Dyno is really freakish and I can see a couple of pain points if someone tries to use it productively. A IMO glaring one is that dyno::poly is a boxing type that will happily take your value type and shove it on the heap while nobody's looking. This is a defect similar to the silent heap allocations for captured parameters in std::function.

On the other hand, it's really impressive that one can push dynamic function pointer lookup tables in C++ to a point where it looks almost, but maybe not quite like the real thing.