diff --git a/src/hb-iter.hh b/src/hb-iter.hh
index c820c8fb4..8d2ff80c2 100644
--- a/src/hb-iter.hh
+++ b/src/hb-iter.hh
@@ -480,7 +480,7 @@ struct hb_reduce_t
 
   template <typename Iter,
 	    hb_requires (hb_is_iterator (Iter)),
-	    typename AccuT = hb_remove_reference<decltype (hb_declval (Redu) (hb_declval (InitT), hb_declval (typename Iter::item_t)))>>
+	    typename AccuT = hb_decay<decltype (hb_declval (Redu) (hb_declval (InitT), hb_declval (typename Iter::item_t)))>>
   AccuT
   operator () (Iter it)
   {