diff --git a/third_party/3/aiofiles/base.pyi b/third_party/3/aiofiles/base.pyi
index 17ac384e8945..13c76ed7e7e1 100644
--- a/third_party/3/aiofiles/base.pyi
+++ b/third_party/3/aiofiles/base.pyi
@@ -1,17 +1,18 @@
 from types import CodeType, FrameType, TracebackType, coroutine
 from typing import Any, Coroutine, Generator, Generic, Iterator, Optional, Type, TypeVar, Union
 
+_T = TypeVar("_T")
 _T_co = TypeVar("_T_co", covariant=True)
 _V_co = TypeVar("_V_co", covariant=True)
 _T_contra = TypeVar("_T_contra", contravariant=True)
 
-class AsyncBase:
+class AsyncBase(Generic[_T]):
     def __init__(self, file: str, loop: Any, executor: Any) -> None: ...
-    async def __aiter__(self) -> Iterator[str]: ...
-    async def __anext__(self) -> str: ...
+    async def __aiter__(self) -> Iterator[_T]: ...
+    async def __anext__(self) -> _T: ...
 
-class AiofilesContextManager(Generic[_V_co, _T_co, _T_contra]):
-    def __init__(self, __coro: Coroutine[_V_co, _T_co, _T_contra]) -> None: ...
+class AiofilesContextManager(Generic[_T_co, _T_contra, _V_co]):
+    def __init__(self, __coro: Coroutine[_T_co, _T_contra, _V_co]) -> None: ...
     def send(self, __value: _T_contra) -> _T_co: ...
     def throw(
         self, __typ: Type[BaseException], __val: Union[BaseException, object] = ..., tb: Optional[TracebackType] = ...
@@ -25,10 +26,10 @@ class AiofilesContextManager(Generic[_V_co, _T_co, _T_contra]):
     def gi_code(self) -> CodeType: ...
     def __next__(self) -> _T_co: ...
     @coroutine
-    def __iter__(self) -> Iterator[Coroutine[_V_co, _T_co, _T_contra]]: ...
-    def __await__(self) -> Generator[Any, None, _T_co]: ...
-    async def __anext__(self) -> Coroutine[_V_co, _T_co, _T_contra]: ...
-    async def __aenter__(self) -> Coroutine[_V_co, _T_co, _T_contra]: ...
+    def __iter__(self) -> Iterator[Coroutine[_T_co, _T_contra, _V_co]]: ...
+    def __await__(self) -> Generator[Any, None, _V_co]: ...
+    async def __anext__(self) -> _V_co: ...
+    async def __aenter__(self) -> _V_co: ...
     async def __aexit__(
         self, exc_type: Optional[Type[BaseException]], exc_val: Optional[BaseException], exc_tb: Optional[TracebackType]
     ) -> None: ...
diff --git a/third_party/3/aiofiles/threadpool/__init__.pyi b/third_party/3/aiofiles/threadpool/__init__.pyi
index c4d8eb9d9683..840f9ce48cd2 100644
--- a/third_party/3/aiofiles/threadpool/__init__.pyi
+++ b/third_party/3/aiofiles/threadpool/__init__.pyi
@@ -2,7 +2,7 @@ from _typeshed import AnyPath, OpenBinaryMode, OpenBinaryModeReading, OpenBinary
 from typing import Any, Callable, Optional, Union, overload
 from typing_extensions import Literal
 
-from ..base import AsyncBase
+from ..base import AiofilesContextManager, AsyncBase
 from .binary import AsyncBufferedIOBase, AsyncBufferedReader, AsyncFileIO
 from .text import AsyncTextIOWrapper
 
@@ -21,7 +21,7 @@ def open(
     *,
     loop: Optional[Any] = ...,
     executor: Optional[Any] = ...,
-) -> AsyncTextIOWrapper: ...
+) -> AiofilesContextManager[None, None, AsyncTextIOWrapper]: ...
 @overload
 def open(
     file: _OpenFile,
@@ -35,7 +35,7 @@ def open(
     *,
     loop: Optional[Any] = ...,
     executor: Optional[Any] = ...,
-) -> AsyncFileIO: ...
+) -> AiofilesContextManager[None, None, AsyncFileIO]: ...
 @overload
 def open(
     file: _OpenFile,
@@ -49,7 +49,7 @@ def open(
     *,
     loop: Optional[Any] = ...,
     executor: Optional[Any] = ...,
-) -> AsyncBufferedIOBase: ...
+) -> AiofilesContextManager[None, None, AsyncBufferedIOBase]: ...
 @overload
 def open(
     file: _OpenFile,
@@ -63,7 +63,7 @@ def open(
     *,
     loop: Optional[Any] = ...,
     executor: Optional[Any] = ...,
-) -> AsyncBufferedReader: ...
+) -> AiofilesContextManager[None, None, AsyncBufferedReader]: ...
 @overload
 def open(
     file: _OpenFile,
@@ -77,4 +77,4 @@ def open(
     *,
     loop: Optional[Any] = ...,
     executor: Optional[Any] = ...,
-) -> AsyncBase: ...
+) -> AiofilesContextManager[None, None, AsyncBase[bytes]]: ...
diff --git a/third_party/3/aiofiles/threadpool/binary.pyi b/third_party/3/aiofiles/threadpool/binary.pyi
index 909c9d2eaf05..5c51c064acbf 100644
--- a/third_party/3/aiofiles/threadpool/binary.pyi
+++ b/third_party/3/aiofiles/threadpool/binary.pyi
@@ -1,5 +1,5 @@
 from ..base import AsyncBase
 
-class AsyncBufferedIOBase(AsyncBase): ...
+class AsyncBufferedIOBase(AsyncBase[bytes]): ...
 class AsyncBufferedReader(AsyncBufferedIOBase): ...
-class AsyncFileIO(AsyncBase): ...
+class AsyncFileIO(AsyncBase[bytes]): ...
diff --git a/third_party/3/aiofiles/threadpool/text.pyi b/third_party/3/aiofiles/threadpool/text.pyi
index fcd8f2df8d3e..7662768f34e0 100644
--- a/third_party/3/aiofiles/threadpool/text.pyi
+++ b/third_party/3/aiofiles/threadpool/text.pyi
@@ -1,3 +1,3 @@
 from ..base import AsyncBase
 
-class AsyncTextIOWrapper(AsyncBase): ...
+class AsyncTextIOWrapper(AsyncBase[str]): ...