Algebraic Data Types (ADTs) to the rescue.

Here is the destructuring. Note the use of match and case.

object Main {
  def main(args: Array[String]) {
    println(s(One(7)))
    println(s(One("hello")))
    println(s(None))
  }

  def s[X](o: OneOrNone[X]) = o match {
    case One(o) => "got one! " + o
    case None => "don't got one"
  }
}