Comment by aw1621107

> however the ability to leak memory is pretty demonstrable, no?

This bug wouldn't be nearly as interesting if it "just" resulted in a memory leak. Memory leaks aren't considered unsafe in Rust because they can't result in UB in the same way as e.g., OOB writes. In fact, there are APIs accessible in safe Rust which explicitly leak memory! [0]

This bug is effectively a use-after-free, which is definitely something that the Rust compiler should catch.

> Would be cool to see clippy pick up on this bug in older versions!

No need for that. A future version of the Rust compiler that incorporates a fix should reject the incorrect code, so all you'd need to do is compile older code with that new compiler.

[0]: https://doc.rust-lang.org/std/mem/fn.forget.html