void clearVariants(boolean expected, int start) {
      MyList<Variant> list = expected? variants : unexpected;
      if (start < 0 || start >= list.size()) return;
      for (int i = start, len = list.size(); i < len; i ++) {
        VARIANTS.recycle(list.get(i));
      }
      list.setSize(start);
    }
void clearVariants(boolean expected, int start)