[Bug libstdc++/102825] std::move_only_function's implementation breaking existing code

[hewillk at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102825

--- Comment #1 from 康桓瑋 <hewillk at gmail dot com> ---
(In reply to 康桓瑋 from comment #0)
> mofunc_impl.h#L111:
> 
>   : _Mofunc_base(nullptr), _M_invoke(&_S_invoke<_Tp>)
> 
> _Mofunc_basede does not have a constructor which accepts a nullptr.
> 
> #include <functional>
> https://godbolt.org/z/59T4obz4j

gcc test:

#include <functional>

struct F { 
  F(std::initializer_list<int>);
  void operator()() const; 
};

int main() {
  std::move_only_function<void(void)> f(std::in_place_type<F>, {0});
}

https://godbolt.org/z/8qsEqbh9s