Comment by efficax

I suppose all languages allow them, depending on how you define a memory leak. Garbage collected languages generally prevent them, since you never have to explicitly free memory, but if there are reference cycles, that memory can never be freed automatically. Rust has the same problem, but since rust uses lifetimes to understand when to drop things, many people expect that this will mean there can be no memory leaks, but leaks are not considered a correctness or safety issue (oom is a panic and panic is safe!). Not only explicitly possible (through Box::leak) but also possible by mistake (again, usually through reference cycles).