Unicode alphanumeric characters

[Florian-Mt]

Describe the bug

As of Svelte 5 RC releases, it is impossible to use Unicode alphanumeric characters to name a component.

For example, mixing different writing systems, having a file Cæжαकン中.svelte and trying to do import Cæжαकン中 from "./Cæжαकン中.svelte"; and <Cæжαकン中 /> now throws the error: Expected a valid element or component name. Components must have a valid variable name or dot notation expression.

It used to work in Svelte 4.

Reproduction

https://svelte-5-preview.vercel.app/#H4sIAAAAAAAAA6tWSsvMSS1WsoquVspLzE1VslJyLChQ0lEqqSwAcYrLUnNKUoH84vzSomSQiE1xclFmQYldTF5MSWZuQX5RiYLz4WUXtp3b-GDJ1MfNm5_sWKuQVpSfqxCjpKePLqMHMS9GyRqkPSe1RAFkqYItUHF5flFOCljCRh9hRZ5NZl5BaYlCUmZeilVZYk5pqm01SEutgj5Q2gbDZiRJoKNz81My0zJTU5SsSopKU2t14H5E10esh1MrwB6GORzDsRmGdh6pOTn5UHco2ugDRbA5JbYWAOLILSp6AQAA

Logs

N/A

System Info

N/A

Severity

annoyance

[dummdidumm]

This was changed in #13057. The idea was to disallow obviously-wrong characters, like [. We didn't take into account other alphanumeric characters outside the "obvious" range though. I would be in favor of widening that.