diff --git a/libcxx/include/string b/libcxx/include/string
--- a/libcxx/include/string
+++ b/libcxx/include/string
@@ -791,120 +791,268 @@
     _LIBCPP_TEMPLATE_DATA_VIS
     static const size_type npos = -1;
 
-    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17 basic_string()
-        _NOEXCEPT_(is_nothrow_default_constructible<allocator_type>::value);
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17 basic_string()
+      _NOEXCEPT_(is_nothrow_default_constructible<allocator_type>::value)
+      : __r_(__default_init_tag(), __default_init_tag()) {
+    std::__debug_db_insert_c(this);
+    __default_init();
+  }
 
-    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17 explicit basic_string(const allocator_type& __a)
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17 explicit basic_string(const allocator_type& __a)
 #if _LIBCPP_STD_VER <= 14
-        _NOEXCEPT_(is_nothrow_copy_constructible<allocator_type>::value);
+      _NOEXCEPT_(is_nothrow_copy_constructible<allocator_type>::value)
 #else
-        _NOEXCEPT;
+      _NOEXCEPT
 #endif
+      : __r_(__default_init_tag(), __a) {
+    std::__debug_db_insert_c(this);
+    __default_init();
+  }
+
+  _LIBCPP_CONSTEXPR_AFTER_CXX17 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().__r = __str.__r_.first().__r;
+    else
+      __init_copy_ctor_external(std::__to_address(__str.__get_long_pointer()), __str.__get_long_size());
+    std::__debug_db_insert_c(this);
+  }
 
-    _LIBCPP_CONSTEXPR_AFTER_CXX17 basic_string(const basic_string& __str);
-    _LIBCPP_CONSTEXPR_AFTER_CXX17 basic_string(const basic_string& __str, const allocator_type& __a);
+  _LIBCPP_CONSTEXPR_AFTER_CXX17 basic_string(const basic_string& __str, const allocator_type& __a)
+      : __r_(__default_init_tag(), __a) {
+    if (!__str.__is_long())
+      __r_.first().__r = __str.__r_.first().__r;
+    else
+      __init_copy_ctor_external(std::__to_address(__str.__get_long_pointer()), __str.__get_long_size());
+    std::__debug_db_insert_c(this);
+  }
 
 #ifndef _LIBCPP_CXX03_LANG
-    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17
-    basic_string(basic_string&& __str)
-#if _LIBCPP_STD_VER <= 14
-        _NOEXCEPT_(is_nothrow_move_constructible<allocator_type>::value);
-#else
-        _NOEXCEPT;
-#endif
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17 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();
+    std::__debug_db_insert_c(this);
+    if (__is_long())
+      std::__debug_db_swap(this, &__str);
+  }
+
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17 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()) {
+        __zero();
+        __r_.first().__l = __str.__r_.first().__l;
+      } else {
+        __r_.first().__r = __str.__r_.first().__r;
+      }
+      __str.__default_init();
+    }
+    std::__debug_db_insert_c(this);
+    if (__is_long())
+      std::__debug_db_swap(this, &__str);
+  }
 
-    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17
-    basic_string(basic_string&& __str, const allocator_type& __a);
 #endif // _LIBCPP_CXX03_LANG
 
-    template <class = __enable_if_t<__is_allocator<_Allocator>::value, nullptr_t> >
-    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17
-    basic_string(const _CharT* __s) : __r_(__default_init_tag(), __default_init_tag()) {
-      _LIBCPP_ASSERT(__s != nullptr, "basic_string(const char*) detected nullptr");
-      __init(__s, traits_type::length(__s));
-      std::__debug_db_insert_c(this);
-    }
+  template <class = __enable_if_t<__is_allocator<_Allocator>::value, nullptr_t> >
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17 basic_string(const _CharT* __s)
+      : __r_(__default_init_tag(), __default_init_tag()) {
+    _LIBCPP_ASSERT(__s != nullptr, "basic_string(const char*) detected nullptr");
+    __init(__s, traits_type::length(__s));
+    std::__debug_db_insert_c(this);
+  }
 
-    template <class = __enable_if_t<__is_allocator<_Allocator>::value, nullptr_t> >
-        _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17
-        basic_string(const _CharT* __s, const _Allocator& __a);
+  template <class = __enable_if_t<__is_allocator<_Allocator>::value, nullptr_t> >
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17 basic_string(const _CharT* __s, const _Allocator& __a)
+      : __r_(__default_init_tag(), __a) {
+    _LIBCPP_ASSERT(__s != nullptr, "basic_string(const char*, allocator) detected nullptr");
+    __init(__s, traits_type::length(__s));
+    std::__debug_db_insert_c(this);
+  }
 
 #if _LIBCPP_STD_VER > 20
-    basic_string(nullptr_t) = delete;
+  basic_string(nullptr_t) = delete;
 #endif
 
-    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17
-    basic_string(const _CharT* __s, size_type __n);
-    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17
-    basic_string(const _CharT* __s, size_type __n, const _Allocator& __a);
-    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17
-    basic_string(size_type __n, _CharT __c);
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17 basic_string(const _CharT* __s, size_type __n)
+      : __r_(__default_init_tag(), __default_init_tag()) {
+    _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "basic_string(const char*, n) detected nullptr");
+    __init(__s, __n);
+    std::__debug_db_insert_c(this);
+  }
 
-    template <class = __enable_if_t<__is_allocator<_Allocator>::value, nullptr_t> >
-        _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17
-        basic_string(size_type __n, _CharT __c, const _Allocator& __a);
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17 basic_string(const _CharT* __s, size_type __n,
+                                                                   const _Allocator& __a)
+      : __r_(__default_init_tag(), __a) {
+    _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "basic_string(const char*, n, allocator) detected nullptr");
+    __init(__s, __n);
+    std::__debug_db_insert_c(this);
+  }
 
-    _LIBCPP_CONSTEXPR_AFTER_CXX17
-    basic_string(const basic_string& __str, size_type __pos, size_type __n,
-                 const _Allocator& __a = _Allocator());
-    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17
-    basic_string(const basic_string& __str, size_type __pos,
-                 const _Allocator& __a = _Allocator());
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17 basic_string(size_type __n, _CharT __c)
+      : __r_(__default_init_tag(), __default_init_tag()) {
+    __init(__n, __c);
+    std::__debug_db_insert_c(this);
+  }
+
+  template <class = __enable_if_t<__is_allocator<_Allocator>::value, nullptr_t> >
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17 basic_string(size_type __n, _CharT __c, const _Allocator& __a)
+      : __r_(__default_init_tag(), __a) {
+    __init(__n, __c);
+    std::__debug_db_insert_c(this);
+  }
+
+  _LIBCPP_CONSTEXPR_AFTER_CXX17
+  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));
+    std::__debug_db_insert_c(this);
+  }
+
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17 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);
+    std::__debug_db_insert_c(this);
+  }
 
-    template<class _Tp, class = __enable_if_t<__can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value && !__is_same_uncvref<_Tp, basic_string>::value> >
-        _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_AFTER_CXX17
-        basic_string(const _Tp& __t, size_type __pos, size_type __n,
-                     const allocator_type& __a = allocator_type());
+  template <class _Tp, class = __enable_if_t<__can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value &&
+                                             !__is_same_uncvref<_Tp, basic_string>::value> >
+  _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_AFTER_CXX17
+  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());
+    std::__debug_db_insert_c(this);
+  }
 
-    template<class _Tp, class = __enable_if_t<__can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value &&
-                                          !__is_same_uncvref<_Tp, basic_string>::value> >
-        _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_AFTER_CXX17
-        explicit basic_string(const _Tp& __t);
+  template <class _Tp, class = __enable_if_t<__can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value &&
+                                             !__is_same_uncvref<_Tp, basic_string>::value> >
+  _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_AFTER_CXX17 explicit basic_string(const _Tp& __t)
+      : __r_(__default_init_tag(), __default_init_tag()) {
+    __self_view __sv = __t;
+    __init(__sv.data(), __sv.size());
+    std::__debug_db_insert_c(this);
+  }
 
-    template<class _Tp, class = __enable_if_t<__can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value && !__is_same_uncvref<_Tp, basic_string>::value> >
-        _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_AFTER_CXX17
-        explicit basic_string(const _Tp& __t, const allocator_type& __a);
+  template <class _Tp, class = __enable_if_t<__can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value &&
+                                             !__is_same_uncvref<_Tp, basic_string>::value> >
+  _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
+      _LIBCPP_CONSTEXPR_AFTER_CXX17 explicit basic_string(const _Tp& __t, const allocator_type& __a)
+      : __r_(__default_init_tag(), __a) {
+    __self_view __sv = __t;
+    __init(__sv.data(), __sv.size());
+    std::__debug_db_insert_c(this);
+  }
+
+  template <class _InputIterator, class = __enable_if_t<__is_cpp17_input_iterator<_InputIterator>::value> >
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17 basic_string(_InputIterator __first, _InputIterator __last)
+      : __r_(__default_init_tag(), __default_init_tag()) {
+    __init(__first, __last);
+    std::__debug_db_insert_c(this);
+  }
+
+  template <class _InputIterator, class = __enable_if_t<__is_cpp17_input_iterator<_InputIterator>::value> >
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17 basic_string(_InputIterator __first, _InputIterator __last,
+                                                                   const allocator_type& __a)
+      : __r_(__default_init_tag(), __a) {
+    __init(__first, __last);
+    std::__debug_db_insert_c(this);
+  }
 
-    template<class _InputIterator, class = __enable_if_t<__is_cpp17_input_iterator<_InputIterator>::value> >
-        _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17
-        basic_string(_InputIterator __first, _InputIterator __last);
-    template<class _InputIterator, class = __enable_if_t<__is_cpp17_input_iterator<_InputIterator>::value> >
-        _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17
-        basic_string(_InputIterator __first, _InputIterator __last, const allocator_type& __a);
 #ifndef _LIBCPP_CXX03_LANG
-    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17
-    basic_string(initializer_list<_CharT> __il);
-    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17
-    basic_string(initializer_list<_CharT> __il, const _Allocator& __a);
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17 basic_string(initializer_list<_CharT> __il)
+      : __r_(__default_init_tag(), __default_init_tag()) {
+    __init(__il.begin(), __il.end());
+    std::__debug_db_insert_c(this);
+  }
+
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17 basic_string(initializer_list<_CharT> __il, const _Allocator& __a)
+      : __r_(__default_init_tag(), __a) {
+    __init(__il.begin(), __il.end());
+    std::__debug_db_insert_c(this);
+  }
 #endif // _LIBCPP_CXX03_LANG
 
-    inline _LIBCPP_CONSTEXPR_AFTER_CXX17 ~basic_string();
+  inline _LIBCPP_CONSTEXPR_AFTER_CXX17 ~basic_string() {
+    std::__debug_db_erase_c(this);
+    if (__is_long())
+      __alloc_traits::deallocate(__alloc(), __get_long_pointer(), __get_long_cap());
+  }
 
     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17
     operator __self_view() const _NOEXCEPT { return __self_view(data(), size()); }
 
-    _LIBCPP_CONSTEXPR_AFTER_CXX17 basic_string& operator=(const basic_string& __str);
-
-    template <class _Tp, class = __enable_if_t<__can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value &&
-                                               !__is_same_uncvref<_Tp, basic_string>::value> >
-    _LIBCPP_CONSTEXPR_AFTER_CXX17 basic_string& operator=(const _Tp& __t) {
-      __self_view __sv = __t;
-      return assign(__sv);
+  _LIBCPP_CONSTEXPR_AFTER_CXX17 basic_string& operator=(const basic_string& __str) {
+    if (this != &__str) {
+      __copy_assign_alloc(__str);
+      if (!__is_long()) {
+        if (!__str.__is_long()) {
+          __r_.first().__r = __str.__r_.first().__r;
+        } else {
+          return __assign_no_alias<true>(__str.data(), __str.size());
+        }
+      } else {
+        return __assign_no_alias<false>(__str.data(), __str.size());
+      }
     }
+    return *this;
+  }
+
+  template <
+      class _Tp,
+      class = __enable_if_t<__can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value &&
+                            !__is_same_uncvref<_Tp, basic_string>::value> >
+  _LIBCPP_CONSTEXPR_AFTER_CXX17 basic_string& operator=(const _Tp& __t) {
+    __self_view __sv = __t;
+    return assign(__sv);
+  }
 
 #ifndef _LIBCPP_CXX03_LANG
-    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17
-    basic_string& operator=(basic_string&& __str)
-        _NOEXCEPT_((__noexcept_move_assign_container<_Allocator, __alloc_traits>::value));
-     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17
-    basic_string& operator=(initializer_list<value_type> __il) {return assign(__il.begin(), __il.size());}
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17 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_AFTER_CXX17 basic_string& operator=(initializer_list<value_type> __il) {
+    return assign(__il.begin(), __il.size());
+  }
 #endif
-    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17
-    basic_string& operator=(const value_type* __s) {return assign(__s);}
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17 basic_string& operator=(const value_type* __s) {
+    return assign(__s);
+  }
 #if _LIBCPP_STD_VER > 20
-    basic_string& operator=(nullptr_t) = delete;
+  basic_string& operator=(nullptr_t) = delete;
 #endif
-    _LIBCPP_CONSTEXPR_AFTER_CXX17 basic_string& operator=(value_type __c);
+  _LIBCPP_CONSTEXPR_AFTER_CXX17 basic_string& 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());
+    __invalidate_iterators_past(1);
+    return *this;
+  }
 
     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17
     iterator begin() _NOEXCEPT
@@ -1077,54 +1225,111 @@
     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17 reference       back() _NOEXCEPT;
     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17 const_reference back() const _NOEXCEPT;
 
-    template <class _Tp>
-    _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_AFTER_CXX17
-    __enable_if_t
-        <
-            __can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value,
-            basic_string&
-        >
-                 assign(const _Tp & __t) { __self_view __sv = __t; return assign(__sv.data(), __sv.size()); }
-    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17
-    basic_string& assign(const basic_string& __str) { return *this = __str; }
+  template <class _Tp>
+  _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_AFTER_CXX17
+      __enable_if_t<__can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value, basic_string& >
+      assign(const _Tp& __t) {
+    __self_view __sv = __t;
+    return assign(__sv.data(), __sv.size());
+  }
+
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17 basic_string& assign(const basic_string& __str) {
+    return *this = __str;
+  }
+
 #ifndef _LIBCPP_CXX03_LANG
-    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17
-    basic_string& assign(basic_string&& __str)
-        _NOEXCEPT_((__noexcept_move_assign_container<_Allocator, __alloc_traits>::value))
-        {*this = std::move(__str); return *this;}
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17 basic_string&
+  assign(basic_string&& __str) _NOEXCEPT_((__noexcept_move_assign_container<_Allocator, __alloc_traits>::value)) {
+    *this = std::move(__str);
+    return *this;
+  }
 #endif
-    _LIBCPP_CONSTEXPR_AFTER_CXX17 basic_string& assign(const basic_string& __str, size_type __pos, size_type __n=npos);
-    template <class _Tp>
-    _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_AFTER_CXX17
-    __enable_if_t
-        <
-            __can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value
-            && !__is_same_uncvref<_Tp, basic_string>::value,
-            basic_string&
-        >
-                  assign(const _Tp & __t, size_type __pos, size_type __n=npos);
-    _LIBCPP_CONSTEXPR_AFTER_CXX17 basic_string& assign(const value_type* __s, size_type __n);
-    _LIBCPP_CONSTEXPR_AFTER_CXX17 basic_string& assign(const value_type* __s);
-    _LIBCPP_CONSTEXPR_AFTER_CXX17 basic_string& assign(size_type __n, value_type __c);
-    template<class _InputIterator>
-    _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_AFTER_CXX17
-    __enable_if_t
-        <
-            __is_exactly_cpp17_input_iterator<_InputIterator>::value,
-            basic_string&
-        >
-        assign(_InputIterator __first, _InputIterator __last);
-    template<class _ForwardIterator>
-    _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_AFTER_CXX17
-    __enable_if_t
-        <
-            __is_cpp17_forward_iterator<_ForwardIterator>::value,
-            basic_string&
-        >
-        assign(_ForwardIterator __first, _ForwardIterator __last);
+
+  _LIBCPP_CONSTEXPR_AFTER_CXX17 basic_string& assign(const basic_string& __str, size_type __pos, size_type __n = npos) {
+    size_type __sz = __str.size();
+    if (__pos > __sz)
+      __throw_out_of_range();
+    return assign(__str.data() + __pos, std::min(__n, __sz - __pos));
+  }
+
+  template <class _Tp>
+  _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_AFTER_CXX17 __enable_if_t<
+      __can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value && !__is_same_uncvref<_Tp, basic_string>::value,
+      basic_string&>
+  assign(const _Tp& __t, size_type __pos, size_type __n = npos) {
+    __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));
+  }
+
+  _LIBCPP_CONSTEXPR_AFTER_CXX17 basic_string& assign(const value_type* __s, size_type __n) {
+    _LIBCPP_ASSERT(__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);
+  }
+
+  _LIBCPP_CONSTEXPR_AFTER_CXX17 basic_string& assign(const value_type* __s) {
+    _LIBCPP_ASSERT(__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);
+  }
+
+  _LIBCPP_CONSTEXPR_AFTER_CXX17 basic_string& assign(size_type __n, value_type __c) {
+    size_type __cap = capacity();
+    if (__cap < __n) {
+      size_type __sz = size();
+      __grow_by(__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 _InputIterator>
+  _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_AFTER_CXX17
+      __enable_if_t<__is_exactly_cpp17_input_iterator<_InputIterator>::value, basic_string&>
+      assign(_InputIterator __first, _InputIterator __last) {
+    const basic_string __temp(__first, __last, __alloc());
+    assign(__temp.data(), __temp.size());
+    return *this;
+  }
+
+  template <class _ForwardIterator>
+  _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_AFTER_CXX17
+      __enable_if_t<__is_cpp17_forward_iterator<_ForwardIterator>::value, basic_string&>
+      assign(_ForwardIterator __first, _ForwardIterator __last) {
+    size_type __cap = capacity();
+    size_type __n =
+        __string_is_trivial_iterator<_ForwardIterator>::value
+            ? static_cast<size_type>(std::distance(__first, __last))
+            : 0;
+
+    if (__string_is_trivial_iterator<_ForwardIterator>::value && (__cap >= __n || !__addr_in_range(*__first))) {
+      if (__cap < __n) {
+        size_type __sz = size();
+        __grow_by(__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);
+      __invalidate_iterators_past(__n);
+    } else {
+      const basic_string __temp(__first, __last, __alloc());
+      assign(__temp.data(), __temp.size());
+    }
+    return *this;
+  }
+
 #ifndef _LIBCPP_CXX03_LANG
-    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17
-    basic_string& assign(initializer_list<value_type> __il) {return assign(__il.begin(), __il.size());}
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17 basic_string& assign(initializer_list<value_type> __il) {
+    return assign(__il.begin(), __il.size());
+  }
 #endif // _LIBCPP_CXX03_LANG
 
     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17
@@ -1873,30 +2078,6 @@
 #endif // _LIBCPP_ENABLE_DEBUG_MODE
 }
 
-template <class _CharT, class _Traits, class _Allocator>
-inline _LIBCPP_CONSTEXPR_AFTER_CXX17
-basic_string<_CharT, _Traits, _Allocator>::basic_string()
-    _NOEXCEPT_(is_nothrow_default_constructible<allocator_type>::value)
-     : __r_(__default_init_tag(), __default_init_tag())
-{
-    std::__debug_db_insert_c(this);
-    __default_init();
-}
-
-template <class _CharT, class _Traits, class _Allocator>
-inline _LIBCPP_CONSTEXPR_AFTER_CXX17
-basic_string<_CharT, _Traits, _Allocator>::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)
-{
-    std::__debug_db_insert_c(this);
-    __default_init();
-}
-
 template <class _CharT, class _Traits, class _Allocator>
 _LIBCPP_CONSTEXPR_AFTER_CXX17
 void basic_string<_CharT, _Traits, _Allocator>::__init(const value_type* __s,
@@ -1954,64 +2135,6 @@
     traits_type::assign(__p[__sz], value_type());
 }
 
-template <class _CharT, class _Traits, class _Allocator>
-template <class>
-_LIBCPP_CONSTEXPR_AFTER_CXX17
-basic_string<_CharT, _Traits, _Allocator>::basic_string(const _CharT* __s, const _Allocator& __a)
-    : __r_(__default_init_tag(), __a)
-{
-    _LIBCPP_ASSERT(__s != nullptr, "basic_string(const char*, allocator) detected nullptr");
-    __init(__s, traits_type::length(__s));
-    std::__debug_db_insert_c(this);
-}
-
-template <class _CharT, class _Traits, class _Allocator>
-inline _LIBCPP_CONSTEXPR_AFTER_CXX17
-basic_string<_CharT, _Traits, _Allocator>::basic_string(const _CharT* __s, size_type __n)
-     : __r_(__default_init_tag(), __default_init_tag())
-{
-    _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "basic_string(const char*, n) detected nullptr");
-    __init(__s, __n);
-    std::__debug_db_insert_c(this);
-}
-
-template <class _CharT, class _Traits, class _Allocator>
-inline _LIBCPP_CONSTEXPR_AFTER_CXX17
-basic_string<_CharT, _Traits, _Allocator>::basic_string(const _CharT* __s, size_type __n, const _Allocator& __a)
-    : __r_(__default_init_tag(), __a)
-{
-    _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "basic_string(const char*, n, allocator) detected nullptr");
-    __init(__s, __n);
-    std::__debug_db_insert_c(this);
-}
-
-template <class _CharT, class _Traits, class _Allocator>
-_LIBCPP_CONSTEXPR_AFTER_CXX17
-basic_string<_CharT, _Traits, _Allocator>::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().__r = __str.__r_.first().__r;
-    else
-        __init_copy_ctor_external(std::__to_address(__str.__get_long_pointer()),
-                                  __str.__get_long_size());
-    std::__debug_db_insert_c(this);
-}
-
-template <class _CharT, class _Traits, class _Allocator>
-_LIBCPP_CONSTEXPR_AFTER_CXX17
-basic_string<_CharT, _Traits, _Allocator>::basic_string(
-    const basic_string& __str, const allocator_type& __a)
-    : __r_(__default_init_tag(), __a)
-{
-    if (!__str.__is_long())
-        __r_.first().__r = __str.__r_.first().__r;
-    else
-        __init_copy_ctor_external(std::__to_address(__str.__get_long_pointer()),
-                                  __str.__get_long_size());
-    std::__debug_db_insert_c(this);
-}
-
 template <class _CharT, class _Traits, class _Allocator>
 _LIBCPP_CONSTEXPR_AFTER_CXX17
 void basic_string<_CharT, _Traits, _Allocator>::__init_copy_ctor_external(
@@ -2035,48 +2158,6 @@
   traits_type::copy(std::__to_address(__p), __s, __sz + 1);
 }
 
-#ifndef _LIBCPP_CXX03_LANG
-
-template <class _CharT, class _Traits, class _Allocator>
-inline _LIBCPP_CONSTEXPR_AFTER_CXX17
-basic_string<_CharT, _Traits, _Allocator>::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();
-    std::__debug_db_insert_c(this);
-    if (__is_long())
-        std::__debug_db_swap(this, &__str);
-}
-
-template <class _CharT, class _Traits, class _Allocator>
-inline _LIBCPP_CONSTEXPR_AFTER_CXX17
-basic_string<_CharT, _Traits, _Allocator>::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()) {
-            __zero();
-            __r_.first().__l = __str.__r_.first().__l;
-        } else {
-            __r_.first().__r = __str.__r_.first().__r;
-        }
-        __str.__default_init();
-    }
-    std::__debug_db_insert_c(this);
-    if (__is_long())
-        std::__debug_db_swap(this, &__str);
-}
-
-#endif // _LIBCPP_CXX03_LANG
-
 template <class _CharT, class _Traits, class _Allocator>
 _LIBCPP_CONSTEXPR_AFTER_CXX17
 void
@@ -2105,87 +2186,6 @@
     traits_type::assign(__p[__n], value_type());
 }
 
-template <class _CharT, class _Traits, class _Allocator>
-inline _LIBCPP_CONSTEXPR_AFTER_CXX17
-basic_string<_CharT, _Traits, _Allocator>::basic_string(size_type __n, _CharT __c)
-     : __r_(__default_init_tag(), __default_init_tag())
-{
-    __init(__n, __c);
-    std::__debug_db_insert_c(this);
-}
-
-template <class _CharT, class _Traits, class _Allocator>
-template <class>
-_LIBCPP_CONSTEXPR_AFTER_CXX17
-basic_string<_CharT, _Traits, _Allocator>::basic_string(size_type __n, _CharT __c, const _Allocator& __a)
-    : __r_(__default_init_tag(), __a)
-{
-    __init(__n, __c);
-    std::__debug_db_insert_c(this);
-}
-
-template <class _CharT, class _Traits, class _Allocator>
-_LIBCPP_CONSTEXPR_AFTER_CXX17
-basic_string<_CharT, _Traits, _Allocator>::basic_string(const basic_string& __str,
-                                                        size_type __pos, size_type __n,
-                                                        const _Allocator& __a)
-    : __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));
-    std::__debug_db_insert_c(this);
-}
-
-template <class _CharT, class _Traits, class _Allocator>
-inline _LIBCPP_CONSTEXPR_AFTER_CXX17
-basic_string<_CharT, _Traits, _Allocator>::basic_string(const basic_string& __str, size_type __pos,
-                                                        const _Allocator& __a)
-    : __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);
-    std::__debug_db_insert_c(this);
-}
-
-template <class _CharT, class _Traits, class _Allocator>
-template <class _Tp, class>
-_LIBCPP_CONSTEXPR_AFTER_CXX17
-basic_string<_CharT, _Traits, _Allocator>::basic_string(
-             const _Tp& __t, size_type __pos, size_type __n, const allocator_type& __a)
-    : __r_(__default_init_tag(), __a)
-{
-    __self_view __sv0 = __t;
-    __self_view __sv = __sv0.substr(__pos, __n);
-    __init(__sv.data(), __sv.size());
-    std::__debug_db_insert_c(this);
-}
-
-template <class _CharT, class _Traits, class _Allocator>
-template <class _Tp, class>
-_LIBCPP_CONSTEXPR_AFTER_CXX17
-basic_string<_CharT, _Traits, _Allocator>::basic_string(const _Tp & __t)
-     : __r_(__default_init_tag(), __default_init_tag())
-{
-    __self_view __sv = __t;
-    __init(__sv.data(), __sv.size());
-    std::__debug_db_insert_c(this);
-}
-
-template <class _CharT, class _Traits, class _Allocator>
-template <class _Tp, class>
-_LIBCPP_CONSTEXPR_AFTER_CXX17
-basic_string<_CharT, _Traits, _Allocator>::basic_string(const _Tp & __t, const _Allocator& __a)
-    : __r_(__default_init_tag(), __a)
-{
-    __self_view __sv = __t;
-    __init(__sv.data(), __sv.size());
-    std::__debug_db_insert_c(this);
-}
-
 template <class _CharT, class _Traits, class _Allocator>
 template <class _InputIterator>
 _LIBCPP_CONSTEXPR_AFTER_CXX17
@@ -2261,60 +2261,6 @@
 #endif  // _LIBCPP_NO_EXCEPTIONS
 }
 
-template <class _CharT, class _Traits, class _Allocator>
-template<class _InputIterator, class>
-inline _LIBCPP_CONSTEXPR_AFTER_CXX17
-basic_string<_CharT, _Traits, _Allocator>::basic_string(_InputIterator __first, _InputIterator __last)
-     : __r_(__default_init_tag(), __default_init_tag())
-{
-    __init(__first, __last);
-    std::__debug_db_insert_c(this);
-}
-
-template <class _CharT, class _Traits, class _Allocator>
-template<class _InputIterator, class>
-inline _LIBCPP_CONSTEXPR_AFTER_CXX17
-basic_string<_CharT, _Traits, _Allocator>::basic_string(_InputIterator __first, _InputIterator __last,
-                                                        const allocator_type& __a)
-    : __r_(__default_init_tag(), __a)
-{
-    __init(__first, __last);
-    std::__debug_db_insert_c(this);
-}
-
-#ifndef _LIBCPP_CXX03_LANG
-
-template <class _CharT, class _Traits, class _Allocator>
-inline _LIBCPP_CONSTEXPR_AFTER_CXX17
-basic_string<_CharT, _Traits, _Allocator>::basic_string(
-    initializer_list<_CharT> __il)
-     : __r_(__default_init_tag(), __default_init_tag())
-{
-    __init(__il.begin(), __il.end());
-    std::__debug_db_insert_c(this);
-}
-
-template <class _CharT, class _Traits, class _Allocator>
-inline _LIBCPP_CONSTEXPR_AFTER_CXX17
-basic_string<_CharT, _Traits, _Allocator>::basic_string(
-    initializer_list<_CharT> __il, const _Allocator& __a)
-    : __r_(__default_init_tag(), __a)
-{
-    __init(__il.begin(), __il.end());
-    std::__debug_db_insert_c(this);
-}
-
-#endif // _LIBCPP_CXX03_LANG
-
-template <class _CharT, class _Traits, class _Allocator>
-_LIBCPP_CONSTEXPR_AFTER_CXX17
-basic_string<_CharT, _Traits, _Allocator>::~basic_string()
-{
-    std::__debug_db_erase_c(this);
-    if (__is_long())
-        __alloc_traits::deallocate(__alloc(), __get_long_pointer(), __get_long_cap());
-}
-
 template <class _CharT, class _Traits, class _Allocator>
 _LIBCPP_CONSTEXPR_AFTER_CXX17
 void
@@ -2421,75 +2367,6 @@
   }
 }
 
-template <class _CharT, class _Traits, class _Allocator>
-_LIBCPP_CONSTEXPR_AFTER_CXX17
-basic_string<_CharT, _Traits, _Allocator>&
-basic_string<_CharT, _Traits, _Allocator>::assign(const value_type* __s, size_type __n)
-{
-    _LIBCPP_ASSERT(__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_AFTER_CXX17
-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(__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_AFTER_CXX17
-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());
-    __invalidate_iterators_past(1);
-    return *this;
-}
-
-template <class _CharT, class _Traits, class _Allocator>
-_LIBCPP_CONSTEXPR_AFTER_CXX17
-basic_string<_CharT, _Traits, _Allocator>&
-basic_string<_CharT, _Traits, _Allocator>::operator=(const basic_string& __str)
-{
-  if (this != &__str) {
-    __copy_assign_alloc(__str);
-    if (!__is_long()) {
-      if (!__str.__is_long()) {
-        __r_.first().__r = __str.__r_.first().__r;
-      } 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>
@@ -2534,101 +2411,8 @@
   }
 }
 
-template <class _CharT, class _Traits, class _Allocator>
-inline _LIBCPP_CONSTEXPR_AFTER_CXX17
-basic_string<_CharT, _Traits, _Allocator>&
-basic_string<_CharT, _Traits, _Allocator>::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;
-}
-
 #endif
 
-template <class _CharT, class _Traits, class _Allocator>
-template<class _InputIterator>
-_LIBCPP_CONSTEXPR_AFTER_CXX17
-__enable_if_t
-<
-     __is_exactly_cpp17_input_iterator<_InputIterator>::value,
-    basic_string<_CharT, _Traits, _Allocator>&
->
-basic_string<_CharT, _Traits, _Allocator>::assign(_InputIterator __first, _InputIterator __last)
-{
-    const basic_string __temp(__first, __last, __alloc());
-    assign(__temp.data(), __temp.size());
-    return *this;
-}
-
-template <class _CharT, class _Traits, class _Allocator>
-template<class _ForwardIterator>
-_LIBCPP_CONSTEXPR_AFTER_CXX17
-__enable_if_t
-<
-    __is_cpp17_forward_iterator<_ForwardIterator>::value,
-    basic_string<_CharT, _Traits, _Allocator>&
->
-basic_string<_CharT, _Traits, _Allocator>::assign(_ForwardIterator __first, _ForwardIterator __last)
-{
-    size_type __cap = capacity();
-    size_type __n = __string_is_trivial_iterator<_ForwardIterator>::value ?
-        static_cast<size_type>(std::distance(__first, __last)) : 0;
-
-    if (__string_is_trivial_iterator<_ForwardIterator>::value &&
-        (__cap >= __n || !__addr_in_range(*__first)))
-    {
-        if (__cap < __n)
-        {
-            size_type __sz = size();
-            __grow_by(__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);
-        __invalidate_iterators_past(__n);
-    }
-    else
-    {
-        const basic_string __temp(__first, __last, __alloc());
-        assign(__temp.data(), __temp.size());
-    }
-    return *this;
-}
-
-template <class _CharT, class _Traits, class _Allocator>
-_LIBCPP_CONSTEXPR_AFTER_CXX17
-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>
-_LIBCPP_CONSTEXPR_AFTER_CXX17
-__enable_if_t
-<
-    __can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value
-    && !__is_same_uncvref<_Tp, basic_string<_CharT, _Traits, _Allocator> >::value,
-    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_AFTER_CXX17
 basic_string<_CharT, _Traits, _Allocator>&
@@ -2636,18 +2420,6 @@
   return __assign_external(__s, traits_type::length(__s));
 }
 
-template <class _CharT, class _Traits, class _Allocator>
-_LIBCPP_CONSTEXPR_AFTER_CXX17
-basic_string<_CharT, _Traits, _Allocator>&
-basic_string<_CharT, _Traits, _Allocator>::assign(const value_type* __s)
-{
-    _LIBCPP_ASSERT(__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>