rust/src/test/run-pass/option-unwrap.rs
2012-12-10 17:32:58 -08:00

40 lines
892 B
Rust

// 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.
struct dtor {
x: @mut int,
}
impl dtor : Drop {
fn finalize(&self) {
// abuse access to shared mutable state to write this code
*self.x -= 1;
}
}
fn unwrap<T>(+o: Option<T>) -> T {
match move o {
Some(move v) => move v,
None => fail
}
}
fn main() {
let x = @mut 1;
{
let b = Some(dtor { x:x });
let c = unwrap(move b);
}
assert *x == 0;
}