title: How to add @noescape annotation to optional closure
body: <p>My function has this signature:</p>
  
  <pre><code>func foo(bar: String, baz: ((String) -&gt; ())? = nil)
  </code></pre>
  
  <p>And now I want to make unecessary to escape <code>self</code> inside the given closure.
  But when I try this:</p>
  
  <pre><code>func foo(bar: String, @noescape baz: ((String) -&gt; ())? = nil)
  </code></pre>
  
  <p>The compiler complains:</p>
  
  <pre><code>@noescape may only be applied to parameters of function type
  </code></pre>
  
  <p>Is it possible to use it in optional parameters?</p>