1 // run-pass
2 // Checks that higher-ranked extern fn pointers implement the full range of Fn traits.
3
square(x: &isize) -> isize4 fn square(x: &isize) -> isize { (*x) * (*x) }
5
call_it<F:Fn(&isize)->isize>(f: &F, x: isize) -> isize6 fn call_it<F:Fn(&isize)->isize>(f: &F, x: isize) -> isize {
7 (*f)(&x)
8 }
9
call_it_boxed(f: &dyn Fn(&isize) -> isize, x: isize) -> isize10 fn call_it_boxed(f: &dyn Fn(&isize) -> isize, x: isize) -> isize {
11 f(&x)
12 }
13
call_it_mut<F:FnMut(&isize)->isize>(f: &mut F, x: isize) -> isize14 fn call_it_mut<F:FnMut(&isize)->isize>(f: &mut F, x: isize) -> isize {
15 (*f)(&x)
16 }
17
call_it_once<F:FnOnce(&isize)->isize>(f: F, x: isize) -> isize18 fn call_it_once<F:FnOnce(&isize)->isize>(f: F, x: isize) -> isize {
19 f(&x)
20 }
21
main()22 fn main() {
23 let x = call_it(&square, 22);
24 let x1 = call_it_boxed(&square, 22);
25 let y = call_it_mut(&mut square, 22);
26 let z = call_it_once(square, 22);
27 assert_eq!(x, square(&22));
28 assert_eq!(x1, square(&22));
29 assert_eq!(y, square(&22));
30 assert_eq!(z, square(&22));
31 }
32