[ REQ 6895]: On using -Wall in GCC

[rms at gnu.org]

I'd like to remind all GNU developers that the GNU Project
does not urge or recommend using the GCC -Wall option.

When I implemented the -Wall option, I implemented every warning that
anyone asked for (if it was possible).  I implemented warnings that
seemed useful, and warnings that seemed silly, deliberately without
judging them, to produce a feature which is at the upper limit of
strictness.

If you want such strict criteria for your programs, then -Wall is for
you.  But changing code to avoid them is a lot of work.  If you don't
feel inclined to do that work, please don't let anyone else pressure
you into using -Wall.  If people say they would like to use it, you
don't have to listen.  They're asking you to do a lot of work.
If you don't feel it is useful, you don't have to do it.

I never use -Wall myself.