checkNotNull(sequence);
      return "";
    }

    @Override
    public String replaceFrom(CharSequence sequence, char replacement) {
      char[] array = new char[sequence.length()];
      Arrays.fill(array, replacement);
      return new String(array);
    }

    @Override
    public String replaceFrom(CharSequence sequence, CharSequence replacement) {

      checkNotNull(sequence);
      return "";
    }

    @Override
    public String replaceFrom(CharSequence sequence, char replacement) {
      char[] array = new char[sequence.length()];
      Arrays.fill(array, replacement);
      return new String(array);
    }

    @Override
    public String replaceFrom(CharSequence sequence, CharSequence replacement) {

  }

  public void testGetGenericSuperclass_wildcard_boundIsInterface() {
    assertThat(TypeToken.of(Types.subtypeOf(CharSequence.class)).getGenericSuperclass()).isNull();
    assertEquals(
        new TypeToken<CharSequence[]>() {},
        TypeToken.of(Types.subtypeOf(CharSequence[].class)).getGenericSuperclass());
  }

  public <T> void testGetGenericInterfaces_typeVariable_unbounded() {

  }

  public void testGetGenericSuperclass_wildcard_boundIsInterface() {
    assertThat(TypeToken.of(Types.subtypeOf(CharSequence.class)).getGenericSuperclass()).isNull();
    assertEquals(
        new TypeToken<CharSequence[]>() {},
        TypeToken.of(Types.subtypeOf(CharSequence[].class)).getGenericSuperclass());
  }

  public <T> void testGetGenericInterfaces_typeVariable_unbounded() {

      Type subtypeParam = getCovariantTypeResolver().resolveType(typeVars[i]);
      // If 'supertype' is "List<? extends CharSequence>"
      // and 'this' is StringArrayList,
      // First step is to figure out StringArrayList "is-a" List<E> where <E> = String.
      // String is then matched against <? extends CharSequence>, the supertypeArgs[0].
      if (!of(subtypeParam).is(supertypeArgs[i], typeVars[i])) {
        return false;
      }