A test of inferred return types in Swift, both generic and overloaded nillable

nillableReturnTypeTest.swift

import UIKit

class A : CustomDebugStringConvertible
{
    let message: String
    
    required init( message: String ) { self.message = message }
    
    var debugDescription: String { return message }
}
class AA : A {}
class AB : A {}


func test<SomeType:A>() -> SomeType
{
    return SomeType( message: "\(String(SomeType)) created through a non-nillable method invocation" )
}

func test<SomeType:A>() -> SomeType?
{
    return SomeType( message: "\(String(SomeType)) created through a nillable method invocation" )
}

let first  : AA? = test()
let second : AA  = test()
let third  : AB? = test()
let fourth : AB  = test()