// Copyright 2013-2014 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 or the MIT license // , at your // option. This file may not be copied, modified, or distributed // except according to those terms. // Testing guarantees provided by once functions. #[feature(once_fns)]; extern crate sync; use sync::Arc; fn foo(blk: proc()) { blk(); } pub fn main() { let x = Arc::new(true); foo(proc() { assert!(*x); drop(x); }); }