| // 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. |
| |
| #![feature(conservative_impl_trait)] |
| |
| // Fast path, main can see the concrete type returned. |
| fn before() -> impl FnMut(i32) { |
| let mut p = Box::new(0); |
| move |x| *p = x |
| } |
| |
| fn send<T: Send>(_: T) {} |
| |
| fn main() { |
| send(before()); |
| send(after()); |
| } |
| |
| // Deferred path, main has to wait until typeck finishes, |
| // to check if the return type of after is Send. |
| fn after() -> impl FnMut(i32) { |
| let mut p = Box::new(0); |
| move |x| *p = x |
| } |
