constexpr bool operator==(const weekday_last& x, const weekday_last& y) noexcept;
template<class charT, class traits> basic_ostream<charT, traits>& operator<<(basic_ostream<charT, traits>& os, const weekday_last& wdl);
return os << format(os.getloc(), STATICALLY-WIDEN<charT>("{}[last]"), wdl.weekday());