Tree of a certain class:

[Peter Schrammel <peter.schrammel@unibw-muenchen.de>]

I wrote a Program:
type 'i tree =
    Empty
  | Item of 'i
  | Section of 'i * 'i

class ['i] ctree =
  object (self : 'a)
    val mutable content : 'i tree = Empty

    method get = content
        
end

class debug =
  object
    method debug = ()
  end

class dtree =
  object
    inherit [#debug] ctree
  end

But the compiler gives me the error:

Some type variables are unbound in this type:
  class dtree :
    object val mutable content : (#debug as 'a) tree method get : 'a
tree end
The method get has type #debug tree where .. is unbound
make: *** [test.cmo] Error 2   

How can make trees of a certain (sub)class ? (I hope there's a simple
solution)

Regards,
Peter
--
Peter Schrammel
UniBw-Muenchen 106/2/116
85579 Neubiberg
ICQ: 5469131