error[E0378]: the trait `DispatchFromDyn` may only be implemented for structs containing the field being coerced, `PhantomData` fields, and nothing else
  --> $DIR/invalid_dispatch_from_dyn_impls.rs:20:1
   |
LL | / impl<T, U> DispatchFromDyn<WrapperWithExtraField<U>> for WrapperWithExtraField<T>
LL | | where
LL | |     T: DispatchFromDyn<U>,
LL | | {} //~^^^ ERROR [E0378]
   | |__^
   |
   = note: extra field `1` of type `i32` is not allowed

error[E0378]: implementing the `DispatchFromDyn` trait requires multiple coercions
  --> $DIR/invalid_dispatch_from_dyn_impls.rs:31:1
   |
LL | / impl<T: ?Sized, U: ?Sized> DispatchFromDyn<MultiplePointers<U>> for MultiplePointers<T>
LL | | where
LL | |     T: Unsize<U>,
LL | | {} //~^^^ ERROR [E0378]
   | |__^
   |
   = note: the trait `DispatchFromDyn` may only be implemented for a coercion between structures with a single field being coerced
   = note: currently, 2 fields need coercions: `ptr1` (`*const T` to `*const U`), `ptr2` (`*const T` to `*const U`)

error[E0378]: the trait `DispatchFromDyn` may only be implemented for a coercion between structures with a single field being coerced, none found
  --> $DIR/invalid_dispatch_from_dyn_impls.rs:41:1
   |
LL | impl<T: ?Sized, U: ?Sized> DispatchFromDyn<NothingToCoerce<T>> for NothingToCoerce<U> {}
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error[E0378]: structs implementing `DispatchFromDyn` may not have `#[repr(packed)]` or `#[repr(C)]`
  --> $DIR/invalid_dispatch_from_dyn_impls.rs:47:1
   |
LL | / impl<T: ?Sized, U: ?Sized> DispatchFromDyn<HasReprC<U>> for HasReprC<T>
LL | | where
LL | |     T: Unsize<U>,
LL | | {} //~^^^ ERROR [E0378]
   | |__^

error: aborting due to 4 previous errors

For more information about this error, try `rustc --explain E0378`.