Swift 3 "default can only appear in a switch statement"

Xcode 8.3.3, just converted my project's target to Swift 3, still getting this error "default can only appear in a switch statement"

let urls = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)

Swift wrong compile error: default label can only appear in switch statement

I tried with the backticks too but that didn't work. How do I compile this?