Re: [PATCH] Warn when comparing nonnull arguments to NULL in a function.

[Martin Sebor <msebor@gmail.com>]

> +void foo(void *bar) __attribute__((nonnull(1)));
> +
> +void foo(void *bar) { if (!bar) abort(); } /* { dg-warning "null" "argument ‘bar’ compared to NULL" } */

This looks like a very useful enhancement. Since the change is limited
to build_binary_op in the two front ends I wonder if the warning also
issued for other expressions? For example, suppose I were to add to
function foo above the following:

      bool is_null = bar;

would GCC issue a warning? The same question goes for other expressions
non-binary expressions, including:

      bar ? f () : g ();

or in C++:

      bool x = static_cast<bool>(bar);

If not, I would think issuing it would make the feature even more
useful (and the diagnostics more consistent).

Martin