note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
--> $DIR/wf-object-safe.rs:5:23
|
LL | trait A {
| - this trait cannot be made into an object...
LL | fn foo(&self, _x: &Self);
| ^^^^^ ...because method `foo` references the `Self` type in this parameter