First Example in https://doc.rust-lang.org/reference/visibility-and-privacy.html https://play.rust-lang.org/?version=stable&mode=debug&edition=2018&gist=215908aa41200a4e9ce3841cff3dd978 ``` Compiling playground v0.0.1 (/playground) error[E0432]: unresolved import `crate_helper_module` --> src/lib.rs:22:9 | 22 | use crate_helper_module; | ^^^^^^^^^^^^^^^^^^^ no external crate `crate_helper_module` ``` This line should be changed to ``` use crate::crate_helper_module; ```