1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
|
// run-pass
// Checks that the Fn trait hierarchy rules permit
// any Fn trait to be used where Fn is implemented.
#![feature(unboxed_closures, fn_traits)]
use std::ops::{Fn,FnMut,FnOnce};
struct S;
impl Fn<(i32,)> for S {
extern "rust-call" fn call(&self, (x,): (i32,)) -> i32 {
x * x
}
}
impl FnMut<(i32,)> for S {
extern "rust-call" fn call_mut(&mut self, args: (i32,)) -> i32 { self.call(args) }
}
impl FnOnce<(i32,)> for S {
type Output = i32;
extern "rust-call" fn call_once(self, args: (i32,)) -> i32 { self.call(args) }
}
fn call_it<F:Fn(i32)->i32>(f: &F, x: i32) -> i32 {
f(x)
}
fn call_it_mut<F:FnMut(i32)->i32>(f: &mut F, x: i32) -> i32 {
f(x)
}
fn call_it_once<F:FnOnce(i32)->i32>(f: F, x: i32) -> i32 {
f(x)
}
fn main() {
let x = call_it(&S, 22);
let y = call_it_mut(&mut S, 22);
let z = call_it_once(S, 22);
assert_eq!(x, y);
assert_eq!(y, z);
}
|
