There was an earlier post with a similar issue when calling Handles.DrawAAPolyLine() from JS. I ran into the same problem in Boo with Handles.DrawPolyLine() in Unity 3.4:
Assets/Scripts/Editor/MyTool.boo(97,29): BCE0017: The best overload for the method 'UnityEditor.Handles.DrawPolyLine(*(UnityEngine.Vector3))' is not compatible with the argument list '((UnityEngine.Vector3))'.
Calling with an explicit list of Vector3 parameters:
compiles and works just fine of course rather impractical. I've called called other Unity functions from Boo with function signatures expecting an array of objects without problems.
I'm assuming this to be a bug?