Incorrect `new.target.prototype` transformation

[barclayadam]

Describe the bug

In Vite 8.0.0-beta.15, new.target.prototype is incorrectly transformed to _vite_importMeta.prototype in Web Worker contexts, causing a runtime TypeError when the code executes.

Source code:

Object.setPrototypeOf(this, new.target.prototype);

Built output (Vite 8 beta.15):

var _vite_importMeta = { url: self.location.href };
// ...
Object.setPrototypeOf(this, _vite_importMeta.prototype); // ❌ _vite_importMeta.prototype is undefined!

Reproduction

https://stackblitz.com/edit/ak5xqjbd?file=vite.config.ts,index.html,README.md

Steps to reproduce

npm run build OR npm run preview. Details in README.md

System Info

System:                                                                                                            │
  │     OS: Windows 11 10.0.26100                                                                                        │
  │     CPU: (22) x64 Intel(R) Core(TM) Ultra 7 165H                                                                     │
  │     Memory: 11.00 GB / 63.46 GB                                                                                      │
  │   Binaries:                                                                                                          │
  │     Node: 24.7.0 - C:\Program Files\nodejs\node.EXE                                                                  │
  │     npm: 11.5.1 - C:\Program Files\nodejs\npm.CMD                                                                    │
  │     pnpm: 10.24.0 - C:\Users\AdamBarclay(Symprex)\AppData\Local\Microsoft\WinGet\Links\pnpm.EXE                      │
  │     bun: 1.3.3 - C:\Users\AdamBarclay(Symprex)\AppData\Local\Microsoft\WinGet\Links\bun.EXE                          │
  │   Browsers:                                                                                                          │
  │     Chrome: 145.0.7632.116                                                                                           │
  │     Edge: Chromium (140.0.3485.54)                                                                                   │
  │     Firefox: 145.0.2 - C:\Program Files\Mozilla Firefox\firefox.exe                                                  │
  │     Internet Explorer: 11.0.26100.7309                                                                               │
  │   npmPackages:                                                                                                       │
  │     vite: 8.0.0-beta.15 => 8.0.0-beta.15

Used Package Manager

npm

Logs

No response

Validations

• Follow our Code of Conduct
• Read the Contributing Guidelines.
• Read the docs and the Rolldown-related guide.
• Check that there isn't already an issue that reports the same bug to avoid creating a duplicate.
• Check that this is a concrete bug. For Q&A open a GitHub Discussion or join our Discord Chat Server.
• The provided reproduction is a minimal reproducible example of the bug.

[sapphi-red]

This is fixed since Vite 8.0.0-beta.17.