error[E0277]: the trait bound `f32: Foo` is not satisfied
  --> $DIR/impl_wf_2.rs:25:17
   |
LL |     type Item = f32;
   |                 ^^^ the trait `Foo` is not implemented for `f32`
   |
   = help: the trait `Foo` is implemented for `i32`
note: required by a bound in `Bar::Item`
  --> $DIR/impl_wf_2.rs:8:16
   |
LL |     type Item: Foo;
   |                ^^^ required by this bound in `Bar::Item`

error: aborting due to previous error

For more information about this error, try `rustc --explain E0277`.