Scala-native: Equality between boxes of different types has wrong semantics

[densh]

object Test {
  def main(args: Array[String]): Unit = {
    val x: Any = 66
    val y: Any = 66.toByte
    println(x == y)
  }
}

This should print true, but prints false at the moment.

[sjrd]

You need to call BoxesRunTime.equals when translating an == primitive in the scalac back-end.

[densh]

Yep, currently we mistakingly just call java.lang.Object.equals instead. It obviously doesn't support cooperative equality between primitive boxes.

[sjrd]

Well in fact, in the case of SN, you could actually change Integer.equals and friends so that they do support cooperative equality. That would help SN with the bad == performance of Scala. But you will have to trade some of the semantics of Object.equals for that.

[densh]

Alternatively, we can also add a new virtual method (e.g. java.lang.Object.==) that behaves like cooperative Scala equality from BoxesRunTime.equals and is overridden for all box types without touching java.lang.Object.equals. Win-win. 👏