Add test for missing stability checker

Author: Manishearth

src/test/compile-fail/missing-stability.rs

@@ -0,0 +1,33 @@
+// Copyright 2015 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.
+
+// Checks that exported items without stability attributes cause an error
+
+#![crate_type="lib"]
+#![feature(staged_api)]
+#![staged_api]
+
+pub fn unmarked() {
+    //~^ ERROR This node does not have a stability attribute
+    ()
+}
+
+#[unstable(feature = "foo")]
+pub mod foo {
+    // #[unstable] is inherited
+    pub fn unmarked() {}
+}
+
+#[stable(feature = "bar", since="1.0.0")]
+pub mod bar {
+    // #[stable] is not inherited
+    pub fn unmarked() {}
+    //~^ ERROR This node does not have a stability attribute
+}