A problem with Rust is changes to types can require widespread changes throughout a codebase, but it does not obviously seem to have refactoring tools such as some other languages where type strongly influences interface do. I have a file containing roughly 89 closures, each of which need to now be changed from |eval, args| where eval has a member "memory" to |eval, memory, args|. This will be… slow. My carpal tunnels will not be happy.