diff --git a/include/__functional_base b/include/__functional_base
index 3ff2e35..ef9cc03 100644
--- a/include/__functional_base
+++ b/include/__functional_base
@@ -515,44 +515,116 @@
 #ifndef _LIBCPP_HAS_NO_VARIADICS
     // invoke
     template <class... _ArgTypes>
-       _LIBCPP_INLINE_VISIBILITY
-       typename __invoke_of<type&, _ArgTypes...>::type
-          operator() (_ArgTypes&&... __args) const
-          {
-              return __invoke(get(), _VSTD::forward<_ArgTypes>(__args)...);
-          }
+    _LIBCPP_INLINE_VISIBILITY
+    typename __invoke_of<type&, _ArgTypes...>::type
+    operator() (_ArgTypes&&... __args) const {
+        return __invoke(get(), _VSTD::forward<_ArgTypes>(__args)...);
+    }
 #else
 
     _LIBCPP_INLINE_VISIBILITY
     typename __invoke_return<type>::type
-       operator() () const
-       {
-           return __invoke(get());
-       }
+    operator() () const {
+        return __invoke(get());
+    }
 
     template <class _A0>
-       _LIBCPP_INLINE_VISIBILITY
-       typename __invoke_return0<type&, _A0>::type
-          operator() (_A0& __a0) const
-          {
-              return __invoke<type&, _A0>(get(), __a0);
-          }
+    _LIBCPP_INLINE_VISIBILITY
+    typename __invoke_return0<type, _A0>::type
+    operator() (_A0& __a0) const {
+        return __invoke(get(), __a0);
+    }
+
+    template <class _A0>
+    _LIBCPP_INLINE_VISIBILITY
+    typename __invoke_return0<type, _A0 const>::type
+    operator() (_A0 const& __a0) const {
+        return __invoke(get(), __a0);
+    }
 
     template <class _A0, class _A1>
-       _LIBCPP_INLINE_VISIBILITY
-       typename __invoke_return1<type&, _A0, _A1>::type
-          operator() (_A0& __a0, _A1& __a1) const
-          {
-              return __invoke<type&, _A0, _A1>(get(), __a0, __a1);
-          }
+    _LIBCPP_INLINE_VISIBILITY
+    typename __invoke_return1<type, _A0, _A1>::type
+    operator() (_A0& __a0, _A1& __a1) const {
+        return __invoke(get(), __a0, __a1);
+    }
+
+    template <class _A0, class _A1>
+    _LIBCPP_INLINE_VISIBILITY
+    typename __invoke_return1<type, _A0 const, _A1>::type
+    operator() (_A0 const& __a0, _A1& __a1) const {
+        return __invoke(get(), __a0, __a1);
+    }
+
+    template <class _A0, class _A1>
+    _LIBCPP_INLINE_VISIBILITY
+    typename __invoke_return1<type, _A0, _A1 const>::type
+    operator() (_A0& __a0, _A1 const& __a1) const {
+        return __invoke(get(), __a0, __a1);
+    }
+
+    template <class _A0, class _A1>
+    _LIBCPP_INLINE_VISIBILITY
+    typename __invoke_return1<type, _A0 const, _A1 const>::type
+    operator() (_A0 const& __a0, _A1 const& __a1) const {
+        return __invoke(get(), __a0, __a1);
+    }
 
     template <class _A0, class _A1, class _A2>
-       _LIBCPP_INLINE_VISIBILITY
-       typename __invoke_return2<type&, _A0, _A1, _A2>::type
-          operator() (_A0& __a0, _A1& __a1, _A2& __a2) const
-          {
-              return __invoke<type&, _A0, _A1, _A2>(get(), __a0, __a1, __a2);
-          }
+    _LIBCPP_INLINE_VISIBILITY
+    typename __invoke_return2<type, _A0, _A1, _A2>::type
+    operator() (_A0& __a0, _A1& __a1, _A2& __a2) const {
+        return __invoke(get(), __a0, __a1, __a2);
+    }
+
+    template <class _A0, class _A1, class _A2>
+    _LIBCPP_INLINE_VISIBILITY
+    typename __invoke_return2<type, _A0 const, _A1, _A2>::type
+    operator() (_A0 const& __a0, _A1& __a1, _A2& __a2) const {
+        return __invoke(get(), __a0, __a1, __a2);
+    }
+
+    template <class _A0, class _A1, class _A2>
+    _LIBCPP_INLINE_VISIBILITY
+    typename __invoke_return2<type, _A0, _A1 const, _A2>::type
+    operator() (_A0& __a0, _A1 const& __a1, _A2& __a2) const {
+        return __invoke(get(), __a0, __a1, __a2);
+    }
+
+    template <class _A0, class _A1, class _A2>
+    _LIBCPP_INLINE_VISIBILITY
+    typename __invoke_return2<type, _A0, _A1, _A2 const>::type
+    operator() (_A0& __a0, _A1& __a1, _A2 const& __a2) const {
+        return __invoke(get(), __a0, __a1, __a2);
+    }
+
+    template <class _A0, class _A1, class _A2>
+    _LIBCPP_INLINE_VISIBILITY
+    typename __invoke_return2<type, _A0 const, _A1 const, _A2>::type
+    operator() (_A0 const& __a0, _A1 const& __a1, _A2& __a2) const {
+        return __invoke(get(), __a0, __a1, __a2);
+    }
+
+    template <class _A0, class _A1, class _A2>
+    _LIBCPP_INLINE_VISIBILITY
+    typename __invoke_return2<type, _A0 const, _A1, _A2 const>::type
+    operator() (_A0 const& __a0, _A1& __a1, _A2 const& __a2) const {
+        return __invoke(get(), __a0, __a1, __a2);
+    }
+
+    template <class _A0, class _A1, class _A2>
+    _LIBCPP_INLINE_VISIBILITY
+    typename __invoke_return2<type, _A0, _A1 const, _A2 const>::type
+    operator() (_A0& __a0, _A1 const& __a1, _A2 const& __a2) const {
+        return __invoke(get(), __a0, __a1, __a2);
+    }
+
+    template <class _A0, class _A1, class _A2>
+    _LIBCPP_INLINE_VISIBILITY
+    typename __invoke_return2<type, _A0 const, _A1 const, _A2 const>::type
+    operator() (_A0 const& __a0, _A1 const& __a1, _A2 const& __a2) const {
+        return __invoke(get(), __a0, __a1, __a2);
+    }
 #endif // _LIBCPP_HAS_NO_VARIADICS
 };
 
diff --git a/include/__functional_base_03 b/include/__functional_base_03
index 0a7ff62..8407dcf 100644
--- a/include/__functional_base_03
+++ b/include/__functional_base_03
@@ -14,431 +14,128 @@
 // manual variadic expansion for <functional>
 
 // __invoke
+
+template <class _Ret, class _T1, bool _IsFunc, bool _IsBase>
+struct __enable_invoke_imp;
+
+template <class _Ret, class _T1>
+struct __enable_invoke_imp<_Ret, _T1, true, true> {
+    typedef _Ret _Bullet1;
+    typedef _Bullet1 type;
+};
+
+template <class _Ret, class _T1>
+struct __enable_invoke_imp<_Ret, _T1, true, false>  {
+    typedef _Ret _Bullet2;
+    typedef _Bullet2 type;
+};
+
+template <class _Ret, class _T1>
+struct __enable_invoke_imp<_Ret, _T1, false, true>  {
+    typedef typename add_lvalue_reference<
+                typename __apply_cv<_T1, _Ret>::type
+            >::type _Bullet3;
+    typedef _Bullet3 type;
+};
+
+template <class _Ret, class _T1>
+struct __enable_invoke_imp<_Ret, _T1, false, false>  {
+    typedef typename add_lvalue_reference<
+                typename __apply_cv<decltype(*_VSTD::declval<_T1>()), _Ret>::type
+            >::type _Bullet4;
+    typedef _Bullet4 type;
+};
+
+template <class _Ret, class _T1>
+struct __enable_invoke_imp<_Ret, _T1*, false, false>  {
+    typedef typename add_lvalue_reference<
+                typename __apply_cv<_T1, _Ret>::type
+            >::type _Bullet4;
+    typedef _Bullet4  type;
+};
+
+template <class _Fn, class _T1,
+          class _Traits = __member_pointer_traits<_Fn>,
+          class _Ret = typename _Traits::_ReturnType,
+          class _Class = typename _Traits::_ClassType>
+struct __enable_invoke : __enable_invoke_imp<
+    _Ret, _T1,
+    is_member_function_pointer<_Fn>::value,
+    is_base_of<_Class, typename remove_reference<_T1>::type>::value>
+{
+};
+
+__nat __invoke(__any, ...);
+
 // first bullet
 
-template <class _Rp, class _Tp, class _T1>
+template <class _Fn, class _T1>
 inline _LIBCPP_INLINE_VISIBILITY
-typename enable_if
-<
-    is_base_of<_Tp, typename remove_reference<_T1>::type>::value,
-    _Rp
->::type
-__invoke(_Rp (_Tp::*__f)(), _T1& __t1)
-{
+typename __enable_invoke<_Fn, _T1>::_Bullet1
+__invoke(_Fn __f, _T1& __t1) {
     return (__t1.*__f)();
 }
 
-template <class _Rp, class _Tp, class _T1, class _A0>
+template <class _Fn, class _T1, class _A0>
 inline _LIBCPP_INLINE_VISIBILITY
-typename enable_if
-<
-    is_base_of<_Tp, typename remove_reference<_T1>::type>::value,
-    _Rp
->::type
-__invoke(_Rp (_Tp::*__f)(_A0), _T1& __t1, _A0& __a0)
-{
+typename __enable_invoke<_Fn, _T1>::_Bullet1
+__invoke(_Fn __f, _T1& __t1, _A0& __a0) {
     return (__t1.*__f)(__a0);
 }
 
-template <class _Rp, class _Tp, class _T1, class _A0, class _A1>
+template <class _Fn, class _T1, class _A0, class _A1>
 inline _LIBCPP_INLINE_VISIBILITY
-typename enable_if
-<
-    is_base_of<_Tp, typename remove_reference<_T1>::type>::value,
-    _Rp
->::type
-__invoke(_Rp (_Tp::*__f)(_A0, _A1), _T1& __t1, _A0& __a0, _A1& __a1)
-{
+typename __enable_invoke<_Fn, _T1>::_Bullet1
+__invoke(_Fn __f, _T1& __t1, _A0& __a0, _A1& __a1) {
     return (__t1.*__f)(__a0, __a1);
 }
 
-template <class _Rp, class _Tp, class _T1, class _A0, class _A1, class _A2>
+template <class _Fn, class _T1, class _A0, class _A1, class _A2>
 inline _LIBCPP_INLINE_VISIBILITY
-typename enable_if
-<
-    is_base_of<_Tp, typename remove_reference<_T1>::type>::value,
-    _Rp
->::type
-__invoke(_Rp (_Tp::*__f)(_A0, _A1, _A2), _T1& __t1, _A0& __a0, _A1& __a1, _A2& __a2)
-{
+typename __enable_invoke<_Fn, _T1>::_Bullet1
+__invoke(_Fn __f, _T1& __t1, _A0& __a0, _A1& __a1, _A2& __a2) {
     return (__t1.*__f)(__a0, __a1, __a2);
 }
 
-template <class _Rp, class _Tp, class _T1>
+template <class _Fn, class _T1>
 inline _LIBCPP_INLINE_VISIBILITY
-typename enable_if
-<
-    is_base_of<_Tp, typename remove_reference<_T1>::type>::value,
-    _Rp
->::type
-__invoke(_Rp (_Tp::*__f)() const, _T1& __t1)
-{
-    return (__t1.*__f)();
-}
-
-template <class _Rp, class _Tp, class _T1, class _A0>
-inline _LIBCPP_INLINE_VISIBILITY
-typename enable_if
-<
-    is_base_of<_Tp, typename remove_reference<_T1>::type>::value,
-    _Rp
->::type
-__invoke(_Rp (_Tp::*__f)(_A0) const, _T1& __t1, _A0& __a0)
-{
-    return (__t1.*__f)(__a0);
-}
-
-template <class _Rp, class _Tp, class _T1, class _A0, class _A1>
-inline _LIBCPP_INLINE_VISIBILITY
-typename enable_if
-<
-    is_base_of<_Tp, typename remove_reference<_T1>::type>::value,
-    _Rp
->::type
-__invoke(_Rp (_Tp::*__f)(_A0, _A1) const, _T1& __t1, _A0& __a0, _A1& __a1)
-{
-    return (__t1.*__f)(__a0, __a1);
-}
-
-template <class _Rp, class _Tp, class _T1, class _A0, class _A1, class _A2>
-inline _LIBCPP_INLINE_VISIBILITY
-typename enable_if
-<
-    is_base_of<_Tp, typename remove_reference<_T1>::type>::value,
-    _Rp
->::type
-__invoke(_Rp (_Tp::*__f)(_A0, _A1, _A2) const, _T1& __t1, _A0& __a0, _A1& __a1, _A2& __a2)
-{
-    return (__t1.*__f)(__a0, __a1, __a2);
-}
-
-template <class _Rp, class _Tp, class _T1>
-inline _LIBCPP_INLINE_VISIBILITY
-typename enable_if
-<
-    is_base_of<_Tp, typename remove_reference<_T1>::type>::value,
-    _Rp
->::type
-__invoke(_Rp (_Tp::*__f)() volatile, _T1& __t1)
-{
-    return (__t1.*__f)();
-}
-
-template <class _Rp, class _Tp, class _T1, class _A0>
-inline _LIBCPP_INLINE_VISIBILITY
-typename enable_if
-<
-    is_base_of<_Tp, typename remove_reference<_T1>::type>::value,
-    _Rp
->::type
-__invoke(_Rp (_Tp::*__f)(_A0) volatile, _T1& __t1, _A0& __a0)
-{
-    return (__t1.*__f)(__a0);
-}
-
-template <class _Rp, class _Tp, class _T1, class _A0, class _A1>
-inline _LIBCPP_INLINE_VISIBILITY
-typename enable_if
-<
-    is_base_of<_Tp, typename remove_reference<_T1>::type>::value,
-    _Rp
->::type
-__invoke(_Rp (_Tp::*__f)(_A0, _A1) volatile, _T1& __t1, _A0& __a0, _A1& __a1)
-{
-    return (__t1.*__f)(__a0, __a1);
-}
-
-template <class _Rp, class _Tp, class _T1, class _A0, class _A1, class _A2>
-inline _LIBCPP_INLINE_VISIBILITY
-typename enable_if
-<
-    is_base_of<_Tp, typename remove_reference<_T1>::type>::value,
-    _Rp
->::type
-__invoke(_Rp (_Tp::*__f)(_A0, _A1, _A2) volatile, _T1& __t1, _A0& __a0, _A1& __a1, _A2& __a2)
-{
-    return (__t1.*__f)(__a0, __a1, __a2);
-}
-
-template <class _Rp, class _Tp, class _T1>
-inline _LIBCPP_INLINE_VISIBILITY
-typename enable_if
-<
-    is_base_of<_Tp, typename remove_reference<_T1>::type>::value,
-    _Rp
->::type
-__invoke(_Rp (_Tp::*__f)() const volatile, _T1& __t1)
-{
-    return (__t1.*__f)();
-}
-
-template <class _Rp, class _Tp, class _T1, class _A0>
-inline _LIBCPP_INLINE_VISIBILITY
-typename enable_if
-<
-    is_base_of<_Tp, typename remove_reference<_T1>::type>::value,
-    _Rp
->::type
-__invoke(_Rp (_Tp::*__f)(_A0) const volatile, _T1& __t1, _A0& __a0)
-{
-    return (__t1.*__f)(__a0);
-}
-
-template <class _Rp, class _Tp, class _T1, class _A0, class _A1>
-inline _LIBCPP_INLINE_VISIBILITY
-typename enable_if
-<
-    is_base_of<_Tp, typename remove_reference<_T1>::type>::value,
-    _Rp
->::type
-__invoke(_Rp (_Tp::*__f)(_A0, _A1) const volatile, _T1& __t1, _A0& __a0, _A1& __a1)
-{
-    return (__t1.*__f)(__a0, __a1);
-}
-
-template <class _Rp, class _Tp, class _T1, class _A0, class _A1, class _A2>
-inline _LIBCPP_INLINE_VISIBILITY
-typename enable_if
-<
-    is_base_of<_Tp, typename remove_reference<_T1>::type>::value,
-    _Rp
->::type
-__invoke(_Rp (_Tp::*__f)(_A0, _A1, _A2) const volatile, _T1& __t1, _A0& __a0, _A1& __a1, _A2& __a2)
-{
-    return (__t1.*__f)(__a0, __a1, __a2);
-}
-
-// second bullet
-
-template <class _Rp, class _Tp, class _T1>
-inline _LIBCPP_INLINE_VISIBILITY
-typename enable_if
-<
-    !is_base_of<_Tp, typename remove_reference<_T1>::type>::value,
-    _Rp
->::type
-__invoke(_Rp (_Tp::*__f)(), _T1 __t1)
-{
+typename __enable_invoke<_Fn, _T1>::_Bullet2
+__invoke(_Fn __f, _T1& __t1) {
     return ((*__t1).*__f)();
 }
 
-template <class _Rp, class _Tp, class _T1, class _A0>
+template <class _Fn, class _T1, class _A0>
 inline _LIBCPP_INLINE_VISIBILITY
-typename enable_if
-<
-    !is_base_of<_Tp, typename remove_reference<_T1>::type>::value,
-    _Rp
->::type
-__invoke(_Rp (_Tp::*__f)(_A0), _T1 __t1, _A0& __a0)
-{
+typename __enable_invoke<_Fn, _T1>::_Bullet2
+__invoke(_Fn __f, _T1& __t1, _A0& __a0) {
     return ((*__t1).*__f)(__a0);
 }
 
-template <class _Rp, class _Tp, class _T1, class _A0, class _A1>
+template <class _Fn, class _T1, class _A0, class _A1>
 inline _LIBCPP_INLINE_VISIBILITY
-typename enable_if
-<
-    !is_base_of<_Tp, typename remove_reference<_T1>::type>::value,
-    _Rp
->::type
-__invoke(_Rp (_Tp::*__f)(_A0, _A1), _T1 __t1, _A0& __a0, _A1& __a1)
-{
+typename __enable_invoke<_Fn, _T1>::_Bullet2
+__invoke(_Fn __f, _T1& __t1, _A0& __a0, _A1& __a1) {
     return ((*__t1).*__f)(__a0, __a1);
 }
 
-template <class _Rp, class _Tp, class _T1, class _A0, class _A1, class _A2>
+template <class _Fn, class _T1, class _A0, class _A1, class _A2>
 inline _LIBCPP_INLINE_VISIBILITY
-typename enable_if
-<
-    !is_base_of<_Tp, typename remove_reference<_T1>::type>::value,
-    _Rp
->::type
-__invoke(_Rp (_Tp::*__f)(_A0, _A1, _A2), _T1 __t1, _A0& __a0, _A1& __a1, _A2& __a2)
-{
+typename __enable_invoke<_Fn, _T1>::_Bullet2
+__invoke(_Fn __f, _T1& __t1, _A0& __a0, _A1& __a1, _A2& __a2) {
     return ((*__t1).*__f)(__a0, __a1, __a2);
 }
 
-template <class _Rp, class _Tp, class _T1>
+template <class _Fn, class _T1>
 inline _LIBCPP_INLINE_VISIBILITY
-typename enable_if
-<
-    !is_base_of<_Tp, typename remove_reference<_T1>::type>::value,
-    _Rp
->::type
-__invoke(_Rp (_Tp::*__f)() const, _T1 __t1)
-{
-    return ((*__t1).*__f)();
-}
-
-template <class _Rp, class _Tp, class _T1, class _A0>
-inline _LIBCPP_INLINE_VISIBILITY
-typename enable_if
-<
-    !is_base_of<_Tp, typename remove_reference<_T1>::type>::value,
-    _Rp
->::type
-__invoke(_Rp (_Tp::*__f)(_A0) const, _T1 __t1, _A0& __a0)
-{
-    return ((*__t1).*__f)(__a0);
-}
-
-template <class _Rp, class _Tp, class _T1, class _A0, class _A1>
-inline _LIBCPP_INLINE_VISIBILITY
-typename enable_if
-<
-    !is_base_of<_Tp, typename remove_reference<_T1>::type>::value,
-    _Rp
->::type
-__invoke(_Rp (_Tp::*__f)(_A0, _A1) const, _T1 __t1, _A0& __a0, _A1& __a1)
-{
-    return ((*__t1).*__f)(__a0, __a1);
-}
-
-template <class _Rp, class _Tp, class _T1, class _A0, class _A1, class _A2>
-inline _LIBCPP_INLINE_VISIBILITY
-typename enable_if
-<
-    !is_base_of<_Tp, typename remove_reference<_T1>::type>::value,
-    _Rp
->::type
-__invoke(_Rp (_Tp::*__f)(_A0, _A1, _A2) const, _T1 __t1, _A0& __a0, _A1& __a1, _A2& __a2)
-{
-    return ((*__t1).*__f)(__a0, __a1, __a2);
-}
-
-template <class _Rp, class _Tp, class _T1>
-inline _LIBCPP_INLINE_VISIBILITY
-typename enable_if
-<
-    !is_base_of<_Tp, typename remove_reference<_T1>::type>::value,
-    _Rp
->::type
-__invoke(_Rp (_Tp::*__f)() volatile, _T1 __t1)
-{
-    return ((*__t1).*__f)();
-}
-
-template <class _Rp, class _Tp, class _T1, class _A0>
-inline _LIBCPP_INLINE_VISIBILITY
-typename enable_if
-<
-    !is_base_of<_Tp, typename remove_reference<_T1>::type>::value,
-    _Rp
->::type
-__invoke(_Rp (_Tp::*__f)(_A0) volatile, _T1 __t1, _A0& __a0)
-{
-    return ((*__t1).*__f)(__a0);
-}
-
-template <class _Rp, class _Tp, class _T1, class _A0, class _A1>
-inline _LIBCPP_INLINE_VISIBILITY
-typename enable_if
-<
-    !is_base_of<_Tp, typename remove_reference<_T1>::type>::value,
-    _Rp
->::type
-__invoke(_Rp (_Tp::*__f)(_A0, _A1) volatile, _T1 __t1, _A0& __a0, _A1& __a1)
-{
-    return ((*__t1).*__f)(__a0, __a1);
-}
-
-template <class _Rp, class _Tp, class _T1, class _A0, class _A1, class _A2>
-inline _LIBCPP_INLINE_VISIBILITY
-typename enable_if
-<
-    !is_base_of<_Tp, typename remove_reference<_T1>::type>::value,
-    _Rp
->::type
-__invoke(_Rp (_Tp::*__f)(_A0, _A1, _A2) volatile, _T1 __t1, _A0& __a0, _A1& __a1, _A2& __a2)
-{
-    return ((*__t1).*__f)(__a0, __a1, __a2);
-}
-
-template <class _Rp, class _Tp, class _T1>
-inline _LIBCPP_INLINE_VISIBILITY
-typename enable_if
-<
-    !is_base_of<_Tp, typename remove_reference<_T1>::type>::value,
-    _Rp
->::type
-__invoke(_Rp (_Tp::*__f)() const volatile, _T1 __t1)
-{
-    return ((*__t1).*__f)();
-}
-
-template <class _Rp, class _Tp, class _T1, class _A0>
-inline _LIBCPP_INLINE_VISIBILITY
-typename enable_if
-<
-    !is_base_of<_Tp, typename remove_reference<_T1>::type>::value,
-    _Rp
->::type
-__invoke(_Rp (_Tp::*__f)(_A0) const volatile, _T1 __t1, _A0& __a0)
-{
-    return ((*__t1).*__f)(__a0);
-}
-
-template <class _Rp, class _Tp, class _T1, class _A0, class _A1>
-inline _LIBCPP_INLINE_VISIBILITY
-typename enable_if
-<
-    !is_base_of<_Tp, typename remove_reference<_T1>::type>::value,
-    _Rp
->::type
-__invoke(_Rp (_Tp::*__f)(_A0, _A1) const volatile, _T1 __t1, _A0& __a0, _A1& __a1)
-{
-    return ((*__t1).*__f)(__a0, __a1);
-}
-
-template <class _Rp, class _Tp, class _T1, class _A0, class _A1, class _A2>
-inline _LIBCPP_INLINE_VISIBILITY
-typename enable_if
-<
-    !is_base_of<_Tp, typename remove_reference<_T1>::type>::value,
-    _Rp
->::type
-__invoke(_Rp (_Tp::*__f)(_A0, _A1, _A2) const volatile, _T1 __t1, _A0& __a0, _A1& __a1, _A2& __a2)
-{
-    return ((*__t1).*__f)(__a0, __a1, __a2);
-}
-
-// third bullet
-
-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,
-   __apply_cv<_T1, _Rp>
->::type::type&
-__invoke(_Rp _Tp::* __f, _T1& __t1)
-{
+typename __enable_invoke<_Fn, _T1>::_Bullet3
+__invoke(_Fn __f, _T1& __t1) {
     return __t1.*__f;
 }
 
-
-// forth bullet
-
-template <class _T1, class _Rp, bool>
-struct __4th_helper
-{
-};
-
-template <class _T1, class _Rp>
-struct __4th_helper<_T1, _Rp, true>
-{
-    typedef typename __apply_cv<decltype(*_VSTD::declval<_T1&>()), _Rp>::type type;
-};
-
-template <class _Rp, class _Tp, class _T1>
+template <class _Fn, class _T1>
 inline _LIBCPP_INLINE_VISIBILITY
-typename __4th_helper<_T1, _Rp,
-    is_member_object_pointer<_Rp _Tp::*>::value &&
-    !is_base_of<_Tp, typename remove_reference<_T1>::type>::value
->::type&
-__invoke(_Rp _Tp::* __f, _T1& __t1)
-{
+typename __enable_invoke<_Fn, _T1>::_Bullet4
+__invoke(_Fn __f, _T1& __t1) {
     return (*__t1).*__f;
 }
 
@@ -488,29 +185,28 @@
     typedef decltype(__invoke(_VSTD::declval<_Fp&>())) type;
 };
 
-template <class _Tp, class _A0, bool = is_member_object_pointer<_Tp>::value>
+template <class _Tp, class _A0>
 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, true>
+struct __invoke_return0<_Rp _Tp::*, _A0>
 {
-    typedef typename __apply_cv<_A0, _Rp>::type& type;
-};
-
-template <class _Rp, class _Tp, class _A0>
-struct __invoke_return0<_Rp _Tp::*, _A0*, true>
-{
-    typedef typename __apply_cv<_A0, _Rp>::type& type;
+    typedef typename __enable_invoke<_Rp _Tp::*, _A0>::type type;
 };
 
 template <class _Tp, class _A0, class _A1>
 struct __invoke_return1
 {
     typedef decltype(__invoke(_VSTD::declval<_Tp&>(), _VSTD::declval<_A0&>(),
-                                                     _VSTD::declval<_A1&>())) type;
+                                                      _VSTD::declval<_A1&>())) type;
+};
+
+template <class _Rp, class _Class, class _A0, class _A1>
+struct __invoke_return1<_Rp _Class::*, _A0, _A1> {
+    typedef typename __enable_invoke<_Rp _Class::*, _A0>::type type;
 };
 
 template <class _Tp, class _A0, class _A1, class _A2>
@@ -521,4 +217,8 @@
                                                       _VSTD::declval<_A2&>())) type;
 };
 
+template <class _Ret, class _Class, class _A0, class _A1, class _A2>
+struct __invoke_return2<_Ret _Class::*, _A0, _A1, _A2> {
+    typedef typename __enable_invoke<_Ret _Class::*, _A0>::type type;
+};
 #endif  // _LIBCPP_FUNCTIONAL_BASE_03
diff --git a/include/functional b/include/functional
index 3c9f5a7..1328648 100644
--- a/include/functional
+++ b/include/functional
@@ -1262,22 +1262,102 @@
 #else
 
     template <class _A0>
+    _LIBCPP_INLINE_VISIBILITY
     typename __invoke_return0<type, _A0>::type
     operator() (_A0& __a0) const {
         return __invoke(__f_, __a0);
     }
 
+    template <class _A0>
+    _LIBCPP_INLINE_VISIBILITY
+    typename __invoke_return0<type, _A0 const>::type
+    operator() (_A0 const& __a0) const {
+        return __invoke(__f_, __a0);
+    }
+
     template <class _A0, class _A1>
+    _LIBCPP_INLINE_VISIBILITY
     typename __invoke_return1<type, _A0, _A1>::type
     operator() (_A0& __a0, _A1& __a1) const {
         return __invoke(__f_, __a0, __a1);
     }
 
+    template <class _A0, class _A1>
+    _LIBCPP_INLINE_VISIBILITY
+    typename __invoke_return1<type, _A0 const, _A1>::type
+    operator() (_A0 const& __a0, _A1& __a1) const {
+        return __invoke(__f_, __a0, __a1);
+    }
+
+    template <class _A0, class _A1>
+    _LIBCPP_INLINE_VISIBILITY
+    typename __invoke_return1<type, _A0, _A1 const>::type
+    operator() (_A0& __a0, _A1 const& __a1) const {
+        return __invoke(__f_, __a0, __a1);
+    }
+
+    template <class _A0, class _A1>
+    _LIBCPP_INLINE_VISIBILITY
+    typename __invoke_return1<type, _A0 const, _A1 const>::type
+    operator() (_A0 const& __a0, _A1 const& __a1) const {
+        return __invoke(__f_, __a0, __a1);
+    }
+
     template <class _A0, class _A1, class _A2>
+    _LIBCPP_INLINE_VISIBILITY
     typename __invoke_return2<type, _A0, _A1, _A2>::type
     operator() (_A0& __a0, _A1& __a1, _A2& __a2) const {
         return __invoke(__f_, __a0, __a1, __a2);
     }
+
+    template <class _A0, class _A1, class _A2>
+    _LIBCPP_INLINE_VISIBILITY
+    typename __invoke_return2<type, _A0 const, _A1, _A2>::type
+    operator() (_A0 const& __a0, _A1& __a1, _A2& __a2) const {
+        return __invoke(__f_, __a0, __a1, __a2);
+    }
+
+    template <class _A0, class _A1, class _A2>
+    _LIBCPP_INLINE_VISIBILITY
+    typename __invoke_return2<type, _A0, _A1 const, _A2>::type
+    operator() (_A0& __a0, _A1 const& __a1, _A2& __a2) const {
+        return __invoke(__f_, __a0, __a1, __a2);
+    }
+
+    template <class _A0, class _A1, class _A2>
+    _LIBCPP_INLINE_VISIBILITY
+    typename __invoke_return2<type, _A0, _A1, _A2 const>::type
+    operator() (_A0& __a0, _A1& __a1, _A2 const& __a2) const {
+        return __invoke(__f_, __a0, __a1, __a2);
+    }
+
+    template <class _A0, class _A1, class _A2>
+    _LIBCPP_INLINE_VISIBILITY
+    typename __invoke_return2<type, _A0 const, _A1 const, _A2>::type
+    operator() (_A0 const& __a0, _A1 const& __a1, _A2& __a2) const {
+        return __invoke(__f_, __a0, __a1, __a2);
+    }
+
+    template <class _A0, class _A1, class _A2>
+    _LIBCPP_INLINE_VISIBILITY
+    typename __invoke_return2<type, _A0 const, _A1, _A2 const>::type
+    operator() (_A0 const& __a0, _A1& __a1, _A2 const& __a2) const {
+        return __invoke(__f_, __a0, __a1, __a2);
+    }
+
+    template <class _A0, class _A1, class _A2>
+    _LIBCPP_INLINE_VISIBILITY
+    typename __invoke_return2<type, _A0, _A1 const, _A2 const>::type
+    operator() (_A0& __a0, _A1 const& __a1, _A2 const& __a2) const {
+        return __invoke(__f_, __a0, __a1, __a2);
+    }
+
+    template <class _A0, class _A1, class _A2>
+    _LIBCPP_INLINE_VISIBILITY
+    typename __invoke_return2<type, _A0 const, _A1 const, _A2 const>::type
+    operator() (_A0 const& __a0, _A1 const& __a1, _A2 const& __a2) const {
+        return __invoke(__f_, __a0, __a1, __a2);
+    }
 #endif
 };
 
diff --git a/test/std/utilities/function.objects/refwrap/refwrap.const/type_ctor.fail.cpp b/test/std/utilities/function.objects/refwrap/refwrap.const/type_ctor.fail.cpp
index ba46946..a231606 100644
--- a/test/std/utilities/function.objects/refwrap/refwrap.const/type_ctor.fail.cpp
+++ b/test/std/utilities/function.objects/refwrap/refwrap.const/type_ctor.fail.cpp
@@ -13,6 +13,8 @@
 
 // reference_wrapper(T&&) = delete;
 
+// XFAIL: c++98, c++03
+
 #include <functional>
 #include <cassert>
 
diff --git a/test/std/utilities/function.objects/refwrap/refwrap.helpers/ref_1.fail.cpp b/test/std/utilities/function.objects/refwrap/refwrap.helpers/ref_1.fail.cpp
index 86a5696..0aad498 100644
--- a/test/std/utilities/function.objects/refwrap/refwrap.helpers/ref_1.fail.cpp
+++ b/test/std/utilities/function.objects/refwrap/refwrap.helpers/ref_1.fail.cpp
@@ -15,6 +15,8 @@
 
 // Don't allow binding to a temp
 
+// XFAIL: c++98, c++03
+
 #include <functional>
 
 struct A {};