// Copyright 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. // pretty-expanded FIXME #23616 #![allow(unknown_features)] #![feature(box_syntax, io)] use std::io::{self, Write}; fn f(wr: &mut Write) { wr.write_all(b"hello").ok().expect("failed"); } fn main() { let mut wr = box io::stdout() as Box; f(&mut wr); }