(ty_tvs, _, _) <- tcInstType return ty
(ty_tvs', _, ty') <- tcInstType (mapM tcInstTyVar) ty
(_, _, rtti_ty') <- tcInstType (mapM tcInstTyVar) (sigmaType rtti_ty)
- getLIE(boxyUnify rtti_ty' ty')
+ _ <- getLIE(boxyUnify rtti_ty' ty')
tvs1_contents <- zonkTcTyVars ty_tvs'
let subst = (uncurry zipTopTvSubst . unzip)
[(tv,ty) | (tv,ty) <- zip ty_tvs tvs1_contents
text " in presence of newtype evidence " <> ppr new_tycon)
vars <- mapM (newVar . tyVarKind) (tyConTyVars new_tycon)
let ty' = mkTyConApp new_tycon vars
- liftTcM (boxyUnify ty (repType ty'))
+ _ <- liftTcM (boxyUnify ty (repType ty'))
-- assumes that reptype doesn't ^^^^ touch tyconApp args
return ty'