Support GHC 9.12.4

[andreasabel]

Does the released HLS support GHC 9.12.4 yet?

$ ghcup set ghc 9.12.4
...
[ Warn  ] GHC-9.12.4 appears to have no corresponding HLS-2.13.0.0 binary.
[ ...   ] Haskell IDE support may not work.
[ ...   ] You can try to either: 
[ ...   ]   1. Install a different HLS version (e.g. downgrade for older GHCs)
[ ...   ]   2. Install and set one of the following GHCs: [9.14.1, 9.12.2, 9.10.3, 9.8.4, 9.6.7]
[ ...   ]   3. Let GHCup compile HLS for you, e.g. run: ghcup compile hls -g 2.13.0.0 --ghc 9.12.4 --cabal-update
[ ...   ]      (see https://www.haskell.org/ghcup/guide/#hls for more information)
[ Info  ] GHC 9.12.4 successfully set as default version

$ haskell-language-server-wrapper
...
Tool versions found on the $PATH
cabal:          3.16.1.0
stack:          3.9.3
ghc:            9.12.4


Consulting the cradle to get project GHC version...
2026-04-08T14:32:09.549346Z | Debug | cabal --numeric-version
2026-04-08T14:32:10.598736Z | Debug | cabal path --output-format=json
2026-04-08T14:32:10.658518Z | Debug | /Users/abela/.ghcup/bin/ghc --numeric-version
Project GHC version: 9.12.4
haskell-language-server exe candidates: ["haskell-language-server-9.12.4","haskell-language-server"]
Failed to find a HLS version for GHC 9.12.4
Executable names we failed to find: haskell-language-server-9.12.4,haskell-language-server

[fendor]

Hi!

You can compile HLS 2.13.0.0 from source to use it with GCH 9.12.4. via:

ghcup compile hls -v 2.13.0.0 --ghc 9.12.4

There are currently no bindists, but we are planning to release HLS 2.14.0.0 soon.