Hi, My first impression is that the error might be caused by using the combination of #:allocation #:virtual and #:init-keyword for the "colour" slot. Since #:init-keyword initializes slot value with a given value, and virtual slots have no actual value, the semantics of such operation is rather unclear.
If your intention is to use the keyword as an argument to the constructor, you should rather provide a custom "initialize" method (and drop the "init-keyword" for the colour slot): (define-method (initialize (self <bar>) args) (next-method) (let-keywords args #t ((colour (or #f some-default-value-you-wish))) (if colour (slot-set! self 'colour colour)))) HTH 2014-12-19 20:46 GMT+01:00 David Pirotte <da...@altosw.be>: > > Hello, > > It would be really nice if someone can help me with the following > unexpected bug: > > http://paste.lisp.org/+33RA > > I don't think i'll be able to solve it by myself, at this level of > knowledge I have > from both goops [implementation I mean, knowledge close to zero] and the > low level > machinery gnome/gobject/gtype.scm > > Many thanks, > David >