| // Copyright 2015 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. |
| |
| #![feature(unboxed_closures)] |
| #![feature(fn_traits)] |
| |
| struct Fun<F>(F); |
| |
| impl<F, T> FnOnce<(T,)> for Fun<F> where F: Fn(T) -> T { |
| type Output = T; |
| |
| extern "rust-call" fn call_once(self, (t,): (T,)) -> T { |
| (self.0)(t) |
| } |
| } |
| |
| fn main() { |
| let fun = Fun(|i: isize| i * 2); |
| println!("{}", fun(3)); |
| } |
