error[E0446]: private type `Foo::Bar` in public interface
  --> $DIR/E0446.rs:14:5
   |
LL | /     pub fn bar() -> Bar { //~ ERROR E0446
LL | |         Bar(0)
LL | |     }
   | |_____^ can't leak private type

error: aborting due to previous error

For more information about this error, try `rustc --explain E0446`.