diff --git a/libcxx/include/string b/libcxx/include/string
--- a/libcxx/include/string
+++ b/libcxx/include/string
@@ -1010,9 +1010,12 @@
     }
 
 #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));
+  _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
@@ -1065,7 +1068,17 @@
     _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;
+
+  _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;
     }
@@ -1093,9 +1106,15 @@
     _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_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 reference operator[](size_type __pos) _NOEXCEPT;
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 const_reference operator[](size_type __pos) const _NOEXCEPT {
+    _LIBCPP_ASSERT(__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(__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);
@@ -1130,8 +1149,9 @@
     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);
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string& append(const basic_string& __str) {
+        return append(__str.data(), __str.size());
+  }
 
     template <class _Tp>
     _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_SINCE_CXX20
@@ -1189,10 +1209,26 @@
 
     _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_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 const_reference front() const _NOEXCEPT;
-    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 reference       back() _NOEXCEPT;
-    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 const_reference back() const _NOEXCEPT;
+
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 reference front() _NOEXCEPT {
+    _LIBCPP_ASSERT(!empty(), "string::front(): string is empty");
+    return *__get_pointer();
+  }
+
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 const_reference front() const _NOEXCEPT {
+    _LIBCPP_ASSERT(!empty(), "string::front(): string is empty");
+    return *data();
+  }
+
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 reference back() _NOEXCEPT {
+    _LIBCPP_ASSERT(!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(!empty(), "string::back(): string is empty");
+    return *(data() + size() - 1);
+  }
 
     template <class _Tp>
     _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_SINCE_CXX20
@@ -1244,8 +1280,10 @@
     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);
+  _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>
     _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_SINCE_CXX20
@@ -1271,8 +1309,16 @@
     _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);
-    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
-    iterator      insert(const_iterator __pos, size_type __n, value_type __c);
+
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 iterator
+  insert(const_iterator __pos, size_type __n, value_type __c) {
+    _LIBCPP_DEBUG_ASSERT(__get_const_db()->__find_c_from_i(&__pos) == this,
+                         "string::insert(iterator, n, value) called with an iterator not referring to this string");
+    difference_type __p = __pos - begin();
+    insert(static_cast<size_type>(__p), __n, __c);
+    return begin() + __p;
+  }
+
     template<class _InputIterator>
     _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_SINCE_CXX20
     __enable_if_t
@@ -1301,8 +1347,10 @@
     _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);
+  _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>
     _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_SINCE_CXX20
@@ -1326,8 +1374,12 @@
     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);
+
+  _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>
     _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_SINCE_CXX20
@@ -1338,12 +1390,21 @@
         >
                   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);
-    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
-    basic_string& replace(const_iterator __i1, const_iterator __i2, const value_type* __s);
-    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
-    basic_string& replace(const_iterator __i1, const_iterator __i2, size_type __n, value_type __c);
+  _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>
     _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS _LIBCPP_CONSTEXPR_SINCE_CXX20
     __enable_if_t
@@ -1800,8 +1861,9 @@
     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);
+  _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.
@@ -2511,17 +2573,6 @@
   }
 }
 
-template <class _CharT, class _Traits, class _Allocator>
-inline _LIBCPP_CONSTEXPR_SINCE_CXX20
-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>
@@ -2762,14 +2813,6 @@
     return *this;
 }
 
-template <class _CharT, class _Traits, class _Allocator>
-inline _LIBCPP_CONSTEXPR_SINCE_CXX20
-basic_string<_CharT, _Traits, _Allocator>&
-basic_string<_CharT, _Traits, _Allocator>::append(const basic_string& __str)
-{
-    return append(__str.data(), __str.size());
-}
-
 template <class _CharT, class _Traits, class _Allocator>
 _LIBCPP_CONSTEXPR_SINCE_CXX20
 basic_string<_CharT, _Traits, _Allocator>&
@@ -2927,14 +2970,6 @@
     }
 }
 
-template <class _CharT, class _Traits, class _Allocator>
-inline _LIBCPP_CONSTEXPR_SINCE_CXX20
-basic_string<_CharT, _Traits, _Allocator>&
-basic_string<_CharT, _Traits, _Allocator>::insert(size_type __pos1, const basic_string& __str)
-{
-    return insert(__pos1, __str.data(), __str.size());
-}
-
 template <class _CharT, class _Traits, class _Allocator>
 _LIBCPP_CONSTEXPR_SINCE_CXX20
 basic_string<_CharT, _Traits, _Allocator>&
@@ -3005,19 +3040,6 @@
     return begin() + static_cast<difference_type>(__ip);
 }
 
-template <class _CharT, class _Traits, class _Allocator>
-inline _LIBCPP_CONSTEXPR_SINCE_CXX20
-typename basic_string<_CharT, _Traits, _Allocator>::iterator
-basic_string<_CharT, _Traits, _Allocator>::insert(const_iterator __pos, size_type __n, value_type __c)
-{
-  _LIBCPP_DEBUG_ASSERT(__get_const_db()->__find_c_from_i(&__pos) == this,
-                       "string::insert(iterator, n, value) called with an iterator not"
-                       " referring to this string");
-  difference_type __p = __pos - begin();
-  insert(static_cast<size_type>(__p), __n, __c);
-  return begin() + __p;
-}
-
 // replace
 
 template <class _CharT, class _Traits, class _Allocator>
@@ -3119,14 +3141,6 @@
     return replace(__i1, __i2, __temp);
 }
 
-template <class _CharT, class _Traits, class _Allocator>
-inline _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)
-{
-    return replace(__pos1, __n1, __str.data(), __str.size());
-}
-
 template <class _CharT, class _Traits, class _Allocator>
 _LIBCPP_CONSTEXPR_SINCE_CXX20
 basic_string<_CharT, _Traits, _Allocator>&
@@ -3166,39 +3180,6 @@
     return replace(__pos, __n1, __s, traits_type::length(__s));
 }
 
-template <class _CharT, class _Traits, class _Allocator>
-inline _LIBCPP_CONSTEXPR_SINCE_CXX20
-basic_string<_CharT, _Traits, _Allocator>&
-basic_string<_CharT, _Traits, _Allocator>::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 _CharT, class _Traits, class _Allocator>
-inline _LIBCPP_CONSTEXPR_SINCE_CXX20
-basic_string<_CharT, _Traits, _Allocator>&
-basic_string<_CharT, _Traits, _Allocator>::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);
-}
-
-template <class _CharT, class _Traits, class _Allocator>
-inline _LIBCPP_CONSTEXPR_SINCE_CXX20
-basic_string<_CharT, _Traits, _Allocator>&
-basic_string<_CharT, _Traits, _Allocator>::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);
-}
-
-template <class _CharT, class _Traits, class _Allocator>
-inline _LIBCPP_CONSTEXPR_SINCE_CXX20
-basic_string<_CharT, _Traits, _Allocator>&
-basic_string<_CharT, _Traits, _Allocator>::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);
-}
-
 // erase
 
 // 'externally instantiated' erase() implementation, called when __n != npos.
@@ -3295,14 +3276,6 @@
     }
 }
 
-template <class _CharT, class _Traits, class _Allocator>
-inline _LIBCPP_CONSTEXPR_SINCE_CXX20
-void
-basic_string<_CharT, _Traits, _Allocator>::__erase_to_end(size_type __pos)
-{
-  __null_terminate_at(std::__to_address(__get_pointer()), __pos);
-}
-
 template <class _CharT, class _Traits, class _Allocator>
 _LIBCPP_CONSTEXPR_SINCE_CXX20
 void
@@ -3326,20 +3299,6 @@
         __erase_to_end(__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>::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;
-    }
-}
-
 template <class _CharT, class _Traits, class _Allocator>
 _LIBCPP_CONSTEXPR_SINCE_CXX20
 void
@@ -3436,24 +3395,6 @@
     std::__debug_db_invalidate_all(this);
 }
 
-template <class _CharT, class _Traits, class _Allocator>
-inline _LIBCPP_CONSTEXPR_SINCE_CXX20
-typename basic_string<_CharT, _Traits, _Allocator>::const_reference
-basic_string<_CharT, _Traits, _Allocator>::operator[](size_type __pos) const _NOEXCEPT
-{
-    _LIBCPP_ASSERT(__pos <= size(), "string index out of bounds");
-    return *(data() + __pos);
-}
-
-template <class _CharT, class _Traits, class _Allocator>
-inline _LIBCPP_CONSTEXPR_SINCE_CXX20
-typename basic_string<_CharT, _Traits, _Allocator>::reference
-basic_string<_CharT, _Traits, _Allocator>::operator[](size_type __pos) _NOEXCEPT
-{
-    _LIBCPP_ASSERT(__pos <= size(), "string index out of bounds");
-    return *(__get_pointer() + __pos);
-}
-
 template <class _CharT, class _Traits, class _Allocator>
 _LIBCPP_CONSTEXPR_SINCE_CXX20
 typename basic_string<_CharT, _Traits, _Allocator>::const_reference
@@ -3474,42 +3415,6 @@
     return (*this)[__n];
 }
 
-template <class _CharT, class _Traits, class _Allocator>
-inline _LIBCPP_CONSTEXPR_SINCE_CXX20
-typename basic_string<_CharT, _Traits, _Allocator>::reference
-basic_string<_CharT, _Traits, _Allocator>::front() _NOEXCEPT
-{
-    _LIBCPP_ASSERT(!empty(), "string::front(): string is empty");
-    return *__get_pointer();
-}
-
-template <class _CharT, class _Traits, class _Allocator>
-inline _LIBCPP_CONSTEXPR_SINCE_CXX20
-typename basic_string<_CharT, _Traits, _Allocator>::const_reference
-basic_string<_CharT, _Traits, _Allocator>::front() const _NOEXCEPT
-{
-    _LIBCPP_ASSERT(!empty(), "string::front(): string is empty");
-    return *data();
-}
-
-template <class _CharT, class _Traits, class _Allocator>
-inline _LIBCPP_CONSTEXPR_SINCE_CXX20
-typename basic_string<_CharT, _Traits, _Allocator>::reference
-basic_string<_CharT, _Traits, _Allocator>::back() _NOEXCEPT
-{
-    _LIBCPP_ASSERT(!empty(), "string::back(): string is empty");
-    return *(__get_pointer() + size() - 1);
-}
-
-template <class _CharT, class _Traits, class _Allocator>
-inline _LIBCPP_CONSTEXPR_SINCE_CXX20
-typename basic_string<_CharT, _Traits, _Allocator>::const_reference
-basic_string<_CharT, _Traits, _Allocator>::back() const _NOEXCEPT
-{
-    _LIBCPP_ASSERT(!empty(), "string::back(): string is empty");
-    return *(data() + size() - 1);
-}
-
 template <class _CharT, class _Traits, class _Allocator>
 _LIBCPP_CONSTEXPR_SINCE_CXX20
 typename basic_string<_CharT, _Traits, _Allocator>::size_type