dcz, 
A part of #Rustlang that doesn't get mentioned but is a ridiculous quality of life boon:
dbg!()
Just #[derive(Debug)] on a struct and print it. Suddenly you get insight into what's going on. Very rarely do you need to write your own print.
Insert a dbg in the middle of anything
let diffi = debug!(diffs).iter();
and you get a message with line number and the name of variable:
[src/lib.rs:192:19] diffs = [16, 86, 11]
Not even #Python has that!
