[map] Return rvalues from keys()/values()

src/hb-algs.hh

@@ -41,6 +41,13 @@ struct
 }
 HB_FUNCOBJ (hb_identity);
 
+struct
+{
+  template <typename T> hb_remove_reference<T>
+  operator () (T&& v) const { return v; }
+}
+HB_FUNCOBJ (hb_rvalue);
+
 struct
 {
   template <typename T> bool

src/hb-map.hh

@@ -221,12 +221,14 @@ struct hb_hashmap_t
     + hb_array (items, mask ? mask + 1 : 0)
     | hb_filter (&item_t::is_real)
     | hb_map (&item_t::key)
+    | hb_map (hb_rvalue)
   )
   auto values () const HB_AUTO_RETURN
   (
     + hb_array (items, mask ? mask + 1 : 0)
     | hb_filter (&item_t::is_real)
     | hb_map (&item_t::value)
+    | hb_map (hb_rvalue)
   )
 
   protected: