Building with MSRV on PyO3 0.12.2 fails on wrap_pyfunction!

[mtreinish]

🐛 Bug Reports

When reporting a bug, please provide the following information. If this is not a bug report you can just discard this template.

🌍 Environment

• Your operating system and version: Linux
• Your python version: 3.8
• How did you install python (e.g. apt or pyenv)? Did you use a virtualenv?: distro package
• Your Rust version (rustc --version): 1.39.0
• Your PyO3 version: 0.12.2
• Have you tried using latest PyO3 master (replace version = "0.x.y" with git = "https://github.com/PyO3/pyo3")?: No (since the release came out just a few minutes ago)

💥 Reproducing

Trying to upgrade my project to use the latest pyo3 and rust-numpy in Qiskit/rustworkx#139 I'm hitting a failure on the MSRV job:

https://github.com/Qiskit/retworkx/pull/139/checks?check_run_id=1244122021#step:6:255

error[E0658]: procedural macros cannot be expanded to expressions
   --> src/generators.rs:527:19
    |
527 |     m.add_wrapped(wrap_pyfunction!(cycle_graph))?;
    |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: for more information, see https://github.com/rust-lang/rust/issues/54727
    = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)

All the uses of m.add_wrapped(wrap_pyfunction!( is failing to compile with the same error. This works fine on rust 1.47.0, and only fails in the msrv job. I've not changed any code in the module setup around wrapping pyfunctions and it works fine on 0.11.1 with 1.39.0.

[davidhewitt]

Hmm, thanks for reporting. This is almost certainly caused by #1204, which passes on our CI. Let me see if I can figure out why, and release a fix...

[davidhewitt]

Fixed in #1234