https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104465
--- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> --- (In reply to Younan Zhang from comment #0) > cppreference (https://en.cppreference.com/w/cpp/ranges/reverse_view) or > C++20 draft suggests (24.7.1 [range.adaptor.object]/1, > https://timsong-cpp.github.io/cppwp/n4861/range.adaptors#range.adaptor. > object-1), the range adaptor `std::views::reverse` only takes > `viewable_range` as arguments. So it makes me confused and I wonder if I > missed something. [range.adaptor.object] says what happens if you use a viewable_range argument, but it doesn't say what happens if you use something else. Specifically, it doesn't say it's ill-formed.
