rust/src/test/compile-fail/borrowck-loan-blocks-mut-uniq.rs

// 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 <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(box_syntax)]

fn borrow<F>(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() {
}