Xcode 8.2 Swift Compiler Error: "Segmentation Error: 11"

Question

This function works correctly when I do not implement it in the general case (only using ints), but when I go to make it general, changing only a few letters without obvious errors, Swift cannot compile it; I don’t even use func, just when the file in my project resets it.

Xcode says that "an internal error has occurred." I checked the stack trace and the error is listed as "Segmentation Error: 11." I will post my code below.

I can also send a stack trace on request.

import Foundation

func BinSearch<T : Comparable>(elements: [T], target: T) -> Int?{
    let maxIndex = elements.count - 1
    var rightIndex = maxIndex
    var leftIndex = 0
    var middleIndex : Int {return lround(Double((rightIndex + leftIndex)) / 2)}

    var maxVal : T {return elements[rightIndex]}
    var middleVal : T {return elements[middleIndex]}
    var minVal : T {return elements[leftIndex]}

    while elements[middleIndex] != target {
        //test if in infinite loop for target within range of array but DNE
        if leftIndex == middleIndex || rightIndex == middleIndex && rightIndex != 1{
            return nil
        }

        //prevent infinite loop due to rounding method
        if rightIndex == 1 {
            return leftIndex
        }

        //core code
        if target > middleVal {
            leftIndex = middleIndex
        }else {
            rightIndex = middleIndex
        }
    }
    return middleIndex
}

Answer 1

, , "" , .

, middleVal .

    //core code
    if target > middleVal {
        leftIndex = middleIndex
    }else {
        rightIndex = middleIndex
    }

    //core code
    if target > elements[middleIndex] {
        leftIndex = middleIndex
    }else {
        rightIndex = middleIndex
    }

. .

 BinSearch(elements: [3, 4, 5], target: 2)

0 nil. ( middleIndex middleVal. maxVal minVal .)

( http://rosettacode.org/wiki/Binary_search#Swift):

func binarySearch<T : Comparable>(elements: [T], target: T) -> Int? {
    var leftIndex = 0
    var rightIndex = elements.count - 1

    while leftIndex <= rightIndex {
        let middleIndex = (leftIndex + rightIndex) / 2
        if elements[middleIndex] < target {
            leftIndex = middleIndex + 1 // Continue search in upper half.
        } else if target < elements[middleIndex] {
            rightIndex = middleIndex - 1 // Continue search in lower half.
        } else {
            return middleIndex // Found.
        }
    }
    return nil // Not found.
}

Answer 2

typealias Swift 2 Swift 3, :

(Void -> Void) (() -> ())