From 29323399657194e8968656ab85b47139ca722ec2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ion=20Gazta=C3=B1aga?= <igaztanaga@gmail.com>
Date: Mon, 3 Nov 2025 23:55:52 +0100
Subject: [PATCH] Fix transparent erase signature to "K&&"

---
 include/boost/container/detail/flat_tree.hpp | 3 ++-
 include/boost/container/detail/tree.hpp      | 7 +++++--
 include/boost/container/flat_map.hpp         | 2 +-
 include/boost/container/map.hpp              | 2 +-
 4 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/include/boost/container/detail/flat_tree.hpp b/include/boost/container/detail/flat_tree.hpp
index a753a45..2c7ce04 100644
--- a/include/boost/container/detail/flat_tree.hpp
+++ b/include/boost/container/detail/flat_tree.hpp
@@ -1175,8 +1175,9 @@ class flat_tree
       !dtl::is_convertible<K, iterator>::value &&     //not convertible to iterator
       !dtl::is_convertible<K, const_iterator>::value  //not convertible to const_iterator
       , size_type>::type
-      erase(const K& k)
+      erase(BOOST_FWD_REF(K) key)
    {
+      const typename remove_cvref<K>::type & k = key;  //Support emulated rvalue references
       std::pair<iterator, iterator > itp = this->equal_range(k);
       size_type ret = static_cast<size_type>(itp.second - itp.first);
       if (ret) {
diff --git a/include/boost/container/detail/tree.hpp b/include/boost/container/detail/tree.hpp
index fc61af7..e762634 100644
--- a/include/boost/container/detail/tree.hpp
+++ b/include/boost/container/detail/tree.hpp
@@ -1152,8 +1152,11 @@ class tree
       !dtl::is_convertible<K, iterator>::value &&     //not convertible to iterator
       !dtl::is_convertible<K, const_iterator>::value  //not convertible to const_iterator
       , size_type>::type
-      erase(const K& k)
-   {  return AllocHolder::erase_key(k, KeyNodeCompare(key_comp()), alloc_version()); }
+      erase(BOOST_FWD_REF(K) key)
+   {
+      const typename remove_cvref<K>::type & k = key;  //Support emulated rvalue references
+      return AllocHolder::erase_key(k, KeyNodeCompare(key_comp()), alloc_version());
+   }
 
    template <class K>
    inline typename dtl::enable_if_c<
diff --git a/include/boost/container/flat_map.hpp b/include/boost/container/flat_map.hpp
index 0879079..8df40ef 100644
--- a/include/boost/container/flat_map.hpp
+++ b/include/boost/container/flat_map.hpp
@@ -1333,7 +1333,7 @@ class flat_map
       !dtl::is_convertible<K BOOST_MOVE_I iterator>::value &&     //not convertible to iterator
       !dtl::is_convertible<K BOOST_MOVE_I const_iterator>::value  //not convertible to const_iterator
       BOOST_MOVE_I size_type>::type)
-      erase(const K& x)
+      erase(BOOST_FWD_REF(K) x)
    {  return m_flat_tree.erase_unique(x); }
 
    //! <b>Effects</b>: Erases all the elements in the range [first, last).
diff --git a/include/boost/container/map.hpp b/include/boost/container/map.hpp
index dde6035..0b0f498 100644
--- a/include/boost/container/map.hpp
+++ b/include/boost/container/map.hpp
@@ -1032,7 +1032,7 @@ class map
             !dtl::is_convertible<K BOOST_MOVE_I iterator>::value &&     //not convertible to iterator
             !dtl::is_convertible<K BOOST_MOVE_I const_iterator>::value  //not convertible to const_iterator
             BOOST_MOVE_I size_type>::type)
-      erase(const K& x)
+      erase(BOOST_FWD_REF(K) x)
       { return this->base_t::erase_unique(x); }
 
    #if defined(BOOST_CONTAINER_DOXYGEN_INVOKED)