ERROR “swiftc failed with exit code 1” when converting to latest syntax

Question

I was trying to convert syntax of old Swift project to new one as per few suggestion on Stack Overflow I tried converting it through Edit > Convert > To latest Synta

Answer 1

1. Clean Xcode. (cmd+shift+k)
2. Quit Xcode completely.
3. Open project again.
4. Wait for Xcode to indexing files.
5. Now run your project.