Command CompileSwift failed with a nonzero exit code in Xcode 10 [duplicate]

Answer 1

Class re-declaration will be the problem. check duplicate class and build.

Answer 2

I got this randomly since Xcode 10. I think it occurs when I change something in the code while building starts. The next build works every time.

Answer 3

I attempted

• Closing & Reopening Xcode
• Cleaning Build Folder
• Running pod install --repo-update

and all of these still did not fix the problem.

Restarting the Mac did the trick!

Answer 4

My problem was I had due to the non-existence of a native Swift CommonCrypto, used a bridging header and a target that with some magic included it in the build. Since CommonCrypto is now native, I solved the problem by removing the target and the #import and instead added an import CommonCrypto where I used it.

Answer 5

Running pod install --repo-update and closing and reopening x-code fixed this issue on all of my pods that had this error.