https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105220
Bug ID: 105220
Summary: Incorrect concept evaluation when friend class is
involved
Product: gcc
Version: 12.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: martin.koch at bachmann dot info
Target Milestone: ---
Assume we have a concept which checks whether a type implements a method foo:
template <typename T>
concept fooable = requires(const T &t) {
t.foo();
};
And a class makes use of this concept:
template <typename T>
requires fooable<T>
struct A<T> { ... }
And some other class declares A as a friend:
class B {
private:
friend struct A<B>;
void foo() const {
std::cout << "foo called" << std::endl;
}
};
In this case B is not considered "fooable" in the template specialization of
A<B>.
With clang it works fine. See: https://godbolt.org/z/8qWrPfd4b
