protocol PossibleResultType {}

protocol A {
    associatedtype ResultType: PossibleResultType
}

protocol B: A {
    // This code sample fails to compile. Uncommenting the redundant associatedtype declaration below causes compilation to succeed.
    // A warning occurs on this associatedtype declaration, for good reason. But, performing the warning's fit-it results in a build failure in Implementer and an additional warning in the declaration of B. This declaration should not be necessary, as ResultType is declared in A.
    //associatedtype ResultType: PossibleResultType
    func anotherResult() -> ResultType
}

extension String: PossibleResultType {}
struct Implementer: B {
    func anotherResult() -> String { return "foo" }
}