pep 484: explicit reexport as intended (#4586)

See discussion on typing-sig.
This doesn't take care of some third_party libraries, will follow up on
those.

Co-authored-by: hauntsaninja <>

stdlib/2/collections.pyi

@@ -1,7 +1,7 @@
 # These are not exported.
 # These are exported.
 from typing import (
-    AbstractSet as Set,
+    AbstractSet,
     Any,
     Callable as Callable,
     Container as Container,
@@ -30,6 +30,8 @@ from typing import (
     overload,
 )
 
+Set = AbstractSet
+
 _S = TypeVar("_S")
 _T = TypeVar("_T")
 _KT = TypeVar("_KT")

stdlib/2/future_builtins.pyi

@@ -1,6 +1,10 @@
-from itertools import ifilter as filter, imap as map, izip as zip
+from itertools import ifilter, imap, izip
 from typing import Any
 
+filter = ifilter
+map = imap
+zip = izip
+
 def ascii(obj: Any) -> str: ...
 def hex(x: int) -> str: ...
 def oct(x: int) -> str: ...

stdlib/2/md5.pyi

@@ -1,6 +1,7 @@
 # Stubs for Python 2.7 md5 stdlib module
 
-from hashlib import md5 as md5, md5 as new
+from hashlib import md5 as md5
 
+new = md5
 blocksize: int
 digest_size: int

stdlib/2/os/__init__.pyi

@@ -1,6 +1,6 @@
 import sys
 from _typeshed import AnyPath, FileDescriptorLike
-from builtins import OSError as error
+from builtins import OSError
 from io import TextIOWrapper as _TextIOWrapper
 from posix import listdir as listdir, stat_result as stat_result  # TODO: use this, see https://github.com/python/mypy/issues/3078
 from typing import (
@@ -35,6 +35,8 @@ _T = TypeVar("_T")
 
 # ----- os variables -----
 
+error = OSError
+
 if sys.version_info >= (3, 2):
     supports_bytes_environ: bool
 
@@ -152,7 +154,9 @@ TMP_MAX: int  # Undocumented, but used by tempfile
 
 # ----- os classes (structures) -----
 if sys.version_info >= (3, 6):
-    from builtins import _PathLike as PathLike  # See comment in builtins
+    from builtins import _PathLike
+
+    PathLike = _PathLike  # See comment in builtins
 
 class _StatVFS(NamedTuple):
     f_bsize: int