Get constructor parameter values using scala reflection

Working in a codebase with scala that wants you, for certain classes, to define a sort of "make a new version" - so for instance if you have a class x(a :int, b:String, c:double)... it would have a function like this:

class x( a: Integer, b : String, c : Double) extends CanMakeNew
{
    def newValue() = x( a, b, c)
}

I have no control over that - but would prefer not to implement it every time. Or, well... ever. Is there a way in scala, with reflection - to iterate over the constructor parameter values? I can use reflection to look at the parameter types - but as parameternames has not been turned on for this module, and I can't turn it on - I can't correlate those with the stored values in the class. Fundamentally, I'm looking for anyway of implementing a trait like:

trait CanMakeNewDoneForMe extends CanMakeNew {
    def newValue()  {I need the code that goes here}

So does scala reflection have any way of either inspecting the constructor or inspecting the object and seeing "ahh, this was the third parameter in the constructor"?