rust/src/test/run-pass/borrowck-preserve-box-in-pat.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.

// exec-env:RUST_POISON_ON_FREE=1

struct F { f: ~int }

fn main() {
    let mut x = @mut @F {f: ~3};
    match x {
      @@F{f: ref b_x} => {
        assert **b_x == 3;
        assert ptr::addr_of(&(x.f)) == ptr::addr_of(b_x);

        *x = @F {f: ~4};

        debug!("ptr::addr_of(*b_x) = %x", ptr::addr_of(&(**b_x)) as uint);
        assert **b_x == 3;
        assert ptr::addr_of(&(*x.f)) != ptr::addr_of(&(**b_x));
      }
    }
}