1 //===--- SemaCXXScopeSpec.cpp - Semantic Analysis for C++ scope specifiers-===//
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
7 //===----------------------------------------------------------------------===//
9 // This file implements C++ semantic analysis for scope specifiers.
11 //===----------------------------------------------------------------------===//
13 #include "TypeLocBuilder.h"
14 #include "clang/AST/ASTContext.h"
15 #include "clang/AST/DeclTemplate.h"
16 #include "clang/AST/ExprCXX.h"
17 #include "clang/AST/NestedNameSpecifier.h"
18 #include "clang/Basic/PartialDiagnostic.h"
19 #include "clang/Sema/DeclSpec.h"
20 #include "clang/Sema/Lookup.h"
21 #include "clang/Sema/SemaInternal.h"
22 #include "clang/Sema/Template.h"
23 #include "llvm/ADT/STLExtras.h"
24 using namespace clang;
26 /// Find the current instantiation that associated with the given type.
27 static CXXRecordDecl *getCurrentInstantiationOf(QualType T,
28 DeclContext *CurContext) {
32 const Type *Ty = T->getCanonicalTypeInternal().getTypePtr();
33 if (const RecordType *RecordTy = dyn_cast<RecordType>(Ty)) {
34 CXXRecordDecl *Record = cast<CXXRecordDecl>(RecordTy->getDecl());
35 if (!Record->isDependentContext() ||
36 Record->isCurrentInstantiation(CurContext))
40 } else if (isa<InjectedClassNameType>(Ty))
41 return cast<InjectedClassNameType>(Ty)->getDecl();
46 /// Compute the DeclContext that is associated with the given type.
48 /// \param T the type for which we are attempting to find a DeclContext.
50 /// \returns the declaration context represented by the type T,
51 /// or NULL if the declaration context cannot be computed (e.g., because it is
52 /// dependent and not the current instantiation).
53 DeclContext *Sema::computeDeclContext(QualType T) {
54 if (!T->isDependentType())
55 if (const TagType *Tag = T->getAs<TagType>())
56 return Tag->getDecl();
58 return ::getCurrentInstantiationOf(T, CurContext);
61 /// Compute the DeclContext that is associated with the given
64 /// \param SS the C++ scope specifier as it appears in the source
66 /// \param EnteringContext when true, we will be entering the context of
67 /// this scope specifier, so we can retrieve the declaration context of a
68 /// class template or class template partial specialization even if it is
69 /// not the current instantiation.
71 /// \returns the declaration context represented by the scope specifier @p SS,
72 /// or NULL if the declaration context cannot be computed (e.g., because it is
73 /// dependent and not the current instantiation).
74 DeclContext *Sema::computeDeclContext(const CXXScopeSpec &SS,
75 bool EnteringContext) {
76 if (!SS.isSet() || SS.isInvalid())
79 NestedNameSpecifier *NNS = SS.getScopeRep();
80 if (NNS->isDependent()) {
81 // If this nested-name-specifier refers to the current
82 // instantiation, return its DeclContext.
83 if (CXXRecordDecl *Record = getCurrentInstantiationOf(NNS))
86 if (EnteringContext) {
87 const Type *NNSType = NNS->getAsType();
92 // Look through type alias templates, per C++0x [temp.dep.type]p1.
93 NNSType = Context.getCanonicalType(NNSType);
94 if (const TemplateSpecializationType *SpecType
95 = NNSType->getAs<TemplateSpecializationType>()) {
96 // We are entering the context of the nested name specifier, so try to
97 // match the nested name specifier to either a primary class template
98 // or a class template partial specialization.
99 if (ClassTemplateDecl *ClassTemplate
100 = dyn_cast_or_null<ClassTemplateDecl>(
101 SpecType->getTemplateName().getAsTemplateDecl())) {
103 = Context.getCanonicalType(QualType(SpecType, 0));
105 // If the type of the nested name specifier is the same as the
106 // injected class name of the named class template, we're entering
107 // into that class template definition.
109 = ClassTemplate->getInjectedClassNameSpecialization();
110 if (Context.hasSameType(Injected, ContextType))
111 return ClassTemplate->getTemplatedDecl();
113 // If the type of the nested name specifier is the same as the
114 // type of one of the class template's class template partial
115 // specializations, we're entering into the definition of that
116 // class template partial specialization.
117 if (ClassTemplatePartialSpecializationDecl *PartialSpec
118 = ClassTemplate->findPartialSpecialization(ContextType)) {
119 // A declaration of the partial specialization must be visible.
120 // We can always recover here, because this only happens when we're
121 // entering the context, and that can't happen in a SFINAE context.
122 assert(!isSFINAEContext() &&
123 "partial specialization scope specifier in SFINAE context?");
124 if (!hasVisibleDeclaration(PartialSpec))
125 diagnoseMissingImport(SS.getLastQualifierNameLoc(), PartialSpec,
126 MissingImportKind::PartialSpecialization,
131 } else if (const RecordType *RecordT = NNSType->getAs<RecordType>()) {
132 // The nested name specifier refers to a member of a class template.
133 return RecordT->getDecl();
140 switch (NNS->getKind()) {
141 case NestedNameSpecifier::Identifier:
142 llvm_unreachable("Dependent nested-name-specifier has no DeclContext");
144 case NestedNameSpecifier::Namespace:
145 return NNS->getAsNamespace();
147 case NestedNameSpecifier::NamespaceAlias:
148 return NNS->getAsNamespaceAlias()->getNamespace();
150 case NestedNameSpecifier::TypeSpec:
151 case NestedNameSpecifier::TypeSpecWithTemplate: {
152 const TagType *Tag = NNS->getAsType()->getAs<TagType>();
153 assert(Tag && "Non-tag type in nested-name-specifier");
154 return Tag->getDecl();
157 case NestedNameSpecifier::Global:
158 return Context.getTranslationUnitDecl();
160 case NestedNameSpecifier::Super:
161 return NNS->getAsRecordDecl();
164 llvm_unreachable("Invalid NestedNameSpecifier::Kind!");
167 bool Sema::isDependentScopeSpecifier(const CXXScopeSpec &SS) {
168 if (!SS.isSet() || SS.isInvalid())
171 return SS.getScopeRep()->isDependent();
174 /// If the given nested name specifier refers to the current
175 /// instantiation, return the declaration that corresponds to that
176 /// current instantiation (C++0x [temp.dep.type]p1).
178 /// \param NNS a dependent nested name specifier.
179 CXXRecordDecl *Sema::getCurrentInstantiationOf(NestedNameSpecifier *NNS) {
180 assert(getLangOpts().CPlusPlus && "Only callable in C++");
181 assert(NNS->isDependent() && "Only dependent nested-name-specifier allowed");
183 if (!NNS->getAsType())
186 QualType T = QualType(NNS->getAsType(), 0);
187 return ::getCurrentInstantiationOf(T, CurContext);
190 /// Require that the context specified by SS be complete.
192 /// If SS refers to a type, this routine checks whether the type is
193 /// complete enough (or can be made complete enough) for name lookup
194 /// into the DeclContext. A type that is not yet completed can be
195 /// considered "complete enough" if it is a class/struct/union/enum
196 /// that is currently being defined. Or, if we have a type that names
197 /// a class template specialization that is not a complete type, we
198 /// will attempt to instantiate that class template.
199 bool Sema::RequireCompleteDeclContext(CXXScopeSpec &SS,
201 assert(DC && "given null context");
203 TagDecl *tag = dyn_cast<TagDecl>(DC);
205 // If this is a dependent type, then we consider it complete.
206 // FIXME: This is wrong; we should require a (visible) definition to
207 // exist in this case too.
208 if (!tag || tag->isDependentContext())
211 // Grab the tag definition, if there is one.
212 QualType type = Context.getTypeDeclType(tag);
213 tag = type->getAsTagDecl();
215 // If we're currently defining this type, then lookup into the
216 // type is okay: don't complain that it isn't complete yet.
217 if (tag->isBeingDefined())
220 SourceLocation loc = SS.getLastQualifierNameLoc();
221 if (loc.isInvalid()) loc = SS.getRange().getBegin();
223 // The type must be complete.
224 if (RequireCompleteType(loc, type, diag::err_incomplete_nested_name_spec,
226 SS.SetInvalid(SS.getRange());
230 // Fixed enum types are complete, but they aren't valid as scopes
231 // until we see a definition, so awkwardly pull out this special
233 auto *EnumD = dyn_cast<EnumDecl>(tag);
236 if (EnumD->isCompleteDefinition()) {
237 // If we know about the definition but it is not visible, complain.
238 NamedDecl *SuggestedDef = nullptr;
239 if (!hasVisibleDefinition(EnumD, &SuggestedDef,
240 /*OnlyNeedComplete*/false)) {
241 // If the user is going to see an error here, recover by making the
242 // definition visible.
243 bool TreatAsComplete = !isSFINAEContext();
244 diagnoseMissingImport(loc, SuggestedDef, MissingImportKind::Definition,
245 /*Recover*/TreatAsComplete);
246 return !TreatAsComplete;
251 // Try to instantiate the definition, if this is a specialization of an
252 // enumeration temploid.
253 if (EnumDecl *Pattern = EnumD->getInstantiatedFromMemberEnum()) {
254 MemberSpecializationInfo *MSI = EnumD->getMemberSpecializationInfo();
255 if (MSI->getTemplateSpecializationKind() != TSK_ExplicitSpecialization) {
256 if (InstantiateEnum(loc, EnumD, Pattern,
257 getTemplateInstantiationArgs(EnumD),
258 TSK_ImplicitInstantiation)) {
259 SS.SetInvalid(SS.getRange());
266 Diag(loc, diag::err_incomplete_nested_name_spec)
267 << type << SS.getRange();
268 SS.SetInvalid(SS.getRange());
272 bool Sema::ActOnCXXGlobalScopeSpecifier(SourceLocation CCLoc,
274 SS.MakeGlobal(Context, CCLoc);
278 bool Sema::ActOnSuperScopeSpecifier(SourceLocation SuperLoc,
279 SourceLocation ColonColonLoc,
281 CXXRecordDecl *RD = nullptr;
282 for (Scope *S = getCurScope(); S; S = S->getParent()) {
283 if (S->isFunctionScope()) {
284 if (CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(S->getEntity()))
285 RD = MD->getParent();
288 if (S->isClassScope()) {
289 RD = cast<CXXRecordDecl>(S->getEntity());
295 Diag(SuperLoc, diag::err_invalid_super_scope);
297 } else if (RD->isLambda()) {
298 Diag(SuperLoc, diag::err_super_in_lambda_unsupported);
300 } else if (RD->getNumBases() == 0) {
301 Diag(SuperLoc, diag::err_no_base_classes) << RD->getName();
305 SS.MakeSuper(Context, RD, SuperLoc, ColonColonLoc);
309 /// Determines whether the given declaration is an valid acceptable
310 /// result for name lookup of a nested-name-specifier.
311 /// \param SD Declaration checked for nested-name-specifier.
312 /// \param IsExtension If not null and the declaration is accepted as an
313 /// extension, the pointed variable is assigned true.
314 bool Sema::isAcceptableNestedNameSpecifier(const NamedDecl *SD,
319 SD = SD->getUnderlyingDecl();
321 // Namespace and namespace aliases are fine.
322 if (isa<NamespaceDecl>(SD))
325 if (!isa<TypeDecl>(SD))
328 // Determine whether we have a class (or, in C++11, an enum) or
329 // a typedef thereof. If so, build the nested-name-specifier.
330 QualType T = Context.getTypeDeclType(cast<TypeDecl>(SD));
331 if (T->isDependentType())
333 if (const TypedefNameDecl *TD = dyn_cast<TypedefNameDecl>(SD)) {
334 if (TD->getUnderlyingType()->isRecordType())
336 if (TD->getUnderlyingType()->isEnumeralType()) {
337 if (Context.getLangOpts().CPlusPlus11)
342 } else if (isa<RecordDecl>(SD)) {
344 } else if (isa<EnumDecl>(SD)) {
345 if (Context.getLangOpts().CPlusPlus11)
354 /// If the given nested-name-specifier begins with a bare identifier
355 /// (e.g., Base::), perform name lookup for that identifier as a
356 /// nested-name-specifier within the given scope, and return the result of that
358 NamedDecl *Sema::FindFirstQualifierInScope(Scope *S, NestedNameSpecifier *NNS) {
362 while (NNS->getPrefix())
363 NNS = NNS->getPrefix();
365 if (NNS->getKind() != NestedNameSpecifier::Identifier)
368 LookupResult Found(*this, NNS->getAsIdentifier(), SourceLocation(),
369 LookupNestedNameSpecifierName);
370 LookupName(Found, S);
371 assert(!Found.isAmbiguous() && "Cannot handle ambiguities here yet");
373 if (!Found.isSingleResult())
376 NamedDecl *Result = Found.getFoundDecl();
377 if (isAcceptableNestedNameSpecifier(Result))
383 bool Sema::isNonTypeNestedNameSpecifier(Scope *S, CXXScopeSpec &SS,
384 NestedNameSpecInfo &IdInfo) {
385 QualType ObjectType = GetTypeFromParser(IdInfo.ObjectType);
386 LookupResult Found(*this, IdInfo.Identifier, IdInfo.IdentifierLoc,
387 LookupNestedNameSpecifierName);
389 // Determine where to perform name lookup
390 DeclContext *LookupCtx = nullptr;
391 bool isDependent = false;
392 if (!ObjectType.isNull()) {
393 // This nested-name-specifier occurs in a member access expression, e.g.,
394 // x->B::f, and we are looking into the type of the object.
395 assert(!SS.isSet() && "ObjectType and scope specifier cannot coexist");
396 LookupCtx = computeDeclContext(ObjectType);
397 isDependent = ObjectType->isDependentType();
398 } else if (SS.isSet()) {
399 // This nested-name-specifier occurs after another nested-name-specifier,
400 // so long into the context associated with the prior nested-name-specifier.
401 LookupCtx = computeDeclContext(SS, false);
402 isDependent = isDependentScopeSpecifier(SS);
403 Found.setContextRange(SS.getRange());
407 // Perform "qualified" name lookup into the declaration context we
408 // computed, which is either the type of the base of a member access
409 // expression or the declaration context associated with a prior
410 // nested-name-specifier.
412 // The declaration context must be complete.
413 if (!LookupCtx->isDependentContext() &&
414 RequireCompleteDeclContext(SS, LookupCtx))
417 LookupQualifiedName(Found, LookupCtx);
418 } else if (isDependent) {
421 LookupName(Found, S);
423 Found.suppressDiagnostics();
425 return Found.getAsSingle<NamespaceDecl>();
430 // Callback to only accept typo corrections that can be a valid C++ member
431 // intializer: either a non-static field member or a base class.
432 class NestedNameSpecifierValidatorCCC final
433 : public CorrectionCandidateCallback {
435 explicit NestedNameSpecifierValidatorCCC(Sema &SRef)
438 bool ValidateCandidate(const TypoCorrection &candidate) override {
439 return SRef.isAcceptableNestedNameSpecifier(candidate.getCorrectionDecl());
442 std::unique_ptr<CorrectionCandidateCallback> clone() override {
443 return llvm::make_unique<NestedNameSpecifierValidatorCCC>(*this);
452 /// Build a new nested-name-specifier for "identifier::", as described
453 /// by ActOnCXXNestedNameSpecifier.
455 /// \param S Scope in which the nested-name-specifier occurs.
456 /// \param IdInfo Parser information about an identifier in the
457 /// nested-name-spec.
458 /// \param EnteringContext If true, enter the context specified by the
459 /// nested-name-specifier.
460 /// \param SS Optional nested name specifier preceding the identifier.
461 /// \param ScopeLookupResult Provides the result of name lookup within the
462 /// scope of the nested-name-specifier that was computed at template
464 /// \param ErrorRecoveryLookup Specifies if the method is called to improve
465 /// error recovery and what kind of recovery is performed.
466 /// \param IsCorrectedToColon If not null, suggestion of replace '::' -> ':'
467 /// are allowed. The bool value pointed by this parameter is set to
468 /// 'true' if the identifier is treated as if it was followed by ':',
470 /// \param OnlyNamespace If true, only considers namespaces in lookup.
472 /// This routine differs only slightly from ActOnCXXNestedNameSpecifier, in
473 /// that it contains an extra parameter \p ScopeLookupResult, which provides
474 /// the result of name lookup within the scope of the nested-name-specifier
475 /// that was computed at template definition time.
477 /// If ErrorRecoveryLookup is true, then this call is used to improve error
478 /// recovery. This means that it should not emit diagnostics, it should
479 /// just return true on failure. It also means it should only return a valid
480 /// scope if it *knows* that the result is correct. It should not return in a
481 /// dependent context, for example. Nor will it extend \p SS with the scope
483 bool Sema::BuildCXXNestedNameSpecifier(Scope *S, NestedNameSpecInfo &IdInfo,
484 bool EnteringContext, CXXScopeSpec &SS,
485 NamedDecl *ScopeLookupResult,
486 bool ErrorRecoveryLookup,
487 bool *IsCorrectedToColon,
488 bool OnlyNamespace) {
489 if (IdInfo.Identifier->isEditorPlaceholder())
491 LookupResult Found(*this, IdInfo.Identifier, IdInfo.IdentifierLoc,
492 OnlyNamespace ? LookupNamespaceName
493 : LookupNestedNameSpecifierName);
494 QualType ObjectType = GetTypeFromParser(IdInfo.ObjectType);
496 // Determine where to perform name lookup
497 DeclContext *LookupCtx = nullptr;
498 bool isDependent = false;
499 if (IsCorrectedToColon)
500 *IsCorrectedToColon = false;
501 if (!ObjectType.isNull()) {
502 // This nested-name-specifier occurs in a member access expression, e.g.,
503 // x->B::f, and we are looking into the type of the object.
504 assert(!SS.isSet() && "ObjectType and scope specifier cannot coexist");
505 LookupCtx = computeDeclContext(ObjectType);
506 isDependent = ObjectType->isDependentType();
507 } else if (SS.isSet()) {
508 // This nested-name-specifier occurs after another nested-name-specifier,
509 // so look into the context associated with the prior nested-name-specifier.
510 LookupCtx = computeDeclContext(SS, EnteringContext);
511 isDependent = isDependentScopeSpecifier(SS);
512 Found.setContextRange(SS.getRange());
515 bool ObjectTypeSearchedInScope = false;
517 // Perform "qualified" name lookup into the declaration context we
518 // computed, which is either the type of the base of a member access
519 // expression or the declaration context associated with a prior
520 // nested-name-specifier.
522 // The declaration context must be complete.
523 if (!LookupCtx->isDependentContext() &&
524 RequireCompleteDeclContext(SS, LookupCtx))
527 LookupQualifiedName(Found, LookupCtx);
529 if (!ObjectType.isNull() && Found.empty()) {
530 // C++ [basic.lookup.classref]p4:
531 // If the id-expression in a class member access is a qualified-id of
534 // class-name-or-namespace-name::...
536 // the class-name-or-namespace-name following the . or -> operator is
537 // looked up both in the context of the entire postfix-expression and in
538 // the scope of the class of the object expression. If the name is found
539 // only in the scope of the class of the object expression, the name
540 // shall refer to a class-name. If the name is found only in the
541 // context of the entire postfix-expression, the name shall refer to a
542 // class-name or namespace-name. [...]
544 // Qualified name lookup into a class will not find a namespace-name,
545 // so we do not need to diagnose that case specifically. However,
546 // this qualified name lookup may find nothing. In that case, perform
547 // unqualified name lookup in the given scope (if available) or
548 // reconstruct the result from when name lookup was performed at template
551 LookupName(Found, S);
552 else if (ScopeLookupResult)
553 Found.addDecl(ScopeLookupResult);
555 ObjectTypeSearchedInScope = true;
557 } else if (!isDependent) {
558 // Perform unqualified name lookup in the current scope.
559 LookupName(Found, S);
562 if (Found.isAmbiguous())
565 // If we performed lookup into a dependent context and did not find anything,
566 // that's fine: just build a dependent nested-name-specifier.
567 if (Found.empty() && isDependent &&
568 !(LookupCtx && LookupCtx->isRecord() &&
569 (!cast<CXXRecordDecl>(LookupCtx)->hasDefinition() ||
570 !cast<CXXRecordDecl>(LookupCtx)->hasAnyDependentBases()))) {
571 // Don't speculate if we're just trying to improve error recovery.
572 if (ErrorRecoveryLookup)
575 // We were not able to compute the declaration context for a dependent
576 // base object type or prior nested-name-specifier, so this
577 // nested-name-specifier refers to an unknown specialization. Just build
578 // a dependent nested-name-specifier.
579 SS.Extend(Context, IdInfo.Identifier, IdInfo.IdentifierLoc, IdInfo.CCLoc);
583 if (Found.empty() && !ErrorRecoveryLookup) {
584 // If identifier is not found as class-name-or-namespace-name, but is found
585 // as other entity, don't look for typos.
586 LookupResult R(*this, Found.getLookupNameInfo(), LookupOrdinaryName);
588 LookupQualifiedName(R, LookupCtx);
589 else if (S && !isDependent)
592 // Don't diagnose problems with this speculative lookup.
593 R.suppressDiagnostics();
594 // The identifier is found in ordinary lookup. If correction to colon is
595 // allowed, suggest replacement to ':'.
596 if (IsCorrectedToColon) {
597 *IsCorrectedToColon = true;
598 Diag(IdInfo.CCLoc, diag::err_nested_name_spec_is_not_class)
599 << IdInfo.Identifier << getLangOpts().CPlusPlus
600 << FixItHint::CreateReplacement(IdInfo.CCLoc, ":");
601 if (NamedDecl *ND = R.getAsSingle<NamedDecl>())
602 Diag(ND->getLocation(), diag::note_declared_at);
605 // Replacement '::' -> ':' is not allowed, just issue respective error.
606 Diag(R.getNameLoc(), OnlyNamespace
607 ? unsigned(diag::err_expected_namespace_name)
608 : unsigned(diag::err_expected_class_or_namespace))
609 << IdInfo.Identifier << getLangOpts().CPlusPlus;
610 if (NamedDecl *ND = R.getAsSingle<NamedDecl>())
611 Diag(ND->getLocation(), diag::note_entity_declared_at)
612 << IdInfo.Identifier;
617 if (Found.empty() && !ErrorRecoveryLookup && !getLangOpts().MSVCCompat) {
618 // We haven't found anything, and we're not recovering from a
619 // different kind of error, so look for typos.
620 DeclarationName Name = Found.getLookupName();
622 NestedNameSpecifierValidatorCCC CCC(*this);
623 if (TypoCorrection Corrected = CorrectTypo(
624 Found.getLookupNameInfo(), Found.getLookupKind(), S, &SS, CCC,
625 CTK_ErrorRecovery, LookupCtx, EnteringContext)) {
627 bool DroppedSpecifier =
628 Corrected.WillReplaceSpecifier() &&
629 Name.getAsString() == Corrected.getAsString(getLangOpts());
630 if (DroppedSpecifier)
632 diagnoseTypo(Corrected, PDiag(diag::err_no_member_suggest)
633 << Name << LookupCtx << DroppedSpecifier
636 diagnoseTypo(Corrected, PDiag(diag::err_undeclared_var_use_suggest)
639 if (Corrected.getCorrectionSpecifier())
640 SS.MakeTrivial(Context, Corrected.getCorrectionSpecifier(),
641 SourceRange(Found.getNameLoc()));
643 if (NamedDecl *ND = Corrected.getFoundDecl())
645 Found.setLookupName(Corrected.getCorrection());
647 Found.setLookupName(IdInfo.Identifier);
652 Found.isSingleResult() ? Found.getRepresentativeDecl() : nullptr;
653 bool IsExtension = false;
654 bool AcceptSpec = isAcceptableNestedNameSpecifier(SD, &IsExtension);
655 if (!AcceptSpec && IsExtension) {
657 Diag(IdInfo.IdentifierLoc, diag::ext_nested_name_spec_is_enum);
660 if (!ObjectType.isNull() && !ObjectTypeSearchedInScope &&
661 !getLangOpts().CPlusPlus11) {
662 // C++03 [basic.lookup.classref]p4:
663 // [...] If the name is found in both contexts, the
664 // class-name-or-namespace-name shall refer to the same entity.
666 // We already found the name in the scope of the object. Now, look
667 // into the current scope (the scope of the postfix-expression) to
668 // see if we can find the same name there. As above, if there is no
669 // scope, reconstruct the result from the template instantiation itself.
671 // Note that C++11 does *not* perform this redundant lookup.
672 NamedDecl *OuterDecl;
674 LookupResult FoundOuter(*this, IdInfo.Identifier, IdInfo.IdentifierLoc,
675 LookupNestedNameSpecifierName);
676 LookupName(FoundOuter, S);
677 OuterDecl = FoundOuter.getAsSingle<NamedDecl>();
679 OuterDecl = ScopeLookupResult;
681 if (isAcceptableNestedNameSpecifier(OuterDecl) &&
682 OuterDecl->getCanonicalDecl() != SD->getCanonicalDecl() &&
683 (!isa<TypeDecl>(OuterDecl) || !isa<TypeDecl>(SD) ||
684 !Context.hasSameType(
685 Context.getTypeDeclType(cast<TypeDecl>(OuterDecl)),
686 Context.getTypeDeclType(cast<TypeDecl>(SD))))) {
687 if (ErrorRecoveryLookup)
690 Diag(IdInfo.IdentifierLoc,
691 diag::err_nested_name_member_ref_lookup_ambiguous)
692 << IdInfo.Identifier;
693 Diag(SD->getLocation(), diag::note_ambig_member_ref_object_type)
695 Diag(OuterDecl->getLocation(), diag::note_ambig_member_ref_scope);
697 // Fall through so that we'll pick the name we found in the object
698 // type, since that's probably what the user wanted anyway.
702 if (auto *TD = dyn_cast_or_null<TypedefNameDecl>(SD))
703 MarkAnyDeclReferenced(TD->getLocation(), TD, /*OdrUse=*/false);
705 // If we're just performing this lookup for error-recovery purposes,
706 // don't extend the nested-name-specifier. Just return now.
707 if (ErrorRecoveryLookup)
710 // The use of a nested name specifier may trigger deprecation warnings.
711 DiagnoseUseOfDecl(SD, IdInfo.CCLoc);
713 if (NamespaceDecl *Namespace = dyn_cast<NamespaceDecl>(SD)) {
714 SS.Extend(Context, Namespace, IdInfo.IdentifierLoc, IdInfo.CCLoc);
718 if (NamespaceAliasDecl *Alias = dyn_cast<NamespaceAliasDecl>(SD)) {
719 SS.Extend(Context, Alias, IdInfo.IdentifierLoc, IdInfo.CCLoc);
724 Context.getTypeDeclType(cast<TypeDecl>(SD->getUnderlyingDecl()));
726 if (isa<InjectedClassNameType>(T)) {
727 InjectedClassNameTypeLoc InjectedTL
728 = TLB.push<InjectedClassNameTypeLoc>(T);
729 InjectedTL.setNameLoc(IdInfo.IdentifierLoc);
730 } else if (isa<RecordType>(T)) {
731 RecordTypeLoc RecordTL = TLB.push<RecordTypeLoc>(T);
732 RecordTL.setNameLoc(IdInfo.IdentifierLoc);
733 } else if (isa<TypedefType>(T)) {
734 TypedefTypeLoc TypedefTL = TLB.push<TypedefTypeLoc>(T);
735 TypedefTL.setNameLoc(IdInfo.IdentifierLoc);
736 } else if (isa<EnumType>(T)) {
737 EnumTypeLoc EnumTL = TLB.push<EnumTypeLoc>(T);
738 EnumTL.setNameLoc(IdInfo.IdentifierLoc);
739 } else if (isa<TemplateTypeParmType>(T)) {
740 TemplateTypeParmTypeLoc TemplateTypeTL
741 = TLB.push<TemplateTypeParmTypeLoc>(T);
742 TemplateTypeTL.setNameLoc(IdInfo.IdentifierLoc);
743 } else if (isa<UnresolvedUsingType>(T)) {
744 UnresolvedUsingTypeLoc UnresolvedTL
745 = TLB.push<UnresolvedUsingTypeLoc>(T);
746 UnresolvedTL.setNameLoc(IdInfo.IdentifierLoc);
747 } else if (isa<SubstTemplateTypeParmType>(T)) {
748 SubstTemplateTypeParmTypeLoc TL
749 = TLB.push<SubstTemplateTypeParmTypeLoc>(T);
750 TL.setNameLoc(IdInfo.IdentifierLoc);
751 } else if (isa<SubstTemplateTypeParmPackType>(T)) {
752 SubstTemplateTypeParmPackTypeLoc TL
753 = TLB.push<SubstTemplateTypeParmPackTypeLoc>(T);
754 TL.setNameLoc(IdInfo.IdentifierLoc);
756 llvm_unreachable("Unhandled TypeDecl node in nested-name-specifier");
759 if (T->isEnumeralType())
760 Diag(IdInfo.IdentifierLoc, diag::warn_cxx98_compat_enum_nested_name_spec);
762 SS.Extend(Context, SourceLocation(), TLB.getTypeLocInContext(Context, T),
767 // Otherwise, we have an error case. If we don't want diagnostics, just
768 // return an error now.
769 if (ErrorRecoveryLookup)
772 // If we didn't find anything during our lookup, try again with
773 // ordinary name lookup, which can help us produce better error
776 Found.clear(LookupOrdinaryName);
777 LookupName(Found, S);
780 // In Microsoft mode, if we are within a templated function and we can't
781 // resolve Identifier, then extend the SS with Identifier. This will have
782 // the effect of resolving Identifier during template instantiation.
783 // The goal is to be able to resolve a function call whose
784 // nested-name-specifier is located inside a dependent base class.
789 // static void foo2() { }
791 // template <class T> class A { public: typedef C D; };
793 // template <class T> class B : public A<T> {
795 // void foo() { D::foo2(); }
797 if (getLangOpts().MSVCCompat) {
798 DeclContext *DC = LookupCtx ? LookupCtx : CurContext;
799 if (DC->isDependentContext() && DC->isFunctionOrMethod()) {
800 CXXRecordDecl *ContainingClass = dyn_cast<CXXRecordDecl>(DC->getParent());
801 if (ContainingClass && ContainingClass->hasAnyDependentBases()) {
802 Diag(IdInfo.IdentifierLoc,
803 diag::ext_undeclared_unqual_id_with_dependent_base)
804 << IdInfo.Identifier << ContainingClass;
805 SS.Extend(Context, IdInfo.Identifier, IdInfo.IdentifierLoc,
812 if (!Found.empty()) {
813 if (TypeDecl *TD = Found.getAsSingle<TypeDecl>())
814 Diag(IdInfo.IdentifierLoc, diag::err_expected_class_or_namespace)
815 << Context.getTypeDeclType(TD) << getLangOpts().CPlusPlus;
817 Diag(IdInfo.IdentifierLoc, diag::err_expected_class_or_namespace)
818 << IdInfo.Identifier << getLangOpts().CPlusPlus;
819 if (NamedDecl *ND = Found.getAsSingle<NamedDecl>())
820 Diag(ND->getLocation(), diag::note_entity_declared_at)
821 << IdInfo.Identifier;
823 } else if (SS.isSet())
824 Diag(IdInfo.IdentifierLoc, diag::err_no_member) << IdInfo.Identifier
825 << LookupCtx << SS.getRange();
827 Diag(IdInfo.IdentifierLoc, diag::err_undeclared_var_use)
828 << IdInfo.Identifier;
833 bool Sema::ActOnCXXNestedNameSpecifier(Scope *S, NestedNameSpecInfo &IdInfo,
834 bool EnteringContext, CXXScopeSpec &SS,
835 bool ErrorRecoveryLookup,
836 bool *IsCorrectedToColon,
837 bool OnlyNamespace) {
841 return BuildCXXNestedNameSpecifier(S, IdInfo, EnteringContext, SS,
842 /*ScopeLookupResult=*/nullptr, false,
843 IsCorrectedToColon, OnlyNamespace);
846 bool Sema::ActOnCXXNestedNameSpecifierDecltype(CXXScopeSpec &SS,
848 SourceLocation ColonColonLoc) {
849 if (SS.isInvalid() || DS.getTypeSpecType() == DeclSpec::TST_error)
852 assert(DS.getTypeSpecType() == DeclSpec::TST_decltype);
854 QualType T = BuildDecltypeType(DS.getRepAsExpr(), DS.getTypeSpecTypeLoc());
858 if (!T->isDependentType() && !T->getAs<TagType>()) {
859 Diag(DS.getTypeSpecTypeLoc(), diag::err_expected_class_or_namespace)
860 << T << getLangOpts().CPlusPlus;
865 DecltypeTypeLoc DecltypeTL = TLB.push<DecltypeTypeLoc>(T);
866 DecltypeTL.setNameLoc(DS.getTypeSpecTypeLoc());
867 SS.Extend(Context, SourceLocation(), TLB.getTypeLocInContext(Context, T),
872 /// IsInvalidUnlessNestedName - This method is used for error recovery
873 /// purposes to determine whether the specified identifier is only valid as
874 /// a nested name specifier, for example a namespace name. It is
875 /// conservatively correct to always return false from this method.
877 /// The arguments are the same as those passed to ActOnCXXNestedNameSpecifier.
878 bool Sema::IsInvalidUnlessNestedName(Scope *S, CXXScopeSpec &SS,
879 NestedNameSpecInfo &IdInfo,
880 bool EnteringContext) {
884 return !BuildCXXNestedNameSpecifier(S, IdInfo, EnteringContext, SS,
885 /*ScopeLookupResult=*/nullptr, true);
888 bool Sema::ActOnCXXNestedNameSpecifier(Scope *S,
890 SourceLocation TemplateKWLoc,
891 TemplateTy OpaqueTemplate,
892 SourceLocation TemplateNameLoc,
893 SourceLocation LAngleLoc,
894 ASTTemplateArgsPtr TemplateArgsIn,
895 SourceLocation RAngleLoc,
896 SourceLocation CCLoc,
897 bool EnteringContext) {
901 TemplateName Template = OpaqueTemplate.get();
903 // Translate the parser's template argument list in our AST format.
904 TemplateArgumentListInfo TemplateArgs(LAngleLoc, RAngleLoc);
905 translateTemplateArguments(TemplateArgsIn, TemplateArgs);
907 DependentTemplateName *DTN = Template.getAsDependentTemplateName();
908 if (DTN && DTN->isIdentifier()) {
909 // Handle a dependent template specialization for which we cannot resolve
910 // the template name.
911 assert(DTN->getQualifier() == SS.getScopeRep());
912 QualType T = Context.getDependentTemplateSpecializationType(ETK_None,
914 DTN->getIdentifier(),
917 // Create source-location information for this type.
918 TypeLocBuilder Builder;
919 DependentTemplateSpecializationTypeLoc SpecTL
920 = Builder.push<DependentTemplateSpecializationTypeLoc>(T);
921 SpecTL.setElaboratedKeywordLoc(SourceLocation());
922 SpecTL.setQualifierLoc(SS.getWithLocInContext(Context));
923 SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
924 SpecTL.setTemplateNameLoc(TemplateNameLoc);
925 SpecTL.setLAngleLoc(LAngleLoc);
926 SpecTL.setRAngleLoc(RAngleLoc);
927 for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I)
928 SpecTL.setArgLocInfo(I, TemplateArgs[I].getLocInfo());
930 SS.Extend(Context, TemplateKWLoc, Builder.getTypeLocInContext(Context, T),
935 // If we assumed an undeclared identifier was a template name, try to
936 // typo-correct it now.
937 if (Template.getAsAssumedTemplateName() &&
938 resolveAssumedTemplateNameAsType(S, Template, TemplateNameLoc))
941 TemplateDecl *TD = Template.getAsTemplateDecl();
942 if (Template.getAsOverloadedTemplate() || DTN ||
943 isa<FunctionTemplateDecl>(TD) || isa<VarTemplateDecl>(TD)) {
944 SourceRange R(TemplateNameLoc, RAngleLoc);
945 if (SS.getRange().isValid())
946 R.setBegin(SS.getRange().getBegin());
948 Diag(CCLoc, diag::err_non_type_template_in_nested_name_specifier)
949 << (TD && isa<VarTemplateDecl>(TD)) << Template << R;
950 NoteAllFoundTemplates(Template);
954 // We were able to resolve the template name to an actual template.
955 // Build an appropriate nested-name-specifier.
956 QualType T = CheckTemplateIdType(Template, TemplateNameLoc, TemplateArgs);
960 // Alias template specializations can produce types which are not valid
961 // nested name specifiers.
962 if (!T->isDependentType() && !T->getAs<TagType>()) {
963 Diag(TemplateNameLoc, diag::err_nested_name_spec_non_tag) << T;
964 NoteAllFoundTemplates(Template);
968 // Provide source-location information for the template specialization type.
969 TypeLocBuilder Builder;
970 TemplateSpecializationTypeLoc SpecTL
971 = Builder.push<TemplateSpecializationTypeLoc>(T);
972 SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
973 SpecTL.setTemplateNameLoc(TemplateNameLoc);
974 SpecTL.setLAngleLoc(LAngleLoc);
975 SpecTL.setRAngleLoc(RAngleLoc);
976 for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I)
977 SpecTL.setArgLocInfo(I, TemplateArgs[I].getLocInfo());
980 SS.Extend(Context, TemplateKWLoc, Builder.getTypeLocInContext(Context, T),
986 /// A structure that stores a nested-name-specifier annotation,
987 /// including both the nested-name-specifier
988 struct NestedNameSpecifierAnnotation {
989 NestedNameSpecifier *NNS;
993 void *Sema::SaveNestedNameSpecifierAnnotation(CXXScopeSpec &SS) {
994 if (SS.isEmpty() || SS.isInvalid())
997 void *Mem = Context.Allocate(
998 (sizeof(NestedNameSpecifierAnnotation) + SS.location_size()),
999 alignof(NestedNameSpecifierAnnotation));
1000 NestedNameSpecifierAnnotation *Annotation
1001 = new (Mem) NestedNameSpecifierAnnotation;
1002 Annotation->NNS = SS.getScopeRep();
1003 memcpy(Annotation + 1, SS.location_data(), SS.location_size());
1007 void Sema::RestoreNestedNameSpecifierAnnotation(void *AnnotationPtr,
1008 SourceRange AnnotationRange,
1010 if (!AnnotationPtr) {
1011 SS.SetInvalid(AnnotationRange);
1015 NestedNameSpecifierAnnotation *Annotation
1016 = static_cast<NestedNameSpecifierAnnotation *>(AnnotationPtr);
1017 SS.Adopt(NestedNameSpecifierLoc(Annotation->NNS, Annotation + 1));
1020 bool Sema::ShouldEnterDeclaratorScope(Scope *S, const CXXScopeSpec &SS) {
1021 assert(SS.isSet() && "Parser passed invalid CXXScopeSpec.");
1023 // Don't enter a declarator context when the current context is an Objective-C
1025 if (isa<ObjCContainerDecl>(CurContext) || isa<ObjCMethodDecl>(CurContext))
1028 NestedNameSpecifier *Qualifier = SS.getScopeRep();
1030 // There are only two places a well-formed program may qualify a
1031 // declarator: first, when defining a namespace or class member
1032 // out-of-line, and second, when naming an explicitly-qualified
1033 // friend function. The latter case is governed by
1034 // C++03 [basic.lookup.unqual]p10:
1035 // In a friend declaration naming a member function, a name used
1036 // in the function declarator and not part of a template-argument
1037 // in a template-id is first looked up in the scope of the member
1038 // function's class. If it is not found, or if the name is part of
1039 // a template-argument in a template-id, the look up is as
1040 // described for unqualified names in the definition of the class
1041 // granting friendship.
1042 // i.e. we don't push a scope unless it's a class member.
1044 switch (Qualifier->getKind()) {
1045 case NestedNameSpecifier::Global:
1046 case NestedNameSpecifier::Namespace:
1047 case NestedNameSpecifier::NamespaceAlias:
1048 // These are always namespace scopes. We never want to enter a
1049 // namespace scope from anything but a file context.
1050 return CurContext->getRedeclContext()->isFileContext();
1052 case NestedNameSpecifier::Identifier:
1053 case NestedNameSpecifier::TypeSpec:
1054 case NestedNameSpecifier::TypeSpecWithTemplate:
1055 case NestedNameSpecifier::Super:
1056 // These are never namespace scopes.
1060 llvm_unreachable("Invalid NestedNameSpecifier::Kind!");
1063 /// ActOnCXXEnterDeclaratorScope - Called when a C++ scope specifier (global
1064 /// scope or nested-name-specifier) is parsed, part of a declarator-id.
1065 /// After this method is called, according to [C++ 3.4.3p3], names should be
1066 /// looked up in the declarator-id's scope, until the declarator is parsed and
1067 /// ActOnCXXExitDeclaratorScope is called.
1068 /// The 'SS' should be a non-empty valid CXXScopeSpec.
1069 bool Sema::ActOnCXXEnterDeclaratorScope(Scope *S, CXXScopeSpec &SS) {
1070 assert(SS.isSet() && "Parser passed invalid CXXScopeSpec.");
1072 if (SS.isInvalid()) return true;
1074 DeclContext *DC = computeDeclContext(SS, true);
1075 if (!DC) return true;
1077 // Before we enter a declarator's context, we need to make sure that
1078 // it is a complete declaration context.
1079 if (!DC->isDependentContext() && RequireCompleteDeclContext(SS, DC))
1082 EnterDeclaratorContext(S, DC);
1084 // Rebuild the nested name specifier for the new scope.
1085 if (DC->isDependentContext())
1086 RebuildNestedNameSpecifierInCurrentInstantiation(SS);
1091 /// ActOnCXXExitDeclaratorScope - Called when a declarator that previously
1092 /// invoked ActOnCXXEnterDeclaratorScope(), is finished. 'SS' is the same
1093 /// CXXScopeSpec that was passed to ActOnCXXEnterDeclaratorScope as well.
1094 /// Used to indicate that names should revert to being looked up in the
1096 void Sema::ActOnCXXExitDeclaratorScope(Scope *S, const CXXScopeSpec &SS) {
1097 assert(SS.isSet() && "Parser passed invalid CXXScopeSpec.");
1100 assert(!SS.isInvalid() && computeDeclContext(SS, true) &&
1101 "exiting declarator scope we never really entered");
1102 ExitDeclaratorContext(S);