title: NSNumber acting as an optional even though it not declared as one
body: <p>I have a number I am storing inside a swift dictionary. I am using NSNumber since I must serialize to JSON. I'm confused as to why the 5th line below down not work and the 6th does. The <code>currentCt</code> seems to think it is an optional, however, on line 1 it is not declared as an optional a in <code>Dictionary&lt;String, NSNumber&gt;()</code> Any thoughts as to why?</p>
  
  <p>Also, I am not sure why bridging does not allow the Int and NSNumber to be automatically added and I must resort to using Int(currentCt!) . Again, any thoughts are much appreciated.</p>
  
  <pre><code>var activeMinDic = Dictionary&lt;String, NSNumber&gt;()
  activeMinDic["1"] = 5
  var currentCt = activeMinDic[String(1)]
  activeMinDic[String(1)] = 1 + 1 // works fine
  activeMinDic[String(1)] = 1 + currentCt // does not work
  activeMinDic[String(1)] = 1 + Int(currentCt!) // works
  </code></pre>