```js // @filename: mod1.js var Workspace = {} Workspace.Project = function () { } Workspace.Project.prototype = { isServiceProject() { } } // @filename: test.js /** @param {Workspace.Project} p */ function demo(p) { p.isServiceProject() } ``` Expected: no error, and `p.isServiceProject(): void`. Actual: no error if you compile `tsc mod1.js test.js`, but an error with `tsc test.js mod1.js`: Property 'isServiceProject' does not exist on type 'typeof Project'. From chrome-devtools-frontend, failed in https://github.com/microsoft/TypeScript/pull/34603