Rust uses RAII and ownership/borrowing for safe, performant memory management (no GC). At the same time, it doesn't automatically use memory. So, stuff goes on the stack unless I explicitly put it inside a heap-based thing (e.g. a box or a vector). These things clean up after themselves and can be used cleanly.
At the same time, since you don't have to use the heap, and low level code isn't too hard to write in Rust, you can easily write non-allocating OS-level code if you wish. And with the appropriate (unsafely implemented, but verifiable) zero-cost abstractions, you can still have safe code at this level.
For some definition of "have to" and "manual".
Rust uses RAII and ownership/borrowing for safe, performant memory management (no GC). At the same time, it doesn't automatically use memory. So, stuff goes on the stack unless I explicitly put it inside a heap-based thing (e.g. a box or a vector). These things clean up after themselves and can be used cleanly.
Like Sam said here (https://news.ycombinator.com/item?id=10711997), "You have to think about it. You don't have to worry about it."
At the same time, since you don't have to use the heap, and low level code isn't too hard to write in Rust, you can easily write non-allocating OS-level code if you wish. And with the appropriate (unsafely implemented, but verifiable) zero-cost abstractions, you can still have safe code at this level.