Merge pull request #416 from moka-rs/fix-stacked-borrow-violation

Fix Miri error (Stacked Borrow violation) in the test code of the timer wheel

src/common/timer_wheel.rs

@@ -509,16 +509,21 @@ impl<'iter, K> Iterator for TimerEventsIter<'iter, K> {
  node.as_ref().element.unset_timer_node_in_deq_nodes();
  return Some(TimerEvent::Expired(node));
  }
+
  // The cache entry has not expired. Reschedule it.
  let node_p = NonNull::new(Box::into_raw(node)).expect("Got a null ptr");
+
+ #[cfg(test)]
+ // Get the entry info before rescheduling (mutating) the node to
+ // avoid Stacked Borrows/Tree Borrows violations on `node_p`.
+ let entry_info =
+ TrioArc::clone(unsafe { node_p.as_ref() }.element.entry_info());
+
  match self.timer_wheel.schedule_existing_node(node_p) {
- #[cfg(test)]
- ReschedulingResult::Rescheduled => {
- let entry_info = unsafe { node_p.as_ref() }.element.entry_info();
- return Some(TimerEvent::Rescheduled(TrioArc::clone(entry_info)));
- }
- #[cfg(not(test))]
  ReschedulingResult::Rescheduled => {
+ #[cfg(test)]
+ return Some(TimerEvent::Rescheduled(entry_info));
+ #[cfg(not(test))]
  return Some(TimerEvent::Rescheduled(()));
  }
  ReschedulingResult::Removed(node) => {