| #![crate_type = "lib"] | |
| pub trait Future { | |
| type Item; | |
| type Error; | |
| } | |
| impl Future for u32 { | |
| type Item = (); | |
| type Error = Box<()>; | |
| } | |
| fn foo() -> Box<Future<Item=(), Error=Box<()>>> { | |
| Box::new(0u32) | |
| } | |
| pub fn bar<F, A, B>(_s: F) | |
| where F: Fn(A) -> B, | |
| { | |
| foo(); | |
| } |