[Bug libstdc++/106803] New: views::adjacent_transform should not return views::empty> when N == 0

[hewillk at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106803

            Bug ID: 106803
           Summary: views::adjacent_transform should not return
                    views::empty<tuple<>> when N == 0
           Product: gcc
           Version: 13.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libstdc++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: hewillk at gmail dot com
  Target Milestone: ---

views::adjacent_transform seems to incorrectly copy-paste views::adjacent's
operator(), which makes it return views​::​empty<tuple<>> when N == 0, however,
according to the standard, it should return views​::​zip_transform(F) which is
views::empty<decay_t<invoke_result_t<FD&>>>.