feat: Add support for LSP 2

[Vekhir]

@mmhat Building upon #2531, this further adds support for

• lsp 2.1
• lsp-types 2.0
• lsp-test 0.16

This is a minimum refactoring by essentially following the compile errors and fixing them one by one without major structural changes. Most changes are just renaming.

No thoughts were given to backwards compatibility within LSP - the above versions are also the minimum requirement for dhall-lsp-server. This is consistent with GHC 9.6.

Note

I had this diff lying around for a few days and it has been verified in my build for updating Arch packages to GHC 9.6.

Supersedes #2428

[Vekhir]

@mmhat Rather obvious in hindsight, I've now updated the stack configuration to use the newer lsp libraries. Not sure what to do about the hydra/nix issue.

[mmhat]

@Vekhir Thank you for doing this! I am about to review the work you did so far. Regarding the Hydra issue: I am an ArchLinux user as well, so I faced the same problems while working on #2531 . I used the following to update packages in the Nix setup:

# We assume that the current directory is the root of the checked out work tree.
# Start a container with the work tree mounted under /work.
# (I use podman nowadays; docker should work as well.)
podman run -it --rm -v .:/work -w /work docker.io/nixos/nix
# Now we are in the container. We need to install cabal-install and cabal2nix:
nix-env -i cabal-install -i cabal2nix
# cabal2nix needs a hackage index tarball:
cabal update
# Now we generate the Nix expression for the lsp-2.1.0.0 package and store it in the right location:
cabal2nix cabal://lsp-2.1.0.0 > ./nix/packages/lsp.nix

[Vekhir]

@mmhat I've implemented your suggestions and fixed the CI build - it will hopefully pass now.

[Vekhir]

Hydra now works, lets see if the rest works now too

[Vekhir]

This check will most probably fail for GHC 8.10 since hashable 1.3.5.0 needs ghc-bignum, but I want to see the error message. If stack provides a compatible version for ghc-bignum, then we are likely done.

[Vekhir]

Failed due to typo... Fixed it now

[Vekhir]

@mmhat Looks like we are done. If you don't have any objections, you can merge it. Is there something you want/need done to make a Hackage release? Would make Arch integration easier.

[mmhat]

@Vekhir Can you please rebase your changes onto main?

Regarding a new release: Those are done by @Gabriella439 , so I think we have to be a bit more patient.

EDIT: Never mind, Github managed to merge it but the UI didn't show.

[mmhat]

@Vekhir Nice, excellent work! Thank you!

[Vekhir]

It's not urgent anyway. Thanks for your suggestions and reviewing!