[anonymoushn]

The latter won't work for you as-is:

  scala> def doFoo(x: Some[Int]) = x.get*2
  doFoo: (x: Some[Int])Int

  scala> def doFoo(x: None.type) = None
  doFoo: (x: None.type)None.type

  scala> doFoo(Option(3))
  <console>:9: error: type mismatch;
   found   : Option[Int]
   required: None.type
                doFoo(Option(3))
                            ^

But it will work as either of these:

  scala> def doFoo(x: Option[Int]): Option[Int] = x match {
       |   case Some(n) => Some(n*2)
       |   case _ => None
       | }

  scala> def doFoo(x: Option[Int]) = x.map(_*2)
  doFoo: (x: Option[Int])Option[Int]