In 2021 pat was changed to recognize `|` at the top level, with
pat_param added to retain the old behavior. This means
pat is subject to the same cross-edition behavior as expr will be in
2024.
Co-authored-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>
There's a subtle interaction between macros with metavar expressions and the
edition-dependent fragment matching behavior. This test illustrates the current
behavior when using macro-generating-macros across crate boundaries with
different editions.
Co-Authored-By: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>
Co-Authored-By: Eric Holk <eric@theincredibleholk.org>
