--- a/storage/mozStorageConnection.cpp
+++ b/storage/mozStorageConnection.cpp
@@ -410,17 +410,17 @@ public:
       nsCOMPtr<nsIThread> thread;
       (void)NS_GetMainThread(getter_AddRefs(thread));
       (void)thread->Dispatch(mCallbackEvent, NS_DISPATCH_NORMAL);
     }
 
     return NS_OK;
   }
 
-  ~AsyncCloseConnection() {
+  ~AsyncCloseConnection() override {
     NS_ReleaseOnMainThread(mConnection.forget());
     NS_ReleaseOnMainThread(mCallbackEvent.forget());
   }
 private:
   RefPtr<Connection> mConnection;
   sqlite3 *mNativeConnection;
   nsCOMPtr<nsIRunnable> mCallbackEvent;
   nsCOMPtr<nsIThread> mAsyncExecutionThread;
@@ -468,17 +468,17 @@ public:
 private:
   nsresult Dispatch(nsresult aResult, nsISupports* aValue) {
     RefPtr<CallbackComplete> event = new CallbackComplete(aResult,
                                                             aValue,
                                                             mCallback.forget());
     return mClone->threadOpenedOn->Dispatch(event, NS_DISPATCH_NORMAL);
   }
 
-  ~AsyncInitializeClone() {
+  ~AsyncInitializeClone() override {
     nsCOMPtr<nsIThread> thread;
     DebugOnly<nsresult> rv = NS_GetMainThread(getter_AddRefs(thread));
     MOZ_ASSERT(NS_SUCCEEDED(rv));
 
     // Handle ambiguous nsISupports inheritance.
     NS_ProxyRelease(thread, mConnection.forget());
     NS_ProxyRelease(thread, mClone.forget());
 

--- a/storage/test/test_AsXXX_helpers.cpp
+++ b/storage/test/test_AsXXX_helpers.cpp
@@ -16,17 +16,17 @@
 
 class Spinner : public AsyncStatementSpinner
 {
 public:
   NS_DECL_ISUPPORTS_INHERITED
   NS_DECL_ASYNCSTATEMENTSPINNER
   Spinner() {}
 protected:
-  virtual ~Spinner() = default;
+  ~Spinner() override = default;
 };
 
 NS_IMPL_ISUPPORTS_INHERITED0(Spinner,
                              AsyncStatementSpinner)
 
 NS_IMETHODIMP
 Spinner::HandleResult(mozIStorageResultSet *aResultSet)
 {