diff --git a/jode/jode/expr/NopOperator.java b/jode/jode/expr/NopOperator.java
index 7ac6888..035c9c4 100644
--- a/jode/jode/expr/NopOperator.java
+++ b/jode/jode/expr/NopOperator.java
@@ -41,10 +41,18 @@ public class NopOperator extends SimpleOperator {
         return 0;
     }
 
+    public Expression addOperand(Expression op) {
+	return op;
+    }
+
     public int getOperandPriority(int i) {
         return 0;
     }
 
+    public boolean isConstant() {
+	return false;
+    }
+
     public boolean equals(Object o) {
 	return (o instanceof NopOperator);
     }