1 files changed, 11 insertions, 0 deletions
diff --git a/tests/ui/box/unit/unique-fn-arg-mut.rs b/tests/ui/box/unit/unique-fn-arg-mut.rs
new file mode 100644
index 000000000..01510200b
--- /dev/null
+++ b/tests/ui/box/unit/unique-fn-arg-mut.rs
@@ -0,0 +1,11 @@
+// run-pass
+
+fn f(i: &mut Box<isize>) {
+    *i = Box::new(200);
+}
+
+pub fn main() {
+    let mut i = Box::new(100);
+    f(&mut i);
+    assert_eq!(*i, 200);
+}