How to assign parameter's type of generic callback in swift?

Question

Suppose I have following function:

func fetch<T: Codable>(completion: @escaping (_ response: SimpleResult<[T]>) -> Void) {
      completion(parse(result))
}

Xcode does not show any error on above function. But how to use it? If I write following, it shows error:

fetch { result in 
}

It says that "Generic parameter T could not be inferred". I suppose that I should indicate type here. But where should I write it?

Answer 1

You need to explicitly state the result type:

fetch { (result: SimpleResult<YOUR_CODABLE_TYPE>) in
}