Example:

The following code compiles and works:
    struct Nanana {
      int i;
    }

    class Main {
      static void main() {
        Nanana n = { 42 };
        Value v = n;
        print("%d\n", n.i);
        print("%d\n", ((Nanana)v).i);
      }
    }

The following code compiles, but doesn't work (GLib-GObject-CRITICAL, infinite loop):
    struct N {
      int i;
    }

    class Main {
      static void main() {
        N n = { 42 };
        Value v = n;
        print("%d\n", n.i);
        print("%d\n", ((N)v).i);
      }
    }