Реализация Swift словаря

Как обычно, обо всех неточностях, ошибках и просто казусах перевода прошу сообщать в ЛС. Спасибо.

Тогда уж и коммент из источника возьмем

It seems you're using first-come-first-serve linear probing. Why not robinhood (with backshifting)? As far as I know, this significantly improves average search times, even when increasing the load factor. This is the current strategy that Rust's HashMap takes (load factor 0.91).

Instead of a bitset, we also store the hashes themselves to facilitate the robinhood checking (we set the most-significant bit of hashes so 0 doesn't occur naturally). This also provides a fastpath for equality checking. Even under a collision, the full (63-bit) hash is unlikely to be equal, so you only only ever incur the cost of looking at the keys when you hit an exact hash-match, which is almost guaranteed to be an exact key match. You don't expect to ever look at the keys if the key isn't present.