title: Check empty struct that have array fields
body: <p>I have a nested (not embedded) struct for which some of field types are arrays.</p>
  
  <p>How can I check if an instance of this struct is empty? (not using iteration!!)</p>
  
  <p>Note that there can't use <code>StructIns == (Struct{})</code> or by an empty instance! This code have this error:</p>
  
  <p><code>invalid operation: user == model.User literal (struct containing model.Configs cannot be compared)</code></p>
  
  <p>user.Configs.TspConfigs:</p>
  
  <pre><code>type TspConfigs struct {
      Flights     []Flights   `form:"flights" json:"flights"`
      Tours       []Tours     `form:"tours" json:"tours"`
      Insurances  []Insurances`form:"insurances" json:"insurances"`
      Hotels      []Hotels    `form:"hotels" json:"hotels"`
  }
  </code></pre>