legacy-conventions

name	legacy-conventions
description	MUST consult before writing any code related to Svelte 4 legacy features. Contains mandatory naming conventions, doc-comment format, and isolation rules for legacy code. Use this skill whenever touching on:directive, bind:this legacy syntax, Svelte 4 deprecated features, code marked LEGACY(svelte4), or when porting/implementing any feature that has both a Svelte 5 and a Svelte 4 variant. Failure to follow these conventions creates tech debt that blocks future cleanup.
paths	["**/*.rs"]

Legacy Feature Conventions (Svelte 4)

Legacy Svelte 4 syntax (deprecated in Svelte 5, scheduled for removal in Svelte 6) is ported with isolation in mind so it can be cleanly deleted later.

Conventions

1. Legacy suffix in all type/function names: OnDirectiveLegacy, gen_on_directive_legacy, build_legacy_event_handler.
2. LEGACY(svelte4): doc-comment on every struct, enum variant, and top-level function:

   /// LEGACY(svelte4): on:directive syntax. Deprecated in Svelte 5, remove in Svelte 6.
   pub struct OnDirectiveLegacy { ... }
   

   Short inline comments use the same tag: // LEGACY(svelte4): on:directive handled separately.
3. Easy removal — keep legacy code in self-contained blocks/functions. Avoid mixing legacy logic into non-legacy code paths. Ideal: grep LEGACY(svelte4) -> delete all hits -> compile -> done.