error[E0277]: the trait bound `(): Trait<for<'b> fn(fn(&'b u32))>` is not satisfied
  --> $DIR/hrtb-exists-forall-trait-covariant.rs:36:5
   |
LL |     foo::<()>();
   |     ^^^^^^^^^ the trait `Trait<for<'b> fn(fn(&'b u32))>` is not implemented for `()`
   |
   = help: the following implementations were found:
             <() as Trait<fn(fn(&'a u32))>>
note: required by `foo`
  --> $DIR/hrtb-exists-forall-trait-covariant.rs:8:1
   |
LL | / fn foo<T>()
LL | | where
LL | |     T: Trait<for<'b> fn(fn(&'b u32))>,
LL | | {
LL | | }
   | |_^

error: aborting due to previous error

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