Rust Clippy and Linter (cargo clippy)

Executes Rust's static analyzer cargo clippy and formatter rustfmt. Resolves borrow-checker conflicts, unnecessary allocations, and clippy lints without #![allow(...)].

1. Purpose

Eliminate performance antipatterns and borrow-checker hazards in Rust.

2. When to Use

Use this skill when:

• Checking Rust code before committing.
• Resolving cargo clippy -- -D warnings errors.
• Resolving borrow checker errors (E0382: borrow of moved value, E0502: cannot borrow as mutable).

3. When Not to Use

• Do not use for running tests; use rust-testing.

4. Required Inputs

• crate_path: Path to Cargo crate (default: .).

5. Missing-Input Behavior

1. If not specified: default to current directory.
2. Strict Ban: Never add #![allow(clippy::...)] without explicit user permission.

6. Procedure

Follow these numbered actions:

1. Action 1: Run Cargo Check
   • Execute: cargo check
2. Action 2: Run Cargo Clippy
   • Execute: cargo clippy --all-targets -- -D warnings
3. Action 3: Resolve Borrow Checker & Allocation Lints
   • Use references (&T) instead of cloning (.clone()) where possible.
   • Replace manual loops with iterator combinators where recommended.
4. Action 4: Format Code
   • Execute: cargo fmt
5. Action 5: Re-verify
   • Confirm exit code 0 on cargo clippy.

7. Decision Rules

• If clippy recommends .into_iter() vs .iter(): follow borrow vs move semantics.

8. Output Format

Emit the report using this template:

### Rust Clippy Report: [Crate]

- **Clippy Command**: `cargo clippy -- -D warnings` -> PASS
- **Format Command**: `cargo fmt -- --check` -> PASS
- **Lints Resolved**: [Count]

#### Resolved Lints
- `[file:line]`: [Clippy lint name and fix description]

9. Verification Checklist

• cargo clippy exits with code 0.
• No #![allow(...)] overrides added.
• Code formatted with cargo fmt.

10. Common Failures and Recovery

11. Stop or Escalation Conditions

Stop and ask the user when:

• Resolving borrow requires redesigning core data structures (e.g. using Arc<Mutex<T>>).

12. Examples

Example 1: Successful Execution

Input:

Crate: .
Error: clippy::needless_borrow on &String

Output:

### Rust Clippy Report: .

- **Clippy Command**: `cargo clippy -- -D warnings` -> PASS
- **Format Command**: `cargo fmt -- --check` -> PASS
- **Lints Resolved**: 1

#### Resolved Lints
- `src/main.rs:18`: Removed redundant borrow `&s` where `&str` was already expected.

Example 2: Ambiguous or Missing Input

Input:

Clippy check.

Output:

### Rust Clippy Report: .

- **Clippy Command**: `cargo clippy -- -D warnings` -> PASS
- **Lints Resolved**: 0

Example 3: Expected Final Output

Output:

### Rust Clippy Report: parser-crate

- **Clippy Command**: `cargo clippy -- -D warnings` -> PASS
- **Lints Resolved**: 3