Cannot invoke 'indexOf' with an argument list of type '(ChecklistItem)'

Question

When I am writing code for finding an item from the array with the use of indexOf it shows me the above stated error. Here is my code:-

func addItemViewContr         


        

Answer 1

I realize this question already has an accepted answer, but I found another case that will cause this error so it might help someone else. I'm using Swift 3.

If you create a collection and allow the type to be inferred you may also see this error.

Example:

// UITextfield conforms to the 'Equatable' protocol, but if you create an
// array of UITextfields and leave the explicit type off you will
// also see this error when trying to find the index as below
let fields = [
        tf_username,
        tf_email,
        tf_firstname,
        tf_lastname,
        tf_password,
        tf_password2
    ]

// you will see the error here
let index = fields.index(of: textField)

// to fix this issue update your array declaration with an explicit type
let fields:[UITextField] = [
    // fields here
]