diff --git a/ghcide-bench.cabal b/ghcide-bench.cabal
--- a/ghcide-bench.cabal
+++ b/ghcide-bench.cabal
@@ -2,7 +2,7 @@
 build-type:         Simple
 category:           Development
 name:               ghcide-bench
-version:            2.6.0.0
+version:            2.7.0.0
 license:            Apache-2.0
 license-file:       LICENSE
 author:             The Haskell IDE team
@@ -19,7 +19,7 @@
     location: https://github.com/haskell/haskell-language-server.git
 
 executable ghcide-bench
-    default-language: Haskell2010
+    default-language: GHC2021
     build-depends:
         aeson,
         base,
@@ -45,23 +45,13 @@
     ghc-options: -threaded -Wall -Wno-name-shadowing -rtsopts
     main-is: Main.hs
     default-extensions:
-        BangPatterns
-        DeriveFunctor
-        DeriveGeneric
-        FlexibleContexts
-        GeneralizedNewtypeDeriving
         LambdaCase
-        NamedFieldPuns
         OverloadedStrings
         RecordWildCards
-        ScopedTypeVariables
-        StandaloneDeriving
-        TupleSections
-        TypeApplications
         ViewPatterns
 
 library
-    default-language: Haskell2010
+    default-language: GHC2021
     hs-source-dirs: src
     ghc-options: -Wall -Wno-name-shadowing
     exposed-modules:
@@ -77,8 +67,7 @@
         directory,
         extra,
         filepath,
-        ghcide,
-        ghcide-test-utils,
+        ghcide:{ghcide, ghcide-test-utils},
         hashable,
         lens,
         lsp-test,
@@ -91,23 +80,13 @@
         text,
         row-types
     default-extensions:
-        BangPatterns
-        DeriveFunctor
-        DeriveGeneric
-        FlexibleContexts
-        GeneralizedNewtypeDeriving
         LambdaCase
-        NamedFieldPuns
         RecordWildCards
-        ScopedTypeVariables
-        StandaloneDeriving
-        TupleSections
-        TypeApplications
         ViewPatterns
 
 test-suite test
     type: exitcode-stdio-1.0
-    default-language: Haskell2010
+    default-language: GHC2021
     build-tool-depends:
         ghcide:ghcide,
         implicit-hie:gen-hie
@@ -119,22 +98,12 @@
         base,
         extra,
         ghcide-bench,
-        lsp-test ^>= 0.16,
+        lsp-test ^>= 0.17,
         tasty,
         tasty-hunit >= 0.10,
         tasty-rerun,
     default-extensions:
-        BangPatterns
-        DeriveFunctor
-        DeriveGeneric
-        FlexibleContexts
-        GeneralizedNewtypeDeriving
         LambdaCase
-        NamedFieldPuns
         OverloadedStrings
         RecordWildCards
-        ScopedTypeVariables
-        StandaloneDeriving
-        TupleSections
-        TypeApplications
         ViewPatterns
diff --git a/src/Experiments.hs b/src/Experiments.hs
--- a/src/Experiments.hs
+++ b/src/Experiments.hs
@@ -1,12 +1,9 @@
-{-# LANGUAGE ConstraintKinds           #-}
-{-# LANGUAGE DataKinds                 #-}
-{-# LANGUAGE ExistentialQuantification #-}
-{-# LANGUAGE GADTs                     #-}
-{-# LANGUAGE ImplicitParams            #-}
-{-# LANGUAGE ImpredicativeTypes        #-}
-{-# LANGUAGE OverloadedLabels          #-}
-{-# LANGUAGE OverloadedStrings         #-}
-{-# LANGUAGE PolyKinds                 #-}
+{-# LANGUAGE DataKinds          #-}
+{-# LANGUAGE GADTs              #-}
+{-# LANGUAGE ImplicitParams     #-}
+{-# LANGUAGE ImpredicativeTypes #-}
+{-# LANGUAGE OverloadedLabels   #-}
+{-# LANGUAGE OverloadedStrings  #-}
 {-# OPTIONS_GHC -Wno-deprecations -Wno-unticked-promoted-constructors #-}
 
 module Experiments
@@ -34,7 +31,6 @@
 import           Control.Monad.Extra                (allM, forM, forM_, forever,
                                                      unless, void, when,
                                                      whenJust, (&&^))
-import           Control.Monad.Fail                 (MonadFail)
 import           Control.Monad.IO.Class
 import           Data.Aeson                         (Value (Null),
                                                      eitherDecodeStrict',
diff --git a/test/Main.hs b/test/Main.hs
--- a/test/Main.hs
+++ b/test/Main.hs
@@ -7,7 +7,6 @@
 {-# LANGUAGE DuplicateRecordFields #-}
 {-# LANGUAGE GADTs                 #-}
 {-# LANGUAGE ImplicitParams        #-}
-{-# LANGUAGE PolyKinds             #-}
 {-# OPTIONS_GHC -Wno-deprecations -Wno-unticked-promoted-constructors #-}
 
 module Main (main) where