Rust error when running Mercurial tests

[PIERRE AUGIER]

Hi,

I try to run Mercurial tests from the mercurial-devel repository and I get an error related to Rust. I'm using rustc 1.81.0-nightly (24d2ac0b5 2024-07-15) and I obtain:

   Compiling proc-macro2 v1.0.47
   Compiling quote v1.0.21
   Compiling unicode-ident v1.0.5
   Compiling syn v1.0.109
   Compiling typenum v1.15.0
error[E0635]: unknown feature `proc_macro_span_shrink`
  --> /home/runner/.cargo/registry/src/index.crates.io-6f17d22bba15001f/proc-macro2-1.0.47/src/lib.rs:92:30
   |
92 |     feature(proc_macro_span, proc_macro_span_shrink)
   |                              ^^^^^^^^^^^^^^^^^^^^^^

How can I avoid this error?

Regards,
Pierre