find.swift

import Foundation
class BaseClass {}

class A : BaseClass {
    
}

class B : BaseClass {
    
}

var refA : A? = A()
var refB : B? = B()

var refArray = [BaseClass?]()
refArray.append(refA)
refArray.append(refB)

func findMatch<T:BaseClass>( in array:[BaseClass?]) -> T? {
    let element = array.first { element in
        element is T
    }
    return element as? T
}

var someRefA: A?

someRefA = findMatch(in: refArray)

print(someRefA)

wrappedType.swift

import Foundation
class BaseClass {}

class A : BaseClass {
    
}

class B : BaseClass {
    
}

protocol OptionalProtocol {
    // the metatype value for the wrapped type.
    var wrappedType: Any.Type { get }
}

extension Optional : OptionalProtocol {
    var wrappedType: Any.Type { return Wrapped.self
    }
}

var refA : A?
var refB : B?

var refArray = [BaseClass?]()
refArray.append(refA)
refArray.append(refB)


for aThing in refArray {
    print(aThing.wrappedType)
}