title: Why Obj-C property default ownership "assign" instead of "strong"
body: <p>I'm adding Swift classes to an old project. It went well, until I tried adding a property to the Swift class. The generated header doesn't compile.</p>
  
  <p><img src="https://i.stack.imgur.com/BeVYP.png" alt="enter image description here"></p>
  
  <p>I think the problem is, in the generated code, Swift omitted <code>strong</code> ownership and only declared it as <code>nonatomic</code>. This should normally be enough, because @property should default to <code>strong</code> ownership, right?  </p>
  
  <p>So basically these are equivalent:</p>
  
  <ul>
  <li><code>@property (nonatomic) NSDate *aDate;</code></li>
  <li><code>@property (nonatomic, strong) NSDate *aDate;</code></li>
  </ul>
  
  <p>But, in my case, it seems like it is defaulting to <code>assign</code> instead of <code>strong</code>, according to the compiler message. </p>
  
  <p>I'm using Xcode 6 GM, and the project has ARC turned on.</p>
  
  <p>Any idea why it is not defaulting to <code>strong</code>? Can I change this somehow? </p>