// 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. #![feature(box_syntax)] fn borrow(v: &isize, f: F) where F: FnOnce(&isize) { f(v); } fn box_imm() { let mut v = box 3; borrow(&*v, |w| { //~ ERROR cannot borrow `v` as mutable v = box 4; assert_eq!(*v, 3); assert_eq!(*w, 4); }) } fn main() { }