Async patch

src/lib.rs

@@ -139,9 +139,9 @@ extern crate alloc;
 use core::{mem::{self, MaybeUninit}, ptr::{self, NonNull}, marker::PhantomData};
 
 #[cfg(not(loom))]
-use core::{cell::UnsafeCell, sync::atomic::{fence, AtomicU8, Ordering::*}};
+use core::{cell::UnsafeCell, hint, sync::atomic::{fence, AtomicU8, Ordering::*}};
 #[cfg(loom)]
-use loom::{cell::UnsafeCell, sync::atomic::{fence, AtomicU8, Ordering::*}};
+use loom::{cell::UnsafeCell, hint, sync::atomic::{fence, AtomicU8, Ordering::*}};
 
 #[cfg(feature = "async")]
 use core::{
@@ -824,6 +824,11 @@ impl<T> core::future::Future for Receiver<T> {
                     // The sender was dropped before sending anything while we prepared to park.
                     // The sender has taken the waker already.
                     Err(DISCONNECTED) => Poll::Ready(Err(RecvError)),
+                    Err(UNPARKING) => {
+                        cx.waker().wake_by_ref();
+                        hint::spin_loop();
+                        Poll::Pending
+                    },
                     _ => unreachable!(),
                 }
             }