The Don Syme article (first link) mentions "the critical nature of the interaction that app domains pose to generics". What interaction is that, and what is critical about its nature?
I did a quick search in AppDomain.cpp [0] for 'generic' and there's quite a few comments/variables that mention it. Maybe this [1] is one of the tricky interactions?
[0]: https://github.com/dotnet/coreclr/blob/master/src/vm/appdoma... [1]: https://github.com/dotnet/coreclr/blob/master/src/vm/appdoma...
So without asking Don Syme himself we can only guess.
> I'm not sure if fullblown .Net CLR implementation was released yet
No and AFAIK they don't plan to. There's 'Reference Source' [0], but that's the Base class libraries only, not the CLR itself.
[0]: referencesource.microsoft.com