[Bug libstdc++/115098] std::vector::iterator::reference is default-constructible

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115098

--- Comment #5 from Jonathan Wakely <redi at gcc dot gnu.org> ---
I've just created https://cplusplus.github.io/LWG/issue4140 to remove that
useless default constructor from std::bitset.