Does anybody else miss optional requirements on protocols?

[Joe_Groff]

If you want no compromises on capabilities, but can compromise on verbosity, I'll link to my previous post on this topic:

Optional Protocol Members

There's an idiom I've been playing with to encode conditional capabilities directly into protocol conformances, using uninhabited types. You can have a base protocol capture the type's conformance to a derived protocol in an associated type, which is either constrained to be equal to Self when the type conforms to the derived protocol, or defaults to an uninhabited type such as Never: protocol Base { associatedtype AsDerived: Derived = Never func baseRequirement() } protocol Derived: Bas…