Add libc++ and libc++abi to third-party.

third_party/libcxx/include/forward_list

Index: third_party/libcxx/include/forward_list
===================================================================
--- third_party/libcxx/include/forward_list	(revision 0)
+++ third_party/libcxx/include/forward_list	(revision 0)
@@ -0,0 +1,1663 @@
+// -*- C++ -*-
+//===----------------------- forward_list ---------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_FORWARD_LIST
+#define _LIBCPP_FORWARD_LIST
+
+/*
+    forward_list synopsis
+
+namespace std
+{
+
+template <class T, class Allocator = allocator<T>>
+class forward_list
+{
+public:
+    typedef T         value_type;
+    typedef Allocator allocator_type;
+
+    typedef value_type&                                                reference;
+    typedef const value_type&                                          const_reference;
+    typedef typename allocator_traits<allocator_type>::pointer         pointer;
+    typedef typename allocator_traits<allocator_type>::const_pointer   const_pointer;
+    typedef typename allocator_traits<allocator_type>::size_type       size_type;
+    typedef typename allocator_traits<allocator_type>::difference_type difference_type;
+
+    typedef <details> iterator;
+    typedef <details> const_iterator;
+
+    forward_list()
+        noexcept(is_nothrow_default_constructible<allocator_type>::value);
+    explicit forward_list(const allocator_type& a);
+    explicit forward_list(size_type n);
+    explicit forward_list(size_type n, const allocator_type& a); // C++14
+    forward_list(size_type n, const value_type& v);
+    forward_list(size_type n, const value_type& v, const allocator_type& a);
+    template <class InputIterator>
+        forward_list(InputIterator first, InputIterator last);
+    template <class InputIterator>
+        forward_list(InputIterator first, InputIterator last, const allocator_type& a);
+    forward_list(const forward_list& x);
+    forward_list(const forward_list& x, const allocator_type& a);
+    forward_list(forward_list&& x)
+        noexcept(is_nothrow_move_constructible<allocator_type>::value);
+    forward_list(forward_list&& x, const allocator_type& a);
+    forward_list(initializer_list<value_type> il);
+    forward_list(initializer_list<value_type> il, const allocator_type& a);
+
+    ~forward_list();
+
+    forward_list& operator=(const forward_list& x);
+    forward_list& operator=(forward_list&& x)
+        noexcept(
+             allocator_type::propagate_on_container_move_assignment::value &&
+             is_nothrow_move_assignable<allocator_type>::value);
+    forward_list& operator=(initializer_list<value_type> il);
+
+    template <class InputIterator>
+        void assign(InputIterator first, InputIterator last);
+    void assign(size_type n, const value_type& v);
+    void assign(initializer_list<value_type> il);
+
+    allocator_type get_allocator() const noexcept;
+
+    iterator       begin() noexcept;
+    const_iterator begin() const noexcept;
+    iterator       end() noexcept;
+    const_iterator end() const noexcept;
+
+    const_iterator cbegin() const noexcept;
+    const_iterator cend() const noexcept;
+
+    iterator       before_begin() noexcept;
+    const_iterator before_begin() const noexcept;
+    const_iterator cbefore_begin() const noexcept;
+
+    bool empty() const noexcept;
+    size_type max_size() const noexcept;
+
+    reference       front();
+    const_reference front() const;
+
+    template <class... Args> void emplace_front(Args&&... args);
+    void push_front(const value_type& v);
+    void push_front(value_type&& v);
+
+    void pop_front();
+
+    template <class... Args>
+        iterator emplace_after(const_iterator p, Args&&... args);
+    iterator insert_after(const_iterator p, const value_type& v);
+    iterator insert_after(const_iterator p, value_type&& v);
+    iterator insert_after(const_iterator p, size_type n, const value_type& v);
+    template <class InputIterator>
+        iterator insert_after(const_iterator p,
+                              InputIterator first, InputIterator last);
+    iterator insert_after(const_iterator p, initializer_list<value_type> il);
+
+    iterator erase_after(const_iterator p);
+    iterator erase_after(const_iterator first, const_iterator last);
+
+    void swap(forward_list& x)
+        noexcept(!allocator_type::propagate_on_container_swap::value ||
+                 __is_nothrow_swappable<allocator_type>::value);
+
+    void resize(size_type n);
+    void resize(size_type n, const value_type& v);
+    void clear() noexcept;
+
+    void splice_after(const_iterator p, forward_list& x);
+    void splice_after(const_iterator p, forward_list&& x);
+    void splice_after(const_iterator p, forward_list& x, const_iterator i);
+    void splice_after(const_iterator p, forward_list&& x, const_iterator i);
+    void splice_after(const_iterator p, forward_list& x,
+                      const_iterator first, const_iterator last);
+    void splice_after(const_iterator p, forward_list&& x,
+                      const_iterator first, const_iterator last);
+    void remove(const value_type& v);
+    template <class Predicate> void remove_if(Predicate pred);
+    void unique();
+    template <class BinaryPredicate> void unique(BinaryPredicate binary_pred);
+    void merge(forward_list& x);
+    void merge(forward_list&& x);
+    template <class Compare> void merge(forward_list& x, Compare comp);
+    template <class Compare> void merge(forward_list&& x, Compare comp);
+    void sort();
+    template <class Compare> void sort(Compare comp);
+    void reverse() noexcept;
+};
+
+template <class T, class Allocator>
+    bool operator==(const forward_list<T, Allocator>& x,
+                    const forward_list<T, Allocator>& y);
+
+template <class T, class Allocator>
+    bool operator< (const forward_list<T, Allocator>& x,
+                    const forward_list<T, Allocator>& y);
+
+template <class T, class Allocator>
+    bool operator!=(const forward_list<T, Allocator>& x,
+                    const forward_list<T, Allocator>& y);
+
+template <class T, class Allocator>
+    bool operator> (const forward_list<T, Allocator>& x,
+                    const forward_list<T, Allocator>& y);
+
+template <class T, class Allocator>
+    bool operator>=(const forward_list<T, Allocator>& x,
+                    const forward_list<T, Allocator>& y);
+
+template <class T, class Allocator>
+    bool operator<=(const forward_list<T, Allocator>& x,
+                    const forward_list<T, Allocator>& y);
+
+template <class T, class Allocator>
+    void swap(forward_list<T, Allocator>& x, forward_list<T, Allocator>& y)
+         noexcept(noexcept(x.swap(y)));
+
+}  // std
+
+*/
+
+#include <__config>
+
+#include <initializer_list>
+#include <memory>
+#include <limits>
+#include <iterator>
+#include <algorithm>
+
+#include <__undef_min_max>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Tp, class _VoidPtr> struct __forward_list_node;
+
+template <class _NodePtr>
+struct __forward_begin_node
+{
+    typedef __forward_begin_node __self;
+    typedef _NodePtr pointer;
+
+    pointer __next_;
+
+     _LIBCPP_INLINE_VISIBILITY __forward_begin_node() : __next_(nullptr) {}
+};
+
+template <class _Tp, class _VoidPtr>
+struct __forward_list_node
+    : public __forward_begin_node
+             <
+                 typename pointer_traits<_VoidPtr>::template
+#ifndef _LIBCPP_HAS_NO_TEMPLATE_ALIASES
+                     rebind<__forward_list_node<_Tp, _VoidPtr> >
+#else
+                     rebind<__forward_list_node<_Tp, _VoidPtr> >::other
+#endif
+             >
+{
+    typedef _Tp value_type;
+
+    value_type __value_;
+};
+
+template<class _Tp, class _Alloc> class _LIBCPP_TYPE_VIS_ONLY forward_list;
+template<class _NodeConstPtr> class _LIBCPP_TYPE_VIS_ONLY __forward_list_const_iterator;
+
+template <class _NodePtr>
+class _LIBCPP_TYPE_VIS_ONLY __forward_list_iterator
+{
+    typedef _NodePtr __node_pointer;
+
+    __node_pointer __ptr_;
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __forward_list_iterator(__node_pointer __p) _NOEXCEPT : __ptr_(__p) {}
+
+    template<class, class> friend class _LIBCPP_TYPE_VIS_ONLY forward_list;
+    template<class> friend class _LIBCPP_TYPE_VIS_ONLY __forward_list_const_iterator;
+
+public:
+    typedef forward_iterator_tag                              iterator_category;
+    typedef typename pointer_traits<__node_pointer>::element_type::value_type
+                                                              value_type;
+    typedef value_type&                                       reference;
+    typedef typename pointer_traits<__node_pointer>::difference_type
+                                                              difference_type;
+    typedef typename pointer_traits<__node_pointer>::template
+#ifndef _LIBCPP_HAS_NO_TEMPLATE_ALIASES
+            rebind<value_type>
+#else
+            rebind<value_type>::other
+#endif
+                                                              pointer;
+
+    _LIBCPP_INLINE_VISIBILITY
+    __forward_list_iterator() _NOEXCEPT : __ptr_(nullptr) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    reference operator*() const {return __ptr_->__value_;}
+    _LIBCPP_INLINE_VISIBILITY
+    pointer operator->() const {return pointer_traits<pointer>::pointer_to(__ptr_->__value_);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    __forward_list_iterator& operator++()
+    {
+        __ptr_ = __ptr_->__next_;
+        return *this;
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    __forward_list_iterator operator++(int)
+    {
+        __forward_list_iterator __t(*this);
+        ++(*this);
+        return __t;
+    }
+
+    friend _LIBCPP_INLINE_VISIBILITY
+    bool operator==(const __forward_list_iterator& __x,
+                    const __forward_list_iterator& __y)
+        {return __x.__ptr_ == __y.__ptr_;}
+    friend _LIBCPP_INLINE_VISIBILITY
+    bool operator!=(const __forward_list_iterator& __x,
+                    const __forward_list_iterator& __y)
+        {return !(__x == __y);}
+};
+
+template <class _NodeConstPtr>
+class _LIBCPP_TYPE_VIS_ONLY __forward_list_const_iterator
+{
+    typedef _NodeConstPtr __node_const_pointer;
+
+    __node_const_pointer __ptr_;
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __forward_list_const_iterator(__node_const_pointer __p) _NOEXCEPT
+        : __ptr_(__p) {}
+
+    typedef typename remove_const
+        <
+            typename pointer_traits<__node_const_pointer>::element_type
+        >::type                                               __node;
+    typedef typename pointer_traits<__node_const_pointer>::template
+#ifndef _LIBCPP_HAS_NO_TEMPLATE_ALIASES
+            rebind<__node>
+#else
+            rebind<__node>::other
+#endif
+                                                              __node_pointer;
+
+    template<class, class> friend class forward_list;
+
+public:
+    typedef forward_iterator_tag                              iterator_category;
+    typedef typename __node::value_type                       value_type;
+    typedef const value_type&                                 reference;
+    typedef typename pointer_traits<__node_const_pointer>::difference_type
+                                                              difference_type;
+    typedef typename pointer_traits<__node_const_pointer>::template
+#ifndef _LIBCPP_HAS_NO_TEMPLATE_ALIASES
+            rebind<const value_type>
+#else
+            rebind<const value_type>::other
+#endif
+                                                              pointer;
+
+    _LIBCPP_INLINE_VISIBILITY
+    __forward_list_const_iterator() _NOEXCEPT : __ptr_(nullptr) {}
+    _LIBCPP_INLINE_VISIBILITY
+    __forward_list_const_iterator(__forward_list_iterator<__node_pointer> __p) _NOEXCEPT
+        : __ptr_(__p.__ptr_) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    reference operator*() const {return __ptr_->__value_;}
+    _LIBCPP_INLINE_VISIBILITY
+    pointer operator->() const {return pointer_traits<pointer>::pointer_to(__ptr_->__value_);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    __forward_list_const_iterator& operator++()
+    {
+        __ptr_ = __ptr_->__next_;
+        return *this;
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    __forward_list_const_iterator operator++(int)
+    {
+        __forward_list_const_iterator __t(*this);
+        ++(*this);
+        return __t;
+    }
+
+    friend _LIBCPP_INLINE_VISIBILITY
+    bool operator==(const __forward_list_const_iterator& __x,
+                    const __forward_list_const_iterator& __y)
+        {return __x.__ptr_ == __y.__ptr_;}
+    friend _LIBCPP_INLINE_VISIBILITY
+    bool operator!=(const __forward_list_const_iterator& __x,
+                           const __forward_list_const_iterator& __y)
+        {return !(__x == __y);}
+};
+
+template <class _Tp, class _Alloc>
+class __forward_list_base
+{
+protected:
+    typedef _Tp    value_type;
+    typedef _Alloc allocator_type;
+
+    typedef typename allocator_traits<allocator_type>::void_pointer void_pointer;
+    typedef __forward_list_node<value_type, void_pointer>           __node;
+    typedef typename __node::__self                                 __begin_node;
+    typedef typename allocator_traits<allocator_type>::template
+#ifndef _LIBCPP_HAS_NO_TEMPLATE_ALIASES
+                rebind_alloc<__node>
+#else
+                rebind_alloc<__node>::other
+#endif
+                                                      __node_allocator;
+    typedef allocator_traits<__node_allocator>        __node_traits;
+    typedef typename __node_traits::pointer           __node_pointer;
+    typedef typename __node_traits::pointer           __node_const_pointer;
+
+    typedef typename allocator_traits<allocator_type>::template
+#ifndef _LIBCPP_HAS_NO_TEMPLATE_ALIASES
+                rebind_alloc<__begin_node>
+#else
+                rebind_alloc<__begin_node>::other
+#endif
+                                                      __begin_node_allocator;
+    typedef typename allocator_traits<__begin_node_allocator>::pointer __begin_node_pointer;
+
+    __compressed_pair<__begin_node, __node_allocator> __before_begin_;
+
+    _LIBCPP_INLINE_VISIBILITY
+    __node_pointer        __before_begin() _NOEXCEPT
+        {return static_cast<__node_pointer>(pointer_traits<__begin_node_pointer>::
+                                        pointer_to(__before_begin_.first()));}
+    _LIBCPP_INLINE_VISIBILITY
+    __node_const_pointer  __before_begin() const _NOEXCEPT
+        {return static_cast<__node_const_pointer>(pointer_traits<__begin_node_pointer>::
+                                        pointer_to(const_cast<__begin_node&>(__before_begin_.first())));}
+
+    _LIBCPP_INLINE_VISIBILITY
+          __node_allocator& __alloc() _NOEXCEPT
+            {return __before_begin_.second();}
+    _LIBCPP_INLINE_VISIBILITY
+    const __node_allocator& __alloc() const _NOEXCEPT
+        {return __before_begin_.second();}
+
+    typedef __forward_list_iterator<__node_pointer>             iterator;
+    typedef __forward_list_const_iterator<__node_pointer>       const_iterator;
+
+    _LIBCPP_INLINE_VISIBILITY
+    __forward_list_base()
+        _NOEXCEPT_(is_nothrow_default_constructible<__node_allocator>::value)
+        : __before_begin_(__begin_node()) {}
+    _LIBCPP_INLINE_VISIBILITY
+    __forward_list_base(const allocator_type& __a)
+        : __before_begin_(__begin_node(), __node_allocator(__a)) {}
+
+#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
+public:
+    __forward_list_base(__forward_list_base&& __x)
+        _NOEXCEPT_(is_nothrow_move_constructible<__node_allocator>::value);
+    __forward_list_base(__forward_list_base&& __x, const allocator_type& __a);
+#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
+
+private:
+    __forward_list_base(const __forward_list_base&);
+    __forward_list_base& operator=(const __forward_list_base&);
+
+public:
+    ~__forward_list_base();
+
+protected:
+    _LIBCPP_INLINE_VISIBILITY
+    void __copy_assign_alloc(const __forward_list_base& __x)
+        {__copy_assign_alloc(__x, integral_constant<bool,
+              __node_traits::propagate_on_container_copy_assignment::value>());}
+
+    _LIBCPP_INLINE_VISIBILITY
+    void __move_assign_alloc(__forward_list_base& __x)
+        _NOEXCEPT_(!__node_traits::propagate_on_container_move_assignment::value ||
+                   is_nothrow_move_assignable<__node_allocator>::value)
+        {__move_assign_alloc(__x, integral_constant<bool,
+              __node_traits::propagate_on_container_move_assignment::value>());}
+
+public:
+    void swap(__forward_list_base& __x)
+        _NOEXCEPT_(!__node_traits::propagate_on_container_swap::value ||
+                   __is_nothrow_swappable<__node_allocator>::value);
+protected:
+    void clear() _NOEXCEPT;
+
+private:
+    _LIBCPP_INLINE_VISIBILITY
+    void __copy_assign_alloc(const __forward_list_base&, false_type) {}
+    _LIBCPP_INLINE_VISIBILITY
+    void __copy_assign_alloc(const __forward_list_base& __x, true_type)
+    {
+        if (__alloc() != __x.__alloc())
+            clear();
+        __alloc() = __x.__alloc();
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    void __move_assign_alloc(__forward_list_base& __x, false_type) _NOEXCEPT
+        {}
+    _LIBCPP_INLINE_VISIBILITY
+    void __move_assign_alloc(__forward_list_base& __x, true_type)
+        _NOEXCEPT_(is_nothrow_move_assignable<__node_allocator>::value)
+        {__alloc() = _VSTD::move(__x.__alloc());}
+
+    _LIBCPP_INLINE_VISIBILITY
+    static void __swap_alloc(__node_allocator& __x, __node_allocator& __y)
+        _NOEXCEPT_(!__node_traits::propagate_on_container_swap::value ||
+                   __is_nothrow_swappable<__node_allocator>::value)
+        {__swap_alloc(__x, __y, integral_constant<bool,
+                         __node_traits::propagate_on_container_swap::value>());}
+    _LIBCPP_INLINE_VISIBILITY
+    static void __swap_alloc(__node_allocator& __x, __node_allocator& __y,
+                                                                     false_type)
+        _NOEXCEPT
+        {}
+    _LIBCPP_INLINE_VISIBILITY
+    static void __swap_alloc(__node_allocator& __x, __node_allocator& __y,
+                                                                      true_type)
+        _NOEXCEPT_(__is_nothrow_swappable<__node_allocator>::value)
+        {
+            using _VSTD::swap;
+            swap(__x, __y);
+        }
+};
+
+#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
+
+template <class _Tp, class _Alloc>
+inline _LIBCPP_INLINE_VISIBILITY
+__forward_list_base<_Tp, _Alloc>::__forward_list_base(__forward_list_base&& __x)
+        _NOEXCEPT_(is_nothrow_move_constructible<__node_allocator>::value)
+    : __before_begin_(_VSTD::move(__x.__before_begin_))
+{
+    __x.__before_begin()->__next_ = nullptr;
+}
+
+template <class _Tp, class _Alloc>
+inline _LIBCPP_INLINE_VISIBILITY
+__forward_list_base<_Tp, _Alloc>::__forward_list_base(__forward_list_base&& __x,
+                                                      const allocator_type& __a)
+    : __before_begin_(__begin_node(), __node_allocator(__a))
+{
+    if (__alloc() == __x.__alloc())
+    {
+        __before_begin()->__next_ = __x.__before_begin()->__next_;
+        __x.__before_begin()->__next_ = nullptr;
+    }
+}
+
+#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
+
+template <class _Tp, class _Alloc>
+__forward_list_base<_Tp, _Alloc>::~__forward_list_base()
+{
+    clear();
+}
+
+template <class _Tp, class _Alloc>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+__forward_list_base<_Tp, _Alloc>::swap(__forward_list_base& __x)
+        _NOEXCEPT_(!__node_traits::propagate_on_container_swap::value ||
+                   __is_nothrow_swappable<__node_allocator>::value)
+{
+    __swap_alloc(__alloc(), __x.__alloc());
+    using _VSTD::swap;
+    swap(__before_begin()->__next_, __x.__before_begin()->__next_);
+}
+
+template <class _Tp, class _Alloc>
+void
+__forward_list_base<_Tp, _Alloc>::clear() _NOEXCEPT
+{
+    __node_allocator& __a = __alloc();
+    for (__node_pointer __p = __before_begin()->__next_; __p != nullptr;)
+    {
+        __node_pointer __next = __p->__next_;
+        __node_traits::destroy(__a, _VSTD::addressof(__p->__value_));
+        __node_traits::deallocate(__a, __p, 1);
+        __p = __next;
+    }
+    __before_begin()->__next_ = nullptr;
+}
+
+template <class _Tp, class _Alloc = allocator<_Tp> >
+class _LIBCPP_TYPE_VIS_ONLY forward_list
+    : private __forward_list_base<_Tp, _Alloc>
+{
+    typedef __forward_list_base<_Tp, _Alloc> base;
+    typedef typename base::__node_allocator  __node_allocator;
+    typedef typename base::__node            __node;
+    typedef typename base::__node_traits     __node_traits;
+    typedef typename base::__node_pointer    __node_pointer;
+
+public:
+    typedef _Tp    value_type;
+    typedef _Alloc allocator_type;
+
+    typedef value_type&                                                reference;
+    typedef const value_type&                                          const_reference;
+    typedef typename allocator_traits<allocator_type>::pointer         pointer;
+    typedef typename allocator_traits<allocator_type>::const_pointer   const_pointer;
+    typedef typename allocator_traits<allocator_type>::size_type       size_type;
+    typedef typename allocator_traits<allocator_type>::difference_type difference_type;
+
+    typedef typename base::iterator       iterator;
+    typedef typename base::const_iterator const_iterator;
+
+    _LIBCPP_INLINE_VISIBILITY
+    forward_list()
+        _NOEXCEPT_(is_nothrow_default_constructible<__node_allocator>::value)
+        {} // = default;
+    explicit forward_list(const allocator_type& __a);
+    explicit forward_list(size_type __n);
+#if _LIBCPP_STD_VER > 11
+    explicit forward_list(size_type __n, const allocator_type& __a);
+#endif
+    forward_list(size_type __n, const value_type& __v);
+    forward_list(size_type __n, const value_type& __v, const allocator_type& __a);
+    template <class _InputIterator>
+        forward_list(_InputIterator __f, _InputIterator __l,
+                     typename enable_if<
+                       __is_input_iterator<_InputIterator>::value
+                     >::type* = nullptr);
+    template <class _InputIterator>
+        forward_list(_InputIterator __f, _InputIterator __l,
+                     const allocator_type& __a,
+                     typename enable_if<
+                       __is_input_iterator<_InputIterator>::value
+                     >::type* = nullptr);
+    forward_list(const forward_list& __x);
+    forward_list(const forward_list& __x, const allocator_type& __a);
+#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
+    _LIBCPP_INLINE_VISIBILITY
+    forward_list(forward_list&& __x)
+        _NOEXCEPT_(is_nothrow_move_constructible<base>::value)
+        : base(_VSTD::move(__x)) {}
+    forward_list(forward_list&& __x, const allocator_type& __a);
+#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
+#ifndef _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
+    forward_list(initializer_list<value_type> __il);
+    forward_list(initializer_list<value_type> __il, const allocator_type& __a);
+#endif  // _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
+
+    // ~forward_list() = default;
+
+    forward_list& operator=(const forward_list& __x);
+#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
+    forward_list& operator=(forward_list&& __x)
+        _NOEXCEPT_(
+             __node_traits::propagate_on_container_move_assignment::value &&
+             is_nothrow_move_assignable<allocator_type>::value);
+#endif
+#ifndef  _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
+    forward_list& operator=(initializer_list<value_type> __il);
+#endif  // _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
+
+    template <class _InputIterator>
+        typename enable_if
+        <
+            __is_input_iterator<_InputIterator>::value,
+            void
+        >::type
+        assign(_InputIterator __f, _InputIterator __l);
+    void assign(size_type __n, const value_type& __v);
+#ifndef _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
+    void assign(initializer_list<value_type> __il);
+#endif  // _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
+
+    _LIBCPP_INLINE_VISIBILITY
+    allocator_type get_allocator() const _NOEXCEPT
+        {return allocator_type(base::__alloc());}
+
+    _LIBCPP_INLINE_VISIBILITY
+    iterator       begin() _NOEXCEPT
+        {return       iterator(base::__before_begin()->__next_);}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator begin() const _NOEXCEPT
+        {return const_iterator(base::__before_begin()->__next_);}
+    _LIBCPP_INLINE_VISIBILITY
+    iterator       end() _NOEXCEPT
+        {return       iterator(nullptr);}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator end() const _NOEXCEPT
+        {return const_iterator(nullptr);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator cbegin() const _NOEXCEPT
+        {return const_iterator(base::__before_begin()->__next_);}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator cend() const _NOEXCEPT
+        {return const_iterator(nullptr);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    iterator       before_begin() _NOEXCEPT
+        {return       iterator(base::__before_begin());}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator before_begin() const _NOEXCEPT
+        {return const_iterator(base::__before_begin());}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator cbefore_begin() const _NOEXCEPT
+        {return const_iterator(base::__before_begin());}
+
+    _LIBCPP_INLINE_VISIBILITY
+    bool empty() const _NOEXCEPT
+        {return base::__before_begin()->__next_ == nullptr;}
+    _LIBCPP_INLINE_VISIBILITY
+    size_type max_size() const _NOEXCEPT
+        {return numeric_limits<size_type>::max();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    reference       front()       {return base::__before_begin()->__next_->__value_;}
+    _LIBCPP_INLINE_VISIBILITY
+    const_reference front() const {return base::__before_begin()->__next_->__value_;}
+
+#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
+#ifndef _LIBCPP_HAS_NO_VARIADICS
+    template <class... _Args> void emplace_front(_Args&&... __args);
+#endif
+    void push_front(value_type&& __v);
+#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
+    void push_front(const value_type& __v);
+
+    void pop_front();
+
+#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
+#ifndef _LIBCPP_HAS_NO_VARIADICS
+    template <class... _Args>
+        iterator emplace_after(const_iterator __p, _Args&&... __args);
+#endif  // _LIBCPP_HAS_NO_VARIADICS
+    iterator insert_after(const_iterator __p, value_type&& __v);
+#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
+    iterator insert_after(const_iterator __p, const value_type& __v);
+    iterator insert_after(const_iterator __p, size_type __n, const value_type& __v);
+    template <class _InputIterator>
+        _LIBCPP_INLINE_VISIBILITY
+        typename enable_if
+        <
+            __is_input_iterator<_InputIterator>::value,
+            iterator
+        >::type
+        insert_after(const_iterator __p, _InputIterator __f, _InputIterator __l);
+#ifndef _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
+    iterator insert_after(const_iterator __p, initializer_list<value_type> __il)
+        {return insert_after(__p, __il.begin(), __il.end());}
+#endif  // _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
+
+    iterator erase_after(const_iterator __p);
+    iterator erase_after(const_iterator __f, const_iterator __l);
+
+    _LIBCPP_INLINE_VISIBILITY
+    void swap(forward_list& __x)
+        _NOEXCEPT_(!__node_traits::propagate_on_container_swap::value ||
+                   __is_nothrow_swappable<__node_allocator>::value)
+        {base::swap(__x);}
+
+    void resize(size_type __n);
+    void resize(size_type __n, const value_type& __v);
+    _LIBCPP_INLINE_VISIBILITY
+    void clear() _NOEXCEPT {base::clear();}
+
+#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
+    _LIBCPP_INLINE_VISIBILITY
+    void splice_after(const_iterator __p, forward_list&& __x);
+    _LIBCPP_INLINE_VISIBILITY
+    void splice_after(const_iterator __p, forward_list&& __x, const_iterator __i);
+    _LIBCPP_INLINE_VISIBILITY
+    void splice_after(const_iterator __p, forward_list&& __x,
+                      const_iterator __f, const_iterator __l);
+#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
+    void splice_after(const_iterator __p, forward_list& __x);
+    void splice_after(const_iterator __p, forward_list& __x, const_iterator __i);
+    void splice_after(const_iterator __p, forward_list& __x,
+                      const_iterator __f, const_iterator __l);
+    void remove(const value_type& __v);
+    template <class _Predicate> void remove_if(_Predicate __pred);
+    _LIBCPP_INLINE_VISIBILITY
+    void unique() {unique(__equal_to<value_type>());}
+    template <class _BinaryPredicate> void unique(_BinaryPredicate __binary_pred);
+#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
+    _LIBCPP_INLINE_VISIBILITY
+    void merge(forward_list&& __x) {merge(__x, __less<value_type>());}
+    template <class _Compare>
+        _LIBCPP_INLINE_VISIBILITY
+        void merge(forward_list&& __x, _Compare __comp)
+        {merge(__x, _VSTD::move(__comp));}
+#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
+    _LIBCPP_INLINE_VISIBILITY
+    void merge(forward_list& __x) {merge(__x, __less<value_type>());}
+    template <class _Compare> void merge(forward_list& __x, _Compare __comp);
+    _LIBCPP_INLINE_VISIBILITY
+    void sort() {sort(__less<value_type>());}
+    template <class _Compare> void sort(_Compare __comp);
+    void reverse() _NOEXCEPT;
+
+private:
+
+#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
+    void __move_assign(forward_list& __x, true_type)
+        _NOEXCEPT_(is_nothrow_move_assignable<allocator_type>::value);
+    void __move_assign(forward_list& __x, false_type);
+#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
+
+    template <class _Compare>
+        static
+        __node_pointer
+        __merge(__node_pointer __f1, __node_pointer __f2, _Compare& __comp);
+
+    template <class _Compare>
+        static
+        __node_pointer
+        __sort(__node_pointer __f, difference_type __sz, _Compare& __comp);
+};
+
+template <class _Tp, class _Alloc>
+inline _LIBCPP_INLINE_VISIBILITY
+forward_list<_Tp, _Alloc>::forward_list(const allocator_type& __a)
+    : base(__a)
+{
+}
+
+template <class _Tp, class _Alloc>
+forward_list<_Tp, _Alloc>::forward_list(size_type __n)
+{
+    if (__n > 0)
+    {
+        __node_allocator& __a = base::__alloc();
+        typedef __allocator_destructor<__node_allocator> _Dp;
+        unique_ptr<__node, _Dp> __h(nullptr, _Dp(__a, 1));
+        for (__node_pointer __p = base::__before_begin(); __n > 0; --__n,
+                                                             __p = __p->__next_)
+        {
+            __h.reset(__node_traits::allocate(__a, 1));
+            __node_traits::construct(__a, _VSTD::addressof(__h->__value_));
+            __h->__next_ = nullptr;
+            __p->__next_ = __h.release();
+        }
+    }
+}
+
+#if _LIBCPP_STD_VER > 11
+template <class _Tp, class _Alloc>
+forward_list<_Tp, _Alloc>::forward_list(size_type __n, const allocator_type& __a)
+    : base ( __a )
+{
+    if (__n > 0)
+    {
+        __node_allocator& __a = base::__alloc();
+        typedef __allocator_destructor<__node_allocator> _Dp;
+        unique_ptr<__node, _Dp> __h(nullptr, _Dp(__a, 1));
+        for (__node_pointer __p = base::__before_begin(); __n > 0; --__n,
+                                                             __p = __p->__next_)
+        {
+            __h.reset(__node_traits::allocate(__a, 1));
+            __node_traits::construct(__a, _VSTD::addressof(__h->__value_));
+            __h->__next_ = nullptr;
+            __p->__next_ = __h.release();
+        }
+    }
+}
+#endif
+
+template <class _Tp, class _Alloc>
+forward_list<_Tp, _Alloc>::forward_list(size_type __n, const value_type& __v)
+{
+    insert_after(cbefore_begin(), __n, __v);
+}
+
+template <class _Tp, class _Alloc>
+forward_list<_Tp, _Alloc>::forward_list(size_type __n, const value_type& __v,
+                                        const allocator_type& __a)
+    : base(__a)
+{
+    insert_after(cbefore_begin(), __n, __v);
+}
+
+template <class _Tp, class _Alloc>
+template <class _InputIterator>
+forward_list<_Tp, _Alloc>::forward_list(_InputIterator __f, _InputIterator __l,
+                                        typename enable_if<
+                                          __is_input_iterator<_InputIterator>::value
+                                        >::type*)
+{
+    insert_after(cbefore_begin(), __f, __l);
+}
+
+template <class _Tp, class _Alloc>
+template <class _InputIterator>
+forward_list<_Tp, _Alloc>::forward_list(_InputIterator __f, _InputIterator __l,
+                                        const allocator_type& __a,
+                                        typename enable_if<
+                                          __is_input_iterator<_InputIterator>::value
+                                        >::type*)
+    : base(__a)
+{
+    insert_after(cbefore_begin(), __f, __l);
+}
+
+template <class _Tp, class _Alloc>
+forward_list<_Tp, _Alloc>::forward_list(const forward_list& __x)
+    : base(allocator_type(
+             __node_traits::select_on_container_copy_construction(__x.__alloc())
+                         )
+          )
+{
+    insert_after(cbefore_begin(), __x.begin(), __x.end());
+}
+
+template <class _Tp, class _Alloc>
+forward_list<_Tp, _Alloc>::forward_list(const forward_list& __x,
+                                        const allocator_type& __a)
+    : base(__a)
+{
+    insert_after(cbefore_begin(), __x.begin(), __x.end());
+}
+
+#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
+
+template <class _Tp, class _Alloc>
+forward_list<_Tp, _Alloc>::forward_list(forward_list&& __x,
+                                        const allocator_type& __a)
+    : base(_VSTD::move(__x), __a)
+{
+    if (base::__alloc() != __x.__alloc())
+    {
+        typedef move_iterator<iterator> _Ip;
+        insert_after(cbefore_begin(), _Ip(__x.begin()), _Ip(__x.end()));
+    }
+}
+
+#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
+
+#ifndef _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
+
+template <class _Tp, class _Alloc>
+forward_list<_Tp, _Alloc>::forward_list(initializer_list<value_type> __il)
+{
+    insert_after(cbefore_begin(), __il.begin(), __il.end());
+}
+
+template <class _Tp, class _Alloc>
+forward_list<_Tp, _Alloc>::forward_list(initializer_list<value_type> __il,
+                                        const allocator_type& __a)
+    : base(__a)
+{
+    insert_after(cbefore_begin(), __il.begin(), __il.end());
+}
+
+#endif  // _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
+
+template <class _Tp, class _Alloc>
+forward_list<_Tp, _Alloc>&
+forward_list<_Tp, _Alloc>::operator=(const forward_list& __x)
+{
+    if (this != &__x)
+    {
+        base::__copy_assign_alloc(__x);
+        assign(__x.begin(), __x.end());
+    }
+    return *this;
+}
+
+#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
+
+template <class _Tp, class _Alloc>
+void
+forward_list<_Tp, _Alloc>::__move_assign(forward_list& __x, true_type)
+    _NOEXCEPT_(is_nothrow_move_assignable<allocator_type>::value)
+{
+    clear();
+    base::__move_assign_alloc(__x);
+    base::__before_begin()->__next_ = __x.__before_begin()->__next_;
+    __x.__before_begin()->__next_ = nullptr;
+}
+
+template <class _Tp, class _Alloc>
+void
+forward_list<_Tp, _Alloc>::__move_assign(forward_list& __x, false_type)
+{
+    if (base::__alloc() == __x.__alloc())
+        __move_assign(__x, true_type());
+    else
+    {
+        typedef move_iterator<iterator> _Ip;
+        assign(_Ip(__x.begin()), _Ip(__x.end()));
+    }
+}
+
+template <class _Tp, class _Alloc>
+inline _LIBCPP_INLINE_VISIBILITY
+forward_list<_Tp, _Alloc>&
+forward_list<_Tp, _Alloc>::operator=(forward_list&& __x)
+    _NOEXCEPT_(
+             __node_traits::propagate_on_container_move_assignment::value &&
+             is_nothrow_move_assignable<allocator_type>::value)
+{
+    __move_assign(__x, integral_constant<bool,
+          __node_traits::propagate_on_container_move_assignment::value>());
+    return *this;
+}
+
+#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
+
+#ifndef _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
+
+template <class _Tp, class _Alloc>
+inline _LIBCPP_INLINE_VISIBILITY
+forward_list<_Tp, _Alloc>&
+forward_list<_Tp, _Alloc>::operator=(initializer_list<value_type> __il)
+{
+    assign(__il.begin(), __il.end());
+    return *this;
+}
+
+#endif  // _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
+
+template <class _Tp, class _Alloc>
+template <class _InputIterator>
+typename enable_if
+<
+    __is_input_iterator<_InputIterator>::value,
+    void
+>::type
+forward_list<_Tp, _Alloc>::assign(_InputIterator __f, _InputIterator __l)
+{
+    iterator __i = before_begin();
+    iterator __j = _VSTD::next(__i);
+    iterator __e = end();
+    for (; __j != __e && __f != __l; ++__i, ++__j, ++__f)
+        *__j = *__f;
+    if (__j == __e)
+        insert_after(__i, __f, __l);
+    else
+        erase_after(__i, __e);
+}
+
+template <class _Tp, class _Alloc>
+void
+forward_list<_Tp, _Alloc>::assign(size_type __n, const value_type& __v)
+{
+    iterator __i = before_begin();
+    iterator __j = _VSTD::next(__i);
+    iterator __e = end();
+    for (; __j != __e && __n > 0; --__n, ++__i, ++__j)
+        *__j = __v;
+    if (__j == __e)
+        insert_after(__i, __n, __v);
+    else
+        erase_after(__i, __e);
+}
+
+#ifndef _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
+
+template <class _Tp, class _Alloc>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+forward_list<_Tp, _Alloc>::assign(initializer_list<value_type> __il)
+{
+    assign(__il.begin(), __il.end());
+}
+
+#endif  // _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
+
+#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
+#ifndef _LIBCPP_HAS_NO_VARIADICS
+
+template <class _Tp, class _Alloc>
+template <class... _Args>
+void
+forward_list<_Tp, _Alloc>::emplace_front(_Args&&... __args)
+{
+    __node_allocator& __a = base::__alloc();
+    typedef __allocator_destructor<__node_allocator> _Dp;
+    unique_ptr<__node, _Dp> __h(__node_traits::allocate(__a, 1), _Dp(__a, 1));
+    __node_traits::construct(__a, _VSTD::addressof(__h->__value_),
+                                  _VSTD::forward<_Args>(__args)...);
+    __h->__next_ = base::__before_begin()->__next_;
+    base::__before_begin()->__next_ = __h.release();
+}
+
+#endif  // _LIBCPP_HAS_NO_VARIADICS
+
+template <class _Tp, class _Alloc>
+void
+forward_list<_Tp, _Alloc>::push_front(value_type&& __v)
+{
+    __node_allocator& __a = base::__alloc();
+    typedef __allocator_destructor<__node_allocator> _Dp;
+    unique_ptr<__node, _Dp> __h(__node_traits::allocate(__a, 1), _Dp(__a, 1));
+    __node_traits::construct(__a, _VSTD::addressof(__h->__value_), _VSTD::move(__v));
+    __h->__next_ = base::__before_begin()->__next_;
+    base::__before_begin()->__next_ = __h.release();
+}
+
+#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
+
+template <class _Tp, class _Alloc>
+void
+forward_list<_Tp, _Alloc>::push_front(const value_type& __v)
+{
+    __node_allocator& __a = base::__alloc();
+    typedef __allocator_destructor<__node_allocator> _Dp;
+    unique_ptr<__node, _Dp> __h(__node_traits::allocate(__a, 1), _Dp(__a, 1));
+    __node_traits::construct(__a, _VSTD::addressof(__h->__value_), __v);
+    __h->__next_ = base::__before_begin()->__next_;
+    base::__before_begin()->__next_ = __h.release();
+}
+
+template <class _Tp, class _Alloc>
+void
+forward_list<_Tp, _Alloc>::pop_front()
+{
+    __node_allocator& __a = base::__alloc();
+    __node_pointer __p = base::__before_begin()->__next_;
+    base::__before_begin()->__next_ = __p->__next_;
+    __node_traits::destroy(__a, _VSTD::addressof(__p->__value_));
+    __node_traits::deallocate(__a, __p, 1);
+}
+
+#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
+#ifndef _LIBCPP_HAS_NO_VARIADICS
+
+template <class _Tp, class _Alloc>
+template <class... _Args>
+typename forward_list<_Tp, _Alloc>::iterator
+forward_list<_Tp, _Alloc>::emplace_after(const_iterator __p, _Args&&... __args)
+{
+    __node_pointer const __r = __p.__ptr_;
+    __node_allocator& __a = base::__alloc();
+    typedef __allocator_destructor<__node_allocator> _Dp;
+    unique_ptr<__node, _Dp> __h(__node_traits::allocate(__a, 1), _Dp(__a, 1));
+    __node_traits::construct(__a, _VSTD::addressof(__h->__value_),
+                                  _VSTD::forward<_Args>(__args)...);
+    __h->__next_ = __r->__next_;
+    __r->__next_ = __h.release();
+    return iterator(__r->__next_);
+}
+
+#endif  // _LIBCPP_HAS_NO_VARIADICS
+
+template <class _Tp, class _Alloc>
+typename forward_list<_Tp, _Alloc>::iterator
+forward_list<_Tp, _Alloc>::insert_after(const_iterator __p, value_type&& __v)
+{
+    __node_pointer const __r = __p.__ptr_;
+    __node_allocator& __a = base::__alloc();
+    typedef __allocator_destructor<__node_allocator> _Dp;
+    unique_ptr<__node, _Dp> __h(__node_traits::allocate(__a, 1), _Dp(__a, 1));
+    __node_traits::construct(__a, _VSTD::addressof(__h->__value_), _VSTD::move(__v));
+    __h->__next_ = __r->__next_;
+    __r->__next_ = __h.release();
+    return iterator(__r->__next_);
+}
+
+#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
+
+template <class _Tp, class _Alloc>
+typename forward_list<_Tp, _Alloc>::iterator
+forward_list<_Tp, _Alloc>::insert_after(const_iterator __p, const value_type& __v)
+{
+    __node_pointer const __r = __p.__ptr_;
+    __node_allocator& __a = base::__alloc();
+    typedef __allocator_destructor<__node_allocator> _Dp;
+    unique_ptr<__node, _Dp> __h(__node_traits::allocate(__a, 1), _Dp(__a, 1));
+    __node_traits::construct(__a, _VSTD::addressof(__h->__value_), __v);
+    __h->__next_ = __r->__next_;
+    __r->__next_ = __h.release();
+    return iterator(__r->__next_);
+}
+
+template <class _Tp, class _Alloc>
+typename forward_list<_Tp, _Alloc>::iterator
+forward_list<_Tp, _Alloc>::insert_after(const_iterator __p, size_type __n,
+                                        const value_type& __v)
+{
+    __node_pointer __r = __p.__ptr_;
+    if (__n > 0)
+    {
+        __node_allocator& __a = base::__alloc();
+        typedef __allocator_destructor<__node_allocator> _Dp;
+        unique_ptr<__node, _Dp> __h(__node_traits::allocate(__a, 1), _Dp(__a, 1));
+        __node_traits::construct(__a, _VSTD::addressof(__h->__value_), __v);
+        __node_pointer __first = __h.release();
+        __node_pointer __last = __first;
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        try
+        {
+#endif  // _LIBCPP_NO_EXCEPTIONS
+            for (--__n; __n != 0; --__n, __last = __last->__next_)
+            {
+                __h.reset(__node_traits::allocate(__a, 1));
+                __node_traits::construct(__a, _VSTD::addressof(__h->__value_), __v);
+                __last->__next_ = __h.release();
+            }
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        }
+        catch (...)
+        {
+            while (__first != nullptr)
+            {
+                __node_pointer __next = __first->__next_;
+                __node_traits::destroy(__a, _VSTD::addressof(__first->__value_));
+                __node_traits::deallocate(__a, __first, 1);
+                __first = __next;
+            }
+            throw;
+        }
+#endif  // _LIBCPP_NO_EXCEPTIONS
+        __last->__next_ = __r->__next_;
+        __r->__next_ = __first;
+        __r = __last;
+    }
+    return iterator(__r);
+}
+
+template <class _Tp, class _Alloc>
+template <class _InputIterator>
+typename enable_if
+<
+    __is_input_iterator<_InputIterator>::value,
+    typename forward_list<_Tp, _Alloc>::iterator
+>::type
+forward_list<_Tp, _Alloc>::insert_after(const_iterator __p,
+                                        _InputIterator __f, _InputIterator __l)
+{
+    __node_pointer __r = __p.__ptr_;
+    if (__f != __l)
+    {
+        __node_allocator& __a = base::__alloc();
+        typedef __allocator_destructor<__node_allocator> _Dp;
+        unique_ptr<__node, _Dp> __h(__node_traits::allocate(__a, 1), _Dp(__a, 1));
+        __node_traits::construct(__a, _VSTD::addressof(__h->__value_), *__f);
+        __node_pointer __first = __h.release();
+        __node_pointer __last = __first;
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        try
+        {
+#endif  // _LIBCPP_NO_EXCEPTIONS
+            for (++__f; __f != __l; ++__f, __last = __last->__next_)
+            {
+                __h.reset(__node_traits::allocate(__a, 1));
+                __node_traits::construct(__a, _VSTD::addressof(__h->__value_), *__f);
+                __last->__next_ = __h.release();
+            }
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        }
+        catch (...)
+        {
+            while (__first != nullptr)
+            {
+                __node_pointer __next = __first->__next_;
+                __node_traits::destroy(__a, _VSTD::addressof(__first->__value_));
+                __node_traits::deallocate(__a, __first, 1);
+                __first = __next;
+            }
+            throw;
+        }
+#endif  // _LIBCPP_NO_EXCEPTIONS
+        __last->__next_ = __r->__next_;
+        __r->__next_ = __first;
+        __r = __last;
+    }
+    return iterator(__r);
+}
+
+template <class _Tp, class _Alloc>
+typename forward_list<_Tp, _Alloc>::iterator
+forward_list<_Tp, _Alloc>::erase_after(const_iterator __f)
+{
+    __node_pointer __p = __f.__ptr_;
+    __node_pointer __n = __p->__next_;
+    __p->__next_ = __n->__next_;
+    __node_allocator& __a = base::__alloc();
+    __node_traits::destroy(__a, _VSTD::addressof(__n->__value_));
+    __node_traits::deallocate(__a, __n, 1);
+    return iterator(__p->__next_);
+}
+
+template <class _Tp, class _Alloc>
+typename forward_list<_Tp, _Alloc>::iterator
+forward_list<_Tp, _Alloc>::erase_after(const_iterator __f, const_iterator __l)
+{
+    __node_pointer __e = __l.__ptr_;
+    if (__f != __l)
+    {
+        __node_pointer __p = __f.__ptr_;
+        __node_pointer __n = __p->__next_;
+        if (__n != __e)
+        {
+            __p->__next_ = __e;
+            __node_allocator& __a = base::__alloc();
+            do
+            {
+                __p = __n->__next_;
+                __node_traits::destroy(__a, _VSTD::addressof(__n->__value_));
+                __node_traits::deallocate(__a, __n, 1);
+                __n = __p;
+            } while (__n != __e);
+        }
+    }
+    return iterator(__e);
+}
+
+template <class _Tp, class _Alloc>
+void
+forward_list<_Tp, _Alloc>::resize(size_type __n)
+{
+    size_type __sz = 0;
+    iterator __p = before_begin();
+    iterator __i = begin();
+    iterator __e = end();
+    for (; __i != __e && __sz < __n; ++__p, ++__i, ++__sz)
+        ;
+    if (__i != __e)
+        erase_after(__p, __e);
+    else
+    {
+        __n -= __sz;
+        if (__n > 0)
+        {
+            __node_allocator& __a = base::__alloc();
+            typedef __allocator_destructor<__node_allocator> _Dp;
+            unique_ptr<__node, _Dp> __h(nullptr, _Dp(__a, 1));
+            for (__node_pointer __ptr = __p.__ptr_; __n > 0; --__n,
+                                                         __ptr = __ptr->__next_)
+            {
+                __h.reset(__node_traits::allocate(__a, 1));
+                __node_traits::construct(__a, _VSTD::addressof(__h->__value_));
+                __h->__next_ = nullptr;
+                __ptr->__next_ = __h.release();
+            }
+        }
+    }
+}
+
+template <class _Tp, class _Alloc>
+void
+forward_list<_Tp, _Alloc>::resize(size_type __n, const value_type& __v)
+{
+    size_type __sz = 0;
+    iterator __p = before_begin();
+    iterator __i = begin();
+    iterator __e = end();
+    for (; __i != __e && __sz < __n; ++__p, ++__i, ++__sz)
+        ;
+    if (__i != __e)
+        erase_after(__p, __e);
+    else
+    {
+        __n -= __sz;
+        if (__n > 0)
+        {
+            __node_allocator& __a = base::__alloc();
+            typedef __allocator_destructor<__node_allocator> _Dp;
+            unique_ptr<__node, _Dp> __h(nullptr, _Dp(__a, 1));
+            for (__node_pointer __ptr = __p.__ptr_; __n > 0; --__n,
+                                                         __ptr = __ptr->__next_)
+            {
+                __h.reset(__node_traits::allocate(__a, 1));
+                __node_traits::construct(__a, _VSTD::addressof(__h->__value_), __v);
+                __h->__next_ = nullptr;
+                __ptr->__next_ = __h.release();
+            }
+        }
+    }
+}
+
+template <class _Tp, class _Alloc>
+void
+forward_list<_Tp, _Alloc>::splice_after(const_iterator __p,
+                                        forward_list& __x)
+{
+    if (!__x.empty())
+    {
+        if (__p.__ptr_->__next_ != nullptr)
+        {
+            const_iterator __lm1 = __x.before_begin();
+            while (__lm1.__ptr_->__next_ != nullptr)
+                ++__lm1;
+            __lm1.__ptr_->__next_ = __p.__ptr_->__next_;
+        }
+        __p.__ptr_->__next_ = __x.__before_begin()->__next_;
+        __x.__before_begin()->__next_ = nullptr;
+    }
+}
+
+template <class _Tp, class _Alloc>
+void
+forward_list<_Tp, _Alloc>::splice_after(const_iterator __p,
+                                        forward_list& __x,
+                                        const_iterator __i)
+{
+    const_iterator __lm1 = _VSTD::next(__i);
+    if (__p != __i && __p != __lm1)
+    {
+        __i.__ptr_->__next_ = __lm1.__ptr_->__next_;
+        __lm1.__ptr_->__next_ = __p.__ptr_->__next_;
+        __p.__ptr_->__next_ = __lm1.__ptr_;
+    }
+}
+
+template <class _Tp, class _Alloc>
+void
+forward_list<_Tp, _Alloc>::splice_after(const_iterator __p,
+                                        forward_list& __x,
+                                        const_iterator __f, const_iterator __l)
+{
+    if (__f != __l && __p != __f)
+    {
+        const_iterator __lm1 = __f;
+        while (__lm1.__ptr_->__next_ != __l.__ptr_)
+            ++__lm1;
+        if (__f != __lm1)
+        {
+            __lm1.__ptr_->__next_ = __p.__ptr_->__next_;
+            __p.__ptr_->__next_ = __f.__ptr_->__next_;
+            __f.__ptr_->__next_ = __l.__ptr_;
+        }
+    }
+}
+
+#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
+
+template <class _Tp, class _Alloc>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+forward_list<_Tp, _Alloc>::splice_after(const_iterator __p,
+                                        forward_list&& __x)
+{
+    splice_after(__p, __x);
+}
+
+template <class _Tp, class _Alloc>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+forward_list<_Tp, _Alloc>::splice_after(const_iterator __p,
+                                        forward_list&& __x,
+                                        const_iterator __i)
+{
+    splice_after(__p, __x, __i);
+}
+
+template <class _Tp, class _Alloc>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+forward_list<_Tp, _Alloc>::splice_after(const_iterator __p,
+                                        forward_list&& __x,
+                                        const_iterator __f, const_iterator __l)
+{
+    splice_after(__p, __x, __f, __l);
+}
+
+#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
+
+template <class _Tp, class _Alloc>
+void
+forward_list<_Tp, _Alloc>::remove(const value_type& __v)
+{
+    iterator __e = end();
+    for (iterator __i = before_begin(); __i.__ptr_->__next_ != nullptr;)
+    {
+        if (__i.__ptr_->__next_->__value_ == __v)
+        {
+            iterator __j = _VSTD::next(__i, 2);
+            for (; __j != __e && *__j == __v; ++__j)
+                ;
+            erase_after(__i, __j);
+            if (__j == __e)
+                break;
+            __i = __j;
+        }
+        else
+            ++__i;
+    }
+}
+
+template <class _Tp, class _Alloc>
+template <class _Predicate>
+void
+forward_list<_Tp, _Alloc>::remove_if(_Predicate __pred)
+{
+    iterator __e = end();
+    for (iterator __i = before_begin(); __i.__ptr_->__next_ != nullptr;)
+    {
+        if (__pred(__i.__ptr_->__next_->__value_))
+        {
+            iterator __j = _VSTD::next(__i, 2);
+            for (; __j != __e && __pred(*__j); ++__j)
+                ;
+            erase_after(__i, __j);
+            if (__j == __e)
+                break;
+            __i = __j;
+        }
+        else
+            ++__i;
+    }
+}
+
+template <class _Tp, class _Alloc>
+template <class _BinaryPredicate>
+void
+forward_list<_Tp, _Alloc>::unique(_BinaryPredicate __binary_pred)
+{
+    for (iterator __i = begin(), __e = end(); __i != __e;)
+    {
+        iterator __j = _VSTD::next(__i);
+        for (; __j != __e && __binary_pred(*__i, *__j); ++__j)
+            ;
+        if (__i.__ptr_->__next_ != __j.__ptr_)
+            erase_after(__i, __j);
+        __i = __j;
+    }
+}
+
+template <class _Tp, class _Alloc>
+template <class _Compare>
+void
+forward_list<_Tp, _Alloc>::merge(forward_list& __x, _Compare __comp)
+{
+    if (this != &__x)
+    {
+        base::__before_begin()->__next_ = __merge(base::__before_begin()->__next_,
+                                                    __x.__before_begin()->__next_,
+                                                    __comp);
+        __x.__before_begin()->__next_ = nullptr;
+    }
+}
+
+template <class _Tp, class _Alloc>
+template <class _Compare>
+typename forward_list<_Tp, _Alloc>::__node_pointer
+forward_list<_Tp, _Alloc>::__merge(__node_pointer __f1, __node_pointer __f2,
+                                   _Compare& __comp)
+{
+    if (__f1 == nullptr)
+        return __f2;
+    if (__f2 == nullptr)
+        return __f1;
+    __node_pointer __r;
+    if (__comp(__f2->__value_, __f1->__value_))
+    {
+        __node_pointer __t = __f2;
+        while (__t->__next_ != nullptr &&
+                             __comp(__t->__next_->__value_, __f1->__value_))
+            __t = __t->__next_;
+        __r = __f2;
+        __f2 = __t->__next_;
+        __t->__next_ = __f1;
+    }
+    else
+        __r = __f1;
+    __node_pointer __p = __f1;
+    __f1 = __f1->__next_;
+    while (__f1 != nullptr && __f2 != nullptr)
+    {
+        if (__comp(__f2->__value_, __f1->__value_))
+        {
+            __node_pointer __t = __f2;
+            while (__t->__next_ != nullptr &&
+                                 __comp(__t->__next_->__value_, __f1->__value_))
+                __t = __t->__next_;
+            __p->__next_ = __f2;
+            __f2 = __t->__next_;
+            __t->__next_ = __f1;
+        }
+        __p = __f1;
+        __f1 = __f1->__next_;
+    }
+    if (__f2 != nullptr)
+        __p->__next_ = __f2;
+    return __r;
+}
+
+template <class _Tp, class _Alloc>
+template <class _Compare>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+forward_list<_Tp, _Alloc>::sort(_Compare __comp)
+{
+    base::__before_begin()->__next_ = __sort(base::__before_begin()->__next_,
+                                       _VSTD::distance(begin(), end()), __comp);
+}
+
+template <class _Tp, class _Alloc>
+template <class _Compare>
+typename forward_list<_Tp, _Alloc>::__node_pointer
+forward_list<_Tp, _Alloc>::__sort(__node_pointer __f1, difference_type __sz,
+                                  _Compare& __comp)
+{
+    switch (__sz)
+    {
+    case 0:
+    case 1:
+        return __f1;
+    case 2:
+        if (__comp(__f1->__next_->__value_, __f1->__value_))
+        {
+            __node_pointer __t = __f1->__next_;
+            __t->__next_ = __f1;
+            __f1->__next_ = nullptr;
+            __f1 = __t;
+        }
+        return __f1;
+    }
+    difference_type __sz1 = __sz / 2;
+    difference_type __sz2 = __sz - __sz1;
+    __node_pointer __t = _VSTD::next(iterator(__f1), __sz1 - 1).__ptr_;
+    __node_pointer __f2 = __t->__next_;
+    __t->__next_ = nullptr;
+    return __merge(__sort(__f1, __sz1, __comp),
+                   __sort(__f2, __sz2, __comp), __comp);
+}
+
+template <class _Tp, class _Alloc>
+void
+forward_list<_Tp, _Alloc>::reverse() _NOEXCEPT
+{
+    __node_pointer __p = base::__before_begin()->__next_;
+    if (__p != nullptr)
+    {
+        __node_pointer __f = __p->__next_;
+        __p->__next_ = nullptr;
+        while (__f != nullptr)
+        {
+            __node_pointer __t = __f->__next_;
+            __f->__next_ = __p;
+            __p = __f;
+            __f = __t;
+        }
+        base::__before_begin()->__next_ = __p;
+    }
+}
+
+template <class _Tp, class _Alloc>
+bool operator==(const forward_list<_Tp, _Alloc>& __x,
+                const forward_list<_Tp, _Alloc>& __y)
+{
+    typedef forward_list<_Tp, _Alloc> _Cp;
+    typedef typename _Cp::const_iterator _Ip;
+    _Ip __ix = __x.begin();
+    _Ip __ex = __x.end();
+    _Ip __iy = __y.begin();
+    _Ip __ey = __y.end();
+    for (; __ix != __ex && __iy != __ey; ++__ix, ++__iy)
+        if (!(*__ix == *__iy))
+            return false;
+    return (__ix == __ex) == (__iy == __ey);
+}
+
+template <class _Tp, class _Alloc>
+inline _LIBCPP_INLINE_VISIBILITY
+bool operator!=(const forward_list<_Tp, _Alloc>& __x,
+                const forward_list<_Tp, _Alloc>& __y)
+{
+    return !(__x == __y);
+}
+
+template <class _Tp, class _Alloc>
+inline _LIBCPP_INLINE_VISIBILITY
+bool operator< (const forward_list<_Tp, _Alloc>& __x,
+                const forward_list<_Tp, _Alloc>& __y)
+{
+    return _VSTD::lexicographical_compare(__x.begin(), __x.end(),
+                                         __y.begin(), __y.end());
+}
+
+template <class _Tp, class _Alloc>
+inline _LIBCPP_INLINE_VISIBILITY
+bool operator> (const forward_list<_Tp, _Alloc>& __x,
+                const forward_list<_Tp, _Alloc>& __y)
+{
+    return __y < __x;
+}
+
+template <class _Tp, class _Alloc>
+inline _LIBCPP_INLINE_VISIBILITY
+bool operator>=(const forward_list<_Tp, _Alloc>& __x,
+                const forward_list<_Tp, _Alloc>& __y)
+{
+    return !(__x < __y);
+}
+
+template <class _Tp, class _Alloc>
+inline _LIBCPP_INLINE_VISIBILITY
+bool operator<=(const forward_list<_Tp, _Alloc>& __x,
+                const forward_list<_Tp, _Alloc>& __y)
+{
+    return !(__y < __x);
+}
+
+template <class _Tp, class _Alloc>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+swap(forward_list<_Tp, _Alloc>& __x, forward_list<_Tp, _Alloc>& __y)
+    _NOEXCEPT_(_NOEXCEPT_(__x.swap(__y)))
+{
+    __x.swap(__y);
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif  // _LIBCPP_FORWARD_LIST