code: func (sc *StatementContext) HandleOverflow(err error, warnErr error) error {
  	if err == nil {
  		return nil
  	}
  
  	if sc.OverflowAsWarning {
  		sc.AppendWarning(warnErr)
  		return nil
  	}
  	return err
  }
docs: // HandleOverflow treats ErrOverflow as warnings or returns the error based on the StmtCtx.OverflowAsWarning state.