Improve opaque types

[SethTisue]

@LPTK

In Scala 2, the following code will not box any of the integers, AFAIK (someone correct me if I’m wrong):

You’re not wrong. If you javap -c it you’ll see that Scala 2 uses Tuple2$mcII$sp (specialized) throughout, rather than an ordinary Tuple2, to avoid boxing the Ints. Whereas Scala 3 boxes them.