use std::any::Any; fn main() { fn h(x:i32) -> i32 {3*x} let mut vfnfer:Vec> = vec![]; vfnfer.push(Box::new(h)); println!("{:?}",(vfnfer[0] as dyn Fn)(3)); //~^ ERROR the precise format of `Fn`-family traits' //~| ERROR missing generics for trait `Fn` //~| ERROR the value of the associated type `Output` in `FnOnce` }