So it's an interesting thought experiment, but... I suspect the Rust compiler could statically figure this out for a large # of cases .... based on following the borrow/copy/clone tree for any particular variable. It could in theory be possible to write a tool which traces that graph back to the snippets of code where it originates, though that would usually end up being a command-line args parser, or a config file reader...

It's mostly feasible in other languages to, but probably not with the same level of rigor.

Anybody here from JetBrains?