| #![feature(unsize, coerce_unsized)] |
| |
| // Verfies that non-PhantomData ZSTs still cause coercions to fail. |
| // They might have additional semantics that we don't want to bulldoze. |
| |
| use std::marker::{Unsize, PhantomData}; |
| use std::ops::CoerceUnsized; |
| |
| struct NotPhantomData<T: ?Sized>(PhantomData<T>); |
| |
| struct MyRc<T: ?Sized> { |
| _ptr: *const T, |
| _boo: NotPhantomData<T>, |
| } |
| |
| impl<T: ?Sized + Unsize<U>, U: ?Sized> CoerceUnsized<MyRc<U>> for MyRc<T>{ } //~ERROR |
| |
| fn main() { |
| let data = [1, 2, 3]; |
| let iter = data.iter(); |
| let x = MyRc { _ptr: &iter, _boo: NotPhantomData(PhantomData) }; |
| let _y: MyRc<dyn Iterator<Item=&u32>> = x; |
| } |
