title: EXC_BAD_ACCESS KERN_INVALID_ADDRESS crash
body: <p>My app has been running fine in debugging mode through Xcode, but whenever it's downloaded through TestFlight, it crashes with this error: <code>EXC_BAD_ACCESS KERN_INVALID_ADDRESS 0x000200013f7b9e78</code>. </p>
  
  <p>It's crashing at this line. I see <code>specialized Array.withUnsafeMutableBufferPoint</code> in this stack trace that it's probably related to. </p>
  
  <pre><code>self.array.sortInPlace. {
                  (($0 as Dictionary&lt;String, AnyObject&gt;)["time"] as? String) &gt; (($1 as Dictionary&lt;String, AnyObject&gt;)["time"] as? String)
              }
  </code></pre>
  
  <p>In Swift 1.3 I was using <code>sort</code>, and now in Swift 2 I'm using <code>sortInPlace</code>. Not sure if this makes a difference, but I do know that the result of <code>sort</code> isn't called because it's immutable. </p>
  
  <pre><code>Thread : Crashed: com.apple.main-thread
      0  libswiftCore.dylib             4302688056 _swift_retain_(swift::HeapObject*) + 8
      1  App                          4295962040 specialized LiveFeedViewController.(viewDidLoad(LiveFeedViewController) -&gt; () -&gt; ()).(closure #3).(closure #1) (LiveFeedViewController.swift)
      2  App                          4295785356 specialized thunk (LiveFeedViewController.swift)
      3  App                          4295953880 specialized _siftDown&lt;A where ...&gt; (inout A, A.Index, Range&lt;A.Index&gt;, inout (A.Generator.Element, A.Generator.Element) -&gt; Bool) -&gt; () (LiveFeedViewController.swift)
      4  App                          4295952448 specialized _heapSort&lt;A where ...&gt; (inout A, Range&lt;A.Index&gt;, inout (A.Generator.Element, A.Generator.Element) -&gt; Bool) -&gt; () (LiveFeedViewController.swift)
      5  App                          4295938144 specialized _introSortImpl&lt;A where ...&gt; (inout A, Range&lt;A.Index&gt;, inout (A.Generator.Element, A.Generator.Element) -&gt; Bool, Int) -&gt; () (LiveFeedViewController.swift)
      6  App                          4295938120 specialized _introSortImpl&lt;A where ...&gt; (inout A, Range&lt;A.Index&gt;, inout (A.Generator.Element, A.Generator.Element) -&gt; Bool, Int) -&gt; () (LiveFeedViewController.swift)
      7  App                          4295938120 specialized _introSortImpl&lt;A where ...&gt; (inout A, Range&lt;A.Index&gt;, inout (A.Generator.Element, A.Generator.Element) -&gt; Bool, Int) -&gt; () (LiveFeedViewController.swift)
      8  App                          4295938120 specialized _introSortImpl&lt;A where ...&gt; (inout A, Range&lt;A.Index&gt;, inout (A.Generator.Element, A.Generator.Element) -&gt; Bool, Int) -&gt; () (LiveFeedViewController.swift)
      9  App                          4295938120 specialized _introSortImpl&lt;A where ...&gt; (inout A, Range&lt;A.Index&gt;, inout (A.Generator.Element, A.Generator.Element) -&gt; Bool, Int) -&gt; () (LiveFeedViewController.swift)
      10 App                          4295938120 specialized _introSortImpl&lt;A where ...&gt; (inout A, Range&lt;A.Index&gt;, inout (A.Generator.Element, A.Generator.Element) -&gt; Bool, Int) -&gt; () (LiveFeedViewController.swift)
      11 App                          4295938120 specialized _introSortImpl&lt;A where ...&gt; (inout A, Range&lt;A.Index&gt;, inout (A.Generator.Element, A.Generator.Element) -&gt; Bool, Int) -&gt; () (LiveFeedViewController.swift)
      12 App                          4295938120 specialized _introSortImpl&lt;A where ...&gt; (inout A, Range&lt;A.Index&gt;, inout (A.Generator.Element, A.Generator.Element) -&gt; Bool, Int) -&gt; () (LiveFeedViewController.swift)
      13 App                          4295938120 specialized _introSortImpl&lt;A where ...&gt; (inout A, Range&lt;A.Index&gt;, inout (A.Generator.Element, A.Generator.Element) -&gt; Bool, Int) -&gt; () (LiveFeedViewController.swift)
      14 App                          4295938120 specialized _introSortImpl&lt;A where ...&gt; (inout A, Range&lt;A.Index&gt;, inout (A.Generator.Element, A.Generator.Element) -&gt; Bool, Int) -&gt; () (LiveFeedViewController.swift)
      15 App                          4295960640 specialized specialized MutableCollectionType&lt;A where ...&gt;.sortInPlace&lt;A where ...&gt;((A.Generator.Element, A.Generator.Element) -&gt; Bool) -&gt; () (LiveFeedViewController.swift)
      16 App                          4295730388 _TPA__TTSg5GSaGVSs10DictionarySSPSs9AnyObject___GSaGS_SSPS0____Ss21MutableCollectionTypeSs_GVSs17IndexingGeneratorGSaGS_SSPS0_____GS2_GSaGS_SSPS0_____Ss13GeneratorTypeSs_GS_SSPS0____SiSiSs21RandomAccessIndexTypeSs_SiSiSs18_SignedIntegerTypeSs_SiSiSs33_BuiltinIntegerLiteralConvertibleSs_SiSiSs16SignedNumberTypeSs_SiSiS6_Ss_Si_GVSs10ArraySliceGS_SSPS0____GS8_GS_SSPS0____Ss9IndexableSsGS8_GS_SSPS0____Ss12SequenceTypeSs_GS2_GS8_GS_SSPS0_____GS2_GS8_GS_SSPS0_____S3_Ss_GS_SSPS0____SiSiSs16ForwardIndexTypeSs_SiSiS5_Ss_SiSiS6_Ss_Si_GS8_GS_SSPS0_____GS_SSPS0____GS_SSPS0______TFFeRq_Ss21MutableCollectionTypeqq_Ss16MutableIndexable5IndexSs21RandomAccessIndexType_SsS_11sortInPlaceuRq_S_qq_S0_5IndexS1__FRq_FFTqqq_Ss14CollectionType9GeneratorSs13GeneratorType7Elementqqq_S2_9GeneratorS3_7Element_SbT_U_FTGVSs20UnsafeMutablePointerQQQPS_9Generator7Element_Si_T_ (LiveFeedViewController.swift)
      17 App                          4295730548 _TPA__TTSg5GSaGVSs10DictionarySSPSs9AnyObject___GSaGS_SSPS0____Ss21MutableCollectionTypeSs_GVSs17IndexingGeneratorGSaGS_SSPS0_____GS2_GSaGS_SSPS0_____Ss13GeneratorTypeSs_GS_SSPS0____SiSiSs21RandomAccessIndexTypeSs_SiSiSs18_SignedIntegerTypeSs_SiSiSs33_BuiltinIntegerLiteralConvertibleSs_SiSiSs16SignedNumberTypeSs_SiSiS6_Ss_Si_GVSs10ArraySliceGS_SSPS0____GS8_GS_SSPS0____Ss9IndexableSsGS8_GS_SSPS0____Ss12SequenceTypeSs_GS2_GS8_GS_SSPS0_____GS2_GS8_GS_SSPS0_____S3_Ss_GS_SSPS0____SiSiSs16ForwardIndexTypeSs_SiSiS5_Ss_SiSiS6_Ss_Si_GS8_GS_SSPS0_____GS_SSPS0____GS_SSPS0______TTRGRq_Ss21MutableCollectionTypeqq_Ss16MutableIndexable5IndexSs21RandomAccessIndexType_XFo_dGVSs20UnsafeMutablePointerqqq_Ss14CollectionType9GeneratorSs13GeneratorType7Element_dSi_dT_zoPSs9ErrorType__XFo_dGS2_qqq_S3_9GeneratorS4_7Element_dSi_iT_zoPS5___ (LiveFeedViewController.swift)
      18 App                          4295730716 _TPA__TTSg5GVSs10DictionarySSPSs9AnyObject___T____TFFSa42_withUnsafeMutableBufferPointerIfSupportedu__rFRGSaq__FzFzTGVSs20UnsafeMutablePointerq__Si_qd__GSqqd___U_FzRGVSs26UnsafeMutableBufferPointerQd___Q_ (LiveFeedViewController.swift)
      19 App                          4295954668 specialized Array.withUnsafeMutableBufferPointer&lt;A&gt;&lt;B&gt;((inout UnsafeMutableBufferPointer&lt;A&gt;) throws -&gt; B) throws -&gt; B (LiveFeedViewController.swift)
      20 App                          4295959880 specialized specialized MutableCollectionType&lt;A where ...&gt;.sortInPlace&lt;A where ...&gt;((A.Generator.Element, A.Generator.Element) -&gt; Bool) -&gt; () (LiveFeedViewController.swift)
      21 App                          4295895596 LiveFeedViewController.(viewDidLoad(LiveFeedViewController) -&gt; () -&gt; ()).(closure #3) (LiveFeedViewController.swift:1862)
      22 libdispatch.dylib              6875551464 _dispatch_call_block_and_release + 24
      23 libdispatch.dylib              6875551400 _dispatch_client_callout + 16
      24 libdispatch.dylib              6875573680 _dispatch_main_queue_callback_4CF + 1844
      25 CoreFoundation                 6518931960 __CFRUNLOOP_IS_SERVICING_THE_MAIN_DISPATCH_QUEUE__ + 12
      26 CoreFoundation                 6518923360 __CFRunLoopRun + 1628
      27 CoreFoundation                 6518066336 CFRunLoopRunSpecific + 384
      28 GraphicsServices               6704955528 GSEventRunModal + 180
      29 UIKit                          6609391612 UIApplicationMain + 204
      30 App                          4296344512 main (AppDelegate.swift:23)
      31 libdyld.dylib                  6875752632 start + 4
  </code></pre>
  
  <p>UPDATE:</p>
  
  <p>This is all in Swift 2, and the array is an array of dictionaries, declared as <code>var array = [[String:AnyObject]]()</code>. It's populated by appending a series of dictionaries, like this.</p>
  
  <pre><code>self.dict["foo"] = 0
  self.dict["bar"] = "dog"
  self.array.append(self.dict)
  </code></pre>
  
  <p>My concern is that its within a <code>dispatch_group_notify</code>; it's waiting on series of <code>dispatch_group_leave</code>s. Could that have something to do with it? That looks like this:</p>
  
  <pre><code>dispatch_group_notify(group, queue) { () -&gt; Void in
  
        self.array.sortInPlace {
            (($0["foo"] as? Int) &gt; (($1 )["foo"] as? Int))
        }
  }
  </code></pre>