// returns comments
static LS gazelle_proposeVarDiscriminators(ai_gazelle_analyzeStatementsForRule_Data data) {
  LS discriminators = ll(f isInteger);
  new LS out;
  varLoop: for (S var : data.usedVars) {
    Pair<Set<S>> p = gazelle_goodAndBadValuesForVariable(data, var);
    if (nempty(p.a) && nempty(p.b))
      for (S discriminator : discriminators) pcall {
        if (scoreDiscriminator(discriminator, p).allCorrect()) {
          out.add(format("var " + quote(var) + " should satisfy *", discriminator));
          continue varLoop;
        }
      }
  }
  ret out;
}