diff --git a/src/hb-iter.hh b/src/hb-iter.hh
index c74ea951e402eee4549d50b3b155ae07967573b0..7068aa4cc3da6d2f98fa072660899a9a72ccc790 100644
--- a/src/hb-iter.hh
+++ b/src/hb-iter.hh
@@ -281,10 +281,13 @@ struct hb_map_iter_factory_t
   private:
   Proj f;
 };
-template <typename Proj>
-inline hb_map_iter_factory_t<Proj>
-hb_map (Proj&& f)
-{ return hb_map_iter_factory_t<Proj> (f); }
+static const struct
+{
+  template <typename Proj>
+  hb_map_iter_factory_t<Proj>
+  operator () (Proj&& f) const
+  { return hb_map_iter_factory_t<Proj> (f); }
+} hb_map HB_UNUSED;
 
 template <typename Iter, typename Pred, typename Proj,
 	 hb_enable_if (hb_is_iterator (Iter))>