# Anti Patterns

> Identify and refactor Rust anti-patterns and clippy anti-idioms. Use when reviewing Rust code for smells, hunting anti-patterns to fix or remove, or refactoring code that clones to satisfy the borrow checker, takes &String/&Vec parameters, unwraps on fallible paths, or returns sentinel values instead of Option/Result.

- Skill: `vinnie357/anti-patterns` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds add vinnie357/anti-patterns`
- Raw SKILL.md: https://api.skillmd.com/api/skills/vinnie357/anti-patterns/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- License: MIT
- Author: vinnie357 (https://skillmd.com/u/vinnie357)
- Updated: 2026-09-10
- Page: https://skillmd.com/skills/vinnie357/anti-patterns

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# Rust Anti-Patterns

Catalog of Rust anti-patterns and clippy anti-idioms for reviewers and implementers actively hunting code to fix or remove. Complements `/rust:troubleshooting` (which teaches the idiomatic GOOD patterns) by naming the BAD patterns explicitly, with detection hints.

## Sources

Rust Design Patterns book ([anti-patterns](https://rust-unofficial.github.io/patterns/anti_patterns/), [idioms](https://rust-unofficial.github.io/patterns/idioms/)) and the [Clippy lint index](https://rust-lang.github.io/rust-clippy/master/index.html) — full attribution per entry in `references/anti-patterns.md`, dated URLs in `sources.md`.

## Example

```rust
// BAD: clippy::ptr_arg — forces callers to hold an owned Vec
fn process(data: &Vec<i32>) { /* ... */ }

// GOOD: accepts a Vec, an array, or a slice via deref coercion
fn process(data: &[i32]) { /* ... */ }
```

The full catalog (9 entries) is in `references/anti-patterns.md`.

## Usage Guidelines

1. **Scan for the pattern** — check the diff or module against `references/anti-patterns.md`
2. **Confirm it's not deliberate** — a `restraint:` comment or documented tradeoff can justify what looks like an anti-pattern; anti-patterns are defaults to avoid, not absolute bans
3. **Fix at the root** — apply the GOOD replacement, don't just silence the lint
4. **Cite the source** — when flagging in review, reference the anti-pattern name so the author can look it up

## Anti-Fabrication

Every entry in `references/anti-patterns.md` cites its source URL. Do not assert a clippy lint name, its default-enabled status, or a "this catches N% of cases" claim without verifying against the linked clippy documentation — see `/core:anti-fabrication`.