@OlegYch's solution also represents a good trade off of complexity vs. convenience: his solution is simpler but doesn't get along so nicely with type inference;

@OlegYch's solution also represents a good trade off of complexity vs. convenience: his solution is simpler but doesn't get along so nicely with type inference; mine gets on just fine with type inference, but is more complex and depends (no pun intended) on dependent method types. As ever YMMV.