error[E0507]: cannot move out of index of `Vec<String>`
  --> $DIR/issue-40402-1.rs:9:13
   |
LL |     let e = f.v[0];
   |             ^^^^^^
   |             |
   |             move occurs because value has type `String`, which does not implement the `Copy` trait
   |             help: consider borrowing here: `&f.v[0]`

error: aborting due to previous error

For more information about this error, try `rustc --explain E0507`.