assertEquals(-1, matcher.indexIn(s));
    assertEquals(-1, matcher.indexIn(s, 0));
    assertEquals(-1, matcher.indexIn(s, 1));
    assertEquals(-1, matcher.indexIn(s, s.length()));
    try {
      matcher.indexIn(s, s.length() + 1);
      fail();
    } catch (IndexOutOfBoundsException expected) {
    }
    try {
      matcher.indexIn(s, -1);
      fail();

    return new Splitter(
        (splitter, toSplit) ->
            new SplittingIterator(splitter, toSplit) {
              @Override
              int separatorStart(int start) {
                return separatorMatcher.indexIn(toSplit, start);
              }

              @Override
              int separatorEnd(int separatorPosition) {
                return separatorPosition + 1;
              }
            });
  }

    return new Splitter(
        (splitter, toSplit) ->
            new SplittingIterator(splitter, toSplit) {
              @Override
              int separatorStart(int start) {
                return separatorMatcher.indexIn(toSplit, start);
              }

              @Override
              int separatorEnd(int separatorPosition) {
                return separatorPosition + 1;
              }
            });
  }

    }

    @CanIgnoreReturnValue
    String consumeTokenIfPresent(CharMatcher matcher) {
      checkState(hasMore());
      int startPosition = position;
      position = matcher.negate().indexIn(input, startPosition);
      return hasMore() ? input.substring(startPosition, position) : input.substring(startPosition);
    }

    String consumeToken(CharMatcher matcher) {
      int startPosition = position;