I don't understand how to do self-referencial parametric typing

[abraemer]

@HenriDeh

You can do self-referencial types if they are non-parametric (Constructors · The Julia Language) but I can’t figure it out for parametric types.

But if it’s impossible then I’ll find another way.

This is indeed not possible:

Mutually recursive type

struct A b::B end struct B a::A end how to do this?

There are workarounds (e.g. abstract types and mutable structs) which you probably won’t like even though they are likely cheap from a runtime perspective.