title: computed property must have an explicit type while using didSet
body: <pre><code>var number = 0 {
          didSet {
              self.updateScore()
        }
  }
  </code></pre>
  
  <p>After writing this code  a failure appears: computed property must have an explicit type. I believe it`s a problem with my version of Xcode (6.2), cause at my friends computer compiles perfectly. What should I change, so that it works on mine?</p>