Slice dereferencing does not work

[cbrom]

package main

type Soo struct {
    sliceI32 []i32
}

func main()() {
    var sliceSoo []Soo

    var soo Soo
    sliceSoo = append(sliceSoo, soo)

    sliceSoo[0].sliceI32 = append(sliceSoo[0].sliceI32, 5)
}