Make zug::compat::invoke work with pointer-to-member function

[tusooa]

arximboldi/lager#199

[arximboldi]

LGTM even though it would be nice to have tests that cover the 4 overload cases (it seems to me some are not covered here potentially). Either way thanks a lot for the contribution!

[arximboldi]

Uhhh... tests are failing. Could you maybe look into why?

[tusooa]

Uhhh... tests are failing. Could you maybe look into why?

I can't reproduce this locally using GCC 13.2.1 on Gentoo Linux, even with -Werror=array-bounds compiler option set.

[arximboldi]

You should be able to reproduce it using nix-shell --argstr compiler gcc like CI does.

[tusooa]

Yea, I can reproduce the error in nix but I have totally no idea why it fails.

[ 61%] Building CXX object test/CMakeFiles/test-transducer-read.dir/transducer/read.cpp.o
In file included from /home/user/Code/zug/zug/compose.hpp:11,
                 from /home/user/Code/zug/zug/transducer/map.hpp:11,
                 from /home/user/Code/zug/test/transducer/map.cpp:12:
In function 'decltype ((forward<Derived>)(zug::compat::detail::do_invoke::ref).*zug::compat::detail::do_invoke::pmf((forward<Args>)(zug::compat::detail::do_invoke::args)...)) zug::compat::detail::do_invoke(T Base::*, Derived&&, Args&& ...) [with Base = {anonymous}::Foo; T = const int&() const; Derived = {anonymous}::Foo&; Args = {}; <template-parameter-1-5> = void]',
    inlined from 'decltype (zug::compat::detail::do_invoke(forward<F>(f), (forward<ArgTypes>)(zug::compat::invoke::args)...)) zug::compat::invoke(F&&, ArgTypes&& ...) [with F = const int& ({anonymous}::Foo::*&)() const; ArgTypes = {{anonymous}::Foo&}]' at /home/user/Code/zug/zug/compat/invoke.hpp:54:29,
    inlined from 'zug::map_t<const int& ({anonymous}::Foo::*)() const>::operator()<const zug::output_t&>(const zug::output_t&) const::<lambda(auto:1&&, auto:2&& ...)> mutable [with auto:1 = std::back_insert_iterator<std::vector<int> >; auto:2 = {{anonymous}::Foo&}]' at /home/user/Code/zug/zug/transducer/map.hpp:23:24,
    inlined from 'std::decay_t<decltype (step(initial, (* std::begin(range))))> zug::detail::reduce_nested_non_empty_non_variadic(ReducingFnT&&, StateT&&, InputRangeT&&) [with ReducingFnT = zug::map_t<const int& ({anonymous}::Foo::*)() const>::operator()<const zug::output_t&>(const zug::output_t&) const::<lambda(auto:1&&, auto:2&& ...)>; StateT = std::back_insert_iterator<std::vector<int> >; InputRangeT = std::vector<{anonymous}::Foo>&]' at /home/user/Code/zug/zug/detail/reduce_nested_non_empty_non_variadic.hpp:33:13,
    inlined from 'decltype(auto) zug::detail::reduce_nested_non_empty(ReducingFnT&&, StateT&&, InputRangeT&&) [with ReducingFnT = zug::map_t<const int& ({anonymous}::Foo::*)() const>::operator()<const zug::output_t&>(const zug::output_t&) const::<lambda(auto:1&&, auto:2&& ...)>; StateT = std::back_insert_iterator<std::vector<int> >; InputRangeT = std::vector<{anonymous}::Foo>&]' at /home/user/Code/zug/zug/detail/reduce_nested_non_empty.hpp:51:57,
    inlined from 'auto zug::reduce(ReducingFnT&&, StateT&&, InputRangeTs&& ...) [with ReducingFnT = map_t<const int& ({anonymous}::Foo::*)() const>::operator()<const zug::output_t&>(const zug::output_t&) const::<lambda(auto:1&&, auto:2&& ...)>; StateT = std::back_insert_iterator<std::vector<int> >; InputRangeTs = {std::vector<{anonymous}::Foo, std::allocator<{anonymous}::Foo> >&}]' at /home/user/Code/zug/zug/reduce.hpp:72:64,
    inlined from 'std::decay_t<StateT> zug::transduce(XformT&&, ReducingFnT&&, StateT&&, InputRangeTs&& ...) [with XformT = composed<map_t<const int& ({anonymous}::Foo::*)() const> >; ReducingFnT = const output_t&; StateT = std::back_insert_iterator<std::vector<int> >; InputRangeTs = {std::vector<{anonymous}::Foo, std::allocator<{anonymous}::Foo> >&}]' at /home/user/Code/zug/zug/transduce.hpp:31:18,
    inlined from 'CollectionT&& zug::into(CollectionT&&, XformT&&, InputRangeTs&& ...) [with CollectionT = std::vector<int>; XformT = composed<map_t<const int& ({anonymous}::Foo::*)() const> >; InputRangeTs = {std::vector<{anonymous}::Foo, std::allocator<{anonymous}::Foo> >&}]' at /home/user/Code/zug/zug/into.hpp:34:14,
    inlined from 'std::vector<typename zug::result_of<XformT, typename std::decay<InputRangeTs>::type::value_type ...>::type> zug::into_vector(XformT&&, InputRangeTs&& ...) [with XformT = composed<map_t<const int& ({anonymous}::Foo::*)() const> >; InputRangeTs = {std::vector<{anonymous}::Foo, std::allocator<{anonymous}::Foo> >&}]' at /home/user/Code/zug/zug/into_vector.hpp:35:54,
    inlined from 'void C_A_T_C_H_T_E_S_T_6()' at /home/user/Code/zug/test/transducer/map.cpp:55:44:
/home/user/Code/zug/zug/compat/invoke.hpp:37:40: error: array subscript 'int (**)(...)[0]' is partly outside array bounds of 'unsigned char [4]' [-Werror=array-bounds]
   37 |                                    pmf)(std::forward<Args>(args)...))
      |                                        ^
/home/user/Code/zug/zug/compat/invoke.hpp:20:35: note: in definition of macro 'ZUG_DETAIL_DECLTYPE_RETURN'
   20 |     decltype(body_expr) { return (body_expr); }
      |                                   ^~~~~~~~~
In file included from /nix/store/kf147vkmb7a7z17lkpgj2d6y7w75nf7v-gcc-12.2.0/include/c++/12.2.0/x86_64-unknown-linux-gnu/bits/c++allocator.h:33,
                 from /nix/store/kf147vkmb7a7z17lkpgj2d6y7w75nf7v-gcc-12.2.0/include/c++/12.2.0/bits/allocator.h:46,
                 from /nix/store/kf147vkmb7a7z17lkpgj2d6y7w75nf7v-gcc-12.2.0/include/c++/12.2.0/string:41,
                 from /nix/store/kf147vkmb7a7z17lkpgj2d6y7w75nf7v-gcc-12.2.0/include/c++/12.2.0/bits/locale_classes.h:40,
                 from /nix/store/kf147vkmb7a7z17lkpgj2d6y7w75nf7v-gcc-12.2.0/include/c++/12.2.0/bits/ios_base.h:41,
                 from /nix/store/kf147vkmb7a7z17lkpgj2d6y7w75nf7v-gcc-12.2.0/include/c++/12.2.0/streambuf:41,
                 from /nix/store/kf147vkmb7a7z17lkpgj2d6y7w75nf7v-gcc-12.2.0/include/c++/12.2.0/bits/streambuf_iterator.h:35,
                 from /nix/store/kf147vkmb7a7z17lkpgj2d6y7w75nf7v-gcc-12.2.0/include/c++/12.2.0/iterator:66,
                 from /home/user/Code/zug/zug/detail/is_non_empty.hpp:11,
                 from /home/user/Code/zug/zug/reduce.hpp:11,
                 from /home/user/Code/zug/zug/transduce.hpp:11,
                 from /home/user/Code/zug/zug/into.hpp:13,
                 from /home/user/Code/zug/test/transducer/map.cpp:9:
In member function '_Tp* std::__new_allocator<_Tp>::allocate(size_type, const void*) [with _Tp = {anonymous}::Foo]',
    inlined from 'static _Tp* std::allocator_traits<std::allocator<_CharT> >::allocate(allocator_type&, size_type) [with _Tp = {anonymous}::Foo]' at /nix/store/kf147vkmb7a7z17lkpgj2d6y7w75nf7v-gcc-12.2.0/include/c++/12.2.0/bits/alloc_traits.h:464:28,
    inlined from 'std::_Vector_base<_Tp, _Alloc>::pointer std::_Vector_base<_Tp, _Alloc>::_M_allocate(std::size_t) [with _Tp = {anonymous}::Foo; _Alloc = std::allocator<{anonymous}::Foo>]' at /nix/store/kf147vkmb7a7z17lkpgj2d6y7w75nf7v-gcc-12.2.0/include/c++/12.2.0/bits/stl_vector.h:378:33,
    inlined from 'void std::vector<_Tp, _Alloc>::_M_range_initialize(_ForwardIterator, _ForwardIterator, std::forward_iterator_tag) [with _ForwardIterator = const {anonymous}::Foo*; _Tp = {anonymous}::Foo; _Alloc = std::allocator<{anonymous}::Foo>]' at /nix/store/kf147vkmb7a7z17lkpgj2d6y7w75nf7v-gcc-12.2.0/include/c++/12.2.0/bits/stl_vector.h:1687:25,
    inlined from 'std::vector<_Tp, _Alloc>::vector(std::initializer_list<_Tp>, const allocator_type&) [with _Tp = {anonymous}::Foo; _Alloc = std::allocator<{anonymous}::Foo>]' at /nix/store/kf147vkmb7a7z17lkpgj2d6y7w75nf7v-gcc-12.2.0/include/c++/12.2.0/bits/stl_vector.h:677:21,
    inlined from 'void C_A_T_C_H_T_E_S_T_6()' at /home/user/Code/zug/test/transducer/map.cpp:54:34:
/nix/store/kf147vkmb7a7z17lkpgj2d6y7w75nf7v-gcc-12.2.0/include/c++/12.2.0/bits/new_allocator.h:137:55: note: object of size 4 allocated by 'operator new'
  137 |         return static_cast<_Tp*>(_GLIBCXX_OPERATOR_NEW(__n * sizeof(_Tp)));
      |                                                       ^
cc1plus: all warnings being treated as errors