// 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 or the MIT license // , at your // option. This file may not be copied, modified, or distributed // except according to those terms. #![feature(box_syntax)] fn f(_: &mut isize) {} fn main() { let mut x: Box<_> = box 3; f(x) //~ ERROR mismatched types }