The following crate no longer compiles as of the most recent nightly. The relevant commit range is f7af19c27...bdfd698f3. Mentioning @petrochenkov @matthewjasper because #63535 sounds relevant – is this an intentional change? #### Cargo.toml ```toml [package] name = "repro" version = "0.0.0" edition = "2018" publish = false [lib] proc-macro = true ``` #### src/lib.rs ```rust extern crate proc_macro; use proc_macro::TokenStream; #[proc_macro_derive(repro)] pub fn d(_input: TokenStream) -> TokenStream { "macro_rules! m {()=>{}}".parse().unwrap() } ``` #### src/main.rs ```rust #[derive(repro::repro)] pub struct S; m!(); fn main() {} ``` --- ```console $ cargo +stable check Compiling repro v0.0.0 Finished dev [unoptimized + debuginfo] target(s) in 0.18s $ cargo +nightly-2019-08-16 check Compiling repro v0.0.0 Finished dev [unoptimized + debuginfo] target(s) in 0.18s $ cargo +nightly-2019-08-17 check Compiling repro v0.0.0 error: cannot find macro `m!` in this scope --> src/main.rs:4:1 | 4 | m!(); | ^ | = help: have you added the `#[macro_use]` on the module/import? ```