From f6a077e102ed6704422481fcc49ff73875d54ed9 Mon Sep 17 00:00:00 2001
From: Christian Mazakas <christian.mazakas@gmail.com>
Date: Tue, 4 Jan 2022 11:37:39 -0800
Subject: [PATCH 1/2] Add transparent test support for multiset's `extract()`

---
 test/unordered/transparent_tests.cpp | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/test/unordered/transparent_tests.cpp b/test/unordered/transparent_tests.cpp
index 9f7a129c..59fb48d7 100644
--- a/test/unordered/transparent_tests.cpp
+++ b/test/unordered/transparent_tests.cpp
@@ -1461,6 +1461,26 @@ transparent_unordered_set::node_type set_extract_const_overload_compile_test()
   return set.extract(c);
 }
 
+transparent_unordered_multiset::node_type
+multiset_extract_overload_compile_test()
+{
+  convertible_to_iterator<transparent_unordered_multiset> c;
+  transparent_unordered_multiset set;
+  transparent_unordered_multiset::iterator pos = set.begin();
+  pos = c;
+  return set.extract(c);
+}
+
+transparent_unordered_multiset::node_type
+multiset_extract_const_overload_compile_test()
+{
+  convertible_to_const_iterator<transparent_unordered_multiset> c;
+  transparent_unordered_multiset set;
+  transparent_unordered_multiset::const_iterator pos = set.begin();
+  pos = c;
+  return set.extract(c);
+}
+
 template <class UnorderedSet> void test_set_transparent_extract()
 {
   typedef typename UnorderedSet::node_type node_type;
@@ -1735,6 +1755,7 @@ void test_unordered_multiset()
     test_set_transparent_find<unordered_set>();
     test_set_transparent_erase<unordered_set>();
     test_set_transparent_equal_range<unordered_set>();
+    test_set_transparent_extract<unordered_set>();
   }
 
   {
@@ -1746,6 +1767,7 @@ void test_unordered_multiset()
     test_set_non_transparent_find<unordered_set>();
     test_set_non_transparent_erase<unordered_set>();
     test_set_non_transparent_equal_range<unordered_set>();
+    test_set_non_transparent_extract<unordered_set>();
   }
 
   {
@@ -1758,6 +1780,7 @@ void test_unordered_multiset()
     test_set_non_transparent_find<unordered_set>();
     test_set_non_transparent_erase<unordered_set>();
     test_set_non_transparent_equal_range<unordered_set>();
+    test_set_non_transparent_extract<unordered_set>();
   }
 
   {
@@ -1770,6 +1793,7 @@ void test_unordered_multiset()
     test_set_non_transparent_find<unordered_set>();
     test_set_non_transparent_erase<unordered_set>();
     test_set_non_transparent_equal_range<unordered_set>();
+    test_set_non_transparent_extract<unordered_set>();
   }
 }
 

From 1c459e6ee611e72ef8cd703dc65af7007ca9f87f Mon Sep 17 00:00:00 2001
From: Christian Mazakas <christian.mazakas@gmail.com>
Date: Tue, 4 Jan 2022 11:37:51 -0800
Subject: [PATCH 2/2] Implement heterogeneous `extract()` for multiset

---
 include/boost/unordered/unordered_set.hpp | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/include/boost/unordered/unordered_set.hpp b/include/boost/unordered/unordered_set.hpp
index bd191e30..c66fef7e 100644
--- a/include/boost/unordered/unordered_set.hpp
+++ b/include/boost/unordered/unordered_set.hpp
@@ -1015,6 +1015,15 @@ namespace boost {
         return node_type(table_.extract_by_key(k), table_.node_alloc());
       }
 
+      template <class Key>
+      typename boost::enable_if_c<
+        detail::transparent_non_iterable<Key, unordered_multiset>::value,
+        node_type>::type
+      extract(const Key& k)
+      {
+        return node_type(table_.extract_by_key_impl(k), table_.node_alloc());
+      }
+
       iterator insert(BOOST_RV_REF(node_type) np)
       {
         return table_.move_insert_node_type_equiv(np);