ts error when using MatchRoute to identify parametrized child route in the parent route component

const PostsComponent = () => {
  return (
    // show clickable list of posts
    // ...
    
    // render additional elements when detailed post view route /posts/$postId opened. Getting ts error that `postId` param is not specified
    <MatchRoute to="/posts/$postId">
      <p>I am rendered when /posts/$postId child route is active</p>
    </MatchRoute>

    <Outlet /> // used to represent detailed post view
  );
}

const PostComponent () => ... // shows single post details

// create a router
const rootRoute = createRootRoute();

const indexRoute = createRoute({
  getParentRoute: () => rootRoute,
  path: '/',
  component: () => <Navigate to="/posts" />,
});

const postsRoute = createRoute({
  getParentRoute: () => rootRoute,
  path: 'posts',
  component: PostsComponent,
});

const postRoute = createRoute({
  getParentRoute: () => postsRoute,
  path: '$postId',
  component: PostComponent
});

const routeTree = rootRoute.addChildren([
  indexRoute,
  postsRoute.addChildren([postRoute]),
]);