Fix actions

.github/workflows/haskell.yml

@@ -9,12 +9,9 @@ jobs:
 
     steps:
     - uses: actions/checkout@master
-    - name: Install GHC
-      run: |
-        curl https://gitlab.haskell.org/haskell/ghcup/raw/master/bootstrap-haskell -sSf | sh
+    - uses: haskell-actions/setup@v2
     - name: Build
       run: |
-        source ~/.ghcup/env
         cabal v2-configure --enable-tests
         cabal v2-build
         mkdir out

src/AppKit.hs

@@ -5,6 +5,7 @@ module AppKit where
 
 import Control.Exception (finally, handle, SomeException(..))
 import Control.Monad.Cont
+import Control.Monad.IO.Class (liftIO)
 import Data.ByteString (useAsCString)
 import Data.Text (Text)
 import qualified Data.Text.Encoding as Text

src/Main.hs

@@ -10,6 +10,7 @@ import Control.Concurrent
 import Control.Concurrent.Async
 import Control.Monad
 import Control.Monad.Cont
+import Control.Monad.IO.Class (liftIO)
 import Data.Aeson ((.:), (<?>))
 import qualified Data.Aeson as JSON
 import qualified Data.Aeson.Types as JSON