Patternmatch Unreachable Warning about scala3 HOT 2 OPEN

sealed trait T_A[A, B]
sealed trait T_B[C]
case class CC_D[A, C]() extends T_A[A, C]
case class CC_E() extends T_B
case class CC_G[A, C](c: C) extends T_A[A, C]
@main def main = {
  val v_a: T_A[Boolean, T_B[Boolean]] = CC_G(null)
  val v_b = v_a match {
    case CC_D()  => 0
    case CC_G(_) => 1
  }
  println(s"the unreachable case v_b: $v_b")
}