Comment by steveklabnik

In a language that's as strongly typed as Rust, any change can be breaking. So for example, let's say that you had code that looks like this:

    use std::cell::*;

    struct MoveCell;

We then add a new type to std::cell, also named MoveCell. Your code will now fail to compile, as the two structures conflict.

This kind of breakage can still happen, even though we care a lot about stability.