Changed types for extending matchers

[dosolkowski-work]

Describe the bug

Similar to #6660, it looks like the Assertion<T> type is being found in @vitest/expect now instead of vitest itself. This changed from v2.1.2 to v2.1.3. As a result, the Extending Matchers documentation on Vitest's own website no longer works; TypeScript will not find the custom matcher functions. If this change is desired, please update the documentation on the website to match.

Reproduction

The code in Extending Matchers no longer works as-is. Instead, it must be changed to the following:

import '@vitest/expect'

interface CustomMatchers<R = unknown> {
  toBeFoo: () => R
}

declare module '@vitest/expect' {
  interface Assertion<T = any> extends CustomMatchers<T> {}
  interface AsymmetricMatchersContaining extends CustomMatchers {}
}

In addition, depending on the package manager setup, it may be necessary to add a package reference to @vitest/expect.

System Info

System:
    OS: Windows 11 10.0.22631
    CPU: (32) x64 13th Gen Intel(R) Core(TM) i9-13950HX
    Memory: 12.14 GB / 31.61 GB
  Binaries:
    Node: 20.18.0 - C:\Program Files\nodejs\node.EXE
    npm: 10.8.2 - C:\Program Files\nodejs\npm.CMD
    pnpm: 9.12.2 - C:\Program Files\nodejs\pnpm.CMD
  Browsers:
    Edge: Chromium (127.0.2651.74)
    Internet Explorer: 11.0.22621.3527
  npmPackages:
    @vitest/coverage-istanbul: ^2.1.3 => 2.1.3
    @vitest/eslint-plugin: ^1.1.7 => 1.1.7
    @vitest/ui: ^2.1.3 => 2.1.3
    vite: ^5.4.9 => 5.4.9
    vitest: ^2.1.3 => 2.1.3

Used Package Manager

pnpm

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• Read the Contributing Guidelines.
• Read the docs.
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• The provided reproduction is a minimal reproducible example of the bug.

[hi-ogawa]

It's working for me https://github.com/hi-ogawa/reproductions/tree/main/vitest-6761-expect-extend Can you provide a reproduction?

[github-actions]

Hello @dosolkowski-work. Please provide a minimal reproduction using a GitHub repository or StackBlitz (you can also use examples). Issues marked with needs reproduction will be closed if they have no activity within 3 days.

[dosolkowski-work]

I was able to reproduce using a project created from the StackBlitz link: https://stackblitz.com/edit/vitest-dev-vitest-mskyqm