1 // run-pass
2 // Checks that the Fn trait hierarchy rules permit
3 // any Fn trait to be used where Fn is implemented.
4
5 #![feature(unboxed_closures, fn_traits)]
6
7 use std::ops::{Fn,FnMut,FnOnce};
8
9 struct S;
10
11 impl Fn<(i32,)> for S {
call(&self, (x,): (i32,)) -> i3212 extern "rust-call" fn call(&self, (x,): (i32,)) -> i32 {
13 x * x
14 }
15 }
16
17 impl FnMut<(i32,)> for S {
call_mut(&mut self, args: (i32,)) -> i3218 extern "rust-call" fn call_mut(&mut self, args: (i32,)) -> i32 { self.call(args) }
19 }
20
21 impl FnOnce<(i32,)> for S {
22 type Output = i32;
call_once(self, args: (i32,)) -> i3223 extern "rust-call" fn call_once(self, args: (i32,)) -> i32 { self.call(args) }
24 }
25
call_it<F:Fn(i32)->i32>(f: &F, x: i32) -> i3226 fn call_it<F:Fn(i32)->i32>(f: &F, x: i32) -> i32 {
27 f(x)
28 }
29
call_it_mut<F:FnMut(i32)->i32>(f: &mut F, x: i32) -> i3230 fn call_it_mut<F:FnMut(i32)->i32>(f: &mut F, x: i32) -> i32 {
31 f(x)
32 }
33
call_it_once<F:FnOnce(i32)->i32>(f: F, x: i32) -> i3234 fn call_it_once<F:FnOnce(i32)->i32>(f: F, x: i32) -> i32 {
35 f(x)
36 }
37
main()38 fn main() {
39 let x = call_it(&S, 22);
40 let y = call_it_mut(&mut S, 22);
41 let z = call_it_once(S, 22);
42 assert_eq!(x, y);
43 assert_eq!(y, z);
44 }
45