https://github.com/cor3ntin updated
https://github.com/llvm/llvm-project/pull/148613
>From d782c0b1ab000d3ff8573a60ed978cced4df3a66 Mon Sep 17 00:00:00 2001
From: Corentin Jabot <corentinja...@gmail.com>
Date: Mon, 14 Jul 2025 13:34:26 +0200
Subject: [PATCH] [Clang] Do not treat Foo -> const Foo conversion sequences as
perfect
For implicit object arguments.
This fixes a regression introduced by the "perfect match"
overload resolusion mechanism introduced in #8c5a307.
Note that GCC allows the ambiguity between a const and non-const
candidate to be resolved. But this patch focuses on restoring the
Clang 20 behavior, and to fix the cases which we did resolve
incorrectly.
Fixes #147374
---
clang/include/clang/Sema/Overload.h | 11 ++++++--
clang/lib/Sema/SemaOverload.cpp | 14 +++++++++-
...overload-resolution-deferred-templates.cpp | 28 +++++++++++++++++++
3 files changed, 49 insertions(+), 4 deletions(-)
diff --git a/clang/include/clang/Sema/Overload.h
b/clang/include/clang/Sema/Overload.h
index a70335bef9dd4..9135ff949eeab 100644
--- a/clang/include/clang/Sema/Overload.h
+++ b/clang/include/clang/Sema/Overload.h
@@ -350,6 +350,11 @@ class Sema;
LLVM_PREFERRED_TYPE(bool)
unsigned BindsToRvalue : 1;
+ /// Whether this was an identity conversion with qualification
+ /// conversion for the implicit object argument.
+ LLVM_PREFERRED_TYPE(bool)
+ unsigned IsImplicitObjectArgumentQualificationConversion : 1;
+
/// Whether this binds an implicit object argument to a
/// non-static member function without a ref-qualifier.
LLVM_PREFERRED_TYPE(bool)
@@ -448,11 +453,11 @@ class Sema;
#endif
return true;
}
- if (!C.hasSameType(getFromType(), getToType(2)))
- return false;
if (BindsToRvalue && IsLvalueReference)
return false;
- return true;
+ if (IsImplicitObjectArgumentQualificationConversion)
+ return C.hasSameUnqualifiedType(getFromType(), getToType(2));
+ return C.hasSameType(getFromType(), getToType(2));
}
ImplicitConversionRank getRank() const;
diff --git a/clang/lib/Sema/SemaOverload.cpp b/clang/lib/Sema/SemaOverload.cpp
index 7af3acacb5ba6..a6958004e41f7 100644
--- a/clang/lib/Sema/SemaOverload.cpp
+++ b/clang/lib/Sema/SemaOverload.cpp
@@ -245,6 +245,7 @@ void StandardConversionSequence::setAsIdentityConversion() {
IsLvalueReference = true;
BindsToFunctionLvalue = false;
BindsToRvalue = false;
+ IsImplicitObjectArgumentQualificationConversion = false;
BindsImplicitObjectArgumentWithoutRefQualifier = false;
ObjCLifetimeConversionBinding = false;
FromBracedInitList = false;
@@ -5317,6 +5318,7 @@ TryReferenceInit(Sema &S, Expr *Init, QualType DeclType,
ICS.Standard.DirectBinding = BindsDirectly;
ICS.Standard.IsLvalueReference = !isRValRef;
ICS.Standard.BindsToFunctionLvalue = T2->isFunctionType();
+ ICS.Standard.IsImplicitObjectArgumentQualificationConversion = false;
ICS.Standard.BindsToRvalue = InitCategory.isRValue();
ICS.Standard.BindsImplicitObjectArgumentWithoutRefQualifier = false;
ICS.Standard.ObjCLifetimeConversionBinding =
@@ -5496,6 +5498,7 @@ TryReferenceInit(Sema &S, Expr *Init, QualType DeclType,
ICS.Standard.IsLvalueReference = !isRValRef;
ICS.Standard.BindsToFunctionLvalue = false;
ICS.Standard.BindsToRvalue = true;
+ ICS.Standard.IsImplicitObjectArgumentQualificationConversion = false;
ICS.Standard.BindsImplicitObjectArgumentWithoutRefQualifier = false;
ICS.Standard.ObjCLifetimeConversionBinding = false;
} else if (ICS.isUserDefined()) {
@@ -5518,6 +5521,8 @@ TryReferenceInit(Sema &S, Expr *Init, QualType DeclType,
ICS.UserDefined.After.IsLvalueReference = !isRValRef;
ICS.UserDefined.After.BindsToFunctionLvalue = false;
ICS.UserDefined.After.BindsToRvalue = !LValRefType;
+ ICS.UserDefined.After.IsImplicitObjectArgumentQualificationConversion =
+ false;
ICS.UserDefined.After.BindsImplicitObjectArgumentWithoutRefQualifier =
false;
ICS.UserDefined.After.ObjCLifetimeConversionBinding = false;
ICS.UserDefined.After.FromBracedInitList = false;
@@ -5802,6 +5807,7 @@ TryListConversion(Sema &S, InitListExpr *From, QualType
ToType,
StandardConversionSequence &SCS = Result.isStandard() ? Result.Standard :
Result.UserDefined.After;
SCS.ReferenceBinding = true;
+ SCS.IsImplicitObjectArgumentQualificationConversion = false;
SCS.IsLvalueReference = ToType->isLValueReferenceType();
SCS.BindsToRvalue = true;
SCS.BindsToFunctionLvalue = false;
@@ -5999,8 +6005,12 @@ static ImplicitConversionSequence
TryObjectArgumentInitialization(
// affects the conversion rank.
QualType ClassTypeCanon = S.Context.getCanonicalType(ClassType);
ImplicitConversionKind SecondKind;
- if (ClassTypeCanon == FromTypeCanon.getLocalUnqualifiedType()) {
+ bool IsQualificationConversion = false;
+ if (ImplicitParamType.getCanonicalType() == FromTypeCanon) {
SecondKind = ICK_Identity;
+ } else if (ClassTypeCanon == FromTypeCanon.getLocalUnqualifiedType()) {
+ SecondKind = ICK_Identity;
+ IsQualificationConversion = true;
} else if (S.IsDerivedFrom(Loc, FromType, ClassType)) {
SecondKind = ICK_Derived_To_Base;
} else if (!Method->isExplicitObjectMemberFunction()) {
@@ -6041,6 +6051,8 @@ static ImplicitConversionSequence
TryObjectArgumentInitialization(
ICS.Standard.setFromType(FromType);
ICS.Standard.setAllToTypes(ImplicitParamType);
ICS.Standard.ReferenceBinding = true;
+ ICS.Standard.IsImplicitObjectArgumentQualificationConversion =
+ IsQualificationConversion;
ICS.Standard.DirectBinding = true;
ICS.Standard.IsLvalueReference = Method->getRefQualifier() != RQ_RValue;
ICS.Standard.BindsToFunctionLvalue = false;
diff --git a/clang/test/SemaCXX/overload-resolution-deferred-templates.cpp
b/clang/test/SemaCXX/overload-resolution-deferred-templates.cpp
index 46c3670848529..135865c8450f5 100644
--- a/clang/test/SemaCXX/overload-resolution-deferred-templates.cpp
+++ b/clang/test/SemaCXX/overload-resolution-deferred-templates.cpp
@@ -283,3 +283,31 @@ void f() {
}
#endif
+
+namespace GH147374 {
+
+struct String {};
+template <typename T> void operator+(T, String &&) = delete;
+
+struct Bar {
+ void operator+(String) const; // expected-note {{candidate function}}
+ friend void operator+(Bar, String) {}; // expected-note {{candidate
function}}
+};
+
+struct Baz {
+ void operator+(String); // expected-note {{candidate function}}
+ friend void operator+(Baz, String) {}; // expected-note {{candidate
function}}
+};
+
+void test() {
+ Bar a;
+ String b;
+ a + b;
+ //expected-error@-1 {{use of overloaded operator '+' is ambiguous (with
operand types 'Bar' and 'String')}}
+
+ Baz z;
+ z + b;
+ //expected-error@-1 {{use of overloaded operator '+' is ambiguous (with
operand types 'Baz' and 'String')}}
+}
+
+}
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