Re: Fix std::pair std::is_copy_assignable behavior

[François Dumont <frs dot dumont at gmail dot com>]

Hi

    Here is an other proposal to fix std::is_copy_assignable<std::pair<>>.

    This is not perfect because I have adapted it to current compiler 
behavior but it is still better than current behavior and enough to 
commit the unordered C++11 allocator adaptation afterward. It will give 
me more time to work on the Standard modification proposal to avoid the 
partial template specialization used for the moment.

    Thanks to current resolution of DR 1402 we can already define the 
move assignment operator as default, if deleted the template move 
assignment operator will be considered and potentially used instead.

2013-04-17  François Dumont <fdumont@gcc.gnu.org>

    * include/bits/stl_pair.h (operator=(const pair&)): Add noexcept
    qualification.
    (operator=(pair&&)): Use default implementation.
    (template<> operator=(const pair&)): Add noexcept
    qualification. Enable if is_assignable<T&, const U&> true for both
    parameter types.
    (template<> operator=(pair<>&&)): Add noexcept
    qualification. Enable if is_assignable<T&, U&&> true for both
    parameter types.
    (std::is_copy_assignable<>, std::is_move_assignable<>): Add
    partial specialization.
    * testsuite/20_util/pair/is_move_assignable.cc: New.
    * testsuite/20_util/pair/is_copy_assignable.cc: Likewise.
    * testsuite/20_util/pair/is_assignable.cc: Likewise.
    * testsuite/20_util/pair/is_nothrow_move_assignable.cc: Likewise.
    * testsuite/20_util/pair/assign_neg.cc: Likewise.
    * testsuite/20_util/pair/is_nothrow_copy_assignable.cc: Likewise.
    * testsuite/20_util/pair/assign.cc: Likewise.

Tested under Linux x86_64.

Ok to commit ?

François

Index: include/bits/stl_pair.h
===================================================================
--- include/bits/stl_pair.h	(revision 197829)
+++ include/bits/stl_pair.h	(working copy)
@@ -156,6 +156,8 @@
 
       pair&
       operator=(const pair& __p)
+      noexcept(__and_<is_nothrow_copy_assignable<_T1>,
+		      is_nothrow_copy_assignable<_T2>>::value)
       {
 	first = __p.first;
 	second = __p.second;
@@ -163,18 +165,15 @@
       }
 
       pair&
-      operator=(pair&& __p)
-      noexcept(__and_<is_nothrow_move_assignable<_T1>,
-	              is_nothrow_move_assignable<_T2>>::value)
-      {
-	first = std::forward<first_type>(__p.first);
-	second = std::forward<second_type>(__p.second);
-	return *this;
-      }
+      operator=(pair&&) = default;
 
       template<class _U1, class _U2>
-	pair&
+	typename enable_if<__and_<is_assignable<_T1&, const _U1&>,
+				  is_assignable<_T2&, const _U2&>>::value,
+			   pair&>::type
 	operator=(const pair<_U1, _U2>& __p)
+	noexcept(__and_<is_nothrow_assignable<_T1&, const _U1&>,
+			is_nothrow_assignable<_T2&, const _U2&>>::value)
 	{
 	  first = __p.first;
 	  second = __p.second;
@@ -182,8 +181,12 @@
 	}
 
       template<class _U1, class _U2>
-	pair&
+      	typename enable_if<__and_<is_assignable<_T1&, _U1&&>,
+      				  is_assignable<_T2&, _U2&&>>::value,
+      			   pair&>::type
 	operator=(pair<_U1, _U2>&& __p)
+	noexcept(__and_<is_nothrow_assignable<_T1&, _U1&&>,
+			is_nothrow_assignable<_T2&, _U2&&>>::value)
 	{
 	  first = std::forward<_U1>(__p.first);
 	  second = std::forward<_U2>(__p.second);
@@ -287,6 +290,19 @@
     { return pair<_T1, _T2>(__x, __y); }
 #endif
 
+#if __cplusplus >= 201103L
+  template<class _T1, class _T2>
+    struct is_copy_assignable<std::pair<_T1, _T2>>
+      : public __and_<std::is_copy_assignable<_T1>,
+		      std::is_copy_assignable<_T2>>::type
+    { };
+
+  template<class _T1, class _T2>
+    struct is_move_assignable<std::pair<_T1, _T2>>
+      : public __and_<std::is_move_assignable<_T1>,
+		      std::is_move_assignable<_T2>>::type
+    { };
+#endif
   /// @}
 
 _GLIBCXX_END_NAMESPACE_VERSION
Index: testsuite/20_util/pair/is_assignable.cc
===================================================================
--- testsuite/20_util/pair/is_assignable.cc	(revision 0)
+++ testsuite/20_util/pair/is_assignable.cc	(revision 0)
@@ -0,0 +1,48 @@
+// { dg-do compile }
+// { dg-options "-std=c++11" }
+
+// Copyright (C) 2013 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/>.
+
+#include <type_traits>
+#include <utility>
+
+struct T1
+{
+};
+
+struct T2
+{
+  T2&
+  operator=(const T1&);
+};
+
+typedef std::pair<int, int>						pt1;
+typedef std::pair<short, short>						pt2;
+typedef std::pair<int, double> pt3;
+typedef std::pair<int, T1> pt4;
+typedef std::pair<int, T2> pt5;
+
+static_assert(std::is_assignable<pt1, pt2>::value, "Error");
+static_assert(std::is_assignable<pt2, pt1>::value, "Error");
+static_assert(std::is_assignable<pt1, pt3>::value, "Error");
+static_assert(!std::is_assignable<pt4, pt1>::value, "Error");
+static_assert(!std::is_assignable<pt1, pt4>::value, "Error");
+static_assert(std::is_assignable<pt5, pt4>::value, "Error");
+static_assert(!std::is_assignable<pt4, pt5>::value, "Error");
+
+
Index: testsuite/20_util/pair/is_nothrow_move_assignable.cc
===================================================================
--- testsuite/20_util/pair/is_nothrow_move_assignable.cc	(revision 0)
+++ testsuite/20_util/pair/is_nothrow_move_assignable.cc	(revision 0)
@@ -0,0 +1,57 @@
+// { dg-do compile }
+// { dg-options "-std=c++11" }
+
+// Copyright (C) 2013 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/>.
+
+#include <type_traits>
+#include <utility>
+#include <testsuite_tr1.h>
+
+using namespace __gnu_test;
+
+typedef std::pair<int, int>						pt1;
+typedef std::pair<int, double>						pt2;
+typedef std::pair<NoexceptCopyAssignClass, NoexceptCopyAssignClass>	pt3;
+typedef std::pair<ExceptCopyAssignClass, ExceptCopyAssignClass>		pt4;
+typedef std::pair<ExceptCopyAssignClass, double>			pt5;
+typedef std::pair<NoexceptCopyAssignClass, ExceptCopyAssignClass>	pt6;
+typedef std::pair<const int, int>					pt7;
+typedef std::pair<int, const int>					pt8;
+typedef std::pair<NoexceptMoveAssignClass, NoexceptMoveAssignClass>	pt9;
+typedef std::pair<ExceptMoveAssignClass, ExceptMoveAssignClass>		pt10;
+typedef std::pair<ExceptMoveAssignClass, NoexceptMoveAssignClass>	pt11;
+typedef std::pair<NoexceptMoveAssignClass, ExceptMoveAssignClass>	pt12;
+typedef std::pair<int, int&>						pt13;
+typedef std::pair<int&, int&>						pt14;
+typedef std::pair<int, const int&>					pt15;
+
+static_assert(std::is_nothrow_move_assignable<pt1>::value, "Error");
+static_assert(std::is_nothrow_move_assignable<pt2>::value, "Error");
+static_assert(std::is_nothrow_move_assignable<pt3>::value, "Error");
+static_assert(!std::is_nothrow_move_assignable<pt4>::value, "Error");
+static_assert(!std::is_nothrow_move_assignable<pt5>::value, "Error");
+static_assert(!std::is_nothrow_move_assignable<pt6>::value, "Error");
+static_assert(!std::is_nothrow_move_assignable<pt7>::value, "Error");
+static_assert(!std::is_nothrow_move_assignable<pt8>::value, "Error");
+static_assert(std::is_nothrow_move_assignable<pt9>::value, "Error");
+static_assert(!std::is_nothrow_move_assignable<pt10>::value, "Error");
+static_assert(!std::is_nothrow_move_assignable<pt11>::value, "Error");
+static_assert(!std::is_nothrow_move_assignable<pt12>::value, "Error");
+static_assert(std::is_nothrow_move_assignable<pt13>::value, "Error");
+static_assert(std::is_nothrow_move_assignable<pt14>::value, "Error");
+static_assert(!std::is_nothrow_move_assignable<pt15>::value, "Error");
Index: testsuite/20_util/pair/assign_neg.cc
===================================================================
--- testsuite/20_util/pair/assign_neg.cc	(revision 0)
+++ testsuite/20_util/pair/assign_neg.cc	(revision 0)
@@ -0,0 +1,30 @@
+// { dg-do compile }
+// { dg-options "-std=c++11" }
+
+// Copyright (C) 2013 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/>.
+
+#include <utility>
+
+void test01()
+{
+  std::pair<const int, int> p;
+  p = p;
+  p = std::move(p);
+}
+
+// { dg-error "assignment of read-only member" "" { target *-*-* } 162 }
Index: testsuite/20_util/pair/is_nothrow_copy_assignable.cc
===================================================================
--- testsuite/20_util/pair/is_nothrow_copy_assignable.cc	(revision 0)
+++ testsuite/20_util/pair/is_nothrow_copy_assignable.cc	(revision 0)
@@ -0,0 +1,53 @@
+// { dg-do compile }
+// { dg-options "-std=c++11" }
+
+// Copyright (C) 2013 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/>.
+
+#include <type_traits>
+#include <utility>
+#include <testsuite_tr1.h>
+
+using namespace __gnu_test;
+
+typedef std::pair<int, int>						pt1;
+typedef std::pair<int, double>						pt2;
+typedef std::pair<const int, int>					pt3;
+typedef std::pair<int, const int>					pt4;
+typedef std::pair<int, const int>&					pt5;
+typedef std::pair<NoexceptCopyAssignClass, NoexceptCopyAssignClass>	pt6;
+typedef std::pair<ExceptCopyAssignClass, ExceptCopyAssignClass>		pt7;
+typedef std::pair<ExceptCopyAssignClass, double>			pt8;
+typedef std::pair<NoexceptCopyAssignClass, ExceptCopyAssignClass>	pt9;
+typedef std::pair<int, DeletedCopyAssignClass>				pt10;
+typedef std::pair<int, int&>						pt11;
+typedef std::pair<int&, int&>						pt12;
+typedef std::pair<int, const int&>					pt13;
+
+static_assert(std::is_nothrow_copy_assignable<pt1>::value, "Error");
+static_assert(std::is_nothrow_copy_assignable<pt2>::value, "Error");
+static_assert(!std::is_nothrow_copy_assignable<pt3>::value, "Error");
+static_assert(!std::is_nothrow_copy_assignable<pt4>::value, "Error");
+static_assert(!std::is_nothrow_copy_assignable<pt5>::value, "Error");
+static_assert(std::is_nothrow_copy_assignable<pt6>::value, "Error");
+static_assert(!std::is_nothrow_copy_assignable<pt7>::value, "Error");
+static_assert(!std::is_nothrow_copy_assignable<pt8>::value, "Error");
+static_assert(!std::is_nothrow_copy_assignable<pt9>::value, "Error");
+static_assert(!std::is_nothrow_copy_assignable<pt10>::value, "Error");
+static_assert(std::is_nothrow_copy_assignable<pt11>::value, "Error");
+static_assert(std::is_nothrow_copy_assignable<pt12>::value, "Error");
+static_assert(!std::is_nothrow_copy_assignable<pt13>::value, "Error");
Index: testsuite/20_util/pair/assign.cc
===================================================================
--- testsuite/20_util/pair/assign.cc	(revision 0)
+++ testsuite/20_util/pair/assign.cc	(revision 0)
@@ -0,0 +1,177 @@
+// { dg-options "-std=c++11" }
+
+// Copyright (C) 2013 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/>.
+
+#include <utility>
+#include <tuple>
+#include <testsuite_hooks.h>
+#include <testsuite_counter_type.h>
+#include <testsuite_tr1.h>
+
+void test01()
+{
+  bool test __attribute__((unused)) = true;
+  using __gnu_test::counter_type;
+
+  typedef std::pair<int, counter_type> ptype;
+  ptype p1(0, 0);
+  ptype p2(1, 1);
+
+  counter_type::reset();
+
+  p1 = p2;
+
+  VERIFY( p1.first == 1 );
+  VERIFY( p1.second.val == 1 );
+  VERIFY( counter_type::copy_assign_count == 1 );
+}
+
+void test02()
+{
+  bool test __attribute__((unused)) = true;
+  using __gnu_test::counter_type;
+
+  typedef std::pair<int, counter_type> ptype;
+  ptype p1(0, 0);
+  ptype p2(1, 1);
+
+  counter_type::reset();
+
+  p1 = std::move(p2);
+
+  VERIFY( p1.first == 1 );
+  VERIFY( p1.second.val == 1 );
+  VERIFY( counter_type::move_assign_count == 1 );
+}
+
+void test03()
+{
+  bool test __attribute__((unused)) = true;
+
+  typedef std::pair<int&, int&> ptype;
+  int i = 0, j = 1;
+  ptype p1(i, j);
+  VERIFY( p1.first == 0 );
+  VERIFY( p1.second == 1 );
+
+  int k = 2, l = 3;
+  ptype p2(k, l);
+  VERIFY( p2.first == 2 );
+  VERIFY( p2.second == 3 );
+
+  p1 = p2;
+
+  VERIFY( p1.first == 2 );
+  VERIFY( p1.second == 3 );
+  VERIFY( p2.first == 2 );
+  VERIFY( p2.second == 3 );
+
+  VERIFY( i == 2 );
+
+  i = 0;
+  VERIFY( p1.first == 0 );
+}
+
+void test04()
+{
+  bool test __attribute__((unused)) = true;
+
+  typedef std::pair<int&, int> ptype;
+  int i = 0;
+  ptype p1(i, 1);
+  VERIFY( p1.first == 0 );
+  VERIFY( p1.second == 1 );
+
+  int j = 2;
+  ptype p2(j, 3);
+  VERIFY( p2.first == 2 );
+  VERIFY( p2.second == 3 );
+
+  p1 = p2;
+
+  VERIFY( p1.first == 2 );
+  VERIFY( p1.second == 3 );
+  VERIFY( p2.first == 2 );
+  VERIFY( p2.second == 3 );
+
+  VERIFY( i == 2 );
+
+  i = 0;
+  VERIFY( p1.first == 0 );
+}
+
+namespace __gnu_test
+{
+  struct MyStruct
+  {
+    int _i;
+
+    MyStruct()
+      : _i() { }
+    MyStruct(int i)
+      : _i(i) { }
+    MyStruct(const MyStruct& other)
+      : _i(other._i) { }
+    MyStruct(MyStruct&& other)
+      : _i(other._i)
+    { other._i = -1; }
+
+    MyStruct&
+    operator=(const MyStruct& other)
+    { _i = other._i; }
+
+    MyStruct&
+    operator=(MyStruct&& other)
+    {
+      _i = other._i;
+      other._i = -1;
+    }
+  };
+}
+
+void test05()
+{
+  bool test __attribute__((unused)) = true;
+
+  typedef std::pair<__gnu_test::MyStruct, __gnu_test::MyStruct> ptype1;
+  typedef std::pair<__gnu_test::MyStruct, const __gnu_test::MyStruct> ptype2;
+  
+  static_assert(std::is_move_assignable<ptype1>::value, "Error");
+  static_assert(!std::is_move_assignable<ptype2>::value, "Error");
+  static_assert(std::is_assignable<ptype1&, ptype2&&>::value, "Error");
+
+  ptype1 p1(1, 2);
+  ptype2 p2(3, 4);
+
+  p1 = std::move(p2);
+
+  VERIFY( p1.first._i == 3 );
+  VERIFY( p1.second._i == 4 );
+  VERIFY( p2.first._i == -1 );
+  VERIFY( p2.second._i == 4 );
+}
+
+int main()
+{
+  test01();
+  test02();
+  test03();
+  test04();
+  test05();
+  return 0;
+}
Index: testsuite/20_util/pair/is_move_assignable.cc
===================================================================
--- testsuite/20_util/pair/is_move_assignable.cc	(revision 0)
+++ testsuite/20_util/pair/is_move_assignable.cc	(revision 0)
@@ -0,0 +1,59 @@
+// { dg-do compile }
+// { dg-options "-std=c++11" }
+
+// Copyright (C) 2013 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/>.
+
+#include <type_traits>
+#include <utility>
+#include <testsuite_tr1.h>
+
+using namespace __gnu_test;
+
+typedef std::pair<int, int>						pt1;
+typedef std::pair<int, double>						pt2;
+typedef std::pair<NoexceptCopyAssignClass, NoexceptCopyAssignClass>	pt3;
+typedef std::pair<ExceptCopyAssignClass, ExceptCopyAssignClass>		pt4;
+typedef std::pair<ExceptCopyAssignClass, double>			pt5;
+typedef std::pair<NoexceptCopyAssignClass, ExceptCopyAssignClass>	pt6;
+typedef std::pair<const int, int>					pt7;
+typedef std::pair<int, const int>					pt8;
+typedef std::pair<NoexceptMoveAssignClass, NoexceptMoveAssignClass>	pt9;
+typedef std::pair<ExceptMoveAssignClass, ExceptMoveAssignClass>		pt10;
+typedef std::pair<ExceptMoveAssignClass, double>			pt11;
+typedef std::pair<DeletedMoveAssignClass, ExceptMoveAssignClass>	pt12;
+typedef std::pair<DeletedMoveAssignClass, DeletedMoveAssignClass>	pt13;
+typedef std::pair<ExceptMoveAssignClass, DeletedMoveAssignClass>	pt14;
+typedef std::pair<int, int&>						pt15;
+typedef std::pair<int, const int&>					pt16;
+
+static_assert(std::is_move_assignable<pt1>::value, "Error");
+static_assert(std::is_move_assignable<pt2>::value, "Error");
+static_assert(std::is_move_assignable<pt3>::value, "Error");
+static_assert(std::is_move_assignable<pt4>::value, "Error");
+static_assert(std::is_move_assignable<pt5>::value, "Error");
+static_assert(std::is_move_assignable<pt6>::value, "Error");
+static_assert(!std::is_move_assignable<pt7>::value, "Error");
+static_assert(!std::is_move_assignable<pt8>::value, "Error");
+static_assert(std::is_move_assignable<pt9>::value, "Error");
+static_assert(std::is_move_assignable<pt10>::value, "Error");
+static_assert(std::is_move_assignable<pt11>::value, "Error");
+static_assert(!std::is_move_assignable<pt12>::value, "Error");
+static_assert(!std::is_move_assignable<pt13>::value, "Error");
+static_assert(!std::is_move_assignable<pt14>::value, "Error");
+static_assert(std::is_move_assignable<pt15>::value, "Error");
+static_assert(!std::is_move_assignable<pt16>::value, "Error");
Index: testsuite/20_util/pair/is_copy_assignable.cc
===================================================================
--- testsuite/20_util/pair/is_copy_assignable.cc	(revision 0)
+++ testsuite/20_util/pair/is_copy_assignable.cc	(revision 0)
@@ -0,0 +1,53 @@
+// { dg-do compile }
+// { dg-options "-std=c++11" }
+
+// Copyright (C) 2013 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/>.
+
+#include <type_traits>
+#include <utility>
+#include <testsuite_tr1.h>
+
+using namespace __gnu_test;
+
+typedef std::pair<int, int>						pt1;
+typedef std::pair<int, double>						pt2;
+typedef std::pair<const int, int>					pt3;
+typedef std::pair<int, const int>					pt4;
+//typedef std::pair<int, const int>&					pt5;
+typedef std::pair<NoexceptCopyAssignClass, NoexceptCopyAssignClass>	pt6;
+typedef std::pair<ExceptCopyAssignClass, ExceptCopyAssignClass>		pt7;
+typedef std::pair<ExceptCopyAssignClass, double>			pt8;
+typedef std::pair<NoexceptCopyAssignClass, ExceptCopyAssignClass>	pt9;
+typedef std::pair<int, DeletedCopyAssignClass>				pt10;
+typedef std::pair<int, int&>						pt11;
+typedef std::pair<int&, int&>						pt12;
+typedef std::pair<int, const int&>					pt13;
+
+static_assert(std::is_copy_assignable<pt1>::value, "Error");
+static_assert(std::is_copy_assignable<pt2>::value, "Error");
+static_assert(!std::is_copy_assignable<pt3>::value, "Error");
+static_assert(!std::is_copy_assignable<pt4>::value, "Error");
+//static_assert(!std::is_copy_assignable<pt5>::value, "Error");
+static_assert(std::is_copy_assignable<pt6>::value, "Error");
+static_assert(std::is_copy_assignable<pt7>::value, "Error");
+static_assert(std::is_copy_assignable<pt8>::value, "Error");
+static_assert(std::is_copy_assignable<pt9>::value, "Error");
+static_assert(!std::is_copy_assignable<pt10>::value, "Error");
+static_assert(std::is_copy_assignable<pt11>::value, "Error");
+static_assert(std::is_copy_assignable<pt12>::value, "Error");
+static_assert(!std::is_copy_assignable<pt13>::value, "Error");