Example of using `weakify` to pass instance functions as one-liners without creating retain cycles.

ContrivedWeakifyExample.swift

@inlinable
public func weakify<Target, each Argument>(
    _ closureProvider: @escaping (Target) -> (repeat each Argument) -> Void,
    on target: Target
) -> (repeat each Argument) -> Void where Target: AnyObject {
    { [weak target] (arguments: repeat each Argument) in
        guard let target else {
            return
        }
        
        closureProvider(target)(repeat each arguments)
    }
}

@inlinable
public func weakify<Target, Output, each Argument>(
    _ closureProvider: @escaping (Target) -> (repeat each Argument) -> Output,
    on target: Target,
    default: @autoclosure @escaping () -> Output
) -> (repeat each Argument) -> Output where Target: AnyObject {
    { [weak target] (arguments: repeat each Argument) in
        guard let target else {
            return `default`()
        }
        
        return closureProvider(target)(repeat each arguments)
    }
}

class MyView: UIView {
    var onTap: ((String) -> Void)?
    
    init() {
        super.init(frame: .zero)
    }
    
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
}

class MyViewController : UIViewController {
    private lazy var myView: MyView = {
        let view = MyView()
        view.onTap = weakify(MyViewController.handleTap, on: self)
        return view
    }()

    private func handleTap(id: String) {
        print("id")
    }
}