// 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 <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(custom_attribute, rustc_attrs)]

macro_rules! mac {
    {} => {
        #[cfg(attr)]
        mod m {
            #[lang_item]
            fn f() {}

            #[cfg_attr(target_thread_local, custom)]
            fn g() {}
        }
    }
}

mac! {}

#[rustc_error]
fn main() {} //~ ERROR compilation successful

// 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 <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(rustc_attrs)]

macro_rules! mac {
    {} => {
        #[cfg(attr)]
        mod m {
            #[lang_item]
            fn f() {}
        }
    }
}

mac! {}

#[rustc_error]
fn main() {} //~ ERROR compilation successful

--- 
+++ 
@@ -8,7 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-#![feature(rustc_attrs)]
+#![feature(custom_attribute, rustc_attrs)]
 
 macro_rules! mac {
     {} => {
@@ -16,6 +16,9 @@
         mod m {
             #[lang_item]
             fn f() {}
+
+            #[cfg_attr(target_thread_local, custom)]
+            fn g() {}
         }
     }
 }
Test that a feature gated cfg variable in a `cfg_attr` on an unconfigured item is allowed
