view: prepare to pass the tombstone check flag to base classes and iterators

src/entt/entity/view.hpp

@@ -18,6 +18,9 @@ namespace entt {
 /*! @cond TURN_OFF_DOXYGEN */
 namespace internal {
 
+template<typename... Type>
+static constexpr bool tombstone_check_v = ((sizeof...(Type) == 1u) && ... && (Type::storage_policy == deletion_policy::in_place));
+
 template<typename Type>
 const Type *view_placeholder() {
     static_assert(std::is_same_v<std::remove_const_t<std::remove_reference_t<Type>>, Type>, "Unexpected type");
@@ -457,10 +460,8 @@ class basic_view<get_t<Get...>, exclude_t<Exclude...>, std::enable_if_t<(sizeof.
 
     template<std::size_t Curr, typename Func, std::size_t... Index>
     void each(Func &func, std::index_sequence<Index...>) const {
-        static constexpr bool tombstone_check_required = ((sizeof...(Get) == 1u) && ... && (Get::storage_policy == deletion_policy::in_place));
-
         for(const auto curr: storage<Curr>()->each()) {
-            if(const auto entt = std::get<0>(curr); (!tombstone_check_required || (entt != tombstone)) && ((Curr == Index || base_type::pool_at(Index)->contains(entt)) && ...) && base_type::none_of(entt)) {
+            if(const auto entt = std::get<0>(curr); (!internal::tombstone_check_v<Get...> || (entt != tombstone)) && ((Curr == Index || base_type::pool_at(Index)->contains(entt)) && ...) && base_type::none_of(entt)) {
                 if constexpr(is_applicable_v<Func, decltype(std::tuple_cat(std::tuple<entity_type>{}, std::declval<basic_view>().get({})))>) {
                     std::apply(func, std::tuple_cat(std::make_tuple(entt), dispatch_get<Curr, Index>(curr)...));
                 } else {