Allowing @unknown in arbitrarily nested patterns

[xwu (Xiaodi Wu)]

@masters3d

Can you provide some references to this? We should probably have a guidance document with theses group held notions that can help guide design authors.

I believe this term first emerged during discussion of SE-0286:

[Pitch #2] Forward scan matching for trailing closures

I think we can agree that this pitch is a better "resting" place than the one we have right now. IIUC, your desire is to get this change in before Swift 5.3 ships, right? I would support that. We can discuss the longer term changes when there is more time.

SE-0286: Forward Scan for Trailing Closures

This proposal needs to put us at a good "resting place" both for Swift 5.3+ and Swift 6. The heuristic makes the forward scan work for enough existing APIs that I don't feel like we can simply drop it from Swift 6 without a suitable replacement. For example, I call out this SwiftUI example in the proposal: func sheet( isPresented: Binding<Bool>, onDismiss: (() -> Void)? = nil, content: @escaping () -> Content ) -> some View The intent here is clear: the unlabeled trailing closure is sup…