pprTcCo, pprParendTcCo :: TcCoercion -> SDoc
pprTcCo       co = ppr_co TopPrec   co
pprTcCo, pprParendTcCo :: TcCoercion -> SDoc
pprTcCo       co = ppr_co TopPrec   co
pprTcCo       co = ppr_co TopPrec   co