class Test
{
    sealed interface MyBoolean
    {
        record True() implements MyBoolean {}
        record False() implements MyBoolean {}
    }

    String describe(MyBoolean value)
    {
        final String description;

        switch (value) {
            case MyBoolean.True t -> description = "It's True";
            case MyBoolean.False f -> description = "It's False";
            //default -> throw new IllegalStateException("Cannot happen javac!");
        }

        return description;
    }
}