Rest parameters in a snippet should be a compile error

[Rich-Harris]

Describe the bug

We error on this...

{#snippet a(b)}
  {b}
{/snippet}

{@render a(...[1])}

...but not this:

{#snippet a(...b)}
  {b[0]}
{/snippet}

{@render a(1)}

Instead, it fails cryptically at runtime.

Reproduction

see above

Logs

No response

System Info

next

Severity

annoyance

[FoHoOV]

Can't svelte allow snippets to fully support rest params?

[Conduitry]

Perhaps at some point. There's an issue for it post-5.0 - #11178