Merge #2540

2540: Switch CI to GHC 8.10.2 r=mrBliss a=mrBliss

Update the dependencies to versions compatible with GHC 8.10.2.

Switch over CI to GHC 8.10.2.

Co-authored-by: Thomas Winant <thomas@well-typed.com>
Co-authored-by: Hamish Mackenzie <Hamish.K.Mackenzie@gmail.com>
Co-authored-by: Marcin Szamotulski <profunctor@pm.me>

io-sim-classes/src/Control/Monad/Class/MonadAsync.hs

@@ -38,7 +38,6 @@ import           Control.Monad.Reader
 import qualified Control.Monad.STM as STM
 
 import           Data.Foldable (fold)
-import           Data.Functor (void)
 import           Data.Kind (Type)
 import           Data.Proxy
 

io-sim-classes/src/Control/Monad/Class/MonadTimer.hs

@@ -25,8 +25,6 @@ import           Data.Time.Clock (DiffTime, diffTimeToPicoseconds)
 #if defined(__GLASGOW_HASKELL__) && !defined(mingw32_HOST_OS) && !defined(__GHCJS__)
 import qualified GHC.Event as GHC (TimeoutKey, getSystemTimerManager,
                      registerTimeout, unregisterTimeout, updateTimeout)
-#else
-import           Control.Monad (when)
 #endif
 
 import           Control.Monad.Class.MonadFork

io-sim/test/Test/IOSim.hs

@@ -18,7 +18,7 @@ import           Data.Time.Clock (DiffTime, picosecondsToDiffTime)
 
 import           Control.Exception (ArithException (..))
 import           Control.Monad
-import           System.IO.Error (IOError, ioeGetErrorString, isUserError)
+import           System.IO.Error (ioeGetErrorString, isUserError)
 
 import           Control.Monad.Class.MonadFork
 import           Control.Monad.Class.MonadSay