https://github.com/cor3ntin updated
https://github.com/llvm/llvm-project/pull/149504
>From f34d340f59e742f6e75397043b0bed8faed7d94a Mon Sep 17 00:00:00 2001
From: Corentin Jabot <corentinja...@gmail.com>
Date: Fri, 18 Jul 2025 10:27:44 +0200
Subject: [PATCH 1/2] [Clang] Do not assume a perfect match is a better match
than a non-template non-perfect match.
This fixes a regression introduced by the "perfect match" overload
resolution mechanism introduced in 8c5a307.
Fixes #147374
---
clang/include/clang/Sema/Overload.h | 2 -
clang/lib/Sema/SemaOverload.cpp | 51 +++----------------
...overload-resolution-deferred-templates.cpp | 28 ++++++++++
3 files changed, 35 insertions(+), 46 deletions(-)
diff --git a/clang/include/clang/Sema/Overload.h
b/clang/include/clang/Sema/Overload.h
index a70335bef9dd4..d34a4146ddbd6 100644
--- a/clang/include/clang/Sema/Overload.h
+++ b/clang/include/clang/Sema/Overload.h
@@ -1491,8 +1491,6 @@ class Sema;
OverloadingResult
BestViableFunctionImpl(Sema &S, SourceLocation Loc,
OverloadCandidateSet::iterator &Best);
- void PerfectViableFunction(Sema &S, SourceLocation Loc,
- OverloadCandidateSet::iterator &Best);
};
bool isBetterOverloadCandidate(Sema &S, const OverloadCandidate &Cand1,
diff --git a/clang/lib/Sema/SemaOverload.cpp b/clang/lib/Sema/SemaOverload.cpp
index 1b54628c5e564..cf9bd1b71ba63 100644
--- a/clang/lib/Sema/SemaOverload.cpp
+++ b/clang/lib/Sema/SemaOverload.cpp
@@ -11353,56 +11353,19 @@ OverloadingResult
OverloadCandidateSet::BestViableFunction(Sema &S,
bool TwoPhaseResolution =
DeferredCandidatesCount != 0 && !ResolutionByPerfectCandidateIsDisabled;
- if (TwoPhaseResolution) {
-
- PerfectViableFunction(S, Loc, Best);
- if (Best != end())
- return ResultForBestCandidate(Best);
+ if(TwoPhaseResolution) {
+ OverloadingResult Res = BestViableFunctionImpl(S, Loc, Best);
+ if (Best != end() && Best->isPerfectMatch(S.Context)) {
+ if(!(HasDeferredTemplateConstructors &&
+ isa_and_nonnull<CXXConversionDecl>(Best->Function)))
+ return Res;
+ }
}
InjectNonDeducedTemplateCandidates(S);
return BestViableFunctionImpl(S, Loc, Best);
}
-void OverloadCandidateSet::PerfectViableFunction(
- Sema &S, SourceLocation Loc, OverloadCandidateSet::iterator &Best) {
-
- Best = end();
- for (auto It = Candidates.begin(); It != Candidates.end(); ++It) {
-
- if (!It->isPerfectMatch(S.getASTContext()))
- continue;
-
- // We found a suitable conversion function
- // but if there is a template constructor in the target class
- // we might prefer that instead.
- if (HasDeferredTemplateConstructors &&
- isa_and_nonnull<CXXConversionDecl>(It->Function)) {
- Best = end();
- break;
- }
-
- if (Best == end()) {
- Best = It;
- continue;
- }
- if (Best->Function && It->Function) {
- FunctionDecl *D =
- S.getMoreConstrainedFunction(Best->Function, It->Function);
- if (D == nullptr) {
- Best = end();
- break;
- }
- if (D == It->Function)
- Best = It;
- continue;
- }
- // ambiguous
- Best = end();
- break;
- }
-}
-
OverloadingResult OverloadCandidateSet::BestViableFunctionImpl(
Sema &S, SourceLocation Loc, OverloadCandidateSet::iterator &Best) {
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')}}
+}
+
+}
>From fc04ac640d87718c98f0c0bf7868b993f6fde96d Mon Sep 17 00:00:00 2001
From: Corentin Jabot <corentinja...@gmail.com>
Date: Fri, 18 Jul 2025 14:29:52 +0200
Subject: [PATCH 2/2] format
---
clang/lib/Sema/SemaOverload.cpp | 14 +++++++-------
1 file changed, 7 insertions(+), 7 deletions(-)
diff --git a/clang/lib/Sema/SemaOverload.cpp b/clang/lib/Sema/SemaOverload.cpp
index cf9bd1b71ba63..5dd5b495480d9 100644
--- a/clang/lib/Sema/SemaOverload.cpp
+++ b/clang/lib/Sema/SemaOverload.cpp
@@ -11353,13 +11353,13 @@ OverloadingResult
OverloadCandidateSet::BestViableFunction(Sema &S,
bool TwoPhaseResolution =
DeferredCandidatesCount != 0 && !ResolutionByPerfectCandidateIsDisabled;
- if(TwoPhaseResolution) {
- OverloadingResult Res = BestViableFunctionImpl(S, Loc, Best);
- if (Best != end() && Best->isPerfectMatch(S.Context)) {
- if(!(HasDeferredTemplateConstructors &&
- isa_and_nonnull<CXXConversionDecl>(Best->Function)))
- return Res;
- }
+ if (TwoPhaseResolution) {
+ OverloadingResult Res = BestViableFunctionImpl(S, Loc, Best);
+ if (Best != end() && Best->isPerfectMatch(S.Context)) {
+ if (!(HasDeferredTemplateConstructors &&
+ isa_and_nonnull<CXXConversionDecl>(Best->Function)))
+ return Res;
+ }
}
InjectNonDeducedTemplateCandidates(S);
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