@Override
    void iteration(CFGBuilder builder) {
      // Null values are not tolerated
      // Null keys are not tolerated for immutable maps
      builder.dup()
             .invokeFunction(1, myKeyExtractor, myImmutable ? Nullability.NOT_NULL : Nullability.NULLABLE)
             .pop()
             .invokeFunction(1, myValueExtractor, Nullability.NOT_NULL);
      if (myMerger != null) {
        builder.pushUnknown()
               .ifConditionIs(true)
               .pop()
               .push(DfTypes.NOT_NULL_OBJECT)
               .dup()
               .invokeFunction(2, myMerger)
               .end();
      }
      // Actual addition of Map element is unnecessary for current analysis
      builder.flush(SpecialField.COLLECTION_SIZE.createValue(builder.getFactory(), myResult)).pop();
    }
@Override
    void iteration(CFGBuilder builder)