title: Nullable var inside string template
body: <p>Kotlin has a feature called <a href="https://kotlinlang.org/docs/reference/basic-types.html#string-templates" rel="noreferrer">string templates</a>. Is it safe to use nullable variables inside a string?</p>
  
  <pre><code>override fun onMessageReceived(messageEvent: MessageEvent?) {
      Log.v(TAG, "onMessageReceived: $messageEvent")
  }
  </code></pre>
  
  <p>Will the above code throw <code>NullPointerException</code> if <code>messageEvent</code> is <code>null</code>?  </p>