Add test for expanding doc strings in macros.

src/test/run-pass/macro-attribute-expansion.rs

@@ -0,0 +1,29 @@
+// Copyright 2013-2014 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.
+
+// ignore-pretty - token trees can't pretty print
+
+#![feature(macro_rules)]
+
+macro_rules! descriptions {
+    ($name:ident is $desc:expr) => {
+        // Check that we will correctly expand attributes
+        #[doc = $desc]
+        #[allow(dead_code)]
+        const $name : &'static str = $desc;
+    }
+}
+
+// item
+descriptions!(DOG is "an animal")
+descriptions!(RUST is "a language")
+
+pub fn main() {
+}