1 error[E0599]: no method named `f` found for fn pointer `fn(&u8)` in the current scope
2 --> $DIR/issue-57362-1.rs:20:7
5 | ^ method not found in `fn(&u8)`
7 = help: items from traits can only be used if the trait is implemented and in scope
8 note: `Trait` defines an item `f`, perhaps you need to implement it
9 --> $DIR/issue-57362-1.rs:8:1
14 error: aborting due to 1 previous error
16 For more information about this error, try `rustc --explain E0599`.