[Bug c++/116673] __builtin_launder accepts function pointers and void pointers

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116673

--- Comment #2 from Jonathan Wakely <redi at gcc dot gnu.org> ---
I don't remember why I did it that way rather than with static_assert in the
body of std::launder. I must hate fast compilations.