[Bug c/16351] NULL dereference warnings

[jg at jguk dot org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=16351

--- Comment #49 from Jon Grant <jg at jguk dot org> ---
(In reply to Martin Sebor from comment #48)
> Send a check to Manuel ;)  The feature is available under the
> -Wnull-dereference option (see comment 31).  Unfortunately, due to false
> positives, the option was removed from -Wall in a subsequent commit
> (r226751) and has to be enabled explicitly.
> 
> The similar -Wnonnull option that was just recently enhanced to detect
> related problems is in -Wall, and it seems to me that it would make sense to
> treat both of these options the same: i.e., enable both with -Wall.  To do
> that, the former option might need to be tweaked to reduce its false
> positive rate.  At the same time, the -Wnonnull option still has a high rate
> of false negatives and so it could stand to be enhanced to do a better job. 
> The challenge is striking the right balance between the two rates that is
> acceptable to everyone.

Thank you for your reply.

-Werror=null-dereference doesn't seem to be in my compiler:
gcc (Ubuntu 5.4.0-6ubuntu1~16.04.4) 5.4.0 20160609

Is it just in GCC6 branch?

-Wnonnull  is present though.


Re the feature, I think it can't be that hard to check per function can it...?