[pull] main from vitest-dev:main

docs/api/assert.md

@@ -2,6 +2,34 @@
 
 Vitest reexports the `assert` method from [`chai`](https://www.chaijs.com/api/assert/) for verifying invariants.
 
+::: warning In-Source Testing {#in-source-testing}
+When using [assertion functions](https://www.typescriptlang.org/docs/handbook/release-notes/typescript-3-7.html#assertion-functions) such as `assert` from `import.meta.vitest` in [in-source tests](/guide/in-source), TypeScript reports error `TS2775` because they must be called via an explicitly annotated name. Annotate the variable with `Chai.Assert` or call it directly:
+
+::: code-group
+```ts [Annotated variable]
+if (import.meta.vitest) {
+  const { test, assert } = import.meta.vitest // [!code --]
+  const { test } = import.meta.vitest // [!code ++]
+  const assert: Chai.Assert = import.meta.vitest.assert // [!code ++]
+
+  test('assert', () => {
+    assert('foo' !== 'bar', 'foo should not be equal to bar')
+  })
+}
+```
+```ts [Direct call]
+if (import.meta.vitest) {
+  const { test, assert } = import.meta.vitest // [!code --]
+  const { test } = import.meta.vitest // [!code ++]
+
+  test('assert', () => {
+    assert('foo' !== 'bar', 'foo should not be equal to bar') // [!code --]
+    import.meta.vitest!.assert('foo' !== 'bar', 'foo should not be equal to bar') // [!code ++]
+  })
+}
+```
+:::
+
 ## assert
 
 - **Type:** `(expression: any, message?: string) => asserts expression`

docs/guide/in-source.md

@@ -152,6 +152,10 @@ To get TypeScript support for `import.meta.vitest`, add `vitest/importMeta` to y
 
 Reference to [`examples/in-source-test`](https://github.com/vitest-dev/vitest/tree/main/examples/in-source-test) for the full example.
 
+::: warning
+There is a limitation when using [assertion functions](https://www.typescriptlang.org/docs/handbook/release-notes/typescript-3-7.html#assertion-functions) such as `assert` in in-source tests. See [`assert`](/api/assert#in-source-testing) for details and workarounds.
+:::
+
 ## Notes
 
 This feature could be useful for: