1 files changed, 38 insertions, 0 deletions
diff --git a/tests/ui/deriving/deriving-copyclone.rs b/tests/ui/deriving/deriving-copyclone.rs
new file mode 100644
index 000000000..f8403b1fe
--- /dev/null
+++ b/tests/ui/deriving/deriving-copyclone.rs
@@ -0,0 +1,38 @@
+// 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));
+}