[Bug libstdc++/106013] weakly_incrementable cannot apply on common_iterator

[hewillk at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106013

--- Comment #1 from 康桓瑋 <hewillk at gmail dot com> ---
Note that if I add using value_type = int it will compile fine.