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

[hewillk at gmail dot com via Gcc-bugs]

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

--- Comment #1 from 康桓瑋 <hewillk at gmail dot com> ---
std::bitset has similar issues:

#include <bitset>

std::bitset<1> bitset;
typename std::bitset<1>::reference bit_ref(bitset, 0); // well-formed in
libstdc++

https://godbolt.org/z/T4qvv8TcG