More perfect forward

Author: cyyever

include/pybind11/detail/init.h

@@ -257,15 +257,15 @@ struct alias_constructor {
         typename... Extra,
         enable_if_t<Class::has_alias && std::is_constructible<Alias<Class>, Args...>::value, int>
         = 0>
-    static void execute(Class &cl, const Extra &...extra) {
+    static void execute(Class &cl, Extra &&...extra) {
         cl.def(
             "__init__",
             [](value_and_holder &v_h, Args... args) {
                 v_h.value_ptr()
                     = construct_or_initialize<Alias<Class>>(std::forward<Args>(args)...);
             },
             is_new_style_constructor(),
-            extra...);
+            std::forward<Extra>(extra)...);
     }
 };
 

include/pybind11/pybind11.h

@@ -110,6 +110,7 @@ class cpp_function : public function {
     // NOLINTNEXTLINE(google-explicit-constructor)
     cpp_function(std::nullptr_t) {}
     cpp_function(std::nullptr_t, const is_setter &) {}
+    cpp_function(std::nullptr_t, is_setter &&) {}
 
     /// Construct a cpp_function from a vanilla function pointer
     template <typename Return, typename... Args, typename... Extra>
@@ -123,9 +124,9 @@ class cpp_function : public function {
               typename... Extra,
               typename = detail::enable_if_t<detail::is_lambda<Func>::value>>
     // NOLINTNEXTLINE(google-explicit-constructor)
-    cpp_function(Func &&f, const Extra &...extra) {
+    cpp_function(Func &&f, Extra &&...extra) {
         initialize(
-            std::forward<Func>(f), (detail::function_signature_t<Func> *) nullptr, extra...);
+            std::forward<Func>(f), (detail::function_signature_t<Func> *) nullptr, std::forward<Extra>(extra)...);
     }
 
     /// Construct a cpp_function from a class method (non-const, no ref-qualifier)