C++ 使用std:：bind和std:：reference\u包装器：：get
我试图使用C++ 使用std:：bind和std:：reference\u包装器：：get,c++,c++11,gcc,functional-programming,stdbind,C++,C++11,Gcc,Functional Programming,Stdbind,我试图使用std:：bind调用std:：reference\u wrapper:：get，但我无法将其编译。我确信我忽略了一些显而易见的东西，但编译器错误并没有帮我解决问题。此代码是人为设计的，并不代表我的实际用例： #include <functional> #include <iostream> struct A { void p() {std::cout << this << '\n';}; }; using ARef = st
std:：bindstd:：reference\u wrapper:：get#include <functional>
#include <iostream>
struct A
{
void p() {std::cout << this << '\n';};
};
using ARef = std::reference_wrapper< A >;
int main()
{
A a;
a.p();
auto p = std::bind (&A::p, std::placeholders::_1);
p (a); // ok
ARef ar (a);
p (ar.get()); // ok
auto get = std::bind (&ARef::get, std::placeholders::_1);
p (get (ar)); // error
}
#包括
#包括
结构A
{
void p（）{std:：cout
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/local/include/c++/6.3.0/functional:600:2：注：候选：模板decltype（std:(const std:)调用（（（const std:)Mem(u fn)base*）this）->std:(Mem fn(u base:)mu pmf，（forward）（std:)Mem fn(base:：operator（）：)操作符（）：(std:)Mem fn(base&&)operator（）)操作符（）)std:)带&&&&&)argu&&&&&&&&&const noexcept；bool__是_mem_fn=true]
运算符（）
^~~~~~~~
/usr/local/include/c++/6.3.0/functional:600:2:注意：模板参数推断/替换失败：
/usr/local/include/c++/6.3.0/functional:替换“模板decltype（std:：”uu调用（（（const std:：）u Mem_fn_base*）this）->std:：”umem_fn_base:：：”uu M_pmf，（forward）（std:：”umem_fn_base:：operator（）：：：：：：）std:”umem_{fn_base:：operator（）（&&&）const:“：”uu Mem_umem fn{fn_ubase:：operator（），”与std=”wrapper（），”std=”std=”std:“：”std:”
/usr/local/include/c++/6.3.0/功能：985:39:此处为必填项
/usr/local/include/c++/6.3.0/functional:603:27:错误：调用“u invoke（A&（std:：reference_wrapper:：*const&）（）const noexcept，std:：reference_wrapper&”）没有匹配的函数
->decltype（std:：u调用（_M_pmf，std：：转发（u参数）…）
~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/local/include/c++/6.3.0/functional:245:5:注：候选：模板typename std:：result of:：type std:：u调用（_可调用&&，_参数&&…）
__调用（_可调用&&&&&&&&&&&&…_参数）
^~~~~~~~
/usr/local/include/c++/6.3.0/functional:245:5:注意：模板参数推导/替换失败：
/usr/local/include/c++/6.3.0/functional:替换“模板typename std:：result of:：type std:：”调用（_-Callable&&，_-Args&&&…[使用_-Callable=A&（std:：reference_-wrapper:：*const&）（）const-noexcept；_-Args={std:：reference_-wrapper&}]：
/usr/local/include/c++/6.3.0/functional:603:27：替换模板decltype（std:(const std:)调用（(const std:)Mem(u fn)base*）this）->std:(Mem fn(u base:)mu pmf，（forward）（std:(Mem fn)base:：operator（）：)操作符（）：(argu Mem fn&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&
/usr/local/include/c++/6.3.0/功能：985:39:此处为必填项
/usr/local/include/c++/6.3.0/functional:245:5:错误：在“class std:：result_of”中没有名为“type”的类型
/usr/local/include/c++/6.3.0/functional:1003:2:注：候选：模板(结果std:):(绑定):(参数&&…)const[with(带)参数={(参数…}；(结果=)函数=std:(内存)fn；(绑定)参数={std:(占位符}]
运算符（）
^~~~~~~~
/usr/local/include/c++/6.3.0/functional:1003:2:注意：模板参数推断/替换失败：
/usr/local/include/c++/6.3.0/functional:999:53:错误：调用“（const std:：_Mem_fn）（std:：reference_wrapper&）”不匹配
=decltype（std:：declval:：type>（）(
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~
/usr/local/include/c++/6.3.0/functional:600:2：注：候选：模板decltype（std:(const std:)调用（（（const std:)Mem(u fn)base*）this）->std:(Mem fn(u base:)mu pmf，（forward）（std:)Mem fn(base:：operator（）：)操作符（）：(std:)Mem fn(base&&)operator（）)操作符（）)std:)带&&&&&)argu&&&&&&&&&const noexcept；bool__是_mem_fn=true]
运算符（）
^~~~~~~~
/usr/local/include/c++/6.3.0/functional:600:2:注意：模板参数推断/替换失败：
/usr/local/include/c++/6.3.0/functional:替换“模板decltype（std:：”uu调用（（（const std:：）u Mem_fn_base*）this）->std:：”umem_fn_base:：：”uu M_pmf，（forward）（std:：”umem_fn_base:：operator（）：：：：：：）std:”umem_{fn_base:：operator（）（&&&）const:“：”uu Mem_umem fn{fn_ubase:：operator（），”与std=”wrapper（），”std=”std=”std:“：”std:”
/usr/local/include/c++/6.3.0/功能：999:53:此处为必填项
/usr/local/include/c++/6.3.0/functional:603:27:错误：调用“u invoke（A&（std:：reference_wrapper:：*const&）（）const noexcept，std:：reference_wrapper&”）没有匹配的函数
->decltype（std:：u调用（_M_pmf，std：：转发（u参数）…）
~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/local/include/c++/6.3.0/functional:245:5:注：候选：模板typename std:：result of:：type std:：u调用（_可调用&&，_参数&&…）
__调用（_可调用&&&&&&&&&&&&…_参数）
^~~~~~~~
/usr/local/include/c++/6.3.0/functional:245:5:注意：模板参数推导/替换失败：
/usr/local/include/c++/6.3.0/functional:替换“模板typename std:：result of:：type std:：”调用（_-Callable&&，_-Args&&&…[使用_-Callable=A&（std:：reference_-wrapper:：*const&）（）const-noexcept；_-Args={std:：reference_-wrapper&}]：
/usr/local/include/c++/6.3.0/functional:603:27：替换模板decltype（std:(const std:)调用（(const std:)Mem(u fn)base*）this）->std:(Mem fn(u base:)mu pmf，（forward）（std:(Mem fn)base:：operator（）：)操作符（）：(argu Mem fn&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&
/usr/local/include/c++/6.3.0/功能：999:53:此处为必填项
/usr/local/include/c++/6.3.0/functional:245:5:错误：在“class std:：result_of”中没有名为“type”的类型
/usr/local/include/c++/6.3.0/functional:1017:2：注：候选：模板(结果std:):(绑定)(Args&&&…)volatile[with(带)Args={(Args…}；(结果=)结果=(函数=std:):(内存)fn；(绑定)Args={占位符}]
运算符（）
^~~~~~~~
/usr/local/include/c++/6.3.0/functional:1017:2:注意：模板参数推导/替换失败：
/usr/local/include/c++/6.3.0/functional:1013:70：
main.cpp: In function 'int main()':
main.cpp:21:19: error: no match for call to '(std::_Bind<std::_Mem_fn<A& (std::reference_wrapper<A>::*)() const noexcept>(std::_Placeholder<1>)>) (ARef&)'
p (get (ar)); // error
^
In file included from main.cpp:1:0:
/usr/local/include/c++/6.3.0/functional:989:2: note: candidate: template<class ... _Args, class _Result> _Result std::_Bind<_Functor(_Bound_args ...)>::operator()(_Args&& ...) [with _Args = {_Args ...}; _Result = _Result; _Functor = std::_Mem_fn<A& (std::reference_wrapper<A>::*)() const noexcept>; _Bound_args = {std::_Placeholder<1>}]
operator()(_Args&&... __args)
^~~~~~~~
/usr/local/include/c++/6.3.0/functional:989:2: note: template argument deduction/substitution failed:
/usr/local/include/c++/6.3.0/functional:985:39: error: no match for call to '(std::_Mem_fn<A& (std::reference_wrapper<A>::*)() const noexcept>) (std::reference_wrapper<A>&)'
= decltype( std::declval<_Functor&>()(
~~~~~~~~~~~~~~~~~~~~~~~~~^
_Mu<_Bound_args>()( std::declval<_Bound_args&>(),
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
std::declval<tuple<_Args...>&>() )... ) )>
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/local/include/c++/6.3.0/functional:600:2: note: candidate: template<class ... _Args> decltype (std::__invoke(((const std::_Mem_fn_base<_MemFunPtr, __is_mem_fn>*)this)->std::_Mem_fn_base<_MemFunPtr, __is_mem_fn>::_M_pmf, (forward<_Args>)(std::_Mem_fn_base::operator()::__args)...)) std::_Mem_fn_base<_MemFunPtr, __is_mem_fn>::operator()(_Args&& ...) const [with _Args = {_Args ...}; _MemFunPtr = A& (std::reference_wrapper<A>::*)() const noexcept; bool __is_mem_fn = true]
operator()(_Args&&... __args) const
^~~~~~~~
/usr/local/include/c++/6.3.0/functional:600:2: note: template argument deduction/substitution failed:
/usr/local/include/c++/6.3.0/functional: In substitution of 'template<class ... _Args> decltype (std::__invoke(((const std::_Mem_fn_base<_MemFunPtr, __is_mem_fn>*)this)->std::_Mem_fn_base<_MemFunPtr, __is_mem_fn>::_M_pmf, (forward<_Args>)(std::_Mem_fn_base::operator()::__args)...)) std::_Mem_fn_base<_MemFunPtr, __is_mem_fn>::operator()(_Args&& ...) const [with _Args = {std::reference_wrapper<A>&}]':
/usr/local/include/c++/6.3.0/functional:985:39: required from here
/usr/local/include/c++/6.3.0/functional:603:27: error: no matching function for call to '__invoke(A& (std::reference_wrapper<A>::* const&)() const noexcept, std::reference_wrapper<A>&)'
-> decltype(std::__invoke(_M_pmf, std::forward<_Args>(__args)...))
~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/local/include/c++/6.3.0/functional:245:5: note: candidate: template<class _Callable, class ... _Args> typename std::result_of<_Callable&&(_Args&& ...)>::type std::__invoke(_Callable&&, _Args&& ...)
__invoke(_Callable&& __fn, _Args&&... __args)
^~~~~~~~
/usr/local/include/c++/6.3.0/functional:245:5: note: template argument deduction/substitution failed:
/usr/local/include/c++/6.3.0/functional: In substitution of 'template<class _Callable, class ... _Args> typename std::result_of<_Callable&&(_Args&& ...)>::type std::__invoke(_Callable&&, _Args&& ...) [with _Callable = A& (std::reference_wrapper<A>::* const&)() const noexcept; _Args = {std::reference_wrapper<A>&}]':
/usr/local/include/c++/6.3.0/functional:603:27: required by substitution of 'template<class ... _Args> decltype (std::__invoke(((const std::_Mem_fn_base<_MemFunPtr, __is_mem_fn>*)this)->std::_Mem_fn_base<_MemFunPtr, __is_mem_fn>::_M_pmf, (forward<_Args>)(std::_Mem_fn_base::operator()::__args)...)) std::_Mem_fn_base<_MemFunPtr, __is_mem_fn>::operator()(_Args&& ...) const [with _Args = {std::reference_wrapper<A>&}]'
/usr/local/include/c++/6.3.0/functional:985:39: required from here
/usr/local/include/c++/6.3.0/functional:245:5: error: no type named 'type' in 'class std::result_of<A& (std::reference_wrapper<A>::* const&(std::reference_wrapper<A>&))() const noexcept>'
/usr/local/include/c++/6.3.0/functional:1003:2: note: candidate: template<class ... _Args, class _Result> _Result std::_Bind<_Functor(_Bound_args ...)>::operator()(_Args&& ...) const [with _Args = {_Args ...}; _Result = _Result; _Functor = std::_Mem_fn<A& (std::reference_wrapper<A>::*)() const noexcept>; _Bound_args = {std::_Placeholder<1>}]
operator()(_Args&&... __args) const
^~~~~~~~
/usr/local/include/c++/6.3.0/functional:1003:2: note: template argument deduction/substitution failed:
/usr/local/include/c++/6.3.0/functional:999:53: error: no match for call to '(const std::_Mem_fn<A& (std::reference_wrapper<A>::*)() const noexcept>) (std::reference_wrapper<A>&)'
= decltype( std::declval<typename enable_if<(sizeof...(_Args) >= 0),
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
typename add_const<_Functor>::type&>::type>()(
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~
/usr/local/include/c++/6.3.0/functional:600:2: note: candidate: template<class ... _Args> decltype (std::__invoke(((const std::_Mem_fn_base<_MemFunPtr, __is_mem_fn>*)this)->std::_Mem_fn_base<_MemFunPtr, __is_mem_fn>::_M_pmf, (forward<_Args>)(std::_Mem_fn_base::operator()::__args)...)) std::_Mem_fn_base<_MemFunPtr, __is_mem_fn>::operator()(_Args&& ...) const [with _Args = {_Args ...}; _MemFunPtr = A& (std::reference_wrapper<A>::*)() const noexcept; bool __is_mem_fn = true]
operator()(_Args&&... __args) const
^~~~~~~~
/usr/local/include/c++/6.3.0/functional:600:2: note: template argument deduction/substitution failed:
/usr/local/include/c++/6.3.0/functional: In substitution of 'template<class ... _Args> decltype (std::__invoke(((const std::_Mem_fn_base<_MemFunPtr, __is_mem_fn>*)this)->std::_Mem_fn_base<_MemFunPtr, __is_mem_fn>::_M_pmf, (forward<_Args>)(std::_Mem_fn_base::operator()::__args)...)) std::_Mem_fn_base<_MemFunPtr, __is_mem_fn>::operator()(_Args&& ...) const [with _Args = {std::reference_wrapper<A>&}]':
/usr/local/include/c++/6.3.0/functional:999:53: required from here
/usr/local/include/c++/6.3.0/functional:603:27: error: no matching function for call to '__invoke(A& (std::reference_wrapper<A>::* const&)() const noexcept, std::reference_wrapper<A>&)'
-> decltype(std::__invoke(_M_pmf, std::forward<_Args>(__args)...))
~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/local/include/c++/6.3.0/functional:245:5: note: candidate: template<class _Callable, class ... _Args> typename std::result_of<_Callable&&(_Args&& ...)>::type std::__invoke(_Callable&&, _Args&& ...)
__invoke(_Callable&& __fn, _Args&&... __args)
^~~~~~~~
/usr/local/include/c++/6.3.0/functional:245:5: note: template argument deduction/substitution failed:
/usr/local/include/c++/6.3.0/functional: In substitution of 'template<class _Callable, class ... _Args> typename std::result_of<_Callable&&(_Args&& ...)>::type std::__invoke(_Callable&&, _Args&& ...) [with _Callable = A& (std::reference_wrapper<A>::* const&)() const noexcept; _Args = {std::reference_wrapper<A>&}]':
/usr/local/include/c++/6.3.0/functional:603:27: required by substitution of 'template<class ... _Args> decltype (std::__invoke(((const std::_Mem_fn_base<_MemFunPtr, __is_mem_fn>*)this)->std::_Mem_fn_base<_MemFunPtr, __is_mem_fn>::_M_pmf, (forward<_Args>)(std::_Mem_fn_base::operator()::__args)...)) std::_Mem_fn_base<_MemFunPtr, __is_mem_fn>::operator()(_Args&& ...) const [with _Args = {std::reference_wrapper<A>&}]'
/usr/local/include/c++/6.3.0/functional:999:53: required from here
/usr/local/include/c++/6.3.0/functional:245:5: error: no type named 'type' in 'class std::result_of<A& (std::reference_wrapper<A>::* const&(std::reference_wrapper<A>&))() const noexcept>'
/usr/local/include/c++/6.3.0/functional:1017:2: note: candidate: template<class ... _Args, class _Result> _Result std::_Bind<_Functor(_Bound_args ...)>::operator()(_Args&& ...) volatile [with _Args = {_Args ...}; _Result = _Result; _Functor = std::_Mem_fn<A& (std::reference_wrapper<A>::*)() const noexcept>; _Bound_args = {std::_Placeholder<1>}]
operator()(_Args&&... __args) volatile
^~~~~~~~
/usr/local/include/c++/6.3.0/functional:1017:2: note: template argument deduction/substitution failed:
/usr/local/include/c++/6.3.0/functional:1013:70: error: no match for call to '(volatile std::_Mem_fn<A& (std::reference_wrapper<A>::*)() const noexcept>) (std::reference_wrapper<A>&)'
= decltype( std::declval<typename enable_if<(sizeof...(_Args) >= 0),
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
typename add_volatile<_Functor>::type&>::type>()(
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~
/usr/local/include/c++/6.3.0/functional:600:2: note: candidate: template<class ... _Args> decltype (std::__invoke(((const std::_Mem_fn_base<_MemFunPtr, __is_mem_fn>*)this)->std::_Mem_fn_base<_MemFunPtr, __is_mem_fn>::_M_pmf, (forward<_Args>)(std::_Mem_fn_base::operator()::__args)...)) std::_Mem_fn_base<_MemFunPtr, __is_mem_fn>::operator()(_Args&& ...) const [with _Args = {_Args ...}; _MemFunPtr = A& (std::reference_wrapper<A>::*)() const noexcept; bool __is_mem_fn = true]
operator()(_Args&&... __args) const
^~~~~~~~
/usr/local/include/c++/6.3.0/functional:600:2: note: template argument deduction/substitution failed:
/usr/local/include/c++/6.3.0/functional: In substitution of 'template<class ... _Args> decltype (std::__invoke(((const std::_Mem_fn_base<_MemFunPtr, __is_mem_fn>*)this)->std::_Mem_fn_base<_MemFunPtr, __is_mem_fn>::_M_pmf, (forward<_Args>)(std::_Mem_fn_base::operator()::__args)...)) std::_Mem_fn_base<_MemFunPtr, __is_mem_fn>::operator()(_Args&& ...) const [with _Args = {std::reference_wrapper<A>&}]':
/usr/local/include/c++/6.3.0/functional:1013:70: required from here
/usr/local/include/c++/6.3.0/functional:603:27: error: no matching function for call to '__invoke(A& (std::reference_wrapper<A>::* const&)() const noexcept, std::reference_wrapper<A>&)'
-> decltype(std::__invoke(_M_pmf, std::forward<_Args>(__args)...))
~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/local/include/c++/6.3.0/functional:245:5: note: candidate: template<class _Callable, class ... _Args> typename std::result_of<_Callable&&(_Args&& ...)>::type std::__invoke(_Callable&&, _Args&& ...)
__invoke(_Callable&& __fn, _Args&&... __args)
^~~~~~~~
/usr/local/include/c++/6.3.0/functional:245:5: note: template argument deduction/substitution failed:
/usr/local/include/c++/6.3.0/functional: In substitution of 'template<class _Callable, class ... _Args> typename std::result_of<_Callable&&(_Args&& ...)>::type std::__invoke(_Callable&&, _Args&& ...) [with _Callable = A& (std::reference_wrapper<A>::* const&)() const noexcept; _Args = {std::reference_wrapper<A>&}]':
/usr/local/include/c++/6.3.0/functional:603:27: required by substitution of 'template<class ... _Args> decltype (std::__invoke(((const std::_Mem_fn_base<_MemFunPtr, __is_mem_fn>*)this)->std::_Mem_fn_base<_MemFunPtr, __is_mem_fn>::_M_pmf, (forward<_Args>)(std::_Mem_fn_base::operator()::__args)...)) std::_Mem_fn_base<_MemFunPtr, __is_mem_fn>::operator()(_Args&& ...) const [with _Args = {std::reference_wrapper<A>&}]'
/usr/local/include/c++/6.3.0/functional:1013:70: required from here
/usr/local/include/c++/6.3.0/functional:245:5: error: no type named 'type' in 'class std::result_of<A& (std::reference_wrapper<A>::* const&(std::reference_wrapper<A>&))() const noexcept>'
/usr/local/include/c++/6.3.0/functional:1031:2: note: candidate: template<class ... _Args, class _Result> _Result std::_Bind<_Functor(_Bound_args ...)>::operator()(_Args&& ...) const volatile [with _Args = {_Args ...}; _Result = _Result; _Functor = std::_Mem_fn<A& (std::reference_wrapper<A>::*)() const noexcept>; _Bound_args = {std::_Placeholder<1>}]
operator()(_Args&&... __args) const volatile
^~~~~~~~
/usr/local/include/c++/6.3.0/functional:1031:2: note: template argument deduction/substitution failed:
/usr/local/include/c++/6.3.0/functional:1027:64: error: no match for call to '(const volatile std::_Mem_fn<A& (std::reference_wrapper<A>::*)() const noexcept>) (std::reference_wrapper<A>&)'
= decltype( std::declval<typename enable_if<(sizeof...(_Args) >= 0),
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
typename add_cv<_Functor>::type&>::type>()(
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~
/usr/local/include/c++/6.3.0/functional:600:2: note: candidate: template<class ... _Args> decltype (std::__invoke(((const std::_Mem_fn_base<_MemFunPtr, __is_mem_fn>*)this)->std::_Mem_fn_base<_MemFunPtr, __is_mem_fn>::_M_pmf, (forward<_Args>)(std::_Mem_fn_base::operator()::__args)...)) std::_Mem_fn_base<_MemFunPtr, __is_mem_fn>::operator()(_Args&& ...) const [with _Args = {_Args ...}; _MemFunPtr = A& (std::reference_wrapper<A>::*)() const noexcept; bool __is_mem_fn = true]
operator()(_Args&&... __args) const
^~~~~~~~
/usr/local/include/c++/6.3.0/functional:600:2: note: template argument deduction/substitution failed:
/usr/local/include/c++/6.3.0/functional: In substitution of 'template<class ... _Args> decltype (std::__invoke(((const std::_Mem_fn_base<_MemFunPtr, __is_mem_fn>*)this)->std::_Mem_fn_base<_MemFunPtr, __is_mem_fn>::_M_pmf, (forward<_Args>)(std::_Mem_fn_base::operator()::__args)...)) std::_Mem_fn_base<_MemFunPtr, __is_mem_fn>::operator()(_Args&& ...) const [with _Args = {std::reference_wrapper<A>&}]':
/usr/local/include/c++/6.3.0/functional:1027:64: required from here
/usr/local/include/c++/6.3.0/functional:603:27: error: no matching function for call to '__invoke(A& (std::reference_wrapper<A>::* const&)() const noexcept, std::reference_wrapper<A>&)'
-> decltype(std::__invoke(_M_pmf, std::forward<_Args>(__args)...))
~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/local/include/c++/6.3.0/functional:245:5: note: candidate: template<class _Callable, class ... _Args> typename std::result_of<_Callable&&(_Args&& ...)>::type std::__invoke(_Callable&&, _Args&& ...)
__invoke(_Callable&& __fn, _Args&&... __args)
^~~~~~~~
/usr/local/include/c++/6.3.0/functional:245:5: note: template argument deduction/substitution failed:
/usr/local/include/c++/6.3.0/functional: In substitution of 'template<class _Callable, class ... _Args> typename std::result_of<_Callable&&(_Args&& ...)>::type std::__invoke(_Callable&&, _Args&& ...) [with _Callable = A& (std::reference_wrapper<A>::* const&)() const noexcept; _Args = {std::reference_wrapper<A>&}]':
/usr/local/include/c++/6.3.0/functional:603:27: required by substitution of 'template<class ... _Args> decltype (std::__invoke(((const std::_Mem_fn_base<_MemFunPtr, __is_mem_fn>*)this)->std::_Mem_fn_base<_MemFunPtr, __is_mem_fn>::_M_pmf, (forward<_Args>)(std::_Mem_fn_base::operator()::__args)...)) std::_Mem_fn_base<_MemFunPtr, __is_mem_fn>::operator()(_Args&& ...) const [with _Args = {std::reference_wrapper<A>&}]'
/usr/local/include/c++/6.3.0/functional:1027:64: required from here
/usr/local/include/c++/6.3.0/functional:245:5: error: no type named 'type' in 'class std::result_of<A& (std::reference_wrapper<A>::* const&(std::reference_wrapper<A>&))() const noexcept>'