#include<stdio.h>
void foo() { }
int main() {
    void a = foo();
    return 0;
}

/*
void-rv-assign.c:4:10: error: variable or field ‘a’ declared void
     void a = foo();
          ^
void-rv-assign.c:4:14: error: void value not ignored as it ought to be
     void a = foo();
              ^~~
*/