[pcwalton]

I may be missing something, but what's wrong with the first example? The fact that you can leak an object shouldn't really matter for memory safety if it's just a handle to an object that the server manages. Yeah, it could go wrong, but it won't be unsafe. Object handles are essentially file descriptors, right?

In general I think there's a tendency to overcomplicate safety features in Rust. The solution to an overly-complicated system isn't to throw the whole notion of safety out the window: it's to look at exactly what the complexity is buying you. If intricate combinations of Rust features are one extreme of the safety spectrum and C is the other extreme, there's frequently a happy design medium somewhere in the middle.

Edit: Looks like oconnor663 over on Reddit had a similar but more specific proposal, which probably works: https://www.reddit.com/r/rust/comments/biq864/comment/em2kip...

[Arnavion]

Yes, the same concept is discussed in https://news.ycombinator.com/item?id=19779243