While installing a cocoa pod, I ran into this hideous and misleading error:
“Use Legacy Swift Language Version” (SWIFT_VERSION) is required to be configured correctly for targets which use Swift. Use the [Edit > Convert > To Current Swift Syntax…] menu to choose a Swift version or use the Build Settings editor to configure the build setting directly.
A long stroll around stackoverflow and the cocoapods github issues forums showed me many solutions, but none was simple and straightforward.
So I just read the whole error again, and saw the "Or......" part, and followed it with a bit of improvisation.
Here's how to solve this error:
1. click the "pods" project in your xcode workspace
2. select the target of the pod that generated this issue
3. go to its build setting and search for "SWIFT_VERSION"
4. find the field "Use Legacy Swift Language Version" - and set it to "No"
5. clean, (maybe delete derived data), build - and you're fine :)
I hope you find this helpful to solving this error with cocoapods and swift 3 on xcode 8