Rust has three different ways of allocating memory. And you can't pass things allocated one way to functions that expect something allocated the other way.
A Python replacement, this ain't. More like C++ on quaaludes.
No, Rust has two ways of allocating memory (on the task heap or on the exchange heap), and most functions take borrowed pointers, which accept both kinds of memory.
(Edit, re below reply: It depends how you define "allocation"; it's either two or three. I wasn't considering the stack as allocation, but you're right that Rust takes the traditional stack/heap distinction and expands it to stack/exchange heap/task heap. We should update the tutorial to make it clear that borrowed pointers work for the stack as well as both heaps.)
I agree that the language is not designed to be a Python replacement, however. No language is suitable for every task.
Rust has three "realms" in which objects can be allocated: the stack, the local heap, and the exchange heap. These realms have corresponding pointer types: the borrowed pointer (&T), the shared box (@T), and the unique box (~T). These three sigils will appear repeatedly as we explore the language. Learning the appropriate role of each is key to using Rust effectively."
Rust statically prevents leaks and double-frees, warns about implicit copies of large structures, and has GC built in if I want to use it. It's certainly more familiar to a Python dev than C++. The whole trait system is even like a built-in and vastly simpler zope.interface.
A Python replacement, this ain't. More like C++ on quaaludes.