untidy_warns = map untidy_exhaustive warns
shadowed_eqns = [eqn | (eqn,i) <- qs `zip` [1..],
not (i `elementOfUniqSet` used_nos)]
untidy_warns = map untidy_exhaustive warns
shadowed_eqns = [eqn | (eqn,i) <- qs `zip` [1..],
not (i `elementOfUniqSet` used_nos)]