I believe C# does it at runtime for reference types, and compile time for value types, so that you don't eat the cost of boxing at runtime. It doesn't make sen

I believe C# does it at runtime for reference types, and compile time for value types, so that you don't eat the cost of boxing at runtime. It doesn't make sense to make separate compile time generic types for reference types in C# since the type is basically constrained to using system.object members anyway (unless you add type constraints to the generic type class definition).