Nonsense error message when manually calling EventHandler

Question

If I have an EventHandler with the following signature:

public static void ProcessStuff(object sender, ElapsedEventArgs e)

And If I attempt to manually call the EventHandler like so:

ProcessStuff(this, System.Timers.ElapsedEventArgs.Empty);

Why Do I get the error message:

Argument 2: cannot convert from 'System.EventArgs' to 'System.Timers.ElapsedEventArgs'

EDIT: I also get the same error message If I set the manual call as:

ProcessStuff(this, System.EventArgs.Empty);

Answer 1

If we have a look at https://referencesource.microsoft.com/#System/services/timers/system/timers/ElapsedEventArgs.cs,fa59a445f56b7851

we'll see that System.Timers.ElapsedEventArgs doesn't redeclare Empty:

// No "Empty" (re-)declaration here
public class ElapsedEventArgs : EventArgs {   
    private DateTime signalTime;

    internal ElapsedEventArgs(int low, int high) {        
        long fileTime = (long)((((ulong)high) << 32) | (((ulong)low) & 0xffffffff));
        this.signalTime = DateTime.FromFileTime(fileTime);                        
    }

    public DateTime SignalTime {
        get {
            return this.signalTime;
        }
    }
}

and that's why when we call System.Timers.ElapsedEventArgs.Empty we actually call System.EventArgs.Empty which is of type System.EventArgs:

Console.Write(System.Timers.ElapsedEventArgs.Empty.GetType().Name);

Finally, there's no implicit cast from System.EventArgs to System.Timers.ElapsedEventArgs