Swift2からコンバートしたSwift3のNSAttributedStringでunrecognized selector例外が発生します。

let attributedOptions : [String: AnyObject] = [
    NSDocumentTypeDocumentAttribute: NSHTMLTextDocumentType as AnyObject,
    NSCharacterEncodingDocumentAttribute: String.Encoding.utf8 as AnyObject
]
attributedString = try NSAttributedString(data: encodedData, options: attributedOptions, documentAttributes: nil)


String.Encoding.utf8だとダメで、String.Encoding.utf8.rawValueにする必要があるようです。

let attributedOptions : [String: AnyObject] = [
    NSDocumentTypeDocumentAttribute: NSHTMLTextDocumentType as AnyObject,
    NSCharacterEncodingDocumentAttribute: String.Encoding.utf8.rawValue as AnyObject
]
attributedString = try NSAttributedString(data: encodedData, options: attributedOptions, documentAttributes: nil)


参考:Swift-3 error: '-[_SwiftValue unsignedIntegerValue]: unrecognized selector