[Bug c++/105865] false positive non-consant expression: static_cast pointer-to-member upcast in constexpr constructor

[acox at reliablecontrols dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105865

--- Comment #1 from Alec <acox at reliablecontrols dot com> ---
It also works when trying to use a template helper outside of the constructor
See the example here https://godbolt.org/z/3raenhnjr