address compilation issue in MSVC

include/pybind11/cast.h

@@ -507,8 +507,9 @@ protected:
     template <typename T> /* Used to select the right casting operator in the two functions below */
     template <typename T> /* Used to select the right casting operator in the two functions below */
     using cast_target =
     using cast_target =
         typename std::conditional<
         typename std::conditional<
-            is_tuple<typename intrinsic_type<T>::type>::value, /* special case: tuple/pair -> pass by value */
-            typename intrinsic_type<T>::type,
+            is_specialization_of<typename intrinsic_type<T>::type, std::tuple>::value ||
+            is_specialization_of<typename intrinsic_type<T>::type, std::pair>::value,
+            typename intrinsic_type<T>::type, /* special case: tuple/pair -> pass by value */
             typename std::conditional<
             typename std::conditional<
                 std::is_pointer<T>::value,
                 std::is_pointer<T>::value,
                 typename std::add_pointer<typename intrinsic_type<T>::type>::type, /* pass using pointer */
                 typename std::add_pointer<typename intrinsic_type<T>::type>::type, /* pass using pointer */

include/pybind11/common.h

@@ -257,10 +257,10 @@ template <typename T>  struct is_copy_constructible {
     static const bool value = std::is_same<std::true_type, decltype(test<T>(nullptr))>::value;
     static const bool value = std::is_same<std::true_type, decltype(test<T>(nullptr))>::value;
 };
 };
 
 
-/// Helper type determine if another type is a variant of a pair/tuple
-template <typename T> struct is_tuple : std::false_type { };
-template <typename... Args> struct is_tuple <std::tuple<Args...>> : std::true_type { };
-template <typename... Args> struct is_tuple <std::pair<Args...>> : std::true_type { };
+template <typename T, template <typename...> class Template>
+struct is_specialization_of : std::false_type {};
+template <template <typename...> class Template, typename... Args>
+struct is_specialization_of<Template<Args...>, Template> : std::true_type {};
 
 
 /// Helper type to replace 'void' in some expressions
 /// Helper type to replace 'void' in some expressions
 struct void_type { };
 struct void_type { };