libsyntax: Forbid ~mut and ~const. rs=demuting

src/test/compile-fail/mutable-huh-unique-assign.rs

@@ -1,19 +0,0 @@
-// Copyright 2012 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() {
-    fn f(&&v: ~const int) {
-        *v = 1 //~ ERROR assigning to dereference of const ~ pointer
-    }
-
-    let v = ~0;
-
-    f(v);
-}