docs: public List<String> getBoundVariablesInScope(final BaseSingleFieldConstraint con) {
          final List<String> result = new ArrayList<String>();
          for (int i = 0; i < this.lhs.length; i++) {
              IPattern pat = this.lhs[i];
              if (findBoundVariableNames(con,
                                         result,
                                         pat)) {
                  return result;
              }
          }
          return result;
      }