1 //===--- SemaCXXScopeSpec.cpp - Semantic Analysis for C++ scope specifiers-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements C++ semantic analysis for scope specifiers.
12 //===----------------------------------------------------------------------===//
14 #include "TypeLocBuilder.h"
15 #include "clang/AST/ASTContext.h"
16 #include "clang/AST/DeclTemplate.h"
17 #include "clang/AST/ExprCXX.h"
18 #include "clang/AST/NestedNameSpecifier.h"
19 #include "clang/Basic/PartialDiagnostic.h"
20 #include "clang/Sema/DeclSpec.h"
21 #include "clang/Sema/Lookup.h"
22 #include "clang/Sema/SemaInternal.h"
23 #include "clang/Sema/Template.h"
24 #include "llvm/ADT/STLExtras.h"
25 using namespace clang;
27 /// \brief Find the current instantiation that associated with the given type.
28 static CXXRecordDecl *getCurrentInstantiationOf(QualType T,
29 DeclContext *CurContext) {
33 const Type *Ty = T->getCanonicalTypeInternal().getTypePtr();
34 if (const RecordType *RecordTy = dyn_cast<RecordType>(Ty)) {
35 CXXRecordDecl *Record = cast<CXXRecordDecl>(RecordTy->getDecl());
36 if (!Record->isDependentContext() ||
37 Record->isCurrentInstantiation(CurContext))
41 } else if (isa<InjectedClassNameType>(Ty))
42 return cast<InjectedClassNameType>(Ty)->getDecl();
47 /// \brief Compute the DeclContext that is associated with the given type.
49 /// \param T the type for which we are attempting to find a DeclContext.
51 /// \returns the declaration context represented by the type T,
52 /// or NULL if the declaration context cannot be computed (e.g., because it is
53 /// dependent and not the current instantiation).
54 DeclContext *Sema::computeDeclContext(QualType T) {
55 if (!T->isDependentType())
56 if (const TagType *Tag = T->getAs<TagType>())
57 return Tag->getDecl();
59 return ::getCurrentInstantiationOf(T, CurContext);
62 /// \brief Compute the DeclContext that is associated with the given
65 /// \param SS the C++ scope specifier as it appears in the source
67 /// \param EnteringContext when true, we will be entering the context of
68 /// this scope specifier, so we can retrieve the declaration context of a
69 /// class template or class template partial specialization even if it is
70 /// not the current instantiation.
72 /// \returns the declaration context represented by the scope specifier @p SS,
73 /// or NULL if the declaration context cannot be computed (e.g., because it is
74 /// dependent and not the current instantiation).
75 DeclContext *Sema::computeDeclContext(const CXXScopeSpec &SS,
76 bool EnteringContext) {
77 if (!SS.isSet() || SS.isInvalid())
80 NestedNameSpecifier *NNS = SS.getScopeRep();
81 if (NNS->isDependent()) {
82 // If this nested-name-specifier refers to the current
83 // instantiation, return its DeclContext.
84 if (CXXRecordDecl *Record = getCurrentInstantiationOf(NNS))
87 if (EnteringContext) {
88 const Type *NNSType = NNS->getAsType();
93 // Look through type alias templates, per C++0x [temp.dep.type]p1.
94 NNSType = Context.getCanonicalType(NNSType);
95 if (const TemplateSpecializationType *SpecType
96 = NNSType->getAs<TemplateSpecializationType>()) {
97 // We are entering the context of the nested name specifier, so try to
98 // match the nested name specifier to either a primary class template
99 // or a class template partial specialization.
100 if (ClassTemplateDecl *ClassTemplate
101 = dyn_cast_or_null<ClassTemplateDecl>(
102 SpecType->getTemplateName().getAsTemplateDecl())) {
104 = Context.getCanonicalType(QualType(SpecType, 0));
106 // If the type of the nested name specifier is the same as the
107 // injected class name of the named class template, we're entering
108 // into that class template definition.
110 = ClassTemplate->getInjectedClassNameSpecialization();
111 if (Context.hasSameType(Injected, ContextType))
112 return ClassTemplate->getTemplatedDecl();
114 // If the type of the nested name specifier is the same as the
115 // type of one of the class template's class template partial
116 // specializations, we're entering into the definition of that
117 // class template partial specialization.
118 if (ClassTemplatePartialSpecializationDecl *PartialSpec
119 = ClassTemplate->findPartialSpecialization(ContextType)) {
120 // A declaration of the partial specialization must be visible.
121 // We can always recover here, because this only happens when we're
122 // entering the context, and that can't happen in a SFINAE context.
123 assert(!isSFINAEContext() &&
124 "partial specialization scope specifier in SFINAE context?");
125 if (!hasVisibleDeclaration(PartialSpec))
126 diagnoseMissingImport(SS.getLastQualifierNameLoc(), PartialSpec,
127 MissingImportKind::PartialSpecialization,
132 } else if (const RecordType *RecordT = NNSType->getAs<RecordType>()) {
133 // The nested name specifier refers to a member of a class template.
134 return RecordT->getDecl();
141 switch (NNS->getKind()) {
142 case NestedNameSpecifier::Identifier:
143 llvm_unreachable("Dependent nested-name-specifier has no DeclContext");
145 case NestedNameSpecifier::Namespace:
146 return NNS->getAsNamespace();
148 case NestedNameSpecifier::NamespaceAlias:
149 return NNS->getAsNamespaceAlias()->getNamespace();
151 case NestedNameSpecifier::TypeSpec:
152 case NestedNameSpecifier::TypeSpecWithTemplate: {
153 const TagType *Tag = NNS->getAsType()->getAs<TagType>();
154 assert(Tag && "Non-tag type in nested-name-specifier");
155 return Tag->getDecl();
158 case NestedNameSpecifier::Global:
159 return Context.getTranslationUnitDecl();
161 case NestedNameSpecifier::Super:
162 return NNS->getAsRecordDecl();
165 llvm_unreachable("Invalid NestedNameSpecifier::Kind!");
168 bool Sema::isDependentScopeSpecifier(const CXXScopeSpec &SS) {
169 if (!SS.isSet() || SS.isInvalid())
172 return SS.getScopeRep()->isDependent();
175 /// \brief If the given nested name specifier refers to the current
176 /// instantiation, return the declaration that corresponds to that
177 /// current instantiation (C++0x [temp.dep.type]p1).
179 /// \param NNS a dependent nested name specifier.
180 CXXRecordDecl *Sema::getCurrentInstantiationOf(NestedNameSpecifier *NNS) {
181 assert(getLangOpts().CPlusPlus && "Only callable in C++");
182 assert(NNS->isDependent() && "Only dependent nested-name-specifier allowed");
184 if (!NNS->getAsType())
187 QualType T = QualType(NNS->getAsType(), 0);
188 return ::getCurrentInstantiationOf(T, CurContext);
191 /// \brief Require that the context specified by SS be complete.
193 /// If SS refers to a type, this routine checks whether the type is
194 /// complete enough (or can be made complete enough) for name lookup
195 /// into the DeclContext. A type that is not yet completed can be
196 /// considered "complete enough" if it is a class/struct/union/enum
197 /// that is currently being defined. Or, if we have a type that names
198 /// a class template specialization that is not a complete type, we
199 /// will attempt to instantiate that class template.
200 bool Sema::RequireCompleteDeclContext(CXXScopeSpec &SS,
202 assert(DC && "given null context");
204 TagDecl *tag = dyn_cast<TagDecl>(DC);
206 // If this is a dependent type, then we consider it complete.
207 // FIXME: This is wrong; we should require a (visible) definition to
208 // exist in this case too.
209 if (!tag || tag->isDependentContext())
212 // If we're currently defining this type, then lookup into the
213 // type is okay: don't complain that it isn't complete yet.
214 QualType type = Context.getTypeDeclType(tag);
215 const TagType *tagType = type->getAs<TagType>();
216 if (tagType && tagType->isBeingDefined())
219 SourceLocation loc = SS.getLastQualifierNameLoc();
220 if (loc.isInvalid()) loc = SS.getRange().getBegin();
222 // The type must be complete.
223 if (RequireCompleteType(loc, type, diag::err_incomplete_nested_name_spec,
225 SS.SetInvalid(SS.getRange());
229 // Fixed enum types are complete, but they aren't valid as scopes
230 // until we see a definition, so awkwardly pull out this special
232 const EnumType *enumType = dyn_cast_or_null<EnumType>(tagType);
235 if (enumType->getDecl()->isCompleteDefinition()) {
236 // If we know about the definition but it is not visible, complain.
237 NamedDecl *SuggestedDef = nullptr;
238 if (!hasVisibleDefinition(enumType->getDecl(), &SuggestedDef,
239 /*OnlyNeedComplete*/false)) {
240 // If the user is going to see an error here, recover by making the
241 // definition visible.
242 bool TreatAsComplete = !isSFINAEContext();
243 diagnoseMissingImport(loc, SuggestedDef, MissingImportKind::Definition,
244 /*Recover*/TreatAsComplete);
245 return !TreatAsComplete;
250 // Try to instantiate the definition, if this is a specialization of an
251 // enumeration temploid.
252 EnumDecl *ED = enumType->getDecl();
253 if (EnumDecl *Pattern = ED->getInstantiatedFromMemberEnum()) {
254 MemberSpecializationInfo *MSI = ED->getMemberSpecializationInfo();
255 if (MSI->getTemplateSpecializationKind() != TSK_ExplicitSpecialization) {
256 if (InstantiateEnum(loc, ED, Pattern, getTemplateInstantiationArgs(ED),
257 TSK_ImplicitInstantiation)) {
258 SS.SetInvalid(SS.getRange());
265 Diag(loc, diag::err_incomplete_nested_name_spec)
266 << type << SS.getRange();
267 SS.SetInvalid(SS.getRange());
271 bool Sema::ActOnCXXGlobalScopeSpecifier(SourceLocation CCLoc,
273 SS.MakeGlobal(Context, CCLoc);
277 bool Sema::ActOnSuperScopeSpecifier(SourceLocation SuperLoc,
278 SourceLocation ColonColonLoc,
280 CXXRecordDecl *RD = nullptr;
281 for (Scope *S = getCurScope(); S; S = S->getParent()) {
282 if (S->isFunctionScope()) {
283 if (CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(S->getEntity()))
284 RD = MD->getParent();
287 if (S->isClassScope()) {
288 RD = cast<CXXRecordDecl>(S->getEntity());
294 Diag(SuperLoc, diag::err_invalid_super_scope);
296 } else if (RD->isLambda()) {
297 Diag(SuperLoc, diag::err_super_in_lambda_unsupported);
299 } else if (RD->getNumBases() == 0) {
300 Diag(SuperLoc, diag::err_no_base_classes) << RD->getName();
304 SS.MakeSuper(Context, RD, SuperLoc, ColonColonLoc);
308 /// \brief Determines whether the given declaration is an valid acceptable
309 /// result for name lookup of a nested-name-specifier.
310 /// \param SD Declaration checked for nested-name-specifier.
311 /// \param IsExtension If not null and the declaration is accepted as an
312 /// extension, the pointed variable is assigned true.
313 bool Sema::isAcceptableNestedNameSpecifier(const NamedDecl *SD,
318 SD = SD->getUnderlyingDecl();
320 // Namespace and namespace aliases are fine.
321 if (isa<NamespaceDecl>(SD))
324 if (!isa<TypeDecl>(SD))
327 // Determine whether we have a class (or, in C++11, an enum) or
328 // a typedef thereof. If so, build the nested-name-specifier.
329 QualType T = Context.getTypeDeclType(cast<TypeDecl>(SD));
330 if (T->isDependentType())
332 if (const TypedefNameDecl *TD = dyn_cast<TypedefNameDecl>(SD)) {
333 if (TD->getUnderlyingType()->isRecordType())
335 if (TD->getUnderlyingType()->isEnumeralType()) {
336 if (Context.getLangOpts().CPlusPlus11)
341 } else if (isa<RecordDecl>(SD)) {
343 } else if (isa<EnumDecl>(SD)) {
344 if (Context.getLangOpts().CPlusPlus11)
353 /// \brief If the given nested-name-specifier begins with a bare identifier
354 /// (e.g., Base::), perform name lookup for that identifier as a
355 /// nested-name-specifier within the given scope, and return the result of that
357 NamedDecl *Sema::FindFirstQualifierInScope(Scope *S, NestedNameSpecifier *NNS) {
361 while (NNS->getPrefix())
362 NNS = NNS->getPrefix();
364 if (NNS->getKind() != NestedNameSpecifier::Identifier)
367 LookupResult Found(*this, NNS->getAsIdentifier(), SourceLocation(),
368 LookupNestedNameSpecifierName);
369 LookupName(Found, S);
370 assert(!Found.isAmbiguous() && "Cannot handle ambiguities here yet");
372 if (!Found.isSingleResult())
375 NamedDecl *Result = Found.getFoundDecl();
376 if (isAcceptableNestedNameSpecifier(Result))
382 bool Sema::isNonTypeNestedNameSpecifier(Scope *S, CXXScopeSpec &SS,
383 NestedNameSpecInfo &IdInfo) {
384 QualType ObjectType = GetTypeFromParser(IdInfo.ObjectType);
385 LookupResult Found(*this, IdInfo.Identifier, IdInfo.IdentifierLoc,
386 LookupNestedNameSpecifierName);
388 // Determine where to perform name lookup
389 DeclContext *LookupCtx = nullptr;
390 bool isDependent = false;
391 if (!ObjectType.isNull()) {
392 // This nested-name-specifier occurs in a member access expression, e.g.,
393 // x->B::f, and we are looking into the type of the object.
394 assert(!SS.isSet() && "ObjectType and scope specifier cannot coexist");
395 LookupCtx = computeDeclContext(ObjectType);
396 isDependent = ObjectType->isDependentType();
397 } else if (SS.isSet()) {
398 // This nested-name-specifier occurs after another nested-name-specifier,
399 // so long into the context associated with the prior nested-name-specifier.
400 LookupCtx = computeDeclContext(SS, false);
401 isDependent = isDependentScopeSpecifier(SS);
402 Found.setContextRange(SS.getRange());
406 // Perform "qualified" name lookup into the declaration context we
407 // computed, which is either the type of the base of a member access
408 // expression or the declaration context associated with a prior
409 // nested-name-specifier.
411 // The declaration context must be complete.
412 if (!LookupCtx->isDependentContext() &&
413 RequireCompleteDeclContext(SS, LookupCtx))
416 LookupQualifiedName(Found, LookupCtx);
417 } else if (isDependent) {
420 LookupName(Found, S);
422 Found.suppressDiagnostics();
424 return Found.getAsSingle<NamespaceDecl>();
429 // Callback to only accept typo corrections that can be a valid C++ member
430 // intializer: either a non-static field member or a base class.
431 class NestedNameSpecifierValidatorCCC : public CorrectionCandidateCallback {
433 explicit NestedNameSpecifierValidatorCCC(Sema &SRef)
436 bool ValidateCandidate(const TypoCorrection &candidate) override {
437 return SRef.isAcceptableNestedNameSpecifier(candidate.getCorrectionDecl());
446 /// \brief Build a new nested-name-specifier for "identifier::", as described
447 /// by ActOnCXXNestedNameSpecifier.
449 /// \param S Scope in which the nested-name-specifier occurs.
450 /// \param IdInfo Parser information about an identifier in the
451 /// nested-name-spec.
452 /// \param EnteringContext If true, enter the context specified by the
453 /// nested-name-specifier.
454 /// \param SS Optional nested name specifier preceding the identifier.
455 /// \param ScopeLookupResult Provides the result of name lookup within the
456 /// scope of the nested-name-specifier that was computed at template
458 /// \param ErrorRecoveryLookup Specifies if the method is called to improve
459 /// error recovery and what kind of recovery is performed.
460 /// \param IsCorrectedToColon If not null, suggestion of replace '::' -> ':'
461 /// are allowed. The bool value pointed by this parameter is set to
462 /// 'true' if the identifier is treated as if it was followed by ':',
464 /// \param OnlyNamespace If true, only considers namespaces in lookup.
466 /// This routine differs only slightly from ActOnCXXNestedNameSpecifier, in
467 /// that it contains an extra parameter \p ScopeLookupResult, which provides
468 /// the result of name lookup within the scope of the nested-name-specifier
469 /// that was computed at template definition time.
471 /// If ErrorRecoveryLookup is true, then this call is used to improve error
472 /// recovery. This means that it should not emit diagnostics, it should
473 /// just return true on failure. It also means it should only return a valid
474 /// scope if it *knows* that the result is correct. It should not return in a
475 /// dependent context, for example. Nor will it extend \p SS with the scope
477 bool Sema::BuildCXXNestedNameSpecifier(Scope *S, NestedNameSpecInfo &IdInfo,
478 bool EnteringContext, CXXScopeSpec &SS,
479 NamedDecl *ScopeLookupResult,
480 bool ErrorRecoveryLookup,
481 bool *IsCorrectedToColon,
482 bool OnlyNamespace) {
483 if (IdInfo.Identifier->isEditorPlaceholder())
485 LookupResult Found(*this, IdInfo.Identifier, IdInfo.IdentifierLoc,
486 OnlyNamespace ? LookupNamespaceName
487 : LookupNestedNameSpecifierName);
488 QualType ObjectType = GetTypeFromParser(IdInfo.ObjectType);
490 // Determine where to perform name lookup
491 DeclContext *LookupCtx = nullptr;
492 bool isDependent = false;
493 if (IsCorrectedToColon)
494 *IsCorrectedToColon = false;
495 if (!ObjectType.isNull()) {
496 // This nested-name-specifier occurs in a member access expression, e.g.,
497 // x->B::f, and we are looking into the type of the object.
498 assert(!SS.isSet() && "ObjectType and scope specifier cannot coexist");
499 LookupCtx = computeDeclContext(ObjectType);
500 isDependent = ObjectType->isDependentType();
501 } else if (SS.isSet()) {
502 // This nested-name-specifier occurs after another nested-name-specifier,
503 // so look into the context associated with the prior nested-name-specifier.
504 LookupCtx = computeDeclContext(SS, EnteringContext);
505 isDependent = isDependentScopeSpecifier(SS);
506 Found.setContextRange(SS.getRange());
509 bool ObjectTypeSearchedInScope = false;
511 // Perform "qualified" name lookup into the declaration context we
512 // computed, which is either the type of the base of a member access
513 // expression or the declaration context associated with a prior
514 // nested-name-specifier.
516 // The declaration context must be complete.
517 if (!LookupCtx->isDependentContext() &&
518 RequireCompleteDeclContext(SS, LookupCtx))
521 LookupQualifiedName(Found, LookupCtx);
523 if (!ObjectType.isNull() && Found.empty()) {
524 // C++ [basic.lookup.classref]p4:
525 // If the id-expression in a class member access is a qualified-id of
528 // class-name-or-namespace-name::...
530 // the class-name-or-namespace-name following the . or -> operator is
531 // looked up both in the context of the entire postfix-expression and in
532 // the scope of the class of the object expression. If the name is found
533 // only in the scope of the class of the object expression, the name
534 // shall refer to a class-name. If the name is found only in the
535 // context of the entire postfix-expression, the name shall refer to a
536 // class-name or namespace-name. [...]
538 // Qualified name lookup into a class will not find a namespace-name,
539 // so we do not need to diagnose that case specifically. However,
540 // this qualified name lookup may find nothing. In that case, perform
541 // unqualified name lookup in the given scope (if available) or
542 // reconstruct the result from when name lookup was performed at template
545 LookupName(Found, S);
546 else if (ScopeLookupResult)
547 Found.addDecl(ScopeLookupResult);
549 ObjectTypeSearchedInScope = true;
551 } else if (!isDependent) {
552 // Perform unqualified name lookup in the current scope.
553 LookupName(Found, S);
556 if (Found.isAmbiguous())
559 // If we performed lookup into a dependent context and did not find anything,
560 // that's fine: just build a dependent nested-name-specifier.
561 if (Found.empty() && isDependent &&
562 !(LookupCtx && LookupCtx->isRecord() &&
563 (!cast<CXXRecordDecl>(LookupCtx)->hasDefinition() ||
564 !cast<CXXRecordDecl>(LookupCtx)->hasAnyDependentBases()))) {
565 // Don't speculate if we're just trying to improve error recovery.
566 if (ErrorRecoveryLookup)
569 // We were not able to compute the declaration context for a dependent
570 // base object type or prior nested-name-specifier, so this
571 // nested-name-specifier refers to an unknown specialization. Just build
572 // a dependent nested-name-specifier.
573 SS.Extend(Context, IdInfo.Identifier, IdInfo.IdentifierLoc, IdInfo.CCLoc);
577 if (Found.empty() && !ErrorRecoveryLookup) {
578 // If identifier is not found as class-name-or-namespace-name, but is found
579 // as other entity, don't look for typos.
580 LookupResult R(*this, Found.getLookupNameInfo(), LookupOrdinaryName);
582 LookupQualifiedName(R, LookupCtx);
583 else if (S && !isDependent)
586 // Don't diagnose problems with this speculative lookup.
587 R.suppressDiagnostics();
588 // The identifier is found in ordinary lookup. If correction to colon is
589 // allowed, suggest replacement to ':'.
590 if (IsCorrectedToColon) {
591 *IsCorrectedToColon = true;
592 Diag(IdInfo.CCLoc, diag::err_nested_name_spec_is_not_class)
593 << IdInfo.Identifier << getLangOpts().CPlusPlus
594 << FixItHint::CreateReplacement(IdInfo.CCLoc, ":");
595 if (NamedDecl *ND = R.getAsSingle<NamedDecl>())
596 Diag(ND->getLocation(), diag::note_declared_at);
599 // Replacement '::' -> ':' is not allowed, just issue respective error.
600 Diag(R.getNameLoc(), OnlyNamespace
601 ? unsigned(diag::err_expected_namespace_name)
602 : unsigned(diag::err_expected_class_or_namespace))
603 << IdInfo.Identifier << getLangOpts().CPlusPlus;
604 if (NamedDecl *ND = R.getAsSingle<NamedDecl>())
605 Diag(ND->getLocation(), diag::note_entity_declared_at)
606 << IdInfo.Identifier;
611 if (Found.empty() && !ErrorRecoveryLookup && !getLangOpts().MSVCCompat) {
612 // We haven't found anything, and we're not recovering from a
613 // different kind of error, so look for typos.
614 DeclarationName Name = Found.getLookupName();
616 if (TypoCorrection Corrected = CorrectTypo(
617 Found.getLookupNameInfo(), Found.getLookupKind(), S, &SS,
618 llvm::make_unique<NestedNameSpecifierValidatorCCC>(*this),
619 CTK_ErrorRecovery, LookupCtx, EnteringContext)) {
621 bool DroppedSpecifier =
622 Corrected.WillReplaceSpecifier() &&
623 Name.getAsString() == Corrected.getAsString(getLangOpts());
624 if (DroppedSpecifier)
626 diagnoseTypo(Corrected, PDiag(diag::err_no_member_suggest)
627 << Name << LookupCtx << DroppedSpecifier
630 diagnoseTypo(Corrected, PDiag(diag::err_undeclared_var_use_suggest)
633 if (Corrected.getCorrectionSpecifier())
634 SS.MakeTrivial(Context, Corrected.getCorrectionSpecifier(),
635 SourceRange(Found.getNameLoc()));
637 if (NamedDecl *ND = Corrected.getFoundDecl())
639 Found.setLookupName(Corrected.getCorrection());
641 Found.setLookupName(IdInfo.Identifier);
646 Found.isSingleResult() ? Found.getRepresentativeDecl() : nullptr;
647 bool IsExtension = false;
648 bool AcceptSpec = isAcceptableNestedNameSpecifier(SD, &IsExtension);
649 if (!AcceptSpec && IsExtension) {
651 Diag(IdInfo.IdentifierLoc, diag::ext_nested_name_spec_is_enum);
654 if (!ObjectType.isNull() && !ObjectTypeSearchedInScope &&
655 !getLangOpts().CPlusPlus11) {
656 // C++03 [basic.lookup.classref]p4:
657 // [...] If the name is found in both contexts, the
658 // class-name-or-namespace-name shall refer to the same entity.
660 // We already found the name in the scope of the object. Now, look
661 // into the current scope (the scope of the postfix-expression) to
662 // see if we can find the same name there. As above, if there is no
663 // scope, reconstruct the result from the template instantiation itself.
665 // Note that C++11 does *not* perform this redundant lookup.
666 NamedDecl *OuterDecl;
668 LookupResult FoundOuter(*this, IdInfo.Identifier, IdInfo.IdentifierLoc,
669 LookupNestedNameSpecifierName);
670 LookupName(FoundOuter, S);
671 OuterDecl = FoundOuter.getAsSingle<NamedDecl>();
673 OuterDecl = ScopeLookupResult;
675 if (isAcceptableNestedNameSpecifier(OuterDecl) &&
676 OuterDecl->getCanonicalDecl() != SD->getCanonicalDecl() &&
677 (!isa<TypeDecl>(OuterDecl) || !isa<TypeDecl>(SD) ||
678 !Context.hasSameType(
679 Context.getTypeDeclType(cast<TypeDecl>(OuterDecl)),
680 Context.getTypeDeclType(cast<TypeDecl>(SD))))) {
681 if (ErrorRecoveryLookup)
684 Diag(IdInfo.IdentifierLoc,
685 diag::err_nested_name_member_ref_lookup_ambiguous)
686 << IdInfo.Identifier;
687 Diag(SD->getLocation(), diag::note_ambig_member_ref_object_type)
689 Diag(OuterDecl->getLocation(), diag::note_ambig_member_ref_scope);
691 // Fall through so that we'll pick the name we found in the object
692 // type, since that's probably what the user wanted anyway.
696 if (auto *TD = dyn_cast_or_null<TypedefNameDecl>(SD))
697 MarkAnyDeclReferenced(TD->getLocation(), TD, /*OdrUse=*/false);
699 // If we're just performing this lookup for error-recovery purposes,
700 // don't extend the nested-name-specifier. Just return now.
701 if (ErrorRecoveryLookup)
704 // The use of a nested name specifier may trigger deprecation warnings.
705 DiagnoseUseOfDecl(SD, IdInfo.CCLoc);
707 if (NamespaceDecl *Namespace = dyn_cast<NamespaceDecl>(SD)) {
708 SS.Extend(Context, Namespace, IdInfo.IdentifierLoc, IdInfo.CCLoc);
712 if (NamespaceAliasDecl *Alias = dyn_cast<NamespaceAliasDecl>(SD)) {
713 SS.Extend(Context, Alias, IdInfo.IdentifierLoc, IdInfo.CCLoc);
718 Context.getTypeDeclType(cast<TypeDecl>(SD->getUnderlyingDecl()));
720 if (isa<InjectedClassNameType>(T)) {
721 InjectedClassNameTypeLoc InjectedTL
722 = TLB.push<InjectedClassNameTypeLoc>(T);
723 InjectedTL.setNameLoc(IdInfo.IdentifierLoc);
724 } else if (isa<RecordType>(T)) {
725 RecordTypeLoc RecordTL = TLB.push<RecordTypeLoc>(T);
726 RecordTL.setNameLoc(IdInfo.IdentifierLoc);
727 } else if (isa<TypedefType>(T)) {
728 TypedefTypeLoc TypedefTL = TLB.push<TypedefTypeLoc>(T);
729 TypedefTL.setNameLoc(IdInfo.IdentifierLoc);
730 } else if (isa<EnumType>(T)) {
731 EnumTypeLoc EnumTL = TLB.push<EnumTypeLoc>(T);
732 EnumTL.setNameLoc(IdInfo.IdentifierLoc);
733 } else if (isa<TemplateTypeParmType>(T)) {
734 TemplateTypeParmTypeLoc TemplateTypeTL
735 = TLB.push<TemplateTypeParmTypeLoc>(T);
736 TemplateTypeTL.setNameLoc(IdInfo.IdentifierLoc);
737 } else if (isa<UnresolvedUsingType>(T)) {
738 UnresolvedUsingTypeLoc UnresolvedTL
739 = TLB.push<UnresolvedUsingTypeLoc>(T);
740 UnresolvedTL.setNameLoc(IdInfo.IdentifierLoc);
741 } else if (isa<SubstTemplateTypeParmType>(T)) {
742 SubstTemplateTypeParmTypeLoc TL
743 = TLB.push<SubstTemplateTypeParmTypeLoc>(T);
744 TL.setNameLoc(IdInfo.IdentifierLoc);
745 } else if (isa<SubstTemplateTypeParmPackType>(T)) {
746 SubstTemplateTypeParmPackTypeLoc TL
747 = TLB.push<SubstTemplateTypeParmPackTypeLoc>(T);
748 TL.setNameLoc(IdInfo.IdentifierLoc);
750 llvm_unreachable("Unhandled TypeDecl node in nested-name-specifier");
753 if (T->isEnumeralType())
754 Diag(IdInfo.IdentifierLoc, diag::warn_cxx98_compat_enum_nested_name_spec);
756 SS.Extend(Context, SourceLocation(), TLB.getTypeLocInContext(Context, T),
761 // Otherwise, we have an error case. If we don't want diagnostics, just
762 // return an error now.
763 if (ErrorRecoveryLookup)
766 // If we didn't find anything during our lookup, try again with
767 // ordinary name lookup, which can help us produce better error
770 Found.clear(LookupOrdinaryName);
771 LookupName(Found, S);
774 // In Microsoft mode, if we are within a templated function and we can't
775 // resolve Identifier, then extend the SS with Identifier. This will have
776 // the effect of resolving Identifier during template instantiation.
777 // The goal is to be able to resolve a function call whose
778 // nested-name-specifier is located inside a dependent base class.
783 // static void foo2() { }
785 // template <class T> class A { public: typedef C D; };
787 // template <class T> class B : public A<T> {
789 // void foo() { D::foo2(); }
791 if (getLangOpts().MSVCCompat) {
792 DeclContext *DC = LookupCtx ? LookupCtx : CurContext;
793 if (DC->isDependentContext() && DC->isFunctionOrMethod()) {
794 CXXRecordDecl *ContainingClass = dyn_cast<CXXRecordDecl>(DC->getParent());
795 if (ContainingClass && ContainingClass->hasAnyDependentBases()) {
796 Diag(IdInfo.IdentifierLoc,
797 diag::ext_undeclared_unqual_id_with_dependent_base)
798 << IdInfo.Identifier << ContainingClass;
799 SS.Extend(Context, IdInfo.Identifier, IdInfo.IdentifierLoc,
806 if (!Found.empty()) {
807 if (TypeDecl *TD = Found.getAsSingle<TypeDecl>())
808 Diag(IdInfo.IdentifierLoc, diag::err_expected_class_or_namespace)
809 << Context.getTypeDeclType(TD) << getLangOpts().CPlusPlus;
811 Diag(IdInfo.IdentifierLoc, diag::err_expected_class_or_namespace)
812 << IdInfo.Identifier << getLangOpts().CPlusPlus;
813 if (NamedDecl *ND = Found.getAsSingle<NamedDecl>())
814 Diag(ND->getLocation(), diag::note_entity_declared_at)
815 << IdInfo.Identifier;
817 } else if (SS.isSet())
818 Diag(IdInfo.IdentifierLoc, diag::err_no_member) << IdInfo.Identifier
819 << LookupCtx << SS.getRange();
821 Diag(IdInfo.IdentifierLoc, diag::err_undeclared_var_use)
822 << IdInfo.Identifier;
827 bool Sema::ActOnCXXNestedNameSpecifier(Scope *S, NestedNameSpecInfo &IdInfo,
828 bool EnteringContext, CXXScopeSpec &SS,
829 bool ErrorRecoveryLookup,
830 bool *IsCorrectedToColon,
831 bool OnlyNamespace) {
835 return BuildCXXNestedNameSpecifier(S, IdInfo, EnteringContext, SS,
836 /*ScopeLookupResult=*/nullptr, false,
837 IsCorrectedToColon, OnlyNamespace);
840 bool Sema::ActOnCXXNestedNameSpecifierDecltype(CXXScopeSpec &SS,
842 SourceLocation ColonColonLoc) {
843 if (SS.isInvalid() || DS.getTypeSpecType() == DeclSpec::TST_error)
846 assert(DS.getTypeSpecType() == DeclSpec::TST_decltype);
848 QualType T = BuildDecltypeType(DS.getRepAsExpr(), DS.getTypeSpecTypeLoc());
849 if (!T->isDependentType() && !T->getAs<TagType>()) {
850 Diag(DS.getTypeSpecTypeLoc(), diag::err_expected_class_or_namespace)
851 << T << getLangOpts().CPlusPlus;
856 DecltypeTypeLoc DecltypeTL = TLB.push<DecltypeTypeLoc>(T);
857 DecltypeTL.setNameLoc(DS.getTypeSpecTypeLoc());
858 SS.Extend(Context, SourceLocation(), TLB.getTypeLocInContext(Context, T),
863 /// IsInvalidUnlessNestedName - This method is used for error recovery
864 /// purposes to determine whether the specified identifier is only valid as
865 /// a nested name specifier, for example a namespace name. It is
866 /// conservatively correct to always return false from this method.
868 /// The arguments are the same as those passed to ActOnCXXNestedNameSpecifier.
869 bool Sema::IsInvalidUnlessNestedName(Scope *S, CXXScopeSpec &SS,
870 NestedNameSpecInfo &IdInfo,
871 bool EnteringContext) {
875 return !BuildCXXNestedNameSpecifier(S, IdInfo, EnteringContext, SS,
876 /*ScopeLookupResult=*/nullptr, true);
879 bool Sema::ActOnCXXNestedNameSpecifier(Scope *S,
881 SourceLocation TemplateKWLoc,
883 SourceLocation TemplateNameLoc,
884 SourceLocation LAngleLoc,
885 ASTTemplateArgsPtr TemplateArgsIn,
886 SourceLocation RAngleLoc,
887 SourceLocation CCLoc,
888 bool EnteringContext) {
892 // Translate the parser's template argument list in our AST format.
893 TemplateArgumentListInfo TemplateArgs(LAngleLoc, RAngleLoc);
894 translateTemplateArguments(TemplateArgsIn, TemplateArgs);
896 DependentTemplateName *DTN = Template.get().getAsDependentTemplateName();
897 if (DTN && DTN->isIdentifier()) {
898 // Handle a dependent template specialization for which we cannot resolve
899 // the template name.
900 assert(DTN->getQualifier() == SS.getScopeRep());
901 QualType T = Context.getDependentTemplateSpecializationType(ETK_None,
903 DTN->getIdentifier(),
906 // Create source-location information for this type.
907 TypeLocBuilder Builder;
908 DependentTemplateSpecializationTypeLoc SpecTL
909 = Builder.push<DependentTemplateSpecializationTypeLoc>(T);
910 SpecTL.setElaboratedKeywordLoc(SourceLocation());
911 SpecTL.setQualifierLoc(SS.getWithLocInContext(Context));
912 SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
913 SpecTL.setTemplateNameLoc(TemplateNameLoc);
914 SpecTL.setLAngleLoc(LAngleLoc);
915 SpecTL.setRAngleLoc(RAngleLoc);
916 for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I)
917 SpecTL.setArgLocInfo(I, TemplateArgs[I].getLocInfo());
919 SS.Extend(Context, TemplateKWLoc, Builder.getTypeLocInContext(Context, T),
924 TemplateDecl *TD = Template.get().getAsTemplateDecl();
925 if (Template.get().getAsOverloadedTemplate() || DTN ||
926 isa<FunctionTemplateDecl>(TD) || isa<VarTemplateDecl>(TD)) {
927 SourceRange R(TemplateNameLoc, RAngleLoc);
928 if (SS.getRange().isValid())
929 R.setBegin(SS.getRange().getBegin());
931 Diag(CCLoc, diag::err_non_type_template_in_nested_name_specifier)
932 << (TD && isa<VarTemplateDecl>(TD)) << Template.get() << R;
933 NoteAllFoundTemplates(Template.get());
937 // We were able to resolve the template name to an actual template.
938 // Build an appropriate nested-name-specifier.
940 CheckTemplateIdType(Template.get(), TemplateNameLoc, TemplateArgs);
944 // Alias template specializations can produce types which are not valid
945 // nested name specifiers.
946 if (!T->isDependentType() && !T->getAs<TagType>()) {
947 Diag(TemplateNameLoc, diag::err_nested_name_spec_non_tag) << T;
948 NoteAllFoundTemplates(Template.get());
952 // Provide source-location information for the template specialization type.
953 TypeLocBuilder Builder;
954 TemplateSpecializationTypeLoc SpecTL
955 = Builder.push<TemplateSpecializationTypeLoc>(T);
956 SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
957 SpecTL.setTemplateNameLoc(TemplateNameLoc);
958 SpecTL.setLAngleLoc(LAngleLoc);
959 SpecTL.setRAngleLoc(RAngleLoc);
960 for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I)
961 SpecTL.setArgLocInfo(I, TemplateArgs[I].getLocInfo());
964 SS.Extend(Context, TemplateKWLoc, Builder.getTypeLocInContext(Context, T),
970 /// \brief A structure that stores a nested-name-specifier annotation,
971 /// including both the nested-name-specifier
972 struct NestedNameSpecifierAnnotation {
973 NestedNameSpecifier *NNS;
977 void *Sema::SaveNestedNameSpecifierAnnotation(CXXScopeSpec &SS) {
978 if (SS.isEmpty() || SS.isInvalid())
981 void *Mem = Context.Allocate(
982 (sizeof(NestedNameSpecifierAnnotation) + SS.location_size()),
983 alignof(NestedNameSpecifierAnnotation));
984 NestedNameSpecifierAnnotation *Annotation
985 = new (Mem) NestedNameSpecifierAnnotation;
986 Annotation->NNS = SS.getScopeRep();
987 memcpy(Annotation + 1, SS.location_data(), SS.location_size());
991 void Sema::RestoreNestedNameSpecifierAnnotation(void *AnnotationPtr,
992 SourceRange AnnotationRange,
994 if (!AnnotationPtr) {
995 SS.SetInvalid(AnnotationRange);
999 NestedNameSpecifierAnnotation *Annotation
1000 = static_cast<NestedNameSpecifierAnnotation *>(AnnotationPtr);
1001 SS.Adopt(NestedNameSpecifierLoc(Annotation->NNS, Annotation + 1));
1004 bool Sema::ShouldEnterDeclaratorScope(Scope *S, const CXXScopeSpec &SS) {
1005 assert(SS.isSet() && "Parser passed invalid CXXScopeSpec.");
1007 // Don't enter a declarator context when the current context is an Objective-C
1009 if (isa<ObjCContainerDecl>(CurContext) || isa<ObjCMethodDecl>(CurContext))
1012 NestedNameSpecifier *Qualifier = SS.getScopeRep();
1014 // There are only two places a well-formed program may qualify a
1015 // declarator: first, when defining a namespace or class member
1016 // out-of-line, and second, when naming an explicitly-qualified
1017 // friend function. The latter case is governed by
1018 // C++03 [basic.lookup.unqual]p10:
1019 // In a friend declaration naming a member function, a name used
1020 // in the function declarator and not part of a template-argument
1021 // in a template-id is first looked up in the scope of the member
1022 // function's class. If it is not found, or if the name is part of
1023 // a template-argument in a template-id, the look up is as
1024 // described for unqualified names in the definition of the class
1025 // granting friendship.
1026 // i.e. we don't push a scope unless it's a class member.
1028 switch (Qualifier->getKind()) {
1029 case NestedNameSpecifier::Global:
1030 case NestedNameSpecifier::Namespace:
1031 case NestedNameSpecifier::NamespaceAlias:
1032 // These are always namespace scopes. We never want to enter a
1033 // namespace scope from anything but a file context.
1034 return CurContext->getRedeclContext()->isFileContext();
1036 case NestedNameSpecifier::Identifier:
1037 case NestedNameSpecifier::TypeSpec:
1038 case NestedNameSpecifier::TypeSpecWithTemplate:
1039 case NestedNameSpecifier::Super:
1040 // These are never namespace scopes.
1044 llvm_unreachable("Invalid NestedNameSpecifier::Kind!");
1047 /// ActOnCXXEnterDeclaratorScope - Called when a C++ scope specifier (global
1048 /// scope or nested-name-specifier) is parsed, part of a declarator-id.
1049 /// After this method is called, according to [C++ 3.4.3p3], names should be
1050 /// looked up in the declarator-id's scope, until the declarator is parsed and
1051 /// ActOnCXXExitDeclaratorScope is called.
1052 /// The 'SS' should be a non-empty valid CXXScopeSpec.
1053 bool Sema::ActOnCXXEnterDeclaratorScope(Scope *S, CXXScopeSpec &SS) {
1054 assert(SS.isSet() && "Parser passed invalid CXXScopeSpec.");
1056 if (SS.isInvalid()) return true;
1058 DeclContext *DC = computeDeclContext(SS, true);
1059 if (!DC) return true;
1061 // Before we enter a declarator's context, we need to make sure that
1062 // it is a complete declaration context.
1063 if (!DC->isDependentContext() && RequireCompleteDeclContext(SS, DC))
1066 EnterDeclaratorContext(S, DC);
1068 // Rebuild the nested name specifier for the new scope.
1069 if (DC->isDependentContext())
1070 RebuildNestedNameSpecifierInCurrentInstantiation(SS);
1075 /// ActOnCXXExitDeclaratorScope - Called when a declarator that previously
1076 /// invoked ActOnCXXEnterDeclaratorScope(), is finished. 'SS' is the same
1077 /// CXXScopeSpec that was passed to ActOnCXXEnterDeclaratorScope as well.
1078 /// Used to indicate that names should revert to being looked up in the
1080 void Sema::ActOnCXXExitDeclaratorScope(Scope *S, const CXXScopeSpec &SS) {
1081 assert(SS.isSet() && "Parser passed invalid CXXScopeSpec.");
1084 assert(!SS.isInvalid() && computeDeclContext(SS, true) &&
1085 "exiting declarator scope we never really entered");
1086 ExitDeclaratorContext(S);