title: Why add "()" after closure body in Golang?
body: <p>I'm reading <code>The Go Programming Language Specifications</code> and found myself not truly understand with "()" after closure body:</p>
  
  <p>In <code>Function literals</code>:</p>
  
  <blockquote>
    <p>func(ch chan int) { ch &lt;- ACK }<strong>(replyChan)</strong>`</p>
  </blockquote>
  
  <p>In <code>Defer statements</code>'s example:</p>
  
  <pre><code>// f returns 1
  func f() (result int) {
      defer func() {
          result++
      }() // why and how?
      return 0
  }
  </code></pre>
  
  <p>I'm not clear about the reason to add &amp; usage of "()" after closure body, hope someone can explain this clearly.</p>