2 files changed, 9 insertions, 1 deletions
diff --git a/Objects/rangeobject.c b/Objects/rangeobject.c
index 8e74132..e7c3709 100644
--- a/Objects/rangeobject.c
+++ b/Objects/rangeobject.c
@@ -399,7 +399,7 @@ 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);
diff --git a/Objects/setobject.c b/Objects/setobject.c
index 6dd403f..5846045 100644
--- a/Objects/setobject.c
+++ b/Objects/setobject.c
@@ -1476,6 +1476,10 @@ PyDoc_STRVAR(isdisjoint_doc,
 static int
 set_difference_update_internal(PySetObject *so, PyObject *other)
 {
+    if (PySet_GET_SIZE(so) == 0) {
+        return 0;
+    }
+
     if ((PyObject *)so == other)
         return set_clear_internal(so);
 
@@ -1550,6 +1554,10 @@ set_difference(PySetObject *so, PyObject *other)
     Py_ssize_t pos = 0;
     int rv;
 
+    if (PySet_GET_SIZE(so) == 0) {
+        return set_copy(so);
+    }
+
     if (!PyAnySet_Check(other)  && !PyDict_CheckExact(other)) {
         return set_copy_and_difference(so, other);
     }