* include/std/functional (function::function(F)): LWG 2132: Disable

	constructor if argument isn't callable.
	* testsuite/20_util/function/cons/callable.cc: New.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@186947 138bc75d-0d04-0410-961f-82ee72b054a4

diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index b91668a..53d94d5 100644 (file)
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,3 +1,9 @@
+2012-04-29  Jonathan Wakely  <jwakely.gcc@gmail.com>
+
+       * include/std/functional (function::function(F)): LWG 2132: Disable
+       constructor if argument isn't callable.
+       * testsuite/20_util/function/cons/callable.cc: New.
+
 2012-04-29  Marc Glisse  <marc.glisse@inria.fr>
 
        PR libstdc++/22200

diff --git a/libstdc++-v3/include/std/functional b/libstdc++-v3/include/std/functional
index 980c6ab..0edb4f1 100644 (file)
--- a/libstdc++-v3/include/std/functional
+++ b/libstdc++-v3/include/std/functional
@@ -1856,7 +1856,7 @@ _GLIBCXX_HAS_NESTED_TYPE(result_type)
       {
        typedef _Function_base::_Base_manager<_Functor*> _Base;
 
-    public:
+      public:
        static bool
        _M_manager(_Any_data& __dest, const _Any_data& __source,
                   _Manager_operation __op)
@@ -1994,7 +1994,7 @@ _GLIBCXX_HAS_NESTED_TYPE(result_type)
       typedef _Simple_type_wrapper<_Functor> _Wrapper;
       typedef _Function_base::_Base_manager<_Wrapper> _Base;
 
-     public:
+    public:
       static bool
       _M_manager(_Any_data& __dest, const _Any_data& __source,
                 _Manager_operation __op)
@@ -2038,7 +2038,23 @@ _GLIBCXX_HAS_NESTED_TYPE(result_type)
     {
       typedef _Res _Signature_type(_ArgTypes...);
 
-      struct _Useless { };
+      template<typename _Functor>
+       using _Invoke = decltype(__callable_functor(std::declval<_Functor&>())
+                                (std::declval<_ArgTypes>()...) );
+
+      template<typename _CallRes, typename _Res1>
+       struct _CheckResult
+       : is_convertible<_CallRes, _Res1> { };
+
+      template<typename _CallRes>
+       struct _CheckResult<_CallRes, void>
+       : true_type { };
+
+      template<typename _Functor>
+       using _Callable = _CheckResult<_Invoke<_Functor>, _Res>;
+
+      template<typename _Cond, typename _Tp>
+       using _Requires = typename enable_if<_Cond::value, _Tp>::type;
 
     public:
       typedef _Res result_type;
@@ -2099,11 +2115,9 @@ _GLIBCXX_HAS_NESTED_TYPE(result_type)
        *  If @a __f is a non-NULL function pointer or an object of type @c
        *  reference_wrapper<F>, this function will not throw.
        */
-      template<typename _Functor>
-       function(_Functor __f,
-                typename enable_if<
-                          !is_integral<_Functor>::value, _Useless>::type
-                  = _Useless());
+      template<typename _Functor,
+              typename = _Requires<_Callable<_Functor>, void>>
+       function(_Functor);
 
       /**
        *  @brief %Function assignment operator.
@@ -2178,7 +2192,7 @@ _GLIBCXX_HAS_NESTED_TYPE(result_type)
        *  reference_wrapper<F>, this function will not throw.
        */
       template<typename _Functor>
-       typename enable_if<!is_integral<_Functor>::value, function&>::type
+       _Requires<_Callable<_Functor>, function&>
        operator=(_Functor&& __f)
        {
          function(std::forward<_Functor>(__f)).swap(*this);
@@ -2187,7 +2201,7 @@ _GLIBCXX_HAS_NESTED_TYPE(result_type)
 
       /// @overload
       template<typename _Functor>
-       typename enable_if<!is_integral<_Functor>::value, function&>::type
+       function&
        operator=(reference_wrapper<_Functor> __f) noexcept
        {
          function(__f).swap(*this);
@@ -2294,11 +2308,9 @@ _GLIBCXX_HAS_NESTED_TYPE(result_type)
     }
 
   template<typename _Res, typename... _ArgTypes>
-    template<typename _Functor>
+    template<typename _Functor, typename>
       function<_Res(_ArgTypes...)>::
-      function(_Functor __f,
-              typename enable_if<
-                       !is_integral<_Functor>::value, _Useless>::type)
+      function(_Functor __f)
       : _Function_base()
       {
        typedef _Function_handler<_Signature_type, _Functor> _My_handler;

diff --git a/libstdc++-v3/testsuite/20_util/function/cons/callable.cc b/libstdc++-v3/testsuite/20_util/function/cons/callable.cc
new file mode 100644 (file)
index 0000000..209c404
--- /dev/null
+++ b/libstdc++-v3/testsuite/20_util/function/cons/callable.cc
@@ -0,0 +1,51 @@
+// { dg-options "-std=gnu++0x" }
+// { dg-do compile }
+
+// Copyright (C) 2012 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>
+#include <testsuite_hooks.h>
+
+void* f(std::function<void()>) { return nullptr; }
+int f(std::function<void(int)>) { return 1; }
+
+void test01()
+{
+  void* p __attribute__((unused));
+  int i __attribute__((unused));
+
+  p = f([] { });
+  i = f([] (int) { });
+}
+
+void g(std::function<void()>) { }
+void h(std::function<int(int)>) { }
+
+void test02()
+{
+  g([] { return "ignored"; });
+  h([] (char c) { return c; });
+}
+
+int main()
+{
+  test01();
+  test02();
+
+  return 0;
+}