title: Call has possible formatting directive
body: <p>When I run this code</p>
  <pre><code>package main
  import (&quot;fmt&quot;)
  func main() {
      i := 5
      fmt.Println(&quot;Hello, playground %d&quot;,i)
  }
  </code></pre>
  <p>(<a href="https://play.golang.org/p/0Dhuhi8trQK" rel="noreferrer">playground link</a>)</p>
  <p>I get the following warning:</p>
  <pre><code>prog.go:5: Println call has possible formatting directive %d
  Go vet exited.
  </code></pre>
  <p>What is a proper way to do this?</p>