rust/src/test/compile-fail/once-fn-subtyping.rs

// Copyright 2012-2013 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.

#[feature(once_fns)];
fn main() {
    let f: once || = ||();
    let g: || = f;  //~ ERROR mismatched types
    let h: || = ||();
    let i: once || = h;  // ok
}