diff --git a/tests/mypy_test.py b/tests/mypy_test.py
index 48ad62e98a2e..4fae05b3bc18 100755
--- a/tests/mypy_test.py
+++ b/tests/mypy_test.py
@@ -135,6 +135,7 @@ def main():
             flags.append('--show-traceback')
             flags.append('--no-implicit-optional')
             flags.append('--disallow-any-generics')
+            flags.append('--disallow-subclassing-any')
             if args.warn_unused_ignores:
                 flags.append('--warn-unused-ignores')
             if args.platform:
diff --git a/third_party/2/fb303/FacebookService.pyi b/third_party/2/fb303/FacebookService.pyi
index ead5d24fe7a3..763c3c83aa1e 100644
--- a/third_party/2/fb303/FacebookService.pyi
+++ b/third_party/2/fb303/FacebookService.pyi
@@ -58,7 +58,7 @@ class Client(Iface):
     def shutdown(self): ...
     def send_shutdown(self): ...
 
-class Processor(Iface, TProcessor):
+class Processor(Iface, TProcessor):  # type: ignore
     def __init__(self, handler) -> None: ...
     def process(self, iprot, oprot): ...
     def process_getName(self, seqid, iprot, oprot): ...
diff --git a/third_party/2/scribe/scribe.pyi b/third_party/2/scribe/scribe.pyi
index 3530bf80a809..c170447e14c8 100644
--- a/third_party/2/scribe/scribe.pyi
+++ b/third_party/2/scribe/scribe.pyi
@@ -13,7 +13,7 @@ class Client(fb303.FacebookService.Client, Iface):
     def send_Log(self, messages): ...
     def recv_Log(self): ...
 
-class Processor(fb303.FacebookService.Processor, Iface, TProcessor):
+class Processor(fb303.FacebookService.Processor, Iface, TProcessor):  # type: ignore
     def __init__(self, handler) -> None: ...
     def process(self, iprot, oprot): ...
     def process_Log(self, seqid, iprot, oprot): ...
diff --git a/third_party/2and3/google/protobuf/internal/containers.pyi b/third_party/2and3/google/protobuf/internal/containers.pyi
index fc97c7330ce3..2b0a5f1e196a 100644
--- a/third_party/2and3/google/protobuf/internal/containers.pyi
+++ b/third_party/2and3/google/protobuf/internal/containers.pyi
@@ -50,7 +50,8 @@ class RepeatedCompositeFieldContainer(BaseContainer[_T]):
     def __eq__(self, other: object) -> bool: ...
 
 # Classes not yet typed
-class Mapping(Any): ...
+class Mapping(object):
+    def __getattr__(self, name: str) -> Any: ...  # incomplete
 class MutableMapping(Mapping): ...
 class ScalarMap(MutableMapping): ...
 class MessageMap(MutableMapping): ...