code: @Override
      public void setIndex(boolean b)
      {
          if (b)
          {
              assert safe == null;
              safe = type;
              type = Typ.Int;
          }
          else
          {
              assert type.getKind() == TypeKind.INT;
              assert safe != null;
              type = safe;
              safe = null;
          }
      }
docs: Set index parsing mode. In true mode we are parsing inside bracket where
  index type must be int.
  @param b