A very nice refactoring would be to convert implicit parameters to explicit ones. For example, suppose you have the following class:

object ImplicitTest {

  implicit val myImplicit = "implicit string ";

  def method(x : Int)(implicit y : String) = {
    System.out.println(y + x)
  }

  def main(args : Array[String]) = {
    method(1)
  }

}

It would be nice if I could select the "y" parameter and say "make explicit". The refactor would then produce

object ImplicitTest {

  implicit val myImplicit = "implicit string ";

  def method(x : Int)(y : String) = {
    System.out.println(y + x)
  }

  def main(args : Array[String]) = {
    method(1)(myImplicit)
  }

}

Also, it would be nice to be able to do this for individual invocations, i.e. select the call to "method" and then have the refactor product the following:

object ImplicitTest {

  implicit val myImplicit = "implicit string ";

  def method(x : Int)(implicit y : String) = {
    System.out.println(y + x)
  }

  def main(args : Array[String]) = {
    method(1)(myImplicit)
  }

}

I am not a Scala expert, so I'm not sure if this is always easy/possible. It would be nice to do this for implicit def's as well.