modules are meant to be the boundary for a safe abstraction, but sometimes you get fun holes like https://github.com/rust-lang/rust/issues/128872 https://github

modules are meant to be the boundary for a safe abstraction, but sometimes you get fun holes like https://github.com/rust-lang/rust/issues/128872 https://github.com/rust-lang/rust/issues/128872 where you can implement Copy for a type in a different module in the same crate, even if the fields are private