1error[E0038]: the trait `Foo` cannot be made into an object
2  --> $DIR/arbitrary-self-types-not-object-safe.rs:33:32
3   |
4LL |     fn foo(self: &Rc<Self>) -> usize;
5   |                  --------- help: consider changing method `foo`'s `self` parameter to be `&self`: `&Self`
6...
7LL |     let x = Rc::new(5usize) as Rc<dyn Foo>;
8   |                                ^^^^^^^^^^^ `Foo` cannot be made into an object
9   |
10note: 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>
11  --> $DIR/arbitrary-self-types-not-object-safe.rs:8:18
12   |
13LL | trait Foo {
14   |       --- this trait cannot be made into an object...
15LL |     fn foo(self: &Rc<Self>) -> usize;
16   |                  ^^^^^^^^^ ...because method `foo`'s `self` parameter cannot be dispatched on
17
18error[E0038]: the trait `Foo` cannot be made into an object
19  --> $DIR/arbitrary-self-types-not-object-safe.rs:33:13
20   |
21LL |     fn foo(self: &Rc<Self>) -> usize;
22   |                  --------- help: consider changing method `foo`'s `self` parameter to be `&self`: `&Self`
23...
24LL |     let x = Rc::new(5usize) as Rc<dyn Foo>;
25   |             ^^^^^^^^^^^^^^^ `Foo` cannot be made into an object
26   |
27note: 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>
28  --> $DIR/arbitrary-self-types-not-object-safe.rs:8:18
29   |
30LL | trait Foo {
31   |       --- this trait cannot be made into an object...
32LL |     fn foo(self: &Rc<Self>) -> usize;
33   |                  ^^^^^^^^^ ...because method `foo`'s `self` parameter cannot be dispatched on
34   = note: required because of the requirements on the impl of `CoerceUnsized<Rc<dyn Foo>>` for `Rc<usize>`
35   = note: required by cast to type `Rc<dyn Foo>`
36
37error: aborting due to 2 previous errors
38
39For more information about this error, try `rustc --explain E0038`.
40