1 files changed, 26 insertions, 0 deletions
diff --git a/src/test/ui/traits/negative-impls/pin-unsound-issue-66544-clone.rs b/src/test/ui/traits/negative-impls/pin-unsound-issue-66544-clone.rs
new file mode 100644
index 000000000..a5b856465
--- /dev/null
+++ b/src/test/ui/traits/negative-impls/pin-unsound-issue-66544-clone.rs
@@ -0,0 +1,26 @@
+use std::cell::Cell;
+use std::marker::PhantomPinned;
+use std::pin::Pin;
+
+struct MyType<'a>(Cell<Option<&'a mut MyType<'a>>>, PhantomPinned);
+
+impl<'a> Clone for &'a mut MyType<'a> {
+    //~^ ERROR E0751
+    fn clone(&self) -> &'a mut MyType<'a> {
+        self.0.take().unwrap()
+    }
+}
+
+fn main() {
+    let mut unpinned = MyType(Cell::new(None), PhantomPinned);
+    let bad_addr = &unpinned as *const MyType<'_> as usize;
+    let mut p = Box::pin(MyType(Cell::new(Some(&mut unpinned)), PhantomPinned));
+
+    // p_mut1 is okay: it does not point to the bad_addr
+    let p_mut1: Pin<&mut MyType<'_>> = p.as_mut();
+    assert_ne!(bad_addr, &*p_mut1 as *const _ as usize);
+
+    // but p_mut2 does point to bad_addr! this is unsound
+    let p_mut2: Pin<&mut MyType<'_>> = p_mut1.clone();
+    assert_eq!(bad_addr, &*p_mut2 as *const _ as usize);
+}