[PATCH] PR libstdc++/83226 avoid forming pointer-to-reference type

[Jonathan Wakely]

We need to strip references from the key_type and mapped_type before
forming pointers to them.

        PR libstdc++/83226
        * include/bits/node_handle.h (_Node_handle::__pointer): Avoid forming
        pointer-to-reference types.
        * testsuite/23_containers/map/modifiers/insert/83226.cc: New test.

Tested powerpc64le-linux, committed to trunk. Backport to gcc-7 to
follow.


commit 9d17e1a6bc20ac7d718930b00dc9858295bc6a09
Author: Jonathan Wakely <jwak...@redhat.com>
Date:   Thu Nov 30 13:00:05 2017 +0000

    PR libstdc++/83226 avoid forming pointer-to-reference type
    
            PR libstdc++/83226
            * include/bits/node_handle.h (_Node_handle::__pointer): Avoid 
forming
            pointer-to-reference types.
            * testsuite/23_containers/map/modifiers/insert/83226.cc: New test.

diff --git a/libstdc++-v3/include/bits/node_handle.h 
b/libstdc++-v3/include/bits/node_handle.h
index 0d8dbeb4110..7f109ada6f1 100644
--- a/libstdc++-v3/include/bits/node_handle.h
+++ b/libstdc++-v3/include/bits/node_handle.h
@@ -199,7 +199,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       }
 
       template<typename _Tp>
-       using __pointer = __ptr_rebind<typename _AllocTraits::pointer, _Tp>;
+       using __pointer
+         = __ptr_rebind<typename _AllocTraits::pointer,
+                        remove_reference_t<_Tp>>;
 
       __pointer<_Key>                          _M_pkey = nullptr;
       __pointer<typename _Value::second_type>  _M_pmapped = nullptr;
diff --git a/libstdc++-v3/testsuite/23_containers/map/modifiers/insert/83226.cc 
b/libstdc++-v3/testsuite/23_containers/map/modifiers/insert/83226.cc
new file mode 100644
index 00000000000..07afa5cbd87
--- /dev/null
+++ b/libstdc++-v3/testsuite/23_containers/map/modifiers/insert/83226.cc
@@ -0,0 +1,30 @@
+// Copyright (C) 2017 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+// { dg-options "-std=gnu++17" }
+// { dg-do compile { target c++17 } }
+
+#include <map>
+
+void
+test01()
+{
+  int i = 0;
+  std::map<int, int&> m;
+  std::pair<const int, int&> p{1, i};
+  m.insert(p); // PR libstdc++/83226
+}