What the borrow checker won't review

A recurring theme on this blog is handing your code to a compiler and letting it find the bug. I still believe in that. But I spent last week on bcachefs (swap files on a copy-on-write filesystem, and the hardening that keeps them from deadlocking) and I want to be honest about where “let the compiler review it” runs out. It’s a live question for the project, not a rhetorical one. bcachefs is in…