[Groxx]

"it exists as a niche feature that few use and fewer understand" isn't exactly "mainstream" IMO (it's significantly less common from what I've seen than manual classloader shenanigans, for example). But yes, it's nice that it exists, and I wish it were used more - it'd catch low-effort stuff like this one was.

[darthwalsh]

No, C# had it: past tense. CAS was neutered in .NET Framework 4.0 then removed in dotnet core.

[Groxx]

alas. don't suppose you know of any good articles on why it's removed? I'd be curious about the reasoning / challenges.

there are some rather obvious challenges, but a huge amount of the ones I've run across end up looking mostly like "it's hard to add to an existing language" which is extremely understandable, but hardly a blocker for new ones.

[int_19h]

I don't know if there were any articles specifically detailing it, but from blog posts at the time the clear message was that they didn't consider the intended security guarantees to be possible to uphold in practice, so much so that "CAS and appdomains shouldn't be considered a security boundary".