[Bug c/71157] -Wnull-dereference false alarm in wrong function

[eggert at gnu dot org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71157

--- Comment #9 from Paul Eggert <eggert at gnu dot org> ---
(In reply to Eric Gallager from comment #8)

> Try marking it up with __attribute__((returns_nonnull)) and/or
> __attribute__((nonnull)). If the first one works, then it's a case where GCC
> should suggest it, in which case it's bug 84203.

Neither suggestion works, unfortunately. That is, I tried undoing the
abovementioned patch to etags.c that works around the problem, and then
modifying the declaration of skip_spaces this way:

static char *skip_spaces (char *) __attribute__ ((nonnull (1)));

or this way:

static char *skip_spaces (char *) __attribute__ ((returns_nonnull));

Neither modification worked: in both cases I still got the bogus warnings. This
was with gcc (Ubuntu 7.3.0-16ubuntu3) 7.3.0.