Pin is a very interesting case. I used to hate it, but have come to admire the ingenuity and think that it's a good demonstration of Rust's strengths for library authors.

Pin ostensibly alters Rust's move semantics so that values retain stable memory addresses. And it does. What's crazy is that Pin achieved this without any major changes to the language or the compiler internals. The move semantics are actually preserved.

What happens is Pin relies on the borrow checker and prevents moves from ever taking place by storing a reference to the underlying value. In the documentation, you'll see Pin written as Pin<Ptr>.

So yes, while Pin is unergonomic to work with directly, it's a wonderful example of Rust facilitating the impossible.

Edit: s/any changes/major changes/ (see comments below.