destructuring {#each} with fallback has type inference error

[cloudymeatball]

Describe the bug

From svelte@5.13.0, destructuring {#each} with default fallbacks leads to Cannot find name 'variableName'.

Reproduction

In svelte@5.12.0, we could do something like this

<script lang=ts>
  let arr = [['123'], ['456', '789']]
</script>
{#each arr as [key, value = 'default']}
  <div>{key}: {value}</div>
{/each}

But in 5.13.0 the same code has typescript errors
Cannot find name 'key', Cannot find name 'value', ',' expected.

Logs

No response

System Info

svelte@^5.13.0, typescript@^5 with either vite5 or vite6, with or without the corresponding @sveltejs/vite-plugin-svelte.

Severity

blocking an upgrade

[Ocean-OS]

From the code you provided, there doesn't seem to be any issues, could you provide a REPL link that reproduces the issue?

[cloudymeatball]

It was not reproducible with playground. With VS Code svelte language server running (restart if necessary), I see the errors when copy pasting into a svelte component file.

https://github.com/cloudymeatball/svelte-each

[paoloricciuti]

Ok i dug this a bit...it should be a bug with the loose parser...will explore a bit more