title: New @convention(c) in Swift 2: How can I use it?
body: <p>After migrating to Swift 2, I am getting this issue with an error stating that I should now use @convention(c) (T) -> U. I've tried permutations but so far no luck.</p>
  
  <pre><code>func foo(context: AnyObject?, width: CGFloat) -&gt; Int {
  
  }
  
  let bar = unsafeBitCast(foo, CFunctionPointer&lt;(UnsafeMutablePointer&lt;Void&gt;, Float) -&gt; Int&gt;.self)
  </code></pre>