diff --git a/dom/indexedDB/ActorsParent.cpp b/dom/indexedDB/ActorsParent.cpp
index 84be5f30af1c..e58a3461ab30 100644
--- a/dom/indexedDB/ActorsParent.cpp
+++ b/dom/indexedDB/ActorsParent.cpp
@@ -4915,7 +4915,7 @@ class DatabaseConnection::UpdateRefcountFunction::DatabaseUpdateFunction final {
   CachedStatement mSelectStatement;
   CachedStatement mInsertStatement;
 
-  UpdateRefcountFunction* mFunction;
+  UpdateRefcountFunction* const mFunction;
 
   nsresult mErrorCode;