https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61166
--- Comment #8 from Jonathan Wakely <redi at gcc dot gnu.org> --- That's correct, and the standard is clear that operator""ms(unsigned long long) is required to return chrono::milliseconds, not some other equivalent duration with a different Rep. So I think the question in comment 4 is valid: why do we bother with these templates at all?
