[Bug c++/119259] compilation error: *constexpr* operator==(const T&) const = default` forces compilation of std::vector's operator== function

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=119259

--- Comment #7 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
I am suspecting GCC doing the correct thing.

In my last reduced testcase, move intermidiate below not_equatable and change
the type of the field t to not_equatable and see that all 3 now reject the
code.