Why does Swift playground shows wrong number of executions?

Question

I am using a completion handler to sum up numbers. What I don't understand is if I break my code in 2 lines, the number of executions would change from 6 to 7!! WHY?

 func summer (from : Int, to: Int, handler: (Int) -> (Int)) -> Int {
        var sum = 0
        for i in from...to {
            sum += handler(i)
        }
        return sum

}

summer(1, to:6){ //Shows '21'
    return $0} // shows '(6 times)'


// Same code, but in 1 line
summer(1, to:6){return $0} // shows '(7 times)'

IMAGE

Answer 1

It's showing how many times a function / expression is being called on that line:

since the calling expression (summer()) is on the same line, it counts as an extra operation. Hence, 6 prints + 6 returns + 1 summer() = 13 times something happened on that line.

I'm not sure if I used the correct terminology, but this is what's going on.

Answer 2

It's merely a consequence of the presentation:

21 //the result from the first time
(6 times) //the other 6 times

(7times) //all 7 times, including the 21 one.