Schema for `Nothing`

I have the following generic model of responses from a server API:

  sealed trait Status[+E, +A]
  final case class Error[E](error: E) extends Status[E, Nothing]
  final case class Fatal(reason: String) extends Status[Nothing, Nothing]
  final case class Success[A](a: A) extends Status[Nothing, A]
  final case class Timeout() extends Status[Nothing, Nothing]

  implicit def statusSchema[A, E](implicit es: Schema[E], as: Schema[A]): Schema[Status[E, A]] =
    Schema.derived

It works fine if an API method returns something like Status[String, Unit]. But what if some method demoMethod is known not to respond with Error case? It could be encoded as Status[Nothing, Unit]:

  val demoMethod: PublicEndpoint[Args, Unit, Status[Nothing, Unit], Any] =
    basepoint
      .post
      .in("demo-method")
      .in(jsonBody[Args])
      .out(jsonBody[Status[Nothing, Unit]])

For this to work we need a shema for Nothing, in other words the absence of a value.

Currently I use Schema.any as a workaround:

  implicit val nothingSchema: Schema[Nothing] =
    Schema.any

But of course any has not the same meaning as we want.

Start by tracing Schema.derived for the Status[E, A] model and the jsonBody[Status[Nothing, Unit]] usage shown in the report. Compare the current Schema.any workaround with the intended representation of Nothing, and verify that an endpoint returning Status[Nothing, Unit] can derive and use its schema correctly.