try_finally.scala

//In scalaz 8 IO
IO.fail(new Error("1"))
  .ensuring(IO.fail(new Error("2")))
  .ensuring(IO.fail(new Error("3")))
  .catchAll[E](e4 => IO.sync(println(e4.toString)))

//is (I think) equivalent to this?
try {
  try {
    try {
      throw new Error("1")
    } finally {
      throw new Error("2")
    }
  }
  finally {
    throw new Error("3")
  }
}
catch {
  case e4: Throwable => println(e4.toString)
}

//What do they print?
// the scalaz version will print `Error(1)` - finalizer errors are swallowed
// the try/finally version will print `Error(3)` - original exceptions are swallowed