Incorrect error lines reported when using vi.mock in browser mode

Describe the bug

Using vi.mock in browser mode causes the reported error lines to be incorrect when the test fails

Reproduction

Repo with reproducible behaviour

https://github.com/omricundangan/vitest-demo-errolines
Repo readme has exact steps on how to reproduce the error

Steps

In a clean install of vite (npm create vite@latest) configured for Javascript + React and vitest browser with playwright (npx vitest init browser), create two files: one module, and one testing + mocking the module:

performOp.js:

export const performOp = (a, b) => {
  return a + b
}

performOp.test.js:

import { expect, it, vi } from "vitest"
import { performOp } from "./performOp"

vi.mock('./performOp', () => ({
  performOp: vi.fn().mockReturnValue(10),
}))

it('tests performOp module', () => {
  expect(performOp(1, 2)).toBe(5)
})

Run vitest --workspace=vitest.workspace.js to produce the following output and observe the incorrect error lines reported:

Comment out/remove the vi.mock() segment, to fix and observe the correct error report:

System Info

System:
    OS: macOS 15.3
    CPU: (12) arm64 Apple M3 Pro
    Memory: 173.53 MB / 36.00 GB
    Shell: 5.9 - /bin/zsh
  Binaries:
    Node: 22.9.0 - ~/.nvm/versions/node/v22.9.0/bin/node
    npm: 10.8.3 - ~/.nvm/versions/node/v22.9.0/bin/npm
  Browsers:
    Chrome: 133.0.6943.127
    Safari: 18.3
  npmPackages:
    @vitejs/plugin-react: ^4.3.4 => 4.3.4 
    @vitest/browser: ^3.0.7 => 3.0.7 
    playwright: ^1.50.1 => 1.50.1 
    vite: ^6.2.0 => 6.2.0 
    vitest: ^3.0.7 => 3.0.7 
    vitest-browser-react: ^0.1.1 => 0.1.1

Used Package Manager

npm

Validations

• Follow our Code of Conduct
• Read the Contributing Guidelines.
• Read the docs.
• 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.

Start with the reproduction repository and its README, then run the two-file performOp.js and performOp.test.js example through the Vitest browser workspace with Playwright. Compare the reported locations with and without the vi.mock block; done means the failing assertion reports the correct error lines when mocking is enabled.