过程类型对结果的影响：TypeName和TypeOf表现不同的内部子和函数

Question

使用Win64，VBA7 32位上一个简单的程序组合来处理Internet Explorer实例（IE实例），我发现：

一个。该函数正确地将IE实例类型标识为IWebBrowser2;

湾sub错误地将IE实例类型标识为String。

有人会轻轻地分享原因吗？

提前致谢。

Sub SimpleTest()
    Dim iemIE As InternetExplorer
    Dim oDummy As Object

    Set ieIE = New InternetExplorer

    Set oDummy = mahFunction(ieIE)

    mahSub (ieIE)

    ieIE.Quit
End Sub

Function mahFunction(InternetExplorerThatHasMahObject As Variant) As Object
    Dim sFunctionTypeName As String
    Dim bFunctionTestIE As Boolean, bFunctionTestIEM As Boolean

    sFunctionTypeName = TypeName(InternetExplorerThatHasMahObject) 'returns "IWebBrowser2"
    bFunctionTestIE = TypeOf InternetExplorerThatHasMahObject Is InternetExplorer 'returns True
    bFunctionTestIEM = TypeOf InternetExplorerThatHasMahObject Is InternetExplorerMedium 'returns True

    MsgBox sFunctionTypeName & ", " & bFunctionTestIE & ", " & bFunctionTestIEM

    Set mahFunction = Nothing
End Function

Sub mahSub(InternetExplorerToWaitFor As Variant)
    Dim sSubTypeName As String
    Dim bSubTestIE As Boolean, bSubTestIEM As Boolean

    sSubTypeName = TypeName(InternetExplorerToWaitFor) 'returns "String"
    bSubTestIE = TypeOf InternetExplorerToWaitFor Is InternetExplorer 'returns False
    bSubTestIEM = TypeOf InternetExplorerToWaitFor Is InternetExplorerMedium 'returns False

    MsgBox sSubTypeName & ", " & bSubTestIE & ", " & bSubTestIEM
End Sub