diff --git a/include/__functional_base_03 b/include/__functional_base_03
index e2f0e3e7..0a7ff62e 100644
--- a/include/__functional_base_03
+++ b/include/__functional_base_03
@@ -408,20 +408,15 @@ template <class _Rp, class _Tp, class _T1>
 inline _LIBCPP_INLINE_VISIBILITY
 typename enable_if
 <
+    is_member_object_pointer<_Rp _Tp::*>::value &&
     is_base_of<_Tp, typename remove_reference<_T1>::type>::value,
-    typename __apply_cv<_T1, _Rp>::type&
->::type
+   __apply_cv<_T1, _Rp>
+>::type::type&
 __invoke(_Rp _Tp::* __f, _T1& __t1)
 {
     return __t1.*__f;
 }
 
-template <class _Rp, class _Tp>
-inline _LIBCPP_INLINE_VISIBILITY
-void
-__invoke(_Rp _Tp::*)
-{
-}
 
 // forth bullet
 
@@ -439,10 +434,9 @@ struct __4th_helper<_T1, _Rp, true>
 template <class _Rp, class _Tp, class _T1>
 inline _LIBCPP_INLINE_VISIBILITY
 typename __4th_helper<_T1, _Rp,
-                      !is_base_of<_Tp,
-                                  typename remove_reference<_T1>::type
-                                 >::value
-                     >::type&
+    is_member_object_pointer<_Rp _Tp::*>::value &&
+    !is_base_of<_Tp, typename remove_reference<_T1>::type>::value
+>::type&
 __invoke(_Rp _Tp::* __f, _T1& __t1)
 {
     return (*__t1).*__f;
@@ -494,20 +488,20 @@ struct __invoke_return<_Fp, false>
     typedef decltype(__invoke(_VSTD::declval<_Fp&>())) type;
 };
 
-template <class _Tp, class _A0>
+template <class _Tp, class _A0, bool = is_member_object_pointer<_Tp>::value>
 struct __invoke_return0
 {
     typedef decltype(__invoke(_VSTD::declval<_Tp&>(), _VSTD::declval<_A0&>())) type;
 };
 
 template <class _Rp, class _Tp, class _A0>
-struct __invoke_return0<_Rp _Tp::*, _A0>
+struct __invoke_return0<_Rp _Tp::*, _A0, true>
 {
     typedef typename __apply_cv<_A0, _Rp>::type& type;
 };
 
 template <class _Rp, class _Tp, class _A0>
-struct __invoke_return0<_Rp _Tp::*, _A0*>
+struct __invoke_return0<_Rp _Tp::*, _A0*, true>
 {
     typedef typename __apply_cv<_A0, _Rp>::type& type;
 };
diff --git a/include/functional b/include/functional
index 939486ff..6c57de03 100644
--- a/include/functional
+++ b/include/functional
@@ -1260,10 +1260,6 @@ public:
         return __invoke(__f_, _VSTD::forward<_ArgTypes>(__args)...);
     }
 #else
-    typename __invoke_return<type>::type
-    operator() () const {
-        return __invoke(__f_);
-    }
 
     template <class _A0>
     typename __invoke_return0<type, _A0>::type