Description

ZObjectFactory::createChild when creating the instance of Type List, it checks that the first item is of the correct type. However:

• This is supposed to be checked already, when ZObjectFactory::create does function-schemata validation
• This check is incomplete, because there are resolver types missing (e.g. Z18)
• The check could make sense if we were looking whether everything resolves to a Z4, which is the only thing that the function-schemata cannot do, but this is not being done here

So we need to figure out whether we want to:

• Have an actual type check, and do it properly, or
• Just have a structural validation check so we should remove this block altogether

Completion checklist

• Before closing this task, review one by one the checklist available here: https://www.mediawiki.org/wiki/Abstract_Wikipedia_team/Definition_of_Done#Back-end_Task/Bug_completion_checklist