[PATCH] Add a warning for invalid function casts

[Joseph Myers]

On Thu, 12 Oct 2017, Martin Sebor wrote:

> Yes.  In light of this discussion I am thinking it might be
> worthwhile to bring up the issue of generic function pointers
> with WG14 for C2X.

I'm fine with the idea of having a standard solution that (unlike void (*) 
(void)) cannot be called at all without converting to another type.  I 
just maintain that void (*) (void) is the de facto idiom for this and so 
the warning should reflect this even in the future presence of such a 
standard solution (much as we e.g. handle trailing [1] arrays in structs 
as possibly being used as flexible array members in code using that as a 
C89/C++-compatible idiom rather than relying on C99 flexible array 
members).

-- 
Joseph S. Myers
joseph@codesourcery.com