On 64-bit little-endian targets ScrStr's capacity word is split into a
32-bit cap and a 32-bit cached Map key hash (header stays 24 bytes).
Heap strings fill the hash on first lookup; every in-place mutation path
(unique concat, split scratch reuse, regrow, spare reuse) clears it.
Immortal strings are never written: compiler literals and the runtime's
one-character/empty statics carry the hash precomputed (string-key-hash.ts
mirrors scr_key_hash; both sides pin the same vectors).
scr_key_hash seeds by length multiplicatively: XORing the length into the
low bits cancelled against the last byte ("ab" and "abc" collided).
Map string lookups inline the probe into each getter and reject linear
entries by hash; set specializes its probe/overwrite by lookup kind with a
shared append path.
Tests: runtime map.test.ts (pinned vectors, statics, in-place append
invalidation), string-key-hash.test.ts, corpus 3141-map-string-key-hash
(plain + sanitized; mutation-checked against both invalidation paths).
- Borrow rooted collection receivers across safe helpers and typed updates.
- Keep small Maps and Sets compact through cloning, growth, and live iteration.
- Preserve ownership at reassignment, exception, and capture boundaries.
- Support boolean, bigint, and mixed value keys in native Maps and Sets.
- Reuse key hashes and copy collections directly into compact storage.
- Preserve collection identity, ordering, iteration, and ownership behavior.
* feat(compiler): advance self-hosting with identity collections
- Support reference identity in Maps and Sets, including unions and cycle cleanup.
- Run production integer-range analysis natively with typed IR traversal.
- Add differential coverage for native analyses and collection behavior.
* chore: ignore generated output directories
- Exclude generated output directories from version control.
Malte Ubl