diff --git a/.github/workflows/haskell.yml b/.github/workflows/haskell.yml
index 780c695e..4747ba0a 100644
--- a/.github/workflows/haskell.yml
+++ b/.github/workflows/haskell.yml
@@ -14,7 +14,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        ghc-version: ['9.10', '9.8', '9.6', '9.4', '9.2']
+        ghc-version: ['9.12', '9.10', '9.8', '9.6', '9.4']
         # Unlikely that we'll succeed on windows and fail on macos,
         # including it is just burning CI time. But windows could have
         # path or IO issues, so worth including
diff --git a/cabal.project b/cabal.project
index 2f39ffe2..8b227a46 100644
--- a/cabal.project
+++ b/cabal.project
@@ -1,4 +1,4 @@
-index-state: 2024-12-23T14:00:00Z
+index-state: 2025-06-07T00:00:00Z
 
 packages:
          ./lsp
@@ -13,7 +13,5 @@ benchmarks: True
 package lsp
   flags: +demo
 
-package lsp-types
-  -- This makes a big difference here as lsp-types
-  -- has very many independent modules
-  ghc-options: -j4
+-- Useful if available
+semaphore: true
diff --git a/flake.lock b/flake.lock
index d55bd4d9..1bb5e271 100644
--- a/flake.lock
+++ b/flake.lock
@@ -34,11 +34,11 @@
     },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1739446958,
-        "narHash": "sha256-+/bYK3DbPxMIvSL4zArkMX0LQvS7rzBKXnDXLfKyRVc=",
+        "lastModified": 1749143949,
+        "narHash": "sha256-QuUtALJpVrPnPeozlUG/y+oIMSLdptHxb3GK6cpSVhA=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "2ff53fe64443980e139eaa286017f53f88336dd0",
+        "rev": "d3d2d80a2191a73d1e86456a751b83aa13085d7d",
         "type": "github"
       },
       "original": {
diff --git a/lsp/src/Language/LSP/Server/Core.hs b/lsp/src/Language/LSP/Server/Core.hs
index c2b9230c..9b7fda38 100644
--- a/lsp/src/Language/LSP/Server/Core.hs
+++ b/lsp/src/Language/LSP/Server/Core.hs
@@ -322,7 +322,8 @@ defaultOptions = def
  it is parameterized over a config type variable representing the type for the
  specific configuration data the language server needs to use.
 -}
-data ServerDefinition config = forall m a.
+data ServerDefinition config
+  = forall m a.
   ServerDefinition
   { defaultConfig :: config
   -- ^ The default value we initialize the config variable to.