Index: include/std/functional
===================================================================
--- include/std/functional	(revision 174047)
+++ include/std/functional	(working copy)
@@ -1210,7 +1210,8 @@
 
       // Call as const
       template<typename... _Args, typename _Result
-	= decltype( std::declval<const _Functor>()(
+	= decltype( std::declval<typename enable_if<(sizeof...(_Args) >= 0),
+		       typename add_const<_Functor>::type>::type>()(
 	      _Mu<_Bound_args>()( std::declval<const _Bound_args&>(),
 				  std::declval<tuple<_Args...>&>() )... ) )>
 	_Result
@@ -1223,7 +1224,8 @@
 
       // Call as volatile
       template<typename... _Args, typename _Result
-	= decltype( std::declval<volatile _Functor>()(
+	= decltype( std::declval<typename enable_if<(sizeof...(_Args) >= 0),
+                       typename add_volatile<_Functor>::type>::type>()(
 	      _Mu<_Bound_args>()( std::declval<volatile _Bound_args&>(),
 				  std::declval<tuple<_Args...>&>() )... ) )>
 	_Result
@@ -1236,7 +1238,8 @@
 
       // Call as const volatile
       template<typename... _Args, typename _Result
-	= decltype( std::declval<const volatile _Functor>()(
+	= decltype( std::declval<typename enable_if<(sizeof...(_Args) >= 0),
+                       typename add_cv<_Functor>::type>::type>()(
 	      _Mu<_Bound_args>()( std::declval<const volatile _Bound_args&>(),
 				  std::declval<tuple<_Args...>&>() )... ) )>
 	_Result
Index: testsuite/20_util/bind/cv_quals_2.cc
===================================================================
--- testsuite/20_util/bind/cv_quals_2.cc	(revision 0)
+++ testsuite/20_util/bind/cv_quals_2.cc	(revision 0)
@@ -0,0 +1,49 @@
+// Copyright (C) 2011 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++0x" }
+
+#include <functional>
+#include <testsuite_hooks.h>
+
+struct X
+{
+  int operator()() const { return 0; }
+  int operator()() volatile { return 1; }
+  int operator()() const volatile { return 2; }
+  void operator()() { };
+};
+
+void test01()
+{
+  bool test __attribute__((unused)) = true;
+
+  const auto b0 = std::bind(X());
+  VERIFY( b0() == 0 );
+
+  volatile auto b1 = std::bind(X());
+  VERIFY( b1() == 1 );
+
+  const volatile auto b2 = std::bind(X());
+  VERIFY( b2() == 2 );
+}
+
+int main()
+{
+  test01();
+  return 0;
+}
Index: testsuite/20_util/bind/49058_1.cc
===================================================================
--- testsuite/20_util/bind/49058_1.cc	(revision 0)
+++ testsuite/20_util/bind/49058_1.cc	(revision 0)
@@ -0,0 +1,34 @@
+// { dg-options "-pedantic -std=gnu++0x" }
+// { dg-do compile }
+
+// Copyright (C) 2011 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 <functional>
+
+// PR libstdc++/49058
+
+struct F
+{
+  void
+  operator()();
+};
+
+void f()
+{
+  std::bind( F() );
+}
Index: testsuite/20_util/bind/49058_2.cc
===================================================================
--- testsuite/20_util/bind/49058_2.cc	(revision 0)
+++ testsuite/20_util/bind/49058_2.cc	(revision 0)
@@ -0,0 +1,28 @@
+// { dg-options "-pedantic -std=gnu++0x" }
+// { dg-do compile }
+
+// Copyright (C) 2011 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 <functional>
+
+// PR libstdc++/49058
+
+void f()
+{
+  std::bind( []{} );
+}