1use futures::executor::block_on;
2use futures::future::Future;
3use std::task::Poll;
4
5/// This tests verifies (through miri) that self-referencing
6/// futures are not invalidated when joining them.
7#[test]
8fn futures_join_macro_self_referential() {
9 block_on(async { futures::join!(yield_now(), trouble()) });
10}
11
12async fn trouble() {
13 let lucky_number = 42;
14 let problematic_variable = &lucky_number;
15
16 yield_now().await;
17
18 // problematic dereference
19 let _ = { *problematic_variable };
20}
21
22fn yield_now() -> impl Future<Output = ()> {
23 let mut yielded = false;
24 std::future::poll_fn(move |cx| {
25 if core::mem::replace(&mut yielded, true) {
26 Poll::Ready(())
27 } else {
28 cx.waker().wake_by_ref();
29 Poll::Pending
30 }
31 })
32}
33