is duplicated by:

• SR-6474 Conditional conformance to refined protocol inappropriately fails

Issue Description:

protocol P {
    func test()
}

protocol P2: P {
}

extension Int : P {
    func test() {
    }
}

extension Array : P2 where Element : P {
    func test() {
    }
}

The compiler said “Type Array<Element> does not conform to protocol P.”

But you can see that `Array` conforms to `P2` which is inherited by `P`

It will be fine if I change `extension Array : P2` to `extension Array: P`.