scala – 如何清理“一种类型被推断为’任何”警告？

发布时间：2020-12-16 19:14:43 所属栏目：安全来源：网络整理

导读：我有以下代码： class TestActor() extends RootsActor() { // Receive is a type resolving to PartialFunction[Any,Unit] def rec2 : Actor.Receive = { case "ping" = println("Ping received!!!") } def recAll = List(super.receive,rec2) // Compose p

我有以下代码：

class TestActor() extends RootsActor() {

  // Receive is a type resolving to PartialFunction[Any,Unit]
  def rec2 : Actor.Receive = {   
    case "ping" => println("Ping received!!!")
  }

  def recAll = List(super.receive,rec2)

  // Compose parent class' receive behavior with this class' receive
  override def receive = recAll.reduceLeft { (a,b) => a orElse b }
}

这在运行时正常运行,但会产生以下警告：

[warn] /Users/me/git/proj/roots/src/multi-jvm/scala/stuff/TestActor.scala:18: a type was inferred to be `Any`; this may indicate a programming error.
[warn]  override def receive = recAll.reduceLeft { (a,b) => a orElse b }
[warn]                                                   ^

如何更改此代码以清除警告？

解决方法

我的代码没有收到警告.如果你使用orElse而不减少怎么办？

scala> import akka.actor._
import akka.actor._

scala> class RootActor extends Actor { def receive = { case _ => println("bang") }}
defined class RootActor

scala> class TestActor extends RootActor {
     |   def rec2: Actor.Receive = { case "ping" => println("ping") }
     |   override def receive = super.receive orElse rec2
     | }
defined class TestActor

scala>

（编辑：李大同）

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