rust/tests/ui/auxiliary/proc_macro_attr.rs
2020-05-26 16:52:02 +02:00

37 lines
1.1 KiB
Rust

// no-prefer-dynamic
#![crate_type = "proc-macro"]
#![feature(repr128, proc_macro_hygiene, proc_macro_quote)]
#![allow(clippy::useless_conversion)]
extern crate proc_macro;
extern crate quote;
extern crate syn;
use proc_macro::TokenStream;
use quote::{quote, quote_spanned};
use syn::parse_macro_input;
use syn::{parse_quote, ItemTrait, TraitItem};
#[proc_macro_attribute]
pub fn fake_async_trait(_args: TokenStream, input: TokenStream) -> TokenStream {
let mut item = parse_macro_input!(input as ItemTrait);
for inner in &mut item.items {
if let TraitItem::Method(method) = inner {
let sig = &method.sig;
let block = &mut method.default;
if let Some(block) = block {
let brace = block.brace_token;
let my_block = quote_spanned!( brace.span => {
// Should not trigger `empty_line_after_outer_attr`
#[crate_type = "lib"]
#sig #block
Vec::new()
});
*block = parse_quote!(#my_block);
}
}
}
TokenStream::from(quote!(#item))
}