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 //===----------------------------------------------------------------------===//
10
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"
42
43 #include <iterator>
44 #include <optional>
45 using namespace clang;
46 using namespace sema;
47
48 // Exported for use by Parser.
49 SourceRange
getTemplateParamsRange(TemplateParameterList const * const * Ps,unsigned N)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());
54 }
55
getTemplateDepth(Scope * S) const56 unsigned Sema::getTemplateDepth(Scope *S) const {
57 unsigned Depth = 0;
58
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;
64 }
65
66 // Note that there are template parameters with the given depth.
67 auto ParamsAtDepth = [&](unsigned D) { Depth = std::max(Depth, D + 1); };
68
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;
76 }
77 if (LSI->GLTemplateParameterList) {
78 ParamsAtDepth(LSI->GLTemplateParameterList->getDepth());
79 break;
80 }
81 }
82 }
83
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;
91 }
92 }
93
94 return Depth;
95 }
96
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.
100 ///
101 /// Note that this may return an UnresolvedUsingValueDecl if AllowDependent
102 /// is true. In all other cases it will return a TemplateDecl (or null).
getAsTemplateNameDecl(NamedDecl * D,bool AllowFunctionTemplates,bool AllowDependent)103 NamedDecl *Sema::getAsTemplateNameDecl(NamedDecl *D,
104 bool AllowFunctionTemplates,
105 bool AllowDependent) {
106 D = D->getUnderlyingDecl();
107
108 if (isa<TemplateDecl>(D)) {
109 if (!AllowFunctionTemplates && isa<FunctionTemplateDecl>(D))
110 return nullptr;
111
112 return D;
113 }
114
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();
131
132 if (const auto *Spec = dyn_cast<ClassTemplateSpecializationDecl>(Record))
133 return Spec->getSpecializedTemplate();
134 }
135
136 return nullptr;
137 }
138
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;
144
145 return nullptr;
146 }
147
FilterAcceptableTemplateNames(LookupResult & R,bool AllowFunctionTemplates,bool AllowDependent)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();
156 }
157 filter.done();
158 }
159
hasAnyAcceptableTemplateNames(LookupResult & R,bool AllowFunctionTemplates,bool AllowDependent,bool AllowNonTemplateFunctions)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;
170 }
171
172 return false;
173 }
174
isTemplateName(Scope * S,CXXScopeSpec & SS,bool hasTemplateKeyword,const UnqualifiedId & Name,ParsedType ObjectTypePtr,bool EnteringContext,TemplateTy & TemplateResult,bool & MemberOfUnknownSpecialization,bool Disambiguation)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!");
185
186 DeclarationName TName;
187 MemberOfUnknownSpecialization = false;
188
189 switch (Name.getKind()) {
190 case UnqualifiedIdKind::IK_Identifier:
191 TName = DeclarationName(Name.Identifier);
192 break;
193
194 case UnqualifiedIdKind::IK_OperatorFunctionId:
195 TName = Context.DeclarationNames.getCXXOperatorName(
196 Name.OperatorFunctionId.Operator);
197 break;
198
199 case UnqualifiedIdKind::IK_LiteralOperatorId:
200 TName = Context.DeclarationNames.getCXXLiteralOperatorName(Name.Identifier);
201 break;
202
203 default:
204 return TNK_Non_template;
205 }
206
207 QualType ObjectType = ObjectTypePtr.get();
208
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;
216
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;
225 }
226
227 if (R.empty())
228 return TNK_Non_template;
229
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;
244 }
245 }
246 }
247
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;
253 }
254
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);
259 }
260
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.
264
265 TemplateName Template;
266 TemplateNameKind TemplateKind;
267
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;
274
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");
281 }
282
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;
287 }
288
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);
297 }
298
299 if (isa<FunctionTemplateDecl>(TD)) {
300 TemplateKind = TNK_Function_template;
301
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;
312 }
313 }
314
315 TemplateResult = TemplateTy::make(Template);
316 return TemplateKind;
317 }
318
isDeductionGuideName(Scope * S,const IdentifierInfo & Name,SourceLocation NameLoc,CXXScopeSpec & SS,ParsedTemplateTy * Template)319 bool Sema::isDeductionGuideName(Scope *S, const IdentifierInfo &Name,
320 SourceLocation NameLoc, CXXScopeSpec &SS,
321 ParsedTemplateTy *Template /*=nullptr*/) {
322 bool MemberOfUnknownSpecialization = false;
323
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;
332
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;
338 }
339
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;
345
346 if (Template)
347 *Template = TemplateTy::make(TemplateName(TD));
348 return true;
349 }
350
DiagnoseUnknownTemplateName(const IdentifierInfo & II,SourceLocation IILoc,Scope * S,const CXXScopeSpec * SS,TemplateTy & SuggestedTemplate,TemplateNameKind & SuggestedKind)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;
363
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;
374 }
375
LookupTemplateName(LookupResult & Found,Scope * S,CXXScopeSpec & SS,QualType ObjectType,bool EnteringContext,bool & MemberOfUnknownSpecialization,RequiredTemplateKind RequiredTemplate,AssumedTemplateKind * ATK,bool AllowTypoCorrection)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;
386
387 if (SS.isInvalid())
388 return true;
389
390 Found.setTemplateNameLookup(true);
391
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");
406
407 // Template names cannot appear inside an Objective-C class or object type
408 // or a vector type.
409 //
410 // FIXME: This is wrong. For example:
411 //
412 // template<typename T> using Vec = T __attribute__((ext_vector_type(4)));
413 // Vec<int> vi;
414 // vi.Vec<int>::~Vec<int>();
415 //
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;
425 }
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);
431
432 // The declaration context must be complete.
433 if (LookupCtx && RequireCompleteDeclContext(SS, LookupCtx))
434 return true;
435 }
436
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);
445
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();
455 }
456
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);
469
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;
476 }
477
478 IsDependent |= Found.wasNotFoundInCurrentInstantiation();
479 }
480
481 if (Found.isAmbiguous())
482 return false;
483
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.
490 //
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());
497 });
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;
507 }
508 }
509
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);
540 }
541 }
542 }
543 }
544
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;
552 }
553
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;
565 }
566
567 return false;
568 }
569
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 [...]
576 //
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);
585
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);
613
614 // Recover by taking the template that we found in the object
615 // expression's type.
616 }
617 }
618 }
619
620 return false;
621 }
622
diagnoseExprIntendedAsTemplateName(Scope * S,ExprResult TemplateName,SourceLocation Less,SourceLocation Greater)623 void Sema::diagnoseExprIntendedAsTemplateName(Scope *S, ExprResult TemplateName,
624 SourceLocation Less,
625 SourceLocation Greater) {
626 if (TemplateName.isInvalid())
627 return;
628
629 DeclarationNameInfo NameInfo;
630 CXXScopeSpec SS;
631 LookupNameKind LookupKind;
632
633 DeclContext *LookupCtx = nullptr;
634 NamedDecl *Found = nullptr;
635 bool MissingTemplateKeyword = false;
636
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");
661 }
662
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;
669 }
670
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;
679 };
680 bool ValidateCandidate(const TypoCorrection &Candidate) override {
681 if (auto *ND = Candidate.getCorrectionDecl())
682 return S.getAsTemplateNameDecl(ND);
683 return Candidate.isKeyword();
684 }
685
686 std::unique_ptr<CorrectionCandidateCallback> clone() override {
687 return std::make_unique<TemplateCandidateFilter>(*this);
688 }
689 };
690
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);
711 }
712 if (Found)
713 Diag(Found->getLocation(),
714 diag::note_non_template_in_template_id_found);
715 return;
716 }
717 }
718
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);
723 }
724
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
ActOnDependentIdExpression(const CXXScopeSpec & SS,SourceLocation TemplateKWLoc,const DeclarationNameInfo & NameInfo,bool isAddressOfOperand,const TemplateArgumentListInfo * TemplateArgs)729 Sema::ActOnDependentIdExpression(const CXXScopeSpec &SS,
730 SourceLocation TemplateKWLoc,
731 const DeclarationNameInfo &NameInfo,
732 bool isAddressOfOperand,
733 const TemplateArgumentListInfo *TemplateArgs) {
734 DeclContext *DC = getFunctionLevelDeclContext();
735
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.
742 //
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();
749
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());
754
755 if (!MightBeCxx11UnevalField && !isAddressOfOperand && !IsEnum &&
756 isa<CXXMethodDecl>(DC) &&
757 cast<CXXMethodDecl>(DC)->isImplicitObjectMemberFunction()) {
758 QualType ThisType = cast<CXXMethodDecl>(DC)->getThisType().getNonReferenceType();
759
760 // Since the 'this' expression is synthesized, we don't need to
761 // perform the double-lookup check.
762 NamedDecl *FirstQualifierInScope = nullptr;
763
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);
769 }
770
771 return BuildDependentDeclRefExpr(SS, TemplateKWLoc, NameInfo, TemplateArgs);
772 }
773
774 ExprResult
BuildDependentDeclRefExpr(const CXXScopeSpec & SS,SourceLocation TemplateKWLoc,const DeclarationNameInfo & NameInfo,const TemplateArgumentListInfo * TemplateArgs)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();
783
784 return DependentScopeDeclRefExpr::Create(
785 Context, QualifierLoc, TemplateKWLoc, NameInfo, TemplateArgs);
786 }
787
788
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).
DiagnoseUninstantiableTemplate(SourceLocation PointOfInstantiation,NamedDecl * Instantiation,bool InstantiatedFromMember,const NamedDecl * Pattern,const NamedDecl * PatternDef,TemplateSpecializationKind TSK,bool Complain)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));
800
801 bool IsEntityBeingDefined = false;
802 if (const TagDecl *TD = dyn_cast_or_null<TagDecl>(PatternDef))
803 IsEntityBeingDefined = TD->isBeingDefined();
804
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;
816 }
817 return false;
818 }
819
820 if (!Complain || (PatternDef && PatternDef->isInvalidDecl()))
821 return true;
822
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);
847 }
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);
872 }
873 }
874
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;
882 }
883
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.
DiagnoseTemplateParameterShadow(SourceLocation Loc,Decl * PrevDecl)888 void Sema::DiagnoseTemplateParameterShadow(SourceLocation Loc, Decl *PrevDecl) {
889 assert(PrevDecl->isTemplateParameter() && "Not a template parameter");
890
891 // C++ [temp.local]p4:
892 // A template-parameter shall not be redeclared within its
893 // scope (including nested scopes).
894 //
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);
901 }
902
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.
AdjustDeclIfTemplate(Decl * & D)906 TemplateDecl *Sema::AdjustDeclIfTemplate(Decl *&D) {
907 if (TemplateDecl *Temp = dyn_cast_or_null<TemplateDecl>(D)) {
908 D = Temp->getTemplatedDecl();
909 return Temp;
910 }
911 return nullptr;
912 }
913
getTemplatePackExpansion(SourceLocation EllipsisLoc) const914 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;
923 }
924
translateTemplateArgument(Sema & SemaRef,const ParsedTemplateArgument & Arg)925 static TemplateArgumentLoc translateTemplateArgument(Sema &SemaRef,
926 const ParsedTemplateArgument &Arg) {
927
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);
935 }
936
937 case ParsedTemplateArgument::NonType: {
938 Expr *E = static_cast<Expr *>(Arg.getAsExpr());
939 return TemplateArgumentLoc(TemplateArgument(E), E);
940 }
941
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());
953 }
954 }
955
956 llvm_unreachable("Unhandled parsed template argument");
957 }
958
959 /// Translates template arguments as provided by the parser
960 /// into template arguments used by semantic analysis.
translateTemplateArguments(const ASTTemplateArgsPtr & TemplateArgsIn,TemplateArgumentListInfo & TemplateArgs)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]));
966 }
967
maybeDiagnoseTemplateParameterShadow(Sema & SemaRef,Scope * S,SourceLocation Loc,IdentifierInfo * Name)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);
975 }
976
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.
ActOnTemplateTypeArgument(TypeResult ParsedType)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");
987
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();
996 }
997
998 CXXScopeSpec SS;
999 if (auto ET = TL.getAs<ElaboratedTypeLoc>()) {
1000 SS.Adopt(ET.getQualifierLoc());
1001 TL = ET.getNamedTypeLoc();
1002 }
1003
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;
1015 }
1016 }
1017
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());
1025 }
1026
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.
ActOnTypeParameter(Scope * S,bool Typename,SourceLocation EllipsisLoc,SourceLocation KeyLoc,IdentifierInfo * ParamName,SourceLocation ParamNameLoc,unsigned Depth,unsigned Position,SourceLocation EqualLoc,ParsedType DefaultArg,bool HasTypeConstraint)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!");
1047
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);
1055
1056 if (Param->isParameterPack())
1057 if (auto *LSI = getEnclosingLambda())
1058 LSI->LocalPacks.push_back(Param);
1059
1060 if (ParamName) {
1061 maybeDiagnoseTemplateParameterShadow(*this, S, ParamNameLoc, ParamName);
1062
1063 // Add the template parameter into the current scope.
1064 S->AddDecl(Param);
1065 IdResolver.AddDecl(Param);
1066 }
1067
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;
1074 }
1075
1076 // Handle the default argument, if provided.
1077 if (DefaultArg) {
1078 TypeSourceInfo *DefaultTInfo;
1079 GetTypeFromParser(DefaultArg, &DefaultTInfo);
1080
1081 assert(DefaultTInfo && "expected source information for type");
1082
1083 // Check for unexpanded parameter packs.
1084 if (DiagnoseUnexpandedParameterPack(ParamNameLoc, DefaultTInfo,
1085 UPPC_DefaultArgument))
1086 return Param;
1087
1088 // Check the template argument itself.
1089 if (CheckTemplateArgument(DefaultTInfo)) {
1090 Param->setInvalidDecl();
1091 return Param;
1092 }
1093
1094 Param->setDefaultArgument(DefaultTInfo);
1095 }
1096
1097 return Param;
1098 }
1099
1100 /// Convert the parser's template argument list representation into our form.
1101 static TemplateArgumentListInfo
makeTemplateArgumentListInfo(Sema & S,TemplateIdAnnotation & TemplateId)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;
1109 }
1110
CheckTypeConstraint(TemplateIdAnnotation * TypeConstr)1111 bool Sema::CheckTypeConstraint(TemplateIdAnnotation *TypeConstr) {
1112
1113 TemplateName TN = TypeConstr->Template.get();
1114 ConceptDecl *CD = cast<ConceptDecl>(TN.getAsTemplateDecl());
1115
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;
1123 }
1124
1125 bool WereArgsSpecified = TypeConstr->LAngleLoc.isValid();
1126
1127 if (!WereArgsSpecified &&
1128 CD->getTemplateParameters()->getMinRequiredArguments() > 1) {
1129 Diag(TypeConstr->TemplateNameLoc,
1130 diag::err_type_constraint_missing_arguments)
1131 << CD;
1132 return true;
1133 }
1134 return false;
1135 }
1136
ActOnTypeConstraint(const CXXScopeSpec & SS,TemplateIdAnnotation * TypeConstr,TemplateTypeParmDecl * ConstrainedParameter,SourceLocation EllipsisLoc)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);
1143 }
1144
BuildTypeConstraint(const CXXScopeSpec & SS,TemplateIdAnnotation * TypeConstr,TemplateTypeParmDecl * ConstrainedParameter,SourceLocation EllipsisLoc,bool AllowUnexpandedPack)1145 bool Sema::BuildTypeConstraint(const CXXScopeSpec &SS,
1146 TemplateIdAnnotation *TypeConstr,
1147 TemplateTypeParmDecl *ConstrainedParameter,
1148 SourceLocation EllipsisLoc,
1149 bool AllowUnexpandedPack) {
1150
1151 if (CheckTypeConstraint(TypeConstr))
1152 return true;
1153
1154 TemplateName TN = TypeConstr->Template.get();
1155 ConceptDecl *CD = cast<ConceptDecl>(TN.getAsTemplateDecl());
1156
1157 DeclarationNameInfo ConceptName(DeclarationName(TypeConstr->Name),
1158 TypeConstr->TemplateNameLoc);
1159
1160 TemplateArgumentListInfo TemplateArgs;
1161 if (TypeConstr->LAngleLoc.isValid()) {
1162 TemplateArgs =
1163 makeTemplateArgumentListInfo(*this, *TypeConstr);
1164
1165 if (EllipsisLoc.isInvalid() && !AllowUnexpandedPack) {
1166 for (TemplateArgumentLoc Arg : TemplateArgs.arguments()) {
1167 if (DiagnoseUnexpandedParameterPack(Arg, UPPC_TypeConstraint))
1168 return true;
1169 }
1170 }
1171 }
1172 return AttachTypeConstraint(
1173 SS.isSet() ? SS.getWithLocInContext(Context) : NestedNameSpecifierLoc(),
1174 ConceptName, CD,
1175 TypeConstr->LAngleLoc.isValid() ? &TemplateArgs : nullptr,
1176 ConstrainedParameter, EllipsisLoc);
1177 }
1178
1179 template<typename ArgumentLocAppender>
formImmediatelyDeclaredConstraint(Sema & S,NestedNameSpecifierLoc NS,DeclarationNameInfo NameInfo,ConceptDecl * NamedConcept,SourceLocation LAngleLoc,SourceLocation RAngleLoc,QualType ConstrainedType,SourceLocation ParamNameLoc,ArgumentLocAppender Appender,SourceLocation EllipsisLoc)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) {
1186
1187 TemplateArgumentListInfo ConstraintArgs;
1188 ConstraintArgs.addArgument(
1189 S.getTrivialTemplateArgumentLoc(TemplateArgument(ConstrainedType),
1190 /*NTTPType=*/QualType(), ParamNameLoc));
1191
1192 ConstraintArgs.setRAngleLoc(RAngleLoc);
1193 ConstraintArgs.setLAngleLoc(LAngleLoc);
1194 Appender(ConstraintArgs);
1195
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;
1206
1207 // C++2a [temp.param]p4:
1208 // [...] If T is not a pack, then E is E', otherwise E is (E' && ...).
1209 //
1210 // We have the following case:
1211 //
1212 // template<typename T> concept C1 = true;
1213 // template<C1... T> struct s1;
1214 //
1215 // The constraint: (C1<T> && ...)
1216 //
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);
1225 }
1226
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).
AttachTypeConstraint(NestedNameSpecifierLoc NS,DeclarationNameInfo NameInfo,ConceptDecl * NamedConcept,const TemplateArgumentListInfo * TemplateArgs,TemplateTypeParmDecl * ConstrainedParameter,SourceLocation EllipsisLoc)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;
1243
1244 QualType ParamAsArgument(ConstrainedParameter->getTypeForDecl(), 0);
1245
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;
1259
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;
1269 }
1270
AttachTypeConstraint(AutoTypeLoc TL,NonTypeTemplateParmDecl * NewConstrainedParm,NonTypeTemplateParmDecl * OrigConstrainedParm,SourceLocation EllipsisLoc)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;
1283 }
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));
1298 },
1299 EllipsisLoc);
1300 if (ImmediatelyDeclaredConstraint.isInvalid() ||
1301 !ImmediatelyDeclaredConstraint.isUsable())
1302 return true;
1303
1304 NewConstrainedParm->setPlaceholderTypeConstraint(
1305 ImmediatelyDeclaredConstraint.get());
1306 return false;
1307 }
1308
1309 /// Check that the type of a non-type template parameter is
1310 /// well-formed.
1311 ///
1312 /// \returns the (possibly-promoted) parameter type if valid;
1313 /// otherwise, produces a diagnostic and returns a NULL type.
CheckNonTypeTemplateParameterType(TypeSourceInfo * & TSI,SourceLocation Loc)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);
1323 }
1324
1325 return CheckNonTypeTemplateParameterType(TSI->getType(), Loc);
1326 }
1327
1328 /// Require the given type to be a structural type, and diagnose if it is not.
1329 ///
1330 /// \return \c true if an error was produced.
RequireStructuralType(QualType T,SourceLocation Loc)1331 bool Sema::RequireStructuralType(QualType T, SourceLocation Loc) {
1332 if (T->isDependentType())
1333 return false;
1334
1335 if (RequireCompleteType(Loc, T, diag::err_template_nontype_parm_incomplete))
1336 return true;
1337
1338 if (T->isStructuralType())
1339 return false;
1340
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;
1345 }
1346
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;
1355 }
1356
1357 // Structural types are required to be literal types.
1358 if (RequireLiteralType(Loc, T, diag::err_template_nontype_parm_not_literal))
1359 return true;
1360
1361 Diag(Loc, diag::err_template_nontype_parm_not_structural) << T;
1362
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;
1372 }
1373 if (FD->isMutable()) {
1374 Diag(FD->getLocation(), diag::note_not_structural_mutable_field) << T;
1375 return true;
1376 }
1377 if (FD->getType()->isRValueReferenceType()) {
1378 Diag(FD->getLocation(), diag::note_not_structural_rvalue_ref_field)
1379 << T;
1380 return true;
1381 }
1382 }
1383
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;
1390 }
1391 }
1392
1393 // All subobjects are required to be of structural types.
1394 SourceLocation SubLoc;
1395 QualType SubType;
1396 int Kind = -1;
1397
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;
1405 }
1406 }
1407
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;
1416 }
1417 }
1418 }
1419
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();
1425 }
1426
1427 return true;
1428 }
1429
CheckNonTypeTemplateParameterType(QualType T,SourceLocation Loc)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();
1438 }
1439
1440 // C++ [temp.param]p4:
1441 //
1442 // A non-type template-parameter shall have one of the following
1443 // (optionally cv-qualified) types:
1444 //
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();
1460 }
1461
1462 // C++ [temp.param]p8:
1463 //
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);
1469
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();
1478
1479 // C++20 [temp.param]p6:
1480 // -- a structural type
1481 if (RequireStructuralType(T, Loc))
1482 return QualType();
1483
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();
1490 }
1491
1492 Diag(Loc, diag::warn_cxx17_compat_template_nontype_parm_type) << T;
1493 return T.getUnqualifiedType();
1494 }
1495
ActOnNonTypeTemplateParameter(Scope * S,Declarator & D,unsigned Depth,unsigned Position,SourceLocation EqualLoc,Expr * Default)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);
1502
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);
1520 };
1521 if (DS.getStorageClassSpec() != DeclSpec::SCS_unspecified)
1522 EmitDiag(DS.getStorageClassSpecLoc());
1523
1524 if (DS.getThreadStorageClassSpec() != TSCS_unspecified)
1525 EmitDiag(DS.getThreadStorageClassSpecLoc());
1526
1527 // [dcl.inline]p1:
1528 // The inline specifier can be applied only to the declaration or
1529 // definition of a variable or function.
1530
1531 if (DS.isInlineSpecified())
1532 EmitDiag(DS.getInlineSpecLoc());
1533
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.
1538
1539 if (DS.hasConstexprSpecifier())
1540 EmitDiag(DS.getConstexprSpecLoc());
1541
1542 // [dcl.fct.spec]p1:
1543 // Function-specifiers can be used only in function declarations.
1544
1545 if (DS.isVirtualSpecified())
1546 EmitDiag(DS.getVirtualSpecLoc());
1547
1548 if (DS.hasExplicitSpecifier())
1549 EmitDiag(DS.getExplicitSpecLoc());
1550
1551 if (DS.isNoreturnSpecified())
1552 EmitDiag(DS.getNoreturnSpecLoc());
1553 };
1554
1555 CheckValidDeclSpecifiers();
1556
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);
1562
1563 assert(S->isTemplateParamScope() &&
1564 "Non-type template parameter not in template parameter scope!");
1565 bool Invalid = false;
1566
1567 QualType T = CheckNonTypeTemplateParameterType(TInfo, D.getIdentifierLoc());
1568 if (T.isNull()) {
1569 T = Context.IntTy; // Recover with an 'int' type.
1570 Invalid = true;
1571 }
1572
1573 CheckFunctionOrTemplateParamDeclarator(S, D);
1574
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);
1582
1583 if (AutoTypeLoc TL = TInfo->getTypeLoc().getContainedAutoTypeLoc())
1584 if (TL.isConstrained())
1585 if (AttachTypeConstraint(TL, Param, Param, D.getEllipsisLoc()))
1586 Invalid = true;
1587
1588 if (Invalid)
1589 Param->setInvalidDecl();
1590
1591 if (Param->isParameterPack())
1592 if (auto *LSI = getEnclosingLambda())
1593 LSI->LocalPacks.push_back(Param);
1594
1595 if (ParamName) {
1596 maybeDiagnoseTemplateParameterShadow(*this, S, D.getIdentifierLoc(),
1597 ParamName);
1598
1599 // Add the template parameter into the current scope.
1600 S->AddDecl(Param);
1601 IdResolver.AddDecl(Param);
1602 }
1603
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;
1610 }
1611
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;
1617
1618 Param->setDefaultArgument(Default);
1619 }
1620
1621 return Param;
1622 }
1623
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.
ActOnTemplateTemplateParameter(Scope * S,SourceLocation TmpLoc,TemplateParameterList * Params,SourceLocation EllipsisLoc,IdentifierInfo * Name,SourceLocation NameLoc,unsigned Depth,unsigned Position,SourceLocation EqualLoc,ParsedTemplateArgument Default)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!");
1639
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);
1648
1649 if (Param->isParameterPack())
1650 if (auto *LSI = getEnclosingLambda())
1651 LSI->LocalPacks.push_back(Param);
1652
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);
1657
1658 S->AddDecl(Param);
1659 IdResolver.AddDecl(Param);
1660 }
1661
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();
1666 }
1667
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();
1674 }
1675
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.
1681 //
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;
1690 }
1691
1692 // Check for unexpanded parameter packs.
1693 if (DiagnoseUnexpandedParameterPack(DefaultArg.getLocation(),
1694 DefaultArg.getArgument().getAsTemplate(),
1695 UPPC_DefaultArgument))
1696 return Param;
1697
1698 Param->setDefaultArgument(Context, DefaultArg);
1699 }
1700
1701 return Param;
1702 }
1703
1704 namespace {
1705 class ConstraintRefersToContainingTemplateChecker
1706 : public TreeTransform<ConstraintRefersToContainingTemplateChecker> {
1707 bool Result = false;
1708 const FunctionDecl *Friend = nullptr;
1709 unsigned TemplateDepth = 0;
1710
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.
CheckIfContainingRecord(const CXXRecordDecl * CheckingRD)1713 void CheckIfContainingRecord(const CXXRecordDecl *CheckingRD) {
1714 CheckingRD = CheckingRD->getMostRecentDecl();
1715 if (!CheckingRD->isTemplated())
1716 return;
1717
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;
1723 }
1724
CheckNonTypeTemplateParmDecl(NonTypeTemplateParmDecl * D)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;
1731
1732 // Necessary because the type of the NTTP might be what refers to the parent
1733 // constriant.
1734 TransformType(D->getType());
1735 }
1736
1737 public:
1738 using inherited = TreeTransform<ConstraintRefersToContainingTemplateChecker>;
1739
ConstraintRefersToContainingTemplateChecker(Sema & SemaRef,const FunctionDecl * Friend,unsigned TemplateDepth)1740 ConstraintRefersToContainingTemplateChecker(Sema &SemaRef,
1741 const FunctionDecl *Friend,
1742 unsigned TemplateDepth)
1743 : inherited(SemaRef), Friend(Friend), TemplateDepth(TemplateDepth) {}
getResult() const1744 bool getResult() const { return Result; }
1745
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;
TransformTemplateTypeParmType(TypeLocBuilder & TLB,TemplateTypeParmTypeLoc TL,bool)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);
1761 }
1762
TransformDecl(SourceLocation Loc,Decl * D)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;
1785 }
1786 };
1787 } // namespace
1788
ConstraintExpressionDependsOnEnclosingTemplate(const FunctionDecl * Friend,unsigned TemplateDepth,const Expr * Constraint)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();
1797 }
1798
1799 /// ActOnTemplateParameterList - Builds a TemplateParameterList, optionally
1800 /// constrained by RequiresClause, that contains the template parameters in
1801 /// Params.
1802 TemplateParameterList *
ActOnTemplateParameterList(unsigned Depth,SourceLocation ExportLoc,SourceLocation TemplateLoc,SourceLocation LAngleLoc,ArrayRef<NamedDecl * > Params,SourceLocation RAngleLoc,Expr * RequiresClause)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);
1812
1813 for (NamedDecl *P : Params)
1814 warnOnReservedIdentifier(P);
1815
1816 return TemplateParameterList::Create(
1817 Context, TemplateLoc, LAngleLoc,
1818 llvm::ArrayRef(Params.data(), Params.size()), RAngleLoc, RequiresClause);
1819 }
1820
SetNestedNameSpecifier(Sema & S,TagDecl * T,const CXXScopeSpec & SS)1821 static void SetNestedNameSpecifier(Sema &S, TagDecl *T,
1822 const CXXScopeSpec &SS) {
1823 if (SS.isSet())
1824 T->setQualifierInfo(SS.getWithLocInContext(S.Context));
1825 }
1826
1827 // Returns the template parameter list with all default template argument
1828 // information.
GetTemplateParameterList(TemplateDecl * TD)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 Decl *D = TD->getMostRecentDecl();
1834 // C++11 [temp.param]p12:
1835 // A default template argument shall not be specified in a friend class
1836 // template declaration.
1837 //
1838 // Skip past friend *declarations* because they are not supposed to contain
1839 // default template arguments. Moreover, these declarations may introduce
1840 // template parameters living in different template depths than the
1841 // corresponding template parameters in TD, causing unmatched constraint
1842 // substitution.
1843 //
1844 // FIXME: Diagnose such cases within a class template:
1845 // template <class T>
1846 // struct S {
1847 // template <class = void> friend struct C;
1848 // };
1849 // template struct S<int>;
1850 while (D->getFriendObjectKind() != Decl::FriendObjectKind::FOK_None &&
1851 D->getPreviousDecl())
1852 D = D->getPreviousDecl();
1853 return cast<TemplateDecl>(D)->getTemplateParameters();
1854 }
1855
CheckClassTemplate(Scope * S,unsigned TagSpec,TagUseKind TUK,SourceLocation KWLoc,CXXScopeSpec & SS,IdentifierInfo * Name,SourceLocation NameLoc,const ParsedAttributesView & Attr,TemplateParameterList * TemplateParams,AccessSpecifier AS,SourceLocation ModulePrivateLoc,SourceLocation FriendLoc,unsigned NumOuterTemplateParamLists,TemplateParameterList ** OuterTemplateParamLists,SkipBodyInfo * SkipBody)1856 DeclResult Sema::CheckClassTemplate(
1857 Scope *S, unsigned TagSpec, TagUseKind TUK, SourceLocation KWLoc,
1858 CXXScopeSpec &SS, IdentifierInfo *Name, SourceLocation NameLoc,
1859 const ParsedAttributesView &Attr, TemplateParameterList *TemplateParams,
1860 AccessSpecifier AS, SourceLocation ModulePrivateLoc,
1861 SourceLocation FriendLoc, unsigned NumOuterTemplateParamLists,
1862 TemplateParameterList **OuterTemplateParamLists, SkipBodyInfo *SkipBody) {
1863 assert(TemplateParams && TemplateParams->size() > 0 &&
1864 "No template parameters");
1865 assert(TUK != TUK_Reference && "Can only declare or define class templates");
1866 bool Invalid = false;
1867
1868 // Check that we can declare a template here.
1869 if (CheckTemplateDeclScope(S, TemplateParams))
1870 return true;
1871
1872 TagTypeKind Kind = TypeWithKeyword::getTagTypeKindForTypeSpec(TagSpec);
1873 assert(Kind != TagTypeKind::Enum &&
1874 "can't build template of enumerated type");
1875
1876 // There is no such thing as an unnamed class template.
1877 if (!Name) {
1878 Diag(KWLoc, diag::err_template_unnamed_class);
1879 return true;
1880 }
1881
1882 // Find any previous declaration with this name. For a friend with no
1883 // scope explicitly specified, we only look for tag declarations (per
1884 // C++11 [basic.lookup.elab]p2).
1885 DeclContext *SemanticContext;
1886 LookupResult Previous(*this, Name, NameLoc,
1887 (SS.isEmpty() && TUK == TUK_Friend)
1888 ? LookupTagName : LookupOrdinaryName,
1889 forRedeclarationInCurContext());
1890 if (SS.isNotEmpty() && !SS.isInvalid()) {
1891 SemanticContext = computeDeclContext(SS, true);
1892 if (!SemanticContext) {
1893 // FIXME: Horrible, horrible hack! We can't currently represent this
1894 // in the AST, and historically we have just ignored such friend
1895 // class templates, so don't complain here.
1896 Diag(NameLoc, TUK == TUK_Friend
1897 ? diag::warn_template_qualified_friend_ignored
1898 : diag::err_template_qualified_declarator_no_match)
1899 << SS.getScopeRep() << SS.getRange();
1900 return TUK != TUK_Friend;
1901 }
1902
1903 if (RequireCompleteDeclContext(SS, SemanticContext))
1904 return true;
1905
1906 // If we're adding a template to a dependent context, we may need to
1907 // rebuilding some of the types used within the template parameter list,
1908 // now that we know what the current instantiation is.
1909 if (SemanticContext->isDependentContext()) {
1910 ContextRAII SavedContext(*this, SemanticContext);
1911 if (RebuildTemplateParamsInCurrentInstantiation(TemplateParams))
1912 Invalid = true;
1913 } else if (TUK != TUK_Friend && TUK != TUK_Reference)
1914 diagnoseQualifiedDeclaration(SS, SemanticContext, Name, NameLoc, false);
1915
1916 LookupQualifiedName(Previous, SemanticContext);
1917 } else {
1918 SemanticContext = CurContext;
1919
1920 // C++14 [class.mem]p14:
1921 // If T is the name of a class, then each of the following shall have a
1922 // name different from T:
1923 // -- every member template of class T
1924 if (TUK != TUK_Friend &&
1925 DiagnoseClassNameShadow(SemanticContext,
1926 DeclarationNameInfo(Name, NameLoc)))
1927 return true;
1928
1929 LookupName(Previous, S);
1930 }
1931
1932 if (Previous.isAmbiguous())
1933 return true;
1934
1935 NamedDecl *PrevDecl = nullptr;
1936 if (Previous.begin() != Previous.end())
1937 PrevDecl = (*Previous.begin())->getUnderlyingDecl();
1938
1939 if (PrevDecl && PrevDecl->isTemplateParameter()) {
1940 // Maybe we will complain about the shadowed template parameter.
1941 DiagnoseTemplateParameterShadow(NameLoc, PrevDecl);
1942 // Just pretend that we didn't see the previous declaration.
1943 PrevDecl = nullptr;
1944 }
1945
1946 // If there is a previous declaration with the same name, check
1947 // whether this is a valid redeclaration.
1948 ClassTemplateDecl *PrevClassTemplate =
1949 dyn_cast_or_null<ClassTemplateDecl>(PrevDecl);
1950
1951 // We may have found the injected-class-name of a class template,
1952 // class template partial specialization, or class template specialization.
1953 // In these cases, grab the template that is being defined or specialized.
1954 if (!PrevClassTemplate && PrevDecl && isa<CXXRecordDecl>(PrevDecl) &&
1955 cast<CXXRecordDecl>(PrevDecl)->isInjectedClassName()) {
1956 PrevDecl = cast<CXXRecordDecl>(PrevDecl->getDeclContext());
1957 PrevClassTemplate
1958 = cast<CXXRecordDecl>(PrevDecl)->getDescribedClassTemplate();
1959 if (!PrevClassTemplate && isa<ClassTemplateSpecializationDecl>(PrevDecl)) {
1960 PrevClassTemplate
1961 = cast<ClassTemplateSpecializationDecl>(PrevDecl)
1962 ->getSpecializedTemplate();
1963 }
1964 }
1965
1966 if (TUK == TUK_Friend) {
1967 // C++ [namespace.memdef]p3:
1968 // [...] When looking for a prior declaration of a class or a function
1969 // declared as a friend, and when the name of the friend class or
1970 // function is neither a qualified name nor a template-id, scopes outside
1971 // the innermost enclosing namespace scope are not considered.
1972 if (!SS.isSet()) {
1973 DeclContext *OutermostContext = CurContext;
1974 while (!OutermostContext->isFileContext())
1975 OutermostContext = OutermostContext->getLookupParent();
1976
1977 if (PrevDecl &&
1978 (OutermostContext->Equals(PrevDecl->getDeclContext()) ||
1979 OutermostContext->Encloses(PrevDecl->getDeclContext()))) {
1980 SemanticContext = PrevDecl->getDeclContext();
1981 } else {
1982 // Declarations in outer scopes don't matter. However, the outermost
1983 // context we computed is the semantic context for our new
1984 // declaration.
1985 PrevDecl = PrevClassTemplate = nullptr;
1986 SemanticContext = OutermostContext;
1987
1988 // Check that the chosen semantic context doesn't already contain a
1989 // declaration of this name as a non-tag type.
1990 Previous.clear(LookupOrdinaryName);
1991 DeclContext *LookupContext = SemanticContext;
1992 while (LookupContext->isTransparentContext())
1993 LookupContext = LookupContext->getLookupParent();
1994 LookupQualifiedName(Previous, LookupContext);
1995
1996 if (Previous.isAmbiguous())
1997 return true;
1998
1999 if (Previous.begin() != Previous.end())
2000 PrevDecl = (*Previous.begin())->getUnderlyingDecl();
2001 }
2002 }
2003 } else if (PrevDecl &&
2004 !isDeclInScope(Previous.getRepresentativeDecl(), SemanticContext,
2005 S, SS.isValid()))
2006 PrevDecl = PrevClassTemplate = nullptr;
2007
2008 if (auto *Shadow = dyn_cast_or_null<UsingShadowDecl>(
2009 PrevDecl ? Previous.getRepresentativeDecl() : nullptr)) {
2010 if (SS.isEmpty() &&
2011 !(PrevClassTemplate &&
2012 PrevClassTemplate->getDeclContext()->getRedeclContext()->Equals(
2013 SemanticContext->getRedeclContext()))) {
2014 Diag(KWLoc, diag::err_using_decl_conflict_reverse);
2015 Diag(Shadow->getTargetDecl()->getLocation(),
2016 diag::note_using_decl_target);
2017 Diag(Shadow->getIntroducer()->getLocation(), diag::note_using_decl) << 0;
2018 // Recover by ignoring the old declaration.
2019 PrevDecl = PrevClassTemplate = nullptr;
2020 }
2021 }
2022
2023 if (PrevClassTemplate) {
2024 // Ensure that the template parameter lists are compatible. Skip this check
2025 // for a friend in a dependent context: the template parameter list itself
2026 // could be dependent.
2027 if (!(TUK == TUK_Friend && CurContext->isDependentContext()) &&
2028 !TemplateParameterListsAreEqual(
2029 TemplateCompareNewDeclInfo(SemanticContext ? SemanticContext
2030 : CurContext,
2031 CurContext, KWLoc),
2032 TemplateParams, PrevClassTemplate,
2033 PrevClassTemplate->getTemplateParameters(), /*Complain=*/true,
2034 TPL_TemplateMatch))
2035 return true;
2036
2037 // C++ [temp.class]p4:
2038 // In a redeclaration, partial specialization, explicit
2039 // specialization or explicit instantiation of a class template,
2040 // the class-key shall agree in kind with the original class
2041 // template declaration (7.1.5.3).
2042 RecordDecl *PrevRecordDecl = PrevClassTemplate->getTemplatedDecl();
2043 if (!isAcceptableTagRedeclaration(PrevRecordDecl, Kind,
2044 TUK == TUK_Definition, KWLoc, Name)) {
2045 Diag(KWLoc, diag::err_use_with_wrong_tag)
2046 << Name
2047 << FixItHint::CreateReplacement(KWLoc, PrevRecordDecl->getKindName());
2048 Diag(PrevRecordDecl->getLocation(), diag::note_previous_use);
2049 Kind = PrevRecordDecl->getTagKind();
2050 }
2051
2052 // Check for redefinition of this class template.
2053 if (TUK == TUK_Definition) {
2054 if (TagDecl *Def = PrevRecordDecl->getDefinition()) {
2055 // If we have a prior definition that is not visible, treat this as
2056 // simply making that previous definition visible.
2057 NamedDecl *Hidden = nullptr;
2058 if (SkipBody && !hasVisibleDefinition(Def, &Hidden)) {
2059 SkipBody->ShouldSkip = true;
2060 SkipBody->Previous = Def;
2061 auto *Tmpl = cast<CXXRecordDecl>(Hidden)->getDescribedClassTemplate();
2062 assert(Tmpl && "original definition of a class template is not a "
2063 "class template?");
2064 makeMergedDefinitionVisible(Hidden);
2065 makeMergedDefinitionVisible(Tmpl);
2066 } else {
2067 Diag(NameLoc, diag::err_redefinition) << Name;
2068 Diag(Def->getLocation(), diag::note_previous_definition);
2069 // FIXME: Would it make sense to try to "forget" the previous
2070 // definition, as part of error recovery?
2071 return true;
2072 }
2073 }
2074 }
2075 } else if (PrevDecl) {
2076 // C++ [temp]p5:
2077 // A class template shall not have the same name as any other
2078 // template, class, function, object, enumeration, enumerator,
2079 // namespace, or type in the same scope (3.3), except as specified
2080 // in (14.5.4).
2081 Diag(NameLoc, diag::err_redefinition_different_kind) << Name;
2082 Diag(PrevDecl->getLocation(), diag::note_previous_definition);
2083 return true;
2084 }
2085
2086 // Check the template parameter list of this declaration, possibly
2087 // merging in the template parameter list from the previous class
2088 // template declaration. Skip this check for a friend in a dependent
2089 // context, because the template parameter list might be dependent.
2090 if (!(TUK == TUK_Friend && CurContext->isDependentContext()) &&
2091 CheckTemplateParameterList(
2092 TemplateParams,
2093 PrevClassTemplate ? GetTemplateParameterList(PrevClassTemplate)
2094 : nullptr,
2095 (SS.isSet() && SemanticContext && SemanticContext->isRecord() &&
2096 SemanticContext->isDependentContext())
2097 ? TPC_ClassTemplateMember
2098 : TUK == TUK_Friend ? TPC_FriendClassTemplate
2099 : TPC_ClassTemplate,
2100 SkipBody))
2101 Invalid = true;
2102
2103 if (SS.isSet()) {
2104 // If the name of the template was qualified, we must be defining the
2105 // template out-of-line.
2106 if (!SS.isInvalid() && !Invalid && !PrevClassTemplate) {
2107 Diag(NameLoc, TUK == TUK_Friend ? diag::err_friend_decl_does_not_match
2108 : diag::err_member_decl_does_not_match)
2109 << Name << SemanticContext << /*IsDefinition*/true << SS.getRange();
2110 Invalid = true;
2111 }
2112 }
2113
2114 // If this is a templated friend in a dependent context we should not put it
2115 // on the redecl chain. In some cases, the templated friend can be the most
2116 // recent declaration tricking the template instantiator to make substitutions
2117 // there.
2118 // FIXME: Figure out how to combine with shouldLinkDependentDeclWithPrevious
2119 bool ShouldAddRedecl
2120 = !(TUK == TUK_Friend && CurContext->isDependentContext());
2121
2122 CXXRecordDecl *NewClass =
2123 CXXRecordDecl::Create(Context, Kind, SemanticContext, KWLoc, NameLoc, Name,
2124 PrevClassTemplate && ShouldAddRedecl ?
2125 PrevClassTemplate->getTemplatedDecl() : nullptr,
2126 /*DelayTypeCreation=*/true);
2127 SetNestedNameSpecifier(*this, NewClass, SS);
2128 if (NumOuterTemplateParamLists > 0)
2129 NewClass->setTemplateParameterListsInfo(
2130 Context,
2131 llvm::ArrayRef(OuterTemplateParamLists, NumOuterTemplateParamLists));
2132
2133 // Add alignment attributes if necessary; these attributes are checked when
2134 // the ASTContext lays out the structure.
2135 if (TUK == TUK_Definition && (!SkipBody || !SkipBody->ShouldSkip)) {
2136 AddAlignmentAttributesForRecord(NewClass);
2137 AddMsStructLayoutForRecord(NewClass);
2138 }
2139
2140 ClassTemplateDecl *NewTemplate
2141 = ClassTemplateDecl::Create(Context, SemanticContext, NameLoc,
2142 DeclarationName(Name), TemplateParams,
2143 NewClass);
2144
2145 if (ShouldAddRedecl)
2146 NewTemplate->setPreviousDecl(PrevClassTemplate);
2147
2148 NewClass->setDescribedClassTemplate(NewTemplate);
2149
2150 if (ModulePrivateLoc.isValid())
2151 NewTemplate->setModulePrivate();
2152
2153 // Build the type for the class template declaration now.
2154 QualType T = NewTemplate->getInjectedClassNameSpecialization();
2155 T = Context.getInjectedClassNameType(NewClass, T);
2156 assert(T->isDependentType() && "Class template type is not dependent?");
2157 (void)T;
2158
2159 // If we are providing an explicit specialization of a member that is a
2160 // class template, make a note of that.
2161 if (PrevClassTemplate &&
2162 PrevClassTemplate->getInstantiatedFromMemberTemplate())
2163 PrevClassTemplate->setMemberSpecialization();
2164
2165 // Set the access specifier.
2166 if (!Invalid && TUK != TUK_Friend && NewTemplate->getDeclContext()->isRecord())
2167 SetMemberAccessSpecifier(NewTemplate, PrevClassTemplate, AS);
2168
2169 // Set the lexical context of these templates
2170 NewClass->setLexicalDeclContext(CurContext);
2171 NewTemplate->setLexicalDeclContext(CurContext);
2172
2173 if (TUK == TUK_Definition && (!SkipBody || !SkipBody->ShouldSkip))
2174 NewClass->startDefinition();
2175
2176 ProcessDeclAttributeList(S, NewClass, Attr);
2177
2178 if (PrevClassTemplate)
2179 mergeDeclAttributes(NewClass, PrevClassTemplate->getTemplatedDecl());
2180
2181 AddPushedVisibilityAttribute(NewClass);
2182 inferGslOwnerPointerAttribute(NewClass);
2183
2184 if (TUK != TUK_Friend) {
2185 // Per C++ [basic.scope.temp]p2, skip the template parameter scopes.
2186 Scope *Outer = S;
2187 while ((Outer->getFlags() & Scope::TemplateParamScope) != 0)
2188 Outer = Outer->getParent();
2189 PushOnScopeChains(NewTemplate, Outer);
2190 } else {
2191 if (PrevClassTemplate && PrevClassTemplate->getAccess() != AS_none) {
2192 NewTemplate->setAccess(PrevClassTemplate->getAccess());
2193 NewClass->setAccess(PrevClassTemplate->getAccess());
2194 }
2195
2196 NewTemplate->setObjectOfFriendDecl();
2197
2198 // Friend templates are visible in fairly strange ways.
2199 if (!CurContext->isDependentContext()) {
2200 DeclContext *DC = SemanticContext->getRedeclContext();
2201 DC->makeDeclVisibleInContext(NewTemplate);
2202 if (Scope *EnclosingScope = getScopeForDeclContext(S, DC))
2203 PushOnScopeChains(NewTemplate, EnclosingScope,
2204 /* AddToContext = */ false);
2205 }
2206
2207 FriendDecl *Friend = FriendDecl::Create(
2208 Context, CurContext, NewClass->getLocation(), NewTemplate, FriendLoc);
2209 Friend->setAccess(AS_public);
2210 CurContext->addDecl(Friend);
2211 }
2212
2213 if (PrevClassTemplate)
2214 CheckRedeclarationInModule(NewTemplate, PrevClassTemplate);
2215
2216 if (Invalid) {
2217 NewTemplate->setInvalidDecl();
2218 NewClass->setInvalidDecl();
2219 }
2220
2221 ActOnDocumentableDecl(NewTemplate);
2222
2223 if (SkipBody && SkipBody->ShouldSkip)
2224 return SkipBody->Previous;
2225
2226 return NewTemplate;
2227 }
2228
2229 namespace {
2230 /// Tree transform to "extract" a transformed type from a class template's
2231 /// constructor to a deduction guide.
2232 class ExtractTypeForDeductionGuide
2233 : public TreeTransform<ExtractTypeForDeductionGuide> {
2234 llvm::SmallVectorImpl<TypedefNameDecl *> &MaterializedTypedefs;
2235
2236 public:
2237 typedef TreeTransform<ExtractTypeForDeductionGuide> Base;
ExtractTypeForDeductionGuide(Sema & SemaRef,llvm::SmallVectorImpl<TypedefNameDecl * > & MaterializedTypedefs)2238 ExtractTypeForDeductionGuide(
2239 Sema &SemaRef,
2240 llvm::SmallVectorImpl<TypedefNameDecl *> &MaterializedTypedefs)
2241 : Base(SemaRef), MaterializedTypedefs(MaterializedTypedefs) {}
2242
transform(TypeSourceInfo * TSI)2243 TypeSourceInfo *transform(TypeSourceInfo *TSI) { return TransformType(TSI); }
2244
TransformTypedefType(TypeLocBuilder & TLB,TypedefTypeLoc TL)2245 QualType TransformTypedefType(TypeLocBuilder &TLB, TypedefTypeLoc TL) {
2246 ASTContext &Context = SemaRef.getASTContext();
2247 TypedefNameDecl *OrigDecl = TL.getTypedefNameDecl();
2248 TypedefNameDecl *Decl = OrigDecl;
2249 // Transform the underlying type of the typedef and clone the Decl only if
2250 // the typedef has a dependent context.
2251 if (OrigDecl->getDeclContext()->isDependentContext()) {
2252 TypeLocBuilder InnerTLB;
2253 QualType Transformed =
2254 TransformType(InnerTLB, OrigDecl->getTypeSourceInfo()->getTypeLoc());
2255 TypeSourceInfo *TSI = InnerTLB.getTypeSourceInfo(Context, Transformed);
2256 if (isa<TypeAliasDecl>(OrigDecl))
2257 Decl = TypeAliasDecl::Create(
2258 Context, Context.getTranslationUnitDecl(), OrigDecl->getBeginLoc(),
2259 OrigDecl->getLocation(), OrigDecl->getIdentifier(), TSI);
2260 else {
2261 assert(isa<TypedefDecl>(OrigDecl) && "Not a Type alias or typedef");
2262 Decl = TypedefDecl::Create(
2263 Context, Context.getTranslationUnitDecl(), OrigDecl->getBeginLoc(),
2264 OrigDecl->getLocation(), OrigDecl->getIdentifier(), TSI);
2265 }
2266 MaterializedTypedefs.push_back(Decl);
2267 }
2268
2269 QualType TDTy = Context.getTypedefType(Decl);
2270 TypedefTypeLoc TypedefTL = TLB.push<TypedefTypeLoc>(TDTy);
2271 TypedefTL.setNameLoc(TL.getNameLoc());
2272
2273 return TDTy;
2274 }
2275 };
2276
2277 /// Transform to convert portions of a constructor declaration into the
2278 /// corresponding deduction guide, per C++1z [over.match.class.deduct]p1.
2279 struct ConvertConstructorToDeductionGuideTransform {
ConvertConstructorToDeductionGuideTransform__anonb04a1dd90811::ConvertConstructorToDeductionGuideTransform2280 ConvertConstructorToDeductionGuideTransform(Sema &S,
2281 ClassTemplateDecl *Template)
2282 : SemaRef(S), Template(Template) {
2283 // If the template is nested, then we need to use the original
2284 // pattern to iterate over the constructors.
2285 ClassTemplateDecl *Pattern = Template;
2286 while (Pattern->getInstantiatedFromMemberTemplate()) {
2287 if (Pattern->isMemberSpecialization())
2288 break;
2289 Pattern = Pattern->getInstantiatedFromMemberTemplate();
2290 NestedPattern = Pattern;
2291 }
2292
2293 if (NestedPattern)
2294 OuterInstantiationArgs = SemaRef.getTemplateInstantiationArgs(Template);
2295 }
2296
2297 Sema &SemaRef;
2298 ClassTemplateDecl *Template;
2299 ClassTemplateDecl *NestedPattern = nullptr;
2300
2301 DeclContext *DC = Template->getDeclContext();
2302 CXXRecordDecl *Primary = Template->getTemplatedDecl();
2303 DeclarationName DeductionGuideName =
2304 SemaRef.Context.DeclarationNames.getCXXDeductionGuideName(Template);
2305
2306 QualType DeducedType = SemaRef.Context.getTypeDeclType(Primary);
2307
2308 // Index adjustment to apply to convert depth-1 template parameters into
2309 // depth-0 template parameters.
2310 unsigned Depth1IndexAdjustment = Template->getTemplateParameters()->size();
2311
2312 // Instantiation arguments for the outermost depth-1 templates
2313 // when the template is nested
2314 MultiLevelTemplateArgumentList OuterInstantiationArgs;
2315
2316 /// Transform a constructor declaration into a deduction guide.
transformConstructor__anonb04a1dd90811::ConvertConstructorToDeductionGuideTransform2317 NamedDecl *transformConstructor(FunctionTemplateDecl *FTD,
2318 CXXConstructorDecl *CD) {
2319 SmallVector<TemplateArgument, 16> SubstArgs;
2320
2321 LocalInstantiationScope Scope(SemaRef);
2322
2323 // C++ [over.match.class.deduct]p1:
2324 // -- For each constructor of the class template designated by the
2325 // template-name, a function template with the following properties:
2326
2327 // -- The template parameters are the template parameters of the class
2328 // template followed by the template parameters (including default
2329 // template arguments) of the constructor, if any.
2330 TemplateParameterList *TemplateParams = GetTemplateParameterList(Template);
2331 if (FTD) {
2332 TemplateParameterList *InnerParams = FTD->getTemplateParameters();
2333 SmallVector<NamedDecl *, 16> AllParams;
2334 SmallVector<TemplateArgument, 16> Depth1Args;
2335 AllParams.reserve(TemplateParams->size() + InnerParams->size());
2336 AllParams.insert(AllParams.begin(),
2337 TemplateParams->begin(), TemplateParams->end());
2338 SubstArgs.reserve(InnerParams->size());
2339 Depth1Args.reserve(InnerParams->size());
2340
2341 // Later template parameters could refer to earlier ones, so build up
2342 // a list of substituted template arguments as we go.
2343 for (NamedDecl *Param : *InnerParams) {
2344 MultiLevelTemplateArgumentList Args;
2345 Args.setKind(TemplateSubstitutionKind::Rewrite);
2346 Args.addOuterTemplateArguments(Depth1Args);
2347 Args.addOuterRetainedLevel();
2348 if (NestedPattern)
2349 Args.addOuterRetainedLevels(NestedPattern->getTemplateDepth());
2350 NamedDecl *NewParam = transformTemplateParameter(Param, Args);
2351 if (!NewParam)
2352 return nullptr;
2353
2354 // Constraints require that we substitute depth-1 arguments
2355 // to match depths when substituted for evaluation later
2356 Depth1Args.push_back(SemaRef.Context.getCanonicalTemplateArgument(
2357 SemaRef.Context.getInjectedTemplateArg(NewParam)));
2358
2359 if (NestedPattern) {
2360 TemplateDeclInstantiator Instantiator(SemaRef, DC,
2361 OuterInstantiationArgs);
2362 Instantiator.setEvaluateConstraints(false);
2363 SemaRef.runWithSufficientStackSpace(NewParam->getLocation(), [&] {
2364 NewParam = cast<NamedDecl>(Instantiator.Visit(NewParam));
2365 });
2366 }
2367
2368 assert(NewParam->getTemplateDepth() == 0 &&
2369 "Unexpected template parameter depth");
2370
2371 AllParams.push_back(NewParam);
2372 SubstArgs.push_back(SemaRef.Context.getCanonicalTemplateArgument(
2373 SemaRef.Context.getInjectedTemplateArg(NewParam)));
2374 }
2375
2376 // Substitute new template parameters into requires-clause if present.
2377 Expr *RequiresClause = nullptr;
2378 if (Expr *InnerRC = InnerParams->getRequiresClause()) {
2379 MultiLevelTemplateArgumentList Args;
2380 Args.setKind(TemplateSubstitutionKind::Rewrite);
2381 Args.addOuterTemplateArguments(Depth1Args);
2382 Args.addOuterRetainedLevel();
2383 if (NestedPattern)
2384 Args.addOuterRetainedLevels(NestedPattern->getTemplateDepth());
2385 ExprResult E = SemaRef.SubstExpr(InnerRC, Args);
2386 if (E.isInvalid())
2387 return nullptr;
2388 RequiresClause = E.getAs<Expr>();
2389 }
2390
2391 TemplateParams = TemplateParameterList::Create(
2392 SemaRef.Context, InnerParams->getTemplateLoc(),
2393 InnerParams->getLAngleLoc(), AllParams, InnerParams->getRAngleLoc(),
2394 RequiresClause);
2395 }
2396
2397 // If we built a new template-parameter-list, track that we need to
2398 // substitute references to the old parameters into references to the
2399 // new ones.
2400 MultiLevelTemplateArgumentList Args;
2401 Args.setKind(TemplateSubstitutionKind::Rewrite);
2402 if (FTD) {
2403 Args.addOuterTemplateArguments(SubstArgs);
2404 Args.addOuterRetainedLevel();
2405 }
2406
2407 FunctionProtoTypeLoc FPTL = CD->getTypeSourceInfo()->getTypeLoc()
2408 .getAsAdjusted<FunctionProtoTypeLoc>();
2409 assert(FPTL && "no prototype for constructor declaration");
2410
2411 // Transform the type of the function, adjusting the return type and
2412 // replacing references to the old parameters with references to the
2413 // new ones.
2414 TypeLocBuilder TLB;
2415 SmallVector<ParmVarDecl*, 8> Params;
2416 SmallVector<TypedefNameDecl *, 4> MaterializedTypedefs;
2417 QualType NewType = transformFunctionProtoType(TLB, FPTL, Params, Args,
2418 MaterializedTypedefs);
2419 if (NewType.isNull())
2420 return nullptr;
2421 TypeSourceInfo *NewTInfo = TLB.getTypeSourceInfo(SemaRef.Context, NewType);
2422
2423 return buildDeductionGuide(TemplateParams, CD, CD->getExplicitSpecifier(),
2424 NewTInfo, CD->getBeginLoc(), CD->getLocation(),
2425 CD->getEndLoc(), MaterializedTypedefs);
2426 }
2427
2428 /// Build a deduction guide with the specified parameter types.
buildSimpleDeductionGuide__anonb04a1dd90811::ConvertConstructorToDeductionGuideTransform2429 NamedDecl *buildSimpleDeductionGuide(MutableArrayRef<QualType> ParamTypes) {
2430 SourceLocation Loc = Template->getLocation();
2431
2432 // Build the requested type.
2433 FunctionProtoType::ExtProtoInfo EPI;
2434 EPI.HasTrailingReturn = true;
2435 QualType Result = SemaRef.BuildFunctionType(DeducedType, ParamTypes, Loc,
2436 DeductionGuideName, EPI);
2437 TypeSourceInfo *TSI = SemaRef.Context.getTrivialTypeSourceInfo(Result, Loc);
2438 if (NestedPattern)
2439 TSI = SemaRef.SubstType(TSI, OuterInstantiationArgs, Loc,
2440 DeductionGuideName);
2441
2442 FunctionProtoTypeLoc FPTL =
2443 TSI->getTypeLoc().castAs<FunctionProtoTypeLoc>();
2444
2445 // Build the parameters, needed during deduction / substitution.
2446 SmallVector<ParmVarDecl*, 4> Params;
2447 for (auto T : ParamTypes) {
2448 auto *TSI = SemaRef.Context.getTrivialTypeSourceInfo(T, Loc);
2449 if (NestedPattern)
2450 TSI = SemaRef.SubstType(TSI, OuterInstantiationArgs, Loc,
2451 DeclarationName());
2452 ParmVarDecl *NewParam =
2453 ParmVarDecl::Create(SemaRef.Context, DC, Loc, Loc, nullptr,
2454 TSI->getType(), TSI, SC_None, nullptr);
2455 NewParam->setScopeInfo(0, Params.size());
2456 FPTL.setParam(Params.size(), NewParam);
2457 Params.push_back(NewParam);
2458 }
2459
2460 return buildDeductionGuide(GetTemplateParameterList(Template), nullptr,
2461 ExplicitSpecifier(), TSI, Loc, Loc, Loc);
2462 }
2463
2464 private:
2465 /// Transform a constructor template parameter into a deduction guide template
2466 /// parameter, rebuilding any internal references to earlier parameters and
2467 /// renumbering as we go.
transformTemplateParameter__anonb04a1dd90811::ConvertConstructorToDeductionGuideTransform2468 NamedDecl *transformTemplateParameter(NamedDecl *TemplateParam,
2469 MultiLevelTemplateArgumentList &Args) {
2470 if (auto *TTP = dyn_cast<TemplateTypeParmDecl>(TemplateParam)) {
2471 // TemplateTypeParmDecl's index cannot be changed after creation, so
2472 // substitute it directly.
2473 auto *NewTTP = TemplateTypeParmDecl::Create(
2474 SemaRef.Context, DC, TTP->getBeginLoc(), TTP->getLocation(),
2475 TTP->getDepth() - 1, Depth1IndexAdjustment + TTP->getIndex(),
2476 TTP->getIdentifier(), TTP->wasDeclaredWithTypename(),
2477 TTP->isParameterPack(), TTP->hasTypeConstraint(),
2478 TTP->isExpandedParameterPack()
2479 ? std::optional<unsigned>(TTP->getNumExpansionParameters())
2480 : std::nullopt);
2481 if (const auto *TC = TTP->getTypeConstraint())
2482 SemaRef.SubstTypeConstraint(NewTTP, TC, Args,
2483 /*EvaluateConstraint*/ true);
2484 if (TTP->hasDefaultArgument()) {
2485 TypeSourceInfo *InstantiatedDefaultArg =
2486 SemaRef.SubstType(TTP->getDefaultArgumentInfo(), Args,
2487 TTP->getDefaultArgumentLoc(), TTP->getDeclName());
2488 if (InstantiatedDefaultArg)
2489 NewTTP->setDefaultArgument(InstantiatedDefaultArg);
2490 }
2491 SemaRef.CurrentInstantiationScope->InstantiatedLocal(TemplateParam,
2492 NewTTP);
2493 return NewTTP;
2494 }
2495
2496 if (auto *TTP = dyn_cast<TemplateTemplateParmDecl>(TemplateParam))
2497 return transformTemplateParameterImpl(TTP, Args);
2498
2499 return transformTemplateParameterImpl(
2500 cast<NonTypeTemplateParmDecl>(TemplateParam), Args);
2501 }
2502 template<typename TemplateParmDecl>
2503 TemplateParmDecl *
transformTemplateParameterImpl__anonb04a1dd90811::ConvertConstructorToDeductionGuideTransform2504 transformTemplateParameterImpl(TemplateParmDecl *OldParam,
2505 MultiLevelTemplateArgumentList &Args) {
2506 // Ask the template instantiator to do the heavy lifting for us, then adjust
2507 // the index of the parameter once it's done.
2508 auto *NewParam =
2509 cast<TemplateParmDecl>(SemaRef.SubstDecl(OldParam, DC, Args));
2510 assert(NewParam->getDepth() == OldParam->getDepth() - 1 &&
2511 "unexpected template param depth");
2512 NewParam->setPosition(NewParam->getPosition() + Depth1IndexAdjustment);
2513 return NewParam;
2514 }
2515
transformFunctionProtoType__anonb04a1dd90811::ConvertConstructorToDeductionGuideTransform2516 QualType transformFunctionProtoType(
2517 TypeLocBuilder &TLB, FunctionProtoTypeLoc TL,
2518 SmallVectorImpl<ParmVarDecl *> &Params,
2519 MultiLevelTemplateArgumentList &Args,
2520 SmallVectorImpl<TypedefNameDecl *> &MaterializedTypedefs) {
2521 SmallVector<QualType, 4> ParamTypes;
2522 const FunctionProtoType *T = TL.getTypePtr();
2523
2524 // -- The types of the function parameters are those of the constructor.
2525 for (auto *OldParam : TL.getParams()) {
2526 ParmVarDecl *NewParam = OldParam;
2527 // Given
2528 // template <class T> struct C {
2529 // template <class U> struct D {
2530 // template <class V> D(U, V);
2531 // };
2532 // };
2533 // First, transform all the references to template parameters that are
2534 // defined outside of the surrounding class template. That is T in the
2535 // above example.
2536 if (NestedPattern) {
2537 NewParam = transformFunctionTypeParam(NewParam, OuterInstantiationArgs,
2538 MaterializedTypedefs);
2539 if (!NewParam)
2540 return QualType();
2541 }
2542 // Then, transform all the references to template parameters that are
2543 // defined at the class template and the constructor. In this example,
2544 // they're U and V, respectively.
2545 NewParam =
2546 transformFunctionTypeParam(NewParam, Args, MaterializedTypedefs);
2547 if (!NewParam)
2548 return QualType();
2549 ParamTypes.push_back(NewParam->getType());
2550 Params.push_back(NewParam);
2551 }
2552
2553 // -- The return type is the class template specialization designated by
2554 // the template-name and template arguments corresponding to the
2555 // template parameters obtained from the class template.
2556 //
2557 // We use the injected-class-name type of the primary template instead.
2558 // This has the convenient property that it is different from any type that
2559 // the user can write in a deduction-guide (because they cannot enter the
2560 // context of the template), so implicit deduction guides can never collide
2561 // with explicit ones.
2562 QualType ReturnType = DeducedType;
2563 TLB.pushTypeSpec(ReturnType).setNameLoc(Primary->getLocation());
2564
2565 // Resolving a wording defect, we also inherit the variadicness of the
2566 // constructor.
2567 FunctionProtoType::ExtProtoInfo EPI;
2568 EPI.Variadic = T->isVariadic();
2569 EPI.HasTrailingReturn = true;
2570
2571 QualType Result = SemaRef.BuildFunctionType(
2572 ReturnType, ParamTypes, TL.getBeginLoc(), DeductionGuideName, EPI);
2573 if (Result.isNull())
2574 return QualType();
2575
2576 FunctionProtoTypeLoc NewTL = TLB.push<FunctionProtoTypeLoc>(Result);
2577 NewTL.setLocalRangeBegin(TL.getLocalRangeBegin());
2578 NewTL.setLParenLoc(TL.getLParenLoc());
2579 NewTL.setRParenLoc(TL.getRParenLoc());
2580 NewTL.setExceptionSpecRange(SourceRange());
2581 NewTL.setLocalRangeEnd(TL.getLocalRangeEnd());
2582 for (unsigned I = 0, E = NewTL.getNumParams(); I != E; ++I)
2583 NewTL.setParam(I, Params[I]);
2584
2585 return Result;
2586 }
2587
transformFunctionTypeParam__anonb04a1dd90811::ConvertConstructorToDeductionGuideTransform2588 ParmVarDecl *transformFunctionTypeParam(
2589 ParmVarDecl *OldParam, MultiLevelTemplateArgumentList &Args,
2590 llvm::SmallVectorImpl<TypedefNameDecl *> &MaterializedTypedefs) {
2591 TypeSourceInfo *OldDI = OldParam->getTypeSourceInfo();
2592 TypeSourceInfo *NewDI;
2593 if (auto PackTL = OldDI->getTypeLoc().getAs<PackExpansionTypeLoc>()) {
2594 // Expand out the one and only element in each inner pack.
2595 Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, 0);
2596 NewDI =
2597 SemaRef.SubstType(PackTL.getPatternLoc(), Args,
2598 OldParam->getLocation(), OldParam->getDeclName());
2599 if (!NewDI) return nullptr;
2600 NewDI =
2601 SemaRef.CheckPackExpansion(NewDI, PackTL.getEllipsisLoc(),
2602 PackTL.getTypePtr()->getNumExpansions());
2603 } else
2604 NewDI = SemaRef.SubstType(OldDI, Args, OldParam->getLocation(),
2605 OldParam->getDeclName());
2606 if (!NewDI)
2607 return nullptr;
2608
2609 // Extract the type. This (for instance) replaces references to typedef
2610 // members of the current instantiations with the definitions of those
2611 // typedefs, avoiding triggering instantiation of the deduced type during
2612 // deduction.
2613 NewDI = ExtractTypeForDeductionGuide(SemaRef, MaterializedTypedefs)
2614 .transform(NewDI);
2615
2616 // Resolving a wording defect, we also inherit default arguments from the
2617 // constructor.
2618 ExprResult NewDefArg;
2619 if (OldParam->hasDefaultArg()) {
2620 // We don't care what the value is (we won't use it); just create a
2621 // placeholder to indicate there is a default argument.
2622 QualType ParamTy = NewDI->getType();
2623 NewDefArg = new (SemaRef.Context)
2624 OpaqueValueExpr(OldParam->getDefaultArg()->getBeginLoc(),
2625 ParamTy.getNonLValueExprType(SemaRef.Context),
2626 ParamTy->isLValueReferenceType() ? VK_LValue
2627 : ParamTy->isRValueReferenceType() ? VK_XValue
2628 : VK_PRValue);
2629 }
2630 // Handle arrays and functions decay.
2631 auto NewType = NewDI->getType();
2632 if (NewType->isArrayType() || NewType->isFunctionType())
2633 NewType = SemaRef.Context.getDecayedType(NewType);
2634
2635 ParmVarDecl *NewParam = ParmVarDecl::Create(
2636 SemaRef.Context, DC, OldParam->getInnerLocStart(),
2637 OldParam->getLocation(), OldParam->getIdentifier(), NewType, NewDI,
2638 OldParam->getStorageClass(), NewDefArg.get());
2639 NewParam->setScopeInfo(OldParam->getFunctionScopeDepth(),
2640 OldParam->getFunctionScopeIndex());
2641 SemaRef.CurrentInstantiationScope->InstantiatedLocal(OldParam, NewParam);
2642 return NewParam;
2643 }
2644
buildDeductionGuide__anonb04a1dd90811::ConvertConstructorToDeductionGuideTransform2645 FunctionTemplateDecl *buildDeductionGuide(
2646 TemplateParameterList *TemplateParams, CXXConstructorDecl *Ctor,
2647 ExplicitSpecifier ES, TypeSourceInfo *TInfo, SourceLocation LocStart,
2648 SourceLocation Loc, SourceLocation LocEnd,
2649 llvm::ArrayRef<TypedefNameDecl *> MaterializedTypedefs = {}) {
2650 DeclarationNameInfo Name(DeductionGuideName, Loc);
2651 ArrayRef<ParmVarDecl *> Params =
2652 TInfo->getTypeLoc().castAs<FunctionProtoTypeLoc>().getParams();
2653
2654 // Build the implicit deduction guide template.
2655 auto *Guide =
2656 CXXDeductionGuideDecl::Create(SemaRef.Context, DC, LocStart, ES, Name,
2657 TInfo->getType(), TInfo, LocEnd, Ctor);
2658 Guide->setImplicit();
2659 Guide->setParams(Params);
2660
2661 for (auto *Param : Params)
2662 Param->setDeclContext(Guide);
2663 for (auto *TD : MaterializedTypedefs)
2664 TD->setDeclContext(Guide);
2665
2666 auto *GuideTemplate = FunctionTemplateDecl::Create(
2667 SemaRef.Context, DC, Loc, DeductionGuideName, TemplateParams, Guide);
2668 GuideTemplate->setImplicit();
2669 Guide->setDescribedFunctionTemplate(GuideTemplate);
2670
2671 if (isa<CXXRecordDecl>(DC)) {
2672 Guide->setAccess(AS_public);
2673 GuideTemplate->setAccess(AS_public);
2674 }
2675
2676 DC->addDecl(GuideTemplate);
2677 return GuideTemplate;
2678 }
2679 };
2680 }
2681
DeclareImplicitDeductionGuideFromInitList(TemplateDecl * Template,MutableArrayRef<QualType> ParamTypes,SourceLocation Loc)2682 FunctionTemplateDecl *Sema::DeclareImplicitDeductionGuideFromInitList(
2683 TemplateDecl *Template, MutableArrayRef<QualType> ParamTypes,
2684 SourceLocation Loc) {
2685 if (CXXRecordDecl *DefRecord =
2686 cast<CXXRecordDecl>(Template->getTemplatedDecl())->getDefinition()) {
2687 if (TemplateDecl *DescribedTemplate =
2688 DefRecord->getDescribedClassTemplate())
2689 Template = DescribedTemplate;
2690 }
2691
2692 DeclContext *DC = Template->getDeclContext();
2693 if (DC->isDependentContext())
2694 return nullptr;
2695
2696 ConvertConstructorToDeductionGuideTransform Transform(
2697 *this, cast<ClassTemplateDecl>(Template));
2698 if (!isCompleteType(Loc, Transform.DeducedType))
2699 return nullptr;
2700
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,
2704 /*NewSubstitutionIndex=*/-1);
2705 // Create a template instantiation record to track the "instantiation" of
2706 // constructors into deduction guides.
2707 InstantiatingTemplate BuildingDeductionGuides(
2708 *this, Loc, Template,
2709 Sema::InstantiatingTemplate::BuildingDeductionGuidesTag{});
2710 if (BuildingDeductionGuides.isInvalid())
2711 return nullptr;
2712
2713 ClassTemplateDecl *Pattern =
2714 Transform.NestedPattern ? Transform.NestedPattern : Transform.Template;
2715 ContextRAII SavedContext(*this, Pattern->getTemplatedDecl());
2716
2717 auto *DG = cast<FunctionTemplateDecl>(
2718 Transform.buildSimpleDeductionGuide(ParamTypes));
2719 SavedContext.pop();
2720 return DG;
2721 }
2722
DeclareImplicitDeductionGuides(TemplateDecl * Template,SourceLocation Loc)2723 void Sema::DeclareImplicitDeductionGuides(TemplateDecl *Template,
2724 SourceLocation Loc) {
2725 if (CXXRecordDecl *DefRecord =
2726 cast<CXXRecordDecl>(Template->getTemplatedDecl())->getDefinition()) {
2727 if (TemplateDecl *DescribedTemplate = DefRecord->getDescribedClassTemplate())
2728 Template = DescribedTemplate;
2729 }
2730
2731 DeclContext *DC = Template->getDeclContext();
2732 if (DC->isDependentContext())
2733 return;
2734
2735 ConvertConstructorToDeductionGuideTransform Transform(
2736 *this, cast<ClassTemplateDecl>(Template));
2737 if (!isCompleteType(Loc, Transform.DeducedType))
2738 return;
2739
2740 // Check whether we've already declared deduction guides for this template.
2741 // FIXME: Consider storing a flag on the template to indicate this.
2742 auto Existing = DC->lookup(Transform.DeductionGuideName);
2743 for (auto *D : Existing)
2744 if (D->isImplicit())
2745 return;
2746
2747 // In case we were expanding a pack when we attempted to declare deduction
2748 // guides, turn off pack expansion for everything we're about to do.
2749 ArgumentPackSubstitutionIndexRAII SubstIndex(*this, -1);
2750 // Create a template instantiation record to track the "instantiation" of
2751 // constructors into deduction guides.
2752 InstantiatingTemplate BuildingDeductionGuides(
2753 *this, Loc, Template,
2754 Sema::InstantiatingTemplate::BuildingDeductionGuidesTag{});
2755 if (BuildingDeductionGuides.isInvalid())
2756 return;
2757
2758 // Convert declared constructors into deduction guide templates.
2759 // FIXME: Skip constructors for which deduction must necessarily fail (those
2760 // for which some class template parameter without a default argument never
2761 // appears in a deduced context).
2762 ClassTemplateDecl *Pattern =
2763 Transform.NestedPattern ? Transform.NestedPattern : Transform.Template;
2764 ContextRAII SavedContext(*this, Pattern->getTemplatedDecl());
2765 llvm::SmallPtrSet<NamedDecl *, 8> ProcessedCtors;
2766 bool AddedAny = false;
2767 for (NamedDecl *D : LookupConstructors(Pattern->getTemplatedDecl())) {
2768 D = D->getUnderlyingDecl();
2769 if (D->isInvalidDecl() || D->isImplicit())
2770 continue;
2771
2772 D = cast<NamedDecl>(D->getCanonicalDecl());
2773
2774 // Within C++20 modules, we may have multiple same constructors in
2775 // multiple same RecordDecls. And it doesn't make sense to create
2776 // duplicated deduction guides for the duplicated constructors.
2777 if (ProcessedCtors.count(D))
2778 continue;
2779
2780 auto *FTD = dyn_cast<FunctionTemplateDecl>(D);
2781 auto *CD =
2782 dyn_cast_or_null<CXXConstructorDecl>(FTD ? FTD->getTemplatedDecl() : D);
2783 // Class-scope explicit specializations (MS extension) do not result in
2784 // deduction guides.
2785 if (!CD || (!FTD && CD->isFunctionTemplateSpecialization()))
2786 continue;
2787
2788 // Cannot make a deduction guide when unparsed arguments are present.
2789 if (llvm::any_of(CD->parameters(), [](ParmVarDecl *P) {
2790 return !P || P->hasUnparsedDefaultArg();
2791 }))
2792 continue;
2793
2794 ProcessedCtors.insert(D);
2795 Transform.transformConstructor(FTD, CD);
2796 AddedAny = true;
2797 }
2798
2799 // C++17 [over.match.class.deduct]
2800 // -- If C is not defined or does not declare any constructors, an
2801 // additional function template derived as above from a hypothetical
2802 // constructor C().
2803 if (!AddedAny)
2804 Transform.buildSimpleDeductionGuide(std::nullopt);
2805
2806 // -- An additional function template derived as above from a hypothetical
2807 // constructor C(C), called the copy deduction candidate.
2808 cast<CXXDeductionGuideDecl>(
2809 cast<FunctionTemplateDecl>(
2810 Transform.buildSimpleDeductionGuide(Transform.DeducedType))
2811 ->getTemplatedDecl())
2812 ->setDeductionCandidateKind(DeductionCandidate::Copy);
2813
2814 SavedContext.pop();
2815 }
2816
2817 /// Diagnose the presence of a default template argument on a
2818 /// template parameter, which is ill-formed in certain contexts.
2819 ///
2820 /// \returns true if the default template argument should be dropped.
DiagnoseDefaultTemplateArgument(Sema & S,Sema::TemplateParamListContext TPC,SourceLocation ParamLoc,SourceRange DefArgRange)2821 static bool DiagnoseDefaultTemplateArgument(Sema &S,
2822 Sema::TemplateParamListContext TPC,
2823 SourceLocation ParamLoc,
2824 SourceRange DefArgRange) {
2825 switch (TPC) {
2826 case Sema::TPC_ClassTemplate:
2827 case Sema::TPC_VarTemplate:
2828 case Sema::TPC_TypeAliasTemplate:
2829 return false;
2830
2831 case Sema::TPC_FunctionTemplate:
2832 case Sema::TPC_FriendFunctionTemplateDefinition:
2833 // C++ [temp.param]p9:
2834 // A default template-argument shall not be specified in a
2835 // function template declaration or a function template
2836 // definition [...]
2837 // If a friend function template declaration specifies a default
2838 // template-argument, that declaration shall be a definition and shall be
2839 // the only declaration of the function template in the translation unit.
2840 // (C++98/03 doesn't have this wording; see DR226).
2841 S.Diag(ParamLoc, S.getLangOpts().CPlusPlus11 ?
2842 diag::warn_cxx98_compat_template_parameter_default_in_function_template
2843 : diag::ext_template_parameter_default_in_function_template)
2844 << DefArgRange;
2845 return false;
2846
2847 case Sema::TPC_ClassTemplateMember:
2848 // C++0x [temp.param]p9:
2849 // A default template-argument shall not be specified in the
2850 // template-parameter-lists of the definition of a member of a
2851 // class template that appears outside of the member's class.
2852 S.Diag(ParamLoc, diag::err_template_parameter_default_template_member)
2853 << DefArgRange;
2854 return true;
2855
2856 case Sema::TPC_FriendClassTemplate:
2857 case Sema::TPC_FriendFunctionTemplate:
2858 // C++ [temp.param]p9:
2859 // A default template-argument shall not be specified in a
2860 // friend template declaration.
2861 S.Diag(ParamLoc, diag::err_template_parameter_default_friend_template)
2862 << DefArgRange;
2863 return true;
2864
2865 // FIXME: C++0x [temp.param]p9 allows default template-arguments
2866 // for friend function templates if there is only a single
2867 // declaration (and it is a definition). Strange!
2868 }
2869
2870 llvm_unreachable("Invalid TemplateParamListContext!");
2871 }
2872
2873 /// Check for unexpanded parameter packs within the template parameters
2874 /// of a template template parameter, recursively.
DiagnoseUnexpandedParameterPacks(Sema & S,TemplateTemplateParmDecl * TTP)2875 static bool DiagnoseUnexpandedParameterPacks(Sema &S,
2876 TemplateTemplateParmDecl *TTP) {
2877 // A template template parameter which is a parameter pack is also a pack
2878 // expansion.
2879 if (TTP->isParameterPack())
2880 return false;
2881
2882 TemplateParameterList *Params = TTP->getTemplateParameters();
2883 for (unsigned I = 0, N = Params->size(); I != N; ++I) {
2884 NamedDecl *P = Params->getParam(I);
2885 if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(P)) {
2886 if (!TTP->isParameterPack())
2887 if (const TypeConstraint *TC = TTP->getTypeConstraint())
2888 if (TC->hasExplicitTemplateArgs())
2889 for (auto &ArgLoc : TC->getTemplateArgsAsWritten()->arguments())
2890 if (S.DiagnoseUnexpandedParameterPack(ArgLoc,
2891 Sema::UPPC_TypeConstraint))
2892 return true;
2893 continue;
2894 }
2895
2896 if (NonTypeTemplateParmDecl *NTTP = dyn_cast<NonTypeTemplateParmDecl>(P)) {
2897 if (!NTTP->isParameterPack() &&
2898 S.DiagnoseUnexpandedParameterPack(NTTP->getLocation(),
2899 NTTP->getTypeSourceInfo(),
2900 Sema::UPPC_NonTypeTemplateParameterType))
2901 return true;
2902
2903 continue;
2904 }
2905
2906 if (TemplateTemplateParmDecl *InnerTTP
2907 = dyn_cast<TemplateTemplateParmDecl>(P))
2908 if (DiagnoseUnexpandedParameterPacks(S, InnerTTP))
2909 return true;
2910 }
2911
2912 return false;
2913 }
2914
2915 /// Checks the validity of a template parameter list, possibly
2916 /// considering the template parameter list from a previous
2917 /// declaration.
2918 ///
2919 /// If an "old" template parameter list is provided, it must be
2920 /// equivalent (per TemplateParameterListsAreEqual) to the "new"
2921 /// template parameter list.
2922 ///
2923 /// \param NewParams Template parameter list for a new template
2924 /// declaration. This template parameter list will be updated with any
2925 /// default arguments that are carried through from the previous
2926 /// template parameter list.
2927 ///
2928 /// \param OldParams If provided, template parameter list from a
2929 /// previous declaration of the same template. Default template
2930 /// arguments will be merged from the old template parameter list to
2931 /// the new template parameter list.
2932 ///
2933 /// \param TPC Describes the context in which we are checking the given
2934 /// template parameter list.
2935 ///
2936 /// \param SkipBody If we might have already made a prior merged definition
2937 /// of this template visible, the corresponding body-skipping information.
2938 /// Default argument redefinition is not an error when skipping such a body,
2939 /// because (under the ODR) we can assume the default arguments are the same
2940 /// as the prior merged definition.
2941 ///
2942 /// \returns true if an error occurred, false otherwise.
CheckTemplateParameterList(TemplateParameterList * NewParams,TemplateParameterList * OldParams,TemplateParamListContext TPC,SkipBodyInfo * SkipBody)2943 bool Sema::CheckTemplateParameterList(TemplateParameterList *NewParams,
2944 TemplateParameterList *OldParams,
2945 TemplateParamListContext TPC,
2946 SkipBodyInfo *SkipBody) {
2947 bool Invalid = false;
2948
2949 // C++ [temp.param]p10:
2950 // The set of default template-arguments available for use with a
2951 // template declaration or definition is obtained by merging the
2952 // default arguments from the definition (if in scope) and all
2953 // declarations in scope in the same way default function
2954 // arguments are (8.3.6).
2955 bool SawDefaultArgument = false;
2956 SourceLocation PreviousDefaultArgLoc;
2957
2958 // Dummy initialization to avoid warnings.
2959 TemplateParameterList::iterator OldParam = NewParams->end();
2960 if (OldParams)
2961 OldParam = OldParams->begin();
2962
2963 bool RemoveDefaultArguments = false;
2964 for (TemplateParameterList::iterator NewParam = NewParams->begin(),
2965 NewParamEnd = NewParams->end();
2966 NewParam != NewParamEnd; ++NewParam) {
2967 // Whether we've seen a duplicate default argument in the same translation
2968 // unit.
2969 bool RedundantDefaultArg = false;
2970 // Whether we've found inconsis inconsitent default arguments in different
2971 // translation unit.
2972 bool InconsistentDefaultArg = false;
2973 // The name of the module which contains the inconsistent default argument.
2974 std::string PrevModuleName;
2975
2976 SourceLocation OldDefaultLoc;
2977 SourceLocation NewDefaultLoc;
2978
2979 // Variable used to diagnose missing default arguments
2980 bool MissingDefaultArg = false;
2981
2982 // Variable used to diagnose non-final parameter packs
2983 bool SawParameterPack = false;
2984
2985 if (TemplateTypeParmDecl *NewTypeParm
2986 = dyn_cast<TemplateTypeParmDecl>(*NewParam)) {
2987 // Check the presence of a default argument here.
2988 if (NewTypeParm->hasDefaultArgument() &&
2989 DiagnoseDefaultTemplateArgument(*this, TPC,
2990 NewTypeParm->getLocation(),
2991 NewTypeParm->getDefaultArgumentInfo()->getTypeLoc()
2992 .getSourceRange()))
2993 NewTypeParm->removeDefaultArgument();
2994
2995 // Merge default arguments for template type parameters.
2996 TemplateTypeParmDecl *OldTypeParm
2997 = OldParams? cast<TemplateTypeParmDecl>(*OldParam) : nullptr;
2998 if (NewTypeParm->isParameterPack()) {
2999 assert(!NewTypeParm->hasDefaultArgument() &&
3000 "Parameter packs can't have a default argument!");
3001 SawParameterPack = true;
3002 } else if (OldTypeParm && hasVisibleDefaultArgument(OldTypeParm) &&
3003 NewTypeParm->hasDefaultArgument() &&
3004 (!SkipBody || !SkipBody->ShouldSkip)) {
3005 OldDefaultLoc = OldTypeParm->getDefaultArgumentLoc();
3006 NewDefaultLoc = NewTypeParm->getDefaultArgumentLoc();
3007 SawDefaultArgument = true;
3008
3009 if (!OldTypeParm->getOwningModule())
3010 RedundantDefaultArg = true;
3011 else if (!getASTContext().isSameDefaultTemplateArgument(OldTypeParm,
3012 NewTypeParm)) {
3013 InconsistentDefaultArg = true;
3014 PrevModuleName =
3015 OldTypeParm->getImportedOwningModule()->getFullModuleName();
3016 }
3017 PreviousDefaultArgLoc = NewDefaultLoc;
3018 } else if (OldTypeParm && OldTypeParm->hasDefaultArgument()) {
3019 // Merge the default argument from the old declaration to the
3020 // new declaration.
3021 NewTypeParm->setInheritedDefaultArgument(Context, OldTypeParm);
3022 PreviousDefaultArgLoc = OldTypeParm->getDefaultArgumentLoc();
3023 } else if (NewTypeParm->hasDefaultArgument()) {
3024 SawDefaultArgument = true;
3025 PreviousDefaultArgLoc = NewTypeParm->getDefaultArgumentLoc();
3026 } else if (SawDefaultArgument)
3027 MissingDefaultArg = true;
3028 } else if (NonTypeTemplateParmDecl *NewNonTypeParm
3029 = dyn_cast<NonTypeTemplateParmDecl>(*NewParam)) {
3030 // Check for unexpanded parameter packs.
3031 if (!NewNonTypeParm->isParameterPack() &&
3032 DiagnoseUnexpandedParameterPack(NewNonTypeParm->getLocation(),
3033 NewNonTypeParm->getTypeSourceInfo(),
3034 UPPC_NonTypeTemplateParameterType)) {
3035 Invalid = true;
3036 continue;
3037 }
3038
3039 // Check the presence of a default argument here.
3040 if (NewNonTypeParm->hasDefaultArgument() &&
3041 DiagnoseDefaultTemplateArgument(*this, TPC,
3042 NewNonTypeParm->getLocation(),
3043 NewNonTypeParm->getDefaultArgument()->getSourceRange())) {
3044 NewNonTypeParm->removeDefaultArgument();
3045 }
3046
3047 // Merge default arguments for non-type template parameters
3048 NonTypeTemplateParmDecl *OldNonTypeParm
3049 = OldParams? cast<NonTypeTemplateParmDecl>(*OldParam) : nullptr;
3050 if (NewNonTypeParm->isParameterPack()) {
3051 assert(!NewNonTypeParm->hasDefaultArgument() &&
3052 "Parameter packs can't have a default argument!");
3053 if (!NewNonTypeParm->isPackExpansion())
3054 SawParameterPack = true;
3055 } else if (OldNonTypeParm && hasVisibleDefaultArgument(OldNonTypeParm) &&
3056 NewNonTypeParm->hasDefaultArgument() &&
3057 (!SkipBody || !SkipBody->ShouldSkip)) {
3058 OldDefaultLoc = OldNonTypeParm->getDefaultArgumentLoc();
3059 NewDefaultLoc = NewNonTypeParm->getDefaultArgumentLoc();
3060 SawDefaultArgument = true;
3061 if (!OldNonTypeParm->getOwningModule())
3062 RedundantDefaultArg = true;
3063 else if (!getASTContext().isSameDefaultTemplateArgument(
3064 OldNonTypeParm, NewNonTypeParm)) {
3065 InconsistentDefaultArg = true;
3066 PrevModuleName =
3067 OldNonTypeParm->getImportedOwningModule()->getFullModuleName();
3068 }
3069 PreviousDefaultArgLoc = NewDefaultLoc;
3070 } else if (OldNonTypeParm && OldNonTypeParm->hasDefaultArgument()) {
3071 // Merge the default argument from the old declaration to the
3072 // new declaration.
3073 NewNonTypeParm->setInheritedDefaultArgument(Context, OldNonTypeParm);
3074 PreviousDefaultArgLoc = OldNonTypeParm->getDefaultArgumentLoc();
3075 } else if (NewNonTypeParm->hasDefaultArgument()) {
3076 SawDefaultArgument = true;
3077 PreviousDefaultArgLoc = NewNonTypeParm->getDefaultArgumentLoc();
3078 } else if (SawDefaultArgument)
3079 MissingDefaultArg = true;
3080 } else {
3081 TemplateTemplateParmDecl *NewTemplateParm
3082 = cast<TemplateTemplateParmDecl>(*NewParam);
3083
3084 // Check for unexpanded parameter packs, recursively.
3085 if (::DiagnoseUnexpandedParameterPacks(*this, NewTemplateParm)) {
3086 Invalid = true;
3087 continue;
3088 }
3089
3090 // Check the presence of a default argument here.
3091 if (NewTemplateParm->hasDefaultArgument() &&
3092 DiagnoseDefaultTemplateArgument(*this, TPC,
3093 NewTemplateParm->getLocation(),
3094 NewTemplateParm->getDefaultArgument().getSourceRange()))
3095 NewTemplateParm->removeDefaultArgument();
3096
3097 // Merge default arguments for template template parameters
3098 TemplateTemplateParmDecl *OldTemplateParm
3099 = OldParams? cast<TemplateTemplateParmDecl>(*OldParam) : nullptr;
3100 if (NewTemplateParm->isParameterPack()) {
3101 assert(!NewTemplateParm->hasDefaultArgument() &&
3102 "Parameter packs can't have a default argument!");
3103 if (!NewTemplateParm->isPackExpansion())
3104 SawParameterPack = true;
3105 } else if (OldTemplateParm &&
3106 hasVisibleDefaultArgument(OldTemplateParm) &&
3107 NewTemplateParm->hasDefaultArgument() &&
3108 (!SkipBody || !SkipBody->ShouldSkip)) {
3109 OldDefaultLoc = OldTemplateParm->getDefaultArgument().getLocation();
3110 NewDefaultLoc = NewTemplateParm->getDefaultArgument().getLocation();
3111 SawDefaultArgument = true;
3112 if (!OldTemplateParm->getOwningModule())
3113 RedundantDefaultArg = true;
3114 else if (!getASTContext().isSameDefaultTemplateArgument(
3115 OldTemplateParm, NewTemplateParm)) {
3116 InconsistentDefaultArg = true;
3117 PrevModuleName =
3118 OldTemplateParm->getImportedOwningModule()->getFullModuleName();
3119 }
3120 PreviousDefaultArgLoc = NewDefaultLoc;
3121 } else if (OldTemplateParm && OldTemplateParm->hasDefaultArgument()) {
3122 // Merge the default argument from the old declaration to the
3123 // new declaration.
3124 NewTemplateParm->setInheritedDefaultArgument(Context, OldTemplateParm);
3125 PreviousDefaultArgLoc
3126 = OldTemplateParm->getDefaultArgument().getLocation();
3127 } else if (NewTemplateParm->hasDefaultArgument()) {
3128 SawDefaultArgument = true;
3129 PreviousDefaultArgLoc
3130 = NewTemplateParm->getDefaultArgument().getLocation();
3131 } else if (SawDefaultArgument)
3132 MissingDefaultArg = true;
3133 }
3134
3135 // C++11 [temp.param]p11:
3136 // If a template parameter of a primary class template or alias template
3137 // is a template parameter pack, it shall be the last template parameter.
3138 if (SawParameterPack && (NewParam + 1) != NewParamEnd &&
3139 (TPC == TPC_ClassTemplate || TPC == TPC_VarTemplate ||
3140 TPC == TPC_TypeAliasTemplate)) {
3141 Diag((*NewParam)->getLocation(),
3142 diag::err_template_param_pack_must_be_last_template_parameter);
3143 Invalid = true;
3144 }
3145
3146 // [basic.def.odr]/13:
3147 // There can be more than one definition of a
3148 // ...
3149 // default template argument
3150 // ...
3151 // in a program provided that each definition appears in a different
3152 // translation unit and the definitions satisfy the [same-meaning
3153 // criteria of the ODR].
3154 //
3155 // Simply, the design of modules allows the definition of template default
3156 // argument to be repeated across translation unit. Note that the ODR is
3157 // checked elsewhere. But it is still not allowed to repeat template default
3158 // argument in the same translation unit.
3159 if (RedundantDefaultArg) {
3160 Diag(NewDefaultLoc, diag::err_template_param_default_arg_redefinition);
3161 Diag(OldDefaultLoc, diag::note_template_param_prev_default_arg);
3162 Invalid = true;
3163 } else if (InconsistentDefaultArg) {
3164 // We could only diagnose about the case that the OldParam is imported.
3165 // The case NewParam is imported should be handled in ASTReader.
3166 Diag(NewDefaultLoc,
3167 diag::err_template_param_default_arg_inconsistent_redefinition);
3168 Diag(OldDefaultLoc,
3169 diag::note_template_param_prev_default_arg_in_other_module)
3170 << PrevModuleName;
3171 Invalid = true;
3172 } else if (MissingDefaultArg && TPC != TPC_FunctionTemplate) {
3173 // C++ [temp.param]p11:
3174 // If a template-parameter of a class template has a default
3175 // template-argument, each subsequent template-parameter shall either
3176 // have a default template-argument supplied or be a template parameter
3177 // pack.
3178 Diag((*NewParam)->getLocation(),
3179 diag::err_template_param_default_arg_missing);
3180 Diag(PreviousDefaultArgLoc, diag::note_template_param_prev_default_arg);
3181 Invalid = true;
3182 RemoveDefaultArguments = true;
3183 }
3184
3185 // If we have an old template parameter list that we're merging
3186 // in, move on to the next parameter.
3187 if (OldParams)
3188 ++OldParam;
3189 }
3190
3191 // We were missing some default arguments at the end of the list, so remove
3192 // all of the default arguments.
3193 if (RemoveDefaultArguments) {
3194 for (TemplateParameterList::iterator NewParam = NewParams->begin(),
3195 NewParamEnd = NewParams->end();
3196 NewParam != NewParamEnd; ++NewParam) {
3197 if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(*NewParam))
3198 TTP->removeDefaultArgument();
3199 else if (NonTypeTemplateParmDecl *NTTP
3200 = dyn_cast<NonTypeTemplateParmDecl>(*NewParam))
3201 NTTP->removeDefaultArgument();
3202 else
3203 cast<TemplateTemplateParmDecl>(*NewParam)->removeDefaultArgument();
3204 }
3205 }
3206
3207 return Invalid;
3208 }
3209
3210 namespace {
3211
3212 /// A class which looks for a use of a certain level of template
3213 /// parameter.
3214 struct DependencyChecker : RecursiveASTVisitor<DependencyChecker> {
3215 typedef RecursiveASTVisitor<DependencyChecker> super;
3216
3217 unsigned Depth;
3218
3219 // Whether we're looking for a use of a template parameter that makes the
3220 // overall construct type-dependent / a dependent type. This is strictly
3221 // best-effort for now; we may fail to match at all for a dependent type
3222 // in some cases if this is set.
3223 bool IgnoreNonTypeDependent;
3224
3225 bool Match;
3226 SourceLocation MatchLoc;
3227
DependencyChecker__anonb04a1dd90b11::DependencyChecker3228 DependencyChecker(unsigned Depth, bool IgnoreNonTypeDependent)
3229 : Depth(Depth), IgnoreNonTypeDependent(IgnoreNonTypeDependent),
3230 Match(false) {}
3231
DependencyChecker__anonb04a1dd90b11::DependencyChecker3232 DependencyChecker(TemplateParameterList *Params, bool IgnoreNonTypeDependent)
3233 : IgnoreNonTypeDependent(IgnoreNonTypeDependent), Match(false) {
3234 NamedDecl *ND = Params->getParam(0);
3235 if (TemplateTypeParmDecl *PD = dyn_cast<TemplateTypeParmDecl>(ND)) {
3236 Depth = PD->getDepth();
3237 } else if (NonTypeTemplateParmDecl *PD =
3238 dyn_cast<NonTypeTemplateParmDecl>(ND)) {
3239 Depth = PD->getDepth();
3240 } else {
3241 Depth = cast<TemplateTemplateParmDecl>(ND)->getDepth();
3242 }
3243 }
3244
Matches__anonb04a1dd90b11::DependencyChecker3245 bool Matches(unsigned ParmDepth, SourceLocation Loc = SourceLocation()) {
3246 if (ParmDepth >= Depth) {
3247 Match = true;
3248 MatchLoc = Loc;
3249 return true;
3250 }
3251 return false;
3252 }
3253
TraverseStmt__anonb04a1dd90b11::DependencyChecker3254 bool TraverseStmt(Stmt *S, DataRecursionQueue *Q = nullptr) {
3255 // Prune out non-type-dependent expressions if requested. This can
3256 // sometimes result in us failing to find a template parameter reference
3257 // (if a value-dependent expression creates a dependent type), but this
3258 // mode is best-effort only.
3259 if (auto *E = dyn_cast_or_null<Expr>(S))
3260 if (IgnoreNonTypeDependent && !E->isTypeDependent())
3261 return true;
3262 return super::TraverseStmt(S, Q);
3263 }
3264
TraverseTypeLoc__anonb04a1dd90b11::DependencyChecker3265 bool TraverseTypeLoc(TypeLoc TL) {
3266 if (IgnoreNonTypeDependent && !TL.isNull() &&
3267 !TL.getType()->isDependentType())
3268 return true;
3269 return super::TraverseTypeLoc(TL);
3270 }
3271
VisitTemplateTypeParmTypeLoc__anonb04a1dd90b11::DependencyChecker3272 bool VisitTemplateTypeParmTypeLoc(TemplateTypeParmTypeLoc TL) {
3273 return !Matches(TL.getTypePtr()->getDepth(), TL.getNameLoc());
3274 }
3275
VisitTemplateTypeParmType__anonb04a1dd90b11::DependencyChecker3276 bool VisitTemplateTypeParmType(const TemplateTypeParmType *T) {
3277 // For a best-effort search, keep looking until we find a location.
3278 return IgnoreNonTypeDependent || !Matches(T->getDepth());
3279 }
3280
TraverseTemplateName__anonb04a1dd90b11::DependencyChecker3281 bool TraverseTemplateName(TemplateName N) {
3282 if (TemplateTemplateParmDecl *PD =
3283 dyn_cast_or_null<TemplateTemplateParmDecl>(N.getAsTemplateDecl()))
3284 if (Matches(PD->getDepth()))
3285 return false;
3286 return super::TraverseTemplateName(N);
3287 }
3288
VisitDeclRefExpr__anonb04a1dd90b11::DependencyChecker3289 bool VisitDeclRefExpr(DeclRefExpr *E) {
3290 if (NonTypeTemplateParmDecl *PD =
3291 dyn_cast<NonTypeTemplateParmDecl>(E->getDecl()))
3292 if (Matches(PD->getDepth(), E->getExprLoc()))
3293 return false;
3294 return super::VisitDeclRefExpr(E);
3295 }
3296
VisitSubstTemplateTypeParmType__anonb04a1dd90b11::DependencyChecker3297 bool VisitSubstTemplateTypeParmType(const SubstTemplateTypeParmType *T) {
3298 return TraverseType(T->getReplacementType());
3299 }
3300
3301 bool
VisitSubstTemplateTypeParmPackType__anonb04a1dd90b11::DependencyChecker3302 VisitSubstTemplateTypeParmPackType(const SubstTemplateTypeParmPackType *T) {
3303 return TraverseTemplateArgument(T->getArgumentPack());
3304 }
3305
TraverseInjectedClassNameType__anonb04a1dd90b11::DependencyChecker3306 bool TraverseInjectedClassNameType(const InjectedClassNameType *T) {
3307 return TraverseType(T->getInjectedSpecializationType());
3308 }
3309 };
3310 } // end anonymous namespace
3311
3312 /// Determines whether a given type depends on the given parameter
3313 /// list.
3314 static bool
DependsOnTemplateParameters(QualType T,TemplateParameterList * Params)3315 DependsOnTemplateParameters(QualType T, TemplateParameterList *Params) {
3316 if (!Params->size())
3317 return false;
3318
3319 DependencyChecker Checker(Params, /*IgnoreNonTypeDependent*/false);
3320 Checker.TraverseType(T);
3321 return Checker.Match;
3322 }
3323
3324 // Find the source range corresponding to the named type in the given
3325 // nested-name-specifier, if any.
getRangeOfTypeInNestedNameSpecifier(ASTContext & Context,QualType T,const CXXScopeSpec & SS)3326 static SourceRange getRangeOfTypeInNestedNameSpecifier(ASTContext &Context,
3327 QualType T,
3328 const CXXScopeSpec &SS) {
3329 NestedNameSpecifierLoc NNSLoc(SS.getScopeRep(), SS.location_data());
3330 while (NestedNameSpecifier *NNS = NNSLoc.getNestedNameSpecifier()) {
3331 if (const Type *CurType = NNS->getAsType()) {
3332 if (Context.hasSameUnqualifiedType(T, QualType(CurType, 0)))
3333 return NNSLoc.getTypeLoc().getSourceRange();
3334 } else
3335 break;
3336
3337 NNSLoc = NNSLoc.getPrefix();
3338 }
3339
3340 return SourceRange();
3341 }
3342
3343 /// Match the given template parameter lists to the given scope
3344 /// specifier, returning the template parameter list that applies to the
3345 /// name.
3346 ///
3347 /// \param DeclStartLoc the start of the declaration that has a scope
3348 /// specifier or a template parameter list.
3349 ///
3350 /// \param DeclLoc The location of the declaration itself.
3351 ///
3352 /// \param SS the scope specifier that will be matched to the given template
3353 /// parameter lists. This scope specifier precedes a qualified name that is
3354 /// being declared.
3355 ///
3356 /// \param TemplateId The template-id following the scope specifier, if there
3357 /// is one. Used to check for a missing 'template<>'.
3358 ///
3359 /// \param ParamLists the template parameter lists, from the outermost to the
3360 /// innermost template parameter lists.
3361 ///
3362 /// \param IsFriend Whether to apply the slightly different rules for
3363 /// matching template parameters to scope specifiers in friend
3364 /// declarations.
3365 ///
3366 /// \param IsMemberSpecialization will be set true if the scope specifier
3367 /// denotes a fully-specialized type, and therefore this is a declaration of
3368 /// a member specialization.
3369 ///
3370 /// \returns the template parameter list, if any, that corresponds to the
3371 /// name that is preceded by the scope specifier @p SS. This template
3372 /// parameter list may have template parameters (if we're declaring a
3373 /// template) or may have no template parameters (if we're declaring a
3374 /// template specialization), or may be NULL (if what we're declaring isn't
3375 /// itself a template).
MatchTemplateParametersToScopeSpecifier(SourceLocation DeclStartLoc,SourceLocation DeclLoc,const CXXScopeSpec & SS,TemplateIdAnnotation * TemplateId,ArrayRef<TemplateParameterList * > ParamLists,bool IsFriend,bool & IsMemberSpecialization,bool & Invalid,bool SuppressDiagnostic)3376 TemplateParameterList *Sema::MatchTemplateParametersToScopeSpecifier(
3377 SourceLocation DeclStartLoc, SourceLocation DeclLoc, const CXXScopeSpec &SS,
3378 TemplateIdAnnotation *TemplateId,
3379 ArrayRef<TemplateParameterList *> ParamLists, bool IsFriend,
3380 bool &IsMemberSpecialization, bool &Invalid, bool SuppressDiagnostic) {
3381 IsMemberSpecialization = false;
3382 Invalid = false;
3383
3384 // The sequence of nested types to which we will match up the template
3385 // parameter lists. We first build this list by starting with the type named
3386 // by the nested-name-specifier and walking out until we run out of types.
3387 SmallVector<QualType, 4> NestedTypes;
3388 QualType T;
3389 if (SS.getScopeRep()) {
3390 if (CXXRecordDecl *Record
3391 = dyn_cast_or_null<CXXRecordDecl>(computeDeclContext(SS, true)))
3392 T = Context.getTypeDeclType(Record);
3393 else
3394 T = QualType(SS.getScopeRep()->getAsType(), 0);
3395 }
3396
3397 // If we found an explicit specialization that prevents us from needing
3398 // 'template<>' headers, this will be set to the location of that
3399 // explicit specialization.
3400 SourceLocation ExplicitSpecLoc;
3401
3402 while (!T.isNull()) {
3403 NestedTypes.push_back(T);
3404
3405 // Retrieve the parent of a record type.
3406 if (CXXRecordDecl *Record = T->getAsCXXRecordDecl()) {
3407 // If this type is an explicit specialization, we're done.
3408 if (ClassTemplateSpecializationDecl *Spec
3409 = dyn_cast<ClassTemplateSpecializationDecl>(Record)) {
3410 if (!isa<ClassTemplatePartialSpecializationDecl>(Spec) &&
3411 Spec->getSpecializationKind() == TSK_ExplicitSpecialization) {
3412 ExplicitSpecLoc = Spec->getLocation();
3413 break;
3414 }
3415 } else if (Record->getTemplateSpecializationKind()
3416 == TSK_ExplicitSpecialization) {
3417 ExplicitSpecLoc = Record->getLocation();
3418 break;
3419 }
3420
3421 if (TypeDecl *Parent = dyn_cast<TypeDecl>(Record->getParent()))
3422 T = Context.getTypeDeclType(Parent);
3423 else
3424 T = QualType();
3425 continue;
3426 }
3427
3428 if (const TemplateSpecializationType *TST
3429 = T->getAs<TemplateSpecializationType>()) {
3430 if (TemplateDecl *Template = TST->getTemplateName().getAsTemplateDecl()) {
3431 if (TypeDecl *Parent = dyn_cast<TypeDecl>(Template->getDeclContext()))
3432 T = Context.getTypeDeclType(Parent);
3433 else
3434 T = QualType();
3435 continue;
3436 }
3437 }
3438
3439 // Look one step prior in a dependent template specialization type.
3440 if (const DependentTemplateSpecializationType *DependentTST
3441 = T->getAs<DependentTemplateSpecializationType>()) {
3442 if (NestedNameSpecifier *NNS = DependentTST->getQualifier())
3443 T = QualType(NNS->getAsType(), 0);
3444 else
3445 T = QualType();
3446 continue;
3447 }
3448
3449 // Look one step prior in a dependent name type.
3450 if (const DependentNameType *DependentName = T->getAs<DependentNameType>()){
3451 if (NestedNameSpecifier *NNS = DependentName->getQualifier())
3452 T = QualType(NNS->getAsType(), 0);
3453 else
3454 T = QualType();
3455 continue;
3456 }
3457
3458 // Retrieve the parent of an enumeration type.
3459 if (const EnumType *EnumT = T->getAs<EnumType>()) {
3460 // FIXME: Forward-declared enums require a TSK_ExplicitSpecialization
3461 // check here.
3462 EnumDecl *Enum = EnumT->getDecl();
3463
3464 // Get to the parent type.
3465 if (TypeDecl *Parent = dyn_cast<TypeDecl>(Enum->getParent()))
3466 T = Context.getTypeDeclType(Parent);
3467 else
3468 T = QualType();
3469 continue;
3470 }
3471
3472 T = QualType();
3473 }
3474 // Reverse the nested types list, since we want to traverse from the outermost
3475 // to the innermost while checking template-parameter-lists.
3476 std::reverse(NestedTypes.begin(), NestedTypes.end());
3477
3478 // C++0x [temp.expl.spec]p17:
3479 // A member or a member template may be nested within many
3480 // enclosing class templates. In an explicit specialization for
3481 // such a member, the member declaration shall be preceded by a
3482 // template<> for each enclosing class template that is
3483 // explicitly specialized.
3484 bool SawNonEmptyTemplateParameterList = false;
3485
3486 auto CheckExplicitSpecialization = [&](SourceRange Range, bool Recovery) {
3487 if (SawNonEmptyTemplateParameterList) {
3488 if (!SuppressDiagnostic)
3489 Diag(DeclLoc, diag::err_specialize_member_of_template)
3490 << !Recovery << Range;
3491 Invalid = true;
3492 IsMemberSpecialization = false;
3493 return true;
3494 }
3495
3496 return false;
3497 };
3498
3499 auto DiagnoseMissingExplicitSpecialization = [&] (SourceRange Range) {
3500 // Check that we can have an explicit specialization here.
3501 if (CheckExplicitSpecialization(Range, true))
3502 return true;
3503
3504 // We don't have a template header, but we should.
3505 SourceLocation ExpectedTemplateLoc;
3506 if (!ParamLists.empty())
3507 ExpectedTemplateLoc = ParamLists[0]->getTemplateLoc();
3508 else
3509 ExpectedTemplateLoc = DeclStartLoc;
3510
3511 if (!SuppressDiagnostic)
3512 Diag(DeclLoc, diag::err_template_spec_needs_header)
3513 << Range
3514 << FixItHint::CreateInsertion(ExpectedTemplateLoc, "template<> ");
3515 return false;
3516 };
3517
3518 unsigned ParamIdx = 0;
3519 for (unsigned TypeIdx = 0, NumTypes = NestedTypes.size(); TypeIdx != NumTypes;
3520 ++TypeIdx) {
3521 T = NestedTypes[TypeIdx];
3522
3523 // Whether we expect a 'template<>' header.
3524 bool NeedEmptyTemplateHeader = false;
3525
3526 // Whether we expect a template header with parameters.
3527 bool NeedNonemptyTemplateHeader = false;
3528
3529 // For a dependent type, the set of template parameters that we
3530 // expect to see.
3531 TemplateParameterList *ExpectedTemplateParams = nullptr;
3532
3533 // C++0x [temp.expl.spec]p15:
3534 // A member or a member template may be nested within many enclosing
3535 // class templates. In an explicit specialization for such a member, the
3536 // member declaration shall be preceded by a template<> for each
3537 // enclosing class template that is explicitly specialized.
3538 if (CXXRecordDecl *Record = T->getAsCXXRecordDecl()) {
3539 if (ClassTemplatePartialSpecializationDecl *Partial
3540 = dyn_cast<ClassTemplatePartialSpecializationDecl>(Record)) {
3541 ExpectedTemplateParams = Partial->getTemplateParameters();
3542 NeedNonemptyTemplateHeader = true;
3543 } else if (Record->isDependentType()) {
3544 if (Record->getDescribedClassTemplate()) {
3545 ExpectedTemplateParams = Record->getDescribedClassTemplate()
3546 ->getTemplateParameters();
3547 NeedNonemptyTemplateHeader = true;
3548 }
3549 } else if (ClassTemplateSpecializationDecl *Spec
3550 = dyn_cast<ClassTemplateSpecializationDecl>(Record)) {
3551 // C++0x [temp.expl.spec]p4:
3552 // Members of an explicitly specialized class template are defined
3553 // in the same manner as members of normal classes, and not using
3554 // the template<> syntax.
3555 if (Spec->getSpecializationKind() != TSK_ExplicitSpecialization)
3556 NeedEmptyTemplateHeader = true;
3557 else
3558 continue;
3559 } else if (Record->getTemplateSpecializationKind()) {
3560 if (Record->getTemplateSpecializationKind()
3561 != TSK_ExplicitSpecialization &&
3562 TypeIdx == NumTypes - 1)
3563 IsMemberSpecialization = true;
3564
3565 continue;
3566 }
3567 } else if (const TemplateSpecializationType *TST
3568 = T->getAs<TemplateSpecializationType>()) {
3569 if (TemplateDecl *Template = TST->getTemplateName().getAsTemplateDecl()) {
3570 ExpectedTemplateParams = Template->getTemplateParameters();
3571 NeedNonemptyTemplateHeader = true;
3572 }
3573 } else if (T->getAs<DependentTemplateSpecializationType>()) {
3574 // FIXME: We actually could/should check the template arguments here
3575 // against the corresponding template parameter list.
3576 NeedNonemptyTemplateHeader = false;
3577 }
3578
3579 // C++ [temp.expl.spec]p16:
3580 // In an explicit specialization declaration for a member of a class
3581 // template or a member template that ap- pears in namespace scope, the
3582 // member template and some of its enclosing class templates may remain
3583 // unspecialized, except that the declaration shall not explicitly
3584 // specialize a class member template if its en- closing class templates
3585 // are not explicitly specialized as well.
3586 if (ParamIdx < ParamLists.size()) {
3587 if (ParamLists[ParamIdx]->size() == 0) {
3588 if (CheckExplicitSpecialization(ParamLists[ParamIdx]->getSourceRange(),
3589 false))
3590 return nullptr;
3591 } else
3592 SawNonEmptyTemplateParameterList = true;
3593 }
3594
3595 if (NeedEmptyTemplateHeader) {
3596 // If we're on the last of the types, and we need a 'template<>' header
3597 // here, then it's a member specialization.
3598 if (TypeIdx == NumTypes - 1)
3599 IsMemberSpecialization = true;
3600
3601 if (ParamIdx < ParamLists.size()) {
3602 if (ParamLists[ParamIdx]->size() > 0) {
3603 // The header has template parameters when it shouldn't. Complain.
3604 if (!SuppressDiagnostic)
3605 Diag(ParamLists[ParamIdx]->getTemplateLoc(),
3606 diag::err_template_param_list_matches_nontemplate)
3607 << T
3608 << SourceRange(ParamLists[ParamIdx]->getLAngleLoc(),
3609 ParamLists[ParamIdx]->getRAngleLoc())
3610 << getRangeOfTypeInNestedNameSpecifier(Context, T, SS);
3611 Invalid = true;
3612 return nullptr;
3613 }
3614
3615 // Consume this template header.
3616 ++ParamIdx;
3617 continue;
3618 }
3619
3620 if (!IsFriend)
3621 if (DiagnoseMissingExplicitSpecialization(
3622 getRangeOfTypeInNestedNameSpecifier(Context, T, SS)))
3623 return nullptr;
3624
3625 continue;
3626 }
3627
3628 if (NeedNonemptyTemplateHeader) {
3629 // In friend declarations we can have template-ids which don't
3630 // depend on the corresponding template parameter lists. But
3631 // assume that empty parameter lists are supposed to match this
3632 // template-id.
3633 if (IsFriend && T->isDependentType()) {
3634 if (ParamIdx < ParamLists.size() &&
3635 DependsOnTemplateParameters(T, ParamLists[ParamIdx]))
3636 ExpectedTemplateParams = nullptr;
3637 else
3638 continue;
3639 }
3640
3641 if (ParamIdx < ParamLists.size()) {
3642 // Check the template parameter list, if we can.
3643 if (ExpectedTemplateParams &&
3644 !TemplateParameterListsAreEqual(ParamLists[ParamIdx],
3645 ExpectedTemplateParams,
3646 !SuppressDiagnostic, TPL_TemplateMatch))
3647 Invalid = true;
3648
3649 if (!Invalid &&
3650 CheckTemplateParameterList(ParamLists[ParamIdx], nullptr,
3651 TPC_ClassTemplateMember))
3652 Invalid = true;
3653
3654 ++ParamIdx;
3655 continue;
3656 }
3657
3658 if (!SuppressDiagnostic)
3659 Diag(DeclLoc, diag::err_template_spec_needs_template_parameters)
3660 << T
3661 << getRangeOfTypeInNestedNameSpecifier(Context, T, SS);
3662 Invalid = true;
3663 continue;
3664 }
3665 }
3666
3667 // If there were at least as many template-ids as there were template
3668 // parameter lists, then there are no template parameter lists remaining for
3669 // the declaration itself.
3670 if (ParamIdx >= ParamLists.size()) {
3671 if (TemplateId && !IsFriend) {
3672 // We don't have a template header for the declaration itself, but we
3673 // should.
3674 DiagnoseMissingExplicitSpecialization(SourceRange(TemplateId->LAngleLoc,
3675 TemplateId->RAngleLoc));
3676
3677 // Fabricate an empty template parameter list for the invented header.
3678 return TemplateParameterList::Create(Context, SourceLocation(),
3679 SourceLocation(), std::nullopt,
3680 SourceLocation(), nullptr);
3681 }
3682
3683 return nullptr;
3684 }
3685
3686 // If there were too many template parameter lists, complain about that now.
3687 if (ParamIdx < ParamLists.size() - 1) {
3688 bool HasAnyExplicitSpecHeader = false;
3689 bool AllExplicitSpecHeaders = true;
3690 for (unsigned I = ParamIdx, E = ParamLists.size() - 1; I != E; ++I) {
3691 if (ParamLists[I]->size() == 0)
3692 HasAnyExplicitSpecHeader = true;
3693 else
3694 AllExplicitSpecHeaders = false;
3695 }
3696
3697 if (!SuppressDiagnostic)
3698 Diag(ParamLists[ParamIdx]->getTemplateLoc(),
3699 AllExplicitSpecHeaders ? diag::warn_template_spec_extra_headers
3700 : diag::err_template_spec_extra_headers)
3701 << SourceRange(ParamLists[ParamIdx]->getTemplateLoc(),
3702 ParamLists[ParamLists.size() - 2]->getRAngleLoc());
3703
3704 // If there was a specialization somewhere, such that 'template<>' is
3705 // not required, and there were any 'template<>' headers, note where the
3706 // specialization occurred.
3707 if (ExplicitSpecLoc.isValid() && HasAnyExplicitSpecHeader &&
3708 !SuppressDiagnostic)
3709 Diag(ExplicitSpecLoc,
3710 diag::note_explicit_template_spec_does_not_need_header)
3711 << NestedTypes.back();
3712
3713 // We have a template parameter list with no corresponding scope, which
3714 // means that the resulting template declaration can't be instantiated
3715 // properly (we'll end up with dependent nodes when we shouldn't).
3716 if (!AllExplicitSpecHeaders)
3717 Invalid = true;
3718 }
3719
3720 // C++ [temp.expl.spec]p16:
3721 // In an explicit specialization declaration for a member of a class
3722 // template or a member template that ap- pears in namespace scope, the
3723 // member template and some of its enclosing class templates may remain
3724 // unspecialized, except that the declaration shall not explicitly
3725 // specialize a class member template if its en- closing class templates
3726 // are not explicitly specialized as well.
3727 if (ParamLists.back()->size() == 0 &&
3728 CheckExplicitSpecialization(ParamLists[ParamIdx]->getSourceRange(),
3729 false))
3730 return nullptr;
3731
3732 // Return the last template parameter list, which corresponds to the
3733 // entity being declared.
3734 return ParamLists.back();
3735 }
3736
NoteAllFoundTemplates(TemplateName Name)3737 void Sema::NoteAllFoundTemplates(TemplateName Name) {
3738 if (TemplateDecl *Template = Name.getAsTemplateDecl()) {
3739 Diag(Template->getLocation(), diag::note_template_declared_here)
3740 << (isa<FunctionTemplateDecl>(Template)
3741 ? 0
3742 : isa<ClassTemplateDecl>(Template)
3743 ? 1
3744 : isa<VarTemplateDecl>(Template)
3745 ? 2
3746 : isa<TypeAliasTemplateDecl>(Template) ? 3 : 4)
3747 << Template->getDeclName();
3748 return;
3749 }
3750
3751 if (OverloadedTemplateStorage *OST = Name.getAsOverloadedTemplate()) {
3752 for (OverloadedTemplateStorage::iterator I = OST->begin(),
3753 IEnd = OST->end();
3754 I != IEnd; ++I)
3755 Diag((*I)->getLocation(), diag::note_template_declared_here)
3756 << 0 << (*I)->getDeclName();
3757
3758 return;
3759 }
3760 }
3761
3762 static QualType
checkBuiltinTemplateIdType(Sema & SemaRef,BuiltinTemplateDecl * BTD,ArrayRef<TemplateArgument> Converted,SourceLocation TemplateLoc,TemplateArgumentListInfo & TemplateArgs)3763 checkBuiltinTemplateIdType(Sema &SemaRef, BuiltinTemplateDecl *BTD,
3764 ArrayRef<TemplateArgument> Converted,
3765 SourceLocation TemplateLoc,
3766 TemplateArgumentListInfo &TemplateArgs) {
3767 ASTContext &Context = SemaRef.getASTContext();
3768
3769 switch (BTD->getBuiltinTemplateKind()) {
3770 case BTK__make_integer_seq: {
3771 // Specializations of __make_integer_seq<S, T, N> are treated like
3772 // S<T, 0, ..., N-1>.
3773
3774 QualType OrigType = Converted[1].getAsType();
3775 // C++14 [inteseq.intseq]p1:
3776 // T shall be an integer type.
3777 if (!OrigType->isDependentType() && !OrigType->isIntegralType(Context)) {
3778 SemaRef.Diag(TemplateArgs[1].getLocation(),
3779 diag::err_integer_sequence_integral_element_type);
3780 return QualType();
3781 }
3782
3783 TemplateArgument NumArgsArg = Converted[2];
3784 if (NumArgsArg.isDependent())
3785 return Context.getCanonicalTemplateSpecializationType(TemplateName(BTD),
3786 Converted);
3787
3788 TemplateArgumentListInfo SyntheticTemplateArgs;
3789 // The type argument, wrapped in substitution sugar, gets reused as the
3790 // first template argument in the synthetic template argument list.
3791 SyntheticTemplateArgs.addArgument(
3792 TemplateArgumentLoc(TemplateArgument(OrigType),
3793 SemaRef.Context.getTrivialTypeSourceInfo(
3794 OrigType, TemplateArgs[1].getLocation())));
3795
3796 if (llvm::APSInt NumArgs = NumArgsArg.getAsIntegral(); NumArgs >= 0) {
3797 // Expand N into 0 ... N-1.
3798 for (llvm::APSInt I(NumArgs.getBitWidth(), NumArgs.isUnsigned());
3799 I < NumArgs; ++I) {
3800 TemplateArgument TA(Context, I, OrigType);
3801 SyntheticTemplateArgs.addArgument(SemaRef.getTrivialTemplateArgumentLoc(
3802 TA, OrigType, TemplateArgs[2].getLocation()));
3803 }
3804 } else {
3805 // C++14 [inteseq.make]p1:
3806 // If N is negative the program is ill-formed.
3807 SemaRef.Diag(TemplateArgs[2].getLocation(),
3808 diag::err_integer_sequence_negative_length);
3809 return QualType();
3810 }
3811
3812 // The first template argument will be reused as the template decl that
3813 // our synthetic template arguments will be applied to.
3814 return SemaRef.CheckTemplateIdType(Converted[0].getAsTemplate(),
3815 TemplateLoc, SyntheticTemplateArgs);
3816 }
3817
3818 case BTK__type_pack_element:
3819 // Specializations of
3820 // __type_pack_element<Index, T_1, ..., T_N>
3821 // are treated like T_Index.
3822 assert(Converted.size() == 2 &&
3823 "__type_pack_element should be given an index and a parameter pack");
3824
3825 TemplateArgument IndexArg = Converted[0], Ts = Converted[1];
3826 if (IndexArg.isDependent() || Ts.isDependent())
3827 return Context.getCanonicalTemplateSpecializationType(TemplateName(BTD),
3828 Converted);
3829
3830 llvm::APSInt Index = IndexArg.getAsIntegral();
3831 assert(Index >= 0 && "the index used with __type_pack_element should be of "
3832 "type std::size_t, and hence be non-negative");
3833 // If the Index is out of bounds, the program is ill-formed.
3834 if (Index >= Ts.pack_size()) {
3835 SemaRef.Diag(TemplateArgs[0].getLocation(),
3836 diag::err_type_pack_element_out_of_bounds);
3837 return QualType();
3838 }
3839
3840 // We simply return the type at index `Index`.
3841 int64_t N = Index.getExtValue();
3842 return Ts.getPackAsArray()[N].getAsType();
3843 }
3844 llvm_unreachable("unexpected BuiltinTemplateDecl!");
3845 }
3846
3847 /// Determine whether this alias template is "enable_if_t".
3848 /// libc++ >=14 uses "__enable_if_t" in C++11 mode.
isEnableIfAliasTemplate(TypeAliasTemplateDecl * AliasTemplate)3849 static bool isEnableIfAliasTemplate(TypeAliasTemplateDecl *AliasTemplate) {
3850 return AliasTemplate->getName().equals("enable_if_t") ||
3851 AliasTemplate->getName().equals("__enable_if_t");
3852 }
3853
3854 /// Collect all of the separable terms in the given condition, which
3855 /// might be a conjunction.
3856 ///
3857 /// FIXME: The right answer is to convert the logical expression into
3858 /// disjunctive normal form, so we can find the first failed term
3859 /// within each possible clause.
collectConjunctionTerms(Expr * Clause,SmallVectorImpl<Expr * > & Terms)3860 static void collectConjunctionTerms(Expr *Clause,
3861 SmallVectorImpl<Expr *> &Terms) {
3862 if (auto BinOp = dyn_cast<BinaryOperator>(Clause->IgnoreParenImpCasts())) {
3863 if (BinOp->getOpcode() == BO_LAnd) {
3864 collectConjunctionTerms(BinOp->getLHS(), Terms);
3865 collectConjunctionTerms(BinOp->getRHS(), Terms);
3866 return;
3867 }
3868 }
3869
3870 Terms.push_back(Clause);
3871 }
3872
3873 // The ranges-v3 library uses an odd pattern of a top-level "||" with
3874 // a left-hand side that is value-dependent but never true. Identify
3875 // the idiom and ignore that term.
lookThroughRangesV3Condition(Preprocessor & PP,Expr * Cond)3876 static Expr *lookThroughRangesV3Condition(Preprocessor &PP, Expr *Cond) {
3877 // Top-level '||'.
3878 auto *BinOp = dyn_cast<BinaryOperator>(Cond->IgnoreParenImpCasts());
3879 if (!BinOp) return Cond;
3880
3881 if (BinOp->getOpcode() != BO_LOr) return Cond;
3882
3883 // With an inner '==' that has a literal on the right-hand side.
3884 Expr *LHS = BinOp->getLHS();
3885 auto *InnerBinOp = dyn_cast<BinaryOperator>(LHS->IgnoreParenImpCasts());
3886 if (!InnerBinOp) return Cond;
3887
3888 if (InnerBinOp->getOpcode() != BO_EQ ||
3889 !isa<IntegerLiteral>(InnerBinOp->getRHS()))
3890 return Cond;
3891
3892 // If the inner binary operation came from a macro expansion named
3893 // CONCEPT_REQUIRES or CONCEPT_REQUIRES_, return the right-hand side
3894 // of the '||', which is the real, user-provided condition.
3895 SourceLocation Loc = InnerBinOp->getExprLoc();
3896 if (!Loc.isMacroID()) return Cond;
3897
3898 StringRef MacroName = PP.getImmediateMacroName(Loc);
3899 if (MacroName == "CONCEPT_REQUIRES" || MacroName == "CONCEPT_REQUIRES_")
3900 return BinOp->getRHS();
3901
3902 return Cond;
3903 }
3904
3905 namespace {
3906
3907 // A PrinterHelper that prints more helpful diagnostics for some sub-expressions
3908 // within failing boolean expression, such as substituting template parameters
3909 // for actual types.
3910 class FailedBooleanConditionPrinterHelper : public PrinterHelper {
3911 public:
FailedBooleanConditionPrinterHelper(const PrintingPolicy & P)3912 explicit FailedBooleanConditionPrinterHelper(const PrintingPolicy &P)
3913 : Policy(P) {}
3914
handledStmt(Stmt * E,raw_ostream & OS)3915 bool handledStmt(Stmt *E, raw_ostream &OS) override {
3916 const auto *DR = dyn_cast<DeclRefExpr>(E);
3917 if (DR && DR->getQualifier()) {
3918 // If this is a qualified name, expand the template arguments in nested
3919 // qualifiers.
3920 DR->getQualifier()->print(OS, Policy, true);
3921 // Then print the decl itself.
3922 const ValueDecl *VD = DR->getDecl();
3923 OS << VD->getName();
3924 if (const auto *IV = dyn_cast<VarTemplateSpecializationDecl>(VD)) {
3925 // This is a template variable, print the expanded template arguments.
3926 printTemplateArgumentList(
3927 OS, IV->getTemplateArgs().asArray(), Policy,
3928 IV->getSpecializedTemplate()->getTemplateParameters());
3929 }
3930 return true;
3931 }
3932 return false;
3933 }
3934
3935 private:
3936 const PrintingPolicy Policy;
3937 };
3938
3939 } // end anonymous namespace
3940
3941 std::pair<Expr *, std::string>
findFailedBooleanCondition(Expr * Cond)3942 Sema::findFailedBooleanCondition(Expr *Cond) {
3943 Cond = lookThroughRangesV3Condition(PP, Cond);
3944
3945 // Separate out all of the terms in a conjunction.
3946 SmallVector<Expr *, 4> Terms;
3947 collectConjunctionTerms(Cond, Terms);
3948
3949 // Determine which term failed.
3950 Expr *FailedCond = nullptr;
3951 for (Expr *Term : Terms) {
3952 Expr *TermAsWritten = Term->IgnoreParenImpCasts();
3953
3954 // Literals are uninteresting.
3955 if (isa<CXXBoolLiteralExpr>(TermAsWritten) ||
3956 isa<IntegerLiteral>(TermAsWritten))
3957 continue;
3958
3959 // The initialization of the parameter from the argument is
3960 // a constant-evaluated context.
3961 EnterExpressionEvaluationContext ConstantEvaluated(
3962 *this, Sema::ExpressionEvaluationContext::ConstantEvaluated);
3963
3964 bool Succeeded;
3965 if (Term->EvaluateAsBooleanCondition(Succeeded, Context) &&
3966 !Succeeded) {
3967 FailedCond = TermAsWritten;
3968 break;
3969 }
3970 }
3971 if (!FailedCond)
3972 FailedCond = Cond->IgnoreParenImpCasts();
3973
3974 std::string Description;
3975 {
3976 llvm::raw_string_ostream Out(Description);
3977 PrintingPolicy Policy = getPrintingPolicy();
3978 Policy.PrintCanonicalTypes = true;
3979 FailedBooleanConditionPrinterHelper Helper(Policy);
3980 FailedCond->printPretty(Out, &Helper, Policy, 0, "\n", nullptr);
3981 }
3982 return { FailedCond, Description };
3983 }
3984
CheckTemplateIdType(TemplateName Name,SourceLocation TemplateLoc,TemplateArgumentListInfo & TemplateArgs)3985 QualType Sema::CheckTemplateIdType(TemplateName Name,
3986 SourceLocation TemplateLoc,
3987 TemplateArgumentListInfo &TemplateArgs) {
3988 DependentTemplateName *DTN
3989 = Name.getUnderlying().getAsDependentTemplateName();
3990 if (DTN && DTN->isIdentifier())
3991 // When building a template-id where the template-name is dependent,
3992 // assume the template is a type template. Either our assumption is
3993 // correct, or the code is ill-formed and will be diagnosed when the
3994 // dependent name is substituted.
3995 return Context.getDependentTemplateSpecializationType(
3996 ElaboratedTypeKeyword::None, DTN->getQualifier(), DTN->getIdentifier(),
3997 TemplateArgs.arguments());
3998
3999 if (Name.getAsAssumedTemplateName() &&
4000 resolveAssumedTemplateNameAsType(/*Scope*/nullptr, Name, TemplateLoc))
4001 return QualType();
4002
4003 TemplateDecl *Template = Name.getAsTemplateDecl();
4004 if (!Template || isa<FunctionTemplateDecl>(Template) ||
4005 isa<VarTemplateDecl>(Template) || isa<ConceptDecl>(Template)) {
4006 // We might have a substituted template template parameter pack. If so,
4007 // build a template specialization type for it.
4008 if (Name.getAsSubstTemplateTemplateParmPack())
4009 return Context.getTemplateSpecializationType(Name,
4010 TemplateArgs.arguments());
4011
4012 Diag(TemplateLoc, diag::err_template_id_not_a_type)
4013 << Name;
4014 NoteAllFoundTemplates(Name);
4015 return QualType();
4016 }
4017
4018 // Check that the template argument list is well-formed for this
4019 // template.
4020 SmallVector<TemplateArgument, 4> SugaredConverted, CanonicalConverted;
4021 if (CheckTemplateArgumentList(Template, TemplateLoc, TemplateArgs, false,
4022 SugaredConverted, CanonicalConverted,
4023 /*UpdateArgsWithConversions=*/true))
4024 return QualType();
4025
4026 QualType CanonType;
4027
4028 if (TypeAliasTemplateDecl *AliasTemplate =
4029 dyn_cast<TypeAliasTemplateDecl>(Template)) {
4030
4031 // Find the canonical type for this type alias template specialization.
4032 TypeAliasDecl *Pattern = AliasTemplate->getTemplatedDecl();
4033 if (Pattern->isInvalidDecl())
4034 return QualType();
4035
4036 // Only substitute for the innermost template argument list.
4037 MultiLevelTemplateArgumentList TemplateArgLists;
4038 TemplateArgLists.addOuterTemplateArguments(Template, CanonicalConverted,
4039 /*Final=*/false);
4040 TemplateArgLists.addOuterRetainedLevels(
4041 AliasTemplate->getTemplateParameters()->getDepth());
4042
4043 LocalInstantiationScope Scope(*this);
4044 InstantiatingTemplate Inst(*this, TemplateLoc, Template);
4045 if (Inst.isInvalid())
4046 return QualType();
4047
4048 CanonType = SubstType(Pattern->getUnderlyingType(),
4049 TemplateArgLists, AliasTemplate->getLocation(),
4050 AliasTemplate->getDeclName());
4051 if (CanonType.isNull()) {
4052 // If this was enable_if and we failed to find the nested type
4053 // within enable_if in a SFINAE context, dig out the specific
4054 // enable_if condition that failed and present that instead.
4055 if (isEnableIfAliasTemplate(AliasTemplate)) {
4056 if (auto DeductionInfo = isSFINAEContext()) {
4057 if (*DeductionInfo &&
4058 (*DeductionInfo)->hasSFINAEDiagnostic() &&
4059 (*DeductionInfo)->peekSFINAEDiagnostic().second.getDiagID() ==
4060 diag::err_typename_nested_not_found_enable_if &&
4061 TemplateArgs[0].getArgument().getKind()
4062 == TemplateArgument::Expression) {
4063 Expr *FailedCond;
4064 std::string FailedDescription;
4065 std::tie(FailedCond, FailedDescription) =
4066 findFailedBooleanCondition(TemplateArgs[0].getSourceExpression());
4067
4068 // Remove the old SFINAE diagnostic.
4069 PartialDiagnosticAt OldDiag =
4070 {SourceLocation(), PartialDiagnostic::NullDiagnostic()};
4071 (*DeductionInfo)->takeSFINAEDiagnostic(OldDiag);
4072
4073 // Add a new SFINAE diagnostic specifying which condition
4074 // failed.
4075 (*DeductionInfo)->addSFINAEDiagnostic(
4076 OldDiag.first,
4077 PDiag(diag::err_typename_nested_not_found_requirement)
4078 << FailedDescription
4079 << FailedCond->getSourceRange());
4080 }
4081 }
4082 }
4083
4084 return QualType();
4085 }
4086 } else if (auto *BTD = dyn_cast<BuiltinTemplateDecl>(Template)) {
4087 CanonType = checkBuiltinTemplateIdType(*this, BTD, SugaredConverted,
4088 TemplateLoc, TemplateArgs);
4089 } else if (Name.isDependent() ||
4090 TemplateSpecializationType::anyDependentTemplateArguments(
4091 TemplateArgs, CanonicalConverted)) {
4092 // This class template specialization is a dependent
4093 // type. Therefore, its canonical type is another class template
4094 // specialization type that contains all of the converted
4095 // arguments in canonical form. This ensures that, e.g., A<T> and
4096 // A<T, T> have identical types when A is declared as:
4097 //
4098 // template<typename T, typename U = T> struct A;
4099 CanonType = Context.getCanonicalTemplateSpecializationType(
4100 Name, CanonicalConverted);
4101
4102 // This might work out to be a current instantiation, in which
4103 // case the canonical type needs to be the InjectedClassNameType.
4104 //
4105 // TODO: in theory this could be a simple hashtable lookup; most
4106 // changes to CurContext don't change the set of current
4107 // instantiations.
4108 if (isa<ClassTemplateDecl>(Template)) {
4109 for (DeclContext *Ctx = CurContext; Ctx; Ctx = Ctx->getLookupParent()) {
4110 // If we get out to a namespace, we're done.
4111 if (Ctx->isFileContext()) break;
4112
4113 // If this isn't a record, keep looking.
4114 CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(Ctx);
4115 if (!Record) continue;
4116
4117 // Look for one of the two cases with InjectedClassNameTypes
4118 // and check whether it's the same template.
4119 if (!isa<ClassTemplatePartialSpecializationDecl>(Record) &&
4120 !Record->getDescribedClassTemplate())
4121 continue;
4122
4123 // Fetch the injected class name type and check whether its
4124 // injected type is equal to the type we just built.
4125 QualType ICNT = Context.getTypeDeclType(Record);
4126 QualType Injected = cast<InjectedClassNameType>(ICNT)
4127 ->getInjectedSpecializationType();
4128
4129 if (CanonType != Injected->getCanonicalTypeInternal())
4130 continue;
4131
4132 // If so, the canonical type of this TST is the injected
4133 // class name type of the record we just found.
4134 assert(ICNT.isCanonical());
4135 CanonType = ICNT;
4136 break;
4137 }
4138 }
4139 } else if (ClassTemplateDecl *ClassTemplate =
4140 dyn_cast<ClassTemplateDecl>(Template)) {
4141 // Find the class template specialization declaration that
4142 // corresponds to these arguments.
4143 void *InsertPos = nullptr;
4144 ClassTemplateSpecializationDecl *Decl =
4145 ClassTemplate->findSpecialization(CanonicalConverted, InsertPos);
4146 if (!Decl) {
4147 // This is the first time we have referenced this class template
4148 // specialization. Create the canonical declaration and add it to
4149 // the set of specializations.
4150 Decl = ClassTemplateSpecializationDecl::Create(
4151 Context, ClassTemplate->getTemplatedDecl()->getTagKind(),
4152 ClassTemplate->getDeclContext(),
4153 ClassTemplate->getTemplatedDecl()->getBeginLoc(),
4154 ClassTemplate->getLocation(), ClassTemplate, CanonicalConverted,
4155 nullptr);
4156 ClassTemplate->AddSpecialization(Decl, InsertPos);
4157 if (ClassTemplate->isOutOfLine())
4158 Decl->setLexicalDeclContext(ClassTemplate->getLexicalDeclContext());
4159 }
4160
4161 if (Decl->getSpecializationKind() == TSK_Undeclared &&
4162 ClassTemplate->getTemplatedDecl()->hasAttrs()) {
4163 InstantiatingTemplate Inst(*this, TemplateLoc, Decl);
4164 if (!Inst.isInvalid()) {
4165 MultiLevelTemplateArgumentList TemplateArgLists(Template,
4166 CanonicalConverted,
4167 /*Final=*/false);
4168 InstantiateAttrsForDecl(TemplateArgLists,
4169 ClassTemplate->getTemplatedDecl(), Decl);
4170 }
4171 }
4172
4173 // Diagnose uses of this specialization.
4174 (void)DiagnoseUseOfDecl(Decl, TemplateLoc);
4175
4176 CanonType = Context.getTypeDeclType(Decl);
4177 assert(isa<RecordType>(CanonType) &&
4178 "type of non-dependent specialization is not a RecordType");
4179 } else {
4180 llvm_unreachable("Unhandled template kind");
4181 }
4182
4183 // Build the fully-sugared type for this class template
4184 // specialization, which refers back to the class template
4185 // specialization we created or found.
4186 return Context.getTemplateSpecializationType(Name, TemplateArgs.arguments(),
4187 CanonType);
4188 }
4189
ActOnUndeclaredTypeTemplateName(Scope * S,TemplateTy & ParsedName,TemplateNameKind & TNK,SourceLocation NameLoc,IdentifierInfo * & II)4190 void Sema::ActOnUndeclaredTypeTemplateName(Scope *S, TemplateTy &ParsedName,
4191 TemplateNameKind &TNK,
4192 SourceLocation NameLoc,
4193 IdentifierInfo *&II) {
4194 assert(TNK == TNK_Undeclared_template && "not an undeclared template name");
4195
4196 TemplateName Name = ParsedName.get();
4197 auto *ATN = Name.getAsAssumedTemplateName();
4198 assert(ATN && "not an assumed template name");
4199 II = ATN->getDeclName().getAsIdentifierInfo();
4200
4201 if (!resolveAssumedTemplateNameAsType(S, Name, NameLoc, /*Diagnose*/false)) {
4202 // Resolved to a type template name.
4203 ParsedName = TemplateTy::make(Name);
4204 TNK = TNK_Type_template;
4205 }
4206 }
4207
resolveAssumedTemplateNameAsType(Scope * S,TemplateName & Name,SourceLocation NameLoc,bool Diagnose)4208 bool Sema::resolveAssumedTemplateNameAsType(Scope *S, TemplateName &Name,
4209 SourceLocation NameLoc,
4210 bool Diagnose) {
4211 // We assumed this undeclared identifier to be an (ADL-only) function
4212 // template name, but it was used in a context where a type was required.
4213 // Try to typo-correct it now.
4214 AssumedTemplateStorage *ATN = Name.getAsAssumedTemplateName();
4215 assert(ATN && "not an assumed template name");
4216
4217 LookupResult R(*this, ATN->getDeclName(), NameLoc, LookupOrdinaryName);
4218 struct CandidateCallback : CorrectionCandidateCallback {
4219 bool ValidateCandidate(const TypoCorrection &TC) override {
4220 return TC.getCorrectionDecl() &&
4221 getAsTypeTemplateDecl(TC.getCorrectionDecl());
4222 }
4223 std::unique_ptr<CorrectionCandidateCallback> clone() override {
4224 return std::make_unique<CandidateCallback>(*this);
4225 }
4226 } FilterCCC;
4227
4228 TypoCorrection Corrected =
4229 CorrectTypo(R.getLookupNameInfo(), R.getLookupKind(), S, nullptr,
4230 FilterCCC, CTK_ErrorRecovery);
4231 if (Corrected && Corrected.getFoundDecl()) {
4232 diagnoseTypo(Corrected, PDiag(diag::err_no_template_suggest)
4233 << ATN->getDeclName());
4234 Name = TemplateName(Corrected.getCorrectionDeclAs<TemplateDecl>());
4235 return false;
4236 }
4237
4238 if (Diagnose)
4239 Diag(R.getNameLoc(), diag::err_no_template) << R.getLookupName();
4240 return true;
4241 }
4242
ActOnTemplateIdType(Scope * S,CXXScopeSpec & SS,SourceLocation TemplateKWLoc,TemplateTy TemplateD,IdentifierInfo * TemplateII,SourceLocation TemplateIILoc,SourceLocation LAngleLoc,ASTTemplateArgsPtr TemplateArgsIn,SourceLocation RAngleLoc,bool IsCtorOrDtorName,bool IsClassName,ImplicitTypenameContext AllowImplicitTypename)4243 TypeResult Sema::ActOnTemplateIdType(
4244 Scope *S, CXXScopeSpec &SS, SourceLocation TemplateKWLoc,
4245 TemplateTy TemplateD, IdentifierInfo *TemplateII,
4246 SourceLocation TemplateIILoc, SourceLocation LAngleLoc,
4247 ASTTemplateArgsPtr TemplateArgsIn, SourceLocation RAngleLoc,
4248 bool IsCtorOrDtorName, bool IsClassName,
4249 ImplicitTypenameContext AllowImplicitTypename) {
4250 if (SS.isInvalid())
4251 return true;
4252
4253 if (!IsCtorOrDtorName && !IsClassName && SS.isSet()) {
4254 DeclContext *LookupCtx = computeDeclContext(SS, /*EnteringContext*/false);
4255
4256 // C++ [temp.res]p3:
4257 // A qualified-id that refers to a type and in which the
4258 // nested-name-specifier depends on a template-parameter (14.6.2)
4259 // shall be prefixed by the keyword typename to indicate that the
4260 // qualified-id denotes a type, forming an
4261 // elaborated-type-specifier (7.1.5.3).
4262 if (!LookupCtx && isDependentScopeSpecifier(SS)) {
4263 // C++2a relaxes some of those restrictions in [temp.res]p5.
4264 if (AllowImplicitTypename == ImplicitTypenameContext::Yes) {
4265 if (getLangOpts().CPlusPlus20)
4266 Diag(SS.getBeginLoc(), diag::warn_cxx17_compat_implicit_typename);
4267 else
4268 Diag(SS.getBeginLoc(), diag::ext_implicit_typename)
4269 << SS.getScopeRep() << TemplateII->getName()
4270 << FixItHint::CreateInsertion(SS.getBeginLoc(), "typename ");
4271 } else
4272 Diag(SS.getBeginLoc(), diag::err_typename_missing_template)
4273 << SS.getScopeRep() << TemplateII->getName();
4274
4275 // FIXME: This is not quite correct recovery as we don't transform SS
4276 // into the corresponding dependent form (and we don't diagnose missing
4277 // 'template' keywords within SS as a result).
4278 return ActOnTypenameType(nullptr, SourceLocation(), SS, TemplateKWLoc,
4279 TemplateD, TemplateII, TemplateIILoc, LAngleLoc,
4280 TemplateArgsIn, RAngleLoc);
4281 }
4282
4283 // Per C++ [class.qual]p2, if the template-id was an injected-class-name,
4284 // it's not actually allowed to be used as a type in most cases. Because
4285 // we annotate it before we know whether it's valid, we have to check for
4286 // this case here.
4287 auto *LookupRD = dyn_cast_or_null<CXXRecordDecl>(LookupCtx);
4288 if (LookupRD && LookupRD->getIdentifier() == TemplateII) {
4289 Diag(TemplateIILoc,
4290 TemplateKWLoc.isInvalid()
4291 ? diag::err_out_of_line_qualified_id_type_names_constructor
4292 : diag::ext_out_of_line_qualified_id_type_names_constructor)
4293 << TemplateII << 0 /*injected-class-name used as template name*/
4294 << 1 /*if any keyword was present, it was 'template'*/;
4295 }
4296 }
4297
4298 TemplateName Template = TemplateD.get();
4299 if (Template.getAsAssumedTemplateName() &&
4300 resolveAssumedTemplateNameAsType(S, Template, TemplateIILoc))
4301 return true;
4302
4303 // Translate the parser's template argument list in our AST format.
4304 TemplateArgumentListInfo TemplateArgs(LAngleLoc, RAngleLoc);
4305 translateTemplateArguments(TemplateArgsIn, TemplateArgs);
4306
4307 if (DependentTemplateName *DTN = Template.getAsDependentTemplateName()) {
4308 assert(SS.getScopeRep() == DTN->getQualifier());
4309 QualType T = Context.getDependentTemplateSpecializationType(
4310 ElaboratedTypeKeyword::None, DTN->getQualifier(), DTN->getIdentifier(),
4311 TemplateArgs.arguments());
4312 // Build type-source information.
4313 TypeLocBuilder TLB;
4314 DependentTemplateSpecializationTypeLoc SpecTL
4315 = TLB.push<DependentTemplateSpecializationTypeLoc>(T);
4316 SpecTL.setElaboratedKeywordLoc(SourceLocation());
4317 SpecTL.setQualifierLoc(SS.getWithLocInContext(Context));
4318 SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
4319 SpecTL.setTemplateNameLoc(TemplateIILoc);
4320 SpecTL.setLAngleLoc(LAngleLoc);
4321 SpecTL.setRAngleLoc(RAngleLoc);
4322 for (unsigned I = 0, N = SpecTL.getNumArgs(); I != N; ++I)
4323 SpecTL.setArgLocInfo(I, TemplateArgs[I].getLocInfo());
4324 return CreateParsedType(T, TLB.getTypeSourceInfo(Context, T));
4325 }
4326
4327 QualType SpecTy = CheckTemplateIdType(Template, TemplateIILoc, TemplateArgs);
4328 if (SpecTy.isNull())
4329 return true;
4330
4331 // Build type-source information.
4332 TypeLocBuilder TLB;
4333 TemplateSpecializationTypeLoc SpecTL =
4334 TLB.push<TemplateSpecializationTypeLoc>(SpecTy);
4335 SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
4336 SpecTL.setTemplateNameLoc(TemplateIILoc);
4337 SpecTL.setLAngleLoc(LAngleLoc);
4338 SpecTL.setRAngleLoc(RAngleLoc);
4339 for (unsigned i = 0, e = SpecTL.getNumArgs(); i != e; ++i)
4340 SpecTL.setArgLocInfo(i, TemplateArgs[i].getLocInfo());
4341
4342 // Create an elaborated-type-specifier containing the nested-name-specifier.
4343 QualType ElTy =
4344 getElaboratedType(ElaboratedTypeKeyword::None,
4345 !IsCtorOrDtorName ? SS : CXXScopeSpec(), SpecTy);
4346 ElaboratedTypeLoc ElabTL = TLB.push<ElaboratedTypeLoc>(ElTy);
4347 ElabTL.setElaboratedKeywordLoc(SourceLocation());
4348 if (!ElabTL.isEmpty())
4349 ElabTL.setQualifierLoc(SS.getWithLocInContext(Context));
4350 return CreateParsedType(ElTy, TLB.getTypeSourceInfo(Context, ElTy));
4351 }
4352
ActOnTagTemplateIdType(TagUseKind TUK,TypeSpecifierType TagSpec,SourceLocation TagLoc,CXXScopeSpec & SS,SourceLocation TemplateKWLoc,TemplateTy TemplateD,SourceLocation TemplateLoc,SourceLocation LAngleLoc,ASTTemplateArgsPtr TemplateArgsIn,SourceLocation RAngleLoc)4353 TypeResult Sema::ActOnTagTemplateIdType(TagUseKind TUK,
4354 TypeSpecifierType TagSpec,
4355 SourceLocation TagLoc,
4356 CXXScopeSpec &SS,
4357 SourceLocation TemplateKWLoc,
4358 TemplateTy TemplateD,
4359 SourceLocation TemplateLoc,
4360 SourceLocation LAngleLoc,
4361 ASTTemplateArgsPtr TemplateArgsIn,
4362 SourceLocation RAngleLoc) {
4363 if (SS.isInvalid())
4364 return TypeResult(true);
4365
4366 TemplateName Template = TemplateD.get();
4367
4368 // Translate the parser's template argument list in our AST format.
4369 TemplateArgumentListInfo TemplateArgs(LAngleLoc, RAngleLoc);
4370 translateTemplateArguments(TemplateArgsIn, TemplateArgs);
4371
4372 // Determine the tag kind
4373 TagTypeKind TagKind = TypeWithKeyword::getTagTypeKindForTypeSpec(TagSpec);
4374 ElaboratedTypeKeyword Keyword
4375 = TypeWithKeyword::getKeywordForTagTypeKind(TagKind);
4376
4377 if (DependentTemplateName *DTN = Template.getAsDependentTemplateName()) {
4378 assert(SS.getScopeRep() == DTN->getQualifier());
4379 QualType T = Context.getDependentTemplateSpecializationType(
4380 Keyword, DTN->getQualifier(), DTN->getIdentifier(),
4381 TemplateArgs.arguments());
4382
4383 // Build type-source information.
4384 TypeLocBuilder TLB;
4385 DependentTemplateSpecializationTypeLoc SpecTL
4386 = TLB.push<DependentTemplateSpecializationTypeLoc>(T);
4387 SpecTL.setElaboratedKeywordLoc(TagLoc);
4388 SpecTL.setQualifierLoc(SS.getWithLocInContext(Context));
4389 SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
4390 SpecTL.setTemplateNameLoc(TemplateLoc);
4391 SpecTL.setLAngleLoc(LAngleLoc);
4392 SpecTL.setRAngleLoc(RAngleLoc);
4393 for (unsigned I = 0, N = SpecTL.getNumArgs(); I != N; ++I)
4394 SpecTL.setArgLocInfo(I, TemplateArgs[I].getLocInfo());
4395 return CreateParsedType(T, TLB.getTypeSourceInfo(Context, T));
4396 }
4397
4398 if (TypeAliasTemplateDecl *TAT =
4399 dyn_cast_or_null<TypeAliasTemplateDecl>(Template.getAsTemplateDecl())) {
4400 // C++0x [dcl.type.elab]p2:
4401 // If the identifier resolves to a typedef-name or the simple-template-id
4402 // resolves to an alias template specialization, the
4403 // elaborated-type-specifier is ill-formed.
4404 Diag(TemplateLoc, diag::err_tag_reference_non_tag)
4405 << TAT << NTK_TypeAliasTemplate << llvm::to_underlying(TagKind);
4406 Diag(TAT->getLocation(), diag::note_declared_at);
4407 }
4408
4409 QualType Result = CheckTemplateIdType(Template, TemplateLoc, TemplateArgs);
4410 if (Result.isNull())
4411 return TypeResult(true);
4412
4413 // Check the tag kind
4414 if (const RecordType *RT = Result->getAs<RecordType>()) {
4415 RecordDecl *D = RT->getDecl();
4416
4417 IdentifierInfo *Id = D->getIdentifier();
4418 assert(Id && "templated class must have an identifier");
4419
4420 if (!isAcceptableTagRedeclaration(D, TagKind, TUK == TUK_Definition,
4421 TagLoc, Id)) {
4422 Diag(TagLoc, diag::err_use_with_wrong_tag)
4423 << Result
4424 << FixItHint::CreateReplacement(SourceRange(TagLoc), D->getKindName());
4425 Diag(D->getLocation(), diag::note_previous_use);
4426 }
4427 }
4428
4429 // Provide source-location information for the template specialization.
4430 TypeLocBuilder TLB;
4431 TemplateSpecializationTypeLoc SpecTL
4432 = TLB.push<TemplateSpecializationTypeLoc>(Result);
4433 SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
4434 SpecTL.setTemplateNameLoc(TemplateLoc);
4435 SpecTL.setLAngleLoc(LAngleLoc);
4436 SpecTL.setRAngleLoc(RAngleLoc);
4437 for (unsigned i = 0, e = SpecTL.getNumArgs(); i != e; ++i)
4438 SpecTL.setArgLocInfo(i, TemplateArgs[i].getLocInfo());
4439
4440 // Construct an elaborated type containing the nested-name-specifier (if any)
4441 // and tag keyword.
4442 Result = Context.getElaboratedType(Keyword, SS.getScopeRep(), Result);
4443 ElaboratedTypeLoc ElabTL = TLB.push<ElaboratedTypeLoc>(Result);
4444 ElabTL.setElaboratedKeywordLoc(TagLoc);
4445 ElabTL.setQualifierLoc(SS.getWithLocInContext(Context));
4446 return CreateParsedType(Result, TLB.getTypeSourceInfo(Context, Result));
4447 }
4448
4449 static bool CheckTemplateSpecializationScope(Sema &S, NamedDecl *Specialized,
4450 NamedDecl *PrevDecl,
4451 SourceLocation Loc,
4452 bool IsPartialSpecialization);
4453
4454 static TemplateSpecializationKind getTemplateSpecializationKind(Decl *D);
4455
isTemplateArgumentTemplateParameter(const TemplateArgument & Arg,unsigned Depth,unsigned Index)4456 static bool isTemplateArgumentTemplateParameter(
4457 const TemplateArgument &Arg, unsigned Depth, unsigned Index) {
4458 switch (Arg.getKind()) {
4459 case TemplateArgument::Null:
4460 case TemplateArgument::NullPtr:
4461 case TemplateArgument::Integral:
4462 case TemplateArgument::Declaration:
4463 case TemplateArgument::StructuralValue:
4464 case TemplateArgument::Pack:
4465 case TemplateArgument::TemplateExpansion:
4466 return false;
4467
4468 case TemplateArgument::Type: {
4469 QualType Type = Arg.getAsType();
4470 const TemplateTypeParmType *TPT =
4471 Arg.getAsType()->getAs<TemplateTypeParmType>();
4472 return TPT && !Type.hasQualifiers() &&
4473 TPT->getDepth() == Depth && TPT->getIndex() == Index;
4474 }
4475
4476 case TemplateArgument::Expression: {
4477 DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Arg.getAsExpr());
4478 if (!DRE || !DRE->getDecl())
4479 return false;
4480 const NonTypeTemplateParmDecl *NTTP =
4481 dyn_cast<NonTypeTemplateParmDecl>(DRE->getDecl());
4482 return NTTP && NTTP->getDepth() == Depth && NTTP->getIndex() == Index;
4483 }
4484
4485 case TemplateArgument::Template:
4486 const TemplateTemplateParmDecl *TTP =
4487 dyn_cast_or_null<TemplateTemplateParmDecl>(
4488 Arg.getAsTemplateOrTemplatePattern().getAsTemplateDecl());
4489 return TTP && TTP->getDepth() == Depth && TTP->getIndex() == Index;
4490 }
4491 llvm_unreachable("unexpected kind of template argument");
4492 }
4493
isSameAsPrimaryTemplate(TemplateParameterList * Params,ArrayRef<TemplateArgument> Args)4494 static bool isSameAsPrimaryTemplate(TemplateParameterList *Params,
4495 ArrayRef<TemplateArgument> Args) {
4496 if (Params->size() != Args.size())
4497 return false;
4498
4499 unsigned Depth = Params->getDepth();
4500
4501 for (unsigned I = 0, N = Args.size(); I != N; ++I) {
4502 TemplateArgument Arg = Args[I];
4503
4504 // If the parameter is a pack expansion, the argument must be a pack
4505 // whose only element is a pack expansion.
4506 if (Params->getParam(I)->isParameterPack()) {
4507 if (Arg.getKind() != TemplateArgument::Pack || Arg.pack_size() != 1 ||
4508 !Arg.pack_begin()->isPackExpansion())
4509 return false;
4510 Arg = Arg.pack_begin()->getPackExpansionPattern();
4511 }
4512
4513 if (!isTemplateArgumentTemplateParameter(Arg, Depth, I))
4514 return false;
4515 }
4516
4517 return true;
4518 }
4519
4520 template<typename PartialSpecDecl>
checkMoreSpecializedThanPrimary(Sema & S,PartialSpecDecl * Partial)4521 static void checkMoreSpecializedThanPrimary(Sema &S, PartialSpecDecl *Partial) {
4522 if (Partial->getDeclContext()->isDependentContext())
4523 return;
4524
4525 // FIXME: Get the TDK from deduction in order to provide better diagnostics
4526 // for non-substitution-failure issues?
4527 TemplateDeductionInfo Info(Partial->getLocation());
4528 if (S.isMoreSpecializedThanPrimary(Partial, Info))
4529 return;
4530
4531 auto *Template = Partial->getSpecializedTemplate();
4532 S.Diag(Partial->getLocation(),
4533 diag::ext_partial_spec_not_more_specialized_than_primary)
4534 << isa<VarTemplateDecl>(Template);
4535
4536 if (Info.hasSFINAEDiagnostic()) {
4537 PartialDiagnosticAt Diag = {SourceLocation(),
4538 PartialDiagnostic::NullDiagnostic()};
4539 Info.takeSFINAEDiagnostic(Diag);
4540 SmallString<128> SFINAEArgString;
4541 Diag.second.EmitToString(S.getDiagnostics(), SFINAEArgString);
4542 S.Diag(Diag.first,
4543 diag::note_partial_spec_not_more_specialized_than_primary)
4544 << SFINAEArgString;
4545 }
4546
4547 S.NoteTemplateLocation(*Template);
4548 SmallVector<const Expr *, 3> PartialAC, TemplateAC;
4549 Template->getAssociatedConstraints(TemplateAC);
4550 Partial->getAssociatedConstraints(PartialAC);
4551 S.MaybeEmitAmbiguousAtomicConstraintsDiagnostic(Partial, PartialAC, Template,
4552 TemplateAC);
4553 }
4554
4555 static void
noteNonDeducibleParameters(Sema & S,TemplateParameterList * TemplateParams,const llvm::SmallBitVector & DeducibleParams)4556 noteNonDeducibleParameters(Sema &S, TemplateParameterList *TemplateParams,
4557 const llvm::SmallBitVector &DeducibleParams) {
4558 for (unsigned I = 0, N = DeducibleParams.size(); I != N; ++I) {
4559 if (!DeducibleParams[I]) {
4560 NamedDecl *Param = TemplateParams->getParam(I);
4561 if (Param->getDeclName())
4562 S.Diag(Param->getLocation(), diag::note_non_deducible_parameter)
4563 << Param->getDeclName();
4564 else
4565 S.Diag(Param->getLocation(), diag::note_non_deducible_parameter)
4566 << "(anonymous)";
4567 }
4568 }
4569 }
4570
4571
4572 template<typename PartialSpecDecl>
checkTemplatePartialSpecialization(Sema & S,PartialSpecDecl * Partial)4573 static void checkTemplatePartialSpecialization(Sema &S,
4574 PartialSpecDecl *Partial) {
4575 // C++1z [temp.class.spec]p8: (DR1495)
4576 // - The specialization shall be more specialized than the primary
4577 // template (14.5.5.2).
4578 checkMoreSpecializedThanPrimary(S, Partial);
4579
4580 // C++ [temp.class.spec]p8: (DR1315)
4581 // - Each template-parameter shall appear at least once in the
4582 // template-id outside a non-deduced context.
4583 // C++1z [temp.class.spec.match]p3 (P0127R2)
4584 // If the template arguments of a partial specialization cannot be
4585 // deduced because of the structure of its template-parameter-list
4586 // and the template-id, the program is ill-formed.
4587 auto *TemplateParams = Partial->getTemplateParameters();
4588 llvm::SmallBitVector DeducibleParams(TemplateParams->size());
4589 S.MarkUsedTemplateParameters(Partial->getTemplateArgs(), true,
4590 TemplateParams->getDepth(), DeducibleParams);
4591
4592 if (!DeducibleParams.all()) {
4593 unsigned NumNonDeducible = DeducibleParams.size() - DeducibleParams.count();
4594 S.Diag(Partial->getLocation(), diag::ext_partial_specs_not_deducible)
4595 << isa<VarTemplatePartialSpecializationDecl>(Partial)
4596 << (NumNonDeducible > 1)
4597 << SourceRange(Partial->getLocation(),
4598 Partial->getTemplateArgsAsWritten()->RAngleLoc);
4599 noteNonDeducibleParameters(S, TemplateParams, DeducibleParams);
4600 }
4601 }
4602
CheckTemplatePartialSpecialization(ClassTemplatePartialSpecializationDecl * Partial)4603 void Sema::CheckTemplatePartialSpecialization(
4604 ClassTemplatePartialSpecializationDecl *Partial) {
4605 checkTemplatePartialSpecialization(*this, Partial);
4606 }
4607
CheckTemplatePartialSpecialization(VarTemplatePartialSpecializationDecl * Partial)4608 void Sema::CheckTemplatePartialSpecialization(
4609 VarTemplatePartialSpecializationDecl *Partial) {
4610 checkTemplatePartialSpecialization(*this, Partial);
4611 }
4612
CheckDeductionGuideTemplate(FunctionTemplateDecl * TD)4613 void Sema::CheckDeductionGuideTemplate(FunctionTemplateDecl *TD) {
4614 // C++1z [temp.param]p11:
4615 // A template parameter of a deduction guide template that does not have a
4616 // default-argument shall be deducible from the parameter-type-list of the
4617 // deduction guide template.
4618 auto *TemplateParams = TD->getTemplateParameters();
4619 llvm::SmallBitVector DeducibleParams(TemplateParams->size());
4620 MarkDeducedTemplateParameters(TD, DeducibleParams);
4621 for (unsigned I = 0; I != TemplateParams->size(); ++I) {
4622 // A parameter pack is deducible (to an empty pack).
4623 auto *Param = TemplateParams->getParam(I);
4624 if (Param->isParameterPack() || hasVisibleDefaultArgument(Param))
4625 DeducibleParams[I] = true;
4626 }
4627
4628 if (!DeducibleParams.all()) {
4629 unsigned NumNonDeducible = DeducibleParams.size() - DeducibleParams.count();
4630 Diag(TD->getLocation(), diag::err_deduction_guide_template_not_deducible)
4631 << (NumNonDeducible > 1);
4632 noteNonDeducibleParameters(*this, TemplateParams, DeducibleParams);
4633 }
4634 }
4635
ActOnVarTemplateSpecialization(Scope * S,Declarator & D,TypeSourceInfo * DI,SourceLocation TemplateKWLoc,TemplateParameterList * TemplateParams,StorageClass SC,bool IsPartialSpecialization)4636 DeclResult Sema::ActOnVarTemplateSpecialization(
4637 Scope *S, Declarator &D, TypeSourceInfo *DI, SourceLocation TemplateKWLoc,
4638 TemplateParameterList *TemplateParams, StorageClass SC,
4639 bool IsPartialSpecialization) {
4640 // D must be variable template id.
4641 assert(D.getName().getKind() == UnqualifiedIdKind::IK_TemplateId &&
4642 "Variable template specialization is declared with a template id.");
4643
4644 TemplateIdAnnotation *TemplateId = D.getName().TemplateId;
4645 TemplateArgumentListInfo TemplateArgs =
4646 makeTemplateArgumentListInfo(*this, *TemplateId);
4647 SourceLocation TemplateNameLoc = D.getIdentifierLoc();
4648 SourceLocation LAngleLoc = TemplateId->LAngleLoc;
4649 SourceLocation RAngleLoc = TemplateId->RAngleLoc;
4650
4651 TemplateName Name = TemplateId->Template.get();
4652
4653 // The template-id must name a variable template.
4654 VarTemplateDecl *VarTemplate =
4655 dyn_cast_or_null<VarTemplateDecl>(Name.getAsTemplateDecl());
4656 if (!VarTemplate) {
4657 NamedDecl *FnTemplate;
4658 if (auto *OTS = Name.getAsOverloadedTemplate())
4659 FnTemplate = *OTS->begin();
4660 else
4661 FnTemplate = dyn_cast_or_null<FunctionTemplateDecl>(Name.getAsTemplateDecl());
4662 if (FnTemplate)
4663 return Diag(D.getIdentifierLoc(), diag::err_var_spec_no_template_but_method)
4664 << FnTemplate->getDeclName();
4665 return Diag(D.getIdentifierLoc(), diag::err_var_spec_no_template)
4666 << IsPartialSpecialization;
4667 }
4668
4669 // Check for unexpanded parameter packs in any of the template arguments.
4670 for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I)
4671 if (DiagnoseUnexpandedParameterPack(TemplateArgs[I],
4672 IsPartialSpecialization
4673 ? UPPC_PartialSpecialization
4674 : UPPC_ExplicitSpecialization))
4675 return true;
4676
4677 // Check that the template argument list is well-formed for this
4678 // template.
4679 SmallVector<TemplateArgument, 4> SugaredConverted, CanonicalConverted;
4680 if (CheckTemplateArgumentList(VarTemplate, TemplateNameLoc, TemplateArgs,
4681 false, SugaredConverted, CanonicalConverted,
4682 /*UpdateArgsWithConversions=*/true))
4683 return true;
4684
4685 // Find the variable template (partial) specialization declaration that
4686 // corresponds to these arguments.
4687 if (IsPartialSpecialization) {
4688 if (CheckTemplatePartialSpecializationArgs(TemplateNameLoc, VarTemplate,
4689 TemplateArgs.size(),
4690 CanonicalConverted))
4691 return true;
4692
4693 // FIXME: Move these checks to CheckTemplatePartialSpecializationArgs so we
4694 // also do them during instantiation.
4695 if (!Name.isDependent() &&
4696 !TemplateSpecializationType::anyDependentTemplateArguments(
4697 TemplateArgs, CanonicalConverted)) {
4698 Diag(TemplateNameLoc, diag::err_partial_spec_fully_specialized)
4699 << VarTemplate->getDeclName();
4700 IsPartialSpecialization = false;
4701 }
4702
4703 if (isSameAsPrimaryTemplate(VarTemplate->getTemplateParameters(),
4704 CanonicalConverted) &&
4705 (!Context.getLangOpts().CPlusPlus20 ||
4706 !TemplateParams->hasAssociatedConstraints())) {
4707 // C++ [temp.class.spec]p9b3:
4708 //
4709 // -- The argument list of the specialization shall not be identical
4710 // to the implicit argument list of the primary template.
4711 Diag(TemplateNameLoc, diag::err_partial_spec_args_match_primary_template)
4712 << /*variable template*/ 1
4713 << /*is definition*/(SC != SC_Extern && !CurContext->isRecord())
4714 << FixItHint::CreateRemoval(SourceRange(LAngleLoc, RAngleLoc));
4715 // FIXME: Recover from this by treating the declaration as a redeclaration
4716 // of the primary template.
4717 return true;
4718 }
4719 }
4720
4721 void *InsertPos = nullptr;
4722 VarTemplateSpecializationDecl *PrevDecl = nullptr;
4723
4724 if (IsPartialSpecialization)
4725 PrevDecl = VarTemplate->findPartialSpecialization(
4726 CanonicalConverted, TemplateParams, InsertPos);
4727 else
4728 PrevDecl = VarTemplate->findSpecialization(CanonicalConverted, InsertPos);
4729
4730 VarTemplateSpecializationDecl *Specialization = nullptr;
4731
4732 // Check whether we can declare a variable template specialization in
4733 // the current scope.
4734 if (CheckTemplateSpecializationScope(*this, VarTemplate, PrevDecl,
4735 TemplateNameLoc,
4736 IsPartialSpecialization))
4737 return true;
4738
4739 if (PrevDecl && PrevDecl->getSpecializationKind() == TSK_Undeclared) {
4740 // Since the only prior variable template specialization with these
4741 // arguments was referenced but not declared, reuse that
4742 // declaration node as our own, updating its source location and
4743 // the list of outer template parameters to reflect our new declaration.
4744 Specialization = PrevDecl;
4745 Specialization->setLocation(TemplateNameLoc);
4746 PrevDecl = nullptr;
4747 } else if (IsPartialSpecialization) {
4748 // Create a new class template partial specialization declaration node.
4749 VarTemplatePartialSpecializationDecl *PrevPartial =
4750 cast_or_null<VarTemplatePartialSpecializationDecl>(PrevDecl);
4751 VarTemplatePartialSpecializationDecl *Partial =
4752 VarTemplatePartialSpecializationDecl::Create(
4753 Context, VarTemplate->getDeclContext(), TemplateKWLoc,
4754 TemplateNameLoc, TemplateParams, VarTemplate, DI->getType(), DI, SC,
4755 CanonicalConverted, TemplateArgs);
4756
4757 if (!PrevPartial)
4758 VarTemplate->AddPartialSpecialization(Partial, InsertPos);
4759 Specialization = Partial;
4760
4761 // If we are providing an explicit specialization of a member variable
4762 // template specialization, make a note of that.
4763 if (PrevPartial && PrevPartial->getInstantiatedFromMember())
4764 PrevPartial->setMemberSpecialization();
4765
4766 CheckTemplatePartialSpecialization(Partial);
4767 } else {
4768 // Create a new class template specialization declaration node for
4769 // this explicit specialization or friend declaration.
4770 Specialization = VarTemplateSpecializationDecl::Create(
4771 Context, VarTemplate->getDeclContext(), TemplateKWLoc, TemplateNameLoc,
4772 VarTemplate, DI->getType(), DI, SC, CanonicalConverted);
4773 Specialization->setTemplateArgsInfo(TemplateArgs);
4774
4775 if (!PrevDecl)
4776 VarTemplate->AddSpecialization(Specialization, InsertPos);
4777 }
4778
4779 // C++ [temp.expl.spec]p6:
4780 // If a template, a member template or the member of a class template is
4781 // explicitly specialized then that specialization shall be declared
4782 // before the first use of that specialization that would cause an implicit
4783 // instantiation to take place, in every translation unit in which such a
4784 // use occurs; no diagnostic is required.
4785 if (PrevDecl && PrevDecl->getPointOfInstantiation().isValid()) {
4786 bool Okay = false;
4787 for (Decl *Prev = PrevDecl; Prev; Prev = Prev->getPreviousDecl()) {
4788 // Is there any previous explicit specialization declaration?
4789 if (getTemplateSpecializationKind(Prev) == TSK_ExplicitSpecialization) {
4790 Okay = true;
4791 break;
4792 }
4793 }
4794
4795 if (!Okay) {
4796 SourceRange Range(TemplateNameLoc, RAngleLoc);
4797 Diag(TemplateNameLoc, diag::err_specialization_after_instantiation)
4798 << Name << Range;
4799
4800 Diag(PrevDecl->getPointOfInstantiation(),
4801 diag::note_instantiation_required_here)
4802 << (PrevDecl->getTemplateSpecializationKind() !=
4803 TSK_ImplicitInstantiation);
4804 return true;
4805 }
4806 }
4807
4808 Specialization->setTemplateKeywordLoc(TemplateKWLoc);
4809 Specialization->setLexicalDeclContext(CurContext);
4810
4811 // Add the specialization into its lexical context, so that it can
4812 // be seen when iterating through the list of declarations in that
4813 // context. However, specializations are not found by name lookup.
4814 CurContext->addDecl(Specialization);
4815
4816 // Note that this is an explicit specialization.
4817 Specialization->setSpecializationKind(TSK_ExplicitSpecialization);
4818
4819 if (PrevDecl) {
4820 // Check that this isn't a redefinition of this specialization,
4821 // merging with previous declarations.
4822 LookupResult PrevSpec(*this, GetNameForDeclarator(D), LookupOrdinaryName,
4823 forRedeclarationInCurContext());
4824 PrevSpec.addDecl(PrevDecl);
4825 D.setRedeclaration(CheckVariableDeclaration(Specialization, PrevSpec));
4826 } else if (Specialization->isStaticDataMember() &&
4827 Specialization->isOutOfLine()) {
4828 Specialization->setAccess(VarTemplate->getAccess());
4829 }
4830
4831 return Specialization;
4832 }
4833
4834 namespace {
4835 /// A partial specialization whose template arguments have matched
4836 /// a given template-id.
4837 struct PartialSpecMatchResult {
4838 VarTemplatePartialSpecializationDecl *Partial;
4839 TemplateArgumentList *Args;
4840 };
4841 } // end anonymous namespace
4842
4843 DeclResult
CheckVarTemplateId(VarTemplateDecl * Template,SourceLocation TemplateLoc,SourceLocation TemplateNameLoc,const TemplateArgumentListInfo & TemplateArgs)4844 Sema::CheckVarTemplateId(VarTemplateDecl *Template, SourceLocation TemplateLoc,
4845 SourceLocation TemplateNameLoc,
4846 const TemplateArgumentListInfo &TemplateArgs) {
4847 assert(Template && "A variable template id without template?");
4848
4849 // Check that the template argument list is well-formed for this template.
4850 SmallVector<TemplateArgument, 4> SugaredConverted, CanonicalConverted;
4851 if (CheckTemplateArgumentList(
4852 Template, TemplateNameLoc,
4853 const_cast<TemplateArgumentListInfo &>(TemplateArgs), false,
4854 SugaredConverted, CanonicalConverted,
4855 /*UpdateArgsWithConversions=*/true))
4856 return true;
4857
4858 // Produce a placeholder value if the specialization is dependent.
4859 if (Template->getDeclContext()->isDependentContext() ||
4860 TemplateSpecializationType::anyDependentTemplateArguments(
4861 TemplateArgs, CanonicalConverted))
4862 return DeclResult();
4863
4864 // Find the variable template specialization declaration that
4865 // corresponds to these arguments.
4866 void *InsertPos = nullptr;
4867 if (VarTemplateSpecializationDecl *Spec =
4868 Template->findSpecialization(CanonicalConverted, InsertPos)) {
4869 checkSpecializationReachability(TemplateNameLoc, Spec);
4870 // If we already have a variable template specialization, return it.
4871 return Spec;
4872 }
4873
4874 // This is the first time we have referenced this variable template
4875 // specialization. Create the canonical declaration and add it to
4876 // the set of specializations, based on the closest partial specialization
4877 // that it represents. That is,
4878 VarDecl *InstantiationPattern = Template->getTemplatedDecl();
4879 TemplateArgumentList TemplateArgList(TemplateArgumentList::OnStack,
4880 CanonicalConverted);
4881 TemplateArgumentList *InstantiationArgs = &TemplateArgList;
4882 bool AmbiguousPartialSpec = false;
4883 typedef PartialSpecMatchResult MatchResult;
4884 SmallVector<MatchResult, 4> Matched;
4885 SourceLocation PointOfInstantiation = TemplateNameLoc;
4886 TemplateSpecCandidateSet FailedCandidates(PointOfInstantiation,
4887 /*ForTakingAddress=*/false);
4888
4889 // 1. Attempt to find the closest partial specialization that this
4890 // specializes, if any.
4891 // TODO: Unify with InstantiateClassTemplateSpecialization()?
4892 // Perhaps better after unification of DeduceTemplateArguments() and
4893 // getMoreSpecializedPartialSpecialization().
4894 SmallVector<VarTemplatePartialSpecializationDecl *, 4> PartialSpecs;
4895 Template->getPartialSpecializations(PartialSpecs);
4896
4897 for (unsigned I = 0, N = PartialSpecs.size(); I != N; ++I) {
4898 VarTemplatePartialSpecializationDecl *Partial = PartialSpecs[I];
4899 TemplateDeductionInfo Info(FailedCandidates.getLocation());
4900
4901 if (TemplateDeductionResult Result =
4902 DeduceTemplateArguments(Partial, TemplateArgList, Info)) {
4903 // Store the failed-deduction information for use in diagnostics, later.
4904 // TODO: Actually use the failed-deduction info?
4905 FailedCandidates.addCandidate().set(
4906 DeclAccessPair::make(Template, AS_public), Partial,
4907 MakeDeductionFailureInfo(Context, Result, Info));
4908 (void)Result;
4909 } else {
4910 Matched.push_back(PartialSpecMatchResult());
4911 Matched.back().Partial = Partial;
4912 Matched.back().Args = Info.takeCanonical();
4913 }
4914 }
4915
4916 if (Matched.size() >= 1) {
4917 SmallVector<MatchResult, 4>::iterator Best = Matched.begin();
4918 if (Matched.size() == 1) {
4919 // -- If exactly one matching specialization is found, the
4920 // instantiation is generated from that specialization.
4921 // We don't need to do anything for this.
4922 } else {
4923 // -- If more than one matching specialization is found, the
4924 // partial order rules (14.5.4.2) are used to determine
4925 // whether one of the specializations is more specialized
4926 // than the others. If none of the specializations is more
4927 // specialized than all of the other matching
4928 // specializations, then the use of the variable template is
4929 // ambiguous and the program is ill-formed.
4930 for (SmallVector<MatchResult, 4>::iterator P = Best + 1,
4931 PEnd = Matched.end();
4932 P != PEnd; ++P) {
4933 if (getMoreSpecializedPartialSpecialization(P->Partial, Best->Partial,
4934 PointOfInstantiation) ==
4935 P->Partial)
4936 Best = P;
4937 }
4938
4939 // Determine if the best partial specialization is more specialized than
4940 // the others.
4941 for (SmallVector<MatchResult, 4>::iterator P = Matched.begin(),
4942 PEnd = Matched.end();
4943 P != PEnd; ++P) {
4944 if (P != Best && getMoreSpecializedPartialSpecialization(
4945 P->Partial, Best->Partial,
4946 PointOfInstantiation) != Best->Partial) {
4947 AmbiguousPartialSpec = true;
4948 break;
4949 }
4950 }
4951 }
4952
4953 // Instantiate using the best variable template partial specialization.
4954 InstantiationPattern = Best->Partial;
4955 InstantiationArgs = Best->Args;
4956 } else {
4957 // -- If no match is found, the instantiation is generated
4958 // from the primary template.
4959 // InstantiationPattern = Template->getTemplatedDecl();
4960 }
4961
4962 // 2. Create the canonical declaration.
4963 // Note that we do not instantiate a definition until we see an odr-use
4964 // in DoMarkVarDeclReferenced().
4965 // FIXME: LateAttrs et al.?
4966 VarTemplateSpecializationDecl *Decl = BuildVarTemplateInstantiation(
4967 Template, InstantiationPattern, *InstantiationArgs, TemplateArgs,
4968 CanonicalConverted, TemplateNameLoc /*, LateAttrs, StartingScope*/);
4969 if (!Decl)
4970 return true;
4971
4972 if (AmbiguousPartialSpec) {
4973 // Partial ordering did not produce a clear winner. Complain.
4974 Decl->setInvalidDecl();
4975 Diag(PointOfInstantiation, diag::err_partial_spec_ordering_ambiguous)
4976 << Decl;
4977
4978 // Print the matching partial specializations.
4979 for (MatchResult P : Matched)
4980 Diag(P.Partial->getLocation(), diag::note_partial_spec_match)
4981 << getTemplateArgumentBindingsText(P.Partial->getTemplateParameters(),
4982 *P.Args);
4983 return true;
4984 }
4985
4986 if (VarTemplatePartialSpecializationDecl *D =
4987 dyn_cast<VarTemplatePartialSpecializationDecl>(InstantiationPattern))
4988 Decl->setInstantiationOf(D, InstantiationArgs);
4989
4990 checkSpecializationReachability(TemplateNameLoc, Decl);
4991
4992 assert(Decl && "No variable template specialization?");
4993 return Decl;
4994 }
4995
4996 ExprResult
CheckVarTemplateId(const CXXScopeSpec & SS,const DeclarationNameInfo & NameInfo,VarTemplateDecl * Template,SourceLocation TemplateLoc,const TemplateArgumentListInfo * TemplateArgs)4997 Sema::CheckVarTemplateId(const CXXScopeSpec &SS,
4998 const DeclarationNameInfo &NameInfo,
4999 VarTemplateDecl *Template, SourceLocation TemplateLoc,
5000 const TemplateArgumentListInfo *TemplateArgs) {
5001
5002 DeclResult Decl = CheckVarTemplateId(Template, TemplateLoc, NameInfo.getLoc(),
5003 *TemplateArgs);
5004 if (Decl.isInvalid())
5005 return ExprError();
5006
5007 if (!Decl.get())
5008 return ExprResult();
5009
5010 VarDecl *Var = cast<VarDecl>(Decl.get());
5011 if (!Var->getTemplateSpecializationKind())
5012 Var->setTemplateSpecializationKind(TSK_ImplicitInstantiation,
5013 NameInfo.getLoc());
5014
5015 // Build an ordinary singleton decl ref.
5016 return BuildDeclarationNameExpr(SS, NameInfo, Var,
5017 /*FoundD=*/nullptr, TemplateArgs);
5018 }
5019
diagnoseMissingTemplateArguments(TemplateName Name,SourceLocation Loc)5020 void Sema::diagnoseMissingTemplateArguments(TemplateName Name,
5021 SourceLocation Loc) {
5022 Diag(Loc, diag::err_template_missing_args)
5023 << (int)getTemplateNameKindForDiagnostics(Name) << Name;
5024 if (TemplateDecl *TD = Name.getAsTemplateDecl()) {
5025 NoteTemplateLocation(*TD, TD->getTemplateParameters()->getSourceRange());
5026 }
5027 }
5028
5029 ExprResult
CheckConceptTemplateId(const CXXScopeSpec & SS,SourceLocation TemplateKWLoc,const DeclarationNameInfo & ConceptNameInfo,NamedDecl * FoundDecl,ConceptDecl * NamedConcept,const TemplateArgumentListInfo * TemplateArgs)5030 Sema::CheckConceptTemplateId(const CXXScopeSpec &SS,
5031 SourceLocation TemplateKWLoc,
5032 const DeclarationNameInfo &ConceptNameInfo,
5033 NamedDecl *FoundDecl,
5034 ConceptDecl *NamedConcept,
5035 const TemplateArgumentListInfo *TemplateArgs) {
5036 assert(NamedConcept && "A concept template id without a template?");
5037
5038 llvm::SmallVector<TemplateArgument, 4> SugaredConverted, CanonicalConverted;
5039 if (CheckTemplateArgumentList(
5040 NamedConcept, ConceptNameInfo.getLoc(),
5041 const_cast<TemplateArgumentListInfo &>(*TemplateArgs),
5042 /*PartialTemplateArgs=*/false, SugaredConverted, CanonicalConverted,
5043 /*UpdateArgsWithConversions=*/false))
5044 return ExprError();
5045
5046 auto *CSD = ImplicitConceptSpecializationDecl::Create(
5047 Context, NamedConcept->getDeclContext(), NamedConcept->getLocation(),
5048 CanonicalConverted);
5049 ConstraintSatisfaction Satisfaction;
5050 bool AreArgsDependent =
5051 TemplateSpecializationType::anyDependentTemplateArguments(
5052 *TemplateArgs, CanonicalConverted);
5053 MultiLevelTemplateArgumentList MLTAL(NamedConcept, CanonicalConverted,
5054 /*Final=*/false);
5055 LocalInstantiationScope Scope(*this);
5056
5057 EnterExpressionEvaluationContext EECtx{
5058 *this, ExpressionEvaluationContext::ConstantEvaluated, CSD};
5059
5060 if (!AreArgsDependent &&
5061 CheckConstraintSatisfaction(
5062 NamedConcept, {NamedConcept->getConstraintExpr()}, MLTAL,
5063 SourceRange(SS.isSet() ? SS.getBeginLoc() : ConceptNameInfo.getLoc(),
5064 TemplateArgs->getRAngleLoc()),
5065 Satisfaction))
5066 return ExprError();
5067 auto *CL = ConceptReference::Create(
5068 Context,
5069 SS.isSet() ? SS.getWithLocInContext(Context) : NestedNameSpecifierLoc{},
5070 TemplateKWLoc, ConceptNameInfo, FoundDecl, NamedConcept,
5071 ASTTemplateArgumentListInfo::Create(Context, *TemplateArgs));
5072 return ConceptSpecializationExpr::Create(
5073 Context, CL, CSD, AreArgsDependent ? nullptr : &Satisfaction);
5074 }
5075
BuildTemplateIdExpr(const CXXScopeSpec & SS,SourceLocation TemplateKWLoc,LookupResult & R,bool RequiresADL,const TemplateArgumentListInfo * TemplateArgs)5076 ExprResult Sema::BuildTemplateIdExpr(const CXXScopeSpec &SS,
5077 SourceLocation TemplateKWLoc,
5078 LookupResult &R,
5079 bool RequiresADL,
5080 const TemplateArgumentListInfo *TemplateArgs) {
5081 // FIXME: Can we do any checking at this point? I guess we could check the
5082 // template arguments that we have against the template name, if the template
5083 // name refers to a single template. That's not a terribly common case,
5084 // though.
5085 // foo<int> could identify a single function unambiguously
5086 // This approach does NOT work, since f<int>(1);
5087 // gets resolved prior to resorting to overload resolution
5088 // i.e., template<class T> void f(double);
5089 // vs template<class T, class U> void f(U);
5090
5091 // These should be filtered out by our callers.
5092 assert(!R.isAmbiguous() && "ambiguous lookup when building templateid");
5093
5094 // Non-function templates require a template argument list.
5095 if (auto *TD = R.getAsSingle<TemplateDecl>()) {
5096 if (!TemplateArgs && !isa<FunctionTemplateDecl>(TD)) {
5097 diagnoseMissingTemplateArguments(TemplateName(TD), R.getNameLoc());
5098 return ExprError();
5099 }
5100 }
5101 bool KnownDependent = false;
5102 // In C++1y, check variable template ids.
5103 if (R.getAsSingle<VarTemplateDecl>()) {
5104 ExprResult Res = CheckVarTemplateId(SS, R.getLookupNameInfo(),
5105 R.getAsSingle<VarTemplateDecl>(),
5106 TemplateKWLoc, TemplateArgs);
5107 if (Res.isInvalid() || Res.isUsable())
5108 return Res;
5109 // Result is dependent. Carry on to build an UnresolvedLookupEpxr.
5110 KnownDependent = true;
5111 }
5112
5113 if (R.getAsSingle<ConceptDecl>()) {
5114 return CheckConceptTemplateId(SS, TemplateKWLoc, R.getLookupNameInfo(),
5115 R.getFoundDecl(),
5116 R.getAsSingle<ConceptDecl>(), TemplateArgs);
5117 }
5118
5119 // We don't want lookup warnings at this point.
5120 R.suppressDiagnostics();
5121
5122 UnresolvedLookupExpr *ULE = UnresolvedLookupExpr::Create(
5123 Context, R.getNamingClass(), SS.getWithLocInContext(Context),
5124 TemplateKWLoc, R.getLookupNameInfo(), RequiresADL, TemplateArgs,
5125 R.begin(), R.end(), KnownDependent);
5126
5127 return ULE;
5128 }
5129
5130 // We actually only call this from template instantiation.
5131 ExprResult
BuildQualifiedTemplateIdExpr(CXXScopeSpec & SS,SourceLocation TemplateKWLoc,const DeclarationNameInfo & NameInfo,const TemplateArgumentListInfo * TemplateArgs)5132 Sema::BuildQualifiedTemplateIdExpr(CXXScopeSpec &SS,
5133 SourceLocation TemplateKWLoc,
5134 const DeclarationNameInfo &NameInfo,
5135 const TemplateArgumentListInfo *TemplateArgs) {
5136
5137 assert(TemplateArgs || TemplateKWLoc.isValid());
5138 DeclContext *DC;
5139 if (!(DC = computeDeclContext(SS, false)) ||
5140 DC->isDependentContext() ||
5141 RequireCompleteDeclContext(SS, DC))
5142 return BuildDependentDeclRefExpr(SS, TemplateKWLoc, NameInfo, TemplateArgs);
5143
5144 bool MemberOfUnknownSpecialization;
5145 LookupResult R(*this, NameInfo, LookupOrdinaryName);
5146 if (LookupTemplateName(R, (Scope *)nullptr, SS, QualType(),
5147 /*Entering*/false, MemberOfUnknownSpecialization,
5148 TemplateKWLoc))
5149 return ExprError();
5150
5151 if (R.isAmbiguous())
5152 return ExprError();
5153
5154 if (R.empty()) {
5155 Diag(NameInfo.getLoc(), diag::err_no_member)
5156 << NameInfo.getName() << DC << SS.getRange();
5157 return ExprError();
5158 }
5159
5160 auto DiagnoseTypeTemplateDecl = [&](TemplateDecl *Temp,
5161 bool isTypeAliasTemplateDecl) {
5162 Diag(NameInfo.getLoc(), diag::err_template_kw_refers_to_type_template)
5163 << SS.getScopeRep() << NameInfo.getName().getAsString() << SS.getRange()
5164 << isTypeAliasTemplateDecl;
5165 Diag(Temp->getLocation(), diag::note_referenced_type_template) << 0;
5166 return ExprError();
5167 };
5168
5169 if (ClassTemplateDecl *Temp = R.getAsSingle<ClassTemplateDecl>())
5170 return DiagnoseTypeTemplateDecl(Temp, false);
5171
5172 if (TypeAliasTemplateDecl *Temp = R.getAsSingle<TypeAliasTemplateDecl>())
5173 return DiagnoseTypeTemplateDecl(Temp, true);
5174
5175 return BuildTemplateIdExpr(SS, TemplateKWLoc, R, /*ADL*/ false, TemplateArgs);
5176 }
5177
5178 /// Form a template name from a name that is syntactically required to name a
5179 /// template, either due to use of the 'template' keyword or because a name in
5180 /// this syntactic context is assumed to name a template (C++ [temp.names]p2-4).
5181 ///
5182 /// This action forms a template name given the name of the template and its
5183 /// optional scope specifier. This is used when the 'template' keyword is used
5184 /// or when the parsing context unambiguously treats a following '<' as
5185 /// introducing a template argument list. Note that this may produce a
5186 /// non-dependent template name if we can perform the lookup now and identify
5187 /// the named template.
5188 ///
5189 /// For example, given "x.MetaFun::template apply", the scope specifier
5190 /// \p SS will be "MetaFun::", \p TemplateKWLoc contains the location
5191 /// of the "template" keyword, and "apply" is the \p Name.
ActOnTemplateName(Scope * S,CXXScopeSpec & SS,SourceLocation TemplateKWLoc,const UnqualifiedId & Name,ParsedType ObjectType,bool EnteringContext,TemplateTy & Result,bool AllowInjectedClassName)5192 TemplateNameKind Sema::ActOnTemplateName(Scope *S,
5193 CXXScopeSpec &SS,
5194 SourceLocation TemplateKWLoc,
5195 const UnqualifiedId &Name,
5196 ParsedType ObjectType,
5197 bool EnteringContext,
5198 TemplateTy &Result,
5199 bool AllowInjectedClassName) {
5200 if (TemplateKWLoc.isValid() && S && !S->getTemplateParamParent())
5201 Diag(TemplateKWLoc,
5202 getLangOpts().CPlusPlus11 ?
5203 diag::warn_cxx98_compat_template_outside_of_template :
5204 diag::ext_template_outside_of_template)
5205 << FixItHint::CreateRemoval(TemplateKWLoc);
5206
5207 if (SS.isInvalid())
5208 return TNK_Non_template;
5209
5210 // Figure out where isTemplateName is going to look.
5211 DeclContext *LookupCtx = nullptr;
5212 if (SS.isNotEmpty())
5213 LookupCtx = computeDeclContext(SS, EnteringContext);
5214 else if (ObjectType)
5215 LookupCtx = computeDeclContext(GetTypeFromParser(ObjectType));
5216
5217 // C++0x [temp.names]p5:
5218 // If a name prefixed by the keyword template is not the name of
5219 // a template, the program is ill-formed. [Note: the keyword
5220 // template may not be applied to non-template members of class
5221 // templates. -end note ] [ Note: as is the case with the
5222 // typename prefix, the template prefix is allowed in cases
5223 // where it is not strictly necessary; i.e., when the
5224 // nested-name-specifier or the expression on the left of the ->
5225 // or . is not dependent on a template-parameter, or the use
5226 // does not appear in the scope of a template. -end note]
5227 //
5228 // Note: C++03 was more strict here, because it banned the use of
5229 // the "template" keyword prior to a template-name that was not a
5230 // dependent name. C++ DR468 relaxed this requirement (the
5231 // "template" keyword is now permitted). We follow the C++0x
5232 // rules, even in C++03 mode with a warning, retroactively applying the DR.
5233 bool MemberOfUnknownSpecialization;
5234 TemplateNameKind TNK = isTemplateName(S, SS, TemplateKWLoc.isValid(), Name,
5235 ObjectType, EnteringContext, Result,
5236 MemberOfUnknownSpecialization);
5237 if (TNK != TNK_Non_template) {
5238 // We resolved this to a (non-dependent) template name. Return it.
5239 auto *LookupRD = dyn_cast_or_null<CXXRecordDecl>(LookupCtx);
5240 if (!AllowInjectedClassName && SS.isNotEmpty() && LookupRD &&
5241 Name.getKind() == UnqualifiedIdKind::IK_Identifier &&
5242 Name.Identifier && LookupRD->getIdentifier() == Name.Identifier) {
5243 // C++14 [class.qual]p2:
5244 // In a lookup in which function names are not ignored and the
5245 // nested-name-specifier nominates a class C, if the name specified
5246 // [...] is the injected-class-name of C, [...] the name is instead
5247 // considered to name the constructor
5248 //
5249 // We don't get here if naming the constructor would be valid, so we
5250 // just reject immediately and recover by treating the
5251 // injected-class-name as naming the template.
5252 Diag(Name.getBeginLoc(),
5253 diag::ext_out_of_line_qualified_id_type_names_constructor)
5254 << Name.Identifier
5255 << 0 /*injected-class-name used as template name*/
5256 << TemplateKWLoc.isValid();
5257 }
5258 return TNK;
5259 }
5260
5261 if (!MemberOfUnknownSpecialization) {
5262 // Didn't find a template name, and the lookup wasn't dependent.
5263 // Do the lookup again to determine if this is a "nothing found" case or
5264 // a "not a template" case. FIXME: Refactor isTemplateName so we don't
5265 // need to do this.
5266 DeclarationNameInfo DNI = GetNameFromUnqualifiedId(Name);
5267 LookupResult R(*this, DNI.getName(), Name.getBeginLoc(),
5268 LookupOrdinaryName);
5269 bool MOUS;
5270 // Tell LookupTemplateName that we require a template so that it diagnoses
5271 // cases where it finds a non-template.
5272 RequiredTemplateKind RTK = TemplateKWLoc.isValid()
5273 ? RequiredTemplateKind(TemplateKWLoc)
5274 : TemplateNameIsRequired;
5275 if (!LookupTemplateName(R, S, SS, ObjectType.get(), EnteringContext, MOUS,
5276 RTK, nullptr, /*AllowTypoCorrection=*/false) &&
5277 !R.isAmbiguous()) {
5278 if (LookupCtx)
5279 Diag(Name.getBeginLoc(), diag::err_no_member)
5280 << DNI.getName() << LookupCtx << SS.getRange();
5281 else
5282 Diag(Name.getBeginLoc(), diag::err_undeclared_use)
5283 << DNI.getName() << SS.getRange();
5284 }
5285 return TNK_Non_template;
5286 }
5287
5288 NestedNameSpecifier *Qualifier = SS.getScopeRep();
5289
5290 switch (Name.getKind()) {
5291 case UnqualifiedIdKind::IK_Identifier:
5292 Result = TemplateTy::make(
5293 Context.getDependentTemplateName(Qualifier, Name.Identifier));
5294 return TNK_Dependent_template_name;
5295
5296 case UnqualifiedIdKind::IK_OperatorFunctionId:
5297 Result = TemplateTy::make(Context.getDependentTemplateName(
5298 Qualifier, Name.OperatorFunctionId.Operator));
5299 return TNK_Function_template;
5300
5301 case UnqualifiedIdKind::IK_LiteralOperatorId:
5302 // This is a kind of template name, but can never occur in a dependent
5303 // scope (literal operators can only be declared at namespace scope).
5304 break;
5305
5306 default:
5307 break;
5308 }
5309
5310 // This name cannot possibly name a dependent template. Diagnose this now
5311 // rather than building a dependent template name that can never be valid.
5312 Diag(Name.getBeginLoc(),
5313 diag::err_template_kw_refers_to_dependent_non_template)
5314 << GetNameFromUnqualifiedId(Name).getName() << Name.getSourceRange()
5315 << TemplateKWLoc.isValid() << TemplateKWLoc;
5316 return TNK_Non_template;
5317 }
5318
CheckTemplateTypeArgument(TemplateTypeParmDecl * Param,TemplateArgumentLoc & AL,SmallVectorImpl<TemplateArgument> & SugaredConverted,SmallVectorImpl<TemplateArgument> & CanonicalConverted)5319 bool Sema::CheckTemplateTypeArgument(
5320 TemplateTypeParmDecl *Param, TemplateArgumentLoc &AL,
5321 SmallVectorImpl<TemplateArgument> &SugaredConverted,
5322 SmallVectorImpl<TemplateArgument> &CanonicalConverted) {
5323 const TemplateArgument &Arg = AL.getArgument();
5324 QualType ArgType;
5325 TypeSourceInfo *TSI = nullptr;
5326
5327 // Check template type parameter.
5328 switch(Arg.getKind()) {
5329 case TemplateArgument::Type:
5330 // C++ [temp.arg.type]p1:
5331 // A template-argument for a template-parameter which is a
5332 // type shall be a type-id.
5333 ArgType = Arg.getAsType();
5334 TSI = AL.getTypeSourceInfo();
5335 break;
5336 case TemplateArgument::Template:
5337 case TemplateArgument::TemplateExpansion: {
5338 // We have a template type parameter but the template argument
5339 // is a template without any arguments.
5340 SourceRange SR = AL.getSourceRange();
5341 TemplateName Name = Arg.getAsTemplateOrTemplatePattern();
5342 diagnoseMissingTemplateArguments(Name, SR.getEnd());
5343 return true;
5344 }
5345 case TemplateArgument::Expression: {
5346 // We have a template type parameter but the template argument is an
5347 // expression; see if maybe it is missing the "typename" keyword.
5348 CXXScopeSpec SS;
5349 DeclarationNameInfo NameInfo;
5350
5351 if (DependentScopeDeclRefExpr *ArgExpr =
5352 dyn_cast<DependentScopeDeclRefExpr>(Arg.getAsExpr())) {
5353 SS.Adopt(ArgExpr->getQualifierLoc());
5354 NameInfo = ArgExpr->getNameInfo();
5355 } else if (CXXDependentScopeMemberExpr *ArgExpr =
5356 dyn_cast<CXXDependentScopeMemberExpr>(Arg.getAsExpr())) {
5357 if (ArgExpr->isImplicitAccess()) {
5358 SS.Adopt(ArgExpr->getQualifierLoc());
5359 NameInfo = ArgExpr->getMemberNameInfo();
5360 }
5361 }
5362
5363 if (auto *II = NameInfo.getName().getAsIdentifierInfo()) {
5364 LookupResult Result(*this, NameInfo, LookupOrdinaryName);
5365 LookupParsedName(Result, CurScope, &SS);
5366
5367 if (Result.getAsSingle<TypeDecl>() ||
5368 Result.getResultKind() ==
5369 LookupResult::NotFoundInCurrentInstantiation) {
5370 assert(SS.getScopeRep() && "dependent scope expr must has a scope!");
5371 // Suggest that the user add 'typename' before the NNS.
5372 SourceLocation Loc = AL.getSourceRange().getBegin();
5373 Diag(Loc, getLangOpts().MSVCCompat
5374 ? diag::ext_ms_template_type_arg_missing_typename
5375 : diag::err_template_arg_must_be_type_suggest)
5376 << FixItHint::CreateInsertion(Loc, "typename ");
5377 NoteTemplateParameterLocation(*Param);
5378
5379 // Recover by synthesizing a type using the location information that we
5380 // already have.
5381 ArgType = Context.getDependentNameType(ElaboratedTypeKeyword::Typename,
5382 SS.getScopeRep(), II);
5383 TypeLocBuilder TLB;
5384 DependentNameTypeLoc TL = TLB.push<DependentNameTypeLoc>(ArgType);
5385 TL.setElaboratedKeywordLoc(SourceLocation(/*synthesized*/));
5386 TL.setQualifierLoc(SS.getWithLocInContext(Context));
5387 TL.setNameLoc(NameInfo.getLoc());
5388 TSI = TLB.getTypeSourceInfo(Context, ArgType);
5389
5390 // Overwrite our input TemplateArgumentLoc so that we can recover
5391 // properly.
5392 AL = TemplateArgumentLoc(TemplateArgument(ArgType),
5393 TemplateArgumentLocInfo(TSI));
5394
5395 break;
5396 }
5397 }
5398 // fallthrough
5399 [[fallthrough]];
5400 }
5401 default: {
5402 // We have a template type parameter but the template argument
5403 // is not a type.
5404 SourceRange SR = AL.getSourceRange();
5405 Diag(SR.getBegin(), diag::err_template_arg_must_be_type) << SR;
5406 NoteTemplateParameterLocation(*Param);
5407
5408 return true;
5409 }
5410 }
5411
5412 if (CheckTemplateArgument(TSI))
5413 return true;
5414
5415 // Objective-C ARC:
5416 // If an explicitly-specified template argument type is a lifetime type
5417 // with no lifetime qualifier, the __strong lifetime qualifier is inferred.
5418 if (getLangOpts().ObjCAutoRefCount &&
5419 ArgType->isObjCLifetimeType() &&
5420 !ArgType.getObjCLifetime()) {
5421 Qualifiers Qs;
5422 Qs.setObjCLifetime(Qualifiers::OCL_Strong);
5423 ArgType = Context.getQualifiedType(ArgType, Qs);
5424 }
5425
5426 SugaredConverted.push_back(TemplateArgument(ArgType));
5427 CanonicalConverted.push_back(
5428 TemplateArgument(Context.getCanonicalType(ArgType)));
5429 return false;
5430 }
5431
5432 /// Substitute template arguments into the default template argument for
5433 /// the given template type parameter.
5434 ///
5435 /// \param SemaRef the semantic analysis object for which we are performing
5436 /// the substitution.
5437 ///
5438 /// \param Template the template that we are synthesizing template arguments
5439 /// for.
5440 ///
5441 /// \param TemplateLoc the location of the template name that started the
5442 /// template-id we are checking.
5443 ///
5444 /// \param RAngleLoc the location of the right angle bracket ('>') that
5445 /// terminates the template-id.
5446 ///
5447 /// \param Param the template template parameter whose default we are
5448 /// substituting into.
5449 ///
5450 /// \param Converted the list of template arguments provided for template
5451 /// parameters that precede \p Param in the template parameter list.
5452 /// \returns the substituted template argument, or NULL if an error occurred.
SubstDefaultTemplateArgument(Sema & SemaRef,TemplateDecl * Template,SourceLocation TemplateLoc,SourceLocation RAngleLoc,TemplateTypeParmDecl * Param,ArrayRef<TemplateArgument> SugaredConverted,ArrayRef<TemplateArgument> CanonicalConverted)5453 static TypeSourceInfo *SubstDefaultTemplateArgument(
5454 Sema &SemaRef, TemplateDecl *Template, SourceLocation TemplateLoc,
5455 SourceLocation RAngleLoc, TemplateTypeParmDecl *Param,
5456 ArrayRef<TemplateArgument> SugaredConverted,
5457 ArrayRef<TemplateArgument> CanonicalConverted) {
5458 TypeSourceInfo *ArgType = Param->getDefaultArgumentInfo();
5459
5460 // If the argument type is dependent, instantiate it now based
5461 // on the previously-computed template arguments.
5462 if (ArgType->getType()->isInstantiationDependentType()) {
5463 Sema::InstantiatingTemplate Inst(SemaRef, TemplateLoc, Param, Template,
5464 SugaredConverted,
5465 SourceRange(TemplateLoc, RAngleLoc));
5466 if (Inst.isInvalid())
5467 return nullptr;
5468
5469 // Only substitute for the innermost template argument list.
5470 MultiLevelTemplateArgumentList TemplateArgLists(Template, SugaredConverted,
5471 /*Final=*/true);
5472 for (unsigned i = 0, e = Param->getDepth(); i != e; ++i)
5473 TemplateArgLists.addOuterTemplateArguments(std::nullopt);
5474
5475 bool ForLambdaCallOperator = false;
5476 if (const auto *Rec = dyn_cast<CXXRecordDecl>(Template->getDeclContext()))
5477 ForLambdaCallOperator = Rec->isLambda();
5478 Sema::ContextRAII SavedContext(SemaRef, Template->getDeclContext(),
5479 !ForLambdaCallOperator);
5480 ArgType =
5481 SemaRef.SubstType(ArgType, TemplateArgLists,
5482 Param->getDefaultArgumentLoc(), Param->getDeclName());
5483 }
5484
5485 return ArgType;
5486 }
5487
5488 /// Substitute template arguments into the default template argument for
5489 /// the given non-type template parameter.
5490 ///
5491 /// \param SemaRef the semantic analysis object for which we are performing
5492 /// the substitution.
5493 ///
5494 /// \param Template the template that we are synthesizing template arguments
5495 /// for.
5496 ///
5497 /// \param TemplateLoc the location of the template name that started the
5498 /// template-id we are checking.
5499 ///
5500 /// \param RAngleLoc the location of the right angle bracket ('>') that
5501 /// terminates the template-id.
5502 ///
5503 /// \param Param the non-type template parameter whose default we are
5504 /// substituting into.
5505 ///
5506 /// \param Converted the list of template arguments provided for template
5507 /// parameters that precede \p Param in the template parameter list.
5508 ///
5509 /// \returns the substituted template argument, or NULL if an error occurred.
SubstDefaultTemplateArgument(Sema & SemaRef,TemplateDecl * Template,SourceLocation TemplateLoc,SourceLocation RAngleLoc,NonTypeTemplateParmDecl * Param,ArrayRef<TemplateArgument> SugaredConverted,ArrayRef<TemplateArgument> CanonicalConverted)5510 static ExprResult SubstDefaultTemplateArgument(
5511 Sema &SemaRef, TemplateDecl *Template, SourceLocation TemplateLoc,
5512 SourceLocation RAngleLoc, NonTypeTemplateParmDecl *Param,
5513 ArrayRef<TemplateArgument> SugaredConverted,
5514 ArrayRef<TemplateArgument> CanonicalConverted) {
5515 Sema::InstantiatingTemplate Inst(SemaRef, TemplateLoc, Param, Template,
5516 SugaredConverted,
5517 SourceRange(TemplateLoc, RAngleLoc));
5518 if (Inst.isInvalid())
5519 return ExprError();
5520
5521 // Only substitute for the innermost template argument list.
5522 MultiLevelTemplateArgumentList TemplateArgLists(Template, SugaredConverted,
5523 /*Final=*/true);
5524 for (unsigned i = 0, e = Param->getDepth(); i != e; ++i)
5525 TemplateArgLists.addOuterTemplateArguments(std::nullopt);
5526
5527 Sema::ContextRAII SavedContext(SemaRef, Template->getDeclContext());
5528 EnterExpressionEvaluationContext ConstantEvaluated(
5529 SemaRef, Sema::ExpressionEvaluationContext::ConstantEvaluated);
5530 return SemaRef.SubstExpr(Param->getDefaultArgument(), TemplateArgLists);
5531 }
5532
5533 /// Substitute template arguments into the default template argument for
5534 /// the given template template parameter.
5535 ///
5536 /// \param SemaRef the semantic analysis object for which we are performing
5537 /// the substitution.
5538 ///
5539 /// \param Template the template that we are synthesizing template arguments
5540 /// for.
5541 ///
5542 /// \param TemplateLoc the location of the template name that started the
5543 /// template-id we are checking.
5544 ///
5545 /// \param RAngleLoc the location of the right angle bracket ('>') that
5546 /// terminates the template-id.
5547 ///
5548 /// \param Param the template template parameter whose default we are
5549 /// substituting into.
5550 ///
5551 /// \param Converted the list of template arguments provided for template
5552 /// parameters that precede \p Param in the template parameter list.
5553 ///
5554 /// \param QualifierLoc Will be set to the nested-name-specifier (with
5555 /// source-location information) that precedes the template name.
5556 ///
5557 /// \returns the substituted template argument, or NULL if an error occurred.
SubstDefaultTemplateArgument(Sema & SemaRef,TemplateDecl * Template,SourceLocation TemplateLoc,SourceLocation RAngleLoc,TemplateTemplateParmDecl * Param,ArrayRef<TemplateArgument> SugaredConverted,ArrayRef<TemplateArgument> CanonicalConverted,NestedNameSpecifierLoc & QualifierLoc)5558 static TemplateName SubstDefaultTemplateArgument(
5559 Sema &SemaRef, TemplateDecl *Template, SourceLocation TemplateLoc,
5560 SourceLocation RAngleLoc, TemplateTemplateParmDecl *Param,
5561 ArrayRef<TemplateArgument> SugaredConverted,
5562 ArrayRef<TemplateArgument> CanonicalConverted,
5563 NestedNameSpecifierLoc &QualifierLoc) {
5564 Sema::InstantiatingTemplate Inst(
5565 SemaRef, TemplateLoc, TemplateParameter(Param), Template,
5566 SugaredConverted, SourceRange(TemplateLoc, RAngleLoc));
5567 if (Inst.isInvalid())
5568 return TemplateName();
5569
5570 // Only substitute for the innermost template argument list.
5571 MultiLevelTemplateArgumentList TemplateArgLists(Template, SugaredConverted,
5572 /*Final=*/true);
5573 for (unsigned i = 0, e = Param->getDepth(); i != e; ++i)
5574 TemplateArgLists.addOuterTemplateArguments(std::nullopt);
5575
5576 Sema::ContextRAII SavedContext(SemaRef, Template->getDeclContext());
5577 // Substitute into the nested-name-specifier first,
5578 QualifierLoc = Param->getDefaultArgument().getTemplateQualifierLoc();
5579 if (QualifierLoc) {
5580 QualifierLoc =
5581 SemaRef.SubstNestedNameSpecifierLoc(QualifierLoc, TemplateArgLists);
5582 if (!QualifierLoc)
5583 return TemplateName();
5584 }
5585
5586 return SemaRef.SubstTemplateName(
5587 QualifierLoc,
5588 Param->getDefaultArgument().getArgument().getAsTemplate(),
5589 Param->getDefaultArgument().getTemplateNameLoc(),
5590 TemplateArgLists);
5591 }
5592
5593 /// If the given template parameter has a default template
5594 /// argument, substitute into that default template argument and
5595 /// return the corresponding template argument.
SubstDefaultTemplateArgumentIfAvailable(TemplateDecl * Template,SourceLocation TemplateLoc,SourceLocation RAngleLoc,Decl * Param,ArrayRef<TemplateArgument> SugaredConverted,ArrayRef<TemplateArgument> CanonicalConverted,bool & HasDefaultArg)5596 TemplateArgumentLoc Sema::SubstDefaultTemplateArgumentIfAvailable(
5597 TemplateDecl *Template, SourceLocation TemplateLoc,
5598 SourceLocation RAngleLoc, Decl *Param,
5599 ArrayRef<TemplateArgument> SugaredConverted,
5600 ArrayRef<TemplateArgument> CanonicalConverted, bool &HasDefaultArg) {
5601 HasDefaultArg = false;
5602
5603 if (TemplateTypeParmDecl *TypeParm = dyn_cast<TemplateTypeParmDecl>(Param)) {
5604 if (!hasReachableDefaultArgument(TypeParm))
5605 return TemplateArgumentLoc();
5606
5607 HasDefaultArg = true;
5608 TypeSourceInfo *DI = SubstDefaultTemplateArgument(
5609 *this, Template, TemplateLoc, RAngleLoc, TypeParm, SugaredConverted,
5610 CanonicalConverted);
5611 if (DI)
5612 return TemplateArgumentLoc(TemplateArgument(DI->getType()), DI);
5613
5614 return TemplateArgumentLoc();
5615 }
5616
5617 if (NonTypeTemplateParmDecl *NonTypeParm
5618 = dyn_cast<NonTypeTemplateParmDecl>(Param)) {
5619 if (!hasReachableDefaultArgument(NonTypeParm))
5620 return TemplateArgumentLoc();
5621
5622 HasDefaultArg = true;
5623 ExprResult Arg = SubstDefaultTemplateArgument(
5624 *this, Template, TemplateLoc, RAngleLoc, NonTypeParm, SugaredConverted,
5625 CanonicalConverted);
5626 if (Arg.isInvalid())
5627 return TemplateArgumentLoc();
5628
5629 Expr *ArgE = Arg.getAs<Expr>();
5630 return TemplateArgumentLoc(TemplateArgument(ArgE), ArgE);
5631 }
5632
5633 TemplateTemplateParmDecl *TempTempParm
5634 = cast<TemplateTemplateParmDecl>(Param);
5635 if (!hasReachableDefaultArgument(TempTempParm))
5636 return TemplateArgumentLoc();
5637
5638 HasDefaultArg = true;
5639 NestedNameSpecifierLoc QualifierLoc;
5640 TemplateName TName = SubstDefaultTemplateArgument(
5641 *this, Template, TemplateLoc, RAngleLoc, TempTempParm, SugaredConverted,
5642 CanonicalConverted, QualifierLoc);
5643 if (TName.isNull())
5644 return TemplateArgumentLoc();
5645
5646 return TemplateArgumentLoc(
5647 Context, TemplateArgument(TName),
5648 TempTempParm->getDefaultArgument().getTemplateQualifierLoc(),
5649 TempTempParm->getDefaultArgument().getTemplateNameLoc());
5650 }
5651
5652 /// Convert a template-argument that we parsed as a type into a template, if
5653 /// possible. C++ permits injected-class-names to perform dual service as
5654 /// template template arguments and as template type arguments.
5655 static TemplateArgumentLoc
convertTypeTemplateArgumentToTemplate(ASTContext & Context,TypeLoc TLoc)5656 convertTypeTemplateArgumentToTemplate(ASTContext &Context, TypeLoc TLoc) {
5657 // Extract and step over any surrounding nested-name-specifier.
5658 NestedNameSpecifierLoc QualLoc;
5659 if (auto ETLoc = TLoc.getAs<ElaboratedTypeLoc>()) {
5660 if (ETLoc.getTypePtr()->getKeyword() != ElaboratedTypeKeyword::None)
5661 return TemplateArgumentLoc();
5662
5663 QualLoc = ETLoc.getQualifierLoc();
5664 TLoc = ETLoc.getNamedTypeLoc();
5665 }
5666 // If this type was written as an injected-class-name, it can be used as a
5667 // template template argument.
5668 if (auto InjLoc = TLoc.getAs<InjectedClassNameTypeLoc>())
5669 return TemplateArgumentLoc(Context, InjLoc.getTypePtr()->getTemplateName(),
5670 QualLoc, InjLoc.getNameLoc());
5671
5672 // If this type was written as an injected-class-name, it may have been
5673 // converted to a RecordType during instantiation. If the RecordType is
5674 // *not* wrapped in a TemplateSpecializationType and denotes a class
5675 // template specialization, it must have come from an injected-class-name.
5676 if (auto RecLoc = TLoc.getAs<RecordTypeLoc>())
5677 if (auto *CTSD =
5678 dyn_cast<ClassTemplateSpecializationDecl>(RecLoc.getDecl()))
5679 return TemplateArgumentLoc(Context,
5680 TemplateName(CTSD->getSpecializedTemplate()),
5681 QualLoc, RecLoc.getNameLoc());
5682
5683 return TemplateArgumentLoc();
5684 }
5685
5686 /// Check that the given template argument corresponds to the given
5687 /// template parameter.
5688 ///
5689 /// \param Param The template parameter against which the argument will be
5690 /// checked.
5691 ///
5692 /// \param Arg The template argument, which may be updated due to conversions.
5693 ///
5694 /// \param Template The template in which the template argument resides.
5695 ///
5696 /// \param TemplateLoc The location of the template name for the template
5697 /// whose argument list we're matching.
5698 ///
5699 /// \param RAngleLoc The location of the right angle bracket ('>') that closes
5700 /// the template argument list.
5701 ///
5702 /// \param ArgumentPackIndex The index into the argument pack where this
5703 /// argument will be placed. Only valid if the parameter is a parameter pack.
5704 ///
5705 /// \param Converted The checked, converted argument will be added to the
5706 /// end of this small vector.
5707 ///
5708 /// \param CTAK Describes how we arrived at this particular template argument:
5709 /// explicitly written, deduced, etc.
5710 ///
5711 /// \returns true on error, false otherwise.
CheckTemplateArgument(NamedDecl * Param,TemplateArgumentLoc & Arg,NamedDecl * Template,SourceLocation TemplateLoc,SourceLocation RAngleLoc,unsigned ArgumentPackIndex,SmallVectorImpl<TemplateArgument> & SugaredConverted,SmallVectorImpl<TemplateArgument> & CanonicalConverted,CheckTemplateArgumentKind CTAK)5712 bool Sema::CheckTemplateArgument(
5713 NamedDecl *Param, TemplateArgumentLoc &Arg, NamedDecl *Template,
5714 SourceLocation TemplateLoc, SourceLocation RAngleLoc,
5715 unsigned ArgumentPackIndex,
5716 SmallVectorImpl<TemplateArgument> &SugaredConverted,
5717 SmallVectorImpl<TemplateArgument> &CanonicalConverted,
5718 CheckTemplateArgumentKind CTAK) {
5719 // Check template type parameters.
5720 if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(Param))
5721 return CheckTemplateTypeArgument(TTP, Arg, SugaredConverted,
5722 CanonicalConverted);
5723
5724 // Check non-type template parameters.
5725 if (NonTypeTemplateParmDecl *NTTP =dyn_cast<NonTypeTemplateParmDecl>(Param)) {
5726 // Do substitution on the type of the non-type template parameter
5727 // with the template arguments we've seen thus far. But if the
5728 // template has a dependent context then we cannot substitute yet.
5729 QualType NTTPType = NTTP->getType();
5730 if (NTTP->isParameterPack() && NTTP->isExpandedParameterPack())
5731 NTTPType = NTTP->getExpansionType(ArgumentPackIndex);
5732
5733 if (NTTPType->isInstantiationDependentType() &&
5734 !isa<TemplateTemplateParmDecl>(Template) &&
5735 !Template->getDeclContext()->isDependentContext()) {
5736 // Do substitution on the type of the non-type template parameter.
5737 InstantiatingTemplate Inst(*this, TemplateLoc, Template, NTTP,
5738 SugaredConverted,
5739 SourceRange(TemplateLoc, RAngleLoc));
5740 if (Inst.isInvalid())
5741 return true;
5742
5743 MultiLevelTemplateArgumentList MLTAL(Template, SugaredConverted,
5744 /*Final=*/true);
5745 // If the parameter is a pack expansion, expand this slice of the pack.
5746 if (auto *PET = NTTPType->getAs<PackExpansionType>()) {
5747 Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(*this,
5748 ArgumentPackIndex);
5749 NTTPType = SubstType(PET->getPattern(), MLTAL, NTTP->getLocation(),
5750 NTTP->getDeclName());
5751 } else {
5752 NTTPType = SubstType(NTTPType, MLTAL, NTTP->getLocation(),
5753 NTTP->getDeclName());
5754 }
5755
5756 // If that worked, check the non-type template parameter type
5757 // for validity.
5758 if (!NTTPType.isNull())
5759 NTTPType = CheckNonTypeTemplateParameterType(NTTPType,
5760 NTTP->getLocation());
5761 if (NTTPType.isNull())
5762 return true;
5763 }
5764
5765 switch (Arg.getArgument().getKind()) {
5766 case TemplateArgument::Null:
5767 llvm_unreachable("Should never see a NULL template argument here");
5768
5769 case TemplateArgument::Expression: {
5770 Expr *E = Arg.getArgument().getAsExpr();
5771 TemplateArgument SugaredResult, CanonicalResult;
5772 unsigned CurSFINAEErrors = NumSFINAEErrors;
5773 ExprResult Res = CheckTemplateArgument(NTTP, NTTPType, E, SugaredResult,
5774 CanonicalResult, CTAK);
5775 if (Res.isInvalid())
5776 return true;
5777 // If the current template argument causes an error, give up now.
5778 if (CurSFINAEErrors < NumSFINAEErrors)
5779 return true;
5780
5781 // If the resulting expression is new, then use it in place of the
5782 // old expression in the template argument.
5783 if (Res.get() != E) {
5784 TemplateArgument TA(Res.get());
5785 Arg = TemplateArgumentLoc(TA, Res.get());
5786 }
5787
5788 SugaredConverted.push_back(SugaredResult);
5789 CanonicalConverted.push_back(CanonicalResult);
5790 break;
5791 }
5792
5793 case TemplateArgument::Declaration:
5794 case TemplateArgument::Integral:
5795 case TemplateArgument::StructuralValue:
5796 case TemplateArgument::NullPtr:
5797 // We've already checked this template argument, so just copy
5798 // it to the list of converted arguments.
5799 SugaredConverted.push_back(Arg.getArgument());
5800 CanonicalConverted.push_back(
5801 Context.getCanonicalTemplateArgument(Arg.getArgument()));
5802 break;
5803
5804 case TemplateArgument::Template:
5805 case TemplateArgument::TemplateExpansion:
5806 // We were given a template template argument. It may not be ill-formed;
5807 // see below.
5808 if (DependentTemplateName *DTN
5809 = Arg.getArgument().getAsTemplateOrTemplatePattern()
5810 .getAsDependentTemplateName()) {
5811 // We have a template argument such as \c T::template X, which we
5812 // parsed as a template template argument. However, since we now
5813 // know that we need a non-type template argument, convert this
5814 // template name into an expression.
5815
5816 DeclarationNameInfo NameInfo(DTN->getIdentifier(),
5817 Arg.getTemplateNameLoc());
5818
5819 CXXScopeSpec SS;
5820 SS.Adopt(Arg.getTemplateQualifierLoc());
5821 // FIXME: the template-template arg was a DependentTemplateName,
5822 // so it was provided with a template keyword. However, its source
5823 // location is not stored in the template argument structure.
5824 SourceLocation TemplateKWLoc;
5825 ExprResult E = DependentScopeDeclRefExpr::Create(
5826 Context, SS.getWithLocInContext(Context), TemplateKWLoc, NameInfo,
5827 nullptr);
5828
5829 // If we parsed the template argument as a pack expansion, create a
5830 // pack expansion expression.
5831 if (Arg.getArgument().getKind() == TemplateArgument::TemplateExpansion){
5832 E = ActOnPackExpansion(E.get(), Arg.getTemplateEllipsisLoc());
5833 if (E.isInvalid())
5834 return true;
5835 }
5836
5837 TemplateArgument SugaredResult, CanonicalResult;
5838 E = CheckTemplateArgument(NTTP, NTTPType, E.get(), SugaredResult,
5839 CanonicalResult, CTAK_Specified);
5840 if (E.isInvalid())
5841 return true;
5842
5843 SugaredConverted.push_back(SugaredResult);
5844 CanonicalConverted.push_back(CanonicalResult);
5845 break;
5846 }
5847
5848 // We have a template argument that actually does refer to a class
5849 // template, alias template, or template template parameter, and
5850 // therefore cannot be a non-type template argument.
5851 Diag(Arg.getLocation(), diag::err_template_arg_must_be_expr)
5852 << Arg.getSourceRange();
5853 NoteTemplateParameterLocation(*Param);
5854
5855 return true;
5856
5857 case TemplateArgument::Type: {
5858 // We have a non-type template parameter but the template
5859 // argument is a type.
5860
5861 // C++ [temp.arg]p2:
5862 // In a template-argument, an ambiguity between a type-id and
5863 // an expression is resolved to a type-id, regardless of the
5864 // form of the corresponding template-parameter.
5865 //
5866 // We warn specifically about this case, since it can be rather
5867 // confusing for users.
5868 QualType T = Arg.getArgument().getAsType();
5869 SourceRange SR = Arg.getSourceRange();
5870 if (T->isFunctionType())
5871 Diag(SR.getBegin(), diag::err_template_arg_nontype_ambig) << SR << T;
5872 else
5873 Diag(SR.getBegin(), diag::err_template_arg_must_be_expr) << SR;
5874 NoteTemplateParameterLocation(*Param);
5875 return true;
5876 }
5877
5878 case TemplateArgument::Pack:
5879 llvm_unreachable("Caller must expand template argument packs");
5880 }
5881
5882 return false;
5883 }
5884
5885
5886 // Check template template parameters.
5887 TemplateTemplateParmDecl *TempParm = cast<TemplateTemplateParmDecl>(Param);
5888
5889 TemplateParameterList *Params = TempParm->getTemplateParameters();
5890 if (TempParm->isExpandedParameterPack())
5891 Params = TempParm->getExpansionTemplateParameters(ArgumentPackIndex);
5892
5893 // Substitute into the template parameter list of the template
5894 // template parameter, since previously-supplied template arguments
5895 // may appear within the template template parameter.
5896 //
5897 // FIXME: Skip this if the parameters aren't instantiation-dependent.
5898 {
5899 // Set up a template instantiation context.
5900 LocalInstantiationScope Scope(*this);
5901 InstantiatingTemplate Inst(*this, TemplateLoc, Template, TempParm,
5902 SugaredConverted,
5903 SourceRange(TemplateLoc, RAngleLoc));
5904 if (Inst.isInvalid())
5905 return true;
5906
5907 Params =
5908 SubstTemplateParams(Params, CurContext,
5909 MultiLevelTemplateArgumentList(
5910 Template, SugaredConverted, /*Final=*/true),
5911 /*EvaluateConstraints=*/false);
5912 if (!Params)
5913 return true;
5914 }
5915
5916 // C++1z [temp.local]p1: (DR1004)
5917 // When [the injected-class-name] is used [...] as a template-argument for
5918 // a template template-parameter [...] it refers to the class template
5919 // itself.
5920 if (Arg.getArgument().getKind() == TemplateArgument::Type) {
5921 TemplateArgumentLoc ConvertedArg = convertTypeTemplateArgumentToTemplate(
5922 Context, Arg.getTypeSourceInfo()->getTypeLoc());
5923 if (!ConvertedArg.getArgument().isNull())
5924 Arg = ConvertedArg;
5925 }
5926
5927 switch (Arg.getArgument().getKind()) {
5928 case TemplateArgument::Null:
5929 llvm_unreachable("Should never see a NULL template argument here");
5930
5931 case TemplateArgument::Template:
5932 case TemplateArgument::TemplateExpansion:
5933 if (CheckTemplateTemplateArgument(TempParm, Params, Arg))
5934 return true;
5935
5936 SugaredConverted.push_back(Arg.getArgument());
5937 CanonicalConverted.push_back(
5938 Context.getCanonicalTemplateArgument(Arg.getArgument()));
5939 break;
5940
5941 case TemplateArgument::Expression:
5942 case TemplateArgument::Type:
5943 // We have a template template parameter but the template
5944 // argument does not refer to a template.
5945 Diag(Arg.getLocation(), diag::err_template_arg_must_be_template)
5946 << getLangOpts().CPlusPlus11;
5947 return true;
5948
5949 case TemplateArgument::Declaration:
5950 case TemplateArgument::Integral:
5951 case TemplateArgument::StructuralValue:
5952 case TemplateArgument::NullPtr:
5953 llvm_unreachable("non-type argument with template template parameter");
5954
5955 case TemplateArgument::Pack:
5956 llvm_unreachable("Caller must expand template argument packs");
5957 }
5958
5959 return false;
5960 }
5961
5962 /// Diagnose a missing template argument.
5963 template<typename TemplateParmDecl>
diagnoseMissingArgument(Sema & S,SourceLocation Loc,TemplateDecl * TD,const TemplateParmDecl * D,TemplateArgumentListInfo & Args)5964 static bool diagnoseMissingArgument(Sema &S, SourceLocation Loc,
5965 TemplateDecl *TD,
5966 const TemplateParmDecl *D,
5967 TemplateArgumentListInfo &Args) {
5968 // Dig out the most recent declaration of the template parameter; there may be
5969 // declarations of the template that are more recent than TD.
5970 D = cast<TemplateParmDecl>(cast<TemplateDecl>(TD->getMostRecentDecl())
5971 ->getTemplateParameters()
5972 ->getParam(D->getIndex()));
5973
5974 // If there's a default argument that's not reachable, diagnose that we're
5975 // missing a module import.
5976 llvm::SmallVector<Module*, 8> Modules;
5977 if (D->hasDefaultArgument() && !S.hasReachableDefaultArgument(D, &Modules)) {
5978 S.diagnoseMissingImport(Loc, cast<NamedDecl>(TD),
5979 D->getDefaultArgumentLoc(), Modules,
5980 Sema::MissingImportKind::DefaultArgument,
5981 /*Recover*/true);
5982 return true;
5983 }
5984
5985 // FIXME: If there's a more recent default argument that *is* visible,
5986 // diagnose that it was declared too late.
5987
5988 TemplateParameterList *Params = TD->getTemplateParameters();
5989
5990 S.Diag(Loc, diag::err_template_arg_list_different_arity)
5991 << /*not enough args*/0
5992 << (int)S.getTemplateNameKindForDiagnostics(TemplateName(TD))
5993 << TD;
5994 S.NoteTemplateLocation(*TD, Params->getSourceRange());
5995 return true;
5996 }
5997
5998 /// Check that the given template argument list is well-formed
5999 /// for specializing the given template.
CheckTemplateArgumentList(TemplateDecl * Template,SourceLocation TemplateLoc,TemplateArgumentListInfo & TemplateArgs,bool PartialTemplateArgs,SmallVectorImpl<TemplateArgument> & SugaredConverted,SmallVectorImpl<TemplateArgument> & CanonicalConverted,bool UpdateArgsWithConversions,bool * ConstraintsNotSatisfied)6000 bool Sema::CheckTemplateArgumentList(
6001 TemplateDecl *Template, SourceLocation TemplateLoc,
6002 TemplateArgumentListInfo &TemplateArgs, bool PartialTemplateArgs,
6003 SmallVectorImpl<TemplateArgument> &SugaredConverted,
6004 SmallVectorImpl<TemplateArgument> &CanonicalConverted,
6005 bool UpdateArgsWithConversions, bool *ConstraintsNotSatisfied) {
6006
6007 if (ConstraintsNotSatisfied)
6008 *ConstraintsNotSatisfied = false;
6009
6010 // Make a copy of the template arguments for processing. Only make the
6011 // changes at the end when successful in matching the arguments to the
6012 // template.
6013 TemplateArgumentListInfo NewArgs = TemplateArgs;
6014
6015 TemplateParameterList *Params = GetTemplateParameterList(Template);
6016
6017 SourceLocation RAngleLoc = NewArgs.getRAngleLoc();
6018
6019 // C++ [temp.arg]p1:
6020 // [...] The type and form of each template-argument specified in
6021 // a template-id shall match the type and form specified for the
6022 // corresponding parameter declared by the template in its
6023 // template-parameter-list.
6024 bool isTemplateTemplateParameter = isa<TemplateTemplateParmDecl>(Template);
6025 SmallVector<TemplateArgument, 2> SugaredArgumentPack;
6026 SmallVector<TemplateArgument, 2> CanonicalArgumentPack;
6027 unsigned ArgIdx = 0, NumArgs = NewArgs.size();
6028 LocalInstantiationScope InstScope(*this, true);
6029 for (TemplateParameterList::iterator Param = Params->begin(),
6030 ParamEnd = Params->end();
6031 Param != ParamEnd; /* increment in loop */) {
6032 // If we have an expanded parameter pack, make sure we don't have too
6033 // many arguments.
6034 if (std::optional<unsigned> Expansions = getExpandedPackSize(*Param)) {
6035 if (*Expansions == SugaredArgumentPack.size()) {
6036 // We're done with this parameter pack. Pack up its arguments and add
6037 // them to the list.
6038 SugaredConverted.push_back(
6039 TemplateArgument::CreatePackCopy(Context, SugaredArgumentPack));
6040 SugaredArgumentPack.clear();
6041
6042 CanonicalConverted.push_back(
6043 TemplateArgument::CreatePackCopy(Context, CanonicalArgumentPack));
6044 CanonicalArgumentPack.clear();
6045
6046 // This argument is assigned to the next parameter.
6047 ++Param;
6048 continue;
6049 } else if (ArgIdx == NumArgs && !PartialTemplateArgs) {
6050 // Not enough arguments for this parameter pack.
6051 Diag(TemplateLoc, diag::err_template_arg_list_different_arity)
6052 << /*not enough args*/0
6053 << (int)getTemplateNameKindForDiagnostics(TemplateName(Template))
6054 << Template;
6055 NoteTemplateLocation(*Template, Params->getSourceRange());
6056 return true;
6057 }
6058 }
6059
6060 if (ArgIdx < NumArgs) {
6061 // Check the template argument we were given.
6062 if (CheckTemplateArgument(*Param, NewArgs[ArgIdx], Template, TemplateLoc,
6063 RAngleLoc, SugaredArgumentPack.size(),
6064 SugaredConverted, CanonicalConverted,
6065 CTAK_Specified))
6066 return true;
6067
6068 CanonicalConverted.back().setIsDefaulted(
6069 clang::isSubstitutedDefaultArgument(
6070 Context, NewArgs[ArgIdx].getArgument(), *Param,
6071 CanonicalConverted, Params->getDepth()));
6072
6073 bool PackExpansionIntoNonPack =
6074 NewArgs[ArgIdx].getArgument().isPackExpansion() &&
6075 (!(*Param)->isTemplateParameterPack() || getExpandedPackSize(*Param));
6076 if (PackExpansionIntoNonPack && (isa<TypeAliasTemplateDecl>(Template) ||
6077 isa<ConceptDecl>(Template))) {
6078 // Core issue 1430: we have a pack expansion as an argument to an
6079 // alias template, and it's not part of a parameter pack. This
6080 // can't be canonicalized, so reject it now.
6081 // As for concepts - we cannot normalize constraints where this
6082 // situation exists.
6083 Diag(NewArgs[ArgIdx].getLocation(),
6084 diag::err_template_expansion_into_fixed_list)
6085 << (isa<ConceptDecl>(Template) ? 1 : 0)
6086 << NewArgs[ArgIdx].getSourceRange();
6087 NoteTemplateParameterLocation(**Param);
6088 return true;
6089 }
6090
6091 // We're now done with this argument.
6092 ++ArgIdx;
6093
6094 if ((*Param)->isTemplateParameterPack()) {
6095 // The template parameter was a template parameter pack, so take the
6096 // deduced argument and place it on the argument pack. Note that we
6097 // stay on the same template parameter so that we can deduce more
6098 // arguments.
6099 SugaredArgumentPack.push_back(SugaredConverted.pop_back_val());
6100 CanonicalArgumentPack.push_back(CanonicalConverted.pop_back_val());
6101 } else {
6102 // Move to the next template parameter.
6103 ++Param;
6104 }
6105
6106 // If we just saw a pack expansion into a non-pack, then directly convert
6107 // the remaining arguments, because we don't know what parameters they'll
6108 // match up with.
6109 if (PackExpansionIntoNonPack) {
6110 if (!SugaredArgumentPack.empty()) {
6111 // If we were part way through filling in an expanded parameter pack,
6112 // fall back to just producing individual arguments.
6113 SugaredConverted.insert(SugaredConverted.end(),
6114 SugaredArgumentPack.begin(),
6115 SugaredArgumentPack.end());
6116 SugaredArgumentPack.clear();
6117
6118 CanonicalConverted.insert(CanonicalConverted.end(),
6119 CanonicalArgumentPack.begin(),
6120 CanonicalArgumentPack.end());
6121 CanonicalArgumentPack.clear();
6122 }
6123
6124 while (ArgIdx < NumArgs) {
6125 const TemplateArgument &Arg = NewArgs[ArgIdx].getArgument();
6126 SugaredConverted.push_back(Arg);
6127 CanonicalConverted.push_back(
6128 Context.getCanonicalTemplateArgument(Arg));
6129 ++ArgIdx;
6130 }
6131
6132 return false;
6133 }
6134
6135 continue;
6136 }
6137
6138 // If we're checking a partial template argument list, we're done.
6139 if (PartialTemplateArgs) {
6140 if ((*Param)->isTemplateParameterPack() && !SugaredArgumentPack.empty()) {
6141 SugaredConverted.push_back(
6142 TemplateArgument::CreatePackCopy(Context, SugaredArgumentPack));
6143 CanonicalConverted.push_back(
6144 TemplateArgument::CreatePackCopy(Context, CanonicalArgumentPack));
6145 }
6146 return false;
6147 }
6148
6149 // If we have a template parameter pack with no more corresponding
6150 // arguments, just break out now and we'll fill in the argument pack below.
6151 if ((*Param)->isTemplateParameterPack()) {
6152 assert(!getExpandedPackSize(*Param) &&
6153 "Should have dealt with this already");
6154
6155 // A non-expanded parameter pack before the end of the parameter list
6156 // only occurs for an ill-formed template parameter list, unless we've
6157 // got a partial argument list for a function template, so just bail out.
6158 if (Param + 1 != ParamEnd) {
6159 assert(
6160 (Template->getMostRecentDecl()->getKind() != Decl::Kind::Concept) &&
6161 "Concept templates must have parameter packs at the end.");
6162 return true;
6163 }
6164
6165 SugaredConverted.push_back(
6166 TemplateArgument::CreatePackCopy(Context, SugaredArgumentPack));
6167 SugaredArgumentPack.clear();
6168
6169 CanonicalConverted.push_back(
6170 TemplateArgument::CreatePackCopy(Context, CanonicalArgumentPack));
6171 CanonicalArgumentPack.clear();
6172
6173 ++Param;
6174 continue;
6175 }
6176
6177 // Check whether we have a default argument.
6178 TemplateArgumentLoc Arg;
6179
6180 // Retrieve the default template argument from the template
6181 // parameter. For each kind of template parameter, we substitute the
6182 // template arguments provided thus far and any "outer" template arguments
6183 // (when the template parameter was part of a nested template) into
6184 // the default argument.
6185 if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(*Param)) {
6186 if (!hasReachableDefaultArgument(TTP))
6187 return diagnoseMissingArgument(*this, TemplateLoc, Template, TTP,
6188 NewArgs);
6189
6190 TypeSourceInfo *ArgType = SubstDefaultTemplateArgument(
6191 *this, Template, TemplateLoc, RAngleLoc, TTP, SugaredConverted,
6192 CanonicalConverted);
6193 if (!ArgType)
6194 return true;
6195
6196 Arg = TemplateArgumentLoc(TemplateArgument(ArgType->getType()),
6197 ArgType);
6198 } else if (NonTypeTemplateParmDecl *NTTP
6199 = dyn_cast<NonTypeTemplateParmDecl>(*Param)) {
6200 if (!hasReachableDefaultArgument(NTTP))
6201 return diagnoseMissingArgument(*this, TemplateLoc, Template, NTTP,
6202 NewArgs);
6203
6204 ExprResult E = SubstDefaultTemplateArgument(
6205 *this, Template, TemplateLoc, RAngleLoc, NTTP, SugaredConverted,
6206 CanonicalConverted);
6207 if (E.isInvalid())
6208 return true;
6209
6210 Expr *Ex = E.getAs<Expr>();
6211 Arg = TemplateArgumentLoc(TemplateArgument(Ex), Ex);
6212 } else {
6213 TemplateTemplateParmDecl *TempParm
6214 = cast<TemplateTemplateParmDecl>(*Param);
6215
6216 if (!hasReachableDefaultArgument(TempParm))
6217 return diagnoseMissingArgument(*this, TemplateLoc, Template, TempParm,
6218 NewArgs);
6219
6220 NestedNameSpecifierLoc QualifierLoc;
6221 TemplateName Name = SubstDefaultTemplateArgument(
6222 *this, Template, TemplateLoc, RAngleLoc, TempParm, SugaredConverted,
6223 CanonicalConverted, QualifierLoc);
6224 if (Name.isNull())
6225 return true;
6226
6227 Arg = TemplateArgumentLoc(
6228 Context, TemplateArgument(Name), QualifierLoc,
6229 TempParm->getDefaultArgument().getTemplateNameLoc());
6230 }
6231
6232 // Introduce an instantiation record that describes where we are using
6233 // the default template argument. We're not actually instantiating a
6234 // template here, we just create this object to put a note into the
6235 // context stack.
6236 InstantiatingTemplate Inst(*this, RAngleLoc, Template, *Param,
6237 SugaredConverted,
6238 SourceRange(TemplateLoc, RAngleLoc));
6239 if (Inst.isInvalid())
6240 return true;
6241
6242 // Check the default template argument.
6243 if (CheckTemplateArgument(*Param, Arg, Template, TemplateLoc, RAngleLoc, 0,
6244 SugaredConverted, CanonicalConverted,
6245 CTAK_Specified))
6246 return true;
6247
6248 CanonicalConverted.back().setIsDefaulted(true);
6249
6250 // Core issue 150 (assumed resolution): if this is a template template
6251 // parameter, keep track of the default template arguments from the
6252 // template definition.
6253 if (isTemplateTemplateParameter)
6254 NewArgs.addArgument(Arg);
6255
6256 // Move to the next template parameter and argument.
6257 ++Param;
6258 ++ArgIdx;
6259 }
6260
6261 // If we're performing a partial argument substitution, allow any trailing
6262 // pack expansions; they might be empty. This can happen even if
6263 // PartialTemplateArgs is false (the list of arguments is complete but
6264 // still dependent).
6265 if (ArgIdx < NumArgs && CurrentInstantiationScope &&
6266 CurrentInstantiationScope->getPartiallySubstitutedPack()) {
6267 while (ArgIdx < NumArgs &&
6268 NewArgs[ArgIdx].getArgument().isPackExpansion()) {
6269 const TemplateArgument &Arg = NewArgs[ArgIdx++].getArgument();
6270 SugaredConverted.push_back(Arg);
6271 CanonicalConverted.push_back(Context.getCanonicalTemplateArgument(Arg));
6272 }
6273 }
6274
6275 // If we have any leftover arguments, then there were too many arguments.
6276 // Complain and fail.
6277 if (ArgIdx < NumArgs) {
6278 Diag(TemplateLoc, diag::err_template_arg_list_different_arity)
6279 << /*too many args*/1
6280 << (int)getTemplateNameKindForDiagnostics(TemplateName(Template))
6281 << Template
6282 << SourceRange(NewArgs[ArgIdx].getLocation(), NewArgs.getRAngleLoc());
6283 NoteTemplateLocation(*Template, Params->getSourceRange());
6284 return true;
6285 }
6286
6287 // No problems found with the new argument list, propagate changes back
6288 // to caller.
6289 if (UpdateArgsWithConversions)
6290 TemplateArgs = std::move(NewArgs);
6291
6292 if (!PartialTemplateArgs) {
6293 TemplateArgumentList StackTemplateArgs(TemplateArgumentList::OnStack,
6294 CanonicalConverted);
6295 // Setup the context/ThisScope for the case where we are needing to
6296 // re-instantiate constraints outside of normal instantiation.
6297 DeclContext *NewContext = Template->getDeclContext();
6298
6299 // If this template is in a template, make sure we extract the templated
6300 // decl.
6301 if (auto *TD = dyn_cast<TemplateDecl>(NewContext))
6302 NewContext = Decl::castToDeclContext(TD->getTemplatedDecl());
6303 auto *RD = dyn_cast<CXXRecordDecl>(NewContext);
6304
6305 Qualifiers ThisQuals;
6306 if (const auto *Method =
6307 dyn_cast_or_null<CXXMethodDecl>(Template->getTemplatedDecl()))
6308 ThisQuals = Method->getMethodQualifiers();
6309
6310 ContextRAII Context(*this, NewContext);
6311 CXXThisScopeRAII(*this, RD, ThisQuals, RD != nullptr);
6312
6313 MultiLevelTemplateArgumentList MLTAL = getTemplateInstantiationArgs(
6314 Template, NewContext, /*Final=*/false, &StackTemplateArgs,
6315 /*RelativeToPrimary=*/true,
6316 /*Pattern=*/nullptr,
6317 /*ForConceptInstantiation=*/true);
6318 if (EnsureTemplateArgumentListConstraints(
6319 Template, MLTAL,
6320 SourceRange(TemplateLoc, TemplateArgs.getRAngleLoc()))) {
6321 if (ConstraintsNotSatisfied)
6322 *ConstraintsNotSatisfied = true;
6323 return true;
6324 }
6325 }
6326
6327 return false;
6328 }
6329
6330 namespace {
6331 class UnnamedLocalNoLinkageFinder
6332 : public TypeVisitor<UnnamedLocalNoLinkageFinder, bool>
6333 {
6334 Sema &S;
6335 SourceRange SR;
6336
6337 typedef TypeVisitor<UnnamedLocalNoLinkageFinder, bool> inherited;
6338
6339 public:
UnnamedLocalNoLinkageFinder(Sema & S,SourceRange SR)6340 UnnamedLocalNoLinkageFinder(Sema &S, SourceRange SR) : S(S), SR(SR) { }
6341
Visit(QualType T)6342 bool Visit(QualType T) {
6343 return T.isNull() ? false : inherited::Visit(T.getTypePtr());
6344 }
6345
6346 #define TYPE(Class, Parent) \
6347 bool Visit##Class##Type(const Class##Type *);
6348 #define ABSTRACT_TYPE(Class, Parent) \
6349 bool Visit##Class##Type(const Class##Type *) { return false; }
6350 #define NON_CANONICAL_TYPE(Class, Parent) \
6351 bool Visit##Class##Type(const Class##Type *) { return false; }
6352 #include "clang/AST/TypeNodes.inc"
6353
6354 bool VisitTagDecl(const TagDecl *Tag);
6355 bool VisitNestedNameSpecifier(NestedNameSpecifier *NNS);
6356 };
6357 } // end anonymous namespace
6358
VisitBuiltinType(const BuiltinType *)6359 bool UnnamedLocalNoLinkageFinder::VisitBuiltinType(const BuiltinType*) {
6360 return false;
6361 }
6362
VisitComplexType(const ComplexType * T)6363 bool UnnamedLocalNoLinkageFinder::VisitComplexType(const ComplexType* T) {
6364 return Visit(T->getElementType());
6365 }
6366
VisitPointerType(const PointerType * T)6367 bool UnnamedLocalNoLinkageFinder::VisitPointerType(const PointerType* T) {
6368 return Visit(T->getPointeeType());
6369 }
6370
VisitBlockPointerType(const BlockPointerType * T)6371 bool UnnamedLocalNoLinkageFinder::VisitBlockPointerType(
6372 const BlockPointerType* T) {
6373 return Visit(T->getPointeeType());
6374 }
6375
VisitLValueReferenceType(const LValueReferenceType * T)6376 bool UnnamedLocalNoLinkageFinder::VisitLValueReferenceType(
6377 const LValueReferenceType* T) {
6378 return Visit(T->getPointeeType());
6379 }
6380
VisitRValueReferenceType(const RValueReferenceType * T)6381 bool UnnamedLocalNoLinkageFinder::VisitRValueReferenceType(
6382 const RValueReferenceType* T) {
6383 return Visit(T->getPointeeType());
6384 }
6385
VisitMemberPointerType(const MemberPointerType * T)6386 bool UnnamedLocalNoLinkageFinder::VisitMemberPointerType(
6387 const MemberPointerType* T) {
6388 return Visit(T->getPointeeType()) || Visit(QualType(T->getClass(), 0));
6389 }
6390
VisitConstantArrayType(const ConstantArrayType * T)6391 bool UnnamedLocalNoLinkageFinder::VisitConstantArrayType(
6392 const ConstantArrayType* T) {
6393 return Visit(T->getElementType());
6394 }
6395
VisitIncompleteArrayType(const IncompleteArrayType * T)6396 bool UnnamedLocalNoLinkageFinder::VisitIncompleteArrayType(
6397 const IncompleteArrayType* T) {
6398 return Visit(T->getElementType());
6399 }
6400
VisitVariableArrayType(const VariableArrayType * T)6401 bool UnnamedLocalNoLinkageFinder::VisitVariableArrayType(
6402 const VariableArrayType* T) {
6403 return Visit(T->getElementType());
6404 }
6405
VisitDependentSizedArrayType(const DependentSizedArrayType * T)6406 bool UnnamedLocalNoLinkageFinder::VisitDependentSizedArrayType(
6407 const DependentSizedArrayType* T) {
6408 return Visit(T->getElementType());
6409 }
6410
VisitDependentSizedExtVectorType(const DependentSizedExtVectorType * T)6411 bool UnnamedLocalNoLinkageFinder::VisitDependentSizedExtVectorType(
6412 const DependentSizedExtVectorType* T) {
6413 return Visit(T->getElementType());
6414 }
6415
VisitDependentSizedMatrixType(const DependentSizedMatrixType * T)6416 bool UnnamedLocalNoLinkageFinder::VisitDependentSizedMatrixType(
6417 const DependentSizedMatrixType *T) {
6418 return Visit(T->getElementType());
6419 }
6420
VisitDependentAddressSpaceType(const DependentAddressSpaceType * T)6421 bool UnnamedLocalNoLinkageFinder::VisitDependentAddressSpaceType(
6422 const DependentAddressSpaceType *T) {
6423 return Visit(T->getPointeeType());
6424 }
6425
VisitVectorType(const VectorType * T)6426 bool UnnamedLocalNoLinkageFinder::VisitVectorType(const VectorType* T) {
6427 return Visit(T->getElementType());
6428 }
6429
VisitDependentVectorType(const DependentVectorType * T)6430 bool UnnamedLocalNoLinkageFinder::VisitDependentVectorType(
6431 const DependentVectorType *T) {
6432 return Visit(T->getElementType());
6433 }
6434
VisitExtVectorType(const ExtVectorType * T)6435 bool UnnamedLocalNoLinkageFinder::VisitExtVectorType(const ExtVectorType* T) {
6436 return Visit(T->getElementType());
6437 }
6438
VisitConstantMatrixType(const ConstantMatrixType * T)6439 bool UnnamedLocalNoLinkageFinder::VisitConstantMatrixType(
6440 const ConstantMatrixType *T) {
6441 return Visit(T->getElementType());
6442 }
6443
VisitFunctionProtoType(const FunctionProtoType * T)6444 bool UnnamedLocalNoLinkageFinder::VisitFunctionProtoType(
6445 const FunctionProtoType* T) {
6446 for (const auto &A : T->param_types()) {
6447 if (Visit(A))
6448 return true;
6449 }
6450
6451 return Visit(T->getReturnType());
6452 }
6453
VisitFunctionNoProtoType(const FunctionNoProtoType * T)6454 bool UnnamedLocalNoLinkageFinder::VisitFunctionNoProtoType(
6455 const FunctionNoProtoType* T) {
6456 return Visit(T->getReturnType());
6457 }
6458
VisitUnresolvedUsingType(const UnresolvedUsingType *)6459 bool UnnamedLocalNoLinkageFinder::VisitUnresolvedUsingType(
6460 const UnresolvedUsingType*) {
6461 return false;
6462 }
6463
VisitTypeOfExprType(const TypeOfExprType *)6464 bool UnnamedLocalNoLinkageFinder::VisitTypeOfExprType(const TypeOfExprType*) {
6465 return false;
6466 }
6467
VisitTypeOfType(const TypeOfType * T)6468 bool UnnamedLocalNoLinkageFinder::VisitTypeOfType(const TypeOfType* T) {
6469 return Visit(T->getUnmodifiedType());
6470 }
6471
VisitDecltypeType(const DecltypeType *)6472 bool UnnamedLocalNoLinkageFinder::VisitDecltypeType(const DecltypeType*) {
6473 return false;
6474 }
6475
VisitUnaryTransformType(const UnaryTransformType *)6476 bool UnnamedLocalNoLinkageFinder::VisitUnaryTransformType(
6477 const UnaryTransformType*) {
6478 return false;
6479 }
6480
VisitAutoType(const AutoType * T)6481 bool UnnamedLocalNoLinkageFinder::VisitAutoType(const AutoType *T) {
6482 return Visit(T->getDeducedType());
6483 }
6484
VisitDeducedTemplateSpecializationType(const DeducedTemplateSpecializationType * T)6485 bool UnnamedLocalNoLinkageFinder::VisitDeducedTemplateSpecializationType(
6486 const DeducedTemplateSpecializationType *T) {
6487 return Visit(T->getDeducedType());
6488 }
6489
VisitRecordType(const RecordType * T)6490 bool UnnamedLocalNoLinkageFinder::VisitRecordType(const RecordType* T) {
6491 return VisitTagDecl(T->getDecl());
6492 }
6493
VisitEnumType(const EnumType * T)6494 bool UnnamedLocalNoLinkageFinder::VisitEnumType(const EnumType* T) {
6495 return VisitTagDecl(T->getDecl());
6496 }
6497
VisitTemplateTypeParmType(const TemplateTypeParmType *)6498 bool UnnamedLocalNoLinkageFinder::VisitTemplateTypeParmType(
6499 const TemplateTypeParmType*) {
6500 return false;
6501 }
6502
VisitSubstTemplateTypeParmPackType(const SubstTemplateTypeParmPackType *)6503 bool UnnamedLocalNoLinkageFinder::VisitSubstTemplateTypeParmPackType(
6504 const SubstTemplateTypeParmPackType *) {
6505 return false;
6506 }
6507
VisitTemplateSpecializationType(const TemplateSpecializationType *)6508 bool UnnamedLocalNoLinkageFinder::VisitTemplateSpecializationType(
6509 const TemplateSpecializationType*) {
6510 return false;
6511 }
6512
VisitInjectedClassNameType(const InjectedClassNameType * T)6513 bool UnnamedLocalNoLinkageFinder::VisitInjectedClassNameType(
6514 const InjectedClassNameType* T) {
6515 return VisitTagDecl(T->getDecl());
6516 }
6517
VisitDependentNameType(const DependentNameType * T)6518 bool UnnamedLocalNoLinkageFinder::VisitDependentNameType(
6519 const DependentNameType* T) {
6520 return VisitNestedNameSpecifier(T->getQualifier());
6521 }
6522
VisitDependentTemplateSpecializationType(const DependentTemplateSpecializationType * T)6523 bool UnnamedLocalNoLinkageFinder::VisitDependentTemplateSpecializationType(
6524 const DependentTemplateSpecializationType* T) {
6525 if (auto *Q = T->getQualifier())
6526 return VisitNestedNameSpecifier(Q);
6527 return false;
6528 }
6529
VisitPackExpansionType(const PackExpansionType * T)6530 bool UnnamedLocalNoLinkageFinder::VisitPackExpansionType(
6531 const PackExpansionType* T) {
6532 return Visit(T->getPattern());
6533 }
6534
VisitObjCObjectType(const ObjCObjectType *)6535 bool UnnamedLocalNoLinkageFinder::VisitObjCObjectType(const ObjCObjectType *) {
6536 return false;
6537 }
6538
VisitObjCInterfaceType(const ObjCInterfaceType *)6539 bool UnnamedLocalNoLinkageFinder::VisitObjCInterfaceType(
6540 const ObjCInterfaceType *) {
6541 return false;
6542 }
6543
VisitObjCObjectPointerType(const ObjCObjectPointerType *)6544 bool UnnamedLocalNoLinkageFinder::VisitObjCObjectPointerType(
6545 const ObjCObjectPointerType *) {
6546 return false;
6547 }
6548
VisitAtomicType(const AtomicType * T)6549 bool UnnamedLocalNoLinkageFinder::VisitAtomicType(const AtomicType* T) {
6550 return Visit(T->getValueType());
6551 }
6552
VisitPipeType(const PipeType * T)6553 bool UnnamedLocalNoLinkageFinder::VisitPipeType(const PipeType* T) {
6554 return false;
6555 }
6556
VisitBitIntType(const BitIntType * T)6557 bool UnnamedLocalNoLinkageFinder::VisitBitIntType(const BitIntType *T) {
6558 return false;
6559 }
6560
VisitDependentBitIntType(const DependentBitIntType * T)6561 bool UnnamedLocalNoLinkageFinder::VisitDependentBitIntType(
6562 const DependentBitIntType *T) {
6563 return false;
6564 }
6565
VisitTagDecl(const TagDecl * Tag)6566 bool UnnamedLocalNoLinkageFinder::VisitTagDecl(const TagDecl *Tag) {
6567 if (Tag->getDeclContext()->isFunctionOrMethod()) {
6568 S.Diag(SR.getBegin(),
6569 S.getLangOpts().CPlusPlus11 ?
6570 diag::warn_cxx98_compat_template_arg_local_type :
6571 diag::ext_template_arg_local_type)
6572 << S.Context.getTypeDeclType(Tag) << SR;
6573 return true;
6574 }
6575
6576 if (!Tag->hasNameForLinkage()) {
6577 S.Diag(SR.getBegin(),
6578 S.getLangOpts().CPlusPlus11 ?
6579 diag::warn_cxx98_compat_template_arg_unnamed_type :
6580 diag::ext_template_arg_unnamed_type) << SR;
6581 S.Diag(Tag->getLocation(), diag::note_template_unnamed_type_here);
6582 return true;
6583 }
6584
6585 return false;
6586 }
6587
VisitNestedNameSpecifier(NestedNameSpecifier * NNS)6588 bool UnnamedLocalNoLinkageFinder::VisitNestedNameSpecifier(
6589 NestedNameSpecifier *NNS) {
6590 assert(NNS);
6591 if (NNS->getPrefix() && VisitNestedNameSpecifier(NNS->getPrefix()))
6592 return true;
6593
6594 switch (NNS->getKind()) {
6595 case NestedNameSpecifier::Identifier:
6596 case NestedNameSpecifier::Namespace:
6597 case NestedNameSpecifier::NamespaceAlias:
6598 case NestedNameSpecifier::Global:
6599 case NestedNameSpecifier::Super:
6600 return false;
6601
6602 case NestedNameSpecifier::TypeSpec:
6603 case NestedNameSpecifier::TypeSpecWithTemplate:
6604 return Visit(QualType(NNS->getAsType(), 0));
6605 }
6606 llvm_unreachable("Invalid NestedNameSpecifier::Kind!");
6607 }
6608
6609 /// Check a template argument against its corresponding
6610 /// template type parameter.
6611 ///
6612 /// This routine implements the semantics of C++ [temp.arg.type]. It
6613 /// returns true if an error occurred, and false otherwise.
CheckTemplateArgument(TypeSourceInfo * ArgInfo)6614 bool Sema::CheckTemplateArgument(TypeSourceInfo *ArgInfo) {
6615 assert(ArgInfo && "invalid TypeSourceInfo");
6616 QualType Arg = ArgInfo->getType();
6617 SourceRange SR = ArgInfo->getTypeLoc().getSourceRange();
6618 QualType CanonArg = Context.getCanonicalType(Arg);
6619
6620 if (CanonArg->isVariablyModifiedType()) {
6621 return Diag(SR.getBegin(), diag::err_variably_modified_template_arg) << Arg;
6622 } else if (Context.hasSameUnqualifiedType(Arg, Context.OverloadTy)) {
6623 return Diag(SR.getBegin(), diag::err_template_arg_overload_type) << SR;
6624 }
6625
6626 // C++03 [temp.arg.type]p2:
6627 // A local type, a type with no linkage, an unnamed type or a type
6628 // compounded from any of these types shall not be used as a
6629 // template-argument for a template type-parameter.
6630 //
6631 // C++11 allows these, and even in C++03 we allow them as an extension with
6632 // a warning.
6633 if (LangOpts.CPlusPlus11 || CanonArg->hasUnnamedOrLocalType()) {
6634 UnnamedLocalNoLinkageFinder Finder(*this, SR);
6635 (void)Finder.Visit(CanonArg);
6636 }
6637
6638 return false;
6639 }
6640
6641 enum NullPointerValueKind {
6642 NPV_NotNullPointer,
6643 NPV_NullPointer,
6644 NPV_Error
6645 };
6646
6647 /// Determine whether the given template argument is a null pointer
6648 /// value of the appropriate type.
6649 static NullPointerValueKind
isNullPointerValueTemplateArgument(Sema & S,NonTypeTemplateParmDecl * Param,QualType ParamType,Expr * Arg,Decl * Entity=nullptr)6650 isNullPointerValueTemplateArgument(Sema &S, NonTypeTemplateParmDecl *Param,
6651 QualType ParamType, Expr *Arg,
6652 Decl *Entity = nullptr) {
6653 if (Arg->isValueDependent() || Arg->isTypeDependent())
6654 return NPV_NotNullPointer;
6655
6656 // dllimport'd entities aren't constant but are available inside of template
6657 // arguments.
6658 if (Entity && Entity->hasAttr<DLLImportAttr>())
6659 return NPV_NotNullPointer;
6660
6661 if (!S.isCompleteType(Arg->getExprLoc(), ParamType))
6662 llvm_unreachable(
6663 "Incomplete parameter type in isNullPointerValueTemplateArgument!");
6664
6665 if (!S.getLangOpts().CPlusPlus11)
6666 return NPV_NotNullPointer;
6667
6668 // Determine whether we have a constant expression.
6669 ExprResult ArgRV = S.DefaultFunctionArrayConversion(Arg);
6670 if (ArgRV.isInvalid())
6671 return NPV_Error;
6672 Arg = ArgRV.get();
6673
6674 Expr::EvalResult EvalResult;
6675 SmallVector<PartialDiagnosticAt, 8> Notes;
6676 EvalResult.Diag = &Notes;
6677 if (!Arg->EvaluateAsRValue(EvalResult, S.Context) ||
6678 EvalResult.HasSideEffects) {
6679 SourceLocation DiagLoc = Arg->getExprLoc();
6680
6681 // If our only note is the usual "invalid subexpression" note, just point
6682 // the caret at its location rather than producing an essentially
6683 // redundant note.
6684 if (Notes.size() == 1 && Notes[0].second.getDiagID() ==
6685 diag::note_invalid_subexpr_in_const_expr) {
6686 DiagLoc = Notes[0].first;
6687 Notes.clear();
6688 }
6689
6690 S.Diag(DiagLoc, diag::err_template_arg_not_address_constant)
6691 << Arg->getType() << Arg->getSourceRange();
6692 for (unsigned I = 0, N = Notes.size(); I != N; ++I)
6693 S.Diag(Notes[I].first, Notes[I].second);
6694
6695 S.NoteTemplateParameterLocation(*Param);
6696 return NPV_Error;
6697 }
6698
6699 // C++11 [temp.arg.nontype]p1:
6700 // - an address constant expression of type std::nullptr_t
6701 if (Arg->getType()->isNullPtrType())
6702 return NPV_NullPointer;
6703
6704 // - a constant expression that evaluates to a null pointer value (4.10); or
6705 // - a constant expression that evaluates to a null member pointer value
6706 // (4.11); or
6707 if ((EvalResult.Val.isLValue() && EvalResult.Val.isNullPointer()) ||
6708 (EvalResult.Val.isMemberPointer() &&
6709 !EvalResult.Val.getMemberPointerDecl())) {
6710 // If our expression has an appropriate type, we've succeeded.
6711 bool ObjCLifetimeConversion;
6712 if (S.Context.hasSameUnqualifiedType(Arg->getType(), ParamType) ||
6713 S.IsQualificationConversion(Arg->getType(), ParamType, false,
6714 ObjCLifetimeConversion))
6715 return NPV_NullPointer;
6716
6717 // The types didn't match, but we know we got a null pointer; complain,
6718 // then recover as if the types were correct.
6719 S.Diag(Arg->getExprLoc(), diag::err_template_arg_wrongtype_null_constant)
6720 << Arg->getType() << ParamType << Arg->getSourceRange();
6721 S.NoteTemplateParameterLocation(*Param);
6722 return NPV_NullPointer;
6723 }
6724
6725 if (EvalResult.Val.isLValue() && !EvalResult.Val.getLValueBase()) {
6726 // We found a pointer that isn't null, but doesn't refer to an object.
6727 // We could just return NPV_NotNullPointer, but we can print a better
6728 // message with the information we have here.
6729 S.Diag(Arg->getExprLoc(), diag::err_template_arg_invalid)
6730 << EvalResult.Val.getAsString(S.Context, ParamType);
6731 S.NoteTemplateParameterLocation(*Param);
6732 return NPV_Error;
6733 }
6734
6735 // If we don't have a null pointer value, but we do have a NULL pointer
6736 // constant, suggest a cast to the appropriate type.
6737 if (Arg->isNullPointerConstant(S.Context, Expr::NPC_NeverValueDependent)) {
6738 std::string Code = "static_cast<" + ParamType.getAsString() + ">(";
6739 S.Diag(Arg->getExprLoc(), diag::err_template_arg_untyped_null_constant)
6740 << ParamType << FixItHint::CreateInsertion(Arg->getBeginLoc(), Code)
6741 << FixItHint::CreateInsertion(S.getLocForEndOfToken(Arg->getEndLoc()),
6742 ")");
6743 S.NoteTemplateParameterLocation(*Param);
6744 return NPV_NullPointer;
6745 }
6746
6747 // FIXME: If we ever want to support general, address-constant expressions
6748 // as non-type template arguments, we should return the ExprResult here to
6749 // be interpreted by the caller.
6750 return NPV_NotNullPointer;
6751 }
6752
6753 /// Checks whether the given template argument is compatible with its
6754 /// template parameter.
CheckTemplateArgumentIsCompatibleWithParameter(Sema & S,NonTypeTemplateParmDecl * Param,QualType ParamType,Expr * ArgIn,Expr * Arg,QualType ArgType)6755 static bool CheckTemplateArgumentIsCompatibleWithParameter(
6756 Sema &S, NonTypeTemplateParmDecl *Param, QualType ParamType, Expr *ArgIn,
6757 Expr *Arg, QualType ArgType) {
6758 bool ObjCLifetimeConversion;
6759 if (ParamType->isPointerType() &&
6760 !ParamType->castAs<PointerType>()->getPointeeType()->isFunctionType() &&
6761 S.IsQualificationConversion(ArgType, ParamType, false,
6762 ObjCLifetimeConversion)) {
6763 // For pointer-to-object types, qualification conversions are
6764 // permitted.
6765 } else {
6766 if (const ReferenceType *ParamRef = ParamType->getAs<ReferenceType>()) {
6767 if (!ParamRef->getPointeeType()->isFunctionType()) {
6768 // C++ [temp.arg.nontype]p5b3:
6769 // For a non-type template-parameter of type reference to
6770 // object, no conversions apply. The type referred to by the
6771 // reference may be more cv-qualified than the (otherwise
6772 // identical) type of the template- argument. The
6773 // template-parameter is bound directly to the
6774 // template-argument, which shall be an lvalue.
6775
6776 // FIXME: Other qualifiers?
6777 unsigned ParamQuals = ParamRef->getPointeeType().getCVRQualifiers();
6778 unsigned ArgQuals = ArgType.getCVRQualifiers();
6779
6780 if ((ParamQuals | ArgQuals) != ParamQuals) {
6781 S.Diag(Arg->getBeginLoc(),
6782 diag::err_template_arg_ref_bind_ignores_quals)
6783 << ParamType << Arg->getType() << Arg->getSourceRange();
6784 S.NoteTemplateParameterLocation(*Param);
6785 return true;
6786 }
6787 }
6788 }
6789
6790 // At this point, the template argument refers to an object or
6791 // function with external linkage. We now need to check whether the
6792 // argument and parameter types are compatible.
6793 if (!S.Context.hasSameUnqualifiedType(ArgType,
6794 ParamType.getNonReferenceType())) {
6795 // We can't perform this conversion or binding.
6796 if (ParamType->isReferenceType())
6797 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_no_ref_bind)
6798 << ParamType << ArgIn->getType() << Arg->getSourceRange();
6799 else
6800 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_not_convertible)
6801 << ArgIn->getType() << ParamType << Arg->getSourceRange();
6802 S.NoteTemplateParameterLocation(*Param);
6803 return true;
6804 }
6805 }
6806
6807 return false;
6808 }
6809
6810 /// Checks whether the given template argument is the address
6811 /// of an object or function according to C++ [temp.arg.nontype]p1.
CheckTemplateArgumentAddressOfObjectOrFunction(Sema & S,NonTypeTemplateParmDecl * Param,QualType ParamType,Expr * ArgIn,TemplateArgument & SugaredConverted,TemplateArgument & CanonicalConverted)6812 static bool CheckTemplateArgumentAddressOfObjectOrFunction(
6813 Sema &S, NonTypeTemplateParmDecl *Param, QualType ParamType, Expr *ArgIn,
6814 TemplateArgument &SugaredConverted, TemplateArgument &CanonicalConverted) {
6815 bool Invalid = false;
6816 Expr *Arg = ArgIn;
6817 QualType ArgType = Arg->getType();
6818
6819 bool AddressTaken = false;
6820 SourceLocation AddrOpLoc;
6821 if (S.getLangOpts().MicrosoftExt) {
6822 // Microsoft Visual C++ strips all casts, allows an arbitrary number of
6823 // dereference and address-of operators.
6824 Arg = Arg->IgnoreParenCasts();
6825
6826 bool ExtWarnMSTemplateArg = false;
6827 UnaryOperatorKind FirstOpKind;
6828 SourceLocation FirstOpLoc;
6829 while (UnaryOperator *UnOp = dyn_cast<UnaryOperator>(Arg)) {
6830 UnaryOperatorKind UnOpKind = UnOp->getOpcode();
6831 if (UnOpKind == UO_Deref)
6832 ExtWarnMSTemplateArg = true;
6833 if (UnOpKind == UO_AddrOf || UnOpKind == UO_Deref) {
6834 Arg = UnOp->getSubExpr()->IgnoreParenCasts();
6835 if (!AddrOpLoc.isValid()) {
6836 FirstOpKind = UnOpKind;
6837 FirstOpLoc = UnOp->getOperatorLoc();
6838 }
6839 } else
6840 break;
6841 }
6842 if (FirstOpLoc.isValid()) {
6843 if (ExtWarnMSTemplateArg)
6844 S.Diag(ArgIn->getBeginLoc(), diag::ext_ms_deref_template_argument)
6845 << ArgIn->getSourceRange();
6846
6847 if (FirstOpKind == UO_AddrOf)
6848 AddressTaken = true;
6849 else if (Arg->getType()->isPointerType()) {
6850 // We cannot let pointers get dereferenced here, that is obviously not a
6851 // constant expression.
6852 assert(FirstOpKind == UO_Deref);
6853 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_not_decl_ref)
6854 << Arg->getSourceRange();
6855 }
6856 }
6857 } else {
6858 // See through any implicit casts we added to fix the type.
6859 Arg = Arg->IgnoreImpCasts();
6860
6861 // C++ [temp.arg.nontype]p1:
6862 //
6863 // A template-argument for a non-type, non-template
6864 // template-parameter shall be one of: [...]
6865 //
6866 // -- the address of an object or function with external
6867 // linkage, including function templates and function
6868 // template-ids but excluding non-static class members,
6869 // expressed as & id-expression where the & is optional if
6870 // the name refers to a function or array, or if the
6871 // corresponding template-parameter is a reference; or
6872
6873 // In C++98/03 mode, give an extension warning on any extra parentheses.
6874 // See http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#773
6875 bool ExtraParens = false;
6876 while (ParenExpr *Parens = dyn_cast<ParenExpr>(Arg)) {
6877 if (!Invalid && !ExtraParens) {
6878 S.Diag(Arg->getBeginLoc(),
6879 S.getLangOpts().CPlusPlus11
6880 ? diag::warn_cxx98_compat_template_arg_extra_parens
6881 : diag::ext_template_arg_extra_parens)
6882 << Arg->getSourceRange();
6883 ExtraParens = true;
6884 }
6885
6886 Arg = Parens->getSubExpr();
6887 }
6888
6889 while (SubstNonTypeTemplateParmExpr *subst =
6890 dyn_cast<SubstNonTypeTemplateParmExpr>(Arg))
6891 Arg = subst->getReplacement()->IgnoreImpCasts();
6892
6893 if (UnaryOperator *UnOp = dyn_cast<UnaryOperator>(Arg)) {
6894 if (UnOp->getOpcode() == UO_AddrOf) {
6895 Arg = UnOp->getSubExpr();
6896 AddressTaken = true;
6897 AddrOpLoc = UnOp->getOperatorLoc();
6898 }
6899 }
6900
6901 while (SubstNonTypeTemplateParmExpr *subst =
6902 dyn_cast<SubstNonTypeTemplateParmExpr>(Arg))
6903 Arg = subst->getReplacement()->IgnoreImpCasts();
6904 }
6905
6906 ValueDecl *Entity = nullptr;
6907 if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Arg))
6908 Entity = DRE->getDecl();
6909 else if (CXXUuidofExpr *CUE = dyn_cast<CXXUuidofExpr>(Arg))
6910 Entity = CUE->getGuidDecl();
6911
6912 // If our parameter has pointer type, check for a null template value.
6913 if (ParamType->isPointerType() || ParamType->isNullPtrType()) {
6914 switch (isNullPointerValueTemplateArgument(S, Param, ParamType, ArgIn,
6915 Entity)) {
6916 case NPV_NullPointer:
6917 S.Diag(Arg->getExprLoc(), diag::warn_cxx98_compat_template_arg_null);
6918 SugaredConverted = TemplateArgument(ParamType,
6919 /*isNullPtr=*/true);
6920 CanonicalConverted =
6921 TemplateArgument(S.Context.getCanonicalType(ParamType),
6922 /*isNullPtr=*/true);
6923 return false;
6924
6925 case NPV_Error:
6926 return true;
6927
6928 case NPV_NotNullPointer:
6929 break;
6930 }
6931 }
6932
6933 // Stop checking the precise nature of the argument if it is value dependent,
6934 // it should be checked when instantiated.
6935 if (Arg->isValueDependent()) {
6936 SugaredConverted = TemplateArgument(ArgIn);
6937 CanonicalConverted =
6938 S.Context.getCanonicalTemplateArgument(SugaredConverted);
6939 return false;
6940 }
6941
6942 if (!Entity) {
6943 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_not_decl_ref)
6944 << Arg->getSourceRange();
6945 S.NoteTemplateParameterLocation(*Param);
6946 return true;
6947 }
6948
6949 // Cannot refer to non-static data members
6950 if (isa<FieldDecl>(Entity) || isa<IndirectFieldDecl>(Entity)) {
6951 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_field)
6952 << Entity << Arg->getSourceRange();
6953 S.NoteTemplateParameterLocation(*Param);
6954 return true;
6955 }
6956
6957 // Cannot refer to non-static member functions
6958 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Entity)) {
6959 if (!Method->isStatic()) {
6960 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_method)
6961 << Method << Arg->getSourceRange();
6962 S.NoteTemplateParameterLocation(*Param);
6963 return true;
6964 }
6965 }
6966
6967 FunctionDecl *Func = dyn_cast<FunctionDecl>(Entity);
6968 VarDecl *Var = dyn_cast<VarDecl>(Entity);
6969 MSGuidDecl *Guid = dyn_cast<MSGuidDecl>(Entity);
6970
6971 // A non-type template argument must refer to an object or function.
6972 if (!Func && !Var && !Guid) {
6973 // We found something, but we don't know specifically what it is.
6974 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_not_object_or_func)
6975 << Arg->getSourceRange();
6976 S.Diag(Entity->getLocation(), diag::note_template_arg_refers_here);
6977 return true;
6978 }
6979
6980 // Address / reference template args must have external linkage in C++98.
6981 if (Entity->getFormalLinkage() == Linkage::Internal) {
6982 S.Diag(Arg->getBeginLoc(),
6983 S.getLangOpts().CPlusPlus11
6984 ? diag::warn_cxx98_compat_template_arg_object_internal
6985 : diag::ext_template_arg_object_internal)
6986 << !Func << Entity << Arg->getSourceRange();
6987 S.Diag(Entity->getLocation(), diag::note_template_arg_internal_object)
6988 << !Func;
6989 } else if (!Entity->hasLinkage()) {
6990 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_object_no_linkage)
6991 << !Func << Entity << Arg->getSourceRange();
6992 S.Diag(Entity->getLocation(), diag::note_template_arg_internal_object)
6993 << !Func;
6994 return true;
6995 }
6996
6997 if (Var) {
6998 // A value of reference type is not an object.
6999 if (Var->getType()->isReferenceType()) {
7000 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_reference_var)
7001 << Var->getType() << Arg->getSourceRange();
7002 S.NoteTemplateParameterLocation(*Param);
7003 return true;
7004 }
7005
7006 // A template argument must have static storage duration.
7007 if (Var->getTLSKind()) {
7008 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_thread_local)
7009 << Arg->getSourceRange();
7010 S.Diag(Var->getLocation(), diag::note_template_arg_refers_here);
7011 return true;
7012 }
7013 }
7014
7015 if (AddressTaken && ParamType->isReferenceType()) {
7016 // If we originally had an address-of operator, but the
7017 // parameter has reference type, complain and (if things look
7018 // like they will work) drop the address-of operator.
7019 if (!S.Context.hasSameUnqualifiedType(Entity->getType(),
7020 ParamType.getNonReferenceType())) {
7021 S.Diag(AddrOpLoc, diag::err_template_arg_address_of_non_pointer)
7022 << ParamType;
7023 S.NoteTemplateParameterLocation(*Param);
7024 return true;
7025 }
7026
7027 S.Diag(AddrOpLoc, diag::err_template_arg_address_of_non_pointer)
7028 << ParamType
7029 << FixItHint::CreateRemoval(AddrOpLoc);
7030 S.NoteTemplateParameterLocation(*Param);
7031
7032 ArgType = Entity->getType();
7033 }
7034
7035 // If the template parameter has pointer type, either we must have taken the
7036 // address or the argument must decay to a pointer.
7037 if (!AddressTaken && ParamType->isPointerType()) {
7038 if (Func) {
7039 // Function-to-pointer decay.
7040 ArgType = S.Context.getPointerType(Func->getType());
7041 } else if (Entity->getType()->isArrayType()) {
7042 // Array-to-pointer decay.
7043 ArgType = S.Context.getArrayDecayedType(Entity->getType());
7044 } else {
7045 // If the template parameter has pointer type but the address of
7046 // this object was not taken, complain and (possibly) recover by
7047 // taking the address of the entity.
7048 ArgType = S.Context.getPointerType(Entity->getType());
7049 if (!S.Context.hasSameUnqualifiedType(ArgType, ParamType)) {
7050 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_not_address_of)
7051 << ParamType;
7052 S.NoteTemplateParameterLocation(*Param);
7053 return true;
7054 }
7055
7056 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_not_address_of)
7057 << ParamType << FixItHint::CreateInsertion(Arg->getBeginLoc(), "&");
7058
7059 S.NoteTemplateParameterLocation(*Param);
7060 }
7061 }
7062
7063 if (CheckTemplateArgumentIsCompatibleWithParameter(S, Param, ParamType, ArgIn,
7064 Arg, ArgType))
7065 return true;
7066
7067 // Create the template argument.
7068 SugaredConverted = TemplateArgument(Entity, ParamType);
7069 CanonicalConverted =
7070 TemplateArgument(cast<ValueDecl>(Entity->getCanonicalDecl()),
7071 S.Context.getCanonicalType(ParamType));
7072 S.MarkAnyDeclReferenced(Arg->getBeginLoc(), Entity, false);
7073 return false;
7074 }
7075
7076 /// Checks whether the given template argument is a pointer to
7077 /// member constant according to C++ [temp.arg.nontype]p1.
7078 static bool
CheckTemplateArgumentPointerToMember(Sema & S,NonTypeTemplateParmDecl * Param,QualType ParamType,Expr * & ResultArg,TemplateArgument & SugaredConverted,TemplateArgument & CanonicalConverted)7079 CheckTemplateArgumentPointerToMember(Sema &S, NonTypeTemplateParmDecl *Param,
7080 QualType ParamType, Expr *&ResultArg,
7081 TemplateArgument &SugaredConverted,
7082 TemplateArgument &CanonicalConverted) {
7083 bool Invalid = false;
7084
7085 Expr *Arg = ResultArg;
7086 bool ObjCLifetimeConversion;
7087
7088 // C++ [temp.arg.nontype]p1:
7089 //
7090 // A template-argument for a non-type, non-template
7091 // template-parameter shall be one of: [...]
7092 //
7093 // -- a pointer to member expressed as described in 5.3.1.
7094 DeclRefExpr *DRE = nullptr;
7095
7096 // In C++98/03 mode, give an extension warning on any extra parentheses.
7097 // See http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#773
7098 bool ExtraParens = false;
7099 while (ParenExpr *Parens = dyn_cast<ParenExpr>(Arg)) {
7100 if (!Invalid && !ExtraParens) {
7101 S.Diag(Arg->getBeginLoc(),
7102 S.getLangOpts().CPlusPlus11
7103 ? diag::warn_cxx98_compat_template_arg_extra_parens
7104 : diag::ext_template_arg_extra_parens)
7105 << Arg->getSourceRange();
7106 ExtraParens = true;
7107 }
7108
7109 Arg = Parens->getSubExpr();
7110 }
7111
7112 while (SubstNonTypeTemplateParmExpr *subst =
7113 dyn_cast<SubstNonTypeTemplateParmExpr>(Arg))
7114 Arg = subst->getReplacement()->IgnoreImpCasts();
7115
7116 // A pointer-to-member constant written &Class::member.
7117 if (UnaryOperator *UnOp = dyn_cast<UnaryOperator>(Arg)) {
7118 if (UnOp->getOpcode() == UO_AddrOf) {
7119 DRE = dyn_cast<DeclRefExpr>(UnOp->getSubExpr());
7120 if (DRE && !DRE->getQualifier())
7121 DRE = nullptr;
7122 }
7123 }
7124 // A constant of pointer-to-member type.
7125 else if ((DRE = dyn_cast<DeclRefExpr>(Arg))) {
7126 ValueDecl *VD = DRE->getDecl();
7127 if (VD->getType()->isMemberPointerType()) {
7128 if (isa<NonTypeTemplateParmDecl>(VD)) {
7129 if (Arg->isTypeDependent() || Arg->isValueDependent()) {
7130 SugaredConverted = TemplateArgument(Arg);
7131 CanonicalConverted =
7132 S.Context.getCanonicalTemplateArgument(SugaredConverted);
7133 } else {
7134 SugaredConverted = TemplateArgument(VD, ParamType);
7135 CanonicalConverted =
7136 TemplateArgument(cast<ValueDecl>(VD->getCanonicalDecl()),
7137 S.Context.getCanonicalType(ParamType));
7138 }
7139 return Invalid;
7140 }
7141 }
7142
7143 DRE = nullptr;
7144 }
7145
7146 ValueDecl *Entity = DRE ? DRE->getDecl() : nullptr;
7147
7148 // Check for a null pointer value.
7149 switch (isNullPointerValueTemplateArgument(S, Param, ParamType, ResultArg,
7150 Entity)) {
7151 case NPV_Error:
7152 return true;
7153 case NPV_NullPointer:
7154 S.Diag(ResultArg->getExprLoc(), diag::warn_cxx98_compat_template_arg_null);
7155 SugaredConverted = TemplateArgument(ParamType,
7156 /*isNullPtr*/ true);
7157 CanonicalConverted = TemplateArgument(S.Context.getCanonicalType(ParamType),
7158 /*isNullPtr*/ true);
7159 return false;
7160 case NPV_NotNullPointer:
7161 break;
7162 }
7163
7164 if (S.IsQualificationConversion(ResultArg->getType(),
7165 ParamType.getNonReferenceType(), false,
7166 ObjCLifetimeConversion)) {
7167 ResultArg = S.ImpCastExprToType(ResultArg, ParamType, CK_NoOp,
7168 ResultArg->getValueKind())
7169 .get();
7170 } else if (!S.Context.hasSameUnqualifiedType(
7171 ResultArg->getType(), ParamType.getNonReferenceType())) {
7172 // We can't perform this conversion.
7173 S.Diag(ResultArg->getBeginLoc(), diag::err_template_arg_not_convertible)
7174 << ResultArg->getType() << ParamType << ResultArg->getSourceRange();
7175 S.NoteTemplateParameterLocation(*Param);
7176 return true;
7177 }
7178
7179 if (!DRE)
7180 return S.Diag(Arg->getBeginLoc(),
7181 diag::err_template_arg_not_pointer_to_member_form)
7182 << Arg->getSourceRange();
7183
7184 if (isa<FieldDecl>(DRE->getDecl()) ||
7185 isa<IndirectFieldDecl>(DRE->getDecl()) ||
7186 isa<CXXMethodDecl>(DRE->getDecl())) {
7187 assert((isa<FieldDecl>(DRE->getDecl()) ||
7188 isa<IndirectFieldDecl>(DRE->getDecl()) ||
7189 cast<CXXMethodDecl>(DRE->getDecl())
7190 ->isImplicitObjectMemberFunction()) &&
7191 "Only non-static member pointers can make it here");
7192
7193 // Okay: this is the address of a non-static member, and therefore
7194 // a member pointer constant.
7195 if (Arg->isTypeDependent() || Arg->isValueDependent()) {
7196 SugaredConverted = TemplateArgument(Arg);
7197 CanonicalConverted =
7198 S.Context.getCanonicalTemplateArgument(SugaredConverted);
7199 } else {
7200 ValueDecl *D = DRE->getDecl();
7201 SugaredConverted = TemplateArgument(D, ParamType);
7202 CanonicalConverted =
7203 TemplateArgument(cast<ValueDecl>(D->getCanonicalDecl()),
7204 S.Context.getCanonicalType(ParamType));
7205 }
7206 return Invalid;
7207 }
7208
7209 // We found something else, but we don't know specifically what it is.
7210 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_not_pointer_to_member_form)
7211 << Arg->getSourceRange();
7212 S.Diag(DRE->getDecl()->getLocation(), diag::note_template_arg_refers_here);
7213 return true;
7214 }
7215
7216 /// Check a template argument against its corresponding
7217 /// non-type template parameter.
7218 ///
7219 /// This routine implements the semantics of C++ [temp.arg.nontype].
7220 /// If an error occurred, it returns ExprError(); otherwise, it
7221 /// returns the converted template argument. \p ParamType is the
7222 /// type of the non-type template parameter after it has been instantiated.
CheckTemplateArgument(NonTypeTemplateParmDecl * Param,QualType ParamType,Expr * Arg,TemplateArgument & SugaredConverted,TemplateArgument & CanonicalConverted,CheckTemplateArgumentKind CTAK)7223 ExprResult Sema::CheckTemplateArgument(NonTypeTemplateParmDecl *Param,
7224 QualType ParamType, Expr *Arg,
7225 TemplateArgument &SugaredConverted,
7226 TemplateArgument &CanonicalConverted,
7227 CheckTemplateArgumentKind CTAK) {
7228 SourceLocation StartLoc = Arg->getBeginLoc();
7229
7230 // If the parameter type somehow involves auto, deduce the type now.
7231 DeducedType *DeducedT = ParamType->getContainedDeducedType();
7232 if (getLangOpts().CPlusPlus17 && DeducedT && !DeducedT->isDeduced()) {
7233 // During template argument deduction, we allow 'decltype(auto)' to
7234 // match an arbitrary dependent argument.
7235 // FIXME: The language rules don't say what happens in this case.
7236 // FIXME: We get an opaque dependent type out of decltype(auto) if the
7237 // expression is merely instantiation-dependent; is this enough?
7238 if (CTAK == CTAK_Deduced && Arg->isTypeDependent()) {
7239 auto *AT = dyn_cast<AutoType>(DeducedT);
7240 if (AT && AT->isDecltypeAuto()) {
7241 SugaredConverted = TemplateArgument(Arg);
7242 CanonicalConverted = TemplateArgument(
7243 Context.getCanonicalTemplateArgument(SugaredConverted));
7244 return Arg;
7245 }
7246 }
7247
7248 // When checking a deduced template argument, deduce from its type even if
7249 // the type is dependent, in order to check the types of non-type template
7250 // arguments line up properly in partial ordering.
7251 Expr *DeductionArg = Arg;
7252 if (auto *PE = dyn_cast<PackExpansionExpr>(DeductionArg))
7253 DeductionArg = PE->getPattern();
7254 TypeSourceInfo *TSI =
7255 Context.getTrivialTypeSourceInfo(ParamType, Param->getLocation());
7256 if (isa<DeducedTemplateSpecializationType>(DeducedT)) {
7257 InitializedEntity Entity =
7258 InitializedEntity::InitializeTemplateParameter(ParamType, Param);
7259 InitializationKind Kind = InitializationKind::CreateForInit(
7260 DeductionArg->getBeginLoc(), /*DirectInit*/false, DeductionArg);
7261 Expr *Inits[1] = {DeductionArg};
7262 ParamType =
7263 DeduceTemplateSpecializationFromInitializer(TSI, Entity, Kind, Inits);
7264 if (ParamType.isNull())
7265 return ExprError();
7266 } else {
7267 TemplateDeductionInfo Info(DeductionArg->getExprLoc(),
7268 Param->getDepth() + 1);
7269 ParamType = QualType();
7270 TemplateDeductionResult Result =
7271 DeduceAutoType(TSI->getTypeLoc(), DeductionArg, ParamType, Info,
7272 /*DependentDeduction=*/true,
7273 // We do not check constraints right now because the
7274 // immediately-declared constraint of the auto type is
7275 // also an associated constraint, and will be checked
7276 // along with the other associated constraints after
7277 // checking the template argument list.
7278 /*IgnoreConstraints=*/true);
7279 if (Result == TDK_AlreadyDiagnosed) {
7280 if (ParamType.isNull())
7281 return ExprError();
7282 } else if (Result != TDK_Success) {
7283 Diag(Arg->getExprLoc(),
7284 diag::err_non_type_template_parm_type_deduction_failure)
7285 << Param->getDeclName() << Param->getType() << Arg->getType()
7286 << Arg->getSourceRange();
7287 NoteTemplateParameterLocation(*Param);
7288 return ExprError();
7289 }
7290 }
7291 // CheckNonTypeTemplateParameterType will produce a diagnostic if there's
7292 // an error. The error message normally references the parameter
7293 // declaration, but here we'll pass the argument location because that's
7294 // where the parameter type is deduced.
7295 ParamType = CheckNonTypeTemplateParameterType(ParamType, Arg->getExprLoc());
7296 if (ParamType.isNull()) {
7297 NoteTemplateParameterLocation(*Param);
7298 return ExprError();
7299 }
7300 }
7301
7302 // We should have already dropped all cv-qualifiers by now.
7303 assert(!ParamType.hasQualifiers() &&
7304 "non-type template parameter type cannot be qualified");
7305
7306 // FIXME: When Param is a reference, should we check that Arg is an lvalue?
7307 if (CTAK == CTAK_Deduced &&
7308 (ParamType->isReferenceType()
7309 ? !Context.hasSameType(ParamType.getNonReferenceType(),
7310 Arg->getType())
7311 : !Context.hasSameUnqualifiedType(ParamType, Arg->getType()))) {
7312 // FIXME: If either type is dependent, we skip the check. This isn't
7313 // correct, since during deduction we're supposed to have replaced each
7314 // template parameter with some unique (non-dependent) placeholder.
7315 // FIXME: If the argument type contains 'auto', we carry on and fail the
7316 // type check in order to force specific types to be more specialized than
7317 // 'auto'. It's not clear how partial ordering with 'auto' is supposed to
7318 // work. Similarly for CTAD, when comparing 'A<x>' against 'A'.
7319 if ((ParamType->isDependentType() || Arg->isTypeDependent()) &&
7320 !Arg->getType()->getContainedDeducedType()) {
7321 SugaredConverted = TemplateArgument(Arg);
7322 CanonicalConverted = TemplateArgument(
7323 Context.getCanonicalTemplateArgument(SugaredConverted));
7324 return Arg;
7325 }
7326 // FIXME: This attempts to implement C++ [temp.deduct.type]p17. Per DR1770,
7327 // we should actually be checking the type of the template argument in P,
7328 // not the type of the template argument deduced from A, against the
7329 // template parameter type.
7330 Diag(StartLoc, diag::err_deduced_non_type_template_arg_type_mismatch)
7331 << Arg->getType()
7332 << ParamType.getUnqualifiedType();
7333 NoteTemplateParameterLocation(*Param);
7334 return ExprError();
7335 }
7336
7337 // If either the parameter has a dependent type or the argument is
7338 // type-dependent, there's nothing we can check now.
7339 if (ParamType->isDependentType() || Arg->isTypeDependent()) {
7340 // Force the argument to the type of the parameter to maintain invariants.
7341 auto *PE = dyn_cast<PackExpansionExpr>(Arg);
7342 if (PE)
7343 Arg = PE->getPattern();
7344 ExprResult E = ImpCastExprToType(
7345 Arg, ParamType.getNonLValueExprType(Context), CK_Dependent,
7346 ParamType->isLValueReferenceType() ? VK_LValue
7347 : ParamType->isRValueReferenceType() ? VK_XValue
7348 : VK_PRValue);
7349 if (E.isInvalid())
7350 return ExprError();
7351 if (PE) {
7352 // Recreate a pack expansion if we unwrapped one.
7353 E = new (Context)
7354 PackExpansionExpr(E.get()->getType(), E.get(), PE->getEllipsisLoc(),
7355 PE->getNumExpansions());
7356 }
7357 SugaredConverted = TemplateArgument(E.get());
7358 CanonicalConverted = TemplateArgument(
7359 Context.getCanonicalTemplateArgument(SugaredConverted));
7360 return E;
7361 }
7362
7363 QualType CanonParamType = Context.getCanonicalType(ParamType);
7364 // Avoid making a copy when initializing a template parameter of class type
7365 // from a template parameter object of the same type. This is going beyond
7366 // the standard, but is required for soundness: in
7367 // template<A a> struct X { X *p; X<a> *q; };
7368 // ... we need p and q to have the same type.
7369 //
7370 // Similarly, don't inject a call to a copy constructor when initializing
7371 // from a template parameter of the same type.
7372 Expr *InnerArg = Arg->IgnoreParenImpCasts();
7373 if (ParamType->isRecordType() && isa<DeclRefExpr>(InnerArg) &&
7374 Context.hasSameUnqualifiedType(ParamType, InnerArg->getType())) {
7375 NamedDecl *ND = cast<DeclRefExpr>(InnerArg)->getDecl();
7376 if (auto *TPO = dyn_cast<TemplateParamObjectDecl>(ND)) {
7377
7378 SugaredConverted = TemplateArgument(TPO, ParamType);
7379 CanonicalConverted =
7380 TemplateArgument(TPO->getCanonicalDecl(), CanonParamType);
7381 return Arg;
7382 }
7383 if (isa<NonTypeTemplateParmDecl>(ND)) {
7384 SugaredConverted = TemplateArgument(Arg);
7385 CanonicalConverted =
7386 Context.getCanonicalTemplateArgument(SugaredConverted);
7387 return Arg;
7388 }
7389 }
7390
7391 // The initialization of the parameter from the argument is
7392 // a constant-evaluated context.
7393 EnterExpressionEvaluationContext ConstantEvaluated(
7394 *this, Sema::ExpressionEvaluationContext::ConstantEvaluated);
7395
7396 bool IsConvertedConstantExpression = true;
7397 if (isa<InitListExpr>(Arg) || ParamType->isRecordType()) {
7398 InitializationKind Kind = InitializationKind::CreateForInit(
7399 Arg->getBeginLoc(), /*DirectInit=*/false, Arg);
7400 Expr *Inits[1] = {Arg};
7401 InitializedEntity Entity =
7402 InitializedEntity::InitializeTemplateParameter(ParamType, Param);
7403 InitializationSequence InitSeq(*this, Entity, Kind, Inits);
7404 ExprResult Result = InitSeq.Perform(*this, Entity, Kind, Inits);
7405 if (Result.isInvalid() || !Result.get())
7406 return ExprError();
7407 Result = ActOnConstantExpression(Result.get());
7408 if (Result.isInvalid() || !Result.get())
7409 return ExprError();
7410 Arg = ActOnFinishFullExpr(Result.get(), Arg->getBeginLoc(),
7411 /*DiscardedValue=*/false,
7412 /*IsConstexpr=*/true, /*IsTemplateArgument=*/true)
7413 .get();
7414 IsConvertedConstantExpression = false;
7415 }
7416
7417 if (getLangOpts().CPlusPlus17) {
7418 // C++17 [temp.arg.nontype]p1:
7419 // A template-argument for a non-type template parameter shall be
7420 // a converted constant expression of the type of the template-parameter.
7421 APValue Value;
7422 ExprResult ArgResult;
7423 if (IsConvertedConstantExpression) {
7424 ArgResult = BuildConvertedConstantExpression(Arg, ParamType,
7425 CCEK_TemplateArg, Param);
7426 if (ArgResult.isInvalid())
7427 return ExprError();
7428 } else {
7429 ArgResult = Arg;
7430 }
7431
7432 // For a value-dependent argument, CheckConvertedConstantExpression is
7433 // permitted (and expected) to be unable to determine a value.
7434 if (ArgResult.get()->isValueDependent()) {
7435 SugaredConverted = TemplateArgument(ArgResult.get());
7436 CanonicalConverted =
7437 Context.getCanonicalTemplateArgument(SugaredConverted);
7438 return ArgResult;
7439 }
7440
7441 APValue PreNarrowingValue;
7442 ArgResult = EvaluateConvertedConstantExpression(
7443 ArgResult.get(), ParamType, Value, CCEK_TemplateArg, /*RequireInt=*/
7444 false, PreNarrowingValue);
7445 if (ArgResult.isInvalid())
7446 return ExprError();
7447
7448 if (Value.isLValue()) {
7449 APValue::LValueBase Base = Value.getLValueBase();
7450 auto *VD = const_cast<ValueDecl *>(Base.dyn_cast<const ValueDecl *>());
7451 // For a non-type template-parameter of pointer or reference type,
7452 // the value of the constant expression shall not refer to
7453 assert(ParamType->isPointerType() || ParamType->isReferenceType() ||
7454 ParamType->isNullPtrType());
7455 // -- a temporary object
7456 // -- a string literal
7457 // -- the result of a typeid expression, or
7458 // -- a predefined __func__ variable
7459 if (Base &&
7460 (!VD ||
7461 isa<LifetimeExtendedTemporaryDecl, UnnamedGlobalConstantDecl>(VD))) {
7462 Diag(Arg->getBeginLoc(), diag::err_template_arg_not_decl_ref)
7463 << Arg->getSourceRange();
7464 return ExprError();
7465 }
7466
7467 if (Value.hasLValuePath() && Value.getLValuePath().size() == 1 && VD &&
7468 VD->getType()->isArrayType() &&
7469 Value.getLValuePath()[0].getAsArrayIndex() == 0 &&
7470 !Value.isLValueOnePastTheEnd() && ParamType->isPointerType()) {
7471 SugaredConverted = TemplateArgument(VD, ParamType);
7472 CanonicalConverted = TemplateArgument(
7473 cast<ValueDecl>(VD->getCanonicalDecl()), CanonParamType);
7474 return ArgResult.get();
7475 }
7476
7477 // -- a subobject [until C++20]
7478 if (!getLangOpts().CPlusPlus20) {
7479 if (!Value.hasLValuePath() || Value.getLValuePath().size() ||
7480 Value.isLValueOnePastTheEnd()) {
7481 Diag(StartLoc, diag::err_non_type_template_arg_subobject)
7482 << Value.getAsString(Context, ParamType);
7483 return ExprError();
7484 }
7485 assert((VD || !ParamType->isReferenceType()) &&
7486 "null reference should not be a constant expression");
7487 assert((!VD || !ParamType->isNullPtrType()) &&
7488 "non-null value of type nullptr_t?");
7489 }
7490 }
7491
7492 if (Value.isAddrLabelDiff())
7493 return Diag(StartLoc, diag::err_non_type_template_arg_addr_label_diff);
7494
7495 SugaredConverted = TemplateArgument(Context, ParamType, Value);
7496 CanonicalConverted = TemplateArgument(Context, CanonParamType, Value);
7497 return ArgResult.get();
7498 }
7499
7500 // C++ [temp.arg.nontype]p5:
7501 // The following conversions are performed on each expression used
7502 // as a non-type template-argument. If a non-type
7503 // template-argument cannot be converted to the type of the
7504 // corresponding template-parameter then the program is
7505 // ill-formed.
7506 if (ParamType->isIntegralOrEnumerationType()) {
7507 // C++11:
7508 // -- for a non-type template-parameter of integral or
7509 // enumeration type, conversions permitted in a converted
7510 // constant expression are applied.
7511 //
7512 // C++98:
7513 // -- for a non-type template-parameter of integral or
7514 // enumeration type, integral promotions (4.5) and integral
7515 // conversions (4.7) are applied.
7516
7517 if (getLangOpts().CPlusPlus11) {
7518 // C++ [temp.arg.nontype]p1:
7519 // A template-argument for a non-type, non-template template-parameter
7520 // shall be one of:
7521 //
7522 // -- for a non-type template-parameter of integral or enumeration
7523 // type, a converted constant expression of the type of the
7524 // template-parameter; or
7525 llvm::APSInt Value;
7526 ExprResult ArgResult =
7527 CheckConvertedConstantExpression(Arg, ParamType, Value,
7528 CCEK_TemplateArg);
7529 if (ArgResult.isInvalid())
7530 return ExprError();
7531
7532 // We can't check arbitrary value-dependent arguments.
7533 if (ArgResult.get()->isValueDependent()) {
7534 SugaredConverted = TemplateArgument(ArgResult.get());
7535 CanonicalConverted =
7536 Context.getCanonicalTemplateArgument(SugaredConverted);
7537 return ArgResult;
7538 }
7539
7540 // Widen the argument value to sizeof(parameter type). This is almost
7541 // always a no-op, except when the parameter type is bool. In
7542 // that case, this may extend the argument from 1 bit to 8 bits.
7543 QualType IntegerType = ParamType;
7544 if (const EnumType *Enum = IntegerType->getAs<EnumType>())
7545 IntegerType = Enum->getDecl()->getIntegerType();
7546 Value = Value.extOrTrunc(IntegerType->isBitIntType()
7547 ? Context.getIntWidth(IntegerType)
7548 : Context.getTypeSize(IntegerType));
7549
7550 SugaredConverted = TemplateArgument(Context, Value, ParamType);
7551 CanonicalConverted =
7552 TemplateArgument(Context, Value, Context.getCanonicalType(ParamType));
7553 return ArgResult;
7554 }
7555
7556 ExprResult ArgResult = DefaultLvalueConversion(Arg);
7557 if (ArgResult.isInvalid())
7558 return ExprError();
7559 Arg = ArgResult.get();
7560
7561 QualType ArgType = Arg->getType();
7562
7563 // C++ [temp.arg.nontype]p1:
7564 // A template-argument for a non-type, non-template
7565 // template-parameter shall be one of:
7566 //
7567 // -- an integral constant-expression of integral or enumeration
7568 // type; or
7569 // -- the name of a non-type template-parameter; or
7570 llvm::APSInt Value;
7571 if (!ArgType->isIntegralOrEnumerationType()) {
7572 Diag(Arg->getBeginLoc(), diag::err_template_arg_not_integral_or_enumeral)
7573 << ArgType << Arg->getSourceRange();
7574 NoteTemplateParameterLocation(*Param);
7575 return ExprError();
7576 } else if (!Arg->isValueDependent()) {
7577 class TmplArgICEDiagnoser : public VerifyICEDiagnoser {
7578 QualType T;
7579
7580 public:
7581 TmplArgICEDiagnoser(QualType T) : T(T) { }
7582
7583 SemaDiagnosticBuilder diagnoseNotICE(Sema &S,
7584 SourceLocation Loc) override {
7585 return S.Diag(Loc, diag::err_template_arg_not_ice) << T;
7586 }
7587 } Diagnoser(ArgType);
7588
7589 Arg = VerifyIntegerConstantExpression(Arg, &Value, Diagnoser).get();
7590 if (!Arg)
7591 return ExprError();
7592 }
7593
7594 // From here on out, all we care about is the unqualified form
7595 // of the argument type.
7596 ArgType = ArgType.getUnqualifiedType();
7597
7598 // Try to convert the argument to the parameter's type.
7599 if (Context.hasSameType(ParamType, ArgType)) {
7600 // Okay: no conversion necessary
7601 } else if (ParamType->isBooleanType()) {
7602 // This is an integral-to-boolean conversion.
7603 Arg = ImpCastExprToType(Arg, ParamType, CK_IntegralToBoolean).get();
7604 } else if (IsIntegralPromotion(Arg, ArgType, ParamType) ||
7605 !ParamType->isEnumeralType()) {
7606 // This is an integral promotion or conversion.
7607 Arg = ImpCastExprToType(Arg, ParamType, CK_IntegralCast).get();
7608 } else {
7609 // We can't perform this conversion.
7610 Diag(Arg->getBeginLoc(), diag::err_template_arg_not_convertible)
7611 << Arg->getType() << ParamType << Arg->getSourceRange();
7612 NoteTemplateParameterLocation(*Param);
7613 return ExprError();
7614 }
7615
7616 // Add the value of this argument to the list of converted
7617 // arguments. We use the bitwidth and signedness of the template
7618 // parameter.
7619 if (Arg->isValueDependent()) {
7620 // The argument is value-dependent. Create a new
7621 // TemplateArgument with the converted expression.
7622 SugaredConverted = TemplateArgument(Arg);
7623 CanonicalConverted =
7624 Context.getCanonicalTemplateArgument(SugaredConverted);
7625 return Arg;
7626 }
7627
7628 QualType IntegerType = ParamType;
7629 if (const EnumType *Enum = IntegerType->getAs<EnumType>()) {
7630 IntegerType = Enum->getDecl()->getIntegerType();
7631 }
7632
7633 if (ParamType->isBooleanType()) {
7634 // Value must be zero or one.
7635 Value = Value != 0;
7636 unsigned AllowedBits = Context.getTypeSize(IntegerType);
7637 if (Value.getBitWidth() != AllowedBits)
7638 Value = Value.extOrTrunc(AllowedBits);
7639 Value.setIsSigned(IntegerType->isSignedIntegerOrEnumerationType());
7640 } else {
7641 llvm::APSInt OldValue = Value;
7642
7643 // Coerce the template argument's value to the value it will have
7644 // based on the template parameter's type.
7645 unsigned AllowedBits = IntegerType->isBitIntType()
7646 ? Context.getIntWidth(IntegerType)
7647 : Context.getTypeSize(IntegerType);
7648 if (Value.getBitWidth() != AllowedBits)
7649 Value = Value.extOrTrunc(AllowedBits);
7650 Value.setIsSigned(IntegerType->isSignedIntegerOrEnumerationType());
7651
7652 // Complain if an unsigned parameter received a negative value.
7653 if (IntegerType->isUnsignedIntegerOrEnumerationType() &&
7654 (OldValue.isSigned() && OldValue.isNegative())) {
7655 Diag(Arg->getBeginLoc(), diag::warn_template_arg_negative)
7656 << toString(OldValue, 10) << toString(Value, 10) << Param->getType()
7657 << Arg->getSourceRange();
7658 NoteTemplateParameterLocation(*Param);
7659 }
7660
7661 // Complain if we overflowed the template parameter's type.
7662 unsigned RequiredBits;
7663 if (IntegerType->isUnsignedIntegerOrEnumerationType())
7664 RequiredBits = OldValue.getActiveBits();
7665 else if (OldValue.isUnsigned())
7666 RequiredBits = OldValue.getActiveBits() + 1;
7667 else
7668 RequiredBits = OldValue.getSignificantBits();
7669 if (RequiredBits > AllowedBits) {
7670 Diag(Arg->getBeginLoc(), diag::warn_template_arg_too_large)
7671 << toString(OldValue, 10) << toString(Value, 10) << Param->getType()
7672 << Arg->getSourceRange();
7673 NoteTemplateParameterLocation(*Param);
7674 }
7675 }
7676
7677 QualType T = ParamType->isEnumeralType() ? ParamType : IntegerType;
7678 SugaredConverted = TemplateArgument(Context, Value, T);
7679 CanonicalConverted =
7680 TemplateArgument(Context, Value, Context.getCanonicalType(T));
7681 return Arg;
7682 }
7683
7684 QualType ArgType = Arg->getType();
7685 DeclAccessPair FoundResult; // temporary for ResolveOverloadedFunction
7686
7687 // Handle pointer-to-function, reference-to-function, and
7688 // pointer-to-member-function all in (roughly) the same way.
7689 if (// -- For a non-type template-parameter of type pointer to
7690 // function, only the function-to-pointer conversion (4.3) is
7691 // applied. If the template-argument represents a set of
7692 // overloaded functions (or a pointer to such), the matching
7693 // function is selected from the set (13.4).
7694 (ParamType->isPointerType() &&
7695 ParamType->castAs<PointerType>()->getPointeeType()->isFunctionType()) ||
7696 // -- For a non-type template-parameter of type reference to
7697 // function, no conversions apply. If the template-argument
7698 // represents a set of overloaded functions, the matching
7699 // function is selected from the set (13.4).
7700 (ParamType->isReferenceType() &&
7701 ParamType->castAs<ReferenceType>()->getPointeeType()->isFunctionType()) ||
7702 // -- For a non-type template-parameter of type pointer to
7703 // member function, no conversions apply. If the
7704 // template-argument represents a set of overloaded member
7705 // functions, the matching member function is selected from
7706 // the set (13.4).
7707 (ParamType->isMemberPointerType() &&
7708 ParamType->castAs<MemberPointerType>()->getPointeeType()
7709 ->isFunctionType())) {
7710
7711 if (Arg->getType() == Context.OverloadTy) {
7712 if (FunctionDecl *Fn = ResolveAddressOfOverloadedFunction(Arg, ParamType,
7713 true,
7714 FoundResult)) {
7715 if (DiagnoseUseOfDecl(Fn, Arg->getBeginLoc()))
7716 return ExprError();
7717
7718 ExprResult Res = FixOverloadedFunctionReference(Arg, FoundResult, Fn);
7719 if (Res.isInvalid())
7720 return ExprError();
7721 Arg = Res.get();
7722 ArgType = Arg->getType();
7723 } else
7724 return ExprError();
7725 }
7726
7727 if (!ParamType->isMemberPointerType()) {
7728 if (CheckTemplateArgumentAddressOfObjectOrFunction(
7729 *this, Param, ParamType, Arg, SugaredConverted,
7730 CanonicalConverted))
7731 return ExprError();
7732 return Arg;
7733 }
7734
7735 if (CheckTemplateArgumentPointerToMember(
7736 *this, Param, ParamType, Arg, SugaredConverted, CanonicalConverted))
7737 return ExprError();
7738 return Arg;
7739 }
7740
7741 if (ParamType->isPointerType()) {
7742 // -- for a non-type template-parameter of type pointer to
7743 // object, qualification conversions (4.4) and the
7744 // array-to-pointer conversion (4.2) are applied.
7745 // C++0x also allows a value of std::nullptr_t.
7746 assert(ParamType->getPointeeType()->isIncompleteOrObjectType() &&
7747 "Only object pointers allowed here");
7748
7749 if (CheckTemplateArgumentAddressOfObjectOrFunction(
7750 *this, Param, ParamType, Arg, SugaredConverted, CanonicalConverted))
7751 return ExprError();
7752 return Arg;
7753 }
7754
7755 if (const ReferenceType *ParamRefType = ParamType->getAs<ReferenceType>()) {
7756 // -- For a non-type template-parameter of type reference to
7757 // object, no conversions apply. The type referred to by the
7758 // reference may be more cv-qualified than the (otherwise
7759 // identical) type of the template-argument. The
7760 // template-parameter is bound directly to the
7761 // template-argument, which must be an lvalue.
7762 assert(ParamRefType->getPointeeType()->isIncompleteOrObjectType() &&
7763 "Only object references allowed here");
7764
7765 if (Arg->getType() == Context.OverloadTy) {
7766 if (FunctionDecl *Fn = ResolveAddressOfOverloadedFunction(Arg,
7767 ParamRefType->getPointeeType(),
7768 true,
7769 FoundResult)) {
7770 if (DiagnoseUseOfDecl(Fn, Arg->getBeginLoc()))
7771 return ExprError();
7772 ExprResult Res = FixOverloadedFunctionReference(Arg, FoundResult, Fn);
7773 if (Res.isInvalid())
7774 return ExprError();
7775 Arg = Res.get();
7776 ArgType = Arg->getType();
7777 } else
7778 return ExprError();
7779 }
7780
7781 if (CheckTemplateArgumentAddressOfObjectOrFunction(
7782 *this, Param, ParamType, Arg, SugaredConverted, CanonicalConverted))
7783 return ExprError();
7784 return Arg;
7785 }
7786
7787 // Deal with parameters of type std::nullptr_t.
7788 if (ParamType->isNullPtrType()) {
7789 if (Arg->isTypeDependent() || Arg->isValueDependent()) {
7790 SugaredConverted = TemplateArgument(Arg);
7791 CanonicalConverted =
7792 Context.getCanonicalTemplateArgument(SugaredConverted);
7793 return Arg;
7794 }
7795
7796 switch (isNullPointerValueTemplateArgument(*this, Param, ParamType, Arg)) {
7797 case NPV_NotNullPointer:
7798 Diag(Arg->getExprLoc(), diag::err_template_arg_not_convertible)
7799 << Arg->getType() << ParamType;
7800 NoteTemplateParameterLocation(*Param);
7801 return ExprError();
7802
7803 case NPV_Error:
7804 return ExprError();
7805
7806 case NPV_NullPointer:
7807 Diag(Arg->getExprLoc(), diag::warn_cxx98_compat_template_arg_null);
7808 SugaredConverted = TemplateArgument(ParamType,
7809 /*isNullPtr=*/true);
7810 CanonicalConverted = TemplateArgument(Context.getCanonicalType(ParamType),
7811 /*isNullPtr=*/true);
7812 return Arg;
7813 }
7814 }
7815
7816 // -- For a non-type template-parameter of type pointer to data
7817 // member, qualification conversions (4.4) are applied.
7818 assert(ParamType->isMemberPointerType() && "Only pointers to members remain");
7819
7820 if (CheckTemplateArgumentPointerToMember(
7821 *this, Param, ParamType, Arg, SugaredConverted, CanonicalConverted))
7822 return ExprError();
7823 return Arg;
7824 }
7825
7826 static void DiagnoseTemplateParameterListArityMismatch(
7827 Sema &S, TemplateParameterList *New, TemplateParameterList *Old,
7828 Sema::TemplateParameterListEqualKind Kind, SourceLocation TemplateArgLoc);
7829
7830 /// Check a template argument against its corresponding
7831 /// template template parameter.
7832 ///
7833 /// This routine implements the semantics of C++ [temp.arg.template].
7834 /// It returns true if an error occurred, and false otherwise.
CheckTemplateTemplateArgument(TemplateTemplateParmDecl * Param,TemplateParameterList * Params,TemplateArgumentLoc & Arg)7835 bool Sema::CheckTemplateTemplateArgument(TemplateTemplateParmDecl *Param,
7836 TemplateParameterList *Params,
7837 TemplateArgumentLoc &Arg) {
7838 TemplateName Name = Arg.getArgument().getAsTemplateOrTemplatePattern();
7839 TemplateDecl *Template = Name.getAsTemplateDecl();
7840 if (!Template) {
7841 // Any dependent template name is fine.
7842 assert(Name.isDependent() && "Non-dependent template isn't a declaration?");
7843 return false;
7844 }
7845
7846 if (Template->isInvalidDecl())
7847 return true;
7848
7849 // C++0x [temp.arg.template]p1:
7850 // A template-argument for a template template-parameter shall be
7851 // the name of a class template or an alias template, expressed as an
7852 // id-expression. When the template-argument names a class template, only
7853 // primary class templates are considered when matching the
7854 // template template argument with the corresponding parameter;
7855 // partial specializations are not considered even if their
7856 // parameter lists match that of the template template parameter.
7857 //
7858 // Note that we also allow template template parameters here, which
7859 // will happen when we are dealing with, e.g., class template
7860 // partial specializations.
7861 if (!isa<ClassTemplateDecl>(Template) &&
7862 !isa<TemplateTemplateParmDecl>(Template) &&
7863 !isa<TypeAliasTemplateDecl>(Template) &&
7864 !isa<BuiltinTemplateDecl>(Template)) {
7865 assert(isa<FunctionTemplateDecl>(Template) &&
7866 "Only function templates are possible here");
7867 Diag(Arg.getLocation(), diag::err_template_arg_not_valid_template);
7868 Diag(Template->getLocation(), diag::note_template_arg_refers_here_func)
7869 << Template;
7870 }
7871
7872 // C++1z [temp.arg.template]p3: (DR 150)
7873 // A template-argument matches a template template-parameter P when P
7874 // is at least as specialized as the template-argument A.
7875 // FIXME: We should enable RelaxedTemplateTemplateArgs by default as it is a
7876 // defect report resolution from C++17 and shouldn't be introduced by
7877 // concepts.
7878 if (getLangOpts().RelaxedTemplateTemplateArgs) {
7879 // Quick check for the common case:
7880 // If P contains a parameter pack, then A [...] matches P if each of A's
7881 // template parameters matches the corresponding template parameter in
7882 // the template-parameter-list of P.
7883 if (TemplateParameterListsAreEqual(
7884 Template->getTemplateParameters(), Params, false,
7885 TPL_TemplateTemplateArgumentMatch, Arg.getLocation()) &&
7886 // If the argument has no associated constraints, then the parameter is
7887 // definitely at least as specialized as the argument.
7888 // Otherwise - we need a more thorough check.
7889 !Template->hasAssociatedConstraints())
7890 return false;
7891
7892 if (isTemplateTemplateParameterAtLeastAsSpecializedAs(Params, Template,
7893 Arg.getLocation())) {
7894 // P2113
7895 // C++20[temp.func.order]p2
7896 // [...] If both deductions succeed, the partial ordering selects the
7897 // more constrained template (if one exists) as determined below.
7898 SmallVector<const Expr *, 3> ParamsAC, TemplateAC;
7899 Params->getAssociatedConstraints(ParamsAC);
7900 // C++2a[temp.arg.template]p3
7901 // [...] In this comparison, if P is unconstrained, the constraints on A
7902 // are not considered.
7903 if (ParamsAC.empty())
7904 return false;
7905
7906 Template->getAssociatedConstraints(TemplateAC);
7907
7908 bool IsParamAtLeastAsConstrained;
7909 if (IsAtLeastAsConstrained(Param, ParamsAC, Template, TemplateAC,
7910 IsParamAtLeastAsConstrained))
7911 return true;
7912 if (!IsParamAtLeastAsConstrained) {
7913 Diag(Arg.getLocation(),
7914 diag::err_template_template_parameter_not_at_least_as_constrained)
7915 << Template << Param << Arg.getSourceRange();
7916 Diag(Param->getLocation(), diag::note_entity_declared_at) << Param;
7917 Diag(Template->getLocation(), diag::note_entity_declared_at)
7918 << Template;
7919 MaybeEmitAmbiguousAtomicConstraintsDiagnostic(Param, ParamsAC, Template,
7920 TemplateAC);
7921 return true;
7922 }
7923 return false;
7924 }
7925 // FIXME: Produce better diagnostics for deduction failures.
7926 }
7927
7928 return !TemplateParameterListsAreEqual(Template->getTemplateParameters(),
7929 Params,
7930 true,
7931 TPL_TemplateTemplateArgumentMatch,
7932 Arg.getLocation());
7933 }
7934
noteLocation(Sema & S,const NamedDecl & Decl,unsigned HereDiagID,unsigned ExternalDiagID)7935 static Sema::SemaDiagnosticBuilder noteLocation(Sema &S, const NamedDecl &Decl,
7936 unsigned HereDiagID,
7937 unsigned ExternalDiagID) {
7938 if (Decl.getLocation().isValid())
7939 return S.Diag(Decl.getLocation(), HereDiagID);
7940
7941 SmallString<128> Str;
7942 llvm::raw_svector_ostream Out(Str);
7943 PrintingPolicy PP = S.getPrintingPolicy();
7944 PP.TerseOutput = 1;
7945 Decl.print(Out, PP);
7946 return S.Diag(Decl.getLocation(), ExternalDiagID) << Out.str();
7947 }
7948
NoteTemplateLocation(const NamedDecl & Decl,std::optional<SourceRange> ParamRange)7949 void Sema::NoteTemplateLocation(const NamedDecl &Decl,
7950 std::optional<SourceRange> ParamRange) {
7951 SemaDiagnosticBuilder DB =
7952 noteLocation(*this, Decl, diag::note_template_decl_here,
7953 diag::note_template_decl_external);
7954 if (ParamRange && ParamRange->isValid()) {
7955 assert(Decl.getLocation().isValid() &&
7956 "Parameter range has location when Decl does not");
7957 DB << *ParamRange;
7958 }
7959 }
7960
NoteTemplateParameterLocation(const NamedDecl & Decl)7961 void Sema::NoteTemplateParameterLocation(const NamedDecl &Decl) {
7962 noteLocation(*this, Decl, diag::note_template_param_here,
7963 diag::note_template_param_external);
7964 }
7965
7966 /// Given a non-type template argument that refers to a
7967 /// declaration and the type of its corresponding non-type template
7968 /// parameter, produce an expression that properly refers to that
7969 /// declaration.
7970 ExprResult
BuildExpressionFromDeclTemplateArgument(const TemplateArgument & Arg,QualType ParamType,SourceLocation Loc)7971 Sema::BuildExpressionFromDeclTemplateArgument(const TemplateArgument &Arg,
7972 QualType ParamType,
7973 SourceLocation Loc) {
7974 // C++ [temp.param]p8:
7975 //
7976 // A non-type template-parameter of type "array of T" or
7977 // "function returning T" is adjusted to be of type "pointer to
7978 // T" or "pointer to function returning T", respectively.
7979 if (ParamType->isArrayType())
7980 ParamType = Context.getArrayDecayedType(ParamType);
7981 else if (ParamType->isFunctionType())
7982 ParamType = Context.getPointerType(ParamType);
7983
7984 // For a NULL non-type template argument, return nullptr casted to the
7985 // parameter's type.
7986 if (Arg.getKind() == TemplateArgument::NullPtr) {
7987 return ImpCastExprToType(
7988 new (Context) CXXNullPtrLiteralExpr(Context.NullPtrTy, Loc),
7989 ParamType,
7990 ParamType->getAs<MemberPointerType>()
7991 ? CK_NullToMemberPointer
7992 : CK_NullToPointer);
7993 }
7994 assert(Arg.getKind() == TemplateArgument::Declaration &&
7995 "Only declaration template arguments permitted here");
7996
7997 ValueDecl *VD = Arg.getAsDecl();
7998
7999 CXXScopeSpec SS;
8000 if (ParamType->isMemberPointerType()) {
8001 // If this is a pointer to member, we need to use a qualified name to
8002 // form a suitable pointer-to-member constant.
8003 assert(VD->getDeclContext()->isRecord() &&
8004 (isa<CXXMethodDecl>(VD) || isa<FieldDecl>(VD) ||
8005 isa<IndirectFieldDecl>(VD)));
8006 QualType ClassType
8007 = Context.getTypeDeclType(cast<RecordDecl>(VD->getDeclContext()));
8008 NestedNameSpecifier *Qualifier
8009 = NestedNameSpecifier::Create(Context, nullptr, false,
8010 ClassType.getTypePtr());
8011 SS.MakeTrivial(Context, Qualifier, Loc);
8012 }
8013
8014 ExprResult RefExpr = BuildDeclarationNameExpr(
8015 SS, DeclarationNameInfo(VD->getDeclName(), Loc), VD);
8016 if (RefExpr.isInvalid())
8017 return ExprError();
8018
8019 // For a pointer, the argument declaration is the pointee. Take its address.
8020 QualType ElemT(RefExpr.get()->getType()->getArrayElementTypeNoTypeQual(), 0);
8021 if (ParamType->isPointerType() && !ElemT.isNull() &&
8022 Context.hasSimilarType(ElemT, ParamType->getPointeeType())) {
8023 // Decay an array argument if we want a pointer to its first element.
8024 RefExpr = DefaultFunctionArrayConversion(RefExpr.get());
8025 if (RefExpr.isInvalid())
8026 return ExprError();
8027 } else if (ParamType->isPointerType() || ParamType->isMemberPointerType()) {
8028 // For any other pointer, take the address (or form a pointer-to-member).
8029 RefExpr = CreateBuiltinUnaryOp(Loc, UO_AddrOf, RefExpr.get());
8030 if (RefExpr.isInvalid())
8031 return ExprError();
8032 } else if (ParamType->isRecordType()) {
8033 assert(isa<TemplateParamObjectDecl>(VD) &&
8034 "arg for class template param not a template parameter object");
8035 // No conversions apply in this case.
8036 return RefExpr;
8037 } else {
8038 assert(ParamType->isReferenceType() &&
8039 "unexpected type for decl template argument");
8040 }
8041
8042 // At this point we should have the right value category.
8043 assert(ParamType->isReferenceType() == RefExpr.get()->isLValue() &&
8044 "value kind mismatch for non-type template argument");
8045
8046 // The type of the template parameter can differ from the type of the
8047 // argument in various ways; convert it now if necessary.
8048 QualType DestExprType = ParamType.getNonLValueExprType(Context);
8049 if (!Context.hasSameType(RefExpr.get()->getType(), DestExprType)) {
8050 CastKind CK;
8051 QualType Ignored;
8052 if (Context.hasSimilarType(RefExpr.get()->getType(), DestExprType) ||
8053 IsFunctionConversion(RefExpr.get()->getType(), DestExprType, Ignored)) {
8054 CK = CK_NoOp;
8055 } else if (ParamType->isVoidPointerType() &&
8056 RefExpr.get()->getType()->isPointerType()) {
8057 CK = CK_BitCast;
8058 } else {
8059 // FIXME: Pointers to members can need conversion derived-to-base or
8060 // base-to-derived conversions. We currently don't retain enough
8061 // information to convert properly (we need to track a cast path or
8062 // subobject number in the template argument).
8063 llvm_unreachable(
8064 "unexpected conversion required for non-type template argument");
8065 }
8066 RefExpr = ImpCastExprToType(RefExpr.get(), DestExprType, CK,
8067 RefExpr.get()->getValueKind());
8068 }
8069
8070 return RefExpr;
8071 }
8072
8073 /// Construct a new expression that refers to the given
8074 /// integral template argument with the given source-location
8075 /// information.
8076 ///
8077 /// This routine takes care of the mapping from an integral template
8078 /// argument (which may have any integral type) to the appropriate
8079 /// literal value.
BuildExpressionFromIntegralTemplateArgumentValue(Sema & S,QualType OrigT,const llvm::APSInt & Int,SourceLocation Loc)8080 static Expr *BuildExpressionFromIntegralTemplateArgumentValue(
8081 Sema &S, QualType OrigT, const llvm::APSInt &Int, SourceLocation Loc) {
8082 assert(OrigT->isIntegralOrEnumerationType());
8083
8084 // If this is an enum type that we're instantiating, we need to use an integer
8085 // type the same size as the enumerator. We don't want to build an
8086 // IntegerLiteral with enum type. The integer type of an enum type can be of
8087 // any integral type with C++11 enum classes, make sure we create the right
8088 // type of literal for it.
8089 QualType T = OrigT;
8090 if (const EnumType *ET = OrigT->getAs<EnumType>())
8091 T = ET->getDecl()->getIntegerType();
8092
8093 Expr *E;
8094 if (T->isAnyCharacterType()) {
8095 CharacterLiteralKind Kind;
8096 if (T->isWideCharType())
8097 Kind = CharacterLiteralKind::Wide;
8098 else if (T->isChar8Type() && S.getLangOpts().Char8)
8099 Kind = CharacterLiteralKind::UTF8;
8100 else if (T->isChar16Type())
8101 Kind = CharacterLiteralKind::UTF16;
8102 else if (T->isChar32Type())
8103 Kind = CharacterLiteralKind::UTF32;
8104 else
8105 Kind = CharacterLiteralKind::Ascii;
8106
8107 E = new (S.Context) CharacterLiteral(Int.getZExtValue(), Kind, T, Loc);
8108 } else if (T->isBooleanType()) {
8109 E = CXXBoolLiteralExpr::Create(S.Context, Int.getBoolValue(), T, Loc);
8110 } else {
8111 E = IntegerLiteral::Create(S.Context, Int, T, Loc);
8112 }
8113
8114 if (OrigT->isEnumeralType()) {
8115 // FIXME: This is a hack. We need a better way to handle substituted
8116 // non-type template parameters.
8117 E = CStyleCastExpr::Create(S.Context, OrigT, VK_PRValue, CK_IntegralCast, E,
8118 nullptr, S.CurFPFeatureOverrides(),
8119 S.Context.getTrivialTypeSourceInfo(OrigT, Loc),
8120 Loc, Loc);
8121 }
8122
8123 return E;
8124 }
8125
BuildExpressionFromNonTypeTemplateArgumentValue(Sema & S,QualType T,const APValue & Val,SourceLocation Loc)8126 static Expr *BuildExpressionFromNonTypeTemplateArgumentValue(
8127 Sema &S, QualType T, const APValue &Val, SourceLocation Loc) {
8128 auto MakeInitList = [&](ArrayRef<Expr *> Elts) -> Expr * {
8129 auto *ILE = new (S.Context) InitListExpr(S.Context, Loc, Elts, Loc);
8130 ILE->setType(T);
8131 return ILE;
8132 };
8133
8134 switch (Val.getKind()) {
8135 case APValue::AddrLabelDiff:
8136 // This cannot occur in a template argument at all.
8137 case APValue::Array:
8138 case APValue::Struct:
8139 case APValue::Union:
8140 // These can only occur within a template parameter object, which is
8141 // represented as a TemplateArgument::Declaration.
8142 llvm_unreachable("unexpected template argument value");
8143
8144 case APValue::Int:
8145 return BuildExpressionFromIntegralTemplateArgumentValue(S, T, Val.getInt(),
8146 Loc);
8147
8148 case APValue::Float:
8149 return FloatingLiteral::Create(S.Context, Val.getFloat(), /*IsExact=*/true,
8150 T, Loc);
8151
8152 case APValue::FixedPoint:
8153 return FixedPointLiteral::CreateFromRawInt(
8154 S.Context, Val.getFixedPoint().getValue(), T, Loc,
8155 Val.getFixedPoint().getScale());
8156
8157 case APValue::ComplexInt: {
8158 QualType ElemT = T->castAs<ComplexType>()->getElementType();
8159 return MakeInitList({BuildExpressionFromIntegralTemplateArgumentValue(
8160 S, ElemT, Val.getComplexIntReal(), Loc),
8161 BuildExpressionFromIntegralTemplateArgumentValue(
8162 S, ElemT, Val.getComplexIntImag(), Loc)});
8163 }
8164
8165 case APValue::ComplexFloat: {
8166 QualType ElemT = T->castAs<ComplexType>()->getElementType();
8167 return MakeInitList(
8168 {FloatingLiteral::Create(S.Context, Val.getComplexFloatReal(), true,
8169 ElemT, Loc),
8170 FloatingLiteral::Create(S.Context, Val.getComplexFloatImag(), true,
8171 ElemT, Loc)});
8172 }
8173
8174 case APValue::Vector: {
8175 QualType ElemT = T->castAs<VectorType>()->getElementType();
8176 llvm::SmallVector<Expr *, 8> Elts;
8177 for (unsigned I = 0, N = Val.getVectorLength(); I != N; ++I)
8178 Elts.push_back(BuildExpressionFromNonTypeTemplateArgumentValue(
8179 S, ElemT, Val.getVectorElt(I), Loc));
8180 return MakeInitList(Elts);
8181 }
8182
8183 case APValue::None:
8184 case APValue::Indeterminate:
8185 llvm_unreachable("Unexpected APValue kind.");
8186 case APValue::LValue:
8187 case APValue::MemberPointer:
8188 // There isn't necessarily a valid equivalent source-level syntax for
8189 // these; in particular, a naive lowering might violate access control.
8190 // So for now we lower to a ConstantExpr holding the value, wrapped around
8191 // an OpaqueValueExpr.
8192 // FIXME: We should have a better representation for this.
8193 ExprValueKind VK = VK_PRValue;
8194 if (T->isReferenceType()) {
8195 T = T->getPointeeType();
8196 VK = VK_LValue;
8197 }
8198 auto *OVE = new (S.Context) OpaqueValueExpr(Loc, T, VK);
8199 return ConstantExpr::Create(S.Context, OVE, Val);
8200 }
8201 llvm_unreachable("Unhandled APValue::ValueKind enum");
8202 }
8203
8204 ExprResult
BuildExpressionFromNonTypeTemplateArgument(const TemplateArgument & Arg,SourceLocation Loc)8205 Sema::BuildExpressionFromNonTypeTemplateArgument(const TemplateArgument &Arg,
8206 SourceLocation Loc) {
8207 switch (Arg.getKind()) {
8208 case TemplateArgument::Null:
8209 case TemplateArgument::Type:
8210 case TemplateArgument::Template:
8211 case TemplateArgument::TemplateExpansion:
8212 case TemplateArgument::Pack:
8213 llvm_unreachable("not a non-type template argument");
8214
8215 case TemplateArgument::Expression:
8216 return Arg.getAsExpr();
8217
8218 case TemplateArgument::NullPtr:
8219 case TemplateArgument::Declaration:
8220 return BuildExpressionFromDeclTemplateArgument(
8221 Arg, Arg.getNonTypeTemplateArgumentType(), Loc);
8222
8223 case TemplateArgument::Integral:
8224 return BuildExpressionFromIntegralTemplateArgumentValue(
8225 *this, Arg.getIntegralType(), Arg.getAsIntegral(), Loc);
8226
8227 case TemplateArgument::StructuralValue:
8228 return BuildExpressionFromNonTypeTemplateArgumentValue(
8229 *this, Arg.getStructuralValueType(), Arg.getAsStructuralValue(), Loc);
8230 }
8231 llvm_unreachable("Unhandled TemplateArgument::ArgKind enum");
8232 }
8233
8234 /// Match two template parameters within template parameter lists.
MatchTemplateParameterKind(Sema & S,NamedDecl * New,const Sema::TemplateCompareNewDeclInfo & NewInstFrom,NamedDecl * Old,const NamedDecl * OldInstFrom,bool Complain,Sema::TemplateParameterListEqualKind Kind,SourceLocation TemplateArgLoc)8235 static bool MatchTemplateParameterKind(
8236 Sema &S, NamedDecl *New,
8237 const Sema::TemplateCompareNewDeclInfo &NewInstFrom, NamedDecl *Old,
8238 const NamedDecl *OldInstFrom, bool Complain,
8239 Sema::TemplateParameterListEqualKind Kind, SourceLocation TemplateArgLoc) {
8240 // Check the actual kind (type, non-type, template).
8241 if (Old->getKind() != New->getKind()) {
8242 if (Complain) {
8243 unsigned NextDiag = diag::err_template_param_different_kind;
8244 if (TemplateArgLoc.isValid()) {
8245 S.Diag(TemplateArgLoc, diag::err_template_arg_template_params_mismatch);
8246 NextDiag = diag::note_template_param_different_kind;
8247 }
8248 S.Diag(New->getLocation(), NextDiag)
8249 << (Kind != Sema::TPL_TemplateMatch);
8250 S.Diag(Old->getLocation(), diag::note_template_prev_declaration)
8251 << (Kind != Sema::TPL_TemplateMatch);
8252 }
8253
8254 return false;
8255 }
8256
8257 // Check that both are parameter packs or neither are parameter packs.
8258 // However, if we are matching a template template argument to a
8259 // template template parameter, the template template parameter can have
8260 // a parameter pack where the template template argument does not.
8261 if (Old->isTemplateParameterPack() != New->isTemplateParameterPack() &&
8262 !(Kind == Sema::TPL_TemplateTemplateArgumentMatch &&
8263 Old->isTemplateParameterPack())) {
8264 if (Complain) {
8265 unsigned NextDiag = diag::err_template_parameter_pack_non_pack;
8266 if (TemplateArgLoc.isValid()) {
8267 S.Diag(TemplateArgLoc,
8268 diag::err_template_arg_template_params_mismatch);
8269 NextDiag = diag::note_template_parameter_pack_non_pack;
8270 }
8271
8272 unsigned ParamKind = isa<TemplateTypeParmDecl>(New)? 0
8273 : isa<NonTypeTemplateParmDecl>(New)? 1
8274 : 2;
8275 S.Diag(New->getLocation(), NextDiag)
8276 << ParamKind << New->isParameterPack();
8277 S.Diag(Old->getLocation(), diag::note_template_parameter_pack_here)
8278 << ParamKind << Old->isParameterPack();
8279 }
8280
8281 return false;
8282 }
8283
8284 // For non-type template parameters, check the type of the parameter.
8285 if (NonTypeTemplateParmDecl *OldNTTP
8286 = dyn_cast<NonTypeTemplateParmDecl>(Old)) {
8287 NonTypeTemplateParmDecl *NewNTTP = cast<NonTypeTemplateParmDecl>(New);
8288
8289 // If we are matching a template template argument to a template
8290 // template parameter and one of the non-type template parameter types
8291 // is dependent, then we must wait until template instantiation time
8292 // to actually compare the arguments.
8293 if (Kind != Sema::TPL_TemplateTemplateArgumentMatch ||
8294 (!OldNTTP->getType()->isDependentType() &&
8295 !NewNTTP->getType()->isDependentType())) {
8296 // C++20 [temp.over.link]p6:
8297 // Two [non-type] template-parameters are equivalent [if] they have
8298 // equivalent types ignoring the use of type-constraints for
8299 // placeholder types
8300 QualType OldType = S.Context.getUnconstrainedType(OldNTTP->getType());
8301 QualType NewType = S.Context.getUnconstrainedType(NewNTTP->getType());
8302 if (!S.Context.hasSameType(OldType, NewType)) {
8303 if (Complain) {
8304 unsigned NextDiag = diag::err_template_nontype_parm_different_type;
8305 if (TemplateArgLoc.isValid()) {
8306 S.Diag(TemplateArgLoc,
8307 diag::err_template_arg_template_params_mismatch);
8308 NextDiag = diag::note_template_nontype_parm_different_type;
8309 }
8310 S.Diag(NewNTTP->getLocation(), NextDiag)
8311 << NewNTTP->getType()
8312 << (Kind != Sema::TPL_TemplateMatch);
8313 S.Diag(OldNTTP->getLocation(),
8314 diag::note_template_nontype_parm_prev_declaration)
8315 << OldNTTP->getType();
8316 }
8317
8318 return false;
8319 }
8320 }
8321 }
8322 // For template template parameters, check the template parameter types.
8323 // The template parameter lists of template template
8324 // parameters must agree.
8325 else if (TemplateTemplateParmDecl *OldTTP =
8326 dyn_cast<TemplateTemplateParmDecl>(Old)) {
8327 TemplateTemplateParmDecl *NewTTP = cast<TemplateTemplateParmDecl>(New);
8328 if (!S.TemplateParameterListsAreEqual(
8329 NewInstFrom, NewTTP->getTemplateParameters(), OldInstFrom,
8330 OldTTP->getTemplateParameters(), Complain,
8331 (Kind == Sema::TPL_TemplateMatch
8332 ? Sema::TPL_TemplateTemplateParmMatch
8333 : Kind),
8334 TemplateArgLoc))
8335 return false;
8336 }
8337
8338 if (Kind != Sema::TPL_TemplateParamsEquivalent &&
8339 Kind != Sema::TPL_TemplateTemplateArgumentMatch &&
8340 !isa<TemplateTemplateParmDecl>(Old)) {
8341 const Expr *NewC = nullptr, *OldC = nullptr;
8342
8343 if (isa<TemplateTypeParmDecl>(New)) {
8344 if (const auto *TC = cast<TemplateTypeParmDecl>(New)->getTypeConstraint())
8345 NewC = TC->getImmediatelyDeclaredConstraint();
8346 if (const auto *TC = cast<TemplateTypeParmDecl>(Old)->getTypeConstraint())
8347 OldC = TC->getImmediatelyDeclaredConstraint();
8348 } else if (isa<NonTypeTemplateParmDecl>(New)) {
8349 if (const Expr *E = cast<NonTypeTemplateParmDecl>(New)
8350 ->getPlaceholderTypeConstraint())
8351 NewC = E;
8352 if (const Expr *E = cast<NonTypeTemplateParmDecl>(Old)
8353 ->getPlaceholderTypeConstraint())
8354 OldC = E;
8355 } else
8356 llvm_unreachable("unexpected template parameter type");
8357
8358 auto Diagnose = [&] {
8359 S.Diag(NewC ? NewC->getBeginLoc() : New->getBeginLoc(),
8360 diag::err_template_different_type_constraint);
8361 S.Diag(OldC ? OldC->getBeginLoc() : Old->getBeginLoc(),
8362 diag::note_template_prev_declaration) << /*declaration*/0;
8363 };
8364
8365 if (!NewC != !OldC) {
8366 if (Complain)
8367 Diagnose();
8368 return false;
8369 }
8370
8371 if (NewC) {
8372 if (!S.AreConstraintExpressionsEqual(OldInstFrom, OldC, NewInstFrom,
8373 NewC)) {
8374 if (Complain)
8375 Diagnose();
8376 return false;
8377 }
8378 }
8379 }
8380
8381 return true;
8382 }
8383
8384 /// Diagnose a known arity mismatch when comparing template argument
8385 /// lists.
8386 static
DiagnoseTemplateParameterListArityMismatch(Sema & S,TemplateParameterList * New,TemplateParameterList * Old,Sema::TemplateParameterListEqualKind Kind,SourceLocation TemplateArgLoc)8387 void DiagnoseTemplateParameterListArityMismatch(Sema &S,
8388 TemplateParameterList *New,
8389 TemplateParameterList *Old,
8390 Sema::TemplateParameterListEqualKind Kind,
8391 SourceLocation TemplateArgLoc) {
8392 unsigned NextDiag = diag::err_template_param_list_different_arity;
8393 if (TemplateArgLoc.isValid()) {
8394 S.Diag(TemplateArgLoc, diag::err_template_arg_template_params_mismatch);
8395 NextDiag = diag::note_template_param_list_different_arity;
8396 }
8397 S.Diag(New->getTemplateLoc(), NextDiag)
8398 << (New->size() > Old->size())
8399 << (Kind != Sema::TPL_TemplateMatch)
8400 << SourceRange(New->getTemplateLoc(), New->getRAngleLoc());
8401 S.Diag(Old->getTemplateLoc(), diag::note_template_prev_declaration)
8402 << (Kind != Sema::TPL_TemplateMatch)
8403 << SourceRange(Old->getTemplateLoc(), Old->getRAngleLoc());
8404 }
8405
8406 /// Determine whether the given template parameter lists are
8407 /// equivalent.
8408 ///
8409 /// \param New The new template parameter list, typically written in the
8410 /// source code as part of a new template declaration.
8411 ///
8412 /// \param Old The old template parameter list, typically found via
8413 /// name lookup of the template declared with this template parameter
8414 /// list.
8415 ///
8416 /// \param Complain If true, this routine will produce a diagnostic if
8417 /// the template parameter lists are not equivalent.
8418 ///
8419 /// \param Kind describes how we are to match the template parameter lists.
8420 ///
8421 /// \param TemplateArgLoc If this source location is valid, then we
8422 /// are actually checking the template parameter list of a template
8423 /// argument (New) against the template parameter list of its
8424 /// corresponding template template parameter (Old). We produce
8425 /// slightly different diagnostics in this scenario.
8426 ///
8427 /// \returns True if the template parameter lists are equal, false
8428 /// otherwise.
TemplateParameterListsAreEqual(const TemplateCompareNewDeclInfo & NewInstFrom,TemplateParameterList * New,const NamedDecl * OldInstFrom,TemplateParameterList * Old,bool Complain,TemplateParameterListEqualKind Kind,SourceLocation TemplateArgLoc)8429 bool Sema::TemplateParameterListsAreEqual(
8430 const TemplateCompareNewDeclInfo &NewInstFrom, TemplateParameterList *New,
8431 const NamedDecl *OldInstFrom, TemplateParameterList *Old, bool Complain,
8432 TemplateParameterListEqualKind Kind, SourceLocation TemplateArgLoc) {
8433 if (Old->size() != New->size() && Kind != TPL_TemplateTemplateArgumentMatch) {
8434 if (Complain)
8435 DiagnoseTemplateParameterListArityMismatch(*this, New, Old, Kind,
8436 TemplateArgLoc);
8437
8438 return false;
8439 }
8440
8441 // C++0x [temp.arg.template]p3:
8442 // A template-argument matches a template template-parameter (call it P)
8443 // when each of the template parameters in the template-parameter-list of
8444 // the template-argument's corresponding class template or alias template
8445 // (call it A) matches the corresponding template parameter in the
8446 // template-parameter-list of P. [...]
8447 TemplateParameterList::iterator NewParm = New->begin();
8448 TemplateParameterList::iterator NewParmEnd = New->end();
8449 for (TemplateParameterList::iterator OldParm = Old->begin(),
8450 OldParmEnd = Old->end();
8451 OldParm != OldParmEnd; ++OldParm) {
8452 if (Kind != TPL_TemplateTemplateArgumentMatch ||
8453 !(*OldParm)->isTemplateParameterPack()) {
8454 if (NewParm == NewParmEnd) {
8455 if (Complain)
8456 DiagnoseTemplateParameterListArityMismatch(*this, New, Old, Kind,
8457 TemplateArgLoc);
8458
8459 return false;
8460 }
8461
8462 if (!MatchTemplateParameterKind(*this, *NewParm, NewInstFrom, *OldParm,
8463 OldInstFrom, Complain, Kind,
8464 TemplateArgLoc))
8465 return false;
8466
8467 ++NewParm;
8468 continue;
8469 }
8470
8471 // C++0x [temp.arg.template]p3:
8472 // [...] When P's template- parameter-list contains a template parameter
8473 // pack (14.5.3), the template parameter pack will match zero or more
8474 // template parameters or template parameter packs in the
8475 // template-parameter-list of A with the same type and form as the
8476 // template parameter pack in P (ignoring whether those template
8477 // parameters are template parameter packs).
8478 for (; NewParm != NewParmEnd; ++NewParm) {
8479 if (!MatchTemplateParameterKind(*this, *NewParm, NewInstFrom, *OldParm,
8480 OldInstFrom, Complain, Kind,
8481 TemplateArgLoc))
8482 return false;
8483 }
8484 }
8485
8486 // Make sure we exhausted all of the arguments.
8487 if (NewParm != NewParmEnd) {
8488 if (Complain)
8489 DiagnoseTemplateParameterListArityMismatch(*this, New, Old, Kind,
8490 TemplateArgLoc);
8491
8492 return false;
8493 }
8494
8495 if (Kind != TPL_TemplateTemplateArgumentMatch &&
8496 Kind != TPL_TemplateParamsEquivalent) {
8497 const Expr *NewRC = New->getRequiresClause();
8498 const Expr *OldRC = Old->getRequiresClause();
8499
8500 auto Diagnose = [&] {
8501 Diag(NewRC ? NewRC->getBeginLoc() : New->getTemplateLoc(),
8502 diag::err_template_different_requires_clause);
8503 Diag(OldRC ? OldRC->getBeginLoc() : Old->getTemplateLoc(),
8504 diag::note_template_prev_declaration) << /*declaration*/0;
8505 };
8506
8507 if (!NewRC != !OldRC) {
8508 if (Complain)
8509 Diagnose();
8510 return false;
8511 }
8512
8513 if (NewRC) {
8514 if (!AreConstraintExpressionsEqual(OldInstFrom, OldRC, NewInstFrom,
8515 NewRC)) {
8516 if (Complain)
8517 Diagnose();
8518 return false;
8519 }
8520 }
8521 }
8522
8523 return true;
8524 }
8525
8526 /// Check whether a template can be declared within this scope.
8527 ///
8528 /// If the template declaration is valid in this scope, returns
8529 /// false. Otherwise, issues a diagnostic and returns true.
8530 bool
CheckTemplateDeclScope(Scope * S,TemplateParameterList * TemplateParams)8531 Sema::CheckTemplateDeclScope(Scope *S, TemplateParameterList *TemplateParams) {
8532 if (!S)
8533 return false;
8534
8535 // Find the nearest enclosing declaration scope.
8536 while ((S->getFlags() & Scope::DeclScope) == 0 ||
8537 (S->getFlags() & Scope::TemplateParamScope) != 0)
8538 S = S->getParent();
8539
8540 // C++ [temp.pre]p6: [P2096]
8541 // A template, explicit specialization, or partial specialization shall not
8542 // have C linkage.
8543 DeclContext *Ctx = S->getEntity();
8544 if (Ctx && Ctx->isExternCContext()) {
8545 Diag(TemplateParams->getTemplateLoc(), diag::err_template_linkage)
8546 << TemplateParams->getSourceRange();
8547 if (const LinkageSpecDecl *LSD = Ctx->getExternCContext())
8548 Diag(LSD->getExternLoc(), diag::note_extern_c_begins_here);
8549 return true;
8550 }
8551 Ctx = Ctx ? Ctx->getRedeclContext() : nullptr;
8552
8553 // C++ [temp]p2:
8554 // A template-declaration can appear only as a namespace scope or
8555 // class scope declaration.
8556 // C++ [temp.expl.spec]p3:
8557 // An explicit specialization may be declared in any scope in which the
8558 // corresponding primary template may be defined.
8559 // C++ [temp.class.spec]p6: [P2096]
8560 // A partial specialization may be declared in any scope in which the
8561 // corresponding primary template may be defined.
8562 if (Ctx) {
8563 if (Ctx->isFileContext())
8564 return false;
8565 if (CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(Ctx)) {
8566 // C++ [temp.mem]p2:
8567 // A local class shall not have member templates.
8568 if (RD->isLocalClass())
8569 return Diag(TemplateParams->getTemplateLoc(),
8570 diag::err_template_inside_local_class)
8571 << TemplateParams->getSourceRange();
8572 else
8573 return false;
8574 }
8575 }
8576
8577 return Diag(TemplateParams->getTemplateLoc(),
8578 diag::err_template_outside_namespace_or_class_scope)
8579 << TemplateParams->getSourceRange();
8580 }
8581
8582 /// Determine what kind of template specialization the given declaration
8583 /// is.
getTemplateSpecializationKind(Decl * D)8584 static TemplateSpecializationKind getTemplateSpecializationKind(Decl *D) {
8585 if (!D)
8586 return TSK_Undeclared;
8587
8588 if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(D))
8589 return Record->getTemplateSpecializationKind();
8590 if (FunctionDecl *Function = dyn_cast<FunctionDecl>(D))
8591 return Function->getTemplateSpecializationKind();
8592 if (VarDecl *Var = dyn_cast<VarDecl>(D))
8593 return Var->getTemplateSpecializationKind();
8594
8595 return TSK_Undeclared;
8596 }
8597
8598 /// Check whether a specialization is well-formed in the current
8599 /// context.
8600 ///
8601 /// This routine determines whether a template specialization can be declared
8602 /// in the current context (C++ [temp.expl.spec]p2).
8603 ///
8604 /// \param S the semantic analysis object for which this check is being
8605 /// performed.
8606 ///
8607 /// \param Specialized the entity being specialized or instantiated, which
8608 /// may be a kind of template (class template, function template, etc.) or
8609 /// a member of a class template (member function, static data member,
8610 /// member class).
8611 ///
8612 /// \param PrevDecl the previous declaration of this entity, if any.
8613 ///
8614 /// \param Loc the location of the explicit specialization or instantiation of
8615 /// this entity.
8616 ///
8617 /// \param IsPartialSpecialization whether this is a partial specialization of
8618 /// a class template.
8619 ///
8620 /// \returns true if there was an error that we cannot recover from, false
8621 /// otherwise.
CheckTemplateSpecializationScope(Sema & S,NamedDecl * Specialized,NamedDecl * PrevDecl,SourceLocation Loc,bool IsPartialSpecialization)8622 static bool CheckTemplateSpecializationScope(Sema &S,
8623 NamedDecl *Specialized,
8624 NamedDecl *PrevDecl,
8625 SourceLocation Loc,
8626 bool IsPartialSpecialization) {
8627 // Keep these "kind" numbers in sync with the %select statements in the
8628 // various diagnostics emitted by this routine.
8629 int EntityKind = 0;
8630 if (isa<ClassTemplateDecl>(Specialized))
8631 EntityKind = IsPartialSpecialization? 1 : 0;
8632 else if (isa<VarTemplateDecl>(Specialized))
8633 EntityKind = IsPartialSpecialization ? 3 : 2;
8634 else if (isa<FunctionTemplateDecl>(Specialized))
8635 EntityKind = 4;
8636 else if (isa<CXXMethodDecl>(Specialized))
8637 EntityKind = 5;
8638 else if (isa<VarDecl>(Specialized))
8639 EntityKind = 6;
8640 else if (isa<RecordDecl>(Specialized))
8641 EntityKind = 7;
8642 else if (isa<EnumDecl>(Specialized) && S.getLangOpts().CPlusPlus11)
8643 EntityKind = 8;
8644 else {
8645 S.Diag(Loc, diag::err_template_spec_unknown_kind)
8646 << S.getLangOpts().CPlusPlus11;
8647 S.Diag(Specialized->getLocation(), diag::note_specialized_entity);
8648 return true;
8649 }
8650
8651 // C++ [temp.expl.spec]p2:
8652 // An explicit specialization may be declared in any scope in which
8653 // the corresponding primary template may be defined.
8654 if (S.CurContext->getRedeclContext()->isFunctionOrMethod()) {
8655 S.Diag(Loc, diag::err_template_spec_decl_function_scope)
8656 << Specialized;
8657 return true;
8658 }
8659
8660 // C++ [temp.class.spec]p6:
8661 // A class template partial specialization may be declared in any
8662 // scope in which the primary template may be defined.
8663 DeclContext *SpecializedContext =
8664 Specialized->getDeclContext()->getRedeclContext();
8665 DeclContext *DC = S.CurContext->getRedeclContext();
8666
8667 // Make sure that this redeclaration (or definition) occurs in the same
8668 // scope or an enclosing namespace.
8669 if (!(DC->isFileContext() ? DC->Encloses(SpecializedContext)
8670 : DC->Equals(SpecializedContext))) {
8671 if (isa<TranslationUnitDecl>(SpecializedContext))
8672 S.Diag(Loc, diag::err_template_spec_redecl_global_scope)
8673 << EntityKind << Specialized;
8674 else {
8675 auto *ND = cast<NamedDecl>(SpecializedContext);
8676 int Diag = diag::err_template_spec_redecl_out_of_scope;
8677 if (S.getLangOpts().MicrosoftExt && !DC->isRecord())
8678 Diag = diag::ext_ms_template_spec_redecl_out_of_scope;
8679 S.Diag(Loc, Diag) << EntityKind << Specialized
8680 << ND << isa<CXXRecordDecl>(ND);
8681 }
8682
8683 S.Diag(Specialized->getLocation(), diag::note_specialized_entity);
8684
8685 // Don't allow specializing in the wrong class during error recovery.
8686 // Otherwise, things can go horribly wrong.
8687 if (DC->isRecord())
8688 return true;
8689 }
8690
8691 return false;
8692 }
8693
findTemplateParameterInType(unsigned Depth,Expr * E)8694 static SourceRange findTemplateParameterInType(unsigned Depth, Expr *E) {
8695 if (!E->isTypeDependent())
8696 return SourceLocation();
8697 DependencyChecker Checker(Depth, /*IgnoreNonTypeDependent*/true);
8698 Checker.TraverseStmt(E);
8699 if (Checker.MatchLoc.isInvalid())
8700 return E->getSourceRange();
8701 return Checker.MatchLoc;
8702 }
8703
findTemplateParameter(unsigned Depth,TypeLoc TL)8704 static SourceRange findTemplateParameter(unsigned Depth, TypeLoc TL) {
8705 if (!TL.getType()->isDependentType())
8706 return SourceLocation();
8707 DependencyChecker Checker(Depth, /*IgnoreNonTypeDependent*/true);
8708 Checker.TraverseTypeLoc(TL);
8709 if (Checker.MatchLoc.isInvalid())
8710 return TL.getSourceRange();
8711 return Checker.MatchLoc;
8712 }
8713
8714 /// Subroutine of Sema::CheckTemplatePartialSpecializationArgs
8715 /// that checks non-type template partial specialization arguments.
CheckNonTypeTemplatePartialSpecializationArgs(Sema & S,SourceLocation TemplateNameLoc,NonTypeTemplateParmDecl * Param,const TemplateArgument * Args,unsigned NumArgs,bool IsDefaultArgument)8716 static bool CheckNonTypeTemplatePartialSpecializationArgs(
8717 Sema &S, SourceLocation TemplateNameLoc, NonTypeTemplateParmDecl *Param,
8718 const TemplateArgument *Args, unsigned NumArgs, bool IsDefaultArgument) {
8719 for (unsigned I = 0; I != NumArgs; ++I) {
8720 if (Args[I].getKind() == TemplateArgument::Pack) {
8721 if (CheckNonTypeTemplatePartialSpecializationArgs(
8722 S, TemplateNameLoc, Param, Args[I].pack_begin(),
8723 Args[I].pack_size(), IsDefaultArgument))
8724 return true;
8725
8726 continue;
8727 }
8728
8729 if (Args[I].getKind() != TemplateArgument::Expression)
8730 continue;
8731
8732 Expr *ArgExpr = Args[I].getAsExpr();
8733
8734 // We can have a pack expansion of any of the bullets below.
8735 if (PackExpansionExpr *Expansion = dyn_cast<PackExpansionExpr>(ArgExpr))
8736 ArgExpr = Expansion->getPattern();
8737
8738 // Strip off any implicit casts we added as part of type checking.
8739 while (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(ArgExpr))
8740 ArgExpr = ICE->getSubExpr();
8741
8742 // C++ [temp.class.spec]p8:
8743 // A non-type argument is non-specialized if it is the name of a
8744 // non-type parameter. All other non-type arguments are
8745 // specialized.
8746 //
8747 // Below, we check the two conditions that only apply to
8748 // specialized non-type arguments, so skip any non-specialized
8749 // arguments.
8750 if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(ArgExpr))
8751 if (isa<NonTypeTemplateParmDecl>(DRE->getDecl()))
8752 continue;
8753
8754 // C++ [temp.class.spec]p9:
8755 // Within the argument list of a class template partial
8756 // specialization, the following restrictions apply:
8757 // -- A partially specialized non-type argument expression
8758 // shall not involve a template parameter of the partial
8759 // specialization except when the argument expression is a
8760 // simple identifier.
8761 // -- The type of a template parameter corresponding to a
8762 // specialized non-type argument shall not be dependent on a
8763 // parameter of the specialization.
8764 // DR1315 removes the first bullet, leaving an incoherent set of rules.
8765 // We implement a compromise between the original rules and DR1315:
8766 // -- A specialized non-type template argument shall not be
8767 // type-dependent and the corresponding template parameter
8768 // shall have a non-dependent type.
8769 SourceRange ParamUseRange =
8770 findTemplateParameterInType(Param->getDepth(), ArgExpr);
8771 if (ParamUseRange.isValid()) {
8772 if (IsDefaultArgument) {
8773 S.Diag(TemplateNameLoc,
8774 diag::err_dependent_non_type_arg_in_partial_spec);
8775 S.Diag(ParamUseRange.getBegin(),
8776 diag::note_dependent_non_type_default_arg_in_partial_spec)
8777 << ParamUseRange;
8778 } else {
8779 S.Diag(ParamUseRange.getBegin(),
8780 diag::err_dependent_non_type_arg_in_partial_spec)
8781 << ParamUseRange;
8782 }
8783 return true;
8784 }
8785
8786 ParamUseRange = findTemplateParameter(
8787 Param->getDepth(), Param->getTypeSourceInfo()->getTypeLoc());
8788 if (ParamUseRange.isValid()) {
8789 S.Diag(IsDefaultArgument ? TemplateNameLoc : ArgExpr->getBeginLoc(),
8790 diag::err_dependent_typed_non_type_arg_in_partial_spec)
8791 << Param->getType();
8792 S.NoteTemplateParameterLocation(*Param);
8793 return true;
8794 }
8795 }
8796
8797 return false;
8798 }
8799
8800 /// Check the non-type template arguments of a class template
8801 /// partial specialization according to C++ [temp.class.spec]p9.
8802 ///
8803 /// \param TemplateNameLoc the location of the template name.
8804 /// \param PrimaryTemplate the template parameters of the primary class
8805 /// template.
8806 /// \param NumExplicit the number of explicitly-specified template arguments.
8807 /// \param TemplateArgs the template arguments of the class template
8808 /// partial specialization.
8809 ///
8810 /// \returns \c true if there was an error, \c false otherwise.
CheckTemplatePartialSpecializationArgs(SourceLocation TemplateNameLoc,TemplateDecl * PrimaryTemplate,unsigned NumExplicit,ArrayRef<TemplateArgument> TemplateArgs)8811 bool Sema::CheckTemplatePartialSpecializationArgs(
8812 SourceLocation TemplateNameLoc, TemplateDecl *PrimaryTemplate,
8813 unsigned NumExplicit, ArrayRef<TemplateArgument> TemplateArgs) {
8814 // We have to be conservative when checking a template in a dependent
8815 // context.
8816 if (PrimaryTemplate->getDeclContext()->isDependentContext())
8817 return false;
8818
8819 TemplateParameterList *TemplateParams =
8820 PrimaryTemplate->getTemplateParameters();
8821 for (unsigned I = 0, N = TemplateParams->size(); I != N; ++I) {
8822 NonTypeTemplateParmDecl *Param
8823 = dyn_cast<NonTypeTemplateParmDecl>(TemplateParams->getParam(I));
8824 if (!Param)
8825 continue;
8826
8827 if (CheckNonTypeTemplatePartialSpecializationArgs(*this, TemplateNameLoc,
8828 Param, &TemplateArgs[I],
8829 1, I >= NumExplicit))
8830 return true;
8831 }
8832
8833 return false;
8834 }
8835
ActOnClassTemplateSpecialization(Scope * S,unsigned TagSpec,TagUseKind TUK,SourceLocation KWLoc,SourceLocation ModulePrivateLoc,CXXScopeSpec & SS,TemplateIdAnnotation & TemplateId,const ParsedAttributesView & Attr,MultiTemplateParamsArg TemplateParameterLists,SkipBodyInfo * SkipBody)8836 DeclResult Sema::ActOnClassTemplateSpecialization(
8837 Scope *S, unsigned TagSpec, TagUseKind TUK, SourceLocation KWLoc,
8838 SourceLocation ModulePrivateLoc, CXXScopeSpec &SS,
8839 TemplateIdAnnotation &TemplateId, const ParsedAttributesView &Attr,
8840 MultiTemplateParamsArg TemplateParameterLists, SkipBodyInfo *SkipBody) {
8841 assert(TUK != TUK_Reference && "References are not specializations");
8842
8843 // NOTE: KWLoc is the location of the tag keyword. This will instead
8844 // store the location of the outermost template keyword in the declaration.
8845 SourceLocation TemplateKWLoc = TemplateParameterLists.size() > 0
8846 ? TemplateParameterLists[0]->getTemplateLoc() : KWLoc;
8847 SourceLocation TemplateNameLoc = TemplateId.TemplateNameLoc;
8848 SourceLocation LAngleLoc = TemplateId.LAngleLoc;
8849 SourceLocation RAngleLoc = TemplateId.RAngleLoc;
8850
8851 // Find the class template we're specializing
8852 TemplateName Name = TemplateId.Template.get();
8853 ClassTemplateDecl *ClassTemplate
8854 = dyn_cast_or_null<ClassTemplateDecl>(Name.getAsTemplateDecl());
8855
8856 if (!ClassTemplate) {
8857 Diag(TemplateNameLoc, diag::err_not_class_template_specialization)
8858 << (Name.getAsTemplateDecl() &&
8859 isa<TemplateTemplateParmDecl>(Name.getAsTemplateDecl()));
8860 return true;
8861 }
8862
8863 bool isMemberSpecialization = false;
8864 bool isPartialSpecialization = false;
8865
8866 // Check the validity of the template headers that introduce this
8867 // template.
8868 // FIXME: We probably shouldn't complain about these headers for
8869 // friend declarations.
8870 bool Invalid = false;
8871 TemplateParameterList *TemplateParams =
8872 MatchTemplateParametersToScopeSpecifier(
8873 KWLoc, TemplateNameLoc, SS, &TemplateId,
8874 TemplateParameterLists, TUK == TUK_Friend, isMemberSpecialization,
8875 Invalid);
8876 if (Invalid)
8877 return true;
8878
8879 // Check that we can declare a template specialization here.
8880 if (TemplateParams && CheckTemplateDeclScope(S, TemplateParams))
8881 return true;
8882
8883 if (TemplateParams && TemplateParams->size() > 0) {
8884 isPartialSpecialization = true;
8885
8886 if (TUK == TUK_Friend) {
8887 Diag(KWLoc, diag::err_partial_specialization_friend)
8888 << SourceRange(LAngleLoc, RAngleLoc);
8889 return true;
8890 }
8891
8892 // C++ [temp.class.spec]p10:
8893 // The template parameter list of a specialization shall not
8894 // contain default template argument values.
8895 for (unsigned I = 0, N = TemplateParams->size(); I != N; ++I) {
8896 Decl *Param = TemplateParams->getParam(I);
8897 if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(Param)) {
8898 if (TTP->hasDefaultArgument()) {
8899 Diag(TTP->getDefaultArgumentLoc(),
8900 diag::err_default_arg_in_partial_spec);
8901 TTP->removeDefaultArgument();
8902 }
8903 } else if (NonTypeTemplateParmDecl *NTTP
8904 = dyn_cast<NonTypeTemplateParmDecl>(Param)) {
8905 if (Expr *DefArg = NTTP->getDefaultArgument()) {
8906 Diag(NTTP->getDefaultArgumentLoc(),
8907 diag::err_default_arg_in_partial_spec)
8908 << DefArg->getSourceRange();
8909 NTTP->removeDefaultArgument();
8910 }
8911 } else {
8912 TemplateTemplateParmDecl *TTP = cast<TemplateTemplateParmDecl>(Param);
8913 if (TTP->hasDefaultArgument()) {
8914 Diag(TTP->getDefaultArgument().getLocation(),
8915 diag::err_default_arg_in_partial_spec)
8916 << TTP->getDefaultArgument().getSourceRange();
8917 TTP->removeDefaultArgument();
8918 }
8919 }
8920 }
8921 } else if (TemplateParams) {
8922 if (TUK == TUK_Friend)
8923 Diag(KWLoc, diag::err_template_spec_friend)
8924 << FixItHint::CreateRemoval(
8925 SourceRange(TemplateParams->getTemplateLoc(),
8926 TemplateParams->getRAngleLoc()))
8927 << SourceRange(LAngleLoc, RAngleLoc);
8928 } else {
8929 assert(TUK == TUK_Friend && "should have a 'template<>' for this decl");
8930 }
8931
8932 // Check that the specialization uses the same tag kind as the
8933 // original template.
8934 TagTypeKind Kind = TypeWithKeyword::getTagTypeKindForTypeSpec(TagSpec);
8935 assert(Kind != TagTypeKind::Enum &&
8936 "Invalid enum tag in class template spec!");
8937 if (!isAcceptableTagRedeclaration(ClassTemplate->getTemplatedDecl(),
8938 Kind, TUK == TUK_Definition, KWLoc,
8939 ClassTemplate->getIdentifier())) {
8940 Diag(KWLoc, diag::err_use_with_wrong_tag)
8941 << ClassTemplate
8942 << FixItHint::CreateReplacement(KWLoc,
8943 ClassTemplate->getTemplatedDecl()->getKindName());
8944 Diag(ClassTemplate->getTemplatedDecl()->getLocation(),
8945 diag::note_previous_use);
8946 Kind = ClassTemplate->getTemplatedDecl()->getTagKind();
8947 }
8948
8949 // Translate the parser's template argument list in our AST format.
8950 TemplateArgumentListInfo TemplateArgs =
8951 makeTemplateArgumentListInfo(*this, TemplateId);
8952
8953 // Check for unexpanded parameter packs in any of the template arguments.
8954 for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I)
8955 if (DiagnoseUnexpandedParameterPack(TemplateArgs[I],
8956 isPartialSpecialization
8957 ? UPPC_PartialSpecialization
8958 : UPPC_ExplicitSpecialization))
8959 return true;
8960
8961 // Check that the template argument list is well-formed for this
8962 // template.
8963 SmallVector<TemplateArgument, 4> SugaredConverted, CanonicalConverted;
8964 if (CheckTemplateArgumentList(ClassTemplate, TemplateNameLoc, TemplateArgs,
8965 false, SugaredConverted, CanonicalConverted,
8966 /*UpdateArgsWithConversions=*/true))
8967 return true;
8968
8969 // Find the class template (partial) specialization declaration that
8970 // corresponds to these arguments.
8971 if (isPartialSpecialization) {
8972 if (CheckTemplatePartialSpecializationArgs(TemplateNameLoc, ClassTemplate,
8973 TemplateArgs.size(),
8974 CanonicalConverted))
8975 return true;
8976
8977 // FIXME: Move this to CheckTemplatePartialSpecializationArgs so we
8978 // also do it during instantiation.
8979 if (!Name.isDependent() &&
8980 !TemplateSpecializationType::anyDependentTemplateArguments(
8981 TemplateArgs, CanonicalConverted)) {
8982 Diag(TemplateNameLoc, diag::err_partial_spec_fully_specialized)
8983 << ClassTemplate->getDeclName();
8984 isPartialSpecialization = false;
8985 }
8986 }
8987
8988 void *InsertPos = nullptr;
8989 ClassTemplateSpecializationDecl *PrevDecl = nullptr;
8990
8991 if (isPartialSpecialization)
8992 PrevDecl = ClassTemplate->findPartialSpecialization(
8993 CanonicalConverted, TemplateParams, InsertPos);
8994 else
8995 PrevDecl = ClassTemplate->findSpecialization(CanonicalConverted, InsertPos);
8996
8997 ClassTemplateSpecializationDecl *Specialization = nullptr;
8998
8999 // Check whether we can declare a class template specialization in
9000 // the current scope.
9001 if (TUK != TUK_Friend &&
9002 CheckTemplateSpecializationScope(*this, ClassTemplate, PrevDecl,
9003 TemplateNameLoc,
9004 isPartialSpecialization))
9005 return true;
9006
9007 // The canonical type
9008 QualType CanonType;
9009 if (isPartialSpecialization) {
9010 // Build the canonical type that describes the converted template
9011 // arguments of the class template partial specialization.
9012 TemplateName CanonTemplate = Context.getCanonicalTemplateName(Name);
9013 CanonType = Context.getTemplateSpecializationType(CanonTemplate,
9014 CanonicalConverted);
9015
9016 if (Context.hasSameType(CanonType,
9017 ClassTemplate->getInjectedClassNameSpecialization()) &&
9018 (!Context.getLangOpts().CPlusPlus20 ||
9019 !TemplateParams->hasAssociatedConstraints())) {
9020 // C++ [temp.class.spec]p9b3:
9021 //
9022 // -- The argument list of the specialization shall not be identical
9023 // to the implicit argument list of the primary template.
9024 //
9025 // This rule has since been removed, because it's redundant given DR1495,
9026 // but we keep it because it produces better diagnostics and recovery.
9027 Diag(TemplateNameLoc, diag::err_partial_spec_args_match_primary_template)
9028 << /*class template*/0 << (TUK == TUK_Definition)
9029 << FixItHint::CreateRemoval(SourceRange(LAngleLoc, RAngleLoc));
9030 return CheckClassTemplate(S, TagSpec, TUK, KWLoc, SS,
9031 ClassTemplate->getIdentifier(),
9032 TemplateNameLoc,
9033 Attr,
9034 TemplateParams,
9035 AS_none, /*ModulePrivateLoc=*/SourceLocation(),
9036 /*FriendLoc*/SourceLocation(),
9037 TemplateParameterLists.size() - 1,
9038 TemplateParameterLists.data());
9039 }
9040
9041 // Create a new class template partial specialization declaration node.
9042 ClassTemplatePartialSpecializationDecl *PrevPartial
9043 = cast_or_null<ClassTemplatePartialSpecializationDecl>(PrevDecl);
9044 ClassTemplatePartialSpecializationDecl *Partial =
9045 ClassTemplatePartialSpecializationDecl::Create(
9046 Context, Kind, ClassTemplate->getDeclContext(), KWLoc,
9047 TemplateNameLoc, TemplateParams, ClassTemplate, CanonicalConverted,
9048 TemplateArgs, CanonType, PrevPartial);
9049 SetNestedNameSpecifier(*this, Partial, SS);
9050 if (TemplateParameterLists.size() > 1 && SS.isSet()) {
9051 Partial->setTemplateParameterListsInfo(
9052 Context, TemplateParameterLists.drop_back(1));
9053 }
9054
9055 if (!PrevPartial)
9056 ClassTemplate->AddPartialSpecialization(Partial, InsertPos);
9057 Specialization = Partial;
9058
9059 // If we are providing an explicit specialization of a member class
9060 // template specialization, make a note of that.
9061 if (PrevPartial && PrevPartial->getInstantiatedFromMember())
9062 PrevPartial->setMemberSpecialization();
9063
9064 CheckTemplatePartialSpecialization(Partial);
9065 } else {
9066 // Create a new class template specialization declaration node for
9067 // this explicit specialization or friend declaration.
9068 Specialization = ClassTemplateSpecializationDecl::Create(
9069 Context, Kind, ClassTemplate->getDeclContext(), KWLoc, TemplateNameLoc,
9070 ClassTemplate, CanonicalConverted, PrevDecl);
9071 SetNestedNameSpecifier(*this, Specialization, SS);
9072 if (TemplateParameterLists.size() > 0) {
9073 Specialization->setTemplateParameterListsInfo(Context,
9074 TemplateParameterLists);
9075 }
9076
9077 if (!PrevDecl)
9078 ClassTemplate->AddSpecialization(Specialization, InsertPos);
9079
9080 if (CurContext->isDependentContext()) {
9081 TemplateName CanonTemplate = Context.getCanonicalTemplateName(Name);
9082 CanonType = Context.getTemplateSpecializationType(CanonTemplate,
9083 CanonicalConverted);
9084 } else {
9085 CanonType = Context.getTypeDeclType(Specialization);
9086 }
9087 }
9088
9089 // C++ [temp.expl.spec]p6:
9090 // If a template, a member template or the member of a class template is
9091 // explicitly specialized then that specialization shall be declared
9092 // before the first use of that specialization that would cause an implicit
9093 // instantiation to take place, in every translation unit in which such a
9094 // use occurs; no diagnostic is required.
9095 if (PrevDecl && PrevDecl->getPointOfInstantiation().isValid()) {
9096 bool Okay = false;
9097 for (Decl *Prev = PrevDecl; Prev; Prev = Prev->getPreviousDecl()) {
9098 // Is there any previous explicit specialization declaration?
9099 if (getTemplateSpecializationKind(Prev) == TSK_ExplicitSpecialization) {
9100 Okay = true;
9101 break;
9102 }
9103 }
9104
9105 if (!Okay) {
9106 SourceRange Range(TemplateNameLoc, RAngleLoc);
9107 Diag(TemplateNameLoc, diag::err_specialization_after_instantiation)
9108 << Context.getTypeDeclType(Specialization) << Range;
9109
9110 Diag(PrevDecl->getPointOfInstantiation(),
9111 diag::note_instantiation_required_here)
9112 << (PrevDecl->getTemplateSpecializationKind()
9113 != TSK_ImplicitInstantiation);
9114 return true;
9115 }
9116 }
9117
9118 // If this is not a friend, note that this is an explicit specialization.
9119 if (TUK != TUK_Friend)
9120 Specialization->setSpecializationKind(TSK_ExplicitSpecialization);
9121
9122 // Check that this isn't a redefinition of this specialization.
9123 if (TUK == TUK_Definition) {
9124 RecordDecl *Def = Specialization->getDefinition();
9125 NamedDecl *Hidden = nullptr;
9126 if (Def && SkipBody && !hasVisibleDefinition(Def, &Hidden)) {
9127 SkipBody->ShouldSkip = true;
9128 SkipBody->Previous = Def;
9129 makeMergedDefinitionVisible(Hidden);
9130 } else if (Def) {
9131 SourceRange Range(TemplateNameLoc, RAngleLoc);
9132 Diag(TemplateNameLoc, diag::err_redefinition) << Specialization << Range;
9133 Diag(Def->getLocation(), diag::note_previous_definition);
9134 Specialization->setInvalidDecl();
9135 return true;
9136 }
9137 }
9138
9139 ProcessDeclAttributeList(S, Specialization, Attr);
9140
9141 // Add alignment attributes if necessary; these attributes are checked when
9142 // the ASTContext lays out the structure.
9143 if (TUK == TUK_Definition && (!SkipBody || !SkipBody->ShouldSkip)) {
9144 AddAlignmentAttributesForRecord(Specialization);
9145 AddMsStructLayoutForRecord(Specialization);
9146 }
9147
9148 if (ModulePrivateLoc.isValid())
9149 Diag(Specialization->getLocation(), diag::err_module_private_specialization)
9150 << (isPartialSpecialization? 1 : 0)
9151 << FixItHint::CreateRemoval(ModulePrivateLoc);
9152
9153 // Build the fully-sugared type for this class template
9154 // specialization as the user wrote in the specialization
9155 // itself. This means that we'll pretty-print the type retrieved
9156 // from the specialization's declaration the way that the user
9157 // actually wrote the specialization, rather than formatting the
9158 // name based on the "canonical" representation used to store the
9159 // template arguments in the specialization.
9160 TypeSourceInfo *WrittenTy
9161 = Context.getTemplateSpecializationTypeInfo(Name, TemplateNameLoc,
9162 TemplateArgs, CanonType);
9163 if (TUK != TUK_Friend) {
9164 Specialization->setTypeAsWritten(WrittenTy);
9165 Specialization->setTemplateKeywordLoc(TemplateKWLoc);
9166 }
9167
9168 // C++ [temp.expl.spec]p9:
9169 // A template explicit specialization is in the scope of the
9170 // namespace in which the template was defined.
9171 //
9172 // We actually implement this paragraph where we set the semantic
9173 // context (in the creation of the ClassTemplateSpecializationDecl),
9174 // but we also maintain the lexical context where the actual
9175 // definition occurs.
9176 Specialization->setLexicalDeclContext(CurContext);
9177
9178 // We may be starting the definition of this specialization.
9179 if (TUK == TUK_Definition && (!SkipBody || !SkipBody->ShouldSkip))
9180 Specialization->startDefinition();
9181
9182 if (TUK == TUK_Friend) {
9183 FriendDecl *Friend = FriendDecl::Create(Context, CurContext,
9184 TemplateNameLoc,
9185 WrittenTy,
9186 /*FIXME:*/KWLoc);
9187 Friend->setAccess(AS_public);
9188 CurContext->addDecl(Friend);
9189 } else {
9190 // Add the specialization into its lexical context, so that it can
9191 // be seen when iterating through the list of declarations in that
9192 // context. However, specializations are not found by name lookup.
9193 CurContext->addDecl(Specialization);
9194 }
9195
9196 if (SkipBody && SkipBody->ShouldSkip)
9197 return SkipBody->Previous;
9198
9199 return Specialization;
9200 }
9201
ActOnTemplateDeclarator(Scope * S,MultiTemplateParamsArg TemplateParameterLists,Declarator & D)9202 Decl *Sema::ActOnTemplateDeclarator(Scope *S,
9203 MultiTemplateParamsArg TemplateParameterLists,
9204 Declarator &D) {
9205 Decl *NewDecl = HandleDeclarator(S, D, TemplateParameterLists);
9206 ActOnDocumentableDecl(NewDecl);
9207 return NewDecl;
9208 }
9209
ActOnConceptDefinition(Scope * S,MultiTemplateParamsArg TemplateParameterLists,IdentifierInfo * Name,SourceLocation NameLoc,Expr * ConstraintExpr)9210 Decl *Sema::ActOnConceptDefinition(Scope *S,
9211 MultiTemplateParamsArg TemplateParameterLists,
9212 IdentifierInfo *Name, SourceLocation NameLoc,
9213 Expr *ConstraintExpr) {
9214 DeclContext *DC = CurContext;
9215
9216 if (!DC->getRedeclContext()->isFileContext()) {
9217 Diag(NameLoc,
9218 diag::err_concept_decls_may_only_appear_in_global_namespace_scope);
9219 return nullptr;
9220 }
9221
9222 if (TemplateParameterLists.size() > 1) {
9223 Diag(NameLoc, diag::err_concept_extra_headers);
9224 return nullptr;
9225 }
9226
9227 TemplateParameterList *Params = TemplateParameterLists.front();
9228
9229 if (Params->size() == 0) {
9230 Diag(NameLoc, diag::err_concept_no_parameters);
9231 return nullptr;
9232 }
9233
9234 // Ensure that the parameter pack, if present, is the last parameter in the
9235 // template.
9236 for (TemplateParameterList::const_iterator ParamIt = Params->begin(),
9237 ParamEnd = Params->end();
9238 ParamIt != ParamEnd; ++ParamIt) {
9239 Decl const *Param = *ParamIt;
9240 if (Param->isParameterPack()) {
9241 if (++ParamIt == ParamEnd)
9242 break;
9243 Diag(Param->getLocation(),
9244 diag::err_template_param_pack_must_be_last_template_parameter);
9245 return nullptr;
9246 }
9247 }
9248
9249 if (DiagnoseUnexpandedParameterPack(ConstraintExpr))
9250 return nullptr;
9251
9252 ConceptDecl *NewDecl =
9253 ConceptDecl::Create(Context, DC, NameLoc, Name, Params, ConstraintExpr);
9254
9255 if (NewDecl->hasAssociatedConstraints()) {
9256 // C++2a [temp.concept]p4:
9257 // A concept shall not have associated constraints.
9258 Diag(NameLoc, diag::err_concept_no_associated_constraints);
9259 NewDecl->setInvalidDecl();
9260 }
9261
9262 // Check for conflicting previous declaration.
9263 DeclarationNameInfo NameInfo(NewDecl->getDeclName(), NameLoc);
9264 LookupResult Previous(*this, NameInfo, LookupOrdinaryName,
9265 forRedeclarationInCurContext());
9266 LookupName(Previous, S);
9267 FilterLookupForScope(Previous, DC, S, /*ConsiderLinkage=*/false,
9268 /*AllowInlineNamespace*/false);
9269 bool AddToScope = true;
9270 CheckConceptRedefinition(NewDecl, Previous, AddToScope);
9271
9272 ActOnDocumentableDecl(NewDecl);
9273 if (AddToScope)
9274 PushOnScopeChains(NewDecl, S);
9275 return NewDecl;
9276 }
9277
CheckConceptRedefinition(ConceptDecl * NewDecl,LookupResult & Previous,bool & AddToScope)9278 void Sema::CheckConceptRedefinition(ConceptDecl *NewDecl,
9279 LookupResult &Previous, bool &AddToScope) {
9280 AddToScope = true;
9281
9282 if (Previous.empty())
9283 return;
9284
9285 auto *OldConcept = dyn_cast<ConceptDecl>(Previous.getRepresentativeDecl()->getUnderlyingDecl());
9286 if (!OldConcept) {
9287 auto *Old = Previous.getRepresentativeDecl();
9288 Diag(NewDecl->getLocation(), diag::err_redefinition_different_kind)
9289 << NewDecl->getDeclName();
9290 notePreviousDefinition(Old, NewDecl->getLocation());
9291 AddToScope = false;
9292 return;
9293 }
9294 // Check if we can merge with a concept declaration.
9295 bool IsSame = Context.isSameEntity(NewDecl, OldConcept);
9296 if (!IsSame) {
9297 Diag(NewDecl->getLocation(), diag::err_redefinition_different_concept)
9298 << NewDecl->getDeclName();
9299 notePreviousDefinition(OldConcept, NewDecl->getLocation());
9300 AddToScope = false;
9301 return;
9302 }
9303 if (hasReachableDefinition(OldConcept) &&
9304 IsRedefinitionInModule(NewDecl, OldConcept)) {
9305 Diag(NewDecl->getLocation(), diag::err_redefinition)
9306 << NewDecl->getDeclName();
9307 notePreviousDefinition(OldConcept, NewDecl->getLocation());
9308 AddToScope = false;
9309 return;
9310 }
9311 if (!Previous.isSingleResult()) {
9312 // FIXME: we should produce an error in case of ambig and failed lookups.
9313 // Other decls (e.g. namespaces) also have this shortcoming.
9314 return;
9315 }
9316 // We unwrap canonical decl late to check for module visibility.
9317 Context.setPrimaryMergedDecl(NewDecl, OldConcept->getCanonicalDecl());
9318 }
9319
9320 /// \brief Strips various properties off an implicit instantiation
9321 /// that has just been explicitly specialized.
StripImplicitInstantiation(NamedDecl * D,bool MinGW)9322 static void StripImplicitInstantiation(NamedDecl *D, bool MinGW) {
9323 if (MinGW || (isa<FunctionDecl>(D) &&
9324 cast<FunctionDecl>(D)->isFunctionTemplateSpecialization()))
9325 D->dropAttrs<DLLImportAttr, DLLExportAttr>();
9326
9327 if (FunctionDecl *FD = dyn_cast<FunctionDecl>(D))
9328 FD->setInlineSpecified(false);
9329 }
9330
9331 /// Compute the diagnostic location for an explicit instantiation
9332 // declaration or definition.
DiagLocForExplicitInstantiation(NamedDecl * D,SourceLocation PointOfInstantiation)9333 static SourceLocation DiagLocForExplicitInstantiation(
9334 NamedDecl* D, SourceLocation PointOfInstantiation) {
9335 // Explicit instantiations following a specialization have no effect and
9336 // hence no PointOfInstantiation. In that case, walk decl backwards
9337 // until a valid name loc is found.
9338 SourceLocation PrevDiagLoc = PointOfInstantiation;
9339 for (Decl *Prev = D; Prev && !PrevDiagLoc.isValid();
9340 Prev = Prev->getPreviousDecl()) {
9341 PrevDiagLoc = Prev->getLocation();
9342 }
9343 assert(PrevDiagLoc.isValid() &&
9344 "Explicit instantiation without point of instantiation?");
9345 return PrevDiagLoc;
9346 }
9347
9348 /// Diagnose cases where we have an explicit template specialization
9349 /// before/after an explicit template instantiation, producing diagnostics
9350 /// for those cases where they are required and determining whether the
9351 /// new specialization/instantiation will have any effect.
9352 ///
9353 /// \param NewLoc the location of the new explicit specialization or
9354 /// instantiation.
9355 ///
9356 /// \param NewTSK the kind of the new explicit specialization or instantiation.
9357 ///
9358 /// \param PrevDecl the previous declaration of the entity.
9359 ///
9360 /// \param PrevTSK the kind of the old explicit specialization or instantiatin.
9361 ///
9362 /// \param PrevPointOfInstantiation if valid, indicates where the previous
9363 /// declaration was instantiated (either implicitly or explicitly).
9364 ///
9365 /// \param HasNoEffect will be set to true to indicate that the new
9366 /// specialization or instantiation has no effect and should be ignored.
9367 ///
9368 /// \returns true if there was an error that should prevent the introduction of
9369 /// the new declaration into the AST, false otherwise.
9370 bool
CheckSpecializationInstantiationRedecl(SourceLocation NewLoc,TemplateSpecializationKind NewTSK,NamedDecl * PrevDecl,TemplateSpecializationKind PrevTSK,SourceLocation PrevPointOfInstantiation,bool & HasNoEffect)9371 Sema::CheckSpecializationInstantiationRedecl(SourceLocation NewLoc,
9372 TemplateSpecializationKind NewTSK,
9373 NamedDecl *PrevDecl,
9374 TemplateSpecializationKind PrevTSK,
9375 SourceLocation PrevPointOfInstantiation,
9376 bool &HasNoEffect) {
9377 HasNoEffect = false;
9378
9379 switch (NewTSK) {
9380 case TSK_Undeclared:
9381 case TSK_ImplicitInstantiation:
9382 assert(
9383 (PrevTSK == TSK_Undeclared || PrevTSK == TSK_ImplicitInstantiation) &&
9384 "previous declaration must be implicit!");
9385 return false;
9386
9387 case TSK_ExplicitSpecialization:
9388 switch (PrevTSK) {
9389 case TSK_Undeclared:
9390 case TSK_ExplicitSpecialization:
9391 // Okay, we're just specializing something that is either already
9392 // explicitly specialized or has merely been mentioned without any
9393 // instantiation.
9394 return false;
9395
9396 case TSK_ImplicitInstantiation:
9397 if (PrevPointOfInstantiation.isInvalid()) {
9398 // The declaration itself has not actually been instantiated, so it is
9399 // still okay to specialize it.
9400 StripImplicitInstantiation(
9401 PrevDecl,
9402 Context.getTargetInfo().getTriple().isWindowsGNUEnvironment());
9403 return false;
9404 }
9405 // Fall through
9406 [[fallthrough]];
9407
9408 case TSK_ExplicitInstantiationDeclaration:
9409 case TSK_ExplicitInstantiationDefinition:
9410 assert((PrevTSK == TSK_ImplicitInstantiation ||
9411 PrevPointOfInstantiation.isValid()) &&
9412 "Explicit instantiation without point of instantiation?");
9413
9414 // C++ [temp.expl.spec]p6:
9415 // If a template, a member template or the member of a class template
9416 // is explicitly specialized then that specialization shall be declared
9417 // before the first use of that specialization that would cause an
9418 // implicit instantiation to take place, in every translation unit in
9419 // which such a use occurs; no diagnostic is required.
9420 for (Decl *Prev = PrevDecl; Prev; Prev = Prev->getPreviousDecl()) {
9421 // Is there any previous explicit specialization declaration?
9422 if (getTemplateSpecializationKind(Prev) == TSK_ExplicitSpecialization)
9423 return false;
9424 }
9425
9426 Diag(NewLoc, diag::err_specialization_after_instantiation)
9427 << PrevDecl;
9428 Diag(PrevPointOfInstantiation, diag::note_instantiation_required_here)
9429 << (PrevTSK != TSK_ImplicitInstantiation);
9430
9431 return true;
9432 }
9433 llvm_unreachable("The switch over PrevTSK must be exhaustive.");
9434
9435 case TSK_ExplicitInstantiationDeclaration:
9436 switch (PrevTSK) {
9437 case TSK_ExplicitInstantiationDeclaration:
9438 // This explicit instantiation declaration is redundant (that's okay).
9439 HasNoEffect = true;
9440 return false;
9441
9442 case TSK_Undeclared:
9443 case TSK_ImplicitInstantiation:
9444 // We're explicitly instantiating something that may have already been
9445 // implicitly instantiated; that's fine.
9446 return false;
9447
9448 case TSK_ExplicitSpecialization:
9449 // C++0x [temp.explicit]p4:
9450 // For a given set of template parameters, if an explicit instantiation
9451 // of a template appears after a declaration of an explicit
9452 // specialization for that template, the explicit instantiation has no
9453 // effect.
9454 HasNoEffect = true;
9455 return false;
9456
9457 case TSK_ExplicitInstantiationDefinition:
9458 // C++0x [temp.explicit]p10:
9459 // If an entity is the subject of both an explicit instantiation
9460 // declaration and an explicit instantiation definition in the same
9461 // translation unit, the definition shall follow the declaration.
9462 Diag(NewLoc,
9463 diag::err_explicit_instantiation_declaration_after_definition);
9464
9465 // Explicit instantiations following a specialization have no effect and
9466 // hence no PrevPointOfInstantiation. In that case, walk decl backwards
9467 // until a valid name loc is found.
9468 Diag(DiagLocForExplicitInstantiation(PrevDecl, PrevPointOfInstantiation),
9469 diag::note_explicit_instantiation_definition_here);
9470 HasNoEffect = true;
9471 return false;
9472 }
9473 llvm_unreachable("Unexpected TemplateSpecializationKind!");
9474
9475 case TSK_ExplicitInstantiationDefinition:
9476 switch (PrevTSK) {
9477 case TSK_Undeclared:
9478 case TSK_ImplicitInstantiation:
9479 // We're explicitly instantiating something that may have already been
9480 // implicitly instantiated; that's fine.
9481 return false;
9482
9483 case TSK_ExplicitSpecialization:
9484 // C++ DR 259, C++0x [temp.explicit]p4:
9485 // For a given set of template parameters, if an explicit
9486 // instantiation of a template appears after a declaration of
9487 // an explicit specialization for that template, the explicit
9488 // instantiation has no effect.
9489 Diag(NewLoc, diag::warn_explicit_instantiation_after_specialization)
9490 << PrevDecl;
9491 Diag(PrevDecl->getLocation(),
9492 diag::note_previous_template_specialization);
9493 HasNoEffect = true;
9494 return false;
9495
9496 case TSK_ExplicitInstantiationDeclaration:
9497 // We're explicitly instantiating a definition for something for which we
9498 // were previously asked to suppress instantiations. That's fine.
9499
9500 // C++0x [temp.explicit]p4:
9501 // For a given set of template parameters, if an explicit instantiation
9502 // of a template appears after a declaration of an explicit
9503 // specialization for that template, the explicit instantiation has no
9504 // effect.
9505 for (Decl *Prev = PrevDecl; Prev; Prev = Prev->getPreviousDecl()) {
9506 // Is there any previous explicit specialization declaration?
9507 if (getTemplateSpecializationKind(Prev) == TSK_ExplicitSpecialization) {
9508 HasNoEffect = true;
9509 break;
9510 }
9511 }
9512
9513 return false;
9514
9515 case TSK_ExplicitInstantiationDefinition:
9516 // C++0x [temp.spec]p5:
9517 // For a given template and a given set of template-arguments,
9518 // - an explicit instantiation definition shall appear at most once
9519 // in a program,
9520
9521 // MSVCCompat: MSVC silently ignores duplicate explicit instantiations.
9522 Diag(NewLoc, (getLangOpts().MSVCCompat)
9523 ? diag::ext_explicit_instantiation_duplicate
9524 : diag::err_explicit_instantiation_duplicate)
9525 << PrevDecl;
9526 Diag(DiagLocForExplicitInstantiation(PrevDecl, PrevPointOfInstantiation),
9527 diag::note_previous_explicit_instantiation);
9528 HasNoEffect = true;
9529 return false;
9530 }
9531 }
9532
9533 llvm_unreachable("Missing specialization/instantiation case?");
9534 }
9535
9536 /// Perform semantic analysis for the given dependent function
9537 /// template specialization.
9538 ///
9539 /// The only possible way to get a dependent function template specialization
9540 /// is with a friend declaration, like so:
9541 ///
9542 /// \code
9543 /// template \<class T> void foo(T);
9544 /// template \<class T> class A {
9545 /// friend void foo<>(T);
9546 /// };
9547 /// \endcode
9548 ///
9549 /// There really isn't any useful analysis we can do here, so we
9550 /// just store the information.
CheckDependentFunctionTemplateSpecialization(FunctionDecl * FD,const TemplateArgumentListInfo * ExplicitTemplateArgs,LookupResult & Previous)9551 bool Sema::CheckDependentFunctionTemplateSpecialization(
9552 FunctionDecl *FD, const TemplateArgumentListInfo *ExplicitTemplateArgs,
9553 LookupResult &Previous) {
9554 // Remove anything from Previous that isn't a function template in
9555 // the correct context.
9556 DeclContext *FDLookupContext = FD->getDeclContext()->getRedeclContext();
9557 LookupResult::Filter F = Previous.makeFilter();
9558 enum DiscardReason { NotAFunctionTemplate, NotAMemberOfEnclosing };
9559 SmallVector<std::pair<DiscardReason, Decl *>, 8> DiscardedCandidates;
9560 while (F.hasNext()) {
9561 NamedDecl *D = F.next()->getUnderlyingDecl();
9562 if (!isa<FunctionTemplateDecl>(D)) {
9563 F.erase();
9564 DiscardedCandidates.push_back(std::make_pair(NotAFunctionTemplate, D));
9565 continue;
9566 }
9567
9568 if (!FDLookupContext->InEnclosingNamespaceSetOf(
9569 D->getDeclContext()->getRedeclContext())) {
9570 F.erase();
9571 DiscardedCandidates.push_back(std::make_pair(NotAMemberOfEnclosing, D));
9572 continue;
9573 }
9574 }
9575 F.done();
9576
9577 bool IsFriend = FD->getFriendObjectKind() != Decl::FOK_None;
9578 if (Previous.empty()) {
9579 Diag(FD->getLocation(), diag::err_dependent_function_template_spec_no_match)
9580 << IsFriend;
9581 for (auto &P : DiscardedCandidates)
9582 Diag(P.second->getLocation(),
9583 diag::note_dependent_function_template_spec_discard_reason)
9584 << P.first << IsFriend;
9585 return true;
9586 }
9587
9588 FD->setDependentTemplateSpecialization(Context, Previous.asUnresolvedSet(),
9589 ExplicitTemplateArgs);
9590 return false;
9591 }
9592
9593 /// Perform semantic analysis for the given function template
9594 /// specialization.
9595 ///
9596 /// This routine performs all of the semantic analysis required for an
9597 /// explicit function template specialization. On successful completion,
9598 /// the function declaration \p FD will become a function template
9599 /// specialization.
9600 ///
9601 /// \param FD the function declaration, which will be updated to become a
9602 /// function template specialization.
9603 ///
9604 /// \param ExplicitTemplateArgs the explicitly-provided template arguments,
9605 /// if any. Note that this may be valid info even when 0 arguments are
9606 /// explicitly provided as in, e.g., \c void sort<>(char*, char*);
9607 /// as it anyway contains info on the angle brackets locations.
9608 ///
9609 /// \param Previous the set of declarations that may be specialized by
9610 /// this function specialization.
9611 ///
9612 /// \param QualifiedFriend whether this is a lookup for a qualified friend
9613 /// declaration with no explicit template argument list that might be
9614 /// befriending a function template specialization.
CheckFunctionTemplateSpecialization(FunctionDecl * FD,TemplateArgumentListInfo * ExplicitTemplateArgs,LookupResult & Previous,bool QualifiedFriend)9615 bool Sema::CheckFunctionTemplateSpecialization(
9616 FunctionDecl *FD, TemplateArgumentListInfo *ExplicitTemplateArgs,
9617 LookupResult &Previous, bool QualifiedFriend) {
9618 // The set of function template specializations that could match this
9619 // explicit function template specialization.
9620 UnresolvedSet<8> Candidates;
9621 TemplateSpecCandidateSet FailedCandidates(FD->getLocation(),
9622 /*ForTakingAddress=*/false);
9623
9624 llvm::SmallDenseMap<FunctionDecl *, TemplateArgumentListInfo, 8>
9625 ConvertedTemplateArgs;
9626
9627 DeclContext *FDLookupContext = FD->getDeclContext()->getRedeclContext();
9628 for (LookupResult::iterator I = Previous.begin(), E = Previous.end();
9629 I != E; ++I) {
9630 NamedDecl *Ovl = (*I)->getUnderlyingDecl();
9631 if (FunctionTemplateDecl *FunTmpl = dyn_cast<FunctionTemplateDecl>(Ovl)) {
9632 // Only consider templates found within the same semantic lookup scope as
9633 // FD.
9634 if (!FDLookupContext->InEnclosingNamespaceSetOf(
9635 Ovl->getDeclContext()->getRedeclContext()))
9636 continue;
9637
9638 // When matching a constexpr member function template specialization
9639 // against the primary template, we don't yet know whether the
9640 // specialization has an implicit 'const' (because we don't know whether
9641 // it will be a static member function until we know which template it
9642 // specializes), so adjust it now assuming it specializes this template.
9643 QualType FT = FD->getType();
9644 if (FD->isConstexpr()) {
9645 CXXMethodDecl *OldMD =
9646 dyn_cast<CXXMethodDecl>(FunTmpl->getTemplatedDecl());
9647 if (OldMD && OldMD->isConst()) {
9648 const FunctionProtoType *FPT = FT->castAs<FunctionProtoType>();
9649 FunctionProtoType::ExtProtoInfo EPI = FPT->getExtProtoInfo();
9650 EPI.TypeQuals.addConst();
9651 FT = Context.getFunctionType(FPT->getReturnType(),
9652 FPT->getParamTypes(), EPI);
9653 }
9654 }
9655
9656 TemplateArgumentListInfo Args;
9657 if (ExplicitTemplateArgs)
9658 Args = *ExplicitTemplateArgs;
9659
9660 // C++ [temp.expl.spec]p11:
9661 // A trailing template-argument can be left unspecified in the
9662 // template-id naming an explicit function template specialization
9663 // provided it can be deduced from the function argument type.
9664 // Perform template argument deduction to determine whether we may be
9665 // specializing this template.
9666 // FIXME: It is somewhat wasteful to build
9667 TemplateDeductionInfo Info(FailedCandidates.getLocation());
9668 FunctionDecl *Specialization = nullptr;
9669 if (TemplateDeductionResult TDK = DeduceTemplateArguments(
9670 cast<FunctionTemplateDecl>(FunTmpl->getFirstDecl()),
9671 ExplicitTemplateArgs ? &Args : nullptr, FT, Specialization,
9672 Info)) {
9673 // Template argument deduction failed; record why it failed, so
9674 // that we can provide nifty diagnostics.
9675 FailedCandidates.addCandidate().set(
9676 I.getPair(), FunTmpl->getTemplatedDecl(),
9677 MakeDeductionFailureInfo(Context, TDK, Info));
9678 (void)TDK;
9679 continue;
9680 }
9681
9682 // Target attributes are part of the cuda function signature, so
9683 // the deduced template's cuda target must match that of the
9684 // specialization. Given that C++ template deduction does not
9685 // take target attributes into account, we reject candidates
9686 // here that have a different target.
9687 if (LangOpts.CUDA &&
9688 IdentifyCUDATarget(Specialization,
9689 /* IgnoreImplicitHDAttr = */ true) !=
9690 IdentifyCUDATarget(FD, /* IgnoreImplicitHDAttr = */ true)) {
9691 FailedCandidates.addCandidate().set(
9692 I.getPair(), FunTmpl->getTemplatedDecl(),
9693 MakeDeductionFailureInfo(Context, TDK_CUDATargetMismatch, Info));
9694 continue;
9695 }
9696
9697 // Record this candidate.
9698 if (ExplicitTemplateArgs)
9699 ConvertedTemplateArgs[Specialization] = std::move(Args);
9700 Candidates.addDecl(Specialization, I.getAccess());
9701 }
9702 }
9703
9704 // For a qualified friend declaration (with no explicit marker to indicate
9705 // that a template specialization was intended), note all (template and
9706 // non-template) candidates.
9707 if (QualifiedFriend && Candidates.empty()) {
9708 Diag(FD->getLocation(), diag::err_qualified_friend_no_match)
9709 << FD->getDeclName() << FDLookupContext;
9710 // FIXME: We should form a single candidate list and diagnose all
9711 // candidates at once, to get proper sorting and limiting.
9712 for (auto *OldND : Previous) {
9713 if (auto *OldFD = dyn_cast<FunctionDecl>(OldND->getUnderlyingDecl()))
9714 NoteOverloadCandidate(OldND, OldFD, CRK_None, FD->getType(), false);
9715 }
9716 FailedCandidates.NoteCandidates(*this, FD->getLocation());
9717 return true;
9718 }
9719
9720 // Find the most specialized function template.
9721 UnresolvedSetIterator Result = getMostSpecialized(
9722 Candidates.begin(), Candidates.end(), FailedCandidates, FD->getLocation(),
9723 PDiag(diag::err_function_template_spec_no_match) << FD->getDeclName(),
9724 PDiag(diag::err_function_template_spec_ambiguous)
9725 << FD->getDeclName() << (ExplicitTemplateArgs != nullptr),
9726 PDiag(diag::note_function_template_spec_matched));
9727
9728 if (Result == Candidates.end())
9729 return true;
9730
9731 // Ignore access information; it doesn't figure into redeclaration checking.
9732 FunctionDecl *Specialization = cast<FunctionDecl>(*Result);
9733
9734 FunctionTemplateSpecializationInfo *SpecInfo
9735 = Specialization->getTemplateSpecializationInfo();
9736 assert(SpecInfo && "Function template specialization info missing?");
9737
9738 // Note: do not overwrite location info if previous template
9739 // specialization kind was explicit.
9740 TemplateSpecializationKind TSK = SpecInfo->getTemplateSpecializationKind();
9741 if (TSK == TSK_Undeclared || TSK == TSK_ImplicitInstantiation) {
9742 Specialization->setLocation(FD->getLocation());
9743 Specialization->setLexicalDeclContext(FD->getLexicalDeclContext());
9744 // C++11 [dcl.constexpr]p1: An explicit specialization of a constexpr
9745 // function can differ from the template declaration with respect to
9746 // the constexpr specifier.
9747 // FIXME: We need an update record for this AST mutation.
9748 // FIXME: What if there are multiple such prior declarations (for instance,
9749 // from different modules)?
9750 Specialization->setConstexprKind(FD->getConstexprKind());
9751 }
9752
9753 // FIXME: Check if the prior specialization has a point of instantiation.
9754 // If so, we have run afoul of .
9755
9756 // If this is a friend declaration, then we're not really declaring
9757 // an explicit specialization.
9758 bool isFriend = (FD->getFriendObjectKind() != Decl::FOK_None);
9759
9760 // Check the scope of this explicit specialization.
9761 if (!isFriend &&
9762 CheckTemplateSpecializationScope(*this,
9763 Specialization->getPrimaryTemplate(),
9764 Specialization, FD->getLocation(),
9765 false))
9766 return true;
9767
9768 // C++ [temp.expl.spec]p6:
9769 // If a template, a member template or the member of a class template is
9770 // explicitly specialized then that specialization shall be declared
9771 // before the first use of that specialization that would cause an implicit
9772 // instantiation to take place, in every translation unit in which such a
9773 // use occurs; no diagnostic is required.
9774 bool HasNoEffect = false;
9775 if (!isFriend &&
9776 CheckSpecializationInstantiationRedecl(FD->getLocation(),
9777 TSK_ExplicitSpecialization,
9778 Specialization,
9779 SpecInfo->getTemplateSpecializationKind(),
9780 SpecInfo->getPointOfInstantiation(),
9781 HasNoEffect))
9782 return true;
9783
9784 // Mark the prior declaration as an explicit specialization, so that later
9785 // clients know that this is an explicit specialization.
9786 if (!isFriend) {
9787 // Since explicit specializations do not inherit '=delete' from their
9788 // primary function template - check if the 'specialization' that was
9789 // implicitly generated (during template argument deduction for partial
9790 // ordering) from the most specialized of all the function templates that
9791 // 'FD' could have been specializing, has a 'deleted' definition. If so,
9792 // first check that it was implicitly generated during template argument
9793 // deduction by making sure it wasn't referenced, and then reset the deleted
9794 // flag to not-deleted, so that we can inherit that information from 'FD'.
9795 if (Specialization->isDeleted() && !SpecInfo->isExplicitSpecialization() &&
9796 !Specialization->getCanonicalDecl()->isReferenced()) {
9797 // FIXME: This assert will not hold in the presence of modules.
9798 assert(
9799 Specialization->getCanonicalDecl() == Specialization &&
9800 "This must be the only existing declaration of this specialization");
9801 // FIXME: We need an update record for this AST mutation.
9802 Specialization->setDeletedAsWritten(false);
9803 }
9804 // FIXME: We need an update record for this AST mutation.
9805 SpecInfo->setTemplateSpecializationKind(TSK_ExplicitSpecialization);
9806 MarkUnusedFileScopedDecl(Specialization);
9807 }
9808
9809 // Turn the given function declaration into a function template
9810 // specialization, with the template arguments from the previous
9811 // specialization.
9812 // Take copies of (semantic and syntactic) template argument lists.
9813 const TemplateArgumentList* TemplArgs = new (Context)
9814 TemplateArgumentList(Specialization->getTemplateSpecializationArgs());
9815 FD->setFunctionTemplateSpecialization(
9816 Specialization->getPrimaryTemplate(), TemplArgs, /*InsertPos=*/nullptr,
9817 SpecInfo->getTemplateSpecializationKind(),
9818 ExplicitTemplateArgs ? &ConvertedTemplateArgs[Specialization] : nullptr);
9819
9820 // A function template specialization inherits the target attributes
9821 // of its template. (We require the attributes explicitly in the
9822 // code to match, but a template may have implicit attributes by
9823 // virtue e.g. of being constexpr, and it passes these implicit
9824 // attributes on to its specializations.)
9825 if (LangOpts.CUDA)
9826 inheritCUDATargetAttrs(FD, *Specialization->getPrimaryTemplate());
9827
9828 // The "previous declaration" for this function template specialization is
9829 // the prior function template specialization.
9830 Previous.clear();
9831 Previous.addDecl(Specialization);
9832 return false;
9833 }
9834
9835 /// Perform semantic analysis for the given non-template member
9836 /// specialization.
9837 ///
9838 /// This routine performs all of the semantic analysis required for an
9839 /// explicit member function specialization. On successful completion,
9840 /// the function declaration \p FD will become a member function
9841 /// specialization.
9842 ///
9843 /// \param Member the member declaration, which will be updated to become a
9844 /// specialization.
9845 ///
9846 /// \param Previous the set of declarations, one of which may be specialized
9847 /// by this function specialization; the set will be modified to contain the
9848 /// redeclared member.
9849 bool
CheckMemberSpecialization(NamedDecl * Member,LookupResult & Previous)9850 Sema::CheckMemberSpecialization(NamedDecl *Member, LookupResult &Previous) {
9851 assert(!isa<TemplateDecl>(Member) && "Only for non-template members");
9852
9853 // Try to find the member we are instantiating.
9854 NamedDecl *FoundInstantiation = nullptr;
9855 NamedDecl *Instantiation = nullptr;
9856 NamedDecl *InstantiatedFrom = nullptr;
9857 MemberSpecializationInfo *MSInfo = nullptr;
9858
9859 if (Previous.empty()) {
9860 // Nowhere to look anyway.
9861 } else if (FunctionDecl *Function = dyn_cast<FunctionDecl>(Member)) {
9862 for (LookupResult::iterator I = Previous.begin(), E = Previous.end();
9863 I != E; ++I) {
9864 NamedDecl *D = (*I)->getUnderlyingDecl();
9865 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(D)) {
9866 QualType Adjusted = Function->getType();
9867 if (!hasExplicitCallingConv(Adjusted))
9868 Adjusted = adjustCCAndNoReturn(Adjusted, Method->getType());
9869 // This doesn't handle deduced return types, but both function
9870 // declarations should be undeduced at this point.
9871 if (Context.hasSameType(Adjusted, Method->getType())) {
9872 FoundInstantiation = *I;
9873 Instantiation = Method;
9874 InstantiatedFrom = Method->getInstantiatedFromMemberFunction();
9875 MSInfo = Method->getMemberSpecializationInfo();
9876 break;
9877 }
9878 }
9879 }
9880 } else if (isa<VarDecl>(Member)) {
9881 VarDecl *PrevVar;
9882 if (Previous.isSingleResult() &&
9883 (PrevVar = dyn_cast<VarDecl>(Previous.getFoundDecl())))
9884 if (PrevVar->isStaticDataMember()) {
9885 FoundInstantiation = Previous.getRepresentativeDecl();
9886 Instantiation = PrevVar;
9887 InstantiatedFrom = PrevVar->getInstantiatedFromStaticDataMember();
9888 MSInfo = PrevVar->getMemberSpecializationInfo();
9889 }
9890 } else if (isa<RecordDecl>(Member)) {
9891 CXXRecordDecl *PrevRecord;
9892 if (Previous.isSingleResult() &&
9893 (PrevRecord = dyn_cast<CXXRecordDecl>(Previous.getFoundDecl()))) {
9894 FoundInstantiation = Previous.getRepresentativeDecl();
9895 Instantiation = PrevRecord;
9896 InstantiatedFrom = PrevRecord->getInstantiatedFromMemberClass();
9897 MSInfo = PrevRecord->getMemberSpecializationInfo();
9898 }
9899 } else if (isa<EnumDecl>(Member)) {
9900 EnumDecl *PrevEnum;
9901 if (Previous.isSingleResult() &&
9902 (PrevEnum = dyn_cast<EnumDecl>(Previous.getFoundDecl()))) {
9903 FoundInstantiation = Previous.getRepresentativeDecl();
9904 Instantiation = PrevEnum;
9905 InstantiatedFrom = PrevEnum->getInstantiatedFromMemberEnum();
9906 MSInfo = PrevEnum->getMemberSpecializationInfo();
9907 }
9908 }
9909
9910 if (!Instantiation) {
9911 // There is no previous declaration that matches. Since member
9912 // specializations are always out-of-line, the caller will complain about
9913 // this mismatch later.
9914 return false;
9915 }
9916
9917 // A member specialization in a friend declaration isn't really declaring
9918 // an explicit specialization, just identifying a specific (possibly implicit)
9919 // specialization. Don't change the template specialization kind.
9920 //
9921 // FIXME: Is this really valid? Other compilers reject.
9922 if (Member->getFriendObjectKind() != Decl::FOK_None) {
9923 // Preserve instantiation information.
9924 if (InstantiatedFrom && isa<CXXMethodDecl>(Member)) {
9925 cast<CXXMethodDecl>(Member)->setInstantiationOfMemberFunction(
9926 cast<CXXMethodDecl>(InstantiatedFrom),
9927 cast<CXXMethodDecl>(Instantiation)->getTemplateSpecializationKind());
9928 } else if (InstantiatedFrom && isa<CXXRecordDecl>(Member)) {
9929 cast<CXXRecordDecl>(Member)->setInstantiationOfMemberClass(
9930 cast<CXXRecordDecl>(InstantiatedFrom),
9931 cast<CXXRecordDecl>(Instantiation)->getTemplateSpecializationKind());
9932 }
9933
9934 Previous.clear();
9935 Previous.addDecl(FoundInstantiation);
9936 return false;
9937 }
9938
9939 // Make sure that this is a specialization of a member.
9940 if (!InstantiatedFrom) {
9941 Diag(Member->getLocation(), diag::err_spec_member_not_instantiated)
9942 << Member;
9943 Diag(Instantiation->getLocation(), diag::note_specialized_decl);
9944 return true;
9945 }
9946
9947 // C++ [temp.expl.spec]p6:
9948 // If a template, a member template or the member of a class template is
9949 // explicitly specialized then that specialization shall be declared
9950 // before the first use of that specialization that would cause an implicit
9951 // instantiation to take place, in every translation unit in which such a
9952 // use occurs; no diagnostic is required.
9953 assert(MSInfo && "Member specialization info missing?");
9954
9955 bool HasNoEffect = false;
9956 if (CheckSpecializationInstantiationRedecl(Member->getLocation(),
9957 TSK_ExplicitSpecialization,
9958 Instantiation,
9959 MSInfo->getTemplateSpecializationKind(),
9960 MSInfo->getPointOfInstantiation(),
9961 HasNoEffect))
9962 return true;
9963
9964 // Check the scope of this explicit specialization.
9965 if (CheckTemplateSpecializationScope(*this,
9966 InstantiatedFrom,
9967 Instantiation, Member->getLocation(),
9968 false))
9969 return true;
9970
9971 // Note that this member specialization is an "instantiation of" the
9972 // corresponding member of the original template.
9973 if (auto *MemberFunction = dyn_cast<FunctionDecl>(Member)) {
9974 FunctionDecl *InstantiationFunction = cast<FunctionDecl>(Instantiation);
9975 if (InstantiationFunction->getTemplateSpecializationKind() ==
9976 TSK_ImplicitInstantiation) {
9977 // Explicit specializations of member functions of class templates do not
9978 // inherit '=delete' from the member function they are specializing.
9979 if (InstantiationFunction->isDeleted()) {
9980 // FIXME: This assert will not hold in the presence of modules.
9981 assert(InstantiationFunction->getCanonicalDecl() ==
9982 InstantiationFunction);
9983 // FIXME: We need an update record for this AST mutation.
9984 InstantiationFunction->setDeletedAsWritten(false);
9985 }
9986 }
9987
9988 MemberFunction->setInstantiationOfMemberFunction(
9989 cast<CXXMethodDecl>(InstantiatedFrom), TSK_ExplicitSpecialization);
9990 } else if (auto *MemberVar = dyn_cast<VarDecl>(Member)) {
9991 MemberVar->setInstantiationOfStaticDataMember(
9992 cast<VarDecl>(InstantiatedFrom), TSK_ExplicitSpecialization);
9993 } else if (auto *MemberClass = dyn_cast<CXXRecordDecl>(Member)) {
9994 MemberClass->setInstantiationOfMemberClass(
9995 cast<CXXRecordDecl>(InstantiatedFrom), TSK_ExplicitSpecialization);
9996 } else if (auto *MemberEnum = dyn_cast<EnumDecl>(Member)) {
9997 MemberEnum->setInstantiationOfMemberEnum(
9998 cast<EnumDecl>(InstantiatedFrom), TSK_ExplicitSpecialization);
9999 } else {
10000 llvm_unreachable("unknown member specialization kind");
10001 }
10002
10003 // Save the caller the trouble of having to figure out which declaration
10004 // this specialization matches.
10005 Previous.clear();
10006 Previous.addDecl(FoundInstantiation);
10007 return false;
10008 }
10009
10010 /// Complete the explicit specialization of a member of a class template by
10011 /// updating the instantiated member to be marked as an explicit specialization.
10012 ///
10013 /// \param OrigD The member declaration instantiated from the template.
10014 /// \param Loc The location of the explicit specialization of the member.
10015 template<typename DeclT>
completeMemberSpecializationImpl(Sema & S,DeclT * OrigD,SourceLocation Loc)10016 static void completeMemberSpecializationImpl(Sema &S, DeclT *OrigD,
10017 SourceLocation Loc) {
10018 if (OrigD->getTemplateSpecializationKind() != TSK_ImplicitInstantiation)
10019 return;
10020
10021 // FIXME: Inform AST mutation listeners of this AST mutation.
10022 // FIXME: If there are multiple in-class declarations of the member (from
10023 // multiple modules, or a declaration and later definition of a member type),
10024 // should we update all of them?
10025 OrigD->setTemplateSpecializationKind(TSK_ExplicitSpecialization);
10026 OrigD->setLocation(Loc);
10027 }
10028
CompleteMemberSpecialization(NamedDecl * Member,LookupResult & Previous)10029 void Sema::CompleteMemberSpecialization(NamedDecl *Member,
10030 LookupResult &Previous) {
10031 NamedDecl *Instantiation = cast<NamedDecl>(Member->getCanonicalDecl());
10032 if (Instantiation == Member)
10033 return;
10034
10035 if (auto *Function = dyn_cast<CXXMethodDecl>(Instantiation))
10036 completeMemberSpecializationImpl(*this, Function, Member->getLocation());
10037 else if (auto *Var = dyn_cast<VarDecl>(Instantiation))
10038 completeMemberSpecializationImpl(*this, Var, Member->getLocation());
10039 else if (auto *Record = dyn_cast<CXXRecordDecl>(Instantiation))
10040 completeMemberSpecializationImpl(*this, Record, Member->getLocation());
10041 else if (auto *Enum = dyn_cast<EnumDecl>(Instantiation))
10042 completeMemberSpecializationImpl(*this, Enum, Member->getLocation());
10043 else
10044 llvm_unreachable("unknown member specialization kind");
10045 }
10046
10047 /// Check the scope of an explicit instantiation.
10048 ///
10049 /// \returns true if a serious error occurs, false otherwise.
CheckExplicitInstantiationScope(Sema & S,NamedDecl * D,SourceLocation InstLoc,bool WasQualifiedName)10050 static bool CheckExplicitInstantiationScope(Sema &S, NamedDecl *D,
10051 SourceLocation InstLoc,
10052 bool WasQualifiedName) {
10053 DeclContext *OrigContext= D->getDeclContext()->getEnclosingNamespaceContext();
10054 DeclContext *CurContext = S.CurContext->getRedeclContext();
10055
10056 if (CurContext->isRecord()) {
10057 S.Diag(InstLoc, diag::err_explicit_instantiation_in_class)
10058 << D;
10059 return true;
10060 }
10061
10062 // C++11 [temp.explicit]p3:
10063 // An explicit instantiation shall appear in an enclosing namespace of its
10064 // template. If the name declared in the explicit instantiation is an
10065 // unqualified name, the explicit instantiation shall appear in the
10066 // namespace where its template is declared or, if that namespace is inline
10067 // (7.3.1), any namespace from its enclosing namespace set.
10068 //
10069 // This is DR275, which we do not retroactively apply to C++98/03.
10070 if (WasQualifiedName) {
10071 if (CurContext->Encloses(OrigContext))
10072 return false;
10073 } else {
10074 if (CurContext->InEnclosingNamespaceSetOf(OrigContext))
10075 return false;
10076 }
10077
10078 if (NamespaceDecl *NS = dyn_cast<NamespaceDecl>(OrigContext)) {
10079 if (WasQualifiedName)
10080 S.Diag(InstLoc,
10081 S.getLangOpts().CPlusPlus11?
10082 diag::err_explicit_instantiation_out_of_scope :
10083 diag::warn_explicit_instantiation_out_of_scope_0x)
10084 << D << NS;
10085 else
10086 S.Diag(InstLoc,
10087 S.getLangOpts().CPlusPlus11?
10088 diag::err_explicit_instantiation_unqualified_wrong_namespace :
10089 diag::warn_explicit_instantiation_unqualified_wrong_namespace_0x)
10090 << D << NS;
10091 } else
10092 S.Diag(InstLoc,
10093 S.getLangOpts().CPlusPlus11?
10094 diag::err_explicit_instantiation_must_be_global :
10095 diag::warn_explicit_instantiation_must_be_global_0x)
10096 << D;
10097 S.Diag(D->getLocation(), diag::note_explicit_instantiation_here);
10098 return false;
10099 }
10100
10101 /// Common checks for whether an explicit instantiation of \p D is valid.
CheckExplicitInstantiation(Sema & S,NamedDecl * D,SourceLocation InstLoc,bool WasQualifiedName,TemplateSpecializationKind TSK)10102 static bool CheckExplicitInstantiation(Sema &S, NamedDecl *D,
10103 SourceLocation InstLoc,
10104 bool WasQualifiedName,
10105 TemplateSpecializationKind TSK) {
10106 // C++ [temp.explicit]p13:
10107 // An explicit instantiation declaration shall not name a specialization of
10108 // a template with internal linkage.
10109 if (TSK == TSK_ExplicitInstantiationDeclaration &&
10110 D->getFormalLinkage() == Linkage::Internal) {
10111 S.Diag(InstLoc, diag::err_explicit_instantiation_internal_linkage) << D;
10112 return true;
10113 }
10114
10115 // C++11 [temp.explicit]p3: [DR 275]
10116 // An explicit instantiation shall appear in an enclosing namespace of its
10117 // template.
10118 if (CheckExplicitInstantiationScope(S, D, InstLoc, WasQualifiedName))
10119 return true;
10120
10121 return false;
10122 }
10123
10124 /// Determine whether the given scope specifier has a template-id in it.
ScopeSpecifierHasTemplateId(const CXXScopeSpec & SS)10125 static bool ScopeSpecifierHasTemplateId(const CXXScopeSpec &SS) {
10126 if (!SS.isSet())
10127 return false;
10128
10129 // C++11 [temp.explicit]p3:
10130 // If the explicit instantiation is for a member function, a member class
10131 // or a static data member of a class template specialization, the name of
10132 // the class template specialization in the qualified-id for the member
10133 // name shall be a simple-template-id.
10134 //
10135 // C++98 has the same restriction, just worded differently.
10136 for (NestedNameSpecifier *NNS = SS.getScopeRep(); NNS;
10137 NNS = NNS->getPrefix())
10138 if (const Type *T = NNS->getAsType())
10139 if (isa<TemplateSpecializationType>(T))
10140 return true;
10141
10142 return false;
10143 }
10144
10145 /// Make a dllexport or dllimport attr on a class template specialization take
10146 /// effect.
dllExportImportClassTemplateSpecialization(Sema & S,ClassTemplateSpecializationDecl * Def)10147 static void dllExportImportClassTemplateSpecialization(
10148 Sema &S, ClassTemplateSpecializationDecl *Def) {
10149 auto *A = cast_or_null<InheritableAttr>(getDLLAttr(Def));
10150 assert(A && "dllExportImportClassTemplateSpecialization called "
10151 "on Def without dllexport or dllimport");
10152
10153 // We reject explicit instantiations in class scope, so there should
10154 // never be any delayed exported classes to worry about.
10155 assert(S.DelayedDllExportClasses.empty() &&
10156 "delayed exports present at explicit instantiation");
10157 S.checkClassLevelDLLAttribute(Def);
10158
10159 // Propagate attribute to base class templates.
10160 for (auto &B : Def->bases()) {
10161 if (auto *BT = dyn_cast_or_null<ClassTemplateSpecializationDecl>(
10162 B.getType()->getAsCXXRecordDecl()))
10163 S.propagateDLLAttrToBaseClassTemplate(Def, A, BT, B.getBeginLoc());
10164 }
10165
10166 S.referenceDLLExportedClassMethods();
10167 }
10168
10169 // Explicit instantiation of a class template specialization
ActOnExplicitInstantiation(Scope * S,SourceLocation ExternLoc,SourceLocation TemplateLoc,unsigned TagSpec,SourceLocation KWLoc,const CXXScopeSpec & SS,TemplateTy TemplateD,SourceLocation TemplateNameLoc,SourceLocation LAngleLoc,ASTTemplateArgsPtr TemplateArgsIn,SourceLocation RAngleLoc,const ParsedAttributesView & Attr)10170 DeclResult Sema::ActOnExplicitInstantiation(
10171 Scope *S, SourceLocation ExternLoc, SourceLocation TemplateLoc,
10172 unsigned TagSpec, SourceLocation KWLoc, const CXXScopeSpec &SS,
10173 TemplateTy TemplateD, SourceLocation TemplateNameLoc,
10174 SourceLocation LAngleLoc, ASTTemplateArgsPtr TemplateArgsIn,
10175 SourceLocation RAngleLoc, const ParsedAttributesView &Attr) {
10176 // Find the class template we're specializing
10177 TemplateName Name = TemplateD.get();
10178 TemplateDecl *TD = Name.getAsTemplateDecl();
10179 // Check that the specialization uses the same tag kind as the
10180 // original template.
10181 TagTypeKind Kind = TypeWithKeyword::getTagTypeKindForTypeSpec(TagSpec);
10182 assert(Kind != TagTypeKind::Enum &&
10183 "Invalid enum tag in class template explicit instantiation!");
10184
10185 ClassTemplateDecl *ClassTemplate = dyn_cast<ClassTemplateDecl>(TD);
10186
10187 if (!ClassTemplate) {
10188 NonTagKind NTK = getNonTagTypeDeclKind(TD, Kind);
10189 Diag(TemplateNameLoc, diag::err_tag_reference_non_tag)
10190 << TD << NTK << llvm::to_underlying(Kind);
10191 Diag(TD->getLocation(), diag::note_previous_use);
10192 return true;
10193 }
10194
10195 if (!isAcceptableTagRedeclaration(ClassTemplate->getTemplatedDecl(),
10196 Kind, /*isDefinition*/false, KWLoc,
10197 ClassTemplate->getIdentifier())) {
10198 Diag(KWLoc, diag::err_use_with_wrong_tag)
10199 << ClassTemplate
10200 << FixItHint::CreateReplacement(KWLoc,
10201 ClassTemplate->getTemplatedDecl()->getKindName());
10202 Diag(ClassTemplate->getTemplatedDecl()->getLocation(),
10203 diag::note_previous_use);
10204 Kind = ClassTemplate->getTemplatedDecl()->getTagKind();
10205 }
10206
10207 // C++0x [temp.explicit]p2:
10208 // There are two forms of explicit instantiation: an explicit instantiation
10209 // definition and an explicit instantiation declaration. An explicit
10210 // instantiation declaration begins with the extern keyword. [...]
10211 TemplateSpecializationKind TSK = ExternLoc.isInvalid()
10212 ? TSK_ExplicitInstantiationDefinition
10213 : TSK_ExplicitInstantiationDeclaration;
10214
10215 if (TSK == TSK_ExplicitInstantiationDeclaration &&
10216 !Context.getTargetInfo().getTriple().isWindowsGNUEnvironment()) {
10217 // Check for dllexport class template instantiation declarations,
10218 // except for MinGW mode.
10219 for (const ParsedAttr &AL : Attr) {
10220 if (AL.getKind() == ParsedAttr::AT_DLLExport) {
10221 Diag(ExternLoc,
10222 diag::warn_attribute_dllexport_explicit_instantiation_decl);
10223 Diag(AL.getLoc(), diag::note_attribute);
10224 break;
10225 }
10226 }
10227
10228 if (auto *A = ClassTemplate->getTemplatedDecl()->getAttr<DLLExportAttr>()) {
10229 Diag(ExternLoc,
10230 diag::warn_attribute_dllexport_explicit_instantiation_decl);
10231 Diag(A->getLocation(), diag::note_attribute);
10232 }
10233 }
10234
10235 // In MSVC mode, dllimported explicit instantiation definitions are treated as
10236 // instantiation declarations for most purposes.
10237 bool DLLImportExplicitInstantiationDef = false;
10238 if (TSK == TSK_ExplicitInstantiationDefinition &&
10239 Context.getTargetInfo().getCXXABI().isMicrosoft()) {
10240 // Check for dllimport class template instantiation definitions.
10241 bool DLLImport =
10242 ClassTemplate->getTemplatedDecl()->getAttr<DLLImportAttr>();
10243 for (const ParsedAttr &AL : Attr) {
10244 if (AL.getKind() == ParsedAttr::AT_DLLImport)
10245 DLLImport = true;
10246 if (AL.getKind() == ParsedAttr::AT_DLLExport) {
10247 // dllexport trumps dllimport here.
10248 DLLImport = false;
10249 break;
10250 }
10251 }
10252 if (DLLImport) {
10253 TSK = TSK_ExplicitInstantiationDeclaration;
10254 DLLImportExplicitInstantiationDef = true;
10255 }
10256 }
10257
10258 // Translate the parser's template argument list in our AST format.
10259 TemplateArgumentListInfo TemplateArgs(LAngleLoc, RAngleLoc);
10260 translateTemplateArguments(TemplateArgsIn, TemplateArgs);
10261
10262 // Check that the template argument list is well-formed for this
10263 // template.
10264 SmallVector<TemplateArgument, 4> SugaredConverted, CanonicalConverted;
10265 if (CheckTemplateArgumentList(ClassTemplate, TemplateNameLoc, TemplateArgs,
10266 false, SugaredConverted, CanonicalConverted,
10267 /*UpdateArgsWithConversions=*/true))
10268 return true;
10269
10270 // Find the class template specialization declaration that
10271 // corresponds to these arguments.
10272 void *InsertPos = nullptr;
10273 ClassTemplateSpecializationDecl *PrevDecl =
10274 ClassTemplate->findSpecialization(CanonicalConverted, InsertPos);
10275
10276 TemplateSpecializationKind PrevDecl_TSK
10277 = PrevDecl ? PrevDecl->getTemplateSpecializationKind() : TSK_Undeclared;
10278
10279 if (TSK == TSK_ExplicitInstantiationDefinition && PrevDecl != nullptr &&
10280 Context.getTargetInfo().getTriple().isWindowsGNUEnvironment()) {
10281 // Check for dllexport class template instantiation definitions in MinGW
10282 // mode, if a previous declaration of the instantiation was seen.
10283 for (const ParsedAttr &AL : Attr) {
10284 if (AL.getKind() == ParsedAttr::AT_DLLExport) {
10285 Diag(AL.getLoc(),
10286 diag::warn_attribute_dllexport_explicit_instantiation_def);
10287 break;
10288 }
10289 }
10290 }
10291
10292 if (CheckExplicitInstantiation(*this, ClassTemplate, TemplateNameLoc,
10293 SS.isSet(), TSK))
10294 return true;
10295
10296 ClassTemplateSpecializationDecl *Specialization = nullptr;
10297
10298 bool HasNoEffect = false;
10299 if (PrevDecl) {
10300 if (CheckSpecializationInstantiationRedecl(TemplateNameLoc, TSK,
10301 PrevDecl, PrevDecl_TSK,
10302 PrevDecl->getPointOfInstantiation(),
10303 HasNoEffect))
10304 return PrevDecl;
10305
10306 // Even though HasNoEffect == true means that this explicit instantiation
10307 // has no effect on semantics, we go on to put its syntax in the AST.
10308
10309 if (PrevDecl_TSK == TSK_ImplicitInstantiation ||
10310 PrevDecl_TSK == TSK_Undeclared) {
10311 // Since the only prior class template specialization with these
10312 // arguments was referenced but not declared, reuse that
10313 // declaration node as our own, updating the source location
10314 // for the template name to reflect our new declaration.
10315 // (Other source locations will be updated later.)
10316 Specialization = PrevDecl;
10317 Specialization->setLocation(TemplateNameLoc);
10318 PrevDecl = nullptr;
10319 }
10320
10321 if (PrevDecl_TSK == TSK_ExplicitInstantiationDeclaration &&
10322 DLLImportExplicitInstantiationDef) {
10323 // The new specialization might add a dllimport attribute.
10324 HasNoEffect = false;
10325 }
10326 }
10327
10328 if (!Specialization) {
10329 // Create a new class template specialization declaration node for
10330 // this explicit specialization.
10331 Specialization = ClassTemplateSpecializationDecl::Create(
10332 Context, Kind, ClassTemplate->getDeclContext(), KWLoc, TemplateNameLoc,
10333 ClassTemplate, CanonicalConverted, PrevDecl);
10334 SetNestedNameSpecifier(*this, Specialization, SS);
10335
10336 // A MSInheritanceAttr attached to the previous declaration must be
10337 // propagated to the new node prior to instantiation.
10338 if (PrevDecl) {
10339 if (const auto *A = PrevDecl->getAttr<MSInheritanceAttr>()) {
10340 auto *Clone = A->clone(getASTContext());
10341 Clone->setInherited(true);
10342 Specialization->addAttr(Clone);
10343 Consumer.AssignInheritanceModel(Specialization);
10344 }
10345 }
10346
10347 if (!HasNoEffect && !PrevDecl) {
10348 // Insert the new specialization.
10349 ClassTemplate->AddSpecialization(Specialization, InsertPos);
10350 }
10351 }
10352
10353 // Build the fully-sugared type for this explicit instantiation as
10354 // the user wrote in the explicit instantiation itself. This means
10355 // that we'll pretty-print the type retrieved from the
10356 // specialization's declaration the way that the user actually wrote
10357 // the explicit instantiation, rather than formatting the name based
10358 // on the "canonical" representation used to store the template
10359 // arguments in the specialization.
10360 TypeSourceInfo *WrittenTy
10361 = Context.getTemplateSpecializationTypeInfo(Name, TemplateNameLoc,
10362 TemplateArgs,
10363 Context.getTypeDeclType(Specialization));
10364 Specialization->setTypeAsWritten(WrittenTy);
10365
10366 // Set source locations for keywords.
10367 Specialization->setExternLoc(ExternLoc);
10368 Specialization->setTemplateKeywordLoc(TemplateLoc);
10369 Specialization->setBraceRange(SourceRange());
10370
10371 bool PreviouslyDLLExported = Specialization->hasAttr<DLLExportAttr>();
10372 ProcessDeclAttributeList(S, Specialization, Attr);
10373
10374 // Add the explicit instantiation into its lexical context. However,
10375 // since explicit instantiations are never found by name lookup, we
10376 // just put it into the declaration context directly.
10377 Specialization->setLexicalDeclContext(CurContext);
10378 CurContext->addDecl(Specialization);
10379
10380 // Syntax is now OK, so return if it has no other effect on semantics.
10381 if (HasNoEffect) {
10382 // Set the template specialization kind.
10383 Specialization->setTemplateSpecializationKind(TSK);
10384 return Specialization;
10385 }
10386
10387 // C++ [temp.explicit]p3:
10388 // A definition of a class template or class member template
10389 // shall be in scope at the point of the explicit instantiation of
10390 // the class template or class member template.
10391 //
10392 // This check comes when we actually try to perform the
10393 // instantiation.
10394 ClassTemplateSpecializationDecl *Def
10395 = cast_or_null<ClassTemplateSpecializationDecl>(
10396 Specialization->getDefinition());
10397 if (!Def)
10398 InstantiateClassTemplateSpecialization(TemplateNameLoc, Specialization, TSK);
10399 else if (TSK == TSK_ExplicitInstantiationDefinition) {
10400 MarkVTableUsed(TemplateNameLoc, Specialization, true);
10401 Specialization->setPointOfInstantiation(Def->getPointOfInstantiation());
10402 }
10403
10404 // Instantiate the members of this class template specialization.
10405 Def = cast_or_null<ClassTemplateSpecializationDecl>(
10406 Specialization->getDefinition());
10407 if (Def) {
10408 TemplateSpecializationKind Old_TSK = Def->getTemplateSpecializationKind();
10409 // Fix a TSK_ExplicitInstantiationDeclaration followed by a
10410 // TSK_ExplicitInstantiationDefinition
10411 if (Old_TSK == TSK_ExplicitInstantiationDeclaration &&
10412 (TSK == TSK_ExplicitInstantiationDefinition ||
10413 DLLImportExplicitInstantiationDef)) {
10414 // FIXME: Need to notify the ASTMutationListener that we did this.
10415 Def->setTemplateSpecializationKind(TSK);
10416
10417 if (!getDLLAttr(Def) && getDLLAttr(Specialization) &&
10418 (Context.getTargetInfo().shouldDLLImportComdatSymbols() &&
10419 !Context.getTargetInfo().getTriple().isPS())) {
10420 // An explicit instantiation definition can add a dll attribute to a
10421 // template with a previous instantiation declaration. MinGW doesn't
10422 // allow this.
10423 auto *A = cast<InheritableAttr>(
10424 getDLLAttr(Specialization)->clone(getASTContext()));
10425 A->setInherited(true);
10426 Def->addAttr(A);
10427 dllExportImportClassTemplateSpecialization(*this, Def);
10428 }
10429 }
10430
10431 // Fix a TSK_ImplicitInstantiation followed by a
10432 // TSK_ExplicitInstantiationDefinition
10433 bool NewlyDLLExported =
10434 !PreviouslyDLLExported && Specialization->hasAttr<DLLExportAttr>();
10435 if (Old_TSK == TSK_ImplicitInstantiation && NewlyDLLExported &&
10436 (Context.getTargetInfo().shouldDLLImportComdatSymbols() &&
10437 !Context.getTargetInfo().getTriple().isPS())) {
10438 // An explicit instantiation definition can add a dll attribute to a
10439 // template with a previous implicit instantiation. MinGW doesn't allow
10440 // this. We limit clang to only adding dllexport, to avoid potentially
10441 // strange codegen behavior. For example, if we extend this conditional
10442 // to dllimport, and we have a source file calling a method on an
10443 // implicitly instantiated template class instance and then declaring a
10444 // dllimport explicit instantiation definition for the same template
10445 // class, the codegen for the method call will not respect the dllimport,
10446 // while it will with cl. The Def will already have the DLL attribute,
10447 // since the Def and Specialization will be the same in the case of
10448 // Old_TSK == TSK_ImplicitInstantiation, and we already added the
10449 // attribute to the Specialization; we just need to make it take effect.
10450 assert(Def == Specialization &&
10451 "Def and Specialization should match for implicit instantiation");
10452 dllExportImportClassTemplateSpecialization(*this, Def);
10453 }
10454
10455 // In MinGW mode, export the template instantiation if the declaration
10456 // was marked dllexport.
10457 if (PrevDecl_TSK == TSK_ExplicitInstantiationDeclaration &&
10458 Context.getTargetInfo().getTriple().isWindowsGNUEnvironment() &&
10459 PrevDecl->hasAttr<DLLExportAttr>()) {
10460 dllExportImportClassTemplateSpecialization(*this, Def);
10461 }
10462
10463 // Set the template specialization kind. Make sure it is set before
10464 // instantiating the members which will trigger ASTConsumer callbacks.
10465 Specialization->setTemplateSpecializationKind(TSK);
10466 InstantiateClassTemplateSpecializationMembers(TemplateNameLoc, Def, TSK);
10467 } else {
10468
10469 // Set the template specialization kind.
10470 Specialization->setTemplateSpecializationKind(TSK);
10471 }
10472
10473 return Specialization;
10474 }
10475
10476 // Explicit instantiation of a member class of a class template.
10477 DeclResult
ActOnExplicitInstantiation(Scope * S,SourceLocation ExternLoc,SourceLocation TemplateLoc,unsigned TagSpec,SourceLocation KWLoc,CXXScopeSpec & SS,IdentifierInfo * Name,SourceLocation NameLoc,const ParsedAttributesView & Attr)10478 Sema::ActOnExplicitInstantiation(Scope *S, SourceLocation ExternLoc,
10479 SourceLocation TemplateLoc, unsigned TagSpec,
10480 SourceLocation KWLoc, CXXScopeSpec &SS,
10481 IdentifierInfo *Name, SourceLocation NameLoc,
10482 const ParsedAttributesView &Attr) {
10483
10484 bool Owned = false;
10485 bool IsDependent = false;
10486 Decl *TagD = ActOnTag(S, TagSpec, Sema::TUK_Reference, KWLoc, SS, Name,
10487 NameLoc, Attr, AS_none, /*ModulePrivateLoc=*/SourceLocation(),
10488 MultiTemplateParamsArg(), Owned, IsDependent, SourceLocation(),
10489 false, TypeResult(), /*IsTypeSpecifier*/ false,
10490 /*IsTemplateParamOrArg*/ false, /*OOK=*/OOK_Outside).get();
10491 assert(!IsDependent && "explicit instantiation of dependent name not yet handled");
10492
10493 if (!TagD)
10494 return true;
10495
10496 TagDecl *Tag = cast<TagDecl>(TagD);
10497 assert(!Tag->isEnum() && "shouldn't see enumerations here");
10498
10499 if (Tag->isInvalidDecl())
10500 return true;
10501
10502 CXXRecordDecl *Record = cast<CXXRecordDecl>(Tag);
10503 CXXRecordDecl *Pattern = Record->getInstantiatedFromMemberClass();
10504 if (!Pattern) {
10505 Diag(TemplateLoc, diag::err_explicit_instantiation_nontemplate_type)
10506 << Context.getTypeDeclType(Record);
10507 Diag(Record->getLocation(), diag::note_nontemplate_decl_here);
10508 return true;
10509 }
10510
10511 // C++0x [temp.explicit]p2:
10512 // If the explicit instantiation is for a class or member class, the
10513 // elaborated-type-specifier in the declaration shall include a
10514 // simple-template-id.
10515 //
10516 // C++98 has the same restriction, just worded differently.
10517 if (!ScopeSpecifierHasTemplateId(SS))
10518 Diag(TemplateLoc, diag::ext_explicit_instantiation_without_qualified_id)
10519 << Record << SS.getRange();
10520
10521 // C++0x [temp.explicit]p2:
10522 // There are two forms of explicit instantiation: an explicit instantiation
10523 // definition and an explicit instantiation declaration. An explicit
10524 // instantiation declaration begins with the extern keyword. [...]
10525 TemplateSpecializationKind TSK
10526 = ExternLoc.isInvalid()? TSK_ExplicitInstantiationDefinition
10527 : TSK_ExplicitInstantiationDeclaration;
10528
10529 CheckExplicitInstantiation(*this, Record, NameLoc, true, TSK);
10530
10531 // Verify that it is okay to explicitly instantiate here.
10532 CXXRecordDecl *PrevDecl
10533 = cast_or_null<CXXRecordDecl>(Record->getPreviousDecl());
10534 if (!PrevDecl && Record->getDefinition())
10535 PrevDecl = Record;
10536 if (PrevDecl) {
10537 MemberSpecializationInfo *MSInfo = PrevDecl->getMemberSpecializationInfo();
10538 bool HasNoEffect = false;
10539 assert(MSInfo && "No member specialization information?");
10540 if (CheckSpecializationInstantiationRedecl(TemplateLoc, TSK,
10541 PrevDecl,
10542 MSInfo->getTemplateSpecializationKind(),
10543 MSInfo->getPointOfInstantiation(),
10544 HasNoEffect))
10545 return true;
10546 if (HasNoEffect)
10547 return TagD;
10548 }
10549
10550 CXXRecordDecl *RecordDef
10551 = cast_or_null<CXXRecordDecl>(Record->getDefinition());
10552 if (!RecordDef) {
10553 // C++ [temp.explicit]p3:
10554 // A definition of a member class of a class template shall be in scope
10555 // at the point of an explicit instantiation of the member class.
10556 CXXRecordDecl *Def
10557 = cast_or_null<CXXRecordDecl>(Pattern->getDefinition());
10558 if (!Def) {
10559 Diag(TemplateLoc, diag::err_explicit_instantiation_undefined_member)
10560 << 0 << Record->getDeclName() << Record->getDeclContext();
10561 Diag(Pattern->getLocation(), diag::note_forward_declaration)
10562 << Pattern;
10563 return true;
10564 } else {
10565 if (InstantiateClass(NameLoc, Record, Def,
10566 getTemplateInstantiationArgs(Record),
10567 TSK))
10568 return true;
10569
10570 RecordDef = cast_or_null<CXXRecordDecl>(Record->getDefinition());
10571 if (!RecordDef)
10572 return true;
10573 }
10574 }
10575
10576 // Instantiate all of the members of the class.
10577 InstantiateClassMembers(NameLoc, RecordDef,
10578 getTemplateInstantiationArgs(Record), TSK);
10579
10580 if (TSK == TSK_ExplicitInstantiationDefinition)
10581 MarkVTableUsed(NameLoc, RecordDef, true);
10582
10583 // FIXME: We don't have any representation for explicit instantiations of
10584 // member classes. Such a representation is not needed for compilation, but it
10585 // should be available for clients that want to see all of the declarations in
10586 // the source code.
10587 return TagD;
10588 }
10589
ActOnExplicitInstantiation(Scope * S,SourceLocation ExternLoc,SourceLocation TemplateLoc,Declarator & D)10590 DeclResult Sema::ActOnExplicitInstantiation(Scope *S,
10591 SourceLocation ExternLoc,
10592 SourceLocation TemplateLoc,
10593 Declarator &D) {
10594 // Explicit instantiations always require a name.
10595 // TODO: check if/when DNInfo should replace Name.
10596 DeclarationNameInfo NameInfo = GetNameForDeclarator(D);
10597 DeclarationName Name = NameInfo.getName();
10598 if (!Name) {
10599 if (!D.isInvalidType())
10600 Diag(D.getDeclSpec().getBeginLoc(),
10601 diag::err_explicit_instantiation_requires_name)
10602 << D.getDeclSpec().getSourceRange() << D.getSourceRange();
10603
10604 return true;
10605 }
10606
10607 // The scope passed in may not be a decl scope. Zip up the scope tree until
10608 // we find one that is.
10609 while ((S->getFlags() & Scope::DeclScope) == 0 ||
10610 (S->getFlags() & Scope::TemplateParamScope) != 0)
10611 S = S->getParent();
10612
10613 // Determine the type of the declaration.
10614 TypeSourceInfo *T = GetTypeForDeclarator(D);
10615 QualType R = T->getType();
10616 if (R.isNull())
10617 return true;
10618
10619 // C++ [dcl.stc]p1:
10620 // A storage-class-specifier shall not be specified in [...] an explicit
10621 // instantiation (14.7.2) directive.
10622 if (D.getDeclSpec().getStorageClassSpec() == DeclSpec::SCS_typedef) {
10623 Diag(D.getIdentifierLoc(), diag::err_explicit_instantiation_of_typedef)
10624 << Name;
10625 return true;
10626 } else if (D.getDeclSpec().getStorageClassSpec()
10627 != DeclSpec::SCS_unspecified) {
10628 // Complain about then remove the storage class specifier.
10629 Diag(D.getIdentifierLoc(), diag::err_explicit_instantiation_storage_class)
10630 << FixItHint::CreateRemoval(D.getDeclSpec().getStorageClassSpecLoc());
10631
10632 D.getMutableDeclSpec().ClearStorageClassSpecs();
10633 }
10634
10635 // C++0x [temp.explicit]p1:
10636 // [...] An explicit instantiation of a function template shall not use the
10637 // inline or constexpr specifiers.
10638 // Presumably, this also applies to member functions of class templates as
10639 // well.
10640 if (D.getDeclSpec().isInlineSpecified())
10641 Diag(D.getDeclSpec().getInlineSpecLoc(),
10642 getLangOpts().CPlusPlus11 ?
10643 diag::err_explicit_instantiation_inline :
10644 diag::warn_explicit_instantiation_inline_0x)
10645 << FixItHint::CreateRemoval(D.getDeclSpec().getInlineSpecLoc());
10646 if (D.getDeclSpec().hasConstexprSpecifier() && R->isFunctionType())
10647 // FIXME: Add a fix-it to remove the 'constexpr' and add a 'const' if one is
10648 // not already specified.
10649 Diag(D.getDeclSpec().getConstexprSpecLoc(),
10650 diag::err_explicit_instantiation_constexpr);
10651
10652 // A deduction guide is not on the list of entities that can be explicitly
10653 // instantiated.
10654 if (Name.getNameKind() == DeclarationName::CXXDeductionGuideName) {
10655 Diag(D.getDeclSpec().getBeginLoc(), diag::err_deduction_guide_specialized)
10656 << /*explicit instantiation*/ 0;
10657 return true;
10658 }
10659
10660 // C++0x [temp.explicit]p2:
10661 // There are two forms of explicit instantiation: an explicit instantiation
10662 // definition and an explicit instantiation declaration. An explicit
10663 // instantiation declaration begins with the extern keyword. [...]
10664 TemplateSpecializationKind TSK
10665 = ExternLoc.isInvalid()? TSK_ExplicitInstantiationDefinition
10666 : TSK_ExplicitInstantiationDeclaration;
10667
10668 LookupResult Previous(*this, NameInfo, LookupOrdinaryName);
10669 LookupParsedName(Previous, S, &D.getCXXScopeSpec());
10670
10671 if (!R->isFunctionType()) {
10672 // C++ [temp.explicit]p1:
10673 // A [...] static data member of a class template can be explicitly
10674 // instantiated from the member definition associated with its class
10675 // template.
10676 // C++1y [temp.explicit]p1:
10677 // A [...] variable [...] template specialization can be explicitly
10678 // instantiated from its template.
10679 if (Previous.isAmbiguous())
10680 return true;
10681
10682 VarDecl *Prev = Previous.getAsSingle<VarDecl>();
10683 VarTemplateDecl *PrevTemplate = Previous.getAsSingle<VarTemplateDecl>();
10684
10685 if (!PrevTemplate) {
10686 if (!Prev || !Prev->isStaticDataMember()) {
10687 // We expect to see a static data member here.
10688 Diag(D.getIdentifierLoc(), diag::err_explicit_instantiation_not_known)
10689 << Name;
10690 for (LookupResult::iterator P = Previous.begin(), PEnd = Previous.end();
10691 P != PEnd; ++P)
10692 Diag((*P)->getLocation(), diag::note_explicit_instantiation_here);
10693 return true;
10694 }
10695
10696 if (!Prev->getInstantiatedFromStaticDataMember()) {
10697 // FIXME: Check for explicit specialization?
10698 Diag(D.getIdentifierLoc(),
10699 diag::err_explicit_instantiation_data_member_not_instantiated)
10700 << Prev;
10701 Diag(Prev->getLocation(), diag::note_explicit_instantiation_here);
10702 // FIXME: Can we provide a note showing where this was declared?
10703 return true;
10704 }
10705 } else {
10706 // Explicitly instantiate a variable template.
10707
10708 // C++1y [dcl.spec.auto]p6:
10709 // ... A program that uses auto or decltype(auto) in a context not
10710 // explicitly allowed in this section is ill-formed.
10711 //
10712 // This includes auto-typed variable template instantiations.
10713 if (R->isUndeducedType()) {
10714 Diag(T->getTypeLoc().getBeginLoc(),
10715 diag::err_auto_not_allowed_var_inst);
10716 return true;
10717 }
10718
10719 if (D.getName().getKind() != UnqualifiedIdKind::IK_TemplateId) {
10720 // C++1y [temp.explicit]p3:
10721 // If the explicit instantiation is for a variable, the unqualified-id
10722 // in the declaration shall be a template-id.
10723 Diag(D.getIdentifierLoc(),
10724 diag::err_explicit_instantiation_without_template_id)
10725 << PrevTemplate;
10726 Diag(PrevTemplate->getLocation(),
10727 diag::note_explicit_instantiation_here);
10728 return true;
10729 }
10730
10731 // Translate the parser's template argument list into our AST format.
10732 TemplateArgumentListInfo TemplateArgs =
10733 makeTemplateArgumentListInfo(*this, *D.getName().TemplateId);
10734
10735 DeclResult Res = CheckVarTemplateId(PrevTemplate, TemplateLoc,
10736 D.getIdentifierLoc(), TemplateArgs);
10737 if (Res.isInvalid())
10738 return true;
10739
10740 if (!Res.isUsable()) {
10741 // We somehow specified dependent template arguments in an explicit
10742 // instantiation. This should probably only happen during error
10743 // recovery.
10744 Diag(D.getIdentifierLoc(), diag::err_explicit_instantiation_dependent);
10745 return true;
10746 }
10747
10748 // Ignore access control bits, we don't need them for redeclaration
10749 // checking.
10750 Prev = cast<VarDecl>(Res.get());
10751 }
10752
10753 // C++0x [temp.explicit]p2:
10754 // If the explicit instantiation is for a member function, a member class
10755 // or a static data member of a class template specialization, the name of
10756 // the class template specialization in the qualified-id for the member
10757 // name shall be a simple-template-id.
10758 //
10759 // C++98 has the same restriction, just worded differently.
10760 //
10761 // This does not apply to variable template specializations, where the
10762 // template-id is in the unqualified-id instead.
10763 if (!ScopeSpecifierHasTemplateId(D.getCXXScopeSpec()) && !PrevTemplate)
10764 Diag(D.getIdentifierLoc(),
10765 diag::ext_explicit_instantiation_without_qualified_id)
10766 << Prev << D.getCXXScopeSpec().getRange();
10767
10768 CheckExplicitInstantiation(*this, Prev, D.getIdentifierLoc(), true, TSK);
10769
10770 // Verify that it is okay to explicitly instantiate here.
10771 TemplateSpecializationKind PrevTSK = Prev->getTemplateSpecializationKind();
10772 SourceLocation POI = Prev->getPointOfInstantiation();
10773 bool HasNoEffect = false;
10774 if (CheckSpecializationInstantiationRedecl(D.getIdentifierLoc(), TSK, Prev,
10775 PrevTSK, POI, HasNoEffect))
10776 return true;
10777
10778 if (!HasNoEffect) {
10779 // Instantiate static data member or variable template.
10780 Prev->setTemplateSpecializationKind(TSK, D.getIdentifierLoc());
10781 // Merge attributes.
10782 ProcessDeclAttributeList(S, Prev, D.getDeclSpec().getAttributes());
10783 if (TSK == TSK_ExplicitInstantiationDefinition)
10784 InstantiateVariableDefinition(D.getIdentifierLoc(), Prev);
10785 }
10786
10787 // Check the new variable specialization against the parsed input.
10788 if (PrevTemplate && !Context.hasSameType(Prev->getType(), R)) {
10789 Diag(T->getTypeLoc().getBeginLoc(),
10790 diag::err_invalid_var_template_spec_type)
10791 << 0 << PrevTemplate << R << Prev->getType();
10792 Diag(PrevTemplate->getLocation(), diag::note_template_declared_here)
10793 << 2 << PrevTemplate->getDeclName();
10794 return true;
10795 }
10796
10797 // FIXME: Create an ExplicitInstantiation node?
10798 return (Decl*) nullptr;
10799 }
10800
10801 // If the declarator is a template-id, translate the parser's template
10802 // argument list into our AST format.
10803 bool HasExplicitTemplateArgs = false;
10804 TemplateArgumentListInfo TemplateArgs;
10805 if (D.getName().getKind() == UnqualifiedIdKind::IK_TemplateId) {
10806 TemplateArgs = makeTemplateArgumentListInfo(*this, *D.getName().TemplateId);
10807 HasExplicitTemplateArgs = true;
10808 }
10809
10810 // C++ [temp.explicit]p1:
10811 // A [...] function [...] can be explicitly instantiated from its template.
10812 // A member function [...] of a class template can be explicitly
10813 // instantiated from the member definition associated with its class
10814 // template.
10815 UnresolvedSet<8> TemplateMatches;
10816 FunctionDecl *NonTemplateMatch = nullptr;
10817 TemplateSpecCandidateSet FailedCandidates(D.getIdentifierLoc());
10818 for (LookupResult::iterator P = Previous.begin(), PEnd = Previous.end();
10819 P != PEnd; ++P) {
10820 NamedDecl *Prev = *P;
10821 if (!HasExplicitTemplateArgs) {
10822 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Prev)) {
10823 QualType Adjusted = adjustCCAndNoReturn(R, Method->getType(),
10824 /*AdjustExceptionSpec*/true);
10825 if (Context.hasSameUnqualifiedType(Method->getType(), Adjusted)) {
10826 if (Method->getPrimaryTemplate()) {
10827 TemplateMatches.addDecl(Method, P.getAccess());
10828 } else {
10829 // FIXME: Can this assert ever happen? Needs a test.
10830 assert(!NonTemplateMatch && "Multiple NonTemplateMatches");
10831 NonTemplateMatch = Method;
10832 }
10833 }
10834 }
10835 }
10836
10837 FunctionTemplateDecl *FunTmpl = dyn_cast<FunctionTemplateDecl>(Prev);
10838 if (!FunTmpl)
10839 continue;
10840
10841 TemplateDeductionInfo Info(FailedCandidates.getLocation());
10842 FunctionDecl *Specialization = nullptr;
10843 if (TemplateDeductionResult TDK
10844 = DeduceTemplateArguments(FunTmpl,
10845 (HasExplicitTemplateArgs ? &TemplateArgs
10846 : nullptr),
10847 R, Specialization, Info)) {
10848 // Keep track of almost-matches.
10849 FailedCandidates.addCandidate()
10850 .set(P.getPair(), FunTmpl->getTemplatedDecl(),
10851 MakeDeductionFailureInfo(Context, TDK, Info));
10852 (void)TDK;
10853 continue;
10854 }
10855
10856 // Target attributes are part of the cuda function signature, so
10857 // the cuda target of the instantiated function must match that of its
10858 // template. Given that C++ template deduction does not take
10859 // target attributes into account, we reject candidates here that
10860 // have a different target.
10861 if (LangOpts.CUDA &&
10862 IdentifyCUDATarget(Specialization,
10863 /* IgnoreImplicitHDAttr = */ true) !=
10864 IdentifyCUDATarget(D.getDeclSpec().getAttributes())) {
10865 FailedCandidates.addCandidate().set(
10866 P.getPair(), FunTmpl->getTemplatedDecl(),
10867 MakeDeductionFailureInfo(Context, TDK_CUDATargetMismatch, Info));
10868 continue;
10869 }
10870
10871 TemplateMatches.addDecl(Specialization, P.getAccess());
10872 }
10873
10874 FunctionDecl *Specialization = NonTemplateMatch;
10875 if (!Specialization) {
10876 // Find the most specialized function template specialization.
10877 UnresolvedSetIterator Result = getMostSpecialized(
10878 TemplateMatches.begin(), TemplateMatches.end(), FailedCandidates,
10879 D.getIdentifierLoc(),
10880 PDiag(diag::err_explicit_instantiation_not_known) << Name,
10881 PDiag(diag::err_explicit_instantiation_ambiguous) << Name,
10882 PDiag(diag::note_explicit_instantiation_candidate));
10883
10884 if (Result == TemplateMatches.end())
10885 return true;
10886
10887 // Ignore access control bits, we don't need them for redeclaration checking.
10888 Specialization = cast<FunctionDecl>(*Result);
10889 }
10890
10891 // C++11 [except.spec]p4
10892 // In an explicit instantiation an exception-specification may be specified,
10893 // but is not required.
10894 // If an exception-specification is specified in an explicit instantiation
10895 // directive, it shall be compatible with the exception-specifications of
10896 // other declarations of that function.
10897 if (auto *FPT = R->getAs<FunctionProtoType>())
10898 if (FPT->hasExceptionSpec()) {
10899 unsigned DiagID =
10900 diag::err_mismatched_exception_spec_explicit_instantiation;
10901 if (getLangOpts().MicrosoftExt)
10902 DiagID = diag::ext_mismatched_exception_spec_explicit_instantiation;
10903 bool Result = CheckEquivalentExceptionSpec(
10904 PDiag(DiagID) << Specialization->getType(),
10905 PDiag(diag::note_explicit_instantiation_here),
10906 Specialization->getType()->getAs<FunctionProtoType>(),
10907 Specialization->getLocation(), FPT, D.getBeginLoc());
10908 // In Microsoft mode, mismatching exception specifications just cause a
10909 // warning.
10910 if (!getLangOpts().MicrosoftExt && Result)
10911 return true;
10912 }
10913
10914 if (Specialization->getTemplateSpecializationKind() == TSK_Undeclared) {
10915 Diag(D.getIdentifierLoc(),
10916 diag::err_explicit_instantiation_member_function_not_instantiated)
10917 << Specialization
10918 << (Specialization->getTemplateSpecializationKind() ==
10919 TSK_ExplicitSpecialization);
10920 Diag(Specialization->getLocation(), diag::note_explicit_instantiation_here);
10921 return true;
10922 }
10923
10924 FunctionDecl *PrevDecl = Specialization->getPreviousDecl();
10925 if (!PrevDecl && Specialization->isThisDeclarationADefinition())
10926 PrevDecl = Specialization;
10927
10928 if (PrevDecl) {
10929 bool HasNoEffect = false;
10930 if (CheckSpecializationInstantiationRedecl(D.getIdentifierLoc(), TSK,
10931 PrevDecl,
10932 PrevDecl->getTemplateSpecializationKind(),
10933 PrevDecl->getPointOfInstantiation(),
10934 HasNoEffect))
10935 return true;
10936
10937 // FIXME: We may still want to build some representation of this
10938 // explicit specialization.
10939 if (HasNoEffect)
10940 return (Decl*) nullptr;
10941 }
10942
10943 // HACK: libc++ has a bug where it attempts to explicitly instantiate the
10944 // functions
10945 // valarray<size_t>::valarray(size_t) and
10946 // valarray<size_t>::~valarray()
10947 // that it declared to have internal linkage with the internal_linkage
10948 // attribute. Ignore the explicit instantiation declaration in this case.
10949 if (Specialization->hasAttr<InternalLinkageAttr>() &&
10950 TSK == TSK_ExplicitInstantiationDeclaration) {
10951 if (auto *RD = dyn_cast<CXXRecordDecl>(Specialization->getDeclContext()))
10952 if (RD->getIdentifier() && RD->getIdentifier()->isStr("valarray") &&
10953 RD->isInStdNamespace())
10954 return (Decl*) nullptr;
10955 }
10956
10957 ProcessDeclAttributeList(S, Specialization, D.getDeclSpec().getAttributes());
10958
10959 // In MSVC mode, dllimported explicit instantiation definitions are treated as
10960 // instantiation declarations.
10961 if (TSK == TSK_ExplicitInstantiationDefinition &&
10962 Specialization->hasAttr<DLLImportAttr>() &&
10963 Context.getTargetInfo().getCXXABI().isMicrosoft())
10964 TSK = TSK_ExplicitInstantiationDeclaration;
10965
10966 Specialization->setTemplateSpecializationKind(TSK, D.getIdentifierLoc());
10967
10968 if (Specialization->isDefined()) {
10969 // Let the ASTConsumer know that this function has been explicitly
10970 // instantiated now, and its linkage might have changed.
10971 Consumer.HandleTopLevelDecl(DeclGroupRef(Specialization));
10972 } else if (TSK == TSK_ExplicitInstantiationDefinition)
10973 InstantiateFunctionDefinition(D.getIdentifierLoc(), Specialization);
10974
10975 // C++0x [temp.explicit]p2:
10976 // If the explicit instantiation is for a member function, a member class
10977 // or a static data member of a class template specialization, the name of
10978 // the class template specialization in the qualified-id for the member
10979 // name shall be a simple-template-id.
10980 //
10981 // C++98 has the same restriction, just worded differently.
10982 FunctionTemplateDecl *FunTmpl = Specialization->getPrimaryTemplate();
10983 if (D.getName().getKind() != UnqualifiedIdKind::IK_TemplateId && !FunTmpl &&
10984 D.getCXXScopeSpec().isSet() &&
10985 !ScopeSpecifierHasTemplateId(D.getCXXScopeSpec()))
10986 Diag(D.getIdentifierLoc(),
10987 diag::ext_explicit_instantiation_without_qualified_id)
10988 << Specialization << D.getCXXScopeSpec().getRange();
10989
10990 CheckExplicitInstantiation(
10991 *this,
10992 FunTmpl ? (NamedDecl *)FunTmpl
10993 : Specialization->getInstantiatedFromMemberFunction(),
10994 D.getIdentifierLoc(), D.getCXXScopeSpec().isSet(), TSK);
10995
10996 // FIXME: Create some kind of ExplicitInstantiationDecl here.
10997 return (Decl*) nullptr;
10998 }
10999
11000 TypeResult
ActOnDependentTag(Scope * S,unsigned TagSpec,TagUseKind TUK,const CXXScopeSpec & SS,IdentifierInfo * Name,SourceLocation TagLoc,SourceLocation NameLoc)11001 Sema::ActOnDependentTag(Scope *S, unsigned TagSpec, TagUseKind TUK,
11002 const CXXScopeSpec &SS, IdentifierInfo *Name,
11003 SourceLocation TagLoc, SourceLocation NameLoc) {
11004 // This has to hold, because SS is expected to be defined.
11005 assert(Name && "Expected a name in a dependent tag");
11006
11007 NestedNameSpecifier *NNS = SS.getScopeRep();
11008 if (!NNS)
11009 return true;
11010
11011 TagTypeKind Kind = TypeWithKeyword::getTagTypeKindForTypeSpec(TagSpec);
11012
11013 if (TUK == TUK_Declaration || TUK == TUK_Definition) {
11014 Diag(NameLoc, diag::err_dependent_tag_decl)
11015 << (TUK == TUK_Definition) << llvm::to_underlying(Kind)
11016 << SS.getRange();
11017 return true;
11018 }
11019
11020 // Create the resulting type.
11021 ElaboratedTypeKeyword Kwd = TypeWithKeyword::getKeywordForTagTypeKind(Kind);
11022 QualType Result = Context.getDependentNameType(Kwd, NNS, Name);
11023
11024 // Create type-source location information for this type.
11025 TypeLocBuilder TLB;
11026 DependentNameTypeLoc TL = TLB.push<DependentNameTypeLoc>(Result);
11027 TL.setElaboratedKeywordLoc(TagLoc);
11028 TL.setQualifierLoc(SS.getWithLocInContext(Context));
11029 TL.setNameLoc(NameLoc);
11030 return CreateParsedType(Result, TLB.getTypeSourceInfo(Context, Result));
11031 }
11032
ActOnTypenameType(Scope * S,SourceLocation TypenameLoc,const CXXScopeSpec & SS,const IdentifierInfo & II,SourceLocation IdLoc,ImplicitTypenameContext IsImplicitTypename)11033 TypeResult Sema::ActOnTypenameType(Scope *S, SourceLocation TypenameLoc,
11034 const CXXScopeSpec &SS,
11035 const IdentifierInfo &II,
11036 SourceLocation IdLoc,
11037 ImplicitTypenameContext IsImplicitTypename) {
11038 if (SS.isInvalid())
11039 return true;
11040
11041 if (TypenameLoc.isValid() && S && !S->getTemplateParamParent())
11042 Diag(TypenameLoc,
11043 getLangOpts().CPlusPlus11 ?
11044 diag::warn_cxx98_compat_typename_outside_of_template :
11045 diag::ext_typename_outside_of_template)
11046 << FixItHint::CreateRemoval(TypenameLoc);
11047
11048 NestedNameSpecifierLoc QualifierLoc = SS.getWithLocInContext(Context);
11049 TypeSourceInfo *TSI = nullptr;
11050 QualType T =
11051 CheckTypenameType((TypenameLoc.isValid() ||
11052 IsImplicitTypename == ImplicitTypenameContext::Yes)
11053 ? ElaboratedTypeKeyword::Typename
11054 : ElaboratedTypeKeyword::None,
11055 TypenameLoc, QualifierLoc, II, IdLoc, &TSI,
11056 /*DeducedTSTContext=*/true);
11057 if (T.isNull())
11058 return true;
11059 return CreateParsedType(T, TSI);
11060 }
11061
11062 TypeResult
ActOnTypenameType(Scope * S,SourceLocation TypenameLoc,const CXXScopeSpec & SS,SourceLocation TemplateKWLoc,TemplateTy TemplateIn,IdentifierInfo * TemplateII,SourceLocation TemplateIILoc,SourceLocation LAngleLoc,ASTTemplateArgsPtr TemplateArgsIn,SourceLocation RAngleLoc)11063 Sema::ActOnTypenameType(Scope *S,
11064 SourceLocation TypenameLoc,
11065 const CXXScopeSpec &SS,
11066 SourceLocation TemplateKWLoc,
11067 TemplateTy TemplateIn,
11068 IdentifierInfo *TemplateII,
11069 SourceLocation TemplateIILoc,
11070 SourceLocation LAngleLoc,
11071 ASTTemplateArgsPtr TemplateArgsIn,
11072 SourceLocation RAngleLoc) {
11073 if (TypenameLoc.isValid() && S && !S->getTemplateParamParent())
11074 Diag(TypenameLoc,
11075 getLangOpts().CPlusPlus11 ?
11076 diag::warn_cxx98_compat_typename_outside_of_template :
11077 diag::ext_typename_outside_of_template)
11078 << FixItHint::CreateRemoval(TypenameLoc);
11079
11080 // Strangely, non-type results are not ignored by this lookup, so the
11081 // program is ill-formed if it finds an injected-class-name.
11082 if (TypenameLoc.isValid()) {
11083 auto *LookupRD =
11084 dyn_cast_or_null<CXXRecordDecl>(computeDeclContext(SS, false));
11085 if (LookupRD && LookupRD->getIdentifier() == TemplateII) {
11086 Diag(TemplateIILoc,
11087 diag::ext_out_of_line_qualified_id_type_names_constructor)
11088 << TemplateII << 0 /*injected-class-name used as template name*/
11089 << (TemplateKWLoc.isValid() ? 1 : 0 /*'template'/'typename' keyword*/);
11090 }
11091 }
11092
11093 // Translate the parser's template argument list in our AST format.
11094 TemplateArgumentListInfo TemplateArgs(LAngleLoc, RAngleLoc);
11095 translateTemplateArguments(TemplateArgsIn, TemplateArgs);
11096
11097 TemplateName Template = TemplateIn.get();
11098 if (DependentTemplateName *DTN = Template.getAsDependentTemplateName()) {
11099 // Construct a dependent template specialization type.
11100 assert(DTN && "dependent template has non-dependent name?");
11101 assert(DTN->getQualifier() == SS.getScopeRep());
11102 QualType T = Context.getDependentTemplateSpecializationType(
11103 ElaboratedTypeKeyword::Typename, DTN->getQualifier(),
11104 DTN->getIdentifier(), TemplateArgs.arguments());
11105
11106 // Create source-location information for this type.
11107 TypeLocBuilder Builder;
11108 DependentTemplateSpecializationTypeLoc SpecTL
11109 = Builder.push<DependentTemplateSpecializationTypeLoc>(T);
11110 SpecTL.setElaboratedKeywordLoc(TypenameLoc);
11111 SpecTL.setQualifierLoc(SS.getWithLocInContext(Context));
11112 SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
11113 SpecTL.setTemplateNameLoc(TemplateIILoc);
11114 SpecTL.setLAngleLoc(LAngleLoc);
11115 SpecTL.setRAngleLoc(RAngleLoc);
11116 for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I)
11117 SpecTL.setArgLocInfo(I, TemplateArgs[I].getLocInfo());
11118 return CreateParsedType(T, Builder.getTypeSourceInfo(Context, T));
11119 }
11120
11121 QualType T = CheckTemplateIdType(Template, TemplateIILoc, TemplateArgs);
11122 if (T.isNull())
11123 return true;
11124
11125 // Provide source-location information for the template specialization type.
11126 TypeLocBuilder Builder;
11127 TemplateSpecializationTypeLoc SpecTL
11128 = Builder.push<TemplateSpecializationTypeLoc>(T);
11129 SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
11130 SpecTL.setTemplateNameLoc(TemplateIILoc);
11131 SpecTL.setLAngleLoc(LAngleLoc);
11132 SpecTL.setRAngleLoc(RAngleLoc);
11133 for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I)
11134 SpecTL.setArgLocInfo(I, TemplateArgs[I].getLocInfo());
11135
11136 T = Context.getElaboratedType(ElaboratedTypeKeyword::Typename,
11137 SS.getScopeRep(), T);
11138 ElaboratedTypeLoc TL = Builder.push<ElaboratedTypeLoc>(T);
11139 TL.setElaboratedKeywordLoc(TypenameLoc);
11140 TL.setQualifierLoc(SS.getWithLocInContext(Context));
11141
11142 TypeSourceInfo *TSI = Builder.getTypeSourceInfo(Context, T);
11143 return CreateParsedType(T, TSI);
11144 }
11145
11146
11147 /// Determine whether this failed name lookup should be treated as being
11148 /// disabled by a usage of std::enable_if.
isEnableIf(NestedNameSpecifierLoc NNS,const IdentifierInfo & II,SourceRange & CondRange,Expr * & Cond)11149 static bool isEnableIf(NestedNameSpecifierLoc NNS, const IdentifierInfo &II,
11150 SourceRange &CondRange, Expr *&Cond) {
11151 // We must be looking for a ::type...
11152 if (!II.isStr("type"))
11153 return false;
11154
11155 // ... within an explicitly-written template specialization...
11156 if (!NNS || !NNS.getNestedNameSpecifier()->getAsType())
11157 return false;
11158 TypeLoc EnableIfTy = NNS.getTypeLoc();
11159 TemplateSpecializationTypeLoc EnableIfTSTLoc =
11160 EnableIfTy.getAs<TemplateSpecializationTypeLoc>();
11161 if (!EnableIfTSTLoc || EnableIfTSTLoc.getNumArgs() == 0)
11162 return false;
11163 const TemplateSpecializationType *EnableIfTST = EnableIfTSTLoc.getTypePtr();
11164
11165 // ... which names a complete class template declaration...
11166 const TemplateDecl *EnableIfDecl =
11167 EnableIfTST->getTemplateName().getAsTemplateDecl();
11168 if (!EnableIfDecl || EnableIfTST->isIncompleteType())
11169 return false;
11170
11171 // ... called "enable_if".
11172 const IdentifierInfo *EnableIfII =
11173 EnableIfDecl->getDeclName().getAsIdentifierInfo();
11174 if (!EnableIfII || !EnableIfII->isStr("enable_if"))
11175 return false;
11176
11177 // Assume the first template argument is the condition.
11178 CondRange = EnableIfTSTLoc.getArgLoc(0).getSourceRange();
11179
11180 // Dig out the condition.
11181 Cond = nullptr;
11182 if (EnableIfTSTLoc.getArgLoc(0).getArgument().getKind()
11183 != TemplateArgument::Expression)
11184 return true;
11185
11186 Cond = EnableIfTSTLoc.getArgLoc(0).getSourceExpression();
11187
11188 // Ignore Boolean literals; they add no value.
11189 if (isa<CXXBoolLiteralExpr>(Cond->IgnoreParenCasts()))
11190 Cond = nullptr;
11191
11192 return true;
11193 }
11194
11195 QualType
CheckTypenameType(ElaboratedTypeKeyword Keyword,SourceLocation KeywordLoc,NestedNameSpecifierLoc QualifierLoc,const IdentifierInfo & II,SourceLocation IILoc,TypeSourceInfo ** TSI,bool DeducedTSTContext)11196 Sema::CheckTypenameType(ElaboratedTypeKeyword Keyword,
11197 SourceLocation KeywordLoc,
11198 NestedNameSpecifierLoc QualifierLoc,
11199 const IdentifierInfo &II,
11200 SourceLocation IILoc,
11201 TypeSourceInfo **TSI,
11202 bool DeducedTSTContext) {
11203 QualType T = CheckTypenameType(Keyword, KeywordLoc, QualifierLoc, II, IILoc,
11204 DeducedTSTContext);
11205 if (T.isNull())
11206 return QualType();
11207
11208 *TSI = Context.CreateTypeSourceInfo(T);
11209 if (isa<DependentNameType>(T)) {
11210 DependentNameTypeLoc TL =
11211 (*TSI)->getTypeLoc().castAs<DependentNameTypeLoc>();
11212 TL.setElaboratedKeywordLoc(KeywordLoc);
11213 TL.setQualifierLoc(QualifierLoc);
11214 TL.setNameLoc(IILoc);
11215 } else {
11216 ElaboratedTypeLoc TL = (*TSI)->getTypeLoc().castAs<ElaboratedTypeLoc>();
11217 TL.setElaboratedKeywordLoc(KeywordLoc);
11218 TL.setQualifierLoc(QualifierLoc);
11219 TL.getNamedTypeLoc().castAs<TypeSpecTypeLoc>().setNameLoc(IILoc);
11220 }
11221 return T;
11222 }
11223
11224 /// Build the type that describes a C++ typename specifier,
11225 /// e.g., "typename T::type".
11226 QualType
CheckTypenameType(ElaboratedTypeKeyword Keyword,SourceLocation KeywordLoc,NestedNameSpecifierLoc QualifierLoc,const IdentifierInfo & II,SourceLocation IILoc,bool DeducedTSTContext)11227 Sema::CheckTypenameType(ElaboratedTypeKeyword Keyword,
11228 SourceLocation KeywordLoc,
11229 NestedNameSpecifierLoc QualifierLoc,
11230 const IdentifierInfo &II,
11231 SourceLocation IILoc, bool DeducedTSTContext) {
11232 CXXScopeSpec SS;
11233 SS.Adopt(QualifierLoc);
11234
11235 DeclContext *Ctx = nullptr;
11236 if (QualifierLoc) {
11237 Ctx = computeDeclContext(SS);
11238 if (!Ctx) {
11239 // If the nested-name-specifier is dependent and couldn't be
11240 // resolved to a type, build a typename type.
11241 assert(QualifierLoc.getNestedNameSpecifier()->isDependent());
11242 return Context.getDependentNameType(Keyword,
11243 QualifierLoc.getNestedNameSpecifier(),
11244 &II);
11245 }
11246
11247 // If the nested-name-specifier refers to the current instantiation,
11248 // the "typename" keyword itself is superfluous. In C++03, the
11249 // program is actually ill-formed. However, DR 382 (in C++0x CD1)
11250 // allows such extraneous "typename" keywords, and we retroactively
11251 // apply this DR to C++03 code with only a warning. In any case we continue.
11252
11253 if (RequireCompleteDeclContext(SS, Ctx))
11254 return QualType();
11255 }
11256
11257 DeclarationName Name(&II);
11258 LookupResult Result(*this, Name, IILoc, LookupOrdinaryName);
11259 if (Ctx)
11260 LookupQualifiedName(Result, Ctx, SS);
11261 else
11262 LookupName(Result, CurScope);
11263 unsigned DiagID = 0;
11264 Decl *Referenced = nullptr;
11265 switch (Result.getResultKind()) {
11266 case LookupResult::NotFound: {
11267 // If we're looking up 'type' within a template named 'enable_if', produce
11268 // a more specific diagnostic.
11269 SourceRange CondRange;
11270 Expr *Cond = nullptr;
11271 if (Ctx && isEnableIf(QualifierLoc, II, CondRange, Cond)) {
11272 // If we have a condition, narrow it down to the specific failed
11273 // condition.
11274 if (Cond) {
11275 Expr *FailedCond;
11276 std::string FailedDescription;
11277 std::tie(FailedCond, FailedDescription) =
11278 findFailedBooleanCondition(Cond);
11279
11280 Diag(FailedCond->getExprLoc(),
11281 diag::err_typename_nested_not_found_requirement)
11282 << FailedDescription
11283 << FailedCond->getSourceRange();
11284 return QualType();
11285 }
11286
11287 Diag(CondRange.getBegin(),
11288 diag::err_typename_nested_not_found_enable_if)
11289 << Ctx << CondRange;
11290 return QualType();
11291 }
11292
11293 DiagID = Ctx ? diag::err_typename_nested_not_found
11294 : diag::err_unknown_typename;
11295 break;
11296 }
11297
11298 case LookupResult::FoundUnresolvedValue: {
11299 // We found a using declaration that is a value. Most likely, the using
11300 // declaration itself is meant to have the 'typename' keyword.
11301 SourceRange FullRange(KeywordLoc.isValid() ? KeywordLoc : SS.getBeginLoc(),
11302 IILoc);
11303 Diag(IILoc, diag::err_typename_refers_to_using_value_decl)
11304 << Name << Ctx << FullRange;
11305 if (UnresolvedUsingValueDecl *Using
11306 = dyn_cast<UnresolvedUsingValueDecl>(Result.getRepresentativeDecl())){
11307 SourceLocation Loc = Using->getQualifierLoc().getBeginLoc();
11308 Diag(Loc, diag::note_using_value_decl_missing_typename)
11309 << FixItHint::CreateInsertion(Loc, "typename ");
11310 }
11311 }
11312 // Fall through to create a dependent typename type, from which we can recover
11313 // better.
11314 [[fallthrough]];
11315
11316 case LookupResult::NotFoundInCurrentInstantiation:
11317 // Okay, it's a member of an unknown instantiation.
11318 return Context.getDependentNameType(Keyword,
11319 QualifierLoc.getNestedNameSpecifier(),
11320 &II);
11321
11322 case LookupResult::Found:
11323 if (TypeDecl *Type = dyn_cast<TypeDecl>(Result.getFoundDecl())) {
11324 // C++ [class.qual]p2:
11325 // In a lookup in which function names are not ignored and the
11326 // nested-name-specifier nominates a class C, if the name specified
11327 // after the nested-name-specifier, when looked up in C, is the
11328 // injected-class-name of C [...] then the name is instead considered
11329 // to name the constructor of class C.
11330 //
11331 // Unlike in an elaborated-type-specifier, function names are not ignored
11332 // in typename-specifier lookup. However, they are ignored in all the
11333 // contexts where we form a typename type with no keyword (that is, in
11334 // mem-initializer-ids, base-specifiers, and elaborated-type-specifiers).
11335 //
11336 // FIXME: That's not strictly true: mem-initializer-id lookup does not
11337 // ignore functions, but that appears to be an oversight.
11338 auto *LookupRD = dyn_cast_or_null<CXXRecordDecl>(Ctx);
11339 auto *FoundRD = dyn_cast<CXXRecordDecl>(Type);
11340 if (Keyword == ElaboratedTypeKeyword::Typename && LookupRD && FoundRD &&
11341 FoundRD->isInjectedClassName() &&
11342 declaresSameEntity(LookupRD, cast<Decl>(FoundRD->getParent())))
11343 Diag(IILoc, diag::ext_out_of_line_qualified_id_type_names_constructor)
11344 << &II << 1 << 0 /*'typename' keyword used*/;
11345
11346 // We found a type. Build an ElaboratedType, since the
11347 // typename-specifier was just sugar.
11348 MarkAnyDeclReferenced(Type->getLocation(), Type, /*OdrUse=*/false);
11349 return Context.getElaboratedType(Keyword,
11350 QualifierLoc.getNestedNameSpecifier(),
11351 Context.getTypeDeclType(Type));
11352 }
11353
11354 // C++ [dcl.type.simple]p2:
11355 // A type-specifier of the form
11356 // typename[opt] nested-name-specifier[opt] template-name
11357 // is a placeholder for a deduced class type [...].
11358 if (getLangOpts().CPlusPlus17) {
11359 if (auto *TD = getAsTypeTemplateDecl(Result.getFoundDecl())) {
11360 if (!DeducedTSTContext) {
11361 QualType T(QualifierLoc
11362 ? QualifierLoc.getNestedNameSpecifier()->getAsType()
11363 : nullptr, 0);
11364 if (!T.isNull())
11365 Diag(IILoc, diag::err_dependent_deduced_tst)
11366 << (int)getTemplateNameKindForDiagnostics(TemplateName(TD)) << T;
11367 else
11368 Diag(IILoc, diag::err_deduced_tst)
11369 << (int)getTemplateNameKindForDiagnostics(TemplateName(TD));
11370 NoteTemplateLocation(*TD);
11371 return QualType();
11372 }
11373 return Context.getElaboratedType(
11374 Keyword, QualifierLoc.getNestedNameSpecifier(),
11375 Context.getDeducedTemplateSpecializationType(TemplateName(TD),
11376 QualType(), false));
11377 }
11378 }
11379
11380 DiagID = Ctx ? diag::err_typename_nested_not_type
11381 : diag::err_typename_not_type;
11382 Referenced = Result.getFoundDecl();
11383 break;
11384
11385 case LookupResult::FoundOverloaded:
11386 DiagID = Ctx ? diag::err_typename_nested_not_type
11387 : diag::err_typename_not_type;
11388 Referenced = *Result.begin();
11389 break;
11390
11391 case LookupResult::Ambiguous:
11392 return QualType();
11393 }
11394
11395 // If we get here, it's because name lookup did not find a
11396 // type. Emit an appropriate diagnostic and return an error.
11397 SourceRange FullRange(KeywordLoc.isValid() ? KeywordLoc : SS.getBeginLoc(),
11398 IILoc);
11399 if (Ctx)
11400 Diag(IILoc, DiagID) << FullRange << Name << Ctx;
11401 else
11402 Diag(IILoc, DiagID) << FullRange << Name;
11403 if (Referenced)
11404 Diag(Referenced->getLocation(),
11405 Ctx ? diag::note_typename_member_refers_here
11406 : diag::note_typename_refers_here)
11407 << Name;
11408 return QualType();
11409 }
11410
11411 namespace {
11412 // See Sema::RebuildTypeInCurrentInstantiation
11413 class CurrentInstantiationRebuilder
11414 : public TreeTransform<CurrentInstantiationRebuilder> {
11415 SourceLocation Loc;
11416 DeclarationName Entity;
11417
11418 public:
11419 typedef TreeTransform<CurrentInstantiationRebuilder> inherited;
11420
CurrentInstantiationRebuilder(Sema & SemaRef,SourceLocation Loc,DeclarationName Entity)11421 CurrentInstantiationRebuilder(Sema &SemaRef,
11422 SourceLocation Loc,
11423 DeclarationName Entity)
11424 : TreeTransform<CurrentInstantiationRebuilder>(SemaRef),
11425 Loc(Loc), Entity(Entity) { }
11426
11427 /// Determine whether the given type \p T has already been
11428 /// transformed.
11429 ///
11430 /// For the purposes of type reconstruction, a type has already been
11431 /// transformed if it is NULL or if it is not dependent.
AlreadyTransformed(QualType T)11432 bool AlreadyTransformed(QualType T) {
11433 return T.isNull() || !T->isInstantiationDependentType();
11434 }
11435
11436 /// Returns the location of the entity whose type is being
11437 /// rebuilt.
getBaseLocation()11438 SourceLocation getBaseLocation() { return Loc; }
11439
11440 /// Returns the name of the entity whose type is being rebuilt.
getBaseEntity()11441 DeclarationName getBaseEntity() { return Entity; }
11442
11443 /// Sets the "base" location and entity when that
11444 /// information is known based on another transformation.
setBase(SourceLocation Loc,DeclarationName Entity)11445 void setBase(SourceLocation Loc, DeclarationName Entity) {
11446 this->Loc = Loc;
11447 this->Entity = Entity;
11448 }
11449
TransformLambdaExpr(LambdaExpr * E)11450 ExprResult TransformLambdaExpr(LambdaExpr *E) {
11451 // Lambdas never need to be transformed.
11452 return E;
11453 }
11454 };
11455 } // end anonymous namespace
11456
11457 /// Rebuilds a type within the context of the current instantiation.
11458 ///
11459 /// The type \p T is part of the type of an out-of-line member definition of
11460 /// a class template (or class template partial specialization) that was parsed
11461 /// and constructed before we entered the scope of the class template (or
11462 /// partial specialization thereof). This routine will rebuild that type now
11463 /// that we have entered the declarator's scope, which may produce different
11464 /// canonical types, e.g.,
11465 ///
11466 /// \code
11467 /// template<typename T>
11468 /// struct X {
11469 /// typedef T* pointer;
11470 /// pointer data();
11471 /// };
11472 ///
11473 /// template<typename T>
11474 /// typename X<T>::pointer X<T>::data() { ... }
11475 /// \endcode
11476 ///
11477 /// Here, the type "typename X<T>::pointer" will be created as a DependentNameType,
11478 /// since we do not know that we can look into X<T> when we parsed the type.
11479 /// This function will rebuild the type, performing the lookup of "pointer"
11480 /// in X<T> and returning an ElaboratedType whose canonical type is the same
11481 /// as the canonical type of T*, allowing the return types of the out-of-line
11482 /// definition and the declaration to match.
RebuildTypeInCurrentInstantiation(TypeSourceInfo * T,SourceLocation Loc,DeclarationName Name)11483 TypeSourceInfo *Sema::RebuildTypeInCurrentInstantiation(TypeSourceInfo *T,
11484 SourceLocation Loc,
11485 DeclarationName Name) {
11486 if (!T || !T->getType()->isInstantiationDependentType())
11487 return T;
11488
11489 CurrentInstantiationRebuilder Rebuilder(*this, Loc, Name);
11490 return Rebuilder.TransformType(T);
11491 }
11492
RebuildExprInCurrentInstantiation(Expr * E)11493 ExprResult Sema::RebuildExprInCurrentInstantiation(Expr *E) {
11494 CurrentInstantiationRebuilder Rebuilder(*this, E->getExprLoc(),
11495 DeclarationName());
11496 return Rebuilder.TransformExpr(E);
11497 }
11498
RebuildNestedNameSpecifierInCurrentInstantiation(CXXScopeSpec & SS)11499 bool Sema::RebuildNestedNameSpecifierInCurrentInstantiation(CXXScopeSpec &SS) {
11500 if (SS.isInvalid())
11501 return true;
11502
11503 NestedNameSpecifierLoc QualifierLoc = SS.getWithLocInContext(Context);
11504 CurrentInstantiationRebuilder Rebuilder(*this, SS.getRange().getBegin(),
11505 DeclarationName());
11506 NestedNameSpecifierLoc Rebuilt
11507 = Rebuilder.TransformNestedNameSpecifierLoc(QualifierLoc);
11508 if (!Rebuilt)
11509 return true;
11510
11511 SS.Adopt(Rebuilt);
11512 return false;
11513 }
11514
11515 /// Rebuild the template parameters now that we know we're in a current
11516 /// instantiation.
RebuildTemplateParamsInCurrentInstantiation(TemplateParameterList * Params)11517 bool Sema::RebuildTemplateParamsInCurrentInstantiation(
11518 TemplateParameterList *Params) {
11519 for (unsigned I = 0, N = Params->size(); I != N; ++I) {
11520 Decl *Param = Params->getParam(I);
11521
11522 // There is nothing to rebuild in a type parameter.
11523 if (isa<TemplateTypeParmDecl>(Param))
11524 continue;
11525
11526 // Rebuild the template parameter list of a template template parameter.
11527 if (TemplateTemplateParmDecl *TTP
11528 = dyn_cast<TemplateTemplateParmDecl>(Param)) {
11529 if (RebuildTemplateParamsInCurrentInstantiation(
11530 TTP->getTemplateParameters()))
11531 return true;
11532
11533 continue;
11534 }
11535
11536 // Rebuild the type of a non-type template parameter.
11537 NonTypeTemplateParmDecl *NTTP = cast<NonTypeTemplateParmDecl>(Param);
11538 TypeSourceInfo *NewTSI
11539 = RebuildTypeInCurrentInstantiation(NTTP->getTypeSourceInfo(),
11540 NTTP->getLocation(),
11541 NTTP->getDeclName());
11542 if (!NewTSI)
11543 return true;
11544
11545 if (NewTSI->getType()->isUndeducedType()) {
11546 // C++17 [temp.dep.expr]p3:
11547 // An id-expression is type-dependent if it contains
11548 // - an identifier associated by name lookup with a non-type
11549 // template-parameter declared with a type that contains a
11550 // placeholder type (7.1.7.4),
11551 NewTSI = SubstAutoTypeSourceInfoDependent(NewTSI);
11552 }
11553
11554 if (NewTSI != NTTP->getTypeSourceInfo()) {
11555 NTTP->setTypeSourceInfo(NewTSI);
11556 NTTP->setType(NewTSI->getType());
11557 }
11558 }
11559
11560 return false;
11561 }
11562
11563 /// Produces a formatted string that describes the binding of
11564 /// template parameters to template arguments.
11565 std::string
getTemplateArgumentBindingsText(const TemplateParameterList * Params,const TemplateArgumentList & Args)11566 Sema::getTemplateArgumentBindingsText(const TemplateParameterList *Params,
11567 const TemplateArgumentList &Args) {
11568 return getTemplateArgumentBindingsText(Params, Args.data(), Args.size());
11569 }
11570
11571 std::string
getTemplateArgumentBindingsText(const TemplateParameterList * Params,const TemplateArgument * Args,unsigned NumArgs)11572 Sema::getTemplateArgumentBindingsText(const TemplateParameterList *Params,
11573 const TemplateArgument *Args,
11574 unsigned NumArgs) {
11575 SmallString<128> Str;
11576 llvm::raw_svector_ostream Out(Str);
11577
11578 if (!Params || Params->size() == 0 || NumArgs == 0)
11579 return std::string();
11580
11581 for (unsigned I = 0, N = Params->size(); I != N; ++I) {
11582 if (I >= NumArgs)
11583 break;
11584
11585 if (I == 0)
11586 Out << "[with ";
11587 else
11588 Out << ", ";
11589
11590 if (const IdentifierInfo *Id = Params->getParam(I)->getIdentifier()) {
11591 Out << Id->getName();
11592 } else {
11593 Out << '$' << I;
11594 }
11595
11596 Out << " = ";
11597 Args[I].print(getPrintingPolicy(), Out,
11598 TemplateParameterList::shouldIncludeTypeForArgument(
11599 getPrintingPolicy(), Params, I));
11600 }
11601
11602 Out << ']';
11603 return std::string(Out.str());
11604 }
11605
MarkAsLateParsedTemplate(FunctionDecl * FD,Decl * FnD,CachedTokens & Toks)11606 void Sema::MarkAsLateParsedTemplate(FunctionDecl *FD, Decl *FnD,
11607 CachedTokens &Toks) {
11608 if (!FD)
11609 return;
11610
11611 auto LPT = std::make_unique<LateParsedTemplate>();
11612
11613 // Take tokens to avoid allocations
11614 LPT->Toks.swap(Toks);
11615 LPT->D = FnD;
11616 LPT->FPO = getCurFPFeatures();
11617 LateParsedTemplateMap.insert(std::make_pair(FD, std::move(LPT)));
11618
11619 FD->setLateTemplateParsed(true);
11620 }
11621
UnmarkAsLateParsedTemplate(FunctionDecl * FD)11622 void Sema::UnmarkAsLateParsedTemplate(FunctionDecl *FD) {
11623 if (!FD)
11624 return;
11625 FD->setLateTemplateParsed(false);
11626 }
11627
IsInsideALocalClassWithinATemplateFunction()11628 bool Sema::IsInsideALocalClassWithinATemplateFunction() {
11629 DeclContext *DC = CurContext;
11630
11631 while (DC) {
11632 if (CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(CurContext)) {
11633 const FunctionDecl *FD = RD->isLocalClass();
11634 return (FD && FD->getTemplatedKind() != FunctionDecl::TK_NonTemplate);
11635 } else if (DC->isTranslationUnit() || DC->isNamespace())
11636 return false;
11637
11638 DC = DC->getParent();
11639 }
11640 return false;
11641 }
11642
11643 namespace {
11644 /// Walk the path from which a declaration was instantiated, and check
11645 /// that every explicit specialization along that path is visible. This enforces
11646 /// C++ [temp.expl.spec]/6:
11647 ///
11648 /// If a template, a member template or a member of a class template is
11649 /// explicitly specialized then that specialization shall be declared before
11650 /// the first use of that specialization that would cause an implicit
11651 /// instantiation to take place, in every translation unit in which such a
11652 /// use occurs; no diagnostic is required.
11653 ///
11654 /// and also C++ [temp.class.spec]/1:
11655 ///
11656 /// A partial specialization shall be declared before the first use of a
11657 /// class template specialization that would make use of the partial
11658 /// specialization as the result of an implicit or explicit instantiation
11659 /// in every translation unit in which such a use occurs; no diagnostic is
11660 /// required.
11661 class ExplicitSpecializationVisibilityChecker {
11662 Sema &S;
11663 SourceLocation Loc;
11664 llvm::SmallVector<Module *, 8> Modules;
11665 Sema::AcceptableKind Kind;
11666
11667 public:
ExplicitSpecializationVisibilityChecker(Sema & S,SourceLocation Loc,Sema::AcceptableKind Kind)11668 ExplicitSpecializationVisibilityChecker(Sema &S, SourceLocation Loc,
11669 Sema::AcceptableKind Kind)
11670 : S(S), Loc(Loc), Kind(Kind) {}
11671
check(NamedDecl * ND)11672 void check(NamedDecl *ND) {
11673 if (auto *FD = dyn_cast<FunctionDecl>(ND))
11674 return checkImpl(FD);
11675 if (auto *RD = dyn_cast<CXXRecordDecl>(ND))
11676 return checkImpl(RD);
11677 if (auto *VD = dyn_cast<VarDecl>(ND))
11678 return checkImpl(VD);
11679 if (auto *ED = dyn_cast<EnumDecl>(ND))
11680 return checkImpl(ED);
11681 }
11682
11683 private:
diagnose(NamedDecl * D,bool IsPartialSpec)11684 void diagnose(NamedDecl *D, bool IsPartialSpec) {
11685 auto Kind = IsPartialSpec ? Sema::MissingImportKind::PartialSpecialization
11686 : Sema::MissingImportKind::ExplicitSpecialization;
11687 const bool Recover = true;
11688
11689 // If we got a custom set of modules (because only a subset of the
11690 // declarations are interesting), use them, otherwise let
11691 // diagnoseMissingImport intelligently pick some.
11692 if (Modules.empty())
11693 S.diagnoseMissingImport(Loc, D, Kind, Recover);
11694 else
11695 S.diagnoseMissingImport(Loc, D, D->getLocation(), Modules, Kind, Recover);
11696 }
11697
CheckMemberSpecialization(const NamedDecl * D)11698 bool CheckMemberSpecialization(const NamedDecl *D) {
11699 return Kind == Sema::AcceptableKind::Visible
11700 ? S.hasVisibleMemberSpecialization(D)
11701 : S.hasReachableMemberSpecialization(D);
11702 }
11703
CheckExplicitSpecialization(const NamedDecl * D)11704 bool CheckExplicitSpecialization(const NamedDecl *D) {
11705 return Kind == Sema::AcceptableKind::Visible
11706 ? S.hasVisibleExplicitSpecialization(D)
11707 : S.hasReachableExplicitSpecialization(D);
11708 }
11709
CheckDeclaration(const NamedDecl * D)11710 bool CheckDeclaration(const NamedDecl *D) {
11711 return Kind == Sema::AcceptableKind::Visible ? S.hasVisibleDeclaration(D)
11712 : S.hasReachableDeclaration(D);
11713 }
11714
11715 // Check a specific declaration. There are three problematic cases:
11716 //
11717 // 1) The declaration is an explicit specialization of a template
11718 // specialization.
11719 // 2) The declaration is an explicit specialization of a member of an
11720 // templated class.
11721 // 3) The declaration is an instantiation of a template, and that template
11722 // is an explicit specialization of a member of a templated class.
11723 //
11724 // We don't need to go any deeper than that, as the instantiation of the
11725 // surrounding class / etc is not triggered by whatever triggered this
11726 // instantiation, and thus should be checked elsewhere.
11727 template<typename SpecDecl>
checkImpl(SpecDecl * Spec)11728 void checkImpl(SpecDecl *Spec) {
11729 bool IsHiddenExplicitSpecialization = false;
11730 if (Spec->getTemplateSpecializationKind() == TSK_ExplicitSpecialization) {
11731 IsHiddenExplicitSpecialization = Spec->getMemberSpecializationInfo()
11732 ? !CheckMemberSpecialization(Spec)
11733 : !CheckExplicitSpecialization(Spec);
11734 } else {
11735 checkInstantiated(Spec);
11736 }
11737
11738 if (IsHiddenExplicitSpecialization)
11739 diagnose(Spec->getMostRecentDecl(), false);
11740 }
11741
checkInstantiated(FunctionDecl * FD)11742 void checkInstantiated(FunctionDecl *FD) {
11743 if (auto *TD = FD->getPrimaryTemplate())
11744 checkTemplate(TD);
11745 }
11746
checkInstantiated(CXXRecordDecl * RD)11747 void checkInstantiated(CXXRecordDecl *RD) {
11748 auto *SD = dyn_cast<ClassTemplateSpecializationDecl>(RD);
11749 if (!SD)
11750 return;
11751
11752 auto From = SD->getSpecializedTemplateOrPartial();
11753 if (auto *TD = From.dyn_cast<ClassTemplateDecl *>())
11754 checkTemplate(TD);
11755 else if (auto *TD =
11756 From.dyn_cast<ClassTemplatePartialSpecializationDecl *>()) {
11757 if (!CheckDeclaration(TD))
11758 diagnose(TD, true);
11759 checkTemplate(TD);
11760 }
11761 }
11762
checkInstantiated(VarDecl * RD)11763 void checkInstantiated(VarDecl *RD) {
11764 auto *SD = dyn_cast<VarTemplateSpecializationDecl>(RD);
11765 if (!SD)
11766 return;
11767
11768 auto From = SD->getSpecializedTemplateOrPartial();
11769 if (auto *TD = From.dyn_cast<VarTemplateDecl *>())
11770 checkTemplate(TD);
11771 else if (auto *TD =
11772 From.dyn_cast<VarTemplatePartialSpecializationDecl *>()) {
11773 if (!CheckDeclaration(TD))
11774 diagnose(TD, true);
11775 checkTemplate(TD);
11776 }
11777 }
11778
checkInstantiated(EnumDecl * FD)11779 void checkInstantiated(EnumDecl *FD) {}
11780
11781 template<typename TemplDecl>
checkTemplate(TemplDecl * TD)11782 void checkTemplate(TemplDecl *TD) {
11783 if (TD->isMemberSpecialization()) {
11784 if (!CheckMemberSpecialization(TD))
11785 diagnose(TD->getMostRecentDecl(), false);
11786 }
11787 }
11788 };
11789 } // end anonymous namespace
11790
checkSpecializationVisibility(SourceLocation Loc,NamedDecl * Spec)11791 void Sema::checkSpecializationVisibility(SourceLocation Loc, NamedDecl *Spec) {
11792 if (!getLangOpts().Modules)
11793 return;
11794
11795 ExplicitSpecializationVisibilityChecker(*this, Loc,
11796 Sema::AcceptableKind::Visible)
11797 .check(Spec);
11798 }
11799
checkSpecializationReachability(SourceLocation Loc,NamedDecl * Spec)11800 void Sema::checkSpecializationReachability(SourceLocation Loc,
11801 NamedDecl *Spec) {
11802 if (!getLangOpts().CPlusPlusModules)
11803 return checkSpecializationVisibility(Loc, Spec);
11804
11805 ExplicitSpecializationVisibilityChecker(*this, Loc,
11806 Sema::AcceptableKind::Reachable)
11807 .check(Spec);
11808 }
11809
11810 /// Returns the top most location responsible for the definition of \p N.
11811 /// If \p N is a a template specialization, this is the location
11812 /// of the top of the instantiation stack.
11813 /// Otherwise, the location of \p N is returned.
getTopMostPointOfInstantiation(const NamedDecl * N) const11814 SourceLocation Sema::getTopMostPointOfInstantiation(const NamedDecl *N) const {
11815 if (!getLangOpts().CPlusPlus || CodeSynthesisContexts.empty())
11816 return N->getLocation();
11817 if (const auto *FD = dyn_cast<FunctionDecl>(N)) {
11818 if (!FD->isFunctionTemplateSpecialization())
11819 return FD->getLocation();
11820 } else if (!isa<ClassTemplateSpecializationDecl,
11821 VarTemplateSpecializationDecl>(N)) {
11822 return N->getLocation();
11823 }
11824 for (const CodeSynthesisContext &CSC : CodeSynthesisContexts) {
11825 if (!CSC.isInstantiationRecord() || CSC.PointOfInstantiation.isInvalid())
11826 continue;
11827 return CSC.PointOfInstantiation;
11828 }
11829 return N->getLocation();
11830 }
11831