As the title suggests, I was trying to add a flutter module app to an existing app following the official guide https://github.com/flutter/flutter/wiki/Add-Flutter-to-existing-apps

Everything runs fine up to the final point where I try to build the iOS app and it complains about

ld: warning: directory not found for option '-F/some/path/flutter/build/ios/Debug-iphonesimulator/FlutterPluginRegistrant'

I checked the intermediary build folder and wasn't able to find FlutterPluginRegistrant, my guess is the FlutterPluginRegistrant pod wasn't updated to have the right build settings?

It's really too big of a file to upload for a minimal demo setup. But happy to if its needed for further discussions. What I did was really just following the guide.

Running softwares are:
XCode: 10.0 and 10.1 both failed
CocoaPods: 1.6.1
Flutter: 1.2.1
OSX: 10.14.2