16 let mut u = U { s: S { a: 0, b: 1 } };
22 let mut u = U { s: S { a: 0, b: 1 } };
24 let b = u.c; //~ ERROR cannot use `u.c` because it was mutably borrowed
30 trait Fake { fn use_mut(&mut self) { } fn use_ref(&self) { } }
31 impl<T> Fake for T { }