I'm getting “clang: error: no input files”

Question

I had a file which I deleted and replaced with another file, somewhere else, of the same name.

Despite cleaning, and trying this multiple times, I keep getting this

Answer 1

Additional to all answers:

1. delete derived data
2. reboot
3. delete derived data
4. clean
5. build
6. Success!

Only this sequence works for me in my case.