diff --git a/libcxx/include/__hash_table b/libcxx/include/__hash_table
index 1feb4bc3582f6..4e615d4fac018 100644
--- a/libcxx/include/__hash_table
+++ b/libcxx/include/__hash_table
@@ -34,19 +34,17 @@ _LIBCPP_BEGIN_NAMESPACE_STD
 template <class _Key, class _Tp>
 struct __hash_value_type;
 
-#ifndef _LIBCPP_CXX03_LANG
 template <class _Tp>
 struct __is_hash_value_type_imp : false_type {};
 
 template <class _Key, class _Value>
-struct __is_hash_value_type_imp<__hash_value_type<_Key, _Value>> : true_type {};
+struct __is_hash_value_type_imp<__hash_value_type<_Key, _Value> > : true_type {};
 
 template <class ..._Args>
 struct __is_hash_value_type : false_type {};
 
 template <class _One>
 struct __is_hash_value_type<_One> : __is_hash_value_type_imp<typename __uncvref<_One>::type> {};
-#endif
 
 _LIBCPP_FUNC_VIS
 size_t __next_prime(size_t __n);
@@ -155,12 +153,10 @@ struct __hash_key_value_types {
   static __container_value_type* __get_ptr(__node_value_type& __n) {
     return _VSTD::addressof(__n);
   }
-#ifndef _LIBCPP_CXX03_LANG
   _LIBCPP_INLINE_VISIBILITY
   static __container_value_type&& __move(__node_value_type& __v) {
     return _VSTD::move(__v);
   }
-#endif
 };
 
 template <class _Key, class _Tp>
@@ -197,13 +193,10 @@ struct __hash_key_value_types<__hash_value_type<_Key, _Tp> > {
   static __container_value_type* __get_ptr(__node_value_type& __n) {
     return _VSTD::addressof(__n.__get_value());
   }
-#ifndef _LIBCPP_CXX03_LANG
   _LIBCPP_INLINE_VISIBILITY
   static pair<key_type&&, mapped_type&&> __move(__node_value_type& __v) {
     return __v.__move();
   }
-#endif
-
 };
 
 template <class _Tp, class _AllocPtr, class _KVTypes = __hash_key_value_types<_Tp>,
@@ -795,7 +788,6 @@ public:
         _NOEXCEPT_(is_nothrow_copy_constructible<allocator_type>::value)
         : __data_(__size, __a) {}
 
-#ifndef _LIBCPP_CXX03_LANG
     _LIBCPP_INLINE_VISIBILITY
     __bucket_list_deallocator(__bucket_list_deallocator&& __x)
         _NOEXCEPT_(is_nothrow_move_constructible<allocator_type>::value)
@@ -803,7 +795,6 @@ public:
     {
         __x.size() = 0;
     }
-#endif
 
     _LIBCPP_INLINE_VISIBILITY
     size_type& size() _NOEXCEPT {return __data_.first();}
@@ -1019,7 +1010,6 @@ public:
     explicit __hash_table(const allocator_type& __a);
     __hash_table(const __hash_table& __u);
     __hash_table(const __hash_table& __u, const allocator_type& __a);
-#ifndef _LIBCPP_CXX03_LANG
     __hash_table(__hash_table&& __u)
         _NOEXCEPT_(
             is_nothrow_move_constructible<__bucket_list>::value &&
@@ -1028,11 +1018,9 @@ public:
             is_nothrow_move_constructible<hasher>::value &&
             is_nothrow_move_constructible<key_equal>::value);
     __hash_table(__hash_table&& __u, const allocator_type& __a);
-#endif  // _LIBCPP_CXX03_LANG
     ~__hash_table();
 
     __hash_table& operator=(const __hash_table& __u);
-#ifndef _LIBCPP_CXX03_LANG
     _LIBCPP_INLINE_VISIBILITY
     __hash_table& operator=(__hash_table&& __u)
         _NOEXCEPT_(
@@ -1040,7 +1028,6 @@ public:
             is_nothrow_move_assignable<__node_allocator>::value &&
             is_nothrow_move_assignable<hasher>::value &&
             is_nothrow_move_assignable<key_equal>::value);
-#endif
     template <class _InputIterator>
         void __assign_unique(_InputIterator __first, _InputIterator __last);
     template <class _InputIterator>
@@ -1078,7 +1065,6 @@ public:
     iterator             __node_insert_multi(const_iterator __p,
                                              __node_pointer __nd);
 
-#ifndef _LIBCPP_CXX03_LANG
     template <class _Key, class ..._Args>
     _LIBCPP_INLINE_VISIBILITY
     pair<iterator, bool> __emplace_unique_key_args(_Key const& __k, _Args&&... __args);
@@ -1163,15 +1149,6 @@ public:
         return __emplace_hint_multi(__p, _VSTD::forward<_Pp>(__x));
     }
 
-#else  // !defined(_LIBCPP_CXX03_LANG)
-    template <class _Key, class _Args>
-    _LIBCPP_INLINE_VISIBILITY
-    pair<iterator, bool> __emplace_unique_key_args(_Key const&, _Args& __args);
-
-    iterator __insert_multi(const __container_value_type& __x);
-    iterator __insert_multi(const_iterator __p, const __container_value_type& __x);
-#endif
-
     _LIBCPP_INLINE_VISIBILITY
     pair<iterator, bool> __insert_unique(const __container_value_type& __x) {
         return __emplace_unique_key_args(_NodeTypes::__get_key(__x), __x);
@@ -1365,16 +1342,11 @@ public:
 private:
     void __rehash(size_type __n);
 
-#ifndef _LIBCPP_CXX03_LANG
     template <class ..._Args>
     __node_holder __construct_node(_Args&& ...__args);
 
     template <class _First, class ..._Rest>
     __node_holder __construct_node_hash(size_t __hash, _First&& __f, _Rest&&... __rest);
-#else // _LIBCPP_CXX03_LANG
-    __node_holder __construct_node(const __container_value_type& __v);
-    __node_holder __construct_node_hash(size_t __hash, const __container_value_type& __v);
-#endif
 
 
     _LIBCPP_INLINE_VISIBILITY
@@ -1385,7 +1357,6 @@ private:
     _LIBCPP_INLINE_VISIBILITY
         void __copy_assign_alloc(const __hash_table&, false_type) {}
 
-#ifndef _LIBCPP_CXX03_LANG
     void __move_assign(__hash_table& __u, false_type);
     void __move_assign(__hash_table& __u, true_type)
         _NOEXCEPT_(
@@ -1412,7 +1383,6 @@ private:
     }
     _LIBCPP_INLINE_VISIBILITY
         void __move_assign_alloc(__hash_table&, false_type) _NOEXCEPT {}
-#endif // _LIBCPP_CXX03_LANG
 
     void __deallocate_node(__next_pointer __np) _NOEXCEPT;
     __next_pointer __detach() _NOEXCEPT;
@@ -1489,8 +1459,6 @@ __hash_table<_Tp, _Hash, _Equal, _Alloc>::__hash_table(const __hash_table& __u,
 {
 }
 
-#ifndef _LIBCPP_CXX03_LANG
-
 template <class _Tp, class _Hash, class _Equal, class _Alloc>
 __hash_table<_Tp, _Hash, _Equal, _Alloc>::__hash_table(__hash_table&& __u)
         _NOEXCEPT_(
@@ -1538,8 +1506,6 @@ __hash_table<_Tp, _Hash, _Equal, _Alloc>::__hash_table(__hash_table&& __u,
     }
 }
 
-#endif  // _LIBCPP_CXX03_LANG
-
 template <class _Tp, class _Hash, class _Equal, class _Alloc>
 __hash_table<_Tp, _Hash, _Equal, _Alloc>::~__hash_table()
 {
@@ -1630,8 +1596,6 @@ __hash_table<_Tp, _Hash, _Equal, _Alloc>::__detach() _NOEXCEPT
     return __cache;
 }
 
-#ifndef _LIBCPP_CXX03_LANG
-
 template <class _Tp, class _Hash, class _Equal, class _Alloc>
 void
 __hash_table<_Tp, _Hash, _Equal, _Alloc>::__move_assign(
@@ -1726,8 +1690,6 @@ __hash_table<_Tp, _Hash, _Equal, _Alloc>::operator=(__hash_table&& __u)
     return *this;
 }
 
-#endif  // _LIBCPP_CXX03_LANG
-
 template <class _Tp, class _Hash, class _Equal, class _Alloc>
 template <class _InputIterator>
 void
@@ -2101,17 +2063,10 @@ __hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_insert_multi(
 
 
 
-#ifndef _LIBCPP_CXX03_LANG
 template <class _Tp, class _Hash, class _Equal, class _Alloc>
 template <class _Key, class ..._Args>
 pair<typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator, bool>
 __hash_table<_Tp, _Hash, _Equal, _Alloc>::__emplace_unique_key_args(_Key const& __k, _Args&&... __args)
-#else
-template <class _Tp, class _Hash, class _Equal, class _Alloc>
-template <class _Key, class _Args>
-pair<typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator, bool>
-__hash_table<_Tp, _Hash, _Equal, _Alloc>::__emplace_unique_key_args(_Key const& __k, _Args& __args)
-#endif
 {
 
     size_t __hash = hash_function()(__k);
@@ -2135,11 +2090,7 @@ __hash_table<_Tp, _Hash, _Equal, _Alloc>::__emplace_unique_key_args(_Key const&
         }
     }
     {
-#ifndef _LIBCPP_CXX03_LANG
         __node_holder __h = __construct_node_hash(__hash, _VSTD::forward<_Args>(__args)...);
-#else
-        __node_holder __h = __construct_node_hash(__hash, __args);
-#endif
         if (size()+1 > __bc * max_load_factor() || __bc == 0)
         {
             rehash(_VSTD::max<size_type>(2 * __bc + !__is_hash_power2(__bc),
@@ -2178,8 +2129,6 @@ __done:
 #endif
 }
 
-#ifndef _LIBCPP_CXX03_LANG
-
 template <class _Tp, class _Hash, class _Equal, class _Alloc>
 template <class... _Args>
 pair<typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator, bool>
@@ -2220,36 +2169,6 @@ __hash_table<_Tp, _Hash, _Equal, _Alloc>::__emplace_hint_multi(
     return __r;
 }
 
-#else // _LIBCPP_CXX03_LANG
-
-template <class _Tp, class _Hash, class _Equal, class _Alloc>
-typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
-__hash_table<_Tp, _Hash, _Equal, _Alloc>::__insert_multi(const __container_value_type& __x)
-{
-    __node_holder __h = __construct_node(__x);
-    iterator __r = __node_insert_multi(__h.get());
-    __h.release();
-    return __r;
-}
-
-template <class _Tp, class _Hash, class _Equal, class _Alloc>
-typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
-__hash_table<_Tp, _Hash, _Equal, _Alloc>::__insert_multi(const_iterator __p,
-                                                         const __container_value_type& __x)
-{
-#if _LIBCPP_DEBUG_LEVEL == 2
-    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__p) == this,
-        "unordered container::insert(const_iterator, lvalue) called with an iterator not"
-        " referring to this unordered container");
-#endif
-    __node_holder __h = __construct_node(__x);
-    iterator __r = __node_insert_multi(__p, __h.get());
-    __h.release();
-    return __r;
-}
-
-#endif  // _LIBCPP_CXX03_LANG
-
 #if _LIBCPP_STD_VER > 14
 template <class _Tp, class _Hash, class _Equal, class _Alloc>
 template <class _NodeHandle, class _InsertReturnType>
@@ -2525,8 +2444,6 @@ __hash_table<_Tp, _Hash, _Equal, _Alloc>::find(const _Key& __k) const
     return end();
 }
 
-#ifndef _LIBCPP_CXX03_LANG
-
 template <class _Tp, class _Hash, class _Equal, class _Alloc>
 template <class ..._Args>
 typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_holder
@@ -2562,37 +2479,6 @@ __hash_table<_Tp, _Hash, _Equal, _Alloc>::__construct_node_hash(
     return __h;
 }
 
-#else  // _LIBCPP_CXX03_LANG
-
-template <class _Tp, class _Hash, class _Equal, class _Alloc>
-typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_holder
-__hash_table<_Tp, _Hash, _Equal, _Alloc>::__construct_node(const __container_value_type& __v)
-{
-    __node_allocator& __na = __node_alloc();
-    __node_holder __h(__node_traits::allocate(__na, 1), _Dp(__na));
-    __node_traits::construct(__na, _NodeTypes::__get_ptr(__h->__value_), __v);
-    __h.get_deleter().__value_constructed = true;
-    __h->__hash_ = hash_function()(__h->__value_);
-    __h->__next_ = nullptr;
-    return __h;
-}
-
-template <class _Tp, class _Hash, class _Equal, class _Alloc>
-typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_holder
-__hash_table<_Tp, _Hash, _Equal, _Alloc>::__construct_node_hash(size_t __hash,
-                                                                const __container_value_type& __v)
-{
-    __node_allocator& __na = __node_alloc();
-    __node_holder __h(__node_traits::allocate(__na, 1), _Dp(__na));
-    __node_traits::construct(__na, _NodeTypes::__get_ptr(__h->__value_), __v);
-    __h.get_deleter().__value_constructed = true;
-    __h->__hash_ = __hash;
-    __h->__next_ = nullptr;
-    return __h;
-}
-
-#endif  // _LIBCPP_CXX03_LANG
-
 template <class _Tp, class _Hash, class _Equal, class _Alloc>
 typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
 __hash_table<_Tp, _Hash, _Equal, _Alloc>::erase(const_iterator __p)
diff --git a/libcxx/include/__mutex_base b/libcxx/include/__mutex_base
index 8b4b74802b194..c54a01994c6cc 100644
--- a/libcxx/include/__mutex_base
+++ b/libcxx/include/__mutex_base
@@ -146,7 +146,6 @@ private:
     unique_lock& operator=(unique_lock const&); // = delete;
 
 public:
-#ifndef _LIBCPP_CXX03_LANG
     _LIBCPP_INLINE_VISIBILITY
     unique_lock(unique_lock&& __u) _NOEXCEPT
         : __m_(__u.__m_), __owns_(__u.__owns_)
@@ -163,8 +162,6 @@ public:
             return *this;
         }
 
-#endif  // _LIBCPP_CXX03_LANG
-
     void lock();
     bool try_lock();
 
diff --git a/libcxx/include/__split_buffer b/libcxx/include/__split_buffer
index fce209f8287eb..d2128049efa04 100644
--- a/libcxx/include/__split_buffer
+++ b/libcxx/include/__split_buffer
@@ -68,7 +68,6 @@ public:
     __split_buffer(size_type __cap, size_type __start, __alloc_rr& __a);
     ~__split_buffer();
 
-#ifndef _LIBCPP_CXX03_LANG
     __split_buffer(__split_buffer&& __c)
         _NOEXCEPT_(is_nothrow_move_constructible<allocator_type>::value);
     __split_buffer(__split_buffer&& __c, const __alloc_rr& __a);
@@ -76,7 +75,6 @@ public:
         _NOEXCEPT_((__alloc_traits::propagate_on_container_move_assignment::value &&
                 is_nothrow_move_assignable<allocator_type>::value) ||
                !__alloc_traits::propagate_on_container_move_assignment::value);
-#endif  // _LIBCPP_CXX03_LANG
 
     _LIBCPP_INLINE_VISIBILITY       iterator begin() _NOEXCEPT       {return __begin_;}
     _LIBCPP_INLINE_VISIBILITY const_iterator begin() const _NOEXCEPT {return __begin_;}
@@ -101,12 +99,10 @@ public:
     void shrink_to_fit() _NOEXCEPT;
     void push_front(const_reference __x);
     _LIBCPP_INLINE_VISIBILITY void push_back(const_reference __x);
-#ifndef _LIBCPP_CXX03_LANG
     void push_front(value_type&& __x);
     void push_back(value_type&& __x);
     template <class... _Args>
         void emplace_back(_Args&&... __args);
-#endif  // !defined(_LIBCPP_CXX03_LANG)
 
     _LIBCPP_INLINE_VISIBILITY void pop_front() {__destruct_at_begin(__begin_+1);}
     _LIBCPP_INLINE_VISIBILITY void pop_back() {__destruct_at_end(__end_-1);}
@@ -350,8 +346,6 @@ __split_buffer<_Tp, _Allocator>::~__split_buffer()
         __alloc_traits::deallocate(__alloc(), __first_, capacity());
 }
 
-#ifndef _LIBCPP_CXX03_LANG
-
 template <class _Tp, class _Allocator>
 __split_buffer<_Tp, _Allocator>::__split_buffer(__split_buffer&& __c)
     _NOEXCEPT_(is_nothrow_move_constructible<allocator_type>::value)
@@ -412,8 +406,6 @@ __split_buffer<_Tp, _Allocator>::operator=(__split_buffer&& __c)
     return *this;
 }
 
-#endif  // _LIBCPP_CXX03_LANG
-
 template <class _Tp, class _Allocator>
 void
 __split_buffer<_Tp, _Allocator>::swap(__split_buffer& __x)
@@ -499,8 +491,6 @@ __split_buffer<_Tp, _Allocator>::push_front(const_reference __x)
     --__begin_;
 }
 
-#ifndef _LIBCPP_CXX03_LANG
-
 template <class _Tp, class _Allocator>
 void
 __split_buffer<_Tp, _Allocator>::push_front(value_type&& __x)
@@ -531,8 +521,6 @@ __split_buffer<_Tp, _Allocator>::push_front(value_type&& __x)
     --__begin_;
 }
 
-#endif  // _LIBCPP_CXX03_LANG
-
 template <class _Tp, class _Allocator>
 inline _LIBCPP_INLINE_VISIBILITY
 void
@@ -563,8 +551,6 @@ __split_buffer<_Tp, _Allocator>::push_back(const_reference __x)
     ++__end_;
 }
 
-#ifndef _LIBCPP_CXX03_LANG
-
 template <class _Tp, class _Allocator>
 void
 __split_buffer<_Tp, _Allocator>::push_back(value_type&& __x)
@@ -626,8 +612,6 @@ __split_buffer<_Tp, _Allocator>::emplace_back(_Args&&... __args)
     ++__end_;
 }
 
-#endif  // _LIBCPP_CXX03_LANG
-
 template <class _Tp, class _Allocator>
 inline _LIBCPP_INLINE_VISIBILITY
 void
diff --git a/libcxx/include/__tree b/libcxx/include/__tree
index 4c00ef83fad66..4e131a165f7ea 100644
--- a/libcxx/include/__tree
+++ b/libcxx/include/__tree
@@ -533,19 +533,17 @@ __tree_remove(_NodePtr __root, _NodePtr __z) _NOEXCEPT
 // node traits
 
 
-#ifndef _LIBCPP_CXX03_LANG
 template <class _Tp>
 struct __is_tree_value_type_imp : false_type {};
 
 template <class _Key, class _Value>
-struct __is_tree_value_type_imp<__value_type<_Key, _Value>> : true_type {};
+struct __is_tree_value_type_imp<__value_type<_Key, _Value> > : true_type {};
 
 template <class ..._Args>
 struct __is_tree_value_type : false_type {};
 
 template <class _One>
 struct __is_tree_value_type<_One> : __is_tree_value_type_imp<typename __uncvref<_One>::type> {};
-#endif
 
 template <class _Tp>
 struct __tree_key_value_types {
@@ -566,12 +564,10 @@ struct __tree_key_value_types {
   static __container_value_type* __get_ptr(__node_value_type& __n) {
     return _VSTD::addressof(__n);
   }
-#ifndef _LIBCPP_CXX03_LANG
   _LIBCPP_INLINE_VISIBILITY
   static __container_value_type&& __move(__node_value_type& __v) {
     return _VSTD::move(__v);
   }
-#endif
 };
 
 template <class _Key, class _Tp>
@@ -616,12 +612,10 @@ struct __tree_key_value_types<__value_type<_Key, _Tp> > {
     return _VSTD::addressof(__n.__get_value());
   }
 
-#ifndef _LIBCPP_CXX03_LANG
   _LIBCPP_INLINE_VISIBILITY
   static pair<key_type&&, mapped_type&&> __move(__node_value_type& __v) {
     return __v.__move();
   }
-#endif
 };
 
 template <class _VoidPtr>
@@ -1103,7 +1097,6 @@ public:
         void __assign_unique(_ForwardIterator __first, _ForwardIterator __last);
     template <class _InputIterator>
         void __assign_multi(_InputIterator __first, _InputIterator __last);
-#ifndef _LIBCPP_CXX03_LANG
     __tree(__tree&& __t)
         _NOEXCEPT_(
             is_nothrow_move_constructible<__node_allocator>::value &&
@@ -1114,8 +1107,6 @@ public:
             __node_traits::propagate_on_container_move_assignment::value &&
             is_nothrow_move_assignable<value_compare>::value &&
             is_nothrow_move_assignable<__node_allocator>::value);
-#endif // _LIBCPP_CXX03_LANG
-
     ~__tree();
 
     _LIBCPP_INLINE_VISIBILITY
@@ -1146,7 +1137,6 @@ public:
         _NOEXCEPT_(__is_nothrow_swappable<value_compare>::value);
 #endif
 
-#ifndef _LIBCPP_CXX03_LANG
     template <class _Key, class ..._Args>
     pair<iterator, bool>
     __emplace_unique_key_args(_Key const&, _Args&&... __args);
@@ -1255,15 +1245,6 @@ public:
       return __emplace_hint_unique_key_args(__p, __x.first, _VSTD::forward<_Pp>(__x)).first;
     }
 
-#else
-    template <class _Key, class _Args>
-    _LIBCPP_INLINE_VISIBILITY
-    pair<iterator, bool> __emplace_unique_key_args(_Key const&, _Args& __args);
-    template <class _Key, class _Args>
-    _LIBCPP_INLINE_VISIBILITY
-    pair<iterator, bool> __emplace_hint_unique_key_args(const_iterator, _Key const&, _Args&);
-#endif
-
     _LIBCPP_INLINE_VISIBILITY
     pair<iterator, bool> __insert_unique(const __container_value_type& __v) {
         return __emplace_unique_key_args(_NodeTypes::__get_key(__v), __v);
@@ -1274,12 +1255,6 @@ public:
         return __emplace_hint_unique_key_args(__p, _NodeTypes::__get_key(__v), __v).first;
     }
 
-#ifdef _LIBCPP_CXX03_LANG
-    _LIBCPP_INLINE_VISIBILITY
-    iterator __insert_multi(const __container_value_type& __v);
-    _LIBCPP_INLINE_VISIBILITY
-    iterator __insert_multi(const_iterator __p, const __container_value_type& __v);
-#else
     _LIBCPP_INLINE_VISIBILITY
     pair<iterator, bool> __insert_unique(__container_value_type&& __v) {
         return __emplace_unique_key_args(_NodeTypes::__get_key(__v), _VSTD::move(__v));
@@ -1332,8 +1307,6 @@ public:
         return __emplace_hint_multi(__p, _VSTD::forward<_Vp>(__v));
     }
 
-#endif // !_LIBCPP_CXX03_LANG
-
     _LIBCPP_INLINE_VISIBILITY
     pair<iterator, bool> __node_assign_unique(const __container_value_type& __v, __node_pointer __dest);
 
@@ -1471,12 +1444,8 @@ private:
                      __node_base_pointer& __dummy,
                      const _Key& __v);
 
-#ifndef _LIBCPP_CXX03_LANG
     template <class ..._Args>
     __node_holder __construct_node(_Args&& ...__args);
-#else
-    __node_holder __construct_node(const __container_value_type& __v);
-#endif
 
     void destroy(__node_pointer __nd) _NOEXCEPT;
 
@@ -1706,8 +1675,6 @@ __tree<_Tp, _Compare, _Allocator>::__tree(const __tree& __t)
     __begin_node() = __end_node();
 }
 
-#ifndef _LIBCPP_CXX03_LANG
-
 template <class _Tp, class _Compare, class _Allocator>
 __tree<_Tp, _Compare, _Allocator>::__tree(__tree&& __t)
     _NOEXCEPT_(
@@ -1814,8 +1781,6 @@ __tree<_Tp, _Compare, _Allocator>::operator=(__tree&& __t)
     return *this;
 }
 
-#endif  // _LIBCPP_CXX03_LANG
-
 template <class _Tp, class _Compare, class _Allocator>
 __tree<_Tp, _Compare, _Allocator>::~__tree()
 {
@@ -2117,17 +2082,10 @@ void __tree<_Tp, _Compare, _Allocator>::__insert_node_at(
     ++size();
 }
 
-#ifndef _LIBCPP_CXX03_LANG
 template <class _Tp, class _Compare, class _Allocator>
 template <class _Key, class... _Args>
 pair<typename __tree<_Tp, _Compare, _Allocator>::iterator, bool>
 __tree<_Tp, _Compare, _Allocator>::__emplace_unique_key_args(_Key const& __k, _Args&&... __args)
-#else
-template <class _Tp, class _Compare, class _Allocator>
-template <class _Key, class _Args>
-pair<typename __tree<_Tp, _Compare, _Allocator>::iterator, bool>
-__tree<_Tp, _Compare, _Allocator>::__emplace_unique_key_args(_Key const& __k, _Args& __args)
-#endif
 {
     __parent_pointer __parent;
     __node_base_pointer& __child = __find_equal(__parent, __k);
@@ -2135,11 +2093,7 @@ __tree<_Tp, _Compare, _Allocator>::__emplace_unique_key_args(_Key const& __k, _A
     bool __inserted = false;
     if (__child == nullptr)
     {
-#ifndef _LIBCPP_CXX03_LANG
         __node_holder __h = __construct_node(_VSTD::forward<_Args>(__args)...);
-#else
-        __node_holder __h = __construct_node(__args);
-#endif
         __insert_node_at(__parent, __child, static_cast<__node_base_pointer>(__h.get()));
         __r = __h.release();
         __inserted = true;
@@ -2147,19 +2101,11 @@ __tree<_Tp, _Compare, _Allocator>::__emplace_unique_key_args(_Key const& __k, _A
     return pair<iterator, bool>(iterator(__r), __inserted);
 }
 
-#ifndef _LIBCPP_CXX03_LANG
 template <class _Tp, class _Compare, class _Allocator>
 template <class _Key, class... _Args>
 pair<typename __tree<_Tp, _Compare, _Allocator>::iterator, bool>
 __tree<_Tp, _Compare, _Allocator>::__emplace_hint_unique_key_args(
     const_iterator __p, _Key const& __k, _Args&&... __args)
-#else
-template <class _Tp, class _Compare, class _Allocator>
-template <class _Key, class _Args>
-pair<typename __tree<_Tp, _Compare, _Allocator>::iterator, bool>
-__tree<_Tp, _Compare, _Allocator>::__emplace_hint_unique_key_args(
-    const_iterator __p, _Key const& __k, _Args& __args)
-#endif
 {
     __parent_pointer __parent;
     __node_base_pointer __dummy;
@@ -2168,11 +2114,7 @@ __tree<_Tp, _Compare, _Allocator>::__emplace_hint_unique_key_args(
     bool __inserted = false;
     if (__child == nullptr)
     {
-#ifndef _LIBCPP_CXX03_LANG
         __node_holder __h = __construct_node(_VSTD::forward<_Args>(__args)...);
-#else
-        __node_holder __h = __construct_node(__args);
-#endif
         __insert_node_at(__parent, __child, static_cast<__node_base_pointer>(__h.get()));
         __r = __h.release();
         __inserted = true;
@@ -2180,8 +2122,6 @@ __tree<_Tp, _Compare, _Allocator>::__emplace_hint_unique_key_args(
     return pair<iterator, bool>(iterator(__r), __inserted);
 }
 
-#ifndef _LIBCPP_CXX03_LANG
-
 template <class _Tp, class _Compare, class _Allocator>
 template <class ..._Args>
 typename __tree<_Tp, _Compare, _Allocator>::__node_holder
@@ -2259,46 +2199,6 @@ __tree<_Tp, _Compare, _Allocator>::__emplace_hint_multi(const_iterator __p,
     return iterator(static_cast<__node_pointer>(__h.release()));
 }
 
-
-#else  // _LIBCPP_CXX03_LANG
-
-template <class _Tp, class _Compare, class _Allocator>
-typename __tree<_Tp, _Compare, _Allocator>::__node_holder
-__tree<_Tp, _Compare, _Allocator>::__construct_node(const __container_value_type& __v)
-{
-    __node_allocator& __na = __node_alloc();
-    __node_holder __h(__node_traits::allocate(__na, 1), _Dp(__na));
-    __node_traits::construct(__na, _NodeTypes::__get_ptr(__h->__value_), __v);
-    __h.get_deleter().__value_constructed = true;
-    return __h;
-}
-
-#endif  // _LIBCPP_CXX03_LANG
-
-#ifdef _LIBCPP_CXX03_LANG
-template <class _Tp, class _Compare, class _Allocator>
-typename __tree<_Tp, _Compare, _Allocator>::iterator
-__tree<_Tp, _Compare, _Allocator>::__insert_multi(const __container_value_type& __v)
-{
-    __parent_pointer __parent;
-    __node_base_pointer& __child = __find_leaf_high(__parent, _NodeTypes::__get_key(__v));
-    __node_holder __h = __construct_node(__v);
-    __insert_node_at(__parent, __child, static_cast<__node_base_pointer>(__h.get()));
-    return iterator(__h.release());
-}
-
-template <class _Tp, class _Compare, class _Allocator>
-typename __tree<_Tp, _Compare, _Allocator>::iterator
-__tree<_Tp, _Compare, _Allocator>::__insert_multi(const_iterator __p, const __container_value_type& __v)
-{
-    __parent_pointer __parent;
-    __node_base_pointer& __child = __find_leaf(__p, __parent, _NodeTypes::__get_key(__v));
-    __node_holder __h = __construct_node(__v);
-    __insert_node_at(__parent, __child, static_cast<__node_base_pointer>(__h.get()));
-    return iterator(__h.release());
-}
-#endif
-
 template <class _Tp, class _Compare, class _Allocator>
 pair<typename __tree<_Tp, _Compare, _Allocator>::iterator, bool>
 __tree<_Tp, _Compare, _Allocator>::__node_assign_unique(const __container_value_type& __v, __node_pointer __nd)
diff --git a/libcxx/include/array b/libcxx/include/array
index e73bbe7fea5f7..da2ae2e0c414d 100644
--- a/libcxx/include/array
+++ b/libcxx/include/array
@@ -459,8 +459,6 @@ get(const array<_Tp, _Size>& __a) _NOEXCEPT
     return __a.__elems_[_Ip];
 }
 
-#ifndef _LIBCPP_CXX03_LANG
-
 template <size_t _Ip, class _Tp, size_t _Size>
 inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
 _Tp&&
@@ -479,8 +477,6 @@ get(const array<_Tp, _Size>&& __a) _NOEXCEPT
     return _VSTD::move(__a.__elems_[_Ip]);
 }
 
-#endif  // !_LIBCPP_CXX03_LANG
-
 #if _LIBCPP_STD_VER > 17
 
 template <typename _Tp, size_t _Size, size_t... _Index>
diff --git a/libcxx/include/sstream b/libcxx/include/sstream
index 14c91971c2f1b..4b1d17cfde332 100644
--- a/libcxx/include/sstream
+++ b/libcxx/include/sstream
@@ -213,12 +213,10 @@ public:
     inline _LIBCPP_INLINE_VISIBILITY
     explicit basic_stringbuf(const string_type& __s,
                              ios_base::openmode __wch = ios_base::in | ios_base::out);
-#ifndef _LIBCPP_CXX03_LANG
     basic_stringbuf(basic_stringbuf&& __rhs);
 
     // 27.8.1.2 Assign and swap:
     basic_stringbuf& operator=(basic_stringbuf&& __rhs);
-#endif
     void swap(basic_stringbuf& __rhs);
 
     // 27.8.1.3 Get and set:
@@ -254,8 +252,6 @@ basic_stringbuf<_CharT, _Traits, _Allocator>::basic_stringbuf(const string_type&
     str(__s);
 }
 
-#ifndef _LIBCPP_CXX03_LANG
-
 template <class _CharT, class _Traits, class _Allocator>
 basic_stringbuf<_CharT, _Traits, _Allocator>::basic_stringbuf(basic_stringbuf&& __rhs)
     : __mode_(__rhs.__mode_)
@@ -345,8 +341,6 @@ basic_stringbuf<_CharT, _Traits, _Allocator>::operator=(basic_stringbuf&& __rhs)
     return *this;
 }
 
-#endif  // _LIBCPP_CXX03_LANG
-
 template <class _CharT, class _Traits, class _Allocator>
 void
 basic_stringbuf<_CharT, _Traits, _Allocator>::swap(basic_stringbuf& __rhs)
@@ -649,13 +643,11 @@ public:
     inline _LIBCPP_INLINE_VISIBILITY
     explicit basic_istringstream(const string_type& __s,
                                  ios_base::openmode __wch = ios_base::in);
-#ifndef _LIBCPP_CXX03_LANG
     inline _LIBCPP_INLINE_VISIBILITY
     basic_istringstream(basic_istringstream&& __rhs);
 
     // 27.8.2.2 Assign and swap:
     basic_istringstream& operator=(basic_istringstream&& __rhs);
-#endif  // _LIBCPP_CXX03_LANG
     inline _LIBCPP_INLINE_VISIBILITY
     void swap(basic_istringstream& __rhs);
 
@@ -683,8 +675,6 @@ basic_istringstream<_CharT, _Traits, _Allocator>::basic_istringstream(const stri
 {
 }
 
-#ifndef _LIBCPP_CXX03_LANG
-
 template <class _CharT, class _Traits, class _Allocator>
 basic_istringstream<_CharT, _Traits, _Allocator>::basic_istringstream(basic_istringstream&& __rhs)
     : basic_istream<_CharT, _Traits>(_VSTD::move(__rhs)),
@@ -702,8 +692,6 @@ basic_istringstream<_CharT, _Traits, _Allocator>::operator=(basic_istringstream&
     return *this;
 }
 
-#endif  // _LIBCPP_CXX03_LANG
-
 template <class _CharT, class _Traits, class _Allocator>
 void basic_istringstream<_CharT, _Traits, _Allocator>::swap(basic_istringstream& __rhs)
 {
@@ -766,13 +754,11 @@ public:
     inline _LIBCPP_INLINE_VISIBILITY
     explicit basic_ostringstream(const string_type& __s,
                                  ios_base::openmode __wch = ios_base::out);
-#ifndef _LIBCPP_CXX03_LANG
     inline _LIBCPP_INLINE_VISIBILITY
     basic_ostringstream(basic_ostringstream&& __rhs);
 
     // 27.8.2.2 Assign and swap:
     basic_ostringstream& operator=(basic_ostringstream&& __rhs);
-#endif  // _LIBCPP_CXX03_LANG
     inline _LIBCPP_INLINE_VISIBILITY
     void swap(basic_ostringstream& __rhs);
 
@@ -800,8 +786,6 @@ basic_ostringstream<_CharT, _Traits, _Allocator>::basic_ostringstream(const stri
 {
 }
 
-#ifndef _LIBCPP_CXX03_LANG
-
 template <class _CharT, class _Traits, class _Allocator>
 basic_ostringstream<_CharT, _Traits, _Allocator>::basic_ostringstream(basic_ostringstream&& __rhs)
     : basic_ostream<_CharT, _Traits>(_VSTD::move(__rhs)),
@@ -819,8 +803,6 @@ basic_ostringstream<_CharT, _Traits, _Allocator>::operator=(basic_ostringstream&
     return *this;
 }
 
-#endif  // _LIBCPP_CXX03_LANG
-
 template <class _CharT, class _Traits, class _Allocator>
 void
 basic_ostringstream<_CharT, _Traits, _Allocator>::swap(basic_ostringstream& __rhs)
@@ -885,13 +867,11 @@ public:
     inline _LIBCPP_INLINE_VISIBILITY
     explicit basic_stringstream(const string_type& __s,
                                 ios_base::openmode __wch = ios_base::in | ios_base::out);
-#ifndef _LIBCPP_CXX03_LANG
     inline _LIBCPP_INLINE_VISIBILITY
     basic_stringstream(basic_stringstream&& __rhs);
 
     // 27.8.2.2 Assign and swap:
     basic_stringstream& operator=(basic_stringstream&& __rhs);
-#endif  // _LIBCPP_CXX03_LANG
     inline _LIBCPP_INLINE_VISIBILITY
     void swap(basic_stringstream& __rhs);
 
@@ -919,8 +899,6 @@ basic_stringstream<_CharT, _Traits, _Allocator>::basic_stringstream(const string
 {
 }
 
-#ifndef _LIBCPP_CXX03_LANG
-
 template <class _CharT, class _Traits, class _Allocator>
 basic_stringstream<_CharT, _Traits, _Allocator>::basic_stringstream(basic_stringstream&& __rhs)
     : basic_iostream<_CharT, _Traits>(_VSTD::move(__rhs)),
@@ -938,8 +916,6 @@ basic_stringstream<_CharT, _Traits, _Allocator>::operator=(basic_stringstream&&
     return *this;
 }
 
-#endif  // _LIBCPP_CXX03_LANG
-
 template <class _CharT, class _Traits, class _Allocator>
 void
 basic_stringstream<_CharT, _Traits, _Allocator>::swap(basic_stringstream& __rhs)
diff --git a/libcxx/include/type_traits b/libcxx/include/type_traits
index 75d60cddd305c..733b7eb2a6f29 100644
--- a/libcxx/include/type_traits
+++ b/libcxx/include/type_traits
@@ -4273,7 +4273,6 @@ _LIBCPP_INLINE_VAR constexpr bool negation_v
 #endif  // _LIBCPP_STD_VER > 14
 
 // These traits are used in __tree and __hash_table
-#ifndef _LIBCPP_CXX03_LANG
 struct __extract_key_fail_tag {};
 struct __extract_key_self_tag {};
 struct __extract_key_first_tag {};
@@ -4285,7 +4284,7 @@ struct __can_extract_key
                   __extract_key_fail_tag>::type {};
 
 template <class _Pair, class _Key, class _First, class _Second>
-struct __can_extract_key<_Pair, _Key, pair<_First, _Second>>
+struct __can_extract_key<_Pair, _Key, pair<_First, _Second> >
     : conditional<_IsSame<typename remove_const<_First>::type, _Key>::value,
                   __extract_key_first_tag, __extract_key_fail_tag>::type {};
 
@@ -4303,8 +4302,6 @@ template <class _ValTy, class _Key, class _RawValTy>
 struct __can_extract_map_key<_ValTy, _Key, _Key, _RawValTy>
     : false_type {};
 
-#endif
-
 #ifndef _LIBCPP_HAS_NO_BUILTIN_IS_CONSTANT_EVALUATED
 #if _LIBCPP_STD_VER > 17
 _LIBCPP_INLINE_VISIBILITY