Program: 61839
Project: 61839
Buggy source:
@Override public List<GraphSourceItem> toSourceIgnoreReturnValue(SourceGeneratorLocalData localData,SourceGenerator generator){
  List<GraphSourceItem> ret=new ArrayList<>();
  if (object instanceof GetVariableActionItem) {
    GetVariableActionItem gv=(GetVariableActionItem)object;
    ret.addAll(gv.toSource(localData,generator));
    ret.remove(ret.size() - 1);
    ret.addAll(gv.toSource(localData,generator));
    ret.add(new ActionDecrement());
    ret.add(new ActionSetVariable());
  }
 else   if (object instanceof GetMemberActionItem) {
    GetMemberActionItem mem=(GetMemberActionItem)object;
    ret.addAll(mem.toSource(localData,generator));
    ret.remove(ret.size() - 1);
    ret.addAll(mem.toSource(localData,generator));
    ret.add(new ActionDecrement());
    ret.add(new ActionSetMember());
  }
 else   if ((object instanceof DirectValueActionItem) && ((DirectValueActionItem)object).value instanceof RegisterNumber) {
    RegisterNumber rn=(RegisterNumber)((DirectValueActionItem)object).value;
    ret.add(new ActionPush(new RegisterNumber(rn.number)));
    ret.add(new ActionDecrement());
    ret.add(new ActionStoreRegister(rn.number));
    ret.add(new ActionPop());
  }
 else   if (object instanceof GetPropertyActionItem) {
    GetPropertyActionItem gp=(GetPropertyActionItem)object;
    ret.addAll(gp.toSource(localData,generator));
    ret.remove(ret.size() - 1);
    ret.addAll(gp.toSource(localData,generator));
    ret.add(new ActionDecrement());
    ret.add(new ActionSetProperty());
  }
  return ret;
}

Fixed version (ground truth):
@Override public List<GraphSourceItem> toSourceIgnoreReturnValue(SourceGeneratorLocalData localData,SourceGenerator generator){
  List<GraphSourceItem> ret=new ArrayList<>();
  GraphTargetItem val=object;
  if (val instanceof VariableActionItem) {
    val=((VariableActionItem)val).getBoxedValue();
  }
  if (val instanceof GetVariableActionItem) {
    GetVariableActionItem gv=(GetVariableActionItem)val;
    ret.addAll(gv.toSource(localData,generator));
    ret.remove(ret.size() - 1);
    ret.addAll(gv.toSource(localData,generator));
    ret.add(new ActionDecrement());
    ret.add(new ActionSetVariable());
  }
 else   if (val instanceof GetMemberActionItem) {
    GetMemberActionItem mem=(GetMemberActionItem)val;
    ret.addAll(mem.toSource(localData,generator));
    ret.remove(ret.size() - 1);
    ret.addAll(mem.toSource(localData,generator));
    ret.add(new ActionDecrement());
    ret.add(new ActionSetMember());
  }
 else   if ((val instanceof DirectValueActionItem) && ((DirectValueActionItem)val).value instanceof RegisterNumber) {
    RegisterNumber rn=(RegisterNumber)((DirectValueActionItem)val).value;
    ret.add(new ActionPush(new RegisterNumber(rn.number)));
    ret.add(new ActionDecrement());
    ret.add(new ActionStoreRegister(rn.number));
    ret.add(new ActionPop());
  }
 else   if (val instanceof GetPropertyActionItem) {
    GetPropertyActionItem gp=(GetPropertyActionItem)val;
    ret.addAll(gp.toSource(localData,generator));
    ret.remove(ret.size() - 1);
    ret.addAll(gp.toSource(localData,generator));
    ret.add(new ActionDecrement());
    ret.add(new ActionSetProperty());
  }
  return ret;
}