1 // revisions: edition2015 edition2021 2 //[edition2021]edition:2021 3 4 #![allow(warnings)] 5 ice() -> impl AsRef<Fn(&())>6fn ice() -> impl AsRef<Fn(&())> { 7 //[edition2015]~^ ERROR: the trait bound `(): AsRef<(dyn for<'a> Fn(&'a ()) + 'static)>` is not satisfied [E0277] 8 //[edition2021]~^^ ERROR: trait objects must include the `dyn` keyword [E0782] 9 todo!() 10 } 11 main()12fn main() {} 13