[Bug c++/59256] qualified name in friend function declaration doesn't match previous declaration in inline namespace

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=59256

--- Comment #16 from Jonathan Wakely <redi at gcc dot gnu.org> ---
The std::format case looks like this:

namespace x
{
  inline namespace v {

    namespace detail {
      template<class> struct bar;
    }

    template<class Arg>
      auto make(Arg);

    template<class T>
    class detail::bar {
      bar() { }

      template<class Arg>
        friend auto x::make(Arg);
    };

    template<class Arg>
      auto make(Arg)
      {
        detail::bar<Arg> b;
        return 1;
      }
  }
}
int main()
{
  return x::make(1);
}