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//===--- SemaCXXScopeSpec.cpp - Semantic Analysis for C++ scope specifiers-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file implements C++ semantic analysis for scope specifiers.
//
//===----------------------------------------------------------------------===//
#include "TypeLocBuilder.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/DeclTemplate.h"
#include "clang/AST/ExprCXX.h"
#include "clang/AST/NestedNameSpecifier.h"
#include "clang/Basic/PartialDiagnostic.h"
#include "clang/Sema/DeclSpec.h"
#include "clang/Sema/Lookup.h"
#include "clang/Sema/SemaInternal.h"
#include "clang/Sema/Template.h"
#include "llvm/ADT/STLExtras.h"
using namespace clang;
/// Find the current instantiation that associated with the given type.
static CXXRecordDecl *getCurrentInstantiationOf(QualType T,
DeclContext *CurContext) {
if (T.isNull())
return nullptr;
const Type *Ty = T->getCanonicalTypeInternal().getTypePtr();
if (const RecordType *RecordTy = dyn_cast<RecordType>(Ty)) {
CXXRecordDecl *Record = cast<CXXRecordDecl>(RecordTy->getDecl());
if (!Record->isDependentContext() ||
Record->isCurrentInstantiation(CurContext))
return Record;
return nullptr;
} else if (isa<InjectedClassNameType>(Ty))
return cast<InjectedClassNameType>(Ty)->getDecl();
else
return nullptr;
}
/// Compute the DeclContext that is associated with the given type.
///
/// \param T the type for which we are attempting to find a DeclContext.
///
/// \returns the declaration context represented by the type T,
/// or NULL if the declaration context cannot be computed (e.g., because it is
/// dependent and not the current instantiation).
DeclContext *Sema::computeDeclContext(QualType T) {
if (!T->isDependentType())
if (const TagType *Tag = T->getAs<TagType>())
return Tag->getDecl();
return ::getCurrentInstantiationOf(T, CurContext);
}
/// Compute the DeclContext that is associated with the given
/// scope specifier.
///
/// \param SS the C++ scope specifier as it appears in the source
///
/// \param EnteringContext when true, we will be entering the context of
/// this scope specifier, so we can retrieve the declaration context of a
/// class template or class template partial specialization even if it is
/// not the current instantiation.
///
/// \returns the declaration context represented by the scope specifier @p SS,
/// or NULL if the declaration context cannot be computed (e.g., because it is
/// dependent and not the current instantiation).
DeclContext *Sema::computeDeclContext(const CXXScopeSpec &SS,
bool EnteringContext) {
if (!SS.isSet() || SS.isInvalid())
return nullptr;
NestedNameSpecifier *NNS = SS.getScopeRep();
if (NNS->isDependent()) {
// If this nested-name-specifier refers to the current
// instantiation, return its DeclContext.
if (CXXRecordDecl *Record = getCurrentInstantiationOf(NNS))
return Record;
if (EnteringContext) {
const Type *NNSType = NNS->getAsType();
if (!NNSType) {
return nullptr;
}
// Look through type alias templates, per C++0x [temp.dep.type]p1.
NNSType = Context.getCanonicalType(NNSType);
if (const TemplateSpecializationType *SpecType
= NNSType->getAs<TemplateSpecializationType>()) {
// We are entering the context of the nested name specifier, so try to
// match the nested name specifier to either a primary class template
// or a class template partial specialization.
if (ClassTemplateDecl *ClassTemplate
= dyn_cast_or_null<ClassTemplateDecl>(
SpecType->getTemplateName().getAsTemplateDecl())) {
QualType ContextType
= Context.getCanonicalType(QualType(SpecType, 0));
// If the type of the nested name specifier is the same as the
// injected class name of the named class template, we're entering
// into that class template definition.
QualType Injected
= ClassTemplate->getInjectedClassNameSpecialization();
if (Context.hasSameType(Injected, ContextType))
return ClassTemplate->getTemplatedDecl();
// If the type of the nested name specifier is the same as the
// type of one of the class template's class template partial
// specializations, we're entering into the definition of that
// class template partial specialization.
if (ClassTemplatePartialSpecializationDecl *PartialSpec
= ClassTemplate->findPartialSpecialization(ContextType)) {
// A declaration of the partial specialization must be visible.
// We can always recover here, because this only happens when we're
// entering the context, and that can't happen in a SFINAE context.
assert(!isSFINAEContext() &&
"partial specialization scope specifier in SFINAE context?");
if (!hasVisibleDeclaration(PartialSpec))
diagnoseMissingImport(SS.getLastQualifierNameLoc(), PartialSpec,
MissingImportKind::PartialSpecialization,
/*Recover*/true);
return PartialSpec;
}
}
} else if (const RecordType *RecordT = NNSType->getAs<RecordType>()) {
// The nested name specifier refers to a member of a class template.
return RecordT->getDecl();
}
}
return nullptr;
}
switch (NNS->getKind()) {
case NestedNameSpecifier::Identifier:
llvm_unreachable("Dependent nested-name-specifier has no DeclContext");
case NestedNameSpecifier::Namespace:
return NNS->getAsNamespace();
case NestedNameSpecifier::NamespaceAlias:
return NNS->getAsNamespaceAlias()->getNamespace();
case NestedNameSpecifier::TypeSpec:
case NestedNameSpecifier::TypeSpecWithTemplate: {
const TagType *Tag = NNS->getAsType()->getAs<TagType>();
assert(Tag && "Non-tag type in nested-name-specifier");
return Tag->getDecl();
}
case NestedNameSpecifier::Global:
return Context.getTranslationUnitDecl();
case NestedNameSpecifier::Super:
return NNS->getAsRecordDecl();
}
llvm_unreachable("Invalid NestedNameSpecifier::Kind!");
}
bool Sema::isDependentScopeSpecifier(const CXXScopeSpec &SS) {
if (!SS.isSet() || SS.isInvalid())
return false;
return SS.getScopeRep()->isDependent();
}
/// If the given nested name specifier refers to the current
/// instantiation, return the declaration that corresponds to that
/// current instantiation (C++0x [temp.dep.type]p1).
///
/// \param NNS a dependent nested name specifier.
CXXRecordDecl *Sema::getCurrentInstantiationOf(NestedNameSpecifier *NNS) {
assert(getLangOpts().CPlusPlus && "Only callable in C++");
assert(NNS->isDependent() && "Only dependent nested-name-specifier allowed");
if (!NNS->getAsType())
return nullptr;
QualType T = QualType(NNS->getAsType(), 0);
return ::getCurrentInstantiationOf(T, CurContext);
}
/// Require that the context specified by SS be complete.
///
/// If SS refers to a type, this routine checks whether the type is
/// complete enough (or can be made complete enough) for name lookup
/// into the DeclContext. A type that is not yet completed can be
/// considered "complete enough" if it is a class/struct/union/enum
/// that is currently being defined. Or, if we have a type that names
/// a class template specialization that is not a complete type, we
/// will attempt to instantiate that class template.
bool Sema::RequireCompleteDeclContext(CXXScopeSpec &SS,
DeclContext *DC) {
assert(DC && "given null context");
TagDecl *tag = dyn_cast<TagDecl>(DC);
// If this is a dependent type, then we consider it complete.
// FIXME: This is wrong; we should require a (visible) definition to
// exist in this case too.
if (!tag || tag->isDependentContext())
return false;
// Grab the tag definition, if there is one.
QualType type = Context.getTypeDeclType(tag);
tag = type->getAsTagDecl();
// If we're currently defining this type, then lookup into the
// type is okay: don't complain that it isn't complete yet.
if (tag->isBeingDefined())
return false;
SourceLocation loc = SS.getLastQualifierNameLoc();
if (loc.isInvalid()) loc = SS.getRange().getBegin();
// The type must be complete.
if (RequireCompleteType(loc, type, diag::err_incomplete_nested_name_spec,
SS.getRange())) {
SS.SetInvalid(SS.getRange());
return true;
}
if (auto *EnumD = dyn_cast<EnumDecl>(tag))
// Fixed enum types and scoped enum instantiations are complete, but they
// aren't valid as scopes until we see or instantiate their definition.
return RequireCompleteEnumDecl(EnumD, loc, &SS);
return false;
}
/// Require that the EnumDecl is completed with its enumerators defined or
/// instantiated. SS, if provided, is the ScopeRef parsed.
///
bool Sema::RequireCompleteEnumDecl(EnumDecl *EnumD, SourceLocation L,
CXXScopeSpec *SS) {
if (EnumD->isCompleteDefinition()) {
// If we know about the definition but it is not visible, complain.
NamedDecl *SuggestedDef = nullptr;
if (!hasVisibleDefinition(EnumD, &SuggestedDef,
/*OnlyNeedComplete*/false)) {
// If the user is going to see an error here, recover by making the
// definition visible.
bool TreatAsComplete = !isSFINAEContext();
diagnoseMissingImport(L, SuggestedDef, MissingImportKind::Definition,
/*Recover*/ TreatAsComplete);
return !TreatAsComplete;
}
return false;
}
// Try to instantiate the definition, if this is a specialization of an
// enumeration temploid.
if (EnumDecl *Pattern = EnumD->getInstantiatedFromMemberEnum()) {
MemberSpecializationInfo *MSI = EnumD->getMemberSpecializationInfo();
if (MSI->getTemplateSpecializationKind() != TSK_ExplicitSpecialization) {
if (InstantiateEnum(L, EnumD, Pattern,
getTemplateInstantiationArgs(EnumD),
TSK_ImplicitInstantiation)) {
if (SS)
SS->SetInvalid(SS->getRange());
return true;
}
return false;
}
}
if (SS) {
Diag(L, diag::err_incomplete_nested_name_spec)
<< QualType(EnumD->getTypeForDecl(), 0) << SS->getRange();
SS->SetInvalid(SS->getRange());
} else {
Diag(L, diag::err_incomplete_enum) << QualType(EnumD->getTypeForDecl(), 0);
Diag(EnumD->getLocation(), diag::note_declared_at);
}
return true;
}
bool Sema::ActOnCXXGlobalScopeSpecifier(SourceLocation CCLoc,
CXXScopeSpec &SS) {
SS.MakeGlobal(Context, CCLoc);
return false;
}
bool Sema::ActOnSuperScopeSpecifier(SourceLocation SuperLoc,
SourceLocation ColonColonLoc,
CXXScopeSpec &SS) {
CXXRecordDecl *RD = nullptr;
for (Scope *S = getCurScope(); S; S = S->getParent()) {
if (S->isFunctionScope()) {
if (CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(S->getEntity()))
RD = MD->getParent();
break;
}
if (S->isClassScope()) {
RD = cast<CXXRecordDecl>(S->getEntity());
break;
}
}
if (!RD) {
Diag(SuperLoc, diag::err_invalid_super_scope);
return true;
} else if (RD->isLambda()) {
Diag(SuperLoc, diag::err_super_in_lambda_unsupported);
return true;
} else if (RD->getNumBases() == 0) {
Diag(SuperLoc, diag::err_no_base_classes) << RD->getName();
return true;
}
SS.MakeSuper(Context, RD, SuperLoc, ColonColonLoc);
return false;
}
/// Determines whether the given declaration is an valid acceptable
/// result for name lookup of a nested-name-specifier.
/// \param SD Declaration checked for nested-name-specifier.
/// \param IsExtension If not null and the declaration is accepted as an
/// extension, the pointed variable is assigned true.
bool Sema::isAcceptableNestedNameSpecifier(const NamedDecl *SD,
bool *IsExtension) {
if (!SD)
return false;
SD = SD->getUnderlyingDecl();
// Namespace and namespace aliases are fine.
if (isa<NamespaceDecl>(SD))
return true;
if (!isa<TypeDecl>(SD))
return false;
// Determine whether we have a class (or, in C++11, an enum) or
// a typedef thereof. If so, build the nested-name-specifier.
QualType T = Context.getTypeDeclType(cast<TypeDecl>(SD));
if (T->isDependentType())
return true;
if (const TypedefNameDecl *TD = dyn_cast<TypedefNameDecl>(SD)) {
if (TD->getUnderlyingType()->isRecordType())
return true;
if (TD->getUnderlyingType()->isEnumeralType()) {
if (Context.getLangOpts().CPlusPlus11)
return true;
if (IsExtension)
*IsExtension = true;
}
} else if (isa<RecordDecl>(SD)) {
return true;
} else if (isa<EnumDecl>(SD)) {
if (Context.getLangOpts().CPlusPlus11)
return true;
if (IsExtension)
*IsExtension = true;
}
return false;
}
/// If the given nested-name-specifier begins with a bare identifier
/// (e.g., Base::), perform name lookup for that identifier as a
/// nested-name-specifier within the given scope, and return the result of that
/// name lookup.
NamedDecl *Sema::FindFirstQualifierInScope(Scope *S, NestedNameSpecifier *NNS) {
if (!S || !NNS)
return nullptr;
while (NNS->getPrefix())
NNS = NNS->getPrefix();
if (NNS->getKind() != NestedNameSpecifier::Identifier)
return nullptr;
LookupResult Found(*this, NNS->getAsIdentifier(), SourceLocation(),
LookupNestedNameSpecifierName);
LookupName(Found, S);
assert(!Found.isAmbiguous() && "Cannot handle ambiguities here yet");
if (!Found.isSingleResult())
return nullptr;
NamedDecl *Result = Found.getFoundDecl();
if (isAcceptableNestedNameSpecifier(Result))
return Result;
return nullptr;
}
bool Sema::isNonTypeNestedNameSpecifier(Scope *S, CXXScopeSpec &SS,
NestedNameSpecInfo &IdInfo) {
QualType ObjectType = GetTypeFromParser(IdInfo.ObjectType);
LookupResult Found(*this, IdInfo.Identifier, IdInfo.IdentifierLoc,
LookupNestedNameSpecifierName);
// Determine where to perform name lookup
DeclContext *LookupCtx = nullptr;
bool isDependent = false;
if (!ObjectType.isNull()) {
// This nested-name-specifier occurs in a member access expression, e.g.,
// x->B::f, and we are looking into the type of the object.
assert(!SS.isSet() && "ObjectType and scope specifier cannot coexist");
LookupCtx = computeDeclContext(ObjectType);
isDependent = ObjectType->isDependentType();
} else if (SS.isSet()) {
// This nested-name-specifier occurs after another nested-name-specifier,
// so long into the context associated with the prior nested-name-specifier.
LookupCtx = computeDeclContext(SS, false);
isDependent = isDependentScopeSpecifier(SS);
Found.setContextRange(SS.getRange());
}
if (LookupCtx) {
// Perform "qualified" name lookup into the declaration context we
// computed, which is either the type of the base of a member access
// expression or the declaration context associated with a prior
// nested-name-specifier.
// The declaration context must be complete.
if (!LookupCtx->isDependentContext() &&
RequireCompleteDeclContext(SS, LookupCtx))
return false;
LookupQualifiedName(Found, LookupCtx);
} else if (isDependent) {
return false;
} else {
LookupName(Found, S);
}
Found.suppressDiagnostics();
return Found.getAsSingle<NamespaceDecl>();
}
namespace {
// Callback to only accept typo corrections that can be a valid C++ member
// initializer: either a non-static field member or a base class.
class NestedNameSpecifierValidatorCCC final
: public CorrectionCandidateCallback {
public:
explicit NestedNameSpecifierValidatorCCC(Sema &SRef)
: SRef(SRef) {}
bool ValidateCandidate(const TypoCorrection &candidate) override {
return SRef.isAcceptableNestedNameSpecifier(candidate.getCorrectionDecl());
}
std::unique_ptr<CorrectionCandidateCallback> clone() override {
return std::make_unique<NestedNameSpecifierValidatorCCC>(*this);
}
private:
Sema &SRef;
};
}
/// Build a new nested-name-specifier for "identifier::", as described
/// by ActOnCXXNestedNameSpecifier.
///
/// \param S Scope in which the nested-name-specifier occurs.
/// \param IdInfo Parser information about an identifier in the
/// nested-name-spec.
/// \param EnteringContext If true, enter the context specified by the
/// nested-name-specifier.
/// \param SS Optional nested name specifier preceding the identifier.
/// \param ScopeLookupResult Provides the result of name lookup within the
/// scope of the nested-name-specifier that was computed at template
/// definition time.
/// \param ErrorRecoveryLookup Specifies if the method is called to improve
/// error recovery and what kind of recovery is performed.
/// \param IsCorrectedToColon If not null, suggestion of replace '::' -> ':'
/// are allowed. The bool value pointed by this parameter is set to
/// 'true' if the identifier is treated as if it was followed by ':',
/// not '::'.
/// \param OnlyNamespace If true, only considers namespaces in lookup.
///
/// This routine differs only slightly from ActOnCXXNestedNameSpecifier, in
/// that it contains an extra parameter \p ScopeLookupResult, which provides
/// the result of name lookup within the scope of the nested-name-specifier
/// that was computed at template definition time.
///
/// If ErrorRecoveryLookup is true, then this call is used to improve error
/// recovery. This means that it should not emit diagnostics, it should
/// just return true on failure. It also means it should only return a valid
/// scope if it *knows* that the result is correct. It should not return in a
/// dependent context, for example. Nor will it extend \p SS with the scope
/// specifier.
bool Sema::BuildCXXNestedNameSpecifier(Scope *S, NestedNameSpecInfo &IdInfo,
bool EnteringContext, CXXScopeSpec &SS,
NamedDecl *ScopeLookupResult,
bool ErrorRecoveryLookup,
bool *IsCorrectedToColon,
bool OnlyNamespace) {
if (IdInfo.Identifier->isEditorPlaceholder())
return true;
LookupResult Found(*this, IdInfo.Identifier, IdInfo.IdentifierLoc,
OnlyNamespace ? LookupNamespaceName
: LookupNestedNameSpecifierName);
QualType ObjectType = GetTypeFromParser(IdInfo.ObjectType);
// Determine where to perform name lookup
DeclContext *LookupCtx = nullptr;
bool isDependent = false;
if (IsCorrectedToColon)
*IsCorrectedToColon = false;
if (!ObjectType.isNull()) {
// This nested-name-specifier occurs in a member access expression, e.g.,
// x->B::f, and we are looking into the type of the object.
assert(!SS.isSet() && "ObjectType and scope specifier cannot coexist");
LookupCtx = computeDeclContext(ObjectType);
isDependent = ObjectType->isDependentType();
} else if (SS.isSet()) {
// This nested-name-specifier occurs after another nested-name-specifier,
// so look into the context associated with the prior nested-name-specifier.
LookupCtx = computeDeclContext(SS, EnteringContext);
isDependent = isDependentScopeSpecifier(SS);
Found.setContextRange(SS.getRange());
}
bool ObjectTypeSearchedInScope = false;
if (LookupCtx) {
// Perform "qualified" name lookup into the declaration context we
// computed, which is either the type of the base of a member access
// expression or the declaration context associated with a prior
// nested-name-specifier.
// The declaration context must be complete.
if (!LookupCtx->isDependentContext() &&
RequireCompleteDeclContext(SS, LookupCtx))
return true;
LookupQualifiedName(Found, LookupCtx);
if (!ObjectType.isNull() && Found.empty()) {
// C++ [basic.lookup.classref]p4:
// If the id-expression in a class member access is a qualified-id of
// the form
//
// class-name-or-namespace-name::...
//
// the class-name-or-namespace-name following the . or -> operator is
// looked up both in the context of the entire postfix-expression and in
// the scope of the class of the object expression. If the name is found
// only in the scope of the class of the object expression, the name
// shall refer to a class-name. If the name is found only in the
// context of the entire postfix-expression, the name shall refer to a
// class-name or namespace-name. [...]
//
// Qualified name lookup into a class will not find a namespace-name,
// so we do not need to diagnose that case specifically. However,
// this qualified name lookup may find nothing. In that case, perform
// unqualified name lookup in the given scope (if available) or
// reconstruct the result from when name lookup was performed at template
// definition time.
if (S)
LookupName(Found, S);
else if (ScopeLookupResult)
Found.addDecl(ScopeLookupResult);
ObjectTypeSearchedInScope = true;
}
} else if (!isDependent) {
// Perform unqualified name lookup in the current scope.
LookupName(Found, S);
}
if (Found.isAmbiguous())
return true;
// If we performed lookup into a dependent context and did not find anything,
// that's fine: just build a dependent nested-name-specifier.
if (Found.empty() && isDependent &&
!(LookupCtx && LookupCtx->isRecord() &&
(!cast<CXXRecordDecl>(LookupCtx)->hasDefinition() ||
!cast<CXXRecordDecl>(LookupCtx)->hasAnyDependentBases()))) {
// Don't speculate if we're just trying to improve error recovery.
if (ErrorRecoveryLookup)
return true;
// We were not able to compute the declaration context for a dependent
// base object type or prior nested-name-specifier, so this
// nested-name-specifier refers to an unknown specialization. Just build
// a dependent nested-name-specifier.
SS.Extend(Context, IdInfo.Identifier, IdInfo.IdentifierLoc, IdInfo.CCLoc);
return false;
}
if (Found.empty() && !ErrorRecoveryLookup) {
// If identifier is not found as class-name-or-namespace-name, but is found
// as other entity, don't look for typos.
LookupResult R(*this, Found.getLookupNameInfo(), LookupOrdinaryName);
if (LookupCtx)
LookupQualifiedName(R, LookupCtx);
else if (S && !isDependent)
LookupName(R, S);
if (!R.empty()) {
// Don't diagnose problems with this speculative lookup.
R.suppressDiagnostics();
// The identifier is found in ordinary lookup. If correction to colon is
// allowed, suggest replacement to ':'.
if (IsCorrectedToColon) {
*IsCorrectedToColon = true;
Diag(IdInfo.CCLoc, diag::err_nested_name_spec_is_not_class)
<< IdInfo.Identifier << getLangOpts().CPlusPlus
<< FixItHint::CreateReplacement(IdInfo.CCLoc, ":");
if (NamedDecl *ND = R.getAsSingle<NamedDecl>())
Diag(ND->getLocation(), diag::note_declared_at);
return true;
}
// Replacement '::' -> ':' is not allowed, just issue respective error.
Diag(R.getNameLoc(), OnlyNamespace
? unsigned(diag::err_expected_namespace_name)
: unsigned(diag::err_expected_class_or_namespace))
<< IdInfo.Identifier << getLangOpts().CPlusPlus;
if (NamedDecl *ND = R.getAsSingle<NamedDecl>())
Diag(ND->getLocation(), diag::note_entity_declared_at)
<< IdInfo.Identifier;
return true;
}
}
if (Found.empty() && !ErrorRecoveryLookup && !getLangOpts().MSVCCompat) {
// We haven't found anything, and we're not recovering from a
// different kind of error, so look for typos.
DeclarationName Name = Found.getLookupName();
Found.clear();
NestedNameSpecifierValidatorCCC CCC(*this);
if (TypoCorrection Corrected = CorrectTypo(
Found.getLookupNameInfo(), Found.getLookupKind(), S, &SS, CCC,
CTK_ErrorRecovery, LookupCtx, EnteringContext)) {
if (LookupCtx) {
bool DroppedSpecifier =
Corrected.WillReplaceSpecifier() &&
Name.getAsString() == Corrected.getAsString(getLangOpts());
if (DroppedSpecifier)
SS.clear();
diagnoseTypo(Corrected, PDiag(diag::err_no_member_suggest)
<< Name << LookupCtx << DroppedSpecifier
<< SS.getRange());
} else
diagnoseTypo(Corrected, PDiag(diag::err_undeclared_var_use_suggest)
<< Name);
if (Corrected.getCorrectionSpecifier())
SS.MakeTrivial(Context, Corrected.getCorrectionSpecifier(),
SourceRange(Found.getNameLoc()));
if (NamedDecl *ND = Corrected.getFoundDecl())
Found.addDecl(ND);
Found.setLookupName(Corrected.getCorrection());
} else {
Found.setLookupName(IdInfo.Identifier);
}
}
NamedDecl *SD =
Found.isSingleResult() ? Found.getRepresentativeDecl() : nullptr;
bool IsExtension = false;
bool AcceptSpec = isAcceptableNestedNameSpecifier(SD, &IsExtension);
if (!AcceptSpec && IsExtension) {
AcceptSpec = true;
Diag(IdInfo.IdentifierLoc, diag::ext_nested_name_spec_is_enum);
}
if (AcceptSpec) {
if (!ObjectType.isNull() && !ObjectTypeSearchedInScope &&
!getLangOpts().CPlusPlus11) {
// C++03 [basic.lookup.classref]p4:
// [...] If the name is found in both contexts, the
// class-name-or-namespace-name shall refer to the same entity.
//
// We already found the name in the scope of the object. Now, look
// into the current scope (the scope of the postfix-expression) to
// see if we can find the same name there. As above, if there is no
// scope, reconstruct the result from the template instantiation itself.
//
// Note that C++11 does *not* perform this redundant lookup.
NamedDecl *OuterDecl;
if (S) {
LookupResult FoundOuter(*this, IdInfo.Identifier, IdInfo.IdentifierLoc,
LookupNestedNameSpecifierName);
LookupName(FoundOuter, S);
OuterDecl = FoundOuter.getAsSingle<NamedDecl>();
} else
OuterDecl = ScopeLookupResult;
if (isAcceptableNestedNameSpecifier(OuterDecl) &&
OuterDecl->getCanonicalDecl() != SD->getCanonicalDecl() &&
(!isa<TypeDecl>(OuterDecl) || !isa<TypeDecl>(SD) ||
!Context.hasSameType(
Context.getTypeDeclType(cast<TypeDecl>(OuterDecl)),
Context.getTypeDeclType(cast<TypeDecl>(SD))))) {
if (ErrorRecoveryLookup)
return true;
Diag(IdInfo.IdentifierLoc,
diag::err_nested_name_member_ref_lookup_ambiguous)
<< IdInfo.Identifier;
Diag(SD->getLocation(), diag::note_ambig_member_ref_object_type)
<< ObjectType;
Diag(OuterDecl->getLocation(), diag::note_ambig_member_ref_scope);
// Fall through so that we'll pick the name we found in the object
// type, since that's probably what the user wanted anyway.
}
}
if (auto *TD = dyn_cast_or_null<TypedefNameDecl>(SD))
MarkAnyDeclReferenced(TD->getLocation(), TD, /*OdrUse=*/false);
// If we're just performing this lookup for error-recovery purposes,
// don't extend the nested-name-specifier. Just return now.
if (ErrorRecoveryLookup)
return false;
// The use of a nested name specifier may trigger deprecation warnings.
DiagnoseUseOfDecl(SD, IdInfo.CCLoc);
if (NamespaceDecl *Namespace = dyn_cast<NamespaceDecl>(SD)) {
SS.Extend(Context, Namespace, IdInfo.IdentifierLoc, IdInfo.CCLoc);
return false;
}
if (NamespaceAliasDecl *Alias = dyn_cast<NamespaceAliasDecl>(SD)) {
SS.Extend(Context, Alias, IdInfo.IdentifierLoc, IdInfo.CCLoc);
return false;
}
QualType T =
Context.getTypeDeclType(cast<TypeDecl>(SD->getUnderlyingDecl()));
if (T->isEnumeralType())
Diag(IdInfo.IdentifierLoc, diag::warn_cxx98_compat_enum_nested_name_spec);
TypeLocBuilder TLB;
if (const auto *USD = dyn_cast<UsingShadowDecl>(SD)) {
T = Context.getUsingType(USD, T);
TLB.pushTypeSpec(T).setNameLoc(IdInfo.IdentifierLoc);
} else if (isa<InjectedClassNameType>(T)) {
InjectedClassNameTypeLoc InjectedTL
= TLB.push<InjectedClassNameTypeLoc>(T);
InjectedTL.setNameLoc(IdInfo.IdentifierLoc);
} else if (isa<RecordType>(T)) {
RecordTypeLoc RecordTL = TLB.push<RecordTypeLoc>(T);
RecordTL.setNameLoc(IdInfo.IdentifierLoc);
} else if (isa<TypedefType>(T)) {
TypedefTypeLoc TypedefTL = TLB.push<TypedefTypeLoc>(T);
TypedefTL.setNameLoc(IdInfo.IdentifierLoc);
} else if (isa<EnumType>(T)) {
EnumTypeLoc EnumTL = TLB.push<EnumTypeLoc>(T);
EnumTL.setNameLoc(IdInfo.IdentifierLoc);
} else if (isa<TemplateTypeParmType>(T)) {
TemplateTypeParmTypeLoc TemplateTypeTL
= TLB.push<TemplateTypeParmTypeLoc>(T);
TemplateTypeTL.setNameLoc(IdInfo.IdentifierLoc);
} else if (isa<UnresolvedUsingType>(T)) {
UnresolvedUsingTypeLoc UnresolvedTL
= TLB.push<UnresolvedUsingTypeLoc>(T);
UnresolvedTL.setNameLoc(IdInfo.IdentifierLoc);
} else if (isa<SubstTemplateTypeParmType>(T)) {
SubstTemplateTypeParmTypeLoc TL
= TLB.push<SubstTemplateTypeParmTypeLoc>(T);
TL.setNameLoc(IdInfo.IdentifierLoc);
} else if (isa<SubstTemplateTypeParmPackType>(T)) {
SubstTemplateTypeParmPackTypeLoc TL
= TLB.push<SubstTemplateTypeParmPackTypeLoc>(T);
TL.setNameLoc(IdInfo.IdentifierLoc);
} else {
llvm_unreachable("Unhandled TypeDecl node in nested-name-specifier");
}
SS.Extend(Context, SourceLocation(), TLB.getTypeLocInContext(Context, T),
IdInfo.CCLoc);
return false;
}
// Otherwise, we have an error case. If we don't want diagnostics, just
// return an error now.
if (ErrorRecoveryLookup)
return true;
// If we didn't find anything during our lookup, try again with
// ordinary name lookup, which can help us produce better error
// messages.
if (Found.empty()) {
Found.clear(LookupOrdinaryName);
LookupName(Found, S);
}
// In Microsoft mode, if we are within a templated function and we can't
// resolve Identifier, then extend the SS with Identifier. This will have
// the effect of resolving Identifier during template instantiation.
// The goal is to be able to resolve a function call whose
// nested-name-specifier is located inside a dependent base class.
// Example:
//
// class C {
// public:
// static void foo2() { }
// };
// template <class T> class A { public: typedef C D; };
//
// template <class T> class B : public A<T> {
// public:
// void foo() { D::foo2(); }
// };
if (getLangOpts().MSVCCompat) {
DeclContext *DC = LookupCtx ? LookupCtx : CurContext;
if (DC->isDependentContext() && DC->isFunctionOrMethod()) {
CXXRecordDecl *ContainingClass = dyn_cast<CXXRecordDecl>(DC->getParent());
if (ContainingClass && ContainingClass->hasAnyDependentBases()) {
Diag(IdInfo.IdentifierLoc,
diag::ext_undeclared_unqual_id_with_dependent_base)
<< IdInfo.Identifier << ContainingClass;
SS.Extend(Context, IdInfo.Identifier, IdInfo.IdentifierLoc,
IdInfo.CCLoc);
return false;
}
}
}
if (!Found.empty()) {
if (TypeDecl *TD = Found.getAsSingle<TypeDecl>()) {
Diag(IdInfo.IdentifierLoc, diag::err_expected_class_or_namespace)
<< Context.getTypeDeclType(TD) << getLangOpts().CPlusPlus;
} else if (Found.getAsSingle<TemplateDecl>()) {
ParsedType SuggestedType;
DiagnoseUnknownTypeName(IdInfo.Identifier, IdInfo.IdentifierLoc, S, &SS,
SuggestedType);
} else {
Diag(IdInfo.IdentifierLoc, diag::err_expected_class_or_namespace)
<< IdInfo.Identifier << getLangOpts().CPlusPlus;
if (NamedDecl *ND = Found.getAsSingle<NamedDecl>())
Diag(ND->getLocation(), diag::note_entity_declared_at)
<< IdInfo.Identifier;
}
} else if (SS.isSet())
Diag(IdInfo.IdentifierLoc, diag::err_no_member) << IdInfo.Identifier
<< LookupCtx << SS.getRange();
else
Diag(IdInfo.IdentifierLoc, diag::err_undeclared_var_use)
<< IdInfo.Identifier;
return true;
}
bool Sema::ActOnCXXNestedNameSpecifier(Scope *S, NestedNameSpecInfo &IdInfo,
bool EnteringContext, CXXScopeSpec &SS,
bool *IsCorrectedToColon,
bool OnlyNamespace) {
if (SS.isInvalid())
return true;
return BuildCXXNestedNameSpecifier(S, IdInfo, EnteringContext, SS,
/*ScopeLookupResult=*/nullptr, false,
IsCorrectedToColon, OnlyNamespace);
}
bool Sema::ActOnCXXNestedNameSpecifierDecltype(CXXScopeSpec &SS,
const DeclSpec &DS,
SourceLocation ColonColonLoc) {
if (SS.isInvalid() || DS.getTypeSpecType() == DeclSpec::TST_error)
return true;
assert(DS.getTypeSpecType() == DeclSpec::TST_decltype);
QualType T = BuildDecltypeType(DS.getRepAsExpr());
if (T.isNull())
return true;
if (!T->isDependentType() && !T->getAs<TagType>()) {
Diag(DS.getTypeSpecTypeLoc(), diag::err_expected_class_or_namespace)
<< T << getLangOpts().CPlusPlus;
return true;
}
TypeLocBuilder TLB;
DecltypeTypeLoc DecltypeTL = TLB.push<DecltypeTypeLoc>(T);
DecltypeTL.setDecltypeLoc(DS.getTypeSpecTypeLoc());
DecltypeTL.setRParenLoc(DS.getTypeofParensRange().getEnd());
SS.Extend(Context, SourceLocation(), TLB.getTypeLocInContext(Context, T),
ColonColonLoc);
return false;
}
/// IsInvalidUnlessNestedName - This method is used for error recovery
/// purposes to determine whether the specified identifier is only valid as
/// a nested name specifier, for example a namespace name. It is
/// conservatively correct to always return false from this method.
///
/// The arguments are the same as those passed to ActOnCXXNestedNameSpecifier.
bool Sema::IsInvalidUnlessNestedName(Scope *S, CXXScopeSpec &SS,
NestedNameSpecInfo &IdInfo,
bool EnteringContext) {
if (SS.isInvalid())
return false;
return !BuildCXXNestedNameSpecifier(S, IdInfo, EnteringContext, SS,
/*ScopeLookupResult=*/nullptr, true);
}
bool Sema::ActOnCXXNestedNameSpecifier(Scope *S,
CXXScopeSpec &SS,
SourceLocation TemplateKWLoc,
TemplateTy OpaqueTemplate,
SourceLocation TemplateNameLoc,
SourceLocation LAngleLoc,
ASTTemplateArgsPtr TemplateArgsIn,
SourceLocation RAngleLoc,
SourceLocation CCLoc,
bool EnteringContext) {
if (SS.isInvalid())
return true;
TemplateName Template = OpaqueTemplate.get();
// Translate the parser's template argument list in our AST format.
TemplateArgumentListInfo TemplateArgs(LAngleLoc, RAngleLoc);
translateTemplateArguments(TemplateArgsIn, TemplateArgs);
DependentTemplateName *DTN = Template.getAsDependentTemplateName();
if (DTN && DTN->isIdentifier()) {
// Handle a dependent template specialization for which we cannot resolve
// the template name.
assert(DTN->getQualifier() == SS.getScopeRep());
QualType T = Context.getDependentTemplateSpecializationType(ETK_None,
DTN->getQualifier(),
DTN->getIdentifier(),
TemplateArgs);
// Create source-location information for this type.
TypeLocBuilder Builder;
DependentTemplateSpecializationTypeLoc SpecTL
= Builder.push<DependentTemplateSpecializationTypeLoc>(T);
SpecTL.setElaboratedKeywordLoc(SourceLocation());
SpecTL.setQualifierLoc(SS.getWithLocInContext(Context));
SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
SpecTL.setTemplateNameLoc(TemplateNameLoc);
SpecTL.setLAngleLoc(LAngleLoc);
SpecTL.setRAngleLoc(RAngleLoc);
for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I)
SpecTL.setArgLocInfo(I, TemplateArgs[I].getLocInfo());
SS.Extend(Context, TemplateKWLoc, Builder.getTypeLocInContext(Context, T),
CCLoc);
return false;
}
// If we assumed an undeclared identifier was a template name, try to
// typo-correct it now.
if (Template.getAsAssumedTemplateName() &&
resolveAssumedTemplateNameAsType(S, Template, TemplateNameLoc))
return true;
TemplateDecl *TD = Template.getAsTemplateDecl();
if (Template.getAsOverloadedTemplate() || DTN ||
isa<FunctionTemplateDecl>(TD) || isa<VarTemplateDecl>(TD)) {
SourceRange R(TemplateNameLoc, RAngleLoc);
if (SS.getRange().isValid())
R.setBegin(SS.getRange().getBegin());
Diag(CCLoc, diag::err_non_type_template_in_nested_name_specifier)
<< (TD && isa<VarTemplateDecl>(TD)) << Template << R;
NoteAllFoundTemplates(Template);
return true;
}
// We were able to resolve the template name to an actual template.
// Build an appropriate nested-name-specifier.
QualType T = CheckTemplateIdType(Template, TemplateNameLoc, TemplateArgs);
if (T.isNull())
return true;
// Alias template specializations can produce types which are not valid
// nested name specifiers.
if (!T->isDependentType() && !T->getAs<TagType>()) {
Diag(TemplateNameLoc, diag::err_nested_name_spec_non_tag) << T;
NoteAllFoundTemplates(Template);
return true;
}
// Provide source-location information for the template specialization type.
TypeLocBuilder Builder;
TemplateSpecializationTypeLoc SpecTL
= Builder.push<TemplateSpecializationTypeLoc>(T);
SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
SpecTL.setTemplateNameLoc(TemplateNameLoc);
SpecTL.setLAngleLoc(LAngleLoc);
SpecTL.setRAngleLoc(RAngleLoc);
for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I)
SpecTL.setArgLocInfo(I, TemplateArgs[I].getLocInfo());
SS.Extend(Context, TemplateKWLoc, Builder.getTypeLocInContext(Context, T),
CCLoc);
return false;
}
namespace {
/// A structure that stores a nested-name-specifier annotation,
/// including both the nested-name-specifier
struct NestedNameSpecifierAnnotation {
NestedNameSpecifier *NNS;
};
}
void *Sema::SaveNestedNameSpecifierAnnotation(CXXScopeSpec &SS) {
if (SS.isEmpty() || SS.isInvalid())
return nullptr;
void *Mem = Context.Allocate(
(sizeof(NestedNameSpecifierAnnotation) + SS.location_size()),
alignof(NestedNameSpecifierAnnotation));
NestedNameSpecifierAnnotation *Annotation
= new (Mem) NestedNameSpecifierAnnotation;
Annotation->NNS = SS.getScopeRep();
memcpy(Annotation + 1, SS.location_data(), SS.location_size());
return Annotation;
}
void Sema::RestoreNestedNameSpecifierAnnotation(void *AnnotationPtr,
SourceRange AnnotationRange,
CXXScopeSpec &SS) {
if (!AnnotationPtr) {
SS.SetInvalid(AnnotationRange);
return;
}
NestedNameSpecifierAnnotation *Annotation
= static_cast<NestedNameSpecifierAnnotation *>(AnnotationPtr);
SS.Adopt(NestedNameSpecifierLoc(Annotation->NNS, Annotation + 1));
}
bool Sema::ShouldEnterDeclaratorScope(Scope *S, const CXXScopeSpec &SS) {
assert(SS.isSet() && "Parser passed invalid CXXScopeSpec.");
// Don't enter a declarator context when the current context is an Objective-C
// declaration.
if (isa<ObjCContainerDecl>(CurContext) || isa<ObjCMethodDecl>(CurContext))
return false;
NestedNameSpecifier *Qualifier = SS.getScopeRep();
// There are only two places a well-formed program may qualify a
// declarator: first, when defining a namespace or class member
// out-of-line, and second, when naming an explicitly-qualified
// friend function. The latter case is governed by
// C++03 [basic.lookup.unqual]p10:
// In a friend declaration naming a member function, a name used
// in the function declarator and not part of a template-argument
// in a template-id is first looked up in the scope of the member
// function's class. If it is not found, or if the name is part of
// a template-argument in a template-id, the look up is as
// described for unqualified names in the definition of the class
// granting friendship.
// i.e. we don't push a scope unless it's a class member.
switch (Qualifier->getKind()) {
case NestedNameSpecifier::Global:
case NestedNameSpecifier::Namespace:
case NestedNameSpecifier::NamespaceAlias:
// These are always namespace scopes. We never want to enter a
// namespace scope from anything but a file context.
return CurContext->getRedeclContext()->isFileContext();
case NestedNameSpecifier::Identifier:
case NestedNameSpecifier::TypeSpec:
case NestedNameSpecifier::TypeSpecWithTemplate:
case NestedNameSpecifier::Super:
// These are never namespace scopes.
return true;
}
llvm_unreachable("Invalid NestedNameSpecifier::Kind!");
}
/// ActOnCXXEnterDeclaratorScope - Called when a C++ scope specifier (global
/// scope or nested-name-specifier) is parsed, part of a declarator-id.
/// After this method is called, according to [C++ 3.4.3p3], names should be
/// looked up in the declarator-id's scope, until the declarator is parsed and
/// ActOnCXXExitDeclaratorScope is called.
/// The 'SS' should be a non-empty valid CXXScopeSpec.
bool Sema::ActOnCXXEnterDeclaratorScope(Scope *S, CXXScopeSpec &SS) {
assert(SS.isSet() && "Parser passed invalid CXXScopeSpec.");
if (SS.isInvalid()) return true;
DeclContext *DC = computeDeclContext(SS, true);
if (!DC) return true;
// Before we enter a declarator's context, we need to make sure that
// it is a complete declaration context.
if (!DC->isDependentContext() && RequireCompleteDeclContext(SS, DC))
return true;
EnterDeclaratorContext(S, DC);
// Rebuild the nested name specifier for the new scope.
if (DC->isDependentContext())
RebuildNestedNameSpecifierInCurrentInstantiation(SS);
return false;
}
/// ActOnCXXExitDeclaratorScope - Called when a declarator that previously
/// invoked ActOnCXXEnterDeclaratorScope(), is finished. 'SS' is the same
/// CXXScopeSpec that was passed to ActOnCXXEnterDeclaratorScope as well.
/// Used to indicate that names should revert to being looked up in the
/// defining scope.
void Sema::ActOnCXXExitDeclaratorScope(Scope *S, const CXXScopeSpec &SS) {
assert(SS.isSet() && "Parser passed invalid CXXScopeSpec.");
if (SS.isInvalid())
return;
assert(!SS.isInvalid() && computeDeclContext(SS, true) &&
"exiting declarator scope we never really entered");
ExitDeclaratorContext(S);
}