1 error[E0378]: the trait `DispatchFromDyn` may only be implemented for structs containing the field being coerced, ZST fields with 1 byte alignment, and nothing else
2 --> $DIR/invalid_dispatch_from_dyn_impls.rs:10:1
4 LL | impl<T, U> DispatchFromDyn<WrapperWithExtraField<U>> for WrapperWithExtraField<T>
5 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
7 = note: extra field `1` of type `i32` is not allowed
9 error[E0378]: implementing the `DispatchFromDyn` trait requires multiple coercions
10 --> $DIR/invalid_dispatch_from_dyn_impls.rs:21:1
12 LL | impl<T: ?Sized, U: ?Sized> DispatchFromDyn<MultiplePointers<U>> for MultiplePointers<T>
13 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
15 = note: the trait `DispatchFromDyn` may only be implemented for a coercion between structures with a single field being coerced
16 = note: currently, 2 fields need coercions: `ptr1` (`*const T` to `*const U`), `ptr2` (`*const T` to `*const U`)
18 error[E0378]: the trait `DispatchFromDyn` may only be implemented for a coercion between structures with a single field being coerced, none found
19 --> $DIR/invalid_dispatch_from_dyn_impls.rs:31:1
21 LL | impl<T: ?Sized, U: ?Sized> DispatchFromDyn<NothingToCoerce<T>> for NothingToCoerce<U> {}
22 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
24 error[E0378]: structs implementing `DispatchFromDyn` may not have `#[repr(packed)]` or `#[repr(C)]`
25 --> $DIR/invalid_dispatch_from_dyn_impls.rs:37:1
27 LL | impl<T: ?Sized, U: ?Sized> DispatchFromDyn<HasReprC<U>> for HasReprC<T>
28 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
30 error[E0378]: the trait `DispatchFromDyn` may only be implemented for structs containing the field being coerced, ZST fields with 1 byte alignment, and nothing else
31 --> $DIR/invalid_dispatch_from_dyn_impls.rs:46:1
33 LL | impl<T: ?Sized, U: ?Sized> DispatchFromDyn<OverAligned<U>> for OverAligned<T>
34 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
36 = note: extra field `1` of type `OverAlignedZst` is not allowed
38 error: aborting due to 5 previous errors
40 For more information about this error, try `rustc --explain E0378`.