error[E0782]: trait objects must include the `dyn` keyword
  --> $DIR/generic-with-implicit-hrtb-without-dyn.rs:6:24
   |
LL | fn ice() -> impl AsRef<Fn(&())> {
   |                        ^^^^^^^
   |
help: add `dyn` keyword before this trait
   |
LL | fn ice() -> impl AsRef<dyn Fn(&())> {
   |                        +++

error: aborting due to previous error

For more information about this error, try `rustc --explain E0782`.