error[E0599]: no method named `foo` found for reference `&dyn Foo` in the current scope
  --> $DIR/issue-5153.rs:10:27
   |
LL |     fn foo(self: Box<Self>);
   |                  --------- the method might not be found because of this arbitrary self type
...
LL |     (&5isize as &dyn Foo).foo();
   |                           ^^^ method not found in `&dyn Foo`

error: aborting due to previous error

For more information about this error, try `rustc --explain E0599`.