I'm trying to build the hashlink crate, which is needed by a transitive
dependency of future work on Sequoia (https://sequoia-pgp.org).

However, the build of hashlink 0.6.0 fails with an error:

```
error[E0599]: no variant or associated item named `default` found for enum `DefaultHashBuilder` in the current scope
  --> src/linked_hash_map.rs:50:57
   |
50 |             hash_builder: hash_map::DefaultHashBuilder::default(),
   |                                                         ^^^^^^^ variant or associated item not found in `DefaultHashBuilder`

error[E0599]: no variant or associated item named `default` found for enum `DefaultHashBuilder` in the current scope
  --> src/linked_hash_map.rs:60:57
   |
60 |             hash_builder: hash_map::DefaultHashBuilder::default(),
   |                                                         ^^^^^^^ variant or associated item not found in `DefaultHashBuilder`

error: aborting due to 2 previous errors
```

I reported this to the hashlink project upstream, and @nathaniel-daniel
identified the problem as being the stripping of the ahash feature from
the hashbrown crate in debian.

Presumably this means that we need the ahash crate in debian first; and
then we should enable that feature for the hashbrown crate.

Package rust-ahash is now in Debian, which should help fix this bug.

 - Jonas

I looked but the new packages don't seem to be installable.

Quoting peter green (2022-05-28 14:49:00)

Yeah - as you know (since you filed the bugreport), all packages
involving librust-once-cell-dev currently fails to build from source due
to bug#1011645 :-(

I meant to say that the availability of the package is a step towards
this bugreport getting fixed - not that it was possible to fix right
now.

 - Jonas

Quoting Jonas Smedegaard (2022-05-28 16:18:26)

Thanks for the quick fix of bug#1011645.

I have now released rust-ahash with a fix for the first of the above
bugs.  I don't recognize librust-atomic-polyfill-0.1+default-dev being
declared anywhere, however.  Please double-check that you used a
pristine Debian unstable system where you experience that error, and if
it persists then please file a bugreport.

Kind regards,

 - Jonas

We believe that the bug you reported is fixed in the latest version of
rust-hashbrown, which is due to be installed in the Debian FTP archive.

A summary of the changes between this version and the previous one is
attached.

Thank you for reporting the bug, which will now be closed.  If you
have further comments please address them to 987324@bugs.debian.org,
and the maintainer will reopen the bug report if appropriate.

Debian distribution maintenance software
pp.
Peter Michael Green <plugwash@debian.org> (supplier of updated rust-hashbrown package)

(This message was generated automatically at their request; if you
believe that there is a problem with it please contact the archive
administrators by mailing ftpmaster@ftp-master.debian.org)
Format: 1.8
Date: Sun, 29 May 2022 16:45:06 +0000
Source: rust-hashbrown
Architecture: source
Version: 0.11.2-3
Distribution: unstable
Urgency: medium
Maintainer: Debian Rust Maintainers <pkg-rust-maintainers@alioth-lists.debian.net>
Changed-By: Peter Michael Green <plugwash@debian.org>
Closes: 987324
Changes:
 rust-hashbrown (0.11.2-3) unstable; urgency=medium
 .
   * Team upload.
   * Package hashbrown 0.11.2 from crates.io using debcargo 2.5.0
   * Reinstate ahash feature (Closes: 987324)
   * Add patch to make testsuite work with rand 0.8.
   * Establish baseline for tests.
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 2f75cc79f0258e3921af4eaf810af5d36e3aa0d0 9020 rust-hashbrown_0.11.2-3_source.buildinfo
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looks like we both fixed it from opposite ends :)

I copied the errors from tracker.debian.org, unfortunately
tracker.debian.org doesn't distinguish between direct and indirect
dependencies and I didn't realize that ahash had a dependency on
once-cell.

Anyway, now the dependency issues are understood/fixed, I went ahead
and reinstated the feature in hashbrown.