You can avoid the warning by having the enum start at 0:
type MouseButton* = enum
mbNone
mbLeft = 1
mbMiddle = 2
mbRight = 3
Since enum default to the value 0, and your enum starts at 1, the default value
of your enum is invalid:
type MouseButton* = enum
mbLeft = 1
mbMiddle = 2
var ml : MouseButton
echo ml #> 0 (invalid data!)
Actually, I think that you can make it start from whatever value you want, eg.
-23, as long as your enum contains a value for 0, but I haven't tested it.
(note that even if you start from a negative number, the default value of the
enum is the one that corresponds to 0, not the first one in the list)
