https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102280
--- Comment #1 from Joe Loser <joeloser93 at gmail dot com> --- `span` has a range deduction guide, but it is not properly constrained for ranges satisfying `contiguous_iterator` concept only at https://github.com/gcc-mirror/gcc/blob/01b5038718056b024b370b74a874fbd92c5bbab3/libstdc%2B%2B-v3/include/std/span#L412 per 22.7.3.3 in the working draft.
