| //@ run-pass | |
| #![allow(non_camel_case_types)] | |
| trait double { | |
| fn double(self: Box<Self>) -> usize; | |
| } | |
| impl double for usize { | |
| fn double(self: Box<usize>) -> usize { *self * 2 } | |
| } | |
| pub fn main() { | |
| let x: Box<_> = Box::new(Box::new(3usize) as Box<dyn double>); | |
| assert_eq!(x.double(), 6); | |
| } |