import java.util.concurrent.atomic.AtomicReference

object UnboundedHub:
  final class Node[A](var value: A, val pointer: AtomicReference[Pointer[A]])
  final case class Pointer[A](node: Node[A], subscribers: Int)

private final class UnboundedHub[A]:
  import UnboundedHub.*

  val publisherHead: AtomicReference[Node[A]] = new AtomicReference(
    new Node[A](
      null.asInstanceOf[A],
      new AtomicReference(
        Pointer(null, 0)
      )
    )
  )

-- Error: /Users/wmazur/projects/scala/community-build3/test.scala:14:15 --------------------------------------------------------------------------------------------------------------------
14 |        Pointer(null, 0)
   |        ^^^^^^^^^^^^^^^^
   |        too many arguments for constructor AtomicReference in class AtomicReference: (): java.util.concurrent.atomic.AtomicReference[UnboundedHub.Pointer[A]]