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//@ run-pass
//@ check-run-results
// Future `bar` with internal async drop `Foo` will have async drop itself.
// And we trying to drop this future in sync context (`block_on` func)
#![feature(async_drop)]
#![allow(incomplete_features)]
//@ edition: 2021
use std::{
future::{Future, AsyncDrop},
pin::{pin, Pin},
sync::{mpsc, Arc},
task::{Context, Poll, Wake, Waker},
};
struct Foo {
my_resource_handle: usize,
}
impl Foo {
fn new(my_resource_handle: usize) -> Self {
let out = Foo {
my_resource_handle,
};
println!("Foo::new({})", my_resource_handle);
out
}
}
impl Drop for Foo {
fn drop(&mut self) {
println!("Foo::drop({})", self.my_resource_handle);
}
}
impl AsyncDrop for Foo {
async fn drop(self: Pin<&mut Self>) {
println!("Foo::async drop({})", self.my_resource_handle);
}
}
fn main() {
block_on(bar(10));
println!("done")
}
async fn bar(ident_base: usize) {
let mut _first = Foo::new(ident_base);
}
fn block_on<F>(fut: F) -> F::Output
where
F: Future,
{
let mut fut = pin!(fut);
let (waker, rx) = simple_waker();
let mut context = Context::from_waker(&waker);
loop {
match fut.as_mut().poll(&mut context) {
Poll::Ready(out) => break out,
// expect wake in polls
Poll::Pending => rx.try_recv().unwrap(),
}
}
}
fn simple_waker() -> (Waker, mpsc::Receiver<()>) {
struct SimpleWaker {
tx: std::sync::mpsc::Sender<()>,
}
impl Wake for SimpleWaker {
fn wake(self: Arc<Self>) {
self.tx.send(()).unwrap();
}
}
let (tx, rx) = mpsc::channel();
(Waker::from(Arc::new(SimpleWaker { tx })), rx)
}
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