VB -> C#: wrong conversion of optional struct or decimal ref parameter

VB.Net input code

Private Shared Sub OptionalParams()
    FunctionWithOptionalParams()
End Sub

 Private Shared Sub FunctionWithOptionalParams(Optional ByRef structParam As TestStruct = Nothing, Optional ByRef decimalParam As Decimal = 0)
    structParam = New TestStruct
    decimalParam = 0
 End Sub

Friend Structure TestStruct
    Friend A As Boolean
End Structure

Erroneous output

 private static void OptionalParams()
 {
      TestStruct argstructParam = null;
      decimal argdecimalParam = 0m;
      FunctionWithOptionalParams(structParam: ref argstructParam, decimalParam: ref argdecimalParam);
 }

private static void FunctionWithOptionalParams([Optional, DefaultParameterValue(default(TestStruct))] ref TestStruct structParam, [Optional, DefaultParameterValue(0m)] ref decimal decimalParam)

Expected output

private static void OptionalParams()
{
    TestStruct argstructParam = default;
}

private static void FunctionWithOptionalParams([Optional] ref TestStruct structParam, [Optional, DefaultParameterValue(0)] ref decimal decimalParam)

Details

• Product in use: VS extension
• Version in use: 9.0.0.0
• Did you see it working in a previous version, which? no
• may be, there is a better way to express DefaultParameterValue for a structure

[KunzeAndreas]

private static void FunctionWithOptionalParams(ref TestStruct structParam, ref decimal decimalParam, ref string strParam, ref DateTime dateParam)

would break VB code calling converted C# code (in VB you can omit optional ref params)

[KunzeAndreas]

Optional ByRef xxx As Short = 0S converts to [Optional, DefaultParameterValue(0)] out short xxx

should be [Optional, DefaultParameterValue((short)0)] out short xxx