Yes, C# and lots of other language have that feature. Where it gets really tricky is if you want to dynamically check the type of functions or objects, since yo

Yes, C# and lots of other language have that feature. Where it gets really tricky is if you want to dynamically check the type of functions or objects, since you need to run the assertions when the function/method gets called rather than when the function/method gets assigned to some reference. Its also tricky to give a parametric type to code that is implemented with dynamic types.