diff --git a/libcxx/include/variant b/libcxx/include/variant
--- a/libcxx/include/variant
+++ b/libcxx/include/variant
@@ -355,9 +355,9 @@
 
 enum class _Trait { _TriviallyAvailable, _Available, _Unavailable };
 
-template <class _Tp,
-          template <class> class _IsTriviallyAvailable,
-          template <class> class _IsAvailable>
+template <typename _Tp,
+          template <typename> class _IsTriviallyAvailable,
+          template <typename> class _IsAvailable>
 constexpr _Trait __trait =
     _IsTriviallyAvailable<_Tp>::value
         ? _Trait::_TriviallyAvailable
@@ -374,7 +374,7 @@
   return __result;
 }
 
-template <class... _Types>
+template <typename... _Types>
 struct __traits {
   static constexpr _Trait __copy_constructible_trait =
       __common_trait({__trait<_Types,
@@ -435,270 +435,183 @@
 
 namespace __visitation {
 
-#define _LIBCPP_VARIANT_CASES_4(_Case, _Base)                                  \
-  _Case(_Base + 0)                                                             \
-  _Case(_Base + 1)                                                             \
-  _Case(_Base + 2)                                                             \
-  _Case(_Base + 3)
-
-#define _LIBCPP_VARIANT_CASES_16(_Case, _Base)                                 \
-  _LIBCPP_VARIANT_CASES_4(_Case, _Base + 4 * 0)                                \
-  _LIBCPP_VARIANT_CASES_4(_Case, _Base + 4 * 1)                                \
-  _LIBCPP_VARIANT_CASES_4(_Case, _Base + 4 * 2)                                \
-  _LIBCPP_VARIANT_CASES_4(_Case, _Base + 4 * 3)
-
-#define _LIBCPP_VARIANT_CASES_64(_Case, _Base)                                 \
-  _LIBCPP_VARIANT_CASES_16(_Case, _Base + 16 * 0)                              \
-  _LIBCPP_VARIANT_CASES_16(_Case, _Base + 16 * 1)                              \
-  _LIBCPP_VARIANT_CASES_16(_Case, _Base + 16 * 2)                              \
-  _LIBCPP_VARIANT_CASES_16(_Case, _Base + 16 * 3)
-
-#define _LIBCPP_VARIANT_CASES_256(_Case, _Base)                                \
-  _LIBCPP_VARIANT_CASES_64(_Case, _Base + 64 * 0)                              \
-  _LIBCPP_VARIANT_CASES_64(_Case, _Base + 64 * 1)                              \
-  _LIBCPP_VARIANT_CASES_64(_Case, _Base + 64 * 2)                              \
-  _LIBCPP_VARIANT_CASES_64(_Case, _Base + 64 * 3)
-
-#define _LIBCPP_VARIANT_CASES(_NumCases, _Case)                                \
-  _LIBCPP_CONCAT(_LIBCPP_VARIANT_CASES_, _NumCases)(_Case, 0)
-
-#define _LIBCPP_VARIANT_SWITCH_MAX 256
-
-template <class _Iter, class _Fp, size_t... _Is>
-inline _LIBCPP_INLINE_VISIBILITY
-static constexpr void __fill_cartesian_impl(
-    _Iter __iter, _Fp __f, index_sequence<_Is...>) {
-  *__iter = __f(integral_constant<size_t, _Is>{}...);
-}
-
-template <class _Iter, class _Fp, size_t... _Is, size_t... _Js, class... _Ls>
-inline _LIBCPP_INLINE_VISIBILITY
-static constexpr void __fill_cartesian_impl(
-    _Iter __iter, _Fp __f, index_sequence<_Is...>, index_sequence<_Js...>, _Ls... __ls) {
-  constexpr size_t _Mp = (1 * ... * _Ls::size());
-  (__fill_cartesian_impl(
-      __iter + _Js * _Mp, __f, index_sequence<_Is..., _Js>{}, __ls...), ...);
-}
-
-template <size_t... _Ns, class _Iter, class _Fp>
-inline _LIBCPP_INLINE_VISIBILITY
-static constexpr void __fill_cartesian(_Iter __iter, _Fp __f) {
-  __fill_cartesian_impl(
-      __iter, __f, index_sequence<>{}, make_index_sequence<_Ns>{}...);
-}
-
-template <size_t _Np, size_t... _Ns>
-struct __multi {
+struct __base {
+  template <class _Visitor, class... _Vs>
   inline _LIBCPP_INLINE_VISIBILITY
-  static constexpr size_t __size = (_Np * ... * _Ns);
+  static constexpr decltype(auto)
+  __visit_alt_at(size_t __index, _Visitor&& __visitor, _Vs&&... __vs) {
+    constexpr auto __fdiagonal =
+        __make_fdiagonal<_Visitor&&,
+                         decltype(_VSTD::forward<_Vs>(__vs).__as_base())...>();
+    return __fdiagonal[__index](_VSTD::forward<_Visitor>(__visitor),
+                                _VSTD::forward<_Vs>(__vs).__as_base()...);
+  }
 
+  template <class _Visitor, class... _Vs>
   inline _LIBCPP_INLINE_VISIBILITY
-  static constexpr size_t
-  __index(const size_t (&__is)[sizeof...(_Ns) + 1]) noexcept {
-    constexpr size_t __ns[] = {_Ns..., 1};
-    size_t __result = 0;
-    for (size_t __i = 0; __i < sizeof...(_Ns) + 1; ++__i) {
-      if (__is[__i] == variant_npos) {
-        return variant_npos;
-      }
-      __result += __is[__i];
-      __result *= __ns[__i];
-    }
-    return __result;
+  static constexpr decltype(auto) __visit_alt(_Visitor&& __visitor,
+                                              _Vs&&... __vs) {
+    constexpr auto __fmatrix =
+        __make_fmatrix<_Visitor&&,
+                       decltype(_VSTD::forward<_Vs>(__vs).__as_base())...>();
+    return __at(__fmatrix, __vs.index()...)(
+        _VSTD::forward<_Visitor>(__visitor),
+        _VSTD::forward<_Vs>(__vs).__as_base()...);
   }
-};
 
-template <size_t... _Ns>
-struct __indices {
+private:
+  template <class _Tp>
   inline _LIBCPP_INLINE_VISIBILITY
-  static constexpr auto __value = [] {
-    using _Tp = array<size_t, sizeof...(_Ns)>;
-    array<_Tp, (1 * ... * _Ns)> __result = {};
-    __fill_cartesian<_Ns...>(__result.begin(),
-                             [](auto... __is) -> _Tp { return {__is...}; });
-    return __result;
-  }();
-};
+  static constexpr const _Tp& __at(const _Tp& __elem) { return __elem; }
 
-template <size_t... _Ns, class _Fp, class _Rp, class... _Args>
-inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS
-static constexpr auto __make_vtable_impl(_Fp __f, _Rp (*)(_Args...)) {
-  array<_Rp (*)(_Args...), (1 * ... * _Ns) + 1> __result = {
-      [](_Args...) -> _Rp { __throw_bad_variant_access(); }
-  };
-  __fill_cartesian<_Ns...>(__result.begin() + 1, __f);
-  return __result;
-}
+  template <class _Tp, size_t _Np, typename... _Indices>
+  inline _LIBCPP_INLINE_VISIBILITY
+  static constexpr auto&& __at(const array<_Tp, _Np>& __elems,
+                               size_t __index, _Indices... __indices) {
+    return __at(__elems[__index], __indices...);
+  }
 
-template <size_t... _Ns, class _Fp>
-inline _LIBCPP_INLINE_VISIBILITY
-static constexpr auto __make_vtable(_Fp __f) {
-  using _Tp = decltype(__f(integral_constant<size_t, (_Ns, 0)>{}...));
-  return __make_vtable_impl<_Ns...>(__f, _Tp{});
-}
+  template <class _Fp, class... _Fs>
+  static constexpr void __std_visit_visitor_return_type_check() {
+    static_assert(
+        __all<is_same_v<_Fp, _Fs>...>::value,
+        "`std::visit` requires the visitor to have a single return type.");
+  }
 
-struct __base {
-  template <class _Vis, class... _Vs>
-  struct __dispatch {
-    template <size_t... _Is>
+  template <class... _Fs>
+  inline _LIBCPP_INLINE_VISIBILITY
+  static constexpr auto __make_farray(_Fs&&... __fs) {
+    __std_visit_visitor_return_type_check<__uncvref_t<_Fs>...>();
+    using __result = array<common_type_t<__uncvref_t<_Fs>...>, sizeof...(_Fs)>;
+    return __result{{_VSTD::forward<_Fs>(__fs)...}};
+  }
+
+  template <std::size_t... _Is>
+  struct __dispatcher {
+    template <class _Fp, class... _Vs>
     inline _LIBCPP_INLINE_VISIBILITY
-    constexpr auto operator()(integral_constant<size_t, _Is>...) const noexcept {
-      return +[](_Vis&& __vis, _Vs&&... __vs) -> decltype(auto) {
+    static constexpr decltype(auto) __dispatch(_Fp __f, _Vs... __vs) {
         return __invoke_constexpr(
-            _VSTD::forward<_Vis>(__vis),
-            __access::__base::__get_alt<_Is>(_VSTD::forward<_Vs>(__vs))...);
-      };
+            static_cast<_Fp>(__f),
+            __access::__base::__get_alt<_Is>(static_cast<_Vs>(__vs))...);
     }
   };
 
-  template <class _Vis, class _Vp, class _Wp>
-  inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS
-  static constexpr decltype(auto)
-  __visit_alt_at(size_t __index, _Vis&& __vis, _Vp&& __v, _Wp&& __w) {
-    constexpr size_t __size = __uncvref_t<_Vp>::__size();
-    static_assert(__size == __uncvref_t<_Wp>::__size());
-    constexpr auto __dispatch_at = [](auto __i) {
-      return __dispatch<_Vis, _Vp, _Wp>{}(__i, __i);
-    };
-#define _LIBCPP_VARIANT_CASE(_Ip)                                              \
-  case _Ip: {                                                                  \
-    if constexpr (_Ip < __size) {                                              \
-      return __dispatch_at(integral_constant<size_t, _Ip>{})(                  \
-          _VSTD::forward<_Vis>(__vis),                                         \
-          _VSTD::forward<_Vp>(__v),                                            \
-          _VSTD::forward<_Wp>(__w));                                           \
-    } else {                                                                   \
-      _LIBCPP_UNREACHABLE();                                                   \
-    }                                                                          \
+  template <class _Fp, class... _Vs, size_t... _Is>
+  inline _LIBCPP_INLINE_VISIBILITY
+  static constexpr auto __make_dispatch(index_sequence<_Is...>) {
+    return __dispatcher<_Is...>::template __dispatch<_Fp, _Vs...>;
   }
-    if constexpr (__size <= _LIBCPP_VARIANT_SWITCH_MAX) {
-      switch (__index) {
-        _LIBCPP_VARIANT_CASES(_LIBCPP_VARIANT_SWITCH_MAX, _LIBCPP_VARIANT_CASE)
-        default: __throw_bad_variant_access();
-      }
-    } else {
-      constexpr auto __vtable = __make_vtable<__size>(__dispatch_at);
-      return __vtable[__index + 1](_VSTD::forward<_Vis>(__vis),
-                                   _VSTD::forward<_Vp>(__v),
-                                   _VSTD::forward<_Wp>(__w));
-    }
-#undef _LIBCPP_VARIANT_CASE
+
+  template <size_t _Ip, class _Fp, class... _Vs>
+  inline _LIBCPP_INLINE_VISIBILITY
+  static constexpr auto __make_fdiagonal_impl() {
+    return __make_dispatch<_Fp, _Vs...>(
+        index_sequence<(__identity<_Vs>{}, _Ip)...>{});
   }
 
-  template <size_t... _Is, class _Vis, class... _Vs>
+  template <class _Fp, class... _Vs, size_t... _Is>
   inline _LIBCPP_INLINE_VISIBILITY
-  static constexpr decltype(auto) __visit_alt(_Vis&& __vis, _Vs&&... __vs) {
-    if constexpr (sizeof...(_Vs) == 0) {
-      return __invoke_constexpr(_VSTD::forward<_Vis>(__vis));
-    } else {
-      return __visit_alt_impl(index_sequence_for<_Vs...>{},
-                              _VSTD::forward<_Vis>(__vis),
-                              _VSTD::forward<_Vs>(__vs)...);
-    }
+  static constexpr auto __make_fdiagonal_impl(index_sequence<_Is...>) {
+    return __base::__make_farray(__make_fdiagonal_impl<_Is, _Fp, _Vs...>()...);
   }
 
-  template <size_t... _Is, class _Vis, class... _Vs>
-  inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS
-  static constexpr decltype(auto)
-  __visit_alt_impl(index_sequence<_Is...>, _Vis&& __vis, _Vs&&... __vs) {
-    using __multi = __multi<__uncvref_t<_Vs>::__size()...>;
-    constexpr __dispatch<_Vis, _Vs...> __dispatch;
-#define _LIBCPP_VARIANT_CASE(_Ip)                                              \
-  case _Ip: {                                                                  \
-    if constexpr (_Ip < __multi::__size) {                                     \
-      return __dispatch(integral_constant<size_t, __itable[_Ip][_Is]>{}...)(   \
-          _VSTD::forward<_Vis>(__vis), _VSTD::forward<_Vs>(__vs)...);          \
-    } else {                                                                   \
-      _LIBCPP_UNREACHABLE();                                                   \
-    }                                                                          \
+  template <class _Fp, class _Vp, class... _Vs>
+  inline _LIBCPP_INLINE_VISIBILITY
+  static constexpr auto __make_fdiagonal() {
+    constexpr size_t _Np = __uncvref_t<_Vp>::__size();
+    static_assert(__all<(_Np == __uncvref_t<_Vs>::__size())...>::value);
+    return __make_fdiagonal_impl<_Fp, _Vp, _Vs...>(make_index_sequence<_Np>{});
   }
-    if constexpr (__multi::__size <= _LIBCPP_VARIANT_SWITCH_MAX) {
-      constexpr const auto& __itable =
-          __indices<__uncvref_t<_Vs>::__size()...>::__value;
-      switch (__multi::__index({__vs.index()...})) {
-        _LIBCPP_VARIANT_CASES(_LIBCPP_VARIANT_SWITCH_MAX, _LIBCPP_VARIANT_CASE)
-        default: __throw_bad_variant_access();
-      }
-    } else {
-      constexpr auto __vtable =
-          __make_vtable<__uncvref_t<_Vs>::__size()...>(__dispatch);
-      return __vtable[__multi::__index({__vs.index()...}) + 1](
-          _VSTD::forward<_Vis>(__vis), _VSTD::forward<_Vs>(__vs)...);
-    }
-#undef _LIBCPP_VARIANT_CASE
+
+  template <class _Fp, class... _Vs, size_t... _Is>
+  inline _LIBCPP_INLINE_VISIBILITY
+  static constexpr auto __make_fmatrix_impl(index_sequence<_Is...> __is) {
+    return __make_dispatch<_Fp, _Vs...>(__is);
+  }
+
+  template <class _Fp, class... _Vs, size_t... _Is, size_t... _Js, class... _Ls>
+  inline _LIBCPP_INLINE_VISIBILITY
+  static constexpr auto __make_fmatrix_impl(index_sequence<_Is...>,
+                                            index_sequence<_Js...>,
+                                            _Ls... __ls) {
+    return __base::__make_farray(__make_fmatrix_impl<_Fp, _Vs...>(
+        index_sequence<_Is..., _Js>{}, __ls...)...);
+  }
+
+  template <class _Fp, class... _Vs>
+  inline _LIBCPP_INLINE_VISIBILITY
+  static constexpr auto __make_fmatrix() {
+    return __make_fmatrix_impl<_Fp, _Vs...>(
+        index_sequence<>{}, make_index_sequence<__uncvref_t<_Vs>::__size()>{}...);
   }
 };
 
 struct __variant {
-  template <class _Vis, class _Vp, class _Wp>
+  template <class _Visitor, class... _Vs>
   inline _LIBCPP_INLINE_VISIBILITY
   static constexpr decltype(auto)
-  __visit_alt_at(size_t __index, _Vis&& __vis, _Vp&& __v, _Wp&& __w) {
+  __visit_alt_at(size_t __index, _Visitor&& __visitor, _Vs&&... __vs) {
     return __base::__visit_alt_at(__index,
-                                  _VSTD::forward<_Vis>(__vis),
-                                  _VSTD::forward<_Vp>(__v).__impl,
-                                  _VSTD::forward<_Wp>(__w).__impl);
+                                  _VSTD::forward<_Visitor>(__visitor),
+                                  _VSTD::forward<_Vs>(__vs).__impl...);
   }
 
-  template <class _Vis, class... _Vs>
+  template <class _Visitor, class... _Vs>
   inline _LIBCPP_INLINE_VISIBILITY
-  static constexpr decltype(auto) __visit_alt(_Vis&& __vis, _Vs&&... __vs) {
-    return __base::__visit_alt(_VSTD::forward<_Vis>(__vis),
+  static constexpr decltype(auto) __visit_alt(_Visitor&& __visitor,
+                                              _Vs&&... __vs) {
+    return __base::__visit_alt(_VSTD::forward<_Visitor>(__visitor),
                                _VSTD::forward<_Vs>(__vs).__impl...);
   }
 
-  template <class _Vis, class _Vp, class _Wp>
+  template <class _Visitor, class... _Vs>
   inline _LIBCPP_INLINE_VISIBILITY
   static constexpr decltype(auto)
-  __visit_value_at(size_t __index, _Vis&& __vis, _Vp&& __v, _Wp&& __w) {
-    return __visit_alt_at(__index,
-                          __make_value_visitor(_VSTD::forward<_Vis>(__vis)),
-                          _VSTD::forward<_Vp>(__v),
-                          _VSTD::forward<_Wp>(__w));
+  __visit_value_at(size_t __index, _Visitor&& __visitor, _Vs&&... __vs) {
+    return __visit_alt_at(
+        __index,
+        __make_value_visitor(_VSTD::forward<_Visitor>(__visitor)),
+        _VSTD::forward<_Vs>(__vs)...);
   }
 
-  template <class _Vis, class... _Vs>
+  template <class _Visitor, class... _Vs>
   inline _LIBCPP_INLINE_VISIBILITY
-  static constexpr decltype(auto) __visit_value(_Vis&& __vis, _Vs&&... __vs) {
-    return __visit_alt(__make_value_visitor(_VSTD::forward<_Vis>(__vis)),
-                       _VSTD::forward<_Vs>(__vs)...);
+  static constexpr decltype(auto) __visit_value(_Visitor&& __visitor,
+                                                _Vs&&... __vs) {
+    return __visit_alt(
+        __make_value_visitor(_VSTD::forward<_Visitor>(__visitor)),
+        _VSTD::forward<_Vs>(__vs)...);
   }
 
 private:
-  template <class _Vis, class... _Values>
-  inline _LIBCPP_INLINE_VISIBILITY
+  template <class _Visitor, class... _Values>
   static constexpr void __std_visit_exhaustive_visitor_check() {
-    static_assert(is_invocable_v<_Vis, _Values...>,
+    static_assert(is_invocable_v<_Visitor, _Values...>,
                   "`std::visit` requires the visitor to be exhaustive.");
   }
 
-  template <class _Vis>
+  template <class _Visitor>
   struct __value_visitor {
     template <class... _Alts>
     inline _LIBCPP_INLINE_VISIBILITY
     constexpr decltype(auto) operator()(_Alts&&... __alts) const {
       __std_visit_exhaustive_visitor_check<
-          _Vis, decltype((_VSTD::forward<_Alts>(__alts).__value))...>();
-      return __invoke_constexpr(_VSTD::forward<_Vis>(__vis),
+          _Visitor,
+          decltype((_VSTD::forward<_Alts>(__alts).__value))...>();
+      return __invoke_constexpr(_VSTD::forward<_Visitor>(__visitor),
                                 _VSTD::forward<_Alts>(__alts).__value...);
     }
-    _Vis&& __vis;
+    _Visitor&& __visitor;
   };
 
-  template <class _Vis>
+  template <class _Visitor>
   inline _LIBCPP_INLINE_VISIBILITY
-  static constexpr auto __make_value_visitor(_Vis&& __vis) {
-    return __value_visitor<_Vis>{_VSTD::forward<_Vis>(__vis)};
+  static constexpr auto __make_value_visitor(_Visitor&& __visitor) {
+    return __value_visitor<_Visitor>{_VSTD::forward<_Visitor>(__visitor)};
   }
 };
 
-#undef _LIBCPP_VARIANT_SWITCH_MAX
-#undef _LIBCPP_VARIANT_CASES
-#undef _LIBCPP_VARIANT_CASES_256
-#undef _LIBCPP_VARIANT_CASES_64
-#undef _LIBCPP_VARIANT_CASES_16
-#undef _LIBCPP_VARIANT_CASES_4
-
 } // namespace __visitation
 
 template <size_t _Index, class _Tp>
@@ -721,7 +634,7 @@
 
 #define _LIBCPP_VARIANT_UNION(destructible_trait, destructor)                  \
   template <size_t _Index, class _Tp, class... _Types>                         \
-  union _LIBCPP_TEMPLATE_VIS __union<destructible_trait,                       \
+  union _LIBCPP_TEMPLATE_VIS __union<destructible_trait,                      \
                                       _Index,                                  \
                                       _Tp,                                     \
                                       _Types...> {                             \
@@ -875,9 +788,9 @@
   template <size_t _Ip, class _Tp, class... _Args>
   inline _LIBCPP_INLINE_VISIBILITY
   static _Tp& __construct_alt(__alt<_Ip, _Tp>& __a, _Args&&... __args) {
-    auto* __result = ::new ((void*)_VSTD::addressof(__a))
+    ::new ((void*)_VSTD::addressof(__a))
         __alt<_Ip, _Tp>(in_place, _VSTD::forward<_Args>(__args)...);
-    return __result->__value;
+    return __a.__value;
   }
 
   template <class _Rhs>
@@ -944,7 +857,7 @@
 #define _LIBCPP_VARIANT_COPY_CONSTRUCTOR(copy_constructible_trait,             \
                                          copy_constructor)                     \
   template <class... _Types>                                                   \
-  class _LIBCPP_TEMPLATE_VIS __copy_constructor<__traits<_Types...>,           \
+  class _LIBCPP_TEMPLATE_VIS __copy_constructor<__traits<_Types...>,          \
                                                  copy_constructible_trait>     \
       : public __move_constructor<__traits<_Types...>> {                       \
     using __base_type = __move_constructor<__traits<_Types...>>;               \
@@ -990,7 +903,7 @@
   auto& __emplace(_Args&&... __args) {
     this->__destroy();
     auto& __res = this->__construct_alt(__access::__base::__get_alt<_Ip>(*this),
-                                        _VSTD::forward<_Args>(__args)...);
+                          _VSTD::forward<_Args>(__args)...);
     this->__index = _Ip;
     return __res;
   }
@@ -1043,7 +956,7 @@
 #define _LIBCPP_VARIANT_MOVE_ASSIGNMENT(move_assignable_trait,                 \
                                         move_assignment)                       \
   template <class... _Types>                                                   \
-  class _LIBCPP_TEMPLATE_VIS __move_assignment<__traits<_Types...>,            \
+  class _LIBCPP_TEMPLATE_VIS __move_assignment<__traits<_Types...>,           \
                                                 move_assignable_trait>         \
       : public __assignment<__traits<_Types...>> {                             \
     using __base_type = __assignment<__traits<_Types...>>;                     \
@@ -1084,7 +997,7 @@
 #define _LIBCPP_VARIANT_COPY_ASSIGNMENT(copy_assignable_trait,                 \
                                         copy_assignment)                       \
   template <class... _Types>                                                   \
-  class _LIBCPP_TEMPLATE_VIS __copy_assignment<__traits<_Types...>,            \
+  class _LIBCPP_TEMPLATE_VIS __copy_assignment<__traits<_Types...>,           \
                                                 copy_assignable_trait>         \
       : public __move_assignment<__traits<_Types...>> {                        \
     using __base_type = __move_assignment<__traits<_Types...>>;                \
@@ -1678,12 +1591,18 @@
       __lhs.index(), __convert_to_bool<greater_equal<>>{}, __lhs, __rhs);
 }
 
-template <class _Vis, class... _Vs>
+template <class _Visitor, class... _Vs>
 inline _LIBCPP_INLINE_VISIBILITY
 _LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS
-constexpr decltype(auto) visit(_Vis&& __vis, _Vs&&... __vs) {
+constexpr decltype(auto) visit(_Visitor&& __visitor, _Vs&&... __vs) {
   using __variant_detail::__visitation::__variant;
-  return __variant::__visit_value(_VSTD::forward<_Vis>(__vis),
+  bool __results[] = {__vs.valueless_by_exception()...};
+  for (bool __result : __results) {
+    if (__result) {
+      __throw_bad_variant_access();
+    }
+  }
+  return __variant::__visit_value(_VSTD::forward<_Visitor>(__visitor),
                                   _VSTD::forward<_Vs>(__vs)...);
 }
 
diff --git a/libcxx/test/std/utilities/variant/variant.hash/hash.pass.cpp b/libcxx/test/std/utilities/variant/variant.hash/hash.pass.cpp
--- a/libcxx/test/std/utilities/variant/variant.hash/hash.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.hash/hash.pass.cpp
@@ -9,12 +9,6 @@
 
 // UNSUPPORTED: c++03, c++11, c++14
 
-// Throwing bad_variant_access is supported starting in macosx10.13
-// XFAIL: with_system_cxx_lib=macosx10.12 && !no-exceptions
-// XFAIL: with_system_cxx_lib=macosx10.11 && !no-exceptions
-// XFAIL: with_system_cxx_lib=macosx10.10 && !no-exceptions
-// XFAIL: with_system_cxx_lib=macosx10.9 && !no-exceptions
-
 // <variant>
 
 // template <class... Types> struct hash<variant<Types...>>;
diff --git a/libcxx/test/std/utilities/variant/variant.relops/relops.pass.cpp b/libcxx/test/std/utilities/variant/variant.relops/relops.pass.cpp
--- a/libcxx/test/std/utilities/variant/variant.relops/relops.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.relops/relops.pass.cpp
@@ -9,12 +9,6 @@
 
 // UNSUPPORTED: c++03, c++11, c++14
 
-// Throwing bad_variant_access is supported starting in macosx10.13
-// XFAIL: with_system_cxx_lib=macosx10.12 && !no-exceptions
-// XFAIL: with_system_cxx_lib=macosx10.11 && !no-exceptions
-// XFAIL: with_system_cxx_lib=macosx10.10 && !no-exceptions
-// XFAIL: with_system_cxx_lib=macosx10.9 && !no-exceptions
-
 // <variant>
 
 // template <class ...Types>
diff --git a/libcxx/test/std/utilities/variant/variant.relops/relops_bool_conv.fail.cpp b/libcxx/test/std/utilities/variant/variant.relops/relops_bool_conv.fail.cpp
--- a/libcxx/test/std/utilities/variant/variant.relops/relops_bool_conv.fail.cpp
+++ b/libcxx/test/std/utilities/variant/variant.relops/relops_bool_conv.fail.cpp
@@ -9,12 +9,6 @@
 
 // UNSUPPORTED: c++03, c++11, c++14
 
-// Throwing bad_variant_access is supported starting in macosx10.13
-// XFAIL: with_system_cxx_lib=macosx10.12 && !no-exceptions
-// XFAIL: with_system_cxx_lib=macosx10.11 && !no-exceptions
-// XFAIL: with_system_cxx_lib=macosx10.10 && !no-exceptions
-// XFAIL: with_system_cxx_lib=macosx10.9 && !no-exceptions
-
 // <variant>
 
 // template <class ...Types>
diff --git a/libcxx/test/std/utilities/variant/variant.variant/variant.dtor/dtor.pass.cpp b/libcxx/test/std/utilities/variant/variant.variant/variant.dtor/dtor.pass.cpp
--- a/libcxx/test/std/utilities/variant/variant.variant/variant.dtor/dtor.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.variant/variant.dtor/dtor.pass.cpp
@@ -9,12 +9,6 @@
 
 // UNSUPPORTED: c++03, c++11, c++14
 
-// Throwing bad_variant_access is supported starting in macosx10.13
-// XFAIL: with_system_cxx_lib=macosx10.12 && !no-exceptions
-// XFAIL: with_system_cxx_lib=macosx10.11 && !no-exceptions
-// XFAIL: with_system_cxx_lib=macosx10.10 && !no-exceptions
-// XFAIL: with_system_cxx_lib=macosx10.9 && !no-exceptions
-
 // <variant>
 
 // template <class ...Types> class variant;
diff --git a/libcxx/test/std/utilities/variant/variant.variant/variant.status/index.pass.cpp b/libcxx/test/std/utilities/variant/variant.variant/variant.status/index.pass.cpp
--- a/libcxx/test/std/utilities/variant/variant.variant/variant.status/index.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.variant/variant.status/index.pass.cpp
@@ -9,12 +9,6 @@
 
 // UNSUPPORTED: c++03, c++11, c++14
 
-// Throwing bad_variant_access is supported starting in macosx10.13
-// XFAIL: with_system_cxx_lib=macosx10.12 && !no-exceptions
-// XFAIL: with_system_cxx_lib=macosx10.11 && !no-exceptions
-// XFAIL: with_system_cxx_lib=macosx10.10 && !no-exceptions
-// XFAIL: with_system_cxx_lib=macosx10.9 && !no-exceptions
-
 // <variant>
 
 // template <class ...Types> class variant;
diff --git a/libcxx/test/std/utilities/variant/variant.variant/variant.status/valueless_by_exception.pass.cpp b/libcxx/test/std/utilities/variant/variant.variant/variant.status/valueless_by_exception.pass.cpp
--- a/libcxx/test/std/utilities/variant/variant.variant/variant.status/valueless_by_exception.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.variant/variant.status/valueless_by_exception.pass.cpp
@@ -9,12 +9,6 @@
 
 // UNSUPPORTED: c++03, c++11, c++14
 
-// Throwing bad_variant_access is supported starting in macosx10.13
-// XFAIL: with_system_cxx_lib=macosx10.12 && !no-exceptions
-// XFAIL: with_system_cxx_lib=macosx10.11 && !no-exceptions
-// XFAIL: with_system_cxx_lib=macosx10.10 && !no-exceptions
-// XFAIL: with_system_cxx_lib=macosx10.9 && !no-exceptions
-
 // <variant>
 
 // template <class ...Types> class variant;