diff -r 3fffe9681f60 Objects/abstract.c
--- a/Objects/abstract.c	Mon Jun 23 15:14:50 2014 +0200
+++ b/Objects/abstract.c	Tue Jun 24 11:48:33 2014 +0200
@@ -82,6 +82,10 @@ PyObject_LengthHint(PyObject *o, Py_ssiz
     PyObject *hint, *result;
     Py_ssize_t res;
     _Py_IDENTIFIER(__length_hint__);
+
+    /* PyErr_Clear() is used below */
+    assert(!PyErr_Occurred());
+
     if (_PyObject_HasLen(o)) {
         res = PyObject_Length(o);
         if (res < 0 && PyErr_Occurred()) {
@@ -280,6 +284,9 @@ PyObject_CheckReadBuffer(PyObject *obj)
     PyBufferProcs *pb = obj->ob_type->tp_as_buffer;
     Py_buffer view;
 
+    /* PyErr_Clear() is used below */
+    assert(!PyErr_Occurred());
+
     if (pb == NULL ||
         pb->bf_getbuffer == NULL)
         return 0;
@@ -1218,7 +1225,12 @@ PyNumber_AsSsize_t(PyObject *item, PyObj
 {
     Py_ssize_t result;
     PyObject *runerr;
-    PyObject *value = PyNumber_Index(item);
+    PyObject *value;
+
+    /* PyErr_Clear() is used below */
+    assert(!PyErr_Occurred());
+
+    value = PyNumber_Index(item);
     if (value == NULL)
         return -1;
 
@@ -1985,6 +1997,9 @@ PyMapping_HasKeyString(PyObject *o, cons
 {
     PyObject *v;
 
+    /* PyErr_Clear() is used below */
+    assert(!PyErr_Occurred());
+
     v = PyMapping_GetItemString(o, key);
     if (v) {
         Py_DECREF(v);
@@ -1999,6 +2014,9 @@ PyMapping_HasKey(PyObject *o, PyObject *
 {
     PyObject *v;
 
+    /* PyErr_Clear() is used below */
+    assert(!PyErr_Occurred());
+
     v = PyObject_GetItem(o, key);
     if (v) {
         Py_DECREF(v);
@@ -2412,6 +2430,9 @@ abstract_get_bases(PyObject *cls)
     _Py_IDENTIFIER(__bases__);
     PyObject *bases;
 
+    /* PyErr_Clear() is used below */
+    assert(!PyErr_Occurred());
+
     Py_ALLOW_RECURSION
     bases = _PyObject_GetAttrId(cls, &PyId___bases__);
     Py_END_ALLOW_RECURSION
@@ -2486,6 +2507,9 @@ recursive_isinstance(PyObject *inst, PyO
     int retval = 0;
     _Py_IDENTIFIER(__class__);
 
+    /* PyErr_Clear() is used below */
+    assert(!PyErr_Occurred());
+
     if (PyType_Check(cls)) {
         retval = PyObject_TypeCheck(inst, (PyTypeObject *)cls);
         if (retval == 0) {
@@ -2691,6 +2715,10 @@ PyObject *
 PyIter_Next(PyObject *iter)
 {
     PyObject *result;
+
+    /* PyErr_Clear() is used below */
+    assert(!PyErr_Occurred());
+
     result = (*iter->ob_type->tp_iternext)(iter);
     if (result == NULL &&
         PyErr_Occurred() &&
diff -r 3fffe9681f60 Objects/rangeobject.c
--- a/Objects/rangeobject.c	Mon Jun 23 15:14:50 2014 +0200
+++ b/Objects/rangeobject.c	Tue Jun 24 11:48:33 2014 +0200
@@ -24,6 +24,9 @@ typedef struct {
 static PyObject *
 validate_step(PyObject *step)
 {
+    /* PyNumber_AsSsize_t() can clear the current exception */
+    assert(!PyErr_Occurred());
+
     /* No step specified, use a step of 1. */
     if (!step)
         return PyLong_FromLong(1);
@@ -116,7 +119,7 @@ range_new(PyTypeObject *type, PyObject *
             Py_DECREF(start);
             return NULL;
         }
-        step = validate_step(step);    /* Caution, this can clear exceptions */
+        step = validate_step(step);
         if (!step) {
             Py_DECREF(start);
             Py_DECREF(stop);
@@ -987,7 +990,7 @@ static PyObject *
 longrangeiter_setstate(longrangeiterobject *r, PyObject *state)
 {
     int cmp;
-   
+
     /* clip the value */
     PyObject *zero = PyLong_FromLong(0);
     if (zero == NULL)
@@ -1007,7 +1010,7 @@ longrangeiter_setstate(longrangeiterobje
         return NULL;
     if (cmp > 0)
         state = r->len;
-    
+
     Py_CLEAR(r->index);
     r->index = state;
     Py_INCREF(r->index);