type Base;
type Derived;
impl Base {
  fn toString() -> String { return "Base"; }
}

impl Derived < Base {
  fn getClosure() -> fn {
    fn closure() -> String {
      return super.toString();
    }
    return closure;
  }

  fn toString() -> String { return "Derived"; }
}

let closure = Derived().getClosure();
println closure(); // out: Base