What sort order does Rust's built-in cmp for &str use?

As I understood from this question, there are many ways to interpret the order of two strings.

Rust provides a default implementation for Ord for str, but I can't find the answer to these questions:

• Does it sort character by character, or by raw byte value?
• If it sorts by characters, which locale does it use?

Just read the source!

The documentation generated by RustDoc -- which is used for the officially hosted documentation, among others -- always include a link to the source:

impl Ord for str {
    #[inline]
    fn cmp(&self, other: &str) -> Ordering {
        self.as_bytes().cmp(other.as_bytes())
    }
}

The answer, thus, is that for equality & ordering, Rust considers a str as just a slice of bytes.