1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
|
// run-pass
#![allow(dead_code)]
// Test that pointers and references to extern types are thin, ie they have the same size and
// alignment as a pointer to ().
#![feature(extern_types)]
use std::mem::{align_of, size_of};
extern "C" {
type A;
}
struct Foo {
x: u8,
tail: A,
}
struct Bar<T: ?Sized> {
x: u8,
tail: T,
}
fn assert_thin<T: ?Sized>() {
assert_eq!(size_of::<*const T>(), size_of::<*const ()>());
assert_eq!(align_of::<*const T>(), align_of::<*const ()>());
assert_eq!(size_of::<*mut T>(), size_of::<*mut ()>());
assert_eq!(align_of::<*mut T>(), align_of::<*mut ()>());
assert_eq!(size_of::<&T>(), size_of::<&()>());
assert_eq!(align_of::<&T>(), align_of::<&()>());
assert_eq!(size_of::<&mut T>(), size_of::<&mut ()>());
assert_eq!(align_of::<&mut T>(), align_of::<&mut ()>());
}
fn main() {
assert_thin::<A>();
assert_thin::<Foo>();
assert_thin::<Bar<A>>();
assert_thin::<Bar<Bar<A>>>();
}
|