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

Cleaning the project wasn't working for me, this is because I didn't pay attention to the message right above (Xcode highlights only the final command).

In my case it was

<unknown>:0: error: filename "FileDuplicated.swift" used twice: '/../filepath/FileDuplicated.swift' and '/../filepath/FileDuplicated.swift'
<unknown>:0: note: filenames are used to distinguish private declarations with the same name
Command /../bin/swiftc failed with exit code 1

I had to change the name of one of the two files and it was solved.

Hope this can help someone, cheers

Answer 2

delete Derived Data folder and Build it.

Go to Xcode -> Preferences -> Locations for get the derived data path or cmd+Alt+shift+k

OR

Just remove inactive file(deleted file) from Build phases

Answer 3

Ok, my turn now. In my case I had an existing project. I copied in a few files from another project. One of the files I brought in was SettingsViewController.swift and there was already a file by the same name I was not aware of. The files were in different directories of the project so no duplicate message was shown. The compile/link messages offered no clue to this. I figured out the issue by adding one file at a time to the project (there were 12 total) and the building each time until I found the offending file. I renamed the new file and project builds now.

Answer 4

In my case it was due to the few swift files which has been showed grayed out in the Build Phases section. After removing those files it was successful.

Answer 5

1. Clean the build in Xcode cmd+shift+k.
2. Update the pods.
3. look the where errors showing.
4. Add the missing files in Xcode.
5. After Run the Code. Working fine.

Answer 6

Have you tried to do clean with Clean build folder?

The combination keys is:

ALT + SHIFT + COMMAND + K