Typed Throws in Closures

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typed-throws

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enum E: Error {
    case bad
}

func b() throws(E) -> Int {
    throw E.bad
}

func requirement(_: Result<Int, E>) {}

let r = Result { try b() }
requirement(r)

Hint

b() has typed throws (throws(E)), so its thrown errors are statically known to be E. What does the closure in Result.init(catching:) infer for its Failure parameter?

Your answer