[Bug libstdc++/63500] [4.9/5 Regression] bug in debug version of std::make_move_iterator?

[Jonathan Wakely]

On 15/10/14 22:06 +0200, François Dumont wrote:
>On 15/10/2014 13:10, Jonathan Wakely wrote:
>>
>>I find this much easier to read:
>>
>>#if __cplusplus < 201103L
>>     typedef _Is_contiguous_sequence<_Sequence> __tag;
>>#else
>>     using __lvalref = std::is_lvalue_reference<
>>       typename std::iterator_traits<_InputIterator>::reference>;
>>     using __contiguous = _Is_contiguous_sequence<_Sequence>;
>>     using __tag = typename std::conditional<__lvalref::value, 
>>__contiguous,
>>std::__false_type>::type;
>>#endif
>>     return __foreign_iterator_aux3(__it, __other, __other_end, __tag());
>>
>>It only has one preprocessor condition and it avoids mismatched
>>parentheses caused by opening the function parameter list once but
>>closing it twice in two different branches.
>>
>>
>That's much better indeed.
>
>    Shall we go with this ? Of course we are simply considering that 
>we can't check for foreign iterators when some iterator adapters comes 
>in-between. I hope one day to detect invalid usages even in this 
>context.
>
>2014-10-16  François Dumont  <fdumont@gcc.gnu.org>
>
>    PR libstdc++/63500
>    * include/debug/functions.h (__foreign_iterator_aux2): Do not check for
>    foreign iterators if input iterators returns rvalue reference.
>    * testsuite/23_containers/vector/63500.cc: New.
>
>François
>

As this is a regression it should go on the 4.9 branch too.

>Index: include/debug/functions.h
>===================================================================
>--- include/debug/functions.h	(revision 216279)
>+++ include/debug/functions.h	(working copy)
>@@ -34,7 +34,7 @@
> 					  // _Iter_base
> #include <bits/cpp_type_traits.h>	  // for __is_integer
> #include <bits/move.h>                    // for __addressof and addressof
>-# include <bits/stl_function.h>		  // for less
>+#include <bits/stl_function.h>		  // for less
> #if __cplusplus >= 201103L
> # include <type_traits>			  // for is_lvalue_reference and __and_
> #endif
>@@ -252,8 +252,16 @@
> 			    const _InputIterator& __other,
> 			    const _InputIterator& __other_end)
>     {
>-      return __foreign_iterator_aux3(__it, __other, __other_end,
>-				     _Is_contiguous_sequence<_Sequence>());
>+#if __cplusplus < 201103L
>+      typedef _Is_contiguous_sequence<_Sequence> __tag;
>+#else
>+      using __lvalref = std::is_lvalue_reference<
>+	typename std::iterator_traits<_InputIterator>::reference>;
>+      using __contiguous = _Is_contiguous_sequence<_Sequence>;
>+      using __tag = typename std::conditional<__lvalref::value, __contiguous,
>+					      std::__false_type>::type;
>+#endif
>+      return __foreign_iterator_aux3(__it, __other, __other_end, __tag());
>     }
> 
>   /* Handle the case where we aren't really inserting a range after all */
>Index: testsuite/23_containers/vector/63500.cc
>===================================================================
>--- testsuite/23_containers/vector/63500.cc	(revision 0)
>+++ testsuite/23_containers/vector/63500.cc	(working copy)
>@@ -0,0 +1,39 @@
>+// -*- C++ -*-
>+
>+// Copyright (C) 2014 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 <iterator>
>+#include <debug/vector>
>+
>+class Foo
>+{};
>+
>+void
>+test01()
>+{
>+  __gnu_debug::vector<std::unique_ptr<Foo>> v;
>+  __gnu_debug::vector<std::unique_ptr<Foo>> w;
>+
>+  v.insert(end(v),
>+	   make_move_iterator(begin(w)),
>+	   make_move_iterator(end(w)));
>+}