https://gcc.gnu.org/bugzilla/show_bug.cgi?id=121351
Bug ID: 121351
Summary: [15/16 Regression] Ambiguous resolution of constrained
overloads imported from base class
Product: gcc
Version: 15.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: moncef.mechri at gmail dot com
Target Milestone: ---
Consider the following code:
#include <concepts>
template<class D>
struct Base {
void FooIntegral() { static_cast<D*>(this)->Foo(42); }
void Foo(std::integral auto a) {}
};
struct Derived : Base<Derived> {
using Base::Foo;
void Foo(std::integral auto a) {}
};
int main() {
Derived d;
d.FooIntegral();
}
This code is accepted by GCC < 15, clang 20.1.0, MSVC 19, and EDG 6.7 (in GNU
mode)
However, GCC 15 and trunk reject this code with the following error:
<source>: In instantiation of 'void Base<D>::FooIntegral() [with D = Derived]':
<source>:18:18: required from here
18 | d.FooIntegral();
| ~~~~~~~~~~~~~^~
<source>:5:52: error: call of overloaded 'Foo(int)' is ambiguous
5 | void FooIntegral() { static_cast<D*>(this)->Foo(42); }
| ~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~
<source>:5:52: note: there are 2 candidates
<source>:7:10: note: candidate 1: 'void Base<D>::Foo(auto:1) [with auto:1 =
int; D = Derived]'
7 | void Foo(std::integral auto a) {}
| ^~~
<source>:13:10: note: candidate 2: 'void Derived::Foo(auto:2) [with auto:2 =
int]'
13 | void Foo(std::integral auto a) {}
| ^~~
Demo: https://godbolt.org/z/1v9czGEf8
I also noticed that the error disappears if I remove mentions of std::integral
in the above code.
Possibly related to https://gcc.gnu.org/bugzilla/show_bug.cgi?id=119859
