2018-08-02

  implicit val sortingDemo4: Ordered[Sorter4] = (sorter: Sorter4) => {
    new Ordered[Sorter4] {
      override def compare(that: Sorter4): Int = {
        if (sorter.fv == that.fv)
          sorter.age - that.age
        else
          that.fv - sorter.fv
      }
    }
  }

case class Sorter4 (age:Int,fv:Int)

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将 implicit val sortingDemo4: Ordered[Sorter4] 中的 : Ordered[Sorter4]删掉之后就能正常运行, 为什么?

  implicit val sortingDemo4: Ordered[Sorter4] = (sorter: Sorter4) => {
    new Ordered[Sorter4] {
      override def compare(that: Sorter4): Int = {
        if (sorter.fv == that.fv)
          sorter.age - that.age
        else
          that.fv - sorter.fv
      }
    }
  }

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