Prevent recursive instantiation in std::function

	PR libstdc++/69005
	PR libstdc++/69222
	* include/std/functional (function::_Invoke): Remove, use result_of.
	(function::_Callable): Replace alias template with class template
	and use partial specialization instead of _NotSelf alias template.
	(function(_Functor)): Add "not self" constraint so that _Callable is
	not used while type is incomplete.
	* testsuite/20_util/function/69222.cc: New.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@232273 138bc75d-0d04-0410-961f-82ee72b054a4

3 files changed, 47 insertions, 11 deletions

diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index ad4cdc3fe01..d6fa5319b53 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,3 +1,14 @@
+2016-01-12  Jonathan Wakely  <jwakely@redhat.com>
+
+	PR libstdc++/69005
+	PR libstdc++/69222
+	* include/std/functional (function::_Invoke): Remove, use result_of.
+	(function::_Callable): Replace alias template with class template
+	and use partial specialization instead of _NotSelf alias template.
+	(function(_Functor)): Add "not self" constraint so that _Callable is
+	not used while type is incomplete.
+	* testsuite/20_util/function/69222.cc: New.
+
 2016-01-11  Jonathan Wakely  <jwakely@redhat.com>
 
 	PR libstdc++/60976
diff --git a/libstdc++-v3/include/std/functional b/libstdc++-v3/include/std/functional
index 8023ab9aa4b..557156a358c 100644
--- a/libstdc++-v3/include/std/functional
+++ b/libstdc++-v3/include/std/functional
@@ -1846,20 +1846,14 @@ _GLIBCXX_MEM_FN_TRAITS(&&, false_type, true_type)
     {
       typedef _Res _Signature_type(_ArgTypes...);
 
-      template<typename _Functor>
-	using _Invoke
-	= decltype(std::__callable_functor(std::declval<_Functor&>())
-		   (std::declval<_ArgTypes>()...) );
+      template<typename _Func,
+	       typename _Res2 = typename result_of<_Func(_ArgTypes...)>::type>
+	struct _Callable : __check_func_return_type<_Res2, _Res> { };
 
       // Used so the return type convertibility checks aren't done when
       // performing overload resolution for copy construction/assignment.
       template<typename _Tp>
-	using _NotSelf = __not_<is_same<_Tp, function>>;
-
-      template<typename _Functor>
-	using _Callable
-	  = __and_<_NotSelf<_Functor>,
-		   __check_func_return_type<_Invoke<_Functor>, _Res>>;
+	struct _Callable<function, _Tp> : false_type { };
 
       template<typename _Cond, typename _Tp>
 	using _Requires = typename enable_if<_Cond::value, _Tp>::type;
@@ -1924,6 +1918,7 @@ _GLIBCXX_MEM_FN_TRAITS(&&, false_type, true_type)
        *  reference_wrapper<F>, this function will not throw.
        */
       template<typename _Functor,
+	       typename = _Requires<__not_<is_same<_Functor, function>>, void>,
 	       typename = _Requires<_Callable<_Functor>, void>>
 	function(_Functor);
 
@@ -2116,7 +2111,7 @@ _GLIBCXX_MEM_FN_TRAITS(&&, false_type, true_type)
     }
 
   template<typename _Res, typename... _ArgTypes>
-    template<typename _Functor, typename>
+    template<typename _Functor, typename, typename>
       function<_Res(_ArgTypes...)>::
       function(_Functor __f)
       : _Function_base()
diff --git a/libstdc++-v3/testsuite/20_util/function/69222.cc b/libstdc++-v3/testsuite/20_util/function/69222.cc
new file mode 100644
index 00000000000..7c9dfecb547
--- /dev/null
+++ b/libstdc++-v3/testsuite/20_util/function/69222.cc
@@ -0,0 +1,30 @@
+// Copyright (C) 2016 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 <functional>
+
+// Reduced from c++/69005
+struct Foo {
+  std::function<void(Foo)> f;
+};
+
+extern Foo exfoo;
+Foo f(exfoo);
+Foo& r = f = exfoo;