4 fn get_inner_ref(&self) -> &Vec<usize> {
10 let client = TestClient;
11 let inner = client.get_inner_ref();
12 //~^ NOTE consider changing this binding's type to be
14 //~^ ERROR cannot borrow `*inner` as mutable, as it is behind a `&` reference [E0596]
15 //~| NOTE `inner` is a `&` reference, so the data it refers to cannot be borrowed as mutable