Eval function breaks async function (name conflict)

[ambar]

Describe the bug

There's a eval call after two async functions in file-type@16:

https://github.com/sindresorhus/file-type/blob/b5fe3b9596711a42c0141d97a11e4f0fa5fcc7a0/core.js#L1417-L1419

swc generates two _fromTokenizer functions, which are considered invalid in ESM:

Identifier '_fromTokenizer' has already been declared

Input code

async function fromTokenizer() {}
async function _fromTokenizer() {}
eval()

Config

{
  "jsc": {
    "externalHelpers": true,
    "parser": {
      "syntax": "ecmascript",
      "jsx": false
    },
    "target": "es5",
    "loose": false,
    "minify": {
      "compress": false,
      "mangle": false
    }
  },
  "module": {
    "type": "es6"
  },
  "minify": false,
  "isModule": true
}

Playground link

https://play.swc.rs/?version=1.3.14&code=H4sIAAAAAAAAA0ssrsxLVkgrzUsuyczPU0grys8Nyc9OzcusSi3S0FSoruVKRFURj0VJallijoYmFwCmDQFwTAAAAA%3D%3D&config=H4sIAAAAAAAAA0WOSw7DIAxE7%2BI123bBCbrpISzqRFT8ZDtSEOLuhYgq25k3T9PgKw5sAzqVOGF4USjEAlb5IAMFWYgnIDUpnmCBXERx7IuCGesRbRiEugFF3kknIo%2FRhZyFVmsg%2BuS3Ok0ux8IkcleY9vAn%2BxDF%2FDlm0EBroUv4hH471s7Le4HzbP8Bh3dPJ8wAAAA%3D

Expected behavior

The transform works correctly, and the function names do not conflict.

Actual behavior

Module parse error.

Version

1.3.14

Additional context

No response

[kdy1]

#5068

[swc-bot]

This closed issue has been automatically locked because it had no new activity for a month. If you are running into a similar issue, please create a new issue with the steps to reproduce. Thank you.