diff --git a/py/objclosure.c b/py/objclosure.c
index c7d72d4..ec304de 100644
--- a/py/objclosure.c
+++ b/py/objclosure.c
@@ -46,7 +46,7 @@
 
     // need to concatenate closed-over-vars and args
 
-    int n_total = self->n_closed + n_args + 2 * n_kw;
+    mp_uint_t n_total = self->n_closed + n_args + 2 * n_kw;
     if (n_total <= 5) {
         // use stack to allocate temporary args array
         mp_obj_t args2[5];
@@ -68,7 +68,7 @@
 STATIC void closure_print(void (*print)(void *env, const char *fmt, ...), void *env, mp_obj_t o_in, mp_print_kind_t kind) {
     mp_obj_closure_t *o = o_in;
     print(env, "<closure %s at %p, n_closed=%u ", mp_obj_fun_get_name(o->fun), o, o->n_closed);
-    for (int i = 0; i < o->n_closed; i++) {
+    for (mp_uint_t i = 0; i < o->n_closed; i++) {
         if (o->closed[i] == MP_OBJ_NULL) {
             print(env, "(nil)");
         } else {