delegate: use type_list rather than tuple internally

src/entt/signal/delegate.hpp

@@ -100,7 +100,7 @@ class delegate<Ret(Args...)> {
     [[nodiscard]] auto wrap(std::index_sequence<Index...>) ENTT_NOEXCEPT {
         return [](const void *, Args... args) -> Ret {
             [[maybe_unused]] const auto arguments = std::forward_as_tuple(std::forward<Args>(args)...);
-            return Ret(std::invoke(Candidate, std::forward<std::tuple_element_t<Index, std::tuple<Args...>>>(std::get<Index>(arguments))...));
+            return Ret(std::invoke(Candidate, std::forward<type_list_element_t<Index, type_list<Args...>>>(std::get<Index>(arguments))...));
         };
     }
 
@@ -109,7 +109,7 @@ class delegate<Ret(Args...)> {
         return [](const void *payload, Args... args) -> Ret {
             [[maybe_unused]] const auto arguments = std::forward_as_tuple(std::forward<Args>(args)...);
             Type *curr = static_cast<Type *>(const_cast<constness_as_t<void, Type> *>(payload));
-            return Ret(std::invoke(Candidate, *curr, std::forward<std::tuple_element_t<Index, std::tuple<Args...>>>(std::get<Index>(arguments))...));
+            return Ret(std::invoke(Candidate, *curr, std::forward<type_list_element_t<Index, type_list<Args...>>>(std::get<Index>(arguments))...));
         };
     }
 
@@ -118,7 +118,7 @@ class delegate<Ret(Args...)> {
         return [](const void *payload, Args... args) -> Ret {
             [[maybe_unused]] const auto arguments = std::forward_as_tuple(std::forward<Args>(args)...);
             Type *curr = static_cast<Type *>(const_cast<constness_as_t<void, Type> *>(payload));
-            return Ret(std::invoke(Candidate, curr, std::forward<std::tuple_element_t<Index, std::tuple<Args...>>>(std::get<Index>(arguments))...));
+            return Ret(std::invoke(Candidate, curr, std::forward<type_list_element_t<Index, type_list<Args...>>>(std::get<Index>(arguments))...));
         };
     }
 
@@ -180,7 +180,7 @@ public:
                 return Ret(std::invoke(Candidate, std::forward<Args>(args)...));
             };
         } else if constexpr(std::is_member_pointer_v<decltype(Candidate)>) {
-            fn = wrap<Candidate>(internal::index_sequence_for<std::tuple_element_t<0, std::tuple<Args...>>>(internal::function_pointer_t<decltype(Candidate)>{}));
+            fn = wrap<Candidate>(internal::index_sequence_for<type_list_element_t<0, type_list<Args...>>>(internal::function_pointer_t<decltype(Candidate)>{}));
         } else {
             fn = wrap<Candidate>(internal::index_sequence_for(internal::function_pointer_t<decltype(Candidate)>{}));
         }