Panic on invalid code

[marvinhagemeister]

Describe the bug

SWC panics when it encounters this particular source that is invalid JS. The error can be reproduced in the SWC playground.

Originally reported at denoland/deno#24417

Input code

https://fake.com

interface Fake {
}

Config

No response

Playground link (or link to the minimal reproduction)

https://play.swc.rs/?version=1.6.7&code=H4sIAAAAAAAAA8soKSkottLXT0vMTtVLzs%2Fl4srMK0ktSktMTlVwA4opVHPVAgDVU9KdJAAAAA%3D%3D&config=H4sIAAAAAAAAA1WQPQ7CMAyFd05ReWZAHRi4AxMnsIJbBTU%2Fsh2JCvXuJOn%2FEiXfe8%2BO%2Fbs0DXzEwKP55Wt%2BRGQh3t6ZyOgVv5mAjpHEsI0K11VVKZJyokqmWQBF7klLiKS9te0SgCEEoYw7HIQW5qy33XhsaYKLTCJnY7Gi74ctf%2B7I6KUL7I6FmNDoAWRkXQysr5DYlELgo3vMtutu4uTVuqpj0uBQrYFFni7rWVuDC%2B9U%2F7RssGxpHvwOu2mdcZsHrDzXZF3f9Ae8XWptjQEAAA%3D%3D

SWC Info output

No response

Expected behavior

SWC should not panic

Actual behavior

No response

Version

1.6.8-nightly-20240704.3

Additional context

No response

[CPunisher]

From the AST of the code:

"body": [
    {
      "type": "LabeledStatement",
      "span": {
        "start": 0,
        "end": 36,
        "ctxt": 0
      },
      "label": {
        "type": "Identifier",
        "span": {
          "start": 0,
          "end": 5,
          "ctxt": 0
        },
        "value": "https",
        "optional": false
      },
      "body": {
        "type": "TsInterfaceDeclaration",
        "span": {
          "start": 18,
          "end": 36,
          "ctxt": 0
        },

The TsInterfaceDeclaration within the LabeledStatement cannot be removed during StripType, thus it will be visited and trigger an unreachable panic (Code).

I attempted to change unreachable_visit_mut_type!() to noop_visit_mut_type!(), but it triggered the standard_only_visit_mut!() panic(Code) of the RegExp Visitor(maybe other visitors).

Perhaps there are two possible solutions:

1. Patch StripType to remove every TsInterfaceDeclaration. This is how tsc do, and its compilation result is:

https: ;

2. Do not remove TsInterfaceDeclaration and find a way to resolve the subsequent panic. This may be how oxc do(no panic), and its compilation result is:

https: interface Fake {}