[Bug c++/101029] unexpected error: non-constant condition for static assertion in gcc 10/11, but not 9 (clang also fine)

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101029

--- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> ---
(In reply to Jim Walker from comment #0)
> /opt/gcc-10.2.0/include/c++/10.2.0/type_traits:918:52: error: non-constant
> condition for static assertion
>   918 |      
> static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),

This assertion was added for gcc 10, which is why you don't see it with gcc 9.