uses a HAMT for the hash map in its persistent collections package. The im and im-rc crates, which provide persistent collection types for the Rust programming language, use a HAMT for their persistent hash tables and hash sets. The concurrent lock-free version of the hash trie called Ctrie is a mutable thread-safe implementation which ensures progress. The data-structure has been proven to be correct - Ctrie operations have been shown to have the atomicity, linearizability and lock-freedom properties. See also Judy array Radix tree References Associative arrays Hashing