diff --git a/src/corelib/tools/qduplicatetracker_p.h b/src/corelib/tools/qduplicatetracker_p.h
index 99068c01a3..cd57d4aed5 100644
--- a/src/corelib/tools/qduplicatetracker_p.h
+++ b/src/corelib/tools/qduplicatetracker_p.h
@@ -84,6 +84,18 @@ public:
         set.insert(s);
         const int n = set.size();
         inserted = qExchange(setSize, n) != n;
+#endif
+        return !inserted;
+    }
+    Q_REQUIRED_RESULT bool hasSeen(T &&s)
+    {
+        bool inserted;
+#ifdef __cpp_lib_memory_resource
+        inserted = set.insert(std::move(s)).second;
+#else
+        set.insert(std::move(s));
+        const int n = set.size();
+        inserted = qExchange(setSize, n) != n;
 #endif
         return !inserted;
     }