Flutter：类型'Future<bool>'不是类型'bool'在类型转换中的子类型

我试图根据返回的值显示一个小部件。但得到以下错误。

type 'Future<bool>' is not a subtype of type 'bool' in type cast
以下是导致错误的源代码。
  Future<bool> fetchCourses() async {
    List courses = [];
    final loggedInUser = FirebaseAuth.instance.currentUser;
    if (loggedInUser != null) {
      final userCollection = await FirebaseFirestore.instance.collection('users').doc(loggedInUser.uid).get();
      courses = userCollection.get('coursesEnrolled');
    if (courses.length == 0) {
      return false;
    } else {
      return true;
bool hasCourses = fetchCourses() as bool;
hasCourses ? ListAllUserEnrolledCourses() : Container(),