bug414.scala:1: warning: case classes without a parameter list have been deprecated;
use either case objects or case classes with `()' as parameter list.
case class Empty[a] extends IntMap[a];
                    ^
bug414.scala:5: error: pattern type is incompatible with expected type;
 found   : object Empty
 required: IntMap[a]
                case Empty =>
                     ^
bug414.scala:7: error: type mismatch;
 found   : Unit
 required: a
                case _ =>
                       ^
one warning found
two errors found