fun test1(x: Int): Int {
  return x.unaryMinus()
}

fun test2(): Int {
  return -42
}

fun test3(x: Int): Int {
  return x.unaryPlus()
}

fun test4(): Int {
  return 42
}

fun test5(x: Boolean): Boolean {
  return x.not()
}

fun test6(): Boolean {
  return true.not()
}