Get the type name of derived type in a static method of base class or extension Swift

问题

TL:DR Paste this into Swift playground:

import UIKit

public protocol NibLoadable {
    static var nibName: String { get }
}

extension NibLoadable where Self: UIView {
    public static var nibName: String {
        return String(describing: self)
    }

    func printName(){
        print(Self.nibName)
    }
}

public class Shoes: UIView, NibLoadable {


    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
        printName()
    }

    override init(frame: CGRect) {
        super.init(frame: frame)
        printName()
    }
}

public class Cake: Shoes {

}

let cake = Cake() // this line prints 'Shoes'

How do i make it print Cake, not Shoes?

Full explanation:

I have found the method to get xib files loaded into storyboards like so: https://stackoverflow.com/a/47295926/2057955

This works amazingly, however i have to put boilerplate NibLoadable code into each view like so:

required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
        setupFromNib()
    }

    override init(frame: CGRect) {
        super.init(frame: frame)
        setupFromNib()
    }

this is obviously pretty annoying when you have some 20-30 views in this manner.

So i am trying to setup a base class that would take care of this, and then have everything inherit it.

Unfortunately and no matter what i tried, the String(describing: Self.self) always returns the name of my base class, NOT the name of the derived class.

I get this exception in the console logs when i open my Storyboard in XCode:

[MT] IBSceneUpdate: [scene update, delegate=] Error Domain=IBMessageChannelErrorDomain Code=3 "Failed to communicate with helper tool" UserInfo={NSLocalizedFailureReason=The agent raised a "NSInternalInconsistencyException" exception: Could not load NIB in bundle: 'NSBundle (loaded)' with name 'BaseNibLoadable.Type', IBMessageSendChannelException=Could not load NIB in bundle: 'NSBundle (loaded)' with name 'BaseNibLoadable.Type', NSLocalizedDescription=Failed to communicate with helper tool}

Example:

@IBDesignable
class BaseNibLoadable: UIView, NibLoadable {
    // MARK: - NibLoadable
    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
        setupFromNib()
    }

    override init(frame: CGRect) {
        super.init(frame: frame)
        setupFromNib()
    }
}

@IBDesignable
class SomeHeader: BaseNibLoadable {

    @IBOutlet fileprivate weak var headerLabel: UILabel!
    @IBInspectable var header: String? {
        didSet {
            self.headerLabel.text = header
        }
    }
}

Obviously my main bundle (same bundle for both) includes the SomeHeader.xib file.

So what i am looking for is to somehow get the name of the actual type being instantiated in the nibName static method.

UPDATE As requested, here is the original answer i linked at the top of the question (rather, just the code from it as it is quite long otherwise... please follow the link):

public protocol NibLoadable {
    static var nibName: String { get }
}

public extension NibLoadable where Self: UIView {

    public static var nibName: String {
        return String(describing: Self.self) // defaults to the name of the class implementing this protocol.
    }

    public static var nib: UINib {
        let bundle = Bundle(for: Self.self)
        return UINib(nibName: Self.nibName, bundle: bundle)
    }

    func setupFromNib() {
        guard let view = Self.nib.instantiate(withOwner: self, options: nil).first as? UIView else { fatalError("Error loading \(self) from nib") }
        addSubview(view)
        view.translatesAutoresizingMaskIntoConstraints = false
        view.leadingAnchor.constraint(equalTo: self.safeAreaLayoutGuide.leadingAnchor, constant: 0).isActive = true
        view.topAnchor.constraint(equalTo: self.safeAreaLayoutGuide.topAnchor, constant: 0).isActive = true
        view.trailingAnchor.constraint(equalTo: self.safeAreaLayoutGuide.trailingAnchor, constant: 0).isActive = true
        view.bottomAnchor.constraint(equalTo: self.safeAreaLayoutGuide.bottomAnchor, constant: 0).isActive = true
    }
}

Update 2

I do know that the subclass is definitely in the stack at that point because if i log the Thread.callStackSymbols the actual concrete view class name is there.