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

[iamsupermouse at mail dot ru via Gcc-bugs]

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

--- Comment #1 from Egor <iamsupermouse at mail dot ru> ---
I was told this is a wording defect. The `cpp17-forward-iterator`
exposition-only concept in https://eel.is/c++draft/iterator.traits only permits
lvalue references.