Get simple prototype of insert_tests working for unordered_node_map

include/boost/unordered/detail/foa.hpp

@@ -1375,13 +1375,14 @@ public:
   template<typename... Args>
   BOOST_FORCEINLINE std::pair<iterator,bool> emplace(Args&&... args)
   {
-    using emplace_type = typename std::conditional<
-      std::is_constructible<
-        init_type, Args...
-      >::value,
-      init_type,
-      value_type
-    >::type;
+    using emplace_type = typename type_policy::emplace_type;
+    // using emplace_type = typename std::conditional<
+    //   std::is_constructible<
+    //     init_type, Args...
+    //   >::value,
+    //   init_type,
+    //   value_type
+    // >::type;
     return emplace_impl(emplace_type(std::forward<Args>(args)...));
   }
 

include/boost/unordered/unordered_flat_map.hpp

@@ -45,6 +45,8 @@ namespace boost {
         using moved_type = std::pair<raw_key_type&&, raw_mapped_type&&>;
         using value_type = std::pair<Key const, T>;
 
+        using emplace_type = value_type;
+
         template <class K, class V>
         static raw_key_type const& extract(std::pair<K, V> const& kv)
         {

include/boost/unordered/unordered_flat_set.hpp

@@ -38,6 +38,9 @@ namespace boost {
         using key_type = Key;
         using init_type = Key;
         using value_type = Key;
+
+        using emplace_type = value_type;
+
         static Key const& extract(value_type const& key) { return key; }
         static Key&& move(value_type& x) { return std::move(x); }
       };

include/boost/unordered/unordered_node_map.hpp

@@ -0,0 +1,849 @@
+// Copyright (C) 2022 Christian Mazakas
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+#ifndef BOOST_UNORDERED_UNORDERED_NODE_MAP_HPP_INCLUDED
+#define BOOST_UNORDERED_UNORDERED_NODE_MAP_HPP_INCLUDED
+
+#include <boost/config.hpp>
+#if defined(BOOST_HAS_PRAGMA_ONCE)
+#pragma once
+#endif
+
+#include <boost/unordered/detail/foa.hpp>
+#include <boost/unordered/detail/type_traits.hpp>
+#include <boost/unordered/unordered_node_map_fwd.hpp>
+
+#include <boost/core/allocator_access.hpp>
+#include <boost/functional/hash.hpp>
+#include <boost/iterator/indirect_iterator.hpp>
+#include <boost/throw_exception.hpp>
+
+#include <initializer_list>
+#include <iterator>
+#include <stdexcept>
+#include <type_traits>
+#include <utility>
+
+namespace boost {
+  namespace unordered {
+
+#if defined(BOOST_MSVC)
+#pragma warning(push)
+#pragma warning(disable : 4714) /* marked as __forceinline not inlined */
+#endif
+
+    namespace detail {
+      template <typename Allocator> class ptr_allocator_adaptor
+      {
+        using alloc_traits = std::allocator_traits<Allocator>;
+        using ptr_allocator = typename alloc_traits::template rebind_alloc<
+          typename Allocator::value_type*>;
+        using ptr_alloc_traits = std::allocator_traits<ptr_allocator>;
+
+        template <class U> friend class ptr_allocator_adaptor;
+
+        Allocator al;
+
+      public:
+        using pointer = typename boost::allocator_pointer<ptr_allocator>::type;
+        using const_pointer =
+          typename boost::allocator_const_pointer<ptr_allocator>::type;
+
+        using void_pointer =
+          typename boost::allocator_void_pointer<ptr_allocator>::type;
+
+        using const_void_pointer =
+          typename boost::allocator_const_void_pointer<ptr_allocator>::type;
+
+        using value_type = typename Allocator::value_type*;
+        using size_type =
+          typename boost::allocator_size_type<ptr_allocator>::type;
+
+        using difference_type =
+          typename boost::allocator_difference_type<ptr_allocator>::type;
+
+        template <typename U> struct rebind
+        {
+          using other = ptr_allocator_adaptor<
+            typename alloc_traits::template rebind_alloc<U> >;
+        };
+
+        ptr_allocator_adaptor() = default;
+        ptr_allocator_adaptor(const Allocator& al_) : al{al_} {}
+
+        template <typename Allocator2>
+        ptr_allocator_adaptor(
+          const ptr_allocator_adaptor<Allocator2>& x) noexcept : al{x.al}
+        {
+        }
+
+        template <typename Allocator2>
+        bool operator==(
+          const ptr_allocator_adaptor<Allocator2>& x) const noexcept
+        {
+          return al == x.al;
+        }
+
+        template <typename Allocator2>
+        bool operator!=(
+          const ptr_allocator_adaptor<Allocator2>& x) const noexcept
+        {
+          return al != x.al;
+        }
+
+        pointer allocate(std::size_t n)
+        {
+          ptr_allocator pal = al;
+          return ptr_alloc_traits::allocate(pal, n);
+        }
+
+        void deallocate(pointer p, std::size_t n) noexcept
+        {
+          ptr_allocator pal = al;
+          ptr_alloc_traits::deallocate(pal, p, n);
+        }
+
+        void construct(value_type* p, const value_type& x)
+        {
+          this->construct(p, *x);
+        }
+
+        void construct(value_type* p, value_type&& x)
+        {
+          *p = x;
+          x = nullptr;
+        }
+
+        template <typename... Args>
+        void construct(value_type* p, Args&&... args)
+        {
+          *p = boost::to_address(alloc_traits::allocate(al, 1));
+          try {
+            alloc_traits::construct(al, *p, std::forward<Args>(args)...);
+          } catch (...) {
+            alloc_traits::deallocate(al,
+              boost::pointer_traits<typename alloc_traits::pointer>::pointer_to(
+                **p),
+              1);
+            throw;
+          }
+        }
+
+        void destroy(value_type* p) noexcept
+        {
+          if (*p) {
+            alloc_traits::destroy(al, *p);
+            alloc_traits::deallocate(al, *p, 1);
+          }
+        }
+      };
+    } // namespace detail
+
+    template <class Key, class T, class Hash, class KeyEqual, class Allocator>
+    class unordered_node_map
+    {
+      struct map_types
+      {
+        using key_type = Key;
+        using raw_key_type = typename std::remove_const<Key>::type;
+        using raw_mapped_type = typename std::remove_const<T>::type;
+
+        using init_type = std::pair<Key const, T>*;
+        using moved_type = init_type;
+        using value_type = init_type;
+
+        using emplace_type = std::pair<Key const, T>;
+
+        template <class K, class V>
+        static raw_key_type const& extract(std::pair<K, V> const& kv)
+        {
+          return kv.first;
+        }
+
+        template <class K, class V>
+        static raw_key_type const& extract(std::pair<K, V> const* kv)
+        {
+          return kv->first;
+        }
+
+        static value_type&& move(value_type& x) { return std::move(x); }
+      };
+
+      using table_type = detail::foa::table<map_types, Hash, KeyEqual,
+        detail::ptr_allocator_adaptor<typename boost::allocator_rebind<
+          Allocator, std::pair<Key const, T> >::type> >;
+
+      table_type table_;
+
+      template <class K, class V, class H, class KE, class A, class Pred>
+      typename unordered_node_map<K, V, H, KE, A>::size_type friend erase_if(
+        unordered_node_map<K, V, H, KE, A>& set, Pred pred);
+
+    public:
+      using key_type = Key;
+      using mapped_type = T;
+      using value_type = std::pair<Key const, T>;
+      using init_type = std::pair<typename map_types::raw_key_type,
+        typename map_types::raw_mapped_type>;
+      using size_type = std::size_t;
+      using difference_type = std::ptrdiff_t;
+      using hasher = typename boost::type_identity<Hash>::type;
+      using key_equal = typename boost::type_identity<KeyEqual>::type;
+      using allocator_type = typename boost::type_identity<
+        typename boost::allocator_rebind<Allocator, value_type>::type>::type;
+      using reference = value_type&;
+      using const_reference = value_type const&;
+      using pointer = typename boost::allocator_pointer<allocator_type>::type;
+      using const_pointer =
+        typename boost::allocator_const_pointer<allocator_type>::type;
+      using iterator = boost::indirect_iterator<typename table_type::iterator>;
+      using const_iterator =
+        boost::indirect_iterator<typename table_type::const_iterator>;
+
+      unordered_node_map() : unordered_node_map(0) {}
+
+      explicit unordered_node_map(size_type n, hasher const& h = hasher(),
+        key_equal const& pred = key_equal(),
+        allocator_type const& a = allocator_type())
+          : table_(n, h, pred, detail::ptr_allocator_adaptor<allocator_type>(a))
+      {
+      }
+
+      unordered_node_map(size_type n, allocator_type const& a)
+          : unordered_node_map(n, hasher(), key_equal(), a)
+      {
+      }
+
+      unordered_node_map(size_type n, hasher const& h, allocator_type const& a)
+          : unordered_node_map(n, h, key_equal(), a)
+      {
+      }
+
+      template <class InputIterator>
+      unordered_node_map(
+        InputIterator f, InputIterator l, allocator_type const& a)
+          : unordered_node_map(f, l, size_type(0), hasher(), key_equal(), a)
+      {
+      }
+
+      explicit unordered_node_map(allocator_type const& a)
+          : unordered_node_map(0, a)
+      {
+      }
+
+      template <class Iterator>
+      unordered_node_map(Iterator first, Iterator last, size_type n = 0,
+        hasher const& h = hasher(), key_equal const& pred = key_equal(),
+        allocator_type const& a = allocator_type())
+          : unordered_node_map(n, h, pred, a)
+      {
+        this->insert(first, last);
+      }
+
+      template <class Iterator>
+      unordered_node_map(
+        Iterator first, Iterator last, size_type n, allocator_type const& a)
+          : unordered_node_map(first, last, n, hasher(), key_equal(), a)
+      {
+      }
+
+      template <class Iterator>
+      unordered_node_map(Iterator first, Iterator last, size_type n,
+        hasher const& h, allocator_type const& a)
+          : unordered_node_map(first, last, n, h, key_equal(), a)
+      {
+      }
+
+      unordered_node_map(unordered_node_map const& other) : table_(other.table_)
+      {
+      }
+
+      unordered_node_map(
+        unordered_node_map const& other, allocator_type const& a)
+          : table_(other.table_, a)
+      {
+      }
+
+      unordered_node_map(unordered_node_map&& other)
+        noexcept(std::is_nothrow_move_constructible<hasher>::value&&
+            std::is_nothrow_move_constructible<key_equal>::value&&
+              std::is_nothrow_move_constructible<allocator_type>::value)
+          : table_(std::move(other.table_))
+      {
+      }
+
+      unordered_node_map(unordered_node_map&& other, allocator_type const& al)
+          : table_(std::move(other.table_), al)
+      {
+      }
+
+      unordered_node_map(std::initializer_list<value_type> ilist,
+        size_type n = 0, hasher const& h = hasher(),
+        key_equal const& pred = key_equal(),
+        allocator_type const& a = allocator_type())
+          : unordered_node_map(ilist.begin(), ilist.end(), n, h, pred, a)
+      {
+      }
+
+      unordered_node_map(
+        std::initializer_list<value_type> il, allocator_type const& a)
+          : unordered_node_map(il, size_type(0), hasher(), key_equal(), a)
+      {
+      }
+
+      unordered_node_map(std::initializer_list<value_type> init, size_type n,
+        allocator_type const& a)
+          : unordered_node_map(init, n, hasher(), key_equal(), a)
+      {
+      }
+
+      unordered_node_map(std::initializer_list<value_type> init, size_type n,
+        hasher const& h, allocator_type const& a)
+          : unordered_node_map(init, n, h, key_equal(), a)
+      {
+      }
+
+      ~unordered_node_map() = default;
+
+      unordered_node_map& operator=(unordered_node_map const& other)
+      {
+        table_ = other.table_;
+        return *this;
+      }
+
+      unordered_node_map& operator=(unordered_node_map&& other) noexcept(
+        noexcept(std::declval<table_type&>() = std::declval<table_type&&>()))
+      {
+        table_ = std::move(other.table_);
+        return *this;
+      }
+
+      allocator_type get_allocator() const noexcept
+      {
+        return table_.get_allocator();
+      }
+
+      /// Iterators
+      ///
+
+      iterator begin() noexcept { return table_.begin(); }
+      const_iterator begin() const noexcept { return table_.begin(); }
+      const_iterator cbegin() const noexcept { return table_.cbegin(); }
+
+      iterator end() noexcept { return table_.end(); }
+      const_iterator end() const noexcept { return table_.end(); }
+      const_iterator cend() const noexcept { return table_.cend(); }
+
+      /// Capacity
+      ///
+
+      BOOST_ATTRIBUTE_NODISCARD bool empty() const noexcept
+      {
+        return table_.empty();
+      }
+
+      size_type size() const noexcept { return table_.size(); }
+
+      size_type max_size() const noexcept { return table_.max_size(); }
+
+      /// Modifiers
+      ///
+
+      void clear() noexcept { table_.clear(); }
+
+      template <class Ty>
+      BOOST_FORCEINLINE auto insert(Ty&& value)
+        -> decltype(table_.insert(std::forward<Ty>(value)))
+      {
+        return table_.try_emplace(std::forward<Ty>(value));
+      }
+
+      BOOST_FORCEINLINE std::pair<iterator, bool> insert(init_type&& value)
+      {
+        return table_.try_emplace(
+          std::move(value.first), std::move(value.second));
+      }
+
+      template <class Ty>
+      BOOST_FORCEINLINE auto insert(const_iterator, Ty&& value)
+        -> decltype(table_.insert(std::forward<Ty>(value)).first)
+      {
+        return table_.try_emplace(std::forward<Ty>(value)).first;
+      }
+
+      BOOST_FORCEINLINE iterator insert(const_iterator, init_type&& value)
+      {
+        return table_
+          .try_emplace(std::move(value.first), std::move(value.second))
+          .first;
+      }
+
+      template <class InputIterator>
+      BOOST_FORCEINLINE void insert(InputIterator first, InputIterator last)
+      {
+        for (auto pos = first; pos != last; ++pos) {
+          table_.emplace(*pos);
+        }
+      }
+
+      void insert(std::initializer_list<value_type> ilist)
+      {
+        this->insert(ilist.begin(), ilist.end());
+      }
+
+      template <class M>
+      std::pair<iterator, bool> insert_or_assign(key_type const& key, M&& obj)
+      {
+        auto iter_bool_pair = table_.try_emplace(key, std::forward<M>(obj));
+        if (iter_bool_pair.second) {
+          return iter_bool_pair;
+        }
+        (*(iter_bool_pair.first))->second = std::forward<M>(obj);
+        return iter_bool_pair;
+      }
+
+      template <class M>
+      std::pair<iterator, bool> insert_or_assign(key_type&& key, M&& obj)
+      {
+        auto iter_bool_pair =
+          table_.try_emplace(std::move(key), std::forward<M>(obj));
+        if (iter_bool_pair.second) {
+          return iter_bool_pair;
+        }
+        (*(iter_bool_pair.first))->second = std::forward<M>(obj);
+        return iter_bool_pair;
+      }
+
+      template <class M>
+      iterator insert_or_assign(const_iterator, key_type const& key, M&& obj)
+      {
+        return this->insert_or_assign(key, std::forward<M>(obj)).first;
+      }
+
+      template <class M>
+      iterator insert_or_assign(const_iterator, key_type&& key, M&& obj)
+      {
+        return this->insert_or_assign(std::move(key), std::forward<M>(obj))
+          .first;
+      }
+
+      template <class... Args>
+      BOOST_FORCEINLINE std::pair<iterator, bool> emplace(Args&&... args)
+      {
+        return table_.emplace(init_type(std::forward<Args>(args)...));
+      }
+
+      template <class... Args>
+      BOOST_FORCEINLINE iterator emplace_hint(const_iterator, Args&&... args)
+      {
+        return table_.emplace(std::forward<Args>(args)...).first;
+      }
+
+      template <class... Args>
+      BOOST_FORCEINLINE std::pair<iterator, bool> try_emplace(
+        key_type const& key, Args&&... args)
+      {
+        return table_.try_emplace(key, std::forward<Args>(args)...);
+      }
+
+      template <class... Args>
+      BOOST_FORCEINLINE std::pair<iterator, bool> try_emplace(
+        key_type&& key, Args&&... args)
+      {
+        return table_.try_emplace(std::move(key), std::forward<Args>(args)...);
+      }
+
+      template <class... Args>
+      BOOST_FORCEINLINE iterator try_emplace(
+        const_iterator, key_type const& key, Args&&... args)
+      {
+        return table_.try_emplace(key, std::forward<Args>(args)...).first;
+      }
+
+      template <class... Args>
+      BOOST_FORCEINLINE iterator try_emplace(
+        const_iterator, key_type&& key, Args&&... args)
+      {
+        return table_.try_emplace(std::move(key), std::forward<Args>(args)...)
+          .first;
+      }
+
+      BOOST_FORCEINLINE void erase(iterator pos) { table_.erase(pos); }
+      BOOST_FORCEINLINE void erase(const_iterator pos)
+      {
+        return table_.erase(pos);
+      }
+      iterator erase(const_iterator first, const_iterator last)
+      {
+        while (first != last) {
+          this->erase(first++);
+        }
+        return iterator{detail::foa::const_iterator_cast_tag{}, last};
+      }
+
+      BOOST_FORCEINLINE size_type erase(key_type const& key)
+      {
+        return table_.erase(key);
+      }
+
+      template <class K>
+      BOOST_FORCEINLINE typename std::enable_if<
+        detail::transparent_non_iterable<K, unordered_node_map>::value,
+        size_type>::type
+      erase(K const& key)
+      {
+        return table_.erase(key);
+      }
+
+      void swap(unordered_node_map& rhs) noexcept(
+        noexcept(std::declval<table_type&>().swap(std::declval<table_type&>())))
+      {
+        table_.swap(rhs.table_);
+      }
+
+      template <class H2, class P2>
+      void merge(
+        unordered_node_map<key_type, mapped_type, H2, P2, allocator_type>&
+          source)
+      {
+        table_.merge(source.table_);
+      }
+
+      template <class H2, class P2>
+      void merge(
+        unordered_node_map<key_type, mapped_type, H2, P2, allocator_type>&&
+          source)
+      {
+        table_.merge(std::move(source.table_));
+      }
+
+      /// Lookup
+      ///
+
+      mapped_type& at(key_type const& key)
+      {
+        auto pos = table_.find(key);
+        if (pos != table_.end()) {
+          return pos->second;
+        }
+        // TODO: someday refactor this to conditionally serialize the key and
+        // include it in the error message
+        //
+        boost::throw_exception(
+          std::out_of_range("key was not found in unordered_node_map"));
+      }
+
+      mapped_type const& at(key_type const& key) const
+      {
+        auto pos = table_.find(key);
+        if (pos != table_.end()) {
+          return pos->second;
+        }
+        boost::throw_exception(
+          std::out_of_range("key was not found in unordered_node_map"));
+      }
+
+      BOOST_FORCEINLINE mapped_type& operator[](key_type const& key)
+      {
+        return (*(table_.try_emplace(key).first))->second;
+      }
+
+      BOOST_FORCEINLINE mapped_type& operator[](key_type&& key)
+      {
+        return (*(table_.try_emplace(std::move(key)).first))->second;
+      }
+
+      BOOST_FORCEINLINE size_type count(key_type const& key) const
+      {
+        auto pos = table_.find(key);
+        return pos != table_.end() ? 1 : 0;
+      }
+
+      template <class K>
+      BOOST_FORCEINLINE typename std::enable_if<
+        detail::are_transparent<K, hasher, key_equal>::value, size_type>::type
+      count(K const& key) const
+      {
+        auto pos = table_.find(key);
+        return pos != table_.end() ? 1 : 0;
+      }
+
+      BOOST_FORCEINLINE iterator find(key_type const& key)
+      {
+        return table_.find(key);
+      }
+
+      BOOST_FORCEINLINE const_iterator find(key_type const& key) const
+      {
+        return table_.find(key);
+      }
+
+      template <class K>
+      BOOST_FORCEINLINE typename std::enable_if<
+        boost::unordered::detail::are_transparent<K, hasher, key_equal>::value,
+        iterator>::type
+      find(K const& key)
+      {
+        return table_.find(key);
+      }
+
+      template <class K>
+      BOOST_FORCEINLINE typename std::enable_if<
+        boost::unordered::detail::are_transparent<K, hasher, key_equal>::value,
+        const_iterator>::type
+      find(K const& key) const
+      {
+        return table_.find(key);
+      }
+
+      BOOST_FORCEINLINE bool contains(key_type const& key) const
+      {
+        return this->find(key) != this->end();
+      }
+
+      template <class K>
+      BOOST_FORCEINLINE typename std::enable_if<
+        boost::unordered::detail::are_transparent<K, hasher, key_equal>::value,
+        bool>::type
+      contains(K const& key) const
+      {
+        return this->find(key) != this->end();
+      }
+
+      std::pair<iterator, iterator> equal_range(key_type const& key)
+      {
+        auto pos = table_.find(key);
+        if (pos == table_.end()) {
+          return {pos, pos};
+        }
+
+        auto next = pos;
+        ++next;
+        return {pos, next};
+      }
+
+      std::pair<const_iterator, const_iterator> equal_range(
+        key_type const& key) const
+      {
+        auto pos = table_.find(key);
+        if (pos == table_.end()) {
+          return {pos, pos};
+        }
+
+        auto next = pos;
+        ++next;
+        return {pos, next};
+      }
+
+      template <class K>
+      typename std::enable_if<
+        detail::are_transparent<K, hasher, key_equal>::value,
+        std::pair<iterator, iterator> >::type
+      equal_range(K const& key)
+      {
+        auto pos = table_.find(key);
+        if (pos == table_.end()) {
+          return {pos, pos};
+        }
+
+        auto next = pos;
+        ++next;
+        return {pos, next};
+      }
+
+      template <class K>
+      typename std::enable_if<
+        detail::are_transparent<K, hasher, key_equal>::value,
+        std::pair<const_iterator, const_iterator> >::type
+      equal_range(K const& key) const
+      {
+        auto pos = table_.find(key);
+        if (pos == table_.end()) {
+          return {pos, pos};
+        }
+
+        auto next = pos;
+        ++next;
+        return {pos, next};
+      }
+
+      /// Hash Policy
+      ///
+
+      size_type bucket_count() const noexcept { return table_.capacity(); }
+
+      float load_factor() const noexcept { return table_.load_factor(); }
+
+      float max_load_factor() const noexcept
+      {
+        return table_.max_load_factor();
+      }
+
+      void max_load_factor(float) {}
+
+      size_type max_load() const noexcept { return table_.max_load(); }
+
+      void rehash(size_type n) { table_.rehash(n); }
+
+      void reserve(size_type n) { table_.reserve(n); }
+
+      /// Observers
+      ///
+
+      hasher hash_function() const { return table_.hash_function(); }
+
+      key_equal key_eq() const { return table_.key_eq(); }
+    };
+
+    template <class Key, class T, class Hash, class KeyEqual, class Allocator>
+    bool operator==(
+      unordered_node_map<Key, T, Hash, KeyEqual, Allocator> const& lhs,
+      unordered_node_map<Key, T, Hash, KeyEqual, Allocator> const& rhs)
+    {
+      if (&lhs == &rhs) {
+        return true;
+      }
+
+      return (lhs.size() == rhs.size()) && ([&] {
+        for (auto const& kvp : lhs) {
+          auto pos = rhs.find(kvp.first);
+          if ((pos == rhs.end()) || (*pos != kvp)) {
+            return false;
+          }
+        }
+        return true;
+      })();
+    }
+
+    template <class Key, class T, class Hash, class KeyEqual, class Allocator>
+    bool operator!=(
+      unordered_node_map<Key, T, Hash, KeyEqual, Allocator> const& lhs,
+      unordered_node_map<Key, T, Hash, KeyEqual, Allocator> const& rhs)
+    {
+      return !(lhs == rhs);
+    }
+
+    template <class Key, class T, class Hash, class KeyEqual, class Allocator>
+    void swap(unordered_node_map<Key, T, Hash, KeyEqual, Allocator>& lhs,
+      unordered_node_map<Key, T, Hash, KeyEqual, Allocator>& rhs)
+      noexcept(noexcept(lhs.swap(rhs)))
+    {
+      lhs.swap(rhs);
+    }
+
+    template <class Key, class T, class Hash, class KeyEqual, class Allocator,
+      class Pred>
+    typename unordered_node_map<Key, T, Hash, KeyEqual, Allocator>::size_type
+    erase_if(
+      unordered_node_map<Key, T, Hash, KeyEqual, Allocator>& map, Pred pred)
+    {
+      return erase_if(map.table_, pred);
+    }
+
+#if defined(BOOST_MSVC)
+#pragma warning(pop) /* C4714 */
+#endif
+
+#if BOOST_UNORDERED_TEMPLATE_DEDUCTION_GUIDES
+
+    namespace detail {
+      template <typename T>
+      using iter_key_t =
+        typename std::iterator_traits<T>::value_type::first_type;
+      template <typename T>
+      using iter_val_t =
+        typename std::iterator_traits<T>::value_type::second_type;
+      template <typename T>
+      using iter_to_alloc_t =
+        typename std::pair<iter_key_t<T> const, iter_val_t<T> >;
+    } // namespace detail
+
+    template <class InputIterator,
+      class Hash =
+        boost::hash<boost::unordered::detail::iter_key_t<InputIterator> >,
+      class Pred =
+        std::equal_to<boost::unordered::detail::iter_key_t<InputIterator> >,
+      class Allocator = std::allocator<
+        boost::unordered::detail::iter_to_alloc_t<InputIterator> >,
+      class = boost::enable_if_t<detail::is_input_iterator_v<InputIterator> >,
+      class = boost::enable_if_t<detail::is_hash_v<Hash> >,
+      class = boost::enable_if_t<detail::is_pred_v<Pred> >,
+      class = boost::enable_if_t<detail::is_allocator_v<Allocator> > >
+    unordered_node_map(InputIterator, InputIterator,
+      std::size_t = boost::unordered::detail::foa::default_bucket_count,
+      Hash = Hash(), Pred = Pred(), Allocator = Allocator())
+      -> unordered_node_map<boost::unordered::detail::iter_key_t<InputIterator>,
+        boost::unordered::detail::iter_val_t<InputIterator>, Hash, Pred,
+        Allocator>;
+
+    template <class Key, class T,
+      class Hash = boost::hash<boost::remove_const_t<Key> >,
+      class Pred = std::equal_to<boost::remove_const_t<Key> >,
+      class Allocator = std::allocator<std::pair<const Key, T> >,
+      class = boost::enable_if_t<detail::is_hash_v<Hash> >,
+      class = boost::enable_if_t<detail::is_pred_v<Pred> >,
+      class = boost::enable_if_t<detail::is_allocator_v<Allocator> > >
+    unordered_node_map(std::initializer_list<std::pair<Key, T> >,
+      std::size_t = boost::unordered::detail::foa::default_bucket_count,
+      Hash = Hash(), Pred = Pred(), Allocator = Allocator())
+      -> unordered_node_map<boost::remove_const_t<Key>, T, Hash, Pred,
+        Allocator>;
+
+    template <class InputIterator, class Allocator,
+      class = boost::enable_if_t<detail::is_input_iterator_v<InputIterator> >,
+      class = boost::enable_if_t<detail::is_allocator_v<Allocator> > >
+    unordered_node_map(InputIterator, InputIterator, std::size_t, Allocator)
+      -> unordered_node_map<boost::unordered::detail::iter_key_t<InputIterator>,
+        boost::unordered::detail::iter_val_t<InputIterator>,
+        boost::hash<boost::unordered::detail::iter_key_t<InputIterator> >,
+        std::equal_to<boost::unordered::detail::iter_key_t<InputIterator> >,
+        Allocator>;
+
+    template <class InputIterator, class Allocator,
+      class = boost::enable_if_t<detail::is_input_iterator_v<InputIterator> >,
+      class = boost::enable_if_t<detail::is_allocator_v<Allocator> > >
+    unordered_node_map(InputIterator, InputIterator, Allocator)
+      -> unordered_node_map<boost::unordered::detail::iter_key_t<InputIterator>,
+        boost::unordered::detail::iter_val_t<InputIterator>,
+        boost::hash<boost::unordered::detail::iter_key_t<InputIterator> >,
+        std::equal_to<boost::unordered::detail::iter_key_t<InputIterator> >,
+        Allocator>;
+
+    template <class InputIterator, class Hash, class Allocator,
+      class = boost::enable_if_t<detail::is_hash_v<Hash> >,
+      class = boost::enable_if_t<detail::is_input_iterator_v<InputIterator> >,
+      class = boost::enable_if_t<detail::is_allocator_v<Allocator> > >
+    unordered_node_map(
+      InputIterator, InputIterator, std::size_t, Hash, Allocator)
+      -> unordered_node_map<boost::unordered::detail::iter_key_t<InputIterator>,
+        boost::unordered::detail::iter_val_t<InputIterator>, Hash,
+        std::equal_to<boost::unordered::detail::iter_key_t<InputIterator> >,
+        Allocator>;
+
+    template <class Key, class T, class Allocator,
+      class = boost::enable_if_t<detail::is_allocator_v<Allocator> > >
+    unordered_node_map(std::initializer_list<std::pair<Key, T> >, std::size_t,
+      Allocator) -> unordered_node_map<boost::remove_const_t<Key>, T,
+      boost::hash<boost::remove_const_t<Key> >,
+      std::equal_to<boost::remove_const_t<Key> >, Allocator>;
+
+    template <class Key, class T, class Allocator,
+      class = boost::enable_if_t<detail::is_allocator_v<Allocator> > >
+    unordered_node_map(std::initializer_list<std::pair<Key, T> >, Allocator)
+      -> unordered_node_map<boost::remove_const_t<Key>, T,
+        boost::hash<boost::remove_const_t<Key> >,
+        std::equal_to<boost::remove_const_t<Key> >, Allocator>;
+
+    template <class Key, class T, class Hash, class Allocator,
+      class = boost::enable_if_t<detail::is_hash_v<Hash> >,
+      class = boost::enable_if_t<detail::is_allocator_v<Allocator> > >
+    unordered_node_map(std::initializer_list<std::pair<Key, T> >, std::size_t,
+      Hash, Allocator) -> unordered_node_map<boost::remove_const_t<Key>, T,
+      Hash, std::equal_to<boost::remove_const_t<Key> >, Allocator>;
+#endif
+
+  } // namespace unordered
+} // namespace boost
+
+#endif

include/boost/unordered/unordered_node_map_fwd.hpp

@@ -0,0 +1,49 @@
+
+// Copyright (C) 2022 Christian Mazakas
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+#ifndef BOOST_UNORDERED_NODE_MAP_FWD_HPP_INCLUDED
+#define BOOST_UNORDERED_NODE_MAP_FWD_HPP_INCLUDED
+
+#include <boost/config.hpp>
+#if defined(BOOST_HAS_PRAGMA_ONCE)
+#pragma once
+#endif
+
+#include <boost/functional/hash_fwd.hpp>
+#include <boost/unordered/detail/fwd.hpp>
+#include <functional>
+#include <memory>
+
+namespace boost {
+  namespace unordered {
+    template <class Key, class T, class Hash = boost::hash<Key>,
+      class KeyEqual = std::equal_to<Key>,
+      class Allocator = std::allocator<std::pair<const Key, T> > >
+    class unordered_node_map;
+
+    template <class Key, class T, class Hash, class KeyEqual, class Allocator>
+    bool operator==(
+      unordered_node_map<Key, T, Hash, KeyEqual, Allocator> const& lhs,
+      unordered_node_map<Key, T, Hash, KeyEqual, Allocator> const& rhs);
+
+    template <class Key, class T, class Hash, class KeyEqual, class Allocator>
+    bool operator!=(
+      unordered_node_map<Key, T, Hash, KeyEqual, Allocator> const& lhs,
+      unordered_node_map<Key, T, Hash, KeyEqual, Allocator> const& rhs);
+
+    template <class Key, class T, class Hash, class KeyEqual, class Allocator>
+    void swap(unordered_node_map<Key, T, Hash, KeyEqual, Allocator>& lhs,
+      unordered_node_map<Key, T, Hash, KeyEqual, Allocator>& rhs)
+      noexcept(noexcept(lhs.swap(rhs)));
+  } // namespace unordered
+
+  using boost::unordered::unordered_node_map;
+
+  using boost::unordered::swap;
+  using boost::unordered::operator==;
+  using boost::unordered::operator!=;
+} // namespace boost
+
+#endif

test/helpers/unordered.hpp

@@ -11,6 +11,7 @@
 #ifdef BOOST_UNORDERED_FOA_TESTS
 #include <boost/unordered/unordered_flat_set.hpp>
 #include <boost/unordered/unordered_flat_map.hpp>
+#include <boost/unordered/unordered_node_map.hpp>
 #include <boost/unordered/detail/implementation.hpp>
 #else
 #include <boost/unordered_set.hpp>

test/unordered/insert_tests.cpp

@@ -45,6 +45,7 @@ namespace insert_tests {
         float b = x.max_load_factor();
 
         std::pair<iterator, bool> r1 = x.insert(*it);
+        static_assert(std::is_same_v<decltype(*it), std::add_lvalue_reference_t<typename X::value_type>>);
         std::pair<typename ordered::iterator, bool> r2 = tracker.insert(*it);
 
         BOOST_TEST(r1.second == r2.second);
@@ -896,38 +897,41 @@ namespace insert_tests {
     test::allocator1<test::object> >* test_set;
   boost::unordered_flat_map<test::movable, test::movable, test::hash,
     test::equal_to, test::allocator2<test::movable> >* test_map;
+  boost::unordered_node_map<test::movable, test::movable, test::hash,
+    test::equal_to, test::allocator2<test::movable> >* test_node_map;
 
   UNORDERED_TEST(unique_insert_tests1,
-    ((test_set_std_alloc)(test_set)(test_map))(
+    ((test_set_std_alloc)(test_set)(test_map)(test_node_map))(
       (default_generator)(generate_collisions)(limited_range)))
 
   UNORDERED_TEST(
-    insert_tests2, ((test_set)(test_map))(
+    insert_tests2, ((test_set)(test_map)(test_node_map))(
                      (default_generator)(generate_collisions)(limited_range)))
 
   UNORDERED_TEST(unique_emplace_tests1,
-    ((test_set_std_alloc)(test_set)(test_map))(
+    ((test_set_std_alloc)(test_set)(test_map)(test_node_map))(
       (default_generator)(generate_collisions)(limited_range)))
 
   UNORDERED_TEST(move_emplace_tests,
-    ((test_set_std_alloc)(test_set)(test_map))(
+    ((test_set_std_alloc)(test_set)(test_map)(test_node_map))(
       (default_generator)(generate_collisions)(limited_range)))
 
   UNORDERED_TEST(default_emplace_tests,
-    ((test_set_std_alloc)(test_set)(test_map))(
+    ((test_set_std_alloc)(test_set)(test_map)(test_node_map))(
       (default_generator)(generate_collisions)(limited_range)))
 
   UNORDERED_TEST(map_tests,
-    ((test_map))((default_generator)(generate_collisions)(limited_range)))
+    ((test_map)(test_node_map))
+    ((default_generator)(generate_collisions)(limited_range)))
 
   UNORDERED_TEST(
-    map_tests2, ((test_map))((default_generator)(generate_collisions)))
+    map_tests2, ((test_map)(test_node_map))((default_generator)(generate_collisions)))
 
   UNORDERED_TEST(map_insert_range_test1,
-    ((test_map))((default_generator)(generate_collisions)(limited_range)))
+    ((test_map)(test_node_map))((default_generator)(generate_collisions)(limited_range)))
 
   UNORDERED_TEST(map_insert_range_test2,
-    ((test_map))((default_generator)(generate_collisions)(limited_range)))
+    ((test_map)(test_node_map))((default_generator)(generate_collisions)(limited_range)))
 
   UNORDERED_TEST(
     set_tests, ((test_set_std_alloc)(test_set))((default_generator)))