You can use Rust references that way to some extent, although the safety check for references will probably prevent you from using it to do what you want in all cases. In general, you need to follow a stack discipline with your references. For example, you can't make a doubly linked list using unique smart pointers and references as the backpointers; the Rust compiler will be unable to prove it safe. (In general, while placing references inside data structures can be done, it requires some knowledge of the how the safety check works—this is where the "lifetime parameters" come in.)

The good news is that the Rust compiler does detect and clean up cycles of `@` smart pointers. At the moment, this is done at thread death only. But Graydon is nearly done with a new tracing garbage collector (written in Rust) that correctly detects and cleans up cycles.