Implicit arguments: how to encode in function signature?

Question

Following the awesomely enlightening question by @TravisBrown concerning the enumeration of ADTs using shapeless, I am left with the following code snippet:

impl         


        

Answer 1

If you look at the definition of implicitly[X], you can see that is requires an implicit argument of type X in scope. In your example, you have implicit ev: T in scope, which is not enough to call implicitly[EnumerableAdt[T]]! Try the following definition instead:

def imply[T](implicit ev: EnumerableAdt[T]):Set[T] = ev.values