diff --git a/py/obj.c b/py/obj.c
index 4b5fe25..98ffa93 100644
--- a/py/obj.c
+++ b/py/obj.c
@@ -321,7 +321,7 @@
 #endif
 
 // note: returned value in *items may point to the interior of a GC block
-void mp_obj_get_array(mp_obj_t o, mp_uint_t *len, mp_obj_t **items) {
+void mp_obj_get_array(mp_obj_t o, size_t *len, mp_obj_t **items) {
     if (MP_OBJ_IS_TYPE(o, &mp_type_tuple)) {
         mp_obj_tuple_get(o, len, items);
     } else if (MP_OBJ_IS_TYPE(o, &mp_type_list)) {
@@ -338,7 +338,7 @@
 
 // note: returned value in *items may point to the interior of a GC block
 void mp_obj_get_array_fixed_n(mp_obj_t o, size_t len, mp_obj_t **items) {
-    mp_uint_t seq_len;
+    size_t seq_len;
     mp_obj_get_array(o, &seq_len, items);
     if (seq_len != len) {
         if (MICROPY_ERROR_REPORTING == MICROPY_ERROR_REPORTING_TERSE) {