Assigning to rvalue `svelte(js_parse_error)`

[ottomated]

Describe the bug

With this code:

foo! += 1;

(which is valid typescript)

Svelte throws Assigning to rvalue svelte(js_parse_error)

Reproduction

REPL

Logs

No response

System Info

svelte@5.0.0-next.259

Severity

annoyance

[paoloricciuti]

I'm 99% sure it's an upstream bug in acorn-typescript

[paoloricciuti]

Confirmed, opened an issue there

TyrealHu/acorn-typescript#64

[webJose]

acorn-typescript seems to be abandoned.