1 // Copyright 2020 The Bazel Authors. All rights reserved.
2 //
3 // Licensed under the Apache License, Version 2.0 (the "License");
4 // you may not use this file except in compliance with the License.
5 // You may obtain a copy of the License at
6 //
7 // http://www.apache.org/licenses/LICENSE-2.0
8 //
9 // Unless required by applicable law or agreed to in writing, software
10 // distributed under the License is distributed on an "AS IS" BASIS,
11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 // See the License for the specific language governing permissions and
13 // limitations under the License.
14
15 // This differs from the edition 2015 version because it does not have an `extern proc_macro`
16 // statement, which became optional in edition 2018.
17
18 use proc_macro::TokenStream;
19
20 /// This macro is a no-op; it is exceedingly simple as a result
21 /// of avoiding dependencies on both the syn and quote crates.
22 #[proc_macro_derive(HelloWorld)]
hello_world(_input: TokenStream) -> TokenStream23 pub fn hello_world(_input: TokenStream) -> TokenStream {
24 TokenStream::new()
25 }
26