Extending scala case class without constantly duplicating constructors vals?

Question

As the previous commenter mentioned: case class extension should be avoided but you could convert your Edge class into a trait.

If you want to avoid the private statements you can also mark the variables as override

trait Edge{
  def a:Strl
  def b:Strl
}

case class EdgeQA(override val a:Strl, override val b:Strl, right:Int, asked:Int ) extends Edge

Don’t forget to prefer def over val in traits