Also, the code inside the else{} block is required to leave the current scope (e.g. return from the method, fatalError(), assert(false), etc.). In that way, 'x'

Also, the code inside the else{} block is required to leave the current scope (e.g. return from the method, fatalError(), assert(false), etc.). In that way, 'x' will always contain a valid value after the guard statement, or statements after the guard statements will not execute.