1 files changed, 96 insertions, 0 deletions
diff --git a/tests/ui/union/union-borrow-move-parent-sibling.rs b/tests/ui/union/union-borrow-move-parent-sibling.rs
new file mode 100644
index 000000000..83781c5e5
--- /dev/null
+++ b/tests/ui/union/union-borrow-move-parent-sibling.rs
@@ -0,0 +1,96 @@
+// revisions: mirunsafeck thirunsafeck
+// [thirunsafeck]compile-flags: -Z thir-unsafeck
+
+#![allow(unused)]
+
+use std::ops::{Deref, DerefMut};
+use std::mem::ManuallyDrop;
+
+#[derive(Default)]
+struct MockBox<T> {
+    value: [T; 1],
+}
+
+impl<T> MockBox<T> {
+    fn new(value: T) -> Self { MockBox { value: [value] } }
+}
+
+impl<T> Deref for MockBox<T> {
+    type Target = T;
+    fn deref(&self) -> &T { &self.value[0] }
+}
+
+impl<T> DerefMut for MockBox<T> {
+    fn deref_mut(&mut self) -> &mut T { &mut self.value[0] }
+}
+
+#[derive(Default)]
+struct MockVec<T> {
+    value: [T; 0],
+}
+
+impl<T> MockVec<T> {
+    fn new() -> Self { MockVec { value: [] } }
+}
+
+impl<T> Deref for MockVec<T> {
+    type Target = [T];
+    fn deref(&self) -> &[T] { &self.value }
+}
+
+impl<T> DerefMut for MockVec<T> {
+    fn deref_mut(&mut self) -> &mut [T] { &mut self.value }
+}
+
+
+union U {
+    x: ManuallyDrop<((MockVec<u8>, MockVec<u8>), MockVec<u8>)>,
+    y: ManuallyDrop<MockBox<MockVec<u8>>>,
+}
+
+fn use_borrow<T>(_: &T) {}
+
+unsafe fn parent_sibling_borrow() {
+    let mut u = U { x: ManuallyDrop::new(((MockVec::new(), MockVec::new()), MockVec::new())) };
+    let a = &mut (*u.x).0;
+    let b = &u.y; //~ ERROR cannot borrow `u` (via `u.y`)
+    use_borrow(a);
+}
+
+unsafe fn parent_sibling_move() {
+    let u = U { x: ManuallyDrop::new(((MockVec::new(), MockVec::new()), MockVec::new())) };
+    let a = u.x.0; //~ERROR cannot move out of dereference
+    let a = u.x;
+    let b = u.y; //~ ERROR use of moved value: `u`
+}
+
+unsafe fn grandparent_sibling_borrow() {
+    let mut u = U { x: ManuallyDrop::new(((MockVec::new(), MockVec::new()), MockVec::new())) };
+    let a = &mut ((*u.x).0).0;
+    let b = &u.y; //~ ERROR cannot borrow `u` (via `u.y`)
+    use_borrow(a);
+}
+
+unsafe fn grandparent_sibling_move() {
+    let u = U { x: ManuallyDrop::new(((MockVec::new(), MockVec::new()), MockVec::new())) };
+    let a = (u.x.0).0; //~ERROR cannot move out of dereference
+    let a = u.x;
+    let b = u.y; //~ ERROR use of moved value: `u`
+}
+
+unsafe fn deref_sibling_borrow() {
+    let mut u = U { y: ManuallyDrop::new(MockBox::default()) };
+    let a = &mut *u.y;
+    let b = &u.x; //~ ERROR cannot borrow `u` (via `u.x`)
+    use_borrow(a);
+}
+
+unsafe fn deref_sibling_move() {
+    let u = U { x: ManuallyDrop::new(((MockVec::new(), MockVec::new()), MockVec::new())) };
+    // No way to test deref-move without Box in union
+    // let a = *u.y;
+    // let b = u.x; ERROR use of moved value: `u`
+}
+
+
+fn main() {}