@Override
      public boolean add(@Nullable HighlightInfo info) {
        boolean added;
        synchronized (this) {
          added = super.add(info);
        }
        if (info != null && added && info.getSeverity() == HighlightSeverity.ERROR) {
          myHasErrorSeverity = true;
        }
        return added;
      }
@Override
      public boolean add(@Nullable HighlightInfo info)