Swift Error: Editor placeholder in source file
Solution 1:
Sometimes, XCode does not forget the line which had an "Editor Placeholder" even if you have replaced it with a value. Cut the portion of the code where XCode is complaining and paste the code back to the same place to make the error message go away. This worked for me.
Solution 2:
After Command + Shift + B, the project works fine.
Solution 3:
Go to Product > Clean Build Folder