Traits associated items are rejected in super-trait bounds

[huonw]

#![feature(associated_types)]

trait Wub {
    type Zoop;
}

trait Flim: Wub {}

fn main() {}

<anon>:7:13: 7:16 error: associated types may not be referenced here
<anon>:7 trait Flim: Wub {}
                     ^~~

[huonw]

@aturon and I suspect there may be some overlap with/duplication of #18768 but we're not familiar enough with the jargon/implementation details to be sure.

[aldanor]

This now compiles on nightly, should probably be closed.

[alexcrichton]

Thanks @aldanor!