In tcSplittyConApp_maybe, add the PredTy case

such that this can compile again:

    newtype Moose = MkMoose () deriving (Eq, Ord)

diff --git a/compiler/typecheck/TcType.lhs b/compiler/typecheck/TcType.lhs
index f266f4b..888452b 100644 (file)
--- a/compiler/typecheck/TcType.lhs
+++ b/compiler/typecheck/TcType.lhs
@@ -712,6 +712,8 @@ tcSplitTyConApp_maybe :: Type -> Maybe (TyCon, [Type])
 tcSplitTyConApp_maybe ty | Just ty' <- tcView ty = tcSplitTyConApp_maybe ty'
 tcSplitTyConApp_maybe (TyConApp tc tys) = Just (tc, tys)
 tcSplitTyConApp_maybe (FunTy arg res)   = Just (funTyCon, [arg,res])
+tcSplitTyConApp_maybe (AppTy arg res)   = Just (funTyCon, [arg,res])
+tcSplitTyConApp_maybe (PredTy (ClassP _ [ty']))   = tcSplitTyConApp_maybe ty'
        -- Newtypes are opaque, so they may be split
        -- However, predicates are not treated
        -- as tycon applications by the type checker