https://github.com/offsetof updated
https://github.com/llvm/llvm-project/pull/132830
>From e458a6b79f560e803bdce414ea35f147ee4ce39d Mon Sep 17 00:00:00 2001
From: offsetof <offse...@mailo.com>
Date: Mon, 24 Mar 2025 21:06:44 +0000
Subject: [PATCH 1/2] [clang] Fix overload resolution ranking of inherited
constructors
Take parameter types of candidate constructors into account when
deciding whether to apply the tiebreaker.
---
clang/docs/ReleaseNotes.rst | 3 +++
clang/lib/Sema/SemaOverload.cpp | 17 ++++++++---------
clang/test/CXX/drs/cwg22xx.cpp | 14 ++++++++++++++
3 files changed, 25 insertions(+), 9 deletions(-)
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index f919b66dd0e41..a3d882312056c 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -358,6 +358,9 @@ Bug Fixes to C++ Support
- Fixed a Clang regression in C++20 mode where unresolved dependent call
expressions were created inside non-dependent contexts (#GH122892)
- Clang now emits the ``-Wunused-variable`` warning when some structured
bindings are unused
and the ``[[maybe_unused]]`` attribute is not applied. (#GH125810)
+- Overload resolution tiebreaker for inherited constructors is now only
+ applied if their parameters have the same type, as required by the C++
+ standard. (#GH121331)
Bug Fixes to AST Handling
^^^^^^^^^^^^^^^^^^^^^^^^^
diff --git a/clang/lib/Sema/SemaOverload.cpp b/clang/lib/Sema/SemaOverload.cpp
index 6d8006b35dcf4..f35d272b470cb 100644
--- a/clang/lib/Sema/SemaOverload.cpp
+++ b/clang/lib/Sema/SemaOverload.cpp
@@ -40,6 +40,7 @@
#include "llvm/ADT/ScopeExit.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/SmallVector.h"
+#include "llvm/Support/Casting.h"
#include <algorithm>
#include <cassert>
#include <cstddef>
@@ -10724,15 +10725,13 @@ bool clang::isBetterOverloadCandidate(
// -- F1 is a constructor for a class D, F2 is a constructor for a base
// class B of D, and for all arguments the corresponding parameters of
// F1 and F2 have the same type.
- // FIXME: Implement the "all parameters have the same type" check.
- bool Cand1IsInherited =
- isa_and_nonnull<ConstructorUsingShadowDecl>(Cand1.FoundDecl.getDecl());
- bool Cand2IsInherited =
- isa_and_nonnull<ConstructorUsingShadowDecl>(Cand2.FoundDecl.getDecl());
- if (Cand1IsInherited != Cand2IsInherited)
- return Cand2IsInherited;
- else if (Cand1IsInherited) {
- assert(Cand2IsInherited);
+ if (isa_and_nonnull<CXXConstructorDecl>(Cand1.Function) &&
+ isa_and_nonnull<CXXConstructorDecl>(Cand2.Function) &&
+ llvm::equal(Cand1.Function->parameters().take_front(NumArgs),
+ Cand2.Function->parameters().take_front(NumArgs),
+ [&](ParmVarDecl *P1, ParmVarDecl *P2) {
+ return S.Context.hasSameUnqualifiedType(P1->getType(),
P2->getType());
+ })) {
auto *Cand1Class = cast<CXXRecordDecl>(Cand1.Function->getDeclContext());
auto *Cand2Class = cast<CXXRecordDecl>(Cand2.Function->getDeclContext());
if (Cand1Class->isDerivedFrom(Cand2Class))
diff --git a/clang/test/CXX/drs/cwg22xx.cpp b/clang/test/CXX/drs/cwg22xx.cpp
index 8c8ad9f7f74ee..43bab3da171e4 100644
--- a/clang/test/CXX/drs/cwg22xx.cpp
+++ b/clang/test/CXX/drs/cwg22xx.cpp
@@ -169,6 +169,20 @@ B b;
// since-cxx11-error@-1 {{call to implicitly-deleted default constructor of
'B'}}
// since-cxx11-note@#cwg2273-B {{default constructor of 'B' is implicitly
deleted because base class 'A' has a deleted default constructor}}
// since-cxx11-note@#cwg2273-A {{'A' has been explicitly marked deleted
here}}
+
+struct X {
+ X(float); // since-cxx11-note {{candidate inherited constructor}}
+ X(void*, int = 0) = delete;
+};
+
+struct Y : X {
+ using X::X; // since-cxx11-note {{constructor from base class 'X' inherited
here}}
+ Y(double); // since-cxx11-note {{candidate constructor}}
+ Y(void* const, long = 1);
+};
+
+Y y = 1; // since-cxx11-error {{conversion from 'int' to 'Y' is ambiguous}}
+Y z = nullptr;
#endif
} // namespace cwg2273
>From bd15fc45015c79c21c62295677644e2f1d72fbe4 Mon Sep 17 00:00:00 2001
From: offsetof <offse...@mailo.com>
Date: Mon, 24 Mar 2025 21:26:58 +0000
Subject: [PATCH 2/2] fixup! [clang] Fix overload resolution ranking of
inherited constructors
Fix formatting
---
clang/lib/Sema/SemaOverload.cpp | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/clang/lib/Sema/SemaOverload.cpp b/clang/lib/Sema/SemaOverload.cpp
index f35d272b470cb..8e594753d261e 100644
--- a/clang/lib/Sema/SemaOverload.cpp
+++ b/clang/lib/Sema/SemaOverload.cpp
@@ -10730,7 +10730,8 @@ bool clang::isBetterOverloadCandidate(
llvm::equal(Cand1.Function->parameters().take_front(NumArgs),
Cand2.Function->parameters().take_front(NumArgs),
[&](ParmVarDecl *P1, ParmVarDecl *P2) {
- return S.Context.hasSameUnqualifiedType(P1->getType(),
P2->getType());
+ return S.Context.hasSameUnqualifiedType(P1->getType(),
+ P2->getType());
})) {
auto *Cand1Class = cast<CXXRecordDecl>(Cand1.Function->getDeclContext());
auto *Cand2Class = cast<CXXRecordDecl>(Cand2.Function->getDeclContext());
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