rust/tests/run-pass/tag-align-dyn-u64.rs
2020-04-16 09:25:12 +02:00

37 lines
902 B
Rust

// Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
use std::mem;
enum Tag<A> {
Tag2(A)
}
#[allow(dead_code)]
struct Rec {
c8: u8,
t: Tag<u64>
}
fn mk_rec() -> Rec {
return Rec { c8:0, t:Tag::Tag2(0) };
}
fn is_u64_aligned(u: &Tag<u64>) -> bool {
let p: usize = unsafe { mem::transmute(u) };
let u64_align = std::mem::align_of::<u64>();
return (p & (u64_align - 1)) == 0;
}
pub fn main() {
let x = mk_rec();
assert!(is_u64_aligned(&x.t));
}