[Bug c++/122550] template friend function is ambiguous with g++ 14

[pinskia at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=122550

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Reduced to:
```
class Hasher;
template <class a>
concept C = true;

template<C UnsignedInteger>
void add(Hasher&, UnsignedInteger);

class Hasher {
    template<C UnsignedInteger>
    friend void add(Hasher& hasher, UnsignedInteger integer) { }
};

void f(Hasher& hasher, unsigned long integer)
{
    add(hasher, unsigned(integer));
}
```