error[E0599]: no method named `foo` found for type `&dyn Foo` in the current scope --> $DIR/issue-5153.rs:20:23 | LL | (&5isize as &Foo).foo(); | ^^^ | = help: items from traits can only be used if the trait is implemented and in scope = note: the following trait defines an item `foo`, perhaps you need to implement it: candidate #1: `Foo` error: aborting due to previous error For more information about this error, try `rustc --explain E0599`.