src/test/ui/error-codes/E0445.rs

trait Foo {
    fn dummy(&self) { }
}

pub trait Bar : Foo {}
//~^ ERROR private trait `Foo` in public interface [E0445]
pub struct Bar2<T: Foo>(pub T);
//~^ ERROR private trait `Foo` in public interface [E0445]
pub fn foo<T: Foo> (t: T) {}
//~^ ERROR private trait `Foo` in public interface [E0445]

fn main() {}