Infinite loop in interpreter

[DarkDimius]

pasting http://scalapuzzlers.com/#pzzlr-034

val ints = List(1, 2, 3)
val accumulator: List[Int] = Nil

val leftReversed = (ints foldLeft accumulator) { (acc, elem) => elem :: acc }
val rightReversed = (ints foldRight accumulator) { (elem, acc) => acc :+ elem }
println(leftReversed)
println(rightReversed)

// ...and back
println((leftReversed /: accumulator) { (acc, elem) => elem :: acc })
println((rightReversed :\ accumulator) { (elem, acc) => acc :+ elem })

into interpreter sends it into infinite look after the // ...and back comment.
Additionally, we disable control-c, there's no easy way to kill it.