When a C library declares a GLib signal like this:

  /**
   * MyObject::my-signal:
   * @self:
   * @items: (type GLib.List) (element-type MyLibrary.Item):
   */
  signals[MY_SIGNAL] =
    g_signal_new ("my-signal",
                  MY_TYPE_OBJECT,
                  G_SIGNAL_RUN_FIRST,
                  G_STRUCT_OFFSET (MyObjectClass, my_signal),
                  NULL,
                  NULL,
                  my_marshal_VOID__POINTER,
                  G_TYPE_NONE,
                  1,
                  G_TYPE_POINTER);

and a signal gets emitted from the C library, signal handlers in javascript will only get a "seed_pointer" because Seed sees "G_TYPE_POINTER" for the first parameter. Seed ignores the annotation saying it is a GList of Item.

seed/libseed/seed-types.c:1299:seed_value_from_gvalue:
    case G_TYPE_POINTER:
      return seed_make_pointer (ctx, g_value_get_pointer (gval));

It seems gjs has the code to make signal work with annotated types:
gjs/gi/value.c:768:gjs_value_from_g_value_internal.

Could we do the same in seed?