(How) can I evaluate, whether a field has a future or not?
You have started well by looking for recently published papers. If there are none, it could mean your field is very small and you will find it hard to get future jobs and funding or that you are not searching in the best places. Maybe you could ask the professor if he can recommend any more recent papers for you to read to "understand the current progress and see if it matches what you want to do" or something like that. If he says nothing has been published more recently you can ask why. 

You could also ask about or search for conferences or meetings. It may be a field that does not produce lots of papers but still has a large community of active researchers, so would not seem "dead".

If your University has cut funding in that area it will definitely be harder to get a PhD there after your Masters in the same topic.

But it is an important point that the topic of your Masters doesn't have to relate directly to your PhD or future career. It's a good chance to try out an area you might be interested and see if it suits you, and in any topic you will learn research skills that can be put to good use in a PhD. I know many people who started PhDs in subjects they had never studied before, but you must show that you can learn new things quickly and have all the other "soft skills" of research: writing and presenting, finding and citing good sources, data analysis, critical thinking, using any relevant software or machinery... these will depend on your subject area.

You would probably produce much better work in your Masters project by taking the option you are most interested in. You can then have time to get familiar with the academic community, let your supervisor know you are thinking about the future and want to find out what it is like, and if it is a dead end you can take a different subject for your PhD so long as you are not missing any core skills.

Good luck!