rust/src/test/auxiliary/issue2378a.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<T> { just(T), nothing }

impl copy> for maybe<T> for methods<T {
    fn ~[](idx: uint) -> T {
        match self {
          just(t) { t }
          nothing { fail!(); }
        }
    }
}