rust/src/test/compile-fail/issue-18343.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.

struct Obj<F> where F: FnMut() -> u32 {
    closure: F,
}

fn main() {
    let o = Obj { closure: || 42 };
    o.closure(); //~ ERROR no method named `closure` found
    //~^ NOTE use `(o.closure)(...)` if you meant to call the function stored in the `closure` field
}