Cheap Options in dotty?

Option.scala

type Option[A] = A | Null

object Option {
  inline def apply[A](x: A): Option[A] = x
}

implicit class OptionMethods[A](val x: Option[A]) extends AnyVal {

  inline def map[B](f: A => B): Option[A] = x match {
    case null => null
    case a => f(a)
  }
  
  inline def flatMap[B](f: A => Option[B]): Option[B] = x match {
    case null => null
    case a => f(a)
  }
  
  inline def filter(f: A => Boolean): Option[A] = if (f(x)) x else null
  
  inline def getOrElse(default: A): A = x match {
    case null => default
    case a => a
  }
}