title: Optional argument in VBA causes error while executing
body: <p>I tried to create procedure that passes 2 arguments, mandatory and optional, before I added optional argument procedure was running correctly. Here is Code:</p>
  
  <pre><code>Sub a2(var As String, Optional num As Integer = 5)
  MsgBox (num)
  End Sub
  
  Sub start_a2()
  a2 ("null_text", 5)
  End Sub
  </code></pre>
  
  <p>When I pass any second argument, running procedure start_a2 fails at 1st line: Sub start_a2(), VBA higlight this line with Yellow and returns Syntax error, but do not provide any details. Second argument is inproperely passed?</p>