error[E0223]: ambiguous associated type
  --> $DIR/suggest-trait-in-ufcs-in-hrtb.rs:5:38
   |
LL | impl<S> Foo for Bar<S> where for<'a> <&'a S>::Item: Foo {}
   |                                      ^^^^^^^^^^^^^ help: use fully-qualified syntax: `<&'a S as IntoIterator>::Item`

error: aborting due to 1 previous error

For more information about this error, try `rustc --explain E0223`.