Does this crate alias mutable references?

[Kestrer]

I'm pretty sure this crate ends up aliasing mutable references, as each future, when polled, holds a mutable reference to the data at the same time as the linked list does.

As an example: suppose there is a ManualResetEvent, and this happens:

• .wait() is called, and the future is polled once. This will insert a raw pointer to its WaitQueueEntry inside the ManualResetEvent's linked list.
• At this point, we have a mutable reference to the WaitQueueEntry transitively through the future.
• .set() is called. This then calls LinkedList::reverse_drain, which creates a &mut ListNode<WaitQueueEntry> that aliases with the one held by the future. This is UB.

However I couldn't get Miri to trigger on this, so I'm not sure.

[goffrie]

I believe this is true, but I also don't think it's possible to resolve this without something like AliasedCell from rust-lang/rust#63818, because Future::poll receives a Pin<&mut Self> argument and therefore always borrows the entire thing, even if we don't want to.

IIRC a number of tests in this crate fail under miri because of this.