// 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 or the MIT license // , at your // option. This file may not be copied, modified, or distributed // except according to those terms. #![warn(unused)] macro_rules! m { ($a:tt $b:tt) => { $b $a; //~ WARN struct is never used } } fn main() { m!(S struct); }