I have tried to solve this with the following steps suggested by Dimitris Bouzikas:
1. Quit Xcode.
2. Delete project's temp files located at ~/Library/Developer/Xcode/DerivedData
3. Delete ProjectName.xcworkspace
4. Delete Podfile.lock file and Pods folder
5. Run pod install.
6. Open the newly created ProjectName.xcworkspace file and build.
It doesn't work out.
Attemp 2
Well. Then i looked at the second answer suggested:
Build (⌘ + B) worked for me
Interestingly, I can build and run but the warning was still there.
Solution: Manage Schemes and select it
Here is the third answser suggested which finally works for me.
Previously, I have encountered this warning after installing RealmSwift by cocoapod I have solved this with the suggestion on Error: Could not build Objective-C module 'Firebase'
Attemp 1
I have tried to solve this with the following steps suggested by Dimitris Bouzikas:
It doesn't work out.
Attemp 2
Well. Then i looked at the second answer suggested:
Interestingly, I can build and run but the warning was still there.
Solution: Manage Schemes and select it
Here is the third answser suggested which finally works for me.
Manage Schemes and select it.
Then the warning has gone away.