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//@ check-pass
#![feature(derive_coerce_pointee)]
#![feature(arbitrary_self_types)]
use std::ops::Deref;
use std::marker::CoercePointee;
use std::sync::Arc;
trait MyTrait {}
#[derive(CoercePointee)]
#[repr(transparent)]
struct MyArc<T>
where
T: MyTrait + ?Sized,
{
inner: Arc<T>
}
impl<T: MyTrait + ?Sized> Deref for MyArc<T> {
type Target = T;
fn deref(&self) -> &T {
&self.inner
}
}
// Proving that `MyArc<Self>` is dyn-dispatchable requires proving `MyArc<T>` implements
// `DispatchFromDyn<MyArc<U>>`. The `DispatchFromDyn` impl that is generated from the
// `CoercePointee` implementation requires the pointee impls `MyTrait`, but previously we
// were only assuming the pointee impl'd `MyOtherTrait`. Elaboration comes to the rescue here.
trait MyOtherTrait: MyTrait {
fn foo(self: MyArc<Self>);
}
fn test(_: MyArc<dyn MyOtherTrait>) {}
fn main() {}
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