rust/src/test/compile-fail/issue-6596.rs

// Copyright 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.

#[feature(macro_rules)];

// error-pattern: unknown macro variable `nonexistent`

macro_rules! e(
    ($inp:ident) => (
        $nonexistent
    );
)

fn main() {
    e!(foo);
}