Making rvp::move default for py::cast with rvalue reference

Author: YannickJadoul

include/pybind11/cast.h

@@ -1670,9 +1670,11 @@ template <typename T, detail::enable_if_t<!detail::is_pyobject<T>::value, int> =
 object cast(T &&value, return_value_policy policy = return_value_policy::automatic_reference,
             handle parent = handle()) {
     if (policy == return_value_policy::automatic)
-        policy = std::is_pointer<T>::value ? return_value_policy::take_ownership : return_value_policy::copy;
+        policy = std::is_pointer<T>::value ? return_value_policy::take_ownership :
+                 std::is_lvalue_reference<T>::value ? return_value_policy::copy : return_value_policy::move;
     else if (policy == return_value_policy::automatic_reference)
-        policy = std::is_pointer<T>::value ? return_value_policy::reference : return_value_policy::copy;
+        policy = std::is_pointer<T>::value ? return_value_policy::reference :
+                 std::is_lvalue_reference<T>::value ? return_value_policy::copy : return_value_policy::move;
     return reinterpret_steal<object>(detail::make_caster<T>::cast(std::forward<T>(value), policy, parent));
 }