*sigh* deal with instances correctly

Lib/test/test_enumerate.py

@@ -141,6 +141,12 @@ class TestReversed(unittest.TestCase):
         # don't allow keyword arguments
         self.assertRaises(TypeError, reversed, [], a=1)
 
+    def test_class_class(self):
+        class A:
+            def __reversed__(self):
+                return [2, 1]
+        self.assertEqual(list(reversed(A())), [2, 1])
+
     def test_xrange_optimization(self):
         x = xrange(1)
         self.assertEqual(type(reversed(x)), type(iter(x)))

Objects/enumobject.c

@@ -232,7 +232,18 @@ reversed_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
 	if (!PyArg_UnpackTuple(args, "reversed", 1, 1, &seq) )
 		return NULL;
 
-	reversed_meth = _PyObject_LookupSpecial(seq, "__reversed__", &reversed_cache);
+	if (PyInstance_Check(seq)) {
+		reversed_meth = PyObject_GetAttrString(seq, "__reversed__");
+		if (reversed_meth == NULL) {
+			if (PyErr_ExceptionMatches(PyExc_AttributeError))
+				PyErr_Clear();
+			else
+				return NULL;
+		}
+	}
+	else
+		reversed_meth = _PyObject_LookupSpecial(seq, "__reversed__",
+							&reversed_cache);
 	if (reversed_meth != NULL) {
 		PyObject *res = PyObject_CallFunctionObjArgs(reversed_meth, NULL);
 		Py_DECREF(reversed_meth);