xcode intellisense/autocomplete stopped working - How to bring it back?

While doing swift code in Xcode the intenseness suddenly stopped working. How do I bring it back?

Here are few things you can try -

• Restart the Xcode - you may get lucky and it may start working
• Next option - Start with Command + Shift + Key and clean the project
• If its still not working, now we are going little detail, go to /Users/Library/Developer/Xcode/DerivedData
• Find your project directory for which its broken, delete the content of the folder
• Other way to do the same is from Xcode, go to Windows > Organize > Delete the Derived data
• Delete the ModuleCache folder content from the 
  /Users/Library/Developer/Xcode/DerivedData and restart the Xcode, it should come up fine.

Good luck with the fix, let me know if it works or if I should add any additional technique to handle this.