Add run-pass/never_coercions.rs test

Author: canndrew

src/test/run-pass/never_coercions.rs

@@ -0,0 +1,19 @@
+// Copyright 2012-2014 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.
+
+fn main() {
+    let v: Vec<u32> = Vec::new();
+    match 0u32 {
+        0 => &v,
+        1 => return,
+        _ => &v[..],
+    };
+}
+