extern crate futures;
extern crate tokio;

use futures::{Future, Async};

#[derive(Clone)]
pub struct HoldMe{}

impl Drop for HoldMe{
    fn drop(&mut self) {
        panic!("HoldMe is dropped");
    }
}

struct Never{}
impl Future for Never{
    type Item  = ();
    type Error = ();
    fn poll (&mut self) -> Result<Async<()>, ()> {
        Ok(Async::NotReady)
    }
}

pub fn main() {
    tokio::run(futures::lazy(move || {
        let hold = HoldMe{};
        Never{}
        .map(move |_|{
            println!("dropping now");
            drop(hold);
        })
    }));
}