| // Copyright 2016 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. |
| |
| #![crate_type = "lib"] |
| pub trait Future { |
| type Item; |
| type Error; |
| } |
| |
| impl Future for u32 { |
| type Item = (); |
| type Error = Box<()>; |
| } |
| |
| fn foo() -> Box<Future<Item=(), Error=Box<()>>> { |
| Box::new(0u32) |
| } |
| |
| pub fn bar<F, A, B>(_s: F) |
| where F: Fn(A) -> B, |
| { |
| foo(); |
| } |
