// ./src/scope/borrow/alias.md struct Point { x: i32, y: i32, z: i32 } fn part0() { let mut point = Point { x: 0, y: 0, z: 0 }; let borrowed_point = &point; let another_borrow = &point; // Data can be accessed via the references and the original owner println!("Point has coordinates: ({}, {}, {})", borrowed_point.x, another_borrow.y, point.z); // Error! Can't borrow `point` as mutable because it's currently // borrowed as immutable. // let mutable_borrow = &mut point; // TODO ^ Try uncommenting this line // The borrowed values are used again here println!("Point has coordinates: ({}, {}, {})", borrowed_point.x, another_borrow.y, point.z); // The immutable references are no longer used for the rest of the code so // it is possible to reborrow with a mutable reference. let mutable_borrow = &mut point; // Change data via mutable reference mutable_borrow.x = 5; mutable_borrow.y = 2; mutable_borrow.z = 1; // Error! Can't borrow `point` as immutable because it's currently // borrowed as mutable. // let y = &point.y; // TODO ^ Try uncommenting this line // Error! Can't print because `println!` takes an immutable reference. // println!("Point Z coordinate is {}", point.z); // TODO ^ Try uncommenting this line // Ok! Mutable references can be passed as immutable to `println!` println!("Point has coordinates: ({}, {}, {})", mutable_borrow.x, mutable_borrow.y, mutable_borrow.z); // The mutable reference is no longer used for the rest of the code so it // is possible to reborrow let new_borrowed_point = &point; println!("Point now has coordinates: ({}, {}, {})", new_borrowed_point.x, new_borrowed_point.y, new_borrowed_point.z); } pub fn main() { part0(); }