Hello, I opened that issue: https://github.com/pharo-project/pharo/issues/4442 <https://github.com/pharo-project/pharo/issues/4442> And I think to fix it we need to actually discuss about what we want. #allButFirst: behaves differently depending on the actual type of sequenceable collection when argument is greater than collection size. For instance: #(1 2) allButFirst: 3. "PrimitiveFailed signaled" (LinkedList with: 1 with: 2) allButFirst: 3. "PrimitiveFailed signaled" (OrderedCollection with: 1 with: 2) allButFirst: 3. "an OrderedCollection() » The question is then, who is right? Should #allButFirst: with an argument greater than the collection size raise an error Or Should #allButFirst: with an argument greater than the collection size returns an empty collection ? I asked a few people about it @ ESUG and it appears that the expected behaviour from #allButFirst: is not the same to all people. We need to decide so we improve consistence of collections. And then, we need to document that with a test :-). Cheers. Julien --- Julien Delplanque Doctorant à lâUniversité de Lille http://juliendelplanque.be/phd.html Equipe Rmod, Inria Bâtiment B 40, Avenue Halley 59650 Villeneuve d'Ascq Numéro de téléphone: +333 59 35 86 40