3 files changed, 8 insertions, 18 deletions
diff --git a/synapse/handlers/device.py b/synapse/handlers/device.py
index 54293d0b9c..7e76db3e2a 100644
--- a/synapse/handlers/device.py
+++ b/synapse/handlers/device.py
@@ -631,7 +631,7 @@ class DeviceListUpdater:
             max_len=10000,
             expiry_ms=30 * 60 * 1000,
             iterable=True,
-        )
+        )  # type: ExpiringCache[str, Set[str]]
 
         # Attempt to resync out of sync device lists every 30s.
         self._resync_retry_in_progress = False
@@ -760,7 +760,7 @@ class DeviceListUpdater:
         """Given a list of updates for a user figure out if we need to do a full
         resync, or whether we have enough data that we can just apply the delta.
         """
-        seen_updates = self._seen_updates.get(user_id, set())
+        seen_updates = self._seen_updates.get(user_id, set())  # type: Set[str]
 
         extremity = await self.store.get_device_list_last_stream_id_for_remote(user_id)
 
diff --git a/synapse/handlers/e2e_keys.py b/synapse/handlers/e2e_keys.py
index 739653a3fa..92b18378fc 100644
--- a/synapse/handlers/e2e_keys.py
+++ b/synapse/handlers/e2e_keys.py
@@ -38,7 +38,6 @@ from synapse.types import (
 )
 from synapse.util import json_decoder, unwrapFirstError
 from synapse.util.async_helpers import Linearizer
-from synapse.util.caches.expiringcache import ExpiringCache
 from synapse.util.retryutils import NotRetryingDestination
 
 if TYPE_CHECKING:
@@ -1292,17 +1291,6 @@ class SigningKeyEduUpdater:
         # user_id -> list of updates waiting to be handled.
         self._pending_updates = {}  # type: Dict[str, List[Tuple[JsonDict, JsonDict]]]
 
-        # Recently seen stream ids. We don't bother keeping these in the DB,
-        # but they're useful to have them about to reduce the number of spurious
-        # resyncs.
-        self._seen_updates = ExpiringCache(
-            cache_name="signing_key_update_edu",
-            clock=self.clock,
-            max_len=10000,
-            expiry_ms=30 * 60 * 1000,
-            iterable=True,
-        )
-
     async def incoming_signing_key_update(
         self, origin: str, edu_content: JsonDict
     ) -> None:
diff --git a/synapse/handlers/sync.py b/synapse/handlers/sync.py
index 7b356ba7e5..ff11266c67 100644
--- a/synapse/handlers/sync.py
+++ b/synapse/handlers/sync.py
@@ -252,13 +252,13 @@ class SyncHandler:
         self.storage = hs.get_storage()
         self.state_store = self.storage.state
 
-        # ExpiringCache((User, Device)) -> LruCache(state_key => event_id)
+        # ExpiringCache((User, Device)) -> LruCache(user_id => event_id)
         self.lazy_loaded_members_cache = ExpiringCache(
             "lazy_loaded_members_cache",
             self.clock,
             max_len=0,
             expiry_ms=LAZY_LOADED_MEMBERS_CACHE_MAX_AGE,
-        )
+        )  # type: ExpiringCache[Tuple[str, Optional[str]], LruCache[str, str]]
 
     async def wait_for_sync_for_user(
         self,
@@ -733,8 +733,10 @@ class SyncHandler:
 
     def get_lazy_loaded_members_cache(
         self, cache_key: Tuple[str, Optional[str]]
-    ) -> LruCache:
-        cache = self.lazy_loaded_members_cache.get(cache_key)
+    ) -> LruCache[str, str]:
+        cache = self.lazy_loaded_members_cache.get(
+            cache_key
+        )  # type: Optional[LruCache[str, str]]
         if cache is None:
             logger.debug("creating LruCache for %r", cache_key)
             cache = LruCache(LAZY_LOADED_MEMBERS_CACHE_MAX_SIZE)