[Bug c/95057] missing -Wunused-but-set-variable warning on multiple assignments, not all of them used

[vincent-gcc at vinc17 dot net]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95057

--- Comment #2 from Vincent Lefèvre <vincent-gcc at vinc17 dot net> ---
(In reply to Jakub Jelinek from comment #1)
> That is something this warning can't warn about.
> The warning is a simple FE warning that uses two bits, one for whether
> certain decl was used and one whether it was read.  The warning then
> diagnoses those that have the former bit set and not the latter (of course,
> there are some exceptions etc.).

But when the variable is assigned, the "read" bit could be reset.