diff --git a/dom/ipc/TabParent.cpp b/dom/ipc/TabParent.cpp
index f1efd2689e38..95406f98368e 100644
--- a/dom/ipc/TabParent.cpp
+++ b/dom/ipc/TabParent.cpp
@@ -973,6 +973,11 @@ TabParent::RecvPDocAccessibleConstructor(PDocAccessibleParent* aDoc,
 #ifdef XP_WIN
     a11y::WrapperFor(doc)->SetID(aMsaaID);
     MOZ_ASSERT(!aDocCOMProxy.IsNull());
+#ifdef NIGHTLY_BUILD
+    if (aDocCOMProxy.IsNull()) {
+      return IPC_FAIL(this, "Constructing a top-level PDocAccessible with null COM proxy");
+    }
+#endif
 
     RefPtr<IAccessible> proxy(aDocCOMProxy.Get());
     doc->SetCOMInterface(proxy);
diff --git a/ipc/mscom/Interceptor.cpp b/ipc/mscom/Interceptor.cpp
index 52e192705db7..a62a51086ecd 100644
--- a/ipc/mscom/Interceptor.cpp
+++ b/ipc/mscom/Interceptor.cpp
@@ -28,12 +28,26 @@
 #include "nsThreadUtils.h"
 #include "nsXULAppAPI.h"
 
+#if defined(MOZ_DEV_EDITION) || defined(RELEASE_OR_BETA)
+
 #define ENSURE_HR_SUCCEEDED(hr) \
-  MOZ_ASSERT(SUCCEEDED((HRESULT)hr)); \
   if (FAILED((HRESULT)hr)) { \
     return hr; \
   }
 
+#else
+
+#define ENSURE_HR_SUCCEEDED(hr) \
+  if (FAILED((HRESULT)hr)) { \
+    nsPrintfCString location("ENSURE_HR_SUCCEEDED \"%s\": %u", __FILE__, __LINE__); \
+    nsPrintfCString hrAsStr("0x%08X", (HRESULT)hr); \
+    CrashReporter::AnnotateCrashReport(location, hrAsStr); \
+    MOZ_DIAGNOSTIC_ASSERT(SUCCEEDED((HRESULT)hr)); \
+    return hr; \
+  }
+
+#endif // defined(MOZ_DEV_EDITION) || defined(RELEASE_OR_BETA)
+
 namespace mozilla {
 namespace mscom {
 namespace detail {