Fix mypy issues

changes/1192.bugfix.md

@@ -1,2 +1,2 @@
 Properly garbage collect message references in the cache
- - properly deserialize `PartialMessage.referenced_message` as the partial message it is
+ - Properly deserialize `PartialMessage.referenced_message` as a partial message

hikari/impl/cache.py

@@ -1564,15 +1564,11 @@ def _set_message(
  referenced_message: typing.Optional[cache_utility.RefCell[cache_utility.MessageData]] = None
  if message.referenced_message:
  reference_id = message.referenced_message.id
+ referenced_message = self._message_entries.get(reference_id) or self._referenced_messages.get(reference_id)
 
- if referenced_message := (
- self._message_entries.get(reference_id) or self._referenced_messages.get(reference_id)
- ):
- # We just update the already cached message to prevent losing the link between referenced messages,
- # which could lead to a memory leak when garbage collecting
+ if referenced_message:
+ # Since the message is partial, if we don't have it cached, there is nothing we can do about it
  referenced_message.object.update(message.referenced_message)
- else:
- referenced_message = self._set_message(message.referenced_message)
 
  # Only increment ref counts if this wasn't previously cached.
  if message.id not in self._referenced_messages and message.id not in self._message_entries:

hikari/internal/cache.py

@@ -723,9 +723,6 @@ def build_from_entity(
  if not member and message.member:
  member = RefCell(MemberData.build_from_entity(message.member))
 
- if not referenced_message and message.referenced_message:
- referenced_message = RefCell(MessageData.build_from_entity(message.referenced_message))
-
  interaction = (
  MessageInteractionData.build_from_entity(message.interaction, user=interaction_user)
  if message.interaction