Type checker doesn't infer generics properly

class Test {
    static test2() {
        if (new Random().nextBoolean()) {
            def a = new ArrayList<String>()
            a << "a" << "b" << "c"
            return a
        } else {
            def b = new LinkedList<Number>()
            b << 1 << 2 << 3
            return b
        }
    }

    static test() {
        def result = test2()
        result[0].toInteger()
        //result[0].toString()
    }
}
new Test()