[Bug libstdc++/106676] [C++20] Automatic iterator_category detection misbehaves when `::reference` is an rvalue reference, refuses to accept a forward iterator

[avi at scylladb dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106676

--- Comment #13 from Avi Kivity <avi at scylladb dot com> ---
Yes, thanks. The initial sin was mixing the two almost-the-same-but-not-quite
frameworks by using std::istream_iterator to source an input_iterator. I see I
should have used std::ranges::istream_view to keep everything consistent.