DictionaryをDumpしたい2

こちらの続きです。
DictionaryをDumpしたい１ - C#ATIA
タイトルは"Dictionary"が入ってますが、今回は"Collection”です。

調べたところ、キー付きのCollectionは、キーを列挙する方法が
無いんですね。と言う事で、Collectionもダンプさせるように
変更しました。

''' @param x As Variant
''' @return As String
Function Dump( _
        ByVal x As Variant) As String

    Dim ty As String: ty = TypeName(x)
    Select Case ty
        Case "Boolean":     Dump = x
        Case "Integer":     Dump = x & "%"
        Case "Long":        Dump = x & "&"
        #If Win64 Then
        Case "LongLong":    Dump = x & "^"
        #End If
        Case "Single":      Dump = x & "!"
        Case "Double":      Dump = x & "#"
        Case "Currency":    Dump = x & "@"
        Case "Byte":        Dump = "CByte(" & x & ")"
        Case "Decimal":     Dump = "CDec(" & x & ")"
        Case "Date":
            Dim d As String, t As String
            If Abs(x) >= 1 Then d = Month(x) & "/" & Day(x) & "/" & Year(x)
            If Not IsInt(x) Then t = Format(x, "h:nn:ss AM/PM")
            Dump = "#" & Trim(d & " " & t) & "#"
        Case "String"
            If StrPtr(x) = 0 Then
                Dump = "vbNullString"
            Else
                Dump = """" & Replace(x, """", """""") & """"
            End If
        Case "Error"
            If IsMissing(x) Then
                Dump = "Missing"
            Else
                Dump = "CVErr(" & ReMatch(CStr(x), "\d+")(0) & ")"
            End If
        Case "ErrObject"
            Dump = "Err " & x.Number
        Case "Empty", "Null", "Nothing", "Unknown"
            Dump = ty
        Case Else
            If IsObject(x) Then
                Select Case ty
                    Case "Dictionary"
                        Dim keys As Variant
                        keys = x.keys()
                        Dim ar2 As Variant
                        ReDim ar2(x.Count - 1)
                        Dim j As Long
                        For j = 0 To x.Count - 1: ar2(j) = Dump(keys(j)) & ":" & Dump(x(keys(j))): Next
                        Dump = "Dictionary(" & Join(ar2, ", ") & ")"
                    Case "Collection"
                        Dim ar3 As Variant
                        ReDim ar3(x.Count - 1)
                        Dim k As Long
                        For k = 1 To x.Count: ar3(k - 1) = Dump(x.Item(k)): Next
                        Dump = "Collection(" & Join(ar3, ", ") & ")"
                    Case Else
                        Dump = ToStr(x)
                End Select
            ElseIf IsArray(x) Then
                Dim rnk As Integer: rnk = ArrRank(x)
                If rnk = 1 Then
                    Dim lb As Long: lb = LBound(x)
                    Dim ub As Long: ub = UBound(x)
                    Dim ar As Variant
                    If ub - lb < 0 Then
                        ar = Array()
                    Else
                        Dim mx As Long: mx = 8 - 1
                        Dim xb As Long: xb = IIf(ub - lb < mx, ub, lb + mx)
                        ReDim ar(lb To xb)
                        Dim i As Long
                        For i = lb To xb: ar(i) = Dump(x(i)): Next
                    End If
                    Dump = "Array(" & Join(ar, ", ") & IIf(xb < ub, ", ...", "") & ")"
                Else
                    Dump = Replace(ty, "()", "(" & String(rnk - 1, ",") & ")")
                End If
            Else
                Err.Raise 51
        End If
    End Select
End Function

Dump関数以外は前回と変更なしです。

こちらがテストコードです。

Sub dump_test()

    Dim dict As Object
    Set dict = CreateObject("Scripting.Dictionary")
    Dim dict2 As Object
    Set dict2 = CreateObject("Scripting.Dictionary")
    dict2.Add "5", 15
    dict2.Add "6", 16
    dict.Add "7", 17
    dict.Add "8", 18
    dict.Add 9, dict2
    Debug.Print Dump(dict)
    
    Dim lst As New Collection
    lst.Add 5, "6"
    Dim lst2 As New Collection
    lst2.Add 10, "11"
    lst2.Add dict, "12"
    lst.Add lst2
    Debug.Print Dump(lst)
    
End Sub

実行結果はこちらです。

Dictionary("7":17%, "8":18%, 9%:Dictionary("5":15%, "6":16%))
Collection(5%, Collection(10%, Dictionary("7":17%, "8":18%, 9%:Dictionary("5":15%, "6":16%))))

キーの重複はNGなのにキーの存在の確認方法無いのっておかしくない？