Fix LLVM assertion on out-of-bounds const slice index.

This turned up as part of #3170.  When constructing an `undef` value to
return in the error case, we were trying to get the element type of the
Rust-level value being indexed instead of the underlying array; when
indexing a slice, that's not an array and the LLVM assertion failure
reflects this.

The regression test is a lightly altered copy of `const-array-oob.rs`.

1 files changed, 16 insertions, 0 deletions

diff --git a/src/test/compile-fail/const-slice-oob.rs b/src/test/compile-fail/const-slice-oob.rs
new file mode 100644
index 00000000000..519c4917c71
--- /dev/null
+++ b/src/test/compile-fail/const-slice-oob.rs
@@ -0,0 +1,16 @@
+// 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.
+
+const FOO: &'static[u32] = &[1, 2, 3];
+const BAR: u32 = FOO[5]; //~ ERROR const index-expr is out of bounds
+
+fn main() {
+    let _ = BAR;
+}