Strip-types handing async arrow with multi-line type parameter

[acutmore]

Describe the bug

Using @swc/wasm-typescript (strip-types mode), with input that contains an async arrow function that also has a type parameter that spans multiple lines the output JavaScript includes a syntax error.

Input code

let f = async <
   T
>(v: T) => v;

Config

{
  "jsc": {
    "parser": {
      "syntax": "typescript",
      "tsx": false
    },
    "target": "es2022",
    "loose": true,
    "minify": {
      "compress": false,
      "mangle": false
    }
  },
  "module": {
    "type": "es6"
  },
  "minify": false,
  "isModule": true
}

Playground link (or link to the minimal reproduction)

https://play.swc.rs/?version=1.7.40&code=H4sIAAAAAAAAA8tJLVFIU7BVSCyuzEtWsOFSUFAI4bLTKLNSCNFUsLVTKLPmAgD0%2BerKIwAAAA%3D%3D&config=H4sIAAAAAAAAA1WPSw7DIAxE9zkF8rqLikUXvUMPgagTUfETdqSiKHcvJEDbHZ5h%2FMbbJAS8SMNdbOVZhqgSYRpzUSh7Vu%2BiAOeIpJOJDJfuMlVrVpbwkPbTAVZpQa4pJHmVsiXAhkBYZE4rNskZb%2Bb8i9TBxYREffOgOeUXi%2F%2FAqUHBhed6mO2UWvcscIPvpw4bi8HQoydrq2n%2FALtj80kWAQAA&strip-types=

SWC Info output

N/A

Expected behavior

The output to not contain a new line after the async keyword. e.g:

let f = async ( 
    
  v   ) => v;

Actual behavior

let f = async  
    
 (v   ) => v;

Version

1.7.40

Additional context

This edge case was originally found by @seralexeev and reported on ts-blank-space which hit the same issue: bloomberg/ts-blank-space#19

[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.