重载解析度模糊:公共最终运算符fun inc()

I have error building with kotlin when i use method inc()

我的片段代码如下

var id : Int = 1
        for (element in iframeElements) {
            val src: String = element.attr("src")
            Timber.d("YOUTUBE LINK: %s", src)
            if (src.contains("youtube")) { // i.e https://www.youtube.com/embed/16Sn1UQ95Ec
                val idYoutube = src.substring(src.lastIndexOf('/') + 1, src.length)
                val videoInfo = YoutubeVideo()
                videoInfo.setVideoId(idYoutube)
                videoInfo.setId(id as Long)
                videoInfo.setImageUrl(getUrlforYoutubeThumbnail(idYoutube))
                lsYoutube.add(videoInfo)
                id = id.inc() // THIS PART ERROR
            } else if (src.contains("instagram")) { // i.e https://www.instagram.com/p/Bs421mHgPM4/embed
//String ig = src.substring(0, src.lastIndexOf('/'));F
                Timber.d("ig %s", src)
                lsInstagramUrl.add(src)
            }
        }

enter image description here

我真的很困惑我应该修复哪一部分?或如何使用Kotlin设定增量编号(Integer)。我的代码不正确吗?