dart3-idioms-and-coding-standardslisted

Enforces which Dart 3 construct each declaration earns — sealed class + exhaustive switch with no `default:`/`case _:`, the three class modifiers (`sealed`/`final`/`abstract interface class`) and skip the rest, records as intra-layer tuples only, immutable value types (`final` fields, `const` ctor, value equality) hand-rolled when trivial and `freezed` when boilerplate dominates, explicit stable identity, total non-throwing domain functions, make-illegal-states-unrepresentable, and firm method/build/file/nesting complexity limits (the single-source-of-truth table other skills cite) — while banning `late`/`!`/`dynamic` honesty dodges. Use when authoring or reviewing any Dart type or declaration: class vs enum vs record vs typedef, hand-rolled vs `freezed`, adding a `switch`/`if-case`, writing `copyWith` or `==`/`hashCode`, deciding identity, keeping a domain function total, or hitting a length/nesting limit.
zakariaf/CatchLaw · ★ 0 · Code & Development · score 58

Install: claude install-skill zakariaf/CatchLaw

# Dart 3 idioms and coding standards Modern Dart 3.x, value-type-first, total functions for domain logic. A language feature earns its place when it converts a runtime silence into a **compile error**; everything else is decoration. This skill governs how each declaration is *typed, named, kept immutable, and kept total* — the error-handling architecture that rides on top of these mechanics lives in `error-handling-typed-results`. Read the reference for the task at hand: - `references/construct-verdict-table.md` — the feature-by-feature verdict table (sealed / enum / record / class modifiers / `extension type` / codegen packages), with the rationale for each Use / Skip. - `references/immutability-and-equality.md` — immutable value types, `copyWith`, when to hand-write `==`/`hashCode`, and stable-identity vs value-equality. - `references/complexity-and-honesty.md` — the length/nesting limits with their evidence, and the `late`/`!`/`dynamic` honesty-dodge bans in full. Run `scripts/check-dart3-idioms.sh` before a PR. ## Non-negotiable rules 1. **A `switch` on a sealed type or enum carries no `default:` and no `case _:`.** A wildcard makes the switch compile forever, discarding the one compile-time guarantee the type exists for — adding a variant then falls through silently at runtime. Exhaustiveness is the whole product. 2. **Reach for exactly three class modifiers; ignore the rest.** `sealed class` for a closed variant set the compiler must exhaust; `final class` for eve