Number boxing deserves a mention as well: sometimes even code that might appear to be adequately type-hinted may be performing boxing under the hood.

This can be detected by compiling a codebase with `unchecked-math :warn-on-boxed`.

Unfortunately many libs will emit boxed math warnings, so it isn't particularly easy to fail a CI build on this basis.

Still one can run the checks from time to time, and fix anything that can be fixed.