[Bug libstdc++/79254] [5/6/7 Regression] basic_string::operator= isn't exception safe

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79254

--- Comment #8 from Jonathan Wakely <redi at gcc dot gnu.org> ---
(In reply to Daryl Haresign from comment #6)
> I guess you don't want _M_copy_assign to be public, either.

Nor inline :-)

Avoiding the try-catch like that is an improvement, I'll do that.