https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100070
--- Comment #5 from Jonathan Wakely <redi at gcc dot gnu.org> --- If there is code that cares, we could always add std::__cpp17_iterator_category for the cases where we really care about the traditional category (or where we're forwarding the result of *i to user code which might care but we can't tell).