Example: ``` rust #![crate_type="lib"] pub use a::Child; mod a { pub trait Parent {} pub trait Child: Parent {} } ``` Looks like this wasn't covered by #17401, but this seems wrong as part of [RFC 48](https://github.com/rust-lang/rfcs/blob/master/complete/0048-no-privates-in-public.md#non-public-items-referenced-by-a-pub-use).