rust/src/test/run-pass/issue-980.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.

enum maybe_pointy {
    no_pointy,
    yes_pointy(@mut Pointy),
}

struct Pointy {
    x : maybe_pointy
}

pub fn main() {
    let m = @mut Pointy { x : no_pointy };
    m.x = yes_pointy(m);
}