pe (TyApp (TyCon "MVar#") [x,y])     = "mkMVarPrimTy " ++ ppType x 
                                           ++ " " ++ ppType y
ppT
ppType (TyApp (TyCon "MVar#") [x,y])     = "mkMVarPrimTy " ++ ppType x 
                                           ++ " " ++ ppType y
ppType (TyApp (TyCon "MVar#") [x,y])     = "mkMVarPrimTy " ++ ppType x 
                                           ++ " " ++ ppType y