https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115209
--- Comment #4 from 康桓瑋 <hewillk at gmail dot com> --- > Our concat_view implementation is accidentally based off of an older > revision of the paper, P2542R7 instead of R8. As far as I can tell the > only semantic change in the final revision is the relaxed constraints on > the iterator's iter/sent operator- overloads, which this patch updates. But the end() does not have the std::semiregular constraint so far as I can tell.
