struct CalendarView {
    private let months: [[String]] = [["jan.", "feb.", "mar.", "apr."]]
    private func makeMonthPill() {}
    
    func foo() {
        GorEach(months) { group in
            GorEach(group) { month in
                self.makeMonthPill()
            }
        }
    }
}

struct Binding<T> {}

protocol View2 {}

@resultBuilder struct ViewBuilder2 {
  static func buildBlock<Content>(_ content: Content) -> Content where Content : View2 { fatalError() }
}

struct GorEach<Data, Content> where Data : RandomAccessCollection {
    init<C>(_ data: Binding<C>, @ViewBuilder2 content: (Binding<C.Element>) -> Content) where C : MutableCollection {}
    init(_ data: Data, @ViewBuilder2 content: @escaping (Data.Element) -> Content) {}
}