How to use Template Parameter at Case Classes - scala

Question

I have a question about Template parameters in Scala with Case Classes.
First working scenario then what I try to achive
object Test1 {
sealed trait Response
final case class StateResponse(state : Any) extend Response
}
abstract class Test1[STATE] {
def something() : Unit = {
...
}
}
Now if use this in the following
import Test1._
result match {
case StateResponse(state) => ...
case _ => ...
}
Everything works fine but probably see what disturbs me, 'Any' at StateResponse. Depending on the implementation class I would like to have concrete State Type then any so..
object Test1Impl {
sealed trait State
final case class Test1State(payload: Map[String, String])
  }
class Test1Impl extends Test1[Test1State] {
}
as you might guess I can't use Template parameter in Test1 in Object Definition but I thought, if I define the case class in class definition, it might work....
object Test1 {
sealed trait Response
}
abstract class Test1[STATE] {
final case class StateResponse(state : STATE) extends Response
def something() : Unit = {
.....
}
}
now until now, Scala Compiler does not complain about anything but when I try
import Test1._
result match {
case StateResponse(state) => ...
case _ => ...
}
then it can't locate 'StateResponse' at case statement and 'Test1.StateResponse' is not helping, so I am doing something illegal, but what?
Or can you tell me how can I make this work?
Thx for answers....

Answer 1

One way is to make StateResponse generic rather than enclosing class
final case class StateResponse[STATE](state : STATE) extends Response
Otherwise, when you make Test1 generic, an instance of StateResponse starts to depend on an instance of Test1
val t = new Test1[Int] {} // you made Test1 abstract, so I had to write {}
val result = t.StateResponse(10)
result match {
case t.StateResponse(state) => println("1")
case _ => println("2")
}
or
import t._
val result = StateResponse(10)
result match {
case StateResponse(state) => println("1")
case _ => println("2")
}