https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102358
--- Comment #4 from Artur Bać <gcc at ebasoft dot com.pl> --- In 12 ? In 11.2.1/include/g++-v11/bits/cpp_type_traits.h template<typename _Iterator> _GLIBCXX20_CONSTEXPR inline _Iterator __miter_base(_Iterator __it) and as it was mentioned overload in stl_iterator.h has missing constexpr at all.