+// Copyright 2017 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.
+
+
+struct MyStruct {
+ n: usize
+}
+
+impl MyStruct {
+ #[must_use]
+ fn need_to_use_this_method_value(&self) -> usize {
+ self.n
+ }
+}
+
+#[must_use="it's important"]
+fn need_to_use_this_value() -> bool {
+ false
+}
+
+fn main() {
+ need_to_use_this_value();
+
+ let m = MyStruct { n: 2 };
+ m.need_to_use_this_method_value();
+}