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 "clang/Sema/SemaInternal.h"
15 #include "TypeLocBuilder.h"
16 #include "clang/AST/ASTContext.h"
17 #include "clang/AST/DeclTemplate.h"
18 #include "clang/AST/ExprCXX.h"
19 #include "clang/AST/NestedNameSpecifier.h"
20 #include "clang/Basic/PartialDiagnostic.h"
21 #include "clang/Sema/DeclSpec.h"
22 #include "clang/Sema/Lookup.h"
23 #include "clang/Sema/Template.h"
24 #include "llvm/ADT/STLExtras.h"
25 #include "llvm/Support/raw_ostream.h"
26 using namespace clang;
28 /// \brief Find the current instantiation that associated with the given type.
29 static CXXRecordDecl *getCurrentInstantiationOf(QualType T,
30 DeclContext *CurContext) {
34 const Type *Ty = T->getCanonicalTypeInternal().getTypePtr();
35 if (const RecordType *RecordTy = dyn_cast<RecordType>(Ty)) {
36 CXXRecordDecl *Record = cast<CXXRecordDecl>(RecordTy->getDecl());
37 if (!Record->isDependentContext() ||
38 Record->isCurrentInstantiation(CurContext))
42 } else if (isa<InjectedClassNameType>(Ty))
43 return cast<InjectedClassNameType>(Ty)->getDecl();
48 /// \brief Compute the DeclContext that is associated with the given type.
50 /// \param T the type for which we are attempting to find a DeclContext.
52 /// \returns the declaration context represented by the type T,
53 /// or NULL if the declaration context cannot be computed (e.g., because it is
54 /// dependent and not the current instantiation).
55 DeclContext *Sema::computeDeclContext(QualType T) {
56 if (!T->isDependentType())
57 if (const TagType *Tag = T->getAs<TagType>())
58 return Tag->getDecl();
60 return ::getCurrentInstantiationOf(T, CurContext);
63 /// \brief Compute the DeclContext that is associated with the given
66 /// \param SS the C++ scope specifier as it appears in the source
68 /// \param EnteringContext when true, we will be entering the context of
69 /// this scope specifier, so we can retrieve the declaration context of a
70 /// class template or class template partial specialization even if it is
71 /// not the current instantiation.
73 /// \returns the declaration context represented by the scope specifier @p SS,
74 /// or NULL if the declaration context cannot be computed (e.g., because it is
75 /// dependent and not the current instantiation).
76 DeclContext *Sema::computeDeclContext(const CXXScopeSpec &SS,
77 bool EnteringContext) {
78 if (!SS.isSet() || SS.isInvalid())
81 NestedNameSpecifier *NNS = SS.getScopeRep();
82 if (NNS->isDependent()) {
83 // If this nested-name-specifier refers to the current
84 // instantiation, return its DeclContext.
85 if (CXXRecordDecl *Record = getCurrentInstantiationOf(NNS))
88 if (EnteringContext) {
89 const Type *NNSType = NNS->getAsType();
94 // Look through type alias templates, per C++0x [temp.dep.type]p1.
95 NNSType = Context.getCanonicalType(NNSType);
96 if (const TemplateSpecializationType *SpecType
97 = NNSType->getAs<TemplateSpecializationType>()) {
98 // We are entering the context of the nested name specifier, so try to
99 // match the nested name specifier to either a primary class template
100 // or a class template partial specialization.
101 if (ClassTemplateDecl *ClassTemplate
102 = dyn_cast_or_null<ClassTemplateDecl>(
103 SpecType->getTemplateName().getAsTemplateDecl())) {
105 = Context.getCanonicalType(QualType(SpecType, 0));
107 // If the type of the nested name specifier is the same as the
108 // injected class name of the named class template, we're entering
109 // into that class template definition.
111 = ClassTemplate->getInjectedClassNameSpecialization();
112 if (Context.hasSameType(Injected, ContextType))
113 return ClassTemplate->getTemplatedDecl();
115 // If the type of the nested name specifier is the same as the
116 // type of one of the class template's class template partial
117 // specializations, we're entering into the definition of that
118 // class template partial specialization.
119 if (ClassTemplatePartialSpecializationDecl *PartialSpec
120 = ClassTemplate->findPartialSpecialization(ContextType))
123 } else if (const RecordType *RecordT = NNSType->getAs<RecordType>()) {
124 // The nested name specifier refers to a member of a class template.
125 return RecordT->getDecl();
132 switch (NNS->getKind()) {
133 case NestedNameSpecifier::Identifier:
134 llvm_unreachable("Dependent nested-name-specifier has no DeclContext");
136 case NestedNameSpecifier::Namespace:
137 return NNS->getAsNamespace();
139 case NestedNameSpecifier::NamespaceAlias:
140 return NNS->getAsNamespaceAlias()->getNamespace();
142 case NestedNameSpecifier::TypeSpec:
143 case NestedNameSpecifier::TypeSpecWithTemplate: {
144 const TagType *Tag = NNS->getAsType()->getAs<TagType>();
145 assert(Tag && "Non-tag type in nested-name-specifier");
146 return Tag->getDecl();
149 case NestedNameSpecifier::Global:
150 return Context.getTranslationUnitDecl();
152 case NestedNameSpecifier::Super:
153 return NNS->getAsRecordDecl();
156 llvm_unreachable("Invalid NestedNameSpecifier::Kind!");
159 bool Sema::isDependentScopeSpecifier(const CXXScopeSpec &SS) {
160 if (!SS.isSet() || SS.isInvalid())
163 return SS.getScopeRep()->isDependent();
166 /// \brief If the given nested name specifier refers to the current
167 /// instantiation, return the declaration that corresponds to that
168 /// current instantiation (C++0x [temp.dep.type]p1).
170 /// \param NNS a dependent nested name specifier.
171 CXXRecordDecl *Sema::getCurrentInstantiationOf(NestedNameSpecifier *NNS) {
172 assert(getLangOpts().CPlusPlus && "Only callable in C++");
173 assert(NNS->isDependent() && "Only dependent nested-name-specifier allowed");
175 if (!NNS->getAsType())
178 QualType T = QualType(NNS->getAsType(), 0);
179 return ::getCurrentInstantiationOf(T, CurContext);
182 /// \brief Require that the context specified by SS be complete.
184 /// If SS refers to a type, this routine checks whether the type is
185 /// complete enough (or can be made complete enough) for name lookup
186 /// into the DeclContext. A type that is not yet completed can be
187 /// considered "complete enough" if it is a class/struct/union/enum
188 /// that is currently being defined. Or, if we have a type that names
189 /// a class template specialization that is not a complete type, we
190 /// will attempt to instantiate that class template.
191 bool Sema::RequireCompleteDeclContext(CXXScopeSpec &SS,
193 assert(DC && "given null context");
195 TagDecl *tag = dyn_cast<TagDecl>(DC);
197 // If this is a dependent type, then we consider it complete.
198 if (!tag || tag->isDependentContext())
201 // If we're currently defining this type, then lookup into the
202 // type is okay: don't complain that it isn't complete yet.
203 QualType type = Context.getTypeDeclType(tag);
204 const TagType *tagType = type->getAs<TagType>();
205 if (tagType && tagType->isBeingDefined())
208 SourceLocation loc = SS.getLastQualifierNameLoc();
209 if (loc.isInvalid()) loc = SS.getRange().getBegin();
211 // The type must be complete.
212 if (RequireCompleteType(loc, type, diag::err_incomplete_nested_name_spec,
214 SS.SetInvalid(SS.getRange());
218 // Fixed enum types are complete, but they aren't valid as scopes
219 // until we see a definition, so awkwardly pull out this special
221 // FIXME: The definition might not be visible; complain if it is not.
222 const EnumType *enumType = dyn_cast_or_null<EnumType>(tagType);
223 if (!enumType || enumType->getDecl()->isCompleteDefinition())
226 // Try to instantiate the definition, if this is a specialization of an
227 // enumeration temploid.
228 EnumDecl *ED = enumType->getDecl();
229 if (EnumDecl *Pattern = ED->getInstantiatedFromMemberEnum()) {
230 MemberSpecializationInfo *MSI = ED->getMemberSpecializationInfo();
231 if (MSI->getTemplateSpecializationKind() != TSK_ExplicitSpecialization) {
232 if (InstantiateEnum(loc, ED, Pattern, getTemplateInstantiationArgs(ED),
233 TSK_ImplicitInstantiation)) {
234 SS.SetInvalid(SS.getRange());
241 Diag(loc, diag::err_incomplete_nested_name_spec)
242 << type << SS.getRange();
243 SS.SetInvalid(SS.getRange());
247 bool Sema::ActOnCXXGlobalScopeSpecifier(SourceLocation CCLoc,
249 SS.MakeGlobal(Context, CCLoc);
253 bool Sema::ActOnSuperScopeSpecifier(SourceLocation SuperLoc,
254 SourceLocation ColonColonLoc,
256 CXXRecordDecl *RD = nullptr;
257 for (Scope *S = getCurScope(); S; S = S->getParent()) {
258 if (S->isFunctionScope()) {
259 if (CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(S->getEntity()))
260 RD = MD->getParent();
263 if (S->isClassScope()) {
264 RD = cast<CXXRecordDecl>(S->getEntity());
270 Diag(SuperLoc, diag::err_invalid_super_scope);
272 } else if (RD->isLambda()) {
273 Diag(SuperLoc, diag::err_super_in_lambda_unsupported);
275 } else if (RD->getNumBases() == 0) {
276 Diag(SuperLoc, diag::err_no_base_classes) << RD->getName();
280 SS.MakeSuper(Context, RD, SuperLoc, ColonColonLoc);
284 /// \brief Determines whether the given declaration is an valid acceptable
285 /// result for name lookup of a nested-name-specifier.
286 /// \param SD Declaration checked for nested-name-specifier.
287 /// \param IsExtension If not null and the declaration is accepted as an
288 /// extension, the pointed variable is assigned true.
289 bool Sema::isAcceptableNestedNameSpecifier(const NamedDecl *SD,
294 SD = SD->getUnderlyingDecl();
296 // Namespace and namespace aliases are fine.
297 if (isa<NamespaceDecl>(SD))
300 if (!isa<TypeDecl>(SD))
303 // Determine whether we have a class (or, in C++11, an enum) or
304 // a typedef thereof. If so, build the nested-name-specifier.
305 QualType T = Context.getTypeDeclType(cast<TypeDecl>(SD));
306 if (T->isDependentType())
308 if (const TypedefNameDecl *TD = dyn_cast<TypedefNameDecl>(SD)) {
309 if (TD->getUnderlyingType()->isRecordType())
311 if (TD->getUnderlyingType()->isEnumeralType()) {
312 if (Context.getLangOpts().CPlusPlus11)
317 } else if (isa<RecordDecl>(SD)) {
319 } else if (isa<EnumDecl>(SD)) {
320 if (Context.getLangOpts().CPlusPlus11)
329 /// \brief If the given nested-name-specifier begins with a bare identifier
330 /// (e.g., Base::), perform name lookup for that identifier as a
331 /// nested-name-specifier within the given scope, and return the result of that
333 NamedDecl *Sema::FindFirstQualifierInScope(Scope *S, NestedNameSpecifier *NNS) {
337 while (NNS->getPrefix())
338 NNS = NNS->getPrefix();
340 if (NNS->getKind() != NestedNameSpecifier::Identifier)
343 LookupResult Found(*this, NNS->getAsIdentifier(), SourceLocation(),
344 LookupNestedNameSpecifierName);
345 LookupName(Found, S);
346 assert(!Found.isAmbiguous() && "Cannot handle ambiguities here yet");
348 if (!Found.isSingleResult())
351 NamedDecl *Result = Found.getFoundDecl();
352 if (isAcceptableNestedNameSpecifier(Result))
358 bool Sema::isNonTypeNestedNameSpecifier(Scope *S, CXXScopeSpec &SS,
359 SourceLocation IdLoc,
361 ParsedType ObjectTypePtr) {
362 QualType ObjectType = GetTypeFromParser(ObjectTypePtr);
363 LookupResult Found(*this, &II, IdLoc, LookupNestedNameSpecifierName);
365 // Determine where to perform name lookup
366 DeclContext *LookupCtx = nullptr;
367 bool isDependent = false;
368 if (!ObjectType.isNull()) {
369 // This nested-name-specifier occurs in a member access expression, e.g.,
370 // x->B::f, and we are looking into the type of the object.
371 assert(!SS.isSet() && "ObjectType and scope specifier cannot coexist");
372 LookupCtx = computeDeclContext(ObjectType);
373 isDependent = ObjectType->isDependentType();
374 } else if (SS.isSet()) {
375 // This nested-name-specifier occurs after another nested-name-specifier,
376 // so long into the context associated with the prior nested-name-specifier.
377 LookupCtx = computeDeclContext(SS, false);
378 isDependent = isDependentScopeSpecifier(SS);
379 Found.setContextRange(SS.getRange());
383 // Perform "qualified" name lookup into the declaration context we
384 // computed, which is either the type of the base of a member access
385 // expression or the declaration context associated with a prior
386 // nested-name-specifier.
388 // The declaration context must be complete.
389 if (!LookupCtx->isDependentContext() &&
390 RequireCompleteDeclContext(SS, LookupCtx))
393 LookupQualifiedName(Found, LookupCtx);
394 } else if (isDependent) {
397 LookupName(Found, S);
399 Found.suppressDiagnostics();
401 return Found.getAsSingle<NamespaceDecl>();
406 // Callback to only accept typo corrections that can be a valid C++ member
407 // intializer: either a non-static field member or a base class.
408 class NestedNameSpecifierValidatorCCC : public CorrectionCandidateCallback {
410 explicit NestedNameSpecifierValidatorCCC(Sema &SRef)
413 bool ValidateCandidate(const TypoCorrection &candidate) override {
414 return SRef.isAcceptableNestedNameSpecifier(candidate.getCorrectionDecl());
423 /// \brief Build a new nested-name-specifier for "identifier::", as described
424 /// by ActOnCXXNestedNameSpecifier.
426 /// \param S Scope in which the nested-name-specifier occurs.
427 /// \param Identifier Identifier in the sequence "identifier" "::".
428 /// \param IdentifierLoc Location of the \p Identifier.
429 /// \param CCLoc Location of "::" following Identifier.
430 /// \param ObjectType Type of postfix expression if the nested-name-specifier
431 /// occurs in construct like: <tt>ptr->nns::f</tt>.
432 /// \param EnteringContext If true, enter the context specified by the
433 /// nested-name-specifier.
434 /// \param SS Optional nested name specifier preceding the identifier.
435 /// \param ScopeLookupResult Provides the result of name lookup within the
436 /// scope of the nested-name-specifier that was computed at template
438 /// \param ErrorRecoveryLookup Specifies if the method is called to improve
439 /// error recovery and what kind of recovery is performed.
440 /// \param IsCorrectedToColon If not null, suggestion of replace '::' -> ':'
441 /// are allowed. The bool value pointed by this parameter is set to
442 /// 'true' if the identifier is treated as if it was followed by ':',
445 /// This routine differs only slightly from ActOnCXXNestedNameSpecifier, in
446 /// that it contains an extra parameter \p ScopeLookupResult, which provides
447 /// the result of name lookup within the scope of the nested-name-specifier
448 /// that was computed at template definition time.
450 /// If ErrorRecoveryLookup is true, then this call is used to improve error
451 /// recovery. This means that it should not emit diagnostics, it should
452 /// just return true on failure. It also means it should only return a valid
453 /// scope if it *knows* that the result is correct. It should not return in a
454 /// dependent context, for example. Nor will it extend \p SS with the scope
456 bool Sema::BuildCXXNestedNameSpecifier(Scope *S,
457 IdentifierInfo &Identifier,
458 SourceLocation IdentifierLoc,
459 SourceLocation CCLoc,
461 bool EnteringContext,
463 NamedDecl *ScopeLookupResult,
464 bool ErrorRecoveryLookup,
465 bool *IsCorrectedToColon) {
466 LookupResult Found(*this, &Identifier, IdentifierLoc,
467 LookupNestedNameSpecifierName);
469 // Determine where to perform name lookup
470 DeclContext *LookupCtx = nullptr;
471 bool isDependent = false;
472 if (IsCorrectedToColon)
473 *IsCorrectedToColon = false;
474 if (!ObjectType.isNull()) {
475 // This nested-name-specifier occurs in a member access expression, e.g.,
476 // x->B::f, and we are looking into the type of the object.
477 assert(!SS.isSet() && "ObjectType and scope specifier cannot coexist");
478 LookupCtx = computeDeclContext(ObjectType);
479 isDependent = ObjectType->isDependentType();
480 } else if (SS.isSet()) {
481 // This nested-name-specifier occurs after another nested-name-specifier,
482 // so look into the context associated with the prior nested-name-specifier.
483 LookupCtx = computeDeclContext(SS, EnteringContext);
484 isDependent = isDependentScopeSpecifier(SS);
485 Found.setContextRange(SS.getRange());
488 bool ObjectTypeSearchedInScope = false;
490 // Perform "qualified" name lookup into the declaration context we
491 // computed, which is either the type of the base of a member access
492 // expression or the declaration context associated with a prior
493 // nested-name-specifier.
495 // The declaration context must be complete.
496 if (!LookupCtx->isDependentContext() &&
497 RequireCompleteDeclContext(SS, LookupCtx))
500 LookupQualifiedName(Found, LookupCtx);
502 if (!ObjectType.isNull() && Found.empty()) {
503 // C++ [basic.lookup.classref]p4:
504 // If the id-expression in a class member access is a qualified-id of
507 // class-name-or-namespace-name::...
509 // the class-name-or-namespace-name following the . or -> operator is
510 // looked up both in the context of the entire postfix-expression and in
511 // the scope of the class of the object expression. If the name is found
512 // only in the scope of the class of the object expression, the name
513 // shall refer to a class-name. If the name is found only in the
514 // context of the entire postfix-expression, the name shall refer to a
515 // class-name or namespace-name. [...]
517 // Qualified name lookup into a class will not find a namespace-name,
518 // so we do not need to diagnose that case specifically. However,
519 // this qualified name lookup may find nothing. In that case, perform
520 // unqualified name lookup in the given scope (if available) or
521 // reconstruct the result from when name lookup was performed at template
524 LookupName(Found, S);
525 else if (ScopeLookupResult)
526 Found.addDecl(ScopeLookupResult);
528 ObjectTypeSearchedInScope = true;
530 } else if (!isDependent) {
531 // Perform unqualified name lookup in the current scope.
532 LookupName(Found, S);
535 if (Found.isAmbiguous())
538 // If we performed lookup into a dependent context and did not find anything,
539 // that's fine: just build a dependent nested-name-specifier.
540 if (Found.empty() && isDependent &&
541 !(LookupCtx && LookupCtx->isRecord() &&
542 (!cast<CXXRecordDecl>(LookupCtx)->hasDefinition() ||
543 !cast<CXXRecordDecl>(LookupCtx)->hasAnyDependentBases()))) {
544 // Don't speculate if we're just trying to improve error recovery.
545 if (ErrorRecoveryLookup)
548 // We were not able to compute the declaration context for a dependent
549 // base object type or prior nested-name-specifier, so this
550 // nested-name-specifier refers to an unknown specialization. Just build
551 // a dependent nested-name-specifier.
552 SS.Extend(Context, &Identifier, IdentifierLoc, CCLoc);
556 if (Found.empty() && !ErrorRecoveryLookup) {
557 // If identifier is not found as class-name-or-namespace-name, but is found
558 // as other entity, don't look for typos.
559 LookupResult R(*this, Found.getLookupNameInfo(), LookupOrdinaryName);
561 LookupQualifiedName(R, LookupCtx);
562 else if (S && !isDependent)
565 // Don't diagnose problems with this speculative lookup.
566 R.suppressDiagnostics();
567 // The identifier is found in ordinary lookup. If correction to colon is
568 // allowed, suggest replacement to ':'.
569 if (IsCorrectedToColon) {
570 *IsCorrectedToColon = true;
571 Diag(CCLoc, diag::err_nested_name_spec_is_not_class)
572 << &Identifier << getLangOpts().CPlusPlus
573 << FixItHint::CreateReplacement(CCLoc, ":");
574 if (NamedDecl *ND = R.getAsSingle<NamedDecl>())
575 Diag(ND->getLocation(), diag::note_declared_at);
578 // Replacement '::' -> ':' is not allowed, just issue respective error.
579 Diag(R.getNameLoc(), diag::err_expected_class_or_namespace)
580 << &Identifier << getLangOpts().CPlusPlus;
581 if (NamedDecl *ND = R.getAsSingle<NamedDecl>())
582 Diag(ND->getLocation(), diag::note_entity_declared_at) << &Identifier;
587 if (Found.empty() && !ErrorRecoveryLookup && !getLangOpts().MSVCCompat) {
588 // We haven't found anything, and we're not recovering from a
589 // different kind of error, so look for typos.
590 DeclarationName Name = Found.getLookupName();
592 if (TypoCorrection Corrected = CorrectTypo(
593 Found.getLookupNameInfo(), Found.getLookupKind(), S, &SS,
594 llvm::make_unique<NestedNameSpecifierValidatorCCC>(*this),
595 CTK_ErrorRecovery, LookupCtx, EnteringContext)) {
597 bool DroppedSpecifier =
598 Corrected.WillReplaceSpecifier() &&
599 Name.getAsString() == Corrected.getAsString(getLangOpts());
600 if (DroppedSpecifier)
602 diagnoseTypo(Corrected, PDiag(diag::err_no_member_suggest)
603 << Name << LookupCtx << DroppedSpecifier
606 diagnoseTypo(Corrected, PDiag(diag::err_undeclared_var_use_suggest)
609 if (NamedDecl *ND = Corrected.getFoundDecl())
611 Found.setLookupName(Corrected.getCorrection());
613 Found.setLookupName(&Identifier);
618 Found.isSingleResult() ? Found.getRepresentativeDecl() : nullptr;
619 bool IsExtension = false;
620 bool AcceptSpec = isAcceptableNestedNameSpecifier(SD, &IsExtension);
621 if (!AcceptSpec && IsExtension) {
623 Diag(IdentifierLoc, diag::ext_nested_name_spec_is_enum);
626 if (!ObjectType.isNull() && !ObjectTypeSearchedInScope &&
627 !getLangOpts().CPlusPlus11) {
628 // C++03 [basic.lookup.classref]p4:
629 // [...] If the name is found in both contexts, the
630 // class-name-or-namespace-name shall refer to the same entity.
632 // We already found the name in the scope of the object. Now, look
633 // into the current scope (the scope of the postfix-expression) to
634 // see if we can find the same name there. As above, if there is no
635 // scope, reconstruct the result from the template instantiation itself.
637 // Note that C++11 does *not* perform this redundant lookup.
638 NamedDecl *OuterDecl;
640 LookupResult FoundOuter(*this, &Identifier, IdentifierLoc,
641 LookupNestedNameSpecifierName);
642 LookupName(FoundOuter, S);
643 OuterDecl = FoundOuter.getAsSingle<NamedDecl>();
645 OuterDecl = ScopeLookupResult;
647 if (isAcceptableNestedNameSpecifier(OuterDecl) &&
648 OuterDecl->getCanonicalDecl() != SD->getCanonicalDecl() &&
649 (!isa<TypeDecl>(OuterDecl) || !isa<TypeDecl>(SD) ||
650 !Context.hasSameType(
651 Context.getTypeDeclType(cast<TypeDecl>(OuterDecl)),
652 Context.getTypeDeclType(cast<TypeDecl>(SD))))) {
653 if (ErrorRecoveryLookup)
657 diag::err_nested_name_member_ref_lookup_ambiguous)
659 Diag(SD->getLocation(), diag::note_ambig_member_ref_object_type)
661 Diag(OuterDecl->getLocation(), diag::note_ambig_member_ref_scope);
663 // Fall through so that we'll pick the name we found in the object
664 // type, since that's probably what the user wanted anyway.
668 if (auto *TD = dyn_cast_or_null<TypedefNameDecl>(SD))
669 MarkAnyDeclReferenced(TD->getLocation(), TD, /*OdrUse=*/false);
671 // If we're just performing this lookup for error-recovery purposes,
672 // don't extend the nested-name-specifier. Just return now.
673 if (ErrorRecoveryLookup)
676 // The use of a nested name specifier may trigger deprecation warnings.
677 DiagnoseUseOfDecl(SD, CCLoc);
680 if (NamespaceDecl *Namespace = dyn_cast<NamespaceDecl>(SD)) {
681 SS.Extend(Context, Namespace, IdentifierLoc, CCLoc);
685 if (NamespaceAliasDecl *Alias = dyn_cast<NamespaceAliasDecl>(SD)) {
686 SS.Extend(Context, Alias, IdentifierLoc, CCLoc);
691 Context.getTypeDeclType(cast<TypeDecl>(SD->getUnderlyingDecl()));
693 if (isa<InjectedClassNameType>(T)) {
694 InjectedClassNameTypeLoc InjectedTL
695 = TLB.push<InjectedClassNameTypeLoc>(T);
696 InjectedTL.setNameLoc(IdentifierLoc);
697 } else if (isa<RecordType>(T)) {
698 RecordTypeLoc RecordTL = TLB.push<RecordTypeLoc>(T);
699 RecordTL.setNameLoc(IdentifierLoc);
700 } else if (isa<TypedefType>(T)) {
701 TypedefTypeLoc TypedefTL = TLB.push<TypedefTypeLoc>(T);
702 TypedefTL.setNameLoc(IdentifierLoc);
703 } else if (isa<EnumType>(T)) {
704 EnumTypeLoc EnumTL = TLB.push<EnumTypeLoc>(T);
705 EnumTL.setNameLoc(IdentifierLoc);
706 } else if (isa<TemplateTypeParmType>(T)) {
707 TemplateTypeParmTypeLoc TemplateTypeTL
708 = TLB.push<TemplateTypeParmTypeLoc>(T);
709 TemplateTypeTL.setNameLoc(IdentifierLoc);
710 } else if (isa<UnresolvedUsingType>(T)) {
711 UnresolvedUsingTypeLoc UnresolvedTL
712 = TLB.push<UnresolvedUsingTypeLoc>(T);
713 UnresolvedTL.setNameLoc(IdentifierLoc);
714 } else if (isa<SubstTemplateTypeParmType>(T)) {
715 SubstTemplateTypeParmTypeLoc TL
716 = TLB.push<SubstTemplateTypeParmTypeLoc>(T);
717 TL.setNameLoc(IdentifierLoc);
718 } else if (isa<SubstTemplateTypeParmPackType>(T)) {
719 SubstTemplateTypeParmPackTypeLoc TL
720 = TLB.push<SubstTemplateTypeParmPackTypeLoc>(T);
721 TL.setNameLoc(IdentifierLoc);
723 llvm_unreachable("Unhandled TypeDecl node in nested-name-specifier");
726 if (T->isEnumeralType())
727 Diag(IdentifierLoc, diag::warn_cxx98_compat_enum_nested_name_spec);
729 SS.Extend(Context, SourceLocation(), TLB.getTypeLocInContext(Context, T),
734 // Otherwise, we have an error case. If we don't want diagnostics, just
735 // return an error now.
736 if (ErrorRecoveryLookup)
739 // If we didn't find anything during our lookup, try again with
740 // ordinary name lookup, which can help us produce better error
743 Found.clear(LookupOrdinaryName);
744 LookupName(Found, S);
747 // In Microsoft mode, if we are within a templated function and we can't
748 // resolve Identifier, then extend the SS with Identifier. This will have
749 // the effect of resolving Identifier during template instantiation.
750 // The goal is to be able to resolve a function call whose
751 // nested-name-specifier is located inside a dependent base class.
756 // static void foo2() { }
758 // template <class T> class A { public: typedef C D; };
760 // template <class T> class B : public A<T> {
762 // void foo() { D::foo2(); }
764 if (getLangOpts().MSVCCompat) {
765 DeclContext *DC = LookupCtx ? LookupCtx : CurContext;
766 if (DC->isDependentContext() && DC->isFunctionOrMethod()) {
767 CXXRecordDecl *ContainingClass = dyn_cast<CXXRecordDecl>(DC->getParent());
768 if (ContainingClass && ContainingClass->hasAnyDependentBases()) {
769 Diag(IdentifierLoc, diag::ext_undeclared_unqual_id_with_dependent_base)
770 << &Identifier << ContainingClass;
771 SS.Extend(Context, &Identifier, IdentifierLoc, CCLoc);
777 if (!Found.empty()) {
778 if (TypeDecl *TD = Found.getAsSingle<TypeDecl>())
779 Diag(IdentifierLoc, diag::err_expected_class_or_namespace)
780 << QualType(TD->getTypeForDecl(), 0) << getLangOpts().CPlusPlus;
782 Diag(IdentifierLoc, diag::err_expected_class_or_namespace)
783 << &Identifier << getLangOpts().CPlusPlus;
784 if (NamedDecl *ND = Found.getAsSingle<NamedDecl>())
785 Diag(ND->getLocation(), diag::note_entity_declared_at) << &Identifier;
787 } else if (SS.isSet())
788 Diag(IdentifierLoc, diag::err_no_member) << &Identifier << LookupCtx
791 Diag(IdentifierLoc, diag::err_undeclared_var_use) << &Identifier;
796 bool Sema::ActOnCXXNestedNameSpecifier(Scope *S,
797 IdentifierInfo &Identifier,
798 SourceLocation IdentifierLoc,
799 SourceLocation CCLoc,
800 ParsedType ObjectType,
801 bool EnteringContext,
803 bool ErrorRecoveryLookup,
804 bool *IsCorrectedToColon) {
808 return BuildCXXNestedNameSpecifier(S, Identifier, IdentifierLoc, CCLoc,
809 GetTypeFromParser(ObjectType),
811 /*ScopeLookupResult=*/nullptr, false,
815 bool Sema::ActOnCXXNestedNameSpecifierDecltype(CXXScopeSpec &SS,
817 SourceLocation ColonColonLoc) {
818 if (SS.isInvalid() || DS.getTypeSpecType() == DeclSpec::TST_error)
821 assert(DS.getTypeSpecType() == DeclSpec::TST_decltype);
823 QualType T = BuildDecltypeType(DS.getRepAsExpr(), DS.getTypeSpecTypeLoc());
824 if (!T->isDependentType() && !T->getAs<TagType>()) {
825 Diag(DS.getTypeSpecTypeLoc(), diag::err_expected_class_or_namespace)
826 << T << getLangOpts().CPlusPlus;
831 DecltypeTypeLoc DecltypeTL = TLB.push<DecltypeTypeLoc>(T);
832 DecltypeTL.setNameLoc(DS.getTypeSpecTypeLoc());
833 SS.Extend(Context, SourceLocation(), TLB.getTypeLocInContext(Context, T),
838 /// IsInvalidUnlessNestedName - This method is used for error recovery
839 /// purposes to determine whether the specified identifier is only valid as
840 /// a nested name specifier, for example a namespace name. It is
841 /// conservatively correct to always return false from this method.
843 /// The arguments are the same as those passed to ActOnCXXNestedNameSpecifier.
844 bool Sema::IsInvalidUnlessNestedName(Scope *S, CXXScopeSpec &SS,
845 IdentifierInfo &Identifier,
846 SourceLocation IdentifierLoc,
847 SourceLocation ColonLoc,
848 ParsedType ObjectType,
849 bool EnteringContext) {
853 return !BuildCXXNestedNameSpecifier(S, Identifier, IdentifierLoc, ColonLoc,
854 GetTypeFromParser(ObjectType),
856 /*ScopeLookupResult=*/nullptr, true);
859 bool Sema::ActOnCXXNestedNameSpecifier(Scope *S,
861 SourceLocation TemplateKWLoc,
863 SourceLocation TemplateNameLoc,
864 SourceLocation LAngleLoc,
865 ASTTemplateArgsPtr TemplateArgsIn,
866 SourceLocation RAngleLoc,
867 SourceLocation CCLoc,
868 bool EnteringContext) {
872 // Translate the parser's template argument list in our AST format.
873 TemplateArgumentListInfo TemplateArgs(LAngleLoc, RAngleLoc);
874 translateTemplateArguments(TemplateArgsIn, TemplateArgs);
876 DependentTemplateName *DTN = Template.get().getAsDependentTemplateName();
877 if (DTN && DTN->isIdentifier()) {
878 // Handle a dependent template specialization for which we cannot resolve
879 // the template name.
880 assert(DTN->getQualifier() == SS.getScopeRep());
881 QualType T = Context.getDependentTemplateSpecializationType(ETK_None,
883 DTN->getIdentifier(),
886 // Create source-location information for this type.
887 TypeLocBuilder Builder;
888 DependentTemplateSpecializationTypeLoc SpecTL
889 = Builder.push<DependentTemplateSpecializationTypeLoc>(T);
890 SpecTL.setElaboratedKeywordLoc(SourceLocation());
891 SpecTL.setQualifierLoc(SS.getWithLocInContext(Context));
892 SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
893 SpecTL.setTemplateNameLoc(TemplateNameLoc);
894 SpecTL.setLAngleLoc(LAngleLoc);
895 SpecTL.setRAngleLoc(RAngleLoc);
896 for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I)
897 SpecTL.setArgLocInfo(I, TemplateArgs[I].getLocInfo());
899 SS.Extend(Context, TemplateKWLoc, Builder.getTypeLocInContext(Context, T),
904 TemplateDecl *TD = Template.get().getAsTemplateDecl();
905 if (Template.get().getAsOverloadedTemplate() || DTN ||
906 isa<FunctionTemplateDecl>(TD) || isa<VarTemplateDecl>(TD)) {
907 SourceRange R(TemplateNameLoc, RAngleLoc);
908 if (SS.getRange().isValid())
909 R.setBegin(SS.getRange().getBegin());
911 Diag(CCLoc, diag::err_non_type_template_in_nested_name_specifier)
912 << (TD && isa<VarTemplateDecl>(TD)) << Template.get() << R;
913 NoteAllFoundTemplates(Template.get());
917 // We were able to resolve the template name to an actual template.
918 // Build an appropriate nested-name-specifier.
919 QualType T = CheckTemplateIdType(Template.get(), TemplateNameLoc,
924 // Alias template specializations can produce types which are not valid
925 // nested name specifiers.
926 if (!T->isDependentType() && !T->getAs<TagType>()) {
927 Diag(TemplateNameLoc, diag::err_nested_name_spec_non_tag) << T;
928 NoteAllFoundTemplates(Template.get());
932 // Provide source-location information for the template specialization type.
933 TypeLocBuilder Builder;
934 TemplateSpecializationTypeLoc SpecTL
935 = Builder.push<TemplateSpecializationTypeLoc>(T);
936 SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
937 SpecTL.setTemplateNameLoc(TemplateNameLoc);
938 SpecTL.setLAngleLoc(LAngleLoc);
939 SpecTL.setRAngleLoc(RAngleLoc);
940 for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I)
941 SpecTL.setArgLocInfo(I, TemplateArgs[I].getLocInfo());
944 SS.Extend(Context, TemplateKWLoc, Builder.getTypeLocInContext(Context, T),
950 /// \brief A structure that stores a nested-name-specifier annotation,
951 /// including both the nested-name-specifier
952 struct NestedNameSpecifierAnnotation {
953 NestedNameSpecifier *NNS;
957 void *Sema::SaveNestedNameSpecifierAnnotation(CXXScopeSpec &SS) {
958 if (SS.isEmpty() || SS.isInvalid())
961 void *Mem = Context.Allocate((sizeof(NestedNameSpecifierAnnotation) +
963 llvm::alignOf<NestedNameSpecifierAnnotation>());
964 NestedNameSpecifierAnnotation *Annotation
965 = new (Mem) NestedNameSpecifierAnnotation;
966 Annotation->NNS = SS.getScopeRep();
967 memcpy(Annotation + 1, SS.location_data(), SS.location_size());
971 void Sema::RestoreNestedNameSpecifierAnnotation(void *AnnotationPtr,
972 SourceRange AnnotationRange,
974 if (!AnnotationPtr) {
975 SS.SetInvalid(AnnotationRange);
979 NestedNameSpecifierAnnotation *Annotation
980 = static_cast<NestedNameSpecifierAnnotation *>(AnnotationPtr);
981 SS.Adopt(NestedNameSpecifierLoc(Annotation->NNS, Annotation + 1));
984 bool Sema::ShouldEnterDeclaratorScope(Scope *S, const CXXScopeSpec &SS) {
985 assert(SS.isSet() && "Parser passed invalid CXXScopeSpec.");
987 NestedNameSpecifier *Qualifier = SS.getScopeRep();
989 // There are only two places a well-formed program may qualify a
990 // declarator: first, when defining a namespace or class member
991 // out-of-line, and second, when naming an explicitly-qualified
992 // friend function. The latter case is governed by
993 // C++03 [basic.lookup.unqual]p10:
994 // In a friend declaration naming a member function, a name used
995 // in the function declarator and not part of a template-argument
996 // in a template-id is first looked up in the scope of the member
997 // function's class. If it is not found, or if the name is part of
998 // a template-argument in a template-id, the look up is as
999 // described for unqualified names in the definition of the class
1000 // granting friendship.
1001 // i.e. we don't push a scope unless it's a class member.
1003 switch (Qualifier->getKind()) {
1004 case NestedNameSpecifier::Global:
1005 case NestedNameSpecifier::Namespace:
1006 case NestedNameSpecifier::NamespaceAlias:
1007 // These are always namespace scopes. We never want to enter a
1008 // namespace scope from anything but a file context.
1009 return CurContext->getRedeclContext()->isFileContext();
1011 case NestedNameSpecifier::Identifier:
1012 case NestedNameSpecifier::TypeSpec:
1013 case NestedNameSpecifier::TypeSpecWithTemplate:
1014 case NestedNameSpecifier::Super:
1015 // These are never namespace scopes.
1019 llvm_unreachable("Invalid NestedNameSpecifier::Kind!");
1022 /// ActOnCXXEnterDeclaratorScope - Called when a C++ scope specifier (global
1023 /// scope or nested-name-specifier) is parsed, part of a declarator-id.
1024 /// After this method is called, according to [C++ 3.4.3p3], names should be
1025 /// looked up in the declarator-id's scope, until the declarator is parsed and
1026 /// ActOnCXXExitDeclaratorScope is called.
1027 /// The 'SS' should be a non-empty valid CXXScopeSpec.
1028 bool Sema::ActOnCXXEnterDeclaratorScope(Scope *S, CXXScopeSpec &SS) {
1029 assert(SS.isSet() && "Parser passed invalid CXXScopeSpec.");
1031 if (SS.isInvalid()) return true;
1033 DeclContext *DC = computeDeclContext(SS, true);
1034 if (!DC) return true;
1036 // Before we enter a declarator's context, we need to make sure that
1037 // it is a complete declaration context.
1038 if (!DC->isDependentContext() && RequireCompleteDeclContext(SS, DC))
1041 EnterDeclaratorContext(S, DC);
1043 // Rebuild the nested name specifier for the new scope.
1044 if (DC->isDependentContext())
1045 RebuildNestedNameSpecifierInCurrentInstantiation(SS);
1050 /// ActOnCXXExitDeclaratorScope - Called when a declarator that previously
1051 /// invoked ActOnCXXEnterDeclaratorScope(), is finished. 'SS' is the same
1052 /// CXXScopeSpec that was passed to ActOnCXXEnterDeclaratorScope as well.
1053 /// Used to indicate that names should revert to being looked up in the
1055 void Sema::ActOnCXXExitDeclaratorScope(Scope *S, const CXXScopeSpec &SS) {
1056 assert(SS.isSet() && "Parser passed invalid CXXScopeSpec.");
1059 assert(!SS.isInvalid() && computeDeclContext(SS, true) &&
1060 "exiting declarator scope we never really entered");
1061 ExitDeclaratorContext(S);