fatal error: module 'cloud_firestore' not found

you are missing firebase_core

dependencies:
  flutter:
    sdk: flutter
  firebase_core: ^0.5.0
  cloud_firestore: ^0.14.0+2

check this official guide for more: Cloud Firestore

Trust me, I search for over 5 hours, tried every solution I can find on internet. And only one work:

1. Delete the Podfile, Podfile.lock, Pods folder
2. flutter clean
3. cd ios
4. pod deintegrate ( this way pod will not reinstall the old libray )
5. cd ../
6. flutter run

Most of the solution don't include step 4, so that why even you clean and reinstall pod, it still behave the same. At the developer, we can learn how to reverse the binary tree in 2 hour and struggle with install steps for over a day, one of the most annoying thing of being developer.