| name | rust-no-magic-values |
| description | Applies common production Rust practices to remove magic literals: named consts, enums, newtypes, and centralized schema strings. Use when writing or reviewing Rust, when the user mentions magic strings/numbers, duplicated literals, or when designing core versus adapter layers. |
Rust — no magic literals
What serious codebases typically do
- Compiler and Clippy: favor
const and rich types; teams often enable lints that reduce fragile unwrap patterns.
const / static: protocol values and defaults live in dedicated modules so the meaning of each number has one home.- Enums: closed sets with exhaustive
match; prevent typos and drift across call sites.
- Newtypes:
struct X(u32) or typed arrays (Eui64) to avoid mixing units or semantics.
- Adapter layer: table/column names and SQL fragments as
const or a schema module, not copy-paste.
- Configuration: operational policy belongs in config structs or named presets (e.g. install profile), not ad hoc literals inside logic.
Checklist when changing code
Anti-pattern
A helper that takes &str for “event kind” used from many places without an enum: every call site is a future bug.
