Use and pub

  1. 🌟 We can bring two types of the same name into the same scope with use, but you need as keyword.
use std::fmt::Result;
use std::io::Result;

fn main() {}
  1. 🌟🌟 If we are using multiple items defined in the same crate or module, then listing each item on its own line will take up too much vertical space.

// FILL in the blank in two ways
// DON'T add new code line
use std::collections::__;

fn main() {
    let _c1:HashMap<&str, i32> = HashMap::new();
    let mut c2 = BTreeMap::new();
    c2.insert(1, "a");
    let _c3: HashSet<i32> = HashSet::new();

Re-exporting names with pub use

  1. 🌟🌟🌟 In our recently created package hello-package, add something to make the below code work
fn main() {
    assert_eq!(hello_package::hosting::seat_at_table(), "sit down please");
     assert_eq!(hello_package::eat_at_restaurant(),"yummy yummy!");

Pub(in Crate)

Sometimes we want an item only be public to a certain crate. For this we can use the pub(in Crate) syntax.


pub mod a {
    pub const I: i32 = 3;

    fn semisecret(x: i32) -> i32 {
        use self::b::c::J;
        x + J

    pub fn bar(z: i32) -> i32 {
        semisecret(I) * z
    pub fn foo(y: i32) -> i32 {
        semisecret(I) + y

    mod b {
        pub(in crate::a) mod c {
            pub(in crate::a) const J: i32 = 4;

Full Code

The full code of hello-package is here.

You can find the solutions here (under the solutions path), but only use it when you need it :)