Implementation of the Map (higher-order function) for generic List collections with tail recursion

mapTailRec.scala

def tMap[T](tail: List[T], f: T => T): List[T] = {

    @tailrec
    def _q(tail: List[T], acc: List[T] = List()): List[T] =     {
      tail match {
        case Nil => rev(acc)
        case x :: xs => {
          _q(xs, f(x) :: acc)
        }
      }
    }

    _q(tail)
  }

  @tailrec
  def rev[T](tail: List[T], acc: List[T] = List()): List[T] = {
    tail match {
      case Nil => acc
      case x :: xs => rev(xs, x :: acc)
    }
  }