I discovered that quite quickly after they switched.

More importantly (for any haskell developers using Arch), there are also static builds for stack, cabal and ghcup too although you then need to maintain your own set of GHC and libraries.

I can't imagine what it must be like to use the official packages since the haskell library ecosystem is quite fast moving.

Thank you! I had noticed the same problem, but was not aware of this excellent solution. I just applied it, and it works perfectly... and I removed the dozens of Haskell libraries that were there just for Pandoc.

For anyone else interested, the same solution applies to shellcheck - just install shellcheck-bin from AUR.