Example: Automatic initializer inheritance doesn't work for generic types.

GenericNode.swift

class Node<T> {
    let value: T

    init(value: T) {
        self.value = value
    }
}

class Terminal<T>: Node<T> {
}

// OK
let node = Node(value: "node")

// error: 'Terminal<T>' cannot be constructed because it has no accessible initializers
let terminal = Terminal(value: "terminal")

OverrideNode.swift

class Node<T> {
    let value: T

    init(value: T) {
        self.value = value
    }
}

class Terminal<T>: Node<T> {
    override init(value: T) {
        super.init(value: value)
    }
}

// OK
let node = Node(value: "node")

// OK
let terminal = Terminal(value: "terminal")

StringNode.swift

class Node {
    let value: String

    init(value: String) {
        self.value = value
    }
}

class Terminal: Node {
}

// OK
let node = Node(value: "node")

// OK
let terminal = Terminal(value: "terminal")

[SR-416] Automatic initializer inheritance doesn't work for generic types. - Swift

Automatic initializer inheritance

...

Rule 1

If your subclass doesn’t define any designated initializers,
it automatically inherits all of its superclass designated initializer.

Rule 2

If your subclass provides an implementation of all of its superclass designated initializers—either
by inheriting them as per rule 1,
or by providing a custom implementation as part of its definition—then
it automatically inherits all of the superclass convenience initializers.

Automatic Initializer Inheritance - The Swift Programming Language