vue3-core/test-dts/reactivity.test-d.ts

import { readonly, describe, expectError } from './index'

describe('should support DeepReadonly', () => {
  const r = readonly({ obj: { k: 'v' } })
  // @ts-expect-error
  expectError((r.obj = {}))
  // @ts-expect-error
  expectError((r.obj.k = 'x'))
})