1 files changed, 19 insertions, 14 deletions

diff --git a/Objects/rangeobject.c b/Objects/rangeobject.c
index c4ba715..899697a 100644
--- a/Objects/rangeobject.c
+++ b/Objects/rangeobject.c
@@ -5,7 +5,7 @@
 
 /* Support objects whose length is > PY_SSIZE_T_MAX.
 
-   This could be sped up for small PyLongs if they fit in an Py_ssize_t.
+   This could be sped up for small PyLongs if they fit in a Py_ssize_t.
    This only matters on Win64.  Though we could use PY_LONG_LONG which
    would presumably help perf.
 */
@@ -406,7 +406,7 @@ range_contains_long(rangeobject *r, PyObject *ob)
     tmp2 = PyNumber_Remainder(tmp1, r->step);
     if (tmp2 == NULL)
         goto end;
-    /* result = (int(ob) - start % step) == 0 */
+    /* result = ((int(ob) - start) % step) == 0 */
     result = PyObject_RichCompareBool(tmp2, zero, Py_EQ);
   end:
     Py_XDECREF(tmp1);
@@ -937,12 +937,20 @@ rangeiter_new(PyTypeObject *type, PyObject *args, PyObject *kw)
 {
     long start, stop, step;
 
-    if (!_PyArg_NoKeywords("rangeiter()", kw))
+    if (!_PyArg_NoKeywords("range_iterator()", kw)) {
         return NULL;
+    }
 
-    if (!PyArg_ParseTuple(args, "lll;rangeiter() requires 3 int arguments",
-                          &start, &stop, &step))
+    if (!PyArg_ParseTuple(args,
+                          "lll;range_iterator() requires 3 int arguments",
+                          &start, &stop, &step)) {
+        return NULL;
+    }
+    if (step == 0) {
+        PyErr_SetString(PyExc_ValueError,
+                        "range_iterator() arg 3 must not be zero");
         return NULL;
+    }
 
     return fast_range_iter(start, stop, step);
 }
@@ -994,15 +1002,14 @@ static PyObject *
 longrangeiter_setstate(longrangeiterobject *r, PyObject *state)
 {
     int cmp;
-   
+
     /* clip the value */
     PyObject *zero = PyLong_FromLong(0);
     if (zero == NULL)
         return NULL;
     cmp = PyObject_RichCompareBool(state, zero, Py_LT);
     if (cmp > 0) {
-        Py_CLEAR(r->index);
-        r->index = zero;
+        Py_XSETREF(r->index, zero);
         Py_RETURN_NONE;
     }
     Py_DECREF(zero);
@@ -1014,10 +1021,9 @@ longrangeiter_setstate(longrangeiterobject *r, PyObject *state)
         return NULL;
     if (cmp > 0)
         state = r->len;
-    
-    Py_CLEAR(r->index);
-    r->index = state;
-    Py_INCREF(r->index);
+
+    Py_INCREF(state);
+    Py_XSETREF(r->index, state);
     Py_RETURN_NONE;
 }
 
@@ -1066,8 +1072,7 @@ longrangeiter_next(longrangeiterobject *r)
     result = PyNumber_Add(r->start, product);
     Py_DECREF(product);
     if (result) {
-        Py_DECREF(r->index);
-        r->index = new_index;
+        Py_SETREF(r->index, new_index);
     }
     else {
         Py_DECREF(new_index);