diff --git a/jode/jode/expr/CheckNullOperator.java b/jode/jode/expr/CheckNullOperator.java
index 758ec5a..3024579 100644
--- a/jode/jode/expr/CheckNullOperator.java
+++ b/jode/jode/expr/CheckNullOperator.java
@@ -21,6 +21,7 @@ package jode.expr;
 import jode.type.Type;
 import jode.decompiler.LocalInfo;
 import jode.decompiler.TabbedPrintWriter;
+import jode.flow.VariableSet;
 
 /**
  * This is a pseudo operator, which represents the check against null
@@ -68,6 +69,12 @@ public class CheckNullOperator extends Operator {
 	local.remove();
     }
 
+    public void fillInGenSet(VariableSet in, VariableSet gen) {
+	if (gen != null)
+	    gen.addElement(local);
+	super.fillInGenSet(in, gen);
+    }
+
     public void dumpExpression(TabbedPrintWriter writer)
 	throws java.io.IOException {
 	writer.print("("+local.getName()+" = ");