// 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(unboxed_closures)] fn with_int(f: &mut FnMut(&isize)) { } fn main() { let mut x: Option<&isize> = None; with_int(&mut |y| x = Some(y)); //~ ERROR cannot infer }