Scala lost guarded exhaustiveness checks at 2.10.x... very annoying

gistfile1.txt

mark@mark-pc2:~/tmp/patterns$ cat Test.scala
sealed trait Foo
case object A extends Foo
case object B extends Foo

object Test {
  def f(foo: Foo) {
    foo match {
      case A if true =>
        println("A")
      case B =>
        println("B")
    }
  }
}
mark@mark-pc2:~/tmp/patterns$ ~/scala-2.8.0.final/bin/scalac ./Test.scala
./Test.scala:7: warning: match is not exhaustive!
missing combination              A

    foo match {
    ^
one warning found
mark@mark-pc2:~/tmp/patterns$ ~/scala-2.9.3/bin/scalac ./Test.scala
./Test.scala:7: warning: match is not exhaustive!
missing combination              A

    foo match {
    ^
one warning found
mark@mark-pc2:~/tmp/patterns$ ~/scala-2.10.5/bin/scalac ./Test.scala
mark@mark-pc2:~/tmp/patterns$ ~/scala-2.11.6/bin/scalac ./Test.scala
mark@mark-pc2:~/tmp/patterns$