return s.val
}

func (s Some[T]) sealedOption() {}

type None struct{}

func (s None) sealedOption() {}

func main() {
	s := returnOption[int](1)
	_ = s.(Some[int])

	s = returnOption[int](0)
	_ = s.(None)

	switch (any)(s).(type) {
	case Some[int]:
		panic("s is a Some[int]")
	case None:
		// ok
	default:
		panic("oops")
	}