diff --git a/AsyncDisplayKit/ASControlNode.mm b/AsyncDisplayKit/ASControlNode.mm
index 34333ea0dd..29b0b57da2 100644
--- a/AsyncDisplayKit/ASControlNode.mm
+++ b/AsyncDisplayKit/ASControlNode.mm
@@ -286,7 +286,9 @@ void _ASEnumerateControlEventsIncludedInMaskWithBlock(ASControlNodeEvent mask, v
       {
         // Create the dispatch table for this event.
         eventDispatchTable = [NSMapTable weakToStrongObjectsMapTable];
-        _controlEventDispatchTable[eventKey] = eventDispatchTable;
+        if (eventKey) {
+          [_controlEventDispatchTable setObject:eventDispatchTable forKey:eventKey];
+        }
       }
 
       // Have we seen this target before for this event?
@@ -442,9 +444,11 @@ id<NSCopying> _ASControlNodeEventKeyForControlEvent(ASControlNodeEvent controlEv
 
 void _ASEnumerateControlEventsIncludedInMaskWithBlock(ASControlNodeEvent mask, void (^block)(ASControlNodeEvent anEvent))
 {
+  if (block == nil) {
+    return;
+  }
   // Start with our first event (touch down) and work our way up to the last event (touch cancel)
-  for (ASControlNodeEvent thisEvent = ASControlNodeEventTouchDown; thisEvent <= ASControlNodeEventTouchCancel; thisEvent <<= 1)
-  {
+  for (ASControlNodeEvent thisEvent = ASControlNodeEventTouchDown; thisEvent <= ASControlNodeEventTouchCancel; thisEvent <<= 1){
     // If it's included in the mask, invoke the block.
     if ((mask & thisEvent) == thisEvent)
       block(thisEvent);
diff --git a/AsyncDisplayKit/ASRunLoopQueue.mm b/AsyncDisplayKit/ASRunLoopQueue.mm
index 693f01dc75..44621b667d 100644
--- a/AsyncDisplayKit/ASRunLoopQueue.mm
+++ b/AsyncDisplayKit/ASRunLoopQueue.mm
@@ -59,13 +59,15 @@ static void runLoopSourceCallback(void *info) {
     // It is not guaranteed that the runloop will turn if it has no scheduled work, and this causes processing of
     // the queue to stop. Attaching a custom loop source to the run loop and signal it if new work needs to be done
     CFRunLoopSourceContext *runLoopSourceContext = (CFRunLoopSourceContext *)calloc(1, sizeof(CFRunLoopSourceContext));
-    runLoopSourceContext->perform = runLoopSourceCallback;
+    if (runLoopSourceContext) {
+      runLoopSourceContext->perform = runLoopSourceCallback;
 #if ASRunLoopQueueLoggingEnabled
-    runLoopSourceContext->info = (__bridge void *)self;
+      runLoopSourceContext->info = (__bridge void *)self;
 #endif
-    _runLoopSource = CFRunLoopSourceCreate(NULL, 0, runLoopSourceContext);
-    CFRunLoopAddSource(runloop, _runLoopSource, kCFRunLoopCommonModes);
-    free(runLoopSourceContext);
+      _runLoopSource = CFRunLoopSourceCreate(NULL, 0, runLoopSourceContext);
+      CFRunLoopAddSource(runloop, _runLoopSource, kCFRunLoopCommonModes);
+      free(runLoopSourceContext);
+    }
 
 #if ASRunLoopQueueLoggingEnabled
     _runloopQueueLoggingTimer = [NSTimer timerWithTimeInterval:1.0 target:self selector:@selector(checkRunLoop) userInfo:nil repeats:YES];
diff --git a/AsyncDisplayKit/ASTableView.mm b/AsyncDisplayKit/ASTableView.mm
index 80bf807308..8fdb55eb44 100644
--- a/AsyncDisplayKit/ASTableView.mm
+++ b/AsyncDisplayKit/ASTableView.mm
@@ -606,16 +606,18 @@ static NSString * const kCellReuseIdentifier = @"_ASTableViewCell";
   cell.delegate = self;
 
   ASCellNode *node = [_dataController nodeAtIndexPath:indexPath];
-  [_rangeController configureContentView:cell.contentView forCellNode:node];
+  if (node) {
+    [_rangeController configureContentView:cell.contentView forCellNode:node];
 
-  cell.node = node;
-  cell.backgroundColor = node.backgroundColor;
-  cell.selectionStyle = node.selectionStyle;
+    cell.node = node;
+    cell.backgroundColor = node.backgroundColor;
+    cell.selectionStyle = node.selectionStyle;
 
-  // the following ensures that we clip the entire cell to it's bounds if node.clipsToBounds is set (the default)
-  // This is actually a workaround for a bug we are seeing in some rare cases (selected background view
-  // overlaps other cells if size of ASCellNode has changed.)
-  cell.clipsToBounds = node.clipsToBounds;
+    // the following ensures that we clip the entire cell to it's bounds if node.clipsToBounds is set (the default)
+    // This is actually a workaround for a bug we are seeing in some rare cases (selected background view
+    // overlaps other cells if size of ASCellNode has changed.)
+    cell.clipsToBounds = node.clipsToBounds;
+  }
 
   return cell;
 }
diff --git a/AsyncDisplayKit/ASVideoPlayerNode.mm b/AsyncDisplayKit/ASVideoPlayerNode.mm
index 7d1dc889d9..0099dd34fe 100644
--- a/AsyncDisplayKit/ASVideoPlayerNode.mm
+++ b/AsyncDisplayKit/ASVideoPlayerNode.mm
@@ -379,19 +379,19 @@ static void *ASVideoPlayerNodeContext = &ASVideoPlayerNodeContext;
       slider.maximumValue = 1.0;
 
       if (_delegateFlags.delegateScrubberMinimumTrackTintColor) {
-        slider.minimumTrackTintColor  = [_delegate videoPlayerNodeScrubberMinimumTrackTint:strongSelf];
+        slider.minimumTrackTintColor  = [strongSelf.delegate videoPlayerNodeScrubberMinimumTrackTint:strongSelf];
       }
 
       if (_delegateFlags.delegateScrubberMaximumTrackTintColor) {
-        slider.maximumTrackTintColor  = [_delegate videoPlayerNodeScrubberMaximumTrackTint:strongSelf];
+        slider.maximumTrackTintColor  = [strongSelf.delegate videoPlayerNodeScrubberMaximumTrackTint:strongSelf];
       }
 
       if (_delegateFlags.delegateScrubberThumbTintColor) {
-        slider.thumbTintColor  = [_delegate videoPlayerNodeScrubberThumbTint:strongSelf];
+        slider.thumbTintColor  = [strongSelf.delegate videoPlayerNodeScrubberThumbTint:strongSelf];
       }
 
       if (_delegateFlags.delegateScrubberThumbImage) {
-        UIImage *thumbImage = [_delegate videoPlayerNodeScrubberThumbImage:strongSelf];
+        UIImage *thumbImage = [strongSelf.delegate videoPlayerNodeScrubberThumbImage:strongSelf];
         [slider setThumbImage:thumbImage forState:UIControlStateNormal];
       }
 
diff --git a/AsyncDisplayKit/Details/ASDataController.mm b/AsyncDisplayKit/Details/ASDataController.mm
index 76c8b723de..40c4af1abf 100644
--- a/AsyncDisplayKit/Details/ASDataController.mm
+++ b/AsyncDisplayKit/Details/ASDataController.mm
@@ -560,6 +560,10 @@ NSString * const ASDataControllerRowNodeKind = @"_ASDataControllerRowNodeKind";
     return;
   }
   
+  if (block == nil) {
+    return;
+  }
+  
   // If we have never performed a reload, there is no value in executing edit operations as the initial
   // reload will directly re-query the latest state of the datasource - so completely skip the block in this case.
   if (_batchUpdateCounter == 0) {
diff --git a/AsyncDisplayKit/Details/NSIndexSet+ASHelpers.m b/AsyncDisplayKit/Details/NSIndexSet+ASHelpers.m
index f05acafa5f..15a4e9ec39 100644
--- a/AsyncDisplayKit/Details/NSIndexSet+ASHelpers.m
+++ b/AsyncDisplayKit/Details/NSIndexSet+ASHelpers.m
@@ -68,9 +68,9 @@
   NSMutableString *result = [NSMutableString stringWithString:@"{ "];
   [self enumerateRangesUsingBlock:^(NSRange range, BOOL * _Nonnull stop) {
     if (range.length == 1) {
-      [result appendFormat:@"%zu ", range.location];
+      [result appendFormat:@"%zu ", (unsigned long)range.location];
     } else {
-      [result appendFormat:@"%zu-%zu ", range.location, NSMaxRange(range) - 1];
+      [result appendFormat:@"%zu-%lu ", (unsigned long)range.location, NSMaxRange(range) - 1];
     }
   }];
   [result appendString:@"}"];
diff --git a/AsyncDisplayKit/Private/ASInternalHelpers.mm b/AsyncDisplayKit/Private/ASInternalHelpers.mm
index 94042053d7..dbe7f16795 100644
--- a/AsyncDisplayKit/Private/ASInternalHelpers.mm
+++ b/AsyncDisplayKit/Private/ASInternalHelpers.mm
@@ -34,6 +34,9 @@ BOOL ASSubclassOverridesClassSelector(Class superclass, Class subclass, SEL sele
 
 void ASPerformBlockOnMainThread(void (^block)())
 {
+  if (block == nil){
+    return;
+  }
   if (ASDisplayNodeThreadIsMain()) {
     block();
   } else {
@@ -43,6 +46,9 @@ void ASPerformBlockOnMainThread(void (^block)())
 
 void ASPerformBlockOnBackgroundThread(void (^block)())
 {
+  if (block == nil){
+    return;
+  }
   if (ASDisplayNodeThreadIsMain()) {
     dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), block);
   } else {
diff --git a/AsyncDisplayKit/Private/ASMultidimensionalArrayUtils.mm b/AsyncDisplayKit/Private/ASMultidimensionalArrayUtils.mm
index a251ed7fc6..e8b3671977 100644
--- a/AsyncDisplayKit/Private/ASMultidimensionalArrayUtils.mm
+++ b/AsyncDisplayKit/Private/ASMultidimensionalArrayUtils.mm
@@ -43,7 +43,9 @@ static void ASRecursivelyUpdateMultidimensionalArrayAtIndexPaths(NSMutableArray
       curIdx++;
     }
 
-    updateBlock(mutableArray, indexSet, curIdx);
+    if (updateBlock){
+      updateBlock(mutableArray, indexSet, curIdx);
+    }
   }
 }
 
diff --git a/AsyncDisplayKit/TextKit/ASTextKitContext.mm b/AsyncDisplayKit/TextKit/ASTextKitContext.mm
index 7410ed9f45..e1f65a0122 100755
--- a/AsyncDisplayKit/TextKit/ASTextKitContext.mm
+++ b/AsyncDisplayKit/TextKit/ASTextKitContext.mm
@@ -75,7 +75,9 @@
                                                           NSTextContainer *))block
 {
   std::lock_guard<std::mutex> l(_textKitMutex);
-  block(_layoutManager, _textStorage, _textContainer);
+  if (block) {
+    block(_layoutManager, _textStorage, _textContainer);
+  }
 }
 
 @end
diff --git a/inferScript.sh b/inferScript.sh
new file mode 100755
index 0000000000..81919c1e81
--- /dev/null
+++ b/inferScript.sh
@@ -0,0 +1,8 @@
+#!/bin/sh
+
+if ! [ -x "$(command -v infer)" ]; then
+    echo "infer not found"
+    echo "Install infer with homebrew: brew install infer"
+else
+    infer --continue --reactive -- xcodebuild build -workspace AsyncDisplayKit.xcworkspace -scheme "AsyncDisplayKit-iOS" -configuration Debug -sdk iphonesimulator9.3
+fi