Index: Python/ceval.c
===================================================================
--- Python/ceval.c	(revision 69514)
+++ Python/ceval.c	(working copy)
@@ -4119,6 +4119,21 @@
 			t = PySequence_Tuple(stararg);
 			if (t == NULL) {
 				if (PyErr_ExceptionMatches(PyExc_TypeError)) {
+					/* There is possibly a more clarifying
+					 * exception already set. Checking.. */
+					PyTypeObject *star_t = Py_TYPE(stararg);
+					getiterfunc star_it = NULL;
+					if (PyType_HasFeature(star_t,
+							Py_TPFLAGS_HAVE_ITER) &&
+						!PyInstance_Check(stararg)) {
+						star_it = star_t->tp_iter;
+					}
+					if (star_it != NULL ||
+						PySequence_Check(stararg)) {
+						/* Do not override the current
+						 * exception. */
+						goto ext_call_fail;
+					}
 					PyErr_Format(PyExc_TypeError,
 						     "%.200s%.200s argument after * "
 						     "must be a sequence, not %200s",
Index: Lib/test/test_extcall.py
===================================================================
--- Lib/test/test_extcall.py	(revision 69514)
+++ Lib/test/test_extcall.py	(working copy)
@@ -127,6 +127,17 @@
     >>> g(*Nothing())
     0 (1, 2, 3) {}
 
+Checking that the traceback is not being replaced when there is a better
+one available
+
+    >>> def g2():
+    ...     yield iter(None)
+    ...
+    >>> list(*g2())
+    Traceback (most recent call last):
+      ...
+    TypeError: 'NoneType' object is not iterable
+
 Make sure that the function doesn't stomp the dictionary
 
     >>> d = {'a': 1, 'b': 2, 'c': 3}