| //@ run-pass |
| // Check that you can cast between different pointers to trait objects |
| // whose vtable have the same kind (both lengths, or both trait pointers). |
| |
| trait Bar { //~ WARN trait `Bar` is never used |
| fn bar(&self) { println!("Bar!"); } |
| } |
| |
| impl Bar for () {} |
| |
| #[repr(C)] |
| struct FooS<T:?Sized>(T); |
| #[repr(C)] |
| struct BarS<T:?Sized>(T); |
| |
| fn foo_to_bar<T:?Sized>(u: *const FooS<T>) -> *const BarS<T> { |
| u as *const BarS<T> |
| } |
| |
| |
| fn main() { |
| let s = FooS([0,1,2]); |
| let u: &FooS<[u32]> = &s; |
| let u: *const FooS<[u32]> = u; |
| let bar_ref : *const BarS<[u32]> = foo_to_bar(u); |
| let z : &BarS<[u32]> = unsafe{&*bar_ref}; |
| assert_eq!(&z.0, &[0,1,2]); |
| } |
