diff --git a/include/upa/url.h b/include/upa/url.h
index ebdbbc7..ec8ff3c 100644
--- a/include/upa/url.h
+++ b/include/upa/url.h
@@ -668,9 +668,9 @@ class url {
 
     friend bool operator==(const url& lhs, const url& rhs) noexcept;
     friend struct std::hash<url>;
-    friend detail::url_serializer;
-    friend detail::url_setter;
-    friend detail::url_parser;
+    friend class detail::url_serializer;
+    friend class detail::url_setter;
+    friend class detail::url_parser;
     friend class url_search_params;
 };
 
diff --git a/include/upa/url_search_params.h b/include/upa/url_search_params.h
index 98c4cba..383d354 100644
--- a/include/upa/url_search_params.h
+++ b/include/upa/url_search_params.h
@@ -372,7 +372,7 @@ class url_search_params
     void update();
 
     friend class url;
-    friend detail::url_search_params_ptr;
+    friend class detail::url_search_params_ptr;
 
 private:
     name_value_list params_;