In previous versions of Xcode 6 and 7 with Swift, this syntax would work:
    var secureItemValue: Unmanaged<AnyObject>?
    let statusCode: OSStatus = SecItemCopyMatching(keychainItemQuery, &secureItemValue)
    if statusCode == errSecSuccess
    {
        let opaquePointer = secureItemValue?.toOpaque()
        let secureItemValueData = Unmanaged<NSData>.fromOpaque(opaquePointer!).takeUnretainedValue()
        // Use secureItemValueData...
    }
However, the SecItemCopyMatching declaration has changed in Xcode 7 beta 4:
OLD:  func SecItemCopyMatching(_ query: CFDictionary, _ result: UnsafeMutablePointer<AnyObject?>) -> OSStatus
NEW:   func SecItemCopyMatching(_ query: CFDictionary!, _ result: UnsafeMutablePointer<Unmanaged<AnyObject>?>) -> OSStatus
...and now the secureItemValue type does not match.
The mechanism was confusing before to extract the result, and I'm hoping it is somehow easier with the new declaration, but I don't know how to declare the correct type for the secureItemValue variable and extract the result.
 
                        
This works on Xcode 7 beta 4