Compiler crashes with orphaned :global in CSS

[dimfeld]

Describe the bug

CSS like this causes the Svelte compiler to crash:

<style>
  .codemirror-container.flex :global {padding:0}
</style>

To Reproduce
https://svelte.dev/repl/c0b2792175ab48c0afb84b01b9bfa247?version=3.23.0

Expected behavior
Throw an error instead of crashing.

Severity

Very minor since it's invalid syntax and nobody would intentionally write this. This happened because I had purgecss in my postcss preprocessor config and I needed to whitelist some classes.

[Conduitry]

This now throws a more helpful error in 3.23.1 - https://svelte.dev/repl/c0b2792175ab48c0afb84b01b9bfa247?version=3.23.1