miniblog.

I find test coverage a useful thing to track, but I can't find a good metric. "Coverage decreased by 10%" sounds bad. If you're deleting pointless code that has tests, it's good! Perhaps total untested lines of code is better?

Clippy has a ton of clever lints I haven't seen before. E.g. it suggests that `let _v = println!("hello");` could be `println!("hello");` because a variable of type () is pointless. Warning about recursion in main is an excellent idea too.

Smalltalk shows a lint error if you recurse unconditionally: you've basically written a pointless infinite loop. I've not seen lints for this elsewhere, but it's a really nice touch.