Add regression for #18767

Author: bkoropoff

src/test/run-pass/issue-18767.rs

@@ -0,0 +1,18 @@
+// Copyright 2014 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.
+
+// Test that regionck uses the right memcat for patterns in for loops
+// and doesn't ICE.
+
+fn main() {
+    for &&x in Some(&0u).iter() {
+        assert_eq!(x, 0)
+    }
+}