fun box(): String {
  val map: MutableMap<Fun, String> = mutableMapOf<Fun, String>()
  val fn: Fun = local fun <anonymous>(it: @FlexibleNullability String?): @FlexibleNullability String? {
    return TODO()
  }
 /*-> Fun */
  return map.computeIfAbsent(p0 = fn, p1 = local fun <anonymous>(it: @EnhancedNullability Fun): @EnhancedNullability String {
    return "OK"
  }
 /*as Function1<@EnhancedNullability Any?, @EnhancedNullability String> */ /*-> @EnhancedNullability Function<Any?, @EnhancedNullability String> */) /*!! String */
}