I don't think this is an operator overloading thing? It's just that `x = y + x` is equivalent to z = y + x x = z Basically, creating an object `z` jus

I don't think this is an operator overloading thing? It's just that `x = y + x` is equivalent to z = y + x x = z Basically, creating an object `z` just to throw it away. `x += y` just adds y to x directly without any intermediary. You could write this in any language pretty easily. For example, in Rust: let x = "abc".to_string(); let y = "123".to_string(); let x = x + &y; as opposed to the more efficient: let mut x = "abc".to_string(); let y = "123".to_string(); x.push_str(&y); It's just using an operation to mutate in place vs an immutable operation.