error[E0046]: not all trait items implemented, missing: `Target`, `deref`
  --> $DIR/dont-suggest-import-on-deref-err.rs:7:1
   |
LL | impl Deref for Foo {}
   | ^^^^^^^^^^^^^^^^^^ missing `Target`, `deref` in implementation
   |
   = help: implement the missing item: `type Target = /* Type */;`
   = help: implement the missing item: `fn deref(&self) -> &<Self as Deref>::Target { todo!() }`

error: aborting due to 1 previous error

For more information about this error, try `rustc --explain E0046`.