rust/src/test/run-pass/writealias.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.

use std::sync::Mutex;

struct Point {x: int, y: int, z: int}

fn f(p: &mut Point) { p.z = 13; }

pub fn main() {
    unsafe {
        let x = Some(Mutex::new(true));
        match x {
            Some(ref z) if *z.lock() => {
                assert!(*z.lock());
            },
            _ => panic!()
        }
    }
}