error[E0191]: the value of the associated type `A` in `Foo` must be specified --> $DIR/issue-19482.rs:10:16 | LL | type A; | ------ `A` defined here ... LL | fn bar(x: &dyn Foo) {} | ^^^ help: specify the associated type: `Foo` error: aborting due to 1 previous error For more information about this error, try `rustc --explain E0191`.