@@ -1,4 +1,4 @@
-from asyncio import Event, ensure_future, Future, wait
+from asyncio import Event, ensure_future, Future, wait, CancelledError
 from concurrent.futures import FIRST_COMPLETED
 from inspect import isasyncgen, isawaitable
 from typing import cast, Any, AsyncIterable, Callable, Optional, Set, Type, Union
@@ -43,9 +43,20 @@ async def __anext__(self) -> Any:
 aclose = ensure_future(self._close_event.wait())
 anext = ensure_future(self.iterator.__anext__())
 
-pending: Set[Future] = (
-await wait([aclose, anext], return_when=FIRST_COMPLETED)
-)[1]
+# Suppress the StopAsyncIteration exception warning when the
+# iterator is cancelled.
+anext.add_done_callback(lambda *args: anext.exception())
+try:
+pending: Set[Future] = (
+await wait([aclose, anext], return_when=FIRST_COMPLETED)
+)[1]
+except CancelledError as e:
+# The iterator is cancelled
+aclose.cancel()
+anext.cancel()
+self.is_closed = True
+raise StopAsyncIteration from e
+
 for task in pending:
 task.cancel()
 

@@ -1,5 +1,5 @@
 import sys
-from asyncio import Event, ensure_future, sleep
+from asyncio import Event, ensure_future, CancelledError, sleep, Queue
 
 from pytest import mark, raises # type: ignore
 
@@ -457,3 +457,41 @@ async def aclose(self):
 await anext(doubles)
 assert not doubles.is_closed
 assert not iterator.is_closed
+
+@mark.asyncio
+async def cancel_async_iterator_while_waiting():
+class Iterator:
+def __init__(self):
+self.queue: Queue[int] = Queue()
+self.queue.put_nowait(1) # suppress coverage warning
+self.cancelled = False
+
+def __aiter__(self):
+return self
+
+async def __anext__(self):
+try:
+return await self.queue.get()
+except BaseException:
+self.cancelled = True
+
+iterator = Iterator()
+doubles = MapAsyncIterator(iterator, lambda x: x + x)
+
+async def iterator_task():
+try:
+async for double in doubles:
+pass
+# If cancellation is handled using StopAsyncIteration, it will reach
+# here.
+except CancelledError: # pragma: no cover
+# Otherwise it should reach here
+pass
+
+task = ensure_future(iterator_task())
+await sleep(0.1)
+await doubles.aclose()
+task.cancel()
+await sleep(0.1)
+assert iterator.cancelled
+assert doubles.is_closed