There are further enum layout optimization implemented: https://github.com/rust-lang/rfcs/issues/1230 https://github.com/rust-lang/rfcs/issues/1230, or is being

There are further enum layout optimization implemented: https://github.com/rust-lang/rfcs/issues/1230 https://github.com/rust-lang/rfcs/issues/1230, or is being worked: https://github.com/rust-lang/rust/issues/46213 https://github.com/rust-lang/rust/issues/46213. These simple ideas on the surface sometimes can be very hard to implement in reality due to various compiler internal complexity. It is fascinating that these ideas are getting implemented in rustc so that we see tangible benenfits in real life.