#![feature(box_syntax)] use std::any::Any; fn main() { fn h(x:i32) -> i32 {3*x} let mut vfnfer:Vec> = vec![]; vfnfer.push(box h); println!("{:?}",(vfnfer[0] as Fn)(3)); //~^ ERROR the precise format of `Fn`-family traits' //~| ERROR wrong number of type arguments: expected 1, found 0 [E0107] //~| ERROR the value of the associated type `Output` (from the trait `std::ops::FnOnce`) }