// 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 or the MIT license // , at your // option. This file may not be copied, modified, or distributed // except according to those terms. use std::ops::AddAssign; struct Int(i32); impl AddAssign for Int { fn add_assign(&mut self, _: Int) { unimplemented!() } } fn main() { let mut x = Int(1); x //~ error: use of moved value: `x` //~^ value used here after move //~| note: move occurs because `x` has type `Int` += x; //~ value moved here let y = Int(2); //~^use `mut y` here to make mutable y //~ error: cannot borrow immutable local variable `y` as mutable //~| cannot borrow += Int(1); }