I got this error defining the function

object test {
  val f:AnyVal => String = {
      case 10.0 => "10.0"
      case _: Double => "Double"
      case _: Int => "Int"
      case _: Byte => "Byte"
      case _ => "anything else"
}

 -> Incomplete statements not supported yet, sorry, you’ll have to retype.

However, in REPL it worked just fine.

repat@laptop:~$ scala
Welcome to Scala version 2.10.3 (OpenJDK 64-Bit Server VM, Java 1.6.0_27).
Type in expressions to have them evaluated.
Type :help for more information.

scala>   val f:AnyVal => String = {
     |       case 10.0 => "10.0"
     |       case _: Double => "Double"
     |       case _: Int => "Int"
     |       case _: Byte => "Byte"
     |       case _ => "anything else"
     |   }
f: AnyVal => String = 

scala>

So aparrently the error is in Eclipse. I use the version 3.7.2. Have you tried turning it off and on again? 😉