Check for b being null

1 files changed, 3 insertions, 0 deletions

diff --git a/container-search/src/main/java/com/yahoo/search/query/QueryTree.java b/container-search/src/main/java/com/yahoo/search/query/QueryTree.java
index 1bf176e2131..1c7e69583e6 100644
--- a/container-search/src/main/java/com/yahoo/search/query/QueryTree.java
+++ b/container-search/src/main/java/com/yahoo/search/query/QueryTree.java
@@ -123,6 +123,9 @@ public class QueryTree extends CompositeItem {
         if (a == null || a instanceof NullItem) {
             return b;
         }
+        else if (b == null || b instanceof NullItem) {
+            return a;
+        }
         else if (a instanceof NotItem && b instanceof NotItem) {
             NotItem notItemA = (NotItem)a;
             NotItem notItemB = (NotItem)b;