self is no longer required in many places

Paul Hudson      @twostraws

SE-0269 allows us to stop using self in many places where it isn’t necessary. Prior to this change, we’d need to write self. in any closure that referenced self so we were making our capture semantics explicit, however often it was the case that our closure could not result in a reference cycle, meaning that the self was just clutter.

For example, before this change we would write code like this:

struct OldContentView: View {
    var body: some View {
        List(1..<5) { number in
            self.cell(for: number)
        }
    }

    func cell(for number: Int) -> some View {
        Text("Cell \(number)")
    }
}

That call to self.cell(for:) cannot cause a reference cycle, because it’s being used inside a struct. Thanks to SE-0269, we can now write the same code like this:

struct NewContentView: View {
    var body: some View {
        List(1..<5) { number in
            cell(for: number)
        }
    }

    func cell(for number: Int) -> some View {
        Text("Cell \(number)")
    }
}

This is likely to be extremely popular in any framework that makes heavy use of closures, including SwiftUI and Combine.

Other changes in Swift 5.3…

• Multi-pattern catch clauses
• Multiple trailing closures
• Synthesized Comparable conformance for enums
• Type-based program entry points
• where clauses on contextually generic declarations
• Enum cases as protocol witnesses
• Refined didSet semantics
• A new Float16 type
• Swift Package Manager gains binary dependencies, resources, and more

Download all Swift 5.3 changes as a playground Link to Swift 5.3 changes

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