code: static Matcher sequenceWithFalseIsFalse(Matcher matcher) {
      if (matcher instanceof SeqMatcher) {
        for (Matcher m : matcher.<SeqMatcher>as().matchers()) {
          if (m instanceof FalseMatcher) {
            return FalseMatcher.INSTANCE;
          }
        }
      }
      return matcher;
    }
docs: If a sequence contains an explicit false matcher then the whole sequence will never match
  and can be treated as false.