[iter] Add hb_iter_with_fallback_t instead
diff --git a/src/test-iter.cc b/src/test-iter.cc
index 83f0bef..cd94be8 100644
--- a/src/test-iter.cc
+++ b/src/test-iter.cc
@@ -33,10 +33,7 @@
 
 
 template <typename T>
-struct array_iter_t :
-  hb_iter_with_mixin_t<hb_iter_fallback_mixin_t,
-		       array_iter_t<T>,
-		       T&>
+struct array_iter_t : hb_iter_with_fallback_t<array_iter_t<T>, T&>
 {
   array_iter_t (hb_array_t<T> arr_) : arr (arr_) {}