Reapply "[Clang] Implement resolution for CWG1835 (#92957)" #98547
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@llvm/pr-subscribers-llvm-adt @llvm/pr-subscribers-libcxx Author: Krystian Stasiowski (sdkrystian) ChangesReapplies #92957, fixing an instance where the Patch is 156.84 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/98547.diff 47 Files Affected:
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index d5446f7fd92cc..be2f06766a755 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -310,6 +310,9 @@ Resolutions to C++ Defect Reports
- Clang now considers ``noexcept(typeid(expr))`` more carefully, instead of always assuming that ``std::bad_typeid`` can be thrown.
(`CWG2191: Incorrect result for noexcept(typeid(v)) <https://cplusplus.github.io/CWG/issues/2191.html>`_).
+- Clang now correctly implements lookup for the terminal name of a member-qualified nested-name-specifier.
+ (`CWG1835: Dependent member lookup before < <https://cplusplus.github.io/CWG/issues/1835.html>`_).
+
C Language Changes
------------------
diff --git a/clang/include/clang/AST/ExprCXX.h b/clang/include/clang/AST/ExprCXX.h
index c2feac525c1ea..edaea6fe27cc3 100644
--- a/clang/include/clang/AST/ExprCXX.h
+++ b/clang/include/clang/AST/ExprCXX.h
@@ -3676,9 +3676,9 @@ class CXXUnresolvedConstructExpr final
/// an implicit access if a qualifier is provided.
class CXXDependentScopeMemberExpr final
: public Expr,
- private llvm::TrailingObjects<CXXDependentScopeMemberExpr,
- ASTTemplateKWAndArgsInfo,
- TemplateArgumentLoc, NamedDecl *> {
+ private llvm::TrailingObjects<
+ CXXDependentScopeMemberExpr, NestedNameSpecifierLoc, DeclAccessPair,
+ ASTTemplateKWAndArgsInfo, TemplateArgumentLoc> {
friend class ASTStmtReader;
friend class ASTStmtWriter;
friend TrailingObjects;
@@ -3691,17 +3691,15 @@ class CXXDependentScopeMemberExpr final
/// implicit accesses.
QualType BaseType;
- /// The nested-name-specifier that precedes the member name, if any.
- /// FIXME: This could be in principle store as a trailing object.
- /// However the performance impact of doing so should be investigated first.
- NestedNameSpecifierLoc QualifierLoc;
-
/// The member to which this member expression refers, which
/// can be name, overloaded operator, or destructor.
///
/// FIXME: could also be a template-id
DeclarationNameInfo MemberNameInfo;
+ /// The location of the '->' or '.' operator.
+ SourceLocation OperatorLoc;
+
// CXXDependentScopeMemberExpr is followed by several trailing objects,
// some of which optional. They are in order:
//
@@ -3721,8 +3719,16 @@ class CXXDependentScopeMemberExpr final
return CXXDependentScopeMemberExprBits.HasTemplateKWAndArgsInfo;
}
- bool hasFirstQualifierFoundInScope() const {
- return CXXDependentScopeMemberExprBits.HasFirstQualifierFoundInScope;
+ unsigned getNumUnqualifiedLookups() const {
+ return CXXDependentScopeMemberExprBits.NumUnqualifiedLookups;
+ }
+
+ unsigned numTrailingObjects(OverloadToken<NestedNameSpecifierLoc>) const {
+ return hasQualifier();
+ }
+
+ unsigned numTrailingObjects(OverloadToken<DeclAccessPair>) const {
+ return getNumUnqualifiedLookups();
}
unsigned numTrailingObjects(OverloadToken<ASTTemplateKWAndArgsInfo>) const {
@@ -3733,33 +3739,32 @@ class CXXDependentScopeMemberExpr final
return getNumTemplateArgs();
}
- unsigned numTrailingObjects(OverloadToken<NamedDecl *>) const {
- return hasFirstQualifierFoundInScope();
- }
-
CXXDependentScopeMemberExpr(const ASTContext &Ctx, Expr *Base,
QualType BaseType, bool IsArrow,
SourceLocation OperatorLoc,
NestedNameSpecifierLoc QualifierLoc,
SourceLocation TemplateKWLoc,
- NamedDecl *FirstQualifierFoundInScope,
+ ArrayRef<DeclAccessPair> UnqualifiedLookups,
DeclarationNameInfo MemberNameInfo,
const TemplateArgumentListInfo *TemplateArgs);
- CXXDependentScopeMemberExpr(EmptyShell Empty, bool HasTemplateKWAndArgsInfo,
- bool HasFirstQualifierFoundInScope);
+ CXXDependentScopeMemberExpr(EmptyShell Empty, bool HasQualifier,
+ unsigned NumUnqualifiedLookups,
+ bool HasTemplateKWAndArgsInfo);
public:
static CXXDependentScopeMemberExpr *
Create(const ASTContext &Ctx, Expr *Base, QualType BaseType, bool IsArrow,
SourceLocation OperatorLoc, NestedNameSpecifierLoc QualifierLoc,
- SourceLocation TemplateKWLoc, NamedDecl *FirstQualifierFoundInScope,
+ SourceLocation TemplateKWLoc,
+ ArrayRef<DeclAccessPair> UnqualifiedLookups,
DeclarationNameInfo MemberNameInfo,
const TemplateArgumentListInfo *TemplateArgs);
static CXXDependentScopeMemberExpr *
- CreateEmpty(const ASTContext &Ctx, bool HasTemplateKWAndArgsInfo,
- unsigned NumTemplateArgs, bool HasFirstQualifierFoundInScope);
+ CreateEmpty(const ASTContext &Ctx, bool HasQualifier,
+ unsigned NumUnqualifiedLookups, bool HasTemplateKWAndArgsInfo,
+ unsigned NumTemplateArgs);
/// True if this is an implicit access, i.e. one in which the
/// member being accessed was not written in the source. The source
@@ -3784,34 +3789,35 @@ class CXXDependentScopeMemberExpr final
bool isArrow() const { return CXXDependentScopeMemberExprBits.IsArrow; }
/// Retrieve the location of the '->' or '.' operator.
- SourceLocation getOperatorLoc() const {
- return CXXDependentScopeMemberExprBits.OperatorLoc;
+ SourceLocation getOperatorLoc() const { return OperatorLoc; }
+
+ /// Determines whether this member expression had a nested-name-specifier
+ /// prior to the name of the member, e.g., x->Base::foo.
+ bool hasQualifier() const {
+ return CXXDependentScopeMemberExprBits.HasQualifier;
}
- /// Retrieve the nested-name-specifier that qualifies the member name.
- NestedNameSpecifier *getQualifier() const {
- return QualifierLoc.getNestedNameSpecifier();
+ /// If the member name was qualified, retrieves the nested-name-specifier
+ /// that precedes the member name, with source-location information.
+ NestedNameSpecifierLoc getQualifierLoc() const {
+ if (!hasQualifier())
+ return NestedNameSpecifierLoc();
+ return *getTrailingObjects<NestedNameSpecifierLoc>();
}
- /// Retrieve the nested-name-specifier that qualifies the member
- /// name, with source location information.
- NestedNameSpecifierLoc getQualifierLoc() const { return QualifierLoc; }
+ /// If the member name was qualified, retrieves the
+ /// nested-name-specifier that precedes the member name. Otherwise, returns
+ /// NULL.
+ NestedNameSpecifier *getQualifier() const {
+ return getQualifierLoc().getNestedNameSpecifier();
+ }
- /// Retrieve the first part of the nested-name-specifier that was
- /// found in the scope of the member access expression when the member access
- /// was initially parsed.
- ///
- /// This function only returns a useful result when member access expression
- /// uses a qualified member name, e.g., "x.Base::f". Here, the declaration
- /// returned by this function describes what was found by unqualified name
- /// lookup for the identifier "Base" within the scope of the member access
- /// expression itself. At template instantiation time, this information is
- /// combined with the results of name lookup into the type of the object
- /// expression itself (the class type of x).
- NamedDecl *getFirstQualifierFoundInScope() const {
- if (!hasFirstQualifierFoundInScope())
- return nullptr;
- return *getTrailingObjects<NamedDecl *>();
+ /// Retrieve the declarations found by unqualified lookup for the first
+ /// component name of the nested-name-specifier, if any.
+ ArrayRef<DeclAccessPair> unqualified_lookups() const {
+ if (!getNumUnqualifiedLookups())
+ return std::nullopt;
+ return {getTrailingObjects<DeclAccessPair>(), getNumUnqualifiedLookups()};
}
/// Retrieve the name of the member that this expression refers to.
diff --git a/clang/include/clang/AST/Stmt.h b/clang/include/clang/AST/Stmt.h
index 9cd7a364cd3f1..257a61c97c9c6 100644
--- a/clang/include/clang/AST/Stmt.h
+++ b/clang/include/clang/AST/Stmt.h
@@ -1020,18 +1020,19 @@ class alignas(void *) Stmt {
LLVM_PREFERRED_TYPE(bool)
unsigned IsArrow : 1;
+ /// True if this member expression used a nested-name-specifier to
+ /// refer to the member, e.g., "x->Base::f".
+ LLVM_PREFERRED_TYPE(bool)
+ unsigned HasQualifier : 1;
+
/// Whether this member expression has info for explicit template
/// keyword and arguments.
LLVM_PREFERRED_TYPE(bool)
unsigned HasTemplateKWAndArgsInfo : 1;
- /// See getFirstQualifierFoundInScope() and the comment listing
- /// the trailing objects.
- LLVM_PREFERRED_TYPE(bool)
- unsigned HasFirstQualifierFoundInScope : 1;
-
- /// The location of the '->' or '.' operator.
- SourceLocation OperatorLoc;
+ /// Number of declarations found by unqualified lookup for the
+ /// first component name of the nested-name-specifier.
+ unsigned NumUnqualifiedLookups;
};
class OverloadExprBitfields {
diff --git a/clang/include/clang/AST/UnresolvedSet.h b/clang/include/clang/AST/UnresolvedSet.h
index 1369725ab4e96..ef44499ce5926 100644
--- a/clang/include/clang/AST/UnresolvedSet.h
+++ b/clang/include/clang/AST/UnresolvedSet.h
@@ -97,6 +97,10 @@ class UnresolvedSetImpl {
decls().push_back(DeclAccessPair::make(D, AS));
}
+ void addAllDecls(ArrayRef<DeclAccessPair> Other) {
+ append(iterator(Other.begin()), iterator(Other.end()));
+ }
+
/// Replaces the given declaration with the new one, once.
///
/// \return true if the set changed
diff --git a/clang/include/clang/Basic/DiagnosticParseKinds.td b/clang/include/clang/Basic/DiagnosticParseKinds.td
index 12aab09f28556..0bd2e35bf2e31 100644
--- a/clang/include/clang/Basic/DiagnosticParseKinds.td
+++ b/clang/include/clang/Basic/DiagnosticParseKinds.td
@@ -895,9 +895,7 @@ def missing_template_arg_list_after_template_kw : Extension<
"keyword">, InGroup<DiagGroup<"missing-template-arg-list-after-template-kw">>,
DefaultError;
-def err_missing_dependent_template_keyword : Error<
- "use 'template' keyword to treat '%0' as a dependent template name">;
-def warn_missing_dependent_template_keyword : ExtWarn<
+def ext_missing_dependent_template_keyword : ExtWarn<
"use 'template' keyword to treat '%0' as a dependent template name">;
def ext_extern_template : Extension<
diff --git a/clang/include/clang/Parse/Parser.h b/clang/include/clang/Parse/Parser.h
index 6880fa4bb0b03..b4f5270a35956 100644
--- a/clang/include/clang/Parse/Parser.h
+++ b/clang/include/clang/Parse/Parser.h
@@ -3368,15 +3368,11 @@ class Parser : public CodeCompletionHandler {
BaseResult ParseBaseSpecifier(Decl *ClassDecl);
AccessSpecifier getAccessSpecifierIfPresent() const;
- bool ParseUnqualifiedIdTemplateId(CXXScopeSpec &SS,
- ParsedType ObjectType,
- bool ObjectHadErrors,
- SourceLocation TemplateKWLoc,
- IdentifierInfo *Name,
- SourceLocation NameLoc,
- bool EnteringContext,
- UnqualifiedId &Id,
- bool AssumeTemplateId);
+ bool ParseUnqualifiedIdTemplateId(
+ CXXScopeSpec &SS, ParsedType ObjectType, bool ObjectHadErrors,
+ SourceLocation TemplateKWLoc, SourceLocation TildeLoc,
+ IdentifierInfo *Name, SourceLocation NameLoc, bool EnteringContext,
+ UnqualifiedId &Id, bool AssumeTemplateId);
bool ParseUnqualifiedIdOperator(CXXScopeSpec &SS, bool EnteringContext,
ParsedType ObjectType,
UnqualifiedId &Result);
diff --git a/clang/include/clang/Sema/DeclSpec.h b/clang/include/clang/Sema/DeclSpec.h
index 425b6e2a0b30c..9c22c35535ede 100644
--- a/clang/include/clang/Sema/DeclSpec.h
+++ b/clang/include/clang/Sema/DeclSpec.h
@@ -75,6 +75,7 @@ class CXXScopeSpec {
SourceRange Range;
NestedNameSpecifierLocBuilder Builder;
ArrayRef<TemplateParameterList *> TemplateParamLists;
+ ArrayRef<DeclAccessPair> UnqualifiedLookups;
public:
SourceRange getRange() const { return Range; }
@@ -91,6 +92,13 @@ class CXXScopeSpec {
return TemplateParamLists;
}
+ void setUnqualifiedLookups(ArrayRef<DeclAccessPair> Found) {
+ UnqualifiedLookups = Found;
+ }
+ ArrayRef<DeclAccessPair> getUnqualifiedLookups() const {
+ return UnqualifiedLookups;
+ }
+
/// Retrieve the representation of the nested-name-specifier.
NestedNameSpecifier *getScopeRep() const {
return Builder.getRepresentation();
diff --git a/clang/include/clang/Sema/Lookup.h b/clang/include/clang/Sema/Lookup.h
index b0a08a05ac6a0..6b765ef3c980f 100644
--- a/clang/include/clang/Sema/Lookup.h
+++ b/clang/include/clang/Sema/Lookup.h
@@ -483,11 +483,15 @@ class LookupResult {
ResultKind = Found;
}
+ void addAllDecls(ArrayRef<DeclAccessPair> Other) {
+ Decls.addAllDecls(Other);
+ ResultKind = Found;
+ }
+
/// Add all the declarations from another set of lookup
/// results.
void addAllDecls(const LookupResult &Other) {
- Decls.append(Other.Decls.begin(), Other.Decls.end());
- ResultKind = Found;
+ addAllDecls(Other.Decls.pairs());
}
/// Determine whether no result was found because we could not
diff --git a/clang/include/clang/Sema/Sema.h b/clang/include/clang/Sema/Sema.h
index 57994f4033922..6be6f6725e5b7 100644
--- a/clang/include/clang/Sema/Sema.h
+++ b/clang/include/clang/Sema/Sema.h
@@ -2802,7 +2802,8 @@ class Sema final : public SemaBase {
/// (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 *FindFirstQualifierInScope(Scope *S, NestedNameSpecifier *NNS);
+ bool LookupFirstQualifierInScope(Scope *S, NestedNameSpecifier *NNS,
+ UnresolvedSetImpl &R);
/// Keeps information about an identifier in a nested-name-spec.
///
@@ -2842,9 +2843,6 @@ class Sema final : public SemaBase {
/// \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 '::' -> ':'
@@ -2853,11 +2851,6 @@ class Sema final : public SemaBase {
/// 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
@@ -2866,7 +2859,6 @@ class Sema final : public SemaBase {
/// specifier.
bool BuildCXXNestedNameSpecifier(Scope *S, NestedNameSpecInfo &IdInfo,
bool EnteringContext, CXXScopeSpec &SS,
- NamedDecl *ScopeLookupResult,
bool ErrorRecoveryLookup,
bool *IsCorrectedToColon = nullptr,
bool OnlyNamespace = false);
@@ -8566,11 +8558,12 @@ class Sema final : public SemaBase {
const TemplateArgumentListInfo *TemplateArgs,
bool IsDefiniteInstance, const Scope *S);
- ExprResult ActOnDependentMemberExpr(
- Expr *Base, QualType BaseType, bool IsArrow, SourceLocation OpLoc,
- const CXXScopeSpec &SS, SourceLocation TemplateKWLoc,
- NamedDecl *FirstQualifierInScope, const DeclarationNameInfo &NameInfo,
- const TemplateArgumentListInfo *TemplateArgs);
+ ExprResult
+ ActOnDependentMemberExpr(Expr *Base, QualType BaseType, bool IsArrow,
+ SourceLocation OpLoc, const CXXScopeSpec &SS,
+ SourceLocation TemplateKWLoc,
+ const DeclarationNameInfo &NameInfo,
+ const TemplateArgumentListInfo *TemplateArgs);
/// The main callback when the parser finds something like
/// expression . [nested-name-specifier] identifier
@@ -8626,15 +8619,14 @@ class Sema final : public SemaBase {
ExprResult BuildMemberReferenceExpr(
Expr *Base, QualType BaseType, SourceLocation OpLoc, bool IsArrow,
CXXScopeSpec &SS, SourceLocation TemplateKWLoc,
- NamedDecl *FirstQualifierInScope, const DeclarationNameInfo &NameInfo,
+ const DeclarationNameInfo &NameInfo,
const TemplateArgumentListInfo *TemplateArgs, const Scope *S,
ActOnMemberAccessExtraArgs *ExtraArgs = nullptr);
ExprResult
BuildMemberReferenceExpr(Expr *Base, QualType BaseType, SourceLocation OpLoc,
bool IsArrow, const CXXScopeSpec &SS,
- SourceLocation TemplateKWLoc,
- NamedDecl *FirstQualifierInScope, LookupResult &R,
+ SourceLocation TemplateKWLoc, LookupResult &R,
const TemplateArgumentListInfo *TemplateArgs,
const Scope *S, bool SuppressQualifierCheck = false,
ActOnMemberAccessExtraArgs *ExtraArgs = nullptr);
@@ -11122,15 +11114,14 @@ class Sema final : public SemaBase {
QualType ObjectType, bool EnteringContext,
RequiredTemplateKind RequiredTemplate = SourceLocation(),
AssumedTemplateKind *ATK = nullptr,
- bool AllowTypoCorrection = true);
+ bool AllowTypoCorrection = true, bool MayBeNNS = false);
- TemplateNameKind isTemplateName(Scope *S, CXXScopeSpec &SS,
- bool hasTemplateKeyword,
- const UnqualifiedId &Name,
- ParsedType ObjectType, bool EnteringContext,
- TemplateTy &Template,
- bool &MemberOfUnknownSpecialization,
- bool Disambiguation = false);
+ TemplateNameKind
+ isTemplateName(Scope *S, CXXScopeSpec &SS, bool hasTemplateKeyword,
+ const UnqualifiedId &Name, ParsedType ObjectType,
+ bool EnteringContext, TemplateTy &Template,
+ bool &MemberOfUnknownSpecialization,
+ bool Disambiguation = false, bool MayBeNNS = false);
/// Try to resolve an undeclared template name as a type template.
///
@@ -11459,12 +11450,11 @@ class Sema final : public SemaBase {
/// For example, given "x.MetaFun::template apply", the scope specifier
/// \p SS will be "MetaFun::", \p TemplateKWLoc contains the location
/// of the "template" keyword, and "apply" is the \p Name.
- TemplateNameKind ActOnTemplateName(Scope *S, CXXScopeSpec &SS,
- SourceLocation TemplateKWLoc,
- const UnqualifiedId &Name,
- ParsedType ObjectType,
- bool EnteringContext, TemplateTy &Template,
- bool AllowInjectedClassName = false);
+ TemplateNameKind
+ ActOnTemplateName(Scope *S, CXXScopeSpec &SS, SourceLocation TemplateKWLoc,
+ const UnqualifiedId &Name, ParsedType ObjectType,
+ bool EnteringContext, TemplateTy &Temp...
[truncated]
|
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@llvm/pr-subscribers-clang-modules Author: Krystian Stasiowski (sdkrystian) ChangesReapplies #92957, fixing an instance where the Patch is 156.84 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/98547.diff 47 Files Affected:
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index d5446f7fd92cc..be2f06766a755 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -310,6 +310,9 @@ Resolutions to C++ Defect Reports
- Clang now considers ``noexcept(typeid(expr))`` more carefully, instead of always assuming that ``std::bad_typeid`` can be thrown.
(`CWG2191: Incorrect result for noexcept(typeid(v)) <https://cplusplus.github.io/CWG/issues/2191.html>`_).
+- Clang now correctly implements lookup for the terminal name of a member-qualified nested-name-specifier.
+ (`CWG1835: Dependent member lookup before < <https://cplusplus.github.io/CWG/issues/1835.html>`_).
+
C Language Changes
------------------
diff --git a/clang/include/clang/AST/ExprCXX.h b/clang/include/clang/AST/ExprCXX.h
index c2feac525c1ea..edaea6fe27cc3 100644
--- a/clang/include/clang/AST/ExprCXX.h
+++ b/clang/include/clang/AST/ExprCXX.h
@@ -3676,9 +3676,9 @@ class CXXUnresolvedConstructExpr final
/// an implicit access if a qualifier is provided.
class CXXDependentScopeMemberExpr final
: public Expr,
- private llvm::TrailingObjects<CXXDependentScopeMemberExpr,
- ASTTemplateKWAndArgsInfo,
- TemplateArgumentLoc, NamedDecl *> {
+ private llvm::TrailingObjects<
+ CXXDependentScopeMemberExpr, NestedNameSpecifierLoc, DeclAccessPair,
+ ASTTemplateKWAndArgsInfo, TemplateArgumentLoc> {
friend class ASTStmtReader;
friend class ASTStmtWriter;
friend TrailingObjects;
@@ -3691,17 +3691,15 @@ class CXXDependentScopeMemberExpr final
/// implicit accesses.
QualType BaseType;
- /// The nested-name-specifier that precedes the member name, if any.
- /// FIXME: This could be in principle store as a trailing object.
- /// However the performance impact of doing so should be investigated first.
- NestedNameSpecifierLoc QualifierLoc;
-
/// The member to which this member expression refers, which
/// can be name, overloaded operator, or destructor.
///
/// FIXME: could also be a template-id
DeclarationNameInfo MemberNameInfo;
+ /// The location of the '->' or '.' operator.
+ SourceLocation OperatorLoc;
+
// CXXDependentScopeMemberExpr is followed by several trailing objects,
// some of which optional. They are in order:
//
@@ -3721,8 +3719,16 @@ class CXXDependentScopeMemberExpr final
return CXXDependentScopeMemberExprBits.HasTemplateKWAndArgsInfo;
}
- bool hasFirstQualifierFoundInScope() const {
- return CXXDependentScopeMemberExprBits.HasFirstQualifierFoundInScope;
+ unsigned getNumUnqualifiedLookups() const {
+ return CXXDependentScopeMemberExprBits.NumUnqualifiedLookups;
+ }
+
+ unsigned numTrailingObjects(OverloadToken<NestedNameSpecifierLoc>) const {
+ return hasQualifier();
+ }
+
+ unsigned numTrailingObjects(OverloadToken<DeclAccessPair>) const {
+ return getNumUnqualifiedLookups();
}
unsigned numTrailingObjects(OverloadToken<ASTTemplateKWAndArgsInfo>) const {
@@ -3733,33 +3739,32 @@ class CXXDependentScopeMemberExpr final
return getNumTemplateArgs();
}
- unsigned numTrailingObjects(OverloadToken<NamedDecl *>) const {
- return hasFirstQualifierFoundInScope();
- }
-
CXXDependentScopeMemberExpr(const ASTContext &Ctx, Expr *Base,
QualType BaseType, bool IsArrow,
SourceLocation OperatorLoc,
NestedNameSpecifierLoc QualifierLoc,
SourceLocation TemplateKWLoc,
- NamedDecl *FirstQualifierFoundInScope,
+ ArrayRef<DeclAccessPair> UnqualifiedLookups,
DeclarationNameInfo MemberNameInfo,
const TemplateArgumentListInfo *TemplateArgs);
- CXXDependentScopeMemberExpr(EmptyShell Empty, bool HasTemplateKWAndArgsInfo,
- bool HasFirstQualifierFoundInScope);
+ CXXDependentScopeMemberExpr(EmptyShell Empty, bool HasQualifier,
+ unsigned NumUnqualifiedLookups,
+ bool HasTemplateKWAndArgsInfo);
public:
static CXXDependentScopeMemberExpr *
Create(const ASTContext &Ctx, Expr *Base, QualType BaseType, bool IsArrow,
SourceLocation OperatorLoc, NestedNameSpecifierLoc QualifierLoc,
- SourceLocation TemplateKWLoc, NamedDecl *FirstQualifierFoundInScope,
+ SourceLocation TemplateKWLoc,
+ ArrayRef<DeclAccessPair> UnqualifiedLookups,
DeclarationNameInfo MemberNameInfo,
const TemplateArgumentListInfo *TemplateArgs);
static CXXDependentScopeMemberExpr *
- CreateEmpty(const ASTContext &Ctx, bool HasTemplateKWAndArgsInfo,
- unsigned NumTemplateArgs, bool HasFirstQualifierFoundInScope);
+ CreateEmpty(const ASTContext &Ctx, bool HasQualifier,
+ unsigned NumUnqualifiedLookups, bool HasTemplateKWAndArgsInfo,
+ unsigned NumTemplateArgs);
/// True if this is an implicit access, i.e. one in which the
/// member being accessed was not written in the source. The source
@@ -3784,34 +3789,35 @@ class CXXDependentScopeMemberExpr final
bool isArrow() const { return CXXDependentScopeMemberExprBits.IsArrow; }
/// Retrieve the location of the '->' or '.' operator.
- SourceLocation getOperatorLoc() const {
- return CXXDependentScopeMemberExprBits.OperatorLoc;
+ SourceLocation getOperatorLoc() const { return OperatorLoc; }
+
+ /// Determines whether this member expression had a nested-name-specifier
+ /// prior to the name of the member, e.g., x->Base::foo.
+ bool hasQualifier() const {
+ return CXXDependentScopeMemberExprBits.HasQualifier;
}
- /// Retrieve the nested-name-specifier that qualifies the member name.
- NestedNameSpecifier *getQualifier() const {
- return QualifierLoc.getNestedNameSpecifier();
+ /// If the member name was qualified, retrieves the nested-name-specifier
+ /// that precedes the member name, with source-location information.
+ NestedNameSpecifierLoc getQualifierLoc() const {
+ if (!hasQualifier())
+ return NestedNameSpecifierLoc();
+ return *getTrailingObjects<NestedNameSpecifierLoc>();
}
- /// Retrieve the nested-name-specifier that qualifies the member
- /// name, with source location information.
- NestedNameSpecifierLoc getQualifierLoc() const { return QualifierLoc; }
+ /// If the member name was qualified, retrieves the
+ /// nested-name-specifier that precedes the member name. Otherwise, returns
+ /// NULL.
+ NestedNameSpecifier *getQualifier() const {
+ return getQualifierLoc().getNestedNameSpecifier();
+ }
- /// Retrieve the first part of the nested-name-specifier that was
- /// found in the scope of the member access expression when the member access
- /// was initially parsed.
- ///
- /// This function only returns a useful result when member access expression
- /// uses a qualified member name, e.g., "x.Base::f". Here, the declaration
- /// returned by this function describes what was found by unqualified name
- /// lookup for the identifier "Base" within the scope of the member access
- /// expression itself. At template instantiation time, this information is
- /// combined with the results of name lookup into the type of the object
- /// expression itself (the class type of x).
- NamedDecl *getFirstQualifierFoundInScope() const {
- if (!hasFirstQualifierFoundInScope())
- return nullptr;
- return *getTrailingObjects<NamedDecl *>();
+ /// Retrieve the declarations found by unqualified lookup for the first
+ /// component name of the nested-name-specifier, if any.
+ ArrayRef<DeclAccessPair> unqualified_lookups() const {
+ if (!getNumUnqualifiedLookups())
+ return std::nullopt;
+ return {getTrailingObjects<DeclAccessPair>(), getNumUnqualifiedLookups()};
}
/// Retrieve the name of the member that this expression refers to.
diff --git a/clang/include/clang/AST/Stmt.h b/clang/include/clang/AST/Stmt.h
index 9cd7a364cd3f1..257a61c97c9c6 100644
--- a/clang/include/clang/AST/Stmt.h
+++ b/clang/include/clang/AST/Stmt.h
@@ -1020,18 +1020,19 @@ class alignas(void *) Stmt {
LLVM_PREFERRED_TYPE(bool)
unsigned IsArrow : 1;
+ /// True if this member expression used a nested-name-specifier to
+ /// refer to the member, e.g., "x->Base::f".
+ LLVM_PREFERRED_TYPE(bool)
+ unsigned HasQualifier : 1;
+
/// Whether this member expression has info for explicit template
/// keyword and arguments.
LLVM_PREFERRED_TYPE(bool)
unsigned HasTemplateKWAndArgsInfo : 1;
- /// See getFirstQualifierFoundInScope() and the comment listing
- /// the trailing objects.
- LLVM_PREFERRED_TYPE(bool)
- unsigned HasFirstQualifierFoundInScope : 1;
-
- /// The location of the '->' or '.' operator.
- SourceLocation OperatorLoc;
+ /// Number of declarations found by unqualified lookup for the
+ /// first component name of the nested-name-specifier.
+ unsigned NumUnqualifiedLookups;
};
class OverloadExprBitfields {
diff --git a/clang/include/clang/AST/UnresolvedSet.h b/clang/include/clang/AST/UnresolvedSet.h
index 1369725ab4e96..ef44499ce5926 100644
--- a/clang/include/clang/AST/UnresolvedSet.h
+++ b/clang/include/clang/AST/UnresolvedSet.h
@@ -97,6 +97,10 @@ class UnresolvedSetImpl {
decls().push_back(DeclAccessPair::make(D, AS));
}
+ void addAllDecls(ArrayRef<DeclAccessPair> Other) {
+ append(iterator(Other.begin()), iterator(Other.end()));
+ }
+
/// Replaces the given declaration with the new one, once.
///
/// \return true if the set changed
diff --git a/clang/include/clang/Basic/DiagnosticParseKinds.td b/clang/include/clang/Basic/DiagnosticParseKinds.td
index 12aab09f28556..0bd2e35bf2e31 100644
--- a/clang/include/clang/Basic/DiagnosticParseKinds.td
+++ b/clang/include/clang/Basic/DiagnosticParseKinds.td
@@ -895,9 +895,7 @@ def missing_template_arg_list_after_template_kw : Extension<
"keyword">, InGroup<DiagGroup<"missing-template-arg-list-after-template-kw">>,
DefaultError;
-def err_missing_dependent_template_keyword : Error<
- "use 'template' keyword to treat '%0' as a dependent template name">;
-def warn_missing_dependent_template_keyword : ExtWarn<
+def ext_missing_dependent_template_keyword : ExtWarn<
"use 'template' keyword to treat '%0' as a dependent template name">;
def ext_extern_template : Extension<
diff --git a/clang/include/clang/Parse/Parser.h b/clang/include/clang/Parse/Parser.h
index 6880fa4bb0b03..b4f5270a35956 100644
--- a/clang/include/clang/Parse/Parser.h
+++ b/clang/include/clang/Parse/Parser.h
@@ -3368,15 +3368,11 @@ class Parser : public CodeCompletionHandler {
BaseResult ParseBaseSpecifier(Decl *ClassDecl);
AccessSpecifier getAccessSpecifierIfPresent() const;
- bool ParseUnqualifiedIdTemplateId(CXXScopeSpec &SS,
- ParsedType ObjectType,
- bool ObjectHadErrors,
- SourceLocation TemplateKWLoc,
- IdentifierInfo *Name,
- SourceLocation NameLoc,
- bool EnteringContext,
- UnqualifiedId &Id,
- bool AssumeTemplateId);
+ bool ParseUnqualifiedIdTemplateId(
+ CXXScopeSpec &SS, ParsedType ObjectType, bool ObjectHadErrors,
+ SourceLocation TemplateKWLoc, SourceLocation TildeLoc,
+ IdentifierInfo *Name, SourceLocation NameLoc, bool EnteringContext,
+ UnqualifiedId &Id, bool AssumeTemplateId);
bool ParseUnqualifiedIdOperator(CXXScopeSpec &SS, bool EnteringContext,
ParsedType ObjectType,
UnqualifiedId &Result);
diff --git a/clang/include/clang/Sema/DeclSpec.h b/clang/include/clang/Sema/DeclSpec.h
index 425b6e2a0b30c..9c22c35535ede 100644
--- a/clang/include/clang/Sema/DeclSpec.h
+++ b/clang/include/clang/Sema/DeclSpec.h
@@ -75,6 +75,7 @@ class CXXScopeSpec {
SourceRange Range;
NestedNameSpecifierLocBuilder Builder;
ArrayRef<TemplateParameterList *> TemplateParamLists;
+ ArrayRef<DeclAccessPair> UnqualifiedLookups;
public:
SourceRange getRange() const { return Range; }
@@ -91,6 +92,13 @@ class CXXScopeSpec {
return TemplateParamLists;
}
+ void setUnqualifiedLookups(ArrayRef<DeclAccessPair> Found) {
+ UnqualifiedLookups = Found;
+ }
+ ArrayRef<DeclAccessPair> getUnqualifiedLookups() const {
+ return UnqualifiedLookups;
+ }
+
/// Retrieve the representation of the nested-name-specifier.
NestedNameSpecifier *getScopeRep() const {
return Builder.getRepresentation();
diff --git a/clang/include/clang/Sema/Lookup.h b/clang/include/clang/Sema/Lookup.h
index b0a08a05ac6a0..6b765ef3c980f 100644
--- a/clang/include/clang/Sema/Lookup.h
+++ b/clang/include/clang/Sema/Lookup.h
@@ -483,11 +483,15 @@ class LookupResult {
ResultKind = Found;
}
+ void addAllDecls(ArrayRef<DeclAccessPair> Other) {
+ Decls.addAllDecls(Other);
+ ResultKind = Found;
+ }
+
/// Add all the declarations from another set of lookup
/// results.
void addAllDecls(const LookupResult &Other) {
- Decls.append(Other.Decls.begin(), Other.Decls.end());
- ResultKind = Found;
+ addAllDecls(Other.Decls.pairs());
}
/// Determine whether no result was found because we could not
diff --git a/clang/include/clang/Sema/Sema.h b/clang/include/clang/Sema/Sema.h
index 57994f4033922..6be6f6725e5b7 100644
--- a/clang/include/clang/Sema/Sema.h
+++ b/clang/include/clang/Sema/Sema.h
@@ -2802,7 +2802,8 @@ class Sema final : public SemaBase {
/// (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 *FindFirstQualifierInScope(Scope *S, NestedNameSpecifier *NNS);
+ bool LookupFirstQualifierInScope(Scope *S, NestedNameSpecifier *NNS,
+ UnresolvedSetImpl &R);
/// Keeps information about an identifier in a nested-name-spec.
///
@@ -2842,9 +2843,6 @@ class Sema final : public SemaBase {
/// \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 '::' -> ':'
@@ -2853,11 +2851,6 @@ class Sema final : public SemaBase {
/// 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
@@ -2866,7 +2859,6 @@ class Sema final : public SemaBase {
/// specifier.
bool BuildCXXNestedNameSpecifier(Scope *S, NestedNameSpecInfo &IdInfo,
bool EnteringContext, CXXScopeSpec &SS,
- NamedDecl *ScopeLookupResult,
bool ErrorRecoveryLookup,
bool *IsCorrectedToColon = nullptr,
bool OnlyNamespace = false);
@@ -8566,11 +8558,12 @@ class Sema final : public SemaBase {
const TemplateArgumentListInfo *TemplateArgs,
bool IsDefiniteInstance, const Scope *S);
- ExprResult ActOnDependentMemberExpr(
- Expr *Base, QualType BaseType, bool IsArrow, SourceLocation OpLoc,
- const CXXScopeSpec &SS, SourceLocation TemplateKWLoc,
- NamedDecl *FirstQualifierInScope, const DeclarationNameInfo &NameInfo,
- const TemplateArgumentListInfo *TemplateArgs);
+ ExprResult
+ ActOnDependentMemberExpr(Expr *Base, QualType BaseType, bool IsArrow,
+ SourceLocation OpLoc, const CXXScopeSpec &SS,
+ SourceLocation TemplateKWLoc,
+ const DeclarationNameInfo &NameInfo,
+ const TemplateArgumentListInfo *TemplateArgs);
/// The main callback when the parser finds something like
/// expression . [nested-name-specifier] identifier
@@ -8626,15 +8619,14 @@ class Sema final : public SemaBase {
ExprResult BuildMemberReferenceExpr(
Expr *Base, QualType BaseType, SourceLocation OpLoc, bool IsArrow,
CXXScopeSpec &SS, SourceLocation TemplateKWLoc,
- NamedDecl *FirstQualifierInScope, const DeclarationNameInfo &NameInfo,
+ const DeclarationNameInfo &NameInfo,
const TemplateArgumentListInfo *TemplateArgs, const Scope *S,
ActOnMemberAccessExtraArgs *ExtraArgs = nullptr);
ExprResult
BuildMemberReferenceExpr(Expr *Base, QualType BaseType, SourceLocation OpLoc,
bool IsArrow, const CXXScopeSpec &SS,
- SourceLocation TemplateKWLoc,
- NamedDecl *FirstQualifierInScope, LookupResult &R,
+ SourceLocation TemplateKWLoc, LookupResult &R,
const TemplateArgumentListInfo *TemplateArgs,
const Scope *S, bool SuppressQualifierCheck = false,
ActOnMemberAccessExtraArgs *ExtraArgs = nullptr);
@@ -11122,15 +11114,14 @@ class Sema final : public SemaBase {
QualType ObjectType, bool EnteringContext,
RequiredTemplateKind RequiredTemplate = SourceLocation(),
AssumedTemplateKind *ATK = nullptr,
- bool AllowTypoCorrection = true);
+ bool AllowTypoCorrection = true, bool MayBeNNS = false);
- TemplateNameKind isTemplateName(Scope *S, CXXScopeSpec &SS,
- bool hasTemplateKeyword,
- const UnqualifiedId &Name,
- ParsedType ObjectType, bool EnteringContext,
- TemplateTy &Template,
- bool &MemberOfUnknownSpecialization,
- bool Disambiguation = false);
+ TemplateNameKind
+ isTemplateName(Scope *S, CXXScopeSpec &SS, bool hasTemplateKeyword,
+ const UnqualifiedId &Name, ParsedType ObjectType,
+ bool EnteringContext, TemplateTy &Template,
+ bool &MemberOfUnknownSpecialization,
+ bool Disambiguation = false, bool MayBeNNS = false);
/// Try to resolve an undeclared template name as a type template.
///
@@ -11459,12 +11450,11 @@ class Sema final : public SemaBase {
/// For example, given "x.MetaFun::template apply", the scope specifier
/// \p SS will be "MetaFun::", \p TemplateKWLoc contains the location
/// of the "template" keyword, and "apply" is the \p Name.
- TemplateNameKind ActOnTemplateName(Scope *S, CXXScopeSpec &SS,
- SourceLocation TemplateKWLoc,
- const UnqualifiedId &Name,
- ParsedType ObjectType,
- bool EnteringContext, TemplateTy &Template,
- bool AllowInjectedClassName = false);
+ TemplateNameKind
+ ActOnTemplateName(Scope *S, CXXScopeSpec &SS, SourceLocation TemplateKWLoc,
+ const UnqualifiedId &Name, ParsedType ObjectType,
+ bool EnteringContext, TemplateTy &Temp...
[truncated]
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Endilll
reviewed
Jul 11, 2024
chapuni
approved these changes
Jul 11, 2024
|
LLVM Buildbot has detected a new failure on builder Full details are available at: https://lab.llvm.org/buildbot/#/builders/73/builds/1674 Here is the relevant piece of the build log for the reference: |
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This broke building abseil-cpp (cd75cb4ae32c46c84cef9a9c78b42174f22ed0ac as of writing). STR:
|
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Well, I guess this is working as intended, as adding |
|
@glandium Yes, clang considers |
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The sad part is that MSVC and some old versions of GCC don't like |
13 tasks
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Could we perhaps put this behind a flag to help with the transition? Some cases can already be silenced with -Wno-missing-dependent-template-keyword but cases like above in absl are hard errors and there are no workarounds. |
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I'm also seeing a hard "missing 'template' keyword prior to dependent template name" error when building the 510.parest_r benchmark from SPEC CPU 2017 |
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@opensdd You might want to know that CWG1835 is causing some disruption in the wild I wonder if we should consider deploying that change NOT as a DR such that it would only affect C++23+ conformance, |
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I believe it, although the alternative (having to write
If you think that would create fewer problems (like skew between libraries and their clients) than it solves, I'm not opposed to bringing that up in CWG. |
@hokein The problem with the non-type template case is that we would have to check the validity of constructs outside the potential template-argument-list in order to disambiguate. For example,
@cor3ntin Yes, this is what I was thinking and is the resolution I prefer. Alternatively we could have a flag to disable the new behavior (or a mix of both, e.g. enable the new behavior via a flag which defaults to ON in C++23+). |
|
Given the amount of pain involved, I think this should be applied as a C++23 change rather than applied as a DR. I'd like to avoid adding a feature flag for this if possible (I'd prefer warning-default-as-error instead, but that doesn't seem particularly plausible here), but the cross-compiler behavior story may be sufficiently painful to make it worth considering. |
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I sent an email to core. There seems to be some support to reconsider as gcc is having the same issue we are. I propose the following:
Hopefully this works for everyone. |
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@cor3ntin Well, if the alternative is not implementing the resolution at all I'll look into the feasibility of identifying missing Also, I replied to your post on the core reflector. I find it rather unlikely that CWG will implement a mitigation mechanism as doing so would effectively revert the resolution to CWG1835. |
|
I have a new branch ready where:
template<int I>
struct A {
int x;
};
template<int I>
struct B : A<I> {
void f() {
this->A<I>::f(); // with -std=c++20 and earlier: no error
// with -std=c++23 and later:
// error: no member named 'f' in the global namespace
// error: missing 'template' keyword prior to dependent template name 'A'
}
};WDYAT? |
We generally try to avoid issuing more than one error diagnostic for the same problem. Couldn't we instead issue a note |
|
Another option would be to apply the resolution to all modes, but recover and issue a warning instead of an error. |
@mizvekov Without unannotated tentative parsing (to be properly introduced by #96364), issuing a warning is infeasible. Either way, by the time we detect the error we could be who knows how deep into the second operand of a |
So when we are parsing Do you think that's workable? |
We already do that :) the problem is when what follows int x = 0;
template<int I>
struct f { };
template<typename T>
void g(T t)
{
t.f<0>::x; // could be interpreted as '((t.f) < 0) > (::x)'
} |
Sure, but before CWG1835, we would perform the lookup anyway and treat the So we could try to do this just as well if A doesn't unambiguously look like a template argument list. That seems better than not trying to apply the new rule at all. |
Hitting this same error compiling the ares emulator on 19. |
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Independent of the other issues, it looks like this also re-introduces #98878 |
@nico #98878 still occurs without this patch applied: struct A
{
void f();
};
template<typename T>
void g(T t)
{
using U = A; // clang 18.1: 'warning: unused type alias 'U''
t.U::f();
}I can address this in the next application of this patch |
I'm not sure I follow. If we "treat the |
Yes, in that case. But I am arguing for selectively applying it. I thought that could work, but I am not sure, that's what I am asking. |
|
@mizvekov Consider a slightly altered version of the motivating example in the DR: template<int I> void end();
template<typename T>
bool Foo(T it0, T it1)
{
return it0->end < it1->end || it0->end > it1->end;
}
|
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@sdkrystian Sure do. The offending code lives at https://github.com/ares-emulator/ares/blob/master/nall/shared-pointer.hpp The error reads: The offending code block: Errors on 19, does not error on 18.1.8. |
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@KyunLFA Could you send the commit hash of the clang build which you're using? I'm unable to reproduce the errors. |
Sure, it's 4321300 . Also, just to make sure, have you tried building the whole ares emulator project with |
|
No longer errors for me... |
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Reapplies #92957, fixing an instance where the
templatekeyword was missing prior to a dependent name inllvm/ADT/ArrayRef.h. An alias-declaration is used to work around a bug affecting GCC releases before 11.1 which rejects the use of thetemplatekeyword prior to the nested-name-specifier in the class member access (godbolt example here).