ppr_co p (TcLetCo bs co)         = maybeParen p TopPrec $
                                   sep [ptext (sLit "let") <+> braces (ppr bs), ppr co]
ppr_co p (TcLetCo bs co)         = maybeParen p TopPrec $
                                   sep [ptext (sLit "let") <+> braces (ppr bs), ppr co]
ppr_co p (TcLetCo bs co)         = maybeParen p TopPrec $
                                   sep [ptext (sLit "let") <+> braces (ppr bs), ppr co]