src/test/ui/issue-43023.rs

// 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 S;

impl S {
    #[derive(Debug)] //~ ERROR `derive` may only be applied to structs, enums and unions
    fn f() {
        file!();
    }
}

trait Tr1 {
    #[derive(Debug)] //~ ERROR `derive` may only be applied to structs, enums and unions
    fn f();
}

trait Tr2 {
    #[derive(Debug)] //~ ERROR `derive` may only be applied to structs, enums and unions
    type F;
}