I'm trying to work on monoidal-functors, but although nix build succeeds, doing cabal build either from nix develop or my shell with direnv and use flake fails with

unknown package: these (dependency of monoidal-functors)

Hello there, while having a conversation with my coincidentally named counterpart (i remember that), I discovered that haskell packages set has a at least a few packages that we should really not ship, as they has been removed after a report on the [https://github.com/haskell-infra/hackage-trustees/issues/132](hackage-trustees ' Spam/fraudulent issue)

While both examples sigmaSquadron gave me are marked as broken, this is due to dependency mismatch, not that the source is gone, because we have it cached.

$ cabal v1-build
Warning: No remote package servers have been specified. Usually you would have
one specified in the config file.
Resolving dependencies...
Warning: solver failed to find a solution:
Could not resolve dependencies:
[__0] trying: AoC-0.1.0.0 (user goal)
[__1] unknown package: matrix (dependency of AoC)
[__1] fail (backjumping, conflict set: AoC, matrix)
After searching the rest of the dependency tree exhaustively, these were the
goals I've had most trouble fulfilling: AoC, matrix
Trying configure anyway.
Configuring AoC-0.1.0.0...
Error: [Cabal-8010]
Encountered missing or private dependencies:
    extra (missing), matrix (missing)

1 $ cabal v2-build
Warning: No remote package servers have been specified. Usually you would have
one specified in the config file.
Resolving dependencies...
Error: [Cabal-7107]
Could not resolve dependencies:
[__0] trying: AoC-0.1.0.0 (user goal)
[__1] unknown package: matrix (dependency of AoC)
[__1] fail (backjumping, conflict set: AoC, matrix)
After searching the rest of the dependency tree exhaustively, these were the goals I've had most trouble fulfilling: AoC, matrix

{
  pkgs ? import <nixpkgs> { },
}:
pkgs.haskellPackages.shellFor {
  name = "AoC";
  packages = h: [
    h.extra
    h.matrix
  ];
  nativeBuildInputs = [
    # Python
    # ...
    # Rust
    # ...
    # Haskell
    pkgs.cabal-install
    pkgs.haskell-language-server
    pkgs.haskellPackages.cabal-fmt
  ];
}