https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107861
--- Comment #8 from Jonathan Wakely <redi at gcc dot gnu.org> --- (In reply to Jonathan Wakely from comment #7) > int_max+1 is not a core constant (C++20 7.7 [expr.const] paragraph 5, bullet oops, s/core constant/core constant expression/ > 5.7), so is not usable as the condition in a static_assert, so the program > is ill-formed.