[This error in the image below occurs when trying to build the app.] (https://i.sstatic.net/QibXK.png)
Note: In pub.dev firebase_ui_firestore there is the same error pointed out!
I have tried flutter clean
and flutter pub get
which gave no positive result.
In pubspec.yaml, replace firebase_ui_firestore: 1.6.0 with:
firebase_ui_firestore:
git:
url: https://github.com/firebase/FirebaseUI-Flutter.git
path: packages/firebase_ui_firestore
They have fixed it but version is not published yet.