bug from apply lambda

[NaoEhSavio]

The problem is in applying lambda that doesn't reduce... ex:

IO.prompt (question: String) : IO String {
  do IO {
    IO.output question
    ask answer = IO.input
    return answer
  }
}

Main {
  IO.prompt "hey"
}

the return without reduced lambda

(IO.do_output "hey" λ* (IO.do_input λx0 (IO.done x0)))