How to correctly type-annotate this HList?
sealed abstract trait HList case class :+:[H, T <: HList](head: H, tail: T) extends HList { def :+:[T](v: T) = new :+:(v, this) } case object HNil extends HList { def :+:[T](v: T) = new :+:(v, this) } object HListExpt { def main(args: Array[String]) { val me: String :+: Int :+: Symbol :+: HNil.type = "Rahul" :+: 20 :+: 'Male...