- Added overloading of compound assignment via new traits, empty struct brace syntax, and stabilized many library APIs (e.g., str::encode_utf16, Instant methods, BTree set covariance).
- Deprecated Unix-specific raw modules and introduced breaking changes such as widened integer returns in MetadataExt, stricter module placement rules, and stricter cfg identifier parsing.
- Enhanced Cargo (cargo init, config env overrides, target‑specific dependencies) and rustc (new Cargo‑based build, performance gains, disabled executable stacks, Windows lib naming changes) with security and usability improvements.