Add a feature gate test for #[optimize]

src/test/ui/feature-gate-optimize_attribute.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.
+#![crate_type="rlib"]
+#![optimize(speed)] //~ ERROR #54882
+
+#[optimize(size)] //~ ERROR #54882
+mod module {
+
+#[optimize(size)] //~ ERROR #54882
+fn size() {}
+
+#[optimize(speed)] //~ ERROR #54882
+fn speed() {}
+
+#[optimize(banana)] //~ ERROR #54882
+fn not_known() {}
+
+}