CircularBuffer error after upgrading to Xcode 13.3, SwiftNIO, Vapor in the mix

Question

I have a project that will not compile, after upgrading to Xcode 13.3 The error is

Type 'CircularBuffer<Element>' does not conform to protocol 'MutableCollection'

and

Unavailable subscript 'subscript(_:)' was used to satisfy a requirement of protocol 'MutableCollection'

This is in the public struct MarkedCircularBuffer<Element>: CustomStringConvertible that is part of SwiftNIO.

This pops up as soon as I try to build the project, which built and ran fine prior to the upgrade to Xcode 13.3.

I don't have a starting point to figure this out. What should I be looking for? My only intuition is that a number of async queries in my code dump the result into a _ rather than a variable, but that seems reasonable given the compiler suggests it…

EDIT: because there is a reference to protocols, I checked my code, and only one protocol is defined (but never implemented):

protocol storesSockets {
//    var sockets: Dictionary<String, Dictionary<String, WebSocket>>
    func addSocket(ws: WebSocket, pId: String, gameId: String, overwrite: Bool)
}

Commenting this code out does not change anything.

UPDATE: I tried updating the packages in Swift... this caused a crash, which restarting Swift didn't fix, but restarting the machine did. Or seems to have. So my problem has gone away...

Answer 1

I ran into the same problem and updated swift-nio to 2.40.0 to solve the problem.

EDIT: Updating caused a crash sometimes (this might be related to the Apple Silicon M1 Mac) but after the crash and the finished update the error was gone.