[Python-checkins] bpo-46244: Remove __slots__ from typing.TypeVar, .ParamSpec (#30444)

[Fidget-Spinner]

https://github.com/python/cpython/commit/081a2140083680ffc309e53699aea29e71760d70
commit: 081a2140083680ffc309e53699aea29e71760d70
branch: main
author: Arie Bovenberg <a.c.bovenberg at gmail.com>
committer: Fidget-Spinner <28750310+Fidget-Spinner at users.noreply.github.com>
date: 2022-01-11T07:43:39+08:00
summary:

bpo-46244: Remove __slots__ from typing.TypeVar, .ParamSpec (#30444)

* add missing __slots__ to typing._TypeVarLike

* add news entry

* remove slots from _TypeVarLike base classes

* cleanup diff

* fix broken link in blurb

files:
A Misc/NEWS.d/next/Library/2022-01-06-21-31-14.bpo-46244.hjyfJj.rst
M Lib/typing.py

diff --git a/Lib/typing.py b/Lib/typing.py
index ae1dd5c2d7689..d520f6b2e1b3d 100644
--- a/Lib/typing.py
+++ b/Lib/typing.py
@@ -805,9 +805,6 @@ def longest(x: A, y: A) -> A:
     Note that only type variables defined in global scope can be pickled.
     """
 
-    __slots__ = ('__name__', '__bound__', '__constraints__',
-                 '__covariant__', '__contravariant__', '__dict__')
-
     def __init__(self, name, *constraints, bound=None,
                  covariant=False, contravariant=False):
         self.__name__ = name
@@ -907,9 +904,6 @@ def add_two(x: float, y: float) -> float:
     be pickled.
     """
 
-    __slots__ = ('__name__', '__bound__', '__covariant__', '__contravariant__',
-                 '__dict__')
-
     @property
     def args(self):
         return ParamSpecArgs(self)
diff --git a/Misc/NEWS.d/next/Library/2022-01-06-21-31-14.bpo-46244.hjyfJj.rst b/Misc/NEWS.d/next/Library/2022-01-06-21-31-14.bpo-46244.hjyfJj.rst
new file mode 100644
index 0000000000000..5ca536a97c9cd
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2022-01-06-21-31-14.bpo-46244.hjyfJj.rst
@@ -0,0 +1,2 @@
+Removed ``__slots__`` from :class:`typing.ParamSpec` and :class:`typing.TypeVar`.
+They served no purpose. Patch by Arie Bovenberg.