re PR c++/67844 (Cannot make tuple of class with template constructor)

2015-10-05  Ville Voutilainen  <ville.voutilainen@gmail.com>

	PR 67844.
	* include/std/tuple (_TC::_NonNestedTuple): Eagerly reject
	conversions from tuple types same as the target tuple.
	* testsuite/20_util/tuple/67844.cc: New.
	* testsuite/20_util/tuple/cons/nested_tuple_construct.cc: Add
	a missing copyright header.

From-SVN: r228468

libstdc++-v3/ChangeLog

+2015-10-05  Ville Voutilainen  <ville.voutilainen@gmail.com>
+
+	PR 67844.
+	* include/std/tuple (_TC::_NonNestedTuple): Eagerly reject
+	conversions from tuple types same as the target tuple.
+	* testsuite/20_util/tuple/67844.cc: New.
+	* testsuite/20_util/tuple/cons/nested_tuple_construct.cc: Add
+	a missing copyright header.
+
 2015-10-03  Jonathan Wakely  <jwakely@redhat.com>
 
 	* python/libstdcxx/v6/printers.py (StdExpAnyPrinter): Remove support

libstdc++-v3/include/std/tuple

@@ -457,6 +457,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       }
     };
 
+  template<typename... _Elements>
+    class tuple;
 
   // Concept utility functions, reused in conditionally-explicit
   // constructors.
@@ -490,7 +492,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     template<typename _SrcTuple>
     static constexpr bool _NonNestedTuple()
     {
-      return  __and_<__not_<is_convertible<_SrcTuple, _Elements...>>,
+      return  __and_<__not_<is_same<tuple<_Elements...>,
+                                   typename remove_cv<
+                                     typename remove_reference<_SrcTuple>::type
+                                   >::type>>,
+                     __not_<is_convertible<_SrcTuple, _Elements...>>,
                      __not_<is_constructible<_Elements..., _SrcTuple>>
               >::value;
     }

libstdc++-v3/testsuite/20_util/tuple/67844.cc

+// { dg-do compile }
+
+// 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/>.
+
+// libstdc++/67844
+
+#include <tuple>
+
+struct A
+{
+  template <typename T>
+  A(T)
+  {
+  }
+
+  A(const A&) = default;
+  A(A&&) = default;
+  A& operator=(const A&) = default;
+  A& operator=(A&&) = default;
+  ~A() = default;
+};
+
+int main()
+{
+  auto x = A{7};
+  std::make_tuple(x);
+}
+

libstdc++-v3/testsuite/20_util/tuple/cons/nested_tuple_construct.cc

+// 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/>.
+
 #include <string>
 #include <tuple>
 #include <testsuite_hooks.h>