CodeInQuestion.hs

    let
        workRun :: (IO ([()], [IO ()]) ->  IO ([()], [IO ()])) -> IO (IO ())
        workRun restore = do
          let systemActs' = pumpAction : map getAction systemActs
          res <- try @SomeException
                 (restore $ (shakeRunDatabase shakeDb systemActs' :: IO ([()], [IO ()])))
          let res' = case res of
                      Left e -> "exception: " <> displayException e
                      Right _ -> "completed"
              -- Wrap up in a thread to avoid calling interruptible
              -- operations inside the masked section
          let wrapUp = logDebug logger $ T.pack $ "Finishing build session(" ++ res' ++ ")"
          return wrapUp

    -- Do the work in a background thread
    let myAsync :: ((IO ([()], [IO ()]) ->  IO ([()], [IO ()])) -> IO (IO ())) -> IO (Async (IO (IO ())))
        myAsync = asyncWithUnmask
    workThread <- myAsync workRun

    -- run the wrap up unmasked
    _ <- async $ join $ wait workThread

Error

[29 of 49] Compiling Development.IDE.Core.Shake ( src/Development/IDE/Core/Shake.hs, /home/munin/Documents/haskell/ghcide/dist-newstyle/build/x86_64-linux/ghc-8.11.0.20200814/ghcide-0.2.0/build/Development/IDE/Core/Shake.o )

src/Development/IDE/Core/Shake.hs:611:19: error:
    • Couldn't match type: forall b. IO b -> IO b
                     with: IO ([()], [IO ()]) -> IO ([()], [IO ()])
      Expected: ((IO ([()], [IO ()]) -> IO ([()], [IO ()]))
                 -> IO (IO ()))
                -> IO (Async (IO (IO ())))
        Actual: ((forall b. IO b -> IO b) -> IO (IO ()))
                -> IO (Async (IO ()))
    • In the expression: asyncWithUnmask
      In an equation for ‘myAsync’: myAsync = asyncWithUnmask
      In the expression:
        do actionQueue :: TQueue DelayedActionInternal <- atomically
                                                            $ do q <- newTQueue
                                                                 traverse_ (writeTQueue q) userActs
                                                                 ....
           actionInProgress :: TVar (Maybe DelayedActionInternal) <- newTVarIO
                                                                       Nothing
           let pumpAction = forever $ ...
               workRun :: (IO ([()], [IO ()]) -> IO ([()], [IO ()])) -> IO (IO ())
               ....
           let myAsync ::
                 ((IO ([()], [IO ()]) -> IO ([()], [IO ()])) -> IO (IO ()))
                 -> IO (Async (IO (IO ())))
               myAsync = asyncWithUnmask
           ....
    |
611 |         myAsync = asyncWithUnmask
    |                   ^^^^^^^^^^^^^^^
cabal: Failed to build ghcide-0.2.0 (which is required by exe:ghcide-bench
from ghcide-0.2.0).