cramertj.rs

// This program:

#![feature(conservative_impl_trait)]

use std::fmt::Debug;

#[derive(Debug)]
struct Foo<'a> { x: &'a i32 }

unsafe impl Send for Foo<'static> { }

fn foo<'a>(x: &'a i32) -> impl Debug + 'a {
    Foo { x }
}

fn bar() {
    let mut x = 5;
    x += 5;
    let y = || foo(&x);
    is_send(y());
}

fn is_send<T: Send>(_t: T) { }

fn main() {}