1 error[E0599]: no method named `f` found for type `()` in the current scope
2 --> $DIR/shadowed-trait-methods.rs:13:8
7 = help: items from traits can only be used if the trait is in scope
8 help: the following trait is implemented but not in scope, perhaps add a `use` for it:
13 error: aborting due to previous error
15 For more information about this error, try `rustc --explain E0599`.