error[E0382]: use of moved value: `foo`
  --> $DIR/as-ref-2.rs:10:14
   |
LL |     let foo = Some(Struct);
   |         --- move occurs because `foo` has type `Option<Struct>`, which does not implement the `Copy` trait
LL |     let _x: Option<Struct> = foo.map(|s| bar(&s));
   |                              --- ---------------- `foo` moved due to this method call
   |                              |
   |                              help: consider calling `.as_ref()` or `.as_mut()` to borrow the type's contents
LL |     let _y = foo;
   |              ^^^ value used here after move
   |
note: `Option::<T>::map` takes ownership of the receiver `self`, which moves `foo`
  --> $SRC_DIR/core/src/option.rs:LL:COL

error: aborting due to previous error

For more information about this error, try `rustc --explain E0382`.