As of Rust 2018, macro_use is no longer required in most circumstances. I think it is generally a good idea to remove these when not needed, to stop them from polluting the crate's global namespace. https://doc.rust-lang.org/edition-guide/rust-2018/macros/macro-changes.html#macro_rules-style-macros
1.81% -> 0.56%
From 1.03% to 0.19% of the runtime of 'nix-instantiate "<nixpkgs>" -A texlive.combined.scheme-full --dry-run'.