diff --git a/nano/node/transport/tcp_listener.hpp b/nano/node/transport/tcp_listener.hpp
index e8c86732fe..94fc9f12ae 100644
--- a/nano/node/transport/tcp_listener.hpp
+++ b/nano/node/transport/tcp_listener.hpp
@@ -86,7 +86,7 @@ class tcp_listener final
 	nano::container_info container_info () const;
 
 public: // Events
-	using connection_accepted_event_t = nano::observer_set<std::shared_ptr<nano::transport::tcp_socket> const &, std::shared_ptr<nano::transport::tcp_server>>;
+	using connection_accepted_event_t = nano::observer_set<std::shared_ptr<nano::transport::tcp_socket>, std::shared_ptr<nano::transport::tcp_server>>;
 	connection_accepted_event_t connection_accepted;
 
 private: // Dependencies