#![feature(prelude_import)] #[prelude_import] use std::prelude::rust_2021::*; #[macro_use] extern crate std; // This differs from the edition 2015 version because it does not have an `extern proc_macro` // statement, which became optional in edition 2018. use proc_macro::TokenStream; #[proc_macro] pub fn make_answer(_item: TokenStream) -> TokenStream { "fn answer() -> u32 { 42 }".parse().unwrap() } const _: () = { extern crate proc_macro; #[rustc_proc_macro_decls] #[used] #[allow(deprecated)] static _DECLS: &[proc_macro::bridge::client::ProcMacro] = &[proc_macro::bridge::client::ProcMacro::bang("make_answer", make_answer)]; };