rust/tests/ui/suggestions/auxiliary/issue-61963.rs
2023-01-11 09:32:08 +00:00

42 lines
1.4 KiB
Rust

// force-host
// no-prefer-dynamic
#![crate_type = "proc-macro"]
extern crate proc_macro;
use proc_macro::{Group, Spacing, Punct, TokenTree, TokenStream};
// This macro exists as part of a reproduction of #61963 but without using quote/syn/proc_macro2.
#[proc_macro_attribute]
pub fn dom_struct(_: TokenStream, input: TokenStream) -> TokenStream {
// Construct the expected output tokens - the input but with a `#[derive(DomObject)]` applied.
let attributes: TokenStream =
"#[derive(DomObject)]".to_string().parse().unwrap();
let output: TokenStream = attributes.into_iter()
.chain(input.into_iter()).collect();
let mut tokens: Vec<_> = output.into_iter().collect();
// Adjust the spacing of `>` tokens to match what `quote` would produce.
for token in tokens.iter_mut() {
if let TokenTree::Group(group) = token {
let mut tokens: Vec<_> = group.stream().into_iter().collect();
for token in tokens.iter_mut() {
if let TokenTree::Punct(p) = token {
if p.as_char() == '>' {
*p = Punct::new('>', Spacing::Alone);
}
}
}
let mut stream = TokenStream::new();
stream.extend(tokens);
*group = Group::new(group.delimiter(), stream);
}
}
let mut output = TokenStream::new();
output.extend(tokens);
output
}