Adapt to changes in TypeRep complete patterns

GHC merge request !963 improved warnings in the presence of
COMPLETE annotations. This allows the removal of the Fun pattern
from the complete set.

This patch accounts for the resulting changes in pattern match warnings.

Author: sheaf

src/Data/Binary/Class.hs

@@ -994,9 +994,6 @@ instance Binary TypeLitSort where
           _ -> fail "GHCi.TH.Binary.putTypeLitSort: invalid tag"
 
 putTypeRep :: TypeRep a -> Put
--- Special handling for TYPE, (->), and RuntimeRep due to recursive kind
--- relations.
--- See Note [Mutually recursive representations of primitive types]
 putTypeRep rep  -- Handle Type specially since it's so common
   | Just HRefl <- rep `eqTypeRep` (typeRep :: TypeRep Type)
   = put (0 :: Word8)
@@ -1008,10 +1005,17 @@ putTypeRep (App f x) = do
     put (2 :: Word8)
     putTypeRep f
     putTypeRep x
+#if __GLASGOW_HASKELL__ < 903
+-- N.B. This pattern never matches,
+-- even on versions of GHC older than 9.3:
+-- a `Fun` typerep will match with the `App` pattern.
+-- This match is kept solely for pattern-match warnings,
+-- which are incorrect on GHC prior to 9.3.
 putTypeRep (Fun arg res) = do
     put (3 :: Word8)
     putTypeRep arg
     putTypeRep res
+#endif
 
 getSomeTypeRep :: Get SomeTypeRep
 getSomeTypeRep = do
@@ -1039,14 +1043,6 @@ getSomeTypeRep = do
                        [ "Applied type: " ++ show f
                        , "To argument:  " ++ show x
                        ]
-        3 -> do SomeTypeRep arg <- getSomeTypeRep
-                SomeTypeRep res <- getSomeTypeRep
-                case typeRepKind arg `eqTypeRep` (typeRep :: TypeRep Type) of
-                  Just HRefl ->
-                      case typeRepKind res `eqTypeRep` (typeRep :: TypeRep Type) of
-                        Just HRefl -> return $ SomeTypeRep $ Fun arg res
-                        Nothing -> failure "Kind mismatch" []
-                  Nothing -> failure "Kind mismatch" []
         _ -> failure "Invalid SomeTypeRep" []
   where
     failure description info =