102140.rs

#![feature(return_position_impl_trait_in_trait)]

trait Marker {}
impl Marker for u32 {}

trait MyTrait {
    fn foo(&self) -> impl Marker
        where Self: Sized;
}

struct Outer;

impl MyTrait for Outer {
    fn foo(&self) -> impl Marker {
        42
    }
}

impl dyn MyTrait {
    fn other(&self) -> impl Marker {
        MyTrait::foo(&self)
    }
}