[btown]

That's a very intriguing block of code there. I'd like to think that while Rust may not have been designed to guarantee that leaks are prevented, it so happens that anything that could leak memory sticks out like a sore thumb in code review, since the code to get something to leak needs to be explicit. I'd consider a global variable or a channel that has the possibility of not reading all its values to follow that pattern. Whereas it's much easier to get something "stuck" in memory without a reference in C++. But you're absolutely right that memory safety does not at all imply "leak" safety, nor is the latter well defined at all!