error[E0038]: the trait `Foo` is not dyn compatible
  --> $DIR/dispatch-dyn-incompatible-that-does-not-deref.rs:12:13
   |
LL |     fn method(self: &W) {}
   |                     -- help: consider changing method `method`'s `self` parameter to be `&self`: `&Self`
...
LL | fn test(x: &dyn Foo) {
   |             ^^^^^^^ `Foo` is not dyn compatible
   |
note: for a trait to be dyn compatible it needs to allow building a vtable
      for more information, visit <https://doc.rust-lang.org/reference/items/traits.html#dyn-compatibility>
  --> $DIR/dispatch-dyn-incompatible-that-does-not-deref.rs:8:21
   |
LL | trait Foo: Deref<Target = W> {
   |       --- this trait is not dyn compatible...
LL |     fn method(self: &W) {}
   |                     ^^ ...because method `method`'s `self` parameter cannot be dispatched on

error[E0307]: invalid `self` parameter type: `&W`
  --> $DIR/dispatch-dyn-incompatible-that-does-not-deref.rs:8:21
   |
LL |     fn method(self: &W) {}
   |                     ^^
   |
   = note: type of `self` must be `Self` or a type that dereferences to it
   = help: consider changing to `self`, `&self`, `&mut self`, `self: Box<Self>`, `self: Rc<Self>`, `self: Arc<Self>`, or `self: Pin<P>` (where P is one of the previous types except `Self`)

error[E0038]: the trait `Foo` is not dyn compatible
  --> $DIR/dispatch-dyn-incompatible-that-does-not-deref.rs:14:5
   |
LL |     fn method(self: &W) {}
   |                     -- help: consider changing method `method`'s `self` parameter to be `&self`: `&Self`
...
LL |     x.method();
   |     ^^^^^^^^^^ `Foo` is not dyn compatible
   |
note: for a trait to be dyn compatible it needs to allow building a vtable
      for more information, visit <https://doc.rust-lang.org/reference/items/traits.html#dyn-compatibility>
  --> $DIR/dispatch-dyn-incompatible-that-does-not-deref.rs:8:21
   |
LL | trait Foo: Deref<Target = W> {
   |       --- this trait is not dyn compatible...
LL |     fn method(self: &W) {}
   |                     ^^ ...because method `method`'s `self` parameter cannot be dispatched on

error: aborting due to 3 previous errors

Some errors have detailed explanations: E0038, E0307.
For more information about an error, try `rustc --explain E0038`.