diff --git a/src/hb-iter.hh b/src/hb-iter.hh
index 2448e1944..140e55365 100644
--- a/src/hb-iter.hh
+++ b/src/hb-iter.hh
@@ -119,9 +119,11 @@ struct hb_iter_t
   iter_t  operator << (const T v) && { **thiz() = v; ++*thiz(); return *thiz(); }
 
   protected:
-  hb_iter_t () {}
-  hb_iter_t (const hb_iter_t &o HB_UNUSED) {}
-  void operator = (const hb_iter_t &o HB_UNUSED) {}
+  hb_iter_t () = default;
+  hb_iter_t (const hb_iter_t &o HB_UNUSED) = default;
+  hb_iter_t (hb_iter_t &&o HB_UNUSED) = default;
+  hb_iter_t& operator = (const hb_iter_t &o HB_UNUSED) = default;
+  hb_iter_t& operator = (hb_iter_t &&o HB_UNUSED) = default;
 };
 
 #define HB_ITER_USING(Name) \
@@ -214,9 +216,11 @@ struct hb_iter_fallback_mixin_t
   }
 
   protected:
-  hb_iter_fallback_mixin_t () {}
-  hb_iter_fallback_mixin_t (const hb_iter_fallback_mixin_t &o HB_UNUSED) {}
-  void operator = (const hb_iter_fallback_mixin_t &o HB_UNUSED) {}
+  hb_iter_fallback_mixin_t () = default;
+  hb_iter_fallback_mixin_t (const hb_iter_fallback_mixin_t &o HB_UNUSED) = default;
+  hb_iter_fallback_mixin_t (hb_iter_fallback_mixin_t &&o HB_UNUSED) = default;
+  hb_iter_fallback_mixin_t& operator = (const hb_iter_fallback_mixin_t &o HB_UNUSED) = default;
+  hb_iter_fallback_mixin_t& operator = (hb_iter_fallback_mixin_t &&o HB_UNUSED) = default;
 };
 
 template <typename iter_t, typename item_t = typename iter_t::__item_t__>
@@ -225,11 +229,11 @@ struct hb_iter_with_fallback_t :
   hb_iter_fallback_mixin_t<iter_t, item_t>
 {
   protected:
-  hb_iter_with_fallback_t () {}
-  hb_iter_with_fallback_t (const hb_iter_with_fallback_t &o HB_UNUSED) :
-    hb_iter_t<iter_t, item_t> (o),
-    hb_iter_fallback_mixin_t<iter_t, item_t> (o) {}
-  void operator = (const hb_iter_with_fallback_t &o HB_UNUSED) {}
+  hb_iter_with_fallback_t () = default;
+  hb_iter_with_fallback_t (const hb_iter_with_fallback_t &o HB_UNUSED) = default;
+  hb_iter_with_fallback_t (hb_iter_with_fallback_t &&o HB_UNUSED) = default;
+  hb_iter_with_fallback_t& operator = (const hb_iter_with_fallback_t &o HB_UNUSED) = default;
+  hb_iter_with_fallback_t& operator = (hb_iter_with_fallback_t &&o HB_UNUSED) = default;
 };
 
 /*