Scratch that, it is actually a planned feature (I thought llvm was already doing it): https://github.com/rust-lang/rust/issues/13707 https://github.com/rust-lan

Scratch that, it is actually a planned feature (I thought llvm was already doing it): https://github.com/rust-lang/rust/issues/13707 https://github.com/rust-lang/rust/issues/13707 The idea is to detect large moves and do a pass by reference, much like Swift does. On my personal roadmap I have detecting these cases and lint against it, suggesting passing the argument as & or &mut as appropriate. That way the performance implications and tradeoffs are visible in the code you write/read.