itertools 0.9: `error: '#[inline]' attribute cannot be used on macro calls`

[matthiaskrgr]

git clone https://github.com/rust-itertools/itertools
cd itertools
git checkout v0.9.0
cargo build

error: `#[inline]` attribute cannot be used on macro calls
  --> src/rciter_impl.rs:54:5
   |
54 |     #[inline]
   |     ^^^^^^^^^
   |
   = help: `#[inline]` can only be applied to functions

rustc 1.91.0-nightly (46c219bd2 2025-08-22)
binary: rustc
commit-hash: 46c219bd24862c0a87f0299570bb37f2d5ecf6ce
commit-date: 2025-08-22
host: x86_64-unknown-linux-gnu
release: 1.91.0-nightly
LLVM version: 21.1.0

on beta rustc 1.90.0-beta.6 (085bdc2ae 2025-08-21)

warning: unused attribute `inline`
  --> src/rciter_impl.rs:54:5
   |
54 |     #[inline]
   |     ^^^^^^^^^
   |
note: the built-in attribute `inline` will be ignored, since it's applied to the macro invocation `clone_fields`
  --> src/rciter_impl.rs:55:5
   |
55 |     clone_fields!(rciter);
   |     ^^^^^^^^^^^^
   = note: `#[warn(unused_attributes)]` on by default

[lqd]

It seems likely that the ongoing crater run will see this as well.

[VorpalBlade]

It seems likely that the ongoing crater run will see this as well.

No? From my reading of the bug it just warns on beta but fails on nightly.

[lqd]

Ah I misread the OP sorry, it mentions the beta as a baseline for some reason.

[matthiaskrgr]

regression in #144689 cc @JonathanBrouwer

[matthiaskrgr]

possibly mvce:

fn main() {
    #[inline]
    unreachable!()
}