diff --git a/py/obj.h b/py/obj.h
index 58221bf..88767bf 100644
--- a/py/obj.h
+++ b/py/obj.h
@@ -408,8 +408,8 @@
 } mp_print_kind_t;
 
 typedef void (*mp_print_fun_t)(const mp_print_t *print, mp_obj_t o, mp_print_kind_t kind);
-typedef mp_obj_t (*mp_make_new_fun_t)(mp_obj_t type_in, mp_uint_t n_args, mp_uint_t n_kw, const mp_obj_t *args);
-typedef mp_obj_t (*mp_call_fun_t)(mp_obj_t fun, mp_uint_t n_args, mp_uint_t n_kw, const mp_obj_t *args);
+typedef mp_obj_t (*mp_make_new_fun_t)(mp_obj_t type_in, size_t n_args, size_t n_kw, const mp_obj_t *args);
+typedef mp_obj_t (*mp_call_fun_t)(mp_obj_t fun, size_t n_args, size_t n_kw, const mp_obj_t *args);
 typedef mp_obj_t (*mp_unary_op_fun_t)(mp_uint_t op, mp_obj_t);
 typedef mp_obj_t (*mp_binary_op_fun_t)(mp_uint_t op, mp_obj_t, mp_obj_t);
 typedef void (*mp_attr_fun_t)(mp_obj_t self_in, qstr attr, mp_obj_t *dest);
@@ -691,7 +691,7 @@
 void mp_obj_exception_add_traceback(mp_obj_t self_in, qstr file, size_t line, qstr block);
 void mp_obj_exception_get_traceback(mp_obj_t self_in, size_t *n, size_t **values);
 mp_obj_t mp_obj_exception_get_value(mp_obj_t self_in);
-mp_obj_t mp_obj_exception_make_new(mp_obj_t type_in, mp_uint_t n_args, mp_uint_t n_kw, const mp_obj_t *args);
+mp_obj_t mp_obj_exception_make_new(mp_obj_t type_in, size_t n_args, size_t n_kw, const mp_obj_t *args);
 mp_obj_t mp_alloc_emergency_exception_buf(mp_obj_t size_in);
 void mp_init_emergency_exception_buf(void);
 
diff --git a/py/objarray.c b/py/objarray.c
index 3445bff..2c4813f 100644
--- a/py/objarray.c
+++ b/py/objarray.c
@@ -168,7 +168,7 @@
 #endif
 
 #if MICROPY_PY_ARRAY
-STATIC mp_obj_t array_make_new(mp_obj_t type_in, mp_uint_t n_args, mp_uint_t n_kw, const mp_obj_t *args) {
+STATIC mp_obj_t array_make_new(mp_obj_t type_in, size_t n_args, size_t n_kw, const mp_obj_t *args) {
     (void)type_in;
     mp_arg_check_num(n_args, n_kw, 1, 2, false);
 
@@ -187,7 +187,7 @@
 #endif
 
 #if MICROPY_PY_BUILTINS_BYTEARRAY
-STATIC mp_obj_t bytearray_make_new(mp_obj_t type_in, mp_uint_t n_args, mp_uint_t n_kw, const mp_obj_t *args) {
+STATIC mp_obj_t bytearray_make_new(mp_obj_t type_in, size_t n_args, size_t n_kw, const mp_obj_t *args) {
     (void)type_in;
     mp_arg_check_num(n_args, n_kw, 0, 1, false);
 
@@ -219,7 +219,7 @@
     return MP_OBJ_FROM_PTR(self);
 }
 
-STATIC mp_obj_t memoryview_make_new(mp_obj_t type_in, mp_uint_t n_args, mp_uint_t n_kw, const mp_obj_t *args) {
+STATIC mp_obj_t memoryview_make_new(mp_obj_t type_in, size_t n_args, size_t n_kw, const mp_obj_t *args) {
     (void)type_in;
 
     // TODO possibly allow memoryview constructor to take start/stop so that one
diff --git a/py/objbool.c b/py/objbool.c
index 4276335..09878a7 100644
--- a/py/objbool.c
+++ b/py/objbool.c
@@ -52,7 +52,7 @@
     }
 }
 
-STATIC mp_obj_t bool_make_new(mp_obj_t type_in, mp_uint_t n_args, mp_uint_t n_kw, const mp_obj_t *args) {
+STATIC mp_obj_t bool_make_new(mp_obj_t type_in, size_t n_args, size_t n_kw, const mp_obj_t *args) {
     (void)type_in;
     mp_arg_check_num(n_args, n_kw, 0, 1, false);
 
diff --git a/py/objboundmeth.c b/py/objboundmeth.c
index c191923..c0e75ea 100644
--- a/py/objboundmeth.c
+++ b/py/objboundmeth.c
@@ -47,7 +47,7 @@
 }
 #endif
 
-STATIC mp_obj_t bound_meth_call(mp_obj_t self_in, mp_uint_t n_args, mp_uint_t n_kw, const mp_obj_t *args) {
+STATIC mp_obj_t bound_meth_call(mp_obj_t self_in, size_t n_args, size_t n_kw, const mp_obj_t *args) {
     mp_obj_bound_meth_t *self = MP_OBJ_TO_PTR(self_in);
 
     // need to insert self->self before all other args and then call self->meth
diff --git a/py/objclosure.c b/py/objclosure.c
index e331a65..d556b3b 100644
--- a/py/objclosure.c
+++ b/py/objclosure.c
@@ -36,7 +36,7 @@
     mp_obj_t closed[];
 } mp_obj_closure_t;
 
-STATIC mp_obj_t closure_call(mp_obj_t self_in, mp_uint_t n_args, mp_uint_t n_kw, const mp_obj_t *args) {
+STATIC mp_obj_t closure_call(mp_obj_t self_in, size_t n_args, size_t n_kw, const mp_obj_t *args) {
     mp_obj_closure_t *self = MP_OBJ_TO_PTR(self_in);
 
     // need to concatenate closed-over-vars and args
diff --git a/py/objcomplex.c b/py/objcomplex.c
index e9a15d2..df0467e 100644
--- a/py/objcomplex.c
+++ b/py/objcomplex.c
@@ -69,7 +69,7 @@
     }
 }
 
-STATIC mp_obj_t complex_make_new(mp_obj_t type_in, mp_uint_t n_args, mp_uint_t n_kw, const mp_obj_t *args) {
+STATIC mp_obj_t complex_make_new(mp_obj_t type_in, size_t n_args, size_t n_kw, const mp_obj_t *args) {
     (void)type_in;
     mp_arg_check_num(n_args, n_kw, 0, 2, false);
 
diff --git a/py/objdict.c b/py/objdict.c
index f321750..4010d9c 100644
--- a/py/objdict.c
+++ b/py/objdict.c
@@ -82,7 +82,7 @@
     }
 }
 
-STATIC mp_obj_t dict_make_new(mp_obj_t type_in, mp_uint_t n_args, mp_uint_t n_kw, const mp_obj_t *args) {
+STATIC mp_obj_t dict_make_new(mp_obj_t type_in, size_t n_args, size_t n_kw, const mp_obj_t *args) {
     mp_obj_t dict_out = mp_obj_new_dict(0);
     mp_obj_dict_t *dict = MP_OBJ_TO_PTR(dict_out);
     dict->base.type = MP_OBJ_TO_PTR(type_in);
diff --git a/py/objenumerate.c b/py/objenumerate.c
index 3629c1a..46c3e80 100644
--- a/py/objenumerate.c
+++ b/py/objenumerate.c
@@ -45,7 +45,7 @@
 };
 #define ENUMERATE_MAKE_NEW_NUM_ARGS MP_ARRAY_SIZE(enumerate_make_new_args)
 
-STATIC mp_obj_t enumerate_make_new(mp_obj_t type_in, mp_uint_t n_args, mp_uint_t n_kw, const mp_obj_t *args) {
+STATIC mp_obj_t enumerate_make_new(mp_obj_t type_in, size_t n_args, size_t n_kw, const mp_obj_t *args) {
 #if MICROPY_CPYTHON_COMPAT
     // parse args
     mp_arg_val_t vals[ENUMERATE_MAKE_NEW_NUM_ARGS];
diff --git a/py/objexcept.c b/py/objexcept.c
index ffe5ea0..6e28a98 100644
--- a/py/objexcept.c
+++ b/py/objexcept.c
@@ -114,7 +114,7 @@
     mp_obj_tuple_print(print, MP_OBJ_FROM_PTR(o->args), kind);
 }
 
-mp_obj_t mp_obj_exception_make_new(mp_obj_t type_in, mp_uint_t n_args, mp_uint_t n_kw, const mp_obj_t *args) {
+mp_obj_t mp_obj_exception_make_new(mp_obj_t type_in, size_t n_args, size_t n_kw, const mp_obj_t *args) {
     mp_arg_check_num(n_args, n_kw, 0, MP_OBJ_FUN_ARGS_MAX, false);
     mp_obj_exception_t *o = m_new_obj_var_maybe(mp_obj_exception_t, mp_obj_t, 0);
     if (o == NULL) {
diff --git a/py/objfilter.c b/py/objfilter.c
index cc3083c..168f0e7 100644
--- a/py/objfilter.c
+++ b/py/objfilter.c
@@ -34,7 +34,7 @@
     mp_obj_t iter;
 } mp_obj_filter_t;
 
-STATIC mp_obj_t filter_make_new(mp_obj_t type_in, mp_uint_t n_args, mp_uint_t n_kw, const mp_obj_t *args) {
+STATIC mp_obj_t filter_make_new(mp_obj_t type_in, size_t n_args, size_t n_kw, const mp_obj_t *args) {
     mp_arg_check_num(n_args, n_kw, 2, 2, false);
     mp_obj_filter_t *o = m_new_obj(mp_obj_filter_t);
     o->base.type = MP_OBJ_TO_PTR(type_in);
diff --git a/py/objfloat.c b/py/objfloat.c
index 051c0f6..f144bfd 100644
--- a/py/objfloat.c
+++ b/py/objfloat.c
@@ -69,7 +69,7 @@
     }
 }
 
-STATIC mp_obj_t float_make_new(mp_obj_t type_in, mp_uint_t n_args, mp_uint_t n_kw, const mp_obj_t *args) {
+STATIC mp_obj_t float_make_new(mp_obj_t type_in, size_t n_args, size_t n_kw, const mp_obj_t *args) {
     (void)type_in;
     mp_arg_check_num(n_args, n_kw, 0, 1, false);
 
diff --git a/py/objfun.c b/py/objfun.c
index a574926..f2cc34f 100644
--- a/py/objfun.c
+++ b/py/objfun.c
@@ -52,7 +52,7 @@
 
 // mp_obj_fun_builtin_t defined in obj.h
 
-STATIC mp_obj_t fun_builtin_call(mp_obj_t self_in, mp_uint_t n_args, mp_uint_t n_kw, const mp_obj_t *args) {
+STATIC mp_obj_t fun_builtin_call(mp_obj_t self_in, size_t n_args, size_t n_kw, const mp_obj_t *args) {
     assert(MP_OBJ_IS_TYPE(self_in, &mp_type_fun_builtin));
     mp_obj_fun_builtin_t *self = MP_OBJ_TO_PTR(self_in);
 
@@ -196,7 +196,7 @@
 }
 #endif
 
-STATIC mp_obj_t fun_bc_call(mp_obj_t self_in, mp_uint_t n_args, mp_uint_t n_kw, const mp_obj_t *args) {
+STATIC mp_obj_t fun_bc_call(mp_obj_t self_in, size_t n_args, size_t n_kw, const mp_obj_t *args) {
     MP_STACK_CHECK();
 
     DEBUG_printf("Input n_args: " UINT_FMT ", n_kw: " UINT_FMT "\n", n_args, n_kw);
@@ -353,7 +353,7 @@
 
 #if MICROPY_EMIT_NATIVE
 
-STATIC mp_obj_t fun_native_call(mp_obj_t self_in, mp_uint_t n_args, mp_uint_t n_kw, const mp_obj_t *args) {
+STATIC mp_obj_t fun_native_call(mp_obj_t self_in, size_t n_args, size_t n_kw, const mp_obj_t *args) {
     MP_STACK_CHECK();
     mp_obj_fun_bc_t *self = self_in;
     mp_call_fun_t fun = MICROPY_MAKE_POINTER_CALLABLE((void*)self->bytecode);
@@ -393,7 +393,7 @@
 typedef mp_uint_t (*viper_fun_3_t)(mp_uint_t, mp_uint_t, mp_uint_t);
 typedef mp_uint_t (*viper_fun_4_t)(mp_uint_t, mp_uint_t, mp_uint_t, mp_uint_t);
 
-STATIC mp_obj_t fun_viper_call(mp_obj_t self_in, mp_uint_t n_args, mp_uint_t n_kw, const mp_obj_t *args) {
+STATIC mp_obj_t fun_viper_call(mp_obj_t self_in, size_t n_args, size_t n_kw, const mp_obj_t *args) {
     mp_obj_fun_viper_t *self = self_in;
 
     mp_arg_check_num(n_args, n_kw, self->n_args, self->n_args, false);
@@ -514,7 +514,7 @@
     return MP_OBJ_NEW_SMALL_INT(val);
 }
 
-STATIC mp_obj_t fun_asm_call(mp_obj_t self_in, mp_uint_t n_args, mp_uint_t n_kw, const mp_obj_t *args) {
+STATIC mp_obj_t fun_asm_call(mp_obj_t self_in, size_t n_args, size_t n_kw, const mp_obj_t *args) {
     mp_obj_fun_asm_t *self = self_in;
 
     mp_arg_check_num(n_args, n_kw, self->n_args, self->n_args, false);
diff --git a/py/objgenerator.c b/py/objgenerator.c
index 0a68485..91936f9 100644
--- a/py/objgenerator.c
+++ b/py/objgenerator.c
@@ -49,7 +49,7 @@
     mp_code_state code_state;
 } mp_obj_gen_instance_t;
 
-STATIC mp_obj_t gen_wrap_call(mp_obj_t self_in, mp_uint_t n_args, mp_uint_t n_kw, const mp_obj_t *args) {
+STATIC mp_obj_t gen_wrap_call(mp_obj_t self_in, size_t n_args, size_t n_kw, const mp_obj_t *args) {
     mp_obj_gen_wrap_t *self = MP_OBJ_TO_PTR(self_in);
     mp_obj_fun_bc_t *self_fun = (mp_obj_fun_bc_t*)self->fun;
     assert(self_fun->base.type == &mp_type_fun_bc);
diff --git a/py/objint.c b/py/objint.c
index 57fe364..7ee7653 100644
--- a/py/objint.c
+++ b/py/objint.c
@@ -42,7 +42,7 @@
 #endif
 
 // This dispatcher function is expected to be independent of the implementation of long int
-STATIC mp_obj_t mp_obj_int_make_new(mp_obj_t type_in, mp_uint_t n_args, mp_uint_t n_kw, const mp_obj_t *args) {
+STATIC mp_obj_t mp_obj_int_make_new(mp_obj_t type_in, size_t n_args, size_t n_kw, const mp_obj_t *args) {
     (void)type_in;
     mp_arg_check_num(n_args, n_kw, 0, 2, false);
 
diff --git a/py/objlist.c b/py/objlist.c
index d0641f2..059fec1 100644
--- a/py/objlist.c
+++ b/py/objlist.c
@@ -68,7 +68,7 @@
     return list;
 }
 
-STATIC mp_obj_t list_make_new(mp_obj_t type_in, mp_uint_t n_args, mp_uint_t n_kw, const mp_obj_t *args) {
+STATIC mp_obj_t list_make_new(mp_obj_t type_in, size_t n_args, size_t n_kw, const mp_obj_t *args) {
     (void)type_in;
     mp_arg_check_num(n_args, n_kw, 0, 1, false);
 
diff --git a/py/objmap.c b/py/objmap.c
index 6dbfaca..a0293c3 100644
--- a/py/objmap.c
+++ b/py/objmap.c
@@ -36,7 +36,7 @@
     mp_obj_t iters[];
 } mp_obj_map_t;
 
-STATIC mp_obj_t map_make_new(mp_obj_t type_in, mp_uint_t n_args, mp_uint_t n_kw, const mp_obj_t *args) {
+STATIC mp_obj_t map_make_new(mp_obj_t type_in, size_t n_args, size_t n_kw, const mp_obj_t *args) {
     mp_arg_check_num(n_args, n_kw, 2, MP_OBJ_FUN_ARGS_MAX, false);
     mp_obj_map_t *o = m_new_obj_var(mp_obj_map_t, mp_obj_t, n_args - 1);
     o->base.type = MP_OBJ_TO_PTR(type_in);
diff --git a/py/objnamedtuple.c b/py/objnamedtuple.c
index 167e23b..3e34603 100644
--- a/py/objnamedtuple.c
+++ b/py/objnamedtuple.c
@@ -77,7 +77,7 @@
     }
 }
 
-STATIC mp_obj_t namedtuple_make_new(mp_obj_t type_in, mp_uint_t n_args, mp_uint_t n_kw, const mp_obj_t *args) {
+STATIC mp_obj_t namedtuple_make_new(mp_obj_t type_in, size_t n_args, size_t n_kw, const mp_obj_t *args) {
     mp_obj_namedtuple_type_t *type = MP_OBJ_TO_PTR(type_in);
     mp_uint_t num_fields = type->n_fields;
     if (n_args + n_kw != num_fields) {
diff --git a/py/objobject.c b/py/objobject.c
index afb9d5a..5cd3773 100644
--- a/py/objobject.c
+++ b/py/objobject.c
@@ -33,7 +33,7 @@
     mp_obj_base_t base;
 } mp_obj_object_t;
 
-STATIC mp_obj_t object_make_new(mp_obj_t type_in, mp_uint_t n_args, mp_uint_t n_kw, const mp_obj_t *args) {
+STATIC mp_obj_t object_make_new(mp_obj_t type_in, size_t n_args, size_t n_kw, const mp_obj_t *args) {
     (void)args;
     mp_arg_check_num(n_args, n_kw, 0, 0, false);
     mp_obj_object_t *o = m_new_obj(mp_obj_object_t);
diff --git a/py/objproperty.c b/py/objproperty.c
index fb814cb..323696c 100644
--- a/py/objproperty.c
+++ b/py/objproperty.c
@@ -37,7 +37,7 @@
     mp_obj_t proxy[3]; // getter, setter, deleter
 } mp_obj_property_t;
 
-STATIC mp_obj_t property_make_new(mp_obj_t type_in, mp_uint_t n_args, mp_uint_t n_kw, const mp_obj_t *args) {
+STATIC mp_obj_t property_make_new(mp_obj_t type_in, size_t n_args, size_t n_kw, const mp_obj_t *args) {
     mp_arg_check_num(n_args, n_kw, 0, 4, false);
 
     mp_obj_property_t *o = m_new_obj(mp_obj_property_t);
diff --git a/py/objrange.c b/py/objrange.c
index 7a4aaa7..bec026f 100644
--- a/py/objrange.c
+++ b/py/objrange.c
@@ -90,7 +90,7 @@
     }
 }
 
-STATIC mp_obj_t range_make_new(mp_obj_t type_in, mp_uint_t n_args, mp_uint_t n_kw, const mp_obj_t *args) {
+STATIC mp_obj_t range_make_new(mp_obj_t type_in, size_t n_args, size_t n_kw, const mp_obj_t *args) {
     mp_arg_check_num(n_args, n_kw, 1, 3, false);
 
     mp_obj_range_t *o = m_new_obj(mp_obj_range_t);
diff --git a/py/objreversed.c b/py/objreversed.c
index 2b16f08..b0da00a 100644
--- a/py/objreversed.c
+++ b/py/objreversed.c
@@ -38,7 +38,7 @@
     mp_uint_t cur_index;    // current index, plus 1; 0=no more, 1=last one (index 0)
 } mp_obj_reversed_t;
 
-STATIC mp_obj_t reversed_make_new(mp_obj_t type_in, mp_uint_t n_args, mp_uint_t n_kw, const mp_obj_t *args) {
+STATIC mp_obj_t reversed_make_new(mp_obj_t type_in, size_t n_args, size_t n_kw, const mp_obj_t *args) {
     mp_arg_check_num(n_args, n_kw, 1, 1, false);
 
     // check if __reversed__ exists, and if so delegate to it
diff --git a/py/objset.c b/py/objset.c
index fbcf0cd..6ac9c58 100644
--- a/py/objset.c
+++ b/py/objset.c
@@ -119,7 +119,7 @@
     #endif
 }
 
-STATIC mp_obj_t set_make_new(mp_obj_t type_in, mp_uint_t n_args, mp_uint_t n_kw, const mp_obj_t *args) {
+STATIC mp_obj_t set_make_new(mp_obj_t type_in, size_t n_args, size_t n_kw, const mp_obj_t *args) {
     mp_arg_check_num(n_args, n_kw, 0, 1, false);
 
     switch (n_args) {
diff --git a/py/objstr.c b/py/objstr.c
index c4335bb..55c7cdd 100644
--- a/py/objstr.c
+++ b/py/objstr.c
@@ -131,7 +131,7 @@
     }
 }
 
-mp_obj_t mp_obj_str_make_new(mp_obj_t type_in, mp_uint_t n_args, mp_uint_t n_kw, const mp_obj_t *args) {
+mp_obj_t mp_obj_str_make_new(mp_obj_t type_in, size_t n_args, size_t n_kw, const mp_obj_t *args) {
 #if MICROPY_CPYTHON_COMPAT
     if (n_kw != 0) {
         mp_arg_error_unimpl_kw();
@@ -169,7 +169,7 @@
     }
 }
 
-STATIC mp_obj_t bytes_make_new(mp_obj_t type_in, mp_uint_t n_args, mp_uint_t n_kw, const mp_obj_t *args) {
+STATIC mp_obj_t bytes_make_new(mp_obj_t type_in, size_t n_args, size_t n_kw, const mp_obj_t *args) {
     (void)type_in;
 
     #if MICROPY_CPYTHON_COMPAT
diff --git a/py/objstr.h b/py/objstr.h
index d9cc85e..d9327b1 100644
--- a/py/objstr.h
+++ b/py/objstr.h
@@ -60,7 +60,7 @@
     else { str_len = ((mp_obj_str_t*)MP_OBJ_TO_PTR(str_obj_in))->len; str_data = ((mp_obj_str_t*)MP_OBJ_TO_PTR(str_obj_in))->data; }
 #endif
 
-mp_obj_t mp_obj_str_make_new(mp_obj_t type_in, mp_uint_t n_args, mp_uint_t n_kw, const mp_obj_t *args);
+mp_obj_t mp_obj_str_make_new(mp_obj_t type_in, size_t n_args, size_t n_kw, const mp_obj_t *args);
 void mp_str_print_json(const mp_print_t *print, const byte *str_data, size_t str_len);
 mp_obj_t mp_obj_str_format(mp_uint_t n_args, const mp_obj_t *args, mp_map_t *kwargs);
 mp_obj_t mp_obj_str_split(mp_uint_t n_args, const mp_obj_t *args);
diff --git a/py/objstringio.c b/py/objstringio.c
index 5a8f43d..d046cdd 100644
--- a/py/objstringio.c
+++ b/py/objstringio.c
@@ -128,7 +128,7 @@
     return o;
 }
 
-STATIC mp_obj_t stringio_make_new(mp_obj_t type_in, mp_uint_t n_args, mp_uint_t n_kw, const mp_obj_t *args) {
+STATIC mp_obj_t stringio_make_new(mp_obj_t type_in, size_t n_args, size_t n_kw, const mp_obj_t *args) {
     (void)n_kw; // TODO check n_kw==0
     mp_obj_stringio_t *o = stringio_new(type_in);
 
diff --git a/py/objtuple.c b/py/objtuple.c
index de2bfc3..8337b67 100644
--- a/py/objtuple.c
+++ b/py/objtuple.c
@@ -61,7 +61,7 @@
     }
 }
 
-STATIC mp_obj_t mp_obj_tuple_make_new(mp_obj_t type_in, mp_uint_t n_args, mp_uint_t n_kw, const mp_obj_t *args) {
+STATIC mp_obj_t mp_obj_tuple_make_new(mp_obj_t type_in, size_t n_args, size_t n_kw, const mp_obj_t *args) {
     (void)type_in;
 
     mp_arg_check_num(n_args, n_kw, 0, 1, false);
diff --git a/py/objtype.c b/py/objtype.c
index ca52006..c9ab596 100644
--- a/py/objtype.c
+++ b/py/objtype.c
@@ -43,7 +43,7 @@
 #define DEBUG_printf(...) (void)0
 #endif
 
-STATIC mp_obj_t static_class_method_make_new(mp_obj_t self_in, mp_uint_t n_args, mp_uint_t n_kw, const mp_obj_t *args);
+STATIC mp_obj_t static_class_method_make_new(mp_obj_t self_in, size_t n_args, size_t n_kw, const mp_obj_t *args);
 
 /******************************************************************************/
 // instance object
@@ -235,7 +235,7 @@
     mp_printf(print, "<%s object at %p>", mp_obj_get_type_str(self_in), self_in);
 }
 
-mp_obj_t mp_obj_instance_make_new(mp_obj_t self_in, mp_uint_t n_args, mp_uint_t n_kw, const mp_obj_t *args) {
+mp_obj_t mp_obj_instance_make_new(mp_obj_t self_in, size_t n_args, size_t n_kw, const mp_obj_t *args) {
     assert(MP_OBJ_IS_TYPE(self_in, &mp_type_type));
     mp_obj_type_t *self = MP_OBJ_TO_PTR(self_in);
     assert(mp_obj_is_instance_type(self));
@@ -707,7 +707,7 @@
     return mp_obj_instance_get_call(self_in) != MP_OBJ_NULL;
 }
 
-mp_obj_t mp_obj_instance_call(mp_obj_t self_in, mp_uint_t n_args, mp_uint_t n_kw, const mp_obj_t *args) {
+mp_obj_t mp_obj_instance_call(mp_obj_t self_in, size_t n_args, size_t n_kw, const mp_obj_t *args) {
     mp_obj_t call = mp_obj_instance_get_call(self_in);
     if (call == MP_OBJ_NULL) {
         if (MICROPY_ERROR_REPORTING == MICROPY_ERROR_REPORTING_TERSE) {
@@ -778,7 +778,7 @@
     mp_printf(print, "<class '%q'>", self->name);
 }
 
-STATIC mp_obj_t type_make_new(mp_obj_t type_in, mp_uint_t n_args, mp_uint_t n_kw, const mp_obj_t *args) {
+STATIC mp_obj_t type_make_new(mp_obj_t type_in, size_t n_args, size_t n_kw, const mp_obj_t *args) {
     (void)type_in;
 
     mp_arg_check_num(n_args, n_kw, 1, 3, false);
@@ -798,7 +798,7 @@
     }
 }
 
-STATIC mp_obj_t type_call(mp_obj_t self_in, mp_uint_t n_args, mp_uint_t n_kw, const mp_obj_t *args) {
+STATIC mp_obj_t type_call(mp_obj_t self_in, size_t n_args, size_t n_kw, const mp_obj_t *args) {
     // instantiate an instance of a class
 
     mp_obj_type_t *self = MP_OBJ_TO_PTR(self_in);
@@ -957,7 +957,7 @@
     mp_print_str(print, ">");
 }
 
-STATIC mp_obj_t super_make_new(mp_obj_t type_in, mp_uint_t n_args, mp_uint_t n_kw, const mp_obj_t *args) {
+STATIC mp_obj_t super_make_new(mp_obj_t type_in, size_t n_args, size_t n_kw, const mp_obj_t *args) {
     (void)type_in;
     // 0 arguments are turned into 2 in the compiler
     // 1 argument is not yet implemented
@@ -1108,7 +1108,7 @@
 /******************************************************************************/
 // staticmethod and classmethod types (probably should go in a different file)
 
-STATIC mp_obj_t static_class_method_make_new(mp_obj_t self_in, mp_uint_t n_args, mp_uint_t n_kw, const mp_obj_t *args) {
+STATIC mp_obj_t static_class_method_make_new(mp_obj_t self_in, size_t n_args, size_t n_kw, const mp_obj_t *args) {
     mp_obj_type_t *self = MP_OBJ_TO_PTR(self_in);
     assert(self == &mp_type_staticmethod || self == &mp_type_classmethod);
 
diff --git a/py/objtype.h b/py/objtype.h
index 6023e8d..06227cf 100644
--- a/py/objtype.h
+++ b/py/objtype.h
@@ -42,11 +42,11 @@
 
 // these need to be exposed so mp_obj_is_callable can work correctly
 bool mp_obj_instance_is_callable(mp_obj_t self_in);
-mp_obj_t mp_obj_instance_call(mp_obj_t self_in, mp_uint_t n_args, mp_uint_t n_kw, const mp_obj_t *args);
+mp_obj_t mp_obj_instance_call(mp_obj_t self_in, size_t n_args, size_t n_kw, const mp_obj_t *args);
 
 #define mp_obj_is_instance_type(type) ((type)->make_new == mp_obj_instance_make_new)
 #define mp_obj_is_native_type(type) ((type)->make_new != mp_obj_instance_make_new)
 // this needs to be exposed for the above macros to work correctly
-mp_obj_t mp_obj_instance_make_new(mp_obj_t self_in, mp_uint_t n_args, mp_uint_t n_kw, const mp_obj_t *args);
+mp_obj_t mp_obj_instance_make_new(mp_obj_t self_in, size_t n_args, size_t n_kw, const mp_obj_t *args);
 
 #endif // __MICROPY_INCLUDED_PY_OBJTYPE_H__
diff --git a/py/objzip.c b/py/objzip.c
index 3ac6af1..4b240fb 100644
--- a/py/objzip.c
+++ b/py/objzip.c
@@ -36,7 +36,7 @@
     mp_obj_t iters[];
 } mp_obj_zip_t;
 
-STATIC mp_obj_t zip_make_new(mp_obj_t type_in, mp_uint_t n_args, mp_uint_t n_kw, const mp_obj_t *args) {
+STATIC mp_obj_t zip_make_new(mp_obj_t type_in, size_t n_args, size_t n_kw, const mp_obj_t *args) {
     mp_arg_check_num(n_args, n_kw, 0, MP_OBJ_FUN_ARGS_MAX, false);
 
     mp_obj_zip_t *o = m_new_obj_var(mp_obj_zip_t, mp_obj_t, n_args);
diff --git a/py/runtime.c b/py/runtime.c
index c97710b..b0f407a 100644
--- a/py/runtime.c
+++ b/py/runtime.c
@@ -894,7 +894,7 @@
     mp_obj_t fun;
 } mp_obj_checked_fun_t;
 
-STATIC mp_obj_t checked_fun_call(mp_obj_t self_in, mp_uint_t n_args, mp_uint_t n_kw, const mp_obj_t *args) {
+STATIC mp_obj_t checked_fun_call(mp_obj_t self_in, size_t n_args, size_t n_kw, const mp_obj_t *args) {
     mp_obj_checked_fun_t *self = MP_OBJ_TO_PTR(self_in);
     if (n_args > 0) {
         const mp_obj_type_t *arg0_type = mp_obj_get_type(args[0]);