Why do I get 'cps-transformed unexpectedly' message on Scala continuations

Question

So I have the following code (doing exercise 4 of that tutorial):

import scala.util.continuations._
object Main {
  def times(lst: List[Int]): Int@cps[Int] = lst match {
    case Nil => 1
    case 0 :: rest => shift{(_: Int=>Int) => 0 } * times(rest)
    case first :: rest => first * times(rest)
  }
  def main(args: Array[String]) {
    println(reset{times(List(0 to 1000: _*))})
  }
}

I'm compiling with scala 2.10.0 and I got the following warning:

CWSO.scala:3: warning: expression matchEnd9(x: Int){
  x
} is cps-transformed unexpectedly
  def times(lst: List[Int]): Int@cps[Int] = lst match {
                                            ^
one warning found

Is there something wrong in the way I wrote that code? What should I do to avoid the warning? The code seems to be doing the correct thing (multiplies numbers and aborts early when 0 is the first element).

Answer 1

This smells like a bug, and was reported as such: https://issues.scala-lang.org/browse/SI-6817