diff -r 784fea019cab Lib/test/test_descr.py
--- a/Lib/test/test_descr.py	Wed Nov 09 18:57:00 2016 -0500
+++ b/Lib/test/test_descr.py	Thu Nov 10 21:47:39 2016 +0800
@@ -1284,7 +1284,7 @@
             del X().a
 
     def test_slots_special(self):
-        # Testing __dict__ and __weakref__ in __slots__...
+        # Testing special slots like __dict__ and __weakref__ in __slots__
         class D(object):
             __slots__ = ["__dict__"]
         a = D()
@@ -1305,6 +1305,27 @@
         else:
             self.fail("shouldn't be allowed to set a.foo")
 
+        class Q:
+            __slots__ = ["__qualname__"]
+        a = Q()
+        self.assertNotHasAttr(a, "__qualname__")
+        a.__qualname__ = "a"
+        self.assertEqual(a.__qualname__, "a")
+        self.assertEqual(Q.__qualname__, D.__qualname__[:-1] + "Q")
+
+        class L1:
+            def __init__(self):
+                self.b = 42
+        class L2(L1):
+            __slots__ = ["__classcell__"]
+            def __init__(self):
+                super().__init__()
+        a = L2()
+        self.assertEqual(a.b, 42)
+        self.assertNotHasAttr(a, "__classcell__")
+        a.__classcell__ = 42
+        self.assertEqual(a.__classcell__, 42)
+
         class C1(W, D):
             __slots__ = []
         a = C1()
diff -r 784fea019cab Objects/typeobject.c
--- a/Objects/typeobject.c	Wed Nov 09 18:57:00 2016 -0500
+++ b/Objects/typeobject.c	Thu Nov 10 21:47:39 2016 +0800
@@ -2444,7 +2444,12 @@
                 goto error;
             }
             PyList_SET_ITEM(newslots, j, tmp);
-            if (PyDict_GetItem(dict, tmp)) {
+            /* CPython inserts __qualname__ and __classcell__ (when needed)
+               into the namespace when creating a class. They will be deleted
+               below so won't act as a class variable.*/
+            if (PyDict_GetItem(dict, tmp) &&
+                _PyUnicode_CompareWithId(tmp, &PyId___qualname__) != 0 &&
+                _PyUnicode_CompareWithId(tmp, &PyId___classcell__) != 0) {
                 PyErr_Format(PyExc_ValueError,
                              "%R in __slots__ conflicts with class variable",
                              tmp);