diff --git a/python/repeated.c b/python/repeated.c
index 7d797f2a31..b063fcf15c 100644
--- a/python/repeated.c
+++ b/python/repeated.c
@@ -61,7 +61,7 @@ static bool IndexToRange(PyObject* index, Py_ssize_t size, Py_ssize_t* i,
     *step = 0;
     *count = 1;
 
-    if (*i < 0 || *i >= size) {
+    if (*i < 0 || size <= *i) {
       PyErr_Format(PyExc_IndexError, "list index out of range");
       return false;
     }
diff --git a/upb/reflection.c b/upb/reflection.c
index 1792adba36..3f986d5c2b 100644
--- a/upb/reflection.c
+++ b/upb/reflection.c
@@ -398,7 +398,7 @@ bool upb_array_insert(upb_array *arr, size_t i, size_t count,
  */
 void upb_array_delete(upb_array *arr, size_t i, size_t count) {
   size_t end = i + count;
-  UPB_ASSERT(end >= i);
+  UPB_ASSERT(i <= end);
   UPB_ASSERT(end <= arr->len);
   upb_array_move(arr, i, end, arr->len - end);
   arr->len -= count;