| // compile-flags: -Ztrait-solver=next | |
| // check-pass | |
| #![feature(trait_upcasting)] | |
| trait A {} | |
| trait B: A {} | |
| impl A for usize {} | |
| impl B for usize {} | |
| trait Mirror { | |
| type Assoc: ?Sized; | |
| } | |
| impl<T: ?Sized> Mirror for T { | |
| type Assoc = T; | |
| } | |
| fn main() { | |
| let x = Box::new(1usize) as Box<<dyn B as Mirror>::Assoc>; | |
| let y = x as Box<<dyn A as Mirror>::Assoc>; | |
| } |