Comment by Seyed Samad Gholamzadeh (JIRA)

I have this problem too.
I think it's a bug!🙁

Comment by swesthk (JIRA)

Same problem here!!!

Comment by Seyed Samad Gholamzadeh (JIRA)

I think I found the cause of this problem. It seems since Xcode 8 apple don't allow to developers create subclass for UIColor.
this is what apple has written in UIColor api reference:

Subclassing Notes
Most developers have no need to subclass UIColor. The only time doing so might be necessary is if you require support for additional colorspaces or color models. If you do subclass, the properties and methods you add must also be safe to use from multiple threads.

By the way I have written a small extension for UIColor that maybe solves your problem:
Xcode Pencils Colors
With Regard.

Comment by Marc Knaup (JIRA)

The subclassing notes for UIColor aren't new. Apple clearly allows subclassing.

The Objective-C -> Swift import seems to have a bug which imports an extension initializer as required which isn't even allowed in Swift!

extension UIColor {

    @nonobjc required public convenience init(colorLiteralRed red: Float, green: Float, blue: Float, alpha: Float)
}

The only workaround so far seems to be to add only convenience initializers in the subclass or to not add any initializers at all. That way the problematic initializer is inherited automatically.

(Xcode 8.2)

Comment by Martin Straub (JIRA)

This is just annoying...

Tried to get a nice solution using UIColor and Codable. But it's neither possible to add the Codable requirements in an extension, nor using subclasses because of this bug :-/

Comment by Sergey A. Novitsky (JIRA)

I have observed the same for NSString (Xcode 9 and Swift 4).

Xcode offers a fix for the missing required initializer of an extension:

required convenience init(stringLiteral value: StaticString) {

    fatalError("init(stringLiteral🙂 has not been implemented")

}

But it obviously does not compile.

Comment by Vitalii Budnik (JIRA)

Xcode 10.2 (10E125)
Swift: Apple Swift version 5.0 (swiftlang-1001.0.69.5 clang-1001.0.46.3)
macOS: 10.14.4 (18E226)

The problem is still here. The code below doesn't compile.

import Foundation
#if os(iOS)
import UIKit
typealias NSColor = UIColor
#elseif os(macOS)
import AppKit
#endif

internal final class AnotherColorClass: NSColor {
  
  internal init(param: Any) {}
  
  @nonobjc required convenience init(
    _colorLiteralRed red: Float,
    green: Float,
    blue: Float,
    alpha: Float
    )
  {
    fatalError("init(_colorLiteralRed:green:blue:alpha:) has not been implemented")
  }
  
  internal required init?(coder: NSCoder) {
    fatalError("init?(coder:) has not been implemented")
  }
  
  #if os(macOS)
  internal required init?(
    pasteboardPropertyList propertyList: Any,
    ofType type: NSPasteboard.PasteboardType
    )
  {
    fatalError("init?(pasteboardPropertyList:ofType:) has not been implemented")
  }
  #endif
}