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