--- /dev/null
+// Copyright 2016 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 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#![feature(specialization)]
+
+fn main() {}
+
+pub trait Alpha<T> { }
+
+pub trait Beta {
+ type Event;
+}
+
+pub trait Delta {
+ type Handle;
+ fn process(&self);
+}
+
+pub struct Parent<A, T>(A, T);
+
+impl<A, T> Delta for Parent<A, T>
+where A: Alpha<T::Handle>,
+ T: Delta,
+ T::Handle: Beta<Event = <Handle as Beta>::Event> {
+ type Handle = Handle;
+ default fn process(&self) {
+ unimplemented!()
+ }
+}
+
+impl<A, T> Delta for Parent<A, T>
+where A: Alpha<T::Handle> + Alpha<Handle>,
+ T: Delta,
+ T::Handle: Beta<Event = <Handle as Beta>::Event> {
+ fn process(&self) {
+ unimplemented!()
+ }
+}
+
+pub struct Handle;
+
+impl Beta for Handle {
+ type Event = ();
+}
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