diff --git a/lib/Doctrine/ORM/Mapping/ClassMetadataFactory.php b/lib/Doctrine/ORM/Mapping/ClassMetadataFactory.php
index a74ddac8b..2aaa30a44 100644
--- a/lib/Doctrine/ORM/Mapping/ClassMetadataFactory.php
+++ b/lib/Doctrine/ORM/Mapping/ClassMetadataFactory.php
@@ -406,7 +406,7 @@ class ClassMetadataFactory implements ClassMetadataFactoryInterface
      */
     private function addInheritedFields(ClassMetadata $subClass, ClassMetadata $parentClass)
     {
-        foreach ($parentClass->fieldMappings as $fieldName => $mapping) {
+        foreach ($parentClass->fieldMappings as $mapping) {
             if ( ! isset($mapping['inherited']) && ! $parentClass->isMappedSuperclass) {
                 $mapping['inherited'] = $parentClass->name;
             }