Rust doesn't tend to leak memory, but it doesn't make any firm guarantees about memory leaks as opposed to invalid accesses. For example, even in perfectly safe

Rust doesn't tend to leak memory, but it doesn't make any firm guarantees about memory leaks as opposed to invalid accesses. For example, even in perfectly safe Rust code, you can make a cycle out of reference-counted smart pointers, and their destructors will never run. So valgrind may be useful for that, and it's common to interact with C libraries which may leak memory. But it's much less common to need than it is in the C/C++ worlds.