抽象类型模式是未经检查的，因为它被擦除消除 [英] abstract type pattern is unchecked since it is eliminated by erasure

问题描述

谁能告诉我如何避免下面代码块中的警告:

Could someone tell me how can I avoid the warning in the code block below:

abstract class Foo[T <: Bar]{
  case class CaseClass[T <: Bar](t: T)
  def method1 = {
    case CaseClass(t: T) => println(t)
    csse _ => 
  }
}

这会导致编译器警告:

 abstract type pattern T is unchecked since it is eliminated by erasure
 case CaseClass(t: T) => println(t)
                   ^

推荐答案

您可以使用 ClassTag(或 TypeTag):

You could use ClassTag (or TypeTag):

import scala.reflect.ClassTag

abstract class Foo[T <: Bar : ClassTag]{
  ...
  val clazz = implicitly[ClassTag[T]].runtimeClass
  def method1 = {
    case CaseClass(t) if clazz.isInstance(t) => println(t) // you could use `t.asInstanceOf[T]`
    case _ => 
  }
}

这篇关于抽象类型模式是未经检查的，因为它被擦除消除的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！