Fix stable hashing of AllocIds

src/test/incremental/static_stable_hash/issue-49301.rs

@@ -0,0 +1,28 @@
+// 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.
+
+// https://github.com/rust-lang/rust/issues/49081
+
+// revisions:rpass1 rpass2
+
+#[cfg(rpass1)]
+pub static A: &str = "hello";
+#[cfg(rpass2)]
+pub static A: &str = "xxxxx";
+
+#[cfg(rpass1)]
+fn main() {
+    assert_eq!(A, "hello");
+}
+
+#[cfg(rpass2)]
+fn main() {
+    assert_eq!(A, "xxxxx");
+}