Separate out mp_obj_list_insert for use in display.Group

Note that for some reason this makes the binary 500 bytes larger!

py/objlist.c

@@ -270,7 +270,7 @@ STATIC mp_obj_t list_extend(mp_obj_t self_in, mp_obj_t arg_in) {
     return mp_const_none; // return None, as per CPython
 }
 
-mp_obj_t mp_obj_list_pop(mp_obj_list_t *self, size_t index) {
+inline mp_obj_t mp_obj_list_pop(mp_obj_list_t *self, size_t index) {
     if (self->len == 0) {
         mp_raise_IndexError_varg(translate("pop from empty %q"), MP_QSTR_list);
     }
@@ -375,6 +375,15 @@ STATIC mp_obj_t list_index(size_t n_args, const mp_obj_t *args) {
     return mp_seq_index_obj(self->items, self->len, n_args, args);
 }
 
+inline void mp_obj_list_insert(mp_obj_list_t *self, size_t index, mp_obj_t obj) {
+    mp_obj_list_append(MP_OBJ_FROM_PTR(self), mp_const_none);
+
+    for (size_t i = self->len - 1; i > index; --i) {
+         self->items[i] = self->items[i - 1];
+    }
+    self->items[index] = obj;
+}
+
 STATIC mp_obj_t list_insert(mp_obj_t self_in, mp_obj_t idx, mp_obj_t obj) {
     mp_check_self(MP_OBJ_IS_TYPE(self_in, &mp_type_list));
     mp_obj_list_t *self = mp_instance_cast_to_native_base(self_in, &mp_type_list);
@@ -389,14 +398,7 @@ STATIC mp_obj_t list_insert(mp_obj_t self_in, mp_obj_t idx, mp_obj_t obj) {
     if ((size_t)index > self->len) {
          index = self->len;
     }
-
-    mp_obj_list_append(self_in, mp_const_none);
-
-    for (mp_int_t i = self->len-1; i > index; i--) {
-         self->items[i] = self->items[i-1];
-    }
-    self->items[index] = obj;
-
+    mp_obj_list_insert(self, index, obj);
     return mp_const_none;
 }
 

py/objlist.h

@@ -37,5 +37,6 @@ typedef struct _mp_obj_list_t {
 
 void mp_obj_list_init(mp_obj_list_t *o, size_t n);
 mp_obj_t mp_obj_list_pop(mp_obj_list_t *self, size_t index);
+void mp_obj_list_insert(mp_obj_list_t *self, size_t index, mp_obj_t obj);
 
 #endif // MICROPY_INCLUDED_PY_OBJLIST_H

shared-bindings/displayio/Group.c

@@ -333,7 +333,7 @@ STATIC mp_obj_t displayio_group_obj_sort(size_t n_args, const mp_obj_t *pos_args
     for (size_t i = 1; i < n_args; ++i) {
         args[i] = pos_args[i];
     }
-    args[0] = self->members;
+    args[0] = MP_OBJ_FROM_PTR(self->members);
     return mp_obj_list_sort(n_args, pos_args, kw_args);
 }
 MP_DEFINE_CONST_FUN_OBJ_KW(displayio_group_sort_obj, 1, displayio_group_obj_sort);

shared-module/displayio/Group.c

@@ -314,11 +314,7 @@ static void _remove_layer(displayio_group_t* self, size_t index) {
 
 void common_hal_displayio_group_insert(displayio_group_t* self, size_t index, mp_obj_t layer) {
     _add_layer(self, layer);
-    mp_obj_list_append(self->members, mp_const_none);
-    for (size_t i = self->members->len - 1; i > index; i--) {
-         self->members->items[i] = self->members->items[i - 1];
-    }
-    self->members->items[index] = layer;
+    mp_obj_list_insert(self->members, index, layer);
 }
 
 mp_obj_t common_hal_displayio_group_pop(displayio_group_t* self, size_t index) {