Chisel picked up Scala 3 support in 7.0.0 released last September (https://github.com/chipsalliance/chisel/releases/tag/v7.0.0), right now they cross-compile between Scala 2 and 3 but from what I heard they should eventually move to Scala 3 only to start taking advantage of new features like named tuples (https://docs.scala-lang.org/scala3/reference/other-new-featu...).