[clang] Reapply "[Clang][Sema] Use the correct lookup context when building overloaded 'operator->' in the current instantiation (#104458)" (PR #109422)
via cfe-commits
cfe-commits at lists.llvm.org
Fri Sep 20 06:48:52 PDT 2024
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-clang
Author: Krystian Stasiowski (sdkrystian)
<details>
<summary>Changes</summary>
Reapplies #<!-- -->104458, fixing a bug that occurs when a templated class declares `operator->` to return a non-dependent class type.
---
Full diff: https://github.com/llvm/llvm-project/pull/109422.diff
6 Files Affected:
- (modified) clang/include/clang/Sema/Sema.h (+3-3)
- (modified) clang/lib/Sema/SemaExprCXX.cpp (+18-18)
- (modified) clang/lib/Sema/SemaExprMember.cpp (+4-2)
- (modified) clang/lib/Sema/SemaOverload.cpp (+19-5)
- (modified) clang/lib/Sema/TreeTransform.h (+6-2)
- (modified) clang/test/CXX/temp/temp.res/temp.dep/temp.dep.type/p4.cpp (+13-11)
``````````diff
diff --git a/clang/include/clang/Sema/Sema.h b/clang/include/clang/Sema/Sema.h
index 68c782a15c6f1b..c1afefd36ce0ce 100644
--- a/clang/include/clang/Sema/Sema.h
+++ b/clang/include/clang/Sema/Sema.h
@@ -10639,9 +10639,9 @@ class Sema final : public SemaBase {
/// BuildOverloadedArrowExpr - Build a call to an overloaded @c operator->
/// (if one exists), where @c Base is an expression of class type and
/// @c Member is the name of the member we're trying to find.
- ExprResult BuildOverloadedArrowExpr(Scope *S, Expr *Base,
- SourceLocation OpLoc,
- bool *NoArrowOperatorFound = nullptr);
+ ExprResult BuildOverloadedArrowExpr(Expr *Base, SourceLocation OpLoc,
+ bool *NoArrowOperatorFound,
+ bool &IsDependent);
ExprResult BuildCXXMemberCallExpr(Expr *Exp, NamedDecl *FoundDecl,
CXXConversionDecl *Method,
diff --git a/clang/lib/Sema/SemaExprCXX.cpp b/clang/lib/Sema/SemaExprCXX.cpp
index 14feafd1e6b17f..7f425b62b3e2cb 100644
--- a/clang/lib/Sema/SemaExprCXX.cpp
+++ b/clang/lib/Sema/SemaExprCXX.cpp
@@ -7966,18 +7966,6 @@ ExprResult Sema::ActOnStartCXXMemberReference(Scope *S, Expr *Base,
QualType BaseType = Base->getType();
MayBePseudoDestructor = false;
- if (BaseType->isDependentType()) {
- // If we have a pointer to a dependent type and are using the -> operator,
- // the object type is the type that the pointer points to. We might still
- // have enough information about that type to do something useful.
- if (OpKind == tok::arrow)
- if (const PointerType *Ptr = BaseType->getAs<PointerType>())
- BaseType = Ptr->getPointeeType();
-
- ObjectType = ParsedType::make(BaseType);
- MayBePseudoDestructor = true;
- return Base;
- }
// C++ [over.match.oper]p8:
// [...] When operator->returns, the operator-> is applied to the value
@@ -7992,7 +7980,8 @@ ExprResult Sema::ActOnStartCXXMemberReference(Scope *S, Expr *Base,
SmallVector<FunctionDecl*, 8> OperatorArrows;
CTypes.insert(Context.getCanonicalType(BaseType));
- while (BaseType->isRecordType()) {
+ while (
+ isa<InjectedClassNameType, RecordType>(BaseType.getCanonicalType())) {
if (OperatorArrows.size() >= getLangOpts().ArrowDepth) {
Diag(OpLoc, diag::err_operator_arrow_depth_exceeded)
<< StartingType << getLangOpts().ArrowDepth << Base->getSourceRange();
@@ -8002,15 +7991,26 @@ ExprResult Sema::ActOnStartCXXMemberReference(Scope *S, Expr *Base,
return ExprError();
}
+ bool IsDependent;
Result = BuildOverloadedArrowExpr(
- S, Base, OpLoc,
+ Base, OpLoc,
// When in a template specialization and on the first loop iteration,
// potentially give the default diagnostic (with the fixit in a
// separate note) instead of having the error reported back to here
// and giving a diagnostic with a fixit attached to the error itself.
(FirstIteration && CurFD && CurFD->isFunctionTemplateSpecialization())
? nullptr
- : &NoArrowOperatorFound);
+ : &NoArrowOperatorFound,
+ IsDependent);
+
+ if (IsDependent) {
+ // BuildOverloadedArrowExpr sets IsDependent to indicate that we need
+ // to build a dependent overloaded arrow expression.
+ assert(Base->isTypeDependent());
+ BaseType = Context.DependentTy;
+ break;
+ }
+
if (Result.isInvalid()) {
if (NoArrowOperatorFound) {
if (FirstIteration) {
@@ -8030,6 +8030,7 @@ ExprResult Sema::ActOnStartCXXMemberReference(Scope *S, Expr *Base,
}
return ExprError();
}
+
Base = Result.get();
if (CXXOperatorCallExpr *OpCall = dyn_cast<CXXOperatorCallExpr>(Base))
OperatorArrows.push_back(OpCall->getDirectCallee());
@@ -8067,7 +8068,7 @@ ExprResult Sema::ActOnStartCXXMemberReference(Scope *S, Expr *Base,
// it's legal for the type to be incomplete if this is a pseudo-destructor
// call. We'll do more incomplete-type checks later in the lookup process,
// so just skip this check for ObjC types.
- if (!BaseType->isRecordType()) {
+ if (BaseType->isDependentType() || !BaseType->isRecordType()) {
ObjectType = ParsedType::make(BaseType);
MayBePseudoDestructor = true;
return Base;
@@ -8078,8 +8079,7 @@ ExprResult Sema::ActOnStartCXXMemberReference(Scope *S, Expr *Base,
// Unlike the object expression in other contexts, *this is not required to
// be of complete type for purposes of class member access (5.2.5) outside
// the member function body.
- if (!BaseType->isDependentType() &&
- !isThisOutsideMemberFunctionBody(BaseType) &&
+ if (!isThisOutsideMemberFunctionBody(BaseType) &&
RequireCompleteType(OpLoc, BaseType,
diag::err_incomplete_member_access)) {
return CreateRecoveryExpr(Base->getBeginLoc(), Base->getEndLoc(), {Base});
diff --git a/clang/lib/Sema/SemaExprMember.cpp b/clang/lib/Sema/SemaExprMember.cpp
index f1ba26f38520a9..864e58cc7ee6ef 100644
--- a/clang/lib/Sema/SemaExprMember.cpp
+++ b/clang/lib/Sema/SemaExprMember.cpp
@@ -580,7 +580,9 @@ Sema::ActOnDependentMemberExpr(Expr *BaseExpr, QualType BaseType,
}
}
- assert(BaseType->isDependentType() || NameInfo.getName().isDependentName() ||
+ assert(BaseType->isDependentType() ||
+ (BaseExpr && BaseExpr->isTypeDependent()) ||
+ NameInfo.getName().isDependentName() ||
isDependentScopeSpecifier(SS) ||
(TemplateArgs && llvm::any_of(TemplateArgs->arguments(),
[](const TemplateArgumentLoc &Arg) {
@@ -1313,7 +1315,7 @@ static ExprResult LookupMemberExpr(Sema &S, LookupResult &R,
BaseType = Ptr->getPointeeType();
else if (BaseType->isFunctionType())
goto fail;
- else if (BaseType->isDependentType())
+ else if (BaseExpr.get()->isTypeDependent())
BaseType = S.Context.DependentTy;
else if (BaseType->isRecordType()) {
// Recover from arrow accesses to records, e.g.:
diff --git a/clang/lib/Sema/SemaOverload.cpp b/clang/lib/Sema/SemaOverload.cpp
index 861b0a91240b3b..6b91d4898674ec 100644
--- a/clang/lib/Sema/SemaOverload.cpp
+++ b/clang/lib/Sema/SemaOverload.cpp
@@ -15878,12 +15878,14 @@ Sema::BuildCallToObjectOfClassType(Scope *S, Expr *Obj,
return CheckForImmediateInvocation(MaybeBindToTemporary(TheCall), Method);
}
-ExprResult
-Sema::BuildOverloadedArrowExpr(Scope *S, Expr *Base, SourceLocation OpLoc,
- bool *NoArrowOperatorFound) {
- assert(Base->getType()->isRecordType() &&
+ExprResult Sema::BuildOverloadedArrowExpr(Expr *Base, SourceLocation OpLoc,
+ bool *NoArrowOperatorFound,
+ bool &IsDependent) {
+ assert(Base->getType()->getAsRecordDecl() &&
"left-hand side must have class type");
+ IsDependent = false;
+
if (checkPlaceholderForOverload(*this, Base))
return ExprError();
@@ -15904,7 +15906,19 @@ Sema::BuildOverloadedArrowExpr(Scope *S, Expr *Base, SourceLocation OpLoc,
return ExprError();
LookupResult R(*this, OpName, OpLoc, LookupOrdinaryName);
- LookupQualifiedName(R, Base->getType()->castAs<RecordType>()->getDecl());
+ LookupParsedName(R, /*S=*/nullptr, /*SS=*/nullptr, Base->getType());
+
+ // If the expression is dependent and we either:
+ // - found a member of the current instantiation named 'operator->', or
+ // - found nothing, and the lookup context has no dependent base classes
+ //
+ // then we should build a dependent class member access expression.
+ if (R.wasNotFoundInCurrentInstantiation() ||
+ (Base->isTypeDependent() && !R.empty())) {
+ IsDependent = true;
+ return Base;
+ }
+
R.suppressAccessDiagnostics();
for (LookupResult::iterator Oper = R.begin(), OperEnd = R.end();
diff --git a/clang/lib/Sema/TreeTransform.h b/clang/lib/Sema/TreeTransform.h
index 0daf620b4123e4..235b51a33babd5 100644
--- a/clang/lib/Sema/TreeTransform.h
+++ b/clang/lib/Sema/TreeTransform.h
@@ -16583,10 +16583,14 @@ ExprResult TreeTransform<Derived>::RebuildCXXOperatorCallExpr(
} else if (Op == OO_Arrow) {
// It is possible that the type refers to a RecoveryExpr created earlier
// in the tree transformation.
- if (First->getType()->isDependentType())
+ if (First->containsErrors())
return ExprError();
+ bool IsDependent;
// -> is never a builtin operation.
- return SemaRef.BuildOverloadedArrowExpr(nullptr, First, OpLoc);
+ ExprResult Result = SemaRef.BuildOverloadedArrowExpr(
+ First, OpLoc, /*NoArrowOperatorFound=*/nullptr, IsDependent);
+ assert(!IsDependent);
+ return Result;
} else if (Second == nullptr || isPostIncDec) {
if (!First->getType()->isOverloadableType() ||
(Op == OO_Amp && getSema().isQualifiedMemberAccess(First))) {
diff --git a/clang/test/CXX/temp/temp.res/temp.dep/temp.dep.type/p4.cpp b/clang/test/CXX/temp/temp.res/temp.dep/temp.dep.type/p4.cpp
index f32f49ef4539a5..89c22a0bc137d9 100644
--- a/clang/test/CXX/temp/temp.res/temp.dep/temp.dep.type/p4.cpp
+++ b/clang/test/CXX/temp/temp.res/temp.dep/temp.dep.type/p4.cpp
@@ -484,16 +484,19 @@ namespace N4 {
template<typename T>
struct A {
void not_instantiated(A a, A<T> b, T c) {
- a->x;
- b->x;
+ a->x; // expected-error {{member reference type 'A<T>' is not a pointer; did you mean to use '.'?}}
+ b->x; // expected-error {{member reference type 'A<T>' is not a pointer; did you mean to use '.'?}}
c->x;
}
void instantiated(A a, A<T> b, T c) {
- a->x; // expected-error {{member reference type 'A<int>' is not a pointer; did you mean to use '.'?}}
- // expected-error at -1 {{no member named 'x' in 'N4::A<int>'}}
- b->x; // expected-error {{member reference type 'A<int>' is not a pointer; did you mean to use '.'?}}
- // expected-error at -1 {{no member named 'x' in 'N4::A<int>'}}
+ // FIXME: We should only emit a single diagnostic suggesting to use '.'!
+ a->x; // expected-error {{member reference type 'A<T>' is not a pointer; did you mean to use '.'?}}
+ // expected-error at -1 {{member reference type 'A<int>' is not a pointer; did you mean to use '.'?}}
+ // expected-error at -2 {{no member named 'x' in 'N4::A<int>'}}
+ b->x; // expected-error {{member reference type 'A<T>' is not a pointer; did you mean to use '.'?}}
+ // expected-error at -1 {{member reference type 'A<int>' is not a pointer; did you mean to use '.'?}}
+ // expected-error at -2 {{no member named 'x' in 'N4::A<int>'}}
c->x; // expected-error {{member reference type 'int' is not a pointer}}
}
};
@@ -540,11 +543,10 @@ namespace N4 {
a->T::f();
a->T::g();
- // FIXME: 'U' should be a dependent name, and its lookup context should be 'a.operator->()'!
- a->U::x; // expected-error {{use of undeclared identifier 'U'}}
- a->U::y; // expected-error {{use of undeclared identifier 'U'}}
- a->U::f(); // expected-error {{use of undeclared identifier 'U'}}
- a->U::g(); // expected-error {{use of undeclared identifier 'U'}}
+ a->U::x;
+ a->U::y;
+ a->U::f();
+ a->U::g();
}
void instantiated(D a) {
``````````
</details>
https://github.com/llvm/llvm-project/pull/109422
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