Defining classes with cyclic dependencies

[Per Nordlöw]

On Sunday, 17 March 2024 at 20:38:16 UTC, Per Nordlöw wrote:
> I was surprised that the compiler cannot compile
>
> ```d
> class A { B b; }
> class B { C c; }
> class C { D d; }
> class D { A a; }
> ```
>
> . Shouldn't it?

Ahh, nevermind. I defined these inside a unittest scope so that's 
why it failed. Defining them at module scope works just fine.