// Copyright 2015 The Rust Project Developers. See the COPYRIGHT // file at the top-level directory of this distribution and at // http://rust-lang.org/COPYRIGHT. // // Licensed under the Apache License, Version 2.0 or the MIT license // , at your // option. This file may not be copied, modified, or distributed // except according to those terms. pub trait Subscriber { type Input; } pub trait Processor: Subscriber { //~^ ERROR unsupported cyclic reference between types/traits detected [E0391] type Input; } fn main() {}