title: Cannot call value of non-function type 'Closure Name'
body: <p>I define a Closure named <code>touchBlock</code>, and user it in <code>override func touchesEnded</code>, then I get an error :</p>
  
  <blockquote>
    <p>Cannot call value of non-function type '((ELControl, UIEvent, UIEvent)
    -> Void?)?</p>
  </blockquote>
  
  <p>Here is my code:</p>
  
  <pre><code>var touchBlock: ((_ view: ELControl, _ touches: UIEvent, _ event: UIEvent) -&gt; Void?)?    
  override func touchesEnded(_ touches: Set&lt;UITouch&gt;, with event: UIEvent?) {
  
      if self.touchBlock != nil {
  
          self.touchBlock(nil, touches, event)
      } else {
  
          super.touchesEnded(touches, with: event)
      }
  }
  </code></pre>
  
  <p>Please help me to fix it.</p>