diff --git a/lib/Doctrine/ORM/Query/AST/WhenClause.php b/lib/Doctrine/ORM/Query/AST/WhenClause.php
index 7d9fbf49399..504a5e276ad 100644
--- a/lib/Doctrine/ORM/Query/AST/WhenClause.php
+++ b/lib/Doctrine/ORM/Query/AST/WhenClause.php
@@ -12,7 +12,7 @@
 class WhenClause extends Node
 {
     /** @var ConditionalExpression */
-    public $caseConditionExpression = null;
+    public $caseConditionExpression;
 
     /** @var mixed */
     public $thenScalarExpression = null;