[Bug c++/53181] static_assert sees as non constant the comparison between a constexpr and a template argument

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53181

--- Comment #7 from Jonathan Wakely <redi at gcc dot gnu.org> ---
GCC 7 accepts it in C++17 mode because of r241137

    Implement P0386R2 - C++17 inline variables

That's because an out-of-class definition is not needed in C++17, the compiler
will generate one from the in-class declaration.