Compile error: Access String array by subscript

[shoken0x]

This code is compile error on 2nd line.

let strArray = ["s", "w", "i", "f", "t"]
let char = strArray[0]

After comment out below on Array.swift, build succeeded.

/**
*  Same as `at`
*/
subscript (indexes: Int...) -> Array {
    return at(reinterpretCast(indexes))
}