After installing Xcode 7 to play with Swift 2 in Playgrounds, I've got a weird problem:
when I open an existing Xcode 6.3 project with Xcode 6.3, it throws lots of errors about conversions to Swift 2.
This project was just cloned from the repository and hasn't been opened with Xcode 7 yet.
So my guess is that the Xcode 7 install messed up the Xcode 6.3 installed tools or something like that, but I have no idea how I could start to fix this.
I certainly don't want to open and upgrade this big project in Xcode 7 at the moment, but I do need to open it in Xcode 6.3 and Swift 1.2 to continue work on it.