std::invoke wrongly takes the partial specialization for objects instead for functions for functions marked with noexcept. I'm on r331914.

#include <functional>

void func() noexcept {}

int main() { std::invoke(func); }

Here's the full error message:

In file included from main.cpp:1:
In file included from /usr/local/bin/../include/c++/v1/functional:484:
/usr/local/bin/../include/c++/v1/type_traits:4196:19: error: invalid application of 'sizeof' to a function type
    static_assert(sizeof(_Tp) > 0, Type must be complete.);
                  ^~~~~~~~~~~
/usr/local/bin/../include/c++/v1/type_traits:4201:15: note: in instantiation of template class 'std::__1::__check_complete<void () noexcept>' requested here
    : private __check_complete<_Tp>
              ^
/usr/local/bin/../include/c++/v1/type_traits:4494:15: note: in instantiation of template class 'std::__1::__check_complete<void (&)() noexcept>' requested here
    : private __check_complete<_Fp>
              ^
/usr/local/bin/../include/c++/v1/type_traits:4557:9: note: in instantiation of template class 'std::__1::__invokable_r<void, void (&)() noexcept>' requested here
        __invokable<_Fp, _Args...>::value,
        ^
/usr/local/bin/../include/c++/v1/type_traits:4566:14: note: in instantiation of template class 'std::__1::__invoke_of<void (&)() noexcept>' requested here
    : public __invoke_of<_Fp, _Args...>
             ^
/usr/local/bin/../include/c++/v1/type_traits:4571:22: note: in instantiation of template class 'std::__1::result_of<void (&())() noexcept>' requested here
template <class _Tp> using result_of_t = typename result_of<_Tp>::type;
                     ^
/usr/local/bin/../include/c++/v1/functional:2346:1: note: in instantiation of template type alias 'result_of_t' requested here
result_of_t<_Fn&&(_Args&&...)>
^
main.cpp:5:14: note: while substituting deduced template arguments into function template 'invoke' [with _Fn = void (&)() noexcept, _Args = <>]
int main() { std::invoke(func); }
             ^
1 error generated.