An inner doc comment //! doc currently incorrectly tokenizes as an outer attribute, #[doc = "//! doc"]. It should be an inner attribute, #![doc = " doc"]. You can see the correct behavior in macro_rules:
macro_rules! tokens {
(#![doc = $tt:tt]) => {
println!("{:?}", $tt);
}
}
fn main() {
tokens! {
//! doc
}
}Repro script
#!/bin/sh
cargo new --lib repro_macro
cargo new --lib repro
echo >repro_macro/src/lib.rs '
#![feature(proc_macro)]
extern crate proc_macro;
use proc_macro::TokenStream;
#[proc_macro]
pub fn repro(_input: TokenStream) -> TokenStream {
let mut tts = "//! doc\n".parse::<TokenStream>().unwrap().into_iter();
println!("{}", tts.next().unwrap());
println!("{}", tts.next().unwrap());
TokenStream::empty()
}
'
echo >>repro_macro/Cargo.toml '
[lib]
proc-macro = true
'
echo >repro/src/lib.rs '
#![feature(proc_macro)]
extern crate repro_macro;
repro_macro::repro!();
'
echo >>repro/Cargo.toml '
repro_macro = { path = "../repro_macro" }
'
cargo build --manifest-path repro/Cargo.toml@alexcrichton
An inner doc comment
//! doccurrently incorrectly tokenizes as an outer attribute,#[doc = "//! doc"]. It should be an inner attribute,#![doc = " doc"]. You can see the correct behavior in macro_rules:Repro script
@alexcrichton