id: string-concat-in-loop
valid:
  - |
    var sb strings.Builder
    for _, x := range items {
        sb.WriteString(strconv.Itoa(x))
    }
    s := sb.String()
  - |
    s := "fixed value"
invalid:
  - |
    var s string
    for _, x := range items {
        s += strconv.Itoa(x)
    }
  - |
    for _, x := range items {
        s += strconv.Itoa(x)
    }