#![feature(plugin)] #![plugin(clippy)] #![deny(clippy)] pub fn test(foo: Box>) { //~ ERROR You seem to be trying to use Box> println!("{:?}", foo.get(0)) } pub fn test2(foo: Box)>) { // pass if #31 is fixed foo(vec![1, 2, 3]) } fn main(){ test(Box::new(Vec::new())); test2(Box::new(|v| println!("{:?}", v))); }