error[E0509]: cannot move out of type `A`, which implements the `Drop` trait
  --> $DIR/functional-struct-update-noncopyable.rs:12:14
   |
LL |     let _b = A { y: Arc::new(3), ..a };
   |              ^^^^^^^^^^^^^^^^^^^^^^^^^
   |              |
   |              cannot move out of here
   |              move occurs because `a.x` has type `Arc<isize>`, which does not implement the `Copy` trait
   |
help: clone the value from the field instead of using the functional record update syntax
   |
LL -     let _b = A { y: Arc::new(3), ..a };
LL +     let _b = A { y: Arc::new(3), x: a.x.clone() };
   |

error: aborting due to 1 previous error

For more information about this error, try `rustc --explain E0509`.