[Bug libstdc++/121858] function_ref(nontype_t<__fn>, _Up&& __ref) did not consider that _Up is a reference_wrapper

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=121858

--- Comment #5 from Tomasz Kamiński <tkaminsk at gcc dot gnu.org> ---
For member pointer type P being M C::*, std::invokable_v<P, R, Args...> is only
valid if R is reference to C or object derived from it, or reference_wrapper of
such.
So I think I could as QoI use sr.get() for std::nontype<&S::f>.