AsAny.swift

// Discussion: https://twitter.com/an0/status/644176341986856960

["a": "a"] as? [String: Any] // warning: conditional cast from '[String : Any]' to '[String : Any]' always succeeds

let a: Any = ["a": "a"]
let b = a as? [String: String]
let c = a as? [String: AnyObject]
let d = a as? [String: Any]

if let b = b {
    let e = b as? [String: Any] // error: '[String : String]' is not convertible to '[String : Any]'
}
if let c = c {
    let f = c as? [String: Any] // error: '[String : AnyObject]' is not convertible to '[String : Any]'
}