docs: private void visit(LiteralRestrictionDescr descr) {
  
          LiteralRestriction restriction = LiteralRestriction.createRestriction(pattern,
                  descr.getText());
  
          restriction.setPatternIsNot(pattern.isPatternNot());
          restriction.setFieldPath(field.getPath());
          restriction.setOperator(Operator.determineOperator(descr.getEvaluator(),
                  descr.isNegated()));
          restriction.setOrderNumber(orderNumber);
          restriction.setParentPath(pattern.getPath());
          restriction.setParentType(pattern.getVerifierComponentType());
  
          // Set field value, if it is unset.
          field.setFieldType(restriction.getValueType());
  
          data.add(restriction);
          solvers.addPatternComponent(restriction);
      }