What is planned for the code, source and syntaxhighlight tags, really do as an mw:Extension:CodeEditor?
Topic on VisualEditor/Feedback
There is no useful plan at this time. It's on the "probably someday" list.
@Whatamidoing (WMF): probably someday...
Let's do them then as text as a TEMPLATE. Try to edit the code on this page https://ru.wikipedia.org/w/index.php?title=%D0%9E%D0%B4%D0%B8%D0%BD%D0%BE%D1%87%D0%BA%D0%B0_%28%D1%88%D0%B0%D0%B1%D0%BB%D0%BE%D0%BD_%D0%BF%D1%80%D0%BE%D0%B5%D0%BA%D1%82%D0%B8%D1%80%D0%BE%D0%B2%D0%B0%D0%BD%D0%B8%D1%8F%29&veaction=edit&vesection=0
Code tags have many parameters, like templates. Tag can be edited as a template.