rust/tests/ui/cast/fat-ptr-cast-rpass.rs
2024-02-16 20:02:50 +00:00

35 lines
793 B
Rust

//@ run-pass
#![feature(ptr_metadata)]
trait Foo {
fn foo(&self) {} //~ WARN method `foo` is never used
}
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 () as usize;
let c = a as *const () as usize;
let d = a.to_raw_parts().0 as usize;
assert_eq!(b, d);
assert_eq!(c, d);
}