// Copyright 2016 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. extern crate proc_macro; #[proc_macro_derive(Foo)] //~^ ERROR: only usable with crates of the `proc-macro` crate type pub fn foo(a: proc_macro::TokenStream) -> proc_macro::TokenStream { a } // Issue #37590 #[proc_macro_derive(Foo)] //~^ ERROR: the `#[proc_macro_derive]` attribute may only be used on bare functions pub struct Foo { } fn main() {}