This is Nate's idea, something I use on every project. Sometimes you need to accommodate an optional that shouldn't be optional.

AssertUnwrap.swift

public extension Optional {

    /// Stop in the debugger in debug builds if self is `.none`.
    ///
    /// Example usage:
    ///
    ///   guard let value = maybeValue.assertUnwrap() else { return "bogus value" }
    ///
    func assertUnwrap(_ message: @autoclosure () -> String? = nil, file: StaticString = #file, function: String = #function, line: UInt = #line) -> Wrapped? {
        switch self {
        case .some(let wrapped):
            return wrapped
        case .none:
            // If this is a DEBUG build, stop in the debugger. Otherwise, return nil.
            // Alternatively you can call assertionFailure(), but this allows execution to continue.
            #if DEBUG
            printToLog(msg, file: file, function: function, line: line)
            raise(SIGINT)
            #endif
            return nil
        }
    }

}