Freeze libcxx for cuda without c++20 support

commit_hash:c2eb32b5cb16638c17c6fc6900738f26ba6eca49

1 files changed, 4501 insertions, 0 deletions

diff --git a/contrib/libs/cxxsupp/libcxxcuda11/include/string b/contrib/libs/cxxsupp/libcxxcuda11/include/string
new file mode 100644
index 00000000000..6550f5baf6b
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxxcuda11/include/string
@@ -0,0 +1,4501 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_STRING
+#define _LIBCPP_STRING
+
+/*
+    string synopsis
+
+#include <compare>
+#include <initializer_list>
+
+namespace std
+{
+
+template <class stateT>
+class fpos
+{
+private:
+    stateT st;
+public:
+    fpos(streamoff = streamoff());
+
+    operator streamoff() const;
+
+    stateT state() const;
+    void state(stateT);
+
+    fpos& operator+=(streamoff);
+    fpos  operator+ (streamoff) const;
+    fpos& operator-=(streamoff);
+    fpos  operator- (streamoff) const;
+};
+
+template <class stateT> streamoff operator-(const fpos<stateT>& x, const fpos<stateT>& y);
+
+template <class stateT> bool operator==(const fpos<stateT>& x, const fpos<stateT>& y);
+template <class stateT> bool operator!=(const fpos<stateT>& x, const fpos<stateT>& y);
+
+template <class charT>
+struct char_traits
+{
+    using char_type           = charT;
+    using int_type            = ...;
+    using off_type            = streamoff;
+    using pos_type            = streampos;
+    using state_type          = mbstate_t;
+    using comparison_category = strong_ordering; // Since C++20 only for the specializations
+                                                 // char, wchar_t, char8_t, char16_t, and char32_t.
+
+    static void assign(char_type& c1, const char_type& c2) noexcept;
+    static constexpr bool eq(char_type c1, char_type c2) noexcept;
+    static constexpr bool lt(char_type c1, char_type c2) noexcept;
+
+    static int              compare(const char_type* s1, const char_type* s2, size_t n);
+    static size_t           length(const char_type* s);
+    static const char_type* find(const char_type* s, size_t n, const char_type& a);
+    static char_type*       move(char_type* s1, const char_type* s2, size_t n);
+    static char_type*       copy(char_type* s1, const char_type* s2, size_t n);
+    static char_type*       assign(char_type* s, size_t n, char_type a);
+
+    static constexpr int_type  not_eof(int_type c) noexcept;
+    static constexpr char_type to_char_type(int_type c) noexcept;
+    static constexpr int_type  to_int_type(char_type c) noexcept;
+    static constexpr bool      eq_int_type(int_type c1, int_type c2) noexcept;
+    static constexpr int_type  eof() noexcept;
+};
+
+template <> struct char_traits<char>;
+template <> struct char_traits<wchar_t>;
+template <> struct char_traits<char8_t>;  // C++20
+template <> struct char_traits<char16_t>;
+template <> struct char_traits<char32_t>;
+
+template<class charT, class traits = char_traits<charT>, class Allocator = allocator<charT> >
+class basic_string
+{
+public:
+// types:
+    typedef traits traits_type;
+    typedef typename traits_type::char_type value_type;
+    typedef Allocator allocator_type;
+    typedef typename allocator_type::size_type size_type;
+    typedef typename allocator_type::difference_type difference_type;
+    typedef typename allocator_type::reference reference;
+    typedef typename allocator_type::const_reference const_reference;
+    typedef typename allocator_type::pointer pointer;
+    typedef typename allocator_type::const_pointer const_pointer;
+    typedef implementation-defined iterator;
+    typedef implementation-defined const_iterator;
+    typedef std::reverse_iterator<iterator> reverse_iterator;
+    typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
+
+    static const size_type npos = -1;
+
+    basic_string()
+        noexcept(is_nothrow_default_constructible<allocator_type>::value);                      // constexpr since C++20
+    explicit basic_string(const allocator_type& a);                                             // constexpr since C++20
+    basic_string(const basic_string& str);                                                      // constexpr since C++20
+    basic_string(basic_string&& str)
+        noexcept(is_nothrow_move_constructible<allocator_type>::value);                         // constexpr since C++20
+    basic_string(const basic_string& str, size_type pos,
+                 const allocator_type& a = allocator_type());                                   // constexpr since C++20
+    basic_string(const basic_string& str, size_type pos, size_type n,
+                 const Allocator& a = Allocator());                                             // constexpr since C++20
+    constexpr basic_string(
+        basic_string&& str, size_type pos, const Allocator& a = Allocator());                   // since C++23
+    constexpr basic_string(
+        basic_string&& str, size_type pos, size_type n, const Allocator& a = Allocator());      // since C++23
+    template<class T>
+        basic_string(const T& t, size_type pos, size_type n, const Allocator& a = Allocator()); // C++17, constexpr since C++20
+    template <class T>
+        explicit basic_string(const T& t, const Allocator& a = Allocator());                    // C++17, constexpr since C++20
+    basic_string(const value_type* s, const allocator_type& a = allocator_type());              // constexpr since C++20
+    basic_string(const value_type* s, size_type n, const allocator_type& a = allocator_type()); // constexpr since C++20
+    basic_string(nullptr_t) = delete; // C++23
+    basic_string(size_type n, value_type c, const allocator_type& a = allocator_type());        // constexpr since C++20
+    template<class InputIterator>
+        basic_string(InputIterator begin, InputIterator end,
+                     const allocator_type& a = allocator_type());                               // constexpr since C++20
+    template<container-compatible-range<charT> R>
+      constexpr basic_string(from_range_t, R&& rg, const Allocator& a = Allocator());           // since C++23
+    basic_string(initializer_list<value_type>, const Allocator& = Allocator());                 // constexpr since C++20
+    basic_string(const basic_string&, const Allocator&);                                        // constexpr since C++20
+    basic_string(basic_string&&, const Allocator&);                                             // constexpr since C++20
+
+    ~basic_string();                                                                            // constexpr since C++20
+
+    operator basic_string_view<charT, traits>() const noexcept;                                 // constexpr since C++20
+
+    basic_string& operator=(const basic_string& str);                                           // constexpr since C++20
+    template <class T>
+        basic_string& operator=(const T& t);                                                    // C++17, constexpr since C++20
+    basic_string& operator=(basic_string&& str)
+        noexcept(
+             allocator_type::propagate_on_container_move_assignment::value ||
+             allocator_type::is_always_equal::value );                                          // C++17, constexpr since C++20
+    basic_string& operator=(const value_type* s);                                               // constexpr since C++20
+    basic_string& operator=(nullptr_t) = delete; // C++23
+    basic_string& operator=(value_type c);                                                      // constexpr since C++20
+    basic_string& operator=(initializer_list<value_type>);                                      // constexpr since C++20
+
+    iterator       begin() noexcept;                                                            // constexpr since C++20
+    const_iterator begin() const noexcept;                                                      // constexpr since C++20
+    iterator       end() noexcept;                                                              // constexpr since C++20
+    const_iterator end() const noexcept;                                                        // constexpr since C++20
+
+    reverse_iterator       rbegin() noexcept;                                                   // constexpr since C++20
+    const_reverse_iterator rbegin() const noexcept;                                             // constexpr since C++20
+    reverse_iterator       rend() noexcept;                                                     // constexpr since C++20
+    const_reverse_iterator rend() const noexcept;                                               // constexpr since C++20
+
+    const_iterator         cbegin() const noexcept;                                             // constexpr since C++20
+    const_iterator         cend() const noexcept;                                               // constexpr since C++20
+    const_reverse_iterator crbegin() const noexcept;                                            // constexpr since C++20
+    const_reverse_iterator crend() const noexcept;                                              // constexpr since C++20
+
+    size_type size() const noexcept;                                                            // constexpr since C++20
+    size_type length() const noexcept;                                                          // constexpr since C++20
+    size_type max_size() const noexcept;                                                        // constexpr since C++20
+    size_type capacity() const noexcept;                                                        // constexpr since C++20
+
+    void resize(size_type n, value_type c);                                                     // constexpr since C++20
+    void resize(size_type n);                                                                   // constexpr since C++20
+
+    template<class Operation>
+    constexpr void resize_and_overwrite(size_type n, Operation op); // since C++23
+
+    void reserve(size_type res_arg);                                                            // constexpr since C++20
+    void reserve(); // deprecated in C++20
+    void shrink_to_fit();                                                                       // constexpr since C++20
+    void clear() noexcept;                                                                      // constexpr since C++20
+    bool empty() const noexcept;                                                                // constexpr since C++20
+
+    const_reference operator[](size_type pos) const;                                            // constexpr since C++20
+    reference       operator[](size_type pos);                                                  // constexpr since C++20
+
+    const_reference at(size_type n) const;                                                      // constexpr since C++20
+    reference       at(size_type n);                                                            // constexpr since C++20
+
+    basic_string& operator+=(const basic_string& str);                                          // constexpr since C++20
+    template <class T>
+        basic_string& operator+=(const T& t);                                                   // C++17, constexpr since C++20
+    basic_string& operator+=(const value_type* s);                                              // constexpr since C++20
+    basic_string& operator+=(value_type c);                                                     // constexpr since C++20
+    basic_string& operator+=(initializer_list<value_type>);                                     // constexpr since C++20
+
+    basic_string& append(const basic_string& str);                                              // constexpr since C++20
+    template <class T>
+        basic_string& append(const T& t);                                                       // C++17, constexpr since C++20
+    basic_string& append(const basic_string& str, size_type pos, size_type n=npos);             // C++14, constexpr since C++20
+    template <class T>
+        basic_string& append(const T& t, size_type pos, size_type n=npos);                      // C++17, constexpr since C++20
+    basic_string& append(const value_type* s, size_type n);                                     // constexpr since C++20
+    basic_string& append(const value_type* s);                                                  // constexpr since C++20
+    basic_string& append(size_type n, value_type c);                                            // constexpr since C++20
+    template<class InputIterator>
+        basic_string& append(InputIterator first, InputIterator last);                          // constexpr since C++20
+    template<container-compatible-range<charT> R>
+      constexpr basic_string& append_range(R&& rg);                                             // C++23
+    basic_string& append(initializer_list<value_type>);                                         // constexpr since C++20
+
+    void push_back(value_type c);                                                               // constexpr since C++20
+    void pop_back();                                                                            // constexpr since C++20
+    reference       front();                                                                    // constexpr since C++20
+    const_reference front() const;                                                              // constexpr since C++20
+    reference       back();                                                                     // constexpr since C++20
+    const_reference back() const;                                                               // constexpr since C++20
+
+    basic_string& assign(const basic_string& str);                                              // constexpr since C++20
+    template <class T>
+        basic_string& assign(const T& t);                                                       // C++17, constexpr since C++20
+    basic_string& assign(basic_string&& str);                                                   // constexpr since C++20
+    basic_string& assign(const basic_string& str, size_type pos, size_type n=npos);             // C++14, constexpr since C++20
+    template <class T>
+        basic_string& assign(const T& t, size_type pos, size_type n=npos);                      // C++17, constexpr since C++20
+    basic_string& assign(const value_type* s, size_type n);                                     // constexpr since C++20
+    basic_string& assign(const value_type* s);                                                  // constexpr since C++20
+    basic_string& assign(size_type n, value_type c);                                            // constexpr since C++20
+    template<class InputIterator>
+        basic_string& assign(InputIterator first, InputIterator last);                          // constexpr since C++20
+    template<container-compatible-range<charT> R>
+      constexpr basic_string& assign_range(R&& rg);                                             // C++23
+    basic_string& assign(initializer_list<value_type>);                                         // constexpr since C++20
+
+    basic_string& insert(size_type pos1, const basic_string& str);                              // constexpr since C++20
+    template <class T>
+        basic_string& insert(size_type pos1, const T& t);                                       // constexpr since C++20
+    basic_string& insert(size_type pos1, const basic_string& str,
+                         size_type pos2, size_type n);                                          // constexpr since C++20
+    template <class T>
+        basic_string& insert(size_type pos1, const T& t, size_type pos2, size_type n);          // C++17, constexpr since C++20
+    basic_string& insert(size_type pos, const value_type* s, size_type n=npos);                 // C++14, constexpr since C++20
+    basic_string& insert(size_type pos, const value_type* s);                                   // constexpr since C++20
+    basic_string& insert(size_type pos, size_type n, value_type c);                             // constexpr since C++20
+    iterator      insert(const_iterator p, value_type c);                                       // constexpr since C++20
+    iterator      insert(const_iterator p, size_type n, value_type c);                          // constexpr since C++20
+    template<class InputIterator>
+        iterator insert(const_iterator p, InputIterator first, InputIterator last);             // constexpr since C++20
+    template<container-compatible-range<charT> R>
+      constexpr iterator insert_range(const_iterator p, R&& rg);                                // C++23
+    iterator      insert(const_iterator p, initializer_list<value_type>);                       // constexpr since C++20
+
+    basic_string& erase(size_type pos = 0, size_type n = npos);                                 // constexpr since C++20
+    iterator      erase(const_iterator position);                                               // constexpr since C++20
+    iterator      erase(const_iterator first, const_iterator last);                             // constexpr since C++20
+
+    basic_string& replace(size_type pos1, size_type n1, const basic_string& str);               // constexpr since C++20
+    template <class T>
+    basic_string& replace(size_type pos1, size_type n1, const T& t);                            // C++17, constexpr since C++20
+    basic_string& replace(size_type pos1, size_type n1, const basic_string& str,
+                          size_type pos2, size_type n2=npos);                                   // C++14, constexpr since C++20
+    template <class T>
+        basic_string& replace(size_type pos1, size_type n1, const T& t,
+                              size_type pos2, size_type n);                                     // C++17, constexpr since C++20
+    basic_string& replace(size_type pos, size_type n1, const value_type* s, size_type n2);      // constexpr since C++20
+    basic_string& replace(size_type pos, size_type n1, const value_type* s);                    // constexpr since C++20
+    basic_string& replace(size_type pos, size_type n1, size_type n2, value_type c);             // constexpr since C++20
+    basic_string& replace(const_iterator i1, const_iterator i2, const basic_string& str);       // constexpr since C++20
+    template <class T>
+        basic_string& replace(const_iterator i1, const_iterator i2, const T& t);                // C++17, constexpr since C++20
+    basic_string& replace(const_iterator i1, const_iterator i2, const value_type* s, size_type n); // constexpr since C++20
+    basic_string& replace(const_iterator i1, const_iterator i2, const value_type* s);           // constexpr since C++20
+    basic_string& replace(const_iterator i1, const_iterator i2, size_type n, value_type c);     // constexpr since C++20
+    template<class InputIterator>
+        basic_string& replace(const_iterator i1, const_iterator i2, InputIterator j1, InputIterator j2); // constexpr since C++20
+    template<container-compatible-range<charT> R>
+      constexpr basic_string& replace_with_range(const_iterator i1, const_iterator i2, R&& rg); // C++23
+    basic_string& replace(const_iterator i1, const_iterator i2, initializer_list<value_type>);  // constexpr since C++20
+
+    size_type copy(value_type* s, size_type n, size_type pos = 0) const;                        // constexpr since C++20
+    basic_string substr(size_type pos = 0, size_type n = npos) const;                           // constexpr in C++20, removed in C++23
+    basic_string substr(size_type pos = 0, size_type n = npos) const&;                          // since C++23
+    constexpr basic_string substr(size_type pos = 0, size_type n = npos) &&;                    // since C++23
+    void swap(basic_string& str)
+        noexcept(allocator_traits<allocator_type>::propagate_on_container_swap::value ||
+                 allocator_traits<allocator_type>::is_always_equal::value);                     // C++17, constexpr since C++20
+
+    const value_type* c_str() const noexcept;                                                   // constexpr since C++20
+    const value_type* data() const noexcept;                                                    // constexpr since C++20
+          value_type* data()       noexcept;                                                    // C++17, constexpr since C++20
+
+    allocator_type get_allocator() const noexcept;                                              // constexpr since C++20
+
+    size_type find(const basic_string& str, size_type pos = 0) const noexcept;                  // constexpr since C++20
+    template <class T>
+        size_type find(const T& t, size_type pos = 0) const noexcept;                           // C++17, noexcept as an extension, constexpr since C++20
+    size_type find(const value_type* s, size_type pos, size_type n) const noexcept;             // constexpr since C++20
+    size_type find(const value_type* s, size_type pos = 0) const noexcept;                      // constexpr since C++20
+    size_type find(value_type c, size_type pos = 0) const noexcept;                             // constexpr since C++20
+
+    size_type rfind(const basic_string& str, size_type pos = npos) const noexcept;              // constexpr since C++20
+    template <class T>
+        size_type rfind(const T& t, size_type pos = npos) const noexcept;                       // C++17, noexcept as an extension, constexpr since C++20
+    size_type rfind(const value_type* s, size_type pos, size_type n) const noexcept;            // constexpr since C++20
+    size_type rfind(const value_type* s, size_type pos = npos) const noexcept;                  // constexpr since C++20
+    size_type rfind(value_type c, size_type pos = npos) const noexcept;                         // constexpr since C++20
+
+    size_type find_first_of(const basic_string& str, size_type pos = 0) const noexcept;         // constexpr since C++20
+    template <class T>
+        size_type find_first_of(const T& t, size_type pos = 0) const noexcept;                  // C++17, noexcept as an extension, constexpr since C++20
+    size_type find_first_of(const value_type* s, size_type pos, size_type n) const noexcept;    // constexpr since C++20
+    size_type find_first_of(const value_type* s, size_type pos = 0) const noexcept;             // constexpr since C++20
+    size_type find_first_of(value_type c, size_type pos = 0) const noexcept;                    // constexpr since C++20
+
+    size_type find_last_of(const basic_string& str, size_type pos = npos) const noexcept;       // constexpr since C++20
+    template <class T>
+        size_type find_last_of(const T& t, size_type pos = npos) const noexcept noexcept;       // C++17, noexcept as an extension, constexpr since C++20
+    size_type find_last_of(const value_type* s, size_type pos, size_type n) const noexcept;     // constexpr since C++20
+    size_type find_last_of(const value_type* s, size_type pos = npos) const noexcept;           // constexpr since C++20
+    size_type find_last_of(value_type c, size_type pos = npos) const noexcept;                  // constexpr since C++20
+
+    size_type find_first_not_of(const basic_string& str, size_type pos = 0) const noexcept;     // constexpr since C++20
+    template <class T>
+        size_type find_first_not_of(const T& t, size_type pos = 0) const noexcept;              // C++17, noexcept as an extension, constexpr since C++20
+    size_type find_first_not_of(const value_type* s, size_type pos, size_type n) const noexcept; // constexpr since C++20
+    size_type find_first_not_of(const value_type* s, size_type pos = 0) const noexcept;         // constexpr since C++20
+    size_type find_first_not_of(value_type c, size_type pos = 0) const noexcept;                // constexpr since C++20
+
+    size_type find_last_not_of(const basic_string& str, size_type pos = npos) const noexcept;   // constexpr since C++20
+    template <class T>
+        size_type find_last_not_of(const T& t, size_type pos = npos) const noexcept;            // C++17, noexcept as an extension, constexpr since C++20
+    size_type find_last_not_of(const value_type* s, size_type pos, size_type n) const noexcept; // constexpr since C++20
+    size_type find_last_not_of(const value_type* s, size_type pos = npos) const noexcept;       // constexpr since C++20
+    size_type find_last_not_of(value_type c, size_type pos = npos) const noexcept;              // constexpr since C++20
+
+    int compare(const basic_string& str) const noexcept;                                        // constexpr since C++20
+    template <class T>
+        int compare(const T& t) const noexcept;                                                 // C++17, noexcept as an extension, constexpr since C++20
+    int compare(size_type pos1, size_type n1, const basic_string& str) const;                   // constexpr since C++20
+    template <class T>
+        int compare(size_type pos1, size_type n1, const T& t) const;                            // C++17, constexpr since C++20
+    int compare(size_type pos1, size_type n1, const basic_string& str,
+                size_type pos2, size_type n2=npos) const;                                       // C++14, constexpr since C++20
+    template <class T>
+        int compare(size_type pos1, size_type n1, const T& t,
+                    size_type pos2, size_type n2=npos) const;                                   // C++17, constexpr since C++20
+    int compare(const value_type* s) const noexcept;                                            // constexpr since C++20
+    int compare(size_type pos1, size_type n1, const value_type* s) const;                       // constexpr since C++20
+    int compare(size_type pos1, size_type n1, const value_type* s, size_type n2) const;         // constexpr since C++20
+
+    constexpr bool starts_with(basic_string_view<charT, traits> sv) const noexcept;             // C++20
+    constexpr bool starts_with(charT c) const noexcept;                                         // C++20
+    constexpr bool starts_with(const charT* s) const;                                           // C++20
+    constexpr bool ends_with(basic_string_view<charT, traits> sv) const noexcept;               // C++20
+    constexpr bool ends_with(charT c) const noexcept;                                           // C++20
+    constexpr bool ends_with(const charT* s) const;                                             // C++20
+
+    constexpr bool contains(basic_string_view<charT, traits> sv) const noexcept;                // C++23
+    constexpr bool contains(charT c) const noexcept;                                            // C++23
+    constexpr bool contains(const charT* s) const;                                              // C++23
+};
+
+template<class InputIterator,
+         class Allocator = allocator<typename iterator_traits<InputIterator>::value_type>>
+basic_string(InputIterator, InputIterator, Allocator = Allocator())
+   -> basic_string<typename iterator_traits<InputIterator>::value_type,
+                  char_traits<typename iterator_traits<InputIterator>::value_type>,
+                  Allocator>;   // C++17
+
+template<ranges::input_range R,
+         class Allocator = allocator<ranges::range_value_t<R>>>
+  basic_string(from_range_t, R&&, Allocator = Allocator())
+    -> basic_string<ranges::range_value_t<R>, char_traits<ranges::range_value_t<R>>,
+                    Allocator>; // C++23
+
+template<class charT,
+         class traits,
+         class Allocator = allocator<charT>>
+  explicit basic_string(basic_string_view<charT, traits>, const Allocator& = Allocator())
+    -> basic_string<charT, traits, Allocator>; // C++17
+
+template<class charT,
+         class traits,
+         class Allocator = allocator<charT>>
+  basic_string(basic_string_view<charT, traits>,
+                typename see below::size_type, typename see below::size_type,
+                const Allocator& = Allocator())
+    -> basic_string<charT, traits, Allocator>; // C++17
+
+template<class charT, class traits, class Allocator>
+basic_string<charT, traits, Allocator>
+operator+(const basic_string<charT, traits, Allocator>& lhs,
+          const basic_string<charT, traits, Allocator>& rhs);                                   // constexpr since C++20
+
+template<class charT, class traits, class Allocator>
+basic_string<charT, traits, Allocator>
+operator+(const charT* lhs , const basic_string<charT,traits,Allocator>&rhs);                   // constexpr since C++20
+
+template<class charT, class traits, class Allocator>
+basic_string<charT, traits, Allocator>
+operator+(charT lhs, const basic_string<charT,traits,Allocator>& rhs);                          // constexpr since C++20
+
+template<class charT, class traits, class Allocator>
+basic_string<charT, traits, Allocator>
+operator+(const basic_string<charT, traits, Allocator>& lhs, const charT* rhs);                 // constexpr since C++20
+
+template<class charT, class traits, class Allocator>
+basic_string<charT, traits, Allocator>
+operator+(const basic_string<charT, traits, Allocator>& lhs, charT rhs);                        // constexpr since C++20
+
+template<class charT, class traits, class Allocator>
+bool operator==(const basic_string<charT, traits, Allocator>& lhs,
+                const basic_string<charT, traits, Allocator>& rhs) noexcept;                    // constexpr since C++20
+
+template<class charT, class traits, class Allocator>
+bool operator==(const charT* lhs, const basic_string<charT, traits, Allocator>& rhs) noexcept;  // removed in C++20
+
+template<class charT, class traits, class Allocator>
+bool operator==(const basic_string<charT,traits,Allocator>& lhs, const charT* rhs) noexcept;    // constexpr since C++20
+
+template<class charT, class traits, class Allocator>
+bool operator!=(const basic_string<charT,traits,Allocator>& lhs,
+                const basic_string<charT, traits, Allocator>& rhs) noexcept;                    // removed in C++20
+
+template<class charT, class traits, class Allocator>
+bool operator!=(const charT* lhs, const basic_string<charT, traits, Allocator>& rhs) noexcept;  // removed in C++20
+
+template<class charT, class traits, class Allocator>
+bool operator!=(const basic_string<charT, traits, Allocator>& lhs, const charT* rhs) noexcept;  // removed in C++20
+
+template<class charT, class traits, class Allocator>
+bool operator< (const basic_string<charT, traits, Allocator>& lhs,
+                const basic_string<charT, traits, Allocator>& rhs) noexcept;                    // removed in C++20
+
+template<class charT, class traits, class Allocator>
+bool operator< (const basic_string<charT, traits, Allocator>& lhs, const charT* rhs) noexcept;  // removed in C++20
+
+template<class charT, class traits, class Allocator>
+bool operator< (const charT* lhs, const basic_string<charT, traits, Allocator>& rhs) noexcept;  // removed in C++20
+
+template<class charT, class traits, class Allocator>
+bool operator> (const basic_string<charT, traits, Allocator>& lhs,
+                const basic_string<charT, traits, Allocator>& rhs) noexcept;                    // removed in C++20
+
+template<class charT, class traits, class Allocator>
+bool operator> (const basic_string<charT, traits, Allocator>& lhs, const charT* rhs) noexcept;  // removed in C++20
+
+template<class charT, class traits, class Allocator>
+bool operator> (const charT* lhs, const basic_string<charT, traits, Allocator>& rhs) noexcept;  // removed in C++20
+
+template<class charT, class traits, class Allocator>
+bool operator<=(const basic_string<charT, traits, Allocator>& lhs,
+                const basic_string<charT, traits, Allocator>& rhs) noexcept;                    // removed in C++20
+
+template<class charT, class traits, class Allocator>
+bool operator<=(const basic_string<charT, traits, Allocator>& lhs, const charT* rhs) noexcept;  // removed in C++20
+
+template<class charT, class traits, class Allocator>
+bool operator<=(const charT* lhs, const basic_string<charT, traits, Allocator>& rhs) noexcept;  // removed in C++20
+
+template<class charT, class traits, class Allocator>
+bool operator>=(const basic_string<charT, traits, Allocator>& lhs,
+                const basic_string<charT, traits, Allocator>& rhs) noexcept;                    // removed in C++20
+
+template<class charT, class traits, class Allocator>
+bool operator>=(const basic_string<charT, traits, Allocator>& lhs, const charT* rhs) noexcept;  // removed in C++20
+
+template<class charT, class traits, class Allocator>
+bool operator>=(const charT* lhs, const basic_string<charT, traits, Allocator>& rhs) noexcept;  // removed in C++20
+
+template<class charT, class traits, class Allocator>                                            // since C++20
+constexpr see below operator<=>(const basic_string<charT, traits, Allocator>& lhs,
+                                const basic_string<charT, traits, Allocator>& rhs) noexcept;
+
+template<class charT, class traits, class Allocator>                                            // since C++20
+constexpr see below operator<=>(const basic_string<charT, traits, Allocator>& lhs,
+                                const charT* rhs) noexcept;
+
+template<class charT, class traits, class Allocator>
+void swap(basic_string<charT, traits, Allocator>& lhs,
+          basic_string<charT, traits, Allocator>& rhs)
+            noexcept(noexcept(lhs.swap(rhs)));                                                  // constexpr since C++20
+
+template<class charT, class traits, class Allocator>
+basic_istream<charT, traits>&
+operator>>(basic_istream<charT, traits>& is, basic_string<charT, traits, Allocator>& str);
+
+template<class charT, class traits, class Allocator>
+basic_ostream<charT, traits>&
+operator<<(basic_ostream<charT, traits>& os, const basic_string<charT, traits, Allocator>& str);
+
+template<class charT, class traits, class Allocator>
+basic_istream<charT, traits>&
+getline(basic_istream<charT, traits>& is, basic_string<charT, traits, Allocator>& str,
+        charT delim);
+
+template<class charT, class traits, class Allocator>
+basic_istream<charT, traits>&
+getline(basic_istream<charT, traits>& is, basic_string<charT, traits, Allocator>& str);
+
+template<class charT, class traits, class Allocator, class U>
+typename basic_string<charT, traits, Allocator>::size_type
+erase(basic_string<charT, traits, Allocator>& c, const U& value);    // C++20
+template<class charT, class traits, class Allocator, class Predicate>
+typename basic_string<charT, traits, Allocator>::size_type
+erase_if(basic_string<charT, traits, Allocator>& c, Predicate pred); // C++20
+
+typedef basic_string<char>    string;
+typedef basic_string<wchar_t> wstring;
+typedef basic_string<char8_t> u8string; // C++20
+typedef basic_string<char16_t> u16string;
+typedef basic_string<char32_t> u32string;
+
+int                stoi  (const string& str, size_t* idx = nullptr, int base = 10);
+long               stol  (const string& str, size_t* idx = nullptr, int base = 10);
+unsigned long      stoul (const string& str, size_t* idx = nullptr, int base = 10);
+long long          stoll (const string& str, size_t* idx = nullptr, int base = 10);
+unsigned long long stoull(const string& str, size_t* idx = nullptr, int base = 10);
+
+float       stof (const string& str, size_t* idx = nullptr);
+double      stod (const string& str, size_t* idx = nullptr);
+long double stold(const string& str, size_t* idx = nullptr);
+
+string to_string(int val);
+string to_string(unsigned val);
+string to_string(long val);
+string to_string(unsigned long val);
+string to_string(long long val);
+string to_string(unsigned long long val);
+string to_string(float val);
+string to_string(double val);
+string to_string(long double val);
+
+int                stoi  (const wstring& str, size_t* idx = nullptr, int base = 10);
+long               stol  (const wstring& str, size_t* idx = nullptr, int base = 10);
+unsigned long      stoul (const wstring& str, size_t* idx = nullptr, int base = 10);
+long long          stoll (const wstring& str, size_t* idx = nullptr, int base = 10);
+unsigned long long stoull(const wstring& str, size_t* idx = nullptr, int base = 10);
+
+float       stof (const wstring& str, size_t* idx = nullptr);
+double      stod (const wstring& str, size_t* idx = nullptr);
+long double stold(const wstring& str, size_t* idx = nullptr);
+
+wstring to_wstring(int val);
+wstring to_wstring(unsigned val);
+wstring to_wstring(long val);
+wstring to_wstring(unsigned long val);
+wstring to_wstring(long long val);
+wstring to_wstring(unsigned long long val);
+wstring to_wstring(float val);
+wstring to_wstring(double val);
+wstring to_wstring(long double val);
+
+template <> struct hash<string>;
+template <> struct hash<u8string>; // C++20
+template <> struct hash<u16string>;
+template <> struct hash<u32string>;
+template <> struct hash<wstring>;
+
+basic_string<char>     operator""s( const char *str,     size_t len );           // C++14, constexpr since C++20
+basic_string<wchar_t>  operator""s( const wchar_t *str,  size_t len );           // C++14, constexpr since C++20
+constexpr basic_string<char8_t>  operator""s( const char8_t *str,  size_t len ); // C++20
+basic_string<char16_t> operator""s( const char16_t *str, size_t len );           // C++14, constexpr since C++20
+basic_string<char32_t> operator""s( const char32_t *str, size_t len );           // C++14, constexpr since C++20
+
+}  // std
+
+*/
+
+#include <__algorithm/max.h>
+#include <__algorithm/min.h>
+#include <__algorithm/remove.h>
+#include <__algorithm/remove_if.h>
+#include <__assert> // all public C++ headers provide the assertion handler
+#include <__config>
+#include <__format/enable_insertable.h>
+#include <__functional/hash.h>
+#include <__functional/unary_function.h>
+#include <__fwd/string.h>
+#include <__ios/fpos.h>
+#include <__iterator/distance.h>
+#include <__iterator/iterator_traits.h>
+#include <__iterator/reverse_iterator.h>
+#include <__iterator/wrap_iter.h>
+#include <__memory/addressof.h>
+#include <__memory/allocate_at_least.h>
+#include <__memory/allocator.h>
+#include <__memory/allocator_traits.h>
+#include <__memory/compressed_pair.h>
+#include <__memory/construct_at.h>
+#include <__memory/pointer_traits.h>
+#include <__memory/swap_allocator.h>
+#include <__memory_resource/polymorphic_allocator.h>
+#include <__ranges/access.h>
+#include <__ranges/concepts.h>
+#include <__ranges/container_compatible_range.h>
+#include <__ranges/from_range.h>
+#include <__ranges/size.h>
+#include <__string/char_traits.h>
+#include <__string/extern_template_lists.h>
+#include <__type_traits/is_allocator.h>
+#include <__type_traits/is_array.h>
+#include <__type_traits/is_convertible.h>
+#include <__type_traits/is_nothrow_default_constructible.h>
+#include <__type_traits/is_nothrow_move_assignable.h>
+#include <__type_traits/is_same.h>
+#include <__type_traits/is_standard_layout.h>
+#include <__type_traits/is_trivial.h>
+#include <__type_traits/noexcept_move_assign_container.h>
+#include <__type_traits/remove_cvref.h>
+#include <__type_traits/void_t.h>
+#include <__utility/auto_cast.h>
+#include <__utility/declval.h>
+#include <__utility/forward.h>
+#include <__utility/is_pointer_in_range.h>
+#include <__utility/move.h>
+#include <__utility/swap.h>
+#include <__utility/unreachable.h>
+#include <climits>
+#include <cstdint>
+#include <cstdio>  // EOF
+#include <cstring>
+#include <limits>
+#include <stdexcept>
+#include <string_view>
+#include <version>
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+#  include <cwchar>
+#endif
+
+// standard-mandated includes
+
+// [iterator.range]
+#include <__iterator/access.h>
+#include <__iterator/data.h>
+#include <__iterator/empty.h>
+#include <__iterator/reverse_access.h>
+#include <__iterator/size.h>
+
+// [string.syn]
+#include <compare>
+#include <initializer_list>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+// basic_string
+
+template<class _CharT, class _Traits, class _Allocator>
+basic_string<_CharT, _Traits, _Allocator>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+operator+(const basic_string<_CharT, _Traits, _Allocator>& __x,
+          const basic_string<_CharT, _Traits, _Allocator>& __y);
+
+template<class _CharT, class _Traits, class _Allocator>
+_LIBCPP_HIDDEN _LIBCPP_CONSTEXPR_SINCE_CXX20
+basic_string<_CharT, _Traits, _Allocator>
+operator+(const _CharT* __x, const basic_string<_CharT,_Traits,_Allocator>& __y);
+
+template<class _CharT, class _Traits, class _Allocator>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+basic_string<_CharT, _Traits, _Allocator>
+operator+(_CharT __x, const basic_string<_CharT,_Traits,_Allocator>& __y);
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+basic_string<_CharT, _Traits, _Allocator>
+operator+(const basic_string<_CharT, _Traits, _Allocator>& __x, const _CharT* __y);
+
+template<class _CharT, class _Traits, class _Allocator>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+basic_string<_CharT, _Traits, _Allocator>
+operator+(const basic_string<_CharT, _Traits, _Allocator>& __x, _CharT __y);
+
+extern template _LIBCPP_EXPORTED_FROM_ABI string operator+
+    <char, char_traits<char>, allocator<char> >(char const*, string const&);
+
+template <class _Iter>
+struct __string_is_trivial_iterator : public false_type {};
+
+template <class _Tp>
+struct __string_is_trivial_iterator<_Tp*>
+    : public is_arithmetic<_Tp> {};
+
+template <class _Iter>
+struct __string_is_trivial_iterator<__wrap_iter<_Iter> >
+    : public __string_is_trivial_iterator<_Iter> {};
+
+template <class _CharT, class _Traits, class _Tp>
+struct __can_be_converted_to_string_view : public _BoolConstant<
+      is_convertible<const _Tp&, basic_string_view<_CharT, _Traits> >::value &&
+     !is_convertible<const _Tp&, const _CharT*>::value
+    > {};
+
+struct __uninitialized_size_tag {};
+struct __init_with_sentinel_tag {};
+
+template<class _CharT, class _Traits, class _Allocator>
+class basic_string
+{
+    static_assert(sizeof(_CharT) <= 4, "libc++ implementation of std::basic_string does not support extra-wide character types");
+public:
+    typedef basic_string                                 __self;
+    typedef basic_string_view<_CharT, _Traits>           __self_view;
+    typedef _Traits                                      traits_type;
+    typedef _CharT                                       value_type;
+    typedef _Allocator                                   allocator_type;
+    typedef allocator_traits<allocator_type>             __alloc_traits;
+    typedef typename __alloc_traits::size_type           size_type;
+    typedef typename __alloc_traits::difference_type     difference_type;
+    typedef value_type&                                  reference;
+    typedef const value_type&                            const_reference;
+    typedef typename __alloc_traits::pointer             pointer;
+    typedef typename __alloc_traits::const_pointer       const_pointer;
+
+    static_assert((!is_array<value_type>::value), "Character type of basic_string must not be an array");
+    static_assert(( is_standard_layout<value_type>::value), "Character type of basic_string must be standard-layout");
+    static_assert(( is_trivial<value_type>::value), "Character type of basic_string must be trivial");
+    static_assert(( is_same<_CharT, typename traits_type::char_type>::value),
+                  "traits_type::char_type must be the same type as CharT");
+    static_assert(( is_same<typename allocator_type::value_type, value_type>::value),
+                  "Allocator::value_type must be same type as value_type");
+
+    static_assert(is_same<allocator_type, __rebind_alloc<__alloc_traits, value_type> >::value,
+                  "[allocator.requirements] states that rebinding an allocator to the same type should result in the "
+                  "original allocator");
+
+#if _YNDX_LIBCPP_MAKE_STRING_ITERATOR_POINTERS == 1
+    typedef pointer                                      iterator;
+    typedef const_pointer                                const_iterator;
+#else
+    // TODO: Implement iterator bounds checking without requiring the global database.
+    typedef __wrap_iter<pointer>                         iterator;
+    typedef __wrap_iter<const_pointer>                   const_iterator;
+#endif
+    typedef std::reverse_iterator<iterator>              reverse_iterator;
+    typedef std::reverse_iterator<const_iterator>        const_reverse_iterator;
+
+private:
+    static_assert(CHAR_BIT == 8, "This implementation assumes that one byte contains 8 bits");
+
+#ifdef _LIBCPP_ABI_ALTERNATE_STRING_LAYOUT
+
+    struct __long
+    {
+        pointer   __data_;
+        size_type __size_;
+        size_type __cap_ : sizeof(size_type) * CHAR_BIT - 1;
+        size_type __is_long_ : 1;
+    };
+
+    enum {__min_cap = (sizeof(__long) - 1)/sizeof(value_type) > 2 ?
+                      (sizeof(__long) - 1)/sizeof(value_type) : 2};
+
+    struct __short
+    {
+        value_type __data_[__min_cap];
+        unsigned char __padding_[sizeof(value_type) - 1];
+        unsigned char __size_ : 7;
+        unsigned char __is_long_ : 1;
+    };
+
+// The __endian_factor is required because the field we use to store the size
+// has one fewer bit than it would if it were not a bitfield.
+//
+// If the LSB is used to store the short-flag in the short string representation,
+// we have to multiply the size by two when it is stored and divide it by two when
+// it is loaded to make sure that we always store an even number. In the long string
+// representation, we can ignore this because we can assume that we always allocate
+// an even amount of value_types.
+//
+// If the MSB is used for the short-flag, the max_size() is numeric_limits<size_type>::max() / 2.
+// This does not impact the short string representation, since we never need the MSB
+// for representing the size of a short string anyway.
+
+#ifdef _LIBCPP_BIG_ENDIAN
+    static const size_type __endian_factor = 2;
+#else
+    static const size_type __endian_factor = 1;
+#endif
+
+#else // _LIBCPP_ABI_ALTERNATE_STRING_LAYOUT
+
+#ifdef _LIBCPP_BIG_ENDIAN
+    static const size_type __endian_factor = 1;
+#else
+    static const size_type __endian_factor = 2;
+#endif
+
+    // Attribute 'packed' is used to keep the layout compatible with the
+    // previous definition that did not use bit fields. This is because on
+    // some platforms bit fields have a default size rather than the actual
+    // size used, e.g., it is 4 bytes on AIX. See D128285 for details.
+    struct __long
+    {
+        struct _LIBCPP_PACKED {
+            size_type __is_long_ : 1;
+            size_type __cap_ : sizeof(size_type) * CHAR_BIT - 1;
+        };
+        size_type __size_;
+        pointer   __data_;
+    };
+
+    enum {__min_cap = (sizeof(__long) - 1)/sizeof(value_type) > 2 ?
+                      (sizeof(__long) - 1)/sizeof(value_type) : 2};
+
+    struct __short
+    {
+        struct _LIBCPP_PACKED {
+            unsigned char __is_long_ : 1;
+            unsigned char __size_ : 7;
+        };
+        char __padding_[sizeof(value_type) - 1];
+        value_type __data_[__min_cap];
+    };
+
+#endif // _LIBCPP_ABI_ALTERNATE_STRING_LAYOUT
+
+    static_assert(sizeof(__short) == (sizeof(value_type) * (__min_cap + 1)), "__short has an unexpected size.");
+
+    union __ulx{__long __lx; __short __lxx;};
+
+    enum {__n_words = sizeof(__ulx) / sizeof(size_type)};
+
+    struct __raw
+    {
+        size_type __words[__n_words];
+    };
+
+    struct __rep
+    {
+        union
+        {
+            __long  __l;
+            __short __s;
+            __raw   __r;
+        };
+    };
+
+    __compressed_pair<__rep, allocator_type> __r_;
+
+    // Construct a string with the given allocator and enough storage to hold `__size` characters, but
+    // don't initialize the characters. The contents of the string, including the null terminator, must be
+    // initialized separately.
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    explicit basic_string(__uninitialized_size_tag, size_type __size, const allocator_type& __a)
+            : __r_(__default_init_tag(), __a) {
+        if (__size > max_size())
+            __throw_length_error();
+        if (__fits_in_sso(__size)) {
+            __r_.first() = __rep();
+            __set_short_size(__size);
+        } else {
+            auto __capacity = __recommend(__size) + 1;
+            auto __allocation = __alloc_traits::allocate(__alloc(), __capacity);
+            __begin_lifetime(__allocation, __capacity);
+            __set_long_cap(__capacity);
+            __set_long_pointer(__allocation);
+            __set_long_size(__size);
+        }
+    }
+
+    template <class _Iter, class _Sent>
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    basic_string(__init_with_sentinel_tag, _Iter __first, _Sent __last, const allocator_type& __a)
+        : __r_(__default_init_tag(), __a) {
+      __init_with_sentinel(std::move(__first), std::move(__last));
+    }
+
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 iterator __make_iterator(pointer __p) {
+        return iterator(__p);
+    }
+
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 const_iterator __make_const_iterator(const_pointer __p) const {
+        return const_iterator(__p);
+    }
+
+public:
+  _LIBCPP_TEMPLATE_DATA_VIS static const size_type npos = -1;
+
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string()
+      _NOEXCEPT_(is_nothrow_default_constructible<allocator_type>::value)
+      : __r_(__default_init_tag(), __default_init_tag()) {
+    __default_init();
+  }
+
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 explicit basic_string(const allocator_type& __a)
+#if _LIBCPP_STD_VER <= 14
+      _NOEXCEPT_(is_nothrow_copy_constructible<allocator_type>::value)
+#else
+      _NOEXCEPT
+#endif
+      : __r_(__default_init_tag(), __a) {
+    __default_init();
+  }
+
+  _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string(const basic_string& __str)
+      : __r_(__default_init_tag(), __alloc_traits::select_on_container_copy_construction(__str.__alloc())) {
+    if (!__str.__is_long())
+      __r_.first() = __str.__r_.first();
+    else
+      __init_copy_ctor_external(std::__to_address(__str.__get_long_pointer()), __str.__get_long_size());
+  }
+
+  _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string(const basic_string& __str, const allocator_type& __a)
+      : __r_(__default_init_tag(), __a) {
+    if (!__str.__is_long())
+      __r_.first() = __str.__r_.first();
+    else
+      __init_copy_ctor_external(std::__to_address(__str.__get_long_pointer()), __str.__get_long_size());
+  }
+
+#ifndef _LIBCPP_CXX03_LANG
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string(basic_string&& __str)
+#  if _LIBCPP_STD_VER <= 14
+      _NOEXCEPT_(is_nothrow_move_constructible<allocator_type>::value)
+#  else
+      _NOEXCEPT
+#  endif
+      : __r_(std::move(__str.__r_)) {
+    __str.__default_init();
+  }
+
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string(basic_string&& __str, const allocator_type& __a)
+      : __r_(__default_init_tag(), __a) {
+    if (__str.__is_long() && __a != __str.__alloc()) // copy, not move
+      __init(std::__to_address(__str.__get_long_pointer()), __str.__get_long_size());
+    else {
+      if (__libcpp_is_constant_evaluated())
+        __r_.first() = __rep();
+      __r_.first() = __str.__r_.first();
+      __str.__default_init();
+    }
+  }
+#endif // _LIBCPP_CXX03_LANG
+
+  template <__enable_if_t<__is_allocator<_Allocator>::value, int> = 0>
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string(const _CharT* __s)
+      : __r_(__default_init_tag(), __default_init_tag()) {
+    _LIBCPP_ASSERT_UNCATEGORIZED(__s != nullptr, "basic_string(const char*) detected nullptr");
+    __init(__s, traits_type::length(__s));
+  }
+
+  template <__enable_if_t<__is_allocator<_Allocator>::value, int> = 0>
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string(const _CharT* __s, const _Allocator& __a)
+      : __r_(__default_init_tag(), __a) {
+    _LIBCPP_ASSERT_UNCATEGORIZED(__s != nullptr, "basic_string(const char*, allocator) detected nullptr");
+    __init(__s, traits_type::length(__s));
+  }
+
+#if _LIBCPP_STD_VER >= 20
+  basic_string(nullptr_t) = delete;
+#endif
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+  basic_string(nullptr_t, size_t) = delete;
+
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string(const _CharT* __s, size_type __n)
+      : __r_(__default_init_tag(), __default_init_tag()) {
+    _LIBCPP_ASSERT_UNCATEGORIZED(__n == 0 || __s != nullptr, "basic_string(const char*, n) detected nullptr");
+    __init(__s, __n);
+  }
+
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+  basic_string(nullptr_t, size_t, const _Allocator&) = delete;
+
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+  basic_string(const _CharT* __s, size_type __n, const _Allocator& __a)
+      : __r_(__default_init_tag(), __a) {
+    _LIBCPP_ASSERT_UNCATEGORIZED(__n == 0 || __s != nullptr,
+                                 "basic_string(const char*, n, allocator) detected nullptr");
+    __init(__s, __n);
+  }
+
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string(size_type __n, _CharT __c)
+      : __r_(__default_init_tag(), __default_init_tag()) {
+    __init(__n, __c);
+  }
+
+#if _LIBCPP_STD_VER >= 23
+  _LIBCPP_HIDE_FROM_ABI constexpr
+  basic_string(basic_string&& __str, size_type __pos, const _Allocator& __alloc = _Allocator())
+      : basic_string(std::move(__str), __pos, npos, __alloc) {}
+
+  _LIBCPP_HIDE_FROM_ABI constexpr
+  basic_string(basic_string&& __str, size_type __pos, size_type __n, const _Allocator& __alloc = _Allocator())
+      : __r_(__default_init_tag(), __alloc) {
+    if (__pos > __str.size())
+      __throw_out_of_range();
+
+    auto __len = std::min<size_type>(__n, __str.size() - __pos);
+    if (__alloc_traits::is_always_equal::value || __alloc == __str.__alloc()) {
+      __r_.first() = __str.__r_.first();
+      __str.__default_init();
+
+      _Traits::move(data(), data() + __pos, __len);
+      __set_size(__len);
+      _Traits::assign(data()[__len], value_type());
+    } else {
+      // Perform a copy because the allocators are not compatible.
+      __init(__str.data() + __pos, __len);
+    }
+  }
+#endif
+
+  template <__enable_if_t<__is_allocator<_Allocator>::value, int> = 0>
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string(size_type __n, _CharT __c, const _Allocator& __a)
+      : __r_(__default_init_tag(), __a) {
+    __init(__n, __c);
+  }
+
+  _LIBCPP_CONSTEXPR_SINCE_CXX20
+  basic_string(const basic_string& __str, size_type __pos, size_type __n, const _Allocator& __a = _Allocator())
+      : __r_(__default_init_tag(), __a) {
+    size_type __str_sz = __str.size();
+    if (__pos > __str_sz)
+      __throw_out_of_range();
+    __init(__str.data() + __pos, std::min(__n, __str_sz - __pos));
+  }
+
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+  basic_string(const basic_string& __str, size_type __pos, const _Allocator& __a = _Allocator())
+      : __r_(__default_init_tag(), __a) {
+    size_type __str_sz = __str.size();
+    if (__pos > __str_sz)
+      __throw_out_of_range();
+    __init(__str.data() + __pos, __str_sz - __pos);
+  }
+
+  template <class _Tp,
+            __enable_if_t<__can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value &&
+                              !__is_same_uncvref<_Tp, basic_string>::value,
+                          int> = 0>
+  _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_SINCE_CXX20
+  basic_string(const _Tp& __t, size_type __pos, size_type __n, const allocator_type& __a = allocator_type())
+      : __r_(__default_init_tag(), __a) {
+    __self_view __sv0 = __t;
+    __self_view __sv  = __sv0.substr(__pos, __n);
+    __init(__sv.data(), __sv.size());
+  }
+
+  template <class _Tp,
+            __enable_if_t<__can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value &&
+                              !__is_same_uncvref<_Tp, basic_string>::value,
+                          int> = 0>
+  _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_SINCE_CXX20 explicit basic_string(const _Tp& __t)
+      : __r_(__default_init_tag(), __default_init_tag()) {
+    __self_view __sv = __t;
+    __init(__sv.data(), __sv.size());
+  }
+
+  template <class _Tp,
+            __enable_if_t<__can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value &&
+                              !__is_same_uncvref<_Tp, basic_string>::value,
+                          int> = 0>
+  _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_SINCE_CXX20 explicit basic_string(
+      const _Tp& __t, const allocator_type& __a)
+      : __r_(__default_init_tag(), __a) {
+    __self_view __sv = __t;
+    __init(__sv.data(), __sv.size());
+  }
+
+  template <class _InputIterator, __enable_if_t<__has_input_iterator_category<_InputIterator>::value, int> = 0>
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string(_InputIterator __first, _InputIterator __last)
+      : __r_(__default_init_tag(), __default_init_tag()) {
+    __init(__first, __last);
+  }
+
+  template <class _InputIterator, __enable_if_t<__has_input_iterator_category<_InputIterator>::value, int> = 0>
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+  basic_string(_InputIterator __first, _InputIterator __last, const allocator_type& __a)
+      : __r_(__default_init_tag(), __a) {
+    __init(__first, __last);
+  }
+
+#if _LIBCPP_STD_VER >= 23
+  template <_ContainerCompatibleRange<_CharT> _Range>
+  _LIBCPP_HIDE_FROM_ABI constexpr
+  basic_string(from_range_t, _Range&& __range, const allocator_type& __a = allocator_type())
+      : __r_(__default_init_tag(), __a) {
+    if constexpr (ranges::forward_range<_Range> || ranges::sized_range<_Range>) {
+      __init_with_size(ranges::begin(__range), ranges::end(__range), ranges::distance(__range));
+    } else {
+      __init_with_sentinel(ranges::begin(__range), ranges::end(__range));
+    }
+  }
+#endif
+
+#ifndef _LIBCPP_CXX03_LANG
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string(initializer_list<_CharT> __il)
+      : __r_(__default_init_tag(), __default_init_tag()) {
+    __init(__il.begin(), __il.end());
+  }
+
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string(initializer_list<_CharT> __il, const _Allocator& __a)
+      : __r_(__default_init_tag(), __a) {
+    __init(__il.begin(), __il.end());
+  }
+#endif // _LIBCPP_CXX03_LANG
+
+  inline _LIBCPP_CONSTEXPR_SINCE_CXX20 ~basic_string() {
+    if (__is_long())
+      __alloc_traits::deallocate(__alloc(), __get_long_pointer(), __get_long_cap());
+  }
+
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    operator __self_view() const _NOEXCEPT { return __self_view(data(), size()); }
+
+    _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string& operator=(const basic_string& __str);
+
+    template <class _Tp, __enable_if_t<__can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value &&
+                                           !__is_same_uncvref<_Tp, basic_string>::value, int> = 0>
+    _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string& operator=(const _Tp& __t) {
+      __self_view __sv = __t;
+      return assign(__sv);
+    }
+
+#ifndef _LIBCPP_CXX03_LANG
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string& operator=(basic_string&& __str)
+      _NOEXCEPT_((__noexcept_move_assign_container<_Allocator, __alloc_traits>::value)) {
+    __move_assign(__str, integral_constant<bool, __alloc_traits::propagate_on_container_move_assignment::value>());
+    return *this;
+  }
+
+     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    basic_string& operator=(initializer_list<value_type> __il) {return assign(__il.begin(), __il.size());}
+#endif
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    basic_string& operator=(const value_type* __s) {return assign(__s);}
+#if _LIBCPP_STD_VER >= 20
+    basic_string& operator=(nullptr_t) = delete;
+#endif
+    _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string& operator=(value_type __c);
+
+#ifndef _YNDX_LIBCPP_MAKE_STRING_ITERATOR_POINTERS == 1
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    iterator begin() _NOEXCEPT
+        {return __make_iterator(__get_pointer());}
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    const_iterator begin() const _NOEXCEPT
+        {return __make_const_iterator(__get_pointer());}
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    iterator end() _NOEXCEPT
+        {return __make_iterator(__get_pointer() + size());}
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    const_iterator end() const _NOEXCEPT
+        {return __make_const_iterator(__get_pointer() + size());}
+#else
+    // It is necessary to keep the list of constructors matching the one above it.
+    // Made to support pointer iterators
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    iterator begin() _NOEXCEPT
+        {return iterator(__get_pointer());}
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    const_iterator begin() const _NOEXCEPT
+        {return const_iterator(__get_pointer());}
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    iterator end() _NOEXCEPT
+        {return iterator(__get_pointer() + size());}
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    const_iterator end() const _NOEXCEPT
+        {return const_iterator(__get_pointer() + size());}
+#endif // _YNDX_LIBCPP_MAKE_STRING_ITERATOR_POINTERS == 1
+
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    reverse_iterator rbegin() _NOEXCEPT
+        {return reverse_iterator(end());}
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    const_reverse_iterator rbegin() const _NOEXCEPT
+        {return const_reverse_iterator(end());}
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    reverse_iterator rend() _NOEXCEPT
+        {return reverse_iterator(begin());}
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    const_reverse_iterator rend() const _NOEXCEPT
+        {return const_reverse_iterator(begin());}
+
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    const_iterator cbegin() const _NOEXCEPT
+        {return begin();}
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    const_iterator cend() const _NOEXCEPT
+        {return end();}
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    const_reverse_iterator crbegin() const _NOEXCEPT
+        {return rbegin();}
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    const_reverse_iterator crend() const _NOEXCEPT
+        {return rend();}
+
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type size() const _NOEXCEPT
+        {return __is_long() ? __get_long_size() : __get_short_size();}
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type length() const _NOEXCEPT {return size();}
+
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type max_size() const _NOEXCEPT {
+    size_type __m = __alloc_traits::max_size(__alloc());
+    if (__m <= std::numeric_limits<size_type>::max() / 2) {
+      return __m - __alignment;
+    } else {
+    bool __uses_lsb = __endian_factor == 2;
+      return __uses_lsb ? __m - __alignment : (__m / 2) - __alignment;
+    }
+  }
+
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type capacity() const _NOEXCEPT {
+        return (__is_long() ? __get_long_cap() : static_cast<size_type>(__min_cap)) - 1;
+    }
+
+#if _YNDX_LIBCXX_ENABLE_STRING_RESIZE_UNINITIALIZED == 1
+    inline void resize_uninitialized(size_type __n)
+    {
+        __resize_default_init(__n);
+    }
+#endif
+
+    _LIBCPP_CONSTEXPR_SINCE_CXX20 void resize(size_type __n, value_type __c);
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void resize(size_type __n) { resize(__n, value_type()); }
+
+    _LIBCPP_CONSTEXPR_SINCE_CXX20 void reserve(size_type __requested_capacity);
+
+#if _LIBCPP_STD_VER >= 23
+    template <class _Op>
+    _LIBCPP_HIDE_FROM_ABI constexpr
+    void resize_and_overwrite(size_type __n, _Op __op) {
+      __resize_default_init(__n);
+      __erase_to_end(std::move(__op)(data(), _LIBCPP_AUTO_CAST(__n)));
+    }
+#endif
+
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void __resize_default_init(size_type __n);
+
+    _LIBCPP_DEPRECATED_IN_CXX20 _LIBCPP_HIDE_FROM_ABI void reserve() _NOEXCEPT { shrink_to_fit(); }
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void shrink_to_fit() _NOEXCEPT;
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void clear() _NOEXCEPT;
+
+    _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    bool empty() const _NOEXCEPT {return size() == 0;}
+
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 const_reference operator[](size_type __pos) const _NOEXCEPT {
+    _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(__pos <= size(), "string index out of bounds");
+    return *(data() + __pos);
+  }
+
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 reference operator[](size_type __pos) _NOEXCEPT {
+    _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(__pos <= size(), "string index out of bounds");
+    return *(__get_pointer() + __pos);
+  }
+
+    _LIBCPP_CONSTEXPR_SINCE_CXX20 const_reference at(size_type __n) const;
+    _LIBCPP_CONSTEXPR_SINCE_CXX20 reference       at(size_type __n);
+
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string& operator+=(const basic_string& __str) {
+        return append(__str);
+    }
+
+    template <class _Tp,
+              __enable_if_t<__can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value &&
+                                !__is_same_uncvref<_Tp, basic_string >::value,
+                            int> = 0>
+    _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string&
+    operator+=(const _Tp& __t) {
+        __self_view __sv = __t; return append(__sv);
+    }
+
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string& operator+=(const value_type* __s) {
+        return append(__s);
+    }
+
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string& operator+=(value_type __c) {
+        push_back(__c);
+        return *this;
+    }
+
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    basic_string& operator+=(initializer_list<value_type> __il) { return append(__il); }
+#endif // _LIBCPP_CXX03_LANG
+
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string& append(const basic_string& __str) {
+        return append(__str.data(), __str.size());
+  }
+
+  template <class _Tp,
+            __enable_if_t<__can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value &&
+                              !__is_same_uncvref<_Tp, basic_string>::value,
+                          int> = 0>
+  _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string&
+  append(const _Tp& __t) {
+        __self_view __sv = __t;
+        return append(__sv.data(), __sv.size());
+  }
+
+    _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string& append(const basic_string& __str, size_type __pos, size_type __n=npos);
+
+    template <class _Tp,
+              __enable_if_t<__can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value &&
+                                !__is_same_uncvref<_Tp, basic_string>::value,
+                            int> = 0>
+    _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_SINCE_CXX20
+
+        basic_string&
+        append(const _Tp& __t, size_type __pos, size_type __n = npos);
+
+    _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string& append(const value_type* __s, size_type __n);
+    _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string& append(const value_type* __s);
+    _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string& append(size_type __n, value_type __c);
+
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    void __append_default_init(size_type __n);
+
+    template <class _InputIterator, __enable_if_t<__has_exactly_input_iterator_category<_InputIterator>::value, int> = 0>
+    _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string&
+    append(_InputIterator __first, _InputIterator __last) {
+        const basic_string __temp(__first, __last, __alloc());
+        append(__temp.data(), __temp.size());
+        return *this;
+    }
+
+    template <class _ForwardIterator, __enable_if_t<__has_forward_iterator_category<_ForwardIterator>::value, int> = 0>
+    _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string&
+    append(_ForwardIterator __first, _ForwardIterator __last);
+
+#if _LIBCPP_STD_VER >= 23
+    template <_ContainerCompatibleRange<_CharT> _Range>
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr basic_string& append_range(_Range&& __range) {
+      insert_range(end(), std::forward<_Range>(__range));
+      return *this;
+    }
+#endif
+
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    basic_string& append(initializer_list<value_type> __il) {return append(__il.begin(), __il.size());}
+#endif // _LIBCPP_CXX03_LANG
+
+    _LIBCPP_CONSTEXPR_SINCE_CXX20 void push_back(value_type __c);
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void pop_back();
+
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 reference front() _NOEXCEPT {
+    _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(!empty(), "string::front(): string is empty");
+    return *__get_pointer();
+  }
+
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 const_reference front() const _NOEXCEPT {
+    _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(!empty(), "string::front(): string is empty");
+    return *data();
+  }
+
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 reference back() _NOEXCEPT {
+    _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(!empty(), "string::back(): string is empty");
+    return *(__get_pointer() + size() - 1);
+  }
+
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 const_reference back() const _NOEXCEPT {
+    _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(!empty(), "string::back(): string is empty");
+    return *(data() + size() - 1);
+  }
+
+  template <class _Tp, __enable_if_t<__can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value, int> = 0>
+  _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string&
+  assign(const _Tp& __t) {
+    __self_view __sv = __t;
+    return assign(__sv.data(), __sv.size());
+  }
+
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    basic_string& assign(const basic_string& __str) { return *this = __str; }
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    basic_string& assign(basic_string&& __str)
+        _NOEXCEPT_((__noexcept_move_assign_container<_Allocator, __alloc_traits>::value))
+        {*this = std::move(__str); return *this;}
+#endif
+    _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string& assign(const basic_string& __str, size_type __pos, size_type __n=npos);
+
+    template <class _Tp,
+              __enable_if_t<__can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value &&
+                                !__is_same_uncvref<_Tp, basic_string>::value,
+                            int> = 0>
+    _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string&
+    assign(const _Tp& __t, size_type __pos, size_type __n = npos);
+
+    _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string& assign(const value_type* __s, size_type __n);
+    _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string& assign(const value_type* __s);
+    _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string& assign(size_type __n, value_type __c);
+    template <class _InputIterator, __enable_if_t<__has_exactly_input_iterator_category<_InputIterator>::value, int> = 0>
+    _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string&
+    assign(_InputIterator __first, _InputIterator __last);
+
+    template <class _ForwardIterator, __enable_if_t<__has_forward_iterator_category<_ForwardIterator>::value, int> = 0>
+    _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string&
+    assign(_ForwardIterator __first, _ForwardIterator __last);
+
+#if _LIBCPP_STD_VER >= 23
+    template <_ContainerCompatibleRange<_CharT> _Range>
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr basic_string& assign_range(_Range&& __range) {
+      if constexpr (__string_is_trivial_iterator<ranges::iterator_t<_Range>>::value &&
+          (ranges::forward_range<_Range> || ranges::sized_range<_Range>)) {
+        size_type __n = static_cast<size_type>(ranges::distance(__range));
+        __assign_trivial(ranges::begin(__range), ranges::end(__range), __n);
+
+      } else {
+        __assign_with_sentinel(ranges::begin(__range), ranges::end(__range));
+      }
+
+      return *this;
+    }
+#endif
+
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    basic_string& assign(initializer_list<value_type> __il) {return assign(__il.begin(), __il.size());}
+#endif // _LIBCPP_CXX03_LANG
+
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string&
+  insert(size_type __pos1, const basic_string& __str) {
+    return insert(__pos1, __str.data(), __str.size());
+  }
+
+  template <class _Tp, __enable_if_t<__can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value, int> = 0>
+  _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string&
+  insert(size_type __pos1, const _Tp& __t) {
+    __self_view __sv = __t;
+    return insert(__pos1, __sv.data(), __sv.size());
+  }
+
+  template <class _Tp,
+            __enable_if_t<__can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value &&
+                              !__is_same_uncvref<_Tp, basic_string>::value,
+                          int> = 0>
+  _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string&
+  insert(size_type __pos1, const _Tp& __t, size_type __pos2, size_type __n = npos);
+
+  _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string&
+  insert(size_type __pos1, const basic_string& __str, size_type __pos2, size_type __n = npos);
+  _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string& insert(size_type __pos, const value_type* __s, size_type __n);
+  _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string& insert(size_type __pos, const value_type* __s);
+  _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string& insert(size_type __pos, size_type __n, value_type __c);
+  _LIBCPP_CONSTEXPR_SINCE_CXX20 iterator insert(const_iterator __pos, value_type __c);
+
+#if _LIBCPP_STD_VER >= 23
+    template <_ContainerCompatibleRange<_CharT> _Range>
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr iterator insert_range(const_iterator __position, _Range&& __range) {
+      if constexpr (ranges::forward_range<_Range> || ranges::sized_range<_Range>) {
+        auto __n = static_cast<size_type>(ranges::distance(__range));
+        return __insert_with_size(__position, ranges::begin(__range), ranges::end(__range), __n);
+
+      } else {
+        basic_string __temp(from_range, std::forward<_Range>(__range), __alloc());
+        return insert(__position, __temp.data(), __temp.data() + __temp.size());
+      }
+    }
+#endif
+
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 iterator
+  insert(const_iterator __pos, size_type __n, value_type __c) {
+    difference_type __p = __pos - begin();
+    insert(static_cast<size_type>(__p), __n, __c);
+    return begin() + __p;
+  }
+
+  template <class _InputIterator, __enable_if_t<__has_exactly_input_iterator_category<_InputIterator>::value, int> = 0>
+  _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_SINCE_CXX20 iterator
+  insert(const_iterator __pos, _InputIterator __first, _InputIterator __last);
+
+  template <class _ForwardIterator, __enable_if_t<__has_forward_iterator_category<_ForwardIterator>::value, int> = 0>
+  _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_SINCE_CXX20 iterator
+  insert(const_iterator __pos, _ForwardIterator __first, _ForwardIterator __last);
+
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    iterator insert(const_iterator __pos, initializer_list<value_type> __il)
+                    {return insert(__pos, __il.begin(), __il.end());}
+#endif // _LIBCPP_CXX03_LANG
+
+    _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string& erase(size_type __pos = 0, size_type __n = npos);
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    iterator      erase(const_iterator __pos);
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    iterator      erase(const_iterator __first, const_iterator __last);
+
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string&
+  replace(size_type __pos1, size_type __n1, const basic_string& __str) {
+    return replace(__pos1, __n1, __str.data(), __str.size());
+  }
+
+  template <class _Tp, __enable_if_t<__can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value, int> = 0>
+  _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string&
+  replace(size_type __pos1, size_type __n1, const _Tp& __t) {
+    __self_view __sv = __t;
+    return replace(__pos1, __n1, __sv.data(), __sv.size());
+  }
+
+  _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string&
+  replace(size_type __pos1, size_type __n1, const basic_string& __str, size_type __pos2, size_type __n2 = npos);
+
+  template <class _Tp,
+            __enable_if_t<__can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value &&
+                              !__is_same_uncvref<_Tp, basic_string>::value,
+                          int> = 0>
+  _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string&
+  replace(size_type __pos1, size_type __n1, const _Tp& __t, size_type __pos2, size_type __n2 = npos);
+
+  _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string&
+  replace(size_type __pos, size_type __n1, const value_type* __s, size_type __n2);
+  _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string& replace(size_type __pos, size_type __n1, const value_type* __s);
+  _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string& replace(size_type __pos, size_type __n1, size_type __n2, value_type __c);
+
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string&
+  replace(const_iterator __i1, const_iterator __i2, const basic_string& __str) {
+    return replace(
+        static_cast<size_type>(__i1 - begin()), static_cast<size_type>(__i2 - __i1), __str.data(), __str.size());
+  }
+
+  template <class _Tp, __enable_if_t<__can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value, int> = 0>
+  _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string&
+  replace(const_iterator __i1, const_iterator __i2, const _Tp& __t) {
+    __self_view __sv = __t;
+    return replace(__i1 - begin(), __i2 - __i1, __sv);
+  }
+
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string&
+  replace(const_iterator __i1, const_iterator __i2, const value_type* __s, size_type __n) {
+    return replace(static_cast<size_type>(__i1 - begin()), static_cast<size_type>(__i2 - __i1), __s, __n);
+  }
+
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string&
+  replace(const_iterator __i1, const_iterator __i2, const value_type* __s) {
+    return replace(static_cast<size_type>(__i1 - begin()), static_cast<size_type>(__i2 - __i1), __s);
+  }
+
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string&
+  replace(const_iterator __i1, const_iterator __i2, size_type __n, value_type __c) {
+    return replace(static_cast<size_type>(__i1 - begin()), static_cast<size_type>(__i2 - __i1), __n, __c);
+  }
+
+  template <class _InputIterator, __enable_if_t<__has_input_iterator_category<_InputIterator>::value, int> = 0>
+  _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string&
+  replace(const_iterator __i1, const_iterator __i2, _InputIterator __j1, _InputIterator __j2);
+
+#if _LIBCPP_STD_VER >= 23
+  template <_ContainerCompatibleRange<_CharT> _Range>
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr basic_string& replace_with_range(const_iterator __i1, const_iterator __i2, _Range&& __range) {
+    basic_string __temp(from_range, std::forward<_Range>(__range), __alloc());
+    return replace(__i1, __i2, __temp);
+  }
+#endif
+
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    basic_string& replace(const_iterator __i1, const_iterator __i2, initializer_list<value_type> __il)
+        {return replace(__i1, __i2, __il.begin(), __il.end());}
+#endif // _LIBCPP_CXX03_LANG
+
+    _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type copy(value_type* __s, size_type __n, size_type __pos = 0) const;
+
+#if _LIBCPP_STD_VER <= 20
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    basic_string substr(size_type __pos = 0, size_type __n = npos) const {
+      return basic_string(*this, __pos, __n);
+    }
+#else
+    _LIBCPP_HIDE_FROM_ABI constexpr
+    basic_string substr(size_type __pos = 0, size_type __n = npos) const& {
+      return basic_string(*this, __pos, __n);
+    }
+
+    _LIBCPP_HIDE_FROM_ABI constexpr
+    basic_string substr(size_type __pos = 0, size_type __n = npos) && {
+      return basic_string(std::move(*this), __pos, __n);
+    }
+#endif
+
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    void swap(basic_string& __str)
+#if _LIBCPP_STD_VER >= 14
+        _NOEXCEPT;
+#else
+        _NOEXCEPT_(!__alloc_traits::propagate_on_container_swap::value ||
+                    __is_nothrow_swappable<allocator_type>::value);
+#endif
+
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    const value_type* c_str() const _NOEXCEPT {return data();}
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    const value_type* data() const _NOEXCEPT  {return std::__to_address(__get_pointer());}
+#if _LIBCPP_STD_VER >= 17
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    value_type* data()             _NOEXCEPT  {return std::__to_address(__get_pointer());}
+#endif
+
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    allocator_type get_allocator() const _NOEXCEPT {return __alloc();}
+
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    size_type find(const basic_string& __str, size_type __pos = 0) const _NOEXCEPT;
+
+    template <class _Tp, __enable_if_t<__can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value, int> = 0>
+    _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type
+    find(const _Tp& __t, size_type __pos = 0) const _NOEXCEPT;
+
+    _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type find(const value_type* __s, size_type __pos, size_type __n) const _NOEXCEPT;
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    size_type find(const value_type* __s, size_type __pos = 0) const _NOEXCEPT;
+    _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type find(value_type __c, size_type __pos = 0) const _NOEXCEPT;
+
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    size_type rfind(const basic_string& __str, size_type __pos = npos) const _NOEXCEPT;
+
+    template <class _Tp, __enable_if_t<__can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value, int> = 0>
+    _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type
+    rfind(const _Tp& __t, size_type __pos = npos) const _NOEXCEPT;
+
+    _LIBCPP_CONSTEXPR_SINCE_CXX20
+    size_type rfind(const value_type* __s, size_type __pos, size_type __n) const _NOEXCEPT;
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    size_type rfind(const value_type* __s, size_type __pos = npos) const _NOEXCEPT;
+    _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type rfind(value_type __c, size_type __pos = npos) const _NOEXCEPT;
+
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    size_type find_first_of(const basic_string& __str, size_type __pos = 0) const _NOEXCEPT;
+
+    template <class _Tp, __enable_if_t<__can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value, int> = 0>
+    _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type
+    find_first_of(const _Tp& __t, size_type __pos = 0) const _NOEXCEPT;
+
+    _LIBCPP_CONSTEXPR_SINCE_CXX20
+    size_type find_first_of(const value_type* __s, size_type __pos, size_type __n) const _NOEXCEPT;
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    size_type find_first_of(const value_type* __s, size_type __pos = 0) const _NOEXCEPT;
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    size_type find_first_of(value_type __c, size_type __pos = 0) const _NOEXCEPT;
+
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    size_type find_last_of(const basic_string& __str, size_type __pos = npos) const _NOEXCEPT;
+
+    template <class _Tp, __enable_if_t<__can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value, int> = 0>
+    _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type
+    find_last_of(const _Tp& __t, size_type __pos = npos) const _NOEXCEPT;
+
+    _LIBCPP_CONSTEXPR_SINCE_CXX20
+    size_type find_last_of(const value_type* __s, size_type __pos, size_type __n) const _NOEXCEPT;
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    size_type find_last_of(const value_type* __s, size_type __pos = npos) const _NOEXCEPT;
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    size_type find_last_of(value_type __c, size_type __pos = npos) const _NOEXCEPT;
+
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    size_type find_first_not_of(const basic_string& __str, size_type __pos = 0) const _NOEXCEPT;
+
+    template <class _Tp, __enable_if_t<__can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value, int> = 0>
+    _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type
+    find_first_not_of(const _Tp& __t, size_type __pos = 0) const _NOEXCEPT;
+
+    _LIBCPP_CONSTEXPR_SINCE_CXX20
+    size_type find_first_not_of(const value_type* __s, size_type __pos, size_type __n) const _NOEXCEPT;
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    size_type find_first_not_of(const value_type* __s, size_type __pos = 0) const _NOEXCEPT;
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    size_type find_first_not_of(value_type __c, size_type __pos = 0) const _NOEXCEPT;
+
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    size_type find_last_not_of(const basic_string& __str, size_type __pos = npos) const _NOEXCEPT;
+
+    template <class _Tp, __enable_if_t<__can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value, int> = 0>
+    _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type
+    find_last_not_of(const _Tp& __t, size_type __pos = npos) const _NOEXCEPT;
+
+    _LIBCPP_CONSTEXPR_SINCE_CXX20
+    size_type find_last_not_of(const value_type* __s, size_type __pos, size_type __n) const _NOEXCEPT;
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    size_type find_last_not_of(const value_type* __s, size_type __pos = npos) const _NOEXCEPT;
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    size_type find_last_not_of(value_type __c, size_type __pos = npos) const _NOEXCEPT;
+
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    int compare(const basic_string& __str) const _NOEXCEPT;
+
+    template <class _Tp, __enable_if_t<__can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value, int> = 0>
+    _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_SINCE_CXX20 int
+    compare(const _Tp& __t) const _NOEXCEPT;
+
+    template <class _Tp, __enable_if_t<__can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value, int> = 0>
+    _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_SINCE_CXX20 int
+    compare(size_type __pos1, size_type __n1, const _Tp& __t) const;
+
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    int compare(size_type __pos1, size_type __n1, const basic_string& __str) const;
+    _LIBCPP_CONSTEXPR_SINCE_CXX20
+    int compare(size_type __pos1, size_type __n1, const basic_string& __str, size_type __pos2,
+                size_type __n2 = npos) const;
+
+    template <class _Tp,
+              __enable_if_t<__can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value &&
+                                !__is_same_uncvref<_Tp, basic_string>::value,
+                            int> = 0>
+    inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 int
+    compare(size_type __pos1, size_type __n1, const _Tp& __t, size_type __pos2, size_type __n2 = npos) const;
+
+    _LIBCPP_CONSTEXPR_SINCE_CXX20 int compare(const value_type* __s) const _NOEXCEPT;
+    _LIBCPP_CONSTEXPR_SINCE_CXX20 int compare(size_type __pos1, size_type __n1, const value_type* __s) const;
+    _LIBCPP_CONSTEXPR_SINCE_CXX20
+    int compare(size_type __pos1, size_type __n1, const value_type* __s, size_type __n2) const;
+
+#if _LIBCPP_STD_VER >= 20
+    constexpr _LIBCPP_HIDE_FROM_ABI
+    bool starts_with(__self_view __sv) const noexcept
+    { return __self_view(data(), size()).starts_with(__sv); }
+
+    constexpr _LIBCPP_HIDE_FROM_ABI
+    bool starts_with(value_type __c) const noexcept
+    { return !empty() && _Traits::eq(front(), __c); }
+
+    constexpr _LIBCPP_HIDE_FROM_ABI
+    bool starts_with(const value_type* __s) const noexcept
+    { return starts_with(__self_view(__s)); }
+
+    constexpr _LIBCPP_HIDE_FROM_ABI
+    bool ends_with(__self_view __sv) const noexcept
+    { return __self_view(data(), size()).ends_with( __sv); }
+
+    constexpr _LIBCPP_HIDE_FROM_ABI
+    bool ends_with(value_type __c) const noexcept
+    { return !empty() && _Traits::eq(back(), __c); }
+
+    constexpr _LIBCPP_HIDE_FROM_ABI
+    bool ends_with(const value_type* __s) const noexcept
+    { return ends_with(__self_view(__s)); }
+#endif
+
+#if _LIBCPP_STD_VER >= 20
+    constexpr _LIBCPP_HIDE_FROM_ABI
+    bool contains(__self_view __sv) const noexcept
+    { return __self_view(data(), size()).contains(__sv); }
+
+    constexpr _LIBCPP_HIDE_FROM_ABI
+    bool contains(value_type __c) const noexcept
+    { return __self_view(data(), size()).contains(__c); }
+
+    constexpr _LIBCPP_HIDE_FROM_ABI
+    bool contains(const value_type* __s) const
+    { return __self_view(data(), size()).contains(__s); }
+#endif
+
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool __invariants() const;
+
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void __clear_and_shrink() _NOEXCEPT;
+
+private:
+    template<class _Alloc>
+    inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    bool friend operator==(const basic_string<char, char_traits<char>, _Alloc>& __lhs,
+                           const basic_string<char, char_traits<char>, _Alloc>& __rhs) _NOEXCEPT;
+
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void __shrink_or_extend(size_type __target_capacity);
+
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    bool __is_long() const _NOEXCEPT {
+        if (__libcpp_is_constant_evaluated())
+            return true;
+        return __r_.first().__s.__is_long_;
+    }
+
+    static _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void __begin_lifetime(pointer __begin, size_type __n) {
+#if _LIBCPP_STD_VER >= 20
+        if (__libcpp_is_constant_evaluated()) {
+            for (size_type __i = 0; __i != __n; ++__i)
+                std::construct_at(std::addressof(__begin[__i]));
+        }
+#else
+        (void)__begin;
+        (void)__n;
+#endif // _LIBCPP_STD_VER >= 20
+    }
+
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void __default_init() {
+        __r_.first() = __rep();
+        if (__libcpp_is_constant_evaluated()) {
+            size_type __sz = __recommend(0) + 1;
+            pointer __ptr = __alloc_traits::allocate(__alloc(), __sz);
+            __begin_lifetime(__ptr, __sz);
+            __set_long_pointer(__ptr);
+            __set_long_cap(__sz);
+            __set_long_size(0);
+        }
+    }
+
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void __deallocate_constexpr() {
+        if (__libcpp_is_constant_evaluated() && __get_pointer() != nullptr)
+            __alloc_traits::deallocate(__alloc(), __get_pointer(), __get_long_cap());
+    }
+
+    _LIBCPP_CONSTEXPR _LIBCPP_HIDE_FROM_ABI static bool __fits_in_sso(size_type __sz) {
+        // SSO is disabled during constant evaluation because `__is_long` isn't constexpr friendly
+        return !__libcpp_is_constant_evaluated() && (__sz < __min_cap);
+    }
+
+    template <class _Iterator, class _Sentinel>
+    _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI
+    void __assign_trivial(_Iterator __first, _Sentinel __last, size_type __n);
+
+    template <class _Iterator, class _Sentinel>
+    _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI
+    void __assign_with_sentinel(_Iterator __first, _Sentinel __last);
+
+    template <class _ForwardIterator, class _Sentinel>
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
+    iterator __insert_from_safe_copy(size_type __n, size_type __ip, _ForwardIterator __first, _Sentinel __last) {
+        size_type __sz = size();
+        size_type __cap = capacity();
+        value_type* __p;
+        if (__cap - __sz >= __n)
+        {
+            __p = std::__to_address(__get_pointer());
+            size_type __n_move = __sz - __ip;
+            if (__n_move != 0)
+                traits_type::move(__p + __ip + __n, __p + __ip, __n_move);
+        }
+        else
+        {
+            __grow_by_without_replace(__cap, __sz + __n - __cap, __sz, __ip, 0, __n);
+            __p = std::__to_address(__get_long_pointer());
+        }
+        __sz += __n;
+        __set_size(__sz);
+        traits_type::assign(__p[__sz], value_type());
+        for (__p += __ip; __first != __last; ++__p, ++__first)
+            traits_type::assign(*__p, *__first);
+
+        return begin() + __ip;
+    }
+
+    template<class _Iterator, class _Sentinel>
+    _LIBCPP_CONSTEXPR_SINCE_CXX20
+    iterator __insert_with_size(const_iterator __pos, _Iterator __first, _Sentinel __last, size_type __n);
+
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 allocator_type& __alloc() _NOEXCEPT { return __r_.second(); }
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR const allocator_type& __alloc() const _NOEXCEPT { return __r_.second(); }
+
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    void __set_short_size(size_type __s) _NOEXCEPT {
+        _LIBCPP_ASSERT_INTERNAL(
+            __s < __min_cap, "__s should never be greater than or equal to the short string capacity");
+        __r_.first().__s.__size_ = __s;
+        __r_.first().__s.__is_long_ = false;
+    }
+
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    size_type __get_short_size() const _NOEXCEPT {
+        _LIBCPP_ASSERT_INTERNAL(
+            !__r_.first().__s.__is_long_, "String has to be short when trying to get the short size");
+        return __r_.first().__s.__size_;
+    }
+
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    void __set_long_size(size_type __s) _NOEXCEPT
+        {__r_.first().__l.__size_ = __s;}
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    size_type __get_long_size() const _NOEXCEPT
+        {return __r_.first().__l.__size_;}
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    void __set_size(size_type __s) _NOEXCEPT
+        {if (__is_long()) __set_long_size(__s); else __set_short_size(__s);}
+
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    void __set_long_cap(size_type __s) _NOEXCEPT {
+        __r_.first().__l.__cap_ = __s / __endian_factor;
+        __r_.first().__l.__is_long_ = true;
+    }
+
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    size_type __get_long_cap() const _NOEXCEPT {
+        return __r_.first().__l.__cap_ * __endian_factor;
+    }
+
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    void __set_long_pointer(pointer __p) _NOEXCEPT
+        {__r_.first().__l.__data_ = __p;}
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    pointer __get_long_pointer() _NOEXCEPT
+        {return __r_.first().__l.__data_;}
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    const_pointer __get_long_pointer() const _NOEXCEPT
+        {return __r_.first().__l.__data_;}
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    pointer __get_short_pointer() _NOEXCEPT
+        {return pointer_traits<pointer>::pointer_to(__r_.first().__s.__data_[0]);}
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    const_pointer __get_short_pointer() const _NOEXCEPT
+        {return pointer_traits<const_pointer>::pointer_to(__r_.first().__s.__data_[0]);}
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    pointer __get_pointer() _NOEXCEPT
+        {return __is_long() ? __get_long_pointer() : __get_short_pointer();}
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    const_pointer __get_pointer() const _NOEXCEPT
+        {return __is_long() ? __get_long_pointer() : __get_short_pointer();}
+
+    template <size_type __a> static
+        _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+        size_type __align_it(size_type __s) _NOEXCEPT
+            {return (__s + (__a-1)) & ~(__a-1);}
+    enum {__alignment = 16};
+    static _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    size_type __recommend(size_type __s) _NOEXCEPT
+    {
+        if (__s < __min_cap) {
+            if (__libcpp_is_constant_evaluated())
+                return static_cast<size_type>(__min_cap);
+            else
+                return static_cast<size_type>(__min_cap) - 1;
+        }
+        size_type __guess = __align_it<sizeof(value_type) < __alignment ?
+                     __alignment/sizeof(value_type) : 1 > (__s+1) - 1;
+        if (__guess == __min_cap) ++__guess;
+        return __guess;
+    }
+
+    inline _LIBCPP_CONSTEXPR_SINCE_CXX20
+    void __init(const value_type* __s, size_type __sz, size_type __reserve);
+    inline _LIBCPP_CONSTEXPR_SINCE_CXX20
+    void __init(const value_type* __s, size_type __sz);
+    inline _LIBCPP_CONSTEXPR_SINCE_CXX20
+    void __init(size_type __n, value_type __c);
+
+    // Slow path for the (inlined) copy constructor for 'long' strings.
+    // Always externally instantiated and not inlined.
+    // Requires that __s is zero terminated.
+    // The main reason for this function to exist is because for unstable, we
+    // want to allow inlining of the copy constructor. However, we don't want
+    // to call the __init() functions as those are marked as inline which may
+    // result in over-aggressive inlining by the compiler, where our aim is
+    // to only inline the fast path code directly in the ctor.
+    _LIBCPP_CONSTEXPR_SINCE_CXX20 void __init_copy_ctor_external(const value_type* __s, size_type __sz);
+
+    template <class _InputIterator, __enable_if_t<__has_exactly_input_iterator_category<_InputIterator>::value, int> = 0>
+    inline _LIBCPP_CONSTEXPR_SINCE_CXX20 void __init(_InputIterator __first, _InputIterator __last);
+
+    template <class _ForwardIterator, __enable_if_t<__has_forward_iterator_category<_ForwardIterator>::value, int> = 0>
+    inline _LIBCPP_CONSTEXPR_SINCE_CXX20 void __init(_ForwardIterator __first, _ForwardIterator __last);
+
+    template <class _InputIterator, class _Sentinel>
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    void __init_with_sentinel(_InputIterator __first, _Sentinel __last);
+    template <class _InputIterator, class _Sentinel>
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    void __init_with_size(_InputIterator __first, _Sentinel __last, size_type __sz);
+
+    _LIBCPP_CONSTEXPR_SINCE_CXX20
+#if _LIBCPP_ABI_VERSION >= 2 //  We want to use the function in the dylib in ABIv1
+    _LIBCPP_HIDE_FROM_ABI
+#endif
+    _LIBCPP_DEPRECATED_("use __grow_by_without_replace")
+    void __grow_by(size_type __old_cap, size_type __delta_cap, size_type __old_sz,
+                   size_type __n_copy,  size_type __n_del,     size_type __n_add = 0);
+    _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI
+    void __grow_by_without_replace(size_type __old_cap, size_type __delta_cap, size_type __old_sz,
+                   size_type __n_copy,  size_type __n_del,     size_type __n_add = 0);
+    _LIBCPP_CONSTEXPR_SINCE_CXX20
+    void __grow_by_and_replace(size_type __old_cap, size_type __delta_cap, size_type __old_sz,
+                               size_type __n_copy,  size_type __n_del,
+                               size_type __n_add, const value_type* __p_new_stuff);
+
+    // __assign_no_alias is invoked for assignment operations where we
+    // have proof that the input does not alias the current instance.
+    // For example, operator=(basic_string) performs a 'self' check.
+    template <bool __is_short>
+    _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string& __assign_no_alias(const value_type* __s, size_type __n);
+
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void __erase_to_end(size_type __pos) {
+    __null_terminate_at(std::__to_address(__get_pointer()), __pos);
+  }
+
+    // __erase_external_with_move is invoked for erase() invocations where
+    // `n ~= npos`, likely requiring memory moves on the string data.
+    _LIBCPP_CONSTEXPR_SINCE_CXX20 void __erase_external_with_move(size_type __pos, size_type __n);
+
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    void __copy_assign_alloc(const basic_string& __str)
+        {__copy_assign_alloc(__str, integral_constant<bool,
+                      __alloc_traits::propagate_on_container_copy_assignment::value>());}
+
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    void __copy_assign_alloc(const basic_string& __str, true_type)
+        {
+            if (__alloc() == __str.__alloc())
+                __alloc() = __str.__alloc();
+            else
+            {
+                if (!__str.__is_long())
+                {
+                    __clear_and_shrink();
+                    __alloc() = __str.__alloc();
+                }
+                else
+                {
+                    allocator_type __a = __str.__alloc();
+                    auto __allocation = std::__allocate_at_least(__a, __str.__get_long_cap());
+                    __begin_lifetime(__allocation.ptr, __allocation.count);
+                    if (__is_long())
+                        __alloc_traits::deallocate(__alloc(), __get_long_pointer(), __get_long_cap());
+                    __alloc() = std::move(__a);
+                    __set_long_pointer(__allocation.ptr);
+                    __set_long_cap(__allocation.count);
+                    __set_long_size(__str.size());
+                }
+            }
+        }
+
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    void __copy_assign_alloc(const basic_string&, false_type) _NOEXCEPT
+        {}
+
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    void __move_assign(basic_string& __str, false_type)
+        _NOEXCEPT_(__alloc_traits::is_always_equal::value);
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    void __move_assign(basic_string& __str, true_type)
+#if _LIBCPP_STD_VER >= 17
+        _NOEXCEPT;
+#else
+        _NOEXCEPT_(is_nothrow_move_assignable<allocator_type>::value);
+#endif
+#endif
+
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    void
+    __move_assign_alloc(basic_string& __str)
+        _NOEXCEPT_(
+            !__alloc_traits::propagate_on_container_move_assignment::value ||
+            is_nothrow_move_assignable<allocator_type>::value)
+    {__move_assign_alloc(__str, integral_constant<bool,
+                      __alloc_traits::propagate_on_container_move_assignment::value>());}
+
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    void __move_assign_alloc(basic_string& __c, true_type)
+        _NOEXCEPT_(is_nothrow_move_assignable<allocator_type>::value)
+        {
+            __alloc() = std::move(__c.__alloc());
+        }
+
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    void __move_assign_alloc(basic_string&, false_type)
+        _NOEXCEPT
+        {}
+
+    _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string& __assign_external(const value_type* __s);
+    _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string& __assign_external(const value_type* __s, size_type __n);
+
+    // Assigns the value in __s, guaranteed to be __n < __min_cap in length.
+    inline basic_string& __assign_short(const value_type* __s, size_type __n) {
+      pointer __p = __is_long()
+                        ? (__set_long_size(__n), __get_long_pointer())
+                        : (__set_short_size(__n), __get_short_pointer());
+      traits_type::move(std::__to_address(__p), __s, __n);
+      traits_type::assign(__p[__n], value_type());
+      return *this;
+    }
+
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    basic_string& __null_terminate_at(value_type* __p, size_type __newsz) {
+      __set_size(__newsz);
+      traits_type::assign(__p[__newsz], value_type());
+      return *this;
+    }
+
+    template <class _Tp>
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool __addr_in_range(const _Tp& __v) const {
+      return std::__is_pointer_in_range(data(), data() + size() + 1, std::addressof(__v));
+    }
+
+    _LIBCPP_NORETURN _LIBCPP_HIDE_FROM_ABI
+    void __throw_length_error() const {
+        std::__throw_length_error("basic_string");
+    }
+
+    _LIBCPP_NORETURN _LIBCPP_HIDE_FROM_ABI
+    void __throw_out_of_range() const {
+        std::__throw_out_of_range("basic_string");
+    }
+
+    friend _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string operator+<>(const basic_string&, const basic_string&);
+    friend _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string operator+<>(const value_type*, const basic_string&);
+    friend _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string operator+<>(value_type, const basic_string&);
+    friend _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string operator+<>(const basic_string&, const value_type*);
+    friend _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string operator+<>(const basic_string&, value_type);
+};
+
+// These declarations must appear before any functions are implicitly used
+// so that they have the correct visibility specifier.
+#define _LIBCPP_DECLARE(...) extern template __VA_ARGS__;
+#ifdef _LIBCPP_ABI_STRING_OPTIMIZED_EXTERNAL_INSTANTIATION
+    _LIBCPP_STRING_UNSTABLE_EXTERN_TEMPLATE_LIST(_LIBCPP_DECLARE, char)
+#   ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+        _LIBCPP_STRING_UNSTABLE_EXTERN_TEMPLATE_LIST(_LIBCPP_DECLARE, wchar_t)
+#   endif
+#else
+    _LIBCPP_STRING_V1_EXTERN_TEMPLATE_LIST(_LIBCPP_DECLARE, char)
+#   ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+        _LIBCPP_STRING_V1_EXTERN_TEMPLATE_LIST(_LIBCPP_DECLARE, wchar_t)
+#   endif
+#endif
+#undef _LIBCPP_DECLARE
+
+
+#if _LIBCPP_STD_VER >= 17
+template<class _InputIterator,
+         class _CharT = __iter_value_type<_InputIterator>,
+         class _Allocator = allocator<_CharT>,
+         class = enable_if_t<__has_input_iterator_category<_InputIterator>::value>,
+         class = enable_if_t<__is_allocator<_Allocator>::value>
+         >
+basic_string(_InputIterator, _InputIterator, _Allocator = _Allocator())
+  -> basic_string<_CharT, char_traits<_CharT>, _Allocator>;
+
+template<class _CharT,
+         class _Traits,
+         class _Allocator = allocator<_CharT>,
+         class = enable_if_t<__is_allocator<_Allocator>::value>
+         >
+explicit basic_string(basic_string_view<_CharT, _Traits>, const _Allocator& = _Allocator())
+  -> basic_string<_CharT, _Traits, _Allocator>;
+
+template<class _CharT,
+         class _Traits,
+         class _Allocator = allocator<_CharT>,
+         class = enable_if_t<__is_allocator<_Allocator>::value>,
+         class _Sz = typename allocator_traits<_Allocator>::size_type
+         >
+basic_string(basic_string_view<_CharT, _Traits>, _Sz, _Sz, const _Allocator& = _Allocator())
+  -> basic_string<_CharT, _Traits, _Allocator>;
+#endif
+
+#if _LIBCPP_STD_VER >= 23
+template <ranges::input_range _Range,
+          class _Allocator = allocator<ranges::range_value_t<_Range>>,
+          class = enable_if_t<__is_allocator<_Allocator>::value>
+          >
+basic_string(from_range_t, _Range&&, _Allocator = _Allocator())
+  -> basic_string<ranges::range_value_t<_Range>, char_traits<ranges::range_value_t<_Range>>, _Allocator>;
+#endif
+
+template <class _CharT, class _Traits, class _Allocator>
+_LIBCPP_CONSTEXPR_SINCE_CXX20
+void basic_string<_CharT, _Traits, _Allocator>::__init(const value_type* __s,
+                                                       size_type __sz,
+                                                       size_type __reserve)
+{
+    if (__libcpp_is_constant_evaluated())
+        __r_.first() = __rep();
+    if (__reserve > max_size())
+        __throw_length_error();
+    pointer __p;
+    if (__fits_in_sso(__reserve))
+    {
+        __set_short_size(__sz);
+        __p = __get_short_pointer();
+    }
+    else
+    {
+        auto __allocation = std::__allocate_at_least(__alloc(), __recommend(__reserve) + 1);
+        __p = __allocation.ptr;
+        __begin_lifetime(__p, __allocation.count);
+        __set_long_pointer(__p);
+        __set_long_cap(__allocation.count);
+        __set_long_size(__sz);
+    }
+    traits_type::copy(std::__to_address(__p), __s, __sz);
+    traits_type::assign(__p[__sz], value_type());
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+_LIBCPP_CONSTEXPR_SINCE_CXX20
+void
+basic_string<_CharT, _Traits, _Allocator>::__init(const value_type* __s, size_type __sz)
+{
+    if (__libcpp_is_constant_evaluated())
+        __r_.first() = __rep();
+    if (__sz > max_size())
+        __throw_length_error();
+    pointer __p;
+    if (__fits_in_sso(__sz))
+    {
+        __set_short_size(__sz);
+        __p = __get_short_pointer();
+    }
+    else
+    {
+        auto __allocation = std::__allocate_at_least(__alloc(), __recommend(__sz) + 1);
+        __p = __allocation.ptr;
+        __begin_lifetime(__p, __allocation.count);
+        __set_long_pointer(__p);
+        __set_long_cap(__allocation.count);
+        __set_long_size(__sz);
+    }
+    traits_type::copy(std::__to_address(__p), __s, __sz);
+    traits_type::assign(__p[__sz], value_type());
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+_LIBCPP_CONSTEXPR_SINCE_CXX20
+void basic_string<_CharT, _Traits, _Allocator>::__init_copy_ctor_external(
+    const value_type* __s, size_type __sz) {
+  if (__libcpp_is_constant_evaluated())
+    __r_.first() = __rep();
+
+  pointer __p;
+  if (__fits_in_sso(__sz)) {
+    __p = __get_short_pointer();
+    __set_short_size(__sz);
+  } else {
+    if (__sz > max_size())
+      __throw_length_error();
+    auto __allocation = std::__allocate_at_least(__alloc(), __recommend(__sz) + 1);
+    __p = __allocation.ptr;
+    __begin_lifetime(__p, __allocation.count);
+    __set_long_pointer(__p);
+    __set_long_cap(__allocation.count);
+    __set_long_size(__sz);
+  }
+  traits_type::copy(std::__to_address(__p), __s, __sz + 1);
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+_LIBCPP_CONSTEXPR_SINCE_CXX20
+void
+basic_string<_CharT, _Traits, _Allocator>::__init(size_type __n, value_type __c)
+{
+    if (__libcpp_is_constant_evaluated())
+        __r_.first() = __rep();
+
+    if (__n > max_size())
+        __throw_length_error();
+    pointer __p;
+    if (__fits_in_sso(__n))
+    {
+        __set_short_size(__n);
+        __p = __get_short_pointer();
+    }
+    else
+    {
+        auto __allocation = std::__allocate_at_least(__alloc(), __recommend(__n) + 1);
+        __p = __allocation.ptr;
+        __begin_lifetime(__p, __allocation.count);
+        __set_long_pointer(__p);
+        __set_long_cap(__allocation.count);
+        __set_long_size(__n);
+    }
+    traits_type::assign(std::__to_address(__p), __n, __c);
+    traits_type::assign(__p[__n], value_type());
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+template <class _InputIterator, __enable_if_t<__has_exactly_input_iterator_category<_InputIterator>::value, int> >
+_LIBCPP_CONSTEXPR_SINCE_CXX20
+void basic_string<_CharT, _Traits, _Allocator>::__init(_InputIterator __first, _InputIterator __last)
+{
+  __init_with_sentinel(std::move(__first), std::move(__last));
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+template <class _InputIterator, class _Sentinel>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+void basic_string<_CharT, _Traits, _Allocator>::__init_with_sentinel(_InputIterator __first, _Sentinel __last) {
+    __default_init();
+
+#ifndef _LIBCPP_HAS_NO_EXCEPTIONS
+    try
+    {
+#endif // _LIBCPP_HAS_NO_EXCEPTIONS
+    for (; __first != __last; ++__first)
+        push_back(*__first);
+#ifndef _LIBCPP_HAS_NO_EXCEPTIONS
+    }
+    catch (...)
+    {
+        if (__is_long())
+            __alloc_traits::deallocate(__alloc(), __get_long_pointer(), __get_long_cap());
+        throw;
+    }
+#endif // _LIBCPP_HAS_NO_EXCEPTIONS
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+template <class _ForwardIterator, __enable_if_t<__has_forward_iterator_category<_ForwardIterator>::value, int> >
+_LIBCPP_CONSTEXPR_SINCE_CXX20 void
+basic_string<_CharT, _Traits, _Allocator>::__init(_ForwardIterator __first, _ForwardIterator __last)
+{
+  size_type __sz = static_cast<size_type>(std::distance(__first, __last));
+  __init_with_size(__first, __last, __sz);
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+template <class _InputIterator, class _Sentinel>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+void basic_string<_CharT, _Traits, _Allocator>::__init_with_size(
+    _InputIterator __first, _Sentinel __last, size_type __sz) {
+    if (__libcpp_is_constant_evaluated())
+        __r_.first() = __rep();
+
+    if (__sz > max_size())
+        __throw_length_error();
+
+    pointer __p;
+    if (__fits_in_sso(__sz))
+    {
+        __set_short_size(__sz);
+        __p = __get_short_pointer();
+
+    }
+    else
+    {
+        auto __allocation = std::__allocate_at_least(__alloc(), __recommend(__sz) + 1);
+        __p = __allocation.ptr;
+        __begin_lifetime(__p, __allocation.count);
+        __set_long_pointer(__p);
+        __set_long_cap(__allocation.count);
+        __set_long_size(__sz);
+    }
+
+#ifndef _LIBCPP_HAS_NO_EXCEPTIONS
+    try
+    {
+#endif  // _LIBCPP_HAS_NO_EXCEPTIONS
+    for (; __first != __last; ++__first, (void) ++__p)
+        traits_type::assign(*__p, *__first);
+    traits_type::assign(*__p, value_type());
+#ifndef _LIBCPP_HAS_NO_EXCEPTIONS
+    }
+    catch (...)
+    {
+        if (__is_long())
+            __alloc_traits::deallocate(__alloc(), __get_long_pointer(), __get_long_cap());
+        throw;
+    }
+#endif  // _LIBCPP_HAS_NO_EXCEPTIONS
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+_LIBCPP_CONSTEXPR_SINCE_CXX20
+void
+basic_string<_CharT, _Traits, _Allocator>::__grow_by_and_replace
+    (size_type __old_cap, size_type __delta_cap, size_type __old_sz,
+     size_type __n_copy,  size_type __n_del,     size_type __n_add, const value_type* __p_new_stuff)
+{
+    size_type __ms = max_size();
+    if (__delta_cap > __ms - __old_cap - 1)
+        __throw_length_error();
+    pointer __old_p = __get_pointer();
+    size_type __cap = __old_cap < __ms / 2 - __alignment ?
+                          __recommend(std::max(__old_cap + __delta_cap, 2 * __old_cap)) :
+                          __ms - 1;
+    auto __allocation = std::__allocate_at_least(__alloc(), __cap + 1);
+    pointer __p = __allocation.ptr;
+    __begin_lifetime(__p, __allocation.count);
+    if (__n_copy != 0)
+        traits_type::copy(std::__to_address(__p),
+                          std::__to_address(__old_p), __n_copy);
+    if (__n_add != 0)
+        traits_type::copy(std::__to_address(__p) + __n_copy, __p_new_stuff, __n_add);
+    size_type __sec_cp_sz = __old_sz - __n_del - __n_copy;
+    if (__sec_cp_sz != 0)
+        traits_type::copy(std::__to_address(__p) + __n_copy + __n_add,
+                          std::__to_address(__old_p) + __n_copy + __n_del, __sec_cp_sz);
+    if (__old_cap+1 != __min_cap || __libcpp_is_constant_evaluated())
+        __alloc_traits::deallocate(__alloc(), __old_p, __old_cap+1);
+    __set_long_pointer(__p);
+    __set_long_cap(__allocation.count);
+    __old_sz = __n_copy + __n_add + __sec_cp_sz;
+    __set_long_size(__old_sz);
+    traits_type::assign(__p[__old_sz], value_type());
+}
+
+// __grow_by is deprecated because it does not set the size. It may not update the size when the size is changed, and it
+// may also not set the size at all when the string was short initially. This leads to unpredictable size value. It is
+// not removed or changed to avoid breaking the ABI.
+template <class _CharT, class _Traits, class _Allocator>
+void
+_LIBCPP_CONSTEXPR_SINCE_CXX20
+#if _LIBCPP_ABI_VERSION >= 2 // We want to use the function in the dylib in ABIv1
+    _LIBCPP_HIDE_FROM_ABI
+#endif
+    _LIBCPP_DEPRECATED_("use __grow_by_without_replace")
+basic_string<_CharT, _Traits, _Allocator>::__grow_by(size_type __old_cap, size_type __delta_cap, size_type __old_sz,
+                                                     size_type __n_copy,  size_type __n_del,     size_type __n_add)
+{
+    size_type __ms = max_size();
+    if (__delta_cap > __ms - __old_cap)
+        __throw_length_error();
+    pointer __old_p = __get_pointer();
+    size_type __cap = __old_cap < __ms / 2 - __alignment ?
+                          __recommend(std::max(__old_cap + __delta_cap, 2 * __old_cap)) :
+                          __ms - 1;
+    auto __allocation = std::__allocate_at_least(__alloc(), __cap + 1);
+    pointer __p = __allocation.ptr;
+    __begin_lifetime(__p, __allocation.count);
+    if (__n_copy != 0)
+        traits_type::copy(std::__to_address(__p),
+                          std::__to_address(__old_p), __n_copy);
+    size_type __sec_cp_sz = __old_sz - __n_del - __n_copy;
+    if (__sec_cp_sz != 0)
+        traits_type::copy(std::__to_address(__p) + __n_copy + __n_add,
+                          std::__to_address(__old_p) + __n_copy + __n_del,
+                          __sec_cp_sz);
+    if (__libcpp_is_constant_evaluated() || __old_cap + 1 != __min_cap)
+        __alloc_traits::deallocate(__alloc(), __old_p, __old_cap + 1);
+    __set_long_pointer(__p);
+    __set_long_cap(__allocation.count);
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+void _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI
+basic_string<_CharT, _Traits, _Allocator>::__grow_by_without_replace(
+    size_type __old_cap,
+    size_type __delta_cap,
+    size_type __old_sz,
+    size_type __n_copy,
+    size_type __n_del,
+    size_type __n_add) {
+    _LIBCPP_SUPPRESS_DEPRECATED_PUSH
+    __grow_by(__old_cap, __delta_cap, __old_sz, __n_copy, __n_del, __n_add);
+    _LIBCPP_SUPPRESS_DEPRECATED_POP
+    __set_long_size(__old_sz - __n_del + __n_add);
+}
+
+// assign
+
+template <class _CharT, class _Traits, class _Allocator>
+template <bool __is_short>
+_LIBCPP_CONSTEXPR_SINCE_CXX20
+basic_string<_CharT, _Traits, _Allocator>&
+basic_string<_CharT, _Traits, _Allocator>::__assign_no_alias(
+    const value_type* __s, size_type __n) {
+  size_type __cap = __is_short ? static_cast<size_type>(__min_cap) : __get_long_cap();
+  if (__n < __cap) {
+    pointer __p = __is_short ? __get_short_pointer() : __get_long_pointer();
+    __is_short ? __set_short_size(__n) : __set_long_size(__n);
+    traits_type::copy(std::__to_address(__p), __s, __n);
+    traits_type::assign(__p[__n], value_type());
+  } else {
+    size_type __sz = __is_short ? __get_short_size() : __get_long_size();
+    __grow_by_and_replace(__cap - 1, __n - __cap + 1, __sz, 0, __sz, __n, __s);
+  }
+  return *this;
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+_LIBCPP_CONSTEXPR_SINCE_CXX20
+basic_string<_CharT, _Traits, _Allocator>&
+basic_string<_CharT, _Traits, _Allocator>::__assign_external(
+    const value_type* __s, size_type __n) {
+  size_type __cap = capacity();
+  if (__cap >= __n) {
+    value_type* __p = std::__to_address(__get_pointer());
+    traits_type::move(__p, __s, __n);
+    return __null_terminate_at(__p, __n);
+  } else {
+    size_type __sz = size();
+    __grow_by_and_replace(__cap, __n - __cap, __sz, 0, __sz, __n, __s);
+    return *this;
+  }
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+_LIBCPP_CONSTEXPR_SINCE_CXX20
+basic_string<_CharT, _Traits, _Allocator>&
+basic_string<_CharT, _Traits, _Allocator>::assign(const value_type* __s, size_type __n)
+{
+    _LIBCPP_ASSERT_UNCATEGORIZED(__n == 0 || __s != nullptr, "string::assign received nullptr");
+    return (__builtin_constant_p(__n) && __fits_in_sso(__n))
+               ? __assign_short(__s, __n)
+               : __assign_external(__s, __n);
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+_LIBCPP_CONSTEXPR_SINCE_CXX20
+basic_string<_CharT, _Traits, _Allocator>&
+basic_string<_CharT, _Traits, _Allocator>::assign(size_type __n, value_type __c)
+{
+    size_type __cap = capacity();
+    if (__cap < __n)
+    {
+        size_type __sz = size();
+        __grow_by_without_replace(__cap, __n - __cap, __sz, 0, __sz);
+    }
+    value_type* __p = std::__to_address(__get_pointer());
+    traits_type::assign(__p, __n, __c);
+    return __null_terminate_at(__p, __n);
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+_LIBCPP_CONSTEXPR_SINCE_CXX20
+basic_string<_CharT, _Traits, _Allocator>&
+basic_string<_CharT, _Traits, _Allocator>::operator=(value_type __c)
+{
+    pointer __p;
+    if (__is_long())
+    {
+        __p = __get_long_pointer();
+        __set_long_size(1);
+    }
+    else
+    {
+        __p = __get_short_pointer();
+        __set_short_size(1);
+    }
+    traits_type::assign(*__p, __c);
+    traits_type::assign(*++__p, value_type());
+    return *this;
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+_LIBCPP_CONSTEXPR_SINCE_CXX20
+basic_string<_CharT, _Traits, _Allocator>&
+basic_string<_CharT, _Traits, _Allocator>::operator=(const basic_string& __str)
+{
+  if (this != std::addressof(__str)) {
+    __copy_assign_alloc(__str);
+    if (!__is_long()) {
+      if (!__str.__is_long()) {
+        __r_.first() = __str.__r_.first();
+      } else {
+        return __assign_no_alias<true>(__str.data(), __str.size());
+      }
+    } else {
+      return __assign_no_alias<false>(__str.data(), __str.size());
+    }
+  }
+  return *this;
+}
+
+#ifndef _LIBCPP_CXX03_LANG
+
+template <class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_CONSTEXPR_SINCE_CXX20
+void
+basic_string<_CharT, _Traits, _Allocator>::__move_assign(basic_string& __str, false_type)
+    _NOEXCEPT_(__alloc_traits::is_always_equal::value)
+{
+    if (__alloc() != __str.__alloc())
+        assign(__str);
+    else
+        __move_assign(__str, true_type());
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_CONSTEXPR_SINCE_CXX20
+void
+basic_string<_CharT, _Traits, _Allocator>::__move_assign(basic_string& __str, true_type)
+#if _LIBCPP_STD_VER >= 17
+    _NOEXCEPT
+#else
+    _NOEXCEPT_(is_nothrow_move_assignable<allocator_type>::value)
+#endif
+{
+  if (__is_long()) {
+    __alloc_traits::deallocate(__alloc(), __get_long_pointer(),
+                               __get_long_cap());
+#if _LIBCPP_STD_VER <= 14
+    if (!is_nothrow_move_assignable<allocator_type>::value) {
+      __set_short_size(0);
+      traits_type::assign(__get_short_pointer()[0], value_type());
+    }
+#endif
+  }
+  __move_assign_alloc(__str);
+  __r_.first() = __str.__r_.first();
+  if (__libcpp_is_constant_evaluated()) {
+    __str.__default_init();
+  } else {
+    __str.__set_short_size(0);
+    traits_type::assign(__str.__get_short_pointer()[0], value_type());
+  }
+}
+
+#endif
+
+template <class _CharT, class _Traits, class _Allocator>
+template<class _InputIterator, __enable_if_t<__has_exactly_input_iterator_category<_InputIterator>::value, int> >
+_LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string<_CharT, _Traits, _Allocator>&
+basic_string<_CharT, _Traits, _Allocator>::assign(_InputIterator __first, _InputIterator __last)
+{
+  __assign_with_sentinel(__first, __last);
+  return *this;
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+template <class _InputIterator, class _Sentinel>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+void
+basic_string<_CharT, _Traits, _Allocator>::__assign_with_sentinel(_InputIterator __first, _Sentinel __last) {
+  const basic_string __temp(__init_with_sentinel_tag(), std::move(__first), std::move(__last), __alloc());
+  assign(__temp.data(), __temp.size());
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+template<class _ForwardIterator, __enable_if_t<__has_forward_iterator_category<_ForwardIterator>::value, int> >
+_LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string<_CharT, _Traits, _Allocator>&
+basic_string<_CharT, _Traits, _Allocator>::assign(_ForwardIterator __first, _ForwardIterator __last)
+{
+  if (__string_is_trivial_iterator<_ForwardIterator>::value) {
+    size_type __n = static_cast<size_type>(std::distance(__first, __last));
+    __assign_trivial(__first, __last, __n);
+  } else {
+    __assign_with_sentinel(__first, __last);
+  }
+
+  return *this;
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+template <class _Iterator, class _Sentinel>
+_LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI
+void
+basic_string<_CharT, _Traits, _Allocator>::__assign_trivial(_Iterator __first, _Sentinel __last, size_type __n) {
+  _LIBCPP_ASSERT_INTERNAL(
+      __string_is_trivial_iterator<_Iterator>::value, "The iterator type given to `__assign_trivial` must be trivial");
+
+  size_type __cap = capacity();
+  if (__cap < __n) {
+    // Unlike `append` functions, if the input range points into the string itself, there is no case that the input
+    // range could get invalidated by reallocation:
+    // 1. If the input range is a subset of the string itself, its size cannot exceed the capacity of the string,
+    //    thus no reallocation would happen.
+    // 2. In the exotic case where the input range is the byte representation of the string itself, the string
+    //    object itself stays valid even if reallocation happens.
+    size_type __sz = size();
+    __grow_by_without_replace(__cap, __n - __cap, __sz, 0, __sz);
+    }
+    pointer __p = __get_pointer();
+    for (; __first != __last; ++__p, (void) ++__first)
+        traits_type::assign(*__p, *__first);
+    traits_type::assign(*__p, value_type());
+    __set_size(__n);
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+_LIBCPP_CONSTEXPR_SINCE_CXX20
+basic_string<_CharT, _Traits, _Allocator>&
+basic_string<_CharT, _Traits, _Allocator>::assign(const basic_string& __str, size_type __pos, size_type __n)
+{
+    size_type __sz = __str.size();
+    if (__pos > __sz)
+        __throw_out_of_range();
+    return assign(__str.data() + __pos, std::min(__n, __sz - __pos));
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+template <class _Tp,
+          __enable_if_t<__can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value &&
+                            !__is_same_uncvref<_Tp, basic_string<_CharT, _Traits, _Allocator> >::value,
+                        int> >
+_LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string<_CharT, _Traits, _Allocator>&
+basic_string<_CharT, _Traits, _Allocator>::assign(const _Tp& __t, size_type __pos, size_type __n) {
+    __self_view __sv = __t;
+    size_type __sz = __sv.size();
+    if (__pos > __sz)
+        __throw_out_of_range();
+    return assign(__sv.data() + __pos, std::min(__n, __sz - __pos));
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+_LIBCPP_CONSTEXPR_SINCE_CXX20
+basic_string<_CharT, _Traits, _Allocator>&
+basic_string<_CharT, _Traits, _Allocator>::__assign_external(const value_type* __s) {
+  return __assign_external(__s, traits_type::length(__s));
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+_LIBCPP_CONSTEXPR_SINCE_CXX20
+basic_string<_CharT, _Traits, _Allocator>&
+basic_string<_CharT, _Traits, _Allocator>::assign(const value_type* __s)
+{
+    _LIBCPP_ASSERT_UNCATEGORIZED(__s != nullptr, "string::assign received nullptr");
+    return __builtin_constant_p(*__s)
+               ? (__fits_in_sso(traits_type::length(__s))
+                      ? __assign_short(__s, traits_type::length(__s))
+                      : __assign_external(__s, traits_type::length(__s)))
+               : __assign_external(__s);
+}
+// append
+
+template <class _CharT, class _Traits, class _Allocator>
+_LIBCPP_CONSTEXPR_SINCE_CXX20
+basic_string<_CharT, _Traits, _Allocator>&
+basic_string<_CharT, _Traits, _Allocator>::append(const value_type* __s, size_type __n)
+{
+    _LIBCPP_ASSERT_UNCATEGORIZED(__n == 0 || __s != nullptr, "string::append received nullptr");
+    size_type __cap = capacity();
+    size_type __sz = size();
+    if (__cap - __sz >= __n)
+    {
+        if (__n)
+        {
+            value_type* __p = std::__to_address(__get_pointer());
+            traits_type::copy(__p + __sz, __s, __n);
+            __sz += __n;
+            __set_size(__sz);
+            traits_type::assign(__p[__sz], value_type());
+        }
+    }
+    else
+        __grow_by_and_replace(__cap, __sz + __n - __cap, __sz, __sz, 0, __n, __s);
+    return *this;
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+_LIBCPP_CONSTEXPR_SINCE_CXX20
+basic_string<_CharT, _Traits, _Allocator>&
+basic_string<_CharT, _Traits, _Allocator>::append(size_type __n, value_type __c)
+{
+    if (__n)
+    {
+        size_type __cap = capacity();
+        size_type __sz = size();
+        if (__cap - __sz < __n)
+            __grow_by_without_replace(__cap, __sz + __n - __cap, __sz, __sz, 0);
+        pointer __p = __get_pointer();
+        traits_type::assign(std::__to_address(__p) + __sz, __n, __c);
+        __sz += __n;
+        __set_size(__sz);
+        traits_type::assign(__p[__sz], value_type());
+    }
+    return *this;
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+_LIBCPP_CONSTEXPR_SINCE_CXX20 inline void
+basic_string<_CharT, _Traits, _Allocator>::__append_default_init(size_type __n)
+{
+    if (__n)
+    {
+        size_type __cap = capacity();
+        size_type __sz = size();
+        if (__cap - __sz < __n)
+            __grow_by_without_replace(__cap, __sz + __n - __cap, __sz, __sz, 0);
+        pointer __p = __get_pointer();
+        __sz += __n;
+        __set_size(__sz);
+        traits_type::assign(__p[__sz], value_type());
+    }
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+_LIBCPP_CONSTEXPR_SINCE_CXX20
+void
+basic_string<_CharT, _Traits, _Allocator>::push_back(value_type __c)
+{
+    bool __is_short = !__is_long();
+    size_type __cap;
+    size_type __sz;
+    if (__is_short)
+    {
+        __cap = __min_cap - 1;
+        __sz = __get_short_size();
+    }
+    else
+    {
+        __cap = __get_long_cap() - 1;
+        __sz = __get_long_size();
+    }
+    if (__sz == __cap)
+    {
+        __grow_by_without_replace(__cap, 1, __sz, __sz, 0);
+        __is_short = false; // the string is always long after __grow_by
+    }
+    pointer __p = __get_pointer();
+    if (__is_short)
+    {
+        __p = __get_short_pointer() + __sz;
+        __set_short_size(__sz+1);
+    }
+    else
+    {
+        __p = __get_long_pointer() + __sz;
+        __set_long_size(__sz+1);
+    }
+    traits_type::assign(*__p, __c);
+    traits_type::assign(*++__p, value_type());
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+template<class _ForwardIterator, __enable_if_t<__has_forward_iterator_category<_ForwardIterator>::value, int> >
+_LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string<_CharT, _Traits, _Allocator>&
+basic_string<_CharT, _Traits, _Allocator>::append(
+    _ForwardIterator __first, _ForwardIterator __last)
+{
+    size_type __sz = size();
+    size_type __cap = capacity();
+    size_type __n = static_cast<size_type>(std::distance(__first, __last));
+    if (__n)
+    {
+        if (__string_is_trivial_iterator<_ForwardIterator>::value &&
+            !__addr_in_range(*__first))
+        {
+            if (__cap - __sz < __n)
+              __grow_by_without_replace(__cap, __sz + __n - __cap, __sz, __sz, 0);
+            pointer __p = __get_pointer() + __sz;
+            for (; __first != __last; ++__p, (void) ++__first)
+                traits_type::assign(*__p, *__first);
+            traits_type::assign(*__p, value_type());
+            __set_size(__sz + __n);
+        }
+        else
+        {
+            const basic_string __temp(__first, __last, __alloc());
+            append(__temp.data(), __temp.size());
+        }
+    }
+    return *this;
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+_LIBCPP_CONSTEXPR_SINCE_CXX20
+basic_string<_CharT, _Traits, _Allocator>&
+basic_string<_CharT, _Traits, _Allocator>::append(const basic_string& __str, size_type __pos, size_type __n)
+{
+    size_type __sz = __str.size();
+    if (__pos > __sz)
+        __throw_out_of_range();
+    return append(__str.data() + __pos, std::min(__n, __sz - __pos));
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+template <class _Tp,
+          __enable_if_t<__can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value &&
+                            !__is_same_uncvref<_Tp, basic_string<_CharT, _Traits, _Allocator> >::value,
+                        int> >
+_LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string<_CharT, _Traits, _Allocator>&
+basic_string<_CharT, _Traits, _Allocator>::append(const _Tp& __t, size_type __pos, size_type __n) {
+    __self_view __sv = __t;
+    size_type __sz = __sv.size();
+    if (__pos > __sz)
+        __throw_out_of_range();
+    return append(__sv.data() + __pos, std::min(__n, __sz - __pos));
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+_LIBCPP_CONSTEXPR_SINCE_CXX20
+basic_string<_CharT, _Traits, _Allocator>&
+basic_string<_CharT, _Traits, _Allocator>::append(const value_type* __s)
+{
+    _LIBCPP_ASSERT_UNCATEGORIZED(__s != nullptr, "string::append received nullptr");
+    return append(__s, traits_type::length(__s));
+}
+
+// insert
+
+template <class _CharT, class _Traits, class _Allocator>
+_LIBCPP_CONSTEXPR_SINCE_CXX20
+basic_string<_CharT, _Traits, _Allocator>&
+basic_string<_CharT, _Traits, _Allocator>::insert(size_type __pos, const value_type* __s, size_type __n)
+{
+    _LIBCPP_ASSERT_UNCATEGORIZED(__n == 0 || __s != nullptr, "string::insert received nullptr");
+    size_type __sz = size();
+    if (__pos > __sz)
+        __throw_out_of_range();
+    size_type __cap = capacity();
+    if (__libcpp_is_constant_evaluated()) {
+        if (__cap - __sz >= __n)
+            __grow_by_and_replace(__cap, 0, __sz, __pos, 0, __n, __s);
+        else
+            __grow_by_and_replace(__cap, __sz + __n - __cap, __sz, __pos, 0, __n, __s);
+        return *this;
+    }
+    if (__cap - __sz >= __n)
+    {
+        if (__n)
+        {
+            value_type* __p = std::__to_address(__get_pointer());
+            size_type __n_move = __sz - __pos;
+            if (__n_move != 0)
+            {
+                if (__p + __pos <= __s && __s < __p + __sz)
+                    __s += __n;
+                traits_type::move(__p + __pos + __n, __p + __pos, __n_move);
+            }
+            traits_type::move(__p + __pos, __s, __n);
+            __sz += __n;
+            __set_size(__sz);
+            traits_type::assign(__p[__sz], value_type());
+        }
+    }
+    else
+        __grow_by_and_replace(__cap, __sz + __n - __cap, __sz, __pos, 0, __n, __s);
+    return *this;
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+_LIBCPP_CONSTEXPR_SINCE_CXX20
+basic_string<_CharT, _Traits, _Allocator>&
+basic_string<_CharT, _Traits, _Allocator>::insert(size_type __pos, size_type __n, value_type __c)
+{
+    size_type __sz = size();
+    if (__pos > __sz)
+        __throw_out_of_range();
+    if (__n)
+    {
+        size_type __cap = capacity();
+        value_type* __p;
+        if (__cap - __sz >= __n)
+        {
+            __p = std::__to_address(__get_pointer());
+            size_type __n_move = __sz - __pos;
+            if (__n_move != 0)
+                traits_type::move(__p + __pos + __n, __p + __pos, __n_move);
+        }
+        else
+        {
+            __grow_by_without_replace(__cap, __sz + __n - __cap, __sz, __pos, 0, __n);
+            __p = std::__to_address(__get_long_pointer());
+        }
+        traits_type::assign(__p + __pos, __n, __c);
+        __sz += __n;
+        __set_size(__sz);
+        traits_type::assign(__p[__sz], value_type());
+    }
+    return *this;
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+template<class _InputIterator, __enable_if_t<__has_exactly_input_iterator_category<_InputIterator>::value, int> >
+_LIBCPP_CONSTEXPR_SINCE_CXX20 typename basic_string<_CharT, _Traits, _Allocator>::iterator
+basic_string<_CharT, _Traits, _Allocator>::insert(const_iterator __pos, _InputIterator __first, _InputIterator __last)
+{
+  const basic_string __temp(__first, __last, __alloc());
+  return insert(__pos, __temp.data(), __temp.data() + __temp.size());
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+template<class _ForwardIterator, __enable_if_t<__has_forward_iterator_category<_ForwardIterator>::value, int> >
+_LIBCPP_CONSTEXPR_SINCE_CXX20 typename basic_string<_CharT, _Traits, _Allocator>::iterator
+basic_string<_CharT, _Traits, _Allocator>::insert(const_iterator __pos, _ForwardIterator __first, _ForwardIterator __last)
+{
+    auto __n = static_cast<size_type>(std::distance(__first, __last));
+    return __insert_with_size(__pos, __first, __last, __n);
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+template<class _Iterator, class _Sentinel>
+_LIBCPP_CONSTEXPR_SINCE_CXX20
+typename basic_string<_CharT, _Traits, _Allocator>::iterator
+basic_string<_CharT, _Traits, _Allocator>::__insert_with_size(
+    const_iterator __pos, _Iterator __first, _Sentinel __last, size_type __n) {
+    size_type __ip = static_cast<size_type>(__pos - begin());
+    if (__n == 0)
+        return begin() + __ip;
+
+    if (__string_is_trivial_iterator<_Iterator>::value && !__addr_in_range(*__first))
+    {
+        return __insert_from_safe_copy(__n, __ip, __first, __last);
+    }
+    else
+    {
+        const basic_string __temp(__init_with_sentinel_tag(), __first, __last, __alloc());
+        return __insert_from_safe_copy(__n, __ip, __temp.begin(), __temp.end());
+    }
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+_LIBCPP_CONSTEXPR_SINCE_CXX20
+basic_string<_CharT, _Traits, _Allocator>&
+basic_string<_CharT, _Traits, _Allocator>::insert(size_type __pos1, const basic_string& __str,
+                                                  size_type __pos2, size_type __n)
+{
+    size_type __str_sz = __str.size();
+    if (__pos2 > __str_sz)
+        __throw_out_of_range();
+    return insert(__pos1, __str.data() + __pos2, std::min(__n, __str_sz - __pos2));
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+template <class _Tp,
+          __enable_if_t<__can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value &&
+                            !__is_same_uncvref<_Tp, basic_string<_CharT, _Traits, _Allocator> >::value,
+                        int> >
+_LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string<_CharT, _Traits, _Allocator>&
+basic_string<_CharT, _Traits, _Allocator>::insert(size_type __pos1, const _Tp& __t, size_type __pos2, size_type __n) {
+    __self_view __sv = __t;
+    size_type __str_sz = __sv.size();
+    if (__pos2 > __str_sz)
+        __throw_out_of_range();
+    return insert(__pos1, __sv.data() + __pos2, std::min(__n, __str_sz - __pos2));
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+_LIBCPP_CONSTEXPR_SINCE_CXX20
+basic_string<_CharT, _Traits, _Allocator>&
+basic_string<_CharT, _Traits, _Allocator>::insert(size_type __pos, const value_type* __s)
+{
+    _LIBCPP_ASSERT_UNCATEGORIZED(__s != nullptr, "string::insert received nullptr");
+    return insert(__pos, __s, traits_type::length(__s));
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+_LIBCPP_CONSTEXPR_SINCE_CXX20
+typename basic_string<_CharT, _Traits, _Allocator>::iterator
+basic_string<_CharT, _Traits, _Allocator>::insert(const_iterator __pos, value_type __c)
+{
+    size_type __ip = static_cast<size_type>(__pos - begin());
+    size_type __sz = size();
+    size_type __cap = capacity();
+    value_type* __p;
+    if (__cap == __sz)
+    {
+        __grow_by_without_replace(__cap, 1, __sz, __ip, 0, 1);
+        __p = std::__to_address(__get_long_pointer());
+    }
+    else
+    {
+        __p = std::__to_address(__get_pointer());
+        size_type __n_move = __sz - __ip;
+        if (__n_move != 0)
+            traits_type::move(__p + __ip + 1, __p + __ip, __n_move);
+    }
+    traits_type::assign(__p[__ip], __c);
+    traits_type::assign(__p[++__sz], value_type());
+    __set_size(__sz);
+    return begin() + static_cast<difference_type>(__ip);
+}
+
+// replace
+
+template <class _CharT, class _Traits, class _Allocator>
+_LIBCPP_CONSTEXPR_SINCE_CXX20
+basic_string<_CharT, _Traits, _Allocator>&
+basic_string<_CharT, _Traits, _Allocator>::replace(size_type __pos, size_type __n1, const value_type* __s, size_type __n2)
+    _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
+{
+    _LIBCPP_ASSERT_UNCATEGORIZED(__n2 == 0 || __s != nullptr, "string::replace received nullptr");
+    size_type __sz = size();
+    if (__pos > __sz)
+        __throw_out_of_range();
+    __n1 = std::min(__n1, __sz - __pos);
+    size_type __cap = capacity();
+    if (__cap - __sz + __n1 >= __n2)
+    {
+        value_type* __p = std::__to_address(__get_pointer());
+        if (__n1 != __n2)
+        {
+            size_type __n_move = __sz - __pos - __n1;
+            if (__n_move != 0)
+            {
+                if (__n1 > __n2)
+                {
+                    traits_type::move(__p + __pos, __s, __n2);
+                    traits_type::move(__p + __pos + __n2, __p + __pos + __n1, __n_move);
+                    return __null_terminate_at(__p, __sz + (__n2 - __n1));
+                }
+                if (std::__is_pointer_in_range(__p + __pos + 1, __p + __sz, __s))
+                {
+                    if (__p + __pos + __n1 <= __s)
+                        __s += __n2 - __n1;
+                    else // __p + __pos < __s < __p + __pos + __n1
+                    {
+                        traits_type::move(__p + __pos, __s, __n1);
+                        __pos += __n1;
+                        __s += __n2;
+                        __n2 -= __n1;
+                        __n1 = 0;
+                    }
+                }
+                traits_type::move(__p + __pos + __n2, __p + __pos + __n1, __n_move);
+            }
+        }
+        traits_type::move(__p + __pos, __s, __n2);
+        return __null_terminate_at(__p, __sz + (__n2 - __n1));
+    }
+    else
+        __grow_by_and_replace(__cap, __sz - __n1 + __n2 - __cap, __sz, __pos, __n1, __n2, __s);
+    return *this;
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+_LIBCPP_CONSTEXPR_SINCE_CXX20
+basic_string<_CharT, _Traits, _Allocator>&
+basic_string<_CharT, _Traits, _Allocator>::replace(size_type __pos, size_type __n1, size_type __n2, value_type __c)
+{
+    size_type __sz = size();
+    if (__pos > __sz)
+        __throw_out_of_range();
+    __n1 = std::min(__n1, __sz - __pos);
+    size_type __cap = capacity();
+    value_type* __p;
+    if (__cap - __sz + __n1 >= __n2)
+    {
+        __p = std::__to_address(__get_pointer());
+        if (__n1 != __n2)
+        {
+            size_type __n_move = __sz - __pos - __n1;
+            if (__n_move != 0)
+                traits_type::move(__p + __pos + __n2, __p + __pos + __n1, __n_move);
+        }
+    }
+    else
+    {
+        __grow_by_without_replace(__cap, __sz - __n1 + __n2 - __cap, __sz, __pos, __n1, __n2);
+        __p = std::__to_address(__get_long_pointer());
+    }
+    traits_type::assign(__p + __pos, __n2, __c);
+    return __null_terminate_at(__p, __sz - (__n1 - __n2));
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+template<class _InputIterator, __enable_if_t<__has_input_iterator_category<_InputIterator>::value, int> >
+_LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string<_CharT, _Traits, _Allocator>&
+basic_string<_CharT, _Traits, _Allocator>::replace(const_iterator __i1, const_iterator __i2,
+                                                   _InputIterator __j1, _InputIterator __j2)
+{
+    const basic_string __temp(__j1, __j2, __alloc());
+    return replace(__i1, __i2, __temp);
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+_LIBCPP_CONSTEXPR_SINCE_CXX20
+basic_string<_CharT, _Traits, _Allocator>&
+basic_string<_CharT, _Traits, _Allocator>::replace(size_type __pos1, size_type __n1, const basic_string& __str,
+                                                   size_type __pos2, size_type __n2)
+{
+    size_type __str_sz = __str.size();
+    if (__pos2 > __str_sz)
+        __throw_out_of_range();
+    return replace(__pos1, __n1, __str.data() + __pos2, std::min(__n2, __str_sz - __pos2));
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+template <class _Tp,
+          __enable_if_t<__can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value &&
+                            !__is_same_uncvref<_Tp, basic_string<_CharT, _Traits, _Allocator> >::value,
+                        int> >
+_LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string<_CharT, _Traits, _Allocator>&
+basic_string<_CharT, _Traits, _Allocator>::replace(
+    size_type __pos1, size_type __n1, const _Tp& __t, size_type __pos2, size_type __n2) {
+    __self_view __sv = __t;
+    size_type __str_sz = __sv.size();
+    if (__pos2 > __str_sz)
+        __throw_out_of_range();
+    return replace(__pos1, __n1, __sv.data() + __pos2, std::min(__n2, __str_sz - __pos2));
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+_LIBCPP_CONSTEXPR_SINCE_CXX20
+basic_string<_CharT, _Traits, _Allocator>&
+basic_string<_CharT, _Traits, _Allocator>::replace(size_type __pos, size_type __n1, const value_type* __s)
+{
+    _LIBCPP_ASSERT_UNCATEGORIZED(__s != nullptr, "string::replace received nullptr");
+    return replace(__pos, __n1, __s, traits_type::length(__s));
+}
+
+// erase
+
+// 'externally instantiated' erase() implementation, called when __n != npos.
+// Does not check __pos against size()
+template <class _CharT, class _Traits, class _Allocator>
+_LIBCPP_CONSTEXPR_SINCE_CXX20
+void
+basic_string<_CharT, _Traits, _Allocator>::__erase_external_with_move(
+    size_type __pos, size_type __n)
+{
+    if (__n)
+    {
+        size_type __sz = size();
+        value_type* __p = std::__to_address(__get_pointer());
+        __n = std::min(__n, __sz - __pos);
+        size_type __n_move = __sz - __pos - __n;
+        if (__n_move != 0)
+            traits_type::move(__p + __pos, __p + __pos + __n, __n_move);
+        __null_terminate_at(__p, __sz - __n);
+    }
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+_LIBCPP_CONSTEXPR_SINCE_CXX20
+basic_string<_CharT, _Traits, _Allocator>&
+basic_string<_CharT, _Traits, _Allocator>::erase(size_type __pos,
+                                                 size_type __n) {
+  if (__pos > size())
+    __throw_out_of_range();
+  if (__n == npos) {
+    __erase_to_end(__pos);
+  } else {
+    __erase_external_with_move(__pos, __n);
+  }
+  return *this;
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_CONSTEXPR_SINCE_CXX20
+typename basic_string<_CharT, _Traits, _Allocator>::iterator
+basic_string<_CharT, _Traits, _Allocator>::erase(const_iterator __pos)
+{
+  _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(
+      __pos != end(), "string::erase(iterator) called with a non-dereferenceable iterator");
+  iterator __b = begin();
+  size_type __r = static_cast<size_type>(__pos - __b);
+  erase(__r, 1);
+  return __b + static_cast<difference_type>(__r);
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_CONSTEXPR_SINCE_CXX20
+typename basic_string<_CharT, _Traits, _Allocator>::iterator
+basic_string<_CharT, _Traits, _Allocator>::erase(const_iterator __first, const_iterator __last)
+{
+  _LIBCPP_ASSERT_VALID_INPUT_RANGE(__first <= __last, "string::erase(first, last) called with invalid range");
+  iterator __b = begin();
+  size_type __r = static_cast<size_type>(__first - __b);
+  erase(__r, static_cast<size_type>(__last - __first));
+  return __b + static_cast<difference_type>(__r);
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_CONSTEXPR_SINCE_CXX20
+void
+basic_string<_CharT, _Traits, _Allocator>::pop_back()
+{
+    _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(!empty(), "string::pop_back(): string is already empty");
+    __erase_to_end(size() - 1);
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_CONSTEXPR_SINCE_CXX20
+void
+basic_string<_CharT, _Traits, _Allocator>::clear() _NOEXCEPT
+{
+    if (__is_long())
+    {
+        traits_type::assign(*__get_long_pointer(), value_type());
+        __set_long_size(0);
+    }
+    else
+    {
+        traits_type::assign(*__get_short_pointer(), value_type());
+        __set_short_size(0);
+    }
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+_LIBCPP_CONSTEXPR_SINCE_CXX20
+void
+basic_string<_CharT, _Traits, _Allocator>::resize(size_type __n, value_type __c)
+{
+    size_type __sz = size();
+    if (__n > __sz)
+        append(__n - __sz, __c);
+    else
+        __erase_to_end(__n);
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+_LIBCPP_CONSTEXPR_SINCE_CXX20 inline void
+basic_string<_CharT, _Traits, _Allocator>::__resize_default_init(size_type __n)
+{
+    size_type __sz = size();
+    if (__n > __sz) {
+       __append_default_init(__n - __sz);
+    } else
+        __erase_to_end(__n);
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+_LIBCPP_CONSTEXPR_SINCE_CXX20
+void
+basic_string<_CharT, _Traits, _Allocator>::reserve(size_type __requested_capacity)
+{
+    if (__requested_capacity > max_size())
+        __throw_length_error();
+
+    // Make sure reserve(n) never shrinks. This is technically only required in C++20
+    // and later (since P0966R1), however we provide consistent behavior in all Standard
+    // modes because this function is instantiated in the shared library.
+    if (__requested_capacity <= capacity())
+        return;
+
+    size_type __target_capacity = std::max(__requested_capacity, size());
+    __target_capacity = __recommend(__target_capacity);
+    if (__target_capacity == capacity()) return;
+
+    __shrink_or_extend(__target_capacity);
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_CONSTEXPR_SINCE_CXX20
+void
+basic_string<_CharT, _Traits, _Allocator>::shrink_to_fit() _NOEXCEPT
+{
+    size_type __target_capacity = __recommend(size());
+    if (__target_capacity == capacity()) return;
+
+    __shrink_or_extend(__target_capacity);
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_CONSTEXPR_SINCE_CXX20
+void
+basic_string<_CharT, _Traits, _Allocator>::__shrink_or_extend(size_type __target_capacity)
+{
+    size_type __cap = capacity();
+    size_type __sz = size();
+
+    pointer __new_data, __p;
+    bool __was_long, __now_long;
+    if (__fits_in_sso(__target_capacity))
+    {
+        __was_long = true;
+        __now_long = false;
+        __new_data = __get_short_pointer();
+        __p = __get_long_pointer();
+    }
+    else
+    {
+        if (__target_capacity > __cap) {
+            auto __allocation = std::__allocate_at_least(__alloc(), __target_capacity + 1);
+            __new_data = __allocation.ptr;
+            __target_capacity = __allocation.count - 1;
+        }
+        else
+        {
+        #ifndef _LIBCPP_HAS_NO_EXCEPTIONS
+            try
+            {
+        #endif // _LIBCPP_HAS_NO_EXCEPTIONS
+                auto __allocation = std::__allocate_at_least(__alloc(), __target_capacity + 1);
+                __new_data = __allocation.ptr;
+                __target_capacity = __allocation.count - 1;
+        #ifndef _LIBCPP_HAS_NO_EXCEPTIONS
+            }
+            catch (...)
+            {
+                return;
+            }
+        #else  // _LIBCPP_HAS_NO_EXCEPTIONS
+            if (__new_data == nullptr)
+                return;
+        #endif // _LIBCPP_HAS_NO_EXCEPTIONS
+        }
+        __begin_lifetime(__new_data, __target_capacity + 1);
+        __now_long = true;
+        __was_long = __is_long();
+        __p = __get_pointer();
+    }
+    traits_type::copy(std::__to_address(__new_data),
+                      std::__to_address(__p), size()+1);
+    if (__was_long)
+        __alloc_traits::deallocate(__alloc(), __p, __cap+1);
+    if (__now_long)
+    {
+        __set_long_cap(__target_capacity+1);
+        __set_long_size(__sz);
+        __set_long_pointer(__new_data);
+    }
+    else
+        __set_short_size(__sz);
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+_LIBCPP_CONSTEXPR_SINCE_CXX20
+typename basic_string<_CharT, _Traits, _Allocator>::const_reference
+basic_string<_CharT, _Traits, _Allocator>::at(size_type __n) const
+{
+    if (__n >= size())
+        __throw_out_of_range();
+    return (*this)[__n];
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+_LIBCPP_CONSTEXPR_SINCE_CXX20
+typename basic_string<_CharT, _Traits, _Allocator>::reference
+basic_string<_CharT, _Traits, _Allocator>::at(size_type __n)
+{
+    if (__n >= size())
+        __throw_out_of_range();
+    return (*this)[__n];
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+_LIBCPP_CONSTEXPR_SINCE_CXX20
+typename basic_string<_CharT, _Traits, _Allocator>::size_type
+basic_string<_CharT, _Traits, _Allocator>::copy(value_type* __s, size_type __n, size_type __pos) const
+{
+    size_type __sz = size();
+    if (__pos > __sz)
+        __throw_out_of_range();
+    size_type __rlen = std::min(__n, __sz - __pos);
+    traits_type::copy(__s, data() + __pos, __rlen);
+    return __rlen;
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_CONSTEXPR_SINCE_CXX20
+void
+basic_string<_CharT, _Traits, _Allocator>::swap(basic_string& __str)
+#if _LIBCPP_STD_VER >= 14
+        _NOEXCEPT
+#else
+        _NOEXCEPT_(!__alloc_traits::propagate_on_container_swap::value ||
+                    __is_nothrow_swappable<allocator_type>::value)
+#endif
+{
+    _LIBCPP_ASSERT_COMPATIBLE_ALLOCATOR(
+        __alloc_traits::propagate_on_container_swap::value ||
+        __alloc_traits::is_always_equal::value ||
+        __alloc() == __str.__alloc(), "swapping non-equal allocators");
+    std::swap(__r_.first(), __str.__r_.first());
+    std::__swap_allocator(__alloc(), __str.__alloc());
+}
+
+// find
+
+template <class _Traits>
+struct _LIBCPP_HIDDEN __traits_eq
+{
+    typedef typename _Traits::char_type char_type;
+    _LIBCPP_HIDE_FROM_ABI
+    bool operator()(const char_type& __x, const char_type& __y) _NOEXCEPT
+        {return _Traits::eq(__x, __y);}
+};
+
+template<class _CharT, class _Traits, class _Allocator>
+_LIBCPP_CONSTEXPR_SINCE_CXX20
+typename basic_string<_CharT, _Traits, _Allocator>::size_type
+basic_string<_CharT, _Traits, _Allocator>::find(const value_type* __s,
+                                                size_type __pos,
+                                                size_type __n) const _NOEXCEPT
+{
+    _LIBCPP_ASSERT_UNCATEGORIZED(__n == 0 || __s != nullptr, "string::find(): received nullptr");
+    return std::__str_find<value_type, size_type, traits_type, npos>
+        (data(), size(), __s, __pos, __n);
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_CONSTEXPR_SINCE_CXX20
+typename basic_string<_CharT, _Traits, _Allocator>::size_type
+basic_string<_CharT, _Traits, _Allocator>::find(const basic_string& __str,
+                                                size_type __pos) const _NOEXCEPT
+{
+    return std::__str_find<value_type, size_type, traits_type, npos>
+        (data(), size(), __str.data(), __pos, __str.size());
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+template <class _Tp, __enable_if_t<__can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value, int> >
+_LIBCPP_CONSTEXPR_SINCE_CXX20 typename basic_string<_CharT, _Traits, _Allocator>::size_type
+basic_string<_CharT, _Traits, _Allocator>::find(const _Tp &__t,
+                                                size_type __pos) const _NOEXCEPT
+{
+    __self_view __sv = __t;
+    return std::__str_find<value_type, size_type, traits_type, npos>
+        (data(), size(), __sv.data(), __pos, __sv.size());
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_CONSTEXPR_SINCE_CXX20
+typename basic_string<_CharT, _Traits, _Allocator>::size_type
+basic_string<_CharT, _Traits, _Allocator>::find(const value_type* __s,
+                                                size_type __pos) const _NOEXCEPT
+{
+    _LIBCPP_ASSERT_UNCATEGORIZED(__s != nullptr, "string::find(): received nullptr");
+    return std::__str_find<value_type, size_type, traits_type, npos>
+        (data(), size(), __s, __pos, traits_type::length(__s));
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+_LIBCPP_CONSTEXPR_SINCE_CXX20
+typename basic_string<_CharT, _Traits, _Allocator>::size_type
+basic_string<_CharT, _Traits, _Allocator>::find(value_type __c,
+                                                size_type __pos) const _NOEXCEPT
+{
+    return std::__str_find<value_type, size_type, traits_type, npos>
+        (data(), size(), __c, __pos);
+}
+
+// rfind
+
+template<class _CharT, class _Traits, class _Allocator>
+_LIBCPP_CONSTEXPR_SINCE_CXX20
+typename basic_string<_CharT, _Traits, _Allocator>::size_type
+basic_string<_CharT, _Traits, _Allocator>::rfind(const value_type* __s,
+                                                 size_type __pos,
+                                                 size_type __n) const _NOEXCEPT
+{
+    _LIBCPP_ASSERT_UNCATEGORIZED(__n == 0 || __s != nullptr, "string::rfind(): received nullptr");
+    return std::__str_rfind<value_type, size_type, traits_type, npos>
+        (data(), size(), __s, __pos, __n);
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_CONSTEXPR_SINCE_CXX20
+typename basic_string<_CharT, _Traits, _Allocator>::size_type
+basic_string<_CharT, _Traits, _Allocator>::rfind(const basic_string& __str,
+                                                 size_type __pos) const _NOEXCEPT
+{
+    return std::__str_rfind<value_type, size_type, traits_type, npos>
+        (data(), size(), __str.data(), __pos, __str.size());
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+template <class _Tp, __enable_if_t<__can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value, int> >
+_LIBCPP_CONSTEXPR_SINCE_CXX20 typename basic_string<_CharT, _Traits, _Allocator>::size_type
+basic_string<_CharT, _Traits, _Allocator>::rfind(const _Tp& __t,
+                                                size_type __pos) const _NOEXCEPT
+{
+    __self_view __sv = __t;
+    return std::__str_rfind<value_type, size_type, traits_type, npos>
+        (data(), size(), __sv.data(), __pos, __sv.size());
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_CONSTEXPR_SINCE_CXX20
+typename basic_string<_CharT, _Traits, _Allocator>::size_type
+basic_string<_CharT, _Traits, _Allocator>::rfind(const value_type* __s,
+                                                 size_type __pos) const _NOEXCEPT
+{
+    _LIBCPP_ASSERT_UNCATEGORIZED(__s != nullptr, "string::rfind(): received nullptr");
+    return std::__str_rfind<value_type, size_type, traits_type, npos>
+        (data(), size(), __s, __pos, traits_type::length(__s));
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+_LIBCPP_CONSTEXPR_SINCE_CXX20
+typename basic_string<_CharT, _Traits, _Allocator>::size_type
+basic_string<_CharT, _Traits, _Allocator>::rfind(value_type __c,
+                                                 size_type __pos) const _NOEXCEPT
+{
+    return std::__str_rfind<value_type, size_type, traits_type, npos>
+        (data(), size(), __c, __pos);
+}
+
+// find_first_of
+
+template<class _CharT, class _Traits, class _Allocator>
+_LIBCPP_CONSTEXPR_SINCE_CXX20
+typename basic_string<_CharT, _Traits, _Allocator>::size_type
+basic_string<_CharT, _Traits, _Allocator>::find_first_of(const value_type* __s,
+                                                         size_type __pos,
+                                                         size_type __n) const _NOEXCEPT
+{
+    _LIBCPP_ASSERT_UNCATEGORIZED(__n == 0 || __s != nullptr, "string::find_first_of(): received nullptr");
+    return std::__str_find_first_of<value_type, size_type, traits_type, npos>
+        (data(), size(), __s, __pos, __n);
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_CONSTEXPR_SINCE_CXX20
+typename basic_string<_CharT, _Traits, _Allocator>::size_type
+basic_string<_CharT, _Traits, _Allocator>::find_first_of(const basic_string& __str,
+                                                         size_type __pos) const _NOEXCEPT
+{
+    return std::__str_find_first_of<value_type, size_type, traits_type, npos>
+        (data(), size(), __str.data(), __pos, __str.size());
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+template <class _Tp, __enable_if_t<__can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value, int> >
+_LIBCPP_CONSTEXPR_SINCE_CXX20 typename basic_string<_CharT, _Traits, _Allocator>::size_type
+basic_string<_CharT, _Traits, _Allocator>::find_first_of(const _Tp& __t,
+                                                size_type __pos) const _NOEXCEPT
+{
+    __self_view __sv = __t;
+    return std::__str_find_first_of<value_type, size_type, traits_type, npos>
+        (data(), size(), __sv.data(), __pos, __sv.size());
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_CONSTEXPR_SINCE_CXX20
+typename basic_string<_CharT, _Traits, _Allocator>::size_type
+basic_string<_CharT, _Traits, _Allocator>::find_first_of(const value_type* __s,
+                                                         size_type __pos) const _NOEXCEPT
+{
+    _LIBCPP_ASSERT_UNCATEGORIZED(__s != nullptr, "string::find_first_of(): received nullptr");
+    return std::__str_find_first_of<value_type, size_type, traits_type, npos>
+        (data(), size(), __s, __pos, traits_type::length(__s));
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_CONSTEXPR_SINCE_CXX20
+typename basic_string<_CharT, _Traits, _Allocator>::size_type
+basic_string<_CharT, _Traits, _Allocator>::find_first_of(value_type __c,
+                                                         size_type __pos) const _NOEXCEPT
+{
+    return find(__c, __pos);
+}
+
+// find_last_of
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_CONSTEXPR_SINCE_CXX20
+typename basic_string<_CharT, _Traits, _Allocator>::size_type
+basic_string<_CharT, _Traits, _Allocator>::find_last_of(const value_type* __s,
+                                                        size_type __pos,
+                                                        size_type __n) const _NOEXCEPT
+{
+    _LIBCPP_ASSERT_UNCATEGORIZED(__n == 0 || __s != nullptr, "string::find_last_of(): received nullptr");
+    return std::__str_find_last_of<value_type, size_type, traits_type, npos>
+        (data(), size(), __s, __pos, __n);
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_CONSTEXPR_SINCE_CXX20
+typename basic_string<_CharT, _Traits, _Allocator>::size_type
+basic_string<_CharT, _Traits, _Allocator>::find_last_of(const basic_string& __str,
+                                                        size_type __pos) const _NOEXCEPT
+{
+    return std::__str_find_last_of<value_type, size_type, traits_type, npos>
+        (data(), size(), __str.data(), __pos, __str.size());
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+template <class _Tp, __enable_if_t<__can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value, int> >
+_LIBCPP_CONSTEXPR_SINCE_CXX20 typename basic_string<_CharT, _Traits, _Allocator>::size_type
+basic_string<_CharT, _Traits, _Allocator>::find_last_of(const _Tp& __t,
+                                                size_type __pos) const _NOEXCEPT
+{
+    __self_view __sv = __t;
+    return std::__str_find_last_of<value_type, size_type, traits_type, npos>
+        (data(), size(), __sv.data(), __pos, __sv.size());
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_CONSTEXPR_SINCE_CXX20
+typename basic_string<_CharT, _Traits, _Allocator>::size_type
+basic_string<_CharT, _Traits, _Allocator>::find_last_of(const value_type* __s,
+                                                        size_type __pos) const _NOEXCEPT
+{
+    _LIBCPP_ASSERT_UNCATEGORIZED(__s != nullptr, "string::find_last_of(): received nullptr");
+    return std::__str_find_last_of<value_type, size_type, traits_type, npos>
+        (data(), size(), __s, __pos, traits_type::length(__s));
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_CONSTEXPR_SINCE_CXX20
+typename basic_string<_CharT, _Traits, _Allocator>::size_type
+basic_string<_CharT, _Traits, _Allocator>::find_last_of(value_type __c,
+                                                        size_type __pos) const _NOEXCEPT
+{
+    return rfind(__c, __pos);
+}
+
+// find_first_not_of
+
+template<class _CharT, class _Traits, class _Allocator>
+_LIBCPP_CONSTEXPR_SINCE_CXX20
+typename basic_string<_CharT, _Traits, _Allocator>::size_type
+basic_string<_CharT, _Traits, _Allocator>::find_first_not_of(const value_type* __s,
+                                                             size_type __pos,
+                                                             size_type __n) const _NOEXCEPT
+{
+    _LIBCPP_ASSERT_UNCATEGORIZED(__n == 0 || __s != nullptr, "string::find_first_not_of(): received nullptr");
+    return std::__str_find_first_not_of<value_type, size_type, traits_type, npos>
+        (data(), size(), __s, __pos, __n);
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_CONSTEXPR_SINCE_CXX20
+typename basic_string<_CharT, _Traits, _Allocator>::size_type
+basic_string<_CharT, _Traits, _Allocator>::find_first_not_of(const basic_string& __str,
+                                                             size_type __pos) const _NOEXCEPT
+{
+    return std::__str_find_first_not_of<value_type, size_type, traits_type, npos>
+        (data(), size(), __str.data(), __pos, __str.size());
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+template <class _Tp, __enable_if_t<__can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value, int> >
+_LIBCPP_CONSTEXPR_SINCE_CXX20 typename basic_string<_CharT, _Traits, _Allocator>::size_type
+basic_string<_CharT, _Traits, _Allocator>::find_first_not_of(const _Tp& __t,
+                                                size_type __pos) const _NOEXCEPT
+{
+    __self_view __sv = __t;
+    return std::__str_find_first_not_of<value_type, size_type, traits_type, npos>
+        (data(), size(), __sv.data(), __pos, __sv.size());
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_CONSTEXPR_SINCE_CXX20
+typename basic_string<_CharT, _Traits, _Allocator>::size_type
+basic_string<_CharT, _Traits, _Allocator>::find_first_not_of(const value_type* __s,
+                                                             size_type __pos) const _NOEXCEPT
+{
+    _LIBCPP_ASSERT_UNCATEGORIZED(__s != nullptr, "string::find_first_not_of(): received nullptr");
+    return std::__str_find_first_not_of<value_type, size_type, traits_type, npos>
+        (data(), size(), __s, __pos, traits_type::length(__s));
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_CONSTEXPR_SINCE_CXX20
+typename basic_string<_CharT, _Traits, _Allocator>::size_type
+basic_string<_CharT, _Traits, _Allocator>::find_first_not_of(value_type __c,
+                                                             size_type __pos) const _NOEXCEPT
+{
+    return std::__str_find_first_not_of<value_type, size_type, traits_type, npos>
+        (data(), size(), __c, __pos);
+}
+
+// find_last_not_of
+
+template<class _CharT, class _Traits, class _Allocator>
+_LIBCPP_CONSTEXPR_SINCE_CXX20
+typename basic_string<_CharT, _Traits, _Allocator>::size_type
+basic_string<_CharT, _Traits, _Allocator>::find_last_not_of(const value_type* __s,
+                                                            size_type __pos,
+                                                            size_type __n) const _NOEXCEPT
+{
+    _LIBCPP_ASSERT_UNCATEGORIZED(__n == 0 || __s != nullptr, "string::find_last_not_of(): received nullptr");
+    return std::__str_find_last_not_of<value_type, size_type, traits_type, npos>
+        (data(), size(), __s, __pos, __n);
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_CONSTEXPR_SINCE_CXX20
+typename basic_string<_CharT, _Traits, _Allocator>::size_type
+basic_string<_CharT, _Traits, _Allocator>::find_last_not_of(const basic_string& __str,
+                                                            size_type __pos) const _NOEXCEPT
+{
+    return std::__str_find_last_not_of<value_type, size_type, traits_type, npos>
+        (data(), size(), __str.data(), __pos, __str.size());
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+template <class _Tp, __enable_if_t<__can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value, int> >
+_LIBCPP_CONSTEXPR_SINCE_CXX20 typename basic_string<_CharT, _Traits, _Allocator>::size_type
+basic_string<_CharT, _Traits, _Allocator>::find_last_not_of(const _Tp& __t,
+                                                size_type __pos) const _NOEXCEPT
+{
+    __self_view __sv = __t;
+    return std::__str_find_last_not_of<value_type, size_type, traits_type, npos>
+        (data(), size(), __sv.data(), __pos, __sv.size());
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_CONSTEXPR_SINCE_CXX20
+typename basic_string<_CharT, _Traits, _Allocator>::size_type
+basic_string<_CharT, _Traits, _Allocator>::find_last_not_of(const value_type* __s,
+                                                            size_type __pos) const _NOEXCEPT
+{
+    _LIBCPP_ASSERT_UNCATEGORIZED(__s != nullptr, "string::find_last_not_of(): received nullptr");
+    return std::__str_find_last_not_of<value_type, size_type, traits_type, npos>
+        (data(), size(), __s, __pos, traits_type::length(__s));
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_CONSTEXPR_SINCE_CXX20
+typename basic_string<_CharT, _Traits, _Allocator>::size_type
+basic_string<_CharT, _Traits, _Allocator>::find_last_not_of(value_type __c,
+                                                            size_type __pos) const _NOEXCEPT
+{
+    return std::__str_find_last_not_of<value_type, size_type, traits_type, npos>
+        (data(), size(), __c, __pos);
+}
+
+// compare
+
+template <class _CharT, class _Traits, class _Allocator>
+template <class _Tp, __enable_if_t<__can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value, int> >
+_LIBCPP_CONSTEXPR_SINCE_CXX20 int
+basic_string<_CharT, _Traits, _Allocator>::compare(const _Tp& __t) const _NOEXCEPT
+{
+    __self_view __sv = __t;
+    size_t __lhs_sz = size();
+    size_t __rhs_sz = __sv.size();
+    int __result = traits_type::compare(data(), __sv.data(),
+                                        std::min(__lhs_sz, __rhs_sz));
+    if (__result != 0)
+        return __result;
+    if (__lhs_sz < __rhs_sz)
+        return -1;
+    if (__lhs_sz > __rhs_sz)
+        return 1;
+    return 0;
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_CONSTEXPR_SINCE_CXX20
+int
+basic_string<_CharT, _Traits, _Allocator>::compare(const basic_string& __str) const _NOEXCEPT
+{
+    return compare(__self_view(__str));
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_CONSTEXPR_SINCE_CXX20
+int
+basic_string<_CharT, _Traits, _Allocator>::compare(size_type __pos1,
+                                                   size_type __n1,
+                                                   const value_type* __s,
+                                                   size_type __n2) const
+{
+    _LIBCPP_ASSERT_UNCATEGORIZED(__n2 == 0 || __s != nullptr, "string::compare(): received nullptr");
+    size_type __sz = size();
+    if (__pos1 > __sz || __n2 == npos)
+        __throw_out_of_range();
+    size_type __rlen = std::min(__n1, __sz - __pos1);
+    int __r = traits_type::compare(data() + __pos1, __s, std::min(__rlen, __n2));
+    if (__r == 0)
+    {
+        if (__rlen < __n2)
+            __r = -1;
+        else if (__rlen > __n2)
+            __r = 1;
+    }
+    return __r;
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+template <class _Tp, __enable_if_t<__can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value, int> >
+_LIBCPP_CONSTEXPR_SINCE_CXX20 int
+basic_string<_CharT, _Traits, _Allocator>::compare(size_type __pos1,
+                                                   size_type __n1,
+                                                   const _Tp& __t) const
+{
+    __self_view __sv = __t;
+    return compare(__pos1, __n1, __sv.data(), __sv.size());
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_CONSTEXPR_SINCE_CXX20
+int
+basic_string<_CharT, _Traits, _Allocator>::compare(size_type __pos1,
+                                                   size_type __n1,
+                                                   const basic_string& __str) const
+{
+    return compare(__pos1, __n1, __str.data(), __str.size());
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+template <class _Tp,
+          __enable_if_t<__can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value &&
+                            !__is_same_uncvref<_Tp, basic_string<_CharT, _Traits, _Allocator> >::value,
+                        int> >
+_LIBCPP_CONSTEXPR_SINCE_CXX20 int basic_string<_CharT, _Traits, _Allocator>::compare(
+    size_type __pos1, size_type __n1, const _Tp& __t, size_type __pos2, size_type __n2) const {
+    __self_view __sv = __t;
+    return __self_view(*this).substr(__pos1, __n1).compare(__sv.substr(__pos2, __n2));
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+_LIBCPP_CONSTEXPR_SINCE_CXX20
+int
+basic_string<_CharT, _Traits, _Allocator>::compare(size_type __pos1,
+                                                   size_type __n1,
+                                                   const basic_string& __str,
+                                                   size_type __pos2,
+                                                   size_type __n2) const
+{
+    return compare(__pos1, __n1, __self_view(__str), __pos2, __n2);
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+_LIBCPP_CONSTEXPR_SINCE_CXX20
+int
+basic_string<_CharT, _Traits, _Allocator>::compare(const value_type* __s) const _NOEXCEPT
+{
+    _LIBCPP_ASSERT_UNCATEGORIZED(__s != nullptr, "string::compare(): received nullptr");
+    return compare(0, npos, __s, traits_type::length(__s));
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+_LIBCPP_CONSTEXPR_SINCE_CXX20
+int
+basic_string<_CharT, _Traits, _Allocator>::compare(size_type __pos1,
+                                                   size_type __n1,
+                                                   const value_type* __s) const
+{
+    _LIBCPP_ASSERT_UNCATEGORIZED(__s != nullptr, "string::compare(): received nullptr");
+    return compare(__pos1, __n1, __s, traits_type::length(__s));
+}
+
+// __invariants
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_CONSTEXPR_SINCE_CXX20
+bool
+basic_string<_CharT, _Traits, _Allocator>::__invariants() const
+{
+    if (size() > capacity())
+        return false;
+    if (capacity() < __min_cap - 1)
+        return false;
+    if (data() == nullptr)
+        return false;
+    if (!_Traits::eq(data()[size()], value_type()))
+        return false;
+    return true;
+}
+
+// __clear_and_shrink
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_CONSTEXPR_SINCE_CXX20
+void
+basic_string<_CharT, _Traits, _Allocator>::__clear_and_shrink() _NOEXCEPT
+{
+    clear();
+    if(__is_long())
+    {
+        __alloc_traits::deallocate(__alloc(), __get_long_pointer(), capacity() + 1);
+        __default_init();
+    }
+}
+
+// operator==
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI
+bool
+operator==(const basic_string<_CharT, _Traits, _Allocator>& __lhs,
+           const basic_string<_CharT, _Traits, _Allocator>& __rhs) _NOEXCEPT
+{
+#if _LIBCPP_STD_VER >= 20
+    return basic_string_view<_CharT, _Traits>(__lhs) == basic_string_view<_CharT, _Traits>(__rhs);
+#else
+    size_t __lhs_sz = __lhs.size();
+    return __lhs_sz == __rhs.size() && _Traits::compare(__lhs.data(),
+                                                        __rhs.data(),
+                                                        __lhs_sz) == 0;
+#endif
+}
+
+template<class _Allocator>
+inline _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI
+bool
+operator==(const basic_string<char, char_traits<char>, _Allocator>& __lhs,
+           const basic_string<char, char_traits<char>, _Allocator>& __rhs) _NOEXCEPT
+{
+    size_t __lhs_sz = __lhs.size();
+    if (__lhs_sz != __rhs.size())
+        return false;
+    const char* __lp = __lhs.data();
+    const char* __rp = __rhs.data();
+    if (__lhs.__is_long())
+        return char_traits<char>::compare(__lp, __rp, __lhs_sz) == 0;
+    for (; __lhs_sz != 0; --__lhs_sz, ++__lp, ++__rp)
+        if (*__lp != *__rp)
+            return false;
+    return true;
+}
+
+#if _LIBCPP_STD_VER <= 17
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_HIDE_FROM_ABI
+bool
+operator==(const _CharT* __lhs,
+           const basic_string<_CharT, _Traits, _Allocator>& __rhs) _NOEXCEPT
+{
+    typedef basic_string<_CharT, _Traits, _Allocator> _String;
+    _LIBCPP_ASSERT_UNCATEGORIZED(__lhs != nullptr, "operator==(char*, basic_string): received nullptr");
+    size_t __lhs_len = _Traits::length(__lhs);
+    if (__lhs_len != __rhs.size()) return false;
+    return __rhs.compare(0, _String::npos, __lhs, __lhs_len) == 0;
+}
+#endif // _LIBCPP_STD_VER <= 17
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI
+bool
+operator==(const basic_string<_CharT,_Traits,_Allocator>& __lhs,
+           const _CharT* __rhs) _NOEXCEPT
+{
+#if _LIBCPP_STD_VER >= 20
+    return basic_string_view<_CharT, _Traits>(__lhs) == basic_string_view<_CharT, _Traits>(__rhs);
+#else
+    typedef basic_string<_CharT, _Traits, _Allocator> _String;
+    _LIBCPP_ASSERT_UNCATEGORIZED(__rhs != nullptr, "operator==(basic_string, char*): received nullptr");
+    size_t __rhs_len = _Traits::length(__rhs);
+    if (__rhs_len != __lhs.size()) return false;
+    return __lhs.compare(0, _String::npos, __rhs, __rhs_len) == 0;
+#endif
+}
+
+#if _LIBCPP_STD_VER >= 20
+
+template <class _CharT, class _Traits, class _Allocator>
+_LIBCPP_HIDE_FROM_ABI constexpr auto operator<=>(
+    const basic_string<_CharT, _Traits, _Allocator>& __lhs,
+    const basic_string<_CharT, _Traits, _Allocator>& __rhs) noexcept {
+    return basic_string_view<_CharT, _Traits>(__lhs) <=> basic_string_view<_CharT, _Traits>(__rhs);
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+_LIBCPP_HIDE_FROM_ABI constexpr auto
+operator<=>(const basic_string<_CharT, _Traits, _Allocator>& __lhs, const _CharT* __rhs) {
+    return basic_string_view<_CharT, _Traits>(__lhs) <=> basic_string_view<_CharT, _Traits>(__rhs);
+}
+
+#else // _LIBCPP_STD_VER >= 20
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_HIDE_FROM_ABI
+bool
+operator!=(const basic_string<_CharT,_Traits,_Allocator>& __lhs,
+           const basic_string<_CharT, _Traits, _Allocator>& __rhs) _NOEXCEPT
+{
+    return !(__lhs == __rhs);
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_HIDE_FROM_ABI
+bool
+operator!=(const _CharT* __lhs,
+           const basic_string<_CharT, _Traits, _Allocator>& __rhs) _NOEXCEPT
+{
+    return !(__lhs == __rhs);
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_HIDE_FROM_ABI
+bool
+operator!=(const basic_string<_CharT, _Traits, _Allocator>& __lhs,
+           const _CharT* __rhs) _NOEXCEPT
+{
+    return !(__lhs == __rhs);
+}
+
+// operator<
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_HIDE_FROM_ABI
+bool
+operator< (const basic_string<_CharT, _Traits, _Allocator>& __lhs,
+           const basic_string<_CharT, _Traits, _Allocator>& __rhs) _NOEXCEPT
+{
+    return __lhs.compare(__rhs) < 0;
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_HIDE_FROM_ABI
+bool
+operator< (const basic_string<_CharT, _Traits, _Allocator>& __lhs,
+           const _CharT* __rhs) _NOEXCEPT
+{
+    return __lhs.compare(__rhs) < 0;
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_HIDE_FROM_ABI
+bool
+operator< (const _CharT* __lhs,
+           const basic_string<_CharT, _Traits, _Allocator>& __rhs) _NOEXCEPT
+{
+    return __rhs.compare(__lhs) > 0;
+}
+
+// operator>
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_HIDE_FROM_ABI
+bool
+operator> (const basic_string<_CharT, _Traits, _Allocator>& __lhs,
+           const basic_string<_CharT, _Traits, _Allocator>& __rhs) _NOEXCEPT
+{
+    return __rhs < __lhs;
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_HIDE_FROM_ABI
+bool
+operator> (const basic_string<_CharT, _Traits, _Allocator>& __lhs,
+           const _CharT* __rhs) _NOEXCEPT
+{
+    return __rhs < __lhs;
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_HIDE_FROM_ABI
+bool
+operator> (const _CharT* __lhs,
+           const basic_string<_CharT, _Traits, _Allocator>& __rhs) _NOEXCEPT
+{
+    return __rhs < __lhs;
+}
+
+// operator<=
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_HIDE_FROM_ABI
+bool
+operator<=(const basic_string<_CharT, _Traits, _Allocator>& __lhs,
+           const basic_string<_CharT, _Traits, _Allocator>& __rhs) _NOEXCEPT
+{
+    return !(__rhs < __lhs);
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_HIDE_FROM_ABI
+bool
+operator<=(const basic_string<_CharT, _Traits, _Allocator>& __lhs,
+           const _CharT* __rhs) _NOEXCEPT
+{
+    return !(__rhs < __lhs);
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_HIDE_FROM_ABI
+bool
+operator<=(const _CharT* __lhs,
+           const basic_string<_CharT, _Traits, _Allocator>& __rhs) _NOEXCEPT
+{
+    return !(__rhs < __lhs);
+}
+
+// operator>=
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_HIDE_FROM_ABI
+bool
+operator>=(const basic_string<_CharT, _Traits, _Allocator>& __lhs,
+           const basic_string<_CharT, _Traits, _Allocator>& __rhs) _NOEXCEPT
+{
+    return !(__lhs < __rhs);
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_HIDE_FROM_ABI
+bool
+operator>=(const basic_string<_CharT, _Traits, _Allocator>& __lhs,
+           const _CharT* __rhs) _NOEXCEPT
+{
+    return !(__lhs < __rhs);
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_HIDE_FROM_ABI
+bool
+operator>=(const _CharT* __lhs,
+           const basic_string<_CharT, _Traits, _Allocator>& __rhs) _NOEXCEPT
+{
+    return !(__lhs < __rhs);
+}
+#endif // _LIBCPP_STD_VER >= 20
+
+// operator +
+
+template<class _CharT, class _Traits, class _Allocator>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+basic_string<_CharT, _Traits, _Allocator>
+operator+(const basic_string<_CharT, _Traits, _Allocator>& __lhs,
+          const basic_string<_CharT, _Traits, _Allocator>& __rhs)
+{
+    using _String = basic_string<_CharT, _Traits, _Allocator>;
+    auto __lhs_sz = __lhs.size();
+    auto __rhs_sz = __rhs.size();
+    _String __r(__uninitialized_size_tag(),
+                __lhs_sz + __rhs_sz,
+                _String::__alloc_traits::select_on_container_copy_construction(__lhs.get_allocator()));
+    auto __ptr = std::__to_address(__r.__get_pointer());
+    _Traits::copy(__ptr, __lhs.data(), __lhs_sz);
+    _Traits::copy(__ptr + __lhs_sz, __rhs.data(), __rhs_sz);
+    _Traits::assign(__ptr + __lhs_sz + __rhs_sz, 1, _CharT());
+    return __r;
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+_LIBCPP_HIDDEN _LIBCPP_CONSTEXPR_SINCE_CXX20
+basic_string<_CharT, _Traits, _Allocator>
+operator+(const _CharT* __lhs , const basic_string<_CharT,_Traits,_Allocator>& __rhs)
+{
+    using _String = basic_string<_CharT, _Traits, _Allocator>;
+    auto __lhs_sz = _Traits::length(__lhs);
+    auto __rhs_sz = __rhs.size();
+    _String __r(__uninitialized_size_tag(),
+                __lhs_sz + __rhs_sz,
+                _String::__alloc_traits::select_on_container_copy_construction(__rhs.get_allocator()));
+    auto __ptr = std::__to_address(__r.__get_pointer());
+    _Traits::copy(__ptr, __lhs, __lhs_sz);
+    _Traits::copy(__ptr + __lhs_sz, __rhs.data(), __rhs_sz);
+    _Traits::assign(__ptr + __lhs_sz + __rhs_sz, 1, _CharT());
+    return __r;
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+basic_string<_CharT, _Traits, _Allocator>
+operator+(_CharT __lhs, const basic_string<_CharT,_Traits,_Allocator>& __rhs)
+{
+    using _String = basic_string<_CharT, _Traits, _Allocator>;
+    typename _String::size_type __rhs_sz = __rhs.size();
+    _String __r(__uninitialized_size_tag(),
+                __rhs_sz + 1,
+                _String::__alloc_traits::select_on_container_copy_construction(__rhs.get_allocator()));
+    auto __ptr = std::__to_address(__r.__get_pointer());
+    _Traits::assign(__ptr, 1, __lhs);
+    _Traits::copy(__ptr + 1, __rhs.data(), __rhs_sz);
+    _Traits::assign(__ptr + 1 + __rhs_sz, 1, _CharT());
+    return __r;
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_CONSTEXPR_SINCE_CXX20
+basic_string<_CharT, _Traits, _Allocator>
+operator+(const basic_string<_CharT, _Traits, _Allocator>& __lhs, const _CharT* __rhs)
+{
+    using _String = basic_string<_CharT, _Traits, _Allocator>;
+    typename _String::size_type __lhs_sz = __lhs.size();
+    typename _String::size_type __rhs_sz = _Traits::length(__rhs);
+    _String __r(__uninitialized_size_tag(),
+                __lhs_sz + __rhs_sz,
+                _String::__alloc_traits::select_on_container_copy_construction(__lhs.get_allocator()));
+    auto __ptr = std::__to_address(__r.__get_pointer());
+    _Traits::copy(__ptr, __lhs.data(), __lhs_sz);
+    _Traits::copy(__ptr + __lhs_sz, __rhs, __rhs_sz);
+    _Traits::assign(__ptr + __lhs_sz + __rhs_sz, 1, _CharT());
+    return __r;
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+basic_string<_CharT, _Traits, _Allocator>
+operator+(const basic_string<_CharT, _Traits, _Allocator>& __lhs, _CharT __rhs)
+{
+    using _String = basic_string<_CharT, _Traits, _Allocator>;
+    typename _String::size_type __lhs_sz = __lhs.size();
+    _String __r(__uninitialized_size_tag(),
+                __lhs_sz + 1,
+                _String::__alloc_traits::select_on_container_copy_construction(__lhs.get_allocator()));
+    auto __ptr = std::__to_address(__r.__get_pointer());
+    _Traits::copy(__ptr, __lhs.data(), __lhs_sz);
+    _Traits::assign(__ptr + __lhs_sz, 1, __rhs);
+    _Traits::assign(__ptr + 1 + __lhs_sz, 1, _CharT());
+    return __r;
+}
+
+#ifndef _LIBCPP_CXX03_LANG
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+basic_string<_CharT, _Traits, _Allocator>
+operator+(basic_string<_CharT, _Traits, _Allocator>&& __lhs, const basic_string<_CharT, _Traits, _Allocator>& __rhs)
+{
+    return std::move(__lhs.append(__rhs));
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+basic_string<_CharT, _Traits, _Allocator>
+operator+(const basic_string<_CharT, _Traits, _Allocator>& __lhs, basic_string<_CharT, _Traits, _Allocator>&& __rhs)
+{
+    return std::move(__rhs.insert(0, __lhs));
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+basic_string<_CharT, _Traits, _Allocator>
+operator+(basic_string<_CharT, _Traits, _Allocator>&& __lhs, basic_string<_CharT, _Traits, _Allocator>&& __rhs)
+{
+    return std::move(__lhs.append(__rhs));
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+basic_string<_CharT, _Traits, _Allocator>
+operator+(const _CharT* __lhs , basic_string<_CharT,_Traits,_Allocator>&& __rhs)
+{
+    return std::move(__rhs.insert(0, __lhs));
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+basic_string<_CharT, _Traits, _Allocator>
+operator+(_CharT __lhs, basic_string<_CharT,_Traits,_Allocator>&& __rhs)
+{
+    __rhs.insert(__rhs.begin(), __lhs);
+    return std::move(__rhs);
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+basic_string<_CharT, _Traits, _Allocator>
+operator+(basic_string<_CharT, _Traits, _Allocator>&& __lhs, const _CharT* __rhs)
+{
+    return std::move(__lhs.append(__rhs));
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+basic_string<_CharT, _Traits, _Allocator>
+operator+(basic_string<_CharT, _Traits, _Allocator>&& __lhs, _CharT __rhs)
+{
+    __lhs.push_back(__rhs);
+    return std::move(__lhs);
+}
+
+#endif // _LIBCPP_CXX03_LANG
+
+// swap
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+void
+swap(basic_string<_CharT, _Traits, _Allocator>& __lhs,
+     basic_string<_CharT, _Traits, _Allocator>& __rhs)
+     _NOEXCEPT_(_NOEXCEPT_(__lhs.swap(__rhs)))
+{
+    __lhs.swap(__rhs);
+}
+
+_LIBCPP_EXPORTED_FROM_ABI int                stoi  (const string& __str, size_t* __idx = nullptr, int __base = 10);
+_LIBCPP_EXPORTED_FROM_ABI long               stol  (const string& __str, size_t* __idx = nullptr, int __base = 10);
+_LIBCPP_EXPORTED_FROM_ABI unsigned long      stoul (const string& __str, size_t* __idx = nullptr, int __base = 10);
+_LIBCPP_EXPORTED_FROM_ABI long long          stoll (const string& __str, size_t* __idx = nullptr, int __base = 10);
+_LIBCPP_EXPORTED_FROM_ABI unsigned long long stoull(const string& __str, size_t* __idx = nullptr, int __base = 10);
+
+_LIBCPP_EXPORTED_FROM_ABI float       stof (const string& __str, size_t* __idx = nullptr);
+_LIBCPP_EXPORTED_FROM_ABI double      stod (const string& __str, size_t* __idx = nullptr);
+_LIBCPP_EXPORTED_FROM_ABI long double stold(const string& __str, size_t* __idx = nullptr);
+
+_LIBCPP_EXPORTED_FROM_ABI string to_string(int __val);
+_LIBCPP_EXPORTED_FROM_ABI string to_string(unsigned __val);
+_LIBCPP_EXPORTED_FROM_ABI string to_string(long __val);
+_LIBCPP_EXPORTED_FROM_ABI string to_string(unsigned long __val);
+_LIBCPP_EXPORTED_FROM_ABI string to_string(long long __val);
+_LIBCPP_EXPORTED_FROM_ABI string to_string(unsigned long long __val);
+_LIBCPP_EXPORTED_FROM_ABI string to_string(float __val);
+_LIBCPP_EXPORTED_FROM_ABI string to_string(double __val);
+_LIBCPP_EXPORTED_FROM_ABI string to_string(long double __val);
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+_LIBCPP_EXPORTED_FROM_ABI int                stoi  (const wstring& __str, size_t* __idx = nullptr, int __base = 10);
+_LIBCPP_EXPORTED_FROM_ABI long               stol  (const wstring& __str, size_t* __idx = nullptr, int __base = 10);
+_LIBCPP_EXPORTED_FROM_ABI unsigned long      stoul (const wstring& __str, size_t* __idx = nullptr, int __base = 10);
+_LIBCPP_EXPORTED_FROM_ABI long long          stoll (const wstring& __str, size_t* __idx = nullptr, int __base = 10);
+_LIBCPP_EXPORTED_FROM_ABI unsigned long long stoull(const wstring& __str, size_t* __idx = nullptr, int __base = 10);
+
+_LIBCPP_EXPORTED_FROM_ABI float       stof (const wstring& __str, size_t* __idx = nullptr);
+_LIBCPP_EXPORTED_FROM_ABI double      stod (const wstring& __str, size_t* __idx = nullptr);
+_LIBCPP_EXPORTED_FROM_ABI long double stold(const wstring& __str, size_t* __idx = nullptr);
+
+_LIBCPP_EXPORTED_FROM_ABI wstring to_wstring(int __val);
+_LIBCPP_EXPORTED_FROM_ABI wstring to_wstring(unsigned __val);
+_LIBCPP_EXPORTED_FROM_ABI wstring to_wstring(long __val);
+_LIBCPP_EXPORTED_FROM_ABI wstring to_wstring(unsigned long __val);
+_LIBCPP_EXPORTED_FROM_ABI wstring to_wstring(long long __val);
+_LIBCPP_EXPORTED_FROM_ABI wstring to_wstring(unsigned long long __val);
+_LIBCPP_EXPORTED_FROM_ABI wstring to_wstring(float __val);
+_LIBCPP_EXPORTED_FROM_ABI wstring to_wstring(double __val);
+_LIBCPP_EXPORTED_FROM_ABI wstring to_wstring(long double __val);
+#endif // _LIBCPP_HAS_NO_WIDE_CHARACTERS
+
+template<class _CharT, class _Traits, class _Allocator>
+_LIBCPP_TEMPLATE_DATA_VIS
+const typename basic_string<_CharT, _Traits, _Allocator>::size_type
+               basic_string<_CharT, _Traits, _Allocator>::npos;
+
+template <class _CharT, class _Allocator>
+struct __string_hash : public __unary_function<basic_string<_CharT, char_traits<_CharT>, _Allocator>, size_t> {
+    _LIBCPP_HIDE_FROM_ABI size_t
+    operator()(const basic_string<_CharT, char_traits<_CharT>, _Allocator>& __val) const _NOEXCEPT {
+        return std::__do_string_hash(__val.data(), __val.data() + __val.size());
+    }
+};
+
+template <class _Allocator>
+struct hash<basic_string<char, char_traits<char>, _Allocator> > : __string_hash<char, _Allocator> {};
+
+#ifndef _LIBCPP_HAS_NO_CHAR8_T
+template <class _Allocator>
+struct hash<basic_string<char8_t, char_traits<char8_t>, _Allocator> > : __string_hash<char8_t, _Allocator> {};
+#endif
+
+template <class _Allocator>
+struct hash<basic_string<char16_t, char_traits<char16_t>, _Allocator> > : __string_hash<char16_t, _Allocator> {};
+
+template <class _Allocator>
+struct hash<basic_string<char32_t, char_traits<char32_t>, _Allocator> > : __string_hash<char32_t, _Allocator> {};
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+template <class _Allocator>
+struct hash<basic_string<wchar_t, char_traits<wchar_t>, _Allocator> > : __string_hash<wchar_t, _Allocator> {};
+#endif
+
+template<class _CharT, class _Traits, class _Allocator>
+_LIBCPP_HIDE_FROM_ABI basic_ostream<_CharT, _Traits>&
+operator<<(basic_ostream<_CharT, _Traits>& __os,
+           const basic_string<_CharT, _Traits, _Allocator>& __str);
+
+template<class _CharT, class _Traits, class _Allocator>
+_LIBCPP_HIDE_FROM_ABI basic_istream<_CharT, _Traits>&
+operator>>(basic_istream<_CharT, _Traits>& __is,
+           basic_string<_CharT, _Traits, _Allocator>& __str);
+
+template<class _CharT, class _Traits, class _Allocator>
+_LIBCPP_HIDE_FROM_ABI basic_istream<_CharT, _Traits>&
+getline(basic_istream<_CharT, _Traits>& __is,
+        basic_string<_CharT, _Traits, _Allocator>& __str, _CharT __dlm);
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_HIDE_FROM_ABI
+basic_istream<_CharT, _Traits>&
+getline(basic_istream<_CharT, _Traits>& __is,
+        basic_string<_CharT, _Traits, _Allocator>& __str);
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_HIDE_FROM_ABI
+basic_istream<_CharT, _Traits>&
+getline(basic_istream<_CharT, _Traits>&& __is,
+        basic_string<_CharT, _Traits, _Allocator>& __str, _CharT __dlm);
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_HIDE_FROM_ABI
+basic_istream<_CharT, _Traits>&
+getline(basic_istream<_CharT, _Traits>&& __is,
+        basic_string<_CharT, _Traits, _Allocator>& __str);
+
+#if _LIBCPP_STD_VER >= 20
+template <class _CharT, class _Traits, class _Allocator, class _Up>
+inline _LIBCPP_HIDE_FROM_ABI
+    typename basic_string<_CharT, _Traits, _Allocator>::size_type
+    erase(basic_string<_CharT, _Traits, _Allocator>& __str, const _Up& __v) {
+  auto __old_size = __str.size();
+  __str.erase(std::remove(__str.begin(), __str.end(), __v), __str.end());
+  return __old_size - __str.size();
+}
+
+template <class _CharT, class _Traits, class _Allocator, class _Predicate>
+inline _LIBCPP_HIDE_FROM_ABI
+    typename basic_string<_CharT, _Traits, _Allocator>::size_type
+    erase_if(basic_string<_CharT, _Traits, _Allocator>& __str,
+             _Predicate __pred) {
+  auto __old_size = __str.size();
+  __str.erase(std::remove_if(__str.begin(), __str.end(), __pred),
+              __str.end());
+  return __old_size - __str.size();
+}
+#endif
+
+#if _LIBCPP_STD_VER >= 14
+// Literal suffixes for basic_string [basic.string.literals]
+inline namespace literals
+{
+  inline namespace string_literals
+  {
+    inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    basic_string<char> operator""s( const char *__str, size_t __len )
+    {
+        return basic_string<char> (__str, __len);
+    }
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+    inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    basic_string<wchar_t> operator""s( const wchar_t *__str, size_t __len )
+    {
+        return basic_string<wchar_t> (__str, __len);
+    }
+#endif
+
+#ifndef _LIBCPP_HAS_NO_CHAR8_T
+    inline _LIBCPP_HIDE_FROM_ABI constexpr
+    basic_string<char8_t> operator""s(const char8_t *__str, size_t __len)
+    {
+        return basic_string<char8_t> (__str, __len);
+    }
+#endif
+
+    inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    basic_string<char16_t> operator""s( const char16_t *__str, size_t __len )
+    {
+        return basic_string<char16_t> (__str, __len);
+    }
+
+    inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+    basic_string<char32_t> operator""s( const char32_t *__str, size_t __len )
+    {
+        return basic_string<char32_t> (__str, __len);
+    }
+  } // namespace string_literals
+} // namespace literals
+
+#if _LIBCPP_STD_VER >= 20
+template <>
+inline constexpr bool __format::__enable_insertable<std::basic_string<char>> = true;
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+template <>
+inline constexpr bool __format::__enable_insertable<std::basic_string<wchar_t>> = true;
+#endif
+#endif
+
+#endif
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#if !defined(_LIBCPP_REMOVE_TRANSITIVE_INCLUDES) && _LIBCPP_STD_VER <= 20
+#  include <algorithm>
+#  include <concepts>
+#  include <cstdlib>
+#  include <iterator>
+#  include <new>
+#  include <type_traits>
+#  include <typeinfo>
+#  include <utility>
+#endif
+
+#endif // _LIBCPP_STRING