VB -> C#: DefaultParameterValueAttribute doesn't accept default expression

[TymurGubayev]

VB.Net input code

    Sub S(Optional ByRef dt As Date = Nothing)
    End Sub

Erroneous output

//CS0182: An attribute argument must be a constant expression, typeof expression or array creation expression of an attribute parameter type
        public void S([Optional, DefaultParameterValue(default(System.DateTime))] ref System.DateTime dt)
        {
        }

But nothing bad happens if we'd just omit it.

Expected output

        public void S([Optional] ref System.DateTime dt)
        {
        }

Details

• Product in use: VS extension
• Version in use: ae25cdc
• Did you see it working in a previous version, which? No
• Any other relevant information to the issue, or your interest in contributing a fix.