Nil coalescing operator has very low precedence and it's very easy to forget the parentheses. It's tempting to write something like this:
let result = v1 ?? 0 + v2 ?? 0 Which will resolve to let result = v1 ?? (0 + v2 ?? 0) An example of incorrect code from real project which went unnoticed for some time: let allParameters: [String: Any?] = defaultParameters["sendMessage"] ?? [:] + parameters + ["chat_id": chat_id, "text": text] Unlike ternary operator I can hardly think of a case when someone would want to use ?? in expression like: a + b ?? c + d meaning (a + b) ?? (c + d) This seems to be a source of errors in other languages as well, for example: http://www.codeproject.com/Tips/721145/Beware-The-null-coalescing-operator-is-low-in-the I propose to consider raising it's precedence or requiring parentheses if ?? is used with multiple statements. -- Andrey Fidrya _______________________________________________ swift-evolution mailing list swift-evolution@swift.org https://lists.swift.org/mailman/listinfo/swift-evolution
