error[E0433]: failed to resolve: use of undeclared crate or module `rect` --> $DIR/issue-101749.rs:17:13 | LL | let _ = rect::area(); | ^^^^ use of undeclared crate or module `rect` | help: you may have meant to call an instance method | LL | let _ = rect.area(); | ~ error: aborting due to previous error For more information about this error, try `rustc --explain E0433`.