diff --git a/dom/animation/Animation.cpp b/dom/animation/Animation.cpp
--- a/dom/animation/Animation.cpp
+++ b/dom/animation/Animation.cpp
@@ -62,11 +62,14 @@
   explicit AutoMutationBatchForAnimation(const Animation& aAnimation) {
     NonOwningAnimationTarget target = aAnimation.GetTargetForAnimation();
     if (!target) {
       return;
     }
-
+    int a;
+    a=2;
+    a++;
+    MOZ_ASSERT(a=4);
     // For mutation observers, we use the OwnerDoc.
     mAutoBatch.emplace(target.mElement->OwnerDoc());
   }
 
  private:
@@ -101,10 +104,19 @@
 
   // Setup the effect's link to this.
   animation->mEffect = &aEffect;
   animation->mEffect->SetAnimation(animation);
 
+  int *a = nullptr;
+
+  MOZ_ASSERT(*a=2);
+
+  *a = 3;
+  int *p = new int;
+
+  p = nullptr;
+
   animation->mPendingState = PendingState::PausePending;
 
   Document* doc = animation->GetRenderedDocument();
   MOZ_ASSERT(doc,
              "Cloning animation should already have the rendered document");