mirror of https://github.com/rust-lang/rust
16 lines
303 B
Rust
16 lines
303 B
Rust
//@ 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);
|
|
}
|