Circular enum member references in UDAs

[Paul Backus]

On Thursday, 15 February 2024 at 18:12:42 UTC, realhet wrote:
> Hello,
>
> Today I tried to upgrade my sources to the latest LDC, but 
> failed with this unfortunate error.
>
> ```
> import std;
>
> struct S{ E e; }
>
> enum E
> {
>     @S(e2) e1,
>     @S(e1) e2
> }
> ```

Looks like someone reported a similar bug in 2018:

https://issues.dlang.org/show_bug.cgi?id=17656

There was an attempt to fix it, but it looks like the PR author 
wasn't able to get it working correctly in all cases.