`Box::new(x)` seems to compile to exactly the same assembly as `box x` in release mode: https://play.rust-lang.org/?gist=55ec5dd02c22fa799375d6e2e1a6e970&version=nightly Source-Repo: https://github.com/servo/servo Source-Revision: fc4de5adf5bff7fabe9f32b960c405f249b5d035