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// run-pass
// Test a very simple custom DST coercion.
#![feature(unsize, coerce_unsized)]
use std::ops::CoerceUnsized;
use std::marker::Unsize;
struct Bar<T: ?Sized> {
x: *const T,
}
impl<T: ?Sized+Unsize<U>, U: ?Sized> CoerceUnsized<Bar<U>> for Bar<T> {}
trait Baz {
fn get(&self) -> i32;
}
impl Baz for i32 {
fn get(&self) -> i32 {
*self
}
}
fn main() {
// Arrays.
let a: Bar<[i32; 3]> = Bar { x: &[1, 2, 3] };
// This is the actual coercion.
let b: Bar<[i32]> = a;
unsafe {
assert_eq!((*b.x)[0], 1);
assert_eq!((*b.x)[1], 2);
assert_eq!((*b.x)[2], 3);
}
// Trait objects.
let a: Bar<i32> = Bar { x: &42 };
let b: Bar<dyn Baz> = a;
unsafe {
assert_eq!((*b.x).get(), 42);
}
}
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