struct R<V,Error> {}
struct Rsp<C> {}
protocol P {
    typealias PR<C> = R<Rsp<C>,Error>
    typealias AnyPR = PR<Any>
}
func f1<Value> (
    cl1: (R<Value,Error>) -> Void
){}
func f2 (
    cl2: (P.AnyPR) -> Void
){}
func f3<Value> (
    cl1: (R<Value,Error>) -> Void,
    cl2: (P.AnyPR) -> Void
){}


func callFs(
    cl1: (R<Void,Error>) -> Void,
    cl2: (P.AnyPR) -> Void
)
{
    f1(cl1: cl1) // Compiles
    f2(cl2: cl2) // Compiles

    // Since the calls to f1 & f2 compile, a call to f3 should also compile
    // First concern:  Xcode 10.2 provides the following (incorrect?)
    // completion for invoking "f3"
    // f3(cl1: <#T##(R<P, Error>) -> Void#>, cl2: <#T##(R<Rsp<Any>, Error>) -> Void#>)
    // And when I pass in the arguments to f3 the way I did to f1 & f2,
    // I get a compiler error
    f3(
        cl1: cl1, // Error: In argument type '(R<Void, Error>) -> Void', '()' does not conform to expected type 'P'
        cl2: cl2
    )
}