I'm not claiming Swift 3.0.2 is the most reliable language ever. All systems require time to mature and it is very young historically speaking. I am saying Lattner's design principles should realize better results for safety-critical software in the long run. Compiler bugs can be fixed; programmer error is tied to design. It might be Swift, it might be something more pared down, but he's a good guy to have in charge of an autonomous driving software platform.