Regression test for #9951

Closes #9951.

src/test/run-pass/issue-9951.rs

@@ -0,0 +1,28 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#![allow(unused_variables)]
+
+trait Bar {
+  fn noop(&self);
+}
+impl Bar for u8 {
+  fn noop(&self) {}
+}
+
+fn main() {
+    let (a, b) = (&5u8 as &Bar, &9u8 as &Bar);
+    let (c, d): (&Bar, &Bar) = (a, b);
+
+    let (a, b) = (Box::new(5u8) as Box<Bar>, Box::new(9u8) as Box<Bar>);
+    let (c, d): (&Bar, &Bar) = (&*a, &*b);
+
+    let (c, d): (&Bar, &Bar) = (&5, &9);
+}