$ swift -I.build/debug -L.build/debug -lResult                              
Welcome to Swift version 3.0.2 (swift-3.0.2-RELEASE). Type :help for assistance.
  1> import Foundation
  2> import Result
  3> let r = Result<String, AnyError>("a")
r: Result.Result<String, Result.AnyError> = success {
  success = "a"
}

[...]

  8> let nse = NSError(domain: "Foo", code: 42, userInfo: [NSLocalizedDescriptionKey: "localized description"]) 
nse: Foundation.NSError = {
  Foundation.NSObject = {}
  _domain = "Foo"
  _code = 42
  _userInfo = 1 key/value pair {
    [0] = {
      key = "NSLocalizedDescription"
      value = "localized description"
    }
  }
}
  9> print(nse.localizedDescription)
localized description
 10> print(nse.userInfo[NSLocalizedDescriptionKey])
Optional("localized description")
 11> let ae = AnyError(nse)
ae: Result.AnyError = {
  error = <extracting data from value failed>

}
Execution interrupted. Enter code to recover and continue.
Enter LLDB commands to investigate (type :help for assistance.)
 12> :bt
* thread #&#8203;1: tid = 1401, 0x00007ffff7cde9cf libswiftCore.so`_dynamicCastFromExistential(swift::OpaqueValue*, swift::OpaqueValue*, swift::TargetExistentialTypeMetadata<swift::InProcess> const*, swift::TargetMetadata<swift::InProcess> const*, swift::DynamicCastFlags) + 191, name = 'repl_swift', stop reason = signal SIGSEGV: invalid address (fault address: 0x0)
  * frame #&#8203;0: 0x00007ffff7cde9cf libswiftCore.so`_dynamicCastFromExistential(swift::OpaqueValue*, swift::OpaqueValue*, swift::TargetExistentialTypeMetadata<swift::InProcess> const*, swift::TargetMetadata<swift::InProcess> const*, swift::DynamicCastFlags) + 191
    frame #&#8203;1: 0x00007ffff7cde49b libswiftCore.so`swift_dynamicCast + 955
    frame #&#8203;2: 0x00007ffff7f582fb libResult.so`AnyError.init(error=Error @ 0x00007fffffffe500, self=Result.AnyError @ 0x00007fffffffe508) -> AnyError + 91 at Result.swift:197
    frame #&#8203;3: 0x00007ffff7f49e4d $__lldb_expr24`main + 109
    frame #&#8203;4: 0x00000000004009f0 repl_swift`swift_once + 16
    frame #&#8203;5: 0x00007fffffffe550
    frame #&#8203;6: 0x00007ffff6dd6830 libc.so.6`__libc_start_main + 240
    frame #&#8203;7: 0x0000000000400a19 repl_swift`_start + 41
 12>