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SemaDecl.cpp
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SemaDecl.cpp
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//===--- SemaDecl.cpp - Semantic Analysis for Declarations ----------------===//
//
// 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 semantic analysis for declarations.
//
//===----------------------------------------------------------------------===//
#include "TypeLocBuilder.h"
#include "clang/AST/ASTConsumer.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/ASTLambda.h"
#include "clang/AST/CXXInheritance.h"
#include "clang/AST/CharUnits.h"
#include "clang/AST/CommentDiagnostic.h"
#include "clang/AST/DeclCXX.h"
#include "clang/AST/DeclObjC.h"
#include "clang/AST/DeclTemplate.h"
#include "clang/AST/EvaluatedExprVisitor.h"
#include "clang/AST/Expr.h"
#include "clang/AST/ExprCXX.h"
#include "clang/AST/NonTrivialTypeVisitor.h"
#include "clang/AST/StmtCXX.h"
#include "clang/Basic/Builtins.h"
#include "clang/Basic/PartialDiagnostic.h"
#include "clang/Basic/SourceManager.h"
#include "clang/Basic/TargetInfo.h"
#include "clang/Lex/HeaderSearch.h" // TODO: Sema shouldn't depend on Lex
#include "clang/Lex/Lexer.h" // TODO: Extract static functions to fix layering.
#include "clang/Lex/ModuleLoader.h" // TODO: Sema shouldn't depend on Lex
#include "clang/Lex/Preprocessor.h" // Included for isCodeCompletionEnabled()
#include "clang/Sema/CXXFieldCollector.h"
#include "clang/Sema/DeclSpec.h"
#include "clang/Sema/DelayedDiagnostic.h"
#include "clang/Sema/Initialization.h"
#include "clang/Sema/Lookup.h"
#include "clang/Sema/ParsedTemplate.h"
#include "clang/Sema/Scope.h"
#include "clang/Sema/ScopeInfo.h"
#include "clang/Sema/SemaInternal.h"
#include "clang/Sema/Template.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/Triple.h"
#include <algorithm>
#include <cstring>
#include <functional>
#include <unordered_map>
using namespace clang;
using namespace sema;
Sema::DeclGroupPtrTy Sema::ConvertDeclToDeclGroup(Decl *Ptr, Decl *OwnedType) {
if (OwnedType) {
Decl *Group[2] = { OwnedType, Ptr };
return DeclGroupPtrTy::make(DeclGroupRef::Create(Context, Group, 2));
}
return DeclGroupPtrTy::make(DeclGroupRef(Ptr));
}
namespace {
class TypeNameValidatorCCC final : public CorrectionCandidateCallback {
public:
TypeNameValidatorCCC(bool AllowInvalid, bool WantClass = false,
bool AllowTemplates = false,
bool AllowNonTemplates = true)
: AllowInvalidDecl(AllowInvalid), WantClassName(WantClass),
AllowTemplates(AllowTemplates), AllowNonTemplates(AllowNonTemplates) {
WantExpressionKeywords = false;
WantCXXNamedCasts = false;
WantRemainingKeywords = false;
}
bool ValidateCandidate(const TypoCorrection &candidate) override {
if (NamedDecl *ND = candidate.getCorrectionDecl()) {
if (!AllowInvalidDecl && ND->isInvalidDecl())
return false;
if (getAsTypeTemplateDecl(ND))
return AllowTemplates;
bool IsType = isa<TypeDecl>(ND) || isa<ObjCInterfaceDecl>(ND);
if (!IsType)
return false;
if (AllowNonTemplates)
return true;
// An injected-class-name of a class template (specialization) is valid
// as a template or as a non-template.
if (AllowTemplates) {
auto *RD = dyn_cast<CXXRecordDecl>(ND);
if (!RD || !RD->isInjectedClassName())
return false;
RD = cast<CXXRecordDecl>(RD->getDeclContext());
return RD->getDescribedClassTemplate() ||
isa<ClassTemplateSpecializationDecl>(RD);
}
return false;
}
return !WantClassName && candidate.isKeyword();
}
std::unique_ptr<CorrectionCandidateCallback> clone() override {
return std::make_unique<TypeNameValidatorCCC>(*this);
}
private:
bool AllowInvalidDecl;
bool WantClassName;
bool AllowTemplates;
bool AllowNonTemplates;
};
} // end anonymous namespace
/// Determine whether the token kind starts a simple-type-specifier.
bool Sema::isSimpleTypeSpecifier(tok::TokenKind Kind) const {
switch (Kind) {
// FIXME: Take into account the current language when deciding whether a
// token kind is a valid type specifier
case tok::kw_short:
case tok::kw_long:
case tok::kw___int64:
case tok::kw___int128:
case tok::kw_signed:
case tok::kw_unsigned:
case tok::kw_void:
case tok::kw_char:
case tok::kw_int:
case tok::kw_half:
case tok::kw_float:
case tok::kw_double:
case tok::kw___bf16:
case tok::kw__Float16:
case tok::kw___float128:
case tok::kw_wchar_t:
case tok::kw_bool:
case tok::kw___underlying_type:
case tok::kw___auto_type:
return true;
case tok::annot_typename:
case tok::kw_char16_t:
case tok::kw_char32_t:
case tok::kw_typeof:
case tok::annot_decltype:
case tok::kw_decltype:
return getLangOpts().CPlusPlus;
case tok::kw_char8_t:
return getLangOpts().Char8;
default:
break;
}
return false;
}
namespace {
enum class UnqualifiedTypeNameLookupResult {
NotFound,
FoundNonType,
FoundType
};
} // end anonymous namespace
/// Tries to perform unqualified lookup of the type decls in bases for
/// dependent class.
/// \return \a NotFound if no any decls is found, \a FoundNotType if found not a
/// type decl, \a FoundType if only type decls are found.
static UnqualifiedTypeNameLookupResult
lookupUnqualifiedTypeNameInBase(Sema &S, const IdentifierInfo &II,
SourceLocation NameLoc,
const CXXRecordDecl *RD) {
if (!RD->hasDefinition())
return UnqualifiedTypeNameLookupResult::NotFound;
// Look for type decls in base classes.
UnqualifiedTypeNameLookupResult FoundTypeDecl =
UnqualifiedTypeNameLookupResult::NotFound;
for (const auto &Base : RD->bases()) {
const CXXRecordDecl *BaseRD = nullptr;
if (auto *BaseTT = Base.getType()->getAs<TagType>())
BaseRD = BaseTT->getAsCXXRecordDecl();
else if (auto *TST = Base.getType()->getAs<TemplateSpecializationType>()) {
// Look for type decls in dependent base classes that have known primary
// templates.
if (!TST || !TST->isDependentType())
continue;
auto *TD = TST->getTemplateName().getAsTemplateDecl();
if (!TD)
continue;
if (auto *BasePrimaryTemplate =
dyn_cast_or_null<CXXRecordDecl>(TD->getTemplatedDecl())) {
if (BasePrimaryTemplate->getCanonicalDecl() != RD->getCanonicalDecl())
BaseRD = BasePrimaryTemplate;
else if (auto *CTD = dyn_cast<ClassTemplateDecl>(TD)) {
if (const ClassTemplatePartialSpecializationDecl *PS =
CTD->findPartialSpecialization(Base.getType()))
if (PS->getCanonicalDecl() != RD->getCanonicalDecl())
BaseRD = PS;
}
}
}
if (BaseRD) {
for (NamedDecl *ND : BaseRD->lookup(&II)) {
if (!isa<TypeDecl>(ND))
return UnqualifiedTypeNameLookupResult::FoundNonType;
FoundTypeDecl = UnqualifiedTypeNameLookupResult::FoundType;
}
if (FoundTypeDecl == UnqualifiedTypeNameLookupResult::NotFound) {
switch (lookupUnqualifiedTypeNameInBase(S, II, NameLoc, BaseRD)) {
case UnqualifiedTypeNameLookupResult::FoundNonType:
return UnqualifiedTypeNameLookupResult::FoundNonType;
case UnqualifiedTypeNameLookupResult::FoundType:
FoundTypeDecl = UnqualifiedTypeNameLookupResult::FoundType;
break;
case UnqualifiedTypeNameLookupResult::NotFound:
break;
}
}
}
}
return FoundTypeDecl;
}
static ParsedType recoverFromTypeInKnownDependentBase(Sema &S,
const IdentifierInfo &II,
SourceLocation NameLoc) {
// Lookup in the parent class template context, if any.
const CXXRecordDecl *RD = nullptr;
UnqualifiedTypeNameLookupResult FoundTypeDecl =
UnqualifiedTypeNameLookupResult::NotFound;
for (DeclContext *DC = S.CurContext;
DC && FoundTypeDecl == UnqualifiedTypeNameLookupResult::NotFound;
DC = DC->getParent()) {
// Look for type decls in dependent base classes that have known primary
// templates.
RD = dyn_cast<CXXRecordDecl>(DC);
if (RD && RD->getDescribedClassTemplate())
FoundTypeDecl = lookupUnqualifiedTypeNameInBase(S, II, NameLoc, RD);
}
if (FoundTypeDecl != UnqualifiedTypeNameLookupResult::FoundType)
return nullptr;
// We found some types in dependent base classes. Recover as if the user
// wrote 'typename MyClass::II' instead of 'II'. We'll fully resolve the
// lookup during template instantiation.
S.Diag(NameLoc, diag::ext_found_in_dependent_base) << &II;
ASTContext &Context = S.Context;
auto *NNS = NestedNameSpecifier::Create(Context, nullptr, false,
cast<Type>(Context.getRecordType(RD)));
QualType T = Context.getDependentNameType(ETK_Typename, NNS, &II);
CXXScopeSpec SS;
SS.MakeTrivial(Context, NNS, SourceRange(NameLoc));
TypeLocBuilder Builder;
DependentNameTypeLoc DepTL = Builder.push<DependentNameTypeLoc>(T);
DepTL.setNameLoc(NameLoc);
DepTL.setElaboratedKeywordLoc(SourceLocation());
DepTL.setQualifierLoc(SS.getWithLocInContext(Context));
return S.CreateParsedType(T, Builder.getTypeSourceInfo(Context, T));
}
/// If the identifier refers to a type name within this scope,
/// return the declaration of that type.
///
/// This routine performs ordinary name lookup of the identifier II
/// within the given scope, with optional C++ scope specifier SS, to
/// determine whether the name refers to a type. If so, returns an
/// opaque pointer (actually a QualType) corresponding to that
/// type. Otherwise, returns NULL.
ParsedType Sema::getTypeName(const IdentifierInfo &II, SourceLocation NameLoc,
Scope *S, CXXScopeSpec *SS,
bool isClassName, bool HasTrailingDot,
ParsedType ObjectTypePtr,
bool IsCtorOrDtorName,
bool WantNontrivialTypeSourceInfo,
bool IsClassTemplateDeductionContext,
IdentifierInfo **CorrectedII) {
// FIXME: Consider allowing this outside C++1z mode as an extension.
bool AllowDeducedTemplate = IsClassTemplateDeductionContext &&
getLangOpts().CPlusPlus17 && !IsCtorOrDtorName &&
!isClassName && !HasTrailingDot;
// Determine where we will perform name lookup.
DeclContext *LookupCtx = nullptr;
if (ObjectTypePtr) {
QualType ObjectType = ObjectTypePtr.get();
if (ObjectType->isRecordType())
LookupCtx = computeDeclContext(ObjectType);
} else if (SS && SS->isNotEmpty()) {
LookupCtx = computeDeclContext(*SS, false);
if (!LookupCtx) {
if (isDependentScopeSpecifier(*SS)) {
// C++ [temp.res]p3:
// A qualified-id that refers to a type and in which the
// nested-name-specifier depends on a template-parameter (14.6.2)
// shall be prefixed by the keyword typename to indicate that the
// qualified-id denotes a type, forming an
// elaborated-type-specifier (7.1.5.3).
//
// We therefore do not perform any name lookup if the result would
// refer to a member of an unknown specialization.
if (!isClassName && !IsCtorOrDtorName)
return nullptr;
// We know from the grammar that this name refers to a type,
// so build a dependent node to describe the type.
if (WantNontrivialTypeSourceInfo)
return ActOnTypenameType(S, SourceLocation(), *SS, II, NameLoc).get();
NestedNameSpecifierLoc QualifierLoc = SS->getWithLocInContext(Context);
QualType T = CheckTypenameType(ETK_None, SourceLocation(), QualifierLoc,
II, NameLoc);
return ParsedType::make(T);
}
return nullptr;
}
if (!LookupCtx->isDependentContext() &&
RequireCompleteDeclContext(*SS, LookupCtx))
return nullptr;
}
// FIXME: LookupNestedNameSpecifierName isn't the right kind of
// lookup for class-names.
LookupNameKind Kind = isClassName ? LookupNestedNameSpecifierName :
LookupOrdinaryName;
LookupResult Result(*this, &II, NameLoc, Kind);
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.
LookupQualifiedName(Result, LookupCtx);
if (ObjectTypePtr && Result.empty()) {
// C++ [basic.lookup.classref]p3:
// If the unqualified-id is ~type-name, the type-name is looked up
// in the context of the entire postfix-expression. If the type T of
// the object expression is of a class type C, the type-name is also
// looked up in the scope of class C. At least one of the lookups shall
// find a name that refers to (possibly cv-qualified) T.
LookupName(Result, S);
}
} else {
// Perform unqualified name lookup.
LookupName(Result, S);
// For unqualified lookup in a class template in MSVC mode, look into
// dependent base classes where the primary class template is known.
if (Result.empty() && getLangOpts().MSVCCompat && (!SS || SS->isEmpty())) {
if (ParsedType TypeInBase =
recoverFromTypeInKnownDependentBase(*this, II, NameLoc))
return TypeInBase;
}
}
NamedDecl *IIDecl = nullptr;
switch (Result.getResultKind()) {
case LookupResult::NotFound:
case LookupResult::NotFoundInCurrentInstantiation:
if (CorrectedII) {
TypeNameValidatorCCC CCC(/*AllowInvalid=*/true, isClassName,
AllowDeducedTemplate);
TypoCorrection Correction = CorrectTypo(Result.getLookupNameInfo(), Kind,
S, SS, CCC, CTK_ErrorRecovery);
IdentifierInfo *NewII = Correction.getCorrectionAsIdentifierInfo();
TemplateTy Template;
bool MemberOfUnknownSpecialization;
UnqualifiedId TemplateName;
TemplateName.setIdentifier(NewII, NameLoc);
NestedNameSpecifier *NNS = Correction.getCorrectionSpecifier();
CXXScopeSpec NewSS, *NewSSPtr = SS;
if (SS && NNS) {
NewSS.MakeTrivial(Context, NNS, SourceRange(NameLoc));
NewSSPtr = &NewSS;
}
if (Correction && (NNS || NewII != &II) &&
// Ignore a correction to a template type as the to-be-corrected
// identifier is not a template (typo correction for template names
// is handled elsewhere).
!(getLangOpts().CPlusPlus && NewSSPtr &&
isTemplateName(S, *NewSSPtr, false, TemplateName, nullptr, false,
Template, MemberOfUnknownSpecialization))) {
ParsedType Ty = getTypeName(*NewII, NameLoc, S, NewSSPtr,
isClassName, HasTrailingDot, ObjectTypePtr,
IsCtorOrDtorName,
WantNontrivialTypeSourceInfo,
IsClassTemplateDeductionContext);
if (Ty) {
diagnoseTypo(Correction,
PDiag(diag::err_unknown_type_or_class_name_suggest)
<< Result.getLookupName() << isClassName);
if (SS && NNS)
SS->MakeTrivial(Context, NNS, SourceRange(NameLoc));
*CorrectedII = NewII;
return Ty;
}
}
}
// If typo correction failed or was not performed, fall through
LLVM_FALLTHROUGH;
case LookupResult::FoundOverloaded:
case LookupResult::FoundUnresolvedValue:
Result.suppressDiagnostics();
return nullptr;
case LookupResult::Ambiguous:
// Recover from type-hiding ambiguities by hiding the type. We'll
// do the lookup again when looking for an object, and we can
// diagnose the error then. If we don't do this, then the error
// about hiding the type will be immediately followed by an error
// that only makes sense if the identifier was treated like a type.
if (Result.getAmbiguityKind() == LookupResult::AmbiguousTagHiding) {
Result.suppressDiagnostics();
return nullptr;
}
// Look to see if we have a type anywhere in the list of results.
for (LookupResult::iterator Res = Result.begin(), ResEnd = Result.end();
Res != ResEnd; ++Res) {
NamedDecl *RealRes = (*Res)->getUnderlyingDecl();
if (isa<TypeDecl, ObjCInterfaceDecl, UnresolvedUsingIfExistsDecl>(
RealRes) ||
(AllowDeducedTemplate && getAsTypeTemplateDecl(RealRes))) {
if (!IIDecl ||
// Make the selection of the recovery decl deterministic.
RealRes->getLocation() < IIDecl->getLocation())
IIDecl = RealRes;
}
}
if (!IIDecl) {
// None of the entities we found is a type, so there is no way
// to even assume that the result is a type. In this case, don't
// complain about the ambiguity. The parser will either try to
// perform this lookup again (e.g., as an object name), which
// will produce the ambiguity, or will complain that it expected
// a type name.
Result.suppressDiagnostics();
return nullptr;
}
// We found a type within the ambiguous lookup; diagnose the
// ambiguity and then return that type. This might be the right
// answer, or it might not be, but it suppresses any attempt to
// perform the name lookup again.
break;
case LookupResult::Found:
IIDecl = Result.getFoundDecl();
break;
}
assert(IIDecl && "Didn't find decl");
QualType T;
if (TypeDecl *TD = dyn_cast<TypeDecl>(IIDecl)) {
// C++ [class.qual]p2: A lookup that would find the injected-class-name
// instead names the constructors of the class, except when naming a class.
// This is ill-formed when we're not actually forming a ctor or dtor name.
auto *LookupRD = dyn_cast_or_null<CXXRecordDecl>(LookupCtx);
auto *FoundRD = dyn_cast<CXXRecordDecl>(TD);
if (!isClassName && !IsCtorOrDtorName && LookupRD && FoundRD &&
FoundRD->isInjectedClassName() &&
declaresSameEntity(LookupRD, cast<Decl>(FoundRD->getParent())))
Diag(NameLoc, diag::err_out_of_line_qualified_id_type_names_constructor)
<< &II << /*Type*/1;
DiagnoseUseOfDecl(IIDecl, NameLoc);
T = Context.getTypeDeclType(TD);
MarkAnyDeclReferenced(TD->getLocation(), TD, /*OdrUse=*/false);
} else if (ObjCInterfaceDecl *IDecl = dyn_cast<ObjCInterfaceDecl>(IIDecl)) {
(void)DiagnoseUseOfDecl(IDecl, NameLoc);
if (!HasTrailingDot)
T = Context.getObjCInterfaceType(IDecl);
} else if (auto *UD = dyn_cast<UnresolvedUsingIfExistsDecl>(IIDecl)) {
(void)DiagnoseUseOfDecl(UD, NameLoc);
// Recover with 'int'
T = Context.IntTy;
} else if (AllowDeducedTemplate) {
if (auto *TD = getAsTypeTemplateDecl(IIDecl))
T = Context.getDeducedTemplateSpecializationType(TemplateName(TD),
QualType(), false);
}
if (T.isNull()) {
// If it's not plausibly a type, suppress diagnostics.
Result.suppressDiagnostics();
return nullptr;
}
// NOTE: avoid constructing an ElaboratedType(Loc) if this is a
// constructor or destructor name (in such a case, the scope specifier
// will be attached to the enclosing Expr or Decl node).
if (SS && SS->isNotEmpty() && !IsCtorOrDtorName &&
!isa<ObjCInterfaceDecl, UnresolvedUsingIfExistsDecl>(IIDecl)) {
if (WantNontrivialTypeSourceInfo) {
// Construct a type with type-source information.
TypeLocBuilder Builder;
Builder.pushTypeSpec(T).setNameLoc(NameLoc);
T = getElaboratedType(ETK_None, *SS, T);
ElaboratedTypeLoc ElabTL = Builder.push<ElaboratedTypeLoc>(T);
ElabTL.setElaboratedKeywordLoc(SourceLocation());
ElabTL.setQualifierLoc(SS->getWithLocInContext(Context));
return CreateParsedType(T, Builder.getTypeSourceInfo(Context, T));
} else {
T = getElaboratedType(ETK_None, *SS, T);
}
}
return ParsedType::make(T);
}
// Builds a fake NNS for the given decl context.
static NestedNameSpecifier *
synthesizeCurrentNestedNameSpecifier(ASTContext &Context, DeclContext *DC) {
for (;; DC = DC->getLookupParent()) {
DC = DC->getPrimaryContext();
auto *ND = dyn_cast<NamespaceDecl>(DC);
if (ND && !ND->isInline() && !ND->isAnonymousNamespace())
return NestedNameSpecifier::Create(Context, nullptr, ND);
else if (auto *RD = dyn_cast<CXXRecordDecl>(DC))
return NestedNameSpecifier::Create(Context, nullptr, RD->isTemplateDecl(),
RD->getTypeForDecl());
else if (isa<TranslationUnitDecl>(DC))
return NestedNameSpecifier::GlobalSpecifier(Context);
}
llvm_unreachable("something isn't in TU scope?");
}
/// Find the parent class with dependent bases of the innermost enclosing method
/// context. Do not look for enclosing CXXRecordDecls directly, or we will end
/// up allowing unqualified dependent type names at class-level, which MSVC
/// correctly rejects.
static const CXXRecordDecl *
findRecordWithDependentBasesOfEnclosingMethod(const DeclContext *DC) {
for (; DC && DC->isDependentContext(); DC = DC->getLookupParent()) {
DC = DC->getPrimaryContext();
if (const auto *MD = dyn_cast<CXXMethodDecl>(DC))
if (MD->getParent()->hasAnyDependentBases())
return MD->getParent();
}
return nullptr;
}
ParsedType Sema::ActOnMSVCUnknownTypeName(const IdentifierInfo &II,
SourceLocation NameLoc,
bool IsTemplateTypeArg) {
assert(getLangOpts().MSVCCompat && "shouldn't be called in non-MSVC mode");
NestedNameSpecifier *NNS = nullptr;
if (IsTemplateTypeArg && getCurScope()->isTemplateParamScope()) {
// If we weren't able to parse a default template argument, delay lookup
// until instantiation time by making a non-dependent DependentTypeName. We
// pretend we saw a NestedNameSpecifier referring to the current scope, and
// lookup is retried.
// FIXME: This hurts our diagnostic quality, since we get errors like "no
// type named 'Foo' in 'current_namespace'" when the user didn't write any
// name specifiers.
NNS = synthesizeCurrentNestedNameSpecifier(Context, CurContext);
Diag(NameLoc, diag::ext_ms_delayed_template_argument) << &II;
} else if (const CXXRecordDecl *RD =
findRecordWithDependentBasesOfEnclosingMethod(CurContext)) {
// Build a DependentNameType that will perform lookup into RD at
// instantiation time.
NNS = NestedNameSpecifier::Create(Context, nullptr, RD->isTemplateDecl(),
RD->getTypeForDecl());
// Diagnose that this identifier was undeclared, and retry the lookup during
// template instantiation.
Diag(NameLoc, diag::ext_undeclared_unqual_id_with_dependent_base) << &II
<< RD;
} else {
// This is not a situation that we should recover from.
return ParsedType();
}
QualType T = Context.getDependentNameType(ETK_None, NNS, &II);
// Build type location information. We synthesized the qualifier, so we have
// to build a fake NestedNameSpecifierLoc.
NestedNameSpecifierLocBuilder NNSLocBuilder;
NNSLocBuilder.MakeTrivial(Context, NNS, SourceRange(NameLoc));
NestedNameSpecifierLoc QualifierLoc = NNSLocBuilder.getWithLocInContext(Context);
TypeLocBuilder Builder;
DependentNameTypeLoc DepTL = Builder.push<DependentNameTypeLoc>(T);
DepTL.setNameLoc(NameLoc);
DepTL.setElaboratedKeywordLoc(SourceLocation());
DepTL.setQualifierLoc(QualifierLoc);
return CreateParsedType(T, Builder.getTypeSourceInfo(Context, T));
}
/// isTagName() - This method is called *for error recovery purposes only*
/// to determine if the specified name is a valid tag name ("struct foo"). If
/// so, this returns the TST for the tag corresponding to it (TST_enum,
/// TST_union, TST_struct, TST_interface, TST_class). This is used to diagnose
/// cases in C where the user forgot to specify the tag.
DeclSpec::TST Sema::isTagName(IdentifierInfo &II, Scope *S) {
// Do a tag name lookup in this scope.
LookupResult R(*this, &II, SourceLocation(), LookupTagName);
LookupName(R, S, false);
R.suppressDiagnostics();
if (R.getResultKind() == LookupResult::Found)
if (const TagDecl *TD = R.getAsSingle<TagDecl>()) {
switch (TD->getTagKind()) {
case TTK_Struct: return DeclSpec::TST_struct;
case TTK_Interface: return DeclSpec::TST_interface;
case TTK_Union: return DeclSpec::TST_union;
case TTK_Class: return DeclSpec::TST_class;
case TTK_Enum: return DeclSpec::TST_enum;
}
}
return DeclSpec::TST_unspecified;
}
/// isMicrosoftMissingTypename - In Microsoft mode, within class scope,
/// if a CXXScopeSpec's type is equal to the type of one of the base classes
/// then downgrade the missing typename error to a warning.
/// This is needed for MSVC compatibility; Example:
/// @code
/// template<class T> class A {
/// public:
/// typedef int TYPE;
/// };
/// template<class T> class B : public A<T> {
/// public:
/// A<T>::TYPE a; // no typename required because A<T> is a base class.
/// };
/// @endcode
bool Sema::isMicrosoftMissingTypename(const CXXScopeSpec *SS, Scope *S) {
if (CurContext->isRecord()) {
if (SS->getScopeRep()->getKind() == NestedNameSpecifier::Super)
return true;
const Type *Ty = SS->getScopeRep()->getAsType();
CXXRecordDecl *RD = cast<CXXRecordDecl>(CurContext);
for (const auto &Base : RD->bases())
if (Ty && Context.hasSameUnqualifiedType(QualType(Ty, 1), Base.getType()))
return true;
return S->isFunctionPrototypeScope();
}
return CurContext->isFunctionOrMethod() || S->isFunctionPrototypeScope();
}
void Sema::DiagnoseUnknownTypeName(IdentifierInfo *&II,
SourceLocation IILoc,
Scope *S,
CXXScopeSpec *SS,
ParsedType &SuggestedType,
bool IsTemplateName) {
// Don't report typename errors for editor placeholders.
if (II->isEditorPlaceholder())
return;
// We don't have anything to suggest (yet).
SuggestedType = nullptr;
// There may have been a typo in the name of the type. Look up typo
// results, in case we have something that we can suggest.
TypeNameValidatorCCC CCC(/*AllowInvalid=*/false, /*WantClass=*/false,
/*AllowTemplates=*/IsTemplateName,
/*AllowNonTemplates=*/!IsTemplateName);
if (TypoCorrection Corrected =
CorrectTypo(DeclarationNameInfo(II, IILoc), LookupOrdinaryName, S, SS,
CCC, CTK_ErrorRecovery)) {
// FIXME: Support error recovery for the template-name case.
bool CanRecover = !IsTemplateName;
if (Corrected.isKeyword()) {
// We corrected to a keyword.
diagnoseTypo(Corrected,
PDiag(IsTemplateName ? diag::err_no_template_suggest
: diag::err_unknown_typename_suggest)
<< II);
II = Corrected.getCorrectionAsIdentifierInfo();
} else {
// We found a similarly-named type or interface; suggest that.
if (!SS || !SS->isSet()) {
diagnoseTypo(Corrected,
PDiag(IsTemplateName ? diag::err_no_template_suggest
: diag::err_unknown_typename_suggest)
<< II, CanRecover);
} else if (DeclContext *DC = computeDeclContext(*SS, false)) {
std::string CorrectedStr(Corrected.getAsString(getLangOpts()));
bool DroppedSpecifier = Corrected.WillReplaceSpecifier() &&
II->getName().equals(CorrectedStr);
diagnoseTypo(Corrected,
PDiag(IsTemplateName
? diag::err_no_member_template_suggest
: diag::err_unknown_nested_typename_suggest)
<< II << DC << DroppedSpecifier << SS->getRange(),
CanRecover);
} else {
llvm_unreachable("could not have corrected a typo here");
}
if (!CanRecover)
return;
CXXScopeSpec tmpSS;
if (Corrected.getCorrectionSpecifier())
tmpSS.MakeTrivial(Context, Corrected.getCorrectionSpecifier(),
SourceRange(IILoc));
// FIXME: Support class template argument deduction here.
SuggestedType =
getTypeName(*Corrected.getCorrectionAsIdentifierInfo(), IILoc, S,
tmpSS.isSet() ? &tmpSS : SS, false, false, nullptr,
/*IsCtorOrDtorName=*/false,
/*WantNontrivialTypeSourceInfo=*/true);
}
return;
}
if (getLangOpts().CPlusPlus && !IsTemplateName) {
// See if II is a class template that the user forgot to pass arguments to.
UnqualifiedId Name;
Name.setIdentifier(II, IILoc);
CXXScopeSpec EmptySS;
TemplateTy TemplateResult;
bool MemberOfUnknownSpecialization;
if (isTemplateName(S, SS ? *SS : EmptySS, /*hasTemplateKeyword=*/false,
Name, nullptr, true, TemplateResult,
MemberOfUnknownSpecialization) == TNK_Type_template) {
diagnoseMissingTemplateArguments(TemplateResult.get(), IILoc);
return;
}
}
// FIXME: Should we move the logic that tries to recover from a missing tag
// (struct, union, enum) from Parser::ParseImplicitInt here, instead?
if (!SS || (!SS->isSet() && !SS->isInvalid()))
Diag(IILoc, IsTemplateName ? diag::err_no_template
: diag::err_unknown_typename)
<< II;
else if (DeclContext *DC = computeDeclContext(*SS, false))
Diag(IILoc, IsTemplateName ? diag::err_no_member_template
: diag::err_typename_nested_not_found)
<< II << DC << SS->getRange();
else if (SS->isValid() && SS->getScopeRep()->containsErrors()) {
SuggestedType =
ActOnTypenameType(S, SourceLocation(), *SS, *II, IILoc).get();
} else if (isDependentScopeSpecifier(*SS)) {
unsigned DiagID = diag::err_typename_missing;
if (getLangOpts().MSVCCompat && isMicrosoftMissingTypename(SS, S))
DiagID = diag::ext_typename_missing;
Diag(SS->getRange().getBegin(), DiagID)
<< SS->getScopeRep() << II->getName()
<< SourceRange(SS->getRange().getBegin(), IILoc)
<< FixItHint::CreateInsertion(SS->getRange().getBegin(), "typename ");
SuggestedType = ActOnTypenameType(S, SourceLocation(),
*SS, *II, IILoc).get();
} else {
assert(SS && SS->isInvalid() &&
"Invalid scope specifier has already been diagnosed");
}
}
/// Determine whether the given result set contains either a type name
/// or
static bool isResultTypeOrTemplate(LookupResult &R, const Token &NextToken) {
bool CheckTemplate = R.getSema().getLangOpts().CPlusPlus &&
NextToken.is(tok::less);
for (LookupResult::iterator I = R.begin(), IEnd = R.end(); I != IEnd; ++I) {
if (isa<TypeDecl>(*I) || isa<ObjCInterfaceDecl>(*I))
return true;
if (CheckTemplate && isa<TemplateDecl>(*I))
return true;
}
return false;
}
static bool isTagTypeWithMissingTag(Sema &SemaRef, LookupResult &Result,
Scope *S, CXXScopeSpec &SS,
IdentifierInfo *&Name,
SourceLocation NameLoc) {
LookupResult R(SemaRef, Name, NameLoc, Sema::LookupTagName);
SemaRef.LookupParsedName(R, S, &SS);
if (TagDecl *Tag = R.getAsSingle<TagDecl>()) {
StringRef FixItTagName;
switch (Tag->getTagKind()) {
case TTK_Class:
FixItTagName = "class ";
break;
case TTK_Enum:
FixItTagName = "enum ";
break;
case TTK_Struct:
FixItTagName = "struct ";
break;
case TTK_Interface:
FixItTagName = "__interface ";
break;
case TTK_Union:
FixItTagName = "union ";
break;
}
StringRef TagName = FixItTagName.drop_back();
SemaRef.Diag(NameLoc, diag::err_use_of_tag_name_without_tag)
<< Name << TagName << SemaRef.getLangOpts().CPlusPlus
<< FixItHint::CreateInsertion(NameLoc, FixItTagName);
for (LookupResult::iterator I = Result.begin(), IEnd = Result.end();
I != IEnd; ++I)
SemaRef.Diag((*I)->getLocation(), diag::note_decl_hiding_tag_type)
<< Name << TagName;
// Replace lookup results with just the tag decl.
Result.clear(Sema::LookupTagName);
SemaRef.LookupParsedName(Result, S, &SS);
return true;
}
return false;
}
/// Build a ParsedType for a simple-type-specifier with a nested-name-specifier.
static ParsedType buildNestedType(Sema &S, CXXScopeSpec &SS,
QualType T, SourceLocation NameLoc) {
ASTContext &Context = S.Context;
TypeLocBuilder Builder;
Builder.pushTypeSpec(T).setNameLoc(NameLoc);
T = S.getElaboratedType(ETK_None, SS, T);
ElaboratedTypeLoc ElabTL = Builder.push<ElaboratedTypeLoc>(T);
ElabTL.setElaboratedKeywordLoc(SourceLocation());
ElabTL.setQualifierLoc(SS.getWithLocInContext(Context));
return S.CreateParsedType(T, Builder.getTypeSourceInfo(Context, T));
}
Sema::NameClassification Sema::ClassifyName(Scope *S, CXXScopeSpec &SS,
IdentifierInfo *&Name,
SourceLocation NameLoc,
const Token &NextToken,
CorrectionCandidateCallback *CCC) {
DeclarationNameInfo NameInfo(Name, NameLoc);
ObjCMethodDecl *CurMethod = getCurMethodDecl();
assert(NextToken.isNot(tok::coloncolon) &&
"parse nested name specifiers before calling ClassifyName");
if (getLangOpts().CPlusPlus && SS.isSet() &&
isCurrentClassName(*Name, S, &SS)) {
// Per [class.qual]p2, this names the constructors of SS, not the
// injected-class-name. We don't have a classification for that.
// There's not much point caching this result, since the parser
// will reject it later.
return NameClassification::Unknown();
}
LookupResult Result(*this, Name, NameLoc, LookupOrdinaryName);
LookupParsedName(Result, S, &SS, !CurMethod);
if (SS.isInvalid())
return NameClassification::Error();
// For unqualified lookup in a class template in MSVC mode, look into
// dependent base classes where the primary class template is known.
if (Result.empty() && SS.isEmpty() && getLangOpts().MSVCCompat) {
if (ParsedType TypeInBase =
recoverFromTypeInKnownDependentBase(*this, *Name, NameLoc))
return TypeInBase;
}
// Perform lookup for Objective-C instance variables (including automatically
// synthesized instance variables), if we're in an Objective-C method.
// FIXME: This lookup really, really needs to be folded in to the normal
// unqualified lookup mechanism.
if (SS.isEmpty() && CurMethod && !isResultTypeOrTemplate(Result, NextToken)) {
DeclResult Ivar = LookupIvarInObjCMethod(Result, S, Name);
if (Ivar.isInvalid())
return NameClassification::Error();
if (Ivar.isUsable())
return NameClassification::NonType(cast<NamedDecl>(Ivar.get()));
// We defer builtin creation until after ivar lookup inside ObjC methods.
if (Result.empty())
LookupBuiltin(Result);
}
bool SecondTry = false;
bool IsFilteredTemplateName = false;
Corrected:
switch (Result.getResultKind()) {
case LookupResult::NotFound:
// If an unqualified-id is followed by a '(', then we have a function
// call.
if (SS.isEmpty() && NextToken.is(tok::l_paren)) {
// In C++, this is an ADL-only call.
// FIXME: Reference?
if (getLangOpts().CPlusPlus)
return NameClassification::UndeclaredNonType();
// C90 6.3.2.2:
// If the expression that precedes the parenthesized argument list in a
// function call consists solely of an identifier, and if no
// declaration is visible for this identifier, the identifier is
// implicitly declared exactly as if, in the innermost block containing
// the function call, the declaration
//
// extern int identifier ();
//
// appeared.
//
// We also allow this in C99 as an extension.
if (NamedDecl *D = ImplicitlyDefineFunction(NameLoc, *Name, S))
return NameClassification::NonType(D);
}
if (getLangOpts().CPlusPlus20 && SS.isEmpty() && NextToken.is(tok::less)) {
// In C++20 onwards, this could be an ADL-only call to a function
// template, and we're required to assume that this is a template name.
//
// FIXME: Find a way to still do typo correction in this case.
TemplateName Template =
Context.getAssumedTemplateName(NameInfo.getName());
return NameClassification::UndeclaredTemplate(Template);
}
// In C, we first see whether there is a tag type by the same name, in
// which case it's likely that the user just forgot to write "enum",
// "struct", or "union".
if (!getLangOpts().CPlusPlus && !SecondTry &&
isTagTypeWithMissingTag(*this, Result, S, SS, Name, NameLoc)) {
break;
}
// Perform typo correction to determine if there is another name that is
// close to this name.
if (!SecondTry && CCC) {
SecondTry = true;
if (TypoCorrection Corrected =
CorrectTypo(Result.getLookupNameInfo(), Result.getLookupKind(), S,
&SS, *CCC, CTK_ErrorRecovery)) {
unsigned UnqualifiedDiag = diag::err_undeclared_var_use_suggest;
unsigned QualifiedDiag = diag::err_no_member_suggest;
NamedDecl *FirstDecl = Corrected.getFoundDecl();
NamedDecl *UnderlyingFirstDecl = Corrected.getCorrectionDecl();
if (getLangOpts().CPlusPlus && NextToken.is(tok::less) &&
UnderlyingFirstDecl && isa<TemplateDecl>(UnderlyingFirstDecl)) {
UnqualifiedDiag = diag::err_no_template_suggest;
QualifiedDiag = diag::err_no_member_template_suggest;
} else if (UnderlyingFirstDecl &&
(isa<TypeDecl>(UnderlyingFirstDecl) ||
isa<ObjCInterfaceDecl>(UnderlyingFirstDecl) ||
isa<ObjCCompatibleAliasDecl>(UnderlyingFirstDecl))) {
UnqualifiedDiag = diag::err_unknown_typename_suggest;
QualifiedDiag = diag::err_unknown_nested_typename_suggest;
}
if (SS.isEmpty()) {
diagnoseTypo(Corrected, PDiag(UnqualifiedDiag) << Name);
} else {// FIXME: is this even reachable? Test it.
std::string CorrectedStr(Corrected.getAsString(getLangOpts()));
bool DroppedSpecifier = Corrected.WillReplaceSpecifier() &&
Name->getName().equals(CorrectedStr);
diagnoseTypo(Corrected, PDiag(QualifiedDiag)
<< Name << computeDeclContext(SS, false)
<< DroppedSpecifier << SS.getRange());
}
// Update the name, so that the caller has the new name.
Name = Corrected.getCorrectionAsIdentifierInfo();
// Typo correction corrected to a keyword.
if (Corrected.isKeyword())
return Name;
// Also update the LookupResult...
// FIXME: This should probably go away at some point