| // Copyright 2014 The Rust Project Developers. See the COPYRIGHT |
| // file at the top-level directory of this distribution and at |
| // http://rust-lang.org/COPYRIGHT. |
| // |
| // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or |
| // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license |
| // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your |
| // option. This file may not be copied, modified, or distributed |
| // except according to those terms. |
| |
| // Checks that the Fn trait hierarchy rules permit |
| // FnMut or FnOnce to be used where FnMut is implemented. |
| |
| #![feature(unboxed_closures, fn_traits)] |
| |
| struct S; |
| |
| impl FnMut<(i32,)> for S { |
| extern "rust-call" fn call_mut(&mut self, (x,): (i32,)) -> i32 { |
| x * x |
| } |
| } |
| |
| impl FnOnce<(i32,)> for S { |
| type Output = i32; |
| |
| extern "rust-call" fn call_once(mut self, args: (i32,)) -> i32 { self.call_mut(args) } |
| } |
| |
| 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 y = call_it_mut(&mut S, 22); |
| let z = call_it_once(S, 22); |
| assert_eq!(y, z); |
| } |