* @since 19.0 (since 1.0 as constant {@code INVISIBLE})
   */
  @Deprecated
  public static CharMatcher invisible() {
    return Invisible.INSTANCE;
  }

  /**
   * Determines whether a character is single-width (not double-width). When in doubt, this matcher
   * errs on the side of returning {@code false} (that is, it tends to assume a character is
   * double-width).
   *

    doTestSetBits(inRange('n', 'q'));
    doTestSetBits(forPredicate(Predicates.equalTo('c')));
    doTestSetBits(CharMatcher.ascii());
    doTestSetBits(CharMatcher.digit());
    doTestSetBits(CharMatcher.invisible());
    doTestSetBits(CharMatcher.whitespace());
    doTestSetBits(inRange('A', 'Z').and(inRange('F', 'K').negate()));
  }

  @GwtIncompatible // java.util.BitSet
  private void doTestSetBits(CharMatcher matcher) {

    doTestSetBits(inRange('n', 'q'));
    doTestSetBits(forPredicate(Predicates.equalTo('c')));
    doTestSetBits(CharMatcher.ascii());
    doTestSetBits(CharMatcher.digit());
    doTestSetBits(CharMatcher.invisible());
    doTestSetBits(CharMatcher.whitespace());
    doTestSetBits(inRange('A', 'Z').and(inRange('F', 'K').negate()));
  }

  @GwtIncompatible // java.util.BitSet
  private void doTestSetBits(CharMatcher matcher) {