[Vala] Strange recursion behavoir

["Konstantin P." <ria freelander gmail com>]

Hello! I have following C function:
gint apply_properties_to_menu(GList* widgets, GMenuModel* menu)
{
    GList* l;
    GMenuModel* menu_link;
    GtkWidget* menuw;
    int len = g_menu_model_get_n_items(menu);
    int i, j ,ret;
    for (i=0, l=widgets; (i<len) && (l!= NULL); i++,l = l->next)
    {
        while (GTK_IS_SEPARATOR_MENU_ITEM(l->data))
            l = l->next;
        menuw = gtk_menu_item_get_submenu(GTK_MENU_ITEM(l->data));
        menu_link = g_menu_model_get_item_link(menu,i,"submenu");
        if (menuw && menu_link)
        {

apply_properties_to_menu(gtk_container_get_children(GTK_CONTAINER(menuw)),menu_link);
            g_object_unref(menu_link);
        }
        menu_link = g_menu_model_get_item_link(menu,i,"section");
        if (menu_link)
        {
            ret = apply_properties_to_menu(l,menu_link);
            for (j = 0; j < ret; j++)
                l=l->next;
            g_object_unref(menu_link);
        }
        /* Apply some properties */
    }
    return i-1;
}

It works as expected. But straightforward rewrite to vala (below) is not:

public static int apply_menu_properties(List<Widget> widgets, MenuModel
menu)
{
var len = menu.get_n_items();
unowned List<Widget> l;
int i = 0;
for(i = 0, l = widgets;(i<len)&&(l!=null);i++,l=l.next)
{
while (l.data is SeparatorMenuItem) l = l.next;
var menuw = ( l.data as Gtk.MenuItem).get_submenu() as Gtk.Menu;
var submenu = menu.get_item_link(i,"submenu");
if (menuw !=null && submenu !=null)
apply_menu_properties(menuw.get_children(),submenu);
var section = menu.get_item_link(i,"section");
//Here is some strange vala behaviour, that I cannot catch
if (section != null)
{
var ret = apply_menu_properties(l,section);
for (var j=0;j<ret;j++) l = l.next;
}
//end here
        /* Apply some properties */
}
return i-1;
}