> The temp allocator implementation isn't guaranteed to detect it, and the article doesn't go into implementation details and guarantees

Understandable, but then why are you mentioning the borrow checker if you avoided mentioning _anything_ that could be compared to it.

> No, there is no guarantee at the language level

Then don't go around claiming they are statically checked, that's false. What you have is a basic linter, not a statically enforced contract system.