Next.js 12.0.8 breaks "this" in TS classes

[VladimirMikulic]

Run next info (available from version 12.0.8 and up)

Operating System:
Platform: linux
Arch: x64
Version: #51~20.04.1-Ubuntu SMP Fri Jan 7 06:51:40 UTC 2022
Binaries:
Node: 16.13.2
npm: 8.0.0
Yarn: 1.22.17
pnpm: N/A
Relevant packages:
next: 12.0.8
react: 17.0.2
react-dom: 17.0.2

What version of Next.js are you using?

12.0.8

What version of Node.js are you using?

16.13.2

What browser are you using?

Chrome, Safari, Firefox

What operating system are you using?

Android, IOS, macOS, Windows, Linux

How are you deploying your application?

Vercel

Describe the Bug

After upgrading Next.js from 12.0.7 to 12.0.8, an important system broke at our company.
TypeScript code that had classes like the example below broke, because this became undefined.
(check out "To Reproduce" section)

Expected Behavior

I would expect this in a method to actually refer to the instance of the class and not be undefined.
(as also specified in TS docs)

This code has been in the codebase for quite a while and has survived major Next.js releases, until this minor one :)

To Reproduce

// example.ts
export default class Example {
  readonly status: string;

  constructor({ status }: { status: string }) {
    this.status = status;
  }

  public activate = async (data: string) => {
    // Some code...
    this.status // WHOOPS! Exception thrown - this undefined! (worked fine in 12.0.7)
  };
}

// index.ts
const example = new Example({ status: "GOOD" })
example.activate("some string");

[balazsorban44]

This issue has been automatically locked due to no recent activity. If you are running into a similar issue, please create a new issue with the steps to reproduce. Thank you.