def m1(def x) {
  if (x instanceof CharSequence) {
    x = Integer.valueOf(x) // typeof(x) == Integer
  }
  x // typeof(x) == LUB(Object,Integer)
}

def m1(def x) {
  if (predicate()) {
    x = ''
  } else {
    x = new StringBuffer()
  }
  x // typeof(x) == LUB(String,StringBuffer)
}