ObjectAbuse.swift

import Darwin

struct S {
    var whatever: AnyObject? = nil
    
    mutating func stuff() {
        withUnsafePointer(&whatever, {
            for offset in 0.stride(to: 128, by: sizeof(AnyObject.self)) {
                let ptr = UnsafePointer<UInt8>($0) - offset
                if malloc_size(ptr) > 0 {
                    print(ptr)
                    let obj = unsafeBitCast(ptr, AnyObject.self)
                    print("I'm in an object of type \(obj.dynamicType)")
                    break
                }
            }
        })
    }
}

class C {
    var a = 42
    var b = 1.1
    var s = S()
}

let c = C()
c.s.stuff()