diff --git a/src/txmempool.h b/src/txmempool.h
index 687c474f8e0..2c77aef0de9 100644
--- a/src/txmempool.h
+++ b/src/txmempool.h
@@ -940,7 +940,7 @@ public:
      * m_temp_added and cannot be flushed to the back end. Only used for package validation. */
     void PackageAddTransaction(const CTransactionRef& tx);
     /** Get all coins in m_non_base_coins. */
-    std::unordered_set<COutPoint, SaltedOutpointHasher> GetNonBaseCoins() const { return m_non_base_coins; }
+    const std::unordered_set<COutPoint, SaltedOutpointHasher>& GetNonBaseCoins() const { return m_non_base_coins; }
     /** Clear m_temp_added and m_non_base_coins. */
     void Reset();
 };