PR libstdc++/80229 restore support for shared_ptr<function type>

	PR libstdc++/80229
	* include/bits/shared_ptr_base.h
	(__shared_ptr::_M_enable_shared_from_this_with): Change parameters to
	non-const and then use remove_cv to get unqualified type.
	* testsuite/20_util/enable_shared_from_this/members/const.cc: Don't
	cast away constness on object created const.
	* testsuite/20_util/shared_ptr/cons/80229.cc: New test.

From-SVN: r246520

libstdc++-v3/ChangeLog

+2017-03-28  Jonathan Wakely  <jwakely@redhat.com>
+
+	PR libstdc++/80229
+	* include/bits/shared_ptr_base.h
+	(__shared_ptr::_M_enable_shared_from_this_with): Change parameters to
+	non-const and then use remove_cv to get unqualified type.
+	* testsuite/20_util/enable_shared_from_this/members/const.cc: Don't
+	cast away constness on object created const.
+	* testsuite/20_util/shared_ptr/cons/80229.cc: New test.
+
 2017-03-26  Markus Trippelsdorf  <markus@trippelsdorf.de>
 
 	PR libstdc++/80183

libstdc++-v3/include/bits/shared_ptr_base.h

@@ -1363,17 +1363,17 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 	struct __has_esft_base<_Yp, __void_t<__esft_base_t<_Yp>>>
 	: __not_<is_array<_Tp>> { }; // No enable shared_from_this for arrays
 
-      template<typename _Yp>
-	typename enable_if<__has_esft_base<_Yp>::value>::type
-	_M_enable_shared_from_this_with(const _Yp* __p) noexcept
+      template<typename _Yp, typename _Yp2 = typename remove_cv<_Yp>::type>
+	typename enable_if<__has_esft_base<_Yp2>::value>::type
+	_M_enable_shared_from_this_with(_Yp* __p) noexcept
 	{
 	  if (auto __base = __enable_shared_from_this_base(_M_refcount, __p))
-	    __base->_M_weak_assign(const_cast<_Yp*>(__p), _M_refcount);
+	    __base->_M_weak_assign(const_cast<_Yp2*>(__p), _M_refcount);
 	}
 
-      template<typename _Yp>
-	typename enable_if<!__has_esft_base<_Yp>::value>::type
-	_M_enable_shared_from_this_with(const _Yp*) noexcept
+      template<typename _Yp, typename _Yp2 = typename remove_cv<_Yp>::type>
+	typename enable_if<!__has_esft_base<_Yp2>::value>::type
+	_M_enable_shared_from_this_with(_Yp*) noexcept
 	{ }
 
       void*

libstdc++-v3/testsuite/20_util/enable_shared_from_this/members/const.cc

@@ -32,9 +32,9 @@ test01()
 {
   struct X : public std::enable_shared_from_this<X> { };
   using CX = const X;
-  std::shared_ptr<CX> p(new X);
+  std::shared_ptr<CX> p(new CX);
   VERIFY( share_ownership(p->shared_from_this(), p) );
-  p.reset(new CX);
+  p.reset(new X);
   VERIFY( share_ownership(p->shared_from_this(), p) );
   auto p2 = std::const_pointer_cast<X>(p)->shared_from_this();
   VERIFY( share_ownership(p2, p) );

libstdc++-v3/testsuite/20_util/shared_ptr/cons/80229.cc

+// Copyright (C) 2017 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-do compile { target c++11 } }
+
+#include <memory>
+
+// PR libstdc++/80229
+
+void del(void(*)());
+void the_func();
+std::shared_ptr<void()> ee(&the_func, &del);