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// Regression test for #20831: debruijn index account was thrown off
// by the (anonymous) lifetime in `<Self as Publisher>::Output`
// below. Note that changing to a named lifetime made the problem go
// away.
use std::cell::RefCell;
use std::ops::{Shl, Shr};
pub trait Subscriber {
type Input;
}
pub trait Publisher<'a> {
type Output;
fn subscribe(&mut self, _: Box<dyn Subscriber<Input=Self::Output> + 'a>);
}
pub trait Processor<'a> : Subscriber + Publisher<'a> { }
impl<'a, P> Processor<'a> for P where P : Subscriber + Publisher<'a> { }
struct MyStruct<'a> {
sub: Box<dyn Subscriber<Input=u64> + 'a>
}
impl<'a> Publisher<'a> for MyStruct<'a> {
type Output = u64;
fn subscribe(&mut self, t : Box<dyn Subscriber<Input=<Self as Publisher>::Output> + 'a>) {
// Not obvious, but there is an implicit lifetime here -------^
//~^^ ERROR cannot infer
//
// The fact that `Publisher` is using an implicit lifetime is
// what was causing the debruijn accounting to be off, so
// leave it that way!
self.sub = t;
}
}
fn main() {}
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