- typedef std::unordered_set<std::size_t> page_set_type;
- typedef std::unordered_map<hash_type, page_set_type> pages_map_type;
+ using page_set_type = std::unordered_set<std::size_t>;
+ using pages_map_type = std::unordered_map<hash_type, page_set_type>;