diff --git a/lib/Doctrine/ORM/UnitOfWork.php b/lib/Doctrine/ORM/UnitOfWork.php
index 803e6683c32..eb3111fb8d1 100644
--- a/lib/Doctrine/ORM/UnitOfWork.php
+++ b/lib/Doctrine/ORM/UnitOfWork.php
@@ -1735,7 +1735,7 @@ private function doMerge($entity, array &$visited, $prevManagedCopy = null, $ass
                             $managedCol->initialize();
 
                             // clear and set dirty a managed collection if its not also the same collection to merge from.
-                            if (!$managedCol->isEmpty() && $managedCol != $mergeCol) {
+                            if (!$managedCol->isEmpty() && $managedCol !== $mergeCol) {
                                 $managedCol->unwrap()->clear();
                                 $managedCol->setDirty(true);