[Bug libstdc++/68222] _Safe_iterator provides operators the wrapped iterator can't actually support

[TonyELewis at hotmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68222

--- Comment #4 from Tony E Lewis <TonyELewis at hotmail dot com> ---
Yes - Godbolt's GCC trunk is now showing an error where I'd expect within the
original repro code.

Great stuff. Thanks very much for your work on this.