Remove redundant types from comments. (#14412)

Remove type hints from comments which have been added
as Python type hints. This helps avoid drift between comments
and reality, as well as removing redundant information.

Also adds some missing type hints which were simple to fill in.

9 files changed, 18 insertions, 16 deletions

diff --git a/synapse/util/async_helpers.py b/synapse/util/async_helpers.py
index 7f1d41eb3c..d24c4f68c4 100644
--- a/synapse/util/async_helpers.py
+++ b/synapse/util/async_helpers.py
@@ -217,7 +217,8 @@ async def concurrently_execute(
         limit: Maximum number of conccurent executions.
 
     Returns:
-        Deferred: Resolved when all function invocations have finished.
+        None, when all function invocations have finished. The return values
+        from those functions are discarded.
     """
     it = iter(args)
 
diff --git a/synapse/util/caches/__init__.py b/synapse/util/caches/__init__.py
index f7c3a6794e..9387632d0d 100644
--- a/synapse/util/caches/__init__.py
+++ b/synapse/util/caches/__init__.py
@@ -197,7 +197,7 @@ def register_cache(
         resize_callback: A function which can be called to resize the cache.
 
     Returns:
-        CacheMetric: an object which provides inc_{hits,misses,evictions} methods
+        an object which provides inc_{hits,misses,evictions} methods
     """
     if resizable:
         if not resize_callback:
diff --git a/synapse/util/caches/deferred_cache.py b/synapse/util/caches/deferred_cache.py
index bcb1cba362..bf7bd351e0 100644
--- a/synapse/util/caches/deferred_cache.py
+++ b/synapse/util/caches/deferred_cache.py
@@ -153,7 +153,7 @@ class DeferredCache(Generic[KT, VT]):
         Args:
             key:
             callback: Gets called when the entry in the cache is invalidated
-            update_metrics (bool): whether to update the cache hit rate metrics
+            update_metrics: whether to update the cache hit rate metrics
 
         Returns:
             A Deferred which completes with the result. Note that this may later fail
diff --git a/synapse/util/caches/dictionary_cache.py b/synapse/util/caches/dictionary_cache.py
index fa91479c97..5eaf70c7ab 100644
--- a/synapse/util/caches/dictionary_cache.py
+++ b/synapse/util/caches/dictionary_cache.py
@@ -169,10 +169,11 @@ class DictionaryCache(Generic[KT, DKT, DV]):
                 if it is in the cache.
 
         Returns:
-            DictionaryEntry: If `dict_keys` is not None then `DictionaryEntry`
-            will contain include the keys that are in the cache. If None then
-            will either return the full dict if in the cache, or the empty
-            dict (with `full` set to False) if it isn't.
+            If `dict_keys` is not None then `DictionaryEntry` will contain include
+            the keys that are in the cache.
+
+            If None then will either return the full dict if in the cache, or the
+            empty dict (with `full` set to False) if it isn't.
         """
         if dict_keys is None:
             # The caller wants the full set of dictionary keys for this cache key
diff --git a/synapse/util/caches/expiringcache.py b/synapse/util/caches/expiringcache.py
index c6a5d0dfc0..01ad02af67 100644
--- a/synapse/util/caches/expiringcache.py
+++ b/synapse/util/caches/expiringcache.py
@@ -207,7 +207,7 @@ class ExpiringCache(Generic[KT, VT]):
         items from the cache.
 
         Returns:
-            bool: Whether the cache changed size or not.
+            Whether the cache changed size or not.
         """
         new_size = int(self._original_max_size * factor)
         if new_size != self._max_size:
diff --git a/synapse/util/caches/lrucache.py b/synapse/util/caches/lrucache.py
index aa93109d13..dcf0eac3bf 100644
--- a/synapse/util/caches/lrucache.py
+++ b/synapse/util/caches/lrucache.py
@@ -389,11 +389,11 @@ class LruCache(Generic[KT, VT]):
             cache_name: The name of this cache, for the prometheus metrics. If unset,
                 no metrics will be reported on this cache.
 
-            cache_type (type):
+            cache_type:
                 type of underlying cache to be used. Typically one of dict
                 or TreeCache.
 
-            size_callback (func(V) -> int | None):
+            size_callback:
 
             metrics_collection_callback:
                 metrics collection callback. This is called early in the metrics
@@ -403,7 +403,7 @@ class LruCache(Generic[KT, VT]):
 
                 Ignored if cache_name is None.
 
-            apply_cache_factor_from_config (bool): If true, `max_size` will be
+            apply_cache_factor_from_config: If true, `max_size` will be
                 multiplied by a cache factor derived from the homeserver config
 
             clock:
@@ -796,7 +796,7 @@ class LruCache(Generic[KT, VT]):
         items from the cache.
 
         Returns:
-            bool: Whether the cache changed size or not.
+            Whether the cache changed size or not.
         """
         if not self.apply_cache_factor_from_config:
             return False
diff --git a/synapse/util/ratelimitutils.py b/synapse/util/ratelimitutils.py
index 9f64fed0d7..2aceb1a47f 100644
--- a/synapse/util/ratelimitutils.py
+++ b/synapse/util/ratelimitutils.py
@@ -183,7 +183,7 @@ class FederationRateLimiter:
                 # Handle request ...
 
         Args:
-            host (str): Origin of incoming request.
+            host: Origin of incoming request.
 
         Returns:
             context manager which returns a deferred.
diff --git a/synapse/util/threepids.py b/synapse/util/threepids.py
index 1e9c2faa64..54bc7589fd 100644
--- a/synapse/util/threepids.py
+++ b/synapse/util/threepids.py
@@ -48,7 +48,7 @@ async def check_3pid_allowed(
         registration: whether we want to bind the 3PID as part of registering a new user.
 
     Returns:
-        bool: whether the 3PID medium/address is allowed to be added to this HS
+        whether the 3PID medium/address is allowed to be added to this HS
     """
     if not await hs.get_password_auth_provider().is_3pid_allowed(
         medium, address, registration
diff --git a/synapse/util/wheel_timer.py b/synapse/util/wheel_timer.py
index 177e198e7e..b1ec7f4bd8 100644
--- a/synapse/util/wheel_timer.py
+++ b/synapse/util/wheel_timer.py
@@ -90,10 +90,10 @@ class WheelTimer(Generic[T]):
         """Fetch any objects that have timed out
 
         Args:
-            now (ms): Current time in msec
+            now: Current time in msec
 
         Returns:
-            list: List of objects that have timed out
+            List of objects that have timed out
         """
         now_key = int(now / self.bucket_size)