re PR libstdc++/52942 (using std::ref with a std::unordered_map fails to compile)

2012-04-12  Paolo Carlini  <paolo.carlini@oracle.com>

	PR libstdc++/52942
	* include/bits/stl_function.h (_Identity, _Select1st, _Select2nd):
	In C++11 mode do not derive from std::unary_function.
	* include/ext/functional (identity, select1st, select2nd): Adjust.
	* testsuite/23_containers/unordered_map/requirements/52942.cc: New.
	* testsuite/23_containers/unordered_set/requirements/52942.cc: Likewise.

From-SVN: r186375

5 files changed, 121 insertions, 10 deletions

diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index 80321a0..b8cea52 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,3 +1,12 @@
+2012-04-12  Paolo Carlini  <paolo.carlini@oracle.com>
+
+	PR libstdc++/52942
+	* include/bits/stl_function.h (_Identity, _Select1st, _Select2nd):
+	In C++11 mode do not derive from std::unary_function.
+	* include/ext/functional (identity, select1st, select2nd): Adjust.
+	* testsuite/23_containers/unordered_map/requirements/52942.cc: New.
+	* testsuite/23_containers/unordered_set/requirements/52942.cc: Likewise.
+
 2012-04-11  Jonathan Wakely  <jwakely.gcc@gmail.com>
 
 	PR libstdc++/52924
diff --git a/libstdc++-v3/include/bits/stl_function.h b/libstdc++-v3/include/bits/stl_function.h
index 88655fc..33d5e70 100644
--- a/libstdc++-v3/include/bits/stl_function.h
+++ b/libstdc++-v3/include/bits/stl_function.h
@@ -1,6 +1,7 @@
 // Functor implementations -*- C++ -*-
 
-// Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2009, 2010, 2011
+// Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2009, 2010,
+// 2011, 2012
 // Free Software Foundation, Inc.
 //
 // This file is part of the GNU ISO C++ Library.  This library is free
@@ -471,7 +472,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
   /** @}  */
 
   template<typename _Tp>
-    struct _Identity : public unary_function<_Tp,_Tp>
+    struct _Identity
+#ifndef __GXX_EXPERIMENTAL_CXX0X__
+    // unary_function itself is deprecated in C++11 and deriving from
+    // it can even be a nuisance (see PR 52942).
+    : public unary_function<_Tp,_Tp>
+#endif
     {
       _Tp&
       operator()(_Tp& __x) const
@@ -483,8 +489,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     };
 
   template<typename _Pair>
-    struct _Select1st : public unary_function<_Pair,
-					      typename _Pair::first_type>
+    struct _Select1st
+#ifndef __GXX_EXPERIMENTAL_CXX0X__
+    : public unary_function<_Pair, typename _Pair::first_type>
+#endif
     {
       typename _Pair::first_type&
       operator()(_Pair& __x) const
@@ -508,8 +516,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     };
 
   template<typename _Pair>
-    struct _Select2nd : public unary_function<_Pair,
-					      typename _Pair::second_type>
+    struct _Select2nd
+#ifndef __GXX_EXPERIMENTAL_CXX0X__
+    : public unary_function<_Pair, typename _Pair::second_type>
+#endif
     {
       typename _Pair::second_type&
       operator()(_Pair& __x) const
diff --git a/libstdc++-v3/include/ext/functional b/libstdc++-v3/include/ext/functional
index 85b944b..f8402c1 100644
--- a/libstdc++-v3/include/ext/functional
+++ b/libstdc++-v3/include/ext/functional
@@ -1,6 +1,6 @@
 // Functional extensions -*- C++ -*-
 
-// Copyright (C) 2002, 2003, 2004, 2005, 2006, 2007, 2009, 2010
+// Copyright (C) 2002, 2003, 2004, 2005, 2006, 2007, 2009, 2010, 2012
 // Free Software Foundation, Inc.
 //
 // This file is part of the GNU ISO C++ Library.  This library is free
@@ -183,7 +183,13 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
    *  @addtogroup SGIextensions
    */
   template <class _Tp>
-    struct identity : public std::_Identity<_Tp> {};
+    struct identity
+#ifdef __GXX_EXPERIMENTAL_CXX0X__
+    : public std::unary_function<_Tp,_Tp>,
+      public std::_Identity<_Tp> {};
+#else
+    : public std::_Identity<_Tp> {};
+#endif
 
   /** @c select1st and @c select2nd are extensions provided by SGI.  Their
    *  @c operator()s
@@ -197,11 +203,23 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
    */
   /// An \link SGIextensions SGI extension \endlink.
   template <class _Pair>
-    struct select1st : public std::_Select1st<_Pair> {};
+    struct select1st
+#ifdef __GXX_EXPERIMENTAL_CXX0X__
+    : public std::unary_function<_Pair, typename _Pair::first_type>,
+      public std::_Select1st<_Pair> {};
+#else
+    : public std::_Select1st<_Pair> {};
+#endif
 
   /// An \link SGIextensions SGI extension \endlink.
   template <class _Pair>
-    struct select2nd : public std::_Select2nd<_Pair> {};
+    struct select2nd
+#ifdef __GXX_EXPERIMENTAL_CXX0X__
+    : public std::unary_function<_Pair, typename _Pair::second_type>,
+      public std::_Select2nd<_Pair> {};
+#else
+    : public std::_Select2nd<_Pair> {};
+#endif
   /** @}  */
 
   // extension documented next
diff --git a/libstdc++-v3/testsuite/23_containers/unordered_map/requirements/52942.cc b/libstdc++-v3/testsuite/23_containers/unordered_map/requirements/52942.cc
new file mode 100644
index 0000000..bf05fab
--- /dev/null
+++ b/libstdc++-v3/testsuite/23_containers/unordered_map/requirements/52942.cc
@@ -0,0 +1,37 @@
+// { dg-do compile }
+// { dg-options "-std=gnu++11" }
+
+// Copyright (C) 2012 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 Pred 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/>.
+
+#include <unordered_map>
+#include <functional>
+
+struct TFoo {};
+
+struct TFoo_hash
+{
+  std::size_t operator()(const TFoo &) const { return 0; }
+};
+
+void f1(std::unordered_map<TFoo, int, TFoo_hash> &) {}
+
+void f2()
+{
+  std::unordered_map<TFoo, int, TFoo_hash> map1;
+  std::bind(f1, std::ref(map1));
+}
diff --git a/libstdc++-v3/testsuite/23_containers/unordered_set/requirements/52942.cc b/libstdc++-v3/testsuite/23_containers/unordered_set/requirements/52942.cc
new file mode 100644
index 0000000..067e57a
--- /dev/null
+++ b/libstdc++-v3/testsuite/23_containers/unordered_set/requirements/52942.cc
@@ -0,0 +1,37 @@
+// { dg-do compile }
+// { dg-options "-std=gnu++11" }
+
+// Copyright (C) 2012 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 Pred 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/>.
+
+#include <unordered_set>
+#include <functional>
+
+struct TFoo {};
+
+struct TFoo_hash
+{
+  std::size_t operator()(const TFoo &) const { return 0; }
+};
+
+void f1(std::unordered_set<TFoo, TFoo_hash> &) {}
+
+void f2()
+{
+  std::unordered_set<TFoo, TFoo_hash> set1;
+  std::bind(f1, std::ref(set1));
+}