[Bug libstdc++/106610] elements_view::iterator::iterator_category invokes the operator*() && of the underlying iterator

[redi at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106610

--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Isn't this invalid because of [concepts.equality] p6?

The indirectly_readable concept requires that *it works on a const lvalue,
which means it has to behave the same on lvalues and rvalues or the same type,
const and non-const.