* include/std/functional (_Mem_fn): Constrain function call operators

	to avoid ambiguities. Use perfect forwarding.
	* testsuite/20_util/function_objects/mem_fn/55463.cc: Additional
	tests.
	* testsuite/20_util/function_objects/mem_fn/forward.cc: New.
	* testsuite/20_util/bind/ref_neg.cc: Adjust dg-error line numbers.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@193879 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 201 insertions, 76 deletions

diff --git a/libstdc++-v3/include/std/functional b/libstdc++-v3/include/std/functional
index 0d8fbd6bdae..604481b20c4 100644
--- a/libstdc++-v3/include/std/functional
+++ b/libstdc++-v3/include/std/functional
@@ -501,6 +501,26 @@ _GLIBCXX_HAS_NESTED_TYPE(result_type)
 
   // @} group functors
 
+  template<typename... _Cond>
+    using _Require = typename enable_if<__and_<_Cond...>::value>::type;
+
+  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>>;
+
   /**
    * Derives from @c unary_function or @c binary_function, or perhaps
    * nothing, depending on the number of arguments provided. The
@@ -526,19 +546,38 @@ _GLIBCXX_HAS_NESTED_TYPE(result_type)
     {
       typedef _Res (_Class::*_Functor)(_ArgTypes...);
 
-      template<typename _Tp>
+      template<typename _Tp, typename... _Args>
 	_Res
 	_M_call(_Tp&& __object, const volatile _Class *,
-		_ArgTypes... __args) const
+		_Args&&... __args) const
 	{
 	  return (std::forward<_Tp>(__object).*__pmf)
-	    (std::forward<_ArgTypes>(__args)...);
+	    (std::forward<_Args>(__args)...);
 	}
 
-      template<typename _Tp>
+      template<typename _Tp, typename... _Args>
 	_Res
-	_M_call(_Tp&& __ptr, const volatile void *, _ArgTypes... __args) const
-	{ return ((*__ptr).*__pmf)(std::forward<_ArgTypes>(__args)...); }
+	_M_call(_Tp&& __ptr, const volatile void *, _Args&&... __args) const
+	{ return ((*__ptr).*__pmf)(std::forward<_Args>(__args)...); }
+
+      // Require each _Args to be convertible to corresponding _ArgTypes
+      template<typename... _Args>
+	using _RequireValidArgs
+	  = _Require<_AllConvertible<_Pack<_Args...>, _Pack<_ArgTypes...>>>;
+
+      // Require each _Args to be convertible to corresponding _ArgTypes
+      // and require _Tp is not _Class, _Class& or _Class*
+      template<typename _Tp, typename... _Args>
+	using _RequireValidArgs2
+	  = _Require<_NotSame<_Class, _Tp>, _NotSame<_Class*, _Tp>,
+		     _AllConvertible<_Pack<_Args...>, _Pack<_ArgTypes...>>>;
+
+      // Require each _Args to be convertible to corresponding _ArgTypes
+      // and require _Tp is _Class or derived from _Class
+      template<typename _Tp, typename... _Args>
+	using _RequireValidArgs3
+	  = _Require<is_base_of<_Class, _Tp>,
+		     _AllConvertible<_Pack<_Args...>, _Pack<_ArgTypes...>>>;
 
     public:
       typedef _Res result_type;
@@ -546,28 +585,39 @@ _GLIBCXX_HAS_NESTED_TYPE(result_type)
       explicit _Mem_fn(_Functor __pmf) : __pmf(__pmf) { }
 
       // Handle objects
-      _Res
-      operator()(_Class& __object, _ArgTypes... __args) const
-      { return (__object.*__pmf)(std::forward<_ArgTypes>(__args)...); }
+      template<typename... _Args, typename _Req = _RequireValidArgs<_Args...>>
+	_Res
+	operator()(_Class& __object, _Args&&... __args) const
+	{ return (__object.*__pmf)(std::forward<_Args>(__args)...); }
+
+      template<typename... _Args, typename _Req = _RequireValidArgs<_Args...>>
+	_Res
+	operator()(_Class&& __object, _Args&&... __args) const
+	{
+	  return (std::move(__object).*__pmf)(std::forward<_Args>(__args)...);
+	}
 
       // Handle pointers
-      _Res
-      operator()(_Class* __object, _ArgTypes... __args) const
-      { return (__object->*__pmf)(std::forward<_ArgTypes>(__args)...); }
+      template<typename... _Args, typename _Req = _RequireValidArgs<_Args...>>
+	_Res
+	operator()(_Class* __object, _Args&&... __args) const
+	{ return (__object->*__pmf)(std::forward<_Args>(__args)...); }
 
       // Handle smart pointers, references and pointers to derived
-      template<typename _Tp>
+      template<typename _Tp, typename... _Args,
+	       typename _Req = _RequireValidArgs2<_Tp, _Args...>>
 	_Res
-	operator()(_Tp&& __object, _ArgTypes... __args) const
+	operator()(_Tp&& __object, _Args&&... __args) const
 	{
 	  return _M_call(std::forward<_Tp>(__object), &__object,
-	      std::forward<_ArgTypes>(__args)...);
+	      std::forward<_Args>(__args)...);
 	}
 
-      template<typename _Tp>
+      template<typename _Tp, typename... _Args,
+	       typename _Req = _RequireValidArgs3<_Tp, _Args...>>
 	_Res
-	operator()(reference_wrapper<_Tp> __ref, _ArgTypes... __args) const
-	{ return operator()(__ref.get(), std::forward<_ArgTypes>(__args)...); }
+	operator()(reference_wrapper<_Tp> __ref, _Args&&... __args) const
+	{ return operator()(__ref.get(), std::forward<_Args>(__args)...); }
 
     private:
       _Functor __pmf;
@@ -581,19 +631,33 @@ _GLIBCXX_HAS_NESTED_TYPE(result_type)
     {
       typedef _Res (_Class::*_Functor)(_ArgTypes...) const;
 
-      template<typename _Tp>
+      template<typename _Tp, typename... _Args>
 	_Res
 	_M_call(_Tp&& __object, const volatile _Class *,
-		_ArgTypes... __args) const
+		_Args&&... __args) const
 	{
 	  return (std::forward<_Tp>(__object).*__pmf)
-	    (std::forward<_ArgTypes>(__args)...);
+	    (std::forward<_Args>(__args)...);
 	}
 
-      template<typename _Tp>
+      template<typename _Tp, typename... _Args>
 	_Res
-	_M_call(_Tp&& __ptr, const volatile void *, _ArgTypes... __args) const
-	{ return ((*__ptr).*__pmf)(std::forward<_ArgTypes>(__args)...); }
+	_M_call(_Tp&& __ptr, const volatile void *, _Args&&... __args) const
+	{ return ((*__ptr).*__pmf)(std::forward<_Args>(__args)...); }
+
+      template<typename... _Args>
+	using _RequireValidArgs
+	  = _Require<_AllConvertible<_Pack<_Args...>, _Pack<_ArgTypes...>>>;
+
+      template<typename _Tp, typename... _Args>
+	using _RequireValidArgs2
+	  = _Require<_NotSame<_Class, _Tp>, _NotSame<_Class*, _Tp>,
+		     _AllConvertible<_Pack<_Args...>, _Pack<_ArgTypes...>>>;
+
+      template<typename _Tp, typename... _Args>
+	using _RequireValidArgs3
+	  = _Require<is_base_of<_Class, _Tp>,
+		     _AllConvertible<_Pack<_Args...>, _Pack<_ArgTypes...>>>;
 
     public:
       typedef _Res result_type;
@@ -601,27 +665,38 @@ _GLIBCXX_HAS_NESTED_TYPE(result_type)
       explicit _Mem_fn(_Functor __pmf) : __pmf(__pmf) { }
 
       // Handle objects
-      _Res
-      operator()(const _Class& __object, _ArgTypes... __args) const
-      { return (__object.*__pmf)(std::forward<_ArgTypes>(__args)...); }
+      template<typename... _Args, typename _Req = _RequireValidArgs<_Args...>>
+	_Res
+	operator()(const _Class& __object, _Args&&... __args) const
+	{ return (__object.*__pmf)(std::forward<_Args>(__args)...); }
+
+      template<typename... _Args, typename _Req = _RequireValidArgs<_Args...>>
+	_Res
+	operator()(const _Class&& __object, _Args&&... __args) const
+	{
+	  return (std::move(__object).*__pmf)(std::forward<_Args>(__args)...);
+	}
 
       // Handle pointers
-      _Res
-      operator()(const _Class* __object, _ArgTypes... __args) const
-      { return (__object->*__pmf)(std::forward<_ArgTypes>(__args)...); }
+      template<typename... _Args, typename _Req = _RequireValidArgs<_Args...>>
+	_Res
+	operator()(const _Class* __object, _Args&&... __args) const
+	{ return (__object->*__pmf)(std::forward<_Args>(__args)...); }
 
       // Handle smart pointers, references and pointers to derived
-      template<typename _Tp>
-	_Res operator()(_Tp&& __object, _ArgTypes... __args) const
+      template<typename _Tp, typename... _Args,
+	       typename _Req = _RequireValidArgs2<_Tp, _Args...>>
+	_Res operator()(_Tp&& __object, _Args&&... __args) const
 	{
 	  return _M_call(std::forward<_Tp>(__object), &__object,
-	      std::forward<_ArgTypes>(__args)...);
+	      std::forward<_Args>(__args)...);
 	}
 
-      template<typename _Tp>
+      template<typename _Tp, typename... _Args,
+	       typename _Req = _RequireValidArgs3<_Tp, _Args...>>
 	_Res
-	operator()(reference_wrapper<_Tp> __ref, _ArgTypes... __args) const
-	{ return operator()(__ref.get(), std::forward<_ArgTypes>(__args)...); }
+	operator()(reference_wrapper<_Tp> __ref, _Args&&... __args) const
+	{ return operator()(__ref.get(), std::forward<_Args>(__args)...); }
 
     private:
       _Functor __pmf;
@@ -635,19 +710,33 @@ _GLIBCXX_HAS_NESTED_TYPE(result_type)
     {
       typedef _Res (_Class::*_Functor)(_ArgTypes...) volatile;
 
-      template<typename _Tp>
+      template<typename _Tp, typename... _Args>
 	_Res
 	_M_call(_Tp&& __object, const volatile _Class *,
-		_ArgTypes... __args) const
+		_Args&&... __args) const
 	{
 	  return (std::forward<_Tp>(__object).*__pmf)
-	    (std::forward<_ArgTypes>(__args)...);
+	    (std::forward<_Args>(__args)...);
 	}
 
-      template<typename _Tp>
+      template<typename _Tp, typename... _Args>
 	_Res
-	_M_call(_Tp&& __ptr, const volatile void *, _ArgTypes... __args) const
-	{ return ((*__ptr).*__pmf)(std::forward<_ArgTypes>(__args)...); }
+	_M_call(_Tp&& __ptr, const volatile void *, _Args&&... __args) const
+	{ return ((*__ptr).*__pmf)(std::forward<_Args>(__args)...); }
+
+      template<typename... _Args>
+	using _RequireValidArgs
+	  = _Require<_AllConvertible<_Pack<_Args...>, _Pack<_ArgTypes...>>>;
+
+      template<typename _Tp, typename... _Args>
+	using _RequireValidArgs2
+	  = _Require<_NotSame<_Class, _Tp>, _NotSame<_Class*, _Tp>,
+		     _AllConvertible<_Pack<_Args...>, _Pack<_ArgTypes...>>>;
+
+      template<typename _Tp, typename... _Args>
+	using _RequireValidArgs3
+	  = _Require<is_base_of<_Class, _Tp>,
+		     _AllConvertible<_Pack<_Args...>, _Pack<_ArgTypes...>>>;
 
     public:
       typedef _Res result_type;
@@ -655,28 +744,39 @@ _GLIBCXX_HAS_NESTED_TYPE(result_type)
       explicit _Mem_fn(_Functor __pmf) : __pmf(__pmf) { }
 
       // Handle objects
-      _Res
-      operator()(volatile _Class& __object, _ArgTypes... __args) const
-      { return (__object.*__pmf)(std::forward<_ArgTypes>(__args)...); }
+      template<typename... _Args, typename _Req = _RequireValidArgs<_Args...>>
+	_Res
+	operator()(volatile _Class& __object, _Args&&... __args) const
+	{ return (__object.*__pmf)(std::forward<_Args>(__args)...); }
+
+      template<typename... _Args, typename _Req = _RequireValidArgs<_Args...>>
+	_Res
+	operator()(volatile _Class&& __object, _Args&&... __args) const
+	{
+	  return (std::move(__object).*__pmf)(std::forward<_Args>(__args)...);
+	}
 
       // Handle pointers
-      _Res
-      operator()(volatile _Class* __object, _ArgTypes... __args) const
-      { return (__object->*__pmf)(std::forward<_ArgTypes>(__args)...); }
+      template<typename... _Args, typename _Req = _RequireValidArgs<_Args...>>
+	_Res
+	operator()(volatile _Class* __object, _Args&&... __args) const
+	{ return (__object->*__pmf)(std::forward<_Args>(__args)...); }
 
       // Handle smart pointers, references and pointers to derived
-      template<typename _Tp>
+      template<typename _Tp, typename... _Args,
+	       typename _Req = _RequireValidArgs2<_Tp, _Args...>>
 	_Res
-	operator()(_Tp&& __object, _ArgTypes... __args) const
+	operator()(_Tp&& __object, _Args&&... __args) const
 	{
 	  return _M_call(std::forward<_Tp>(__object), &__object,
-	      std::forward<_ArgTypes>(__args)...);
+	      std::forward<_Args>(__args)...);
 	}
 
-      template<typename _Tp>
+      template<typename _Tp, typename... _Args,
+	       typename _Req = _RequireValidArgs3<_Tp, _Args...>>
 	_Res
-	operator()(reference_wrapper<_Tp> __ref, _ArgTypes... __args) const
-	{ return operator()(__ref.get(), std::forward<_ArgTypes>(__args)...); }
+	operator()(reference_wrapper<_Tp> __ref, _Args&&... __args) const
+	{ return operator()(__ref.get(), std::forward<_Args>(__args)...); }
 
     private:
       _Functor __pmf;
@@ -690,19 +790,33 @@ _GLIBCXX_HAS_NESTED_TYPE(result_type)
     {
       typedef _Res (_Class::*_Functor)(_ArgTypes...) const volatile;
 
-      template<typename _Tp>
+      template<typename _Tp, typename... _Args>
 	_Res
 	_M_call(_Tp&& __object, const volatile _Class *,
-		_ArgTypes... __args) const
+		_Args&&... __args) const
 	{
 	  return (std::forward<_Tp>(__object).*__pmf)
-	    (std::forward<_ArgTypes>(__args)...);
+	    (std::forward<_Args>(__args)...);
 	}
 
-      template<typename _Tp>
+      template<typename _Tp, typename... _Args>
 	_Res
-	_M_call(_Tp&& __ptr, const volatile void *, _ArgTypes... __args) const
-	{ return ((*__ptr).*__pmf)(std::forward<_ArgTypes>(__args)...); }
+	_M_call(_Tp&& __ptr, const volatile void *, _Args&&... __args) const
+	{ return ((*__ptr).*__pmf)(std::forward<_Args>(__args)...); }
+
+      template<typename... _Args>
+	using _RequireValidArgs
+	  = _Require<_AllConvertible<_Pack<_Args...>, _Pack<_ArgTypes...>>>;
+
+      template<typename _Tp, typename... _Args>
+	using _RequireValidArgs2
+	  = _Require<_NotSame<_Class, _Tp>, _NotSame<_Class*, _Tp>,
+		     _AllConvertible<_Pack<_Args...>, _Pack<_ArgTypes...>>>;
+
+      template<typename _Tp, typename... _Args>
+	using _RequireValidArgs3
+	  = _Require<is_base_of<_Class, _Tp>,
+		     _AllConvertible<_Pack<_Args...>, _Pack<_ArgTypes...>>>;
 
     public:
       typedef _Res result_type;
@@ -710,27 +824,38 @@ _GLIBCXX_HAS_NESTED_TYPE(result_type)
       explicit _Mem_fn(_Functor __pmf) : __pmf(__pmf) { }
 
       // Handle objects
-      _Res
-      operator()(const volatile _Class& __object, _ArgTypes... __args) const
-      { return (__object.*__pmf)(std::forward<_ArgTypes>(__args)...); }
+      template<typename... _Args, typename _Req = _RequireValidArgs<_Args...>>
+	_Res
+	operator()(const volatile _Class& __object, _Args&&... __args) const
+	{ return (__object.*__pmf)(std::forward<_Args>(__args)...); }
+
+      template<typename... _Args, typename _Req = _RequireValidArgs<_Args...>>
+	_Res
+	operator()(const volatile _Class&& __object, _Args&&... __args) const
+	{
+	  return (std::move(__object).*__pmf)(std::forward<_Args>(__args)...);
+	}
 
       // Handle pointers
-      _Res
-      operator()(const volatile _Class* __object, _ArgTypes... __args) const
-      { return (__object->*__pmf)(std::forward<_ArgTypes>(__args)...); }
+      template<typename... _Args, typename _Req = _RequireValidArgs<_Args...>>
+	_Res
+	operator()(const volatile _Class* __object, _Args&&... __args) const
+	{ return (__object->*__pmf)(std::forward<_Args>(__args)...); }
 
       // Handle smart pointers, references and pointers to derived
-      template<typename _Tp>
-	_Res operator()(_Tp&& __object, _ArgTypes... __args) const
+      template<typename _Tp, typename... _Args,
+	       typename _Req = _RequireValidArgs2<_Tp, _Args...>>
+	_Res operator()(_Tp&& __object, _Args&&... __args) const
 	{
 	  return _M_call(std::forward<_Tp>(__object), &__object,
-	      std::forward<_ArgTypes>(__args)...);
+	      std::forward<_Args>(__args)...);
 	}
 
-      template<typename _Tp>
+      template<typename _Tp, typename... _Args,
+	       typename _Req = _RequireValidArgs3<_Tp, _Args...>>
 	_Res
-	operator()(reference_wrapper<_Tp> __ref, _ArgTypes... __args) const
-	{ return operator()(__ref.get(), std::forward<_ArgTypes>(__args)...); }
+	operator()(reference_wrapper<_Tp> __ref, _Args&&... __args) const
+	{ return operator()(__ref.get(), std::forward<_Args>(__args)...); }
 
     private:
       _Functor __pmf;
@@ -756,7 +881,7 @@ _GLIBCXX_HAS_NESTED_TYPE(result_type)
 
       // This bit of genius is due to Peter Dimov, improved slightly by
       // Douglas Gregor.
-      // Made less elegant by Jonathan Wakely to support perfect forwarding.
+      // Made less elegant to support perfect forwarding and noexcept.
       template<typename _Tp>
 	auto
 	_M_call(_Tp&& __object, const _Class *) const noexcept
@@ -807,7 +932,7 @@ _GLIBCXX_HAS_NESTED_TYPE(result_type)
       { return __object->*__pm; }
 
       // Handle smart pointers and derived
-      template<typename _Tp>
+      template<typename _Tp, typename _Req = _Require<_NotSame<_Class*, _Tp>>>
 	auto
 	operator()(_Tp&& __unknown) const
 	noexcept(noexcept(std::declval<_Mem_fn*>()->_M_call
@@ -815,12 +940,12 @@ _GLIBCXX_HAS_NESTED_TYPE(result_type)
 	-> decltype(this->_M_call(std::forward<_Tp>(__unknown), &__unknown))
 	{ return _M_call(std::forward<_Tp>(__unknown), &__unknown); }
 
-      template<typename _Tp>
+      template<typename _Tp, typename _Req = _Require<is_base_of<_Class, _Tp>>>
 	auto
 	operator()(reference_wrapper<_Tp> __ref) const
 	noexcept(noexcept(std::declval<_Mem_fn&>()(__ref.get())))
 	-> decltype((*this)(__ref.get()))
-	{ return operator()(__ref.get()); }
+	{ return (*this)(__ref.get()); }
 
     private:
       _Res _Class::*__pm;