Use only for reviewing completed Biome PRs, branches, commit ranges, diffs, or working trees against business logic and requirements. Excludes broad code-quality and process audits, triage, reproduction, and implementation.
Apply production totality, including caller guarantees. No concrete failing input is required; test-only code is exempt.
Construct
Review rule
Panic macros and assert!
Establish that the panic path is unreachable or the assertion always holds
unwrap, expect, index, slice
Establish success, presence, or valid bounds through guards, types, or caller contracts
Partial collection/string methods
Identify the receiver and establish that every index and UTF-8 boundary is valid
Integer division/remainder
Establish a nonzero divisor and absence of arithmetic overflow
Comments, debug assertions, and passing tests are supporting evidence, not release-mode guards. Consolidate shared missing guarantees or failures; exclude unrelated legacy code.
Suggest establishing the invariant or using a total operation while preserving error/recovery behavior, not blanket fallible-API conversions.
Syntax Text and Ranges
Load syntax-text-handling for implementation contracts.
SyntaxNode::text_trimmed() retains trivia between child tokens. Do not compare a multi-token node's text to a semantic literal.
Token comparisons and hashes use trimmed token accessors so attached trivia cannot change behavior.
Check language-specific quote semantics and string boundaries when slicing; helper choice alone is not a finding.
A token-relative range used as a diagnostic must be translated to the file range exactly once, including any quote offset.
Treat trivia and range mistakes as correctness issues, not merely performance issues.
Allocation and Analyzer Phases
Cite the affected path and violated requirement or avoidable cost. A possible borrowed representation alone does not justify a rewrite.
run() decides whether to signal; action() constructs a fix. Data used only by the action should not be built in run().
Prefer borrows or Cow when the source buffer remains available.
Report an owning field type once at its definition rather than every allocation it forces.
Avoid caches, memoization, and hand-rolled fast paths without benchmark evidence and a correct invalidation strategy.
API Shape
For affected APIs, distinguish contracts from heuristics. Report violations or concrete impact, not preferred signatures or abstractions; keep remediation local.
Language-specific behavior belongs in its language crate.
Generic CST questions belong in syntax extension traits; consumer-specific policy belongs in the analyzer or formatter using it.
Functions inspecting CST should accept typed nodes or a declared node union rather than raw syntax nodes.
A helper should isolate a domain operation or invariant, not merely rename an expression.
Repeated parameters across a cluster of free functions often indicate state that belongs in a struct.
Derive only traits used by the implementation or callers.
Put generic bounds on implementations unless a field or language rule requires them on the type.
Prefer Option<&T> to &Option<T>. A function that immediately applies ? to an optional parameter probably should require T instead.
Recursion and Worklists
Check affected user-controlled traversals for reachable overflow or cycles; recursion alone is not a finding.
For a hand-written worklist, verify:
frame processing follows the required traversal order;
every early exit restores externally owned state;
LIFO reversal preserves intended source or declaration order.
Error Handling
Do not discard errors needed by the reporting boundary with .ok(), let _ =, or an unrelated default.
Check required reporting through changed wrappers and fallbacks; abstraction preference alone is not a finding.
