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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)
}
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