Index: Objects/bytearrayobject.c
===================================================================
--- Objects/bytearrayobject.c	(revision 80103)
+++ Objects/bytearrayobject.c	(working copy)
@@ -636,6 +636,11 @@
         needed = 0;
     }
     else if (values == (PyObject *)self || !PyByteArray_Check(values)) {
+        if(PyNumber_Check(values)) {
+            PyErr_SetString(PyExc_TypeError,
+                            "can assign only encoded strings, buffers, and iterables");
+            return -1;
+        }
         /* Make a copy an call this function recursively */
         int err;
         values = PyByteArray_FromObject(values);
Index: Lib/test/test_bytes.py
===================================================================
--- Lib/test/test_bytes.py	(revision 80103)
+++ Lib/test/test_bytes.py	(working copy)
@@ -564,6 +564,9 @@
         b[3:0] = [42, 42, 42]
         self.assertEqual(b, bytearray([0, 1, 2, 42, 42, 42, 3, 4, 5, 6, 7, 8, 9]))
 
+        with self.assertRaises(TypeError):
+            b[3:4] = 5
+
     def test_extended_set_del_slice(self):
         indices = (0, None, 1, 3, 19, 300, 1<<333, -1, -2, -31, -300)
         for start in indices: