ppr_co p (TcTyConAppCo r tc cos) = pprTcApp   p ppr_co tc cos <> ppr_role r
ppr_co p (TcTyConAppCo r tc cos) = pprTcApp   p ppr_co tc cos <> ppr_role r
ppr_co p (TcTyConAppCo r tc cos) = pprTcApp   p ppr_co tc cos <> ppr_role r