>Hmm, I think you could do something similar to QuickCheck using C# generics

You can't do this. Quick check can generate type classes instances, for example, for tuples, functions, etc. This is impossible in language like C#.

There are certainly cases which aren't expressible(things which require kinding, for example) but your examples aren't a problem. Both tuples and functions can be represented using System F, and thus can be completely transposed into C# generics.

I believe you don't understand C# generics and you should look closer at the fundamental type calculus.

No it's not. The feature C# calls reflection lets you inspect types and generate them automatically.

If we use reflection, we might know about error only in runtime. What haskell does is guaranteed to work at compile time. That's why it's so cool.

QuickCheck doesn't do anything interesting at compile time.

"What haskell does is guaranteed at compile time to work."