get:
Show a patch.

patch:
Update a patch.

put:
Update a patch.

GET /api/1.2/patches/2226289/?format=api
HTTP 200 OK
Allow: GET, PUT, PATCH, HEAD, OPTIONS
Content-Type: application/json
Vary: Accept

{
    "id": 2226289,
    "url": "http://patchwork.ozlabs.org/api/1.2/patches/2226289/?format=api",
    "web_url": "http://patchwork.ozlabs.org/project/gcc/patch/bmm.hhublw6j3q.gcc.gcc-TEST.fdumont.27.1.1@forge-stage.sourceware.org/",
    "project": {
        "id": 17,
        "url": "http://patchwork.ozlabs.org/api/1.2/projects/17/?format=api",
        "name": "GNU Compiler Collection",
        "link_name": "gcc",
        "list_id": "gcc-patches.gcc.gnu.org",
        "list_email": "gcc-patches@gcc.gnu.org",
        "web_url": null,
        "scm_url": null,
        "webscm_url": null,
        "list_archive_url": "",
        "list_archive_url_format": "",
        "commit_url_format": ""
    },
    "msgid": "<bmm.hhublw6j3q.gcc.gcc-TEST.fdumont.27.1.1@forge-stage.sourceware.org>",
    "list_archive_url": null,
    "date": "2026-04-22T10:38:43",
    "name": "[v1,1/1] libstdc++: Add fancy pointer support in map and set",
    "commit_ref": null,
    "pull_url": null,
    "state": "new",
    "archived": false,
    "hash": "8d6451ec7f1861f198ae162191672f020f590b86",
    "submitter": {
        "id": 93220,
        "url": "http://patchwork.ozlabs.org/api/1.2/people/93220/?format=api",
        "name": "François Dumont via Sourceware Forge",
        "email": "forge-bot+fdumont@forge-stage.sourceware.org"
    },
    "delegate": null,
    "mbox": "http://patchwork.ozlabs.org/project/gcc/patch/bmm.hhublw6j3q.gcc.gcc-TEST.fdumont.27.1.1@forge-stage.sourceware.org/mbox/",
    "series": [
        {
            "id": 500988,
            "url": "http://patchwork.ozlabs.org/api/1.2/series/500988/?format=api",
            "web_url": "http://patchwork.ozlabs.org/project/gcc/list/?series=500988",
            "date": "2026-04-22T10:38:42",
            "name": "libstdc++: Add fancy pointer support in map and set",
            "version": 1,
            "mbox": "http://patchwork.ozlabs.org/series/500988/mbox/"
        }
    ],
    "comments": "http://patchwork.ozlabs.org/api/patches/2226289/comments/",
    "check": "pending",
    "checks": "http://patchwork.ozlabs.org/api/patches/2226289/checks/",
    "tags": {},
    "related": [],
    "headers": {
        "Return-Path": "<gcc-patches-bounces~incoming=patchwork.ozlabs.org@gcc.gnu.org>",
        "X-Original-To": [
            "incoming@patchwork.ozlabs.org",
            "gcc-patches@gcc.gnu.org"
        ],
        "Delivered-To": [
            "patchwork-incoming@legolas.ozlabs.org",
            "gcc-patches@gcc.gnu.org"
        ],
        "Authentication-Results": [
            "legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=gcc.gnu.org\n (client-ip=38.145.34.32; helo=vm01.sourceware.org;\n envelope-from=gcc-patches-bounces~incoming=patchwork.ozlabs.org@gcc.gnu.org;\n receiver=patchwork.ozlabs.org)",
            "sourceware.org; dmarc=none (p=none dis=none)\n header.from=forge-stage.sourceware.org",
            "sourceware.org;\n spf=pass smtp.mailfrom=forge-stage.sourceware.org",
            "server2.sourceware.org;\n arc=none smtp.remote-ip=38.145.34.39"
        ],
        "Received": [
            "from vm01.sourceware.org (vm01.sourceware.org [38.145.34.32])\n\t(using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)\n\t key-exchange x25519 server-signature ECDSA (secp384r1) server-digest SHA384)\n\t(No client certificate requested)\n\tby legolas.ozlabs.org (Postfix) with ESMTPS id 4g0xQy1srBz1yCv\n\tfor <incoming@patchwork.ozlabs.org>; Wed, 22 Apr 2026 21:12:58 +1000 (AEST)",
            "from vm01.sourceware.org (localhost [127.0.0.1])\n\tby sourceware.org (Postfix) with ESMTP id 373B54162851\n\tfor <incoming@patchwork.ozlabs.org>; Wed, 22 Apr 2026 11:12:56 +0000 (GMT)",
            "from forge-stage.sourceware.org (vm08.sourceware.org [38.145.34.39])\n by sourceware.org (Postfix) with ESMTPS id 608F049B0BB8\n for <gcc-patches@gcc.gnu.org>; Wed, 22 Apr 2026 10:39:49 +0000 (GMT)",
            "from forge-stage.sourceware.org (localhost [IPv6:::1])\n (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)\n key-exchange x25519 server-signature ECDSA (prime256v1) server-digest SHA256)\n (No client certificate requested)\n by forge-stage.sourceware.org (Postfix) with ESMTPS id 3D62042B6D\n for <gcc-patches@gcc.gnu.org>; Wed, 22 Apr 2026 10:39:49 +0000 (UTC)"
        ],
        "DKIM-Filter": [
            "OpenDKIM Filter v2.11.0 sourceware.org 373B54162851",
            "OpenDKIM Filter v2.11.0 sourceware.org 608F049B0BB8"
        ],
        "DMARC-Filter": "OpenDMARC Filter v1.4.2 sourceware.org 608F049B0BB8",
        "ARC-Filter": "OpenARC Filter v1.0.0 sourceware.org 608F049B0BB8",
        "ARC-Seal": "i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1776854389; cv=none;\n b=a99IngsAKzce/sXvFtykkF/cGoxJbl6piQ1HX/m/v+TqfXkXPdWMT6uAgS+/r4GOko64fXnMhVbuozbwIAgKOeUTgp6qthDpKkJ1VaJtYFB9Z2IsN2/IiL0Jf6cpiGNuq7b9nhxznYMNT6gFgJUyOK48p++S07GSlR60LJX1DaE=",
        "ARC-Message-Signature": "i=1; a=rsa-sha256; d=sourceware.org; s=key;\n t=1776854389; c=relaxed/simple;\n bh=dJNT4Owz7it92yE115+BJXkXiymdjDlHW3/ihh3OfOo=;\n h=From:Date:Subject:MIME-Version:To:Message-ID;\n b=LKdkxrC3Ht9X4+z1VVomqIMOQSgqQ301SD7BvuulxhWhYWJ7u0dGqfdpsv6m3xuLG2YIjuWK2OZny+nQz9rIpgS+kTszYlkXuJ/z5Cgwk69gpmOIP1BMV4iWMehZvfamIBDP2i+EL1+Y/+YQf5Rjz3BlwYPMDTaiY3rf0b2poPQ=",
        "ARC-Authentication-Results": "i=1; server2.sourceware.org",
        "From": "=?utf-8?b?PT91dGYtOD9xP0ZyYW49QzM9QTdvaXNfRHVtb250X3ZpYV9Tb3VyY2V3YXJl?=\n\t=?utf-8?b?X0ZvcmdlPz0=?= <forge-bot+fdumont@forge-stage.sourceware.org>",
        "Date": "Wed, 22 Apr 2026 10:38:43 +0000",
        "Subject": "[PATCH v1 1/1] libstdc++: Add fancy pointer support in map and set",
        "MIME-Version": "1.0",
        "Content-Type": "text/plain; charset=UTF-8",
        "Content-Transfer-Encoding": "8bit",
        "To": "gcc-patches mailing list <gcc-patches@gcc.gnu.org>",
        "Message-ID": "\n <bmm.hhublw6j3q.gcc.gcc-TEST.fdumont.27.1.1@forge-stage.sourceware.org>",
        "X-Mailer": "batrachomyomachia",
        "X-Requested-Reviewer": "redi",
        "X-Pull-Request-Organization": "gcc",
        "X-Pull-Request-Repository": "gcc-TEST",
        "X-Pull-Request": "https://forge.sourceware.org/gcc/gcc-TEST/pulls/27",
        "References": "\n <bmm.hhublw6j3q.gcc.gcc-TEST.fdumont.27.1.0@forge-stage.sourceware.org>",
        "In-Reply-To": "\n <bmm.hhublw6j3q.gcc.gcc-TEST.fdumont.27.1.0@forge-stage.sourceware.org>",
        "X-Patch-URL": "\n https://forge.sourceware.org/fdumont/gcc-TEST/commit/8dc5a640903fea624e0f1aaad6cba183ee873196",
        "X-BeenThere": "gcc-patches@gcc.gnu.org",
        "X-Mailman-Version": "2.1.30",
        "Precedence": "list",
        "List-Id": "Gcc-patches mailing list <gcc-patches.gcc.gnu.org>",
        "List-Unsubscribe": "<https://gcc.gnu.org/mailman/options/gcc-patches>,\n <mailto:gcc-patches-request@gcc.gnu.org?subject=unsubscribe>",
        "List-Archive": "<https://gcc.gnu.org/pipermail/gcc-patches/>",
        "List-Post": "<mailto:gcc-patches@gcc.gnu.org>",
        "List-Help": "<mailto:gcc-patches-request@gcc.gnu.org?subject=help>",
        "List-Subscribe": "<https://gcc.gnu.org/mailman/listinfo/gcc-patches>,\n <mailto:gcc-patches-request@gcc.gnu.org?subject=subscribe>",
        "Reply-To": "gcc-patches mailing list <gcc-patches@gcc.gnu.org>,\n fdumont@gcc.gnu.org",
        "Errors-To": "gcc-patches-bounces~incoming=patchwork.ozlabs.org@gcc.gnu.org"
    },
    "content": "From: François Dumont <frs.dumont@gmail.com>\n\nSupport fancy allocator pointer type in std::_Rb_tree<>.\n\nIn case of fancy pointer type the container is now storing the pointer to\n__rb_tree::_Node<_ValPtr> as a pointer to __rb_tree::_Node_base<_VoidPtr>.\n\nMany methods are adapted to take and return _Base_ptr in place of _Link_type\nwhich has been renamed into _Node_ptr.\n\nAs all node are stored as _Base_ptr have all methods working with this type\nand remove _Const_Base_ptr and _Const_Node_ptr and all methods associated with\nit.\n\nlibstdc++-v3/ChangeLog:\n\n\t* include/bits/stl_tree.h\n\t[_GLIBCXX_USE_ALLOC_PTR_FOR_RB_TREE]: New macro to control usage of the\n\tcode required to support fancy allocator pointer type.\n\t(_Rb_tree_node_base::_Const_Base_ptr): Remove.\n\t(_Rb_tree_node_base::_S_minimum, _Rb_tree_node_base::_S_maximum): Remove\n\toverloads for _Const_Base_ptr.\n\t(_Rb_tree_node_base::_M_base_ptr()): New.\n\t(_Rb_tree_node_base::_M_node_ptr<_NodePtr>()): New.\n\t(_Rb_tree_node::_Link_type): Remove.\n\t(__rb_tree::_Node_base<>): New.\n\t(__rb_tree::_Header<>): New.\n\t(__rb_tree::_Node<>): New.\n\t(_Rb_tree_increment(const _Rb_tree_node_base*)): Remove declaration.\n\t(_Rb_tree_decrement(const _Rb_tree_node_base*)): Remove declaration.\n\t(_Rb_tree_iterator<>::_Link_type): Rename into...\n\t(_Rb_tree_iterator<>::_Node_ptr): ...this.\n\t(_Rb_tree_const_iterator<>::_Link_type): Rename into...\n\t(_Rb_tree_const_iterator<>::_Node_ptr): ...this.\n\t(_Rb_tree_const_iterator<>::_M_const_cast): Remove.\n\t(_Rb_tree_const_iterator<>::_M_node): Change type into _Base_ptr.\n\t(__rb_tree::_Iterator<>): New.\n\t(__rb_tree::_Node_traits<>): New.\n\t(_Rb_tree<>::_Node_base, _Rb_tree::_Node): New.\n\t(_Rb_tree<>::_Link_type): Rename into...\n\t(_Rb_tree<>::_Node_ptr): ...this.\n\t(_Rb_tree<>::_Const_Base_ptr, _Rb_tree<>::_Const_Node_ptr): Remove.\n\t(_Rb_tree<>): Adapt to generalize usage of _Base_ptr in place of former\n\t_Link_type now _Node_ptr.\n\t(_Rb_tree<>::_M_mbegin): Remove.\n\t(_Rb_tree<>::_S_left(_Const_Base_ptr)): Remove.\n\t(_Rb_tree<>::_S_right(_Const_Base_ptr)): Remove.\n\t(_Rb_tree<>::_S_maximum(_Const_Base_ptr)): Remove.\n\t(_Rb_tree<>::_S_minimum(_Const_Base_ptr)): Remove.\n\t* testsuite/23_containers/map/allocator/ext_ptr.cc: New test case.\n\t* testsuite/23_containers/multimap/allocator/ext_ptr.cc: New test case.\n\t* testsuite/23_containers/multiset/allocator/ext_ptr.cc: New test case.\n\t* testsuite/23_containers/set/allocator/ext_ptr.cc: New test case.\n\t* testsuite/23_containers/set/requirements/explicit_instantiation/alloc_ptr.cc:\n\tNew test case.\n\t* testsuite/23_containers/set/requirements/explicit_instantiation/alloc_ptr_ignored.cc:\n\tNew test case.\n---\n libstdc++-v3/include/bits/stl_tree.h          | 1376 ++++++++++++-----\n .../23_containers/map/allocator/ext_ptr.cc    |   37 +\n .../multimap/allocator/ext_ptr.cc             |   33 +\n .../multiset/allocator/ext_ptr.cc             |   32 +\n .../23_containers/set/allocator/ext_ptr.cc    |   32 +\n .../explicit_instantiation/alloc_ptr.cc       |   86 ++\n .../alloc_ptr_ignored.cc                      |    4 +\n 7 files changed, 1221 insertions(+), 379 deletions(-)\n create mode 100644 libstdc++-v3/testsuite/23_containers/map/allocator/ext_ptr.cc\n create mode 100644 libstdc++-v3/testsuite/23_containers/multimap/allocator/ext_ptr.cc\n create mode 100644 libstdc++-v3/testsuite/23_containers/multiset/allocator/ext_ptr.cc\n create mode 100644 libstdc++-v3/testsuite/23_containers/set/allocator/ext_ptr.cc\n create mode 100644 libstdc++-v3/testsuite/23_containers/set/requirements/explicit_instantiation/alloc_ptr.cc\n create mode 100644 libstdc++-v3/testsuite/23_containers/set/requirements/explicit_instantiation/alloc_ptr_ignored.cc",
    "diff": "diff --git a/libstdc++-v3/include/bits/stl_tree.h b/libstdc++-v3/include/bits/stl_tree.h\nindex bc27e191e8b8..c87591757e88 100644\n--- a/libstdc++-v3/include/bits/stl_tree.h\n+++ b/libstdc++-v3/include/bits/stl_tree.h\n@@ -66,6 +66,7 @@\n #include <bits/allocator.h>\n #include <bits/stl_function.h>\n #include <bits/cpp_type_traits.h>\n+#include <bits/ptr_traits.h>\n #include <ext/alloc_traits.h>\n #if __cplusplus >= 201103L\n # include <ext/aligned_buffer.h>\n@@ -74,6 +75,13 @@\n # include <bits/node_handle.h>\n #endif\n \n+#if __cplusplus < 201103L\n+# undef _GLIBCXX_USE_ALLOC_PTR_FOR_RB_TREE\n+# define _GLIBCXX_USE_ALLOC_PTR_FOR_RB_TREE 0\n+#elif ! defined _GLIBCXX_USE_ALLOC_PTR_FOR_RB_TREE\n+# define _GLIBCXX_USE_ALLOC_PTR_FOR_RB_TREE 1\n+#endif\n+\n namespace std _GLIBCXX_VISIBILITY(default)\n {\n _GLIBCXX_BEGIN_NAMESPACE_VERSION\n@@ -99,7 +107,6 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n   struct _Rb_tree_node_base\n   {\n     typedef _Rb_tree_node_base* _Base_ptr;\n-    typedef const _Rb_tree_node_base* _Const_Base_ptr;\n \n     _Rb_tree_color\t_M_color;\n     _Base_ptr\t\t_M_parent;\n@@ -113,13 +120,6 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n       return __x;\n     }\n \n-    static _Const_Base_ptr\n-    _S_minimum(_Const_Base_ptr __x) _GLIBCXX_NOEXCEPT\n-    {\n-      while (__x->_M_left != 0) __x = __x->_M_left;\n-      return __x;\n-    }\n-\n     static _Base_ptr\n     _S_maximum(_Base_ptr __x) _GLIBCXX_NOEXCEPT\n     {\n@@ -127,12 +127,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n       return __x;\n     }\n \n-    static _Const_Base_ptr\n-    _S_maximum(_Const_Base_ptr __x) _GLIBCXX_NOEXCEPT\n-    {\n-      while (__x->_M_right != 0) __x = __x->_M_right;\n-      return __x;\n-    }\n+    // This is not const-correct, but it's only used in a const access path\n+    // by std::_Rb_tree::_M_end() where the pointer is used to initialize a\n+    // const_iterator and so constness is restored.\n+    _Base_ptr\n+    _M_base_ptr() const _GLIBCXX_NOEXCEPT\n+    { return const_cast<_Rb_tree_node_base*>(this); }\n   };\n \n   // Helper type offering value initialization guarantee on the compare functor.\n@@ -213,8 +213,6 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n   template<typename _Val>\n     struct _Rb_tree_node : public _Rb_tree_node_base\n     {\n-      typedef _Rb_tree_node<_Val>* _Link_type;\n-\n #if __cplusplus < 201103L\n       _Val _M_value_field;\n \n@@ -236,20 +234,140 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n       _M_valptr() const\n       { return _M_storage._M_ptr(); }\n #endif\n+\n+      _Rb_tree_node*\n+      _M_node_ptr() _GLIBCXX_NOEXCEPT\n+      { return this; }\n+    };\n+\n+#if _GLIBCXX_USE_ALLOC_PTR_FOR_RB_TREE\n+namespace __rb_tree\n+{\n+  template<typename _VoidPtr>\n+    struct _Node_base\n+    {\n+      using _Base_ptr = __ptr_rebind<_VoidPtr, _Node_base>;\n+\n+      _Rb_tree_color\t_M_color;\n+      _Base_ptr\t\t_M_parent;\n+      _Base_ptr\t\t_M_left;\n+      _Base_ptr\t\t_M_right;\n+\n+      static _Base_ptr\n+      _S_minimum(_Base_ptr __x) _GLIBCXX_NOEXCEPT\n+      {\n+\twhile (__x->_M_left) __x = __x->_M_left;\n+\treturn __x;\n+      }\n+\n+      static _Base_ptr\n+      _S_maximum(_Base_ptr __x) _GLIBCXX_NOEXCEPT\n+      {\n+\twhile (__x->_M_right) __x = __x->_M_right;\n+\treturn __x;\n+      }\n+\n+      // This is not const-correct, but it's only used in a const access path\n+      // by std::_Rb_tree::_M_end() where the pointer is used to initialize a\n+      // const_iterator and so constness is restored.\n+      _Base_ptr\n+      _M_base_ptr() const noexcept\n+      {\n+\treturn pointer_traits<_Base_ptr>::pointer_to\n+\t  (*const_cast<_Node_base*>(this));\n+      }\n+    };\n+\n+  // Helper type to manage default initialization of node count and header.\n+  template<typename _NodeBase>\n+    struct _Header\n+    {\n+    private:\n+      using _Base_ptr =  typename _NodeBase::_Base_ptr;\n+\n+    public:\n+      _NodeBase\t\t_M_header;\n+      size_t\t\t_M_node_count; // Keeps track of size of tree.\n+\n+      _Header() noexcept\n+      {\n+\t_M_header._M_color = _S_red;\n+\t_M_reset();\n+      }\n+\n+      _Header(_Header&& __x) noexcept\n+      {\n+\tif (__x._M_header._M_parent)\n+\t  _M_move_data(__x);\n+\telse\n+\t  {\n+\t    _M_header._M_color = _S_red;\n+\t    _M_reset();\n+\t  }\n+      }\n+\n+      void\n+      _M_move_data(_Header& __from)\n+      {\n+\t_M_header._M_color = __from._M_header._M_color;\n+\t_M_header._M_parent = __from._M_header._M_parent;\n+\t_M_header._M_left = __from._M_header._M_left;\n+\t_M_header._M_right = __from._M_header._M_right;\n+\t_M_header._M_parent->_M_parent = _M_header._M_base_ptr();\n+\t_M_node_count = __from._M_node_count;\n+\n+\t__from._M_reset();\n+      }\n+\n+      void\n+      _M_reset()\n+      {\n+\t_M_header._M_parent = nullptr;\n+\t_M_header._M_left = _M_header._M_right = _M_header._M_base_ptr();\n+\t_M_node_count = 0;\n+      }\n     };\n \n+  template<typename _ValPtr>\n+    struct _Node : public __rb_tree::_Node_base<__ptr_rebind<_ValPtr, void>>\n+    {\n+      using value_type = typename pointer_traits<_ValPtr>::element_type;\n+      using _Node_ptr = __ptr_rebind<_ValPtr, _Node>;\n+\n+      _Node() noexcept { }\n+      ~_Node() { }\n+      _Node(_Node&&) = delete;\n+\n+      union _Uninit_storage\n+      {\n+\t_Uninit_storage() noexcept { }\n+\t~_Uninit_storage() { }\n+\n+\tvalue_type _M_data;\n+      };\n+      _Uninit_storage _M_u;\n+\n+      value_type*\n+      _M_valptr()\n+      { return std::addressof(_M_u._M_data); }\n+\n+      value_type const*\n+      _M_valptr() const\n+      { return std::addressof(_M_u._M_data); }\n+\n+      _Node_ptr\n+      _M_node_ptr() noexcept\n+      { return pointer_traits<_Node_ptr>::pointer_to(*this); }\n+    };\n+} // namespace __rb_tree\n+#endif // _GLIBCXX_USE_ALLOC_PTR_FOR_RB_TREE\n+\n   _GLIBCXX_PURE _Rb_tree_node_base*\n   _Rb_tree_increment(_Rb_tree_node_base* __x) throw ();\n \n-  _GLIBCXX_PURE const _Rb_tree_node_base*\n-  _Rb_tree_increment(const _Rb_tree_node_base* __x) throw ();\n-\n   _GLIBCXX_PURE _Rb_tree_node_base*\n   _Rb_tree_decrement(_Rb_tree_node_base* __x) throw ();\n \n-  _GLIBCXX_PURE const _Rb_tree_node_base*\n-  _Rb_tree_decrement(const _Rb_tree_node_base* __x) throw ();\n-\n   template<typename _Tp>\n     struct _Rb_tree_iterator\n     {\n@@ -260,9 +378,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n       typedef bidirectional_iterator_tag iterator_category;\n       typedef ptrdiff_t\t\t\t difference_type;\n \n-      typedef _Rb_tree_iterator<_Tp>\t\t_Self;\n       typedef _Rb_tree_node_base::_Base_ptr\t_Base_ptr;\n-      typedef _Rb_tree_node<_Tp>*\t\t_Link_type;\n+      typedef _Rb_tree_node<_Tp>*\t\t_Node_ptr;\n \n       _Rb_tree_iterator() _GLIBCXX_NOEXCEPT\n       : _M_node() { }\n@@ -273,49 +390,51 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n \n       reference\n       operator*() const _GLIBCXX_NOEXCEPT\n-      { return *static_cast<_Link_type>(_M_node)->_M_valptr(); }\n+      { return *static_cast<_Node_ptr>(_M_node)->_M_valptr(); }\n \n       pointer\n       operator->() const _GLIBCXX_NOEXCEPT\n-      { return static_cast<_Link_type> (_M_node)->_M_valptr(); }\n+      { return static_cast<_Node_ptr>(_M_node)->_M_valptr(); }\n \n-      _Self&\n+      _Rb_tree_iterator&\n       operator++() _GLIBCXX_NOEXCEPT\n       {\n \t_M_node = _Rb_tree_increment(_M_node);\n \treturn *this;\n       }\n \n-      _Self\n+      _Rb_tree_iterator\n       operator++(int) _GLIBCXX_NOEXCEPT\n       {\n-\t_Self __tmp = *this;\n+\t_Rb_tree_iterator __tmp = *this;\n \t_M_node = _Rb_tree_increment(_M_node);\n \treturn __tmp;\n       }\n \n-      _Self&\n+      _Rb_tree_iterator&\n       operator--() _GLIBCXX_NOEXCEPT\n       {\n \t_M_node = _Rb_tree_decrement(_M_node);\n \treturn *this;\n       }\n \n-      _Self\n+      _Rb_tree_iterator\n       operator--(int) _GLIBCXX_NOEXCEPT\n       {\n-\t_Self __tmp = *this;\n+\t_Rb_tree_iterator __tmp = *this;\n \t_M_node = _Rb_tree_decrement(_M_node);\n \treturn __tmp;\n       }\n \n       friend bool\n-      operator==(const _Self& __x, const _Self& __y) _GLIBCXX_NOEXCEPT\n+      operator==(const _Rb_tree_iterator& __x,\n+\t\t const _Rb_tree_iterator& __y) _GLIBCXX_NOEXCEPT\n       { return __x._M_node == __y._M_node; }\n \n #if ! __cpp_lib_three_way_comparison\n       friend bool\n-      operator!=(const _Self& __x, const _Self& __y) _GLIBCXX_NOEXCEPT\n+      operator!=(const _Rb_tree_iterator& __x,\n+\t\t const _Rb_tree_iterator& __y) _GLIBCXX_NOEXCEPT\n       { return __x._M_node != __y._M_node; }\n #endif\n \n@@ -334,9 +453,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n       typedef bidirectional_iterator_tag iterator_category;\n       typedef ptrdiff_t\t\t\t difference_type;\n \n-      typedef _Rb_tree_const_iterator<_Tp>\t\t_Self;\n-      typedef _Rb_tree_node_base::_Const_Base_ptr\t_Base_ptr;\n-      typedef const _Rb_tree_node<_Tp>*\t\t\t_Link_type;\n+      typedef _Rb_tree_node_base::_Base_ptr\t_Base_ptr;\n+      typedef const _Rb_tree_node<_Tp>*\t\t_Node_ptr;\n \n       _Rb_tree_const_iterator() _GLIBCXX_NOEXCEPT\n       : _M_node() { }\n@@ -348,55 +466,53 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n       _Rb_tree_const_iterator(const iterator& __it) _GLIBCXX_NOEXCEPT\n       : _M_node(__it._M_node) { }\n \n-      iterator\n-      _M_const_cast() const _GLIBCXX_NOEXCEPT\n-      { return iterator(const_cast<typename iterator::_Base_ptr>(_M_node)); }\n-\n       reference\n       operator*() const _GLIBCXX_NOEXCEPT\n-      { return *static_cast<_Link_type>(_M_node)->_M_valptr(); }\n+      { return *static_cast<_Node_ptr>(_M_node)->_M_valptr(); }\n \n       pointer\n       operator->() const _GLIBCXX_NOEXCEPT\n-      { return static_cast<_Link_type>(_M_node)->_M_valptr(); }\n+      { return static_cast<_Node_ptr>(_M_node)->_M_valptr(); }\n \n-      _Self&\n+      _Rb_tree_const_iterator&\n       operator++() _GLIBCXX_NOEXCEPT\n       {\n \t_M_node = _Rb_tree_increment(_M_node);\n \treturn *this;\n       }\n \n-      _Self\n+      _Rb_tree_const_iterator\n       operator++(int) _GLIBCXX_NOEXCEPT\n       {\n-\t_Self __tmp = *this;\n+\t_Rb_tree_const_iterator __tmp = *this;\n \t_M_node = _Rb_tree_increment(_M_node);\n \treturn __tmp;\n       }\n \n-      _Self&\n+      _Rb_tree_const_iterator&\n       operator--() _GLIBCXX_NOEXCEPT\n       {\n \t_M_node = _Rb_tree_decrement(_M_node);\n \treturn *this;\n       }\n \n-      _Self\n+      _Rb_tree_const_iterator\n       operator--(int) _GLIBCXX_NOEXCEPT\n       {\n-\t_Self __tmp = *this;\n+\t_Rb_tree_const_iterator __tmp = *this;\n \t_M_node = _Rb_tree_decrement(_M_node);\n \treturn __tmp;\n       }\n \n       friend bool\n-      operator==(const _Self& __x, const _Self& __y) _GLIBCXX_NOEXCEPT\n+      operator==(const _Rb_tree_const_iterator& __x,\n+\t\t const _Rb_tree_const_iterator& __y) _GLIBCXX_NOEXCEPT\n       { return __x._M_node == __y._M_node; }\n \n #if ! __cpp_lib_three_way_comparison\n       friend bool\n-      operator!=(const _Self& __x, const _Self& __y) _GLIBCXX_NOEXCEPT\n+      operator!=(const _Rb_tree_const_iterator& __x,\n+\t\t const _Rb_tree_const_iterator& __y) _GLIBCXX_NOEXCEPT\n       { return __x._M_node != __y._M_node; }\n #endif\n \n@@ -415,6 +531,485 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n   _Rb_tree_rebalance_for_erase(_Rb_tree_node_base* const __z,\n \t\t\t       _Rb_tree_node_base& __header) throw ();\n \n+namespace __rb_tree\n+{\n+#if _GLIBCXX_USE_ALLOC_PTR_FOR_RB_TREE\n+  template<bool _Const, typename _ValPtr>\n+    struct _Iterator\n+    {\n+      template<typename _Tp>\n+\tusing __maybe_const = __conditional_t<_Const, const _Tp, _Tp>;\n+\n+      using __ptr_traits =\tpointer_traits<_ValPtr>;\n+      using value_type =\ttypename __ptr_traits::element_type;\n+      using reference =\t\t__maybe_const<value_type>&;\n+      using pointer =\t\t__maybe_const<value_type>*;\n+\n+      using iterator_category =\tbidirectional_iterator_tag;\n+      using difference_type =\tptrdiff_t;\n+\n+      using _Node = __rb_tree::_Node<_ValPtr>;\n+      using _Node_base = __rb_tree::_Node_base<__ptr_rebind<_ValPtr, void>>;\n+      using _Base_ptr =\t typename _Node_base::_Base_ptr;\n+\n+      _Iterator() noexcept\n+      : _M_node() { }\n+\n+      constexpr explicit\n+      _Iterator(_Base_ptr __x) noexcept\n+      : _M_node(__x) { }\n+\n+      _Iterator(const _Iterator&) = default;\n+      _Iterator& operator=(const _Iterator&) = default;\n+\n+#ifdef __glibcxx_concepts\n+      constexpr\n+      _Iterator(const _Iterator<false, _ValPtr>& __it) requires _Const\n+#else\n+      template<bool _OtherConst,\n+\t       typename = __enable_if_t<_Const && !_OtherConst>>\n+\tconstexpr\n+\t_Iterator(const _Iterator<_OtherConst, _ValPtr>& __it)\n+#endif\n+\t: _M_node(__it._M_node) { }\n+\n+      [[__nodiscard__]]\n+      reference\n+      operator*() const noexcept\n+      { return *static_cast<_Node&>(*_M_node)._M_valptr(); }\n+\n+      [[__nodiscard__]]\n+      pointer\n+      operator->() const noexcept\n+      { return static_cast<_Node&>(*_M_node)._M_valptr(); }\n+\n+      _GLIBCXX14_CONSTEXPR _Iterator&\n+      operator++() noexcept\n+      {\n+\tif (_M_node->_M_right)\n+\t  {\n+\t    _M_node = _M_node->_M_right;\n+\t    while (_M_node->_M_left)\n+\t      _M_node = _M_node->_M_left;\n+\t  }\n+\telse\n+\t  {\n+\t    _Base_ptr __y = _M_node->_M_parent;\n+\t    while (_M_node == __y->_M_right)\n+\t      {\n+\t\t_M_node = __y;\n+\t\t__y = __y->_M_parent;\n+\t      }\n+\t    if (_M_node->_M_right != __y)\n+\t      _M_node = __y;\n+\t  }\n+\n+\treturn *this;\n+      }\n+\n+      _GLIBCXX14_CONSTEXPR _Iterator\n+      operator++(int) noexcept\n+      {\n+\t_Iterator __tmp(this->_M_node);\n+\t++*this;\n+\treturn __tmp;\n+      }\n+\n+      _GLIBCXX14_CONSTEXPR _Iterator&\n+      operator--() noexcept\n+      {\n+\tif (_M_node->_M_color == _S_red\n+\t    && _M_node->_M_parent->_M_parent == _M_node)\n+\t  _M_node = _M_node->_M_right;\n+\telse if (_M_node->_M_left)\n+\t  {\n+\t    _Base_ptr __y = _M_node->_M_left;\n+\t    while (__y->_M_right)\n+\t      __y = __y->_M_right;\n+\t    _M_node = __y;\n+\t  }\n+\telse\n+\t  {\n+\t    _Base_ptr __y = _M_node->_M_parent;\n+\t    while (_M_node == __y->_M_left)\n+\t      {\n+\t\t_M_node = __y;\n+\t\t__y = __y->_M_parent;\n+\t      }\n+\t    _M_node = __y;\n+\t  }\n+\treturn *this;\n+      }\n+\n+      _GLIBCXX14_CONSTEXPR _Iterator\n+      operator--(int) noexcept\n+      {\n+\t_Iterator __tmp(this->_M_node);\n+\t--*this;\n+\treturn __tmp;\n+      }\n+\n+      [[__nodiscard__]]\n+      friend bool\n+      operator==(const _Iterator& __x, const _Iterator& __y) _GLIBCXX_NOEXCEPT\n+      { return __x._M_node == __y._M_node; }\n+\n+#if ! __cpp_lib_three_way_comparison\n+      [[__nodiscard__]]\n+      friend bool\n+      operator!=(const _Iterator& __x, const _Iterator& __y) _GLIBCXX_NOEXCEPT\n+      { return __x._M_node != __y._M_node; }\n+#endif\n+\n+      _Base_ptr _M_node;\n+    };\n+#endif // USE_ALLOC_PTR_FOR_RB_TREE\n+\n+  // Determine the node and iterator types used by std::_Rb_tree.\n+  template<typename _Val, typename _Ptr>\n+    struct _Node_traits;\n+\n+#if _GLIBCXX_USE_ALLOC_PTR_FOR_RB_TREE <= 9000\n+  // Specialization for the simple case where the allocator's pointer type\n+  // is the same type as value_type*.\n+  // For ABI compatibility we can't change the types used for this case.\n+  template<typename _Val>\n+    struct _Node_traits<_Val, _Val*>\n+    {\n+      typedef _Rb_tree_node<_Val>\t\t_Node;\n+      typedef _Node*\t\t\t\t_Node_ptr;\n+      typedef _Rb_tree_node_base\t\t_Node_base;\n+      typedef _Node_base*\t\t\t_Base_ptr;\n+      typedef _Rb_tree_header\t\t\t_Header_t;\n+      typedef _Rb_tree_iterator<_Val>\t\t_Iterator;\n+      typedef _Rb_tree_const_iterator<_Val>\t_Const_iterator;\n+\n+      __attribute__((__nonnull__))\n+      static void\n+      _S_insert_and_rebalance(const bool __insert_left,\n+\t\t\t      _Node_base* __x, _Node_base* __p,\n+\t\t\t      _Node_base& __header) _GLIBCXX_USE_NOEXCEPT\n+      {\n+\treturn _Rb_tree_insert_and_rebalance(__insert_left, __x, __p, __header);\n+      }\n+\n+      __attribute__((__nonnull__,__returns_nonnull__))\n+      static _Node_base*\n+      _S_rebalance_for_erase(_Node_base* const __z,\n+\t\t\t     _Node_base& __header) _GLIBCXX_USE_NOEXCEPT\n+      { return _Rb_tree_rebalance_for_erase(__z, __header); }\n+    };\n+#endif\n+\n+#if ! _GLIBCXX_USE_ALLOC_PTR_FOR_RB_TREE\n+  // Always use the T* specialization.\n+  template<typename _Val, typename _Ptr>\n+    struct _Node_traits\n+    : _Node_traits<_Val, _Val*>\n+    { };\n+#else\n+  // Primary template used when the allocator uses fancy pointers.\n+  template<typename _Val, typename _ValPtr>\n+    struct _Node_traits\n+    {\n+      using _Node = __rb_tree::_Node<_ValPtr>;\n+      using _Node_ptr = __ptr_rebind<_ValPtr, _Node>;\n+      using _Node_base = __rb_tree::_Node_base<__ptr_rebind<_ValPtr, void>>;\n+      using _Base_ptr = __ptr_rebind<_ValPtr, _Node_base>;\n+      using _Header_t = __rb_tree::_Header<_Node_base>;\n+      using _Iterator = __rb_tree::_Iterator<false, _ValPtr>;\n+      using _Const_iterator = __rb_tree::_Iterator<true, _ValPtr>;\n+\n+      static void\n+      _Rotate_left(_Base_ptr __x, _Base_ptr& __root)\n+      {\n+\tconst _Base_ptr __y = __x->_M_right;\n+\n+\t__x->_M_right = __y->_M_left;\n+\tif (__y->_M_left)\n+\t  __y->_M_left->_M_parent = __x;\n+\t__y->_M_parent = __x->_M_parent;\n+\n+\tif (__x == __root)\n+\t  __root = __y;\n+\telse if (__x == __x->_M_parent->_M_left)\n+\t  __x->_M_parent->_M_left = __y;\n+\telse\n+\t  __x->_M_parent->_M_right = __y;\n+\t__y->_M_left = __x;\n+\t__x->_M_parent = __y;\n+      }\n+\n+      static void\n+      _Rotate_right(_Base_ptr __x, _Base_ptr& __root)\n+      {\n+\tconst _Base_ptr __y = __x->_M_left;\n+\n+\t__x->_M_left = __y->_M_right;\n+\tif (__y->_M_right)\n+\t  __y->_M_right->_M_parent = __x;\n+\t__y->_M_parent = __x->_M_parent;\n+\n+\tif (__x == __root)\n+\t  __root = __y;\n+\telse if (__x == __x->_M_parent->_M_right)\n+\t  __x->_M_parent->_M_right = __y;\n+\telse\n+\t  __x->_M_parent->_M_left = __y;\n+\t__y->_M_right = __x;\n+\t__x->_M_parent = __y;\n+      }\n+\n+      static void\n+      _S_insert_and_rebalance(const bool __insert_left,\n+\t\t\t      _Base_ptr __x, _Base_ptr __p,\n+\t\t\t      _Node_base& __header)\n+      {\n+\t_Base_ptr& __root = __header._M_parent;\n+\n+\t// Initialize fields in new node to insert.\n+\t__x->_M_parent = __p;\n+\t__x->_M_left = __x->_M_right = nullptr;\n+\t__x->_M_color = _S_red;\n+\n+\t// Insert.\n+\t// Make new node child of parent and maintain root, leftmost and\n+\t// rightmost nodes.\n+\t// N.B. First node is always inserted left.\n+\tif (__insert_left)\n+\t  {\n+\t    __p->_M_left = __x; // also makes leftmost = __x when __p == &__header\n+\n+\t    if (std::__to_address(__p) == std::addressof(__header))\n+\t      {\n+\t\t__header._M_parent = __x;\n+\t\t__header._M_right = __x;\n+\t      }\n+\t    else if (__p == __header._M_left)\n+\t      __header._M_left = __x; // maintain leftmost pointing to min node\n+\t  }\n+\telse\n+\t  {\n+\t    __p->_M_right = __x;\n+\n+\t    if (__p == __header._M_right)\n+\t      __header._M_right = __x; // maintain rightmost pointing to max node\n+\t  }\n+\t// Rebalance.\n+\twhile (__x != __root\n+\t       && __x->_M_parent->_M_color == _S_red)\n+\t  {\n+\t    const _Base_ptr __xpp = __x->_M_parent->_M_parent;\n+\n+\t    if (__x->_M_parent == __xpp->_M_left)\n+\t      {\n+\t\tconst _Base_ptr __y = __xpp->_M_right;\n+\t\tif (__y && __y->_M_color == _S_red)\n+\t\t  {\n+\t\t    __x->_M_parent->_M_color = _S_black;\n+\t\t    __y->_M_color = _S_black;\n+\t\t    __xpp->_M_color = _S_red;\n+\t\t    __x = __xpp;\n+\t\t  }\n+\t\telse\n+\t\t  {\n+\t\t    if (__x == __x->_M_parent->_M_right)\n+\t\t      {\n+\t\t\t__x = __x->_M_parent;\n+\t\t\t_Rotate_left(__x, __root);\n+\t\t      }\n+\t\t    __x->_M_parent->_M_color = _S_black;\n+\t\t    __xpp->_M_color = _S_red;\n+\t\t    _Rotate_right(__xpp, __root);\n+\t\t  }\n+\t      }\n+\t    else\n+\t      {\n+\t\tconst _Base_ptr __y = __xpp->_M_left;\n+\t\tif (__y && __y->_M_color == _S_red)\n+\t\t  {\n+\t\t    __x->_M_parent->_M_color = _S_black;\n+\t\t    __y->_M_color = _S_black;\n+\t\t    __xpp->_M_color = _S_red;\n+\t\t    __x = __xpp;\n+\t\t  }\n+\t\telse\n+\t\t  {\n+\t\t    if (__x == __x->_M_parent->_M_left)\n+\t\t      {\n+\t\t\t__x = __x->_M_parent;\n+\t\t\t_Rotate_right(__x, __root);\n+\t\t      }\n+\t\t    __x->_M_parent->_M_color = _S_black;\n+\t\t    __xpp->_M_color = _S_red;\n+\t\t    _Rotate_left(__xpp, __root);\n+\t\t  }\n+\t      }\n+\t  }\n+\t__root->_M_color = _S_black;\n+      }\n+\n+      static _Base_ptr\n+      _S_rebalance_for_erase(_Base_ptr __z, _Node_base& __header)\n+      {\n+\t_Base_ptr& __root = __header._M_parent;\n+\t_Base_ptr& __leftmost = __header._M_left;\n+\t_Base_ptr& __rightmost = __header._M_right;\n+\t_Base_ptr __y = __z;\n+\t_Base_ptr __x{};\n+\t_Base_ptr __x_parent{};\n+\n+\tif (!__y->_M_left)     // __z has at most one non-null child. y == z.\n+\t  __x = __y->_M_right;     // __x might be null.\n+\telse\n+\t  if (!__y->_M_right)  // __z has exactly one non-null child. y == z.\n+\t    __x = __y->_M_left;    // __x is not null.\n+\t  else\n+\t    {\n+\t      // __z has two non-null children.  Set __y to\n+\t      __y = __y->_M_right;   //   __z's successor.  __x might be null.\n+\t      while (__y->_M_left)\n+\t\t__y = __y->_M_left;\n+\t      __x = __y->_M_right;\n+\t    }\n+\tif (__y != __z)\n+\t  {\n+\t    // relink y in place of z.  y is z's successor\n+\t    __z->_M_left->_M_parent = __y;\n+\t    __y->_M_left = __z->_M_left;\n+\t    if (__y != __z->_M_right)\n+\t      {\n+\t\t__x_parent = __y->_M_parent;\n+\t\tif (__x)\n+\t\t  __x->_M_parent = __y->_M_parent;\n+\t\t__y->_M_parent->_M_left = __x;   // __y must be a child of _M_left\n+\t\t__y->_M_right = __z->_M_right;\n+\t\t__z->_M_right->_M_parent = __y;\n+\t      }\n+\t    else\n+\t      __x_parent = __y;\n+\t    if (__root == __z)\n+\t      __root = __y;\n+\t    else if (__z->_M_parent->_M_left == __z)\n+\t      __z->_M_parent->_M_left = __y;\n+\t    else\n+\t      __z->_M_parent->_M_right = __y;\n+\t    __y->_M_parent = __z->_M_parent;\n+\t    std::swap(__y->_M_color, __z->_M_color);\n+\t    __y = __z;\n+\t    // __y now points to node to be actually deleted\n+\t  }\n+\telse\n+\t  {                        // __y == __z\n+\t    __x_parent = __y->_M_parent;\n+\t    if (__x)\n+\t      __x->_M_parent = __y->_M_parent;\n+\t    if (__root == __z)\n+\t      __root = __x;\n+\t    else\n+\t      if (__z->_M_parent->_M_left == __z)\n+\t\t__z->_M_parent->_M_left = __x;\n+\t      else\n+\t\t__z->_M_parent->_M_right = __x;\n+\t    if (__leftmost == __z)\n+\t      {\n+\t\tif (!__z->_M_right)        // __z->_M_left must be null also\n+\t\t  __leftmost = __z->_M_parent;\n+\t\t// makes __leftmost == _M_header if __z == __root\n+\t\telse\n+\t\t  __leftmost = _Node_base::_S_minimum(__x);\n+\t      }\n+\t    if (__rightmost == __z)\n+\t      {\n+\t\tif (__z->_M_left == 0)         // __z->_M_right must be null also\n+\t\t  __rightmost = __z->_M_parent;\n+\t\t// makes __rightmost == _M_header if __z == __root\n+\t\telse                      // __x == __z->_M_left\n+\t\t  __rightmost = _Node_base::_S_maximum(__x);\n+\t      }\n+\t  }\n+\tif (__y->_M_color != _S_red)\n+\t  {\n+\t    while (__x != __root && (__x == 0 || __x->_M_color == _S_black))\n+\t      if (__x == __x_parent->_M_left)\n+\t\t{\n+\t\t  _Base_ptr __w = __x_parent->_M_right;\n+\t\t  if (__w->_M_color == _S_red)\n+\t\t    {\n+\t\t      __w->_M_color = _S_black;\n+\t\t      __x_parent->_M_color = _S_red;\n+\t\t      _Rotate_left(__x_parent, __root);\n+\t\t      __w = __x_parent->_M_right;\n+\t\t    }\n+\t\t  if ((!__w->_M_left || __w->_M_left->_M_color == _S_black) &&\n+\t\t      (!__w->_M_right || __w->_M_right->_M_color == _S_black))\n+\t\t    {\n+\t\t      __w->_M_color = _S_red;\n+\t\t      __x = __x_parent;\n+\t\t      __x_parent = __x_parent->_M_parent;\n+\t\t    }\n+\t\t  else\n+\t\t    {\n+\t\t      if (!__w->_M_right || __w->_M_right->_M_color == _S_black)\n+\t\t\t{\n+\t\t\t  __w->_M_left->_M_color = _S_black;\n+\t\t\t  __w->_M_color = _S_red;\n+\t\t\t  _Rotate_right(__w, __root);\n+\t\t\t  __w = __x_parent->_M_right;\n+\t\t\t}\n+\t\t      __w->_M_color = __x_parent->_M_color;\n+\t\t      __x_parent->_M_color = _S_black;\n+\t\t      if (__w->_M_right)\n+\t\t\t__w->_M_right->_M_color = _S_black;\n+\t\t      _Rotate_left(__x_parent, __root);\n+\t\t      break;\n+\t\t    }\n+\t\t}\n+\t      else\n+\t\t{\n+\t\t  // same as above, with _M_right <-> _M_left.\n+\t\t  _Base_ptr __w = __x_parent->_M_left;\n+\t\t  if (__w->_M_color == _S_red)\n+\t\t    {\n+\t\t      __w->_M_color = _S_black;\n+\t\t      __x_parent->_M_color = _S_red;\n+\t\t      _Rotate_right(__x_parent, __root);\n+\t\t      __w = __x_parent->_M_left;\n+\t\t    }\n+\t\t  if ((!__w->_M_right || __w->_M_right->_M_color == _S_black) &&\n+\t\t      (!__w->_M_left || __w->_M_left->_M_color == _S_black))\n+\t\t    {\n+\t\t      __w->_M_color = _S_red;\n+\t\t      __x = __x_parent;\n+\t\t      __x_parent = __x_parent->_M_parent;\n+\t\t    }\n+\t\t  else\n+\t\t    {\n+\t\t      if (!__w->_M_left || __w->_M_left->_M_color == _S_black)\n+\t\t\t{\n+\t\t\t  __w->_M_right->_M_color = _S_black;\n+\t\t\t  __w->_M_color = _S_red;\n+\t\t\t  _Rotate_left(__w, __root);\n+\t\t\t  __w = __x_parent->_M_left;\n+\t\t\t}\n+\t\t      __w->_M_color = __x_parent->_M_color;\n+\t\t      __x_parent->_M_color = _S_black;\n+\t\t      if (__w->_M_left)\n+\t\t\t__w->_M_left->_M_color = _S_black;\n+\t\t      _Rotate_right(__x_parent, __root);\n+\t\t      break;\n+\t\t    }\n+\t\t}\n+\t    if (__x)\n+\t      __x->_M_color = _S_black;\n+\t  }\n+\n+\treturn __y;\n+      }\n+    };\n+#endif\n+} // namespace __rb_tree\n+\n #if __cplusplus > 201402L\n   template<typename _Tree1, typename _Cmp2>\n     struct _Rb_tree_merge_helper { };\n@@ -425,15 +1020,23 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n     class _Rb_tree\n     {\n       typedef typename __gnu_cxx::__alloc_traits<_Alloc>::template\n-\trebind<_Rb_tree_node<_Val> >::other _Node_allocator;\n+\trebind<_Val>::other _Val_alloc_type;\n+\n+      typedef __gnu_cxx::__alloc_traits<_Val_alloc_type> _Val_alloc_traits;\n+      typedef typename _Val_alloc_traits::pointer _ValPtr;\n+      typedef __rb_tree::_Node_traits<_Val, _ValPtr> _Node_traits;\n+\n+      typedef typename _Node_traits::_Node_base\t\t_Node_base;\n+      typedef typename _Node_traits::_Node\t\t_Node;\n+\n+      typedef typename __gnu_cxx::__alloc_traits<_Alloc>::template\n+\trebind<_Node>::other _Node_allocator;\n \n-      typedef __gnu_cxx::__alloc_traits<_Node_allocator> _Alloc_traits;\n+      typedef __gnu_cxx::__alloc_traits<_Node_allocator> _Node_alloc_traits;\n \n     protected:\n-      typedef _Rb_tree_node_base* \t\t_Base_ptr;\n-      typedef const _Rb_tree_node_base* \t_Const_Base_ptr;\n-      typedef _Rb_tree_node<_Val>* \t\t_Link_type;\n-      typedef const _Rb_tree_node<_Val>*\t_Const_Link_type;\n+      typedef typename _Node_traits::_Base_ptr\t_Base_ptr;\n+      typedef typename _Node_traits::_Node_ptr\t_Node_ptr;\n \n     private:\n       // Functor recycling a pool of nodes and using allocation once the pool\n@@ -445,13 +1048,13 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n \t{\n \t  if (_M_root)\n \t    {\n-\t      _M_root->_M_parent = 0;\n+\t      _M_root->_M_parent = _Base_ptr();\n \n \t      if (_M_nodes->_M_left)\n \t\t_M_nodes = _M_nodes->_M_left;\n \t    }\n \t  else\n-\t    _M_nodes = 0;\n+\t    _M_nodes = _Base_ptr();\n \t}\n \n #if __cplusplus >= 201103L\n@@ -459,15 +1062,19 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n #endif\n \n \t~_Reuse_or_alloc_node()\n-\t{ _M_t._M_erase(static_cast<_Link_type>(_M_root)); }\n+\t{\n+\t  if (_M_root)\n+\t    _M_t._M_erase(static_cast<_Node&>(*_M_root)._M_node_ptr());\n+\t}\n \n \ttemplate<typename _Arg>\n-\t  _Link_type\n+\t  _Node_ptr\n \t  operator()(_GLIBCXX_FWDREF(_Arg) __arg)\n \t  {\n-\t    _Link_type __node = static_cast<_Link_type>(_M_extract());\n-\t    if (__node)\n+\t    _Base_ptr __base = _M_extract();\n+\t    if (__base)\n \t      {\n+\t\t_Node_ptr __node = static_cast<_Node&>(*__base)._M_node_ptr();\n \t\t_M_t._M_destroy_node(__node);\n \t\t_M_t._M_construct_node(__node, _GLIBCXX_FORWARD(_Arg, __arg));\n \t\treturn __node;\n@@ -489,7 +1096,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n \t    {\n \t      if (_M_nodes->_M_right == __node)\n \t\t{\n-\t\t  _M_nodes->_M_right = 0;\n+\t\t  _M_nodes->_M_right = _Base_ptr();\n \n \t\t  if (_M_nodes->_M_left)\n \t\t    {\n@@ -503,10 +1110,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n \t\t    }\n \t\t}\n \t      else // __node is on the left.\n-\t\t_M_nodes->_M_left = 0;\n+\t\t_M_nodes->_M_left = _Base_ptr();\n \t    }\n \t  else\n-\t    _M_root = 0;\n+\t    _M_root = _Base_ptr();\n \n \t  return __node;\n \t}\n@@ -524,7 +1131,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n \t: _M_t(__t) { }\n \n \ttemplate<typename _Arg>\n-\t  _Link_type\n+\t  _Node_ptr\n \t  operator()(_GLIBCXX_FWDREF(_Arg) __arg) const\n \t  { return _M_t._M_create_node(_GLIBCXX_FORWARD(_Arg, __arg)); }\n \n@@ -556,17 +1163,52 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n       { return allocator_type(_M_get_Node_allocator()); }\n \n     protected:\n-      _Link_type\n+      _Node_ptr\n       _M_get_node()\n-      { return _Alloc_traits::allocate(_M_get_Node_allocator(), 1); }\n+      {\n+#if __cplusplus < 201102L || _GLIBCXX_USE_ALLOC_PTR_FOR_RB_TREE\n+\treturn _Node_alloc_traits::allocate(_M_get_Node_allocator(), 1);\n+#else\n+#pragma GCC diagnostic push\n+#pragma GCC diagnostic ignored \"-Wc++17-extensions\" // if constexpr\n+\tusing __alloc_pointer = typename _Node_alloc_traits::pointer;\n+\tif constexpr (is_same<_Node_ptr, __alloc_pointer>::value)\n+\t  return _Node_alloc_traits::allocate(_M_get_Node_allocator(), 1);\n+\telse\n+\t  {\n+\t    auto __ptr =\n+\t      _Node_alloc_traits::allocate(_M_get_Node_allocator(), 1);\n+\t    return std::__to_address(__ptr);\n+\t  }\n+#pragma GCC diagnostic pop\n+#endif\n+      }\n \n       void\n-      _M_put_node(_Link_type __p) _GLIBCXX_NOEXCEPT\n-      { _Alloc_traits::deallocate(_M_get_Node_allocator(), __p, 1); }\n+      _M_put_node(_Node_ptr __p) _GLIBCXX_NOEXCEPT\n+      {\n+#if __cplusplus < 201102L || _GLIBCXX_USE_ALLOC_PTR_FOR_RB_TREE\n+\t_Node_alloc_traits::deallocate(_M_get_Node_allocator(), __p, 1);\n+#else\n+#pragma GCC diagnostic push\n+#pragma GCC diagnostic ignored \"-Wc++17-extensions\" // if constexpr\n+\tusing __alloc_pointer = typename _Node_alloc_traits::pointer;\n+\tif constexpr (is_same<_Node_ptr, __alloc_pointer>::value)\n+\t  _Node_alloc_traits::deallocate(_M_get_Node_allocator(), __p, 1);\n+\telse\n+\t  {\n+\t    // When not using the allocator's pointer type internally we must\n+\t    // convert __p to __alloc_pointer so it can be deallocated.\n+\t    auto __ap = pointer_traits<__alloc_pointer>::pointer_to(*__p);\n+\t    _Node_alloc_traits::deallocate(_M_get_Node_allocator(), __ap, 1);\n+\t  }\n+#pragma GCC diagnostic pop\n+#endif\n+      }\n \n #if __cplusplus < 201103L\n       void\n-      _M_construct_node(_Link_type __node, const value_type& __x)\n+      _M_construct_node(_Node_ptr __node, const value_type& __x)\n       {\n \t__try\n \t  { get_allocator().construct(__node->_M_valptr(), __x); }\n@@ -577,79 +1219,80 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n \t  }\n       }\n \n-      _Link_type\n+      _Node_ptr\n       _M_create_node(const value_type& __x)\n       {\n-\t_Link_type __tmp = _M_get_node();\n+\t_Node_ptr __tmp = _M_get_node();\n \t_M_construct_node(__tmp, __x);\n \treturn __tmp;\n       }\n #else\n       template<typename... _Args>\n \tvoid\n-\t_M_construct_node(_Link_type __node, _Args&&... __args)\n+\t_M_construct_node(_Node_ptr __node, _Args&&... __args)\n \t{\n \t  __try\n \t    {\n-\t      ::new(__node) _Rb_tree_node<_Val>;\n-\t      _Alloc_traits::construct(_M_get_Node_allocator(),\n-\t\t\t\t       __node->_M_valptr(),\n-\t\t\t\t       std::forward<_Args>(__args)...);\n+\t      ::new(std::addressof(*__node)) _Node;\n+\t      _Node_alloc_traits::construct(_M_get_Node_allocator(),\n+\t\t\t\t\t    __node->_M_valptr(),\n+\t\t\t\t\t    std::forward<_Args>(__args)...);\n \t    }\n \t  __catch(...)\n \t    {\n-\t      __node->~_Rb_tree_node<_Val>();\n+\t      __node->~_Node();\n \t      _M_put_node(__node);\n \t      __throw_exception_again;\n \t    }\n \t}\n \n       template<typename... _Args>\n-\t_Link_type\n+\t_Node_ptr\n \t_M_create_node(_Args&&... __args)\n \t{\n-\t  _Link_type __tmp = _M_get_node();\n+\t  _Node_ptr __tmp = _M_get_node();\n \t  _M_construct_node(__tmp, std::forward<_Args>(__args)...);\n \t  return __tmp;\n \t}\n #endif\n \n       void\n-      _M_destroy_node(_Link_type __p) _GLIBCXX_NOEXCEPT\n+      _M_destroy_node(_Node_ptr __p) _GLIBCXX_NOEXCEPT\n       {\n #if __cplusplus < 201103L\n \tget_allocator().destroy(__p->_M_valptr());\n #else\n-\t_Alloc_traits::destroy(_M_get_Node_allocator(), __p->_M_valptr());\n-\t__p->~_Rb_tree_node<_Val>();\n+\t_Node_alloc_traits::destroy(_M_get_Node_allocator(), __p->_M_valptr());\n+\t__p->~_Node();\n #endif\n       }\n \n       void\n-      _M_drop_node(_Link_type __p) _GLIBCXX_NOEXCEPT\n+      _M_drop_node(_Node_ptr __p) _GLIBCXX_NOEXCEPT\n       {\n \t_M_destroy_node(__p);\n \t_M_put_node(__p);\n       }\n \n       template<bool _MoveValue, typename _NodeGen>\n-\t_Link_type\n-\t_M_clone_node(_Link_type __x, _NodeGen& __node_gen)\n+\t_Node_ptr\n+\t_M_clone_node(_Node_ptr __x, _NodeGen& __node_gen)\n \t{\n #if __cplusplus >= 201103L\n \t  using _Vp = __conditional_t<_MoveValue,\n \t\t\t\t      value_type&&,\n \t\t\t\t      const value_type&>;\n #endif\n-\t  _Link_type __tmp\n+\t  _Node_ptr __tmp\n \t    = __node_gen(_GLIBCXX_FORWARD(_Vp, *__x->_M_valptr()));\n \t  __tmp->_M_color = __x->_M_color;\n-\t  __tmp->_M_left = 0;\n-\t  __tmp->_M_right = 0;\n+\t  __tmp->_M_left = __tmp->_M_right = _Base_ptr();\n \t  return __tmp;\n \t}\n \n     protected:\n+      typedef typename _Node_traits::_Header_t\t\t_Header_t;\n+\n #if _GLIBCXX_INLINE_VERSION\n       template<typename _Key_compare>\n #else\n@@ -660,7 +1303,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n \tstruct _Rb_tree_impl\n \t: public _Node_allocator\n \t, public _Rb_tree_key_compare<_Key_compare>\n-\t, public _Rb_tree_header\n+\t, public _Header_t\n \t{\n \t  typedef _Rb_tree_key_compare<_Key_compare> _Base_key_compare;\n \n@@ -672,9 +1315,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n \t  { }\n \n \t  _Rb_tree_impl(const _Rb_tree_impl& __x)\n-\t  : _Node_allocator(_Alloc_traits::_S_select_on_copy(__x))\n+\t  : _Node_allocator(_Node_alloc_traits::_S_select_on_copy(__x))\n \t  , _Base_key_compare(__x._M_key_compare)\n-\t  , _Rb_tree_header()\n+\t  , _Header_t()\n \t  { }\n \n #if __cplusplus < 201103L\n@@ -694,7 +1337,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n \t  _Rb_tree_impl(_Rb_tree_impl&& __x, _Node_allocator&& __a)\n \t  : _Node_allocator(std::move(__a)),\n \t    _Base_key_compare(std::move(__x)),\n-\t    _Rb_tree_header(std::move(__x))\n+\t    _Header_t(std::move(__x))\n \t  { }\n \n \t  _Rb_tree_impl(const _Key_compare& __comp, _Node_allocator&& __a)\n@@ -710,7 +1353,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n       _M_root() _GLIBCXX_NOEXCEPT\n       { return this->_M_impl._M_header._M_parent; }\n \n-      _Const_Base_ptr\n+      _Base_ptr\n       _M_root() const _GLIBCXX_NOEXCEPT\n       { return this->_M_impl._M_header._M_parent; }\n \n@@ -718,7 +1361,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n       _M_leftmost() _GLIBCXX_NOEXCEPT\n       { return this->_M_impl._M_header._M_left; }\n \n-      _Const_Base_ptr\n+      _Base_ptr\n       _M_leftmost() const _GLIBCXX_NOEXCEPT\n       { return this->_M_impl._M_header._M_left; }\n \n@@ -726,35 +1369,29 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n       _M_rightmost() _GLIBCXX_NOEXCEPT\n       { return this->_M_impl._M_header._M_right; }\n \n-      _Const_Base_ptr\n+      _Base_ptr\n       _M_rightmost() const _GLIBCXX_NOEXCEPT\n       { return this->_M_impl._M_header._M_right; }\n \n-      _Link_type\n-      _M_mbegin() const _GLIBCXX_NOEXCEPT\n-      { return static_cast<_Link_type>(this->_M_impl._M_header._M_parent); }\n-\n-      _Link_type\n-      _M_begin() _GLIBCXX_NOEXCEPT\n-      { return _M_mbegin(); }\n-\n-      _Const_Link_type\n+      _Base_ptr\n       _M_begin() const _GLIBCXX_NOEXCEPT\n+      { return this->_M_impl._M_header._M_parent; }\n+\n+      _Node_ptr\n+      _M_begin_node() const _GLIBCXX_NOEXCEPT\n       {\n-\treturn static_cast<_Const_Link_type>\n-\t  (this->_M_impl._M_header._M_parent);\n+\t_Base_ptr __begin = this->_M_impl._M_header._M_parent;\n+\treturn __begin\n+\t  ? static_cast<_Node&>(*__begin)._M_node_ptr()\n+\t  : _Node_ptr();\n       }\n \n       _Base_ptr\n-      _M_end() _GLIBCXX_NOEXCEPT\n-      { return &this->_M_impl._M_header; }\n-\n-      _Const_Base_ptr\n       _M_end() const _GLIBCXX_NOEXCEPT\n-      { return &this->_M_impl._M_header; }\n+      { return this->_M_impl._M_header._M_base_ptr(); }\n \n       static const _Key&\n-      _S_key(_Const_Link_type __x)\n+      _S_key(const _Node& __node)\n       {\n #if __cplusplus >= 201103L\n \t// If we're asking for the key we're presumably using the comparison\n@@ -772,48 +1409,44 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n # endif // C++17\n #endif // C++11\n \n-\treturn _KeyOfValue()(*__x->_M_valptr());\n+\treturn _KeyOfValue()(*__node._M_valptr());\n       }\n \n-      static _Link_type\n-      _S_left(_Base_ptr __x) _GLIBCXX_NOEXCEPT\n-      { return static_cast<_Link_type>(__x->_M_left); }\n-\n-      static _Const_Link_type\n-      _S_left(_Const_Base_ptr __x) _GLIBCXX_NOEXCEPT\n-      { return static_cast<_Const_Link_type>(__x->_M_left); }\n-\n-      static _Link_type\n-      _S_right(_Base_ptr __x) _GLIBCXX_NOEXCEPT\n-      { return static_cast<_Link_type>(__x->_M_right); }\n-\n-      static _Const_Link_type\n-      _S_right(_Const_Base_ptr __x) _GLIBCXX_NOEXCEPT\n-      { return static_cast<_Const_Link_type>(__x->_M_right); }\n+      static const _Key&\n+      _S_key(_Base_ptr __x)\n+      { return _S_key(static_cast<const _Node&>(*__x)); }\n \n       static const _Key&\n-      _S_key(_Const_Base_ptr __x)\n-      { return _S_key(static_cast<_Const_Link_type>(__x)); }\n+      _S_key(_Node_ptr __x)\n+      { return _S_key(*__x); }\n \n       static _Base_ptr\n-      _S_minimum(_Base_ptr __x) _GLIBCXX_NOEXCEPT\n-      { return _Rb_tree_node_base::_S_minimum(__x); }\n+      _S_left(_Base_ptr __x) _GLIBCXX_NOEXCEPT\n+      { return __x->_M_left; }\n \n-      static _Const_Base_ptr\n-      _S_minimum(_Const_Base_ptr __x) _GLIBCXX_NOEXCEPT\n-      { return _Rb_tree_node_base::_S_minimum(__x); }\n+      static _Node_ptr\n+      _S_left(_Node_ptr __x)\n+      {\n+\treturn __x->_M_left\n+\t  ? static_cast<_Node&>(*__x->_M_left)._M_node_ptr()\n+\t  : _Node_ptr();\n+      }\n \n       static _Base_ptr\n-      _S_maximum(_Base_ptr __x) _GLIBCXX_NOEXCEPT\n-      { return _Rb_tree_node_base::_S_maximum(__x); }\n+      _S_right(_Base_ptr __x) _GLIBCXX_NOEXCEPT\n+      { return __x->_M_right; }\n \n-      static _Const_Base_ptr\n-      _S_maximum(_Const_Base_ptr __x) _GLIBCXX_NOEXCEPT\n-      { return _Rb_tree_node_base::_S_maximum(__x); }\n+      static _Node_ptr\n+      _S_right(_Node_ptr __x) _GLIBCXX_NOEXCEPT\n+      {\n+\treturn __x->_M_right\n+\t  ? static_cast<_Node&>(*__x->_M_right)._M_node_ptr()\n+\t  : _Node_ptr();\n+      }\n \n     public:\n-      typedef _Rb_tree_iterator<value_type>       iterator;\n-      typedef _Rb_tree_const_iterator<value_type> const_iterator;\n+      typedef typename _Node_traits::_Iterator\t\titerator;\n+      typedef typename _Node_traits::_Const_iterator\tconst_iterator;\n \n       typedef std::reverse_iterator<iterator>       reverse_iterator;\n       typedef std::reverse_iterator<const_iterator> const_reverse_iterator;\n@@ -846,7 +1479,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n \t_M_insert_(_Base_ptr __x, _Base_ptr __y, _Arg&& __v, _NodeGen&);\n \n       iterator\n-      _M_insert_node(_Base_ptr __x, _Base_ptr __y, _Link_type __z);\n+      _M_insert_node(_Base_ptr __x, _Base_ptr __y, _Node_ptr __z);\n \n       template<typename _Arg>\n \titerator\n@@ -857,10 +1490,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n \t_M_insert_equal_lower(_Arg&& __x);\n \n       iterator\n-      _M_insert_lower_node(_Base_ptr __p, _Link_type __z);\n+      _M_insert_lower_node(_Base_ptr __p, _Node_ptr __z);\n \n       iterator\n-      _M_insert_equal_lower_node(_Link_type __z);\n+      _M_insert_equal_lower_node(_Node_ptr __z);\n #else\n       template<typename _NodeGen>\n \titerator\n@@ -879,22 +1512,22 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n       enum { __as_lvalue, __as_rvalue };\n \n       template<bool _MoveValues, typename _NodeGen>\n-\t_Link_type\n-\t_M_copy(_Link_type, _Base_ptr, _NodeGen&);\n+\t_Base_ptr\n+\t_M_copy(_Node_ptr, _Base_ptr, _NodeGen&);\n \n       template<bool _MoveValues, typename _NodeGen>\n-\t_Link_type\n+\t_Base_ptr\n \t_M_copy(const _Rb_tree& __x, _NodeGen& __gen)\n \t{\n-\t  _Link_type __root =\n-\t    _M_copy<_MoveValues>(__x._M_mbegin(), _M_end(), __gen);\n-\t  _M_leftmost() = _S_minimum(__root);\n-\t  _M_rightmost() = _S_maximum(__root);\n+\t  _Base_ptr __root =\n+\t    _M_copy<_MoveValues>(__x._M_begin_node(), _M_end(), __gen);\n+\t  _M_leftmost() = _Node_base::_S_minimum(__root);\n+\t  _M_rightmost() = _Node_base::_S_maximum(__root);\n \t  _M_impl._M_node_count = __x._M_impl._M_node_count;\n \t  return __root;\n \t}\n \n-      _Link_type\n+      _Base_ptr\n       _M_copy(const _Rb_tree& __x)\n       {\n \t_Alloc_node __an(*this);\n@@ -902,22 +1535,14 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n       }\n \n       void\n-      _M_erase(_Link_type __x);\n-\n-      iterator\n-      _M_lower_bound(_Link_type __x, _Base_ptr __y,\n-\t\t     const _Key& __k);\n+      _M_erase(_Node_ptr __x);\n \n-      const_iterator\n-      _M_lower_bound(_Const_Link_type __x, _Const_Base_ptr __y,\n+      _Base_ptr\n+      _M_lower_bound(_Base_ptr __x, _Base_ptr __y,\n \t\t     const _Key& __k) const;\n \n-      iterator\n-      _M_upper_bound(_Link_type __x, _Base_ptr __y,\n-\t\t     const _Key& __k);\n-\n-      const_iterator\n-      _M_upper_bound(_Const_Link_type __x, _Const_Base_ptr __y,\n+      _Base_ptr\n+      _M_upper_bound(_Base_ptr __x, _Base_ptr __y,\n \t\t     const _Key& __k) const;\n \n     public:\n@@ -935,7 +1560,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n       _Rb_tree(const _Rb_tree& __x)\n       : _M_impl(__x._M_impl)\n       {\n-\tif (__x._M_root() != 0)\n+\tif (__x._M_root())\n \t  _M_root() = _M_copy(__x);\n       }\n \n@@ -947,7 +1572,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n       _Rb_tree(const _Rb_tree& __x, const allocator_type& __a)\n       : _M_impl(__x._M_impl._M_key_compare, _Node_allocator(__a))\n       {\n-\tif (__x._M_root() != nullptr)\n+\tif (__x._M_root())\n \t  _M_root() = _M_copy(__x);\n       }\n \n@@ -966,7 +1591,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n       _Rb_tree(_Rb_tree&& __x, _Node_allocator&& __a, false_type)\n       : _M_impl(__x._M_impl._M_key_compare, std::move(__a))\n       {\n-\tif (__x._M_root() != nullptr)\n+\tif (__x._M_root())\n \t  _M_move_data(__x, false_type{});\n       }\n \n@@ -974,14 +1599,14 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n       _Rb_tree(_Rb_tree&& __x, _Node_allocator&& __a)\n       noexcept( noexcept(\n \t_Rb_tree(std::declval<_Rb_tree&&>(), std::declval<_Node_allocator&&>(),\n-\t\t std::declval<typename _Alloc_traits::is_always_equal>())) )\n+\t\t std::declval<typename _Node_alloc_traits::is_always_equal>())) )\n       : _Rb_tree(std::move(__x), std::move(__a),\n-\t\t typename _Alloc_traits::is_always_equal{})\n+\t\t typename _Node_alloc_traits::is_always_equal{})\n       { }\n #endif\n \n       ~_Rb_tree() _GLIBCXX_NOEXCEPT\n-      { _M_erase(_M_begin()); }\n+      { _M_erase(_M_begin_node()); }\n \n       _Rb_tree&\n       operator=(const _Rb_tree& __x);\n@@ -1001,11 +1626,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n \n       iterator\n       end() _GLIBCXX_NOEXCEPT\n-      { return iterator(&this->_M_impl._M_header); }\n+      { return iterator(_M_end()); }\n \n       const_iterator\n       end() const _GLIBCXX_NOEXCEPT\n-      { return const_iterator(&this->_M_impl._M_header); }\n+      { return const_iterator(_M_end()); }\n \n       reverse_iterator\n       rbegin() _GLIBCXX_NOEXCEPT\n@@ -1033,7 +1658,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n \n       size_type\n       max_size() const _GLIBCXX_NOEXCEPT\n-      { return _Alloc_traits::max_size(_M_get_Node_allocator()); }\n+      { return _Node_alloc_traits::max_size(_M_get_Node_allocator()); }\n \n       void\n       swap(_Rb_tree& __t)\n@@ -1194,7 +1819,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n \tconst_iterator __result = __position;\n \t++__result;\n \t_M_erase_aux(__position);\n-\treturn __result._M_const_cast();\n+\treturn iterator(__result._M_node);\n       }\n \n       // LWG 2059.\n@@ -1235,7 +1860,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n       erase(const_iterator __first, const_iterator __last)\n       {\n \t_M_erase_aux(__first, __last);\n-\treturn __last._M_const_cast();\n+\treturn iterator(__last._M_node);\n       }\n #else\n       void\n@@ -1250,7 +1875,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n       void\n       clear() _GLIBCXX_NOEXCEPT\n       {\n-\t_M_erase(_M_begin());\n+\t_M_erase(_M_begin_node());\n \t_M_impl._M_reset();\n       }\n \n@@ -1266,19 +1891,25 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n \n       iterator\n       lower_bound(const key_type& __k)\n-      { return _M_lower_bound(_M_begin(), _M_end(), __k); }\n+      { return iterator(_M_lower_bound(_M_begin(), _M_end(), __k)); }\n \n       const_iterator\n       lower_bound(const key_type& __k) const\n-      { return _M_lower_bound(_M_begin(), _M_end(), __k); }\n+      {\n+\treturn const_iterator\n+\t  (_M_lower_bound(_M_begin(), _M_end(), __k));\n+      }\n \n       iterator\n       upper_bound(const key_type& __k)\n-      { return _M_upper_bound(_M_begin(), _M_end(), __k); }\n+      { return iterator(_M_upper_bound(_M_begin(), _M_end(), __k)); }\n \n       const_iterator\n       upper_bound(const key_type& __k) const\n-      { return _M_upper_bound(_M_begin(), _M_end(), __k); }\n+      {\n+\treturn const_iterator\n+\t  (_M_upper_bound(_M_begin(), _M_end(), __k));\n+      }\n \n       pair<iterator, iterator>\n       equal_range(const key_type& __k);\n@@ -1293,7 +1924,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n \t_M_find_tr(const _Kt& __k)\n \t{\n \t  const _Rb_tree* __const_this = this;\n-\t  return __const_this->_M_find_tr(__k)._M_const_cast();\n+\t  return iterator(__const_this->_M_find_tr(__k)._M_node);\n \t}\n \n       template<typename _Kt,\n@@ -1301,7 +1932,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n \tconst_iterator\n \t_M_find_tr(const _Kt& __k) const\n \t{\n-\t  auto __j = _M_lower_bound_tr(__k);\n+\t  const_iterator __j(_M_lower_bound_tr(__k));\n \t  if (__j != end() && _M_impl._M_key_compare(__k, _S_key(__j._M_node)))\n \t    __j = end();\n \t  return __j;\n@@ -1318,21 +1949,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n \n       template<typename _Kt,\n \t       typename _Req = __has_is_transparent_t<_Compare, _Kt>>\n-\titerator\n-\t_M_lower_bound_tr(const _Kt& __k)\n-\t{\n-\t  const _Rb_tree* __const_this = this;\n-\t  return __const_this->_M_lower_bound_tr(__k)._M_const_cast();\n-\t}\n-\n-      template<typename _Kt,\n-\t       typename _Req = __has_is_transparent_t<_Compare, _Kt>>\n-\tconst_iterator\n+\t_Base_ptr\n \t_M_lower_bound_tr(const _Kt& __k) const\n \t{\n \t  auto __x = _M_begin();\n \t  auto __y = _M_end();\n-\t  while (__x != 0)\n+\t  while (__x)\n \t    if (!_M_impl._M_key_compare(_S_key(__x), __k))\n \t      {\n \t\t__y = __x;\n@@ -1340,26 +1962,17 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n \t      }\n \t    else\n \t      __x = _S_right(__x);\n-\t  return const_iterator(__y);\n-\t}\n-\n-      template<typename _Kt,\n-\t       typename _Req = __has_is_transparent_t<_Compare, _Kt>>\n-\titerator\n-\t_M_upper_bound_tr(const _Kt& __k)\n-\t{\n-\t  const _Rb_tree* __const_this = this;\n-\t  return __const_this->_M_upper_bound_tr(__k)._M_const_cast();\n+\t  return __y;\n \t}\n \n       template<typename _Kt,\n \t       typename _Req = __has_is_transparent_t<_Compare, _Kt>>\n-\tconst_iterator\n+\t_Base_ptr\n \t_M_upper_bound_tr(const _Kt& __k) const\n \t{\n \t  auto __x = _M_begin();\n \t  auto __y = _M_end();\n-\t  while (__x != 0)\n+\t  while (__x)\n \t    if (_M_impl._M_key_compare(__k, _S_key(__x)))\n \t      {\n \t\t__y = __x;\n@@ -1367,7 +1980,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n \t      }\n \t    else\n \t      __x = _S_right(__x);\n-\t  return const_iterator(__y);\n+\t  return __y;\n \t}\n \n       template<typename _Kt,\n@@ -1377,7 +1990,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n \t{\n \t  const _Rb_tree* __const_this = this;\n \t  auto __ret = __const_this->_M_equal_range_tr(__k);\n-\t  return { __ret.first._M_const_cast(), __ret.second._M_const_cast() };\n+\t  return\n+\t    { iterator(__ret.first._M_node), iterator(__ret.second._M_node) };\n \t}\n \n       template<typename _Kt,\n@@ -1385,7 +1999,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n \tpair<const_iterator, const_iterator>\n \t_M_equal_range_tr(const _Kt& __k) const\n \t{\n-\t  auto __low = _M_lower_bound_tr(__k);\n+\t  const_iterator __low(_M_lower_bound_tr(__k));\n \t  auto __high = __low;\n \t  auto& __cmp = _M_impl._M_key_compare;\n \t  while (__high != end() && !__cmp(__k, _S_key(__high._M_node)))\n@@ -1401,7 +2015,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n #if __cplusplus >= 201103L\n       _Rb_tree&\n       operator=(_Rb_tree&&)\n-      noexcept(_Alloc_traits::_S_nothrow_move()\n+      noexcept(_Node_alloc_traits::_S_nothrow_move()\n \t       && is_nothrow_move_assignable<_Compare>::value);\n \n       template<typename _Iterator>\n@@ -1434,6 +2048,23 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n #endif\n \n #if __glibcxx_node_extract // >= C++17\n+      static _Node_ptr\n+      _S_adapt(typename _Node_alloc_traits::pointer __ptr)\n+      {\n+#if _GLIBCXX_USE_ALLOC_PTR_FOR_RB_TREE\n+\treturn __ptr;\n+#else\n+#pragma GCC diagnostic push\n+#pragma GCC diagnostic ignored \"-Wc++17-extensions\" // if constexpr\n+\tusing __alloc_ptr = typename _Node_alloc_traits::pointer;\n+\tif constexpr (is_same<_Node_ptr, __alloc_ptr>::value)\n+\t  return __ptr;\n+\telse\n+\t  return std::__to_address(__ptr);\n+#pragma GCC diagnostic pop\n+#endif\n+      }\n+\n     public:\n       /// Re-insert an extracted node.\n       insert_return_type\n@@ -1450,7 +2081,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n \t    if (__res.second)\n \t      {\n \t\t__ret.position\n-\t\t  = _M_insert_node(__res.first, __res.second, __nh._M_ptr);\n+\t\t  = _M_insert_node(__res.first, __res.second,\n+\t\t\t\t   _S_adapt(__nh._M_ptr));\n \t\t__nh.release();\n \t\t__ret.inserted = true;\n \t      }\n@@ -1476,9 +2108,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n \t    __glibcxx_assert(_M_get_Node_allocator() == *__nh._M_alloc);\n \t    auto __res = _M_get_insert_equal_pos(__nh._M_key());\n \t    if (__res.second)\n-\t      __ret = _M_insert_node(__res.first, __res.second, __nh._M_ptr);\n+\t      __ret = _M_insert_node(__res.first, __res.second,\n+\t\t\t\t     _S_adapt(__nh._M_ptr));\n \t    else\n-\t      __ret = _M_insert_equal_lower_node(__nh._M_ptr);\n+\t      __ret = _M_insert_equal_lower_node(_S_adapt(__nh._M_ptr));\n \t    __nh.release();\n \t  }\n \treturn __ret;\n@@ -1497,7 +2130,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n \t    auto __res = _M_get_insert_hint_unique_pos(__hint, __nh._M_key());\n \t    if (__res.second)\n \t      {\n-\t\t__ret = _M_insert_node(__res.first, __res.second, __nh._M_ptr);\n+\t\t__ret = _M_insert_node(__res.first, __res.second,\n+\t\t\t\t       _S_adapt(__nh._M_ptr));\n \t\t__nh.release();\n \t      }\n \t    else\n@@ -1518,9 +2152,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n \t    __glibcxx_assert(_M_get_Node_allocator() == *__nh._M_alloc);\n \t    auto __res = _M_get_insert_hint_equal_pos(__hint, __nh._M_key());\n \t    if (__res.second)\n-\t      __ret = _M_insert_node(__res.first, __res.second, __nh._M_ptr);\n+\t      __ret = _M_insert_node(__res.first, __res.second,\n+\t\t\t\t     _S_adapt(__nh._M_ptr));\n \t    else\n-\t      __ret = _M_insert_equal_lower_node(__nh._M_ptr);\n+\t      __ret = _M_insert_equal_lower_node(_S_adapt(__nh._M_ptr));\n \t    __nh.release();\n \t  }\n \treturn __ret;\n@@ -1530,10 +2165,25 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n       node_type\n       extract(const_iterator __pos)\n       {\n-\tauto __ptr = _Rb_tree_rebalance_for_erase(\n-\t    __pos._M_const_cast()._M_node, _M_impl._M_header);\n+\tauto __ptr = _Node_traits::_S_rebalance_for_erase\n+\t  (__pos._M_node, _M_impl._M_header);\n \t--_M_impl._M_node_count;\n-\treturn { static_cast<_Link_type>(__ptr), _M_get_Node_allocator() };\n+\tauto __node_ptr = static_cast<_Node&>(*__ptr)._M_node_ptr();\n+#if _GLIBCXX_USE_ALLOC_PTR_FOR_RB_TREE\n+\treturn { __node_ptr, _M_get_Node_allocator() };\n+#else\n+#pragma GCC diagnostic push\n+#pragma GCC diagnostic ignored \"-Wc++17-extensions\" // if constexpr\n+\tusing __alloc_ptr = typename _Node_alloc_traits::pointer;\n+\tif constexpr (is_same<_Node_ptr, __alloc_ptr>::value)\n+\t  return { __node_ptr, _M_get_Node_allocator() };\n+\telse\n+\t  {\n+\t    auto __ap = pointer_traits<__alloc_ptr>::pointer_to(*__node_ptr);\n+\t    return { __ap, _M_get_Node_allocator() };\n+\t  }\n+#pragma GCC diagnostic pop\n+#endif\n       }\n \n       /// Extract a node.\n@@ -1567,11 +2217,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n \t      if (__res.second)\n \t\t{\n \t\t  auto& __src_impl = _Merge_helper::_S_get_impl(__src);\n-\t\t  auto __ptr = _Rb_tree_rebalance_for_erase(\n-\t\t      __pos._M_node, __src_impl._M_header);\n+\t\t  auto __ptr = _Node_traits::_S_rebalance_for_erase\n+\t\t    (__pos._M_node, __src_impl._M_header);\n \t\t  --__src_impl._M_node_count;\n-\t\t  _M_insert_node(__res.first, __res.second,\n-\t\t\t\t static_cast<_Link_type>(__ptr));\n+\t\t  auto __node_ptr = static_cast<_Node&>(*__ptr)._M_node_ptr();\n+\t\t  _M_insert_node(__res.first, __res.second, __node_ptr);\n \t\t}\n \t    }\n \t}\n@@ -1589,11 +2239,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n \t      if (__res.second)\n \t\t{\n \t\t  auto& __src_impl = _Merge_helper::_S_get_impl(__src);\n-\t\t  auto __ptr = _Rb_tree_rebalance_for_erase(\n-\t\t      __pos._M_node, __src_impl._M_header);\n+\t\t  auto __ptr = _Node_traits::_S_rebalance_for_erase\n+\t\t    (__pos._M_node, __src_impl._M_header);\n \t\t  --__src_impl._M_node_count;\n-\t\t  _M_insert_node(__res.first, __res.second,\n-\t\t\t\t static_cast<_Link_type>(__ptr));\n+\t\t  auto __node_ptr = static_cast<_Node&>(*__ptr)._M_node_ptr();\n+\t\t  _M_insert_node(__res.first, __res.second, __node_ptr);\n \t\t}\n \t    }\n \t}\n@@ -1666,7 +2316,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n \t}\n \n \t_Rb_tree& _M_t;\n-\t_Link_type _M_node;\n+\t_Node_ptr _M_node;\n       };\n #endif // C++11\n     };\n@@ -1704,7 +2354,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n     _M_move_assign(_Rb_tree& __x, true_type)\n     {\n       clear();\n-      if (__x._M_root() != nullptr)\n+      if (__x._M_root())\n \t_M_move_data(__x, true_type());\n       std::__alloc_on_move(_M_get_Node_allocator(),\n \t\t\t   __x._M_get_Node_allocator());\n@@ -1723,7 +2373,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n       // structure.\n       _Reuse_or_alloc_node __roan(*this);\n       _M_impl._M_reset();\n-      if (__x._M_root() != nullptr)\n+      if (__x._M_root())\n \t{\n \t  _M_root() = _M_copy<__as_rvalue>(__x, __roan);\n \t  __x.clear();\n@@ -1735,11 +2385,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n     inline _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>&\n     _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::\n     operator=(_Rb_tree&& __x)\n-    noexcept(_Alloc_traits::_S_nothrow_move()\n+    noexcept(_Node_alloc_traits::_S_nothrow_move()\n \t     && is_nothrow_move_assignable<_Compare>::value)\n     {\n       _M_impl._M_key_compare = std::move(__x._M_impl._M_key_compare);\n-      _M_move_assign(__x, __bool_constant<_Alloc_traits::_S_nothrow_move()>());\n+      _M_move_assign(__x,\n+\t\t     __bool_constant<_Node_alloc_traits::_S_nothrow_move()>());\n       return *this;\n     }\n \n@@ -1780,11 +2431,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n \t{\n \t  // Note that _Key may be a constant type.\n #if __cplusplus >= 201103L\n-\t  if (_Alloc_traits::_S_propagate_on_copy_assign())\n+\t  if (_Node_alloc_traits::_S_propagate_on_copy_assign())\n \t    {\n \t      auto& __this_alloc = this->_M_get_Node_allocator();\n \t      auto& __that_alloc = __x._M_get_Node_allocator();\n-\t      if (!_Alloc_traits::_S_always_equal()\n+\t      if (!_Node_alloc_traits::_S_always_equal()\n \t\t  && __this_alloc != __that_alloc)\n \t\t{\n \t\t  // Replacement allocator cannot free existing storage, we need\n@@ -1798,7 +2449,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n \t  _Reuse_or_alloc_node __roan(*this);\n \t  _M_impl._M_reset();\n \t  _M_impl._M_key_compare = __x._M_impl._M_key_compare;\n-\t  if (__x._M_root() != 0)\n+\t  if (__x._M_root())\n \t    _M_root() = _M_copy<__as_lvalue>(__x, __roan);\n \t}\n \n@@ -1822,14 +2473,15 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n #endif\n \t\t _NodeGen& __node_gen)\n       {\n-\tbool __insert_left = (__x != 0 || __p == _M_end()\n+\tbool __insert_left = (__x || __p == _M_end()\n \t\t\t      || _M_impl._M_key_compare(_KeyOfValue()(__v),\n \t\t\t\t\t\t\t_S_key(__p)));\n \n-\t_Link_type __z = __node_gen(_GLIBCXX_FORWARD(_Arg, __v));\n+\t_Base_ptr __z =\n+\t  __node_gen(_GLIBCXX_FORWARD(_Arg, __v))->_M_base_ptr();\n \n-\t_Rb_tree_insert_and_rebalance(__insert_left, __z, __p,\n-\t\t\t\t      this->_M_impl._M_header);\n+\t_Node_traits::_S_insert_and_rebalance\n+\t  (__insert_left, __z, __p, this->_M_impl._M_header);\n \t++_M_impl._M_node_count;\n \treturn iterator(__z);\n       }\n@@ -1851,10 +2503,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n \t\t\t    || !_M_impl._M_key_compare(_S_key(__p),\n \t\t\t\t\t\t       _KeyOfValue()(__v)));\n \n-      _Link_type __z = _M_create_node(_GLIBCXX_FORWARD(_Arg, __v));\n-\n-      _Rb_tree_insert_and_rebalance(__insert_left, __z, __p,\n-\t\t\t\t    this->_M_impl._M_header);\n+      _Base_ptr __z =\n+\t_M_create_node(_GLIBCXX_FORWARD(_Arg, __v))->_M_base_ptr();\n+      _Node_traits::_S_insert_and_rebalance\n+\t(__insert_left, __z, __p, this->_M_impl._M_header);\n       ++_M_impl._M_node_count;\n       return iterator(__z);\n     }\n@@ -1872,9 +2524,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n     _M_insert_equal_lower(const _Val& __v)\n #endif\n     {\n-      _Link_type __x = _M_begin();\n+      _Base_ptr __x = _M_begin();\n       _Base_ptr __y = _M_end();\n-      while (__x != 0)\n+      while (__x)\n \t{\n \t  __y = __x;\n \t  __x = !_M_impl._M_key_compare(_S_key(__x), _KeyOfValue()(__v)) ?\n@@ -1886,25 +2538,27 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n   template<typename _Key, typename _Val, typename _KoV,\n \t   typename _Compare, typename _Alloc>\n     template<bool _MoveValues, typename _NodeGen>\n-      typename _Rb_tree<_Key, _Val, _KoV, _Compare, _Alloc>::_Link_type\n+      typename _Rb_tree<_Key, _Val, _KoV, _Compare, _Alloc>::_Base_ptr\n       _Rb_tree<_Key, _Val, _KoV, _Compare, _Alloc>::\n-      _M_copy(_Link_type __x, _Base_ptr __p, _NodeGen& __node_gen)\n+      _M_copy(_Node_ptr __x, _Base_ptr __p, _NodeGen& __node_gen)\n       {\n \t// Structural copy. __x and __p must be non-null.\n-\t_Link_type __top = _M_clone_node<_MoveValues>(__x, __node_gen);\n+\t_Node_ptr __top = _M_clone_node<_MoveValues>(__x, __node_gen);\n+\t_Base_ptr __top_base = __top->_M_base_ptr();\n \t__top->_M_parent = __p;\n \n \t__try\n \t  {\n \t    if (__x->_M_right)\n \t      __top->_M_right =\n-\t\t_M_copy<_MoveValues>(_S_right(__x), __top, __node_gen);\n-\t    __p = __top;\n+\t\t_M_copy<_MoveValues>(_S_right(__x), __top_base, __node_gen);\n+\t    __p = __top_base;\n \t    __x = _S_left(__x);\n \n-\t    while (__x != 0)\n+\t    while (__x)\n \t      {\n-\t\t_Link_type __y = _M_clone_node<_MoveValues>(__x, __node_gen);\n+\t\t_Base_ptr __y =\n+\t\t  _M_clone_node<_MoveValues>(__x, __node_gen)->_M_base_ptr();\n \t\t__p->_M_left = __y;\n \t\t__y->_M_parent = __p;\n \t\tif (__x->_M_right)\n@@ -1919,20 +2573,20 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n \t    _M_erase(__top);\n \t    __throw_exception_again;\n \t  }\n-\treturn __top;\n+\treturn __top_base;\n       }\n \n   template<typename _Key, typename _Val, typename _KeyOfValue,\n \t   typename _Compare, typename _Alloc>\n     void\n     _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::\n-    _M_erase(_Link_type __x)\n+    _M_erase(_Node_ptr __x)\n     {\n       // Erase without rebalancing.\n-      while (__x != 0)\n+      while (__x)\n \t{\n \t  _M_erase(_S_right(__x));\n-\t  _Link_type __y = _S_left(__x);\n+\t  _Node_ptr __y = _S_left(__x);\n \t  _M_drop_node(__x);\n \t  __x = __y;\n \t}\n@@ -1941,65 +2595,33 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n   template<typename _Key, typename _Val, typename _KeyOfValue,\n \t   typename _Compare, typename _Alloc>\n     typename _Rb_tree<_Key, _Val, _KeyOfValue,\n-\t\t      _Compare, _Alloc>::iterator\n-    _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::\n-    _M_lower_bound(_Link_type __x, _Base_ptr __y,\n-\t\t   const _Key& __k)\n-    {\n-      while (__x != 0)\n-\tif (!_M_impl._M_key_compare(_S_key(__x), __k))\n-\t  __y = __x, __x = _S_left(__x);\n-\telse\n-\t  __x = _S_right(__x);\n-      return iterator(__y);\n-    }\n-\n-  template<typename _Key, typename _Val, typename _KeyOfValue,\n-\t   typename _Compare, typename _Alloc>\n-    typename _Rb_tree<_Key, _Val, _KeyOfValue,\n-\t\t      _Compare, _Alloc>::const_iterator\n+\t\t      _Compare, _Alloc>::_Base_ptr\n     _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::\n-    _M_lower_bound(_Const_Link_type __x, _Const_Base_ptr __y,\n+    _M_lower_bound(_Base_ptr __x, _Base_ptr __y,\n \t\t   const _Key& __k) const\n     {\n-      while (__x != 0)\n+      while (__x)\n \tif (!_M_impl._M_key_compare(_S_key(__x), __k))\n \t  __y = __x, __x = _S_left(__x);\n \telse\n \t  __x = _S_right(__x);\n-      return const_iterator(__y);\n+      return __y;\n     }\n \n   template<typename _Key, typename _Val, typename _KeyOfValue,\n \t   typename _Compare, typename _Alloc>\n     typename _Rb_tree<_Key, _Val, _KeyOfValue,\n-\t\t      _Compare, _Alloc>::iterator\n+\t\t      _Compare, _Alloc>::_Base_ptr\n     _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::\n-    _M_upper_bound(_Link_type __x, _Base_ptr __y,\n-\t\t   const _Key& __k)\n-    {\n-      while (__x != 0)\n-\tif (_M_impl._M_key_compare(__k, _S_key(__x)))\n-\t  __y = __x, __x = _S_left(__x);\n-\telse\n-\t  __x = _S_right(__x);\n-      return iterator(__y);\n-    }\n-\n-  template<typename _Key, typename _Val, typename _KeyOfValue,\n-\t   typename _Compare, typename _Alloc>\n-    typename _Rb_tree<_Key, _Val, _KeyOfValue,\n-\t\t      _Compare, _Alloc>::const_iterator\n-    _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::\n-    _M_upper_bound(_Const_Link_type __x, _Const_Base_ptr __y,\n+    _M_upper_bound(_Base_ptr __x, _Base_ptr __y,\n \t\t   const _Key& __k) const\n     {\n-      while (__x != 0)\n+      while (__x)\n \tif (_M_impl._M_key_compare(__k, _S_key(__x)))\n \t  __y = __x, __x = _S_left(__x);\n \telse\n \t  __x = _S_right(__x);\n-      return const_iterator(__y);\n+      return __y;\n     }\n \n   template<typename _Key, typename _Val, typename _KeyOfValue,\n@@ -2011,9 +2633,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n     _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::\n     equal_range(const _Key& __k)\n     {\n-      _Link_type __x = _M_begin();\n+      _Base_ptr __x = _M_begin();\n       _Base_ptr __y = _M_end();\n-      while (__x != 0)\n+      while (__x)\n \t{\n \t  if (_M_impl._M_key_compare(_S_key(__x), __k))\n \t    __x = _S_right(__x);\n@@ -2021,13 +2643,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n \t    __y = __x, __x = _S_left(__x);\n \t  else\n \t    {\n-\t      _Link_type __xu(__x);\n+\t      _Base_ptr __xu(__x);\n \t      _Base_ptr __yu(__y);\n \t      __y = __x, __x = _S_left(__x);\n \t      __xu = _S_right(__xu);\n-\t      return pair<iterator,\n-\t\t\t  iterator>(_M_lower_bound(__x, __y, __k),\n-\t\t\t\t    _M_upper_bound(__xu, __yu, __k));\n+\t      return make_pair(iterator(_M_lower_bound(__x, __y, __k)),\n+\t\t\t       iterator(_M_upper_bound(__xu, __yu, __k)));\n \t    }\n \t}\n       return pair<iterator, iterator>(iterator(__y),\n@@ -2043,9 +2664,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n     _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::\n     equal_range(const _Key& __k) const\n     {\n-      _Const_Link_type __x = _M_begin();\n-      _Const_Base_ptr __y = _M_end();\n-      while (__x != 0)\n+      _Base_ptr __x = _M_begin();\n+      _Base_ptr __y = _M_end();\n+      while (__x)\n \t{\n \t  if (_M_impl._M_key_compare(_S_key(__x), __k))\n \t    __x = _S_right(__x);\n@@ -2053,13 +2674,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n \t    __y = __x, __x = _S_left(__x);\n \t  else\n \t    {\n-\t      _Const_Link_type __xu(__x);\n-\t      _Const_Base_ptr __yu(__y);\n+\t      _Base_ptr __xu(__x);\n+\t      _Base_ptr __yu(__y);\n \t      __y = __x, __x = _S_left(__x);\n \t      __xu = _S_right(__xu);\n-\t      return pair<const_iterator,\n-\t\t\t  const_iterator>(_M_lower_bound(__x, __y, __k),\n-\t\t\t\t\t  _M_upper_bound(__xu, __yu, __k));\n+\t      return make_pair(const_iterator(_M_lower_bound(__x, __y, __k)),\n+\t\t\t       const_iterator(_M_upper_bound(__xu, __yu, __k)));\n \t    }\n \t}\n       return pair<const_iterator, const_iterator>(const_iterator(__y),\n@@ -2073,12 +2693,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n     swap(_Rb_tree& __t)\n     _GLIBCXX_NOEXCEPT_IF(__is_nothrow_swappable<_Compare>::value)\n     {\n-      if (_M_root() == 0)\n+      if (!_M_root())\n \t{\n-\t  if (__t._M_root() != 0)\n+\t  if (__t._M_root())\n \t    _M_impl._M_move_data(__t._M_impl);\n \t}\n-      else if (__t._M_root() == 0)\n+      else if (!__t._M_root())\n \t__t._M_impl._M_move_data(_M_impl);\n       else\n \t{\n@@ -2093,8 +2713,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n       // No need to swap header's color as it does not change.\n       std::swap(this->_M_impl._M_key_compare, __t._M_impl._M_key_compare);\n \n-      _Alloc_traits::_S_on_swap(_M_get_Node_allocator(),\n-\t\t\t\t__t._M_get_Node_allocator());\n+      _Node_alloc_traits::_S_on_swap(_M_get_Node_allocator(),\n+\t\t\t\t     __t._M_get_Node_allocator());\n     }\n \n   template<typename _Key, typename _Val, typename _KeyOfValue,\n@@ -2107,10 +2727,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n     _M_get_insert_unique_pos(const key_type& __k)\n     {\n       typedef pair<_Base_ptr, _Base_ptr> _Res;\n-      _Link_type __x = _M_begin();\n+      _Base_ptr __x = _M_begin();\n       _Base_ptr __y = _M_end();\n       bool __comp = true;\n-      while (__x != 0)\n+      while (__x)\n \t{\n \t  __y = __x;\n \t  __comp = _M_impl._M_key_compare(__k, _S_key(__x));\n@@ -2126,7 +2746,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n \t}\n       if (_M_impl._M_key_compare(_S_key(__j._M_node), __k))\n \treturn _Res(__x, __y);\n-      return _Res(__j._M_node, 0);\n+      return _Res(__j._M_node, _Base_ptr());\n     }\n \n   template<typename _Key, typename _Val, typename _KeyOfValue,\n@@ -2139,9 +2759,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n     _M_get_insert_equal_pos(const key_type& __k)\n     {\n       typedef pair<_Base_ptr, _Base_ptr> _Res;\n-      _Link_type __x = _M_begin();\n+      _Base_ptr __x = _M_begin();\n       _Base_ptr __y = _M_end();\n-      while (__x != 0)\n+      while (__x)\n \t{\n \t  __y = __x;\n \t  __x = _M_impl._M_key_compare(__k, _S_key(__x)) ?\n@@ -2209,44 +2829,43 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n     _M_get_insert_hint_unique_pos(const_iterator __position,\n \t\t\t\t  const key_type& __k)\n     {\n-      iterator __pos = __position._M_const_cast();\n       typedef pair<_Base_ptr, _Base_ptr> _Res;\n \n       // end()\n-      if (__pos._M_node == _M_end())\n+      if (__position._M_node == _M_end())\n \t{\n \t  if (size() > 0\n \t      && _M_impl._M_key_compare(_S_key(_M_rightmost()), __k))\n-\t    return _Res(0, _M_rightmost());\n+\t    return _Res(_Base_ptr(), _M_rightmost());\n \t  else\n \t    return _M_get_insert_unique_pos(__k);\n \t}\n-      else if (_M_impl._M_key_compare(__k, _S_key(__pos._M_node)))\n+      else if (_M_impl._M_key_compare(__k, _S_key(__position._M_node)))\n \t{\n \t  // First, try before...\n-\t  iterator __before = __pos;\n-\t  if (__pos._M_node == _M_leftmost()) // begin()\n+\t  iterator __before(__position._M_node);\n+\t  if (__position._M_node == _M_leftmost()) // begin()\n \t    return _Res(_M_leftmost(), _M_leftmost());\n \t  else if (_M_impl._M_key_compare(_S_key((--__before)._M_node), __k))\n \t    {\n-\t      if (_S_right(__before._M_node) == 0)\n-\t\treturn _Res(0, __before._M_node);\n+\t      if (!_S_right(__before._M_node))\n+\t\treturn _Res(_Base_ptr(), __before._M_node);\n \t      else\n-\t\treturn _Res(__pos._M_node, __pos._M_node);\n+\t\treturn _Res(__position._M_node, __position._M_node);\n \t    }\n \t  else\n \t    return _M_get_insert_unique_pos(__k);\n \t}\n-      else if (_M_impl._M_key_compare(_S_key(__pos._M_node), __k))\n+      else if (_M_impl._M_key_compare(_S_key(__position._M_node), __k))\n \t{\n \t  // ... then try after.\n-\t  iterator __after = __pos;\n-\t  if (__pos._M_node == _M_rightmost())\n-\t    return _Res(0, _M_rightmost());\n+\t  iterator __after(__position._M_node);\n+\t  if (__position._M_node == _M_rightmost())\n+\t    return _Res(_Base_ptr(), _M_rightmost());\n \t  else if (_M_impl._M_key_compare(__k, _S_key((++__after)._M_node)))\n \t    {\n-\t      if (_S_right(__pos._M_node) == 0)\n-\t\treturn _Res(0, __pos._M_node);\n+\t      if (!_S_right(__position._M_node))\n+\t\treturn _Res(_Base_ptr(), __position._M_node);\n \t      else\n \t\treturn _Res(__after._M_node, __after._M_node);\n \t    }\n@@ -2255,7 +2874,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n \t}\n       else\n \t// Equivalent keys.\n-\treturn _Res(__pos._M_node, 0);\n+\treturn _Res(__position._M_node, _Base_ptr());\n     }\n \n   template<typename _Key, typename _Val, typename _KeyOfValue,\n@@ -2294,30 +2913,29 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n     _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::\n     _M_get_insert_hint_equal_pos(const_iterator __position, const key_type& __k)\n     {\n-      iterator __pos = __position._M_const_cast();\n       typedef pair<_Base_ptr, _Base_ptr> _Res;\n \n       // end()\n-      if (__pos._M_node == _M_end())\n+      if (__position._M_node == _M_end())\n \t{\n \t  if (size() > 0\n \t      && !_M_impl._M_key_compare(__k, _S_key(_M_rightmost())))\n-\t    return _Res(0, _M_rightmost());\n+\t    return _Res(_Base_ptr(), _M_rightmost());\n \t  else\n \t    return _M_get_insert_equal_pos(__k);\n \t}\n-      else if (!_M_impl._M_key_compare(_S_key(__pos._M_node), __k))\n+      else if (!_M_impl._M_key_compare(_S_key(__position._M_node), __k))\n \t{\n \t  // First, try before...\n-\t  iterator __before = __pos;\n-\t  if (__pos._M_node == _M_leftmost()) // begin()\n+\t  iterator __before(__position._M_node);\n+\t  if (__position._M_node == _M_leftmost()) // begin()\n \t    return _Res(_M_leftmost(), _M_leftmost());\n \t  else if (!_M_impl._M_key_compare(__k, _S_key((--__before)._M_node)))\n \t    {\n-\t      if (_S_right(__before._M_node) == 0)\n-\t\treturn _Res(0, __before._M_node);\n+\t      if (!_S_right(__before._M_node))\n+\t\treturn _Res(_Base_ptr(), __before._M_node);\n \t      else\n-\t\treturn _Res(__pos._M_node, __pos._M_node);\n+\t\treturn _Res(__position._M_node, __position._M_node);\n \t    }\n \t  else\n \t    return _M_get_insert_equal_pos(__k);\n@@ -2325,18 +2943,18 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n       else\n \t{\n \t  // ... then try after.\n-\t  iterator __after = __pos;\n-\t  if (__pos._M_node == _M_rightmost())\n-\t    return _Res(0, _M_rightmost());\n+\t  iterator __after(__position._M_node);\n+\t  if (__position._M_node == _M_rightmost())\n+\t    return _Res(_Base_ptr(), _M_rightmost());\n \t  else if (!_M_impl._M_key_compare(_S_key((++__after)._M_node), __k))\n \t    {\n-\t      if (_S_right(__pos._M_node) == 0)\n-\t\treturn _Res(0, __pos._M_node);\n+\t      if (!_S_right(__position._M_node))\n+\t\treturn _Res(_Base_ptr(), __position._M_node);\n \t      else\n \t\treturn _Res(__after._M_node, __after._M_node);\n \t    }\n \t  else\n-\t    return _Res(0, 0);\n+\t    return _Res(_Base_ptr(), _Base_ptr());\n \t}\n     }\n \n@@ -2373,46 +2991,48 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n \t   typename _Compare, typename _Alloc>\n     auto\n     _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::\n-    _M_insert_node(_Base_ptr __x, _Base_ptr __p, _Link_type __z)\n+    _M_insert_node(_Base_ptr __x, _Base_ptr __p, _Node_ptr __z)\n     -> iterator\n     {\n-      bool __insert_left = (__x != 0 || __p == _M_end()\n+      bool __insert_left = (__x || __p == _M_end()\n \t\t\t    || _M_impl._M_key_compare(_S_key(__z),\n \t\t\t\t\t\t      _S_key(__p)));\n \n-      _Rb_tree_insert_and_rebalance(__insert_left, __z, __p,\n-\t\t\t\t    this->_M_impl._M_header);\n+      _Base_ptr __base_z = __z->_M_base_ptr();\n+      _Node_traits::_S_insert_and_rebalance\n+\t(__insert_left, __base_z, __p, this->_M_impl._M_header);\n       ++_M_impl._M_node_count;\n-      return iterator(__z);\n+      return iterator(__base_z);\n     }\n \n   template<typename _Key, typename _Val, typename _KeyOfValue,\n \t   typename _Compare, typename _Alloc>\n     auto\n     _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::\n-    _M_insert_lower_node(_Base_ptr __p, _Link_type __z)\n+    _M_insert_lower_node(_Base_ptr __p, _Node_ptr __z)\n     -> iterator\n     {\n       bool __insert_left = (__p == _M_end()\n \t\t\t    || !_M_impl._M_key_compare(_S_key(__p),\n \t\t\t\t\t\t       _S_key(__z)));\n \n-      _Rb_tree_insert_and_rebalance(__insert_left, __z, __p,\n-\t\t\t\t    this->_M_impl._M_header);\n+      _Base_ptr __base_z = __z->_M_base_ptr();\n+      _Node_traits::_S_insert_and_rebalance\n+\t(__insert_left, __base_z, __p, this->_M_impl._M_header);\n       ++_M_impl._M_node_count;\n-      return iterator(__z);\n+      return iterator(__base_z);\n     }\n \n   template<typename _Key, typename _Val, typename _KeyOfValue,\n \t   typename _Compare, typename _Alloc>\n     auto\n     _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::\n-    _M_insert_equal_lower_node(_Link_type __z)\n+    _M_insert_equal_lower_node(_Node_ptr __z)\n     -> iterator\n     {\n-      _Link_type __x = _M_begin();\n+      _Base_ptr __x = _M_begin();\n       _Base_ptr __y = _M_end();\n-      while (__x != 0)\n+      while (__x)\n \t{\n \t  __y = __x;\n \t  __x = !_M_impl._M_key_compare(_S_key(__x), _S_key(__z)) ?\n@@ -2487,11 +3107,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n     _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::\n     _M_erase_aux(const_iterator __position)\n     {\n-      _Link_type __y =\n-\tstatic_cast<_Link_type>(_Rb_tree_rebalance_for_erase\n-\t\t\t\t(const_cast<_Base_ptr>(__position._M_node),\n-\t\t\t\t this->_M_impl._M_header));\n-      _M_drop_node(__y);\n+      _Base_ptr __y = _Node_traits::_S_rebalance_for_erase\n+\t(__position._M_node, this->_M_impl._M_header);\n+      _M_drop_node(static_cast<_Node&>(*__y)._M_node_ptr());\n       --_M_impl._M_node_count;\n     }\n \n@@ -2527,7 +3145,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n     _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::\n     find(const _Key& __k)\n     {\n-      iterator __j = _M_lower_bound(_M_begin(), _M_end(), __k);\n+      iterator __j(_M_lower_bound(_M_begin(), _M_end(), __k));\n       return (__j == end()\n \t      || _M_impl._M_key_compare(__k,\n \t\t\t\t\t_S_key(__j._M_node))) ? end() : __j;\n@@ -2540,7 +3158,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n     _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::\n     find(const _Key& __k) const\n     {\n-      const_iterator __j = _M_lower_bound(_M_begin(), _M_end(), __k);\n+      const_iterator __j(_M_lower_bound(_M_begin(), _M_end(), __k));\n       return (__j == end()\n \t      || _M_impl._M_key_compare(__k,\n \t\t\t\t\t_S_key(__j._M_node))) ? end() : __j;\n@@ -2574,9 +3192,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n       unsigned int __len = _Rb_tree_black_count(_M_leftmost(), _M_root());\n       for (const_iterator __it = begin(); __it != end(); ++__it)\n \t{\n-\t  _Const_Link_type __x = static_cast<_Const_Link_type>(__it._M_node);\n-\t  _Const_Link_type __L = _S_left(__x);\n-\t  _Const_Link_type __R = _S_right(__x);\n+\t  _Base_ptr __x = __it._M_node;\n+\t  _Base_ptr __L = _S_left(__x);\n+\t  _Base_ptr __R = _S_right(__x);\n \n \t  if (__x->_M_color == _S_red)\n \t    if ((__L && __L->_M_color == _S_red)\n@@ -2592,9 +3210,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n \t    return false;\n \t}\n \n-      if (_M_leftmost() != _Rb_tree_node_base::_S_minimum(_M_root()))\n+      if (_M_leftmost() != _Node_base::_S_minimum(_M_root()))\n \treturn false;\n-      if (_M_rightmost() != _Rb_tree_node_base::_S_maximum(_M_root()))\n+      if (_M_rightmost() != _Node_base::_S_maximum(_M_root()))\n \treturn false;\n       return true;\n     }\ndiff --git a/libstdc++-v3/testsuite/23_containers/map/allocator/ext_ptr.cc b/libstdc++-v3/testsuite/23_containers/map/allocator/ext_ptr.cc\nnew file mode 100644\nindex 000000000000..3d83738f86b3\n--- /dev/null\n+++ b/libstdc++-v3/testsuite/23_containers/map/allocator/ext_ptr.cc\n@@ -0,0 +1,37 @@\n+// { dg-do run { target c++11 } }\n+\n+#include <map>\n+#include <memory>\n+#include <testsuite_hooks.h>\n+#include <testsuite_allocator.h>\n+\n+struct T { int i; };\n+\n+bool operator<(const T& l, const T& r)\n+{ return l.i < r.i; }\n+\n+struct L : std::less<T>\n+{ };\n+\n+using __gnu_test::CustomPointerAlloc;\n+\n+template class std::map<T, int, L,\n+\t\t\tCustomPointerAlloc<std::pair<const T, int>>>;\n+\n+void test01()\n+{\n+  typedef CustomPointerAlloc<std::pair<const T, int>> alloc_type;\n+  typedef std::map<T, int, L, alloc_type> test_type;\n+  test_type v;\n+  v.insert({ T(), 0 });\n+  VERIFY( v.begin()->second == 0 );\n+  VERIFY( ++v.begin() == v.end() );\n+  v.insert({ T { 1 }, 1 });\n+  VERIFY( v.size() == 2 );\n+  VERIFY( v.find(T()) != v.end() );\n+}\n+\n+int main()\n+{\n+  test01();\n+}\ndiff --git a/libstdc++-v3/testsuite/23_containers/multimap/allocator/ext_ptr.cc b/libstdc++-v3/testsuite/23_containers/multimap/allocator/ext_ptr.cc\nnew file mode 100644\nindex 000000000000..41689ef43b7e\n--- /dev/null\n+++ b/libstdc++-v3/testsuite/23_containers/multimap/allocator/ext_ptr.cc\n@@ -0,0 +1,33 @@\n+// { dg-do run { target c++11 } }\n+\n+#include <map>\n+#include <memory>\n+#include <testsuite_hooks.h>\n+#include <testsuite_allocator.h>\n+\n+struct T { int i; };\n+\n+bool operator<(const T& l, const T& r)\n+{ return l.i < r.i; }\n+\n+struct L : std::less<T>\n+{ };\n+\n+using __gnu_test::CustomPointerAlloc;\n+\n+template class std::multimap<T, int, L,\n+\t\t\tCustomPointerAlloc<std::pair<const T, int>>>;\n+\n+void test01()\n+{\n+  typedef CustomPointerAlloc<std::pair<const T, int>> alloc_type;\n+  typedef std::multimap<T, int, L, alloc_type> test_type;\n+  test_type v;\n+  v.insert({ T(), 0 });\n+  VERIFY( ++v.begin() == v.end() );\n+}\n+\n+int main()\n+{\n+  test01();\n+}\ndiff --git a/libstdc++-v3/testsuite/23_containers/multiset/allocator/ext_ptr.cc b/libstdc++-v3/testsuite/23_containers/multiset/allocator/ext_ptr.cc\nnew file mode 100644\nindex 000000000000..589e6b0a617e\n--- /dev/null\n+++ b/libstdc++-v3/testsuite/23_containers/multiset/allocator/ext_ptr.cc\n@@ -0,0 +1,32 @@\n+// { dg-do run { target c++11 } }\n+\n+#include <set>\n+#include <memory>\n+#include <testsuite_hooks.h>\n+#include <testsuite_allocator.h>\n+\n+struct T { int i; };\n+\n+bool operator<(const T& l, const T& r)\n+{ return l.i < r.i; }\n+\n+struct L : std::less<T>\n+{ };\n+\n+using __gnu_test::CustomPointerAlloc;\n+\n+template class std::multiset<T, L, CustomPointerAlloc<T>>;\n+\n+void test01()\n+{\n+  typedef CustomPointerAlloc<T> alloc_type;\n+  typedef std::multiset<T, L, alloc_type> test_type;\n+  test_type v;\n+  v.insert(T());\n+  VERIFY( ++v.begin() == v.end() );\n+}\n+\n+int main()\n+{\n+  test01();\n+}\ndiff --git a/libstdc++-v3/testsuite/23_containers/set/allocator/ext_ptr.cc b/libstdc++-v3/testsuite/23_containers/set/allocator/ext_ptr.cc\nnew file mode 100644\nindex 000000000000..bbcf32b20be3\n--- /dev/null\n+++ b/libstdc++-v3/testsuite/23_containers/set/allocator/ext_ptr.cc\n@@ -0,0 +1,32 @@\n+// { dg-do run { target c++11 } }\n+\n+#include <set>\n+#include <memory>\n+#include <testsuite_hooks.h>\n+#include <testsuite_allocator.h>\n+\n+struct T { int i; };\n+\n+bool operator<(const T& l, const T& r)\n+{ return l.i < r.i; }\n+\n+struct L : std::less<T>\n+{ };\n+\n+using __gnu_test::CustomPointerAlloc;\n+\n+template class std::set<T, L, CustomPointerAlloc<T>>;\n+\n+void test01()\n+{\n+  typedef CustomPointerAlloc<T> alloc_type;\n+  typedef std::set<T, L, alloc_type> test_type;\n+  test_type v;\n+  v.insert(T());\n+  VERIFY( ++v.begin() == v.end() );\n+}\n+\n+int main()\n+{\n+  test01();\n+}\ndiff --git a/libstdc++-v3/testsuite/23_containers/set/requirements/explicit_instantiation/alloc_ptr.cc b/libstdc++-v3/testsuite/23_containers/set/requirements/explicit_instantiation/alloc_ptr.cc\nnew file mode 100644\nindex 000000000000..60b583a9b2be\n--- /dev/null\n+++ b/libstdc++-v3/testsuite/23_containers/set/requirements/explicit_instantiation/alloc_ptr.cc\n@@ -0,0 +1,86 @@\n+// { dg-do compile { target c++11 } }\n+\n+#include <set>\n+#include <testsuite_allocator.h>\n+\n+// An allocator that uses __gnu_cxx::_Pointer_adapter as its pointer type.\n+template class std::set<int, std::less<int>,\n+\t\t\t__gnu_test::CustomPointerAlloc<int>>;\n+\n+// Unlike __gnu_cxx::_Pointer_adapter, this fancy pointer supports neither\n+// implicit nor explicit conversions from raw pointers. The constructor from\n+// a raw pointer is explicit and requires a second parameter. The only way for\n+// containers to construct one of these pointers is pointer_traits::pointer_to.\n+template<typename T>\n+struct Pointer : __gnu_test::PointerBase<Pointer<T>, T>\n+{\n+  using Base = __gnu_test::PointerBase<Pointer<T>, T>;\n+\n+  Pointer() = default;\n+  Pointer(std::nullptr_t) : Base() { }\n+  explicit Pointer(T* p, int) : Base(p) { }\n+\n+  // Allow conversions to const_pointer and to void_pointer\n+  template<typename U, typename = typename std::enable_if<\n+    (!std::is_const<U>::value && std::is_same<T, const U>::value)\n+    || (std::is_void<T>::value && std::is_convertible<U*, T*>::value)\n+    >::type>\n+    Pointer(const Pointer<U>& p) : Base(p.operator->()) { }\n+\n+  template<typename U>\n+    static typename std::enable_if<std::is_same<U, T>::value, Pointer>::type\n+    pointer_to(U& t)\n+    { return Pointer(std::addressof(t), 1); }\n+};\n+\n+// A minimal allocator that uses Pointer as its pointer type.\n+template<typename T>\n+struct Allocator\n+{\n+  using value_type = T;\n+  using pointer = Pointer<T>;\n+\n+  Allocator() = default;\n+  template<typename U>\n+    Allocator(const Allocator<U>&) { }\n+\n+  pointer allocate(std::size_t n)\n+  { return pointer(std::allocator<T>().allocate(n), 1); }\n+\n+  void deallocate(pointer p, std::size_t n)\n+  {\n+    std::allocator<T>().deallocate(p.operator->(), n);\n+  }\n+\n+  bool operator==(const Allocator&) const { return true; }\n+  bool operator!=(const Allocator&) const { return false; }\n+};\n+\n+template class std::set<int, std::less<int>, Allocator<int>>;\n+\n+#include <testsuite_iterators.h>\n+\n+void\n+test_template_members(__gnu_test::input_container<short>& c)\n+{\n+  // Use member functions that are not included in explicit instantiations.\n+  std::set<int, std::less<int>, Allocator<int>> s(c.begin(), c.end());\n+  s.emplace(1);\n+  s.emplace_hint(s.begin(), 1);\n+  s.insert(c.begin(), c.end());\n+\n+  std::set<int, std::greater<int>, Allocator<int>> s1;\n+  s.merge(s1);\n+  std::multiset<int, std::greater<int>, Allocator<int>> m1;\n+  s.merge(m1);\n+\n+#ifdef __glibcxx_ranges_to_container\n+  short arr[2];\n+  __gnu_test::test_input_range<short> r(arr);\n+  std::set<int, std::less<int>, Allocator<int>> s2(std::from_range, r);\n+  s2.assign_range(r);\n+  s2.prepend_range(r);\n+  s2.append_range(r);\n+  s2.insert_range(s2.begin(), r);\n+#endif\n+}\ndiff --git a/libstdc++-v3/testsuite/23_containers/set/requirements/explicit_instantiation/alloc_ptr_ignored.cc b/libstdc++-v3/testsuite/23_containers/set/requirements/explicit_instantiation/alloc_ptr_ignored.cc\nnew file mode 100644\nindex 000000000000..fa06cf8f3a2f\n--- /dev/null\n+++ b/libstdc++-v3/testsuite/23_containers/set/requirements/explicit_instantiation/alloc_ptr_ignored.cc\n@@ -0,0 +1,4 @@\n+// { dg-options \"-D_GLIBCXX_USE_ALLOC_PTR_FOR_RB_TREE=0\" }\n+// { dg-do compile { target c++11 } }\n+\n+#include \"alloc_ptr.cc\"\n",
    "prefixes": [
        "v1",
        "1/1"
    ]
}