You're not using Xcode. I mean Really Using Xcode. Like making a serious attempt at exercising its features. Hell, you really don't even have to do that. Create a project, edit some code, compile and run your app. That's usually fine. Now, try repeatedly, several times a minute for eight hours straight to use the debugger on your app (intentionally overrelease something or create some other reason for Xcode to launch lldb when your app crashes.)

Xcode will crash.