https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97518
--- Comment #2 from Jonathan Wakely <redi at gcc dot gnu.org> --- A related case I encounter often is: static_assert( sizeof(T) == 4 ); if the assertion fails I would like to know what the size is, rather than just "not 4", so I have to add something like Barry's verify_same: template<size_t> struct undefined; undefined<sizeof(T)> _; and read the diagnostics. If static_assert was able to tell me it failed because 8 == 4 failed, that would be awesome. Concepts do help, the diagnostic for std::same_as<T, U> does show the types. But writing std::same_as<std::integral_constant<std::size_t, sizeof(T)>, std::integral_constant<std::size_t, 4>> as the assertion just to get sizeof(T) in the diagnostics is "suboptimal".
