From c485bc975a010baf433cd208546341fc875c82e1 Mon Sep 17 00:00:00 2001
From: Christian Mazakas <christian.mazakas@gmail.com>
Date: Mon, 3 Jan 2022 14:43:37 -0800
Subject: [PATCH 1/2] Add transparent test support for multiset's `count()`

---
 test/unordered/transparent_tests.cpp | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/test/unordered/transparent_tests.cpp b/test/unordered/transparent_tests.cpp
index e0a1111c..7d8f93d7 100644
--- a/test/unordered/transparent_tests.cpp
+++ b/test/unordered/transparent_tests.cpp
@@ -1605,6 +1605,7 @@ void test_unordered_multiset()
       transparent_key_equal>
       unordered_set;
 
+    test_set_transparent_count<unordered_set>();
     test_set_transparent_find<unordered_set>();
     test_set_transparent_erase<unordered_set>();
     test_set_transparent_equal_range<unordered_set>();
@@ -1615,6 +1616,7 @@ void test_unordered_multiset()
     //
     typedef boost::unordered_multiset<key, hasher, key_equal> unordered_set;
 
+    test_set_non_transparent_count<unordered_set>();
     test_set_non_transparent_find<unordered_set>();
     test_set_non_transparent_erase<unordered_set>();
     test_set_non_transparent_equal_range<unordered_set>();
@@ -1626,6 +1628,7 @@ void test_unordered_multiset()
     typedef boost::unordered_multiset<key, transparent_hasher, key_equal>
       unordered_set;
 
+    test_set_non_transparent_count<unordered_set>();
     test_set_non_transparent_find<unordered_set>();
     test_set_non_transparent_erase<unordered_set>();
     test_set_non_transparent_equal_range<unordered_set>();
@@ -1637,6 +1640,7 @@ void test_unordered_multiset()
     typedef boost::unordered_multiset<key, hasher, transparent_key_equal>
       unordered_set;
 
+    test_set_non_transparent_count<unordered_set>();
     test_set_non_transparent_find<unordered_set>();
     test_set_non_transparent_erase<unordered_set>();
     test_set_non_transparent_equal_range<unordered_set>();

From d5e5c08b875e1d4ef2e0bd1354ebfd8e218fd2d7 Mon Sep 17 00:00:00 2001
From: Christian Mazakas <christian.mazakas@gmail.com>
Date: Mon, 3 Jan 2022 14:43:51 -0800
Subject: [PATCH 2/2] Implement heterogeneous `count()` for multiset

---
 include/boost/unordered/unordered_set.hpp | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/include/boost/unordered/unordered_set.hpp b/include/boost/unordered/unordered_set.hpp
index 81f6e2f4..92ab11c5 100644
--- a/include/boost/unordered/unordered_set.hpp
+++ b/include/boost/unordered/unordered_set.hpp
@@ -1092,6 +1092,18 @@ namespace boost {
 
       size_type count(const key_type&) const;
 
+      template <class Key>
+      typename boost::enable_if_c<detail::are_transparent<Key, H, P>::value,
+        size_type>::type
+      count(const Key& k) const
+      {
+        node_pointer n = table_.find_node_impl(
+          table::policy::apply_hash(this->hash_function(), k), k,
+          this->key_eq());
+
+        return n ? table_.group_count(n) : 0;
+      }
+
       std::pair<const_iterator, const_iterator> equal_range(
         const key_type&) const;