Scala example source code file (bug2094.scala)

This example Scala source code file (bug2094.scala) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Scala tags/keywords

app, class, knowntype, knowntype, map, map, none, option, some, test, unknownvalue, unknownvalue, value, value

The Scala bug2094.scala source code

object Test extends App {
  // compiles:
  Map[Int, Value](
    0 -> KnownType(classOf[Object]),
    1 -> UnknownValue())

  // does not compile:
  Map(
    0 -> KnownType(classOf[Object]),
    1 -> UnknownValue())

  // Experiment.scala:10: error: type mismatch;
  //  found   : (Int, KnownType)
  //  required: (Int, Product with Value{def getType: Option[java.lang.Class[_$$2]]}) where type _$$2
  //     0 -> KnownType(classOf[Object]),
  //       ^
  // one error found
}
sealed trait Value {
  def getType: Option[Class[_]]
}

case class UnknownValue() extends Value {
  def getType = None
  // compiles if changed to:
  // def getType: Option[Class[_]] = None
}

case class KnownType(typ: Class[_]) extends Value {
  def getType = Some(typ)
}