Thank you for the implementation proposals. I myself would have reimplemented it using an array internally. But if java.util.EnumMap can be used with a few little-known tricks, then that’s easier.
However, this is not what my post was really about (I would have posted on users.scala-lang.org, otherwise). I was asking about plans to add it to the standard library, as it seems to me that enums are incomplete without it.
I would expect most Scala users to default to more ugly code, or reimplement a worse version of EnumMap, rather than discover how to get java.util.EnumMap to work for their Scala enums.