Thalarch Rust

Use the repository's toolchain/MSRV, Cargo features, async runtime, lint policy, and architecture. Do not require the newest edition or rewrite working code merely to use newer syntax.

Preflight

Inspect:

• Cargo.toml workspace/package structure;
• rust-toolchain* and MSRV policy;
• feature flags/default features;
• async runtime and ecosystem dependencies;
• clippy/format/test/CI configuration;
• generated/FFI/unsafe boundaries.

Ownership and API design

Prefer ownership/borrowing that makes lifetime and mutation intent obvious.

• Avoid cloning solely to appease the borrow checker without understanding ownership.
• Avoid complex lifetime machinery when a simpler owned boundary is clearer and acceptable.
• Preserve public error and feature contracts.
• Use enums/newtypes where they eliminate invalid states or ambiguous primitives.
• Keep trait abstractions tied to real polymorphism/generic requirements rather than speculative flexibility.

Errors

• Use Result/? for recoverable failure propagation.
• Add context at boundaries where it helps operators/callers.
• Do not unwrap/expect on production paths unless the invariant is truly impossible to violate and the reason is evident.
• Preserve error source chains where the project ecosystem supports them.

Unsafe and FFI

Treat unsafe as a separate proof obligation.

For every new/changed unsafe block:

• state the invariant that makes it sound;
• identify pointer/aliasing/lifetime/thread-safety assumptions;
• keep the unsafe surface minimal;
• prefer a small safe wrapper around it;
• run targeted tests/sanitizer/Miri-style tools if the repository already supports them or the risk warrants setup.

Do not expand unsafe code as a performance guess.

Async/concurrency

Preserve the existing runtime (Tokio/async-std/smol/etc.) unless the task explicitly changes it. Review task ownership, cancellation, blocking calls on async executors, channel backpressure, shared-state locking, Send/Sync assumptions, and task leaks.

Testing

Use unit/integration/doc tests according to the contract. Add property/fuzz tests for parsers, protocols, codecs, state machines, or invariant-heavy code when tooling is available/justified.

Run repository-native cargo test; use cargo fmt --check, cargo clippy, feature-matrix tests, or target checks when configured and relevant.

Performance

Profile/benchmark before optimizing. Examine allocations/copies, algorithmic complexity, lock contention, async scheduling, I/O, serialization, and cache behavior. Use the project's benchmark stack when present.

Verification

Report the toolchain/feature/target combination actually tested. A default-feature host build does not prove optional features or cross-target behavior.