[Bug c/125524] warning for __counted_by(len) field (or sanitizer) being changed not atomically

[cagney at sourceware dot org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=125524

--- Comment #5 from cagney at sourceware dot org ---
> Basically:
> buf->ptr++;
> Is ignored.

Silent and deadly.

The lack of even a warning means that legacy code can't trust this new feature.