[Bug c++/107955] New: ICE: trying to capture ‘ARGS#0’ in instantiation of generic lambda

["onebit74 at gmail dot com" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107955

            Bug ID: 107955
           Summary: ICE: trying to capture ‘ARGS#0’ in instantiation of
                    generic  lambda
           Product: gcc
           Version: 12.2.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: onebit74 at gmail dot com
  Target Milestone: ---

The code is valid
If you comment out the if, it compiles.
If you comment out the branches in the if, it compiles as well.

But somehow putting them together gives ICE.


#include <functional>

template<typename F>
struct agg_p {
        F f;


        void _parse(auto...ARGS){
                [&](auto...P_ARGS){
                        using result =
std::invoke_result_t<F,decltype(ARGS)...,decltype(P_ARGS)...>;
                        if constexpr(!std::same_as<result, void>){
                                f(ARGS...,P_ARGS...);
                        }else{
                                f(ARGS...,P_ARGS...);
                        }
                }(1);
        }

};

int main(){
        auto add = [](auto a, auto b){return a+b;};
        auto agg = agg_p(add);
        int i;
        agg._parse(i);
}