2015-05-14 07:04:49 -05:00
|
|
|
// Check that you can cast between different pointers to trait objects
|
|
|
|
// whose vtable have the same kind (both lengths, or both trait pointers).
|
|
|
|
|
2017-12-23 15:38:09 -06:00
|
|
|
#![feature(unsized_tuple_coercion)]
|
|
|
|
|
2015-05-05 11:39:27 -05:00
|
|
|
trait Foo<T> {
|
|
|
|
fn foo(&self, _: T) -> u32 { 42 }
|
|
|
|
}
|
|
|
|
|
|
|
|
trait Bar {
|
|
|
|
fn bar(&self) { println!("Bar!"); }
|
|
|
|
}
|
|
|
|
|
|
|
|
impl<T> Foo<T> for () {}
|
|
|
|
impl Foo<u32> for u32 { fn foo(&self, _: u32) -> u32 { self+43 } }
|
|
|
|
impl Bar for () {}
|
|
|
|
|
2019-05-28 13:47:21 -05:00
|
|
|
unsafe fn round_trip_and_call<'a>(t: *const (dyn Foo<u32>+'a)) -> u32 {
|
|
|
|
let foo_e : *const dyn Foo<u16> = t as *const _;
|
|
|
|
let r_1 = foo_e as *mut dyn Foo<u32>;
|
2015-05-05 11:39:27 -05:00
|
|
|
|
2015-06-18 07:51:06 -05:00
|
|
|
(&*r_1).foo(0)
|
2015-05-05 11:39:27 -05:00
|
|
|
}
|
|
|
|
|
|
|
|
#[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>
|
|
|
|
}
|
|
|
|
|
2017-12-23 15:38:09 -06:00
|
|
|
fn tuple_i32_to_u32<T:?Sized>(u: *const (i32, T)) -> *const (u32, T) {
|
|
|
|
u as *const (u32, T)
|
|
|
|
}
|
|
|
|
|
|
|
|
|
2015-05-05 11:39:27 -05:00
|
|
|
fn main() {
|
|
|
|
let x = 4u32;
|
2019-05-28 13:47:21 -05:00
|
|
|
let y : &dyn Foo<u32> = &x;
|
|
|
|
let fl = unsafe { round_trip_and_call(y as *const dyn Foo<u32>) };
|
2015-06-18 07:51:06 -05:00
|
|
|
assert_eq!(fl, (43+4));
|
2015-05-05 11:39:27 -05:00
|
|
|
|
|
|
|
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]);
|
2017-12-23 15:38:09 -06:00
|
|
|
|
|
|
|
// this assumes that tuple reprs for (i32, _) and (u32, _) are
|
|
|
|
// the same.
|
|
|
|
let s = (0i32, [0, 1, 2]);
|
|
|
|
let u: &(i32, [u8]) = &s;
|
|
|
|
let u: *const (i32, [u8]) = u;
|
|
|
|
let u_u32 : *const (u32, [u8]) = tuple_i32_to_u32(u);
|
|
|
|
unsafe {
|
|
|
|
assert_eq!(&(*u_u32).1, &[0, 1, 2]);
|
|
|
|
}
|
2015-05-05 11:39:27 -05:00
|
|
|
}
|