private void checkExpression(GrExpression expression) {
      if (!isBoolean(expression)) {
        return;
      }
      if (isParentBoolean(expression)) {
        return;
      }
      final int numTerms = countTerms(expression);
      if (numTerms <= getLimit()) {
        return;
      }
      registerError(expression);
    }
private void checkExpression(GrExpression expression)