[AttributeUsage(AttributeTargets.Class)]
    class MyAtr : Attribute
    {
        public prop : object { get; set; }

        public this(_asd : string)
        {
        }
    }

    [MyAtr("hhh", prop = "zxc")]
    class Test
    {
    }

error : the member `prop' has type object while the value assigned has type string