ppr_co p (TcCastCo co1 co2)      = maybeParen p FunPrec $
                                   ppr_co FunPrec co1 <+> ptext (sLit "|>") <+> ppr_co FunPrec co2
ppr_co p (TcCastCo co1 co2)      = maybeParen p FunPrec $
                                   ppr_co FunPrec co1 <+> ptext (sLit "|>") <+> ppr_co FunPrec co2
ppr_co p (TcCastCo co1 co2)      = maybeParen p FunPrec $
                                   ppr_co FunPrec co1 <+> ptext (sLit "|>") <+> ppr_co FunPrec co2