# Rust Dev > Read, write, and fix Rust code. Use for analyzing Rust errors, generating idiomatic Rust with ownership/borrowing/async patterns, fixing compilation errors, refactoring for performance and safety, and running cargo check/clippy/test. Use when this capability is needed. - Skill: `tomevault-io/rust-dev-2` (Agent Skill, multi-file: 2 files) - Install (CLI): `npx skillmds@latest add tomevault-io/rust-dev-2` - Raw SKILL.md: https://api.skillmd.com/api/skills/tomevault-io/rust-dev-2/raw - Safety review: pending (external: skill-scanner PASS, skillspector CAUTION) - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: Coding & Dev Tools - Author: tomevault-io (https://skillmd.com/u/tomevault-io) - Updated: 2026-09-17 - Page: https://skillmd.com/skills/tomevault-io/rust-dev-2 --- # Rust Developer Analyze, write, and fix Rust code iteratively until it compiles and passes tests. ## When to Use - Fix or diagnose Rust compilation errors - Write new Rust functions, structs, traits, or modules - Refactor Rust code for performance, safety, or idiomatic style - Add or fix async/await code, ownership patterns, or lifetime annotations - Lint and clean up Rust code with Clippy ## Procedure ### 1. Understand the Task - If the task lacks a specific file, error message, or function, ask one clarifying question before proceeding. - Read the relevant source files before making changes - Identify the exact error, goal, or refactor target - Note ownership, lifetime, and async constraints in context - Handle errors gracefully: if the task is too vague (e.g., 'fix my Rust code' with no file or error specified), ask for clarification. ### 2. Implement Changes - Prefer idiomatic Rust: use `?` for error propagation, `impl Trait` for flexibility, iterators over manual loops - Follow ownership rules: minimize clones, prefer borrows, use `Arc`/`Mutex` only when shared mutability is necessary - Do not add new crate dependencies without asking. Prefer solutions using the standard library and existing dependencies. - For async code: use `.await` correctly, avoid blocking in async contexts, prefer `tokio` patterns already in the codebase - Match the existing code style and module conventions ### 3. Verify with `cargo check` Run `cargo check` to catch compile errors quickly: ``` cargo check ``` - If Cargo commands cannot be executed in the environment, perform manual static analysis based on the code and clearly state that automated verification was not possible. - If errors remain, read the compiler output carefully — Rust errors are precise - Fix each error and re-run until clean - For workspace crates, use `cargo check -p ` to target a specific crate ### 4. Lint with `cargo clippy` ``` cargo clippy ``` - Address `warning` and `error` level lints - Use `#[allow(...)]` sparingly and only with justification - Clippy suggestions are usually idiomatic improvements — apply them ### 5. Validate with `cargo test` ``` cargo test ``` - Run the full test suite; for a single crate: `cargo test -p ` - If tests fail, diagnose whether the fix broke existing behavior or the test expectations need updating - Do not delete or skip tests to make them pass ### 6. Iterate Until Green Repeat steps 3–5 until: - `cargo check` exits with no errors - `cargo clippy` shows no warnings or errors in the targeted crate(s) or touched files - `cargo test` passes all relevant tests ### 7. Explain Changes After completing the fix, briefly summarize: - What was wrong or missing - What pattern or Rust feature was applied - Any trade-offs made (e.g., cloning vs. restructuring lifetimes) ## Idiomatic Rust Patterns | Goal | Preferred Pattern | |------|------------------| | Error handling | `Result` + `?` operator | | Optional values | `Option` + `map`/`and_then` | | Shared ownership | `Arc` (thread-safe), `Rc` (single-thread) | | Interior mutability | `Mutex`, `RwLock`, `Cell`, `RefCell` | | Async runtime | `tokio::spawn`, `.await`, `async fn` | | Collections | Iterators + `collect()` over manual loops | | Newtype pattern | Wrap primitives for type safety | | Builder pattern | For structs with many optional fields | ## Common Compiler Error Fixes - **E0382 use of moved value**: borrow instead of move, or clone if ownership must be transferred - **E0502 conflicting borrows**: restructure to avoid overlapping mutable/immutable borrows - **E0277 trait not implemented**: add a `where` bound or implement the trait - **E0106 missing lifetime specifier**: introduce lifetime annotations or use owned types - **E0716 temporary dropped while borrowed**: extend the lifetime of the temporary with a `let` binding ## Quality Checklist - [ ] `cargo check` passes with no errors - [ ] `cargo clippy` introduces no new warnings - [ ] `cargo test` passes all tests - [ ] No unnecessary `clone()`, `unwrap()`, or `expect()` in production paths - [ ] Async code does not block the executor - [ ] Public APIs have doc comments if the codebase uses them --- > Source: [kowito/chopin](https://github.com/kowito/chopin) — distributed by [TomeVault](https://tomevault.io).