scala - 如何避免推断类型不包含scala wart？

Question

使用 scala wart我得到：

  def lastWithRecursion(input: Seq[Int]): Try[Int] = input match {
      case head :: Nil => Success(head)
      case _ :: tail => lastWithRecursion(tail)
      case _ => Failure(new NoSuchElementException("No such element")) // how to avoid inferred type containing nothing.
  }

如何避免inferred type containing nothing？

Answer 1

尝试添加通用到Failure：

def lastWithRecursion(input: Seq[Int]): Try[Int] = input match {
    case head :: Nil => Success(head)
    case _ :: tail => lastWithRecursion(tail)
    case _ => Failure[Int](new NoSuchElementException("No such element")) // how to avoid inferred type containing nothing.
}