[patch] libstdc++/65279 fix scoped_allocator_adaptor assignment

[Jonathan Wakely <jwakely at redhat dot com>]

std::scoped_allocator_adaptor declares a move constructor but not a
copy assignment operator, which means the copy assignment operator is
defined as deleted, and so scoped_allocator_adaptor<A...> is not
CopyAssignable. (This seems to be exactly what the standard requires,
but that's clearly a defect in the standard and I've reported it).

This is a regression on all branches since 4.7 (because 4.7 didn't
implement the final rules about deleting the copy assignment).

Tested x86_64-linux, committed to trunk so far, with backports for 4.8
and 4.9 to follow.

commit da61a6279a286d53a2d6e2dca6b3e4a36ddfbf59
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Mon Mar 2 16:32:09 2015 +0000

    	PR libstdc++/65279
    	* include/std/scoped_allocator (__inner_type_impl,
    	scoped_allocator_adaptor): Add defaulted copy assignment and move
    	assignment operators.
    	* testsuite/20_util/scoped_allocator/65279.cc: New.

diff --git a/libstdc++-v3/include/std/scoped_allocator b/libstdc++-v3/include/std/scoped_allocator
index 1be10b2..d163edd 100644
--- a/libstdc++-v3/include/std/scoped_allocator
+++ b/libstdc++-v3/include/std/scoped_allocator
@@ -105,6 +105,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       __inner_type_impl() = default;
       __inner_type_impl(const __inner_type_impl&) = default;
       __inner_type_impl(__inner_type_impl&&) = default;
+      __inner_type_impl& operator=(const __inner_type_impl&) = default;
+      __inner_type_impl& operator=(__inner_type_impl&&) = default;
       
       template<typename _Alloc>
       __inner_type_impl(const __inner_type_impl<_Alloc>& __other)
@@ -136,6 +138,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       __inner_type_impl() = default;
       __inner_type_impl(const __inner_type_impl&) = default;
       __inner_type_impl(__inner_type_impl&&) = default;
+      __inner_type_impl& operator=(const __inner_type_impl&) = default;
+      __inner_type_impl& operator=(__inner_type_impl&&) = default;
       
       template<typename... _Allocs>
       __inner_type_impl(const __inner_type_impl<_Allocs...>& __other)
@@ -310,6 +314,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
           _M_inner(std::move(__other._M_inner))
         { }
 
+      scoped_allocator_adaptor&
+      operator=(const scoped_allocator_adaptor&) = default;
+
+      scoped_allocator_adaptor&
+      operator=(scoped_allocator_adaptor&&) = default;
+
       inner_allocator_type& inner_allocator() noexcept
       { return _M_inner._M_get(this); }
 
diff --git a/libstdc++-v3/testsuite/20_util/scoped_allocator/65279.cc b/libstdc++-v3/testsuite/20_util/scoped_allocator/65279.cc
new file mode 100644
index 0000000..786d403
--- /dev/null
+++ b/libstdc++-v3/testsuite/20_util/scoped_allocator/65279.cc
@@ -0,0 +1,54 @@
+// Copyright (C) 2015 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++11" }
+// { dg-do compile }
+
+#include <memory>
+#include <type_traits>
+#include <scoped_allocator>
+
+template<typename T>
+  struct Allocator : std::allocator<T>
+  {
+    template<typename U>
+      struct rebind { using other = Allocator<U>; };
+
+    using propagate_on_container_copy_assignment = std::true_type;
+    using propagate_on_container_move_assignment = std::true_type;
+  };
+
+template<typename... T>
+  using alloc = std::scoped_allocator_adaptor<Allocator<T>...>;
+
+void
+test01()
+{
+  // Test partial specialization for sizeof...(InnerAlloc) == 0
+  alloc<int> a;
+  a = a;
+  a = std::move(a);
+}
+
+void
+test02()
+{
+  // Test partial specialization for sizeof...(InnerAlloc) >= 1
+  alloc<int, char> a;
+  a = a;
+  a = std::move(a);
+}