Can double-ref (&&x) parsing be fixed?

This is very unfortunate.

```
fn main() {
    let x = ~~1;
    let y = &&x;
}
```

```
brian@brian-X1:~/dev/rust4/build$ x86_64-unknown-linux-gnu/stage1/bin/rustc test.rs
test.rs:3:12: 3:14 error: unexpected token: `&&`
test.rs:3     let y = &&x;
                      ^~
```

Nominating.
