diff --git a/libcxx/include/__split_buffer b/libcxx/include/__split_buffer
--- a/libcxx/include/__split_buffer
+++ b/libcxx/include/__split_buffer
@@ -44,139 +44,165 @@
 template <class _Tp, class _Allocator = allocator<_Tp> >
 struct __split_buffer
 {
-private:
-    __split_buffer(const __split_buffer&);
-    __split_buffer& operator=(const __split_buffer&);
 public:
-    typedef _Tp                                             value_type;
-    typedef _Allocator                                      allocator_type;
-    typedef __libcpp_remove_reference_t<allocator_type>     __alloc_rr;
-    typedef allocator_traits<__alloc_rr>                    __alloc_traits;
-    typedef value_type&                                     reference;
-    typedef const value_type&                               const_reference;
-    typedef typename __alloc_traits::size_type              size_type;
-    typedef typename __alloc_traits::difference_type        difference_type;
-    typedef typename __alloc_traits::pointer                pointer;
-    typedef typename __alloc_traits::const_pointer          const_pointer;
-    typedef pointer                                         iterator;
-    typedef const_pointer                                   const_iterator;
-
-    pointer                                         __first_;
-    pointer                                         __begin_;
-    pointer                                         __end_;
-    __compressed_pair<pointer, allocator_type> __end_cap_;
-
-    typedef __add_lvalue_reference_t<allocator_type> __alloc_ref;
-    typedef __add_lvalue_reference_t<allocator_type> __alloc_const_ref;
-
-    _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI __alloc_rr&           __alloc() _NOEXCEPT         {return __end_cap_.second();}
-    _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI const __alloc_rr&     __alloc() const _NOEXCEPT   {return __end_cap_.second();}
-    _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI pointer&              __end_cap() _NOEXCEPT       {return __end_cap_.first();}
-    _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI const pointer&        __end_cap() const _NOEXCEPT {return __end_cap_.first();}
-
-    _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI
-    __split_buffer()
-        _NOEXCEPT_(is_nothrow_default_constructible<allocator_type>::value);
-    _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI
-    explicit __split_buffer(__alloc_rr& __a);
-    _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI
-    explicit __split_buffer(const __alloc_rr& __a);
-    _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI __split_buffer(size_type __cap, size_type __start, __alloc_rr& __a);
-    _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI ~__split_buffer();
-
-    _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI __split_buffer(__split_buffer&& __c)
-        _NOEXCEPT_(is_nothrow_move_constructible<allocator_type>::value);
-    _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI __split_buffer(__split_buffer&& __c, const __alloc_rr& __a);
-    _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI __split_buffer& operator=(__split_buffer&& __c)
-        _NOEXCEPT_((__alloc_traits::propagate_on_container_move_assignment::value &&
-                is_nothrow_move_assignable<allocator_type>::value) ||
-               !__alloc_traits::propagate_on_container_move_assignment::value);
-
-    _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI       iterator begin() _NOEXCEPT       {return __begin_;}
-    _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI const_iterator begin() const _NOEXCEPT {return __begin_;}
-    _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI       iterator end() _NOEXCEPT         {return __end_;}
-    _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI const_iterator end() const _NOEXCEPT   {return __end_;}
-
-    _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI
-    void clear() _NOEXCEPT
-        {__destruct_at_end(__begin_);}
-    _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI size_type size() const {return static_cast<size_type>(__end_ - __begin_);}
-    _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI bool empty()     const {return __end_ == __begin_;}
-    _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI size_type capacity() const {return static_cast<size_type>(__end_cap() - __first_);}
-    _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI size_type __front_spare() const {return static_cast<size_type>(__begin_ - __first_);}
-    _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI size_type __back_spare() const {return static_cast<size_type>(__end_cap() - __end_);}
-
-    _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI       reference front()       {return *__begin_;}
-    _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI const_reference front() const {return *__begin_;}
-    _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI       reference back()        {return *(__end_ - 1);}
-    _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI const_reference back() const  {return *(__end_ - 1);}
-
-    _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void reserve(size_type __n);
-    _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void shrink_to_fit() _NOEXCEPT;
-    _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void push_front(const_reference __x);
-    _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void push_back(const_reference __x);
-    _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void push_front(value_type&& __x);
-    _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void push_back(value_type&& __x);
-    template <class... _Args>
-        _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void emplace_back(_Args&&... __args);
-
-    _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void pop_front() {__destruct_at_begin(__begin_+1);}
-    _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void pop_back() {__destruct_at_end(__end_-1);}
-
-    _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void __construct_at_end(size_type __n);
-    _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void __construct_at_end(size_type __n, const_reference __x);
-    template <class _InputIter>
-    _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI __enable_if_t<__is_exactly_cpp17_input_iterator<_InputIter>::value>
-        __construct_at_end(_InputIter __first, _InputIter __last);
-    template <class _ForwardIterator>
-    _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI __enable_if_t<__is_cpp17_forward_iterator<_ForwardIterator>::value>
-        __construct_at_end(_ForwardIterator __first, _ForwardIterator __last);
-
-    _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void __destruct_at_begin(pointer __new_begin)
-        {__destruct_at_begin(__new_begin, is_trivially_destructible<value_type>());}
-        _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI
-        void __destruct_at_begin(pointer __new_begin, false_type);
-        _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI
-        void __destruct_at_begin(pointer __new_begin, true_type);
-
-    _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI
-    void __destruct_at_end(pointer __new_last) _NOEXCEPT
-        {__destruct_at_end(__new_last, false_type());}
-    _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI
-        void __destruct_at_end(pointer __new_last, false_type) _NOEXCEPT;
-    _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI
-        void __destruct_at_end(pointer __new_last, true_type) _NOEXCEPT;
-
-    _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void swap(__split_buffer& __x)
-        _NOEXCEPT_(!__alloc_traits::propagate_on_container_swap::value||
-                   __is_nothrow_swappable<__alloc_rr>::value);
+  using value_type      = _Tp;
+  using allocator_type  = _Allocator;
+  using __alloc_rr      = __libcpp_remove_reference_t<allocator_type>;
+  using __alloc_traits  = allocator_traits<__alloc_rr>;
+  using reference       = value_type&;
+  using const_reference = const value_type&;
+  using size_type       = typename __alloc_traits::size_type;
+  using difference_type = typename __alloc_traits::difference_type;
+  using pointer         = typename __alloc_traits::pointer;
+  using const_pointer   = typename __alloc_traits::const_pointer;
+  using iterator        = pointer;
+  using const_iterator  = const_pointer;
+
+  pointer __first_;
+  pointer __begin_;
+  pointer __end_;
+  __compressed_pair<pointer, allocator_type> __end_cap_;
+
+  using __alloc_ref       = __add_lvalue_reference_t<allocator_type>;
+  using __alloc_const_ref = __add_lvalue_reference_t<allocator_type>;
+
+  __split_buffer(const __split_buffer&) = delete;
+  __split_buffer& operator=(const __split_buffer&) = delete;
+
+  _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI __split_buffer()
+      _NOEXCEPT_(is_nothrow_default_constructible<allocator_type>::value)
+      : __first_(nullptr), __begin_(nullptr), __end_(nullptr), __end_cap_(nullptr, __default_init_tag()) {}
+
+  _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI explicit __split_buffer(__alloc_rr& __a)
+      : __first_(nullptr), __begin_(nullptr), __end_(nullptr), __end_cap_(nullptr, __a) {}
+
+  _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI explicit __split_buffer(const __alloc_rr& __a)
+      : __first_(nullptr), __begin_(nullptr), __end_(nullptr), __end_cap_(nullptr, __a) {}
+
+  _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI
+  __split_buffer(size_type __cap, size_type __start, __alloc_rr& __a);
+
+  _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI __split_buffer(__split_buffer&& __c)
+      _NOEXCEPT_(is_nothrow_move_constructible<allocator_type>::value);
+
+  _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI __split_buffer(__split_buffer&& __c, const __alloc_rr& __a);
+
+  _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI __split_buffer& operator=(__split_buffer&& __c)
+      _NOEXCEPT_((__alloc_traits::propagate_on_container_move_assignment::value &&
+                  is_nothrow_move_assignable<allocator_type>::value) ||
+                 !__alloc_traits::propagate_on_container_move_assignment::value);
+
+  _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI ~__split_buffer();
+
+  _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI __alloc_rr& __alloc() _NOEXCEPT { return __end_cap_.second(); }
+  _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI const __alloc_rr& __alloc() const _NOEXCEPT {
+    return __end_cap_.second();
+  }
+
+  _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI pointer& __end_cap() _NOEXCEPT { return __end_cap_.first(); }
+  _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI const pointer& __end_cap() const _NOEXCEPT {
+    return __end_cap_.first();
+  }
+
+  _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI iterator begin() _NOEXCEPT { return __begin_; }
+  _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI const_iterator begin() const _NOEXCEPT { return __begin_; }
+
+  _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI iterator end() _NOEXCEPT { return __end_; }
+  _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI const_iterator end() const _NOEXCEPT { return __end_; }
+
+  _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void clear() _NOEXCEPT { __destruct_at_end(__begin_); }
+
+  _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI size_type size() const {
+    return static_cast<size_type>(__end_ - __begin_);
+  }
+
+  _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI bool empty() const { return __end_ == __begin_; }
+
+  _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI size_type capacity() const {
+    return static_cast<size_type>(__end_cap() - __first_);
+  }
+
+  _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI size_type __front_spare() const {
+    return static_cast<size_type>(__begin_ - __first_);
+  }
+
+  _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI size_type __back_spare() const {
+    return static_cast<size_type>(__end_cap() - __end_);
+  }
+
+  _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI reference front() { return *__begin_; }
+  _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI const_reference front() const { return *__begin_; }
+  _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI reference back() { return *(__end_ - 1); }
+  _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI const_reference back() const { return *(__end_ - 1); }
+
+  _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void reserve(size_type __n);
+  _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void shrink_to_fit() _NOEXCEPT;
+  _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void push_front(const_reference __x);
+  _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void push_back(const_reference __x);
+  _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void push_front(value_type&& __x);
+  _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void push_back(value_type&& __x);
+
+  template <class... _Args>
+  _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void emplace_back(_Args&&... __args);
+
+  _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void pop_front() { __destruct_at_begin(__begin_ + 1); }
+  _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void pop_back() { __destruct_at_end(__end_ - 1); }
+
+  _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void __construct_at_end(size_type __n);
+  _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void __construct_at_end(size_type __n, const_reference __x);
+
+  template <class _InputIter>
+  _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI
+      __enable_if_t<__is_exactly_cpp17_input_iterator<_InputIter>::value>
+      __construct_at_end(_InputIter __first, _InputIter __last);
 
-    _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI bool __invariants() const;
+  template <class _ForwardIterator>
+  _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI
+      __enable_if_t<__is_cpp17_forward_iterator<_ForwardIterator>::value>
+      __construct_at_end(_ForwardIterator __first, _ForwardIterator __last);
+
+  _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void __destruct_at_begin(pointer __new_begin) {
+    __destruct_at_begin(__new_begin, is_trivially_destructible<value_type>());
+  }
+
+  _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void __destruct_at_begin(pointer __new_begin, false_type);
+  _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void __destruct_at_begin(pointer __new_begin, true_type);
+
+  _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void __destruct_at_end(pointer __new_last) _NOEXCEPT {
+    __destruct_at_end(__new_last, false_type());
+  }
+
+  _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void __destruct_at_end(pointer __new_last, false_type) _NOEXCEPT;
+  _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void __destruct_at_end(pointer __new_last, true_type) _NOEXCEPT;
+
+  _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void swap(__split_buffer& __x)
+      _NOEXCEPT_(!__alloc_traits::propagate_on_container_swap::value || __is_nothrow_swappable<__alloc_rr>::value);
+
+  _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI bool __invariants() const;
 
 private:
-    _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI
-    void __move_assign_alloc(__split_buffer& __c, true_type)
-        _NOEXCEPT_(is_nothrow_move_assignable<allocator_type>::value)
-        {
-            __alloc() = _VSTD::move(__c.__alloc());
-        }
+  _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void __move_assign_alloc(__split_buffer& __c, true_type)
+      _NOEXCEPT_(is_nothrow_move_assignable<allocator_type>::value) {
+    __alloc() = _VSTD::move(__c.__alloc());
+  }
 
-    _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI
-    void __move_assign_alloc(__split_buffer&, false_type) _NOEXCEPT
-        {}
-
-    struct _ConstructTransaction {
-      _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI explicit _ConstructTransaction(pointer* __p, size_type __n) _NOEXCEPT
-      : __pos_(*__p), __end_(*__p + __n), __dest_(__p) {
-      }
-      _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI ~_ConstructTransaction() {
-        *__dest_ = __pos_;
-      }
-      pointer __pos_;
-     const pointer __end_;
-    private:
-     pointer *__dest_;
-    };
+  _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void __move_assign_alloc(__split_buffer&, false_type) _NOEXCEPT {}
+
+  struct _ConstructTransaction {
+    _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI explicit _ConstructTransaction(
+        pointer* __p, size_type __n) _NOEXCEPT
+        : __pos_(*__p),
+          __end_(*__p + __n),
+          __dest_(__p) {}
+
+    _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI ~_ConstructTransaction() { *__dest_ = __pos_; }
+
+    pointer __pos_;
+    const pointer __end_;
+
+  private:
+    pointer* __dest_;
+  };
 };
 
 template <class _Tp, class _Allocator>
@@ -328,31 +354,6 @@
     __end_cap() = __first_ + __cap;
 }
 
-template <class _Tp, class _Allocator>
-_LIBCPP_CONSTEXPR_SINCE_CXX20
-inline
-__split_buffer<_Tp, _Allocator>::__split_buffer()
-    _NOEXCEPT_(is_nothrow_default_constructible<allocator_type>::value)
-    : __first_(nullptr), __begin_(nullptr), __end_(nullptr), __end_cap_(nullptr, __default_init_tag())
-{
-}
-
-template <class _Tp, class _Allocator>
-_LIBCPP_CONSTEXPR_SINCE_CXX20
-inline
-__split_buffer<_Tp, _Allocator>::__split_buffer(__alloc_rr& __a)
-    : __first_(nullptr), __begin_(nullptr), __end_(nullptr), __end_cap_(nullptr, __a)
-{
-}
-
-template <class _Tp, class _Allocator>
-_LIBCPP_CONSTEXPR_SINCE_CXX20
-inline
-__split_buffer<_Tp, _Allocator>::__split_buffer(const __alloc_rr& __a)
-    : __first_(nullptr), __begin_(nullptr), __end_(nullptr), __end_cap_(nullptr, __a)
-{
-}
-
 template <class _Tp, class _Allocator>
 _LIBCPP_CONSTEXPR_SINCE_CXX20
 __split_buffer<_Tp, _Allocator>::~__split_buffer()