I didn't take it that way; he said Rust was a very interesting language. It seems like he believes pervasive borrow checking is not the right approach for the

I didn't take it that way; he said Rust was a very interesting language. It seems like he believes pervasive borrow checking is not the right approach for the average application developer, even if it is the right approach for systems programming. He also mentioned eventually having a mode that only uses borrow-checking without ARC, e.g. for writing firmware. Rust originally had lofty goals to support compile-time lifetime proving and GC mode; GC was abandoned for sensible reasons. Swift uses ARC, so it is trying to support full-ARC, mixed mode, and compile-time lifetime. Whether that is achievable remains to be seen.