You really need to lay your code in away that will satisfy the checkers. But that becomes a second nature after a while. I think all the edge cases that still

You really need to lay your code in away that will satisfy the checkers. But that becomes a second nature after a while. I think all the edge cases that still exist make it more problematic. E.g. I was writing some SIMD code yesterday with a loop somewhat like this (simplified): let mut v = vec![1.0, 2.0, 3.0, 4.0, 5.0, 6.0]; let mut s: &mut [f32] = &mut v; while s.len() >= 2 { println!("{:?}", s); s = &mut s[2..]; } Playground: https://play.rust-lang.org/?gist=104348b0edb96ca0f68d701373eca7fa https://play.rust-lang.org/?gist=104348b0edb96ca0f68d701373e... It makes you scratch your head for a bit. A good example of the challenge is that there's unsafe inner code in rusts own container code. I am pretty proud that one of my first small Rust projects was a randomized ternary trie. Apparently, it does not use unsafe anywhere. https://github.com/danieldk/rtrie/blob/master/src/ternary.rs https://github.com/danieldk/rtrie/blob/master/src/ternary.rs Not that I am proud of the code ;). But in all seriousness, unsafe in container code is somewhat expected, because at some point you need to wrap raw memory (as e.g. in Vec). I think quite a bit of, but probably not all, unsafe use in containers such as Vec comes from that.