minor adjustment to detail::is_copy_constructible (fixes #70)
diff --git a/include/pybind11/common.h b/include/pybind11/common.h
index a63b7f5..2a00fa7 100644
--- a/include/pybind11/common.h
+++ b/include/pybind11/common.h
@@ -247,7 +247,7 @@
/** \brief SFINAE helper class to check if a copy constructor is usable (in contrast to
* std::is_copy_constructible, this class also checks if the 'new' operator is accessible */
template <typename T> struct is_copy_constructible {
- template <typename T2> static std::true_type test(decltype(new T2(std::declval<T2>())) *);
+ template <typename T2> static std::true_type test(decltype(new T2(std::declval<std::add_lvalue_reference<T2>::type>())) *);
template <typename T2> static std::false_type test(...);
static const bool value = std::is_same<std::true_type, decltype(test<T>(nullptr))>::value;
};