Added incremental test for interlinking static references.

Author: Alexander Regueiro

src/test/incremental/static_refering_to_other_static3/issue.rs

@@ -0,0 +1,25 @@
+// Copyright 2018 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.
+
+// revisions:rpass1 rpass2
+
+#[cfg(rpass1)]
+pub static A: u8 = 42;
+#[cfg(rpass2)]
+pub static A: u8 = 43;
+
+static B: &u8 = &C.1;
+static C: (&&u8, u8) = (&B, A);
+
+fn main() {
+    assert_eq!(*B, A);
+    assert_eq!(**C.0, A);
+    assert_eq!(C.1, A);
+}