Cannot use String.Empty as a default value for an optional parameter

Question

I am reading Effective C# by Bill Wagner. In Item 14 - Minimize Duplicate Initialization Logic, he shows the following example of using the new opt

Answer 1

As a FYI, it looks like the same constraint is imposed on values passed to attribute constructors - they must be constant. Since string.empty is defined as :

public static readonly string Empty

rather than an actual constant, it cannot be used.