bpo-39168: Remove the __new__ method of typing.Generic (GH-21327)

Automerge-Triggered-By: @gvanrossum
(cherry picked from commit 7fed755)

Co-authored-by: Zackery Spytz <zspytz@gmail.com>

Author: miss-islington

Lib/test/test_typing.py

@@ -1417,8 +1417,6 @@ def test_basics(self):
     def test_generic_errors(self):
         T = TypeVar('T')
         S = TypeVar('S')
-        with self.assertRaises(TypeError):
-            Generic[T]()
         with self.assertRaises(TypeError):
             Generic[T][T]
         with self.assertRaises(TypeError):

Lib/typing.py

@@ -894,16 +894,6 @@ def lookup_name(mapping: Mapping[KT, VT], key: KT, default: VT) -> VT:
     __slots__ = ()
     _is_protocol = False
 
-    def __new__(cls, *args, **kwds):
-        if cls in (Generic, Protocol):
-            raise TypeError(f"Type {cls.__name__} cannot be instantiated; "
-                            "it can be used only as a base class")
-        if super().__new__ is object.__new__ and cls.__init__ is not object.__init__:
-            obj = super().__new__(cls)
-        else:
-            obj = super().__new__(cls, *args, **kwds)
-        return obj
-
     @_tp_cache
     def __class_getitem__(cls, params):
         if not isinstance(params, tuple):

Misc/NEWS.d/next/Library/2020-07-04-21-56-46.bpo-39168.DQWsXj.rst

@@ -0,0 +1 @@
+Remove the ``__new__`` method of :class:`typing.Generic`.