typejoin on Missing

[bkamins]

Currently:

julia> typejoin(Int, Missing)
Any

This is OK, but I guess we want Missing to be handled in a special way and it could be considered that typejoin returned Union{Int, Missing}. Any thoughts?

The rationale is that now unique with Missing union returns array of Any (and maybe there are other similar situations in other places):

julia> unique([missing,1, missing, 2, missing])
3-element Array{Any,1}:
  missing
 1
 2

This is not a huge problem, but it could be cleaner.

[nalimilan]

Precisely. See JuliaLang/julia#24332. I'll update it once Missing will be merged in Base.

[bkamins]

Close this issue then or keep for a reference?

[nalimilan]

Given that there's an issue in Base, let's close this one.