Preparation for GHC-9.0 (#78)

This fixes some would-be warnings in GHC-9.0
that we're going to switch to once
#76 is merged.

src/IC/Purify.hs

@@ -7,11 +7,12 @@ module IC.Purify where
 
 import Control.Monad.ST
 import Data.Functor
+import Data.Kind (Type)
 import Data.Either
 import Data.Bifunctor
 
 class SnapshotAble i where
-  type SnapshotOf i :: *
+  type SnapshotOf i :: Type
   persist :: i s -> ST s (SnapshotOf i)
   recreate :: SnapshotOf i -> ST s (i s)
 

src/IC/Test/Agent.hs

@@ -44,7 +44,6 @@ import Numeric.Natural
 import Data.Char
 import Test.Tasty.HUnit
 import Test.Tasty.Options
-import Control.Monad.Trans
 import Control.Monad.Except
 import Control.Concurrent
 import Control.Exception (catch)
@@ -128,7 +127,7 @@ connect :: String -> Int -> IO ReplWrapper
 connect ep tp = do
     agentConfig <- makeAgentConfig ep tp
     let ?agentConfig = agentConfig
-    return (R id)
+    return (R $ \x -> x)
 
 -- Yes, implicit arguments are frowned upon. But they are also very useful.
 

src/IC/Wasm/Winter/Persist.hs

@@ -27,6 +27,7 @@ import qualified Data.IntMap as IM
 import qualified Data.Map.Lazy as M
 import qualified Data.Vector as V
 import Data.ByteString.Lazy (ByteString)
+import Data.Kind (Type)
 
 import qualified IC.Canister.StableMemory as Stable
 
@@ -56,8 +57,8 @@ resumeMemory :: W.MemoryInst (ST s) -> ByteString -> ST s ()
 resumeMemory i p = resume i p
 
 class Monad (M a) => Persistable a where
-  type Persisted a :: *
-  type M a :: * -> *
+  type Persisted a :: Type
+  type M a :: Type -> Type
   persist :: a -> M a (Persisted a)
   resume :: a -> Persisted a -> M a ()