Upgrades to the latest version of Acorn, and replacesecmaVersion: 16 with'latest' which allows Svelte code to use theusing keyword (which is now stage 4, i.e. part of the language).

I didn't think it worthwhile to add a test (would be like having a test forvar declarations or whatever) but you can easily see itworking in the playground once it deploys.

One thing wecould conceivably do is transform components with top-levelusing such that disposals don't occur until the component is removed. This would mean wrapping everything in an async function that ends with something like this:

returnnewPromise((fulfil)=>{$effect(()=>fulfil);});

Personally I'm not sold on the idea — it's a little magical, and would prevent the component from exporting values — but I raise it as a possibility for discussion. If we thought wemight want to add that capability in future we could always prevent the usage of top-levelusing, though that itself might be annoying.

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• It's really useful if your PR references an issue where it is discussed ahead of time. In many cases, features are absent for a reason. For large changes, please create an RFC:https://github.com/sveltejs/rfcs
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Tests and linting

• Run the tests withpnpm test and lint the project withpnpm lint