P.bar ですね。現状では P.bar はそもそも使えない (Static member 'bar' cannot be used on protocol metatype 'P.Protocol') けどそれが使えるようになって、さらにコンテクストタイプが : P の時に implicit member expression で参照できる(edited)
Swift's dot shorthand for static factories is wonderful! Unfortunately, it currently requires a concrete type context in order to work. A while ago I pitched an idea for lifting this limitation. It turned out that the original idea in that pitch isn't viable, but the thread ...
