diff --git a/peglib.h b/peglib.h
index 4ed126a..e2851f7 100644
--- a/peglib.h
+++ b/peglib.h
@@ -345,6 +345,8 @@ public:
     template <typename F, typename std::enable_if<std::is_same<F, std::nullptr_t>::value>::type*& = enabler>
     void operator=(F /*fn*/) {}
 
+    Action& operator=(const Action& rhs) = default;
+
     operator bool() const {
         return (bool)fn_;
     }