= note: see issue #44874 <https://github.com/rust-lang/rust/issues/44874> for more information
= help: add `#![feature(arbitrary_self_types)]` to the crate attributes to enable
= 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`)