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#![feature(unsize, dispatch_from_dyn)]
use std::{
ops::DispatchFromDyn,
marker::{Unsize, PhantomData},
};
struct WrapperWithExtraField<T>(T, i32);
impl<T, U> DispatchFromDyn<WrapperWithExtraField<U>> for WrapperWithExtraField<T>
//~^ ERROR [E0378]
where
T: DispatchFromDyn<U>,
{}
struct MultiplePointers<T: ?Sized>{
ptr1: *const T,
ptr2: *const T,
}
impl<T: ?Sized, U: ?Sized> DispatchFromDyn<MultiplePointers<U>> for MultiplePointers<T>
//~^ implementing `DispatchFromDyn` does not allow multiple fields to be coerced
where
T: Unsize<U>,
{}
struct NothingToCoerce<T: ?Sized> {
data: PhantomData<T>,
}
impl<T: ?Sized, U: ?Sized> DispatchFromDyn<NothingToCoerce<T>> for NothingToCoerce<U> {}
//~^ ERROR implementing `DispatchFromDyn` requires a field to be coerced
#[repr(C)]
struct HasReprC<T: ?Sized>(Box<T>);
impl<T: ?Sized, U: ?Sized> DispatchFromDyn<HasReprC<U>> for HasReprC<T>
//~^ ERROR [E0378]
where
T: Unsize<U>,
{}
#[repr(align(64))]
struct OverAlignedZst;
struct OverAligned<T: ?Sized>(Box<T>, OverAlignedZst);
impl<T: ?Sized, U: ?Sized> DispatchFromDyn<OverAligned<U>> for OverAligned<T>
//~^ ERROR [E0378]
where
T: Unsize<U>,
{}
fn main() {}
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