title: [UIView _forgetDependentConstraint:]: message sent to deallocated instance
body: <p>I tried using NSZobie and all others. Still i face issues. can't able to find where app crashed. Please Help. thanks in advance.</p>
  
  <pre><code> *** -[UIView _forgetDependentConstraint:]: message sent to deallocated instance 0x208e0010
  (lldb) bt
  * thread #1: tid = 0x2503, 0x342b3468 CoreFoundation`___forwarding___ + 192, stop reason = EXC_BREAKPOINT (code=EXC_ARM_B`enter code here`REAKPOINT, subcode=0xdefe)
      frame #0: 0x342b3468 CoreFoundation`___forwarding___ + 192
      frame #1: 0x3420af68 CoreFoundation`__forwarding_prep_0___ + 24
      frame #2: 0x364f24ba UIKit`_updateViewDependenciesForConstraint + 202
      frame #3: 0x364f9a2c UIKit`__72-[UIView(AdditionalLayoutSupport) _removeRelevantConstraintsFromEngine:]_block_invoke_0 + 264
      frame #4: 0x34c65882 Foundation`-[NSISEngine withAutomaticOptimizationDisabled:] + 166
      frame #5: 0x364f98ee UIKit`-[UIView(AdditionalLayoutSupport) _removeRelevantConstraintsFromEngine:] + 94
      frame #6: 0x3629f4a0 UIKit`__UIViewWillBeRemovedFromSuperview + 588
      frame #7: 0x360e7848 UIKit`-[UIView(Hierarchy) removeFromSuperview] + 56
      frame #8: 0x36137f18 UIKit`-[UINavigationTransitionView _cleanupTransition] + 92
      frame #9: 0x360ceab2 UIKit`-[UIViewAnimationState sendDelegateAnimationDidStop:finished:] + 158
      frame #10: 0x361438ee UIKit`-[UIViewAnimationState animationDidStop:finished:] + 50
      frame #11: 0x35e78c00 QuartzCore`CA::Layer::run_animation_callbacks(void*) + 208
      frame #12: 0x3c3f04b6 libdispatch.dylib`_dispatch_client_callout + 22
      frame #13: 0x3c3f51bc libdispatch.dylib`_dispatch_main_queue_callback_4CF$VARIANT$mp + 224
      frame #14: 0x34284f3a CoreFoundation`__CFRunLoopRun + 1290
      frame #15: 0x341f7ebc CoreFoundation`CFRunLoopRunSpecific + 356
      frame #16: 0x341f7d48 CoreFoundation`CFRunLoopRunInMode + 104
      frame #17: 0x37dd02ea GraphicsServices`GSEventRunModal + 74
      frame #18: 0x3610d300 UIKit`UIApplicationMain + 1120
      frame #19: 0x000521de MyApp®`main(argc=1, argv=0x2fdb3cf8) + 162 at main.m:6
      frame #20: 0x3c410b20 libdyld.dylib`start + 4
  </code></pre>