewParam)
2505 NewParam = transformFunctionTypeParam(NewParam, OuterInstantiationArgs,
2506 MaterializedTypedefs);
2507 if (!NewParam)
2508 return QualType();
2509 ParamTypes.push_back(NewParam->getType());
2510 Params.push_back(NewParam);
2513 // -- The return type is the class template specialization designated by
2514 // the template-name and template arguments corresponding to the
2515 // template parameters obtained from the class template.
2517 // We use the injected-class-name type of the primary template instead.
2518 // This has the convenient property that it is different from any type that
2519 // the user can write in a deduction-guide (because they cannot enter the
2520 // context of the template), so implicit deduction guides can never collide
2521 // with explicit ones.
2522 QualType ReturnType = DeducedType;
2523 TLB.pushTypeSpec(ReturnType).setNameLoc(Primary->getLocation());
2525 // Resolving a wording defect, we also inherit the variadicness of the
2526 // constructor.
2527 FunctionProtoType::ExtProtoInfo EPI;
2528 EPI.Variadic = T->isVariadic();
2529 EPI.HasTrailingReturn = true;
2531 QualType Result = SemaRef.BuildFunctionType(
2532 ReturnType, ParamTypes, TL.getBeginLoc(), DeductionGuideName, EPI);
2533 if (Result.isNull())
2534 return QualType();
2536 FunctionProtoTypeLoc NewTL = TLB.push<FunctionProtoTypeLoc>(Result);
2537 NewTL.setLocalRangeBegin(TL.getLocalRangeBegin());
2538 NewTL.setLParenLoc(TL.getLParenLoc());
2539 NewTL.setRParenLoc(TL.getRParenLoc());
2540 NewTL.setExceptionSpecRange(SourceRange());
2541 NewTL.setLocalRangeEnd(TL.getLocalRangeEnd());
2542 for (unsigned I = 0, E = NewTL.getNumParams(); I != E; ++I)
2543 NewTL.setParam(I, Params[I]);
2545 return Result;
2548 ParmVarDecl *transformFunctionTypeParam(
2549 ParmVarDecl *OldParam, MultiLevelTemplateArgumentList &Args,
2550 llvm::SmallVectorImpl<TypedefNameDecl *> &MaterializedTypedefs) {
2551 TypeSourceInfo *OldDI = OldParam->getTypeSourceInfo();
2552 TypeSourceInfo *NewDI;
2553 if (auto PackTL = OldDI->getTypeLoc().getAs<PackExpansionTypeLoc>()) {
2554 // Expand out the one and only element in each inner pack.
2555 Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, 0);
2556 NewDI =
2557 SemaRef.SubstType(PackTL.getPatternLoc(), Args,
2558 OldParam->getLocation(), OldParam->getDeclName());
2559 if (!NewDI) return nullptr;
2560 NewDI =
2561 SemaRef.CheckPackExpansion(NewDI, PackTL.getEllipsisLoc(),
2562 PackTL.getTypePtr()->getNumExpansions());
2563 } else
2564 NewDI = SemaRef.SubstType(OldDI, Args, OldParam->getLocation(),
2565 OldParam->getDeclName());
2566 if (!NewDI)
2567 return nullptr;
2569 // Extract the type. This (for instance) replaces references to typedef
2570 // members of the current instantiations with the definitions of those
2571 // typedefs, avoiding triggering instantiation of the deduced type during
2572 // deduction.
2573 NewDI = ExtractTypeForDeductionGuide(SemaRef, MaterializedTypedefs)
2574 .transform(NewDI);
2576 // Resolving a wording defect, we also inherit default arguments from the
2577 // constructor.
2578 ExprResult NewDefArg;
2579 if (OldParam->hasDefaultArg()) {
2580 // We don't care what the value is (we won't use it); just create a
2581 // placeholder to indicate there is a default argument.
2582 QualType ParamTy = NewDI->getType();
2583 NewDefArg = new (SemaRef.Context)
2584 OpaqueValueExpr(OldParam->getDefaultArg()->getBeginLoc(),
2585 ParamTy.getNonLValueExprType(SemaRef.Context),
2586 ParamTy->isLValueReferenceType() ? VK_LValue
2587 : ParamTy->isRValueReferenceType() ? VK_XValue
2588 : VK_PRValue);
2591 ParmVarDecl *NewParam = ParmVarDecl::Create(SemaRef.Context, DC,
2592 OldParam->getInnerLocStart(),
2593 OldParam->getLocation(),
2594 OldParam->getIdentifier(),
2595 NewDI->getType(),
2596 NewDI,
2597 OldParam->getStorageClass(),
2598 NewDefArg.get());
2599 NewParam->setScopeInfo(OldParam->getFunctionScopeDepth(),
2600 OldParam->getFunctionScopeIndex());
2601 SemaRef.CurrentInstantiationScope->InstantiatedLocal(OldParam, NewParam);
2602 return NewParam;
2605 FunctionTemplateDecl *buildDeductionGuide(
2606 TemplateParameterList *TemplateParams, CXXConstructorDecl *Ctor,
2607 ExplicitSpecifier ES, TypeSourceInfo *TInfo, SourceLocation LocStart,
2608 SourceLocation Loc, SourceLocation LocEnd,
2609 llvm::ArrayRef<TypedefNameDecl *> MaterializedTypedefs = {}) {
2610 DeclarationNameInfo Name(DeductionGuideName, Loc);
2611 ArrayRef<ParmVarDecl *> Params =
2612 TInfo->getTypeLoc().castAs<FunctionProtoTypeLoc>().getParams();
2614 // Build the implicit deduction guide template.
2615 auto *Guide =
2616 CXXDeductionGuideDecl::Create(SemaRef.Context, DC, LocStart, ES, Name,
2617 TInfo->getType(), TInfo, LocEnd, Ctor);
2618 Guide->setImplicit();
2619 Guide->setParams(Params);
2621 for (auto *Param : Params)
2622 Param->setDeclContext(Guide);
2623 for (auto *TD : MaterializedTypedefs)
2624 TD->setDeclContext(Guide);
2626 auto *GuideTemplate = FunctionTemplateDecl::Create(
2627 SemaRef.Context, DC, Loc, DeductionGuideName, TemplateParams, Guide);
2628 GuideTemplate->setImplicit();
2629 Guide->setDescribedFunctionTemplate(GuideTemplate);
2631 if (isa<CXXRecordDecl>(DC)) {
2632 Guide->setAccess(AS_public);
2633 GuideTemplate->setAccess(AS_public);
2636 DC->addDecl(GuideTemplate);
2637 return GuideTemplate;
2642 FunctionTemplateDecl *Sema::DeclareImplicitDeductionGuideFromInitList(
2643 TemplateDecl *Template, MutableArrayRef<QualType> ParamTypes,
2644 SourceLocation Loc) {
2645 if (CXXRecordDecl *DefRecord =
2646 cast<CXXRecordDecl>(Template->getTemplatedDecl())->getDefinition()) {
2647 if (TemplateDecl *DescribedTemplate =
2648 DefRecord->getDescribedClassTemplate())
2649 Template = DescribedTemplate;
2652 DeclContext *DC = Template->getDeclContext();
2653 if (DC->isDependentContext())
2654 return nullptr;
2656 ConvertConstructorToDeductionGuideTransform Transform(
2657 *this, cast<ClassTemplateDecl>(Template));
2658 if (!isCompleteType(Loc, Transform.DeducedType))
2659 return nullptr;
2661 // In case we were expanding a pack when we attempted to declare deduction
2662 // guides, turn off pack expansion for everything we're about to do.
2663 ArgumentPackSubstitutionIndexRAII SubstIndex(*this,
2664 /*NewSubstitutionIndex=*/-1);
2665 // Create a template instantiation record to track the "instantiation" of
2666 // constructors into deduction guides.
2667 InstantiatingTemplate BuildingDeductionGuides(
2668 *this, Loc, Template,
2669 Sema::InstantiatingTemplate::BuildingDeductionGuidesTag{});
2670 if (BuildingDeductionGuides.isInvalid())
2671 return nullptr;
2673 return cast<FunctionTemplateDecl>(
2674 Transform.buildSimpleDeductionGuide(ParamTypes));
2677 void Sema::DeclareImplicitDeductionGuides(TemplateDecl *Template,
2678 SourceLocation Loc) {
2679 if (CXXRecordDecl *DefRecord =
2680 cast<CXXRecordDecl>(Template->getTemplatedDecl())->getDefinition()) {
2681 if (TemplateDecl *DescribedTemplate = DefRecord->getDescribedClassTemplate())
2682 Template = DescribedTemplate;
2685 DeclContext *DC = Template->getDeclContext();
2686 if (DC->isDependentContext())
2687 return;
2689 ConvertConstructorToDeductionGuideTransform Transform(
2690 *this, cast<ClassTemplateDecl>(Template));
2691 if (!isCompleteType(Loc, Transform.DeducedType))
2692 return;
2694 // Check whether we've already declared deduction guides for this template.
2695 // FIXME: Consider storing a flag on the template to indicate this.
2696 auto Existing = DC->lookup(Transform.DeductionGuideName);
2697 for (auto *D : Existing)
2698 if (D->isImplicit())
2699 return;
2701 // In case we were expanding a pack when we attempted to declare deduction
2702 // guides, turn off pack expansion for everything we're about to do.
2703 ArgumentPackSubstitutionIndexRAII SubstIndex(*this, -1);
2704 // Create a template instantiation record to track the "instantiation" of
2705 // constructors into deduction guides.
2706 InstantiatingTemplate BuildingDeductionGuides(
2707 *this, Loc, Template,
2708 Sema::InstantiatingTemplate::BuildingDeductionGuidesTag{});
2709 if (BuildingDeductionGuides.isInvalid())
2710 return;
2712 // Convert declared constructors into deduction guide templates.
2713 // FIXME: Skip constructors for which deduction must necessarily fail (those
2714 // for which some class template parameter without a default argument never
2715 // appears in a deduced context).
2716 ClassTemplateDecl *Pattern =
2717 Transform.NestedPattern ? Transform.NestedPattern : Transform.Template;
2718 ContextRAII SavedContext(*this, Pattern->getTemplatedDecl());
2719 llvm::SmallPtrSet<NamedDecl *, 8> ProcessedCtors;
2720 bool AddedAny = false;
2721 for (NamedDecl *D : LookupConstructors(Pattern->getTemplatedDecl())) {
2722 D = D->getUnderlyingDecl();
2723 if (D->isInvalidDecl() || D->isImplicit())
2724 continue;
2726 D = cast<NamedDecl>(D->getCanonicalDecl());
2728 // Within C++20 modules, we may have multiple same constructors in
2729 // multiple same RecordDecls. And it doesn't make sense to create
2730 // duplicated deduction guides for the duplicated constructors.
2731 if (ProcessedCtors.count(D))
2732 continue;
2734 auto *FTD = dyn_cast<FunctionTemplateDecl>(D);
2735 auto *CD =
2736 dyn_cast_or_null<CXXConstructorDecl>(FTD ? FTD->getTemplatedDecl() : D);
2737 // Class-scope explicit specializations (MS extension) do not result in
2738 // deduction guides.
2739 if (!CD || (!FTD && CD->isFunctionTemplateSpecialization()))
2740 continue;
2742 // Cannot make a deduction guide when unparsed arguments are present.
2743 if (llvm::any_of(CD->parameters(), [](ParmVarDecl *P) {
2744 return !P || P->hasUnparsedDefaultArg();
2746 continue;
2748 ProcessedCtors.insert(D);
2749 Transform.transformConstructor(FTD, CD);
2750 AddedAny = true;
2753 // C++17 [over.match.class.deduct]
2754 // -- If C is not defined or does not declare any constructors, an
2755 // additional function template derived as above from a hypothetical
2756 // constructor C().
2757 if (!AddedAny)
2758 Transform.buildSimpleDeductionGuide(std::nullopt);
2760 // -- An additional function template derived as above from a hypothetical
2761 // constructor C(C), called the copy deduction candidate.
2762 cast<CXXDeductionGuideDecl>(
2763 cast<FunctionTemplateDecl>(
2764 Transform.buildSimpleDeductionGuide(Transform.DeducedType))
2765 ->getTemplatedDecl())
2766 ->setDeductionCandidateKind(DeductionCandidate::Copy);
2768 SavedContext.pop();
2771 /// Diagnose the presence of a default template argument on a
2772 /// template parameter, which is ill-formed in certain contexts.
2774 /// \returns true if the default template argument should be dropped.
2775 static bool DiagnoseDefaultTemplateArgument(Sema &S,
2776 Sema::TemplateParamListContext TPC,
2777 SourceLocation ParamLoc,
2778 SourceRange DefArgRange) {
2779 switch (TPC) {
2780 case Sema::TPC_ClassTemplate:
2781 case Sema::TPC_VarTemplate:
2782 case Sema::TPC_TypeAliasTemplate:
2783 return false;
2785 case Sema::TPC_FunctionTemplate:
2786 case Sema::TPC_FriendFunctionTemplateDefinition:
2787 // C++ [temp.param]p9:
2788 // A default template-argument shall not be specified in a
2789 // function template declaration or a function template
2790 // definition [...]
2791 // If a friend function template declaration specifies a default
2792 // template-argument, that declaration shall be a definition and shall be
2793 // the only declaration of the function template in the translation unit.
2794 // (C++98/03 doesn't have this wording; see DR226).
2795 S.Diag(ParamLoc, S.getLangOpts().CPlusPlus11 ?
2796 diag::warn_cxx98_compat_template_parameter_default_in_function_template
2797 : diag::ext_template_parameter_default_in_function_template)
2798 << DefArgRange;
2799 return false;
2801 case Sema::TPC_ClassTemplateMember:
2802 // C++0x [temp.param]p9:
2803 // A default template-argument shall not be specified in the
2804 // template-parameter-lists of the definition of a member of a
2805 // class template that appears outside of the member's class.
2806 S.Diag(ParamLoc, diag::err_template_parameter_default_template_member)
2807 << DefArgRange;
2808 return true;
2810 case Sema::TPC_FriendClassTemplate:
2811 case Sema::TPC_FriendFunctionTemplate:
2812 // C++ [temp.param]p9:
2813 // A default template-argument shall not be specified in a
2814 // friend template declaration.
2815 S.Diag(ParamLoc, diag::err_template_parameter_default_friend_template)
2816 << DefArgRange;
2817 return true;
2819 // FIXME: C++0x [temp.param]p9 allows default template-arguments
2820 // for friend function templates if there is only a single
2821 // declaration (and it is a definition). Strange!
2824 llvm_unreachable("Invalid TemplateParamListContext!");
2827 /// Check for unexpanded parameter packs within the template parameters
2828 /// of a template template parameter, recursively.
2829 static bool DiagnoseUnexpandedParameterPacks(Sema &S,
2830 TemplateTemplateParmDecl *TTP) {
2831 // A template template parameter which is a parameter pack is also a pack
2832 // expansion.
2833 if (TTP->isParameterPack())
2834 return false;
2836 TemplateParameterList *Params = TTP->getTemplateParameters();
2837 for (unsigned I = 0, N = Params->size(); I != N; ++I) {
2838 NamedDecl *P = Params->getParam(I);
2839 if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(P)) {
2840 if (!TTP->isParameterPack())
2841 if (const TypeConstraint *TC = TTP->getTypeConstraint())
2842 if (TC->hasExplicitTemplateArgs())
2843 for (auto &ArgLoc : TC->getTemplateArgsAsWritten()->arguments())
2844 if (S.DiagnoseUnexpandedParameterPack(ArgLoc,
2845 Sema::UPPC_TypeConstraint))
2846 return true;
2847 continue;
2850 if (NonTypeTemplateParmDecl *NTTP = dyn_cast<NonTypeTemplateParmDecl>(P)) {
2851 if (!NTTP->isParameterPack() &&
2852 S.DiagnoseUnexpandedParameterPack(NTTP->getLocation(),
2853 NTTP->getTypeSourceInfo(),
2854 Sema::UPPC_NonTypeTemplateParameterType))
2855 return true;
2857 continue;
2860 if (TemplateTemplateParmDecl *InnerTTP
2861 = dyn_cast<TemplateTemplateParmDecl>(P))
2862 if (DiagnoseUnexpandedParameterPacks(S, InnerTTP))
2863 return true;
2866 return false;
2869 /// Checks the validity of a template parameter list, possibly
2870 /// considering the template parameter list from a previous
2871 /// declaration.
2873 /// If an "old" template parameter list is provided, it must be
2874 /// equivalent (per TemplateParameterListsAreEqual) to the "new"
2875 /// template parameter list.
2877 /// \param NewParams Template parameter list for a new template
2878 /// declaration. This template parameter list will be updated with any
2879 /// default arguments that are carried through from the previous
2880 /// template parameter list.
2882 /// \param OldParams If provided, template parameter list from a
2883 /// previous declaration of the same template. Default template
2884 /// arguments will be merged from the old template parameter list to
2885 /// the new template parameter list.
2887 /// \param TPC Describes the context in which we are checking the given
2888 /// template parameter list.
2890 /// \param SkipBody If we might have already made a prior merged definition
2891 /// of this template visible, the corresponding body-skipping information.
2892 /// Default argument redefinition is not an error when skipping such a body,
2893 /// because (under the ODR) we can assume the default arguments are the same
2894 /// as the prior merged definition.
2896 /// \returns true if an error occurred, false otherwise.
2897 bool Sema::CheckTemplateParameterList(TemplateParameterList *NewParams,
2898 TemplateParameterList *OldParams,
2899 TemplateParamListContext TPC,
2900 SkipBodyInfo *SkipBody) {
2901 bool Invalid = false;
2903 // C++ [temp.param]p10:
2904 // The set of default template-arguments available for use with a
2905 // template declaration or definition is obtained by merging the
2906 // default arguments from the definition (if in scope) and all
2907 // declarations in scope in the same way default function
2908 // arguments are (8.3.6).
2909 bool SawDefaultArgument = false;
2910 SourceLocation PreviousDefaultArgLoc;
2912 // Dummy initialization to avoid warnings.
2913 TemplateParameterList::iterator OldParam = NewParams->end();
2914 if (OldParams)
2915 OldParam = OldParams->begin();
2917 bool RemoveDefaultArguments = false;
2918 for (TemplateParameterList::iterator NewParam = NewParams->begin(),
2919 NewParamEnd = NewParams->end();
2920 NewParam != NewParamEnd; ++NewParam) {
2921 // Whether we've seen a duplicate default argument in the same translation
2922 // unit.
2923 bool RedundantDefaultArg = false;
2924 // Whether we've found inconsis inconsitent default arguments in different
2925 // translation unit.
2926 bool InconsistentDefaultArg = false;
2927 // The name of the module which contains the inconsistent default argument.
2928 std::string PrevModuleName;
2930 SourceLocation OldDefaultLoc;
2931 SourceLocation NewDefaultLoc;
2933 // Variable used to diagnose missing default arguments
2934 bool MissingDefaultArg = false;
2936 // Variable used to diagnose non-final parameter packs
2937 bool SawParameterPack = false;
2939 if (TemplateTypeParmDecl *NewTypeParm
2940 = dyn_cast<TemplateTypeParmDecl>(*NewParam)) {
2941 // Check the presence of a default argument here.
2942 if (NewTypeParm->hasDefaultArgument() &&
2943 DiagnoseDefaultTemplateArgument(*this, TPC,
2944 NewTypeParm->getLocation(),
2945 NewTypeParm->getDefaultArgumentInfo()->getTypeLoc()
2946 .getSourceRange()))
2947 NewTypeParm->removeDefaultArgument();
2949 // Merge default arguments for template type parameters.
2950 TemplateTypeParmDecl *OldTypeParm
2951 = OldParams? cast<TemplateTypeParmDecl>(*OldParam) : nullptr;
2952 if (NewTypeParm->isParameterPack()) {
2953 assert(!NewTypeParm->hasDefaultArgument() &&
2954 "Parameter packs can't have a default argument!");
2955 SawParameterPack = true;
2956 } else if (OldTypeParm && hasVisibleDefaultArgument(OldTypeParm) &&
2957 NewTypeParm->hasDefaultArgument() &&
2958 (!SkipBody || !SkipBody->ShouldSkip)) {
2959 OldDefaultLoc = OldTypeParm->getDefaultArgumentLoc();
2960 NewDefaultLoc = NewTypeParm->getDefaultArgumentLoc();
2961 SawDefaultArgument = true;
2963 if (!OldTypeParm->getOwningModule())
2964 RedundantDefaultArg = true;
2965 else if (!getASTContext().isSameDefaultTemplateArgument(OldTypeParm,
2966 NewTypeParm)) {
2967 InconsistentDefaultArg = true;
2968 PrevModuleName =
2969 OldTypeParm->getImportedOwningModule()->getFullModuleName();
2971 PreviousDefaultArgLoc = NewDefaultLoc;
2972 } else if (OldTypeParm && OldTypeParm->hasDefaultArgument()) {
2973 // Merge the default argument from the old declaration to the
2974 // new declaration.
2975 NewTypeParm->setInheritedDefaultArgument(Context, OldTypeParm);
2976 PreviousDefaultArgLoc = OldTypeParm->getDefaultArgumentLoc();
2977 } else if (NewTypeParm->hasDefaultArgument()) {
2978 SawDefaultArgument = true;
2979 PreviousDefaultArgLoc = NewTypeParm->getDefaultArgumentLoc();
2980 } else if (SawDefaultArgument)
2981 MissingDefaultArg = true;
2982 } else if (NonTypeTemplateParmDecl *NewNonTypeParm
2983 = dyn_cast<NonTypeTemplateParmDecl>(*NewParam)) {
2984 // Check for unexpanded parameter packs.
2985 if (!NewNonTypeParm->isParameterPack() &&
2986 DiagnoseUnexpandedParameterPack(NewNonTypeParm->getLocation(),
2987 NewNonTypeParm->getTypeSourceInfo(),
2988 UPPC_NonTypeTemplateParameterType)) {
2989 Invalid = true;
2990 continue;
2993 // Check the presence of a default argument here.
2994 if (NewNonTypeParm->hasDefaultArgument() &&
2995 DiagnoseDefaultTemplateArgument(*this, TPC,
2996 NewNonTypeParm->getLocation(),
2997 NewNonTypeParm->getDefaultArgument()->getSourceRange())) {
2998 NewNonTypeParm->removeDefaultArgument();
3001 // Merge default arguments for non-type template parameters
3002 NonTypeTemplateParmDecl *OldNonTypeParm
3003 = OldParams? cast<NonTypeTemplateParmDecl>(*OldParam) : nullptr;
3004 if (NewNonTypeParm->isParameterPack()) {
3005 assert(!NewNonTypeParm->hasDefaultArgument() &&
3006 "Parameter packs can't have a default argument!");
3007 if (!NewNonTypeParm->isPackExpansion())
3008 SawParameterPack = true;
3009 } else if (OldNonTypeParm && hasVisibleDefaultArgument(OldNonTypeParm) &&
3010 NewNonTypeParm->hasDefaultArgument() &&
3011 (!SkipBody || !SkipBody->ShouldSkip)) {
3012 OldDefaultLoc = OldNonTypeParm->getDefaultArgumentLoc();
3013 NewDefaultLoc = NewNonTypeParm->getDefaultArgumentLoc();
3014 SawDefaultArgument = true;
3015 if (!OldNonTypeParm->getOwningModule())
3016 RedundantDefaultArg = true;
3017 else if (!getASTContext().isSameDefaultTemplateArgument(
3018 OldNonTypeParm, NewNonTypeParm)) {
3019 InconsistentDefaultArg = true;
3020 PrevModuleName =
3021 OldNonTypeParm->getImportedOwningModule()->getFullModuleName();
3023 PreviousDefaultArgLoc = NewDefaultLoc;
3024 } else if (OldNonTypeParm && OldNonTypeParm->hasDefaultArgument()) {
3025 // Merge the default argument from the old declaration to the
3026 // new declaration.
3027 NewNonTypeParm->setInheritedDefaultArgument(Context, OldNonTypeParm);
3028 PreviousDefaultArgLoc = OldNonTypeParm->getDefaultArgumentLoc();
3029 } else if (NewNonTypeParm->hasDefaultArgument()) {
3030 SawDefaultArgument = true;
3031 PreviousDefaultArgLoc = NewNonTypeParm->getDefaultArgumentLoc();
3032 } else if (SawDefaultArgument)
3033 MissingDefaultArg = true;
3034 } else {
3035 TemplateTemplateParmDecl *NewTemplateParm
3036 = cast<TemplateTemplateParmDecl>(*NewParam);
3038 // Check for unexpanded parameter packs, recursively.
3039 if (::DiagnoseUnexpandedParameterPacks(*this, NewTemplateParm)) {
3040 Invalid = true;
3041 continue;
3044 // Check the presence of a default argument here.
3045 if (NewTemplateParm->hasDefaultArgument() &&
3046 DiagnoseDefaultTemplateArgument(*this, TPC,
3047 NewTemplateParm->getLocation(),
3048 NewTemplateParm->getDefaultArgument().getSourceRange()))
3049 NewTemplateParm->removeDefaultArgument();
3051 // Merge default arguments for template template parameters
3052 TemplateTemplateParmDecl *OldTemplateParm
3053 = OldParams? cast<TemplateTemplateParmDecl>(*OldParam) : nullptr;
3054 if (NewTemplateParm->isParameterPack()) {
3055 assert(!NewTemplateParm->hasDefaultArgument() &&
3056 "Parameter packs can't have a default argument!");
3057 if (!NewTemplateParm->isPackExpansion())
3058 SawParameterPack = true;
3059 } else if (OldTemplateParm &&
3060 hasVisibleDefaultArgument(OldTemplateParm) &&
3061 NewTemplateParm->hasDefaultArgument() &&
3062 (!SkipBody || !SkipBody->ShouldSkip)) {
3063 OldDefaultLoc = OldTemplateParm->getDefaultArgument().getLocation();
3064 NewDefaultLoc = NewTemplateParm->getDefaultArgument().getLocation();
3065 SawDefaultArgument = true;
3066 if (!OldTemplateParm->getOwningModule())
3067 RedundantDefaultArg = true;
3068 else if (!getASTContext().isSameDefaultTemplateArgument(
3069 OldTemplateParm, NewTemplateParm)) {
3070 InconsistentDefaultArg = true;
3071 PrevModuleName =
3072 OldTemplateParm->getImportedOwningModule()->getFullModuleName();
3074 PreviousDefaultArgLoc = NewDefaultLoc;
3075 } else if (OldTemplateParm && OldTemplateParm->hasDefaultArgument()) {
3076 // Merge the default argument from the old declaration to the
3077 // new declaration.
3078 NewTemplateParm->setInheritedDefaultArgument(Context, OldTemplateParm);
3079 PreviousDefaultArgLoc
3080 = OldTemplateParm->getDefaultArgument().getLocation();
3081 } else if (NewTemplateParm->hasDefaultArgument()) {
3082 SawDefaultArgument = true;
3083 PreviousDefaultArgLoc
3084 = NewTemplateParm->getDefaultArgument().getLocation();
3085 } else if (SawDefaultArgument)
3086 MissingDefaultArg = true;
3089 // C++11 [temp.param]p11:
3090 // If a template parameter of a primary class template or alias template
3091 // is a template parameter pack, it shall be the last template parameter.
3092 if (SawParameterPack && (NewParam + 1) != NewParamEnd &&
3093 (TPC == TPC_ClassTemplate || TPC == TPC_VarTemplate ||
3094 TPC == TPC_TypeAliasTemplate)) {
3095 Diag((*NewParam)->getLocation(),
3096 diag::err_template_param_pack_must_be_last_template_parameter);
3097 Invalid = true;
3100 // [basic.def.odr]/13:
3101 // There can be more than one definition of a
3102 // ...
3103 // default template argument
3104 // ...
3105 // in a program provided that each definition appears in a different
3106 // translation unit and the definitions satisfy the [same-meaning
3107 // criteria of the ODR].
3109 // Simply, the design of modules allows the definition of template default
3110 // argument to be repeated across translation unit. Note that the ODR is
3111 // checked elsewhere. But it is still not allowed to repeat template default
3112 // argument in the same translation unit.
3113 if (RedundantDefaultArg) {
3114 Diag(NewDefaultLoc, diag::err_template_param_default_arg_redefinition);
3115 Diag(OldDefaultLoc, diag::note_template_param_prev_default_arg);
3116 Invalid = true;
3117 } else if (InconsistentDefaultArg) {
3118 // We could only diagnose about the case that the OldParam is imported.
3119 // The case NewParam is imported should be handled in ASTReader.
3120 Diag(NewDefaultLoc,
3121 diag::err_template_param_default_arg_inconsistent_redefinition);
3122 Diag(OldDefaultLoc,
3123 diag::note_template_param_prev_default_arg_in_other_module)
3124 << PrevModuleName;
3125 Invalid = true;
3126 } else if (MissingDefaultArg && TPC != TPC_FunctionTemplate) {
3127 // C++ [temp.param]p11:
3128 // If a template-parameter of a class template has a default
3129 // template-argument, each subsequent template-parameter shall either
3130 // have a default template-argument supplied or be a template parameter
3131 // pack.
3132 Diag((*NewParam)->getLocation(),
3133 diag::err_template_param_default_arg_missing);
3134 Diag(PreviousDefaultArgLoc, diag::note_template_param_prev_default_arg);
3135 Invalid = true;
3136 RemoveDefaultArguments = true;
3139 // If we have an old template parameter list that we're merging
3140 // in, move on to the next parameter.
3141 if (OldParams)
3142 ++OldParam;
3145 // We were missing some default arguments at the end of the list, so remove
3146 // all of the default arguments.
3147 if (RemoveDefaultArguments) {
3148 for (TemplateParameterList::iterator NewParam = NewParams->begin(),
3149 NewParamEnd = NewParams->end();
3150 NewParam != NewParamEnd; ++NewParam) {
3151 if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(*NewParam))
3152 TTP->removeDefaultArgument();
3153 else if (NonTypeTemplateParmDecl *NTTP
3154 = dyn_cast<NonTypeTemplateParmDecl>(*NewParam))
3155 NTTP->removeDefaultArgument();
3156 else
3157 cast<TemplateTemplateParmDecl>(*NewParam)->removeDefaultArgument();
3161 return Invalid;
3164 namespace {
3166 /// A class which looks for a use of a certain level of template
3167 /// parameter.
3168 struct DependencyChecker : RecursiveASTVisitor<DependencyChecker> {
3169 typedef RecursiveASTVisitor<DependencyChecker> super;
3171 unsigned Depth;
3173 // Whether we're looking for a use of a template parameter that makes the
3174 // overall construct type-dependent / a dependent type. This is strictly
3175 // best-effort for now; we may fail to match at all for a dependent type
3176 // in some cases if this is set.
3177 bool IgnoreNonTypeDependent;
3179 bool Match;
3180 SourceLocation MatchLoc;
3182 DependencyChecker(unsigned Depth, bool IgnoreNonTypeDependent)
3183 : Depth(Depth), IgnoreNonTypeDependent(IgnoreNonTypeDependent),
3184 Match(false) {}
3186 DependencyChecker(TemplateParameterList *Params, bool IgnoreNonTypeDependent)
3187 : IgnoreNonTypeDependent(IgnoreNonTypeDependent), Match(false) {
3188 NamedDecl *ND = Params->getParam(0);
3189 if (TemplateTypeParmDecl *PD = dyn_cast<TemplateTypeParmDecl>(ND)) {
3190 Depth = PD->getDepth();
3191 } else if (NonTypeTemplateParmDecl *PD =
3192 dyn_cast<NonTypeTemplateParmDecl>(ND)) {
3193 Depth = PD->getDepth();
3194 } else {
3195 Depth = cast<TemplateTemplateParmDecl>(ND)->getDepth();
3199 bool Matches(unsigned ParmDepth, SourceLocation Loc = SourceLocation()) {
3200 if (ParmDepth >= Depth) {
3201 Match = true;
3202 MatchLoc = Loc;
3203 return true;
3205 return false;
3208 bool TraverseStmt(Stmt *S, DataRecursionQueue *Q = nullptr) {
3209 // Prune out non-type-dependent expressions if requested. This can
3210 // sometimes result in us failing to find a template parameter reference
3211 // (if a value-dependent expression creates a dependent type), but this
3212 // mode is best-effort only.
3213 if (auto *E = dyn_cast_or_null<Expr>(S))
3214 if (IgnoreNonTypeDependent && !E->isTypeDependent())
3215 return true;
3216 return super::TraverseStmt(S, Q);
3219 bool TraverseTypeLoc(TypeLoc TL) {
3220 if (IgnoreNonTypeDependent && !TL.isNull() &&
3221 !TL.getType()->isDependentType())
3222 return true;
3223 return super::TraverseTypeLoc(TL);
3226 bool VisitTemplateTypeParmTypeLoc(TemplateTypeParmTypeLoc TL) {
3227 return !Matches(TL.getTypePtr()->getDepth(), TL.getNameLoc());
3230 bool VisitTemplateTypeParmType(const TemplateTypeParmType *T) {
3231 // For a best-effort search, keep looking until we find a location.
3232 return IgnoreNonTypeDependent || !Matches(T->getDepth());
3235 bool TraverseTemplateName(TemplateName N) {
3236 if (TemplateTemplateParmDecl *PD =
3237 dyn_cast_or_null<TemplateTemplateParmDecl>(N.getAsTemplateDecl()))
3238 if (Matches(PD->getDepth()))
3239 return false;
3240 return super::TraverseTemplateName(N);
3243 bool VisitDeclRefExpr(DeclRefExpr *E) {
3244 if (NonTypeTemplateParmDecl *PD =
3245 dyn_cast<NonTypeTemplateParmDecl>(E->getDecl()))
3246 if (Matches(PD->getDepth(), E->getExprLoc()))
3247 return false;
3248 return super::VisitDeclRefExpr(E);
3251 bool VisitSubstTemplateTypeParmType(const SubstTemplateTypeParmType *T) {
3252 return TraverseType(T->getReplacementType());
3255 bool
3256 VisitSubstTemplateTypeParmPackType(const SubstTemplateTypeParmPackType *T) {
3257 return TraverseTemplateArgument(T->getArgumentPack());
3260 bool TraverseInjectedClassNameType(const InjectedClassNameType *T) {
3261 return TraverseType(T->getInjectedSpecializationType());
3264 } // end anonymous namespace
3266 /// Determines whether a given type depends on the given parameter
3267 /// list.
3268 static bool
3269 DependsOnTemplateParameters(QualType T, TemplateParameterList *Params) {
3270 if (!Params->size())
3271 return false;
3273 DependencyChecker Checker(Params, /*IgnoreNonTypeDependent*/false);
3274 Checker.TraverseType(T);
3275 return Checker.Match;
3278 // Find the source range corresponding to the named type in the given
3279 // nested-name-specifier, if any.
3280 static SourceRange getRangeOfTypeInNestedNameSpecifier(ASTContext &Context,
3281 QualType T,
3282 const CXXScopeSpec &SS) {
3283 NestedNameSpecifierLoc NNSLoc(SS.getScopeRep(), SS.location_data());
3284 while (NestedNameSpecifier *NNS = NNSLoc.getNestedNameSpecifier()) {
3285 if (const Type *CurType = NNS->getAsType()) {
3286 if (Context.hasSameUnqualifiedType(T, QualType(CurType, 0)))
3287 return NNSLoc.getTypeLoc().getSourceRange();
3288 } else
3289 break;
3291 NNSLoc = NNSLoc.getPrefix();
3294 return SourceRange();
3297 /// Match the given template parameter lists to the given scope
3298 /// specifier, returning the template parameter list that applies to the
3299 /// name.
3301 /// \param DeclStartLoc the start of the declaration that has a scope
3302 /// specifier or a template parameter list.
3304 /// \param DeclLoc The location of the declaration itself.
3306 /// \param SS the scope specifier that will be matched to the given template
3307 /// parameter lists. This scope specifier precedes a qualified name that is
3308 /// being declared.
3310 /// \param TemplateId The template-id following the scope specifier, if there
3311 /// is one. Used to check for a missing 'template<>'.
3313 /// \param ParamLists the template parameter lists, from the outermost to the
3314 /// innermost template parameter lists.
3316 /// \param IsFriend Whether to apply the slightly different rules for
3317 /// matching template parameters to scope specifiers in friend
3318 /// declarations.
3320 /// \param IsMemberSpecialization will be set true if the scope specifier
3321 /// denotes a fully-specialized type, and therefore this is a declaration of
3322 /// a member specialization.
3324 /// \returns the template parameter list, if any, that corresponds to the
3325 /// name that is preceded by the scope specifier @p SS. This template
3326 /// parameter list may have template parameters (if we're declaring a
3327 /// template) or may have no template parameters (if we're declaring a
3328 /// template specialization), or may be NULL (if what we're declaring isn't
3329 /// itself a template).
3330 TemplateParameterList *Sema::MatchTemplateParametersToScopeSpecifier(
3331 SourceLocation DeclStartLoc, SourceLocation DeclLoc, const CXXScopeSpec &SS,
3332 TemplateIdAnnotation *TemplateId,
3333 ArrayRef<TemplateParameterList *> ParamLists, bool IsFriend,
3334 bool &IsMemberSpecialization, bool &Invalid, bool SuppressDiagnostic) {
3335 IsMemberSpecialization = false;
3336 Invalid = false;
3338 // The sequence of nested types to which we will match up the template
3339 // parameter lists. We first build this list by starting with the type named
3340 // by the nested-name-specifier and walking out until we run out of types.
3341 SmallVector<QualType, 4> NestedTypes;
3342 QualType T;
3343 if (SS.getScopeRep()) {
3344 if (CXXRecordDecl *Record
3345 = dyn_cast_or_null<CXXRecordDecl>(computeDeclContext(SS, true)))
3346 T = Context.getTypeDeclType(Record);
3347 else
3348 T = QualType(SS.getScopeRep()->getAsType(), 0);
3351 // If we found an explicit specialization that prevents us from needing
3352 // 'template<>' headers, this will be set to the location of that
3353 // explicit specialization.
3354 SourceLocation ExplicitSpecLoc;
3356 while (!T.isNull()) {
3357 NestedTypes.push_back(T);
3359 // Retrieve the parent of a record type.
3360 if (CXXRecordDecl *Record = T->getAsCXXRecordDecl()) {
3361 // If this type is an explicit specialization, we're done.
3362 if (ClassTemplateSpecializationDecl *Spec
3363 = dyn_cast<ClassTemplateSpecializationDecl>(Record)) {
3364 if (!isa<ClassTemplatePartialSpecializationDecl>(Spec) &&
3365 Spec->getSpecializationKind() == TSK_ExplicitSpecialization) {
3366 ExplicitSpecLoc = Spec->getLocation();
3367 break;
3369 } else if (Record->getTemplateSpecializationKind()
3370 == TSK_ExplicitSpecialization) {
3371 ExplicitSpecLoc = Record->getLocation();
3372 break;
3375 if (TypeDecl *Parent = dyn_cast<TypeDecl>(Record->getParent()))
3376 T = Context.getTypeDeclType(Parent);
3377 else
3378 T = QualType();
3379 continue;
3382 if (const TemplateSpecializationType *TST
3383 = T->getAs<TemplateSpecializationType>()) {
3384 if (TemplateDecl *Template = TST->getTemplateName().getAsTemplateDecl()) {
3385 if (TypeDecl *Parent = dyn_cast<TypeDecl>(Template->getDeclContext()))
3386 T = Context.getTypeDeclType(Parent);
3387 else
3388 T = QualType();
3389 continue;
3393 // Look one step prior in a dependent template specialization type.
3394 if (const DependentTemplateSpecializationType *DependentTST
3395 = T->getAs<DependentTemplateSpecializationType>()) {
3396 if (NestedNameSpecifier *NNS = DependentTST->getQualifier())
3397 T = QualType(NNS->getAsType(), 0);
3398 else
3399 T = QualType();
3400 continue;
3403 // Look one step prior in a dependent name type.
3404 if (const DependentNameType *DependentName = T->getAs<DependentNameType>()){
3405 if (NestedNameSpecifier *NNS = DependentName->getQualifier())
3406 T = QualType(NNS->getAsType(), 0);
3407 else
3408 T = QualType();
3409 continue;
3412 // Retrieve the parent of an enumeration type.
3413 if (const EnumType *EnumT = T->getAs<EnumType>()) {
3414 // FIXME: Forward-declared enums require a TSK_ExplicitSpecialization
3415 // check here.
3416 EnumDecl *Enum = EnumT->getDecl();
3418 // Get to the parent type.
3419 if (TypeDecl *Parent = dyn_cast<TypeDecl>(Enum->getParent()))
3420 T = Context.getTypeDeclType(Parent);
3421 else
3422 T = QualType();
3423 continue;
3426 T = QualType();
3428 // Reverse the nested types list, since we want to traverse from the outermost
3429 // to the innermost while checking template-parameter-lists.
3430 std::reverse(NestedTypes.begin(), NestedTypes.end());
3432 // C++0x [temp.expl.spec]p17:
3433 // A member or a member template may be nested within many
3434 // enclosing class templates. In an explicit specialization for
3435 // such a member, the member declaration shall be preceded by a
3436 // template<> for each enclosing class template that is
3437 // explicitly specialized.
3438 bool SawNonEmptyTemplateParameterList = false;
3440 auto CheckExplicitSpecialization = [&](SourceRange Range, bool Recovery) {
3441 if (SawNonEmptyTemplateParameterList) {
3442 if (!SuppressDiagnostic)
3443 Diag(DeclLoc, diag::err_specialize_member_of_template)
3444 << !Recovery << Range;
3445 Invalid = true;
3446 IsMemberSpecialization = false;
3447 return true;
3450 return false;
3453 auto DiagnoseMissingExplicitSpecialization = [&] (SourceRange Range) {
3454 // Check that we can have an explicit specialization here.
3455 if (CheckExplicitSpecialization(Range, true))
3456 return true;
3458 // We don't have a template header, but we should.
3459 SourceLocation ExpectedTemplateLoc;
3460 if (!ParamLists.empty())
3461 ExpectedTemplateLoc = ParamLists[0]->getTemplateLoc();
3462 else
3463 ExpectedTemplateLoc = DeclStartLoc;
3465 if (!SuppressDiagnostic)
3466 Diag(DeclLoc, diag::err_template_spec_needs_header)
3467 << Range
3468 << FixItHint::CreateInsertion(ExpectedTemplateLoc, "template<> ");
3469 return false;
3472 unsigned ParamIdx = 0;
3473 for (unsigned TypeIdx = 0, NumTypes = NestedTypes.size(); TypeIdx != NumTypes;
3474 ++TypeIdx) {
3475 T = NestedTypes[TypeIdx];
3477 // Whether we expect a 'template<>' header.
3478 bool NeedEmptyTemplateHeader = false;
3480 // Whether we expect a template header with parameters.
3481 bool NeedNonemptyTemplateHeader = false;
3483 // For a dependent type, the set of template parameters that we
3484 // expect to see.
3485 TemplateParameterList *ExpectedTemplateParams = nullptr;
3487 // C++0x [temp.expl.spec]p15:
3488 // A member or a member template may be nested within many enclosing
3489 // class templates. In an explicit specialization for such a member, the
3490 // member declaration shall be preceded by a template<> for each
3491 // enclosing class template that is explicitly specialized.
3492 if (CXXRecordDecl *Record = T->getAsCXXRecordDecl()) {
3493 if (ClassTemplatePartialSpecializationDecl *Partial
3494 = dyn_cast<ClassTemplatePartialSpecializationDecl>(Record)) {
3495 ExpectedTemplateParams = Partial->getTemplateParameters();
3496 NeedNonemptyTemplateHeader = true;
3497 } else if (Record->isDependentType()) {
3498 if (Record->getDescribedClassTemplate()) {
3499 ExpectedTemplateParams = Record->getDescribedClassTemplate()
3500 ->getTemplateParameters();
3501 NeedNonemptyTemplateHeader = true;
3503 } else if (ClassTemplateSpecializationDecl *Spec
3504 = dyn_cast<ClassTemplateSpecializationDecl>(Record)) {
3505 // C++0x [temp.expl.spec]p4:
3506 // Members of an explicitly specialized class template are defined
3507 // in the same manner as members of normal classes, and not using
3508 // the template<> syntax.
3509 if (Spec->getSpecializationKind() != TSK_ExplicitSpecialization)
3510 NeedEmptyTemplateHeader = true;
3511 else
3512 continue;
3513 } else if (Record->getTemplateSpecializationKind()) {
3514 if (Record->getTemplateSpecializationKind()
3515 != TSK_ExplicitSpecialization &&
3516 TypeIdx == NumTypes - 1)
3517 IsMemberSpecialization = true;
3519 continue;
3521 } else if (const TemplateSpecializationType *TST
3522 = T->getAs<TemplateSpecializationType>()) {
3523 if (TemplateDecl *Template = TST->getTemplateName().getAsTemplateDecl()) {
3524 ExpectedTemplateParams = Template->getTemplateParameters();
3525 NeedNonemptyTemplateHeader = true;
3527 } else if (T->getAs<DependentTemplateSpecializationType>()) {
3528 // FIXME: We actually could/should check the template arguments here
3529 // against the corresponding template parameter list.
3530 NeedNonemptyTemplateHeader = false;
3533 // C++ [temp.expl.spec]p16:
3534 // In an explicit specialization declaration for a member of a class
3535 // template or a member template that ap- pears in namespace scope, the
3536 // member template and some of its enclosing class templates may remain
3537 // unspecialized, except that the declaration shall not explicitly
3538 // specialize a class member template if its en- closing class templates
3539 // are not explicitly specialized as well.
3540 if (ParamIdx < ParamLists.size()) {
3541 if (ParamLists[ParamIdx]->size() == 0) {
3542 if (CheckExplicitSpecialization(ParamLists[ParamIdx]->getSourceRange(),
3543 false))
3544 return nullptr;
3545 } else
3546 SawNonEmptyTemplateParameterList = true;
3549 if (NeedEmptyTemplateHeader) {
3550 // If we're on the last of the types, and we need a 'template<>' header
3551 // here, then it's a member specialization.
3552 if (TypeIdx == NumTypes - 1)
3553 IsMemberSpecialization = true;
3555 if (ParamIdx < ParamLists.size()) {
3556 if (ParamLists[ParamIdx]->size() > 0) {
3557 // The header has template parameters when it shouldn't. Complain.
3558 if (!SuppressDiagnostic)
3559 Diag(ParamLists[ParamIdx]->getTemplateLoc(),
3560 diag::err_template_param_list_matches_nontemplate)
3561 << T
3562 << SourceRange(ParamLists[ParamIdx]->getLAngleLoc(),
3563 ParamLists[ParamIdx]->getRAngleLoc())
3564 << getRangeOfTypeInNestedNameSpecifier(Context, T, SS);
3565 Invalid = true;
3566 return nullptr;
3569 // Consume this template header.
3570 ++ParamIdx;
3571 continue;
3574 if (!IsFriend)
3575 if (DiagnoseMissingExplicitSpecialization(
3576 getRangeOfTypeInNestedNameSpecifier(Context, T, SS)))
3577 return nullptr;
3579 continue;
3582 if (NeedNonemptyTemplateHeader) {
3583 // In friend declarations we can have template-ids which don't
3584 // depend on the corresponding template parameter lists. But
3585 // assume that empty parameter lists are supposed to match this
3586 // template-id.
3587 if (IsFriend && T->isDependentType()) {
3588 if (ParamIdx < ParamLists.size() &&
3589 DependsOnTemplateParameters(T, ParamLists[ParamIdx]))
3590 ExpectedTemplateParams = nullptr;
3591 else
3592 continue;
3595 if (ParamIdx < ParamLists.size()) {
3596 // Check the template parameter list, if we can.
3597 if (ExpectedTemplateParams &&
3598 !TemplateParameterListsAreEqual(ParamLists[ParamIdx],
3599 ExpectedTemplateParams,
3600 !SuppressDiagnostic, TPL_TemplateMatch))
3601 Invalid = true;
3603 if (!Invalid &&
3604 CheckTemplateParameterList(ParamLists[ParamIdx], nullptr,
3605 TPC_ClassTemplateMember))
3606 Invalid = true;
3608 ++ParamIdx;
3609 continue;
3612 if (!SuppressDiagnostic)
3613 Diag(DeclLoc, diag::err_template_spec_needs_template_parameters)
3614 << T
3615 << getRangeOfTypeInNestedNameSpecifier(Context, T, SS);
3616 Invalid = true;
3617 continue;
3621 // If there were at least as many template-ids as there were template
3622 // parameter lists, then there are no template parameter lists remaining for
3623 // the declaration itself.
3624 if (ParamIdx >= ParamLists.size()) {
3625 if (TemplateId && !IsFriend) {
3626 // We don't have a template header for the declaration itself, but we
3627 // should.
3628 DiagnoseMissingExplicitSpecialization(SourceRange(TemplateId->LAngleLoc,
3629 TemplateId->RAngleLoc));
3631 // Fabricate an empty template parameter list for the invented header.
3632 return TemplateParameterList::Create(Context, SourceLocation(),
3633 SourceLocation(), std::nullopt,
3634 SourceLocation(), nullptr);
3637 return nullptr;
3640 // If there were too many template parameter lists, complain about that now.
3641 if (ParamIdx < ParamLists.size() - 1) {
3642 bool HasAnyExplicitSpecHeader = false;
3643 bool AllExplicitSpecHeaders = true;
3644 for (unsigned I = ParamIdx, E = ParamLists.size() - 1; I != E; ++I) {
3645 if (ParamLists[I]->size() == 0)
3646 HasAnyExplicitSpecHeader = true;
3647 else
3648 AllExplicitSpecHeaders = false;
3651 if (!SuppressDiagnostic)
3652 Diag(ParamLists[ParamIdx]->getTemplateLoc(),
3653 AllExplicitSpecHeaders ? diag::warn_template_spec_extra_headers
3654 : diag::err_template_spec_extra_headers)
3655 << SourceRange(ParamLists[ParamIdx]->getTemplateLoc(),
3656 ParamLists[ParamLists.size() - 2]->getRAngleLoc());
3658 // If there was a specialization somewhere, such that 'template<>' is
3659 // not required, and there were any 'template<>' headers, note where the
3660 // specialization occurred.
3661 if (ExplicitSpecLoc.isValid() && HasAnyExplicitSpecHeader &&
3662 !SuppressDiagnostic)
3663 Diag(ExplicitSpecLoc,
3664 diag::note_explicit_template_spec_does_not_need_header)
3665 << NestedTypes.back();
3667 // We have a template parameter list with no corresponding scope, which
3668 // means that the resulting template declaration can't be instantiated
3669 // properly (we'll end up with dependent nodes when we shouldn't).
3670 if (!AllExplicitSpecHeaders)
3671 Invalid = true;
3674 // C++ [temp.expl.spec]p16:
3675 // In an explicit specialization declaration for a member of a class
3676 // template or a member template that ap- pears in namespace scope, the
3677 // member template and some of its enclosing class templates may remain
3678 // unspecialized, except that the declaration shall not explicitly
3679 // specialize a class member template if its en- closing class templates
3680 // are not explicitly specialized as well.
3681 if (ParamLists.back()->size() == 0 &&
3682 CheckExplicitSpecialization(ParamLists[ParamIdx]->getSourceRange(),
3683 false))
3684 return nullptr;
3686 // Return the last template parameter list, which corresponds to the
3687 // entity being declared.
3688 return ParamLists.back();
3691 void Sema::NoteAllFoundTemplates(TemplateName Name) {
3692 if (TemplateDecl *Template = Name.getAsTemplateDecl()) {
3693 Diag(Template->getLocation(), diag::note_template_declared_here)
3694 << (isa<FunctionTemplateDecl>(Template)
3696 : isa<ClassTemplateDecl>(Template)
3698 : isa<VarTemplateDecl>(Template)
3700 : isa<TypeAliasTemplateDecl>(Template) ? 3 : 4)
3701 << Template->getDeclName();
3702 return;
3705 if (OverloadedTemplateStorage *OST = Name.getAsOverloadedTemplate()) {
3706 for (OverloadedTemplateStorage::iterator I = OST->begin(),
3707 IEnd = OST->end();
3708 I != IEnd; ++I)
3709 Diag((*I)->getLocation(), diag::note_template_declared_here)
3710 << 0 << (*I)->getDeclName();
3712 return;
3716 static QualType
3717 checkBuiltinTemplateIdType(Sema &SemaRef, BuiltinTemplateDecl *BTD,
3718 ArrayRef<TemplateArgument> Converted,
3719 SourceLocation TemplateLoc,
3720 TemplateArgumentListInfo &TemplateArgs) {
3721 ASTContext &Context = SemaRef.getASTContext();
3723 switch (BTD->getBuiltinTemplateKind()) {
3724 case BTK__make_integer_seq: {
3725 // Specializations of __make_integer_seq<S, T, N> are treated like
3726 // S<T, 0, ..., N-1>.
3728 QualType OrigType = Converted[1].getAsType();
3729 // C++14 [inteseq.intseq]p1:
3730 // T shall be an integer type.
3731 if (!OrigType->isDependentType() && !OrigType->isIntegralType(Context)) {
3732 SemaRef.Diag(TemplateArgs[1].getLocation(),
3733 diag::err_integer_sequence_integral_element_type);
3734 return QualType();
3737 TemplateArgument NumArgsArg = Converted[2];
3738 if (NumArgsArg.isDependent())
3739 return Context.getCanonicalTemplateSpecializationType(TemplateName(BTD),
3740 Converted);
3742 TemplateArgumentListInfo SyntheticTemplateArgs;
3743 // The type argument, wrapped in substitution sugar, gets reused as the
3744 // first template argument in the synthetic template argument list.
3745 SyntheticTemplateArgs.addArgument(
3746 TemplateArgumentLoc(TemplateArgument(OrigType),
3747 SemaRef.Context.getTrivialTypeSourceInfo(
3748 OrigType, TemplateArgs[1].getLocation())));
3750 if (llvm::APSInt NumArgs = NumArgsArg.getAsIntegral(); NumArgs >= 0) {
3751 // Expand N into 0 ... N-1.
3752 for (llvm::APSInt I(NumArgs.getBitWidth(), NumArgs.isUnsigned());
3753 I < NumArgs; ++I) {
3754 TemplateArgument TA(Context, I, OrigType);
3755 SyntheticTemplateArgs.addArgument(SemaRef.getTrivialTemplateArgumentLoc(
3756 TA, OrigType, TemplateArgs[2].getLocation()));
3758 } else {
3759 // C++14 [inteseq.make]p1:
3760 // If N is negative the program is ill-formed.
3761 SemaRef.Diag(TemplateArgs[2].getLocation(),
3762 diag::err_integer_sequence_negative_length);
3763 return QualType();
3766 // The first template argument will be reused as the template decl that
3767 // our synthetic template arguments will be applied to.
3768 return SemaRef.CheckTemplateIdType(Converted[0].getAsTemplate(),
3769 TemplateLoc, SyntheticTemplateArgs);
3772 case BTK__type_pack_element:
3773 // Specializations of
3774 // __type_pack_element<Index, T_1, ..., T_N>
3775 // are treated like T_Index.
3776 assert(Converted.size() == 2 &&
3777 "__type_pack_element should be given an index and a parameter pack");
3779 TemplateArgument IndexArg = Converted[0], Ts = Converted[1];
3780 if (IndexArg.isDependent() || Ts.isDependent())
3781 return Context.getCanonicalTemplateSpecializationType(TemplateName(BTD),
3782 Converted);
3784 llvm::APSInt Index = IndexArg.getAsIntegral();
3785 assert(Index >= 0 && "the index used with __type_pack_element should be of "
3786 "type std::size_t, and hence be non-negative");
3787 // If the Index is out of bounds, the program is ill-formed.
3788 if (Index >= Ts.pack_size()) {
3789 SemaRef.Diag(TemplateArgs[0].getLocation(),
3790 diag::err_type_pack_element_out_of_bounds);
3791 return QualType();
3794 // We simply return the type at index `Index`.
3795 int64_t N = Index.getExtValue();
3796 return Ts.getPackAsArray()[N].getAsType();
3798 llvm_unreachable("unexpected BuiltinTemplateDecl!");
3801 /// Determine whether this alias template is "enable_if_t".
3802 /// libc++ >=14 uses "__enable_if_t" in C++11 mode.
3803 static bool isEnableIfAliasTemplate(TypeAliasTemplateDecl *AliasTemplate) {
3804 return AliasTemplate->getName().equals("enable_if_t") ||
3805 AliasTemplate->getName().equals("__enable_if_t");
3808 /// Collect all of the separable terms in the given condition, which
3809 /// might be a conjunction.
3811 /// FIXME: The right answer is to convert the logical expression into
3812 /// disjunctive normal form, so we can find the first failed term
3813 /// within each possible clause.
3814 static void collectConjunctionTerms(Expr *Clause,
3815 SmallVectorImpl<Expr *> &Terms) {
3816 if (auto BinOp = dyn_cast<BinaryOperator>(Clause->IgnoreParenImpCasts())) {
3817 if (BinOp->getOpcode() == BO_LAnd) {
3818 collectConjunctionTerms(BinOp->getLHS(), Terms);
3819 collectConjunctionTerms(BinOp->getRHS(), Terms);
3820 return;
3824 Terms.push_back(Clause);
3827 // The ranges-v3 library uses an odd pattern of a top-level "||" with
3828 // a left-hand side that is value-dependent but never true. Identify
3829 // the idiom and ignore that term.
3830 static Expr *lookThroughRangesV3Condition(Preprocessor &PP, Expr *Cond) {
3831 // Top-level '||'.
3832 auto *BinOp = dyn_cast<BinaryOperator>(Cond->IgnoreParenImpCasts());
3833 if (!BinOp) return Cond;
3835 if (BinOp->getOpcode() != BO_LOr) return Cond;
3837 // With an inner '==' that has a literal on the right-hand side.
3838 Expr *LHS = BinOp->getLHS();
3839 auto *InnerBinOp = dyn_cast<BinaryOperator>(LHS->IgnoreParenImpCasts());
3840 if (!InnerBinOp) return Cond;
3842 if (InnerBinOp->getOpcode() != BO_EQ ||
3843 !isa<IntegerLiteral>(InnerBinOp->getRHS()))
3844 return Cond;
3846 // If the inner binary operation came from a macro expansion named
3847 // CONCEPT_REQUIRES or CONCEPT_REQUIRES_, return the right-hand side
3848 // of the '||', which is the real, user-provided condition.
3849 SourceLocation Loc = InnerBinOp->getExprLoc();
3850 if (!Loc.isMacroID()) return Cond;
3852 StringRef MacroName = PP.getImmediateMacroName(Loc);
3853 if (MacroName == "CONCEPT_REQUIRES" || MacroName == "CONCEPT_REQUIRES_")
3854 return BinOp->getRHS();
3856 return Cond;
3859 namespace {
3861 // A PrinterHelper that prints more helpful diagnostics for some sub-expressions
3862 // within failing boolean expression, such as substituting template parameters
3863 // for actual types.
3864 class FailedBooleanConditionPrinterHelper : public PrinterHelper {
3865 public:
3866 explicit FailedBooleanConditionPrinterHelper(const PrintingPolicy &P)
3867 : Policy(P) {}
3869 bool handledStmt(Stmt *E, raw_ostream &OS) override {
3870 const auto *DR = dyn_cast<DeclRefExpr>(E);
3871 if (DR && DR->getQualifier()) {
3872 // If this is a qualified name, expand the template arguments in nested
3873 // qualifiers.
3874 DR->getQualifier()->print(OS, Policy, true);
3875 // Then print the decl itself.
3876 const ValueDecl *VD = DR->getDecl();
3877 OS << VD->getName();
3878 if (const auto *IV = dyn_cast<VarTemplateSpecializationDecl>(VD)) {
3879 // This is a template variable, print the expanded template arguments.
3880 printTemplateArgumentList(
3881 OS, IV->getTemplateArgs().asArray(), Policy,
3882 IV->getSpecializedTemplate()->getTemplateParameters());
3884 return true;
3886 return false;
3889 private:
3890 const PrintingPolicy Policy;
3893 } // end anonymous namespace
3895 std::pair<Expr *, std::string>
3896 Sema::findFailedBooleanCondition(Expr *Cond) {
3897 Cond = lookThroughRangesV3Condition(PP, Cond);
3899 // Separate out all of the terms in a conjunction.
3900 SmallVector<Expr *, 4> Terms;
3901 collectConjunctionTerms(Cond, Terms);
3903 // Determine which term failed.
3904 Expr *FailedCond = nullptr;
3905 for (Expr *Term : Terms) {
3906 Expr *TermAsWritten = Term->IgnoreParenImpCasts();
3908 // Literals are uninteresting.
3909 if (isa<CXXBoolLiteralExpr>(TermAsWritten) ||
3910 isa<IntegerLiteral>(TermAsWritten))
3911 continue;
3913 // The initialization of the parameter from the argument is
3914 // a constant-evaluated context.
3915 EnterExpressionEvaluationContext ConstantEvaluated(
3916 *this, Sema::ExpressionEvaluationContext::ConstantEvaluated);
3918 bool Succeeded;
3919 if (Term->EvaluateAsBooleanCondition(Succeeded, Context) &&
3920 !Succeeded) {
3921 FailedCond = TermAsWritten;
3922 break;
3925 if (!FailedCond)
3926 FailedCond = Cond->IgnoreParenImpCasts();
3928 std::string Description;
3930 llvm::raw_string_ostream Out(Description);
3931 PrintingPolicy Policy = getPrintingPolicy();
3932 Policy.PrintCanonicalTypes = true;
3933 FailedBooleanConditionPrinterHelper Helper(Policy);
3934 FailedCond->printPretty(Out, &Helper, Policy, 0, "\n", nullptr);
3936 return { FailedCond, Description };
3939 QualType Sema::CheckTemplateIdType(TemplateName Name,
3940 SourceLocation TemplateLoc,
3941 TemplateArgumentListInfo &TemplateArgs) {
3942 DependentTemplateName *DTN
3943 = Name.getUnderlying().getAsDependentTemplateName();
3944 if (DTN && DTN->isIdentifier())
3945 // When building a template-id where the template-name is dependent,
3946 // assume the template is a type template. Either our assumption is
3947 // correct, or the code is ill-formed and will be diagnosed when the
3948 // dependent name is substituted.
3949 return Context.getDependentTemplateSpecializationType(
3950 ElaboratedTypeKeyword::None, DTN->getQualifier(), DTN->getIdentifier(),
3951 TemplateArgs.arguments());
3953 if (Name.getAsAssumedTemplateName() &&
3954 resolveAssumedTemplateNameAsType(/*Scope*/nullptr, Name, TemplateLoc))
3955 return QualType();
3957 TemplateDecl *Template = Name.getAsTemplateDecl();
3958 if (!Template || isa<FunctionTemplateDecl>(Template) ||
3959 isa<VarTemplateDecl>(Template) || isa<ConceptDecl>(Template)) {
3960 // We might have a substituted template template parameter pack. If so,
3961 // build a template specialization type for it.
3962 if (Name.getAsSubstTemplateTemplateParmPack())
3963 return Context.getTemplateSpecializationType(Name,
3964 TemplateArgs.arguments());
3966 Diag(TemplateLoc, diag::err_template_id_not_a_type)
3967 << Name;
3968 NoteAllFoundTemplates(Name);
3969 return QualType();
3972 // Check that the template argument list is well-formed for this
3973 // template.
3974 SmallVector<TemplateArgument, 4> SugaredConverted, CanonicalConverted;
3975 if (CheckTemplateArgumentList(Template, TemplateLoc, TemplateArgs, false,
3976 SugaredConverted, CanonicalConverted,
3977 /*UpdateArgsWithConversions=*/true))
3978 return QualType();
3980 QualType CanonType;
3982 if (TypeAliasTemplateDecl *AliasTemplate =
3983 dyn_cast<TypeAliasTemplateDecl>(Template)) {
3985 // Find the canonical type for this type alias template specialization.
3986 TypeAliasDecl *Pattern = AliasTemplate->getTemplatedDecl();
3987 if (Pattern->isInvalidDecl())
3988 return QualType();
3990 // Only substitute for the innermost template argument list.
3991 MultiLevelTemplateArgumentList TemplateArgLists;
3992 TemplateArgLists.addOuterTemplateArguments(Template, CanonicalConverted,
3993 /*Final=*/false);
3994 TemplateArgLists.addOuterRetainedLevels(
3995 AliasTemplate->getTemplateParameters()->getDepth());
3997 LocalInstantiationScope Scope(*this);
3998 InstantiatingTemplate Inst(*this, TemplateLoc, Template);
3999 if (Inst.isInvalid())
4000 return QualType();
4002 CanonType = SubstType(Pattern->getUnderlyingType(),
4003 TemplateArgLists, AliasTemplate->getLocation(),
4004 AliasTemplate->getDeclName());
4005 if (CanonType.isNull()) {
4006 // If this was enable_if and we failed to find the nested type
4007 // within enable_if in a SFINAE context, dig out the specific
4008 // enable_if condition that failed and present that instead.
4009 if (isEnableIfAliasTemplate(AliasTemplate)) {
4010 if (auto DeductionInfo = isSFINAEContext()) {
4011 if (*DeductionInfo &&
4012 (*DeductionInfo)->hasSFINAEDiagnostic() &&
4013 (*DeductionInfo)->peekSFINAEDiagnostic().second.getDiagID() ==
4014 diag::err_typename_nested_not_found_enable_if &&
4015 TemplateArgs[0].getArgument().getKind()
4016 == TemplateArgument::Expression) {
4017 Expr *FailedCond;
4018 std::string FailedDescription;
4019 std::tie(FailedCond, FailedDescription) =
4020 findFailedBooleanCondition(TemplateArgs[0].getSourceExpression());
4022 // Remove the old SFINAE diagnostic.
4023 PartialDiagnosticAt OldDiag =
4024 {SourceLocation(), PartialDiagnostic::NullDiagnostic()};
4025 (*DeductionInfo)->takeSFINAEDiagnostic(OldDiag);
4027 // Add a new SFINAE diagnostic specifying which condition
4028 // failed.
4029 (*DeductionInfo)->addSFINAEDiagnostic(
4030 OldDiag.first,
4031 PDiag(diag::err_typename_nested_not_found_requirement)
4032 << FailedDescription
4033 << FailedCond->getSourceRange());
4038 return QualType();
4040 } else if (auto *BTD = dyn_cast<BuiltinTemplateDecl>(Template)) {
4041 CanonType = checkBuiltinTemplateIdType(*this, BTD, SugaredConverted,
4042 TemplateLoc, TemplateArgs);
4043 } else if (Name.isDependent() ||
4044 TemplateSpecializationType::anyDependentTemplateArguments(
4045 TemplateArgs, CanonicalConverted)) {
4046 // This class template specialization is a dependent
4047 // type. Therefore, its canonical type is another class template
4048 // specialization type that contains all of the converted
4049 // arguments in canonical form. This ensures that, e.g., A<T> and
4050 // A<T, T> have identical types when A is declared as:
4052 // template<typename T, typename U = T> struct A;
4053 CanonType = Context.getCanonicalTemplateSpecializationType(
4054 Name, CanonicalConverted);
4056 // This might work out to be a current instantiation, in which
4057 // case the canonical type needs to be the InjectedClassNameType.
4059 // TODO: in theory this could be a simple hashtable lookup; most
4060 // changes to CurContext don't change the set of current
4061 // instantiations.
4062 if (isa<ClassTemplateDecl>(Template)) {
4063 for (DeclContext *Ctx = CurContext; Ctx; Ctx = Ctx->getLookupParent()) {
4064 // If we get out to a namespace, we're done.
4065 if (Ctx->isFileContext()) break;
4067 // If this isn't a record, keep looking.
4068 CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(Ctx);
4069 if (!Record) continue;
4071 // Look for one of the two cases with InjectedClassNameTypes
4072 // and check whether it's the same template.
4073 if (!isa<ClassTemplatePartialSpecializationDecl>(Record) &&
4074 !Record->getDescribedClassTemplate())
4075 continue;
4077 // Fetch the injected class name type and check whether its
4078 // injected type is equal to the type we just built.
4079 QualType ICNT = Context.getTypeDeclType(Record);
4080 QualType Injected = cast<InjectedClassNameType>(ICNT)
4081 ->getInjectedSpecializationType();
4083 if (CanonType != Injected->getCanonicalTypeInternal())
4084 continue;
4086 // If so, the canonical type of this TST is the injected
4087 // class name type of the record we just found.
4088 assert(ICNT.isCanonical());
4089 CanonType = ICNT;
4090 break;
4093 } else if (ClassTemplateDecl *ClassTemplate =
4094 dyn_cast<ClassTemplateDecl>(Template)) {
4095 // Find the class template specialization declaration that
4096 // corresponds to these arguments.
4097 void *InsertPos = nullptr;
4098 ClassTemplateSpecializationDecl *Decl =
4099 ClassTemplate->findSpecialization(CanonicalConverted, InsertPos);
4100 if (!Decl) {
4101 // This is the first time we have referenced this class template
4102 // specialization. Create the canonical declaration and add it to
4103 // the set of specializations.
4104 Decl = ClassTemplateSpecializationDecl::Create(
4105 Context, ClassTemplate->getTemplatedDecl()->getTagKind(),
4106 ClassTemplate->getDeclContext(),
4107 ClassTemplate->getTemplatedDecl()->getBeginLoc(),
4108 ClassTemplate->getLocation(), ClassTemplate, CanonicalConverted,
4109 nullptr);
4110 ClassTemplate->AddSpecialization(Decl, InsertPos);
4111 if (ClassTemplate->isOutOfLine())
4112 Decl->setLexicalDeclContext(ClassTemplate->getLexicalDeclContext());
4115 if (Decl->getSpecializationKind() == TSK_Undeclared &&
4116 ClassTemplate->getTemplatedDecl()->hasAttrs()) {
4117 InstantiatingTemplate Inst(*this, TemplateLoc, Decl);
4118 if (!Inst.isInvalid()) {
4119 MultiLevelTemplateArgumentList TemplateArgLists(Template,
4120 CanonicalConverted,
4121 /*Final=*/false);
4122 InstantiateAttrsForDecl(TemplateArgLists,
4123 ClassTemplate->getTemplatedDecl(), Decl);
4127 // Diagnose uses of this specialization.
4128 (void)DiagnoseUseOfDecl(Decl, TemplateLoc);
4130 CanonType = Context.getTypeDeclType(Decl);
4131 assert(isa<RecordType>(CanonType) &&
4132 "type of non-dependent specialization is not a RecordType");
4133 } else {
4134 llvm_unreachable("Unhandled template kind");
4137 // Build the fully-sugared type for this class template
4138 // specialization, which refers back to the class template
4139 // specialization we created or found.
4140 return Context.getTemplateSpecializationType(Name, TemplateArgs.arguments(),
4141 CanonType);
4144 void Sema::ActOnUndeclaredTypeTemplateName(Scope *S, TemplateTy &ParsedName,
4145 TemplateNameKind &TNK,
4146 SourceLocation NameLoc,
4147 IdentifierInfo *&II) {
4148 assert(TNK == TNK_Undeclared_template && "not an undeclared template name");
4150 TemplateName Name = ParsedName.get();
4151 auto *ATN = Name.getAsAssumedTemplateName();
4152 assert(ATN && "not an assumed template name");
4153 II = ATN->getDeclName().getAsIdentifierInfo();
4155 if (!resolveAssumedTemplateNameAsType(S, Name, NameLoc, /*Diagnose*/false)) {
4156 // Resolved to a type template name.
4157 ParsedName = TemplateTy::make(Name);
4158 TNK = TNK_Type_template;
4162 bool Sema::resolveAssumedTemplateNameAsType(Scope *S, TemplateName &Name,
4163 SourceLocation NameLoc,
4164 bool Diagnose) {
4165 // We assumed this undeclared identifier to be an (ADL-only) function
4166 // template name, but it was used in a context where a type was required.
4167 // Try to typo-correct it now.
4168 AssumedTemplateStorage *ATN = Name.getAsAssumedTemplateName();
4169 assert(ATN && "not an assumed template name");
4171 LookupResult R(*this, ATN->getDeclName(), NameLoc, LookupOrdinaryName);
4172 struct CandidateCallback : CorrectionCandidateCallback {
4173 bool ValidateCandidate(const TypoCorrection &TC) override {
4174 return TC.getCorrectionDecl() &&
4175 getAsTypeTemplateDecl(TC.getCorrectionDecl());
4177 std::unique_ptr<CorrectionCandidateCallback> clone() override {
4178 return std::make_unique<CandidateCallback>(*this);
4180 } FilterCCC;
4182 TypoCorrection Corrected =
4183 CorrectTypo(R.getLookupNameInfo(), R.getLookupKind(), S, nullptr,
4184 FilterCCC, CTK_ErrorRecovery);
4185 if (Corrected && Corrected.getFoundDecl()) {
4186 diagnoseTypo(Corrected, PDiag(diag::err_no_template_suggest)
4187 << ATN->getDeclName());
4188 Name = TemplateName(Corrected.getCorrectionDeclAs<TemplateDecl>());
4189 return false;
4192 if (Diagnose)
4193 Diag(R.getNameLoc(), diag::err_no_template) << R.getLookupName();
4194 return true;
4197 TypeResult Sema::ActOnTemplateIdType(
4198 Scope *S, CXXScopeSpec &SS, SourceLocation TemplateKWLoc,
4199 TemplateTy TemplateD, IdentifierInfo *TemplateII,
4200 SourceLocation TemplateIILoc, SourceLocation LAngleLoc,
4201 ASTTemplateArgsPtr TemplateArgsIn, SourceLocation RAngleLoc,
4202 bool IsCtorOrDtorName, bool IsClassName,
4203 ImplicitTypenameContext AllowImplicitTypename) {
4204 if (SS.isInvalid())
4205 return true;
4207 if (!IsCtorOrDtorName && !IsClassName && SS.isSet()) {
4208 DeclContext *LookupCtx = computeDeclContext(SS, /*EnteringContext*/false);
4210 // C++ [temp.res]p3:
4211 // A qualified-id that refers to a type and in which the
4212 // nested-name-specifier depends on a template-parameter (14.6.2)
4213 // shall be prefixed by the keyword typename to indicate that the
4214 // qualified-id denotes a type, forming an
4215 // elaborated-type-specifier (7.1.5.3).
4216 if (!LookupCtx && isDependentScopeSpecifier(SS)) {
4217 // C++2a relaxes some of those restrictions in [temp.res]p5.
4218 if (AllowImplicitTypename == ImplicitTypenameContext::Yes) {
4219 if (getLangOpts().CPlusPlus20)
4220 Diag(SS.getBeginLoc(), diag::warn_cxx17_compat_implicit_typename);
4221 else
4222 Diag(SS.getBeginLoc(), diag::ext_implicit_typename)
4223 << SS.getScopeRep() << TemplateII->getName()
4224 << FixItHint::CreateInsertion(SS.getBeginLoc(), "typename ");
4225 } else
4226 Diag(SS.getBeginLoc(), diag::err_typename_missing_template)
4227 << SS.getScopeRep() << TemplateII->getName();
4229 // FIXME: This is not quite correct recovery as we don't transform SS
4230 // into the corresponding dependent form (and we don't diagnose missing
4231 // 'template' keywords within SS as a result).
4232 return ActOnTypenameType(nullptr, SourceLocation(), SS, TemplateKWLoc,
4233 TemplateD, TemplateII, TemplateIILoc, LAngleLoc,
4234 TemplateArgsIn, RAngleLoc);
4237 // Per C++ [class.qual]p2, if the template-id was an injected-class-name,
4238 // it's not actually allowed to be used as a type in most cases. Because
4239 // we annotate it before we know whether it's valid, we have to check for
4240 // this case here.
4241 auto *LookupRD = dyn_cast_or_null<CXXRecordDecl>(LookupCtx);
4242 if (LookupRD && LookupRD->getIdentifier() == TemplateII) {
4243 Diag(TemplateIILoc,
4244 TemplateKWLoc.isInvalid()
4245 ? diag::err_out_of_line_qualified_id_type_names_constructor
4246 : diag::ext_out_of_line_qualified_id_type_names_constructor)
4247 << TemplateII << 0 /*injected-class-name used as template name*/
4248 << 1 /*if any keyword was present, it was 'template'*/;
4252 TemplateName Template = TemplateD.get();
4253 if (Template.getAsAssumedTemplateName() &&
4254 resolveAssumedTemplateNameAsType(S, Template, TemplateIILoc))
4255 return true;
4257 // Translate the parser's template argument list in our AST format.
4258 TemplateArgumentListInfo TemplateArgs(LAngleLoc, RAngleLoc);
4259 translateTemplateArguments(TemplateArgsIn, TemplateArgs);
4261 if (DependentTemplateName *DTN = Template.getAsDependentTemplateName()) {
4262 assert(SS.getScopeRep() == DTN->getQualifier());
4263 QualType T = Context.getDependentTemplateSpecializationType(
4264 ElaboratedTypeKeyword::None, DTN->getQualifier(), DTN->getIdentifier(),
4265 TemplateArgs.arguments());
4266 // Build type-source information.
4267 TypeLocBuilder TLB;
4268 DependentTemplateSpecializationTypeLoc SpecTL
4269 = TLB.push<DependentTemplateSpecializationTypeLoc>(T);
4270 SpecTL.setElaboratedKeywordLoc(SourceLocation());
4271 SpecTL.setQualifierLoc(SS.getWithLocInContext(Context));
4272 SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
4273 SpecTL.setTemplateNameLoc(TemplateIILoc);
4274 SpecTL.setLAngleLoc(LAngleLoc);
4275 SpecTL.setRAngleLoc(RAngleLoc);
4276 for (unsigned I = 0, N = SpecTL.getNumArgs(); I != N; ++I)
4277 SpecTL.setArgLocInfo(I, TemplateArgs[I].getLocInfo());
4278 return CreateParsedType(T, TLB.getTypeSourceInfo(Context, T));
4281 QualType SpecTy = CheckTemplateIdType(Template, TemplateIILoc, TemplateArgs);
4282 if (SpecTy.isNull())
4283 return true;
4285 // Build type-source information.
4286 TypeLocBuilder TLB;
4287 TemplateSpecializationTypeLoc SpecTL =
4288 TLB.push<TemplateSpecializationTypeLoc>(SpecTy);
4289 SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
4290 SpecTL.setTemplateNameLoc(TemplateIILoc);
4291 SpecTL.setLAngleLoc(LAngleLoc);
4292 SpecTL.setRAngleLoc(RAngleLoc);
4293 for (unsigned i = 0, e = SpecTL.getNumArgs(); i != e; ++i)
4294 SpecTL.setArgLocInfo(i, TemplateArgs[i].getLocInfo());
4296 // Create an elaborated-type-specifier containing the nested-name-specifier.
4297 QualType ElTy =
4298 getElaboratedType(ElaboratedTypeKeyword::None,
4299 !IsCtorOrDtorName ? SS : CXXScopeSpec(), SpecTy);
4300 ElaboratedTypeLoc ElabTL = TLB.push<ElaboratedTypeLoc>(ElTy);
4301 ElabTL.setElaboratedKeywordLoc(SourceLocation());
4302 if (!ElabTL.isEmpty())
4303 ElabTL.setQualifierLoc(SS.getWithLocInContext(Context));
4304 return CreateParsedType(ElTy, TLB.getTypeSourceInfo(Context, ElTy));
4307 TypeResult Sema::ActOnTagTemplateIdType(TagUseKind TUK,
4308 TypeSpecifierType TagSpec,
4309 SourceLocation TagLoc,
4310 CXXScopeSpec &SS,
4311 SourceLocation TemplateKWLoc,
4312 TemplateTy TemplateD,
4313 SourceLocation TemplateLoc,
4314 SourceLocation LAngleLoc,
4315 ASTTemplateArgsPtr TemplateArgsIn,
4316 SourceLocation RAngleLoc) {
4317 if (SS.isInvalid())
4318 return TypeResult(true);
4320 TemplateName Template = TemplateD.get();
4322 // Translate the parser's template argument list in our AST format.
4323 TemplateArgumentListInfo TemplateArgs(LAngleLoc, RAngleLoc);
4324 translateTemplateArguments(TemplateArgsIn, TemplateArgs);
4326 // Determine the tag kind
4327 TagTypeKind TagKind = TypeWithKeyword::getTagTypeKindForTypeSpec(TagSpec);
4328 ElaboratedTypeKeyword Keyword
4329 = TypeWithKeyword::getKeywordForTagTypeKind(TagKind);
4331 if (DependentTemplateName *DTN = Template.getAsDependentTemplateName()) {
4332 assert(SS.getScopeRep() == DTN->getQualifier());
4333 QualType T = Context.getDependentTemplateSpecializationType(
4334 Keyword, DTN->getQualifier(), DTN->getIdentifier(),
4335 TemplateArgs.arguments());
4337 // Build type-source information.
4338 TypeLocBuilder TLB;
4339 DependentTemplateSpecializationTypeLoc SpecTL
4340 = TLB.push<DependentTemplateSpecializationTypeLoc>(T);
4341 SpecTL.setElaboratedKeywordLoc(TagLoc);
4342 SpecTL.setQualifierLoc(SS.getWithLocInContext(Context));
4343 SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
4344 SpecTL.setTemplateNameLoc(TemplateLoc);
4345 SpecTL.setLAngleLoc(LAngleLoc);
4346 SpecTL.setRAngleLoc(RAngleLoc);
4347 for (unsigned I = 0, N = SpecTL.getNumArgs(); I != N; ++I)
4348 SpecTL.setArgLocInfo(I, TemplateArgs[I].getLocInfo());
4349 return CreateParsedType(T, TLB.getTypeSourceInfo(Context, T));
4352 if (TypeAliasTemplateDecl *TAT =
4353 dyn_cast_or_null<TypeAliasTemplateDecl>(Template.getAsTemplateDecl())) {
4354 // C++0x [dcl.type.elab]p2:
4355 // If the identifier resolves to a typedef-name or the simple-template-id
4356 // resolves to an alias template specialization, the
4357 // elaborated-type-specifier is ill-formed.
4358 Diag(TemplateLoc, diag::err_tag_reference_non_tag)
4359 << TAT << NTK_TypeAliasTemplate << llvm::to_underlying(TagKind);
4360 Diag(TAT->getLocation(), diag::note_declared_at);
4363 QualType Result = CheckTemplateIdType(Template, TemplateLoc, TemplateArgs);
4364 if (Result.isNull())
4365 return TypeResult(true);
4367 // Check the tag kind
4368 if (const RecordType *RT = Result->getAs<RecordType>()) {
4369 RecordDecl *D = RT->getDecl();
4371 IdentifierInfo *Id = D->getIdentifier();
4372 assert(Id && "templated class must have an identifier");
4374 if (!isAcceptableTagRedeclaration(D, TagKind, TUK == TUK_Definition,
4375 TagLoc, Id)) {
4376 Diag(TagLoc, diag::err_use_with_wrong_tag)
4377 << Result
4378 << FixItHint::CreateReplacement(SourceRange(TagLoc), D->getKindName());
4379 Diag(D->getLocation(), diag::note_previous_use);
4383 // Provide source-location information for the template specialization.
4384 TypeLocBuilder TLB;
4385 TemplateSpecializationTypeLoc SpecTL
4386 = TLB.push<TemplateSpecializationTypeLoc>(Result);
4387 SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
4388 SpecTL.setTemplateNameLoc(TemplateLoc);
4389 SpecTL.setLAngleLoc(LAngleLoc);
4390 SpecTL.setRAngleLoc(RAngleLoc);
4391 for (unsigned i = 0, e = SpecTL.getNumArgs(); i != e; ++i)
4392 SpecTL.setArgLocInfo(i, TemplateArgs[i].getLocInfo());
4394 // Construct an elaborated type containing the nested-name-specifier (if any)
4395 // and tag keyword.
4396 Result = Context.getElaboratedType(Keyword, SS.getScopeRep(), Result);
4397 ElaboratedTypeLoc ElabTL = TLB.push<ElaboratedTypeLoc>(Result);
4398 ElabTL.setElaboratedKeywordLoc(TagLoc);
4399 ElabTL.setQualifierLoc(SS.getWithLocInContext(Context));
4400 return CreateParsedType(Result, TLB.getTypeSourceInfo(Context, Result));
4403 static bool CheckTemplateSpecializationScope(Sema &S, NamedDecl *Specialized,
4404 NamedDecl *PrevDecl,
4405 SourceLocation Loc,
4406 bool IsPartialSpecialization);
4408 static TemplateSpecializationKind getTemplateSpecializationKind(Decl *D);
4410 static bool isTemplateArgumentTemplateParameter(
4411 const TemplateArgument &Arg, unsigned Depth, unsigned Index) {
4412 switch (Arg.getKind()) {
4413 case TemplateArgument::Null:
4414 case TemplateArgument::NullPtr:
4415 case TemplateArgument::Integral:
4416 case TemplateArgument::Declaration:
4417 case TemplateArgument::Pack:
4418 case TemplateArgument::TemplateExpansion:
4419 return false;
4421 case TemplateArgument::Type: {
4422 QualType Type = Arg.getAsType();
4423 const TemplateTypeParmType *TPT =
4424 Arg.getAsType()->getAs<TemplateTypeParmType>();
4425 return TPT && !Type.hasQualifiers() &&
4426 TPT->getDepth() == Depth && TPT->getIndex() == Index;
4429 case TemplateArgument::Expression: {
4430 DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Arg.getAsExpr());
4431 if (!DRE || !DRE->getDecl())
4432 return false;
4433 const NonTypeTemplateParmDecl *NTTP =
4434 dyn_cast<NonTypeTemplateParmDecl>(DRE->getDecl());
4435 return NTTP && NTTP->getDepth() == Depth && NTTP->getIndex() == Index;
4438 case TemplateArgument::Template:
4439 const TemplateTemplateParmDecl *TTP =
4440 dyn_cast_or_null<TemplateTemplateParmDecl>(
4441 Arg.getAsTemplateOrTemplatePattern().getAsTemplateDecl());
4442 return TTP && TTP->getDepth() == Depth && TTP->getIndex() == Index;
4444 llvm_unreachable("unexpected kind of template argument");
4447 static bool isSameAsPrimaryTemplate(TemplateParameterList *Params,
4448 ArrayRef<TemplateArgument> Args) {
4449 if (Params->size() != Args.size())
4450 return false;
4452 unsigned Depth = Params->getDepth();
4454 for (unsigned I = 0, N = Args.size(); I != N; ++I) {
4455 TemplateArgument Arg = Args[I];
4457 // If the parameter is a pack expansion, the argument must be a pack
4458 // whose only element is a pack expansion.
4459 if (Params->getParam(I)->isParameterPack()) {
4460 if (Arg.getKind() != TemplateArgument::Pack || Arg.pack_size() != 1 ||
4461 !Arg.pack_begin()->isPackExpansion())
4462 return false;
4463 Arg = Arg.pack_begin()->getPackExpansionPattern();
4466 if (!isTemplateArgumentTemplateParameter(Arg, Depth, I))
4467 return false;
4470 return true;
4473 template<typename PartialSpecDecl>
4474 static void checkMoreSpecializedThanPrimary(Sema &S, PartialSpecDecl *Partial) {
4475 if (Partial->getDeclContext()->isDependentContext())
4476 return;
4478 // FIXME: Get the TDK from deduction in order to provide better diagnostics
4479 // for non-substitution-failure issues?
4480 TemplateDeductionInfo Info(Partial->getLocation());
4481 if (S.isMoreSpecializedThanPrimary(Partial, Info))
4482 return;
4484 auto *Template = Partial->getSpecializedTemplate();
4485 S.Diag(Partial->getLocation(),
4486 diag::ext_partial_spec_not_more_specialized_than_primary)
4487 << isa<VarTemplateDecl>(Template);
4489 if (Info.hasSFINAEDiagnostic()) {
4490 PartialDiagnosticAt Diag = {SourceLocation(),
4491 PartialDiagnostic::NullDiagnostic()};
4492 Info.takeSFINAEDiagnostic(Diag);
4493 SmallString<128> SFINAEArgString;
4494 Diag.second.EmitToString(S.getDiagnostics(), SFINAEArgString);
4495 S.Diag(Diag.first,
4496 diag::note_partial_spec_not_more_specialized_than_primary)
4497 << SFINAEArgString;
4500 S.NoteTemplateLocation(*Template);
4501 SmallVector<const Expr *, 3> PartialAC, TemplateAC;
4502 Template->getAssociatedConstraints(TemplateAC);
4503 Partial->getAssociatedConstraints(PartialAC);
4504 S.MaybeEmitAmbiguousAtomicConstraintsDiagnostic(Partial, PartialAC, Template,
4505 TemplateAC);
4508 static void
4509 noteNonDeducibleParameters(Sema &S, TemplateParameterList *TemplateParams,
4510 const llvm::SmallBitVector &DeducibleParams) {
4511 for (unsigned I = 0, N = DeducibleParams.size(); I != N; ++I) {
4512 if (!DeducibleParams[I]) {
4513 NamedDecl *Param = TemplateParams->getParam(I);
4514 if (Param->getDeclName())
4515 S.Diag(Param->getLocation(), diag::note_non_deducible_parameter)
4516 << Param->getDeclName();
4517 else
4518 S.Diag(Param->getLocation(), diag::note_non_deducible_parameter)
4519 << "(anonymous)";
4525 template<typename PartialSpecDecl>
4526 static void checkTemplatePartialSpecialization(Sema &S,
4527 PartialSpecDecl *Partial) {
4528 // C++1z [temp.class.spec]p8: (DR1495)
4529 // - The specialization shall be more specialized than the primary
4530 // template (14.5.5.2).
4531 checkMoreSpecializedThanPrimary(S, Partial);
4533 // C++ [temp.class.spec]p8: (DR1315)
4534 // - Each template-parameter shall appear at least once in the
4535 // template-id outside a non-deduced context.
4536 // C++1z [temp.class.spec.match]p3 (P0127R2)
4537 // If the template arguments of a partial specialization cannot be
4538 // deduced because of the structure of its template-parameter-list
4539 // and the template-id, the program is ill-formed.
4540 auto *TemplateParams = Partial->getTemplateParameters();
4541 llvm::SmallBitVector DeducibleParams(TemplateParams->size());
4542 S.MarkUsedTemplateParameters(Partial->getTemplateArgs(), true,
4543 TemplateParams->getDepth(), DeducibleParams);
4545 if (!DeducibleParams.all()) {
4546 unsigned NumNonDeducible = DeducibleParams.size() - DeducibleParams.count();
4547 S.Diag(Partial->getLocation(), diag::ext_partial_specs_not_deducible)
4548 << isa<VarTemplatePartialSpecializationDecl>(Partial)
4549 << (NumNonDeducible > 1)
4550 << SourceRange(Partial->getLocation(),
4551 Partial->getTemplateArgsAsWritten()->RAngleLoc);
4552 noteNonDeducibleParameters(S, TemplateParams, DeducibleParams);
4556 void Sema::CheckTemplatePartialSpecialization(
4557 ClassTemplatePartialSpecializationDecl *Partial) {
4558 checkTemplatePartialSpecialization(*this, Partial);
4561 void Sema::CheckTemplatePartialSpecialization(
4562 VarTemplatePartialSpecializationDecl *Partial) {
4563 checkTemplatePartialSpecialization(*this, Partial);
4566 void Sema::CheckDeductionGuideTemplate(FunctionTemplateDecl *TD) {
4567 // C++1z [temp.param]p11:
4568 // A template parameter of a deduction guide template that does not have a
4569 // default-argument shall be deducible from the parameter-type-list of the
4570 // deduction guide template.
4571 auto *TemplateParams = TD->getTemplateParameters();
4572 llvm::SmallBitVector DeducibleParams(TemplateParams->size());
4573 MarkDeducedTemplateParameters(TD, DeducibleParams);
4574 for (unsigned I = 0; I != TemplateParams->size(); ++I) {
4575 // A parameter pack is deducible (to an empty pack).
4576 auto *Param = TemplateParams->getParam(I);
4577 if (Param->isParameterPack() || hasVisibleDefaultArgument(Param))
4578 DeducibleParams[I] = true;
4581 if (!DeducibleParams.all()) {
4582 unsigned NumNonDeducible = DeducibleParams.size() - DeducibleParams.count();
4583 Diag(TD->getLocation(), diag::err_deduction_guide_template_not_deducible)
4584 << (NumNonDeducible > 1);
4585 noteNonDeducibleParameters(*this, TemplateParams, DeducibleParams);
4589 DeclResult Sema::ActOnVarTemplateSpecialization(
4590 Scope *S, Declarator &D, TypeSourceInfo *DI, SourceLocation TemplateKWLoc,
4591 TemplateParameterList *TemplateParams, StorageClass SC,
4592 bool IsPartialSpecialization) {
4593 // D must be variable template id.
4594 assert(D.getName().getKind() == UnqualifiedIdKind::IK_TemplateId &&
4595 "Variable template specialization is declared with a template id.");
4597 TemplateIdAnnotation *TemplateId = D.getName().TemplateId;
4598 TemplateArgumentListInfo TemplateArgs =
4599 makeTemplateArgumentListInfo(*this, *TemplateId);
4600 SourceLocation TemplateNameLoc = D.getIdentifierLoc();
4601 SourceLocation LAngleLoc = TemplateId->LAngleLoc;
4602 SourceLocation RAngleLoc = TemplateId->RAngleLoc;
4604 TemplateName Name = TemplateId->Template.get();
4606 // The template-id must name a variable template.
4607 VarTemplateDecl *VarTemplate =
4608 dyn_cast_or_null<VarTemplateDecl>(Name.getAsTemplateDecl());
4609 if (!VarTemplate) {
4610 NamedDecl *FnTemplate;
4611 if (auto *OTS = Name.getAsOverloadedTemplate())
4612 FnTemplate = *OTS->begin();
4613 else
4614 FnTemplate = dyn_cast_or_null<FunctionTemplateDecl>(Name.getAsTemplateDecl());
4615 if (FnTemplate)
4616 return Diag(D.getIdentifierLoc(), diag::err_var_spec_no_template_but_method)
4617 << FnTemplate->getDeclName();
4618 return Diag(D.getIdentifierLoc(), diag::err_var_spec_no_template)
4619 << IsPartialSpecialization;
4622 // Check for unexpanded parameter packs in any of the template arguments.
4623 for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I)
4624 if (DiagnoseUnexpandedParameterPack(TemplateArgs[I],
4625 IsPartialSpecialization
4626 ? UPPC_PartialSpecialization
4627 : UPPC_ExplicitSpecialization))
4628 return true;
4630 // Check that the template argument list is well-formed for this
4631 // template.
4632 SmallVector<TemplateArgument, 4> SugaredConverted, CanonicalConverted;
4633 if (CheckTemplateArgumentList(VarTemplate, TemplateNameLoc, TemplateArgs,
4634 false, SugaredConverted, CanonicalConverted,
4635 /*UpdateArgsWithConversions=*/true))
4636 return true;
4638 // Find the variable template (partial) specialization declaration that
4639 // corresponds to these arguments.
4640 if (IsPartialSpecialization) {
4641 if (CheckTemplatePartialSpecializationArgs(TemplateNameLoc, VarTemplate,
4642 TemplateArgs.size(),
4643 CanonicalConverted))
4644 return true;
4646 // FIXME: Move these checks to CheckTemplatePartialSpecializationArgs so we
4647 // also do them during instantiation.
4648 if (!Name.isDependent() &&
4649 !TemplateSpecializationType::anyDependentTemplateArguments(
4650 TemplateArgs, CanonicalConverted)) {
4651 Diag(TemplateNameLoc, diag::err_partial_spec_fully_specialized)
4652 << VarTemplate->getDeclName();
4653 IsPartialSpecialization = false;
4656 if (isSameAsPrimaryTemplate(VarTemplate->getTemplateParameters(),
4657 CanonicalConverted) &&
4658 (!Context.getLangOpts().CPlusPlus20 ||
4659 !TemplateParams->hasAssociatedConstraints())) {
4660 // C++ [temp.class.spec]p9b3:
4662 // -- The argument list of the specialization shall not be identical
4663 // to the implicit argument list of the primary template.
4664 Diag(TemplateNameLoc, diag::err_partial_spec_args_match_primary_template)
4665 << /*variable template*/ 1
4666 << /*is definition*/(SC != SC_Extern && !CurContext->isRecord())
4667 << FixItHint::CreateRemoval(SourceRange(LAngleLoc, RAngleLoc));
4668 // FIXME: Recover from this by treating the declaration as a redeclaration
4669 // of the primary template.
4670 return true;
4674 void *InsertPos = nullptr;
4675 VarTemplateSpecializationDecl *PrevDecl = nullptr;
4677 if (IsPartialSpecialization)
4678 PrevDecl = VarTemplate->findPartialSpecialization(
4679 CanonicalConverted, TemplateParams, InsertPos);
4680 else
4681 PrevDecl = VarTemplate->findSpecialization(CanonicalConverted, InsertPos);
4683 VarTemplateSpecializationDecl *Specialization = nullptr;
4685 // Check whether we can declare a variable template specialization in
4686 // the current scope.
4687 if (CheckTemplateSpecializationScope(*this, VarTemplate, PrevDecl,
4688 TemplateNameLoc,
4689 IsPartialSpecialization))
4690 return true;
4692 if (PrevDecl && PrevDecl->getSpecializationKind() == TSK_Undeclared) {
4693 // Since the only prior variable template specialization with these
4694 // arguments was referenced but not declared, reuse that
4695 // declaration node as our own, updating its source location and
4696 // the list of outer template parameters to reflect our new declaration.
4697 Specialization = PrevDecl;
4698 Specialization->setLocation(TemplateNameLoc);
4699 PrevDecl = nullptr;
4700 } else if (IsPartialSpecialization) {
4701 // Create a new class template partial specialization declaration node.
4702 VarTemplatePartialSpecializationDecl *PrevPartial =
4703 cast_or_null<VarTemplatePartialSpecializationDecl>(PrevDecl);
4704 VarTemplatePartialSpecializationDecl *Partial =
4705 VarTemplatePartialSpecializationDecl::Create(
4706 Context, VarTemplate->getDeclContext(), TemplateKWLoc,
4707 TemplateNameLoc, TemplateParams, VarTemplate, DI->getType(), DI, SC,
4708 CanonicalConverted, TemplateArgs);
4710 if (!PrevPartial)
4711 VarTemplate->AddPartialSpecialization(Partial, InsertPos);
4712 Specialization = Partial;
4714 // If we are providing an explicit specialization of a member variable
4715 // template specialization, make a note of that.
4716 if (PrevPartial && PrevPartial->getInstantiatedFromMember())
4717 PrevPartial->setMemberSpecialization();
4719 CheckTemplatePartialSpecialization(Partial);
4720 } else {
4721 // Create a new class template specialization declaration node for
4722 // this explicit specialization or friend declaration.
4723 Specialization = VarTemplateSpecializationDecl::Create(
4724 Context, VarTemplate->getDeclContext(), TemplateKWLoc, TemplateNameLoc,
4725 VarTemplate, DI->getType(), DI, SC, CanonicalConverted);
4726 Specialization->setTemplateArgsInfo(TemplateArgs);
4728 if (!PrevDecl)
4729 VarTemplate->AddSpecialization(Specialization, InsertPos);
4732 // C++ [temp.expl.spec]p6:
4733 // If a template, a member template or the member of a class template is
4734 // explicitly specialized then that specialization shall be declared
4735 // before the first use of that specialization that would cause an implicit
4736 // instantiation to take place, in every translation unit in which such a
4737 // use occurs; no diagnostic is required.
4738 if (PrevDecl && PrevDecl->getPointOfInstantiation().isValid()) {
4739 bool Okay = false;
4740 for (Decl *Prev = PrevDecl; Prev; Prev = Prev->getPreviousDecl()) {
4741 // Is there any previous explicit specialization declaration?
4742 if (getTemplateSpecializationKind(Prev) == TSK_ExplicitSpecialization) {
4743 Okay = true;
4744 break;
4748 if (!Okay) {
4749 SourceRange Range(TemplateNameLoc, RAngleLoc);
4750 Diag(TemplateNameLoc, diag::err_specialization_after_instantiation)
4751 << Name << Range;
4753 Diag(PrevDecl->getPointOfInstantiation(),
4754 diag::note_instantiation_required_here)
4755 << (PrevDecl->getTemplateSpecializationKind() !=
4756 TSK_ImplicitInstantiation);
4757 return true;
4761 Specialization->setTemplateKeywordLoc(TemplateKWLoc);
4762 Specialization->setLexicalDeclContext(CurContext);
4764 // Add the specialization into its lexical context, so that it can
4765 // be seen when iterating through the list of declarations in that
4766 // context. However, specializations are not found by name lookup.
4767 CurContext->addDecl(Specialization);
4769 // Note that this is an explicit specialization.
4770 Specialization->setSpecializationKind(TSK_ExplicitSpecialization);
4772 if (PrevDecl) {
4773 // Check that this isn't a redefinition of this specialization,
4774 // merging with previous declarations.
4775 LookupResult PrevSpec(*this, GetNameForDeclarator(D), LookupOrdinaryName,
4776 forRedeclarationInCurContext());
4777 PrevSpec.addDecl(PrevDecl);
4778 D.setRedeclaration(CheckVariableDeclaration(Specialization, PrevSpec));
4779 } else if (Specialization->isStaticDataMember() &&
4780 Specialization->isOutOfLine()) {
4781 Specialization->setAccess(VarTemplate->getAccess());
4784 return Specialization;
4787 namespace {
4788 /// A partial specialization whose template arguments have matched
4789 /// a given template-id.
4790 struct PartialSpecMatchResult {
4791 VarTemplatePartialSpecializationDecl *Partial;
4792 TemplateArgumentList *Args;
4794 } // end anonymous namespace
4796 DeclResult
4797 Sema::CheckVarTemplateId(VarTemplateDecl *Template, SourceLocation TemplateLoc,
4798 SourceLocation TemplateNameLoc,
4799 const TemplateArgumentListInfo &TemplateArgs) {
4800 assert(Template && "A variable template id without template?");
4802 // Check that the template argument list is well-formed for this template.
4803 SmallVector<TemplateArgument, 4> SugaredConverted, CanonicalConverted;
4804 if (CheckTemplateArgumentList(
4805 Template, TemplateNameLoc,
4806 const_cast<TemplateArgumentListInfo &>(TemplateArgs), false,
4807 SugaredConverted, CanonicalConverted,
4808 /*UpdateArgsWithConversions=*/true))
4809 return true;
4811 // Produce a placeholder value if the specialization is dependent.
4812 if (Template->getDeclContext()->isDependentContext() ||
4813 TemplateSpecializationType::anyDependentTemplateArguments(
4814 TemplateArgs, CanonicalConverted))
4815 return DeclResult();
4817 // Find the variable template specialization declaration that
4818 // corresponds to these arguments.
4819 void *InsertPos = nullptr;
4820 if (VarTemplateSpecializationDecl *Spec =
4821 Template->findSpecialization(CanonicalConverted, InsertPos)) {
4822 checkSpecializationReachability(TemplateNameLoc, Spec);
4823 // If we already have a variable template specialization, return it.
4824 return Spec;
4827 // This is the first time we have referenced this variable template
4828 // specialization. Create the canonical declaration and add it to
4829 // the set of specializations, based on the closest partial specialization
4830 // that it represents. That is,
4831 VarDecl *InstantiationPattern = Template->getTemplatedDecl();
4832 TemplateArgumentList TemplateArgList(TemplateArgumentList::OnStack,
4833 CanonicalConverted);
4834 TemplateArgumentList *InstantiationArgs = &TemplateArgList;
4835 bool AmbiguousPartialSpec = false;
4836 typedef PartialSpecMatchResult MatchResult;
4837 SmallVector<MatchResult, 4> Matched;
4838 SourceLocation PointOfInstantiation = TemplateNameLoc;
4839 TemplateSpecCandidateSet FailedCandidates(PointOfInstantiation,
4840 /*ForTakingAddress=*/false);
4842 // 1. Attempt to find the closest partial specialization that this
4843 // specializes, if any.
4844 // TODO: Unify with InstantiateClassTemplateSpecialization()?
4845 // Perhaps better after unification of DeduceTemplateArguments() and
4846 // getMoreSpecializedPartialSpecialization().
4847 SmallVector<VarTemplatePartialSpecializationDecl *, 4> PartialSpecs;
4848 Template->getPartialSpecializations(PartialSpecs);
4850 for (unsigned I = 0, N = PartialSpecs.size(); I != N; ++I) {
4851 VarTemplatePartialSpecializationDecl *Partial = PartialSpecs[I];
4852 TemplateDeductionInfo Info(FailedCandidates.getLocation());
4854 if (TemplateDeductionResult Result =
4855 DeduceTemplateArguments(Partial, TemplateArgList, Info)) {
4856 // Store the failed-deduction information for use in diagnostics, later.
4857 // TODO: Actually use the failed-deduction info?
4858 FailedCandidates.addCandidate().set(
4859 DeclAccessPair::make(Template, AS_public), Partial,
4860 MakeDeductionFailureInfo(Context, Result, Info));
4861 (void)Result;
4862 } else {
4863 Matched.push_back(PartialSpecMatchResult());
4864 Matched.back().Partial = Partial;
4865 Matched.back().Args = Info.takeCanonical();
4869 if (Matched.size() >= 1) {
4870 SmallVector<MatchResult, 4>::iterator Best = Matched.begin();
4871 if (Matched.size() == 1) {
4872 // -- If exactly one matching specialization is found, the
4873 // instantiation is generated from that specialization.
4874 // We don't need to do anything for this.
4875 } else {
4876 // -- If more than one matching specialization is found, the
4877 // partial order rules (14.5.4.2) are used to determine
4878 // whether one of the specializations is more specialized
4879 // than the others. If none of the specializations is more
4880 // specialized than all of the other matching
4881 // specializations, then the use of the variable template is
4882 // ambiguous and the program is ill-formed.
4883 for (SmallVector<MatchResult, 4>::iterator P = Best + 1,
4884 PEnd = Matched.end();
4885 P != PEnd; ++P) {
4886 if (getMoreSpecializedPartialSpecialization(P->Partial, Best->Partial,
4887 PointOfInstantiation) ==
4888 P->Partial)
4889 Best = P;
4892 // Determine if the best partial specialization is more specialized than
4893 // the others.
4894 for (SmallVector<MatchResult, 4>::iterator P = Matched.begin(),
4895 PEnd = Matched.end();
4896 P != PEnd; ++P) {
4897 if (P != Best && getMoreSpecializedPartialSpecialization(
4898 P->Partial, Best->Partial,
4899 PointOfInstantiation) != Best->Partial) {
4900 AmbiguousPartialSpec = true;
4901 break;
4906 // Instantiate using the best variable template partial specialization.
4907 InstantiationPattern = Best->Partial;
4908 InstantiationArgs = Best->Args;
4909 } else {
4910 // -- If no match is found, the instantiation is generated
4911 // from the primary template.
4912 // InstantiationPattern = Template->getTemplatedDecl();
4915 // 2. Create the canonical declaration.
4916 // Note that we do not instantiate a definition until we see an odr-use
4917 // in DoMarkVarDeclReferenced().
4918 // FIXME: LateAttrs et al.?
4919 VarTemplateSpecializationDecl *Decl = BuildVarTemplateInstantiation(
4920 Template, InstantiationPattern, *InstantiationArgs, TemplateArgs,
4921 CanonicalConverted, TemplateNameLoc /*, LateAttrs, StartingScope*/);
4922 if (!Decl)
4923 return true;
4925 if (AmbiguousPartialSpec) {
4926 // Partial ordering did not produce a clear winner. Complain.
4927 Decl->setInvalidDecl();
4928 Diag(PointOfInstantiation, diag::err_partial_spec_ordering_ambiguous)
4929 << Decl;
4931 // Print the matching partial specializations.
4932 for (MatchResult P : Matched)
4933 Diag(P.Partial->getLocation(), diag::note_partial_spec_match)
4934 << getTemplateArgumentBindingsText(P.Partial->getTemplateParameters(),
4935 *P.Args);
4936 return true;
4939 if (VarTemplatePartialSpecializationDecl *D =
4940 dyn_cast<VarTemplatePartialSpecializationDecl>(InstantiationPattern))
4941 Decl->setInstantiationOf(D, InstantiationArgs);
4943 checkSpecializationReachability(TemplateNameLoc, Decl);
4945 assert(Decl && "No variable template specialization?");
4946 return Decl;
4949 ExprResult
4950 Sema::CheckVarTemplateId(const CXXScopeSpec &SS,
4951 const DeclarationNameInfo &NameInfo,
4952 VarTemplateDecl *Template, SourceLocation TemplateLoc,
4953 const TemplateArgumentListInfo *TemplateArgs) {
4955 DeclResult Decl = CheckVarTemplateId(Template, TemplateLoc, NameInfo.getLoc(),
4956 *TemplateArgs);
4957 if (Decl.isInvalid())
4958 return ExprError();
4960 if (!Decl.get())
4961 return ExprResult();
4963 VarDecl *Var = cast<VarDecl>(Decl.get());
4964 if (!Var->getTemplateSpecializationKind())
4965 Var->setTemplateSpecializationKind(TSK_ImplicitInstantiation,
4966 NameInfo.getLoc());
4968 // Build an ordinary singleton decl ref.
4969 return BuildDeclarationNameExpr(SS, NameInfo, Var,
4970 /*FoundD=*/nullptr, TemplateArgs);
4973 void Sema::diagnoseMissingTemplateArguments(TemplateName Name,
4974 SourceLocation Loc) {
4975 Diag(Loc, diag::err_template_missing_args)
4976 << (int)getTemplateNameKindForDiagnostics(Name) << Name;
4977 if (TemplateDecl *TD = Name.getAsTemplateDecl()) {
4978 NoteTemplateLocation(*TD, TD->getTemplateParameters()->getSourceRange());
4982 ExprResult
4983 Sema::CheckConceptTemplateId(const CXXScopeSpec &SS,
4984 SourceLocation TemplateKWLoc,
4985 const DeclarationNameInfo &ConceptNameInfo,
4986 NamedDecl *FoundDecl,
4987 ConceptDecl *NamedConcept,
4988 const TemplateArgumentListInfo *TemplateArgs) {
4989 assert(NamedConcept && "A concept template id without a template?");
4991 llvm::SmallVector<TemplateArgument, 4> SugaredConverted, CanonicalConverted;
4992 if (CheckTemplateArgumentList(
4993 NamedConcept, ConceptNameInfo.getLoc(),
4994 const_cast<TemplateArgumentListInfo &>(*TemplateArgs),
4995 /*PartialTemplateArgs=*/false, SugaredConverted, CanonicalConverted,
4996 /*UpdateArgsWithConversions=*/false))
4997 return ExprError();
4999 auto *CSD = ImplicitConceptSpecializationDecl::Create(
5000 Context, NamedConcept->getDeclContext(), NamedConcept->getLocation(),
5001 CanonicalConverted);
5002 ConstraintSatisfaction Satisfaction;
5003 bool AreArgsDependent =
5004 TemplateSpecializationType::anyDependentTemplateArguments(
5005 *TemplateArgs, CanonicalConverted);
5006 MultiLevelTemplateArgumentList MLTAL(NamedConcept, CanonicalConverted,
5007 /*Final=*/false);
5008 LocalInstantiationScope Scope(*this);
5010 EnterExpressionEvaluationContext EECtx{
5011 *this, ExpressionEvaluationContext::ConstantEvaluated, CSD};
5013 if (!AreArgsDependent &&
5014 CheckConstraintSatisfaction(
5015 NamedConcept, {NamedConcept->getConstraintExpr()}, MLTAL,
5016 SourceRange(SS.isSet() ? SS.getBeginLoc() : ConceptNameInfo.getLoc(),
5017 TemplateArgs->getRAngleLoc()),
5018 Satisfaction))
5019 return ExprError();
5020 auto *CL = ConceptReference::Create(
5021 Context,
5022 SS.isSet() ? SS.getWithLocInContext(Context) : NestedNameSpecifierLoc{},
5023 TemplateKWLoc, ConceptNameInfo, FoundDecl, NamedConcept,
5024 ASTTemplateArgumentListInfo::Create(Context, *TemplateArgs));
5025 return ConceptSpecializationExpr::Create(
5026 Context, CL, CSD, AreArgsDependent ? nullptr : &Satisfaction);
5029 ExprResult Sema::BuildTemplateIdExpr(const CXXScopeSpec &SS,
5030 SourceLocation TemplateKWLoc,
5031 LookupResult &R,
5032 bool RequiresADL,
5033 const TemplateArgumentListInfo *TemplateArgs) {
5034 // FIXME: Can we do any checking at this point? I guess we could check the
5035 // template arguments that we have against the template name, if the template
5036 // name refers to a single template. That's not a terribly common case,
5037 // though.
5038 // foo<int> could identify a single function unambiguously
5039 // This approach does NOT work, since f<int>(1);
5040 // gets resolved prior to resorting to overload resolution
5041 // i.e., template<class T> void f(double);
5042 // vs template<class T, class U> void f(U);
5044 // These should be filtered out by our callers.
5045 assert(!R.isAmbiguous() && "ambiguous lookup when building templateid");
5047 // Non-function templates require a template argument list.
5048 if (auto *TD = R.getAsSingle<TemplateDecl>()) {
5049 if (!TemplateArgs && !isa<FunctionTemplateDecl>(TD)) {
5050 diagnoseMissingTemplateArguments(TemplateName(TD), R.getNameLoc());
5051 return ExprError();
5054 bool KnownDependent = false;
5055 // In C++1y, check variable template ids.
5056 if (R.getAsSingle<VarTemplateDecl>()) {
5057 ExprResult Res = CheckVarTemplateId(SS, R.getLookupNameInfo(),
5058 R.getAsSingle<VarTemplateDecl>(),
5059 TemplateKWLoc, TemplateArgs);
5060 if (Res.isInvalid() || Res.isUsable())
5061 return Res;
5062 // Result is dependent. Carry on to build an UnresolvedLookupEpxr.
5063 KnownDependent = true;
5066 if (R.getAsSingle<ConceptDecl>()) {
5067 return CheckConceptTemplateId(SS, TemplateKWLoc, R.getLookupNameInfo(),
5068 R.getFoundDecl(),
5069 R.getAsSingle<ConceptDecl>(), TemplateArgs);
5072 // We don't want lookup warnings at this point.
5073 R.suppressDiagnostics();
5075 UnresolvedLookupExpr *ULE = UnresolvedLookupExpr::Create(
5076 Context, R.getNamingClass(), SS.getWithLocInContext(Context),
5077 TemplateKWLoc, R.getLookupNameInfo(), RequiresADL, TemplateArgs,
5078 R.begin(), R.end(), KnownDependent);
5080 return ULE;
5083 // We actually only call this from template instantiation.
5084 ExprResult
5085 Sema::BuildQualifiedTemplateIdExpr(CXXScopeSpec &SS,
5086 SourceLocation TemplateKWLoc,
5087 const DeclarationNameInfo &NameInfo,
5088 const TemplateArgumentListInfo *TemplateArgs) {
5090 assert(TemplateArgs || TemplateKWLoc.isValid());
5091 DeclContext *DC;
5092 if (!(DC = computeDeclContext(SS, false)) ||
5093 DC->isDependentContext() ||
5094 RequireCompleteDeclContext(SS, DC))
5095 return BuildDependentDeclRefExpr(SS, TemplateKWLoc, NameInfo, TemplateArgs);
5097 bool MemberOfUnknownSpecialization;
5098 LookupResult R(*this, NameInfo, LookupOrdinaryName);
5099 if (LookupTemplateName(R, (Scope *)nullptr, SS, QualType(),
5100 /*Entering*/false, MemberOfUnknownSpecialization,
5101 TemplateKWLoc))
5102 return ExprError();
5104 if (R.isAmbiguous())
5105 return ExprError();
5107 if (R.empty()) {
5108 Diag(NameInfo.getLoc(), diag::err_no_member)
5109 << NameInfo.getName() << DC << SS.getRange();
5110 return ExprError();
5113 auto DiagnoseTypeTemplateDecl = [&](TemplateDecl *Temp,
5114 bool isTypeAliasTemplateDecl) {
5115 Diag(NameInfo.getLoc(), diag::err_template_kw_refers_to_type_template)
5116 << SS.getScopeRep() << NameInfo.getName().getAsString() << SS.getRange()
5117 << isTypeAliasTemplateDecl;
5118 Diag(Temp->getLocation(), diag::note_referenced_type_template) << 0;
5119 return ExprError();
5122 if (ClassTemplateDecl *Temp = R.getAsSingle<ClassTemplateDecl>())
5123 return DiagnoseTypeTemplateDecl(Temp, false);
5125 if (TypeAliasTemplateDecl *Temp = R.getAsSingle<TypeAliasTemplateDecl>())
5126 return DiagnoseTypeTemplateDecl(Temp, true);
5128 return BuildTemplateIdExpr(SS, TemplateKWLoc, R, /*ADL*/ false, TemplateArgs);
5131 /// Form a template name from a name that is syntactically required to name a
5132 /// template, either due to use of the 'template' keyword or because a name in
5133 /// this syntactic context is assumed to name a template (C++ [temp.names]p2-4).
5135 /// This action forms a template name given the name of the template and its
5136 /// optional scope specifier. This is used when the 'template' keyword is used
5137 /// or when the parsing context unambiguously treats a following '<' as
5138 /// introducing a template argument list. Note that this may produce a
5139 /// non-dependent template name if we can perform the lookup now and identify
5140 /// the named template.
5142 /// For example, given "x.MetaFun::template apply", the scope specifier
5143 /// \p SS will be "MetaFun::", \p TemplateKWLoc contains the location
5144 /// of the "template" keyword, and "apply" is the \p Name.
5145 TemplateNameKind Sema::ActOnTemplateName(Scope *S,
5146 CXXScopeSpec &SS,
5147 SourceLocation TemplateKWLoc,
5148 const UnqualifiedId &Name,
5149 ParsedType ObjectType,
5150 bool EnteringContext,
5151 TemplateTy &Result,
5152 bool AllowInjectedClassName) {
5153 if (TemplateKWLoc.isValid() && S && !S->getTemplateParamParent())
5154 Diag(TemplateKWLoc,
5155 getLangOpts().CPlusPlus11 ?
5156 diag::warn_cxx98_compat_template_outside_of_template :
5157 diag::ext_template_outside_of_template)
5158 << FixItHint::CreateRemoval(TemplateKWLoc);
5160 if (SS.isInvalid())
5161 return TNK_Non_template;
5163 // Figure out where isTemplateName is going to look.
5164 DeclContext *LookupCtx = nullptr;
5165 if (SS.isNotEmpty())
5166 LookupCtx = computeDeclContext(SS, EnteringContext);
5167 else if (ObjectType)
5168 LookupCtx = computeDeclContext(GetTypeFromParser(ObjectType));
5170 // C++0x [temp.names]p5:
5171 // If a name prefixed by the keyword template is not the name of
5172 // a template, the program is ill-formed. [Note: the keyword
5173 // template may not be applied to non-template members of class
5174 // templates. -end note ] [ Note: as is the case with the
5175 // typename prefix, the template prefix is allowed in cases
5176 // where it is not strictly necessary; i.e., when the
5177 // nested-name-specifier or the expression on the left of the ->
5178 // or . is not dependent on a template-parameter, or the use
5179 // does not appear in the scope of a template. -end note]
5181 // Note: C++03 was more strict here, because it banned the use of
5182 // the "template" keyword prior to a template-name that was not a
5183 // dependent name. C++ DR468 relaxed this requirement (the
5184 // "template" keyword is now permitted). We follow the C++0x
5185 // rules, even in C++03 mode with a warning, retroactively applying the DR.
5186 bool MemberOfUnknownSpecialization;
5187 TemplateNameKind TNK = isTemplateName(S, SS, TemplateKWLoc.isValid(), Name,
5188 ObjectType, EnteringContext, Result,
5189 MemberOfUnknownSpecialization);
5190 if (TNK != TNK_Non_template) {
5191 // We resolved this to a (non-dependent) template name. Return it.
5192 auto *LookupRD = dyn_cast_or_null<CXXRecordDecl>(LookupCtx);
5193 if (!AllowInjectedClassName && SS.isNotEmpty() && LookupRD &&
5194 Name.getKind() == UnqualifiedIdKind::IK_Identifier &&
5195 Name.Identifier && LookupRD->getIdentifier() == Name.Identifier) {
5196 // C++14 [class.qual]p2:
5197 // In a lookup in which function names are not ignored and the
5198 // nested-name-specifier nominates a class C, if the name specified
5199 // [...] is the injected-class-name of C, [...] the name is instead
5200 // considered to name the constructor
5202 // We don't get here if naming the constructor would be valid, so we
5203 // just reject immediately and recover by treating the
5204 // injected-class-name as naming the template.
5205 Diag(Name.getBeginLoc(),
5206 diag::ext_out_of_line_qualified_id_type_names_constructor)
5207 << Name.Identifier
5208 << 0 /*injected-class-name used as template name*/
5209 << TemplateKWLoc.isValid();
5211 return TNK;
5214 if (!MemberOfUnknownSpecialization) {
5215 // Didn't find a template name, and the lookup wasn't dependent.
5216 // Do the lookup again to determine if this is a "nothing found" case or
5217 // a "not a template" case. FIXME: Refactor isTemplateName so we don't
5218 // need to do this.
5219 DeclarationNameInfo DNI = GetNameFromUnqualifiedId(Name);
5220 LookupResult R(*this, DNI.getName(), Name.getBeginLoc(),
5221 LookupOrdinaryName);
5222 bool MOUS;
5223 // Tell LookupTemplateName that we require a template so that it diagnoses
5224 // cases where it finds a non-template.
5225 RequiredTemplateKind RTK = TemplateKWLoc.isValid()
5226 ? RequiredTemplateKind(TemplateKWLoc)
5227 : TemplateNameIsRequired;
5228 if (!LookupTemplateName(R, S, SS, ObjectType.get(), EnteringContext, MOUS,
5229 RTK, nullptr, /*AllowTypoCorrection=*/false) &&
5230 !R.isAmbiguous()) {
5231 if (LookupCtx)
5232 Diag(Name.getBeginLoc(), diag::err_no_member)
5233 << DNI.getName() << LookupCtx << SS.getRange();
5234 else
5235 Diag(Name.getBeginLoc(), diag::err_undeclared_use)
5236 << DNI.getName() << SS.getRange();
5238 return TNK_Non_template;
5241 NestedNameSpecifier *Qualifier = SS.getScopeRep();
5243 switch (Name.getKind()) {
5244 case UnqualifiedIdKind::IK_Identifier:
5245 Result = TemplateTy::make(
5246 Context.getDependentTemplateName(Qualifier, Name.Identifier));
5247 return TNK_Dependent_template_name;
5249 case UnqualifiedIdKind::IK_OperatorFunctionId:
5250 Result = TemplateTy::make(Context.getDependentTemplateName(
5251 Qualifier, Name.OperatorFunctionId.Operator));
5252 return TNK_Function_template;
5254 case UnqualifiedIdKind::IK_LiteralOperatorId:
5255 // This is a kind of template name, but can never occur in a dependent
5256 // scope (literal operators can only be declared at namespace scope).
5257 break;
5259 default:
5260 break;
5263 // This name cannot possibly name a dependent template. Diagnose this now
5264 // rather than building a dependent template name that can never be valid.
5265 Diag(Name.getBeginLoc(),
5266 diag::err_template_kw_refers_to_dependent_non_template)
5267 << GetNameFromUnqualifiedId(Name).getName() << Name.getSourceRange()
5268 << TemplateKWLoc.isValid() << TemplateKWLoc;
5269 return TNK_Non_template;
5272 bool Sema::CheckTemplateTypeArgument(
5273 TemplateTypeParmDecl *Param, TemplateArgumentLoc &AL,
5274 SmallVectorImpl<TemplateArgument> &SugaredConverted,
5275 SmallVectorImpl<TemplateArgument> &CanonicalConverted) {
5276 const TemplateArgument &Arg = AL.getArgument();
5277 QualType ArgType;
5278 TypeSourceInfo *TSI = nullptr;
5280 // Check template type parameter.
5281 switch(Arg.getKind()) {
5282 case TemplateArgument::Type:
5283 // C++ [temp.arg.type]p1:
5284 // A template-argument for a template-parameter which is a
5285 // type shall be a type-id.
5286 ArgType = Arg.getAsType();
5287 TSI = AL.getTypeSourceInfo();
5288 break;
5289 case TemplateArgument::Template:
5290 case TemplateArgument::TemplateExpansion: {
5291 // We have a template type parameter but the template argument
5292 // is a template without any arguments.
5293 SourceRange SR = AL.getSourceRange();
5294 TemplateName Name = Arg.getAsTemplateOrTemplatePattern();
5295 diagnoseMissingTemplateArguments(Name, SR.getEnd());
5296 return true;
5298 case TemplateArgument::Expression: {
5299 // We have a template type parameter but the template argument is an
5300 // expression; see if maybe it is missing the "typename" keyword.
5301 CXXScopeSpec SS;
5302 DeclarationNameInfo NameInfo;
5304 if (DependentScopeDeclRefExpr *ArgExpr =
5305 dyn_cast<DependentScopeDeclRefExpr>(Arg.getAsExpr())) {
5306 SS.Adopt(ArgExpr->getQualifierLoc());
5307 NameInfo = ArgExpr->getNameInfo();
5308 } else if (CXXDependentScopeMemberExpr *ArgExpr =
5309 dyn_cast<CXXDependentScopeMemberExpr>(Arg.getAsExpr())) {
5310 if (ArgExpr->isImplicitAccess()) {
5311 SS.Adopt(ArgExpr->getQualifierLoc());
5312 NameInfo = ArgExpr->getMemberNameInfo();
5316 if (auto *II = NameInfo.getName().getAsIdentifierInfo()) {
5317 LookupResult Result(*this, NameInfo, LookupOrdinaryName);
5318 LookupParsedName(Result, CurScope, &SS);
5320 if (Result.getAsSingle<TypeDecl>() ||
5321 Result.getResultKind() ==
5322 LookupResult::NotFoundInCurrentInstantiation) {
5323 assert(SS.getScopeRep() && "dependent scope expr must has a scope!");
5324 // Suggest that the user add 'typename' before the NNS.
5325 SourceLocation Loc = AL.getSourceRange().getBegin();
5326 Diag(Loc, getLangOpts().MSVCCompat
5327 ? diag::ext_ms_template_type_arg_missing_typename
5328 : diag::err_template_arg_must_be_type_suggest)
5329 << FixItHint::CreateInsertion(Loc, "typename ");
5330 NoteTemplateParameterLocation(*Param);
5332 // Recover by synthesizing a type using the location information that we
5333 // already have.
5334 ArgType = Context.getDependentNameType(ElaboratedTypeKeyword::Typename,
5335 SS.getScopeRep(), II);
5336 TypeLocBuilder TLB;
5337 DependentNameTypeLoc TL = TLB.push<DependentNameTypeLoc>(ArgType);
5338 TL.setElaboratedKeywordLoc(SourceLocation(/*synthesized*/));
5339 TL.setQualifierLoc(SS.getWithLocInContext(Context));
5340 TL.setNameLoc(NameInfo.getLoc());
5341 TSI = TLB.getTypeSourceInfo(Context, ArgType);
5343 // Overwrite our input TemplateArgumentLoc so that we can recover
5344 // properly.
5345 AL = TemplateArgumentLoc(TemplateArgument(ArgType),
5346 TemplateArgumentLocInfo(TSI));
5348 break;
5351 // fallthrough
5352 [[fallthrough]];
5354 default: {
5355 // We have a template type parameter but the template argument
5356 // is not a type.
5357 SourceRange SR = AL.getSourceRange();
5358 Diag(SR.getBegin(), diag::err_template_arg_must_be_type) << SR;
5359 NoteTemplateParameterLocation(*Param);
5361 return true;
5365 if (CheckTemplateArgument(TSI))
5366 return true;
5368 // Objective-C ARC:
5369 // If an explicitly-specified template argument type is a lifetime type
5370 // with no lifetime qualifier, the __strong lifetime qualifier is inferred.
5371 if (getLangOpts().ObjCAutoRefCount &&
5372 ArgType->isObjCLifetimeType() &&
5373 !ArgType.getObjCLifetime()) {
5374 Qualifiers Qs;
5375 Qs.setObjCLifetime(Qualifiers::OCL_Strong);
5376 ArgType = Context.getQualifiedType(ArgType, Qs);
5379 SugaredConverted.push_back(TemplateArgument(ArgType));
5380 CanonicalConverted.push_back(
5381 TemplateArgument(Context.getCanonicalType(ArgType)));
5382 return false;
5385 /// Substitute template arguments into the default template argument for
5386 /// the given template type parameter.
5388 /// \param SemaRef the semantic analysis object for which we are performing
5389 /// the substitution.
5391 /// \param Template the template that we are synthesizing template arguments
5392 /// for.
5394 /// \param TemplateLoc the location of the template name that started the
5395 /// template-id we are checking.
5397 /// \param RAngleLoc the location of the right angle bracket ('>') that
5398 /// terminates the template-id.
5400 /// \param Param the template template parameter whose default we are
5401 /// substituting into.
5403 /// \param Converted the list of template arguments provided for template
5404 /// parameters that precede \p Param in the template parameter list.
5405 /// \returns the substituted template argument, or NULL if an error occurred.
5406 static TypeSourceInfo *SubstDefaultTemplateArgument(
5407 Sema &SemaRef, TemplateDecl *Template, SourceLocation TemplateLoc,
5408 SourceLocation RAngleLoc, TemplateTypeParmDecl *Param,
5409 ArrayRef<TemplateArgument> SugaredConverted,
5410 ArrayRef<TemplateArgument> CanonicalConverted) {
5411 TypeSourceInfo *ArgType = Param->getDefaultArgumentInfo();
5413 // If the argument type is dependent, instantiate it now based
5414 // on the previously-computed template arguments.
5415 if (ArgType->getType()->isInstantiationDependentType()) {
5416 Sema::InstantiatingTemplate Inst(SemaRef, TemplateLoc, Param, Template,
5417 SugaredConverted,
5418 SourceRange(TemplateLoc, RAngleLoc));
5419 if (Inst.isInvalid())
5420 return nullptr;
5422 // Only substitute for the innermost template argument list.
5423 MultiLevelTemplateArgumentList TemplateArgLists(Template, SugaredConverted,
5424 /*Final=*/true);
5425 for (unsigned i = 0, e = Param->getDepth(); i != e; ++i)
5426 TemplateArgLists.addOuterTemplateArguments(std::nullopt);
5428 bool ForLambdaCallOperator = false;
5429 if (const auto *Rec = dyn_cast<CXXRecordDecl>(Template->getDeclContext()))
5430 ForLambdaCallOperator = Rec->isLambda();
5431 Sema::ContextRAII SavedContext(SemaRef, Template->getDeclContext(),
5432 !ForLambdaCallOperator);
5433 ArgType =
5434 SemaRef.SubstType(ArgType, TemplateArgLists,
5435 Param->getDefaultArgumentLoc(), Param->getDeclName());
5438 return ArgType;
5441 /// Substitute template arguments into the default template argument for
5442 /// the given non-type template parameter.
5444 /// \param SemaRef the semantic analysis object for which we are performing
5445 /// the substitution.
5447 /// \param Template the template that we are synthesizing template arguments
5448 /// for.
5450 /// \param TemplateLoc the location of the template name that started the
5451 /// template-id we are checking.
5453 /// \param RAngleLoc the location of the right angle bracket ('>') that
5454 /// terminates the template-id.
5456 /// \param Param the non-type template parameter whose default we are
5457 /// substituting into.
5459 /// \param Converted the list of template arguments provided for template
5460 /// parameters that precede \p Param in the template parameter list.
5462 /// \returns the substituted template argument, or NULL if an error occurred.
5463 static ExprResult SubstDefaultTemplateArgument(
5464 Sema &SemaRef, TemplateDecl *Template, SourceLocation TemplateLoc,
5465 SourceLocation RAngleLoc, NonTypeTemplateParmDecl *Param,
5466 ArrayRef<TemplateArgument> SugaredConverted,
5467 ArrayRef<TemplateArgument> CanonicalConverted) {
5468 Sema::InstantiatingTemplate Inst(SemaRef, TemplateLoc, Param, Template,
5469 SugaredConverted,
5470 SourceRange(TemplateLoc, RAngleLoc));
5471 if (Inst.isInvalid())
5472 return ExprError();
5474 // Only substitute for the innermost template argument list.
5475 MultiLevelTemplateArgumentList TemplateArgLists(Template, SugaredConverted,
5476 /*Final=*/true);
5477 for (unsigned i = 0, e = Param->getDepth(); i != e; ++i)
5478 TemplateArgLists.addOuterTemplateArguments(std::nullopt);
5480 Sema::ContextRAII SavedContext(SemaRef, Template->getDeclContext());
5481 EnterExpressionEvaluationContext ConstantEvaluated(
5482 SemaRef, Sema::ExpressionEvaluationContext::ConstantEvaluated);
5483 return SemaRef.SubstExpr(Param->getDefaultArgument(), TemplateArgLists);
5486 /// Substitute template arguments into the default template argument for
5487 /// the given template template parameter.
5489 /// \param SemaRef the semantic analysis object for which we are performing
5490 /// the substitution.
5492 /// \param Template the template that we are synthesizing template arguments
5493 /// for.
5495 /// \param TemplateLoc the location of the template name that started the
5496 /// template-id we are checking.
5498 /// \param RAngleLoc the location of the right angle bracket ('>') that
5499 /// terminates the template-id.
5501 /// \param Param the template template parameter whose default we are
5502 /// substituting into.
5504 /// \param Converted the list of template arguments provided for template
5505 /// parameters that precede \p Param in the template parameter list.
5507 /// \param QualifierLoc Will be set to the nested-name-specifier (with
5508 /// source-location information) that precedes the template name.
5510 /// \returns the substituted template argument, or NULL if an error occurred.
5511 static TemplateName SubstDefaultTemplateArgument(
5512 Sema &SemaRef, TemplateDecl *Template, SourceLocation TemplateLoc,
5513 SourceLocation RAngleLoc, TemplateTemplateParmDecl *Param,
5514 ArrayRef<TemplateArgument> SugaredConverted,
5515 ArrayRef<TemplateArgument> CanonicalConverted,
5516 NestedNameSpecifierLoc &QualifierLoc) {
5517 Sema::InstantiatingTemplate Inst(
5518 SemaRef, TemplateLoc, TemplateParameter(Param), Template,
5519 SugaredConverted, SourceRange(TemplateLoc, RAngleLoc));
5520 if (Inst.isInvalid())
5521 return TemplateName();
5523 // Only substitute for the innermost template argument list.
5524 MultiLevelTemplateArgumentList TemplateArgLists(Template, SugaredConverted,
5525 /*Final=*/true);
5526 for (unsigned i = 0, e = Param->getDepth(); i != e; ++i)
5527 TemplateArgLists.addOuterTemplateArguments(std::nullopt);
5529 Sema::ContextRAII SavedContext(SemaRef, Template->getDeclContext());
5530 // Substitute into the nested-name-specifier first,
5531 QualifierLoc = Param->getDefaultArgument().getTemplateQualifierLoc();
5532 if (QualifierLoc) {
5533 QualifierLoc =
5534 SemaRef.SubstNestedNameSpecifierLoc(QualifierLoc, TemplateArgLists);
5535 if (!QualifierLoc)
5536 return TemplateName();
5539 return SemaRef.SubstTemplateName(
5540 QualifierLoc,
5541 Param->getDefaultArgument().getArgument().getAsTemplate(),
5542 Param->getDefaultArgument().getTemplateNameLoc(),
5543 TemplateArgLists);
5546 /// If the given template parameter has a default template
5547 /// argument, substitute into that default template argument and
5548 /// return the corresponding template argument.
5549 TemplateArgumentLoc Sema::SubstDefaultTemplateArgumentIfAvailable(
5550 TemplateDecl *Template, SourceLocation TemplateLoc,
5551 SourceLocation RAngleLoc, Decl *Param,
5552 ArrayRef<TemplateArgument> SugaredConverted,
5553 ArrayRef<TemplateArgument> CanonicalConverted, bool &HasDefaultArg) {
5554 HasDefaultArg = false;
5556 if (TemplateTypeParmDecl *TypeParm = dyn_cast<TemplateTypeParmDecl>(Param)) {
5557 if (!hasReachableDefaultArgument(TypeParm))
5558 return TemplateArgumentLoc();
5560 HasDefaultArg = true;
5561 TypeSourceInfo *DI = SubstDefaultTemplateArgument(
5562 *this, Template, TemplateLoc, RAngleLoc, TypeParm, SugaredConverted,
5563 CanonicalConverted);
5564 if (DI)
5565 return TemplateArgumentLoc(TemplateArgument(DI->getType()), DI);
5567 return TemplateArgumentLoc();
5570 if (NonTypeTemplateParmDecl *NonTypeParm
5571 = dyn_cast<NonTypeTemplateParmDecl>(Param)) {
5572 if (!hasReachableDefaultArgument(NonTypeParm))
5573 return TemplateArgumentLoc();
5575 HasDefaultArg = true;
5576 ExprResult Arg = SubstDefaultTemplateArgument(
5577 *this, Template, TemplateLoc, RAngleLoc, NonTypeParm, SugaredConverted,
5578 CanonicalConverted);
5579 if (Arg.isInvalid())
5580 return TemplateArgumentLoc();
5582 Expr *ArgE = Arg.getAs<Expr>();
5583 return TemplateArgumentLoc(TemplateArgument(ArgE), ArgE);
5586 TemplateTemplateParmDecl *TempTempParm
5587 = cast<TemplateTemplateParmDecl>(Param);
5588 if (!hasReachableDefaultArgument(TempTempParm))
5589 return TemplateArgumentLoc();
5591 HasDefaultArg = true;
5592 NestedNameSpecifierLoc QualifierLoc;
5593 TemplateName TName = SubstDefaultTemplateArgument(
5594 *this, Template, TemplateLoc, RAngleLoc, TempTempParm, SugaredConverted,
5595 CanonicalConverted, QualifierLoc);
5596 if (TName.isNull())
5597 return TemplateArgumentLoc();
5599 return TemplateArgumentLoc(
5600 Context, TemplateArgument(TName),
5601 TempTempParm->getDefaultArgument().getTemplateQualifierLoc(),
5602 TempTempParm->getDefaultArgument().getTemplateNameLoc());
5605 /// Convert a template-argument that we parsed as a type into a template, if
5606 /// possible. C++ permits injected-class-names to perform dual service as
5607 /// template template arguments and as template type arguments.
5608 static TemplateArgumentLoc
5609 convertTypeTemplateArgumentToTemplate(ASTContext &Context, TypeLoc TLoc) {
5610 // Extract and step over any surrounding nested-name-specifier.
5611 NestedNameSpecifierLoc QualLoc;
5612 if (auto ETLoc = TLoc.getAs<ElaboratedTypeLoc>()) {
5613 if (ETLoc.getTypePtr()->getKeyword() != ElaboratedTypeKeyword::None)
5614 return TemplateArgumentLoc();
5616 QualLoc = ETLoc.getQualifierLoc();
5617 TLoc = ETLoc.getNamedTypeLoc();
5619 // If this type was written as an injected-class-name, it can be used as a
5620 // template template argument.
5621 if (auto InjLoc = TLoc.getAs<InjectedClassNameTypeLoc>())
5622 return TemplateArgumentLoc(Context, InjLoc.getTypePtr()->getTemplateName(),
5623 QualLoc, InjLoc.getNameLoc());
5625 // If this type was written as an injected-class-name, it may have been
5626 // converted to a RecordType during instantiation. If the RecordType is
5627 // *not* wrapped in a TemplateSpecializationType and denotes a class
5628 // template specialization, it must have come from an injected-class-name.
5629 if (auto RecLoc = TLoc.getAs<RecordTypeLoc>())
5630 if (auto *CTSD =
5631 dyn_cast<ClassTemplateSpecializationDecl>(RecLoc.getDecl()))
5632 return TemplateArgumentLoc(Context,
5633 TemplateName(CTSD->getSpecializedTemplate()),
5634 QualLoc, RecLoc.getNameLoc());
5636 return TemplateArgumentLoc();
5639 /// Check that the given template argument corresponds to the given
5640 /// template parameter.
5642 /// \param Param The template parameter against which the argument will be
5643 /// checked.
5645 /// \param Arg The template argument, which may be updated due to conversions.
5647 /// \param Template The template in which the template argument resides.
5649 /// \param TemplateLoc The location of the template name for the template
5650 /// whose argument list we're matching.
5652 /// \param RAngleLoc The location of the right angle bracket ('>') that closes
5653 /// the template argument list.
5655 /// \param ArgumentPackIndex The index into the argument pack where this
5656 /// argument will be placed. Only valid if the parameter is a parameter pack.
5658 /// \param Converted The checked, converted argument will be added to the
5659 /// end of this small vector.
5661 /// \param CTAK Describes how we arrived at this particular template argument:
5662 /// explicitly written, deduced, etc.
5664 /// \returns true on error, false otherwise.
5665 bool Sema::CheckTemplateArgument(
5666 NamedDecl *Param, TemplateArgumentLoc &Arg, NamedDecl *Template,
5667 SourceLocation TemplateLoc, SourceLocation RAngleLoc,
5668 unsigned ArgumentPackIndex,
5669 SmallVectorImpl<TemplateArgument> &SugaredConverted,
5670 SmallVectorImpl<TemplateArgument> &CanonicalConverted,
5671 CheckTemplateArgumentKind CTAK) {
5672 // Check template type parameters.
5673 if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(Param))
5674 return CheckTemplateTypeArgument(TTP, Arg, SugaredConverted,
5675 CanonicalConverted);
5677 // Check non-type template parameters.
5678 if (NonTypeTemplateParmDecl *NTTP =dyn_cast<NonTypeTemplateParmDecl>(Param)) {
5679 // Do substitution on the type of the non-type template parameter
5680 // with the template arguments we've seen thus far. But if the
5681 // template has a dependent context then we cannot substitute yet.
5682 QualType NTTPType = NTTP->getType();
5683 if (NTTP->isParameterPack() && NTTP->isExpandedParameterPack())
5684 NTTPType = NTTP->getExpansionType(ArgumentPackIndex);
5686 if (NTTPType->isInstantiationDependentType() &&
5687 !isa<TemplateTemplateParmDecl>(Template) &&
5688 !Template->getDeclContext()->isDependentContext()) {
5689 // Do substitution on the type of the non-type template parameter.
5690 InstantiatingTemplate Inst(*this, TemplateLoc, Template, NTTP,
5691 SugaredConverted,
5692 SourceRange(TemplateLoc, RAngleLoc));
5693 if (Inst.isInvalid())
5694 return true;
5696 MultiLevelTemplateArgumentList MLTAL(Template, SugaredConverted,
5697 /*Final=*/true);
5698 // If the parameter is a pack expansion, expand this slice of the pack.
5699 if (auto *PET = NTTPType->getAs<PackExpansionType>()) {
5700 Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(*this,
5701 ArgumentPackIndex);
5702 NTTPType = SubstType(PET->getPattern(), MLTAL, NTTP->getLocation(),
5703 NTTP->getDeclName());
5704 } else {
5705 NTTPType = SubstType(NTTPType, MLTAL, NTTP->getLocation(),
5706 NTTP->getDeclName());
5709 // If that worked, check the non-type template parameter type
5710 // for validity.
5711 if (!NTTPType.isNull())
5712 NTTPType = CheckNonTypeTemplateParameterType(NTTPType,
5713 NTTP->getLocation());
5714 if (NTTPType.isNull())
5715 return true;
5718 switch (Arg.getArgument().getKind()) {
5719 case TemplateArgument::Null:
5720 llvm_unreachable("Should never see a NULL template argument here");
5722 case TemplateArgument::Expression: {
5723 Expr *E = Arg.getArgument().getAsExpr();
5724 TemplateArgument SugaredResult, CanonicalResult;
5725 unsigned CurSFINAEErrors = NumSFINAEErrors;
5726 ExprResult Res = CheckTemplateArgument(NTTP, NTTPType, E, SugaredResult,
5727 CanonicalResult, CTAK);
5728 if (Res.isInvalid())
5729 return true;
5730 // If the current template argument causes an error, give up now.
5731 if (CurSFINAEErrors < NumSFINAEErrors)
5732 return true;
5734 // If the resulting expression is new, then use it in place of the
5735 // old expression in the template argument.
5736 if (Res.get() != E) {
5737 TemplateArgument TA(Res.get());
5738 Arg = TemplateArgumentLoc(TA, Res.get());
5741 SugaredConverted.push_back(SugaredResult);
5742 CanonicalConverted.push_back(CanonicalResult);
5743 break;
5746 case TemplateArgument::Declaration:
5747 case TemplateArgument::Integral:
5748 case TemplateArgument::NullPtr:
5749 // We've already checked this template argument, so just copy
5750 // it to the list of converted arguments.
5751 SugaredConverted.push_back(Arg.getArgument());
5752 CanonicalConverted.push_back(
5753 Context.getCanonicalTemplateArgument(Arg.getArgument()));
5754 break;
5756 case TemplateArgument::Template:
5757 case TemplateArgument::TemplateExpansion:
5758 // We were given a template template argument. It may not be ill-formed;
5759 // see below.
5760 if (DependentTemplateName *DTN
5761 = Arg.getArgument().getAsTemplateOrTemplatePattern()
5762 .getAsDependentTemplateName()) {
5763 // We have a template argument such as \c T::template X, which we
5764 // parsed as a template template argument. However, since we now
5765 // know that we need a non-type template argument, convert this
5766 // template name into an expression.
5768 DeclarationNameInfo NameInfo(DTN->getIdentifier(),
5769 Arg.getTemplateNameLoc());
5771 CXXScopeSpec SS;
5772 SS.Adopt(Arg.getTemplateQualifierLoc());
5773 // FIXME: the template-template arg was a DependentTemplateName,
5774 // so it was provided with a template keyword. However, its source
5775 // location is not stored in the template argument structure.
5776 SourceLocation TemplateKWLoc;
5777 ExprResult E = DependentScopeDeclRefExpr::Create(
5778 Context, SS.getWithLocInContext(Context), TemplateKWLoc, NameInfo,
5779 nullptr);
5781 // If we parsed the template argument as a pack expansion, create a
5782 // pack expansion expression.
5783 if (Arg.getArgument().getKind() == TemplateArgument::TemplateExpansion){
5784 E = ActOnPackExpansion(E.get(), Arg.getTemplateEllipsisLoc());
5785 if (E.isInvalid())
5786 return true;
5789 TemplateArgument SugaredResult, CanonicalResult;
5790 E = CheckTemplateArgument(NTTP, NTTPType, E.get(), SugaredResult,
5791 CanonicalResult, CTAK_Specified);
5792 if (E.isInvalid())
5793 return true;
5795 SugaredConverted.push_back(SugaredResult);
5796 CanonicalConverted.push_back(CanonicalResult);
5797 break;
5800 // We have a template argument that actually does refer to a class
5801 // template, alias template, or template template parameter, and
5802 // therefore cannot be a non-type template argument.
5803 Diag(Arg.getLocation(), diag::err_template_arg_must_be_expr)
5804 << Arg.getSourceRange();
5805 NoteTemplateParameterLocation(*Param);
5807 return true;
5809 case TemplateArgument::Type: {
5810 // We have a non-type template parameter but the template
5811 // argument is a type.
5813 // C++ [temp.arg]p2:
5814 // In a template-argument, an ambiguity between a type-id and
5815 // an expression is resolved to a type-id, regardless of the
5816 // form of the corresponding template-parameter.
5818 // We warn specifically about this case, since it can be rather
5819 // confusing for users.
5820 QualType T = Arg.getArgument().getAsType();
5821 SourceRange SR = Arg.getSourceRange();
5822 if (T->isFunctionType())
5823 Diag(SR.getBegin(), diag::err_template_arg_nontype_ambig) << SR << T;
5824 else
5825 Diag(SR.getBegin(), diag::err_template_arg_must_be_expr) << SR;
5826 NoteTemplateParameterLocation(*Param);
5827 return true;
5830 case TemplateArgument::Pack:
5831 llvm_unreachable("Caller must expand template argument packs");
5834 return false;
5838 // Check template template parameters.
5839 TemplateTemplateParmDecl *TempParm = cast<TemplateTemplateParmDecl>(Param);
5841 TemplateParameterList *Params = TempParm->getTemplateParameters();
5842 if (TempParm->isExpandedParameterPack())
5843 Params = TempParm->getExpansionTemplateParameters(ArgumentPackIndex);
5845 // Substitute into the template parameter list of the template
5846 // template parameter, since previously-supplied template arguments
5847 // may appear within the template template parameter.
5849 // FIXME: Skip this if the parameters aren't instantiation-dependent.
5851 // Set up a template instantiation context.
5852 LocalInstantiationScope Scope(*this);
5853 InstantiatingTemplate Inst(*this, TemplateLoc, Template, TempParm,
5854 SugaredConverted,
5855 SourceRange(TemplateLoc, RAngleLoc));
5856 if (Inst.isInvalid())
5857 return true;
5859 Params =
5860 SubstTemplateParams(Params, CurContext,
5861 MultiLevelTemplateArgumentList(
5862 Template, SugaredConverted, /*Final=*/true),
5863 /*EvaluateConstraints=*/false);
5864 if (!Params)
5865 return true;
5868 // C++1z [temp.local]p1: (DR1004)
5869 // When [the injected-class-name] is used [...] as a template-argument for
5870 // a template template-parameter [...] it refers to the class template
5871 // itself.
5872 if (Arg.getArgument().getKind() == TemplateArgument::Type) {
5873 TemplateArgumentLoc ConvertedArg = convertTypeTemplateArgumentToTemplate(
5874 Context, Arg.getTypeSourceInfo()->getTypeLoc());
5875 if (!ConvertedArg.getArgument().isNull())
5876 Arg = ConvertedArg;
5879 switch (Arg.getArgument().getKind()) {
5880 case TemplateArgument::Null:
5881 llvm_unreachable("Should never see a NULL template argument here");
5883 case TemplateArgument::Template:
5884 case TemplateArgument::TemplateExpansion:
5885 if (CheckTemplateTemplateArgument(TempParm, Params, Arg))
5886 return true;
5888 SugaredConverted.push_back(Arg.getArgument());
5889 CanonicalConverted.push_back(
5890 Context.getCanonicalTemplateArgument(Arg.getArgument()));
5891 break;
5893 case TemplateArgument::Expression:
5894 case TemplateArgument::Type:
5895 // We have a template template parameter but the template
5896 // argument does not refer to a template.
5897 Diag(Arg.getLocation(), diag::err_template_arg_must_be_template)
5898 << getLangOpts().CPlusPlus11;
5899 return true;
5901 case TemplateArgument::Declaration:
5902 llvm_unreachable("Declaration argument with template template parameter");
5903 case TemplateArgument::Integral:
5904 llvm_unreachable("Integral argument with template template parameter");
5905 case TemplateArgument::NullPtr:
5906 llvm_unreachable("Null pointer argument with template template parameter");
5908 case TemplateArgument::Pack:
5909 llvm_unreachable("Caller must expand template argument packs");
5912 return false;
5915 /// Diagnose a missing template argument.
5916 template<typename TemplateParmDecl>
5917 static bool diagnoseMissingArgument(Sema &S, SourceLocation Loc,
5918 TemplateDecl *TD,
5919 const TemplateParmDecl *D,
5920 TemplateArgumentListInfo &Args) {
5921 // Dig out the most recent declaration of the template parameter; there may be
5922 // declarations of the template that are more recent than TD.
5923 D = cast<TemplateParmDecl>(cast<TemplateDecl>(TD->getMostRecentDecl())
5924 ->getTemplateParameters()
5925 ->getParam(D->getIndex()));
5927 // If there's a default argument that's not reachable, diagnose that we're
5928 // missing a module import.
5929 llvm::SmallVector<Module*, 8> Modules;
5930 if (D->hasDefaultArgument() && !S.hasReachableDefaultArgument(D, &Modules)) {
5931 S.diagnoseMissingImport(Loc, cast<NamedDecl>(TD),
5932 D->getDefaultArgumentLoc(), Modules,
5933 Sema::MissingImportKind::DefaultArgument,
5934 /*Recover*/true);
5935 return true;
5938 // FIXME: If there's a more recent default argument that *is* visible,
5939 // diagnose that it was declared too late.
5941 TemplateParameterList *Params = TD->getTemplateParameters();
5943 S.Diag(Loc, diag::err_template_arg_list_different_arity)
5944 << /*not enough args*/0
5945 << (int)S.getTemplateNameKindForDiagnostics(TemplateName(TD))
5946 << TD;
5947 S.NoteTemplateLocation(*TD, Params->getSourceRange());
5948 return true;
5951 /// Check that the given template argument list is well-formed
5952 /// for specializing the given template.
5953 bool Sema::CheckTemplateArgumentList(
5954 TemplateDecl *Template, SourceLocation TemplateLoc,
5955 TemplateArgumentListInfo &TemplateArgs, bool PartialTemplateArgs,
5956 SmallVectorImpl<TemplateArgument> &SugaredConverted,
5957 SmallVectorImpl<TemplateArgument> &CanonicalConverted,
5958 bool UpdateArgsWithConversions, bool *ConstraintsNotSatisfied) {
5960 if (ConstraintsNotSatisfied)
5961 *ConstraintsNotSatisfied = false;
5963 // Make a copy of the template arguments for processing. Only make the
5964 // changes at the end when successful in matching the arguments to the
5965 // template.
5966 TemplateArgumentListInfo NewArgs = TemplateArgs;
5968 TemplateParameterList *Params = GetTemplateParameterList(Template);
5970 SourceLocation RAngleLoc = NewArgs.getRAngleLoc();
5972 // C++ [temp.arg]p1:
5973 // [...] The type and form of each template-argument specified in
5974 // a template-id shall match the type and form specified for the
5975 // corresponding parameter declared by the template in its
5976 // template-parameter-list.
5977 bool isTemplateTemplateParameter = isa<TemplateTemplateParmDecl>(Template);
5978 SmallVector<TemplateArgument, 2> SugaredArgumentPack;
5979 SmallVector<TemplateArgument, 2> CanonicalArgumentPack;
5980 unsigned ArgIdx = 0, NumArgs = NewArgs.size();
5981 LocalInstantiationScope InstScope(*this, true);
5982 for (TemplateParameterList::iterator Param = Params->begin(),
5983 ParamEnd = Params->end();
5984 Param != ParamEnd; /* increment in loop */) {
5985 // If we have an expanded parameter pack, make sure we don't have too
5986 // many arguments.
5987 if (std::optional<unsigned> Expansions = getExpandedPackSize(*Param)) {
5988 if (*Expansions == SugaredArgumentPack.size()) {
5989 // We're done with this parameter pack. Pack up its arguments and add
5990 // them to the list.
5991 SugaredConverted.push_back(
5992 TemplateArgument::CreatePackCopy(Context, SugaredArgumentPack));
5993 SugaredArgumentPack.clear();
5995 CanonicalConverted.push_back(
5996 TemplateArgument::CreatePackCopy(Context, CanonicalArgumentPack));
5997 CanonicalArgumentPack.clear();
5999 // This argument is assigned to the next parameter.
6000 ++Param;
6001 continue;
6002 } else if (ArgIdx == NumArgs && !PartialTemplateArgs) {
6003 // Not enough arguments for this parameter pack.
6004 Diag(TemplateLoc, diag::err_template_arg_list_different_arity)
6005 << /*not enough args*/0
6006 << (int)getTemplateNameKindForDiagnostics(TemplateName(Template))
6007 << Template;
6008 NoteTemplateLocation(*Template, Params->getSourceRange());
6009 return true;
6013 if (ArgIdx < NumArgs) {
6014 // Check the template argument we were given.
6015 if (CheckTemplateArgument(*Param, NewArgs[ArgIdx], Template, TemplateLoc,
6016 RAngleLoc, SugaredArgumentPack.size(),
6017 SugaredConverted, CanonicalConverted,
6018 CTAK_Specified))
6019 return true;
6021 CanonicalConverted.back().setIsDefaulted(
6022 clang::isSubstitutedDefaultArgument(
6023 Context, NewArgs[ArgIdx].getArgument(), *Param,
6024 CanonicalConverted, Params->getDepth()));
6026 bool PackExpansionIntoNonPack =
6027 NewArgs[ArgIdx].getArgument().isPackExpansion() &&
6028 (!(*Param)->isTemplateParameterPack() || getExpandedPackSize(*Param));
6029 if (PackExpansionIntoNonPack && (isa<TypeAliasTemplateDecl>(Template) ||
6030 isa<ConceptDecl>(Template))) {
6031 // Core issue 1430: we have a pack expansion as an argument to an
6032 // alias template, and it's not part of a parameter pack. This
6033 // can't be canonicalized, so reject it now.
6034 // As for concepts - we cannot normalize constraints where this
6035 // situation exists.
6036 Diag(NewArgs[ArgIdx].getLocation(),
6037 diag::err_template_expansion_into_fixed_list)
6038 << (isa<ConceptDecl>(Template) ? 1 : 0)
6039 << NewArgs[ArgIdx].getSourceRange();
6040 NoteTemplateParameterLocation(**Param);
6041 return true;
6044 // We're now done with this argument.
6045 ++ArgIdx;
6047 if ((*Param)->isTemplateParameterPack()) {
6048 // The template parameter was a template parameter pack, so take the
6049 // deduced argument and place it on the argument pack. Note that we
6050 // stay on the same template parameter so that we can deduce more
6051 // arguments.
6052 SugaredArgumentPack.push_back(SugaredConverted.pop_back_val());
6053 CanonicalArgumentPack.push_back(CanonicalConverted.pop_back_val());
6054 } else {
6055 // Move to the next template parameter.
6056 ++Param;
6059 // If we just saw a pack expansion into a non-pack, then directly convert
6060 // the remaining arguments, because we don't know what parameters they'll
6061 // match up with.
6062 if (PackExpansionIntoNonPack) {
6063 if (!SugaredArgumentPack.empty()) {
6064 // If we were part way through filling in an expanded parameter pack,
6065 // fall back to just producing individual arguments.
6066 SugaredConverted.insert(SugaredConverted.end(),
6067 SugaredArgumentPack.begin(),
6068 SugaredArgumentPack.end());
6069 SugaredArgumentPack.clear();
6071 CanonicalConverted.insert(CanonicalConverted.end(),
6072 CanonicalArgumentPack.begin(),
6073 CanonicalArgumentPack.end());
6074 CanonicalArgumentPack.clear();
6077 while (ArgIdx < NumArgs) {
6078 const TemplateArgument &Arg = NewArgs[ArgIdx].getArgument();
6079 SugaredConverted.push_back(Arg);
6080 CanonicalConverted.push_back(
6081 Context.getCanonicalTemplateArgument(Arg));
6082 ++ArgIdx;
6085 return false;
6088 continue;
6091 // If we're checking a partial template argument list, we're done.
6092 if (PartialTemplateArgs) {
6093 if ((*Param)->isTemplateParameterPack() && !SugaredArgumentPack.empty()) {
6094 SugaredConverted.push_back(
6095 TemplateArgument::CreatePackCopy(Context, SugaredArgumentPack));
6096 CanonicalConverted.push_back(
6097 TemplateArgument::CreatePackCopy(Context, CanonicalArgumentPack));
6099 return false;
6102 // If we have a template parameter pack with no more corresponding
6103 // arguments, just break out now and we'll fill in the argument pack below.
6104 if ((*Param)->isTemplateParameterPack()) {
6105 assert(!getExpandedPackSize(*Param) &&
6106 "Should have dealt with this already");
6108 // A non-expanded parameter pack before the end of the parameter list
6109 // only occurs for an ill-formed template parameter list, unless we've
6110 // got a partial argument list for a function template, so just bail out.
6111 if (Param + 1 != ParamEnd) {
6112 assert(
6113 (Template->getMostRecentDecl()->getKind() != Decl::Kind::Concept) &&
6114 "Concept templates must have parameter packs at the end.");
6115 return true;
6118 SugaredConverted.push_back(
6119 TemplateArgument::CreatePackCopy(Context, SugaredArgumentPack));
6120 SugaredArgumentPack.clear();
6122 CanonicalConverted.push_back(
6123 TemplateArgument::CreatePackCopy(Context, CanonicalArgumentPack));
6124 CanonicalArgumentPack.clear();
6126 ++Param;
6127 continue;
6130 // Check whether we have a default argument.
6131 TemplateArgumentLoc Arg;
6133 // Retrieve the default template argument from the template
6134 // parameter. For each kind of template parameter, we substitute the
6135 // template arguments provided thus far and any "outer" template arguments
6136 // (when the template parameter was part of a nested template) into
6137 // the default argument.
6138 if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(*Param)) {
6139 if (!hasReachableDefaultArgument(TTP))
6140 return diagnoseMissingArgument(*this, TemplateLoc, Template, TTP,
6141 NewArgs);
6143 TypeSourceInfo *ArgType = SubstDefaultTemplateArgument(
6144 *this, Template, TemplateLoc, RAngleLoc, TTP, SugaredConverted,
6145 CanonicalConverted);
6146 if (!ArgType)
6147 return true;
6149 Arg = TemplateArgumentLoc(TemplateArgument(ArgType->getType()),
6150 ArgType);
6151 } else if (NonTypeTemplateParmDecl *NTTP
6152 = dyn_cast<NonTypeTemplateParmDecl>(*Param)) {
6153 if (!hasReachableDefaultArgument(NTTP))
6154 return diagnoseMissingArgument(*this, TemplateLoc, Template, NTTP,
6155 NewArgs);
6157 ExprResult E = SubstDefaultTemplateArgument(
6158 *this, Template, TemplateLoc, RAngleLoc, NTTP, SugaredConverted,
6159 CanonicalConverted);
6160 if (E.isInvalid())
6161 return true;
6163 Expr *Ex = E.getAs<Expr>();
6164 Arg = TemplateArgumentLoc(TemplateArgument(Ex), Ex);
6165 } else {
6166 TemplateTemplateParmDecl *TempParm
6167 = cast<TemplateTemplateParmDecl>(*Param);
6169 if (!hasReachableDefaultArgument(TempParm))
6170 return diagnoseMissingArgument(*this, TemplateLoc, Template, TempParm,
6171 NewArgs);
6173 NestedNameSpecifierLoc QualifierLoc;
6174 TemplateName Name = SubstDefaultTemplateArgument(
6175 *this, Template, TemplateLoc, RAngleLoc, TempParm, SugaredConverted,
6176 CanonicalConverted, QualifierLoc);
6177 if (Name.isNull())
6178 return true;
6180 Arg = TemplateArgumentLoc(
6181 Context, TemplateArgument(Name), QualifierLoc,
6182 TempParm->getDefaultArgument().getTemplateNameLoc());
6185 // Introduce an instantiation record that describes where we are using
6186 // the default template argument. We're not actually instantiating a
6187 // template here, we just create this object to put a note into the
6188 // context stack.
6189 InstantiatingTemplate Inst(*this, RAngleLoc, Template, *Param,
6190 SugaredConverted,
6191 SourceRange(TemplateLoc, RAngleLoc));
6192 if (Inst.isInvalid())
6193 return true;
6195 // Check the default template argument.
6196 if (CheckTemplateArgument(*Param, Arg, Template, TemplateLoc, RAngleLoc, 0,
6197 SugaredConverted, CanonicalConverted,
6198 CTAK_Specified))
6199 return true;
6201 CanonicalConverted.back().setIsDefaulted(true);
6203 // Core issue 150 (assumed resolution): if this is a template template
6204 // parameter, keep track of the default template arguments from the
6205 // template definition.
6206 if (isTemplateTemplateParameter)
6207 NewArgs.addArgument(Arg);
6209 // Move to the next template parameter and argument.
6210 ++Param;
6211 ++ArgIdx;
6214 // If we're performing a partial argument substitution, allow any trailing
6215 // pack expansions; they might be empty. This can happen even if
6216 // PartialTemplateArgs is false (the list of arguments is complete but
6217 // still dependent).
6218 if (ArgIdx < NumArgs && CurrentInstantiationScope &&
6219 CurrentInstantiationScope->getPartiallySubstitutedPack()) {
6220 while (ArgIdx < NumArgs &&
6221 NewArgs[ArgIdx].getArgument().isPackExpansion()) {
6222 const TemplateArgument &Arg = NewArgs[ArgIdx++].getArgument();
6223 SugaredConverted.push_back(Arg);
6224 CanonicalConverted.push_back(Context.getCanonicalTemplateArgument(Arg));
6228 // If we have any leftover arguments, then there were too many arguments.
6229 // Complain and fail.
6230 if (ArgIdx < NumArgs) {
6231 Diag(TemplateLoc, diag::err_template_arg_list_different_arity)
6232 << /*too many args*/1
6233 << (int)getTemplateNameKindForDiagnostics(TemplateName(Template))
6234 << Template
6235 << SourceRange(NewArgs[ArgIdx].getLocation(), NewArgs.getRAngleLoc());
6236 NoteTemplateLocation(*Template, Params->getSourceRange());
6237 return true;
6240 // No problems found with the new argument list, propagate changes back
6241 // to caller.
6242 if (UpdateArgsWithConversions)
6243 TemplateArgs = std::move(NewArgs);
6245 if (!PartialTemplateArgs) {
6246 TemplateArgumentList StackTemplateArgs(TemplateArgumentList::OnStack,
6247 CanonicalConverted);
6248 // Setup the context/ThisScope for the case where we are needing to
6249 // re-instantiate constraints outside of normal instantiation.
6250 DeclContext *NewContext = Template->getDeclContext();
6252 // If this template is in a template, make sure we extract the templated
6253 // decl.
6254 if (auto *TD = dyn_cast<TemplateDecl>(NewContext))
6255 NewContext = Decl::castToDeclContext(TD->getTemplatedDecl());
6256 auto *RD = dyn_cast<CXXRecordDecl>(NewContext);
6258 Qualifiers ThisQuals;
6259 if (const auto *Method =
6260 dyn_cast_or_null<CXXMethodDecl>(Template->getTemplatedDecl()))
6261 ThisQuals = Method->getMethodQualifiers();
6263 ContextRAII Context(*this, NewContext);
6264 CXXThisScopeRAII(*this, RD, ThisQuals, RD != nullptr);
6266 MultiLevelTemplateArgumentList MLTAL = getTemplateInstantiationArgs(
6267 Template, NewContext, /*Final=*/false, &StackTemplateArgs,
6268 /*RelativeToPrimary=*/true,
6269 /*Pattern=*/nullptr,
6270 /*ForConceptInstantiation=*/true);
6271 if (EnsureTemplateArgumentListConstraints(
6272 Template, MLTAL,
6273 SourceRange(TemplateLoc, TemplateArgs.getRAngleLoc()))) {
6274 if (ConstraintsNotSatisfied)
6275 *ConstraintsNotSatisfied = true;
6276 return true;
6280 return false;
6283 namespace {
6284 class UnnamedLocalNoLinkageFinder
6285 : public TypeVisitor<UnnamedLocalNoLinkageFinder, bool>
6287 Sema &S;
6288 SourceRange SR;
6290 typedef TypeVisitor<UnnamedLocalNoLinkageFinder, bool> inherited;
6292 public:
6293 UnnamedLocalNoLinkageFinder(Sema &S, SourceRange SR) : S(S), SR(SR) { }
6295 bool Visit(QualType T) {
6296 return T.isNull() ? false : inherited::Visit(T.getTypePtr());
6299 #define TYPE(Class, Parent) \
6300 bool Visit##Class##Type(const Class##Type *);
6301 #define ABSTRACT_TYPE(Class, Parent) \
6302 bool Visit##Class##Type(const Class##Type *) { return false; }
6303 #define NON_CANONICAL_TYPE(Class, Parent) \
6304 bool Visit##Class##Type(const Class##Type *) { return false; }
6305 #include "clang/AST/TypeNodes.inc"
6307 bool VisitTagDecl(const TagDecl *Tag);
6308 bool VisitNestedNameSpecifier(NestedNameSpecifier *NNS);
6310 } // end anonymous namespace
6312 bool UnnamedLocalNoLinkageFinder::VisitBuiltinType(const BuiltinType*) {
6313 return false;
6316 bool UnnamedLocalNoLinkageFinder::VisitComplexType(const ComplexType* T) {
6317 return Visit(T->getElementType());
6320 bool UnnamedLocalNoLinkageFinder::VisitPointerType(const PointerType* T) {
6321 return Visit(T->getPointeeType());
6324 bool UnnamedLocalNoLinkageFinder::VisitBlockPointerType(
6325 const BlockPointerType* T) {
6326 return Visit(T->getPointeeType());
6329 bool UnnamedLocalNoLinkageFinder::VisitLValueReferenceType(
6330 const LValueReferenceType* T) {
6331 return Visit(T->getPointeeType());
6334 bool UnnamedLocalNoLinkageFinder::VisitRValueReferenceType(
6335 const RValueReferenceType* T) {
6336 return Visit(T->getPointeeType());
6339 bool UnnamedLocalNoLinkageFinder::VisitMemberPointerType(
6340 const MemberPointerType* T) {
6341 return Visit(T->getPointeeType()) || Visit(QualType(T->getClass(), 0));
6344 bool UnnamedLocalNoLinkageFinder::VisitConstantArrayType(
6345 const ConstantArrayType* T) {
6346 return Visit(T->getElementType());
6349 bool UnnamedLocalNoLinkageFinder::VisitIncompleteArrayType(
6350 const IncompleteArrayType* T) {
6351 return Visit(T->getElementType());
6354 bool UnnamedLocalNoLinkageFinder::VisitVariableArrayType(
6355 const VariableArrayType* T) {
6356 return Visit(T->getElementType());
6359 bool UnnamedLocalNoLinkageFinder::VisitDependentSizedArrayType(
6360 const DependentSizedArrayType* T) {
6361 return Visit(T->getElementType());
6364 bool UnnamedLocalNoLinkageFinder::VisitDependentSizedExtVectorType(
6365 const DependentSizedExtVectorType* T) {
6366 return Visit(T->getElementType());
6369 bool UnnamedLocalNoLinkageFinder::VisitDependentSizedMatrixType(
6370 const DependentSizedMatrixType *T) {
6371 return Visit(T->getElementType());
6374 bool UnnamedLocalNoLinkageFinder::VisitDependentAddressSpaceType(
6375 const DependentAddressSpaceType *T) {
6376 return Visit(T->getPointeeType());
6379 bool UnnamedLocalNoLinkageFinder::VisitVectorType(const VectorType* T) {
6380 return Visit(T->getElementType());
6383 bool UnnamedLocalNoLinkageFinder::VisitDependentVectorType(
6384 const DependentVectorType *T) {
6385 return Visit(T->getElementType());
6388 bool UnnamedLocalNoLinkageFinder::VisitExtVectorType(const ExtVectorType* T) {
6389 return Visit(T->getElementType());
6392 bool UnnamedLocalNoLinkageFinder::VisitConstantMatrixType(
6393 const ConstantMatrixType *T) {
6394 return Visit(T->getElementType());
6397 bool UnnamedLocalNoLinkageFinder::VisitFunctionProtoType(
6398 const FunctionProtoType* T) {
6399 for (const auto &A : T->param_types()) {
6400 if (Visit(A))
6401 return true;
6404 return Visit(T->getReturnType());
6407 bool UnnamedLocalNoLinkageFinder::VisitFunctionNoProtoType(
6408 const FunctionNoProtoType* T) {
6409 return Visit(T->getReturnType());
6412 bool UnnamedLocalNoLinkageFinder::VisitUnresolvedUsingType(
6413 const UnresolvedUsingType*) {
6414 return false;
6417 bool UnnamedLocalNoLinkageFinder::VisitTypeOfExprType(const TypeOfExprType*) {
6418 return false;
6421 bool UnnamedLocalNoLinkageFinder::VisitTypeOfType(const TypeOfType* T) {
6422 return Visit(T->getUnmodifiedType());
6425 bool UnnamedLocalNoLinkageFinder::VisitDecltypeType(const DecltypeType*) {
6426 return false;
6429 bool UnnamedLocalNoLinkageFinder::VisitUnaryTransformType(
6430 const UnaryTransformType*) {
6431 return false;
6434 bool UnnamedLocalNoLinkageFinder::VisitAutoType(const AutoType *T) {
6435 return Visit(T->getDeducedType());
6438 bool UnnamedLocalNoLinkageFinder::VisitDeducedTemplateSpecializationType(
6439 const DeducedTemplateSpecializationType *T) {
6440 return Visit(T->getDeducedType());
6443 bool UnnamedLocalNoLinkageFinder::VisitRecordType(const RecordType* T) {
6444 return VisitTagDecl(T->getDecl());
6447 bool UnnamedLocalNoLinkageFinder::VisitEnumType(const EnumType* T) {
6448 return VisitTagDecl(T->getDecl());
6451 bool UnnamedLocalNoLinkageFinder::VisitTemplateTypeParmType(
6452 const TemplateTypeParmType*) {
6453 return false;
6456 bool UnnamedLocalNoLinkageFinder::VisitSubstTemplateTypeParmPackType(
6457 const SubstTemplateTypeParmPackType *) {
6458 return false;
6461 bool UnnamedLocalNoLinkageFinder::VisitTemplateSpecializationType(
6462 const TemplateSpecializationType*) {
6463 return false;
6466 bool UnnamedLocalNoLinkageFinder::VisitInjectedClassNameType(
6467 const InjectedClassNameType* T) {
6468 return VisitTagDecl(T->getDecl());
6471 bool UnnamedLocalNoLinkageFinder::VisitDependentNameType(
6472 const DependentNameType* T) {
6473 return VisitNestedNameSpecifier(T->getQualifier());
6476 bool UnnamedLocalNoLinkageFinder::VisitDependentTemplateSpecializationType(
6477 const DependentTemplateSpecializationType* T) {
6478 if (auto *Q = T->getQualifier())
6479 return VisitNestedNameSpecifier(Q);
6480 return false;
6483 bool UnnamedLocalNoLinkageFinder::VisitPackExpansionType(
6484 const PackExpansionType* T) {
6485 return Visit(T->getPattern());
6488 bool UnnamedLocalNoLinkageFinder::VisitObjCObjectType(const ObjCObjectType *) {
6489 return false;
6492 bool UnnamedLocalNoLinkageFinder::VisitObjCInterfaceType(
6493 const ObjCInterfaceType *) {
6494 return false;
6497 bool UnnamedLocalNoLinkageFinder::VisitObjCObjectPointerType(
6498 const ObjCObjectPointerType *) {
6499 return false;
6502 bool UnnamedLocalNoLinkageFinder::VisitAtomicType(const AtomicType* T) {
6503 return Visit(T->getValueType());
6506 bool UnnamedLocalNoLinkageFinder::VisitPipeType(const PipeType* T) {
6507 return false;
6510 bool UnnamedLocalNoLinkageFinder::VisitBitIntType(const BitIntType *T) {
6511 return false;
6514 bool UnnamedLocalNoLinkageFinder::VisitDependentBitIntType(
6515 const DependentBitIntType *T) {
6516 return false;
6519 bool UnnamedLocalNoLinkageFinder::VisitTagDecl(const TagDecl *Tag) {
6520 if (Tag->getDeclContext()->isFunctionOrMethod()) {
6521 S.Diag(SR.getBegin(),
6522 S.getLangOpts().CPlusPlus11 ?
6523 diag::warn_cxx98_compat_template_arg_local_type :
6524 diag::ext_template_arg_local_type)
6525 << S.Context.getTypeDeclType(Tag) << SR;
6526 return true;
6529 if (!Tag->hasNameForLinkage()) {
6530 S.Diag(SR.getBegin(),
6531 S.getLangOpts().CPlusPlus11 ?
6532 diag::warn_cxx98_compat_template_arg_unnamed_type :
6533 diag::ext_template_arg_unnamed_type) << SR;
6534 S.Diag(Tag->getLocation(), diag::note_template_unnamed_type_here);
6535 return true;
6538 return false;
6541 bool UnnamedLocalNoLinkageFinder::VisitNestedNameSpecifier(
6542 NestedNameSpecifier *NNS) {
6543 assert(NNS);
6544 if (NNS->getPrefix() && VisitNestedNameSpecifier(NNS->getPrefix()))
6545 return true;
6547 switch (NNS->getKind()) {
6548 case NestedNameSpecifier::Identifier:
6549 case NestedNameSpecifier::Namespace:
6550 case NestedNameSpecifier::NamespaceAlias:
6551 case NestedNameSpecifier::Global:
6552 case NestedNameSpecifier::Super:
6553 return false;
6555 case NestedNameSpecifier::TypeSpec:
6556 case NestedNameSpecifier::TypeSpecWithTemplate:
6557 return Visit(QualType(NNS->getAsType(), 0));
6559 llvm_unreachable("Invalid NestedNameSpecifier::Kind!");
6562 /// Check a template argument against its corresponding
6563 /// template type parameter.
6565 /// This routine implements the semantics of C++ [temp.arg.type]. It
6566 /// returns true if an error occurred, and false otherwise.
6567 bool Sema::CheckTemplateArgument(TypeSourceInfo *ArgInfo) {
6568 assert(ArgInfo && "invalid TypeSourceInfo");
6569 QualType Arg = ArgInfo->getType();
6570 SourceRange SR = ArgInfo->getTypeLoc().getSourceRange();
6571 QualType CanonArg = Context.getCanonicalType(Arg);
6573 if (CanonArg->isVariablyModifiedType()) {
6574 return Diag(SR.getBegin(), diag::err_variably_modified_template_arg) << Arg;
6575 } else if (Context.hasSameUnqualifiedType(Arg, Context.OverloadTy)) {
6576 return Diag(SR.getBegin(), diag::err_template_arg_overload_type) << SR;
6579 // C++03 [temp.arg.type]p2:
6580 // A local type, a type with no linkage, an unnamed type or a type
6581 // compounded from any of these types shall not be used as a
6582 // template-argument for a template type-parameter.
6584 // C++11 allows these, and even in C++03 we allow them as an extension with
6585 // a warning.
6586 if (LangOpts.CPlusPlus11 || CanonArg->hasUnnamedOrLocalType()) {
6587 UnnamedLocalNoLinkageFinder Finder(*this, SR);
6588 (void)Finder.Visit(CanonArg);
6591 return false;
6594 enum NullPointerValueKind {
6595 NPV_NotNullPointer,
6596 NPV_NullPointer,
6597 NPV_Error
6600 /// Determine whether the given template argument is a null pointer
6601 /// value of the appropriate type.
6602 static NullPointerValueKind
6603 isNullPointerValueTemplateArgument(Sema &S, NonTypeTemplateParmDecl *Param,
6604 QualType ParamType, Expr *Arg,
6605 Decl *Entity = nullptr) {
6606 if (Arg->isValueDependent() || Arg->isTypeDependent())
6607 return NPV_NotNullPointer;
6609 // dllimport'd entities aren't constant but are available inside of template
6610 // arguments.
6611 if (Entity && Entity->hasAttr<DLLImportAttr>())
6612 return NPV_NotNullPointer;
6614 if (!S.isCompleteType(Arg->getExprLoc(), ParamType))
6615 llvm_unreachable(
6616 "Incomplete parameter type in isNullPointerValueTemplateArgument!");
6618 if (!S.getLangOpts().CPlusPlus11)
6619 return NPV_NotNullPointer;
6621 // Determine whether we have a constant expression.
6622 ExprResult ArgRV = S.DefaultFunctionArrayConversion(Arg);
6623 if (ArgRV.isInvalid())
6624 return NPV_Error;
6625 Arg = ArgRV.get();
6627 Expr::EvalResult EvalResult;
6628 SmallVector<PartialDiagnosticAt, 8> Notes;
6629 EvalResult.Diag = &Notes;
6630 if (!Arg->EvaluateAsRValue(EvalResult, S.Context) ||
6631 EvalResult.HasSideEffects) {
6632 SourceLocation DiagLoc = Arg->getExprLoc();
6634 // If our only note is the usual "invalid subexpression" note, just point
6635 // the caret at its location rather than producing an essentially
6636 // redundant note.
6637 if (Notes.size() == 1 && Notes[0].second.getDiagID() ==
6638 diag::note_invalid_subexpr_in_const_expr) {
6639 DiagLoc = Notes[0].first;
6640 Notes.clear();
6643 S.Diag(DiagLoc, diag::err_template_arg_not_address_constant)
6644 << Arg->getType() << Arg->getSourceRange();
6645 for (unsigned I = 0, N = Notes.size(); I != N; ++I)
6646 S.Diag(Notes[I].first, Notes[I].second);
6648 S.NoteTemplateParameterLocation(*Param);
6649 return NPV_Error;
6652 // C++11 [temp.arg.nontype]p1:
6653 // - an address constant expression of type std::nullptr_t
6654 if (Arg->getType()->isNullPtrType())
6655 return NPV_NullPointer;
6657 // - a constant expression that evaluates to a null pointer value (4.10); or
6658 // - a constant expression that evaluates to a null member pointer value
6659 // (4.11); or
6660 if ((EvalResult.Val.isLValue() && EvalResult.Val.isNullPointer()) ||
6661 (EvalResult.Val.isMemberPointer() &&
6662 !EvalResult.Val.getMemberPointerDecl())) {
6663 // If our expression has an appropriate type, we've succeeded.
6664 bool ObjCLifetimeConversion;
6665 if (S.Context.hasSameUnqualifiedType(Arg->getType(), ParamType) ||
6666 S.IsQualificationConversion(Arg->getType(), ParamType, false,
6667 ObjCLifetimeConversion))
6668 return NPV_NullPointer;
6670 // The types didn't match, but we know we got a null pointer; complain,
6671 // then recover as if the types were correct.
6672 S.Diag(Arg->getExprLoc(), diag::err_template_arg_wrongtype_null_constant)
6673 << Arg->getType() << ParamType << Arg->getSourceRange();
6674 S.NoteTemplateParameterLocation(*Param);
6675 return NPV_NullPointer;
6678 if (EvalResult.Val.isLValue() && !EvalResult.Val.getLValueBase()) {
6679 // We found a pointer that isn't null, but doesn't refer to an object.
6680 // We could just return NPV_NotNullPointer, but we can print a better
6681 // message with the information we have here.
6682 S.Diag(Arg->getExprLoc(), diag::err_template_arg_invalid)
6683 << EvalResult.Val.getAsString(S.Context, ParamType);
6684 S.NoteTemplateParameterLocation(*Param);
6685 return NPV_Error;
6688 // If we don't have a null pointer value, but we do have a NULL pointer
6689 // constant, suggest a cast to the appropriate type.
6690 if (Arg->isNullPointerConstant(S.Context, Expr::NPC_NeverValueDependent)) {
6691 std::string Code = "static_cast<" + ParamType.getAsString() + ">(";
6692 S.Diag(Arg->getExprLoc(), diag::err_template_arg_untyped_null_constant)
6693 << ParamType << FixItHint::CreateInsertion(Arg->getBeginLoc(), Code)
6694 << FixItHint::CreateInsertion(S.getLocForEndOfToken(Arg->getEndLoc()),
6695 ")");
6696 S.NoteTemplateParameterLocation(*Param);
6697 return NPV_NullPointer;
6700 // FIXME: If we ever want to support general, address-constant expressions
6701 // as non-type template arguments, we should return the ExprResult here to
6702 // be interpreted by the caller.
6703 return NPV_NotNullPointer;
6706 /// Checks whether the given template argument is compatible with its
6707 /// template parameter.
6708 static bool CheckTemplateArgumentIsCompatibleWithParameter(
6709 Sema &S, NonTypeTemplateParmDecl *Param, QualType ParamType, Expr *ArgIn,
6710 Expr *Arg, QualType ArgType) {
6711 bool ObjCLifetimeConversion;
6712 if (ParamType->isPointerType() &&
6713 !ParamType->castAs<PointerType>()->getPointeeType()->isFunctionType() &&
6714 S.IsQualificationConversion(ArgType, ParamType, false,
6715 ObjCLifetimeConversion)) {
6716 // For pointer-to-object types, qualification conversions are
6717 // permitted.
6718 } else {
6719 if (const ReferenceType *ParamRef = ParamType->getAs<ReferenceType>()) {
6720 if (!ParamRef->getPointeeType()->isFunctionType()) {
6721 // C++ [temp.arg.nontype]p5b3:
6722 // For a non-type template-parameter of type reference to
6723 // object, no conversions apply. The type referred to by the
6724 // reference may be more cv-qualified than the (otherwise
6725 // identical) type of the template- argument. The
6726 // template-parameter is bound directly to the
6727 // template-argument, which shall be an lvalue.
6729 // FIXME: Other qualifiers?
6730 unsigned ParamQuals = ParamRef->getPointeeType().getCVRQualifiers();
6731 unsigned ArgQuals = ArgType.getCVRQualifiers();
6733 if ((ParamQuals | ArgQuals) != ParamQuals) {
6734 S.Diag(Arg->getBeginLoc(),
6735 diag::err_template_arg_ref_bind_ignores_quals)
6736 << ParamType << Arg->getType() << Arg->getSourceRange();
6737 S.NoteTemplateParameterLocation(*Param);
6738 return true;
6743 // At this point, the template argument refers to an object or
6744 // function with external linkage. We now need to check whether the
6745 // argument and parameter types are compatible.
6746 if (!S.Context.hasSameUnqualifiedType(ArgType,
6747 ParamType.getNonReferenceType())) {
6748 // We can't perform this conversion or binding.
6749 if (ParamType->isReferenceType())
6750 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_no_ref_bind)
6751 << ParamType << ArgIn->getType() << Arg->getSourceRange();
6752 else
6753 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_not_convertible)
6754 << ArgIn->getType() << ParamType << Arg->getSourceRange();
6755 S.NoteTemplateParameterLocation(*Param);
6756 return true;
6760 return false;
6763 /// Checks whether the given template argument is the address
6764 /// of an object or function according to C++ [temp.arg.nontype]p1.
6765 static bool CheckTemplateArgumentAddressOfObjectOrFunction(
6766 Sema &S, NonTypeTemplateParmDecl *Param, QualType ParamType, Expr *ArgIn,
6767 TemplateArgument &SugaredConverted, TemplateArgument &CanonicalConverted) {
6768 bool Invalid = false;
6769 Expr *Arg = ArgIn;
6770 QualType ArgType = Arg->getType();
6772 bool AddressTaken = false;
6773 SourceLocation AddrOpLoc;
6774 if (S.getLangOpts().MicrosoftExt) {
6775 // Microsoft Visual C++ strips all casts, allows an arbitrary number of
6776 // dereference and address-of operators.
6777 Arg = Arg->IgnoreParenCasts();
6779 bool ExtWarnMSTemplateArg = false;
6780 UnaryOperatorKind FirstOpKind;
6781 SourceLocation FirstOpLoc;
6782 while (UnaryOperator *UnOp = dyn_cast<UnaryOperator>(Arg)) {
6783 UnaryOperatorKind UnOpKind = UnOp->getOpcode();
6784 if (UnOpKind == UO_Deref)
6785 ExtWarnMSTemplateArg = true;
6786 if (UnOpKind == UO_AddrOf || UnOpKind == UO_Deref) {
6787 Arg = UnOp->getSubExpr()->IgnoreParenCasts();
6788 if (!AddrOpLoc.isValid()) {
6789 FirstOpKind = UnOpKind;
6790 FirstOpLoc = UnOp->getOperatorLoc();
6792 } else
6793 break;
6795 if (FirstOpLoc.isValid()) {
6796 if (ExtWarnMSTemplateArg)
6797 S.Diag(ArgIn->getBeginLoc(), diag::ext_ms_deref_template_argument)
6798 << ArgIn->getSourceRange();
6800 if (FirstOpKind == UO_AddrOf)
6801 AddressTaken = true;
6802 else if (Arg->getType()->isPointerType()) {
6803 // We cannot let pointers get dereferenced here, that is obviously not a
6804 // constant expression.
6805 assert(FirstOpKind == UO_Deref);
6806 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_not_decl_ref)
6807 << Arg->getSourceRange();
6810 } else {
6811 // See through any implicit casts we added to fix the type.
6812 Arg = Arg->IgnoreImpCasts();
6814 // C++ [temp.arg.nontype]p1:
6816 // A template-argument for a non-type, non-template
6817 // template-parameter shall be one of: [...]
6819 // -- the address of an object or function with external
6820 // linkage, including function templates and function
6821 // template-ids but excluding non-static class members,
6822 // expressed as & id-expression where the & is optional if
6823 // the name refers to a function or array, or if the
6824 // corresponding template-parameter is a reference; or
6826 // In C++98/03 mode, give an extension warning on any extra parentheses.
6827 // See http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#773
6828 bool ExtraParens = false;
6829 while (ParenExpr *Parens = dyn_cast<ParenExpr>(Arg)) {
6830 if (!Invalid && !ExtraParens) {
6831 S.Diag(Arg->getBeginLoc(),
6832 S.getLangOpts().CPlusPlus11
6833 ? diag::warn_cxx98_compat_template_arg_extra_parens
6834 : diag::ext_template_arg_extra_parens)
6835 << Arg->getSourceRange();
6836 ExtraParens = true;
6839 Arg = Parens->getSubExpr();
6842 while (SubstNonTypeTemplateParmExpr *subst =
6843 dyn_cast<SubstNonTypeTemplateParmExpr>(Arg))
6844 Arg = subst->getReplacement()->IgnoreImpCasts();
6846 if (UnaryOperator *UnOp = dyn_cast<UnaryOperator>(Arg)) {
6847 if (UnOp->getOpcode() == UO_AddrOf) {
6848 Arg = UnOp->getSubExpr();
6849 AddressTaken = true;
6850 AddrOpLoc = UnOp->getOperatorLoc();
6854 while (SubstNonTypeTemplateParmExpr *subst =
6855 dyn_cast<SubstNonTypeTemplateParmExpr>(Arg))
6856 Arg = subst->getReplacement()->IgnoreImpCasts();
6859 ValueDecl *Entity = nullptr;
6860 if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Arg))
6861 Entity = DRE->getDecl();
6862 else if (CXXUuidofExpr *CUE = dyn_cast<CXXUuidofExpr>(Arg))
6863 Entity = CUE->getGuidDecl();
6865 // If our parameter has pointer type, check for a null template value.
6866 if (ParamType->isPointerType() || ParamType->isNullPtrType()) {
6867 switch (isNullPointerValueTemplateArgument(S, Param, ParamType, ArgIn,
6868 Entity)) {
6869 case NPV_NullPointer:
6870 S.Diag(Arg->getExprLoc(), diag::warn_cxx98_compat_template_arg_null);
6871 SugaredConverted = TemplateArgument(ParamType,
6872 /*isNullPtr=*/true);
6873 CanonicalConverted =
6874 TemplateArgument(S.Context.getCanonicalType(ParamType),
6875 /*isNullPtr=*/true);
6876 return false;
6878 case NPV_Error:
6879 return true;
6881 case NPV_NotNullPointer:
6882 break;
6886 // Stop checking the precise nature of the argument if it is value dependent,
6887 // it should be checked when instantiated.
6888 if (Arg->isValueDependent()) {
6889 SugaredConverted = TemplateArgument(ArgIn);
6890 CanonicalConverted =
6891 S.Context.getCanonicalTemplateArgument(SugaredConverted);
6892 return false;
6895 if (!Entity) {
6896 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_not_decl_ref)
6897 << Arg->getSourceRange();
6898 S.NoteTemplateParameterLocation(*Param);
6899 return true;
6902 // Cannot refer to non-static data members
6903 if (isa<FieldDecl>(Entity) || isa<IndirectFieldDecl>(Entity)) {
6904 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_field)
6905 << Entity << Arg->getSourceRange();
6906 S.NoteTemplateParameterLocation(*Param);
6907 return true;
6910 // Cannot refer to non-static member functions
6911 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Entity)) {
6912 if (!Method->isStatic()) {
6913 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_method)
6914 << Method << Arg->getSourceRange();
6915 S.NoteTemplateParameterLocation(*Param);
6916 return true;
6920 FunctionDecl *Func = dyn_cast<FunctionDecl>(Entity);
6921 VarDecl *Var = dyn_cast<VarDecl>(Entity);
6922 MSGuidDecl *Guid = dyn_cast<MSGuidDecl>(Entity);
6924 // A non-type template argument must refer to an object or function.
6925 if (!Func && !Var && !Guid) {
6926 // We found something, but we don't know specifically what it is.
6927 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_not_object_or_func)
6928 << Arg->getSourceRange();
6929 S.Diag(Entity->getLocation(), diag::note_template_arg_refers_here);
6930 return true;
6933 // Address / reference template args must have external linkage in C++98.
6934 if (Entity->getFormalLinkage() == Linkage::Internal) {
6935 S.Diag(Arg->getBeginLoc(),
6936 S.getLangOpts().CPlusPlus11
6937 ? diag::warn_cxx98_compat_template_arg_object_internal
6938 : diag::ext_template_arg_object_internal)
6939 << !Func << Entity << Arg->getSourceRange();
6940 S.Diag(Entity->getLocation(), diag::note_template_arg_internal_object)
6941 << !Func;
6942 } else if (!Entity->hasLinkage()) {
6943 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_object_no_linkage)
6944 << !Func << Entity << Arg->getSourceRange();
6945 S.Diag(Entity->getLocation(), diag::note_template_arg_internal_object)
6946 << !Func;
6947 return true;
6950 if (Var) {
6951 // A value of reference type is not an object.
6952 if (Var->getType()->isReferenceType()) {
6953 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_reference_var)
6954 << Var->getType() << Arg->getSourceRange();
6955 S.NoteTemplateParameterLocation(*Param);
6956 return true;
6959 // A template argument must have static storage duration.
6960 if (Var->getTLSKind()) {
6961 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_thread_local)
6962 << Arg->getSourceRange();
6963 S.Diag(Var->getLocation(), diag::note_template_arg_refers_here);
6964 return true;
6968 if (AddressTaken && ParamType->isReferenceType()) {
6969 // If we originally had an address-of operator, but the
6970 // parameter has reference type, complain and (if things look
6971 // like they will work) drop the address-of operator.
6972 if (!S.Context.hasSameUnqualifiedType(Entity->getType(),
6973 ParamType.getNonReferenceType())) {
6974 S.Diag(AddrOpLoc, diag::err_template_arg_address_of_non_pointer)
6975 << ParamType;
6976 S.NoteTemplateParameterLocation(*Param);
6977 return true;
6980 S.Diag(AddrOpLoc, diag::err_template_arg_address_of_non_pointer)
6981 << ParamType
6982 << FixItHint::CreateRemoval(AddrOpLoc);
6983 S.NoteTemplateParameterLocation(*Param);
6985 ArgType = Entity->getType();
6988 // If the template parameter has pointer type, either we must have taken the
6989 // address or the argument must decay to a pointer.
6990 if (!AddressTaken && ParamType->isPointerType()) {
6991 if (Func) {
6992 // Function-to-pointer decay.
6993 ArgType = S.Context.getPointerType(Func->getType());
6994 } else if (Entity->getType()->isArrayType()) {
6995 // Array-to-pointer decay.
6996 ArgType = S.Context.getArrayDecayedType(Entity->getType());
6997 } else {
6998 // If the template parameter has pointer type but the address of
6999 // this object was not taken, complain and (possibly) recover by
7000 // taking the address of the entity.
7001 ArgType = S.Context.getPointerType(Entity->getType());
7002 if (!S.Context.hasSameUnqualifiedType(ArgType, ParamType)) {
7003 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_not_address_of)
7004 << ParamType;
7005 S.NoteTemplateParameterLocation(*Param);
7006 return true;
7009 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_not_address_of)
7010 << ParamType << FixItHint::CreateInsertion(Arg->getBeginLoc(), "&");
7012 S.NoteTemplateParameterLocation(*Param);
7016 if (CheckTemplateArgumentIsCompatibleWithParameter(S, Param, ParamType, ArgIn,
7017 Arg, ArgType))
7018 return true;
7020 // Create the template argument.
7021 SugaredConverted = TemplateArgument(Entity, ParamType);
7022 CanonicalConverted =
7023 TemplateArgument(cast<ValueDecl>(Entity->getCanonicalDecl()),
7024 S.Context.getCanonicalType(ParamType));
7025 S.MarkAnyDeclReferenced(Arg->getBeginLoc(), Entity, false);
7026 return false;
7029 /// Checks whether the given template argument is a pointer to
7030 /// member constant according to C++ [temp.arg.nontype]p1.
7031 static bool
7032 CheckTemplateArgumentPointerToMember(Sema &S, NonTypeTemplateParmDecl *Param,
7033 QualType ParamType, Expr *&ResultArg,
7034 TemplateArgument &SugaredConverted,
7035 TemplateArgument &CanonicalConverted) {
7036 bool Invalid = false;
7038 Expr *Arg = ResultArg;
7039 bool ObjCLifetimeConversion;
7041 // C++ [temp.arg.nontype]p1:
7043 // A template-argument for a non-type, non-template
7044 // template-parameter shall be one of: [...]
7046 // -- a pointer to member expressed as described in 5.3.1.
7047 DeclRefExpr *DRE = nullptr;
7049 // In C++98/03 mode, give an extension warning on any extra parentheses.
7050 // See http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#773
7051 bool ExtraParens = false;
7052 while (ParenExpr *Parens = dyn_cast<ParenExpr>(Arg)) {
7053 if (!Invalid && !ExtraParens) {
7054 S.Diag(Arg->getBeginLoc(),
7055 S.getLangOpts().CPlusPlus11
7056 ? diag::warn_cxx98_compat_template_arg_extra_parens
7057 : diag::ext_template_arg_extra_parens)
7058 << Arg->getSourceRange();
7059 ExtraParens = true;
7062 Arg = Parens->getSubExpr();
7065 while (SubstNonTypeTemplateParmExpr *subst =
7066 dyn_cast<SubstNonTypeTemplateParmExpr>(Arg))
7067 Arg = subst->getReplacement()->IgnoreImpCasts();
7069 // A pointer-to-member constant written &Class::member.
7070 if (UnaryOperator *UnOp = dyn_cast<UnaryOperator>(Arg)) {
7071 if (UnOp->getOpcode() == UO_AddrOf) {
7072 DRE = dyn_cast<DeclRefExpr>(UnOp->getSubExpr());
7073 if (DRE && !DRE->getQualifier())
7074 DRE = nullptr;
7077 // A constant of pointer-to-member type.
7078 else if ((DRE = dyn_cast<DeclRefExpr>(Arg))) {
7079 ValueDecl *VD = DRE->getDecl();
7080 if (VD->getType()->isMemberPointerType()) {
7081 if (isa<NonTypeTemplateParmDecl>(VD)) {
7082 if (Arg->isTypeDependent() || Arg->isValueDependent()) {
7083 SugaredConverted = TemplateArgument(Arg);
7084 CanonicalConverted =
7085 S.Context.getCanonicalTemplateArgument(SugaredConverted);
7086 } else {
7087 SugaredConverted = TemplateArgument(VD, ParamType);
7088 CanonicalConverted =
7089 TemplateArgument(cast<ValueDecl>(VD->getCanonicalDecl()),
7090 S.Context.getCanonicalType(ParamType));
7092 return Invalid;
7096 DRE = nullptr;
7099 ValueDecl *Entity = DRE ? DRE->getDecl() : nullptr;
7101 // Check for a null pointer value.
7102 switch (isNullPointerValueTemplateArgument(S, Param, ParamType, ResultArg,
7103 Entity)) {
7104 case NPV_Error:
7105 return true;
7106 case NPV_NullPointer:
7107 S.Diag(ResultArg->getExprLoc(), diag::warn_cxx98_compat_template_arg_null);
7108 SugaredConverted = TemplateArgument(ParamType,
7109 /*isNullPtr*/ true);
7110 CanonicalConverted = TemplateArgument(S.Context.getCanonicalType(ParamType),
7111 /*isNullPtr*/ true);
7112 return false;
7113 case NPV_NotNullPointer:
7114 break;
7117 if (S.IsQualificationConversion(ResultArg->getType(),
7118 ParamType.getNonReferenceType(), false,
7119 ObjCLifetimeConversion)) {
7120 ResultArg = S.ImpCastExprToType(ResultArg, ParamType, CK_NoOp,
7121 ResultArg->getValueKind())
7122 .get();
7123 } else if (!S.Context.hasSameUnqualifiedType(
7124 ResultArg->getType(), ParamType.getNonReferenceType())) {
7125 // We can't perform this conversion.
7126 S.Diag(ResultArg->getBeginLoc(), diag::err_template_arg_not_convertible)
7127 << ResultArg->getType() << ParamType << ResultArg->getSourceRange();
7128 S.NoteTemplateParameterLocation(*Param);
7129 return true;
7132 if (!DRE)
7133 return S.Diag(Arg->getBeginLoc(),
7134 diag::err_template_arg_not_pointer_to_member_form)
7135 << Arg->getSourceRange();
7137 if (isa<FieldDecl>(DRE->getDecl()) ||
7138 isa<IndirectFieldDecl>(DRE->getDecl()) ||
7139 isa<CXXMethodDecl>(DRE->getDecl())) {
7140 assert((isa<FieldDecl>(DRE->getDecl()) ||
7141 isa<IndirectFieldDecl>(DRE->getDecl()) ||
7142 cast<CXXMethodDecl>(DRE->getDecl())
7143 ->isImplicitObjectMemberFunction()) &&
7144 "Only non-static member pointers can make it here");
7146 // Okay: this is the address of a non-static member, and therefore
7147 // a member pointer constant.
7148 if (Arg->isTypeDependent() || Arg->isValueDependent()) {
7149 SugaredConverted = TemplateArgument(Arg);
7150 CanonicalConverted =
7151 S.Context.getCanonicalTemplateArgument(SugaredConverted);
7152 } else {
7153 ValueDecl *D = DRE->getDecl();
7154 SugaredConverted = TemplateArgument(D, ParamType);
7155 CanonicalConverted =
7156 TemplateArgument(cast<ValueDecl>(D->getCanonicalDecl()),
7157 S.Context.getCanonicalType(ParamType));
7159 return Invalid;
7162 // We found something else, but we don't know specifically what it is.
7163 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_not_pointer_to_member_form)
7164 << Arg->getSourceRange();
7165 S.Diag(DRE->getDecl()->getLocation(), diag::note_template_arg_refers_here);
7166 return true;
7169 /// Check a template argument against its corresponding
7170 /// non-type template parameter.
7172 /// This routine implements the semantics of C++ [temp.arg.nontype].
7173 /// If an error occurred, it returns ExprError(); otherwise, it
7174 /// returns the converted template argument. \p ParamType is the
7175 /// type of the non-type template parameter after it has been instantiated.
7176 ExprResult Sema::CheckTemplateArgument(NonTypeTemplateParmDecl *Param,
7177 QualType ParamType, Expr *Arg,
7178 TemplateArgument &SugaredConverted,
7179 TemplateArgument &CanonicalConverted,
7180 CheckTemplateArgumentKind CTAK) {
7181 SourceLocation StartLoc = Arg->getBeginLoc();
7183 // If the parameter type somehow involves auto, deduce the type now.
7184 DeducedType *DeducedT = ParamType->getContainedDeducedType();
7185 if (getLangOpts().CPlusPlus17 && DeducedT && !DeducedT->isDeduced()) {
7186 // During template argument deduction, we allow 'decltype(auto)' to
7187 // match an arbitrary dependent argument.
7188 // FIXME: The language rules don't say what happens in this case.
7189 // FIXME: We get an opaque dependent type out of decltype(auto) if the
7190 // expression is merely instantiation-dependent; is this enough?
7191 if (CTAK == CTAK_Deduced && Arg->isTypeDependent()) {
7192 auto *AT = dyn_cast<AutoType>(DeducedT);
7193 if (AT && AT->isDecltypeAuto()) {
7194 SugaredConverted = TemplateArgument(Arg);
7195 CanonicalConverted = TemplateArgument(
7196 Context.getCanonicalTemplateArgument(SugaredConverted));
7197 return Arg;
7201 // When checking a deduced template argument, deduce from its type even if
7202 // the type is dependent, in order to check the types of non-type template
7203 // arguments line up properly in partial ordering.
7204 Expr *DeductionArg = Arg;
7205 if (auto *PE = dyn_cast<PackExpansionExpr>(DeductionArg))
7206 DeductionArg = PE->getPattern();
7207 TypeSourceInfo *TSI =
7208 Context.getTrivialTypeSourceInfo(ParamType, Param->getLocation());
7209 if (isa<DeducedTemplateSpecializationType>(DeducedT)) {
7210 InitializedEntity Entity =
7211 InitializedEntity::InitializeTemplateParameter(ParamType, Param);
7212 InitializationKind Kind = InitializationKind::CreateForInit(
7213 DeductionArg->getBeginLoc(), /*DirectInit*/false, DeductionArg);
7214 Expr *Inits[1] = {DeductionArg};
7215 ParamType =
7216 DeduceTemplateSpecializationFromInitializer(TSI, Entity, Kind, Inits);
7217 if (ParamType.isNull())
7218 return ExprError();
7219 } else {
7220 TemplateDeductionInfo Info(DeductionArg->getExprLoc(),
7221 Param->getDepth() + 1);
7222 ParamType = QualType();
7223 TemplateDeductionResult Result =
7224 DeduceAutoType(TSI->getTypeLoc(), DeductionArg, ParamType, Info,
7225 /*DependentDeduction=*/true,
7226 // We do not check constraints right now because the
7227 // immediately-declared constraint of the auto type is
7228 // also an associated constraint, and will be checked
7229 // along with the other associated constraints after
7230 // checking the template argument list.
7231 /*IgnoreConstraints=*/true);
7232 if (Result == TDK_AlreadyDiagnosed) {
7233 if (ParamType.isNull())
7234 return ExprError();
7235 } else if (Result != TDK_Success) {
7236 Diag(Arg->getExprLoc(),
7237 diag::err_non_type_template_parm_type_deduction_failure)
7238 << Param->getDeclName() << Param->getType() << Arg->getType()
7239 << Arg->getSourceRange();
7240 NoteTemplateParameterLocation(*Param);
7241 return ExprError();
7244 // CheckNonTypeTemplateParameterType will produce a diagnostic if there's
7245 // an error. The error message normally references the parameter
7246 // declaration, but here we'll pass the argument location because that's
7247 // where the parameter type is deduced.
7248 ParamType = CheckNonTypeTemplateParameterType(ParamType, Arg->getExprLoc());
7249 if (ParamType.isNull()) {
7250 NoteTemplateParameterLocation(*Param);
7251 return ExprError();
7255 // We should have already dropped all cv-qualifiers by now.
7256 assert(!ParamType.hasQualifiers() &&
7257 "non-type template parameter type cannot be qualified");
7259 // FIXME: When Param is a reference, should we check that Arg is an lvalue?
7260 if (CTAK == CTAK_Deduced &&
7261 (ParamType->isReferenceType()
7262 ? !Context.hasSameType(ParamType.getNonReferenceType(),
7263 Arg->getType())
7264 : !Context.hasSameUnqualifiedType(ParamType, Arg->getType()))) {
7265 // FIXME: If either type is dependent, we skip the check. This isn't
7266 // correct, since during deduction we're supposed to have replaced each
7267 // template parameter with some unique (non-dependent) placeholder.
7268 // FIXME: If the argument type contains 'auto', we carry on and fail the
7269 // type check in order to force specific types to be more specialized than
7270 // 'auto'. It's not clear how partial ordering with 'auto' is supposed to
7271 // work. Similarly for CTAD, when comparing 'A<x>' against 'A'.
7272 if ((ParamType->isDependentType() || Arg->isTypeDependent()) &&
7273 !Arg->getType()->getContainedDeducedType()) {
7274 SugaredConverted = TemplateArgument(Arg);
7275 CanonicalConverted = TemplateArgument(
7276 Context.getCanonicalTemplateArgument(SugaredConverted));
7277 return Arg;
7279 // FIXME: This attempts to implement C++ [temp.deduct.type]p17. Per DR1770,
7280 // we should actually be checking the type of the template argument in P,
7281 // not the type of the template argument deduced from A, against the
7282 // template parameter type.
7283 Diag(StartLoc, diag::err_deduced_non_type_template_arg_type_mismatch)
7284 << Arg->getType()
7285 << ParamType.getUnqualifiedType();
7286 NoteTemplateParameterLocation(*Param);
7287 return ExprError();
7290 // If either the parameter has a dependent type or the argument is
7291 // type-dependent, there's nothing we can check now.
7292 if (ParamType->isDependentType() || Arg->isTypeDependent()) {
7293 // Force the argument to the type of the parameter to maintain invariants.
7294 auto *PE = dyn_cast<PackExpansionExpr>(Arg);
7295 if (PE)
7296 Arg = PE->getPattern();
7297 ExprResult E = ImpCastExprToType(
7298 Arg, ParamType.getNonLValueExprType(Context), CK_Dependent,
7299 ParamType->isLValueReferenceType() ? VK_LValue
7300 : ParamType->isRValueReferenceType() ? VK_XValue
7301 : VK_PRValue);
7302 if (E.isInvalid())
7303 return ExprError();
7304 if (PE) {
7305 // Recreate a pack expansion if we unwrapped one.
7306 E = new (Context)
7307 PackExpansionExpr(E.get()->getType(), E.get(), PE->getEllipsisLoc(),
7308 PE->getNumExpansions());
7310 SugaredConverted = TemplateArgument(E.get());
7311 CanonicalConverted = TemplateArgument(
7312 Context.getCanonicalTemplateArgument(SugaredConverted));
7313 return E;
7316 QualType CanonParamType = Context.getCanonicalType(ParamType);
7317 // Avoid making a copy when initializing a template parameter of class type
7318 // from a template parameter object of the same type. This is going beyond
7319 // the standard, but is required for soundness: in
7320 // template<A a> struct X { X *p; X<a> *q; };
7321 // ... we need p and q to have the same type.
7323 // Similarly, don't inject a call to a copy constructor when initializing
7324 // from a template parameter of the same type.
7325 Expr *InnerArg = Arg->IgnoreParenImpCasts();
7326 if (ParamType->isRecordType() && isa<DeclRefExpr>(InnerArg) &&
7327 Context.hasSameUnqualifiedType(ParamType, InnerArg->getType())) {
7328 NamedDecl *ND = cast<DeclRefExpr>(InnerArg)->getDecl();
7329 if (auto *TPO = dyn_cast<TemplateParamObjectDecl>(ND)) {
7331 SugaredConverted = TemplateArgument(TPO, ParamType);
7332 CanonicalConverted =
7333 TemplateArgument(TPO->getCanonicalDecl(), CanonParamType);
7334 return Arg;
7336 if (isa<NonTypeTemplateParmDecl>(ND)) {
7337 SugaredConverted = TemplateArgument(Arg);
7338 CanonicalConverted =
7339 Context.getCanonicalTemplateArgument(SugaredConverted);
7340 return Arg;
7344 // The initialization of the parameter from the argument is
7345 // a constant-evaluated context.
7346 EnterExpressionEvaluationContext ConstantEvaluated(
7347 *this, Sema::ExpressionEvaluationContext::ConstantEvaluated);
7349 bool IsConvertedConstantExpression = true;
7350 if (isa<InitListExpr>(Arg) || ParamType->isRecordType()) {
7351 InitializationKind Kind = InitializationKind::CreateForInit(
7352 Arg->getBeginLoc(), /*DirectInit=*/false, Arg);
7353 Expr *Inits[1] = {Arg};
7354 InitializedEntity Entity =
7355 InitializedEntity::InitializeTemplateParameter(ParamType, Param);
7356 InitializationSequence InitSeq(*this, Entity, Kind, Inits);
7357 ExprResult Result = InitSeq.Perform(*this, Entity, Kind, Inits);
7358 if (Result.isInvalid() || !Result.get())
7359 return ExprError();
7360 Result = ActOnConstantExpression(Result.get());
7361 if (Result.isInvalid() || !Result.get())
7362 return ExprError();
7363 Arg = ActOnFinishFullExpr(Result.get(), Arg->getBeginLoc(),
7364 /*DiscardedValue=*/false,
7365 /*IsConstexpr=*/true, /*IsTemplateArgument=*/true)
7366 .get();
7367 IsConvertedConstantExpression = false;
7370 if (getLangOpts().CPlusPlus17) {
7371 // C++17 [temp.arg.nontype]p1:
7372 // A template-argument for a non-type template parameter shall be
7373 // a converted constant expression of the type of the template-parameter.
7374 APValue Value;
7375 ExprResult ArgResult;
7376 if (IsConvertedConstantExpression) {
7377 ArgResult = BuildConvertedConstantExpression(Arg, ParamType,
7378 CCEK_TemplateArg, Param);
7379 if (ArgResult.isInvalid())
7380 return ExprError();
7381 } else {
7382 ArgResult = Arg;
7385 // For a value-dependent argument, CheckConvertedConstantExpression is
7386 // permitted (and expected) to be unable to determine a value.
7387 if (ArgResult.get()->isValueDependent()) {
7388 SugaredConverted = TemplateArgument(ArgResult.get());
7389 CanonicalConverted =
7390 Context.getCanonicalTemplateArgument(SugaredConverted);
7391 return ArgResult;
7394 APValue PreNarrowingValue;
7395 ArgResult = EvaluateConvertedConstantExpression(
7396 ArgResult.get(), ParamType, Value, CCEK_TemplateArg, /*RequireInt=*/
7397 false, PreNarrowingValue);
7398 if (ArgResult.isInvalid())
7399 return ExprError();
7401 // Convert the APValue to a TemplateArgument.
7402 switch (Value.getKind()) {
7403 case APValue::None:
7404 assert(ParamType->isNullPtrType());
7405 SugaredConverted = TemplateArgument(ParamType, /*isNullPtr=*/true);
7406 CanonicalConverted = TemplateArgument(CanonParamType, /*isNullPtr=*/true);
7407 break;
7408 case APValue::Indeterminate:
7409 llvm_unreachable("result of constant evaluation should be initialized");
7410 break;
7411 case APValue::Int:
7412 assert(ParamType->isIntegralOrEnumerationType());
7413 SugaredConverted = TemplateArgument(Context, Value.getInt(), ParamType);
7414 CanonicalConverted =
7415 TemplateArgument(Context, Value.getInt(), CanonParamType);
7416 break;
7417 case APValue::MemberPointer: {
7418 assert(ParamType->isMemberPointerType());
7420 // FIXME: We need TemplateArgument representation and mangling for these.
7421 if (!Value.getMemberPointerPath().empty()) {
7422 Diag(Arg->getBeginLoc(),
7423 diag::err_template_arg_member_ptr_base_derived_not_supported)
7424 << Value.getMemberPointerDecl() << ParamType
7425 << Arg->getSourceRange();
7426 return ExprError();
7429 auto *VD = const_cast<ValueDecl*>(Value.getMemberPointerDecl());
7430 SugaredConverted = VD ? TemplateArgument(VD, ParamType)
7431 : TemplateArgument(ParamType, /*isNullPtr=*/true);
7432 CanonicalConverted =
7433 VD ? TemplateArgument(cast<ValueDecl>(VD->getCanonicalDecl()),
7434 CanonParamType)
7435 : TemplateArgument(CanonParamType, /*isNullPtr=*/true);
7436 break;
7438 case APValue::LValue: {
7439 // For a non-type template-parameter of pointer or reference type,
7440 // the value of the constant expression shall not refer to
7441 assert(ParamType->isPointerType() || ParamType->isReferenceType() ||
7442 ParamType->isNullPtrType());
7443 // -- a temporary object
7444 // -- a string literal
7445 // -- the result of a typeid expression, or
7446 // -- a predefined __func__ variable
7447 APValue::LValueBase Base = Value.getLValueBase();
7448 auto *VD = const_cast<ValueDecl *>(Base.dyn_cast<const ValueDecl *>());
7449 if (Base &&
7450 (!VD ||
7451 isa<LifetimeExtendedTemporaryDecl, UnnamedGlobalConstantDecl>(VD))) {
7452 Diag(Arg->getBeginLoc(), diag::err_template_arg_not_decl_ref)
7453 << Arg->getSourceRange();
7454 return ExprError();
7456 // -- a subobject
7457 // FIXME: Until C++20
7458 if (Value.hasLValuePath() && Value.getLValuePath().size() == 1 &&
7459 VD && VD->getType()->isArrayType() &&
7460 Value.getLValuePath()[0].getAsArrayIndex() == 0 &&
7461 !Value.isLValueOnePastTheEnd() && ParamType->isPointerType()) {
7462 // Per defect report (no number yet):
7463 // ... other than a pointer to the first element of a complete array
7464 // object.
7465 } else if (!Value.hasLValuePath() || Value.getLValuePath().size() ||
7466 Value.isLValueOnePastTheEnd()) {
7467 Diag(StartLoc, diag::err_non_type_template_arg_subobject)
7468 << Value.getAsString(Context, ParamType);
7469 return ExprError();
7471 assert((VD || !ParamType->isReferenceType()) &&
7472 "null reference should not be a constant expression");
7473 assert((!VD || !ParamType->isNullPtrType()) &&
7474 "non-null value of type nullptr_t?");
7476 SugaredConverted = VD ? TemplateArgument(VD, ParamType)
7477 : TemplateArgument(ParamType, /*isNullPtr=*/true);
7478 CanonicalConverted =
7479 VD ? TemplateArgument(cast<ValueDecl>(VD->getCanonicalDecl()),
7480 CanonParamType)
7481 : TemplateArgument(CanonParamType, /*isNullPtr=*/true);
7482 break;
7484 case APValue::Struct:
7485 case APValue::Union: {
7486 // Get or create the corresponding template parameter object.
7487 TemplateParamObjectDecl *D =
7488 Context.getTemplateParamObjectDecl(ParamType, Value);
7489 SugaredConverted = TemplateArgument(D, ParamType);
7490 CanonicalConverted =
7491 TemplateArgument(D->getCanonicalDecl(), CanonParamType);
7492 break;
7494 case APValue::AddrLabelDiff:
7495 return Diag(StartLoc, diag::err_non_type_template_arg_addr_label_diff);
7496 case APValue::FixedPoint:
7497 case APValue::Float:
7498 case APValue::ComplexInt:
7499 case APValue::ComplexFloat:
7500 case APValue::Vector:
7501 case APValue::Array:
7502 return Diag(StartLoc, diag::err_non_type_template_arg_unsupported)
7503 << ParamType;
7506 return ArgResult.get();
7509 // C++ [temp.arg.nontype]p5:
7510 // The following conversions are performed on each expression used
7511 // as a non-type template-argument. If a non-type
7512 // template-argument cannot be converted to the type of the
7513 // corresponding template-parameter then the program is
7514 // ill-formed.
7515 if (ParamType->isIntegralOrEnumerationType()) {
7516 // C++11:
7517 // -- for a non-type template-parameter of integral or
7518 // enumeration type, conversions permitted in a converted
7519 // constant expression are applied.
7521 // C++98:
7522 // -- for a non-type template-parameter of integral or
7523 // enumeration type, integral promotions (4.5) and integral
7524 // conversions (4.7) are applied.
7526 if (getLangOpts().CPlusPlus11) {
7527 // C++ [temp.arg.nontype]p1:
7528 // A template-argument for a non-type, non-template template-parameter
7529 // shall be one of:
7531 // -- for a non-type template-parameter of integral or enumeration
7532 // type, a converted constant expression of the type of the
7533 // template-parameter; or
7534 llvm::APSInt Value;
7535 ExprResult ArgResult =
7536 CheckConvertedConstantExpression(Arg, ParamType, Value,
7537 CCEK_TemplateArg);
7538 if (ArgResult.isInvalid())
7539 return ExprError();
7541 // We can't check arbitrary value-dependent arguments.
7542 if (ArgResult.get()->isValueDependent()) {
7543 SugaredConverted = TemplateArgument(ArgResult.get());
7544 CanonicalConverted =
7545 Context.getCanonicalTemplateArgument(SugaredConverted);
7546 return ArgResult;
7549 // Widen the argument value to sizeof(parameter type). This is almost
7550 // always a no-op, except when the parameter type is bool. In
7551 // that case, this may extend the argument from 1 bit to 8 bits.
7552 QualType IntegerType = ParamType;
7553 if (const EnumType *Enum = IntegerType->getAs<EnumType>())
7554 IntegerType = Enum->getDecl()->getIntegerType();
7555 Value = Value.extOrTrunc(IntegerType->isBitIntType()
7556 ? Context.getIntWidth(IntegerType)
7557 : Context.getTypeSize(IntegerType));
7559 SugaredConverted = TemplateArgument(Context, Value, ParamType);
7560 CanonicalConverted =
7561 TemplateArgument(Context, Value, Context.getCanonicalType(ParamType));
7562 return ArgResult;
7565 ExprResult ArgResult = DefaultLvalueConversion(Arg);
7566 if (ArgResult.isInvalid())
7567 return ExprError();
7568 Arg = ArgResult.get();
7570 QualType ArgType = Arg->getType();
7572 // C++ [temp.arg.nontype]p1:
7573 // A template-argument for a non-type, non-template
7574 // template-parameter shall be one of:
7576 // -- an integral constant-expression of integral or enumeration
7577 // type; or
7578 // -- the name of a non-type template-parameter; or
7579 llvm::APSInt Value;
7580 if (!ArgType->isIntegralOrEnumerationType()) {
7581 Diag(Arg->getBeginLoc(), diag::err_template_arg_not_integral_or_enumeral)
7582 << ArgType << Arg->getSourceRange();
7583 NoteTemplateParameterLocation(*Param);
7584 return ExprError();
7585 } else if (!Arg->isValueDependent()) {
7586 class TmplArgICEDiagnoser : public VerifyICEDiagnoser {
7587 QualType T;
7589 public:
7590 TmplArgICEDiagnoser(QualType T) : T(T) { }
7592 SemaDiagnosticBuilder diagnoseNotICE(Sema &S,
7593 SourceLocation Loc) override {
7594 return S.Diag(Loc, diag::err_template_arg_not_ice) << T;
7596 } Diagnoser(ArgType);
7598 Arg = VerifyIntegerConstantExpression(Arg, &Value, Diagnoser).get();
7599 if (!Arg)
7600 return ExprError();
7603 // From here on out, all we care about is the unqualified form
7604 // of the argument type.
7605 ArgType = ArgType.getUnqualifiedType();
7607 // Try to convert the argument to the parameter's type.
7608 if (Context.hasSameType(ParamType, ArgType)) {
7609 // Okay: no conversion necessary
7610 } else if (ParamType->isBooleanType()) {
7611 // This is an integral-to-boolean conversion.
7612 Arg = ImpCastExprToType(Arg, ParamType, CK_IntegralToBoolean).get();
7613 } else if (IsIntegralPromotion(Arg, ArgType, ParamType) ||
7614 !ParamType->isEnumeralType()) {
7615 // This is an integral promotion or conversion.
7616 Arg = ImpCastExprToType(Arg, ParamType, CK_IntegralCast).get();
7617 } else {
7618 // We can't perform this conversion.
7619 Diag(Arg->getBeginLoc(), diag::err_template_arg_not_convertible)
7620 << Arg->getType() << ParamType << Arg->getSourceRange();
7621 NoteTemplateParameterLocation(*Param);
7622 return ExprError();
7625 // Add the value of this argument to the list of converted
7626 // arguments. We use the bitwidth and signedness of the template
7627 // parameter.
7628 if (Arg->isValueDependent()) {
7629 // The argument is value-dependent. Create a new
7630 // TemplateArgument with the converted expression.
7631 SugaredConverted = TemplateArgument(Arg);
7632 CanonicalConverted =
7633 Context.getCanonicalTemplateArgument(SugaredConverted);
7634 return Arg;
7637 QualType IntegerType = ParamType;
7638 if (const EnumType *Enum = IntegerType->getAs<EnumType>()) {
7639 IntegerType = Enum->getDecl()->getIntegerType();
7642 if (ParamType->isBooleanType()) {
7643 // Value must be zero or one.
7644 Value = Value != 0;
7645 unsigned AllowedBits = Context.getTypeSize(IntegerType);
7646 if (Value.getBitWidth() != AllowedBits)
7647 Value = Value.extOrTrunc(AllowedBits);
7648 Value.setIsSigned(IntegerType->isSignedIntegerOrEnumerationType());
7649 } else {
7650 llvm::APSInt OldValue = Value;
7652 // Coerce the template argument's value to the value it will have
7653 // based on the template parameter's type.
7654 unsigned AllowedBits = IntegerType->isBitIntType()
7655 ? Context.getIntWidth(IntegerType)
7656 : Context.getTypeSize(IntegerType);
7657 if (Value.getBitWidth() != AllowedBits)
7658 Value = Value.extOrTrunc(AllowedBits);
7659 Value.setIsSigned(IntegerType->isSignedIntegerOrEnumerationType());
7661 // Complain if an unsigned parameter received a negative value.
7662 if (IntegerType->isUnsignedIntegerOrEnumerationType() &&
7663 (OldValue.isSigned() && OldValue.isNegative())) {
7664 Diag(Arg->getBeginLoc(), diag::warn_template_arg_negative)
7665 << toString(OldValue, 10) << toString(Value, 10) << Param->getType()
7666 << Arg->getSourceRange();
7667 NoteTemplateParameterLocation(*Param);
7670 // Complain if we overflowed the template parameter's type.
7671 unsigned RequiredBits;
7672 if (IntegerType->isUnsignedIntegerOrEnumerationType())
7673 RequiredBits = OldValue.getActiveBits();
7674 else if (OldValue.isUnsigned())
7675 RequiredBits = OldValue.getActiveBits() + 1;
7676 else
7677 RequiredBits = OldValue.getSignificantBits();
7678 if (RequiredBits > AllowedBits) {
7679 Diag(Arg->getBeginLoc(), diag::warn_template_arg_too_large)
7680 << toString(OldValue, 10) << toString(Value, 10) << Param->getType()
7681 << Arg->getSourceRange();
7682 NoteTemplateParameterLocation(*Param);
7686 QualType T = ParamType->isEnumeralType() ? ParamType : IntegerType;
7687 SugaredConverted = TemplateArgument(Context, Value, T);
7688 CanonicalConverted =
7689 TemplateArgument(Context, Value, Context.getCanonicalType(T));
7690 return Arg;
7693 QualType ArgType = Arg->getType();
7694 DeclAccessPair FoundResult; // temporary for ResolveOverloadedFunction
7696 // Handle pointer-to-function, reference-to-function, and
7697 // pointer-to-member-function all in (roughly) the same way.
7698 if (// -- For a non-type template-parameter of type pointer to
7699 // function, only the function-to-pointer conversion (4.3) is
7700 // applied. If the template-argument represents a set of
7701 // overloaded functions (or a pointer to such), the matching
7702 // function is selected from the set (13.4).
7703 (ParamType->isPointerType() &&
7704 ParamType->castAs<PointerType>()->getPointeeType()->isFunctionType()) ||
7705 // -- For a non-type template-parameter of type reference to
7706 // function, no conversions apply. If the template-argument
7707 // represents a set of overloaded functions, the matching
7708 // function is selected from the set (13.4).
7709 (ParamType->isReferenceType() &&
7710 ParamType->castAs<ReferenceType>()->getPointeeType()->isFunctionType()) ||
7711 // -- For a non-type template-parameter of type pointer to
7712 // member function, no conversions apply. If the
7713 // template-argument represents a set of overloaded member
7714 // functions, the matching member function is selected from
7715 // the set (13.4).
7716 (ParamType->isMemberPointerType() &&
7717 ParamType->castAs<MemberPointerType>()->getPointeeType()
7718 ->isFunctionType())) {
7720 if (Arg->getType() == Context.OverloadTy) {
7721 if (FunctionDecl *Fn = ResolveAddressOfOverloadedFunction(Arg, ParamType,
7722 true,
7723 FoundResult)) {
7724 if (DiagnoseUseOfDecl(Fn, Arg->getBeginLoc()))
7725 return ExprError();
7727 ExprResult Res = FixOverloadedFunctionReference(Arg, FoundResult, Fn);
7728 if (Res.isInvalid())
7729 return ExprError();
7730 Arg = Res.get();
7731 ArgType = Arg->getType();
7732 } else
7733 return ExprError();
7736 if (!ParamType->isMemberPointerType()) {
7737 if (CheckTemplateArgumentAddressOfObjectOrFunction(
7738 *this, Param, ParamType, Arg, SugaredConverted,
7739 CanonicalConverted))
7740 return ExprError();
7741 return Arg;
7744 if (CheckTemplateArgumentPointerToMember(
7745 *this, Param, ParamType, Arg, SugaredConverted, CanonicalConverted))
7746 return ExprError();
7747 return Arg;
7750 if (ParamType->isPointerType()) {
7751 // -- for a non-type template-parameter of type pointer to
7752 // object, qualification conversions (4.4) and the
7753 // array-to-pointer conversion (4.2) are applied.
7754 // C++0x also allows a value of std::nullptr_t.
7755 assert(ParamType->getPointeeType()->isIncompleteOrObjectType() &&
7756 "Only object pointers allowed here");
7758 if (CheckTemplateArgumentAddressOfObjectOrFunction(
7759 *this, Param, ParamType, Arg, SugaredConverted, CanonicalConverted))
7760 return ExprError();
7761 return Arg;
7764 if (const ReferenceType *ParamRefType = ParamType->getAs<ReferenceType>()) {
7765 // -- For a non-type template-parameter of type reference to
7766 // object, no conversions apply. The type referred to by the
7767 // reference may be more cv-qualified than the (otherwise
7768 // identical) type of the template-argument. The
7769 // template-parameter is bound directly to the
7770 // template-argument, which must be an lvalue.
7771 assert(ParamRefType->getPointeeType()->isIncompleteOrObjectType() &&
7772 "Only object references allowed here");
7774 if (Arg->getType() == Context.OverloadTy) {
7775 if (FunctionDecl *Fn = ResolveAddressOfOverloadedFunction(Arg,
7776 ParamRefType->getPointeeType(),
7777 true,
7778 FoundResult)) {
7779 if (DiagnoseUseOfDecl(Fn, Arg->getBeginLoc()))
7780 return ExprError();
7781 ExprResult Res = FixOverloadedFunctionReference(Arg, FoundResult, Fn);
7782 if (Res.isInvalid())
7783 return ExprError();
7784 Arg = Res.get();
7785 ArgType = Arg->getType();
7786 } else
7787 return ExprError();
7790 if (CheckTemplateArgumentAddressOfObjectOrFunction(
7791 *this, Param, ParamType, Arg, SugaredConverted, CanonicalConverted))
7792 return ExprError();
7793 return Arg;
7796 // Deal with parameters of type std::nullptr_t.
7797 if (ParamType->isNullPtrType()) {
7798 if (Arg->isTypeDependent() || Arg->isValueDependent()) {
7799 SugaredConverted = TemplateArgument(Arg);
7800 CanonicalConverted =
7801 Context.getCanonicalTemplateArgument(SugaredConverted);
7802 return Arg;
7805 switch (isNullPointerValueTemplateArgument(*this, Param, ParamType, Arg)) {
7806 case NPV_NotNullPointer:
7807 Diag(Arg->getExprLoc(), diag::err_template_arg_not_convertible)
7808 << Arg->getType() << ParamType;
7809 NoteTemplateParameterLocation(*Param);
7810 return ExprError();
7812 case NPV_Error:
7813 return ExprError();
7815 case NPV_NullPointer:
7816 Diag(Arg->getExprLoc(), diag::warn_cxx98_compat_template_arg_null);
7817 SugaredConverted = TemplateArgument(ParamType,
7818 /*isNullPtr=*/true);
7819 CanonicalConverted = TemplateArgument(Context.getCanonicalType(ParamType),
7820 /*isNullPtr=*/true);
7821 return Arg;
7825 // -- For a non-type template-parameter of type pointer to data
7826 // member, qualification conversions (4.4) are applied.
7827 assert(ParamType->isMemberPointerType() && "Only pointers to members remain");
7829 if (CheckTemplateArgumentPointerToMember(
7830 *this, Param, ParamType, Arg, SugaredConverted, CanonicalConverted))
7831 return ExprError();
7832 return Arg;
7835 static void DiagnoseTemplateParameterListArityMismatch(
7836 Sema &S, TemplateParameterList *New, TemplateParameterList *Old,
7837 Sema::TemplateParameterListEqualKind Kind, SourceLocation TemplateArgLoc);
7839 /// Check a template argument against its corresponding
7840 /// template template parameter.
7842 /// This routine implements the semantics of C++ [temp.arg.template].
7843 /// It returns true if an error occurred, and false otherwise.
7844 bool Sema::CheckTemplateTemplateArgument(TemplateTemplateParmDecl *Param,
7845 TemplateParameterList *Params,
7846 TemplateArgumentLoc &Arg) {
7847 TemplateName Name = Arg.getArgument().getAsTemplateOrTemplatePattern();
7848 TemplateDecl *Template = Name.getAsTemplateDecl();
7849 if (!Template) {
7850 // Any dependent template name is fine.
7851 assert(Name.isDependent() && "Non-dependent template isn't a declaration?");
7852 return false;
7855 if (Template->isInvalidDecl())
7856 return true;
7858 // C++0x [temp.arg.template]p1:
7859 // A template-argument for a template template-parameter shall be
7860 // the name of a class template or an alias template, expressed as an
7861 // id-expression. When the template-argument names a class template, only
7862 // primary class templates are considered when matching the
7863 // template template argument with the corresponding parameter;
7864 // partial specializations are not considered even if their
7865 // parameter lists match that of the template template parameter.
7867 // Note that we also allow template template parameters here, which
7868 // will happen when we are dealing with, e.g., class template
7869 // partial specializations.
7870 if (!isa<ClassTemplateDecl>(Template) &&
7871 !isa<TemplateTemplateParmDecl>(Template) &&
7872 !isa<TypeAliasTemplateDecl>(Template) &&
7873 !isa<BuiltinTemplateDecl>(Template)) {
7874 assert(isa<FunctionTemplateDecl>(Template) &&
7875 "Only function templates are possible here");
7876 Diag(Arg.getLocation(), diag::err_template_arg_not_valid_template);
7877 Diag(Template->getLocation(), diag::note_template_arg_refers_here_func)
7878 << Template;
7881 // C++1z [temp.arg.template]p3: (DR 150)
7882 // A template-argument matches a template template-parameter P when P
7883 // is at least as specialized as the template-argument A.
7884 // FIXME: We should enable RelaxedTemplateTemplateArgs by default as it is a
7885 // defect report resolution from C++17 and shouldn't be introduced by
7886 // concepts.
7887 if (getLangOpts().RelaxedTemplateTemplateArgs) {
7888 // Quick check for the common case:
7889 // If P contains a parameter pack, then A [...] matches P if each of A's
7890 // template parameters matches the corresponding template parameter in
7891 // the template-parameter-list of P.
7892 if (TemplateParameterListsAreEqual(
7893 Template->getTemplateParameters(), Params, false,
7894 TPL_TemplateTemplateArgumentMatch, Arg.getLocation()) &&
7895 // If the argument has no associated constraints, then the parameter is
7896 // definitely at least as specialized as the argument.
7897 // Otherwise - we need a more thorough check.
7898 !Template->hasAssociatedConstraints())
7899 return false;
7901 if (isTemplateTemplateParameterAtLeastAsSpecializedAs(Params, Template,
7902 Arg.getLocation())) {
7903 // P2113
7904 // C++20[temp.func.order]p2
7905 // [...] If both deductions succeed, the partial ordering selects the
7906 // more constrained template (if one exists) as determined below.
7907 SmallVector<const Expr *, 3> ParamsAC, TemplateAC;
7908 Params->getAssociatedConstraints(ParamsAC);
7909 // C++2a[temp.arg.template]p3
7910 // [...] In this comparison, if P is unconstrained, the constraints on A
7911 // are not considered.
7912 if (ParamsAC.empty())
7913 return false;
7915 Template->getAssociatedConstraints(TemplateAC);
7917 bool IsParamAtLeastAsConstrained;
7918 if (IsAtLeastAsConstrained(Param, ParamsAC, Template, TemplateAC,
7919 IsParamAtLeastAsConstrained))
7920 return true;
7921 if (!IsParamAtLeastAsConstrained) {
7922 Diag(Arg.getLocation(),
7923 diag::err_template_template_parameter_not_at_least_as_constrained)
7924 << Template << Param << Arg.getSourceRange();
7925 Diag(Param->getLocation(), diag::note_entity_declared_at) << Param;
7926 Diag(Template->getLocation(), diag::note_entity_declared_at)
7927 << Template;
7928 MaybeEmitAmbiguousAtomicConstraintsDiagnostic(Param, ParamsAC, Template,
7929 TemplateAC);
7930 return true;
7932 return false;
7934 // FIXME: Produce better diagnostics for deduction failures.
7937 return !TemplateParameterListsAreEqual(Template->getTemplateParameters(),
7938 Params,
7939 true,
7940 TPL_TemplateTemplateArgumentMatch,
7941 Arg.getLocation());
7944 static Sema::SemaDiagnosticBuilder noteLocation(Sema &S, const NamedDecl &Decl,
7945 unsigned HereDiagID,
7946 unsigned ExternalDiagID) {
7947 if (Decl.getLocation().isValid())
7948 return S.Diag(Decl.getLocation(), HereDiagID);
7950 SmallString<128> Str;
7951 llvm::raw_svector_ostream Out(Str);
7952 PrintingPolicy PP = S.getPrintingPolicy();
7953 PP.TerseOutput = 1;
7954 Decl.print(Out, PP);
7955 return S.Diag(Decl.getLocation(), ExternalDiagID) << Out.str();
7958 void Sema::NoteTemplateLocation(const NamedDecl &Decl,
7959 std::optional<SourceRange> ParamRange) {
7960 SemaDiagnosticBuilder DB =
7961 noteLocation(*this, Decl, diag::note_template_decl_here,
7962 diag::note_template_decl_external);
7963 if (ParamRange && ParamRange->isValid()) {
7964 assert(Decl.getLocation().isValid() &&
7965 "Parameter range has location when Decl does not");
7966 DB << *ParamRange;
7970 void Sema::NoteTemplateParameterLocation(const NamedDecl &Decl) {
7971 noteLocation(*this, Decl, diag::note_template_param_here,
7972 diag::note_template_param_external);
7975 /// Given a non-type template argument that refers to a
7976 /// declaration and the type of its corresponding non-type template
7977 /// parameter, produce an expression that properly refers to that
7978 /// declaration.
7979 ExprResult
7980 Sema::BuildExpressionFromDeclTemplateArgument(const TemplateArgument &Arg,
7981 QualType ParamType,
7982 SourceLocation Loc) {
7983 // C++ [temp.param]p8:
7985 // A non-type template-parameter of type "array of T" or
7986 // "function returning T" is adjusted to be of type "pointer to
7987 // T" or "pointer to function returning T", respectively.
7988 if (ParamType->isArrayType())
7989 ParamType = Context.getArrayDecayedType(ParamType);
7990 else if (ParamType->isFunctionType())
7991 ParamType = Context.getPointerType(ParamType);
7993 // For a NULL non-type template argument, return nullptr casted to the
7994 // parameter's type.
7995 if (Arg.getKind() == TemplateArgument::NullPtr) {
7996 return ImpCastExprToType(
7997 new (Context) CXXNullPtrLiteralExpr(Context.NullPtrTy, Loc),
7998 ParamType,
7999 ParamType->getAs<MemberPointerType>()
8000 ? CK_NullToMemberPointer
8001 : CK_NullToPointer);
8003 assert(Arg.getKind() == TemplateArgument::Declaration &&
8004 "Only declaration template arguments permitted here");
8006 ValueDecl *VD = Arg.getAsDecl();
8008 CXXScopeSpec SS;
8009 if (ParamType->isMemberPointerType()) {
8010 // If this is a pointer to member, we need to use a qualified name to
8011 // form a suitable pointer-to-member constant.
8012 assert(VD->getDeclContext()->isRecord() &&
8013 (isa<CXXMethodDecl>(VD) || isa<FieldDecl>(VD) ||
8014 isa<IndirectFieldDecl>(VD)));
8015 QualType ClassType
8016 = Context.getTypeDeclType(cast<RecordDecl>(VD->getDeclContext()));
8017 NestedNameSpecifier *Qualifier
8018 = NestedNameSpecifier::Create(Context, nullptr, false,
8019 ClassType.getTypePtr());
8020 SS.MakeTrivial(Context, Qualifier, Loc);
8023 ExprResult RefExpr = BuildDeclarationNameExpr(
8024 SS, DeclarationNameInfo(VD->getDeclName(), Loc), VD);
8025 if (RefExpr.isInvalid())
8026 return ExprError();
8028 // For a pointer, the argument declaration is the pointee. Take its address.
8029 QualType ElemT(RefExpr.get()->getType()->getArrayElementTypeNoTypeQual(), 0);
8030 if (ParamType->isPointerType() && !ElemT.isNull() &&
8031 Context.hasSimilarType(ElemT, ParamType->getPointeeType())) {
8032 // Decay an array argument if we want a pointer to its first element.
8033 RefExpr = DefaultFunctionArrayConversion(RefExpr.get());
8034 if (RefExpr.isInvalid())
8035 return ExprError();
8036 } else if (ParamType->isPointerType() || ParamType->isMemberPointerType()) {
8037 // For any other pointer, take the address (or form a pointer-to-member).
8038 RefExpr = CreateBuiltinUnaryOp(Loc, UO_AddrOf, RefExpr.get());
8039 if (RefExpr.isInvalid())
8040 return ExprError();
8041 } else if (ParamType->isRecordType()) {
8042 assert(isa<TemplateParamObjectDecl>(VD) &&
8043 "arg for class template param not a template parameter object");
8044 // No conversions apply in this case.
8045 return RefExpr;
8046 } else {
8047 assert(ParamType->isReferenceType() &&
8048 "unexpected type for decl template argument");
8051 // At this point we should have the right value category.
8052 assert(ParamType->isReferenceType() == RefExpr.get()->isLValue() &&
8053 "value kind mismatch for non-type template argument");
8055 // The type of the template parameter can differ from the type of the
8056 // argument in various ways; convert it now if necessary.
8057 QualType DestExprType = ParamType.getNonLValueExprType(Context);
8058 if (!Context.hasSameType(RefExpr.get()->getType(), DestExprType)) {
8059 CastKind CK;
8060 QualType Ignored;
8061 if (Context.hasSimilarType(RefExpr.get()->getType(), DestExprType) ||
8062 IsFunctionConversion(RefExpr.get()->getType(), DestExprType, Ignored)) {
8063 CK = CK_NoOp;
8064 } else if (ParamType->isVoidPointerType() &&
8065 RefExpr.get()->getType()->isPointerType()) {
8066 CK = CK_BitCast;
8067 } else {
8068 // FIXME: Pointers to members can need conversion derived-to-base or
8069 // base-to-derived conversions. We currently don't retain enough
8070 // information to convert properly (we need to track a cast path or
8071 // subobject number in the template argument).
8072 llvm_unreachable(
8073 "unexpected conversion required for non-type template argument");
8075 RefExpr = ImpCastExprToType(RefExpr.get(), DestExprType, CK,
8076 RefExpr.get()->getValueKind());
8079 return RefExpr;
8082 /// Construct a new expression that refers to the given
8083 /// integral template argument with the given source-location
8084 /// information.
8086 /// This routine takes care of the mapping from an integral template
8087 /// argument (which may have any integral type) to the appropriate
8088 /// literal value.
8089 ExprResult
8090 Sema::BuildExpressionFromIntegralTemplateArgument(const TemplateArgument &Arg,
8091 SourceLocation Loc) {
8092 assert(Arg.getKind() == TemplateArgument::Integral &&
8093 "Operation is only valid for integral template arguments");
8094 QualType OrigT = Arg.getIntegralType();
8096 // If this is an enum type that we're instantiating, we need to use an integer
8097 // type the same size as the enumerator. We don't want to build an
8098 // IntegerLiteral with enum type. The integer type of an enum type can be of
8099 // any integral type with C++11 enum classes, make sure we create the right
8100 // type of literal for it.
8101 QualType T = OrigT;
8102 if (const EnumType *ET = OrigT->getAs<EnumType>())
8103 T = ET->getDecl()->getIntegerType();
8105 Expr *E;
8106 if (T->isAnyCharacterType()) {
8107 CharacterLiteralKind Kind;
8108 if (T->isWideCharType())
8109 Kind = CharacterLiteralKind::Wide;
8110 else if (T->isChar8Type() && getLangOpts().Char8)
8111 Kind = CharacterLiteralKind::UTF8;
8112 else if (T->isChar16Type())
8113 Kind = CharacterLiteralKind::UTF16;
8114 else if (T->isChar32Type())
8115 Kind = CharacterLiteralKind::UTF32;
8116 else
8117 Kind = CharacterLiteralKind::Ascii;
8119 E = new (Context) CharacterLiteral(Arg.getAsIntegral().getZExtValue(),
8120 Kind, T, Loc);
8121 } else if (T->isBooleanType()) {
8122 E = CXXBoolLiteralExpr::Create(Context, Arg.getAsIntegral().getBoolValue(),
8123 T, Loc);
8124 } else if (T->isNullPtrType()) {
8125 E = new (Context) CXXNullPtrLiteralExpr(Context.NullPtrTy, Loc);
8126 } else {
8127 E = IntegerLiteral::Create(Context, Arg.getAsIntegral(), T, Loc);
8130 if (OrigT->isEnumeralType()) {
8131 // FIXME: This is a hack. We need a better way to handle substituted
8132 // non-type template parameters.
8133 E = CStyleCastExpr::Create(Context, OrigT, VK_PRValue, CK_IntegralCast, E,
8134 nullptr, CurFPFeatureOverrides(),
8135 Context.getTrivialTypeSourceInfo(OrigT, Loc),
8136 Loc, Loc);
8139 return E;
8142 /// Match two template parameters within template parameter lists.
8143 static bool MatchTemplateParameterKind(
8144 Sema &S, NamedDecl *New,
8145 const Sema::TemplateCompareNewDeclInfo &NewInstFrom, NamedDecl *Old,
8146 const NamedDecl *OldInstFrom, bool Complain,
8147 Sema::TemplateParameterListEqualKind Kind, SourceLocation TemplateArgLoc) {
8148 // Check the actual kind (type, non-type, template).
8149 if (Old->getKind() != New->getKind()) {
8150 if (Complain) {
8151 unsigned NextDiag = diag::err_template_param_different_kind;
8152 if (TemplateArgLoc.isValid()) {
8153 S.Diag(TemplateArgLoc, diag::err_template_arg_template_params_mismatch);
8154 NextDiag = diag::note_template_param_different_kind;
8156 S.Diag(New->getLocation(), NextDiag)
8157 << (Kind != Sema::TPL_TemplateMatch);
8158 S.Diag(Old->getLocation(), diag::note_template_prev_declaration)
8159 << (Kind != Sema::TPL_TemplateMatch);
8162 return false;
8165 // Check that both are parameter packs or neither are parameter packs.
8166 // However, if we are matching a template template argument to a
8167 // template template parameter, the template template parameter can have
8168 // a parameter pack where the template template argument does not.
8169 if (Old->isTemplateParameterPack() != New->isTemplateParameterPack() &&
8170 !(Kind == Sema::TPL_TemplateTemplateArgumentMatch &&
8171 Old->isTemplateParameterPack())) {
8172 if (Complain) {
8173 unsigned NextDiag = diag::err_template_parameter_pack_non_pack;
8174 if (TemplateArgLoc.isValid()) {
8175 S.Diag(TemplateArgLoc,
8176 diag::err_template_arg_template_params_mismatch);
8177 NextDiag = diag::note_template_parameter_pack_non_pack;
8180 unsigned ParamKind = isa<TemplateTypeParmDecl>(New)? 0
8181 : isa<NonTypeTemplateParmDecl>(New)? 1
8182 : 2;
8183 S.Diag(New->getLocation(), NextDiag)
8184 << ParamKind << New->isParameterPack();
8185 S.Diag(Old->getLocation(), diag::note_template_parameter_pack_here)
8186 << ParamKind << Old->isParameterPack();
8189 return false;
8192 // For non-type template parameters, check the type of the parameter.
8193 if (NonTypeTemplateParmDecl *OldNTTP
8194 = dyn_cast<NonTypeTemplateParmDecl>(Old)) {
8195 NonTypeTemplateParmDecl *NewNTTP = cast<NonTypeTemplateParmDecl>(New);
8197 // If we are matching a template template argument to a template
8198 // template parameter and one of the non-type template parameter types
8199 // is dependent, then we must wait until template instantiation time
8200 // to actually compare the arguments.
8201 if (Kind != Sema::TPL_TemplateTemplateArgumentMatch ||
8202 (!OldNTTP->getType()->isDependentType() &&
8203 !NewNTTP->getType()->isDependentType())) {
8204 // C++20 [temp.over.link]p6:
8205 // Two [non-type] template-parameters are equivalent [if] they have
8206 // equivalent types ignoring the use of type-constraints for
8207 // placeholder types
8208 QualType OldType = S.Context.getUnconstrainedType(OldNTTP->getType());
8209 QualType NewType = S.Context.getUnconstrainedType(NewNTTP->getType());
8210 if (!S.Context.hasSameType(OldType, NewType)) {
8211 if (Complain) {
8212 unsigned NextDiag = diag::err_template_nontype_parm_different_type;
8213 if (TemplateArgLoc.isValid()) {
8214 S.Diag(TemplateArgLoc,
8215 diag::err_template_arg_template_params_mismatch);
8216 NextDiag = diag::note_template_nontype_parm_different_type;
8218 S.Diag(NewNTTP->getLocation(), NextDiag)
8219 << NewNTTP->getType()
8220 << (Kind != Sema::TPL_TemplateMatch);
8221 S.Diag(OldNTTP->getLocation(),
8222 diag::note_template_nontype_parm_prev_declaration)
8223 << OldNTTP->getType();
8226 return false;
8230 // For template template parameters, check the template parameter types.
8231 // The template parameter lists of template template
8232 // parameters must agree.
8233 else if (TemplateTemplateParmDecl *OldTTP =
8234 dyn_cast<TemplateTemplateParmDecl>(Old)) {
8235 TemplateTemplateParmDecl *NewTTP = cast<TemplateTemplateParmDecl>(New);
8236 if (!S.TemplateParameterListsAreEqual(
8237 NewInstFrom, NewTTP->getTemplateParameters(), OldInstFrom,
8238 OldTTP->getTemplateParameters(), Complain,
8239 (Kind == Sema::TPL_TemplateMatch
8240 ? Sema::TPL_TemplateTemplateParmMatch
8241 : Kind),
8242 TemplateArgLoc))
8243 return false;
8246 if (Kind != Sema::TPL_TemplateParamsEquivalent &&
8247 Kind != Sema::TPL_TemplateTemplateArgumentMatch &&
8248 !isa<TemplateTemplateParmDecl>(Old)) {
8249 const Expr *NewC = nullptr, *OldC = nullptr;
8251 if (isa<TemplateTypeParmDecl>(New)) {
8252 if (const auto *TC = cast<TemplateTypeParmDecl>(New)->getTypeConstraint())
8253 NewC = TC->getImmediatelyDeclaredConstraint();
8254 if (const auto *TC = cast<TemplateTypeParmDecl>(Old)->getTypeConstraint())
8255 OldC = TC->getImmediatelyDeclaredConstraint();
8256 } else if (isa<NonTypeTemplateParmDecl>(New)) {
8257 if (const Expr *E = cast<NonTypeTemplateParmDecl>(New)
8258 ->getPlaceholderTypeConstraint())
8259 NewC = E;
8260 if (const Expr *E = cast<NonTypeTemplateParmDecl>(Old)
8261 ->getPlaceholderTypeConstraint())
8262 OldC = E;
8263 } else
8264 llvm_unreachable("unexpected template parameter type");
8266 auto Diagnose = [&] {
8267 S.Diag(NewC ? NewC->getBeginLoc() : New->getBeginLoc(),
8268 diag::err_template_different_type_constraint);
8269 S.Diag(OldC ? OldC->getBeginLoc() : Old->getBeginLoc(),
8270 diag::note_template_prev_declaration) << /*declaration*/0;
8273 if (!NewC != !OldC) {
8274 if (Complain)
8275 Diagnose();
8276 return false;
8279 if (NewC) {
8280 if (!S.AreConstraintExpressionsEqual(OldInstFrom, OldC, NewInstFrom,
8281 NewC)) {
8282 if (Complain)
8283 Diagnose();
8284 return false;
8289 return true;
8292 /// Diagnose a known arity mismatch when comparing template argument
8293 /// lists.
8294 static
8295 void DiagnoseTemplateParameterListArityMismatch(Sema &S,
8296 TemplateParameterList *New,
8297 TemplateParameterList *Old,
8298 Sema::TemplateParameterListEqualKind Kind,
8299 SourceLocation TemplateArgLoc) {
8300 unsigned NextDiag = diag::err_template_param_list_different_arity;
8301 if (TemplateArgLoc.isValid()) {
8302 S.Diag(TemplateArgLoc, diag::err_template_arg_template_params_mismatch);
8303 NextDiag = diag::note_template_param_list_different_arity;
8305 S.Diag(New->getTemplateLoc(), NextDiag)
8306 << (New->size() > Old->size())
8307 << (Kind != Sema::TPL_TemplateMatch)
8308 << SourceRange(New->getTemplateLoc(), New->getRAngleLoc());
8309 S.Diag(Old->getTemplateLoc(), diag::note_template_prev_declaration)
8310 << (Kind != Sema::TPL_TemplateMatch)
8311 << SourceRange(Old->getTemplateLoc(), Old->getRAngleLoc());
8314 /// Determine whether the given template parameter lists are
8315 /// equivalent.
8317 /// \param New The new template parameter list, typically written in the
8318 /// source code as part of a new template declaration.
8320 /// \param Old The old template parameter list, typically found via
8321 /// name lookup of the template declared with this template parameter
8322 /// list.
8324 /// \param Complain If true, this routine will produce a diagnostic if
8325 /// the template parameter lists are not equivalent.
8327 /// \param Kind describes how we are to match the template parameter lists.
8329 /// \param TemplateArgLoc If this source location is valid, then we
8330 /// are actually checking the template parameter list of a template
8331 /// argument (New) against the template parameter list of its
8332 /// corresponding template template parameter (Old). We produce
8333 /// slightly different diagnostics in this scenario.
8335 /// \returns True if the template parameter lists are equal, false
8336 /// otherwise.
8337 bool Sema::TemplateParameterListsAreEqual(
8338 const TemplateCompareNewDeclInfo &NewInstFrom, TemplateParameterList *New,
8339 const NamedDecl *OldInstFrom, TemplateParameterList *Old, bool Complain,
8340 TemplateParameterListEqualKind Kind, SourceLocation TemplateArgLoc) {
8341 if (Old->size() != New->size() && Kind != TPL_TemplateTemplateArgumentMatch) {
8342 if (Complain)
8343 DiagnoseTemplateParameterListArityMismatch(*this, New, Old, Kind,
8344 TemplateArgLoc);
8346 return false;
8349 // C++0x [temp.arg.template]p3:
8350 // A template-argument matches a template template-parameter (call it P)
8351 // when each of the template parameters in the template-parameter-list of
8352 // the template-argument's corresponding class template or alias template
8353 // (call it A) matches the corresponding template parameter in the
8354 // template-parameter-list of P. [...]
8355 TemplateParameterList::iterator NewParm = New->begin();
8356 TemplateParameterList::iterator NewParmEnd = New->end();
8357 for (TemplateParameterList::iterator OldParm = Old->begin(),
8358 OldParmEnd = Old->end();
8359 OldParm != OldParmEnd; ++OldParm) {
8360 if (Kind != TPL_TemplateTemplateArgumentMatch ||
8361 !(*OldParm)->isTemplateParameterPack()) {
8362 if (NewParm == NewParmEnd) {
8363 if (Complain)
8364 DiagnoseTemplateParameterListArityMismatch(*this, New, Old, Kind,
8365 TemplateArgLoc);
8367 return false;
8370 if (!MatchTemplateParameterKind(*this, *NewParm, NewInstFrom, *OldParm,
8371 OldInstFrom, Complain, Kind,
8372 TemplateArgLoc))
8373 return false;
8375 ++NewParm;
8376 continue;
8379 // C++0x [temp.arg.template]p3:
8380 // [...] When P's template- parameter-list contains a template parameter
8381 // pack (14.5.3), the template parameter pack will match zero or more
8382 // template parameters or template parameter packs in the
8383 // template-parameter-list of A with the same type and form as the
8384 // template parameter pack in P (ignoring whether those template
8385 // parameters are template parameter packs).
8386 for (; NewParm != NewParmEnd; ++NewParm) {
8387 if (!MatchTemplateParameterKind(*this, *NewParm, NewInstFrom, *OldParm,
8388 OldInstFrom, Complain, Kind,
8389 TemplateArgLoc))
8390 return false;
8394 // Make sure we exhausted all of the arguments.
8395 if (NewParm != NewParmEnd) {
8396 if (Complain)
8397 DiagnoseTemplateParameterListArityMismatch(*this, New, Old, Kind,
8398 TemplateArgLoc);
8400 return false;
8403 if (Kind != TPL_TemplateTemplateArgumentMatch &&
8404 Kind != TPL_TemplateParamsEquivalent) {
8405 const Expr *NewRC = New->getRequiresClause();
8406 const Expr *OldRC = Old->getRequiresClause();
8408 auto Diagnose = [&] {
8409 Diag(NewRC ? NewRC->getBeginLoc() : New->getTemplateLoc(),
8410 diag::err_template_different_requires_clause);
8411 Diag(OldRC ? OldRC->getBeginLoc() : Old->getTemplateLoc(),
8412 diag::note_template_prev_declaration) << /*declaration*/0;
8415 if (!NewRC != !OldRC) {
8416 if (Complain)
8417 Diagnose();
8418 return false;
8421 if (NewRC) {
8422 if (!AreConstraintExpressionsEqual(OldInstFrom, OldRC, NewInstFrom,
8423 NewRC)) {
8424 if (Complain)
8425 Diagnose();
8426 return false;
8431 return true;
8434 /// Check whether a template can be declared within this scope.
8436 /// If the template declaration is valid in this scope, returns
8437 /// false. Otherwise, issues a diagnostic and returns true.
8438 bool
8439 Sema::CheckTemplateDeclScope(Scope *S, TemplateParameterList *TemplateParams) {
8440 if (!S)
8441 return false;
8443 // Find the nearest enclosing declaration scope.
8444 while ((S->getFlags() & Scope::DeclScope) == 0 ||
8445 (S->getFlags() & Scope::TemplateParamScope) != 0)
8446 S = S->getParent();
8448 // C++ [temp.pre]p6: [P2096]
8449 // A template, explicit specialization, or partial specialization shall not
8450 // have C linkage.
8451 DeclContext *Ctx = S->getEntity();
8452 if (Ctx && Ctx->isExternCContext()) {
8453 Diag(TemplateParams->getTemplateLoc(), diag::err_template_linkage)
8454 << TemplateParams->getSourceRange();
8455 if (const LinkageSpecDecl *LSD = Ctx->getExternCContext())
8456 Diag(LSD->getExternLoc(), diag::note_extern_c_begins_here);
8457 return true;
8459 Ctx = Ctx ? Ctx->getRedeclContext() : nullptr;
8461 // C++ [temp]p2:
8462 // A template-declaration can appear only as a namespace scope or
8463 // class scope declaration.
8464 // C++ [temp.expl.spec]p3:
8465 // An explicit specialization may be declared in any scope in which the
8466 // corresponding primary template may be defined.
8467 // C++ [temp.class.spec]p6: [P2096]
8468 // A partial specialization may be declared in any scope in which the
8469 // corresponding primary template may be defined.
8470 if (Ctx) {
8471 if (Ctx->isFileContext())
8472 return false;
8473 if (CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(Ctx)) {
8474 // C++ [temp.mem]p2:
8475 // A local class shall not have member templates.
8476 if (RD->isLocalClass())
8477 return Diag(TemplateParams->getTemplateLoc(),
8478 diag::err_template_inside_local_class)
8479 << TemplateParams->getSourceRange();
8480 else
8481 return false;
8485 return Diag(TemplateParams->getTemplateLoc(),
8486 diag::err_template_outside_namespace_or_class_scope)
8487 << TemplateParams->getSourceRange();
8490 /// Determine what kind of template specialization the given declaration
8491 /// is.
8492 static TemplateSpecializationKind getTemplateSpecializationKind(Decl *D) {
8493 if (!D)
8494 return TSK_Undeclared;
8496 if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(D))
8497 return Record->getTemplateSpecializationKind();
8498 if (FunctionDecl *Function = dyn_cast<FunctionDecl>(D))
8499 return Function->getTemplateSpecializationKind();
8500 if (VarDecl *Var = dyn_cast<VarDecl>(D))
8501 return Var->getTemplateSpecializationKind();
8503 return TSK_Undeclared;
8506 /// Check whether a specialization is well-formed in the current
8507 /// context.
8509 /// This routine determines whether a template specialization can be declared
8510 /// in the current context (C++ [temp.expl.spec]p2).
8512 /// \param S the semantic analysis object for which this check is being
8513 /// performed.
8515 /// \param Specialized the entity being specialized or instantiated, which
8516 /// may be a kind of template (class template, function template, etc.) or
8517 /// a member of a class template (member function, static data member,
8518 /// member class).
8520 /// \param PrevDecl the previous declaration of this entity, if any.
8522 /// \param Loc the location of the explicit specialization or instantiation of
8523 /// this entity.
8525 /// \param IsPartialSpecialization whether this is a partial specialization of
8526 /// a class template.
8528 /// \returns true if there was an error that we cannot recover from, false
8529 /// otherwise.
8530 static bool CheckTemplateSpecializationScope(Sema &S,
8531 NamedDecl *Specialized,
8532 NamedDecl *PrevDecl,
8533 SourceLocation Loc,
8534 bool IsPartialSpecialization) {
8535 // Keep these "kind" numbers in sync with the %select statements in the
8536 // various diagnostics emitted by this routine.
8537 int EntityKind = 0;
8538 if (isa<ClassTemplateDecl>(Specialized))
8539 EntityKind = IsPartialSpecialization? 1 : 0;
8540 else if (isa<VarTemplateDecl>(Specialized))
8541 EntityKind = IsPartialSpecialization ? 3 : 2;
8542 else if (isa<FunctionTemplateDecl>(Specialized))
8543 EntityKind = 4;
8544 else if (isa<CXXMethodDecl>(Specialized))
8545 EntityKind = 5;
8546 else if (isa<VarDecl>(Specialized))
8547 EntityKind = 6;
8548 else if (isa<RecordDecl>(Specialized))
8549 EntityKind = 7;
8550 else if (isa<EnumDecl>(Specialized) && S.getLangOpts().CPlusPlus11)
8551 EntityKind = 8;
8552 else {
8553 S.Diag(Loc, diag::err_template_spec_unknown_kind)
8554 << S.getLangOpts().CPlusPlus11;
8555 S.Diag(Specialized->getLocation(), diag::note_specialized_entity);
8556 return true;
8559 // C++ [temp.expl.spec]p2:
8560 // An explicit specialization may be declared in any scope in which
8561 // the corresponding primary template may be defined.
8562 if (S.CurContext->getRedeclContext()->isFunctionOrMethod()) {
8563 S.Diag(Loc, diag::err_template_spec_decl_function_scope)
8564 << Specialized;
8565 return true;
8568 // C++ [temp.class.spec]p6:
8569 // A class template partial specialization may be declared in any
8570 // scope in which the primary template may be defined.
8571 DeclContext *SpecializedContext =
8572 Specialized->getDeclContext()->getRedeclContext();
8573 DeclContext *DC = S.CurContext->getRedeclContext();
8575 // Make sure that this redeclaration (or definition) occurs in the same
8576 // scope or an enclosing namespace.
8577 if (!(DC->isFileContext() ? DC->Encloses(SpecializedContext)
8578 : DC->Equals(SpecializedContext))) {
8579 if (isa<TranslationUnitDecl>(SpecializedContext))
8580 S.Diag(Loc, diag::err_template_spec_redecl_global_scope)
8581 << EntityKind << Specialized;
8582 else {
8583 auto *ND = cast<NamedDecl>(SpecializedContext);
8584 int Diag = diag::err_template_spec_redecl_out_of_scope;
8585 if (S.getLangOpts().MicrosoftExt && !DC->isRecord())
8586 Diag = diag::ext_ms_template_spec_redecl_out_of_scope;
8587 S.Diag(Loc, Diag) << EntityKind << Specialized
8588 << ND << isa<CXXRecordDecl>(ND);
8591 S.Diag(Specialized->getLocation(), diag::note_specialized_entity);
8593 // Don't allow specializing in the wrong class during error recovery.
8594 // Otherwise, things can go horribly wrong.
8595 if (DC->isRecord())
8596 return true;
8599 return false;
8602 static SourceRange findTemplateParameterInType(unsigned Depth, Expr *E) {
8603 if (!E->isTypeDependent())
8604 return SourceLocation();
8605 DependencyChecker Checker(Depth, /*IgnoreNonTypeDependent*/true);
8606 Checker.TraverseStmt(E);
8607 if (Checker.MatchLoc.isInvalid())
8608 return E->getSourceRange();
8609 return Checker.MatchLoc;
8612 static SourceRange findTemplateParameter(unsigned Depth, TypeLoc TL) {
8613 if (!TL.getType()->isDependentType())
8614 return SourceLocation();
8615 DependencyChecker Checker(Depth, /*IgnoreNonTypeDependent*/true);
8616 Checker.TraverseTypeLoc(TL);
8617 if (Checker.MatchLoc.isInvalid())
8618 return TL.getSourceRange();
8619 return Checker.MatchLoc;
8622 /// Subroutine of Sema::CheckTemplatePartialSpecializationArgs
8623 /// that checks non-type template partial specialization arguments.
8624 static bool CheckNonTypeTemplatePartialSpecializationArgs(
8625 Sema &S, SourceLocation TemplateNameLoc, NonTypeTemplateParmDecl *Param,
8626 const TemplateArgument *Args, unsigned NumArgs, bool IsDefaultArgument) {
8627 for (unsigned I = 0; I != NumArgs; ++I) {
8628 if (Args[I].getKind() == TemplateArgument::Pack) {
8629 if (CheckNonTypeTemplatePartialSpecializationArgs(
8630 S, TemplateNameLoc, Param, Args[I].pack_begin(),
8631 Args[I].pack_size(), IsDefaultArgument))
8632 return true;
8634 continue;
8637 if (Args[I].getKind() != TemplateArgument::Expression)
8638 continue;
8640 Expr *ArgExpr = Args[I].getAsExpr();
8642 // We can have a pack expansion of any of the bullets below.
8643 if (PackExpansionExpr *Expansion = dyn_cast<PackExpansionExpr>(ArgExpr))
8644 ArgExpr = Expansion->getPattern();
8646 // Strip off any implicit casts we added as part of type checking.
8647 while (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(ArgExpr))
8648 ArgExpr = ICE->getSubExpr();
8650 // C++ [temp.class.spec]p8:
8651 // A non-type argument is non-specialized if it is the name of a
8652 // non-type parameter. All other non-type arguments are
8653 // specialized.
8655 // Below, we check the two conditions that only apply to
8656 // specialized non-type arguments, so skip any non-specialized
8657 // arguments.
8658 if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(ArgExpr))
8659 if (isa<NonTypeTemplateParmDecl>(DRE->getDecl()))
8660 continue;
8662 // C++ [temp.class.spec]p9:
8663 // Within the argument list of a class template partial
8664 // specialization, the following restrictions apply:
8665 // -- A partially specialized non-type argument expression
8666 // shall not involve a template parameter of the partial
8667 // specialization except when the argument expression is a
8668 // simple identifier.
8669 // -- The type of a template parameter corresponding to a
8670 // specialized non-type argument shall not be dependent on a
8671 // parameter of the specialization.
8672 // DR1315 removes the first bullet, leaving an incoherent set of rules.
8673 // We implement a compromise between the original rules and DR1315:
8674 // -- A specialized non-type template argument shall not be
8675 // type-dependent and the corresponding template parameter
8676 // shall have a non-dependent type.
8677 SourceRange ParamUseRange =
8678 findTemplateParameterInType(Param->getDepth(), ArgExpr);
8679 if (ParamUseRange.isValid()) {
8680 if (IsDefaultArgument) {
8681 S.Diag(TemplateNameLoc,
8682 diag::err_dependent_non_type_arg_in_partial_spec);
8683 S.Diag(ParamUseRange.getBegin(),
8684 diag::note_dependent_non_type_default_arg_in_partial_spec)
8685 << ParamUseRange;
8686 } else {
8687 S.Diag(ParamUseRange.getBegin(),
8688 diag::err_dependent_non_type_arg_in_partial_spec)
8689 << ParamUseRange;
8691 return true;
8694 ParamUseRange = findTemplateParameter(
8695 Param->getDepth(), Param->getTypeSourceInfo()->getTypeLoc());
8696 if (ParamUseRange.isValid()) {
8697 S.Diag(IsDefaultArgument ? TemplateNameLoc : ArgExpr->getBeginLoc(),
8698 diag::err_dependent_typed_non_type_arg_in_partial_spec)
8699 << Param->getType();
8700 S.NoteTemplateParameterLocation(*Param);
8701 return true;
8705 return false;
8708 /// Check the non-type template arguments of a class template
8709 /// partial specialization according to C++ [temp.class.spec]p9.
8711 /// \param TemplateNameLoc the location of the template name.
8712 /// \param PrimaryTemplate the template parameters of the primary class
8713 /// template.
8714 /// \param NumExplicit the number of explicitly-specified template arguments.
8715 /// \param TemplateArgs the template arguments of the class template
8716 /// partial specialization.
8718 /// \returns \c true if there was an error, \c false otherwise.
8719 bool Sema::CheckTemplatePartialSpecializationArgs(
8720 SourceLocation TemplateNameLoc, TemplateDecl *PrimaryTemplate,
8721 unsigned NumExplicit, ArrayRef<TemplateArgument> TemplateArgs) {
8722 // We have to be conservative when checking a template in a dependent
8723 // context.
8724 if (PrimaryTemplate->getDeclContext()->isDependentContext())
8725 return false;
8727 TemplateParameterList *TemplateParams =
8728 PrimaryTemplate->getTemplateParameters();
8729 for (unsigned I = 0, N = TemplateParams->size(); I != N; ++I) {
8730 NonTypeTemplateParmDecl *Param
8731 = dyn_cast<NonTypeTemplateParmDecl>(TemplateParams->getParam(I));
8732 if (!Param)
8733 continue;
8735 if (CheckNonTypeTemplatePartialSpecializationArgs(*this, TemplateNameLoc,
8736 Param, &TemplateArgs[I],
8737 1, I >= NumExplicit))
8738 return true;
8741 return false;
8744 DeclResult Sema::ActOnClassTemplateSpecialization(
8745 Scope *S, unsigned TagSpec, TagUseKind TUK, SourceLocation KWLoc,
8746 SourceLocation ModulePrivateLoc, CXXScopeSpec &SS,
8747 TemplateIdAnnotation &TemplateId, const ParsedAttributesView &Attr,
8748 MultiTemplateParamsArg TemplateParameterLists, SkipBodyInfo *SkipBody) {
8749 assert(TUK != TUK_Reference && "References are not specializations");
8751 // NOTE: KWLoc is the location of the tag keyword. This will instead
8752 // store the location of the outermost template keyword in the declaration.
8753 SourceLocation TemplateKWLoc = TemplateParameterLists.size() > 0
8754 ? TemplateParameterLists[0]->getTemplateLoc() : KWLoc;
8755 SourceLocation TemplateNameLoc = TemplateId.TemplateNameLoc;
8756 SourceLocation LAngleLoc = TemplateId.LAngleLoc;
8757 SourceLocation RAngleLoc = TemplateId.RAngleLoc;
8759 // Find the class template we're specializing
8760 TemplateName Name = TemplateId.Template.get();
8761 ClassTemplateDecl *ClassTemplate
8762 = dyn_cast_or_null<ClassTemplateDecl>(Name.getAsTemplateDecl());
8764 if (!ClassTemplate) {
8765 Diag(TemplateNameLoc, diag::err_not_class_template_specialization)
8766 << (Name.getAsTemplateDecl() &&
8767 isa<TemplateTemplateParmDecl>(Name.getAsTemplateDecl()));
8768 return true;
8771 bool isMemberSpecialization = false;
8772 bool isPartialSpecialization = false;
8774 // Check the validity of the template headers that introduce this
8775 // template.
8776 // FIXME: We probably shouldn't complain about these headers for
8777 // friend declarations.
8778 bool Invalid = false;
8779 TemplateParameterList *TemplateParams =
8780 MatchTemplateParametersToScopeSpecifier(
8781 KWLoc, TemplateNameLoc, SS, &TemplateId,
8782 TemplateParameterLists, TUK == TUK_Friend, isMemberSpecialization,
8783 Invalid);
8784 if (Invalid)
8785 return true;
8787 // Check that we can declare a template specialization here.
8788 if (TemplateParams && CheckTemplateDeclScope(S, TemplateParams))
8789 return true;
8791 if (TemplateParams && TemplateParams->size() > 0) {
8792 isPartialSpecialization = true;
8794 if (TUK == TUK_Friend) {
8795 Diag(KWLoc, diag::err_partial_specialization_friend)
8796 << SourceRange(LAngleLoc, RAngleLoc);
8797 return true;
8800 // C++ [temp.class.spec]p10:
8801 // The template parameter list of a specialization shall not
8802 // contain default template argument values.
8803 for (unsigned I = 0, N = TemplateParams->size(); I != N; ++I) {
8804 Decl *Param = TemplateParams->getParam(I);
8805 if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(Param)) {
8806 if (TTP->hasDefaultArgument()) {
8807 Diag(TTP->getDefaultArgumentLoc(),
8808 diag::err_default_arg_in_partial_spec);
8809 TTP->removeDefaultArgument();
8811 } else if (NonTypeTemplateParmDecl *NTTP
8812 = dyn_cast<NonTypeTemplateParmDecl>(Param)) {
8813 if (Expr *DefArg = NTTP->getDefaultArgument()) {
8814 Diag(NTTP->getDefaultArgumentLoc(),
8815 diag::err_default_arg_in_partial_spec)
8816 << DefArg->getSourceRange();
8817 NTTP->removeDefaultArgument();
8819 } else {
8820 TemplateTemplateParmDecl *TTP = cast<TemplateTemplateParmDecl>(Param);
8821 if (TTP->hasDefaultArgument()) {
8822 Diag(TTP->getDefaultArgument().getLocation(),
8823 diag::err_default_arg_in_partial_spec)
8824 << TTP->getDefaultArgument().getSourceRange();
8825 TTP->removeDefaultArgument();
8829 } else if (TemplateParams) {
8830 if (TUK == TUK_Friend)
8831 Diag(KWLoc, diag::err_template_spec_friend)
8832 << FixItHint::CreateRemoval(
8833 SourceRange(TemplateParams->getTemplateLoc(),
8834 TemplateParams->getRAngleLoc()))
8835 << SourceRange(LAngleLoc, RAngleLoc);
8836 } else {
8837 assert(TUK == TUK_Friend && "should have a 'template<>' for this decl");
8840 // Check that the specialization uses the same tag kind as the
8841 // original template.
8842 TagTypeKind Kind = TypeWithKeyword::getTagTypeKindForTypeSpec(TagSpec);
8843 assert(Kind != TagTypeKind::Enum &&
8844 "Invalid enum tag in class template spec!");
8845 if (!isAcceptableTagRedeclaration(ClassTemplate->getTemplatedDecl(),
8846 Kind, TUK == TUK_Definition, KWLoc,
8847 ClassTemplate->getIdentifier())) {
8848 Diag(KWLoc, diag::err_use_with_wrong_tag)
8849 << ClassTemplate
8850 << FixItHint::CreateReplacement(KWLoc,
8851 ClassTemplate->getTemplatedDecl()->getKindName());
8852 Diag(ClassTemplate->getTemplatedDecl()->getLocation(),
8853 diag::note_previous_use);
8854 Kind = ClassTemplate->getTemplatedDecl()->getTagKind();
8857 // Translate the parser's template argument list in our AST format.
8858 TemplateArgumentListInfo TemplateArgs =
8859 makeTemplateArgumentListInfo(*this, TemplateId);
8861 // Check for unexpanded parameter packs in any of the template arguments.
8862 for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I)
8863 if (DiagnoseUnexpandedParameterPack(TemplateArgs[I],
8864 isPartialSpecialization
8865 ? UPPC_PartialSpecialization
8866 : UPPC_ExplicitSpecialization))
8867 return true;
8869 // Check that the template argument list is well-formed for this
8870 // template.
8871 SmallVector<TemplateArgument, 4> SugaredConverted, CanonicalConverted;
8872 if (CheckTemplateArgumentList(ClassTemplate, TemplateNameLoc, TemplateArgs,
8873 false, SugaredConverted, CanonicalConverted,
8874 /*UpdateArgsWithConversions=*/true))
8875 return true;
8877 // Find the class template (partial) specialization declaration that
8878 // corresponds to these arguments.
8879 if (isPartialSpecialization) {
8880 if (CheckTemplatePartialSpecializationArgs(TemplateNameLoc, ClassTemplate,
8881 TemplateArgs.size(),
8882 CanonicalConverted))
8883 return true;
8885 // FIXME: Move this to CheckTemplatePartialSpecializationArgs so we
8886 // also do it during instantiation.
8887 if (!Name.isDependent() &&
8888 !TemplateSpecializationType::anyDependentTemplateArguments(
8889 TemplateArgs, CanonicalConverted)) {
8890 Diag(TemplateNameLoc, diag::err_partial_spec_fully_specialized)
8891 << ClassTemplate->getDeclName();
8892 isPartialSpecialization = false;
8896 void *InsertPos = nullptr;
8897 ClassTemplateSpecializationDecl *PrevDecl = nullptr;
8899 if (isPartialSpecialization)
8900 PrevDecl = ClassTemplate->findPartialSpecialization(
8901 CanonicalConverted, TemplateParams, InsertPos);
8902 else
8903 PrevDecl = ClassTemplate->findSpecialization(CanonicalConverted, InsertPos);
8905 ClassTemplateSpecializationDecl *Specialization = nullptr;
8907 // Check whether we can declare a class template specialization in
8908 // the current scope.
8909 if (TUK != TUK_Friend &&
8910 CheckTemplateSpecializationScope(*this, ClassTemplate, PrevDecl,
8911 TemplateNameLoc,
8912 isPartialSpecialization))
8913 return true;
8915 // The canonical type
8916 QualType CanonType;
8917 if (isPartialSpecialization) {
8918 // Build the canonical type that describes the converted template
8919 // arguments of the class template partial specialization.
8920 TemplateName CanonTemplate = Context.getCanonicalTemplateName(Name);
8921 CanonType = Context.getTemplateSpecializationType(CanonTemplate,
8922 CanonicalConverted);
8924 if (Context.hasSameType(CanonType,
8925 ClassTemplate->getInjectedClassNameSpecialization()) &&
8926 (!Context.getLangOpts().CPlusPlus20 ||
8927 !TemplateParams->hasAssociatedConstraints())) {
8928 // C++ [temp.class.spec]p9b3:
8930 // -- The argument list of the specialization shall not be identical
8931 // to the implicit argument list of the primary template.
8933 // This rule has since been removed, because it's redundant given DR1495,
8934 // but we keep it because it produces better diagnostics and recovery.
8935 Diag(TemplateNameLoc, diag::err_partial_spec_args_match_primary_template)
8936 << /*class template*/0 << (TUK == TUK_Definition)
8937 << FixItHint::CreateRemoval(SourceRange(LAngleLoc, RAngleLoc));
8938 return CheckClassTemplate(S, TagSpec, TUK, KWLoc, SS,
8939 ClassTemplate->getIdentifier(),
8940 TemplateNameLoc,
8941 Attr,
8942 TemplateParams,
8943 AS_none, /*ModulePrivateLoc=*/SourceLocation(),
8944 /*FriendLoc*/SourceLocation(),
8945 TemplateParameterLists.size() - 1,
8946 TemplateParameterLists.data());
8949 // Create a new class template partial specialization declaration node.
8950 ClassTemplatePartialSpecializationDecl *PrevPartial
8951 = cast_or_null<ClassTemplatePartialSpecializationDecl>(PrevDecl);
8952 ClassTemplatePartialSpecializationDecl *Partial =
8953 ClassTemplatePartialSpecializationDecl::Create(
8954 Context, Kind, ClassTemplate->getDeclContext(), KWLoc,
8955 TemplateNameLoc, TemplateParams, ClassTemplate, CanonicalConverted,
8956 TemplateArgs, CanonType, PrevPartial);
8957 SetNestedNameSpecifier(*this, Partial, SS);
8958 if (TemplateParameterLists.size() > 1 && SS.isSet()) {
8959 Partial->setTemplateParameterListsInfo(
8960 Context, TemplateParameterLists.drop_back(1));
8963 if (!PrevPartial)
8964 ClassTemplate->AddPartialSpecialization(Partial, InsertPos);
8965 Specialization = Partial;
8967 // If we are providing an explicit specialization of a member class
8968 // template specialization, make a note of that.
8969 if (PrevPartial && PrevPartial->getInstantiatedFromMember())
8970 PrevPartial->setMemberSpecialization();
8972 CheckTemplatePartialSpecialization(Partial);
8973 } else {
8974 // Create a new class template specialization declaration node for
8975 // this explicit specialization or friend declaration.
8976 Specialization = ClassTemplateSpecializationDecl::Create(
8977 Context, Kind, ClassTemplate->getDeclContext(), KWLoc, TemplateNameLoc,
8978 ClassTemplate, CanonicalConverted, PrevDecl);
8979 SetNestedNameSpecifier(*this, Specialization, SS);
8980 if (TemplateParameterLists.size() > 0) {
8981 Specialization->setTemplateParameterListsInfo(Context,
8982 TemplateParameterLists);
8985 if (!PrevDecl)
8986 ClassTemplate->AddSpecialization(Specialization, InsertPos);
8988 if (CurContext->isDependentContext()) {
8989 TemplateName CanonTemplate = Context.getCanonicalTemplateName(Name);
8990 CanonType = Context.getTemplateSpecializationType(CanonTemplate,
8991 CanonicalConverted);
8992 } else {
8993 CanonType = Context.getTypeDeclType(Specialization);
8997 // C++ [temp.expl.spec]p6:
8998 // If a template, a member template or the member of a class template is
8999 // explicitly specialized then that specialization shall be declared
9000 // before the first use of that specialization that would cause an implicit
9001 // instantiation to take place, in every translation unit in which such a
9002 // use occurs; no diagnostic is required.
9003 if (PrevDecl && PrevDecl->getPointOfInstantiation().isValid()) {
9004 bool Okay = false;
9005 for (Decl *Prev = PrevDecl; Prev; Prev = Prev->getPreviousDecl()) {
9006 // Is there any previous explicit specialization declaration?
9007 if (getTemplateSpecializationKind(Prev) == TSK_ExplicitSpecialization) {
9008 Okay = true;
9009 break;
9013 if (!Okay) {
9014 SourceRange Range(TemplateNameLoc, RAngleLoc);
9015 Diag(TemplateNameLoc, diag::err_specialization_after_instantiation)
9016 << Context.getTypeDeclType(Specialization) << Range;
9018 Diag(PrevDecl->getPointOfInstantiation(),
9019 diag::note_instantiation_required_here)
9020 << (PrevDecl->getTemplateSpecializationKind()
9021 != TSK_ImplicitInstantiation);
9022 return true;
9026 // If this is not a friend, note that this is an explicit specialization.
9027 if (TUK != TUK_Friend)
9028 Specialization->setSpecializationKind(TSK_ExplicitSpecialization);
9030 // Check that this isn't a redefinition of this specialization.
9031 if (TUK == TUK_Definition) {
9032 RecordDecl *Def = Specialization->getDefinition();
9033 NamedDecl *Hidden = nullptr;
9034 if (Def && SkipBody && !hasVisibleDefinition(Def, &Hidden)) {
9035 SkipBody->ShouldSkip = true;
9036 SkipBody->Previous = Def;
9037 makeMergedDefinitionVisible(Hidden);
9038 } else if (Def) {
9039 SourceRange Range(TemplateNameLoc, RAngleLoc);
9040 Diag(TemplateNameLoc, diag::err_redefinition) << Specialization << Range;
9041 Diag(Def->getLocation(), diag::note_previous_definition);
9042 Specialization->setInvalidDecl();
9043 return true;
9047 ProcessDeclAttributeList(S, Specialization, Attr);
9049 // Add alignment attributes if necessary; these attributes are checked when
9050 // the ASTContext lays out the structure.
9051 if (TUK == TUK_Definition && (!SkipBody || !SkipBody->ShouldSkip)) {
9052 AddAlignmentAttributesForRecord(Specialization);
9053 AddMsStructLayoutForRecord(Specialization);
9056 if (ModulePrivateLoc.isValid())
9057 Diag(Specialization->getLocation(), diag::err_module_private_specialization)
9058 << (isPartialSpecialization? 1 : 0)
9059 << FixItHint::CreateRemoval(ModulePrivateLoc);
9061 // Build the fully-sugared type for this class template
9062 // specialization as the user wrote in the specialization
9063 // itself. This means that we'll pretty-print the type retrieved
9064 // from the specialization's declaration the way that the user
9065 // actually wrote the specialization, rather than formatting the
9066 // name based on the "canonical" representation used to store the
9067 // template arguments in the specialization.
9068 TypeSourceInfo *WrittenTy
9069 = Context.getTemplateSpecializationTypeInfo(Name, TemplateNameLoc,
9070 TemplateArgs, CanonType);
9071 if (TUK != TUK_Friend) {
9072 Specialization->setTypeAsWritten(WrittenTy);
9073 Specialization->setTemplateKeywordLoc(TemplateKWLoc);
9076 // C++ [temp.expl.spec]p9:
9077 // A template explicit specialization is in the scope of the
9078 // namespace in which the template was defined.
9080 // We actually implement this paragraph where we set the semantic
9081 // context (in the creation of the ClassTemplateSpecializationDecl),
9082 // but we also maintain the lexical context where the actual
9083 // definition occurs.
9084 Specialization->setLexicalDeclContext(CurContext);
9086 // We may be starting the definition of this specialization.
9087 if (TUK == TUK_Definition && (!SkipBody || !SkipBody->ShouldSkip))
9088 Specialization->startDefinition();
9090 if (TUK == TUK_Friend) {
9091 FriendDecl *Friend = FriendDecl::Create(Context, CurContext,
9092 TemplateNameLoc,
9093 WrittenTy,
9094 /*FIXME:*/KWLoc);
9095 Friend->setAccess(AS_public);
9096 CurContext->addDecl(Friend);
9097 } else {
9098 // Add the specialization into its lexical context, so that it can
9099 // be seen when iterating through the list of declarations in that
9100 // context. However, specializations are not found by name lookup.
9101 CurContext->addDecl(Specialization);
9104 if (SkipBody && SkipBody->ShouldSkip)
9105 return SkipBody->Previous;
9107 return Specialization;
9110 Decl *Sema::ActOnTemplateDeclarator(Scope *S,
9111 MultiTemplateParamsArg TemplateParameterLists,
9112 Declarator &D) {
9113 Decl *NewDecl = HandleDeclarator(S, D, TemplateParameterLists);
9114 ActOnDocumentableDecl(NewDecl);
9115 return NewDecl;
9118 Decl *Sema::ActOnConceptDefinition(Scope *S,
9119 MultiTemplateParamsArg TemplateParameterLists,
9120 IdentifierInfo *Name, SourceLocation NameLoc,
9121 Expr *ConstraintExpr) {
9122 DeclContext *DC = CurContext;
9124 if (!DC->getRedeclContext()->isFileContext()) {
9125 Diag(NameLoc,
9126 diag::err_concept_decls_may_only_appear_in_global_namespace_scope);
9127 return nullptr;
9130 if (TemplateParameterLists.size() > 1) {
9131 Diag(NameLoc, diag::err_concept_extra_headers);
9132 return nullptr;
9135 TemplateParameterList *Params = TemplateParameterLists.front();
9137 if (Params->size() == 0) {
9138 Diag(NameLoc, diag::err_concept_no_parameters);
9139 return nullptr;
9142 // Ensure that the parameter pack, if present, is the last parameter in the
9143 // template.
9144 for (TemplateParameterList::const_iterator ParamIt = Params->begin(),
9145 ParamEnd = Params->end();
9146 ParamIt != ParamEnd; ++ParamIt) {
9147 Decl const *Param = *ParamIt;
9148 if (Param->isParameterPack()) {
9149 if (++ParamIt == ParamEnd)
9150 break;
9151 Diag(Param->getLocation(),
9152 diag::err_template_param_pack_must_be_last_template_parameter);
9153 return nullptr;
9157 if (DiagnoseUnexpandedParameterPack(ConstraintExpr))
9158 return nullptr;
9160 ConceptDecl *NewDecl =
9161 ConceptDecl::Create(Context, DC, NameLoc, Name, Params, ConstraintExpr);
9163 if (NewDecl->hasAssociatedConstraints()) {
9164 // C++2a [temp.concept]p4:
9165 // A concept shall not have associated constraints.
9166 Diag(NameLoc, diag::err_concept_no_associated_constraints);
9167 NewDecl->setInvalidDecl();
9170 // Check for conflicting previous declaration.
9171 DeclarationNameInfo NameInfo(NewDecl->getDeclName(), NameLoc);
9172 LookupResult Previous(*this, NameInfo, LookupOrdinaryName,
9173 forRedeclarationInCurContext());
9174 LookupName(Previous, S);
9175 FilterLookupForScope(Previous, DC, S, /*ConsiderLinkage=*/false,
9176 /*AllowInlineNamespace*/false);
9177 bool AddToScope = true;
9178 CheckConceptRedefinition(NewDecl, Previous, AddToScope);
9180 ActOnDocumentableDecl(NewDecl);
9181 if (AddToScope)
9182 PushOnScopeChains(NewDecl, S);
9183 return NewDecl;
9186 void Sema::CheckConceptRedefinition(ConceptDecl *NewDecl,
9187 LookupResult &Previous, bool &AddToScope) {
9188 AddToScope = true;
9190 if (Previous.empty())
9191 return;
9193 auto *OldConcept = dyn_cast<ConceptDecl>(Previous.getRepresentativeDecl()->getUnderlyingDecl());
9194 if (!OldConcept) {
9195 auto *Old = Previous.getRepresentativeDecl();
9196 Diag(NewDecl->getLocation(), diag::err_redefinition_different_kind)
9197 << NewDecl->getDeclName();
9198 notePreviousDefinition(Old, NewDecl->getLocation());
9199 AddToScope = false;
9200 return;
9202 // Check if we can merge with a concept declaration.
9203 bool IsSame = Context.isSameEntity(NewDecl, OldConcept);
9204 if (!IsSame) {
9205 Diag(NewDecl->getLocation(), diag::err_redefinition_different_concept)
9206 << NewDecl->getDeclName();
9207 notePreviousDefinition(OldConcept, NewDecl->getLocation());
9208 AddToScope = false;
9209 return;
9211 if (hasReachableDefinition(OldConcept) &&
9212 IsRedefinitionInModule(NewDecl, OldConcept)) {
9213 Diag(NewDecl->getLocation(), diag::err_redefinition)
9214 << NewDecl->getDeclName();
9215 notePreviousDefinition(OldConcept, NewDecl->getLocation());
9216 AddToScope = false;
9217 return;
9219 if (!Previous.isSingleResult()) {
9220 // FIXME: we should produce an error in case of ambig and failed lookups.
9221 // Other decls (e.g. namespaces) also have this shortcoming.
9222 return;
9224 // We unwrap canonical decl late to check for module visibility.
9225 Context.setPrimaryMergedDecl(NewDecl, OldConcept->getCanonicalDecl());
9228 /// \brief Strips various properties off an implicit instantiation
9229 /// that has just been explicitly specialized.
9230 static void StripImplicitInstantiation(NamedDecl *D, bool MinGW) {
9231 if (MinGW || (isa<FunctionDecl>(D) &&
9232 cast<FunctionDecl>(D)->isFunctionTemplateSpecialization())) {
9233 D->dropAttr<DLLImportAttr>();
9234 D->dropAttr<DLLExportAttr>();
9237 if (FunctionDecl *FD = dyn_cast<FunctionDecl>(D))
9238 FD->setInlineSpecified(false);
9241 /// Compute the diagnostic location for an explicit instantiation
9242 // declaration or definition.
9243 static SourceLocation DiagLocForExplicitInstantiation(
9244 NamedDecl* D, SourceLocation PointOfInstantiation) {
9245 // Explicit instantiations following a specialization have no effect and
9246 // hence no PointOfInstantiation. In that case, walk decl backwards
9247 // until a valid name loc is found.
9248 SourceLocation PrevDiagLoc = PointOfInstantiation;
9249 for (Decl *Prev = D; Prev && !PrevDiagLoc.isValid();
9250 Prev = Prev->getPreviousDecl()) {
9251 PrevDiagLoc = Prev->getLocation();
9253 assert(PrevDiagLoc.isValid() &&
9254 "Explicit instantiation without point of instantiation?");
9255 return PrevDiagLoc;
9258 /// Diagnose cases where we have an explicit template specialization
9259 /// before/after an explicit template instantiation, producing diagnostics
9260 /// for those cases where they are required and determining whether the
9261 /// new specialization/instantiation will have any effect.
9263 /// \param NewLoc the location of the new explicit specialization or
9264 /// instantiation.
9266 /// \param NewTSK the kind of the new explicit specialization or instantiation.
9268 /// \param PrevDecl the previous declaration of the entity.
9270 /// \param PrevTSK the kind of the old explicit specialization or instantiatin.
9272 /// \param PrevPointOfInstantiation if valid, indicates where the previous
9273 /// declaration was instantiated (either implicitly or explicitly).
9275 /// \param HasNoEffect will be set to true to indicate that the new
9276 /// specialization or instantiation has no effect and should be ignored.
9278 /// \returns true if there was an error that should prevent the introduction of
9279 /// the new declaration into the AST, false otherwise.
9280 bool
9281 Sema::CheckSpecializationInstantiationRedecl(SourceLocation NewLoc,
9282 TemplateSpecializationKind NewTSK,
9283 NamedDecl *PrevDecl,
9284 TemplateSpecializationKind PrevTSK,
9285 SourceLocation PrevPointOfInstantiation,
9286 bool &HasNoEffect) {
9287 HasNoEffect = false;
9289 switch (NewTSK) {
9290 case TSK_Undeclared:
9291 case TSK_ImplicitInstantiation:
9292 assert(
9293 (PrevTSK == TSK_Undeclared || PrevTSK == TSK_ImplicitInstantiation) &&
9294 "previous declaration must be implicit!");
9295 return false;
9297 case TSK_ExplicitSpecialization:
9298 switch (PrevTSK) {
9299 case TSK_Undeclared:
9300 case TSK_ExplicitSpecialization:
9301 // Okay, we're just specializing something that is either already
9302 // explicitly specialized or has merely been mentioned without any
9303 // instantiation.
9304 return false;
9306 case TSK_ImplicitInstantiation:
9307 if (PrevPointOfInstantiation.isInvalid()) {
9308 // The declaration itself has not actually been instantiated, so it is
9309 // still okay to specialize it.
9310 StripImplicitInstantiation(
9311 PrevDecl,
9312 Context.getTargetInfo().getTriple().isWindowsGNUEnvironment());
9313 return false;
9315 // Fall through
9316 [[fallthrough]];
9318 case TSK_ExplicitInstantiationDeclaration:
9319 case TSK_ExplicitInstantiationDefinition:
9320 assert((PrevTSK == TSK_ImplicitInstantiation ||
9321 PrevPointOfInstantiation.isValid()) &&
9322 "Explicit instantiation without point of instantiation?");
9324 // C++ [temp.expl.spec]p6:
9325 // If a template, a member template or the member of a class template
9326 // is explicitly specialized then that specialization shall be declared
9327 // before the first use of that specialization that would cause an
9328 // implicit instantiation to take place, in every translation unit in
9329 // which such a use occurs; no diagnostic is required.
9330 for (Decl *Prev = PrevDecl; Prev; Prev = Prev->getPreviousDecl()) {
9331 // Is there any previous explicit specialization declaration?
9332 if (getTemplateSpecializationKind(Prev) == TSK_ExplicitSpecialization)
9333 return false;
9336 Diag(NewLoc, diag::err_specialization_after_instantiation)
9337 << PrevDecl;
9338 Diag(PrevPointOfInstantiation, diag::note_instantiation_required_here)
9339 << (PrevTSK != TSK_ImplicitInstantiation);
9341 return true;
9343 llvm_unreachable("The switch over PrevTSK must be exhaustive.");
9345 case TSK_ExplicitInstantiationDeclaration:
9346 switch (PrevTSK) {
9347 case TSK_ExplicitInstantiationDeclaration:
9348 // This explicit instantiation declaration is redundant (that's okay).
9349 HasNoEffect = true;
9350 return false;
9352 case TSK_Undeclared:
9353 case TSK_ImplicitInstantiation:
9354 // We're explicitly instantiating something that may have already been
9355 // implicitly instantiated; that's fine.
9356 return false;
9358 case TSK_ExplicitSpecialization:
9359 // C++0x [temp.explicit]p4:
9360 // For a given set of template parameters, if an explicit instantiation
9361 // of a template appears after a declaration of an explicit
9362 // specialization for that template, the explicit instantiation has no
9363 // effect.
9364 HasNoEffect = true;
9365 return false;
9367 case TSK_ExplicitInstantiationDefinition:
9368 // C++0x [temp.explicit]p10:
9369 // If an entity is the subject of both an explicit instantiation
9370 // declaration and an explicit instantiation definition in the same
9371 // translation unit, the definition shall follow the declaration.
9372 Diag(NewLoc,
9373 diag::err_explicit_instantiation_declaration_after_definition);
9375 // Explicit instantiations following a specialization have no effect and
9376 // hence no PrevPointOfInstantiation. In that case, walk decl backwards
9377 // until a valid name loc is found.
9378 Diag(DiagLocForExplicitInstantiation(PrevDecl, PrevPointOfInstantiation),
9379 diag::note_explicit_instantiation_definition_here);
9380 HasNoEffect = true;
9381 return false;
9383 llvm_unreachable("Unexpected TemplateSpecializationKind!");
9385 case TSK_ExplicitInstantiationDefinition:
9386 switch (PrevTSK) {
9387 case TSK_Undeclared:
9388 case TSK_ImplicitInstantiation:
9389 // We're explicitly instantiating something that may have already been
9390 // implicitly instantiated; that's fine.
9391 return false;
9393 case TSK_ExplicitSpecialization:
9394 // C++ DR 259, C++0x [temp.explicit]p4:
9395 // For a given set of template parameters, if an explicit
9396 // instantiation of a template appears after a declaration of
9397 // an explicit specialization for that template, the explicit
9398 // instantiation has no effect.
9399 Diag(NewLoc, diag::warn_explicit_instantiation_after_specialization)
9400 << PrevDecl;
9401 Diag(PrevDecl->getLocation(),
9402 diag::note_previous_template_specialization);
9403 HasNoEffect = true;
9404 return false;
9406 case TSK_ExplicitInstantiationDeclaration:
9407 // We're explicitly instantiating a definition for something for which we
9408 // were previously asked to suppress instantiations. That's fine.
9410 // C++0x [temp.explicit]p4:
9411 // For a given set of template parameters, if an explicit instantiation
9412 // of a template appears after a declaration of an explicit
9413 // specialization for that template, the explicit instantiation has no
9414 // effect.
9415 for (Decl *Prev = PrevDecl; Prev; Prev = Prev->getPreviousDecl()) {
9416 // Is there any previous explicit specialization declaration?
9417 if (getTemplateSpecializationKind(Prev) == TSK_ExplicitSpecialization) {
9418 HasNoEffect = true;
9419 break;
9423 return false;
9425 case TSK_ExplicitInstantiationDefinition:
9426 // C++0x [temp.spec]p5:
9427 // For a given template and a given set of template-arguments,
9428 // - an explicit instantiation definition shall appear at most once
9429 // in a program,
9431 // MSVCCompat: MSVC silently ignores duplicate explicit instantiations.
9432 Diag(NewLoc, (getLangOpts().MSVCCompat)
9433 ? diag::ext_explicit_instantiation_duplicate
9434 : diag::err_explicit_instantiation_duplicate)
9435 << PrevDecl;
9436 Diag(DiagLocForExplicitInstantiation(PrevDecl, PrevPointOfInstantiation),
9437 diag::note_previous_explicit_instantiation);
9438 HasNoEffect = true;
9439 return false;
9443 llvm_unreachable("Missing specialization/instantiation case?");
9446 /// Perform semantic analysis for the given dependent function
9447 /// template specialization.
9449 /// The only possible way to get a dependent function template specialization
9450 /// is with a friend declaration, like so:
9452 /// \code
9453 /// template \<class T> void foo(T);
9454 /// template \<class T> class A {
9455 /// friend void foo<>(T);
9456 /// };
9457 /// \endcode
9459 /// There really isn't any useful analysis we can do here, so we
9460 /// just store the information.
9461 bool Sema::CheckDependentFunctionTemplateSpecialization(
9462 FunctionDecl *FD, const TemplateArgumentListInfo *ExplicitTemplateArgs,
9463 LookupResult &Previous) {
9464 // Remove anything from Previous that isn't a function template in
9465 // the correct context.
9466 DeclContext *FDLookupContext = FD->getDeclContext()->getRedeclContext();
9467 LookupResult::Filter F = Previous.makeFilter();
9468 enum DiscardReason { NotAFunctionTemplate, NotAMemberOfEnclosing };
9469 SmallVector<std::pair<DiscardReason, Decl *>, 8> DiscardedCandidates;
9470 while (F.hasNext()) {
9471 NamedDecl *D = F.next()->getUnderlyingDecl();
9472 if (!isa<FunctionTemplateDecl>(D)) {
9473 F.erase();
9474 DiscardedCandidates.push_back(std::make_pair(NotAFunctionTemplate, D));
9475 continue;
9478 if (!FDLookupContext->InEnclosingNamespaceSetOf(
9479 D->getDeclContext()->getRedeclContext())) {
9480 F.erase();
9481 DiscardedCandidates.push_back(std::make_pair(NotAMemberOfEnclosing, D));
9482 continue;
9485 F.done();
9487 bool IsFriend = FD->getFriendObjectKind() != Decl::FOK_None;
9488 if (Previous.empty()) {
9489 Diag(FD->getLocation(), diag::err_dependent_function_template_spec_no_match)
9490 << IsFriend;
9491 for (auto &P : DiscardedCandidates)
9492 Diag(P.second->getLocation(),
9493 diag::note_dependent_function_template_spec_discard_reason)
9494 << P.first << IsFriend;
9495 return true;
9498 FD->setDependentTemplateSpecialization(Context, Previous.asUnresolvedSet(),
9499 ExplicitTemplateArgs);
9500 return false;
9503 /// Perform semantic analysis for the given function template
9504 /// specialization.
9506 /// This routine performs all of the semantic analysis required for an
9507 /// explicit function template specialization. On successful completion,
9508 /// the function declaration \p FD will become a function template
9509 /// specialization.
9511 /// \param FD the function declaration, which will be updated to become a
9512 /// function template specialization.
9514 /// \param ExplicitTemplateArgs the explicitly-provided template arguments,
9515 /// if any. Note that this may be valid info even when 0 arguments are
9516 /// explicitly provided as in, e.g., \c void sort<>(char*, char*);
9517 /// as it anyway contains info on the angle brackets locations.
9519 /// \param Previous the set of declarations that may be specialized by
9520 /// this function specialization.
9522 /// \param QualifiedFriend whether this is a lookup for a qualified friend
9523 /// declaration with no explicit template argument list that might be
9524 /// befriending a function template specialization.
9525 bool Sema::CheckFunctionTemplateSpecialization(
9526 FunctionDecl *FD, TemplateArgumentListInfo *ExplicitTemplateArgs,
9527 LookupResult &Previous, bool QualifiedFriend) {
9528 // The set of function template specializations that could match this
9529 // explicit function template specialization.
9530 UnresolvedSet<8> Candidates;
9531 TemplateSpecCandidateSet FailedCandidates(FD->getLocation(),
9532 /*ForTakingAddress=*/false);
9534 llvm::SmallDenseMap<FunctionDecl *, TemplateArgumentListInfo, 8>
9535 ConvertedTemplateArgs;
9537 DeclContext *FDLookupContext = FD->getDeclContext()->getRedeclContext();
9538 for (LookupResult::iterator I = Previous.begin(), E = Previous.end();
9539 I != E; ++I) {
9540 NamedDecl *Ovl = (*I)->getUnderlyingDecl();
9541 if (FunctionTemplateDecl *FunTmpl = dyn_cast<FunctionTemplateDecl>(Ovl)) {
9542 // Only consider templates found within the same semantic lookup scope as
9543 // FD.
9544 if (!FDLookupContext->InEnclosingNamespaceSetOf(
9545 Ovl->getDeclContext()->getRedeclContext()))
9546 continue;
9548 // When matching a constexpr member function template specialization
9549 // against the primary template, we don't yet know whether the
9550 // specialization has an implicit 'const' (because we don't know whether
9551 // it will be a static member function until we know which template it
9552 // specializes), so adjust it now assuming it specializes this template.
9553 QualType FT = FD->getType();
9554 if (FD->isConstexpr()) {
9555 CXXMethodDecl *OldMD =
9556 dyn_cast<CXXMethodDecl>(FunTmpl->getTemplatedDecl());
9557 if (OldMD && OldMD->isConst()) {
9558 const FunctionProtoType *FPT = FT->castAs<FunctionProtoType>();
9559 FunctionProtoType::ExtProtoInfo EPI = FPT->getExtProtoInfo();
9560 EPI.TypeQuals.addConst();
9561 FT = Context.getFunctionType(FPT->getReturnType(),
9562 FPT->getParamTypes(), EPI);
9566 TemplateArgumentListInfo Args;
9567 if (ExplicitTemplateArgs)
9568 Args = *ExplicitTemplateArgs;
9570 // C++ [temp.expl.spec]p11:
9571 // A trailing template-argument can be left unspecified in the
9572 // template-id naming an explicit function template specialization
9573 // provided it can be deduced from the function argument type.
9574 // Perform template argument deduction to determine whether we may be
9575 // specializing this template.
9576 // FIXME: It is somewhat wasteful to build
9577 TemplateDeductionInfo Info(FailedCandidates.getLocation());
9578 FunctionDecl *Specialization = nullptr;
9579 if (TemplateDeductionResult TDK = DeduceTemplateArguments(
9580 cast<FunctionTemplateDecl>(FunTmpl->getFirstDecl()),
9581 ExplicitTemplateArgs ? &Args : nullptr, FT, Specialization,
9582 Info)) {
9583 // Template argument deduction failed; record why it failed, so
9584 // that we can provide nifty diagnostics.
9585 FailedCandidates.addCandidate().set(
9586 I.getPair(), FunTmpl->getTemplatedDecl(),
9587 MakeDeductionFailureInfo(Context, TDK, Info));
9588 (void)TDK;
9589 continue;
9592 // Target attributes are part of the cuda function signature, so
9593 // the deduced template's cuda target must match that of the
9594 // specialization. Given that C++ template deduction does not
9595 // take target attributes into account, we reject candidates
9596 // here that have a different target.
9597 if (LangOpts.CUDA &&
9598 IdentifyCUDATarget(Specialization,
9599 /* IgnoreImplicitHDAttr = */ true) !=
9600 IdentifyCUDATarget(FD, /* IgnoreImplicitHDAttr = */ true)) {
9601 FailedCandidates.addCandidate().set(
9602 I.getPair(), FunTmpl->getTemplatedDecl(),
9603 MakeDeductionFailureInfo(Context, TDK_CUDATargetMismatch, Info));
9604 continue;
9607 // Record this candidate.
9608 if (ExplicitTemplateArgs)
9609 ConvertedTemplateArgs[Specialization] = std::move(Args);
9610 Candidates.addDecl(Specialization, I.getAccess());
9614 // For a qualified friend declaration (with no explicit marker to indicate
9615 // that a template specialization was intended), note all (template and
9616 // non-template) candidates.
9617 if (QualifiedFriend && Candidates.empty()) {
9618 Diag(FD->getLocation(), diag::err_qualified_friend_no_match)
9619 << FD->getDeclName() << FDLookupContext;
9620 // FIXME: We should form a single candidate list and diagnose all
9621 // candidates at once, to get proper sorting and limiting.
9622 for (auto *OldND : Previous) {
9623 if (auto *OldFD = dyn_cast<FunctionDecl>(OldND->getUnderlyingDecl()))
9624 NoteOverloadCandidate(OldND, OldFD, CRK_None, FD->getType(), false);
9626 FailedCandidates.NoteCandidates(*this, FD->getLocation());
9627 return true;
9630 // Find the most specialized function template.
9631 UnresolvedSetIterator Result = getMostSpecialized(
9632 Candidates.begin(), Candidates.end(), FailedCandidates, FD->getLocation(),
9633 PDiag(diag::err_function_template_spec_no_match) << FD->getDeclName(),
9634 PDiag(diag::err_function_template_spec_ambiguous)
9635 << FD->getDeclName() << (ExplicitTemplateArgs != nullptr),
9636 PDiag(diag::note_function_template_spec_matched));
9638 if (Result == Candidates.end())
9639 return true;
9641 // Ignore access information; it doesn't figure into redeclaration checking.
9642 FunctionDecl *Specialization = cast<FunctionDecl>(*Result);
9644 FunctionTemplateSpecializationInfo *SpecInfo
9645 = Specialization->getTemplateSpecializationInfo();
9646 assert(SpecInfo && "Function template specialization info missing?");
9648 // Note: do not overwrite location info if previous template
9649 // specialization kind was explicit.
9650 TemplateSpecializationKind TSK = SpecInfo->getTemplateSpecializationKind();
9651 if (TSK == TSK_Undeclared || TSK == TSK_ImplicitInstantiation) {
9652 Specialization->setLocation(FD->getLocation());
9653 Specialization->setLexicalDeclContext(FD->getLexicalDeclContext());
9654 // C++11 [dcl.constexpr]p1: An explicit specialization of a constexpr
9655 // function can differ from the template declaration with respect to
9656 // the constexpr specifier.
9657 // FIXME: We need an update record for this AST mutation.
9658 // FIXME: What if there are multiple such prior declarations (for instance,
9659 // from different modules)?
9660 Specialization->setConstexprKind(FD->getConstexprKind());
9663 // FIXME: Check if the prior specialization has a point of instantiation.
9664 // If so, we have run afoul of .
9666 // If this is a friend declaration, then we're not really declaring
9667 // an explicit specialization.
9668 bool isFriend = (FD->getFriendObjectKind() != Decl::FOK_None);
9670 // Check the scope of this explicit specialization.
9671 if (!isFriend &&
9672 CheckTemplateSpecializationScope(*this,
9673 Specialization->getPrimaryTemplate(),
9674 Specialization, FD->getLocation(),
9675 false))
9676 return true;
9678 // C++ [temp.expl.spec]p6:
9679 // If a template, a member template or the member of a class template is
9680 // explicitly specialized then that specialization shall be declared
9681 // before the first use of that specialization that would cause an implicit
9682 // instantiation to take place, in every translation unit in which such a
9683 // use occurs; no diagnostic is required.
9684 bool HasNoEffect = false;
9685 if (!isFriend &&
9686 CheckSpecializationInstantiationRedecl(FD->getLocation(),
9687 TSK_ExplicitSpecialization,
9688 Specialization,
9689 SpecInfo->getTemplateSpecializationKind(),
9690 SpecInfo->getPointOfInstantiation(),
9691 HasNoEffect))
9692 return true;
9694 // Mark the prior declaration as an explicit specialization, so that later
9695 // clients know that this is an explicit specialization.
9696 if (!isFriend) {
9697 // Since explicit specializations do not inherit '=delete' from their
9698 // primary function template - check if the 'specialization' that was
9699 // implicitly generated (during template argument deduction for partial
9700 // ordering) from the most specialized of all the function templates that
9701 // 'FD' could have been specializing, has a 'deleted' definition. If so,
9702 // first check that it was implicitly generated during template argument
9703 // deduction by making sure it wasn't referenced, and then reset the deleted
9704 // flag to not-deleted, so that we can inherit that information from 'FD'.
9705 if (Specialization->isDeleted() && !SpecInfo->isExplicitSpecialization() &&
9706 !Specialization->getCanonicalDecl()->isReferenced()) {
9707 // FIXME: This assert will not hold in the presence of modules.
9708 assert(
9709 Specialization->getCanonicalDecl() == Specialization &&
9710 "This must be the only existing declaration of this specialization");
9711 // FIXME: We need an update record for this AST mutation.
9712 Specialization->setDeletedAsWritten(false);
9714 // FIXME: We need an update record for this AST mutation.
9715 SpecInfo->setTemplateSpecializationKind(TSK_ExplicitSpecialization);
9716 MarkUnusedFileScopedDecl(Specialization);
9719 // Turn the given function declaration into a function template
9720 // specialization, with the template arguments from the previous
9721 // specialization.
9722 // Take copies of (semantic and syntactic) template argument lists.
9723 const TemplateArgumentList* TemplArgs = new (Context)
9724 TemplateArgumentList(Specialization->getTemplateSpecializationArgs());
9725 FD->setFunctionTemplateSpecialization(
9726 Specialization->getPrimaryTemplate(), TemplArgs, /*InsertPos=*/nullptr,
9727 SpecInfo->getTemplateSpecializationKind(),
9728 ExplicitTemplateArgs ? &ConvertedTemplateArgs[Specialization] : nullptr);
9730 // A function template specialization inherits the target attributes
9731 // of its template. (We require the attributes explicitly in the
9732 // code to match, but a template may have implicit attributes by
9733 // virtue e.g. of being constexpr, and it passes these implicit
9734 // attributes on to its specializations.)
9735 if (LangOpts.CUDA)
9736 inheritCUDATargetAttrs(FD, *Specialization->getPrimaryTemplate());
9738 // The "previous declaration" for this function template specialization is
9739 // the prior function template specialization.
9740 Previous.clear();
9741 Previous.addDecl(Specialization);
9742 return false;
9745 /// Perform semantic analysis for the given non-template member
9746 /// specialization.
9748 /// This routine performs all of the semantic analysis required for an
9749 /// explicit member function specialization. On successful completion,
9750 /// the function declaration \p FD will become a member function
9751 /// specialization.
9753 /// \param Member the member declaration, which will be updated to become a
9754 /// specialization.
9756 /// \param Previous the set of declarations, one of which may be specialized
9757 /// by this function specialization; the set will be modified to contain the
9758 /// redeclared member.
9759 bool
9760 Sema::CheckMemberSpecialization(NamedDecl *Member, LookupResult &Previous) {
9761 assert(!isa<TemplateDecl>(Member) && "Only for non-template members");
9763 // Try to find the member we are instantiating.
9764 NamedDecl *FoundInstantiation = nullptr;
9765 NamedDecl *Instantiation = nullptr;
9766 NamedDecl *InstantiatedFrom = nullptr;
9767 MemberSpecializationInfo *MSInfo = nullptr;
9769 if (Previous.empty()) {
9770 // Nowhere to look anyway.
9771 } else if (FunctionDecl *Function = dyn_cast<FunctionDecl>(Member)) {
9772 for (LookupResult::iterator I = Previous.begin(), E = Previous.end();
9773 I != E; ++I) {
9774 NamedDecl *D = (*I)->getUnderlyingDecl();
9775 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(D)) {
9776 QualType Adjusted = Function->getType();
9777 if (!hasExplicitCallingConv(Adjusted))
9778 Adjusted = adjustCCAndNoReturn(Adjusted, Method->getType());
9779 // This doesn't handle deduced return types, but both function
9780 // declarations should be undeduced at this point.
9781 if (Context.hasSameType(Adjusted, Method->getType())) {
9782 FoundInstantiation = *I;
9783 Instantiation = Method;
9784 InstantiatedFrom = Method->getInstantiatedFromMemberFunction();
9785 MSInfo = Method->getMemberSpecializationInfo();
9786 break;
9790 } else if (isa<VarDecl>(Member)) {
9791 VarDecl *PrevVar;
9792 if (Previous.isSingleResult() &&
9793 (PrevVar = dyn_cast<VarDecl>(Previous.getFoundDecl())))
9794 if (PrevVar->isStaticDataMember()) {
9795 FoundInstantiation = Previous.getRepresentativeDecl();
9796 Instantiation = PrevVar;
9797 InstantiatedFrom = PrevVar->getInstantiatedFromStaticDataMember();
9798 MSInfo = PrevVar->getMemberSpecializationInfo();
9800 } else if (isa<RecordDecl>(Member)) {
9801 CXXRecordDecl *PrevRecord;
9802 if (Previous.isSingleResult() &&
9803 (PrevRecord = dyn_cast<CXXRecordDecl>(Previous.getFoundDecl()))) {
9804 FoundInstantiation = Previous.getRepresentativeDecl();
9805 Instantiation = PrevRecord;
9806 InstantiatedFrom = PrevRecord->getInstantiatedFromMemberClass();
9807 MSInfo = PrevRecord->getMemberSpecializationInfo();
9809 } else if (isa<EnumDecl>(Member)) {
9810 EnumDecl *PrevEnum;
9811 if (Previous.isSingleResult() &&
9812 (PrevEnum = dyn_cast<EnumDecl>(Previous.getFoundDecl()))) {
9813 FoundInstantiation = Previous.getRepresentativeDecl();
9814 Instantiation = PrevEnum;
9815 InstantiatedFrom = PrevEnum->getInstantiatedFromMemberEnum();
9816 MSInfo = PrevEnum->getMemberSpecializationInfo();
9820 if (!Instantiation) {
9821 // There is no previous declaration that matches. Since member
9822 // specializations are always out-of-line, the caller will complain about
9823 // this mismatch later.
9824 return false;
9827 // A member specialization in a friend declaration isn't really declaring
9828 // an explicit specialization, just identifying a specific (possibly implicit)
9829 // specialization. Don't change the template specialization kind.
9831 // FIXME: Is this really valid? Other compilers reject.
9832 if (Member->getFriendObjectKind() != Decl::FOK_None) {
9833 // Preserve instantiation information.
9834 if (InstantiatedFrom && isa<CXXMethodDecl>(Member)) {
9835 cast<CXXMethodDecl>(Member)->setInstantiationOfMemberFunction(
9836 cast<CXXMethodDecl>(InstantiatedFrom),
9837 cast<CXXMethodDecl>(Instantiation)->getTemplateSpecializationKind());
9838 } else if (InstantiatedFrom && isa<CXXRecordDecl>(Member)) {
9839 cast<CXXRecordDecl>(Member)->setInstantiationOfMemberClass(
9840 cast<CXXRecordDecl>(InstantiatedFrom),
9841 cast<CXXRecordDecl>(Instantiation)->getTemplateSpecializationKind());
9844 Previous.clear();
9845 Previous.addDecl(FoundInstantiation);
9846 return false;
9849 // Make sure that this is a specialization of a member.
9850 if (!InstantiatedFrom) {
9851 Diag(Member->getLocation(), diag::err_spec_member_not_instantiated)
9852 << Member;
9853 Diag(Instantiation->getLocation(), diag::note_specialized_decl);
9854 return true;
9857 // C++ [temp.expl.spec]p6:
9858 // If a template, a member template or the member of a class template is
9859 // explicitly specialized then that specialization shall be declared
9860 // before the first use of that specialization that would cause an implicit
9861 // instantiation to take place, in every translation unit in which such a
9862 // use occurs; no diagnostic is required.
9863 assert(MSInfo && "Member specialization info missing?");
9865 bool HasNoEffect = false;
9866 if (CheckSpecializationInstantiationRedecl(Member->getLocation(),
9867 TSK_ExplicitSpecialization,
9868 Instantiation,
9869 MSInfo->getTemplateSpecializationKind(),
9870 MSInfo->getPointOfInstantiation(),
9871 HasNoEffect))
9872 return true;
9874 // Check the scope of this explicit specialization.
9875 if (CheckTemplateSpecializationScope(*this,
9876 InstantiatedFrom,
9877 Instantiation, Member->getLocation(),
9878 false))
9879 return true;
9881 // Note that this member specialization is an "instantiation of" the
9882 // corresponding member of the original template.
9883 if (auto *MemberFunction = dyn_cast<FunctionDecl>(Member)) {
9884 FunctionDecl *InstantiationFunction = cast<FunctionDecl>(Instantiation);
9885 if (InstantiationFunction->getTemplateSpecializationKind() ==
9886 TSK_ImplicitInstantiation) {
9887 // Explicit specializations of member functions of class templates do not
9888 // inherit '=delete' from the member function they are specializing.
9889 if (InstantiationFunction->isDeleted()) {
9890 // FIXME: This assert will not hold in the presence of modules.
9891 assert(InstantiationFunction->getCanonicalDecl() ==
9892 InstantiationFunction);
9893 // FIXME: We need an update record for this AST mutation.
9894 InstantiationFunction->setDeletedAsWritten(false);
9898 MemberFunction->setInstantiationOfMemberFunction(
9899 cast<CXXMethodDecl>(InstantiatedFrom), TSK_ExplicitSpecialization);
9900 } else if (auto *MemberVar = dyn_cast<VarDecl>(Member)) {
9901 MemberVar->setInstantiationOfStaticDataMember(
9902 cast<VarDecl>(InstantiatedFrom), TSK_ExplicitSpecialization);
9903 } else if (auto *MemberClass = dyn_cast<CXXRecordDecl>(Member)) {
9904 MemberClass->setInstantiationOfMemberClass(
9905 cast<CXXRecordDecl>(InstantiatedFrom), TSK_ExplicitSpecialization);
9906 } else if (auto *MemberEnum = dyn_cast<EnumDecl>(Member)) {
9907 MemberEnum->setInstantiationOfMemberEnum(
9908 cast<EnumDecl>(InstantiatedFrom), TSK_ExplicitSpecialization);
9909 } else {
9910 llvm_unreachable("unknown member specialization kind");
9913 // Save the caller the trouble of having to figure out which declaration
9914 // this specialization matches.
9915 Previous.clear();
9916 Previous.addDecl(FoundInstantiation);
9917 return false;
9920 /// Complete the explicit specialization of a member of a class template by
9921 /// updating the instantiated member to be marked as an explicit specialization.
9923 /// \param OrigD The member declaration instantiated from the template.
9924 /// \param Loc The location of the explicit specialization of the member.
9925 template<typename DeclT>
9926 static void completeMemberSpecializationImpl(Sema &S, DeclT *OrigD,
9927 SourceLocation Loc) {
9928 if (OrigD->getTemplateSpecializationKind() != TSK_ImplicitInstantiation)
9929 return;
9931 // FIXME: Inform AST mutation listeners of this AST mutation.
9932 // FIXME: If there are multiple in-class declarations of the member (from
9933 // multiple modules, or a declaration and later definition of a member type),
9934 // should we update all of them?
9935 OrigD->setTemplateSpecializationKind(TSK_ExplicitSpecialization);
9936 OrigD->setLocation(Loc);
9939 void Sema::CompleteMemberSpecialization(NamedDecl *Member,
9940 LookupResult &Previous) {
9941 NamedDecl *Instantiation = cast<NamedDecl>(Member->getCanonicalDecl());
9942 if (Instantiation == Member)
9943 return;
9945 if (auto *Function = dyn_cast<CXXMethodDecl>(Instantiation))
9946 completeMemberSpecializationImpl(*this, Function, Member->getLocation());
9947 else if (auto *Var = dyn_cast<VarDecl>(Instantiation))
9948 completeMemberSpecializationImpl(*this, Var, Member->getLocation());
9949 else if (auto *Record = dyn_cast<CXXRecordDecl>(Instantiation))
9950 completeMemberSpecializationImpl(*this, Record, Member->getLocation());
9951 else if (auto *Enum = dyn_cast<EnumDecl>(Instantiation))
9952 completeMemberSpecializationImpl(*this, Enum, Member->getLocation());
9953 else
9954 llvm_unreachable("unknown member specialization kind");
9957 /// Check the scope of an explicit instantiation.
9959 /// \returns true if a serious error occurs, false otherwise.
9960 static bool CheckExplicitInstantiationScope(Sema &S, NamedDecl *D,
9961 SourceLocation InstLoc,
9962 bool WasQualifiedName) {
9963 DeclContext *OrigContext= D->getDeclContext()->getEnclosingNamespaceContext();
9964 DeclContext *CurContext = S.CurContext->getRedeclContext();
9966 if (CurContext->isRecord()) {
9967 S.Diag(InstLoc, diag::err_explicit_instantiation_in_class)
9968 << D;
9969 return true;
9972 // C++11 [temp.explicit]p3:
9973 // An explicit instantiation shall appear in an enclosing namespace of its
9974 // template. If the name declared in the explicit instantiation is an
9975 // unqualified name, the explicit instantiation shall appear in the
9976 // namespace where its template is declared or, if that namespace is inline
9977 // (7.3.1), any namespace from its enclosing namespace set.
9979 // This is DR275, which we do not retroactively apply to C++98/03.
9980 if (WasQualifiedName) {
9981 if (CurContext->Encloses(OrigContext))
9982 return false;
9983 } else {
9984 if (CurContext->InEnclosingNamespaceSetOf(OrigContext))
9985 return false;
9988 if (NamespaceDecl *NS = dyn_cast<NamespaceDecl>(OrigContext)) {
9989 if (WasQualifiedName)
9990 S.Diag(InstLoc,
9991 S.getLangOpts().CPlusPlus11?
9992 diag::err_explicit_instantiation_out_of_scope :
9993 diag::warn_explicit_instantiation_out_of_scope_0x)
9994 << D << NS;
9995 else
9996 S.Diag(InstLoc,
9997 S.getLangOpts().CPlusPlus11?
9998 diag::err_explicit_instantiation_unqualified_wrong_namespace :
9999 diag::warn_explicit_instantiation_unqualified_wrong_namespace_0x)
10000 << D << NS;
10001 } else
10002 S.Diag(InstLoc,
10003 S.getLangOpts().CPlusPlus11?
10004 diag::err_explicit_instantiation_must_be_global :
10005 diag::warn_explicit_instantiation_must_be_global_0x)
10006 << D;
10007 S.Diag(D->getLocation(), diag::note_explicit_instantiation_here);
10008 return false;
10011 /// Common checks for whether an explicit instantiation of \p D is valid.
10012 static bool CheckExplicitInstantiation(Sema &S, NamedDecl *D,
10013 SourceLocation InstLoc,
10014 bool WasQualifiedName,
10015 TemplateSpecializationKind TSK) {
10016 // C++ [temp.explicit]p13:
10017 // An explicit instantiation declaration shall not name a specialization of
10018 // a template with internal linkage.
10019 if (TSK == TSK_ExplicitInstantiationDeclaration &&
10020 D->getFormalLinkage() == Linkage::Internal) {
10021 S.Diag(InstLoc, diag::err_explicit_instantiation_internal_linkage) << D;
10022 return true;
10025 // C++11 [temp.explicit]p3: [DR 275]
10026 // An explicit instantiation shall appear in an enclosing namespace of its
10027 // template.
10028 if (CheckExplicitInstantiationScope(S, D, InstLoc, WasQualifiedName))
10029 return true;
10031 return false;
10034 /// Determine whether the given scope specifier has a template-id in it.
10035 static bool ScopeSpecifierHasTemplateId(const CXXScopeSpec &SS) {
10036 if (!SS.isSet())
10037 return false;
10039 // C++11 [temp.explicit]p3:
10040 // If the explicit instantiation is for a member function, a member class
10041 // or a static data member of a class template specialization, the name of
10042 // the class template specialization in the qualified-id for the member
10043 // name shall be a simple-template-id.
10045 // C++98 has the same restriction, just worded differently.
10046 for (NestedNameSpecifier *NNS = SS.getScopeRep(); NNS;
10047 NNS = NNS->getPrefix())
10048 if (const Type *T = NNS->getAsType())
10049 if (isa<TemplateSpecializationType>(T))
10050 return true;
10052 return false;
10055 /// Make a dllexport or dllimport attr on a class template specialization take
10056 /// effect.
10057 static void dllExportImportClassTemplateSpecialization(
10058 Sema &S, ClassTemplateSpecializationDecl *Def) {
10059 auto *A = cast_or_null<InheritableAttr>(getDLLAttr(Def));
10060 assert(A && "dllExportImportClassTemplateSpecialization called "
10061 "on Def without dllexport or dllimport");
10063 // We reject explicit instantiations in class scope, so there should
10064 // never be any delayed exported classes to worry about.
10065 assert(S.DelayedDllExportClasses.empty() &&
10066 "delayed exports present at explicit instantiation");
10067 S.checkClassLevelDLLAttribute(Def);
10069 // Propagate attribute to base class templates.
10070 for (auto &B : Def->bases()) {
10071 if (auto *BT = dyn_cast_or_null<ClassTemplateSpecializationDecl>(
10072 B.getType()->getAsCXXRecordDecl()))
10073 S.propagateDLLAttrToBaseClassTemplate(Def, A, BT, B.getBeginLoc());
10076 S.referenceDLLExportedClassMethods();
10079 // Explicit instantiation of a class template specialization
10080 DeclResult Sema::ActOnExplicitInstantiation(
10081 Scope *S, SourceLocation ExternLoc, SourceLocation TemplateLoc,
10082 unsigned TagSpec, SourceLocation KWLoc, const CXXScopeSpec &SS,
10083 TemplateTy TemplateD, SourceLocation TemplateNameLoc,
10084 SourceLocation LAngleLoc, ASTTemplateArgsPtr TemplateArgsIn,
10085 SourceLocation RAngleLoc, const ParsedAttributesView &Attr) {
10086 // Find the class template we're specializing
10087 TemplateName Name = TemplateD.get();
10088 TemplateDecl *TD = Name.getAsTemplateDecl();
10089 // Check that the specialization uses the same tag kind as the
10090 // original template.
10091 TagTypeKind Kind = TypeWithKeyword::getTagTypeKindForTypeSpec(TagSpec);
10092 assert(Kind != TagTypeKind::Enum &&
10093 "Invalid enum tag in class template explicit instantiation!");
10095 ClassTemplateDecl *ClassTemplate = dyn_cast<ClassTemplateDecl>(TD);
10097 if (!ClassTemplate) {
10098 NonTagKind NTK = getNonTagTypeDeclKind(TD, Kind);
10099 Diag(TemplateNameLoc, diag::err_tag_reference_non_tag)
10100 << TD << NTK << llvm::to_underlying(Kind);
10101 Diag(TD->getLocation(), diag::note_previous_use);
10102 return true;
10105 if (!isAcceptableTagRedeclaration(ClassTemplate->getTemplatedDecl(),
10106 Kind, /*isDefinition*/false, KWLoc,
10107 ClassTemplate->getIdentifier())) {
10108 Diag(KWLoc, diag::err_use_with_wrong_tag)
10109 << ClassTemplate
10110 << FixItHint::CreateReplacement(KWLoc,
10111 ClassTemplate->getTemplatedDecl()->getKindName());
10112 Diag(ClassTemplate->getTemplatedDecl()->getLocation(),
10113 diag::note_previous_use);
10114 Kind = ClassTemplate->getTemplatedDecl()->getTagKind();
10117 // C++0x [temp.explicit]p2:
10118 // There are two forms of explicit instantiation: an explicit instantiation
10119 // definition and an explicit instantiation declaration. An explicit
10120 // instantiation declaration begins with the extern keyword. [...]
10121 TemplateSpecializationKind TSK = ExternLoc.isInvalid()
10122 ? TSK_ExplicitInstantiationDefinition
10123 : TSK_ExplicitInstantiationDeclaration;
10125 if (TSK == TSK_ExplicitInstantiationDeclaration &&
10126 !Context.getTargetInfo().getTriple().isWindowsGNUEnvironment()) {
10127 // Check for dllexport class template instantiation declarations,
10128 // except for MinGW mode.
10129 for (const ParsedAttr &AL : Attr) {
10130 if (AL.getKind() == ParsedAttr::AT_DLLExport) {
10131 Diag(ExternLoc,
10132 diag::warn_attribute_dllexport_explicit_instantiation_decl);
10133 Diag(AL.getLoc(), diag::note_attribute);
10134 break;
10138 if (auto *A = ClassTemplate->getTemplatedDecl()->getAttr<DLLExportAttr>()) {
10139 Diag(ExternLoc,
10140 diag::warn_attribute_dllexport_explicit_instantiation_decl);
10141 Diag(A->getLocation(), diag::note_attribute);
10145 // In MSVC mode, dllimported explicit instantiation definitions are treated as
10146 // instantiation declarations for most purposes.
10147 bool DLLImportExplicitInstantiationDef = false;
10148 if (TSK == TSK_ExplicitInstantiationDefinition &&
10149 Context.getTargetInfo().getCXXABI().isMicrosoft()) {
10150 // Check for dllimport class template instantiation definitions.
10151 bool DLLImport =
10152 ClassTemplate->getTemplatedDecl()->getAttr<DLLImportAttr>();
10153 for (const ParsedAttr &AL : Attr) {
10154 if (AL.getKind() == ParsedAttr::AT_DLLImport)
10155 DLLImport = true;
10156 if (AL.getKind() == ParsedAttr::AT_DLLExport) {
10157 // dllexport trumps dllimport here.
10158 DLLImport = false;
10159 break;
10162 if (DLLImport) {
10163 TSK = TSK_ExplicitInstantiationDeclaration;
10164 DLLImportExplicitInstantiationDef = true;
10168 // Translate the parser's template argument list in our AST format.
10169 TemplateArgumentListInfo TemplateArgs(LAngleLoc, RAngleLoc);
10170 translateTemplateArguments(TemplateArgsIn, TemplateArgs);
10172 // Check that the template argument list is well-formed for this
10173 // template.
10174 SmallVector<TemplateArgument, 4> SugaredConverted, CanonicalConverted;
10175 if (CheckTemplateArgumentList(ClassTemplate, TemplateNameLoc, TemplateArgs,
10176 false, SugaredConverted, CanonicalConverted,
10177 /*UpdateArgsWithConversions=*/true))
10178 return true;
10180 // Find the class template specialization declaration that
10181 // corresponds to these arguments.
10182 void *InsertPos = nullptr;
10183 ClassTemplateSpecializationDecl *PrevDecl =
10184 ClassTemplate->findSpecialization(CanonicalConverted, InsertPos);
10186 TemplateSpecializationKind PrevDecl_TSK
10187 = PrevDecl ? PrevDecl->getTemplateSpecializationKind() : TSK_Undeclared;
10189 if (TSK == TSK_ExplicitInstantiationDefinition && PrevDecl != nullptr &&
10190 Context.getTargetInfo().getTriple().isWindowsGNUEnvironment()) {
10191 // Check for dllexport class template instantiation definitions in MinGW
10192 // mode, if a previous declaration of the instantiation was seen.
10193 for (const ParsedAttr &AL : Attr) {
10194 if (AL.getKind() == ParsedAttr::AT_DLLExport) {
10195 Diag(AL.getLoc(),
10196 diag::warn_attribute_dllexport_explicit_instantiation_def);
10197 break;
10202 if (CheckExplicitInstantiation(*this, ClassTemplate, TemplateNameLoc,
10203 SS.isSet(), TSK))
10204 return true;
10206 ClassTemplateSpecializationDecl *Specialization = nullptr;
10208 bool HasNoEffect = false;
10209 if (PrevDecl) {
10210 if (CheckSpecializationInstantiationRedecl(TemplateNameLoc, TSK,
10211 PrevDecl, PrevDecl_TSK,
10212 PrevDecl->getPointOfInstantiation(),
10213 HasNoEffect))
10214 return PrevDecl;
10216 // Even though HasNoEffect == true means that this explicit instantiation
10217 // has no effect on semantics, we go on to put its syntax in the AST.
10219 if (PrevDecl_TSK == TSK_ImplicitInstantiation ||
10220 PrevDecl_TSK == TSK_Undeclared) {
10221 // Since the only prior class template specialization with these
10222 // arguments was referenced but not declared, reuse that
10223 // declaration node as our own, updating the source location
10224 // for the template name to reflect our new declaration.
10225 // (Other source locations will be updated later.)
10226 Specialization = PrevDecl;
10227 Specialization->setLocation(TemplateNameLoc);
10228 PrevDecl = nullptr;
10231 if (PrevDecl_TSK == TSK_ExplicitInstantiationDeclaration &&
10232 DLLImportExplicitInstantiationDef) {
10233 // The new specialization might add a dllimport attribute.
10234 HasNoEffect = false;
10238 if (!Specialization) {
10239 // Create a new class template specialization declaration node for
10240 // this explicit specialization.
10241 Specialization = ClassTemplateSpecializationDecl::Create(
10242 Context, Kind, ClassTemplate->getDeclContext(), KWLoc, TemplateNameLoc,
10243 ClassTemplate, CanonicalConverted, PrevDecl);
10244 SetNestedNameSpecifier(*this, Specialization, SS);
10246 // A MSInheritanceAttr attached to the previous declaration must be
10247 // propagated to the new node prior to instantiation.
10248 if (PrevDecl) {
10249 if (const auto *A = PrevDecl->getAttr<MSInheritanceAttr>()) {
10250 auto *Clone = A->clone(getASTContext());
10251 Clone->setInherited(true);
10252 Specialization->addAttr(Clone);
10253 Consumer.AssignInheritanceModel(Specialization);
10257 if (!HasNoEffect && !PrevDecl) {
10258 // Insert the new specialization.
10259 ClassTemplate->AddSpecialization(Specialization, InsertPos);
10263 // Build the fully-sugared type for this explicit instantiation as
10264 // the user wrote in the explicit instantiation itself. This means
10265 // that we'll pretty-print the type retrieved from the
10266 // specialization's declaration the way that the user actually wrote
10267 // the explicit instantiation, rather than formatting the name based
10268 // on the "canonical" representation used to store the template
10269 // arguments in the specialization.
10270 TypeSourceInfo *WrittenTy
10271 = Context.getTemplateSpecializationTypeInfo(Name, TemplateNameLoc,
10272 TemplateArgs,
10273 Context.getTypeDeclType(Specialization));
10274 Specialization->setTypeAsWritten(WrittenTy);
10276 // Set source locations for keywords.
10277 Specialization->setExternLoc(ExternLoc);
10278 Specialization->setTemplateKeywordLoc(TemplateLoc);
10279 Specialization->setBraceRange(SourceRange());
10281 bool PreviouslyDLLExported = Specialization->hasAttr<DLLExportAttr>();
10282 ProcessDeclAttributeList(S, Specialization, Attr);
10284 // Add the explicit instantiation into its lexical context. However,
10285 // since explicit instantiations are never found by name lookup, we
10286 // just put it into the declaration context directly.
10287 Specialization->setLexicalDeclContext(CurContext);
10288 CurContext->addDecl(Specialization);
10290 // Syntax is now OK, so return if it has no other effect on semantics.
10291 if (HasNoEffect) {
10292 // Set the template specialization kind.
10293 Specialization->setTemplateSpecializationKind(TSK);
10294 return Specialization;
10297 // C++ [temp.explicit]p3:
10298 // A definition of a class template or class member template
10299 // shall be in scope at the point of the explicit instantiation of
10300 // the class template or class member template.
10302 // This check comes when we actually try to perform the
10303 // instantiation.
10304 ClassTemplateSpecializationDecl *Def
10305 = cast_or_null<ClassTemplateSpecializationDecl>(
10306 Specialization->getDefinition());
10307 if (!Def)
10308 InstantiateClassTemplateSpecialization(TemplateNameLoc, Specialization, TSK);
10309 else if (TSK == TSK_ExplicitInstantiationDefinition) {
10310 MarkVTableUsed(TemplateNameLoc, Specialization, true);
10311 Specialization->setPointOfInstantiation(Def->getPointOfInstantiation());
10314 // Instantiate the members of this class template specialization.
10315 Def = cast_or_null<ClassTemplateSpecializationDecl>(
10316 Specialization->getDefinition());
10317 if (Def) {
10318 TemplateSpecializationKind Old_TSK = Def->getTemplateSpecializationKind();
10319 // Fix a TSK_ExplicitInstantiationDeclaration followed by a
10320 // TSK_ExplicitInstantiationDefinition
10321 if (Old_TSK == TSK_ExplicitInstantiationDeclaration &&
10322 (TSK == TSK_ExplicitInstantiationDefinition ||
10323 DLLImportExplicitInstantiationDef)) {
10324 // FIXME: Need to notify the ASTMutationListener that we did this.
10325 Def->setTemplateSpecializationKind(TSK);
10327 if (!getDLLAttr(Def) && getDLLAttr(Specialization) &&
10328 (Context.getTargetInfo().shouldDLLImportComdatSymbols() &&
10329 !Context.getTargetInfo().getTriple().isPS())) {
10330 // An explicit instantiation definition can add a dll attribute to a
10331 // template with a previous instantiation declaration. MinGW doesn't
10332 // allow this.
10333 auto *A = cast<InheritableAttr>(
10334 getDLLAttr(Specialization)->clone(getASTContext()));
10335 A->setInherited(true);
10336 Def->addAttr(A);
10337 dllExportImportClassTemplateSpecialization(*this, Def);
10341 // Fix a TSK_ImplicitInstantiation followed by a
10342 // TSK_ExplicitInstantiationDefinition
10343 bool NewlyDLLExported =
10344 !PreviouslyDLLExported && Specialization->hasAttr<DLLExportAttr>();
10345 if (Old_TSK == TSK_ImplicitInstantiation && NewlyDLLExported &&
10346 (Context.getTargetInfo().shouldDLLImportComdatSymbols() &&
10347 !Context.getTargetInfo().getTriple().isPS())) {
10348 // An explicit instantiation definition can add a dll attribute to a
10349 // template with a previous implicit instantiation. MinGW doesn't allow
10350 // this. We limit clang to only adding dllexport, to avoid potentially
10351 // strange codegen behavior. For example, if we extend this conditional
10352 // to dllimport, and we have a source file calling a method on an
10353 // implicitly instantiated template class instance and then declaring a
10354 // dllimport explicit instantiation definition for the same template
10355 // class, the codegen for the method call will not respect the dllimport,
10356 // while it will with cl. The Def will already have the DLL attribute,
10357 // since the Def and Specialization will be the same in the case of
10358 // Old_TSK == TSK_ImplicitInstantiation, and we already added the
10359 // attribute to the Specialization; we just need to make it take effect.
10360 assert(Def == Specialization &&
10361 "Def and Specialization should match for implicit instantiation");
10362 dllExportImportClassTemplateSpecialization(*this, Def);
10365 // In MinGW mode, export the template instantiation if the declaration
10366 // was marked dllexport.
10367 if (PrevDecl_TSK == TSK_ExplicitInstantiationDeclaration &&
10368 Context.getTargetInfo().getTriple().isWindowsGNUEnvironment() &&
10369 PrevDecl->hasAttr<DLLExportAttr>()) {
10370 dllExportImportClassTemplateSpecialization(*this, Def);
10373 // Set the template specialization kind. Make sure it is set before
10374 // instantiating the members which will trigger ASTConsumer callbacks.
10375 Specialization->setTemplateSpecializationKind(TSK);
10376 InstantiateClassTemplateSpecializationMembers(TemplateNameLoc, Def, TSK);
10377 } else {
10379 // Set the template specialization kind.
10380 Specialization->setTemplateSpecializationKind(TSK);
10383 return Specialization;
10386 // Explicit instantiation of a member class of a class template.
10387 DeclResult
10388 Sema::ActOnExplicitInstantiation(Scope *S, SourceLocation ExternLoc,
10389 SourceLocation TemplateLoc, unsigned TagSpec,
10390 SourceLocation KWLoc, CXXScopeSpec &SS,
10391 IdentifierInfo *Name, SourceLocation NameLoc,
10392 const ParsedAttributesView &Attr) {
10394 bool Owned = false;
10395 bool IsDependent = false;
10396 Decl *TagD = ActOnTag(S, TagSpec, Sema::TUK_Reference, KWLoc, SS, Name,
10397 NameLoc, Attr, AS_none, /*ModulePrivateLoc=*/SourceLocation(),
10398 MultiTemplateParamsArg(), Owned, IsDependent, SourceLocation(),
10399 false, TypeResult(), /*IsTypeSpecifier*/ false,
10400 /*IsTemplateParamOrArg*/ false, /*OOK=*/OOK_Outside).get();
10401 assert(!IsDependent && "explicit instantiation of dependent name not yet handled");
10403 if (!TagD)
10404 return true;
10406 TagDecl *Tag = cast<TagDecl>(TagD);
10407 assert(!Tag->isEnum() && "shouldn't see enumerations here");
10409 if (Tag->isInvalidDecl())
10410 return true;
10412 CXXRecordDecl *Record = cast<CXXRecordDecl>(Tag);
10413 CXXRecordDecl *Pattern = Record->getInstantiatedFromMemberClass();
10414 if (!Pattern) {
10415 Diag(TemplateLoc, diag::err_explicit_instantiation_nontemplate_type)
10416 << Context.getTypeDeclType(Record);
10417 Diag(Record->getLocation(), diag::note_nontemplate_decl_here);
10418 return true;
10421 // C++0x [temp.explicit]p2:
10422 // If the explicit instantiation is for a class or member class, the
10423 // elaborated-type-specifier in the declaration shall include a
10424 // simple-template-id.
10426 // C++98 has the same restriction, just worded differently.
10427 if (!ScopeSpecifierHasTemplateId(SS))
10428 Diag(TemplateLoc, diag::ext_explicit_instantiation_without_qualified_id)
10429 << Record << SS.getRange();
10431 // C++0x [temp.explicit]p2:
10432 // There are two forms of explicit instantiation: an explicit instantiation
10433 // definition and an explicit instantiation declaration. An explicit
10434 // instantiation declaration begins with the extern keyword. [...]
10435 TemplateSpecializationKind TSK
10436 = ExternLoc.isInvalid()? TSK_ExplicitInstantiationDefinition
10437 : TSK_ExplicitInstantiationDeclaration;
10439 CheckExplicitInstantiation(*this, Record, NameLoc, true, TSK);
10441 // Verify that it is okay to explicitly instantiate here.
10442 CXXRecordDecl *PrevDecl
10443 = cast_or_null<CXXRecordDecl>(Record->getPreviousDecl());
10444 if (!PrevDecl && Record->getDefinition())
10445 PrevDecl = Record;
10446 if (PrevDecl) {
10447 MemberSpecializationInfo *MSInfo = PrevDecl->getMemberSpecializationInfo();
10448 bool HasNoEffect = false;
10449 assert(MSInfo && "No member specialization information?");
10450 if (CheckSpecializationInstantiationRedecl(TemplateLoc, TSK,
10451 PrevDecl,
10452 MSInfo->getTemplateSpecializationKind(),
10453 MSInfo->getPointOfInstantiation(),
10454 HasNoEffect))
10455 return true;
10456 if (HasNoEffect)
10457 return TagD;
10460 CXXRecordDecl *RecordDef
10461 = cast_or_null<CXXRecordDecl>(Record->getDefinition());
10462 if (!RecordDef) {
10463 // C++ [temp.explicit]p3:
10464 // A definition of a member class of a class template shall be in scope
10465 // at the point of an explicit instantiation of the member class.
10466 CXXRecordDecl *Def
10467 = cast_or_null<CXXRecordDecl>(Pattern->getDefinition());
10468 if (!Def) {
10469 Diag(TemplateLoc, diag::err_explicit_instantiation_undefined_member)
10470 << 0 << Record->getDeclName() << Record->getDeclContext();
10471 Diag(Pattern->getLocation(), diag::note_forward_declaration)
10472 << Pattern;
10473 return true;
10474 } else {
10475 if (InstantiateClass(NameLoc, Record, Def,
10476 getTemplateInstantiationArgs(Record),
10477 TSK))
10478 return true;
10480 RecordDef = cast_or_null<CXXRecordDecl>(Record->getDefinition());
10481 if (!RecordDef)
10482 return true;
10486 // Instantiate all of the members of the class.
10487 InstantiateClassMembers(NameLoc, RecordDef,
10488 getTemplateInstantiationArgs(Record), TSK);
10490 if (TSK == TSK_ExplicitInstantiationDefinition)
10491 MarkVTableUsed(NameLoc, RecordDef, true);
10493 // FIXME: We don't have any representation for explicit instantiations of
10494 // member classes. Such a representation is not needed for compilation, but it
10495 // should be available for clients that want to see all of the declarations in
10496 // the source code.
10497 return TagD;
10500 DeclResult Sema::ActOnExplicitInstantiation(Scope *S,
10501 SourceLocation ExternLoc,
10502 SourceLocation TemplateLoc,
10503 Declarator &D) {
10504 // Explicit instantiations always require a name.
10505 // TODO: check if/when DNInfo should replace Name.
10506 DeclarationNameInfo NameInfo = GetNameForDeclarator(D);
10507 DeclarationName Name = NameInfo.getName();
10508 if (!Name) {
10509 if (!D.isInvalidType())
10510 Diag(D.getDeclSpec().getBeginLoc(),
10511 diag::err_explicit_instantiation_requires_name)
10512 << D.getDeclSpec().getSourceRange() << D.getSourceRange();
10514 return true;
10517 // The scope passed in may not be a decl scope. Zip up the scope tree until
10518 // we find one that is.
10519 while ((S->getFlags() & Scope::DeclScope) == 0 ||
10520 (S->getFlags() & Scope::TemplateParamScope) != 0)
10521 S = S->getParent();
10523 // Determine the type of the declaration.
10524 TypeSourceInfo *T = GetTypeForDeclarator(D, S);
10525 QualType R = T->getType();
10526 if (R.isNull())
10527 return true;
10529 // C++ [dcl.stc]p1:
10530 // A storage-class-specifier shall not be specified in [...] an explicit
10531 // instantiation (14.7.2) directive.
10532 if (D.getDeclSpec().getStorageClassSpec() == DeclSpec::SCS_typedef) {
10533 Diag(D.getIdentifierLoc(), diag::err_explicit_instantiation_of_typedef)
10534 << Name;
10535 return true;
10536 } else if (D.getDeclSpec().getStorageClassSpec()
10537 != DeclSpec::SCS_unspecified) {
10538 // Complain about then remove the storage class specifier.
10539 Diag(D.getIdentifierLoc(), diag::err_explicit_instantiation_storage_class)
10540 << FixItHint::CreateRemoval(D.getDeclSpec().getStorageClassSpecLoc());
10542 D.getMutableDeclSpec().ClearStorageClassSpecs();
10545 // C++0x [temp.explicit]p1:
10546 // [...] An explicit instantiation of a function template shall not use the
10547 // inline or constexpr specifiers.
10548 // Presumably, this also applies to member functions of class templates as
10549 // well.
10550 if (D.getDeclSpec().isInlineSpecified())
10551 Diag(D.getDeclSpec().getInlineSpecLoc(),
10552 getLangOpts().CPlusPlus11 ?
10553 diag::err_explicit_instantiation_inline :
10554 diag::warn_explicit_instantiation_inline_0x)
10555 << FixItHint::CreateRemoval(D.getDeclSpec().getInlineSpecLoc());
10556 if (D.getDeclSpec().hasConstexprSpecifier() && R->isFunctionType())
10557 // FIXME: Add a fix-it to remove the 'constexpr' and add a 'const' if one is
10558 // not already specified.
10559 Diag(D.getDeclSpec().getConstexprSpecLoc(),
10560 diag::err_explicit_instantiation_constexpr);
10562 // A deduction guide is not on the list of entities that can be explicitly
10563 // instantiated.
10564 if (Name.getNameKind() == DeclarationName::CXXDeductionGuideName) {
10565 Diag(D.getDeclSpec().getBeginLoc(), diag::err_deduction_guide_specialized)
10566 << /*explicit instantiation*/ 0;
10567 return true;
10570 // C++0x [temp.explicit]p2:
10571 // There are two forms of explicit instantiation: an explicit instantiation
10572 // definition and an explicit instantiation declaration. An explicit
10573 // instantiation declaration begins with the extern keyword. [...]
10574 TemplateSpecializationKind TSK
10575 = ExternLoc.isInvalid()? TSK_ExplicitInstantiationDefinition
10576 : TSK_ExplicitInstantiationDeclaration;
10578 LookupResult Previous(*this, NameInfo, LookupOrdinaryName);
10579 LookupParsedName(Previous, S, &D.getCXXScopeSpec());
10581 if (!R->isFunctionType()) {
10582 // C++ [temp.explicit]p1:
10583 // A [...] static data member of a class template can be explicitly
10584 // instantiated from the member definition associated with its class
10585 // template.
10586 // C++1y [temp.explicit]p1:
10587 // A [...] variable [...] template specialization can be explicitly
10588 // instantiated from its template.
10589 if (Previous.isAmbiguous())
10590 return true;
10592 VarDecl *Prev = Previous.getAsSingle<VarDecl>();
10593 VarTemplateDecl *PrevTemplate = Previous.getAsSingle<VarTemplateDecl>();
10595 if (!PrevTemplate) {
10596 if (!Prev || !Prev->isStaticDataMember()) {
10597 // We expect to see a static data member here.
10598 Diag(D.getIdentifierLoc(), diag::err_explicit_instantiation_not_known)
10599 << Name;
10600 for (LookupResult::iterator P = Previous.begin(), PEnd = Previous.end();
10601 P != PEnd; ++P)
10602 Diag((*P)->getLocation(), diag::note_explicit_instantiation_here);
10603 return true;
10606 if (!Prev->getInstantiatedFromStaticDataMember()) {
10607 // FIXME: Check for explicit specialization?
10608 Diag(D.getIdentifierLoc(),
10609 diag::err_explicit_instantiation_data_member_not_instantiated)
10610 << Prev;
10611 Diag(Prev->getLocation(), diag::note_explicit_instantiation_here);
10612 // FIXME: Can we provide a note showing where this was declared?
10613 return true;
10615 } else {
10616 // Explicitly instantiate a variable template.
10618 // C++1y [dcl.spec.auto]p6:
10619 // ... A program that uses auto or decltype(auto) in a context not
10620 // explicitly allowed in this section is ill-formed.
10622 // This includes auto-typed variable template instantiations.
10623 if (R->isUndeducedType()) {
10624 Diag(T->getTypeLoc().getBeginLoc(),
10625 diag::err_auto_not_allowed_var_inst);
10626 return true;
10629 if (D.getName().getKind() != UnqualifiedIdKind::IK_TemplateId) {
10630 // C++1y [temp.explicit]p3:
10631 // If the explicit instantiation is for a variable, the unqualified-id
10632 // in the declaration shall be a template-id.
10633 Diag(D.getIdentifierLoc(),
10634 diag::err_explicit_instantiation_without_template_id)
10635 << PrevTemplate;
10636 Diag(PrevTemplate->getLocation(),
10637 diag::note_explicit_instantiation_here);
10638 return true;
10641 // Translate the parser's template argument list into our AST format.
10642 TemplateArgumentListInfo TemplateArgs =
10643 makeTemplateArgumentListInfo(*this, *D.getName().TemplateId);
10645 DeclResult Res = CheckVarTemplateId(PrevTemplate, TemplateLoc,
10646 D.getIdentifierLoc(), TemplateArgs);
10647 if (Res.isInvalid())
10648 return true;
10650 if (!Res.isUsable()) {
10651 // We somehow specified dependent template arguments in an explicit
10652 // instantiation. This should probably only happen during error
10653 // recovery.
10654 Diag(D.getIdentifierLoc(), diag::err_explicit_instantiation_dependent);
10655 return true;
10658 // Ignore access control bits, we don't need them for redeclaration
10659 // checking.
10660 Prev = cast<VarDecl>(Res.get());
10663 // C++0x [temp.explicit]p2:
10664 // If the explicit instantiation is for a member function, a member class
10665 // or a static data member of a class template specialization, the name of
10666 // the class template specialization in the qualified-id for the member
10667 // name shall be a simple-template-id.
10669 // C++98 has the same restriction, just worded differently.
10671 // This does not apply to variable template specializations, where the
10672 // template-id is in the unqualified-id instead.
10673 if (!ScopeSpecifierHasTemplateId(D.getCXXScopeSpec()) && !PrevTemplate)
10674 Diag(D.getIdentifierLoc(),
10675 diag::ext_explicit_instantiation_without_qualified_id)
10676 << Prev << D.getCXXScopeSpec().getRange();
10678 CheckExplicitInstantiation(*this, Prev, D.getIdentifierLoc(), true, TSK);
10680 // Verify that it is okay to explicitly instantiate here.
10681 TemplateSpecializationKind PrevTSK = Prev->getTemplateSpecializationKind();
10682 SourceLocation POI = Prev->getPointOfInstantiation();
10683 bool HasNoEffect = false;
10684 if (CheckSpecializationInstantiationRedecl(D.getIdentifierLoc(), TSK, Prev,
10685 PrevTSK, POI, HasNoEffect))
10686 return true;
10688 if (!HasNoEffect) {
10689 // Instantiate static data member or variable template.
10690 Prev->setTemplateSpecializationKind(TSK, D.getIdentifierLoc());
10691 // Merge attributes.
10692 ProcessDeclAttributeList(S, Prev, D.getDeclSpec().getAttributes());
10693 if (TSK == TSK_ExplicitInstantiationDefinition)
10694 InstantiateVariableDefinition(D.getIdentifierLoc(), Prev);
10697 // Check the new variable specialization against the parsed input.
10698 if (PrevTemplate && !Context.hasSameType(Prev->getType(), R)) {
10699 Diag(T->getTypeLoc().getBeginLoc(),
10700 diag::err_invalid_var_template_spec_type)
10701 << 0 << PrevTemplate << R << Prev->getType();
10702 Diag(PrevTemplate->getLocation(), diag::note_template_declared_here)
10703 << 2 << PrevTemplate->getDeclName();
10704 return true;
10707 // FIXME: Create an ExplicitInstantiation node?
10708 return (Decl*) nullptr;
10711 // If the declarator is a template-id, translate the parser's template
10712 // argument list into our AST format.
10713 bool HasExplicitTemplateArgs = false;
10714 TemplateArgumentListInfo TemplateArgs;
10715 if (D.getName().getKind() == UnqualifiedIdKind::IK_TemplateId) {
10716 TemplateArgs = makeTemplateArgumentListInfo(*this, *D.getName().TemplateId);
10717 HasExplicitTemplateArgs = true;
10720 // C++ [temp.explicit]p1:
10721 // A [...] function [...] can be explicitly instantiated from its template.
10722 // A member function [...] of a class template can be explicitly
10723 // instantiated from the member definition associated with its class
10724 // template.
10725 UnresolvedSet<8> TemplateMatches;
10726 FunctionDecl *NonTemplateMatch = nullptr;
10727 TemplateSpecCandidateSet FailedCandidates(D.getIdentifierLoc());
10728 for (LookupResult::iterator P = Previous.begin(), PEnd = Previous.end();
10729 P != PEnd; ++P) {
10730 NamedDecl *Prev = *P;
10731 if (!HasExplicitTemplateArgs) {
10732 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Prev)) {
10733 QualType Adjusted = adjustCCAndNoReturn(R, Method->getType(),
10734 /*AdjustExceptionSpec*/true);
10735 if (Context.hasSameUnqualifiedType(Method->getType(), Adjusted)) {
10736 if (Method->getPrimaryTemplate()) {
10737 TemplateMatches.addDecl(Method, P.getAccess());
10738 } else {
10739 // FIXME: Can this assert ever happen? Needs a test.
10740 assert(!NonTemplateMatch && "Multiple NonTemplateMatches");
10741 NonTemplateMatch = Method;
10747 FunctionTemplateDecl *FunTmpl = dyn_cast<FunctionTemplateDecl>(Prev);
10748 if (!FunTmpl)
10749 continue;
10751 TemplateDeductionInfo Info(FailedCandidates.getLocation());
10752 FunctionDecl *Specialization = nullptr;
10753 if (TemplateDeductionResult TDK
10754 = DeduceTemplateArguments(FunTmpl,
10755 (HasExplicitTemplateArgs ? &TemplateArgs
10756 : nullptr),
10757 R, Specialization, Info)) {
10758 // Keep track of almost-matches.
10759 FailedCandidates.addCandidate()
10760 .set(P.getPair(), FunTmpl->getTemplatedDecl(),
10761 MakeDeductionFailureInfo(Context, TDK, Info));
10762 (void)TDK;
10763 continue;
10766 // Target attributes are part of the cuda function signature, so
10767 // the cuda target of the instantiated function must match that of its
10768 // template. Given that C++ template deduction does not take
10769 // target attributes into account, we reject candidates here that
10770 // have a different target.
10771 if (LangOpts.CUDA &&
10772 IdentifyCUDATarget(Specialization,
10773 /* IgnoreImplicitHDAttr = */ true) !=
10774 IdentifyCUDATarget(D.getDeclSpec().getAttributes())) {
10775 FailedCandidates.addCandidate().set(
10776 P.getPair(), FunTmpl->getTemplatedDecl(),
10777 MakeDeductionFailureInfo(Context, TDK_CUDATargetMismatch, Info));
10778 continue;
10781 TemplateMatches.addDecl(Specialization, P.getAccess());
10784 FunctionDecl *Specialization = NonTemplateMatch;
10785 if (!Specialization) {
10786 // Find the most specialized function template specialization.
10787 UnresolvedSetIterator Result = getMostSpecialized(
10788 TemplateMatches.begin(), TemplateMatches.end(), FailedCandidates,
10789 D.getIdentifierLoc(),
10790 PDiag(diag::err_explicit_instantiation_not_known) << Name,
10791 PDiag(diag::err_explicit_instantiation_ambiguous) << Name,
10792 PDiag(diag::note_explicit_instantiation_candidate));
10794 if (Result == TemplateMatches.end())
10795 return true;
10797 // Ignore access control bits, we don't need them for redeclaration checking.
10798 Specialization = cast<FunctionDecl>(*Result);
10801 // C++11 [except.spec]p4
10802 // In an explicit instantiation an exception-specification may be specified,
10803 // but is not required.
10804 // If an exception-specification is specified in an explicit instantiation
10805 // directive, it shall be compatible with the exception-specifications of
10806 // other declarations of that function.
10807 if (auto *FPT = R->getAs<FunctionProtoType>())
10808 if (FPT->hasExceptionSpec()) {
10809 unsigned DiagID =
10810 diag::err_mismatched_exception_spec_explicit_instantiation;
10811 if (getLangOpts().MicrosoftExt)
10812 DiagID = diag::ext_mismatched_exception_spec_explicit_instantiation;
10813 bool Result = CheckEquivalentExceptionSpec(
10814 PDiag(DiagID) << Specialization->getType(),
10815 PDiag(diag::note_explicit_instantiation_here),
10816 Specialization->getType()->getAs<FunctionProtoType>(),
10817 Specialization->getLocation(), FPT, D.getBeginLoc());
10818 // In Microsoft mode, mismatching exception specifications just cause a
10819 // warning.
10820 if (!getLangOpts().MicrosoftExt && Result)
10821 return true;
10824 if (Specialization->getTemplateSpecializationKind() == TSK_Undeclared) {
10825 Diag(D.getIdentifierLoc(),
10826 diag::err_explicit_instantiation_member_function_not_instantiated)
10827 << Specialization
10828 << (Specialization->getTemplateSpecializationKind() ==
10829 TSK_ExplicitSpecialization);
10830 Diag(Specialization->getLocation(), diag::note_explicit_instantiation_here);
10831 return true;
10834 FunctionDecl *PrevDecl = Specialization->getPreviousDecl();
10835 if (!PrevDecl && Specialization->isThisDeclarationADefinition())
10836 PrevDecl = Specialization;
10838 if (PrevDecl) {
10839 bool HasNoEffect = false;
10840 if (CheckSpecializationInstantiationRedecl(D.getIdentifierLoc(), TSK,
10841 PrevDecl,
10842 PrevDecl->getTemplateSpecializationKind(),
10843 PrevDecl->getPointOfInstantiation(),
10844 HasNoEffect))
10845 return true;
10847 // FIXME: We may still want to build some representation of this
10848 // explicit specialization.
10849 if (HasNoEffect)
10850 return (Decl*) nullptr;
10853 // HACK: libc++ has a bug where it attempts to explicitly instantiate the
10854 // functions
10855 // valarray<size_t>::valarray(size_t) and
10856 // valarray<size_t>::~valarray()
10857 // that it declared to have internal linkage with the internal_linkage
10858 // attribute. Ignore the explicit instantiation declaration in this case.
10859 if (Specialization->hasAttr<InternalLinkageAttr>() &&
10860 TSK == TSK_ExplicitInstantiationDeclaration) {
10861 if (auto *RD = dyn_cast<CXXRecordDecl>(Specialization->getDeclContext()))
10862 if (RD->getIdentifier() && RD->getIdentifier()->isStr("valarray") &&
10863 RD->isInStdNamespace())
10864 return (Decl*) nullptr;
10867 ProcessDeclAttributeList(S, Specialization, D.getDeclSpec().getAttributes());
10869 // In MSVC mode, dllimported explicit instantiation definitions are treated as
10870 // instantiation declarations.
10871 if (TSK == TSK_ExplicitInstantiationDefinition &&
10872 Specialization->hasAttr<DLLImportAttr>() &&
10873 Context.getTargetInfo().getCXXABI().isMicrosoft())
10874 TSK = TSK_ExplicitInstantiationDeclaration;
10876 Specialization->setTemplateSpecializationKind(TSK, D.getIdentifierLoc());
10878 if (Specialization->isDefined()) {
10879 // Let the ASTConsumer know that this function has been explicitly
10880 // instantiated now, and its linkage might have changed.
10881 Consumer.HandleTopLevelDecl(DeclGroupRef(Specialization));
10882 } else if (TSK == TSK_ExplicitInstantiationDefinition)
10883 InstantiateFunctionDefinition(D.getIdentifierLoc(), Specialization);
10885 // C++0x [temp.explicit]p2:
10886 // If the explicit instantiation is for a member function, a member class
10887 // or a static data member of a class template specialization, the name of
10888 // the class template specialization in the qualified-id for the member
10889 // name shall be a simple-template-id.
10891 // C++98 has the same restriction, just worded differently.
10892 FunctionTemplateDecl *FunTmpl = Specialization->getPrimaryTemplate();
10893 if (D.getName().getKind() != UnqualifiedIdKind::IK_TemplateId && !FunTmpl &&
10894 D.getCXXScopeSpec().isSet() &&
10895 !ScopeSpecifierHasTemplateId(D.getCXXScopeSpec()))
10896 Diag(D.getIdentifierLoc(),
10897 diag::ext_explicit_instantiation_without_qualified_id)
10898 << Specialization << D.getCXXScopeSpec().getRange();
10900 CheckExplicitInstantiation(
10901 *this,
10902 FunTmpl ? (NamedDecl *)FunTmpl
10903 : Specialization->getInstantiatedFromMemberFunction(),
10904 D.getIdentifierLoc(), D.getCXXScopeSpec().isSet(), TSK);
10906 // FIXME: Create some kind of ExplicitInstantiationDecl here.
10907 return (Decl*) nullptr;
10910 TypeResult
10911 Sema::ActOnDependentTag(Scope *S, unsigned TagSpec, TagUseKind TUK,
10912 const CXXScopeSpec &SS, IdentifierInfo *Name,
10913 SourceLocation TagLoc, SourceLocation NameLoc) {
10914 // This has to hold, because SS is expected to be defined.
10915 assert(Name && "Expected a name in a dependent tag");
10917 NestedNameSpecifier *NNS = SS.getScopeRep();
10918 if (!NNS)
10919 return true;
10921 TagTypeKind Kind = TypeWithKeyword::getTagTypeKindForTypeSpec(TagSpec);
10923 if (TUK == TUK_Declaration || TUK == TUK_Definition) {
10924 Diag(NameLoc, diag::err_dependent_tag_decl)
10925 << (TUK == TUK_Definition) << llvm::to_underlying(Kind)
10926 << SS.getRange();
10927 return true;
10930 // Create the resulting type.
10931 ElaboratedTypeKeyword Kwd = TypeWithKeyword::getKeywordForTagTypeKind(Kind);
10932 QualType Result = Context.getDependentNameType(Kwd, NNS, Name);
10934 // Create type-source location information for this type.
10935 TypeLocBuilder TLB;
10936 DependentNameTypeLoc TL = TLB.push<DependentNameTypeLoc>(Result);
10937 TL.setElaboratedKeywordLoc(TagLoc);
10938 TL.setQualifierLoc(SS.getWithLocInContext(Context));
10939 TL.setNameLoc(NameLoc);
10940 return CreateParsedType(Result, TLB.getTypeSourceInfo(Context, Result));
10943 TypeResult Sema::ActOnTypenameType(Scope *S, SourceLocation TypenameLoc,
10944 const CXXScopeSpec &SS,
10945 const IdentifierInfo &II,
10946 SourceLocation IdLoc,
10947 ImplicitTypenameContext IsImplicitTypename) {
10948 if (SS.isInvalid())
10949 return true;
10951 if (TypenameLoc.isValid() && S && !S->getTemplateParamParent())
10952 Diag(TypenameLoc,
10953 getLangOpts().CPlusPlus11 ?
10954 diag::warn_cxx98_compat_typename_outside_of_template :
10955 diag::ext_typename_outside_of_template)
10956 << FixItHint::CreateRemoval(TypenameLoc);
10958 NestedNameSpecifierLoc QualifierLoc = SS.getWithLocInContext(Context);
10959 TypeSourceInfo *TSI = nullptr;
10960 QualType T =
10961 CheckTypenameType((TypenameLoc.isValid() ||
10962 IsImplicitTypename == ImplicitTypenameContext::Yes)
10963 ? ElaboratedTypeKeyword::Typename
10964 : ElaboratedTypeKeyword::None,
10965 TypenameLoc, QualifierLoc, II, IdLoc, &TSI,
10966 /*DeducedTSTContext=*/true);
10967 if (T.isNull())
10968 return true;
10969 return CreateParsedType(T, TSI);
10972 TypeResult
10973 Sema::ActOnTypenameType(Scope *S,
10974 SourceLocation TypenameLoc,
10975 const CXXScopeSpec &SS,
10976 SourceLocation TemplateKWLoc,
10977 TemplateTy TemplateIn,
10978 IdentifierInfo *TemplateII,
10979 SourceLocation TemplateIILoc,
10980 SourceLocation LAngleLoc,
10981 ASTTemplateArgsPtr TemplateArgsIn,
10982 SourceLocation RAngleLoc) {
10983 if (TypenameLoc.isValid() && S && !S->getTemplateParamParent())
10984 Diag(TypenameLoc,
10985 getLangOpts().CPlusPlus11 ?
10986 diag::warn_cxx98_compat_typename_outside_of_template :
10987 diag::ext_typename_outside_of_template)
10988 << FixItHint::CreateRemoval(TypenameLoc);
10990 // Strangely, non-type results are not ignored by this lookup, so the
10991 // program is ill-formed if it finds an injected-class-name.
10992 if (TypenameLoc.isValid()) {
10993 auto *LookupRD =
10994 dyn_cast_or_null<CXXRecordDecl>(computeDeclContext(SS, false));
10995 if (LookupRD && LookupRD->getIdentifier() == TemplateII) {
10996 Diag(TemplateIILoc,
10997 diag::ext_out_of_line_qualified_id_type_names_constructor)
10998 << TemplateII << 0 /*injected-class-name used as template name*/
10999 << (TemplateKWLoc.isValid() ? 1 : 0 /*'template'/'typename' keyword*/);
11003 // Translate the parser's template argument list in our AST format.
11004 TemplateArgumentListInfo TemplateArgs(LAngleLoc, RAngleLoc);
11005 translateTemplateArguments(TemplateArgsIn, TemplateArgs);
11007 TemplateName Template = TemplateIn.get();
11008 if (DependentTemplateName *DTN = Template.getAsDependentTemplateName()) {
11009 // Construct a dependent template specialization type.
11010 assert(DTN && "dependent template has non-dependent name?");
11011 assert(DTN->getQualifier() == SS.getScopeRep());
11012 QualType T = Context.getDependentTemplateSpecializationType(
11013 ElaboratedTypeKeyword::Typename, DTN->getQualifier(),
11014 DTN->getIdentifier(), TemplateArgs.arguments());
11016 // Create source-location information for this type.
11017 TypeLocBuilder Builder;
11018 DependentTemplateSpecializationTypeLoc SpecTL
11019 = Builder.push<DependentTemplateSpecializationTypeLoc>(T);
11020 SpecTL.setElaboratedKeywordLoc(TypenameLoc);
11021 SpecTL.setQualifierLoc(SS.getWithLocInContext(Context));
11022 SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
11023 SpecTL.setTemplateNameLoc(TemplateIILoc);
11024 SpecTL.setLAngleLoc(LAngleLoc);
11025 SpecTL.setRAngleLoc(RAngleLoc);
11026 for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I)
11027 SpecTL.setArgLocInfo(I, TemplateArgs[I].getLocInfo());
11028 return CreateParsedType(T, Builder.getTypeSourceInfo(Context, T));
11031 QualType T = CheckTemplateIdType(Template, TemplateIILoc, TemplateArgs);
11032 if (T.isNull())
11033 return true;
11035 // Provide source-location information for the template specialization type.
11036 TypeLocBuilder Builder;
11037 TemplateSpecializationTypeLoc SpecTL
11038 = Builder.push<TemplateSpecializationTypeLoc>(T);
11039 SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
11040 SpecTL.setTemplateNameLoc(TemplateIILoc);
11041 SpecTL.setLAngleLoc(LAngleLoc);
11042 SpecTL.setRAngleLoc(RAngleLoc);
11043 for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I)
11044 SpecTL.setArgLocInfo(I, TemplateArgs[I].getLocInfo());
11046 T = Context.getElaboratedType(ElaboratedTypeKeyword::Typename,
11047 SS.getScopeRep(), T);
11048 ElaboratedTypeLoc TL = Builder.push<ElaboratedTypeLoc>(T);
11049 TL.setElaboratedKeywordLoc(TypenameLoc);
11050 TL.setQualifierLoc(SS.getWithLocInContext(Context));
11052 TypeSourceInfo *TSI = Builder.getTypeSourceInfo(Context, T);
11053 return CreateParsedType(T, TSI);
11057 /// Determine whether this failed name lookup should be treated as being
11058 /// disabled by a usage of std::enable_if.
11059 static bool isEnableIf(NestedNameSpecifierLoc NNS, const IdentifierInfo &II,
11060 SourceRange &CondRange, Expr *&Cond) {
11061 // We must be looking for a ::type...
11062 if (!II.isStr("type"))
11063 return false;
11065 // ... within an explicitly-written template specialization...
11066 if (!NNS || !NNS.getNestedNameSpecifier()->getAsType())
11067 return false;
11068 TypeLoc EnableIfTy = NNS.getTypeLoc();
11069 TemplateSpecializationTypeLoc EnableIfTSTLoc =
11070 EnableIfTy.getAs<TemplateSpecializationTypeLoc>();
11071 if (!EnableIfTSTLoc || EnableIfTSTLoc.getNumArgs() == 0)
11072 return false;
11073 const TemplateSpecializationType *EnableIfTST = EnableIfTSTLoc.getTypePtr();
11075 // ... which names a complete class template declaration...
11076 const TemplateDecl *EnableIfDecl =
11077 EnableIfTST->getTemplateName().getAsTemplateDecl();
11078 if (!EnableIfDecl || EnableIfTST->isIncompleteType())
11079 return false;
11081 // ... called "enable_if".
11082 const IdentifierInfo *EnableIfII =
11083 EnableIfDecl->getDeclName().getAsIdentifierInfo();
11084 if (!EnableIfII || !EnableIfII->isStr("enable_if"))
11085 return false;
11087 // Assume the first template argument is the condition.
11088 CondRange = EnableIfTSTLoc.getArgLoc(0).getSourceRange();
11090 // Dig out the condition.
11091 Cond = nullptr;
11092 if (EnableIfTSTLoc.getArgLoc(0).getArgument().getKind()
11093 != TemplateArgument::Expression)
11094 return true;
11096 Cond = EnableIfTSTLoc.getArgLoc(0).getSourceExpression();
11098 // Ignore Boolean literals; they add no value.
11099 if (isa<CXXBoolLiteralExpr>(Cond->IgnoreParenCasts()))
11100 Cond = nullptr;
11102 return true;
11105 QualType
11106 Sema::CheckTypenameType(ElaboratedTypeKeyword Keyword,
11107 SourceLocation KeywordLoc,
11108 NestedNameSpecifierLoc QualifierLoc,
11109 const IdentifierInfo &II,
11110 SourceLocation IILoc,
11111 TypeSourceInfo **TSI,
11112 bool DeducedTSTContext) {
11113 QualType T = CheckTypenameType(Keyword, KeywordLoc, QualifierLoc, II, IILoc,
11114 DeducedTSTContext);
11115 if (T.isNull())
11116 return QualType();
11118 *TSI = Context.CreateTypeSourceInfo(T);
11119 if (isa<DependentNameType>(T)) {
11120 DependentNameTypeLoc TL =
11121 (*TSI)->getTypeLoc().castAs<DependentNameTypeLoc>();
11122 TL.setElaboratedKeywordLoc(KeywordLoc);
11123 TL.setQualifierLoc(QualifierLoc);
11124 TL.setNameLoc(IILoc);
11125 } else {
11126 ElaboratedTypeLoc TL = (*TSI)->getTypeLoc().castAs<ElaboratedTypeLoc>();
11127 TL.setElaboratedKeywordLoc(KeywordLoc);
11128 TL.setQualifierLoc(QualifierLoc);
11129 TL.getNamedTypeLoc().castAs<TypeSpecTypeLoc>().setNameLoc(IILoc);
11131 return T;
11134 /// Build the type that describes a C++ typename specifier,
11135 /// e.g., "typename T::type".
11136 QualType
11137 Sema::CheckTypenameType(ElaboratedTypeKeyword Keyword,
11138 SourceLocation KeywordLoc,
11139 NestedNameSpecifierLoc QualifierLoc,
11140 const IdentifierInfo &II,
11141 SourceLocation IILoc, bool DeducedTSTContext) {
11142 CXXScopeSpec SS;
11143 SS.Adopt(QualifierLoc);
11145 DeclContext *Ctx = nullptr;
11146 if (QualifierLoc) {
11147 Ctx = computeDeclContext(SS);
11148 if (!Ctx) {
11149 // If the nested-name-specifier is dependent and couldn't be
11150 // resolved to a type, build a typename type.
11151 assert(QualifierLoc.getNestedNameSpecifier()->isDependent());
11152 return Context.getDependentNameType(Keyword,
11153 QualifierLoc.getNestedNameSpecifier(),
11154 &II);
11157 // If the nested-name-specifier refers to the current instantiation,
11158 // the "typename" keyword itself is superfluous. In C++03, the
11159 // program is actually ill-formed. However, DR 382 (in C++0x CD1)
11160 // allows such extraneous "typename" keywords, and we retroactively
11161 // apply this DR to C++03 code with only a warning. In any case we continue.
11163 if (RequireCompleteDeclContext(SS, Ctx))
11164 return QualType();
11167 DeclarationName Name(&II);
11168 LookupResult Result(*this, Name, IILoc, LookupOrdinaryName);
11169 if (Ctx)
11170 LookupQualifiedName(Result, Ctx, SS);
11171 else
11172 LookupName(Result, CurScope);
11173 unsigned DiagID = 0;
11174 Decl *Referenced = nullptr;
11175 switch (Result.getResultKind()) {
11176 case LookupResult::NotFound: {
11177 // If we're looking up 'type' within a template named 'enable_if', produce
11178 // a more specific diagnostic.
11179 SourceRange CondRange;
11180 Expr *Cond = nullptr;
11181 if (Ctx && isEnableIf(QualifierLoc, II, CondRange, Cond)) {
11182 // If we have a condition, narrow it down to the specific failed
11183 // condition.
11184 if (Cond) {
11185 Expr *FailedCond;
11186 std::string FailedDescription;
11187 std::tie(FailedCond, FailedDescription) =
11188 findFailedBooleanCondition(Cond);
11190 Diag(FailedCond->getExprLoc(),
11191 diag::err_typename_nested_not_found_requirement)
11192 << FailedDescription
11193 << FailedCond->getSourceRange();
11194 return QualType();
11197 Diag(CondRange.getBegin(),
11198 diag::err_typename_nested_not_found_enable_if)
11199 << Ctx << CondRange;
11200 return QualType();
11203 DiagID = Ctx ? diag::err_typename_nested_not_found
11204 : diag::err_unknown_typename;
11205 break;
11208 case LookupResult::FoundUnresolvedValue: {
11209 // We found a using declaration that is a value. Most likely, the using
11210 // declaration itself is meant to have the 'typename' keyword.
11211 SourceRange FullRange(KeywordLoc.isValid() ? KeywordLoc : SS.getBeginLoc(),
11212 IILoc);
11213 Diag(IILoc, diag::err_typename_refers_to_using_value_decl)
11214 << Name << Ctx << FullRange;
11215 if (UnresolvedUsingValueDecl *Using
11216 = dyn_cast<UnresolvedUsingValueDecl>(Result.getRepresentativeDecl())){
11217 SourceLocation Loc = Using->getQualifierLoc().getBeginLoc();
11218 Diag(Loc, diag::note_using_value_decl_missing_typename)
11219 << FixItHint::CreateInsertion(Loc, "typename ");
11222 // Fall through to create a dependent typename type, from which we can recover
11223 // better.
11224 [[fallthrough]];
11226 case LookupResult::NotFoundInCurrentInstantiation:
11227 // Okay, it's a member of an unknown instantiation.
11228 return Context.getDependentNameType(Keyword,
11229 QualifierLoc.getNestedNameSpecifier(),
11230 &II);
11232 case LookupResult::Found:
11233 if (TypeDecl *Type = dyn_cast<TypeDecl>(Result.getFoundDecl())) {
11234 // C++ [class.qual]p2:
11235 // In a lookup in which function names are not ignored and the
11236 // nested-name-specifier nominates a class C, if the name specified
11237 // after the nested-name-specifier, when looked up in C, is the
11238 // injected-class-name of C [...] then the name is instead considered
11239 // to name the constructor of class C.
11241 // Unlike in an elaborated-type-specifier, function names are not ignored
11242 // in typename-specifier lookup. However, they are ignored in all the
11243 // contexts where we form a typename type with no keyword (that is, in
11244 // mem-initializer-ids, base-specifiers, and elaborated-type-specifiers).
11246 // FIXME: That's not strictly true: mem-initializer-id lookup does not
11247 // ignore functions, but that appears to be an oversight.
11248 auto *LookupRD = dyn_cast_or_null<CXXRecordDecl>(Ctx);
11249 auto *FoundRD = dyn_cast<CXXRecordDecl>(Type);
11250 if (Keyword == ElaboratedTypeKeyword::Typename && LookupRD && FoundRD &&
11251 FoundRD->isInjectedClassName() &&
11252 declaresSameEntity(LookupRD, cast<Decl>(FoundRD->getParent())))
11253 Diag(IILoc, diag::ext_out_of_line_qualified_id_type_names_constructor)
11254 << &II << 1 << 0 /*'typename' keyword used*/;
11256 // We found a type. Build an ElaboratedType, since the
11257 // typename-specifier was just sugar.
11258 MarkAnyDeclReferenced(Type->getLocation(), Type, /*OdrUse=*/false);
11259 return Context.getElaboratedType(Keyword,
11260 QualifierLoc.getNestedNameSpecifier(),
11261 Context.getTypeDeclType(Type));
11264 // C++ [dcl.type.simple]p2:
11265 // A type-specifier of the form
11266 // typename[opt] nested-name-specifier[opt] template-name
11267 // is a placeholder for a deduced class type [...].
11268 if (getLangOpts().CPlusPlus17) {
11269 if (auto *TD = getAsTypeTemplateDecl(Result.getFoundDecl())) {
11270 if (!DeducedTSTContext) {
11271 QualType T(QualifierLoc
11272 ? QualifierLoc.getNestedNameSpecifier()->getAsType()
11273 : nullptr, 0);
11274 if (!T.isNull())
11275 Diag(IILoc, diag::err_dependent_deduced_tst)
11276 << (int)getTemplateNameKindForDiagnostics(TemplateName(TD)) << T;
11277 else
11278 Diag(IILoc, diag::err_deduced_tst)
11279 << (int)getTemplateNameKindForDiagnostics(TemplateName(TD));
11280 NoteTemplateLocation(*TD);
11281 return QualType();
11283 return Context.getElaboratedType(
11284 Keyword, QualifierLoc.getNestedNameSpecifier(),
11285 Context.getDeducedTemplateSpecializationType(TemplateName(TD),
11286 QualType(), false));
11290 DiagID = Ctx ? diag::err_typename_nested_not_type
11291 : diag::err_typename_not_type;
11292 Referenced = Result.getFoundDecl();
11293 break;
11295 case LookupResult::FoundOverloaded:
11296 DiagID = Ctx ? diag::err_typename_nested_not_type
11297 : diag::err_typename_not_type;
11298 Referenced = *Result.begin();
11299 break;
11301 case LookupResult::Ambiguous:
11302 return QualType();
11305 // If we get here, it's because name lookup did not find a
11306 // type. Emit an appropriate diagnostic and return an error.
11307 SourceRange FullRange(KeywordLoc.isValid() ? KeywordLoc : SS.getBeginLoc(),
11308 IILoc);
11309 if (Ctx)
11310 Diag(IILoc, DiagID) << FullRange << Name << Ctx;
11311 else
11312 Diag(IILoc, DiagID) << FullRange << Name;
11313 if (Referenced)
11314 Diag(Referenced->getLocation(),
11315 Ctx ? diag::note_typename_member_refers_here
11316 : diag::note_typename_refers_here)
11317 << Name;
11318 return QualType();
11321 namespace {
11322 // See Sema::RebuildTypeInCurrentInstantiation
11323 class CurrentInstantiationRebuilder
11324 : public TreeTransform<CurrentInstantiationRebuilder> {
11325 SourceLocation Loc;
11326 DeclarationName Entity;
11328 public:
11329 typedef TreeTransform<CurrentInstantiationRebuilder> inherited;
11331 CurrentInstantiationRebuilder(Sema &SemaRef,
11332 SourceLocation Loc,
11333 DeclarationName Entity)
11334 : TreeTransform<CurrentInstantiationRebuilder>(SemaRef),
11335 Loc(Loc), Entity(Entity) { }
11337 /// Determine whether the given type \p T has already been
11338 /// transformed.
11340 /// For the purposes of type reconstruction, a type has already been
11341 /// transformed if it is NULL or if it is not dependent.
11342 bool AlreadyTransformed(QualType T) {
11343 return T.isNull() || !T->isInstantiationDependentType();
11346 /// Returns the location of the entity whose type is being
11347 /// rebuilt.
11348 SourceLocation getBaseLocation() { return Loc; }
11350 /// Returns the name of the entity whose type is being rebuilt.
11351 DeclarationName getBaseEntity() { return Entity; }
11353 /// Sets the "base" location and entity when that
11354 /// information is known based on another transformation.
11355 void setBase(SourceLocation Loc, DeclarationName Entity) {
11356 this->Loc = Loc;
11357 this->Entity = Entity;
11360 ExprResult TransformLambdaExpr(LambdaExpr *E) {
11361 // Lambdas never need to be transformed.
11362 return E;
11365 } // end anonymous namespace
11367 /// Rebuilds a type within the context of the current instantiation.
11369 /// The type \p T is part of the type of an out-of-line member definition of
11370 /// a class template (or class template partial specialization) that was parsed
11371 /// and constructed before we entered the scope of the class template (or
11372 /// partial specialization thereof). This routine will rebuild that type now
11373 /// that we have entered the declarator's scope, which may produce different
11374 /// canonical types, e.g.,
11376 /// \code
11377 /// template<typename T>
11378 /// struct X {
11379 /// typedef T* pointer;
11380 /// pointer data();
11381 /// };
11383 /// template<typename T>
11384 /// typename X<T>::pointer X<T>::data() { ... }
11385 /// \endcode
11387 /// Here, the type "typename X<T>::pointer" will be created as a DependentNameType,
11388 /// since we do not know that we can look into X<T> when we parsed the type.
11389 /// This function will rebuild the type, performing the lookup of "pointer"
11390 /// in X<T> and returning an ElaboratedType whose canonical type is the same
11391 /// as the canonical type of T*, allowing the return types of the out-of-line
11392 /// definition and the declaration to match.
11393 TypeSourceInfo *Sema::RebuildTypeInCurrentInstantiation(TypeSourceInfo *T,
11394 SourceLocation Loc,
11395 DeclarationName Name) {
11396 if (!T || !T->getType()->isInstantiationDependentType())
11397 return T;
11399 CurrentInstantiationRebuilder Rebuilder(*this, Loc, Name);
11400 return Rebuilder.TransformType(T);
11403 ExprResult Sema::RebuildExprInCurrentInstantiation(Expr *E) {
11404 CurrentInstantiationRebuilder Rebuilder(*this, E->getExprLoc(),
11405 DeclarationName());
11406 return Rebuilder.TransformExpr(E);
11409 bool Sema::RebuildNestedNameSpecifierInCurrentInstantiation(CXXScopeSpec &SS) {
11410 if (SS.isInvalid())
11411 return true;
11413 NestedNameSpecifierLoc QualifierLoc = SS.getWithLocInContext(Context);
11414 CurrentInstantiationRebuilder Rebuilder(*this, SS.getRange().getBegin(),
11415 DeclarationName());
11416 NestedNameSpecifierLoc Rebuilt
11417 = Rebuilder.TransformNestedNameSpecifierLoc(QualifierLoc);
11418 if (!Rebuilt)
11419 return true;
11421 SS.Adopt(Rebuilt);
11422 return false;
11425 /// Rebuild the template parameters now that we know we're in a current
11426 /// instantiation.
11427 bool Sema::RebuildTemplateParamsInCurrentInstantiation(
11428 TemplateParameterList *Params) {
11429 for (unsigned I = 0, N = Params->size(); I != N; ++I) {
11430 Decl *Param = Params->getParam(I);
11432 // There is nothing to rebuild in a type parameter.
11433 if (isa<TemplateTypeParmDecl>(Param))
11434 continue;
11436 // Rebuild the template parameter list of a template template parameter.
11437 if (TemplateTemplateParmDecl *TTP
11438 = dyn_cast<TemplateTemplateParmDecl>(Param)) {
11439 if (RebuildTemplateParamsInCurrentInstantiation(
11440 TTP->getTemplateParameters()))
11441 return true;
11443 continue;
11446 // Rebuild the type of a non-type template parameter.
11447 NonTypeTemplateParmDecl *NTTP = cast<NonTypeTemplateParmDecl>(Param);
11448 TypeSourceInfo *NewTSI
11449 = RebuildTypeInCurrentInstantiation(NTTP->getTypeSourceInfo(),
11450 NTTP->getLocation(),
11451 NTTP->getDeclName());
11452 if (!NewTSI)
11453 return true;
11455 if (NewTSI->getType()->isUndeducedType()) {
11456 // C++17 [temp.dep.expr]p3:
11457 // An id-expression is type-dependent if it contains
11458 // - an identifier associated by name lookup with a non-type
11459 // template-parameter declared with a type that contains a
11460 // placeholder type (7.1.7.4),
11461 NewTSI = SubstAutoTypeSourceInfoDependent(NewTSI);
11464 if (NewTSI != NTTP->getTypeSourceInfo()) {
11465 NTTP->setTypeSourceInfo(NewTSI);
11466 NTTP->setType(NewTSI->getType());
11470 return false;
11473 /// Produces a formatted string that describes the binding of
11474 /// template parameters to template arguments.
11475 std::string
11476 Sema::getTemplateArgumentBindingsText(const TemplateParameterList *Params,
11477 const TemplateArgumentList &Args) {
11478 return getTemplateArgumentBindingsText(Params, Args.data(), Args.size());
11481 std::string
11482 Sema::getTemplateArgumentBindingsText(const TemplateParameterList *Params,
11483 const TemplateArgument *Args,
11484 unsigned NumArgs) {
11485 SmallString<128> Str;
11486 llvm::raw_svector_ostream Out(Str);
11488 if (!Params || Params->size() == 0 || NumArgs == 0)
11489 return std::string();
11491 for (unsigned I = 0, N = Params->size(); I != N; ++I) {
11492 if (I >= NumArgs)
11493 break;
11495 if (I == 0)
11496 Out << "[with ";
11497 else
11498 Out << ", ";
11500 if (const IdentifierInfo *Id = Params->getParam(I)->getIdentifier()) {
11501 Out << Id->getName();
11502 } else {
11503 Out << '$' << I;
11506 Out << " = ";
11507 Args[I].print(getPrintingPolicy(), Out,
11508 TemplateParameterList::shouldIncludeTypeForArgument(
11509 getPrintingPolicy(), Params, I));
11512 Out << ']';
11513 return std::string(Out.str());
11516 void Sema::MarkAsLateParsedTemplate(FunctionDecl *FD, Decl *FnD,
11517 CachedTokens &Toks) {
11518 if (!FD)
11519 return;
11521 auto LPT = std::make_unique<LateParsedTemplate>();
11523 // Take tokens to avoid allocations
11524 LPT->Toks.swap(Toks);
11525 LPT->D = FnD;
11526 LPT->FPO = getCurFPFeatures();
11527 LateParsedTemplateMap.insert(std::make_pair(FD, std::move(LPT)));
11529 FD->setLateTemplateParsed(true);
11532 void Sema::UnmarkAsLateParsedTemplate(FunctionDecl *FD) {
11533 if (!FD)
11534 return;
11535 FD->setLateTemplateParsed(false);
11538 bool Sema::IsInsideALocalClassWithinATemplateFunction() {
11539 DeclContext *DC = CurContext;
11541 while (DC) {
11542 if (CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(CurContext)) {
11543 const FunctionDecl *FD = RD->isLocalClass();
11544 return (FD && FD->getTemplatedKind() != FunctionDecl::TK_NonTemplate);
11545 } else if (DC->isTranslationUnit() || DC->isNamespace())
11546 return false;
11548 DC = DC->getParent();
11550 return false;
11553 namespace {
11554 /// Walk the path from which a declaration was instantiated, and check
11555 /// that every explicit specialization along that path is visible. This enforces
11556 /// C++ [temp.expl.spec]/6:
11558 /// If a template, a member template or a member of a class template is
11559 /// explicitly specialized then that specialization shall be declared before
11560 /// the first use of that specialization that would cause an implicit
11561 /// instantiation to take place, in every translation unit in which such a
11562 /// use occurs; no diagnostic is required.
11564 /// and also C++ [temp.class.spec]/1:
11566 /// A partial specialization shall be declared before the first use of a
11567 /// class template specialization that would make use of the partial
11568 /// specialization as the result of an implicit or explicit instantiation
11569 /// in every translation unit in which such a use occurs; no diagnostic is
11570 /// required.
11571 class ExplicitSpecializationVisibilityChecker {
11572 Sema &S;
11573 SourceLocation Loc;
11574 llvm::SmallVector<Module *, 8> Modules;
11575 Sema::AcceptableKind Kind;
11577 public:
11578 ExplicitSpecializationVisibilityChecker(Sema &S, SourceLocation Loc,
11579 Sema::AcceptableKind Kind)
11580 : S(S), Loc(Loc), Kind(Kind) {}
11582 void check(NamedDecl *ND) {
11583 if (auto *FD = dyn_cast<FunctionDecl>(ND))
11584 return checkImpl(FD);
11585 if (auto *RD = dyn_cast<CXXRecordDecl>(ND))
11586 return checkImpl(RD);
11587 if (auto *VD = dyn_cast<VarDecl>(ND))
11588 return checkImpl(VD);
11589 if (auto *ED = dyn_cast<EnumDecl>(ND))
11590 return checkImpl(ED);
11593 private:
11594 void diagnose(NamedDecl *D, bool IsPartialSpec) {
11595 auto Kind = IsPartialSpec ? Sema::MissingImportKind::PartialSpecialization
11596 : Sema::MissingImportKind::ExplicitSpecialization;
11597 const bool Recover = true;
11599 // If we got a custom set of modules (because only a subset of the
11600 // declarations are interesting), use them, otherwise let
11601 // diagnoseMissingImport intelligently pick some.
11602 if (Modules.empty())
11603 S.diagnoseMissingImport(Loc, D, Kind, Recover);
11604 else
11605 S.diagnoseMissingImport(Loc, D, D->getLocation(), Modules, Kind, Recover);
11608 bool CheckMemberSpecialization(const NamedDecl *D) {
11609 return Kind == Sema::AcceptableKind::Visible
11610 ? S.hasVisibleMemberSpecialization(D)
11611 : S.hasReachableMemberSpecialization(D);
11614 bool CheckExplicitSpecialization(const NamedDecl *D) {
11615 return Kind == Sema::AcceptableKind::Visible
11616 ? S.hasVisibleExplicitSpecialization(D)
11617 : S.hasReachableExplicitSpecialization(D);
11620 bool CheckDeclaration(const NamedDecl *D) {
11621 return Kind == Sema::AcceptableKind::Visible ? S.hasVisibleDeclaration(D)
11622 : S.hasReachableDeclaration(D);
11625 // Check a specific declaration. There are three problematic cases:
11627 // 1) The declaration is an explicit specialization of a template
11628 // specialization.
11629 // 2) The declaration is an explicit specialization of a member of an
11630 // templated class.
11631 // 3) The declaration is an instantiation of a template, and that template
11632 // is an explicit specialization of a member of a templated class.
11634 // We don't need to go any deeper than that, as the instantiation of the
11635 // surrounding class / etc is not triggered by whatever triggered this
11636 // instantiation, and thus should be checked elsewhere.
11637 template<typename SpecDecl>
11638 void checkImpl(SpecDecl *Spec) {
11639 bool IsHiddenExplicitSpecialization = false;
11640 if (Spec->getTemplateSpecializationKind() == TSK_ExplicitSpecialization) {
11641 IsHiddenExplicitSpecialization = Spec->getMemberSpecializationInfo()
11642 ? !CheckMemberSpecialization(Spec)
11643 : !CheckExplicitSpecialization(Spec);
11644 } else {
11645 checkInstantiated(Spec);
11648 if (IsHiddenExplicitSpecialization)
11649 diagnose(Spec->getMostRecentDecl(), false);
11652 void checkInstantiated(FunctionDecl *FD) {
11653 if (auto *TD = FD->getPrimaryTemplate())
11654 checkTemplate(TD);
11657 void checkInstantiated(CXXRecordDecl *RD) {
11658 auto *SD = dyn_cast<ClassTemplateSpecializationDecl>(RD);
11659 if (!SD)
11660 return;
11662 auto From = SD->getSpecializedTemplateOrPartial();
11663 if (auto *TD = From.dyn_cast<ClassTemplateDecl *>())
11664 checkTemplate(TD);
11665 else if (auto *TD =
11666 From.dyn_cast<ClassTemplatePartialSpecializationDecl *>()) {
11667 if (!CheckDeclaration(TD))
11668 diagnose(TD, true);
11669 checkTemplate(TD);
11673 void checkInstantiated(VarDecl *RD) {
11674 auto *SD = dyn_cast<VarTemplateSpecializationDecl>(RD);
11675 if (!SD)
11676 return;
11678 auto From = SD->getSpecializedTemplateOrPartial();
11679 if (auto *TD = From.dyn_cast<VarTemplateDecl *>())
11680 checkTemplate(TD);
11681 else if (auto *TD =
11682 From.dyn_cast<VarTemplatePartialSpecializationDecl *>()) {
11683 if (!CheckDeclaration(TD))
11684 diagnose(TD, true);
11685 checkTemplate(TD);
11689 void checkInstantiated(EnumDecl *FD) {}
11691 template<typename TemplDecl>
11692 void checkTemplate(TemplDecl *TD) {
11693 if (TD->isMemberSpecialization()) {
11694 if (!CheckMemberSpecialization(TD))
11695 diagnose(TD->getMostRecentDecl(), false);
11699 } // end anonymous namespace
11701 void Sema::checkSpecializationVisibility(SourceLocation Loc, NamedDecl *Spec) {
11702 if (!getLangOpts().Modules)
11703 return;
11705 ExplicitSpecializationVisibilityChecker(*this, Loc,
11706 Sema::AcceptableKind::Visible)
11707 .check(Spec);
11710 void Sema::checkSpecializationReachability(SourceLocation Loc,
11711 NamedDecl *Spec) {
11712 if (!getLangOpts().CPlusPlusModules)
11713 return checkSpecializationVisibility(Loc, Spec);
11715 ExplicitSpecializationVisibilityChecker(*this, Loc,
11716 Sema::AcceptableKind::Reachable)
11717 .check(Spec);
11720 /// Returns the top most location responsible for the definition of \p N.
11721 /// If \p N is a a template specialization, this is the location
11722 /// of the top of the instantiation stack.
11723 /// Otherwise, the location of \p N is returned.
11724 SourceLocation Sema::getTopMostPointOfInstantiation(const NamedDecl *N) const {
11725 if (!getLangOpts().CPlusPlus || CodeSynthesisContexts.empty())
11726 return N->getLocation();
11727 if (const auto *FD = dyn_cast<FunctionDecl>(N)) {
11728 if (!FD->isFunctionTemplateSpecialization())
11729 return FD->getLocation();
11730 } else if (!isa<ClassTemplateSpecializationDecl,
11731 VarTemplateSpecializationDecl>(N)) {
11732 return N->getLocation();
11734 for (const CodeSynthesisContext &CSC : CodeSynthesisContexts) {
11735 if (!CSC.isInstantiationRecord() || CSC.PointOfInstantiation.isInvalid())
11736 continue;
11737 return CSC.PointOfInstantiation;
11739 return N->getLocation();