// Copyright 2012 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 or the MIT license // , at your // option. This file may not be copied, modified, or distributed // except according to those terms. #![allow(unknown_features)] #![feature(box_syntax)] #![feature(unboxed_closures)] use std::ops::FnMut; fn make_adder(x: i32) -> Boxi32+'static> { (box move |y: i32| -> i32 { x + y }) as Boxi32+'static> } pub fn main() { let mut adder = make_adder(3); let z = adder(2); println!("{}", z); assert_eq!(z, 5); }