[Bug c++/118720] Bug with unsigned ints

[ddgreen at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=118720

--- Comment #7 from Daniel Green <ddgreen at gmail dot com> ---
(In reply to Jonathan Wakely from comment #6)
> std::span should diagnose it with -fhardened

I couldn't get `-fhardened` to complain either on godbolt or locally (with gcc
14.2.0). I tried `-O0`, `-O1`, `-O3`, and also explicitly putting
`-D_FORTIFY_SOURCE=3`, and `-D_FORTIFY_SOURCE=0`. I always got `warning:
‘_FORTIFY_SOURCE’ is not enabled by ‘-fhardened’ because it was specified in
‘-D’ or ‘-U’ [-Whardened]`, but no complaints at compile or runtime about the
code.