No type checking in ctype builtins

[Jonathan Wakely]

On Wed, 27 Apr 2022 at 16:29, Andrea Monaco via Gcc <gcc@gcc.gnu.org> wrote:
>
>
> This program
>
>   #include <ctype.h>
>
>   int main ()
>   {
>     char *s;
>     isspace (s);
>   }
>
> compiles with no warning in gcc 8.3.0, even though there's a type
> mistake; the correct call would be isspace (*s).

N.B. The correct call would be isspace((unsigned char)*s) because
isspace has undefined behaviour if you pass it a char with a negative
value.

It would be nice if GCC warned about *that*.