Ah, I misunderstood the question. Yes, in that case it's fairly type-safe.
> The actual reflection going on in the code I posted for multiple dispatch would surely be nothing more than an int comparison
Is this based on gut reaction or are you talking about optimizations that `dynamic` performs? I ask because my understanding is that `dynamic` is like a really efficient reflection-emitter, that attempts to do at runtime the same thing that the compiler would do at compile time, but slower because it has to look stuff up via reflection.
From Eric Lippert [2]:
> The magic is: the compiler emits code that starts the C# compiler again at runtime. The runtime version of the compiler analyzes the call as though the compile-time types of all the objects had been their actual runtime types, generates an expression tree representing that call, compiles the expression tree, caches the delegate for next time, and runs the delegate.
[2]: http://stackoverflow.com/questions/10330805/c-sharp-multiple...
So maybe `dynamic` at runtime figures out that it can do a "a struct with an int tag to represent the type, and a void pointer for its value", but I wouldn't assume it does and from what I've read on it, I wouldn't think that it does.
