Microsoft Edge: Chakra: Type confusion in JavascriptArray::ConcatArgs(CVE-2017-8634)

Let's assume that the following method is called with "firstPromotedItemIsSpreadable = true", and "args" has two elements an array and an integer 0x1234 sequentially. In the first loop, "aItem" is an array, and "firstPromotedItemIsSpreadable" remains true because the condition for the fast path i...