-- iteration 24: `actor M` erases the class, so `call`'s reply type is
-- only defined when every receive(msg: M) program-wide agrees on one
-- return type. Two classes disagreeing is WO-E226 naming both.

class Q {
  n: Int
}

class IntAnswer {
  pad: Int
  fn receive(msg: Q) -> Int {
    return msg.n;
  }
}

class BoolAnswer {
  pad: Int
  fn receive(msg: Q) -> Bool {
    return msg.n > 0;
  }
}

fn main() -> Int {
  let a: actor Q = spawn IntAnswer { pad: 0 };
  let r = call(a, Q { n: 1 });
  return r;
}