Question posted in 
When debugging for iOS with Flutter, the following error occurs during build.
Lexical or Preprocessor Issue (Xcode): Include of non-modular header
inside framework module
‘firebase_storage.FLTTaskStateChannelStreamHandler’:
‘/Users/User1/FlutterProjects/flutter_project/ios/Pods/Headers/Public/Firebase/Firebase.h’
/Users/User1/.pub-cache/hosted/pub.dev/firebase_storage-11.7.7/ios/Classes/FLTTaskStateChannelStreamHandler.h:12:8
env
Xcode 16,
iOS Simulator 17.5 and 18.0
Flutter 3.24.2 • channel stable • https://github.com/flutter/flutter.git
Framework • revision 4cf269e36d (2 weeks ago) • 2024-09-03 14:30:00 -0700
Engine • revision a6bd3f1de1
Tools • Dart 3.5.2 • DevTools 2.37.2
2
Answers
This helped me to solve it, I hope it helps you too.
#12962
This came from an answer already posted, but there was a part missing in the GitHub issue I didn’t get at first.
To fix this you need to Open Xcode and set Allow non-modular Includes In Framework Modules to Yes.
Xcode setting to change
You can do this by:
This cleared up the issue and my app was able to be built and launch on the simulator.