Error Xcode 6 --> Error SourceKit terminated. Editor functionality temporarily limited [duplicate]

Answer 1

an update released in Dec 2, 2014, related to this error.

Please make sure your xcode latest.

Xcode, Apple Version 6.1.1 Released Dec 2, 2014
Includes SDKs for OS X 10.10 Yosemite, OS X 10.9 Mavericks, and iOS 8.1

 - Fixed common causes of SourceKit crashes when working with Swift
 - Additional bug fixed and stability improvements