// 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 or the MIT license // , at your // option. This file may not be copied, modified, or distributed // except according to those terms. use std::ops::FnMut; fn call_f(mut f: F) { f(); } fn f() { println!("hello"); } fn call_g String>(mut g: G, x: String, y: String) -> String { g(x, y) } fn g(mut x: String, y: String) -> String { x.push_str(&y); x } fn main() { call_f(f); assert_eq!(call_g(g, "foo".to_string(), "bar".to_string()), "foobar"); }