Hi folks,  I’m a heavy user of scala-newtype, which allows you to have zero-cost wrappers in Scala 2. For those unfamiliar with it, this is how one can define a newtype:  object data {   @newtype case class Foo(value: String) }  This library is built with macros so it is not available in Scala 3. However, that should not be a problem since we have opaque types.  Current status After trying to migrate a library that uses newtype to cross-compile to Scala 3, I found that opaque types are bit cumbe...