Rust: What is the difference between &mut self and &self in Rust?

&mut self — mutable borrow. &self — immutable borrow.

&self (immutable):

• Cannot modify self.
• Multiple allowed.
• Read-only access.

1impl Person {
2    fn name(&self) -> &str {
3        &self.name
4    }
5}

**&mut self (mutable):

• Can modify self.
• Only one at a time.
• Read-write access.

1impl Person {
2    fn set_name(&mut self, name: String) {
3        self.name = name;
4    }
5}

Key differences:

• &self — immutable, multiple.
• &mut self — mutable, exclusive.