Playing around casting of generic protocol

GenericCasting.swift

protocol AnyProtocol {
    func checkAndRemove<T>(_ predicate: (T) -> Bool) -> Bool
    func checkAndRemove<T>() -> T?
    func insert<T>(_ value: T)
}

protocol ProtocolA: AnyProtocol {
    associatedtype T

    var size: Int { get }
    func insert(value: T)
    func remove() -> T
}

extension ProtocolA {
    func checkAndRemove<T>(_ predicate: (T) -> Bool) -> Bool {
        if size > 0, let removed = remove() as? T, predicate(removed) {
            return true
        }

        return false
    }

    func checkAndRemove<T>() -> T? {
        if size > 0 {
            return remove() as? T
        }

        return nil
    }

    func insert<T>(_ value: T) {
        if let value = value as? Self.T {
            insert(value: value)
        }
    }
}

class ClassA<T: Comparable>: ProtocolA {
    private var array = [T]()
    var size: Int {
        array.count
    }

    func insert(value: T) {
        array.append(value)
        array.sort()
    }

    func remove() -> T {
        array.removeFirst()
    }
}

let objArray: [AnyProtocol] = [ClassA<Int>()]
objArray.first?.insert(42)
objArray.first?.insert(0)
objArray.forEach({ obj in
    if obj.checkAndRemove({ $0 == 0 }) {
        print("removed 0")
    }
})
let removed: Int? = objArray.first?.checkAndRemove()
print(removed ?? "nothing")