diff --git a/src/t_set.c b/src/t_set.c
index 44580098..c974c185 100644
--- a/src/t_set.c
+++ b/src/t_set.c
@@ -144,7 +144,11 @@ void setTypeReleaseIterator(setTypeIterator *si) {
  * Since set elements can be internally be stored as redis objects or
  * simple arrays of integers, setTypeNext returns the encoding of the
  * set object you are iterating, and will populate the appropriate pointer
- * (eobj) or (llobj) accordingly.
+ * (objele) or (llele) accordingly.
+ *
+ * Note that both the objele and llele pointers should be passed and cannot
+ * be NULL since the function will try to defensively populate the non
+ * used field with values which are easy to trap if misused.
  *
  * When there are no longer elements -1 is returned.
  * Returned objects ref count is not incremented, so this function is
@@ -201,6 +205,10 @@ robj *setTypeNextObject(setTypeIterator *si) {
  * field of the object and is used by the caller to check if the
  * int64_t pointer or the redis object pointer was populated.
  *
+ * Note that both the objele and llele pointers should be passed and cannot
+ * be NULL since the function will try to defensively populate the non
+ * used field with values which are easy to trap if misused.
+ *
  * When an object is returned (the set was a real set) the ref count
  * of the object is not incremented so this function can be considered
  * copy on write friendly. */
@@ -246,7 +254,7 @@ void setTypeConvert(robj *setobj, int enc) {
 
         /* To add the elements we extract integers and create redis objects */
         si = setTypeInitIterator(setobj);
-        while (setTypeNext(si,NULL,&intele) != -1) {
+        while (setTypeNext(si,&element,&intele) != -1) {
             element = createStringObjectFromLongLong(intele);
             redisAssertWithInfo(NULL,element,
                                 dictAdd(d,element,NULL) == DICT_OK);