ch11-03: Unnecessary import removal

[deep-outcome]

Qualified call to add_two is sufficient. There is no need to import adder with use adder;.

[deep-outcome]

Articles

If our project is a binary crate that only contains a src/main.rs file and doesn’t have a src/lib.rs file, we can’t create integration tests in the tests directory and bring functions defined in the src/main.rs file into scope with a use statement. Only library crates expose functions that other crates can use; binary crates are meant to be run on their own.

This is one of the reasons Rust projects that provide a binary have a straightforward src/main.rs file that calls logic that lives in the src/lib.rs file. Using that structure, integration tests can test the library crate with use to make the important functionality available. If the important functionality works, the small amount of code in the src/main.rs file will work as well, and that small amount of code doesn’t need to be tested.

debates using use. While use can be employed to import particular items, circumstances should be clearer. Mayhap listing 11-13 can be just changed to

use adder::add_two;

#[test]
fn it_adds_two() {
    assert_eq!(4, add_two(2));
}

That would demonstrate scoping is taking its turn. I am not really sure what information removed article is supposed to bring in. Thus I cannot alter it.

[chriskrycho]

Ah, this dates to back in the Rust 2015 Edition era, when you had to jump through a lot more hoops with the module system design! Thanks for the PR. I am going to make a couple tweaks to it before merging, but this will be a nice little improvement.