From: Ivan Levkivskyi <levkivskyi@gmail.com>
Date: Fri, 11 May 2018 03:10:10 +0000 (-0400)
Subject: Fix a bug in Generic.__new__ (GH-6758)
X-Git-Tag: v3.8.0a1~1874
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=b551e9f0ff25018a5606465003e2c51c04f693a3;p=python

Fix a bug in Generic.__new__ (GH-6758)
---

diff --git a/Lib/test/test_typing.py b/Lib/test/test_typing.py
index 46bab5eba6..314716cd7d 100644
--- a/Lib/test/test_typing.py
+++ b/Lib/test/test_typing.py
@@ -1367,6 +1367,9 @@ class GenericTests(BaseTestCase):
         class A(Generic[T]):
             pass
 
+        with self.assertRaises(TypeError):
+            A('foo')
+
         class B:
             def __new__(cls):
                 # call object
diff --git a/Lib/typing.py b/Lib/typing.py
index 89b73db158..8025dfd932 100644
--- a/Lib/typing.py
+++ b/Lib/typing.py
@@ -836,7 +836,7 @@ class Generic:
         if cls is Generic:
             raise TypeError("Type Generic cannot be instantiated; "
                             "it can be used only as a base class")
-        if super().__new__ is object.__new__:
+        if super().__new__ is object.__new__ and cls.__init__ is not object.__init__:
             obj = super().__new__(cls)
         else:
             obj = super().__new__(cls, *args, **kwds)