[Bug libstdc++/122396] Hard error with optional iterator

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=122396

--- Comment #2 from Tomasz Kamiński <tkaminsk at gcc dot gnu.org> ---
Relevant quote:
> begin/end should be constrained on object types, and Mandate complete object 
> types