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