1 files changed, 19 insertions, 0 deletions
diff --git a/container-search/src/main/java/com/yahoo/search/querytransform/LowercasingSearcher.java b/container-search/src/main/java/com/yahoo/search/querytransform/LowercasingSearcher.java
index d023c1f9143..1889c755833 100644
--- a/container-search/src/main/java/com/yahoo/search/querytransform/LowercasingSearcher.java
+++ b/container-search/src/main/java/com/yahoo/search/querytransform/LowercasingSearcher.java
@@ -64,6 +64,8 @@ public abstract class LowercasingSearcher extends Searcher {
                 }
             } else if (next instanceof WordAlternativesItem) {
                 lowerCase((WordAlternativesItem) next, indexFacts);
+            } else if (next instanceof StringInItem) {
+                lowerCase((StringInItem) next, indexFacts);
             }
         }
     }
@@ -144,6 +146,23 @@ public abstract class LowercasingSearcher extends Searcher {
 
     }
 
+    private void lowerCase(StringInItem set, IndexFacts.Session indexFacts) {
+        if ( ! syntheticLowerCaseCheck(set.getIndexName(), indexFacts, true)) {
+            return;
+        }
+
+        // set.getTokens() uses Set.copyOf(), thus modification to original set is not reflected in
+        // set being iterated over.
+        var originalTokens = set.getTokens();
+        for (String originalToken : originalTokens) {
+            String token = toLowerCase(originalToken);
+            if (!originalToken.equals(token)) {
+                set.removeToken(originalToken);
+                set.addToken(token);
+            }
+        }
+    }
+
     /**
      * Override this to control whether a given term should be lowercased.
      *