81 class function_ref;  variable
84 class function_ref<Ret(Args...)> final {
86   constexpr function_ref() noexcept = delete;
87   constexpr function_ref(const function_ref& other) noexcept = default;
88   constexpr function_ref& operator=(const function_ref&) noexcept = default;
92   function_ref(RawFunc* funcptr) noexcept { *this = funcptr; }  in function_ref()  function
96                                 !std::is_same_v<function_ref, std::remove_reference_t<Callable>>>>
97   function_ref(Callable&& c) noexcept {  in function_ref()  function
101   function_ref& operator=(RawFunc* funcptr) noexcept {
111                                 !std::is_same_v<function_ref, std::remove_reference_t<Callable>>>>
112   function_ref& operator=(Callable&& c) noexcept {