27 lines
483 B
Rust
27 lines
483 B
Rust
|
//@ known-bug: rust-lang/rust#129219
|
||
|
|
//@ compile-flags: -Zmir-opt-level=5 -Zvalidate-mir --edition=2018
|
||
|
|
|
||
|
|
use core::marker::Unsize;
|
||
|
|
|
||
|
|
pub trait CastTo<T: ?Sized>: Unsize<T> {}
|
||
|
|
|
||
|
|
impl<T: ?Sized, U: ?Sized> CastTo<T> for U {}
|
||
|
|
|
||
|
|
impl<T: ?Sized> Cast for T {}
|
||
|
|
pub trait Cast {
|
||
|
|
fn cast<T: ?Sized>(&self) -> &T
|
||
|
|
where
|
||
|
|
Self: CastTo<T>,
|
||
|
|
{
|
||
|
|
self
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
pub trait Foo {}
|
||
|
|
impl Foo for [i32; 0] {}
|
||
|
|
|
||
|
|
fn main() {
|
||
|
|
let x: &dyn Foo = &[];
|
||
|
|
let x = x.cast::<[i32]>();
|
||
|
|
}
|