Test keyword unreservations

Author: Havvy

src/test/run-pass/rfc-2421-unreserve-pure-offsetof-sizeof-alignof.rs

@@ -0,0 +1,22 @@
+// 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 removed keywords are allowed as identifiers.
+fn main () {
+    let offsetof = ();
+    let alignof = ();
+    let sizeof = ();
+    let pure = ();
+}
+
+fn offsetof() {}
+fn alignof() {}
+fn sizeof() {}
+fn pure() {}