{
"id": "rust-chars-nth-in-loop",
"language": "rust",
"group": "performance",
"listingTitle": "Avoid repeatedly indexing Rust strings by character",
"title": "Avoid repeatedly indexing Rust strings by character",
"mvvm": false,
"defaultSeverity": "warn",
"legacyGroup": "performance",
"why": "chars().nth(index) starts decoding UTF-8 from the beginning, so index-driven use inside a loop can become quadratic.",
"suggestion": "Iterate with chars or char_indices once, or materialize an index only when repeated random character access is required.",
"version": 1,
"semanticMaturity": "token",
"securityKind": "none",
"taxonomy": ["performance"],
"requirements": ["sourceText"],
"packs": ["rust", "cargo"],
"implementation": "src/languages/rust/rules.rs",
"languages": ["rust"],
"frameworks": [],
"languageVersions": [],
"limitations": [
"Only identifier receivers followed by chars().nth(identifier) inside recognized braced loops are reported.",
"Receiver types, iterator reuse, loop bounds, aliases, and whether indexing is material on the current path are not inferred."
]
}