Swift 3 – Resolving method ambiguity defining closures as a var

test1.swift

// objc's continue method signature: - (AWSTask *)continueWithBlock:(AWSContinuationBlock)block;
// swift translate it as: .continue(block: (AWSTask<AWSCognitoIdentityUserPoolSignUpResponse>) -> Any?)

// error: Ambiguous use of 'continue'
pool.signUp(username,
  password: password,
  userAttributes: attrs,
  validationData: nil)
  .continue { (task) -> Any? in
}

// typealias to the rescue…

typealias SignUpContinueClosure = (AWSTask<AWSCognitoIdentityUserPoolSignUpResponse>) -> (Any?)

var signUpContinueClosure: SignUpContinueClosure = { (task) in
  return nil
}

// YAY!, no error!
pool.signUp(username,
  password: password,
  userAttributes: attrs,
  validationData: nil)
  .continue(signUpContinueClosure)