storage: try to address wrong code coverage results by lcov2

src/entt/entity/storage.hpp

@@ -309,19 +309,20 @@ class basic_storage: public basic_sparse_set<Entity, typename std::allocator_tra
         ENTT_ASSERT((from + 1u) && !is_pinned_type, "Pinned type");
 
         if constexpr(!is_pinned_type) {
+            using std::swap;
             auto &elem = element_at(from);
 
             if constexpr(traits_type::in_place_delete) {
-                if(base_type::operator[](to) == tombstone) {
+                const auto entt = base_type::operator[](to);
+
+                if(entt == tombstone) {
                     allocator_type allocator{get_allocator()};
                     entt::uninitialized_construct_using_allocator(to_address(assure_at_least(to)), allocator, std::move(elem));
                     alloc_traits::destroy(allocator, std::addressof(elem));
                 } else {
-                    using std::swap;
                     swap(elem, element_at(to));
                 }
             } else {
-                using std::swap;
                 swap(elem, element_at(to));
             }
         }