The extract parameter refactoring is probably the least mature.

* Adding parameters to methods without parameter lists is currently not implemented because it requires to globally update the according method calls. This is somehow in contrast to the remaining extractions as they solely apply local modifications.
* Extracting whole value definitions is an interesting case, in a sense the current behavior is correct but does probably seldom match the users intention. On the other hand, I don't know if moving the definition to the parameter list could still be seen as an extraction. Probably this could also be generalized to all value extractions:

```
class A{
  def f() = {
    val a = 1 // extract this line
    a
  }
  // extract into this scope
}
```
Would become:
```
class A{
  def f() = {
    a
  }
  val a = 1
}
```