Fix vector indexing in consts so it works with the enum vector const fix.

src/test/run-pass/const-enum-vec-index.rs

@@ -0,0 +1,25 @@
+// Copyright 2013 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.
+
+enum E { V1(int), V0 }
+const C: &[E] = &[V0, V1(0xDEADBEE)];
+const C0: E = C[0];
+const C1: E = C[1];
+
+fn main() {
+    match C0 { 
+        V0 => (),
+        _ => die!()
+    }
+    match C1 {
+        V1(n) => assert(n == 0xDEADBEE),
+        _ => die!()
+    }
+}