Swift 5. Let first child class access a property, but not child of child class-CodePudding

Is it possible to prevent all children of a child class from accessing a variable in a base class in Swift 5? Please no round-about Protocol solutions.

class A { var a:String = ""}
class B : A {protected var a = ""}
class C : B 
{
   func use_a() 
   {
     a = //compiler should complain here that 'a' is protected and cannot be modified
   }
}

CodePudding user response：

It is possible, but only by scoping members using file structure.

File 1:

class A {
  fileprivate var a = ""
}

class B: A {
  fileprivate override var a: String {
    willSet { }
  }
}

File 2:

class C: B {
  var a = 867_5309

  func use_a() {
    super.a // 'a' is inaccessible due to 'fileprivate' protection level
  }
}