diff --git a/src/backend/utils/sort/tuplesort.c b/src/backend/utils/sort/tuplesort.c
index b6951d4ac93..1a7a08ea946 100644
--- a/src/backend/utils/sort/tuplesort.c
+++ b/src/backend/utils/sort/tuplesort.c
@@ -3682,6 +3682,9 @@ comparetup_index_btree(const SortTuple *a, const SortTuple *b,
 			return (pos1 < pos2) ? -1 : 1;
 	}
 
+	/* ItemPointer values should never be equal */
+	Assert(false);
+
 	return 0;
 }
 
@@ -3731,6 +3734,9 @@ comparetup_index_hash(const SortTuple *a, const SortTuple *b,
 			return (pos1 < pos2) ? -1 : 1;
 	}
 
+	/* ItemPointer values should never be equal */
+	Assert(false);
+
 	return 0;
 }