duplicates:

• SR-416 Automatic initializer inheritance doesn't work for generic types.

Issue Description:

According to Apple's documentation Swift does not necessary require override of initializer. In a following code example Bar inherits initializer of Foo:

class Foo {
  let value: Int
  init(value: Int = 5) {
    self.value = value
  }
}

class Bar: Foo {
}

Modifying code as below prevents inheritance of initializer.

class Foo<T> {
  let value: Int
  init(value: Int = 5) {
    self.value = value
  }
}

class Bar: Foo {
}

Here are an option how to define a class with generic that does not require override of designated initializer:

protocol FooProtocol {
    associatedtype T
}

class Foo<U>: FooProtocol {
    typealias T = U

    let value: Int
    init(value: Int, otherValue: T) {
        self.value = value
        self.otherValue = otherValue
    }
}

class Bar: Foo<Int> {
}

However there is another interesting observation of behavior. Defining initializer like following cause override requirement:

init(value: Int = 5) {
    self.value = value
}

The funny thing thing that adding one more parameter as following into such designated initializer cause this override requirement to disappear:

init(value: Int = 5, otherValue: T) {
    self.value = value
}