From bc2f88d6eeb244a16d4955c12a8e0d00a6da1d5e Mon Sep 17 00:00:00 2001
From: Josh Staiger <joshstaiger@gmail.com>
Date: Sat, 4 Nov 2017 13:56:55 -0700
Subject: [PATCH] Make Executor.__enter__ self and return types match (#1711)

Specifically, this solves a problem in code such as:

with ThreadPoolExecutor() as p: ...

Where the p variable would be typed as an abstract `Executor`, rather than the specific `ThreadPoolExecutor` as expected.
---
 stdlib/3/concurrent/futures/_base.pyi | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/stdlib/3/concurrent/futures/_base.pyi b/stdlib/3/concurrent/futures/_base.pyi
index 836756d5d..56b119b37 100644
--- a/stdlib/3/concurrent/futures/_base.pyi
+++ b/stdlib/3/concurrent/futures/_base.pyi
@@ -35,7 +35,7 @@ class Executor:
     def submit(self, fn: Callable[..., _T], *args: Any, **kwargs: Any) -> Future[_T]: ...
     def map(self, func: Callable[..., _T], *iterables: Iterable[Any], timeout: Optional[float] = ..., chunksize: int = ...) -> Iterator[_T]: ...
     def shutdown(self, wait: bool = ...) -> None: ...
-    def __enter__(self) -> Executor: ...
+    def __enter__(self: _T) -> _T: ...
     def __exit__(self, exc_type: Any, exc_val: Any, exc_tb: Any) -> bool: ...
 
 def as_completed(fs: Iterable[Future[_T]], timeout: Optional[float] = ...) -> Iterator[Future[_T]]: ...