Which version of scala were you using to test this. Use of tagged types and case classes still does not seem to work (as of 10.2 which I am using) : https://issues.scala-lang.org/browse/SI-5183
Which version of scala were you using to test this. Use of tagged types and case classes still does not seem to work (as of 10.2 which I am using) : https://issues.scala-lang.org/browse/SI-5183