1 files changed, 12 insertions, 1 deletions
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/NegFunction.java b/container-search/src/main/java/com/yahoo/search/grouping/request/NegFunction.java
index 7e05b02b59e..ad3b892970c 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/NegFunction.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/NegFunction.java
@@ -8,6 +8,7 @@ import java.util.Arrays;
  * negative of the results of the argument.
  *
  * @author Simon Thoresen Hult
+ * @author bratseth
  */
 public class NegFunction extends FunctionNode {
 
@@ -17,7 +18,17 @@ public class NegFunction extends FunctionNode {
      * @param exp The expression to evaluate, must evaluate to a number.
      */
     public NegFunction(GroupingExpression exp) {
-        super("neg", Arrays.asList(exp));
+        this(null, null, exp);
     }
+
+    private NegFunction(String label, Integer level, GroupingExpression exp) {
+        super("neg", label, level, Arrays.asList(exp));
+    }
+
+    @Override
+    public NegFunction copy() {
+        return new NegFunction(getLabel(), getLevelOrNull(), getArg(0).copy());
+    }
+
 }