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// run-pass
//! Test that #[derive(Copy, Clone)] produces a shallow copy
//! even when a member violates RFC 1521
use std::sync::atomic::{AtomicBool, Ordering};
/// A struct that pretends to be Copy, but actually does something
/// in its Clone impl
#[derive(Copy)]
struct Liar;
/// Static cooperating with the rogue Clone impl
static CLONED: AtomicBool = AtomicBool::new(false);
impl Clone for Liar {
fn clone(&self) -> Self {
// this makes Clone vs Copy observable
CLONED.store(true, Ordering::SeqCst);
*self
}
}
/// This struct is actually Copy... at least, it thinks it is!
#[derive(Copy, Clone)]
struct Innocent(#[allow(unused_tuple_struct_fields)] Liar);
impl Innocent {
fn new() -> Self {
Innocent(Liar)
}
}
fn main() {
let _ = Innocent::new().clone();
// if Innocent was byte-for-byte copied, CLONED will still be false
assert!(!CLONED.load(Ordering::SeqCst));
}
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