Random.gentype was introduced in #27756, so that custom random samplers would not have to use Base.eltype for returning element types, but the former falls back to the latter.

In the discussion of the recent docs cleanup PR #31787 it was unclear whether to make Random.gentype part of the API.

It would be great to decide

• whether Random.gentype(sampler) or Base.eltype(sampler) should be the API for querying typeof(rand(sampler)), especially if sampler is not a collection.
• whether Random.gentype is needed at all, or should be removed from the internal code, too.

@rfourquet, please comment.