[ANN] ManualDispatch.jl

[tisztamo]

@jebej

I thought the whole point of union splitting was to do this automatically, as explained in this blog post: https://julialang.org/blog/2018/08/union-splitting/ . Why is this faster?

Because abstract types can be extended with new subtypes, while unions cannot:

Union splitting over abstract types

If I have an abstract type X whose only subtypes are A and B, will union-splitting kick in and make dispatching over an object inferred as X as efficient as dispatching over one inferred as Union{A, B}?