Incompatible function pointer calls

[mchalupa]

In the following program, slicer generates an empty main (w.r.t assertion):

#include <assert.h>                                                                          
                                                                                   
int foo(void) {                                                                 
    assert(0);                                                                  
}                                                                               
                                                                                
int main() {                                                                    
    void (*f)() = foo;                                                          
    f();                                                                        
}                                                                               

The problem is that foo is not identified as a possible call target, because the declaration is not compatible with the function pointer. It is, in fact, undefined behavior. From C99 standard:

[UB is when] a pointer is used to call a function whose type is not compatible with the pointed-to type (6.3.2.3).

However, in real programs, such calls can be found, so maybe we could relax our default policy about compatibility of function pointers.