rust/src/test/compile-fail/extfmt-non-literal.rs

// Copyright 2012 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.

// error-pattern: literal

fn main() {
    // fmt!'s first argument must be a literal.  Hopefully this
    // restriction can be eased eventually to just require a
    // compile-time constant.
    let x = fmt!("a" + "b");
}