Merge pull request #238 from boostorg/fix/gh-237

Fixed bug in the `const` version of `unordered_multimap::find(k, hash, eq)`

.drone.jsonnet

@@ -102,16 +102,16 @@ local windows_pipeline(name, image, environment, arch = "amd64") =
 [
     linux_pipeline(
         "Linux 14.04 GCC 4.8* 32/64",
-        "cppalliance/droneubuntu1404:1",
-        { TOOLSET: 'gcc', COMPILER: 'g++', CXXSTD: '11', ADDRMD: '32,64' },
+        "cppalliance/droneubuntu1604:1",
+        { TOOLSET: 'gcc', COMPILER: 'g++-4.8', CXXSTD: '11', ADDRMD: '32,64' },
+        "g++-4.8-multilib",
     ),
 
     linux_pipeline(
         "Linux 14.04 GCC 4.9 32/64",
-        "cppalliance/droneubuntu1404:1",
+        "cppalliance/droneubuntu1604:1",
         { TOOLSET: 'gcc', COMPILER: 'g++-4.9', CXXSTD: '11', ADDRMD: '32,64' },
         "g++-4.9-multilib",
-        [ "ppa:ubuntu-toolchain-r/test" ],
     ),
 
     linux_pipeline(
@@ -468,7 +468,7 @@ local windows_pipeline(name, image, environment, arch = "amd64") =
     windows_pipeline(
         "Windows VS2015 msvc-14.0",
         "cppalliance/dronevs2015",
-        { TOOLSET: 'msvc-14.0', CXXSTD: '14,latest' },
+        { TOOLSET: 'msvc-14.0', CXXSTD: '14,latest', 'B2_DONT_EMBED_MANIFEST': 1 },
     ),
 
     windows_pipeline(
@@ -477,15 +477,33 @@ local windows_pipeline(name, image, environment, arch = "amd64") =
         { TOOLSET: 'msvc-14.1', CXXSTD: '14,17,latest' },
     ),
 
+    windows_pipeline(
+        "Windows VS2017 msvc-14.1 permissive-",
+        "cppalliance/dronevs2017",
+        { TOOLSET: 'msvc-14.1', CXXSTD: '14,17', CXXFLAGS: '/permissive-' },
+    ),
+
     windows_pipeline(
         "Windows VS2019 msvc-14.2",
         "cppalliance/dronevs2019",
         { TOOLSET: 'msvc-14.2', CXXSTD: '14,17,20,latest' },
     ),
 
+    windows_pipeline(
+        "Windows VS2019 msvc-14.2 permissive-",
+        "cppalliance/dronevs2019",
+        { TOOLSET: 'msvc-14.2', CXXSTD: '14,17', CXXFLAGS: '/permissive-' },
+    ),
+
     windows_pipeline(
         "Windows VS2022 msvc-14.3",
         "cppalliance/dronevs2022:1",
         { TOOLSET: 'msvc-14.3', CXXSTD: '14,17,20,latest' },
     ),
+
+    windows_pipeline(
+        "Windows VS2022 msvc-14.3 permissive-",
+        "cppalliance/dronevs2022:1",
+        { TOOLSET: 'msvc-14.3', CXXSTD: '14,17', CXXFLAGS: '/permissive-' },
+    ),
 ]

.drone/drone.bat

@@ -20,4 +20,5 @@ b2 -d0 headers
 
 if not "%CXXSTD%" == "" set CXXSTD=cxxstd=%CXXSTD%
 if not "%ADDRMD%" == "" set ADDRMD=address-model=%ADDRMD%
-b2 --abbreviate-paths -j3 libs/%LIBRARY%/test toolset=%TOOLSET% %CXXSTD% %ADDRMD% variant=debug,release embed-manifest-via=linker
+if not "%CXXFLAGS%" == "" set CXXFLAGS=cxxflags=%CXXFLAGS%
+b2 --abbreviate-paths -j3 libs/%LIBRARY%/test toolset=%TOOLSET% %CXXSTD% %ADDRMD% %CXXFLAGS% variant=debug,release embed-manifest-via=linker

.github/workflows/ci.yml

@@ -265,6 +265,7 @@ jobs:
           - { toolset: msvc-14.3, cxxstd: '14,17,20,latest', addrmd: '32,64', os: 'windows-2022', variant: 'debug,release' }
           - { toolset: msvc-14.3, cxxstd: '14',              addrmd: '64',    os: 'windows-2022', variant: 'debug', defines: '_ALLOW_RTCc_IN_STL', cxxflags: '/RTCc'              }
           - { toolset: msvc-14.3, cxxstd: '14',              addrmd: '32',    os: 'windows-2022', variant: 'debug', defines: '_ALLOW_RTCc_IN_STL', cxxflags: '"/RTCc /arch:IA32"' }
+          - { toolset: msvc-14.3, cxxstd: '14,17',           addrmd: '32,64', os: 'windows-2022', variant: 'debug,release', cxxflags: '/permissive-' }
           - { toolset: clang-win, cxxstd: '14,17,latest',    addrmd: '32,64', os: 'windows-2022', variant: 'debug,release' }
           - { toolset: gcc,       cxxstd: '11,14,17,2a',     addrmd: '64',    os: 'windows-2019', variant: 'debug,release' }
 

CMakeLists.txt

@@ -3,7 +3,7 @@
 # Distributed under the Boost Software License, Version 1.0.
 # https://www.boost.org/LICENSE_1_0.txt
 
-cmake_minimum_required(VERSION 3.5...3.20)
+cmake_minimum_required(VERSION 3.8...3.20)
 
 project(boost_unordered VERSION "${BOOST_SUPERPROJECT_VERSION}" LANGUAGES CXX)
 
@@ -18,16 +18,13 @@ target_link_libraries(boost_unordered
     Boost::config
     Boost::container_hash
     Boost::core
-    Boost::move
     Boost::mp11
     Boost::predef
-    Boost::preprocessor
-    Boost::static_assert
     Boost::throw_exception
-    Boost::tuple
-    Boost::type_traits
 )
 
+target_compile_features(boost_unordered INTERFACE cxx_std_11)
+
 if(BUILD_TESTING AND EXISTS "${CMAKE_CURRENT_SOURCE_DIR}/test/CMakeLists.txt")
 
   add_subdirectory(test)

doc/unordered/changes.adoc

@@ -6,6 +6,13 @@
 :github-pr-url: https://github.com/boostorg/unordered/pull
 :cpp: C++
 
+== Release 1.85.0
+
+* Optimized `emplace()` for a `value_type` or `init_type` (if applicable) argument to bypass creating an intermediate object. The argument is already the same type as the would-be intermediate object.
+* Optimized `emplace()` for `k,v` arguments on map containers to delay constructing the object until it is certain that an element should be inserted. This optimization happens when the map's `key_type` is move constructible or when the `k` argument is a `key_type`.
+* Fixed support for allocators with `explicit` copy constructors ({github-pr-url}/234[PR#234^]).
+* Fixed bug in the `const` version of `unordered_multimap::find(k, hash, eq)` ({github-pr-url}/238[PR#238^]).
+
 == Release 1.84.0 - Major update
 
 * Added `boost::concurrent_flat_set`.

doc/unordered/concurrent_flat_map.adoc

@@ -908,7 +908,9 @@ Inserts an object, constructed with the arguments `args`, in the table if and on
 Requires:;; `value_type` is constructible from `args`.
 Returns:;; `true` if an insert took place.
 Concurrency:;; Blocking on rehashing of `*this`.
-Notes:;; Invalidates pointers and references to elements if a rehashing is issued.
+Notes:;; Invalidates pointers and references to elements if a rehashing is issued. +
++
+If `args...` is of the form `k,v`, it delays constructing the whole object until it is certain that an element should be inserted, using only the `k` argument to check.
 
 ---
 

doc/unordered/copyright.adoc

@@ -11,8 +11,10 @@ Copyright (C) 2005-2008 Daniel James
 
 Copyright (C) 2022-2023 Christian Mazakas
 
-Copyright (C) 2022-2023 Joaquín M López Muñoz
+Copyright (C) 2022-2024 Joaquín M López Muñoz
 
 Copyright (C) 2022-2023 Peter Dimov
 
+Copyright (C) 2024 Braden Ganetsky
+
 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)

doc/unordered/hash_traits.adoc

@@ -38,7 +38,7 @@ Users can then declare a hash function `Hash` as avalanching either by embedding
 into the definition of `Hash`, or directly by specializing `hash_is_avalanching<Hash>` to a class with
 an embedded compile-time constant `value` set to `true`.
 
-xref:unordered_flat_set[`boost::unordered_flat_set`] and xref:unordered_flat_map[`boost::unordered_flat_map`]
+Open-addressing and concurrent containers
 use the provided hash function `Hash` as-is if `hash_is_avalanching<Hash>::value` is `true`; otherwise, they
 implement a bit-mixing post-processing stage to increase the quality of hashing at the expense of
 extra computational cost.

doc/unordered/structures.adoc

@@ -152,7 +152,7 @@ performing container-wide operations such as swapping or assignment.
 
 By using atomic operations to access the group metadata, lookup is (group-level)
 lock-free up to the point where an actual comparison needs to be done with an element
-that has been previously SIMD-matched: only then it's the group's spinlock used.
+that has been previously SIMD-matched: only then is the group's spinlock used.
 
 Insertion uses the following _optimistic algorithm_:
 

doc/unordered/unordered_flat_map.adoc

@@ -750,6 +750,8 @@ Returns:;; The `bool` component of the return type is `true` if an insert took p
 If an insert took place, then the iterator points to the newly inserted element. Otherwise, it points to the element with equivalent key.
 Throws:;; If an exception is thrown by an operation other than a call to `hasher` the function has no effect.
 Notes:;; Can invalidate iterators, pointers and references, but only if the insert causes the load to be greater than the maximum load. +
++
+If `args...` is of the form `k,v`, it delays constructing the whole object until it is certain that an element should be inserted, using only the `k` argument to check.
 
 ---
 
@@ -769,6 +771,8 @@ Returns:;; The `bool` component of the return type is `true` if an insert took p
 If an insert took place, then the iterator points to the newly inserted element. Otherwise, it points to the element with equivalent key.
 Throws:;; If an exception is thrown by an operation other than a call to `hasher` the function has no effect.
 Notes:;; Can invalidate iterators, pointers and references, but only if the insert causes the load to be greater than the maximum load. +
++
+If `args...` is of the form `k,v`, it delays constructing the whole object until it is certain that an element should be inserted, using only the `k` argument to check.
 
 ---
 

doc/unordered/unordered_map.adoc

@@ -797,7 +797,9 @@ If an insert took place, then the iterator points to the newly inserted element.
 Throws:;; If an exception is thrown by an operation other than a call to `hasher` the function has no effect.
 Notes:;; Can invalidate iterators, but only if the insert causes the load factor to be greater to or equal to the maximum load factor. +
 +
-Pointers and references to elements are never invalidated.
+Pointers and references to elements are never invalidated. +
++
+If `args...` is of the form `k,v`, it delays constructing the whole object until it is certain that an element should be inserted, using only the `k` argument to check. This optimization happens when the map's `key_type` is move constructible or when the `k` argument is a `key_type`.
 
 ---
 
@@ -818,7 +820,9 @@ Notes:;; The standard is fairly vague on the meaning of the hint. But the only p
 +
 Can invalidate iterators, but only if the insert causes the load factor to be greater to or equal to the maximum load factor. +
 +
-Pointers and references to elements are never invalidated.
+Pointers and references to elements are never invalidated. +
++
+If `args...` is of the form `k,v`, it delays constructing the whole object until it is certain that an element should be inserted, using only the `k` argument to check. This optimization happens when the map's `key_type` is move constructible or when the `k` argument is a `key_type`.
 
 ---
 

doc/unordered/unordered_node_map.adoc

@@ -767,6 +767,8 @@ Returns:;; The `bool` component of the return type is `true` if an insert took p
 If an insert took place, then the iterator points to the newly inserted element. Otherwise, it points to the element with equivalent key.
 Throws:;; If an exception is thrown by an operation other than a call to `hasher` the function has no effect.
 Notes:;; Can invalidate iterators, but only if the insert causes the load to be greater than the maximum load. +
++
+If `args...` is of the form `k,v`, it delays constructing the whole object until it is certain that an element should be inserted, using only the `k` argument to check. This optimization happens when `key_type` is move constructible or when the `k` argument is a `key_type`.
 
 ---
 
@@ -786,6 +788,8 @@ Returns:;; The `bool` component of the return type is `true` if an insert took p
 If an insert took place, then the iterator points to the newly inserted element. Otherwise, it points to the element with equivalent key.
 Throws:;; If an exception is thrown by an operation other than a call to `hasher` the function has no effect.
 Notes:;; Can invalidate iterators, but only if the insert causes the load to be greater than the maximum load. +
++
+If `args...` is of the form `k,v`, it delays constructing the whole object until it is certain that an element should be inserted, using only the `k` argument to check. This optimization happens when `key_type` is move constructible or when the `k` argument is a `key_type`.
 
 ---
 

include/boost/unordered/detail/allocator_constructed.hpp

@@ -0,0 +1,59 @@
+/* Copyright 2024 Braden Ganetsky.
+ * 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)
+ *
+ * See https://www.boost.org/libs/unordered for library home page.
+ */
+
+#ifndef BOOST_UNORDERED_DETAIL_ALLOCATOR_CONSTRUCTED_HPP
+#define BOOST_UNORDERED_DETAIL_ALLOCATOR_CONSTRUCTED_HPP
+
+#include <boost/core/allocator_traits.hpp>
+#include <boost/unordered/detail/opt_storage.hpp>
+
+namespace boost {
+  namespace unordered {
+    namespace detail {
+
+      struct allocator_policy
+      {
+        template <class Allocator, class T, class... Args>
+        static void construct(Allocator& a, T* p, Args&&... args)
+        {
+          boost::allocator_construct(a, p, std::forward<Args>(args)...);
+        }
+
+        template <class Allocator, class T>
+        static void destroy(Allocator& a, T* p)
+        {
+          boost::allocator_destroy(a, p);
+        }
+      };
+
+      /* constructs a stack-based object with the given policy and allocator */
+      template <class Allocator, class T, class Policy = allocator_policy>
+      class allocator_constructed
+      {
+        opt_storage<T> storage;
+        Allocator alloc;
+
+      public:
+        template <class... Args>
+        allocator_constructed(Allocator const& alloc_, Args&&... args)
+            : alloc(alloc_)
+        {
+          Policy::construct(
+            alloc, storage.address(), std::forward<Args>(args)...);
+        }
+
+        ~allocator_constructed() { Policy::destroy(alloc, storage.address()); }
+
+        T& value() { return *storage.address(); }
+      };
+
+    } /* namespace detail */
+  }   /* namespace unordered */
+} /* namespace boost */
+
+#endif

include/boost/unordered/detail/fca.hpp

@@ -1,4 +1,4 @@
-// Copyright (C) 2022-2023 Joaquin M Lopez Munoz.
+// Copyright (C) 2022-2024 Joaquin M Lopez Munoz.
 // Copyright (C) 2022 Christian Mazakas
 //
 // Distributed under the Boost Software License, Version 1.0. (See accompanying
@@ -518,7 +518,8 @@ namespace boost {
         }
 
         grouped_bucket_array(size_type n, const Allocator& al)
-            : empty_value<node_allocator_type>(empty_init_t(), al),
+            : empty_value<node_allocator_type>(
+                empty_init_t(), node_allocator_type(al)),
               size_index_(0), size_(0), buckets(), groups()
         {
           if (n == 0) {
@@ -678,12 +679,17 @@ namespace boost {
 
         bucket_allocator_type get_bucket_allocator() const
         {
-          return this->get_node_allocator();
+          return bucket_allocator_type(this->get_node_allocator());
         }
 
         group_allocator_type get_group_allocator() const
         {
-          return this->get_node_allocator();
+          return group_allocator_type(this->get_node_allocator());
+        }
+
+        Allocator get_allocator() const
+        {
+          return Allocator(this->get_node_allocator());
         }
 
         size_type buckets_len() const noexcept { return size_ + 1; }

include/boost/unordered/detail/foa/concurrent_table.hpp

@@ -1,6 +1,7 @@
 /* Fast open-addressing concurrent hash table.
  *
- * Copyright 2023 Joaquin M Lopez Munoz.
+ * Copyright 2023-2024 Joaquin M Lopez Munoz.
+ * Copyright 2024 Braden Ganetsky.
  * 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)
@@ -28,6 +29,7 @@
 #include <boost/unordered/detail/foa/tuple_rotate_right.hpp>
 #include <boost/unordered/detail/serialization_version.hpp>
 #include <boost/unordered/detail/static_assert.hpp>
+#include <boost/unordered/detail/type_traits.hpp>
 #include <cstddef>
 #include <functional>
 #include <initializer_list>
@@ -257,6 +259,7 @@ struct concurrent_table_arrays:table_arrays<Value,Group,SizePolicy,Allocator>
     typename boost::allocator_pointer<group_access_allocator_type>::type;
 
   using super=table_arrays<Value,Group,SizePolicy,Allocator>;
+  using allocator_type=typename super::allocator_type;
 
   concurrent_table_arrays(const super& arrays,group_access_pointer pga):
     super{arrays},group_accesses_{pga}{}
@@ -265,12 +268,11 @@ struct concurrent_table_arrays:table_arrays<Value,Group,SizePolicy,Allocator>
     return boost::to_address(group_accesses_);
   }
 
-  static concurrent_table_arrays new_(
-    group_access_allocator_type al,std::size_t n)
+  static concurrent_table_arrays new_(allocator_type al,std::size_t n)
   {
     super x{super::new_(al,n)};
     BOOST_TRY{
-      return new_group_access(al,x);
+      return new_group_access(group_access_allocator_type(al),x);
     }
     BOOST_CATCH(...){
       super::delete_(al,x);
@@ -320,10 +322,9 @@ struct concurrent_table_arrays:table_arrays<Value,Group,SizePolicy,Allocator>
     return arrays;
   }
 
-  static void delete_(
-    group_access_allocator_type al,concurrent_table_arrays& arrays)noexcept
+  static void delete_(allocator_type al,concurrent_table_arrays& arrays)noexcept
   {
-    delete_group_access(al,arrays);
+    delete_group_access(group_access_allocator_type(al),arrays);
     super::delete_(al,arrays);
   }
 
@@ -682,6 +683,26 @@ public:
     return construct_and_emplace(std::forward<Args>(args)...);
   }
 
+  /* Optimization for value_type and init_type, to avoid constructing twice */
+  template<typename Value>
+  BOOST_FORCEINLINE auto emplace(Value&& x)->typename std::enable_if<
+    detail::is_similar_to_any<Value,value_type,init_type>::value,bool>::type
+  {
+    return emplace_impl(std::forward<Value>(x));
+  }
+
+  /* Optimizations for maps for (k,v) to avoid eagerly constructing value */
+  template <typename K, typename V>
+  BOOST_FORCEINLINE auto emplace(K&& k, V&& v) ->
+    typename std::enable_if<is_emplace_kv_able<concurrent_table, K>::value,
+      bool>::type
+  {
+    alloc_cted_or_fwded_key_type<type_policy, Allocator, K&&> x(
+      this->al(), std::forward<K>(k));
+    return emplace_impl(
+      try_emplace_args_t{}, x.move_or_fwd(), std::forward<V>(v));
+  }
+
   BOOST_FORCEINLINE bool
   insert(const init_type& x){return emplace_impl(x);}
 
@@ -1311,7 +1332,7 @@ private:
   {
     auto lck=shared_access();
 
-    auto x=alloc_make_insert_type<type_policy>(
+    alloc_cted_insert_type<type_policy,Allocator,Args...> x(
       this->al(),std::forward<Args>(args)...);
     int res=unprotected_norehash_emplace_or_visit(
       access_mode,std::forward<F>(f),type_policy::move(x.value()));

include/boost/unordered/detail/foa/core.hpp

@@ -1,7 +1,8 @@
 /* Common base for Boost.Unordered open-addressing tables.
  *
- * Copyright 2022-2023 Joaquin M Lopez Munoz.
+ * Copyright 2022-2024 Joaquin M Lopez Munoz.
  * Copyright 2023 Christian Mazakas.
+ * Copyright 2024 Braden Ganetsky.
  * 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)
@@ -22,6 +23,7 @@
 #include <boost/core/pointer_traits.hpp>
 #include <boost/cstdint.hpp>
 #include <boost/predef.h>
+#include <boost/unordered/detail/allocator_constructed.hpp>
 #include <boost/unordered/detail/narrow_cast.hpp>
 #include <boost/unordered/detail/mulx.hpp>
 #include <boost/unordered/detail/static_assert.hpp>
@@ -975,7 +977,12 @@ struct arrays_holder
   arrays_holder(arrays_holder const&);
   arrays_holder& operator=(arrays_holder const&)=delete;
 
-  ~arrays_holder(){if(!released_)arrays_.delete_(al_,arrays_);}
+  ~arrays_holder()
+  {
+    if(!released_){
+      arrays_.delete_(typename Arrays::allocator_type(al_),arrays_);
+    }
+  }
 
   const Arrays& release()
   {
@@ -1220,22 +1227,15 @@ class alloc_cted_insert_type
     emplace_type,typename TypePolicy::element_type
   >::type;
 
-  alignas(insert_type) unsigned char storage[sizeof(insert_type)];
-  Allocator                          al;
+  using alloc_cted = allocator_constructed<Allocator, insert_type, TypePolicy>;
+  alloc_cted val;
 
 public:
-  alloc_cted_insert_type(const Allocator& al_,Args&&... args):al{al_}
+  alloc_cted_insert_type(const Allocator& al_,Args&&... args):val{al_,std::forward<Args>(args)...}
   {
-    TypePolicy::construct(al,data(),std::forward<Args>(args)...);
   }
 
-  ~alloc_cted_insert_type()
-  {
-    TypePolicy::destroy(al,data());
-  }
-
-  insert_type* data(){return reinterpret_cast<insert_type*>(&storage);}
-  insert_type& value(){return *data();}
+  insert_type& value(){return val.value();}
 };
 
 template<typename TypePolicy,typename Allocator,typename... Args>
@@ -1245,6 +1245,51 @@ alloc_make_insert_type(const Allocator& al,Args&&... args)
   return {al,std::forward<Args>(args)...};
 }
 
+template <typename TypePolicy, typename Allocator, typename KFwdRef,
+  typename = void>
+class alloc_cted_or_fwded_key_type
+{
+  using key_type = typename TypePolicy::key_type;
+  allocator_constructed<Allocator, key_type, TypePolicy> val;
+
+public:
+  alloc_cted_or_fwded_key_type(const Allocator& al_, KFwdRef k)
+      : val(al_, std::forward<KFwdRef>(k))
+  {
+  }
+
+  key_type&& move_or_fwd() { return std::move(val.value()); }
+};
+
+template <typename TypePolicy, typename Allocator, typename KFwdRef>
+class alloc_cted_or_fwded_key_type<TypePolicy, Allocator, KFwdRef,
+  typename std::enable_if<
+    is_similar<KFwdRef, typename TypePolicy::key_type>::value>::type>
+{
+  // This specialization acts as a forwarding-reference wrapper
+  BOOST_UNORDERED_STATIC_ASSERT(std::is_reference<KFwdRef>::value);
+  KFwdRef ref;
+
+public:
+  alloc_cted_or_fwded_key_type(const Allocator&, KFwdRef k)
+      : ref(std::forward<KFwdRef>(k))
+  {
+  }
+
+  KFwdRef move_or_fwd() { return std::forward<KFwdRef>(ref); }
+};
+
+template <typename Container>
+using is_map =
+  std::integral_constant<bool, !std::is_same<typename Container::key_type,
+                                 typename Container::value_type>::value>;
+
+template <typename Container, typename K>
+using is_emplace_kv_able = std::integral_constant<bool,
+  is_map<Container>::value &&
+    (is_similar<K, typename Container::key_type>::value ||
+      is_complete_and_move_constructible<typename Container::key_type>::value)>;
+
 /* table_core. The TypePolicy template parameter is used to generate
  * instantiations suitable for either maps or sets, and introduces non-standard
  * init_type and element_type:
@@ -1262,7 +1307,7 @@ alloc_make_insert_type(const Allocator& al,Args&&... args)
  *
  *   - TypePolicy::construct and TypePolicy::destroy are used for the
  *     construction and destruction of the internal types: value_type,
- *     init_type and element_type.
+ *     init_type, element_type, and key_type.
  * 
  *   - TypePolicy::move is used to provide move semantics for the internal
  *     types used by the container during rehashing and emplace. These types
@@ -1934,7 +1979,7 @@ private:
 
   arrays_type new_arrays(std::size_t n)const
   {
-    return arrays_type::new_(al(),n);
+    return arrays_type::new_(typename arrays_type::allocator_type(al()),n);
   }
 
   arrays_type new_arrays_for_growth()const
@@ -1955,7 +2000,7 @@ private:
 
   void delete_arrays(arrays_type& arrays_)noexcept
   {
-    arrays_type::delete_(al(),arrays_);
+    arrays_type::delete_(typename arrays_type::allocator_type(al()),arrays_);
   }
 
   arrays_holder_type make_arrays(std::size_t n)const

include/boost/unordered/detail/foa/flat_map_types.hpp

@@ -1,4 +1,5 @@
 // Copyright (C) 2023 Christian Mazakas
+// Copyright (C) 2024 Braden Ganetsky
 // 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)
 
@@ -56,6 +57,12 @@ namespace boost {
             boost::allocator_construct(al, p, std::forward<Args>(args)...);
           }
 
+          template <class A, class... Args>
+          static void construct(A& al, key_type* p, Args&&... args)
+          {
+            boost::allocator_construct(al, p, std::forward<Args>(args)...);
+          }
+
           template <class A> static void destroy(A& al, init_type* p) noexcept
           {
             boost::allocator_destroy(al, p);
@@ -65,6 +72,11 @@ namespace boost {
           {
             boost::allocator_destroy(al, p);
           }
+
+          template <class A> static void destroy(A& al, key_type* p) noexcept
+          {
+            boost::allocator_destroy(al, p);
+          }
         };
       } // namespace foa
     }   // namespace detail

include/boost/unordered/detail/foa/node_map_types.hpp

@@ -1,4 +1,5 @@
 // Copyright (C) 2023 Christian Mazakas
+// Copyright (C) 2024 Braden Ganetsky
 // 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)
 
@@ -82,6 +83,12 @@ namespace boost {
             boost::allocator_construct(al, p, std::forward<Args>(args)...);
           }
 
+          template <class A, class... Args>
+          static void construct(A& al, key_type* p, Args&&... args)
+          {
+            boost::allocator_construct(al, p, std::forward<Args>(args)...);
+          }
+
           template <class A, class... Args>
           static void construct(A& al, element_type* p, Args&&... args)
           {
@@ -109,6 +116,11 @@ namespace boost {
             boost::allocator_destroy(al, p);
           }
 
+          template <class A> static void destroy(A& al, key_type* p) noexcept
+          {
+            boost::allocator_destroy(al, p);
+          }
+
           template <class A>
           static void destroy(A& al, element_type* p) noexcept
           {

include/boost/unordered/detail/foa/table.hpp

@@ -2,6 +2,7 @@
  *
  * Copyright 2022-2023 Joaquin M Lopez Munoz.
  * Copyright 2023 Christian Mazakas.
+ * Copyright 2024 Braden Ganetsky.
  * 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)
@@ -18,6 +19,7 @@
 #include <boost/core/serialization.hpp>
 #include <boost/unordered/detail/foa/core.hpp>
 #include <boost/unordered/detail/serialize_tracked_address.hpp>
+#include <boost/unordered/detail/type_traits.hpp>
 #include <cstddef>
 #include <iterator>
 #include <memory>
@@ -400,11 +402,34 @@ public:
   template<typename... Args>
   BOOST_FORCEINLINE std::pair<iterator,bool> emplace(Args&&... args)
   {
-    auto x=alloc_make_insert_type<type_policy>(
+    alloc_cted_insert_type<type_policy,Allocator,Args...> x(
       this->al(),std::forward<Args>(args)...);
     return emplace_impl(type_policy::move(x.value()));
   }
 
+  /* Optimization for value_type and init_type, to avoid constructing twice */
+  template <typename T>
+  BOOST_FORCEINLINE typename std::enable_if<
+    detail::is_similar_to_any<T, value_type, init_type>::value,
+    std::pair<iterator, bool> >::type
+  emplace(T&& x)
+  {
+    return emplace_impl(std::forward<T>(x));
+  }
+
+  /* Optimizations for maps for (k,v) to avoid eagerly constructing value */
+  template <typename K, typename V>
+  BOOST_FORCEINLINE
+    typename std::enable_if<is_emplace_kv_able<table, K>::value,
+      std::pair<iterator, bool> >::type
+    emplace(K&& k, V&& v)
+  {
+    alloc_cted_or_fwded_key_type<type_policy, Allocator, K&&> x(
+      this->al(), std::forward<K>(k));
+    return emplace_impl(
+      try_emplace_args_t{}, x.move_or_fwd(), std::forward<V>(v));
+  }
+
   template<typename Key,typename... Args>
   BOOST_FORCEINLINE std::pair<iterator,bool> try_emplace(
     Key&& x,Args&&... args)

include/boost/unordered/detail/implementation.hpp

@@ -1,7 +1,8 @@
 // Copyright (C) 2003-2004 Jeremy B. Maitin-Shepard.
 // Copyright (C) 2005-2016 Daniel James
-// Copyright (C) 2022-2023 Joaquin M Lopez Munoz.
+// Copyright (C) 2022-2024 Joaquin M Lopez Munoz.
 // Copyright (C) 2022-2023 Christian Mazakas
+// Copyright (C) 2024 Braden Ganetsky
 //
 // 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)
@@ -14,6 +15,7 @@
 #pragma once
 #endif
 
+#include <boost/unordered/detail/allocator_constructed.hpp>
 #include <boost/unordered/detail/fca.hpp>
 #include <boost/unordered/detail/opt_storage.hpp>
 #include <boost/unordered/detail/serialize_tracked_address.hpp>
@@ -38,6 +40,7 @@
 #include <stdexcept>
 #include <type_traits>
 #include <utility>
+#include <tuple> // std::forward_as_tuple
 
 namespace boost {
   namespace tuples {
@@ -103,6 +106,10 @@ namespace boost {
         template <class T> no_key(T const&) {}
       };
 
+      struct converting_key
+      {
+      };
+
       namespace func {
         template <class T> inline void ignore_unused_variable_warning(T const&)
         {
@@ -1359,14 +1366,14 @@ namespace boost {
         }
 
         table(std::size_t num_buckets, hasher const& hf, key_equal const& eq,
-          node_allocator_type const& a)
+          value_allocator const& a)
             : functions(hf, eq), size_(0), mlf_(1.0f), max_load_(0),
               buckets_(num_buckets, a)
         {
           recalculate_max_load();
         }
 
-        table(table const& x, node_allocator_type const& a)
+        table(table const& x, value_allocator const& a)
             : functions(x), size_(0), mlf_(x.mlf_), max_load_(0),
               buckets_(x.size_, a)
         {
@@ -1381,7 +1388,7 @@ namespace boost {
           x.max_load_ = 0;
         }
 
-        table(table& x, node_allocator_type const& a,
+        table(table& x, value_allocator const& a,
           boost::unordered::detail::move_tag m)
             : functions(x, m), size_(0), mlf_(x.mlf_), max_load_(0),
               buckets_(x.bucket_count(), a)
@@ -1912,6 +1919,16 @@ namespace boost {
           }
         }
 
+        template <typename K, typename V>
+        emplace_return emplace_unique(converting_key, K&& k, V&& v)
+        {
+          using alloc_cted = allocator_constructed<node_allocator_type,
+            typename Types::key_type>;
+          alloc_cted key(this->node_alloc(), std::forward<K>(k));
+          return emplace_unique(
+            key.value(), std::move(key.value()), std::forward<V>(v));
+        }
+
         template <typename Key> emplace_return try_emplace_unique(Key&& k)
         {
           std::size_t key_hash = this->hash(k);
@@ -2705,7 +2722,7 @@ namespace boost {
       inline void table<Types>::rehash_impl(std::size_t num_buckets)
       {
         bucket_array_type new_buckets(
-          num_buckets, buckets_.get_node_allocator());
+          num_buckets, buckets_.get_allocator());
 
         BOOST_TRY
         {
@@ -2834,9 +2851,13 @@ namespace boost {
         }
 
         template <class Arg1, class Arg2>
-        static no_key extract(Arg1 const&, Arg2 const&)
+        static typename std::conditional<
+          (is_similar<Arg1, key_type>::value ||
+            is_complete_and_move_constructible<key_type>::value),
+          converting_key, no_key>::type
+        extract(Arg1 const&, Arg2 const&)
         {
-          return no_key();
+          return {};
         }
 
         template <class Arg1, class Arg2, class Arg3, class... Args>

include/boost/unordered/detail/map.hpp

@@ -1,6 +1,7 @@
 
 // Copyright (C) 2005-2016 Daniel James
 // Copyright (C) 2022 Christian Mazakas
+// Copyright (C) 2024 Braden Ganetsky
 // 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)
 
@@ -18,6 +19,7 @@ namespace boost {
         typedef std::pair<K const, M> value_type;
         typedef H hasher;
         typedef P key_equal;
+        typedef K key_type;
         typedef K const const_key_type;
 
         typedef

include/boost/unordered/detail/throw_exception.hpp

@@ -0,0 +1,30 @@
+// Copyright (C) 2023 Braden Ganetsky
+// 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_DETAIL_THROW_EXCEPTION_HPP
+#define BOOST_UNORDERED_DETAIL_THROW_EXCEPTION_HPP
+
+#include <boost/config.hpp>
+#if defined(BOOST_HAS_PRAGMA_ONCE)
+#pragma once
+#endif
+
+#include <boost/throw_exception.hpp>
+#include <stdexcept>
+
+namespace boost {
+  namespace unordered {
+    namespace detail {
+
+      BOOST_NOINLINE BOOST_NORETURN inline void throw_out_of_range(
+        char const* message)
+      {
+        boost::throw_exception(std::out_of_range(message));
+      }
+
+    } // namespace detail
+  } // namespace unordered
+} // namespace boost
+
+#endif // BOOST_UNORDERED_DETAIL_THROW_EXCEPTION_HPP

include/boost/unordered/detail/type_traits.hpp

@@ -1,4 +1,5 @@
 // Copyright (C) 2022-2023 Christian Mazakas
+// Copyright (C) 2024 Braden Ganetsky
 //
 // 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)
@@ -48,6 +49,20 @@ namespace boost {
 
       template <typename... Ts> using void_t = typename make_void<Ts...>::type;
 
+      template <class T, class = void> struct is_complete : std::false_type
+      {
+      };
+
+      template <class T>
+      struct is_complete<T, void_t<int[sizeof(T)]> > : std::true_type
+      {
+      };
+
+      template <class T>
+      using is_complete_and_move_constructible =
+        typename std::conditional<is_complete<T>::value,
+          std::is_move_constructible<T>, std::false_type>::type;
+
 #if BOOST_WORKAROUND(BOOST_LIBSTDCXX_VERSION, < 50000)
       /* std::is_trivially_default_constructible not provided */
       template <class T>
@@ -147,6 +162,23 @@ namespace boost {
           !std::is_convertible<Key, const_iterator>::value;
       };
 
+      template <class T>
+      using remove_cvref_t =
+        typename std::remove_cv<typename std::remove_reference<T>::type>::type;
+
+      template <class T, class U>
+      using is_similar = std::is_same<remove_cvref_t<T>, remove_cvref_t<U> >;
+
+      template <class, class...> struct is_similar_to_any : std::false_type
+      {
+      };
+      template <class T, class U, class... Us>
+      struct is_similar_to_any<T, U, Us...>
+          : std::conditional<is_similar<T, U>::value, is_similar<T, U>,
+              is_similar_to_any<T, Us...> >::type
+      {
+      };
+
 #if BOOST_UNORDERED_TEMPLATE_DEDUCTION_GUIDES
       // https://eel.is/c++draft/container.requirements#container.alloc.reqmts-34
       // https://eel.is/c++draft/container.requirements#unord.req.general-243

include/boost/unordered/unordered_flat_map.hpp

@@ -14,12 +14,12 @@
 #include <boost/unordered/detail/foa/flat_map_types.hpp>
 #include <boost/unordered/detail/foa/table.hpp>
 #include <boost/unordered/detail/serialize_container.hpp>
+#include <boost/unordered/detail/throw_exception.hpp>
 #include <boost/unordered/detail/type_traits.hpp>
 #include <boost/unordered/unordered_flat_map_fwd.hpp>
 
 #include <boost/core/allocator_access.hpp>
 #include <boost/container_hash/hash.hpp>
-#include <boost/throw_exception.hpp>
 
 #include <initializer_list>
 #include <iterator>
@@ -459,8 +459,8 @@ namespace boost {
         // 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_flat_map"));
+        boost::unordered::detail::throw_out_of_range(
+          "key was not found in unordered_flat_map");
       }
 
       mapped_type const& at(key_type const& key) const
@@ -469,8 +469,8 @@ namespace boost {
         if (pos != table_.end()) {
           return pos->second;
         }
-        boost::throw_exception(
-          std::out_of_range("key was not found in unordered_flat_map"));
+        boost::unordered::detail::throw_out_of_range(
+          "key was not found in unordered_flat_map");
       }
 
       template <class K>
@@ -483,8 +483,8 @@ namespace boost {
         if (pos != table_.end()) {
           return pos->second;
         }
-        boost::throw_exception(
-          std::out_of_range("key was not found in unordered_flat_map"));
+        boost::unordered::detail::throw_out_of_range(
+          "key was not found in unordered_flat_map");
       }
 
       template <class K>
@@ -497,8 +497,8 @@ namespace boost {
         if (pos != table_.end()) {
           return pos->second;
         }
-        boost::throw_exception(
-          std::out_of_range("key was not found in unordered_flat_map"));
+        boost::unordered::detail::throw_out_of_range(
+          "key was not found in unordered_flat_map");
       }
 
       BOOST_FORCEINLINE mapped_type& operator[](key_type const& key)

include/boost/unordered/unordered_map.hpp

@@ -1,6 +1,7 @@
 // Copyright (C) 2003-2004 Jeremy B. Maitin-Shepard.
 // Copyright (C) 2005-2011 Daniel James.
 // Copyright (C) 2022-2023 Christian Mazakas
+// Copyright (C) 2024 Joaquin M Lopez Munoz.
 // 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)
 
@@ -16,6 +17,7 @@
 
 #include <boost/unordered/detail/map.hpp>
 #include <boost/unordered/detail/serialize_fca_container.hpp>
+#include <boost/unordered/detail/throw_exception.hpp>
 #include <boost/unordered/detail/type_traits.hpp>
 
 #include <boost/container_hash/hash.hpp>
@@ -157,7 +159,7 @@ namespace boost {
 
       allocator_type get_allocator() const noexcept
       {
-        return table_.node_alloc();
+        return allocator_type(table_.node_alloc());
       }
 
       //       // iterators
@@ -253,12 +255,15 @@ namespace boost {
       node_type extract(const_iterator position)
       {
         return node_type(
-          table_.extract_by_iterator_unique(position), table_.node_alloc());
+          table_.extract_by_iterator_unique(position),
+          allocator_type(table_.node_alloc()));
       }
 
       node_type extract(const key_type& k)
       {
-        return node_type(table_.extract_by_key_impl(k), table_.node_alloc());
+        return node_type(
+          table_.extract_by_key_impl(k),
+          allocator_type(table_.node_alloc()));
       }
 
       template <class Key>
@@ -267,8 +272,9 @@ namespace boost {
         node_type>::type
       extract(Key&& k)
       {
-        return node_type(table_.extract_by_key_impl(std::forward<Key>(k)),
-          table_.node_alloc());
+        return node_type(
+          table_.extract_by_key_impl(std::forward<Key>(k)),
+          allocator_type(table_.node_alloc()));
       }
 
       insert_return_type insert(node_type&& np)
@@ -805,7 +811,7 @@ namespace boost {
 
       allocator_type get_allocator() const noexcept
       {
-        return table_.node_alloc();
+        return allocator_type(table_.node_alloc());
       }
 
       // iterators
@@ -1586,8 +1592,8 @@ namespace boost {
           return p->value().second;
       }
 
-      boost::throw_exception(
-        std::out_of_range("Unable to find key in unordered_map."));
+      boost::unordered::detail::throw_out_of_range(
+        "Unable to find key in unordered_map.");
     }
 
     template <class K, class T, class H, class P, class A>
@@ -1602,8 +1608,8 @@ namespace boost {
           return p->value().second;
       }
 
-      boost::throw_exception(
-        std::out_of_range("Unable to find key in unordered_map."));
+      boost::unordered::detail::throw_out_of_range(
+        "Unable to find key in unordered_map.");
     }
 
     template <class K, class T, class H, class P, class A>
@@ -1620,8 +1626,8 @@ namespace boost {
           return p->value().second;
       }
 
-      boost::throw_exception(
-        std::out_of_range("Unable to find key in unordered_map."));
+      boost::unordered::detail::throw_out_of_range(
+        "Unable to find key in unordered_map.");
     }
 
     template <class K, class T, class H, class P, class A>
@@ -1638,8 +1644,8 @@ namespace boost {
           return p->value().second;
       }
 
-      boost::throw_exception(
-        std::out_of_range("Unable to find key in unordered_map."));
+      boost::unordered::detail::throw_out_of_range(
+        "Unable to find key in unordered_map.");
     }
 
     template <class K, class T, class H, class P, class A>
@@ -2051,8 +2057,7 @@ namespace boost {
     unordered_multimap<K, T, H, P, A>::find(CompatibleKey const& k,
       CompatibleHash const& hash, CompatiblePredicate const& eq) const
     {
-      return const_iterator(
-        table_.find_node_impl(table::policy::apply_hash(hash, k), k, eq));
+      return table_.transparent_find(k, hash, eq);
     }
 
     template <class K, class T, class H, class P, class A>

include/boost/unordered/unordered_node_map.hpp

@@ -15,12 +15,12 @@
 #include <boost/unordered/detail/foa/node_map_types.hpp>
 #include <boost/unordered/detail/foa/table.hpp>
 #include <boost/unordered/detail/serialize_container.hpp>
+#include <boost/unordered/detail/throw_exception.hpp>
 #include <boost/unordered/detail/type_traits.hpp>
 #include <boost/unordered/unordered_node_map_fwd.hpp>
 
 #include <boost/core/allocator_access.hpp>
 #include <boost/container_hash/hash.hpp>
-#include <boost/throw_exception.hpp>
 
 #include <initializer_list>
 #include <iterator>
@@ -554,8 +554,8 @@ namespace boost {
         // 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"));
+        boost::unordered::detail::throw_out_of_range(
+          "key was not found in unordered_node_map");
       }
 
       mapped_type const& at(key_type const& key) const
@@ -564,8 +564,8 @@ namespace boost {
         if (pos != table_.end()) {
           return pos->second;
         }
-        boost::throw_exception(
-          std::out_of_range("key was not found in unordered_node_map"));
+        boost::unordered::detail::throw_out_of_range(
+          "key was not found in unordered_node_map");
       }
 
       template <class K>
@@ -578,8 +578,8 @@ namespace boost {
         if (pos != table_.end()) {
           return pos->second;
         }
-        boost::throw_exception(
-          std::out_of_range("key was not found in unordered_node_map"));
+        boost::unordered::detail::throw_out_of_range(
+          "key was not found in unordered_node_map");
       }
 
       template <class K>
@@ -592,8 +592,8 @@ namespace boost {
         if (pos != table_.end()) {
           return pos->second;
         }
-        boost::throw_exception(
-          std::out_of_range("key was not found in unordered_node_map"));
+        boost::unordered::detail::throw_out_of_range(
+          "key was not found in unordered_node_map");
       }
 
       BOOST_FORCEINLINE mapped_type& operator[](key_type const& key)

include/boost/unordered/unordered_set.hpp

@@ -1,6 +1,7 @@
 // Copyright (C) 2003-2004 Jeremy B. Maitin-Shepard.
 // Copyright (C) 2005-2011 Daniel James.
 // Copyright (C) 2022-2023 Christian Mazakas
+// Copyright (C) 2024 Joaquin M Lopez Munoz.
 // 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)
 
@@ -154,7 +155,7 @@ namespace boost {
 
       allocator_type get_allocator() const noexcept
       {
-        return table_.node_alloc();
+        return allocator_type(table_.node_alloc());
       }
 
       // iterators
@@ -252,12 +253,15 @@ namespace boost {
       node_type extract(const_iterator position)
       {
         return node_type(
-          table_.extract_by_iterator_unique(position), table_.node_alloc());
+          table_.extract_by_iterator_unique(position),
+          allocator_type(table_.node_alloc()));
       }
 
       node_type extract(const key_type& k)
       {
-        return node_type(table_.extract_by_key_impl(k), table_.node_alloc());
+        return node_type(
+          table_.extract_by_key_impl(k),
+          allocator_type(table_.node_alloc()));
       }
 
       template <class Key>
@@ -266,7 +270,9 @@ namespace boost {
         node_type>::type
       extract(const Key& k)
       {
-        return node_type(table_.extract_by_key_impl(k), table_.node_alloc());
+        return node_type(
+          table_.extract_by_key_impl(k),
+          allocator_type(table_.node_alloc()));
       }
 
       insert_return_type insert(node_type&& np)
@@ -647,7 +653,7 @@ namespace boost {
 
       allocator_type get_allocator() const noexcept
       {
-        return table_.node_alloc();
+        return allocator_type(table_.node_alloc());
       }
 
       // iterators

test/CMakeLists.txt

@@ -9,7 +9,7 @@ if(HAVE_BOOST_TEST)
 set(THREADS_PREFER_PTHREAD_FLAG ON)
 find_package(Threads REQUIRED)
 
-set(BOOST_TEST_LINK_LIBRARIES Boost::unordered Boost::core Boost::concept_check)
+set(BOOST_TEST_LINK_LIBRARIES Boost::unordered Boost::core Boost::concept_check Boost::tuple)
 
 function(fca_tests)
   boost_test(PREFIX boost_unordered ${ARGN})

test/Jamfile.v2

@@ -85,12 +85,14 @@ local FCA_TESTS =
   contains_tests
   copy_tests
   deduction_tests
+  emplace_smf_tests
   emplace_tests
   equality_tests
   equivalent_keys_tests
   erase_equiv_tests
   erase_if
   erase_tests
+  explicit_alloc_ctor_tests
   extract_tests
   find_tests
   fwd_map_test
@@ -201,8 +203,10 @@ local FOA_TESTS =
   assign_tests
   insert_tests
   insert_hint_tests
+  emplace_smf_tests
   emplace_tests
   erase_tests
+  explicit_alloc_ctor_tests
   merge_tests
   find_tests
   at_tests
@@ -325,6 +329,7 @@ local CFOA_TESTS =
   rw_spinlock_test7
   rw_spinlock_test8
   reentrancy_check_test
+  explicit_alloc_ctor_tests
 ;
 
 for local test in $(CFOA_TESTS)

test/cfoa/assign_tests.cpp

@@ -968,11 +968,9 @@ namespace {
       BOOST_TEST_EQ(x.key_eq(), key_equal(2));
 
       BOOST_TEST_EQ(
-        raii::copy_constructor, value_type_cardinality * values.size());
-      BOOST_TEST_EQ(
-        raii::destructor, value_type_cardinality * values.size());
-      BOOST_TEST_EQ(
-        raii::move_constructor, value_type_cardinality * reference_cont.size());
+        raii::copy_constructor, value_type_cardinality * reference_cont.size());
+      BOOST_TEST_EQ(raii::destructor, 0u);
+      BOOST_TEST_EQ(raii::move_constructor, 0u);
       BOOST_TEST_EQ(raii::copy_assignment, 0u);
       BOOST_TEST_EQ(raii::move_assignment, 0u);
     }
@@ -998,11 +996,9 @@ namespace {
       BOOST_TEST_EQ(flat.key_eq(), key_equal(2));
 
       BOOST_TEST_EQ(
-        raii::copy_constructor, value_type_cardinality * values.size());
-      BOOST_TEST_EQ(
-        raii::destructor, value_type_cardinality * values.size());
-      BOOST_TEST_EQ(
-        raii::move_constructor, value_type_cardinality * reference_cont.size());
+        raii::copy_constructor, value_type_cardinality * reference_cont.size());
+      BOOST_TEST_EQ(raii::destructor, 0u);
+      BOOST_TEST_EQ(raii::move_constructor, 0u);
       BOOST_TEST_EQ(raii::copy_assignment, 0u);
       BOOST_TEST_EQ(raii::move_assignment, 0u);
     }
@@ -1030,14 +1026,11 @@ namespace {
       BOOST_TEST_EQ(x.key_eq(), key_equal(2));
 
       BOOST_TEST_EQ(
-        raii::copy_constructor, value_type_cardinality * values.size());
+        raii::copy_constructor, value_type_cardinality * reference_cont.size());
       BOOST_TEST_EQ(
-        raii::destructor,
-        value_type_cardinality * values.size() + 
-        value_type_cardinality * reference_cont.size());
+        raii::destructor, value_type_cardinality * reference_cont.size());
       BOOST_TEST_EQ(
-        raii::move_constructor,
-        2 * value_type_cardinality * reference_cont.size());
+        raii::move_constructor, value_type_cardinality * reference_cont.size());
       BOOST_TEST_EQ(raii::copy_assignment, 0u);
       BOOST_TEST_EQ(raii::move_assignment, 0u);
     }
@@ -1063,14 +1056,11 @@ namespace {
       BOOST_TEST_EQ(flat.key_eq(), key_equal(2));
 
       BOOST_TEST_EQ(
-        raii::copy_constructor, value_type_cardinality * values.size());
+        raii::copy_constructor, value_type_cardinality * reference_cont.size());
       BOOST_TEST_EQ(
-        raii::destructor,
-        value_type_cardinality * values.size() +
-        value_type_cardinality * reference_cont.size());
+        raii::destructor, value_type_cardinality * reference_cont.size());
       BOOST_TEST_EQ(
-        raii::move_constructor, 
-        2 * value_type_cardinality * reference_cont.size());
+        raii::move_constructor, value_type_cardinality * reference_cont.size());
       BOOST_TEST_EQ(raii::copy_assignment, 0u);
       BOOST_TEST_EQ(raii::move_assignment, 0u);
     }

test/cfoa/constructor_tests.cpp

@@ -712,9 +712,9 @@ namespace {
 
       BOOST_TEST_EQ(raii::default_constructor, 0u);
       BOOST_TEST_EQ(
-        raii::copy_constructor, value_type_cardinality * init_list.size());
+        raii::copy_constructor, value_type_cardinality * init_list.size() / 2u);
       BOOST_TEST_EQ(
-        raii::move_constructor, value_type_cardinality * 11u);
+        raii::move_constructor, 0u);
     }
     check_raii_counts();
 
@@ -730,9 +730,9 @@ namespace {
 
       BOOST_TEST_EQ(raii::default_constructor, 0u);
       BOOST_TEST_EQ(
-        raii::copy_constructor, value_type_cardinality * init_list.size());
+        raii::copy_constructor, value_type_cardinality * init_list.size() / 2u);
       BOOST_TEST_EQ(
-        raii::move_constructor, value_type_cardinality * 11u);
+        raii::move_constructor, 0u);
     }
     check_raii_counts();
 
@@ -748,9 +748,9 @@ namespace {
 
       BOOST_TEST_EQ(raii::default_constructor, 0u);
       BOOST_TEST_EQ(
-        raii::copy_constructor, value_type_cardinality * init_list.size());
+        raii::copy_constructor, value_type_cardinality * init_list.size() / 2u);
       BOOST_TEST_EQ(
-        raii::move_constructor, value_type_cardinality * 11u);
+        raii::move_constructor, 0u);
     }
     check_raii_counts();
 
@@ -766,9 +766,9 @@ namespace {
 
       BOOST_TEST_EQ(raii::default_constructor, 0u);
       BOOST_TEST_EQ(
-        raii::copy_constructor, value_type_cardinality * init_list.size());
+        raii::copy_constructor, value_type_cardinality * init_list.size() / 2u);
       BOOST_TEST_EQ(
-        raii::move_constructor, value_type_cardinality * 11u);
+        raii::move_constructor, 0u);
     }
     check_raii_counts();
   }
@@ -867,6 +867,9 @@ namespace {
   template <class X, class GF>
   void flat_constructor(X*, GF gen_factory, test::random_generator rg)
   {
+    using value_type = typename X::value_type;
+    static constexpr auto value_type_cardinality =
+      value_cardinality<value_type>::value;
     using allocator_type = typename X::allocator_type;
 
     auto gen = gen_factory.template get<X>();
@@ -886,8 +889,8 @@ namespace {
       auto const old_cc = +raii::copy_constructor;
 
       BOOST_TEST_EQ(old_dc, 0u);
-      BOOST_TEST_GT(old_mc, 0u);
-      BOOST_TEST_GT(old_cc, 0u);
+      BOOST_TEST_EQ(old_mc, 0u);
+      BOOST_TEST_EQ(old_cc, value_type_cardinality * flat.size());
 
       X x(std::move(flat));
 
@@ -931,8 +934,8 @@ namespace {
       auto const old_cc = +raii::copy_constructor;
 
       BOOST_TEST_EQ(old_dc, 0u);
-      BOOST_TEST_GT(old_mc, 0u);
-      BOOST_TEST_GT(old_cc, 0u);
+      BOOST_TEST_EQ(old_mc, 0u);
+      BOOST_TEST_EQ(old_cc, 2u * value_type_cardinality * x.size());
 
       flat_container<X> flat(std::move(x));
 

test/cfoa/emplace_tests.cpp

@@ -1,9 +1,11 @@
 // Copyright (C) 2023 Christian Mazakas
 // Copyright (C) 2023 Joaquin M Lopez Munoz
+// Copyright (C) 2024 Braden Ganetsky
 // 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)
 
 #include "helpers.hpp"
+#include "../helpers/count.hpp"
 
 #include <boost/unordered/concurrent_flat_map.hpp>
 #include <boost/unordered/concurrent_flat_set.hpp>
@@ -51,7 +53,7 @@ namespace {
 
   struct lvalue_emplacer_type
   {
-    template <class T, class X> void operator()(std::vector<T>& values, X& x)
+    template <class T, class X> void call_impl(std::vector<T>& values, X& x)
     {
       static constexpr auto value_type_cardinality = 
         value_cardinality<typename X::value_type>::value;
@@ -66,28 +68,33 @@ namespace {
         }
       });
       BOOST_TEST_EQ(num_inserts, x.size());
-      BOOST_TEST_EQ(
-        raii::default_constructor, value_type_cardinality * values.size());
 
-      BOOST_TEST_EQ(raii::copy_constructor, 0u);
-      BOOST_TEST_GE(raii::move_constructor, value_type_cardinality * x.size());
+      std::uint64_t const default_constructors = value_type_cardinality == 2
+                                                   ? values.size() + num_inserts
+                                                   : values.size();
+      BOOST_TEST_EQ(raii::default_constructor, default_constructors);
 
       BOOST_TEST_EQ(raii::copy_constructor, 0u);
       BOOST_TEST_EQ(raii::copy_assignment, 0u);
       BOOST_TEST_EQ(raii::move_assignment, 0u);
     }
+    template <class T, class X> void operator()(std::vector<T>& values, X& x)
+    {
+      static constexpr auto value_type_cardinality =
+        value_cardinality<typename X::value_type>::value;
+
+      call_impl(values, x);
+      BOOST_TEST_GE(raii::move_constructor, value_type_cardinality * x.size());
+    }
   } lvalue_emplacer;
 
   struct norehash_lvalue_emplacer_type : public lvalue_emplacer_type
   {
     template <class T, class X> void operator()(std::vector<T>& values, X& x)
     {
-      static constexpr auto value_type_cardinality = 
-        value_cardinality<typename X::value_type>::value;
-
       x.reserve(values.size());
-      lvalue_emplacer_type::operator()(values, x);
-      BOOST_TEST_EQ(raii::move_constructor, value_type_cardinality * x.size());
+      lvalue_emplacer_type::call_impl(values, x);
+      BOOST_TEST_EQ(raii::move_constructor, x.size());
     }
   } norehash_lvalue_emplacer;
 
@@ -170,6 +177,74 @@ namespace {
     }
   } lvalue_emplace_or_visit;
 
+  struct copy_emplacer_type
+  {
+    template <class T, class X> void operator()(std::vector<T>& values, X& x)
+    {
+      static constexpr auto value_type_cardinality =
+        value_cardinality<typename X::value_type>::value;
+
+      std::atomic<std::uint64_t> num_inserts{0};
+      thread_runner(values, [&x, &num_inserts](boost::span<T> s) {
+        for (auto const& r : s) {
+          bool b = x.emplace(r);
+          if (b) {
+            ++num_inserts;
+          }
+        }
+      });
+      BOOST_TEST_EQ(num_inserts, x.size());
+      BOOST_TEST_EQ(raii::default_constructor, 0u);
+
+      BOOST_TEST_EQ(raii::copy_constructor, value_type_cardinality * x.size());
+      BOOST_TEST_GT(raii::move_constructor, 0u);
+
+      BOOST_TEST_EQ(raii::copy_assignment, 0u);
+      BOOST_TEST_EQ(raii::move_assignment, 0u);
+    }
+  } copy_emplacer;
+
+  struct move_emplacer_type
+  {
+    template <class T, class X> void operator()(std::vector<T>& values, X& x)
+    {
+      static constexpr auto value_type_cardinality =
+        value_cardinality<typename X::value_type>::value;
+
+      std::atomic<std::uint64_t> num_inserts{0};
+      thread_runner(values, [&x, &num_inserts](boost::span<T> s) {
+        for (auto& r : s) {
+          bool b = x.emplace(std::move(r));
+          if (b) {
+            ++num_inserts;
+          }
+        }
+      });
+      BOOST_TEST_EQ(num_inserts, x.size());
+      BOOST_TEST_EQ(raii::default_constructor, 0u);
+
+#if defined(BOOST_MSVC)
+#pragma warning(push)
+#pragma warning(disable : 4127) // conditional expression is constant
+#endif
+      if (std::is_same<T, typename X::value_type>::value &&
+          !std::is_same<typename X::key_type,
+            typename X::value_type>::value) { // map value_type can only be
+                                              // copied, no move
+        BOOST_TEST_EQ(raii::copy_constructor, x.size());
+      } else {
+        BOOST_TEST_EQ(raii::copy_constructor, 0u);
+      }
+#if defined(BOOST_MSVC)
+#pragma warning(pop) // C4127
+#endif
+      BOOST_TEST_GT(raii::move_constructor, value_type_cardinality * x.size());
+
+      BOOST_TEST_EQ(raii::copy_assignment, 0u);
+      BOOST_TEST_EQ(raii::move_assignment, 0u);
+    }
+  } move_emplacer;
+
   template <class X, class GF, class F>
   void emplace(X*, GF gen_factory, F emplacer, test::random_generator rg)
   {
@@ -220,9 +295,179 @@ UNORDERED_TEST(
   ((map)(set))
   ((value_type_generator_factory)(init_type_generator_factory))
   ((lvalue_emplacer)(norehash_lvalue_emplacer)
-   (lvalue_emplace_or_cvisit)(lvalue_emplace_or_visit))
+   (lvalue_emplace_or_cvisit)(lvalue_emplace_or_visit)(copy_emplacer)(move_emplacer))
   ((default_generator)(sequential)(limited_range)))
 
 // clang-format on
 
+namespace {
+  using converting_key_type = basic_raii<struct converting_key_tag_>;
+  using converting_value_type = basic_raii<struct converting_value_tag_>;
+
+  class counted_key_type : public basic_raii<struct counted_key_tag_>
+  {
+  public:
+    using basic_raii::basic_raii;
+    counted_key_type() = default;
+    counted_key_type(const converting_key_type& k) : counted_key_type(k.x_) {}
+  };
+  class counted_value_type : public basic_raii<struct counted_value_tag_>
+  {
+  public:
+    using basic_raii::basic_raii;
+    counted_value_type() = default;
+    counted_value_type(const converting_value_type& v)
+        : counted_value_type(v.x_)
+    {
+    }
+  };
+
+  void reset_counts()
+  {
+    counted_key_type::reset_counts();
+    counted_value_type::reset_counts();
+    converting_key_type::reset_counts();
+    converting_value_type::reset_counts();
+  }
+
+  using test::smf_count;
+
+  template <class T> smf_count count_for()
+  {
+    return test::smf_count{
+      (int)T::default_constructor.load(std::memory_order_relaxed),
+      (int)T::copy_constructor.load(std::memory_order_relaxed),
+      (int)T::move_constructor.load(std::memory_order_relaxed),
+      (int)T::copy_assignment.load(std::memory_order_relaxed),
+      (int)T::move_assignment.load(std::memory_order_relaxed),
+      (int)T::destructor.load(std::memory_order_relaxed)};
+  }
+
+  enum emplace_kind
+  {
+    copy,
+    move
+  };
+
+  enum emplace_status
+  {
+    fail,
+    success
+  };
+
+  struct counted_key_checker_type
+  {
+    using key_type = counted_key_type;
+    void operator()(emplace_kind kind, emplace_status status)
+    {
+      int copies = (kind == copy && status == success) ? 1 : 0;
+      int moves = (kind == move && status == success) ? 1 : 0;
+      BOOST_TEST_EQ(
+        count_for<counted_key_type>(), (smf_count{0, copies, moves, 0, 0, 0}));
+    }
+  } counted_key_checker;
+
+  struct converting_key_checker_type
+  {
+    using key_type = converting_key_type;
+    void operator()(emplace_kind, emplace_status status)
+    {
+      int moves = (status == success) ? 1 : 0;
+      BOOST_TEST_EQ(
+        count_for<counted_key_type>(), (smf_count{1, 0, moves, 0, 0, 1}));
+    }
+  } converting_key_checker;
+
+  struct counted_value_checker_type
+  {
+    using mapped_type = counted_value_type;
+    void operator()(emplace_kind kind, emplace_status status)
+    {
+      int copies = (kind == copy && status == success) ? 1 : 0;
+      int moves = (kind == move && status == success) ? 1 : 0;
+      BOOST_TEST_EQ(count_for<counted_value_type>(),
+        (smf_count{0, copies, moves, 0, 0, 0}));
+    }
+  } counted_value_checker;
+
+  struct converting_value_checker_type
+  {
+    using mapped_type = converting_value_type;
+    void operator()(emplace_kind, emplace_status status)
+    {
+      int ctors = (status == success) ? 1 : 0;
+      BOOST_TEST_EQ(
+        count_for<counted_value_type>(), (smf_count{ctors, 0, 0, 0, 0, 0}));
+    }
+  } converting_value_checker;
+
+  template <class X, class KC, class VC>
+  void emplace_map_key_value(
+    X*, emplace_kind kind, KC key_checker, VC value_checker)
+  {
+    using container = X;
+    using key_type = typename KC::key_type;
+    using mapped_type = typename VC::mapped_type;
+
+    container x;
+    key_type key{};
+    key_type key2 = key;
+    mapped_type value{};
+    mapped_type value2 = value;
+
+    {
+      reset_counts();
+      auto ret = (kind == copy) ? x.emplace(key, value)
+                                : x.emplace(std::move(key), std::move(value));
+      BOOST_TEST_EQ(ret, true);
+      key_checker(kind, success);
+      value_checker(kind, success);
+      BOOST_TEST_EQ(
+        count_for<converting_key_type>(), (smf_count{0, 0, 0, 0, 0, 0}));
+      BOOST_TEST_EQ(
+        count_for<converting_value_type>(), (smf_count{0, 0, 0, 0, 0, 0}));
+    }
+
+    {
+      reset_counts();
+      bool ret = x.emplace(key2, value2);
+      BOOST_TEST_EQ(ret, false);
+      key_checker(kind, fail);
+      value_checker(kind, fail);
+      BOOST_TEST_EQ(
+        count_for<converting_key_type>(), (smf_count{0, 0, 0, 0, 0, 0}));
+      BOOST_TEST_EQ(
+        count_for<converting_value_type>(), (smf_count{0, 0, 0, 0, 0, 0}));
+    }
+
+    {
+      reset_counts();
+      bool ret = x.emplace(std::move(key2), std::move(value2));
+      BOOST_TEST_EQ(ret, false);
+      key_checker(kind, fail);
+      value_checker(kind, fail);
+      BOOST_TEST_EQ(
+        count_for<converting_key_type>(), (smf_count{0, 0, 0, 0, 0, 0}));
+      BOOST_TEST_EQ(
+        count_for<converting_value_type>(), (smf_count{0, 0, 0, 0, 0, 0}));
+    }
+  }
+
+  boost::unordered::concurrent_flat_map<counted_key_type, counted_value_type>*
+    test_counted_flat_map = {};
+
+} // namespace
+
+// clang-format off
+
+UNORDERED_TEST(
+  emplace_map_key_value,
+  ((test_counted_flat_map))
+  ((copy)(move))
+  ((counted_key_checker)(converting_key_checker))
+  ((counted_value_checker)(converting_value_checker))
+)
+
+// clang-format on
+
 RUN_TESTS()

test/cfoa/exception_helpers.hpp

@@ -33,7 +33,7 @@ static std::size_t const num_threads =
 
 std::atomic_bool should_throw{false};
 
-constexpr std::uint32_t throw_threshold = 2500;
+constexpr std::uint32_t throw_threshold = 2300;
 constexpr std::uint32_t alloc_throw_threshold = 10;
 
 void enable_exceptions() { should_throw = true; }

test/cfoa/explicit_alloc_ctor_tests.cpp

@@ -0,0 +1,6 @@
+// Copyright 2024 Joaquin M Lopez Muoz.
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at htT://www.boost.org/LICENSE_1_0.txt)
+
+#define BOOST_UNORDERED_CFOA_TESTS
+#include "../unordered/explicit_alloc_ctor_tests.cpp"

test/cfoa/helpers.hpp

@@ -1,5 +1,6 @@
 // Copyright (C) 2023 Christian Mazakas
 // Copyright (C) 2023 Joaquin M Lopez Munoz
+// Copyright (C) 2024 Braden Ganetsky
 // 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)
 
@@ -207,7 +208,8 @@ template <class T> struct stateful_allocator2
   bool operator!=(stateful_allocator2 const& rhs) const { return x_ != rhs.x_; }
 };
 
-struct raii
+template <class Tag>
+struct basic_raii
 {
   static std::atomic<std::uint32_t> default_constructor;
   static std::atomic<std::uint32_t> copy_constructor;
@@ -219,17 +221,17 @@ struct raii
 
   int x_ = -1;
 
-  raii() { ++default_constructor; }
-  raii(int const x) : x_{x} { ++default_constructor; }
-  raii(raii const& rhs) : x_{rhs.x_} { ++copy_constructor; }
-  raii(raii&& rhs) noexcept : x_{rhs.x_}
+  basic_raii() { ++default_constructor; }
+  basic_raii(int const x) : x_{x} { ++default_constructor; }
+  basic_raii(basic_raii const& rhs) : x_{rhs.x_} { ++copy_constructor; }
+  basic_raii(basic_raii&& rhs) noexcept : x_{rhs.x_}
   {
     rhs.x_ = -1;
     ++move_constructor;
   }
-  ~raii() { ++destructor; }
+  ~basic_raii() { ++destructor; }
 
-  raii& operator=(raii const& rhs)
+  basic_raii& operator=(basic_raii const& rhs)
   {
     ++copy_assignment;
     if (this != &rhs) {
@@ -238,7 +240,7 @@ struct raii
     return *this;
   }
 
-  raii& operator=(raii&& rhs) noexcept
+  basic_raii& operator=(basic_raii&& rhs) noexcept
   {
     ++move_assignment;
     if (this != &rhs) {
@@ -248,37 +250,37 @@ struct raii
     return *this;
   }
 
-  friend bool operator==(raii const& lhs, raii const& rhs)
+  friend bool operator==(basic_raii const& lhs, basic_raii const& rhs)
   {
     return lhs.x_ == rhs.x_;
   }
 
-  friend bool operator!=(raii const& lhs, raii const& rhs)
+  friend bool operator!=(basic_raii const& lhs, basic_raii const& rhs)
   {
     return !(lhs == rhs);
   }
 
-  friend bool operator==(raii const& lhs, int const x) { return lhs.x_ == x; }
-  friend bool operator!=(raii const& lhs, int const x)
+  friend bool operator==(basic_raii const& lhs, int const x) { return lhs.x_ == x; }
+  friend bool operator!=(basic_raii const& lhs, int const x)
   {
     return !(lhs.x_ == x);
   }
 
-  friend bool operator==(int const x, raii const& rhs) { return rhs.x_ == x; }
+  friend bool operator==(int const x, basic_raii const& rhs) { return rhs.x_ == x; }
 
-  friend bool operator!=(int const x, raii const& rhs)
+  friend bool operator!=(int const x, basic_raii const& rhs)
   {
     return !(rhs.x_ == x);
   }
 
-  friend std::ostream& operator<<(std::ostream& os, raii const& rhs)
+  friend std::ostream& operator<<(std::ostream& os, basic_raii const& rhs)
   {
     os << "{ x_: " << rhs.x_ << " }";
     return os;
   }
 
   friend std::ostream& operator<<(
-    std::ostream& os, std::pair<raii const, raii> const& rhs)
+    std::ostream& os, std::pair<basic_raii const, basic_raii> const& rhs)
   {
     os << "pair<" << rhs.first << ", " << rhs.second << ">";
     return os;
@@ -294,16 +296,30 @@ struct raii
     move_assignment = 0;
   }
 
-  friend void swap(raii& lhs, raii& rhs) { std::swap(lhs.x_, rhs.x_); }
+  friend void swap(basic_raii& lhs, basic_raii& rhs) { std::swap(lhs.x_, rhs.x_); }
 };
 
-std::atomic<std::uint32_t> raii::default_constructor{0};
-std::atomic<std::uint32_t> raii::copy_constructor{0};
-std::atomic<std::uint32_t> raii::move_constructor{0};
-std::atomic<std::uint32_t> raii::destructor{0};
-std::atomic<std::uint32_t> raii::copy_assignment{0};
-std::atomic<std::uint32_t> raii::move_assignment{0};
+template <class Tag> std::atomic<std::uint32_t> basic_raii<Tag>::default_constructor(0);
+template <class Tag> std::atomic<std::uint32_t> basic_raii<Tag>::copy_constructor(0);
+template <class Tag> std::atomic<std::uint32_t> basic_raii<Tag>::move_constructor(0);
+template <class Tag> std::atomic<std::uint32_t> basic_raii<Tag>::destructor(0);
+template <class Tag> std::atomic<std::uint32_t> basic_raii<Tag>::copy_assignment(0);
+template <class Tag> std::atomic<std::uint32_t> basic_raii<Tag>::move_assignment(0);
 
+struct raii_tag_
+{
+};
+class raii : public basic_raii<raii_tag_>
+{
+  using basic_raii::basic_raii;
+};
+
+template <class Tag>
+std::size_t hash_value(basic_raii<Tag> const& r) noexcept
+{
+  boost::hash<int> hasher;
+  return hasher(r.x_);
+}
 std::size_t hash_value(raii const& r) noexcept
 {
   boost::hash<int> hasher;
@@ -311,6 +327,13 @@ std::size_t hash_value(raii const& r) noexcept
 }
 
 namespace std {
+  template <class Tag> struct hash<basic_raii<Tag>>
+  {
+    std::size_t operator()(basic_raii<Tag> const& r) const noexcept
+    {
+      return hash_value(r);
+    }
+  };
   template <> struct hash<raii>
   {
     std::size_t operator()(raii const& r) const noexcept

test/cfoa/insert_tests.cpp

@@ -156,6 +156,9 @@ namespace {
     BOOST_WORKAROUND(BOOST_GCC_VERSION, <  50500)
       // some versions of old gcc have trouble eliding copies here
       // https://godbolt.org/z/Ebo6TbvaG
+#elif BOOST_WORKAROUND(BOOST_GCC_VERSION, >= 40900) && \
+      BOOST_WORKAROUND(BOOST_GCC_VERSION, <  50000)
+      // seemingly same problem, though the snippet above does not reveal it
 #else
       BOOST_TEST_EQ(raii::copy_constructor, 0u);
 #endif
@@ -488,8 +491,10 @@ namespace {
 
       BOOST_TEST_EQ(
         raii::default_constructor, value_type_cardinality * values2.size());
-#if BOOST_WORKAROUND(BOOST_GCC_VERSION, >= 50300) && \
-    BOOST_WORKAROUND(BOOST_GCC_VERSION, <  50500)
+#if (BOOST_WORKAROUND(BOOST_GCC_VERSION, >= 50300) && \
+     BOOST_WORKAROUND(BOOST_GCC_VERSION, <  50500)) || \
+    (BOOST_WORKAROUND(BOOST_GCC_VERSION, >= 40900) && \
+     BOOST_WORKAROUND(BOOST_GCC_VERSION, <  50000))
       // skip test
 #else
       BOOST_TEST_EQ(raii::copy_constructor, 0u);
@@ -525,8 +530,10 @@ namespace {
 
       BOOST_TEST_EQ(
         raii::default_constructor, value_type_cardinality * values2.size());
-#if BOOST_WORKAROUND(BOOST_GCC_VERSION, >= 50300) && \
-    BOOST_WORKAROUND(BOOST_GCC_VERSION, <  50500)
+#if (BOOST_WORKAROUND(BOOST_GCC_VERSION, >= 50300) && \
+     BOOST_WORKAROUND(BOOST_GCC_VERSION, <  50500)) || \
+    (BOOST_WORKAROUND(BOOST_GCC_VERSION, >= 40900) && \
+     BOOST_WORKAROUND(BOOST_GCC_VERSION, <  50000))
       // skip test
 #else
       BOOST_TEST_EQ(raii::copy_constructor, 0u);

test/helpers/count.hpp

@@ -1,5 +1,6 @@
 
 // Copyright 2008-2009 Daniel James.
+// Copyright 2024 Braden Ganetsky.
 // Distributed under the Boost Software License, Version 1.0. (See accompanying
 // file LICENSE_1_0.txt or move at http://www.boost.org/LICENSE_1_0.txt)
 
@@ -7,6 +8,7 @@
 #define BOOST_UNORDERED_TEST_HELPERS_COUNT_HEAD
 
 #include <boost/core/lightweight_test.hpp>
+#include <boost/container_hash/hash.hpp>
 
 namespace test {
   struct object_count
@@ -84,6 +86,114 @@ namespace test {
       return global_object_count.constructions - constructions_;
     }
   };
-}
+
+  struct smf_count
+  {
+    int default_constructions = 0;
+    int copy_constructions = 0;
+    int move_constructions = 0;
+    int copy_assignments = 0;
+    int move_assignments = 0;
+    int destructions = 0;
+
+#if (BOOST_CXX_VERSION < 201402L) || (defined(_MSC_VER) && _MSC_VER < 1910)
+    smf_count() = default;
+
+    smf_count(int default_constructions_, int copy_constructions_,
+      int move_constructions_, int copy_assignments_, int move_assignments_,
+      int destructions_)
+        : default_constructions(default_constructions_),
+          copy_constructions(copy_constructions_),
+          move_constructions(move_constructions_),
+          copy_assignments(copy_assignments_),
+          move_assignments(move_assignments_), destructions(destructions_)
+    {
+    }
+#endif
+
+    void reset() { *this = smf_count(); }
+
+    void default_construct() { ++default_constructions; }
+    void copy_construct() { ++copy_constructions; }
+    void move_construct() { ++move_constructions; }
+    void copy_assign() { ++copy_assignments; }
+    void move_assign() { ++move_assignments; }
+    void destruct() { ++destructions; }
+
+    friend bool operator==(smf_count const& lhs, smf_count const& rhs)
+    {
+      return lhs.default_constructions == rhs.default_constructions &&
+             lhs.copy_constructions == rhs.copy_constructions &&
+             lhs.move_constructions == rhs.move_constructions &&
+             lhs.copy_assignments == rhs.copy_assignments &&
+             lhs.move_assignments == rhs.move_assignments &&
+             lhs.destructions == rhs.destructions;
+    }
+
+    friend std::ostream& operator<<(std::ostream& out, smf_count const& c)
+    {
+      out << "[default_constructions: " << c.default_constructions
+          << ", copy_constructions: " << c.copy_constructions
+          << ", move_constructions: " << c.move_constructions
+          << ", copy_assignments: " << c.copy_assignments
+          << ", move_assignments: " << c.move_assignments
+          << ", destructions: " << c.destructions << "]";
+      return out;
+    }
+  };
+
+  template <class Tag> class smf_counted_object
+  {
+  public:
+    static smf_count count;
+    static void reset_count() { count.reset(); }
+
+    smf_counted_object(int index) : smf_counted_object() { index_ = index; }
+
+    smf_counted_object() : index_(++running_index)
+    {
+      count.default_construct();
+    }
+    smf_counted_object(smf_counted_object const& rhs) : index_(rhs.index_)
+    {
+      count.copy_construct();
+    }
+    smf_counted_object(smf_counted_object&& rhs) noexcept : index_(rhs.index_)
+    {
+      count.move_construct();
+    }
+    smf_counted_object& operator=(smf_counted_object const& rhs)
+    {
+      count.copy_assign();
+      index_ = rhs.index_;
+      return *this;
+    }
+    smf_counted_object& operator=(smf_counted_object&& rhs) noexcept
+    {
+      count.move_assign();
+      index_ = rhs.index_;
+      return *this;
+    }
+    ~smf_counted_object() { count.destruct(); }
+
+    friend bool operator==(
+      smf_counted_object const& lhs, smf_counted_object const& rhs)
+    {
+      return lhs.index_ == rhs.index_;
+    }
+
+    friend std::size_t hash_value(smf_counted_object const& x)
+    {
+      return boost::hash<int>()(x.index_);
+    }
+
+    int index_;
+
+  private:
+    static int running_index;
+  };
+  template <class Tag> smf_count smf_counted_object<Tag>::count = {};
+  template <class Tag> int smf_counted_object<Tag>::running_index = 0;
+} // namespace test
 
 #endif

test/helpers/unordered.hpp

@@ -21,4 +21,10 @@
 #include "postfix.hpp"
 // clang-format on
 
+#if defined(BOOST_LIBSTDCXX_VERSION)
+#if BOOST_LIBSTDCXX_VERSION < 60000
+#define BOOST_UNORDERED_NO_INIT_TYPE_TESTS
+#endif
+#endif
+
 #endif

test/unordered/emplace_smf_tests.cpp

@@ -0,0 +1,377 @@
+//
+// Copyright 2023-2024 Braden Ganetsky.
+// 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)
+
+#include "../helpers/unordered.hpp"
+
+#include "../helpers/count.hpp"
+#include "../helpers/test.hpp"
+
+namespace emplace_smf_tests {
+  using test::smf_count;
+  using test::smf_counted_object;
+
+  using converting_key = smf_counted_object<struct cvt_key_tag_>;
+  using converting_value = smf_counted_object<struct cvt_value_tag_>;
+
+  class counted_key : public smf_counted_object<struct key_tag_>
+  {
+  public:
+    using smf_counted_object::smf_counted_object;
+    counted_key() = default;
+    counted_key(const converting_key& k) : counted_key(k.index_) {}
+  };
+  class counted_value : public smf_counted_object<struct value_tag_>
+  {
+  public:
+    using smf_counted_object::smf_counted_object;
+    counted_value() = default;
+    counted_value(const converting_value& v) : counted_value(v.index_) {}
+  };
+
+  class immovable_key : public smf_counted_object<struct imm_key_tag_>
+  {
+  public:
+    using smf_counted_object::smf_counted_object;
+    immovable_key(immovable_key&&) = delete;
+    immovable_key& operator=(immovable_key&&) = delete;
+  };
+  class immovable_value : public smf_counted_object<struct imm_value_tag_>
+  {
+  public:
+    using smf_counted_object::smf_counted_object;
+    immovable_value(immovable_value&&) = delete;
+    immovable_value& operator=(immovable_value&&) = delete;
+  };
+
+  void reset_counts()
+  {
+    counted_key::reset_count();
+    counted_value::reset_count();
+    converting_key::reset_count();
+    converting_value::reset_count();
+    immovable_key::reset_count();
+    immovable_value::reset_count();
+  }
+
+#ifdef BOOST_UNORDERED_FOA_TESTS
+  static boost::unordered_flat_map<counted_key, counted_value>* test_smf_map;
+  static boost::unordered_node_map<counted_key, counted_value>*
+    test_smf_node_map;
+  static boost::unordered_flat_set<counted_value>* test_smf_set;
+  static boost::unordered_node_set<counted_value>* test_smf_node_set;
+#define EMPLACE_SMF_TESTS_MAP_ARGS ((test_smf_map)(test_smf_node_map))
+#define EMPLACE_SMF_TESTS_SET_ARGS ((test_smf_set)(test_smf_node_set))
+#else
+  static boost::unordered_map<counted_key, counted_value>* test_smf_map;
+  static boost::unordered_set<counted_value>* test_smf_set;
+#define EMPLACE_SMF_TESTS_MAP_ARGS ((test_smf_map))
+#define EMPLACE_SMF_TESTS_SET_ARGS ((test_smf_set))
+#endif
+
+  template <class X> static void emplace_smf_value_type_map(X*)
+  {
+    using container = X;
+    using value_type = typename container::value_type;
+
+    container x;
+
+    {
+      value_type val{counted_key{}, counted_value{}};
+      x.clear();
+      reset_counts();
+      x.emplace(val);
+      BOOST_TEST_EQ(counted_key::count, (smf_count{0, 1, 0, 0, 0, 0}));
+      BOOST_TEST_EQ(counted_value::count, (smf_count{0, 1, 0, 0, 0, 0}));
+    }
+
+    {
+      value_type val{counted_key{}, counted_value{}};
+      x.clear();
+      reset_counts();
+      x.emplace(std::move(val));
+      BOOST_TEST_EQ(counted_key::count, (smf_count{0, 1, 0, 0, 0, 0}));
+      BOOST_TEST_EQ(counted_value::count, (smf_count{0, 0, 1, 0, 0, 0}));
+    }
+
+    {
+      x.clear();
+      reset_counts();
+      x.emplace(value_type{counted_key{}, counted_value{}});
+      BOOST_TEST_EQ(counted_key::count, (smf_count{1, 1, 1, 0, 0, 2}));
+      BOOST_TEST_EQ(counted_value::count, (smf_count{1, 0, 2, 0, 0, 2}));
+    }
+
+    {
+      counted_key key{};
+      counted_value value{};
+      x.clear();
+      reset_counts();
+      x.emplace(value_type{std::move(key), std::move(value)});
+      BOOST_TEST_EQ(counted_key::count, (smf_count{0, 1, 1, 0, 0, 1}));
+      BOOST_TEST_EQ(counted_value::count, (smf_count{0, 0, 2, 0, 0, 1}));
+    }
+  }
+
+  UNORDERED_TEST(emplace_smf_value_type_map, EMPLACE_SMF_TESTS_MAP_ARGS)
+
+  template <class X> static void emplace_smf_init_type_map(X*)
+  {
+    using container = X;
+#ifdef BOOST_UNORDERED_FOA_TESTS
+    using init_type = typename container::init_type;
+#else
+    using raw_key =
+      typename std::remove_const<typename container::key_type>::type;
+    using init_type = std::pair<raw_key, typename container::mapped_type>;
+#endif
+
+    container x;
+
+    {
+      init_type val{counted_key{}, counted_value{}};
+      x.clear();
+      reset_counts();
+      x.emplace(val);
+      BOOST_TEST_EQ(counted_key::count, (smf_count{0, 1, 0, 0, 0, 0}));
+      BOOST_TEST_EQ(counted_value::count, (smf_count{0, 1, 0, 0, 0, 0}));
+    }
+
+    {
+      init_type val{counted_key{}, counted_value{}};
+      x.clear();
+      reset_counts();
+      x.emplace(std::move(val));
+      BOOST_TEST_EQ(counted_key::count, (smf_count{0, 0, 1, 0, 0, 0}));
+      BOOST_TEST_EQ(counted_value::count, (smf_count{0, 0, 1, 0, 0, 0}));
+    }
+
+    {
+      x.clear();
+      reset_counts();
+      x.emplace(init_type{counted_key{}, counted_value{}});
+      BOOST_TEST_EQ(counted_key::count, (smf_count{1, 0, 2, 0, 0, 2}));
+      BOOST_TEST_EQ(counted_value::count, (smf_count{1, 0, 2, 0, 0, 2}));
+    }
+
+    {
+      counted_key key{};
+      counted_value value{};
+      x.clear();
+      reset_counts();
+      x.emplace(init_type{std::move(key), std::move(value)});
+      BOOST_TEST_EQ(counted_key::count, (smf_count{0, 0, 2, 0, 0, 1}));
+      BOOST_TEST_EQ(counted_value::count, (smf_count{0, 0, 2, 0, 0, 1}));
+    }
+  }
+
+  UNORDERED_TEST(emplace_smf_init_type_map, EMPLACE_SMF_TESTS_MAP_ARGS)
+
+  template <class X> static void emplace_smf_value_type_set(X*)
+  {
+    using container = X;
+    using value_type = typename container::value_type;
+#ifdef BOOST_UNORDERED_FOA_TESTS
+    BOOST_STATIC_ASSERT(
+      std::is_same<value_type, typename container::init_type>::value);
+#endif
+    BOOST_STATIC_ASSERT(std::is_same<value_type, counted_value>::value);
+
+    container x;
+
+    {
+      counted_value val{};
+      x.clear();
+      reset_counts();
+      x.emplace(val);
+      BOOST_TEST_EQ(counted_value::count, (smf_count{0, 1, 0, 0, 0, 0}));
+    }
+
+    {
+      counted_value val{};
+      x.clear();
+      reset_counts();
+      x.emplace(std::move(val));
+      BOOST_TEST_EQ(counted_value::count, (smf_count{0, 0, 1, 0, 0, 0}));
+    }
+
+    {
+      x.clear();
+      reset_counts();
+      x.emplace(counted_value{});
+      BOOST_TEST_EQ(counted_value::count, (smf_count{1, 0, 1, 0, 0, 1}));
+    }
+  }
+
+  UNORDERED_TEST(emplace_smf_value_type_set, EMPLACE_SMF_TESTS_SET_ARGS)
+
+  enum emplace_kind
+  {
+    copy,
+    move
+  };
+
+  enum emplace_status
+  {
+    fail,
+    success
+  };
+
+  struct counted_key_checker_type
+  {
+    using key_type = counted_key;
+    void operator()(emplace_kind kind, emplace_status status)
+    {
+      int copies = (kind == copy && status == success) ? 1 : 0;
+      int moves = (kind == move && status == success) ? 1 : 0;
+      BOOST_TEST_EQ(counted_key::count, (smf_count{0, copies, moves, 0, 0, 0}));
+    }
+  } counted_key_checker;
+
+  struct converting_key_checker_type
+  {
+    using key_type = converting_key;
+    void operator()(emplace_kind, emplace_status status)
+    {
+      int moves = (status == success) ? 1 : 0;
+      BOOST_TEST_EQ(counted_key::count, (smf_count{1, 0, moves, 0, 0, 1}));
+    }
+  } converting_key_checker;
+
+  struct counted_value_checker_type
+  {
+    using mapped_type = counted_value;
+    void operator()(emplace_kind kind, emplace_status status)
+    {
+      int copies = (kind == copy && status == success) ? 1 : 0;
+      int moves = (kind == move && status == success) ? 1 : 0;
+      BOOST_TEST_EQ(
+        counted_value::count, (smf_count{0, copies, moves, 0, 0, 0}));
+    }
+  } counted_value_checker;
+
+  struct converting_value_checker_type
+  {
+    using mapped_type = converting_value;
+    void operator()(emplace_kind, emplace_status status)
+    {
+      int ctors = (status == success) ? 1 : 0;
+      BOOST_TEST_EQ(counted_value::count, (smf_count{ctors, 0, 0, 0, 0, 0}));
+    }
+  } converting_value_checker;
+
+  template <class X, class KC, class VC>
+  static void emplace_smf_key_value_map(
+    X*, emplace_kind kind, KC key_checker, VC value_checker)
+  {
+    using container = X;
+    using key_type = typename KC::key_type;
+    using mapped_type = typename VC::mapped_type;
+
+    container x;
+    key_type key{};
+    key_type key2 = key;
+    mapped_type value{};
+    mapped_type value2 = value;
+
+    {
+      reset_counts();
+      auto ret = (kind == copy) ? x.emplace(key, value)
+                                : x.emplace(std::move(key), std::move(value));
+      BOOST_TEST_EQ(ret.second, true);
+      key_checker(kind, success);
+      value_checker(kind, success);
+      BOOST_TEST_EQ(converting_key::count, (smf_count{0, 0, 0, 0, 0, 0}));
+      BOOST_TEST_EQ(converting_value::count, (smf_count{0, 0, 0, 0, 0, 0}));
+    }
+
+    {
+      reset_counts();
+      auto ret = x.emplace(key2, value2);
+      BOOST_TEST_EQ(ret.second, false);
+      key_checker(kind, fail);
+      value_checker(kind, fail);
+      BOOST_TEST_EQ(converting_key::count, (smf_count{0, 0, 0, 0, 0, 0}));
+      BOOST_TEST_EQ(converting_value::count, (smf_count{0, 0, 0, 0, 0, 0}));
+    }
+
+    {
+      reset_counts();
+      auto ret = x.emplace(std::move(key2), std::move(value2));
+      BOOST_TEST_EQ(ret.second, false);
+      key_checker(kind, fail);
+      value_checker(kind, fail);
+      BOOST_TEST_EQ(converting_key::count, (smf_count{0, 0, 0, 0, 0, 0}));
+      BOOST_TEST_EQ(converting_value::count, (smf_count{0, 0, 0, 0, 0, 0}));
+    }
+  }
+
+  // clang-format off
+
+  UNORDERED_TEST(
+    emplace_smf_key_value_map,
+    EMPLACE_SMF_TESTS_MAP_ARGS
+    ((copy)(move))
+    ((counted_key_checker)(converting_key_checker))
+    ((counted_value_checker)(converting_value_checker))
+  )
+
+  // clang-format on
+
+  template <class X> static void emplace_smf_key_value_map_immovable_key(X*)
+  {
+#ifndef BOOST_UNORDERED_NO_INIT_TYPE_TESTS
+    using container = X;
+    BOOST_STATIC_ASSERT(
+      std::is_same<immovable_key, typename X::key_type>::value);
+    using mapped_type = typename X::mapped_type;
+
+    container x;
+
+    {
+      reset_counts();
+      auto ret = x.emplace(0, 0);
+      BOOST_TEST_EQ(ret.second, true);
+      BOOST_TEST_EQ(immovable_key::count, (smf_count{1, 0, 0, 0, 0, 0}));
+      BOOST_TEST_EQ(mapped_type::count, (smf_count{1, 0, 0, 0, 0, 0}));
+    }
+
+    {
+      reset_counts();
+      auto ret = x.emplace(0, 1);
+      BOOST_TEST_EQ(ret.second, false);
+      BOOST_TEST_EQ(immovable_key::count, (smf_count{1, 0, 0, 0, 0, 1}));
+      BOOST_TEST_EQ(mapped_type::count, (smf_count{1, 0, 0, 0, 0, 1}));
+    }
+#endif
+  }
+
+#ifdef BOOST_UNORDERED_FOA_TESTS
+  static boost::unordered_node_map<immovable_key, counted_value>*
+    test_smf_node_map_immovable_key_counted_value;
+  static boost::unordered_node_map<immovable_key, immovable_value>*
+    test_smf_node_map_immovable_key_immovable_value;
+#define EMPLACE_SMF_TESTS_MAP_IMMOVABLE_ARGS                                   \
+  ((test_smf_node_map_immovable_key_counted_value)(test_smf_node_map_immovable_key_immovable_value))
+#else
+  static boost::unordered_map<immovable_key, counted_value>*
+    test_smf_map_immovable_key_counted_value;
+  static boost::unordered_map<immovable_key, immovable_value>*
+    test_smf_map_immovable_key_immovable_value;
+#define EMPLACE_SMF_TESTS_MAP_IMMOVABLE_ARGS                                   \
+  ((test_smf_map_immovable_key_counted_value)(test_smf_map_immovable_key_immovable_value))
+#endif
+
+  // clang-format off
+
+  UNORDERED_TEST(
+    emplace_smf_key_value_map_immovable_key,
+    EMPLACE_SMF_TESTS_MAP_IMMOVABLE_ARGS
+  )
+
+  // clang-format on
+
+} // namespace emplace_smf_tests
+
+RUN_TESTS()

test/unordered/explicit_alloc_ctor_tests.cpp

@@ -0,0 +1,152 @@
+// Copyright 2024 Joaquin M Lopez Muoz.
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at htT://www.boost.org/LICENSE_1_0.txt)
+
+#ifdef BOOST_UNORDERED_CFOA_TESTS
+#include <boost/unordered/concurrent_flat_map.hpp>
+#include <boost/unordered/concurrent_flat_set.hpp>
+#else
+#include "../helpers/unordered.hpp"
+#endif
+
+#include "../helpers/test.hpp"
+#include <boost/type_traits/make_void.hpp>
+#include <memory>
+#include <vector>
+
+template <class T> struct explicit_allocator
+{
+  typedef T value_type;
+
+  explicit_allocator() {}
+
+  template <class U> 
+  explicit explicit_allocator(const explicit_allocator<U>&) {}
+
+  template<class U>
+  bool operator==(explicit_allocator<U> const &) const noexcept
+  {
+    return true;
+  }
+
+  template<class U>
+  bool operator!=(explicit_allocator<U> const &) const noexcept
+  {
+    return false;
+  }
+    
+  T* allocate(std::size_t n)
+  {
+    return std::allocator<T>().allocate(n); 
+  }
+
+  void deallocate(T* p, std::size_t n)
+  {
+    std::allocator<T>().deallocate(p, n); 
+  }
+};
+
+template<typename Container,typename = void> struct has_extract:
+std::false_type {};
+
+template<typename Container>
+struct has_extract<
+  Container, boost::void_t<typename Container::insert_return_type>
+>: std::true_type {};
+
+template <class Container> void test_explicit_alloc_ctor_extract(
+  Container&, std::false_type)
+{
+}
+
+template <class Container> void test_explicit_alloc_ctor_extract(
+  Container& c, std::true_type)
+{
+  auto n = c.extract(c.begin());
+  c.insert(std::move(n));
+  n = c.extract(typename Container::key_type());
+  c.insert(std::move(n));
+}
+
+template <class Container> void test_explicit_alloc_ctor_extract(Container& c)
+{
+  test_explicit_alloc_ctor_extract(c, has_extract<Container>());
+}
+
+template <class Container> void test_explicit_alloc_ctor()
+{
+  using key_type = typename Container::key_type;
+  using value_type = typename Container::value_type;
+  using hasher = typename Container::hasher;
+  using allocator_type = typename Container::allocator_type;
+
+  allocator_type                    al;
+  std::initializer_list<value_type> il{};
+  hasher                            h;
+  std::vector<value_type>           v;
+  Container                         c,
+                                    c2(0),
+                                    c3(v.begin(), v.end()),
+                                    c4(c3),
+                                    c5(std::move(c4)),
+                                    c6(v.begin(), v.end(), al),
+                                    c7(al),
+                                    c8(c7, al),
+                                    c9(std::move(c8), al),
+                                    c10(il),
+                                    c11(0, al),
+                                    c12(0, h, al),
+                                    c13(v.begin(), v.end(), 0, al),
+                                    c14(v.begin(), v.end(), 0, h, al),
+                                    c15(il, al),
+                                    c16(il, 0, al),
+                                    c17(il, 0, h, al);
+  value_type                        x{};
+  key_type                          k{};
+
+  c = c2;
+  c = std::move(c2);
+  c = il;
+  c.swap(c3);
+  c.insert(x);
+#ifdef BOOST_UNORDERED_CFOA_TESTS
+  (void) c.visit(k, [](const value_type&) {});
+#else
+  (void) c.find(k);
+#endif
+  test_explicit_alloc_ctor_extract(c);
+}
+
+UNORDERED_AUTO_TEST (explicit_alloc_ctor) {
+#if defined(BOOST_UNORDERED_CFOA_TESTS)
+  test_explicit_alloc_ctor<boost::concurrent_flat_map<int, int,
+    boost::hash<int>, std::equal_to<int>,
+    explicit_allocator<std::pair<const int, int> > > >();
+  test_explicit_alloc_ctor<boost::concurrent_flat_set<
+    int, boost::hash<int>, std::equal_to<int>, explicit_allocator<int> > >();
+#elif defined(BOOST_UNORDERED_FOA_TESTS)
+  test_explicit_alloc_ctor<boost::unordered_flat_map<int, int,
+    boost::hash<int>, std::equal_to<int>,
+    explicit_allocator<std::pair<const int, int> > > >();
+  test_explicit_alloc_ctor<boost::unordered_flat_set<
+    int, boost::hash<int>, std::equal_to<int>, explicit_allocator<int> > >();
+  test_explicit_alloc_ctor<boost::unordered_node_map<int, int,
+    boost::hash<int>, std::equal_to<int>,
+    explicit_allocator<std::pair<const int, int> > > >();
+  test_explicit_alloc_ctor<boost::unordered_node_set<
+    int, boost::hash<int>, std::equal_to<int>, explicit_allocator<int> > >();
+#else
+  test_explicit_alloc_ctor<boost::unordered_map<int, int,
+    boost::hash<int>, std::equal_to<int>,
+    explicit_allocator<std::pair<const int, int> > > >();
+  test_explicit_alloc_ctor<boost::unordered_multimap<int, int,
+    boost::hash<int>, std::equal_to<int>,
+    explicit_allocator<std::pair<const int, int> > > >();
+  test_explicit_alloc_ctor<boost::unordered_set<
+    int, boost::hash<int>, std::equal_to<int>, explicit_allocator<int> > >();
+  test_explicit_alloc_ctor<boost::unordered_multiset<
+    int, boost::hash<int>, std::equal_to<int>, explicit_allocator<int> > >();
+#endif
+}
+
+RUN_TESTS()

test/unordered/find_tests.cpp

@@ -1,6 +1,7 @@
 
 // Copyright 2006-2009 Daniel James.
 // Copyright (C) 2022-2023 Christian Mazakas
+// Copyright (C) 2024 Joaquin M Lopez Munoz.
 // 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)
 
@@ -112,6 +113,7 @@ namespace find_tests {
     typedef typename test::random_values<X>::iterator value_iterator;
     test::random_values<X> v(500, generator);
     X x(v.begin(), v.end());
+    X const& x_const = x;
 
     compatible_hash h;
     compatible_predicate eq;
@@ -119,6 +121,7 @@ namespace find_tests {
     for (value_iterator it = v.begin(), end = v.end(); it != end; ++it) {
       typename X::key_type key = test::get_key<X>(*it);
       BOOST_TEST(x.find(key) == x.find(compatible_key(key), h, eq));
+      BOOST_TEST(x_const.find(key) == x_const.find(compatible_key(key), h, eq));
     }
 
     test::random_values<X> v2(20, generator);
@@ -126,6 +129,7 @@ namespace find_tests {
     for (value_iterator it = v2.begin(), end = v2.end(); it != end; ++it) {
       typename X::key_type key = test::get_key<X>(*it);
       BOOST_TEST(x.find(key) == x.find(compatible_key(key), h, eq));
+      BOOST_TEST(x_const.find(key) == x_const.find(compatible_key(key), h, eq));
     }
   }
 

test/unordered/init_type_insert_tests.cpp

@@ -12,12 +12,6 @@
 
 #include <boost/config.hpp>
 
-#if defined(BOOST_LIBSTDCXX_VERSION)
-#if BOOST_LIBSTDCXX_VERSION < 60000
-#define BOOST_UNORDERED_NO_INIT_TYPE_TESTS
-#endif
-#endif
-
 struct move_only
 {
   int x_ = -1;