should we close as a duplicate even though they’re different types, or
should we leave an answer saying “no you can’t” and link to the
I think we should be duping when it's appropriate, as a dupe link is more substantial/prominent than an answer. An answer could be below other higher voted answers without the link.
However, I don't believe there is a definitive answer to your question regarding "should we dupe when different types", as each scenario is very different, and decisions are case-by-case based on the specific questions and answers.
So as it's such a minefield with varying opinions and scenarios, I don't think we can discuss here to get a golden rule as to when to dupe or not if the mandatory tags are different.
When reviewing (on Meta) I do take into account when a proposed dupe has different mandatory tags, however that is never a deciding factor alone.
I sometimes choose to close or leave open based on different mandatory tags, but only in conjunction with the two questions' scopes, answers, and what the overall aims of both questions are.
The general rule on Stack Exchange sites is:
If another question does or could answer this question, it is a dupe
However this is not really true for Meta, mainly because we have discussions.
I've seen a discussion asking why something is X with an answer from Staff explaining why it's like that and why it won't ever change.
So it can be argued that a feature-request is therefore pointless as staff have already stated it won't change, so duping the feature-request to the discussion is okay, as the answer on the discussion answers the feature-request.
And some users will close as dupe based on the above.
However, it is also arguable that although the feature-request is answered in the discussion question, an open feature-request might still be viable as there may be some brilliant ideas, and with votes and counter arguments, the staff might re-think and implement the change.
Which is less likely to happen on the discussion question because its scope, and therefore the discussion is about "Why is this like that", not "should we/can we change this".
And so some users will vote to leave open based on the above.
So, users vote differently, and for very different reasons, and differently on different scenarios and questions, with or without taking into account mandatory tags.
As such, we can only discuss specific examples really.
Regarding your example
I voted to close on the example questions you linked to, and the discussion question closed as dupe is essentially:
How do I track voting activity on meta sites which do not give rep, as there is no notification?
The answer to that question is simply:
It's useful to send any users with the same request for info to a feature-request proposing to implement what they want, because they get the same info from the feature request plus more.
Being linked to the feature-request, they:
- Are told it is not possible
- Can be involved in trying to make it possible
- Can see any updates by staff for the potential implementation of their
- Won't make a (dupe) feature-request themselves
Whereas the discussion question not being duped, they are simply told: