We used to have `#![deny(unused)]` in Servo, and it was quite annoying. Especially because a compile takes a while and the lints run mid-compile (after type/bor

We used to have `#![deny(unused)]` in Servo, and it was quite annoying. Especially because a compile takes a while and the lints run mid-compile (after type/borrow check but before the llvm stuff). Quite annoying, eventually we turned it off. But it wasn't so bad; because when writing Rust code there's more fixing of type/borrow errors and less waiting for a full compile and running tests; since most of the "correctness" is encoded in the types used.