rust/src/test/ui/fat-ptr-cast-rpass.rs
2019-07-27 18:56:17 +03:00

42 lines
832 B
Rust

// run-pass
#![feature(raw)]
use std::mem;
use std::raw;
trait Foo {
fn foo(&self) {}
}
struct Bar;
impl Foo for Bar {}
fn main() {
// Test we can turn a fat pointer to array back into a thin pointer.
let a: *const [i32] = &[1, 2, 3];
let b = a as *const [i32; 2];
unsafe {
assert_eq!(*b, [1, 2]);
}
// Test conversion to an address (usize).
let a: *const [i32; 3] = &[1, 2, 3];
let b: *const [i32] = a;
assert_eq!(a as usize, b as *const () as usize);
// And conversion to a void pointer/address for trait objects too.
let a: *mut dyn Foo = &mut Bar;
let b = a as *mut ();
let c = a as *const () as usize;
let d = unsafe {
let r: raw::TraitObject = mem::transmute(a);
r.data
};
assert_eq!(b, d);
assert_eq!(c, d as usize);
}