The “Swift Language Version” (SWIFT_VERSION) build setting must be set to a supported value for targets which use Swift.

今天尝试写一个MVVM+RAC的demo，项目中用pod引入ReactiveCocoa后运行报错：
The “Swift Language Version” (SWIFT_VERSION) build setting must be set to a supported value for targets which use Swift. This setting can be set in the build settings editor.
解决办法如下：

swiftVersion.png

分别选中TARGETS里的ReactiveCocoa、ReactiveSwift、Result, 将Swift Language Version选项改为Swift 4.0即可