PR libstdc++/83427 detect weak result type from noexcept functions

	PR libstdc++/83427
	* include/bits/refwrap.h (_Maybe_unary_or_binary_function): Move here
	from <bits/std_function.h>.
	(_Mem_fn_traits_base, _Mem_fn_traits): Move here, from <functional>.
	(_Weak_result_type_impl, _Reference_wrapper_base): Deduce noexcept
	for function types. Remove partial specializations for member
	functions.
	(_Weak_result_type_impl): Remove unused partial specializations for
	non-referenceable function types and for references to functions.
	(_Weak_result_type_memfun, _Reference_wrapper_base_memfun): New
	helpers to handle member functions via _Mem_fn_traits.
	(_Weak_result_type, reference_wrapper): Derive from new helpers.
	* include/bits/std_function.h (_Maybe_unary_or_binary_function): Move
	to <bits/refwrap.h>.
	* include/std/functional (_Pack, _AllConvertible, _NotSame): Remove.
	(_Mem_fn_traits_base, _Mem_fn_traits): Move to <bits/refwrap.h>.
	* testsuite/20_util/bind/83427.cc: New test.
	* testsuite/20_util/bind/refqual.cc: Add noexcept to functions and
	check for weak result types.
	* testsuite/20_util/reference_wrapper/83427.cc: New test.

From-SVN: r255651

libstdc++-v3/ChangeLog

 2017-12-14  Jonathan Wakely  <jwakely@redhat.com>
 
+	PR libstdc++/83427
+	* include/bits/refwrap.h (_Maybe_unary_or_binary_function): Move here
+	from <bits/std_function.h>.
+	(_Mem_fn_traits_base, _Mem_fn_traits): Move here, from <functional>.
+	(_Weak_result_type_impl, _Reference_wrapper_base): Deduce noexcept
+	for function types. Remove partial specializations for member
+	functions.
+	(_Weak_result_type_impl): Remove unused partial specializations for
+	non-referenceable function types and for references to functions.
+	(_Weak_result_type_memfun, _Reference_wrapper_base_memfun): New
+	helpers to handle member functions via _Mem_fn_traits.
+	(_Weak_result_type, reference_wrapper): Derive from new helpers.
+	* include/bits/std_function.h (_Maybe_unary_or_binary_function): Move
+	to <bits/refwrap.h>.
+	* include/std/functional (_Pack, _AllConvertible, _NotSame): Remove.
+	(_Mem_fn_traits_base, _Mem_fn_traits): Move to <bits/refwrap.h>.
+	* testsuite/20_util/bind/83427.cc: New test.
+	* testsuite/20_util/bind/refqual.cc: Add noexcept to functions and
+	check for weak result types.
+	* testsuite/20_util/reference_wrapper/83427.cc: New test.
+
 	* testsuite/26_numerics/complex/inserters_extractors/char/dr2714.cc:
 	Add tests using noskipws.
 

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

@@ -49,25 +49,6 @@ namespace std _GLIBCXX_VISIBILITY(default)
 _GLIBCXX_BEGIN_NAMESPACE_VERSION
 
   /**
-   * Derives from @c unary_function or @c binary_function, or perhaps
-   * nothing, depending on the number of arguments provided. The
-   * primary template is the basis case, which derives nothing.
-   */
-  template<typename _Res, typename... _ArgTypes>
-    struct _Maybe_unary_or_binary_function { };
-
-  /// Derives from @c unary_function, as appropriate.
-  template<typename _Res, typename _T1>
-    struct _Maybe_unary_or_binary_function<_Res, _T1>
-    : std::unary_function<_T1, _Res> { };
-
-  /// Derives from @c binary_function, as appropriate.
-  template<typename _Res, typename _T1, typename _T2>
-    struct _Maybe_unary_or_binary_function<_Res, _T1, _T2>
-    : std::binary_function<_T1, _T2, _Res> { };
-
-
-  /**
    *  @brief Exception class thrown when class template function's
    *  operator() is called with an empty target.
    *  @ingroup exceptions

libstdc++-v3/include/std/functional

@@ -55,7 +55,8 @@
 #include <type_traits>
 #include <bits/functional_hash.h>
 #include <bits/invoke.h>
-#include <bits/std_function.h>
+#include <bits/refwrap.h>	// std::reference_wrapper and _Mem_fn_traits
+#include <bits/std_function.h>	// std::function
 #if __cplusplus > 201402L
 # include <unordered_map>
 # include <vector>
@@ -82,68 +83,6 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     }
 #endif
 
-  template<typename... _Types>
-    struct _Pack : integral_constant<size_t, sizeof...(_Types)>
-    { };
-
-  template<typename _From, typename _To, bool = _From::value == _To::value>
-    struct _AllConvertible : false_type
-    { };
-
-  template<typename... _From, typename... _To>
-    struct _AllConvertible<_Pack<_From...>, _Pack<_To...>, true>
-    : __and_<is_convertible<_From, _To>...>
-    { };
-
-  template<typename _Tp1, typename _Tp2>
-    using _NotSame = __not_<is_same<typename std::decay<_Tp1>::type,
-				    typename std::decay<_Tp2>::type>>;
-
-  template<typename _Signature>
-    struct _Mem_fn_traits;
-
-  template<typename _Res, typename _Class, typename... _ArgTypes>
-    struct _Mem_fn_traits_base
-    {
-      using __result_type = _Res;
-      using __maybe_type
-	= _Maybe_unary_or_binary_function<_Res, _Class*, _ArgTypes...>;
-      using __arity = integral_constant<size_t, sizeof...(_ArgTypes)>;
-    };
-
-#define _GLIBCXX_MEM_FN_TRAITS2(_CV, _REF, _LVAL, _RVAL)		\
-  template<typename _Res, typename _Class, typename... _ArgTypes>	\
-    struct _Mem_fn_traits<_Res (_Class::*)(_ArgTypes...) _CV _REF>	\
-    : _Mem_fn_traits_base<_Res, _CV _Class, _ArgTypes...>		\
-    {									\
-      using __vararg = false_type;					\
-    };									\
-  template<typename _Res, typename _Class, typename... _ArgTypes>	\
-    struct _Mem_fn_traits<_Res (_Class::*)(_ArgTypes... ...) _CV _REF>	\
-    : _Mem_fn_traits_base<_Res, _CV _Class, _ArgTypes...>		\
-    {									\
-      using __vararg = true_type;					\
-    };
-
-#define _GLIBCXX_MEM_FN_TRAITS(_REF, _LVAL, _RVAL)		\
-  _GLIBCXX_MEM_FN_TRAITS2(		, _REF, _LVAL, _RVAL)	\
-  _GLIBCXX_MEM_FN_TRAITS2(const		, _REF, _LVAL, _RVAL)	\
-  _GLIBCXX_MEM_FN_TRAITS2(volatile	, _REF, _LVAL, _RVAL)	\
-  _GLIBCXX_MEM_FN_TRAITS2(const volatile, _REF, _LVAL, _RVAL)
-
-_GLIBCXX_MEM_FN_TRAITS( , true_type, true_type)
-_GLIBCXX_MEM_FN_TRAITS(&, true_type, false_type)
-_GLIBCXX_MEM_FN_TRAITS(&&, false_type, true_type)
-
-#if __cplusplus > 201402L
-_GLIBCXX_MEM_FN_TRAITS(noexcept, true_type, true_type)
-_GLIBCXX_MEM_FN_TRAITS(& noexcept, true_type, false_type)
-_GLIBCXX_MEM_FN_TRAITS(&& noexcept, false_type, true_type)
-#endif
-
-#undef _GLIBCXX_MEM_FN_TRAITS
-#undef _GLIBCXX_MEM_FN_TRAITS2
-
   template<typename _MemFunPtr,
 	   bool __is_mem_fn = is_member_function_pointer<_MemFunPtr>::value>
     class _Mem_fn_base

libstdc++-v3/testsuite/20_util/bind/83427.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-options "-std=gnu++17" }
+// { dg-do compile { target c++17 } }
+
+#include <functional>
+
+// PR libstdc++/83427
+
+int f() noexcept { return 0; }
+auto b = std::bind(f);
+static_assert(std::is_same_v<decltype(b)::result_type, int>);
+
+struct X { long f() const & noexcept { return 0L; } };
+auto b2 = std::bind(&X::f, X{});
+static_assert(std::is_same_v<decltype(b2)::result_type, long>);

libstdc++-v3/testsuite/20_util/bind/refqual.cc

@@ -22,8 +22,8 @@
 
 struct X
 {
-  int f() const& { return 0; }
-  int g(int i, ...)& { return i; }
+  int f() const& noexcept { return 0; }
+  int g(int i, ...)& noexcept { return i; }
 };
 
 void
@@ -34,6 +34,10 @@ test01()
   VERIFY( b() == 0 );
   auto bb = std::bind(&X::g, &x, 1, 2);
   VERIFY( bb() == 1 );
+
+  // Check for weak result types:
+  using T1 = decltype(b)::result_type;
+  using T2 = decltype(bb)::result_type;
 }
 
 int

libstdc++-v3/testsuite/20_util/reference_wrapper/83427.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-options "-std=gnu++17" }
+// { dg-do compile { target c++17 } }
+
+#include <functional>
+
+// PR libstdc++/83427
+
+int f(short) noexcept { return 0; }
+std::reference_wrapper<decltype(f)> r(f);
+static_assert(std::is_same_v<decltype(r)::result_type, int>);
+static_assert(std::is_same_v<decltype(r)::argument_type, short>);
+
+auto* p = &f;
+std::reference_wrapper<decltype(&f)> r2(p);
+static_assert(std::is_same_v<decltype(r2)::result_type, int>);
+static_assert(std::is_same_v<decltype(r2)::argument_type, short>);
+
+struct X { long f() const & noexcept { return 0L; } };
+auto m = &X::f;
+std::reference_wrapper<decltype(m)> r3(m);
+static_assert(std::is_same_v<decltype(r3)::result_type, long>);
+static_assert(std::is_same_v<decltype(r3)::argument_type, const X*>);