From ad8a11bb4928c867df13b844f2495a63bfa16884 Mon Sep 17 00:00:00 2001
From: Christian Mazakas <christian.mazakas@gmail.com>
Date: Wed, 12 Jan 2022 11:31:54 -0800
Subject: [PATCH] Implement `unordered_multimap::contains()`

---
 include/boost/unordered/unordered_map.hpp | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/include/boost/unordered/unordered_map.hpp b/include/boost/unordered/unordered_map.hpp
index a7765fe7..bc3608e8 100644
--- a/include/boost/unordered/unordered_map.hpp
+++ b/include/boost/unordered/unordered_map.hpp
@@ -1502,6 +1502,23 @@ namespace boost {
       const_iterator find(CompatibleKey const&, CompatibleHash const&,
         CompatiblePredicate const&) const;
 
+      bool contains(key_type const& k) const
+      {
+        return table_.find_node_impl(
+          table::policy::apply_hash(this->hash_function(), k), k,
+          this->key_eq());
+      }
+
+      template <class Key>
+      typename boost::enable_if_c<detail::are_transparent<Key, H, P>::value,
+        bool>::type
+      contains(const Key& k) const
+      {
+        return table_.find_node_impl(
+          table::policy::apply_hash(this->hash_function(), k), k,
+          this->key_eq());
+      }
+
       size_type count(const key_type&) const;
 
       template <class Key>