Sources for the Zappa Nardelli et al. subtyping implementation?

Francesco Zappa Nardelli, Julia Belyakova, Artem Pelenitsyn, Benjamin Chung, Jeff Bezanson, et al… Julia Subtyping: A Rational Reconstruction. Proceedings of the ACM on Programming Languages, 2018, 27, ⟨10.1145/3276483⟩. ⟨hal-01882137⟩

The authors of the above paper re-implemented Julia’s subtype relation, <:. I’d like to try it out, where can I find the source? @fzn @julbinb @ulysses @ckfinite

If sharing the sources is not an option, I’m particularly interested in the following: Vector{<:Int} <: Union{Vector{Int},Vector{Union{}}}.

It seems all the data I want is here (although there’s no Git repo, sadly): Julia Subtyping: a Rational Reconstruction