[Bug c/81453] relational expression involving null pointer not diagnosed with -Wall

[msebor at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81453

Martin Sebor <msebor at gcc dot gnu.org> changed:

           What    |Removed                     |Added
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           Keywords|                            |patch

--- Comment #4 from Martin Sebor <msebor at gcc dot gnu.org> ---
I'm not sure pr103945 is a duplicate of this feature request: this one is about
relational expressions involving a null pointer, while pr103945 is about
relational expressions involving function pointers.  Both sets of expressions
are invalid, but both are also quite different.

That said, as I mentioned in bug 103945 comment 4: the patch I submitted in
October 2020 detects invalid relational comparisons of unrelated pointers of
all kinds (https://gcc.gnu.org/pipermail/gcc-patches/2020-November/558775.html;
the patch review was never finished).  I'd expect it to also diagnose
relational expressions involving null pointers (because they're treated as
distinct by the pointer-query infrastructure) but I don't see any tests for it,